Masaiwa Inoue

Prevalence of Cervical Spondylosis and Musculoskeletal Symptoms among Coolies in a City of Bangladesh

Prevalence of Cervical Spondylosis and Musculoskeletal Symptoms among Coolies in a City of Bangladesh: Md H. Mahbub, et al. Department of Hygiene, Yamaguchi University School of Medicine—To assess the prevalence of cervical spondylosis and musculoskeletal symptoms among coolies a cross‐sectional study was performed in Narayangonj City of Bangladesh on a random sample of 98 male coolies, using a questionnaire and the results of cervical spine X‐rays. Statistical associations were investigated using the chi‐square test. The results show a considerably higher prevalence of cervical spondylosis among the coolies (39.8%). More than half (51.3%) of the cases of cervical spondylosis were in subjects below the age of 40 yr, and a significant association was found between age group and prevalence of cervical spondylosis. The study also observed a significant association between duration of occupation and prevalence of cervical spondylosis. Coolies who had worked for 10 to 15 yr, or more than 15 yr, had higher rates of cervical spondylosis. In this study it was found that those who carried heavier loads suffered more from cervical spondylosis. Musculoskeletal symptoms in multiple body regions (two or more) were more prevalent (61.2%) than those in single body region (29.6%). Symptoms in the hands/ fingers were the most frequent followed by the back and arms/forearms. In conclusion, the high prevalence of cervical spondylosis and musculoskeletal symptoms among professional coolies may be associated with the practice of carrying heavy loads on the head. Further study with a large sample of population is required to investigate this problem and to explore preventive measures.

Evaluation of the Effect of Heat Exposure on the Autonomic Nervous System by Heart Rate Variability and Urinary Catecholamines

Evaluation of the Effect of Heat Exposure on the Autonomic Nervous System by Heart Rate Variability and Urinary Catecholamines: Shinji Yamamoto, et al. Department of Hygiene, Yamaguchi University Graduate School of Medicine—The aim of this study was to investigate the usefulness of heart rate variability (HRV) and urinary catecholamines (CA) as objective indices of heat stress effect. We examined physiological responses, subjective symptoms, HRV and urinary CA to evaluate the effect of heat exposure on the autonomic nervous system. Six healthy male students volunteered for this study. They were exposed on different days to either a thermoneutral condition at wet bulb globe temperature (WBGT) 21°C, or a heated condition at WBGT 35°C for 30 min, while seated on a chair. In the thermoneutral condition, differences of all parameters between the values before and after 30 min exposure were not statistically significant. In the heated condition, heart rate, body temperature and scores for subjective symptoms (feverishness, sweating, mood, and face flushing) significantly increased after 30 min exposure (p<0.05). Also, the high frequency component (HF%) of HRV significantly decreased and the low frequency/high frequency (LF/ HF) ratio of HRV significantly increased after 30 min exposure to the heated condition (p<0.05). There were no significant differences between the amounts of urinary CA before and after the 30 min exposures; however, the norepinephrine amount after 30 min exposure to the heated condition was significantly greater than that of the thermoneutral condition (p<0.05). The heat exposure (WBGT 35°C) induced activation of the sympathetic nervous system and a withdrawal of the parasympathetic nervous system. These findings coincide with observed changes of heart rate, body temperature and subjective symptoms. It is suggested that HRV (HF% and LF/HF ratio) and urinary norepinephrine may be useful objective indices of heat stress; HRV seems to be more sensitive to heat stress than urinary CA.

Influence of Differences in Their Jobs on Cardiovascular Risk Factors in Male Blue-collar Shift Workers in Their Fifties

Abstract This study examined relationships between different job types of shift work and hypertension, obesity, and dyslipidemia. Male blue-collar workers 50-59 years of age (n = 210) bn the same three-shift schedule in a pulp and paper mill were divided into two groups; 118 in paper manufacturing (group 1) and 92 in the chemical products section (group 2). Only the frequency of hypertension differed significantly (p = 0.012) between the groups, 52.2% (n = 48) in group 2 vs 33.9% (n = 40) in group 1. The odds ratio for group 2 in relation to hypertension was 2.3 (95% CI 1.2–4.2). These results indicate a positive association between job type of shift work and hypertension and suggest that different job types of shift workers should not be combined when the effects of shift work on blood pressure are being examined.

Factors associated with contraceptive practices of married women in Bangladesh with respect to their employment status

Objective There might be a difference between non-working and working women in their perception of rights and privileges which may influence their contraceptive behavior. The purpose of this study was to examine contraceptive behavior among non-working and working women in Bangladesh determining associated factors. Method Analysis was based on data from the 1999–2000 Bangladesh Demographic and Health Survey which employs nationally representative sample. Results The prevalence of current contraceptive use (any method) was 58.2% among non-working women and 65.5% among working women. Both rates are still low for the country. Some factors, such as discussed family planning with husband, husband approves family planning, desire for more children, and husband lives together, were influential determinants of lower contraceptive prevalence among the non-working women. Conclusion The results indicate a necessity for social activities promoting husband–wife communication and womens participation in employment to enhance the use of contraceptives among Bangladeshi women, especially non-working women.

Caudal ventrolateral medullary depressor area controls cerebral circulation via rostral ventrolateral medullary pressor area.

The cerebral blood flow (CBF) was determined by radiolabeled microsphere technique in urethane (1.1–1.5 g·kg−1, i.p.) anesthetized Wistar rats. Microinjection of L-glutamate (1.7 nmol) into the ventrolateral medullary depressor area (VLDA) produced a significant (P<0.01) decrease in CBF from 64±9 (mean ± S.E.M.) to 48±9 ml·min−1·(100g)−1 and a significant (P<0.01) increase in cerebrovascular resistance (CVR) from 1.7±0.2 to 2.4±0.4 mmHg per [ml·min−1(100g)−1] in the cerebral cortex ipsilateral to the stimulated VLDA side but not in other structures such as brain stem and cerebellum (n=9). Cervical sympathectomy blocked the decrease in CBF and increase in CVR elicited by chemical stimulation of the VLDA (n=10). Depression of the ventrolateral medullary pressor area (VLPA) neurons induced by microinjection of muscimol into the VLPA blocked the CBF decrease and CVR increase following chemical stimulation of the VLDA (n=11). Microinjection of the vehicle solution into the VLDA had no effects on systemic and cerebral circulation (n=7). These results suggest that a vasoconstrictor pathway to control cerebral vessels involves an excitatory projection from the VLDA to the VLPA and the changes in cerebral circulation are mediated by the cervical sympathetic nerves.

Assessing the Influence of Antivibration Glove on Digital Vascular Responses to Acute Hand-arm Vibration

Assessing the Influence of Antivibration Glove on Digital Vascular Responses to Acute Hand‐arm Vibration: Md H. Mahbub, et al. Department of Hygiene, Yamaguchi University School of Medicine—This study was designed to assess the influence of an antivibration glove on digital vascular responses in healthy subjects exposed to short‐term grasping of a vibrating handle. To measure finger blood flow (FBF) and finger skin temperature (FST) once at the end of every min, a blood flowmeter sensor was attached to the dorsum and a thermistor sensor was attached to the medial surface of the subjects middle phalanx of the third finger of the right hand. After 5 min of baseline measurements without or with an antivibration glove meeting ISO standard 10819, worn on the right hand, subjects gripped a vibrating handle with the same hand for a period of 5 min. Vibration was generated at two frequencies of 31.5 Hz and 250 Hz with a frequency weighted rms acceleration of 5.5 m/s2. FBF and FST continued to be recorded for a further 5 min after release of the vibrating handle. Statistical analysis showed no significant change after vibration exposure in either FST or FBF at 250 Hz, compared to baseline (control) measurements while using the antivibration glove. At 31.5 Hz, FBF data exhibited a significant difference between before and after grasping of vibrating handle, which was less under the condition of wearing the antivibration glove than under the condition of bare hand. The results provide evidence that the antivibration glove considerably influenced finger vascular changes in healthy subjects induced by vibration exposure, especially against high frequency vibration. Further studies are required to assess finger vascular responses to hand‐transmitted vibration with antivibration gloves of different manufacturers.

Regional differentiation of blood flow responses to microinjection of sodium nitroprusside into the nucleus tractus solitarius of anesthetized rats

This study was undertaken to examine the effects of the activation of the neurons in the nucleus tractus solitarius (NTS) via microinjection of sodium nitroprusside (SNP), which spontaneously releases nitric oxide (NO), on the blood flows of the spleen, kidney, liver, brain and spinal cord and to investigate the regional differentiation of the blood flow changes between those organs. Employing urethane-anesthetized (1.5 g kg-1, i.p.), paralyzed and artificially ventilated rats, regional blood flows of those organs were determined simultaneously using radiolabeled microspheres (109Cd, 51Cr and 85Sr) Unilateral microinjection of SNP into the NTS (n = 9) decreased brain blood flow from 71 +/- 8 (mean +/- S.E.) to 54 +/- 6 (P < 0.01) and spinal cord blood flow from 58 +/- 8 to 43 +/- 5 ml min-1 (100 g)-1 (P < 0.05) and increased brain vascular resistance from 1.18 +/- 0.13 to 1.48 +/- 0.15 (P < 0.01) and spinal cord vascular resistance from 1.46 +/- 0.17 to 1.80 +/- 0.16 (P < 0.05) mmHg per [ml min-1 (100 g)-1]. Whereas the microinjection of SNP into the NTS increased splenic blood flow from 127 +/- 25 to 188 +/- 27 (P < 0.01) and renal blood flow from 346 +/- 28 to 371 +/- 26 ml min-1 (100 g) (P < 0.05) and decreased splenic vascular resistance from 0.77 +/- 0.13 to 0.44 +/- 0.06 (P < 0.01) and renal vascular resistance from 0.24 +/- 0.02 to 0.21 +/- 0.01 mmHg per [ml min-1 (100 g)-1] (P < 0.05). The blood flow of the liver was not significantly altered. Unilateral microinjection of NG-monomethyl-L-arginine, an inhibitor of the formation of NO from L-arginine, into the NTS (n = 10) did not significantly change the blood flows of all organs examined except for an increase in blood flow of the kidney. Unilateral microinjections of SNP into the area adjacent to the NTS (n = 9), of artificial cerebrospinal fluid into the NTS (n = 7) and of light-inactivated SNP into the NTS (n = 6) did not significantly alter the blood flows of all organs examined. These results suggest than the neurons in the NTS have a vasoconstrictor effect on the brain and spinal cord circulation and a vasodilator effect on the splenic and renal circulation. There is a regional qualitative differentiation of the blood flow responses between these organs during activation of the neurons in the NTS.

Habitual Smoking and Musculoskeletal Symptoms in Japanese Blue-Collar Workers

Habitual Smoking and Musculoskeletal Symptoms in Japanese Blue‐Collar Workers: Masaiwa Inoue, et al. Department of Hygiene, Yamaguchi University School of Medicine— Whether smoking is associated with musculoskeletal disorders is still debatable. To determine the prevalence of musculoskeletal disorders among smoking and non‐smoking employees doing strenuous physical work, we conducted a survey by means of a questionnaire that was distributed as a part of the annual health examination in a pulp and paper mill. The questions included smoking habit and musculoskeletal symptoms in the neck, arms, shoulders, back and low back. The analysis was performed on 905 male employees working in the manufacturing plant. For most age groups and regions, the percentage of smokers was greater among subjects with symptoms than among subjects without symptoms. Particularly among subjects in their 20s and 50s, there were significant differences in the percentage of smokers with symptoms and the percentage of smokers without symptoms (P<0.01 for both age groups). Although the percentage of ex‐smokers was greater among subjects without symptoms than among subjects with symptoms, the difference was not significant except among subjects in their 50s (P=0.023). The percentages of ex‐smokers in their 50s were greatest among subjects without symptoms for all 5 musculoskeletal regions. When the percentages of current smokers were analyzed according to the number of regions in which musculoskeletal symptoms were present, the number of regions tended to increase with the percentage of smokers but not significantly. Our study supports an association between habitual smoking and musculoskeletal symptoms with a proposal for an educational campaign aimed at helping individuals quit smoking.

CEREBRAL BLOOD FLOW DECREASES FOLLOWING MICROINJECTION OF SODIUM NITROPRUSSIDE INTO THE NUCLEUS TRACTUS SOLITARII OF ANESTHETIZED RATS

The present study was undertaken to examine the effects of microinjection of sodium nitroprusside (SNP), which releases nitric oxide (NO) spontaneously, into the nucleus tractus solitarii (NTS) on cerebral circulation. Cerebral blood flow (CBF) was measured in urethane-anesthetized (1.5 g·kg−1, i.p.), paralysed and artificially ventilated rats using labeled microspheres or laser Doppler flowmetry. The CBF was significantly decreased by microinjection of SNP (5 nmol, n=10, microsphere technique; 0.5 nmol, n=6, laser Doppler flowmetry) into the unilateral NTS. Microinjection of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of the formation of NO, prevented cerebral vasoconstrictor responses induced by microinjection of l-glutamate into the NTS (n=10). Microinjection of NG-monomethyl-d-arginine (D-NMMA) had no effect on the cerebral vasoconstrictor responses induced by l-glutamate (n=11). Unilateral microinjections of L-NMMA into the NTS (n=9), of SNP into the area adjacent to the NTS (n=9), of vehicle solution into the NTS (n=10), and of light-inactivated SNP into the NTS (n=6) had no effect on cerebral circulation. Cerebral autoregulation was well maintained in our protocols (n=9). These results indicate that microinjection of SNP, an NO donor, into the NTS decreases CBF.

Spinal cord blood flow decreases following microinjection of sodium nitroprusside into the nucleus tractus solitarii of anesthetized rats

This study was undertaken to examine whether or not nitric oxide (NO) is involved in synaptic transmission in the nucleus tractus solitarius (NTS) during control of the spinal cord circulation. Employing urethane-anesthetized, paralyzed and artificially ventilated rats, sodium nitroprusside (SNP), which produces NO, was microinjected unilaterally into the NTS and the spinal cord blood flow (SCBF) was determined using labeled microspheres. Arterial blood pressure (ABP) was decreased by unilateral microinjection of SNP into the NTS, but its value was kept within the normotensive range by blood transfusion, in order to measure SCBF at normotension. After microinjection of SNP into the NTS, the SCBFs of the cervical, thoracic and lumbar cords decreased significantly from 63 +/- 8 (mean +/- S.E.M.) to 49 +/- 7 (P < 0.05), from 54 +/- 7 to 37 +/- 7 (P < 0.05), and from 77 +/- 9 to 58 +/- 8 (P < 0.05) ml/min/(100 g), respectively (n = 10). Prior microinjection of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of the formation of NO from L-arginine, into the NTS blocked the spinal cord vasoconstrictor response produced by microinjection of L-glutamate into the NTS (n = 10). Prior microinjection of NG-monomethyl-D-arginine (D-NMMA), which does not inhibit the formation of NO from L-arginine, did not block the spinal cord vasoconstrictor response elicited by microinjection of L-glutamate (n = 11). Unilateral microinjection of L-NMMA into the NTS exerted no effect on the spinal cord circulation (n = 9). These findings suggest that NO may be involved in the control of the spinal cord circulation in the NTS.