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Biomedical subjects

P Berlit

Publications and source records attributed to P Berlit.

At least 37 records · Page 2Linked to original sources
PubMed1998

Percutaneous transluminal angioplasty of intracranial artery stenosis: clinical results in 24 patients.

Circumscribed stenotic lesions of the intracranial arteries can cause cerebral ischemia by hemodynamic and/or thromboembolic mechanisms. Anticoagulation therapy, antiplatelet therapy, and bypass surgery are treatment strategies that have no direct impact on the underlying lesion. This study summarizes the experience of a single institution at which percutaneous transluminal angioplasty (PTA) of intracranial atherosclerotic stenoses was performed. The authors performed a retrospective analysis of 24 consecutive patients. Their medical histories (cardiovascular risk factors, current clinical signs and symptoms and their duration, previous stroke[s], and medical treatment) were evaluated together with findings from previous imaging studies. The site and degree of the stenoses to be treated (target lesion) were identified with the use of ultrasound and angiography studies. Additional vascular stenoses were noted. Percutaneous transluminal angioplasty was performed using single-lumen balloon microcatheters with appropriate diameters. The results of PTA were correlated with angiographic and ultrasound findings and the clinical outcome. Significant cardiovascular risk factors and clinical signs and symptoms related to the target lesion that persisted despite medical treatment were identified in all patients except one. The duration of symptoms varied from several days to 8 months. Previous stroke had occurred in four patients. The degree of stenosis was classified as "high grade" in 10 patients and as "subtotal" in 14. The target lesion (stenosis) was located in the anterior circulation in eight patients (four in the internal carotid and four in the middle cerebral arteries). Stenoses of posterior circulation vessels were treated in 16 patients (nine vertebral, six basilar, and one posterior cerebral arteries). Recanalization was rated "complete" in 15 patients and sufficient in six patients. In three patients residual stenosis remained. Complications were encountered in seven patients: two asymptomatic dissections, one transient vessel occlusion, one vessel occlusion with subsequent stroke, and three ischemic lesions likely due to thromboembolism, two of which caused only transient neurological symptoms. Percutaneous balloon dilation proved effective in the treatment of intracranial atherosclerotic stenosis. There are, however, potential complications and experience with this procedure is only limited. Long-term results need to be determined. The authors conclude from their preliminary results that PTA may be an alternative to bypass surgery and conservative management and may be considered for patients in whom ischemic neurological symptoms persist despite medical treatment.

Journal Article↗
PubMed1998

Spontaneous blood pressure oscillations and cerebral autoregulation.

The relationship between spontaneous oscillations in cerebral blood flow velocity (CBFV) and arterial blood pressure (ABP) was analysed in normal subjects in order to evaluate whether these relationships provide information about cerebral autoregulation. CBFV was measured using transcranial Doppler sonography and continuous ABP and heart rate using Finapres in 50 volunteers. Measurements were made over 5 min in a supine position and 6 min in a tilted position. Coefficients of variation were calculated using power- and cross-spectral analysis in order to quantify amplitudes within two frequency ranges: 3-9 cycles per min (cpm) (M-waves); and 9-20 cpm (R-waves). Correlations, coherence values, phase angle shifts and gains were also computed between corresponding waves in CBFV and in ABP. A clear correlation was seen for M-waves and R-waves between CBFV and ABP and coherence values were large enough to calculate phase angle shifts and gains. Phase angles for M-waves were larger and gains lower than was the case for R-waves, either tilted or supine. These data are consistent with a highpass filter model of cerebral autoregulation. Relatively high CBFV/ABP gain values (between 1.4 and 2.0) suggest that the principle of frequency-dependent vascular input impedances has to be considered in addition to autoregulatory feedback mechanisms. Spontaneous ABP oscillations in the M-wave and R-wave ranges may serve as a basis for continuous autoregulation monitoring.

Adult↗
PubMed1998

[Isolated vertigo in vertebrobasilar ischemia--does it exist?].

An isolated vertigo may occur in vertebrobasilar ischemia, especially as the first symptom of cerebellar ischemia or basilar artery occlusive disease. Based on neuroanatomical findings, these short-lasting vertigo attacks result from transient insufficiency of the anterior inferior cerebellar artery (AICA), which supplies the inner ear and leads to ischemia of the upper parts of the vestibular labyrinth. Persisting vertigo with or without lateropulsion may occur in cerebellar infarctions with involvement of the medial inferior hemispheres due to occlusion of the medial branch of the posterior inferior cerebellar artery. Caloric testing with oculography can usually differentiate cerebellar infarction and peripheral vestibular disease. Since ischemic lesions with AICA insufficiency may cause pathological results in caloric testing, both clinical and neurophysiological analysis of associated oculomotor signs is essential for a correct diagnosis.

Cerebellum↗
PubMed1998

[Clinical application of transcranial color-coded duplex ultrasound for detection of intracranial aneurysms].

We investigated 88 Patients with a total of 102 angiographically diagnosed intracranial aneurysms by means of transcranial colour coded Duplex sonography (TCCD) during a time period of 15 months. Both the size and the localization of the aneurysms were determined. Seventy aneurysms (77%) with a diameter of 16 +/- 8 mm (6-55 mm) were detectable, with excellent visualization in 36 (42%), moderate visualization in 34 (40%), and no sufficient visualization in 16 (16%) aneurysms, respectively. In another 16 cases (16%) there was no sufficient vone window. Thrombotic material inside the aneurysm was detectable in 16/20 cases (75%), visualization of coil embolized aneurysms in 12/25 patients (48%). TCCD allows the follow up of cerebral aneurysms, with the detection of thrombosis and treatment effects after embolization. The method is not valid for the detection of intracranial aneurysms.

Adolescent↗
PubMed1998

Association of resistance to activated protein C and dural arteriovenous fistulas.

Resistance to activated protein C (APCR), shown to be the most common genetic risk factor for venous thrombosis, is mostly caused by a mutation in the factor V (FV) gene leading to FV Leiden. As dural arteriovenous fistulas (DAVFs) are associated with cerebral venous thrombosis, we looked for the FV Leiden mutation in seven patients with such fistulas. The APCR ratio was determined according to standard procedures. For APCR ratios considered pathological (less than 2.0), mutation analysis was done by a reverse hybridization assay. Three of the seven patients with DAVFs showed pathological APCR ratios and heterozygosity for FV Leiden mutation. Thus, it is hypothesized that FV Leiden might be involved in the pathogenesis of DAVFs.

Activated Protein C Resistance↗
PubMed1998

Multiple sclerosis presenting with a Brown-Séquard syndrome.

The Brown-Séquard syndrome as spinal hemiplegia with contralateral sensory deficits has been related to a variety of underlying diseases. We describe the case of a 35-year-old right-handed white female presenting with a Brown-Séquard syndrome as the first and sole symptom of multiple sclerosis, underscoring the importance of multiple sclerosis as a rare condition for the Brown-Séquard syndrome.

Adult↗
PubMed1998

A new 1-MHz probe for transcranial Doppler sonography in patients with inadequate temporal bone windows.

Recent large-scale transcranial Doppler sonography (TCD) studies have revealed that, in 3%-5% of patients, the temporal bone window is insufficient for examination with 2-MHz probes. The diagnostic value of a new 1-MHz probe for TCD was compared with a standard 2-MHz probe in patients with an insufficient ultrasonic window. From a total population of 514 consecutive patients, the study involved only patients in whom a bad or absent temporal bone window was revealed during 2-MHz TCD examination. Fifty patients (39 women and 11 men) with a mean age of 71 +/- 9 y were investigated with a 2-MHz probe and subsequently with a 1-MHz probe. Using the 2-MHz probe, 18 patients (group I) lacked a temporal insonation window bilaterally, while 12 had an absent bone window unilaterally (group II). Twenty patients (group III) had bilateral bone windows, but with insufficient detection of the anterior and posterior cerebral arteries. In four of the 18 patients in group I (22%), the circle of Willis could be demonstrated with the 1-MHz probe. In 11 of the 12 patients in group II (92%), it was possible to demonstrate the contralateral vessels through the ipsilateral bone window with the 1-MHz probe, while this was only possible in 25% with the 2-MHz probe. All 20 patients of group III could be successfully examined with the 1-MHz probe. The 1-MHz probe provides an opportunity to perform TCD studies in older patients presenting with absent or insufficient temporal bone windows for examination with 2-MHz probes.

Aged↗
PubMed1998

Reduced baroreflex sensitivity and cardiorespiratory transfer in amyotrophic lateral sclerosis.

INTRODUCTION: Clinically relevant autonomic disturbances have been reported for respirator-dependent ALS patients while subclinical involvement may be present in the early course. METHODS: Eighteen patients with early-stage ALS and 18 age-matched controls were studied by means of standard autonomic tests (heart off + response to deep breathing and tilt-table testing), and spectral analysis of heart rate (HR) and arterial blood pressure (ABP), using the associated transfer function as a measure of baroreflex sensitivity for the mid-frequency band (MF band, 0.05-0.15 Hz) and as a measure of cardiorespiratory transfer for the high-frequency band (HF band, 0.15-0.33 Hz). RESULTS: Mean HR and ABP were increased in ALS, while results of standard autonomic tests were similar for ALS and controls. Transfer function analysis revealed reduced baroreflex sensitivity and diminished cardiorespiratory transfer during normal breathing. CONCLUSIONS: Cardiovascular autonomic functions are intact in patients with ALS. There is evidence of sympathetic enhancement and vagal withdrawal, accompanied by reduced baroreflex sensitivity. These findings are similar to those reported for essential hypertension and may point to a common central autonomic derangement in both disorders.

Aged↗
PubMed1998

Cerebral embolism and epileptic seizures--the role of the embolic source.

OBJECTIVES: To study the clinical outcome of patients with epileptic seizures due to ischemic stroke (IS) of cardiac or artery-to-artery embolism. METHODS: Seizures due to IS of cardiac or artery-to-artery embolism are differentiated by clinical, neuroimaging and cardiovascular test data. RESULTS: From 174 cases with supratentorial IS, 13 patients suffered from epileptic seizures due to cardiac embolism, 11 patients due to artery-to-artery embolism. The patients with cardiac IS showed an equal sex distribution and EEG abnormalities in 6 patients, the initial seizure occurred on average after 222 days (SD, +/-69 days). Among the 11 patients with artery-to-artery embolic IS, there were 9 males and 2 females and EEG abnormalities in 10 patients. The initial seizure occurred on average after 447 days (SD, +/-177 days). CONCLUSION: In seizures due to artery-to-artery embolism, there is a male preponderance and a higher incidence of EEG abnormalities, symptomatic seizures appear later compared to IS due to cardiac embolism.

Adult↗
PubMed1998

Detection of microemboli distal to cerebral aneurysms before and after therapeutic embolization.

PURPOSE: Recently developed interventional radiologic techniques, such as embolization with platinum coils, may induce thrombus formation within an aneurysm. The aim of the present study was to investigate the frequency of microemboli distal to untreated and treated cerebral aneurysms. METHODS: Among a total of 110 patients treated with platinum coil embolization, 35 patients (27 women and eight men, aged 50+/-10 years) who were at high risk of ischemic complications underwent emboli detection with a transcranial Doppler sonographic monitoring system. All patients were studied before and after coil embolization. The aneurysms were located at the internal carotid artery (n=14), the basilar artery (n=10), the middle cerebral artery (n=7), or the vertebral artery (n=4). Twenty-nine (85%) of 35 patients were monitored within 6 hours of the completion of treatment. RESULTS: Microemboli distal to the aneurysm were not detected in any of the patients before treatment. Microemboli were detected in 11 patients (31%) after embolization (mean, 16+/-21 per hour; range, 1-74 per hour). Microemboli were detected in five (71%) of seven patients in whom ischemic complications occurred after treatment, but in only six (21%) of 28 asymptomatic patients. This difference was statistically significant. The rate of occurrence of emboli in patients with ischemic complications (23+/-30 emboli per hour) was higher than in asymptomatic patients (10+/-7 emboli per hour), but this difference was not statistically significant. CONCLUSION: Microemboli were detected significantly more often in patients who suffered from cerebral ischemia after coil embolization of an intracranial aneurysm. This observation supports the definition of a high-risk group of patients with incomplete embolization or with a large-diameter, broad-neck aneurysm. The early detection of microemboli after treatment may be an indicator for excessive intraaneurysmal thrombus formation and could influence the decision for prophylactic treatment with heparin or aspirin.

Aneurysm↗
PubMed1997

Autonomic evaluation by means of standard tests and power spectral analysis in multiple sclerosis.

Standard autonomic tests [heart rate response to deep breathing (HRDB), change in systolic blood pressure due to tilt], and spectral analysis of heart rate (HR), arterial blood pressure (ABP), and the associated transfer function analysis (gains and phases) were performed in 20 patients with multiple sclerosis to determine their diagnostic value. Transfer function analysis suggested impairment of baroreflex function in 7 patients and an alteration of cardiorespiratory coupling on a brain stem level in 4 patients. In addition, sympathetic vasomotor outflow was reduced in 2 patients (spectral ABP measures in the mid frequency band) and a decrease of vagal outflow was suggested by abnormal respiratory HR parameters in another 2 patients. An abnormal HRDB was present in 5 patients and was probably due to a central alteration (cardiorespiratory coupling) in 2 patients and due to diminished respiratory effort in 1 patient. Spectral analysis of both HR and ABP oscillations and their transfer function may considerably improve the pathophysiological interpretation of cardiovascular autonomic dysfunction in patients with central nervous system disease.

Adult↗
PubMed1997

Sympathetic cardiovascular dysfunction in long-standing idiopathic Parkinson's disease.

Standard autonomic tests (heart rate response to deep breathing--HRDB, heart rate and systolic blood pressure response to tilt--delta HR and delta SBP) and spectral analysis of heart rate and arterial blood pressure and their transfer function (for the mid-frequency band a measure of baroreflex sensitivity) were performed in 20 patients with idiopathic Parkinson's disease (IPD) and 20 age-matched controls. Patients showed significantly diminished delta SBP, and reduced sympathetic vasomotor and cardiomotor outflow (diminished Mayer waves), consistent with an alteration of the efferent arc of the baroreflex. These results were only significant in long-standing IPD (IPD-l, > 5 years), whereas patients with short disease duration (IPD-s, < 5 years) showed values comparable to controls. Respiratory-related heart rate variability was slightly reduced in IPD-1 but this was mainly due to diminished respiratory effort, indicated by low respiratory-related blood pressure variability. We conclude that autonomic abnormalities are only present in long-standing IPD and consist in reduced sympathetic vasomotor and cardiomotor outflow.

Aged↗
PubMed1997

Determinants of heart rate variability during deep breathing: basic findings and clinical applications.

The measurement of heart rate variation during forced breathing (HRDB) is a well-known clinical test of parasympathetic function. It is known that normal values of HRDB are strongly dependent on age. However, little is known about other physiological factors that may lead to reduced HRDB values that may mimic parasympathetic failure. Thirty-two normal subjects (age 56.7 +/- 12.4 years) and 32 neurological patients with pathological autonomic test findings (age 57.9 +/- 10.2) were studied. Oscillations in heart rate and in mean arterial blood pressure were recorded in the supine position during forced breathing (6 cycles/min) using the Finapres monitor. Amplitudes of heart rate and blood pressure waves at 6 cycles/min (HR6 and ABP6) as well as gain values (Gain6 = HR6/ABP6) and phase differences (delta phi 6) between HR and ABP waves were calculated by means of spectral analysis. The mean (+/-SD) HR6 in normal subjects was 6.34 +/- 3.36 cycles/min with a mean ABP6 of 5.11 +/- 2.49 mmHg. HR6 correlated significantly with age (r = -0.426) and with ABP6 (r = 0.602). No significant correlation was found between HR6 and mean blood pressure, mean heart rate or sex. From 24 patients with pathological findings in the classical HRDB value, only nine could be classified as pathological when the effect of ABP6 was considered. In conclusion, ABP variations significantly influence the amplitude of heart rate variations during forced breathing. We interpret these findings in terms of a baroreflex mechanism of HRDB including both vagal and sympathetic efferents. Normal reference value tables for clinical HRDB studies should not only consider age but also the amplitude of blood pressure variations.

Autonomic Nervous System↗
PubMed1997

[Treatment of acute stroke on the stroke unit. Initial experiences with an acute stroke unit in Germany].

We studied the effects of stroke unit care in an acute Neurology department on the outcome and the length of hospital stay in acute stroke patients. After an emergency evaluation on admission including CCT, ultrasound studies and ECG the patients were treated on a specialist stroke unit for an average 3.9 days. For 48 +/- 24 h monitoring of blood pressure, ECG, pO2 and transcranial Doppler sonography was instituted. Stroke unit treatment reduced the length of hospital stay from an average 15.8 days in the time period before institution of the stroke unit to 12.9 days. This effect was especially marked in patients with acute occlusion of major intracranial arteries (before stroke unit treatment: n = 33; hospital stay 22.5 days; after stroke unit treatment: n = 54; hospital stay 13.9 days). Clinical deterioration in acute ischemic stroke was related to reduction of cerebral blood flow velocities due to blood pressure changes or space occupying effects. Monitoring on the stroke unit allowed immediate treatment of systemic hypotension, cerebral edema or cardiac arrhythmias. Transcranial Doppler sonography revealed HITS in 6/55 acute stroke patients without new clinical symptoms. Monitoring on the stroke unit improved the specific care for acute stroke patients. The length of hospital stay was reduced after stroke unit care.

Acute Disease↗
PubMed1997

Dynamic plantar pressure distribution measurements in hemiparetic patients.

OBJECTIVE: A comparison of plantar pressure distribution of hemiparetic patients with a control group was performed to determine quantitative, objective and reproducible criteria for better assessment of hemiparetic gait. DESIGN: This empirical, descriptive study used a clinical sample of 18 hemiparetic patients and compared the data to previously published data from 111 healthy persons. BACKGROUND: Several biomechanical methods have been used in the past to evaluate and classify hemiplegic gait, for example kinetic, cinematographic, or electromyographic systems, but plantar pressure distribution measurement has not been studied. METHODS: Peak pressures were determined under the feet of 18 hemiparetic patients during stance phase using a capacitive pressure distribution platform (EMED-F01 system, Novel GmbH). RESULTS: Hemiparetic patients showed considerably lower peak pressures under all anatomical structures and an unexpected medial load shift in the forefoot. CONCLUSIONS: The grade of spasticity seems to be the most important cause for expression of the medial load shift. Individual pressure distribution gait analysis, as shown in an example, may improve assessment and therapy of hemiparetic patients. RELEVANCE: Plantar pressure distribution data from hemiparetic patients can be used for an analysis of lower extremity dysfunctions. This method may also be employed to assess objectively the success of drug treatment and/or other rehabilitation processes. In particular, individual plantar pressure data from patients will provide additional clinical information for rehabilitation physicians, therapists, and engineers.

Journal Article↗
PubMed1997

Do chronic middle cerebral artery stenoses represent an embolic focus? A multirange transcranial Doppler study.

BACKGROUND AND PURPOSE: It remains uncertain whether the annual stroke risk of 7% to 8% in middle cerebral artery (MCA) stenosis is of embolic or hemodynamic origin. Preliminary reports provide evidence of emboli exiting from acute MCA stenoses, detected by transcranial Doppler (TCD) sonography. With multirange monitoring before and after the stenosis, TCD monitoring may help for the first time to differentiate microemboli exiting from the MCA stenosis from those with a source proximal to the MCA stenosis. We searched for microembolic signals (MES) using multigated monitoring in patients with chronic MCA stenoses. METHODS: Fifty-eight patients with 78 chronic stenoses of the MCA were enrolled in the study. Additional sources of embolism were ruled out by extensive clinical workup. Twenty-four patients were treated with coumarin, whereas 28 patients received aspirin. The remaining 6 patients discontinued their medication after a few weeks. The sample volume of the multirange probe was placed on either side of the stenotic area of the MCA. RESULTS: Twenty-three (29.5%) of the stenoses were low grade, 18 (23%) were moderate, and 37 (47.5%) were severe. Thirty-seven (47%) of the stenoses were symptomatic and 41 (53%) were asymptomatic before study entry. During follow-up, 2 strokes and 7 transient ischemic attacks occurred. Computer tomography revealed two watershed-type infarcts. Sufficient insonation of the prestenotic and poststenotic segments of the MCA was possible in 70 stenoses (90%). No MES could be detected during a total of 1740 minutes' monitoring time distal to the MCA stenoses, regardless of the patients' medication. MES were also absent in the contralateral MCA. CONCLUSIONS: MES are not detectable in patients with chronic MCA stenoses of different degrees. No MES were found in either symptomatic or asymptomatic stenoses, regardless of the patients' medication. These results indicate that chronic MCA stenoses do not represent a significant embolic source. The absence of MES in the prestenotic Doppler sample volume, the watershed-type infarcts during follow-up, and the absence of small-vessel disease on computed tomography suggests that hemodynamic mechanisms are responsible for recurrent cerebral ischemia.

Aged↗
PubMed1997

Effect of biotin depletion on spike-wave seizures in the tottering mutant mouse.

Influence of depletion of biotin on spontaneously occurring spike-wave seizures in the tottering mutant mouse was tested by electrocorticographic recordings over three hours in five mice fed a biotin deficient diet. Frequency of seizures as well as percent of time with epileptic discharges were clearly lowered in the biotin deficient animals compared with eight mice of the same age under normal food (p < 0.01 in Wilcoxon's U-test).

Animals↗