ABSTRACT
Photolyase is an enzyme that uses light to catalyze DNA repair. To capture the reaction intermediates involved in the enzyme's catalytic cycle, we conducted a time-resolved crystallography experiment. We found that photolyase traps the excited state of the active cofactor, flavin adenine dinucleotide (FAD), in a highly bent geometry. This excited state performs electron transfer to damaged DNA, inducing repair. We show that the repair reaction, which involves the lysis of two covalent bonds, occurs through a single-bond intermediate. The transformation of the substrate into product crowds the active site and disrupts hydrogen bonds with the enzyme, resulting in stepwise product release, with the 3' thymine ejected first, followed by the 5' base.
Subject(s)
Deoxyribodipyrimidine Photo-Lyase , Crystallography , Deoxyribodipyrimidine Photo-Lyase/chemistry , Deoxyribodipyrimidine Photo-Lyase/metabolism , DNA Repair , DNA Damage , Electron TransportABSTRACT
An assessment was made in healthy skin of dithranol erythema caused by a 10-min occlusive application of 0.5% dithranol (CAS 1143-38-0) in liposomal gel (Natipide II) with and without the addition of 3% salicylic acid, and of 0.5% dithranol in vaseline and in a removable standard ointment base, both with 3% salicylic acid. Both liposomal preparations led to a significant potentiation of the dithranol erythema. The results indicate a strong promotion of the penetration of dithranol by the liposomal gel.
Subject(s)
Anthralin/pharmacology , Anthralin/pharmacokinetics , Adult , Colorimetry , Drug Carriers , Erythema/chemically induced , Female , Humans , Liposomes , Male , Petrolatum , Skin AbsorptionABSTRACT
The case of a 78-year-old woman with a 2-year history of chronic persistent oral candidiasis, in whom an HIV infection (stage III, Frankfurt Classification according to Brodt, stage 6 Walter Reed Staging Classification, stage IV WHO Classification, manifest AIDS according to the new 1988 Classification) was diagnosed, is reported. The 44-year-old son (since deceased) of the patient was known to have had the acquired immune deficiency syndrome since December, 1986. Transmission of HIV from son to mother seems likely.
Subject(s)
Acquired Immunodeficiency Syndrome/transmission , Home Nursing , Acquired Immunodeficiency Syndrome/diagnosis , Adult , Aged , Female , Humans , Male , Risk FactorsABSTRACT
The following study is based on the evaluation of 116 expert opinions obtained between 1984 and 1987 regarding patients working as hairdressers and suffering from eczemas. The most frequent allergen was nickel sulfate (57.7%). Exclusive nickel allergy without sensitization to substances professionally used, however, was only found in 6.9% of the female patients tested. Nickel allergy associated with sensitization to such substances was observed in 50.5% of the patients. 90 out of the 116 persons tested showed positive reactions to the indicator substance used in the hairdressers' trade and/or to the substances actually used during their work. Exclusive sensitization to one or more substances of the indicator group (occupationally used substances negative) was found in 13.3% of the patients; exclusive sensitization to substances actually used (indicator group negative) was seen in 16.7%.
Subject(s)
Dermatitis, Occupational/etiology , Expert Testimony/legislation & jurisprudence , Hair Preparations/adverse effects , Hand Dermatoses/etiology , Workers' Compensation/legislation & jurisprudence , Adult , Dermatitis, Contact/etiology , Female , Hair Dyes/adverse effects , Humans , Intradermal Tests , Male , Nickel/adverse effects , Patch TestsABSTRACT
In addition to the main flavonol glycoside spiraeoside in bulbs of ALLIUM CEPA L., kaempferol-4'-glucoside ( 1) has been found in smaller amounts. Traces of other flavonoids could be detected also.
