[Sports medical aspects in cardiac risk stratification--heart rate variability and exercise capacity]

The present study investigates the association of the predicted CHD-risk (PROCAM) with the individual endurance capacity and heart rate variability (HRV) in a population-based sample of sedentary elderly. After stratification, in 57 men (48.1+/-9.5 yrs.) with an overall PROCAM-risk <10% (28.7+/-10.9 points) and 22 men (54.5+/-7.7 yrs.) with a coronary 10-year risk > or =10% (50.8+/-5.6 points) cycle ergometries and short-term HRV analysis of time (RRMEAN, SDNN, RMSSD) and frequency domain parameters (LF, HF, TP, LF/HF) were conducted. Additionally the autonomic stress index (SI) was calculated. Nonparametric tests were used for statistical correlation analysis (Spearman rho) and group comparisons (Mann-Whitney). For endurance capacity [W/kg] (r=-0.469, p<0.001), SDNN (r=-0.302, p<0.05), RMSSD (r= -0.311, p<0.05), LF (r=-0.325, p<0.05), HF (r= -0.311, p<0.05) and TP (r= -0.307, p<0.05) negative monotone correlations with the coronary score-risk were determined. Significant positive correlations were calculated for SI (r=0.476, p<0.001). Except for RRMEAN and LF/HF significant group differences (p<0.05) were computed for SDNN (30.0+/-20.0 vs 20.0+/-10.0 ms), RMSSD (22.2+/-18.3 vs 18.0+/-8.7 ms), LF (90.9+/-241.5 vs 41.35+/-81.1 ms(2)), HF (43.0+/-105.1 vs 18.0+/-27.0 ms(2)) and TP (189.0+/-457.1 vs 100.0+/-157.6 ms(2)). Significant differences (p<0.01) were evaluated for exercise capacity (2.4+/-0.5 vs 1.8+/-0.3 W/kg) and SI (90+/-183 vs 322+/-291). The results underline the predictive value of HRV analysis in risk stratification and outline the interrelation of a decreased exercise capacity and autonomic function with a raised individual 10-year cardiac risk. As an independent parameter of the vegetative regulatory state the stress index may contribute to an increased practical relevance of short-time HRV analysis.

Occult, life-threatening, cardial tumor in syndactylism in Gorlin Goltz syndrome

Pediatric, orthopedic, plastic, and hand surgeons perform the surgical correction of syndactylism. It is sometimes forgotten, however, that syndactylism can be part of a syndrome. The components of such a syndrome can each be life threatening. A 7-month-old boy was hospitalized for correction of cutaneous syndactylism. The mother claimed that, with the exception of the syndactylism, her son was healthy. However, review of the admission documents found that the family physician suspected Gorlin Goltz syndrome. A preoperative echocardiography showed 3.9-cm intramural tumor in the wall of the left ventricle. Electrocardiography documented ventricular tachycardia. Because of the danger of life-threatening malignant ventricular tachycardia, the tumor was resected. Before the resection, cardiac transplantation was considered because of the size of the tumor. Histologic examination found a fibroma. When observing syndactylism, one must always be aware of the possibility of a syndromic disease. It is particularly important that screening investigations, including electrocardiography and echocardiography, are performed before surgical treatment.

Renoprotection by blockade of the renin-angiotensin-aldosterone system in diabetic and non-diabetic chronic kidney disease. Specific involvement of intra-renal angiotensin-converting enzyme activity in therapy resistance?

Data of numerous clinical trials show that lowering of blood pressure is prerequisite for reducing the rate of renal function loss in chronic renal disease. There is evidence supporting that blood pressure lowering obtained by intervention in the renin-angiotensin-aldosterone system (RAAS) has an additive renoprotective effect over reduction of blood pressure alone, both in diabetic and non-diabetic renal diseases. The main evidence for renoprotective action of RAAS blockade is provided by its consistent antiproteinuric action, which cannot completely be attributed to the reduction in blood pressure. Indeed, proteinuria reduction during therapy is the single most important factor predicting the renal prognosis, independent from the class of drugs used. Yet, still patients progress to end-stage renal disease. In this review, individual differences in therapy response and possibilities to overcome therapy resistance to RAAS blockade are discussed. Experimental data from studies in rats suggest a specific involvement of intrarenal factors, particularly of preexisting renal damage and renal angiotensin-converting enzyme (ACE) activity, in therapy resistance. Identification of such factors in individual renal patients provides mechanisms by which renoprotective strategies fail to overcome therapy resistance. This prompts for a dual approach to improve renoprotection, namely unravelling these specific intrarenal mechanisms on the one hand, and development of better strategies for early detection of renal risk on the other hand.

Walking patterns of hip arthroplasty patients: some observations on the medio-lateral excursions of the trunk

PURPOSE

This study examined the angular gait kinematics of the trunk and the pelvis in the frontal plane and their amount of side-to-side asymmetry in patients after total hip replacement arthroplasty.

METHOD

The angular gait kinematics of 12 male hip arthroplasty patients (53-70 years) were compared to ten age-matched and ten young (24-35 years) male control subjects. Average step times and medio-lateral oscillation amplitudes of the pelvic and thoracic recordings were calculated for each step. Between successive steps the asymmetry ratio was computed and the mean angle around which the side-to-side oscillations occurred was compared to the angle in a symmetrical standing trial.

RESULTS

ANOVA indicated no significant side differences in relative step cycle durations. Patients and senior controls had significantly (p<0.01) less pelvis side-to-side displacements than the younger controls. No significant between-group differences could be detected for the average asymmetry ratio. However, during walking the patients showed a significantly (p<0.01) increased lateral thorax and pelvis deviation.

CONCLUSIONS

Hip replacement patients' thoracic and pelvic position is characterized by a lateral shift throughout the gait cycle, while left and right symmetry of angular movements amplitudes remain at about the same value of unimpaired subjects.

[EMG analysis of shoulder muscles during preventive and therapeutic exercise in the overhead athlete]

Strengthening of the rotator cuff muscles in functional positions is one of the important demands in the prevention and rehabilitation of overhead athletes. The purpose of this study was to evaluate the influence of a new shoulder bar (SBT 1000) on the myoelectric activity of the deltoid muscle. Subjects included 12 healthy overhead athletes (control group) and 9 overhead athletes with subacromial pain syndrome (test group). Both groups performed bilateral internal and external shoulder rotations against resistance from a pulley. The position of 90 degrees abduction and elbow flexion was passively supported with the SBT 1000 and had to be actively hold without the SBT 1000. The electromyographic activity of the three heads of the deltoid was determined using surface electrodes. Rectified mean EMG data were analysed by three factor repeated measures ANOVA (group x bodyside x condition). Significant differences (p < 0,05) occurred between the conditions with and without SBT 1000 in all three heads of the deltoid. The percentage of reduction of muscle activity with the SBT 1000 in the dominant arm was 33 %, 29 % and 17 % for the anterior, middle and posterior head. No significant differences could be shown between control and test group or between the dominant and nondominant arm. With the SBT 1000 rotational shoulder exercise can be performed in a functional position with reduced involvement of the deltoid, which could be beneficial in prevention and rehabilitation of overhead athletes.

Neuromuscular control of walking with chronic low-back pain

The reported association of low-back pain and musculoskeletal disorders contributed to the examination of the lumbar spine and hip extensor activation patterns in back pain sufferers during walking. Seventeen idiopathic low-back pain male subjects and 16 healthy volunteers participated in the study. Hip joint ROMs in the sagittal plane and neuromuscular activities of erector spinae [L3, T12], gluteus maximus and biceps femoris were recorded on one randomly selected body side in each group. Analysis using the Student's t-test revealed significant differences for hip joint range of motion, stride time and significantly earlier onsets of the lumbar spine and hip extensors of the back pain sufferers compared with the healthy controls. It is assumed, that low-back disorders are related to changes of the lumbar spine and hip extensor recruitment pattern.

[Gait disorders - assessment and rehabilitation supported by movement analysis]

AIM

The present paper validates the use of two-dimensional pelvis and thorax translation data for the assessment of gait disturbances and evaluates the effects of a real-time visual feedback system based on thoracic spine kinematics for gait rehabilitation.

METHODS

To validate the use of two-dimensional gait kinematics, vertical and horizontal displacements of pelvis (S1) and thorax (T12) markers of the twelve healthy individuals (25.9 +/- 2.7 years) were recorded during two gait perturbations: a brace constraining the knee to 30 degrees of flexure and a shoe lift of 3 cm. To investigate the effects of verbal instructions and additional real-time visual feedback on vertical and medial-lateral pelvis and trunk movements, gait kinematics were recorded during three randomized trials (verbal instruction, real-time visual kinematic feedback, free walking).

RESULTS

Gait deviations did result in significant (p < 0.05) increases of horizontal and vertical trunk pelvis movements. Significant (p < 0.05) reductions in oscillation amplitudes were noted when verbal cues and visual information were received. However, the major decrease occurred during real-time visual feedback.

CONCLUSION

Asymmetric limping, similar to gait disorders of individuals with hip pathologies, could be detected and described by two-dimensional thorax and pelvis translation data. It could be speculated that gait disorders may be addressed by real-time kinematic feedback training.

Comparison of angular lumbar spine and pelvis kinematics during treadmill and overground locomotion

OBJECTIVE

To determine the differences between angular oscillation curves of the lumbar spine and pelvis during walkway and treadmill ambulation.

DESIGN

An in vivo observation of walking in overground and treadmill conditions.

BACKGROUND

Angular movements of the lumbar spine and pelvis have been obtained during overground and treadmill walking. No data are available to indicate whether lumbar spine treadmill findings may be compared or generalized to overground readings.

METHODS

Nine male subjects walked at their natural cadence along an 8 m walkway positioned over a motorized treadmill. During each of 20 walking trials, kinematic data of one full gait cycle were collected in the middle segment of the walkway. Following the overground readings the walkway was removed and treadmill recordings were taken at the subjects' preferred walking speed and at an imposed speed of 1.25 m/s. Movement patterns and maximum oscillation angles were calculated in each plane.

RESULTS

Cross-correlation values of pairwise comparisons demonstrated almost comparable movement patterns between walking conditions (r > or =0.891; p<0.001) except for the movement in the sagittal plane (r=0.642, p<0.01). ANOVA for repeated measures revealed significant (p<0.05) differences in the gait cycle duration as well as reductions in oscillation amplitudes of the upper lumbar region and the pelvis in both the frontal and transverse plane during treadmill walking compared to walkway locomotion.

CONCLUSIONS

Statistically significant differences exist for some angular lumbar spine movement parameters between walkway and treadmill locomotion.

RELEVANCE

The observed differences between overground and treadmill locomotion should be taken in account when treadmill-based lumbar spine and pelvis kinematics want to be extended or compared to overground recordings.

Influences of nonspecific low back pain on three-dimensional lumbar spine kinematics in locomotion

STUDY DESIGN

A three-dimensional kinematic analysis of lumbar spinal movements with an ultrasonic measuring system was used to distinguish patients with chronic low back pain from those without such pain.

OBJECTIVES

To investigate the effects of chronic low back pain on the three-dimensional movements of the lumbar spine, and to identify variables that would allow discrimination among patients with chronic low back pain and control subjects.

SUMMARY OF BACKGROUND DATA

To the authors' knowledge, no previous studies have described or identified altered spinal and pelvic gait kinematics caused by nonspecific chronic low back pain in all anatomic planes.

METHODS

In this study, 34 participants with chronic low back pain and 22 subjects without such pain were monitored during treadmill gait. Data from the measuring system operating at 30 Hz were low-pass filtered and normalized to a percentage of the gait cycle.

RESULTS

Cross-correlations showed almost identical patterns of pelvic (S1) and thoracic (T12) movement curves in all anatomic planes between groups. No statistical group differences were detected for either pelvic or thoracic oscillation amplitudes. However, Student's t test showed significantly higher coefficients of variation (P < 0.01) in all anatomic planes of patients with chronic low back pain than in healthy control patients.

CONCLUSIONS

The phasic patterns and angular spinal displacements of patients with nonspecific low back pain were shown to be within normal limits. However, the patients demonstrated higher degrees of stride-to-stride variability, representing increased fluctuations in dynamic thoracic and pelvic oscillations. These findings, resulting in less than optimal gait patterns, must be considered in the rehabilitation of patients with chronic low back pain.

Sorting and directed transport of membrane proteins during development of hippocampal neurons in culture

Hippocampal neurons in culture develop morphological polarity in a sequential pattern; axons form before dendrites. Molecular differences, particularly those of membrane proteins, underlie the functional polarity of these domains, yet little is known about the temporal relationship between membrane protein polarization and morphological polarization. We took advantage of viral expression systems to determine when during development the polarization of membrane proteins arises. All markers were unpolarized in neurons before axonogenesis. In neurons with a morphologically distinguishable axon, even on the first day in culture, both axonal and dendritic proteins were polarized. The degree of polarization at these early stages was somewhat less than in mature cells and varied from cell to cell. The cellular mechanism responsible for the polarization of the dendritic marker protein transferrin receptor (TfR) in mature cells centers on directed transport to the dendritic domain. To examine the relationship between cell surface polarization and transport, we assessed the selectivity of transport by live cell imaging. TfR-green fluorescent protein-containing vesicles were already preferentially transported into dendrites at 2 days, the earliest time point we could measure. The selectivity of transport also varied somewhat among cells, and the amount of TfR-green fluorescent protein fluorescence on intracellular structures within the axon correlated with the amount of cell surface expression. This observation implies that selective microtubule-based transport is the primary mechanism that underlies the polarization of TfR on the cell surface. By 5 days in culture, the extent of polarization on the cell surface and the selectivity of transport reached mature levels.