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Biomedical subjects

I G Barr

Publications and source records attributed to I G Barr.

26 records · Page 2Linked to original sources
PubMed1986

Lymphoma immunotyping by paraffin immunoperoxidase and cell suspension methods--a comparative study.

Immunoperoxidase staining incorporating an enzyme digestion step was performed on paraffin sections of 84 biopsy cases of lymphoproliferative disorders. Monoclonality was demonstrated in 100% of plasmacytomas and related tumours, and in 66% of non-Hodgkin's lymphomas. In 83% of lymphomas the immunoglobulin class was IgM and the light chain distribution was kappa 64% and lambda 36%. Polyclonality was found in 89% of cases of reactive lymphoid hyperplasia and within Reed-Sternberg cells in 55% of cases of Hodgkin's disease. Similar results were obtained by dispersed cell studies in 56 overlapping cases. The concordance rate between the two methods in 40 cases of non-Hodgkin's lymphoma was 67.5%. Reasons for the inconsistencies are discussed. Immunoperoxidase staining of enzyme digested paraffin sections is useful in the diagnosis of B cell lymphoproliferative disorders with a particular role in centres where cell suspension studies are not available or when there is no access to fresh tissue.

Cytological Techniques↗
PubMed1984

PHM 14: a novel monoclonal antibody that reacts with both normal and neoplastic human B cells but not B-CLL.

The reactivity of PHM 14, a monoclonal antibody to B cells produced in our laboratory was compared with Leu 10, a commercially produced antibody. Flow microfluorometric analysis showed that both PHM 14 and Leu 10 reacted with normal B cells, a variety of B cell lines and with B cell leukaemias and lymphomas, except in the case of B-CLL where PHM 14 reacted with a minority of cases, whereas Leu 10 reacted with a majority. PHM 14 and Leu 10 did not react with normal monocytes, granulocytes, T cells, T cell lines or with T cell leukaemias or lymphomas. Specificity of PHM 14 for B cells was further supported by the demonstration that PHM 14-positive blood cells, sorted from PHM 14-negative blood cells, reacted with polyclonal anti-immunoglobulins and with a panel of B cell markers but did not react with markers for T cells, monocytes, granulocytes or NK cells. Our results suggest that both PHM 14 and Leu 10 should be useful diagnostic reagents in the investigation of B cell-derived leukaemias and lymphomas.

Antibodies, Monoclonal↗
PubMed1984

Thymic sensitivity to sex hormones develops post-natally; an in vivo and an in vitro study.

In vitro thymic organ cultures were used to examine the effects of the sex hormones estradiol and dihydrotestosterone on thymocytes. In contrast with the marked loss of cortical thymocytes seen in vivo with these hormones, no effect was apparent in vitro even at concentrations up to 10(-6) M. The glucocorticoid dexamethasone caused severe depletion in vivo and in vitro. Thymic androgen and estrogen receptors were determined; in the newborn animals up to 2 wk of age, receptor levels were barely detectable. The possibility of indirect modulation of thymic function by steroids in vivo was investigated by culturing thymic lobes in media containing serum from animals treated with these hormones. Only sera from dexamethasone-injected animals caused changes in cell size, number, viability, or phenotype in the culture system. The mechanism for the previously reported effects of sex steroids on the neonatal thymus therefore remains to be elucidated.

Aging↗
PubMed1983

Routine flow cytometric diagnosis of lymphoproliferative disorders.

The results of the analysis of suspected lymphoproliferative disorders using flow cytometry (FACS II) over the past 12 months have been evaluated and assessed with respect to "conventional" microscopical examination. The major advantages in using these methods is the speed, the number of parameters which are capable of measurement, the sensitivity, and the ability to quantitate large numbers of cells for a particular criterion. These qualities have proved extremely helpful in the diagnosis of chronic lymphocytic leukemia, acute lymphoblastic leukemia, lymphoma, and other abnormalities. The combination of flow cytometry and a panel of monoclonal antisera (many of which are available commercially) allows the investigator a system of fine resolution which can confidently identify or characterize an abnormal clone or population of cells. With the increase in advanced flow cytometers, it is suggested that time should be allocated for the routine analysis of possible lymphomas and leukemias to allow quick and accurate evaluations of the disease status.

Antibodies, Monoclonal↗
PubMed1983

Dexamethasone induces different cellular protein synthetic responses in PNA+ and PNA- mouse thymocyte subpopulations.

Thymocytes from adrenalectomized BALB/c male mice were separated by peanut agglutination (PNA) into cortical, corticosensitive, PNA+ cells and larger, medullary, corticoresistant, PNA- cells; the extent of cross-contamination of PNA+ and PNA- cells, and vice versa, was checked by flow microfluorometry. Glucocorticoid receptor profiles were established with 3H-dexamethasone as probe; no differences in receptor affinity or cellular concentration, or in cytoplasmic and nuclear compartmentalization were seen between PNA+ and PNA- cells. On two-dimensional gel electrophoresis, PNA+ and PNA- thymocytes from oil-injected (control) adrenalectomized mice showed patterns of incorporation of 35S-methionine into protein that differed in at least 12 spots, as revealed by autoradiography. PNA+ and PNA- cells from mice treated with submaximal (6 micrograms/day) or near-maximal thymolytic doses of dexamethasone (20 micrograms/day) were also examined by two-dimensional gel electrophoresis. Both PNA+ and PNA- cells showed substantial, overlapping dexamethasone-induced changes in protein synthetic profiles.

Animals↗
PubMed1982

Dihydrotestosterone and estradiol deplete corticosensitive thymocytes lacking in receptors for these hormones.

The sex steroids dihydrotestosterone (DHT) and estradiol (E2), were found to deplete the same cortical population of thymocytes as the glucocorticoid dexamethasone (DM) in intact and in adrenalectomized, castrated mice. Although receptors for DM were demonstrated in this cortical population, none were found for E2 or DHT. We suggest that the sex steroids bind to other thymic elements, possibly thymic reticular epithelial cells, which may in turn act secondarily on cortical thymocytes, or their precursors within the thymus.

Animals↗