ABSTRACT Heavy metal pollution has become one of the most serious environmental problems today. B... more ABSTRACT Heavy metal pollution has become one of the most serious environmental problems today. Biological methods such as biosorption or bioaccumulation strategies for the removal of metals ions may provide an attractive alternative to existing technologies. Microorganisms, as heavy metal bioadsorbents, offer a new alternative for removal of toxic or valuable metals in water. Saccharomyces cerevisiae has received increasing attention due to its unique nature and capacity for metal sorption. It is one of the most promising biosorbents capable of removing metal ions from aqueous solution. Manganese occurs naturally in many surface water and groundwater sources and in soils that may erode into this water. Eleven S. cerevisiae yeast strains in alive and dead forms were screened for biosorption and bioaccumulation of manganese from artificial aqueous solution. S. cerevisiae F-25 in alive form was found to be highly biosorbent for Mn+2 and biosorbed 22.5 mg Mn+2/gm yeast biomass. Optimization of environmental conditions reveals that optimum concentrations for maximum Mn2+ biosorption by S. cerevisiae F-25 in alive form were 4.8 mg Mn2+/l after 30 min at pH 7, agitation 150 rpm and yeast biomass concentration 0.1 gm/l at 30 °C. Competition of Mn+2 with other heavy metals shows that Mn+2 in control sample without, any other heavy metals added in solution at 4.8 mg/l of the biosorbed Mn+2 was 41.3 mg/g biomass. Addition of other heavy metals affects the percent of biosorbed Mn+2.
Rapid Assessment for the Avoidable Blindness (RAAB) was conducted in Qatar during 2009. We presen... more Rapid Assessment for the Avoidable Blindness (RAAB) was conducted in Qatar during 2009. We present the prevalence and determinants of visual disabilities and status of cataract among citizens aged 50 years and older. Residents of randomly selected houses and clusters participated in the survey. Opticians noted the presenting and the best corrected vision of participants from 49 clusters. Ophthalmologists examined participants with additional instruments like bio-microscope, digital camera, auto-perimeter and auto-refractor in a mobile van. World Health Organization recommended principal cause of blindness (Visual acuity [VA] < 3/60 in better eye), Severe visual impairment (SVI) (<6/60), low vision (VA < 6/18) and unilateral blindness (VA < 3/60) were designated. Persons with VA < 6/18 and cataract were interviewed to calculate coverage and barriers for cataract surgeries. Age sex adjusted prevalence of visual disabilities and their 95% Confidence Intervals (CI) were estimated. We examined 2,433 (97.3%) participants. The age sex adjusted prevalence of bilateral blindness was 1.28% [95% CI 1.22-1.35], SVI (1.67%), low vision (3.66%) and unilateral blindness (3.61%) in 50 years and older population. Female and older age groups were significant risk factors of visual disabilities. Cataract and glaucoma were the main causes of visual disabilities. The coverage of cataract services was 68.2%. Believing that cataract as an aging process (25) and adequate vision in the fellow eye (15) were the reasons for delay in surgery. To reduce avoidable blindness, un-operated cataract should be addressed. Primary and secondary eye care systems should be strengthened to improve the care of blinding eye diseases in Qatar.
We present the prevalence and determinants of diabetic retinopathy (DR) in persons 40 years and o... more We present the prevalence and determinants of diabetic retinopathy (DR) in persons 40 years and older with diabetes in Qatar. This community-based survey was held in 2009 at 49 randomly selected clusters. Demographic details and history of diabetes mellitus (DM) and its management were collected by nurses. Ophthalmologists examined the retina by slit-lamp biomicroscopy using +90 D lens and/or indirect ophthalmoscopy. Digital photographs of retina were obtained. The best-corrected visual acuity of each eye was noted. Diabetic retinopathy was graded as mild, moderate, or severe nonproliferative DR, proliferative DR, or diabetic macular edema. We examined 540 (97.3%) participants with DM. Diabetes mellitus status of 487 persons could be confirmed from medical records. The age- and sex-adjusted prevalence of DR among the diabetic population 40 years and older was 23.5% (95% confidence interval [CI] 19.7-27.3), with 8192 cases of DR among patients with DM. Longer duration of diabetes (odds ratio 1.14 [95% CI 1.10-1.19]) and poor glycemic control (odds ratio 1.12 [95% CI 1.02-1.23]) were risk factors for DR. Awareness of regular eye checkup was found in 62% of participants. Only 20% of persons with sight-threatening DR had undergone laser treatment in at least 1 eye. Visual acuity in the better eye was 6/6 to 6/18 in 90% of persons with DR. Universal and periodic eye screening of patients with diabetes is recommended in Qatar. Health promotion for primary prevention and resource review are needed for early detection and management of sight-threatening DR.
Overexpression of SLMAP gene has been associated with diabetes and endothelial dysfunction of mac... more Overexpression of SLMAP gene has been associated with diabetes and endothelial dysfunction of macro- and micro-blood vessels. In this study our primary objective is to explore the role of SLMAP gene polymorphisms in the susceptibility of type 2 diabetes (T2DM) with or without diabetic retinopathy (DR) in the Qatari population. A total of 342 Qatari subjects (non-diabetic controls and T2DM patients with or without DR) were genotyped for SLMAP gene polymorphisms (rs17058639 C > T; rs1043045 C > T and rs1057719 A > G) using Taqman SNP genotyping assay. SLMAP rs17058639 C > T polymorphism was associated with the presence of DR among Qataris with T2DM. One-way ANOVA and multiple logistic regression analysis showed SLMAP SNP rs17058639 C > T as an independent risk factor for DR development. SLMAP rs17058639 C > T polymorphism also had a predictive role for the severity of DR. Haplotype Crs17058639Trs1043045Ars1057719 was associated with the increased risk for DR among Qataris with T2DM. The data suggests the potential role of SLMAP SNPs as a risk factor for the susceptibility of DR among T2DM patients in the Qatari population.
ABSTRACT Heavy metal pollution has become one of the most serious environmental problems today. B... more ABSTRACT Heavy metal pollution has become one of the most serious environmental problems today. Biological methods such as biosorption or bioaccumulation strategies for the removal of metals ions may provide an attractive alternative to existing technologies. Microorganisms, as heavy metal bioadsorbents, offer a new alternative for removal of toxic or valuable metals in water. Saccharomyces cerevisiae has received increasing attention due to its unique nature and capacity for metal sorption. It is one of the most promising biosorbents capable of removing metal ions from aqueous solution. Manganese occurs naturally in many surface water and groundwater sources and in soils that may erode into this water. Eleven S. cerevisiae yeast strains in alive and dead forms were screened for biosorption and bioaccumulation of manganese from artificial aqueous solution. S. cerevisiae F-25 in alive form was found to be highly biosorbent for Mn+2 and biosorbed 22.5 mg Mn+2/gm yeast biomass. Optimization of environmental conditions reveals that optimum concentrations for maximum Mn2+ biosorption by S. cerevisiae F-25 in alive form were 4.8 mg Mn2+/l after 30 min at pH 7, agitation 150 rpm and yeast biomass concentration 0.1 gm/l at 30 °C. Competition of Mn+2 with other heavy metals shows that Mn+2 in control sample without, any other heavy metals added in solution at 4.8 mg/l of the biosorbed Mn+2 was 41.3 mg/g biomass. Addition of other heavy metals affects the percent of biosorbed Mn+2.
Rapid Assessment for the Avoidable Blindness (RAAB) was conducted in Qatar during 2009. We presen... more Rapid Assessment for the Avoidable Blindness (RAAB) was conducted in Qatar during 2009. We present the prevalence and determinants of visual disabilities and status of cataract among citizens aged 50 years and older. Residents of randomly selected houses and clusters participated in the survey. Opticians noted the presenting and the best corrected vision of participants from 49 clusters. Ophthalmologists examined participants with additional instruments like bio-microscope, digital camera, auto-perimeter and auto-refractor in a mobile van. World Health Organization recommended principal cause of blindness (Visual acuity [VA] < 3/60 in better eye), Severe visual impairment (SVI) (<6/60), low vision (VA < 6/18) and unilateral blindness (VA < 3/60) were designated. Persons with VA < 6/18 and cataract were interviewed to calculate coverage and barriers for cataract surgeries. Age sex adjusted prevalence of visual disabilities and their 95% Confidence Intervals (CI) were estimated. We examined 2,433 (97.3%) participants. The age sex adjusted prevalence of bilateral blindness was 1.28% [95% CI 1.22-1.35], SVI (1.67%), low vision (3.66%) and unilateral blindness (3.61%) in 50 years and older population. Female and older age groups were significant risk factors of visual disabilities. Cataract and glaucoma were the main causes of visual disabilities. The coverage of cataract services was 68.2%. Believing that cataract as an aging process (25) and adequate vision in the fellow eye (15) were the reasons for delay in surgery. To reduce avoidable blindness, un-operated cataract should be addressed. Primary and secondary eye care systems should be strengthened to improve the care of blinding eye diseases in Qatar.
We present the prevalence and determinants of diabetic retinopathy (DR) in persons 40 years and o... more We present the prevalence and determinants of diabetic retinopathy (DR) in persons 40 years and older with diabetes in Qatar. This community-based survey was held in 2009 at 49 randomly selected clusters. Demographic details and history of diabetes mellitus (DM) and its management were collected by nurses. Ophthalmologists examined the retina by slit-lamp biomicroscopy using +90 D lens and/or indirect ophthalmoscopy. Digital photographs of retina were obtained. The best-corrected visual acuity of each eye was noted. Diabetic retinopathy was graded as mild, moderate, or severe nonproliferative DR, proliferative DR, or diabetic macular edema. We examined 540 (97.3%) participants with DM. Diabetes mellitus status of 487 persons could be confirmed from medical records. The age- and sex-adjusted prevalence of DR among the diabetic population 40 years and older was 23.5% (95% confidence interval [CI] 19.7-27.3), with 8192 cases of DR among patients with DM. Longer duration of diabetes (odds ratio 1.14 [95% CI 1.10-1.19]) and poor glycemic control (odds ratio 1.12 [95% CI 1.02-1.23]) were risk factors for DR. Awareness of regular eye checkup was found in 62% of participants. Only 20% of persons with sight-threatening DR had undergone laser treatment in at least 1 eye. Visual acuity in the better eye was 6/6 to 6/18 in 90% of persons with DR. Universal and periodic eye screening of patients with diabetes is recommended in Qatar. Health promotion for primary prevention and resource review are needed for early detection and management of sight-threatening DR.
Overexpression of SLMAP gene has been associated with diabetes and endothelial dysfunction of mac... more Overexpression of SLMAP gene has been associated with diabetes and endothelial dysfunction of macro- and micro-blood vessels. In this study our primary objective is to explore the role of SLMAP gene polymorphisms in the susceptibility of type 2 diabetes (T2DM) with or without diabetic retinopathy (DR) in the Qatari population. A total of 342 Qatari subjects (non-diabetic controls and T2DM patients with or without DR) were genotyped for SLMAP gene polymorphisms (rs17058639 C > T; rs1043045 C > T and rs1057719 A > G) using Taqman SNP genotyping assay. SLMAP rs17058639 C > T polymorphism was associated with the presence of DR among Qataris with T2DM. One-way ANOVA and multiple logistic regression analysis showed SLMAP SNP rs17058639 C > T as an independent risk factor for DR development. SLMAP rs17058639 C > T polymorphism also had a predictive role for the severity of DR. Haplotype Crs17058639Trs1043045Ars1057719 was associated with the increased risk for DR among Qataris with T2DM. The data suggests the potential role of SLMAP SNPs as a risk factor for the susceptibility of DR among T2DM patients in the Qatari population.
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Papers by Maha Elshafei