[The importance of the follow-up study on the retired workers--new aspects of the occupational health in our long lived communities].
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Aged↗
Biomedical subjects
R Kishi
Publications and source records attributed to R Kishi.
[Health status, social networks and support systems of elderly men and women in a large city and in former coal-mining areas--a population-based comparative study of 70-year-old residents of Sapporo and Yubari].
In order to analyze the different features of the social network, social support system and health status of elderly people, a survey was performed of the social environment and health related issues among 70 year-old men and women in Sapporo, a large city, and Yubari, a small city which has experienced coal mine closures, both in Hokkaido prefecture. The results were as follows: 1. In Yubari, the health status of the elderly living alone was better than those with other familial categories such as living with their spouse, or with the families of their children. In contrast, the status of the elderly living alone in Sapporo was worse than the others. The mean numbers of out-patient visits and hospital admissions during the previous one year were higher among elderly people living alone in both areas. 2. There were large differences in social support and social network in the two areas and among the living status of the elderly. In particular, persons living alone in Sapporo had statistically significantly lower amount of support than others. Elderly people in Sapporo had fewer contacts with their neighbors and only a small number of them participated in community-based social associations compared with the same age groups in the city of Yubari. 3. An extremely small number of the elderly were provided formal support from official personnel such as public health nurses, district welfare commissioners and so on. The results of this study suggest the need for more formal and informal networks to provide for social support for those elderly men and women living alone in large cities.
Aged↗
Subjective symptoms and neurobehavioral performances of ex-mercury miners at an average of 18 years after the cessation of chronic exposure to mercury vapor. Mercury Workers Study Group.
In order to determine if there are any residual effects of long-term exposure to mercury vapor, neurobehavioral tests were given to ex-mercury miners about 18 years after the cessation of mercury exposure. Seventy-six male ex-mercury miners who had been exposed to relatively high concentrations of mercury vapor (over 1.0 mg/m3) and with a past history of mercury intoxication were compared to age (+/- 3 years)-, sex-, and years of education-matched controls. Although the extent of the workers' symptoms caused by mercury poisoning, termed erethismus merculialis, markedly decreased after the cessation of exposure, the prevalence of neurological symptoms (such as hand tremors, headaches, and slurred speech) and symptoms of senility (such as low-back pain, loss of sexual desire) in the ex-miners was significantly higher than those in the controls. Matched-pair analysis showed that performances of motor coordination, Simple reaction time, and Short-term memory in the ex-miners were significantly deteriorated compared to those of controls. There are slight but persistent effects on neurobehavioral function, especially on motor coordination function, among mercury miners more than 10 years after the cessation of exposure.
Aged↗
Neurobehavioral effects of chronic occupational exposure to organic solvents among Japanese industrial painters.
To investigate the relationship between chronic exposure to organic solvents and changes in central nervous system function, industrial painters were compared with an age- and education-matched referent group of nonexposed workers. Eighty-one male painters completed a symptom questionnaire. Twenty painters underwent both questionnaire and neuropsychological examinations. From the results of pairwise comparisons of the symptoms, dry and scaly skin, being easily depressed without reason, coldness of hands and legs, being easily irritated without reason, loss of appetite, dizziness, and unsteadiness occurred statistically significantly more often among the exposed subjects than among the referents. Performances on the Digit symbol test and vocabulary test scores (synonyms) in exposed subjects were significantly lower than those of controls. In multiple regression models, controlling for age, education, and alcohol intake, a significant relation was found between the duration of the solvent exposure and poor performance in both the Block design and Digit span tests. The relation between toluene exposure and poor performance in both the Santa Ana coordination test and the Benton visual retention test was also significant. The results suggest that a symptom inquiry and some behavioral tests are helpful for detecting the possible effects of exposure to low levels of organic solvents. However, no consistent pattern was observed in regard to the effects of organic solvent exposure on neurobehavioral function, which is coincident with the type I toxic central nervous system disorder as classified by the World Health Organization.
Adult↗
Acute neurobehavioral effects of co-inhalation of toluene and n-hexane on schedule-controlled behavior in rats.
Whether coexposure to toluene and n-hexane had any combined effects on the shock avoidance performance in rats was studied. Eighteen Wistar male rats with an avoidance rate of over 80% were selected and divided to three groups based on performance and body weight: (1) toluene, (2) n-hexane, and (3) toluene + n-hexane. Each group was exposed alternately first to air and then to a particular organic solvent for 4 hr at various concentrations (50, 100, 200, 400, or 800 ppm, in ascending order). The effects of each organic solvent were evaluated by comparing the performance of rats during and after exposure with their own performance under the sham exposure to air by three-way ANOVA. The main results were that (1) 200, 400, or 800 ppm toluene exposures increased lever press rates, (2) 50 ppm n-hexane exposure decreased lever press and avoidance rates in a transitory manner and 800 ppm n-hexane exposure increased the lever press rate, (3) the 50 ppm mixture (25 ppm toluene + 25 ppm n-hexane) decreased lever press and avoidance rates persistently during and after the 4-hr exposure and the 800 ppm mixture (400 ppm toluene + 400 ppm n-hexane) decreased lever press and avoidance rates unpredictably when compared to the results of 400 or 800 ppm of toluene or n-hexane alone. In conclusion, n-hexane showed narcotic effects at 800 ppm and modified the acute neurobehavioral effects of toluene in rats at 400 ppm toward unpredictable results.
Administration, Inhalation↗
Distribution of radioactivity from 14C-formaldehyde in pregnant mice and their fetuses.
The distribution of 14C after the administration of 14C-formaldehyde was studied in pregnant mice by a whole body low temperature autoradiographic technique. The concentrations of formaldehyde and its metabolites in maternal and fetal blood and tissues were determined in unsectioned tissues by liquid scintillation spectrophotometry. The binding of 14C from 14C-formaldehyde to cells and DNA in maternal and fetal mouse liver was also measured. Radioactivity of 14C deriving from 14C-formaldehyde was found immediately after injection, and showed strong accumulation and retention three hours after injection. The organs that had high concentrations at all studied survival intervals were maternal liver, intestinal mucosa, bone marrow, kidneys, and salivary glands. Considerable amounts of radioactivity were found in the fetuses at six hours after injection, and the concentrations were almost the same as in the maternal tissues. The elimination of 14C-formaldehyde and metabolites from the placenta and fetus occurred more slowly than from maternal tissue.
Animals↗
Circadian variations of acute toxicity and blood and brain concentrations of inhaled toluene in rats.
To investigate circadian variations in the acute toxicity of toluene, rats were exposed to it (2000 ppm or 4000 ppm) both in the dark (the animals' active phase) and the light (the inactive phase) for 4 hours. The performance decrements of rats were greater in the light phase than in the dark phase in all time zones of exposure to toluene. In the dark phase, the performance recovered almost to that pre-exposure, whereas a significant delay of recovery was noted in the light phase. The differences in the number of lever presses between exposure to 2000 ppm toluene and control (air) exposure were also greater in the light phase than in the dark phase. Significant differences according to the time of exposure were also found in toluene concentrations in blood and the brain. Both blood and brain concentrations in the light phase were higher than those in the dark phase at four hours after exposure to 2000 ppm toluene or at two hours after exposure to 4000 ppm toluene. These results suggest that there was a significant difference in circadian susceptibility after exposure to toluene, which might be caused by circadian differences in the pharmacokinetics of toluene in the light and dark phases.
Animals↗
Acute effects of trichloroethylene on blood concentrations and performance decrements in rats and their relevance to humans.
This study was designed to clarify the nature of effects of trichloroethylene (TCE) on the central nervous system, and to determine the critical concentrations in blood associated with specific behavioural changes. This was achieved by a follow up of the whole time course of TCE intoxication during and after exposure. The effects of a single four hour exposure to TCE on signalled bar press shock avoidance in rats were tested by methods previously applied to investigate the acute neurobehavioural effects of exposure to toluene. Even low exposure to TCE induced shock avoidance performance decrements in rats. Rats exposed to 250 ppm TCE showed a significant decrease both in the total number of lever presses and in avoidance responses at 140 minutes of exposure compared with controls. The rats did not recover their pre-exposure performance until 140 minutes after the exhaustion of TCE vapour. Exposures in the range 250 ppm to 2000 ppm TCE for four hours produced concentration related decreases in the avoidance response rate. No apparent acceleration of the reaction time was seen during exposure to 1000 or 2000 ppm TCE. The latency to a light signal was somewhat prolonged during the exposure to 2000 to 4000 ppm TCE. It is estimated that there was depression of the central nervous system with slight performance decrements and the corresponding blood concentration was 40 micrograms/ml during exposure. Depression of the central nervous system with anaesthetic performance decrements was produced by a blood TCE concentration of about 100 micrograms/ml. These results showed effects of TCE on the central nervous system that were considered to be a function of both the exposure concentration and the duration of exposure, which are closely related to the TCE concentration in blood.
Animals↗
[Association of parents' occupational exposure to cancer in children. A case-control study of acute lymphoblastic leukemia].
The objectives of the present study were to evaluate the preconceptual, prenatal, and postnatal environmental factors as possible etiologic agents of childhood neoplasms. An exploratory case-control study was conducted on parents of children less than 15 yr of age with acute lymphocytic leukemia (ALL). Data were obtained on 147 identified cases by interview from their mothers and by mail questionnaire from their fathers. Hospital control cases were matched by sex and age, while population control cases were matched by place of residence, and sex. The following results were obtained. 1) As for the occupation of the parents, more fathers of the cases were engaged in occupations related to agriculture, medicine, and science than those of the controls, and more mothers of the cases were engaged in agriculture than those of the controls. 2) No significant relation could be demonstrated between ALL and occupations related to hydrocarbon and ionizing radiation. 3) The results of multivariate analysis showed that in comparison with the hospital control cases the preconceptual exposure to chemicals and the prenatal exposure to pesticides of the fathers and the prenatal exposure to benzine and spray pesticides of the mothers were risks of high significance. In comparison with population control cases, the prenatal exposure of benzine and exposure to paints of the mothers prior to disease onset were risks of high significance. The foregoing results suggest that exposure to occupational and environmental factors of the parents may play an etiologic role in childhood leukemia.
Adolescent↗
[Studies on fatigue and stress of anesthesiologist during anesthetic works using Holter ECG].
We evaluated fatigue, stress and workload of anesthesiologists during anesthetic works using Holter ECG. Recorded heart rates of anesthesiologists enable us to draw the task graph and to calculate the workload scores according to their task behavior. We conclude that the application of Holter ECG is useful in measuring the fatigue, stress, and especially workload of anesthesiologists.
Anesthesiology↗
[Fatigue and stress of anesthesiologists at work].
We studied the fatigue and stress of anesthesiologists at work using a flicker photometer, visual reaction time test and questionnaires to them. The two kinds of visual apparatus enabled us to measure two types of fatigue. On the other hand, the questionnaires relating to fatigue and stress indicated the stress tendencies and stressors by age, anesthetic experience, and sex. The results suggest that these methods are useful for measuring the fatigue and stress of anesthesiologists.
Adult↗
Neurochemical effects in rats following gestational exposure to styrene.
Styrene was evaluated for the reproductive effects of pregnant rats and the neurochemical effects in the offspring of rats exposed during gestation. Pregnant Wistar rats were exposed to 0, 50, or 300 ppm styrene for 6 h/day during days 7 to 21 of gestation. No significant differences in the number of offspring delivered were observed between the exposed and control groups. Body weights at 1 day of age of the offspring whose mothers were exposed to styrene were significantly lower than those of the control group. Although, there were neither statistically significant differences of protein contents nor brain weights among styrene-exposed and their control offsprings of rats, analyses of neurotransmitter studies showed dose-dependent decreases of neuroamines, especially 5-HT (serotonin) and its metabolite 5HIAA (5-hydroxyindoleacetic acid) in the newborn offspring of styrene-exposed rats. The results suggest that gestational exposure to styrene at these concentrations does not produce apparent reproductive toxicity but affects the body weight of pups and causes lowering of the neurotransmitter levels in the brain.
Administration, Inhalation↗
Central cholinergic action produces antagonism to ketamine anesthesia.
Ketamine sometimes produces posthypnotic emergency reactions, such as prolonged hallucination or delirium. In a previous paper, we showed that physostigmine, an anticholinesterase agent, counteracts the manifestation of effects of ketamine at some doses. In the present study, we investigated the mechanism of the antagonistic effect of physostigmine on ketamine anesthesia. At first, rats were given ketamine 75 mg/kg. Immediately after the loss of righting reflex, the four groups of rats were given one of the three central cholinergic agents, physostigmine 0.1 mg/kg, oxotremorine 0.05 mg/kg, 4-aminopyridine 3 mg/kg, or saline as the control. The sleeping times were 10.7 +/- 1.0, 12.3 +/- 0.9, 11.4 +/- 1.3 and 21.2 +/- 0.7 min, respectively. The three cholinergic agents antagonized ketamine anesthesia. In the other groups of rats, the central anticholinergic agent, l-hyoscyamine, 0.5 mg/kg, was given subcutaneously for premedication before the above-mentioned procedure. The sleeping times were 16.3 +/- 1.2 min in the physostigmine group, 18.7 +/- 1.0 min in the oxotremorine group and 18.6 +/- 0.8 min in the 4-aminopyridine group. The sleeping time was significantly longer in the premedicated group than in the non-premedicated group, in the case of the three central cholinergic agents. The sleeping time in the saline group, 20.0 +/- 0.4 min, was not significantly different from that of the control in the non-premedicated case. It is, therefore, considered that the central cholinergic action produces antagonism to ketamine anesthesia.
4-Aminopyridine↗
Sex-, age- and pregnancy-induced changes in the metabolism of toluene and trichloroethylene in rat liver in relation to the regulation of cytochrome P450IIE1 and P450IIC11 content.
Sex-, age- and pregnancy-induced changes in the metabolism of toluene and trichloroethylene in rat liver were investigated in relation to the regulation of cytochrome P450IIE1 and P450IIC11 content using monoclonal antibodies. Immature male rats had a higher level of microsomal protein than females, and this increased with development; however, no difference by sex was found at puberty. No difference in cytochrome P450 content was seen between immature male and female rats; the content increased with development only in males, so that a sex difference in cytochrome P450 content occurred at puberty. Pregnancy decreased the cytochrome P450 content but not that of the microsomal protein. The rate of formation of benzyl alcohol from toluene was 4 times higher in mature than in immature male rats at a high concentration of toluene, but no difference was seen at a low toluene concentration. In contrast, the rate was lower in mature female rats than in immature ones at a low toluene level and no difference was seen at the high concentration. A sex difference was thus found in benzyl alcohol formation at puberty at both concentrations of toluene. The levels of o- and p-cresol formation in liver were similar in males and females but the rate decreased during development of females. The rate of metabolism of trichloroethylene was higher in immature than in mature male and female rats, especially at a low substrate level, and no sex difference in metabolism was seen with either age or concentration of trichloroethylene. Pregnancy decreased the metabolism of both toluene and trichloroethylene.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
Occurrence of L-2,4-diaminobutyrate decarboxylase activity in Acinetobacter.
Three strains of the genus Acinetobacter grown in a polyamine-free synthetic medium contained very high amounts of 1,3-diaminopropane, and there were also high concentrations in the extracellular growth medium. Little, if any, of the usual polyamines, putrescine, spermidine and spermine were found. There was no detectable activity of aminopropyltransferase (greater than 0.2 nmol spermidine formed/mg protein/h), which would be responsible for the formation of spermidine or spermine, expected precursors of 1,3-diaminopropane. These observations suggested the possibility of another mode of 1,3-diaminopropane biogenesis. Decarboxylation activity towards L-2,4-diaminobutyrate leading to the formation of 1,3-diaminopropane was detected in extracts of all three strains examined. The decarboxylase was partially purified from A. calcoaceticus ATCC 23055. The enzyme was active against only L-2,4-diaminobutyrate among the diamino acids tested and required pyridoxal phosphate as a cofactor. Mg2+ activated the enzyme.
Acinetobacter↗
Symptoms among workers with long-term exposure to methyl bromide. An epidemiological study.
Symptoms as an important sign of the effects of methyl bromide were studied in 56 male workers (37 currently exposed and 19 previously exposed) in a methyl bromide factory. The workers were 18 to 62 yr of age (mean age: 41) and were exposed from 1 to 25 yr (mean: 7 yr). They were compared to 56 age-matched referents with a standardized questionnaire. The results of pairwise comparison of the symptoms of the age-matched pairs of exposed and referent subjects showed that the occurrence of dizziness, numbness, paresthesia and weakness of extremities, nightmares, fatigue and dry and scaly skin was statistically significantly higher among the workers than among the referents. When the symptoms during the work shift (acute symptoms) were compared, irritation symptoms such as itching, bullae or reddish swollen hands and runny noses with nasal irritation were reported significantly more often in the exposed groups. The correlation of the symptoms among the exposed workers suggested that chronic symptoms are closely related to acute irritation symptoms and exposure duration. The results suggest that symptom inquiry is useful for detecting the possible effects of exposure to methyl bromide.
Adult↗
[Distribution of 14C-formaldehyde in pregnant mice: a study by liquid scintillation counter and binding to DNA].
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Animals↗
Antagonistic effect of physostigmine on ketamine-induced anesthesia.
Effects of physostigmine on ketamine-induced anesthesia and analgesia were studied in male Sprague-Dawley rats using behavioral tests. Rats were divided into six groups. Immediately after loss of the righting reflex following an intraperitoneal injection of ketamine 75 mg/kg, each group of rats was given an intraperitoneal injection of either physostigmine 0.05, 0.1, 0.2, 0.4, 0.6 mg/kg or saline as the control, respectively. Physostigmine 0.1 mg/kg caused the greatest antagonistic effect on ketamine anesthesia as indicated by sleeping time, duration of ataxia and motor coordination. The antagonistic effects of physostigmine were reduced by a dose of physostigmine of greater than 0.1 mg/kg. However, at no dose did physostigmine antagonize ketamine analgesia as indicated by the tail-flick latency. Physostigmine (0.4 and 0.6 mg/kg) itself had analgesic and motor-suppressive actions. It can therefore be presumed that there is a limited threshold of the dose of physostigmine which develops an antagonistic effect on ketamine anesthesia due to the motor-suppressive action. It is also confirmed that physostigmine itself produces analgesia, and does not antagonize ketamine-induced analgesia.
Anesthesia↗