Occupational dimethylformamide exposure. 1. Diffusive sampling of dimethylformamide vapor for determination of time-weighted average concentration in air

A diffusive sampling method with water as absorbent was examined in comparison with 3 conventional methods of diffusive sampling with carbon cloth as absorbent, pumping through National Institute of Occupational Safety and Health (NIOSH) charcoal tubes, and pumping through NIOSH silica gel tubes to measure time-weighted average concentration of dimethylformamide (DMF). DMF vapors of constant concentrations at 3-110 ppm were generated by bubbling air at constant velocities through liquid DMF followed by dilution with fresh air. Both types of diffusive samplers could either absorb or adsorb DMF in proportion to time (0.25-8 h) and concentration (3-58 ppm), except that the DMF adsorbed was below the measurable amount when carbon cloth samplers were exposed at 3 ppm for less than 1 h. When both diffusive samplers were loaded with DMF and kept in fresh air, the DMF in water samplers stayed unchanged for at least for 12 h. The DMF in carbon cloth samplers showed a decay with a half-time of 14.3 h. When the carbon cloth was taken out immediately after termination of DMF exposure, wrapped in aluminum foil, and kept refrigerated, however, there was no measurable decrease in DMF for at least 3 weeks. When the air was drawn at 0.2 l/min, a breakthrough of the silica gel tube took place at about 4,000 ppm.min (as the lower 95% confidence limit), whereas charcoal tubes could tolerate even heavier exposures, suggesting that both tubes are fit to measure the 8-h time-weighted average of DMF at 10 ppm.

Genotoxicity of beryllium, gallium and antimony in short-term assays

The genotoxicity of beryllium, gallium and antimony compounds was studied with the rec, Salmonella mutagenicity and SCE assays. In the rec assay, all the salts of the metals, BeCl2, Be(NO3)2, GaCl3, Ga(NO3)3, SbCl3, SbCl5, and an oxide, Sb2O3, had DNA-damaging activity. None of the compounds was mutagenic to Salmonella. In the SCE assays using V79 cells, 2 antimony(III) compounds, SbCl3 and Sb2O3, and 2 beryllium compounds, BeCl2 and Be(NO3)2, induced SCEs significantly. Sb2O3, slightly soluble in water, was positive in both the rec assay and the SCE assay at very low doses.

A questionnaire study on fatigue symptoms of municipal personnel

The following questionnaire surveys were conducted on 390 male personnel who work in one of the public facilities of a certain city. 1) Fatigue surveys: Using the Fatigue Scale of Industrial Fatigue Research Committee, questionnaire investigations were carried out twice, before work and after work. 2) Health surveys: Using Cornell Medical Index, the neurotic tendency was examined. When the correlation factors of average complaints frequencies were analyzed, indoor workers showed a type of mental task before and after work, whereas outdoor workers showed a type of mental task before work, but showed a general type after work. The workers in generation below thirty-five years mainly showed a type of mental task, while complaints about physical disintegration were relatively frequent in generation above fifties. We consider such questionnaire researches at each work site will constitute a useful clue for examining and ameliorating workers' fatigued condition which may exist inordinately in daily duties.

Erythrocyte deformability in workers exposed to lead

Erythrocyte deformability and other hematological indicators were determined in 17 male workers exposed to lead at a secondary lead refinery and 13 controls. Blood lead, urine lead, urine coproporphyrin, delta-aminolevulinic acid and erythrocyte zinc protoporphyrin were determined to evaluate the degree of lead exposure in the lead workers above. For the measurement of erythrocyte deformability, the microfilter method was used. The results were summarized as follows: 1. The mean values of blood lead, urine lead, urine coproporphyrin, urine delta-aminolevulinic acid and erythrocyte zinc protoporphyrin levels in lead workers were 53.5 micrograms/100g, 141.4 micrograms/l, 115.9 micrograms/l, 12.0 mg/l and 68.9 micrograms/dl respectively, suggesting a moderate influence of lead exposure. 2. The mean values of erythrocyte count, hematocrit and hemoglobin were significantly lower in lead workers than those in controls. No significant differences were found in the mean values of mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and corpuscular natrium and potassium between lead workers and controls. 3. Erythrocyte deformability was significantly reduced in lead workers compared with controls.

Methanol in urine as a biological indicator of occupational exposure to methanol vapor

The exposure-excretion relationship and possible health effects of exposure to methanol vapor were studied in 33 exposed workers during the second half of 2 working weeks. Urinary methanol concentrations were also determined in 91 nonexposed subjects. The geometric mean value for methanol in urine samples from the latter was less than 2 mg/l (95% upper limit of normal, less than 5 mg/l) when log-normal distribution was assumed. Among the exposed workers, the methanol level in urine samples collected prior to the work shift exceeded the 95% upper limit of normal. The time-weighted average intensity of exposure to methanol vapor was measured using personal sampling devices (in which water severed as an absorbent) in 48 cases of methanol exposure (i.e., 2 of the 33 exposed workers failed to provide urine samples, whereas 17 subjects were examined twice). Methanol concentrations in urine were determined in samples collected at the end of the shift from the 48 exposed cases as well as from 30 nonexposed controls. There was a significant correlation between the exposure to methanol vapor at concentrations of up to 5,500 ppm and the levels of methanol measured in the shift-end urine samples. The calculation indicated that a mean level of 42 mg methanol/l urine (95% confidence range, 26-60 mg/kg) was excreted in the shift-end urine sample following 8 h exposure to methanol at 200 ppm (the current occupational exposure limit). Dimmed vision and nasal irritation were among the most frequent symptoms complained during work. Three cases showing clinical signs of borderline significance were identified.

Dose-dependent increase in 2,5-hexanedione in the urine of workers exposed to n-hexane

The concentrations of 2,5-hexanedione (2,5-HD), an n-hexane metabolite, and 2-acetylfuran (2-AF) were measured in urine samples from 123 workers who had predominantly been exposed to n-hexane vapor and 53 workers who had experienced no exposure to solvents. The time-weighted average intensity of exposure to n-hexane vapor was determined by a diffusive sampling method. For biological monitoring of exposure, urine samples were collected late in the afternoon during the second half of a working week and were analyzed in the presence and absence of acid hydrolysis (at pH less than 0.5) for 2,5-HD and 2-AF by gas chromatography on a nonpolar capillary DB-1 column. The urinary 2,5-HD concentration increased as a linear function of the intensity of exposure to n-hexane, showing a correlation coefficient of 0.64-0.77 after acid hydrolysis and that of 0.73-0.83 in the absence of hydrolysis, depending on the correction for urinary density (P less than 0.01 in all cases, with no improvement in the coefficient occurring after the corrections). In contrast, 2-AF levels were independent of n-hexane exposure. The geometric mean 2,5-HD concentration in urine samples from 53 nonexposed men was 0.26 mg/l as observed (i.e., with no correction), 0.19 mg/l after correction for a urinary specific gravity of 1.016, and 0.23 mg/g creatinine after correction for creatinine concentration, and the geometric standard deviation was approximately 2.

2-Acetylfuran, a confounder in urinalysis for 2,5-hexanedione as an n-hexane exposure indicator

The apparent amount of 2,5-hexanedione, a biomarker of n-hexane expsoure in occupational health, in the urine of both exposed and non-exposed subjects varied not only as a function of the pH at which the urine sample was hydrolyzed but also depending on the capillary column used for gas chromatographic (GC) analysis of the urinary hydrolyzates after extraction with dichloromethane. The formation of a compound, identified by gas chromatography-mass spectrometry (GC-MS) as 2-acetylfuran, following acid hydrolysis was a major cause of confounding effects. This compound was hardly separated from 2.5-hexanedione on a capillary column such as DB-WAX, whereas separation could be achieved on a DB-1 capillary column. 2-Acetylfuran was formed when a urine sample was heated at a pH of less than 2 for hydrolysis, and the amount detected in urine did not differ between exposed and non-exposed subjects, indicating that the formation of 2-acetylfuran is independent of n-hexane exposure. When urinary hydrolysis is used, hydrolysis at a pH of less than 0.5, extraction with dichloromethane, and GC analysis on a non-polar capillary column are proposed to be the best analytical conditions for 2,5-hexanedione analysis in biological monitoring of exposure to n-hexane.

A case of lead poisoning recovered by transposition of the work post

A case of lead poisoning in a secondary lead refinery was reported. A 58 year old man working at the post of lead refining complained of severe lassitude and diarrhea. By increased urine coproporphyrin excretion, he was suspected of a case of lead poisoning. Clinical data from the health examinations revealed that he had been affected by lead. The patient was transposed to another work post where lead was not handled and rapidly recovered from the poisoning.

Urinary methylhippuric acid isomer levels after occupational exposure to a xylene mixture

The quantitative relationship between exposure to xylene vapor and urinary excretion of methylhippuric acid (MHA) isomers were studied in the second half of a working week. The participants in the study were 121 male workers engaged in dip-coating of metal parts who were predominantly exposed to three xylene isomers. The intensity of exposure measured by diffusive sampling during an 8-h shift was such that the geometric mean vapor concentration was 3.8 ppm for xylenes (0.8 ppm for o-xylene, 2.1 ppm for m-xylene, and 0.9 ppm for p-xylene), 0.8 ppm for toluene, and 0.9 ppm for ethylbenzene. Urine samples were collected at the end of the shift and analyzed for metabolities by HPLC. The statistical analysis showed that there is a linear relationship between the intensity of exposure to xylenes and the concentration of MHA in urine, that the regression line passes very close to the origin, and that the increment in observed (i.e., noncorrected) MHA concentrations as a function of increasing xylene concentration was 17.8 mg x l-1 ppm-1. Further examination on the basis on individual xylene isomers showed that the slopes of the regression lines for o- and m-isomers were similar (i.e., 17.1 and 16.6 mg l-1 ppm-1, respectively), whereas that for p-xylene was larger (21.3 mg l-1 ppm-1).

If the fetus can vocalize, how can we detect it?

In this paper, a method to detect the vocal activities of the fetus is reported. An estimation of the intensity and frequency of the voice was made on the assumption that the fetus can vocalize. Based upon these results, experiments to detect the voice were made. From the analysis of the results, it was made clear that the voice seemed to be buried in the noise and difficult to detect.

A consideration of salt intake from foods based on the simultaneous measurement of sodium and chlorine by neutron activation analysis

Ordinary hospital meals for adults were simultaneously measured for Na and Cl by neutron activation analysis (NAA). Results obtained are summarized as follows: 1. Daily Na intake was estimated to be 4 to 8 g, corresponding to 11 to 18 g of salt. Daily Cl intake was estimated to be 5 to 9 g, corresponding to 7 to 12 g of salt. Their ratio was 1.6. 2. The higher values of salt intake obtained by conversion from Na intake are attributable to food additives. 3. In rating Na content, which has been reported to affect blood pressure, on the basis of salt intake, attention must be given to the fact that salt content converted from Cl content is rated to be lower than that converted from Na content.

Biological monitoring of occupational exposure to isopropyl alcohol vapor by urinalysis for acetone

The relationship of the intensity of occupational vapor exposure to isopropyl alcohol (IPA) with urinary excretion of acetone and unmetabolized IPA was studied in 99 printers of both sexes, who were exposed to up to 66 ppm IPA (as time-weighted average), together with toluene, xylenes, methyl ethyl ketone and/or ethyl acetate. Acetone and IPA concentrations in urine were studied also in 34 non-exposed subjects. Acetone was detectable in the urine of most of the non-exposed, and the urinary acetone concentration increased in proportion to the IPA exposure intensity (r = 0.84 for observed, non-corrected values), whereas the correction for creatinine concentration or specific gravity of urine did not give a larger correlation coefficient. IPA itself was not found in the urine of the non-exposed, and was detectable in urine of only those who were exposed to IPA above a certain level, e.g. 5 ppm. The present study results suggest that urinary acetone is a valuable index for biological monitoring of occupational exposure to IPA as low as 70 ppm.

Urinary N-acetyl-beta-D-glucosaminidase activity in lead-exposed workers

The adverse effects of long-term exposure to lead dust on renal tubular functions were studied in 39 male and 7 female workers in a secondary lead refinery. Laboratory examinations showed low or moderate lead absorption levels. The N-acetyl-beta-D-glucosaminidase (NAG) activity in urine showed significant correlation with each of the lead exposure indices. NAG activity increased remarkably in lead workers with blood lead (PbB) above 80 micrograms 100g-1. Blood urea nitrogen (BUN) showed significant correlation with PbB and logarithmic urine delta-amino-levulinic acid (log(ALAU)), but not with urine lead (PbU) and logarithmic urine coproporphyrin (log(CPU)). All the other indices of renal function were almost within the normal range and showed no correlation with lead indices. This study suggests that moderate lead absorption may cause renal tubular impairment, and NAG can be one of the most sensitive indices for estimating renal dysfunction due to lead poisoning.

Neutron activation analysis of manganese contents in ordinary hospital meals

Neutron activation analysis (NAA) was applied to measurement of manganese (Mn) content in food as an example of ordinary hospital meals. The results showed that: 1. NAA permits measurement of Mn with a simple pretreatment procedure in comparison with AAS (atomic absorption analysis). 2. Daily Mn intake was estimated to be about 3 mg from food, and about 4 mg from green tea. Neutron activation analysis (NAA) has been used for measuring various elements under the conditions appropriate for the irradiated or radioactivated subject of analysis. We presently applied NAA to measurement of manganese (Mn) contents in food as an example of ordinary hospital meals with an estimation of daily Mn intake.

Epidemiological study of mortality from cancer among chromium platers

Cancer mortality was studied among 265 male workers in 40 small plating factories (chromium, copper and nickel) where bicycle parts are plated. The study utilized record linkage with the Osaka Cancer Registry file between January 1, 1965 and December 31, 1979. The results showed that seven workers had died of cancer, and the Standardized Mortality Ratio (SMR) calculated for all cancers, stomach cancer and lung cancer were 1.13, 1.23 and 1.11, respectively, with no significant relationship found between the observed and expected values. The SMR for lung cancer among those workers with a high degree of skin ulceration and with perforation of the nasal septum was high, 11.22 and 5.13, respectively, although not statistically significant because of the small sample size in the study. The results suggest that lung cancer occurs in those subjected to a high degree of exposure to chromium.

Nociceptive effects induced by intrathecal administration of prostaglandin D2, E2, or F2 alpha to conscious mice

The effects of intrathecal administration of prostaglandins on pain responses in conscious mice were evaluated by using hot plate and acetic acid writhing tests. Prostaglandin D2 (0.5-3 ng/mouse) had a hyperalgesic action on the response to a hot plate during a 3-60 min period after injection. Prostaglandin E2 showed a hyperalgesic effect at doses of 1 pg to 10 ng/mouse, but the effect lasted shorter (3-30 min) than that of prostaglandin D2. Similar results were obtained by acetic acid writhing tests. The hyperalgesic effect of prostaglandin D2 was blocked by simultaneous injection of a substance P antagonist (greater than or equal to 100 ng) but not by AH6809, a prostanoid EP1-receptor antagonist. Conversely, prostaglandin E2-induced hyperalgesia was blocked by AH6809 (greater than or equal to 500 ng) but not by the substance P antagonist. Prostaglandin F2 alpha had little effect on pain responses. These results demonstrate that both prostaglandin D2 and prostaglandin E2 exert hyperalgesia in the spinal cord, but in different ways.

Measurement of erythrocyte arginase activity and the effect of lead on the activity in vitro

Measurement of arginase activity made by varying the arginine concentration and the reaction time clarified that the amount of urea formed by arginase peaked at the substrate concentration of 150 mmol/l, and increased linearly by 20 minutes. By using discs punched out from a dried blood filter paper prepared from identical human blood sample, the amount of formed urea showed linear increase up to 160 U/g.Hb. The coefficients of variation in ten measurements were 6.1% for the mean activity of 46.2 U/g.Hb and 2.1% for 152.1 U/g.Hb. No decreases in arginase activity were observed when two different dried blood filter papers were left for one week at room temperature. Intact erythrocytes were treated with various concentrations of lead from 0 to 5 mumols/l and their arginase activities were measured. The activity did not elevate linearly with the rise of lead concentration, but an almost diphasic elevation was observed. The arginase activity of erythrocytes treated with 5 mumols/l of lead was higher than that for untreated ones by 32%.

Effects of styrene on wheel-running and ambulatory activities in mice

Effects of styrene on wheel-running and ambulatory activities were investigated in mice. Sixty male mice (ICR strain) were divided into 10 groups of six mice each, and they were exposed to styrene of about 930, 425, 60, 25 or 0 ppm (control group) for 4 hours a day, 5 days a week over 2 weeks. The wheel-running and ambulatory activity tests were conducted during 2 weeks of the styrene exposure, and 1 week before and after the exposure. The wheel-running activity decreased at the high concentrations (930 and 425 ppm), and the decreased activity did not recover to the control level after cessation of the exposure. In the ambulatory activity test, styrene exposure resulted in the decrease in the activity, though the change was not concentration-dependent. The present results suggest that the behavioral effect of styrene is clearly detectable by means of wheel-running and ambulatory activities in mice.

Cloning and expression in Escherichia coli of the gene for mouse tumor necrosis factor

The mouse tumor necrosis factor (TNF) gene was isolated from a mouse genomic library. The entire sequence of the gene was determined using both an automated DNA sequencer with improved primer extension reaction conditions as well as the standard radioisotopic method. Comparison of the nucleotide sequence of the gene with that of mouse TNF cDNA showed that the mouse gene consists of four exons, like rabbit and human TNF genes. There is strong nucleotide sequence homology in the 5'-flanking region among the mouse, rabbit, and human TNF genes, suggesting that the mechanisms regulating TNF gene expression are highly conserved. Direct expression of mature mouse TNF was achieved using a plasmid constructed by site-directed mutagenesis. Purified mouse TNF produced in Escherichia coli showed cytotoxicity to mouse L cells.