Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.1.99.3 (PRE)
 1,923 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cultured cells of placental mammals (including human skin fibroblasts) as well as fresh cornea tissue from oxen have been UV (254 nm)-irradiated and either kept dark or exposed to photoreactivating light (wavelengths greater than 375 nm only) prior to extraction of their DNA. The latter was added to an in vitro photorepair system consisting of UV-irradiated DNA from Haemophilus influenzae and yeast-photoreactiving enzyme, illuminated with broad-spectrum white fluorescent light. The extent of competitive inhibition of the in vitro photorepair of Haemophilus-DNA, resulting from the addition of mammalian DNA, has been taken as a measure of mammalian DNA lesions capable of reacting with photoreactivating enzyme. In most cases the amount of these DNA lesions was reduced if the UV-irradiated mammalian cells had been light-exposed prior to DNA extraction, indicating photoenzymatic repair of up to 90% of the lesions. DNA damage by the photoreactivating light itself was observed at varying degrees in human cells, where this effect presumably masks some of the photorepair.
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PMID:Damage and repair in mammalian cells after exposure to non-ionizing radiations. III. Ultraviolet and visible light irradiation of cells of placental mammals, including humans, and determination of photorepairable damage in vitro. 736 Jan 43

A pharmacokinetic study is described in which Friesian calves (n = 30) were treated orally with clenbuterol at 10 times the therapeutic dose. The study was designed to establish the distribution and elimination of clenbuterol from edible tissues, the major compartments of the eye and body fluids. Animals (n = 24) were dosed (10 micrograms/kg body weight) twice daily with clenbuterol for 21 days and slaughtered in groups of five (one untreated control animal per group) at 6 h and 1, 2, 4, 8 and 16 days after cessation of treatment. At slaughter, samples of diaphragm muscle, liver, kidney, bile, urine and both eyes were obtained. One of the eyes was separated into constituent tissues: aqueous humour, vitreous humour, cornea, lens, retina (without pigmented epithelium), choroid (with pigmented retinal epithelium; choroid/PRE) and sclera. All samples were stored at -20 degrees C. Clenbuterol concentrations were higher in liver than kidney, bile and urine from day 2 of withdrawal onwards. Concentrations in choroid/PRE were at least 10 times higher than in liver at all periods following cessation of treatment and 52 times higher 16 days after treatment. The concentrations of clenbuterol in the constituent tissues of the eye were in the order choroid/PRE > cornea > > retina > aqueous humour/vitreous humour > or = lens. Concentrations of clenbuterol in choroid/PRE taken from eyes frozen whole were generally lower than those in choroid/PRE separated before storage. Choroid/PRE stored by either method contained clenbuterol at more than 100 ng/g 16 days following cessation of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Distribution and elimination of clenbuterol in tissues and fluids of calves following prolonged oral administration at a growth-promoting dose. 762 33