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PubMedDate not supplied

Role of chemical mediators in bronchoconstriction induced by kerosene.

Kerosene is a by product of petroleum used in some countries for cleaning, lighting and cooking purposes. Rodriguez de la Vega et al (1981) have presented evidences of the relation between bronchial asthma and the manipulation of kerosene. Since the experiments performed by our group showed that the acute inhalation of the aerosol of kerosene induces bronchoconstriction in rabbits (Casacó et al 1982), we investigated its effect on guinea pig respiratory physiology. In order to elucidate the implication of histamine and arachidonic acid metabolites in kerosene induced bronchoconstriction, we investigated the influence of the administration to guinea pig of a single dose of the histamine H1 antagonist mepyramine (0.1 mg/kg i.v.) 10 minutes before the aerosol and also the effect of the steroidal antinflammatory drug triamcinolone in rabbits (5 mg/kg i.m.) daily during 4 days before the inhalation of kerosene. The histamine concentrations in guinea pig blood before and after the aerosol were also compared. The inhalation of kerosene during 5 min. (20.4 mg/L) by guinea pigs resulted in an increase of airway resistance without increase of blood histamine concentration. On the other hand, the bronchoconstrictive effect of kerosene in guinea pigs and rabbits was not modified by the previous treatment with mepyramine or triamcinolone respectively. The results suggest that the acute bronchoconstriction induced by kerosene is mediated neither by stimulation of histamine H1 receptors nor by the release of chemical mediators.

Airway Resistance↗
PubMed1983

Vanadium: chemistry and the kidney.

Vanadium (V), a metallic element of the first transition series, is widely distributed in the environment. Although an essential trace element in higher animals, chronic exposure to V is of concern because of its increased concentration near industrial operations, its occurrence in the ash of combustion products of petroleum and coal, and its subsequent biomagnification in the environment. V is found in trace amounts in both terrestrial and aquatic animals and in solution can form inorganic orthovanadate oxyanions that, if absorbed, are eliminated primarily by the kidneys. Because V is often found concentrated in renal tissue to the largest extent in the body, the kidneys may represent a major site of action. Moreover, V in the vanadate configuration increases the urinary excretion of solutes and water in the rat, and inhibits renal organic ion accumulation and renal Na+, K+-ATPase in vitro and in vivo. Furthermore, as a nutritionally required element, V may play a regulatory role in salt and water excretion by modification of the Na+ pump in the kidney.

Animals↗
PubMed1982

Extraction procedures for oilseeds and related high fat-low moisture products.

A combined sample preparation/extraction procedure is presented for pesticide residue analysis of oilseeds and related high fat-low moisture products. The procedure utilizes high-speed milling to prepare the sample and high-speed homogenization in the extraction step to achieve what is apparently quantitative isolation of both incurred residues and natural oils. A separate, simple, oil determination step allows findings to be reported on either the fat or whole product basis. Petroleum ether, ethyl ether-petroleum ether (1 + 1), and ethanol are used serially as the extractants. Usual fatty food cleanup procedures and multiresidue gas chromatographic detection techniques are utilized. The procedure presented in this paper is a refinement of earlier work which used a homogenizer both to grind and to extract samples of unground seeds and which demonstrated essentially complete extraction of endrin residues in soybeans and DDT residues in mustard seed. Identical samples analyzed by the currently recommended shakeout procedure, 29.012, gave recoveries of approximately 50% of the total residues. The procedure presented in this paper was satisfactorily tested on 13 different oilseed types and one sample of soda crackers. Oil content for these samples ranged from 5 to 69%.

Arachis↗
PubMed1993

Preparation of 2-alkoxy-4-alkyl-5(4H)-oxazolones from mixed anhydrides of N-alkoxycarbonylamino acids.

A general procedure for the preparation of 2-alkoxy-4-alkyl-5(4H)-oxazolones (AlkOx's) from N-tert-butoxy-, N-benzyloxy- and N-(9-fluorenylmethoxy)-carbonylamino acids has been devised. Purified mixed anhydrides are prepared from the parent acid and isopropenyl chloroformate and left in chloroform (Boc) for 24 h or dimethylformamide (Z, Fmoc) for 0.5-2 h. Symmetrical anhydride that may originate from disproportionation or reaction of AlkOx with hydrolyzed product is partially removed by extracting the AlkOx into petroleum ether. The products contain 0.5-30% of symmetrical anhydride.

Amino Acids↗
PubMedDate not supplied

[Mathematical simulation of accumulation of opportunistic micromycetes in petroleum-polluted soils].

The impact of pollution of different types of soils (leached chernozem, grey wood and dark-grey wood soils) with petroleum and its products on the size, species-specific composition, and accumulation of opportunistic micromycetes was studied in long-term field microallotment and laboratory conditions. Petroleum and its refining products were shown to increase the size of micromycetes and to change their structure and species diversity. A mathematical model has been developed, which describes the time course of changes in the size of mushroom propagules under different environmental conditions.

Fungi↗
PubMed1987

Dehydrodolichyl diphosphate synthetase from rat seminiferous tubules.

Homogenates of seminiferous tubules from rat testes catalyzed the incorporation of label from [14C]isopentenyl diphosphate into a variety of polyprenyl products. Long chain polyprenyl mono- and diphosphates were formed as major products when undesirable side reactions were minimized. The long chain polyprenyl diphosphate synthetase was measured as a sum of the mono- and diphosphate derivatives formed and was dependent on the addition of t,t-farnesyl diphosphate, isopentenyl diphosphate, and divalent cation. The highest activity was associated with the membranous fractions, whereas activity was negligible in the cytosolic fraction. The products of this prenyl transferase were labile to acid and yielded petroleum ether soluble products which indicated that the alpha-isoprene unit was unsaturated. Hydrolysis of either the polyprenyl mono-or diphosphates with a testicular phosphatase in the absence of NaF yielded C75, C80, C85, and C90 polyprenols. The chain lengths of the products of the synthetase suggest that this enzyme is responsible for the de novo biosynthesis of dehydrodolichyl diphosphates which are precursors of the dolichyl derivatives found in testes.

Alkyl and Aryl Transferases↗
PubMed1979

Lung cancer in Louisiana: death certificate analysis.

In a search for etiologic clues, a review was made of death certificates of residents in a cluster of Louisiana parishes, mainly in the southern part of the state, where lung cancer mortality was high. A comparison of the statements on occupation for 3,327 patients with lung cancer and those of 3,327 controls (matched by sex, race, age, and parish of residence) during 1960-75 revealed an approximately twofold excess risk associated with transportation equipment manufacture, mainly shipbuilding, and the fishing industry. Smaller elevations of lung cancer risk were found among older men who had been employed in petroleum exploration and production and among male and female residents of towns where the petroleum industry was a major employer. In addition, Acadian ancestry was associated with a higher risk of lung cancer among older male and female residents.

Death Certificates↗
PubMed1999

Poly(beta-hydroxybutyrate) production in oilseed leukoplasts of brassica napus

Polyhydroxyalkanoates (PHAs) comprise a class of biodegradable polymers which offer an environmentally sustainable alternative to petroleum-based plastics. Production of PHAs in plants is attractive since current fermentation technology is prohibitively expensive. The PHA homopolymer poly(beta-hydroxybutyrate) (PHB) has previously been produced in leaves of Arabidopsis thaliana (Nawrath et al., 1994, Proc Natl Acad Sci USA 91: 12760-12764). However, Brassica napus oilseed may provide a better system for PHB production because acetyl-CoA, the substrate required in the first step of PHB biosynthesis, is prevalent during fatty acid biosynthesis. Three enzymatic activities are needed to synthesize PHB: a beta-ketothiolase, an acetoacetyl-CoA reductase and a PHB synthase. Genes from the bacterium Ralstonia eutropha encoding these enzymes were independently engineered behind the seed-specific Lesquerella fendleri oleate 12-hydroxylase promoter in a modular fashion. The gene cassettes were sequentially transferred into a single, multi-gene vector which was used to transform B. napus. Poly(beta-hydroxybutyrate) accumulated in leukoplasts to levels as high as 7.7% fresh seed weight of mature seeds. Electron-microscopy analyses indicated that leukoplasts from these plants were distorted, yet intact, and appeared to expand in response to polymer accumulation.

Journal Article↗
PubMed1996

Leukemia mortality by cell type in petroleum workers with potential exposure to benzene.

Workers in the petroleum industry are potentially exposed to a variety of petrochemicals, including benzene or benzene-containing liquids. Although a large number of studies of petroleum workers have been conducted to examine leukemia and other cancer risks, few existing studies have investigated cell-type-specific leukemias. One of the major reasons for the lack of cell-type-specific analysis was the small number of deaths by cell type in individual studies. In the present investigation, all cohort studies of petroleum workers in the United States and the United Kingdom were combined into a single database for cell-type-specific leukemia analysis. The majority of these workers were petroleum refinery employees, but production, pipeline, and distribution workers in the petroleum industry were also included. The combined cohort consisted of more than 208,000 petroleum workers, who contributed more than 4.6 million person-years of observation. Based on a meta-analysis of the combined data, cell-type-specific leukemia risks were expressed in terms of standardized mortality ratios (meta-SMRs). The meta-SMR for acute myeloid leukemia was 0.96. The lack of an increase of acute myeloid leukemia was attributed to the low levels of benzene exposure in the petroleum industry, particularly in comparison to benzene exposure levels in some previous studies of workers in other industries, who had been found to experience an increased risk of acute myeloid leukemia. Similarly, no increase in chronic myeloid, acute lymphocytic, or chronic lymphocytic leukemias was found in petroleum workers (meta-SMRs of 0.89, 1.16, and 0.84, respectively). Stratified meta-analyses restricted to refinery studies or to studies with at least 15 years of follow-up yielded similar results. The findings of the present investigation are consistent with those from several recent case-control studies of cell-type-specific leukemia. Patterns and levels of benzene exposure in the petroleum industry are reviewed. The results of the present epidemiologic investigation are discussed in conjunction with recent advances in leukemogenesis from other scientific disciplines.

Benzene↗
PubMed2006

[Co-expression of Rhodococcus sp. DS-3 dszABC and dszD gene with incompatible plasmids in Escherichia coli].

Biological dusulfurizaion of petroleum feedstocks and products may offer an attractive alternative to reduce sulfur oxide emissions that cause serious environmental pollution. Dibenzothiophene (DBT), a model of organic sulfur compound in petroleum, can be microbially desulfurized without degradation of the organic structure by 4S pathway. Three desulfurization enzymes (DszA, DszB and DszC) and flavin reductase (DszD) are involved in sulfur-specific DBT desulfurization. DszA and DszC are FMNH2-dependent monoxygenases, FMNH2 is provided from the freely diffusible FMNH2 pool in the cell, and is replenished by DszD. So, co-expression of the desulfurization enzymes and flavin reductase can enhance the rate of sulfur removal. In the present work two incompatible plasmids: pBADD and paN2 were constructed. The paN2 allows Escherichia coli to liberate the sulfur of DBT and DBTs and pBADD produces a flavin reductase. They were co-expressed in Escherichia coli B121 (DE3). The soluble products of DszA, DszB, DszC and DszD accounted for 7.6%, 3.5%, 3.1% and 18% of the total proteins in co-expressed system. The desulfurization rate of lysate of E. coli BL21- pBADD + paN2 is 12.03 micromol/(h x mg) Dsz protein and about 5.4-fold of that of E. coli BL2-paN2. Experiment were also conducted using resting cell with the 0.6 wt% DBT in n-hexadecane as model diesel oil. After 24 hours reaction, 0.42 mmol/L (about 84%) DBT was converted to 2-HBP by E. coli BL21- pBADD + paN2, however, there was only 0.08 mmol/L (about 16%) DBT was desulfurized by E. coli BL2-paN2. The maximum desulfurization rate of E.coli BL21-pBADD + paN2 is about 67 micromol/h. The result shows that DszD enhances the rate of 2-HBP production when co-expressed in vivo with the desulfurization enzymes.

Bacterial Proteins↗
PubMed1990

An evaluation of the epidermal carcinogenic potential of cutting fluids.

Epidermal cancer in humans has been associated with industrial exposure to products derived from unrefined petroleum distillates. Because of this association many of these products, including cutting fluids, are now normally produced from highly refined lubricant base oils. Since highly refined oils are not dermally carcinogenic, one would predict that formulated products prepared from these oils would similarly be non-tumorigenic. However, there are experimental data that suggest that fresh cutting fluids might be dermally carcinogenic and that industrial usage might increase the carcinogenic hazard. The current studies evaluated solvent-extracted lubricant base oils and several products, including fresh and used cutting fluids and certain related industrial oils. These materials were all tested for tumorigenic potential in mouse epidermal carcinogenesis bioassays. None of the solvent-extracted lubricant base oils were dermal carcinogens. Similarly, the cutting fluids and industrial oils formulated from these base oils were not dermally carcinogenic. Finally, there was no evidence that industrial usage influenced the carcinogenic potential of these oils. It was concluded that solvent-extracted oils and the products derived from these oils pose minimal skin cancer hazards when used under appropriate conditions in industrial settings.

Animals↗