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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Diagnosing human cutaneous leishmaniasis using fluorescence in situ hybridization(Taylor & Francis Publishing, 2021) Kaluarachchi, T.J.; Wickremasinghe, R.; Weerasekera, M.; Yasawardene, S.; McBain, A.J.; Yapa, B.; de Silva, H.; Menike, C.; Jayathilake, S.; Munasinghe, A.; Wickremasinghe, R.; Ranasinghe, S.ABSTRACT: Cutaneous leishmaniasis (CL) is endemic in Sri Lanka. Giemsa-stained slit-skin-smears (SSS-Giemsa) and histology are routinely used in diagnosis with a sensitivity of 40-70%. PCR currently has limited accessibility. Therefore, we assessed the sensitivity and specificity of a previously described fluorescence in situ hybridization assay, on skin smears and biopsy samples to overcome the limitations encountered with routine diagnostic methods.Samples from a total of 123 suspected CL patients were collected and subjected to SSS-Giemsa, fluorescence in situ hybridization (FISH) on slit skin smears (SSS-FISH), formalin-fixed-paraffin-embedded-tissues stained with Hematoxylin & Eosin staining (FFPE-H&E) and FISH on formalin-fixed-paraffin-embedded-tissues (FFPE-FISH). Negative controls of 61 patient samples were collected from a CL non-endemic area and subjected to the same procedures. The gold standard PCR was used as a comparator. For FISH, two previously described cyanine 3 tagged Leihsmania genus-specific probes were used.Compared to PCR, SSS-Giemsa, SSS-FISH, FFPE-H&E, and FFPE-FISH had sensitivities of 76.5%, 79.1%, 50.4% and 80.9%, respectively. Routine diagnostic tests (SSS-Giemsa and FFPE-H&E) had a specificity of 100%. SSS-FISH and FFPE-FISH had specificities of 96.7% and 93.4%, respectively. FFPE-FISH had a statistically significant higher diagnostic performance than FFPE-H&E (p < 0.001). The relative performance of SSS-Giemsa, SSS-FISH and FFPE-FISH was similar (p > 0.05 for all comparisons).We conclude that FFPE-FISH is a more accurate diagnostic tool than FFPE-H&E. SSS-FISH did not have an additional advantage over SSS-Giemsa in diagnosis. However, SSS-FISH could be recommended as a minimally invasive method in studies assessing wound healing where immunological probes are used. KEYWORDS: Cutaneous leishmaniasis; Sri Lanka; fluorescence in situ hybridization.Item Diagnosing Cutaneous leishmaniasis using Fluorescence in Situ Hybridization: the Sri Lankan Perspective(Taylor & Francis, 2019) Kaluarachchi, T.D.J.; Weerasekera, M. M.; McBain, A. J.; Ranasinghe, S.; Wickremasinghe, R.; Yasawardene, S.; Jayanetti, N.; Wickremasinghe, R.Cutaneous leishmaniasis (CL) caused by Leishmania donovani MON-37 is becoming a major public health problem in Sri Lanka, with 100 new cases per month being reported in endemic regions. Diagnosis of CL is challenging for several reasons. Due to relative specificity and rapidity we propose Fluorescence in Situ Hybridization as a diagnostic tool for CL. The objective was to evaluate the potential of Fluorescence in Situ Hybridization as a diagnostic method for Cutaneous leishmaniasis in Sri Lanka. Literature on current laboratory tests used to diagnose Cutaneous leishmaniasis in Sri Lanka and globally was reviewed. Sri Lankan data were reviewed systematically following the PRISMA guidelines. A narrative of the results is presented. There is currently no gold standard diagnostic method for Cutaneous leishmaniasis. Fluorescence in Situ Hybridization has been previously applied to detect dermal pathologies including those involving infectious agents, and its use to detect the Leishmania parasite in human cutaneous lesions reported in small number of studies, generally with limited numbers of subjects. Advantages of FISH has been specificity, cost and ease-of-use compared to the alternatives. Based on the available literature and our current work, FISH has potential for diagnosing CL and should now be evaluated in larger cohorts in endemic regions. FISH for CL diagnosis could find application in countries such as Sri Lanka, where laboratory facilities may be limited in rural areas where the disease burden is highest.Item Association between road accidents and minimal hepatic encephalopathy in a cohort of Sri Lankan cirrhotic drivers(Wiley Blackwell Scientific Publications, 2014) Subasinghe, S.K.C.E.; Nandamuni, Y.; Ranasinghe, S.; Kodisinghe, K.; Niriella, M.A.; de Silva, A.P.; de Silva, H.J.OBJECTIVE: Minimal hepatic encephalopathy (MHE) has no recognizable clinical symptoms of hepatic encephalopathy (HE) but has mild cognitive and psychomotor deficits which can interfere with executive decision making and psychomotor speed. It affects driving ability and previous studies in Western countries have demonstrated an association between MHE and increased road accidents. Our objective was to investigate this association in a cohort of Sri Lankan cirrhotic drivers. METHODS: A prospective, case controlled study ongoing study has been conducted in the Gastroenterology Clinic, University Medical Unit, North Colombo Teaching Hospital, Ragama, from August 2013. Patients with cirrhosis of any aetiology, without overt HE, who had been driving any vehicle during the past one month were subjected to 5 standard pencil-paper based psychometric tests used to detect MHE. Road accidents were recorded for both cirrhotic drivers with MHE and controls. Accidents were categorized as major when they resulted in hospitalization of the involved person/s, and minor when there were no serious injuries. RESULTS: Among 55 cirrhotic drivers with MHE [males, median age 53 years (range 30-60)], 7 (12.7%) reported any type of accident compared to 6 (10.9%) among 55 controls [males; median age 51 years (range 30-60)]. 2/55 (3.6%) cases and 2/55 (3.6%) controls reported minor accidents. There were no major accidents in either group. CONCLUSION: Preliminary results of this ongoing study do not indicate an increased frequency of road accidents in a cohort of Sri Lankan cirrhotic drivers with MHEItem Cross-sectional study to assess risk factorsfor leishmaniasis in an endemic region in Sri Lanka(American Society of Tropical Medicine and Hygiene, 2013) Ranasinghe, S.; Wickremasinghe, R*.; Munasinghe, A.; Hulangamuwa, S.; Sivanantharajah, S.; Seneviratne, K.; Bandara, S.; Athauda, I.; Navaratne, C.; Silva, O.; Wackwella, H.; Matlashewski, G.; Wickremasinghe, R.Sri Lanka reports significantly more cutaneous leishmaniasis (CL) cases than visceral leishmaniasis (VL) cases, both of which are caused by Leishmania donovani MON-37. A cross-sectional study conducted in an area with a high prevalence of CL prevalent included 954 participants of an estimated population of 61,674 to estimate the number of CL cases, ascertain whether there is a pool of asymptomatic VL cases, and identify risk factors for transmission. A total of 31 cases of CL were identified, of whom 21 were previously diagnosed and 10 were new cases. Using rK39 rapid diagnostic test to detect antibodies against Leishmania spp., we found that only one person was seropositive but did not have clinical symptoms of CL or VL, which indicated low transmission of VL in this area. χ(2) test, independent sample t-test, and multivariate analysis of socio demographic and spatial distribution of environmental risk factors showed that living near paddy fields is associated with increased risk for transmission of CL (P ≤ 0.01).