The log/log relationship between the IC50 of cisplatin or carboplatin and the exposure time, determined by human tumor clonogenic assay (HTCA) and MTTAI (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay with additional incubation) using PC-14 cells, exhibited a straight line with a slope of -1, indicating that both drugs have AUC-dependent cytotoxicity (AUC, area under the c/t curve). The combined effect of cisplatin and carboplatin was estimated by the median-effect analysis using HTCA, and it was additive when the AUC ratio (AUC of free platinum from carboplatin/that from cisplatin) was low (3.2, 6.5 or 13.1 in each of PC-7, PC-9, PC-14, H-69, and K562). However, it was significantly worse at a higher AUC ratio (19.5 in PC-7, PC-9, and PC-14). The log/log relationship of each drug, determined by MTTAI using human bone marrow cells, showed that each drug exerts an AUC-dependent cytotoxicity on marrow granulocytes. When cisplatin and carboplatin were combined at an AUC ratio of 14, the therapeutic index was significantly better than that of carboplatin alone and less than that of cisplatin alone using K562, PC-9 and PC-14, indicating the usefulness of this combined therapy for tumor cells with high sensitivity to platinum compounds at this AUC ratio.
A 69 year old Japanese woman was hospitalized for emergency treatment of sudden onset of tetraplegia and somnolence. The patient had a long history of occipital pain without definite diagnosis. After admission, the patient progressively developed generalized palsy including respiratory paralysis, and died of bronchopneumonia. Autopsy revealed osteosarcoma of the cervical vertebrae with the features of Paget's disease involving the skull and the cervical vertebrae. Paget sarcoma is rare in Japan, where Paget's disease of the bone is an uncommon condition. A review of the world literature failed to reveal any reports describing Paget sarcoma of the cervical vertebrae. The present report indicates that the development of Paget sarcoma in the upper cervical vertebrae may cause life-threatening neurologic complications.
SummaryTo demonstrate whether the intravascular precipitation of fibrinogen is responsible for the toxicity of heparinoid, the relation between the toxicity of heparinoid in vivo and the precipitation of fibrinogen in vitro was investigated, using dextran sulfate of various molecular weights and various heparinoids.1. There are close relationships between the molecular weight of dextran sulfate, its toxicity, and the quantity of fibrinogen precipitated.2. The close relationship between the toxicity and the precipitation of fibrinogen found for dextran sulfate holds good for other heparinoids regardless of their molecular structures.3. Histological findings suggest strongly that the pathological changes produced with dextran sulfate are caused primarily by the intravascular precipitates with occlusion of the capillaries.From these facts, it is concluded that the precipitates of fibrinogen with heparinoid may be the cause or at least the major cause of the toxicity of heparinoid.4. The most suitable molecular weight of dextran sulfate for clinical use was found to be 5,300 ~ 6,700, from the maximum value of the product (LD50 · Anticoagulant activity). This product (LD50 · Anticoagulant activity) can be employed generally to assess the comparative merits of various heparinoids.5. Clinical use of the dextran sulfate prepared on this basis gave satisfactory results. No severe reaction was observed. However, two delayed reactions, alopecia and thrombocytopenia, were observed. These two reactions seem to come from the cause other than intravascular precipitation.
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