[Gas chromatographic-mass spectrometric analysis of gases produced by Trichomonas vaginalis in vitro]

Five strains of Trichomonas vaginalis were independently inoculated into Cysteine-Peptone-Liver infusion-Maltose medium (CPLM medium), and gases in the culture bottle were qualitatively analysed at five days after the inoculation by gas chromatography mass spectrometry (GC-MS). Methane, ethane and carbon dioxide were commonly found in the gases produced during the culture of Trichomonas vaginalis in vitro. Carbon monoxide was also found in the gases from 4 of 5 strains. Small amount of both ethylene and propane was also noted in 3 of 5 strains. These gaseous molecules were supposed to be produced by Trichomonas vaginalis in vitro, presumably by the catabolism of amino acids. It was also suggested that these gases, including methane, ethane, carbon dioxide, carbon monoxide, ethylene and propane, were responsible for the foamy discharge found in the vagina of patients with Trichomonas vaginalis.

Assessment of lipid peroxidation in newborn infants and rabbits by measurements of expired ethane and pentane: influence of parenteral lipid infusion

Peroxidation of the unsaturated fatty acid constituents of tissue is one proposed mechanism of in vivo oxidant damage. Products of unsaturated fatty acid peroxidation include the volatile hydrocarbons ethane and pentane. These volatile hydrocarbons are eliminated in expired air and reflect in vivo lipid peroxidation. Newborn infants excrete 16 pmol of ethane per kilogram body weight per minute and 15 pmol of pentane per kilogram body weight per minute. This compares with 1.4 pmol of ethane per kilogram body weight per minute and 1.3 pmol of pentane per kilogram body weight per minute in healthy adult men. Infants receiving total parenteral nutrition including intravenous lipid emulsion excrete more than 100 pmol of pentane per kilogram body weight per minute. Newborn rabbits, delivered at term, also excrete more pentane while receiving lipid emulsion infusion. In the newborn rabbit, the amount of pentane exhaled increases linearly with the dose of lipid emulsion. Blood and tissue thiobarbituric acid reactants are also increased in newborn rabbits after administration of lipid emulsion. These results indicate that lipid peroxidation is quantitatively greater in infants than in adult humans and can be significantly increased by parenteral administration of lipid emulsion.

Airborne transfer of contaminants in ventilated spaces

To assess the effectiveness of directional air flow and the influence of a disturbance such as opening and closing doors on the airborne transfer of contamination, the concentration of a tracer gas (ethane) was measured at various locations in a model consisting of four adjacent rooms between two corridors. Each room had two doors opening into the corridor. Ethane concentrations were measured as a function of pressure drop (0, +/- 0.005, +/- 0.01, and +/- 0.02 in. H2O) and time of door opening and closing (3, 6, and 9 sec). A hydrocarbon analyzer was used to measure the concentration of ethane. Contamination was transferred in the direction of decreasing static pressure and was proportional to the magnitude of the pressure differential. Opening and closing a door led to exchange of air between the spaces separated by the door regardless of the sign of the pressure differential that existed when the door was closed. The extent to which a space was contaminated by opening and closing a door was directly proportional to the time the door was open. Contaminant concentration differences between adjacent spaces were greatest when the connecting door was kept closed and the pressure differential was least. The findings indicate that modification of current practices may lead to improved protection of personnel, animals, and experiments from contamination.

Carbon tetrachloride metabolism in vivo and exhalation of volatile alkanes: dependence upon oxygen partial pressure

Metabolism of carbon tetrachloride in rats at atmospheric and reduced oxygen pressure has been determined indirectly by its disappearance from the inhaled air; it is inversely related to oxygen concentration and increases with decreasing partial pressure, as expected for reductive dehalogenation; oxygen partial pressure has been reduced to about a third of normobaric conditions. Concurrently exhalation of ethane and pentane as indication of lipid peroxidation has been monitored, showing a drastic increase when the oxygen partial pressure is reduced in the presence of carbon tetrachloride. Time course and duration of these processes indicate that the total metabolism of carbon tetrachloride is limited by the concomitant destruction of cytochrome P-450; also, oxidative destruction of polyunsaturated fatty acids apparently does not proceed beyond the end of metabolic activation of carbon tetrachloride. The molar ratios of the amount of metabolized carbon tetrachloride to the amounts of exhaled hydrocarbons lead to the same conclusion, namely that "lipid peroxidation" in this case does not proceed as an autocatalytic, self-propagating chain reaction.

Effect of alcoholic cirrhosis on ethane and pentane levels in breath

Lipid peroxidation can be monitored by measuring one or several highly volatile alkanes in exhaled air. The concentrations of ethane and pentane were determined in breath samples from patients with alcoholic and non-alcoholic cirrhosis as well as from healthy subjects. The greatest increase of exhaled pentane was found in 17 patients with alcoholic cirrhosis (2.85 +/- 2.37 pmol/ml) in comparison with 10 patients with non-alcoholic cirrhosis (0.71 +/- 0.33 pmol/ml) and 10 control subjects (0.59 +/- 0.41 pmol/ml). On the contrary, no significant difference was detected as far as exhaled ethane is concerned. These data suggest that: a) gas-chromatographic determination of exhaled pentane may play a significant role in detecting alcohol-induced liver disease; b) hepatic injury may be mediated by lipid peroxidation in these patients.

Lipid peroxidation in isolated rat hepatocytes measured by ethane and n-pentane formation

Isolated rat hepatocytes (1 X 10(7) cells/ml) were aerobically incubated in Eagle's Minimum Essential Medium which contained 2.0% albumin. As potential parameters of lipid peroxidation ethane and n-pentane formed were measured in samples obtained from the gas phase above the incubation mixture. 15-30 nmol ethane or n-pentane were produced by 10(7) hepatocytes within 90 min. Carbon tetrachloride (CCl4) or ADP-complexed ferrous ions stimulated ethane and n-pentane formation considerably, depending on the concentrations of the compounds. With CCl4 10(7) cells formed max 180 nmol ethane and 140 nmol n-pentane within 90 min incubation, whereas with Fe(II) max 130 nmol ethane and 220 nmol n-pentane could be detected. When n-pentane was added to the gas phase above the incubation mixture containing either medium or medium plus hepatocytes its amount decreased by 30% within the first 5 min of incubation. However, afterwards only minor amounts of n-pentane disappeared, even in the presence of hepatocytes. This indicates that n-pentane equilibrates with the cells suspension under the conditions used. Cell viability, as determined by the release of lactate dehydrogenase into the medium and by the uptake of trypan blue by the cells, and the recovery of the cells decreased only in presence of relatively high concentrations of CCl4, or Fe(II) respectively. However, a maximal effect on ethane and n-pentane formation was reached already with lower concentration.

Comparison of methods of assessment of metal-induced lipid peroxidation in isolated rat hepatocytes

There is some controversy about which method of assessment of lipid peroxidation in isolated hepatocytes is most appropriate. The present study was undertaken primarily to compare measurement of concentrations of thiobarbituric acid (TBA) reacting substances with measurement of ethane concentrations in the gas phase of the incubation flask as indicators of lipid peroxidation. Four metal salts, FeCl2, NaVO3, CdCl2, and MnCl2, were selected as agents that interact with the lipid peroxidation process. Furthermore, reduced glutathione (GSH) concentrations and enzyme leakage were assayed to determine whether there was a consistent pattern of interaction between lipid peroxidation and change in GSH concentrations and enzyme leakage. The effects of the metal ions on the concentration of TBA reactants estimated in the whole cell suspension and on the gaseous ethane concentration were similar. However, the assessment of TBA reactants was a little more sensitive, and ethane concentrations continued to climb with incubation time rather than leveling off as observed for TBA reactants. In general, the results of both assays were in good agreement. No consistent pattern of interaction between lipid peroxidation, GSH, and enzyme leakage was discernible in the results of the present study. It is suggested that perhaps the best approach to an experimental situation where lipid peroxidation is thought to be of central importance is measurement of both parameters, TBA reactants and ethane concentrations.

The measurement of lipid peroxidation in isolated hepatocytes

Different techniques for the measurement of lipid peroxidation in isolated hepatocytes have been compared. Measurements of ethane production, chemiluminescence and fluorescent products correlated extremely well with those of malondialdehyde formation. Of the five different techniques studied, measurements of ethane production and chemiluminescence were found to the the most sensitive indices of lipid peroxidation. Incubation of hepatocytes for up to 4 hr in the presence of ethylmorphine and aminopyrine, at concentrations known to stimulate H2O2 production, completely failed to increase the amount of chemiluminescence, malondialdehyde or ethane produced in these cells, indicating that the drug-stimulated production of H2O2 did not lead to an increased rate of lipid peroxidation, as cells under the experimental conditions employed. The relationship between lipid peroxidation, as measured by chemiluminescence and ethane production, and the cytotoxic effects of bromobenzene and carbon tetrachloride has also been studied. The results obrained further indicate that lipid peroxidation is an important even in carbon tetrachloride hepatotoxicity, but that it appears to be only a subsequent event in bromobenzene toxicity, possibly occurring only as a result of glutathione depletion and cell death.

Studies on biochemical effects of nitrogen dioxide. II. Changes of the protective systems in rat lungs and of lipid peroxidation by acute exposure

This work was done to clarify the relation between the change of lipid peroxidation and the protective systems in lungs after NO2 exposures. JCL:Wistar 8-wk-old male rats were exposed continuously to 10 ppm NO2 for 2 wk. Lipid peroxidation, measured by ethane exhalation in the breath of the rats and by the reaction of thiobarbituric acid with lung homogenates, increased to a maximum at 3 d after a decline at 1 d, and then returned to the initial level (of d 0). Activities of glutathione peroxidase (GPx), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), disulfide reductase (DSR), and superoxide dismutase (SOD) in the 105,000 X g supernatant of lung homogenates were depressed slightly at 1 d. Thereafter, they increased significantly to their maximum levels from 5 to 10 d, and these maximum levels were maintained until d 14. The pattern of change of these protective enzymes was symmetric to that of lipid peroxidation after 3 d. The order of the ratio of the increased value to the initial value was G6PD greater than DSR greater than 6PGD greater than GR greater than GPx greater than SOD. The time course of nonprotein sulfhydryls was similar to that of the protective enzymes. In contrast, the amounts of vitamin E increased to a maximum at 2 d and then returned to the initial level. The periodic change of vitamin E was similar to that of lipid peroxidation rather than that of the protective enzymes. These results suggest that the ability of the enzyme systems in lungs to protect against NO2 fluctuated in a complex manner and the activities of the protective enzymes varied inversely with lipid peroxidation.