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.

Patients admitted to emergency services for drunkenness: moderate alcohol users or harmful drinkers?

OBJECTIVE: Most of the patients admitted to hospital emergency services are drunk. Some of them may need specific treatment after acute intoxication remits. At present, treatment for alcoholism is offered to less than 5% of these patients. The authors evaluated the biological markers carbohydrate-deficient transferrin (CDT) and gamma-glutamyltransferase (GGT) in patients admitted for acute alcohol intoxication (per DSM-IV criteria) supported by blood alcohol assay. These tests distinguished between otherwise moderate alcohol users who were acutely intoxicated and harmful drinkers or alcohol-dependent patients. METHOD: The authors conducted an exhaustive survey 24 hours a day during 2 nonconsecutive months. The study involved 166 patients (124 men and 42 women) who were admitted for acute alcohol intoxication as a principal or additional diagnosis. Their blood was analyzed for alcohol, GGT, and CDT levels. The CAGE questionnaire was administered, and social and demographic data were collected. RESULTS: About 80% of the population studied displayed elevated GGT or CDT levels (65.7% had CDT levels >60 mg/liter; 41.6% had GGT levels >65 IU/liter). Less than 10% of the patients with acute alcohol intoxication revealed results in the normal range for both markers and a negative finding on the CAGE questionnaire. CONCLUSIONS: Patients admitted to emergency services with high blood alcohol levels should not be assumed to be moderate drinkers. Any drunkenness should be interpreted as a sign of likely harmful alcohol consumption or alcohol dependency requiring clinical and biological tests, including GGT and CDT assays. Specific treatment for alcoholism should be systematically offered to these patients.

Objective diagnosis of alcohol abuse: compared values of carbohydrate-deficient transferrin (CDT), gamma-glutamyl transferase (GGT), and mean corpuscular volume (MCV).

BACKGROUND: Alcohol abuse is roughly twice as common as alcohol dependence. Subjects with alcohol problems are usually diagnosed only when medical complications are present. Therefore, both doctors and patients need a method for early diagnosis of alcohol abuse. METHODS: The mean corpuscular volume, gamma-glutamyl transferase, and carbohydrate-deficient transferrin in alcohol abusers, alcohol-dependent patients, and "nonalcohol hospital" individuals were compared. RESULTS: For objective diagnosis of alcohol abuse, we found a sensitivity of 24%, a specificity of 96%, and a global predictive value of 63% for mean corpuscular volume; a sensitivity of 42%, a specificity of 76%, and a global predictive value of 61% for gamma-glutamyl transferase; and a sensitivity of 67%, a specificity of 97%, and a global predictive value of 84% for carbohydrate-deficient transferrin. CONCLUSIONS: Carbohydrate-deficient transferrin proves to be the best marker of alcohol abuse. It allows objective detection so that therapeutic action can be started early, which is easier and more effective than in alcohol dependence.

Usefulness of carbohydrate-deficient transferrin in alcoholic patients with normal gamma-glutamyltranspeptidase.

The biological diagnosis of alcoholism is conducted routinely by assay of gamma-glutamyltranspeptidase (GGT) and mean corpuscular volume (MCV). However, their low specificity and sensitivity have prompted research to find other more reliable parameters. Stibler showed an increase in desialylated transferrin [carbohydrate-deficient transferrin (CDT)] in alcoholic patients. The normal value of the serum CDT concentration is under 60 mg/liter; a value between 60 and 100 mg/liter indicates probable alcoholism, and a value > 100 mg/liter indicates a very high probability of alcoholism (specificity: 99%). Its sensitivity ranges from 60 to 91%, and its specificity ranges from 92 to 100%. Its half-life is 17 +/- 4 days. CDT is thus a useful laboratory marker, but its assay is costlier and more complex than that of GGT. This study concerns 31 alcohol-dependent patients as defined by DSM-IV, with GGT levels in the normal range. It evaluates CDT at day 0 and its time course after 15 days withdrawal. GGT and MCV were assayed concomitantly. Remarkably, the results show a sensitivity of 83.9 (26 positives of 31) in this particular population and a specificity of 92.2. The fall in CDT after 15 days withdrawal was 36%. CDT is thus a particularly useful marker for the diagnosis and follow-up of alcoholics with normal GGT levels.

[From sedimentation rate to inflammation profile]. / De la vitesse de sédimentation au profil inflammatoire.

The main biological sign of inflammation is an increase in erythrocyte sedimentation rate (ESR). However it can be falsely normal (polyglobulia, cryoglobulinemia, hemoglobinopathy) or spuriously high in the absence of inflammation (anemia, hypergammaglobulinemia). In cases of doubt, the acute phase reactants (APR) should be measured: C reactive protein (CRP), fibrinogen, haptoglobin, alpha 1 acid glycoprotein. They have different kinetics of variation and various degrees of increase (some--the so called "negative" proteins--actually decrease). Several pitfalls can be avoided if it is remembered that the APR themselves can be modified by causes other than inflammation: low fibrinogen in intravascular coagulation, very low haptoglobin in hemolysis, raised orosomucoide in renal insufficiency and elevated transferrin in iron deficiency. Furthermore liver insufficiency or leakage through the kidney or gut lesions can lower them. In some patients, the observed levels of APR are thus the result of opposite trends. In complex cases, these pathological mechanisms are more apparent on profiles which express the concomitant blood levels of several APR in a normalized or comparative manner. In medical practice, ESR serves first and foremost to detect an inflammatory syndrome. CRP is prominent among the APR because its changes show a great sensitivity, are independant of those of ESR and have a time course fitting closely that of the inflammatory processes. Profiles yield detailed information but rarely provide major evidence in the quest of a diagnosis or the choice of a treatment. Because of their cost they are to be used only in difficult cases.