Immunomodulatory action of chronic exercise on macrophage and lymphocyte cytokine production in mice

This study was designed to evaluate the effects of 8-week voluntary running exercise on cytokine production of macrophages and lymphocytes. Seven-week-old-male BALB/c inbred mice were divided into two groups: a group given voluntary exercise (exercise group, n=32), and the other, a non-exercise group (control group, n=32). Exercise consisted of spontaneous running in wheels for 3 days per week over 8 weeks. The levels of nitric oxide (NO2-) and interleukin (IL)-1 beta production by lipopolysaccharide (LPS)-stimulated peritoneal macrophages from the exercise group was significantly higher than that in the control group (P < 0.05-P < 0.01). In the exercise group, stimulation indices by concanavalin A (Con A) was significantly higher than they were in the control group (P < 0.05-P < 0.001). When compared with the control group, the exercise group showed a significant (P < 0.05) increase in the splenic lymphocyte production of IL-2 stimulated by Con A (449.5 +/- 28.2 and 853.7 +/- 116.0 pg 4 x 10(5) cells(-1) 48 h(-1) for the control group and the exercise group, respectively). IL-4 production of splenocytes stimulated by Con A in the exercise group (37.6 +/- 5.1 pg 4 x 10(5) cells(-1) 48 h(-1)) was higher than that in the control group (30.9 +/- 3.9 pg 4 x 10(5) cells(-1) 48 h(-1)); however, the difference was not statistically significant. These results suggest that 8-week voluntary running exercise effectively enhanced macrophage and lymphocyte functions in mice.

Immunohistochemical study of vestibular gingival blood vessel density and internal circumference in smokers and non-smokers

BACKGROUND

This study was undertaken to determine: 1) if sections stained with monoclonal antibody to CD34 can be used for measurement of gingival blood vessel density and circumference and 2) if long-term smoking affects either of these 2 parameters.

METHODS

Vestibular gingival biopsy samples were obtained from 17 adults (5 smokers and 12 non-smokers) who were undergoing routine periodontal surgery independently of this study. Hematoxylin and eosin staining was used for histological assessment of inflammation, while immunohistochemical staining with CD34 mouse monoclonal antibody was used to mark the endothelial cells of the blood vessels within each sample. Stringent selection criteria were applied to the 17 biopsy samples, and 7 (from 3 smokers and 4 non-smokers) were chosen to have their vascular density (number of vessels/unit area) and internal vessel circumference (IC) measured under a blinded protocol.

RESULTS

Repeated measurements of vascular density and internal circumference showed small standard deviations, indicating the high reproducibility of the measurement technique. The smoker group showed a higher proportion of small (IC < 50 microns) and a lower proportion of large blood vessels (IC > 100 microns), which was statistically significant (P = 0.0403 and P < 0.001, respectively). The difference between the vascular density of smokers and non-smokers was not significant (P = 0.092).

CONCLUSIONS

The present study indicates that the CD34 immunohistochemical staining technique is a simple and reproducible method for the measurement of density and internal circumference of gingival blood vessels. Based on this technique, cigarette smokers show a higher percentage of smaller blood vessels and a lower percentage of larger vessels, but similar vascular density, to non-smokers.

Effects of different durations of exercise on macrophage functions in mice

The effects of differing durations of daily exercise on macrophage functions in mice were studied. Male ICR mice aged 4 wk were divided into five groups: a nonexercise group (control) and four exercise groups with differing daily exercise durations of 15--120 min (Exr groups). The exercise applied was 5 days/wk treadmill running at 13 m/min for 12 wk. The potentiation of the phagocytosis function of the reticuloendothelial system and the glucose consumption of peritoneal macrophages in the Exr 30, 60, and 120 groups were significantly higher than those in the control group. Superoxide anion production of peritoneal macrophages in both the absence and the presence of phorbol 12-myristate 13-acetate in the Exr 60 and 120 groups was significantly higher than that in the control group. The acid phosphatase and beta-glucuronidase activities of peritoneal macrophages in the Exr 30, 60, and 120 groups were significantly increased. These results suggest that treadmill running exercise for at least 30 min/day (30--120 min) effectively enhances macrophage functions in mice. These data provide preliminary evidence indicating that chronic exercise-induced increases in phagocytic activity exhibit a dose-dependent relationship with exercise duration.

Enhanced macrophage functions and cytokine production of lymphocytes after ingestion of bon narine in female BALB/c mice

The purpose of this investigation was to determine the effects of bon narine treatment on macrophage and lymphocyte functions in mice. Twelve week-old female inbred BALB/c mice were given bon narine p.o. at 30 mg/kg per day and sacrificed after three months. Glucose consumption of peritoneal macrophages in the bon narine treated group during incubation up to 72 h was significantly higher than that in the control group. Activities of acid phosphatase (APH), beta-glucuronidase (GLU) and lactate dehydrogenase (LDH) in the peritoneal macrophages in the bon narine treated group significantly increased compared to that in the control group. Macrophage production of nitric oxide stimulated by lipopolysaccharide (LPS) in the bon narine treated group was significantly increased. Interleukin-1beta (IL-1beta) production of peritoneal macrophages stimulated by LPS was significantly higher in the bon narine treated group. Stimulation indices in splenic lymphocytes by concanavalin A (Con A) in the bon narine treated group were significantly higher than that in the control group. Interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) production stimulated by Con A were significantly increased in the bon narine treated mice. Interleukin-4 (IL-4) production of splenic lymphocytes stimulated by Con A was not different in the control group and the bon narine treated group. These findings might suggest that oral administration of bon narine effectively enhanced the macrophage function and lymphocyte responsiveness in mice.

Tobacco-associated lesions of the oral cavity: Part II. Malignant lesions

Nonmalignant tobacco-associated lesions of the oral cavity were discussed in the first part of this two-part article. Here, we describe malignant lesions associated with tobacco use, basic biopsy principles for such lesions and intervention strategies that dental professionals may use to reduce the chances of their patients developing precancerous lesions or primary malignancies.

Tobacco-associated lesions of the oral cavity: Part I. Nonmalignant lesions

The excessive use of tobacco products has been associated with various lesions in the oral cavity. Tobacco-associated lesions include tooth stains, abrasions, smoker's melanosis, acute necrotizing ulcerative gingivitis and other periodontal conditions, burns and keratotic patches, black hairy tongue, nicotinic stomatitis, palatal erosions, leukoplakia, epithelial dysplasia and squamous-cell carcinoma. A routine intraoral examination by a dental health professional can reveal most of these lesions at an early stage, and early intervention may prevent serious sequelae. Thus, detection of tobacco-associated lesions in conjunction with tobacco-use counselling by dental professionals has become the standard of care. The significance and treatment of nonmalignant tobacco-associated lesions are addressed in the first part of this two-part series. Malignant lesions, basic biopsy principles and prevention and intervention strategies are discussed in the subsequent part.

Immunomodulation by 8-week voluntary exercise in mice

This study was designed to evaluate the effects of voluntary exercise on macrophage and lymphocyte functions in mice. Male A/He inbred mice aged 19 weeks were divided into two groups: a group given voluntary exercise and a control group (n = 10 in each group). Exercise consisted of spontaneous running in wheels for 8 weeks (3 days week-1). Glucose consumption of peritoneal macrophages in the exercise group during incubation up to 72 h was significantly higher than that in the control group (70 and 13%, respectively). Also, activities of acid phosphatase (APH) (10.75 +/- 0.37 IU), beta-glucuronidase (GLU) (1.55 +/- 0.07 IU) and lactate dehydrogenase (LDH) (43.3 +/- 0.7 IU) in the peritoneal macrophages in the exercise group was significantly increased (P < 0.01). Compared with the control group, the exercise group had a significant increase of about twofold in macrophage production of nitric oxide (NO2-) stimulated by lipopolysaccharide (LPS) (11.1 +/- 0.1 vs. 5.9 +/- 0.1 microM mL-1 in exercise and control groups, respectively; P < 0.01). Stimulation indices both by concanavalin A (Con A) and phytohaemagglutinin were also significantly higher in the exercise group (P < 0.01). A significant increase in the splenocyte production of interleukin-2 (IL-2) stimulated by Con A was noticed in the exercise group (354.1 +/- 28.8 vs. 218.9 +/- 23.5 pg mL-1 in exercise and control groups, respectively; P < 0.01). These findings suggest that voluntary exercise enhances not only macrophage function but also lymphocyte responsiveness in mice. In the studies of voluntary exercise, evaluation of NO2- production, as an indicator of macrophage function, is recommended.

A four-year follow-up study on subjective symptoms and functional capacities in workers using hand-held grinders

Fifty-three grinders in the metal industry were re-examined 4 years after their first examination. Information about age, occupation, daily vibration exposure, drinking and smoking habits, and presence of subjective symptoms such as vibration-induced white finger (VWF), and numbness and pain in the fingers was collected during the first and second examination. Cold provocation test (10 degrees C/10 min) was also employed to evaluate disturbances in the peripheral circulatory and peripheral nerves in all subjects. The frequency-weighted vibration acceleration of various types of hand-held tools was measured. There was no subject with VWF at the first examination; however, during the course of follow-up, two cases (3.8%) of VWF with latent interval of more than 25 years were diagnosed. Prevalence of numbness in the fingers and shoulder stiffness was significantly higher at the second examination. When the prevalence of subjective symptoms was tested by the subjects' total operating time (TOT) during the 4-year follow-up period, those whose TOT was equal to or more than 2500 hours showed higher prevalence compared to the other subgroup. The paired values of recovery rate of finger skin temperature and vibration sensation threshold after the cold water immersion test were significantly different at the first and second examination. On average, the diminution of hand-grip force during the 4-year follow-up course was 7.4%; the difference being significant at 0.01 level. Significant differences in the paired data of pinching power and tapping ability could be detected. The frequency-weighted vibration acceleration of various tools was in the range of 1.1-4.6 m/s2. It was concluded that: (1) prolonged occupational exposure to the vibration of hand-held grinding tools should be considered as a risk factor causing disturbances in the hand-arm system of the operators; (2) the results of recovery rate of finger skin temperature and the vibration sensation threshold seemed to be appropriate indicators for the assessment of peripheral vascular and peripheral nerve disturbances in workers exposed to hand-arm vibration; and (3) to reduce the subjects' physical stress, attention should be paid to ergonomic factors.

Reduced mastication stimulates impairment of spatial memory and degeneration of hippocampal neurons in aged SAMP8 mice

The involvement of reduced mastication in senile dementia was evaluated by examining the effect of cutting off the upper molars (molarless) on spatial memory and numbers of hippocampal neurons in aged SAMP8 mice. Molarless mice showed a decrease in both learning ability in a water maze and neuron density in the hippocampal CA1 region compared with control mice. These changes increased the longer the molarless condition persisted. The data suggest a possible link between reduced mastication and hippocampal neuron loss that may be one risk factor for senile impairment of spatial memory.

Finger skin temperature and laser-Doppler finger blood flow in subjects exposed to hand-arm vibration

OBJECTIVES

This study was aimed to assess the peripheral circulatory functions of forestry workers exposed to hand-arm vibration, using simultaneous measurements of finger skin temperature (FST) and finger blood flow (FBF).

METHODS

The subjects were five men with vibration-induced white finger (VWF), four subjects with numbness in their hands and five exposed controls without any signs or symptoms related to vibration syndrome. Simultaneous measurements of FST and laser-Doppler FBF were performed before, during and following a 10-min recovery period after the hand was immersed in cold water (10 degrees C, 10 min). Partitional measurements of finger blood flows could be made between the capillaries and deeply located vessels using two laser-Doppler flow probes having narrower and wider optic fiber separations.

RESULTS

The FST as well as the FBF of the capillary and deeply located vessels during and following the cold immersion test in those with VWF and in the subjects with numbness had a slight increase immediately following the cold immersion and no tendency to be augmented as the time span increased. After the cold immersion test, the control group had significantly greater FST and FBF compared to other groups. Particularly, from the 5th to the 10th min after the cold provocation, the values of FBF of the deeply located vessels in those with VWF were significantly lower than the controls. During the course of observation, the FST had significantly linear relationship with the recorded capillary and deep FBF values, and that was much closely correlated with the deep FBF (i.e., P < 0.01 in each selected condition). The slope of the regression lines in the capillary were steeper and shallow in the deep FBF.

CONCLUSIONS

In addition to the measurement of capillary FBF, more detailed and accurate information on the peripheral circulatory functions of vibration-exposed subjects can be obtained by including the assessment of the deep FBF.

Low back pain among different groups of subjects exposed to hand-arm transmitted vibration

OBJECTIVES

The purpose of this study was to investigate the prevalence of low back pain (LBP) among various groups of subjects exposed to hand-arm transmitted vibration, and to compare the prevalence of LBP of these subjects with that of non-exposed groups.

METHODS

The subjects of this study were 13 groups of males and 3 groups of females of working population leaving in a certain city located in the central part of Japan. By means of a questionnaire, interviews, field visits, or annual health examination, information on age, working career, working posture, various types of tools used, and experience of having LBP during the 12 months preceding the completion of the questionnaire were collected. The subjects' age ranged between 22 and 69 years. All subjects were classified into 5 categories, and the prevalence of LBP was obtained for them.

RESULTS

On the whole, complaints of LBP among male and female green tea and strawberry farmers were most frequent. There was a large variation (16.0-72.2%) in the prevalence of LBP among subjects operating vibrating tools. Among three groups of health care professionals, the prevalence of LBP was in the range of 36.5-53.0%. The senior doctors had less complaints of LBP. The prevalence of LBP among subjects who had sedentary jobs was in the range of 41.7-45.9%, and almost as high as that in blue-collar workers using vibrating tools. The prevalence of LBP among females exposed to hand-arm transmitted vibration was between 26.1 and 63%. The prevalence rates of LBP among vibration exposed subjects were plotted against the vibration magnitude of tools used by the same subjects reported in our previous study; however, no significant correlation could be obtained between the prevalence of LBP and vibration values.

CONCLUSIONS

Exposure to segmental vibration is less likely to be a risk factor in increasing prevalence of LBP. A higher prevalence of LBP in some groups provide strong evidence for a dominant work-related etiology in developing LBP. Regarding data presented in this study and by a review on scientific literature, suggestions for improving working posture were presented. It seemed that to decrease the risk of LBP among these subjects, special attention should be paid to stimulating the adoption of an ergonomic working posture and to ergonomic training.

Subjective symptoms among motorcycling traffic policemen

OBJECTIVES

This study investigated the prevalence of subjective symptoms among current and former motorcycling policemen.

METHODS

The subjects of this study consisted of 46 current and 72 former motorcycling traffic policemen from a certain city located in the central part of Japan. They were requested to reply to questions on a self-administered questionnaire regarding age, work history, and subjective symptoms (16 items) during the month preceding the completion of the questionnaire.

RESULTS

Shoulder stiffness and low-back pain were frequently encountered. On the whole, the prevalence of subjective symptoms was higher among the current motorcycling policemen, even though they were younger. Assessing the prevalence of subjective symptoms by the median value of experience of motorcycle riding revealed that the high-exposure subgroup in the group that currently ride motorcycles had higher prevalence rates for all the symptoms.

CONCLUSIONS

The prevalence of subjective symptoms among currently motorcycling traffic policemen seems to be transient, and it declines after the cessation of motorcycle riding or the reallocation to other worktasks, such as office work.

Assessment of hand-arm vibration exposure among traffic police motorcyclists

The aims of this study were (1) to evaluate subjective symptoms in the hand-arm system of all traffic police motorcyclists of a city located in the central part of Japan and (2) to assess their hand-arm vibration exposure associated with traffic police motorcycle riding. The study population consisted of 119 motorcycling traffic policemen and 49 male controls. By means of a questionnaire, information on the occupational history and the presence of subjective symptoms in the hand-arm system of all subjects was obtained. Vibration was measured on the handlebars of the representative motorcycles and on the hands of the riders. The 4- and 8-h energy-equivalent frequency-weighted acceleration as well as the lifetime vibration dose were calculated for all police motorcyclists. The prevalence of finger blanching in the traffic police motorcyclists was 4.2%, but none of the controls had this symptom. The rates of finger numbness (19.3%), finger stiffness (16.0%), shoulder pain (13.4%), and shoulder stiffness (45.4%) were significantly higher among police motorcyclists as compared with controls. The root-mean-square (rms) frequency-weighted acceleration on the handlebars of police motorcycles was in the range of 2.2-4.9 m/s2 rms. The computed 4- and 8-h energy-equivalent frequency-weighted acceleration values were 2.8-4.5 and 2.0-3.2 m/s2 rms, respectively. A pattern of increasing percentage prevalence with increasing cumulative vibration dose was noticed. The subjects with a lifetime vibration dose of more than 20.1 m2 h3 s-4 (in scale) showed significantly higher prevalence rates for symptoms in the fingers and shoulders as compared with the control group. As occupational vibration exposure of traffic police motorcyclists might be considered a risk factor for the development of symptoms in the hand-arm system of the riders, its evaluation and control is needed for prevention methodology evolution.

Proposal for hand-arm vibration exposure limits adopted for Japanese workers operating hand-held vibration tools

On the basis of data presented in our previous, reports, the current study was undertaken to estimate frequency-weighted hand-arm vibration exposure limits for various daily exposure times. The procedures for the present study were as follows. (1) The prevalence of vibration-induced white finger (VWF) as well as the vibration exposure were investigated in various groups of workers operating hand-held vibrating tools. The vibration magnitude of various tools was measured and the results were presented as the energy-equivalent frequency-weighted root-mean-square (m/s2 rms) acceleration. There was a statistically significant positive correlation between the prevalence of VWF and the measured vibration magnitude (R2 = 0.5, P < 0.05). Hence, it was concluded that in decisions concerning quantitative recommendations for vibration exposure, the prevalence of VWF should be considered. (2) By a careful selection of available publications which contain useful information on duration of vibration exposure of < or = 2 h/day and the occurrence of VWF, a significant correlation between the prevalence of VWF and the vibration magnitude could be observed. The regression equation was estimated as: y = -18.5 + 4.6 (x), R2 = 0.8. On the basis of this equation, it was speculated that the prevalence of VWF in workers using vibrating tools might be restricted to the prevalence of Raynaud's phenomenon in the Japanese general population if the 2-h daily vibration exposure is about 4.5 m/s2 rms. (3) Regarding this speculation, the equation provided in the documentation of ISO 5349 was used and modified as: [alpha h,w)eq,t = (alpha h,w)eq,2(2/t)1/2 (m/s2 rms)] and then the vibration limit values for daily exposure of 1 min to 8 h were calculated. (4) In order to achieve compatibility with standards of other countries, and to formulate an easy method for using the recommended values presented here, the daily exposure time of 8, 4, 2, 1 and 0.5 h were selected. The correspondence vibration magnitudes were in the range 22-9.0 m/s2 rms, and the lower limit (2.2 m/s2 rms) was assumed as the permissible vibration exposure limit for an 8-h working period. The proposed daily vibration limits were then compared with those recommended by other institutions.

Some aspects of occupational safety and health in green tea workers

The objectives of this study were to evaluate the health and safety conditions of 36 male and 27 female green tea workers who were aged 40-69 years and had worked for at least 5 years in green tea production procedures. The Mean +/- SD of age was 57.1 +/- 5.8 years in males and 54.4 +/- 6.4 years in females. The mean working career was 26.1 +/- 9.5 years and 24.3 +/- 9.1 years, respectively. The most commonly subjective complaints developed while at work was pain in the lower back at a rate of 72.2% in males and 63.0% in females. Regarding persistent subjective complaints, female workers had significantly (P < 0.05) higher prevalence rate for breath shortness (25.9%) compared to that of male workers (5.6%). It was observed that the male workers whose occupational career was equal to or more than 28 years had significantly higher prevalence rates for stiffness in the neck and pain in the arms, compared to those of male workers whose occupational career was less than 28 years. The prevalence of nasal allergy was 11.1% either in the male or female workers. The total rate of accidents during working hours in the male workers was 22.2%, and that in the female subjects was 18.5%. The mean frequency weighted vibration magnitude produced by using tea-leaf plucker was in the range of 2.4-3.5 m/s2. The mean equivalent A-weighted noise level while using the same equipment was 100.6 +/- 5.0 dB(A). The need for occupational safety and health programs in these small farm settings are discussed.

Operating vibrating tools and prevalence of subjective complaints in vibration syndrome

The aim of this paper is to evaluate the prevalence of subjective symptoms and signs related to vibration syndrome in various groups of subjects exposed to hand-arm vibration (HAV). In 9 groups of subjects occupationally exposed to HAV, one group of subjects previously exposed to HAV, one control group, and 2 groups of general population (males and females), the prevalence of finger blanching, numbness in the hands, stiffness in the hands, and pain in the hands were investigated. The age of subjects ranged from 25 to 59 years. In subjects exposed to HAV, hand-transmitted vibration levels (HTVLs) were measured by means of vibration dosimeters, and the frequency-weighted acceleration levels [(Lh,w)eq,t] were determined as the vibration levels. The prevalence of vibration-induced white finger (VWF) in the exposed subjects was in the range of 0.0-9.6%, and that in subjects who were previously exposed to HAV was 4.1%. The prevalence rates of finger blanching in males and females of the general population were 2.7 and 3.4%, respectively. The highest prevalence rate of VWF was observed among subjects exposed to HTVLs of 2.7-5.1 m/s2. The prevalence of numbness of the hands fluctuated among the groups; i.e., in the exposed groups: in the range of 6.5-30.4%; in those previously exposed to HAV: 16.4%; and was 13.4% in males and 29.5% in females of the general population. The prevalence rates of stiffness in the hands were in the range of 7.6-65.2% in the exposed workers, 13.7% in those previously exposed to HAV, and was 5.5% in males and 20.9% in females of the general population. The prevalence of pain in the hands was between 7.4 and 17.4% in the exposed groups, 1.4% in those who stopped exposure to vibration, and 1.2% in subjects without segmental vibration exposure. Among the subjective symptoms, only VWF showed a significant positive correlation with the measured vibration acceleration; Y = -0.9 + 1.9 X, r = 0.8, P = 0.01. It was concluded that VWF is the most appropriate signs in decisions concerning quantitative recommendations for segmental vibration exposure.

Operating hand-held vibrating tools and prevalence of white fingers

Hand-transmitted vibration levels (HTVLs) and the prevalence of vibration-induced white finger (VWF) and numbness of the hands were investigated in eight groups of subjects operating various hand-held vibrating tools. The prevalence rates of Raynaud's phenomenon (RP) and numbness of the hands in 1,027 males and 1,301 females not occupationally exposed to vibration were compared to those of the exposed subjects. The prevalence of VWF was in the range of 0.0-4.8% in subjects exposed to HTLVs of between 1.1 to 2.5 m/s2 and reached 9.6% in a group of workers exposed to HTLVs of 2.7-5.1 m/s2. The latter group showed a significant difference (P < 0.05) in the prevalence of VWF compared to the 2.7% prevalence of RP in male subjects of the general population. The prevalence of VWF in female subjects exposed to vibration (4.3%) was not significant compared to the prevalence of RP in females of the general population (3.4%). The prevalence rates of numbness of the hands were between 6.5% and 30.4% in the exposed groups and in the range of 13.4-29.5% in the general population. It was concluded that in decisions concerning quantitative recommendations for vibration exposure, the prevalence of VWF should be employed. To decrease the risk of developing VWF, estimated vibration safety values for 4 h and 2 h daily exposures are discussed.

Prevalence of Raynaud's phenomenon in different groups of workers operating hand-held vibrating tools

In eight groups of subjects operating various hand-held vibrating tools and aged from 30 to 59 years, the prevalence rates of vibration-induced white finger (VWF) and numbness, pain, or stiffness in the upper and lower extremities were investigated. Hand-transmitted vibration levels (HTVLs) were measured on the back of the hand, by means of unidirectional (x-axis) vibration dosimeters, and the frequency-weighted acceleration levels [(Lh,w)eq,t] were determined as the vibration levels. The prevalence rates of VWF and numbness of the hands in these subjects were compared to the prevalence rates of Raynaud's phenomenon (RP) and numbness of the hands in 1027 males and 1301 females not occupationally exposed to vibration (age range: 30-59 years). It was observed that in subjects exposed to HTVLs of between 1.1 and 2.5 m/s2, the prevalence of VWF was between 0.0% and 4.8%. The prevalence of VWF reached 9.6% in a group of workers exposed to HTVLs of 2.7-5.1 m/s2. The latter group showed a significant difference (P < 0.05) in the prevalence of VWF compared to the 2.7% prevalence of RP in male subjects of the general population. The prevalence of VWF in female subjects exposed to vibration (4.3%) was not significantly different from the prevalence of RP in females of the general population (3.4%). The prevalence rates of numbness of the hands were in the range of 6.5%-30.4% in the exposed groups and in the range of 13.4%-29.5% in the general population. Among the subjective symptoms, only VWF showed a significant positive correlation with HTVLs (R2 = 0.5, P < 0.05). It was concluded that in decisions concerning quantitative recommendations for vibration exposure, the prevalence of VWF should be employed. With a view to decreasing the risk of developing VWF, estimated vibration safety values for 4 h and 2 h daily exposures are discussed.

Noise in aerobic facilities

Noise levels were evaluated before and during aerobic sessions in 3 aerobic studios. In addition, hearing threshold levels (HTLs) of 10 female aerobic instructors with the mean (+/- SD) ages of 25.4 (+/- 2.4) years were measured before and 2 min after an aerobic session. The mean (+/- SD) of total instruction time of these subjects was 1274.0 (+/- 704.9) h. Before the aerobic session, noise level was 63 dB(A) and increased to 87 dB(A) during a warm-up period. The highest noise levels of 93-96 dB(A) were recorded during a peak exercise period and decreased to 73 dB(A) during a cool-down period. The dominant spectra of sound pressure levels (SPLs) during the aerobic session were in the frequency range of 1-2 kHz at levels of 75-88 dB(C). The mean values of HTL obtained for each ear of these subjects were between 5 and 15 dB in the frequency range of 1-8 kHz. No significant differences in the mean HTLs of pre- and post-aerobic sessions could be obtained. The mean values of HTL of two groups of subjects divided by their total instruction time (n = 5 in each group, and p < 0.01 in their total instruction time) were quite comparable.

Prevalence of Raynaud's phenomenon and specific clinical signs related to progressive systemic sclerosis in the general population of Japan

BACKGROUND

In order to evaluate the prevalence rates of Raynaud's phenomenon (RP) and specific clinical signs related to progressive systemic sclerosis (PSS) in the general population of Japan, inquiries were made concerning RP in the hands and dermatologic examinations were also conducted.

METHODS

One thousand and sixty-three subjects (332 men and 731 women) over 30 years of age who underwent inhabitants' health examinations in 1990 were considered for this study.

RESULTS

The prevalence of RP was 3.0% in men and 3.4% in women. In 8 men and 17 women with RP who received the blood tests, the positive rates of antinuclear antibody (ANA) were 12.5% and 35.3% in men and women, respectively. The prevalence rates of all five specific clinical signs related to PSS, sclerodactyly, pitting scars of the fingers, brown pigmentation of the body, shortened frenulum of the tongue, and flexion contracture of fingers, were under 2% in men and 3% in women. In women with RP the prevalence rates of sclerodactyly, pitting scars of the fingertips, brown pigmentation of the body, and shortened frenulum of the tongue were 16.0, 4.0, 4.0, and 16.0%, respectively. These values were significantly higher than those of persons without RP.

CONCLUSIONS

Because some persons with primary RP may become typical cases of PSS within several years, a followup study, particularly for women who have positive titers of ANA with RP, should be carried out to find out whether the persons suffer from PSS or not.

Cutaneous signs (Raynaud's phenomenon, sclerodactylia, and edema of the hands) and hand-arm vibration exposure

Dermatological tests and examinations of the hand(s) were carried out in vibration-exposed and unexposed males. The subjects were 179 chain-saw workers in private forestry companies and 205 local inhabitants who had never used vibrating tools. The prevalences of Raynaud's phenomenon (RP), sclerodactylia, and edema of the hands were estimated in both groups, and associations between these cutaneous signs and vibration exposure were evaluated. The prevalences of RP and edema in the exposed group were 9.5% and 1.7%, respectively, and in the unexposed group, 2.9% and 1.5%, respectively. Sclerodactylia was seen in 31.8% of the chain-saw workers but in only 6.4% of the unexposed individuals. In statistical analyses based on unconditional logistic regression models with adjustment for age, RP was associated with long-term (> or = 20 years) vibration exposure [odds ratio (OR) = 7.06; 95% confidence interval (CI) = 2.51-19.87]. Sclerodactylia was associated with both short- and long-term vibration exposure (OR = 6.54, CI = 3.30-13.36; OR = 7.05; CI = 3.41-14.60, respectively). There were significant dose-response relationships between RP and duration of exposure and between sclerodactylia and duration of exposure. Results of function tests indicated a longer recovery time and a higher vibration threshold for the workers with RP. The presence of sclerodactylia, however, did not have any significant influence on function test results. It is possible to conclude that not only RP but also sclerodactylia could be induced by vibration exposure. However, most cases of sclerodactylia were not so serious as to involve disturbances of peripheral circulatory and nerve function.

Exposure to segmental vibration and noise in orthopaedists

The results of several field visits to orthopaedic clinics and the data obtained from a postal questionnaire were used to evaluate the segmental vibration and noise exposure levels in orthopaedists. The analysis of 54 (85.7%) complete questionnaires showed that hand-held plaster saws were used (Mean +/- SE, 12.3 +/- 1.7 min/week) more often than other tools. The mean frequency-weighted acceleration levels while using these tools were in the range of 2.3-2.4 m/s2. The A-weighted sound pressure levels in orthopaedic clinics while using the same instruments were in the range of 88.7-93.4 dB(A). Regarding the vibration magnitude and exposure time, segmental vibration seems not to be a serious problem in orthopaedists. However, the noise level produced from operating orthopaedic tools may have deleterious effects such as masking of speech communication among staff members. Patients' sleep or rest was thought to be disturbed by such noise levels.

A survey on noise exposure level in an aluminum can production plant

The present investigation was designed to quantify noise exposure of laborers at various sections of an aluminum can production plant. The acoustic environment in each area was described by sound pressure level (SPL). Decibel (dB) readings were taken for a range of individual frequencies and weighting scales (A and C). Speech interference level (SIL) values for laborers in different production sections were also determined. Moreover, by means of a personal noise dosimetry technique, the equivalent continuous noise exposure level (dB(A)) during an 8-h shift (Leq, 8) was computed. The results obtained were as follows. Spectral analysis of the noise indicated that high SPL associated with high frequency noise exceeded the permissible limit against hearing damage, and it generally amounted to levels higher than 90 dB(A), whereas those inside the control rooms were in the range of 54-60.5 dB(A). Assessment of the results obtained from personal noise dosimeters also revealed that the Leq,8 values were higher than the prescribed limit (85 dB(A)). By preliminary audiometric examinations on the right ears of workers, hearing threshold shifts (HTS) were noticed in the range of 7-11 dB at 1 kHz and 12-16 dB at 4 kHz. With regards to the SIL values (93.2-96.5 dB(A)) which were more than the maximum vocal effort, communication between workers and/or with supervisor were appraised to be very difficult (shouting) or impossible. It was concluded that (a) the dB readings observed in this survey indicate a potentially serious possibility of hearing disability, even though high level of HTS could not be noticed in the preliminary audiometric test, and (b) the risk of accidents should also be taken into account regarding the nonauditory effects of such a high level of noise. We suggest that (1) minimizing the transmission of noise through acoustical countermeasures need to be considered, and (2) introducing a schedule comprising on-time and off-time could be beneficial in a workers' health conservation program.

Hand-arm vibration syndrome and its prevalence in the present status of private forestry enterprises in Japan

Currently there are no limitations on age of employment on private forestries in Japan. Hence, it was hypothesized that in these kind of enterprises, elderly chain saw operators, or those with long-term exposure, might be at higher risk of developing hand-arm vibration syndrome (HAVS). We consequently investigated the prevalence of HAVS in 447 chain saw workers on private forestries in Gifu Prefecture, Japan, with particular reference to age and exposure period. Of this population, 43 (9.6%) had signs and symptoms of vibration-induced white finger (VWF), and among these workers the severity of finger blanching was significantly correlated (P less than 0.01) with the exposure period. Classification of all subjects by exposure period showed that workers with greater than or equal to 30 years' exposure had higher prevalences of VWF (20.9%) and numbness of the hands (25.4%) compared to other groups. Significant differences (P less than 0.01) were found between the functional capacities of workers with VWF and those of control subjects. We concluded that (a) the elderly chain saw operators and those with longer exposure should be moved to other jobs with a lower or no risk of exposure to vibration, and (b) the results of screening tests, even without cold water immersion (which we did not employ, in order to protect workers' hands), could be helpful for the identification of workers with VWF.

[Health condition of female aerobic dance instructors. Subjective symptoms and related factors]

Aerobic dance has recently become popular in all age groups, but the injuries among full-time and part-time aerobic dance instructors have rarely been pointed out in Japan. In this study the subjective symptoms of 63 female instructors in Gifu area were evaluated through health questionnaire. As a control group, 94 female students of the same age group were also included to compare the prevalence of subjective symptoms. Multiple logistic regression analysis was applied to observe the relation between instructors' symptoms and working conditions. The following results were obtained: 1) Complaints of leg and foot pain and laryngeal discomfort were significantly greater in instructors than in students even after adjusting for age and participation in other sports. 2) A significant positive relation was found in instructors between the frequency of dance lessons (times/wk) and various symptoms (calf pain, foot pain, sore throat, and hoarse voice) after adjusting for age and participation in other sports. These results suggest that leg and foot pain and laryngeal discomfort are characteristic symptoms of aerobic dance instructors. Consideration should be made to adjust the frequency of dance lessons in order to reduce these symptoms.

[Differences in the prevalences of Raynaud's phenomenon in general populations living in a mountain area and in a plain area]

Raynaud's phenomenon (RP) which is the episodic and reversible vascular spasm of the extremities can be elicited by cold or emotional changes. RP has been classified into two groups. One is primary Raynaud's phenomenon (PRP) with no identifiable underlying disease and/or cause, and the other is the secondary form of RP (Raynaud's syndrome) with underlying disease and/or cause, e.g., collagen disease, trauma, vibration from vibrating tools, etc. In the present study using this definition of RP the prevalences of RP were studied in general populations in a mountain village "T" and in a town "K" located in a plain area in Gifu prefecture, Japan. The prevalences of RP in T Village were 8.0% (25/314) in males and 3.5% (16/454) in females, and in K Town 2.7% (7/259) in males and 3.2% (21/657) in females. In 52% of the male cases in T Village it was estimated that the exposure to vibration from vibrating tools was the cause of RP. In K Town no male cases of RP were induced by vibration. Exposure to vibration may be one of the important factors when prevalences of RP are investigated in various areas. There were no significant differences between the two areas in the prevalences of PRP (T Village: male 2.9%, female 3.1%; K Town: male 2.7%, female 2.9%). The annual mean air temperature was usually 5-6 degrees C lower in T Village than that in K Town. From the results of this study the differences in the mean air temperature did not appear to have a significant influence on the prevalence of PRP in each area.

[Analysis of subjective symptoms of upper extremities in dental technicians]

Our review of the literature showed no report on the subjective symptoms of the upper extremities in dental technicians. This study was therefore undertaken on 164 dental technicians in Gifu Prefecture to investigate the relationship between the subjective symptoms of the hands, arms and shoulders and work of dental technicians. The following results were obtained. 1) The prevalence of Raynaud's phenomenon and numbness of the fingers was 5.5 and 18.5 %, respectively. A significant positive correlation was observed between the prevalence and frequency of numbness and cold sensation in the fingers and the daily usage time (h) of high-speed type machines. In addition, pain in the fingers and around the wrists, and pain and numbness in the arms were significantly related to the daily usage time (h) of low-speed type machines. These results suggest that the usage of high- and low-speed type machines may be a cause of vibration syndrome among dental technicians. 2) A high prevalence of pain in the shoulders (30.8%), neck (30.1%), and back (36.3%) was observed in dental technicians. It is considered that these symptoms are related to the working posture and usage of machines.

Subjective complaints in orthopedists and general surgeons

The aim of this study was to investigate the prevalence of subjective complaints among two groups of health care personnel. Using a mail questionnaire, 63 male orthopedists and 78 male general surgeons were asked to respond to questions on their subjective musculoskeletal complaints as well as their age, occupational career, and daily working time. In the final analysis, 54 orthopedists and 63 general surgeons who were aged < or = 59 years and had worked for at least 5 years in clinical practice were considered. The mean age was 43.3 (SD 7.6) years for the orthopedists and 41.8 (SD 9.5) years for the general surgeons. Their mean employment time was 18.1 (SD 8.9) years and 16.6 (SD 9.5) years, respectively. The average working time per day was 9.5 h. In general, the orthopedists had a higher prevalence of subjective complaints than the general surgeons. Problems in the shoulders and lower back were the most frequently reported complaints, followed by neck problems. There were significant differences (P < 0.05) between the two groups regarding stiffness in the shoulders, stiffness in the lower back, pain in the neck, and numbness in the fingers. When subjective complaints were compared between the junior (employment time: < 20 years) and senior (employment time: > or = 20 years) staff, the junior orthopedists had significantly higher prevalence rates for stiffness in the shoulders, pain in the neck, and stiffness in the lower back.(ABSTRACT TRUNCATED AT 250 WORDS)