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Biomedical subjects

B Ljunggren

Publications and source records attributed to B Ljunggren.

At least 163 records · Page 9Linked to original sources
PubMed1978

Inhibition of ultraviolet and phototoxic dermatitis in the mouse.

The effect of inhibitors on the inflammatory oedema elicited by medium-wave ultraviolet radiation (UVB) and long-wave ultraviolet radiation (UVA) in combination with chlorpromazine has been studied in the mouse, by means of a quantitative technique. Inhibition of the UVB reaction was observed with indomethacin, acetylsalicylic acid and betamethasone valerate, whereas the latter compound only was effective in the phototoxic state. No inhibition was obtained with hydrocortisone, phenylbutazone, epsilon-aminocaproic acid, polyphloretin phosphate, clemastin, alpha-tocopherol or ascorbic acid. With indomethacin and betamethasone valerate there was no inhibition at high doses when the compound was administered before UVB irradiation. These results are in accordance with a proposed central role for the prostaglandins in UVB inflammation. It is suggested that the phototoxic reaction to chlorpromazine may not be due to mediator action but rather to the effect of toxic photoproducts.

Animals↗
PubMed1977

Phenothiazine phototoxicity: an experimental study on chlorpromazine and its metabolites.

Chlorpromazine (CPZ) metabolites were studied for their phototoxic potency with the mouse tail technique. The demethylated metabolites were more phototoxic potency with the mouse tail technique. The demethylated metabolites were more phototoxic than CPZ, while CPZ-sulfoxide, 7-hydroxy-CPZ, and 2-chlorphenothiazine were less phototoxic. The phototoxicity of CPZ and desmethyl-CPZ preexposed to UVA was lost, while that of CPZ-sulfoxide was retained. By thin-layer chromatography, CPZ-sulfoxide and promazine were identified as photoproducts of CPZ; the sulfoxide was fairly stable to radiation.

Animals↗
PubMed1977

Phenothiazine phototoxicity: toxic chlorpromazine photoproducts.

The effect of preirradiated chlorpromazine (CPZ) solutions has been studied in vivo in the guinea pig and in vitro in a yeast culture. With intracutaneous administration of CPZ solutions preirradiated with long-wave ultraviolet radiation (UVA), an inflammatory response was attained equaling the response achieved when nonirradiated solutions were injected and the skin of the animals was subsequently irradiated with UVA. Preirradiated CPZ was not toxic to the yeast culture. During irradiation the pH of the CPZ solution changed, indicating an accumulation of acid photoproducts. Nonphototoxic phenothiazines and related tricyclic drugs failed to change their pH following irradiation whereas phototoxic compounds behaved like CPZ. The low pH alone could not account for the inflammatory response in vivo, as neutralized irradiated CPZ solutions still induced inflammation, and acidified, nonirradiated solutions failed to cause a reaction. CPZ phototoxicity seems mainly to be due to the effect of photoproducts. The nature of these is not known, but it is suggested that the stable free radical of CPZ might be an active principle.

Animals↗
PubMed1977

Psoralen photoallergy caused by plant contact.

A case of acquired photocontact allergy to furocumarins in plants is reported. Photopatch testing was performed with four psoralens [8-methoxypsoralen (8-MOP), 5-methoxypsoralens (5-MOP), trimethylpsoralen (TMP) and imperatorin (IMP)[. The use of serial dilutions of the test compounds made it possible to differentiate between photoallergic and phototoxic reactions. 8-MOP gave a positive eczematous test reaction down to a concentration of 0.0001%. The reactions to 5-MOP and imp also were positive, while that to TMP awas negative. Histopathological examination of a biopsy specimen from a positive test site showed changes consistent with photoallergic contact dermatitis. The multiple reactions could be explained on the basis of multiple sensitization but cross reactions cannot be ruled out.

Coumarins↗
PubMed1977

Phenothiazine phototoxicity: an experimental study on chlorpromazine and related tricyclic drugs.

A large number of phenothiazines and chemically related tricyclic drugs have been studied with respect to their phototoxic potency. Two methods were used, an in vivo technique based on the inflammatory response of the mouse tail after systemic administration of the drug plus UVA irradiation, and an in vitro method based on growth inhibition of Candida albicans. Of 27 commercial tricyclic drugs tested in vivo, the most potent were chlorpromazine and two other chlorinated compounds, prochlorperazine and perphenazine. Tricyclic drugs lacking nitrogen, sulphur, or both in their ring system showed no activity. All compounds phototoxic in the mouse were so in the yeast test as well. Here, however, the thioxanthenes (lacking nitrogen) were also highly active.

Animals↗
PubMed1976

Phototoxic reaction to chlorpromazine as studied with the quantitative mouse tail technique.

A quantitative in vivo technique for the study of the phototoxic reaction to systemic chlorpromazine has been developed, based on the increasing tissue fluid content of the albino mouse tail. A maximum increase in tissue fluid of about 25% was registered 24 hours after starting the long-wave ultraviolet light exposure. The minimum phototoxic dose of chlorpromazine was 2.5 mg/kg.

Animals↗