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PubMed1990

Identification of carcinogenic tryptophan pyrolysis products in human bile by high-performance liquid chromatography.

The carcinogenic tryptophan pyrolysis products 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) have been demonstrated to be present in human bile through use of a high-performance liquid chromatography (HPLC) method. The method consists of the acid-induced release of the carcinogens from bile components and their extraction with methylene chloride and subsequent quantification by HPLC. In seven subjects who had received catheterization of the bile duct and external biliarydrainage, the average amounts of Trp-P-1 and Trp-P-2 excreted daily in the bile were 408 fmol/day (n = 7) and 864 fmol/day (n = 7), respectively. In one subject, furthermore, significant daily changes of these carcinogen levels in bile and plasma were confirmed during 2 weeks of observation. These results indicate that one of the excretory pathways of these carcinogens is via bile. Our data also may suggest that Trp-P-1 and Trp-P-2 are derived from everyday foods.

Bile↗
PubMed1981

Quantification of phencyclidine in mainstream smoke and identification of phenylcyclohex-1-ene as pyrolysis product.

Parsley cigarettes containing [3H]phencyclidine were machine smoked, and the mainstream smoke was trapped in glass wool filters. Radioactivity was extracted from these filters with chloroform. The average recoveries of radioactivity were 76, 85, 70, and 69% for cigarettes containing 3, 10, 30, and 50 mg of [3H]phencyclidine hydrochloride, respectively. TLC and GLC-mass spectrometry were employed to identify and quantify compounds in the filter extracts. Approximately one-half of the recovered radioactivity represented a pyrolysis product, phenylcyclohex-1-ene. Formation of this product involved loss of piperidine from phencyclidine. Piperidine, which was not radiolabeled, also may appear in smoke intact. The remainder of the radiolabeled material represented unchanged phencyclidine. Therefore, the percentage of [3H]phencyclidine delivered was approximately 40% of the amount smoked. This result was independent of puff frequency and quantity of phencyclidine hydrochloride smoked over the range tested. The [3H]phencyclidine delivery was compared to the quantities of [3H]-delta 9-tetrahydrocannabinol and [3H]nicotine delivered in mainstream smoke. The recovery of unchanged [3H]-delta 9-tetrahydrocannabinol from placebo marijuana cigarettes injected with a solution containing 3 mg of delta 9-tetrahydrocannabinol was 60%. Tobacco cigarettes injected with [3H]nicotine yielded 70% unchanged nicotine in mainstream smoke.

Cannabis↗
PubMed1979

Induction of enzyme-altered islands in rat liver by tryptophan pyrolysis products.

Two new gamma-carboline derivatives, 3-amino-1,4-dimethyl-5H pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H pyrido[4,3-b]indole (Trp-P-2), isolated from the pyrolysis products of tryptophan, were found to be potent mutagens. When weanling rats were injected with Trp-P-1 and then given diet containing phenobarbital, they developed enzyme-altered islands in the liver. Since these islands are considered to be formed by immediate progeny of "initiated cells" and cell precursors in hepatocarcinogenesis, Trp-P-1 may well be carcinogenic in rat liver.

Adenosine Triphosphatases↗
PubMed1978

Pyrolysis gas-liquid chromatography applied to a study of variation in Arthroderma tuberculatum.

Replicates of whole colonies of four species of closely related dermatophytes were analyzed by pyrolysis gas-liquid chromatography (PGLC). The four species included fifteen strains of Arthroderma tuberculatum, and two strains each of A. benhamiae, Nannizzia gypsea and N. incurvata. Individual peaks on different pyrograms were identified as homologous with the aid of internal markers by the superimposition of pyrograms. The peak height data extracted from the pyrograms of the fungal samples were analyzed to compute average similarities between pairs of pyograms. The average was calculated with each peak weighted equally, and log weighted for its information content. The results of the cluster analyses of proximities were generally similar. Most, but not all, replicates of each strain were similar enough to be clustered together. Some strains belonging to the same species were also similar enough to be grouped in one cluster. Other strains of a single species varied sufficiently to be put in separate clusters. The nearest neighbour to each OTU (pyrogram) was always a replicate of the same strain.

Ascomycota↗
PubMed1985

Investigation by pyrolysis mass spectrometry, phage pattern and plasmid analysis of staphylococci that have reverted from 'L'-phase to bacterial phase.

No major differences have been found in series of Staphylococcus aureus strains which reverted from 'L'-phase, either by pyrolysis mass spectrometry or by phage-typing or sensitivity testing. In 'L'-phase they have been subcultured for a long time or transformed/reverted many times into/from 'L'-phase. Plasmids were lost during transformations/reversions, but there was some difference between the tetracycline-connected plasmids on the one hand and the erythromycin-connected ones on the other.

L Forms↗
PubMed1980

Acetylcholine in human placenta. Identification by pyrolysis gas chromatography/mass spectrometry and tissue levels following different modes of delivery.

Extracts from human term placentae were analyzed by pyrolysis gas chromatography (GC) combined with mass spectrometry. The only choline ester of carbonic acid whose presence could be unequivocally established was acetylcholine (ACh). The mass spectrum of its demethylated tertiary derivative dimethylaminoethyl acetate (nor-ACh) agreed entirely with that of authentic pyrolyzed ACh. The concentrations of ACh were determined in placentae obtained after vaginal or Caesarean delivery to investigate the claim that the latter resulted in tissue with higher concentrations of ACh-like activity presumably because ACh was not expended during labor and delivery. No differences inACh content were found with GC analysis. The ACh concentrations were 102 +/- 17 (n=8) nmoles/g fresh tissue (vaginal delivery) vs. 105 +/- 16 (n=6) nmoles/g (Caesarean section). The fetal membranes (amnion and chorion) and the umbilical cord contained no ACh under the analytical conditions with a limit of sensitivity of 200 pmoles ACh.

Acetylcholine↗
PubMed1979

The organic composition of the Allan Hills carbonaceous chondrite (77306) as determined by pyrolysis-gas chromatography-mass spectrometry and other methods.

The amino acid composition and the pyrolyzable organic content of the Antarctic Allan Hills meteorite (ALHA 77306.9 and ALHA 77306.17) was examined. The pyrolysis products are very similar to those of the Murchison meteorite. The identified amino acids are present at quite low levels, they are racemic and are structurally similar to those observed in the Murchison meteorite. This indicates the possible chemical synthesis of these compounds in the meteorite parent body. The Allan Hills meteorite is not detectably contaminated.

Amino Acids↗
PubMed1987

Carbohydrate profiling of bacteria by gas chromatography-mass spectrometry: chemical derivatization and analytical pyrolysis.

Carbohydrate profiling by gas chromatography-mass spectrometry is a powerful tool for the identification and detection of bacteria. Its increasing applicability in the microbiology laboratory is illustrated by three examples. In the first, differentiation of legionellae by their sugar composition was determined with alditol acetate derivatization followed by selected- ion monitoring. In the second example, a carbohydrate pyrolysis product from Streptococcus agalactiae was used to differentiate group B streptococci from other Lancefield groups after direct sampling from culture plates. The third example employed the carbohydrates rhamnose and muramic acid as chemical markers for the direct detection of bacterial cell wall degradation products in mammalian tissues. The analysis of carbohydrate markers for bacteria by gas chromatography-mass spectrometry has great potential for use in clinical identification of isolated bacteria as well as in the rapid diagnosis of bacterial infections without prior culture.

Animals↗
PubMed1983

Metabolic activation of Trp-P-2, a tryptophan-pyrolysis mutagen, by isolated rat hepatocytes.

Metabolic activation of a tryptophan-pyrolysis product, 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), by isolated rat hepatocytes was studied. The substrate (Trp-P-2) disappearance by hepatocytes from untreated rats was slow, but enhanced by 3-methylcholanthrene (MC) pretreatment of rats. The covalent binding of Trp-P-2 to cellular macromolecules was detected in hepatocytes from untreated rats. The amount of covalent binding of Trp-P-2 to protein and RNA was greater than that to DNA. The covalent binding to Trp-P-2 to DNA, RNA and protein in hepatocytes from untreated rats was about 5-10 times less than that in hepatocytes from MC-pretreated rats. 7,8-Benzoflavone strongly inhibited the substrate disappearance and the binding of Trp-P-2 to DNA in hepatocytes from MC-pretreated rats. These results indicate that Trp-P-2 is metabolically activated by the P-448 type of cytochrome P-450 which is induced by MC. Diethylmaleate enhanced by about 50% the binding of Trp-P-2 to DNA in hepatocytes from MC-pretreated rats. On the other hand, cysteine inhibited the binding of Trp-P-2 to DNA with a concomitant reduction in the accumulation of the active metabolite, N-hydroxy-Trp-P-2 (N-OH-Trp-P-2). Sulfhydryl compounds seemed to play important roles in the detoxification of Trp-P-2.

Animals↗
PubMed1988

1,5-Anhydro-beta-L-arabinofuranose from pyrolysis of plant cell wall materials (biomass).

Three types of agricultural waste material having a significant content of L-arabinose have been subjected to mild, vacuum pyrolysis, and yields of 1,5-anhydro-L-arabinofuranose (1) determined. In corn bran, approximately 40% of the L-arabinose is converted into 1, and this conversion is increased to 78% when the bran is subjected to prior acid washing. The inner and outer barks of ponderosa pine give approximately 30% conversion of their L-arabinose content into 1, but orange peel gives only 9% conversion. A mechanism is postulated involving pyrolytic scission of pendant L-arabinofuranose units from polysaccharides, with cyclization to produce 1.

Agriculture↗
PubMed1991

Characterisation of polysaccharides by in-source pyrolysis positive- and negative-ion direct chemical ionisation-mass spectrometry.

Series of oligosaccharide ions have been generated from a range of polysaccharides by the application of in-source pyrolysis mass spectrometry, using both ammonia positive-ion chemical ionisation and negative-ion chlorine-nucleophilic-addition ionisation. Glucans with alpha-(1----6), beta-(1----6), alpha-(1----4), beta-(1----4), beta-(1----3), and beta-(1----2) linkages were studied, together with pentosans, xyloglucans, and an arabinogalactan. The series of ions correspond to intact, desorbed oligosaccharides with a terminal anhydro-sugar unit, and to similar oligosaccharides with attached sugar ring-cleavage fragments. The ions generated are dependent on the position of the linkage and ring size, and retain significant information on the structure of the original polysaccharide.

Carbohydrate Sequence↗
PubMed1981

Metabolic activation of glutamic acid pyrolysis products, 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole and 2-amino-dipyrido[1,2-a:3',2'-d]imidazole, by purified cytochrome P-450.

Metabolic activation by cytochrome P-450 of glutamic acid pyrolysis products, 2-amino-6-methyldipyrido(1,2-a:3',2'-d)imidazole (Glu-P-1) and 2-amino-dipyrido(1,2,-a:3',2'-d)imidazole (Glu-P-2), to mutagenic metabolites was studied using Salmonella typhimurium TA98 as a tester strain. Cytochrome P-450, NADPH-cytochrome P-450 reductase and NADPH were essential requirements for the activation of these compounds. Of the four forms of cytochrome P-450 examined, polychlorinated biphenyls (PCB) P-448 and 3-methylcholanthrene (MC) P-448 purified from liver microsomes of rats treated with a PCB mixture and MC, respectively, showed high activity in the activation of both Glu-P-1 and Glu-P-2. The presence of three metabolites from Glu-P-1 or Glu-P-2 was demonstrated by high performance liquid chromatographic (HPLC) analysis. Among the metabolites of Glu-P-1, two metabolites were mutagenic without any further enzymatic activation. In accordance with the results of a mutation assay, PCB P-448 also exhibited higher activity to form the major mutagenic metabolite of Glu-P-1. The major active metabolite of Glu-P-1 was characterized as N-hydroxy-Glu-P-1 by chemical analysis using oxidizing and reducing reagents and by mass spectrometry.

Animals↗
PubMed1981

Simultaneous measurement of acetylcholine and choline in brain by pyrolysis-gas chromatography-mass spectrometry.

Pyrolysis-gas chromatography and chemical ionization mass fragmentography were combined to develop a specific, simple and rapid method for simultaneously measuring endogenous and stable isotopic variants of acetylcholine and choline with a detection limit of approximately 10(-12) mol. The recovery and reproducibility of the method are excellent, and the method is suitable for measuring acetylcholine and choline in discrete regions of rat brain and to measure incorporation of choline into acetylcholine, both of which uses are demonstrated. This method affords easy analysis of 40 samples in a working day. The new technique used to extract compounds from tissues and the modified gas flow arrangement may be useful to measure other compounds as well.

Acetylcholine↗
PubMed1987

Detection of Trp-P-1 and Trp-P-2, carcinogenic tryptophan pyrolysis products, in dialysis fluid of patients with uremia.

In order to estimate the exposure levels of mutagenic and carcinogenic heterocyclic amines in humans, we developed a high-performance liquid chromatography method to detect 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) in dialysis fluid of patients with uremia. Using this methods, dialysis fluid of 12 patients who had received hemodialysis treatment or continuous ambulatory peritoneal dialysis was examined. Trp-P-1 was detected in dialysate of all uremic patients (727 +/- 282 pmoles, n = 12). In patients who had been treated with continuous ambulatory peritoneal dialysis, the average amount of Trp-P-1 found in whole dialysate (6 l) per day was 710 +/- 203 pmoles (mean +/- S.D., n = 8). Moreover, Trp-P-2 could be detected in 5 out of 12 patients (206 +/- 85 pmoles, n = 5). These results indicate that patients with uremia are actually exposed to carcinogenic tryptophan pyrolysis products. The average exposure level of Trp-P-1 in uremic patients apparently exceeded 710 pmoles (150 ng) per day.

Carbolines↗
PubMed1989

Exposure level monitor of a carcinogenic glutamic acid pyrolysis product in rabbits.

In order to determine a suitable indicator for estimating the exposure levels of the dietary carcinogen 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), a carcinogenic glutamic acid pyrolysis product, the levels of Glu-P-1 bound to blood components were monitored for 8 weeks by a high-performance liquid chromatography method after the dietary carcinogen was administered as single oral doses (0.2-50 mg) to rabbits. In all rabbits dosed with Glu-P-1, Glu-P-1 in erythrocytes was detectable even on day 42 after administration. Glu-P-1 in plasma disappeared faster than did Glu-P-1 in erythrocytes. Glu-P-1 levels in rabbit hemoglobin were linearly related to administered doses at all points of time investigated. The results suggest that Glu-P-1 covalently bound to hemoglobin is very suitable for monitoring long-term exposure levels.

Administration, Oral↗
PubMed1992

Pyrolysis mass spectrometry of Listeria monocytogenes isolates from sheep.

Forty-eight isolates of Listeria monocytogenes from sheep and silage, involved in five small outbreaks of listeriosis, were compared by pyrolysis mass spectrometry (PyMS). The method clustered isolates from single animals, and showed that epidemiologically associated isolates were closely related to each other. PyMS is a simple technique capable of analysing large numbers of samples daily, and its application in veterinary studies should help to elucidate the epidemiology of listeriosis.

Animals↗