Why exercise in paraplegia?
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Electric Stimulation↗
Biomedical subjects
M Kjaer
Publications and source records attributed to M Kjaer.
Growth hormone enhances effects of endurance training on oxidative muscle metabolism in elderly women.
The present study investigated whether recombinant human (rh) growth hormone (GH) combined with endurance training would have a larger effect on oxidative capacity, metabolism, and body fat than endurance training alone. Sixteen healthy, elderly women, aged 75 yr, performed closely monitored endurance training on a cycle ergometer over 12 wk. rhGH was given in a randomized, double-blinded, placebo-controlled design in addition to the training program. GH administration resulted in a doubling of serum insulin-like growth factor I levels. With endurance training, peak oxygen uptake increased by approximately 18% in both groups, whereas the marked increase in muscle citrate synthase activity was 50% larger in the GH group compared with the placebo group. In addition, only the GH group revealed an increase in muscle L-3-hydroxyacyl-CoA dehydrogenase activity. Body weight remained unchanged in both groups, but the GH group showed significant changes in body composition with a decrease in fat mass and an increase in lean body mass. Twenty-four-hour indirect calorimetry performed in four subjects showed a marked increase in energy expenditure with increased relative and absolute fat combustion in the two subjects receiving rhGH. In conclusion, rhGH adds to the effects of endurance training on muscle oxidative enzymes and causes a reduction in body fat in elderly women.
3-Hydroxyacyl CoA Dehydrogenases↗
Passive energy absorption by human muscle-tendon unit is unaffected by increase in intramuscular temperature.
The present study measured hamstring intramuscular temperature and muscle-tendon unit viscoelastic properties in healthy young men before and after 10 and 30 min of running with (day S) or without stretch (day NS). On day NS, passive energy absorption and intramuscular temperature were measured before running (Preex), after 10 min of running at 70% of maximum O(2) uptake (Postex10), and after 30 min of running at 75% of maximum O(2) uptake (Postex30). On day S, the protocol was repeated with three stretches (stretches 1-3) added after Postex10. Intramuscular temperature was elevated Postex10 (P < 0.01) and further Postex30 (P < 0.05). On day NS, the total energy absorbed Preex (14.3 +/- 2.3 J), Postex10 (14.5 +/- 3.2 J), and Postex30 (13.5 +/- 2.4 J) was not different. On day S, the total energy absorbed in stretch 3 (10.8 +/- 1.8 J) was lower than that Preex (14.5 +/- 1.7 J, P < 0.01) and Postex10 (13.5 +/- 1.9 J, P < 0.05) but not Postex30 (13.3 +/- 1.8 J). The total energy absorbed Postex30 did not differ from Preex. In conclusion, warm-up and continuous running elevated intramuscular temperature but did not affect the passive energy absorption. Repeated passive stretching reduced the energy absorption immediately; however, the effect did not remain after 30 min of running. These data suggest that passive energy absorption of the human skeletal muscle is insensitive to physiological increases in intramuscular temperature.
Adult↗
Regional blood flow during exercise in humans measured by near-infrared spectroscopy and indocyanine green.
Using near-infrared spectroscopy (NIRS) and the tracer indocyanine green (ICG), we quantified blood flow in calf muscle and around the Achilles tendon during plantar flexion (1-9 W). For comparison, blood flow in calf muscle was determined by dye dilution in combination with magnetic resonance imaging measures of muscle volume, and, for the peritendon region, blood flow was measured by (133)Xe washout. From rest to a peak load of 9 W, NIRS-ICG blood flow in calf muscle increased from 2.4+/-0.2 to 74+/-5 ml x 100 ml tissue(-1) x min(-1), similar to that measured by reverse dye (77+/-6 ml x 100 ml tissue(-1) x min(-1)). Achilles peritendon blood flow measured by NIRS-ICG rose with exercise from 2.2+/-0.5 to 15.1+/-0.2 ml x 100 ml(-1) x min(-1), which was similar to that determined by (133)Xe washout (2.0+/-0.6 to 14.6+/-0.3 ml x 100 ml tissue(-1) x min(-1)). This is the first study using NIRS and ICG to quantify regional tissue blood flow during exercise in humans. Due to its high spatial and temporal resolution, the technique may be useful for determining regional blood flow distribution and regulation during exercise in humans.
Coloring Agents↗
Type I collagen synthesis and degradation in peritendinous tissue after exercise determined by microdialysis in humans.
1. Physical activity is known to increase type I collagen synthesis measured as the concentration of biomarkers in plasma. By the use of microdialysis catheters with a very high molecular mass cut-off value (3000 kDa) we aimed to determine local type I collagen synthesis and degradation in the peritendinous region by measuring interstitial concentrations of a collagen propeptide (PICP; 100 kDa) and a collagen degradation product (ICTP; 9 kDa) as well as an inflammatory mediator (PGE2). 2. Seven trained human runners were studied before and after (2 and 72 h) 3 h of running (36 km). Two microdialysis catheters were placed in the peritendinous space ventral to the Achilles' tendon under ultrasound guidance and perfused with a Ringer-acetate solution containing 3H-labelled human type IV collagen and [15-3H(N)]PGE2 for in vivo recovery determination. Relative recovery was 37-59 % (range of the s.e.m. values) for both radioactively labelled substances. 3. PICP concentration decreased in both interstitial peritendinous tissue and arterial blood immediately after exercise, but rose 3-fold from basal 72 h after exercise in the peritendinous tissue (55 +/- 10 microg l-1, mean +/- s.e.m. (rest) to 165 +/- 40 microg l-1 (72 h), P < 0.05) and by 25 % in circulating blood (160 +/- 10 microg l-1 (rest) to 200 +/- 12 microg l-1 (72 h), P < 0.05). ICTP concentration did not change in blood, but decreased transiently in tendon-related tissue during early recovery after exercise only. PGE2 concentration increased in blood during running, and returned to baseline in the recovery period, whereas interstitial PGE2 concentration was elevated in the early recovery phase. 4. The findings of the present study indicate that acute exercise induces increased formation of type I collagen in peritendinous tissue as determined with microdialysis and using dialysate fibre with a very high molecular mass cut-off. This suggests an adaptation to acute physical loading also in non-bone-related collagen in humans.
Achilles Tendon↗
[From exercise physiology to sports medicine].
Physical activity causes marked circulatory and metabolic adaptations, and results in marked alterations in e.g. skeletal muscle and connective tissue. Strengthening of skeletal- and heart-muscle, an improved oxidative capacity and an increased hormone sensitivity not only lead to an improved overall functional level in elderly and in frail patients, but also contribute to improvement in risk factors for development of inactivity related diseases. Patient groups can achieve pronounced both general and more disease specific improvements through regular physical activity, and better knowledge as regards to how exercise can be used correctly as therapy in rehabilitation, in preventing loss of function and disease development, and in training of the chronically sick is needed. Exercise leads to a large amount of overuse injuries in connective tissue. Through usage of in-vivo techniques it has become possible to study tissue (e.g. tendon) adaptation to physical loading and training more closely. A deeper understanding of the underlying mechanisms behind the development of overuse injuries is crucial for diagnostic and treatment regimens not only in sports medicine, but also in more general terms within disease prevention and treatment.
Aging↗
Effect of adrenaline on glucose kinetics during exercise in adrenalectomised humans.
1. The role of adrenaline in regulating hepatic glucose production and muscle glucose uptake during exercise was examined in six adrenaline-deficient, bilaterally adrenalectomised humans. Six sex- and age-matched healthy individuals served as controls (CON). 2. Adrenalectomised subjects cycled for 45 min at 68 +/- 1 % maximum pulmonary O2 uptake (VO2,max), followed by 15 min at 84 +/- 2 % VO2, max without (-ADR) or with (+ADR) adrenaline infusion, which elevated plasma adrenaline levels (45 min, 4.49 +/- 0.69 nmol l-1; 60 min, 12.41 +/- 1.80 nmol l-1; means +/- s.e.m.). Glucose kinetics were measured using [3-3H]glucose. 3. Euglycaemia was maintained during exercise in CON and -ADR, whilst in +ADR plasma glucose was elevated. The exercise-induced increase in hepatic glucose production was similar in +ADR and -ADR; however, adrenaline infusion augmented the rise in hepatic glucose production early in exercise. Glucose uptake increased during exercise in +ADR and -ADR, but was lower and metabolic clearance rate was reduced in +ADR. 4. During exercise noradrenaline and glucagon concentrations increased, and insulin and cortisol concentrations decreased, but plasma levels were similar between trials. Adrenaline infusion suppressed growth hormone and elevated plasma free fatty acids, glycerol and lactate. Alanine and beta-hydroxybutyrate levels were similar between trials. 5. The results demonstrate that glucose homeostasis was maintained during exercise in adrenalectomised subjects. Adrenaline does not appear to play a major role in matching hepatic glucose production to the increase in glucose clearance. In contrast, adrenaline infusion results in a mismatch by simultaneously enhancing hepatic glucose production and inhibiting glucose clearance.
Adrenalectomy↗
Postoperative radiotherapy in high-risk postmenopausal breast-cancer patients given adjuvant tamoxifen: Danish Breast Cancer Cooperative Group DBCG 82c randomised trial.
BACKGROUND: Postmastectomy radiotherapy is associated with a lower locoregional recurrence rate and improved disease-free and overall survival when combined with chemotherapy in premenopausal high-risk breast-cancer patients. However, whether the same benefits apply also in postmenopausal women treated with adjuvant tamoxifen for similar high-risk cancer is unclear. In a randomised trial among postmenopausal women who had undergone mastectomy, we compared adjuvant tamoxifen alone with tamoxifen plus postoperative radiotherapy. METHODS: Between 1982 and 1990, postmenopausal women with high-risk breast cancer (stage II or III) were randomly assigned adjuvant tamoxifen (30 mg daily for 1 year) alone (689) or with postoperative radiotherapy to the chest wall and regional lymph nodes (686). Median follow-up was 123 months. The endpoints were first site of recurrence (locoregional recurrence, distant metastases, or both), and disease-free and overall survival. FINDINGS: Locoregional recurrence occurred in 52 (8%) of the radiotherapy plus tamoxifen group and 242 (35%) of the tamoxifen only group (p<0.001). In total there were 321 (47%) and 411 (60%) recurrences, respectively. Disease-free survival was 36% in the radiotherapy plus tamoxifen group and 24% in the tamoxifen alone group (p<0.001). Overall survival was also higher in the radiotherapy group (385 vs 434 deaths; survival 45 vs 36% at 10 years, p=0.03). INTERPRETATION: Postoperative radiotherapy decreased the risk of locoregional recurrence and was associated with improved survival in high-risk postmenopausal breast-cancer patients after mastectomy and limited axillary dissection, with 1 year of adjuvant tamoxifen treatment. Improved survival in high-risk breast cancer can best be achieved by a strategy of both locoregional and systemic tumour control.
Antineoplastic Agents, Hormonal↗
[Bone metabolism and physical training].
Based on a review of the literature, the effect of physical training on bone mineral density (BMD) has been evaluated. There seems to be evidence for increased BMD in children and adults performing weight-bearing physical training, whereas the loss of BMD in the elderly is reduced. No study has documented the necessary level of physical training needed for a positive effect on BMD.
Adolescent↗
Metabolism and inflammatory mediators in the peritendinous space measured by microdialysis during intermittent isometric exercise in humans.
1. The metabolic processes that occur around the tendon during mechanical loading and exercise are undescribed in man. These processes are important for understanding the development of overuse inflammation and injury. 2. A microdialysis technique was used to determine interstitial concentrations of glycerol, glucose, lactate, prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) as well as to calculate tissue substrate balance in the peritendinous region of the human Achilles tendon. Recovery of 48-62 % (range) at rest and 70-77 % during exercise were obtained for glycerol, glucose and PGE2. 3. Six young healthy humans were studied at rest, during 30 min of intermittent static plantar flexion of the ankle at a workload corresponding to individual body weight, and during 60 min of recovery. Microdialysis was performed in both legs with simultaneous determination of blood flow by 133Xe washout in the same area, and blood sampling from the radial artery. 4. With exercise, the net release of lactate as well as of glycerol from the peritendinous space of the Achilles tendon increased 2-fold (P < 0.05). Furthermore a 100 % increase in interstitial concentration of PGE2 and TXB2 was found, but it was only significant for TXB2(P < 0.05). As peritendinous blood flow increased 2- to 3-fold during intermittent static contractions, this indicates also that the output of these substances from the tissue increased during exercise. 5. This study indicates that both lipid and carbohydrate metabolism as well as inflammatory activity is accelerated in the peritendinous region of the human Achilles tendon with dynamic loading.
Achilles Tendon↗
High expression of MHC I in the tibialis anterior muscle of a paraplegic patient.
A long-term paraplegic man presented exclusively (>99%) myosin heavy chain I (MHC I) in the tibialis anterior muscle (TA). This was coupled to a slow speed of contraction, a high resistance to fatigue, and a rapid resynthesis of phosphocreatine after an electrically evoked fatiguing contraction when compared with the TA muscles of 9 other paraplegic individuals. In contrast, the MHC composition of his vastus lateralis, gastrocnemius, and soleus muscles was that expected of a muscle from a spinal cord injured individual. This information may be of clinical importance in terms of the expected morphological and functional adaptations of skeletal muscle to different types of electrical stimulation therapy.
Electromyography↗
Improved physical performance after orthotopic liver transplantation.
Orthotopic liver transplantation (OLT) has become a frequently used treatment for end-stage liver disease and acute liver failure, and liver function is markedly improved after transplantation. However, no studies have investigated the development in physical capacity after OLT. On this basis, the aim of the present study is to study the influence of OLT on physical fitness during the first postoperative year. Twenty-three men with a mean age of 45.1 years (range, 24 to 62 years) and 15 women with a mean age of 44.6 years (range, 21 to 62 years) were included in the study. Preoperative maximal oxygen uptake (VO2max) during graded ergometer bicycling, isokinetic knee extension/flexion moments, and functional performance (i.e., 6-minute walking distance and standardized transfers and squats) was measured. Preoperative fitness and strength was 40% to 50% less than expected in the age-matched general population. Post-OLT, all patients underwent a supervised exercise program for 8 to 24 weeks. Follow-up data showed a significant increase in all tested physical performance parameters after OLT. Six months post-OLT, VO2max had increased 43%; knee strength, 60% to 100%; and functional performance, 22% to 27%. One year postsurgery, general health was improved and perceived as excellent or good in all patients. All patients were independent in activities of daily living, and the level of physical activity increased after OLT. No further improvement in either physical performance parameters or self-assessed parameters was seen beyond 6 months after OLT. In conclusion, these findings indicate that OLT combined with a supervised post-OLT exercise program improves physical fitness, muscle strength, and functional performance in individuals with chronic liver disease.
Activities of Daily Living↗
Salbutamol effect in spinal cord injured individuals undergoing functional electrical stimulation training.
OBJECTIVE: Preliminary study to investigate possible changes in skeletal muscle morphology and function, as well as hormonal and metabolic effects, after treatment with a selective beta2-adrenergic receptor agonist. DESIGN: Double-blind, placebo-controlled trial. PARTICIPANTS: Three individuals with spinal cord injury (SCI). INTERVENTION: Two-week treatment with salbutamol (2mg) or placebo (ascorbic acid, 50mg) twice a day. Program of functional electronic stimulation (FES) cycling for 30 minutes twice a week. MAIN OUTCOME MEASURES: Body weight, three measures of leg circumference (gluteal furrow, one third of subischial height up from tibial-femoral joint space, and minimum circumference above the knee), muscle fiber area, and total work output per session. RESULTS: There were increases in body weight (2.30 +/- .70kg), leg circumferences (gluteal furrow 1.70 +/- .27cm, one third subischial height 1.53 +/- 1.65cm, minimum circumference above the knee .43 +/- .04cm), and muscle (vastus lateralis) cross-sectional area (1,374 +/- 493 to 2,446 +/- 1,177microm2) after salbutamol treatment, whereas quadriceps muscle contractile function was not modified. Total work output during FES cycling sessions was increased more during salbutamol treatment (64%) compared with training alone (27%). Salbutamol treatment was associated with a large decrease in skeletal muscle beta-adrenergic receptor density. CONCLUSION: Although some side effects were noted, these results suggest that a short treatment with the beta2-adrenergic receptor agonist salbutamol during a training program with FES cycling could be beneficial in patients with SCI.
Adrenergic beta-Agonists↗
Tamoxifen in high-risk premenopausal women with primary breast cancer receiving adjuvant chemotherapy. Report from the Danish Breast Cancer co-operative Group DBCG 82B Trial.
Following modified radical mastectomy, pre- and perimenopausal (amenorrhoea for < 5 years) patients with stage II or III breast cancer received CMF (cyclophosphamide 600, methotrexate 40, 5-fluorouracil 600 mg/m2 intravenously (i.v.) every 4 weeks, 9 cycles). The effect on recurrence-free survival (RFS) and overall survival (OS) of the addition of adjuvant tamoxifen (TAM) to adjuvant chemotherapy was examined by randomisation either to no additional treatment (n = 314), or concurrently TAM 30 mg daily for 1 year (n = 320). 40% had positive, 12% negative and 48% unknown receptor status. One year after surgery 21% versus 35% (CMF + TAM versus CMF) were still menstruating (P < 0.01). With a median follow-up of 12.2 years there was no difference in RFS (10-year RFS 34% versus 35%, P = 0.81) or OS (45% versus 46%, P = 0.73). In a Cox proportional hazards model, tumour size, number of metastatic lymph nodes, frequency of metastatic nodes in relation to total number of nodes removed, degree of anaplasia, age, and menostasia within the first year after operation were significant independent prognostic factors for RFS, and the same factors except age for OS. No significant interactions with TAM were seen. Thus, in this group of pre- and perimenopausal high-risk early breast cancer patients with heterogeneous receptor status given CMF i.v., concurrent TAM for 1 year did not improve the outcome. These results do not exclude that receptor positive patients may benefit from adjuvant TAM for longer periods given sequentially to chemotherapy.
Adult↗
Does preoperative night pulse oximetry provide a reliable baseline?
BACKGROUND: Postoperative hypoxaemia may be detected by pulse oximetry monitoring of the arterial haemoglobin saturation (SpO2). The SpO2-values obtained on the preoperative night are presumed to represent baseline values for the patients. The aim of this study was to evaluate the possible difference between nocturnal SpO2-values in the patient's home and in the hospital before operation. METHODS: We included 20 patients, 60 years or older, who underwent continuous monitoring of SpO2 on one night in the patient's home and on the night following hospitalisation before surgery. The alarms were turned off and the values were not accessible to the hospital staff. The SpO2 value was stored every 10 s. We described the general oxygen saturation level using the median of all valid values and we calculated the number of valid SpO2-values at 3 levels: above 90%, between 86 and 90%, and below 86%. RESULTS: The number of valid SpO2-values at home and in the hospital were 2186 and 2330, respectively; the median value was 96% on both occasions. Only 0.36% of the values were below 91% on the two occasions and there were no statistically significant differences between the number of SpO2-values at any of the considered levels. CONCLUSION: Arterial oxygen saturation values measured on the preoperative night in the hospital seem reliable as baseline values for elderly patients.
Aged↗
Granisetron compared with prednisolone plus metopimazine as anti-emetic prophylaxis during multiple cycles of moderately emetogenic chemotherapy.
This randomized, double-blind, double-dummy parallel study compared the anti-emetic efficacy and tolerability of the serotonin antagonist granisetron with prednisolone plus the dopamine D2 antagonist metopimazine during nine cycles of moderately emetogenic chemotherapy. Chemotherapy naive women with stage I or II breast cancer scheduled to intravenous cyclophosphamide, fluorouracil and methotrexate or cyclophosphamide, epirubicin and fluorouracil every 3 weeks were included. Patients received a single intravenous dose of granisetron 3 mg or a 3-day oral treatment with prednisolone 25 mg once a day plus metopimazine 30 mg four times a day. A total of 223 women were enrolled and 218 patients (97.8%) were evaluable for efficacy. Granisetron (n = 109) was superior to prednisolone plus metopimazine (n = 109) in the prophylaxis of acute nausea and vomiting during the first cycle of chemotherapy (P < 0.001) and prednisolone plus metopimazine was superior on days 2-5 (P = 0.002). Overall, granisetron was superior on days 1-5 (P = 0.009). The median number of cycles completed with granisetron was five (95% confidence interval 4-6) compared with two (95% confidence interval 2-2) for prednisolone plus metopimazine (P = 0.0019). Constipation and rash were reported more frequently with granisetron (P < 0.001 and P = 0.043 respectively) and palpitations more frequently with prednisolone plus metopimazine (P = 0.015). In conclusion, the number of cycles completed with granisetron was significantly higher than the number completed with prednisolone plus metopimazine, but the anti-emetic efficacy of both treatments declined during multiple cycles of moderately emetogenic chemotherapy.
Adult↗
Standardized intermittent static exercise increases peritendinous blood flow in human leg.
Alteration in tendinous and peritendinous blood flow during and after exercise is suggested to contribute to the development of Achilles tendon injury and inflammation. In the present study a method for evaluating the influence of standardized workload on peritendinous flow is presented. The radioactive isotope xenon-133 was injected just ventrally to the Achilles tendon 5 cm proximal to the tendon's insertion on the calcaneous. The disappearance of 133Xe was used to determine blood flow during intermittent static exercise of the calf muscle (1.5 s exercise/1.5 s rest) for 30 min at a workload equivalent to individual body weight (1 BW) in six healthy volunteers around both Achilles tendons (n = 12). During intermittent static exercise, blood flow was increased from 1.8 +/- 0.3 ml 100 g tissue-1 min-1 (mean value and SEM) (rest) to 6.1 +/- 1.3 ml 100 g tissue-1 min-1 (exercise) (P < 0.05). The exercise induced an average increase in blood flow (3.4-fold) equivalent to results previously obtained during regular dynamic heel raises (P > 0.05). It is concluded that the method is well suited to study the influence of standardized workload on the physiology and pathophysiology of the tissue around the Achilles tendon in humans.
Achilles Tendon↗
Exercise and organ transplantation.
Life-saving treatment of disease by organ transplantation has become increasingly important. Annually over 35,000 transplantations of vital organs are carried out world-wide and the demand for knowledge regarding exercise in daily life for transplant recipients is growing. The present review describes whole-body and organ reactions to both acute exercise and regular physical training in persons who have undergone heart, lung, liver, kidney, pancreas or bone marrow transplantation. In response to acute exercise, the majority of cardiovascular, hormonal and metabolic changes are maintained after transplantation. However, in heart transplant recipients organ denervation reduces the speed of heart rate increase in response to exercise. Furthermore, lack of sympathetic nerves to transplanted organs impairs the normal insulin and renin responses to exercise in pancreas and kidney transplant recipients, respectively. In contrast, surgical removal of sympathetic liver nerves does not inhibit hepatic glucose production during exercise, and denervation of the lungs does not impair the ability to increase ventilation during physical exertion. Most studies show that physical training results in an improved endurance and strength capacity in almost all groups of transplant recipients, which is of importance for their daily life. With a little precaution, organ transplant recipients can perform exercise and physical training and obtain effects comparable with those achieved in the healthy population of similar age.
Bone Marrow Transplantation↗