Basal production of pentane in expired gas from healthy humans.

BACKGROUND: Pentane in exhaled gas is often used as an index of lipoperoxidation, but today, there is no standardization for its measurement. In this study, with our technical experience, we determined basal production of pentane in healthy subjects, and we evaluated variability of pentane flow 1 month later. METHODS: 18 subjects inhaled hydrocarbon-free air (HCFA) in order to realize a lung washout. Ambient air and three samples (at T0, T10, T30 min) of expired gas were concentrated using a "trap-and-purge" procedure. For the analysis of pentane, an Al(2)O(3)/KCl plot column contained in a gas chromatograph equipped with a flame ionization detector was used. RESULTS: After 10 min of washout, mean (+/-SD) exhalation rate of pentane was 1+/-0.6 pmol min(-1) kg(-1). After 30 min of washout, mean (+/-SD) exhalation rate of pentane was 0.7+/-0.5 pmol min(-1) kg(-1). No significant difference in pentane flow was shown 1 month later for eight subjects who repeated the protocol. CONCLUSION: With our results and data of the literature, exhalation rates of pentane from healthy adults appear to range between 0.3 and 2 pmol min(-1) kg(-1). The variability of pentane flow 1 month later seems not very important.

Oxygen toxicity: simultaneous measure of pentane and malondialdehyde in humans exposed to hyperoxia.

In order to estimate cell damage caused by free radicals during oxygenotherapy, we investigated the time course of two markers of lipoperoxidation: pentane in breath and malondialdehyde (MDA) in blood during brief normobaric hyperoxia. Nine healthy subjects inhaled hydrocarbon-free air (HCFA) for 30 minutes, hydrocarbon-free 100% O2 (HCFO2) for 125 minutes and then HCFA for 70 minutes. After 15 minutes of washout with HCFA, ambient pentane was eliminated. After HCFO2, at T175 versus T30 (i.e., 145 min from the start of 100% HCFO2), pentane production increased (P< 0.05). MDA rose significantly at T155 min (i.e., 125 min from the start of HCFO2), versus T30 (P< 0.01). These results suggest that acute hyperoxia causes a moderate increase in lipid peroxidation in healthy subjects. The increase of pentane and MDA confirms that acute hyperoxia induces lipid peroxidation in healthy subjects.

A case of slow variant bisalbuminmia: study of its composition in amino acids.

The authors report an observation of slow variant bisalbuminemia. After electrophoretic separation of two varieties, the amino acid chromatographic analysis has permitted them to show that in the slow variant the molecule of albumin has undergone a substitution of several glutamic acid residues by lysine and of several alanine residues by proline. Such an alteration poses the problem of its effect on the antigenic specificity of the molecule and that of its mechanism of production.

Familial alpha-1-antitrypsin dificiency with Pi-Z and a new Pi-Gcler variant.

A case of familial deficiency in alpha-1-antitrypsin connected with Pi-0Z gene led to the finding of a new Gcler variant partly deficient, the electrofocusing pattern of which, located between that of G and I variants, was modified after neuraminidase digestion. A study of three generations shows that Gcler variant is transmitter according to an autosomally codominant mode. Moreover serum trypsin inhibitory capacity and concentration of ten proteins have been measured in this family. Except the known relation between serum alpha-1-antitrypsin level and trypsin inhibitory, capacity, only serum IgA showed a significant correlation with serum alpha-1-antitrypsin in the deficient group with Pi-Z allele.

[A rapid technique for extraction of urinary 17-kéto and 17-hydroxy-corticosteroids by chromatography (author's transl)]. / Technique d'extraction chromatographique rapide des 17-céto et des 17-hydroxy-corticostéroïdes urinares.

The extraction ot total urinary 17-keto and 17-hydroxy steroids has been effected by a rapid procedure involving pre-packed kieselguhr column chromatography. This work successively studies the correlation of this technique with the classical extraction by mechanical agitation (42 and 61 subjects), its reproducibility, repeatability and recovery of added internal standards. The proposed method seems convenient for routine clinical analysis.

[A tricuspid electrophoretic pattern: familial bisalbuminemia with monoclonal immunoglobulin]. / Un tracé électrophorétique tricuspide: bisalbuminémie familiale avec immunoglobuline monoclonale.

An association of a familial bisalbuminemia and a benign M component (IgG Kappa) in a healthy woman is described. Any connection between the two abnormalities is unlikely. However this rare association should be known for a better understanding of the striking features of its electrophoretic pattern.

[C-reactive protein and orosomucoid determinations in a neonatal pathology unit]. / Dosages de C-réactive protéine et d'orosomucoïde dans une unité de pathologie néonatale.

We report the result of CRP and ORM assays performed at the admission in the unit, in 157 neonates (NN). The NN were divided into 3 groups: 122 "controls" (group I), 21 having septicemia with or without meningitis but with symptoms of infection (group II), 16 having a positive blood culture without symptom of infection (group III). In group I, the CRP level does not depend on gestational age at birth, neither on the age at the assay. The level of ORM depends on both factors. Neonatal infection leads to a very significant rise of the CRP rate (often above 100 mg/l). The rise of ORM is not so dramatic. These data suggest that the assay of these two proteins are useful in the diagnosis of neonatal infection if they are performed together and at several times.