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Biomedical subjects

K Toyama

Publications and source records attributed to K Toyama.

At least 541 records · Page 30Linked to original sources

Ionophoretic activities of phospholipids on human platelets.

The effects of phospholipids on calcium uptake by human platelets were investigated utilizing 45CaCl2. Among the phospholipids tested, cardiolipin and phosphatidic acid exerted a significant increase of calcium uptake by platelets. Calcium uptake was dependent upon cardiolipin concentration and incubation time. These phospholipids enhanced platelet aggregation induced by ADP (2 microM) or epinephrine (0.5 microgram/ml). Cardiolipin caused the significant release of serotonin from platelets in the absence of externally added calcium in the medium. These results may suggest that phospholipids activate platelets through their ionophoretic activities.

Biological Transport↗

Erythropoietin levels in the course of a patient with erythropoietin-producing renal cell carcinoma and transplantation of this tumor in nude mice.

Erythropoietin was measured by exhypoxic polycythemic mouse method in the course of a 64-yr-old male with renal cell carcinoma associated with erythrocytosis. Serum erythropoietin fluctuated with progression of the disease. Preoperative elevated erythropoietin (0.11 U/ml, p greater than 0.05) subsided after nephrectomy and again increased with developing lung metastasis (0.1 U/ml, p greater than 0.02). Erythropoietin was markedly increased in the tumorous extracts from primary renal cell carcinoma in the kidney (0.2 U/g, p greater than 0.01) and lung metastasis (0.8 U/g, p greater than 0.01). Renal cell carcinoma from the lung metastasis was transplanted into nude mice, resulting in erythrocytosis in some of these mic. In the erythrocytotic mice, erythropoietin was elevated to levels of 0.25--0.9 U/g (p greater than 0.01) in the tumorous extracts and increased (0.67 U/ml, p greater than 0.02) in the serum. These results indicate that this renal cell carcinoma is an erythropoietin-producing tumor, and this tumor has been successfully transplanted in nude mice for the first time.

Adenocarcinoma↗

Sarcomatous variant of malignant histiocytosis; a case report and review of the literature.

The case is that of a 21-year-old female with mediastinal and subcutaneous, tumors composed of sarcomatous growth of poorly differentiated histiocytes defined by enzyme histochemical staining, ultrastructural observation and detection of surface markers. At autopsy neoplastic cells in the solid tumor became less cohesive and pleomorphic with erythrophagia, while features in the lymph node draining from the tumor was compatible with the criteria of malignant histiocytosis. The place where such a sarcomatous variant of malignant histiocytosis should be placed within other histiocytic tumors is discussed and the literature reviewed.

Adult↗