Browsing by Author "Le Roux, M."
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- ItemChemical characterization of territorial marking fluid of male Bengal tiger, Panthera tigris(Springer Verlag, 2008-05) Burger, B. V.; Viviers, M. Z.; Bekker, J. P. I.; Le Roux, M.; Fish, N.; Fourie, W. B.; Weibchen, G.The territorial marking fluid of the male Bengal tiger, Panthera tigris, consists of a mixture of urine and a small quantity of lipid material that may act as a controlled-release carrier for the volatile constituents of the fluid. Using gas chromatography and gas chromatography-mass spectrometry, 98 volatile compounds and elemental sulfur were identified in the marking fluid. Another 16 volatiles were tentatively identified. The majority of these compounds were alkanols, alkanals, 2-alkanones, branched and unbranched alkanoic acids, dimethyl esters of dicarboxylic acids, γ- and δ-lactones, and compounds containing nitrogen or sulfur. Several samples of the marking fluid contained pure (R)-3-methyl-2-octanone, (R)-3-methyl-2-nonanone, and (R)-3-methyl-2-decanone, but these ketones were partly or completely racemized in other samples. The γ-lactone (S)-(+)-(Z)-6-dodecen-4-olide and the C8 to C16 saturated (R)-γ-lactones and (S)-δ-lactones were present in high enantiomeric purities. The chiral carboxylic acids, 2-methylnonanoic acid, 2-methyldecanoic acid, 2-methylundecanoic acid, and 2-ethylhexanoic acid were racemates. Cadaverine, putrescine, and 2-acetylpyrroline, previously reported as constituents of tiger urine, were not detected. The dominant contribution of some ketones, fatty acids, and lactones to the composition of the headspace of the marking fluid suggests that these compounds may be important constituents of the pheromone. Although it constitutes only a small proportion, the lipid fraction of the fluid contained larger quantities of the volatile organic compounds than the aqueous fraction (urine). The lipid derives its role as controlled-release carrier of the chemical message left by the tiger, from its affinity for the volatiles of the marking fluid. Six proteins with masses ranging from 16 to 69 kDa, inter alia, the carboxylesterase-like urinary protein known as cauxin, previously identified in the urine of the domestic cat and other felid species, were identified in the urine fraction of the marking fluid. © 2008 Springer Science+Business Media, LLC.
- ItemChemical characterization of the constituents of the aroma of honeybush, Cyclopia genistoides(Elsevier, 2008-01) Le Roux, M.; Cronje, J. C.; Joubert, E.; Burger, B. V.A high-capacity headspace sample enrichment probe (SEP) was used in conjunction with gas chromatography-mass spectrometry (GC-MS) to analyse the volatile organic compounds present in the aroma of dry or infused, unfermented (green) and fermented C. genistoides, one of the South African Cyclopia species from which a herbal tea, known as honeybush tea, is made. Seventy-seven compounds were identified in the volatile fraction of the aroma of dry, green C. genistoides, comprising, inter alia, a large number of saturated and unsaturated alcohols, aldehydes and methyl ketones. In the aroma of dry, as well as infused, fermented C. genistoides, 79 compounds were identified, 46 of which were terpenoids that were mostly present in much lower relative concentrations in the unfermented material. The methodology developed and the results obtained in the analysis of the aroma of C. genistoides provide a basis for ongoing comparative studies on the chemical composition of a series of prominent Cyclopia species with the view to developing a rapid screening device and protocol for honeybush tea evaluation. © 2007 SAAB.
- ItemDevelopment of second-generation sample enrichment probe for improved sorptive analysis of volatile organic compounds(Elsevier, 2011-03) Burger, B. V.; Le Roux, M.; Marx, B.; Herbert, S. A.; Amakali, K. T.The sample enrichment probe (SEP) has recently been introduced as a user-friendly and cost-effective method for the sorptive extraction of volatile organic analytes from gaseous and aqueous samples for GC and GC-MS analyses. In a further development of the SEP technique, thinner polydimethylsiloxane (PDMS) tubing on polyimide-coated fused silica, instead of stainless steel rods or stalks, were used to produce the second-generation SEPs. The new SEP does not require widening of the needle-guiding orifice of the septum cap and analytes are desorbed at a faster rate from the thinner sleeve, which reduces the risk of carry-over. The flowless period that was previously recommended for analyses of highly volatile analytes is made redundant by the faster desorption from the thinner sorptive medium. It was found that differences in the thermal histories of SEPs are not the cause of the high relative standard deviations (RSDs) reported in our first paper on the technique. Excellent reproducibility can be attained by careful handling and storing of loaded SEPs and by rigorously following a standardised analytical protocol. © 2011 Elsevier B.V.
- ItemMammalian exocrine secretions : X. Constituents of preorbital secretion of grysbok, Raphicerus melanotis(Springer Verlag, 1996-04) Burger, B. V.; Tien, F-C.; Le Roux, M.; Mo, W-P.Using electron impact and chemical ionization mass spectrometry with methane and nitric oxide as reactant gases in conjunction with mass spectral analysis of the dimethyl disulfide derivatives of unsaturated constituents, 51 compounds have been identified in addition to the compounds previously found in the preorbital secretion of the grysbok Raphicerus melanotis. The compounds identified are saturated, monounsaturated, and diunsaturated alcohols and formates, saturated and monounsaturated aldehydes, saturated carboxylic acids, γ- and δ-lactones, alkyl methyl sulfides, and β-hydroxyalkyl acetates. All of these compounds have unbranched structures. The constituent previously incorrectly identified as (Z)-5-tetradecen-1-ol, was found to consist of the coeluting (Z)-7- and (Z)-8-tetradecenols. © 1996 Plenum Publishing Corporation.
- ItemMammalian exocrine secretions IX : constituents of preorbital secretion of oribi, Ourebia ourebi(Springer Verlag, 1995-08) Mo, W.-P.; Burger, B. V.; Le Roux, M.; Spies, H. S. C.Using gas chromatography-mass spectrometry in conjunction with ancillary techniques such as chemical ionization with different reactant gases, determination of the position of double bonds by means of dimethyl disulfide derivatization, and finally gas chromatographic and mass spectrometric comparison with authentic synthetic material, 75 constituents were identified in the preorbital secretion of the male oribi,Ourebia ourebi. The secretion contains compounds with long-chain, unbranched structures similar to those found in many other preorbital secretions but with a finite volatility range, in contrast to the seemingly endlessly increasing chain lengths typical of other preorbital secretions.
- ItemMammalian exocrine secretions XI. Constituents of the preorbital secretion of klipspringer, Oreotragus oreotragus(Springer Verlag, 1997-10) Burger, B. V.; Yang, T-P.; Le Roux, M.; Brandt, W. F.; Cox, A. J.; Hart, P. F.The ketones 3-pentanone, 4-methyl-2-pentanone, 5-methyl-3-hexanone, 4-methyl-3-hexanone, and the esters ethyl propaneate, 2-methylpropyl acetate, ethyl 3-methylbutanoate, and 2-methylpropyl propanoate were identified as the only volatile organic constituents of the preorbital secretion of the klipspringer. Oreotragus oreotragus. These compounds are considerably more volatile than those found in the preorbital secretions of other antelopes belonging to the tribe Antelopini. More than 50% of the preorbital secretion consists of proteinaceous material, which probably acts as a controlled-release substance in retarding the evaporation of the volatile constituents of the secretion from territorial marks.
- ItemMammalian exocrine secretions XVII : chemical characterization of preorbital secretion of male suni, Neotragus moschatus(Springer Verlag, 2002-01) Stander, M. A.; Burger, B. V.; Le Roux, M.Gas chromatographic and gas chromatographic-mass spectrometric techniques were employed to identify 83 compounds, including alkanes, alkenes, aldehydes, 2-methylalkanes, carboxylic acids, 1-alkyl formates and alken-1-yl formates, benzoic acid, and cholesterol, in the preorbital secretion of the male suni, Neotragus moschatus. Dimethyl disulfide derivatization and lithium aluminum hydride reduction were used to determine the position of double bonds and to confirm the identity of the functional groups in some of the constituents of the secretion.
- ItemMammalian exocrine secretions. XII: Constituents of interdigital secretions of bontebok, Damaliscus dorcas dorcas, and blesbok, D. d. phillipsi(Springer Verlag, 1999-09) Burger, B. V.; Nell, A. E.; Spies, H. S. C.; Le Roux, M.; Bigalke, R. C.; Brand, P. A. J.In addition to the nine compounds identified in the interdigital secretion of the bontebok, Damaliscus dorcas dorcas, in a previous study, 76 compounds belonging to different compound types, were identified in the interdigital secretions of the bontebok and the blesbok, D. d. phillipsi. These compounds include alkanes, alcohols, aldehydes, ketones, fatty acids, terpenoids, γ-lactones, an isopropyl ester, long-chain hydroxyesters, 2- substituted pyridines, phenols, steroids, and dimethylsulfone. No qualitative differences were found between secretions from the two sexes or from animals from different habitats. Although no attempt was made to correlate territorial behavior or other behavioral phenomena with the qualitative composition of interdigital secretions from individual animals, available information seems to indicate that quantitative differences probably do not have a major semiochemical function. Only two species of bacteria, Bacillus brevis and Planococcus citreus, were found in the interdigital pouches of male and female members of the two subspecies, regardless of the habitat of the animals. B. brevis synthesized, among other unidentified constituents, (Z)-3-penten-2-ol, 2-hexanone, 2-octanone, 2-nonanone, tetradecanoic acid, pentadecanoic acid, heptadecanoic acid, octadecanoic acid, (Z)-9-hexadecenoic acid, and isopropyl hexadecanoate in vitro, while P. citreus produced, among others, the γ-lactones dodecan-4-olide and (Z)-6-dodecen-4-olide, which is one of the major constituents of the interdigital secretions of both subspecies. Some components of the interdigital secretions are not present in the interdigital glandular tissue, and the possibility is discussed that these compounds could be produced by microbiological activity in the interdigital pouch.
- ItemMammalian exocrine secretions. XIII: Constituents of preorbital secretions of Bontebok, Damaliscus dorcas dorcas, and Blesbok, D. d. phillipsi(Springer Verlag, 1999-09) Burger, B. V.; Nell, A. E.; Spies, H. S. C.; Le Roux, M.; Bigalke, R. C.The 42 compounds identified in the pale yellow preorbital secretions of the bontebok, Damaliscus dorcas dorcas, and the blesbok, D. d. phillipsi, include acetic acid, 2-methylbutanoic acid, (E)-2-methyl-2butenoic acid, benzoic acid, 4-hydroxybenzoic acid, saturated and unsaturated long-chain carboxylic acids, 4-hydroxybenzaldehyde, saturated and unsaturated, unbranched, long-chain alcohols and aldehydes, 2-heptanone, pentane, heptane, pepiritone, dimethylsulfone, isopropyl tetradecanoate, isopropyl hexadecanoate, hexadecyl acetate, δ-lactones, cholesterol, α-tocopherol, and squalene. Some qualitative and quantitative differences were found between the secretions of males and females of both subspecies.
- ItemPrevention of post-tonsillectomy pain with analgesic doses of ketamine(Health & Medical Publishing Group, 1987-12) Murray, W. B.; Yankelowitz, S. M.; Le Roux, M.; Bester, H. F.ENGLISH ABSTRACT: The prevention of postoperative pain in children who had undergone tonsillectomy was investigated in a double-blind trial. Ketamine (Ketalar; Parke-Davis) 0.5 mg/kg was given intravenously before the operation to 20 children and saline to a control group of 20 children. Premedication consisted of oral trimeprazine 4 mg/kg given 2 hours pre-operatively. The anaesthetic technique was standardised. There were no significant differences between the groups pre- or intra-operatively. Postoperatively there were significant differences in the measurement of pain but not in that of sedation. No hallucinations were encountered in those receiving ketamine. It is concluded that analgesic doses of ketamine are safe and effective.