Biomedical subjects

R Burnham

Publications and source records attributed to R Burnham.

At least 19 recordsLinked to original sources

PubMed2006

Fibrous myopathy as a complication of repeated intramuscular injections for chronic headache.

Two cases of fibrous myopathy associated with repeated, long-term intramuscular injections for treatment of chronic temporomandibular joint pain and chronic headache, respectively, are described. Both patients developed severe, function-limiting contractures in upper and lower extremity muscles used as injection sites. In one of the cases, the contractures were painful. Electrophysiological testing, magnetic resonance imaging and muscle biopsy results were all consistent with myopathy and replacement of skeletal muscle with noncontractile fibrous tissue. These cases are presented to increase awareness of fibrous myopathy and to promote surveillance for this serious potential complication of long-term intramuscular injections in chronic headache and other pain patients.

Adult↗

PubMed2001

Infrared skin temperature measurement cannot be used to detect myofascial tender spots.

OBJECTIVE: To determine the relationship between skin temperature and pressure tolerance in patients with myofascial pain. DESIGN: Blinded, criterion standard. SETTING: Community physiatry clinic. PATIENTS: Sixteen consecutive female patients with myofascial pain or fibromyalgia with shoulder girdle symptoms above the T4 level for at least 3 months. No patient met the exclusion criteria of recent trauma to the area or therapy within 48 hours. INTERVENTIONS: Skin temperature was measured by using a hand-held infrared thermometer over 36 points arranged in a grid on the upper and midtrapezius. Pressure threshold was then assessed at each point by using a pressure threshold meter. A second, blinded examiner then examined each patient to find any myofascial tender spots and noted within which square on the grid they occurred. MAIN OUTCOME MEASURES: The correlation between temperature and pressure threshold and the temperature differences between tender and nontender areas. RESULTS: A nonsignificant correlation of.023 (p =.57) was found between temperature and pressure threshold. The mean temperature of the tender spots was 32.1 degrees C. No significant difference existed between tender spot temperature and temperature of nontender points (32.1 degrees C, p =.653) or contralateral points (32 degrees C, p =.893). CONCLUSIONS: Skin temperature, measured with a hand-held infrared thermometer, cannot be used to diagnose and follow treatment progress of myofascial tender spots, because skin temperature over tender spots does not correlate with pressure sensitivity.

Adult↗

PubMed2000

Effect of concurrent strength and endurance training on skeletal muscle properties and hormone concentrations in humans.

The purpose of this study was to investigate the effect of concurrent strength and endurance training on strength, endurance, endocrine status and muscle fibre properties. A total of 45 male and female subjects were randomly assigned to one of four groups; strength training only (S), endurance training only (E), concurrent strength and endurance training (SE), or a control group (C). Groups S and E trained 3 days a week and the SE group trained 6 days a week for 12 weeks. Tests were made before and after 6 and 12 weeks of training. There was a similar increase in maximal oxygen consumption (VO2max) in both groups E and SE (P < 0.05). Leg press and knee extension one repetition maximum (1 RM) was increased in groups S and SE (P < 0.05) but the gains in knee extension 1 RM were greater for group S compared to all other groups (P < 0.05). Types I and II muscle fibre area increased after 6 and 12 weeks of strength training and after 12 weeks of combined training in type II fibres only (P < 0.05). Groups SE and E had an increase in succinate dehydrogenase activity and group E had a decrease in adenosine triphosphatase after 12 weeks of training (P < 0.05). A significant increase in capillary per fibre ratio was noted after 12 weeks of training in group SE. No changes were observed in testosterone, human growth hormone or sex hormone binding globulin concentrations for any group but there was a greater urinary cortisol concentration in the women of group SE and decrease in the men of group E after 12 weeks of training (P < 0.05). These findings would support the contention that combined strength and endurance training can suppress some of the adaptations to strength training and augment some aspects of capillarization in skeletal muscle.

Adult↗

PubMed2000

Quadriceps muscle deoxygenation during functional electrical stimulation in adults with spinal cord injury.

STUDY DESIGN: Cross-sectional study comparing healthy subjects with age and gender matched subjects with spinal cord injury (SCI, injury levels from C5 to T12). OBJECTIVES: To compare the acute cardiorespiratory responses and muscle oxygenation trends during functional electrical stimulation (FES) cycle exercise and recovery in the SCI and healthy subjects exercising on a mechanical cycle ergometer. SETTING: Seven volunteers in each group participated in one exercise test at the Rick Hansen Center, University of Alberta, Edmonton, Canada. METHODS: Both groups completed a stagewise incremental test to voluntary fatigue followed by 2 min each of active and passive recovery. Cardiorespiratory responses were continuously monitored using an automated metabolic cart and a wireless heart rate monitor. Tissue absorbency, an index of muscle oxygenation, was monitored non-invasively from the vastus lateralis using near infrared spectroscopy. RESULTS: The healthy subjects showed significant (P<0.05) increases in the oxygen uptake (VO2), heart rate (HR) and ventilation rate (VE) from rest to maximal exercise. The SCI subjects showed a twofold increase in VO2 (P>0.05), a threefold increase in VE (P<0.05) and a 5 beats/min increase in HR (P>0.05) from the resting value. The SCI subjects demonstrated a lesser degree (P<0.05) of muscle deoxygenation than the healthy subjects during the transition from rest to exercise. Regression analysis indicated that the rate of decline in muscle deoxygenation with respect to the VO2 was significantly (P<0.05) faster in the SCI subjects compared to healthy subjects. CONCLUSIONS: FES exercise in SCI subjects elicits: (a) modest increases in the cardiorespiratory responses when compared to resting levels; (b) lower degree of muscle deoxygenation during maximal exercise, and (c) faster changes in muscle deoxygenation with respect to the VO2 during exercise when compared to healthy subjects.

Adult↗

PubMed1999

Functional electrical stimulation exercise increases GLUT-1 and GLUT-4 in paralyzed skeletal muscle.

The study purpose was to determine the effect of functional electrical stimulation (FES)-leg cycle ergometer training (30 minutes on 3 d/wk for 8 weeks) on the GLUT-1 and GLUT-4 content of paralyzed skeletal muscle. Biopsy samples of vastus lateralis muscle were obtained pre- and post-training from five individuals with motor-complete spinal cord injury ([SCI] four men and one woman aged 31 to 50 years, 3 to 25 years postinjury involving C5-T8). Western blot analysis indicated that GLUT-1 increased by 52% and GLUT-4 increased by 72% with training (P < .05). This coincided with an increase in the muscle oxidative capacity as indicated by a 56% increase in citrate synthase (CS) activity (P < .05) and an improvement in the insulin sensitivity index as determined from oral glucose tolerance tests (P < .05). It is concluded that FES endurance training is effective to increase glucose transporter protein levels in paralyzed skeletal muscle of individuals with SCI.

Adult↗

PubMed1999

Histochemical changes in muscle of individuals with spinal cord injury following functional electrical stimulated exercise training.

STUDY DESIGN: Longitudinal training. OBJECTIVES: To determine the effects of functional electrical stimulated (FES) leg cycle ergometer training on muscle histochemical characteristics in individuals with motor-complete spinal cord injury (SCI). SETTING: University of Alberta, Edmonton, Alberta, Canada. METHODS: Six individuals with motor-complete SCI (age 31-50 years; 3-25 years post-injury) trained using FES leg cycle ergometry for 30 min, 3 days per week for 8 weeks. Biopsies of the vastus lateralis muscle were obtained pre- and post-training and analyzed for fibre composition, fibre size and capillarization. RESULTS: The majority of muscle fibres were classified as type 2 pre- and post-training. Average fibre area increased 23% (P<0.05) and capillary number increased 39% (P<0.05) with training. As a result of these proportional increases, capillarization expressed relative to fibre area was unchanged with training. CONCLUSIONS: FES leg cycle ergometer training results in proportional increases in fibre area and capillary number in individuals with SCI.

Adult↗

PubMed1998

The effectiveness of topical diclofenac for lateral epicondylitis.

INTRODUCTION: Gastrointestinal upset and local pain commonly limit the use of oral nonsteroidal anti-inflammatory drugs and corticosteroid injection as treatments for lateral epicondylitis. Transdermal administration of an anti-inflammatory drug could avoid these adverse effects. PURPOSE: To determine the effectiveness of topical diclofenac as a treatment of lateral epicondylitis. METHODS: A convenience sample of 14 subjects meeting clinical criteria of chronic lateral epicondylitis participated in this randomized, double blind, crossover study. Each subject applied a pluronic lecithin liposomal organo-gel (PLO) over the affected lateral elbow three times daily for I week, followed by a 1-week "washout" period of no gel. A second topical PLO gel was then applied similarly for 1 week. Both gels were identical, but only one gel contained 2% diclofenac. Treatment order was randomized, and both the subject and tester were blinded. Pain and isometric wrist extension strength were measured using a visual analog pain scale (VAS) and a mounted manual muscle testing dynamometer, respectively, at the following time periods: just before application of the first gel, the last day of using the first gel, the last day of the washout week, and the last day of using the second gel. Analysis was performed using repeated measures analysis of variance. RESULTS: When subjects used diclofenac PLO, pain was significantly less than that during the pretreatment, washout, and placebo PLO periods (mean VAS: diclofenac PLO, 2.1; pretreatment, 3.5; washout, 3.4; placebo PLO, 3.6). Average wrist extension strength was significantly greater when subjects used diclofenac PLO (8.4 kg) than it was before treatment (5.9 kg). One subject developed a local rash while using diclofenac PLO. CONCLUSION: Topical 2% diclofenac in PLO appears to provide effective short-term reduction in elbow pain and wrist extensor weakness associated with chronic lateral epicondylitis.

Adult↗

PubMed1998

The effect of a needle biopsy of the vastus lateralis on isokinetic muscular performance.

OBJECTIVE: To determine the acute effects of a needle muscle biopsy of the vastus lateralis on knee extension and flexion strength and endurance. DESIGN: Pretest-posttest design. Testing order of right or left leg was randomly determined. SETTING: Research Laboratory, University of Alberta, Edmonton Alberta, Canada. PARTICIPANTS: The subjects were 8 female and 11 male volunteers who were recreationally active. The mean age, height, and weight were 23 +/- 5 years, 174.6 +/- 9.2 cm, and 73.5 +/- 7.3 kg, respectively. INTERVENTION: Isokinetic testing for knee extension and flexion was performed on both legs before and after a biopsy of the right vastus lateralis muscle. MAIN OUTCOME MEASURES: Knee extension and flexion peak torque measured at an angular velocity of 1.05 rad.s-1. Mean torque during 25 consecutive maximal contractions at 3.14 rad.s-1 for knee extension and flexion exercise. RESULTS: There was a significant decrease in right knee extension peak torque after the biopsy of the vastus lateralis muscle. No other differences were noted. CONCLUSIONS: These findings demonstrated an acute inhibition of knee extension peak torque but not endurance because of a muscle biopsy of the involved musculature.

Adult↗

PubMed1997

Skeletal muscle fibre type transformation following spinal cord injury.

Following spinal cord injury (SCI), upper motor neuron paralysed muscles lose the normal type I (slow) and II (fast) fibre mosaic pattern and become predominantly composed of type II (fast glycolytic) fibres). The majority of the research demonstrating this fibre type shift was based on pH sensitive myofibrillar ATPase staining techniques on muscle from longstanding paraplegics and quadriplegics. The purpose of this study was to describe muscle fibre type changes over a wide time spectrum post SCI using immunofluorescent techniques which may be more sensitive to change. A total of 19 vastus lateralis muscle biopsy specimens were obtained from 12 SCI subjects representing time points of 0.5-219 months post SCI. Fast and slow myosin heavy chain isoform distribution was determined on single muscle fibres for each of the biopsy specimens. Early post SCI (< 1 month) myosin heavy chain (MCH) isoform composition remained relatively stable. A transitional period was seen between 1 and 20 months post SCI wherein there was a progressive drop in the proportion of slow MHC isoform fibres and a rise in the proportion that co-expressed both the fast and slow MHC isoform. By approximately 70 months post SCI a new steady state had been reached characterized by almost exclusively fast MHC isoform expression. This research has demonstrated that post SCI muscle type II transformation occurs in stages and commences earlier than previously appreciated. Interventions aimed at preventing or minimizing the transformation would need to be instituted within weeks post SCI.

Adenosine Triphosphatases↗

PubMed1997

Unusual causes of stiffness in two hockey players.

PURPOSE: To describe two cases of competitive hockey players whose performance was impaired by generalized painless muscle stiffness. They were each found to have a separate type of myotonia. CASE SUMMARY: The first hockey player experienced stiffness only when initiating activity after a period of inactivity. He had a family history of muscle stiffness, grip myotonia clinically, and electrophysiologic findings of myotonic discharges. He had myotonia congenita. The stiffness in the second case was episodic and occurred during bouts of intense physical activity. The legs, arms, and neck were affected. Myotonia fluctuans was the probable diagnosis. Both cases responded well to Mexiletine. DISCUSSION: The etiology, classification, and clinical presentation of myotonia are discussed. RELEVANCE: Because of the musculoskeletal nature of our practice, sport medicine clinicians should be aware of myotonic disorders so they can be recognized and appropriately treated.

Adolescent↗

PubMed1997

Effects of 10-ppm hydrogen sulfide inhalation in exercising men and women. Cardiovascular, metabolic, and biochemical responses.

This study examined the acute effects of 10-ppm hydrogen sulfide (H2S) inhalation, a concentration equal to its occupational exposure limit, on the cardiovascular, metabolic, and biochemical responses in healthy volunteers. Fifteen men and 13 women completed two 30-minute exercise sessions at 50% of their maximal oxygen uptake, during which they inhaled medical air or 10 ppm H2S in a blind manner. Arterial and finger-prick blood samples were obtained before and during the final minute of exercise. Muscle biopsies were withdrawn from the right vastus lateralis immediately after exercise. Cardiorespiratory measurements were monitored using an automated metabolic cart interfaced with an electrocardiogram and blood pressure apparatus. A significant decrease in oxygen uptake (VO2), with a concomitant increase in blood lactate, was observed in men and women as a result of H2S exposure. No significant changes were observed in arterial blood parameters and the cardiovascular responses under these conditions. Muscle lactate, as well as the activities of lactate dehydrogenase, citrate synthase, and cytochrome oxidase, were not significantly altered by H2S exposure. However, there was a tendency for muscle lactate to increase and citrate synthase activity to decrease in both genders in the presence of H2S. It appeared that 10-ppm H2S inhalation reduced VO2 during exercise, most likely by inhibiting the aerobic capacity of the exercising muscle. These findings question the scientific validity of the current occupational exposure limit for H2S.

Administration, Inhalation↗

PubMed1996

Hormonal responses to graded-resistance, FES-assisted strength training in spinal cord-injured.

Functional electrical stimulation (FES) assisted resistance training has been effective in increasing muscular strength and endurance in spinal cord injured men and women in preparation for FES-assisted cycle programs and for FES-assisted standing and walking. Increases in blood pressure and a concomitant bradycardia suggestive of autonomic dysreflexia have been reported during FES-assisted resistance training. Self-induced autonomic dysreflexia in athletes who use wheelchairs suppressed the normal exercise induced serum testosterone increase. We, therefore, examined the changes in hematocrit and circulating levels of testosterone, sex hormone binding globulin (SHBG), cortisol, prolactin, norepinephrine and epinephrine during FES assisted resistance exercise in five high spinal cord injured men (SCI) and comparable maximal exercise in five able bodied controls (AB). Mean serum testosterone levels significantly increased with FES-assisted resistance training in SCI and maximal resistance exercise in AB with no significant change in hematocrit or SHBG. Prolactin, cortisol and epinephrine levels were unchanged while norepinephrine levels were significantly increased in SCI and AB. These findings suggest that there is no concern over inadequate physiological androgen response to an exercise stimulus in SCI. The data do not support the previous findings that elevated levels of norepinephrine in autonomic dysreflexia suppress testosterone response to exercise.

Adult↗

PubMed1996

Effects of 5 ppm hydrogen sulfide inhalation on biochemical properties of skeletal muscle in exercising men and women.

This study compared the acute effects of 5 ppm hydrogen sulfide (H2S) inhalation (50 % of its occupational exposure limit) on the biochemical properties of skeletal muscle in exercising men and women. Twenty-five healthy volunteers, 13 men and 12 women, completed two 30-minute submaximal tests at 50% of their predetermined maximal aerobic power (VO2max) while breathing 0 ppm (control) or 5 ppm H2S from a specially designed flow system in a single-blind manner. Immediately after exercise, biopsies were obtained from the vastus lateralis muscle under local anaesthesia. They were subsequently analyzed for concentrations of the following markers of anaerobic and aerobic metabolism: lactate (La), lactate dehydrogenase (LDH), citrate synthase (CS), and cytochrome oxidase (CytOx). Repeated measures analysis of variance indicated that in men, the CS concentration decreased significantly (p = 0.006) as a result of H2S exposure. There was also a tendency for their La and LDH concentrations to increase and CytOx concentration to decrease in the presence of H2S, but these changes were not significant (p > 0.05). In women no significant changes were observed in any of these biochemical properties. These results suggest that (1) exposure to H2S at 50% of its OEL might inhibit aerobic metabolism during exercise in healthy men, thereby increasing their dependency on anaerobic metabolism; and (2) there could be a significant gender difference in the acute response to sub-OEL exposures of H2S.

Administration, Inhalation↗

PubMed1996

Effects of 10-ppm hydrogen sulfide inhalation on pulmonary function in healthy men and women.

This study examined the acute effects of oral inhalation of 10-ppm hydrogen sulfide (H2S) inhalation (a concentration equal to its occupational exposure limit) on the pulmonary function in healthy men and women. Nine men and ten women consented to inhale medical air or 10 ppm H2S for 15 minutes each during cycle exercise at 50% of their maximal aerobic power. Routine pulmonary function tests were administered at rest and immediately after the two exposure conditions. The results indicated no significant changes in any of the variables derived from the flow volume loop, maximum ventilation volume, and diffusion capacity of the lung for carbon monoxide in both genders. None of the subjects experienced any signs and symptoms as a result of H2S exposure. It was concluded that oral inhalation of 10 ppm H2S at an elevated metabolic and ventilation rate does not significantly alter pulmonary function in healthy men and women.

Adult↗

PubMed1995

Efficacy of rowing, backward wheeling and isolated scapular retractor exercise as remedial strength activities for wheelchair users: application of electromyography.

Shoulder dysfunction due to regular wheelchair use is a common problem among people with spinal cord injuries. As a remedial measure, strengthening of the scapular retractor muscles has been suggested. Electromyographical analysis was utilized to examine scapular retraction muscle use during rowing, backward wheeling and a standardized scapular retraction exercise in seven people with spinal cord injuries and seven able bodied subjects. In addition, a pilot study using indwelling electrodes was completed to validate the use and placement of surface electrodes. Both rowing and the standardized scapular retraction exercise recruited higher levels of retractor involvement than backward wheeling. We suggest that rowing, because of its value as a cardiovascular exercise and high level of retractor recruitment, is an appropriate and effective means of remediating scapular retractor weakness.

Adult↗

PubMed1994

Testosterone, cortisol and catecholamine responses to exercise stress and autonomic dysreflexia in elite quadriplegic athletes.

Episodes of short high intensity exercise are associated with an increase in circulating total testosterone (T) in men. Mechanisms may include hemoconcentration, decreased metabolic clearance and/or increased synthesis. Beta-blockade abolishes the T response suggesting a direct beta-adrenergic effect on the testes. Some spinal cord injured (SCI) athletes deliberately induce autonomic dysreflexia (boosting) to enhance performance. Associated with this practice are elevated catecholamine (CA) levels and exaggerated responses to serum catecholamine levels. Since basal T levels are reported to be normal in the SCI male, the T response to acute high intensity exercise might be expected to be exaggerated by boosting and associated elevated CA levels. The acute exercise T response has not been examined in SCI men to date. To determine whether the increased CA values associated with boosting enhanced the exercise-induced T elevation we measured circulating levels of T, cortisol (C), norepinephrine (NE) and epinephrine (E) before and after maximal exertion and a simulated 7.5 km race with and without boosting in eight elite quadriplegic athletes. Maximal incremental exercise and a simulated 7.5 km race resulted in a rise in T similar to able bodied men under normal exercise conditions. Under boosted conditions the rise in T was eliminated while NE levels were significantly elevated above unboosted levels. The data may suggest an inhibitory role for CA on T production or release under conditions of extreme stress. Other possible mechanisms include C induced suppression, impaired gonadotropin stimulation of the Leydig cell and CA mediated alterations in gonadal blood supply.

Aerobiosis↗

PubMed1994

Comparative physiological responses of exercising men and women to 5 ppm hydrogen sulfide exposure.

A study compared the effects of inhalation of 5 ppm hydrogen sulfide (50% of its occupational exposure limit) on the physiological and hematological responses of healthy men and women during exercise. Subjects were 13 men (mean +/- SD for age, height, and weight = 24.7 +/- 4.6 yr, 173 +/- 6.6 cm, 73.1 +/- 8.1 kg, respectively) and 12 women (mean +/- SD for age, height, and weight = 22.0 +/- 2.1 yr, 165 +/- 8.2 cm, 63.4 +/- 8.6 kg, respectively). Subjects completed two 30-minute exercise tests on a cycle ergometer at 50% of their predetermined maximal aerobic power while breathing medical air or 5 ppm H2S from a specially designed flow system. The results indicated that there were no significant differences between the two exposures for the metabolic (oxygen uptake, carbon dioxide production, respiratory exchange ratio), cardiovascular (heart rate, blood pressure, rate pressure product), arterial blood (oxygen and carbon dioxide tensions, pH), and perceptual (rating of perceived exertion) responses in either sex. None of the subjects reported any adverse health effects subsequent to the H2S exposure. These results suggest that healthy men and women can safely perform moderate intensity work in environments contaminated with 5 ppm H2S.

Adult↗

PubMed1994

Acute median nerve dysfunction from wheelchair propulsion: the development of a model and study of the effect of hand protection.

Carpal tunnel syndrome is prevalent among individuals who are wheelchair dependent. Maximal electrophysiologic median nerve dysfunction has been isolated to the proximal part of the carpal tunnel--the site of hand-wheel interface during wheeling. The objective of this study was to determine if measurable median nerve dysfunction (conduction slowing or block) results from a single session of vigorous wheeling and, if so, if protection for the hand with a glove (padded over the region of the carpal tunnel) could minimize the dysfunction. Thirty-five subjects (16 wheelchair dependent; 19 able-bodied) propelled a roller-mounted wheelchair at maximal rate of 2,000 hand strikes. A protective glove was worn on 1 hand only. Immediately before and after the wheeling, hand surface temperatures and bilateral median motor and sensory conductions were performed, and across-carpal tunnel conduction velocity and conduction block were calculated. Another group of 11 able-bodied subjects underwent similar electrodiagnostic testing before and after one half hour of vigorous stationary cycling (no hand trauma). Results were analyzed using a three-way analysis of covariance for repeated measures and demonstrated that (1) significant increases (5.2% to 8.5%) in across carpal tunnel conduction block occurred as a result of wheelchair propulsion but not cycling; (2) the wheeling-induced conduction block was not altered by using a protective glove. This study has demonstrated a model for measuring acute median nerve dysfunction resultant from wheeling but raises doubts regarding the protective effect of glove use on median nerve function.

Adolescent↗