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To elucidate factors associated with the very low risk of gastric neoplasia in Yogyakarta, Indonesia, approximately 1/50 of the level in Japan, we recruited 52 male and 39 female participants from the general populace in the city of Yogyakarta in October 2003. Helicobacter pylori IgG antibodies were found in only 5% (0-13) (95% confidence interval) and 4% (0-9) for Javanese males and females, respectively, and were statistically lower than the 62% (58-65) and 57% (53-60), respectively, in Japanese. Furthermore, positive findings of pepsinogen test were only 0 and 2% (0-6) for males and females, in Yogyakarta, and were again significantly lower than the 23% (22-25) and 22% (20-23), in Japan. The very low incidence of stomach cancer in Yogyakarta may be due to a low prevalence of H. pylori infection and chronic atrophic gastritis.

In order to evaluate the load on the low back of care workers in nursing homes for the elderly, basic activities and working postures were analyzed for six care workers using the 30-s snap reading method. The trunk inclination angle (TIA) was also measured continuously using an inclination monitor. The analysis of basic activities showed that 22.5% and 21.1% of the workshift were spent on 'bathing and ablution' and 'meal', respectively, and 9.3%, 8.7% and 8.3% were spent on 'assistance with elimination', 'assistance with moving and repositioning' and 'exchange of bed sheet', respectively. Total of the assistance activity was 43.7% of the workshift. The analysis of working posture showed that 'standing' and 'standing bent forward' accounted for 36.1% and 29.5%, respectively, of the workshift. Total of three postures loading the low back ('standing bent forward', 'squatting', 'kneeling') accounted for 39.0%. The time spent in TIA of 20 degrees or more was 45.7%. The postures loading the low back during 'bathing and ablution', 'exchange of bed sheet' and 'assistance with elimination' account for 68.3%, 58.2% and 49.6%, respectively, which suggests that these activities load the low back of the care workers considerably.

Objectives: In order to clarify the effect of lead on higher cerebral functions, lead-exposed workers (Pb group) and controls were examined for event-related potentials. Subjects and Methods: Fourteen lead-exposed workers with a mean age of 57.1 yr (SD=4.27, range 48-64; lead concentration of whole blood ranged from 33 to 106 μg/dl with a mean of 58.6 and SD 28.6 μg/dl) and 19 agematched control workers with a mean age of 57.3 yr (SD=4.80, range 48-65) were examined. Visual P300 was recorded by button pushing to the target image (minute checkerboard pattern, 20%), and the NO-GO potential by no button pushing to the target image (same as above, 50%). Results: Latencies of P300 in the Pb group (475 ± 46.0 ms) were significantly delayed compared with those in controls (407 ± 42.4 ms, p

Vesicles and bullae formation is rare in dermatomyositis. We describe a 60-year-old woman who presented with vesiculobullous dermatomyositis with panniculitis and no muscle disease.

Inhalation toxicokinetics of p-dichlorobenzene ( p-DCB) in humans was evaluated, and the amounts of daily absorption and internal accumulation were estimated in order to obtain fundamental data for the risk assessment of chronic low-level exposure in the general population. Seven male subjects continuously inhaled about 2.5 ppm of p-DCB vapor for 1 h, and the concentration-time courses of p-DCB in their exhaled air and serum and of urinary 2,5-dichlorophenol (2,5-DCP), a major metabolite of p-DCB, were examined. The toxicokinetics of p-DCB was evaluated on the basis of the time courses using a linear two-compartment model. The amounts of p-DCB absorbed daily and the internal accumulation in chronic low-level exposure were extrapolated using the estimated toxicokinetic parameters. p-DCB was transferred from inhaled air to the body with a constant high absorption rate during exposure. The major route for elimination from the body was urinary excretion followed by metabolism, not exhalation. However, during 9-11 h after the start of exposure, the fraction of p-DCB excreted in urine was only 5-16% of the amount absorbed. Furthermore, most of the absorbed p-DCB seemed to be distributed rapidly to the tissues, such as fat, according to toxicokinetic analysis. Consequently, p-DCB seems to require a long time to be completely eliminated from the body. The amounts of daily absorption and internal accumulation were extrapolated to average 0.27 mg/day and 2.9 mg, respectively, in the subjects exposed chronically to 1 ppb of p-DCB. The amount absorbed daily agreed approximately with that extrapolated from rats which inhaled p-DCB in our previous study.

A methanol extract from Pogostemon cablin showed a suppressive effect on umu gene expression of SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide). The methanol extract was re-extracted with hexane, dichloromethane, butanol, and water. A dichloromethane fraction showed a suppressive effect. Suppressive compounds against furylfuramide in the dichloromethane fraction were isolated by SiO(2) column chromatography and identified as 7,4'-di-O-methyleriodictyol (1), 7, 3',4'-tri-O-methyleriodictyol (2), and 3,7,4'-tri-O-methylkaempferol (3). In addition, three flavonoids, ombuine (4), pachypodol (5), and kumatakenin (6), were isolated and identified from the dichrolomethane fraction. Compounds 1 and 3 suppressed50% of the SOS-inducing activity at0.6 micromol/mL, and the ID(50) values of both compounds were 0.25 micromol/mL. Compound 2 showed a weakly suppressive effect (17%) at a concentration of 0.6 micromol/mL, and compounds 4-6 did not. These compounds were also assayed with 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which requires liver metabolizing enzymes. Compounds 3-6 suppressed80% of the SOS-inducing activity of Trp-P-1 at0.06 micromol/mL, and compounds 1 and 2 suppressed 87 and 63% at a concentration of 0.3 micromol/mL. In addition, these compounds were assayed with activated Trp-P-1, and the suppressed effects of these compounds were further decreased when compared to Trp-P-1. The antimutagenic activities of these compounds against furylfuramide, Trp-P-1, and activated Trp-P-1 were assayed by the Ames test using S. typhimurium TA100.

Respiratory uptake was investigated for 10 polar organic solvents with high blood/air partition coefficients (lambda(blood/air)): ethyl acetate (lambda(blood/air), 77), methyl iso-butyl ketone (90), methyl acetate (90), methyl propyl ketone (150), acetone (245), iso-pentyl alcohol (381), iso-propyl alcohol (848), methyl alcohol (2590), ethylene glycol monobutyl ether (EGBE, 7970), and propylene glycol monomethyl ether (PGME, 12380). Test-air concentrations (Cinh) were 25 to 200 ppm. Four healthy male volunteers inhaled the test air for 10 min at rest and then room air for 5 min. The percentage of solvent in the end-exhaled air and in the mixed-exhaled air increased after the start of the test-air respiration, and reached a quasi-steady-state level within a few min. The speeds of these increases at the start of the test-air respiration became lower as lambda(blood/air) increased. The mean uptakes (U) for the last five min of the test air respiration were 67.3, 52.9, 60.4, 53.0, 52.6, 63.0, 60.3, 60.8, 79.7, and 81.3%, respectively, for ethyl acetate, methyl iso-butyl ketone, methyl acetate, methyl propyl ketone, acetone, iso-pentyl alcohol, iso-propyl alcohol, methyl alcohol, EGBE and PGME. Thus, U values of the alcohols were higher than those of the ketones and lower than the glycol ethers. The overall view, except for esters, showed that U increased with lambda(water/air) increases. This tendency can be explained by a hypothesis that solvent absorbed in the mucus layer of the respiratory tract is removed by the bronchial blood circulation. U values of ethyl acetate and methyl acetate were higher than those of methyl iso-butyl ketone and methyl propyl ketone, though the lambda(blood/air) values of these esters were nearly equal to those of the ketones. For the respiration of the esters, their metabolites, ethyl alcohol and methyl alcohol, were detected in the exhaled air. The exhalation percentage of the metabolites increased after the start of test-air respiration and reached a quasi-steady-state level of 2 and 3%, respectively, by the 5th min. These data suggest that removal of the solvent via metabolism in the wall tissue of the respiratory tract plays an important role for the esters.

In order to evaluate the load on the low back of teachers in kindergartens, basic activity and working posture were analyzed for four teachers by means of video recording. The trunk inclination angle (TIA) was also measured continuously during full workshifts for 12 kindergarten teachers by means of an inclination monitor. The kindergarten teachers spent 67% of the workshift on activities in contact with children, "indoor group childcare", "indoor free playing", "outdoor childcare", "preparation and clearing away" and "help and care", and did not take a recess during the workshift. They spent 36% of the workshift in three working postures with the load on the low back, "standing bent forward", "squatting" and "kneeling". Cumulative time at a TIA of 20 degrees or more represented 43% of the workshift. The frequency of trunk-lifting from severe bending forward (TIA > 45 degrees) was 95 times/hr on average. A comparison of the kindergarten teachers and nursery teachers in 4-5 year age classes showed that the time distributions of basic activities were generally similar to each other. Although the time distributions of working postures were also similar, time spent "standing bent forward", "squatting" and "kneeling" was longer in the kindergarten teachers than in the nursery teachers. Cumulative time at a TIA of 45 degrees or more was significantly longer in the kindergarten teachers. Although the frequency of trunklifting was not significantly different, the kindergarten teachers tended to lift their trunk more frequently. The present study found that the load on the low back was considerably great in the kindergarten teachers.

In order to clarify the bioavailability of lead in plasma (PbP), we performed a study on five workers in a Japanese factory manufacturing lead glass-based paints. Blood and urine samples were obtained over a period of 15 months, during which time the workers took it in turns to perform sifting work (with the highest level of lead exposure) for 1-month periods. A total of 75 sets of blood and urine samples were thus obtained. We determined whole blood lead (PbB), PbP, Urinary coproporphyrin (CPU), urinary delta-aminolevulinic acid (ALAU), urinary lead (PbU) and ALA in plasma (ALAP). In the 15 sets of samples obtained at the end of the period with a high level of lead exposure, PbP correlated significantly with ALAU, CPU, PbU and ALAP, but PbB correlated significantly only with PbU. In the 60 sets of samples obtained following a low level of lead exposure, correlation coefficients between the concentrations of PbP and of ALAU, CPU and PbU exceeded those between the concentrations of PbB and of ALAU, CPU and PbU. These findings indicate that PbP is a better dose indicator of lead biochemically available for heme synthesis and that PbU has a closer correlation with PbP than with PbB.

A method for the determination of delta-aminolevulinic acid in plasma of lead-exposed workers by high-performance liquid chromatography with fluorescence detection of a fluorescent delta-aminolevulinic acid derivative (2-methylidineamino-3,5-diacetyl-4,6-dimethylpropionic acid) was established. The detection limit of delta-aminolevulinic acid in plasma was 0.01 microgram/ml at a signal-to-noise ratio of 5:1. A linear correlation was obtained between the amounts of delta-aminolevulinic acid injected from 0.01 to 0.5 microgram/ml (r = 0.999). The recovery of 0.05 and 0.1 microgram/ml of delta-aminolevulinic acid added to plasma with various concentrations of delta-aminolevulinic acid in plasma ranged from 80.0 to 100.8%. This method, combined with the use of an automatic sampler, should facilitate the routine measurement of delta-aminolevulinic acid in plasma.

The authors measured the concentrations of serum dioxins and urinary estrogen metabolites in 57 male waste incinerator workers to determine whether dioxin influenced the metabolism of estrogens. Concentrations of serum dioxin levels and urinary estrogen metabolites, such as estrone, 17beta-estradiol, 2-hydroxyestrone, 2-methoxyestrone, 2-hydroxyestradiol, 2-methoxyestradiol, 4-hydroxyestrone, 4-hydroxyestradiol, 4-methoxyestradiol, 16-hydroxyestrone, and estriol from the workers were measured. An analysis of covariance showed that mean estriol concentrations, adjusted for confounding factors among 3 serum dioxin levels, indicated a progressive increase with increasing serum dioxin level: 1.30, 1.41, and 2.02 nmol/mol creatinine at30.3, 30.3-39.7, and39.7 pg toxicity equivalent quantity/g lipid, respectively (F = 3.56, p = .036). This study showed that dioxin acts to metabolize estrogens to 16-hydroxyestrogens rather than to 2- or 4-hydroxyestrogens.

The aims of the present study were to clarify the work environment contamination by antineoplastic drugs in a hospital ward and to assess the genotoxic risks to nurses who routinely handle antineoplastic drugs in Japan. The exposed group consisted of 19 female nurses who routinely handled antineoplastic drugs. The control group consisted of 18 female nurses who did not handle antineoplastic drugs in the same hospital as the exposed group. The genotoxicity of the 19 antineoplastic drugs used in the hospital ward and 8 wipe samples of the workbench after handling of antineoplastic drugs were measured using the umu assay. Lymphocyte DNA damage (tail length) was measured with alkaline methods of the single cell gel electrophoresis assay (comet assay). Of the 19 antineoplastic drugs, dacarbazine, bleomycin, daunorubicin, doxorubicin, pirarubicin, carboplatin, cisplatin and etoposide induced genotoxicity. Of the 8 sampling d, the umu activity of the wipe sample was positive on 3 d. Contamination of the workbench was found when the nurses handled more drugs than on other days. The medians of the tail length in the comet assay were 8.5 and 5.1 microm, respectively, for the exposed and control groups, with a significant difference (p=0.004 by Mann-Whitney's U-test). In the present study, the nurses of the exposed group were considered to have been exposed to antineoplastic drugs and lymphocyte DNA damage of the exposed group was suggested to be induced by antineoplastic drugs.

A 53-year-old woman had had a pale-brown lesion on her right cheek and neck from birth. Since she was about 40 years old, part of the lesion had gradually elevated and increased in size. At the first examination, there was a huge mass measuring 110 × 70 × 35 mm on the right cheek. A wide local excision of the area including a superficial parotidectomy and submandibular lymph node dissection was performed, followed by full thickness skin grafting. Histological examination of the tumor revealed an invasive dermal neoplasm characterized by lobes that were composed of foamy cells stained with Sudan-IV mixed with many atypical cells showing remarkable variation in the shapes and sizes of their nuclei. The surrounding epithelial changes were consistent with nevus sebaceus. From these findings, the gigantic tumor was diagnosed as a sebaceous carcinoma arising in nevus sebaceus.

Objectives: To investigate the effect of dioxin on the formation of oxidative DNA damage and urinary mutagenicity, we measured the concentrations of serum dioxins and lymphocytic 8-hydroxydeoxyguanosine (8-OH-dG) in 57 male waste incinerator workers, urinary 8-OH-dG and urinary mutagenicity in 29 male waste incinerator workers. Methods: Information about the subjects was obtained from a questionnaire. Concentrations of polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofuran (PCDF), and coplanar-polychlorinated-biphenyl (Co-PCB) in serum samples from the workers were measured with a high-resolution gas chromatograph /high-resolution mass spectrometer. Lymphocytic and urinary 8-OH-dG levels were measured with a high-performance liquid chromatography-electrochemical detector system. The urinary mutagenicity was measured with umu assay. Results: The lymphocytic 8-OH-dG level showed a negative association with the serum dioxin level (total value of TEQ-PCDD, PCDF, and Co-PCB). Urinary 8-OH-dG did not show correlation with serum dioxin level, but showed positive correlation with the smoking index. Conclusions: With respect to the subjects‘ serum dioxin level, dioxin did not increase the urinary 8-OH-dG level by oxidative DNA damage, but upregulation of the primary defenses with oxidative damage and/or DNA repair system activity might have occurred.

Relationships between concentrations of polychlorodibenzo-p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs) in deposited dust and those in the serum of incinerator workers were examined at 13 municipal incineration plants. The following results were found. 1) Dust analysis showed that dominant constituents were octachlorodibenzo-p-dioxin (OCDD) and 1, 2, 3, 4, 6, 7, 8-heptachlorodibenzo-p-dioxin (HpCDD) among PCDDs, and 1, 2, 3, 4, 6, 7, 8-heptachlorodibenzofuran (HpCDF) and octachlorodibenzofuran (OCDF) among PCDFs. The toxicity equivalents (TEQs) of total PCDDs and PCDFs in the deposited dust were 0.54 to 33 ngTEQ/g, which were about 1,000 to 10,000 times as high as those in general soil. 2) The mean of serum TEQ of PCDDs, that of PCDFs and that of total PCDDs and PCDFs in the incinerator workers were 16, 12 and 28 pg TEQ/g lipid, respectively, for all the incinerator workers. Concentrations of hexachlorodibenzofurans (HxCDFs) and HpCDFs in the serum were significantly higher in the incinerator workers than the general population, which suggests that these workers had inhaled these chemicals during their work. 3) The concentration of 1, 2, 3, 4, 6, 7, 8-HpCDF and the TEQ value of PCDFs and in the serum were positively correlated with those in dust except for three plants where large-scale remodeling of the equipment was conducted within the past seven years. Consequently, deposited dust analysis may be useful for judging whether health examination containing blood dioxin measurement is necessary or not.

The methanol extract from Citrus aurantium showed a suppressive effect on umu gene expression of SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide). The methanol extract from C. aurantium was successively re-extracted with hexane, dichloromethane, butanol, and water. A dichloromethane fraction showed a suppressive effect. The suppressive compounds in the dichloromethane fraction were isolated by SiO(2) column chromatography and identified as tetra-O-methylscutellarein (1), sinensetin (2), and nobiletin (3) by EI-MS and (1)H- and (13)C NMR spectroscopy. These compounds suppressed the furylfuramide-induced SOS response in the umu test. Gene expression was suppressed 67%, 45%, and 25% at a concentration of 0.6 micromol/mL, respectively. The ID(50) value (50% inhibition dose) of compound 1 was 0. 19 micromol/mL. These compounds were assayed with other mutagens, 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which requires liver metabolizing enzymes, activated Trp-P-1, and UV irradiation. These compounds showed of all mutagen-induced SOS response in the umu test. In addition, compounds 1-3 exhibited antimutagenic activity in the S. typhimurium TA100 Ames test.

There is now convincing evidence that CD8+ T cells can be activated by professional antigen-presenting cells which present antigens derived from non-lymphoid tissues in association with MHC class I molecules in the draining lymph nodes. This mechanism, referred to as cross-presentation, enables the immune system to respond to those microorganisms that infect only non-lymphoid tissues. Consistent with this view, cross-presentation was found to focus on antigens expressed in high concentrations and those released from dying cells, which can be expected to result from viral infections. Recent evidence, however, demonstrates that high dose self antigens can be cross-presented constitutively, resulting in the activation of autoreactive CD8+ T cells. This does not lead to auto immunity under physiologic conditions, but to CD95-mediated deletion of the T cells. Cross-presentation can thus engage a well-defined pathway of antigen-induced T-cell death and purge the immune system of autoreactive CD8+ T cells. Low dose self antigens are not cross-presented and are consequently ignored. The immune system therefore uses two strategies to avoid CD8+ T-cell-mediated autoimmunity in the periphery: deletion of autoreactive CD8+ T cells responding to high dose self antigens and ignorance of self antigens expressed at low concentrations.

In order to evaluate the load on the low back of teachers in nursery schools, basic activity, working posture, child-lifting, and desk-lifting were analyzed for eight nursery teachers using video recording. The trunk inclination angle (TIA) was also measured continuously during full workshifts for 20 nursery teachers using an inclination monitor. The nursery teachers in the 0-1 (year) age class more often adopted low working postures, "sitting on the floor" and "kneeling," while teachers in the 4-5 age class more frequently adopted high working postures, "standing" and "sitting on a chair." The mean of TIA among all subjects was 20 degrees. The time spent at a TIA of more than 20 degrees represented 43% of the workshift. The mean and time distribution of TIA did not differ between the age classes. The frequency of trunk-lifting from severe bending forward (TIA45 degrees) was 86 times/hour on average. The frequency of trunk-lifting was highest in the 0-1 age class. The number of times of child-lifting was 46 in the 0-1 age class, while it was 1 in the 4-5 age class.

To clarify the chronic effect of lead exposure on the central and peripheral nervous systems (CNS and PNS), we performed neurophysiological tests on 41 lead-exposed male workers. Unexposed workers (controls, N = 39) were examined for auditory brain stem response (ABR), and their ABR parameters were compared with those of 15 lead-exposed workers age-matched to the controls. Neurophysiological tests included those of motor and sensory nerve conduction velocity of the radial nerve (MCV, SCVwa and SCVfw), electroretinograms, pattern reversal visual evoked potential (VEP), ABR, and short-latency somatosensory evoked potentials (SLSEP). Neurophysiological parameters were analyzed by regression analysis [independent parameters: age, exposure duration, and current and time-weighted average lead concentration in whole blood (PbB and TWA-PbB)]. ABR parameters were also tested by Student's t test. Significant negative correlations were found between radial MCV and TWA-PbB and SCVwa and PbB, while significant positive correlations were found between the latency of component N145 of VEP and exposure duration and between the latency of component N20 of SLSEP and PbB. The mean of interpeak latency between component III and V of ABR of 15 lead-exposed workers was significantly prolonged compared with that of the control group. These results suggested that lead exposure has a greater effect on the conduction function in the PNS than in that of the CNS in somatosensory and auditory pathways, and inversely in visual pathway.

T cell tolerance to self antigens is at least partly a reflection of clonal deletion of immature T cells in the thymus. Although it is well accepted that intrathymic tolerance is primarily a reflection of T cell contact with bone-marrow (BM)-derived antigen-presented cells (APC), evidence is presented that thymic epithelial cells (TEC) can contribute to tolerance induction. Studies with thymocytes from BM chimeras suggest that selective contact with antigen on TEC induces clonal deletion of a subset of high-affinity T cells; these cells are primarily responsible for in vivo effector functions such as allograft rejection and induction of lethal graft-versus-host disease. Intrathymic contact with TEC fails to delete the typical low-affinity T cells which mediate cytotoxic responses in vitro when cultured with lymphokines. Deletion of these low-affinity T cells appears to require contact with BM-derived APC. Despite the evidence that self tolerance involves clonal deletion in the thymus, it is often stated that backup mechanisms for tolerance induction must exist in the post-thymic environment, but this has yet to be proved. The competing argument is that normal self/nonself discrimination is solely a reflection of intrathymic tolerance: the failure of T cells to react against tissue-specific antigens is not a reflection of post-thymic tolerance but simply that T cells and tissue-specific antigens are kept segregated.

An interview survey on the health care service for workers employed in small-sized enterprises was conducted in a city of Osaka Prefecture. Items surveyed were: 1) number of full-time and part-time employees by age (less than 39, 40-60, and more than 60 yr) and sex, 2) materials and production process, 3) periodic examinations for general health status and occupational diseases, and others. Of the 526 enterprises interviewed, 459 manufacturers with less than 50 employees were analyzed. The results can be summarized as follows: 1. Of the 459 manufacturers, 72.4% were those with less than 10 workers (the mean number of employees: 8.4). The major type of manufacture was electric parts processing industry. 2. The period health examination has been carried out in 372 enterprises (81.0%). The smaller the size of the company, the lower was the rate of the periodic health examination. 3. In 77.4% of the 372 enterprises, only chest X-ray was an item for the periodic health examination, which was usually carried out at the public health center of the community. 4. The number of enterprises conducting the periodic health examination designated by the Industrial Safety and Health Law (1972) was only 49 (10.7%). 5. Fourteen enterprises (3.1%) have carried out periodic examination for occupational diseases. 6. The periodic examination for degenerative diseases such as hypertension, diabetes mellitus, and other cardiovascular diseases was carried out in 57 enterprises (12.4%). The larger the size of the company, the higher was the rate in which such examination was conducted.(ABSTRACT TRUNCATED AT 250 WORDS)

An assessment of the employee's exposures to industrial hazardous substances using the proposed method described earlier was conducted on 49 workers exposed to lead. As it is assumed that the daily exposure averages are lognormally distributed, geometric standard deviation (sigma g) representing true interday fluctuations of the daily exposures was estimated by personal exposure measurements of every worker for two consecutive days. The estimates (Sg) ranged from 1.00 to 5.35 with a median of 1.4 and a 90% upper limit of 2.4. According to a classification scheme in the proposed method, exposure levels (I to III) were calculated using sigma g of 1.4 and 2.4. An exposure class based on a single day measurement was evaluated and compared to that based on measurements for two consecutive days. As a result, the decision of the exposure levels and classes from only one day monitoring could be made by using both sigma g of 1.4 and 2.4, representing ordinary and high interday fluctuations, respectively. More accurate estimate of geometric standard deviation of interday fluctuations by exposure monitorings would provide a more reliable assessment of the worker's long-term exposure situation.