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Biomedical subjects

M Daffertshofer

Publications and source records attributed to M Daffertshofer.

54 records · Page 3Linked to original sources
PubMed1994

Proinflammatory cytokines in serum of patients with acute cerebral ischemia: kinetics of secretion and relation to the extent of brain damage and outcome of disease.

The release of the proinflammatory cytokines IL-1 beta, IL-6, TNF-alpha and soluble TNF-receptors p55 and p75 in peripheral blood was serially determined in 19 patients with acute cerebral ischemia. Only patients admitted within 4 h following onset of symptoms were studied. In contrast to serum levels of IL-1 beta, TNF-alpha and TNF-receptors, which did not exhibit a significant response, IL-6 showed a significant increase of serum levels already within the first hours following onset of disease and reached a plateau at 10 h until day 3 and returned to baseline by day 7. The increase of levels of this cytokine was significantly (P < 0.05) correlated with increasing volumes of brain lesion and was also significantly (P < 0.005) associated with poor functional and neurological outcome. The increase of levels of IL-6 despite a considerable dilution in peripheral blood shown in this preliminary study suggests an early inflammatory response in ischemic brain lesion.

Activities of Daily Living↗
PubMed1994

Pattern of activation of the hypothalamic-pituitary-adrenal axis in acute stroke. Relation to acute confusional state, extent of brain damage, and clinical outcome.

BACKGROUND AND PURPOSE: The aim of this study was to characterize the response of the hypothalamic-pituitary-adrenal system in the first hours of ischemic stroke and to relate its extent to the occurrence of acute confusional state, volume of brain damage, and clinical outcome. METHODS: The secretion of corticotropin (adrenocorticotropic hormone [ACTH]) and cortisol was studied in 23 patients by determinations at hours 4, 6, 8, 10, and 14 and days 1, 3, 5, and 7 after onset of symptoms. Acute confusional state (DSM-III-R criteria), extent of lesion (volumetry of computed tomographic scans), and neurological and functional outcome (Scandinavian Stroke Scale, Barthel Index scores) were assessed. RESULTS: The massive neuroendocrine response observed consisted of an initial phase with concomitantly increased levels of ACTH and cortisol and a second phase with decreased levels of ACTH while high concentrations of cortisol persisted. Initial levels of ACTH but not cortisol were significantly increased in patients with acute confusional state and significantly correlated with volume of brain lesion and neurological and functional outcome. CONCLUSIONS: An early and persisting activation of the hypothalamic-pituitary-adrenal axis was observed in relation to severity of disease. Its characteristic biphasic pattern suggests an initial central stimulation of release of ACTH followed by feedback suppression concomitant with an increased susceptibility of the adrenal gland. Because these hormones are known to exacerbate hypoxic injury to neurons, their massive release in hyperacute stroke may increase the extent of brain damage.

Acute Disease↗
PubMed1994

Assessment of local sympathetic function in patients with erectile dysfunction.

Fifty men with erectile dysfunction (ED) were urologically investigated for autonomic deficit by evaluation of the sympathetic skin response at the penis. They were additionally subjected to thorough urological, vascular, psychiatric and neurological examinations, and well-established neurophysiological tests of the somatosensory, sympathetic, and parasympathetic function. Patients with clinical evidence of neurological deficit showed abnormal results (68%) in at least one test of the autonomic nervous system. The sympathetic skin response at the penis was absent in 11 cases (37%) with clinical evidence of neuronal aetiology of the erectile dysfunction and was normal in all cases with positive evidence of a psychiatric origin of erectile dysfunction and no clinical indication of a neuronal deficit. Moreover, the sympathetic skin response at the penis was abnormal in three cases with normal results in the other neurophysiological tests. The results emphasize that the local sympathetic skin response at the penis is a useful extension of autonomic testing in ED patients since this method tests local sympathetic pathways and is sometimes the only evidence for autonomic deficit. From a clinical viewpoint, the sympathetic skin response at the penis is a very simple and time-saving neurophysiological method suitable for clinical routine and also for the investigation of outpatients.

Adult↗
PubMed1994

[Rotatory seizures: a rare equivalent of focal epileptic activity. Case report and possible pathophysiology].

We report a typical case of so called "volvular epilepsy" (synonym: retatory seizures, circling epilepsy). Our 59-year-old patient exhibited the characteristic pattern of repetitive walking in small circles, always strictly contralateral to the epileptogenic focus in the right fronto-parietal region. The MRI study indicated a diagnosis of brain tumor in the same area, which was confirmed as an oligodendroglioma. After adequate anticonvulsive treatment there was complete seizure control. Rotatory seizures are rarely reported and usually related to pathological findings in the fronto-temporal region (infarction, neoplasma, giant aneurysm and posttraumatic lesions). Corresponding to the international classification of epileptic seizures, this is a very rare manifestation of a simple partial seizure (without impairment of the conscious state), which can extend to a complex partial seizure (with impairment of consciousness) and secondarily generalized tonic-clonic seizure. In explaining this rare epileptic phenomenon, the controversial concepts (involvement of the striatum, temporal lobe or cortical adverse fields?) are discussed.

Anticonvulsants↗
PubMed1992

Spinal cord infarction: MRI and MEP findings in three cases.

We report findings of magnetic resonance imaging (MRI) in three patients with spinal cord ischemia. While myelography was normal in all three patients, MRI found pathological signal increase on the T2-weighted images in each case. Signal changes in T1-weighted images of hemorrhagic infarction were seen in one patient, and gadolinium-DTPA enhancement because of a disturbed blood-tissue barrier was noted in another. Motor evoked potentials after transcortical magnetic stimulation showed normal latencies with very low amplitudes as a sign of axonal loss in ischemia of the spinal cord.

Aged↗
PubMed1992

Imaging in cerebrovascular disease.

High-resolution structural imaging of ischemic lesions now enables the assignment of complex ischemic clinical symptoms to cortical and subcortical lesions. Functional imaging shows some new features of cerebral ischemia which can be directly investigated in the individual patient. Vascular imaging is rapidly improving with the introduction of magnetic resonance angiography (MRA). Today its diagnostic value is unsettled but promising, in particular if used in combination with other techniques like ultrasonography and positron emission tomography (PET).

Brain Ischemia↗
PubMed1991

Orthostatic changes of cerebral blood flow velocity in patients with autonomic dysfunction.

Simultaneous registrations of intracranial blood flow velocity parameters achieved by transcranial Doppler sonography and basic cardiovascular parameters were carried out during orthostatic changes in normal controls, diabetic patients and patients with pandysautonomia. Normal subjects had a rapid increase in heart rate at a constant blood pressure and a slight decrease in cerebral blood flow velocities associated with a mild increase of the pulsatility index (PI) after being tilted from a horizontal to a vertical position. Diabetics showed a fixed heart rate reflecting the disturbed autonomic innervation but only minor changes of cerebral blood flow velocity, which is similar to normal cerebrovascular autonomic regulation. Patients with pandysautonomia had a fixed heart rate associated with a decrease of systemic blood pressure but a failure of compensatory cerebral autoregulation to maintain normal flow velocity values after standing up. The results suggest that in diabetics cerebrovascular autonomic regulation is intact in contrast to cardiac autonomic function, while in patients with pandysautonomia both functions are disturbed. Criteria for the interpretation of autonomic regulatory mechanisms involved in cerebrovascular flow measurements are discussed.

Adult↗
PubMed1990

[Spectrum analysis of Doppler signals].

Doppler signal spectrum analysis contains useful haemodynamic information. Several parameters of the spectrum can be documented in numerics. Random interaction of the reflectors, the size of the ultrasound sample volume and the procedure of signal analysis influence the results and hence may cause misinterpretation of the data selected. Essential mechanisms influencing the clinician's Doppler-spectrum-analysis are discussed on the basis of a series of 59 angiographically and sonographically examined carotid arteries as well as in the light of theoretical considerations and a review of the literature. Peak frequency linked with a battery of spectrum parameters accuracy are useful to differentiate various degrees of lumen narrowing. Identification or exclusion of minor plaques cannot be achieved with sufficient sensitivity and specificity.

Carotid Arteries↗
PubMed1990

Cerebral blood flow velocity alterations during obstructive sleep apnea syndrome.

We recorded cerebral blood flow velocity (CBFV) for the assessment of CO2-regulated alterations during apnea by means of transcranial Doppler ultrasound in a patient with obstructive sleep apnea syndrome. CBFV increased up to doubled peak flow values during obstructive apneic phases. The results provide evidence for a normal CO2 regulation of CBFV leading to periodic vascular stress during the night.

Blood Flow Velocity↗
PubMed1989

Flow pattern and structural changes at carotid bifurcation in hypertensive cynomolgus monkeys.

Blood flow pattern and morphological changes within the extracranial carotid system were studied in M. fascicularis before, immediately after, and at various intervals (4 hours, 4 days, 10 days, and 4 weeks) after the introduction of systemic hypertension by surgical coarctation of the thoracic aorta. Intra-arterial hemodynamics were assessed by means of both continuous-wave Doppler signal spectrum analysis and multigate pulsed-wave Doppler flow velocity profile processing. Diminished peak frequencies throughout the carotid system and enlargement of the lumen diameter in the common carotid artery and the carotid bulb were major findings and were suspected to be due to cerebral autoregulation at high levels of intracranial vascular resistance. In the internal carotid artery of pure muscular type, the lumen diameter was diminished so the carotid bulb became an area of structural and hemodynamic transition. As a consequence, flow irregularities already observed in this region before surgery considerably increased during hypertension. In addition, endothelial disarray and leucocytic adherence and activation were associated with these hemodynamic alterations within the carotid bulb. Their mutual role in early atherogenesis is discussed.

Animals↗
PubMedDate not supplied

Stroke treatment guided by transcranial Doppler monitoring in a patient unresponsive to standard regimens.

Today secondary prevention of stroke is based on large clinical trials with the disadvantage of a lack of individual pathophysiological aspects. This is mainly due to the difficulty in identifying the source of stroke reliably and rapidly in these patients. Recurrent microembolic events detected by transcranial Doppler monitoring (TCM) has been suggested to individualize treatment. We describe a patient with recurrent ischemic events in the posterior circulation. Repeated TCM of the PCA disclosed microembolic events in the course of an acute embolic lesion pattern demonstrated by MRI. Detection of high-intensity transient signals by TCM provided a useful guidance of pathophysiologically oriented treatment in this patient.

Aged↗
PubMedDate not supplied

Are gait disturbances and white matter degeneration early indicators of vascular dementia?

The objective of this study was to correlate clinical and brain imaging findings with walking inabilities in patients with possible vascular dementia. For 24 patients with suspected initial vascular dementia according to DSM-III-R, structured neurological, neuropsychological and neuroimaging (magnetic resonance tomography) examinations were evaluated alongside computerized gait analysis. All patients revealed an increased variability of gait lines of various degrees: mild (11%), moderate (32%) and severe (57%). Lateralization of gait patterns was present in 68% and bipedal instabilities of posture in 54%. These findings were significantly correlated with frontal periventricular white matter lesions (WMLs), which probably affect the thalamo-cortico-mediocapsular pathways. The association of gait abnormalities with WMLs of the frontocentral subcortical and periventricular territories in patients with possible vascular dementing illnesses may be used as an early indicator of the disease for follow-up and treatment trials. However, since the degree of gait impairment varies considerably relative to the common mild intellectual limitations, these structural lesions are unlikely to be directly related to the dementing process.

Aged↗
PubMedDate not supplied

Failure to identify cerebral infarct mechanisms from topography of vascular territory lesions.

PURPOSE: Our purpose was to determine whether topographic patterns of ischemic damage seen on brain imaging studies are useful for evaluating different mechanisms of infarction and for distinguishing embolic from hemodynamic disorders. METHODS: Early CT scans were reviewed to identify brain infarctions in the middle cerebral artery territory in 800 patients with either significant obstructive lesions of the internal carotid artery (70% stenosis, n = 17; occlusion, n = 85) or nonvalvular atrial fibrillation (n = 186) as the only identified source of stroke. Ninety-nine CT studies were considered suitable for entry into the final analysis. The scans were digitized and superimposed on postmortem brain sections by matching algorithms to display the variability of the cerebrovascular territories. RESULTS: Cortical borderzone-type infarctions were rare and evenly distributed among patients with cardiac sources of embolism (3.2%) and severe carotid obstructions (3.6%). In contrast, subcortical borderzone infarcts occurred significantly more often in patients with carotid obstructive disease (36% versus 16%). However, on computerized segmentation analysis, the topography of infarction was the same in both groups. CONCLUSION: The current concept that stroke mechanisms can be inferred from interpretation of stroke patterns on brain scans is heavily confounded by the variability in intracranial arterial territory distributions. Since individual arterial territories cannot be identified in vivo, interpretation of stroke topography is invalidated. In particular, the cortical wedge-type of borderzone infarction, said to result from hemodynamic compromise in low-flow perfusion territories, is an ambiguous observation and may be seen in patients with cerebral embolism and hemodynamic compromise due to severe carotid disease.

Adult↗