Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Styrenes”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed1987

A personal sampling method for the determination of styrene exposure.

A diffusive sampler, which is suitable for the determination of time-weighted average personal and static exposures to styrene, is described. The sampler is based on a commercially available tube design that is amenable to fully-automated thermal desorption. The performance of the sampler has been evaluated using a protocol, developed by the U.K. Health and Safety Executive, involving both laboratory and field experiments. The sampler has been shown to give results that are similar both in magnitude and precision to those obtained using conventional sorbent tube and pump methods. The diffusive method is preferred because of its simplicity and convenience.

Adsorption↗
PubMed1992

Exposure to styrene and health complaints in the Dutch glass-reinforced plastics industry.

A study of the health hazards for workers exposed to styrene in the Dutch glass-reinforced plastics industry was undertaken. The open mould techniques of filament winding, spraying and hand laminating were chosen for study because exposure of workers using them was expected to be high. Occupational hygiene surveys were conducted in four plants. In addition to measurements of exposure, data on health complaints were collected. In 12 smaller plants exposure was estimated in walk-through surveys. The results show that although most of the plants had implemented control measures such as ventilation and extraction, the levels of exposure constituted a health risk. Time-weighted average concentrations for workers involved in filament winding ranged from 134 to 716 mg m-3, for those who were spraying from 48 to 602 mg m-3 and for those laminating manually from 18 to 538 mg m-3. The 'no-adverse-effect level' based on effects observed in man is considered to be 105 mg m-3, and the acute subjective health effects experienced by the population studied supported this value. To reduce exposure to below 105 mg m-3, control measures should combine engineering with codes of practice adapted to the particular process or processes employed.

Environmental Monitoring↗
PubMed1985

Gassings due to methylene chloride, xylene, toluene, and styrene reported to Her Majesty's Factory Inspectorate 1961-80.

For the period 1961-80, 118 cases of industrial gassings caused by the solvents methylene chloride, xylene, toluene, and styrene were reported to Her Majesty's Factory Inspectorate. The data have been collated and analysed according to the predetermined criteria of age, sex, mode and circumstances of use, clinical effect, and outcome. The means of collection of the data and their objectivity is discussed. The study shows the narcotic effect of these solvents and underlines the dangers of their use in confined spaces. Symptoms were most commonly attributable to the nervous and respiratory systems. The problem of addiction and the vulnerability of the younger worker is also discussed.

Adolescent↗
PubMed1994

Formation of chloroamines from styrene under conditions mimicking those of water "chlorination" treatment.

The reaction of styrene with sodium hypochlorite in the presence of ammonium ion in 0.3 M phosphate buffer (pH 6.0) at room temperature afforded N-chloro-1-phenyl-2-chloroethylamine and N,N-dichloro-1-phenyl-2-chloroethylamine. 1-Phenyl-2-chloroethylamine hydrochloride, obtained as the reduction product of the two N-chloroamines, was shown to be mutagenic in the Salmonella typhimurium test.

Animals↗
PubMed1993

Neuropsychological effects of styrene exposure: a review of current literature.

Research on the neuropsychological effects of exposure to styrene are reviewed, including subjective complaints, laboratory exposure, short- and long-term occupational exposure, possible long-term occupational illness, neuropsychiatric implications, and animals' behavior. The findings are discussed in relation to optimal levels of exposure, drivers' safety, a sensitive neuropsychological screening battery, current controversies, and future directions for research.

Animals↗
PubMed1991

Use of an acrylonitrile-butadiene-styrene (ABS) plastic ring as a matrix in the recovery of bite mark evidence.

Valuable forensic information can be obtained from analysis of human bite mark injuries after careful retrieval of such evidence from living or deceased victims. It is difficult, however, to maintain the anatomical configuration of the skin, especially where body contours complicate the recovery process. Transillumination of the injury pattern in the skin after removal and preservation of the tissue from a deceased victim can provide significant information in the investigation process. A dimensionally stable matrix is required to support the skin's anatomical configuration during and after its removal. The authors have developed a unique and convenient method of heating and contouring a ring of acrylonitrile-butadiene-styrene (ABS) plastic using table salt over a heat source. When this ring is applied to the deceased victim's skin, and a backing material is added for support, removal of the skin and the bite mark can be accomplished more predictably while maintaining the anatomical contour. It is important to record bite marks accurately as soon after discovery as possible; the authors believe that this technique will significantly aid recovery of such evidence either at the crime scene or in the laboratory. A method of inscribing appropriate anatomical markers and case numbers on the rings is also described.

Acrylonitrile↗
PubMed1989

[A thin-layer chromatography method for determining the styrene metabolites mandelic and phenylglyoxylic acid in urine].

A thin-layer chromatographic method is described for the determination of mandelic and phenyglyoxillic acid on silicagel (Silufol UV 254) after extraction from urine of styrene exposed workers. The quantitative determination was performed after eluting the spots. Phenylglyoxilic acid was measured at 255 nm and mandelic acid by derivative spectroscopically estimation of the .CH(OH).COOH -chromophore at 217 nm or by a three-wavelength mode, respectively. The recovery in urine was 80-104% for phenylglyoxilic acid and 99-105% for mandelic acid.

Chromatography, Thin Layer↗
PubMed1994

Styrene induced pancreatic changes in rodents.

Subchronic oral exposure to styrene in rodents (25 or 50 mg/kg/day in mice; 160 or 320 mg/kg/day in rats and guinea pigs, 5 days/week) for 4 weeks resulted in moderate congestion of pancreatic lobules, focal inflammatory reactions around islets (in mice) and altered serum insulin level while blood glucose levels remained unaffected. Increased beta cell degranulation together with characteristic neoformation of islets were predominantly seen in pancreas of guinea pigs.

Animals↗
PubMed1993

Cancer epidemiology among styrene-butadiene rubber workers.

The standardized mortality ratios for some cancers of the lymphohaematopoietic system were high in an early cohort analysis. Since the presence of large numbers of unexposed workers could conceal risks within a cohort, a case-control study was designed to examine the relationship between estimated exposures and the occurrence of these cancers. The results suggested that the risk for leukaemia was associated with exposure to butadiene and with work in specific areas. Modelling, using rank scores, indicated an increase in the risk for leukaemia with increasing exposure score. Use of cases validated by review of hospital records and selection of a new set of controls did not change the findings. The data indicated that comparison of scores within the same time frame improved the model and increased the estimated odds ratio, suggesting that exposure time or dose rate may prove to be the important variable for risk. Exact measurements from the companies involved showed significant correlations between assigned ranks and level of exposure derived from personal monitoring for butadiene but not for styrene. Thus, use of the measured values might be expected to show an association between leukaemia and exposure to butadiene. The standardized mortality ratio for leukaemia among long-term workers hired before 1960 who had worked in the three plants where the geometric mean butadiene level was three to five times higher than those in the other plants is 1.8 times higher than that of the US population. An appropriate algorithm for comparing cases and controls on the bases of the measured samples is being developed.

Butadienes↗
PubMed1993

Scanning electron microscopy of styrene-methylethylketone casts of the airway and the arterial system of the lung.

The method of making casts of airways and the pulmonary arterial system using a styrene polymer resin is described. A human and a dog were used as models. The viscosity of this resin ranges between 40 and 60 dPa/s at 24 degrees C. The elastic rubber tube used for resin injection allows a constant perfusion pressure, i.e., 44 mm Hg and 110 mm Hg for airway and vascular filling, respectively. The casts obtained using this method are suitable both for macro- and microscopic analysis. Shrinkage during polymerization is minimal. Moreover, a preceding lavage is not necessary. Scanning electron microscopy (SEM) of cast lungs showed the endothelial cell nuclei imprints on vessels. Computer assisted analysis of alveolar capillary interspaces showed that these holes are larger than those described in normal rats. The diameter of alveolar capillaries in dogs is almost the same as in the normal rat lung. When casting the airways, alveolar cells and/or materials inhaled might be preserved and observed in SEM.

Animals↗
PubMed2001

Cumulative exposure to styrene and visual functions.

BACKGROUND: Results from a 1990-1992 longitudinal study of several reinforced plastics plants showed that for those workers whose styrene exposure had decreased, color vision (CV) improved; while near visual contrast sensitivity (CS) was poorer. METHODS: In 1999, we retested these visual functions in 18 workers with good visual acuity. A cumulative exposure index (CEI), corrected for respirator use, was calculated for each worker. RESULTS: Intra-individual comparison of mandelic acid (MA) showed a significant decrease over time (Friedman; P = 0.015), but current values were not related to CEI. For CV, no significant difference was observed between 1992 and 1999; present results were not related to MA or CEI. The CS profile decreased over time, with significant differences at 3 cpd (Friedman; P < 0.05). CS did not vary with MA levels, but was significantly depressed at the intermediate frequencies among those in the upper CEIH category (Kruskal-Wallis; P < 0.05). CONCLUSIONS: These findings suggest that CS loss increases with long-term cumulative exposure, reflecting chronic damage to the neuro-optic pathways.

Adult↗
PubMed2005

Multistate reactivity in styrene epoxidation by compound I of cytochrome p450: mechanisms of products and side products formation.

Density functional theoretical calculations are used to elucidate the epoxidation mechanism of styrene with a cytochrome P450 model Compound I, and the formation of side products. The reaction features multistate reactivity (MSR) with different spin states (doublet and quartet) and different electromeric situations having carbon radicals and cations, as well as iron(III) and iron(IV) oxidation states. The mechanisms involve state-specific product formation, as follows: a) The low-spin pathways lead to epoxide formation in effectively concerted mechanisms. b) The high-spin pathways have finite barriers for ring-closure and may have a sufficiently long lifetime to undergo rearrangement and lead to side products. c) The high-spin radical intermediate, (4)2(rad)-IV, has a ring closure barrier as small as the C--C rotation barrier. This intermediate will therefore lose stereochemistry and lead to a mixture of cis and trans epoxides. The barriers for the production of aldehyde and suicidal complexes are too high for this intermediate. d) The high-spin radical intermediate, (4)2(rad)-III, has a substantial ring closure barrier and may survive long enough time to lead to suicidal, phenacetaldehyde and 2-hydroxostyrene side products. e) The phenacetaldehyde and 2-hydroxostyrene products both originate from crossover from the (4)2(rad)-III radical intermediate to the cationic state, (4)2(cat,z(2) ). The process involves an N-protonated porphyrin intermediate that re-shuttles the proton back to the substrate to form either phenacetaldehyde or 2-hydroxostyrene products. This resembles the internally mediated NIH-shift observed during benzene hydroxylation.

Cytochrome P-450 Enzyme System↗
PubMed1982

Hepatic effects of orally administered styrene in rats.

Adult male rats receiving styrene by gavage (200 or 400 mg kg-1, 6 days a week) for 100 days exhibited a significant dose-dependent increase in hepatic benzo[a]pyrene hydroxylase and aminopyrine-N-demethylase, a decrease in glutathione-S-transferase and no change in glucose-6-phosphatase. A decrease in the activity of mitochondrial succinic dehydrogenase and beta-glucuronidase was also observed. Activity of acid phosphatase was decreased only at the higher dose level. Levels of serum glutamic oxaloacetic transaminase and glutamic pyruvic transaminase were elevated only at the higher dose level. The absolute and relative weights of the liver of control and treated animals showed no significant difference. Histopathological studies of the liver tissue revealed tiny areas of focal necrosis, consisting of few degenerated hepatocytes and inflammatory cells at the higher dose level only.

Administration, Oral↗
PubMed1975

Potential fibrinolytic agents: versatile synthetic route to novel 4-(branched alkyl)benzoic acids via beta-monosubstituted or beta,beta-disubstituted styrene-4-carboxylic acids.

A versatile and unambiguous synthetic route to some novel 4-(branched alkyl)benzoic acids via their beta-monosubstituted or beta,beta-disubstituted styrene-4-carboxylic acid precursors is described. The procedure starts with readily available aldehydes or ketones and the common intermediate p-bromobenzyltriphenyl-phosphonium bromide in a Wittig reaction and proceeds in good yield through p-bromostyrene and p-cyanostyrene intermediates. Several benzoic acid derivatives were of potential biological interest as fibrinolytic agents.

Benzoates↗
PubMed2004

Synthesis and characterization of polymeric linseed oil grafted methyl methacrylate or styrene.

Syntheses of wholly natural polymeric linseed oil (PLO) containing peroxide groups have been reported. Peroxidation, epoxidation and/or perepoxidation reactions of linseed oil, either under air or under oxygen flow at room temperature, resulted in polymeric peroxides, PLO-air and PLO-ofl, containing 1.3 and 3.5 wt.-% of peroxide, with molecular weights of 2 100 and 3 780 Da, respectively. PLO-air contained cross-linked film up to 46.1 wt.-% after a reaction time of 60 d, associated with a waxy, soluble part (PLO-air-s) that was isolated with chloroform extraction. PLO-ofl was obtained as a waxy, viscous liquid without any cross-linked part at the end of 24 d under visible irradiation and oxygen flow. Polymeric peroxides, PLO-air-s and PLO-ofl initiated the free radical polymerization of both methyl methacrylate (MMA) and styrene (S) to give PMMA-graft-PLO and PS-graft-PLO graft copolymers in high yields with Mw varying from 37 to 470 kDa. The polymers obtained were characterized by FT-IR, (1)H NMR, TGA, DSC and GPC techniques. Cross-linked polymers were also studied by means of swelling measurements. PMMA-graft-PLO graft copolymer film samples were also used in cell-culture studies. Fibroblast cells were well adhered and proliferated on the copolymer film surfaces, which is important in tissue engineering.

Animals↗
PubMed2004

Simultaneous determination of the urinary metabolites of benzene, toluene, xylene and styrene using high-performance liquid chromatography/hybrid quadrupole time-of-flight mass spectrometry.

A simple and rapid method using reversed-phase liquid chromatography/tandem mass spectrometry (LC/MS/MS) for the simultaneous determination of the urinary metabolites of benzene, toluene, xylene and styrene in human urine specimens and standard solutions is described. A hybrid quadrupole/time-of-flight (QqTOF) mass spectrometer was compared for the determination of metabolite of aromatic solvents in urine samples. The metabolites selected were: trans,trans-muconic acid, hippuric acid, o-, m- and p-methylhippuric acid and phenylglyoxylic acid. The compounds were well separated from each other on narrow-bore 1-mm i.d. reversed-phase LC C-18 columns. Average recoveries for loading 100 microL of urine samples varied from 88-110% and the quantification limits were less than 30 ng/mL for each analyte (3 ng/mL for trans,trans-muconic acid). The qualitative information obtained (mass accuracy, resolution and full-scan spectra) with the QqTOF mass spectrometer allows a secure identification of analytes in biological matrices.

Benzene↗
PubMed1982

Styrene and methyl methacrylate in the industrial environment as a risk factor of chronic obstructive lung disease.

The main objective was to assess the biological effect of styrene and methyl methacrylate on the respiratory system in the industrial population. A total of 454 males from the exposed group and 683 workers from the control group were examined. The health status of the workers was evaluated by standardized interviews on chest symptoms and lung function testing. The environmental measurements were performed in all work places where the persons under study were employed. There was practically no differences in the prevalence of chronic chest symptoms in both groups of workers but the frequency of lung obstruction appeared to be more than twice as high among the exposed persons in comparison with the controls. A large proportion of cases with lung obstruction did not show any chronic chest symptoms. It appeared from the study that the environmental factor developed a much more harmful effect on lung function than smoking, and one effect was independent of the other.

Adult↗