Intelligibility of speech under nonexponential decay conditions.
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Acoustics↗
Biomedical subjects
B S Ramakrishna
Publications and source records attributed to B S Ramakrishna.
Prevalence of intestinal pathogens in HIV patients with diarrhea: implications for treatment.
Patients infected with the human immunodeficiency virus (HIV) commonly experience diarrhea at some time during their illness. A variety of enteric pathogens are identified in 50-80% of these patients, depending on the intensity of the diagnostic work-up that is done. In addition to the common enteric pathogens, several unusual enteric pathogens are recognized to cause diarrhea especially in HIV patients. These include protozoan parasites such as Cryptosporidia, Isospora belli, Cyclospora cayatenensis and Microsporidium species bacteria such as enteropathogenic Escherichia coli and Mycobacterium avium-intracellulare, fungi including Candida albicans and Histoplasma capsulatum, and viruses such as astroviruses and caliciviruses. Diagnosis of these infections sometimes involves special procedures not readily available every where, and empiric therapy based on knowledge of the likely pathogens has been advocated for developing countries. This article reviews the currently available data on geographic variation of enteric pathogens in HIV patients with diarrhea and outlines a rational strategy for empiric therapy of these patients.
Animals↗
Human intestinal capillariasis: first report from India.
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Animals↗
Hydroxyl radical formation in human gastric juice.
The hydroxyl radical is the most potent free radical derived from oxygen, and has been implicated in damage caused to the gastroduodenal mucosa. The ability of human gastric juice to generate hydroxyl radicals has been investigated in 54 adults with endoscopically normal gastroduodenal mucosa and in 39 patients with chronic duodenal ulcer. Hydroxyl radical production was measured by the formation of formaldehyde from dimethylsulfoxide. Unlike other body fluids, this reaction could proceed without the extraneous addition of catalysts such as hydrogen peroxide (H2O2), ascorbate and iron. Measurement of H2O2, iron and ascorbate showed that these catalysts are already present in the gastric juice. There was no significant difference in the concentration of these components in gastric juice between normal subjects and patients with duodenal ulcer, except that H2O2 levels were slightly higher in duodenal ulcer patients. Although generation of free radicals has been investigated in other body fluids, this is the first reported case regarding the production of these active species in normal human gastric juice. Since hydroxyl production is not significantly enhanced in duodenal ulcer, we suggest that attention may be turned to mucosal antioxidant defences in this disease.
Adolescent↗
Prevalence of Helicobacter pylori in southern Indian controls and patients with gastroduodenal disease.
The spiral organism Helicobacter pylori has been causally implicated in the genesis of various gastroduodenal diseases. Since these diseases are common in southern India, this study was undertaken to determine the prevalence of H. pylori in the gastric mucosa of asymptomatic adults and patients with various gastroduodenal diseases. H. pylori was detected in the gastric mucosa of 25 of 30 (83.3%) normal volunteers. Prevalence rates in the disease groups were also high, and included 38 of 41 patients with duodenal ulcer (92.6%), 13/16 with gastric ulcer (81.3%), and 85/119 subjects (71.4%) with non-ulcer dyspepsia. Light microscopic examination of the gastric mucosa provided the best method of detecting H. pylori. H. pylori colonization was significantly associated with histological abnormalities, mainly chronic atrophic gastritis (147) and superficial gastritis (11), while only three of 161 H. pylori positive patients had histologically normal antral mucosa. Ultrastructural examination revealed changes in the apical complex of the gastric mucosal cells in response to bacterial adhesion, with mucus depletion and cellular damage. Bacteria were also noted disrupting the tight junctions and entering the intercellular spaces. The high prevalence of H. pylori infection may explain the high incidence of gastritis, duodenal ulceration and gastric carcinoma in this population. However, in this population, the prevalence of infection in asymptomatic individuals was nearly as high as that in duodenal ulcer, underlining the need for further study to identify the differences in host response or bacterial pathogenicity that lead to the development of ulcer in only some individuals.
Adolescent↗
Colonization by Helicobacter pylori and its relationship to histological changes in the gastric mucosa in portal hypertension.
In order to investigate the relationship between Helicobacter pylori infection of the gastric mucosa and mucosal changes in portal hypertension, gastric fundic and antral biopsies were obtained from 66 patients with portal hypertension and 49 controls with non-ulcer dyspepsia (NUD). Gastric mucosa from portal hypertensive patients exhibited typical vascular dilatation and congestion, while mild dilatation of lamina propria blood vessels was not uncommon in NUD patients with histological evidence of gastritis. Colonization of the gastric mucosa by H. pylori infection was significantly less in portal hypertension (51.5%) compared to controls (75.5%; P < 0.01). The difference was more apparent in patients with marked vascular dilatation (18.8% colonization) compared to patients with minimal vascular dilatation (66.7%). H. pylori infection was significantly associated with active superficial gastritis (P < 0.001), and with atrophic gastritis (P < 0.001), in both study groups. H. pylori-negative superficial gastritis was significantly more common in portal hypertension (25/66 patients) than in controls (7/49; P < 0.05). H. pylori infection was not more common in patients who had undergone repeated sclerotherapy. The results suggest that the gastric mucosa of portal hypertension does not provide a hospitable environment for H. pylori colonization, particularly when mucosal congestion is marked. H. pylori infection does not add significantly to the gastropathy of portal hypertension.
Adolescent↗
Colonic mucosal antioxidant enzymes and lipid peroxide levels in normal subjects and patients with ulcerative colitis.
Oxygen-derived free radicals have been implicated in the pathogenesis of ulcerative colitis. Mammalian tissues contain antioxidant systems that offer protection from the damaging effect of these active species. In the present study, the activity of the antioxidant enzymes catalase, glutathione peroxidase, glutathione transferase and glutathione reductase were measured in rectal biopsies from patients with ulcerative colitis and compared with that obtained from normal subjects. A significant decrease in the activity of glutathione transferase was observed in ulcerative colitis (48.32 +/- 6.73 units/mg protein, mean +/- s.e.) compared to normal (68.20 +/- 6.83; P = 0.015). There was no difference in the activity of other antioxidant enzymes between controls and ulcerative colitis. Myeloperoxidase, a marker for neutrophil infiltration, was considerably increased in ulcerative colitis while malonaldehyde, the end product of lipid peroxidation, was not increased. The reduced activity of glutathione transferase in ulcerative colitis may be an additional factor in the pathogenesis of mucosal damage in this disease.
Adult↗
Hepatitis C virus genotype 6 infection in India.
We report two patients with chronic liver disease--a 46-year-old man and a 52-year-old woman, both from eastern India--who were found to be infected with hepatitis C virus genotype 6 strains. These strains have been previously reported only from Hong Kong and Southeast Asia.
Chronic Disease↗
Helicobacter pylori infection in India: the case against eradication.
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Duodenal Ulcer↗
Clofazimine induced enteropathy--a case highlighting the importance of drug induced disease in differential diagnosis.
A patient on treatment for multibacillary leprosy for the past three years, presented with episodes of abdominal pain. Since the patient improved with conservative management, clofazimine induced enteropathy was considered as a remote possibility. A review of the mucosal biopsies showed macrophages with crystal-storing spaces consistent with clofazimine deposition in the duodenum. This case highlights the need to consider and investigate drug-induced disease as part of the differential diagnosis.
Clofazimine↗
Intraoperative enteroscopy in obscure gastrointestinal hemorrhage.
Forty three patients were diagnosed to have obscure gastrointestinal hemorrhage (OGH) between January 1987 and April 1996. Pre-operative diagnostic investigations were useful in localizing the site of bleeding in 28 patients (65.1%). These included small bowel enema (n = 12), erythrocyte tagged scan (n = 8), Meckel's scan (n = 2) and selective visceral angiography (n = 7). Following complete evaluation all patients underwent exploratory laparotomy. At laparotomy 31 patients were found to have gross lesions. Intraoperative enteroscopy (IOE) could detect lesions in 9 of the remaining 12 patients.
Adult↗
Eosinophilic gastroenteritis--an Indian experience.
Eosinophilic gastroenteritis is an uncommon disorder with varied presentation. Records of 7 patients (6 men) with eosinophilic gastroenteritis, presenting to a large referral hospital over a 10-year period, were analyzed. The patients were young adults (mean age 32 years) with short duration (median 2 months) of illness. Symptoms included abdominal pain and vomiting (100%), weight loss (57%), diarrhea (43%) and abdominal distension (43%). Peripheral eosinophilia was present in all the patients. The diagnosis was made at duodenal (2 patients) or cecal (1) biopsy or surgical full-thickness jejunal biopsy (4). Three patients had predominantly mucosal disease (Klein type I), whereas two patients each had predominantly muscular (type II) and submucosal (type III) disease. Surgical resection was curative in one patient with type II disease. The other six responded to prednisolone, with complete resolution in one patient.
Adult↗