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Biomedical subjects

A M Hunter

Publications and source records attributed to A M Hunter.

At least 19 recordsLinked to original sources
PubMed2006

Effect of lower limb massage on electromyography and force production of the knee extensors.

OBJECTIVE: To evaluate the effect of massage on force production and neuromuscular recruitment. METHODS: Ten healthy male subjects performed isokinetic concentric contractions on the knee extensors at speeds of 60, 120, 180, and 240 degrees /s. These contractions were performed before and after a 30 minute intervention of either rest in the supine position or lower limb massage. Electromyography (EMG) and force data were captured during the contractions. RESULTS: The change in isokinetic mean force due to the intervention showed a significant decrease (p<0.05) at 60 degrees /s and a trend for a decrease (p = 0.08) at 120 degrees /s as a result of massage compared with passive rest. However, there were no corresponding differences in any of the EMG data. A reduction in force production was shown at 60 degrees /s with no corresponding alteration in neuromuscular activity. CONCLUSIONS: The results suggests that motor unit recruitment and muscle fibre conduction velocity are not responsible for the observed reductions in force. Although experimental confirmation is necessary, a possible explanation is that massage induced force loss by influencing "muscle architecture". However, it is possible that the differences were only found at 60 degrees /s because it was the first contraction after massage. Therefore muscle tension and architecture after massage and the duration of any massage effect need to be examined.

Adult↗
PubMed2003

EMG amplitude in maximal and submaximal exercise is dependent on signal capture rate.

This study analysed the effect of different electromyographic (EMG) capture rates during maximal voluntary contraction, submaximal and maximal dynamic cycling activity on EMG amplitude and signal characteristics. Ten healthy subjects participated in this study. Peak power output (PPO) and maximal isometric force output (MVC) were measured, followed by a progressive cycle ride on a cycle ergometer. Electromyographic (EMG) data were simultaneously captured during the MVC and cycling activities at frequencies of 32, 64, 128, 256, 512, 1024 and 1984 Hz. Significant differences in amplitude were found (p < 0.01) between MVC, submaximal (SUB) and maximal cycling activities (PWATT) for all capture rates. Asymptote values for IEMG amplitude occurred at EMG capture rates of 1604 +/- 235.6 Hz during MVC, 503.1 +/- 236.2 Hz during PWATT and 326.2 +/- 105.4 Hz during SUB cycling activity and were significantly different (p < 0.01). No significant differences were found for force/EMG ratios between PWATT and MVC at 1984 Hz capture rates (3.8 +/- 1.7 N/V vs 2.5 +/- 0.9 N/V) while significant differences occurred at 32 Hz capture rate (6.2 +/- 3.8 vs 16.0 +/- 8.0; p < 0.01). Low correlations were found between EMG activity captured at 1984 Hz during PWATT and lean thigh volume (r = 0.36) and MVC (r = 0.32). Asymptote values found on this study suggest that data captured below 326 Hz for SUB, 503 Hz for PWATT and 1604 Hz for MVC are not reliable. Therefore apparatus capturing EMG data at low frequencies from these values cannot be used for quantitative data analyses.

Adult↗
PubMed2003

Effects of supramaximal exercise on the electromyographic signal.

AIM: To determine the neuromuscular recruitment characteristics during supramaximal exercise. METHODS: Ten healthy subjects completed the Wingate anaerobic test (WAT) cycling protocol. Electromyographic (EMG) data and rate of fatigue were recorded throughout the cycling. RESULTS: The mean (SD) rate of fatigue (decrease in power output) was 44.5 (8.6)%. No significant change was found in EMG amplitude. A significant decrease (p<0.01) in mean power frequency spectrum was found over the 30 second period. CONCLUSIONS: During WAT, mean power frequency spectrum was attenuated with no decline in EMG amplitude, which may be caused by an accumulation of metabolites in the periphery. However, it is also possible that the feedback loop from intramuscular metabolism to the central nervous system is unable, within the 30 second period of the WAT, to affect neural recruitment strategy.

Adult↗
PubMed2002

The effects of heat stress on neuromuscular activity during endurance exercise.

This study analysed the effect of hot (35 degrees C) and cold (15 degrees C) environments on electromyographic (EMG) signal characteristics, skin and rectal temperatures and heart rate during progressive endurance exercise. Eight healthy subjects performed three successive 15-min rides at 30%, 50% and 70% of their peak sustained power output and then cycled at increasing (15 W/min) work rates to exhaustion in both 35 degrees C and 15 degrees C environments. Skin and rectal temperatures, heart rate and EMG data were measured during the trials. The skin temperatures were higher and the subjects felt more uncomfortable in the hot conditions (Bedford scale) ( P<0.01). Rectal temperature was slightly, but not significantly, higher under hot conditions. Heart rate was significantly higher in the hot group (between condition P<0.05). Peak power output (267.4+/-67.7 W vs. 250.1+/-61.5 W) and time-to-exhaustion (55.7+/-16.7 min vs. 54.5+/-17.1 min) (COLD vs. HOT) were not different between conditions. There were no differences in integrated EMG (IEMG) or mean power frequency spectrum between conditions. Rating of perceived exertion increased similarly in both conditions over time. Although the hot conditions increased heart rate and skin temperature, there were no differences in muscle recruitment or maximal performance, which suggests that the thermal stress of 35 degrees C, in combination with exercise, did not impair maximal performance in this study.

Adult↗
PubMed2000

Effects of microtubule-associated protein (MAP) expression on methylmercury-induced microtubule disassembly.

The sensitivity of microtubules (MTs) to methylmercury- (MeHg) induced disassembly was compared in undifferentiated, MAP1A- and MAP2C-transfected, and neuronally differentiated P19 Embyronal Carcinoma (EC) cells. The extent of MT disassembly was examined qualitatively by immunofluorescence microscopy and Western blotting and quantitatively by dot blotting of polymer and soluble proteins extracts. Immunofluorescence microscopy showed that MeHg disassembled MTs in a time- and dose-dependent manner and that MTs in both MAP2C-transfected and neuronally differentiated cells, but not those in MAP1A-transfected cells, were significantly more resistant to MeHg-induced MT depolymerization than those in undifferentiated cells. These results suggest that MAP2C has a greater ability to stabilize MTs against MeHg-induced disassembly than MAP1A. Surprisingly, however, when the extent of MT disassembly was assessed by Western blotting and by quantitative dot blotting, no change was observed in the amounts of tubulin, MAP2, or MAP1A, in the polymer and soluble fractions in MeHg-treated samples, compared to the control cells that were not treated. These data show that, although MeHg treatment resulted in the disassembly of MTs, they were not depolymerized as detergent-soluble subunits, but rather appeared to form insoluble tubulin-MAP oligomers or aggregates.

Animals↗
PubMed1996

Nutrition management of patients with neoplastic disease of the head and neck treated with radiation therapy.

Neoplastic lesions of the head and neck are primarily squamous cell carcinomas of the aerodigestive tract mucosa. Approximately 43,000 new cases of head and neck cancer (8.5% of all malignancies) are diagnosed in the United States each year. Tumors, with a male predominance at age 50 to 60 years, generally occur on the surface of the mucosal lining of the oral cavity, oropharynx, nasopharynx, larynx, maxillary sinus, salivary glands, and the thyroid gland. Tobacco, alcohol, and the combination of tobacco and alcohol are the principle causative agents of head and neck neoplasms. The use of these carcinogenic agents often has a negative impact on lifestyle, and it is not unusual for significant nutritional deficiencies to exist in this population before diagnosis of head and neck cancer. Definitive and adjuvant cancer treatment modalities are rigorous, and sequelae associated with the therapy often further impair nutritional status and increase morbidity. Auspicious nutrition assessment and management before the initiation of therapy can have a significant impact on the course of treatment and the patient's quality of life.

Female↗
PubMed1989

Yellow nail syndrome associated with empyema.

The yellow nail syndrome is a rare condition consisting of slow-growing dystrophic nails and oedema, usually affecting the ankles, and probably due to defective lymphatic drainage. Its association with mild chronic pulmonary disease has been recognized. We describe a case initially complicated by a recurrent pleural effusion but, more importantly, by the development of bronchiectasis and thoracic empyema.

Empyema↗
PubMed1984

Pulmonary infection with mycobacterium xenopi: review of treatment and response.

Forty seven patients (82% male) with pulmonary infection caused by Mycobacterium xenopi have been reviewed. Pre-existing lung disease was present in 35 (75%). In 21 patients the disease was characterised by a subacute illness developing over a period of two to four months, while in another 20 patients there was a longer history of chronic respiratory problems often associated with slowly progressive changes evident from chest radiographs. Response to treatment was poor and unpredictable, and was not related to the results of in vitro sensitivity tests, pre-existing lung disease, or mode of onset of symptoms. Eleven patients (23%) were cured with chemotherapy. The best drug regimen appeared to be rifampicin and isoniazid combined with either streptomycin or ethambutol. Another 12 (26%) showed favourable responses to drug treatment initially, but eventually relapsed. Four patients had progressive disease while receiving prolonged courses of chemotherapy. Resection was performed in five patients with resultant cure in four. Since the prognosis with drug treatment alone is so unpredictable it is suggested that resection might be part of first line treatment, and that it should usually be performed if patients fail to respond to initial chemotherapy or if they relapse.

Adult↗
PubMed1983

Pulmonary infection with Mycobacterium kansasii in Wales, 1970-9: review of treatment and response.

Thirty-five patients (88% male) with pulmonary infection caused by Mycobacterium kansasii have been reviewed. Sixty-six per cent had pre-existing lung disease, chronic bronchitis and emphysema accounting for half of the disorders. Unilateral lesions were present in 69% of patients whose chest radiographs were reviewed and 90% had cavitating disease. The development of unilateral or bilateral disease appeared to be independent of any delay in starting treatment. Five patients died while receiving treatment, but none of these deaths was due to M kansasii infection. The remaining 30 patients were successfully treated with drug regimens, all of which included rifampicin and 86% of which included ethambutol. There was 100% sputum conversion, with no relapses after a mean follow-up period of five-and-a-half years. Rifampicin and ethambutol given for a mean period of 15 months appeared to be a non-toxic, effective combination.

Adult↗
PubMed1983

Retrospective survey of the management of miliary tuberculosis in South and West Wales, 1976-8.

In a survey of 1000 patients with tuberculosis 28 were found to have miliary disease. Half of these patients were over 60 years old. Anorexia and weight loss were present in 19 (70%) and pyrexia in 17 (63%). A factor predisposing to tuberculosis or a history of recent contact was found in 12 (43%), and 21 (75%) had positive cultures. Seventeen (61%) had classical miliary shadowing while four (14%) had cryptic miliary tuberculosis with no radiological evidence of tuberculosis. The remaining seven patients (25%) had radiological changes consistent with pulmonary tuberculosis, but no miliary shadows. Of those who completed chemotherapy, only five (42%) received 18 months' treatment. Nine patients (32%) died from their miliary tuberculosis. Failure to consider the diagnosis, leading to a delay in starting chemotherapy, appeared to be a major problem.

Adolescent↗
PubMed1982

Management of extra-pulmonary tuberculosis (excluding miliary and meningeal) in south and west Wales (1976-8).

In a retrospective survey of the management of extrapulmonary tuberculosis lymph node and genitourinary tuberculosis were found more commonly than bone and joint or gynaecological disease. Only 29% of patients received 18 moths' chemotherapy while 31% received nine to 12 months' treatment with rifampicin and isoniazid regimens and 34% had short-course chemotherapy with other regimens. Five patients were not offered any chemotherapy after diagnosis, and in five patients the diagnosis was overlooked because of administrative errors. One patient died from tuberculosis (renal). Poor drug compliance appeared less of a problem than in pulmonary tuberculosis. Only 14% of patients had their disease managed solely by consultants who were not specialists in chest disease. Liaison with a chest consultant did not necessarily ensure chemotherapy for 18 moths.

Adolescent↗
PubMed1982

Survey of pulmonary tuberculosis in south and west Wales (1976-8).

In routine clinical practice 20% of patients with pulmonary tuberculosis were treated with the regimen recommended by the British Thoracic Association after the British trial of short-course chemotherapy. Despite the use of several regimens that could be considered inadequate, no patients from the survey within south and west Wales appears to have relapsed yet. Deaths from pulmonary tuberculosis continue at the same rate as 10 years ago. Patient default remains a difficult problem even with modern, less toxic, short-course regimens.

Adolescent↗
PubMed1981

The changing pattern of laryngeal tuberculosis.

Laryngeal tuberculosis is now an uncommon disease in the United Kingdom. A series of ten cases is reported. In contrast to the pre-chemotherapy era, when the disease was associated with advanced cavitated pulmonary tuberculosis and was highly infectious, it now presents in a manner similar to laryngeal carcinoma except that painful dysphagia is a prominent symptom. All such patients should have a chest X-ray carried out as part of their initial investigation. Sputum is almost always positive for tubercle bacilli on direct films. Direct laryngoscopy and biopsy are necessary if a carcinoma is suspected. The change of pattern of the disease may be due to the fact that the larynx now usually becomes involved by haematogenous spread rather than by direct spread along the airways. Laryngeal tuberculosis is now no more infectious than pulmonary tuberculosis, and responds well to antituberculous chemotherapy. Symptoms resolve completely within three weeks if corticosteroids are given in combination.

Aged↗
PubMed1981

Circulating immune complexes and autoantibodies in lung cancer.

The sera of 80 newly diagnosed lung-cancer patients have been examined for immune complexes and autoantibodies. Control subjects consisted of 20 bronchitic patients and 150 normal blood donors. Immune-complex measurements used 4 established and sensitive techniques (Raji cell assay, fluid and solid-phase C1q assays and conglutinin-binding assay) and a 5th newly devised technique based on the binding of polyethylene-glycol-precipitated immune-complex-rich serum fractions to Staphylococcus aureus. Using the Raji cell assay and the S. aureus binding assay to measure immune complexes, both newly diagnosed lung cancer patients and bronchitic patients had significantly higher prevalences of immune complexes than normal controls, but the two groups of patients did not differ significantly in either prevalence or quantity of immune complexes. When techniques which depend solely upon complement fixation (C1q assays and conglutinin binding) were used, only meagre quantities of immune complexes were found, and in at most 15% of newly diagnosed lung-cancer patients. The presence of autoantibodies in newly diagnosed cancer patients and controls appeared to correlate with the increase in the detectable prevalence of immune complexes.

Adolescent↗
PubMed1981

Treatment of pulmonary infections caused by mycobacteria of the Mycobacterium avium-intracellulare complex.

Sixty-four patients with pulmonary infection caused by mycobacteria of the M avium-intracellulare complex have been reviewed. Patients who were asymptomatic on presentation often had a benign course but some developed progressive disease. Symptomatic patients who were not treated usually deteriorated. Various treatment regimens were used. Successful treatment was achieved in the majority of patients using a combination of isoniazid, rifampicin, and either ethambutol or streptomycin given for 24 months. Other forms of treatment given including multiple drug regimens were not as effective.

Adult↗