Qatar Foundation Annual Research Forum Volume 2011 Issue 1
- تاريخ المؤتمر: 20-22 Nov 2011
- الموقع: Qatar National Convention Center (QNCC), Doha, Qatar
- رقم المجلد: 2011
- المنشور: ٢٠ نوفمبر ٢٠١١
51 - 100 of 281 نتائج
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Proportionate Mortality and Relative Risk from Motor Vehicle Crashes in Qatar: a Tool for Prioritizing Preventive Programs & Research
المؤلفون: Rafael ConsunjiAbstractBackground: Motor vehicle crashes (MVC's) are a recognized public health problem in Qatar, where they are a leading cause of death. Given the diverse population in Qatar there is a need for evidence to identify high-risk populations bearing a disproportionate MVC mortality burden.
Objective: To identify the populations at the greatest risk for death from MVC's in Qatar, by measuring proportionate mortality (PMMVC) and relative risk (RRMVC).
Methods: An analysis of published mortality and population data was conducted to calculate for PMMVC and RRMVC and identify high-risk populations at a disproportionate risk for MVC mortality.
Results: One in seven (13.9%) deaths in Qatar is due to an MVC. Males are the victim in 90% of MVC deaths, with PMMVC > 30% from 5–29 years. One-half (51%) of all deaths in the 10–19 age group are due to MVC's, with the highest PMMVC for Qatari males (QM) aged 20–29 and for Non-Qatari males (NQM) aged 10–19. MVC's were the leading cause of death for QM's ages 5–39, Non-Qatari females (NQF's) ages 10–19, Qatari females (QF's) and NQM's ages 5–29. The highest RRMVC in the general population was for females ages 5–9 and males ages 10–19. The highest RRMVC is for QF's and QM's ages 20–29. NQF's also have a higher RRMVC than QM's for ages 10–19. The oldest and youngest populations had protective RRMVC's. QM's have more than double the RRMVC, compared to the general population, from ages 5–39 and Qatari females (QF's) extend this risk till the age of 49. NQF's share this elevated risk profile [RRMVC>2] with QF's while NQM's are most at risk from 5–29 years.
Conclusion: MVC's are the leading killer of the largest segment of the population of Qatar, those ages 5–29. Young males [10–29 years] bear a disproportionate PMMVC but females have a higher RRMVC. An elevated RRMVC starts at 5 years and continues till 29 years. A commensurate response in the form of targeted interventions to reduce MVC deaths and research to identify and reduce risk factors amongst the populations with the highest MVC risk and burden should be prioritized.
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Evidence for Renal Lipid Accumulation, Impaired Mitochondrial Fatty Acid Oxidation and ER Stress in the Development of Renal Dysfunction Induced by Obesity
المؤلفون: Shankar Munusamy, Jussara M do Carmo, Jonathan P Hosler and John E HallAbstractObesity is a global epidemic and has been implicated as a risk factor for end-stage renal disease. In this study, we investigated the impact of obesity in the absence of hypertension, on renal lipid accumulation, oxidative stress, mitochondrial function, and endoplasmic reticulum (ER) stress, which could play a major role in the development of obesity-induced renal dysfunction. We compared two genetic mouse models of obesity which we have shown to be normotensive, the leptin-deficient ob/ob mice and a hyperleptinemic melanocortin 4 receptor knockout mice (LoxTB MC4R-/-), to lean wild type (WT) C57BL/6J mice and littermate controls (WT-LoxTB) from LoxTB MC4R-/-breeding colony respectively. We measured urinary albumin excretion, creatinine clearance, renal triglycerides, ATP levels, state-3 mitochondrial respiration, protein carbonylation (a marker of oxidative stress) and C/EBP homologous protein (CHOP) expression (a marker of ER stress) in these mice. Our results indicate that the ob/ob mice and LoxTB MC4R-/-mice exhibit significant albuminuria, increased creatinine clearance (693±61.1 vs. 534±31.5 and 752.3±50.6 vs. 488.9±81.2 μL/min) and renal triglyceride accumulation (8.1±0.8 vs. 4.8±0.2 and 3.9±0.5 vs. 2.2±0.3 mg triglyceride/g tissue) expressed as ob/ob vs. WT and LoxTB MC4R-/- vs. WT-LoxTB respectively. Despite significant decreases in renal ATP levels (6±0.3 vs. 7.9±0.4 and 5±0.2 vs. 8±1.1 pmol/mg) in both obese models, only the LoxTB MC4R-/-mice kidneys showed an impaired state-3 fatty acid oxidation, increased protein carbonylation and 3-fold induction of CHOP protein compared to WT-LoxTB control mice. Taken together, our data suggest that obesity in the absence of hypertension cause only mild renal dysfunction, and unveils the potential involvement of oxidative stress, impaired fatty acid oxidation and ER stress in obesity-induced renal injury associated with MC4R deficiency.
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ChIP-chip Investigation of Epigenetic Changes in Response to Various Glucose Environments
المؤلفون: Yasmeen Salamah, Moneera Al-Jaber, Eman Al-Azwani, Eman Al-Odus, Binu George and Joel A. MalekAbstractWith the rise in incidences of Diabetes within the Middle East, it will be important to understand the environmental and genetic components of the disease. Epigenetic changes, including DNA methylation and Histone modifications, can be a response to environmental signals resulting in stable gene expression changes. To begin understanding the epigenetic effects of glucose in the diet we conducted Chromatin Immunoprecipitation followed by tiling array (ChIP-chip) analysis on in vitro cultures of cells grown in varying amounts of glucose. We have investigated the effects on DNA methylation and various Histone methylation levels. Results from this study are presented. Initial results from this study will guide more detailed analysis of the progress of epigenetic changes, their stability, and their possible transmission to future generations.
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Arsenic/Interferon Combination: A Novel Therapeutic Approach to Target CML Stem Cells
المؤلفون: Rihab Nasr, Ahmad Iskandarani, Jessica Saliba, Rabab El Eit, Hanadi Elayoubi, Hugues de The and Ali BazarbachiAbstractImatinib is currently the standard drug used in the treatment of CML patients. However, imatinib is not curative since most patients who discontinue therapy will relapse. Interferon alpha (IFN) induces hematologic and cytogenetic remissions and interestingly, prior exposure to IFN allowed Imatinib discontinuation in some CML patients. Arsenic trioxide inhibits the proliferation of BCR-ABL-expressing cells.
We have investigated the effects of the combination arsenic/IFN on the proliferation of CML cell lines. We found that IFN alone had minimal effect. Arsenic alone significantly decreased their proliferation in a time and dose-dependent manner. Interestingly, the addition of IFN to arsenic was synergistic in AR230 and additive in K562. This synergistic effect between IFN and arsenic was accompanied by dose-dependent apoptosis as evidenced by annexin V staining, TUNEL positivity and caspase activation. Colony-forming assay was performed on bone marrow and CD34+ cells collected from CML patients. Interestingly, arsenic and IFN produced a synergistic decrease in myeloid colony formation, especially when compared to Imatinib.
Preliminary results of an in vivo study using the retroviral transduction CML mouse model showed prolonged survival of secondary recipients that received cells from primary leukemic mice treated with arsenic/IFN, as compared to those that received cells from untreated controls. These results suggest that arsenic and IFN synergize to inhibit proliferation, induce apoptosis and target dormant CML stem cells that are spared by Imatinib.
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Detection of Early Infection with Flu Viruses in Patients with Bronchial Asthma and COPD in Winter Season in the State of Qatar
المؤلفون: Asma Al-ThaniAbstractFlu infections are viral infections of the upper and lower respiratory tract which are an important cause of morbidity in patients with bronchial asthma, chronic obstructive pulmonary disease (COPD), old age and other chronic medical conditions, usually occur in outbreaks mainly during the winter season, and require inpatient and outpatient care. Objectives: 1) understanding the viral etiologies of respiratory tract infection among patients who presented to chest clinic during the winter season from first October 2008-31 March 2009 with the diagnosis of asthma and/or COPD. 2) While Hamad Medical Corporation laboratory uses Immune Fluorescent Assay (IFA) to test for five viruses: Respiratory syncytial virus (RSV), influenza A & B virus, Para-influenza virus and Adenovirus, an objective of this study was to develop and evaluate a new diagnostic test using Real-time PCR to detect 15 viruses simultaneously. Those are: Flu A&B; Corona viruses (Cor63, 229 & 43), Parainfluenza viruses (para1,2,3&4), Human metapneumovirus (Hump A and B), Rhinovirus (rhino), RSV(A & B) and adenovirus (AV)). Methods: Nasal swabs were collected (to detect upper respiratory viruses). Patient's personal data as well as diagnosis and medical history were gathered using questionnaires filled by the doctor treating the patients at the time of the nasal swab. These questionnaires were analyzed using SPSS V.14. Results: The sample size consisted of 200 patients, 18 years of age or older, with asthma and/or COPD. Out of the 200 patients, 190 had asthma and 10 had COPD. However, only 36 patients had viruses related to respiratory tract infection; 31 of which had asthma and 5 had COPD. It was found that the Rhino viruses are the most predominant respiratory viruses. Additionally, using Real-time PCR enabled the detection of more than five viruses at the same time with similar sensitivity and specificity when compared to the Immune Fluorescent Assay.
Conclusions: To our knowledge, this is the first report of respiratory tract viral infections from Qatar. Detection of these infections may have significant clinical implications in the study population. Additionally, it was found that the new diaginostic-respiratory detection by real-time PCR technique was able to detect more than five viruses at the same time compared with the (IFA) with similar sensitivity and specificity.
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The Effects of Heat Exposure on Cognitive Performance
المؤلفون: Nadia GaouaAbstractIn addition to physical conditioning, successful sporting performance requires a level of perception coupled with efficiency and accuracy in movement. The FIFA World Cup is usually played during the summer months; therefore the aim of this study was to investigate the effects of heat exposure on cognitive performance.
Three experiments were performed in an environmental chamber under hot (HOT: 50°C, 30% rH) and control (CON: 24°C, 30% rH) conditions. Exposure time ranged from 15 minutes to 4.5 hours. Subjects performed simple and complex cognitive tasks under different levels of thermal strain. Neuromuscular assessments were performed to assess neural drive and muscular force production. Central (Tcore) and skin (Tskin) temperatures were recorded along with subjective measures of thermal comfort (TC) and thermal sensation (TS).
Hyperthermia had no impact upon attention tasks, however, impulsivity increased during sustained attention over prolonged periods. Significant increases in Tcore (>38.30°C) were associated with impaired complex cognitive task performance. The regular application of cold packs to the head limited the detrimental effects of hyperthermia upon short-term memory. However, rapid and substantial variations in Tskin of ∼3°C, independent of changes in Tcore, had similar detrimental effects upon cognitive task performance.
Results suggest that reductions in complex cognitive performance with heat exposure occur via a decrement in motor cortical excitability when Tcore increases to ∼38.3°C, but they also originate from an additional cognitive load imposed by thermal strain and the resulting allesthesial Tskin variations; with both these factors acting as competing variables to the cognitive processes.
The increase in Tcore with prolonged heat exposure impairs cognitive performance; however applying cold packs to the head can preserve these. Increases in Tskin during brief heat exposures appear to be a sufficient physiological response to alter the emotional state of individuals and impair effective decision-making. Hydration protocols and reducing exercise intensity and load can reduce the physiological strain. Strategies to minimise the ‘thermal shock’ of entering a warm environment should be developed to minimise the impact of subjective feelings of thermal discomfort upon cognitive performance.
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The Development of an Athletic Performance Predictive Genetic Test
المؤلفون: Vasiliki Chini and Hatem El-ShantiAbstractBackground: Genetic factors play an important role in the performance of athletes. There are known gene variations that contribute to athletic endurance or muscle performance, while other variations influence the susceptibility to injuries or Body Mass Index (BMI).
Objectives: The aim of this project is to develop a comprehensive molecular genetic predictive test which, employs the analysis of multiple specific gene variations and can be applied to young children to assist in the choice of the appropriate sport and the preparation of an athlete.
Methods: 31 single nucleotide polymorphisms (SNP) clustered in24 genes and known to be associated with athletic performance were selected. The genotyping is by Real-Time Polymerase Chain Reaction (RT-PCR) using TaqMan assay technology with probe and multiple primer chemistry. This was applied to 10 anonymous DNA samples to assess the adequacy of the test and to choose controls for future sample genotyping. Genotypes were validated by direct resequencing.
Results: Genotypes were generated for 31 SNPs for the 10 DNA samples and validated by resequencing. All RT-PCR results (repeated twice for confirmation) were consistent with the resequencing results.
Conclusions: We have developed a panel of 31 SNPs reported in the literature to play a role in athletic ability and performance. The panel serves as battery for predictive tests that can predict susceptibility to injuries, as well. The genotyping can be done in mass and the genotyping of the whole panel is cost permissive. This test can be applied to young promising athletes to guide in the choice of the sport and in their preparation and training. Furthermore, the panel can be utilized to guide older athletes, to improve their training and avoid injuries.
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Cisplatin's Modulation of Intracellular Calcium Concentration is Related to the Viability of the Breast Cancer Cells, MCF-7
المؤلفون: Nawaf Al-Taweel, Elizabeth Varghese and Dietrich BüsselbergAbstractBackground: Cisplatin (cis-diamminedichloroplatinum (II), CDDP) is a highly effective antitumor drug. However, tumors can acquire resistance to CDDP. CDDP elevates the intracellular calcium concentration ([Ca2+]i), in various cell lines, leading to the activation of apoptotic pathways and cell death. Using cultured breast cancer (MCF-7) cells we: (1) investigated the effects of CDDP on [Ca2+]i, (2) compared these results to a cell line that has been desensitized to CDDP (“resistant”), (3) investigated the source of [Ca2+]i by modulating calcium channels and transport mechanisms, and (4) correlated these findings to cytotoxicity. Methods: Changes in the [Ca2+]i were recorded using fluorescence microscopy and Ca2+-binding fluorescent dye, Fluo-4AM. CDDP (1nM-10μM) was administered via a bath perfusion system to the sensitive and CDDP-”resistant” MCF-7 cells over a period of 1.5–2.5h. The [Ca2+]i modulators, (caffeine; 10mM, nimodipine; 10μM, ionomycin; 10μM, thapsigargin; 500nM, and 2-APB; 50μM) were administered. MTT assays and trypan blue cell viability tests were performed using CDDP at concentrations of 100pM, 1nM, 10nM, 100nM, 1μM, 10μM, 100μM, 1mM, and 10mM after 4, 8, and 24h of incubation. Results: CDDP induced a concentration-dependent increase of [Ca2+i. A concentration of CDDP 0.1μM triggered the largest elevation of [Ca2+]i with 120% increase (n=19). Induction of cytotoxicity was most likely directly correlated to the increase of [Ca2+]i, and was significantly lower in CDDP-”resistant” cells (P←0.05). Preapplication of the calcium channel blocker, nimodipine as well as the IP3 receptor blocker 2-APB significantly reduced this elevation (46.6%; n=26, 71.4%; n=52, increase, respectively) (p←0.05). Surprisingly, when [Ca2+]i was elevated due to the pre-application of caffeine, ionomycin or thapsigargin, the subsequent application of CDDP was also significantly reduced compared to control conditions (37.8%; n=15, 34.9%; n=32, 53.7%; n=21, increase, respectively) (p←0.05). Conclusion: CDDP concentration-dependently elevates [Ca2+]i by Ca2+ entry and Ca2+ release from the stores. These mechanisms, however, seem to be less effective in CDDP-”resistant” cells since they show increased restriction on Ca2+ elevation. The pre-elevation of [Ca2+]i, through releasing Ca2+ from the stores, reduces this elevation significantly. The exact mechanisms remain unclear and further investigations are required to determine the mechanisms and pathways that are involved in the disruption of [Ca2+]i.
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STIM1 Function in Mitosis and Meiosis
المؤلفون: Rashmi Kulkarni, Johannes Graumann and Khaled MachacaAbstractThe endoplasmic reticulum (ER) functions as a storehouse for intracellular Calcium. STIM1, a Calcium sensor localizes mostly to the ER membrane in interphase under resting conditions. Following Ca2+ store depletion, STIM1 forms puncta that localize to the cortical ER and binds Orai1, a Ca2+ channel to allow Ca2+ influx. This mechanism of Ca2+ influx is termed Store-Operated Calcium Entry (SOCE). Orai1 is internalized during meiosis and STIM1 fails to aggregate even when intracellular Ca2+ stores are depleted in both mitosis and meiosis. This causes inhibition of SOCE during mitosis and meiosis. This is an important mechanism to prevent sporadic Ca2+ influx that could disrupt its specialized functions during the cell cycle. We are interested in elucidating the mechanisms that allow STIM1 to cluster during interphase but not during M-phase.
We have taken a proteomics approach to identify proteins that function in hSTIM1 clustering following store depletion, and to determine what makes mitotic cells different in this aspect. We have immunoprecipitated proteins that bind hSTIM1 in HEK 293 cells with the Ca2+ store full or depleted in both mitotic and non-mitotic cells. We used iTRAQ labeling to identify proteins that bind hSTIM1 and to obtain relative quantification among the different treatment groups. This will help in defining function of these proteins under the different experimental conditions. We have identified over 400 proteins that co-immunoprecipitate with hSTIM1. The data suggest that hSTIM1 is a component of distinct complexes within the cell and such may have additional functions apart from SOCE in HEK 293 cells. Gene ontology enrichment is being done on this dataset to assign these proteins to different complexes. Deviating ratios of proteins within complexes under different conditions will provide us with an insight into their functions with hSTIM1 during interphase and mitosis.
We are taking a similar approach to identify proteins that function with hSTIM1 during interphase and meiosis using Xenopus oocytes expressing mCherry-tagged hSTIM1.
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Preserving Therapeutic IL-2 Stability and Bioactivity: A Novel Controlled Release Polymeric Drug Delivery Approach
المؤلفون: Husam M Younes and Mohamed ShakerAbstractIntroduction: The application of therapeutic proteins and cytokines like Interleukin-2 (IL-2) for long-term, localized delivery has been hindered by a lack of a delivery device that releases active protein at a concentration within their therapeutic window. The purpose of this oral presentation is to report on the osmotic-driven, controlled-release from novel visible-light photocrosslinked biodegradable elastomeric devices recently designed in an attempt to overcome this limitation.
Materials and Methods: All chemicals were purchased from Sigma-Aldrich and used as received. Novel biodegradable and biocompatible poly (decaneco- tricarballylate) [PDET] elastomers were synthesized by polycondensation reaction between tricarballylic acid and alkylene diols, followed by acrylation and photo-curing. IL-2 loaded micro-cylinder and disk-shaped elastomeric devices were prepared by intimately mixing IL-2 lyophilized powder with the acrylated prepolymer prior to photocrosslinking. IL-2 release was analysed using IL-2 ELISA system and the in vitro bioactivity of released IL-2 was assessed using C57BL/6 mouse cytotoxic T lymphocyte. The influence of various parameters such as the elastomer crosslinking density, the volumetric drug loading percentage and the incorporation of osmotic excipients like trehalose on the release kinetics of the drug was also examined.
Results and discussion: The disk-shaped specimens showed faster IL-2 release profiles than microcylinders, with drug release proceeding via typical zero-order release kinetics. The increase in the device's surface area and the incorporation of trehalose in the loaded lyophilized mix increased the IL-2 release rate. As well, it was shown that the decrease in the degree of prepolymer acrylation of the prepared devices increased the IL-2 release rate. Cell based bioactivity assays showed that IL-2 released over a period of 28 days, retained more than 94% of its initial activity. These bioactivity results represent a highly significant improvement over the other previously published data provided with a quantitative analysis of the actual percentage of bioactive IL-2 released during the period of the release study.
Conclusion: The novel PDET elastomeric drug delivery systems demonstrated to be promising as protein drug delivery vehicles for localized and sustained IL-2 immunotherapy.
Acknowledgements: Work is supported by QNRF through the NPRP grant # 09-969-3-251 awarded to HM Younes.
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Identification and Mapping of Locus on the Long Arm of Chromosome 4 that is Associated with Mental Retardation and Optic Atrophy in a Qatari Aamily with Undelineated Autosomal Recessive Disease
المؤلفون: Yasser Al-Sarraj, Mazen Osman, Yosra Bejaoui, Grisellhi Billedo, Eman Abuazab, Hatem El-Shanti and Jamil Al-AlamiAbstractBackground: Autosomal recessive diseases are the single largest category of single-gene disorders among Arab population. A Qatari family includes 6 individuals from 3 related consanguineous sibships, with mental retardation. The clinical picture comprised significant mental retardation, retinal degeneration, optic nerve atrophy, and ataxic gait. They suffer also from oedemal puffiness of hands and feet. All parents and the unaffected family members are healthy.
Objective: Identification of undelineated autosomal recessive disorders among families in the Arab world, especially in the Gulf region.
Methods: Whole genome genotyping was done by (Illumina 300Kb SNPs), followed by homozygosity mapping and linkage analysis. Targeted resequencing of candidate genes was preformed within the linked loci.
Results and conclusions: Homozygosity mapping revealed a 19.6 MB segment in the long arm of chromosome 4 flanked by rs4345237 (4q12) and rs422140 (4q13.3). This interval contains more than 100 genes, none of which has been implicated in any of the above mentioned phenotype so far. Candidate genes were selected and we are in the process of sequencing them. In addition, whole exome sequencing will be performed to expedite the mutation identification.
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The Generation of a Novel Chimeric Antigen Receptor for Cancer Immunotherapy
المؤلفون: Mariam Abdulaziz Al-MuftahAbstractT-cells genetically modified to express a chimeric antigen receptor (CAR) against a tumor associated antigen are attractive anti-cancer therapeutic agents. The 5T4 cell surface oncofoetal antigen is an attractive target antigen for cancer immunotherapy as it is expressed by a wide spectrum of cancers including gastric, ovarian and colorectal while showing limited expression in normal adult tissues. Previously it was shown that human and murine T-cells engineered to express human 5T4 specific CAR can specifically lyse human 5T4-expressing tumor targets in vitro and in vivo, respectively. This study aimed to isolate single chain variable fragments (scFvs) specific for murine 5T4 (m5T4) and to examine their efficacy in the context of CAR in a fully autologous model. Screening four novel hybridoma cell-lines producing anti-m5T4 monoclonal antibodies to clone the scFv yielded one functional m5T4-specific scFv from the hybridoma cell-line P1C9. The P1C9 scFv expressed as a fusion protein with the Fc domain of human IgG significantly labels m5T4-expressing targets. Murine T-cells modified to express the P1C9 scFv fused to the CD3? molecule can specifically lyse target cells in vitro and result in IFN-? cytokine release, while T-cells expressing the non-signalling CAR derivative; P1C9 scFv fused to the murine MHC-I transmembrane domain, were unable to lyse m5T4-expressing tumor targets. On-going experiments aim to test the efficacy and assess the toxicity of m5T4-specific CAR against m5T4-expressing tumor models in vivo. This model will allow further understanding of how gene-modified T-cells function in an autologous setting with the aim to improve human T-cell based cancer immunotherapy.
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Analyzing the Synergistic Effects of Retinoic Acid and TRAIL on the Induction of Apoptosis in Oral Squamous Cell Carcinoma-Derived Cell Lines
المؤلفون: Ahmed Alsaei, Kwame Osei-Sarfo and Lorraine GudasAbstractHead and neck squamous cell carcinomas (HNSCCs) develop in the mucosal linings of the upper aerodigestive tract and are the sixth leading cause of cancer worldwide. They are initiated by tobacco and alcohol consumption, and by infection with high-risk types of human papillomavirus (HPV). The neoplastic process begins with the normal epithelium progressing through hyperplasia to dysplasia to carcinoma in situ and invasive carcinoma.
Retinoic acid (RA) and its derivatives (retinoids), metabolites of vitamin A, have been recognized as a group of cancer chemopreventive and therapeutic agents, because of their ability to induce differentiation of various types of stem cells and arrest of cellular proliferation. Recent studies show that RA sensitizes colorectal cancer cells to apoptosis by inducing the proapoptotic ligand, TNF-related apoptosis inducing ligand (TRAIL). RA increases the expression of TRAIL receptors, Death Receptors 4 & 5 (DR4/5), while suppressing TRAIL nonfunctional receptors, Decoy Receptors 1 & 2 (DcR1/2) in colorectal cancer cells. In this study, we analyzed the synergistic effects of RA and TRAIL on the induction of apoptosis in human oral squamous cell carcinoma derived cell-lines.
The human HNSCC cell lines, SCC-15, SCC-25, and OKF6/hTERT-1 (an immortalized oral mucosa cell line), were treated either with RA, TRAIL, or RA and TRAIL for 7 days. These treated cells were then analyzed for changes in cell proliferation (by growth curves), gene expression (by semi-quantitative PCR), and markers of apoptosis and differentiation (by Western blot). It was expected that cellular proliferation and expression of DcR1/2 would be reduced in cells treated with RA and TRAIL, while expression of DR4/5 and markers of apoptosis (PARP cleavage) would be higher in RA and TRAIL-treated cells. We show that RA and TRAIL decreased cellular proliferation in the OKF6/hTERT-1 cell-line; however, RA in combination with TRAIL did not result in a significant change in SCC-15 or SCC-25 cell-lines. In addition, Western blot results show that RA and TRAIL increased the cleavage of PARP in the SCC-25 cell-line. Finally, as expected, RA decreased the expression of Oct4, a stem cell marker, and increased the expression of E-cadherin, an epithelial cell marker.
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Autism in Qatar: Quality of Life of the Caregivers
المؤلفون: Sara Hayder Ahmed, Muna Al-Ismail, Nadir Kheir, Ola Goneim, Amy Sandridge and Fadhila Al-RawiAbstractBackground: Caring for an autistic child places significant stress on the lives of family members. To date, no study has evaluated how looking after a child with autism affects quality of life (QoL) of caregivers in Qatar or the Gulf country region. Our study is aimed at quantifying the health-related QoL of caregivers of children with autism in Qatar.
Methods: We recruited two groups of caregivers of children between 3 to17 years old. The first group was formed of caregivers of children with autism from two developmental paediatric rehabilitation clinics, and the second group was formed of caregivers of typically-growing children and who were visiting a family clinic for routine medical check-up. Demographic information of all caregivers and children were collected. The Arabic version of the Short Form-36 (SF-36), which is a generic type questionnaire, was administered to caregivers in both groups to assess QoL.
Results: A total of 98 participants consented to take part in the study. 56 were caregivers of children with autism, and 42 were caregivers of a typically-growing children. There was no statistically significant difference in QoL domains between both groups, but caregivers of autistic children rated their health as poor and likely to get worse (p=0.003). Mental health components were consistently poorer than the physical components in the autistic group, and female caregivers had poorer mental health than males in this cohort of participants (p<0.05).
Conclusion: This study provided evidence for the impact of caring for a child with autism on the life of the caregiver. However, there seems to be a need to develop condition-specific QoL questionnaires that can specifically measure QoL in caregivers of autistic children more accurately than generic questionnaires. The findings should still help health policy-makers provide more focused support to the children with autism and their families.
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The Prevalence of Obesity Amongst School Children and Adolescents in Qatar
المؤلفون: Ladan Davallow, Hanin Abou Ayash, Iqbal El Assad and Amal KhidirAbstractIntroduction: There has been a great increase in the worldwide prevalence of childhood and adolescent obesity and secondary diseases such as diabetes mellitus type II in recent years. However, there is insufficient data regarding this topic in Qatar and the Gulf region.
Objective: To assess obesity prevalence among schoolchildren and adolescents (6–18 years) in independent schools in Qatar.
Methods: This cross-sectional study was conducted in independent schools selected by the Supreme Council of Education in Qatar. Participants were sampled from schools managed by the Ministry of Education in Qatar using a multi-stage random selection with clusters being school type (primary, preparatory, secondary), grade, class section and gender of students. Two questionnaires translated to Arabic (one for grade 4 and one for grade 8 and 11) were used, and weight and height were measured using a portable stadiometer. Ethical board approvals as well as parental permission and students’ assent were obtained.
Results: Data was collected from 19 schools (7 elementary, 6 middle and 6 high schools). Total of 480 children and 1,333 adolescents were enrolled. Height and weight were measured, and body mass index (BMI) was calculated using Center for Disease Control (CDC) guidelines. Overall prevalence of obesity among: a) Grade 4 was 23.3% (27.7% boys and 18.3% girls), b) Grade 8 was 22.4%, (22.2% boys and 22.9% girls), and c) Grade 11 was 17.5% (24% boys and 12.2% girls). Grade 4 and 11 boys were (1.7 and 2.6 times respectively) more likely to be obese than girls, while in grade 8 there was no statistically significant difference among genders. The rates of obesity for all grades were higher than the American rate of 16.9% for children between the ages of 2 to 19 years by National Health and Nutrition Examination Survey (NHANES).
Conclusion: There is a high prevalence of obesity amongst schoolchildren and adolescents in Qatar, boys more than girls. This pilot study highlights the need for a bigger scale study to further evaluate obesity among children and adolescents and start concrete interventions.
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Community Pharmacists in the State of Qatar: A Survey of their Smoking Cessation Knowledge and Educational Interests
المؤلفون: Maguy Saffouh El Hajj, Reem R Al Nakeeb and Rajaa A. Al QudahAbstractBackground: Cigarette smoking is one of the preventable causes of ill health in Qatar. Qatar community pharmacists are in an ideal position to play an important role in smoking cessation. This role necessitates adequate smoking cessation knowledge and education. The study objectives were to assess Qatar community pharmacists' smoking cessation knowledge and to gauge their perceptions of which aspects of smoking-related education would be most interesting.
Methods: A pretested survey was used to solicit community pharmacists' anonymous responses. The survey was designed after reviewing relevant smoking cessation literature. A phone call was made to all community pharmacists in Qatar to request their participation. Interested pharmacists were sent the survey link by email or by fax. Data was descriptively analyzed using the Statistical Package of Social Sciences software version 18.
Results: Over 20 weeks, we collected 112 surveys (35% response rate). Smoking cessation knowledge was evaluated using 8 true or false questions. Thirty seven percent of respondents scored less than 60% and 13% scored more than 80%. The mean score was 61% with a standard deviation of 17%. Eighty-nine percent of respondents indicated that they have not received before any smoking cessation education. Nevertheless, at least 70% indicated that they were interested in receiving additional smoking cessation education. Respondents were mostly interested in receiving education on motivating smokers to quit and on counseling on behavioral techniques (89% and 86% respectively). Sixty nine percent indicated a preference for mailings of printed materials as method of information delivery.
Conclusion: Despite their low smoking cessation knowledge, Qatar community pharmacists are interested in receiving additional smoking cessation education. A smoking cessation education program should be offered to these pharmacists to give them the knowledge they need to be competent smoking cessation counselors.
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The Effect of Serum Lipoproteins on Amiodarone Metabolism in Cultured Primary Rat Hepatocytes
المؤلفون: Dalia Hamdy and Dion BrocksAbstractPurpose: To examine the effect of serum lipoproteins on amiodarone (AM) metabolism in cultured primary rat hepatocytes.
Method: Primary rat hepatocytes were isolated from normal lipidemic (NL) or hyperlipidemic (HL) Sprague Dawley rats. All experimental groups were treated with AM (500 ng/mL) for 0–72h (n=18 wells for each time point). In preincubation groups, hepatocytes were pre-incubated for 24 h at 37°C with media or 5% NL or HL serum in media. After 24 h, the medium containing serum was removed and treatment was initiated with drug incubated with media alone. For serum co-incubation groups, the AM serum mixture was added to hepatocytes. Experiments were terminated at various time points by addition of 0.5 mL 1N NaOH to each well and samples collected in Eppendorf tubes and stored at −30°C until analyzed for the concentration of AM remaining.
Results: In absence of serum, there was no significant difference in the area under the % AM recovering time curve (ARE) between the NL and HL hepatocytes over the time period from 0–72h. However, ARE from 0–24h in HL rat hepatocytes (1630±39.3 % h) was significantly higher than that of the NL rat hepatocytes (1409±57.2 % h). The co-incubation of NL serum led to a significant increase in the ARE in the NL hepatocytes compared to the incubations in the absence of the serum. The addition of HL sera, whether it be as pre- or co-incubations, led to significant increases in the ARE compared to media only and NL serum incubations. In addition the co-incubated NL hepatocytes had significantly higher (6288% h) ARE when exposed to HL serum than the pre-incubated (4552 % h) cells.
Conclusion: Serum pre-incubation decreased the amiodarone metabolism in cultured primary hepatocytes due to down regulation of CYP enzymes. Serum co-incubation resulted in significantly lower AM metabolism than the corresponding pre-incubation groups due to a decrease in AM unbound fraction. The hypothesized enhanced association of drug with VLDL and LDL fractions in co-incubation with HL serum compared to NL serum was not sufficient to increase the uptake of the drug into hepatocytes and increase the drug metabolism significantly between those two groups.
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Mechanistic Release Study of Water Soluble Drugs from Poly (Dimethylsiloxanes) Elastomeric Matrices
المؤلفون: Husam M Younes, Sandi Ali-Adib, Nazish Khan, Kawthar Tawengi and Dana BakdashAbstractIntroduction: Controlled drug release from implantable silicone elastomers was reported to occur mainly via the osmotic rupture release mechanism. In this work, we are attempting to determine the effects of drug volumetric loading, particle size, device shape, and dissolution media on the release rate of the water-soluble osmotically active drug, Papaverine Hydrochloride (PH) from silicon elastomers.
Materials and Methods: Medical grade silicone (Sylgard kit) was purchased from Dow Corning. All other chemicals were purchased from Sigma-Aldrich and used as received. The release profiles from devices of three geometries (cylinders, cubes and tablets), of different drug particle sizes (< 45μm, 63–125μm or 125–250μm) in different dissolution media (phosphate buffered saline, distilled water, and 3% sodium chloride solution) were investigated. The effect of degree of elastomer crosslinking and the percentage of volumetric loading of the osmotic excipient and pore forming agent, Trehalose, on the release rate were also investigated. The drug fraction released of PH was analyzed using ultraviolet spectrophotometric analysis. Data obtained was then plotted as cumulative percentage release against time and then further analyzed.
Results and Discussion: Contrary to previous reports, devices formulated with the same volumetric loading and smaller drug particles sizes released drug faster than those devices with a larger particle size. The drug release from tabular implants was of faster rate when compared to cylindrical and cubic devices. Contrary to the expected, higher drug release rate was also observed from cubic elastomeric devices with higher crosslinking density. In addition, the release profiles demonstrated that osmotic release was the predominant mechanism governing the release of PH from silicone elastomers.
Conclusion: Our results show that osmotic rupture is the predominant mechanism of release of PH from silicone elastomer. Further studies must be conducted to confirm the effect of the elastomer crosslinking density on drug release rate.
Acknowledgements: This report was made possible by a UREP award [UREP 07-120-3-027] to HM Younes from the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the authors.
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Newborn EEG-Based Automatic Abnormalities Diagnosis Scheme using a Time-Frequency & Image Processing Approach
المؤلفون: Larbi Boubchir and Boualem BoashashAbstractElectroencephalogram (EEG) is a representative signal containing information of the electrical activity generated by the cerebral cortex nerve cells; it has been the most utilized signal to clinically assess brain activities, and to detect abnormalities such as epilepsy. However, the manual detection of such brain abnormalities as epilepsy or seizure includes visual scanning of EEG recordings, which is very time consuming especially in the case of long recordings. So, the EEG signal parameters are extracted and analyzed using computer based digital signal processing techniques are highly useful in diagnostics and more suitable for detecting and classifying EEG abnormalities.
This work aims to develop novel features extracted from the time-frequency distribution (TFD) of the EEG signals including newborn for the purpose of classifying these signals in three possible categories i.e.: 1) acquired from healthy subjects, or 2) epileptic patients during normal brain activity, or 3) epileptic patients while experiencing seizures.
The proposed method for classifying EEG signals includes the three following stages:
- Time-frequency decomposition of EEG signal using the quadratic time-frequency representations (TFR).
- Features extraction from TFR.
- Features classification in order to assign the signal to one abnormality class: mild, moderate or severe abnormality.
The experimental results show that the proposed method provide better results using certain types of Quadratic TFDs such as the Modified-B distribution or the Spectrogram distribution in combination with the support machine classifier to detect and classify the epilepsy. We also found that the performance of this method is not related only to the TFR and the classifier choice but is also dependent on the choice of significant features. We are currently developing new image processing techniques to extract new features from the TFR considered as an image. The design is based on the use of edge and contour detection, and, segmentation methods in order to define new features such as the number, the shape and the localization of the components.
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Design of Quadratic Time Frequency Distribution and Application to the Analysis and Detection of Fetal Movements
المؤلفون: Taoufik Ben Jabeur and Boualem BoashashAbstractBackground: Fetal movements are clinically correlated to fetal wellbeing. Ultrasounds are the most accurate measurements of the fetal movement but expensive and intrusive. To avoid these constraints, Fetal activity is captured through data acquired using low cost and nonintrusive accelerometer . Time-frequency distributions (TFDs) are often used to represent the energy, temporal and spectral characteristics of non-stationary signals in the time and frequency plane.
Many quadratic TFDs were proposed in the literature such as Wigner-Ville distribution, Spectrogram, B-Distribution, Choi-Williams , etc. The drawbacks of the majority of these techniques is that only a few parameters can be modified in the kernel, generally the lag and Doppler parameters, so that they cannot be easily adapted to the data.
Objectives: This work aims at designing a new kernel with several parameters that leads to a higher resolution time frequency representation (TFR) of the signal, therefore improving the characteristic of the fetal movement.
Methods: The proposed TFD can be considered as an extension of the Gaussian TFD (also called Choi-Williams distribution). The kernel function of the proposed kernel is given by the sum of the weighted derivative Gaussian TFD (refer to the equation).
Results and Conclusion: The weighted parameters in the above formula can be estimated by maximizing the concentration of the instantaneous frequency. The resulting TFD is compared with other methods and applied to the analysis and classification of the fetal movement data recorded by the accelerometers. The results obtained indicate that the proposed time-frequency methodology allows the detection of fetal movement data recorded by accelerometers.
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Newborn EEG Seizure Detection Using Time-Frequency Matched Filtering
المؤلفون: Boualem Boashash and Ghasem AzemiAbstractBackground: The analysis of Electroencephalography (EEG) signals acquired from epileptic babies shows that seizures can be modeled as piecewise linear frequency modulated (LFM) signals. This fact motivated the use of time-frequency matched filters (TFMFs) for seizure detection in newborn EEG. A TFMF is characterized by a unique test statistic, which is found based on the time-frequency (TF) correlation between the signal under analysis and a template. The test statistic is compared with a threshold to determine the presence or absence of the template in the signal under analysis.
Objectives: We present two seizure detection algorithms based on the general class of TFMFs and an improved algorithm in the ambiguity domain and evaluate their performance using real EEG signals.
Methods: The method includes the following stages:
Based on TF analysis of newborn EEG, we create a template set containing M piecewise LFM signals with L pieces and slopes.
We define test statistics based on the TF correlation between the EEG signals under analysis; we use the Wigner-Ville distribution (WVD) and other quadratic Time-Frequency Distributions.
The test statistics are compared with a predefined threshold.
Results: We evaluated the performance of the proposed method using a database of newborn EEG signals. For each method, we found the area under the receiver operator characteristic curve (AUC) as the performance criteria. All the methods detected seizure accurately with AUC more than 0.9.
Conclusions: This work shows that TFMFs can detect seizures in newborn EEG with a very high accuracy. The optimization of the parameters of the TFDs and the use of fast and memory efficient algorithms for computing TFDs can improve the performance of the methods.
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Caring for a Child with Autism; Burden and Quality of Life of the Caregivers in Qatar
المؤلفون: Nadir Kheir, Ola Ghoneim, Amy L Sandridge, Muna Al-Ismail, Sara Hayder and Fadhila Al-RawiAbstractIntroduction: Autism spectrum disorder (ASD) affects children at around the age of 3 years old and last throughout the person's lifetime. ASD imposes great burden on the family, and forces family members to considerably modify their daily lives to suit their reality with autistic child(ren). To our knowledge, no previous research assessed the burden of ASD on the lives of parents/caregivers of autistic children in Qatar or the Gulf region.
Methods: Caregivers of a child with autism between 3–17 years were recruited from children rehabilitation clinics. The control group was represented by caregivers of a typically-growing child visiting a primary health care facility for a routine medical examination. Data collected from both groups included demographic information of caregivers and children and quality of life information. The Lebanese Arabic version of the Short Form-36 (SF-36) was used to assess quality of life.
Results: Children in the AG spent more time indoors, watching TV, or sleeping than children in the control group (p←0.05). Around 40% of caregivers in the AG said they would encourage their child to get married and become parent when s/he grows up. Half of the sample in the AG utilizes special education classes and other facilities, and the remaining half has access problems. There was no statistically significant difference between quality of life domains between the two groups of caregivers, but caregivers of autistic children rated their health as poor and likely to get worse (p=0.003). However, mental health components were consistently poorer in the AG compared to the physical components, and female caregivers also had poorer mental health than males in this cohort of participants (p<0.05).
Conclusion: This study provided evidence for the impact of caring for a child with autism on the life of the caregiver. The findings should help health policy-makers provide more focused support to the children with autism and their families.
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Medications in Qatar's Homes: What are They and Where Are They?
المؤلفون: Nadir Kheir, Maguy El Hajj, Karry Wilbur, Rihab Kaissi and Adil YousifAbstractBackground: Drug therapy is the most used intervention for the treatment and prevention of diseases. However, if used inappropriately, drugs can cause more harm than good. Improper drug storage and disposal can have direct impact on public safety, the environment, and healthcare services. No previous studies have examined how medications are stored, used or disposed-off in Qatari homes.
Objectives: To explore how medications are stored in Qatari homes, and to identify how unwanted medications are disposed of.
Methods: This was cross-sectional, descriptive, and epidemiological study. A list of randomly selected telephone numbers was generated from Qatar's telephone directory. Individuals answering calls were provided with the study objectives, and asked if they wished to participate. Those who offered verbal consent were interviewed in Arabic or English using a multi-part pre-tested survey instrument. The survey contained questions related to the participants’ socio-demographic characteristics as well as to the stored medications at home.
Results: Data were collected from a total of 49 households. The sample contained an ethnic mix of whom 28% stored medications in their bedroom, and 13% in a fridge. Most respondents disposed of unwanted medicines by throwing in the trash. The majority of respondents sought information related to drugs from doctors. Only 6% identified pharmacists as their primary source of information related to drugs. There seems to be poor or no correlation between household income and number of drugs stored or the method of disposal of medicines.
Discussion and Conclusions: The results raise concerns about how medications are stored and disposed-off in the community. The fact that no household routinely returned unwanted medications to a pharmacy for proper disposal places the environment at risk. There is need for societal awareness on the safe handling and storage of drugs in homes, and pharmacist should do more to raise awareness about their expected professional role.
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Failure and Injury Locus of Anterior Cruciate Ligament: A Finite Element Study
المؤلفون: Abdel Magid Hamouda, Alexander D Orsi, Ashkan Vaziri and Hamid Nayeb-HashemiAbstractBackground: Anterior cruciate ligament (ACL) tears are common injuries occurring upwards of 250,000 times annually only in the U.S. These injuries create an annual billion dollar expense. It is important to understand these injury mechanisms as these injuries continue to be one of the largest problems in orthopedic sports medicine. Improved understanding of the injury mechanisms may improve prevention, rehabilitation and surgical procedures.
Objective: This study used a 3-Dimensional finite element (FE) knee joint model to investigate the combinations of movement, which cause ACL injury.
Method: Digital bone structures were created from magnetic resonance images (MRI). Ligament bundles were modeled based on the origins and insertion sites determined from MRI. Bone was modeled as rigid, and a transversely isotropic Mooney-Rivlin material was applied to the ligament structures. This study incorporates a novel approach for developing bundle specific prestrain within 3-D ligament structures. The bundles were stretched from their zero load lengths to their reference lengths, producing a strain field mimicking the in vivo strain conditions of the ACL at full knee extension. A failure locus was created by performing multiple FE simulations of knee joint motion combinations until ACL failure.
Result: The relationship between knee joint orientation and ligament rupture was plotted providing a spectrum for the propensity of ACL injury based on knee joint orientations, known as a failure locus. The locus shows which combinations of internal/external femoral rotation and varus/valgus angle cause ACL failure. The results show the posterolateral bundle more susceptible to rupture than the anteromedial bundle in 17 of the 22 simulations. The results also show 45% less varus angle needed for ligament failure relative to valgus angle. The results highlight femoral external rotation as an important factor for ACL injury as it decreases the failure angle by an average of 23% compared to femoral internal rotation.
Conclusion: These results have various clinical applications. In sports where ACL injuries are prevalent, training programs can be adapted to address the avoidance of harmful knee orientations.
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HIV Molecular Epidemiology in the Middle East and North Africa: Understanding the Virus Transmission Patterns
المؤلفون: Ghina Mumtaz and Laith Abu-RaddadAbstractBackground: Human Immunodeficiency Virus Type I (HIV-1) is characterized by a high genetic variability. The distribution of HIV-1 subtypes in a population can help track transmission patterns and the evolution of the epidemic. The Middle East and North Africa (MENA) continues to be perceived as a region with limited HIV epidemiological data, but recent research indicates that nascent HIV epidemics appear to be emerging among high-risk groups including injecting drug users (IDUs), men who have sex with men, and female sex workers.
Objective: To review all evidence on HIV-1 subtype distribution in MENA where there remain several gaps in the understanding of the HIV epidemic.
Methods: A comprehensive systematic review of all HIV-1 molecular epidemiology data in MENA was undertaken. Sources of data included 1) PubMed, 2) country-level reports and database including governmental and non-governmental organizations publications, and 3) international organizations reports and databases.
Results: In several countries such as Lebanon, Saudi Arabia, and Yemen, a very diverse distribution of HIV-1 subtypes was observed reflecting principally travel-related exogenous exposures. A trend of a dominant HIV-1 subtype was observed in few other settings and was often linked to HIV transmission within specific high-risk core groups such as subtype A and CRF35_AD among IDUs in Afghanistan, Iran, and Pakistan; and subtype C in heterosexual commercial sex networks in Djibouti and Somalia. Subtype B was predominant in Northern Algeria, Tunisia, and Morocco, but this appeared to reflect a mix of indigenous endemic transmission and exogenous exposures of West European and North American origin.
Conclusions: Multiple introductions of HIV-1 variants due to exogenous exposures of nationals seemed common to all MENA countries, as observed from the high diversity in subtypes or the high genetic divergence among any specific subtype even if predominant. This in part reflects the high population mobility in MENA. In several countries though, epidemic-type clustering of specific subtypes suggests established or nascent HIV epidemics among classic core risk groups for HIV infection. With overall weak surveillance systems in MENA, molecular investigations could help identify the emergence of hidden epidemics among high-risk groups. HIV prevention efforts must be prioritized for these groups.
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Biophysical Properties of Xenopus TRPV6 Channel and its Regulation by TRPC1
المؤلفون: Raphael Courjaret, Arwa Daalis, Satanay Hubrack, Shirley Haun and Khaled MachacaAbstractTransient Receptor Potential (TRP) ion channels are formed by either homomeric or heteromeric assembly of four TRP subunits that have six transmembrane domains (TM) and a P-loop located between TM5 and TM6 defining the channel pore. So far 30 different subunits classified in 6 families sharing as low as 20% homology, have been identified in mammals and about 20 in Xenopus. Although heterotetramers can be formed within a family, the assembly of subunits from members of different families was thought to be unlikely. We here propose that TRPV6 and TRPC1 subunits can co-assemble in the Xenopus oocyte. Western blots performed on naive oocytes lysates revealed that they express both TRPV6 and TRPC1 proteins. Furthermore, co-immunoprecipitation of tagged xTRPV6 and xTRPC1 proteins expressed in oocytes suggested a heteromeric assembly. In mammals, TRPV6 is mainly expressed in intestinal epithelia and in the placenta where it forms a homomeric channel with high calcium permeability whereas TRPC1 is a ubiquitous protein forming cationic channels with an unclear gating mechanism.
In oocytes, over expression of xTRPC1, as previously reported, did not induce any resting ionic current. Conversely, oocytes overexpressing xTRPV6 alone did show an inward rectifying cationic current that could be blocked by La3+ ions and Ruthenium red. As described for mammals, the xTRPV6 channel was largely permeable to calcium ions and displayed an anomalous mole fraction effect. A striking distinction with its mammalian counterpart is the high permeability of the xTRPV6 channel to Mg2+ over other divalents (Mg2+>Sr2+>Ba2+>Ca2+), the Mg2+/Ca2+ ratio being 2.08.
This high permeability to Mg2+ could be abolished by a point mutation in the P-loop (D525N) lowering the ratio to 1.18. Co-expression of xTRPC1 and xTRPV6 lead to a very strong reduction in the current amplitude and in cationic selectivity, the Mg2+/Ca2+ ratio also dropping to 1.18. Further investigations using heterologously expressed xTRPV6 and xTRPC1 in HEK293, allowing whole-cell recordings, will help us clarify the selectivity and the regulation of the channel. The potential interaction between TRPV6 and TRPC1 in mammals will also be examined using tissue extracts and selected cell lines.
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Pharmacy Students' Attitudes Toward Pharmaceutical Care in Qatar
المؤلفون: Maguy Saffouh El Hajj, Ayat Hammad and Hebataila M. AfifiAbstractBackground: Pharmacy practice has recently shifted from medication supply to pharmaceutical care (PC). Pharmacy educators must prepare students to provide PC. Their responsibilities are not only limited to give students knowledge and communication skills but to motivate them to perform PC. The study objectives were to investigate Qatar pharmacy students' attitudes toward PC, to identify the factors that influence their attitudes toward PC, and to recognize their perceived barriers for PC provision.
Method: Qatar University college of pharmacy is the only pharmacy college in Qatar. A cross sectional survey of Qatar University pharmacy students was made. The students completed an online anonymous survey designed based on Standard Pharmaceutical Care Attitudes Survey (PCAS).Data was descriptively analyzed using Statistical Package for the Social Sciences version 18. Influence of sociodemographic characteristics on students' attitudes was assessed using Kendall's tau_b test.
Result: Over 4 weeks, 46 surveys were submitted (90% response rate). All respondents agreed that PC practice is valuable and that the pharmacist primary responsibility is to prevent and resolve medication therapy problems. Most respondents believed that PC provision is professionally rewarding (96% of respondents), and that all pharmacists should provide PC (91%). Highly perceived barriers for PC provision included lack of access to patient medical information (76% of respondents), inadequate drug information sources in the pharmacy (55%) and time constraints (53%). Professional year and practical experience duration were significantly inversely associated with students attitudes (correlation coefficients are −0.30 and −0.37 respectively p <0.05). No statistically significant correlations existed between other characteristics and students attitudes.
Conclusion: Qatar pharmacy students indicated positive attitudes toward PC. However, they perceived several barriers for PC provision. Efforts should be exerted by Qatar's government to help these future pharmacists in overcoming these barriers.
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Calcium Waves in the Xenopus Oocytes Trigger Store Operated Calcium Entry
المؤلفون: Raphael Courjaret and Khaled MachacaAbstractThe oscillation of cytoplasmic calcium concentration exists in a large number of non-excitable cells such as astrocytes in the brain, intestinal cells and oocytes (Fig.1). This rhythmic activity carries information into the cell, regulating various processes such as gene expression or transmitter release. In some cells, such as Xenopus oocytes, the oscillations can rely only on calcium being released in the cytoplasm from intracellular stores after stimulation of inositol triphosphate (IP3) receptors located on the endoplasmic reticulum (ER). To refill the intracellular stores in the ER, the cell has to import extracellular calcium. This is achieved through the STIM/Orai pathway where an ER calcium sensor (STIM) is activated by store depletion and in turn interacts and opens a calcium channel in the plasma membrane (Orai) leading to calcium influx, a process known as Store Operated Calcium Entry (SOCE). In the present work we evaluated the interactions between SOC and intracellular calcium oscillations in Xenopus oocytes. Intracellular calcium levels were monitored using the amplitude of the endogenous calcium-activated chloride currents. Following injection into the cells of a non-hydrolysable analog of IP3 (IP3-DF), long lasting calcium oscillations could be triggered as well as SOCE ( Fig. 1 ). The calcium oscillations were more efficient in promoting SOC than store depletion by ionomycin (2.34 ± 0.55 nA, n=13 vs 0.05 ± 0.02 nA, n=8), the mechanisms involved are currently under study. We also observed that activation of SOC could trigger a calcium wave in a dose-dependent manner following a “Calcium Induced Calcium Release” pattern. This suggests that SOC might not only be involved in replenishing the calcium stores but also in the regulation of the amplitude and timing of calcium oscillations. The well known down-regulation of SOC during oocyte maturation should therefore have important functional consequences on intracellular calcium oscillations.
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RNA-Seq Reveals Novel Mutation Selection and Gene Expression Changes in Ovarian Cancer Metastasis
AbstractThe mutation landscape of cancer is known to evolve as different metastasis develop. As the cancer spreads, certain mutations are selected for and gene expression changes are needed to adapt to the new environment. We have begun to document the changes that occur as cancer metastasizes using Next- Generation Sequencing of mRNA from Ovarian primary tumor and its peritoneal and lymph node metastases. We used data generated using deep-sequencing to evaluate the clonal relationships among primary and metastatic cancers to uncover the natural history of ovarian cancer progression. Using this approach, we have documented numerous Single Nucleotide Polymorphisms (SNP) changes including changes in SNP frequency as the cancer spreads. In combination with gene expression changes these will serve as a powerful tool to begin understanding the continual evolution of cancer in response to new environments.
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Investigation of the Role of Notch Signalling in the Microenvironment-Mediated Tumorigensis of Breast Cancer
المؤلفون: Pejah Ghiabi and Jeremy Arash Rafii TabriziAbstractRecently, a speculative model is proposed that tumor tissue is continuously regenerated by a small population of self-renewing cancer stem cells responsible for initiation, growth and propagation of tumor. Tumor cells reside in a “niche” and have constant interaction with the niche components including tumor vasculature, bone marrow mesenchymal stem cells (BM-MSCs) and the components of the extracellular matrix. It is believed that the growth advantage acquired by tumor cells as well as the ability of cancer stem cells (CSCs) to maintain tumor propagation is partly the outcome of this interaction.
Our study intends to better characterize this crosstalk by looking into the possibility of BM-MSC/endothelial cell-mediated activation of Notch pathway in breast cancer cells through production of certain cytokines aiming at proposing novel therapeutic approaches for targeting this disease.
The CSCs were enriched by culturing breast cancer cells (BCC) in 3D media to obtain multicellular spheres for further analysis. BM-MSC and Akt-activated endothelial cells were co-cultured with BCC and spheres to assess their capability in promoting cancer cell growth. RNA interference approach was applied to Notch3 to determine its role in BCC survival by the niche players. A human cytokine array was used to identify the cytokines that showed different expression patterns in the BCC co-cultures with the niche residents.
BM-MSC or Akt-activated Endothelium was able to increase BCC growth up to 4- and 5-fold, respectively, in contact and under serum-free condition. Blocking Notch3 in BCC or spheres by siRNA or inhibition of notch pathway by GSI reduced the proliferation rate of both entities to 2.5-fold, which might underline the role of notch in the interaction between tumor cells and the niche components. Also, several cytokines were identified that were differentially regulated in co-cultures system among which IL6, IL8, and GROa showed significant up-regulation.
Our preliminary data suggest the role of BM-MSC and endothelial cells in breast cancer growth and survival. Our results propose the idea of notch involvement in this interaction through stimulation by certain cytokines. Further investigation is required to elucidate the exact mechanism that is triggered by these cytokines in tumor propagation and maintenance.
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Interference of Zinc Chelation with Cancer Cell Proliferation
المؤلفون: Ghizlane Bendriss and Khaled MachacaAbstractCell division is a complex process tightly regulated by several classes of genes. Cancers occur primarily due to misregulation of this machinery, resulting in uncontrolled growth of cells. We recently showed that the transition metal chelator, TPEN, blocks entry into meiosis of Xenopus oocytes and targets a protein involved in cell cycle: Cdc25c. Cdc25c is a dual specificity phosphatase that plays crucial roles in cell cycle progression particularly during the G2-M transition of the cell cycle. Analysis of recombinant Cdc25c metal content revealed that Cdc25c is a Zn2+-binding metalloprotein (Lu Sun et al., 2005).
Based on these findings we hypothesize that Zn2+ is an important cofactor for Cdc25c to adopt the right conformation to recognize and interact with its substrate Cdc2. To test this hypothesis, we used Arabidopsis Cdc25c because the Zn coordinating residues have been identified in this protein. This analysis identified the following residues as potential Zn-coordinating residues: H420, C507, C513, H516, and H517. To test whether these residues coordinate Zn we have mutated them to Ala and are presently purifying the mutant and wild-type proteins as recombinant proteins to test their phosphatase activity and ability to induce entry into M-phase following microinjection into oocytes.
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Patterns of HIV Infection Among Spousal and Cohabiting Sexual Partnerships in Sub-Saharan Africa
المؤلفون: Hiam Chemaitelly and Laith J. Abu-RaddadAbstractBackground: The reasons behind the differences in the levels of discordancy (that is one partner testing HIV positive while the other testing HIV negative) among spousal and cohabiting partnerships affected by HIV across sub-Saharan Africa (SSA) remain inadequately understood. Recently, many randomized clinical trials have shown substantial efficacies for several prevention interventions among these partnerships.
Moreover, there has been an intense debate about the priority of HIV prevention interventions among discordant couples relative to other prevention approaches such as among commercial sex networks.
Objective: To describe and explain patterns of HIV infection among spousal and cohabiting sexual partnerships, across a range of settings in SSA.
Methods: Demographic health survey (DHS) data for 20 countries in SSA were used to estimate the prevalence of HIV sero-discordancy among stable partnerships with at least one HIV-infected individual in the partnership (P), prevalence of discordancy among all stable partnerships in the population (S), prevalence of discordancy among the entire sexually active population (A), and prevalence of discordancy among HIV infected individuals (I).
Results: Two distinct patterns of HIV among stable partnerships were observed. Countries with low HIV prevalence had a high discordancy prevalence among P and I ranging from 48.4–87.8% and 30.6–60.0%, respectively, but low discordancy prevalence among S and A ranging from 0.4–6.4% and 0.2–3.8%, respectively. Conversely, countries at hyper-endemic HIV epidemics had a low discordancy prevalence among P and I ranging from 36.3–58.5% and 17.2–46.0%, respectively, but high discordancy prevalence among S and A ranging from 9.3–17.2% and 5.8–8.3%, respectively.
Conclusions: Two distinct patterns of HIV in stable partnerships were observed. In high prevalence settings, many partnerships were affected by HIV but relatively few were discordant, whilst the opposite was true for low prevalence settings. This pattern may be arising from variations in the HIV transmission probability which is dependent on biological and behavioral factors and might also be affected by the frequency of infection from external partners especially in high prevalence countries. These findings may complicate considerations for rolling out prevention interventions among stable discordant partnerships in SSA.
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Trafficking and Regulation of Orai1 in Mammalian Cells
المؤلفون: Abdelilah Arredouani, Timothy E McGraw and Khaled MachacaAbstractStore-operated Ca2+ entry (SOCE) is activated by endoplasmic reticulum Ca2+ store depletion and is a major Ca2+ influx pathway in non-excitable cells. It is widely accepted that Orai1 protein in the plasma membrane (PM) is the channel that mediates SOCE in many cell types. Orai1 is activated when STIM1, an ER transmembrane protein, senses a decrease in the ER Ca2+ concentration and redistributes to ER-PM junctions, where it recruits Orai1 in coincident puncta. We have recently shown that at rest Orai1 actively recycles between an endosomal compartment and the cell membrane in Xenopus laevis oocytes and that ER Ca2+ store depletion translocates most of the Orai1 to the PM. We have also shown that during oocyte maturation Orai1 is internalized resulting in the absence of SOCE in the Xenopus egg. In mammalian cells, mitosis is the only know physiological situation where SOCE is inhibited but the underlying mechanism is not fully understood. In this study we investigated the trafficking of Orai1 in CHO cells that express a tagged Orai1. We also looked at the distribution of Orai1 during mitosis. We show that at steady state about 40% of the total Orai1 pool is at the PM whilst the remaining 60% localizes intracellulary, suggesting that Orai1 constitutively recycles between the two compartments. After the depletion of the ER Ca2+ stores the distribution of Orai1 shifts drastically with now most of the protein localized at the PM. Moreover, we show that the rate of Orai1 exocytosis is 3 fold faster after the depletion of the ER Ca2+ stores. During mitosis the total expression of Orai1 is reduced and the fraction of plasma membrane Orai1 tend to be less than in interphase cells. A fraction of the mitotic cells show no Orai1 expression at all. Interestingly, the reduction of Orai1 expression is reversed by inhibiting the proteosome complex, suggesting that Orai1 is degraded during mitosis.
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Estimating HIV Incidence Rate among Stable Sexual Partnerships in Sub-Saharan Africa
المؤلفون: Laith Abu-Raddad and Hiam ChemaitellyAbstractBackground: Empirical evidence suggests that HIV incidence rate within stable discordant sexual partnerships in sub-Saharan Africa (SSA) varies between 1.2 and 19.0 per 100 person-years. Estimating HIV incidence rate within stable discordant partnerships is critical for determining the contribution of HIV sero-conversions among these partnerships to total HIV incidence.
Objective: To estimate HIV incidence rate within stable discordant partnerships using nationally representative data and explore potential underlying factors contributing to their variability across a range of epidemic settings in SSA.
Methods: We constructed a mathematical model based on competing-hazards formalism to estimate HIV incidence rate within stable discordant partnerships across 20 countries in SSA. We also used the model to analyze the patterns of HIV discordancy in SSA. The model was parameterized using Demographic Health Survey data and analyses were conducted at endemic equilibrium. Sensitivity analyses were performed to explore the dependence on the dynamical drivers of discordancy.
Results: Our model fitted well the empirical epidemiological measures of HIV discordancy and yielded an estimate for HIV incidence rate among discordant partnerships of 14.7 per 100 person-years (95% CI 9.9–19.4 per 100 person-years). HIV incidence rate ranged between 3.9 and 34.9 per 100 person-years across the countries. We also identified HIV incidence rate within stable discordant partnerships and HIV incidence rate from sources external to the partnership (or equivalently HIV prevalence) as key determinants of the variability in discordancy measures across SSA.
Conclusions: Our estimate for the HIV incidence rate among discordant partnerships agrees well with empirical estimates for this measure. There is however considerable variability across the countries. Biological and behavioral factors including differences in transmission rates such as due to male circumcision, may have contributed to the variability in HIV incidence rates among discordant partnerships across SSA. More research is needed to elucidate the determinants of this variability in incidence rates.
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SIRT1 Regulates Hyperglycemia-Induced Vascular Senescence
المؤلفون: Gnanapragasam Arunachalam, Samson Mathews Samuel, Isra Marei, Hong Ding and Christopher TriggleAbstractBackground: 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, pro-atherosclerotic, and prothrombotic. Hyperglycemia-mediated oxidative stress elicits irreversible growth arrest in endothelial cells, which is referred as “stress-induced premature senescence”. Endothelial cell senescence has recently been postulated as an important cause of type-2 diabetes-associated vascular aging. High glucose-induced endothelial senescence exaggerates vascular inflammation and thrombosis in the vessels, promoting the development of diabetic-associated cardiovascular events. Sirtuin 1 (SIRT1) is highly expressed in vasculature and distinctively controls angiogenic signaling in endothelial cells. Recently, SIRT1 has been identified as an important regulator of endothelial cell senescence-like growth arrest and dysfunction. However, the mechanism underlying the high glucose induced endothelial cell senescence leading to vascular dysfunction is not fully understood.
Methods: Mouse microvessel endothelial cells were exposed to normal (11mM) and high glucose (40mM) for 72 hrs. The level of SIRT1, p21 and phospho-acetylated status of Foxo1 were measured by immunoblotting. To measure senescence, cells were fixed and stained for senescence-associated B-galactosidase activity. The percentage of B-galactosidase positively stained (blue color) cells was counted.
Results: Immunoblot analysis reveals that high glucose exposure caused a significant reduction of SIRT1 level along with altered phospho-acetylation levels of Foxo1 proteins. Furthermore, high glucose treatment increased the percentage of senescence-associated B-galactosidase activity in endothelial cells.
Conclusion: Collectively, these data suggest that high glucose induced depletion of SIRT1 plays a crucial role in diabetes-associated endothelial cell senescence and strengthens concept that activation of SIRT1 is an important target for pharmaco-therapy for diabetes-associated endothelial dysfunction and vascular aging. This abstract is part of project funded by: NPRP: 08-165-3-054
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The Prevalence of Hepatitis C Virus in Egypt: A Systematic Review
المؤلفون: Yousra Ali Mohamoud and Laith J. Abu-RaddadAbstractBackground: Hepatitis C virus (HCV) currently infects around 2% of the world's population. Among all nations, HCV prevalence ranges from 0.01% in Scandinavia to 3% in North Africa, with one exception: Egypt. Egypt has the highest prevalence of HCV in the world, estimated nationally at 14.7%. Numerous HCV prevalence studies have published various estimates from different Egyptian communities, suggesting that Egypt, relative to the other nations of the world, might be experiencing an intense ongoing HCV transmission.
Objectives: To review all the evidence on the epidemiology of HCV transmission among different population groups in Egypt.
Methods: This was a systematic review following the PRISMA guidelines of all prevalence data on HCV infection in Egypt. Sources of data included PubMed, international organizations' reports and databases, and country-level reports and databases. Measures were classified into different population categories according to risk of infection.
Results: Seventy-four studies have measured HCV prevalence in Egypt in populations at varying levels of risk. Among Egypt's general population, HCV prevalence in pregnant women was 8.6%, and among blood donors it ranged between 9.0% and 23.2%. A nationally representative survey reported a prevalence of 14.7%. Among populations at high risk of infection, HCV prevalence was found to be as high as 58.3% in multi-transfused children, and 87.5% in adult dialysis patients. Among populations at intermediate risk, diabetic children had a prevalence of 3.1%, barbers a prevalence of 12.3%, health care workers a prevalence of 15.7%, and prisoners a prevalence of 31.4%. Common risk factors appear to be parenteral anti-schistosomal therapy, frequent transfusions, injections or surgical procedures.
Conclusion: Egypt has experienced, and possibly continues to experience, a large HCV epidemic. Prevention measures need to be implemented targeting HCV transmission routes such as better infection control practices in health and dental care facilities, hemodialysis centers, and reducing the excessive numbers of non-therapeutic injections.
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miRNA Mediated Regulation of hOrai1 Expression
المؤلفون: Rashmi Kulkarni, Nadine Abu-Kaoud and Khaled MachacaAbstractOrai1, a Calcium channel functions with STIM1, a Calcium sensor to mediate Calcium influx. Orai1 is at the plasma membrane and STIM1 localizes in a diffuse manner to the ER membrane under resting conditions. Following Ca++ store depletion, STIM1 forms puncta that localize to the cortical ER and binds Orai1 to allow Ca++ influx. This is the predominant pathway for Ca++ influx in non-excitable cells and is referred to as Store-Operated Calcium Entry (SOCE). Mutations in STIM1 and Orai1 cause severe combined immunodeficiencies and are linked to several forms of cancers. Tight regulation of the levels of members of Ca++ signaling pathways is crucial for maintaining the subcellular levels of Ca++ required for its numerous functions.
We are interested in the mechanisms that regulate some of the key players of the SOCE pathway. We have developed a system that allows us to test whether these genes are regulated by miRNAs in different cell types at different stages of the cell cycle. We are using normal human cell lines vs. human cancer cell lines to elucidate different mechanisms of regulation of these genes.
We used a GFP and the 3'UTR of hOrai1 as a transcriptional fusion to transfect HEK 293 cells and GFP without any 3'UTR as a control. As an internal control of transfection efficiency we expressed mCherry from the same vector in both conditions. We found the stoichiometry of GFP and mCherry levels in the experimental conditions for hOrai1 3' UTR to be significantly different from those in the control indicating a miRNA-mediated regulation of hOrai. We also found the ratio between GFP and mCherry to be constant throughout the cell cycle in the control and variable in the GFP hOrai1 3'UTR transfected cells suggesting a cell-cycle dependent regulation of hOrai1. We are taking a similar approach to determine whether hSTIM1 is regulated by miRNAs.
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Design of Steering Mechanism for Automated Cystoscopy
المؤلفون: Xianming Ye, Carlos Velasquez and W. Jong YoonAbstractUrinary bladder cancer is one of the most common cancers worldwide and has a high recurrence rate. It has the highest lifetime cost of care per patient due to long follow-up cystoscopic surveillance after surgery to detect the high risk of recurrence.
This research develops a portable custom cystoscopic procedure to improve the efficiency and accuracy of the bladder cancer surveillance. The system uses a segmented bending mechanism that is inserted into the bladder via the urethra to steer a flexible imaging probe to provide a comprehensive diagnostic tool for review by an urologist as illustrated in Fig. 1. The position and orientation of the camera locating at the tip of the probe can be automatically controlled remotely to scan the entire bladder surface.
The structure of the bending segment is shown in Fig. 2. The segment bending is tendon driven. Four distributed small wires are connected to the segment body via guiding rings. The wires to control the distal segments are also guided through the mechanism via the rings of proximal segments. The bending angle and bending direction of a segment can be controlled by pulling and releasing its four wires accordingly. The design of the mechanism and the forward/inverse kinematics simulation were finished. A mockup model is under construction to verify the proposed design.
Images abstracted from the video are used to reconstruct a 3D panorama of the whole bladder surface. Our 3D and image mosaicking software is under developed by our collaborator at University of Washington, USA.
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Intra and Extra Cellular Loops of hENT1 are Dispensable for the Transport of Adenosine and Uridine
المؤلفون: Jaya Aseervatham, Lucky Tran, Liu Chen, Khaled Machaca and Olga BoudkerAbstractBackground: Nucleoside transporters play an important role in regulating the extracellular concentration of Adenosine and salvaging nucleosides. They also play an essential role in the transport of anticancer and antiviral drugs. Nucleoside transporters have been classified into families known as Equiliberative (ENT) and Concentrative (CNT).
Objective:ENTs belong to the SLC 29 transmembrane protein family, with 11 transmembrane domains with intracellular N- terminus and extracellular C terminus. In order to localize to the plasma membrane they must undergo correct processing, targeting and trafficking. Constructs were designed where the intracellular and extracellular loops were deleted and used to test the efficiency of Adenosine and Uridine transport in Xenopus laevis oocytes using radiolabelled substrates.
Methods: Stage VI Xenopus oocytes were injected with 23ng hENT1 RNA, and incubated for 48 hrs at 18 degrees. 5 uM 14C-labeled Adenosine and Uridine were added to the tube containing 5 oocytes, and incubated for 1-60 min at different time intervals. Concentration dependent study was carried out at different concentrations of Uridine ranging from 100uM - 4mM. The oocytes were washed 6 times in transport buffer and lysed with 1% sodium dodecyl sulfate and counted in a Liquid scintillation counter.
Results and conclusion: Confocal images confirmed the ENT1 protein localization to the plasma membrane. The results of the time-dependent study showed that the deletions were able to transport Adenosine and Uridine, while the concentration dependent study showed no major variation in the Km for the substrates, confirming that the extra and intracellular loops in hENT1 are not essential for the transport of neither Adenosine nor Uridine.
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Role of Inositol 1,4,5-Triphosphate Receptors in Hypertension
AbstractBackground: Chronic hypertension is a deadly disease that affects nearly 30–36% of the adult population in Qatar and the regional. Inositol 1,4,5-triphosphate receptors (IP3R) are intracellular calcium (Ca2+) channels that mediate the release of Ca2+ from sarcoplasmic reticulum in response to IP3 binding. A rise in cytoplasmic Ca2+ mediated by voltage-dependent L-type Ca2+ (CaL) channels and IP3-dependent Ca2+ release can enhance vascular smooth muscle cells (VSMC) contractility and determine peripheral vascular resistance.
Objective: The goal of this study is to elucidate the role of IP3R in hypertension.
Methods: Two rat models of hypertension and the A7r5 rat embryonic aortic cells are used in this project. Proteins for western blot were isolated from small mesenteric arteries (SMA) from hypertensive rats and A7r5 cells. Contraction measurements were performed in isolated arterial rings mounted for tension-recording assays. Contraction was induced with KCl and the phospholipase C (PLC) activator m-3M3FBS. The modulation of the vasoconstrictor responsiveness of SMA by IP3R and nitric oxide (NO) was depicted in a pressurized SMA incubated in the presence or absence of 2-APB (IP3R blocker) and L-NAME (NO synthase inhibitor). A7r5 basal Ca2+ levels were assessed using a fluorescence Ca2+ imaging system.
Results: Our preliminary results show that IP3R is up regulated in SMA from two different hypertensive rat models and following membrane depolarization in A7r5 cells. This up regulation is associated with an enhanced myogenic tone in response to activation of the PLC-IP3 pathway in SMA and with an increased basal Ca2+ levels in A7r5 cells. In contrast, pharmacological inhibition of IP3R alters the vasoconstriction response of pressurized vessels. Furthermore, IP3R upregulation and basal Ca2+ increase are lost in A7r5 cells treated with Nifedipine (CaL channels blocker) and drugs that block the Calcineurin-NFAT pathway before depolarization with KCl.
Conclusions: These findings improve our basic understanding of the etiology of hypertension by defining the abnormalities of IP3-dependent Ca2+ signaling in VSMC. This may provide novel insights into the pathogenesis of hypertension and set the groundwork for developing novel therapeutic targets for the treatment of hypertension.
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Role of Oxidative Stress in Hyperglycemia Induced Endoplasmic Reticulum Stress Associated Vascular Dysfunction
AbstractBackground: The higher incidence of cardiovascular complications and the unfavorable prognosis among diabetic individuals who develop such complications has been correlated to the hyperglycemia induced oxidative stress (OS) and associated endothelial dysfunction (ED). Additionally, the Endoplasmic Reticulum (ER) stress response, otherwise known as the Unfolded Protein Response (UPR), has been implicated in hyperglycemia associated ED. However, the role of OS in hyperglycemia induced ER stress associated ED remains unclear.
Objective: The present study evaluated the role of OS in hyperglycemia induced ER stress associated ED and whether antioxidant treatment could aid in the reversal the adverse effects hyperglycemia induced ER stress and ED.
Methods: Endothelial cells (ECs) were exposed to normal (NG) and high glucose (HG) for 24 and 48hrs in the presence and absence of the anti-oxidant N-acetyl cysteine (NAC). The level of oxidative stress in the cells was analyzed by DCFDA fluorescence staining levels of ER stress proteins GRP78, PERK and IRE1 were analyzed by immunoblotting.
Results: DCFDA staining indicated that OS significantly increased in HG exposed ECs while this effect was reversed upon in NAC treated endothelial cells. ER stress was significantly increased in HG treated cells as indicated by the changes in the level of ER stress proteins.
Conclusion: The data suggests that hyperglycemia induced OS plays a major role in ER stress and associated ED. Amelioration of OS by suitable antioxidant treatment may be used as therapeutic target for the treatment of diabetes associated cardiovascular diseases. However, more studies are warranted on the choice and dosage the of anti-oxidant, time of administration and supplementation of the anti-oxidant, duration of therapy and choice of treatment subjects to further evaluate the efficacy of anti-oxidant therapy in the treatment of cardiovascular conditions associated with diabetes.
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Variegated Gene Activation and Stochastic Odorant Receptor Choice
المؤلفون: Benjamin ShykindAbstractEach olfactory sensory neuron in the mammalian nose selects just a single member of the large odorant receptor (OR) gene family. The core processes regulating OR selection may involve mechanisms that limit initial OR transcription and once a single OR is chosen, repress subsequent activations. We have used a genetic strategy to monitor the transcriptional permissiveness of the OR gene P2 by inserting an exogenous promoter, the tetracycline-dependent transactivator responsive promoter (teto), into its start site through homologous recombination. We observe that the OR locus limits the expression of the teto: repressing it outside of the wild type P2 zone while allowing sporadic activation from within its zone. Staged conditional expression experiments reveal that the receptor locus becomes fully repressed over time and that this repression does not require the receptor's open reading frame. Further, the exogenous promoter is inhibited by an OR transgene that similarly suppresses the endogenous receptor repertoire. Neurons in which both P2 alleles bear the teto-modified insertion show predominantly monoallelic expression, despite the genetic potential to express both. Finally, we observe that OR genes are expressed from the edge of pericentromeric heterochromatin. These data support a model of initiation of OR choice limited by non-permissive OR chromatin and maintained by repression of the non-selected OR genes.
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Biogenesis of the Store Operated Ca 2+ Channel, Orai1
المؤلفون: Nasrin Mesaeli, Abdelilah Arredouani, Hamid Massaeli, Mashael Al Shafai and Khaled MachacaAbstractBackground: Ca2+ plays an essential role as a second messenger regulating many cellular functions including gene regulation and enzyme activity. Thus intracellular Ca2+ concentration is tightly regulated. Store operated Ca2+ channel (SOC) is a plasma membrane channel, which is activated upon depletion of endoplasmic reticulum (ER) Ca2+. This channel is compromised of two proteins STIM1, that is localized to the ER membrane and senses luminal Ca2+ concentration, and Orai1, that forms the channel at the plasma membrane. To date little is known about the synthesis and maturation of Orai1 protein. Calreticulin and calnexin are two lectin-like chaperones in the ER, which are involved in the synthesis and maturation of many membrane and secretory proteins. In addition to its chaperone function, calreticulin binds Ca2+ with high capacity and low affinity and regulates intracellular Ca2+ homeostasis. Previously, we showed that loss of calreticulin function activates ER stress pathways leading to the activation of the ubiquitin-proteasome pathway.
Objectives: To determine the role of ER chaperones in the biogenesis of Orai1.
Methods: Wild type, calreticulin deficient (crt-/-), calnexin deficient (cnx-/-) and CHO cells were used for measurement of Store Operated Ca Channel activity. Cells were transfected with EGFP-HA-Orai1 cDNA to examine the localization of Orai1 using immunocytochemistry and live cell imaging using confocal microscopy.
Results: Our data illustrates that loss of calreticulin function, but not calnexin, results in a significant decrease in the SOC activity. There was no significant change in the total Orai1 and STIM1 protein level in calreticulin deficient cells as was determined by Western blot analysis. Interestingly, loss of calreticulin function resulted in the accumulation of EGFP-HA-Orai1 protein intracellularly, which explains the decrease in SOC activity. We further demonstrate that inhibition of the ubiquitin-proteasome pathway enhances SOC activity in calreticulin deficient cells and show for the first time that Orai1 is ubiquitinated in different cell types.
Conclusions: Calreticulin, but not calnexin, function as the chaperone regulating proper maturation of Orai1 protein.
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New Identified Genetic Variants are Proven to be Associated with Breast Cancer Susceptibility and Aggressiveness in the Tunisian Population
AbstractBackground: Single nucleotide polymorphisms (SNPs) may be causally related to breast cancer risk or be indirectly associated with breast cancer risk through linkage disequilibrium with a causal sequence variant. Risk-associated SNPs will have different frequencies among women with or without breast cancer and can be detected using genetic association studies. Recently, several genome-wide association studies (GWAS) have identified novel risk alleles for breast cancer including those related to FGFR2, TNRC9, MAP3K1, LSP1 genes and other locus. Replication in independent population samples is essential for validation of the results of any genome-wide association. Since the genetic variants (SNPs) are common, they are likely to be shared across different populations with diverse ancestry backgrounds. It would be of interest to determine and investigate the potential implications of these novel markers revealed by genome-wide association studies to predict the “sporadic” breast cancer risk and progression in MENA populations.
Methods: Using TaqMan® SNP genotyping assays, we characterize the variation of 9 SNPs (include rs1219648, rs2981582, rs8051542, rs12443621, rs3803662, rs889312, rs3817198, rs13387042 and rs13281615) for 520 patients with sporadic breast cancer and 360 healthy controls in the Tunisian population. The association between the genotypes and breast cancer susceptibility and tumors characteristics was estimated by computing odds ratio (OR) and 95% confidence levels from logistic regression analyses. Association of the genetic marker with the rates of breast cancer overall survival was assessed using univariate analysis.
Results: Two genetic variants in FGFR2 are significantly associated with the risk of breast cancer: rs1219648 AG/GG (OR=1.23, P=0.002) and rs2981582 AG/ AA (OR=1.33, P=0.003). Two significantly increased risks of breast cancer were respectively associated with T allele of rs8051542 in TNRC9 (OR=1.43, P=0.0003) and C allele of rs889312 in MAP3K1 (OR=1.33, P=0.006). The AG and GG genotypes of rs2981582 in FGFR2 have a significant association with a high risk of lymph node metastasis and a decreased overall survival in breast cancer patients.
Conclusion: Our results for the first time replicated the results of breast cancer GWAS in the Arabic population and indicated that some polymorphisms are associated with increased breast cancer risk and disease progress in the Tunisian population.
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The Association of Adiponectin Gene Variants rs2241766 [+45T/G] and rs1501299 (276G > T) in Arab Patients Presenting with Acute Coronary Syndrome
المؤلفون: Ayman El-Menyar, Nasser Rizk, Isra Marei and Jassim Al SuwaidiAbstractBackground: Adiponectin is a fat derived hormone, known to decrease in type-2 diabetes (DM) and coronary artery disease (CAD). Moreover, our previous study showed that total adiponectin and its HMW isoform decreased in acute coronary syndrome (ACS) patients compared to healthy controls. The adiponectin gene ADIPOQ is located on chromosome 3q27. Two single nucleotide polymorphisms (SNPs) (rs1501299 and rs2241766) in ADIPOQ gene and their possible associations with ACS were investigated among Arab patients resident in Qatar.
Methods: A case-control association study was performed on 142 (ACS) Arab patients and 115 Arab healthy controls from Qatar. Genotypes were determined using TaqMan real time PCR assay. Serum adiponectin level was determined using ELISA.
Results: The GG, GT and TT genotype frequencies of the rs2241766 [+45 T/G] variant showed significant difference between the control and (ACS) cases (45.2%, 40.0%, 14.8% vs. 46.2%, 25.0%, and 28.8%, p=0.0001), respectively. In contrast, there was no significant association between the control and (ACS) cases in the GG, GT and TT genotype frequencies of the rs1501299 (276G > T) (39.8%, 49.1%, 11.1% vs. 41.7%, 48.3%, and 10.0%, p=0.94), respectively. T allele was the minor allele for both rs2241766 and rs1501299 with a frequency of (0.31) and (0.25) respectively. All allele frequencies were in equilibrium for HWE among study subjects [P=0.51] for SNP rs2241766 and (p=0.12) for rs1501299. Using logistic regression analysis with adjustments of age and body mass index, only the T allele of rs2241766 variant was significantly associated with risk of (ACS) with odds ratio of 2.430, (95% of CI 1.010–5.563) with the (p= 0.047) among subjects using the genetic dominant model.
Furthermore, using dominant genetic model, linear regression analysis showed an inverse significant association between the SNP rs2241766 (+45T>G) in the adiponectin gene and serum adiponectin levels (r=−0. 621,p<0.001) among all subjects. By contrast, no significant association was found between rs1501299 (276G > T) and adiponectin level.
Conclusion: This study suggests that rs2241766SNP (+45T>G) in the adiponectin gene is associated with high risk for ACS, and has an effect on the serum adiponectin levels among Arab populations.
Study Supported by UREP(4-3-42),QF & MRC,HMC.
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Molecular Signature of Human Brown Adipocyte-Like PAZ6 Cells
المؤلفون: Mouaadh Abdelkarim, Virginia Takahashi, Smitha Kota, Donny Strosberg and Lotfi ChouchaneAbstractBackground: Prevalence of metabolic syndrome is directly correlated with increasing occurrence of obesity characterized by accumulation of fat in visceral, lower body, and upper body subcutaneous depots. In a number of species, brown adipose tissue (BAT) converts triglycerides into heat by non-shivering thermogenesis, thus controlling the amount of white adipose tissue. Until recently, BAT was thought to be mostly absent in adult humans but now sizeable BAT depots have been visualized by Positron Emission Tomography (PET) and Computed Tomography (CT) scanning. Relatively little is known about the signaling pathways differentially regulated in brown adipocytes compared to white adipocytes. However, our progress of understanding is hindered by the paucity of well-characterized reliable in vitro model systems.
Objectives: The aim of this study is to characterize the only in vitro model of human BAT cell line, and to identify signature genes for BAT, and compounds implicated in the enhancement of brown phenotype.
Methods: A human BAT cell line, PAZ6, was previously created by immortalizing somatic cells using the large T antigen of Simian Virus 40. The expression of BAT associated markers has been verified by real time RT-PCR done on RNA and immunoblot using specific antibodies performed on cell lysates and supernatants, before and after differentiation and treatment with various compounds such as adrenergic receptor agonist (isoproterenol) and PPAR agonist (rosiglitazone).
Results: We have identified several BAT associated markers, including PDRM16 and the 3 adrenergic receptor. This marker is highly expressed in PAZ6 cells compared to the white adipocyte. In addition, we demonstrate that these cells share a common precursor with myocytes but not with white adipocytes. Our results show that several genes are up-regulated after PPAR gamma activation. Moreover, we confirm that these cells respond to Beta adrenergic agonist treatment. Finally, we identify that the transcription factor farnesoid X Receptor (FXR) induces the expression of BAT associated marker following treatment by its agonist : CDCA.
Conclusions: The PAZ6 cells constitute a readily available surrogate for human brown adipocytes to develop pharmacologic strategies to promote BAT expansion and activation.
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The Genetic Basis of Human Metabolic Individuality and its Role in Complex Diseases
المؤلفون: Karsten SuhreAbstractGenome-wide association studies (GWAS) have identified many risk loci for complex diseases, but effect sizes are typically small and information on the underlying biological processes is often lacking. Associations with metabolic traits as functional intermediates can overcome these problems and potentially inform individualized therapy. Here we report a comprehensive analysis of genotype-dependent metabolic phenotypes using a GWAS with non-targeted metabolomics. We identified 37 genetic loci associated with blood metabolite concentrations, of which 25 show effect sizes that are unusually high for GWAS and account for 10–60% differences in metabolite levels per allele copy. Our associations provide new functional insights for many disease-related associations that have been reported in previous studies, including those for cardiovascular and kidney disorders, type 2 diabetes, cancer, gout, venous thromboembolism and Crohn's disease. This study advances our knowledge of the genetic basis of metabolic individuality in humans and generates many new hypotheses for biomedical and pharmaceutical research. This work was recently published with contributions from WCMC-Q (Suhre et al., Nature 2011, http://www.dx.doi.org/10.1038/nature10354). After a general presentation of the results I shall focus on the relevance of this work for future research in Qatar.
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Systems Approach Towards Diabetes Research Using Molecular profiling Tools
المؤلفون: Amrita K Cheema and Nasser RizkAbstractThe prevalence of insulin resistance and diabetes has shown a dramatic worldwide increase. In Qatar, the prevalence of diabetes is twice that of the United States today, possibly due to lifestyle and dietary changes. Diabetes has an enormously adverse impact on the afflicted population leading to patient mortality, morbidity and staggering health care costs to the nation. Untreated or inadequately treated diabetes results in serious health complications including eye, heart, kidney and nerve damage.
Mass spectrometry based molecular profiling is a powerful tool for interrogation of the underlying molecular alterations which define the etiology and patho-physiology of a complex disease such as diabetes. As a part of the QNRF funded study, we have used ultra performance liquid chromatography (UPLC) in conjunction with high resolution quadrupole time of flight mass spectrometry (Q-TOFMS) for proteomic and metabolomic profiling of bio-fluids derived from diabetic and healthy individuals recruited at the Qatar University Hopsital. The overall goal of this project was to investigate the changes in the molecular profiles in the two groups (normal and diabetic) at the protein and small molecule metabolite level and correlate these changes to define putative biomarkers with potentially diagnostic or prognostic clinical value. We have used a “smart pooling strategy” for bio-fluids from each group to enhance disease associated differences. LCMS/MS based metabolomic analysis of the diabetic and normal pre and post meal metabolome was followed by bioinformatics analysis to identify dysregulated metabolites. Additionally, we have used iTRAQ based UPLC-QTOFMS/MS for quantitative proteomic profiling.
These data were taken together for integrated functional pathway analysis to correlate the changes. Furthermore, we have used a validation cohort for targeted quantitation of candidate markers using multiple-reaction monitoring mass spectrometry. The results will be discussed in context of the state of art technology used for studying pathway perturbations resulting in a diabetic phenotype. A part of this study reported at the HUPO2010, won a “young investigator award” for Dr. Cheema. The ARF presents a unique opportunity to present results from this exciting study, deliberate upon the challenges faced and elaborate on the plans for future studies aimed at a mechanistic insight.
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Elevated Myocardial Na+/H+ Exchanger Isoform 1 Induces Cardiac Hypertrophy and the Upregulation of Osteopontin Gene Expression
المؤلفون: Fatima Mraiche, Larry Fliegel, Jin Xue and Gabriel G. HaddadAbstractCardiac hypertrophy (CH), a prominent feature that predisposes the heart to failure, is associated with the activation of multiple molecular and cellular changes in the circulation and heart. The Na+/H+ exchanger isoform 1 (NHE1) has been implicated in the development and progression of CH. To better understand the involvement of NHE1, transgenic mice that express cardiac specific active NHE1 expression were studied. N-line mice expressed wild-type NHE1, and K-line mice expressed activated NHE1. NHE activity of adult ventricular cardiomyocytes and protein expression were elevated by approximately 2 and 3-fold in the N- and K-line mice vs. control. The K-line mice assessed by echocardiography demonstrated significant global cardiac dysfunction. Left ventricular fractional cell shortening and ejection fraction were significantly decreased in the K-line mice (23.1 ± 3.8% and 45.2 ± 6.9% K-line vs. 36.5 ± 1.1% and 66.4 ± 1.5% control, respectively; p<0.05). The K-line mice also exhibit myocardial remodeling. The heart weight to body weight ratio was significantly greater in the K-line mice (143 ± 10.0% of control; P<0.05). Cross sectional area (K-line 195.6 ± 16.4% of control; p<0.05) and interstitial fibrosis (K-line: 275.4 ± 11.6% of control; p<0.05) were also elevated. Genechip analysis also revealed that expression of active NHE1 upregulated osteopontin (OPN) gene expression (>1,500 fold change) and its signaling pathways. OPN is a matricellular protein and a cytokine induced upon tissue injury and remodeling of various organs, including human heart failure (HF). Our study shows that expression of activated NHE1 induces CH and elicits specific molecular changes that lead to CH.
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Muscle Mechanical Determinants of Sprint Performance Across the Professional Life-Span in Soccer Players
المؤلفون: Dino Adriano Palazzi and Jose Alberto Mendez-VillanuevaAbstractBackground: The functional relevance of strength and power measures as an index of functional performance (i.e., sprinting speed) in soccer remains unclear.
Objective: The aim of this study was to investigate the relationships among mechanical variables related to strength and power tests and their influences on sprinting speed in professional soccer players across their life-span.
Methods: Isokinetic measures (quadriceps (Q) peak torques and power at 60°/s and 300°/s), kinetic outputs of the counter-movement jump (CMJ), and sprinting speed (the first 5 m split time (i.e., initial speed) and the 15 to 20 m split time (i.e., leading sprint) of a 20 m sprint), were measured in 224 professional soccer players (age 23.7 ± 4.4 y, body mass 71.4±8.8 kg and height 1.75±0.06 m).
Results: The values for each variable for the fast and slow groups are displayed in Table 1. All the mechanical variables were significantly different between the fast and slow players regardless of the results were ranked according to 5 m or 15–20 m times. The results of the multiple regression analyses identified CMJ height as the best predictor of sprinting performance for the 5 m (R=0.39, P=0.000) and 15–20 m (R=0.51, P=0.000) sprint.
Conclusions: All the mechanical variables could discriminate between the fast and slow players. However, a great degree of unexplained variance still remains indicating there may be better mechanical predictors of sprinting speed in soccer players.
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