Assay of the concentration and 13C enrichment of acetate and acetyl-CoA by gas chromatography-mass spectrometry.

We present two techniques for determining the concentration and 13C enrichment of acetate in biological fluids. After the sample has been spiked with an internal standard of [2,2,2,2H3,1-13C]acetate, acetate is first enzymatically converted to acetyl-coenzyme A, which is chemically converted to acetylglycine. The latter is analyzed by gas chromatography-mass spectrometry, either as a methyl ester by positive chemical ionization or as a pentafluorobenzyl ester by negative chemical ionization.

Prenatal diagnosis for the unstable CTG repeat sequence in myotonic dystrophy: a retrospective study in a French family.

The results of DNA analysis for the unstable CTG repeat are reported in a french family of myotonic dystrophy. This retrospective study confirms results obtained previously with a linked DNA marker, using the CTG repeat DNA sequence in the same family. The demonstrated possibility of predicting phenotype as well as genotype in prenatal diagnosis is important for such a disorder, were subjects may be severely affected.

The presence of epithelioid granulomas in hepatitis C virus-related cirrhosis.

We examined surgical liver specimens from 52 patients with hepatitis C virus-related cirrhosis. All patients underwent orthotopic liver transplantation at Paul Brousse Hospital. They were found to be seropositive for antibodies to hepatitis C virus by second-generation testing (RIBA 2, Ortho Diagnostic Systems Inc, Westwood, MA).

Metabolism of 2,3-butanediol stereoisomers in the perfused rat liver.

The identification of 2,3-butanediol in sera of alcoholics led to the hypothesis that it may be a specific marker of alcohol abuse. We have investigated the metabolism of the individual isomers of 2,3-butanediol (2R,3R-, 2S,3S-, meso-2,3-butanediol and racemic 2,3-butanediol) in perfused livers from fed rats. Rates of uptake of the isomers decrease in the order (i) 2R,3R-, (ii) meso-, (iii) 2S,3S-2,3-butanediol.

Altitudinal variation in the response of the vegetation to Late-glacial climatic events in the northern French Alps.

Pollen and macroscopic plant remains were studied at eight neighbouring sites, in order to define Late-glacial vegetational history in the northern French Alps. Local pollen assemblage zones are described and indicate that the main elements of vegetational history combine the features of adjacent regions. Herb pollen assemblages are similar to those recorded in the Swiss Late-glacial, whereas the early occurrence of shrubs and trees is typical of the southern French Alps.

Identification of serine 624, aspartic acid 702, and histidine 734 as the catalytic triad residues of mouse dipeptidyl-peptidase IV (CD26). A member of a novel family of nonclassical serine hydrolases.

Dipeptidyl-peptidase IV (DPP IV, CD26, EC 3.4.14.

Determination of the 13C-labeling pattern of glucose by gas chromatography-mass spectrometry.

We developed a gas chromatography-mass spectrometric method which allows to determine the complete 13C-labeling pattern of glucose. The method uses four derivatives of glucose (methyloxime trimethylsilyl, bisbutylboronate acetate, aldonitrile pentaacetate, and permethyl) and selective analysis of fragment ions retaining specific carbon atoms. The technique was tested by analyzing glucose from rat livers perfused with various 13C tracers.

Assay of the acetyl-CoA probe acetyl-sulfamethoxazole and of sulfamethoxazole by gas chromatography-mass spectrometry.

We present gas chromatographic-mass spectrometric assays for (i) the concentration of sulfamethoxazole and (ii) the concentration and molar percentage enrichment of acetyl-sulfamethoxazole in biological fluids. The compounds are extracted with ethyl acetate, derivatized with either diazomethane or pentafluorobenzyl bromide, and analyzed by gas chromatography-mass spectrometry. Quantitation is achieved using internal standards, [2H4]sulfamethoxazole and acetyl-[2H4]sulfamethoxazole.

Determination of the 13C-labeling pattern of glutamate by gas chromatography-mass spectrometry.

We present a simple technique for determining the 13C-labeling pattern of glutamate by gas chromatography-mass spectrometry. Glutamate is derivatized with dimethylformamide dimethyl acetal (Methyl-8R). The dimethylaminomethylene methyl ester derivative of glutamate yields fragment ions that allow calculation of 13C enrichment on each carbon.

Production of interleukin 8 (IL-8) by cord blood mononuclear cells induced by Listeria monocytogenes.

The defective ability of human newborns to mobilize phagocytes to the site of infection led us to examine the ability of cord blood mononuclear cells to secrete interleukin-8, a major neutrophil chemotactic factor, in response to stimulation with Listeria monocytogenes. Adult or cord blood mononuclear cells were incubated with L. monocytogenes for varying lengths of time, and IL-8 was measured in the culture supernatants by the enzyme-linked immunosorbent assay (ELISA).

Diversity of chromosomal genetic elements and gene identification in antibiotic-resistant strains of Streptococcus pneumoniae and Streptococcus bovis.

Antibiotic-resistant Streptococcus pneumoniae (26 strains) and Streptococcus bovis (28 strains), devoid of R plasmids, were examined for DNA-DNA homology to Tn916 and Tn3701. Tn916-like structures were found in 17 S. pneumoniae and 21 S.

Rates of gluconeogenesis and citric acid cycle in perfused livers, assessed from the mass spectrometric assay of the 13C labeling pattern of glutamate.

Absolute rates of gluconeogenesis and of the citric acid cycle were assessed in livers isolated from 24-h starved rats, perfused with physiological concentrations of [3-13C]lactate and [3-13C]pyruvate +/- 0.2 mM octanoate. Calculations are based on (i) the 13C-labeling pattern of glutamate determined by gas chromatography-mass spectrometry combined with isotopomer analysis, (ii) substrate balance, and (iii) equations developed by Magnusson et al.

Lipid composition of leprosy-derived corynebacteria, a distinct group of corynebacteria, and of a reference Corynebacterium.

Leprosy-derived corynebacteria (LDC) are diphtheroid organisms isolated from leprosy patients and previously characterized by DNA and cell wall analysis. Three groups of LDC components of taxonomic value, glycolipids, and phospholipids and cell-wall-bound lipids were analyzed in comparison with those of a reference strain C. hoffmannii (CH).

Prenatal diagnosis of hereditary amyloidosis in a Portuguese family living in France.

Portuguese type amyloidosis is an autosomal dominant condition caused by a mutation in the transthyretin gene. This mutation can be detected directly by the presence of a restriction site for NsiI. We report here our first prenatal diagnosis for this condition performed by chorionic villus sampling, polymerase chain reaction, and restriction enzyme digestion.

Fractionation by SFE and microcolumn analysis of the essential oil and the bitter principles of hops.

Supercritical fluid extraction (SFE) is evaluated and optimized for the enrichment and fractionation of the essential oil and the bitter principles of hops (Humulus lupulus), both of which contribute to the flavor of beer. Profiles of the essential oil of different hop varieties are compared. The bitter principles, the humulones and lupulones, are analyzed by miniaturized liquid chromatography (micro-LC) and by micellar electrokinetic chromatography (MEKC).

Y-chromosome-specific haplotypes of Jews detected by probes 49f and 49a.

A sample of Ashkenazic and Sephardic Jews has been studied with respect to haplotypes at the 49f-49a Y-specific DNA probes. Only seven haplotypes were found in Jews, three of them (VII, VIII, and XI) being the most widespread. Haplotype distribution in the European non-Jewish population is different.

Simple method for quantifying alpha-tocopherol in low-density+very-low-density lipoproteins and in high-density lipoproteins.

We assessed the distribution of alpha-tocopherol in serum lipoprotein samples after separating the lipoprotein fractions by either sequential ultracentrifugation or selective precipitation with sodium phosphotungstate-magnesium chloride reagent. alpha-Tocopherol concentrations were determined by reversed-phase high-performance liquid chromatography. After ultracentrifugation, we found that in men, low- and very-low-density serum lipoproteins (LDL-VLDL) contained 53.

Metabolism of R- and S-1,3-butanediol in perfused livers from meal-fed and starved rats.

The metabolism of millimolar concentrations of R- or S-1,3-butanediol has been studied in perfused livers from fed and starved rats. Protocols were designed to measure in the same experiment (i) uptake of the diol, (ii) the contribution of the diol to ketogenesis, (iii) the contribution of the diol to total fatty acid plus sterol synthesis, and (iv) conversion of S-1,3-butanediol into S-3-hydroxybutyrate. Our data show that R- and S-1,3-butanediol are taken up by the liver at the same rate.

Human trophoblast cells express CD4 and are permissive for productive infection with HIV-1.

The European collaborative study of HIV-infected pregnant women in Europe now indicates a 13% risk of fetal HIV infection (originally thought to be about 30%, and possibly higher in some countries). Several reports suggest trans-placental passage. However, the detailed mechanisms associated with such vertical transmission have not yet been clarified.