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Biomedical subjects

V I Mathan

Publications and source records attributed to V I Mathan.

At least 73 records · Page 4Linked to original sources
PubMed1985

A correlative study of etiology, clinical features and rectal mucosal pathology in adults with acute infectious diarrhea in southern India.

For detailed etiological studies we isolated invasive enteric bacterial pathogens in 16, non-invasive pathogens in 13 and no pathogens in 11 of 40 adults with untreated acute diarrhea of less than 5 days duration at a tertiary care hospital in southern India. It was possible to establish a system for the objective assessment of the clinical severity of illness. Hemorrhage in the rectal mucosal lamina propria. especially pericryptal, was a striking feature in rectal biopsies. This was associated with a vascular lesion with endothelial damage. The prevalence of the vascular lesion did not correlate with the etiological agents or the severity of the histological abnormality in the rectal mucosa. However, there was a good correlation between the presence of vascular abnormalities and clinical severity. While the vascular changes could be the result of non-specific trauma to the rectal mucosa due to diarrhea, it is suggested that they may have an as yet unknown role in determining clinical severity.

Adult↗
PubMed1984

Isolation and identification of enteroviruses from faecal samples in a differentiated epithelial cell line (HRT-18) derived from human rectal carcinoma.

A human rectal carcinoma-derived differentiated epithelial cell line, HRT-18, was inoculated with faecal samples in an attempt to grow coronavirus-like particles (CVLP), which are widely prevalent in human stools in southern India. While CVLP did not grow in this cell line, a variety of enteroviruses were isolated from 48 of the 114 stool samples from healthy controls and patients with diarrhoea. The results suggest that human gastrointestinal tumour-derived differentiated epithelial cells in continuous culture may be useful for the primary isolation of enteroviruses and merit further study.

Adult↗
PubMed1984

Absorption of nutrient energy in southern Indian control subjects and patients with tropical sprue.

Fecal energy excretion was measured by bomb calorimetry, in a group of 30 healthy volunteers and 15 patients with tropical sprue, to determine the absorption of nutrient energy. The mean energy absorption in the healthy volunteers (91.6%) was less than in similar subjects in temperate climates. The reduction of energy absorption in the volunteers, who all have tropical enteropathy, suggests that this condition leads to wastage of 5% of energy intake. In patients with tropical sprue the energy absorption was significantly lower. A strict metabolic balance study was not essential to detect energy malabsorbers.

Adult↗
PubMed1984

A common-source epidemic of mixed bacterial diarrhea with secondary transmission.

An epidemic of acute diarrhea in a village in southern India in 1972 was associated with a high rate of isolation of enteric pathogenic bacteria from the patients and lasted for three months. There was no significant association between the prevalence of enteroviruses or parasites and cases of diarrhea. The epidemic started as a common-source outbreak due to the contamination of well water, and there were many secondary cases probably due to a person-to-person spread. The illness did not produce chronic diarrhea or malabsorption.

Adolescent↗
PubMed1983

Faecal free fatty acids in tropical sprue and their possible role in the production of diarrhoea by inhibition of ATPases.

Faecal excretion of fatty acids is increased in patients with tropical sprue because of unabsorbed dietary fatty acids. The excretion of fatty acids correlates well with faecal wet weight. In vitro unsaturated fatty acids inhibited Na K-ATPase and Mg-ATPase isolated from basolateral membranes of enterocytes and colonocytes. These findings are a possible explanation for the observed abnormalities in water and electrolyte absorption by the colon in patients with tropical sprue and steatorrhoea.

Adenosine Triphosphatases↗
PubMed1983

Studies of intestinal lymphoid tissue. VII. The secondary nature of lymphoid cell "activation" in the jejunal lesion of tropical sprue.

Morphometric techniques were used in the evaluation of lymphocyte morphology and activity in tropical sprue. jejunal biopsies from control subjects (8), patients with epidemic disease (7), patients with endemic disease (11), and subjects who had recovered from sprue (4) were analyzed blindly. In patients with sprue, lymphocytes were increased significantly within crypt (but not surface) epithelium. Immunoblasts (greater than 6 mu in diameter) were increased by 5% over control subjects. Group means for lymphocytic mitotic indexes were also significantly raised, while flux ratios only differed significantly between endemic sprue patients and control subjects. The lymphocytic infiltration was distributed focally in the upper crypt and crypt-villus interzones. Analysis of epidemic cases (presenting within 4-28 days) revealed detectable changes in lymphocyte behavior only after 3 weeks' illness, whereas mucosal lesions and malabsorption were already established during the first week. These data indicate that lymphocyte activation, suggestive of a local cell-mediated immune reaction, does occur in tropical sprue but is secondary to damage already inflicted on enterocytes and their function.

Adult↗
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

Prevalence of Campylobacter fetus subsp. jejuni in healthy populations in southern India.

Campylobacter fetus subsp. jejuni was isolated from the feces of 14.8% of a random sample of the healthy population of rural southern India. The rate of isolation was highest in preschool children. This finding emphasizes the need to identify markers of pathogenicity in strains of C. fetus subsp. jejuni, which so far are identified only by cultural characteristics. The pathogenic role of this organism in patients with diarrhoea in tropical developing countries can be understood when such markers of pathogenicity are found.

Adolescent↗
PubMed1982

Water and electrolyte absorption by the colon in tropical sprue.

A defect in colonic absorption of electrolytes and water was demonstrated in patients with tropical sprue by perfusing the colon with normal saline containing a non-absorbable marker. Colonic water absorption correlated negatively with stool weight and was abnormal in patients with steatorrhoea. The possible mechanisms producing this defect are discussed. This defect may be related to colonocyte damage produced by unabsorbed unsaturated fatty acids in patients with steatorrhoea.

Colon↗
PubMed1982

The relationship between hypoalbuminaemia and the radiological appearances of the jejunum in tropical sprue.

Hypoalbuminaemia has been implicated as a possible cause of the radiological abnormalities of the small intestine in tropical sprue. Barium follow-through examination was performed in 35 southern Indian patients with documented tropical sprue, and jejunal width and fold pattern abnormalities were compared with those of a local age-matched control group. Although hypoalbuminaemia was present in 66% of patients with tropical sprue, in only one case was an increase in jejunal calibre associated with a serum albumin concentration below 27 g/l, the threshold below which jejunal dilatation occurs in hypoalbuminaemia alone. These findings suggest that other factors, such as the extent of the mucosal injury, are likely to be more important than hypoalbuminaemia in producing jejunal dilatation in this condition. Abnormalities of fold pattern occurred more frequently than increase in jejunal calibre and appear to be a more sensitive indicator of disease.

Adolescent↗
PubMed1981

Evidence regarding the minimal daily requirement of dietary vitamin B12.

The minimal daily requirement of dietary vitamin B12 is defined as that amount which must be ingested in the diet to prevent the occurrence of megaloblastosis, anemia, or other manifestations of vitamin B12 deficiency. An attempt has been made to define this requirement by studying hematological responses to varying amounts of the vitamin in five south Indian subjects with vitamin B12 deficiency anemia (one due to gastric atrophy and four due to dietary deficiency). Amounts ranging from 0.07 to 0.25 micrograms of dietary vitamin B12 were shown to be inadequate but amounts ranging from 0.3 to 0.65 microgram were adequate or possibly more than adequate. It is concluded that the minimal daily requirement of dietary vitamin B12 for the average south Indian adult is in the region of 0.5 microgram/day and that an intake of 1.0 microgram/day would cover the needs of the vast majority of the population and allow a wide margin of safety.

Adult↗
PubMed1981

Plasma lipids in tropical sprue.

Previous studies indicated that many patients with tropical sprue in southern India have triglyceride accumulation within the cells of the intestinal mucosa. This could be due to essential fatty acid deficiency as a result of steatorrhea in subjects on a diet normally low in linoleic acid. Plasma lipids have, therefore, been studied in patients with tropical sprue and the results compared to values observed in healthy controls. The low intake of linoleic acid was found to be adequate to maintain normal levels of arachidonic acid and to repress the formation of 5,8,11-eicosatrienoic acid in rural controls. Patients with tropical sprue had decreased levels of plasma linoleic acid, raised monoenoic fatty acids and the appearance of 5,8,11-eicosatrienoic acid in the lecithin fraction. All of these observations indicate essential fatty acid depletion although unequivocal evidence of essential fatty acid deficiency was not present in any of the patients. The degree of essential fatty acid depletion observed is unlikely to be the cause of the mucosal accumulation of triglyceride in tropical sprue.

Cholesterol↗
PubMed1981

One-hour serum xylose as an absorption test in the tropics.

The 1-hour serum xylose (surface area corrected) as an indication of xylose absorption after 5 g oral D-xylose has been compared with the 5-hour urine excretion test in a tropical population. The study confirmed that the peak serum xylose concentration occurs at 1 hour and that correction to a constant body surface are improves the discrimination between subjects with normal and impaired xylose absorption. The significantly lower reference range for the 1-hour surface area corrected serum xylose (0.55-1.11 mmol/l) compared to the UK figure reflects the reduced absorptive capacity of the jejunum, a result of tropical enteropathy. In view of the difficulties in obtaining accurate urine collections in tropical countries, especially in field studies, it is recommended that the 1-hour serum xylose (surface area corrected) should be adopted as the standard test of xylose absorption.

Body Surface Area↗
PubMed1981

Immunological changes in tropical sprue.

Immunological measurements in 85 southern Indian patients with tropical sprue were compared with two groups of controls, namely, 150 patients with gastrointestinal diseases not associated with malabsorption, and 57 normal asymptomatic subjects. A significant increase in intraepithelial lymphocytes in jejunal surface and crypt epithelium, related to the severity of the mucosal morphological abnormality, was the most significant finding in tropical sprue. Measurements such as increased serum concentrations of IgG, IgE, complement component C4 and orosomucoid, gastric parietal cell antibodies and lymphopaenia with a low peripheral blood T cell count, which were found in patients with sprue, differed significantly from the healthy control group but not from the group of gastrointestinal controls without malabsorption. The ability to produce functional antibodies was preserved in tropical sprue. The results suggest that the small intestinal enterocyte abnormality in tropical sprue is not the result of a primary immunological process but that the observed alterations are a sequelae of mucosal damage and compromised integrity of the mucosal barrier.

Adolescent↗