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Biomedical subjects

M Mathan

Publications and source records attributed to M Mathan.

At least 37 records · Page 2Linked to original sources
PubMed1982

Chronic enterocyte infection with coronavirus. One possible cause of the syndrome of tropical sprue?

A man with a gastrojejunostomy and intestinal malabsorption was found to be excreting large numbers of coronavirus-like particles in his stools over a period of at least eight months. Coronavirus-like particles were found in vesicles in degenerating jejunal enterocytes in all of five jejunal biopsies. In a review of electron micrographs, similar structures were found in biopsies from three of 12 patients with classical chronic tropical sprue and in one patient with a sprue-like syndrome associated with agammaglobulinaemia. The hypothesis is advanced that infection with this virus may produce enterocyte damage and may be one cause of the syndrome of tropical sprue.

Coronaviridae Infections↗
PubMed1982

Rotavirus and acute diarrhoeal disease in children in a southern Indian coastal town.

Rotavirus was found by electron microscopy in the stools of 70.7% of a representative sample (368) of the 3355 children with acute diarrhoea admitted to hospital over a period of 16 months in Calicut on the west coast of India. The prevalence of the virus was high (nearly 100% of cases examined) in the period from November to January and lowest in May just before the onset of the monsoon. Prevalence was high (75.1%) in infants aged from 6 to 23 months, but was considerably lower in those under 6 months of age (34.8%). The management of cases and the planning of control measures for this disease are discussed in the light of knowledge of the high prevalence of rotavirus.

Acute Disease↗
PubMed1978

Jejunal microbial flora of southern indian infants in health and with acute gastroenteritis.

The microbial flora of the jejunal lumen of 28 infants with acute gastroenteritis was compared with that of a group of 10 normal infants. The jejunum of control subjects harboured an "oral" type of flora and in a few instances enterobacteria in small numbers. The concentrations of all but one of the groups of organism were higher in the patients than in controls, and the differences were of statistical significance for enterobacteria and lactobacilli. In eight subjects, the same pathogen was identified in the jejunum and the stool. In six subjects with rotavirus infection, there were almost no Gram-negative aerobic rods in the jejunum. The possible role of other Gram-negative aerobic rods in producing gastroenteritis is discussed. It is suggested that studies of jejunal flora are of considerable importance in assigning an aetiological role to bacteria in the causation of acute gastroenteritis.

Acute Disease↗
PubMed1978

Villoglandular adenoma of the duodenum.

Two cases of villoglandular adenoma of the duodenum presenting with features of peptic ulcer are reported. At surgery both patients had intussusception of the duodenum. One of them had carcinoma in situ. The literature is briefly reviewed, and the importance of keeping in mind this rather rare condition, even in areas where duodenal ulcer is widely prevalent, is emphasized.

Adenoma↗
PubMed1977

An antigenic subunit present in rotavirus infected faeces.

It has been found by immune electron microscopy that rotavirus-infected faeces, calf or human, contain an antigenic subunit associated with the inner of the two virus capsids. This internal component represents the group specific antigen for the rotavirus group and the subunit reacts with both homologous and heterologous antiserum. It can therefore be used in diagnostic tests and in this paper its use as a reagent for immunodiffusion is described.

Animals↗
PubMed1977

Aetiology of acute gastroenteritis in infancy and early childhood in southern India.

The aetiology of acute gastroenteritis was studied in 50 infants and young children. Bacterial pathogens were isolated in 33, enteropathogenic E. coli (EPEC), Salmonella, and Shigella being the commonest isolates. Rotaviruses were detected in the stools of 13 of the cases. All children with gastroenteritis in whom rotavirus was detected were seen during the months July to December. In 30 children who served as controls, EPEC were isolated in 6, but rotavirus was detected in none. It is concluded that infection with rotaviruses is a significant cause of morbidity in children with gastroenteritis in southern India.

Acute Disease↗
PubMed1976

Morphogenesis of fetal rat duodenal villi.

To study the structural features of fetal rat duodenal mucosa associated with histogenesis of villi, duodena from 15- to 19-day fetuses were examined by light and electron microscopy. The duodenal epithelium of 15- to 18-day fetuses was stratified. Distinctive junctional complexes associated with membrane-bounded vesicles and cilia-like structures were seen in the deeper epithelial layers at 15 and 16 days. Small lumina, designated "secondary lumina," lined with a variable number of microvilli developed between epithelial cells at these junctional complexes during the sixteenth through eighteenth days. Degenerative changes and exfoliation of superficial epithelial cells were obvious in 17- and 18-day fetuses. In 18-day fetuses, aggregates of mesenchyme had invaginated the basal aspect of the stratified epithelium. Concomitantly, the number of epithelial layers overlying these mesenchymal projections was decreased. In 19-day fetuses, well formed, short duodenal villi lined by a simple columnar epithelium which included goblet and endocrine cells were evident. Injection of ferritin into the main duodenal lumen of 17-day fetuses failed to reveal continuity between the main lumen and the secondary lumina. However, continuity between many secondary lumina and the main lumen was demonstrated in 18-day fetuses. Thus, major morphological features associated with villus formation in fetal rat duodenum include: (1) formation of many secondary lumina in primitive stratified epithelium, (2) eventual fusion of these lumina with the main duodenal lumen, by their continued growth coupled with exfoliation of degenerating superficial layers and (3) upward growth of mesenchyme towards the lumen as cell exfoliation and expansion of secondary lumina take place.

Animals↗
PubMed1975

Pleomorphic virus-like particles in human faeces.

Pleomorphic fringed particles bearing some resemblance to orthomyxoviruses and coronaviruses were seen in 90 percent of stools from south Indian children and adults but not in stools from neonates. This finding may be related to the abnormalities of intestinal structure and function common in this region of India.

Adult↗
PubMed1975

An electron-microscopic study of jejunal mucosal morphology in control subjects and in patients with tropical sprue in southern India.

The ultrastructure of the jejunal mucosa obtained by peroral biopsy from 7 control subjects and 12 patients with tropical sprue was studied. Compared with biopsies from control subjects in temperature zones, southern Indian control subjects showed minimal increase in lysosomes in surface epithelial cells, an occasional dark-staining degenerating epithelial cell in the upper two-thirds of villi, and an increase in cellular infiltration of surface epithelium and lamina propria. The jejunal epithelial cells of tropical sprue patients had abnormal microvilli, marked increase in lysosomes, increase in intracellular fat, and degenerative changes in rough endoplasmic reticulum and mitochondria. Two types of degenerating epithelial cells, designated pale and dark based on their staining quality, were seen in the villi. Pale staining degenerating cells were also seen in the crypts. The basement membrane region showed an amorphous deposit with many collagen fibers and fat droplets. The epithelial layer and lamina propria showed increased cellular infiltration. In one biopsy from a patient with sprue, particles of possible viral origin were seen.

Adolescent↗
PubMed1972

Structural features of the epithelio-mesenchymal interface of rat duodenal mucosa during development.

In fetal rats 5-7 days before birth, the duodenal epithelium is separated from mesenchymal cells by a well-defined basal lamina. By 3-4 days before birth, when small rudimentary villi are first seen, direct contact between epithelial and mesenchymal cells occurs by means of epithelial cell cytoplasmic processes which project through gaps in the basal lamina into the lamina propria. At contact sites, the epithelial and mesenchymal cell plasma membranes were less than 100 A apart but membrane fusion was not seen. In number and size these epithelial cell processes increase strikingly during the last 2 days of gestation, and they persist in large numbers until 7-10 days after birth. Thereafter, they decrease gradually in both number and size until 3-4 wk after birth, when the morphology of the epithelio-mesenchymal interface resembles that seen in adult rats, i.e., there are only rare epithelial cell processes which penetrate deeply into the lamina propria. The presence of a large number of epithelio-mesenchymal contact sites during the period of rapid growth and differentiation of duodenal mucosa may reflect epithelio-mesenchymal cell interactions which may facilitate the maturation of the duodenal mucosa.

Animals↗
PubMedDate not supplied

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↗
PubMedDate not supplied

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↗