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Biomedical subjects

C Potvin

Publications and source records attributed to C Potvin.

25 records · Page 2Linked to original sources
PubMed1975

Thymus-dependent lymphocyte levels in bronchogenic carcinoma: correlations with histology, clinical stage, and clinical course after surgical treatment.

The in vitro spontaneous lymphocyte rosette (T cell) assay was used to determine cellular immunologic competence in 112 patients with bronchogenic carcinoma. Among preoperative patients with localized tumors. T cell levels were significantly lower than in 237 normal controls. With advanced stages of disease, T cell levels declined progressively among patients with squamous cell carcinoma, oat cell carcinoma, and undifferentiated carcinoma, but not among patients with adenocarcinoma. Squamous carcinoma patients considered cured had persisting low T cell levels, but cured adenocarcinoma patients had normal levels. Serial determinations that showed a fall in T cell levels preceded the development of clinically evident metastases by an average of 2.5 months. Postoperative patients with rising T cell levels have remained clinically free of disease. The data indicate that T cell levels correlate with extent of tumor and clinical course of patients with bronchogenic carcinoma. The assay may, therefore, provide a rational basis for the selection of patients who are at high risk for the development of recurrence after surgical resection and who may benefit from the early institution of adjunctive therapy.

Adenocarcinoma↗
PubMed1975

Identification of complement-receptor lymphocytes (B cells) in lymph nodes and tumor infiltrates.

To monitor the distribution of lymphocyte sub-populations infiltrating tumors, a simplified modification of standard techniques was developed to identify the complement-receptor B lymphocytes in frozen tissue sections. This technique is based on binding of antibody-coated bovine erythrocytes by B lymphocytes in the presence of sub-hemolytic concentrations of mouse complement. B lymphocytes can be identified in frozen tissue sections by adherent sensitized bovine erythrocytes. The specificity of the technique for B lymphocytes was established by 1) absence of spontaneous rosette formation with bovine erythrocytes by human T lymphocytes, 2) specific binding of bovine erythrocyte-antibody-complement complexes to B cell regions of normal lymph nodes and spleen and 3) binding of erythrocyte-antibody-complement to a high proportion of chronic lymphocytic leukemia (a B cell leukemia) lymphocytes. Five transitional carcinomas studied had regions of mononuclear infiltration that were virtually devoid of complement-receptor lymphocytes. The results suggest that lymphocytes infiltrating bladder carcinomas may be predominantly T lymphocytes.

Animals↗
PubMed1975

The immunobiology of skin cancer.

The immunobiology of skin cancer was studied with thymus-dependent lymphocyte (T cell) levels (an in vitro measure of cellular immunity), with lymphocytic infiltration (LI) of the tumor (an in vivo measure of host-tumor relationship), and with HL-A typing (a genetic measure of histocompatibility). The T cell levels in preoperative patients with squamous (SCC) and basal (BCC) cell carcinoma were significantly lower than in the non-cancer control population (normals). The T cell levels were significantly lower in patients with large tumors than in those with small tumors. The T cell levels remained significantly low in patients cured of large tumors, but were normal in those cured of small tumors. Patients with Bowen's disease not only had T cell levels significantly lower than normal (as a group), but there was also a significant increase in the number of patients who had T cell levels less than two standard deviations below the normal mean. This may signify that they have a greater risk of developing a second kind of malignancy elsewhere. There was a direct correlation between the degree of lymphocytic infiltration (LI) of the tumor, the tumor size, and the T cell level. Small, well-localized tumors had a marked LI and high T cell levels--while the large, deeply invasive tumors had a minimal, or absent, LI and low T cell levels. The presence of HL-A antigens 1 and 8 correlated both with a tendency toward large tumors and with low T cell levels. This may represent the association of a human immune response gene with the human histocompatibility locus. Possibilities for the application of these findings in the clinical management of skin cancer are discussed.

Adult↗
PubMed1975

Correlations among cutaneous reactivity to DNCB, PHA-induced lymphocyte blastogenesis and peripheral blood E rosettes.

Comparisons of the results obtained in a study of fifty-two patients with genitourinary malignancies using three assays to monitor the thymus-dependent immune system (delayed cutaneous hypersensitivity to DNCB, PHA-induced lymphocyte blastogenesis, and peripheral blood E rosette-forming lymphocyte counts) yielded statistically significant positive correlations between the DNCB and PHA assays in twenty-one of twenty-eight instances, the DNCB and E rosette assays in thirteen of sixteen instances, the PHA and E rosette assays in twenty-eight of thirty-six instances, and among the DNCB, PHA and E rosette assays in ten of fourteen instances. The results suggest that both PHA-stimulated lymphocyte blastogenesis and peripheral blood E rosette-forming lymphocyte levels provide meaningful in vitro correlates of cell-mediated immunity.

Aged↗
PubMed1975

In vitro lymphocyte reactivity and T-cell levels in chronic cigarette smokers.

Peripheral blood total leucocyte, lymphocyte and thymus-dependent lymphocyte (T cell) levels and in vitro lymphocyte reactivity (LR) to phytohaemagglutinin (PHA) were determined in 153 chronic cigarette smokers and 115 non-smokers ranging in age from 20 to 78 years. Total leucocyte, lymphocyte and T-cell levels were significantly elevated in smokers. There was no correlation with age. LR to PHA was significantly higher in smokers less than 40 years of age or in those with a 20 pack-year or less history of cigarette consumption. Older smokers or those with a history of heavier cigarette consumption did not differ from normals. The results contrast with previous demonstrations of suppression of immune reactivity after exposure to tobacco products. The possible effects of the apparent stimulation of the lymphoid system by chromic cigarette consumption is considered.

Adult↗