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Biomedical subjects

Eapen Thomas

Publications and source records attributed to Eapen Thomas.

5 recordsLinked to original sources

Intrapericardial giant left atrial appendage.

Contrary to what the name implies, the left atrial appendage is increasingly becoming an organ of clinical importance. Its role in the pathogenesis of thromboembolism is now well established. Enlargement of the appendage due to haemodynamic disturbances or anatomic weakness increases this risk, along with the potential for arrhythmia. We report a rare case of gross enlargement of the left atrial appendage within the pericardial cavity.

Atrial Appendage↗

Intestinal spirochetosis: a poorly understood infection causing chronic diarrhea.

A young man with chronic diarrhea for many years underwent extensive evaluation. Finally, based on multiple colonic mucosal biopsies from near-normal appearing mucosa, the cause was elucidated to be spirochetosis. This is an enigmatic condition where the spirochetes seem to attach to the epithelial lining of the small and large bowel, without significant underlying inflammation. Because of this reason, there is controversy whether it is a true diarrheal pathogen. Suggested treatments are discussed.

Anti-Infective Agents↗

Helicobacter pylori infection and oncogene expressions in gastric carcinoma and its precursor lesions.

Although it is fairly well accepted that Helicobacter pylori infection plays a significant role in causing gastric cancer, the exact mechanisms involved in its pathogenesis are unclear. We have examined the relationship between H. pylori infection and oncogene expression in different stages of disease progression from precursor lesions to gastric carcinoma. We used Diff-Quik stain to diagnose H. pylori infection and immunohistochemical stains against c-erbB-2, p53, ras, c-myc, and bcl-2 to determine expression of oncogenes. H. pylori infection was found in all cases of chronic gastritis, atrophic gastritis, intestinal metaplasia, and early gastric carcinoma, and in 16 of 30 (53%) cases of advanced gastric carcinoma. Overexpression of c-erbB-2 was found in 2 (7%) cases of advanced gastric carcinoma, which were H. pylori negative. Suppressor gene, p53, was overexpressed in 3 (30%) cases of intestinal metaplasia, 2 (33%) cases of early gastric carcinoma, and 18 (60%) cases of advanced gastric carcinoma. Of these 18 p53-positive advanced gastric cancer cases, 11 (61%) were H. pylori positive. Expression of ras p21 was found in 4 (40%) cases of H. pylori-negative normal mucosa, 10 (100%) cases of chronic gastritis, 1 (10%) case of atrophic mucosa, 6 (60%) cases of intestinal metaplasia, 2 (33%) cases of nonneoplastic mucosa adjacent to early gastric carcinoma, and 7 (23%) nonneoplastic mucosa adjacent to advanced gastric carcinoma, all of which showed H. pylori. No evidence of expression of either c-myc or bcl-2 was detected in any of the above-mentioned samples. The data suggest that H. pylori infection may increase expression of ras p21 proteins and induce p53 suppressor gene mutation early in the process of gastric carcinogenesis.

Chronic Disease↗

Comparison of cytotoxin genotypes of Helicobacter pylori in stomach and saliva.

We have previously reported a high prevalence of H. pylori DNA in saliva. In this study, the cytotoxin genotypes of H. pylori strains from both stomach and saliva were compared in 31 patients with gastritis and peptic ulcer. The cagA, vacA m1, vacA m2, and vacA s1 genotypes were analyzed by PCR. The 417 bp PCR products from three patients were also subjected to DNA sequencing analysis. There was 95% agreement between stomach H. pylori isolates and their corresponding saliva DNA in at least one cytotoxin genotype; 86% agreement with two cytotoxin genotypes; 59% agreement with three cytotoxin genotypes; and 27% agreement with all four cytotoxin genotypes studied. DNA sequencing from three patients showed 78.0%, 64.0%, and 66.9% homology of H. pylori from both sources, respectively. The data suggest that more than one H. pylori strain may exist in the stomach and saliva in the same patient.

Cytotoxins↗