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At least 127 records · Page 7Linked to original sources
PubMed1986

The metabolism of 1-phenyl-2-(N-methyl-N-furfurylamino)propane (furfenorex) in the rat in vivo and in vitro.

The metabolism of 1-phenyl-2-(N-methyl-N-furfurylamino)propane (furfenorex) was studied in the rat in vivo and in vitro. Nine metabolites with only traces of the unchanged drug were obtained from urine after oral administration of furfenorex to rats. The major metabolite was an acidic compound, isolated and identified as 1-phenyl-2-(N-methyl-N-gamma-valerolactonylamino)propane. Amphetamine, methamphetamine and their hydroxylated metabolites were excreted as minor metabolites. Metabolites excreted in two days after administration of the drug amounted to about 20% of dose. The acidic metabolite, a major metabolite in vivo, was not detected after incubation of furfenorex with rat-liver microsomes. The major metabolic routes of furfenorex in vitro were N-demethylation and N-defurfurylation which produced 1-phenyl-2-(N-furfurylamino)propane (furfurylamphetamine) and methamphetamine, respectively. The formation of furfurylamphetamine and methamphetamine were catalysed by rat-liver microsomes supplemented with NADPH and O2, and were inhibited by either SKF 525-A or CO. The formation of both metabolites were inhibited by 2-methyl-1,2-bis-(3-pyridyl)-1-propanone (metyrapone), but not by 7,8-benzoflavone. They were enhanced by pretreatment of rats with phenobarbitone, but not with 3-methylcholanthrene. These data suggested that N-demethylation and N-defurfurylation of furfenorex were mainly mediated by cytochrome P-450 but not cytochrome P-448.

Animals↗
PubMed1986

Synergistic activity of doxorubicin and the bisdioxopiperazine (+)-1,2-bis(3,5-dioxopiperazinyl-1-yl)propane (ICRF 187) against the murine sarcoma S180 cell line.

The bisdioxopiperazine (+)-1,2-bis(3,5-dioxopiperazinyl-1-yl)-propane (ICRF 187) abrogates doxorubicin cardiotoxicity in every mammalian species tested, but its effect on doxorubicin antitumor activity remains poorly understood. In order to better define the anthracycline-bisdioxopiperazine interaction, the ability of murine sarcoma S180 cells to form colonies in soft agar and their capability to proliferate in microtiter wells were assayed after exposure to drug at varying doses and schedules. Incubation of cell suspensions for 1 h with doxorubicin, 0.1 microgram/ml, with or without (+)-1,2-bis(3,5-dioxopiperazinyl-1-yl)propane, 80 micrograms/ml, produces additive cytotoxicity for the combination. Prolonged incubation (24 h) with the same drugs produces synergistic cytotoxic and antiproliferative effects at 1- and 2-log order reductions in dose. These studies indicate that the antineoplastic activity of the single agents doxorubicin and (+)-1,2-bis(3,5-dioxopiperazinyl-1-yl)propane is enhanced when the drugs are used in combination, and that this phenomenon is highly dose and schedule dependent.

Animals↗
PubMed1983

[Inhibition of bone tissue formation by propane-2,2-diphosphonate].

Among other diphosphonates here described propane-2,2-diphosphonate displays specific effects on bone-turnover. In contrast to other diphosphonates propane-2,2-diphosphonate inhibits especially different enzymes of growing bone and therefore inhibits formation of bone. The indication for the clinical use follows from that effect: pathologic states with increased bone formation may be treated by application of propane-2,2-diphosphonate.

Animals↗
PubMed2002

Determination of the carbon kinetic isotope effects on propane hydroxylation mediated by the methane monooxygenases from Methylococcus capsulatus (Bath) by using stable carbon isotopic analysis.

Authentic propane with known position-specific carbon isotope composition at each carbon atom was subjected to hydroxylation by the particulate and soluble methane monooxygenase (pMMO and sMMO) from Methylococcus capsulatus (Bath), and the corresponding position-specific carbon isotope content was redetermined for the product 2-propanol. Neither the reaction mediated by pMMO nor that with sMMO showed an intermolecular (12)C/(13)C kinetic isotope effect effect on the propane hydroxylation at the secondary carbon; this indicates that there is little structural change at the carbon center attacked during formation of the transition state in the rate-determining step. This finding is in line with the concerted mechanism proposed for pMMO (Bath), and suggested for sMMO (Bath), namely, direct side-on insertion of an active "O" species across the C-H bond, as has been previously reported for singlet carbene insertion.

2-Propanol↗
PubMed1991

Routine cryofixation of plant tissue by propane jet freezing for freeze substitution.

Cryofixation and freeze substitution methods were developed for ultrastructural studies of cells in complex plant tissues. Leaf tissues and root tips of tobacco (Nicotiana tabacum L. var. Maryland Mammoth) were frozen with a RMC MF7200 propane jet freezer and freeze substituted sequentially with tannic acid and osmium tetroxide/uranyl acetate in acetone. High quality preservation was consistently obtained for epidermal and phloem cells of the leaf, and epidermal, cortical, meristematic, and cap cells of the root tip. Leaf mesophyll cells were also often well frozen. Organelles, including nuclei, endoplasmic reticulum, mitochondria, Golgi bodies, and plastids, showed excellent structural integrity and contrast. Most notable is the superior preservation of the cytoskeleton. Our results demonstrate that the propane jet freezer can be used routinely for high quality cryofixation of higher plant cells in certain complex tissues. This could have important implications for the use of cryofixation approach in a wide range of research in plant biology.

Cryopreservation↗
PubMed1985

Propane and propylene formation during the microsomal metabolism of iproniazid and isopropylhydrazine.

Both iproniazid and isopropylhydrazine were metabolized to the hydrocarbon products, propane and propylene, with nearly identical Michaelis constants and rates. This reaction appeared to be catalyzed by microsomal cytochrome P-450. Isonicotinic acid, a product of iproniazid hydrolysis by various amidases, was produced in only very small quantities, suggesting that the other amidase product, isopropylhydrazine, may not be an obligatory intermediate in the pathway of hydrocarbon formation from iproniazid. Hydrocarbon formation from iproniazid was more sensitive to inhibition in vitro by bis-p-nitrophenylphosphate (used in vivo as an amidase inhibitor) than was isopropylhydrazine. Iproniazid must be directly metabolized by cytochrome P-450 to yield propane and propylene, presumably via an azo ester intermediate which could give rise to an isopropyl radical, the chemical species presumed to be responsible for the hepatoxicity apparent after administration of large doses of iproniazid in vivo.

Alkenes↗
PubMed1994

Propane 2-nitronate is the major genotoxic form of 2-nitropropane.

The mutagenicity of 2-nitropropane in Salmonella typhimurium (strain TA100) was proportional to the pH (range 6.1-9.1) of the medium used for pre-incubation of the agent and for incubation of the agent with the Salmonella. The mutagenicity correlated with an enhanced rate of tautomerase to propane 2-nitronate at relatively high pH as measured by high performance liquid chromatography. Both the mutagenicity in Salmonella typhimurium (strains TA100 and TA102) and the rate of tautomerisation to the nitronate was lower with 2-deutero-2-nitropropane than with non-deuterated 2-nitropropane. Furthermore, 2-deutero-2-nitropropane was less potent in the induction of unscheduled DNA synthesis in rat hepatocytes over a 4-h period. Propane 2-nitronate therefore appears to be pivotal in the causation of the genetic toxicity of 2-nitropropane. The presence of hepatocytes enhanced nitronate production from 2-nitropropane suggesting a contribution from hepatic enzymes in the tautomerisation reaction.

Animals↗
PubMed1992

Propane 2-nitronate is more rapidly denitrified and is more genotoxic than 2-nitropropane in cultured rat hepatoma cells.

We have investigated the importance of nitronate formation from 2-nitropropane (2-NP) for the oxidative metabolism and the genotoxicity of 2-NP in 2sFou rat hepatoma cells. Treatment of the cells with 2-NP for up to 3 h resulted in the time-dependent appearance of nitrite in the culture medium and in a weak induction of DNA repair synthesis. Both nitrite formation and repair induction were markedly enhanced in cells exposed to the anionic form of 2-NP, propane 2-nitronate. These observations suggest that propane 2-nitronate, rather than 2-NP itself, is oxidized by the liver cells to yield a DNA-damaging product. The results also indicate that the nitro/nitronate equilibration in intact liver cells is slow, suggesting that nitronate formation represents the rate-limiting step in the metabolic activation of 2-NP.

Animals↗
PubMed2004

Three cases of sudden death due to butane or propane gas inhalation: analysis of tissues for gas components.

We report three cases of sudden death due to inhalation of portable cooking stove fuel (case 1), cigarette lighter fuel (case 2), and liquefied petroleum gas (LPG) (case 3). Specimens of blood, urine, stomach contents, brain, heart, lung, liver, kidney, and fat were collected and analyzed for propylene, propane, isobutane, and n-butane by headspace gas chromatography. n-Butane was the major substance among the volatiles found in the tissues of cases 1 and 2, and propane was the major substance in case 3. A combination of the autopsy findings and the gas analysis results revealed that the cause of death was ventricular fibrillation induced by hard muscle exercise after gas inhalation in cases 1 and 2, and that the cause of death in case 3 might be hypoxia. It is possible that the victim in case 3 was under anesthetic toxicity of accumulated isobutane which is a minor component of liquefied petroleum gas.

Adipose Tissue↗
PubMed2002

Butane and propane oxidation by engineered cytochrome P450cam.

The haem monooxygenase cytochrome P450cam has been engineered to oxidise the gaseous alkanes butane and propane to butan-2-ol and propan-2-ol, respectively, by the use of bulky amino acid substitutions to reduce the volume of the substrate pocket and thus improve the enzyme-substrate fit: the F87W/Y96F/T101L/V247L mutant oxidizes butane with a turnover rate of 750 min-1 and 95% yield based on NADH consumed while the wild-type enzyme has an activity of 0.4 min-1 with 4% yield.

Binding Sites↗
PubMed2006

Biological formation of ethane and propane in the deep marine subsurface.

Concentrations and isotopic compositions of ethane and propane in cold, deeply buried sediments from the southeastern Pacific are best explained by microbial production of these gases in situ. Reduction of acetate to ethane provides one feasible mechanism. Propane is enriched in (13)C relative to ethane. The amount is consistent with derivation of the third C from inorganic carbon dissolved in sedimentary pore waters. At typical sedimentary conditions, the reactions yield free energy sufficient for growth. Relationships with competing processes are governed mainly by the abundance of H(2). Production of C(2) and C(3) hydrocarbons in this way provides a sink for acetate and hydrogen but upsets the general belief that hydrocarbons larger than methane derive only from thermal degradation of fossil organic material.

Carbon Isotopes↗
PubMed2002

Lecithin microemulsions in dimethyl ether and propane for the generation of pharmaceutical aerosols containing polar solutes.

Water soluble compounds have been incorporated into solution phase metered dose inhalers (MDIs) utilizing lecithin inverse microemulsions in dimethyl ether (DME) and propane. DME and propane acted as both solvent and propellant. Experiments utilizing model propellants (dimethylethyleneglycol (DMEG) and hexane) were used to investigate microemulsion physicochemical phenomena, and the results were used to design and interpret the technically more challenging MDI experiments. NMR and viscosity experiments with model propellants were consistent with a "sphere-to-string" micellar shape change as the solvent was varied from pure DMEG to pure hexane. Water soluble solutes, including selected peptides and fluorescently labeled poly-alpha, beta-[N-(2-hydroxyethyl) D,L-aspartamide] (fPHEAs), dissolved in DME/propane dependent on lecithin and water content. MDIs containing microemulsions generated aerosols with mass median aerodynamic values ranging from 2.7 to 3.1 microns, within the range of commercially available formulations. Fine particle fraction values (50-70%) exceeded those of commercial formulations. fPHEA up to 18 kDa did not adversely affect the aerosol characteristics. Deposition of the aerosol onto a water surface resulted in the formation of liposomes with partially entrapped solute.

Aerosol Propellants↗
PubMed2002

The forensic investigation of propane gas asphyxiation.

Two unusual suicides of a 19-year-old white man and a 47-year-old white man, involving propane inhalation and plastic bag suffocation, are described. The special characteristics of propane gas as an asphyxiant agent are discussed, as well as its effect on the human body. The discussion emphasizes the postmortem examination and the collection of samples for toxicologic analysis.

Adult↗
PubMedDate not supplied

Propane gas dangers and strategies for prevention of injuries.

Although the overall incidence of thermal injuries continues to decrease, the incidence of certain types of burns is alarmingly high. Approximately 3000 propane fires and explosions are reported yearly. More than 9% of these cases result in bodily injury, and the mortality rate is more than 7% of the injured. Most of the accidents are felt to be the result of a lack of knowledge among the general public in regard to the use of liquid petroleum (LP) gas, which is a low-cost and widely used fuel source. A series of accidents that resulted in several injuries in the midsouth area heightened our awareness of the problems associated with LP-gas storage, transportation, and use. A review of the incidence of use and injury, warning systems, product liability status, and prevention strategies are reported to help educate health care providers and increase public awareness of the problems associated with propane gas.

Accident Prevention↗
PubMed2005

Autoerotic accident by inhalation of propane-butane gas mixture.

We present a case of an accidental autoerotic death involving the inhalation of a propane-butane gas mixture, also known as LPG (liquefied petroleum gas). A 19-year-old male was found dead in supine position in his bed in a residential accommodation one day after he was last seen alive. On a personal computer at the end of the bed, a pornographic movie was still running. On his left shoulder, an empty rubber balloon and on the bedside 2 empty "Kisag-Gas" cartridges were found. Toxicologic investigations revealed an intoxication with propane and butane, together with a recent consumption of cannabis. This case report compares the toxicologic findings with other recently published cases, and the theories of the toxic effects are discussed.

Accidents↗
PubMed1987

Safety considerations regarding the use of propane and other liquefied gases as coolants for rapid freezing purposes.

Liquid propane and similar coolants are used in the rapid freezing of biological specimens. These coolants form explosive gas mixtures with air, with a 14,000-fold increase in volume over that of the liquid. The liquefied gases have high vapour pressures and, unless they are maintained below their flashpoint, the vapour above them will reach ignitable concentrations. The flashpoint of liquid propane is -104 degrees C. Ethane has a higher vapour pressure, and vapour mixed with air above liquid ethane can be ignited at a coolant temperature of -130 degrees C. The danger is minimized if the coolant is maintained near its freezing point and under a nitrogen atmosphere, in a fume cupboard. Liquid nitrogen evaporates to a 690-fold increase in volume at room temperature. It is important to ventilate the working area, especially when cryo-sectioning in a small room, otherwise there is a possibility of asphyxiation.

Equipment Safety↗
PubMed1983

Thermostable NAD-linked secondary alcohol dehydrogenase from propane-grown Pseudomonas fluorescens NRRL B-1244.

NAD-linked alcohol dehydrogenase activity was detected in cell-free crude extracts from various propane-grown bacteria. Two NAD-linked alcohol dehydrogenases, one which preferred primary alcohols (alcohol dehydrogenase I) and another which preferred secondary alcohols (alcohol dehydrogenase II), were found in propane-grown Pseudomonas fluorescens NRRL B-1244 and were separated from each other by DEAE-cellulose column chromatography. The properties of alcohol dehydrogenase I resembled those of well-known primary alcohol dehydrogenases. Alcohol dehydrogenase II was purified 46-fold; it was homogeneous as judged by acrylamide gel electrophoresis. The molecular weight of this secondary alcohol dehydrogenase is 144,500; it consisted of four subunits per molecule of enzyme protein. It oxidized secondary alcohols, notably, 2-propanol, 2-butanol, and 2-pentanol. Primary alcohols and diols were also oxidized, but at a lower rate. Alcohols with more than six carbon atoms were not oxidized. The pH and temperature optima for secondary alcohol dehydrogenase activity were 8 to 9 and 60 to 70 degrees C, respectively. The activation energy calculated from an Arrhenius plot was 8.2 kcal (ca. 34 kJ). The Km values at 25 degrees C, pH 7.0, were 8.2 X 10(-6) M for NAD and 8.5 X 10(-5) M for 2-propanol. The secondary alcohol dehydrogenase activity was inhibited by strong thiol reagents and strong metal-chelating agents such as 4-hydroxymercuribenzoate, 5,5'-dithiobis(2-nitrobenzoic acid), 5-nitro-8-hydroxyquinoline, and 1,10-phenanthroline. The enzyme oxidized the stereoisomers of 2-butanol at an equal rate. Alcohol dehydrogenase II had good thermal stability and the ability to catalyze reactions at high temperature (85 degrees C). It appears to have properties distinct from those of previously described primary and secondary alcohol dehydrogenases.

Alcohol Dehydrogenase↗
PubMed1989

Survey of microbial oxygenases: trichloroethylene degradation by propane-oxidizing bacteria.

Microorganisms that biosynthesize broad-specificity oxygenases to initiate metabolism of linear and branched-chain alkanes, nitroalkanes, cyclic ketones, alkenoic acids, and chromenes were surveyed for the ability to biodegrade trichloroethylene (TCE). The results indicated that TCE oxidation is not a common property of broad-specificity microbial oxygenases. Bacteria that contained nitropropane dioxygenase, cyclohexanone monooxygenase, cytochrome P-450 monooxygenases, 4-methoxybenzoate monooxygenase, and hexane monooxygenase did not degrade TCE. However, one new unique class of microorganisms removed TCE from incubation mixtures. Five Mycobacterium strains that were grown on propane as the sole source of carbon and energy degraded TCE. Mycobacterium vaccae JOB5 degraded TCE more rapidly and to a greater extent than the four other propane-oxidizing bacteria. At a starting concentration of 20 microM, it removed up to 99% of the TCE in 24 h. M. vaccae JOB5 also biodegraded 1,1-dichloroethylene, trans-1,2-dichloroethylene, cis-1,2-dichloroethylene, and vinyl chloride.

Bacteria↗