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Biomedical subjects

D Kothari

Publications and source records attributed to D Kothari.

17 recordsLinked to original sources
PubMed1999

Expression of MUC1 and MUC2 mucin gene products in Barrett's metaplasia, dysplasia and adenocarcinoma: an immunopathological study with clinical correlation.

AIMS: Changes in the histochemical characteristics of the surface epithelial mucins is the hallmark of Barrett's metaplasia. The study investigated the pattern of expression of MUC1 and MUC2 mucin gene products in Barrett's metaplasia, dysplasia and adenocarcinoma as possible indicators of increased malignant potential. METHODS AND RESULTS: Tissue sections from 51 patients with Barrett's intestinal metaplasia, nine with dysplasia (three indefinite) and 28 resected adenocarcinomas were stained with monoclonal antibodies to MUC1 and MUC2. The majority of the patients were men (70/88, 80%) who were treated over a period of 3 years. None of the patients with dysplasia or carcinoma were under surveillance at the time of presentation. All 51 biopsies with Barrett's metaplasia expressed MUC2 and MUC1 was consistently absent. Neither MUC1 or MUC2 were expressed in the dysplastic epithelium whether in its pure form (6/6) or when associated with carcinoma (26/28) (P < 0.005). Three biopsies which were initially classified as high-grade dysplasia expressed MUC1 and these turned out to be carcinomas on further investigations. MUC1 was also expressed in 12/28 (43%) of the adenocarcinomas and majority of these were poorly differentiated stage 3 tumours (P < 0.05). MUC2 was only positive in mucin-secreting carcinomas (4/28; 14%) irrespective of the tumour stage. CONCLUSION: Despite the large number of patients with Barrett's metaplasia and carcinoma, very few patients presented with dysplasia, implying that Barrett's oesophagus is a silent disease in the community presenting late as carcinoma. The study has demonstrated aberrant expression of MUC2 (an intestinal mucin) in Barrett's metaplasia and this expression is lost when the cells become dysplastic. The lack of MUC1 in dysplastic epithelium and its expression in carcinoma could be utilized as a marker which could differentiate dysplasia from carcinoma in mucosal biopsies. Furthermore, expression of MUC1 in advanced stage oesophageal cancers (as in breast cancer) suggests an unfavourable prognosis.

Adenocarcinoma↗
PubMed1999

Exposure limits of women in hot environment.

The tolerance of six women to work in hot environments was examined under four environmental conditions from 38 to 44 degrees C dry bulb temperature and 50 to 80 per cent relative humidity, i.e., 32 to 36.5 degrees C effective temperature [ET (normal scale)] in a climatic chamber. The subjects performed bicycle ergometric work at an intensity of 50 W and the exposure duration was determined by the cardiorespiratory, body temperature and sweating responses. At the limit of tolerance, the body core temperature (Tcr) reached over 38.5 degrees C and the heart rates attained a peak level (i.e., about 172 beats/min). The total oxygen demand decreased significantly with higher environmental load, particularly beyond 33.5 degrees C ET (N). While the tolerance time decrement was evident with the higher heat stress, on an average, an increase or decrease of every liter of total oxygen demand was equivalent to a 0.8 min change in the tolerance time. As such, the women volunteers were not susceptible to heat; only in extreme hot situations beyond 33.5 degrees C ET (N), they had unacceptable levels of physiological and psychophysical reactions. Based on the distribution of tolerance time of the women in different exposure conditions, the safe exposure times were estimated, which varied from 43 min [32.0 degrees C ET (N)] to 16 min [36.5 degrees C ET (N)].

Adult↗
PubMed1997

Human heat tolerance in simulated environment.

The heat tolerance of 11 male volunteers were examined under seven climatic conditions in a climatic chamber. The conditions were 38 to 49 degrees C dry bulb temperature and 45 to 80 per cent relative humidity, i.e., 32.3 to 40 degrees C effective temperature-basic [ET(B)]. The ET(B) values were equated to other heat stress indices, e.g., WBGT (Wet-bulb Globe Temperature Index) and Oxford Index. The subjects did ergometric work at an intensity of 60 per cent VO2max. The exposure durations were decided by the cardiorespiratory, body temperature and sweating responses. Of the climatic conditions studied, at 35.4, 38, 39 and 40 degrees C ET(B), the body core temperature (Tcr) reached over 39 degrees C and heart rates attained 172 to 182 beats/min, which were taken as the tolerance limit. The total oxygen demand significantly varied with the increase in environmental warmth, i.e., increase or decrease of one litre of oxygen demand was equivalent to one minute change in tolerance time. The volunteers were not susceptible to heat; only in extreme hot situations beyond 35.4 degrees C ET(B), were unacceptable levels of physiological and psychophysical reactions seen. The study suggests the acceptable and tolerable limits for human exposure in heat: (i) acceptable at 38 to 38.2 degrees C Tcr for a tolerance time of 80 to 85 min; and (ii) the tolerable limit of short duration (40-45 min) at 39 degrees C Tcr that corresponded to 31.5 and 36.5 degrees C ET(B).

Adolescent↗
PubMed1996

Human work capacity under combined stress of work and heat.

The working capacity of young, healthy, unacclimatized men (N = 11) was studied under long-duration (8 to 9 days) exposure to combined work and heat (dry and humid). The dry (Gr A, N = 5) and humid (Gr B, N = 6) groups were exposed to 41.3 +/- 0.6 degrees C DB, 40-50% RH and 39.2 +/- 0.6 degrees C DB, 70-80% RH, respectively, for all days of exposure. The experimental protocol was divided into: (i) direct determination of maximal oxygen uptake (VO2max) by stepped increases in bicycle ergometry everyday in the morning in the initial hours before exposure to heat, after which the recovery process of oxygen debt contraction was examined; and (ii) exposure to heat in a climatic chamber for 2 h where the subjects performed two spells of ergometric work (10 to 12 min each) at a relative intensity of 50 +/- 12 to 69 +/- 11% VO2max. The average heat exposure time for Gr A was higher (108 +/- 12 min) as compared to Gr B (95 +/- 10 min), but Gr B sustained a high heat load as reflected from the high deep-body temperature maintained during the exposure. The high body temperature load of Gr B had a significant effect on the cardiorespiratory capacity, indicating an upward trend in VO2max. This was statistically significant (p < 0.05) for the first four days of exposure. Subjects of Gr B had a relatively higher working capacity compared to those in Gr A on all days. The VO2max and analysis of the fractions of oxygen debt contraction (fast and slow component) indicated that the subjects showed a better training/heat acclimatization effect under hot, humid conditions.

Adult↗
PubMed1987

Calcium antagonist.

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Calcium Channel Blockers↗
PubMed1986

Noonan syndrome.

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Abnormalities, Multiple↗
PubMed1975

Comparison of antibiotic discs from different sources.

Antibiotic discs from Oxoid, Mast, AB Biodisk, Difco, and Baltimore Biological Laboratories were compared, where discs of similar antibiotic content were available, in diffusion-sensitivity tests against organisms of known sensitivity. Discs from Oxoid and Mast gave zones 1-5 mm larger than discs from other manufacturers with penicillin 2 units, ampicillin 10 mug, cephalothin 30 mug, methicillin 10 mug, carbenicillin 100 mug, erythromycin 15 mug, chloramphenicol 50 mug, and trimethoprim 1-25 mug, while discs containing aminoglycoside antibiotics, lincomycin, fusidic acid, tetracycline, nalidixic acid, penicillin 10 units, and polymyxin B gave similar zone sizes whatever the source. Where tested, different batches of single discs from the same source did not vary significantly in antibiotic content as indicated by variation in zone size; but with some antibiotics Multodisks gave larger zones than single discs from the same source. The implications of these differences are discussed.

Anti-Bacterial Agents↗
PubMed1975

Comparison of tablets and paper discs for antibiotic sensitivity testing.

The value of tablets and paper discs as reservoirs of antimicrobial agents for use in sensitivity testing was compared. Antibiotics that were unstable in paper discs showed no demonstrable loss of activity in tablets over a period of 50 days under adverse storage conditions. The antibiotic content of commercially prepared tablets is very high in comparison with the accepted content of paper discs used in Britain, but not all of the agent is released from tablets during tests. Comparison of the size of zones of inhibition around tablets and standard paper discs indicated that the amount of the various agents released from the tablets varied between 2-6% and 69% of the stated content. In tests of the sensitivity of a range of common pathogenic organisms, the results obtained with the tablet method--when interpreted as recommended by the manufacturer--were generally similar to those obtained with a paper disc method commonly used in British laboratories. In 47% of tests with aminoglycoside antibiotics, however, strains sensitive by the disc method were 'intermediate' or resistant by the tablet method. As with paper discs, it was necessary to press the tablets on to the medium. With adjustment of the 'effective antibiotic content of tablets to bring it into line with the accepted content in paper discs, the stability of antibiotics in the tablets might make them an acceptable alternative to paper discs.

Anti-Bacterial Agents↗
PubMed1974

The reliability of methicillin sensitivity tests on four culture media.

The influence of culture medium, incubation temperature, and antibiotic content on the reliability of methicillin disc-sensitivity tests on strains of Staphylococcus aureus was evaluated. Tests were performed with an inoculum giving semiconfluent growth of colonies on four media, with 5-mug and 10-mug methicillin discs at incubation temperatures of 30, 35, and 37 degrees C. With Sensitest agar and Mueller-Hinton agar at 35 degrees C or below, methicillin resistance was reliably detected. On DST agar and Wellcotest agar discrimination between sensitive and resistant strains was possible only at 30 degrees C. On Wellcotest agar and DST agar it was not possible to detect methicillin resistance in one resistant strain at any temperature. For sensitive and resistant strains, the use of a 5-mug disc allowed greater differentiation than the 10-mug disc.

Culture Media↗