Antigens of diagnostic and prophylactic importance inEntamoeba histolytica

Summary  Amoebiasis, caused by an enteric protozoanEntamoeba histolytica, is one of the major parasitic diseases of mankind. Current estimate suggests that the parasite infects about 10% of the world population at any given time. There is an urgent need to characterize the antigenic molecules ofE. histolytica, and find out antigens which have both immunodiagnostic and prophylactic potential against amoebiasis. The results of somatic antigen analysis, using sera from immune or infected individuals, indicated that the wholeE. histolytica trophozoites, are highly complex and heterogeneous in nature and both immunodiagnostic and immuno prophylaxis activity remain mainly in a surface associated 29 kDa glycoprotein ofE. histolytica. Future studies at molecular level particularly, genes responsible for expression of this protein, their homology with other proteins and structure analysis will give better understanding about this polypeptide. Studies on excretory secretory antigens, clearly demonstrated thatE. histolytica like many organisms, also liberates certain antigenic moieties into the culture medium during in vitro cultivation and this antigen has similar diagnostic values like the conventional somatic antigens. It is important that the ESA should be prepared from the supernatant after collecting the cell and use for immunodiagnosis of amoebiasis. This is an additional source of antigen which will help in carrying out more tests using the same reagents. Further studies are needed to clarify the location of these molecules on the parasite, along with detailed biochemical and immunological characterization and their relation with the pathogenesis. This was presented at the symposium on “Recent Trends in Tropical Disease Research”, held at Sevagram on 5-6 September, 1997.     

Socio-Economic Profile of Shopkeepers in Embedded Markets: Social and Cultural Perspectives From a Hundred Years of Bengali Literary Works

Retailing, in the context of developing economies, has been claimed to be a social practice. A review of fictional literature from the ethno-linguistic region of Bengal may enhance our understanding of the social and cultural history of independent retailing. The evidence from social sciences shows that most retail markets in the economically less developed countries function in similar ways. Such a similarity in social structures may be explained using the concept of embeddedness. This article identifies the history of socio-economic roles of rural unorganised retailers in the embedded markets of developing economies through the discourse analysis of Bengali fictional literature.     

“Is caste race?” Discourses of Racial Indianization

This paper investigates how the official discourse of race and caste are constructed in response to the Dalits’ claims that casteism is racism and caste should be included in the World Conference against Racism, Racial Discrimination, and Xenophobia (WCAR held in Durban in 2001). The research question driving this project probes into discursive strategies and logics, which deny any association of caste with race in the Indian context and the significance of race denial. The paper also questions whether the denial of association of race and caste is indicative of racial Indianization. I argue that in India, race lives through the category of caste as a form of racial Indianization.     

The effects of Common Knowledge Construction Model sequence of lessons on science achievement and relational conceptual change

The purpose of this study was to investigate the effects of the Common Knowledge Construction Model (CKCM) lesson sequence, an intervention based both in conceptual change theory and in Phenomenography, a subset of conceptual change theory. A mixed approach was used to investigate whether this model had a significant effect on 7th grade students' science achievement and conceptual change. The Excretion Unit Achievement Test (EUAT) indicated that students (N = 33) in the experimental group achieved significantly higher scores (p < 0.001) than students in the control group (N = 35) taught by traditional teaching methods. Qualitative analysis of students' pre‐ and post‐teaching conceptions of excretion revealed (1) the addition and deletion of ideas from pre‐ to post‐teaching; (2) the change in the number of students within categories of ideas; (3) the replacement of everyday language with scientific labels; and (4) the difference in the complexity of students' responses from pre‐ to post‐teaching. These findings contribute to the literature on teaching that incorporates students' conceptions and conceptual change. © 2009 Wiley Periodicals, Inc. J Res Sci Teach 47: 25–46, 2010     

Rethinking e-learning support strategies

This paper discusses an e-learning support team model developed as part of a new e-learning strategy within a tertiary education polytechnic. Based upon a community of practice model, the e-Team supports the establishment of e-learning and m-learning (mobile learning) throughout the institution as a catalyst for the adoption of social constructivist pedagogy. The paper reviews and reflects upon the impact of strategies for creating and supporting communities of practice across the institution along with the ways this model is achieving the breaking down of the barriers to ‘e’ and ‘m’ learning adoption among lecturers. This model helped to move lecturers from non-engagement to legitimate peripheral participation and onto full participation within the institution’s e-learning community, and ultimately enabling social constructivist learning environments for students. This model based on a community of practice framework for e-learning support is potentially transferable to other educational contexts.     

Diagnostic Role of Tumour Markers CEA, CA15-3, CA19-9 and CA125 in Lung Cancer

The aim of this study was to assess the diagnostic yield of the tumour markers carcinoembryonic antigen, carbohydrate antigen 15-3, carbohydrate antigen 19-9 and carbohydrate antigen 125, in serum and bronchoalveolar lavage fluid in a group of patients with bronchogenic carcinoma. Serum and bronchoalveolar lavage fluid samples were collected in a group of 90 patients with benign or malignant pulmonary diseases. After appropriate processing, tumour markers were determined by enzyme immunoassay. The diagnostic yields (sensitivity, specificity and predictive values) in each environment (serum and bronchoalveolar lavage fluid) were obtained by using "Receivers operating characteristic" curve. Determined individually, carcinoembryonic antigen, carbohydrate antigen 19-9 and carbohydrate antigen 125, showed the greatest diagnostic accuracy in bronchoalveolar lavage fluid. Carbohydrate antigen 15-3 did so in serum. Carcinoembryonic antigen was the most relevant marker in bronchoalveolar lavage fluid. For the factors evaluated in this study, determination of carcinoembryonic antigen, carbohydrate antigen 19-9 and carbohydrate antigen 125 in bronchoalveolar lavage fluid were clinically more useful markers in comparison with serum, although the latter may also be helpful in certain situations. Although there is no specific tumour marker for lung cancer, the combination of several can be used to diagnose most patients with lung cancer and also to rule out false positive and negative cases.