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
1 - 20 of 541 نتائج
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A mutation at the H2B histone family [H2BFWT] gene causes a novel X-linked mental retardation with abnormal head shape syndrome
المؤلفون: Vasiliki Chini, Rehab Ali, Namat Khattab, Tawfeq Bin Omran, Yasser Al-Sarraj, Marios Kambouris and Hatem El-ShantiA non-consanguineous Arabic family affected by a putative novel seemingly X-linked disease characterized by mental retardation and abnormal head shape was studied by gene mapping, candidate gene mutation screening and whole X chromosome Exome sequencing of a single affected member to identify the responsible gene defect. Clinical presentation includes mental retardation, hyperactivity, hypotonia, turricephaly (in one affected), dolichocephaly (in the other affected), narrow face, downward slanted palberal fissures, large ears, open mouth appearance, long and slender fingers. Neurologic and metabolic evaluations including urine organic acid, lysosomal enzyme analysis, gaunidinocompound, CDG and Fragile-X syndrome were negative. SNP genotyping with the HumanOmniExpress bead chip [Illumina, USA], analyzed with the GeneMapper software mapped the responsible gene to four possible X-chromosome intervals [p22.33-22.2, p22.2-21.1, p31.1-q22.3, q26.3-28] as the family structure did not allow identification of a single interval with a significant LOD score. Based on the clinical presentation one candidate gene (FGF16) was screened but no pathogenic mutations were identified. Whole Exome target enrichment Next Generation Sequencing for the X chromosome was performed on the ABI SOLiD4 platform for a single affected individual. Three variants were identified within the linkage intervals: AMMECR1 [c.C208T/p.L70F] was excluded as it did not co-segregate with the disease phenotype. A second variant (c.C11T/p.P4L) in the Rab40 GTP-binding protein gene (RAB40AL). Pathogenic mutations within this gene have been associated with Martin-Probst X-linked mental retardation syndrome (MRXSMP) which presents with a different phenotype characterized by hearing loss. The last variant (c.G227A/p.C76Y) at the H2BFWT histone family gene has damaging effects according to PolyPhen and SIFT protein-modeling software, co-segregates to the disease phenotype and is absent in 752 ethnically matched control chromosomes. No known diseases have been associated with mutations in H2BFWT apart from male infertility. Tissue specific H2BFWT expression studies show expression in human fetal brain, making this mutation the likely developmental defect. At present, mutation analyses in additional healthy normal maternal male relatives are underway for the possible exclusion of H2BFWT as the offending gene.
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On articulation and phonological disorders among Arab children
المؤلفون: Yousif Ali El-ImamOne important type of speech sound disorders is articulation and phonological disorders that affect children of age between 2-8 years. All normally developing children follow a unique developmental timetable, table 1 in which they acquire articulation and phonological skills to correctly pronounce both consonants and vowels to make the sound patterns of their respective language. Previous statistics, table 2 show that the number of Arab children, in the age group 2-8 years, who suffer from articulation and phonological disorders, is significant. To be able to test, assess, and evaluate the effect of therapy on these disorders, there is need to conduct research and development that would culminate in the availability of speedy, versatile and interesting computerized tools for use by Speech and Language Therapist, SLPs in standardized test, assessment, and evaluation of articulation and phonology disorders among the children, figure 1. There are prerequisites to the development of these tools such as the development of a suitable phonetic and phonological vocabulary (see table 3) of Modern Standard Arabic, MSA that is spoken by such children and which will meet the test and assessment requirements for speech disorders. The vocabulary could then be used to create a speech corpus for children with normal speech who are in the same age group as the children with disordered speech. Such speech corpus could then be used as a frame of reference to set the standards and norms for children speech. The standards and norms can be used by SLPs to compare normal children against children suspected of having the disorder. The speech corpus could also be used by researchers to develop limited vocabulary, speaker-independent phonetic speech recognizers that would help SLPs during speech therapy and evaluation. To meet the ultimate goal of finally producing efficient and versatile computerized tools to assist SLPs in their mundane tasks of handling articulation and phonological deficits among children in an efficient manner, we envisage a project with the following objectives in mind: 1) develop a comprehensive articulation and phonology vocabulary that represent all the sounds of MSA spoken by the children in all their important articulation and phonological contexts, and 2) use the vocabulary to create a norm speech corpus that represent the articulation of all sounds for children with healthy speech production. The corpus should include significant quantities of speaker-dependent data for a significant number of children with normal speech and would be segmented, labeled and transcribed according to the standards used for such tasks. The development of test and assessment vocabulary and the creation of the speech corpus from such vocabulary are the prerequisites for any investigation on articulation and phonology disorders. Firstly they would help the research community to study the disorders and secondly, after the development of suitable computerized tools, they assist the SLPs to test, assess, and evaluate the effect of treatment for articulation and phonological disorders among children. In this article, we present the status of the research and outline a roadmap to achieve our objectives and ultimate goal.
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Dynamic trends in intestinal parasitic infections among recently arrived immigrant workers, settled immigrants and long-term residents in Qatar
المؤلفون: Jerzy BehnkeThe expanding economy of Qatar in the last two decades has attracted immigrants, often from countries with poor socio-economic standards. Many arrive with patent intestinal parasitic infections, and recent analyses have indicated consistently rising trends in the prevalence of some infections. We have used several approaches for quantifying the prevalence of parasitic infections brought into the country by immigrant workers. Using data from 2009 we compared prevalence of infection in newly arrived immigrants with that in long-term residents from the same nations (matching countries among which both newly arrived immigrants and long-term residents were represented) and found that intestinal parasitic infections fell from 26.5% among the newly arrived workers to 16.5% among residents, the biggest drop being among helminth infections (from 20% to 9.2%). Helminth infections among newly arrived workers varied significantly by region of origin, and hookworm infections in particular were frequent among the Nepalese (18.9%) but in contrast to all other regions, did not fall markedly after acquisition of residency status (17.5%). Protozoan infections changed little overall, because some species increased while others declined: there was a significant increase in the prevalence of Blastocystis hominis among residents compared with immigrants and a concomitant declined in both Giardia duodenalis and Entamoebae histolytica/dispar. More recently we analyzed another data-set of 18,563 hospital records of subjects from 57 countries who in the period from 2005 to 2011 sought medical assistance for a variety of ailments, to enable trends to be identified across a seven year period. We found that overall 8.6% were infected with one or more species of parasite, but in contrast to the earlier years, in the last three years there were falling trends of prevalence (from 13.4% in 2009 to 4.9% in 2011) providing some optimism that parasitic infections among the resident immigrants have begun to decline. We identified also geographic regions from which resident workers still maintain relatively high prevalences of helminth infections despite their long-term residence in Qatar. Workers from Nepal were the most likely to carry hookworm infections (19.7%) followed by other W. Asian nationals including in descending order those from Bangladesh (8.3%), Sri Lanka (6.8%) and India (4.4%). Helminth infections are probably acquired abroad during visits to their home villages, whilst protozoan infections are reinforced by transmission in Qatar, possibly in the poorer areas of the state where immigrant workers live. Our results have clearly identified high risk groups among the many foreign immigrant workers and have clear implications for the health authorities. The two outstanding problems that now require further attention are the still relatively high prevalence rates with hookworms among the Nepalese and other Asian workers and the rising trend in the prevalence of B. hominis with host age among both Qataris and foreign residents. Our attention is currently focused on unravelling the reasons for the relatively high prevalence of hookworm infections among resident Asians, and especially the Nepalese, in the hope that eventually the decline in these infections can be accelerated even more markedly than has been observed in recent years.
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Targeting alterations in the endocannabinoid system of rodents and non-human primates for the study of autism
المؤلفون: Renato Malcher-LopesAutism spectrum disorders (ASD) are a group of neuro-developmental disabilities, which, in many cases, is characterized by severe impairments in communication skills, social interaction, psychomotor coordination, behavioral control and emotional stability often accompanied by deficits in cognition, attention and sensory processing. According to a recent study conducted by Dr. Fouad Alshaban (Shafallah Medical Genetics Center, Doha, Qatar), the accurate prevalence rate of autism-spectrum disorders in Qatar is still uncertain. However, there is a general concern that it might be increasing in the last few years. The symptoms of ASDs are typically present before age 3 years, but frequently a formal diagnosis take longer to be established, which may compromises the efficacy of developmental and life-quality improving strategies. In most countries of the world the scenario is not much different. It has been shown that autism-associated neuroligin-3 mutations disrupt tonic endocannabinoid signaling in animals. Endocaanabinoids are neuromodulators produced by the brain, which act upon the same receptors and neuronal circuits affected by exogenous cannabinoids from the plant Cannabis sativa. This system is central for brain homeostatic activity control, learning, social interaction, memory formation and emotional modulation, among several neuronal and physiological functions. Here we present our proposal to use primates and valproate-treated rodents (an animal model for autism) in order to deepen our knowledge about the involvement of defects in endocannabinoid system as etiological factors capable of generating behavioral and cognitive aspects related to human autism. The reasoning behind the use of two species is to facilitate the conceptual bridge between the findings obtained in valproate-treated rodents and the understanding of the importance of the endocannabinoid system for social interaction and emotional behavior in primates. At first, this combination has the potential to point out possible pharmacological treatments based on modulation of the endocannabinoid system and in the identification of biomarkers in rodents. Secondly, this knowledge can help to develop, and to ethically justify, the creation of primate models for the study of pharmacologically treatable aspects related to human behavior that cannot be studied in rodents. In Brazil we have the privilege to work with non-human primates in a high-standard, naturalistic facility, the Primatology Center of the University of Brasilia (in the capital of Brazil). Therefore, we are taking advantage of this capability to test new hypotheses relating endocannabinoid signaling defects with autism symptoms and eventually generate a non-human primate animal model that, in one hand, may help on the discovery of molecular markers for early diagnosis and, on the other hand, may help the development of pharmacological tools to treat important symptoms of ASD. We want to share and discuss our ongoing project in this meeting as part of an effort to foster found raising and potential collaborations between our group and research groups from Qatar.
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Correlation between quality of life and disease severity in children with atopic dermatitis in the State of Qatar
المؤلفون: Hessa Al Bouainain and Mohamed Ibrahim AllamCorrelation between quality of life and disease severity in children with atopic dermatitis in the state of Qatar Background: Atopic dermatitis (AD) is an itchy, chronic or chronically relapsing, inflammatory skin condition which is most prevalent in childhood. It is known to affect 10-20% of children. The prevalence of AD has increased during the past 3 decades and is probably due to modification of lifestyles and environment. Atopic dermatitis (AD) can affect the behavior, life and development of children. Little is known regarding the effect of AD on the quality of life (QoL) in children of the Gulf region and especially in the state of Qatar. Objectives: To study the impact of AD on the QoL in children and its relation to disease severity in the state of Qatar. Methods: This study was conducted on 45 patients with atopic dermatitis aged from 5 to 16 years who attended the outpatient clinic of the Dermatology Department, Rummilah and Al Khor Hospitals, Hamad Medical Corporation, Doha, Qatar. The UK diagnostic criteria of AD were used for the diagnosis of atopic dermatitis. Disease severity was assessed using modified SCORAD (SCORing Atopic Dermatitis) measuring only objective criteria .The Children Dermatology Life Quality Index (CDLQI) was used to quantify the impact of AD on children's quality of life. SPSS 14.0 statistical package has been used for the analysis. Correlation coefficient (Pearson) was calculated to see associations between variables. Results: There were a positive significant correlation between objective SCORAD and each question from 1 to 10 as well as the total score of CDLQI except for question 2, the strongest relation between objective SCORAD and CDLQI was found in question 1 (symptoms) and question 9 (sleep). It was statistically evident that as the SCORAD index increases the CDLQI increases. Conclusion: The study has shown adverse effects of AD on children QoL especially on symptoms and feelings and a positive correlation between CDLQI and modified SCORAD which denote the effect of AD on the lives and development of children. We recommend the use of CDLQI in research work as an additional subjective measure to the clinical objective scoring tools used in chronic skin diseases. Health economists and caregivers should put the impact of skin diseases (non-life threatening diseases) on the QoL of patients, especially children and its implications for psychology, development, social functioning and school outcome.
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Novel biomaterial for bone grafting and healing synthesized from bovine serum albumin using sub-critical water technology
المؤلفون: Wael Abdelmoez and Hiroki YoshidaThe interest in bone and softtissue replacement achieves rapid advances throughout the last decades. Injured bone has a unique ability to regenerate which leads to complete anatomic and physiologic repair. However, not every bony defect can beself-repaired. Repair of large osseous defects caused by neoplasms, cysts, trauma, infection, congenital diseases and surgical intervention are major problems in oral and maxillofacial field. The current approach is to use bone and bone substitutes for filling such defects. The aims of filling such osseous defects are to preserve the morphologic contour, restoration of the mechanical strength and function, elimination of the dead space to reduce postoperative infection, and the prevention of ingrowths of soft tissue. When conditions are favorable for regeneration of bone, such goals can be achieved without the need for grafting techniques. However, in many large lesions or in the absence of favorable conditions in small defects, the morphological contour is not completely restored and the bone remains weak. Different grafting materials have been introduced into the field in the last decade. The profound limitations of biological grafts have prompted the use of synthetic materials as an alternative to autogenous and allogenic bone grafts.In the present invention, we succeeded in manufacturing of a novel biomaterial in the field of bone healing. Our novel biomaterial synthesized from bovine serumalbumin using our newly developed technology (sub-critical water technology). The biomaterial showed a variety of mechanical properties and biodegradability that allowed for its application in the biomedical field and in particular as an alloplastic bone substitute. In our way to validate the applicability of our novel biomaterial, we co-operated with the department of Oral and Maxillofacial Surgery Faculty of Dentistry, Al Minia University, to evaluate our material as an alloplastic bone substitute through animal test. The results revealed satisfactory results when used as a bone grafting material in surgically created bone defects in the rabbit models. The obtained results showed that these novel materials have the following properties: Biocompatibility, Nontoxic and nonirritant, Act as a haemostatic agent and maintained the blood clot inside the defect, Osteoconductive property, Biodegradability property,easily manipulated and handled.The most important findings from the obtained results revealed that these novel materials have the ability to accelerate bone healing specially at the early stages following implementation of the material. Part of the work was patented in Japan with patent number 2005-028066 and published in high impact factor scientific journals worldwide 1, 2,3, 4, 5 . In the presnt work the most new obtained data concerning biocompatibility and animal test will be presented
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Human hexokinase 2: A key enzyme and promoter of tumor growth
المؤلفون: Hussain Mir Nawaz and Wael RabehMalignant tumors metabolize glucose through glycolysis to lactic acid and produce ATP at an accelerated rate when compared to normal cells, a phenotype detected clinically using Positron Emission Tomography (PET). Out of the four available isoforms, Hexokinase 2 (HK2) is the major expressing isoform in cancers specially those that metastasize and kill their human host. In malignant cells, HK2 not only improves the cell's energy supply but also protects cancer cells against apoptosis through direct interaction with the mitochondria and Voltage Dependent Anion Channel 1 (VDAC1). Here we report the 3D crystal structure of the human HK2 in complex with glucose and glucose-6-phosphate, the first enzyme in the glycolytic pathway. The N- and C-terminal domains are catalytically active and linked by a long seven turn a-helix. Each domain contains an active site that is sandwiched between a small and large sub-domain. Cancer patients with high HK2 gene expression level showed a worse prognosis and aggressive character. Therefore, HK2 is an ideal therapeutic target to inhibit cancer proliferation and tumor destruction. Very limited literature describes HK2 and detailed understanding of the HK2 structure and function is needed to characterize its mechanism, to understand its role in cancer metabolism and to develop new drug treatments to slow the rate of cancer proliferation.
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Computational MR imaging in tumors: Fiber tractography for tumor detection and its fundamental challenges
المؤلفون: Andrew Kiruluta, Alexey Tonyushkin and Qutaibeh KatatbehThe sensitivity of magnetic resonance (MR) to diffusion has long been exploited as a method for investigating molecular motions in complex systems. The recognition that MR can be made sensitive to the details of anisotropic diffusion in structured materials led to the formulation of the problem as a tensor (DTI) rather than a scalar. New directions exploiting MR diffusion imaging techniques can yield essential new information previously not accessible with other imaging modalities as potential cancer biomarkers. We investigated the feasibility of applying DTI for in-vivo fiber tractography of the prostate. We carried out retrospective study of men with biopsy proven prostate cancer. All patients had undergone prostate MRI with an endorectal coil on a 1.5 T MRI scanner. Diffusion weighted images were acquired with a single shot echo-planar acquisition, with six diffusion sensitizing directions. Preliminary fiber track data was generated as in Fig. 1 using Diffusion Toolkit and displayed with TrackVis (trackvis.org). This data was then used to identify multiple hand drawn regions of interest (ROI) over areas of pathologically proven tumor, the central gland and the normal peripheral zone of the gland. For quantitative analysis, we introduced a track density parameter, which is the number of tracks in a given ROI divided by its volume, as a normalized measure of the tracks passing through the ROI. The values were statistically analyzed and correlated with the staging. One of the key goals of the study is to apply this method to analyze post radiation treatment cases where other modalities fail to yield contrast necessary to distinguish cancerous tissue from necrosis. The main challenge of fiber tractography, however, is the existence of multiple-fiber orientations within an imaging voxel which renders the diffusion tensor model inadequate. The practical limitations imposed by the requirement for a wide spectral sampling of the diffusion spectrum in q-space, can be met if these impulse diffusion gradients are replaced with chirped oscillatory gradients. In this abstract, asymmetrical chirped diffusion sensitizing gradients are shown to yield an efficient sampling of q space in a manner that asymptotically approaches the spectral coverage afforded by delta function diffusion sensitizing gradients. The asymmetrical nature of the gradients is an extension of the method recently proposed by Laun et al.[1] that allows the diffusion experiment to preserve the phase information and hence reconstruct the exact shape of the underlying structural restrictions -see Fig. 2. The challenge is the consequent reduction in diffusion sensitivity as one probes higher frequency dynamics. This problem is addressed by restricting the gradient power to a spectral bandwidth corresponding to the diffusion spectral range of the underlying restrictive geometry. Simultaneous imaging of diffusion at microscopic resolution and at temporally resolvable diffusion time-scales thus becomes possible in-vivo. Fig. 2: Inverse imaging of a triangular restriction using asymmetrical diffusion encoding gradients [1] F. B. Laun, T. A. Kuder, W. Semmler and B. Stieltjes, Phys. Rev. Lett. 107, 048012 (2011).
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Food safety priorities in the Middle East
المؤلفون: Walid AlaliThe foodborne and waterborne disease continues to pose significant health problems in the Middle East. This region specifically Arabic speaking countries, imports large amounts of food products from all over the world. At the same time, this region exports a variety of food commodities to many countries worldwide. The increased international food trade, changes in agriculture production, food processing, and consumer demand for wholesome safe food have led to new food safety challenges which have impacted the food safety systems. There are country- and intra-country/subregional specific based food safety systems. The Gulf Cooperation Council (GCC) is an example of a subregional coalition aimed at harmonizing their country-members' food safety standards based on Codex Alimentarius. There are a number of challenges and potential opportunities available for the Middle Eastern countries to enhance their food safety systems. These challenges include: 1) domestic and imported food inspection, 2) laboratory capacity and staff training, 3) foodborne surveillance systems, and 4) scientific research to support policies and regulations. Given these challenges, there are a number of opportunities to enhance food safety in the Middle East. These include: 1) Training of inspectors for domestic and imported food and making available a detailed and comprehensive manual to follow as a guideline in their daily work. This guideline would be a valuable aid especially to those with limited training. In addition, standard uniform methods for sampling and data collection would be needed, 2) building research institutions for food safety and quality research that supports laboratory capacity, surveillance, and data analysis, and 3) better risk assessment and communication is needed to focus on highest foodborne disease risks and to link the strategies to reduce those risks across the full food production chain. Special consideration should be given to certain situations in specific countries to overcome barriers of non-collaboration among disciplines and responsible agencies.
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Identification of de novo and rare inherited mutations in autism spectrum disorder probands from Qatar by whole genome sequencing.
المؤلفون: Hatem El-ShantiAutism spectrum disorder (ASD) is a clinically and etiologically heterogeneous condition with high prevalence amongst all world populations. Due to the life long morbidity, ASD poses a profound world-wide public health challenge. Despite its obviously high heritability, a genetic cause is only identified in a small fraction of patients due to its complex etiologic heterogeneity. Recently, whole genome sequencing (WGS) emerged as a powerful tool for variant discovery due to its comprehensive and uniform coverage and is expected to be beneficial for studying ASD. We used WGS to examine 20 families with ASD, mainly from Qatar, as well as from a few other Arabic countries, to detect de novo or rare inherited genetic variants predicted to be of pathogenic significance. All probands were diagnosed with ASD by at least an ADI-R (Autism Diagnostic Interview-revised) evaluation, in addition to other screening or confirmatory tools and were recruited from the Shafallah Center for Children with Special Needs. Due to the nature of the ascertainment source, all probands had associated intellectual impairment. In all probands known causes of ASD were excluded, fragile X syndrome by PCR and Southern blott, Rett syndrome (for females) by Sanger resequencing and MLPA and Copy Number Variations (CNV) by SNP genotyping on an Illumina 1M-Duo SNP chips. Among all probands, we identified deleterious de novo mutations in six (30%) families and inherited X-linked in two families (10%). We did not identify any inherited autosomal dominant mutations, but identified putative inherited autosomal recessive varations in three families (15%). The deleterious de novo variants were found in five previously unrecognized autosomal genes, and in one known autosomal ASD gene. The inherted X-linked variations were found in ASD risk genes. We are interested in deeper examination of the putative variations with autosomal recessive pattern of inheritance, since the parents of 60% of the probands are consanguineous. The deeper examination will employ the study of knock-out and knock-in mouse models and different in silico and in vitro protein modeling studies. These results so far suggest that WGS of a trio coupled with thorough bioinformatic analyses provide a powerful diagnostic tool in ASD. It is also a potent methodology for gene discovery in ASD, which may provide the basis for genetic testing for early diagnosis and early targeted intervention with a final goal of better outcome.
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Anti-allergic effects by arginase inhibitors: Role of nitric oxide
المؤلفون: Herman Meurs, Ramadan Sopi, Mirjam Simoons, Paul Jackson and Harm MaarsinghAnti-allergic effects by arginase inhibitors: role of nitric oxide Herman Meurs¹, Ramadan Sopi¹´², Mirjam Simoons¹, Paul Jackson³, Harm Maarsingh¹´³ ¹Department of Molecular Pharmacology, Groningen Research Institute for Pharmacy and Groningen Research Institute for Asthma and COPD, University of Groningen, Groningen, The Netherlands, ²Faculty of Medicine, University of Prishtina, Prishtina, Kosovo, ³Department of Pharmaceutical Sciences, Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, FL, USA Using animal models for acute and chronic asthma, we demonstrated that inhaled arginase inhibitors attenuate allergen-induced early and late asthmatic reactions, airway hyperresponsiveness, airway inflammation and airway remodeling. Moreover, it was found that arginase inhibition greatly reduces the sensitivity of the airways to the inhaled allergen, suggesting that arginase inhibitors may have an anti-allergic effect by inhibition of mediator release from mast cells. Since arginase activity regulates nitric oxide (NO) synthesis via competition with NO synthase (NOS) for the common substrate L-arginine, and activation of mast cells is inhibited by NO, we hypothesized that the anti-allergic effect of arginase inhibition involves increased NO synthesis. This hypothesis was investigated in precision-cut lung slices from actively ovalbumin (OVA)-sensitized guinea pigs, by using video-assisted microscopy to measure allergen (OVA)-induced airway constriction. OVA induced a dose-dependent airway constriction with a mean maximal effect (Emax) of 98% and a mean EC50 of 0.039 µg/ml. The arginase inhibitor 2(S)-amino-6-boronohexanoic acid (ABH, 1 µM) significantly reduced the sensitivity towards OVA by >100-fold to 5 µg/ml, whereas the Emax of OVA was reduced to 50%. The effects of ABH were mimicked by the arginase inhibitor N?-hydroxy-nor-L-arginine (nor-NOHA, 5 µM). The NOS inhibitor N?-nitro-L-arginine methyl ester (L-NAME, 100 µM) largely reversed the inhibitory effect of ABH, indicating the involvement of NO. Remarkably, inhibition of arginase and/or NOS did not affect airway constriction towards exogenous histamine, the primary contractile mediator released by mast cells upon allergen challenge. This indicates that ABH reduces the histamine release from mast cells rather than the responsiveness to this mediator. In conclusion, inhibition of arginase greatly reduces airway responsiveness towards allergen by increased NO synthesis, most likely preventing mediator release from mast cells and subsequent airway constriction. Supported by the European Erasmus Mundus partnership JoinEU-SEE
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Severe loss-of-function mutations affect critical genes and pathways in the Qatari population
المؤلفون: Khalid Fakhro, Juan Rodriguez-Flores and Ronald CrystalExome sequencing was used to study genetic variation in the Qatari population. We sequenced 100 healthy Qataris (50X average depth, with >80% of sites at >10x depth) representing the 3 major Qatari genetic subpopulations (Q1 - Bedouin, Q2 - Persian/South Asian, Q3 - African). A total of ~174,000 high quality variants were identified, of which 1306 were predicted to cause loss of function (frameshift/stop-gain/splice/start-loss) in 1102 unique genes. Of these, 471 (36%) were novel Qatari variants (absent from public databases) of which 43 were observed in 2 or more individuals, suggesting a population allele frequency =1%. 54 of 471 loss of function mutations affected genes in the OMIM database with a confirmed disease-causing status. Of these, 30 occurred in genes known to cause severe autosomal recessive disease. Of interest, some of these mutation had allele frequencies of up to 8% in Qataris. We further focused on the subset that were nonsense mutations (n=671/1306). These occurred in 616 of 1102 unique genes and resulted in a median truncated protein length of 54.3%. 237 of 671 nonsense mutations were novel to Qataris, suggesting that a significant number of variants from this population are yet to be sampled and covered in public databases. When nonsense alleles were considered in the 3 separate Qatari subpopulations, the Q3 population displayed the highest number of nonsense alleles per individual (mean: 40.7, range: 28-55), consistent with the highest genome diversity due to African ancestry. Surprisingly, despite having the lowest number of heterozygous nonsense mutations (mean: 22.8, range: 16-31), the Q1 subpopulation had at least 20% more homozygous nonsense mutations (range: 2-15, mean: 6.7) per individual than either Q2 or Q3, consistent with the high levels of consanguinity in this population. Specifically, the Q1 had significantly higher allele frequencies than the rest of the world for 2 autosomal recessive disease genes, including 1 individual homozygous for a nonsense mutation in POMT1 which causes muscular dystrophy, and 4 individuals heterozygous for a mutation that truncates the Holoprocencephaly-causing TGIF1 gene to 7.5% full length. Additionally, the population as a whole had higher allele frequencies for 6 other autosomal-recessive-disease-causing mutations, bearing significant health implications for the Qatari population in particular, and for this highly consanguineous region of the world in general.
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Antibacterial, antitumor and antioxidant of bioactive compounds extracted from secondary metabolites of the fungus Rhizoctonia solani Kuhn
المؤلفون: Tawfik MuhsinAbstract The aim of this study is to examine the bioactive compounds from secondary metabolites of the fungus Rhizoctonia solani against some selected strains of pathogenic bacteria. The fungus grown in a fermented culture and the filtrate was extracted in different chemical solvents. The fungal crude extract was used to examine the bioactivity against six strains of bacteria using disc diffusion method. The results showed that the fungal extract exhibited highest growth inhibition against E. coli (34 mm inhibition zone) and S. aureus (38 mm). The minimal inhibitory concentration (MIC) values were 12.5 ug/ml and 6.5 ug/ml against E. coli and S. aureus, respectively. The fungal crude extract did not show any toxicity against human red blood. A comparison between bioactivity of the fungal extract with five commercial drugs against the tested bacteria showed that the fungal extract exhibited a significant bacterial growth inhibition than the commercial drugs. Meantime, the fungal extract showed an antitumor bioactivity by using tumor cell-line of Hep2 at low concentration (0.05 mg/ml). Also the fungal extract revealed an antioxidant action by using Fe II reduction test. Chemical analysis by using FT-IR, HNMR, and GC-Mass techniques indicated that the fungal extract composed of two main chemical compounds; Malonic acid, 2, 4-dimethyl-3-yl ethyl ester with a chemical formula C12H22O4 and Molecular weight of 230 kd and Pentanedioic,2-oxo-dimethyl ester with a chemical formula C7H10O5 and molecular weight of 174 kd. It can be concluded that the fungus R. solani possesses a potential bioactive compounds as a promising agents in medical therapy.
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Symptomatic treatment approach does not appear to be effective in controlling Chlamydia trachomatis transmission
المؤلفون: Ryosuke Omori[Background] Chlamydia trachomatis (CT) is one of the most common bacterial sexually transmitted infections (STIs) worldwide, and is a major cause of pelvic inflammatory disease, infertility, and ectopic pregnancy. A recent study has found larger than expected prevalence of CT in Qatar, with a prevalence of about 5% among women attending primary health-care centers. The driver of such higher than expected prevalence is not clear. We examined whether the lack of screening programs for CT could contribute to explaining this level of prevalence. [Method] We constructed a mathematical model to examine the public health impact of different CT treatment approaches. The model was parameterized by the prevalence of CT in Qatar along with state of the art empirical evidence of CT natural history and transmission. The population was divided into different risk and age groups, and a mixing matrix was introduced to describe the mixing between these groups. The impact of treatment was assessed at endemic equilibrium. Univariate sensitivity analyses were conducted. [Results] Nearly 63% of CT infections in the population were asymptomatic. A symptomatic treatment approach, where 90% of symptomatic cases were treated, reduced CT prevalence by only 6.5%. An opportunistic screening program, where 20% of the population was screened annually for CT, reduced the prevalence by 36%. Routine screening program, where 50% of the population was screened annually for CT, reduced the prevalence by 93%. The large impact of screening on CT transmission was driven not only by the diagnosis of asymptomatic infections and treating them, but also by reducing effectively the duration of the infectious period during which infected persons can transmit the infection to other individuals. [Discussion] Our results suggest that a key contributor to the higher than expected prevalence of CT in Qatar, is the non-availability of CT-specific screening programs to detect and treat asymptomatic CT infection, such as those available in West Europe and North America. Current programs that focus on treatment of syndromic cases are missing the majority of cases. The undiagnosed infections are driving further transmissions, and a larger CT prevalence. Opportunistic targeted screening could be a meaningful starting point for CT screening programs in Qatar, with potentially routine Pap smear testing as an entry point. Our findings indicate the utility of developing STI-specific programs in Qatar as part of the large expansion of health care services in this country. Detecting CT infections and linking them with appropriate treatment channels could alleviate an unnecessary disease burden and its consequences in the population.
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Osteopontin regulates hypoxic induction of NHE1 activity in H9C2 cells
المؤلفون: Soumaya BouchouchaOsteopontin regulates hypoxic induction of NHE1 activity in H9C2 cells. Soumaya Bouchoucha, Fatima Mraiche Hypoxia, an important component of ischemia, is the result of an imbalance between oxygen supply and demand. Severe impairment of oxygen supply may result in a maladaptive cardiac phenotype. During myocardial ischemia, the Na+/H+ exchanger isoform 1 (NHE1), the main regulator of pHi, has been shown to be increased. It has been shown recently that NHE1 elevation increases Osteopontin (OPN) expression, a matricellular protein and proinflammatory cytokine that has been reported to have a protective role in ischemic injury. In this study we tested the hypothesis that hypoxic induction of NHE1 expression and subsequent alterations in H9c2 cells are mediated by OPN. H9c2 cardiomyoblasts were infected with GFP, NHE1 in the presence and absence of OPN adenoviruses following a hypoxic insult using cobalt chloride (CoCl2). Western blotting was performed to investigate the expression of OPN and NHE1. NHE1 activity was measured using BCECF-AM. H9c2 infected cells exposed to hypoxia were characterized by measuring cell viability. Inducing hypoxia for 6 hours caused a significant decrease in cell viability in H9c2 cells (GFP: 87±2.5% Vs 70.76±8.17% GFP + hypoxia; P<0.05). In NHE1 + hypoxia infected cells, viability was significantly lower than the control (NHE1 + hypoxia: 69.36±13.71% Vs 100.0 GFP + hypoxia; P<0.05). Interestingly, when overexpressing both OPN and NHE1+hypoxia, cell viability tended to increase. Compared to the control groups, CoCl2 increased the rate of recovery, which reflects the activity of NHE1, in all groups. These results were accompanied by an increase in OPN expression in the NHE1+ hypoxia infected cells (NHE1 + hypoxia: 167.36±10.01% Vs. 100.0 GFP + hypoxia; P<0.05), which validates that NHE1 activates the expression of OPN under hypoxic conditions. These results reveal a suspected role of osteopontin in protecting cell against ischemic injury owing to the increase of NHE1 expression and activity. Taken together, identified osteopontin may function as a survival factor against hypoxic induction of NHE1 cell death. Keywords: NHE1, Osteopontin, hypoxia.
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Output-feedback sliding mode control for a nonlinear multicompartment respiratory system with amplitude and integral input constraints
المؤلفون: Nader MeskinAcute respiratory failure is one of the major causes for concern in intensive care units (ICU). It is a condition that occurs when fluid builds up in the air sacs in the lungs. When this happens the lungs cannot release oxygen into the blood and get rid of carbon dioxide from the body. The lack of oxygen in the blood will cause the organs to malfunction and in severe cases could lead to failure of vital organs such as heart and brain. Patients with acute respiratory failure are usually supported by the mechanical ventilator. The goal of mechanical ventilation is to ensure adequate ventilation, which involves a magnitude of gas exchange that leads to the desired blood level of carbon dioxide, and adequate oxygenation, which involves a blood concentration of oxygen that will ensure proper function of vital organs. A plausible reference lung volume pattern, which corresponds to an optimal patient outcome, is specified by clinical personnel and the task of automated mechanical ventilation is to apply appropriate input pressure so that the output from the system is able to track the given reference voulme pattern. One of the main challenges in mechanical ventilation that needs to be carefully considered is that the applied pressure cannot be arbitrarily large since large applied pressure could potentially damage the lungs, and hence, worsen patients outcome. Another challenge in designing an efficient control algorithm for mechanical ventilation is that the parameters characterizing the dynamics of the lungs, that is, the lung resistances and lung compliances, vary from patient to patient as well as within the same patient under different conditions. Furthermore, the volume of each compartment of the lungs cannot be directly measured and only the total volume of the lungs is available. Therefore, a robust control methodology, which only uses output information and limited applied pressure, is needed in order to design an efficient control algorithm for automated mechanical ventilation. In this research work, we propose an output-feedback sliding mode control methodology for a nonlinear multicompartment respiratory system with amplitude and integral input constraints. The amplitude input constraint is needed to ensure that the applied pressure is not too large, as not to damage the lungs, while the integral input constraint enforces the upper bound on the amount of work done by the ventilator. The proposed controller only uses output information (i.e., the total volume of the lungs) and automatically adjusts the applied input pressure so that the system is able to track a given reference volume pattern in the presence of parameter uncertainty (i.e., modeling uncertainty of the lung resistances and lung compliances) and system disturbances. A Lyapunov-based approach is presented for the stability analysis of the system and the proposed control framework is applied to a two compartment lung model to show the efficacy of the proposed control method.
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Hypertension in Middle-Eastern Arab and South-Asian patients hospitalized with atrial fibrillation: From a 20-year registry in Qatar (1991-2010)
المؤلفون: Amar SalamBackground: Most of available literature on atrial fibrillation (AF) is based on studies in the developed world and included mainly Caucasian patients. Data about AF in other ethnicities is very limited. The aim of the current study is to evaluate the effect of hypertension (HTN) in Middle-eastern Arab and South-Asian patients hospitalized with AF from a 20 year national registry in a Middle-Eastern country. Methods: Retrospective analysis of all patients hospitalized with AF in Qatar from 1991 through 2010 was made. Patients were divided into two groups according to the presence or absence of HTN on presentation. Clinical characteristics and outcomes were analyzed. Results: During the 20-years period, 3850 patients were hospitalized for AF; 1483 (38.3%) had HTN on presentation while 2367 (61.5%) had no HTN. HTN patients were 11 years older, had significantly more prevalence of diabetes mellitus, chronic kidney disease and dyslipidemia on presentation. Underlying coronary artery disease and heart failure were significantly more common in patients with HTN while valvular and rheumatic heart disease was more common in non-HTN patients. The in-hospital mortality and stroke rates were significantly higher in HTN patients (5.3% versus 3.5%, and 0.7% versus 0.2% respectively, p= 0.001) [table]. Conclusions: Our study demonstrates that in a cohort of Middle-eastern Arab and South-Asian patients hospitalized with AF, HTN is significantly associated with worse in-hospital outcomes. Our study underscores the need to study AF in different ethnicities.
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The utilization of next generation sequencing to reveal genetic anomalies among familial myeloproliferative neoplasms cases within the State of Qatar
المؤلفون: Nader Al-DewikBackground: Myeloproliferative Neoplasms (MPNs) are clonal hematopoietic disorders, classified into three different phenotypes Polycythemia Vera (PV), Essential Thrombocytosis (ET) and Primary Myelofibrosis (PMF). This disorder is associated with the presence Jak2V617F mutation in 90% of PV and 50% of ET and PMF patients as well as other mutations such as Jak2 exon 12 and MPL. However, there are still significant numbers of MPNs cases that are negative to most common genetic anomalies and many mutations are still unknown Aim: To identify and elucidate genetic defects causing MPNs that could serve as disease biomarker. Methods: 7 MPN patients and healthy individuals from 3 consanguineous families were consented into the study. Peripheral blood samples were collected from 6 patients and 4 healthy individuals. Further, genomic DNA was extracted and used for multiplex PCR amplification of 190 amplicons targeting 739 cancer associated mutations in 604 loci from 46 key cancer genes, using the Ion AmpliSeq™ Kit. Next Generation Sequencing (NGS) was performed through the Ion Torrent Personal Genome Machine using the 318 chip and was analyzed with the Torrent Suite Software (Full list of mutations targeted can be found at http://www.bcm.edu/geneticlabs/index.cfm?pmid=21681). Mutation details were obtained from the Catalogue Of Somatic Mutations In Cancer (COSMIC) database. A human genome (hg) 19 DNA sequence (http://www.ncbi.nlm.nih.gov/refseq/rsg/) was used as references for this panel of genes. The nomenclature of mutations is based on the convention recommended by the Human Genome Variation Society (http://www.hgvs.org/mutnomen/). The confirmation of NGS data was performed using RQ-PCR or Sanger sequencing and Jak2 exon 12 mutations were studied. Results: Out of four PV patients, three were positive for the JAK2 V617F mutation. One patient had mutations in PDGFRA 838-840delGLA, APC Q1285fs, NPM1 Splice Site Loss and PTEN S10N. The second patient had mutations in KIT M541L, KDR Q472H, TP53 P72R, while the third patient had PI3KCA I391M, KIT M541L, KDR Q472H and P53 P72R mutations. The fourth patient was negative to the JAK2 V617F mutation, but showed PDGFR A838-840delGLA and SMARCB1 T72K mutations. Out of three ET patients, one patient was positive for JAK2 V617F, SMARCB1 T72K, IDH1 K115Q and PDGFRA 838-840delGLA mutations. Two patients were negative for the JAK2 V617F and MPL mutations, one patient had mutations in PDGFRA 838-840delGLA, APC Q1285fs and SMAD4 198-200delPAL, while the other patient had mutations in CDKN2A S73R, APC Q1285fs and PDGFRA 838-840delGLA. Furthermore, the PDGFRA 838-840delGLA and APC Q1285fs mutations were also found in healthy individuals. Conclusion: This study was able to identify a list of deleterious somatic mutations such as missense and frame shift mutations, in-frame deletions, splice loss sites and Single Nucleotide Variation (SNV) in MPNs patients and healthy individuals. Our preliminary results suggest that the MPNs patients in Qatar have complex mutations. Evidences show that there exists a possibility of the disease arising out of the accumulation of genetic alteration and not as the consequence of a single genetic event. This could possibly be due to the high rate of consanguineous marriages in Qatar i.e. the "Founder Effect".
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Development Of A Novel Method For The Selective Detection Of Erythrocyte Membrane Bound Proteins
المؤلفون: Morana JaganjacBlood doping still remains as a performance enhancement strategy misused by athletes . Blood doping is the practice of boosting the number of red blood cells in the bloodstream by means of either blood transfusion of an individual or by administration of erythropoietin, in order to increase the oxygen carrying capacity of the blood. There is no direct method currently for the detection of autologous transfusion, leaving this an open issue in antidoping strategies. Recently it was reported that some proteins might represent suitable markers for in vitro aging of erythrocytes, particularly those proteins that can be detected in the membrane. Thus, this study was conducted on erythrocytes isolated from fresh and 20-day old blood samples of the same individual, with a particular focus on the erythrocyte membrane bound proteins. Isolated proteins were separated into 12 fractions on the Gelfree system, digested with trypsin and separated using a nanoLC. Eluted peptides were then spotted on a MALDI plate with MALDI spotter and detected on MALDI-TOF/TOF instrument. Afterwards, the MS/MS data for these peptides were identified using SwissProt and Mascot database search. The results have shown significant differences in the peptides when comparing fresh and stored blood samples, revealing several potential targets that can be used as markers for blood doping detection. The next step is to prove the reproducibility of the results on a larger number of specimens as an initial validation step.
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Calcineurin-NFAT signaling pathway mediates NHE1 induced cardiac hypertrophy
المؤلفون: Mohamed Salem MlihCalcineurin-NFAT Signaling Pathway Mediates NHE1 Induced Cardiac Hypertrophy Mohamed Mlih, Fatima Mraiche College of Pharmacy, Qatar University, Doha, Qatar In the myocardium, the Na+/H+ exchanger isoform 1 (NHE1), a plasma membrane protein that regulates intracellular pH has been shown to be critical in the development of cardiac hypertrophy. Inhibition of NHE1 activity/expression has previously been demonstrated to produce cardioprotective effects. Recent reports have reported that transgenic mice overexpressing active NHE1 developed spontaneous cardiac hypertrophy in association with elevated levels of osteopontin (OPN). Osteopontin is a secreted protein involved in many physiological pathways including bone formation, immune response, vascularization and cardiac hypertrophy. The physiological pathway in which active NHE1 induces OPN expression in the heart remains unknown. Recently, NHE1 was described as a key regulator of the calcineurin-NFAT pathway. The calcineurin-NFAT pathway is a hypertrophic pathway induced by intracellular increase in calcium concentration that induces NFAT translocation to the nucleus. In the nucleus, NFAT interacts with the transcription factor GATA-4 and together activate hypertrophic gene. Our hypothesis is that NHE1 through the calcineurin/Nfat pathway induces OPN expression leading to cardiac hypertrophy. To verify this hypothesis , rat cardiomyoblasts (H9c2 cells) were infected with activate NHE1 adenovirus in the presence and absence of a calcineurin inhibitor, FK506 . H9c2 cells infected with active NHE1 showed an increase of NHE1 activity (NHE1: 376.5%) and exhibit a 1.6 fold increase in cell area compared to the control, which was attenuated in the presence of FK506. Our preliminary results show that NHE1 activation increases osteopontin protein expression. In addition, H9c2 cells infected with active NHE1 also demonstrate a significant activation of the transcription factor GATA-4 (NHE1: 149% ±28% , p<0.05). The activation of GATA-4 induced by active NHE1 is inhibited by FK506 treatment. In conclusion, NHE1 through the calcineurin/NFAT pathway induces cardiac hypertrophy in H9c2 cells. This new finding will give us a better understanding of signaling pathway mediating NHE1 induced cardiac hypertrophy and allow us to identify alternative therapeutic targets for the treatment heart failure.
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