Qatar Foundation Annual Research Forum Volume 2013 Issue 1
- تاريخ المؤتمر: 24-25 Nov 2013
- الموقع: Qatar National Convention Center (QNCC), Doha, Qatar
- رقم المجلد: 2013
- المنشور: ٢٠ نوفمبر ٢٠١٣
161 - 180 of 541 نتائج
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High-throughput screening technology for anti‐diabetic drug discovery based on adiponectin receptors
المؤلفون: Mustapha AouidaThe anti‐diabetic and insulin‐sensitizing effects of adiponectin, a hormone secreted by adipose tissue, are mediated by its molecular interactions with the plasma membrane receptors AdipoR1 and AdipoR2. Adiponectin occurs in several molecular forms and each of these forms has a specific signaling outcome that also depends on the relative abundance of the two receptors. The complex interactions between adiponectin and its receptors are poorly understood. A detailed characterization of how adiponectin interacts with its receptors and, in turn, how these receptors transmit specific downstream signals is critical for the development of meaningful therapeutic interventions for a wide spectrum of metabolic disorders (including type 2 diabetes, obesity, and inflammatory bowel disease) and cancers (of the breast, colon and prostate), all of which are known to be associated with adiponectin function. Here, we report a Saccharomyces cerevisiae based method for investigating agonist-AdipoR interactions that is amenable for high-throughput scale-up and can be used to study both AdipoRs separately. Agonist-AdipoR1 interactions are detected using a split firefly luciferase assay based on reconstitution of firefly luciferase (Luc) activity due to juxtaposition of its N- and C-terminal fragments, NLuc and CLuc, by ligand induced interaction of the chimeric proteins CLuc-AdipoR1 and APPL1-NLuc (adaptor protein containing pleckstrin homology domain, phosphotyrosine binding domain and leucine zipper motif 1-NLuc) in a S. cerevisiae strain lacking the yeast homolog of AdipoRs (Izh2p). The assay monitors the earliest known step in the adiponectin-AdipoR anti-diabetic signaling cascade. We demonstrate that reconstituted Luc activity can be detected in colonies or cells using a CCD camera and quantified in cell suspensions using a microplate reader. AdipoR1-APPL1 interaction occurs in absence of ligand but can be stimulated specifically by agonists such as adiponectin and the tobacco protein osmotin that was shown to have AdipoR-dependent adiponectin-like biological activity in mammalian cells. To further validate this assay, we have modeled the three dimensional structures of receptor-ligand complexes of membrane-embedded AdipoR1 with cyclic peptides derived from osmotin or osmotin-like plant proteins. We demonstrate that the calculated AdipoR1-peptide binding energies correlate with the peptides' ability to behave as AdipoR1 agonists in the split luciferase assay. Further, we demonstrate agonist-AdipoR dependent activation of protein kinase A (PKA) signaling and AMP activated protein kinase (AMPK) phosphorylation in S. cerevisiae, which are homologous to important mammalian adiponectin-AdipoR1 signaling pathways. This system promises to be an effective tool for the identification of novel pharmaceutically active AdipoR agonists and should facilitate the development of therapeutic inventions targeting adiponectin and/or AdipoR physiology.
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Change in the structure, dynamics and disease-related mortality rates in the population of Qatari nationals: 2007 - 2011
المؤلفون: Alaa BadawiBackground: Developing effective public health policies and strategies for interventions necessitate an assessment of the structure, dynamics, disease rates and causes of death in a population. Lately, Qatar has undertaken development resurgence in health and economy that resulted in improving the standard of health services leading to enhanced life expectancy as was evident in the entire Qatari population (i.e., Qatari nationals and non-Qatari residents). No study has attempted to examine the influence of improving the health services on the homogenous, stable population of Qatari nationals. Objective: The present study examines the population structure and dynamics and the related changes in the cause-specific mortality rates and disease prevalence in the Qatari nationals. Methods: This is a retrospective, analytic descriptive analysis covering a period of 5 years (2007-2011) and utilizes a range of data sources from the State of Qatar including the population structure, disease-related mortality rates, and the prevalence of a range of chronic and infectious diseases. Factors reflecting population dynamics such as crude death (CDR), crude birth (CBR), total fertility (TFR) and infant mortality (IMR) rates were also calculated. Results: The Qatari nationals is an expansive population with an annual growth rate of ~4% and a stable M:F ratio. The CDR declined by 15% within the study period whereas the CBR was almost stable. The total disease-specific death rate, however, was decreased in the Qatari nationals by 23% due to the decline in mortality rates attributed to diseases of the blood and immune system (43%), nervous system (44%) and cardiovascular system (41%). There was a high prevalence of a range of chronic diseases whereas very low frequencies of the infectious diseases within the study population. Conclusion: Public health strategies, approaches and programs, developed to reduce diseases burden and the related death, should be tailored to target the population of Qatari nationals since this population exhibits characteristics that vary from the entire Qatari population.
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Diabetes awareness and prevention: A lifestyle based pilot program in Qatar schools
المؤلفون: Sohaila CheemaAbstract Diabetes is widely prevalent in the Middle East. Its incidence and prevalence are on the rise in the Gulf Cooperative Council (GCC) nations. In Qatar, the World Health Organization estimates that diabetes accounts directly for 7% of total deaths, while cardiovascular diseases account for 23% [1], both of which are related to lifestyle factors. Risk factors for diabetes are fairly well established. But it is worrisome that they are becoming more prevalent. However, it is reassuring to know that the disease can be prevented or its onset delayed by adopting healthy life style factors. Examples of these factors include healthy diet and adequate physical activity [2]. The World Health Organization has identified that "Education is a cornerstone of diabetes care and prevention" [2]. Thus, providing education to all segments of society is imperative. It is well recognized that lifestyle habits conducive to good health are formed in childhood and adolescence [3]. Therefore, educating children and adolescents about healthy lifestyles and implementing diabetes prevention programs in primary and secondary schools will yield not only short-term but also long-term benefits. We have, thus, developed a school education program with its target group of secondary school children in the 15-18 year age range. The program will be rolled out in selected Qatari schools, and will provide information to students on topics of importance in the prevention of diabetes. The interactive program will encourage student participation. Outcomes will be measured using Knowledge, Attitude and Practice tools both pre- and post-intervention. Change in knowledge and attitudes will be evaluated through written and oral methods of assessment. We will discuss the program objectives, its format, content and evaluation. Evaluation findings will be presented and discussed. The findings will enable us to determine the effectiveness of the program. References 1. World Health Organization - NCD Country profiles, 2011 2. Awareness of Prediabetes — United States, MMWR 2005-2010 Weekly, March 22, 2013 / 62(11); 209-212. (http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6211a4.htm) 3. National Institutes of Health. http://www.nhlbi.nih.gov/health/health-topics/topics/hd/prevent.html (downloaded July 28, 2013) Acknowledgement: This work is supported and funded by the Office of Academic Health System at Hamad Medical Corporation.
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Clolrectal cancer (CRC) and cancer precursor lesions (adenomas) in the young average risk population of Qatar
المؤلفون: Manik SharmaBackground: The incidence of Colorectal Cancer (CRC) peaks in the sixth and seventh decade of life and its precursor lesions a decade earlier in average risk population. American College of physicians (ACP) recent guidelines suggests CRC screening at 50 years of age and older in average risk persons to detect and treat colorectal cancer precursor lesions and early cancers. Objective: To delineate the incidence of Colorectal Cancer (CRC) and Cancer Precursor Lesions (CPL) in the 30 - 49 years age group in symptomatic and asymptomatic average risk population of Doha, Qatar. Method: Lower gastrointestinal endoscopies are routinely done in Qatar for diagnosis and treatment for patients presenting with lower abdominal pain, bleeding or worsening constipation. A retrospective collection of data was done to know the incidence of CRC and CPL among all the patients reporting to our hospital with above mentioned symptoms. Based on the results of this data, a cut off age was calculated with highest sensitivity and specificity for detection of CPL. A CRC screening program was then initiated among asymptomatic subjects with positive immunological fecal occult blood (iFOBT) and age > 40 years were invited for screening colonoscopy. Incidence of CPL (colorectal adenomas) and CRC was calculated prospectively in the average risk asymptomatic population among various age groups. Data regarding the incidence of CRC and CPL among symptomatic and asymptomatic (screened) population was compared. Results: A total of 1489 lower gastrointestinal endoscopies were done in symptomatic patients over a one year period. The mean age was 47.5 years, 935 were males with 71.3 % being expatriates. Overall, among the symptomatic people, CPL were detected in 14.5 % (n= 216) and CRC in 5.6 % (n= 84).Of these, CPL and CRC was detected in 22.6 % (n= 49) and 34 % (n=29) respectively in the age group of 30-49 years. Among the asymptomatic 1242 people who participated in the CRC screening keeping a cut-off age of > 40 years, 57 people (4.6%) were found to be positive for occult blood in stool. Of them, seven and five patients were detected to have CPL and CRC respectively between the age group of 40-74 years. In the 30-49 years age group, CPL was detected in 14.3 % (n=1) but without any CRC. Table 1. Conclusion: One-third of cancers (34%) and one-fifth of cancer precursor lesions (22 %) are detected in the 30-49 years age group in symptomatic patients in Qatar. Among the young (fourth decade of life) asymptomatic subjects, the incidence of cancer precursor lesion remains similar to symptomatic patients but without any obvious cancer. Hence, it is recommended that young symptomatic patients should undergo lower endoscopy early to detect cancer and cancer precursors. Larger studies are required in the asymptomatic subjects of 40-49 years age group to estimate the incidence of pre-cancerous lesions that might benefit from CRC screening.
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Endothelial cells provide a niche for placental hematopoietic stem/progenitor cell expansion through broad transcriptomic modification
المؤلفون: Christophe RaynaudUmbilical cord blood (UCB) is an attractive source of hematopoietic stem cells (HSCs). However, the number of HSCs in UCB is limited, and attempts to amplify them in vitro remain inefficient. Several publications have documented amplification of hematopoietic stem/progenitor cells (HSPCs) on endothelial or mesenchymal cells, but the lack of homogeneity in culture conditions and HSC definition impairs direct comparison of these results. We investigated the ability of different feeder layers, mesenchymal progenitors (MPs) and endothelial cells (ECs), to amplify hematopoietic stem/progenitor cells. Placental derived HSPCs (defined as Lin-CD45-/dimCD34+CD38-CD90+) were maintained on a confluent feeder layers and the number of cells and their marker expression were monitored over 21 days. Although both types of feeder layers supported hematopoietic expansion, only endothelial cells triggered amplification of Lin-CD45-/dimCD34+CD38-CD90+ cells, which peaked at 14 days. The amplified cells differentiated into all cell lineages, as attested by in vitro colony-forming assays, and where capable of engraftment and multi-lineage differentiation in sub lethally irradiated mice. Mesenchymal progenitors promoted amplification of CD38+ cells, previously defined as precursors with more limited differentiation potential. A competitive assay demonstrated that hematopoietic stem/progenitor cells had a preference for interacting with endothelial cells in vitro. Cytokine and transcriptomic analysis of both feeder cell types identified differences in gene expression that correlated with propensity of ECs and MPs to support hematopoietic cell amplification and differentiation respectively. Finally, we used RNA sequenencing of endothelial cells and HSPCs to uncover relevant networks illustrating the complex interaction between endothelial and HSPCs leading to stem/progenitor cell expansion.
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The development of analytical measurements for point of care testing in chronic wound healing
المؤلفون: Stephen MilneIn recent years a specialist interest has developed worldwide in Advanced Wound Management for difficult to heal chronic wounds. This is timely given the increasing number of elderly in the population and the growing burden of diabetes, obesity and cardiovascular disease that all contribute to an increase in hard to heal wounds. Further progress in Advanced Wound Management will require an improvement in personalised medicine for the patient and in particular an improvement in the availability of diagnostic tests and parameters that fulfil clinical need in wound management decisions. At the current time in wound care there is little available in near patient testing for clinical diagnostics. This research project focuses on a number of metrics for wound condition and wound healing: wound moisture, wound fluid pH, and wound matrix metalloproteinases (MMP) enzyme activity. To observe these important markers a state of the art sensor for wound moisture monitor is being deployed in clinical studies and new sensors are currently in development for both pH and MMP-9 enzyme level. Moisture levels in wounds can determine how well a wound heals and in addition it is possible to make decisions on the need for dressing changes based upon moisture readings taken from inside the dressing. The pH of a wound can affect many different phases of the healing process such as oxygen levels, cell proliferation, protease enzyme activity and bacterial growth. If the pH level of a wound can be effectively monitored then it can act as a biological marker to aid in diagnostics and in establishing the optimum conditions for healing. The pH electrode has not been successfully adapted into smaller and alternate packaging because the membrane that forms the selective part of the electrode, being made of silicon glass, is fragile, thus limiting manufacture, sterilisation and practical application. A disposable sensor has been produced through a screen printing method with an ion-selective membrane. The sensor is able to detect the pH in an operational range in the pH 3.5-10 with as little 10µL of fluid. MMPs are involved in every phase of wound healing. If the balance of the MMPs is upset within a wound it can upset the cellular processes preventing healing and eventually causing further damage to the wound. In chronic wounds the amount of MMP-9 activity has been found to be 30 times more than in acute wounds. By measuring the MMP-9 level of a wound the clinician will be able to choose treatment appropriately to return the MMP level to optimum healing conditions. The project has developed an assay for measuring MMP-9 at physiologically relevant levels between 0.01-100ng/ml. These sensors will enable the wound healing markers of moisture, pH and MMP enzyme activity to be studied and profiled in Hamad Medical Corporation which will further the understanding of these markers and their relationship in the complex healing process involved in chronic wound healing.
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Homogeneous Deformation Of Internally Balanced Compressible Hyperelastic Materials
المؤلفون: Ashraf HadoushIt is common nowadays to implement principles of continuum mechanics to describe the behavior of advance engineering materials. Continuum mechanics take into account the mapping of material pointsXdescribed in reference (undeformed) configuration into x described in current (deformed) configuration due to action of physical factors e.g. force or heat. The gradient of this mapping is denoted by F. It is common to model the behavior of the material in terms of stored energy function that for hyperelastic material expressed in terms of F; W(F). In practice, material behavior may consist of elastic response combined with some other type of nonelastic response such as plastic flow or biological growth. Therefore, it is common to decompose the deformation gradient at each material point such as F = F^ . F* (1) where F^ is elastic response and it is determined by the rules of variational calculus. The nonelastic response F is subjected to some kind of time dependent evolution law. Pence et al. (2013) have introduced a radically new way of viewing material using this concept. Actually, they consider the case where arguments of variational calculus apply to both factors and can be used to determine the decomposition itself. Preliminary indications is that this will offer great benefit in the modeling of complex material especially as regards to the development of singular surfaces that can be interpreted as locations of concentrated microstructural rearrangement. The extension of this internally balanced material models to include compressible hyperelasticity is investigated Hadoush et al. (2013). In this work the homogeneous deformation; dilatation, uniaxial and simple shear are examined for the two special cases of Blatz-Ko material model. It is found that the new theory retrieves conventional hyperelasticity for certain limiting cases.
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Distribution and factors associated with predominance of Salmonella enterica serovars in humans and animals using multi-locus sequence typing in Qatar
المؤلفون: Hussni MohammedBackground and Objectives-Salmonella enterica is one of the most commonly reported causes of bacterial foodborne illness around the world. Many factors, including food of animal sources, play a role in the predominance of certain serovars. The occurrence of S. enterica serovars varies between different geographical regions and data on their occurrence in Qatar is lacking. Knowledge on the occurrence of zoonotic serovars and associated factors will help to design cost-effective risk mitigation strategies. This risk of salmonellosis has been exacerbated by the ease of travel around the world, increase in world trade of food and animal items, and continued migration of people. Qatar is one of the countries where the factors that exacerbate the risk of foodborne diseases intersect. We carried out a combination of epidemiologic and molecular studies to investigate the distribution of S. enterica serovars in this highly diverse population, and to identify the factors that play a role in the predominance of a particular serovar. Methods-We carried out a repeat cross-sectional study in which human and non-human samples were collected and Salmonella spp. were detected using a combination of bacterial enrichment and real-time PCR. Salmonella isolates were analysed using the Multi-locus sequence typing (MLST) scheme and assigned accordingly by their eBURST groups (eBGs). We used the minimal spanning tree (MST) analysis to investigate the relationship among the isolates from different sources. Data on putative risk factors were collected and analysed for significance of association with particular serovars. Results-We identified 27 different sequence types (STs) and the most common were ST11 (29.5%) and ST19 (11.5%). Among the 27 STs, seven were novel (ST1695, ST1696, ST1697, ST1698, ST1699, ST1702, and ST1703). The STs related to serovar Enteritidis were ST-11, ST1695, and ST-1702; to Typhimurium were ST-15, ST-19, and ST-568; and to Newport were ST-31, ST-808, and ST-1698. Three of them were revealed to be common serovars in this study. In the MST analysis, three major clusters were presented in the overall population: Enteritidis, Newport and Typhimurium. Furthermore, it also revealed the possibility of transmission of strains between human and animal sources according to the lineages of STs. It was more likely to detect serovar Enteritidis in Qataris and serovar Typhimurium in non-Qataris in this study population. Conclusions—A diverse set of serovars were identified among the samples which could be due to the large scale of emigration and importation of animal feed and products in Qatar. Overall, our data also reveals the possibility of transmission of Salmonella isolates between human and animals; however, a detailed analysis of larger sample over a longer period of time using whole genome sequencing (WGS) could help to shed more light on the dynamics of transmission between these populations.
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Characterisation And Modelling Of In-Vivo Radio Propagation
المؤلفون: Qammer AbbasiRemote monitoring of patient vital signs either in hospital or in home provides ease to both patient and hospital staff. It results in less visits of patient to hospital, lesser likelihood of measurements errors, while recording vital sign information. Moreover, due to the rapid ageing in our society, continuous monitoring of the critical patient in home health care is also increasing. Recent progresses in biomaterials, biosensors, wireless communications, and electronic technologies have opened the possibility for designing remote health monitoring devices and technologies. Tracking in real-time the information provided by body surface and internal sensors helps also reduce the invasiveness of a number of medical procedures such as surgeries, internal delivery of drugs, monitoring the status of human organs, etc. The idea of deploying Wireless Body Area Networks (WBANs) which consists of low-powered sensors and actuators deployed around the human body to enable ubiquitous healthcare by measuring continuously all the physiological data of interest and releasing at the right times the necessary drugs into the body, has received considerable attention [1]. However, implementation of the remote healthcare vision comes with many challenges. One of the most important challenges is the characterization and modelling of the in-vivo wireless communication channels, since the health information must be collected from the sensors implanted inside the human body and transmitted wirelessly to the nearby hospital. The characteristics of in-vivo channel are different from wireless free-space communication channel and are due to the fact that the electromagnetic waveforms are propagating through different media that exhibit totally different electrical properties, the wave propagation speed being significantly reduced in organs relative to free space and presenting different time dispersion coefficients for different organs and body tissues. Also, the far field assumption used to develop channel models for classical RF wireless communications systems will have to be removed and the total electromagnetic field effects including the near-field effects will have to be taken into account due to the proximity of body and its organs to antenna near fields. Understanding the characteristics of in vivo communications channels will help in optimizing the physical layer signal processing and communications techniques, and designing efficient networking protocols that ultimately will make possible the deployment of wireless body area networks and remote health monitoring platforms. In this work, modeling of the in vivo communication channel is presented which involves, parametric and non-parametric channel models based on simulation and measurements. The simulations were carried out by placing a patch antenna inside the chest of the human body model and by transmitting a continuous wave signal at industrial scientific and medical (ISM) band. The receiver antenna was placed at 4 cm from the internal antenna and in the same planar height as the transmit antenna as shown in Fig. 1. References: [1] S. J. Devaraj and K. Ezra, "Current trends and future challenges in wireless telemedicine system," in Electronics Computer Technology (ICECT), 2011 3rd International Conference on, 2011, vol. 4, pp. 417-421.
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Prevalence Of The Cytolethal Distending Toxin Gene In Foodborne Pathogens Isolated From Animals And Humans In Qatar
المؤلفون: Hussni MohammedBackground and objectives-Foodborne illness has been determined to be one of the major limitations to the advancement of world health and with the ease of travel around the world and the increase in trade of food and animal products, the risk has been exacerbated in recent years. It has been proclaimed as one of the high priority issues in the Qatar National Food Security Master Plan. Different estimates of burden of disease consistently indicate a high cost per episode, irrespective of the country where the study is conducted. The mechanism by which foodborne pathogens cause disease is complex and the cytolethal distending toxin (CDT) has been identified as one of the virulence factors that contributes to gastroenteritis. The CDT is a trimeric subunit toxin produced by gram-negative bacteria that causes cell-cycle arrest and causes affected cells to die by apoptosis. In an effort to understand the mechanisms by which foodborne pathogens put humans at risk of chronic gastroenteritis sequelae, this study investigated the occurrence of the CDT among Salmonella spp., Escherichia coli serogroups and Campylobacter spp. isolates recovered from animals and humans in Qatar. Methods—Samples collected from animals and humans were screened for the presence of these three foodborne pathogens using a combination of bacterial enrichment and molecular detection. Positive samples were further examined for the presence of the CDT gene and its three subunits (cdtA, cdtB, cdtC) using a polymerase chain reaction (PCR) approach. Results—To date the cdtB gene was detected in C. jejuni and C. coli isolates from animals at a rate of 70 and 89%, respectively. The cdtC gene was detected in 72% of the C. jejuni animal samples examined to date. Only cdtB was detected in Salmonella spp. and E. coli spp. isolates from animals and at a much lower rate. Both cdtB and cdtC were detected at a higher rate among C. jejuni and C. coli recovered from human cases enrolled in this study (Figure 1). Conclusions—The high prevalence of the CDT genes among Campylobacter isolates in both animal samples and human clinical cases suggests a possible critical role for the toxin in the pathogenesis of the diseases caused by these pathogens. By virtue of its toxicity, CDT has been incriminated in the risk of chronic gastroenteritis sequelae, including Inflammatory Bowel Disease and is likely to play role in the risk of this disease among human population in Qatar.
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Towards A Wearable And Wban-Based Health Monitoring And Automatic Diagnosis System For Low-Cost Personal Healthcare In Qatar
المؤلفون: Eng Hock TayPopulation aging is a worldwide phenomenon, but its impact on Qatar is unique. It is reported that Qatar's elderly population is estimated to reach 21% by 2050 and studies have shown that aging has the strongest impact on long-term care expenditures. Moreover, cardiovascular disease is the leading cause of death in Qatar and the mortality rate is ever-increasing. Qatar now has a public health service providing free or very low cost health care for its nationals. However, due to a dramatic rise in the number of people with illnesses and high costs associated with managing and treating them, Qatar government might face financial burden of such medical support. Therefore, a comprehensive solution has been developed to deliver innovative, low-cost and qualitative health services to Qatar. The proposed system is low cost and compact with self-monitoring and automatic diagnosis function, which encourages the participation of the whole nation for the prevention of illnesses or early prediction of diseases such that pre-emptive treatment can be delivered. The underlying idea is that prevention is better than cure, and when cure is required, it is to start as soon as possible, preferably before any symptoms become apparent. This implies less time and less treatment before the illness becomes complex and out of control, thus saving resources. In this project, a wearable sensor platform has been developed for long-term and continuous ECG and Photoplethysmograph (PPG) measurement (Fig.1). The design of the platform meets the requirement of comfortable, durable and washable. A novel sensor node with single highly-integrated board had been designed (Fig.2), which comprises of a MCU, ECG analog front-end, LED driver circuits, a wireless chip and a FTDI chip. A miniaturized wireless gateway (Fig.3) was also designed and fabricated to wirelessly receive the data from physiological sensor node through wireless chip and relay the data to PC through USB port. For ECG measurement, a novel micromachined electrode (Fig. 4) was designed and the unique characteristic feature of this electrode is that the microneedle array is made of heavily doped silicon, which is electrically conductive and eliminates the requirement to dope Ag/AgCl or metal layer on the microneedles for electric contact. The microneedle array is fabricated at wafer level using three step deep reactive ion etching (RIE) process. A watch-like gadget had been further developed as an enhanced gateway to replace the PC for data acquisition and real-time plotting, which comprises of NXP LPC2148, Nokia LCD screen, SD card and wireless chip as shown in Fig. 5-6. All measured signals from own-customized sensor nodes will be wirelessly transmitted to this gateway and then be real-time saved on SD card or plotted on the LCD screen. Recently, a miniaturized Bluetooth-based three leads ECG sensor chip (Fig. 7) was developed and fabricated to provide more ECG information for further classification and sentinel events detection. A WAP-based telemedicine system has also been developed and its aim is to facilitate the user to utilize WAP devices (e.g., iPhone) as mobile access terminals for general inquiry and monitoring services (Fig.8).
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A retrospective study examining climatic influence on the respiratory health of Qatar residents
المؤلفون: kim critchleyThere are obvious and well known links between air quality and acute respiratory illnesses that are common in Qatar and other Middle Eastern countries. For example, recent studies have documented a number of respiratory problems associated with inhalation of dust during dry, windy periods. In Qatar, exposure to dust and sand are anecdotally associated with a variety of respiratory issues including asthma and chronic obstructive pulmonary disease (COPD). These illnesses may be brought about by physical damage caused by the particles themselves, or by microorganisms that can be associated with these particles. In this study we will examine the relationship between different climatic variables, daily airborne particulate matter, and hospital admissions for respiratory problems over an eight month period to establish possible relationships. The results of the study will shed light on the importance of weather phenomena, particularly windy conditions, in impacting respiratory health in Qatar. These data are particularly important as respiratory problems are expected to increase as climate change results in hotter, drier conditions over the next few decades.
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Lipid biomarkers in the identification of halal/haram products
المؤلفون: Aishah LatiffPlant oils, marine and animal fats are major components of the human diet and they are economically important for many exporting countries. Triacylglycerols (TAG) are the major fat components in human diet. Food consumed by Muslims must be HALAL. Food products with a HALAL designation do not only relate to meat, but also include canned, processed and frozen foods, organic foods, bakery products, pastry and beverages, because of the potential use of animal derived (including porcine) products. Two main objectives of this study are; to differentiate lipid profiles in lard, marine and plant oils and to detect lard contamination in food and commercial cooking oils. This method achieved comprehensive TAGs characterization and differentiation in several oil standards and commercial products. These results were obtained from a single analysis on the Dual-cell Linear Ion Trap Mass Spectrometer using protocols which employs full scan MS, wide band activation with MS2, data-dependent CID (collision induces dissociation) with MS3, all from a single injection. The fatty acid composition of each TAG is easily assigned from the loss of specific neutral fatty acids either in MS (APCI mode) or from similar losses in the CID MS/MS spectra. Therefore, this method could be used as a rapid screening method for TAG profiles. A number of unique TAGs were found in animal and plant oils and three unique TAGs were found in lard oil;these TAGs may be employed in lard detection or adulteration in foods or oil as illustrated in this study. Such an approach may be useful in the determination of halal or haram food products. Finally, preliminary work is also presented regarding the utility of phospholipids contained in plant, marine, and animal fats as additional unique markers for the presence of specific individual oils; especially those from porcine products.
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The epidemiology of hepatitis C virus in Qatar: A systematic review and meta-analysis
المؤلفون: Yousra MohamoudAbstract (342 words) Background: The scale and nature of hepatitis C virus (HCV) disease burden in Qatar is poorly known. In addition to establishing the level of infection among the Qatari population, characterizing HCV disease burden is of particular relevance as Qatar has a large expatriate population some of whom are from countries with substantial HCV prevalence. Objective: To investigate the epidemiology of HCV in Qatar among Qataris and expatriate resident populations. Methods: We conducted a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Sources of data included PubMed and Embase databases. Our analysis included all primary studies reporting HCV prevalence or incidence measures in Qatar. Extracted measures were then classified and analyzed on the basis of the study population's risk of acquiring HCV. Meta-analyses were conducted incorporating inverse variance weighting and using a random-effects model to pool summary estimates of HCV prevalence, among general population groups, for Qataris and the population as a whole. Results: We identified seven studies providing a total of 23 measures on HCV prevalence and none on incidence in Qatar. HCV prevalence in the general population was 0.51% (95% confidence interval (CI): 0.43-0.59) among Qataris, and 1.01% (95% CI: 0.43-1.82) overall. Among blood donors the prevalence ranged from 0.3-11.2% depending on country of origin. The highest prevalence was reported among Egyptian migrants followed, though by a large margin, by Pakistani migrants. Among high risk populations, HCV prevalence was as high as 44.6% in hemodialysis patients, 25.8% among cirrhosis patients, and 9.0% among lichen planus patients. Conclusions: National-level HCV prevalence in Qatar is comparable to that in developed countries, but higher prevalence is found in specific expatriate populations reflecting the higher prevalence in the countries of origin. The high prevalence found among high risk groups possibly dates back to exposures that occurred prior to the enforcement of stringent infection control and blood screening protocols, implemented in the 1990s after the virus discovery. Since HCV prevalence is rather low, HCV prevention policy in Qatar should focus mainly on prevention and infection control in clinical settings.
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Lead impairs synaptic transmission by interfering with calcium
المؤلفون: Dietrich BusselbergBackground: Lead (Pb2+) is ubiquitously distributed in the environment and shows significant health effects in humans. In 1999 the WHO published a preliminary study on lead poisoning in the State of Qatar based on a survey conducted during 1995-96. Water, Food and Blood samples were collected. 19% of the 200 blood samples collected exceeded a critical lead content of 10ug/dl, while the highest level was reported in the youngest age group. 47 out of 450 water samples collected were above the WHO guideline level of 0.01mg/l. Of the 204 samples investigating processed food only 4 exceeded the limit. This study underlines that lead poisoning is a silent epidemic and a serious public health concern. Lead toxicity leads to impaired hematopoietic, nervous- and renal-system function. This study summarizes lead neurotoxicity and highlights how lead partially mimics the function of Ca2+ and therefore how it modifies synaptic transmission pre- and post-synaptically. As calcium (Ca2+) is an important signaling ion in many biochemical pathways, lead (Pb2+) has a high affinity to its binding sites and replaces calcium, resulting in a decrease calcium conductance, altered calcium-dependent signaling pathways, vesicular mobilization and vesicular formation. This presentation highlights the major-interactions of lead with the different targets sites on pre and postsynaptic terminal of the neuron. Methods: To understand the basic mechanism of lead toxicity a vast body of literature was screened and analyzed to summarize and understand the complex and multifactorial interactions of lead. The results were divided into two sections: pre-synaptic targets and the post- synaptic effects. Results: Lead targets multiple sites pre-synaptically like voltage-gated Ca2+-channels, Ca2+-ATPases, PKC, Calmodulin, signal cascades like the PLC system. Figures in the pre synaptic sections represent how the release of neurotransmitter is reduced by lead; beginning with the impairment of voltage-gated Ca2+-channel, lead interferes with calcium Ca2+-ATPase followed by the intracellular calcium de-regulation and lead inhibits the fusion of synaptic vesicle with the membrane and therefore the release of neuro-transmitter. Post-synaptic effects of lead result in the generation of the post-synaptic potential and synaptic-plasticity. This section is subdivided in four categories: synaptic transmission, effects on NMDA, long term effects and effects on long term potentiation. As (pre-synaptically) lead reduces the release of neuro-transmitter, post-synaptically the membrane depolarization will be smaller decreasing the likelihood that action potentials will be generated. Overall, lead reduces the chance of a successful generation of (post-synaptic) actions potentials and prevents to initiate processes which are crucial for learning and memory processes. Conclusion Lead mimics the action of the second messenger Ca2+, thereby disturbs the normal physiological function of Ca2+. This review helps to understand the basic mechanism underlying lead neurotoxicity and emphasize the importance of reducing lead contamination. A detailed review (with animated illustrations of pre- and post-synaptic effects of lead) has been recently published by Florea et al., in the Journal of Local and Global Health Science (2013:4).
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New insights into the genetics of DCM from the QCRC intercontinental genetic consortium (QCRC-IGC)
المؤلفون: Despina SanoudouDilated Cardiomyopathy (DCM) is a leading cause for heart failure characterized by an enlarged ventricular cavity causing systolic dysfunction. Although a multifactorial disease, DCM has been attributed to gene mutations in approximately 30-50% of cases. However, the full spectrum of the genetic basis of DCM remains elusive. QCRC-IGC is a Doha-centered intercontinental consortium comprising teams from Egypt, Greece, UK, Italy and the USA. It aims at discovering novel gene variants implicated in DCM pathogenesis and/or progression, through the establishment of a multinational DCM patient cohort and the genetic investigation of over 170 genes (including all DCM genes) using the cutting-edge technology of Next Generation Sequencing (NGS). Herein we present the genetic screening of sixteen DCM patients (5 sporadic and 11 familial), as confirmed by echocardiography and/or MRI, who did not have a history of alcoholism or coronary angiography findings. Over 1,600 variants were detected in each patient, the vast majority of which represent well documented benign polymorphisms. Forty variants had never been reported before, involving the genes: TTN, SYNE1, MYH6, ALMS1, SDHA, MYPN, LAMA2, TPM1, PLEC, FOXD4, ILK, SGCB and DSP. TTN mutations are being detected in 27% of DCM cases. Of particular interest is the polymorphism observed in the gene DSP, as it was detected in two affected sisters of the same family, it represents the only common potentially pathogenic variant shared between them, and it is bioinformatically predicted to lead to a dysfunctional protein product. Importantly, other mutations in DSP have been previously associated with DCM as well as ARVC. Significant findings of immediate research and ultimately diagnostic/prognostic value are beginning to emerge. Additionally, the discovery of novel pathogenic mutations would unveil promising new therapeutic targets. QCRC is currently intensifying the patient recruitment process at the clinical level, while focusing on the molecular characterization of the emerging novel variants using in silico modeling, induced pluripotent stem cells, and systems biology approaches.
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Oral formulations of metformin in semi-solid matrices using solvent evaporation method: Characterization and in vitro dissolution testing
المؤلفون: Husam YounesPurpose. To formulate and evaluate sustained-release hard gelatin capsules (HGC) filled with Metformin hydrochloride (MH) dispersed in semisolid matrices able to increase MH bioavailability and address the shortcomings in the currently marketed sustained-release tablets. Methods. Gelucire® 50/13 and various proportions of high molecular weight hydrophilic polymers, hydrophobic oily semisolid excipients, and muco-adhesive polymeric materials were dissolved in dichloromethane (DCM). MH powder previously micronized (250 micron) was suspended in the excipients' prepared solution. DCM was evaporated in the fume hood for 12 hours at room temperature followed by four hours of evaporation under vacuum at 40°C using vacuum oven. The prepared MH loaded matrices were filled in HGC each containing 500 mg MH and were subsequently characterized using Differential Scanning Calorimetry (DSC) and X-Ray Diffraction Analysis (XRD). The prepared HGC were subjected to content uniformity and in vitro dissolution testing according to the USP-35 compendial requirements. The dissolution data were compared to instant and sustained-release marketed tablets. Results. MH content in HGC ranged from 98 to 101%. All the prepared semisolid filled HGC resulted in extended-release profiles of MH that lasted between 3 to 7 hours and demonstrated a release pattern which typically follows the release from mixes of triglycerides with polyethylene glycol esters of fatty acids. The incorporation of muco-adhesive excipients like Carbomer to the Gelucire® 50/13-MH semisolid matrices extended the release of MH from 3 hours initially to 7 hours due to the formation of a gel layer around the matrix. However, the incorporation of excipients like PEG35000 and Gelucire® 44/14 along with the muco-adhesive excipients sustained the release of MH up to 9 hours. XRD analysis of the MH prepared matrices demonstrated minor changes in the crystalline nature of MH. Depending on the loading ratios and the nature of the semisolid matrices used, DSC analysis revealed the changes in MH crystallinity to be from 100 to 17%. Conclusion. HGC formulated using semisolid matrices showed promising results in extending the release of MH. However, bioavailability studies to test the ability of such Gelucire based HGC of MH to improve its bioavailability and in vivo residence times are future plans. Acknowledgements: This work was made possible by a NPRP award [NPRP 09-795-3-215] 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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Preliminary studies for thalamic visual prosthesis to treat blindness resulting from glaucoma: A deep brain stimulation approach
المؤلفون: Siva Mahesh TangutooruAbstract- Developing visual prosthesis in human cortex or on retina has gained some importance over years. However, visual prosthesis in thalamic region targeting lateral geniculate nucleus (LGN) has few advantages though. This paper proposes a simulation model for deep brain visual prosthesis that will harness the capacity of the residual central visual neurons. This prosthesis creates percepts, substituting an engineered prosthetic for the image capture and early visual processing properties of the LGN neurons that we plan to drive artificially. Introduction- Glaucoma is an incurable neurodegenerative disorder leading to permanent blindness. Glaucoma accounts for blindness in 4-5 million of the world's people and is unusually prevalent in Eastern Arabia. In Qatar, glaucoma is said to account for 40% of its cases of blindness and 16% of people above age 40 are affected by this disease. Restoration of visual function in glaucoma by stem cell therapy or genetic engineering could provide a quite good solution, but the likelihood of these approaches providing a cure for glaucoma in the near term is tenuous. A neuroprosthetic approach offers the most likely short-term treatment for glaucoma-induced blindness. This paper describes early progress made towards designing a visual prosthesis to treat blindness through glaucoma. In glaucoma, there is evidence that the LGN undergoes degenerative changes in human patients [1]. Obviously, LGN degeneration during glaucoma needs to be factored into the design of the electrode array. Design and Concept- The proposed design of the visual prosthetic requires many components (Fig 1). The electrodes are positioned in the dorsal layers of the LGN and all other components located outside the body. Images are captured and adjusted for position of gaze and processed by spatiotemporal filters to provide signals that can be used to drive LGN neurons similar to their natural drive. These signals drive the electrode array with a pattern of stimulation pulses. Electrical stimulation circuitry provides charge-balanced current pulses to the electrodes to activate LGN neurons. Results- An array of electrodes distributed across a semi-elliptical shaped flat surface that interfaces with the top three LGN layers (layers 6-4) is designed. The flat semi-elliptical shaped head, resembling the tip of a knife, facilitates easy penetration through the soft brain tissue. To match LGN dimensions, the head would be 2.5 mm wide, 2 mm deep and 50 µm thick. Fig 2 shows the proposed design with 184 hemispherical shape electrodes placed on either side of the lead with diameters of 50 µm and center to center spacing of 200 µm. The hemispherical shape of electrodes avoids concentration of current density at one place since it does not have any corners or edges. Thus these electrodes deliver uniform current density around the electrode minimizing the electrode and tissue damage. The electrodes are placed in a triangular array to maximize packing density and maintain equal distance between neighboring electrodes. Reference- [1] Gupta, N. et al., 2009. Atrophy of the lateral geniculate nucleus in human glaucoma detected by magnetic resonance imaging. The British journal of ophthalmology, 93(1), pp.56-60.
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Analyzing the health burden from road trauma in Qatar: Which indicators are best?
المؤلفون: Rafael ConsunjiThe adverse health outcomes, road traffic injuries [RTI's] and deaths, that result from motor vehcile crashes [MVC's] in Qatar have been measured and evaluated. Improvements in this field have been noted; citing improvements in numerous ways using a variety of tools. Deaths are most commonly used with measures of non-fatal outcomes of MVC's rare. The number of MVC's causing injury, number of traffic violations and citations issued and MVC rates per 10,000 vehicles have been applied. The use of the size of the general population as a measure fo RTI exposure or risk is common. Incorporating the highly diverse and changing character of Qatar's population and the even higher differences in road risk exposure between sub-populations must be done. Furhermore, analyses of the differential risk for each of the different RTI mechanisms experienced by the different road users [i.e. rollover vs pedestrian-vehicle collision or driver vs passenger vs pedestrian] must be performed. All of the parameters have been reviewed and analyzed. The tools and parameters best suited to evaluating the health burden from RTI's in Qatar will be presented.
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Design Of A New Wavelet-Based Preprocessing Stage For Improved Time-Frequency Detection Of Fetal Movements
المؤلفون: Taoufik Ben JabeurDesign of a new Wavelet-based preprocessing stage for improved time-frequency detection of fetal movements Dr. Taoufik Ben Jabeur and Pr. Boualem Boashash Department of Electrical Engineering, Qatar University Background: Improving Newborn Health Outcomes can be achieved by monitoring Fetal Movement (FetMov) activity which relates directly to the fetus well-being. Several methods exist to record these Fetal movement (FetMov) signals including active (Ultrasounds) and passive ways (accelerometer). Ultrasound is an accurate measurement but expensive and intrusive; for these reasons, capturing FetMov through accelerometer sensors is a preferred option as it is low cost and nonintrusive. In this approach, different sensors are placed on the abdomen of the pregnant woman. Each sensor produces a FetMov signal. The recorded FetMov signals have been shown to be noisy and non-stationary signals containing several artifacts. Thus, a pre-processing stage is required to reduce the noise and eliminate the artifacts. Objectives: This work aims at designing a new pre-processing stage for improving FetMov detection by applying Wavelet de-noising algorithm followed by a threshold given by Kurtosis parameter. Methods: The new method is based on a Wavelet de-noising algorithm followed by a high pass filter to reduce some artifacts. A threshold given by Kurtosis parameter is used in the elimination of the artifacts. Results and conclusion: Simulation results show that the proposed pre-processing stage allows to reduce the noise and to eliminate more than 70% of the artifacts. Few artifacts are still present in the FetMov signals. As the FetMov signal is non-stationary, we use a Time Frequency Matched filter detector (TFMF) based on QTFDs to detect FetMov from these artifacts. The proposed preprocessing stage combined with TFMF detector improves significantly the performance of the detection of the FetMov signal leading to possible improvements in health outcomes for the fetus. Keywords: Fetal movement; Wavelet; Time frequency Matched Filter; Quadratic Time Frequency Distribution.
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