[Significance of mercury analysis in clinical tests].
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Chromatography, Gas↗
Biomedical subjects
M Futatsuka
Publications and source records attributed to M Futatsuka.
An experimental study of the physiological effects of chain saw operation.
This experimental study was designed to determine whether a combination of noise and vibration produced more pronounced changes in temporary shifts of finger skin temperature and temporary threshold shift (TTS) of hearing than those resulting from exposure to either stress alone. Nineteen healthy subjects were exposed to six different combinations of vibration, noise, and handle holding by using a chain saw for a pre-determined time. The mean value of normalised finger skin temperature decreased much more when the subjects operated a chain saw at high speed (exposure 1) than when they operated the chain saw with the noise isolated by double hearing protection (exposure 2). In five of the 14 subjects significantly larger TTS values at 4 kHz were observed in the former condition (exposure 1) compared with the values obtained when they stood beside someone else operating a chain saw (exposure 3). The results of this study suggest that noise may play a part in inducing the constriction of the peripheral vessels seen with local exposure to vibration, and that hand-arm vibration may produce an additive effect on the noise induced TTS.
Adult↗
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.
Adult↗
A case-control study on the prognosis of vibration syndrome.
A case-control study was undertaken to evaluate some factors affecting the prognosis of vibration-induced white finger (VWF), 286 workers, who had used a chain saw in forests and had showed some symptoms and signs that were suspected to be vibration syndrome during some of the years from 1956 to 1980, were selected by medical examinations from a total of 612 forestry workers, and were divided into four groups according to the prognosis of the VWF based on a twenty-year follow-up. The study shows an association between the prognosis of VWF and vibration components, particularly vibration levels, severity of the syndromes not only in peripheral circulation but also in peripheral neuropathy before exposure to vibration ceased. There are also significant associations between the prognosis of peripheral neuromuscular symptoms and the factors of aging and duration of exposure. The study suggests that smoking habits and history of heart failure and diabetes had no effect on the prognosis of VWF.
Finger Injuries↗
Methylmercury exposure and mortality in southern Japan: a close look at causes of death.
This study examines mortality patterns by cause of death to investigate the effect of exposure to methylmercury in a small area of Minamata City (Kumamoto Prefecture, Japan), which has the highest concentration of patients with Minamata disease. Standardised mortality ratios (SMRs) are computed by cause of death for the study area, using the age specific rates of the entire city as a standard. The SMRs for liver cancer and chronic liver disease in the study area are significantly higher than unity and are consistent with the mortality patterns of registered Minamata disease patients. While an excess mortality is observed for cerebral haemorrhage, mortality from cerebral infarction and other cerebrovascular diseases is considerably lower in the study area. The multiple risk factors of liver related diseases and a possible explanation for the cerebrovascular mortality patterns are discussed to suggest further investigation.
Female↗
Pathological changes observed in the finger biopsy of patients with vibration-induced white finger.
Lesion biopsies of 60 fingers from 30 patients with vibration-induced white finger (VWF) and control observations from seven fingers of five referents demonstrated three main characteristic pathological changes. First, in each case, the muscular layers of the arteries revealed intense thickening with strong hypertrophy of individual muscle cells without intimal fibrosis. Periarterial fibrosis was also noted. Arteriosclerosis with foamy cells, lipid deposition, and fibrous sclerosis was occasionally observed. The second main change was demyelinating neuropathy in the peripheral nerves in which a marked loss of nerve fibers had occurred. There was also an increase in the number of Schwann cells and fibroblasts with strong collagen formation. Severe loss of myelin sheath frequently occurred, and relatively smaller axons without myelin which appeared to have regenerated were observed. Perineural fibrosis was also noted. In the third main pathological change connective tissues with collagen were increased not only in the perivascular and perineural lesions, but also abundantly in the corium of the skin. The elastic fibers there had been destroyed. These three principal pathological changes are very useful for the histopathological diagnosis of VWF.
Adult↗
Mortality and survival for Minamata disease.
Analysis of mortality of 439 deaths that occurred among 1483 patients with Minamata disease (MD) in Kumamoto Prefecture, Japan was performed from the end of 1981. Causes of death and survival rates were studied by means of the standardized mortality ratio (SMR) and life-table technique. Of the 439 deaths (29.6%) in MD cases, the first death occurred in 1954. There was a first peak incidence in 1956 when MD was initially reported, however, the majority of deaths occurred after 1972 when a second and much larger peak was evident. In 1970 an important milestone occurred when the Public Nuisance Relief Law (an anti-pollution law) was enacted. Among its provisions, this law required and enabled verification of MD among people suspected of having been exposed. In contrast to the early cases, later cases of MD were older and their mean age-at-death was not different from that of the general population. The mortality rate for all causes of death was significantly higher in both sexes compared to the general population. Significantly lower survival rates were noted for older patients. The cause-specific mortality rates also showed significantly increased SMRs for liver diseases and nephritis-nephrosis-nephrotic syndrome in male patients, and for nephritis-nephrosis-nephrotic syndrome and other diseases in females. On the other hand, the SMR for senility without mention of psychosis was significantly lower than expected in both sexes.
Actuarial Analysis↗
Comparative study of vibration disease among operators of vibrating tools by factor analysis.
Principal component analysis was carried out to determine the interrelationships between subjective symptoms experienced by workers using various types of vibrating tools (brush saws (41), rock drills (39), chipping hammers (42) and chain saws (49)) and control groups (clerks (44), farmers (42)). The characteristics of the patterns of common factors extracted from these symptoms and the frequency distribution of the factor score of the main principal components were compared among the groups. From a wide variety of symptoms, a principal component related to peripheral nerves, muscles, and joints and a component related to peripheral circulation were extracted specifically and separately. The complaints of rock drillers reflected peripheral circulatory factor and those of chain saw users presented a complex factor of nerve muscle, and joints.
Adult↗
Follow up study of vibration induced white finger in chain saw operators.
The current status of subjects with vibration induced white finger (VWF) was observed in order to follow up the natural course of VWF after the use of chain saws had ceased. The prevalence rate of VWF after the use of chain saws had ceased in all time periods fell to 50.2% after more than 12 years' observation. There was a pronounced tendency for the percentage prevalence to rise as the vibration exposure periods after VWF occurred increased, and a similar pattern was observed concerning the exposure periods before VWF occurred. Numbness of hands and arms takes longer to recover than VWF.
Adult↗
[An epidemiological study of diabetes mellitus in the coastal area of the Yatsushiro Sea--sequential changes in the epidemiological characteristics of the disease].
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Adult↗
A multiple regression analysis of hemoglobin values and iron status in Japanese farmers.
The authors performed multiple regression analysis of hemoglobin values and the parameters related to iron dynamics. The subjects consisted of 37 farmers whose Hb, Ht, GB, SI, %-St, SFR and FEP was examined once a month for one year. 19.2% of the female farmers had anemia of which 73.8% was iron-deficiency anemia, 13.7% being latent iron deficiency. Hb, GB and FEP in males and SI, %-St, SFR, FEP in females revealed clear seasonal variations. Multiple correlation coefficient between Hb and SI, %-St, SFR, FEP as independent variables was significant in females but not in males, and the ratio of contribution (38.7%) was not very high, however, the multiple correlation coefficient was significantly high (0.622). Standard regression coefficients between Hb and SFR, FEP were significantly high (p less than 0.01). When Ht and GB were added to these 4 variables, multiple correlation coefficients (male, 0.906; female, 0.957) were remarkably high, which means serum-related variables such as Ht and GB have an undeniably important role as explanatory variables of hemoglobin levels. These standard regression coefficients showed seasonal changes.
Adult↗
Vibration exposure and vibration-induced white finger due to chain saw operation.
A longitudinal study was undertaken to evaluate changes in the prevalence of vibration-induced white finger (VWF) during the period 1956 to 1980 among a population of Japanese state forestry workers. The vibration levels in the measurements occasionally exceeded the 30-minute line proposed by the Draft International Standard ISO/DIS 5349 in one-third octave bands mainly centered on 160 Hz, with 500 Hz in vertical, 400 Hz in sideways, and 250 Hz in back-and-forth sawing operations. The peak prevalence rate was 62.6%, found in the cohort beginning in 1958-1959. Beginning with the 1968-1969 cohort, the prevalence decreased significantly. During the study period, prevalence rates were approximately 10%, 15%, 20%, 25%, 30%, 35%, and 40% after 2, 3, 4, 5, 7, 9, and 12 years of exposure, respectively. The incidence rate increased gradually after 1960 and the peak value was reached in 1966. The peak value of the incidence rate by duration of exposure was about the same (8% to 10%) in the 1958, 1962, and 1966 cohorts; however, in later groups, the incidence rate decreased in the earlier stages of the exposure periods. The latent interval for the development of VWF was 6.4 +/- 3.7 years (6,000 to 7,000 hours) on average, with a 90% range of one to 14 years (700 to 16,000 hours). Of 452 study subjects with VWF (prevalence rate, 33.5%), 13.5% recovered within the exposure periods, 12.2% recovered within one year after the cessation of exposure, and 74.3% still had VWF more than two years after exposure had ended.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Causes of death in Minamata disease: analysis of death certificates.
The causes of death in Minamata disease were analyzed and compared with those of control subjects. Of the 1422 Minamata disease patients in the Kumamoto Prefecture, 378 had died by the end of 1980. Of these 378, the first death occurred in 1954 with a peak incidence in 1956 when Minamata disease was officially reported for the first time. The number of deaths increased rapidly after 1972 with a second peak in 1976. The male:female ratio was 1.8:1 and the mean age-at-death was 67.2 years (SD = +/- 18.65). The mean age-at-death was younger in the cases of the initial outbreak than in those recently. There were, on the average, 2.8 causes of death per person. Of these cases, 157 (41.5%) had Minamata disease indicated on the death certificate, though 64 (16.9%) had Minamata disease coded as the underlying cause. Minamata disease and the noninflammatory diseases of the central nervous system (CNS) were the main underlying causes of death between 1954 and 1969, while, in the multiple cause data, pneumonia and non-ischemic heart disease were the most prevalent. Cerebrovascular diseases (18.0%) were the main underlying causes of death followed by malignant neoplasms (14.7%), cardiovascular diseases (14.1%) and Minamata disease (14.1%) in 1970 or later, while cardiovascular diseases (18.6%), Minamata disease (14.5%), cerebrovascular diseases (10.4%) and malignant neoplasms (7.1%) were the major multiple causes of death. As compared with the control, the proportions of deaths due to noninflammatory diseases of CNS and pneumonia were higher in the initial outbreak. Although the difference in the causes of death was less apparent recently, malignant neoplasms and hypertensive diseases tended to be lower. These results suggest that there is a need for a long-term follow-up of Minamata disease patients. The data also show the potential value of multiple causes of death coding in analyses of mortality.
Adolescent↗
Preliminary evaluation of dose-effect relationships for vibration induced white finger in Japan.
Habitual use of many vibrating tools has been found to be connected with the appearance of various disorders affecting the blood vessels, nerves, bones, joints, muscles or connective tissues of the hand and forearm. The vibration exposures required to cause these diseases are not known exactly, either with respect to vibration intensity and the vibration frequency spectrum, or with respect to daily exposure time and total exposure period. The purpose of this study is to investigate available data on the physical conditions in Japan that have caused vibration induced white finger (VWF) and attempt to establish approximate relationships between vibration conditions and prevalence of VWF. The vibration conditions were evaluated using the method of vibration assessment recommended by the International Standardized Organization, which uses the weighted vibration level of the frequency weighted, dominant, single axis component of vibration directed into the hand. A clear correlation between level, prevalence of VWF and exposure period can be found. The results also suggest the relationship between the weighted levels and latent intervals. These dose-effect relationships enable the prediction of the average latent interval for a population group and the range of progression of the disorders--all from a measurement of the vibration entering the hands. In Japanese cases, 4, 8, and 15% of VWF prevalence correspond with 10, 20, and 40% of VWF prevalence in the Draft International Standard ISO/DIS 5349 (1982) within the weighted vibration level range of 2 to 50m X s-2.
Adult↗
Epidemiological studies of vibration disease due to brush saw operation.
A longitudinal study was performed to evaluate the risk for vibration disease during the period 1961-1980 among a given population of forest workers using brush saws in Japan. The vibration levels in the measurements occasionally exceeded the 60-min line proposed by the ISO/DIS 5349 in 1/3 octave bands mainly centered on 125 Hz in vertical during the sawing operations. The peak prevalence rate was 12.0% found in the cohort group beginning in 1961-1962. Thereafter, it decreased significantly and no patients with VWF were found in the cohort group beginning in 1969-1970. In the study periods, the prevalence rate was around 2, 4, 6 and 7% after 3, 7, 11 and 13 years of exposure time respectively. The incidence rate had two peaks of 2.2% in 1965 and in 1973. Among workers using brush saws, the prevalence rate and incidence rate were smaller than those of workers using various other kinds of vibrating tools. The workers used brush saws for 4 to 5 months a year during the warmer season for grass trimming and limbing. This is the main reason why the prevalence rate was so low in spite of the high acceleration levels of the brush saw. On the other hand, the latency period (6.4 +/- 3.5 years) was rather shorter than that of the chain saw. This result suggests that the individual susceptibility of workers to contract VWF may play a more important role in the case.
Adult↗
Hemoglobin values in adult women of various occupational groups in the community.
In 1966 and 1971, the authors studied hemoglobin values of about 2,000 women of 10 different occupational groups and different social classes in the same district. The mean values of hemoglobin and serum iron were highest in nursing students followed by urban housewives and nutritionists and lowest in 3 groups of farm wives and shoe factory laborers. The difference in the mean values of hemoglobin observed among occupational groups was in principle assumed to be due to the difference of frequency in levels of 11-12 g/dl. Hemoglobin levels between 1966 and 1971 tended to improve as a whole and the differences among occupational groups have been reduced. In this study, some kinds of social conditions as well as some physiological factors related to hemoglobin values were investigated. In the same occupational group, unmarried women had a higher level of hemoglobin than married women. Further, married women with infants showed a relatively lower level than those with no infants. This suggests that hemoglobin values of female workers may be significantly influenced not only by work conditions but also by social conditions including family circumstances.
Adult↗
A follow-up study on the lung disorders of rush (igusa) farmers exposed to "sendo" dust.
In the process of "tatami" mat production, from cultivating to weaving, rush farmers are exposed to "sendo" (dyer's earth) dust using it to prevent fading of the "tatami" mat color. It has been found that the workers tend to develop a relatively early stage of pneumoconiosis after about 20 years of this work. In 1980, 51 male (58.6 years old) and 37 female (54.4 years old) rush farmers, some of whom were previously examined in 1970, were re-examined for lung disorders. Chest X rays in the 1980 showed, 49.0% of males and 62.2% of females over 1/0 according to the 12 point profusion scale with irregular small opacities being dominant, a significant increase in the prevalence rates of pneumoconiosis compared with 1970 values (p less than 0.01 for both males and females). A relatively high prevalence of respiratory complaints and/or lung function impairment was also found. However, there were no severe cases and no significant changes were seen to have occurred during the seventies by those tests. It was also observed that increases in lung disorders during the decade were more common in the female workers. These findings suggest that the pathogenesis of rush farmer's pneumoconiosis might be in the histological changes of bronchial and/or alveolar walls by the deposition of "sendo" dust. The present study revealed that the lung disorders in the rush farmers may be associated with long-term inhalation of "sendo" dust, and the introduction of more suitable dust control measures in that processing must be actively pursued in the near future.
Adult↗
Blood pressure, flow, and peripheral resistance of digital arteries in vibration syndrome.
The peripheral circulation was studied in 19 lumberjacks and in 12 control subjects. Twelve of the lumberjacks were free from vascular symptoms and seven had vibration induced white finger (VWF). Using the strain-gauge plethysmographic technique, the digital circulation was examined at rest, during cooling of the upper body, and during heating of the upper body. At rest and during vasodilatation no significant differences were found between the lumberjacks and the controls. During reflexive vasoconstriction, digital blood flow in the upper body was more reduced in lumberjacks with VWF than in control subjects. Furthermore, digital blood pressure of the lumberjacks with VWF fell more than in the control group. The peripheral resistance also increased more, but this difference was not statistically significant. There was no evidence that the exaggerated vasoconstriction of VWF resulted from a narrowing of the lumen of arterioles due to hypertrophy of the vessel wall. The present findings suggest that VWF is produced by the highly sensitive responsiveness of the affected vessel to normal vasoconstrictor stimuli.
Adult↗