Faculty Bibliography

In Germany, some 4-6 million men, including 1.2 million diabetics, suffer from erectile dysfunction (ED). Various other diseases including heart disease, hypertension, arteriosclerosis, hyperlipidemia, endocrine disorders, chronic renal insufficiency, prior radical prostatectomy, neurological diseases, trauma and the abuse of alcohol, tobacco, and side effects of medications, are frequently associated with ED. Medical history, clinical examination, routine blood chemistry and sexual hormone levels may help clarify the etiology of ED. Normally, relaxation of the smooth muscles of the corpus cavernosum--mediated by cGMP and cAMP--together with dilatation of penile arteries and occlusion of venous outflow, results in an erection. The oral type V phosphodiesterase inhibitor, Sildenafil, or prostaglandin E1 injection elevates the cGMP and cAMP levels, respectively. Other therapeutic options include mechanical aids, surgery, hormone replacement or sublingual apomorphine. Since 1998, Sildenafil, an effective, simple and safe oral treatment, has been available

STUDY DESIGN: A consecutive and controlled cohort study. OBJECTIVES: To assess the value of motor conduction time (MCT) between cortex and symptomatic leg muscles after transcranial magnetic brain stimulation as an indicator of reversible root ischemia in patients with neurogenic claudication in spinal stenosis. SUMMARY OF BACKGROUND DATA: Neurogenic claudication in spinal stenosis is thought to result from transient ischemia of active nerve root fibers. Subgroups of these patients have slowing of sensory or motor nerve root conduction during spinal claudication. MATERIAL AND METHODS: Forty-two patients with spinal claudication and radiologically confirmed signs of spinal stenosis were consecutively recruited. Motor conduction time was measured before and repetitively after challenge of walking on a treadmill (four stimuli per minute) until disappearance of the symptoms. Data of 30 patients (65 +/- 10 years) with a defined onset of motor-evoked potentials were compared with those of 12 control subjects (62 +/- 12 years). RESULTS: One minute after treadmill challenge, MCT increased in all 13 patients with signs of an exercise-dependent neurologic deficit by at least 1 msec (mean increase, 1.6 +/- 0.6 msec; < 0.001). Test-retest comparisons in six of these patients revealed good reproducibility of the MCT increase (coefficient of repeatability, 1.24 msec). In contrast, MCTs were unchanged or decreased in all 17 patients without exercise-dependent neurologic deficit ( < 0.01) and in the control subjects ( < 0.05). CONCLUSIONS: Measurements of MCT before and after treadmill challenge can demonstrate reversible root ischemia in patients with spinal claudication and exercise-dependent deficit of thickly myelinated nerve root fibers

In familial dysautonomia (FD), cerebral autoregulation (CA) must adjust cerebral blood flow to extreme and rapid fluctuations in systemic blood pressure. Compromised CA during systemic blood pressure (BP) fluctuations might contribute to central autonomic dysfunction in FD.To evaluate CA during rapid BP changes, we monitored heart rate (HR), radial artery BP and middle cerebral artery blood flow velocity (CBFV), using transcranial Doppler sonography, in eight FD patients and twelve age-matched controls in supine position at baseline and during a Valsalva maneuver (VM, 40 mmHg expiratory pressure for 15 seconds). The best of four VM recordings was analyzed. We calculated two autoregulation parameters. CA(II) reflects BP related autoregulatory CBFV increase in late phase II of VM. CA(II) = [(CBFV(II late)-CBFV(II early))/CBFV(II early)]/[(BP(II late)-BP(II early))/BP(II early)]. CA(IV) reflects BP and HR related autoregulatory CBFV increase in phase IV of VM. CA(IV) = (CBFV(IV)/CBFV(I))/(BP(IV)/BP(I))/(HR(IV)/HR(I)). Baseline systemic BP, but not CBFV, was higher in the patients than the controls. During VM, both groups had similar CBFV and BP values, but CAIV and especially CA(II) were significantly lower in the patients than the controls. We have documented that FD patients maintain stable CBFV during rapid BP fluctuations associated with early and late phase II and phase IV of VM suggesting that small intracerebral vessels of FD patients are less responsive to rapid systemic blood pressure fluctuations. To compensate for decreased sympathetic vascular innervation, we propose that FD patients may alter the myogenic component of CA by vessel wall thickening resulting in increased rigidity of intracerebral resistance vessels. The resulting vasoconstriction would allow maintenance of normal baseline CBFV in spite of chronic recumbent hypertension

To improve sensitivity of the analysis of axon reflex flare reaction, the authors used a laser Doppler scanner and analyzed flare intensity and size induced by histamine iontophoresis simultaneously at the foot and thigh in patients with small-fiber neuropathy (n = 10) and controls (n = 9). Flare size, but not laser Doppler flux, clearly distinguished patients from controls at both locations (p < 0.01) and may be useful for evaluation of small-fiber neuropathies

OBJECTIVES: To use the technique of dermal microdialysis to examine sensitivity of skin vessels to noradrenaline (NA) in patients with familial dysautonomia (FD) and in healthy controls. METHODS: In 14 patients with FD and 12 healthy controls, plasma extravasation, local laser Doppler blood flow, and skin blanching were observed before, during, and after application of 10(-6) M NA through a microdialysis membrane, located intradermally in the skin of the lower leg. RESULTS: Maximum local vasoconstriction measured by laser Doppler blood flow did not differ between patients with FD and controls. In contrast, patients with FD had an earlier onset of vasoconstriction (p = 0.02). Moreover, reaction to NA was more prominent and prolonged in FD, shown by a larger zone of skin blanching around the microdialysis membrane (p < 0.001) and delayed reduction of the protein content in the dialysate after termination of NA application (p = 0.03). CONCLUSION: These data support the hypothesis that peripheral blood vessels of patients with FD show a denervation hypersensitivity to catecholamines. This may be one mechanism contributing to the major hypertension that frequently occurs during 'dysautonomic crises' in FD

OBJECT: In ALS patients, autonomic nervous system dysfunction might account for an additional reduction of the quality and expectancy of life of individual patients and contribute to unexpected early fatalities. This study was undertaken to assess baroreflex-mediated vagal and sympathetic cardiovascular control of the heart and blood vessels in ALS patients. METHODS: In 12 early-stage ALS patients (age 54 +/- 4 years) and 12 controls (age 55 +/- 3 years) we assessed resting baroreflex sensitivity (BRS) by spectral analysis, then stimulated the carotid baroreflex by oscillating neck suction at 0.1 Hz to assess the autonomic modulation of the heart and blood vessels and at 0.2 Hz to assess the effect of parasympathetic stimulation on the heart. RESULTS: Resting heart rate was significantly higher in the ALS patients than in the controls (P < 0.05), but resting baroreflex sensitivity did not differ significantly between the groups. Stimulation at 0.2 Hz induced an oscillation in R-R interval that was significantly smaller (P < 0.05) in ALS patients than in controls. R-R interval responses to 0.1 Hz stimulation were significantly (P < 0.01) reduced in ALS patients compared to controls. Responses of blood vessels to 0.1 Hz stimulation did not differ significantly between the groups. CONCLUSION: In early-stage ALS patients, BRS might be normal at rest. Only baroreflex activation reveals impaired cardiovagal responses while sympathetic vasomotor control is preserved. Treatment to restore sympathetic-parasympathetic balance to the heart could prevent early cardiovascular fatalities in some ALS patients

In amyotrophic lateral sclerosis (ALS) patients, hyperintense signals at the subcortical precentral gyrus in brain fluid attenuated inversion recovery (FLAIR) MR images have been found more frequently than in controls. Quantitative analysis has revealed a significant increase of the FLAIR-magnetic resonance imaging (MRI) signal at the subcortical precentral gyrus of ALS patients compared to healthy controls. In addition, hypointense signals at the rim of the precentral gyrus in FLAIR and T2-weighted images have been shown in ALS patients. In 17 ALS patients, we evaluated hyperintense signals in T2-, T1-, proton density-weighted and FLAIR MR images, and hypointense signals in T2-weighted and FLAIR images 15.7+/-3.0 months after the initial examination by visual scoring. In FLAIR images, a quantitative analysis was added. The visual scores of hyperintense signals along the corticospinal tract did not change significantly in all sequences. However, the quantitative evaluation of FLAIR images revealed a significant increase of the signal intensity at the subcortical precentral gyrus (p<0.005). In addition, the frequency of the visually evaluated hypointense signals at the precentral gyrus increased significantly (p<0.05). The change of MR results did not correlate with the change of clinical parameters. In ALS patients, the increase of the quantified MRI signal at the subcortical precentral gyrus in FLAIR images and the increase of hypointense signals at the rim of the precentral gyrus corroborate the hypothesis that these signals are related to the upper motor neuron degeneration in ALS. Their specificity and clinical relevance have to be clarified further

This study was designed to study the influence of gender and lateral hemispheric asymmetry on heart rate modulation during temporal lobe seizures. Heart rate was recorded during complex partial seizures in 10 female and 11 male patients (12 with a right temporal lobe focus, nine with a left focus), with simultaneous video monitoring and bilateral subdural electrode placement. Heart rate changes were analysed during the seizure, at a time when the epileptic activity was restricted to one hemisphere. In this analysed interval, the heart rate of patients with a right temporal lobe focus showed a significant increase, from 73.5 to 91.0 beats/min (F = 10.7, df = 2.3/27, p < 0.001), while the heart rate of patients with a left sided focus only increased slightly, from 77.0 to 82.5 beats/min (NS). An effect of sex was demonstrated, in that the influence of focus laterality could only be shown in male patients (F = 14.24, df = 2.58/27, p < 0.001). These results confirm the right hemispheric lateralisation of sympathetic cardiac control in male patients