Biomedical subjects

T Quertermous

Publications and source records attributed to T Quertermous.

76 records · Page 5Linked to original sources

PubMed1986

Cloning and sequence analysis of complementary DNA encoding an aberrantly rearranged human T-cell gamma chain.

Complementary DNA (cDNA) encoding a human T-cell gamma chain has been cloned and sequenced. At the junction of the variable and joining regions, there is an apparent deletion of two nucleotides in the human cDNA sequence relative to the murine gamma-chain cDNA sequence, resulting simultaneously in the generation of an in-frame stop codon and in a translational frameshift. For this reason, the sequence presented here encodes an aberrantly rearranged human T-cell gamma chain. There are several surprising differences between the deduced human and murine gamma-chain amino acid sequences. These include poor homology in the variable region, poor homology in a discrete segment of the constant region precisely bounded by the expected junctions of exon CII, and the presence in the human sequence of five potential sites for N-linked glycosylation.

Amino Acid Sequence↗

PubMed1986

T cell receptor gene rearrangements define a monoclonal T cell proliferation in patients with T cell lymphocytosis and cytopenia.

We have used probes from the T cell receptor beta and gamma chain loci to investigate the clonality of T lymphocytes in eight patients with T cell lymphocytosis and cytopenia (TCLC). This syndrome, which is strongly associated with rheumatoid arthritis, is characterized by peripheral blood and bone marrow lymphocytosis and neutropenia, red cell aplasia, or both. By means of T cell monoclonal antibodies and flow cytometry, T lymphocytes from patients with this syndrome have been shown to have characteristic immunologic features. Investigators have disagreed as to whether the syndrome represents a T cell malignancy or a more benign immunologic disorder. DNA from five of five patients with symptomatic "classic" T cell lymphocytosis with cytopenia demonstrated unique rearrangements of the T cell receptor beta chain locus, whereas neither of two patients with atypical features showed rearrangement. In addition, we found evidence for gamma chain rearrangement in those DNAs with clonal beta chain rearrangement. We thus postulate that the classic form of this syndrome is associated with a monoclonal proliferation of T cells. Its potential relationship to T cell chronic lymphocytic leukemia is discussed.

Aged↗

PubMed1983

Pacemaker failure resulting from radiation damage.

The authors present a case of radiation-induced pacemaker failure. After 2,000 rad (20 Gy) of photon irradiation for metastatic bronchogenic carcinoma, the pulse generator circuitry failed, producing a "runaway" rhythm. This suggests that present pacemaker circuitry may be more susceptible to irradiation than previously believed, and that even modest radiation doses can induce life-threatening arrhythmias.

Arrhythmias, Cardiac↗

PubMedDate not supplied

Human T-cell gamma genes contain N segments and have marked junctional variability.

The gamma-chain genes are encoded by immunoglobulin-like gene segments in germline DNA which rearrange during the somatic development of T cells to form an active gene. The protein produced by these genes has not been identified and the diversity of the proteins that the genes can express has not been determined. We expect that the diversity of expressed gamma-chains is produced by the same three mechanisms that produce diversity of other immunoglobulin-like genes: (1) germline variable (V) and joining (J) region repertoires; (2) somatic mutation; and (3) junctional diversity. To define the contribution of each of these mechanisms to the generation of gamma-chain diversity, several gamma-chain complementary clones and rearranged gamma-chain genes have been characterized. Most of these clones seem to encode a defective gamma-chain, the variable- and constant-region portions being joined such that they would not be translated in the same reading frame. Here we report that the germline J-region diversity of the human T-cell gamma-chain is very limited and that somatic mutation does not contribute to the diversity of the gamma-chains encoded by the cloned segments. However, the junctional diversity of these gamma-chain genes is extensive. We suggest that N sequences (template-independent sequences) have been inserted enzymatically into all of the gamma-chain genes characterized.

Base Sequence↗