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Biomedical subjects

M G Thomas

Publications and source records attributed to M G Thomas.

167 records · Page 10Linked to original sources
PubMedDate not supplied

Abnormal subcellular distribution of mature MUC2 and de novo MUC5AC mucins in adenomas of the rectum: immunohistochemical detection using non-VNTR antibodies to MUC2 and MUC5AC peptide.

Anti-mucin variable number tandem repeat (VNTR) antibodies have been used previously to demonstrate the de novo presence of MUC5AC and MUC6 mucin in colorectal adenomas and increased synthesis of MUC2, the major secreted mucin in normal colorectal mucosa. Here we examined secreted mucins in tubular, tubulovillous and villous adenomas of the rectum using non-VNTR antibodies designed to assess mature mucin. Mucin gene messenger RNAs were detected by in situ hybridization. The anti-MUC2 non-VNTR antibody in the goblet cells of adenomas revealed a staining pattern of increased cytoplasmic, Golgi and membrane staining with no change in goblet vesicle reactivity compared with normal controls. In addition, blank goblet cell vesicle immunostaining for MUC2 was found in the transitional mucosa adjacent to all types of adenoma. Although a trend to overexpression of MUC2 was observed with in situ hybridization this was not detected with immunohistology. De novo synthesis of MUC5AC, but not MUC5B or MUC6 mucin was seen in all adenomas and transitional mucosa using immunohistochemistry. There was no correlation of MUC2 or MUC5AC mucin with polyp size or the grade of dysplasia using the non-VNTR antibodies. This study demonstrates that anti-mucin non-VNTR antibodies reveal a different subcellular-localization in rectal adenomas compared with normal colorectal mucosa. Further, this pattern is in contrast to that reported for anti-mucin VNTR antibodies. Combined use of these reagents may benefit future assessment of these cancers.

Adenoma↗
PubMedDate not supplied

Epidemiology of pertussis.

The epidemiology of pertussis may be approximately represented by an equation that relates the rate of increase in incidence of pertussis to the contagiousness of pertussis, the number of contacts per case, and the proportion of the population susceptible. By use of this equation it is possible to estimate the proportion of the population that is susceptible to pertussis at any stage of a pertussis epidemic. Data from pertussis epidemics in England and Wales in the last 10 years suggest that the level of immunity to pertussis has fluctuated between 92% and 94% of the total population. During this period pertussis vaccine uptake in England and Wales has risen from a low of 30% to the present level of approximately 80%. Comparison with other countries suggests that a further increase in vaccine uptake to levels above 90% would reduce pertussis incidence to less than one-tenth of its present level. These aspects of pertussis epidemiology are likely to be of relevance in the planning and interpretation of future pertussis vaccine trials, such as are expected to start in England shortly.

Disease Outbreaks↗
PubMedDate not supplied

Effect of enteral feeding on intestinal epithelial proliferation and fecal bile acid profiles in the rat.

The preservation of colonic mucosal mass requires the presence of feces; thus, colonic hypoplasia develops with enteral feeding. Fermentable soy fiber may maintain fecal bulk and prevent mucosal atrophy. We therefore compared the effects of Enrich (containing soy fiber) with Ensure (fiber-free) on mucosal mass, fecal bile acids, and cell proliferation in the rat. Sprague-Dawley rats (n = 20) were randomized into groups receiving either standard rat food, Enrich, or Ensure. After 4 weeks, rats were weighed and killed at intervals after administration of vincristine sulfate (1 mg/kg intraperitoneally), which was given to induce metaphase arrest within the intestinal crypts and to allow calculation of crypt cell production rate. Fecal free bile acids and neutral steroids were analyzed using gas-liquid chromatography and gas-liquid chromatography mass spectrometry. Nucleic acid concentrations in the small and large intestine and crypt cell production rate in the small bowel were unaffected by diet. In the proximal large bowel, both enteral diets produced a marked reduction in crypt cell production rate to values only 5% to 7.5% of control values (p < .001). In the midcolon of rats fed Ensure, there was a similar reduction, but this hypoplastic effect was completely prevented by Enrich. Without an elevation in the lithocolic acid to deoxycholic acid ratio, secondary bile acid concentrations were increased in rats receiving Enrich (p < .05 to .01) but not in those receiving Ensure. Thus, fermentable soy fiber diets may prevent the midcolonic mucosal hypoplasia induced by enteral feeding.

Animals↗
PubMedDate not supplied

Prevalence and patterns of drug use among high-school students: a replicated study.

A survey of high-school students in Delhi, carried out in 1975, revealed that 34.3 per cent of respondents used psychoactive drugs in the preceding year. The percentage of users of psychoactive substances other than alcohol and tobacco was 15.5 per cent. The percentage prevalence rates by substance ranked as follows: tobacco (35.1), alcohol (26.2), cannabis (12.0), tranquillizers (8.9), amphetamines (5.8), sedatives (4.9) and opium (1.3). The survey was replicated in the same classes of students in 1976. It revealed that the non-response vote was slightly lower, as was also involvement with drugs, though the difference between prevalence rates of drug use in the two years was not statistically significant.

Adolescent↗