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At least 235 records · Page 13Linked to original sources
PubMed1998

A biomechanical study of occupational loads in the shoulder and elbow in dentistry.

OBJECTIVE: The aim was to demonstrate that when electromyographic (EMG) recordings are supplemented by biomechanical calculations more detailed information on shoulder loads are produced. DESIGN: Shoulder and elbow moments were calculated for three work situations of arm abduction (> 30 degrees, < 30 degrees and < 30 degrees with force on the hand) and were related to EMG. BACKGROUND: Prolonged arm elevation may result in shoulder pain and information on shoulder loads is needed to avoid development of musculoskeletal disorders. METHODS: Three-dimensional coordinates from video recordings of eight working dentists were used in a static link segment model based on orthopaedic axes. Moments and EMG (trapezius muscle) were related. Results: Working with the upper arm abducted more than 30 degrees produced 1.7 Nm (440%) higher moments of shoulder abduction, 0.5 Nm (100%) higher moments of outward upper arm twisting and 0.3 Nm (18%) smaller moments of elbow flexion than working with the upper arm abducted less than 30 degrees. Trapezius muscle activity did not increase with increased arm abduction. Force on the hand (20 N) recorded during cavity filling altered moments of the shoulder and elbow but not the activity level of the trapezius muscle. CONCLUSION: Supplementing EMG with biomechanical calculations of moments results in more detailed information on shoulder loads. This is important for over-all risk identification.

Journal Article↗
PubMed2001

Influence of memory demand and contra lateral activity on muscle activity.

Computer mouse work often includes memory demands and contra lateral activity. This study simulated video display unit (VDU) mouse-work and the focus was on forearm muscle activity as a result of standardised postural loads, memory demands and contra lateral activity. Surface and intramuscular electromyography (EMG) were recorded from the right forearm muscles during finger elevation and rest with and without memory demands and with and without contra lateral activity i.e. activity of the left hand. In most situations, memory demand increased activity in the m. extensor carpi radialis brevis and m. flexor digitalis superficialis. Also contra lateral activity increased activity in situations with and without memory demands. While surface EMG level of the m. extensor digitorum communis did not increase during memory demands, intramuscular EMG level increased when memory demands and contra lateral activity was combined. Influence of memory demands and contra lateral activity were most pronounced, in situations where activity levels were small. We presume that it is not only prolonged time of active computer mouse use that is a risk for development of musculoskeletal disorders, but also the time when people interact with the computer mentally or with the 'non-mouse hand', while resting their 'mouse-hand' on the mouse.

Adult↗
PubMed2002

Marimastat as maintenance therapy for patients with advanced gastric cancer: a randomised trial.

This randomised, double-blind, placebo-controlled study was designed to evaluate the ability of the orally administered matrix metalloproteinase inhibitor, marimastat, to prolong survival in patients with non-resectable gastric and gastro-oesophageal adenocarcinoma. Three hundred and sixty-nine patients with histological proof of adenocarcinoma, who had received no more than a single regimen of 5-fluorouracil-based chemotherapy, were randomised to receive either marimastat (10 mg b.d.) or placebo. Patients were treated for as long as was tolerable. The primary endpoint was overall survival with secondary endpoints of time to disease progression and quality of life. At the point of protocol-defined study completion (85% mortality in the placebo arm) there was a modest difference in survival in the intention-to-treat population in favour of marimastat (P=0.07 log-rank test, hazard ratio=1.23 (95% confidence interval 0.98-1.55)). This survival benefit was maintained over a further 2 years of follow-up (P=0.024, hazard ratio=1.27 (1.03-1.57)). The median survival was 138 days for placebo and 160 days for marimastat, with 2-year survival of 3% and 9% respectively. A significant survival benefit was identified at study completion in the pre-defined sub-group of 123 patients who had received prior chemotherapy (P=0.045, hazard ratio=1.53 (1.00-2.34)). This benefit increased with 2 years additional follow-up (P=0.006, hazard ratio=1.68 (1.16-2.44)), with 2-year survival of 5% and 18% respectively. Progression-free survival was also significantly longer for patients receiving marimastat compared to placebo (P=0.009, hazard ratio=1.32 (1.07-1.63)). Marimastat treatment was associated with the development of musculoskeletal pain and inflammation. Events of anaemia, abdominal pain, jaundice and weight loss were more common in the placebo arm. This is one of the first demonstrations of a therapeutic benefit for a matrix metalloproteinase inhibitor in cancer patients. The greatest benefit was observed in patients who had previously received chemotherapy. A further randomised study of marimastat in these patients is warranted.

Adenocarcinoma↗
PubMed2006

Effects of electromyographic and mechanomyographic biofeedback on upper trapezius muscle activity during standardized computer work.

The purpose of this laboratory study was to investigate the effects of surface electromyography (EMG)- and mechanomyography (MMG)-based audio and visual biofeedback during computer work. Standardized computer work was performed for 3 min with/without time constraint and biofeedback in a randomized order. Biofeedback was given on the basis of an individual preset threshold value for the right trapezius EMG and MMG signal and a time factor (repetition of events above the threshold). The duration of muscle activity above the preset threshold, the right trapezius EMG and MMG root mean square (RMS) values as well as the work performance in terms of number of completed graph/mouse clicks/errors, the rating of perceived exertion (RPE) and the usefulness of the biofeedback were assessed. The duration of muscle activity above the threshold was significantly lower with MMG compared with EMG as source of biofeedback (p < 0.05). Biofeedback led to a significant decrease in the right trapezius EMG RMS, lower RPE and decreased number of errors and mouse clicks, but also decreased number of completed graphs (p < 0.05). Audio and visual biofeedbacks were as effective. MMG-based biofeedback is a potential reliable alternative to EMG in ergonomics. A lowering of the trapezius muscle activity may contribute to diminish the risk of work related musculoskeletal disorders development.

Adult↗
PubMed1995

Quantification of the static load component in muscle work using nonlinear filtering of surface EMG.

Prolonged static strain on the muscles of the neck-shoulder region is believed to be linked to the development of musculoskeletal problems. To quantify the static strain on the basis of EMG, the level as well as the duration of the muscle load should be analysed on temporal basis. In this paper, some methods for the temporal analysis of EMG recordings are proposed with an aim of quantifying the long-term static strain on the muscle. The use of nonlinear median prefilters for decomposing the EMG activity according both to amplitude level and duration of the activity at different levels is proposed. The prefiltering methods were also evaluated using laboratory studies. The main aim of the studies was to compare the estimation errors between EMG and force for different types of prefilters especially when the static load component was analysed. The average estimation error for sequences having a duration longer than 1 s was found to be 8% of MVC in the case of trapezius muscle and 14% of MVC in the case of biceps brachii muscle. Linear relation was found on the basis of linear least squares curve fitting to give the largest correlation coefficients between EMG and force, when the static load component was analysed.

Adult↗
PubMed2003

An ergonomics process for the care and use of research animals.

Personnel who work with laboratory animals incur potential occupational health risks that can lead to the development of musculoskeletal disorders. Demanding manual tasks may also result in increased errors, worker fatigue, poor human performance, and decreased productivity. Studies have shown that a comprehensive ergonomics program that utilizes a systematic risk management approach can reduce the likelihood of exposure to musculoskeletal disorder risk factors and remove barriers to human performance. Research has characterized the risk factors of musculoskeletal disorder exposure in terms of force, frequency, posture, and muscle exertion. Ergonomic risk factors for typical animal handling tasks and work areas are identified, and a method is suggested for prioritizing interventions using interrelated data indicators. An initial review of potential control measures is offered to improve the health, safety, and effectiveness of people involved in the care and use of research animals.

Animal Experimentation↗
PubMed1989

Effect of overuse injury and the importance of training on the use of adjustable workstations by keyboard operators.

The introduction of adjustable workstations for keyboard operators has been widely recommended to eradicate constrained working postures leading to the development of musculoskeletal disorders. A questionnaire evaluating the use of adjustable workstations was analyzed for 514 keyboard operators. Anthropometric dimensions and workstation settings were measured for 15 operators. There was no difference between sufferers and nonsufferers of overuse injury on the basis of adjustability of their equipment. However, sufferers were less satisfied with their equipment and there was evidence that inappropriate postures were being adopted. The availability of adjustable equipment per se does not necessarily solve the problem. The design of the equipment must be based on suitable anthropometric data and operators must be trained in the correct use of the equipment. The results of this study indicate a perceived need for training and/or information on workstation adjustment among operators, with a preference for information that is supplied verbally, rather than in literature form.

Anthropometry↗
PubMed1992

Standardised method of follow-up assessment of preterm infants at the age of 5 years: use of the WHO classification of impairments, disabilities and handicaps. Report from the collaborative Project on Preterm and Small for gestational age infants (POPS) in The Netherlands, 1983.

A nationwide, prospective study was initiated in The Netherlands in 1983, involving 1338 liveborn infants with a gestational age less than 32 weeks and/or a birthweight less than 1500 g. Pre- and perinatal data, methods and results of follow-up until the corrected age of 2 years have been published previously. In this paper, methods of follow-up at the age of 5 years are described. At that age, 966 children were alive, of which 927 (96%) were assessed during a home visit 2 to 6 weeks after their fifth birthday by three specially trained paediatricians. A questionnaire served to collect data on medical history, respiratory function, behaviour and socio-economic factors. Standardised tests were carried out covering the following 10 areas: congenital malformations, neuromotor function, mental development, hearing, visual function, language and speech development, behaviour, musculoskeletal system, respiratory tract and ENT problems, and growth. The outcome was recorded for separate areas and for the child as a whole using the WHO classification of impairments, disabilities and handicaps.

Abnormalities, Multiple↗
PubMed2001

Cancer and autoimmunity: autoimmune and rheumatic features in patients with malignancies.

OBJECTIVES: To review the autoimmune and rheumatic manifestations of patients with malignancy. METHODS: A Medline search of all published papers using keywords related to malignancies, autoimmunity, rheumatic diseases, and paraneoplastic syndromes. RESULTS: Patients with malignant diseases may develop autoimmune phenomena and rheumatic diseases as a result of (a) generation of autoantibodies against various autoantigens, including oncoproteins (P185, 1-myc, c-myc, c-myb), tumour suppression genes (P53), proliferation associated antigens (cyclin A, B1, D1, E; CENP-F; CDK, U3-RNP), onconeural antigens (Hu, Yo, Ri, Tr), cancer/testis antigens (MAGE, GAGE, BAGE, SSX, ESO, SCP, CT7), and rheumatic disease associated antigens (RNP, Sm). The clinical significance of the various autoantibodies is not clear. Anti-oncoprotein and anti-tumour suppression gene antigens are detected before the diagnosis of the cancer or in the early stages of the malignant disease, suggesting a potential diagnostic or prognostic role. Anti-onconeural antibodies are pathogenic and are associated with specific clinical neurological syndromes (anti-Hu syndrome and others). (b) Paraneoplastic syndromes, a wide range of clinical syndromes, including classic autoimmune rheumatic diseases that develop among patients with cancer. (c) Rheumatism after chemotherapy, a clinical entity characterised by the development of musculoskeletal symptoms after combination chemotherapy for malignancy. CONCLUSION: Autoimmune and rheumatic features are not rare among patients with malignancies. They are the result of various diverse mechanisms and occasionally they may be associated with serious clinical entities.

Antibodies, Antinuclear↗
PubMed2005

Effect of vitamin D replacement on musculoskeletal parameters in school children: a randomized controlled trial.

BACKGROUND: Despite the high prevalence of hypovitaminosis D in children and adolescents worldwide, the impact of vitamin D deficiency on skeletal health is unclear. METHODS: One hundred seventy-nine girls, ages 10-17 yr, were randomly assigned to receive weekly oral vitamin D doses of 1,400 IU (equivalent to 200 IU/d) or 14,000 IU (equivalent to 2,000 IU/d) in a double-blind, placebo-controlled, 1-yr protocol. Areal bone mineral density (BMD) and bone mineral content (BMC) at the lumbar spine, hip, forearm, total body, and body composition were measured at baseline and 1 yr. Serum calcium, phosphorus, alkaline phosphatase, and vitamin D metabolites were measured during the study. RESULTS: In the overall group of girls, lean mass increased significantly in both treatment groups (P < or = 0.05); bone area and total hip BMC increased in the high-dose group (P < 0.02). In premenarcheal girls, lean mass increased significantly in both treatment groups, and there were consistent trends for increments in BMD and/or BMC at several skeletal sites, reaching significance at lumbar spine BMD in the low-dose group and at the trochanter BMC in both treatment groups. There was no significant change in lean mass, BMD, or BMC in postmenarcheal girls. CONCLUSIONS: Vitamin D replacement had a positive impact on musculoskeletal parameters in girls, especially during the premenarcheal period.

Adolescent↗
PubMed2006

The effect of endurance exercise on the morphology of muscle attachment sites.

The morphology of muscle attachment sites, or entheses, has long been assumed to directly reflect in vivo muscle activity. The purpose of this study is to examine whether variations in muscle activity that are within normal physiological limits are reflected in variations in external attachment site morphology. This study tests the hypothesis that increased muscle activity (magnitude, number and frequency of loading cycles) results in the hypertrophy of muscle attachment sites. The attachment sites of six limb muscles and one muscle of mastication (control) in mature female sheep were measured and compared in exercised (weighted treadmill running for 1 h per day for 90 days) and sedentary control animals. Attachment site surface morphology was assessed by quantifying the size (3D surface area) and complexity (fractal dimension parallel and perpendicular to soft tissue attachment) of the surfaces. The results of this study demonstrate no effect of the exercise treatment used in this experiment on any measure of enthesis morphology. Potential explanations for the lack of exercise response include the mature age of the animals, inappropriate stimulus type for inducing morphological change, or failure to surpass a hypothetical threshold of load for inducing morphological change. However, further tests also demonstrate no relationship between muscle size and either attachment site size or complexity in sedentary control animals. The results of this study indicate that the attachment site morphological parameters measured in this study do not reflect muscle size or activity. In spite of decades of assumption otherwise, there appears to be no direct causal relationship between muscle size or activity and attachment site morphology, and reconstructions of behavior based on these features should be viewed with caution.

Aging↗
PubMed1994

Physical activity and training: effects on stature and the adolescent growth spurt.

Statural growth (size attained), age at peak height velocity (PHV), and growth rate were compared in two samples of boys classified as habitually physically active and inactive, and in two samples of boys regularly training in sport (primarily team sports). Individual growth records were fitted mathematically in three of the samples (two as reported by the respective authors and one for the present report), while curves were fit to group means for the fourth sample. There were no differences in size, age at PHV, and PHV between active and inactive boys, but the parameters of the adolescent spurt for boys regularly involved in sport were characteristic of early maturers. Longitudinal data are less extensive for girls. Stature data for three samples of young athletes in gymnastics, swimming, and track/rowing indicated a stable pattern relative to reference data for nonathletes, i.e., swimmers, track athletes, and rowers were already taller and gymnasts already shorter than average during childhood and maintained their position relative to reference data during childhood and adolescence. Allowing for sample size and variation in descriptions of habitual physical activity and training for sport, the data suggest that regular physical activity, sport participation, and training for sport have no effect on attained stature, timing of PHV, and rate of growth in stature. Prospective data for the swimmers, track athletes, and rowers indicate no effect of training on the timing of menarche.

Adolescent↗
PubMed2000

A 37-year-old mechanic with multiple chemical sensitivities.

A 37-year-old heating, ventilation, and air-conditioning mechanic developed respiratory, musculoskeletal, and central nervous system symptoms associated with a variety of odorous environmental chemicals. Organic disease was not evident, but the patient was distressed by these symptoms and was at risk for becoming disabled by them. His symptoms fit broadly into the condition recognized as multiple chemical sensitivity. Multiple chemical sensitivity is a diagnostic term for a group of symptoms without demonstrated organic basis. The symptoms are characteristic of dysfunction in multiple organ systems, they increase and decrease according to exposure to low levels of chemical agents in the patient's environment, and they sometimes occur after a distinct environmental change or insult such as an industrial accident or remodeling. Although traditional medical organizations have not agreed on a definition for this syndrome, it is being increasingly recognized and makes up an increasing percentage of the caseload at occupational and environmental medicine clinics. Although there is often dispute about whether the symptoms have a functional or organic basis, an informed approach to evaluation, diagnosis, and management and a careful assessment of impairment, disability, and work relatedness are necessary. Careful exclusion of organic causes is critical, and this should be followed by a judicious approach to coping with symptoms.

Adaptation, Psychological↗
PubMed2005

Rupture of the gastrocnemius muscle in six foals.

Rupture of the gastrocnemius muscle and subsequent disruption of the reciprocal mechanism of the hind limb was diagnosed in 6 foals examined at 7 hours to 3 weeks of age. In 2 foals, the musculoskeletal injury was detected as an ancillary finding to clinical signs of neurologic dysfunction ascribed to hypoxic ischemic insult during delivery, whereas in the other 4 foals, musculoskeletal injury, manifested as inability to rise or stand unsupported, was the chief complaint at admission. Five foals had a history of dystocia and assisted delivery. Common clinical signs were inability to rise, disruption of the reciprocal mechanism, swelling in the caudal aspect of the thigh, instability of the stifle joint, and stifle joint effusion. For mild gastrocnemius injury, exercise restriction via forced recumbency, with minimal or no bandaging, may be sufficient treatment. For more severe disruption of the muscle, limb stabilization via splinting and intensive nursing and monitoring are necessary. Four foals had important concurrent problems, including musculoskeletal deformations (joint contractures), hypoxic ischemic disease, and failure of passive transfer and associated problems (ie, sepsis, polyarthritis, and pneumonia). Moderate to severe gastrocnemius muscle injury is difficult to treat successfully, and the long-term prognosis for athletic function should be regarded as guarded.

Animals↗
PubMed1998

Relationship between hip external rotation and turnout angle for the five classical ballet positions.

Functional turnout for each of the five classical ballet positions involves lower extremity motion that occurs primarily through hip external rotation. Ballet dancers often attempt to increase turnout angle through excessive motions at the foot or knee that may be associated with the development of musculoskeletal pathology. The purpose of this study was to further the understanding of turnout by identifying the relationship between available hip external rotation an functional turnout for the five classical ballet positions. Subjects were 20 female ballet dancers between the ages of 11 and 14. The investigators measured hip external rotation as the sum of passive external rotation available at both hips of each subject. Functional turnout angle was measured for each subject as the subject stood in each of the five classical ballet positions. A repeated measures analysis of variance and Tukey Honestly Significant Difference test indicated that hip external rotation was significantly less than functional turnout for the five classical ballet positions. No significant differences in functional turnout angle were present among the five ballet functional turnout angle for each of the five ballet positions. Hip external rotation should not be used to predict functional turnout for the five classical ballet positions. Turnout in first position may be useful as guide for functional turnout for the crossed foot positions: third, fourth, and fifth.

Adolescent↗
PubMed1998

In vitro release of colchicine using poly(phosphazenes): the development of delivery systems for musculoskeletal use.

A colchicine release system utilizing biodegradable poly(phosphazenes) was investigated in vitro for intra-articular administration. Polymer degradation and drug release studies were performed on colchicine-loaded poly(phosphazenes) containing either imidazolyl (I-PPHOS) or ethyl glycinato (EG-PPHOS) side chain substituents over a 21-day period. To study the effects of an implantable colchicine-PPHOS delivery system on local musculoskeletal tissue in vitro, osteoblast-like cells were grown on the matrices. Colchicine release was 20% for I-PPHOS and 60% for EG-PPHOS over the 21-day period. Release appeared to proceed through a combination of diffusional and degradative mechanisms. Environmental scanning electron microscopy (ESEM) studies revealed large pores in the drug-depleted devices in contrast to the control matrices without drug, which may have contributed to the release seen, especially with ethyl glycinato-containing matrices. Cell growth on matrices containing colchicine was significantly (p < 0.05) inhibited in contrast to growth on tissue culture polystyrene (TCPS) and EG-PPHOS matrices without drug. The in vitro cell kinetic data suggest that designs for in vivo studies must take into account possible toxicity of colchicine and the polymer matrix on local tissue. Biodegradable PPHOS systems are promising candidates for use as intra-articular delivery vehicles for drugs with potential for systemic toxicity.

3T3 Cells↗