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Query: UMLS:C0004135 (ATM)
 13,001 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this paper, using polymerase chain reaction (PCR), we demonstrated the occurrence of hybrid genes formed by interlocus recombination between T cell receptor gamma (TCR-gamma) variable (V) regions and TCR-beta joining (J) regions in the peripheral blood lymphocytes (PBL) from normal individuals and patients with ataxia-telangiectasia (AT). Sequence analysis of the PCR-derived hybrid genes confirmed that site-specific V gamma-J beta recombination had occurred and showed that 10 of 23 genomic hybrid genes maintained a correct open reading frame. By dilution analysis, the frequency of these hybrid genes was 8 +/- 1/10(5) cells in normal PBL and 587 +/- 195/10(5) cells in AT PBL. These frequencies and the approximately 70-fold difference between the normal and AT samples are consistent with previous cytogenetic data examining the occurrence of an inversion of chromosome 7 in normal and AT PBL. We also demonstrated expression of these hybrid genes by PCR analysis of first-strand cDNA prepared from both normal and AT PBL. Sequence analysis of the PCR-amplified transcripts showed that, in contrast to the genomic hybrid genes, 19 of 22 expressed genes maintained a correct open reading frame at the V-J junction and correctly spliced the hybrid V-J exon to a TCR-beta constant region, thus allowing translation into a potentially functional hybrid TCR protein. Another type of hybrid TCR transcript was found in a which a rearranged TCR-gamma V-J exon was correctly spliced to a TCR-beta constant region. This form of hybrid gene may be formed by trans-splicing. These hybrid TCR genes may serve to increase the repertoire of the immune response. In addition, studies of their mechanism of formation and its misregulation in AT may provide insight into the nature of the chromosomal instability syndrome associated with AT. The mechanism underlying hybrid gene formation may be analogous to the mechanism underlying rearrangements between putative growth-affecting genes and the antigen receptor loci, which are associated with AT lymphocyte clones and lymphoid malignancies.
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PMID:Hybrid T cell receptor genes formed by interlocus recombination in normal and ataxia-telangiectasis lymphocytes. 169 65

Immunofluorescent flow cytometric examination of one hundred and eighty-five children with different primary immunodeficiency syndromes and sixty-nine control patients revealed twenty-six cases with a bimodal distribution of antigens CD5 and CD7. Such abnormalities were most frequently found in patients with total antibody deficiency, namely those with common variable hypogammaglobulinaemia (10/24 patients) and congenital agammaglobulinaemia with lack of B cells (10/40), but were never seen in normal controls. Two-colour flow immunofluorescence demonstrated that antigen CD4 was expressed only on intensely fluorescent CD5+ cells, irrespective of the immunodeficiency state. Antigen CD4 was detected on cells with both high and low expression of antigen CD7, but a small percentage (2%-5%) of CD4+ lymphocytes did not belong to the CD7+ population. Antigen CD8 was found equally on intensely and weakly fluorescent CD5+ and CD7+ cells. In some immunodeficient patients suffering from ataxia-telangiectasia (12/36) and in some with Wiskott-Aldrich syndrome (2/6) there was a significant excess (greater than 20%) of CD7+ over CD5+ cells. In these patients a considerable number of the CD8+ cells were not part of the CD5+ population, but were always part of the CD7+ population. Cell populations with the phenotype CD5-, CD7+ consisted mainly of lymphocytes showing weak expression of antigen CD8.
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PMID:Two-colour flow cytometry study of lymphocyte subpopulations in patients with primary immunodeficiencies. 171 14

It is the purpose of this review to analyse prevalence and pathogenesis of tumours occurring in the diverse conditions of primary and secondary immunodeficiencies. In general, most states of immunodeficiences are connected with a highly increased tumour risk. However, there is circumstantial evidence that immunodeficiency-related malignancies do not primarily result from an impaired immunosurveillance. With special regard to ataxia-telangiectasia it has been found that congenital chromosomal instability deregulates the maturation of immunocompetent lymphoid cells by interfering with their natural DNA rearrangements and eventually leads to false recombinatory events with oncogenetic consequences in a parallel way. Malignancies in primary common variable or in secondary (e.g. AIDS) immunodeficiency may result from an impaired immunity to oncogenic viruses or from chronic immune damage due to secondary autoimmune disorders.
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PMID:[Tumors in immunodeficiency syndromes]. 172 56

We report the occurrence of a leiomyoma of the suprarenal gland in a 10-year-old girl with ataxia-telangiectasia (A-T). Muscle cell tumors are very uncommon in this gland as they are in A-T. Possible reasons for developing nonhematologic tumors in this syndrome are reviewed. A defect in DNA repair mechanisms probably favors, in young children, the expression of tumors normally expected in the aged.
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PMID:Leiomyoma of the suprarenal gland in a child with ataxia-telangiectasia. 174 82

Linkage of at least two complementation groups of ataxia-telangiectasia (AT) to the chromosomal region 11q23 is now well established. We provide here an 18-point map of the surrounding genomic region, derived from linkage analysis of 40 CEPH families. On the basis of this map, 111 AT families from Turkey, Israel, England, Italy, and the United States were analyzed, localizing the AT gene(s) to an 8-cM sex-averaged interval between the markers STMY and D11S132/NCAM. A new Monte Carlo method for computing approximate location scores estimates this location as being at least 10(8) times more likely than the next most likely interval, with a support interval midway between STMY and D11S132 that is either 5.2 cM (sex-averaged and conservatively based on 3 lod scores from the maximum-location score) or 2.8 cM (male specific, based on a 2.72:1 interval-specific female-to-male distance ratio.
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PMID:Localization of an ataxia-telangiectasia locus to a 3-cM interval on chromosome 11q23: linkage analysis of 111 families by an international consortium. 159 15

Tumors of the female genital tract may be associated with a variety of unusual clinical manifestations. Uncommon endocrine and paraendocrine syndromes include production of human chorionic gonadotropin by tumors other than those of germ cell origin, hyperthyroidism associated with struma ovarii and gestational trophoblastic disease, the carcinoid syndrome, the Zollinger-Ellison syndrome, hypercalcemia, Cushing's syndrome, hypoglycemia, hypertension related to renin or aldosterone production, hyperprolactinemia, inappropriate secretion of antidiuretic hormone, and virilization associated with Nelson's syndrome and placental site trophoblastic tumor. Paraneoplastic syndromes associated with gynecological tumors include disorders of the nervous system, connective tissue, and skin, as well as hematologic abnormalities and the nephrotic syndrome. Heritable and other congenital syndromes associated with these tumors are the Peutz-Jeghers syndrome, the nevoid basal-cell carcinoma syndrome, Ollier's disease and Maffucci's syndrome, hereditary leiomyomatosis, ataxia-telangiectasia, von Hippel-Lindau's disease, thyroid abnormalities associated with Sertoli-Leydig cell tumors, and Carney's complex. Other syndromes associated with tumors of the female genital tract include Meigs' syndrome, hyperamylasemia, uveal melanocytic lesions, and pyrexia.
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PMID:Clinical syndromes associated with tumors of the female genital tract. 175 57

The clinical and immunological findings of 160 patients diagnosed over a period of twenty years as having ataxia-telangiectasia (AT) are presented. The study group composed of 68 females and 92 males were members of 117 families. The rate of parental consanguinity was 65 percent. The incidence of AT in 117 families was 36.6 percent. All patients had the characteristic facial and postural features of AT. The mean duration of follow-up of 160 patients was 6.35 years. Fifty patients had died during the follow-up (36 of pulmonary infections, 14 of malignancies). Somatic growth retardation was a prominent feature. Recurrent sinopulmonary infections were detected in 66 percent of patients. Two patients had hypothyroidism, one had diabetes mellitus, and one had both conditions. The incidence of malignancies was found to be 2.3 percent in the immediate relatives of the patients. The total lymphocyte count was low in 57 percent, and skin tests to PHA, candida, PPD and SK-SD were negative in 17.7%, 72.6%, 43.6%, and 78.2% of patients, respectively. In vitro blastogenic response to PHA was low in 61 percent of patients. The mean value of E-rosette formation was significantly lower than control values. Six patients had low serum IgG levels. The serum IgM level was high in 26.6 percent of patients and the IgA level was low or absent in 51.3 percent. There was no correlation between immune disturbance and duration of illness.
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PMID:Twenty-year follow-up of 160 patients with ataxia-telangiectasia. 181 37

It has been found that irradiation in doses 0.5-2.0 Gy does not enhance the frequency of sister chromatid exchanges in cells of patients with Down's syndrome and ataxia-telangiectasia compared to the normal cells. In the case of ataxia, this phenomenon was accompanied with radioresistant replicative DNA synthesis, whereas in two cases of Down's syndrome the replicative DNA synthesis was found to be as radiosensitive as in the norm. According to these data, the mechanism of sister chromatid exchanges proposed in our previous publication (Pleskach et al., 1988) seems to be rather doubtful.
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PMID:[The relationship between the radiosensitivity of DNA replicative synthesis and the formation of sister chromatid exchanges]. 183 42

We describe the application of a flow cytometric technique for assessing the radiation or drug sensitivity characteristics of human tumour cells. The technique makes use of the phenomenon that a red shift occurs in the fluorescence emission spectrum of a DNA-specific dye (Hoechst 33,342) as an increasing number of dye molecules bind to nuclear DNA. Intact, viable cells undergo a time-dependent spectral shift that can be distinguished from the rapid shift observed in cells with damaged membranes by the use of multiparametric flow cytometry. The responses of various human cell lines were compared, namely, those of normal and ataxia-telangiectasia (A-T) lymphoblastoid lines, a small-cell lung carcinoma line and its (in vitro) derived multidrug-resistant variants. A close correlation was found between dye toxicity and the degree of DNA binding of Hoechst 33,342 independent of cellular DNA content, with lymphoblastoid and multidrug-resistant small-cell lung cancer cells showing enhanced and restricted dye-binding rates, respectively. VP16- and radiation-induced cell kill was found to result in a quantifiable increase in the fraction of cells undergoing a rapid spectral shift and was capable of detecting the increased radiation sensitivity of A-T-derived cells. Spectral shift analysis provides a rapid method for assessing the responses of tumour cells to cytotoxic agents and for determining the general ability of cells to protect cellular DNA from a model DNA-binding agent (Hoechst 33,342) that participates in the multidrug resistance phenotype.
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PMID:Detection of multidrug resistance and quantification of responses of human tumour cells to cytotoxic agents using flow cytometric spectral shift analysis of Hoechst 33,342-DNA fluorescence. 184 64

The expression of both the Epstein-Barr virus (EBV) ORF BHRF1 and the cellular protooncogene bcl-2 was studied in EBV-transformed lymphoblastoid B cells from patients with the human genetic disorder ataxia-telangiectasia (A-T). Using the Northern blot technique, it was found that the pattern of transcription of the BHRF1 gene in A-T lymphoblastoids resembled that in EBV-transformed normal lymphoblastoid lines and Burkitt lymphoma (BL) lymphocytes. However, the 1.5-kb mature BHRF1 mRNA species present in normal lymphoblastoid cells and in BL cells was not found in the A-T lymphoblastoid cell lines. Treatment of the A-T lymphoblastoid lines with phorbol ester caused changes in the pattern of the synthesis and quantity of BHRF1-related RNA transcripts. The bcl-2 protooncogene probe did not detect bcl-2-related mRNA in the A-T lymphoblastoid lines.
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PMID:Epstein-Barr virus BHRF1 gene but not the cellular protooncogene bcl-2 is expressed in ataxia-telangiectasia lymphoblastoid lines. 185 Jan 86


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