Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043346 (xeroderma pigmentosum)
 2,924 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The UV induction of diphtheria toxin-resistant (DTr) mutants in normal and xeroderma pigmentosum human fibroblasts has been quantitatively characterized. A concentration of diphtheria toxin at which DTr cells are cross-resistant to Pseudomonas aeruginosa exotoxin A was determined and used in the selection of resistant mutants. Recovery of mutants was not influenced by the presence of wild-type cell densities of 1-8 x 10(5) per 9-cm plate, indicating no metabolic cooperation exists, in contrast to what is seen in the selection of some other variant phenotypes. Expression periods for UV-induced mutations differed with the severity of mutagen treatment and cell strain used. A relatively long (10-15 days after UV treatment) expression period was required for the maximum recovery of DTr mutants. Maximum recovery was followed by a decrease in mutation frequency on subsequent days evaluated. An apparent linear dose response within the dose range used was observed for UV-induced mutations in both normal and xeroderma pigmentosum fibroblasts. Our results indicate that xeroderma pigmentosum fibroblasts have higher UV-induced mutation frequencies per unit UV dose but similar frequencies per unit survival compared to normal cells within the range of UV doses tested.
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PMID:Ultraviolet light induction of diphtheria toxin-resistant mutants of normal and xeroderma pigmentosum human fibroblasts. 29 Oct 58

This study of identical twins affected with xeroderma pigmentosum, with follow-up and re-evaluation after a period of eight years, is unique in that it demonstrates clearly the value of cancer control methods, primarily the avoidance of solar radiation. The findings in the identical twins have been evaluated in context with their other affected siblings who also have shown a remarkable low rate of skin cancer upon initiation of cancer control (solar radiation avoidance).
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PMID:Cancer control in xeroderma pigmentosum. 30 3

A case of xeroderma pigmentosum with associated band-shaped nodular dystrophy of the cornea is discussed. Band-shapped nodular dystrophy of the cornea usually occurs in elderly Bantu men. Band-shaped nodular dystrophy in a young Bantu man suffering from a genetically determined solar sensitive disease lends credence to the possibility that band-shaped nodular dystrophy is a solar sensitive disease, as has so often been postulated.
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PMID:Xeroderma pigmentosum and band-shaped nodular corneal dystrophy. 30 Feb 46

A 6-year-old girl with xeroderma pigmentosum was contact and photocontact sensitized to PABA which had been used as a sunscreening agent. The activating wavelengths for photocontact dermatitis were in long-wave ultraviolet light. The experimental photocontact sensitization was not induced in guinea pigs. Although PABA is the most effective and harmless sunscreening agent for normal skin, it could induce photocontact sensitivity especially in diseased or damaged skin.
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PMID:Photocontact dermatitis from P-aminobenzoic acid. 30 24

Four patients with Xeroderma pigmentosum are reported: 2 diagnosed following the development of multiple cutaneous tumours, and 2 at an earlier state. The repair synthesis of DNA after ultraviolet radiation was reduced in 3 and normal in 1 patients. Para-aminobenzoic acid (PABA) was used topically as sunscreen; for those intolerant to PABA, alternatives are given. 5-fluoro-uracil had satisfactory effect against actinic keratoses. Two patients had associated neurologic and mental abnormalities compatible with deSanctis-Cacchione syndrome, a Xeroderma pigmentosum variant.
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PMID:Xeroderma pigmentosum--biochemical and therapeutic aspects. Case report. 30 15

Xeroderma pigmentosum is a recessive autosomal disease of humans that is characterized by a high prevalence of skin cancers. Results of studies on cells from such patients indicate a defect in the repair of DNA damage associated with exposure to ultraviolet radiation. Since this observation was reported, a large amount of information on this disease has accumulated in the literature.
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PMID:Xeroderma pigmentosum: recent studies on the DNA repair defects. 33 72

Under the specific conditions reported for the separate tests delta9-tetrahydrocannabinol (THC) did not elicit a mutagenic response in microbial and eukaryotic in vitro test systems. THC treatment to histidine auxotrophs of Salmonella typhimurium strains TA 98 (susceptible to frame shift mutation) and TA 100 (susceptible to base pair substitution) were investigated. Analysis for possible revertance in the presence and absence of S9 microsomal activation system indicated an absence of induction of gene mutation. Cultured fibroblasts from healthy individuals and DNA repair deficient Xeroderma pigmentosum patients display similar survival activity upon exposure to THC. There was no observable increase in the number of chromosome breaks or chromatid exchanges following exposure to THC or THC plus S9 microsomal fraction. THC, 11-OHdelta9-THC, cannabinol, and cannabidiol did not induce unscheduled DNA repair synthesis in cultured human fibroblasts. Moreover, THC did not suppress UV-induced DNA repair synthesis.
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PMID:Nonmutagenic action of cannabinoids in vitro. 35 30

Liquid-holding conditions can be obtained for human diploid skin fibroblasts by keeping confluent cultures stationary over periods of 7 days or longer by means of conditioned medium. Under this condition recovery of radiation damage induced by ultraviolet light or X-rays is observed as an increase in cloning efficiency. The amount of recovery when expressed in a dose-modifying-factor appears higher than in bacteria and yeast. The repair-deficient human cell strains XP25Ro and XP7Be (xeroderma pigmentosum from complementation groups A and D respectively) exhibit less but still discernible recovery after UV-irradiation and the same was observed for AT5Bi (ataxia telangiectasia) after X-irradiation. Experiments on mutation induction indicated that the repair which takes place during liquid holding of UV-irradiated XP7Be cells reduces the mutant frequency considerably while after liquid holding of UV-irradiated wild-type cells the same or lower mutant frequencies were found for the lower exposures and the same or higher mutant frequencies for the higher exposures.
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PMID:Development of a liquid-holding technique for the study of DNA-repair in human diploid fibroblasts. 37 75

The sensitivity of cultured fibroblasts obtained from four unrelated Xeroderma pigmentosum patients (XP-K, XP-C, XP-E and XP-H), which showed different DNA repair levels, was examined. The frequency of metaphase plates with chromosome aberrations and the frequency of breaks and exchanges per chromosome complement were estimated following exposure to the carcinogens 4-nitroquinoline-1-oxide (4NQO),N-acetoxy-2-acetyl-aminofluorene (N-acetoxy-2-AAF), and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and to the mutagen daunomycin. The frequency of chromosome aberrations (breaks and exchanges) increased in the order (XP-K less than XP-C less than XP-E less than XP-H) with decreasing DNA repair capacity of the XP cells examined (XP-K greater than XP-C greater than XP-E greater than XP-H) following 4NQO and N-acetoxy-2-AAF. MNNG induced DNA repair synthesis and chromosome aberrations in the four XP cell types at levels comparable to those in fibroblasts of non-afflicted persons. Daunomycin triggered no DNA repair synthesis but induced similar frequencies of chromosome aberrations in the XP cells and controls. Heterozygous XP cells from parents of XP-K, XP-E and XP-C responded as control cells towards the three carcinogens and the mutagen used. Xeroderma pigmentosum can be considered to be an "induced" chromosome instability syndrome, in contrast to Bloom's syndrome or Fanconi's anaemia, which are "spontaneous" chromosome breakage syndromes according to German's definition.
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PMID:Differential sensitivity of Xeroderma pigmentosum cells of different repair capacities towards the chromosome breaking action of carcinogens and mutagens. 40 78

The cytotoxic action of physical and chemical agents on 10 skin fibroblast strains in culture derived from individuals with Cockayne's syndrome was measured in terms of colony-forming ability. As compared to fibroblasts from normal donors, all Cockayne cell strains tested exhibited a significantly increased sensitivity to UV light and a normal sensitivity to X-rays. Cells from two sets of parents of unrelated Cockayne children showed an intermediate level of UV sensitivity. There was no effect of 0.5 mM caffeine on UV survival in normal and two Cockayne strains tested, indicating that postreplicational repair in Cockayne cells as measured by caffeine sensitivity was probably normal. Sensitivity of normal and Cockayne cells to the chemical carcinogens and mutagens 4NQO, N-AcO-AAF, ICR-170 and EMS was also compared. An increased sensitivity of Cockayne cells to 4NQO or N-AcO-AAF, but not the ICR-170 or EMS, was observed. However, unlike the intermediate UV sensitivity, the cell strains from two parents of Cockayne patients showed the same sensitivity to N-AcO-AAF or 4NQO as fibroblasts from normal individuals. Quantiation of damage to the DNA after 20 J . m-2 UV irradiation indicates normal levels of [3H] thymidine incorporation in the Cockayne cells, in contrast to UV-irradiated xeroderma pigmentosum cells (XP 12BE) in which there was a very low level of repari synthesis. Moreover, we have shown previously that excision of UV-induced pyrimidine dimers in 2 of the 10 Cockayne cell strains was normal.
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PMID:Effects of DNA damaging agents on cultured fibroblasts derived from patients with Cockayne syndrome. 43 51


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