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PubMed1988

Effects of low- and high-frequency local vibration on the occurrence of intimal thickening of the peripheral arteries of rats.

Rats were exposed to local vibration in a study of the differences in the effects between low and high frequencies of vibration on the vessel wall of peripheral arteries. The vibration was delivered at frequencies of 30 and 480 Hz under a constant acceleration of 5g. The duration of the vibration exposure was 30 d. The changes in the arteries were studied pathohistologically and hematologically. Three of the five rats exposed to 30 Hz and three of the five rats exposed to 480 Hz showed disruption of the internal elastic lamina. The disruption was followed by focal cell proliferation with regenerative formation of collagen and elastic fibers. The vascular changes observed after vibration exposure could not be explained by changes in plasma lipid concentrations. These results suggest that not only low frequencies of vibration, but also high frequencies have harmful effects on the intima of small arteries.

Animals↗
PubMed1987

Prevention of the hand-arm vibration syndrome.

In order to determine the prevalence of the hand-arm vibration syndrome before preventive countermeasures were taken, a special health examination was carried out among 417 national forestry workers operating chain saws in the northern area of Hokkaido, Japan. Thirty-two chain-saw workers (7.7%) were diagnosed as exhibiting the vibration syndrome. The highest prevalence rates were 15.8% among the workers who had operated the saws for 11 to 15 years and 20.3% for workers in their 50s. Improved work conditions for chain-saw workers have increasingly prevented the vibration syndrome in the state forests of Japan since 1978. The present report covered the six years since 1978, and evaluated the effects of these improved work conditions on chain-saw workers from data on the recovery rates of skin temperature and the vibration sense threshold after a cold provocation test. As a result, recovery rates of skin temperature and the vibration sense thresholds at the fifth and tenth minutes after the immersion of the hands in cold water were significantly better than those six years earlier. It is suggested that adequate restrictions on the operating time of the chain saw and on the age of workers can completely prevent the vibration syndrome even if the total operating time is appreciably lengthened.

Adult↗
PubMed1986

Pathophysiological and hygienic aspects of hand-arm vibration.

A review of current knowledge on the pathophysiological and hygienic aspects of the hand-arm vibration syndrome is given. Hemodynamic measurements indicate that the primary factor in vibration-induced white finger is an increase in the peripheral resistance of finger circulation that is present after local and general cooling. The reason for this increase is not known, but it is postulated that an excessive affinity of vasoactive substances for the efferent receptors exists, this affinity being potentiated during local cooling of the digits. So far, the hygienic rating of hazardous vibration in individual work phases is of limited value in diagnosing possible cases, but this rating does provide guidelines for general risk assessment. A consideration of several factors, eg, intermittency of the work, duration of daily exposure, impact of vibration, individual physiological responses, climate, etc, might improve the accuracy of the rating, but the influence of these factors on the development of the vibration syndrome is still poorly understood. Of various preventive measures, only those that significantly reduce vibration will be beneficial in the long run.

Fingers↗
PubMed1983

Platelet function and clotting parameters of vibration-exposed foundry workers.

Platelet aggregation and blood clotting parameters were studied in 22 workers (84 %) using pneumatic riveting and grinding hand tools and in 20 workers (90 %) not exposed to vibration but comparable with respect to age, anthropometric data, smoking and drinking habits, and atherogenic risk factors. The weighted acceleration levels of the vibrating tools are reported. According to Taylor's grading system for vibration-induced white fingers, 15 exposed workers (57 %) were in stage OT, 9 (34 %) in stage 0N, and 1 (4 %) in stage 1. Between the reference and the vibration-exposed groups no differences in the platelet aggregation indices both "in vitro" (adenosine-diphosphate, epinephrine, threshold adenosine-diphosphate concentration) and "in vivo" (platelet factor four, beta-thromboglobulin) were found. In addition the clotting parameters (prothrombin index, activated partial thromboplastin time, fibrinogen, antithrombin III) and the immunoglobulins G, A, and M were normal in the two groups. The measurement of skin temperature of the third right finger before and after the cold provocation test showed that the vibration exposed workers experienced a stronger vasoconstriction of the digital vessels than the referents. It is concluded that, in the early stages of vasospastic disorders, segmental vibration can induce peripheral vascular hyperreactivity without changes in the platelet function and clotting parameters.

Adult↗
PubMed1978

Grip force in vibration disease.

In this experiment the hand grip force of 58 persons was measured. The study was carried out during a compulsory health examination. The subjects compressed with their left hand for 5 min fluctuating maximal force and with their right hand for 1 min with maximal constant force. The results were repeated with five different levels of vibration and without vibration. Individual forces varied in the 5-min experiment from 25 to 122 N. The strongest subjects were in a group affected by white fingers, but with no claim of diminished grip force. The weakest forces were seen in the group subjectively most-affected by vibration disease. On the basis of this examination, it seems that in some workers long-term exposure to vibration causes a diminution in grip force, which is a constant phenomenon, and it does not only manifest itself during their work. During exposure to vibration the force reduced from the resting level among the subjectively most-affected lumberjacks, but not in less-affected groups or in the reference group. No vibration frequency was found to be especially disadvantageous to grip force, and it was not possible to determine the normal limits of grip force.

Adult↗
PubMed2006

Relationship between hand-arm vibration exposure and onset time for symptoms in a heavy engineering production workshop.

OBJECTIVES: This study examined onset time for reported vascular and neurological symptoms in relation to the vibration load in a group of workers exposed to vibration. METHODS: Information on the self-stated year for the first occurrence of symptoms was collected by means of questionnaires. During interviews data were obtained on self-stated estimations of daily exposure time, type of tool, and number of months or years with different exposures. The estimations of the vibration magnitudes of exposure were based on conducted measurements. From these data, the individual vibration exposure at the time of onset of symptoms was calculated. RESULTS: The incidence was 25.6 and 32.9 per 1000 exposure years for vascular and neurological symptoms, respectively, in the group of workers. The first onset of symptoms appeared after an average of 12 years of exposure. For the workers, the symptoms of vascular or neurological disorders started after about the same number of exposure years. The calculated accumulated acceleration correlated best with the onset time of symptoms. CONCLUSIONS: It was concluded that, since the workers' exposure to vibration was below the action level established in the European vibration directive, the results suggest that the action level is not a safe level for avoiding vascular and neurological symptoms.

Arm↗
PubMed1998

[Validation of dissolution testing: evaluation of vibration levels of dissolution apparatuses].

The collaborative study participated by seven laboratories was carried out to develop a dissolution standard for evaluating vibration levels of dissolution apparatuses using enteric-coated granules of cefalexin (EG). Dissolution apparatuses could be divided into two groups according to their vibration levels and the dissolution test results of EG by the rotating basket method at 50 rpm. The critical value of acceleration was about 0.05 m/s2. The upper limit of normal dissolution rates of EG was calculated from the results of the rotating basket method at 50 rpm obtained from low vibration apparatuses. All high vibration apparatuses used in this study were distinguished by the limit from low vibration apparatuses, although most of them were not distinguished by current USP calibrators. These results suggest that EG would be useful as a calibrator for detection of apparatuses on high vibration levels.

Calibration↗
PubMed1976

[State of regional hemodynamics in patients with vibration disease during sanatorium treatment (reographic studies)].

The state of the regional haemodynamics was studied in 216 patients with vibration disease kept on balneologic therapy. Vibration disease was the result of "local" vibration in 104 patients, and that of combined vibration -- in 112. Rheographic studies of the peripheral blood flow demonstrated disorders of the regional haemodynamics in 76% of the patients, their severity depending on the stage of the pathological process. Rheogrammes recorded during spontaneous attacks of angiospasm or following a cold test revealed a distinct, sometimes complete levelling of the rheographic elements predetermined by the angiospastic state of the peripheral vessesl. The revealed changes in the functional state of the regional flow were of a similar angiospastic nature and reflected the severity of the pathological syndrome, as well as the site of the prevailing vibration effect. Dynamic rheographic studies conducted in patients following balneological treatment (nitrogen-thermal or bromiodine baths) revealed positive changes in the qualitative and quantative rheographic parameters indicating normalization or improvement of the peripheral circulation in vibration disease cases. A comparative assessment of the immediate therapeutic effect of the balneological treatment demonstrated more distinct positive shifts in the rheographic parameters of the regional haemodynamics following a course of nitrogen-thermal baths.

Fingers↗
PubMedDate not supplied

[The hand-arm vibration syndrome: (II). The diagnostic aspects and fitness criteria].

Part II of this paper reviews the clinical and laboratory methods to diagnose the neurological, vascular and osteoarticular components of the hand-arm vibration syndrome. The prognosis and reversibility of vibration-induced neurological and vascular disorders after cessation of vibration exposure or the introduction of powered tools equipped with vibration isolation systems are discussed on the basis of the results of follow-up clinical investigations and longitudinal epidemiologic studies. Finally, the review debates some of the methodological aspects connected with the health surveillance of vibration-exposed workers and considers the possible medical contra-indications for prolonged exposure to hand-transmitted vibration.

Arm Injuries↗
PubMed1975

[Cellular responses to vibration during dental drilling with belt drive motor engine (in vitro) (author's transl)].

There have been many reports on the pulpal reaction caused by vibration during high speed dental drilling with air turbine hand-piece. It is, however, not clear pulpal responses to vibration of low speed drilling with 7 000 rpm of belt drive motor engine which produces a fundamental vibration of about 170 cps having most unpleasant sensation at vestibular apparatus. Here, cellular responses of L strain cells to vibration derived from 7 000 rpm and 15 000 rpm of belt drive motor engine were observed in vitro system. There is no difference between the both cellular responses to the vibration of 7 000 rpm and 15 000 rpm. Suspended free cells were easily influenced and degenerated by the vibration, and remarkably checked in their cell-multiplication. On the contrary, in the cells adhered to the substratum of glassware, no degeneration and no inhibitory effect were observed. And the cells showed reversible response of cytoplasmic shrinkage only.

Cell Adhesion↗
PubMed2001

Biosynthetic response of cultured articular chondrocytes to mechanical vibration.

The objective of this study was to determine the effects of mechanical vibration loading on DNA and proteoglycan syntheses in cultured rabbit articular chondrocytes. Chondrocyte culture plates were placed in a vibratory apparatus and subjected to a mechanical vibratory load at various frequencies and periods in culture. Mechanical vibration was applied at a sinusoidal waveform of 1.4 g acceleration with frequencies of 200, 300, 400, 800, and 1600 Hz. 3H-Thymidine and H2(35)SO4 incorporation were used to detect radiolabeled DNA and proteoglycan syntheses, respectively. A frequency of 300 Hz showed a time-dependent augmentation of DNA synthesis and gave a maximal increase at day 3 with periodic vibration (8 h per day) and at 72 h or longer with continuous vibration. It also promoted proteoglycan synthesis in long-term culture (from 3 to 15 days) by periodic vibration. However. frequencies above 400 Hz suppressed biosynthesis. These results suggest that mechanical vibration at certain frequencies may modulate biosynthetic response of articular chondrocytes.

Animals↗
PubMed1998

[Effects of whole-body vibration on human tracking performance and visual-motor reaction].

Dual task test (light target tracking and visual-motor reaction of visual oddball mode) and pursuit aiming test were done in 17 male healthy subjects after 30min exposure to whole-body vibrations of 20 Hz 0.15 gz or 20 Hz 0.3 gz. Mean accuracy rate of visual-motor reaction and target stimulus reaction accuracy rate after 0.3 gz vibration were significantly lower than those of control group (P < 0.05), while after 0.15 gz vibration, the changes were not significant. Comparing with control group, the total number of right and wrong pointing, pointing speed in pursuit aiming test were significantly lower (P < 0.05) after vibration. However, light target tracking error, mean reaction time of visual-motor reaction and pointing accuracy rate of pursuit aiming test had no significant change after exposure to any kind of the vibrations. It may be concluded that some kinds of effect on human tracking performance and visual-motor reaction were observed after exposure to whole-body vibration.

Adult↗
PubMed2000

The vibration analysis of obturator framework designs.

The purpose of this study was to analyze the vibration of obturator framework designs and investigate the vibration effects of connecting parts of the components. Four designs of maxillary obturator framework were used in this study: a partial palatal plate with continuous bar (A), with a part of continuous bar (B), without continuous bar (C) and without continuous bar and indirect retainer (D). In order to investigate the vibration of each framework (total) and some component parts, the measurement points of the retentive parts were divided into 3 groups; anterior, middle and posterior. The framework was activated by a vibration generator. The vibration of each measurement point was detected with a laser doppler vibrometer. The frequency response signals were conducted by an FFT Analyzer between 220-2000 Hz. The maximum displacement (MDP) and the decay rate (DR) of the vibration were analyzed statistically by ANOVA and Fisher's PLSD (p<0.05). The result showed that in the posterior group, MDP of D was higher than those of A, B and C. Regarding the anterior, middle and total group, the DR of D were lower than A, B and C. It was suggested that D might be clinically unfavorable.

Analysis of Variance↗
PubMed2002

[Prevention of hand-arm vibration syndrome by using antivibration gloves].

Hand-arm vibration syndrome induced by the exposure to mechanical vibration transmitted from power tools to the operator's hands contributes highly to the number of occupational diseases certified in Poland, as well as in other countries. Use of antivibration gloves is one of the methods for reducing the occupational risk of vibration damages. However, the number of researchers express certain reservations about the benefits from wearing such a protective device, mostly because of very limited scientific and explicit evidence to prove the effectiveness of antivibration gloves in preventing hand-arm vibration syndrome. But there is no controversy about the opinions that to achieve a maximum degree of protection, antivibration gloves should be selected to match particular vibratory tools, taking account of the vibration spectrum generated, by them. The paper presents the general principles of the glove selection, the results of the studies of the effectiveness of antivibration gloves carried out by the Central Institute for Labour Protection (CIOP), as well as some other results, opinions and ideas. The gathered data prove that antivibration gloves are a useful measure to prevent hand-arm vibration syndrome.

Arm Injuries↗
PubMed2001

[Study on vibration mode of different phonatory source and compensation after partial laryngectomy].

OBJECTIVE: To investigate the nature of pathological voice production and compensatory mechanism after partial laryngectomy. METHODS: Vocal function of 93 cases following partial laryngectomy (28 cases of horizontal partial laryngectomy, 35 vertical partial laryngectomy, 30 horizontal-vertical partial laryngectomy) were examined by acoustic analysis, aerodynamic analysis and videostroboscopic examination. RESULTS: Horizontal supraglottic laryngectomy(HL) resulted in slight dysphonia after operation. The cover of vocal fold was hypertrophic and edematous. Mucosa wave was increased. Acoustic analysis showed significant difference between normal and horizontal laryngectomy groups(P < 0.05). Vertical laryngectomy(VL) resulted in moderate-severe dysphonia. Acoustic analysis was significantly worse in VL than in normal group(P < 0.01). The nonglottic phonatory source was the contralateral ventricular fold or contralateral vestibular mucosa (arytenoid mucosa, root mucosa of glottis) to approximate the reconstructed flap. It was noted that contralateral vocal fold did not participate in vibration. Horizontal-vertical partial laryngectomy (HVL) resulted in moderate-severe dysphonia. Acoustic analysis of HVL was significantly worse than that of normal phonation(P < 0.01). The site of compensatory mucosa vibration upon phonation was the contralateral vocal fold or contralateral hypertrophic arytenoid mucosa. The thinner the flap, the better the vocal quality was. Vocal quality of VL was worse than that of HVL in regard to shimmer, jitter, normalized noise energy, maximal phonation time and harmonic-noise ratio, but there was no significant difference between them. CONCLUSIONS: Partial laryngectomy has different vibrating compensatory modes: Voice function of horizontal partial laryngectomy was the best as it preserved the normal vibration mode; vertical partial laryngectomy was the worst with the nonglottic vibrating source of reconstructed flap-ventricular fold. The reconstructed flap, ventricular fold, mucosa of epiglottis and arytenoid take predominantly part in neoglottal vibration. The situation, volume and pliability characteristic of reconstructed flap was also important to vocal quality.

Aged↗
PubMed2003

Diagnosis and treatment of hand-arm vibration syndrome and its relationship to carpal tunnel syndrome.

BACKGROUND: Hand-arm vibration syndrome (HAVS) is a condition associated with the use of vibrating tools that occurs mainly in men. It consists primarily of 'occupational' Raynaud disease and digital polyneuropathy. Carpal tunnel syndrome (CTS) is also associated with hand transmitted vibration exposure and can coexist with HAVS. OBJECTIVE: This article examines recent papers on causation, diagnosis, relationship to CTS and treatment. A Medline search was conducted, as was a search of UK, USA and Australian government occupational health and safety websites. Published papers that were single case studies or of poor design were not included. DISCUSSION: There are no 'gold standard' diagnostic tests for HAVS. It can mimic CTS in temperate climates and can occur with CTS. This is the diagnostic challenge when a male worker presents with apparent CTS symptoms. If he has worked with vibrating tools for many years, a diagnosis of HAVS or co-diagnosis of HAVS should be considered before a diagnosis of pure CTS is made. Nonwork risk factors for HAVS are predisposition, smoking, and exposure to vibration outside work. Cessation of exposure (and smoking) and redeployment is a critical part of treatment due to the dose response relationship of HAVS. This contrasts with adequately treated CTS, where the vast majority of workers can return to pre-injury duties. In severe cases, calcium antagonists are also used, but treatment is often ineffective. Few workplaces in Australia manage vibration risk or conduct screening to identify workers with early HAVS who should be redeployed. Local doctors have an important opportunity to diagnose HAVS and to make recommendations to the workplace on redeployment as part of treatment before symptoms become irreversible.

Arm↗
PubMed2003

Effect of ultrasonic vibration on dentin bond strength and resin infiltration.

PURPOSE: To apply a vibration technique to compare the bond strength and resin penetration depth into the dentin tubules with those gained using conventional techniques. METHODS: Eighty-eight noncarious extracted human permanent molar teeth were sectioned to remove the coronal enamel. They were embedded in a 1-inch PVC pipe with an acrylic resin. The occlusal surfaces were placed so that the tooth and the embedding medium were at the same level to form a single flat surface. The samples were subsequently polished with silicon carbide abrasive papers, and randomly assigned to four groups (n=22). In Groups 1 and 2, Single Bond was used, and in Groups 3 and 4, One-Step was used. Each adhesive system was applied according to its manufacturer's instructions. For Groups 2 and 4, vibration was applied with an ultrasonic scaler for 10 seconds, and the adhesive was light-cured for 10 seconds. The resin composite was condensed onto the prepared surface in two increments using a Teflon mold and each increment was light-cured for 40 seconds. After 24 hours soaking in tap water at room temperature, the specimens were thermocycled, and the shear bond strengths were measured using a universal testing machine. One-way ANOVA test followed by Student-Newman-Keuls test (P < 0.05) were used to analyze the results. To investigate the infiltration patterns of the adhesive materials, the surface of the specimens was examined with electron microscopy. RESULTS: The shear bond strengths of the vibration groups (Groups 2, 4) were significantly higher than those of the non-vibration groups (Groups 1, 3). The shear bond strengths of Single Bond and One-Step were not significantly different. The vibration groups showed greater numbers of resin tags in the tubules and lateral branches under SEM than the non-vibration groups.

Analysis of Variance↗
PubMed2005

Correlation between mechanical vibration analysis and dual energy X-ray absorptiometry (DXA) in the measurement of in vivo human tibial bone strength.

It is assumed that bone mineral density (BMD) measurement by dual-energy X-ray absorptiometry (DXA) has its limitation in identifying bone strength, and therefore other methods should be developed. Non-invasive strength measurement, which is needed to diagnose and monitor metabolic bone diseases such as osteoporosis, can become an alternative to current methods. In this study, mechanical vibration analysis was compared to BMD measured by DXA in human female tibia. Seven mother (Ms) and daughter (Ds) pairs' (total n = 14) left and right tibiae were evaluated by DXA and mechanical vibration analysis. Mechanical vibration analysis was consistent in the same bone and also in both sides. Correlation between BMD measured by DXA and vibration analysis was found in the Ds and Ms groups; the former being stronger than the latter. Natural frequencies of the Ms group were higher than that of the Ds group, and the response velocity of the Ds group was shorter than that of the Ms group. It is concluded that mechanical vibration analysis is consistent in bones and a correlation between BMD measured by DXA and vibration analysis can be established in young females that may be used in field studies to predict peak bone strength.

Absorptiometry, Photon↗