International journal of cancer. Journal international du cancer
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Comparative Study
Common acquired naevi and the risk of malignant melanoma.
The relationship between common acquired naevi and malignant melanoma of the skin was assessed in a case-control study. IN 183 patients and 183 controls matched for sex, age and area of residence, there was a strong association between the presence of pigmented naevi on the arms and melanoma. ⋯ After adjusting for hair colour, propensity to sunburn and lifetime sun exposure, the final risk estimate was 30.1. Family history did not appear to be a determinant of disease independent of the above risk factors.
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The antimetastatic effects of heparin (40 units) and prostacyclin (PGI2, 100 microgram)1 were investigated in normal mice and in mice with depressed or activated natural killer (NK) cell activity. Both anticoagulants inhibited the formation of lung metastases after inoculation of the FI or F10 sublines of B16 melanoma. Inhibition of NK activity by treatment of mice with anti-asialo GM1 serum abrogated the antimetastatic effects of PGI2 or heparin. ⋯ Thus the antimetastatic effects of heparin and PGI2 are dependent on levels of NK activity in the host. Platelet aggregation and fibrin coating of the surface of tumor cells may be among the mechanisms by which hematogenously spread tumor cells are protected from destruction by NK cells. Anticoagulant drugs may exert antimetastatic effects by making tumor cells more vulnerable to the cytotoxic effects of NK cells, rather than by blocking adherence of tumor cells to vascular endothelium.
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After removal of SRBC rosette-forming T-cells from the peripheral blood, the residual, largely B-lymphocyte fraction of five infectious mononucleosis patients was found to contain 0.5-2% blast cells, positive for the EBV-determined nuclear antigen (EBNA). There was a rough parallelism between the presence of large lymphoblasts in the hematological smear, EBNS-positive large blasts in the B-cell fraction and the ability of the T-cell fraction to exert an EBV-specific lymphocytotoxicity on established cell lines in vitro. EBNA-positive B-cells and EBV-specific killer T-cells disappeared after the acute phase of the disease.