Acetonitrile is a high-polarity organic solvent widely used in various chemical industries and laboratories. It was once used in consumer goods such as cosmetics. Acetonitrile is readily absorbed through the skin, by inhalation and by ingestion, and acute poisoning and even fatal effects are possible via these routes. The oral LD₅₀ of acetonitrile in mice, which are one of the most susceptible animals to acetonitrile, is 170-520mg/kg, and LC₅₀ is about 2, 700ppm after one hour of inhalation. The toxic effects of acetonitrile are attributable to the metabolic release of cyanide, but the symptoms of poisoning may be delayed a few hours or more due to slow hepatic metabolism. No information is available yet about the toxicity of intact molecules of acetonitrile or formaldehyde which may be formed together with cyanide in the body. In subacute toxicity experiments in animals, slight changes in hemograms, histopathologic changes in the lung, increase in thyroid function, and other changes have been reported. No information is available about the accumulation of acetonitrile or its metabolites in tissues following repeated administrations, although formaldehyde is known to have high reactivity with macromolecules. No study has yet been done on the chronic toxicity or carcinogenicity of acetonitrile after prolonged administration. Acetonitrile is not mutagenic in the standard test using Salmonella typhimurium. Inhalation of acetonitrile by pregnant animals may produce malformations in the offspring such as axial skeletal disorders at maternally toxic levels. Education and information about the toxicity and regulations on the marketing of acetonitrile are of great importance for the safe use of this material. Further studies and information are needed on the chronic effects of acetonitrile, especially its carcinogenic potency, to human beings.

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To evaluate physical and mental workload in middle-aged workers, urinary excretion of catecholamines and cortisol and self-reported scores of fatigue, stress and arousal in middle-aged steel workers were compared with those in young steel workers. Noradrenaline excretion in daytime of the day-off was higher in middle-aged workers than that in young workers. In the work days, noradrenaline excretion during working hours increased in both age groups when compared with that in the day-off. The work-related increase in noradrenaline excretion was more evident in the middle-aged group than in the young group. Adrenaline excretion during working hours was greater in the middle-aged group than that in the young group, whereas the adrenaline value in the day-off was almost the same in the two age-groups. Age-difference was hardly observed in dopamine and cortisol excretion. These findings suggest that the workload in middle-aged workers was greater than that in young workers.
However, self-reported scores of fatigue and stress in middle-aged workers were less than those in young workers, suggesting inconsistency between subjective scores of workload and urinary levels of catecholamines.
These age-related differences in urinary levels of noradrenaline and adrenaline were not so obvious in workers engaged in automated and mechanized work (vigilance task) when compared to workers engaged in less automated and less mechanized work. It is considered that factory automation might reduce the workload in middle-aged workers.

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It was confirmed that the function of DMSO as an inducer of cell differentiation was suppressed by co-culture of crocidolite asbestos, using the activity of protein kinase C as indicator, because DMSO reacted with ·OH radical released by stimulation with crocidolite and wasted itself. SOD inhibited the effect of crocidolite, because SOD reacted with ·O₂- released by stimulation with crocidolite and inhibited the subsequent development of ·OH.

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Exposure of workers to electric and magnetic fields from radiofrequency dielectric heaters (RF heaters) to process polyvinyl chloride material was surveyed. Measurements of electric and magnetic field strengths were made in 10 workers operating 7 RF heaters at 3 plants in Japan. Six of the RF heaters are of the sewing machine type and the other is of the shuttle tray type. In all the RF heaters surveyed the nominal frequency of the radiofrequency generator was 40 MHz, and therefore electric and magnetic field from these are assumed to oscillate at the same frequency. The power output ranged from 0.83 W to 1.8 W for the sewing machine type and was 2.4 W for this shuttle tray type. Measurements were made at about 5 cm from the surface of the hand, eye, chest, waist, knee and foot of each worker. The meter readings were converted to equivalent plane wave power density and corrected for duty cycle (0.073 to 0.27).
It was found that all the workers surveyed were exposed to electric and magnetic field strengths greater than the TLV recommended by ACGIH (1 mW/cm²). For the hand, eye, chest, waist, knee and foot of the worker, 95%, 63%, 32%, 47%, 36% and 27% of the measured field strengths exceeded the TLV, respectively. Especially for the sewing machine type RF heaters, electric fields at the hand and eye were extremely strong. Thus, for the hand, 100%, 75% and 38% of the measured electric field strengths exceeded the TLV, ten times the TLV, and one hundred times the TLV, respectively, and for the eye, 88% and 25% exceeded the TLV and ten times the TLV, respectively. No correlation was observed between power output of the RF heaters and measured electric and magnetic field strengths at any anatomical site of the worker.

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In order to clarify urinary metabolites of p-chloroaniline (p-CA), urine samples of a patient acutely poisoned with p-CA were analyzed by gas chromatography/mass spectrometry.
Urinary metabolites were extracted with diethylether at pH 1.0 and pH 10 from urine samples hydrolyzed with acid and base and from intact urine samples. Aliquots of the ethereal extracts were injected into the gas chromatograph, and p-CA and its metabolites were identified by comparing their mass spectra and retention times to those of standards.
Six substances identified were as follows: p-CA, 2-amino-5-chlorophenol, 2, 4-dichloroaniline, p-chloroformanilide and traces of p-chloroacetanilide and 4-chloro-2-hydroxyacetanilide.
Since p-CA was mainly detected in the hydrolyzed urine samples, p-CA was considered to form conjugates in the urine. N-Acetylation reactions of p-CA were suggested to be weak in human, because extremely minute amounts of p-chloroacetanilide and 4-chloro-2-hydroxyacetanilide were detected in the urine.

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To assess the contact allergic potential of sensitizers, an in vitro predictive model was developed. First of all, guinea pigs were sensitized by 1-chloro-2-4-dinitrobenzene (DNCB), and lymph node cells from sensitized and control guinea pigs were cultured in the presence of DNCB, 2, 4-dinitrobenzene sulfonic acid sodium salt (DNBS), DNCB plus epidermal cell (DNCB+EC), DNBS+EC and epidermal cell modified hapten (dinitrophenyl-EC, DNP-EC) at 3×10⁵, 5×10⁵ and 8×10⁵ cells/well, respectively. Lymphocyte blastogenesis responses were assessed by uptake of ³H-thymidine.
The results indicated that lymphocytes from sensitized guinea pigs responded to the foregoing antigens in vitro to a greater degree than those from control guinea pigs and the blastogenesis response by DNBS was the highest among the challenges of DNBS, DNCB, DNCB+EC, DNBS+EC and DNP-EC. When the number of lymphocytes was sufficient, the blastogenesis response of lymphocytes could be in vitro challenged successfully not only by DNBS, DNCB+EC, DNBS+EC and DNP-EC, but also DNCB alone. There was a cross sensitivity between DNCB and DNBS for in vivo and in vitro challenges. Moreover, significant relationships were observed between lymphocyte blastogenesis response and doses of DNBS used in vitro assay at 5×10⁵ and 8×10⁵ cells/well.
The results indicate that this assay is an useful in vitro predictive model of contact sensitivity and cross sensitivity of sensitizers.

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A yearly ophthalmological examination was carried out in 2 VDT worker groups (A-1 and B-1 groups) and 2 control groups (A-2 and B-2 groups). The 4 groups were as follows; workers routinely engaged in both VDT work and key-punch work at a printing company (A-1 group), researchers or office workers handling VDT irregularly at a chemical company (B-1 group), typesetters at a printing company (A-2 group), and office workers at a chemical company (B-2 group). The examination was commenced in the same year in which the workers of A-1 or B-1 group were introduced to VDT work and was carried out for 3 years.
Comparison between the first and the last examination on subjective refactive power showed that all the groups had lower refractive powers in the last examination than the first one. The workers of A-1 group showed the greatest decrease in refractive power among the 4 groups. The decrease in A-2 group was more severe than in the other 2 groups.
Before VDT introduction, the workers of A-1 group had been engaged only in key-punch work. Information on naked visual acuities of A-1 group 3 years before VDT introduction was also obtained and compared with those in the first and the last examination. The ratio of workers with a severe reduction in visual acuity evidently increased after VDT introduction.
In the first examination, accommodative powers of workers at the printing company were lower than those of workers at the chemical company irrespective of VDT work, and most ophthalmological subjective symptoms were observed in workers of A-1 group. However, no changes in accommodative power or in the number of the subjective symptoms were observed between the first and the last examination in the all groups.
These results indicate that 1) VDT work may be associated with the decline in visual acuity among workers of A-1 group; 2) key-punch or typesetting work at the printing company involved more visual burden than irregular VDT work in the chemical company; and 3) engagement in work of visual nature other than VDT work is an important factor in the establishment of guidelines for VDT work.

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Subjective symptoms and blood findings were studied in 16 construction workers and 30 vehicle repairmen using organic solvent and compared to 30 workers who were not exposed to organic solvents.
A statistically significant increase was observed in the prevalence of subjective symptoms, serum phospholipid, lipoprotein fraction and IgE level in construction workers and vehicle repairmen.
A statistically significant decrease in neutrophils function was observed in construction workers.

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