Effect of danazol on coagulation parameters and bleeding in hemophilia

Danazol was given orally at a dose of 600 mg/day to six hemophiliacs for eight to 14 weeks. All patients showed a significant decrease in activated partial thromboplastin time (APTT) beginning with the first measurement (two weeks) and persisting until use of the drug was discontinued. However, a corresponding increase in the deficient factor activity could not be consistently demonstrated. Despite the shortened APTT, bleeding episodes continued in the severe hemophiliacs and the patient with Christmas disease. In four patients, bleeding appeared to increase in severity or change in pattern, and in two cases the bleeding manifestations did not respond to usual factor infusions but responded to discontinuation of the drug therapy and further factor replacement. Euglobulin lysis times were measured in five patients (one hemophiliac and four with nonhemophilic conditions) who were receiving danazol. The lysis times were markedly shortened. Increased fibrinolytic activity may be responsible for the increased bleeding manifestations in danazol-treated hemophiliacs.

Phase I trial of esorubicin (4'deoxydoxorubicin)

A phase I study of 4'deoxydoxorubicin (esorubicin) was performed on an every-21-day bolus intravenous (IV) schedule in 36 patients with advanced cancer. Thirty-four patients were evaluable for toxicity analysis. Toxicity included mild nausea, occasional local skin reactions, and mild to moderate alopecia. Myelo-suppression was dose limiting. Clinically evident congestive heart failure was not observed. However, two patients developed premature ventricular contractions. Overall, esorubicin was better tolerated than doxorubicin at equally potent doses. Although response analysis was not the primary objective of this phase I study, minor responses were observed in melanoma, breast cancer, lymphoma, and gastric cancer. On the basis of this study, a starting dose of 30 mg/m2 IV every 21 days is recommended for good-risk patients with escalation to 32.5 mg/m2 depending on bone marrow tolerance. For patients with poor bone marrow reserve, a starting dose of 25 mg/m2 every 21 days is recommended. Phase II trials with esorubicin in this dosage schedule are clearly warranted in a wide variety of metastatic neoplasms including a substantial population of patients who have not received prior chemotherapy.

Treatment of advanced breast cancer with mitomycin C combined with vinblastine or vindesine

Mitomycin C together with either vindesine or vinblastine was given to 48 patients with previously treated advanced breast cancer. Thirteen (35%) of the 37 evaluable patients had a complete (one patient) or partial (12 patients) response. Overall median duration of response was 189 days (range, 90-700 days). Fifteen patients received mitomycin C and vindesine with six responses (40%) and a median response duration of 247 days (range, 162-700 days). Twenty-two patients received mitomycin C and vinblastine with seven responses (32%) and median response duration of 164 days (range, 90-330 days). Response duration for patients treated with mitomycin C plus vindesine was longer than that associated with mitomycin C plus vinblastine (p = 0.09). Significant toxicity included myelosuppression and neurologic symptoms, but was uncommon (less than 10% of patients). Therefore, the combination of mitomycin C and a vinca alkaloid appears to be useful in far-advanced refractory breast cancer.

Lack of inhibition by oxipurinol of 5-FU toxicity against human tumor cell lines

Allopurinol has been reported to decrease the gastrointestinal and bone marrow toxicity of 5-FU when administered in a high dose by continuous infusion. The effect of oxipurinol, the major metabolite of allopurinol, on 5-FU cytotoxicity against three human tumor cell lines was studied using a soft agar clonogenic assay. For both WiDR (colon) and T-47 (breast), 5-FU cytotoxicity was greater in the presence of oxipurinol than in its absence. Oxipurinol did not significantly affect 5-FU cytotoxicity against Hec-1A (endometrial). In none of the three lines was a protective effect of oxipurinol noted.

Interaction of lactoferrin, monocytes, and T lymphocyte subsets in the regulation of steady-state granulopoiesis in vitro

Colony-stimulating activities (CSA) are potent granulopoietic stimulators in vitro. Using clonogenic assay techniques, we analyzed the degree to which mononuclear phagocytes and T lymphocytes cooperate in the positive (production/release of CSA) and feedback (inhibition of CSA production/release) regulation of granulopoiesis. We measured the effect of lactoferrin (a putative feedback regulator of CSA production) on CSA provision in three separate assay systems wherein granulocyte colony growth of marrow cells from 22 normal volunteers was stimulated by (a) endogenous CSA-producing cells in the marrow cells suspension, (b) autologous peripheral blood leukocytes in feeder layers, and (c) medium conditioned by peripheral blood leukocytes. The CSA-producing cell populations in each assay were varied by using cell separation techniques and exposure of isolated T lymphocytes to methylprednisolone or to monoclonal antibodies to surface antigens and complement. We noted that net CSA production increased more than twofold when a small number of unstimulated T lymphocytes were added to monocyte cultures. Lactoferrin's inhibitory effect was also T lymphocyte dependent. The T lymphocytes that interact with monocytes and lactoferrin to inhibit CSA production are similar to those that augment CSA production because their activities are neither genetically restricted not glucocorticoid sensitive, and both populations express HLA-DR (Ia-like) and T3 antigens but not T4 or T8 antigens. These findings are consistent with results of our studies on the mechanism of lactoferrin's inhibitory effect with indicate that mononuclear phagocytes produce both CSA and soluble factors that stimulate T lymphocytes to produce CSA, and that lactoferrin does not suppress monocyte CSA production, but does completely suppress production or release by monocytes of those factors that stimulate T lymphocytes to produce CSA. We conclude that mononuclear phagocytes and a subset of T lymphocytes exhibit important complex interactions in the regulation of granulopoiesis.

Autoreduction of pure spinach cytochrome f: a light-dependent process inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea

A new procedure for the complete purification of spinach (Spinacea oleracea) cytochrome f, a tightly bound membrane protein, is described. The autoreduction of pure spinach cytochrome f has been confirmed using this new preparation. The process is now shown to be light-dependent and completely inhibited by the photosynthetic inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea. This inhibition is reversed by removing the inhibitor. The possible physiological implications of these observations are discussed.