Relationship between graft cytochrome P-450 3A content and early morbidity after liver transplantation.

Cytochrome P-450 3A metabolizes CsA into several metabolites with very limited pharmacological activity and toxicity. In 40 liver donors, the relative concentrations of P-450 3A was assessed by immunoblot analysis using a specific monoclonal antibody exhibited a 10-fold variation (mean = 92 +/- 50 arbitrary units [AU]/mg) in levels. Problems consequent upon CsA usage (nephrotoxicity, neurotoxicity, and hypertension) occurred in 8 of 34 transplant recipients in the immediate postoperative period, and in these 8 patients the problems were always associated with low graft P-4503A levels (mean = 52 +/- 19 A.U./mg, P = 0.0003, cf. patients with no toxicity). Four of these patients had CsA levels that were also high, but 4 had CsA levels in the therapeutic range. Episodes of early graft rejection were related to higher P-450 3A levels (mean = 110 +/- 24 A.U./mg). Cytochrome P-450 3A levels were also found to be inversely related to CsA whole blood levels (assessed with a specific antibody 12 hr after the intravenous infusion of CsA at 1 mg/kg in the recipients (P < 0.02). Cytochrome P-450 3A can provide information that should allow individualized immunosuppression with CsA maintaining therapeutic levels but avoiding toxicity in susceptible individuals.

Oxalato-platinum or 1-OHP, a third-generation platinum complex: an experimental and clinical appraisal and preliminary comparison with cis-platinum and carboplatinum.

A new platinum complex, oxalatoplatin or l-OHP, which, at the same metal dose in experimental tests is as efficient as cisplatin, and is more so at a lower metal dose than carboplatin; which is as efficient in human tumors of the testis and ovary as these other analogs, and more so in melanoma and breast cancer; which is not nephrotoxic, cardiotoxic or mutagenic, and hardly hematotoxic and neurotoxic, is described and compared with the above-mentioned platinum complexes. Combined with 5Fu, it induces a high number of remissions in colorectal cancer, and has brought about cures in inoperable gastric cancers. Combined with carboplatin, it has resulted in a high proportion of cures in L1210-carrying mice, which no other two-by-two combination of these complexes has achieved.

Changes in erythromycin pharmacokinetics induced by renal failure.

As erythromycin ototoxicity appears to be favored by renal insufficiency, its pharmacokinetics were assessed in chronic uremic patients treated by maintenance hemodialysis in comparison with normal subjects. Two groups of 8 patients each were studied, the first one on an interdialytic day, the second immediately after the end of an hemodialysis session. All subjects ingested a single dose of 1 gram of erythromycin ethylsuccinate. Times of peak serum concentration and biological half-lifes were similar in patients and in controls. Maximum serum concentrations and areas under the serum concentration time-curve were higher in patients than in controls whereas apparent oral clearances were lower in the former. The differences between the two groups of patients were not significant. These pharmacokinetic changes are suggestive of an enhanced bioavailability of erythromycin in chronic renal failure which might predispose uremics to the ototoxicity of the drug.

Clinical pharmacokinetics of cicletanine hydrochloride.

Results of the different pharmacokinetic studies performed with cicletanine, the first derivative of a new class of antihypertensive drugs, the furopyridines, are reviewed in this article. Pharmacokinetic studies with healthy subjects have shown that this drug is rapidly absorbed (time to Cmax about 0.65 h). It is strongly bound to plasma proteins (90%), with a volume of distribution of 37 l. The elimination half-life is between 6 to 8 h and elimination itself is mixed: renal and hepatic. The parameters are unchanged in young hypertensives. Pharmacokinetic studies in hepatic failure have shown that the mean retention time is about 6 h; the pharmacokinetic parameters are only slightly modified except in the case of cirrhosis with ascites and extra hepatic obstruction. The modification of pharmacokinetics in patients with renal failure is related to the severity of the condition. Small changes appear with moderate failure whereas important variations occur in severe renal failure.

Study of human neurovegetative and hematologic effects of environmental low-frequency (50-Hz) electromagnetic fields produced by transformers.

A survey of neurovegetative and hematologic disorders was conducted in a population (n = 13) exposed occupationally to environmental electromagnetic fields; the population was matched with 13 control subjects. The exposed subjects worked at least 8 h/d for 1-5 y in premises located above transformers and high-tension cables, and the subjects were submitted to low-frequency electromagnetic fields (i.e., 50 Hz) of 0.2 microT-6.6 microT. The subjects were matched with respect to socioeconomic category, sex, and age with a control population of subjects that worked in premises outside of the immediate vicinity of transformers or high-tension cables. The exposed population had a significant increase in degree of certain neurovegetative disorders (i.e., physical fatigue, psychical asthenia, lipothymia, decreased libido, melancholy, depressive tendency, and irritability). In addition, the population experienced a significant fall in total lymphocytes and CD4, CD3, and CD2 lymphocytes, as well as a rise in NK cells. Leukopenia and neutropenia were also observed in two persons permanently exposed to doses of 1.2-6.6 microT. The disorders disappeared when exposure stopped, and they reappeared on reexposure.

[Pharmacokinetic study of pyrazinamide and pyrazinoic acid in subjects with normal renal function and patients with renal failure]. / Etude pharmacocinétique du pyrazinamide et de l'acide pyrazinoïque chez le sujet à fonction rénale normale et l'insuffisant rénal.

The main pharmacokinetic parameters of pyrazinamide and pyrazinoïc acid (its major metabolite) were determined after oral administration of 1,500 mg/d in 10 patients with normal renal function and of 1,000 mg/d in 10 patients with impaired renal function (renal insufficiency). This study shows that, with these dosage regimens, almost all the pharmacokinetic parameters are identical for pyrazinamide and pyrazinoic acid in patients with normal renal function and patients with impaired renal function. Comparison of results between patients allows us to propose a dosage regimen of 1,000 mg/d as maintenance in patients with renal insufficiency.

[Comparison of tacrine hepatotoxicity in patients with Alzheimer disease or AIDS]. / Comparaison de l'hépatoxicité de la tacrine chez des patients atteints de la maladie d'Alzheimer ou du SIDA.

Previously used in Alzheimer disease Tacrine (THA): tetrahydroaminoacridine has shown a rise of hepatic transaminase enzyme activity (TEA) in 18% of patients for Summers and 19% for Ames. Although studies using THA from USA or Canada have noticed a rise of TEA in 30% of the patients, after a treatment course with French THA we also have noted a rise of TEA in 12% of the Alzheimer patients. However, these secondary effects yielded to the end of treatment. These studies have been done with THA from different origins and different associations. Summers, the Canadian group and the French one have used THA in association with lecithin, when american group study has been made with no additional product. Therefore we have initiated a trial with oral THA in AIDS patients. 52 patients with HIV infection (26 in the IVC1 group and 26 in IVC2 group) have been treated with the same THA as the one used for Alzheimer french group. The common dosage was 150 to 200 mg (3 to 4 of 50 mg dosing capsules per day). The THA has been synthetized such as having an over 99% pureness product. After a period of 260 months/patient no elevation of TEA has been noted in any patients of our group. These results observed in HIV advanced patients with this THA are discordant with the one observed in Alzheimer's study. The dosage used in AIDS is twice higher than the one used for Alzheimer which gives us credit to the lack of hepatic toxicity in HIV advanced patient after 7 months of treatment.

[Proposal of a new procedure for the exploration of hepatocellular function. The trimethoxybenzene test (TMB)]. / Proposition d'un nouveau procédé d'exploration de la fonction hépatocellulaire. Le "test au triméthoxybenzène" (TMB)

The authors propose a new method of exploration of liver cell function based on the study of demethylation of a rapidly assimilated atoxic compound, trimethoxybenzene (TMB) in dimethoxy-hydroxybenzene (DMHB). Whereas in normal subjects, the urinary excretion of the metabolites was rapid and marked, 180 mg within 3 hours after taking a 400 mg dose, in patients with liver cell failure, the excretion of DMHB was considerably reduced, 80 to 95% in cirrhosis.