B. Santhosh Kumar

A comparative clinical survey of the prevalence of refractive errors and eye diseases in urban and rural school children

OBJECTIVE To assess the prevalence of refractive error and common ocular diseases in school-aged children in urban and rural populations in and around Hyderabad, India. DESIGN Population-based, cross-sectional study. PARTICIPANTS A total of 3314 school children, 1789 from urban areas and 1525 from rural areas. METHODS The examination included visual acuity measurements, retinoscopy and autorefraction under cycloplegia, examination of the anterior segment and external eye, and ocular motility evaluation. RESULTS In the urban group the prevalence of uncorrected presenting and best-corrected visual impairment (< or = 20/40 in the better eye) was 9.8%, which dropped to 7.1% with presenting vision and was further reduced to 1.1% with best-corrected visual acuity. Uncorrected visual acuity in the rural group was 6.6%, which dropped to 3.3% with presenting vision and was further reduced to 2.5% with best-corrected visual acuity. The prevalence of refractive error was greater (25.2%) in the urban than the rural group (8%). Myopia measured with autorefraction was observed in 51.4% of urban children and 16.7% in rural children. Increased literacy rate, duration of study hours, and older age of the child were found to have contributed more to the prevalence of myopia in the urban group. Hyperopia with autorefraction was found to be 3.3% in the urban and 3.1% in the rural group. Hyperopia was associated with younger age in the study group. Trachoma was the leading cause of ocular morbidity in the rural group (3.5%) compared with the urban group (0.16%). Night blindness was reported in 3.2% of children in the rural group and 0.33% in the urban group. Vitamin A deficiency, low socio-economic status, and poor personal and environmental hygienic practice were found to have a positive correlation with ocular morbidity among rural group children. CONCLUSIONS Provision of health education, periodic visual screening programs, and primary eye care by trained health care personnel in the elementary schools will prevent the prevalence of refractive errors and common ocular diseases in school children.

Anti-unlcer and antimicrobial activities of sodium selenite against Helicobacter pylori: in vitro and in vivo evaluation.

Abstract We examined sodium selenite, an inorganic selenium supplement, for its ulcer healing properties and antimicrobial activity against gastric pathogen Helicobacter pylori. Minimum inhibitory concentrations (MIC) were determined using disk diffusion and flow cytometry. The studies were performed over a concentration range of 1 μg/ml to 500 μg/ml sodium selenite. Mild activity was seen at 10 μg/ml and 50 μg/ml, a moderate response at 100 μg/ml and strong response at 500 μg/ml with a MIC value of 10 μg/ml. The compound was found to be active at low pH without any resistance after 10 passages. Flow cytometry data showed a characteristic shift of the viability peak in comparison with the control, thereby confirming the bactericidal effects of sodium selenite. Sodium selenite administered in Wistar rats, pre-ulcerated with naproxen and infected with H. pylori, showed ulcer healing and anti-H. pylori activity at a concentration range of 10–50 μg/rat; however concentrations of 100 μg/rat and 500 μg/rat were found to be toxic in the in vivo studies. In conclusion, sodium selenite shows both ulcer healing and anti-H. pylori activity at a low concentration (10 μg/rat) without toxicity.

Hepatoprotective, immunomodulatory, and anti-inflammatory activities of selenocystine in experimental liver injury of rats.

The study was evaluated to investigate the efficacy of selenocystine (CysSeSeCys), a well-known organoselenium compound, on the prevention of carbon tetrachloride (CCl4)-induced acute hepatic injury in Wistar rats. Forty healthy male Wistar rats were utilized in this study. Acute hepatotoxicity was induced by CCl4 intoxication in rats. Serum biological analysis, oxidative stress, immune parameters, and gene expression of COX-2 and CYP2E1 were carried out. Pretreatment of CysSeSeCys prior to CCl4 administration significantly prevented an increase in serum hepatic enzymatic activities. In addition, pretreatment of CysSeSeCys significantly prevented the formation of ROS, MDA, depletion of glutathione, and alteration of antioxidant enzyme activities in the liver of CCl4-intoxicated rats. This study also revealed that pretreatment with CysSeSeCys normalized the levels of interleukin 6 and10, IgG, and CD4 cell count. Pretreatment of CysSeSeCys significantly reversed COX-2 inflammatory response and the upregulation of CYP2E1 expression as well. Histopathological changes induced by CCl4 were also significantly attenuated by CysSeSeCys pretreatment. CysSeSeCys has a potent hepatoprotective effect on CCl4-induced liver injury in rats through its antioxidative, immunomodulatory and anti-inflammatory activity.

Anti-hemolytic and Peroxyl Radical Scavenging Activity of Organoselenium Compounds: An In Vitro Study

Selenium-containing amino acids, selenocystine (CysSeSeCys), methylselenocysteine (MeSeCys), and selenomethionine (SeMet) have been examined for anti-hemolytic and peroxyl radical scavenging ability. Effect of these compounds on membrane lipid peroxidation, release of hemoglobin, and loss of intracellular K+ ion as a consequence of peroxyl radicals-induced oxidation of human red blood cells were used to evaluate their anti-hemolytic ability. The peroxyl radicals were generated from thermal degradation of 2,2′-azobis(2-methylpropionamidine) dihydrochloride. Significant delay (teff) was observed in oxidative damage in the presence of the selenium compounds. From the IC50 values for the inhibition of hemolysis, lipid peroxidation, and K+ ion leakage, the relative anti-hemolytic ability of the compounds were found to be in the order of CysSeSeCys > MeSeCys > SeMet. The anti-hemolytic abilities of the compounds, when compared with sodium selenite (Na2SeO3) under identical experimental conditions, were found to be better than Na2SeO3. Relative rate constants estimated for the reaction of MeSeCys and SeMet with peroxyl radicals by competition kinetics using ABTS2− as a reference confirmed that all the compounds are efficient peroxyl radical scavengers. Comparison of the GPx-like activity of these compounds, by NADPH–GSH reductase coupled assay, indicated that CysSeSeCys exhibits the highest activity. Based on these results, it is concluded that among the compounds examined, CysSeSeCys, possessing the ability to reduce peroxyl radicals and hydroperoxides showed efficient anti-hemolytic activity.

Relevance of Helicobacter pylori genotypes in gastric pathology and its association with plasma malondialdehyde and nitric oxide levels

Persistent infection with Helicobacter pylori confers an increased risk of peptic ulceration and gastric adenocarcinoma. Reactive oxygen and nitrogen species play a crucial role in the progression from normal gastric mucosa to cancer. The aim of the present study was to investigate the plasma malondialdehyde and nitric oxide levels in H. pylori related gastroduodenal diseases and associate their levels with gastric pathology and genotypes of H. pylori. Malondialdehyde and nitric oxide levels in plasma samples of 250 subjects were spectrophotometrically determined. Subsequently, genotypic and histopathological assessment was performed in gastric biopsies obtained during endoscopy. The levels of MDA and NO exceeded in subjects infected with genotype-1 of Hp than those with other genotypes suggesting more precise interaction of highly virulent strains of Hp in eliciting severe tissue damage. In conclusion, the study demonstrates close relationship between the plasma malondialdehyde and nitric oxide levels, gastric histopathology and genotypes of H. pylori.

Obstructive Sleep Apnea and the Metabolic Syndrome: Clinical Profiles and Relationships

Abstract Obstructive sleep apnea syndrome (OSA) is characterized by repetitive collapse of the upper airway during sleep. The resultant chronic intermittent hypoxia and recurrent arousals underlie many of its deleterious effects. The clustering of cardiovascular risk factors such as elevated blood pressure, hyperglycemia, and dyslipidemia with central obesity has been designated the metabolic syndrome (MS ; Syndrome X) . This chapter examines the clinical derangements manifesting as a result of the interplay between MS and OSA in adult persons, and explores some of the underlying pathophysiologic mechanisms.