Kinetic assessment of persistent halogenated xenobiotics in cell culture models: comparison of mono- and poly-halogenated compounds.

We evaluated the suitability of single and multiple cell type cultures as model systems to characterise cellular kinetics of highly lipophilic compounds with potential ecotoxicological impact. Confluent mono-layers of human skin fibroblasts, rat astrocytoma C6 cells, non-differentiated and differentiated mouse 3T3 cells were kept in culture medium supplemented with 10% foetal calf serum. For competitive uptake experiments up to four different cell types, grown on glass sectors, were exposed for 3h to (14)C-labelled model compounds, dissolved either in organic solvents or incorporated into unilamellar lecithin liposomes.

The elaboration of the 'Stockholm convention' on persistent organic pollutants (POPs): a negotiation process fraught with obstacles and opportunities.

The conclusion in December 2000 of the negotiations for the 'Stockholm Convention' can clearly be labeled as a success. The Convention text was negotiated in merely five sessions of the Intergovernmental Negotiating Committee (INC) and accomplished after its fifth session despite the fact that numerous controversial issues, such as the inclusion of new substances under the ambit of the Convention, the acknowledgement of the precautionary principle or--clearly most controversial--the financing mechanisms, remained to be resolved. This paper attempts to provide a somewhat impressionistic account of the negotiations leading to the conclusion of the 'Stockholm Convention' as experienced by the members of the Swiss delegation participating in the negotiations of the INC.

Determination of polychlorinated dibenzo-p-dioxins and dibenzo-furans in solid residues from wood combustion by HRGC/HRMS.

PCDD/PCDF were determined in solid samples from wood combustion. The samples included grate ashes, bottom ashes, furnace ashes as well as fly and cyclone ashes. The solid waste samples were classified into bottom and fly ash from native wood and bottom and fly ash from waste wood.

Clearance of atrazine in soil describing xenobiotic behavior.

The primary aim of this study was to evaluate the "clearance concept" as a tool for describing the behavior of xenobiotic movement into and through soils. As an example, degradation of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) with the formation of metabolites 2-chloro-6-isopropylamino-s-triazine (desethylatrazine) and 2-chloro-4-ethylamino-s-triazine (desisopropylatrazine) was investigated. Atrazine was sprayed post-emergently in doses of 0.

Organic micropollutants in Swiss sewage sludge.

Sludges from sixteen municipal and eleven industrial Swiss sewage treatment plants were analysed for adsorbable organic compounds (AOX), chlorinated pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons. Except for the AOX values, which were significantly higher (p < 0.05) in industrial sludges, there was no significant difference between industrial and municipal sludges.

Excessive motor impairment two hours after triazolam in the elderly.

The pharmacokinetics of triazolam 0.25 mg p.o.

Increased urinary excretion of bile alcohol glucuronides in patients with primary biliary cirrhosis.

The bile alcohol glucuronides in urine of 12 patients with primary biliary cirrhosis (PBC), 10 patients with chronic active hepatitis (CAH), and 6 healthy volunteers were analyzed by capillary gas-liquid chromatography-mass spectrometry. In all subjects studied, the major urinary bile alcohol was found to be 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24,25-pentol (C26 pentol). In PBC patients, the excretion of C26 pentol (main isomer) was significantly increased above values observed in healthy volunteers (mean +/- SD = 5.

Preserved cytosolic and synthetic liver function in jaundice of severe extrahepatic infection.

We investigated prospectively 9 adult patients with the syndrome of jaundice complicating severe extrahepatic infection both clinically and by quantitative liver function tests. Five patients having severe extrahepatic infection without jaundice were used for comparison. Intraperitoneal infection was found to be a major risk factor for development of jaundice.

A bile alcohol sulfate as a major component in the bile of the small skate (Raja erinacea).

The nature of bile alcohols and bile acids in gall-bladder and hepatic bile from perfused livers of the small skate (Raja erinacea) has been investigated. The main bile alcohol sulfate was isolated by thin-layer chromatography and analyzed by fast atom bombardment mass spectrometry and 13C NMR. Following solvolysis and purification on Lipidex-DEAP, the bile alcohol profile was measured by capillary gas-liquid chromatography-electron impact mass spectrometry.

Altered bile acid profiles in duodenal bile and urine in diabetic subjects.

The bile acid composition in duodenal bile was analysed in 22 diet-treated and 11 insulin-treated middle-aged patients with diabetes mellitus and in 20 normoglycaemic controls. In 10 subjects with diabetes mellitus the bile acid profile in urine was also investigated. In the non-insulin-dependent diabetic patients the percentage of cholic acid was reduced and that of deoxycholic acid increased.

Acetylation of acetylhydrazine, the toxic metabolite of isoniazid, in humans. Inhibition by concomitant administration of isoniazid.

The effect of isoniazid and its metabolites on the disposition of acetylhydrazine, a toxic metabolite formed from isoniazid, was studied in humans. Acetylhydrazine was administered i.v.

Cholesterol synthesis in the perfused liver of pregnant hamsters.

Pregnancy is a risk factor for the development of cholesterol gallstones. In pregnant women, biliary cholesterol saturation and secretion are increased. To investigate whether this was due to increased cholesterol synthesis, we studied hepatic cholesterol synthesis in Syrian Golden hamsters.

Bioavailability determination of lidocaine by capillary gas chromatography ammonia chemical ionization mass spectrometry.

A method was developed to measure bioavailability of lidocaine by simultaneous peroral and intravenous dosing. Lidocaine hydrochloride corresponding to 125 mg base was given perorally. Simultaneously, 30 mg of deuterated lidocaine-d3 were injected intravenously.

Mechanism of the excessive sedative response of cirrhotics to benzodiazepines: model experiments with triazolam.

Mechanisms responsible for disproportional sedation resulting from triazolam administration to patients with cirrhosis were investigated. Ordinary sedative doses (0.25 mg) were given p.

Increased urinary excretion of toxic hydrazino metabolites of isoniazid by slow acetylators. Effect of a slow-release preparation of isoniazid.

To test the hypothesis that slow acetylators, who may have a greater risk of developing isoniazid hepatitis than rapid acetylators, are exposed to more acetylhydrazine and hydrazine, two toxic metabolites of isoniazid, the urinary excretion of hydrazino metabolites of isoniazid was measured following the ingestion of 300 mg isoniazid. Slow acetylators (n = 7) excreted significantly more isoniazid (32.4 vs 9.

Bile acids and bile alcohols in two patients with Zellweger (cerebro-hepato-renal) syndrome.

The Zellweger cerebro-hepato-renal syndrome (CHRS) is a rare hereditary disease in which there is a generalized deficiency of peroxisomal function. Liver peroxisomes are important for the conversion of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid into cholic acid, and, consequently, 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid and metabolites of this bile acid precursor accumulate in serum and bile of patients with CHRS. Little is known about the urinary excretion of bile acids in this disease.

Defective bile acid transport in an animal model of defective debrisoquine hydroxylation.

Bile acid transport in female DA (dark Aguti) rats, a model for debrisoquine hydroxylation deficiency in man, was investigated. Compared to hydroxylation competent male DA and Sprague-Dawley rats of either sex, the female DA rat had a significantly lower taurocholate maximal secretory rate in vivo. Studies in the perfused liver showed this to be due to a decreased extraction efficiency during exogenous taurocholate loading.

High-performance liquid chromatographic determination of dimethylxanthine metabolites of caffeine in human plasma.

A normal-phase high-performance liquid chromatographic assay of caffeine and its metabolites, theophylline, theobromine and paraxanthine, in human plasma is described. The two internal standards ethyltheophylline and 1,3,7-trimethyluric acid are used simultaneously and cover the range of different polarities from caffeine to the three dimethylxanthines. Plasma (0.

High performance liquid chromatographic determination of moxalactam in human plasma and cerebrospinal fluid.

A sensitive and reproducible method for the measurement of moxalactam in plasma and cerebrospinal fluid is described. Plasma proteins were removed by precipitation with ice-cold methanol at pH 5.6 and centrifugation.

Identification of 27-nor-5 beta-cholestane-3 alpha,7 alpha,12 alpha,24 xi, 25 xi,26-hexol and partial characterization of the bile alcohol profile in urine.

The nature of the bile alcohols present in urine of an infant with neonatal cholestasis has been investigated. Urine was extracted with Sep-Pak C18 cartridges and a glucuronide fraction was isolated by ion exchange chromatography on Lipidex-DEAP. Following enzymatic hydrolysis and purification on Lipidex-DEAP, the bile alcohols were isolated by high performance liquid chromatography.