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S Nohara

Publications and source records attributed to S Nohara.

34 records · Page 2Linked to original sources
PubMed1992

[Effects of whole-body vibration exposure on DOPAC and VIP-like immunoreactivity in the rat brain].

In order to clarify the involvement of cerebral 3,4-dihydroxyphenylacetic acid (DOPAC) and vasoactive intestinal polypeptide (VIP) in whole-body vibration stress, DOPAC and VIP-like immunoreactivity (VIP-LI) in various discrete brain regions of rats exposed to whole-body vibration (4G, 20 Hz, 90 min) were assayed. The results showed that the whole-body vibration increased the DOPAC level in the frontal cortex and nucleus accumbens, but did not induce a concurrent change of VIP-LI in these regions. VIP-LI was significantly increased in the amygdala, and decreased in the hippocampus, accompanied by no significant change of DOPAC. These results show that whole-body vibration affects cerebral VIP neuron systems in addition to its nonspecific action, i.e. the activation of mesofrontal and mesoaccumbens dopamine neuron systems. It is assumed that the amygdalofugal VIP neuronal system is involved in the regulation of hypothalamic and pituitary hormone secretions, and that VIP in the hippocampus plays a part in modulating the blood circulation in the cortex in whole-body vibration stress.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

[Multivariate analysis on the relationship between subjective symptoms and risk factors for the development of symptoms including working conditions, life habits and physical status in forestry workers using chain saw].

To determine the risk factors of the subjective symptoms experienced by chain saw workers, we surveyed 206 forestry workers using this device in their work. The strength of the relationship between their symptoms and such potential risk factors as occupational, behavioral, and physical factors was evaluated by a multiple logistic regression model. It was found that many years of chain saw operation, and numerous hours of chain saw operation per day, increased the risk of white finger, numbness of hands and arms, chillness of hands and arms and difficulty in joint movement, indicating that these symptoms were closely related to vibration exposure. Many years of forestry work before chain saw work also increased the risk of joint pain, suggesting that bone and joint disorders are related to heavy manual work not using a chain saw. A second job involving manual labor increased the risk of weakness in the arms, stiffness of the shoulders, and lumbago. Infrequent bathing was associated with increased risk of pain in hands and arms and lumbago. Older workers had a higher prevalence of stomach discomfort. No risk factor was found to significantly increase the risk of easy fatigability, forgetfulness and sleep disorder. It was found that not only exposure to vibration but also other factors contributed to the prevalence of pain in hands and arms, joint pain, weakness in arms, stiffness of shoulder, and lumbago. Second job and infrequent bathing appeared to be related to the occurrence of certain subjective symptoms. These contributory factors should be taken into account when evaluating subjective symptoms encountered in field studies of forestry workers.

Behavior↗
PubMed1992

[Experimental studies on the development of acute gastric lesions induced by vibration stress in rats and its pathogenetic mechanisms].

To clarify the pathogenetic mechanisms in acute gastric lesions induced by vibration (VIB), the effects of VIB (3.0 G, 10 Hz, 90 min) on changes in gastric mucosal blood flow (GMBF), plasma corticosterone (COR) and catecholamines (CA) as well as ulcer formation were compared with those of forced water immersion stress (FWI). While the VIB increased the GMBF during the exposure, the FWI decreased it during and after the stress. No difference in the severity of ulcer formation between the VIB groups was seen. Although both VIB and FWI increased the COR and CA, the degree of increased in the COR by the VIB tended to be less than that by the FWI. The truncal vagotomy inhibited the reduction of the GMBF and ulcer formation by the FWI, but promoted the reduction of the GMBF by the VIB. These results suggest that ulceration induced by VIB is caused primarily by its direct, mechanical and specific actions and not through the central nerve system.

Animals↗
PubMed1991

[Multivariate analysis on subjective symptoms in forestry workers using chain saw].

This study was conducted to evaluate the relationship between the prevalence of subjective symptoms in workers using vibrating tools and the duration of chain saw operation and to examine whether the symptoms were relevant to factors other than the usage of vibrating tools. The statistical model of multivariate analysis was adapted to analyze individual data on the subjective symptoms of 317 chain saw operators. The obtained results were as follows: 1. In analysis of covariance, age-adjusted operating year in workers with peripheral circulatory, peripheral neurological and musculoskeletal disturbances was significantly longer than that without such disturbances. For these disturbances, partial regression coefficients of operating year were significantly high in multiple regression analysis. These results show that these disturbances and age-adjusted operating year are mutually closely related. 2. Multiple regression analysis showed that the partial regression coefficients of both operating year and age were low for nine symptoms, i.e. dulling sense of touch, joint pain, headache, dizziness and/or tinnitus, profuse sweating, discomfort of stomach, palpitation and/or dyspnea, hearing disturbance and lumbago. These results suggest that such symptoms were not related to either age or chain saw operation. 3. The results of principal component analysis were visualized in three-dimensional space in order to evaluate the relationships among the symptoms. The analysis showed that peripheral circulatory and neurological disturbances appeared independently and that general symptoms such as easy fatigability, headache, forgetfulness, vertigo and/or tinnitus, easy irritability, sleep disorder, profuse sweating, discomfort of stomach, palpitation and/or dyspnea, shoulder stiffness, hearing disturbance and lumbago consisted of four independent groups. Each group has no relationship with duration of chain saw operation. This suggests other harmful factors of the groups play a role in the prevalence of the symptoms.

Age Factors↗
PubMed1990

Effects of whole-body vibration stress on substance P- and neurotensin-like immunoreactivity in the rat brain.

In order to clarify the involvement of substance P (SP) and neurotensin (NT) neurons in the response of organisms to stress, SP-like immunoreactivity (SP-LI) and NT-like immunoreactivity (NT-LI) were determined in various regions of the rat brain following exposure to the whole-body vibration (20 Hz, 4 G, 90 min). SP-LI and NT-LI in the rat brain were measured by means of a sensitive and specific double-antibody solid-phase enzyme immunoassay. SP-LI in the frontal cortex was significantly reduced following whole-body vibration, while that in the nucleus accumbens and amygdala was significantly increased. NT-LI in both the frontal cortex and the hypothalamus of rats exposed to the whole-body vibration was significantly increased. However, striatal SP-LI and NT-LI remained unchanged. The present findings indicate that the SP and NT neuronal systems in various brain areas are involved in the response to stress. The frontal and amygdalofugal SP and hypothalamic NT neuronal systems, in particular, may have an important role in mediating the response of organisms to the whole-body vibration-induced stress.

Amygdala↗
PubMed1990

[Peripheral circulatory responses to sustained handgrip in workers using vibrating tools].

In order to study the effects of static force such as a handgrip in detail, the peripheral circulatory function and the autonomic nervous function of workers who used chain-saws were examined in a handgrip test at 30% of maximum voluntary contraction (30% MVC). Workers using chain-saws were divided into three groups: group A without any symptoms, group B with numbness and/or pain but without Raynaud's phenomenon and group C with Raynaud's phenomenon. The results obtained were as follows: 1. The finger blood flow (FBF) of all groups significantly decreased during the handgrip and significantly increased after the end of the handgrip as compared with the initial value. There was a tendency for the FBF decrease of group C to be less than that of group A. 2. The mean value of both maximum FBF decrease and maximum FBF increase during handgrip tests fell in alphabetical order (A, B, C). The maximum FBF increase of group C was significantly less than that of group A. 3. The finger skin temperature (FST) of each group significantly fell during the handgrip but there was no significant difference among the three groups. FST returned to the level of the initial value one minute after the end of the handgrip, and significantly rose two minutes and three minutes after the end of the handgrip as compared with the initial value. 4. Both the systolic blood pressure and the diastolic blood pressure of all groups significantly rose during the handgrip but there was no significant difference among the three groups. Concerning the maximum rise of diastolic blood pressure, which is an indicator of autonomic nervous function, there was no significant difference among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Fingers↗
PubMed1990

[Oral findings in severely handicapped patients participating in the periodic dental check-up system for five years--dental caries, gingival recessions and hyperplasias, periodontal diseases].

In March 1987, we investigated the quality of oral hygiene, and the incidence of dental caries and periodontal diseases in 140 severely handicapped patients who had been hospitalized in two national sanatorium. All of the patients had participated under the Matsumoto Dental College Hospital Periodic Dental Check-up System for five years. The results were as follows: 1. The teeth of all the subjects had been brushed by the sanatorium nursing staff twice per day. The prevailing brushing technique was the horizontal method. 2. 37.5% of the subjects showed complete adaptability to the tooth brushing by the nursing staff. However, 2.1% showed no adaptability whatsoever. 3. The mean value of the OHI-S was 1.53. The labial surfaces of the maxillary anterior teeth showed the lowest OHI-S value, while the mandibular left posterior teeth showed the highest. 4. The DMF-T was estimated to be 12.51 (DMFT ratio = 48.2%). The average D-T was 2.07 +/- 4.03, and the average F-T was 8.43 +/- 7.22. 5. 19.3% of the patients were diagnosed with gingival hyperplasia, and 10.7% had local gingival recessions. 1) Of the patients who had taken Phenytoin daily, 35.5% were diagnosed with hyperplasia. 2) Most local gingival recessions were found on the labial gingiva of the mandibular anterior teeth. A relationship was determined to exist the local recession and the horizontal brushing method. 6. 89.2% of the patients suffered from periodontal diseases.(ABSTRACT TRUNCATED AT 250 WORDS)

DMF Index↗
PubMed1987

Tactile perception in hands occupationally exposed to vibration.

The sensory changes that occur in hands occupationally exposed to vibration have been assessed clinically by conventional neurologic tests and, independently, by improved techniques for the determination of tactile spatial resolution (gap detection) and vibrotactile perception thresholds at frequencies from 2 to 400 Hz. Data from 10 forest workers who were exposed to chain saw vibration and seven laboratory workers of similar age, all of whom were screened to exclude confounding factors, revealed, for the first time, three patterns of response, two of which are associated with a vibration-induced neuropathy. The first appears to be characterized by normal or better than normal thresholds in SAI, FAI, and FAII mechanoreceptor types, while a second, extreme response involves elevated thresholds in all three receptor systems (and abnormal two-point discrimination). The third pattern appears to be characterized by elevated thresholds in SAI and/or FAII receptor types.

Hand↗
PubMed1987

Usefulness of blood parameters, especially viscosity, for the diagnosis and elucidation of pathogenic mechanisms of the hand-arm vibration syndrome.

In the present study it was found that, in vibrating-tool operators with Raynaud's phenomenon, whole blood viscosity was significantly higher than in operators without Raynaud's phenomenon at shear rates from 230 to 11.5 s-1. In addition rats were experimentally exposed to local vibration (60 Hz, 5 g) on their hind limbs for 4 h/d for 30 or 90 d. In the case of 30-d exposure, the small arteries in the exposed site did not change. However, after exposure for 90 d, disruption of the internal elastic lamina was observed in the small arteries. The disruption was followed by focal cell proliferation with regenerative formation of collagen and elastic fibers. The fibro-cellular thickening of the intima was further augmented, and, in addition, a complete stenosis of the small lumen of the small artery was observed. Medial thickness did not show significant differences between the control and exposed groups for either exposure duration. The whole blood viscosity was significantly increased by the 90-d but not by the 30-d exposure. These results suggest that there are some relationships between the increase in whole blood viscosity and the intimal thickening of some small arteries in the exposed site.

Animals↗
PubMed1982

An epidemiological study on total and specific IgE levels in Japanese schoolchildren.

Total serum IgE, and specific serum IgE against mites, Ascaris and Japanese cedar pollen were surveyed in 251 schoolchildren by a radioimmunoassay method. These children, aged from 10 to 13 years and living in a rural Japanese town, were selected according to one-third random population sample. A high concentration of total serum IgE (700 u/ml or more) was found in thirty-one children (12 X 3%). The sex ratio of these children, boys to girls, was 2 X 1:1. The cross-sectional and 6-year follow-up study of total IgE levels showed that they decreased with advancing age. Total IgE levels were significantly related to each of three specific IgE species investigated in this study. The levels of these three specific IgE's were also significantly related to each other. Schoolchildren with high specific IgE levels against mites have had significantly more asthmatic histories compared to children with low specific IgE levels. Such a relationship was not observed for total IgE levels and another two specific IgE species.

Adolescent↗