Conference Papers
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This collection contains abstracts of conference papers, presented at local and international conferences by the staff of the Faculty of Medicine
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Item Oxidative stress and antioxidant deficiency in the β-thalassaemia in Sri Lanka(Sri Lanka Medical Association, 2021) Perera, S.; Allen, A.; Mettananda, S.; Rodrigo, R.; Perera, L.; Darshana, T.; Moggach, F.; Jackson-Crawford, A.; Heirene, L.; Fisher, C.; Olivieri, N.; Rees, D.; Allen, S.; Premawardhena, A.Introduction In the β thalassaemias oxidative stress is potentially high and this could be further exacerbated in the absence of robust antioxidant defences, such as nutritional vitamin C and E deficiencies. We undertook a comprehensive assessment of oxidant, antioxidant and inflammatory status in patients with subtypes of β-thalassaemia to study these factors in detail. Methods Consenting patients attending the thalassaemia centre in Ragama, (between November 2017 and June 2018) were assessed for the following: methaemoglobin, plasma haemoglobin, heme and ferritin as sources of oxidants, plasma haptoglobin, hemopexin and vitamins C and E as markers of antioxidants, plasma interleukin-6 and C-reactive protein for inflammation. Fruit and vegetable intake was determined by dietary recall. Results 162 patients were recruited. (59 HbE β-thalassaemia, 50 β-thalassaemia major, 40 β-thalassaemia intermedia, 13 HbS β-thalassaemia. Median age was 26.0 years (IQR 15.3-38.8), 101 (62.3%) were female. Oxidants were frequently increased and antioxidants depleted with high levels of oxidant damage, hypoxia and inflammation. Abnormalities were most severe in HbE-β thalassaemia and least severe in β thalassaemia intermedia. Oxidative stress was also more severe in splenectomised patients. Plasma vitamin C concentration was below the lower level of quantitation in 86/160 (53.8%) patients and vitamin E in 130/160 (81.3%) patients. Less than 15% of patients ate fresh fruits or raw vegetables frequently. Conclusion Markedly increased oxidative stress and antioxidant deficiency were observed in this study group, especially in those with HbE β-thalassaemia. Vitamin C & E supplementation may have a role in the long-term management of thalassaemia syndromes.Item Identifying haemoglobinopathy traits and iron deficiency in Sri Lanka using the dtchlorophenolindophenol (DCIP) and one- tube osmotic fragility (OF) tests and measurement of red cell zinc protoporphyrin (ZPP)(Sri Lanka Medical Association., 2019) Perera, P. S.; Premawardhena, A.; Mettananda, S.; Rodrigo, R.; Perera, L.; Weatherall, D. J.; Allen, S.; Allen, A.INTRODUCTION & OBJECTIVES: Effective, low-cost, point-of-care tests are needed for haemoglobinopathy traits and iron deficiency throughout Southeast Asia. The objective of this study is to evaluate a combination of simple, low cost, easy-to-interpret and rapid tests as a "one-stop" screening procedure for identifying carriers of haemoglobin variants and iron deficiency in Sri Lanka. METHODS: Between November 2017 and May 2018, the KKU-OF and KKU modified DCIP tests (KKU, Thailand) were compared with High Performance Liquid Chromatography (HPLC) in a cross-sectional survey of 1324/1332 (99.4%) children attending secondary schools in Gampaha district, Sri Lanka. Iron deficiency was indicated in children with a raised red cell ZPP (Helena Biosciences), and confirmed by measurement of low serum ferritin and normal C- reactive protein (CRP). RESULTS: Median age was 17 years (IQR 16-18), all were Sinhalese and 814/1324 (61.5%) were female. HPLC identified 26 students with β-thalassaemia trait and 3 with HbE trait. The KKU-OF test correctly identified all 26 students with β-thalassaemia trait (sensitivity=100%) but was also positive in 288 samples with a normal HPLC result (specificity= 1007/1295; 85.5%). The KKU-DCIP test was positive only in the 3 students with HbE (100% sensitive and 100% specific). Iron deficiency was present in 148/1318 (11.2%) students. CONCLUSION: This one-stop approach may be an effective and affordable procedure in screening for haemoglobinopathy traits and identifying iron deficiency. We are investigating the causes of the false positive OF test results and planning large scale studies to assess cost-effectiveness.Item 20 year follow up and survival analysis in a cohort of patients with Haemoglobin E beta Thalassaemia.(Sri Lanka Medical Association., 2019) Olivieri, N.F.; Premawardhena, A.P.; Amir-Arsalan, S.; Ediriweera, D.; Mettananda, S.; Bandara, W.D.; Arambepola, M.; de Silva, S.; Refai, M.A.C.M.; Allen, A.INTRODUCTION & OBJECTIVES: Haemoglobin E beta thalassaemia (EBT) is the commonest beta thalassaemia syndrome in the world and is extremely phenotypically variable. Unlike for transfusion dependent thalassaemia (TDT) there are no clear guidelines for the management of this disease. We have followed up a cohort of 109 patients with EBT for 20 years. Objective of the study was to study the 20-year survival and factors that affect survival. METHODS: Study was conducted at Kurunegala Thalassaemia centre. Transfusions were stopped in 1997 in all 109 patients. Since then they were assessed every three months by the clinical team for the next 20 years. Relevant haematological, biochemical, radiological assessments were done periodically. RESULTS: 32 (30%) of patients were dead at 20 years. Kaplan Meir survival curve identified the median survival to be 51 years. Splenectomy had been done in 73/109 (67%) patients. Splenectomy allowed 66% to be off transfusions even 9.7± 1.3 years post- surgery. However, 33% had to return to transfusions. The commonest cause of death in the cohort was infections (34.3%). Most (72%) infective deaths happened in those who were splenectomised. Transfusions needed to be restarted in 60%, of whom 33% went back to (>8 per year) regular transfusions at a mean 8.4 ±0.8 years after stopping transfusions. CONCLUSION: In this first ever long term follow up study of EBT, significantly shortened survival is observed. Though splenectomy allows prolonged transfusion free phases in many it increases risk of infective deaths. Overall the disease is far less benign than previously thought with a high prevalence of morbidity and mortality.Item Techniques for primary screening for haemoglobinpathies in Sri Lanka: a comparison of single tube osmotic fragility (STOP) and dye test {DCIP) vs full blood count (FBC)(Sri Lanka Medical Association, 2007) Premawardhena, A.P.; Williams, S.; Idirisinghe, A.; Allen, A.; Olivieri, N.F.; Weatherall, D.J.INTRODUCTION: Techniques best suited for haemoglobinopathy screening of the Sri Lankan population need to be determined. Full blood count is used to detect p thalassaemia trait but is affected by iron deficiency. Its ability to detect haemoglobin (Hb) E is less certain. Alternative tests for screening include single tube osmotic fragility (STOP) test (for [5 thalassaemia) and a dye test (DCIP) for HbE. However there is no consensus regarding their usage in population surveys. OBJECTIVES: To decide the validity of STOP and DCIP test as screening tests for haemoglobin disorders in Sri Lanka. DESIGN, SETTING AND METHODS: Blood samples of volunteers attending an educational campaign held at the Faculty of Medicine, Ragama were tested using STOP, DCIP and FBC, and the results compared with the "gold standard" HPLC (high performance liquid chromatography) Results: 1062 individuals participated. HPLC identified 27 p traits and 3 HbE carriers. A total of 508 subjects had either MCV < 80 or MCH <27 on FBC, which included 26 of the p traits and all with HbE. The rest were presumably iron deficient. Only 56 subjects had a positive STOF test including 26 with p trait. 34 had a positive DCIP test including all three HbE carriers. One person with HbA2 of 3.5% had a normal MCV, MCH, negative STOF and negative DCIP. STOF test had a sensitivity and specificity of 96% and 97% for p trait. The DCIP had a sensitivity and specificity of 100% and for the detection of Hb E. CONCLUSIONS: Both STOF and DCIP are excellent tests for primary screening. The STOF is a superior test for screening thalassaemias than FBC in populations with high prevalence of iron deficiency.