Andreas Hartkopp

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.

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) μmoll−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-1β and tumor necrosis factor-α 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.

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.

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.

Effect of training on contractile and metabolic properties of wrist extensors in spinal cord-injured individuals.

Paretic human muscle rapidly loses strength and oxidative endurance, and electrical stimulation training may partly reverse this. We evaluated the effects of two training protocols on the contractile and metabolic properties of the wrist extensor in 12 C‐5/6 tetraplegic individuals. The wrist extensor muscles were stimulated for 30 min/day, 5 days/week, for 12 weeks, using either a high‐resistance (Hr) or a low‐resistance (Lr) protocol. Total work output was similar in both protocols. The nontrained arm was used as a control. Maximum voluntary torque increased in the Hr (P < 0.05) but not the Lr group. Electrically stimulated peak tetanic torque at 15 HZ, 30 HZ, and 50 HZ were unchanged in the Lr group and tended to increase only at 15 HZ (P < 0.1) in the Hr group. Resistance to fatigue, however, increased (P < 0.05) in both Hr (42%) and Lr (41%) groups. Muscle metabolism was evaluated by 31P nuclear magnetic resonance spectroscopy (31P‐NMRS) during and following a continuous 40‐s 10‐HZ contraction. In the Hr group the cost of contraction decreased by 38% (P < 0.05) and the half‐time of phosphocreatine (PCr) recovery was shortened by 52% (P < 0.05). Thus, long‐term electrically induced stimulation of the wrist extensor muscles in spinal cord injury (SCI) increases fatigue resistance independent of training pattern. However, only the Hr protocol increased muscle strength and was shown to improve muscle aerobic metabolism after training. Muscle Nerve 27: 72–80, 2003

Training by low-frequency stimulation of tibialis anterior in spinal cord-injured men

The tibialis anterior muscle of nine paraplegic men was chronically stimulated (2–6 h per day; at 10 Hz, 5 s on, 5 s off) under isometric loading conditions for 5 days per week for 4 weeks. After 4 weeks of training, muscle fatigue resistance in an electrically evoked test had increased by an average of 75% (P < .01, n = 9), but there were no changes in the relative composition of the three myosin heavy chain (MHC) isoforms. Five of the subjects continued training for an additional 5 weeks (2 h per day, 3 days per week). Although there was a tendency for twitch time to peak torque to increase after this additional period, no change occurred in relative MHC isoform content. However, in situ hybridization analysis revealed that even after 2 weeks of stimulation, there was evidence of upregulation of the mRNA for the MHC‐I isoform and downregulation of the MHC‐IIX isoform, a development that continued in weeks 4 and 9. This study provides evidence, at the level of gene transcription, that a fast‐to‐slow change in MHC isoform composition may be possible in human muscle when its usage is significantly increased.

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.

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.