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Biomedical subjects

M Carton

Publications and source records attributed to M Carton.

At least 37 records · Page 2Linked to original sources

Phase I/pharmacokinetic study of intraperitoneal teniposide (VM 26).

A phase I/pharmacokinetic study of the i.p. administration of teniposide (VM 26) was undertaken. Eighteen patients with various malignancies and refractory malignant ascites consented to enter this trial. The dose escalation was made according to the modified Fibonacci scheme. Twenty-four courses were evaluable for toxicity, response and pharmacokinetics. The maximum tolerated dose was reached at 450 mg/m2 and the limiting toxicity was myelosuppression, principally leukopenia. Abdominal pain occurred in one half of the courses but was not limiting. No partial remission, but two 'no change' were achieved for more than 2 months. A reduction or disappearance of ascites was seen in two patients. Pharmacokinetic studies, carried out in all courses, showed that the total exposure for peritoneal cavity averaged 10-fold greater than that of plasma. Based on the outcome of this phase I study, we could recommend phase II studies at a dose of 390 mg/m2 i.p. repeated every 4 weeks with a 4 h dwell-time.

Abdominal Neoplasms↗

Clinical and pharmacokinetic study of 96-h infusions of doxorubicin in advanced cancer patients.

A phase I and a pharmacokinetic study of 96-h infusions of doxorubicin were performed in order to evaluate the maximum tolerated dose with this schedule of administration. Seventeen patients suffering from a digestive carcinoma were included in the study and a total of 71 courses of treatment were performed. The starting dose was 15 mg/m2/day and was increased in 2.5 mg/m2/day increments. The main toxicities observed were neutropenia and mucositis, which became limiting from 22.5 mg/m2/day (90 mg/m2 over a 96-h period); this dose was therefore defined as the maximal tolerated dose. No objective response to treatment was observed. For further studies, the recommended dose should not exceed 20 mg/m2/day. A plasma plateau concentration of doxorubicin was reached within 24 h. Despite a constant infusion rate, the plasma concentration of doxorubicin showed transient variations in several patients. However, an average plasma concentration could be evaluated for 33 courses of treatment, and this was linearly related to the dose. Doxorubicinol was the only detected metabolite of doxorubicin and its plasma concentration progressively increased throughout infusion. A detailed pharmacokinetic study was performed in 13 courses of treatment. The mean plasma clearance of doxorubicin was 25.2 l/h/m2 and the mean terminal half-lives of doxorubicin and doxorubicinol were respectively 43.6 and 66.2 h. Urinary excretion of doxorubicin plus metabolite was regular from the 24th to the 96th hour of infusion; however, the proportion of doxorubicinol progressively increased in urine. The protracted half-life of this metabolite probably explains its accumulation during infusion.

Adult↗

Stage IE nonHodgkin's lymphoma of the testis: a need for a brief aggressive chemotherapy.

Primary nonHodgkin's lymphoma of the testis is a localized disease in 50 per cent of the cases. Clinical records and pathological material from 9 stage IE cancer patients treated at our institutions were reviewed. All but 1 patient had B cell type lymphomas of intermediate (6) or high (3) grade according to the Working Formulation. Mean survival was 49 months and actuarial survival was 74 per cent at 5 years. Chemotherapy differed with time and frequently was associated with subdiaphragmatic involved field and prophylactic contralateral testis radiotherapy. In view of the good prognosis of patients receiving doxorubicin-based chemotherapy and recent reports on low stage nonHodgkin's lymphoma we recommend an aggressive brief therapy for stage IE lymphoma of the testis after orchiectomy.

Actuarial Analysis↗

[Liposarcoma of the spermatic cord].

We review a new case of spermatic cord liposarcoma followed over a period of two years. After simple excision and 50 grays of radiotherapy had a local recurrence one year later; the patient a wide radical orchiectomy was then performed. A review of the literature illustrates the various clinicopathological data and their prognosis. The various treatments described are also analysed.

Aged↗

Pharmacokinetics of high-dose i.v. alizapride in prevention of cisplatin-induced emesis.

Alizapride is a new antidopaminergic-related benzamide with specific antiemetic properties. Pharmacokinetics at a high repetitive dose (16 mg/kg) shows a biexponential plasma decay with T1/2 alpha of 8.33 +/- 2.47 min and T1/2 beta 2.8 +/- 0.7 hr. Large Vdss and high total body clearance are apparent. We demonstrate an increase in drug exposure during the first 6 hr after CDDP infusion by shortening the interval between injections. We conclude that the rate of infusion of alizapride could be important in the efficacy of the drug.

Antiemetics↗

Cholesteryl ester transfer protein. Size of the functional unit determined by radiation inactivation.

Radiation inactivation was used to determine the functional Mr of cholesteryl ester transfer protein (CETP) in rabbit plasma from control and irradiated animals. This technique reveals the size of the functional unit required to carry out the transfer function. The functional Mr was calculated to be 70 000 +/- 3000 (mean +/- SD) for both control and irradiated rabbits. This result is in accordance with the Mr obtained by a completely different method, namely SDS-polyacrylamide gel electrophoresis of a partially purified (110-fold) rabbit CETP. The pI of this CETP was found by isoelectric focusing to be equal to 5.95. The results suggest that the functional unit of this enzyme is the monomer.

Animals↗

Triacylglycerol increase in plasma very low density lipoproteins in cyclophosphamide-treated rabbit: relationship with cholesteryl ester transfer activity.

We have studied the cholesteryl ester transfer between HDL and VLDL in cyclophosphamide-treated rabbits, in order to explain the abnormal cholesteryl ester partition between these two lipoprotein classes. The hypertriglyceridemia caused by treatment with the drug was associated with cholesteryl ester- and triacylglycerol-rich VLDL and with HDL poor in esterified cholesterol but relatively enriched in triacylglycerol. These two lipoprotein classes were characterized by their chemical composition and by gel filtration chromatography. VLDL particles were slightly larger in size, compared with controls. Different transfer combinations were envisaged between these abnormal lipoproteins and control ones. The transfer study involved the plasma fraction of d greater than 1.21 g/ml containing the cholesteryl ester transfer protein (CETP). It appeared that the chemical composition of lipoproteins was responsible for the level of cholesteryl ester transfer between lipoproteins. Actually, when the cholesteryl ester acceptor lipoproteins (VLDL) were enriched in triacylglycerol, the transfer was enhanced. Therefore, the effect of lipolysis on the transfer has also been explored. Lipoprotein lipase seemed to enhance the transfer of cholesteryl ester from HDL to VLDL when these lipoproteins were normal, but an important decline was obtained when triacylglycerol-rich VLDL were lipolyzed. This study defines the relationship between lipoprotein chemical composition and transfer activity of cholesteryl ester from HDL to VLDL.

Animals↗

Effects of an antimitotic agent (cyclophosphamide) on plasma lipoproteins.

A cyclophosphamide injection to male New Zealand white rabbits induced a pronounced hypertriglyceridemia and a hypercholesterolemia whose concentration was maximal at 16 hr. Different doses were studied. In this hyperlipemia significant changes in plasma lipoprotein fractions appeared: the very low density lipoproteins increased and the high density lipoproteins decreased. Lipid composition showed that HDL cholesterol was very low comparatively to a high VLDL cholesterol. The apoprotein composition of VLDL from treated rabbits was studied and compared to that of normal rabbits. After electrophoresis in urea/polyacrylamide gels, two new apoproteins which resembled those observed in irradiated rabbits appeared. The molecular weight of these proteins was about 10,000, and they focused into three bands with isoelectric points of 6.72, 6.42 and 6.10. Total lipoprotein lipase activity in treated rabbits decreased; it was very low with 32.5 mg/kg. This lipolytic activity remains to be studied after separation of hepatic triacylglycerol lipase and lipoprotein lipase activities by chromatography.

Animals↗

Irradiation-induced free cholesterol accumulation in very-low-density lipoproteins. Role of lipoprotein lipase deficiency.

Irradiation of rabbits induced an accumulation of free cholesterol in VLDL fraction. In the present study, an attempt was made to explain the abnormal free cholesterol enhancement. The study demonstrated that lecithin:cholesterol acyltransferase activity was normal in irradiated rabbits. In addition, electron microscopy examination of HDL revealed no changes after irradiation: spherical particles were present. On the other hand, ACAT activity was increased while neutral and acidic cholesteryl esterases were strongly decreased. Moreover, HMG-CoA reductase was 3-fold reduced after irradiation. These results show that neither cholesterol esterification nor cholesterol ester hydrolysis nor cholesterol biosynthesis are responsible for this increase of free cholesterol in VLDL. In contrast, we have shown that extra-hepatic lipoprotein lipase was deficient in irradiated rabbit plasma although synthesis in the adipocytes is normal. To investigate a hypothetical deficiency of VLDL catabolism, we performed experiments with injection of heparin and with labeled VLDL. These experiments show that, in irradiated rabbits, VLDL were not catabolized, since the radioactivity was recovered only in the VLDL fraction. This impaired VLDL removal was compatible with the deficiency of extra-hepatic lipoprotein lipase activity.

Adipose Tissue↗

Effects of threonine-poor apolipoproteins on post-heparin plasma hepatic triacylglycerol lipase and lipoprotein lipase.

Whole-irradiated rabbit pre-heparin plasma had an important inhibitory effect on hepatic triacylglycerol lipase and lipoprotein lipase activities, whereas control rabbit pre-heparin plasma slightly inhibited hepatic triacylglycerol lipase activity at a high concentration and enhanced lipoprotein lipase activity. As some apolipoproteins were known to modulate these two lipolytic enzymes, the inhibitory effects of irradiated rabbit plasma were investigated in apolipoproteins. Three apolipoproteins, with isoelectric points of about 6.58, 6.44 and 6.12, characterized by their low content in threonine (threonine-poor apolipoproteins) were produced in high concentrations in rabbit VLDL and HDL after irradiation. The effects of these apolipoproteins on control rabbit post-heparin plasma hepatic triacylglycerol lipase and extrahepatic lipoprotein lipase were studied. Threonine-poor apolipoproteins substantially inhibited the hepatic triacylglycerol lipase activity and enhanced the apolipoprotein C-II-stimulated activity of lipoprotein lipase. The amounts of these apolipoproteins in triacylglycerol-rich lipoprotein particles may determine the lipolytic activity of lipoprotein lipase and hepatic triacylglycerol lipase in triacylglycerol hydrolysis. The existence of another inhibitor of lipoprotein lipase remains to be determined.

Amino Acids↗