The discoid shape of blood platelets is supported by a circumferential bundle of microtubules. Removal of the microtubules by an antimitotic drug, vincristine, is associated with loss of lentiform appearance, formation of tubulin paracrystals, a depressed response to aggregating agents, and impaired secretory activity. Recent studies have suggested that the action of vincristine on platelet sec...

The microtubule-depolymerizing drug, vincristine, is effective in the treatment of acute lymphoblastic leukemia (ALL). Although vincristine resistance mechanisms have been extensively characterized in cell lines, their clinical relevance is poorly understood. The aim of the current study was to define clinically relevant mechanisms of vincristine resistance in a panel of childhood ALL xenograft...

Human lymphoid cells grown in long-term tissue culture have been used to study the cytotoxic effects of the combination of vincristine and prednisolone. The potentiating effects of this drug combination in vitro cannot be consistently shown if the drugs are addeded without attention to the growth rate of the cultured population. If the cultured cells have achieved maximum density and have remai...

Four children with vincristine toxicity unrelated to dose are described. Fever, haematological toxicity, and abdominal distension occurred 2-7 days after vincristine was given. Convulsions occurred 6-8 days after vincristine in all 4. Inappropriate secretion of antidiuretic hormone was thought to have occurred in 3 patients. 2 patients died during the acute toxicity phase. Necropsy findings did...

Chronic immune thrombocytopenia (ITP) is a condition associated with significant morbidity; however the management options for refractory ITP are often unsatisfactory despite various lines of treatment including splenectomy. The comparison of vincristine costs with other lines of treatment as intravenous immunoglobulin revealed many folds lower costs of vincristine. The aims of this study are: ...

We have determined the pharmacokinetics of liposomal vincristine, in a Lewis lung carcinoma solid tumor model in mice, with the aim of differentiating the contribution of liposomal and nonliposomal (released from liposomes) drug pools to the overall pharmacokinetic profile. Two types of liposomal formulations were used: one composed of 1,2 distearoyl-sn-glycero-3-phosphocholine/cholesterol (Cho...

We have previously shown that in the intact rat: (1) the inhibition of glucose-induced insulin release caused by vincristine occurred in the presence or absence of morphologic disruption of the beta-cell microtubules; and (2) vincristine, however, failed to inhibit arginine-induced insulin release, even in the presence of a marked disruption of the beta-cell microtubules. The present study furt...

Vincristine is metabolized to one primary metabolite, M1, by cDNA-expressed CYP3A4 and CYP3A5 and by CYP3A enzymes in human liver microsomes. For both systems, CYP3A5 is predicted to mediate approximately 80% of the CYP3A metabolism for individuals with high CYP3A5 expression (at least one CYP3A5(*)1 allele). In the current study, the role of CYP3A5 was quantified in the metabolism of vincristi...

BACKGROUND The aim of the present study was to assess the efficacy of vincristine-laden platelet transfusion for patients with refractory thrombocytopenia. PATIENTS AND METHODS Twenty evaluable patients who received vincristine-laden platelets for refractory thrombocytopenia were included in this retrospective study. Vincristine (1 mg) was added to the platelets and incubated for one hour pri...