Cost-Effectiveness Analysis of the Diagnosis and Treatment of Primary Aldosteronism in Japan

Approximately 10% of cases of hypertension in Japan are caused by primary aldosteronism (PA), amounting to about 4 million patients in total. Primary aldosteronism due to unilateral aldosterone hypersecretion is potentially curable by adrenalectomy. The clinical benefits of identifying and treating PA have been reported internationally, but its cost-effectiveness is unclear. We examined whether diagnosing and treating hidden PA in hypertensive population was cost-effective compared with suboptimal treatment. Our hypothetical patient was a 50-year-old man diagnosed with stage I-III hypertension. We established a Markov decision model based on plausible clinical pathways and prognoses of PA. We applied cost-effectiveness analysis comparing a comprehensive diagnostic strategy for PA (measurement of plasma aldosterone/renin ratio, 2 loading tests, imaging, and selective adrenal venous sampling) with a suboptimal strategy to manage hypertension by medication unless the typical signs of PA or other complication were manifest. Outcome measures were expected costs, expected effectiveness, and incremental cost-effectiveness ratio. The robustness of the findings was established by one-way and scenario sensitivity analyses. The comprehensive PA diagnostic strategy increased the expected costs by 64 004 JPY and expected life-years by 0.013 compared with standard treatment. The incremental cost-effectiveness ratio for the diagnosis of PA was 4 923 385 JPY per year. Our findings were sensitive to the outcomes of screening and treatment, and the costs of continuous or periodic medication for hypertension and the treatment of stroke and its complications.

Upper-extremity Musculoskeletal Disorders in Keyboard Operators in Brazil: A Cross-sectional Study

This study sought to determine the prevalence of upper-extremity musculoskeletal disorders (UEMSDs) among keyboard operators in Sao Paulo, Brazil, and to compare this prevalence with that among other office workers. One hundred and thirty keyboard operators (mean age 33 years, 60 male/70 female) and 138 office workers (mean age 35 years, 82 male/56 female) from two computing centers were interviewed by a research assistant using a standardized questionnaire. Symptomatic subjects, defined as those who reported upper extremity pain or lost work time due to pain in the preceding 12 months, were examined by a rheumatologist. Mean (SD) lengths of employment were 9 (6) years for keyboard operators and 8 (6) years for office workers. Upper-extremity pain during the preceding seven days was reported by 66 keyboard operators (51%) and by 18 office workers (13%) (p < 0.0001); during the preceding 12 months, by 90 keyboard operators (69%) and by 26 office workers (19%) (p < 0.0001). UEMSDs were diagnosed following physical examination in 50 keyboard operators and in 12 office workers (9%) (p < 0.0001). Tenosynovitis was the most common disorder diagnosed among the keyboard operators (n = 23). Among the keyboard operators the prevalence of UEMSDs was significantly lower for males (p = 0.017, OR = 0.38, 95%CI = 0.17-0.86). The presence of a diagnosed UEMSD was significantly associated with duration of employment (p = 0.005) and lack of or insufficient rest breaks (p = 0.012). Keyboard operators had significantly more UEMSDs than did office workers. Strategies aimed at the reduction of repetitive strain injuries among keyboard operators, such as the provision of adequate work breaks, should be evaluated.

Subtle increase in leukocyte counts in association with drinking and smoking habits

Peripheral leukocyte counts were examined in venous blood of more than 800 male workers exposed to toluene, xylenes, a combination of the two, or neither. Information on the social habits of smoking and drinking was obtained in an occupational health interview. The analysis showed that smoking (15 cigarettes/day on average) induced a significant increase (by 7%) in leukocyte counts, and that an additional increase was induced when the drinking habit was coupled with smoking. Drinking alone tended to increase the leukocyte counts but the effect was statistically nonsignificant, possibly because the number of nondrinking smokers was limited. The study stresses the importance of paying attention to smoking and drinking habits when evaluating hematological parameters such as peripheral leukocyte counts in solvent-exposed workers.

Urinary Phenylglyoxylic Acid Excretion after Exposure to Ethylbenzene among Solvent-exposed Chinese Workers

Factory surveys were conducted in the second half of work weeks on 360 solvent workers (202 men and 158 women) and 281 controls in China. Monitoring personal exposures showed that ethylbenzene exposure was low (geometric mean 1.8 ppm) and was accompanied by coexposure to toluene (1.5 ppm) and three xylene isomers (6.7 ppm). Urine samples collected at the end of the eight-hour shift were analyzed for phenylglyoxylic and mandelic acids by high-pressure liquid chromatography at 257 nm. Despite the low level of the exposures, a significant correlation was observed between ethylbenzene exposure and urinary phenylglyoxylic acid, with high (0.6-0.7) correlation coefficients, suggesting that urinary phenylglyoxylic acid is a good marker of occupational exposure to ethylbenzene. Mandelic acid also correlated with ethylbenzene exposure, but with much smaller coefficients (0.2), possibly because the method employed was more sensitive to phenylglyoxylic acid than to mandelic acid.

Effects of smoking and drinking habits on urinary o-cresol excretion after occupational exposure to toluene vapor among Chinese workers

The relationship between the time-weighted average intensity of exposure to toluene and o-cresol concentration in shift-end urine was investigated in nearly 500 factory workers of both sexes in China, together with a similar number of nonexposed control subjects. Toluene concentration (25 ppm as geometric mean and 550 ppm as the maximum) was monitored by diffusive sampling using carbon cloth as adsorbent followed by gas chromatographic (GC) analysis. o-Cresol (up to 7 mg/l) was measured by GC after acid hydrolysis of samples. Urinary o-cresol levels correlated significantly (r = 0.69-0.77; p < 0.01) with toluene exposure in men, women and the two sexes in combination, regardless of correction for urine density. When compared with hippuric acid, however, o-cresol was less sensitive as an indicator of exposure to toluene and is not a suitable biological marker for detecting low level toluene exposure. Since urinary o-cresol level was significantly reduced by smoking, drinking, and the two habits combined, it cannot be considered reliable as an indicator of exposure to toluene.

Exposure monitoring and health effect studies of workers occupationally exposed to cyclohexane vapor

A survey was conducted in the second half of a working week on 33 women who either applied glue (with cyclohexane as an almost exclusive solvent component) or worked in the vicinity of glue application. Carbon cloth-equipped diffusive samplers were used for personal measurement of time-weighted average intensity of exposure to the solvent. The geometric mean and the highest cyclohexane concentration observed in air were 27 ppm and 274 ppm, respectively. Concentrations of cyclohexanol in urine samples and cyclohexane in whole blood and serum collected at the end of a shift showed significant correlations with the solvent exposure levels. Urinary cyclohexanone also correlated, but with a smaller correlation coefficient. The observation suggests that cyclohexanol in urine and cyclohexane in blood or serum collected at the end of a shift are useful indicators of occupational exposure to cyclohexane vapor. Quantitative estimation of balance at the end of the shift suggested that only a minute portion (< 1%) of cyclohexane absorbed is excreted in the urine as cyclohexanol, almost exclusively as a glucuronide. A survey of subjective symptoms revealed an increase in the prevalence of "dimmed vision " and "unusual smell", but hematology and serum biochemistry testing did not indicate any specific signs.

Absence of mutagenicity in peripheral lymphocytes of workers occupationally exposed to methyl methacrylate

Chromosome aberration rates and sister chromatid exchange frequency were examined in the peripheral lymphocytes of 38 male workers who were engaged in organic glass production and exposed to methyl methacrylate (MMA) vapors at the concentrations of 0.9 ppm to 71.9 ppm. The results were compared with the findings in the concurrent nonexposed male subjects. Comparison of the exposed group with the nonexposed controls showed that there were no exposure-related changes in chromosome aberration rate. SCE frequency was higher in the exposed group than in the controls, but this was considered to be due to higher ages of the former group than that of the latter. In fact, selection of nonsmokers and further classification of the exposed nonsmokers into two groups of those with exposure below and above a median MMA concentration (ca. 4 ppm) failed to show any difference among the three nonsmoking groups in cytogenetic parameters, or any dose-dependency. The present results, although in a limited number of subjects, indicate that occupational methyl methacrylate exposure under the conditions studied is not associated with mutagenicity. This conclusion confirms the absence of mutagenicity of methyl methacrylate in humans, and is in general agreement with a majority of the results of studies on mutagenicity in vitro, animal carcinogenicity and occupational cancer epidemiology of methyl methacrylate.

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.

Effects of smoking and drinking on excretion of hippuric acid among toluene-exposed workers

In order to investigate possible effects of smoking and drinking on the metabolism of toluene in occupational settings, 206 toluene-exposed men (mean age: 31.4 years) in shoemaking, painting, or surface-coating workshops together with 246 nonexposed control men (36.8 years) were studied for the time-weighted average intensities of exposure to toluene, hippuric acid concentration in shift-end urine samples, and the two social habits of smoking and drinking. The mean daily consumptions of cigarettes and ethanol were about 20 pieces and 10 g among smokers and drinkers, respectively. The geometric mean toluene concentration among the exposed subjects was about 20 ppm, with a maximum of 521 ppm. Regression analysis after classification of the subjects by smoking and drinking clearly demonstrated that the two social habits, when combined, markedly reduce the hippuric acid level in the urine of workers exposed to toluene. There was a significant association between smoking and drinking habits, which hindered separate evaluation of the effects of the two habits on toluene metabolism. Comparison of the present results with the findings reported in the literature, however, suggested that the observed effects may be attributable to smoking rather than to drinking habits.

Increase in sister chromatid exchange rates in association with occupational exposure to N,N-dimethylformamide

The effects of occupational exposure to N,N-dimethylformamide (DMF) on sister chromatid exchange (SCE) rates were studied in peripheral lymphocytes from 22 DMF-exposed women (aged 22-52 years) in comparison with 22 sex-, age-, and residence-matched controls. All subjects were nonsmokers and nondrinkers as confirmed by medical interview. The 22 pairs were divided by the intensity of exposure to DMF into 3 subgroups of high-exposed (8 pairs with mean DMF exposure at 5.8 ppm), middle-exposed (5 pairs with DMF at 0.7 ppm in combination with toluene at 0.9 ppm), and low-exposed (9 pairs with DMF at 0.3 ppm). The SCE rates were significantly higher in the high (P less than 0.005) and middle (P less than 0.01) exposed than in their matched pairs, and the increase was related to the intensity of DMF exposure.

Hepatitis B virus prevalence in industrialized cities in China

The prevalence of HBV infection was investigated by radioimmunoassay for HBsAg, anti-HBs and anti-HBc in over 1000 workers in large scale factories located in four industrial cities (Jinxi, Shanghai, Wuxi and Xian) in 1987 to 1990. The age dependency of the prevalence was not evident. The overall prevalence rate of those positive for any of the three markers was 62.6%. The rate was significantly (p < 0.01) higher than the rates found in Beijing in a previous study but lower than the values observed in earlier studies.

Prevalence of hepatitis B virus infection markers among factory workers in Beijing, China

Nearly 1,000 serum samples were obtained from apparently healthy workers of both sexes in various factories in Beijing during 1988-1989 and were examined for hepatitis B virus infection markers by radioimmunoassay. The overall prevalence (all ages and both sexes combined) of cases positive for HBsAg, anti-HBs and anti-HBc were 3.7%, 36.6% and 37.7%, respectively and the rate of those negative to any of the three markers studied was 56.1%. The infection rate was lower than the values reported early in the 1980s for Beijing populations or the values for populations in other parts of China.

Sister chromatid exchanges in peripheral lymphocytes of workers exposed to benzene, trichloroethylene, or tetrachloroethylene, with reference to smoking habits

The frequencies of sister chromatid exchanges (SCE) were studied in peripheral lymphocytes from four groups of solvent workers, i.e. 36 nonsmoking women exposed to benzene at about 50 ppm on the average, 38 men and women (male smokers and nonsmokers, and female nonsmokers) exposed to trichloroethylene (TRI) at 7 ppm, 27 men and women (both smokers and non-smokers) with tetrachloroethylene (TETRA) exposure, and 19 workers (both smokers and nonsmokers in men, and nonsmokers in women) exposed to a mixture of TRI (at 8 ppm) and TETRA (at 17 ppm) (TRI + TETRA). The results were compared with the findings in control subjects matched by age, sex, smoking habits and place of residence. No significant increase in SCE frequencies was observed in association with exposure to benzene, TRI, TETRA or TRI + TETRA. The SCE frequency was, however, significantly higher in the TRI-, TETRA- or TRI + TETRA-exposed smoking men than in the concurrent nonsmoking controls of the same sex. Possible synergism between solvent exposure and smoking is discussed.

Excretion of 1,2,4-benzenetriol in the urine of workers exposed to benzene

Urine samples were collected from 152 workers (64 men, 88 women) who had been exposed to benzene, 53 workers (men only) exposed to a mixture of benzene and toluene, and 213 non-exposed controls (113 men, 100 women). The samples were analysed for 1,2,4-benzentriol (a minor metabolite of benzene) by high performance liquid chromatography. The time weighted average solvent exposure of each worker was monitored by diffusive sampling technique. The urinary concentration of 1,2,4-benzentriol related linearly to the intensity of exposure to benzene both in men and women among workers exposed to benzene, and was suppressed by toluene co-exposure among male workers exposed to a mixture of benzene and toluene. A cross sectional balance study in men at the end of the shift of a workday showed that only 0.47% of benzene absorbed will be excreted into urine as 1,2,4-benzenetriol, in close agreement with previous results in rabbits fed benzene. The concentration of 1,2,4-benzenetriol in urine was more closely related to the concentration of quinol than that of catechol. The fact that phenol and quinol, but not catechol, are precursors of 1,2,4-benzentriol in urine was further confirmed by the intraperitoneal injection of the three phenolic compounds to rats followed by urine analysis for 1,2,4-benzenetriol.

Blood cadmium levels in the populations of 3 Chinese cities

Blood samples were collected from male and female factory workers aged greater than or equal to 16 years (with no occupational exposure to metals including cadmium) in the 3 cities of Hefei (323 subjects), Shenyang (78 subjects), and Jinxi (137 subjects) in China from 1985 to 1987. The samples were analyzed for cadmium in a single laboratory by automated flameless atomic absorption spectrophotometry under strict quality control. The effect of smoking was evident in Hefei, Shenyang and Jinxi, while the effect of aging was not apparent. There were no sex or regional differences in blood cadmium levels in non-smokers in the 3 cities (e.g., 1.2, 1.3 and 1.4 micrograms/l as geometric means in non-smoking women in Hefei, Shenyang and Jinxi, respectively). There was general agreement in blood cadmium levels between the present results and the values reported in the literature, although the latter values were generally based on small study populations.

Blood cadmium levels in the populations of Masan, Korea, and Miyagi, Japan: an inter-regional comparison

Blood samples were collected from factory workers (with no occupational exposure to metals including cadmium) in Masan (167 subjects), Korea, in 1986, and Miyagi prefecture (270 subjects) Japan, in 1987. The samples were analyzed for cadmium in a single laboratory by flameless atomic absorption spectrophotometry under strict quality control. The effect of aging was detected in Masan and possibly also in Miyagi. The effect of smoking was evident among male smokers in Miyagi. Comparison with findings in a sister study on blood cadmium levels in China (taking the effects of smoking and aging into account) showed regional differences: the levels were lower in China, higher in Korea and probably highest in Japan. The smoking-associated increase in blood cadmium level per cigarette was 2-3 times higher in China than in Japan. The blood cadmium levels in the study regions appeared to be associated with the cadmium content of local rice as well as with local rice-eating habits.

Hepatitis B virus infection among women in a shoe factory in Korea

One hundred and sixty five Korean women in a shoe factory in Masan, Korea were evaluated on hepatitis B virus infection by solid-phase radioimmunoassay in 1986. The participants were women of child-bearing ages, mostly in 20's and 30's. About two thirds (105/165) of the subjects had serological evidence of past or present hepatitis B virus infection, and 17% (28/165) were HBsAg-positive. In view of possible risk of vertical transmission of hepatitis B virus, further epidemiological study was considered necessary to establish preventive measures.

Urinary t,t-muconic acid as an indicator of exposure to benzene

A method for rapidly determining t,t-muconic acid (MA) by high performance liquid chromatography was developed and successfully applied to urine samples from 152 workers exposed to benzene (64 men, 88 women) and 213 non-exposed controls (113 men, 100 women). The MA concentrations in urine correlated linearly with time weighted average benzene concentrations in the breath zone air of workers. A cross sectional balance study showed that about 2% of benzene inhaled is excreted into the urine as MA. The MA concentrations in the urine of the non-exposed was below the detection limit (less than 0.1 mg/l) in most cases, and the 95% lower confidence limit of MA for those exposed to benzene at 5 ppm (5.0 mg/l as a non-corrected value) was higher than the 97.5%-tile values for the non-exposed (1.4 mg/l). In practice, it was possible to separate those exposed to 6-7 ppm benzene from the non-exposed by means of urine analysis for MA. The urinary MA concentration was suppressed by coexposure to toluene.

Urinary vanadium as a biological indicator of exposure to vanadium

Vanadium was determined in urine and blood of two workers (Worker Nos. 1 and 2 with direct exposure to vanadium pentoxide) and 13 fellow workers (with indirect or no vanadium exposure), and the results were compared by means of personal and stationary sampling of vanadium in air. Worker No. 1, a foreman with the heaviest exposure to vanadium, had a green tongue, complained of frequent productive coughing, and excreted 47 to 124 ng/ml vanadium in his late morning and mid-afternoon urine. Worker No. 2, a helper to the foreman with less exposure, had no green tongue or subjective complaints, and excreted no vanadium at a measurable level even in his mid-shift urine. No vanadium was detected in urine samples from other workers, nor in blood from all workers including Worker Nos. 1 and 2. Application of inductively coupled plasma emission spectrometry to measurement of vanadium in biological materials is discussed.

Relationship between vapor exposure and urinary metabolite excretion among workers exposed to trichloroethylene

The exposure-excretion relationship was investigated in 140 trichloroethylene (TRI)-exposed workers and 114 nonexposed controls. The time-weighted average intensity of exposure to TRI during the shift as measured by the diffusive sampling method was compared with metabolite levels in the urine collected at the end of the shift in the second half of a working week, when the urinary metabolite levels are expected to reach a maximum. The TRI levels in breathing zone air of the exposed workers were mostly below 50 ppm. The urinary metabolite levels (i.e., total trichloro-compounds, trichloroethanol, and trichloroacetic acid) increased as a linear function of the TRI exposure. The relationship between the two exposure indicators was statistically significant in men, women, and both combined. The cross-sectional balance study at the end of the shift revealed that about 4% of TRI absorbed will be excreted at the end of the shift, in agreement with the long biological half-life of this chlorinated hydrocarbon solvent. A possible ethnic difference in the metabolism of TRI is discussed.

Dose-excretion relationship in tetrachloroethylene-exposed workers and the effect of tetrachloroethylene co-exposure on trichloroethylene metabolism

Personal monitoring of 8-hour time-weighted average intensity of exposure with diffuse samplers and analysis of shift-end urine for total trichloro-compounds (TTC) and other metabolites were conducted in two groups of workers in China, one (121 subjects) exposed to tetrachloroethylene (TETRA) alone, and the other (38 subjects) exposed to a mixture of TETRA and trichloroethylene (TRI). Urinalysis was also performed on samples from 103 non-exposed controls. A linear exposure-excretion relationship could be observed in both groups of workers. Comparison of these results with those of Japanese TETRA-workers suggested the presence of ethnic difference in TETRA metabolism. Urinary metabolite levels were markedly lower in the mixed (TETRA + TRI) exposure group as compared to previous findings in a group exposed to TRI alone. The observation indicates that metabolism of TRI is suppressed by the co-exposure to TETRA in humans.

Determination of catechol and quinol in the urine of workers exposed to benzene

Time weighted average concentrations of benzene in breathing zone air (measured by diffusive sampling coupled with FID gas chromatography) and concentrations of catechol and quinol in the urine (collected at about 1500 in the second half of a working week and analysed by high performance liquid chromatography) were compared in 152 workers who were exposed to benzene (64 men, 88 women). The concentration of urinary metabolites was also determined in 131 non-exposed subjects (43 men, 88 women). There was a linear relation between the benzene concentrations in the breathing zone and the urinary concentrations of catechol and quinol (with or without correction for urine density) in both sexes. Neither catechol nor quinol concentration was able to separate those exposed to benzene at 10 ppm from those without exposure. The data indicated that when workers were exposed to benzene at 100 ppm about 25% of benzene absorbed was excreted into the urine as phenolic metabolites, of which 13.2%, 1.6%, and 10.2% are phenol, catechol, and quinol, respectively.

Increased subjective symptom prevalence among workers exposed to trichloroethylene at sub-OEL levels

Over 100 workers exposed to trichloroethylene (TRI) mostly at less than 50 ppm during the production or vapor degreasing operation and about an equal number of the non-exposed control workers were examined for subjective symptoms, hematology, serum biochemistry, and sugar, protein and occult blood in urine. Essentially all the clinico-laboratory tests stayed normal, and there was no significant differences in the findings between the exposed and the controls. Thus, no clinically significant effects of TRI exposure were found in the blood and liver functions among the exposed workers as compared with the controls. The prevalence of the subjective symptoms was, however, significantly higher in the exposed group than in the controls, and dose-response relationship could be established in some selected symptoms such as nausea, heavy feeling in the head, forgetfulness, tremor in extremities, cramp in extremities and dry mouth, although the exposure was low. The findings warrant further attention to the effects of TRI especially on the central nervous system at the concentration lower than e.g., 50 ppm.

Mutual metabolic suppression between benzene and toluene in man

The exposure intensity during a shift and the metabolite levels in the shift-end urine were examined in male workers exposed to either benzene (65 subjects; the benzene group), toluene (35 subjects; the toluene group), or a mixture of both (55 subjects; the mixture group). In addition, 35 non-exposed male workers (the control group) were similarly examined for urinary metabolites to define background levels. A linear relationship was established between the intensity of solvent exposure and the corresponding urinary metabolite levels (i.e. phenol, catechol and quinol from benzene, and hippuric acid and o-cresol from toluene) in each case when one of the three exposed groups was combined with the control group for calculation. Comparison of regression lines in combination with regression analysis disclosed that urinary levels of phenol and quinol (but not catechol) were lower in the mixture group than in the benzene group when the intensities of exposure to benzene were comparable, indicating that the biotransformation of benzene to phenolic compounds (excluding catechol) in man is suppressed by co-exposure to toluene. Conversely, metabolism of toluene to hippuric acid was suppressed by benzene co-exposure. Conversion of toluene to o-cresol was also reduced by benzene, but to a lesser extent. The significance of the present findings on the mutual suppression of metabolism between benzene and toluene is discussed in relation to solvent toxicology and biological monitoring of exposure to the solvents.

Prevalence of serological hepatitis B markers in a working population in Hefei, China

Hepatitis B surface antigen and antibody (HBsAg and anti-HBs, respectively) prevalence was examined by means of solid-phase radioimmunoassay in 503 serum samples obtained from factory workers (230 men and 273 women) in Hefei, the capital city of Anhui Province, China, in 1985. The prevalence of HBsAg-positlve cases was 8% and that of anti-HBs-positive cases was 46%; the overall prevalence rate was 53% when the positivity in either of the two was considered to be indicative of hepatitis B virus (HBV) infection. There was no significant sex difference in the rate, whereas anti-HBs rate was slightly elevated in accordance with increased age. The review and evaluation of existing data in 14 articles led to a conclusion that the current HBV prevalence among Chinese populations will be in the range of 50% to 60%.

Possible ethnic difference in toluene metabolism: a comparative study among Chinese, Turkish and Japanese solvent workers

Toluene metabolism was studied in 192 Chinese workers in comparison with that in 130 Japanese and 17 Turks. Time-weighted average concentrations of toluene in the breathing zone of workers were measured utilizing passive dosimeters, and hippuric acid (HA) and omicron-cresol (omicron C) concentrations in shift-end spot urine samples by high-performance liquid chromatography (HPLC) and gas chromatography (GC), respectively. Under similar exposure conditions, male Japanese excreted almost twice as much HA as male Chinese, although such difference was less marked between female Chinese and Japanese. In contrast, the excretion of oC did not differ between the two ethnic groups. The ratio of oC over HA was highest among Turkish workers followed by Chinese, and lowest among Japanese. Possible roles of differences in toxicogenetics as well as in life patterns were discussed.

Quantitative relation of urinary phenol levels to breathzone benzene concentrations: a factory survey

Urine samples were collected from 64 men and 88 women in shoe factories and printing plants at the end of a seven hour day shift in the latter half of a week in spring. Urine samples were also taken from 43 men and 88 women in the same factories but who were not exposed to solvents. Exposure to benzene during the shift was monitored by passive dosimeters. Both phenol in urine and benzene in activated carbon were analysed with FID gas chromatographs. The urinary concentrations of phenol were linearly related to the time weighted average concentrations of benzene in the breathzone air; the variation was so small that those exposed to 10 ppm benzene could be separated from the non-exposed at least on a group basis when the phenol concentration was corrected either for creatinine concentration or for specific gravity. The urinary phenol concentrations corresponding to 10 ppm benzene were 47.5 mg/l (as observed), 57.9 mg/g creatinine, or 46.6 mg/l (specific gravity 1.016).

Increased o- and p-cresol/hippuric acid ratios in the urine of four strains of rat exposed to toluene at thousands-ppm levels

Rats (Fisher, Wistar, Donryu and Sprague-Dawley strains) were exposed to 5 approximately 3500 ppm toluene for 8 h, and urine samples were analyzed for hippuric acid and cresols. While hippuric acid increased in proportion to the exposure concentration, a sharp increase in o-cresol excretion was observed at high toluene concentrations so that the o-cresol/hippuric acid ratio was elevated after 500 approximately 3500 ppm exposures. Changes in the p-cresol: hippuric acid ratio were less marked. There were strain differences in toluene metabolism. Fisher rats were highest and Sprague-Dawley rats lowest in o-cresol excretion and in the o-cresol: hippuric acid ratio, whereas Wistar rats excreted p-cresol most abundantly.

Inhibition of mouse natural killer activity by cholera toxin

The treatment of mouse spleen cells with cholera toxin (CT) extracted from Vibrio cholerae greatly reduced natural killer (NK) activity. The inhibition of NK activity was rapidly induced by CT treatment and persisted in the absence of CT. Even a very small amount of CT, such as 0.1 ng/ml, was effective in inhibiting NK activity. The inhibitory effect of CT on NK activity was lost upon preabsorption of CT with brain tissues, but not upon preabsorption with liver or kidney tissues.

Erythrocyte rosette forming activity of macrophage

Erythrocyte rosette forming activities of the rat lung macrophage, peritoneal macrophage, Kupffer cells and expressed splenic cells were studied. The erythrocytes employed were fresh human red blood cell (RBC), fresh sheep RBC (SRBC), and tanned SRBC coated with bovine albumin or with bovine gamma-globulin. The macrophages were mixed with RBC at a ratio of 1 to 100 or 200 in gelatin veronal buffer or phosphate buffered saline. The experiments were carried out at 4 degrees C. No autologous serum nor anti-RBC serum was added to the experimental system. 10 to 20 per cent of the lung macrophages formed rosette and their entire surfaces were covered with RBC. The peritoneal macrophage and Kupffer cells were also capable of forming rosette with fresh SRBC as well as with SRBC coated with bovine albumin or with bovine gamma-globulin. Examinations for cell surface immunoglobulin of alveolar macrophage, peritoneal macrophage, Kupffer cells and splenic cells revealed that alveolar and peritoneal macrophages apparently possessed surface gamma-globulin and that almost all of these macrophages possessed surface immuno-globulin. In order to examine the effect of different natures of SRBC on in vivo phagocytosis, rats were immunized with SRBC by injecting various SRBC into the femoral or the portal vein and the hemagglutinin titer was studied. The maximum hemagglutinin titer was observed in the rat injected with fresh SRBC into the femoral vein and the minimum hemagglutinin titer was observed in the splenectomized rat injected with fresh SRBC and in the rat injected with SRBC coated with albumin or gamma-globulin into the femoral or portal vein. Immunological role of Kupffer cells was discussed.

Clinical significance of Congo red test

Clinical significance of Congo red test was studied, especially on its relation to the liver function and amyloidosis. No significant relationship was observed between Congo red test and Indocyanin green test in cases of various liver diseases except liver cirrhosis. Histological studies also revealed that there were no pathologic features specifically affecting Congo red index (CRI), even though CRI in cases of various liver diseases tended to be increased as compared with other diseases. As a cause of increased CRI which was seen most remarkably in cases of liver cirrhosis, obstructive change of the liver blood flow followed by the hepatic tissue damage is suspected. The concept that Congo red test is a kind of the hepatic excretory function test does not have, from our data, enough evidence. The present study confirmed our previous data on the fate of Congo red injected intravenously, which indicated that this test is one of the best tests available for RES function and this test is related mainly to Kupffer's cell rather than to the so-called hepatic excretory function. There were no cases which showed notable decrease of CRI in experimental amyloidosis and in clinical amyloidosis, and it can be said that Congo red test is not the best test for the diagnosis of amyloidosis.

Lympho-reticuloendothelial activity of early gastric carcinoma

The lympho-reticuloendothelial activities of 54 cases of early gastric carcinoma were studied. Morphological blastoid transformation of lymphocyte by the addition of phytohemagglutinin-P (PHA-P) was disturbed in half of the patients. The DNA synthesizing activity of lymphocyte was not stimulated by PHA-P in the cases of advanced carcinoma but it was stimulated in the cases of early carcinoma. The tuberculin reaction was negative in 30% of the cases of early carcinoma. The reticuloendothelial system (RES) activity studied through the congo red method revealed that 86% of the cases of early carcinoma had disturbed RES function.