Biomedical subjects

S Kannan

Publications and source records attributed to S Kannan.

133 records · Page 8Linked to original sources

PubMedDate not supplied

Potential biological markers for the staging of tumor progression in oral mucosa: a multivariate analysis.

A recent trend in cancer control programmes is the development of early detection strategies and chemoprevention of premalignant lesions. The present study evaluates the potential of selected markers in the biological staging of tumor progression in oral mucosa for better management of the disease. The expression patterns of various cytokeratin protein types such as 10/11, 13 & 16, 19, 18, 14 and pancytokeratin, involucrin, ras p21, epidermal growth factor (EGF) and its receptor (EGFR) were assessed immunohistochemically in various stages of tumor progression in oral mucosa. Statistical analyses such as the Kruskal-Wallis one-way ANOVA, Spearman's rank correlation and multiple regression analysis were carried out to see which proteins have a significant association with tumor progression in oral mucosa. Statistical analysis showed that the expression patterns of cytokeratin types 10/11, 14 and 19, involucrin and epidermal growth factor were significantly correlated with tumor progression in oral mucosa in both univariate and multivariate analysis. Thus the biological stage of a lesion can be calculated from the multiple regression equation derived for these proteins, which could be more useful in assessing the stage of tumor progression in oral mucosa than histopathological grading.

Biomarkers, Tumor↗

PubMedDate not supplied

Comparative leprosy vaccine trial in south India.

This report provides results from a controlled, double blind, randomized, prophylactic leprosy vaccine trial conducted in South India. Four vaccines, viz BCG, BCG+ killed M. leprae, M.w and ICRC were studied in this trial in comparison with normal saline placebo. From about 3,00,000 people, 2,16,000 were found eligible for vaccination and among them, 1,71,400 volunteered to participate in the study. Intake for the study was completed in two and a half years from January 1991. There was no instance of serious toxicity or side effects subsequent to vaccination for which premature decoding was required. All the vaccine candidates were safe for human use. Decoding was done after the completion of the second resurvey in December 1998. Results for vaccine efficacy are based on examination of more than 70% of the original "vaccinated" cohort population, in both the first and the second resurveys. It was possible to assess the overall protective efficacy of the candidate vaccines against leprosy as such. Observed incidence rates were not sufficiently high to ascertain the protective efficacy of the candidate vaccines against progressive and serious forms of leprosy. BCG+ killed M. leprae provided 64% protection (CI 50.4-73.9), ICRC provided 65.5% protection (CI 48.0-77.0), M.w gave 25.7% protection (CI 1.9-43.8) and BCG gave 34.1% protection (CI 13.5-49.8). Protection observed with the ICRC vaccine and the combination vaccine (BCG+ killed M. leprae) meets the requirement of public health utility and these vaccines deserve further consideration for their ultimate applicability in leprosy prevention.

Adolescent↗

PubMedDate not supplied

Direct detection of diarrheagenic Aeromonas from faeces by polymerase chain reaction (PCR) targeting aerolysin toxin gene.

Detection of diarrheagenic Aeromonas specific aerolysin toxin (Aer) gene by PCR based assay and isolation, identification of diarrhea causing Aeromonas from faeces by culture methods were carried out in the Division of Active Surveillance, National Institute of Cholera and Enteric Diseases (NICED), Kolkata, India for a period of 12 months. Out of 602 faecal samples collected from patients with acute diarrhea admitted in Infectious Diseases (ID) Hospital, Kolkata, 68 (11.29%) samples were found to be possessing Aer gene by PCR technique. The conventional culture methods using selective media yielded only 64 (10.6%) Aeromonas strains from the same faecal samples. The different Aeromonas species possessing Aer gene identified by PCR based technique include A. hydrophila (55.8%), A. caviae (17.6%), A. veronii (10.2%), A. schubertii (4.4%), A. jandaei (2.9%) and A. trota (8.8%). The isolation and identification of Aeromonas by routine culture did not detect enterotoxigenic A. trota present in four diarrheal faecal samples. The failure of the growth of enterotoxigenic A. trota on selective media may be attributed to the ampicillin susceptibility of those strains. The quality control studies revealed that PCR method for the direct detection of Aer gene from the faeces has the sensitivity of 100% and specificity of 98%.

Adolescent↗

PubMedDate not supplied

Significance of silver-stained nucleolar organizer regions in early diagnosis and prognosis of oral squamous cell carcinoma: a multivariate analysis.

Argyrophilic nucleolar organizer regions (AgNORs) appear to be of diagnostic and prognostic significance in different types of human tumour. The present study examined the AgNOR counts in normal, premalignant and malignant oral mucosa to evaluate their potential as a biological marker for tumour progression and a prognostic predictor for treatment outcome in oral carcinomas. The Spearmann's rank correlation analysis between AgNOR counts and various stages of tumour progression in oral mucosa exhibited a highly significant positive coefficient (r(s) = 0.7969; p < or = 0.001), thus indicating the role of AgNORs in the early diagnosis of potentially malignant oral leukoplakia. When analyzing the prognostic significance of AgNOR in oral carcinomas, mean count > 2.8 concurred with poor prognosis in both univariate and multivariate analysis. Along with AgNOR counts, the T-status of disease was also found to be an independent predictor for treatment outcome in multivariate analysis. Thus T3 and T4 tumours, with mean AgNOR counts more than 2.8, are aggressive and may exhibit resistance to current treatment protocols.

Carcinoma, Squamous Cell↗

PubMedDate not supplied

Inter-observer agreement and clinical diagnosis of leprosy for prophylaxis studies.

Clinical diagnosis is still the most useful tool for detecting early cases of leprosy in field research. In prophylaxis studies accuracy of clinical diagnosis of leprosy is important during intake as well as for measuring efficacy of the intervention. This paper reports our observations regarding the extent of inter-observer variations in clinical diagnosis of leprosy and its implications for a prophylaxis study. Information on 225 suspects and cases of leprosy, each examined independently by three senior workers after initial standardization, was used for this purpose. Agreement among the examiners regarding the presence of skin patch, thickened nerve trunk and sensory deficit was fairly high (Kappa = 0.7). Agreement on the presence of infiltration in a skin patch was not satisfactory (Kappa = 0.4-0.5). It was observed that in clinical diagnosis of leprosy, presence of skin patch and sensory deficit, as well as thickened nerve trunk and related anaesthesia were correlated observations. The influence of inter-observer variations on defining leprosy problem in the community can be quite large. The paper suggests some ways of overcoming the problem.

Adult↗

PubMedDate not supplied

The immunohistochemistry of solid tumours: potential problems for new laboratories.

Immunohistochemistry has become an important tool for tumour typing and has the potential to improve the histopathological diagnosis of neoplasms. However, the large number of publications on the different aspects of the technology are often contradictory. In many instances the immunochemical reactions may not be reproducible and can create problems in the diagnosis of certain tumours. The use of optimal materials and techniques enhance the sensitivity, specificity and reproducibility of these methods. In this article we discuss the common problems of tissue preparation, and antigenic variation, distribution and presentation. However, immunopathological diagnosis has to be accompanied by an in-depth and fundamental understanding of basic immunochemistry and diagnostic immunohistochemistry has to be interpreted in the context of a standard clinical and histopathological examination.

Antigenic Variation↗

PubMedDate not supplied

Biochemical variations of male scent markers alter the attractiveness in the female rats, Rattus norvegicus.

The present investigations were carried out to evaluate whether the variations in the biochemical composition of male scent markers may cause differences in the attractiveness to female rats, Rattus norvegicus. The scents originated from the preputial glands, cheek glands, skin, urine, faeces, and ventral body rubbing. The females responded to all these scent sources of male but they spent more time to ventral body rubbing, preputial glands and urine. However, the duration of response was differ from one another, which may be due to the quantitative and qualitative variations of biochemical composition of male scent sources. The females responded to male odours in the following order; ventral body rubbing, preputial gland, urine, cheek gland, skin extract and finally to the faeces as observed in the present investigation. Thus, The present work concluded that the lipids play a major role in the sexual attraction through the sex pheromones released by the male to the females of the same species.

Animals↗