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PubMed2006

Sources of insect and plant volatiles attractive to cottonwood leaf beetles feeding on hybrid poplar.

The cottonwood leaf beetle, Chrysomela scripta, is the most damaging insect affecting the production of Populus, an important source of sustainable forest products and biomass. Currently, there is no simple method for monitoring C. scripta populations, and nothing is known about potential chemical attractants for trapping. We conducted laboratory assays on sources of attraction to C. scripta adults. In olfactometer trials, beetles were attracted to volatiles released from conspecifics feeding on foliage. There was also significant, but lesser, attraction to odor from unwounded foliage, C. scripta alone, and frass. The latter two results indicate the presence of a pheromone. Wounding of foliage by C. scripta, but not by artificial means, enhanced its attractiveness compared to unwounded foliage, even when C. scripta by-products were removed. In direct comparisons, responses to odor from beetle-wounded foliage were not different from responses to odor from beetles feeding on foliage. We tested the attractiveness of volatiles emitted by adults feeding on foliage in the field using modified boll weevil traps. Results confirm that these volatiles are sufficient to increase trap catches in the field. Color is also important, with yellow baited traps catching more beetles than black baited. We propose that original landing by C. scripta is mediated by host odors and visual cues and that subsequent aggregation is enhanced by chemical cues associated with feeding by conspecifics. This may partially explain clustering in the field and likewise be incorporated into sampling schemes needed for integrated pest management.

Animals↗
PubMed1985

Volatile nitrites. Use and adverse effects related to the current epidemic of the acquired immune deficiency syndrome.

Early reports of the acquired immune deficiency syndrome (AIDS) in homosexual men suggested that the cause might be related to homosexual life-style practices, including use of recreational drugs. Inhalation of volatile nitrites is a possible contributing factor in AIDS because their pharmacologic properties lead to toxicity. Metabolism of N-nitroso compounds produces mutagens, teratogens, and potent carcinogens in 39 different animal species, and volatile nitrites have deleterious effects on human lymphocytes in vitro and in vivo. In relation to the current AIDS epidemic, the timing of production and sales of volatile nitrites for recreational use is the only new life-style factor that might answer the question "why AIDS now?" Prevalence of nitrite use among male homosexuals is very high, and almost every reported case of Kaposi's sarcoma during the past three years includes a history of prior nitrite use. The age of the group of patients in whom Kaposi's sarcoma and AIDS are developing is consistent with a cohort initially exposed seven to 10 years ago. Cessation of nitrite use could reduce the epidemic.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Is analysis of vaginal secretions for volatile organic acids to detect bacterial vaginosis of any diagnostic value?

A study was undertaken to determine which fermentation products in vaginal secretions serve as the best markers for bacterial vaginosis. Three categories of markers had been previously identified, but due to cost considerations it was necessary to accurately determine if analysis for all three were necessary. With the use of vaginal secretions from well-defined patient populations, we applied gas-liquid chromatography to test for both volatile and nonvolatile acid fermentation products. It was found that only the detection of nonvolatile acids was necessary, because no additional patients with bacterial vaginosis were identified by subsequent analysis of volatile acids. Routine analysis of volatile acids to identify patients with bacterial vaginosis is labor intensive and costly and had no clinical diagnostic value.

Acids↗
PubMed1989

Use of a volatile buffer system in ion-exchange high-performance liquid chromatography of oligonucleotides.

A volatile buffer has been adapted for use with ion-exchange high-performance liquid chromatography in the analysis and preparation of oligonucleotides. The system employs a commercial weakly basic anion-exchange column containing a DEAE-derivatized silica gel and eluted with a volatile buffer gradient of triethylamine acetate and acetonitrile. Nucleic acid digests and oligonucleotides synthesized by chemical or enzymatic methods can be analyzed or purified with nearly quantitative recovery following solvent volatilization.

Chromatography, DEAE-Cellulose↗
PubMed1985

Volatile carboxylic acid profiling in physiological fluids: direct injection into a gas chromatograph/mass spectrometer.

We present a procedure for the profiling of the volatile carboxylic acids and neutral compounds in blood or urine using the direct injection of the acidified sample into a gas chromatograph interfaced with a mass spectrometer by a jet separator. The non-volatile components remain at the head of the SP-1000 column while the volatile components move through the column. Up to sixty physiological samples can be analyzed before any degradation in mass spectrometer operating parameters is observed.

Carboxylic Acids↗
PubMed1990

Transient increases of intracellular Ca2+ induced by volatile anesthetics in rat hepatocytes.

The affects of volatile anesthetics on mobilization of intracellular Ca2+ was monitored in primary cultures of rat hepatocytes using the fluorescent Ca2+ probe Fura-2. The use of Fura-2 was limited by several factors which complicated the quantitative analysis of the results, such as: (i) a high rate of dye leakage; (ii) changes in the redox state of the hepatocytes which interfered with the fluorescence produced by the dye at various excitation wavelengths; (iii) compartmentalization of the dye producing high local intracellular concentrations; and, of particular importance for this study, (iv) enhanced photobleaching of the dye in the presence of halothane. To aid in the interpretation of the Fura-2 data, the Ca2(+)-sensitive photoprotein aequorin was also used to monitor changes in [Ca2+]i. The aequorin and Fura-2 techniques qualitatively yielded the same result, that the volatile anesthetic agents halothane, enflurane, and isoflurane induce an immediate and transient increase of [Ca2+]i. The durations of these transients were approximately between 5 and 10 min and were not related to any evident acute cell toxicity. The [Ca2+]i increases induced by the volatile anesthetic agents were dose-dependent, with halothane the most potent. The exact mechanism governing these increases in [Ca2+]i induced by these anesthetics in rat hepatocytes is unknown, but is likely to involve effects on both the cell surface membrane and endoplasmic reticulum components of the signal transducing system.

Aequorin↗
PubMed1985

Abusing the volatile organic chemicals.

Intentional inhalation of volatile organic chemicals is not a new phenomenon. It has existed since ancient times. Abusing household and other commercially available products, containing volatile organic solvents, has been recognized since the early 1950s. Products containing volatile organic chemicals include everything ranging from gasoline to paints, aerosolized foods, cosmetics, and other solvent-based household products. These products are easily available, legal, and usually inexpensive when compared to the alternative, illegal substances. While inhalant abuse is small when compared to the abuse of other substances, the problem can, in some cases, be fatal to the abuser. The public sector, industry, and government all are trying to find a solution. This paper reviews the history of perverted use of commercial products, the inhalant abuser, the signs and symptoms, the pharmacotoxicology, and the various approaches to solutions.

Animals↗
PubMed1983

An examination of human blood for the presence of volatile nitrosamines.

Human blood was examined for the presence of volatile nitrosamines. Nitrosamines were detected by chemiluminescence and mass spectrometry after separation from blood by distillation and solvent extraction. N-nitrosodimethylamine was detected in all but one of 51 blood samples taken from 23 different people, at concentrations from the detection limit (0.1 microgram/litre) to 1.4 microgram/litre with a mean concentration of 0.5 microgram/litre. N-Nitrosodiethylamine was detected in 11 samples, the detection limit being 0.1 microgram/litre. No other volatile nitrosamines were detected. After a test meal of bacon, spinach, bread and beer, the concentration of N-nitrosodimethylamine increased. There was no appreciable difference between the nitrosamine concentrations in the blood of laboratory workers and in the blood of other people. Salivary nitrite concentrations measured semi-quantitatively concurrently with blood sampling varied considerably but showed no apparent correlation with blood nitrosamine levels. Measurements in rabbits given a continuous infusion of N-nitrosodimethylamine gave a clearance rate approximately equal to the blood flow through the liver and a volume of distribution of 1.2 litre/kg body weight. By applying these results to man, the body burden after the meal was calculated as 40-50 microgram. This is substantially higher than the estimated weekly intake of volatile nitrosamines from food.

Adult↗
PubMed1989

Disruption of muscarinic receptor-G protein coupling is a general property of liquid volatile anesthetics.

The influences of 3 volatile anesthetics, chloroform, enflurane and isoflurane, on muscarinic acetylcholine receptors in rat brainstem were determined. Each of the volatile anesthetics increased [3H]methylscopolamine [( 3H]MS) binding affinity, but did not affect the number of [3H]MS binding sites. Carbamylcholine affinity for brainstem muscarinic receptors was not altered after equilibration of brainstem membranes with any of these anesthetics. The ability of guanine nucleotides to depress the high affinity binding of two agonists, carbamylcholine and [3H]oxotremorine-M, was decreased or eliminated after equilibration of brainstem membranes with any of the anesthetics. In each of these actions, these anesthetics resemble halothane and diethyl ether. These results indicate that interference with muscarinic receptor-G protein interactions is a common property of liquid volatile anesthetics and may represent a general mechanism for the disruption of signal transmission between cells during anesthesia.

Anesthetics↗
PubMed1985

Gas chromatographic-mass spectrometric analysis of volatile amines produced by several strains of Clostridium.

A gas chromatographic--mass spectrometric technique is proposed for the analysis of volatile amines which were isolated from Clostridium cultures by vacuum distillation and concentrated as hydrochloride salts. Headspace sampling after alkalinization of the salts under vacuum was the most suitable for subsequent gas chromatographic analysis. With ammonia-loaded helium as carrier gas, methylamines were separated on 4.8% PEG 2OM + 0.3% potassium hydroxide on Carbopack B, and other volatile amines on 28% Pennwalt 223 + 4% potassium hydroxide on Gas-Chrom R. Bacterial volatile amines (dimethylamine, trimethylamine, isobutylamine, 3-methylbutylamine, etc.) were detected with a flame-ionization detector and identified by gas chromatography--mass spectrometry in electron-impact and chemical ionization modes.

Amines↗
PubMed1994

Volatile anesthetics bidirectionally and stereospecifically modulate ligand binding to GABA receptors.

Pharmacologically relevant concentrations of volatile anesthetics can bidirectionally modulate radioligand binding to GABAA receptors. In mouse cerebral cortex, halothane (a prototypic volatile anesthetic) increased [3H]muscimol (a GABA receptor agonist) binding while inhibiting the binding of a GABA receptor antagonist ([3H]SR 95531). These bidirectional effects of inhalational anesthetics on ligand binding to GABA receptors are effected through changes in the Bmax with no significant alterations in the KD of these radioligands. Moreover, the concentration dependent, bidirectional modulation of radioligand binding to GABA receptors by volatile anesthetics exhibited stereoselectivity. Thus, (+)-isoflurane was about twice as potent as the (-)-enantiomer in enhancing [3H]muscimol binding and approximately 50% more potent as an inhibitor of [3H]SR 95531 binding, respectively. The demonstration of a bidirectional, stereospecific modulation of radioligand binding to GABA receptors by inhalational agents is consistent with the presence of specific recognition sites for inhalational anesthetics on the GABAA receptor complex.

Animals↗
PubMed1996

(Z,E)-alpha-farnesene--an electroantennogram-active component of Maladera matrida volatiles.

It has previously been shown in field-trapping experiments and laboratory olfactometer bioassays that virgin females of Maladera matrida Argaman (Coleoptera, Scarabaeidae) and their volatiles, both in the presence of food (cut peanut leaves), are efficient attractants for M. matrida males and females. In this study GC-EAD experiments using male antennae and GC-MS experiments revealed that (Z,E)-alpha-farnesene is an active component of M. matrida female volatiles. The identification and quantitive electrophysiological responses (EAG) of synthetic (Z,E)-alpha-farnesene were obtained with male and female antennae. It was also shown that (Z,E)-alpha-farnesene is not a component of the plant volatiles that serve as synergistic components of the mixture of attractants or of the source of food for M. matrida.

Animals↗
PubMed1995

Screening of volatile substances and determination of toluene (a thinner component) in the blood and urine in emergency medical care and autopsy cases by the pulse heating method.

Screening of volatile substances was performed by pulse heating gas chromatography - mass spectrometry (GC-MS) using a GS-Q column in 211 emergency medical care and 342 autopsy cases. At least 36 standard substances could be separately detected. Six kinds of volatile substances were screened in a total of 553 cases. Toluene and/or hippuric acid were detected in the blood and/or urine in respectively, 4 emergency medical care and 8 autopsy cases. There were 11 abusers (9 males and 2 females) in these 12 positive cases. The ages of the abusers ranged from 13-26 years. There was no particular pattern to the monthly frequency distribution of identification of thinner (toluene) abuse cases, which occurred throughout the year. It is believed that these data at least partly reflect the present status of thinner/glue abuse in Japan. We conclude that pulse heating GC-MS is useful in the screening and quantitative determination of volatile substances including toluene and other thinner/glue components.

Journal Article↗
PubMed2004

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses.

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project.

Aerobiosis↗
PubMed2006

Conditional volatility properties of sleep-disordered breathing.

The present paper investigates the conditional volatility properties of apneic electrocardiogram (ECG) sequences taken from the Physionet apnea database using a set of GARCH models. We discuss the theoretical justification of this approach in the light of the recent developments in heart rate volatility studies. The findings support the value of the Integrated GARCH(1,1) specification in fitting apneic ECG segments implying the presence of shocks to conditional volatility that persist over time. The ARCH(1) model was found superior in fitting normal ECG recordings. These findings provide an important indication to future research that GARCH models can be employed in the development of an apnea screening tool to be used in clinical settings.

Databases as Topic↗
PubMed2006

Validation of a method for acute and subchronic exposure of cells in vitro to volatile organic solvents.

In vitro assessment of organic solvents can be problematic as the volatile nature of these compounds makes maintaining a constant exposure level difficult. However, a stable exposure level must be maintained if reliable dose response data are to be obtained. Here we describe a gas-tight glass exposure system which allows prolonged exposure of cultured cells to constant concentrations of volatile organic solvents. The system permits convenient sampling of gas and liquid phases for reliable quantification of solvent concentration. We determined medium/air partition coefficients (K) for toluene, n-hexane and methyl ethyl ketone which can be used to calculate liquid phase solvent exposure levels in an in vitro system specifically designed for organic solvent exposure. Cultured cells were exposed to these compounds for five days and toxicity assessed by trypan blue exclusion. Headspace gas chromatography was used to determine K in RPMI-1640 and EMEM tissue culture medium at 37 degrees C. The presence of cells in the system at levels normally used in in vitro exposure systems did not significantly alter solvent partitioning. Equilibrium liquid phase solvent concentrations were measured by gas chromatography for two of the compounds to confirm that exposure levels calculated using K were correct. Results show that sub-chronic exposure to volatile organic solvents causes a dose dependent decrease in Jurkat T-cells and SH-SY5Y viability. Solvent potency increased with lipophilicity (n-hexane>toluene>MEK).

Acute Disease↗
PubMed2005

Codon volatility does not reflect selective pressure on the HIV-1 genome.

Codon volatility is defined as the proportion of a codon's point-mutation neighbors that encode different amino acids. The cumulative volatility of a gene in relation to its associated genome was recently reported to be an indicator of selection pressure. We used this approach to measure selection on all available full-length HIV-1 subtype B genomes in the Los Alamos HIV Sequence Database, and compared these estimates against those obtained via established likelihood- and distance-based comparative methods. Volatility failed to correlate with the results of any of the comparative methods demonstrating that it is not a reliable indicator of selection pressure.

Biological Evolution↗
PubMed2000

NMR study of volatile anesthetic binding to nicotinic acetylcholine receptors.

New lines of evidence suggest that volatile anesthetics interact specifically with proteins. Direct binding analysis, however, has been largely limited to soluble proteins. In this study, specific interaction was investigated between isoflurane, a clinically important volatile anesthetic, and membrane-bound nicotinic acetylcholine receptors (nAChRs) from Torpedo electroplax, using (19)F nuclear magnetic resonance spectroscopy and gas chromatography. The receptors were reconstituted into 1, 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipid vesicles. After correcting for nonspecific partitioning into the lipid, the equilibrium dissociation constant, K(d), of isoflurane binding to nAChR at 15 degrees C was found to be 0.36 +/- 0.03 mM. This value is within the clinically relevant concentration range of the agent. Based on the receptor concentrations in the vesicle suspension assayed by the bicinchoninic acid method and the fraction of bound isoflurane, X(b), determined by gas chromatography, an estimate of an average of 9-10 specifically bound isoflurane molecules can be made for each receptor, or two for each subunit. Upon binding, the transverse relaxation time constant (T(2)) of (19)F resonance of isoflurane is decreased by nearly three orders of magnitude, indicating a dramatic reduction in the mobility of specifically bound isoflurane. Kinetic analysis reveals that the off rate of binding, k(-1), is 1.7 x 10(4) s(-1). The on rate, k(+1), can thus be calculated to be approximately 4.8 x 10(7) M(-1) s(-1), suggesting a nearly diffusion-limited association. This is in contrast to anesthetic binding to a soluble protein, bovine serum albumin (BSA), where k(+1) and k(-1) are at least an order of magnitude slower. It is concluded that the presence of lipids may be critical for the correct evaluation of binding kinetics between volatile anesthetics and neuronal receptors.

Anesthetics, Inhalation↗