Vibration disease

Influence of 40 Hz and 100 Hz Vibration on SH-SY5Y Cells Growth and Differentiation-A Preliminary Study

(1) Background: A novel bioreactor platform of neuronal cell cultures using low-magnitude, low-frequency (LMLF) vibrational stimulation was designed to discover vibration influence and mimic the dynamic environment of the in vivo state. To better understand the impact of 40 Hz and 100 Hz vibration on cell differentiation, we join biotechnology and advanced medical technology to design the nano-vibration system. The influence of vibration on the development of nervous tissue on the selected cell line SH-SY5Y (experimental research model in Alzheimer’s and Parkinson’s) was investigated. (2) Methods: The vibration stimulation of cell differentiation and elongation of their neuritis were monitored. We measured how vibrations affect the morphology and differentiation of nerve cells in vitro. (3) Results: The highest average length of neurites was observed in response to the 40 Hz vibration on the collagen surface in the differentiating medium, but cells response did not increase with vibration frequency. Also, vibrations at a frequency of 40 Hz or 100 Hz did not affect the average density of neurites. 100 Hz vibration increased the neurites density significantly with time for cultures on collagen and non-collagen surfaces. The exposure of neuronal cells to 40 Hz and 100 Hz vibration enhanced cell differentiation. The 40 Hz vibration has the best impact on neuronal-like cell growth and differentiation. (4) Conclusions: The data demonstrated that exposure to neuronal cells to 40 Hz and 100 Hz vibration enhanced cell differentiation and proliferation. This positive impact of vibration can be used in tissue engineering and regenerative medicine. It is planned to optimize the processes and study its molecular mechanisms concerning carrying out the research.

Vibration in mice: A review of comparative effects and use in translational research

Sound pressure waves surround individuals in everyday life and are perceived by animals and humans primarily through sound or vibration. When sound pressure waves traverse through a solid medium, vibration will result. Vibration has long been considered an unwanted variable in animal research and may confound scientific endeavors using animals. Understanding the characteristics of vibration is required to determine whether effects in animals are likely to be therapeutic or result in adverse biological effects. The eighth edition of the "Guide for the Care and Use of Laboratory Animals" highlights the importance of considering vibration and its effects on animals in the research setting, but knowledge of the level of vibration for eliciting these effects was unknown. The literature provides information regarding therapeutic use of vibration in humans, but the range of conditions to be of therapeutic benefit is varied and without clarity. Understanding the characteristics of vibration (eg, frequency and magnitude) necessary to cause various effects will ultimately assist in the evaluation of this environmental factor and its role on a number of potential therapeutic regimens for use in humans. This paper will review the principles of vibration, sources within a research setting, comparative physiological effects in various species, and the relative potential use of vibration in the mouse as a translational research model.

Ergonomics investigation for orientation of the handles of wood routers

OBJECTIVES

Improperly designed hand tools not only expose workers to potential health risks but also hamper their productivity. This study tries to improve the ergonomics of wood routing tasks, suggesting better handle orientations for hand-held wood routers.

METHODS

Seven different handle combinations were tested over two routing tasks (beading and dado) with regard to perceived discomfort, electromyography (EMG) of biceps brachii and extensor carpi radialis brevis and hand-arm vibrations (HAV).

RESULTS

Handles with 30° and 60° inclinations were found more comfortable than previous 90° handle inclinations for routing tasks. Perceived discomfort in the dado task was found to be significantly higher than in the beading task (p < 0.001); EMG activity also supported this observation. However, EMG data showed no significant difference for the different handles used in the study. No worthwhile reduction was obtained in HAV levels for the modified wooden handles compared to initial plastic handles. Relevance to industry. The ergonomic intervention in wood routers described in this article will contribute to the existing knowledge of ergonomics of handle design and will aid the designers/engineers to design such tool handles that may reduce the risk of work-related musculoskeletal disorders/hand-arm vibration syndrome in workers using wood routers.

Associations between anthropometric factors and peripheral neuropathy defined by vibrotactile perception threshold among industrial vibrating tool operators in Japan

OBJECTIVES

The effect of anthropometric factors on the fingertip vibrotactile perception threshold (VPT) of industrial vibrating tool operators (IVTOs) is not well known. The purpose of this study was to investigate the associations between anthropometric factors and fingertip VPT.

METHODS

We included for analysis two groups of IVTOs: Group 1, predominantly forestry workers (n=325); and Group 2, public servants (n=68). These IVTOs regularly received medical examinations to evaluate hand-arm vibration syndrome. In the examination, measurements of their fingertip VPTs were taken before and after cold-water immersion (10 minutes at 10°C for Group 1 and 5 minutes at 12°C for Group 2). Their body height and weight were measured to calculate the body mass index (BMI). The presence of peripheral neuropathy (PN) was defined as a VPT ≥17.5 dB at 10 minutes after finishing immersion.

RESULTS

In the univariate analysis, weight and BMI were associated with a decreased risk of PN in both Groups 1 and 2. The negative association between BMI and PN remained in the multivariate analysis consistently, but weight reached marginal significance only in the multivariate analysis without BMI in both the groups. Age was positively associated with PN consistently in Group 1 but not in Group 2. Years exposed to vibration showed positive association with PN only in the univariate analysis of Group 1.

CONCLUSIONS

Among IVTOs, factors reflecting body heat production, such as weight and BMI, were associated with a decreased risk of VPT-defined PN, regardless of the task engaged.

An epidemiologic study of carpal tunnel syndrome and hand-arm vibration syndrome in relation to vibration exposure

No Minnesota workers' compensation claims have been filed for permanent partial disability benefits with a diagnosis of hand-arm vibration syndrome (HAVS). A cross-sectional study was undertaken to evaluate 519 compensation claimants following carpal tunnel surgery. Workers with significant vibration exposure and symptoms compatible with HAVS were identified within the group. The results show that some workers are not diagnosed as having HAVS even though they meet the diagnostic criteria. This suggests that HAVS should be considered in the differential diagnosis when a worker presents with neural and/or vascular symptoms of the hands and fingers.

Vibration white finger

Vibration white finger (VWF) occurs in workers who use vibrating tools. On exposure to vibration or cold, patients experience blanching, numbness and pain in the fingers due to exaggerated vasoconstriction. This may involve both central sympathetic hyper-reactivity and local vasoactive factors. In advanced cases, hypertrophy of vascular smooth muscle causes arterial occlusion and ulceration. Diagnostic tests for VWF are unreliable. In early cases, cessation of vibration exposure arrests the progression of disease and may cause symptom remission. Patients with VWF should keep themselves warm, especially their hands, which they should place in warm water at intervals during the day; they should not smoke. Vasoactive drugs may be beneficial in some patients. In the UK, Industrial Injuries Disablement Benefit and compensation are sometimes available. Improved design of tools and restrictions on their operating time have been the main factors leading to a worldwide decline in the incidence of VWF since the early 1970s.

Elevated anticardiolipin antibodies in a patient with vibration-white-finger, valvular heart disease and psoriatic arthritis

We describe a case of irreversible severe vibration-white-finger (VWF) occurring in a male who used a compression-hammer daily at work for a 20-year period. Infra-red thermography following either a cold provocation or a vibratory stress was a sensitive objective method of documenting the condition. Persistent elevation of IgG anticardiolipin antibodies (aCL) was found in his serum and may be a marker of endothelial damage associated with either VWF or the patient's coincidental valvular heart disease.