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At least 703 records · Page 39Linked to original sources
PubMed2002

Isolation and identification of some unknown substances in disposable nitrile-butadiene rubber gloves used for food handling.

In Japan, disposable gloves made from nitrile-butadiene rubber (NBR) are frequently used in contact with foods. In a previous paper, we investigated substances migrating from various gloves made of polyvinyl chloride, polyethylene, natural rubber and NBR. Zinc di-n-butyldithiocarbamate (ZDBC), diethyldithiocarbamate (ZDEC) used as vulcanization accelerators, di(2-ethylhexyl)phthalate (DEHP) used as a plasticizer and many unknown compounds that migrated from NBR gloves into n-heptane were detected by GC/MS. In this paper, six unknown compounds were obtained from one kind of NBR glove by n-hexane extraction and each was isolated by silica gel chromatography. From the results of NMR and mass spectral analysis of the six unknown compounds, their structures are proposed as 1,4-dione-2,5-bis(1,1-dimethylpropyl)cyclohexadiene (1), 2-(1,1-dimethylethyl)-4-(1,1,3,3-tetra methylbutyl)phenol (2), 2,6-bis(1,1-dimethylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol (3), 2,4-bis(1,1,3,3-tetramethylbutyl)phenol (4), 2-(1,1-dimethylethyl)4,6-bis(1,1,3,3-tetramethylbutyl)phenol (5) and 2,4,6-tris(1,1,3,3-tetramethylbutyl)phenol (6). Compound 1 was observed in five of the seven kinds of NBR gloves, and compounds 2-4 and 6, which are not listed in Chemical Abstract (CA), were present in four kinds of gloves.

Disposable Equipment↗
PubMed1998

Combined GC and sniffing port analysis of volatile compounds in rubber rings mounted on beer bottles.

For product development reasons two types (A and B) of rubber rings, used on clasps of swing top beer bottles, were investigated for the presence of volatile compounds, which could affect the taste/odour of the packed beer due to (vapour phase) migration. Samples were incubated under different conditions and, after dynamic headspace sampling, analysed by combined GC and sniffing port analysis. Compounds were also identified by GC-MS. The main differences were located in the presence of isobutene isomers in Ring Type A, which were absent in Ring Type B. These compounds were described mainly as 'toy-like' and 'rubber'. Therefore the risk for off-flavour development is expected to be diminished by using Ring Type B.

Beer↗
PubMed1998

Adaptive Process Control in Rubber Industry.

This paper describes the problems and an adaptive solution for process control in rubber industry. We show that the human and economical benefits of an adaptive solution for the approximation of process parameters are very attractive. The modeling of the industrial problem is done by the means of artificial neural networks. For the example of the extrusion of a rubber profile in tire production our method shows good resuits even using only a few training samples.

extruder mask estimation↗
PubMed1982

A hematology survey of workers at a styrene-butadiene synthetic rubber manufacturing plant.

A previous epidemiologic study of the U.S. rubber industry indicated that there has been an excess of leukemia and lymphoma mortality among hourly workers at one styrene-butadiene rubber manufacturing plant. This investigation was a combined industrial hygiene and hematology cross-sectional survey at the same plant. The objectives of the survey were to quantify exposure levels for styrene, butadiene, benzene and toluene, and to relate these levels to hematologic variation. Personal air samples and blood specimens were obtained from 157 production workers. All exposure levels for the four chemicals assayed were well below recommended standards. The higher mean styrene (13.67 ppm) and butadiene (20.03 ppm) concentrations were found in the Tank Farm area; in all other departments the mean levels for the four chemicals were less than 2 ppm. The Tank Farm workers had slightly lower levels of circulating erythrocytes, hemoglobin, platelets and neutrophils, and slightly higher mean corpuscular red cell volumes and neutrophil band counts than the other workers. Overall, in this population there was no pronounced evidence of hematologic abnormality, as determined from examination of peripheral blood.

Adult↗
PubMed1985

Characterization and temperature dependence of PAH emissions from a simulated rubber combustion operation.

The operation investigated uses two induction furnaces for removal of rubber from tracked-vehicle treads. A laboratory-scale simulation of the field operation was employed to generate emissions at 399 degrees C (750 degrees F) and 677 degrees C (1250 degrees F), and emission samples were collected using glass fiber filters and Tenax as the sampling media. Sampling and analytical methods were developed and evaluated with 10 representative polynuclear aromatic hydrocarbons (PAH). High-pressure liquid chromatography (HPLC) and gas chromatography/mass spectrometry (GC/MS) were used to characterize emissions. The PAH were profiled as subsets and graphically displayed as micrograms (micrograms) of emissions per kilogram of rubber and as percentages of total emissions. In each subset, relative amounts of PAH were found to be related to combustion temperatures. Identical coal tar pitch volatiles (CTPV) exposures to emissions generated at the two temperatures studied would result in a 178-fold difference in exposure to carcinogenic PAH.

Air Pollutants, Occupational↗
PubMed2004

Binding and measuring natural rubber latex proteins on glove powder.

Cornstarch used as a donning powder on natural rubber latex (NRL) gloves adsorbs NRL proteins. During glove use, powder-carried proteins can be aerosolized and can cause allergic reactions in NRL sensitized individuals. The amount of NRL proteins bound to glove powder and its relative relationship to the total amount of proteins on the glove has not been studied, due to the difficulty in measuring proteins on powder. Using the ELISA inhibition assay for NRL proteins [Standard test method for the immunological measurement of antigenic protein in natural rubber and its products. In: The Annual Book of ASTM Standards; ASTM: West Conshohocken, PA, 2000; ASTM D 64-0] we have investigated possible protocol modifications in order to include measurement of proteins bound to glove powder, as well as the water-extractable glove proteins. Possible interference of the starch itself was evaluated by adding clean cornstarch to the assay. No significant interference was observed with powder concentrations below 5 mg/mL. We analyzed 19 extracts of powdered surgical and examination gloves before and after removal of the particulate component. Comparison of NRL glove extracts with, and without, the cornstarch powder fraction indicated significant variations in the ratios of powder-bound protein and corresponding water-extractable protein. The ratios did not appear to correlate with either the total protein on the glove, the glove weight, or the total amount of powder on the glove. However, when virgin glove powders were exposed to NRL proteins, binding was proportional to the protein concentration in the suspension. Temperature in the range from 4 degrees C to 37 degrees C, did not affect binding intensity, while a higher pH resulted in a higher level of protein associated with, or bound to, the starch. The major differences in the propensity for NRL protein binding were observed among different glove powders. The data indicate that the amount of protein that binds to glove powder does not depend only on the initial protein levels in the raw NRL. More likely, other physical or chemical factors introduced during the manufacturing process, as well as the properties of the donning powder itself, may influence protein binding. Moreover, we demonstrated that the ELISA inhibition assay could be successfully modified for quantitation of proteins adsorbed on the glove powder, together with water-extractable proteins.

Enzyme-Linked Immunosorbent Assay↗
PubMed2006

Meta-analysis of mortality and cancer incidence among workers in the synthetic rubber-producing industry.

Production of synthetic rubber involves exposure to several potentially harmful chemicals. The authors carried out a systematic review and meta-analysis of cohort studies of workers in the rubber-producing industry. Data were obtained from computerized literature searches of several databases from their inception through December 2003. The reference lists of identified articles were inspected for further relevant articles. The authors conducted random-effects meta-analyses of log standardized mortality ratios (SMRs)/standardized incidence ratios. Heterogeneity between study results was explored through subgroup analyses and meta-regression on cohort demographic factors and study quality indicators. The authors identified 36 published articles reporting information on 31 different cohort groups. The meta-SMR was 0.86 (95% confidence interval (CI): 0.82, 0.91) for all-cause mortality (28 cohorts) and 0.94 (95% CI: 0.89, 1.01) for all malignant neoplasms (27 cohorts). Heterogeneity was observed for these endpoints and for the majority of disease-specific outcomes. Statistically significant excesses were observed for diabetes (meta-SMR=1.36, 95% CI: 1.17, 1.59) (five cohorts) and leukemia (meta-SMR=1.21, 95% CI: 1.03, 1.43) (16 cohorts), the latter particularly for persons working exclusively in nontire manufacturing (meta-SMR=1.70, 95% CI: 1.14, 2.54) (four cohorts). Excesses highlighted in previous narrative reviews were not substantiated. Interpretation of these results is complicated by substantial unexplainable heterogeneity; small excesses in specific mortality outcomes may have been disguised by the healthy worker effect.

Diabetes Mellitus↗
PubMed1999

Permeability of nitrile rubber, latex, polyurethane, and neoprene gloves to 18 antineoplastic drugs.

The permeability of four glove materials to various antineoplastic drugs was studied. Eighteen antineoplastic drugs posing potential health hazards to handlers were prepared at the highest concentrations normally encountered by hospital personnel. Four glove materials-nitrile rubber, latex, polyurethane, and neoprene-were exposed to the drugs for 30, 60, 90, and 120 minutes. Glove thickness was measured with an electronic digital caliper. Random samples of material were selected from the glove fingertips, and triplicate samples were tested for each drug at each interval. For a majority of the drugs, a bacterial mutagenicity assay was used to measure the amount of drug (if any) that permeated the material. High-performance liquid chromatography was used for drugs not tested with the bacterial assay. The nitrile gloves were the thinnest (0.12 mm), and the latex gloves were the thickest (0.18 mm). The four materials were generally impermeable to each drug. One sample of the nitrile gloves appeared to have a defect, allowing >5% of the drug solution to pass through at 30 minutes. One sample each of the latex, polyurethane, and neoprene gloves demonstrated minimal permeability (< or =1%): One latex glove sample was permeated by carmustine, and paclitaxel permeated one sample each of the polyurethane and neoprene materials. Nitrile rubber, latex, polyurethane, and neoprene gloves were impermeable to 18 antineoplastic drugs in most, but not all, cases.

Antineoplastic Agents↗
PubMed1993

Prevention and control of chemical exposures in the rubber manufacturing industry in The Netherlands.

In a survey in the rubber manufacturing industry in The Netherlands both the chemical and physical exposure of operators as well as company policies on working conditions were assessed. Defining the effectiveness of control measures was a part of this study and is the subject of this article. A method of solution-directed workplace analysis was applied to compare and evaluate the control measures within this branch of industry. Elimination of sources appears to be a strategy for prevention which has been adopted on only a limited scale. Control of exposure to particulates is more frequently applied, with local exhaust ventilation as the most important control measure. Both qualitative and quantitative analysis confirmed that local exhaust ventilation has a limited effect. Dust-free forms of chemicals, especially those with health risks, are used on only a moderate scale. In addition to hazard identification and evaluation based on exposure levels, the foreseeable risks associated with the design and requirements of production processes were established. The forthcoming industrial agreement for the rubber manufacturing industry in The Netherlands will, amongst other measures, stimulate use of source related strategies.

Environmental Monitoring↗
PubMed1986

Intracuff and "leak-past" pressures of red rubber, latex and p.v.c. tracheal tubes. A laboratory and clinical study.

Measurements were made in the laboratory of the changes with time of the intracuff pressure, the leak-past pressure (the airway pressure at which gas begins to leak past the cuff) and the cuff volume for 9.5-mm tracheal tubes: red rubber, latex (both Leyland Medical) and p.v.c. (Portex Blue Line). The cuffs were inflated with air and exposed to air or air with enflurane or halothane, usually for 90 min. Measurements of leak-past pressure with these tubes were also made for 75 min in patients whose lungs were ventilated with air and enflurane or air and halothane. The following conclusions can be drawn. Enflurane and halothane had little effect. The intracuff pressure always decreased, but the cuff material crept under the continuous stress, so that cuff volume changed little. The leak-past pressure actually increased over at least 75 min with the p.v.c. tubes, but decreased consistently with the red rubber and latex tubes.

Adult↗
PubMedDate not supplied

HPLC determination of rubber septum contaminants in the iodinated intravenous contrast agent (sodium iothalamate).

A simple and rapid method is described for the determination of 2-mercaptobenzothiazole and mercaptobenzothiazole disulfide leached from rubber closures into the iodinated contrast medium (sodium iothalamate). The contaminants were extracted with methylene chloride and analyzed by high-performance liquid chromatography using ultraviolet detection at wavelengths of 272 and 328 nm. The structures of the impurities were confirmed unequivocally by mass spectrometry. The minimum detectable level was 1 microgram/100 mL (0.01 ppm). The quantitation of contaminants leached from rubber stoppers provides a means for evaluating possible health risks of the extractables.

Benzothiazoles↗
PubMedDate not supplied

Volatile nitrosamine levels in rubber teats and pacifiers available in New Zealand.

Samples of rubber baby bottle teats and pacifiers available in New Zealand were analyzed for nitrosamines by HPLC-TEA. These products, which were manufactured in the USA, Singapore, West Germany, England, and Japan contained one to three nitrosamines. All but one product, which was made of synthetic polyisoprene rubber complied with the US Food and Drug Administration regulatory limit of 60 ng/g. The mean level of total nitrosamines in 11 of the 12 products was 34 ng/g with a range from 9-63 ng/g. The twelfth product recorded a level of 190 ng/g total nitrosamines.

Chromatography, High Pressure Liquid↗
PubMed1997

Cohort mortality study of rubber and plastics product makers in Italy.

A retrospective cohort mortality study was carried out in 20 industrial factories in the Local Health Unit Bologna Sud (Emilia Romagna, Italy), where different rubber and plastics products were manufactured. The cohort consisted of 925 subjects (578 males and 347 females) employed for at least six months continuously; follow-up was between the beginning of operation of each factory, ranging between mid fifties and mid seventies, and 31 December 1989. For those exposed more than one year cause specific Standardized Mortality Ratios (SMRs) were computed using regional rates for comparison, 90% confidence intervals (CI) were calculated assuming the Poisson distribution. Among the 748 subjects employed for more than one year (457 males and 291 females) there were no lost to follow-up, 54 individuals were dead (41 males and 13 females) and for three subjects the cause of death was unknown. The results showed that all causes mortality was above expectancy in the total cohort (SMR = 123; 54 Obs; 90% CI = 97-154), among males (SMR = 117; 41 Obs; 90% CI = 89-152) and females (SMR = 143; 13 Obs; 90% CI = 85-228). Increased mortality for all malignant tumours was observed in the total cohort (SMR = 150; 25 Obs; 90% CI = 104-209) and for both genders. All nine lung cancer cases were observed among males, the SMR was equal to 218 and was statistically significant; seven cases occurred at duration of exposure less than 10 years and six at latency up to 20 years. The interpretation in terms of causality of the present investigation is limited by the small number of observations and by exposure definition solely in terms of employment in the study factories; nonetheless the results are indicating the existence, in this group of rubber and plastics product makers, of an adverse health effect which deserve further investigation.

Adult↗
PubMed2001

Cross-Reactivity studies of gutta-percha, gutta-balata, and natural rubber latex (Hevea brasiliensis).

Gutta-percha and gutta-balata are derived from the Paliquium gutta and Mimusops globsa trees, respectively, that are in the same botanical family as the rubber tree Hevea brasiliensis. For this reason the potential for immunological cross-reactivity between the gutta-percha and gutta-balata used in endodontics and natural rubber latex (NRL) has been the subject of some controversy, because these products may be used in latex-allergic individuals. The objective of this study was to investigate the potential cross-reactivity between gutta-percha, gutta-balata, and NRL. Physiological extracts of seven commercially available gutta-percha products, raw gutta-percha, raw gutta-balata, and synthetic transpolyisoprene were each analyzed for cross-reactivity with NRL in a competitive radioallergosorbent test inhibition assay. No detectable cross-reactivity was observed with any of the raw or clinically used gutta-percha products. In contrast the raw gutta-balata released proteins that were cross-reactive with Hevea latex. We conclude that the absence of gutta-percha proteins that can react with Hevea latex-specific IgE antibody supports the minimal potential for commercially available gutta-percha to induce allergic symptoms in individuals sensitized to NRL. Because gutta-balata is sometimes added to commercial gutta-percha products caution should be exercised if products containing gutta-balata are used in endodontic care of latex-allergic individuals.

Adult↗
PubMed1981

Mortality among rubber workers. III. Cause-specific mortality, 1940-1978.

This report describes mortality occurring between 1940 and mid-1978 among 29,087 men and women employed in a rubber plant for at least two years. Mortality patterns for the period July 1, 1974, to July 1, 1978, were compared to previously published findings for January 1, 1940, through June 30, 1974. Expected numbers of deaths were based on U.S. general population mortality data. There were excess deaths from bladder cancer and leukemia among white male union members during both follow-up periods. During recent follow-up of white male union members employed for at least five years, there were excesses in deaths from three additional cancers: esophageal cancer (11 observed/4.8 expected), biliary and liver cancer (6 observed/3.3 expected) and lymphoma and multiple myeloma (14 observed/5.8 expected). Evidence from other studies of rubber workers suggests that observed excesses in deaths from bladder cancer and leukemia are related to work-place exposures. The present findings suggest that occupational exposures etiologically relevant to these diseases may not have been reduced in recent years or that sufficient time has not elapsed for such reductions to result in decreased mortality. Further investigation is required to clarify the contribution of occupational factors to observed excesses in deaths form cancers of the esophagus and the biliary passages and liver and from lymphoma and multiple myeloma.

Aged↗
PubMed1999

An occupational cohort mortality study of women in the German rubber industry: 1976 to 1991.

Few previous studies of workers in the rubber industry have focused on women. We examined patterns of mortality among 2871 women employed in one of five German rubber plants for at least 1 year on or after January 1, 1976, and observed through December 31, 1991. All-causes mortality was near that expected (standardized mortality ratio [lsqbSMR], 101; 95% confidence interval [CI], 87 to 118), but cancer mortality was decreased (SMR, 90; 95% CI, 70 to 115). Nevertheless, excesses were observed for mortality from stomach cancer (SMR, 156; 95% CI, 63 to 322), lung cancer (SMR, 140; 95% CI, 56 to 289), and lymphatic system cancers (SMR, 175; 95% CI, 48 to 448). Stronger associations were observed among sub-cohorts defined by time period hired. Despite limited numbers of deaths, modest excesses of mortality due to specific cancers were observed and are consistent with previous studies.

Adult↗
PubMed1999

A meta-analysis of risk estimates for prostate cancer related to tire and rubber manufacturing operations.

Studies investigating the association between prostate cancer and exposure to the tire and rubber manufacturing environment have reported weak and inconsistent results. A meta-analysis of nine cohort studies that used standard mortality ratios and three case-control studies that used odds ratios was conducted. The pooled results from the nine cohort studies showed a standard mortality ratio of 101 (95% confidence interval [CI] = 93,110), whereas the pooled results from the three case-control studies showed on odds ratio of 1.10 (95% CI = 0.94, 1.29). The standard mortality ratios were converted to odds ratios by dividing by 100. The overall pooled risk estimate from all 12 studies was 1.03 (95% CI = 0.96, 1.11). The conclusion of this meta-analysis is that work exposure in a rubber and tire manufacturing environment does not result in an increased risk of prostate cancer.

Adult↗
PubMed2006

Evaluation of occupational exposure to N-nitrosamines in a rubber-manufacturing industry.

OBJECTIVE: We sought to determine volatile N-nitrosamines levels in the air of a rubber-manufacturing industry and to measure urinary N-nitrosamines concentrations in exposed workers. METHODS: Personal monitoring of 34 workers was performed by sampling nine airborne N-nitrosamines in four factories that manufactured rubber drive belts for automotive engines. Urinary N-nitrosamine levels were determined in all workers and in a control group of 26 subjects. Analyses were conducted by capillary gas chromatography-thermal energy analyzer. RESULTS: Airborne and urinary N-nitrosamines levels were very low and, in most cases, below the limit of detection (0.06 microg/m and 0.1 microg/L, respectively). CONCLUSIONS: Although airborne and urinary N-nitrosamines levels were found to be very low, exposed workers should still be monitored constantly because some of these substances are known to be genotoxic and carcinogenic.

Adult↗