Polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations in serum samples of workers at intermittently burning municipal waste incinerators in Japan.

OBJECTIVES: To find whether or not incinerator workers employed at intermittently burning municipal incineration plants are exposed to high concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). METHODS: 20 Workers employed at three municipal waste incineration plants (incinerator workers) and 20 controls were studied. The previous job, dietary, smoking, and body weight and height were obtained from a questionnaire survey. Concentrations of PCDDs and PCDFs were measured in serum samples of the workers and the deposited dust of the plants. The influence of occupational exposure on concentrations of PCDDs and PCDFs in serum samples was examined by multiple regression analysis. RESULTS: Dust analysis showed that dominant constituents were octachlorodibenzo-p-dioxin (OCDD) and 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD) among the PCDDs, and 1,2,3,4,6,7,8-heptachlorodibenzofuran (HpCDF) and octachlorodibenzofuran (OCDF) among the PCDFs. The toxicity equivalents (TEQs) of summed PCDDs and PCDFs in the deposited dust were 0.91, 33, and 11 ng TEQ/g, respectively, for plants I, II, and III. The means of TEQ in serum samples of summed PCDDs and PCDFs in the incinerator workers and controls were 22.8 and 16.4 pg TEQ/g lipid for area I, 29.4 and 19.3 pg TEQ/g lipid for area II, and 22.8 and 24.9 pg TEQ/g lipid for area III, which were almost the same as for the general population of Japan. No significant differences in the TEQ of PCDDs and TEQ of PCDDs and PCDDs were found between the incinerator workers and the controls. However, the TEQ of PCDFs was significantly higher among the incinerator workers in areas I and II, and the 1,2,3,4,6,7,8-HpCDF concentration was also significantly higher for all three areas. When the occupational exposure index for each constituent of PCDDs and PCDFs was defined as the product of the duration of employment at the incineration plant and the concentration of the constituent in the deposited dust, multiple regression analysis showed that the concentrations of HxCDF, HpCDF, and TEQ of PCDFs in serum samples increased with the occupational exposure index. The multiple regression analysis also suggested that significant factors affecting the concentrations in serum samples were area for HxCDD, age for TCDD, PeCDD, PeCDF, TEQ of PCDDs, TEQ of PCDFs, and TEQ of summed PCDDs and PCDFs, and BMI for HxCDD, HpCDD, and OCDD. CONCLUSION: This study showed that incinerator workers employed at intermittently burning incineration plants were not necessarily exposed to high concentrations of PCDDs and PCDFs. However, the increases in the concentrations in serum of HxCDF, HpCDF and TEQ of PCDFs with the occupational exposure index suggest that the incinerator workers had inhaled dust containing PCDDs and PCDFs during their work.

[An epidemiological study regarding the hearing acuity of residents in the area with high level of aircraft noise: results of hearing tests conducted in the vicinity of Kadena Air Base].

Hearing tests, primary and secondary, were conducted in two communities vicinal to Kadena US Air Base in Okinawa from May 1996 to July 1998. The noise exposure expressed in WECPNL as designated by the Defense Facilities Administration Agency ranged from 85 to 95 and above. A total of 2035 subjects aged between 25 and 69 years inclusive were considered eligible for inclusion in this study and among them 137 males and 206 females underwent the primary test. Before the test, subjects were asked about hearing difficulty, tinnitus, otological anamnesis and past experience of noise exposure at work and/or hobbies. The primary test was a pure tone audiometry using the ascending method of limits with 5 dB step at 7 test frequencies of 0.5 to 8 kHz. Forty individuals who were judged to have possible noise induced hearing loss were sent to Okinawa Chubu Hospital as subjects for the secondary test. The secondary test consisted of pure tone audiometry with 1 dB step at 9 test frequencies with the addition of 3 kHz and 6 kHz to the primary test frequencies, a Short Increment Sensitivity Index (SISI), test, tympanometry and audioscan audiometry. Based on test findings 12 subjects were considered to have noise induced hearing loss. The examiners interviewed the 12 subjects again to confirm that they had not experienced habitual or repeated intense noise exposure other than aircraft noise exposure around their homes. The geographical distribution of the subject's residences showed their proximity to the airfield, which strongly suggests that the cause of hearing loss may be exposure to aircraft noise from Kadena Air Base.

[Evaluation of hearing disorders and social support among the middle aged and elderly in the community. I. Analysis on the relationship between hearing difficulties and social participation, and self-rated health].

OBJECTIVES: To clarify the actual conditions of middle-aged and elderly community residents with hearing disabilities; and to investigate, through self-evaluation, the impact of hearing difficulties on health and social participation so that a key can be found to provide social support for residents with some degree of hearing impairment. METHODS: A questionnaire survey was conducted in Soyo village in Kumamoto Prefecture. The subjects of the survey were 2,199 residents aged 40 years and older receiving health check-ups in accordance with the Health Service Act for the Aged. The questionnaires consisted of 8 items regarding self-evaluations of health, hearing difficulties, the utilization of hearing aids, tinnitus, and social life. RESULTS: Data from 2,075 respondents who completed the questionnaire were analyzed. The results were as follows: 1. The number of residents claiming hearing difficulties according to age: 40 s--1 man (0.6%) 50 s--7 men (3.9%) and 7 women (2.8%) 60 s--26 men (8.3%) and 16 women (4.2%) 70 s(+)--42 men (17.5%) and 37 women (11.1%) The percentage of respondents suffering from hearing difficulties increased significantly with age with percentages higher in men than in women among all age groups. 2. Thirty-eight men and 32 women reported customary use of a hearing aid. Hearing aid use was 0.6% among men in their 40 s, 1.1% in men and 1.2% for women in their 50 s, 3.2% in men and 1.6% for women in their 60 s, 10.4% in men and 6.9% in women in their 70 s or older. 3. Logistic regression analysis showed a significant association between hearing difficulties and social participation (Odds ratio: 1.56; 95% Confidence Interval, 1.02-2.38). The degree of social participation (participation in a variety of activities/communication by telephone) was restricted by hearing difficulties. 4. Logistic regression analysis showed a significant association between hearing difficulties and self-evaluated health (Odds ratio: 2.47; 95% Confidence Interval, 1.38-4.42. The elderly with hering difficulties tended to show lower self-evaluated health. CONCLUSIONS: This study suggests the necessity of creating and implementing social policies that deepen residents' awareness of hearing disabilities as invisible barriers in the home, in the workplace, and in the community; and the necessity of improving the living environment through the utilization of barrier-free designs that will foster better communication.

Polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations in the serum samples of workers at continuously burning municipal waste incinerators in Japan.

OBJECTIVES: To find whether concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in serum increased in workers at municipal incinerators that burn continuously. METHODS: 30 Workers employed at three municipal waste incineration plants (incinerator workers) and 30 control workers were studied. The incinerator workers had worn dust masks or airline masks during the periodic repair work inside the incinerators. Previous job, dietary habit, smoking habit, distance from residence to the incineration plant, and body weight and height were obtained from a questionnaire survey. Concentrations of PCDDs/PCDFs were measured in the serum of the workers and the dust deposited in the plants. The influence of various factors on serum concentrations of PCDDs/PCDFs was examined by multiple regression analysis. RESULTS: Dust analysis showed the greatest amount of octachlorodibenzo-p-dioxin (OCDD), followed by 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD), 1,2,3,4,6,7,8-heptachlorodibenzofuran (HpCDF), and octachlorodibenzofuran (OCDF). The toxicity equivalents (TEQs) of PCDDs and PCDFs in the deposited dust were 4.8, 1.0, and 6.4 ng TEQs/g, respectively, for plants A, B, and C. The mean serum TEQs of PCDDs and PCDFs in the incinerator workers and control workers were 19.2 and 22.9 pg TEQs/g lipid, respectively, for area A, 28.8 and 24.5 pg TEQs/g lipid for area B, and 23.4 and 23.6 pg TEQs/g lipid for area C. No significant differences were found between the incinerator workers and the controls for TEQs of PCDDs and PCDFs separately, and TEQs of PCDDs and PCDFs together. However, the serum 1,2,3,4,6,7,8-HpCDF concentration was significantly higher in the incinerator workers than in the controls for all the three areas. When the exposure index to 1,2,3,4,6,7,8-HpCDF is defined as the product of the concentration of 1,2,3,4,6,7,8-HpCDF in the deposited dust and duration of employment, the concentration of 1,2,3,4,6,7,8-HpCDF in serum increased as the exposure index increased. Multivariate analysis suggested that the serum concentration of HpCDF increased with duration of employment at the incineration plants and OCDF increased with employment of > or = 21 years. The other significant variables (p < 0.01 or p < 0.001) were area for hexachlorodibenzo-p-dioxin (HxCDD) and tetrachlorodibenzofuran (TCDF), Brinkman index for HpCDD, and body mass index (BMI) for tetrachlorodibenzo-p-dioxin (TCDD), HpCDD, and TEQs of PCDDs. CONCLUSION: The serum TEQs of PCDDs and PCDFs was not significantly higher among the incinerator workers, but the serum concentration of 1,2,3,4,6,7,8-HpCDF was. This suggests that the incinerator workers had inhaled dust containing PCDDs and PCDFs while working in plants equipped with incinerators that burn continuously.

[A Japanese language version of the health-promoting lifestyle profile].

The development and initial psychometric evaluation of a Japanese version of the Health-Promoting Lifestyle Profile II (HPLP II) is described. The 52-item instrument was translated into Japanese and was found to be culturally relevant and reliable in a pilot study. The Japanese version was then administered to adiverse but predominantly Japanese group of 337 subjects residing in northern Japan. The Japanese version of the HPLP II was evaluated using factor analysis and reliability measurement. Six factors similar to those isolated previously during psychometric assessment of the English language version were extracted. Those six dimensions comprise the HPLP II subscales of: 1. Health responsibility, 2. Spiritual growth, 3. Physical activity, 4. Interpersonal relations, 5. Nutrition, and 6. Stress management. The alpha reliability coefficient for the total scale was 0.94 and the 2-week retest reliability was 0.91; the alpha coefficients for the subscales ranged from 0.70 to 0.87. The Japanese language version of the HPLP II appears to have sufficient validity and reliability for use by researchers who wish to describe the health-promoting components of lifestyle among the Japanese population and to explore differences and similarities in the health-promoting lifestyle of Japanese and American subjects or those of other ethnic groups. Further evaluations of measurement with different populations appears warranted. This instrument will enable researchers to investigate patterns and determinants of health-promoting lifestyle, as well as the effects of interventions to alter the lifestyle.

Community-based analysis of the factorial structures of the recent increase in low birthweight infants.

This study was conducted to determine whether the regional factors were related to the increase in the percentage of low birthweight (LBW: <2,500g) infants in Kumamoto Pref., and to establish a tentative structure model for predicting low birthweight infants. Analyses for frequency of LBW infants between 1974 and 1997, and a multiple regression model and covariance structure model were conducted using data from the vital statistics between 1992 and 1997 and regional indicators concerned with LBW infants from official registered statistical data between 1992 and 1997. The 72 regional factors were clustered into four groups linked with agricultural areas such as Urban, Flat, Hilly and Mountainous areas. The recent increase in the incidence of LBW infants resulted from the increase in moderate-LBW (MLBW: 2,000-2,500 g) infants of full term-LBW infants. There was a steady annual increase in the Urban agricultural area LBW infants since 1992. The two structure analyses revealed that the Urban area had a marked effect on the increase in LBW infants, whereas, farm villages in Hilly or Moutainous areas had less effect on the increase in LBW infants. These findings suggest that the regional factors relating to the mothers' life-style or regional environments play a key role in the etiology and prevention of LBW, and will be a useful in the analyses using official registered material.

Determinants of life satisfaction among Japanese agricultural workers.

The purpose of this study was to investigate the factorial structure of life satisfaction in agricultural workers. One hundred and sixty-five (87 males and 78 females) agricultural workers mainly engaged in plastic greenhouse cultivation in southern Japan, ranging in age from 19 to 72 years (mean = 44.3 years), completed a questionnaire. Scores of life satisfaction showed a higher tendency in males than in females, and those in elders were higher than in younger people. Conversely, females showed higher stress scores than males, and younger people's score were higher than the elders. Multiple regression analysis was performed to analyze the factorial structure of satisfaction. It is suggested that the level of life satisfaction is positively related to social support, and is negatively related to the impact of stressful life events, globally perceived stress and subjective symptoms of ill health. Stress levels depended on factors concerning the psychological demands of work, work posture, work hours and work environment. Different factorial structures were observed between female and male workers. Findings from this study suggest that a strong social support network may assist in enhancing life satisfaction. Furthermore, the ill health and stress experienced in agricultural work were associated with a reduced life satisfaction.

[An analysis on a relationship between perinatal mortality and live births of low birthweight, in Kumamoto Prefecture, 1968-1994].

The aims of this investigation were to describe the relationship between perinatal mortality rates and the proportions of live births among low birth weight (LBW) infants from 1968 to 1994, and to determine risk factors in infants of low birth weight. Using vital statistics from 1968 to 1994 of the Japanese government and the Kumamoto Prefecture and Maternal and Child Health Statistics of Japan from 1968 to 1995, perinatal deaths and live births of infants of low birth weight were studied according to national statistics criteria. In Japanese and Kumamoto Prefecture, there was an association between perinatal deaths and live births of LBW. The significant decline of perinatal mortality rates from 1968 to 1976, of which the fetal death ratio at 28 weeks and over mostly declined, was closely related to the decline of live births of LBW. In this period, the improvement of socioeconomic conditions and the comprehensive health care provided by the government contributed in improving perinatal mortality rates. From 1977 to 1988, the annual variation of Kumamoto was different from that of all Japan. Both perinatal mortality rates continued to decline due to a general decrease in early neonatal mortality rates. The number of Live births of LBW infants in Kumamoto prefecture increased in 1977 and once again started to decline in 1982. In 1977, the insufficient maternal-child health care and the increase of female workers contributed to increasing rates of live births of LBW. Advances in neonatal medicine contributed to the increase in survival rates of infants of LBW. Although, after 1982, the improvement of maternal-child health care and the perinatal care system contributed to the declining rates of live births of LBW. On the other hand, those rates in all Japan continued to gradually increase from 1977 to 1988. After 1989, perinatal mortality rates continued to decline, and live births of LBW continued to increase in both Kumamoto prefecture and all Japan. These results were contrary to the above results from 1968 to 1976. It was considered that medical advances in the care of pregnant women and neonates increased survival rates of the LBW. In future, the perinatal mortality rates will appear to approach a minimum constant, that is, a minimum of fetal death rates. It is important to reduce the number of LBW infants, particularly birthweight of 2000 g-2499 g, with maternal-child health care.

[Survey of noise exposure level of national forestry workers].

Eighty-one national forestry workers who were using chain saws, log cutters, log cutting machines, bush cleaners, timber-collecting cable machines and forklifts were examined for their level of noise exposure in a working day by using a portable sound meter. And their noise exposure levels Leq (8 h) for a year were estimated based on the measured noise levels and on the number of noise exposure days and hours in a year recorded in their work documents. The survey was made from July to December, 1988. The maximum noise levels with all the machines except a case of the forklift were above 100 dB, and with most chain saws they were above 110 dB. The amount of time that workers were exposed to the noise of logging and lumbering with chain saws, cutting by bush cleaners and timber-collecting cable machines without a cabin was longer than the allowable time for 90 dB and 95 dB. The number of noise exposure days in a year is fewer than reported in the past. The estimated Leq (8 h) for 32 out of 34 lumbermen surveyed was more than 85 dB, and for 5 lumbermen the Leq (8 h) was more than 90 dB. From these results, it can be concluded that there is a danger of noise induced hearing loss in national forestry workers using chain saws, log cutters, log cutting machines and timber-collecting cable machines without a cabin in 1987.

Whole-body vibration and health effects in the agricultural machinery drivers.

Recently farm mechanization has been widespread and developing rapidly, in particular riding farm machines are increasingly used in paddy fields in Japan. We have no information available on the actual situation regarding whole-body vibration on the seats of these farm machines from the standpoint of labour protection. Measurement and evaluation of whole-body vibration was performed on the seats of popular riding agricultural machineries. Whole-body vibration on the seats of combine harvesters and wheel tractors exceeded exposure limits and the fatigue-decreased proficiency boundary limit of 8 hr and also shortened the reduced comfort boundary limits of ISO 2631 (1985). Some combines, tractors and carieers had only less than one hour exposure duration as compared with the ISO 2631-1 standard (1997). On the other hand a questionnaire was also performed on the subject of agricultural machine operators. Any specific injury or other effects, i.e. low back injuries were not found among the group of operators as compared with those in non-operator farmers. It seems to be difficult to find out the health effects of whole-body vibration itself, because there may be a lot of causes, i.e. working posture, operating heavy materials, in farm working conditions.

An experimental study on changes in finger blood pressure during chain-saw operation.

In this study finger blood pressure was observed by using a new method to determine if vasoconstriction activated by sympathetic nervous system takes part in changes in peripheral circulation with exposure to vibration, noise and tool weight. Finger blood pressure was measured every one minute by ambulatory monitoring system. The time profile of a single experiment consisted of 5 minutes pre-exposure period followed by one exposure period lasting 2 minutes and a post exposure period of 5 minutes. Measurement was carried out as a factorial experiment of combination of vibration (17.8 m/s2 in X-axis, 20.0 m/s2 in Y-axis and 50 m/s2 in Z-axis), noise (105 dBA) and tool weight (7.9 kg). Finger blood pressure increased significantly under the following conditions: vibration + noise + tool weight > vibration + noise .=. vibration .=. tool weight > noise .=. control. During exposure period the combination with vibration, noise and finger grip exercise induced 29.7 mmHg of increases on average in finger blood pressure. On the other hand, finger blood pressure was increased 9.5 mmHg by vibration alone. These results agreed with our previous studies which observed the decreases of finger skin temperature and finger blood flow during the same conditions. The present study suggests that possible activation of the sympathetic nervous system may be involved in the physiological mechanisms of the changes in blood flow during chain-saw operation.

[Work history, health conditions and hearing loss of Ishigaki fishermen].

Based on our previous health survey among Ishigaki fishermen in 1979, this study aimed at clarifying the relations of their work histories to physical characteristics, physiological functions, blood conditions and hearing levels. Medical examination was conducted in 1987 on 118 fishermen inclusive of 33 followed-up fishermen, and in 1989 noise-level and noise-induced temporary threshold shift of hearing was measured for different fishing methods. The results were as follows; 1) Fishing history was not specifically associated with any physical characteristics. 2) High HDL cholesterol, which was observed among divers using diving apparatus, was considered to be a survival effect for divers, since HDL cholesterol is amplified by intensive muscle work. 3) Abnormalities of ECG except for a high R wave were notably observed among the divers, who once changed from unassisted diving to diving with apparatus and then to fishing lines. The main reason for switching jobs was claimed to be caisson disease, and it was suggested that diving with apparatus was related to a high risk of health hazards in the central nervous system and/or respiro-circulatory system. 4) Acoustic acuity greatly declined with aging, and which was commonly observed in groups with different work histories. By way of explanation, exposure to ship engine sounds during daily travelling was the most likely cause. It was also revealed that several hours' exposure to the engine sounds was needed to detect a temporary threshold shift of hearing before and after work.

Effect of low level acoustic stimulation on temporary threshold shift in young humans.

To assess the effect of a low level acoustic stimulation on the susceptibility to noise, young human subjects were exposed to music at 70 dBA for 6 h per day during 9 days (training period). Noise sensitivity was assessed by measuring temporary threshold shift (TTS) induced by 105 dBSPL, 1/3 octave band noise at 2 kHz for 10 min. On the fifth day of the training period, a significant decrease of TTS was observed in the frequency range 3-3.5 kHz, in comparison with the baseline TTS obtained before being trained. As the training continued, the frequency range which showed a significant reduction of TTS expanded to 2-5 kHz.

[An epidemiological study on low back pain and occupational risk factors among clinical nurses].

Recently medical services and nursing system are being reformed due to high medical costs and shortage of clinical nurses. The shortage of clinical nurses influences not only their working conditions but also their own health problems. In European countries and the United States, low back pain (LBP) has been reported to be one of the most common and costly health problems among clinical nurses. To estimate the occupational risk factors of LBP among nurses, a questionnaire survey of LBP and occupational risk factors was carried out in 1987 on 947 clinical nurses and as well as on 300 female clerical workers of three local governments. First, to examine the prevalence and the magnitude of the problem, we analyzed several kinds of prevalence rates of LBP and its characteristics among nurses and clerical workers. Second, a case-control study was conducted to investigate the relationship between LBP and occupational risk factors. In analyzing occupational risk factors of LBP, odds ratios, age adjusted odds ratios and 95% confidence intervals were computed. Finally, to estimate simultaneously the effect of multiple risk factors of LBP and to confirm univariate age adjusted odds ratio analyses, several multivariate analyses were performed. Point, period (a month), and lifetime prevalence rates of LBP and prevalence rate of severe LBP among clinical nurses were significantly higher than those of clerical workers (p less than 0.05-0.001, respectively). Demographic and occupational items, such as being an assistant nurse (as opposed to a registered nurse), and working in certain departments (internal medicine, orthopedic surgery, neurosurgery, psychiatry, tuberculosis ward) showed significantly higher odds ratios for LBP (p less than 0.05-0.001, for all). Many items pertaining to working conditions connected with shift work, hospitalized conditions of patients, taking breaks and holidays, working postures, weight of patients and equipment lifting and moving, working environments and so on had significantly elevated age adjusted odds ratios (p less than 0.05-0.001, for all). Intensity of work loads estimated subjectively such as 'caring for patients who are in bed', 'supporting patients when transporting and bathing them', 'preparing drugs and injections, and treating', 'observing and monitoring patients' conditions', 'instructing and explaining procedure to patients and their family' and so on also had significantly elevated age adjusted odds ratios (p less than 0.05-0.001, for all). Moreover, many items on the problems connected with working life and interpersonal relationships showed significantly higher age adjusted odds ratios (p less than 0.05-0.001). In multivariate analyses, independent variables which made a significant contribution to the model were similar to the items which had significantly elevated age adjusted odds ratios.(ABSTRACT TRUNCATED AT 400 WORDS)

Hand-arm vibration, noise, temperature and static load--an experimental study of peripheral circulation while operating chain-saws.

From the viewpoint of elucidating the etiological mechanism of vibration-induced white finger (VWF), a model experiment was designed using a chain-saw under laboratory conditions. Finger skin temperature and finger blood flow were measured simultaneously as indicators of peripheral circulatory movement, using a thermister and an apparatus for measuring tissue blood flow based on the thermal diffusion method. In the first project (Experiment A), five healthy subjects operated a chain-saw at a high working speed with-out actually cutting anything. In the second project (Experiment B), seven healthy subjects were exposed to three different kinds of experiments with combinations of hand-arm vibration, noise and tool weight at about 15 degrees C room temperature. In the third project (Experiment C), the effects of tool weight and grip force were examined. In the fourth project (Experiment D), patients suffering from vibration disease were exposed to hand-arm vibration and the noise of a chain-saw for 2 minutes. In experiment A, the mean value of the normalized finger skin temperature decreased gradually with cyclic changes corresponding to each exposure and break period. Changes in finger blood flow had almost the same pattern as the changes of skin temperature, but the recovery of blood flow during a 30 sec break period was notable and a slight elevation of the base line was observed. In experiment B, the mean value for the normalized finger skin temperature decreased much more when the subjects operated a chain-saw at a high working speed than when they operated the chain-saw with the noise isolated by double hearing protection. On the other hand, the results obtained in experiment C indicated that the effect of tool weight should be considered as an important factor for investigating the acute changes in peripheral circulation. In experiment D, some patients showed an unusual pattern in the change of blood flow during a post exposure period which was not seen in healthy subjects.

[Midluteal progesterone/estradiol ratio as an indicator of pregnancy potential].

In an effort to determine the reliability of the midluteal progesterone(P)/estradiol(E2) ratio as an index of the potential for conception, we measured the midluteal P and E2 levels in 76 infertile women who had been treated at our infertility clinic. This parameter in conception cycles was compared with that in non-conception cycles. Eighty cycles of the 76 women were classified into two groups, depending upon whether pregnancy occurred or not. Group 1 and group 2 were composed of 31 conception cycles and 49 drug-induced cycles, respectively. Midluteal concentrations of P and E2 did not show any significant differences between the two groups. The P/E2 ratios were 106.4 +/- 71.3 (mean +/- SD) and 71.5 +/- 44.16, respectively. This difference was statistically significant (p less than 0.05). Discriminant function analysis showed that the smallest probability of misclassification between the two groups decreased from 44% when using P only to 36% when using the combined P and E2. The following equation: Y = 0.0727X1 - 0.00456X2 - 0.130 was obtained (when X1 = P, X2 = E2). These results suggest that the midluteal P/E2 ratio gives clinicians the best indication of luteal function for the achievement of pregnancy.

[Effects of ethyl alcohol ingestion on the disturbance of porphyrin metabolism by lead].

A study was made on the possibility of synergistic effects of ethyl alcohol and lead on porphyrin metabolism in rabbits. Experimental rabbits were divided into 4 groups. Group A was the control group not given any treatment, and the other 3 groups (Groups B, C and D) were treated with ethyl alcohol, lead, and ethyl alcohol and lead respectively, for 2 months. Ethyl alcohol solution (5%) was administered to rabbits in Groups B and D as drinking water on every weekday. The average dose of alcohol was 6 ml/kg/day (18 ml/cap/day). Lead was injected intravenously to rabbits in Groups C and D at a dose of 0.5 mg Pb/kg on alternate days (3 times per week). Furthermore, a large dose of Pb was administered to other rabbits (Group C'). In rabbits treated with alcohol alone (Group B), no effect was observed in the biochemical indicators related to porphyrin metabolism. In the groups treated with lead (Groups C and C') and with lead and alcohol combined (Group D), some biochemical changes in porphyrin metabolism developed with increase of Pb-B, i.e. increase of ALA-S activity and total porphyrin content in the bone marrow, elevation of FEP level, increase of ALA-U and CP-U, and decrease of ALA-D activity in erythrocytes. Comparison of Groups C and D showed that CP-U and ALA-U increased significantly in Group D, but no significant difference was observed between both groups in FEP and in ALA-S activity in the bone marrow and liver. The other laboratory measurements, such as total porphyrin contents in the liver and plasma, and GOT or GPT level in serum, showed no significant change in all the groups. In the present study, the biochemical changes suggesting synergism of lead and ethyl alcohol were observed slightly in ALA-U and CP-U but not in ALA-S and FEP. These results suggest that these changes are essentially due to lead rather than mutual enhancement of the direct effects of these two toxins on porphyrin metabolism. However, it still remains to be determined whether or not ethyl alcohol affects the liver and kidney functions which may be related to ALA and CP excretion.

Noise-induced hearing loss in relation to vibration-induced white finger in chain-saw workers.

From the viewpoint of the etiologies of noise-induced permanent threshold shift (NIPTS) and vibration-induced white finger (VWF), the association between VWF and hearing loss was examined among 499 chain-saw workers who underwent a compulsory health examination for vibration syndrome. They were classified by age, duration of noise and vibration exposure, and the severity of VWF. The severity of VWF was evaluated according to the following criteria: no prior history; VWF history, but symptoms had disappeared; VWF present but appearing rarely; frequent appearance of VWF (more than 20 times per winter season). In three age groups (ie, 40-49, 50-59, 60-69 years) with 5-9 years of exposure, the chainsaw workers with VWF had a significantly greater hearing loss at higher frequencies than those without VWF. However, in the 10- to 14-year exposure groups, a significant difference was not found between the VWF and non-VWF groups, except that the 50- to 59-year age groups showed a significant difference in mean age. It was suggested that interindividual differences in susceptibility to noise and vibration may be the reason for the synergistic effects of noise and vibration.