Browsing by Author "Dias, S."

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Evaluation of the genetic diversity of Domain II of Plasmodium vivax Apical Membrane Antigen 1 (PvAMA-1) and the ensuing strain-specific immune responses in patients from Sri Lanka
(Elsevier, 2011) Dias, S.; Somarathna, M.; Manamperi, A.; Escalante, A.A.; Gunasekera, A.M.; Udagama, P.V.
Antigenic polymorphism displayed by malaria parasites is a skewed schema to escape the host immune system. The prevailing genetic diversity at domain II of the Plasmodium vivax Apical Membrane Antigen-1 (Pvama-1DII) was characterized in 64 single clone P. vivax isolates from Sri Lanka, where unstable malaria prevails with low intensity. In Sri Lanka, the Pvama-1DII gene showed meager meiotic recombination with the enclosure of single nucleotide polymorphisms (SNPs). Eleven amino acid (a.a.) variant positions defined 21 a.a. haplotypes with 9 unique to the island, where the predominant haplotype, H1, was identical to the reference Salvador I strain. A further 376 globally dispersed isolates defined 38 a.a. haplotypes (H22-H59), with 4 and 26 haplotypes exclusive to India and Thailand, respectively. The phylogenetic tree revealed no clustering, where most isolates had a very recent common origin. The polymorphism detected in PvAMA-1DII B and T cell epitopes evidenced an immune evasion mechanism exploited by the parasite. Majority of Sri Lankan patients developed antibody responses to both conformational and linear B cell epitopes. The ensuing strain-specific immunity due to extensive antigenic polymorphism was evaluated by aligning a.a. sequences of PvAMA-1DII with the homologous total (IgM+IgG) antibody responses assayed by in-house established indirect ELISAs against 7 PvAMA-1DII overlapping synthetic peptides, P01-P07. While the antibody responses to P01-P03, P06, P07 harbouring P. vivax clinical isolates with polymorphic a.a. haplotype to Sal I was clearly strain-transcending (cross-reactive), individuals with isolates identical to the Sal I strain observed varying antibody prevalence against the seven PvAMA-1DII Sal-I synthetic peptides, with the highest prevalence detected against P04. Synthetic peptide P04, spanning a.a. positions 302-324 of the PvAMA-1DII of the Sal I strain that included the epitope recognized by the invasion inhibitory 4G2 monoclonal antibody of PfAMA-1, was highly conserved in all 440 local and global P. vivax isolates examined. A functional role for this region is reinforced by the highly immunogenic nature of P04, and could point towards a presumably "protective" anti-P04 antibody response that elicited an isotype switch from IgM to IgG, with increasing exposure to malaria exclusively in endemic residents. Thus the conserved and seemingly "protective" nature of the domain II loop of PvAMA-1 makes it a putative contender to be included in a cocktail vaccine against P. vivax asexual erythrocytic stages in Sri Lanka.
Factor structure of medical students’ attitudes towards psychiatry: findings from a nationally representative sample from Sri Lanka
(Cambridge University Press, 2021) Baminiwatta, A.; Chandradasa, M.; Ediriweera, D.; Dias, S.
AIMS : The aim of this study was to examine the factor structure of attitudes towards psychiatry among medical students by using the ‘Attitude towards psychiatry-30’ (ATP-30) scale, which is one of the most widely used psychometric tools in assessing medical students’ attitudes regarding psychiatry. We also aimed to explore the possible existence of meaningful subscales in the ATP-30 scale. METHOD: Secondary data from a survey of 743 final-year medical students from nine medical schools in Sri Lanka were subjected to factor analysis. Models based on empirical evidence were tested with Confirmatory Factor Analysis (CFA) for model fit using Comparative Fit Index (CFI), Tucker Lewis Index (TLI), root mean square error of approximation (RMSEA) and Chi square. To explore the underlying latent structure of the scale, Exploratory Factor Analysis (EFA) with oblique (i.e. Promax) rotation was employed. Horn's parallel analysis and goodness-of-fit statistics for a series of EFA models tested with different numbers of factors were used in determining the number of factors to retain. Items conceptually external to the emerging factors or with factor loadings less than 0.4 were discarded. Gender invariance of the final model was tested by configural, metric and scalar invariance. Internal consistency of subscales was assessed using McDonald's omega (ω). RESULT: Three models based on literature (one-, five-, and eight- factor) were disproved by CFA. EFA revealed a six-factor solution, encompassing 18 out of the 30 items, to be the most theoretically meaningful factor structure. This six-factor model was affirmed by a CFA (CFI = 0.94, TLI = 0.92, RMSEA = 0.036). These factors were, namely, ‘the image of psychiatrists’, ‘psychiatric patients and mental illness’, ‘efficacy of treatment’, ‘psychiatric teaching’, ‘career choice’, and ‘psychiatry as an evidence-based discipline’. This six-factor solution was invariant across gender. ‘The image of psychiatrists’ appeared to be the most salient factor, and formed the most consistent subscale (ω = 0.71). The internal consistencies of the other subscales were modest (ω = 0.55–0.67). The overall 18-item scale showed good internal consistency (ω = 0.78). CONCLUSION: Our findings provide evidence of a multi-dimensional structure in medical students’ attitudes towards psychiatry, endorsing six meaningful subscales of the ATP-30. Future researchers and educators can utilize these subscales in identifying specific attitudinal domains which are more closely associated with students’ future choice of a career in psychiatry, and also in identifying specific areas where attitudes are more stigmatized, so that appropriate interventions can be incorporated into the undergraduate psychiatric curriculum.
Neuro Lingustic Programming in education : A communication technology for slow learners
(University of Kelaniya, 2013) Dias, S.
This paper is based on a pilot study on developing second language skills of primary school students, based on the theoretical framework of Neuro Linguistic Programming (NLP) in education. It hopes to help struggling slow learners who need a student centred approach to make them fit into the mainstream classroom (Blackerby, 1996). NLP was introduced by Bandler and Grinder as an ‘ art of communication excellence’ and `the study of the structure of subjective experience' (McWhirter, 1992). NLP could be regarded both as a technology for communication and personal development, and a methodology or modelling process (Cameron-Bandler et al 1985; Dilts 1998a; Jacobson 1994). The research problem focusses on the challenges faced by teachers on how to respond to individual needs of children with disabilities and special learning needs in primary classrooms. The research question is could NLP in education help slow learners in the primary classes improve 2nd language skills? Quantitative and qualitative data were obtained through exam results, attendance, teacher/ researcher observation and student feedback. Out of the identified 24 slow learners (n=24), 50% were the experimental group and 50%, the control group. 58% of the experimental group had an average improvement of 09 marks. 42% had an average decrease of 08 marks. Attendance of 75% students was over 80%. Of the students 100% indicated enthusiasm and interest. The teachers who were interviewed reported improved attitudes of students. Of the control group, 58% had an average improvement of 13 marks. 42% had an average decrease of 07 marks.
Revisiting the ATP 30: The factor structure of a scale measuring medical students' attitudes towards Psychiatry
(Springer, 2021) Baminiwatta, A.; Chandradasa, M.; Dias, S.; Ediriweera, D.
OBJECTIVE: Among the scales developed for assessing medical students' attitudes regarding psychiatry, "attitude towards psychiatry-30" (ATP-30) is probably the most widely used. Although this scale was originally deemed to form a unitary dimension without any meaningful subscales, the authors sought to re-examine its factor structure and the viability of subscales. METHOD: Secondary data from a survey of 743 final-year medical students from nine medical schools in Sri Lanka were analyzed using exploratory factor analysis (EFA) with promax rotation and confirmatory factor analysis (CFA), to assess the underlying factor structure of ATP-30. Parallel analysis was used in determining the number of factors to retain. Items conceptually external to the emerging factors were discarded. RESULTS: Three models based on literature (one-, five-, and eight-factor) were disproved by CFA. A six-factor solution encompassing 18 items was supported by EFA and CFA and was gender-invariant. These factors were, namely, the image of psychiatrists, psychiatric patients and mental illness, the efficacy of treatment, psychiatric teaching, career choice, and psychiatry as an evidence-based discipline. While "the image of psychiatrists" formed the most consistent subscale (ω = 0.71), the internal consistencies of the other subscales were modest (ω = 0.55-0.67). The overall 18-item scale showed good internal consistency (ω = 0.78). CONCLUSION: The findings provide evidence of a multi-dimensional structure in medical students' attitudes towards psychiatry, endorsing six meaningful subscales of the ATP-30. Future researchers and educators can utilize these subscales in identifying specific areas where students' attitudes are more stigmatized, to be intervened during undergraduate training. KEYWORDS: ATP-30; Medical students; Psychiatry; Undergraduate education.
Supporting the Emotionally Challenged Undergraduate Using Neuro- Linguistic Strategies: A Qualitative Narrative Approach
(University of Kelaniya, 2015) Dias, S.
Using Narrative constructsthis qualitativeresearch provides an insight into emotional and mental challenges encountered by severalstudents of the English Language Teaching Unit,University of Colombo.Introduction of Neuro Linguistic Programming (NLP) strategies to help these students overcome stressful situationsis discussed through two case studies. NLP is an art and science of personal experience where its patterns, skills and techniques are being used in counselling, education and business for effective communication, personal development and accelerated learning. Research questions are whether students had the opportunity to obtain support for emotional challenges faced, and whether the approach adopted by the researcher had been successful. Opinions of twelve lecturers of the ELTU and two permanent student counsellors were obtained through semi-structured interviews.Two case studies out of eight, conducted by the researcher are described with the ‘Narrative Theory’ which contains specific tools and terms used in qualitative texts that incudes elements of story, character, focalization and plot. Data obtained through observation, journal entries of participant interactive sessions, semi-structured interviews with lecturers and colleagues of relevant students and the mother of one participant was coded and analysed. Two permanent student counsellors mentioned that from approximately 50 students, who came for counselling in 2013, 90% were due to academic related stress, 10% to relationship problems with partners or peersandeconomic problems.Outof thelecturers interviewed, 96% mentioned that each had counselled at least two students during the academic year. One lecturer had 10 students of whom some were referred through the Student Counselling Centre. Of these, 98% of the problemswere academically related. Economic, relationship and personalloss accounted for 02%, and one student had mentioned guiltfeelings due to a sexual problem.The researcher concludes that it could be possible to use NLP techniques to build rapport between teachers and students to gain confidence of the students, and together with NLP stress relieving strategies, help students face crisis situations successfully.