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PubMed2003

Identification of extractable substances from rubber nettings used to package meat products.

Ten meat nettings were sampled from four different suppliers in the Netherlands. These meat nettings consisted both of natural rubber and of vegetable fibres. Nitrosamines were extractable up to 2 mg x kg(-1) netting, the nitrosamine being N-nitrosodibenzylamine. The nitrosatable substances found were precursors of N-nitrosodimethylamine and N-nitrosodibenzylamine and were extracted up to 0.4 mg x kg(-1) nettings. Considering the ratio of meat netting and foodstuff, the extractable amount of nitrosamines and nitrosatable substances does not raise concern for public health. The meat nettings were also screened for other potential migrants. Extractable amounts of several alkanes, alkenes, acids, antioxidants, plasticizers and sterols were found. Several of these extracted substances are not allowed in the Netherlands, although some are authorized in other countries. Several substances, however, have not been evaluated for use in food-contact materials and therefore the possible risk to public health is unknown.

Animals↗

PubMedDate not supplied

Cancer risk among rubber workers.

Studies of the cancer risk among rubber workers published since 1968 are reviewed. The total material examined comprised 80,000 workers and 4000 cancer deaths. An increased risk of stomach cancer, lung cancer, bladder cancer, and leukemia was found. The increased risk of cancer at a specific anatomic site was correlated with the mode of exposure specific for the working area or division. On the other hand, no clear exposure-risk relationship could be demonstrated. It is likely that there has been an increased risk of cancer since the elimination of alpha- and beta-naphthylamine by 1950. However, the etiologic fraction is less than that due to prevalent exposures increasing the risk of common cancers at specific anatomic sites.

Humans↗

PubMed1984

Determination of N-nitrosamines and N-nitrosamine precursors in rubber nipples from baby pacifiers by gas chromatography-thermal energy analysis.

N-Nitrosamines and precursors are present in rubber products in which the accelerators and stabilizers used in the vulcanization process were derived from dialkylamines. Research was performed to develop data concerning the presence of N-nitrosamines and precursors so that the health significance of the exposure problem related to infant ingestion of these chemicals could be properly assessed. Volatile N-nitrosamines were determined in cut-up pacifier nipples by extraction with dichloromethane followed by concentration in a Kuderna-Danish evaporator, high-temperature mineral oil purge and trap, and analysis by gas chromatography--thermal energy analysis (GC-TEA). N-nitrosodibutylamine (NDBA) was the principal N-nitrosamine found, with concentrations up to 427 ppb. N-Nitrosamines and precursors in cut-up and intact nipples were determined by GC-TEA after a single extraction with artificial saliva. NDBA was the principal nitrosamine found, at levels up to 1040 ppb, while dibutylamine (DBA) was the principal precursor found, at levels up to 3890 ppb. The persistence of these compounds in intact nipples was determined by multiple artificial saliva extractions. Amounts of NDBA and DBA found after 15 artificial saliva extractions of intact pacifier nipples totalled 824 ppb and 15.6 ppm, respectively. N-Nitrosamine levels generally showed a gradual decrease in concentration with each extraction, whereas no consistent trend could be determined for concentrations of precursors.

Bottle Feeding↗

PubMed1980

Worker exposures to chemical agents in the manufacture of rubber tires: solvent vapor studies.

Environmental sampling surveys have been conducted in ten large tire manufacturing plants across the U.S. to characterize the nature and intensity of current exposure to solvent vapors. These plants were chosen to represent a cross-section of the industry and include both old and new plants, plants of four different companies and plants with wide geographic distributions. A variety of organic solvents is used in the manufacture of tires and tubes; accordingly solvent vapors comprise one category of exposure for workers in specific Occupational Title Groups (OTGs). Approximately 1000 determinations of various solvent vapor components in air samples have been made with special emphasis on pentane, hexane, heptane, benzene and toluene vapor levels. Exposures stem from the widespread use of bulk materials including petroleum naphthas, gasoline and aliphatic and rubber solvents in various tire manufacturing operations.

Air↗

PubMed1982

Determination of carbon black on silver membrane filters from rubber factory dust.

The NIOSH criteria document for carbon black cites a method for the determination of carbon black in the workplace atmosphere by membrane filter collection and weighing of the particulates. If particulates other than carbon black are present, they will be determined along with carbon black giving false high measurements for carbon black. All manufactured rubber articles, including tires, contain a wide variety of organic and inorganic additives, which may be present in the workplace atmosphere. These particulates must be separated from carbon black before an accurate determination of the amount of carbon black can be made. The proposed method solves this problem by removing organic additives from a silver membrane filter with organic solvents, heating the filter to 550 degrees C to remove only carbon black and determining the remaining inorganics by a final weighing of the filter. Not only can carbon black be determined by this method but the amount of organic and inorganic additives also can be evaluated.

Carbon↗

PubMed1983

Rubber manufacture: sampling and identification of volatile pollutants.

Volatile pollutants produced from several rubber goods manufacturing processes were sampled and analyzed. Samples were collected in the vulcanization areas of a shoe-sole factory, a tire retreading operation, and also in the extrusion areas of the retreading operation and an insulated cable manufacturer. Volatile organics from the vulcanization and extrusion operations were collected on activated charcoal, desorbed with trichlorofluoromethane and analyzed by GC/MS. Approximately 100 different compounds were identified and quantitated; their cumulative concentrations ranged from 25 to 27000 micrograms/cubic meter.

Air Pollutants↗

PubMed1996

Worker exposures to nitrosamines in a rubber vehicle sealing plant.

Occupational nitrosamine exposures were measured during a National Institute for Occupational Safety and Health (NIOSH) health hazard evaluation at a rubber vehicle sealing plant. All of the 28 personal breathing zone samples had detectable concentrations of nitrosodimethylamine (NDMA), nitrosodiethylamine, nitrosopiperidine (NPIP), and nitrosomorpholine; and 27 of the 28 samples had detectable concentrations of nitrosopyrrolidine. The NDMA exposures were the highest, ranging from 0.47 to 11.44 micrograms/m3. The next highest exposures were to NPIP, ranging from 0.20 to 4.39 micrograms/m3. Several general area air samples were also collected, which revealed concentrations of NDMA ranging from 2.29 to 88.47 micrograms/m3 at the drills along the salt bath lines. The salt bath curing process appears to be the primary source of nitrosamine formation, and personal exposures were highest for the salt bath line operators and assistant operators. Although there are no numerical occupational nitrosamine standards in the United States to reference, the exposures in this plant were much higher than the German standard of 1 micrograms/m3 total nitrosamines for general industry and 2.5 micrograms/m3 total nitrosamines for certain processes such as vulcanization. NIOSH investigators recommended that the ventilation systems be improved to reduce the exposures to the lowest feasible concentrations until the process can be redesigned so that nitrosamines are not formed.

Air Pollutants, Occupational↗

PubMed1996

Selenium levels in the serum of workers at a rubber tire repair shop.

Selenium analysis by neutron activation was performed on serum samples taken from 20 workers at a rubber tire repair shop and from a control group of 18 healthy persons. The mean values were: 148 +/- 56 (70-296) and 100 +/- 18 (70-127) micrograms/L for the tire workers and the control groups, respectively. The difference between mean values was significant (p < 0.01). A high correlation (r = 0.82) was obtained between selenium level and seniority for those values higher than the control group range. None of the shop workers showed evidence of selenosis.

Adolescent↗

PubMed2004

Historical estimation of exposure to 1,3-butadiene, styrene, and dimethyldithiocarbamate among synthetic rubber workers.

Quantitative estimates of exposure to 1,3-butadiene (BD), styrene (STY), and dimethyldithiocarbamate (DMDTC) were developed for a follow-up study of workers at six North American synthetic rubber plants. Procedures entailed identifying tasks and jobs involving exposure, identifying factors influencing historical changes in exposure potential, and using mathematical models to calculate job- and time-period-specific exposures. Exposure metrics included 8-hour time-weighted average (TWA) intensity, the annual number of peak exposures (BD: >100 ppm, STY: >50 ppm) and TWA intensity below and above the peak threshold. The 5th and 95th percentiles of the approximate probability distribution of each exposure estimate served as its 90% uncertainty interval. Job- and year-specific estimates were linked with subjects' work histories to obtain cumulative exposure indices. Exposure estimates varied among tasks, jobs, plants, and time periods. BD TWAs were approximately 10 ppm during the 1940s-1960s and declined during the 1970s and 1980s. STY TWAs were always <2 ppm. DMDTC exposure began in the 1950s, was high through the 1960s, and later declined. BD peak exposure accounted for a large proportion of cumulative BD exposure, whereas almost none of the STY exposure was experienced at levels >50 ppm. Exposure indices were correlated. Exposures were higher than previously estimated. Multiple correlations among DMDTC, BD, and STY exposure estimates make it difficult to estimate agent-specific effects. Limitations of the methodology include the potential inaccuracy of the estimates, the lack of adequate industrial hygiene data to validate the estimates, the additional inaccuracy of linkage with poorly specified job groups, and the potential for differential exposure misclassification because the jobs and work areas where excess leukemia mortality occurred were well-known at the time of this study. Nevertheless, the new exposure estimates were highly correlated with the old, yielding equivalent exposure ranking of workers and were comparable to limited industrial hygiene data published by NIOSH.

Butadienes↗

PubMed2002

ELISA inhibition assay for the quantitation of antigenic protein in natural rubber latex.

Evaluating allergenicity of natural rubber latex (NRL) products is essential for the successful reduction of the consumer's exposure to potentially allergenic NRL proteins. We have developed an ELISA Inhibition method for the quantitation of extractable proteins from NRL products which has good sensitivity and specificity. The method utilizes rabbit anti-NRL protein serum as a detection mechanism. The source of NRL proteins for immunization and as a reference protein in the assay is ammoniated raw latex (AL). By comparison with the Western blot analysis of the rabbit sera, it appears that the ELISA detects most of the latex proteins present in extracts. To investigate, further, this assumption, we compared the ELISA Inhibition test with two other methods for total protein measurement. We also compared the values generated by the ELISA Inhibition test with other immunological methods for quantitation of antigenic and allergenic proteins. Comparisons were performed with 15 extracts from randomly selected surgical and examination gloves. The samples were coded separately for each test to insure the objectivity of evaluation. The antigenic protein values obtained by the ELISA Inhibition test correlated best with the HPLC amino acid analysis (correlation coefficient (cc) = 0.79) and with the LEAP assay (cc = 0.97). The antigenic protein levels obtained by the ELISA test were 3-10 times lower than those obtained by the HPLC analysis. A lesser correlation was observed with the Modified Lowry assay (cc = 0.45), which is likely due to chemical interference bias in the Lowry method. Our findings suggest that the antigenic proteins measured by the ELISA Inhibition test described here more closely represent the measure of the total protein content in the extracts. It is important to note that the relative values obtained by this method are lower than the values obtained by other total protein methods, possibly due to a large number of small peptides present in NRL products, that would only be measured by the chemical method.

Animals↗

PubMed2002

Identification of antigenic and allergenic natural rubber latex proteins by immunoblotting.

Quantitation of proteins in finished natural rubber latex (NRL) products is essential in predicting their allergenic potential. The ASTM standard Modified Lowry method for measuring total protein content has been used for several years. Most recently, ASTM published a standard for more sensitive and more specific enzyme immunoassay for quantitation of antigenic NRL proteins. It is an ELISA inhibition assay, using rabbit anti NRL sera. Since the measurement of proteins in this method depends on recognition capacity of rabbit antibodies, the selection of an appropriate protein source for rabbit immunization is crucial for the accuracy of such test. In this study, we evaluated the composition of NRL proteins from ammoniated (AL) and nonammoniated (NAL) raw latex and from finished NRL products, and compared the effectiveness of sera from rabbits immunized with NRL proteins, to react with those extracts. Immune rabbit sera were analyzed by immunoblotting against extracts of several samples of AL, NAL, and glove proteins. In the NAL extracts, we identified 26-28 protein bands by SDS-PAGE. AL samples had between 6 and 9 bands with a great variation in the band positions among the samples. The Western blot analysis showed that anti-AL rabbit serum reacted with 4-9 protein bands in various AL extracts. The highest intensity of reaction was observed with the extract used to immunize the rabbits. Similar reaction was observed with anti-NAL serum. However, when the antisera were blotted against NAL extracts, anti-NAL serum reacted more strongly and with a larger number of proteins than anti-AL serum. In summary, anti-NAL serum recognized an equal number of proteins in AL extract as anti-AL serum. However, anti-AL serum recognized fewer protein molecules in NAL extract than anti-NAL serum. Our findings suggest that NAL extract contains more individual proteins than other extracts, and sera from rabbits immunized with this antigen have a greater capacity to react with a wide spectrum of NRL proteins. This finding may be helpful in selecting the representative reference antigen and antiserum for further efforts in NRL protein quantitation.

Allergens↗

PubMed1996

Advantage of rubber over plastic endotracheal tubes for rapid extubation in a laser fire.

The occurrence of airway fires during laser airway surgery necessitates the use of special techniques to improve patient safety. For example, it is recommended that the endotracheal tube cuff be inflated with saline. However, in the event of an endotracheal tube fire, the tube must be quickly removed. This study was designed to determine the time necessary for red rubber (RR) or polyvinylchloride (PVC) endotracheal tubes to be removed from a model airway after inflating the cuffs with saline. A model larynx and trachea was suspended vertically. It was intubated with either 7.0 RR or PVC endotracheal tubes. Six milliliters of saline was used to inflate the endotracheal tube cuffs. After inflation, a clamp was used to occlude the pilot tube on the RR endotracheal tubes. A 4-lb weight was then suspended from the endotracheal tube. The time to spontaneous extubation of the model trachea after unclamping the pilot tubes on 12 RR endotracheal tubes was determined. For the PVC endotracheal tubes, the times to spontaneous extubation using the 4-lb weight were determined in 12 endotracheal tubes after cutting the pilot tube and in 12 by maximum aspiration of the saline from the endotracheal tube cuff with a 10-ml syringe. A time of 0.94 +/- 0.10 sec (mean +/- SD) was required for spontaneous extubation of the RR endotracheal tubes after unclamping the pilot tube. For the PVC endotracheal tubes, extubation occurred 3.28 +/- 1.08 and 1.81 +/- 0.60 sec after cutting the pilot tube or deflating the cuff with a syringe, respectively. The mean times for each of the 3 groups were significantly different (p < 0.05) from each other as determined by the ANOVA. This study shows that if PVC endotracheal tubes are used, deflation of the saline-filled cuff by aspiration with a 10-ml syringe is faster than cutting the pilot tube. Unclamping the pilot tube on the RR endotracheal tubes resulted in the fastest time to endotracheal extubation.

Analysis of Variance↗

PubMed2004

Longitudinal study of sensitization to natural rubber latex among dental school students using powder-free gloves.

BACKGROUND: A high rate of sensitization and clinical allergy to latex proteins has been reported in health care personnel. This is thought to be due to increased occupational exposure especially to natural rubber latex (NRL) gloves with an estimated prevalence varying widely (2.8-18%). OBJECTIVE: This was a longitudinal study to monitor a cohort of first-year dental students throughout 4 study years during exposure to powder-free gloves. Their atopic status was determined by skin prick testing using a panel of common allergens, and any sensitivity to latex proteins and the cross-reacting food allergens assessed. METHODS: Skin prick testing was carried out on the volunteers using latex, avocado, kiwi, banana, grass pollens, tree pollen, house dust mite and cat dander. Each volunteer completed a questionnaire detailing allergic history and any previous latex exposure. RESULTS: Skin prick testing showed a 65% incidence of atopy in the longitudinal study group. Initial latex skin testing was positive in 3 of the 63 students followed throughout their period of study. Subsequent testing gave a negative result in one student and one declined retesting. The third continued to give a positive response on each testing; she wore only nitrile gloves and remained free of clinical NRL allergy symptoms. No student developed latex sensitivity during the 5 yr of this study. CONCLUSION: Exposure to powder-free latex gloves was not associated with subsequent sensitization over 5 yr in a population with a high atopic incidence.

Allergens↗

PubMed1977

Investigations of some aspects of atmospheric pollution by anaesthetic gases. I: Diffusion of halothane across plastic and rubber tubes.

Plastic and rubber tubing, of the types used frequently to convey anaesthetic gases to and from the patient, or anaesthetic waste gases out of the operating theatre, were assessed for their capacity to allow diffusion of halothane through the tube wall. The magnitude of this effect has been calculated in relation to pollution of the operating theatre atmosphere under different circumstances.

Air Pollution↗

PubMed1987

Rapid method for the detection and quantification of N-nitrosodibutylamine in rubber products.

A rapid method for the detection and quantification of N-nitrosodibutylamine (NDBA) migrating from rubber products into a neutral buffer solution is described. The extraction, clean up, and concentration is done by a one-step procedure using C18 cartridges. NDBA in the ppb range is identified and quantitated by gas chromatography (GC) with a thermal energy analyzer (TEA) as detector.

Chromatography, Gas↗

PubMed2004

Bladder tumours in rubber workers: a factory study 1946-1995.

BACKGROUND: Prior to December 1949, some British rubber industry workers were inadvertently exposed to the human bladder carcinogen beta-naphthylamine, which was present as a contaminant (at 0.25%) in antioxidants used in manufacturing. This study follows a composite cohort of 6450 men employed at a large tyre factory either during the 'at-risk' period or just after it. METHODS: A group of 2090 at-risk men (employed 1945-1949) and 3038 men, first employed only after January 1950, when the carcinogen had been removed, were followed for their bladder cancer morbidity and mortality experiences. RESULTS: Fifty-eight tumours were registered for those at risk, whereas only 33.9 were expected at national standardized registration rates [SRRN = 171 and 95% confidence interval (CI) = 130-221]. Thirty-nine bladder tumours were reported for the post-1950 intake, whereas 38.3 were expected (SRRN = 102 and 95% CI = 72-139). The use of mortality data did not reveal any underlying hazard because 12 of the 58 at-risk workers with tumours were still alive at the study end date. In only 16 instances was bladder cancer actually certified as the underlying cause of death. Plotting cases by their location of work on a factory plan assisted the interpretation. CONCLUSIONS: A statistically significant elevated risk of bladder cancer for the exposed workforce was evident, but this reversed when the carcinogen was removed from processing in October 1949. The use of morbidity (incidence) data in long-term studies of occupational bladder cancer should be the required methodology if the hazard and risk are not to be underestimated.

2-Naphthylamine↗

PubMed1976

Mortality among rubber workers. I. White male union employees in Akron, Ohio.

Mortality among a cohort of 13,571 white male rubber workers in Akron, Ohio is described. Mortality from all causes was 82% of that expected on the basis of death rates for US white males. Excess deaths from cancer (observed/expected numbers) in specific sites among workers in specific work areas include stomach:processing (18/9.9); large intestine: processing (14/10.5); lung: tire curing (20/12.4): bladder: all workers (48/39.5); brain: tire building (7/3.7): lymphatic: tire building (11/7.1): and leukemia: all workers (55/43.0). In general, excess cancer deaths occurred most often among men who started working between ages 35 and 44 and prior to 1935, who worked 25-34 years and were over age 74 at death, and who died after 1954.

Adult↗

PubMed1999

When a rubber hand 'feels' what the real hand cannot.

We examined a patient who was clinically much better at reporting tactile stimulation when he could see his stimulated hand. Experimentally, we found that he had difficulty detecting taps accompanied by a salient (but not predictive) light located directly above his concealed hand. However, his performance was dramatically improved if the light was attached to a rubber hand situated in line with the patient's hidden hand. Previous studies have suggested that tactile sensitivity can be improved by nearby visual stimulation. However, our effect shows that crossmodal sensory facilitation does not only depend upon simple spatial proximity alone. Rather, a simultaneous visual event dramatically improves perception of touch specifically when it is attributed to the perceiver's stimulated limb.

Functional Laterality↗