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PubMed1998

Results of wearing test with two different latex gloves with and without the use of skin-protection cream.

A total of 109 subjects reporting symptoms indicating type I hypersensitivity reactions to natural rubber latex (NRL) gloves was included in this study, and 66 of them had latex-specific IgE antibodies. They underwent provocation tests by wearing two types of NRL gloves with high (n=103) and low (n=75) allergen contents. The first glove type caused positive skin reactions in 30% of IgE-positive and in 3% of IgE-negative subjects. After application of a commercially available skin protection (barrier) cream, the frequencies of positive skin responses in wearing tests increased to 41% and 7%, respectively. The gloves with low allergen content did not cause hypersensitivity without skin-protection cream but induced responses in 5% of IgE-positive subjects when this cream was applied. Corresponding findings were obtained in intraindividual comparisons of test results, which were possible in 69 cases. Of all wearing-test responders, 92% had latex-specific IgE antibodies. Our results demonstrate that high allergen contents in latex gloves frequently elicit skin responses in NRL-sensitized subjects, and that skin-protection creams may favor the uptake of allergens from gloves, thus increasing allergic reactions. The stipulation of a legally binding threshold limit value (TLV) for allergens in NRL products is urgently needed. This TLV should not be set above 2 microg allergen/g rubber.

Adult↗
PubMed1983

The effect of local scavenging on occupational exposure to nitrous oxide.

Despite evacuation of excess anaesthetic gases at the expiratory valve of the anaesthetic circuit and a general ventilation system producing 17-20 air changes per hour, mask anaesthesia often causes occupational exposure to anaesthetic gases exceeding the threshold limit values. The effect of a local air exhaust system, a local scavenger, on occupational exposure to nitrous oxide during paediatric mask anaesthesia was studied. The scavenger evacuated 140 m3 of air per hour and was placed at a distance of 20 cm from the face mask. In a very poorly ventilated operating theatre the exposure to nitrous oxide was reduced by 75% during the anaesthetic sessions and exposure to concentrations above 500 ppm was almost eliminated. The experiences from the installation and clinical use are discussed. Local scavenging is an excellent complement to the scavenging of excess gases at the expiratory valve, and it may be considered an alternative to expensive, high-capacity ventilation systems.

Air Conditioning↗
PubMed1995

Physiologically-based pharmacokinetic modeling of a mixture of toluene and xylene in humans.

A physiologically-based pharmacokinetic (PBPK) model for a mixture of toluene (TOL) and xylene (XYL), developed and validated in the rat, was used to predict the uptake and disposition kinetics of TOL/XYL mixture in humans. This was accomplished by substituting the rat physiological parameters and the blood:air partition coefficient with those of humans, scaling the maximal velocity for hepatic metabolism on the basis of body weight0.75, and keeping all other model parameters species-invariant. The human TOL/XYL mixture PBPK model, developed based on the quantitative biochemical mechanism of interaction elucidated in the rat (i.e., competitive metabolic inhibition), simulated adequately the kinetics of TOL and XYL during combined exposures in humans. The simulations with this PBPK model indicate that an eight hour co-exposure to concentrations that remain within the current threshold limit values of TOL (50 ppm) and XYL (100 ppm) would not result in significant pharmacokinetic interferences, thus implying that data on biological monitoring of worker exposure to these solvents would be unaffected during co-exposures.

Animals↗
PubMed1979

Neurasthenic symptoms in workers occupationally exposed to jet fuel.

Long-term exposure to petroleum distillation products (e.g. jet fuel) has been suggested to cause chronic mental and neurological symptoms. In the present "cross-sectional epidemiological study" the extent of neuropsychiatric ill-health in 30 workers exposed to jet fuel was compared with that in 60 non-exposed matched controls. Standardized medical interviews showed a higher occurrence of neurasthenic symptoms in exposed subjects (P less than 0.001). The result was confirmed by examination of the medical records kept by the factory physician (P less than 0.01). The prevalence of psychiatric symptoms was assessed with a rating scale of 37 items (a modified CPRS). Again, the exposed workers scored higher than the controls (P less than 0.001), particularly regarding the neurasthenic symptoms, i.e. fatigue, anxiety, mood changes, memory difficulties, and various psychosomatic symptoms (P less than 0.01). The results could neither be explained by observer's bias, nor by a greater susceptibility for mental disorders in the exposed subjects. We therefore conclude that occupational exposure to jet fuel vapours around the present threshold limit values may induce a neurasthenic syndrome.

Adult↗
PubMed1983

Psychiatric and neurological symptoms in workers occupationally exposed to organic solvents--results of a differential epidemiological study.

It is accepted knowledge today that repeated intoxication with organic solvents damages the central nervous system and causes persistent psycho-organic symptoms. That long-term but low-level occupational exposure--typical o painters and other blue-collar workers--can also induce such disorders has not generally been recognized. The present epidemiological study was undertaken to evaluate the possible neuropsychiatric effects of such exposure. 80 laquerers exposed to a mixture of industrial solvents (average hygienic effect 0.3) and 37 printers exposed almost only to toluene (average hygienic effect 1.0) were compared with a control group of 80 age-matched non-exposed subjects. In psychiatric interviews, the painters showed more mental symptoms. Fatigue, nervousness and lack of manual dexterity were most important and formed a typical neurasthenic syndrome. A general decrease in conduction velocity and action potential amplitude was also observed for the peripheral nerves. The printers showed a large decrease of the nerve action potential amplitude only for the sural nerve. No EEG abnormalities were found. Nor could any increase in mental symptoms be detected through psychiatric interviews compared to the controls. The results are interpreted as evidence for a CNS affection with consequent neuropsychiatric signs and symptoms after long-term occupational exposure to mixtures of industrial solvents below the current threshold limit values (TLV) but not after exposure to a single substance like toluene at about the TLV. The differential effects may be explained by synergistic amplification of the toxicity of solvent mixtures.

Adult↗
PubMed1995

An outbreak of occupational dermatosis in an electronics store.

An outbreak of skin disorders was noted by the primary care physician responsible for the health care of 52 employees in an electronics store. The cases occurred after termite treatment of the store, and the breakdown of the air-conditioning system in several areas in the store. Investigations were initiated to allay worker concern that the chemicals used for termite treatment (in particular, arsenic trioxide) were responsible for the outbreak. 9 of the 52 workers were found to have heat rash (miliaria rubra). 21% (7) of workers who worked in non-air-conditioned areas had heat rashes, as compared to 11% (2) of workers who worked in air-conditioned work zones. 2 workers had contact dermatitis due to exposure to greaseless lubricant, and 8 other workers had a non-work-related skin disorder. Indoor wet bulb globe temperature index measurements in the non-air conditioned areas were within threshold limit values, but ventilation in these areas was very poor. 2 environmental samples had non-detectable limits of arsenic.

Air Conditioning↗
PubMed1979

Levels of mercury and silver in dust from the trimming of amalgam dies.

The levels of mercury and silver in dust arising from the trimming, i.e. grinding, of amalgam dies in dental laboratories have been measured. In breathing air close to the workpiece, the mercury and silver contents exceeded the threshold limit values for short-term exposure by factors of aboit 60 and 400 in cases when local ventilation was not in use. With efficient local exhaust systems enabling a dust reduction of about 94%, the short-term exposure limit values for mercury and silver were exceeded by factors of about 4 and 20 respectively. Mercury and silver were assayed quantitatively by means of nuclear chemical analysis. A major part of the amalgam dust consisted of respirable particles. The collected dust comprised about 80% amalgam and 20% particulate matter from grinding wheels and stones according to SEM and EDAX measurements.

Air Pollutants↗
PubMed1984

Kinetics of white spirit in human fat and blood during short-term experimental exposure.

Seven volunteers were exposed to 100 p.p.m. white spirit (99% paraffins C8-C12) 6 hrs daily in 5 days. The mean concentration of white spirit after 5 days of exposure was 41.1 mg/kg fat (Friday afternoon). On the following Monday morning, the concentration was 31.7 mg/kg, i.e. only 23% had been eliminated during the exposure-free weekend. The estimated mean and median half-life was 7 and 8 days, respectively, elimination rate constant 0.0039 and 0.0036 hrs-1, time to reach steady state 5 to 8 weeks, maximal and minimal steady state concentration 85 and 66 mg/kg and 66 and 52 mg/kg, respectively. The concentration of white spirit in fat found each afternoon correlated significantly with the total dose. The concentration of white spirit/kg fat correlated positively with serum triglyceride and inversely with the percentage body fat (not significantly). The concentration of white spirit in the brain at steady state was estimated to maximum 11 mg/kg, while the half-life in the brain was estimated to maximum 18-19 hours. Minor differences occurred in the spectrometrical pattern produced by the in vivo biopsy evaporate as compared to in vitro specimens and white spirit vapours per se, thus indicating that the white spirit was slightly biotransformed or that the approximately 200 constituents of white spirit were absorbed differently. Thus, during exposure at the threshold limit value level, white spirit is accumulated in depot fat over weekends and in brain over working days. However, white spirit is almost eliminated from the brain during weekends.

Adipose Tissue↗
PubMed1985

Propyl ether. II. Pulmonary irritation and anaesthesia.

After cessation of the sensory irritation response, described in part one (Nielsen et al. 1985), a mixed response due to pulmonary irritation and anaesthesia appeared, resulting a decrease in respiratory rate and tidal volume. The corresponding thresholds were 1490 p.p.m. and 1280 p.p.m., respectively, obtained from the last half hour of a four hours exposure period. As the decrease in respiratory rate and tidal volume was found to be correlated, the per cent decrease in respiratory minute volume could be approximated from the square of the respiratory frequency. A threshold limit value (TLV) about 100 p.p.m. based on pulmonary irritation and anaesthesia was proposed. No impurities in the technical grade ether influenced the responses.

Anesthesia↗
PubMed1988

Pharmacokinetics of benzene in a human after exposure at about the permissible limit.

This limited range of experimental human exposure indicates that: 1. In the single experimental subject, the amount of benzene retained in the body 10 hours and more after exposure depends on the multiple of the concentration and duration of exposure. 2. At concentrations about the threshold limit value, the presence of other hydrocarbons does not affect the retention or elimination of benzene. 3. The amount of benzene retained in the body for 10 or more hours is dependent on the energy expenditure of the subject during exposure. There is reason to think that elimination after exposure is similarly affected. 4. While the principal route for elimination of benzene is the metabolite, conjugated phenol, in urine, the proportion eliminated in breath depends on the duration of exposure in the 1- to 8-hour range. 5. Three or four distinct compartments for retaining benzene are apparent and these may be identified with specific groups of organs in the body. 6. Mathematical modelling of the system can provide a reasonably accurate representation of benzene behavior in the body, and should enable dosage to individual or groups of organs to be estimated after occupational exposure. 7. Diurnal variation in the elimination of benzene after exposure may introduce a factor of uncertainty of about two into the prediction of exposure from biological monitoring. 8. Patterns of retention and elimination of toluene are very similar to those of benzene, though the principal metabolite in urine is different, and there may be a limit to the maximum amount that can be excreted by that route due to the relatively low solubility of hippuric acid in aqueous solutions.

Administration, Inhalation↗
PubMed1991

The Veterans Administration's Asbestos Abatement Program.

1. The Veterans Administration has developed a program of asbestos abatement for its more than 1000 buildings, where health care personnel from 173 hospitals and 238 ambulatory care clinics are likely to encounter respirable asbestos. 2. This is a costly program, which has averaged about $25 million annually for the past ten years. 3. The VA has banned the use of new asbestos products containing more than 1% of asbestos in building construction or renovation projects. 4. Industrial hygiene engineering programs have been ordered instituted at all VA medical centers to monitor dust levels in compliance with OSHA and EPA requirements. 5. Health surveillance programs, managed by an environmental health physician at each medical center, have been instituted for all personnel who have been identified to have breathed asbestos fibers in excess of OSHA-EPA threshold limit values. 6. The health care program focuses on the identification of asbestosis and asbestos-related cancer through periodic X-ray films, lung function tests, and electrocardiographic and physical examination screening. 7. The program also stresses cessation of smoking.

Air Pollution, Indoor↗
PubMed2006

Occupational exposure to acidic chemicals and occupational dental erosion.

OBJECTIVE: This study investigated the association between occupational acidic chemicals (ACs) exposure and occupational dental erosion. METHODS: A cross-sectional study was conducted in which three dentists surveyed 951 subjects from 42 factories using five types of ACs below Korean Threshold Limit Values (K-TLVs). Subjects agreed to participate by a written consent; 519 were acid exposed workers and 431 were non-exposed. The modified ten Bruggen Cate's criteria was used to classify erosion. Length and type of exposure to ACs were assessed using questionnaires. Logistic regression analysis including interaction terms was applied. RESULTS: ACs exposure was associated with erosion severity. Multiple exposures to ACs were found to be strongly associated with severe erosion. Interaction between wearing masks and AC exposure was significant. CONCLUSIONS: This study showed a clear association between AC exposure below K-TLVs and erosion. Hence, the authors propose to lower K-TLVs of five types of ACs.

Acids↗
PubMed1981

Changes in the c-wave of the electroretinogram and in the standing potential of the eye after small doses of toluene and styrene.

Low and moderate i.v. doses of toluene or styrene dissolved in a lipid emulsion (Intralipid) were given to cynomolgus monkeys. The d.c. ERG and the standing potential (SP) of the eye were recorded directly with corneal contact lenses, very stable calomel electrodes and under very constant general anaesthesia. Even small doses of the solvents, corresponding approximately to the Swedish hygienic threshold limit values for these solvents in air, clearly provoked slow variations with time in the amplitude of the c-wave of the ERG and in the SP level. Both potentials are generated mainly in the pigment epithelium. It is suggested that the effects reflect a direct influence of the solvents upon i.a. the cell membrane or the metabolism of the pigment epithelium.

Animals↗
PubMed1972

Carboxyhemoglobin elevation after exposure to dichloromethane.

Inhalation of dichloromethane vapor in concentrations of 500 to 1000 parts per million for 1 to 2 hours promptly initiated the formation of significant quantities of carbon monoxide in human subjects. The evidence suggests that carbon monoxide may be a metabolite of dichloromethane and, that exposure to concentrations of dichloromethane below the industrial threshold limit values may result in the formation of carbon monoxide in amounts that exceed the allowable limits.

Adult↗
PubMed1971

Phenol concentrations in the air from disinfection solutions.

Phenol concentrations in the air near phenol disinfectant solutions were measured. The concentration of phenol was not excessive, except for hot solutions with which exposure would normally be for a very short time. Adverse physiological reactions may occur at air levels below the threshold limit values which may be especially hazardous to those persons exposed to organisms causing respiratory diseases.

Air Pollution↗
PubMed1984

Removal of formaldehyde and xylene fumes from histopathology laboratories: a functional approach to the design of extraction systems.

There have been many reports of the relative hazards of formaldehyde, xylene, and hot paraffin wax fumes in pathology laboratories. In contrast, there have been comparatively few describing efficient extraction systems for their removal. When the opportunity presented to design a new laboratory the efficient removal of these fumes was given a high priority. In designing the extraction systems described consideration was given to the physical properties of the fumes and the degree of freedom of use of the bench, with the object of achieving sub-threshold limit values for each area of exposure. The efficiency of removal of the formaldehyde and xylene was measured using infrared spectroscopy.

Air Conditioning↗
PubMed1975

A follow-up study of coronary heart disease in viscose rayon workers exposed to carbon disulphide.

In 1967 two cohorts of 343 men each were formed and matched with respect to age, district of birth, and similarity of work. One cohort comprised viscose rayon workers with at least five years' exposure to carbon disulphide during any period between 1942 and 1967, and the other cohort consisted of workers from a paper-mill with no such exposure. The concentrations of carbon disulphide and hydrogen sulphide in the workroom air had been measured regularly since 1950, and about 4000 measurements were available. In all probability the concentrations had been very high in the 1940s, between 20 and 40 ppm in the 1950s, and about 10 to 30 ppm from 1960 onwards. On examination in 1967 it was confirmed that all of the relevant coronary risk factors had been kept under control. The only exception to this was blood pressure which was slightly higher among the exposed workers, a finding that was interpreted as a result of exposure rather than an independent risk factor. A five-year follow-up showed that 14 men had died from coronary heart disease (CHD) in the exposed group, against three in the control group (P smaller than 0:007). Other causes of death were evenly distributed. In addition, 11 nonfatal first infarctions had occurred in the exposed group as compared with four in the control group. On re-examination in 1972, nearly 25% of the exposed men, against 13% of the controls, had a history of angina (typical, probable, and possible) as measured by the World Health Organization questionnaire (P smaller than 0:0002). The prevalence proportions of typical angina were 12% and 5% respectively (P smaller than 0:001). As opposed to this, only slight differences were apparent for coronary ECGs. The higher degrees of prevalance in the exposed group may well have been attributable to chance. As in 1967/68, the mean systolic and diastolic blood pressures were slightly higher in the exposed group (P smaller than 0:001 and P smaller than 0:01, respectively). The relative risk was 4-8 for fatal attacks, 3-7 for all infarctions, 2-8 for nonfatal infarctions, 2-2 for angina, and 1-4 for ECG findings indicative of CHD. This implies that with increasing severity and specificity of the manifestations the causal role of CS2 in developing CHD becomes more evident. Further, it is inferred that exposure to CS2 seems to worsen the prognosis of CHD in addition to increasing its incidence. Although the exposure data in this study may not be representative of the personal exposure of the workers, the conclusion is drawn that a great deal of justification exists for lowering the threshold limit value of 20 ppm recommended by the American Conference of Governmental Industrial Hygienists.

Air↗
PubMed1975

Behaviour of rats exposed to trichloroethylene vapour.

Rats were exposed to trichloroethylene (TCE) vapour for about five five-day weeks at concentrations from 100 to 1 000 ppm, and at 100 ppm for 12 1/2 weeks. The social behaviour of paired male rats was observed periodically in the home cage for five minutes after they had been exposed to TCE. The principal finding was a consistent reduction of up to 24% in the total acitivity. A single day's exposure to TCE was sufficient at the highest concentration. At 100 ppm, a similar decline in activity was significant after 1 1/2 weeks' exposure in one experiment and 8 1/2 weeks' in another. The decline in activity was fairly uniform and not usually because of specific reductions in particular kinds of behaviour. However, exploration of the cage and submission to, or escape from, the other rat were sometimes specifically reduced. In an 'exploration-thirst' test, rats were deprived of water overnight and placed on two or three occasions in a previously unfamiliar cage. Rats exposed to 100, 200, or 1 000 ppm TCE found water and began drinking sooner than their controls without altering the rate of movement about the cage. These results suggest lowered performance in a familiar situation where rats are usually very active and some loss of inhibitory control in an unfamiliar one. At the present threshold limit value, repeated exposure to TCE eventually had effects similar to those of one day's exposure to a higher concentration, but only after a widely variable delay.

Aggression↗