Biomedical subjects
D Garlick
Publications and source records attributed to D Garlick.
The effect of jaw clenching on the electromyographic activities of 2 neck and 2 trunk muscles.
AIMS: Symptoms of jaw dysfunction are often associated with neck muscle dysfunction or other musculoskeletal problems. This study attempted to quantify the effect of jaw clenching on the electromyographic (EMG) activity of certain neck, trunk, and jaw muscles. METHODS: The authors recorded EMG muscle activity in the sternocleidomastoid, trapezius, paravertebral, and rectus abdominis muscles in 10 university students at rest and during strong jaw clenching in supine and sitting positions. RESULTS: In both positions, jaw clenching resulted in increases in neck muscle activity ranging from 7.6 to 33 times resting muscle activity; for the trunk muscles, the increases ranged from 1.4 to 3.3 times resting activity. CONCLUSION: These results add further information to the concept of the interrelatedness of jaw, neck, and trunk muscle activity.
Groin pain associated with ultrasound finding of inguinal canal posterior wall deficiency in Australian Rules footballers.
OBJECTIVES: To investigate the prevalence of inguinal canal posterior wall deficiency (sports hernia) in professional Australian Rules footballers using an ultrasound technique and correlate the results with the clinical symptom of groin pain. METHODS: Thirty five professional Australian footballers with and without groin pain were investigated blind with a dynamic high resolution ultrasound technique for presence of posterior wall deficiency. RESULTS: Fourteen players had a history of significant recent groin pain and ten of these were found to have bilateral inguinal canal posterior wall deficiency (p < 0.01). The relative risk for a history of groin pain with bilateral deficiency was 8.0 (95% confidence interval 1.73 to 37.1). Groin pain was also found to be associated with increasing age (p < 0.01) which was an independent risk factor. Surgical, clinical, and ultrasound follow up for players who underwent hernia repair confirmed the validity of ultrasound as a diagnostic tool. CONCLUSIONS: Dynamic ultrasound examination is able to detect inguinal canal posterior wall deficiency in young males with no clinical signs of hernia. This condition is very prevalent in professional Australian Rules footballers, including some who are asymptomatic. There was a correlation between bilateral deficiency and groin pain, although the temporal relationship between the clinical and ultrasound findings is not established by the current study. Ultrasound shows promise as a diagnostic tool in athletes with chronic groin pain who are considered possible candidates for hernia repair.
Acquired cutaneous lymphangiectasis in a dog.
A 3-year-old male mixed-breed dog had swelling of the penile sheath, which developed after the dog was castrated at 1 year of age. Physical examination revealed pitting edema and multiple turgid vesicles on the prepuce and inguinal area. Histologic evaluation of the vesicles revealed thin epidermis elevated by dermal proliferation of dilated lymphatic channels. The diagnosis was acquired cutaneous lymphangiectasia. Clinical signs resolved concurrent with furosemide administration. Preputial swelling without vesicles recurred 1 and 2 years later and partially resolved after furosemide administration.
Transcapillary efflux of gamma globulin in rabbit skeletal muscle.
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Effects of exercise metabolites on adrenergic vasoconstriction in the gracilis muscle of the dog.
Comparable and submaximal responses to sympathetic stimulation and to intra-arterial injections and infusions of norepinephrine were elicited in the isolated dog gracilis muscle, perfused with blood at constantflow. The changes in potassium concentration, osmolality, Po2 and inorganic phosphate concentration were determined during exercise. Blood was perfused to the muscle with the concentrations of each of these parameters varied to include that seen in exercise. Hypoxia (average Po2 5.4 mm Hg) produced a marked vasodilatation, and responses to norepinephrine and sympathetic stimulation were both increased to the same extent, due to the lowered vascular tone. Increases in osmolality (up to 50 mOsmol/kg) caused little antagonism of adrenergic responses, but higher increases caused a significant and equal inhibition of responses to norepinephrine and sympathetic stimulation. Increases in phosphate concentration (plus 41.6 mM) had little effect either on muscle resistance or on adrenergic responses. Increases in potassium concentration (plus10 mM) completely abolished responses to sympathetic stimulation, whereas those to norepinephrine were unaffected. This prejunctional effect may result from inhibition of sympathetic neurotransmission due to depolarization of adrenergic nerve terminals.
Evoked release of tritiated noradrenaline and metabolites in resting and exercising muscle.
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Antagonism of vasoconstrictor responses by exercise in the gracilis muscle of the dog.
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The penetration of inulin, sucrose, mannitol and tritiated water from the interstitial space in muscle into the vascular system.
1. An isolated gastrocnemius muscle from cat was perfused with a modified Ringer fluid containing the extracellular tracers mannitol, sucrose and inulin and in some cases tritiated water (HTO). When equilibration of the tracers between the perfusate and the tissue was obtained, perfusion with tracer-free fluid was started.2. The fractional rate of escape, Phi (t), of the tracers was followed. For all tracers it declined steadily with time. The rate of decline was faster for the smaller extracellular molecules when any combination of two extracellular tracers was studied.3. Arrest of flow for 1-2 min lead to an increase in Phi (t) for the extracellular tracers when flow was resumed. There was little or no effect upon Phi (t) for HTO.4. Doubling the rate of flow had no effect upon Phi (t) for the extracellular tracers, while that of HTO increased.5. We conclude that the cause of the decline in Phi (t) for the extracellular tracers is concentration gradients in the interstitial space. The findings raise problems in methods for studying capillary permeability by means of the fractional rate of escape of tracers from the interstitial space into the vascular system.
Countercurrent exchange of highly diffusible tracers in skeletal muscle: its absence in the lung.
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Preseason hamstring muscle weakness associated with hamstring muscle injury in Australian footballers.
Hamstring muscle strain is the most prevalent injury in Australian Rules Football, accounting for 16% of playing time missed as a result of injury. Thirty-seven professional footballers from an Australian Football League team had preseason measurements of hamstring and quadriceps muscle concentric peak torque at 60, 180, and 300 deg/sec measured on a Cybex 340 dynamometer. Players were studied prospectively throughout the 1995 season. During that time, six players sustained clinically diagnosed hamstring muscle injuries that caused them to miss match-playing time. The injured hamstring muscles were all weaker than in the opposite leg in absolute values and hamstring-to-quadriceps muscle ratios. According to our t-test results, hamstring muscle injury was significantly associated with a low hamstring-to-quadriceps muscle peak torque ratio at 60 deg/sec on the injured side and a low hamstring muscle side-to-side peak torque ratio at 60 deg/sec. Flexibility (as measured by the sit-and-reach test) did not correlate with injury. Discriminant-function analysis using the two significant ratio variables resulted in a canonical correlation with injury of 0.4594 and correctly classified legs into injury groups with 77.4% success. These results indicate that preseason isokinetic testing of professional Australian Rules footballers can identify players at risk of developing hamstring muscle strains.
A comparison of two methods of assessing capillary permeability in isolated perfused muscle based on single injecion technique.
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