Qatar Foundation Annual Research Forum Volume 2012 Issue 1
- تاريخ المؤتمر: 21-23 Oct 2012
- الموقع: Qatar National Convention Center (QNCC), Doha, Qatar
- رقم المجلد: 2012
- المنشور: ٠١ أكتوبر ٢٠١٢
201 - 250 of 469 نتائج
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Gene regulatory network inference using information theoretic methods
المؤلفون: Amina Noor, Erchin Serpedin, Hazem Nounou, Mohamed Nounou, Marwa Qaraqe, Lotfi Chouchane and Nady MohamedBackground & Objectives: Gene regulatory network inference is a problem of prime importance in the budding field of systems biology and bioinformatics. The process which uses the information present in the genes to produce functional gene products is termed gene expression, and it can be measured using the microarray technology. The scope of this work is to propose a series of information theoretic algorithms which utilize the gene expression data to reverse engineer gene regulatory networks. Methods: Using information theoretic tools, this work proposes several algorithms to indicate how the genes are interacting with each other in a biological system. One of the advantages associated with these information theoretic algorithms is that they work with minimum assumptions. The concept of mutual information is a fundamental quantity in information theory that is used extensively in this work to measure the degree of dependency between genes. There are situations when two genes are interacting but only via an intermediate gene. By employing data processing inequality and condition mutual information, this work shows the possibility to identify such indirect interactions. Results: The computer simulations illustrate that the proposed information theoretic methods provide some of the most robust algorithms for inferring the topology of gene regulatory networks. While estimating the genetic interactions, it is necessary to put a constraint on the complexity of the network so as to avoid over-fitting the network. To this end, minimum description length principle and Bayesian information criterion are used for model selection. Results performed on both synthetic and realistic gene regulatory networks attest the superior performance of the proposed algorithms. Conclusions: This work describes different information theoretic approaches for determining the possible interactions between genes using gene expression data. The performance metrics used to assess these algorithms are also discussed. It is concluded that information theoretic methods represent powerful tools for inference of gene regulatory networks.
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Molecular epidemiology of human papillomavirus among Arab women in Qatar
المؤلفون: Asha Elmi, Devendra Bansal, Asma Al-Thani, Afaf Al-Ansari, Nady Mohamed and Ali SultanObjectives: Human papillomavirus (HPV) is the most commonly known sexually transmitted agent. To date, few reports are available on the distribution of most prevalent and variant types of HPV in Arab women. Therefore, the aim of this study is to determine the age-specific distribution of HPV types among Arab women being subjected to routine pap smear tests in the State of Qatar. Methods: 1100 pap smears have been collected in ThinPrep vials (BD SurePath™) from Arab women seeking routine gynecological care at the Women's Hospital, Hamad Medical Corporation (HMC) in Doha, Qatar. All the samples were transported to the laboratory in an icebox container. Viral DNA from ThinPrep samples was extracted by QIAamp MinElute virus spin kit according to manufacturer's instructions and was screened for HPV DNA by real-time PCR using L1 HPV specific (GP5+/6+) primers. The type-specific distribution of the viruses was determined by HPV high and low risk typing RT-PCR kits (Sacace Biotechnology, Italy) and PCR-based sequencing. Real-time PCR amplification was carried out in ABI 7500 real-time PCR (Applied Biosystems). Results: Based on the collected data, HPV DNA was detected in 125 women (11.36%), and 15 different HPV genotypes were detected, comprising high-risk and low-risk genotypes. The prevalence of HPV infection was seen in 54.5% Qatari and 45.5% non-Qatari women. With regard to age, 33.5% of all HPVs were found in women 30-39 years of age, 24.8% in women 40-49 years of age, 15.8% in women 50-59 years of age, 5.5% in women over 60 years and 20.4% in women less than 30 years old. Implications and Impact: The study shows that the prevalence of HPV infection in Arab women in Qatar is among the highest in the Arab world compared with previous reports. However, more extensive population-based studies should be undertaken before implementing HPV vaccination.
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Non-acute responses of hematological and molecular markers to intermittent hypoxic exposure and physical exercise in hot environment
Background & Objectives: Both exercise and hypoxia acutely elicit changes in systemic growth factors and cytokines that mediate increases in erythropoiesis, angiogenesis and, perhaps, arteriogenesis. To what extent the down-stream responses to these interventions are inter-related is, as yet, unclear. A role for circulating micro RNAs (cmiRNAs) in the regulation of these processes is a novel prospect. Thus the aims of this study are to investigate the effect of hypoxia and exercise training on relevant growth factors and cmiRNAs in a healthy human cohort. Methods: 18 healthy, Caucasian, male, elite athletes participated in this study. The project was designed as a parallel, two-groups, matched, randomized, longitudinal (pre-, mid-, post-test), two week intervention. One group was exposed to hypoxia (15 hours/day) the other stayed in a normoxic environment. Both groups performed physical exercise in a 10°C hotter environment than usual. The exercise was standardized for both groups and the daily work load was monitored. Blood was sampled under fasting conditions in the morning, to avoid any effects of acute exercise. Hemoglobin (Hb), reticulocytes, erythropoietin, vascular endothelial growth factor (VEGF), interleukin 6 (IL-6), cmiRNAs 144, 146a, 221, 222 were tested in blood and sera. Results: In the normoxic group decreases from pre- to mid- and post-test were found for Hb (p=0.011, p=0.002) and IL-6 (p=0.028, p=0.008). However, in the hypoxic group several changes were apparent. In this group Hb changed at the pre- to mid-test (p=0.013), reticulocytes also increased from pre- to mid-test (p=0.066), erythropoietin increased from pre- to mid- and post-test (p=0.008, p=0.008). VEGF also showed a tendency to increase from pre- to mid-test (p=0.085) and increased from pre- to post-test (p=0.011). The 2-ΔΔCT values for cmiRNAs 221 and 222 showed an increasing trend at the post-test time point but did not reach statistical significance. Conclusions: Hypoxia stimulated several cytokines and growth factors mediating erythropoiesis and angiogenesis, which might have counteracted the plasma volume related decrease in Hb in the normoxic group. While there were changes in cmiRNAs (221 and 222) these were not statistically significant, perhaps due the small study cohort, which is currently being expanded to confirm these results.
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Fetal and perinatal determinants of neonatal mortality in the State of Qatar: A PEARL study analysis
Background and Objective: The State of Qatar has achieved maternal, neonatal and perinatal survival rates which are comparable to many high income countries, both from the West and East. Our study aims to analyze fetal and perinatal determinants of Qatar's neonatal mortality rate (NMR) during 2011. Methodology: A PEARL Study (Perinatal Neonatal Outcomes Research Study in the Arabian Gulf), a joint collaborative research project between Hamad Medical Corporation (HMC) Qatar and University of Gloucestershire United Kingdom, is Qatar's prospective national perinatal epidemiological Study funded by Qatar National Research Fund. The study is quantifying maternal, neonatal and perinatal mortality, morbidities and their correlates by establishing a national neonatal perinatal registry for Qatar called Q-Peri-Reg. Data on live births and neonatal mortality were collected from all public and private maternity facilities in Qatar during 2011. Data on fetal and perinatal determinants was ascertained from maternal obstetric and delivery room record on predesigned performas. Univariate and multivariate regression analysis was done using Epi Info and SPSS-20. Results: Qatar's NMR during 2011 was 4.9. The incidence of low birth weight in Qatar is 11% and the incidence of preterm deliveries 10.7%. 10% of the babies required delivery room resuscitation. The relative risk of neonatal mortality was higher and statistically significant with fetal growth (p<0.001), fetal weight at birth (p<0.001), fetal gestation at birth (p<0.001), APGAR score at 1 and 5 minute (p<0.001) and the need for delivery room resuscitation (p<0.001). The RR of neonatal mortality increased (Table 1) with decreasing birth weight (p<0.001) and gestational age (p<0.001). Conclusion: Further improvement in Qatar's neonatal mortality is possible by addressing the high incidence of low birth weight and preterm deliveries. Better maternal nutrition, improved antenatal care, birth spacing and best obstetric and neonatal practices at delivery are likely to be most helpful.
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Evaluation of glycemic abnormalities in patients with Beta Thalassemia major using continous glucose monitoring system (CGMS) and oral glucose tolerance test (OGTT): A pilot study
المؤلفون: Mohamed Abdeldaem Yassin, Ashraf Tawfiq Soliman and Ahmed Said AlawwaIntroduction: Both insulin deficiency and insulin resistance are reported in patients with β thalassemia major (BTM). The use of CGMS among the different methods for early detection of glycaemic abnormalities has not been studied thorough. The aims of this study are: 1. to detect glycemic abnormalities in young adults with BTM using fasting blood glucose (FBG), (OGTT), 72-h continuous glucose concentration by CGMS, and serum insulin and C-peptide concentrations; 2. To compare the results of these two methods in detecting glycemic abnormalities in these patients; and 3. To calculate (HOMA), and (QUICKI) in these patients. In order to evaluate whether glycemic abnormalities are due to insulin deficiency and/or resistance. Materials and methods: Randomly selected young adults (n = 14) with BTM . All patients were investigated using (OGTT) 75 gram of glucose and 72-h by CGMS. Fasting serum insulin and C-peptide concentrations were measured and HOMA-B, HOMA-IR were calculated accordingly. Results: Using OGTT, 5 patients had impaired fasting glucose (IFG) (Fasting BG from 5.6 to 6.9 mmol/L). Two of them had impaired glucose tolerance IGT (BG from 7.8 and < 11.1 mmol/L) and one had BG = 16.2 mmol/L after 2-hrs (diabetic). Using CGMS in addition to the glucose data measured by glucometer (3-5 times/ day), 6 patients had IFG. The maximum (postprandial) BG recorded exceeded 11.1 mmol/L in 4 patients (28.5%) (Diabetics) and was > 7.8 but < 11.1 mmol/L in 8 patients (57%) (IGT). The mean values of HOMA and QUICKI in patients with BTM were < 2.6 (1.6± 0.8) and > 0.33 (0.36±0.03) respectively ruling out significant insulin resistance in these adolescents. There was a significant negative correlation between the β-cell function (B%) on the one hand and the fasting and the 2-h BG (r= -0.6, and - 0.48, P< 0.01 respectively) on the other hand. Ferritin concentrations were negatively correlated with the β-cell function (r= -0.41, P< 0.01). Conclusion: CGMS has proved to be superior to OGTT for the diagnosis of glycemic abnormalities in adult patients with BTM. In our patients, defective β-cell function rather than insulin resistance appeared to be the cause for these abnormalities.
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Ethnic and gender differences in skin auto-fluorescence
Background: The AGE reader is a non-invasive device that measures tissue accumulation of advanced glycation endproducts (AGEs) through skin auto-fluorescence (AF) and gives prediction of cardiovascular risk. For the risk prediction, the AGE reader uses a single reference curve, for both females and males, obtained from Caucasian subjects. Based on these reference curves, clinical cut-offs for a low, medium and high AF have been made. This study examines whether these reference values can be used for ethnic populations seen in Qatar. Furthermore, we assess whether gender and smoking affect skin AF in this particular population. Methods: Skin AF was measured in 200 Arabs, 99 South Asians and 35 Filipinos. Using multivariate linear regression analysis and adjusting for the covariates age and the presence of type 2 diabetes, we assessed whether ethnicity, smoking and gender were associated with skin AF. Results: The Arabs and the Filipinos had a significant higher skin AF then the South Asian population (0.272 (95% CI: 0.138, 0.406), p <0.001 and 0.354 (95% CI: 0.147- 0.561), p=0.001 respectively). This is equivalent to a horizontal shift of 14.6% and 19.0%, respectively. Also, skin AF was significantly higher in women compared to men (0.432 (95% CI: 0.307, 0.558), p <0.001). Smoking was positively associated with skin AF (0.21 (95% CI: -0.01, 0.41), p=0.056), with an increasing effect of number of pack-years smoked on AF (p=0.024). Conclusions: The results of this study suggest that the existing reference values should be expanded for ethnicity, gender and smoking. These results also indicate that the use of the AGE reader in clinical settings should be used with caution, since the clinical cut-off points are dependent on various factors such as ethnicity that still need to be studied in greater detail.
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Endothelial dysfunction in morbidily obese young Qataris
Background & objectives: The prevalence of metabolic syndrome (MetS), including obesity, dyslipidemia, hyperglycemia and hypertension, associated with an increased predisposition to cardiovascular disease (CVD), is especially high in the Middle East, primarily amongst young Qataris. Both insulin resistance and endothelial dysfunction have been proposed to contribute to the pathogenesis of CVD in obese patients. Recent reports have shown that abdominal adipose tissue depot-specific differences impact on endothelial vasomotor function, with the visceral/omental environment considered more pathogenic. It is, however, unclear how severe the effect would be on a relatively young obese population. This study investigated endothelium-dependent relaxation of small arteries embedded in two adipose tissue depots, the sub-cutaneous and the omental. Methods: Arteries were isolated from omental (OM) and subcutaneous (SC) adipose tissues collected from consented Qatari patients undergoing bariatric surgery for weight reduction. The arteries (ID ~251 µM for SC and ~ 262 µM for OM) were cut into segments (~2 mm) and mounted on a dual wire Myograph (510A) for measurement of isometric tension. Cumulative concentration-response curves were constructed for acetylcholine (1- 10000 nM, the classical endothelium-dependent relaxant) in the absence or presence of Nω-Nitro-L-arginine methyl ester (L-NAME,100 µM, nitric oxide synthase inhibitor) on initial tone generated with noradrenaline (5 µM). Relaxation to sodium nitroprusside (SNP) and prostaglandin E2 were also recorded. Results: The mean age of the patients was 32 years, their blood glucose 5.6 mmol/L, Insulin 19.3 µU/ml , the index of insulin sensitivity/resistance (HOMA) 5.5 and body mass index 43.4 Kg/m2. Relaxation to Ach was significantly attenuated in OM vessels (Emax 51±9 %) compared with SC vessels (Emax 79±6 %, p<0.05) from same patients. The Ach response was further reduced in the presence of L-NAME. In contrast, the relaxation to SNP and PGE2 were greater in OM vessels compared with the SC vessels. Conclusions: These results demonstrate adipose tissue depot-specific differences in the impact of obesity on endothelial function in morbidly obese, insulin resistant, young Qataris, with a marked reduction in endothelium NO-dependent relaxation in the OM compared with SC vessels. The reversibility of this lesion by weight loss are yet to be ascertained.
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Effect of social and environmental factors on the prevalence of autism in Qatar
المؤلفون: Fouad AlshabanAutism spectrum disorders (ASD) are a group of neuro-developmental disabilities common in childhood characterized by impairments in social interaction, communication skills, and patterns of activities. Background: The symptoms of ASDs typically are present before age 3 years and often are accompanied by abnormalities in cognitive functioning, learning, attention, and sensory processing. A formal diagnosis is generally not made until the age of five. The vast majority of cases of autism are idiopathic, the best scientific evidence available to us today points toward a potential for various combinations of factors, namely multiple genetic components and certain environmental and socio-economic factors. Timing of exposure during the child's development (before, during or after birth) may also play a role in the development or final presentation of the disorder. Objectives: To estimate the effect of certain socio-economic and other risk factors on the prevalence of autism in Qatar. Methods: The target population for this study are children diagnosed with autism attending the Shafallah Center for children with special needs. Clinical evaluation is conducted by a developmental psychologist, and/or pediatrician, it includes a medical, developmental, and behavioral history; a standard physical and neurological examination, In addition, the Autism Diagnostic Interview (ADI-R), and Autism Diagnostic Observation Schedule-G (ADOS-G) will be administered. Results: Preliminary analysis of 171 subjects showed the highest prevalence among age group 7-14 years (61%). Male/female ratio was 82%/18%, which is around 5/1. Other factors like consanguinity, education, and family income found to have an effect on the prevalence of the disease in Qatar. Conclusions: Obtaining a reliable estimate is important in planning for providing the best health care and educational services needed to improve the overall outcome of autism in Qatar.
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Early detection of peripheral neuropathy by examining virtual perception of lower extremity join position
المؤلفون: Bijan Najafi, Gurtej Grewal, Rashad Sayeed, Robert Menzies, Talal Talal, Lawrence Lavery, Mahmoud Zirie and David ArmstrongBackground: Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes that affects nerve functions and may occur in 25% of patients with 10 or more years of diabetes and up to 50% with 20 years of diabetes. Patients with DPN experience a high incidence of injuries while walking and have a low level of perceived safety. In certain cases the impaired judgment - mainly due to impaired proprioceptive feedback - can cause obstacle collision leading to falls and injuries. The subtle early findings that are indicative of postural instability are difficult to accurately assess from a clinical examination, and gait laboratory assessment is not currently available or practical. Thus, unfortunately, many patients that are "at risk for falls" are undiagnosed. Objectives: An innovative virtual obstacle crossing (VOC) paradigm using wearable sensors was developed in attempts to detect lower extremity nerve damage due to DPN. Methods: Sixty-eight participants including diabetes with no, moderate and severe neuropathy and aged-matched healthy controls were recruited. Severity of neuropathy was quantified using vibratory perception threshold (VPT) values. The ability of perception of lower extremity was quantified by measuring the rate of obstacle crossing success (OCS), reaction time (TR), and foot position while crossing a series of virtual obstacles with various heights. Results: Results suggest VOC test allows separating between groups. All proposed parameters were significantly deteriorated by increasing neuropath severity (p<0.05). Results also suggest a significant correlation between TR and VPT values (r=0.5, p<10-5). Finally, results suggest a significant deterioration in balance due to diabetes, irrespective of neuropath severity (p<0.05). Conclusions: The results proposed the benefit of virtual obstacle crossing as an objective method for detecting peripheral neuropathy at an early stage. This is based on the reasoning that lower extremity proprioception decreases with increasing nerve damage. The increased reaction time, decreased OCS, and increased sway of the DPN patients in this study suggests their decreased proprioception, and, therefore, increased peripheral nerve damage. Further studies should be addressed to compare VOC with other standard methods to confirm whether VOC can detect DPN earlier than current methods.
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Endothelial cells provide a niche for placental hematopoietic stem cell expansion
المؤلفون: Christophe Raynaud and Arash RafiiUmbilical cord blood (UCB) is an attractive source of hematopoietic stem cells (HSCs). However, the number of HSCs in UBC remains limited and the attempts to amplify them in-vitro remain of poor efficiency. Several publications document amplification of HSC/progenitors with endothelial or mesenchymal cells, but the lack of homogeneity in culture conditions or HSC qualification impairs direct comparison of these results. Therefore, we compared the possible HSCs amplification using placental mesenchymal progenitors and Akt-activated umbilical vein endothelial cells. After HSCs isolation from UCB (defined as Lin-CD45-CD34+CD38-CD90+) on confluent feeder layer, the number of total cells and HSCs were monitored over 21 days. We demonstrate important cellular expansion on both niches. Most of the expanded cells were differentiated when characterized by flow cytometry. Only endothelial cells could trigger HSCs amplification with a pick at 14 days. Those amplified HSCs were able to differentiate in all cell lineages as attested by colony forming assays. Mesenchymal progenitors mainly triggered the amplification of CD38+ cells previously defined as precursors. A competitive assay demonstrated that HSCs had an in-vitro preference to interact with endothelial cells. Cytokines and transcriptomic analysis of our feeders indicate the mechanisms involved in HSC amplification and differentiation in both cases.
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Dietary composition and postprandial inflammation: Implications for human health
المؤلفون: Amanda Brown, Ken Olson and Mohammad KhaledInflammation, in general, has been found to be associated with many human health complications. Postprandial inflammation, provoked soon after ingesting a meal, is transient in duration, but with dreadful consequences on human health over a period of time depending on the compositions of the meal. However, many populations, particularly in the Western countries, are in a constant postprandial state, which is likely to initiate insulin resistance (IR) resulting in type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD). Postprandial inflammation is dependent on the food quality and quantity, mostly in terms of its energy/calorie content and its nutritional value. Micronutrients, such as minerals and vitamins, constitute the nutritional value of a food, while macronutrients, such as carbohydrate, protein and fat/lipid, are basically the sources of its energy/calorie content. Since energy content varies significantly between carbohydrates (4 kcal/g) and fats (9 kcal/g), the objective is, therefore, to assess postprandial inflammation of an isocaloric, isonitrogenous high carbohydrate (66%) and low fat (20%) diet (HC) versus a high fat (56%) and low carbohydrate (30%) diet (HF), by measuring diet-induced postprandial thermogenesis (DIPT). Healthy, never-obese, postmenopausal, Caucasian female subjects (n=12) participated in this study for 3 weeks each in a crossover design. Fat-free mass (FFM) and fat mass (FM) were measured by under-water weighing before and after each diet. Resting metabolic rate (RMR) was assessed fasting and for five 40-minute periods over a 6 hours DIPT after ingesting 14.3 kg/FFM of either HC or HF diet. A low respiratory quotient (RQ), during the measurement of DIPT, is usually indicative of lipid peroxidation, an important index of inflammation. RQ after ingesting HC diet was significantly higher in this study, while it was significantly lower for HF diet, thus indicating a higher inflammatory response due to fat. A significant elevation of free fatty acid (FFA) was also observed after ingesting HF diet, which is well-known to be associated in the pathophysiology of T2DM, a significant risk factor for CVD. Further studies are necessary to understand the role of postprandial inflammation in human health.
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Congenital and genetic disorders in the Sultanate of Oman: Genetic service needs assessment
المؤلفون: Anna RajabBackground and Objectives: In the past 40 years Oman has witnessed remarkable social and economic growth, which is best reflected in the well-organized and efficient healthcare system. It has been anticipated that a change in disease pattern would be brought about by improvement in the quality of life, comprehensive healthcare facilities and successful control of communicable diseases. Although genetic and congenital disorders are increasingly observed in medical practice, there were no convincing available data to support these observations. The study was performed over the years 2010-2012 in order to assess the population needs for genetic services. Methods: A population-based study was conducted with detailed assessment and interviews of more than 3000 Omani mothers. Randomization was performed by counting the number of nationals in each geographical area and places of residence, and interviewing one mother per 600 Omani nationals in all geographic locations throughout the country. The collected data were verified with available hospital records and reports and analyzed. Results and Conclusions The population-based study revealed that 10% of Omani mothers reported congenital and genetic disorders causing morbidity in their offspring. Congenital disorders with mental disability accounted for over half of the reported morbidity, and a third of these reports had familiar recurrence. Morbidity and mortality from congenital and genetic causes that have been derived from this study reflect the situation in traditional Muslim community with high rate of inbreeding where communicable diseases were successfully controlled, and prevention measures are still in a preparatory phase. The current study confirmed that congenital and genetic conditions are the major contributors to childhood morbidity and mortality, and handicap prevalence in the Sultanate of Oman, indicating the need to prioritize future healthcare and planning, in view of their significant financial, social and research relevance.
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Cloning, overexpression and molecular characterization of human mast cell carboxypeptidase A
المؤلفون: Sayed Kamel Goda, Aref Kyyaly, Asia Al-Jabiry, Andrew Walls and Muhammad Al SayrafiBackground: Mast cell proteases represent major protein components of secretory granules. The proteases are classified into a chymases, tryptases and carboxypeptidase (hMC-CPA). Little is known about the function of human lung carboxypeptidase A (hMC-CP) except for its ability to cleave angiotensin I. This suggests that the human mast cell carboxypeptidase A may play a role in the hypertension disease. Objectives: 1) Making human lung cDNA library and isolating the human lung carboxypeptidase A; 2) Cloning and expressing the full length PCR products into the overexpression vector pET28a and into pYES2; 3) Molecular characterization of the recombinant proteins. Methods: Human lung cDNA was prepared and PCR was carried out using DNA primers of the carboxypeptidase A (hMC-CPA).The isolated gene fragment was subcloned into the overexpression vector pET28a and transformed into E. coli DE3 for expression. The gene was also subcloned into the pYES2 vector for expression in yeast. The expression in E. coli has been validated by Western Blot analysis using four different antibodies. The purification was carried out using Ni²+ column chromatography. The recombinant protein was further characterized using MS and peptide amino acid sequencing. Results: We cloned and overexpressed the gene in E.coli using the His-tag vector pET28a. The protein expression in E. coli has been validated by Western blot analysis using four different carboxypeptidase A antibodies. The protein however, has been expressed in the form of inclusion bodies. Despite the fact that we could obtain soluble CPA at lower IPTG concentration and lower induction temperature we decide to subclone and express the gene in Saccharomyces cerevisiae. We successfully managed to subclone the gene in pYES2 vector and to produce a soluble form of the CPA in Saccharomyces cerevisiae. The hrMC-CPA expressed in Saccharomyces cerevisiae in frame with six His-tags. The protein therefore was purified by one step purification using Ni column. Conclusion: The cloning and overexpression of the CPA in soluble form will pave the way for molecular characterization studies of this enzyme and to shed more light on its biological function.
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Genome-wide association study of prostate cancer in Arab populations: Identification of three genomic regions with multiple consecutive prostate cancer susceptibility loci
Background: Prostate cancer is the most common malignancy in many industrialized countries and the second cause of cancer-related death in Europe and the United States. The incidence of the disease has been increasing in Arab populations. Large databases focused on genetic susceptibility to prostate cancer have been accumulated from population studies of different ancestries, including Europeans and African-Americans. Arab populations, however, have been only rarely studied. Genetic susceptibility to prostate cancer differs significantly across ethnicities. It would be of interest to identify the common alleles associated with prostate cancer risk in Arab population. Methods: With Affymetrix Genome-Wide Human SNP Array 6.0, we conducted a genome-wide association study (GWAS) in which 534,781 single nucleotide polymorphisms (SNPs) were genotyped in a Tunisian cohort of 92 cases with prostate cancer and 131 age-matched controls. Then we extended the study to evaluate promising associations of 11 SNPs, identified by GWAS, in a cohort of individuals of Arab ancestry living in Qatar and Saudi Arabia (155 cases and 182 controls) using TaqMan® SNP Genotyping Assays. Results: We identified 3 consecutive regions significantly associated with prostate cancer risk on chromosome 9, 17 and 22, including 18 SNPs (P=8.52×10-5 to P=2.18×10-6) in the Tunisian population. Three previous reported common loci associated with prostate cancer at 17q21 containing STAT3 gene in the Caucasian population were confirmed. Two novel chromosomal regions associated with prostate cancer contain candidate susceptibility genes: SMARCA2, LOC646851and SUN2 were revealed. Conclusion: Our findings, identifying novel GWAS prostate cancer susceptibilty loci, indicate that prostate cancer genetic risk factors could be ethnic specific.
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Chest injury among young population in Qatar
Background: Traumatic chest injury (TCI) constitutes quarter of trauma-related deaths worldwide. Objective: To identify the pattern and outcome of TCI in Qatar in relation to age. Methods: Data were collected from all patients who sustained TCI between January 2008 and December 2010 in Qatar. Patients were classified and analyzed in 3 age groups (group 1 <18, group 2 between 18 and 45 and group 3 above 45 years). The multivariate regression analysis was performed for the predictors of mortality. Results: Of 5118 cases admitted to the section of trauma, 1355 (26.5%) had TCI (10%, 71% and 19% in group 1, 2 and 3 respectively). Children (<18 years) had more traffic-related injury, intubation (42%), high ISS (25%), head injury (44.3%), and liver injury (16%) in comparison to other groups. The overall mortality rate was 13% (28.5 %, 11.3% and 12% in group 1, 2 and 3 respectively). Traffic-related death was 13% while fall-related death was 7%. In comparison to survival, no survival was associated with higher rate of head injury (73% vs 33%), intubation (81% vs 19%) and high ISS (64% vs 14%), P=0.001. Independent predictors for mortality included age (OR 0.98; 95% CI: 0.97-0.99) ISS (OR 1.05; 95% CI: 1.03-1.07) and intubation (OR 9.5; 95% CI: 6.09-14.29). Conclusion: TCI is an alarming problem in Qatar with a high mortality. Young males are the most exposed population that deserves more emphasis on injury prevention. Regulatory efforts by the government at working sites and in the strict enforcement of traffic laws would likely reduce morbidity and mortality.
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Application of PCC and M-FISH assays to detect biomarkers-and stage specificity-of cancer of different origins and to improve cancer therapy regimens
المؤلفون: Firouz Darroudi and Michael LongBackground: Cytogenetics of solid tumors in general is negatively affected by culturing artifacts such as preferential clonal expansion and introduction of chromosomal rearrangements, thus making it difficult to discriminate between primary changes and secondary events. Considering that chromosomal instability is a hallmark of cancer even at the precursor cancer level, it is of a great importance to devise a method of comprehensive chromosome analysis of cancer and cancer precursor cells that can bypass culturing problems as much as possible and that can provide informative karyograms of primary tumors at non-mitosis stages of the cell cycle. Consequently, we have developed a novel approach using chemically induced premature chromosome condensation (PCC) method and combined it with the technique of whole genome chromosome painting assay (M-FISH), in which chromosomal constitution of cancer cells could be detected independent of mitosis and without culture artifact within just three hours after receiving the biopsies. Objectives: 1. To perform karyotype analysis; 2. To define stage specificity; 3. To detect hall-mark(s) of cancer of different origins; 4. To improve therapy regimen by elucidating sensitivity of tumors and patients' lymphocytes to radiation and/or cytostatic drugs. Methods: Chemically-induced PCC method was applied on primary tumors (such as, cervical-, head and neck-, breast- and prostate-cancer) to generate metaphases. Afterwards, these preparations underwent M-FISH. Results: This unique/novel combined assay can give for the first time the possibility to assess genetic instability by detecting spontaneously occurring chromosomal instability (structural and numerical) in different types of primary tumors, as well as adjacent normal cells. It may open up the possibility to detect biomarker(s) for specific type of tumors, that can be used as screening tests. Furthermore, the sensitivity of specific types of tumors as well as patient's normal lymphocytes to cytostatic drugs and/or radiation can be determined. Conclusion: The unique combined state of the art assay we developed can lead to detect biomarker(s) for specific type of cancer. Moreover, for the first time therapy regimen can be individually designed based upon detecting tumors as well as patient's lymphocytes sensitivity.
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Cultural aspect of pedestrian injuries amongst expat workers in Qatar: An opportunity for an injury prevention program
Background: In the State of Qatar, the majority of workers are expatriates from different ethnicity and culture. Most of them are liable to pedestrian motor vehicle crashes (MVC). We sought to understand the anatomy, time and date of injuries amongst expat workers in relation to their country of origin, culture and traditions. Methods: Retrospective analysis of prospectively collected data obtained from trauma registry was done. Analysis includes all traffic related pedestrian injuries admitted to the trauma surgery service at Hamad General Hospital, the only level I trauma center in Qatar, between January 2009 and December 2011. Demographics, time and season of injuries, ISS, type of injuries, anatomical body parts injured, ethanol intake, hospital length of stay, length of ICU stay, and mortality were analyzed. Results: Of the 4997 injured patients admitted to the section of trauma, 603 (12.1%) were pedestrians [(non-Arab (75%), Arabs (17%) and nationals (8%)]. The mean age was 31.8±17 years with 93% males. The mean ISS was higher in those who were injured on Friday and Saturday (16±10 and 15±10; p=0.32) in comparison to the week days. Moreover, mean ISS was also relatively high in those who got injured during the winter season (15.2±11) compared to other months (13.5±10). Head injury (45%) was the most common injury followed by injury of the lower limbs (37%), upper limbs (24%), ribs (22%), pelvic area (20%), lung (17%), spleen (10%), liver (7%) and kidney (4%). Alcohol intake was highest amongst expatriate workers from Nepal and Sri Lanka. The median hospital length of stay was 7 (range 1-312) days, TICU stay was 4 (range 1-150) days and ventilator days was 2 (range 1-36) days. The overall mortality was 11.6 % (83% non-Arabs, 9% Arab non-Qataris and 8% Qataris; p=0.08). Conclusion: Majority of the pedestrian injuries involved expatriate workers with poor socio-economic status and cultural barrier in communication. Injury severity was higher in winter season particularly during weekends. These injuries pose economic burden to the healthcare system of the country and thus need urgent injury prevention measures such as education and awareness campaigns among expat workers in Qatar.
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Acute effects of blood transfusion on pituitary gonadal axis and sperm parameters in young males with sickle cell disease (SCD): A pilot study
Objective: To evaluate semen parameters and measure serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) concentrations before and 7 days after packed red cell transfusion (PCTx) in adults with sickle cell disease (SCD). Methods: This prospective study investigated 18 young adults with transfusion-dependent SCD, aged 20.7 +/- 2.88 years, with full pubertal development (Tanner's stage 5) (euogonadal), and capacity to ejaculate. Their serum ferritin levels were 1488 +/- 557ng/ml. Basal serum concentrations of FSH, LH, T and IGF-I were evaluated before and 7 days after packed red cell transfusion (PCTx). We studied the effect of PCTx on semen parameters and the endocrine functions in these 18 patients with SCD. Results: Following PCTx, a significant increase of Hb from 8.5 +/- 1.17 g/dl to 10.5 +/- 0.4 g/dl was associated with increased testosterone (12.3 +/- 1.24 nmol/L to 14.23 +/- 1.22nmol/L and gonadotropin concentrations. Total sperm count increased significantly from 87.4 +/- 24.6 million/ml to 146.2 +/- 51.25 million/ml total progressive sperm motility (TPM) from 40.8 +/- 11.1 million/ml to 93.4 +/- 38.3 million/ml, and rapid progressive sperm motility progressive motility (RPM) increased from 29.26 +/- 8.75 million/ml to 67.4 +/- 29 million/ml. After PCTx the total sperm count, TPM and RPM were significantly higher in the ETx group versus the TTx group. Before and after PCTx, testosterone concentrations were correlated significantly with sperm total count, volume, TPM and RPM (r= 0.53, 0.55, 0.42 and 0.38 respectively, p= 0.01). Before and after PCTx, hemoglobin concentrations were correlated significantly with sperm count, TPM, RPM and percentage of sperms with normal morphology (r= 0.60, 0.69, 0.66 and 0.86 respectively, p <0.001) Conclusion: Our study suggests that in males with SCD, blood transfusion associated with significant acute enhancement of sperm parameters and with an increased concentration of testosterone, LH and FSH. Improvements of sperm parameters were significantly higher in the exchange transfusion (ETx) group versus the top-up (TTx) group. These 'acute' effects on spermatogenesis are reached with an unknown mechanism(s) and suggest a number of pathways that need further human and/or experimental studies.
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Prognosis of neurogenic dysphagia by neuromuscular electric stimulation (NMSE) therapy versus NMSE coupled with conventional swallowing training in subacute cases in Qatar
المؤلفون: Amal Idres Ahmad and Mohmad Sajed HusainTo study the effects of VitalStim therapy coupled with conventional swallowing training on recovery of neurogenic dysphagia, a total of 30 dysphagia patients were randomly selected among subacute post-traumatic brain injury and cerebrovascular accident cases. The cases were evenly divided into two groups: neuromuscular electric stimulation (NMSE) group, and NMSE plus conventional swallowing therapy group. Before and after the treatment, swallowing function was evaluated by using fiberoptic endoscopic evaluation of swallowing (FEES) test and swallowing ability function evaluation (SAFE). Outcomes were analyzed for changes in oral and pharyngeal phase dysphagia severity, diet consistency and improvement from non-oral to oral intake. There were significant differences in the SAFE score in each group before and after treatment. After 8-week treatment, the SAFE score was significantly greater in the NMSE therapy plus conventional swallowing training group than in the NMSE therapy group. It was concluded that VitalStim therapy coupled with conventional swallowing training was conducive to recovery of post-stroke dysphagia.
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Investigating poly (ADP-ribose) polymerase-1 (PARP-1) activation in obesity associated DNA damage and pro-inflammatory senescence
المؤلفون: Houari Boumediene Abdesselem, Aisha Madani and Nayef MazloumObesity has increased at an alarming rate over the past three decades. It is likely to be caused by increased caloric intake combined with genetic predisposing factors and is a major risk factor for type 2 diabetes (T2D) and cardiovascular disorders. Obesity is linked to chronic inflammation, which was proposed as a cause for insulin resistance and T2D. However, the molecular mechanism of obesity driven T2D still lacks knowledge and thus is inaccessible to therapeutic intervention. In our research, we are exploring the molecular mechanism underpinning this association and aims to identify novel therapeutic targets for the rapidly growing population of obese individuals living with diabetes. The obese state creates a microenvironment within the adipose tissue that is susceptible to the accumulation of reactive oxygen species (ROS). Accumulated ROS causes oxidation of macromolecules such as DNA. Oxidative DNA damage encompasses a variety of DNA lesions such as DNA single-strand breaks (SSBs) and DNA double-strand breaks (DSBs) including non-telomeric and telomeric DSBs. Broken or dysfunctional telomeres have been hypothesized as a cause of cellular senescence, a state of irreversible cell cycle arrest observed in aging illnesses and even in obesity with accumulation of senescent adipocytes. A major player in detecting and defending against accumulation of oxidative DNA damage is PARP-1. PARP-1 activation has been shown to be associated to diabetes and obesity. We are exploring the role of PARP-1 in ROS-induced senescent and inflamed adipocytes by using a combination of biochemical, molecular and cell biological assays in primary human and mice adipocytes treated with hydrogen peroxide (H₂O₂) as a source of ROS.
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Public attitudes towards participation in Biobank Qatar
المؤلفون: Eman Nasrella and Brian ClarkBackground and Objectives: Biobank Qatar is a research enabling infrastructure requiring members of the Qatari public to donate health and lifestyle information coupled to biological samples to enable research towards better prevention, diagnosis and treatment of diseases common in Qatar. Building a biobank depends on the willing participation of the public. Recruitment of participants requires insight into public knowledge of biobanking, public willingness and an understanding of motivators and the barriers. This study reports public opinion in Qatar and aids the communication campaign that facilitates recruitment. Methods: A qualitative survey was undertaken, by means of recorded structured interviews, with 100 members of the Qatari public including Qatari nationals and long-term expatriate residents (resident for more than 5 years). Results: Qatari nationals believe that Biobank Qatar raises Qatar's international profile. Volunteering is seen as a charitable act, compatible with Islam, to help future generations. Long term residents buy-in less to the benefits to Qatar. Qatari nationals assume confidentiality due to trust in their government. Long-term residents fear their information might be used against them (e.g. in the work place). Fear of infection through contaminated equipment was raised. There is lack of understanding on the process of donating blood. Questions arose over the biobank location, proximity to workplaces and how accessible it would be. Participants suggested commitments with families and employers as potential barriers. The public favor communication using a range of media. Participants particularly suggested raising awareness through gatherings and social events. Some participants volunteered to "spread the message" amongst social groups by acting as "biobank champions". Conclusions: Although limited by scale, scope and composition of the sample, this study provides a way-finder for public opinion related to biobanking for biomedical research. The public support Biobank Qatar, even with limited knowledge of our work. Qatari nationals were particularly supportive and are motivated by national pride, progress and making personal contributions to a healthier future for future generations. This study is useful in guiding our communications and recruitment plans and will be the basis for further sociological studies of the Qatari public and their support for biomedical research.
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STIM1 phosphorylation in Xenopus oocytes during meiosis
المؤلفون: Maya Dib and Khaled MachacaStromal interaction molecule 1 (STIM1), the ER calcium sensor, couples to Orai1, the calcium channel, and mediates store-operated calcium entry (SOCE). STIM1 localizes to the ER membrane. Following Ca²+ store depletion, STIM1 forms puncta that localize to the cortical ER and binds Orai1 to allow Ca²+ influx. The egg's competency to activate at fertilization is dependent on its ability to generate a fertilization-specific Ca2+ transient. This is achieved through remodeling of its calcium signaling machinery during oocyte maturation. Oocyte maturation is driven by kinase cascade including MOS- mitogen-activated protein kinase (MAPK) - maturation promoting factor (MPF). Coordinately, SOCE inactivates during maturation. This inactivation is due to internalizing of Orai1 and the inability of STIM1 to form puncta. Here we show that MPF phosphorylates STIM1. Through molecular and pharmacological manipulation we are able to differentially activate the kinases along the kinase cascade that drives oocyte maturation. STIM1 phosphorylation in these studies was monitored through a mobility shift on SDS-PAGE. When MPF is activated a mobility shift is observed. However, this is not the case when only Mos or the MAPK cascade were active. Our next step is to determine the role of MPF phosphorylation of STIM1, because previous studies have argued that phosphorylation does not inhibit STIM1 clustering during meiosis. Our data argue that MPF is the primary kinase that phosphorylates STIM1 during meiosis.
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Photodynamic therapy for hair removal
المؤلفون: Mohamed Ali, Amr Zaher, Carmen Ali and Khalid A. Al-SaadBackground: Unwanted hair is one of the most common medical problems affecting women of reproductive age inducing a lot of psychological stress and threatening their femininity and self-esteem. Old methods of removing unwanted hair include shaving, waxing, chemical epilation, and electrolysis, all of which have temporary results. However laser-assisted hair removal is the most efficient method of long-term hair removal currently available. It is desirable to develop a reduced-cost photodynamic therapy (PDT) system whose properties should include high efficiency and low side-effects. Objectives: The aim is to develop an adequate PDT system including helium-neon (He-Ne) laser and its effect on the photodynamic activity of methylene blue (Figs. 1 and 2) in biological experiments. Method: Mice skin tissues were used in this study and divided into the following six groups: controls (Fig.3), free methylene blue (MB) incubation, liposomal MB incubation, laser without MB, free MB for 3 and 4 hrs and laser, liposome MB for 3 hrs and laser. MB was applied to wax epilated areas. The areas were irradiated with CW He-Ne laser system that emits orange-red light with wavelength 632.8 nm and 10 mW at energy density of 5 J/cm2 for 10 minutes. The UV-visible spectrum was collected by Cary spectrophotometer. Results: MB is selectively absorbed by actively growing hair follicles due to its cationic property (Fig.4). MB untreated sections showed that hair follicles and sebaceous glands are intact and there is no change due to the laser exposure (Fig.5). Free MB sections incubated for 3 hrs showed that He:Ne laser induced destruction in hair follicles, leaving an intact epidermis (Fig. 6). Treated section with free MB for 4 hrs showed degeneration and necrosis in hair follicles, leaving an intact epidermis (Fig. 7). Liposomal MB sections incubated for 3 hrs showed He:Ne laser induced destruction in hair follicles with intradermal leukocytic infiltration (Fig. 8). Conclusion: Low power He:Ne laser and MB offers a successful PDT system in selectively damaging hair follicles, leaving an intact epidermis. The current PDT system provides better outcome than hair destruction through laser heat transfer procedures and laser-mediated hair removal, due to complete destruction of hair follicles.
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PCA3 molecular urine test: Development of an easy and cheap assay of a potential use in the diagnosis of prostate cancer.
المؤلفون: Khalid Al-Rumaihi, Jingxuan Shan, Sami Al-Said, Dhanya Kizhakayil, Idil i Aigha, Shoba p Dsouza and Lotfi ChouchaneBackground: The use of the serum prostate-specific antigen (PSA) test for prostate cancer screening has resulted in a diagnostic dilemma: PSA is not prostate cancer specific and could be found in the normal prostate at equal or higher levels than is found in prostate cancer. Prostate cancer gene 3 (PCA3) encodes a prostate-specific mRNA with a median 66-fold up-regulation compared to adjacent benign tissue. In contrast, PSA gene expression is similar in cancerous and benign cells; PSA mRNA levels may therefore be used to normalize for the amount of prostate-specific ribonucleic acid (RNA) in molecular test samples. This report describes the characterization of a prototype quantitative PCA3-based test for whole urine. Methods: First-catch urine specimens were collected after digital rectal examination. The total RNA was isolated with Trizol, amplified, and quantified by use of a real-time PCR method. PSA mRNA concentrations were used to normalize PCA3 signals and confirm the yield of prostate-specific RNA. PCA3 score is calculated by one thousand times of PCA3/PSA mRNA ratio. ROC curve analysis is applied to determine the cutoff value of PCA3 score according to prostate biopsy results. Results: We have collected urine samples of 163 patients from uro-oncology clinic at Hamad Hospital. Due to the mixture of the blood cells and prostate cells in the urine, we failed to obtain RNA with proper quality for 29 samples. The specimen informative rate (fraction of specimens yielding proper RNA for analysis) was 82.2%. From ROC curve with the known diagnostic data, the cut off of PCA3 score is 1232 with a sensitivity of 70% and specificity of 68%. Conclusion: The established PCA3 assay could increase specificity to the current prostate cancer diagnosis. Comparing to the commercial kit, it provides equivalently useful information and it is much cheaper and faster. The challenge is to avoid the interference from the blood cells in the urine.
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Determination of titanium and copper by ICP-MS in rat tissues after oral administration of nanoparticles
المؤلفون: Mohamed A. Amr and Najat AljufairiIn this study, the high sensitive ICP-MS was employed to detect the contents of titanium and copper in liver, lung, spleen, kidney, heart, testis, brain and blood after administering an acute dose of different nano particle sizes of titanium and copper to rats by a syringe via gastrointestinal tract. In coupling with pathological examinations, the target organs of nano- and micro-copper were successfully determined. Biodistribution experiment showed that TiO2 mainly retained in the liver, spleen, kidneys, and lung tissues, which indicated that TiO2 particles could be transported to other tissues and organs after uptake by gastrointestinal tract. Moreover, the target organs of copper nano particles of different sizes after administrating a dose of 100 mg/kg were kidney, liver and blood. Liver is the main damaged organ.
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An innovative thermometric "Stress Test" for early diagnosis of acute charcot
المؤلفون: Bijan Najafi, Gurtej Grewal, Rashad Sayeed, Robert Menzies, Talal Talal, Mahmoud Zirie, Manish Bharara and David ArmstrongBackground & Objectives: Charcot neuroarthropathy (CN) is a devastating complication of diabetes. It has two-fold higher rate of major amputation compared to those without CN. Unfortunately, to date, there is no pathological marker or diagnostic criterion for it and diagnosis relies on pattern recognition and clinical intuition. Not surprisingly, the diagnosis can be missed up to 95% of the time and the average diagnostic delay has been estimated at almost 7 months. Recent studies reported asymmetric plantar temperature differences secondary to inflammation as a hallmark for the diagnosis and treatment response of Charcot foot syndrome. However, little attention has been given to temperature response to activity. Methods: Fifteen individuals with acute CN and 17 age-matched non-CN participants with type 2 diabetes and peripheral neuropathy were recruited. All participants walked for two predefined paths of 50 and 150 steps. A thermal image was acquired at baseline after acclimatization and immediately after each walking trial. The plantar temperature (PT) response as a function of number of steps was examined using a validated wearable sensor technology. A custom image processing toolbox was designed to characterize the plantar temperature response to activity. Results: During initial activity, the PT was reduced in all participants, but the temperature drop for the non-affected foot was 1.9 times greater than the affected side in CN group (p=0.04). Interestingly, the PT in CN was sharply increased after 50 steps for both feet, while no difference was observed in non-CN between 50 and 200 steps. Conclusions: The observed differential thermal response to walking initiation between Charcot and non-Charcot feet warrants future investigation to provide further insight into the correlation between activity dosing and thermal response. It may also lead to a valuable insight into identifying an "inflammatory trigger" that may ultimately provide an early warning sign or increased sensitivity for subsequent unilateral or bilateral CN development or clinical expression of foot ulcer. These results also support that managing modulating duration of continuous steps and or prolonged standing during daily activity could be helpful for reducing the trauma in patients with CN or patients at risk of diabetic foot ulcer.
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Association between obesity, cardiometabolic disease biomarkers and innate immunity-related inflammation: Relevance of vitamin D.
Background and Objectives: Obesity is associated with a state of chronic inflammation and increased cardiometabolic disease risk. The present study examined the relationship between body mass index (BMI) and cardiometabolic and inflammatory biomarkers among normal weight, overweight, and obese subjects. Methods: Subjects (n = 1,805, aged 18 to 79 years) from Canada were examined for associations between BMI, cardiometabolic markers [apolipoprotein (Apo) A1, ApoB, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol, total:HDL-C ratio, triglycerides, and glycosylated hemoglobin (HbA1c)], inflammatory factors [C-reactive protein (CRP), fibrinogen, and homocysteine), and 25-hydroxyvitamin D [25(OH)D]. Bootstrap weights for variance and sampling weights for point estimates were applied to account for the complex survey design. Linear regression models adjusted for age, sex, physical activity, smoking status, and ethnicity (in addition to season of clinic visit for vitamin D analyses only) were used to examine the association between cardiometabolic markers, inflammatory factors, and BMI in adults. Results: All biomarkers were significantly associated with BMI (P≤0.001). ApoA1 (β= 0.31, P<0.0001), HDL-C (β=-0.61, P<0.0001), and 25(OH)D (β=-0.25, P<0.0001) were all inversely associated with BMI, while all other biomarkers showed positive linear associations. Different patterns of significant associations were noted for all biomarkers among normal weight, overweight, and obese groups, excluding CRP which was consistently correlated with BMI and showed a significant positive association in the overall population (β=2.80, P<0.0001) and in the normal weight (β=3.20, P=0.02), overweight (β=3.53, P=0.002) and obese (β=2.22, P=0.0002) groups. Interestingly, plasma vitamin D levels were significantly inversely correlated with BMI (β=-0.25±0.06, P<0.0001). Conclusions: There is a distinctive profile of cardiometabolic and inflammatory biomarkers that emerges with obesity as BMI increases from normal weight to obesity. Elucidating these profiles may permit developing an effective approach for early risk prediction of cardiometabolic disease and its prevention based on modulating the corresponding metabolic phenotype in each BMI stage., e.g., by micronutrients such as vitamin D.
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Cellular senescence as a tumor suppressor mechanism is mediated by sequential activation of the p53 and RB pathways
المؤلفون: Naima Al Mulla, Zafar Nawaz and Raya SaabBackground and Objectives: Oncogene induced senescence is a tumor suppressor mechanism that limits progression of pre-malignant lesions. Identifying the molecular mechanisms by which cells can escape senescence may provide novel cancer therapeutic and preventive targets. Two tumor suppressors, p53 and Rb, are involved in senescence, but their specific roles are still unclear. Our aim is to investigate the role of the Rb and p53 pathways in cellular senescence, to identify mechanisms of cellular escape from senescence, and to evaluate human tumor samples for disruption of the identified pathways. Methods: We are using a transgenic mouse with pineal-cell specific cyclin D1 expression (Irbp-Cyclin D1 mouse). These mice develop premalignant pineal hyperplasia with features of cellular senescence, and tumors progress only when the p53 or the RB pathway is disrupted. Results: We found that p53 was activated early in the senescence response, and led to cell cycle exit. RB activation occurred days later, and coincided with the senescence phenotype that included formation of heterochromatin foci. Disruption of either pathway alone was sufficient for pineal tumor progression. Using genetically engineered mice with regulatable expression of p53, we are now investigating the specific role of p53 in the induction versus maintenance of cell cycle exit. In addition, we are using primary cultures of Irbp-Cyclin D1 pineal cells to examine the effects of turning the p53 and RB pathways "on" and "off" during cellular senescence, to dissect their roles during induction and maintenance of senescence. We are also analyzing premalignant versus malignant tumors from these transgenic mice, to identify recurring genetic lesions that may be important targets for tumor prevention. Finally, we are evaluating human tumor samples for genetic lesions that overlap with the identified pathways. Conclusion: Our preliminary results suggest that the p53 and RB pathways have distinct and complementary effects in the senescence response, where the p53 pathway is important for induction of senescence, while the RB pathway may be responsible for its maintenance. Studies are currently ongoing to verify these observations. These findings will have direct implications on novel approaches to cancer therapy and prevention, by activating cellular senescence and tumor suppression.
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"Ca2+ funneling": Functional coupling between SOCE, SERCA and IP3 receptors enhances Ca2+ signaling efficiency in activating the Ca2+-activated Cl channels as downstream effectors.
المؤلفون: Raphael Courjaret and Khaled MACHACAStore-operated calcium entry (SOCE) is a ubiquitous Ca2+ influx pathway leading to a sustained, low amplitude Ca2+ signal that activates multiple physiological process including gene transcription and secretion, and contributes to store refilling. We here describe a novel mechanism, that we call "Ca2+ funneling", which allows efficient activation by SOCE of Calcium-activated chloride channels (CaCl2) in the xenopus oocyte to regulate the cell's membrane potential. When intracellular Ca2+ stores were emptied using ionomycin, a small CaCl2 current is observed. Conversely, when the stores were depleted following injection of IP3 there was a significantly larger CaCl2 activation than with ionomycin (2.5 ± 0.5 nA, n=14 vs 0.08 ± 0.02 nA, n=20). Surprisingly the size of the SOCE current was similar in both conditions, indicating that an equivalent calcium influx was leading to different CaCl2 activation. Ca2+ injection experiments ruled out any change in the CaCl2 sensitivity to Ca2+. The CaCl2 activated by IP3 could be inhibited by La3+, BTP-2, 2-APB and heparin showing its dependence on both store-operated channels as well as IP3 receptor activation. The same mechanism could also be induced when IP3 production was stimulated by lysophosphatidic acid (LPA). Moreover, we could show that the sustained phase of the biphasic depolarization induced by LPA required SOCE activation. Analysis of the cellular localization of the xenopus TMEM16a (CaCl2) and of the ER calcium sensor STIM1 revealed a tendency of the two proteins to exclude each other following store depletion. We therefore propose the existence of a functional coupling between SOCE, SERCA and IP3 receptors to effectively activate CaCl2 in response to an agonist-induced store depletion. We refer to this coupling as "Ca2+ funneling" where calcium entering the cell through SOCE is rapidly taken up into the ER by SERCAs and released through open IP3 receptors close to its target, the Ca2+-activated Cl channels.
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A pilot study of diagnosed and undiagnosed type 2 diabetic patients in Qatar
Background and Objectives: The prevalence of type 2 diabetes (T2D) in Qatar is the highest in the world. It is estimated that about one quarter of the T2D patients in Qatar are still undiagnosed. We set out to examine determinants of pre-diabetes (PD) or undiagnosed T2D (UT2D). Furthermore, we examined risk factors for glucose regulation in patients with known T2D. Methods: We examined 178 patients with known T2D and 196 controls. Anthropometrics and HbA1c were measured. Socio-demographic (age, gender, ethnicity and educational level) and health information were assessed through questionnaires. Results: Twenty-six (13.3%) and twelve (6.1%) participants in the control group were PD and UT2D, respectively. Control participants from South Asian descent were at a greater risk of being PD or UT2D than Arab controls (Odds Ratio: 5.27 (95% confidence interval: 2.10, 13.22). Being obese was also associated with an increased risk of PD or UT2D (Odds Ratio: 2.94 (95% confidence interval: 1.31, 6.59). Of control participants from South Asian descent, 38% were actually PD or UT2D. In patients with known T2D, insulin use and a longer duration of T2D were both related to higher HbA1c levels (both p<0.0001). No socio-demographic factors were associated with glucose control in T2D. Conclusions: In a nation with a large South Asian immigrant population, we found a strong increased risk of being PD or UT2D in these subjects. Focus should be on the prevention and early identification in South Asian individuals. Larger studies are necessary to further examine the determinants of T2D and glucose regulation in Qatar.
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Metformin regulates hyperglycemia-induced vascular senescence through SIRT1
المؤلفون: Gnanapragasam Arunachalam, Samson M Samuel, Isra Marei, Hong Ding and Chris R TriggleBackground and Objective: Vascular aging is associated with changes in the structure and function of the vascular system and such changes contribute to the risk for the development of diabetes and associated cardiovascular diseases. Vascular senescence reflects the limited ability of vascular cells to divide and proliferate and is accompanied by specific phenotypic changes in morphology, gene expression and function. In endothelial cells, these changes result in a phenotype that is pro-inflammatory and pro-atherosclerotic. The early onset of vascular senescence is also an indicator of premature aging. Recent studies have shown that hyperglycemia-induced vascular senescence is an important contributing factor to promote the development of aging-associated cardiovascular events. Sirtuin 1 (SIRT1) is highly expressed in the vasculature and has recently been identified as an important regulator of endothelial cell senescence-like growth arrest. Metformin is the most frequently prescribed first-line oral hypoglycemic agent for the treatment of type 2 diabetes. Recent studies have demonstrated that the beneficial effects of metformin may be associated, directly or indirectly, with the activation of SIRT1. Methods: In this study, we investigated the molecular mechanisms and protective effects of metformin against high glucose (HG) induced endothelial cell senescence and the contribution of SIRT1-dependent mechanisms. Mouse microvascular endothelial cells (MMECs) were maintained in culture under either normoglycemic (11mM glucose) or hyperglycemic (HG, 40 mM) conditions and Western Immunoblot techniques were used to determine changes in protein expression. Results: Immunoblot analysis reveals that MMECs exposed to HG results in a significant reduction in SIRT1 expression, but an increase in FoxO1 and p53 acetylation. HG exposure also results in a significant up regulation of p21 expression and a decrease in anti-apoptotic Bcl-2 expression. The percentage of senescence-associated β-galactosidase activity is increased with exposure to HG. The presence of metformin reduces the negative effect of HG on SIRT1 expression and protects endothelial cells from HG-induced senescence. Conclusion: These data suggest that HG-induced down-regulation of SIRT1 plays a crucial role in diabetes-associated endothelial cell senescence and, furthermore, that the protective effect of metformin against HG-induced endothelial dysfunction is, at least in part, due to its effects on SIRT1 expression/activity.
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Tunneling nanotubes mediate preferential transfer of mitochondria from endothelial to cancer cells and confer chemoresistance
Many tumors are regulated by complex interactions with cellular components of the microenvironment including mesenchymal stem cells (MSC) or endothelial cells (ECs). While the role of receptor-ligand interaction at the cell surface is well documented, direct cell-to-cell contact has not been clearly established. Recently, tunneling nanotubes (TnTs) have been shown to support cell-to-cell transfer of organelles, various plasma membrane components and cytoplasmic molecules in several cell lines. We thus investigated the formation of TnTs between stromal cells and cancer cells supported by them. We demonstrate that TnTs occur between different cancer and stromal cell lines. TnTs formation seemed to be dependent of large membrane adhesion. We show that intercellular transfers of cytoplasmic content can occur by TnTs. However, we demonstrate that the exchange of mitochondria occurs preferentially between endothelial cells and cancer cells and contributes to chemoresistance. Our results point out the role of direct endothelial to cancer cell exchange, which emphasize our hypothesis that this angiogenesis-independent role of the endothelium plays a role in the constitution of the metastatic niche.
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Biobank Qatar: Implementation and initial results
المؤلفون: Elio Riboli and Paul ElliottBiobank Qatar aims to establish a large national bioresource that will support the development of cutting edge medical research during the next decades. While the design of Biobank Qatar has similarities with other large-scale population-based prospective cohort studies established in other parts of the world, it is unique in the region and excels for its highly innovative scientific and technological features. Biobank Qatar will include up to 80,000 healthy volunteers, who will be followed up during the next decades to investigate the major behavioral, genetic and environmental causes of the chronic diseases most prevalent in the Qatari population. At the initial baseline visit the study participants will provide detailed information on lifestyle and medical history, a number of medical measurements will be made including ECG, spirometry, retinal image, pulse-wave velocity, anthropometric measurements, iDXA etc. Blood, urine and saliva samples will be collected, aliquoted and stored frozen for future investigations. A set of established clinical chemistry analyses (e.g. haematology, lipids, inflammation markers, hormones, nutrients) will be measured at baseline. During 2011-2012, activities focused on the establishment of protocols, clinical and IT facilities. A unique feature of Biobank Qatar is the comprehensive, real-time IT integration of all the baseline measurements. An initial test of the study protocol and clinical measurements was conducted December 2011 to May 2012 when 100 participants attended the biobank facilities at Hamad Medical City. Cooperation of the study participants was excellent. This initial sample provided helpful insights on some lifestyle and medical conditions. For example: - Sedentary lifestyle is highly prevalent. - High prevalence of participants having gained weight in a year. - Diabetics have higher body mass index and larger waist circumference than non-diabetics. - Short sleeping hours are associated with higher blood pressure. - Physical activity, even at modest levels, is associated with lower blood pressure and smaller waist circumference. These initial findings indicate feasibility of high quality data collection, and confirm well-known associations between lifestyle and metabolic features in the Qatari population. The initial test provides strong rationale for the extension of the Biobank to include large numbers of participants as planned.
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Epidemiology of football injuries in Asia: A prospective study in Qatar
المؤلفون: Cristiano Eirale, Abdulaziz Farooq, Faten Smiley, Johannes Tol and Hakim ChalabiObjectives: To investigate the incidence, characteristics and patterns of football injuries at club level in Qatar. Design: Prospective cohort study. Methods: Data were prospectively collected from the first division football league clubs in Qatar, in accordance with the international consensus statement on football injury epidemiology. An injury was defined as any physical complaint sustained during football activity resulting in the inability to participate fully in the next training or match. Individual injuries and exposure of each player were recorded by the medical staff of each team over one season. Results: A total of 217 injuries were recorded, with an injury rate during matches of 14.5/1000 h (95% CI: 11.6-18.0) compared with 4.4/1000 h during training sessions (95% CI: 3.7-5.2). More than one third of all injuries were muscle strains (36.4%). Hamstring strains (54.4% of all muscle strains) exhibited a higher incidence than all other injury types (p < 0.001). The thigh was the most frequent injury location (41.9%, p < 0.001). Re-injuries (15% of total injuries) were mainly comprised of muscle strains associated with a higher severity compared with new injuries. Conclusions: Despite the different environmental, social and cultural setting, our findings are comparable with previous data from a European club football, confirming the previous finding at national team level that there are no regional peculiarities of football injuries in this part of the Asiatic continent. The relatively high overuse injury incidence rate and the high recurrence rate for (severe) thigh muscle strains, especially during games, warrants prevention strategies.
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Evidence for a cell fate refinement mechanism in sensory neurons
المؤلفون: Ishmail Abdus-Saboor and Benjamin ShykindThe olfactory receptors (ORs), which are G-protein coupled receptors, number more than 1,000 and comprise the largest gene family in the mammalian genome. ORs are expressed both monogenically and monoallelically in olfactory sensory neurons (OSNs) and the mechanism that controls their regulation is largely unknown. ORs reside in constitutive heterochromatin and selection of one OR and from one allele occurs stochastically. To ensure singular monoallelic OR expression, a negative feedback mechanism is elicited by the first selected OR to suppress non-selected ORs in a given neuron. Here we describe results for mice with a 'monoclonal' nose that express one OR, M71,in 95% of all mature OSNs. The M71 transgene suppresses expression of endogenous ORs, and remaining endogenous expression is mostly restricted to immature neurons in the olfactory epithelium. We show that the endogenous OR repertoire are expressed prior to suppression by M71 transgene expression, contrary to current models. When we introduced a second transgene into M71 mice that expressed another OR in most mature OSNs, OSNs uncharacteristically expressed both of the ORs. We hypothesize that unresolved OR competition compromised the neuron's ability to express only one receptor. We further show that suppression of endogenous ORs by M71 is not reversible, and that M71 does not need to be continuously expressed for endogenous ORs to remain suppressed. In these experiments, we have engineered OSNs to express more than one OR in an OSN at a time, which is normally a low probability event. We believe that these experiments reveal the existence of a backup pathway that ensures only one OR will be expressed per neuron. It is possible that mammals have evolved similar mechanisms in other examples of stochastic, monoallelic gene expression, such as in random X-chromosome inactivation or lymphocyte receptor expression.
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Bioinformatic parallel processing tools development for mutation identification from whole exome data following homozygosity mapping for autosomal recessive disorders
المؤلفون: Yasser Al-Sarraj, Adel Abouzehry, Hatem El-Shanti and Marios KambourisEight consanguineous Arab families with novel autosomal recessive disorders were mapped with illumina 700K SNP. All relevant positional candidate genes were screened for pathogenic mutations. None were identified. Multiple homozygosity intervals were obtained for each family since no significant LOD scores were possible. Whole exome sequencing was on ABI SOLiD4 for 1 affected individual from each family. Mapping and annotation was on LifeScope software. Data validation was done manually for each linkage interval, by visual inspection of read depth and bead number coverage. On average 30,000 sequence variations were detected in each sample including novel variants, known polymorphisms & exome sequencing errors. For each chromosome with a linkage interval, data was isolated and filtered by exportation to Excel spreadsheets and visual inspection to exclude non-linkage interval data. The number of variants in the linkage intervals for each family was between 400 and 1300. Homozygous sequence variations within the linkage intervals were between 50 and 300 with 15-30 novel variants. Determination if a variant was homozygous or heterozygous, novel or annotated was done manually upon visual inspection of data on Excel spreadsheets. For each novel variant it was manually determined if it were exonic, splice site specific or intronic. For each annotated variation it was manually determined if it is associated to a disease phenotype relevant to the family disease. Minor genotype frequency was investigated for annotated variants if they represent disease states. All novel exonic variants were tested in silico with PolyPhen and Sift Protein Modeling software to access the effect on protein function. All damaging variants (novel or annotated exonic, and splice site) were validated by Sanger sequencing and tested for co-segregation to disease. An identical approach is essential to access pathogenic effects of insertion/deletion variants within each linkage interval. This approach is tedious, involves a tremendous amount of manual work and is prone to oversight errors. Software tools development for automating next-generation sequencing data analysis is essential to eliminate manual work and identify pathogenic mutations among the plethora of existing variants. Such automation is applicable in cases without linkage intervals to limit the number of variants under consideration.
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Novel pyridinium-based cationic lipids as gene delivery vectors
Background: For the past two decades, cationic lipids have remained one of the most widely used non-viral gene delivery vectors due in large to their safety and ease of use despite having low efficiency. We and others believe that the key to improving the effectiveness of non-viral agents is unlocking the still unsolved mechanism behind lipid gene delivery. Our objective is the rational design, synthesis and evaluation of the DNA complexation and in vitro delivery efficiency of novel lipid vectors in an effort to gain structure-function data which may give insight towards the non-viral mechanism. Objectives: Here we report preliminary data on two novel pyridinium-based cationic lipid vectors, designated as TFSA (saturated acyclic structure) and TFUA (unsaturated acyclic structure), both possessing a pyridinium headgroup with a delocalized positive charge, and two saturated (TFSA) or monounsaturated (TFUA) C15 hydrophobic alkyl chains. In the case of the unsaturated analogue, the double bonds are located at the terminal ends of the alkyl chains. Methods: Liposomes were prepared from these novel pyridinium-based cationic lipids in combination with a commercial vector, EPC, together with a co-lipid, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) or cholesterol. Lipid-DNA complexes (lipoplexes) were then formulated by incubating the liposomes with plasmid DNA. Lipoplexes were characterized by gel retardation, DNAse I degradation, as well as biocompatibility and β-galactosidase (β-gal) transfection assays using Chinese Hamster Ovarian (CHO-K1) cells. Fluorescent GFP-plasmid DNA was used to track DNA inside cells using epifluorescence microscopy. Results: The novel lipid formulations were shown to effectively complex DNA and protect it from DNAse I degradation. They were biocompatible with CHO-K1 cells, and performed better when they were formulated with cholesterol over DOPE as co-lipid. Furthermore, the formulation containing the unsaturated compound (TFUA/EPC/DOPE) revealed transfection efficiencies far above TFSA/EPC/DOPE, and superior to the commercial transfection agent EPC formulated alone with DOPE. Results from the GFP-plasmid tracking experiments were consistent with the relative β-gal expressions observed in the transfection assay. Conclusions: These preliminary results suggest that our novel pyridinium-based cationic lipid vectors are effective gene transfer agents, suitable for further investigations into the mechanism of non-viral gene delivery.
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Adipokines as mediators of components of metabolic syndrome in a Qatari population
Background and Objectives: There is a high prevalence of obesity and its co-morbidities within the Arab population, especially in Qatar. Furthermore, the younger age of onset of obesity and its preponderance amongst females have seen an increase in type 2 diabetes and cardiovascular disease in this cohort. Adipose tissue dysfunction preceding frank obesity may underlie the increased risk of metabolic syndrome (MeS). Therefore aims of this study were to characterize the relationship between components of MeS and adipokines in a Qatari population. Methods: Non-diabetic subjects were recruited from the general Qatari population and patients awaiting weight reduction surgery (Al-Emadi Hospital). Lipid profiling and liver function were determined by conventional techniques (HMC). Insulin resistance was measured by HOMA. Adipokines were measured by ELISA. Results: In the whole study population (n=56, 13 males/43 females, 30.5+/-7.5 years old, BMI of 37.5+/-11kg/m-2) significant positive correlations between plasma leptin and BMI were confirmed. However, after controlling for BMI, partial correlations showed that leptin was associated negatively with all measures of blood pressure (all p≤0.01), triglycerides, total- and LDL-cholesterol (all p≤0.01), with liver enzymes (SGPT, AST and Billirubin, p=0.009, p≤0.01 and p=0.02 respectively), and positively with HDL cholesterol (p=0.05). Furthermore, leptin, was also negatively correlated with fasting blood glucose and HOMA (p=0.03 and p=0.01 respectively). In order to investigate this further, the population was dichotomized into age-matched normal weight (n=14) and obese (n=42) sub-groups. The obese group had significantly higher SBP (p=0.006), triglycerides (p=0.03), leptin (p≤0.001) and lower HDL (p≤0.001). Obesity was also associated with deteriorating liver functions manifested as elevation in SGPT (p =0.02), ALP (p= 0.01) and AST (p =0.02). Conclusions: Leptin was elevated in obesity. After correcting for BMI, an inverse relationship between leptin and risk factors for MeS was apparent, suggesting a protective role for leptin in this population, perhaps through its vasodilatory capability. However, when dichotomized into lean and obese groups, chronic elevation in leptin appeared to be associated with increased risk of MeS and deterioration of liver function, as previously described. These novel data are currently being confirmed in a larger ethnicity matched cohort.
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Akt-activated endothelial cells enhance self-renewal, stemness, resistance to therapy, and metastasis in breast cancer
المؤلفون: Pegah Ghiabi, Jennifer Pasquier, Bella Guerrouahen and Arash Rafii TabriziRecently, the role of tumor microenvironment (niche) in regulating cancer progression has been indicated. Tumor microenvironments consists of tumor vasculature, bone marrow mesenchymal stem cells, immune cells and the components of the extracellular matrix. It is believed that the phenotypic advantages acquired by tumor cells are partly the outcome of their interaction with their niche. Endothelial cells are the building blocks of tumor vasculature and have lately been shown to have additional benefits than merely a conduit for supplying oxygen and nutrients. Here, we intend to demonstrate the critical role of the Akt-activated endothelial (E4ORF1) cells on breast cancer development, survival and spreading. The effect of E4ORF1 cells on breast cancer (BC) and breast cancer stem cells (BCSC) self-renewal was assessed by co-cultivating E4ORF1 with MDA-MB231 and MCF-7 BC cells under adherent and suspension conditions. BCSC enrichment by E4ORF1 cells was measured by analyzing the CD44+/CD24Low/- population of BC cells by flow cytometry as well as by evaluating the expression of pluripotency markers by RT-PCR. BCSCs resistance to treatment was investigated by addition of metformin and determining BCSC proliferation with/out E4ORF1. The role of E4ORF1 on BC cell metastasis was shown by migration and adhesion potential of BC cells with/out E4ORF1 cells. Our results demonstrated a 5-fold increase in the self-renewal capacity of BC cells and BCSCs in the presence of E4ORF1. Also, E4ORF1 was able to promote stemness in BC cells as was shown by significant increase in CD44+/CD24Low/- BCSC population and the up-regulation of pluripotency markers. Moreover, BCSCs survived drug treatment by 2.5 folds in the presence of E4ORF1. Besides, BC cells showed enhanced invasion/adhesion property when exposed to E4ORF1 cells. Our data suggest a major role for E4ORFl cells in BC progression, stemness, resistance and metastasis. This characteristic of E4ORF1 cells in maintaining BC cells can be exploited in developing novel anti-cancer therapy to combat BC in a more effective way.
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Identification of molecular pathways implicated in the metastasis process in a mouse model of lung adenocarcinoma
المؤلفون: Mouaadh Abdelkarim, Supria Gerardine, Rufayda Marmar, Omar Kallas, Hamid Massaeli and Nasrin MesaeliA global survey of cancer has shown that lung cancer is the most common cause of the new cancer cases and cancer deaths in both men and women worldiwide. In Qatar a recent retrospective study based on a cohort of patient registry of Al Amal Cancer Hospital from 1991-2006, showed that lung cancer and lumph node cancer are the major cancers in men (5.9%, incident rate per 100,000) while in women breast cancer had the highest incidence. To study the mechanisms of lung cancer development we recently developed a transgenic mouse model overexpressing CRT under the control of Tie2-promotor. The main phenotype of these mice is the development of metastatic lung adenocarcinoma similar to human patients. The objectives of the current study was to identify the molecular pathways involved in the metastatic behavior of lung adenocarcinoma. To examine our objectives we used anchorage independent and adherent culture of lung adenocarcinoma cells isolated from mouse and human cell lines. Using microarray and bioinformatic analysis we have identified several pathways and genes that are altered in mouse cells. The microarray analysis demonstrates that 90 genes are up-regulated and 66 genes are down regulated under anchorage-independent condition compared to adherent conditions. The bioinformatic analyses demonstrate that the up-regulated genes are implicated in cellular development, cellular growth and proliferation pathways. These pathways include: VEGF signaling, bladder cancer signaling, VEGF family ligand-receptor interaction and Ephrin-receptor signaling. The bioinformatic analyses also demonstrate that the downregulated genes were implicated in cell cycle regulation and cell-to-cell signaling and interaction. The analysis of these genes by canonical pathawy demonstrate that these genes are involved in the regulation of very relevant pathaway implicated in cancer essentially : Hematopoeisis from multipotent stem cells, TGF-β signaling and tight junction signaling. We are currently examining these pathways in human adenocarcinoma cell line. In conclusion, our data illustrate that although calreticulin is an endoplasmic reticulum calcium binding chaperone, it is involved in the process of tumor development and metastasis. Further work is needed to decipher the molecular mechanism of involvement of calreticulin in tumor development. This research was funded by QNRF grants UREP09-084-3-016 and NPRP4-043-3-016.
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Epigenetic changes in beta cells related to high glucose
Background & Objectives: Epigenetic changes include two types of changes DNA methylation and Histone modifications. These modifications are influenced by the change in various environmental factors resulting in a stable form of gene expression changes. Type II Diabetes incidence keeps rising with so little understanding of the actual cause at gene expression level despite the massive amount of research around the subject. Which is why we chose to capture a closer image of what happens at the genome level when environmental factors such as high glucose intake can influence healthy cells into change their gene expression to adapt and how is that related to Diabetes. Methods: Mouse Beta cells are grown for several generations at various glucose concentrations in two groups, each group consisting of three biological replicates, each replica of glucose concentration (High vs. Normal) is devoted for one histone modification marker (H3K4me2, H3K27me2). The treated cells are further processed by chromatin-immuoprecipitation followed by next generation Sequencing (ChIP-Seq). Results: Data analysis was performed to identify enriched affected pathways. Significant differences in gene expression between high levels of glucose versus normal glucose were found using ChIP-Seq and confirming what was previously obtained by ChIP on Chip. Conclusion: The results of this experiment shed some light on the matter of surrounding environment effect on gene expression. Evidence of environmental elements affecting blood glucose levels was seen predecting difference in gene expression, e.g. type II diabetes risk factors. Genes involved in several pathways showing evidence of cardiac muscle diseases, kidney damage and changes in the calcium channel signaling were observed, all of which are related to type II diabetes complications.
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The relative risk of road mortality (RRRM) in Qatar
المؤلفون: Rafael Consunji, Ruben Rosario Peralta, Hassan Al Thani and Rifat LatifiBackground and Objectives: The epidemiology of road deaths in Qatar has not been fully described. This study will analyze and compare the age-specific death rates from motor vehicle crashes (MVC's) and make recommendations for targeted injury prevention programs for road safety in Qatar. Method: Data from the Qatar Statistic Authority (QSA), for the year 2010 was collected and analyzed. All deaths classified as "motor- or nonmotor-vehicle accident, type of vehicle unspecified" were included. Age group populations were computed from age-specific crude death rates. Results: There were 247 MVC deaths in Qatar in 2010. An overall death rate was computed at 14.2 deaths per 100,000 population. The RRRM varied over ten times amongst different populations with Qatari males (QM) having an increased RRRM from 10 years of age. The QM's aged 20-29 had the highest RRRM of 10.2. The lowest RRRM was for Qatari females who did not have a single road fatality in 2010. Other populations with elevated RRRM (i.e. RRRM >1.0) were non-Qatari males ages 10 to 19 and older than 50 years. Conclusions: Qatari males have an elevated RRRM from the age of 10 onward, definite programs must be implemented to reduce these unnecessary deaths amongst the populations at the highest risk. Multidisciplinary approaches must be implemented and their efficacy evaluated.
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Inhibition of NFκB signaling in calreticulin deficient cells
المؤلفون: Hamid Massaeli, Divya Viswanathan, Aleksandra Liberska, Kawathar AlDabhani and Nasrin MesaeliCalreticulin (CRT) is an endoplasmic reticulum (ER) Ca²+ binding chaperone, which regulates many of cellular processes. Previous work from our lab showed loss of CRT leads to increased resistance to apoptosis. We also showed loss of CRT leads to increased AKT phosphorylation and activation of the proteosome activity. Thus we hypothesized that in the absence of CRT function, NFκB signaling is activated leading to enhanced resistance to apoptosis of these cells. Wild type and CRT knockout mouse embryonic fibroblast were used to examine changes in the NFκB signaling pathway. Reporter gene assays showed a significant reduction in the basal NFκB transcriptional activity. Activation of NFκB with lipopolysaccharide increased the transcriptional activity of NFκB in both the cells, however, the transcriptional activity of NFκB was still significantly lower in the CRT deficient cells as compared to the wild type cells. Our immunocytochemical staining showed a delay in the translocation of NFκB p65 to the nucleus of CRT deficient cells after lipopolysaccharide treatment. We also observed an increase in the level of IκB and phospho-IκB accumulation in CRT deficient cells after lipopolysaccharide treatment. We conclude that in the absence of CRT NFκB signaling is inhibited due to decreased IκB degradation and decreased NFκB p65 nuclear translocation.
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SID-MRM-MS enabled verification of biomarkers of type 2 diabetes in a Qatari population
المؤلفون: Prabhjit Kaur, Nasser M Rizk, Noura Younes, Mahmoud Zirie and Amrita K CheemaBackground and Objectives: Recent technological advancements in liquid chromatography coupled with high resolution mass spectrometry have facilitated clinical biomarker discovery, verification and validation. Targeted metabolic profiling refers to the precise quantitative measurements of metabolites for validation of markers identified via untargeted metabolomics. Specifically, multiple reaction monitoring mass spectrometry has enabled the reliable quantification of biomarkers in hundreds of samples, in a multiplexed manner. Methods: In this clinical study we have employed SID-MRM-MS (stable isotope dilution - multiple reaction monitoring - mass spectrometry) to quantify different classes of endogenous metabolites including intermediates of TCA cycle and lipids, on a triple quadrupole mass spectrometer. NPRP funded project enabled us to recruit a total of 169 controls and T2DM (type 2 diabetes mellitus) patients at the Hamad Medical Corporation in Doha, Qatar. Based on the discovery mode metabolomics profiling experiments, ten target molecules were chosen for biomarker validation using a cohort of 72 (control and diabetic) urine and plasma samples spiked with a known concentration of stable isotope labeled standard for each metabolite. The normalized peak area ratios were used to calculate the levels of deregulated metabolites in the T2DM cohort. We also performed extensive quality control experiments to check for retention time variation, matrix effects and metabolite degradation during sample processing. Statistical analysis was performed using GraphPad Prism (v5.0). ROC curves and interactive plots with a stringency cut-off of P ≤0.05 were plotted to test biomarker specificity and sensitivity. The cut-off values were selected to maximize the Youden index. Results: Statistically significant downregulation of succinate, xanthurenic acid, α-ketoglutaric acid and kynurenic acid were observed in the T2DM group while the concentrations of serotonin, PG (18:0/18:1), PC, sphingosine-1-phosphate and pyruvate were determined to be significantly higher in the diabetic group. The OPLS-DA model for the target metabolites had two orthogonal components and the R2 and Q2 were 0.88 and 0.87 respectively. Conclusions Our results underscore the clinical and translational utility of the MRM-MS approach. Further validation and characterization with larger cohorts, is likely to provide valuable insights into clinical potential of these markers and their correlation with T2DM associated complications.
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Fuzzy-QFD approach to quality assurance in pediatric services in public and private hospitals in Qatar
المؤلفون: Hana Yousef Al-Shouli and Mohd Nishat FaisalBackground and objectives: This study was conducted to understand the dimensions important for quality assurance in pediatric services of public and private hospitals in Qatar. Method: The study employed Fuzzy- Quality Function Development (Fuzzy-QFD) approach to translate the patients expectations into appropriate service specifications and to perform assessments of the existing processes. The importance of this tool lies in its ability to improve customer satisfaction levels since its major role is the alignment of technical requirements on the basis of customer demands. In this study, patients who visited pediatric services were surveyed about their expectations from pediatric hospitals to develop the "WHAT" part of the Fuzzy-QFD model. Then a focus group consisting of three doctors, a nurse and one healthcare researcher was formed to identify appropriate service specifications and the existing processes available in pediatric hospitals in Qatar. The input from this group was used to develop the correlation matrix, which was an important step in the Fuzzy-QFD process. The matrix showing the relationship between the "WHAT's" and the "HOW's" seeks to match patients' expectations with the technical specifications of the services adopted by the hospitals. Results and conclusions: The final weight and ranking concluded that management should give prime importance to 1) continual survey of patients to assess their needs, 2) patients and family rights, 3) the quality of policy and procedures documentation, 4) in-service continuous education and training, 5) the management of nursing operations, 6) the Service Quality Program (quality and patient safety), and 7) the waiting and distribution systems.
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Targeting microRNAs offers a new therapeutic approach for the treatment of diabetes-related cardiovascular disease
المؤلفون: Hala Omar, Isra Marei, Gnanapragasam Arunachalam, Samson M. Samuel, Christopher Triggle and Hong DingBackground and Objectives: The World Health Organization states that cardiovascular disease is the leading cause of death worldwide. The increasing prevalence of obesity and diabetes indicate that cardiovascular disease will remain a major health concerns for decades to come. The Gulf States including Qatar, the Middle East and the North African (MENA) region as whole, but also elsewhere in the world, face a pandemic of obesity and diabetes. Hyperglycaemia is the common denominator of both type-1 and type-2 diabetes and results in "glucose toxicity" that is closely linked to the high cardiovascular morbidity and mortality associated with diabetes. A reduction in the generation of NO -an important contributor to the endothelium regulation of blood flow and coagulation- in response to hyperglycaemia, is an early indicator of the onset of vascular disease. NO bioavailability is determined through the balance of its generation by eNOS and its quenching by reactive oxygen species, ROS. In response to hyperglycaemia and a variety of metabolic perturbations, eNOS produces predominately superoxide anions rather than NO and there is therefore an increase in oxidative stress and reduced bioactivity of NO. MicroRNAs (miRs) are small non-coding RNAs that inhibit gene expression and have also been implicated in the regulation of endothelial cell biology. A number of miRs including 221 & 222 have been implicated in endothelial cell function. They are involved in post-transcriptional control of major regulatory pathways. Methods: Mouse microvascular endothelial cells (MMECs) were cultured in normal (11mM) or high glucose (HG, 40mM) media and the ratio of coupled (dimeric) to uncoupled (monomeric) eNOS determined by immunoblot. ROS, NO and the expression of miR-221/miR-222 were also measured. Results: HG enhanced ROS, reduced the eNOS dimer/monomer ratio and reduced the generation of NO. Our data indicate that HG-induced ROS generation can be reversed in the presence of inhibitors of miR-221/miR-222. Conclusion: Hyperglycemia is associated with increased oxidative stress and decreased NO bioavailability. miR-221 and miR-222 play an important role in high glucose-induced increased oxidative stress and endothelial dysfunction.
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Relationships between anthropometric factors and repeated-sprint ability in the Qatar national soccer team
Background & Objectives: Muscle mass is a major determinant of power development during maximal sprinting. The ability to recover and subsequently reproduce high-intensity efforts (termed repeated-sprint ability, RSA) is closely related to match-performance in soccer. The aim of this study is to assess any relationship between anthropometric parameters and RSA performance in a national soccer team in the Middle East. Method: Sixteen members of the senior male Qatar national soccer team performed six 35-m maximal running sprints on grass departing every 10-second. Sprint times, acceleration (Accbest and Accmean), velocity and peak (PP) and mean (MP) power were calculated. Power results were also adjusted to body mass. To assess RSA, total time and sprint decrement (Sdec) score were calculated. Anthropometric measures (e.g. breadths, girths, skinfolds) and derived factors (e.g. body composition, proportionality) were assessed according to the standard of the International Society for the Advancement of Kinanthropometry. Pearson's product-moment correlations were conducted. Results: Significant (p<0.05) relationships occurred between muscle-to-bone ratio and all RSA variables (r < -0.53 for sprint times and all r > 0.51 for Accmean, velocity and power scores) with the exception of Accbest and Sdec. Muscle index, cross-sectional area for mid-thigh and calf muscle groups were only correlated (p<0.05) with PP (r = 0.70, 0.73 and 0.60, respectively) and MP (r = 0.63, 0.73 and 0.62 respectively). The sum of 6 skinfolds and adipose index were positively correlated with Sdec (r = 0.68 and 0.55, respectively; p < 0.05). Conclusion: In the Qatar national soccer team players' RSA is associated with a high muscular profile and a low adiposity. Such observation would be of benefit with the purpose of providing training and nutritional recommendations to improve match-related performance in soccer.
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Point prevalence survey of antibiotic utilization in oncology patients
المؤلفون: Sara Hayder Ahmed, Arwa Hammuda, Emily Kathleen Black and Shereen ElAzzazyBackground & Objectives Point Prevalence Surveys (PPS) are used internationally for identifying antibiotic prescribing practices and evaluating antibiotic stewardship programs. The objectives of this study are to develop a PPS tool to be used in Qatar, to determine prevalence of antibiotic consumption in the National Center for Cancer Care and Research (NCCCR) inpatient population, and to characterize antibiotic prescribing practices. The secondary goal is to identify targets for antibiotic stewardship programs to improve prescribing practices. Methods A chart audit tool was designed based on the available literature and piloted for face validity. All adult inpatients receiving active systemic antibiotic prescriptions at 8:00AM on each audit day were surveyed. Data were collected on 3 separate days over a two week period from 26 April through 3 May 2012 at NCCCR. Collected data obtained from electronic and paper-based charts included: diagnosis, type, dose and frequency of antibiotics, route of administration, and duration of therapy. Further information such as compliance to the available local guidelines and microbiology results were also assessed. Results The overall prevalence of antibiotic use during the audit was 43% (25/58). A total of 33 antibiotics were prescribed to the 25 patients receiving systemic antibiotic therapy. An indication for antibiotic prescribing was documented in 80% (20/25) of patient charts, however, only 20% (5/25) reported duration of antibiotic therapy. The most frequently used antibiotics were Penicillin/β-lactamase inhibitor combinations 40% (13/33), followed by carbapenems 15% (5/33). In 2 out of 6 febrile neutropenic patients, local febrile neutropenia guideline was accurately implemented. Sixty one percent (20/33) of prescriptions complied with local antibiotic restriction guideline. Pre-therapy cultures were performed for 96% (24/25) of patients and all antibiotic choices matched results of available sensitivity tests performed for these patients. Conclusions The findings of this study demonstrate frequent antibiotic consumption in the immunocompromised population highlighting the importance of development, implementation, and expansion of antibiotic stewardship programs at NCCCR.
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The effect of graded hypoxia on the development of neuromuscular fatigue during maximal intermittent dynamic leg extensions
المؤلفون: Ryan Christian, Olivier Girard, Francois Billaut and David BishopHypoxia has been shown to exacerbate the performance loss during Maximal Intensity Intermittent Exercise (MIIE). However, the effect of hypoxia on the development of central and peripheral mechanisms of fatigue during MIIE is unknown. The aim of the study is to explore the development of both central and peripheral fatigue during multiple bouts of MIIE under varying severity levels of hypoxia. On separate days, 14 healthy men performed four bouts of 6 x 5 maximal intensity, isokinetic leg extensions at 300°/s (15 s passive rest separating reps, 100 s separating sets) under normoxia (simulated altitude/fraction of inspired 02: 0m/0.21%), moderate (3000m/14.4%), and severe hypoxia (5400m/10.1%). Neuromuscular assessments which included electromyography and measurements of voluntary and evoked contractions of the knee extensors were conducted immediately pre and post each bout of exercise. Performance loss was dependent on the severity of hypoxia with a main effect of condition on the mean peak power during each bout of exercise (p<.005) and the percent decrement in mean peak power across each bout (normoxia; 2.9 ± 1.3 %, moderate hypoxia; 5.2 ± 1.5 %, severe hypoxia; 10.3 ± 2.0 %, p=<.01). Despite a main effect of time, the reduction in RMS activity was not different between conditions (-10.4% all conditions compounded). Maximal voluntary contraction force, % voluntary activation and potential twitch force (Q,tw,pot) all decreased across time (p=<.05), with the end exercise percent reduction in Q,tw,pot being greater in severe hypoxia compared to normoxia (41.3 ± 3.0 % v 28.0 ± 3.2 % p=<.05). In conclusion, performance decrements during maximal intermittent dynamic leg extensions are exacerbated by hypoxia and result from both central and peripheral adjustments. However, central adjustments do not appear to limit excessive development of peripheral fatigue below a critical threshold.
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Effects of lipotoxicity and diabetes on hepatocyte function
المؤلفون: Alhasan Sedeeq, Mohamed Al Hajri, Mennatallah Omar, Isra Marei, Christopher Triggle and Hong DingBackground and Objectives: Obesity is a major risk factor for the development of liver disease and diabetes and there is currently a pandemic of diabetes that is associated with a very high incidence of non-alcoholic fatty liver disease and consequent deregulation of liver function. The overall objective of this project is to determine whether non-alcoholic fatty liver disease and hyperglycemia affect calcium homeostasis via altering the expression of the plasma membrane calcium release-activated calcium channel protein, Orai1, the endoplasmic reticulum calcium sensor protein, STIM1, and store-operated Ca2+ entry, SOCE, in rat hepatocytes. Methods: Rat H4IIE liver cells exposed to amiodarone were used as a cell culture model of steatosis and Western Blot, RT-PCR and fura-2 techniques were used to assess protein, mRNA and changes in Ca2+ homeostasis, respectively. Rat H4IIE liver cells were grown either in normal glucose (5.5 mM) or high glucose (25 mM) for 24 hours, then each group was treated with either vehicle (methanol), amiodarone for 24 hours, or amiodarone for 24 hours followed by normal glucose for another 24 hours. Intracellular calcium [Ca2+]i was measured using fura-2am. Results: Expression of both STIM1 and Oai1 increases after treating with amiodarone for 24 hours in both normal and high glucose, but decreases after treating with amiodarone for 24 hours when followed by normal glucose treatment. In addition high glucose enhances SOCE whereas amiodarone treatment suppresses SOCE. Conclusion: Changes in the concentration of intracellular Ca2+ in hepatocytes play a central role in mediating the actions of insulin, glucagon, catecholamines and other hormones and growth factors on carbohydrate, lipid and protein metabolism in the liver. Both hyperglycemia and steatosis result in alterations in Ca2+ homeostasis suggesting that such changes may be contributing factors by which hyperglycemia, obesity and fatty liver result in insulin resistance in the liver. The results from this UREP project may lead to a better understanding of the mechanisms whereby diabetes, obesity and fatty liver disease result in liver malfunction.
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