Medicine
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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty
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Item Detection of human strongyloidiasis among patients with a high risk of complications attending selected tertiary care hospitals in Colombo, Sri Lanka using molecular and serological diagnostic tools(BioMed Central, 2024-10) Weerasekera, C.J.; Gunathilaka, N.; Menike, C.; Anpahalan, P.; Perera, N.; De Silva, N.R.; Wickremasinghe, R.BACKGROUND Strongyloidiasis a neglected tropical disease is known to cause severe disease among immunosuppressed and has not been studied extensively in Sri Lanka. Parasitological diagnostic approaches based on faecal microscopy and culture often fail to detect low-intensity infections. This study investigates the presence of strongyloidiasis among selected immunocompromised individuals using parasitological, molecular and serological techniques.METHODS Adult patients with immunocompromising conditions admitted to three tertiary care hospitals in Sri Lanka were recruited. A faecal sample and 2 ml of venous blood were collected. The faecal samples were subjected to direct faecal smear and cultures (agar plate, charcoal and Harada-Mori) and polymerase chain reaction (PCR) using species specific primers designed for Strongyloides stercoralis. The presence of Strongyloides IgG antibodies was tested in the collected serum samples using DRG Strongyloides IgG enzyme-linked immunosorbent assay (ELISA) kits. The PCR products of the positive samples were sequenced using Sanger sequencing method.RESULTS A total of 260 patients were recruited to this study, out of which 160 provided faecal samples and 122 provided blood samples. Out of the 160 faecal samples, none were positive for strongyloidiasis by direct smear, charcoal and Harada-Mori cultures. Only one sample (0.6%) was positive by agar plate culture. Out of the 123 samples subjected to PCR, 14 (11.4%), including the culture positive patient, were positive for S. stercoralis. Sequencing results of the PCR products indicated 100% similarity to S. stercoralis. Out of the 122 serum samples subjected to ELISA, 20 (16.4%), including the culture positive patient, were positive for Strongyloides IgG antibodies. However, sociodemographic, exposure factors, clinical features were not significantly associated with the presence of strongyloidiasis infection.CONCLUSIONS Strongyloidiasis is present among the immunocompromised population in Sri Lanka, even in the absence of a significant relationship with associated factors. It is advisable to screen such patients with highly sensitive tests such as PCR for early diagnosis and treatment.Item Molecular diagnosis of Williams Buren syndrome in a cohort of Sri Lankan patients(Sri Lanka Medical Association, 2012) Ranaweera, D.M.; de Silva, D.; Samarasinghe, D.; Perera, S.; Rajapaksha, N.; Chandrasekharan, N.V.INTRODUCTION: Williams Bueren Syndrome (WBS) is a common genetic cause of congenital heart defects associated with developmental delay, hypercalcaemia and characteristic facial dysmorphism. It is caused by a 1.5 to 1.8 Mb deletion of chromosome 7qll.23 involving the loss of around 23 genes including the elastin (ELN) gene. This study reports the development of a semi quantitative PCR method to diagnose WBS. AIMS: To establish a molecular diagnostic test for WBS and determine the frequency of ELN deletions among clinically suspected cases. METHODS: Sixteen suspected WBS cases identified by two paediatric cardiologists were recruited following ethical clearance and informed consent. DNA was extracted and dosage analysis was carried out using semi-quantitative PCR. In a multiplex PCR reaction normal (N), positive control (with a confirmed deletion) and patients' (PJ DNA was amplified using 2 primer pairs which amplified regions within the ELN gene and the CFTR gene on chromosome 7 but outside the deleted region. Following agarose gel electrophoresis, the amplified products were quantified. A ratio of P:N of 0.5 indicated the presence of a deletion while a ratio of 1 indicated the absence of a deletion. RESULTS: Among sixteen suspected cases, 12 (75%) had an ELN gene deletion while 4 cases did not. CONCLUSIONS: This semi-quantitative PCR method was able to distinguish ELN deleted cases from the non deleted ones. The preliminary data supports this as a useful diagnostic test for WBS but validation is required before its clinical use.