Biomedical subjects

A Hartkopp

Publications and source records attributed to A Hartkopp.

10 recordsLinked to original sources

PubMed1999

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↗

PubMed1999

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↗

PubMed1998

Bone fracture during electrical stimulation of the quadriceps in a spinal cord injured subject.

We report a fracture through the lateral femoral condyle of a paraplegic subject caused by electrical stimulation (ES). The subject was a 50-year-old man who 4 years earlier had sustained a complete spinal cord injury (SCI) at level T6. The fracture occurred during ES-induced measurement of maximal isometric torque of the quadriceps with the knee flexed at an angle of 90 degrees. ES was delivered through surface electrodes with biphasic square wave pulses from a constant current stimulator. The torque was calculated to be 93Nm, corresponding to 20.8kg at the ankle. The regional bone mineral density of the entire lower extremities was .83g/cm2, corresponding to 60% of sex- and age-matched able-bodied reference values. Several factors are suspected to have contributed to the fracture: maximal ES in combination with a muscle spasm, severe osteoporosis, increased muscular strength induced by regular ES cycling (twice a week), and testing position with the knee locked in 90 degrees flexion. The risk of fracture as well as various precautions are discussed and should be taken into consideration in future studies.

Biomechanical Phenomena↗

PubMed1998

Suicide in a spinal cord injured population: its relation to functional status.

OBJECTIVE: To determine the relation between functional status and risk of suicide among individuals with spinal cord injury (SCI). DESIGN: A follow-up study of all individuals who survived a traumatic SCI during the period from 1953 through 1990. SETTING: An SCI center in eastern Denmark. SUBJECTS: A total of 888 individuals with SCI, including 236 who died, 23 of whom committed suicide. MAIN OUTCOME MEASURES: Standardized Mortality Ratios (SMRs) of suicides among individuals with SCI. RESULTS: A 100% follow-up was established January 1, 1993. The total suicide rate among individuals with SCI was nearly five times higher than expected in the general population and lower for men than for women. The suicide rate doubled from an early inclusion period (1953-1971) to a later period (1972-1990). An unexpected finding was that the suicide rate in the group of marginally disabled persons was nearly twice as high as the group of functionally complete tetraplegic individuals. CONCLUSION: Given the high frequency of suicide, there is a need for increased awareness by rehabilitation staff and general practitioners regarding depression and psychological adjustment difficulties. Such conditions should be given special attention during rehabilitation and follow-up, especially among women with SCI and the marginally disabled.

Denmark↗

PubMed1997

Muscle strength and soft tissue composition as measured by dual energy x-ray absorptiometry in women aged 18-87 years.

Dual energy x-ray absorptiometry (DEXA) offers the possibility of assessing regional soft tissue composition, i.e. lean mass (LM) and fat mass: LM may be considered a measure of muscle mass. We examined age-related differences in LM, percentage fat (%fat) and muscle strength in 100 healthy non-athletic women aged 18-87 years. Relationships between muscle strength and leg LM in 20 elite female weight lifters and in 18 inactive women with previous hip fractures were also studied. The LM and %fat of the whole body, trunk, arms and legs were derived from a whole body DEXA scan. Isokinetic knee extensor strength (KES) and flexor strength (KFS) at 30 degrees.s-1 were assessed using an isokinetic dynamometer. The women aged 71-87 years had 35% lower KES and KFS than the women aged 18-40 years (P < 0.0001). Differences in LM were less pronounced. The LM of the legs, for instance, was 15% lower in the old than in the young women (P < 0.0001). In a multiple regression analysis with age, body mass, height and leg LM or KES as independent variables and KES or leg LM as the dependent variable, age was the most important predictor of KES (r(partial) = -0.74, P < 0.0001). The same applied to KFS. Body mass, not age, was the most important predictor of leg LM (r(partial) = 0.65, P < 0.0001) and of LM at all other measurement sites. The LM measured at different regions decreased equally with increasing age. The KES:leg LM ratio was negatively correlated with age (r = -0.70, P < 0.0001). The weight lifters had significantly higher KES:leg LM ratios than age-matched controls (+ 12%, P < 0.0001) and vice versa for the women with previous hip fractures (-36%, P < 0.0001). In conclusion, from our study it would seem that in healthy nonathletic women, age is a more important determinant of muscle strength than is LM as measured by DEXA. Muscle strengthening exercises and inactivity seem to have a considerably stronger influence on muscle strength than on LM.

Absorptiometry, Photon↗

PubMed1997

Survival and cause of death after traumatic spinal cord injury. A long-term epidemiological survey from Denmark.

Life expectancy among individuals with spinal cord injuries (SCI) has remained lower than in the normal population, even with optimal medical management. But significant improvement has been achieved, as will be illustrated in this retrospective study of an unselected group of traumatic survivors of SCI, dead or still living. There has been a complete follow-up over 4 decades, information being obtained from available medical records, death certificates, and post mortem records. The survey included a total of 888 individuals (713 men and 175 women) who had survived the injury and primary treatment and were rehabilitated at the centre for Spinal Cord Injured in Hornbaek, Denmark. At the end of the follow-up, 31st December 1992, 236 (197 men and 39 women) had died. The commonest causes of death were lung diseases, particularly pneumonia; suicide; and ischaemic heart disease. Among functionally complete tetraplegic individuals there was a recognizably high percentage of deaths from pneumonia, and among the least disabled individuals (Frankel class E) we found a high frequency of suicides. The Standardised Mortality Ratios (SMRs) were highest for septicaemia, followed by uraemia and pneumonia. A significant decrease in the overall mortality was observed from the first (1953-1973) to the second half of the observation period (1972-1992). Similarly the survival curves for both men and women demonstrate that the gap in survival probability between the normal population and the SCI has diminished considerably from the early to the later period. Likewise, except for suicide and ischaemic heart disease, a decrease in SMRs was seen for all causes of death. In particular there were large decreases related to lung embolus, septicaemia, pneumonia, and uraemia. The patterns of causes of death in the study group begin to approximate those of the general population, though many cause-specific deaths for SCI remain substantially above the normal population. Continuous improvement in preventive measures as well as treatment procedures is still necessary.

Adult↗

PubMed1997

In vivo cell-mediated immunity and vaccination response following prolonged, intense exercise.

Epidemiological and experimental studies have shown increased frequency and severity of infections after intense, long-term exercise. This study examines whether an in vivo impairment of the cell-mediated immunity and antibody production can be demonstrated after intense, long-term exercise. Twenty-two male triathletes performed one-half an ironman (group A). Vaccinations with tetanus and diphtheritis toxoid and purified pneumococcal polysaccharide were given after the exercise. Furthermore, a skin test with seven different antigens was applied on the forearm. Antibody titers were measured before and 2 wk after the exercise. The skin test was read 48 h after the application. Eleven non-exercising triathletes (group B) and 22 moderately trained men (group C) were used as control groups. Group A revealed a significantly lower skin test response to the tetanus antigen than both groups B and C. In group A, a smaller cumulative response (sum of the diameters of indurations and number of positive skin test spots) was found than in both groups B and C. No differences in antibody titers were found among the three groups. Thus, the in vivo cell-mediated immunity was impaired in the first days after prolonged, high intensity exercise, whereas there was no impairment of the in vivo antibody production measured 2 wk after vaccination.

Adult↗

PubMed1996

The immune system and serum glutamine during a triathlon.

This study examined the influence of a triathlon on the immune system and on serum amino acid concentrations. Eight male triathletes swam 2500 m, bicycled 81 km, and ran 19 km. The concentration of total serum amino acids decreased during the race, with the lowest values occurring 2 h postexercise. Similarly, serum glutamine concentration declined from 468 (SEM 24) (prerace) to 318 (SEM 20) mumol-1 (2 h postrace) and the natural killer (NK) and lymphokine activated killer (LAK) cell activities were suppressed 2 h postexercise (P < 0.05). Blood mononuclear cell proliferation decreased during exercise with the lowest value observed after running. The leucocyte concentration increased during and after exercise due to an increase in the concentration of neutrophils and monocytes. There was no significant change in lymphocyte concentration during or after the exercise. The plasma concentration of interleukin-6 did not change and the plasma concentration of interleukin-1 beta and tumor necrosis factor-alpha were below detection limits. The LAK cell cytotoxicity, but not NK cell activity or proliferative response, was significantly correlated with serum glutamine concentrations (r = 0.39, P < 0.01). This study confirms that prolonged endurance exercise results in changes in the cytotoxic function of the NK and LAK cells as well as the proliferative response. The time-course of changes in serum glutamine concentrations were best parallelled by changes in LAK cell activities.

Adult↗

PubMed1995

Spinal cord lesions.

Selected topics related to rehabilitation of individuals with spinal cord lesions are reviewed and commented upon. A 10-week arm-cranking programme improved aerobic capacity and endurance in tetraplegics. Furthermore, endurance training and forced vital capacity were found to be positively correlated. Rowing had additional positive effects for scapular retractor recruitment, which may well improve the shoulder stability. Increased abdominal circumference is an important correlate to dyslipidaemia. beta 2-adrenergic agonists can improve muscle strength and size even without simultaneous exercise. Hydrophilic low-friction catheters, for clean intermittent catheterization have performed as well as, or better than, conventional catheters in a long-term follow-up study. Urethral stenting of the bladder neck and the external sphincter seems, in selected patients, to be an attractive alternative to indwelling urethral catheter drainage or sphincterotomy. The majority (> 80%) of the first 500 sacral anterior root stimulators are still in use for micturition and for defecation. The management of impotence in men with spinal cord lesions using intercavernous injections has been confirmed, and oral terbutaline (5 mg) may be used to achieve penile detumescence in cases of prolonged erection. The use of penile implants in men with spinal cord lesions is a problem. Penile vibration with a peak-to-peak amplitude of 2.5 mm is sufficient to obtain ejaculation in most of these men. Age is more important for sexual adjustment than whether the relationship is established before or after the injury. Regular and frequent follow-up of patients with spinal cord injury is the best way to ensure that post-traumatic syringomyelia is diagnosed and managed (surgically drained) early in order to avoid further disability. Two-thirds of individuals with spinal cord injury rate their quality of life as good. Socialization is important in obtaining a good quality of life. Psychological morbidity in the first 2 years after the injury is found in approximately one-third of the population with spinal cord injury; antidepressant drugs should perhaps be used more widely.

Depressive Disorder↗

PubMed1993

Localization of thermogenesis induced by single infusion of ephedrine in dog.

The localization of the thermogenic effect of ephedrine (1 mg.kg-1 infused intravenously over 10 min.) was studied in 6 fasted dogs anaesthetized with etorfin-acepromazin-N2O. Three experiments were performed in each animal to determine the effect of ephedrine on a) splanchnic oxygen uptake, b) lower leg oxygen uptake and c) the work of the heart. In all experiments whole body oxygen uptake was monitored. Following ephedrine administration the following significant changes were seen as whole body oxygen uptake increased 16%, and splanchnic and lower leg oxygen uptakes increased respectively from 38.4 to 42.3 and from 7.3 to 12.1% of the whole body control oxygen uptake. The pressure-volume work of the heart more than doubled. Significant changes were also seen in mean arterial blood pressure, pulse rate, cardiac output, splanchnic blood flow, and haematocrit and haemoglobin concentration. Plasma glycerol and free fatty acid concentrations increased after ephedrine, and the effects were not elicited by circulating catecholamines.

Animals↗