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Biomedical subjects

P Kumar

Publications and source records attributed to P Kumar.

At least 721 records · Page 40Linked to original sources
PubMed1979

Rectal IgE cells in inflammatory bowel disease.

Immunoglobulin-contained cells in the rectal mucosa of patients suffering from non-specific inflammatory bowel disease (IBD) were counted and compared with those in a control population. While the numbers of IgA, IgM, and IgG-containing cells in both ulcerative colitis and Crohn's disease did not differ from normal, both disease groups exhibited a marked increase in IgE-staining cells. This increase in IgE-cells did not correlate with severity, duration, or treatment of disease and it did not prove possible, using these immunological studies, to differentiate between Crohn's disease and ulcerative colitis.

Adolescent↗
PubMed1979

Isatin inhibition of rat testicular alkaline phosphatase. A non-allosteric phenomenon.

Isatin has been found to inhibit rat testicular alkaline phosphatase (EC 3.1.3.1) uncompetitively. The hyperbolic curve relating inhibition as a function of substrate concentration; the persistence of inhibition after the tertiary structure of the enzyme has been altered by heat denaturation, exposure to urea or papain digestion; the small changes in entropy, free energy and enthalpy in the presence of isatin, and the number of isatin molecules (n = 1.29) combining with one molecule of enzyme indicate the non-allosteric nature of inhibition.

Alkaline Phosphatase↗
PubMed1979

Isatin-enzyme interactions. VII. Mechanism of inhibition of rat kidney alkaline phosphatase.

Isatin has been found to inhibit rat kidney alkaline phosphatase (EC 3.1.3.1). The inhibition is dependent on isatin concentration and is of un-competitive type. The hydrolysis of disodium phenyl phosphate by the enzyme at different temperatures (17--37 degrees C) obeys the Arrhenius equation. Energy of activation in the absence and presence of isatin has been found to be 9.84 and 10.24 kCal/mol. The hyperbolic profile of isatin inhibition; the lowering of both Km and Vmax in the presence of isatin, and, small changes in enthalpy, free energy and entropy in the presence of isatin suggest a non-allosteric un-competitive inhibition of the enzyme.

Alkaline Phosphatase↗
PubMed1979

Isolation and characterization of endothelial cells from rat and cow brain white matter.

A procedure is described for obtaining pure cultures of endothelial cells from rat and cow brain white matter. The morphology of the tissue-cultured cells was studied by both light and transmission electron microscopy. Weibel-Palade bodies, described in the literature as specific for endothelial cells, appeared in small numbers in our cultured cells. Autoradiographic, scintillation counting, immunological and histochemical studies were performed. The usefulness of pure endothelial cell cultures is discussed.

Alkaline Phosphatase↗
PubMed1978

Nature of inhibition of rat testicular alkaline phosphatase by isatin.

Isatin has been found to inhibit rat testicular alkaline phosphatase (EC 3.1.3.1). That the inhibition is non-competitive as well as non-allosteric is evident from a) the hyperbolic curve relating inhibition as a function of inhibitor concentration; b) the small change in enthalpy, free energy and entropy; c) the number of isatin molecules associating with 1 molecule of the enzyme (n=1.29); and, d) the decrease in the values of both Km and Vmax in the presence of isatin.

Alkaline Phosphatase↗
PubMed1978

Deprenyl administration in man: a selective monoamine oxidase B inhibitor without the 'cheese effect'.

After pretreatment with the selective monoamine oxidase B inhibitor, (-)-deprenyl, in doses sufficient for complete inhibition of the platelet enzyme, 4 normal and 6 parkinsoniam volunteers (2 receiving levodopa and 2 levodopa plus carbidopa) suffered no adverse pressor reaction ('cheese effect') after challenge with oral tyramine in amounts considerably greater than those likely to be encountered in a normal diet. Nor did the levodopa-deprenyl combination itself result in a pressor response. Normal human intestinal mucosa was shown predominantly to contain the deprenyl-insensitive A form of the enzyme, which presumably degraded administered tyramine in the deprenyl-treated volunteers; even those receiving the drug for prolonged periods manifested no 'cheese effect', suggesting that the A form remained uninhibited. Intestinal monoamine oxidase A was able to oxidise dopamine, whereas in human platelet or striatum the amine is a monoamine oxidase B substrate. Like tyramine, oral phenylethylamine challenge with amounts greater than those known to be present in a normal diet similarly gave rise to no adverse reaction in (-)-deprenyl-treated subjects; the reasons for this remain to be determined.

Adult↗
PubMed1978

Induced chromosomal aberrations in somatic cells of Nigella sativa L. by mitomycin C.

A cytological study was carried out on root tips of Nigella sativa L. by treatment with Mitomycin C at 0.001% for six time intervals (10, 15, 20, 30, 40, and 50 min). The chromosomal abnormalities were increasingly proportionate to the increase in time of treatment. The seedlings treated with a 0.001% concentration of Mitomycin C for 10 min. did not show any significant effect. At other time intervals, the effect was observed to be quite significant. Beyond 40 min. treatment almost all the cells would become sticky. Thirty minutes' treatment showed significant effect, inducing various types of chromosomal aberrations in the anaphase, such as bridges and fragments of 34.13% and 48.07%, respectively.

Anaphase↗
PubMed1978

[Isatin-enzyme interactions. VI. Inhibition of rat kidney alkaline phosphatase].

Interaction of isatin with rat kidney alkaline phosphatase has been studied. Mode of attachment of isatin with the enzyme protein is most likely through amino group(s), which is also imperative for catalysis. Sulphydryl group(s) do not seem to be involved in enzyme action. Zinc is also needed for enzyme activity. Use of sulphydryl compounds suggests that isatin inhibition of the enzyme is through attachment at the metal site. However, this inhibition may not only be due to simple chelation of the metal by isatin.

Alkaline Phosphatase↗
PubMed1978

Induction of multipolar spindle in Allium sativum.

The effect of the polyene antifungal antibiotic aureofungin on the chromosomes of Allium sativum was examined. Mitotic studies showed chromosomal abnormalities of metaphase and anaphase. Besides these anomalies, the alteration of the spindle, i.e. tri- to multipolar condition, was also observed in treatment with 100 microgram treatment for 24 h, and 200 microgram for 12 h and 24 h. The chemical also inhibited cytokinesis; hence, the multinucleate condition was established. Due to fragmentation and unequal distribution of chromatin material, the nuclear volume was also observed to be variable.

Antifungal Agents↗
PubMed1977

Immunoglobulins in the jejunal mucosa in adult coeliac disease and dermatitis herpetiformis after the reintroduction of dietary gluten.

Cells containing immunoglobulin (IgA, IgG, IgM) have been measured and the distribution of extracellular and epithelial cell immunoglobulin assessed in treated patients with adult coeliac disease (ACD) and dermatitis herpetiformis (DH) before and after gluten was reintroduced to the diet. Patients with ACD and DH frequently had IgM and IgG cells above the normal range even before re-exposure to gluten, although the range of IgA cells was normal. In both diseases IgA and IgM cells increased after gluten with a proportionally greater rise in the latter, so that numbers of IgM cells, but not of IgA, exceeded the control range in all but one patient. There were increased quantities of IgA and IgM extracellularly in the lamina propria and in epithelial cells after challenge with gluten. Third component of complement was also found in some biopsies after re-exposure to gluten. These findings support the suggestion that gluten induces a humoral immunological response within the small intestinal mucosa and that both IgA and IgM systems are involved.

Adult↗