Journal/Magazine Articles
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This collection contains original research articles, review articles and case reports published in local and international peer reviewed journals by the staff members of the Faculty of Medicine
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Item Physical activity tracking among Sri Lankan adults: findings from a 7-year follow-up of the Ragama Health Study(SAGE Publications, 2021) Pinidiyapathirage, J.; Kasturiratne, A.; Bennie, J.A.; Pathmeswaran, A.; Biddle, S.J.H.; de Silva, H.J.; Chackrewarthy, S.; Dassanayake, A.S.; Ranawaka, U.; Kato, N.; Wickremasinghe, A.R.ABSTRACT: Limited data are available on physical activity tracking among adults in low- and middle-income countries. Using a longitudinal design, we assessed trends and correlates of physical activity among Sri Lankan adults. Individuals selected through age-stratified random sampling, were screened initially in 2007 (n = 2986) and reevaluated in 2014 (n = 2148). On both occasions, structured interviews and clinical measurements were completed. Approximately 40% of the participants engaged in recommended levels of physical activity both at baseline and follow-up. One-fifth reported increased physical activity at follow-up, a similar proportion reported being persistently inactive or a reduction in physical activity. In the adjusted analysis, being persistently active was associated with male sex, a lower educational level and income, being free of any chronic disease conditions, better self-rated health, and sitting time <8 hours. Our findings support public health interventions to help maintain recommended physical activity levels over time, particularly for subgroups at high-risk of physical inactivity. KEYWORDS: Sri Lanka; lower middle-income countries; non-communicable diseases; physical activity; population studies.Item Evaluation of the hypoglycemic and hypolipidemic effects of an ethylacetate fraction of Artocarpus heterophyllus (jak) leaves in streptozotocin-induced diabetic rats(Medknow Publications, 2010) Chackrewarthy, S.; Thabrew, M.I.; Weerasuriya, M.K.; Jayasekera, S.Aqueous extracts of mature leaves of Artocarpus heterophyllus (jak) are used by traditional medical practitioners in Sri Lanka and India for the treatment of diabetes. This study was conducted to investigate the hypoglycemic and hypolipidemic effects of an ethylacetate (EA) fraction of the mature leaves of A. heterophyllus in a streptozotocin (STZ) induced diabetic rat model. In normoglycemic rats, administration of a single dose (20 mg/kg) of the EA fraction resulted in a significant (P < 0.05) reduction in the fasting blood glucose concentration and a significant improvement in glucose tolerance (P < 0.05), compared to the controls. In STZ-induced diabetic rats, chronic administration of the EA fraction of A. heterophyllus leaves daily for 5 weeks resulted in a significant lowering of serum glucose, cholesterol and triglyceride (TG) levels. Compared to control diabetic rats, the extract-treated rats had 39% less serum glucose, 23% lower serum total cholesterol and 40% lower serum TG levels and 11% higher body weight at the end of the fifth week. The percentage reductions in the serum parameters mediated by the test fraction were comparable with those produced by glibenclamide (0.6 mg/kg), the reference drug used in this study. It can be concluded that the EA fraction of A. heterophyllus leaves contains one or more hypoglycemic and hypolipidemic principles which have the potential to be developed further for the treatment of diabetes specifically associated with a hyperlipidemic stateItem Common variants at the GCK, GCKR, G6PC2-ABCB11 andMTNR1B loci are associated with fasting glucose in two Asian populations(Springer-Verlag, 2010) Takeuchi, F.; Katsuya, T.; Chackrewarthy, S.; Yamamoto, K.; Fujioka, A.; Serizawa, M.; Fujisawa, T.; Nakashima, E.; Ohnaka, K.; Ikegami, H.; Sugiyama, T.; Nabika, T.; Kasturiratne, A.; Yamaguchi, S.; Kono, S.; Takayanagi, R.; Yamori, Y.; Kobayashi, S.; Ogihara, T.; de Silva, A.; Wickremasinghe, R.; Kato, N.Item Prevalence and risk factors for non-alcoholic fatty liver disease among adults in an urban Sri Lankan population(Wiley-Blackwell, 2009) Dassanayake, A.S.; Kasturiratne, A.; Rajindrajith, S.; Kalubowila, U.; Chackrewarthy, S.; de Silva, A.P.; Makaya, M.; Mizoue, T.; Kato, N.; Wickremasinghe, A.R.; de Silva, H.J.BACKGROUND AND AIMS: Non-alcoholic fatty liver disease (NAFLD) is an emerging problem in the Asia-Pacific region. However, its prevalence and risk factors in Asian (especially South Asian) communities is poorly studied. In this study, the aim was to determine the community prevalence and risk factors for NAFLD among adults in an urban Sri Lankan population. METHODS: The study population consisted of 35-64-year-old adults, selected by stratified random sampling. NAFLD was diagnosed on established ultrasound criteria for fatty liver, safe alcohol consumption (< 14 units/week for men, < 7 units/week for females) and absence of hepatitis B and C markers. Blood pressure (BP) and anthropometric measurements were made, and fasting glucose, glycosylated hemoglobin, serum lipids, fasting serum insulin and serum alanine aminotransferase (ALT) were determined. RESULTS: Of the 2985 study participants, 974 (32.6%) had NAFLD (605 [62.1%] women, mean age 52.8 years [standard deviation, 7.3]). On multivariate analysis, obesity, acanthosis nigricans, insulin resistance, elevated diastolic BP, fasting plasma glucose, plasma triglycerides, and ALT twice the upper limit of the reference range or more were independently associated with NAFLD. CONCLUSION: The prevalence of NAFLD among adults in this urban Sri Lankan community is high and is strongly associated with constituent features of the metabolic syndrome.Item Erythrocyte antioxidant enzymes in patients with cataract(Institute for Clinical Science., 2006) Chandrasena, L.G.; Chackrewarthy, S.; Perera, P.T.; de Silva, D.The pathogenesis of cataract has been found to be influenced by a number of factors including oxidative stress. Catalase, glutathione peroxidase (GPX), and superoxide dismutase (SOD) are some of the antioxidant enzymes that protect the body from oxidative damage. The present study investigates the activities of erythrocyte catalase, GPX, and SOD with respect to senile cataract (non-diabetic cataract) and osmotic cataract (diabetic cataract) in a Sri Lankan population. One hundred and two non-diabetic subjects (50 with cataract and 52 non-cataract) and 106 diabetic subjects (56 with cataract and 50 non-cataract) were recruited into the study. Erythrocyte catalase, GPX, and SOD activities were assayed and the data were analysed by t-test (p <0.05 for significance). In the non-diabetic group, significantly low levels of catalase, GPX, and SOD activities were associated with cataract when compared with non-cataract. No significant changes in catalase, GPX, and SOD activities were observed in the diabetic group between cataract and non-cataract. Senile cataract (non-diabetic cataract) was associated with significantly low levels of erythrocyte catalase, GPX, and SOD when compared with osmotic cataract (diabetic cataract). Positive correlations were observed between catalase and SOD (r = 0.75), catalase and GPX (r = 0.63), and SOD and GPX (r = 0.59) in subjects with senile cataracts. Our results indicate that erythrocyte antioxidant enzyme levels are decreased in senile cataract as opposed to osmotic cataract. Assays of these erythrocyte enzyme activities could provide a marker to identify individuals predisposed to senile cataract.Item The Effect of Cassia auriculata and Cardiospermum halicacabum teas on the steady state blood level and toxicity of carbamazepine(Elsevier, 2004) Thabrew, M.I.; Munasinghe, C.; Chackrewarthy, S.; Senarath, S.A study was conducted using male Wistar rats as the experimental model, to compare the effects of concurrent administration of herbal tea prepared from dried flowers of Cassia auriculata or aerial parts of Cardiospermum halicacabum and carbamazepine, on (a). steady state serum levels of the prescription drug, and (b). changes in toxicity (as assessed by changes in general behaviour, haematological parameters, and liver and kidney function) that may occur due to drug interaction. Results demonstrate that in rats receiving the Cassia auriculata tea and carbamazepine, the blood levels of the prescription drug were significantly enhanced by 47.1% (P<0.04), when compared with the levels in animals receiving only carbamazepine for the same time period, with no apparent changes in toxicity. In animals receiving the Cardiospermum halicacabum tea, there were no significant changes in the blood levels of carbamazepine or drug-related toxicity. Cassia auriculata tea has therefore the potential to influence the bioavailability of carbamazepine, and hence its therapeutic actions. Concurrent ingestion of carbamazepine with herbal teas containing Cassia auriculata is therefore best avoided by patients under treatment for epilepsy.Item Possible interaction of herbal tea and carbamazepine(De Gruyter, 2003) Thabrew, M.I.; Munasinghe, T.M.J.; Chackrewarthy, S.; Senarath, S.A study was conducted using Wistar rats to determine the effect of concurrent administration of a herbal tea prepared from dried flowers of Cassia auriculata and carbamazepine on (a) blood levels of the prescription drug and (b) changes in toxicity (as assessed by changes in hematological parameters, liver and kidney function, and histology of major body organs) that may occur due to drug interaction. Results demonstrate that in rats receiving the herbal tea and carbamazepine, the blood levels of the prescription drug were significantly enhanced by 47.1% (p <0.04) when compared with the levels in animals receiving only carbamazepine, with no apparent changes in toxicity. Concurrent ingestion of the herbal tea prepared from Cassia auriculata flowers with carbamazepine may therefore influence the bioavailability of the prescribed drug and hence its therapeutic potential.Item Crystallization and preliminary x-ray analysis of shikimate dehydrogenase from Escherichia coli(Wiley-Blackwell, 2000) Maclean, J.; Campbell, S.J.; Pollock, K.; Chackrewarthy, S.; Coggins, J.R.; Lapthorn, A.J.AbstractItem Chemical modifications monitored by electrospray mass-spectrometry: A rapid and simple method for identifying and studying functional residues in protiens and enzymes(Munksgaard, 1998) Krell, T.; Chackrewarthy, S.; Pitt, A.R.; Elwell, A.; Coggins, J.R.A simple method to identify functional amino acids in enzymes is described. This method is based on the mass spectrometric detection of molecular weight changes as the consequence of chemical modification of enzymes with group-specific reagents. Here we report the use of phenylglyoxal, trinitrobenzene sulfonic acid, tetranitromethane and diethylpyrocarbonate to identify functional amino acid residues. Precise information is obtained about the stoichiometry of reaction, and a relationship between the loss of enzyme activity and the amount of chemical modification is easily established. Modification sites are located by proteolytic digestion of the modified enzyme, followed by peptide mapping based on high-pressure liquid chromatography using an electrospray mass spectrometer as an on-line detector. In comparison with more conventional methods, protein modification is monitored directly without the need to use radioactively or spectrally labelled reagents. The methodology is limited only by the stability of the chemically modified species produced. The method has been used to characterise the active sites of several shikimate pathway enzymes, and the results obtained have been confirmed by site-directed mutagenesis and X-ray crystallography.