Browsing by Author "Ranaweera, A."

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Clinically helpful rickettsial disease diagnostic IgG titers in relation to duration of illness in an endemic setting in Sri Lanka
(Biomed Central, 2012) Premaratna, R.; Weerasinghe, S.; Ranaweera, A.; Chandrasena, T.G.A.N.; Bandara, N.W.; Dasch, G.A.; de Silva, H.J.
BACKGROUND: Although an initial IFA-IgG titer greater or equal to 1/64 or 1/128 is considered positive in presumptive diagnosis, in clinical practice in an endemic setting for rickettsioses in Sri Lanka, some patients with IFA-IgG titer of 1/128 for either spotted fever group (SFG) or scrub typhus (ST) did not respond to treatment. FINDINGS: To determine a clinically helpful diagnostic algorithm, IFA-IgG results of serologically confirmed treatment responders were analyzed in relation to duration of illness at sampling. Of 146 suspected SFG, 3 responders of 25 patients had titers ≤1/128 with < 7 days of illness while all 9 with titers ≥1/256 responded (false negative with 1/256 cutoff was 12%, false positive was 0%). For illness > 7 days, the false negative and positive rates were 4.3% (3/59) and 11.3% (6/53). Of 115 suspected ST, false negative and positive rates with ≥1/256 cutoff at <7 days of illness were 14.2% (2/14) and 0% (0/8) respectively while > 7 days, false negative and positive rates were 2% (1/51) and 0% (0/42). CONCLUSIONS: For clinical decision making, duration of illness at sampling is important in interpreting serology results in an endemic setting. If sample is obtained ≤7 day of illness, an IgG titer of ≤1/128 requires a follow up sample in the diagnosis and > 7 days of illness, a single ≥1/256 titer is diagnostic for all ST and 90% of SFG.
Incidence of inflammatory bowel disease in Gampaha district: details of the Sri Lankan component of the Asia-Pacific Crohn's and Colitis Epidemiology Study
(Sri Lanka Medical Association, 2014) Kasturiratne, A.; Mufeena, M.N.; Mettananda, K.C.D.; Fernandopulle, N.; Rajindrajith, S.; Waraketiya, P.R.; Weerasinghe, S.K.; Ranaweera, A.; Hewavisenthi, S.J.de S.; de Silva, A.P.; de Silva, H.J.
The aim of this report is to provide details of the methodology and results of the Sri Lankan component of the Asia-Pacific Crohn's and Colitis. Epidemiology Study. Fourteen state and private hospitals with specialist services in the Gampaha and Colombo districts were kept under surveillance over a 12 month period to recruit patients with newly diagnosed Inflammatory Bowel Disease (IBD) who were permanent residents of the Gampaha district. Thirty five cases (ulcerative colitis-21, Crohn's disease-13, IBD-undetermined-1) were detected, giving a crude annual IBD incidence of 1.59 per 100,000 population.
The Long-term outcomes of a cohort of Sri Lankan patients with ulcerative colitis: a retrospective study at two national referral centers and review of literature
(Dove Medical Press, 2013) Senanayake, S.M.; Fernandopulle, A.N.; Niriella, M.A.; Wijesinghe, N.T.; Ranaweera, A.; Mufeena, M.N.; Pathmeswaran, A.; Navarathne, N.M.; de Silva, A.P.; de Silva, H.J.
BACKGROUND: Inflammatory bowel disease, especially ulcerative colitis, is increasing in many "non-Western" countries, including Sri Lanka. The aim was to evaluate long-term outcomes of ulcerative colitis in a Sri Lankan population. METHODS: A retrospective cohort study was conducted at the gastroenterology clinics of the Colombo North Teaching Hospital, Ragama and the National Hospital of Sri Lanka, Colombo; the two major referral centers for ulcerative colitis. All cases had histological confirmation of ulcerative colitis. Three outcomes: colectomy, development of colorectal carcinoma, and death were assessed. Patients not attending the clinic during the previous 4 weeks, or their families, were contacted to obtain clinical details and survival status. In those who had died, the cause of death was confirmed from clinical records and death certificates. RESULTS: Details of 348/425 (81.9%) patients with ulcerative colitis (mean age 45.6 [standard deviation {SD} 14.3] years, male/female ratio = 1.00:1.03) were available. The mean follow-up was 6.8 (SD 6.5) years. The cumulative colectomy rates at 1, 5, 10, and 15 years were 1.5%, 4.0%, 5.5%, and 9.3% respectively. The cumulative probability of colorectal cancer in this cohort after 10 and 15 years was 0.47% and 2.36% respectively. The cumulative survival rate after 1, 5, 10, and 15 years was 99.7%, 98.9%, 98.1%, and 94.5% respectively. Patients with pancolitis were more likely to have disease-related death (P = 0.05). Multivariate analysis (Cox proportional hazards model) showed that an older age at diagnosis was associated with long-term mortality (hazard ratio, 1.11; P = 0.001). CONCLUSION: In this cohort, colectomy, colorectal carcinoma, and death rates were low, suggesting a relatively benign disease course for ulcerative colitis.
Recurrent urinary tract infections in females - a prospective analysis
(Sri Lanka Medical Association, 2012) Mettananda, K.C.D.; Ranaweera, A.; Mettananda, D.S.G.
INTRODUCTION: Urinary tract infection (UTI) is the commonest infection in women worldwide. Patients with co-morbidities or predisposing factors are at risk of developing recurrent UTI. They require hospitalisation, since causative organisms acquire resistance to first-line antibiotics and intravenous second-line antibiotics are indicated for complete eradication. Consequently, there is disturbance to lifestyle and loss of productivity for the patient. AIMS: To describe clinical profile and risk factors of female patients with recurrent UTI. Methods: All females admitted to the University Medical Unit at Teaching Hospital, Ragama from April 2011- March 2012, with >2 UTI occurring within the previous 12-months, were recruited. Data was collected using an interviewer-administered questionnaire. Results: 22 patients [mean age 48.8 years (SD+16.8, range 14-73]] fulfilled inclusion criteria. 16 (73%) were post-menopausal.13(59%) had diabetes, with poor control in 12. Other risk factors were constipation (27%), cystocele (14%), urinary calculi (9%) and hydronephrosis (9%). Urine culture was performed before antibiotics in 17(77%). 88% pre-treatment cultures were positive. 11(50%) had pyelonephritis during the current admission. 85% of diabetics had positive cultures compared to non-diabetics (77%) (p=0.55). Escherichia coll was the commonest pathogen (in 67.5%). Pyelonephritis was commoner among diabetics (61%) than non-diabetics (33%) 0=0.193). CONCLUSIONS: Post-menopausal women with poorly controlled diabetes are likely to have pyelonephritis when they develop recurrent UTI. Better glycaemic control, avoiding constipation and early treatment of structural abnormalities will reduce recurrent UTI in the at-risk population.
Recurrent urinary tract infections in females - a prospective analysis
(Sri Lanka Medical Association, 2012) Mettananda, K.C.D.; Ranaweera, A.; Mettananda, D.S.G.
INTRODUCTION: Urinary tract infection (UTI) is the commonest infection in women worldwide. Patients with co-morbidities or predisposing factors are at risk of developing recurrent UTI. They require hospitalisation, since causative organisms acquire resistance to first-line antibiotics and intravenous second-line antibiotics are indicated for complete eradication. Consequently, there is disturbance to lifestyle and loss of productivity for the patient. AIMS: To describe clinical profile and risk factors of female patients with recurrent UTI. Methods: All females admitted to the University Medical Unit at Teaching Hospital, Ragama from April 2011- March 2012, with >2 UTI occurring within the previous 12-months, were recruited. Data was collected using an interviewer-administered questionnaire. Results: 22 patients [mean age 48.8 years (SD+16.8, range 14-73]] fulfilled inclusion criteria. 16 (73%) were post-menopausal.13(59%) had diabetes, with poor control in 12. Other risk factors were constipation (27%), cystocele (14%), urinary calculi (9%) and hydronephrosis (9%). Urine culture was performed before antibiotics in 17(77%). 88% pre-treatment cultures were positive. 11(50%) had pyelonephritis during the current admission. 85% of diabetics had positive cultures compared to non-diabetics (77%) (p=0.55). Escherichia coll was the commonest pathogen (in 67.5%). Pyelonephritis was commoner among diabetics (61%) than non-diabetics (33%) 0=0.193). CONCLUSIONS: Post-menopausal women with poorly controlled diabetes are likely to have pyelonephritis when they develop recurrent UTI. Better glycaemic control, avoiding constipation and early treatment of structural abnormalities will reduce recurrent UTI in the at-risk population.
A Study on the Usage of Library Versus Internet as Sources of Information by Undergraduate Students of University Kelaniya: with Special Reference to Faculty of Humanities, Social Sciences, Science and Commerce & Management Studies
(Faculty of Graduate Studies, University of Kelaniya, Sri Lanka, 2016) Ranaweera, A.; Rubashinghe, S.; Priyangika, S.; Bodhinayaka, D.
The library of the University of Kelaniya plays a significant role to support learning, teaching and research activities of the academic community by providing print and e-resources. As at July, 2016 the library of the University of Kelaniya comprised of 250301 printed books, 2157 CD-ROMs, 1203 theses and 800 non-book materials. In addition, the library has subscribed to 60 local journals and access to provide over 12,500 full text academic journals and 100,000 ebooks. At present library usage patterns and information seeking behaviors of undergraduates have been change due to the introduction of Wifi facilities for students and changes of the courses modules, curriculums and teaching methods of the university education system. Both academic staff and students have adopted and continue to use the online information retrieval for their academic and research work. This study aims to compare the usage of library and the Internet to find information sources in the faculties of Humanities, Social Sciences, Science and Commerce & Management in the University of Kelaniya. This research attempts to determine the factors of enthusiasm and the disinterest of students on using library and Internet. All the undergraduate students in the University which is 8440 (as at August 2016) were taken as the study population and 368 students were selected as the sample by using Krejcie and Morgan method. The quantitative data were analyzed by using Descriptive Statistical Method. Findings, of the study indicated that undergraduate students of all the selected faculties use both the library and the Internet to fulfill their information needs. The students of faculty of Science and faculty of Commerce & Management selected Internet as the most preferred source of information.
Supercapacitor Assisted Hybrid PV System for Efficient Solar Energy Harnessing
(Electronics 2021, 2021) Piyumal, K.; Ranaweera, A.; Kalingamudali, S.; Kularatna, N.
In photovoltaic (PV) systems, maximum power point (MPP) is tracked by matching the load impedance to the internal impedance of the PV array by adjusting the duty cycle of the associated DC-DC converter. Scientists are trying to improve the efficiency of these converters by improving the performance of the power stage, while limited attention is given to finding alternative methods. This article describes a novel supercapacitor (SC) assisted technique to enhance the efficiency of a PV system without modifying the power stage of the charge controller. The proposed system is an SC—battery hybrid PV system where an SC bank is coupled in series with a PV array to enhance the overall system efficiency. Developed prototype of the proposed system with SC assisted loss circumvention embedded with a DC microgrid application detailed in the article showed that the average efficiency of the PV system is increased by 8%. This article further describes the theoretical and experimental investigation of the impedance matching technique for the proposed PV system, explaining how to adapt typical impedance matching for maximum power transfer.