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PubMed1995

Testing human hair and urine for anhydroecgonine methyl ester, a pyrolysis product of cocaine.

A method using gas chromatography coupled to mass spectrometry for the determination of the cocaine (COC) pyrolysis product, anhydroecgonine methyl ester (AEME), in urine and hair is described. The same procedure allows the simultaneous determination of COC, benzoylecgonine (BZE), ecgonine methyl ester, and cocaethylene. The assay involves acid hydrolysis for hair, deuterated internal standards, a three-step liquid-liquid extraction, and derivatization with N,O-bis(trimethylsilyl) trifluoroacetamide plus 1% trimethylchlorosilane. Detector responses for analytes were linear over the concentration ranges of 0.2-50 ng/mg and 10-2000 ng/mL for hair and urine, respectively. Artifact formation of AEME during the injection was less than 1%. AEME was tested in 65 and 81 cases for hair and urine, respectively, where COC or BZE or both tested positive. Concentrations of AEME ranged from 0.2 to 2.4 ng/mg (n = 7) and from 4 to 226 ng/mL (n = 12) in hair and urine, respectively. Its presence was observed in few cases, clearly indicating that COC smoking is not frequent in France.

Cocaine↗

PubMedDate not supplied

Determination of pyrolysis products of smoked methamphetamine mixed with tobacco by tandem mass spectrometry.

This study examines the pyrolysis products of smoked methamphetamine mixed with tobacco that was trapped with a C8 adsorbent cartridge and then detected by gas chromatography-tandem mass spectrometry. According to the results, the mainstream smoke contains 2-methylpropyl-benzene, 2-chloropropyl-benzene, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, 3-ethyl-phenol, methamphetamine, dimethylamphetamine, hydroquinone, 3-methyl-5-(1-methylethyl)-methylcarbamate phenol, N-methyl-N-(2-phenylethyl)-acetamide, 4-(3-hydroxy-1-butenyl)-3,5,5-trimethyl-2-cyclohexene-1-one, propanoic acid, N-acetylmethamphetamine, phenyl ester, and furfurylmethylamphetamine. In addition, the compounds in sidestream smoke are 2-propenyl benzene, phenylacetone, methamphetamine, dimethylamphetamine, benzyl methyl ketoxime, 3,4-dihydro-2-naphthalenone, N-folmyamphetamine, N-acetylamphetamine, bibenzyl, N-folmylmethamphetamine, N-acetylmethamphetamine, N-propionymethamphetamine, and furfurylmethylamphetamine. Moreover, the presence of methamphetamine promotes the oxidation of the tobacco components.

Drug Interactions↗

PubMed1988

Activating mutations in human c-Ha-ras-1 gene induced by reactive derivatives of safrole and the glutamic pyrolysis product, Glu-P-3.

Foci of transformed NIH3T3 cells were observed after transfection of plasmids containing the c-Ha-ras-1 protooncogene modified in vitro either with the 3-N,N-acetoxyacetyl derivative (N-AcO-AGlu-P-3) of the mutagenic L-glutamic acid pyrolysis product 3-amino-4,6-dimethyldipyrido-[1,2-a:3',2'-d]imidazole (Glu-P-3) or with 1'-acetoxysafrole (AcO-S), a reactive derivative of the carcinogen safrole. DNA isolated from these foci were used in a second round of transfection, and the DNA obtained from the secondary transformants was analysed to determine the nature of mutations responsible for activating the protooncogene. The polymerase chain reaction method was used to amplify sequences of the gene likely to contain activating mutations, and these regions were then subjected to selective hybridization with specific oligonucleotides to locate and identify the point mutations. Five out of six transformants induced by N-AcO-AGlu-P-3 contained mutations at codon 61. Three of the codon 61 mutations were at the first base and the other two were at the third base, all were GC----TA transversions. Two AcO-S-induced transformants contained a GC----TA transversion, in one case at the first base of codon 61, in the other at the first base of codon 12. Another AcO-S-induced transformant, and the sixth transformant induced by N-AcO-AGlu-P-3 were apparently not mutated in codon 12, 61 or 117. Both N-AcO-AGlu-P-3 and AcO-S react predominantly with guanine residues in DNA, and all the mutations identified here were at GC base pairs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

The food pyrolysis product IQ enhances its own activation.

The metabolic activation of the food pyrolysis product 2-amino-3-methylimidazo (4,5-f) quinoline (IQ) to mutagenic intermediates in the Ames test was studied using hepatic activation systems from control and IQ-treated rats. Hepatic S9 preparations from IQ-treated rats were more efficient than control in converting IQ to mutagens. An increase was also seen when isolated microsomes were employed as activation systems but this was less pronounced. The microsome-mediated mutagenicity of IQ was potentiated by addition of the cytosolic fraction from control and IQ-treated rats, the latter being more effective. It is concluded that IQ, at the doses employed in the present study, enhances its own bioactivation to genotoxic metabolites by stimulating both its microsomal and cytosolic metabolism.

Animals↗

PubMed1981

Identification of modified nucleosides in intact transfer ribonucleic acid by pyrolysis-electron impact-collisional activation mass spectrometry.

A novel mass spectrometric method has been developed for the detection and identification of dihydrouridine, ribothymidine, 4-thiouridine, and 7-methylguanosine in Escherichia coli tRNAs. The method utilizes (a) Pyrolysis-Electron Impact-Mass Spectrometry (PYEIMS), a procedure which releases the purine and pyrimidine bases from the intact, underivatized tRNA molecule. The mass spectrum exhibits intense peaks for the bases deriving from the common nucleosides in tRNA as well as peaks of much lower intensity at mass values expected for the bases from modified components known to be present in the tRNA; and, (b) Collisional Activation Mass Spectrometry (CAMS), a technique which permits the isolation of a single ion species from a complex mass spectrum. Subsequent fragmentation of that species yields a characteristic collisional activation spectrum. Such analyses of the ion species that were presumed to originate from H2Urd, rThd, 4SUrd, and 7MeGuo in the tRNA were used to define the structure and, thus, the identity of each component. Attributes of the PYEICAMS technique are that (a) precise structural elucidation of minor nucleosides present in tRNAs at the 1 - 4% level is obtained; (b) the high order of sensitivity allows the analysis to be done on microgram amounts of tRNA; and (c) there is no requirement for enzymatic or chemical hydrolysis of the tRNA or for subsequent chromatographic separation methods.

Escherichia coli↗

PubMed1997

Negative inotropic effect of methylecgonidine, a major product of cocaine base pyrolysis, on ferret and human myocardium.

This study examined the physiological effects and potential mechanisms of action of methylecgonidine (MEG), the major pyrolysis product from smoking "crack cocaine," on cardiac function. Ferret right ventricular papillary muscles and human ventricular trabeculae were isolated and placed in a physiological solution at 30 degrees C containing 2.5 mM Ca2+ and stimulated at 0.33 Hz. MEG decreased peak tension and peak intracellular Ca2+ transients in a concentration-dependent manner (10 microM-1 mM). The negative inotropic effect (NIE) of MEG was reversible by atropine (1 microM). Atropine shifted the concentration-response curve of MEG rightward (pA2 = 9.17) similar to that of carbachol (pA2 = 8.70). With prior addition of histamine (1 microM) and Ca2+ (4.5 mM) in equiinotropic concentrations, MEG and carbachol decreased contractility to a greater extent in the histamine-stimulated muscles. To clarify whether the treatments altered responsiveness of the contractile elements to Ca2+, the effect of 2,3-butanedione monoxime (BDM), an agent that interferes with the interaction of actin and myosin, was tested after prior addition of histamine or increased Ca2+. No differential effect occurred. Moreover, the nitric oxide synthase inhibitor NG-nitro-L-arginine methylester (L-NAME; 0.1 mM), lessened the NIE of MEG compared with prior (pre-L-NAME) values. Furthermore, in human ventricular trabeculae (n = 7), MEG exhibited an NIE that was also reversible by atropine. We concluded that the NIE of MEG is caused by decreased calcium availability; the effect is not the result of a local anesthetic action but is mediated by stimulation of cholinergic receptors. This effect is potentiated by the nitric oxide pathway.

Adjuvants, Anesthesia↗

PubMed2001

Cerumen composition by flash pyrolysis-gas chromatography/mass spectrometry.

OBJECTIVE: To assess the chemical composition of cerumen by flash pyrolysis-gas chromatography/mass spectrometry. STUDY DESIGN: Collected earwax specimens were fractionated into residue and supernatant by means of deoxycholate. This natural bile acid produces significantly better disintegration of earwax in vitro than do presently available ceruminolytic preparations, and also has demonstrated excellent clinical results in vivo to date. PATIENTS: The sample for analysis was obtained from a patient with clinical earwax impaction. RESULTS: The supernatant is composed of simple aromatic hydrocarbons, C5-C17 straight-chain hydrocarbons, a complex mixture of compounds tentatively identified as diterpenoids, and steroids, in particular cholesterol. The residue, on the other hand, produced simple aromatic compounds (including benzenes, phenols, and benzonitriles), C5-C25 straight-chain hydrocarbons, greater relative quantities of nitrogen compounds and phenol, and lesser importance of the (tentatively identified) diterpenoids. CONCLUSIONS: Through the use of the detergent deoxycholate, squalene and a tentatively identified diterpenoid were revealed to be present in a free, unbound state, whereas some steroids and hydrocarbons appeared to be bound to a macromolecular structure by nitrogen linkages or other bonds. Additionally, this study reintroduces detergents as a viable method of earwax removal, specifically the bile acids.

Carbon↗

PubMed1978

Use of canonical variates analysis in differentiation of bacteria by pyrolysis gas-liquid chromatography.

Low-resolution pyrolysis gas-liquid chromatography (p.g.l.c.) can differentiate genera of aerobic food spoilage bacteria. Multivariate statistical techniques were applied but neither principal components nor furthest neighbour cluster analysis produced a consistent differentiation although both confirmed the reproducibility of p.g.l.c. When the distance between genera was redefined in terms of Mahalanobis D2- a generalized concept taking into account scatter around the mean-good differentiation was observed and could be displayed graphically by plotting the genus group means relative to the first two canonical variate axes. The coefficients of the canonical variates provide a strategy for discriminating between the genus groups. Some practical problems in the identification of unknowns using this technique are discussed.

Bacteria↗

PubMed1981

Pyrolysis mass spectrometry: a new method to differentiate between the mycobacteria of the 'tuberculosis complex' and other mycobacteria.

Pyrolysis mass spectrometry (p.m.s.) was applied to differentiate 91 coded mycobacteria as belonging to either the 'tuberculosis complex' (M. tuberculosis, M. bovis and M. bovis BCG) or to other species of Mycobacterium. Strains were analysed in batches; in each batch three strains each of M. tuberculosis, M. bovis and M. bovis BCG were included as references. Mass spectra were evaluated by computerized multivariate analysis. A 92% positive correlation with classical identification tests was found (2.2% false negative, 5.5% false positive). Approaches for further improvement of this score are indicated. High speed and complete automation of sample analysis, as well as computerized data-processing, make p.m.s. a potential tool for routine application. Sample transfer from peripheral laboratories to a p.m.s. facility is easy, as samples can be sterilized before shipping.

Hot Temperature↗

PubMed1981

Reproducible pyrolysis-gas chromatography of micro-organisms with solid stationary phases and isothermal oven temperatures.

Eight solid stationary phases were examined for their suitability for pyrolysis-gas chromatography (Py-GC) of micro-organisms. With temperature programming these phases offered little advantage over the traditional liquid phase Carbowax 20M, but at an isothermal analysis temperature of 100 degrees C their use solved many technical problems. Pyrograms were produced containing small numbers of baseline-resolved peaks which eluted within 8 to 25 min. Four to six specimens per hour could be examined with two pyrolysers attached to one chromatograph oven. When a control organism was used to derive normalized results, pyrograms were reproducible with a second column and a second pyrolyser, suggesting that inter-laboratory reproducibility may be possible. Five different bacterial genera were well discriminated and some differentiation was achieved between different isolates of Streptococcus mutans, but similarity between pyrograms with was unrelated to orthodox taxonomic grouping. The best discrimination was achieved with Chromosorb 104, followed by Chromosorb 101 and Tenax-GC. With solid phases and isothermal oven temperatures Py-GC is a promising technique for microbial identification.

Bacteria↗

PubMed1983

Classification and identification of Mycobacterium africanum by pyrolysis mass spectrometry.

Pyrolysis mass spectrometry was used to classify and identify strains of Mycobacterium africanum and of M. tuberculosis, M. bovis and M. bovis BCG. The multicharacter mass pyrograms were evaluated by computerized data handling procedures that were suited for classification and identification. The results revealed considerable heterogeneity among the African strains, which was shown to be linked to the geographic distribution of the strains. On the basis of a routine mass spectrometric identification key the African strains were identified without exception as belonging to, what is referred to as the 'Tuberculosis complex' (i.e. the clinically relevant group formed by strains of M. Tuberculosis, M. bovis and M. bovis BCG). Classification of the strains by means of discriminant analysis indicated an intermediate clustering for the majority of the African strains and overlap for some African strains with in particular M. bovis. It was concluded that from the mass spectrometric data a species status for the group of African strains was not justifiable.

Africa↗

PubMed1983

Differentiation between gram-negative anaerobic bacteria by pyrolysis gas chromatography of lipopolysaccharides.

Lipopolysaccharides extracted by phenol-water from nine strains of Gram-positive anaerobic bacteria (Bacteroides. Fusobacterium and Veillonella), have been examined by means of pyrolysis gas chromatography. Lipopolysaccharides were fragmented into a group of low molecular weight components and four characteristic high molecular fractions probably consisting of hydrocarbons from the lipid part of the material. The latter fractions were specific for each of the genera tested. At the species level characteristic differences were also found although a limited number of strains were tested. Due to the high reproducibility of the technique, the potential of using the method in differentiating Gram-negative anaerobic bacteria was indicated.

Bacteroides↗

PubMed1988

Pyrolysis mass spectrometry as a method for inter-strain discrimination of Candida albicans.

A claim that Candida albicans strains NCPF 3153 and B311 were identical was investigated. Authentic strains were shown to be distinct (P less than 0.1%) by pyrolysis mass spectrometry (PyMS). Of twelve strains, provided as clones of NCPF 3153, seven were authenticated, one yielded an equivocal result and four were distinct from both NCPF 3153 and B311. Of eight B311 clones, six were authenticated and two yielded equivocal results. Although five non-C. albicans yeast strains were identified as distinct from B311 and NCPF 3153, Torulopsis glabrata NCPF 3240 was identified as B311, and one clinical isolate of C. albicans as NCPF 3153. This could be explained by the specificity of the mathematical analysis for discrimination between the authentic strains.

Candida albicans↗

PubMed1988

An assessment of taxonomic congruence between DNA-DNA hybridization and pyrolysis gas-liquid chromatographic classifications.

The existence of subgroups within Bacillus megaterium has been reported previously on the basis of DNA-DNA hybridization and DNA base composition studies. In this study the strains used to define these subgroups have been reanalysed by pyrolysis gas-liquid chromatography. The resultant two-group classification of the test strains was directly comparable with that obtained from the previous nucleic acid analyses at the between-group level. However, comparisons of the test strains at the within-group level proved less successful.

Bacillus megaterium↗

PubMed1983

Identification of staphylococci by pyrolysis gas-liquid chromatography.

The identification of bacteria by pyrolysis gas-liquid chromatography (PGLC) was evaluated with the genus Staphylococcus. A matrix containing the characteristics of seven species of Staphylococcus was constructed from the results obtained with 42 named strains identified by biochemical methods. An identification program based upon this database was evaluated in tests with 100 isolates of catalase-positive oxidase-negative gram-positive cocci identified by biochemical and PGLC systems. Agreement between the two systems was 90%. Pure cultures of unknown isolates were identified within 30 min by PGLC using a microcomputer data acquisition and analysis program. A taxonomic analysis of the data is presented, and methods for quality control of PGLC, prolongation of column life, and data analysis are described and discussed.

Analysis of Variance↗

PubMed1989

Identification of viridans streptococci by pyrolysis-gas chromatography.

An isothermal method of pyrolysis-gas chromatography (Py-GC) was used for the identification of viridans streptococci. Pyrograms from 104 reference strains were subjected to a discriminant analysis to produce classification coefficients for the identification of 74 test organisms. Five groups representing recognised species were discriminated but Streptococcus milleri strains could not be distinguished from S. sanguis. If S. milleri and S. sanguis are regarded as a single pyrogroup, only three strains out of 74 were incorrectly identified by Py-GC. A multidimensional scaling analysis of the Py-GC data produced a similar species grouping, but this statistical method was less satisfactory for pyrogram data than discriminant analysis. While Py-GC was moderately successful for the identification of viridans streptococci, this study indicated that the technique has limited use in diagnostic medical microbiology because it is time-consuming and lacks flexibility.

Chromatography, Gas↗

PubMed1989

Epidemiological typing of Streptococcus pyogenes by pyrolysis mass spectrometry.

Strains of Streptococcus pyogenes from an outbreak of infection on a burns unit (15), a collection of routine isolates from another hospital(12) and isolates from a national survey of throat infections in children in the community(4) were examined blind by pyrolysis-mass spectrometry (Py-MS). The outbreak strains (M22 T12) previously found to give identical typing results in conventional tests, formed a closely similar cluster and were distinct from other hospital and community strains. One hospital and one community strain were loosely associated with this cluster. Another cluster comprised six antibiotic-susceptible strains and two community strains. Six strains did not fall within the clusters; four were antibiotic-resistant strains isolated in hospital, one an antibiotic-resistant strain isolated in the community, and one a susceptible hospital strain. Results show that Py-MS is a potentially valuable method for rapid comparison of strains in studies of infection.

Bacterial Typing Techniques↗

PubMed1990

A pyrolysis-mass spectrometry study of Corynebacterium spp.

Clinical (66) and collection (38) strains of Corynebacterium spp., including C. jeikeium and CDC group D2, and of Listeria monocytogenes were examined. Conventional characters used in species identification were assessed by a microbiochemical method, and pyrolysis-mass spectrometry (Py-MS) was performed with a Horizon Instruments PYMS 200X. Classification based on Py-MS data yielded clusters that corresponded with species identification and classification groups from conventional data. One small group of clinical strains, homogeneous in conventional tests and Py-MS, comprised isolates from sputum samples from patients undergoing ventilation; they were similar to collection strains of C. renale and C. striatum; the latter species has been implicated in chest infection. Another group, similar to C. minutissimum in both systems, comprised clinical strains isolated from urogenital specimens. L. monocytogenes strains were clearly distinct from Corynebacterium spp. Groups comprising CDC D2 strains and C. jeikeium were resolved, and were similar to other Corynebacterium spp. Two collection strains of C. xerosis were distinct in conventional tests and Py-MS.

Bacterial Typing Techniques↗