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This repository contains the published and unpublished research of the Faculty of Medicine by the staff members of the faculty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 Unfolded protein response pathway in leishmaniasis: A review(Wiley, 2023) Edirisinghe, N.M.; Manamperi, N.H.; Wanasinghe, V.S.; Karunaweera, N.Alteration in the physiological state of the endoplasmic reticulum (ER) leads to the specific response known as unfolded protein response (UPR) or ER stress response. The UPR is driven by three sensor proteins, namely: Inositol-Requiring Enzyme 1, Protein Kinase RNA-like ER kinase and Activating Transcription Factor 6 to restore ER homeostasis. Pathogenic infection can initiate UPR activation; some pathogens can subvert the UPR to promote their survival and replication. Many intracellular pathogens, including Leishmania, can interact and hijack ER for their survival and replication, triggering ER stress and subsequently ER stress response. This review aims to provide a comprehensive overview of the ER stress response in infections with the Leishmania species.Item ELISA based evaluation of antibody response to Leishmania in a region endemic for cutaneous leishmaniasis(Oxford, 2022) Piyasiri, S.B.; Samaranayake, T.N.; Silva, H.; Manamperi, N.H.; Karunaweera, N.D.Aims: Leishmaniasis includes several clinical forms. While routine diagnosis of cutaneous leishmaniasis (CL) is by microscopy, an antibody response to CL has been reported in several recent studies. This study evaluated anti-leishmanial IgG antibody responses as a biomarker of active leishmaniasis and a measure of exposure to Leishmania. Methods and results: Sera from 50 untreated CL patients, 140 patients under treatment and 280 healthy individuals residing in endemic regions collected as part of an epidemiological survey, was analysed with an ELISA established in-house using receiver-operator-characteristic (ROC) curve at optimised cut-off value. The assay showed high performance as a diagnostic tool in identifying exposure in endemic individuals (sensitivity: 98%, specificity: 90.3%). All patients showed lower antibody levels over time since onset of lesion/s. Antibody levels were higher (p ˂ 0.01) and persisted for a longer period in untreated patients. In patients under treatment, the level of anti-IgG antibodies was negatively correlated with the total duration the patient had been on treatment. Conclusion: The anti-leishmanial IgG response in L. donovani induced CL is transient and is unlikely to confer protective immunity. Optimised serological assays may be useful in endemic settings for diagnosis and monitoring the treatment response in CL.Item Tissue impression smears as a supplementary diagnostic method for histopathology in cutaneous leishmaniasis in Sri Lanka(American Society of Tropical Medicine and Hygiene, 2018) Manamperi, N.H.; de Silva, M.V.C.; Pathirana, N.; Abeyewickreme, W.; Karunaweera, N.D.Cutaneous leishmaniasis (CL) is diagnosed mainly by light microscopy of smears made using lesion material. Histopathology is usually done in atypical presentations or when lesion smears are negative. Tissue impression smears (TIS) made from skin biopsy specimens were compared with histopathology for the diagnosis of CL. Out of the 111 patients included, 83 (74.8%) were positive by either methods. The TIS was positive in 70.3% whereas histopathology was positive in 56.8% of patients. Tissue impression smears can be used as a supplementary diagnostic test that gives sensitive and rapid results when tissue biopsies are used as the source of lesion material for diagnosis of CL.Item In situ immune response to cutaneous leishmaniasis in Sri Lanka(Sri Lanka Medical Association, 2017) Manamperi, N.H.; Oghumu, S.; Pathirana, N.; de Silva, M.V.C.; Abeyewickreme, W.; Satoskar, A.R.; Karunaweera, N.D.INTRODUCTION & OBJECTIVES: Cutaneous leishmaniasis (CL) in Sri Lanka is caused by Leishmania donovani-MON 37, known to cause visceral leishmaniasis elsewhere. Localized immune response may play a role in disease outcome with T helper (Th) 1 response favouring lesion healing and Th2 response leading to disease progression in animal models. This study describes the localized host immune response to CL in Sri Lanka. METHOD: Skin punch biopsies from 58 patients with parasitologically confirmed CL and 25 healthy controls were quantified for cytokine gene expression of Th1 cytokines interferon (IFN)-γ, interleukin (IL)-12A and tumour necrosis factor (TNF)-α and Th2 cytokines, IL-4 and IL-10 by real-time RT-PCR. Relative copy numbers were calculated using the 2-ΔΔCt method. Non-parametric Mann-Whitney U test and the Spearman’s correlation test were used for statistical analysis. RESULTS: Study group consisted of 37 (63.8%) males and 21 (36.2%) females with a mean age of 35.0 years (SD=12.1, range=18-66), mean lesion duration of 6.75 ±9.1 months (range: 1-48) and a mean size of 176.59±185.76 mm2 (range: 12.6–908.3 mm2). Significant up regulation of IFN-γ (p<0.001) and down regulation of IL-4 (p<0.001) were seen in patients compared to healthy controls. Time taken for lesions to heal correlated significantly with in situ expression of IL-4 (Spearman’s r=0.321, p=0.034). CONCLUSION: Immune response to L. donovani induced CL in Sri Lanka tends to follow the typical Th1/Th2 convention with a Th2 biased milieu favouring poor responsiveness to antimony and delayed lesion healing.Item Randomized placebo-controlled trial of the efficacy of mebendazole polymorphs in the treatment of hookworm infections(Sri Lanka College of Microbiologists, 2013) Gunawardena, N.K.; Kumarendran, B.; Manamperi, N.H.; Senarathna, B.P.; Silva, M.; Pathmeswaran, A.; de Silva, N.R.INTRODUCTION: Mebendazole has three polymorphic forms, identified as A, B and C. Animal studies and one previous study in humans have suggested that unlike polymorph C, polymorph A is ineffective in the treatment of hookworm and whipworm infections. OBJECTIVES: A randomized double-blind, placebo-controlled trial was carried out to compare the efficacy of single dose 500 mg tablets of pure mebendazole polymorph C with those containing a 1:1 mixture of polymorphs Aand C, for the treatment of hookworm infections. . DESIGN, SETTING AND METHODS: All eligible individuals living in 219 households in 8 estate divisions in Ratnapura District known to have a high prevalence of hookworm, were recruited after obtaining written, informed consent. A single faecal sample was obtained and examined the same day, using the Kato-Katz technique for quantification of intestinal nematode infections. Those who were found infected with hook¬worms were randomized to one of three treatment arms and requested to provide a second faecal sample 10-14 days after treatment. This was examined in the same manner as the first. RESULTS: A total of 892 individuals were recruited; 601 provided faecal samples; 214 were found positive for hookworm infection; 70, 74 and 70 individuals were randomized to treatment arms A (mixture of polymorphs A and C), B (pure polymorph C) and C (placebo) respectively. Follow-up faeca! samples were provided by 53,48 and 49 persons respectively in each treatment arm. The cure rates in the three treatment arms were 28.3%, 18.8% and 16.3% respectively; they were not significantly different from one another. Comparison of faecal egg count reductions (FECR) in the 3 treatment arms (86.1%, 84.5% and -6.6% in arms A, B and C respectively) showed that both mebendazole formulations performed significantly better than placebo, but there was no statistically significant difference between FECR with the two drug formulations. CONCLUSIONS: A single SOOmg dose of mebendazole, either as Polymorph C alone, or as a mixture of Polymorphs A and C, has little efficacy in curing hookworm infections. However, both formulations are significantly better than placebo in reducing the intensity of infection, with no statistically significant difference between the two formulations.Item Comparison of laboratory techniques for diagnosis of hookworm infections(Sri Lanka College of Microbiologists, 2011) Manamperi, N.H.; Anjalee, K.G.C.; Gunawardena, N.K.; Sudusinghe, H.; Nilaweera, T.H.W.T.; de Silva, N.R.INTRODUCTION: Hookworm infection may be diagnosed by detection of eggs or culturing of larvae from stools. OBJECTIVE: To compare the efficacy of modified Kato-Katz (K-K) technique, saline smears, Harada-Mori (H-M) and nutrient agar culture plate (NACP) methods in diagnosis of hookworm infections. METHODOLOGY: A total of 324 stool samples, from the plantation sector families in Ratnapura district were examined by modified Kato-Katz technique and saline smears, and cultured by Harada-Mori and on NACP according to standard protocols, at the Faculty of Medicine, Ragama. Harada-Mori and NACP were maintained for 7-10 days and larvae or larval tracts observed by a stereomicroscope. Positivity in any two of the four techniques was considered the gold standard positive. Statistical analysis was done using SPSS version 16. RESULTS: A total of 172 (53.1%) samples were positive by at least one method. The positivity rates with K-K, H-M, NACP and saline smears were 42.3% (137/324), 37.7% (122/324), 23.5% (76/324) and 22.2% (72/324) respectively. The highest sensitivity (89.8%) and lowest specificity (88.3%) was seen in modified K-K, the lowest sensitivity (50.4%) in saline smears and the highest specificity in NACP (98.5%). Detection rates with saline smears, H-M and NACP rose with increasing intensity of infection as determined by K-K technique. Harada-Mori had the highest detection rate (70.7%) in light infections. It also detected 11.8% of K-K negative samples. CONCLUSIONS: The modified K-K technique is a reasonably good diagnostic method for detection of hookworm infections. A combination of methods will increase the diagnostic accuracy in hookworm infections.Item Histopathological spectrum in acute and chronic cutaneous leishmaniasis in Sri Lanka(Sri Lanka College of Microbiologists, 2015) Manamperi, N.H.; de Silva, M.V.C.; Fernando, C.; Pathirana, K.P.N.; Abeyewickreme, W.; Karunaweera, N.D.OBJECTIVES: To describe the histological spectrum of acute and chronic cutaneous leishmaniasis. METHOD: Patients from Sri Lanka army were recruited by active and passive case detection methods and punch biopsies were obtained. Skin biopsies of 35 patients with smear positive for Leishmania amastigotes were processed routinely for histopathology, examined at a conference microscope and classified into 4 groups using modified Ridley criteria for Leishmaniasis as: I - parasitized macrophages with variable lymphocytes and plasma cells; II - parasitized macrophages with lymphocytes, plasma cells and ill formed histiocytic granulomata; III -a mixture of macrophages (with or without parasites), lymphocytes, plasma cells and epithelioid granulomata; IV - epithelioid granulomatous response with a few lymphocytes and plasma cells but no amasigotes. Lesions were categorized as acute (<6 months) or chronic (> 6 months). RESULTS: Study group composed of males with a mean age of 32.6 years (range 22-47) and lesion duration of 5.6 months (range 1-24). Twenty nine (82.9%) were also positive by histopathology. Twenty two (62.9%) were acute and 13 (37.1%) chronic. Group I, II, III and IV patterns were seen in 14 (40%), 12 (34.3%), 5 (14.3%) and 4 (11.4%) respectively and 9 (40.9%), 9 (40.9%), 2 (9.1%) and 2 (9.1 %) of acute lesions and 5 (38.5%), 3 (23.1 %), 3 (23.1 %) and 2 (15.4%) of chronic lesions respectively. CONCLUSION: Histology of cutaneous leishmaniasis shows marked inflammatory cell infiltrate with or without granuloma formation. Majority of patients presenting with either acute or chronic cutaneous leishmaniasis belong to histological groups I or II. ACKNOWLEDGEMENTS: Financial assistance from the University Grants Commission, Sri Lanka (UGC/VC/DRIC/PG/2013/KLN/ 03) and University of Kelaniya (RP/03/04/06/01/2014) are acknowledged. An abstract based on similar work was presented at the 128"1 Anniversary International Medical Congress of the Sri Lanka Medical Association, 5th to 8th July 2015.Item Pathogenesis of Leishmania donovani induced cutaneous leishmaniasis: role of Tumor Necrosis Factor α(Faculty of Medicine, University of Kelaniya, Sri Lanka, 2016) Manamperi, N.H.; Oghumu, S.; Pathirana, K.P.N.; Munidasa, U.A.D.D.; Somaratne, K.K.V.N.; Rathnayake, R.M.D.I.; Thilakaratne, S.M.; de Silva, M.V.C.; Pathmeswaran, A.; Abeyewickreme, W.; Satoskar, A.R.; Karunaweera, N.D.BACKGROUND: Cutaneous leishmaniasis (CL) in Sri Lanka is caused by the usually visceralizing Leishmania donovani. Host immune response plays a key role in the clinical presentation of leishmaniasis. Role of cytokines in pathogenesis of local lesions has not been studied. OBJECTIVE: To describe tissue cytokine expression with lesion progression with time in CL due to Leishmania donovani. METHODS: Skin biopsies from fifty eight patients with parasitologically or histopathologically confirmed CL and 30 healthy controls were analyzed for local tissue expression of Interleukin (IL)-12A, IL-4, IL-10, Interferon-gamma (IFNg) and Tumor Necrosis Factor-alpha (TNF-α). Cytokine mRNA was quantified by real-time RT- PCR using SYBR green. Relative copy numbers were calculated for each gene by 2-ΔΔCt method using β-actin as the reference gene and healthy controls as the calibrator. Spearman correlation was used to determine the correlation between cytokines and duration of active skin lesions. RESULTS: The study group consisted of 37 males (63.8%) and 21 females (36.2%) with a mean age of 35 (SD=12.05) years which ranged between 18-66 years. Mean duration of lesions was 6.8 (SD=9.10) months with a range of 1-48 months. The Spearman correlation coefficient for relative copy numbers and lesion duration was 0.220, 0.077, 0.073, 0.235 and 0.295 for IL-12A, IL-4, IL-10, IFNg and TNF-α respectively. There was a significant positive correlation between expression of TNF-α and lesion duration (p= 0.024). CONCLUSIONS: Localized expression of TNF-α increases with time in CL due to L. donovani in Sri Lanka, which indicates development of a pro-inflammatory immune response at the site of infection as the disease progresses.Item Histopathological spectrum in acute and chronic Cutaneous Leishmaniasis in Sri Lanka(Sri lanka Medical Association, 2015) Manamperi, N.H.; Fernando, C.; Pathirana, K.P.N.; Karunaweera, N.D.; Abeyewickreme, W.; de Silva, M.V.C.INTRODUCTION AND OBJECTIVES: Histological spectrum in cutaneous leishmaniasis (CL) is wide and varied. The objective of this study is to describe the histological spectrum of acute and chronic CL. METHOD: Skin biopsies of 35 patients with smear positive for Leishmania amastigotes were processed routinely for histopathology, examined at a conference microscope and classified into 4 groups using modified Ridley criteria for Leishmaniasis as: I- parasitized macrophages with variable lymphocytes and plasma ceils; 1! - parasitized macrophages with lymphocytes, plasma cells and ill formed histiocytic granulomata; 111 - a mixture of macrophages (with or without parasites), lymphocytes, plasma cells and epithelioid granulomata; IV - epithelioid granulomatous response with a few lymphocytes and plasma cells but no amastigotes. Lesions were categorized as acute (< 6 months) or chronic (> 6 months). RESULTS: Study group composed of all males with a mean age of 32.6 years (range 22 - 47) and lesion duration of 5.6 months (range 1-24). Twenty nine (82.9%) were also positive by histopathology. Twenty two (62.9%) were acute and 13 (37.1%) chronic. Group I, II, Ml and IV patterns were seen in 14 (40%), 12 (34.3%), 5 (14.3%) and 4 (11.4%) respectively and 9 (40.9%), 9 (40.9%), 2 (9.1%) and 2 (9.1%) of acute lesions and 5 (38.5%), 3 (23.1%), 3 (23.1%) and 2 (15.4%) of chronic lesions respectively. CONCLUSION: Histology of CL shows marked inflammatory cell infiltrate with or without granuloma formation. Majority of patients presenting with either acute or chronic CL belong to histological groups I or II.Item Shifting of circulating serotypes in dengue outbreaks during 2009/2010 in Sri lanka(Faculty of Tropical Medicine, Mahidol University, 2010) Manamperi, N.H.; Athapaththu, A.M.M.H.; Premawansa, G.; Wellawaththage, C.; Jayarathna, T. D. S. S.; Abeyewickreme, W.; Hapugoda, M.D.OBJECTIVES: Sri Lanka has experienced explosive outbreaks of dengue infection in 2009 and 2010. It has been identified that DEN- 3 and DEN- 2 were the predominant serotypes with DEN-1 and DEN- 4 circulating at a lower level in previous dengue outbreaks during 2003-2006, Objective of this study was to identify the circulating serotype/s during 2009 - 2010 outbreaks. METHODOLOGY: A prospective study was carried out at North Colombo Teaching Hospital, Sri Lanka during December 2009-August 2010. Clinically suspected dengue patients, with fever less than 5 days were recruited. An interviewer administered questionnaire was filled for each patient, by a Medical Officer. Venous blood samples confirmed for the presence of dengue virus by RT-PCR were typed by Semi-Nested PCR. RESULTS: Out of the 209 patients recruited in the study 80 (38%) were positive for dengue virus by RT-PCR. Of the positives, 43 (54%) were typed and circulation of all 4 serotypes was observed- Of the 43 positives, presence of DEN-1, DEN-2, DEN-3 and DEN-4 serotypes was 34 (79%), 3 (7%), 2 (5%) and 3 (7%) respectively DEN-1 was the predominant serotype in the recent epidemics which was circulating at a low level in previous epidemics. In DEN-1 infected patients, the mean platelet value was 58,588/ rnm3 and the mean PCV value was 41.4%. Associated symptoms such as headache, retro-orbital pain, neck pain and limb pain were present in 94% (32/34), 59% (20/34), 24% (8/34J and 91% (31/34) patients respectively. Bleeding manifestation developed in 47 % (16/34) patients. The mortality rate ranged from 0.7%- 1.0% during the recent outbreaks. Acknowledgement: Financial and technical assistance from the International Centre for Genetic Engineering and Biotechnology (ICGEB CRP/ SRI08-02) and the International Atomic Energy Agency (IAEA SRI 5/042) is gratefully acknowledged.