---

Behavioral Evidence for Modified Receptor Sensitivity in Rat Brain Induced by Methyl Bromide Exposure
Takeshi HONMA, Megumi KANADA and Muneyuki MIYAGAWA
Abstract : To clarify the neurochemical basis of methyl bromide toxicity in rats, we measured changes in the sensitivity of cerebral monoamine, dopamine (DA) and norepinephrine (NE) receptors, using abnormal behavior and locomotor activity as indicators of receptor sensitivity. Apomorphine and clonidine were used as specific agonists of DA (D1 and D2) and NE (a2) receptors, respectively. In the first experiment, rats were exposed to methyl bromide gas at 25-200 ppm for 8hr once or to methyl bromide at 5-50 ppm 8hr a day for 7 days. The intensity of stereotyped oral (STO) behavior produced by an injection of apomorphine, 0.5 mg/kg i.p., was rated over the following 28 days. The STO behavior of rats exposed to methyl bromide (MB rats) was much more intense than in air-exposed (control) rats. This finding strongly suggests that the sensitivity of striatal DA, D1 and D2, receptors to apomorphine was increased by methyl bromide exposure. In the second experiment, rats were exposed to 50 ppm methyl bromide for 8hr once or to 10-50 ppm methyl bromide 8hr a day for 7 days. Seven days after the final exposure, rats were injected with a small dose of apomorphine, 0.3 mg/kg i.p., and the counts of apomorphineinjected locomotor activity (ALA) were recorded. The ALA counts of MB rats were markedly higher than in the control rats. This finding suggests that the DA receptors in the nucleus accumbens of MB rats are more sensitive to apomorphine than those of control rats. In the third experiment, rats were exposed to 50 ppm methyl bromide, 8hr a day for one day or 7 consecutive days, and the degree of attenuation of locomotor activity following clonidine injection (CLA) was rated. CLA counting was performed 7 days after the final exposure. CLA counts in MB rats were not attenuated as much as in the control rats. This indicates that the cerebral NE receptors, i.e., a2-adrenoceptors, of MB rats may be less sensitive to clonidine than those of control rats. Increased behavioral sensitivity to apomorphine was observed in rats even when exposed to 5 ppm (TLV) methyl bromide.

Urinary Mercury Monitoring of University Staff and Students Occasionally Exposed to Mercury Vapor
Tetsuro HONGO, Taku ABE, Ryutaro OHTSUKA, Masako KOMAI, Tomoko OKIYAMA, Keiko AMANO, Teruhiko TOYO-OKA and Tsuguyoshi SUZUKI
Abstract : To monitor the exposure to mercury (Hg) vapor among university staff members and students who occasionally handle elemental Hg in laboratory experiments, urine samples were collected at health examinations conducted by the Health Service Center, University of Tokyo, for six years. Geometric mean of urinary Hg concentrations of 343 samples collected from 234 subjects was 1.61 μg Hg/g creatinine (Cr), with the range of 0.30 to 9.31 μg Hg/g Cr. Elevated urinary Hg levels, i.e. 3 μg Hg/g Cr or higher, were found only among the subjects who worked in several laboratories. This urinary Hg level is judged to correspond to 1-2 μg/m3 of air Hg concentration in working areas. The contribution of dental amalgam fillings to urinary Hg excretion, though it exists, was concluded to be small from the result of multiple regression analysis.

Effect of Lifetime Cigarette Consumption on Time Domain Spirogram Indices
Toshio NAKADATE, Toshihiko SATO, Jun KAGAWA and Takashi YAGAMI
Abstract : A cross-sectional analysis on the dose-related change in time domain spirogram indices induced by lifetime cigarette consumption was conducted to examine the ability of those indices to detect early changes in the lung periphery in comparison with conventional spirometric indices. The subjects were asymptomatic healthy male workers from three occupational cohorts including asbestos workers and welders. They were asked to perform the forced expiration maneuver at least three times to obtain reliable results. A total of 893 subjects were enrolled in the study, and 484 of them who were aged 30 years or more and were free from chronic respiratory sysmptoms and abnormalities in chest radiography and spirometry, were analyzed. Although conventional indices, such as forced expiratory volume in one second and maximal midexpiratory flow, were not significantly different between smokers snd nonsmokers, the standard deviation of transit times and of time constant distribution in smokers were significantly elevated compared with nonsmokers. Furthermore a dose-related change according to lifetime cigarette consumption was observed in those indices. We conclude that time domain spirogram indices, especially the standard deviation of time constant distribution, would be more useful than conventional indices in detecting early changes in the lung periphery.

A Spectrophotometric Method for Determination of Phosgene in Air
Santosh K.DANGWAL
Abstract : A reagent consisting of 0.4% of nitrobenzyl pyridine and 0.5% of sodium acetate in ethanol was found to be applicable as a sampling and coloring solution to a sensitive and relatively specific spectrophotometric determination of phosgene. This method is a modification of the method developed by Noweir et al. An aqueous 0.005% methyl orange pretrap was used to eliminate interference with chlorine and hydrogen chloride which are likely to be encountered in industrial environment. This colour produced by this method was stable for 2 hours, reduced by 3% and 7% after 3 and 4 hours of sampling respectively. The method is so sensitive as to detect phosgene at a concentration of 0.1 μg/ml in the sampling solution with the coefficient of variation (CV) of 4.5%. The collection efficiency of phosgene with the sampling solution was found to be greater than 98% at a sampling rate of 1l/min.

Noise in Aerobic Facilities
Seyed Mohammad MIRBOD, Chiri LANPHERE, Setsuya FUJITA, Yoko KOMURA, Ryoichi INABA and Hirotoshi IWATA
Abstract : Noise levels were evaluated before and during aerobic sessions in 3 aerobic studios. In addition, hearing threshold levels (HTLs) of 10 female aerobic instructors with the mean (±SD) ages of 25.4 (± 2.4) years were measured before and 2 min after an aerobic session. The mean (±SD) of total instruction time of these subjects was 1274.0 (± 704.9) h. Before the aerobic session, noise level was 63 dB(A) and increased to 87 dB(A) during a warm-up period. The highest noise levels of 93-96 dB(A) were recorded during a peak exercise period and decreased to 73 dB(A) during a cool-down period. The dominant spectra of sound pressure levels (SPLs) during the aerobic session were in the frequency range of 1-2kHz at levels of 75-88 dB(C). The mean values of HTL obtaind for each ear of these subjects were between 5 and 15 dB in the frequency range of 1-8kHz. No significant differences in the mean HTLs of pre- and post-aerobic sessions could be obtained. The mean values of HTL of two groups of subjects divided by their total instruction time (n=5 in each group, and p<0.01 in their total instruction time) were quite comparable.

Physiological Indices of Visual Fatigue due to VDT Operation --Pupillary Reflexes and Accommodative Responses--
Susumu SAITO, Midori SOTOYAMA, Shin SAITO and Sasitorn TAPTAGAPORN
Abstract : In spite of the clarification of some significant physiological factors of visual fatigue caused by VDT work, pupillary reflexes have not been studied as to how they are affected after prolonged visual work. This study examined visual function changes objectively in terms of pupillary reflexes and lens accommodative responses after a 4-hr VDT operation task. The relationship between the two functions was also examined. Two measurements in this paper revealed the physiological function changes due to VDT operation. The subjects involved were five students with an average age of 22.6 years. First, near-reflex measurement ascertained decreases in amplitude and the velocity of accommodation function after the visual task. Second, light-reflex measurement revealed a delay of the reflex, an increase in the amplitude of the reflex, and a decrease in pupil size after the visual task. A weak correlation between the decrease in pupil size and accommodation function was found. The occurrence of visual fatigue due to 4-hr VDT operation was also confirmed by CFF measurements and reported subjective visual symptoms in this experiment.

Blood and Urinary Levels of Metals(Pb, Cr, Cd, Mn, Sb, Co and Cu) in Cloisonne Workers
Fumio ARAI, Yukio YAMAMURA, Minoru YOSHIDA and Tsuyoshi KISHIMOTO
Abstract : Blood and urine samples from cloisonne ware workers were assayed for Pb, Cr, Cd, Mn, Sb, Co ad Cu for biological monitoring. Mean blood Pb levels were 47.8 ± 27.3 mug/dl (111-13.3mug/dl) for 49 cloisonne glaze workers, and 0.97 ± 0.47 mug/dl (2.4-0.6 mug/dl) for 62 normal subjects. There was a distinct difference between the 2 groups, and slight differences (p < 0.01) in mean Cr, Cd and Mn levels. There was a distinct difference in mean urinary Pb level between the 2 groups, and slight differences (p < 0.01) in mean Cr, Cd and Mn levels. The correlation coefficient, r, between blood Pb and Cd levels was 0.631 (p < 0.01) for 132 subjects consisting of cloisonne ware workers and normal subjects. r between blood Pb and blood Cr levels was 0.501 (p < 0.01), and that between blood and urinary Pb levels, 0.794 (p < 0.01). The above assays showed that glaze workers at cloisonne plants suffer severe exposure to lead and slight exposure to Cd and Cr.

Aerobic Capacity of the Brick-field Workersin Eastern India
Satipati CHATTERJEE, Samit Kumar MITRA and Amalendu SAMANTA
Abstract : Forty two male brick-field workers of two age groups, viz. 20-29 and 30-39 yrs were studied with a view to determine their aerobic capacity (VO2max). The average values of VO2max in l.min-1 showed only small change between the young and the aged groups, but the values of the VO2max in ml.kg.-1min-1 showed significant difference between the groups due to body weight increase in the aged group. The aerobic capacity of the workers engaged in heavy manual work such as puddlers and load carriers were found to be comparatively higher and a positive significant relationship has been established between the aerobic capacity and different occupations in the brick-field workers.

Determination of Delta-aminolevulinic Acid in Plasma using High-performance Liquid Chromatography --A Sensitive Indicator of Lead Effects--
Yoko MORITA, Shunichi ARAKI, Tadashi SAKAI, Takaharu ARAKI and Yoshiaki MASUYAMA
Abstract : We developed a simple and reliable method for determining delta-aminolevulinic acid (ALA) in plasma (ALA-P) by fluorometric high-performance liquid chromatography. The method was applicable to 100 mul of plasma and the mean ± standard deviation for analytical recovery was 100.4 ± 2.6% when 50 mug/l of ALA was added to 14 plasma samples. The detection limit for ALA-P was 2.0 mug/l (signal-to-noise ratio was 5) and the standard curve was linear in a wide range up to 400 mug/l. The ALA-P level for 26 unexposed male adults was 8.6 ± 1.3 mug/l. In 72 male lead workers, logarithm of ALA-P concentration was significantly correlated with blood lead concentrations (Pb-B) of 2.5-115.4mug/dl (r = 0.924, p < 0.001). Even at the Pb-B level less than 15mu g/dl, significant linear relationships were found between Pb-B and log ALA-P (r = 0.632, p < 0.01), between Pb-B and delta-aminolevulinic acid dehydratase activity (ALA-D) (r = -0.573, p < 0.05), and between ALA-D and ALA-P (r = -0.765, p < 0.001). It is suggested that ALA-P determined by the present method is a useful indicator of biological effects of lead, especially in the wide range of Pb-B level.

Absence of Mutagenicity in Peripheral Lymphocytes of Workers Occupationally Exposed to Methyl Methacrylate
Kazunori SEIJI, Osamu INOUE, Toshio KAWAI, Kazunori MIZUNUMA, Tomojiro YASUGI, Chan-Seok MOON, Shintaro TAKEDA and Masayuki IKEDA
Abstract : 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.

Occupational Disease Profile in Taiwan, Republic of China
Saou-Hsing LIOU
Abstract : Lack of knowledge of the exact contents of the materials and improper handling of the toxic chemicals lead to the occurrence of occupational illnesses in the developing countries. However, the incidence of occupational diseases was usually underestimated. This article presents the profile of occupational diseases in Taiwan from two sources, i.e. occupational disease benefit payments of labor insurance and the review of relevant literature. The primarily documented occupational diseases in Taiwan were pneumoconioses. The second most common occupational disease was carbon monoxide intoxication, followed by lead poisoning and noise-induced hearing loss. Less than five percent of occupational diseases were due to the other causes, including decompression syndrome, heat stroke, toxic hepatitis, neurological disorders and hematologic disorders. The number of occupational diseases recognized in Taiwan was considered to be seriously underestimated due to the shortage of occupational medical specialists. Priority in the development of occupational medicine in Taiwan is to educate industrial hygienists and physicians to recognize health hazards in the work environment and to diagnose occupational diseases. Recognition of occupational diseases could subsequently highlight the health hazards in the workplace and prevent workers from overexposure.

Fractional Clearances of Low Molecular Weight Proteins in Lead Workers
Yoshitsugu KONISHI, Ginji ENDO, Atsuhiko KIYOTA and Shun'ichi HORIGUCHI
Abstract : Urinary a1-microglobulin (a1-m) and B2-microglobulin (B2-m) can be used as early indicators of renal tubular dysfunction. However, low levels of lead exposure cause an increase in urinary a1-m, but not in urinary B2-m. In order to clarify the level of tubular dysfunction in early lead nephropathy, fractional clearances of a1-m (FC-a1-m) and B2-m (FC-B2-m), i.e., the ratios of these clearances to the creatinine clearance, were measured in 99 male lead workers. Blood urea nitrogen, serum creatinine, uric acid, and urinary creatinine and N-acetyl-B-D-glucosaminidase activity were also measured to diagnose the presence of other renal dysfunction. The median of FC-a1-m was 0.13% in the control group. The FC-a1-m increased in lead workers with blood lead (B-Pb) levels above 20 μg/dl. The correlation of FC-a1-m with urinary a1-m was highly significant, but there was no correlation with serum a1-m. The median of FC-B2-m was 0.065% in the control group. There was a correlation of FC-B2-m with FC-a1-m, but there was no correlation with B-Pb, or with serum B2-m. These results suggest the following: There was a very low excretion rate of a1-m and B2-m in both the control group and the lead exposed groups. The excretion rate of a1-m was higher than that of B2-m. There seemed to be slight a dysfunction of tubular reabsorption in the lead workers, and the elevation of a1-m excretion reflected the dysfunction more sensitively than the elevation of B2-m excretion in lead poisoning.

Age-related Changes in Electrocardiographic Responses to Trichloroethylene Inhalation in Conscious Rats
Heihachiro ARITO, Masaya TAKAHASHI, Hiroshi TSURUTA and Teruyuki ISHIKAWA
Abstract : Age-related effects of trichloroethylene (TRI) inhalation on heart rate (HR), its circadian rhythm, the incidence of spontaneous bradyarrhythmias (BA) and ventricular premature contractions (VPC) were examined in conscious rats, as was the dependence of arrhythmias on sleep-wakefulness. Indwelling electrodes were used for simultaneous electrocardiographic (ECG), electroencephalographic (EEG) and electromyographic (EMG) measurements in 2, 13, 20 and 26-month old rats. The rats were exposed for 8 hours to 300 ppm TRI followed by exposure to clean air for 7 days, after which they were exposed to 1,000 ppm for 8 hours. The polygraphic recordings were made during 8-hr exposures and for 28 hours thereafter. Control values for all physiological parameters were measured during 36-hr exposure to clean air. The exposure to TRI exacerbated an age-dependent decrease in HR and its circadian amplitude. Although the spontaneous BA incidence decreased with advancing age, the ratio of the number of BA episodes during the post-exposure period after TRI exposure to those during the corresponding period of clean-air exposure increased more pronouncedly for 20 and 26-month old rats than for 2 and 13-month old rats. The number of spontaneous VPC episodes increased for 20 and 26-month old rats but was not affected by the exposure to TRI. Gas chromatographic analysis of TRI and free trichloroethanol (TRI-OH) in the brain and blood of the TRI-exposed rats revealed the prolonged half-life of TRI and the delayed clearance of free TRI-OH from the tissues with advancing age. The age-related exacerbation of those ECG responses to TRI inhalation appears to be brought about in part by the age-related change in the pharmacokinetics of TRI and TRI-OH.

Neurochemical Profile of Effects of 28 Neurotoxic Chemicals on the Central Nervous System in Rats (1) Effects of Oral Administration on Brain Contents of Biogenic Amines and Metabolites
Megumi KANADA, Muneyuki MIYAGAWA, Mitsuo SATO, Hiromichi HASEGAWA and Takeshi HONMA
Abstract : We investigated the effects of oral administration of 28 organic chemical agents, all of which possess neurotoxicity and most of which are used as industrial solvents, on monoamine neurotransmitters and metabolites in the rat brain. Each chemical was administered to rats singly at a dose of one-quarter the LD50 value. Two hours after administration, acetylcholine, 3,4-dihydroxyphenylalanine (DOPA), dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), norepinephrine, 3-methoxy-4-hydroxyphenylglycol (MHPG), serotonin, and 5-hydroxyindoleacetic acid (5HIAA) contents in the small-brain regions were measured. Twenty-one of the 28 chemicals increased acetylcholine in the hippocampus, a ratio (21/28) far higher than the 0.5 expected were these chemicals to have no tendency to increase or decrease acetylcholine. This ratio was calculated for each brain substance. Large differences from 0.5 were also obtained for DOPAC (higher), and for 5HIAA and three neurotransmitters (dopamine, norepinephrine, and serotonin) in the hypothalamus (all lower). The ratios for MHPG and 5HIAA in the medulla oblongata were very high. In the hypothalamus, the concentrations of brain substances were easily altered by the test chemicals, and the turnover rates of hypothalamic norepinephrine and serotonin in the medulla oblongata seemed to be accelerated. Several lines of evidence obtained in previous studies suggest that the increased acetylcholine content in the brain homogenate induced by organic solvents such as toluene may be due to a decrease in acetylcholine release from nerve terminals. Based on the results of the present experiment and previous studies, this acetylcholine suppressing property appears to be common to solvents which possess anesthetic properties.

Speciation of Vanadium(IV) and Vanadium(V) Using Ion-exchange Chromatography and ICP-AES
Mitsutoshi TAKAYA and Katsuhiko SAWATARI
Abstract : A speciation method for vanadium(IV) and vanadium(V) is presented that uses a combination of HPLC and ICP-AES. In this method, 1 mM HNO3 solution and 100 mM HNO3 solution were applied in sequence as eluent. A vanadium(IV) and vanadium(V) mixture was injected into a HPLC anion-exchange column; and vanadium(IV) cation was then eluted by 1 mM HNO3, while vanadium(V) oxoacid anion was trapped on the column. After this separation, vanadium(V) was eluted as a cation from the column by 100 mM HNO3. Vanadium was detected by ICP-AES. In this separation, about 15% of vanadium(V) interfered with vanadium(IV), and trace vanadium(IV) interfered with vanadium(V). This interference could be estimated by simple calculation based on standard observations, and the speciation of vanadium(IV) and vanadium(V) was performed. The lower determination limit was 1 μg/mL, which is insufficient to speciate vanadium sampled by conventional sampling methods in a working environment. However, impurity of the other valent vanadium species in a vanadium(V) reagent can be determined by the present method, which should be valuable in precisely assessing the toxicities of vanadium species.

Physical Fitness in Lignite Miners
Petr BRHEL, Pavel HOMOLKA, Jaromira KRATOCHYILOVA and Eva BARTLOVA
Abstract : The purpose of this study was to determine physical fitness level of lignite miners in the Czech Republic. The authors have examined a representative group of 152 active lignite miners by bicycle spiroergometry. The duration of employment in coal mines ranged between 5 and 32 years. The average age was 43.1 ± 4.7 years. The miners had an average peak oxygen consumption 2.9 ± 0.5 l.min-1, corresponding to 99.7 ± 20.4% of the predicted maximal oxygen consumption. Physical fitness of lignite miners was comparable with reference values for healthy men in Czech population. The level of physical fitness did not correlate with the length of exposure to underground work.

The Pattern of Some Lipid Fractions in the Serum of Women Chronically Exposed to Carbon Disulfide
Stainslaw STANOSZ, Dariusz KULIGOWSKI, Ewa ZUK, Dorota RZECHULA, Boguslawa KOSCIUSZKIEWICZ and Dariusz CHLUBEK
Abstract : The present study was performed in 307 women, aged 25 to 55 years (mean 42.7 ± 4.7). The control group included 70 women, aged 42.1 ± 3.5 years, who had previously had no contact with CS2. The study group included 237 women, age 42.9 ± 5.1 years, chronically exposed to 5 to 7 ppm level of CS2, monitored daily using a spectrophotometric method. It was found that quantitative abnormalities in the lipid fractions of blood in women chronically exposed to CS2 appear after the age of 39 years. They were manifested by a significant increase in the serum levels of total cholesterol and LDL-Ch, and a decrease in HDL-Ch. No differences were noted as to the concentration of free fatty acids between both groups.

Assessment of Noise Environment in a Major Railway Station in India
Prabal BANDYOPADHYAY, Sunil Kumar BHATTACHARYA and Shri Kamt KASHYAP
Abstract : To assess the degree of noise pollution in relation to the health and safety of the employees and commuters, a study on the levels of noise originating from various locomotives and also from different other sources was undertaken at Kalupur railway station of Gujarat State in India. The sound pressure levels (SPL) were measured on platforms. Noise dose count was monitored on a ticket collector on duty for 8 h. The results reflected that the SPLs in the platforms well exceeded the day time noise exposure limit. Further, the SPLs produced by loudspeakers were high and those by train whistles were intensely high pitched. The noise dose count of the ticket collector was also in excess of ACGIH standard. All these suggest that the SPLs in the platforms can endanger the healthful living of the users. Suitable control measures have been suggested.

Nuclear Proteins Binding to the Human Metallothionein-IIA Gene Upstream Sequences
Shinji KOIZUMI and Fuminori OTSUKA
Abstract : Metallothionein genes are known to be transcriptionally regulated by a variety of factors such as heavy metals, glucocorticoids and cytokines, and have multiple regulatory elements in their 5'-flanking region. To study the interactions between these sequences and regulatory factors, HeLa cell nuclear proteins were analyzed by band-shift assay using a 95-base pair (bp) DNA probe containing a part of the human MT-IIA gene upstream sequences. Consequently, two Zn-dependent DNA-binding proteins were detected. One of these showed properties almost identical with those of zinc regulatory factor (ZRF), which had been detected using an oligonucleotide probe containing the metal responsive element (MRE); namely, this protein is activated only by Zn, and requires not only MRE but also its flanking sequences for optimal DNA-binding. The other protein appears to be Sp1, based on its recognition sequences specificity. In addition, by South-western blotting analysis of nuclear extracts using the 95-bp probe or MRE oligonucleotide probe, we detected a Zn-dependent DNA-binding protein with a molecular mass of 116 kDa, which is likely to be ZRF. Analysis of HeLa cell nuclear proteins fractionated by glycerol gradient centrifugation showed that ZRF is distinct from another MRE-binding protein, MREBP.

Study of Some Biochemical Changes Among Workers Occupationally Exposed to Phenol, Alone or in Combination with Other Organic Solvents
Magdy Youssef SHAMY, Ragaa Mohammed EL GAZZAR, Mohamed Ahmed EL SAYED and Alaa Morsi ATTIA
Abstract : The present study was aimed for the effects of exposure to multiple organic solvent vapors in comparison with single exposure to phenol. It included 20 workers exposed to phenol alone and 32 workers of combined exposure to phenol, benzene, toluene and methyl ethyl ketone. A control group of 30 subjects was also included. The levels of transaminases, total proteins, prothrombin time, bleeding time, clotting time, fasting blood sugar, serum creatinine and some trace elements (copper, zinc, iron, magnesium, manganese and calcium) were determined in blood together with a complete blood picture. Urine samples were analyzed for phenol, hippuric acid and methyl ethyl ketone. The effects of combined exposure did not differ from that of exposure to phenol alone concerning the majority of the tested parameters. Only the levels of platelets count, prothrombin time, eosinophils, copper and iron have been affected by combined exposure in a probably additive manner.

Assessment of the Mechanical Properties of Peripheral Arteries In Chain Saw Operators Using a Photosensor
Hideki NAKAMURA,Hiroyuki NAKAMURA,Hirofumi NAGASE and Tamotsu MIYOSHI
Abstract : In order to evaluate the severity of peripheral vascular disorders, and to detect changes in the digital arteries of workers who use chain saws, the mechanical properties of the digital arteries of 22 such workers were examined using a photosensor. The elastic properties and the nonlinearity of digital arteries were assessed through observation of the changes in the vasculat volume ratio (V/Vo)against the volume (Vo)at mean blood pressure (Pm). A significant negative correlation was found between age and V/Vo at a transmural pressure of 30 mmHg (V30/Vo), which suggested that V30/Vo tended to decrease with aging. Although it was impossible to calculate V30/Vo for chain saw operators because of the vague changes in the volume pulse wave, this nonlinearity was more clearly observed through changes in the relative vascular volume (V/V40)along with a reduction in cuff pressure (Pc)to 40 mmHg below systolic blood pressure. A group of similarly aged healthy controls and three groups of workers with a different severity of vibration-induced white finger (VWF), i.e., no symptoms of VWF, and severe VWF, were classified according to the changes in their V/V40 and the reduction in Pc. The results obtained in the present study suggest that the peripheral vascular disorders in workers using chain saws are due to the opening disturbance of the arteries with nonlinear changes in the peripheral artery, which is related to functional and organic abnormality of the arteries.

Work Stress and Depressive Symptoms among Japanese Information Systems Managers
Yuko FUJIGAKI, Takashi ASAKURA and Takashi HARATANI
Abstract : The aim of the present study is to investigate the task-specific work stressors of IS (Information Systems) managers and to analyze the effect of these work stressors on depressive symptoms among these managers. A questionnaire including 33 items on work stressor was designed. Three hundreds of samples were gathered. The response-rate was 66.4%. Factor analysis suggested that these 33 items were categorized into 8 factors; job-overload, project-management, mental-rewards, job-latitude, communication with users, career development, technical difficulty, and work-environment. Eight work stressor scores were constructed using this Factor analysis. Using the 8 stressor-scores, and 6 items of background data, multiple regression analysis was conducted on the depressive symptoms score. Depressive symptoms were assessed using the Center for Epidemiologic Studies-Depression (CES-D) scale. The results showed that the factors of project-management, mental-rewards, and job-overload had significant effect on depressive symptoms (p < 0.01). It is indicated for the first time that software project management affects depressive symptoms in systems managers.

Dietary Sources and Background Levels of Hippuric Acid in Urine --Comparison of Philippine and Japanese Levels--
Maria Beatriz G.VILLANUEVA, Hiroshi JONAI, Seiichiro KANNO and Yasuhiro TAKEUCHI
Abstract : Levels of sodium benzoate in processed food from the Philippines and Japan were analyzed by high performance liquid chromatography. Results showed that of the 44 samples from the Philippines, 31 (70%) contained the compound. The samples with sodium benzoate included 19 juice, 6 softdrink and 6 soy sauce varieties. As for the Japanese products, only 8 (26%) out of 31 food items tested positive for sodium benzoate. The values of the compound in the Philippine samples ranged from 20 BBBg/ml to more than 2000 BBBg/ml; the Japanese products showed a range of 50 to 200 BBBg/ml. Background urinary hippuric acid levels in 43 male Filipinos and 34 male Japanese with no occupational exposure to toluene were also measured using a high performance liquid chromatograph. Hippuric acid levels expressed as geometric means (SD) were 0.11 g/g creatinine (0.41) for the Filipino subjects and 0.09 g/g creatinine (0.39) for the Japanese subjects. No statistically significant difference in hippuric acid values in the 2 groups was noted. Possible explanations for the lack of any difference in background urinary hippuric acid levels between Filipino and Japanese subjects were discussed.

Postlabeling Analysis of DNA Adducts in White Blood Cells from Lead Smelter Workers
Masayoshi ICHIBA, Hirotaka OISHI, Yanping WANG, Minako IYADOMI and Katumaro TOMOKUNI
Abstract : We analyzed DNA adducts levels in white blood cells from 14 lead smelter workers for the first time as an indicator of the effect of lead exposure and compared with some lead exposure indices to evaluate whether lead exposure induces DNA adducts significantly. DNA adducts were measured by the nuclease P1 enhanced 32P-postlabeling method. As the lead exposure indices, we chose blood lead (Pb-B), urinary AAA-aminolevulinic acid (ALA) and erythrocyte protoporphyrin (FEP). The levels of DNA adducts had a weak positive correlation with urinary ALA concentration (r=0.62), but not significant correlation with Pb-B and FEP. This result suggests taht lead exposure might have the effect to remain DNA adducts. The inhibition of DNA repair system may be one reason. This preliminary study need be followed by extended survays on lead exposure.