Max-Josef Hilz

MRI-FLAIR images of the head show corticospinal tract alterations in ALS patients more frequently than T2-, T1- and proton-density-weighted images

In some patients with amyotrophic lateral sclerosis (ALS), T2-weighted and proton-density-weighted magnetic resonance imaging (MRI) shows hyperintense or hypointense signals at the corticospinal tract. Fluid-attenuated inversion recovery (FLAIR) sequences increase the sensitivity of MRI to detect cortical and subcortical tissue changes. In 31 ALS patients and 33 controls, we studied the frequency and the extent of signal abnormalities in FLAIR images compared to T2-, T1- and proton-density-weighted images. Hyperintense signals at the corticospinal tract were significantly more frequent in FLAIR images than in all other tested sequences. In FLAIR images of ALS patients only, distinct hyperintense signals at the subcortical precentral gyrus (five patients), the centrum semiovale (eight patients), the crus cerebri (nine patients) and the pons (four patients) as well as mild hyperintense signals in the medulla oblongata (three patients) were seen. More frequently, but not exclusively in ALS patients, FLAIR images showed mild hyperintense signals at the subcortical precentral gyrus (15 patients vs. 1 control). Quantitative analysis confirmed the significant difference between ALS patients and controls at the subcortical precentral gyrus in FLAIR images. In T1-weighted images, the corticospinal tract at the capsula interna was hypointense in significantly more controls than ALS patients. Also this difference was confirmed in the quantitative analysis. Similar to previous results, MR image alterations did correlate poorly to clinical data of upper motor neuron affliction.MR images of the head, including FLAIR images, provide additional information regarding corticospinal tract involvement in ALS patients. Because of an overlap with physiological findings, they have to be interpreted cautiously, with the exception of hyperintense signals at the subcortical precentral gyrus.

Hyperintense and hypointense MRI signals of the precentral gyrus and corticospinal tract in ALS: A follow-up examination including FLAIR images

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.

Effects of age on the cardiac and vascular limbs of the arterial baroreflex

Background Healthy ageing has several effects on the autonomic control of the circulation. Several studies have shown that baroreflex‐mediated vagal control of the heart deteriorates with age, but so far there is little information regarding the effect of ageing on sympathetically mediated baroreflex responses. The aim of this study was to assess the effects of ageing on baroreflex control of the heart and blood vessels.

Peripheral neuropathy in chronic venous insufficiency

Chronic venous insufficiency (CVI) of the lower legs may cause tissue damage, but involvement of peripheral nerves is uncertain. We examined 30 patients with CVI and 20 healthy controls using motor and sensory nerve conduction studies, vibration testing and thermotesting, quantitative sudomotor axon‐reflex test, and laser Doppler flowmetry. Subjects with possible confounding factors for peripheral neuropathies were excluded. Prolongation of distal motor latency of the peroneal nerve (median, 5.4 versus 4.5 ms; P = 0.02), increased limits for warm (9.60°C versus 5.20°C; P = 0.016) and cold detection (3.45°C versus 1.55°C; P = 0.016) and reduced vibration sense (2.8925 versus 1.1075; P < 0.008) were found. The results demonstrate a disturbance of A‐alpha fibers, A‐beta fibers, A‐delta fibers, and thermoafferent‐C fibers, possibly induced by ischemia due to venous microangiopathy and increased endoneurial pressure. Analogous to neuropathic ulcers in diabetes, the CVI‐associated neuropathy may also be a cofactor in the development of venous ulcers.

Impairment of parasympathetic baroreflex responses in migraine patients

Objectives –  The aim of this study was to assess baroreflex regulation of the heart rate and blood vessels in migraine patients in comparison with healthy controls.

Enhanced external counterpulsation improves skin oxygenation and perfusion.

Background  Enhanced external counterpulsation (EECP) augments diastolic and reduces systolic blood pressures. Enhanced external counterpulsation has been shown to improve blood flow in various organ systems. Beneficial effects on skin perfusion might allow EECP to be used in patients with skin malperfusion problems. This study was performed to assess acute effects of EECP on superficial skin blood flow, transdermal oxygen and carbon dioxide pressures.

Vestibular evoked blood flow response in the basilar artery

Background and purpose‐ Monitoring of the basilar artery (BA) is difficult and has been sparsely performed. The aim of this study was to present physiological data of functional transcranial Doppler sonography (TCD) of the BA during caloric vestibular stimulation in healthy volunteers. Methods ‐ TCD of the BA was performed in 26 healthy volunteers (14 women, 12 men, age 25.1 ±3 years) during caloric vestibular stimulation. Vertigo was documented using electronystagmography (ENG) and a subjective vertigo scale ranging from 0 to 10 points. Simultaneously, capnogpraphy was performed. Results ‐ All subjects experienced vertigo, nausea and oszillopsia during vestibular irrigation. The average subjective vertigo was for a period of 106 s (±65.4); the average subjective estimated degree of vertigo was 6.7 points (±1.5). In all subjects, ENG demonstrated horizontal nystagm to the left non‐irrigated side. In 14 subjects the subjective vertigo was rated by the individuals as extreme (point score ≥ 7) and in 12 subjects as low (point score <7). Mean flow velocity (MFV) in the BA increased significantly during vestibular irrigation, being more prominent in the initial irrigation and vertigo phase (5.8±5.9%, P<0.05) than in the second vertigo phase (2.2 ±8.8%, P<0.05). The calculated pulsatility index (PI), which indicates the condition of the small resistance vessels, decreased significantly (‐4.9±8.1%; −4.3±8.9%, P<0.05) during both phases of vestibular activation. Endtidal pCO2 did not change significantly (constant 5.4±0.4 Vol%), but respiration frequency was significantly increased during vestibular stimulation (12.3±3.8 min‐1 to 16.4±5.3 min‐1 and 16.3±4.8 min‐1, P<0.05) probably as a vegetative sign of vertigo. The observed MFV‐ and Pi‐changes were more prominent, although not quite significant, in the subgroup of subjects who experienced extreme subjective vertigo than in the subgroup who experienced low subjective vertigo. Conclusion ‐ These observations indicate that MFV increase in the posterior circulation is due to activation of the vestibulocerebellum. In addition, it is possible that the previously elaborated MFV increase in the MCA might contribute to MFV increase in the BA via the posterior communicating artery. The difference in the 2 subgroups (extreme vertigo vs low vertigo) may reflect the great variety of anatomical and physiological conditions of the peripheral vestibular organ, the brainstem anatomy and the corresponding blood supply. For clinical purposes this TCD‐test may contribute to the investigation of the vasomotor reserve of the posterior circulation, e.g. in patients with vertebrobasilar ischemia, bilateral vestibular loss or local neurodegenerative disease.

Increased hypoxic blood pressure response in patients with amyotrophic lateral sclerosis

OBJECTIVES There is evidence of impaired cardiovascular autonomic control and reduced baroreflex sensitivity in patients with amyotrophic lateral sclerosis (ALS). A compromised baroreflex-chemoreflex interaction might result in inadequate responses to chemoreflex activation with progressive hypercapnia and hypoxia and contribute to early fatalities. This study was performed to assess cardiovascular and ventilatory responses to hypercapnic and hypoxic stimulation in ALS patients with impaired baroreflex function. PATIENTS AND METHODS In 15 ALS patients with previously demonstrated baroreflex dysfunction and in 15 age-matched controls, we compared electrocardiographic RR-interval (RRI), systolic blood pressure (SBP) and minute ventilation (VE) during normal ventilation and during selective progressive hypoxia and hypercapnia. RESULTS Ventilatory and RRI responses to hypoxic and hypercapnic stimulation as well as SBP responses to hypercapnia did not differ between patients and controls. In contrast, hypoxia induced a significant SBP increase in patients only. CONCLUSIONS The normal ventilatory and RRI responses to chemoreflex activation suggest intact afferent chemoreflex function. The hypertensive response to hypoxia might be due to a compromised interaction with the baroreflex. Avoiding hypoxic episodes might reduce the risk of cardiovascular crisis in ALS patients.

Cadmium- und Kupferausscheidung nach Aufnahme von Champignon-Mahlzeiten

High contents of cadmium in some agaricus species led to the warning that the eating of wild-grown mushrooms may bear the possibility of cadmium-intoxication. The low digestion rate due to the chitin membrane of fungi was not discussed. Therefore, in this investigation the cadmium- and copper-concentrations in feces of five subjects were estimated before and after a three days mushrooms diet. The high amount of fecal cadmium and copper increasing after the diet confirm the suggestion, that eaten fungi mostly pass through the intestinal tract unscathed without resorption. By this even larger ingestions of agaricus fungi may not cause cadmium intoxication in humans.SummaryHigh contents of cadmium in someagaricus species led to the warning that the eating of wild-grown mushrooms may bear the possibility of cadmium-intoxication. The low digestion rate due to the chitin membrane of fungi was not discussed. Therefore, in this investigation the cadmium- and copper-concentrations in feces of five subjects were estimated before and after a three days mushrooms diet. The high amount of fecal cadmium and copper increasing after the diet confirm the suggestion, that eaten fungi mostly pass through the intestinal tract unscathed without resorption. By this even larger ingestions ofagaricus fungi may not cause cadmium intoxication in humans.ZusammenfassungDer Nachweis holier Cadmium-Konzentrationen in einigen wildwachsenden Champignon-Arten hatte zu Warnungen vor der möglichen Gefahr einer Cadmium-Intoxikation durch Aufnahme der Pilze geführt. In den Untersuchungen blieb unberücksichtigt, daß höhere Pilze im menschlichen Darm kaum verdaut werden können.Von 5 Probanden, die drei Tage eine Champignondiät aufgenommen hatten, wurden daher Stuhlproben vor und nach der Pilzdiät auf ihren Cadmium- und Kupfergehalt untersucht. Die in den Faeces nachgewiesenen hohen Schwermetallkonzentrationen bestätigten die Annahme, daß Speisepilze, deren Gerüstsubstanz, das Chitin, enzymatisch nicht angreifbar ist, weitgehend unverdaut den Darm passieren, ohne daß es zu einer wesentlichen Resorption kommt. Daher scheint die Gefahr einer Cadmium-Intoxikation auch nach Aufnahme großer Champignon-Mahlzeiten für den Menschen nicht gegeben.

Transcranial Doppler sonography–ergometer test for the non-invasive assessment of cerebrovascular autoregulation in humans

Cerebrovascular hemodynamics during physical stress have been sparsely investigated, mostly through risky invasive techniques. The aim of this study was to determine the effect of ergometer stress on cerebrovascular hemodynamics in humans using the non-invasive and thus clinically-applicable method of transcranial Doppler sonography (TCD) combined with simultaneous non-invasive measurements of cardiovascular parameters. In eighteen healthy subjects (six women, twelve men; 29.3+/-4.6 years old) left midcerebral artery blood flow velocities (CBFVs) were continuously monitored using TCD during 3 min at rest, 3 min during ergometry and 3 min recovery. Simultaneously, systolic, diastolic, mean CBFVs, pulsatility index (PI), heart rate, beat-to-beat blood pressure (BP) and transcutaneous p(CO(2)) were measured. The subjects were supine with elevated trunk. Ergometry was performed by pedalling a Mühe-ergometer. In eight volunteers, the procedure was repeated within the next day to test the repeatability of the results. Heart rate increased significantly during ergometry (from 65.2+/-11 to 105. 3+/-12.3/min; P<0.05). The systolic BP increased significantly slightly later during ergometry (from 118.9+/-8.6 to 141.6+17.9 mmHg; P<0.05). Transcutaneous p(CO(2)) was initially within physiological ranges, but increased significantly after a delay during the 3rd min of cycling (from 39.7+/-3.7 to 41.1+/-4.7 mmHg; P<0.05). MFV started to rise significantly after 1 min of the exercise period (from 59.6+10.9 to 68.3+13.9 cm/s; P<0.05). PI increased immediately and significantly at the start of exercise (PI at rest 0.93+0.11; PI ergometry 1.1+0.13; P<0.05). The results were found to be reproducible in the eight volunteers. The cerebrovascular changes during ergometer exercise may reflect the combined activation of the cerebrovascular autoregulative mechanisms (neurogenic, myogenic and metabolic). The TCD-ergometer test presented here is non-invasive and would seem to present a low risk for patients who are judged fit enough for mild exercise. The test may contribute to the detection of cerebrovascular abnormalities in various diseases.