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)

Dermatologic, ophthalmologic, and neurologic examinations were carried out on 33 patients with clinical symptoms of xeroderma pigmentosum (XP). Complementation groups were determined for 23 patients. Types of tumors and complementation group were found to be related in the following way: In the XP variant groups basaliomas were the most frequently occurring malignant tumors, whereas in the D group pigmentary tumors, such as melanotic precanceroses and melanomas prevailed; in the A and the C group, spinaliomas seem to be the most frequent malignomas. The DNA repair activity was measured using colony-forming ability and unscheduled DNA synthesis. Colony-forming ability was quantitated as a function of 12 different UV doses and expressed in terms of D0. Unscheduled DNA synthesis was determined autoradiographically by establishing dose-response curves, which were analyzed by the characteristic value of linear regression. G0, defined as the linear increase in the mean number of silver grains per nucleus when the UV dose is multiplied by the factor of e (i.e., 2.72), was derived from the slopes of the regression lines. The repair capability of XP fibroblast lines was classified on the basis of D0 and G0.
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PMID:Xeroderma pigmentosum patients from Germany: clinical symptoms and DNA repair characteristics. 716 74

Both xeroderma pigmentosum group A (XPA) and Cockayne syndrome (CS) are rare autosomal disorders, have a genetic defect in the step of nucleotide repair, and involve various neurological abnormalities caused by progressive neurodegeneration. We performed comprehensive neuropathological analysis of five cases of XPA and four cases of CS. The XPA cases showed widespread neuronal loss throughout the central nervous system, in sharp contrast to the comparative preservation of neurons in the CS cases, who rather exhibited patchy demyelination in the cerebral and cerebellar white matter, and multifocal calcium deposition in the basal ganglia and cerebral white matter, respectively. Exceptionally in the cerebellar cortex, neuronal loss was more severe in CS than in XPA. Grumose or foamy spheroid bodies occurred in the globus pallidus and substantia nigra, and axonal torpedoes were increased in the cerebellar cortex in both disorders. Neither silver impregnation nor immunohistochemistry for ubiquitin or tau succeeded in visualizing neurofibrillary tangles, senile plaques or augmented ubiquitination in either disorder, and these findings did not support the involvement of facilitated aging in the neurodegeneration in XPA or CS.
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PMID:Neurodegeneration in hereditary nucleotide repair disorders. 1041 20

The alkaline and neutral comet assays have been widely used to assess DNA damage and repair in individual cells after in vivo or in vitro exposure to chemical or physical genotoxins. Cells processed under neutral conditions generate comets primarily from DNA double strand breaks, whereas under alkaline conditions, comets arise from DNA single and double strand breaks and alkali-labile lesions. A modified version of the alkaline comet assay, as described here, used silver stain to visualize the comets and a Gelbond base to facilitate the manipulation and processing of samples. To demonstrate how these modifications improve the assay, fibroblasts derived from both normal and Xeroderma pigmentosum (Xp) individuals were exposed to simulated solar radiation and the resulting DNA damage and repair evaluated and compared with results from the relevant literature. Comets from normal fibroblasts reached their maximum length at about an hour after irradiation. Dose-dependent increases in comet length were observed up to at least 360 mJ/cm2. In contrast, comet lengths from repair deficient Xp fibroblasts were shorter than normal cells reflecting their reduced capacity to generate single strand breaks by the excision of DNA dimers. For incubation times of more than 1 h, comet lengths from normal fibroblasts underwent a time-dependent decrease, supporting the contention that this change was related to the ligation step in the DNA repair process. These changes were compatible with the model of DNA damage and repair established by others for ultraviolet radiation.
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PMID:The use of silver-stained "comets" to visualize DNA damage and repair in normal and Xeroderma pigmentosum fibroblasts after exposure to simulated solar radiation. 1082 92