Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004135 (ATM)
 13,001 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immune status of 22 patients of ataxia telangiectasia was studied over a period of 8 yr (mean age of patients: 9.5 +/- 3 yr; 9 of 22 were siblings). Low T-cell number was observed in 14 of 19 patients but the response to PHA challenge done in 10 patients was normal and migration inhibition to BCG antigen was positive in 6 of 6 patients. IgM defect was seen in 2 out of 18 patients and serum IgA was deficient in 10 out of 18 patients. Salivary IgA was also absent in these children. Four children had high spontaneous NBT reduction. None of the patients had lymphoma, leukemia or any other malignancy at the time of presentation. Candida killing was normal in all patients. The presenting feature related to the CNS in almost all children and gross infections were not seen.
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PMID:Immune status in ataxia telangiectasia. 193 11

Ataxia-telangiectasia is a genetic syndrome with progressive cerebellar ataxia, oculocutaneous telangiectasias and other skin manifestations, variable immune system defects, chronic progressive sinopulmonary disease, and a high incidence of cancer. Cutaneous granulomas developed and persisted in eight patients with ataxia-telangiectasia, despite treatment with intravenously administered immune globulin, topical antibiotic therapy, and potent topical corticosteroid therapy. We were unable to identify an infectious agent; the granulomas may develop in an attempt to localize antigen in the presence of a dysfunctional immune system.
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PMID:Cutaneous granulomatous lesions in patients with ataxia-telangiectasia. 196 Jun 7

The leukemic cells and derivative cell line from a 74-year-old male with T-cell acute lymphoblastic leukemia showed chromosomal abnormalities including a t(14;14)(q11.2;q32). This translocation is characteristic of a variety of T-cell malignancies, particularly T-cell prolymphocytic leukemia and the clonal proliferations of peripheral T cells in patients with ataxia-telangiectasia. Using DNA probes that spanned the T-cell receptor alpha chain (TCRA) joining (J) locus, the DNA rearrangement caused by the translocation was identified, cloned, and sequenced. The breakpoint shows site-specific juxtaposition of a TCRA joining segment and DNA from a region of 14q32 centromeric to the immunoglobulin heavy chain locus. Comparison of restriction map and nucleotide sequence from this translocation with other related chromosomal breakpoints suggests a dispersion of breakpoints throughout the 14q32 region.
Cancer Genet Cytogenet 1990 Jan
PMID:Characterization of the breakpoint of a t(14;14)(q11.2;q32) from the leukemic cells of a patient with T-cell acute lymphoblastic leukemia. 196 57

The contribution of DNA damage to the effects of 193-nm excimer laser radiation on mammalian cells in culture was studied in order to evaluate the mutagenic potential of this UV wavelength in vivo. Two approaches were taken: measurement of pyrimidine dimer-specific endonuclease-sensitive sites/megabase and comparison of the 193-nm radiation-induced cytotoxicity in normal versus DNA repair-deficient cells. The formation of pyrimidine dimer-specific endonuclease-sensitive sites/megabase was inversely related to the thickness of the cytoplasm overlying the nuclei of normal human fibroblasts (NHF) and Chinese hamster ovary cells. The results of these measurements and a calculation of the absorption coefficient of cytoplasm indicate that each 1 micron of cytoplasm attenuates the incident radiation by greater than 90% and, therefore, the nuclear DNA in tissue will be highly protected from 193-nm radiation by overlying cytoplasm. The reduction in colony-forming ability induced by 254-nm, 193-nm, and X-ray radiation was measured in NHF, xeroderma pigmentosum (group A) cells, and ataxia telangiectasia cells. Xeroderma pigmentosum (group A) cells were 16.5 times more sensitive to 254-nm radiation but only 3.5 times more sensitive to 193-nm radiation than NHF cells, indicating that cyclobutylpyrimidine dimers were not the major lethal lesion formed at 193 nm. AT cells were 3.4 times more sensitive to X-rays than NHF cells, but these cell types were almost equally sensitive to 193-nm radiation, indicating that 193 nm did not induce the same type of lethal lesions as X-rays.
Cancer Res 1991 Jan 01
PMID:DNA damage induced by 193-nm radiation in mammalian cells. 198 91

Cultured fibroblast cells from 19 patients with non-Hodgkin's lymphoma (NHL), 3 patients with ataxia telangiectasia (AT), 3 AT heterozygotes and 11 (presumed) normal subjects were studied for impaired colony-forming ability after chronic gamma irradiation. Five cell lines from the NHL patients were also examined for the sensitivity to acute gamma irradiation, as compared with those of normal subjects. To ascertain the degree of radiosensitivity of different cell lines, a comparison was made of the D10 values (radiation dose resulting in 10% survival) for each cell line, estimated "by eye" from the actual survival curves, and also from the calculated curves fitted to a log-linear model. It was observed that the acute gamma irradiation failed to show any appreciable difference in the radiation response of the cell lines from NHL patients as compared with those of normal subjects. However, chronic irradiation demonstrated significantly increased radiosensitivity in at least 10-12 NHL patients with a p value of less than 0.05, when the D10 values of each patient's cell line were compared with the calculated composite values for the normals. When the D10 values of the NHL patients and the normal subjects were compared as 2 groups, the former appeared to be significantly more sensitive to chronic gamma irradiation (p less than 0.0001). The same level of significant difference in radiosensitivity was found between the 2 groups when their D37 values (radiation dose resulting in 37% survival) were compared. In general, the radiation response of the NHL patients was similar to that of the AT homozygotes and heterozygotes used as a positive control group. Our data thus show that increased radiosensitivity is associated with the NHL patients studied, indicating an underlying abnormality of their DNA repair.
Int J Cancer 1991 Jan 21
PMID:Skin fibroblast cell lines derived from non-Hodgkin's-lymphoma (NHL) patients show increased sensitivity to chronic gamma irradiation. 198 69

The effect of ionizing radiation on the expression of two DNA-damage-inducible genes, designated gadd45 and gadd153, was examined in cultured human cells. These genes have previously been shown to be strongly and coordinately induced by UV radiation and alkylating agents in human and hamster cells. We found that the gadd45 but not the gadd153 gene is strongly induced by X rays in human cells. The level of gadd45 mRNA increased rapidly after X rays at doses as low as 2 Gy. After 20 Gy of X rays, gadd45 induction, as measured by increased amounts of mRNA, was similar to that produced by the most effective dose of the alkylating agent methyl methanesulfonate. No induction was seen after treatment of either human or hamster cells with 12-O-tetradecanoylphorbol-13-acetate, a known activator of protein kinase C (PKC). Therefore, gadd45 represents the only known mammalian X-ray-responsive gene whose induction is not mediated by PKC. However, induction was blocked by the protein kinase inhibitor H7, indicating that induction is mediated by some other kinase(s). Sequence analysis of human and hamster cDNA clones demonstrated that this gene has been highly conserved and encodes a novel 165-amino-acid polypeptide which is 96% identical in the two species. This gene was localized to the short arm of human chromosome 1 between p12 and p34. When induction in lymphoblast lines from four normal individuals was compared with that in lines from four patients with ataxia telangiectasia, induction by X rays of gadd45 mRNA was less in the cell lines from this cancer-prone radiosensitive disorder. Our results provide evidence for the existence of an X-ray stress response in human cells which is independent of PKC and which is abnormal in taxia telangiectasia.
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PMID:Induction by ionizing radiation of the gadd45 gene in cultured human cells: lack of mediation by protein kinase C. 199 Feb 62

Ataxia-telangiectasia is a syndrome with many facets, involving a progressive cerebellar ataxia, immunodeficiency, cancer susceptibility, radiosensitivity, defects in DNA repair/processing, chromosomal breakage and rearrangements, elevated serum alphafetoprotein, and premature aging. Ataxia-telangiectasia is an autosomal recessive disorder, rare in outbred populations; carriers of the ataxia-telangiectasia gene may be as common as 1 in 60 and have subclinical radiosensitivity and cancer susceptibility. One estimate suggests that 8.8% of patients with breast cancer could be carriers of ataxia-telangiectasia. These carriers may be responsible for underestimating normal tolerance doses for radiation therapy by 15% to 20%; thus by preselecting and excluding carriers of ataxia-telangiectasia from cohorts of patients with cancer, conventional radiation doses might be increased so as to improve greatly the efficacy of radiotherapy. The genes for the 3 most common ataxia-telangiectasia complementation groups, which include 97% of tested families, have recently been localized to the long arm of chromosome 11.
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PMID:Ataxia-telangiectasia: an interdisciplinary approach to pathogenesis. 200 80

Ataxia telangiectasia (AT) is a primary immunodeficiency syndrome characterized by cerebellar ataxia, extrapyramidal signs, oculocutaneous telangiectasia, recurrent respiratory infections and development of malignancies. AT is a complex autosomal recessive disorder involving several systems other than lymphoid cells or the central nervous system. Such a diversity of abnormalities includes hypersensitivity of fibroblasts and lymphocytes to ionizing radiation (anomaly of DNA repair), non-random chromosomal rearrangements in lymphocytes, elevated serum level of alpha-fetoprotein, premature aging and endocrine disorders. A DNA processing or repair protein is the suspected common denominator in this pathology. Whatever the putative common underlying mechanism, AT patients have profound alterations of the humoral and cellular immune system whose mechanisms should be discussed in terms similar to those for other immunodeficiency diseases. The usual immunological abnormalities in this disease include decreased levels of CD 3 and CD 4 positive T lymphocytes, impaired delayed hypersensitivity, hypoplasia of thymus, decreased blast transformation in vitro in response to mitogen or antigenic stimulation, and decreased levels of serum IgA, IgE, and IgG 2 subclass. In this paper, the results of our recent studies on the defects of B cells in patients with AT were presented. (1) We found that the geometric means of IgA production in the supernatants of the lymphoblastoid cell lines established by EB virus, from all patients with AT, were significantly lower than those from healthy controls (P less than 0.01). (2) IgG subclasses of the patients' sera were also measured by ELISA, and IgG 4 was defective in four cases among six patients with AT.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Ataxia telangiectasia and characterization of its immunological disorders]. 215 3

Ataxia-telangiectasia and xeroderma pigmentosum are human hereditary diseases in which patients are cancer prone and demonstrate increased sensitivity to DNA damage by ionizing and ultraviolet radiation, respectively. In culture, both ataxia-telangiectasia and xeroderma pigmentosum skin fibroblasts show increased synthesis and secretion of the extracellular matrix proteins fibronectin and collagen. To determine whether these differences in protein production result from fundamental abnormalities in regulation of genes associated with cellular interactions, we compared the effects of trifluoperazine and 12-O-tetradecanoylphorbol-13-acetate on expression of the extracellular matrix-degrading metalloproteinases, procollagenase and prostromelysin, by normal, ataxia-telangiectasia, and xeroderma pigmentosum fibroblasts. After trifluoperazine treatment the overall levels of these metalloproteinases were much greater in three ataxia-telangiectasia cell strains and in cells from xeroderma pigmentosum complementation groups A and D than in normal cells. In contrast, cells from xeroderma pigmentosum complementation group C produced only slightly more procollagenase than normal cells. 12-O-tetradecanoylphorbol-13-acetate also induced higher than normal levels of procollagenase in some ataxia-telangiectasia and xeroderma pigmentosum strains, but less than that induced by trifluoperazine. Because increased extracellular accumulation of matrix-degrading enzymes has long been implicated in metastatic progression, this altered expression of procollagenase and prostromelysin in ataxia-telangiectasia and xeroderma pigmentosum cells could play an important role in the pathogenesis of various tumors in individuals with these genetic diseases.
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PMID:Enhanced expression of procollagenase in ataxia-telangiectasia and xeroderma pigmentosum fibroblasts. 217 6

Ataxia-telangiectasia (A-T) is a progressive neurologic disorder in which there is varied immune dysfunction, an excess sensitivity to ionizing radiation, and a striking predisposition to cancer. It is the autosomal recessive syndrome for which there is the strongest evidence, derived from retrospective studies of cancer incidence and mortality in A-T families, that the heterozygote is predisposed to cancer. We present, in tabular form, the specific cancer sites or types most likely to be associated with A-T heterozygosity. These include solid tumors of the breast, pancreas, stomach, bladder, and ovary, and chronic lymphocytic leukemia. We also introduce a new method to test these associations. As soon as molecular probes for the A-T allele(s) are available, this new research design will be used to test rigorously each association, hypothesized on the basis of previous data, between a specific cancer site and A-T heterozygosity.
Cancer Genet Cytogenet 1990 May
PMID:Cancer predisposition of ataxia-telangiectasia heterozygotes. 218 33


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