Laboratory work and pregnancy outcome

Spontaneous abortions among women working in laboratories, and congenital malformations and birth weights of the children were examined in a retrospective case-referent study. In the spontaneous abortion study there were 535 women (206 cases and 329 referents), and in the malformation study 141 women (36 cases and 105 referents). The analysis of the birth weights concerned 500 women (referents). Significant associations with spontaneous abortion were found for exposure to toluene (odds ratio [OR], 4.7, 95% confidence interval [CI], 1.4 to 15.9), xylene (OR 3.1, CI 1.3 to 7.5) and formalin (OR 3.5, CI 1.1 to 11.2) > or = 3 days a week, adjusted for the covariates. Most of the women exposed to formalin and xylene were working in pathology or histology laboratories. No association with congenital malformation was found.

Cerebellar atrophy related to chronic exposure to toluene. Case report

A 31-year-old woman presented slowly progressing ataxia and neurasthenic symptoms after 14-year occupational exposure to low concentration toluene vapour. Examination disclosed only cerebellar signs. Cognitive functions were normal except moderate visuo-spatial and constructive deficit. CT imaging showed severe pancerebellar atrophy without pathological signs in other brain structures. Two years after she was removed from workplace, CT imaging and ataxia showed no worsening, while visuo-constructive function improved. The authors warn against possible neurotoxic risk associated with this kind of exposure.

Toluene embryopathy: clinical delineation and developmental follow-up

OBJECTIVE

To expand the phenotype of toluene embryopathy.

METHOD

Review of case records of 35 deliveries with antenatal exposure to toluene. Six children were examined and their features are compared with previously reported cases.

RESULTS

There were three perinatal deaths. Of the survivors, review of available data revealed a high incidence of prematurity (42%), low birth weight (52%), and microcephaly (32%). Birth weight, length, and head circumference and gestational length were significantly less than a control group closely matched for gender, race, and socioeconomic status. Follow-up pediatric evaluation revealed growth retardation (46% < 5th percentile for weight, 38% < 5th percentile for height), microcephaly (46%), and developmental delays (38%). Maternal toluene abuse of 4 or more years was positively correlated with weight < 5th percentile and microcephaly in childhood. The six children examined demonstrated many previously described features of toluene embryopathy including microcephaly, narrow bifrontal diameter, short palpebral fissures, hypoplastic midface, wide nasal bridge, abnormal palmar creases, and blunt fingertips. Only one of the six children examined had antepartum exposure to alcohol as well as toluene.

CONCLUSION

In utero exposure to toluene seems to be associated with teratogenicity in the developing fetus. A preliminary picture of toluene embryopathy is now emerging.

Toluene Embryopathy: Delineation of the Phenotype and Comparison With Fetal Alcohol Syndrome

Objective. To determine if maternal toluene abuse produces any structural or developmental disabilities in the developing fetus, a cohort of toluene-exposed infants was ascertained and examined.

Methodology. Eighteen infants with a history of in utero toluene exposure were examined at birth. Nine of these infants were reexamined 3 to 36 months after their initial evaluations. The clinical findings in these patients were compared with those of similarly exposed children from the literature and with patients who had the fetal alcohol syndrome.

Results. Thirty-nine percent of all toluene-exposed infants described in this and other studies were born prematurely, and 9% died during the perinatal period. Fifty-four percent were small for gestational age, and 52% exhibited continued postnatal growth deficiency. A 33% incidence of prenatal microcephaly, a 67% incidence of postnatal microcephaly, and an 80% incidence of developmental delay were observed. Eighty-three percent of the patients had craniofacial features similar to the fetal alcohol syndrome, and 89% of these children had other minor anomalies.

Conclusions. Data from the patients herein described and the available scientific literature suggest that the mechanism of alcohol craniofacial teratogenesis may be nonspecific, with a variety of teratogens, including toluene, giving rise to phenotypic facial abnormalities similar to those of the fetal alcohol syndrome. We propose a common mechanism of craniofacial teratogenesis for toluene and alcohol, namely a deficiency of craniofacial neuroepithelium and mesodermal components due to increased embryonic cell death.

Exposure of workers to a mixture of toluene and xylenes. II. Effects

The health effects of exposure to a mixture of toluene and xylene isomers was studied on the fourth or fifth days of a working week in factories in China. The study population comprised 233 subjects (122 men and 111 women), who were exposed to the time weighted geometric mean (maximum) concentrations of toluene (3 (203) ppm) and xylenes (4 (103) ppm). For comparison, 241 non-exposed controls (116 men and 125 women) were recruited from the same regions. The prevalence of some subjective symptoms significantly increased in the exposed population, and the symptom profiles were similar to those found after exposure to toluene or xylenes alone. Haematology and serum biochemistry did not show notable changes. It seems reasonable to conclude that the effects of the toxicities of toluene and xylenes in combination are additive.

[Occupational exposure and individual factors influencing urinary elimination of hippuric acid]

The influence of not occupational factors (smoking, alcohol, coffee, drugs, sport, sex, age and body weight) on hippuric acid excretion was analyzed in two groups of healthy male subjects. A group was constituted of 710 painters occupied in wood and coach workings and the other one of 109 not occupational. The 5 degrees, 50 degrees, 95 degrees percentiles of the two distribution were 208, 605, 1784 and 153, 538, 1700 mg/g creatinine respectively. The analysis of variance undertaken on exposed subjects showed that there was a significative difference between urinary hippuric acid levels of subjects consuming alcohol and the not ones. Multiple regression analysis on hippuric acid excretion values distribution in not exposed group showed that only the variable "coffee consumption" resulted statistically significative (Ln hippuric acid = 5.0287 + 0.8062; R2 = 01221). Coffee consumption increase excretion rate (mg/hour) of hippuric acid likely an exposure to a toluene air concentration of 50 mg/m3. The authors suggest an action of caffeine on endogenous amount of benzoic acid.

Acute toxicity of gasoline and some additives

The acute toxicity of gasoline; its components benzene, toluene, and xylene; and the additives ethanol, methanol, and methyl tertiary butyl ether are reviewed. All of these chemicals are only moderately to mildly toxic at acute doses. Because of their volatility, these compounds are not extensively absorbed dermally unless the exposed skin is occluded. Absorption through the lungs and the gastrointestinal tract is quite efficient. After ingestion, the principal danger for a number of these chemicals, particularly gasoline, is aspiration pneumonia, which occurs mainly in children. It is currently not clear whether aspiration pneumonia would still be a problem if gasoline were diluted with ethanol or methanol. During the normal use of gasoline or mixtures of gasoline and the other solvents as a fuel, exposures would be much lower than the doses that have resulted in poisoning. No acute toxic health effects would occur during the normal course of using automotive fuels.

Serum laminin, hydrocarbon exposure, and glomerular damage

It has been postulated that occupational exposure to hydrocarbons may damage the kidney and lead to glomerulonephritis and chronic renal failure. As laminin is a ubiquitous basement membrane component that seems to play a central part in the structure and function of basement membranes and as the normal renal filtration process is highly dependent on an intact glomerular basement membrane, the serum laminin concentration was examined in a population of workers exposed to hydrocarbons. The hydrocarbon exposure was assessed by exposure surrogates (exposure duration and exposure score). An interaction between occupational exposure to hydrocarbons and hypertension increased the laminin concentration whereas the laminin concentration decreased in workers exposed for a long time probably because of a selection effect. In a subgroup of printers exposed to toluene whose hippuric acid excretion had been recorded for several years this interaction was confirmed when the hippuric acid excretion was substituted for the other exposure indices. In the exposed group, the age-related decline in creatinine clearance was accelerated. These results seem to confirm that occupational exposure to hydrocarbons is a non-specific factor that may promote a deterioration of renal function.

Detection and measurement of S-benzyl-N-acetylcysteine in urine of toluene sniffers using capillary gas chromatography

We examined the urinary excretion of S-benzyl-N-acetylcysteine (SBAC) of toluene sniffers using capillary gas chromatography. SBAC was extracted from 10 ml urine with chloroform and backextracted into 1 M sodium bicarbonate solution. After acidification, the aqueous solution was reextracted with ethyl acetate, and then derivatized to its methyl ester (ME). The peak appearing in the gas chromatogram was identified as SBAC-ME by mass spectrometry. The calibration curve was constructed by plotting the peak height ratio of SBAC-ME and internal standard (S-phenethyl-N-acetylcysteine)-ME against analyte concentration using 10 ml toluene unexposed urine. It showed good linearity over the range of 0.05-3.0 mg/l (r = 0.99). We have applied this technique to urine samples from toluene sniffers. SBAC was detected in all urinary samples of sniffers (n = 30, 0.11-47.13 mg/l), but not at all in the urine of toluene unexposed subjects (n = 60). These results prove that SBAC is also formed from toluene by human metabolism, and detection of SBAC is considered a useful marker for inhalation of toluene.

Acute fatty liver of pregnancy after exposure to toluene. A case report

We describe a patient in whom acute fatty liver of pregnancy developed after long-term toluene exposure. Acute fatty liver of pregnancy was documented by a liver biopsy specimen stained with oil red O and observed under electron microscopy. Although the mother did well, she gave birth to a stillborn whose autopsy showed visceral congestion and placental infarction. This case raises the hypothesis of a possible relationship between toluene exposure and acute fatty liver of pregnancy.

Urinary D-glucaric acid, a marker substance for microsomal enzyme induction. Methodological aspects, responses to alcohol and findings in workers exposed to toluene

D-glucaric acid, an end product of glucuronic acid metabolism, has been used as a marker substance for microsomal enzyme induction. In this study a convenient microtitre-plate based method for the quantification of urinary D-glucaric acid has been developed and validated. Mean urinary D-glucaric acid excretion in 20 health humans as measured by this method was 3.2 mumol glucaric acid mmol-1 creatinine, 95% confidence interval 3.0-3.4. Moderate alcohol consumption in 18 healthy volunteers did not significantly augment the urinary D-glucaric acid excretion. Occupational exposition to toluene in a printing plant was investigated. In spite of considerable intra- and inter-individual variability, a significant difference between exposed (3.5, 3.1-3.9) and non-exposed (2.6, 2.2-3.0) workers was observed, p < 0.025. We conclude that the measurement of D-glucaric acid can be utilized for biological screening of enzyme induction on a group basis.

Clinical efficacy of 'essential' phospholipids in patients chronically exposed to organic solvents

A total of 45 workers, who had been chronically exposed to a potentially hepatotoxic xylene-toluene-benzene mixture in the atmosphere, were treated for 3 months with 'essential' phospholipids. Routine biochemical tests and radioisotope investigations to assess liver damage were carried out both at baseline and after treatment. The liver:spleen index was increased in 71% of subjects and the mean isotope transit time in the liver was reduced in 90% of the patients after treatment. The biochemical parameters remained within the normal range throughout the treatment period. The results suggest that 'essential' phospholipids may be of value in the treatment of liver damage that has arisen as a result of chronic exposure to organic solvents.

Somatosensory evoked potentials in workers exposed to toluene and styrene

Somatosensory evoked potentials (SEPs) were used to evaluate possible subclinical impairment of the nervous system due to occupational exposure to toluene and styrene. A group of 36 rotogravure printers with severe exposure to toluene, 20 workers with severe exposure to styrene in a glass laminate manufacturing plant, and a comparison group of healthy subjects were studied. The severity of exposure was documented by measurements of toluene and styrene concentrations in breathing zone air, by hippuric acid concentration in urine in the group exposed to toluene, and by urinary mandelic acid concentration in the group exposed to styrene. Somatosensory evoked potentials were measured by stimulation of the median nerve at the wrist and the tibial nerve at the ankle. Peripheral conduction velocities (CVs) in both extremities and central conduction time (CCT) after tibial nerve stimulation were significantly decreased in both exposed groups. Significantly prolonged latencies of peripheral and cortical SEPs to median nerve stimulation as well as cortical SEPs to tibial nerve stimulation were found in workers exposed to styrene. Some abnormalities in SEPs at peripheral or spinal and cortical levels were found in eight workers exposed to toluene and six workers exposed to styrene. Of these, in three workers exposed to toluene and two to styrene increased CCT and delayed latencies of cortical responses at normal conduction values in the periphery were found. A trend for increased frequency of abnormal SEPs with duration of exposure to toluene and styrene and alcohol abuse was found. Abnormalities in SEPs in the exposed groups are most probably of multifactorial origin. Central SEP abnormalities in both exposed groups could indicate early signs of subclinical dysfunction at spinal and cortical levels and could be due to toluene or styrene exposure probably potentiated by alcohol consumption in the group exposed to toluene.

Allergic contact dermatitis from color film developers: clinical and histologic features

We evaluated two patients with allergic contact dermatitis that resulted from exposure to color film developers. A lichenoid eruption developed in one patient, whereas an eruption more characteristic of an acute spongiotic dermatitis developed in the second patient. Histologic findings in the first case were those of a "lichenoid dermatitis" but with features distinct from classic lichen planus. The biopsy specimens from the second patient showed a subacute spongiotic process with a bandlike infiltrate suggestive of an evolving lichenoid process. Contact allergy to color developers may result in eruptions similar to lichen planus. This process appears to evolve from an acute spongiotic dermatitis in its early phase to a lichenoid dermatitis in fully developed and more chronic forms. Although the histologic features are those of a "lichenoid" dermatitis, some features, such as the presence of spongiosis, eosinophils, and a less intense inflammatory infiltrate, may enable distinction between lichenoid allergic contact dermatitis and true lichen planus. In addition, clinicopathologic correlation with patch test results should permit accurate diagnosis in most cases.

Dentist's occupational allergic contact dermatitis caused by coconut diethanolamide, N-ethyl-4-toluene sulfonamide and 4-tolyldiethanolamine

Dental personnel are exposed to many sensitizing compounds at work and often develop multiple delayed allergies. Here we report on a dentist who got sensitized to several products that have not, or only seldom, caused sensitization earlier. These products were: coconut diethanolamide from her handwashing liquids, N-ethyl-4-toluene sulfonamide, a resin carrier in dental materials for isolating cavities underneath restorations, and 4-tolyldiethanolamine, an accelerator for inducing polymerization of dental acrylic resins at room temperature. The patient also had allergic patch test reactions to formaldehyde, phenol-formaldehyde resin, fragrance mix, and lauryl monoethanolamide, possibly from occupational exposure.

Excretion of methylhippuric acids in urine of workers exposed to a xylene mixture: comparison among three xylene isomers and toluene

The correlation between exposure to three xylene isomers and resulting urinary excretion of corresponding methylhippuric acid (MHA) isomers was studied among 175 Chinese workers of both sexes who had been predominantly exposed to xylenes (exposure to xylenes accounting for 70% or more of the total exposure on a ppm basis). Nonexposed controls (281 men and women) were also studied to define the background level of MHAs in urine. The solvent exposure of xylene-exposed workers during their workshift was monitored by diffusive sampling of breathing zone air, and MHAs in shift-end urine were determined by high-performance liquid chromatography. Regression analysis showed that the concentration of each MHA isomer correlated significantly with the time-weighted average intensity of exposure to the corresponding xylene isomer, and therefore the correlation between the sum of three xylene isomers in air and that of three MHA isomers in urine was also significant; the slope of the regression line was essentially the same among the three isomers. The calculated regression line suggested that the urinary MHA level after hypothetical exposure to xylenes at 100 ppm will be somewhat less than the proposed biological exposure index and biological tolerance value. Two social habits of smoking and drinking in combination suppressed the conversion of xylenes to MHAs in male workers.

Efficacy of skin barrier creams (I). The repetitive irritation test (RIT) in the guinea pig

An animal model for the evaluation of skin protective creams against chemical irritants is described. The irritants were applied daily for 2 weeks to shaved back skin of young guinea pigs: sodium lauryl sulphate (5% aq.; 30 min), sodium hydroxide (0.5% aq.; 2 min), and toluene (20% eth.; 2 min). The barrier cream was applied 2 h prior to and immediately after exposure to the irritant. Control animals were treated with the irritant only. The irritant reaction was scored on a 4-point scale for erythema and quantified with regard to transepidermal water loss (TEWL) by evaporimetry and skin blood flow volume (BFV) by laser Doppler velocimetry. A total of 90 guinea pigs, consisting of individual panels of 5 to 10 animals, was tested. While one barrier cream (Stokoderm) significantly suppressed the irritation due to sodium lauryl sulphate and toluene, the other (Contra-Alkali) failed to do so and even aggravated the response, which was particularly evident with sodium hydroxide. This model may be useful in developing more effective barrier creams.

Neurobehavioral effects in occupational chemical exposure

Neurobehavioral effects in 30 female workers (aged 18-41, mean 25.6) exposed to an average of 341 mg/m3 (SD 100) toluene for an average of 5.7 years (SD 3.3) compared with 30 matched controls (aged 18-48, mean 25.1), 24 male workers (aged 18-32, mean 24.7) exposed to 268 mg/m3 (SD 185) toluene equivalent of mixed solvent (82.2% toluene, 12.3% ethyl acetate, and 5.5% methyl ethyl ketone) for 2.3 years (SD 3.0) compared with 24 matched controls (aged 17-31, mean 24.3), and 94 dentists (aged 24-49, mean 31.7) exposed to 0.017 mg/m3 (SD 0.009) of elemental mercury for 7.4 years (SD 5.3) compared with 54 referents (aged 23-50, mean 33.6) were studied. The Z score (made up of Digit Span, Symbols Digit, and Grooved Peg Board) for the workers exposed to toluene was 0.79, for workers exposed to mixed solvents was 0.38, and for the dentists exposed to mercury was 0.42. The Z score for each group of exposed subjects was statistically poorer than that for its controls. Neurobehavioral performance was statistically related to exposure intensity for the toluene-exposed workers and to years of exposure or dose (exposure intensity x years of exposure) for mixed solvent- and mercury-exposed subjects. The type of chemical species and pattern of exposure appear to influence whether the adverse effects will be cumulative.

Dose-dependent increase in subjective symptoms among toluene-exposed workers

A factory survey on dose-response relationship in toluene toxicity was conducted in 1985-1989 in four cities in China. The examination items consisted of personal diffusive sampling for TWA exposure measurement, questionnaires on subjective symptoms, hematology and serum biochemistry, and clinical examination including simple neurology tests. Hippuric acid was also determined in urine samples collected at the end of the shift. With selection criteria that (1) complete results were available on all study items and (2) valid toluene exposure data (i.e., toluene shared 90% or more of the exposure) were obtained for the exposed, 452 toluene-exposed workers (206 men and 246 women; toluene exposure at 24.7 ppm as GM) and 517 nonexposed controls (246 men and 271 women) were selected. The subjective symptoms increased in close association with the intensity of exposure to toluene; the threshold concentration appeared to exist at 100 ppm in the case of symptoms during work, and it might be at 50-100 ppm when symptoms off work were evaluated. During the work with exposure at higher concentrations, various symptoms possibly related to CNS or local effects (e.g., eyes, nose, and throat) were complained, and dizziness and floating sensations were identified as typical symptoms with significant dose-response relationship. Several symptoms persisted off work, most of which were apparently related but not necessarily limited to CNS effects. Hematology and serum biochemistry were essentially negative.

A study on the neurobehavioral effects of occupational exposure to organic solvents in Korean workers

In order to investigate the neurobehavioral effects in workers occupationally exposed to organic solvents in Korea using WHO neurobehavioral core test battery (NCTB), a cross-sectional study of 113 male car painters and printers and 81 controls was conducted. Among the seven tests of the NCTB, only four tests--simple reaction time, Santa Ana dexterity, digit symbol, and Benton visual retention tests--were administered to the subjects because of time limitations. Painters and printers were exposed mainly to toluene, xylenes, and methyl ethyl ketone and often to solvent mixtures. The range of the solvent exposure level was 0.10-2.29 of hygienic effect. Poorer performance of Benton visual retention in the exposed group when compared to the control group was found after controlling confounders. No exposure-dependent effect was found. Further investigation with a matched control group regarding confounding factors is required for conclusive results.

Cardiac autonomic dysfunction in rotogravure printers exposed to toluene in relation to peripheral nerve conduction

The autonomic nervous effects of toluene remain less clear. To clarify this neurotoxicity, ten rotogravure printers and the same number of age-matched unexposed controls were examined, by using the coefficient of variation in electrocardiographic R-R intervals (CVRR), the distribution of nerve conduction velocities (DCV) and the maximal motor and sensory nerve conduction velocities (MCV and SCV) in the median nerve. Also, the C-CVHF and C-CVLF (two component CVs of the CVRR reflecting parasympathetic and sympathetic activities, respectively) were computed from component spectral powers using autoregressive spectral and component analyses. These printers had been exposed to toluene (estimated exposure levels of toluene at 83 ppm) for 1-36 years. The CVRR and C-CVHF were significantly lower in the printers than in the controls. No significant difference between the printers and the controls was found in either any DCV parameters or the SCV in the forearm, except the MCV and the SCV in the palm. In the light of previous work on the brainstem/hippocampus damages due to toluene, these data suggest that toluene causes potential damages in the central autonomic nervous system, mainly parasympathetic hypoactivity.

Neurotoxicity induced by exposure to toluene. An electrophysiologic study

The object of the present study was to evaluate, with the aid of electrophysiologic techniques, the alterations induced in the auditory nervous system by exposure to toluene in a group of rotogravure workers. From 300 workers who were apparently in good health but were professionally exposed to toluene, we selected a sample of 40 workers of normal hearing ability. They were examined with an adaptation test studied by the brainstem auditory evoked potential technique with 11 and 90 stimulus repetitions a second. The results were compared with those in a group of workers of the same age but not professionally exposed to solvents. Our study demonstrates that exposure to toluene is able to induce a statistically significant alteration in the electric responses with both 11 and 90 stimuli repetitions. This alteration can be explained as a toluene exposure-induced modification, of physiologic stimulus conduction mechanisms, even in the absence of any clinical sign of neuropathy. Furthermore, such a modification could be observed in the electric responses of the entire auditory system, from peripheral receptors to brainstem nuclei.

Menstrual function in workers exposed to toluene

Rates of menstrual disorders were studied in 231 female production workers with high exposure to toluene (mean 88 (range 50-150 ppm) in a factory manufacturing audio speakers and compared with a control group of 58 female production workers in other departments in the same factory who had little or no exposure to toluene (0-25 ppm). An external community control group of 187 working class women under routine care at public maternal and child health centres were also studied. Detailed menstrual and reproductive histories were obtained by personal interview using a structured questionnaire. The rates for dysfunctional uterine bleeding (cycle irregularity and prolonged or heavy menstrual bleeding) were similar in all groups. Dysmenorrhoea seemed to occur more often in the women highly exposed to toluene compared with women at maternal and child health centres, but not compared with factory controls with low exposure to toluene. There was no evidence that dysfunctional uterine bleeding was likely to result from exposure to toluene. It is uncertain whether dysmenorrhoea was associated specifically with exposure to toluene, as other behavioural and work related factors may also result in dysmenorrhoea.