Electron capture gas-liquid chromatography of short chain acids as their 2,2,2-trichloroethyl esters

Biochemical effects and monitoring of exposure of rats to 4-methylcyclohexyl-1,6-dicarboxylic acid anhydride vapour

Male Wistar rats exposed to 5, 10 or 20 p.p.m. 4-methylcyclohexyl-1,6-dicarboxylic acid anhydride vapour for 2-11 weeks showed dose-dependent blood anhydride concentrations. The maximum concentrations were found after two weeks. At five exposure weeks, they were smaller but they did not decrease further thereafter. The change was coincident with increased epoxide hydrase activity in liver. The excretion of 4-methylcyclohexyl-1,6-dicarboxylic acid was detected in the urine. The excretion was linearly related to the exposure in specimens collected during the 10th and 11th week. Brain acetylcholinesterase activity was transiently inhibited by the exposure at the two higher doses while decreased enzyme activity in the isolated spinal cord axons was only found after 11 weeks. This change was simultaneous with increased creatine kinase activity in the cerebellar homogenate. In the occupational setting, acetylcholinesterase activity might only be significantly inhibited in lungs because of the low exposure levels.

Gas chromatography in the identification of microorganisms and diagnosis of infectious diseases

Gas-liquid chromatography (GLC) continues to find increasing applications in the characterization of microorganisms and the diseases associated with them. GLC has been used to characterize microorganisms through qualitative and quantitative analyses of cellular structural components and soluble extracts and metabolic by-products. Chromatographic patterns, or fingerprints, can be used to differentiate between very closely related microorganisms, even strain differences, and provides a potentially powerful tool for future taxonomic studies and more precision in definitive microbial classification. However, the most valuable use of GLC is in the identification of disease through patterns obtained by direct analysis of body fluids. Chromatographic fingerprints of microbial metabolites and compounds associated with the host response to infection and even noninfectious disease can be used to develop relatively simple GLC diagnostic methods. These methods are specific, sensitive, and rapid. This review examines the use of GLC for identification of infectious diseases through the analysis of body fluids, spent culture media, and cellular materials and suggest other clinical areas where its diagnostic potential has yet to be developed.

Electron capture gas-liquid chromatographic study of metabolites produced by some arthritic transudate-associated organisms in vitro and in vivo in rabbit models

Computerized, frequency-pulsed, modulated electron capture gas-liquid chromatography was used to study the acid metabolites produced in vitro in fetal calf serum and in vivo in an animal chamber model. Several strains of Diplostreptococcus agalactiae, Propionibacterium acnes, Staphylococcus aureus, and Streptococcus serogroups A, B, and G were studied. All of these organisms have been reported to be associated with arthritic transudates in humans. Metabolites were detected by this method from derivatized extracts of both spent fetal calf serum and chamber fluids. Since there was little host response to the organisms cultured in the chambers, it is highly probable that the products detected represent metabolites produced in an in vivo type of environment. The metabolic patterns were reproducible and exhibited many similarities in vitro and in vivo. Production of the acids detected was reproducible, and these acids were useful identification markers. The data support published reports (J. B. Brooks, C. C. Alley, and J. A. Liddle, Anal. Chem. 46: 1930-1934, 1974; J. B. Brooks, G. Choudhary, R. B. Craven, D. Edman, C. C. Alley, and J. A. Liddle, J. Clin. Microbiol. 5:625-628, 1977; J. B. Brooks, R. B. Craven, A. R. Melton, and C. C. Alley, in H. H. Johnson and W. B. Newson, ed., Second International Symposium on Rapid Methods and Automation on Microbiology, 1976; J. B. Brooks, R. B. Craven, D. Schlossberg, C. C. Alley, and F. M. Pitts, J. Clin. Microbiol. 8:203-208, 1978; J. B. Brooks, D. S. Kellogg, C. C. Alley, H. B. Short, and H. H. Handsfield, J. Infect. Dis. 129:660-668, 1974) that bacterial metabolites might be detectable in diseased body fluids. The growth characteristics of the organisms in the animal model and fetal calf serum are discussed, and a moderately priced computer for performing data manipulations is evaluated.

Possible use of frequency-pulse-modulated electron capture gas-liquid chromatography to identify septic and aseptic causes of pleural effusions

Frequency-pulse-modulated electron capture gas-liquid chromatography was used in conjunction with appropriate derivatization procedures to obtain chromatograms from extracts of pleural effusions. These chromatograms were used to rapidly classify the various types of pleural effusions. With this method we have been able to distinguish among a limited number of effusions caused by congestive heart failure, Mycobacterium tuberculosis, and some other types of bacterial empyemas and pleural effusions.

Quantitative analysis of trifluoroacetic acid in body fluids of patients treated with halothane

A simple procedure for the quantitative analysis of trifluoroacetic acid (TFA) in urine and serum from patients narcotized with halothane is described. This involves addition of sodium hydroxide to the body fluid, evaporation of the aqueous phase and esterification of TFA in concentrated sulphuric acid with 2,2,2-trichloroethanol. The gaseous phases above the reaction mixture were then analyzed by gas chromatography with a nickel-63 electron-capture detector. The detection limit was 1 microgram of TFA per mililitre of body fluid (200 microgram of body fluid are analysed) and the relative standard deviation was +/-6%. Patients treated with ethrane, another commercial anaesthetic, did not produce any detectable TFA.

Rapid diagnosis of lymphocytic meningitis by frequency-pulsed electron capture gas-liquid chromatography: differentiation of tuberculous, cryptococcal, and viral meningitis

Cerebrospinal fluid specimens from patients with tuberculous (17 cases), cryptococcal (15 cases), and viral (14 cases) meningitis were analyzed by frequency-pulsed electron capture gas-liquid chromatography and mass spectrometry. Compounds that disappeared after therapy were found to be present in each of these specimens and were not detected in controls. They occurred in repetitive patterns such that these three types of meningitis could be rapidly distinguished. The compound associated with tuberculous meningitis has been tentatively identified. These finding have implications for rapid diagnosis, pathophysiological studies, and possible new therapeutic approaches.