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Biomedical subjects

J S Pasricha

Publications and source records attributed to J S Pasricha.

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

Demonstration of tyrosinase in the vitiligo skin of human beings by a sensitive fluorometric method as well as by 14C(U)-L-tyrosine incorporation into melanin.

Tyrosinase activity (Monophenol, dihydroxyphenylalanine: oxygen oxidoreductase EC 1.14.18.1) in vitiligo and normal epidermal homogenates of skin from human beings was measured by estimating beta 3,4-dihydroxyphenylalanine (dopa) by a highly sensitive fluorometric method described in this paper. The tyrosine activity in the vitiligo skin was about 4 to 37% of corresponding normal skin. The activity of tyrosinase in normal human skin from different individuals and from different regions of the body was in the range of 4 to 140 picomoles of beta 3,4-dihydroxyphenylalanine formed per min/mg protein of epidermal homogenate. The enzyme from vitiligo and normal skin was severely inhibited by substance(s) of low molecular weight. The enzyme exhibits a lag of about 4 hr in the absence of added beta 3,4-dihydroxyphenylalanine and 1 hr in presence of 5 microM dopa. Tyrosinase from the normal and vitiligo skin was inhibited by excess concentration of tyrosine. The homogenates from vitiligo skin could synthesize melanin from C14(U)-L-Tyrosine. The rate of tyrosine incorporation into melanin by the epidermal homogenates is increased by 3,4-dihydroxyphenylalanine (dopa) disproportionate to its effect on tyrosinase activity. Based on the data presented in this paper it is concluded that melanocytes are present in the vitiligo skin. A tentative hypothesis is put forward to explain the lack of melanin synthesis by the vitiligo skin under in vivo conditions, although melanocytes are present.

Cadaver↗
PubMed1979

Drugs causing fixed eruptions.

Forty patients having fixed drug eruptions were subjected to provocation tests. Twelve patients failed to complete the provocation tests while in the remaining, the causative drugs were shown to be tetracyclines (6), analgin (metamizole) (6), oxyphenbutazone (5), phenobarbitone (4), sulphadiazine (3), sulphaphenazole (2), penicillin (1), suphadimethoxone (1), Saridon (1), sulphadimidine (1) and sulphamethoxypryridazine (1). There was evidence of cross-sensitivity between tetracycline and demethylchlortetracycline and also between exyphenbutazone and phenylbutazone, but not between different sulphonamides, In 2 cases, the minimum dose of the drug capable of reactivating the lesions was 100 mg of sulphadiazine and 50 mg of Saridon respectively.

Antipyrine↗
PubMed1977

Vegetables responsible for contact dermatitis of the hands.

Fifty-three patients having contact dermatitis on the fingertips showed positive patch tests with several vegetables the commonest being garlic, onion, tomato, and carrot in that order of frequency. Of several preparations, made from garlic onion, tomato, and carrot, the juices used as such gave the maximum number of positive patch test reactions. Lyophilization of the juices led to false-negative patch tests in some cases. Patch tests in the controls were positive in some cases but these were probably cases of latent hypersensitivity, because some of them, like the patients, showed positive reactions even with the diluted juices. The antigens in garlic and onion were extractable in water, ether, acetone, or alcohol and were also present in the essential oils of these vegetables. Infrared spectra of the essential oils of garlic and onion were similar and showed straight chain acids, esters, and methylene groups. Clinically, there was no suggestion of cross-sensitivity between onion and garlic.

Antigens↗
PubMed1975

Treatment of pemphigus with cyclophosphamide.

Cyclophosphamide was ineffective in controlling acute disease activity in nine of eleven pemphigus patients, but when given during the remission phase even 50 mg cyclophosphamide per day was sufficient to prevent subsequent relapses in all the patients for quite long periods of follow-up. This small dose of cyclophosphamide could be given to outpatients and there were no side effects.

Administration, Oral↗
PubMed1975

Elimination of circulating antibodies. Attempts to eliminate antibodies circulating in rabbits using a fraction of normal human epidermis.

Rabbits were immunised with a fraction of normal human epidermis to produce circulating antibodies. In each experiment, half of the immunised rabbits were given a dose of the same antigen intravenously and the changes in the titres of antibodies were recorded. Doses of the antigen used in different experiments varied from 0.09 to 3.5 mg protein per rabor the first 24 h, followed by a secondary rise. Administration of corticosteroids together with the antigen intravenously could check this secondary rise in antibody titre. Repeated intravenous injections of the antigen led to severe anaphylactic reactions, while subcutaneously administered antigen produced no significant effects.

Animals↗
PubMed1975

Evaluation of cryo-stimulation test for the diagnosis of cold urticaria.

A cryo-stimulation test performed on 300 allergic and non-allergic individuals showed that this test is positive in most of the cold urticaria patients but negative in patients having other allergic or non-allergic disorders. The chief causes of false positive reactions were a state of atopy and dermographism.

Cold Temperature↗
PubMed1975

Idiopathic acquired cold urticaria in North India.

Forty-three otherwise healthy patients mostly between the ages of 10 and 40 were seen in North India during a two-year period with urticaria which developed on taking a cold water bath, exposure to cold winds, evaporation of rain water or sweat in that order of frequency. There was no familial predisposition to cold urticaria or atopic disorders. The refrigeration test for cryo-proteins was negative. Only one patient developed a wheal on contact with ice but 38 of 43 patients showed an exaggerated erythema response to a cold-pressure test (cryo-stimulation test).

Adolescent↗