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Biomedical subjects

T A Reichert

Publications and source records attributed to T A Reichert.

9 recordsLinked to original sources

Fc-receptor for mouse IgG1 (Fc gamma RII) and antibody-mediated cell clearance in patients treated with Leu2a antibody.

A pilot study was performed to explore the clinical potential of Leu2a antibody in reversing acute renal allograft rejection. Anti-Leu2a, a murine IgG1 monoclonal antibody (mIgG1 mAb), is specific for the CD8 molecule that is expressed in high density on class I reactive T cells. Of the 6 recipients treated with anti-Leu2a, two responded with a complete reversal of rejection with long-term allograft function maintained for over a year. In two other recipients, acute rejection was initially reversed, but later rejection episodes resulted in allograft failure at 2-3 months posttreatment. Rejection in the two other recipients showed no response to Leu2a mAb treatment. Specific depletion of peripheral blood CD8+ cells occurred in four of the six recipients. Even in this small series, it was evident that cell clearance was neither necessary nor sufficient for reversal of rejection. However, a complete correspondence between cell clearance and the ability of the recipients' mononuclear cells to undergo mitogenic response to the mIgG1 anti-CD3 (Leu4) mAb in vitro was noted. Binding of IgG1 mAb to the Fc-receptor (Fc gamma RII/CD32) expressed on blood monocytes is known to be essential for the T cell mitogenic response to soluble mIgG1 CD3 mAb in vitro. Our data suggest that binding to Fc gamma RII may be an essential step in the process of mIgG1 Leu2a mAb-mediated cell clearance in vivo.

Animals

The phenotypic diversity of peripheral T-cell lymphomas: the Southeastern Cancer Study Group experience.

Four member institutions of the Southeastern Cancer Study Group (SECSG) investigated 27 cases of malignant lymphoma proved to be of T-cell origin by a frozen section immunoperoxidase technique. The specimens were sent to one central laboratory in Michel's transport medium, where phenotyping studies were performed with a large number of monoclonal antibodies. The phenotypes encountered differed as a group from that reported for lymphoblastic lymphoma, but there was significant diversity within the peripheral T-cell lymphomas. Most tumors were of a mature helper/inducer phenotype (Leu-3+, Leu-2-), but nine of the 27 lymphomas expressed Leu-3 and Leu-2 in other combinations. Half of the lymphomas expressed abnormal T-cell phenotypes in that one or more pan-T-cell markers usually present in nonneoplastic T-cell proliferations were absent. Antibody 3A1 was the pan-T marker that was most frequently lacking in the peripheral T-cell lymphomas. The tumors were also studied for their expression of three markers associated with T-cell activation--HLA-DR, transferrin receptor, and interleukin 2 receptor. The majority of the lymphomas expressed one or more activation markers. However, these three markers appear to be expressed independently. In general, there was no simple correlation between the phenotype of the tumor and the histologic appearance, although neoplasms of morphologically higher grades were somewhat more likely to express T-cell activation markers.

Adult

Spatial summation effects on two-component grating thresholds.

Some experimental studies of subthreshold summation between sinusoidal grating components have been interpreted as showing very narrow channel bandwidths in human visions. This paper discusses an alternative interpretation of these experiments based on consideration of probability-summation effects among spatially distributed detectors. We conclude that frequency-selective channels must still be hypothesized in order to fit the data, but the channel bandwidth may be much wider than earlier interpretations suggest.

Humans

Molecular evolution as a process of message refinement.

Amino acid sequences are often said to code for proteins. Taking that statement literally, we propose a methodology in which protein sequences appear as messages and as such are amenable to the techniques of signal analysis. Not only does this view of amino acid sequences as messages appear to be tenable, but the clarity of expression of these sequences seems to increase, i.e., the noisiness decreases, consonant with notions of ascendancy in the hierarchy of morphological taxonomy.

Amino Acid Sequence