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Biomedical subjects

C M Steel

Publications and source records attributed to C M Steel.

At least 181 records · Page 10Linked to original sources
PubMed1975

In vitro immunological studies on East African cancer patients. II. Increased sensitivity of blood lymphocytes from untreated Burkitt lymphoma patients to inhibition of spontaneous rosette formation.

Frozen aliquots of peripheral blood mononuclear cells from patients with Burkitt's lymphoma (BL) at various stages of the disease have been compared with samples from East African children who were healthy or who suffered from non-malinant disorders. Using the sheep-cell rosette test (which is believed to identify T-lymphocytes), we found a significant reduction in the proportion of rosette-forming cells (RFC) in the samples from untreated BL patients. After reduction of remission the difference between BL patients and controls was abolished. Rosette formation was more readily inhibited by anti-lymphocyte globulin (ALG) in samples from untreated BL patients than in controls. On induction of remission the rosette inhibition curve shifted towards the control values. The findings are compatible with the presence, in untreated BL, of a circulating factor which impairs the capacity of T-lymphocytes to form rosettes with sheep erythrocytes. It remains to be established whether the functional capacity of T-cells to protect the host against tumour proliferation is also impaired.

Africa, Eastern↗
PubMed1975

In vitro immunological studies on east african cancer patients. III. Spontaneous rosette formation by cells from Burkitt lymphoma biopsies.

Spontaneous rosette formation was observed in eight out of nine Burkitt lymphoma biopsies. These were examined fresh and/or after culture in vitro for up to 48 h. The percentage of rosettes varied from 3.7% to 38%. There was a tendency for the percentage of rosettes to increase with time in tissue culture. It is suggested that the rosette-forming cells are T-lymphocytes infiltrating the tumour and functioning as a host defence mechanism against the proliferating tumour cells.

Africa, Eastern↗
PubMed1975

Glutaraldehyde and human T cell rosettes.

Blood mononuclear cells from ten healthy donors and cells from fifty cultured human lymphoblastoid lines were tested for the capacity to form rosettes with sheep erythrocytes. The effect of adding glutaralhehyde before scoring rosettes and the effect of substituting glutaraldehyde-fixed for fresh sheep cells were both examined. The results suggest that glutaraldehyde increases the apparent proportion of rosette-forming cells by altering the sheep erythrocytes in such a way that they will adhere to some B lymphocytes. Although a small number of cells carry both surface immunoglobulins and receptors for fresh sheep erythrocytes, the rosette test with fresh sheep cells identifies T lymphocytes more accurately in the absence of glutaraldehyde than in its presence.

Aldehydes↗
PubMed1975

Cytoplasmic receptor levels and glucocorticoid response in human lymphoblastoid cell lines.

The cytolethal response to treatment with prednisolone was investigated in vitro in eight human lymphoblastoid cell lines containing varying concentrations of specific cytoplasmic glucocorticoid receptors. A similar response was observed in seven of the lines irrespective of their concentration of cytoplasmic receptors and pharmacological doses of steroid, well above those required to saturate receptors in cell-free extracts, were required for a massive lethal response. One cell line derived from Burkitt's lymphoma was refractory to lethal effects even with pharmacological doses of steroid. A similar unresponsiveness to the cytolethal effect of prednisolone in vitro was observed in fresh lymphoblasts derived from patients with acute lymphoblastic leukaemia despite evidence of a satisfactory clinical response to therapy which included steroid. The resistance of human lymphoblastoid cells to treatment with glucocorticoids in vitro may result from a defect in activation subsequent to the binding of steroid to cytoplasmic receptors.

Burkitt Lymphoma↗
PubMed1975

Genetic studies on human lymphoblastoid cell lines: isozyme and cytogenetic heterogeneity in a cell line, with evidence for localization of the Pep A locus in man.

One hundred and thirty-three clones (60 mutagen treated, 73 controls) of the human male lymphoblastoid cell line F 137 have been examined for the electrophoretic pattern of more than 30 enzymes. In nine instances there was loss of activity of one allele of an X-linked or heterozygous autosomal locus. Seven of these involved the Pep A locus, and in every case the change was from the Pep A 2-1 phenotype to Pep A 2. Cytogenetic analysis of the parent line revealed a number of variants on the modal karyotype. On cloning, there appeared to be some selection for survival of non-modal cells. The proportions of the cytogenetically distinct populations within the bulk culture varied over a period of many months. There was a strong correlation in individual clones between loss of activity of the product of the Pep A1 allele and the presence in the cells of a 9/18 translocation. In addition there was one clone of phenotype Pep A 2 with a deletion of part of the long arm of chromosome 18. The data confirms the assignment of the Pep A structural locus to the distal half of the long arm of chromosome 18 and localizes it with some precision to the qter region. The Pep A 2 phenotype of the clones containing the 9/18 translocation could be the result of a small deletion eliminating the Pep A1 allele but not large enough to be detected cytogenetically. Alternatively inactivation of the Pep A1 allele may have occurred as a position effect resulting from the close association of heterochromatin from the centromere of 9 with the qter region of 18.

Cell Line↗
PubMed1975

A method for the storage and retrieval of laboratory data on human lymphoblastoid cell lines.

A computer-based system has been developed for the handling and retrieval of data on long-term human lymphoblastoid cell lines. It permits accurate recording of a wide range of genetic markers and other defined characteristics for the donor of each culture and for individual aliquots of any cell line. The data is recorded in relation to the in vitro age of each aliquot studied and the programme is designed to permit both the sequential examination of a single cell line and the comparison of lines of different origins. It is hoped that, by the application of this type of system, the confusion which has arisen in relation to other long-term cell lines (and which threatens to develop in relation to human lymphoblastoid cell lines) may be avoided and that the exchange of information between laboratories may be facilitated.

Cell Line↗
PubMed1975

Burkitt's lymphoma and HL-A antigens.

Studies were carried out on the distribution of HL-A antigens in 33 patients with Burkitt's lymphoma from several tribal groups in Kenya. The frequency of distribution of the HL-A antigens was not significantly different in these patients from that in a selected control population. Difficulty was experienced in the precise identification of some HL-A antigens in Africans using a Caucasoid serum panel, in particular those associated with HL-A7 and to a lesser extent, the "W19" complex.

Adolescent↗