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Biomedical subjects

W Steinke

Publications and source records attributed to W Steinke.

At least 55 records · Page 3Linked to original sources
PubMed1992

Thalamic stroke. Presentation and prognosis of infarcts and hemorrhages.

Thalamic strokes in 62 patients selected from the Stroke Data Bank were studied to determine differences among 18 infarctions (INF), 23 localized hemorrhages (ICH), and 21 hematomas with ventricular extension (IVH). Stupor or coma at onset occurred more frequently in the IVH (62%) than in the INF (6%) or ICH (13%) groups and was reflected in significantly lower median Glasgow Coma Scores in the IVH group (7) than in the INF (15) and ICH (14) groups. Although ocular movements were more frequently abnormal in the IVH group compared with the ICH and INF groups, no significant differences were found in the frequency of motor or sensory deficits. Among the 62 strokes, 32 had restricted lesions of the posterolateral (n = 9), anterior (n = 3), paramedian (n = 7), and dorsal (n = 13) portions of the thalamus. Differences in consciousness and in motor, sensory, and oculomotor deficits were found among the topographic subgroups. Stroke-related deaths occurred in 52% of IVH cases, 13% of ICH cases, and no cases of INF. Median lesion volume as detected with computed tomography was greater in hemorrhages (INF, 2 cm3; ICH, 10 cm3; IVH, 16 cm3), with mortality related to increasing hematoma size. Coma, Glasgow Coma Score lower than 9, weakness score greater than 15 of a possible 30, abnormal ocular movements, and fixed pupils were also associated with stroke-related mortality. We conclude that the initial neurologic syndrome does not discriminate infarcts from intrathalamic hemorrhages. Ventricular extension, however, causes significantly more severe deficits and higher mortality.

Cerebral Hemorrhage↗
PubMed1992

Paramedian thalamopeduncular infarction: clinical syndromes and magnetic resonance imaging.

We prospectively examined 11 patients with magnetic resonance imaging-documented infarction in the paramedian thalamopeduncular region, which is supplied by the superior mesencephalic and posterior thalamosubthalamic arteries. Variations in the size and rostral-caudal extent of infarction correlated with the following three clinical patterns: (1) With unilateral paramedian mesencephalic infarction, an ipsilateral third nerve paresis was accompanied by mild contralateral hemiparesis or hemiataxia. Contralateral ptosis and impaired upgaze were observed in two patients; one of them showed additional damage to the posterior commissure. (2) With bilateral infarction in the thalamopeduncular junction, involving the mesencephalic reticular formation, supranuclear vertical gaze defects were accompanied by impaired consciousness or memory, and mild aphasia in some patients. Persistent amnesia was observed only when the dominant anterior nucleus or mamillothalamic tract was damaged. (3) With larger thalamopeduncular infarcts, partial or complete third nerve paresis was combined with supranuclear gaze disturbance and delayed contralateral tremor. An unusual gaze disorder, a variant of the vertical "one-and-a-half syndrome," occurred with a small strategically placed lesion at the thalamopeduncular junction, best explained by selective damage to supranuclear pathways or partial nuclear involvement. The primary cause of these infarctions was embolism to the basilar apex or local atheroma at the origin of the posterior cerebral artery.

Adult↗
PubMed1992

Comparison of flow disturbances in small carotid atheroma using a multi-gate pulsed Doppler system and Doppler color flow imaging.

The capacity of a multi-gate pulsed Doppler (MPD) system and Doppler color flow imaging (DCFI) for the evaluation of flow patterns was studied in 14 patients with 17 nonstenotic carotid plaques (luminal narrowing less than 40%). Plaque morphology was assessed by means of a high-resolution B-mode system with subsequent three-dimensional reconstruction of the lesion surface. MPD velocity profiles obtained proximally, centrally and distally to the plaque (51 analyses) were normal in 31 sites corresponding to 28 undisturbed and 3 turbulent flow patterns assessed by Doppler color flow imaging (90% specificity). Of the 10 irregular MPD flow profiles, DCFI detected turbulence in 7 (70% sensitivity). 10 asymmetric MPD waveforms without irregularities were normal in 7 and turbulent in 3 DCFI studies. These results suggest, that MPD is superior to DCFI for the detection of nonturbulent flow asymmetry nearby small carotid plaques. However, DCFI displays turbulence with a high specificity and reasonable sensitivity and visualizes the morphologic-hemodynamic interaction in carotid atherosclerosis simultaneously.

Aged↗
PubMed1992

Spontaneous vertebral artery dissection initially mimicking myocardial infarction.

BACKGROUND AND PURPOSE: Vertebral and carotid artery dissections may present with very different signs and symptoms, making early recognition difficult. However, diagnosis should be established as soon as possible to prevent unnecessary diagnostic investigations and to institute adequate treatment. CASE DESCRIPTION: A 46-year-old man presented with severe intermittent pain of his left upper arm and general discomfort. During extensive cardiological evaluation for suspected myocardial infarction, a severe brain stem syndrome occurred. Ultrasound Doppler studies detected vertebral artery dissection, which was confirmed by angiography. CONCLUSIONS: The unusual initial presentation of vertebral artery dissection delayed an early diagnosis and adequate treatment. Because noninvasive methods are available today, their applications are recommended in similarly uncharacteristic circumstances.

Aortic Dissection↗
PubMed1992

Caudate hemorrhage with moyamoya-like vasculopathy from atherosclerotic disease.

BACKGROUND AND PURPOSE: Caudate hemorrhage usually results from hypertension, rupture of arteriovenous malformation or aneurysm, or rarely, moyamoya disease. Moyamoya-like changes related to severe atherosclerotic occlusive disease, usually causing ischemic stroke, have been reported. CASE DESCRIPTION: A 51-year-old normotensive patient was admitted with headache due to a left caudate hematoma with ventricular extension. There was a history of smoking, leg claudication, elevated cholesterol, and coronary artery disease. Angiography demonstrated complete extracranial carotid occlusion on the left and atherosclerotic stenosis at the bifurcation on the right, with supraophthalmic occlusion distally. At the base of the brain, bilateral moyamoya-like vessels, presumed to be secondary to atherosclerotic occlusion, were evident, but neither aneurysm nor arteriovenous malformation was present. Cerebral blood flow and transcranial Doppler studies indicated severely impaired cerebral perfusion that improved after bilateral extracranial-to-intracranial bypass surgery. CONCLUSIONS: Atherosclerotic occlusive carotid disease with moyamoya-like changes may be a rare cause of caudate hemorrhage. A decrease in moyamoya vessels with bypass surgery may reduce the risk of recurrent hemorrhage.

Carotid Arteries↗
PubMed1992

Symptomatic and asymptomatic high-grade carotid stenoses in Doppler color-flow imaging.

We examined 63 patients with 31 symptomatic and 44 asymptomatic carotid stenoses with Doppler color-flow imaging (DCFI); conventional Doppler duplex had shown a hemodynamic obstruction (greater than or equal to 80% stenosis) in all patients. Analysis of plaque surface morphology demonstrated more ulcerated plaques in symptomatic (43%) than asymptomatic (23%) stenoses. Although the frequency of homogeneous and heterogeneous plaques was not different, calcific lesions were more frequent in asymptomatic (46% versus 29%), and echolucent plaques, probably indicating mural thrombi, were more frequent in symptomatic (29% versus 11%) stenosis. Color-coded hemodynamic patterns, such as jet flow, poststenotic turbulence, or reversed flow, were not different in symptomatic and asymptomatic stenoses. Comparison of DCFI with 30 angiograms showed agreement in plaque surface analysis in 70%. DCFI measurements of area reduction in cross sections correlated with angiography in 85%, while DCFI tended to underestimate the degree of stenosis from diameter reduction in longitudinal cuts. The advanced DCFI technique identified distinct morphologic features but no hemodynamic patterns, separating symptomatic from asymptomatic high-grade carotid stenoses.

Carotid Arteries↗
PubMed1991

125I-endothelin-1 and 125I-big endothelin-1 in rat tissues: autoradiographic localization and receptor binding.

The potent vasoconstrictor peptide, endothelin-1 (ET-1), which exhibits a characteristically long-acting activity in vitro and in vivo, is thought to be generated in endothelial cells from a less active intermediate, big endothelin-1 (big ET-1). In addition to ET-1, big ET-1 is also present in the circulation. The autoradiographic localization of 125I-big ET-1 and 125I-ET-1 has been studied after intravenous administration in rat tissues. Highest enrichment of radioactivity was found in the kidney cortex for both peptides. Compared to blood levels, enrichment of radioactivity is also detected, in the vascular wall of the aorta. Comparing the radioactivity pattern of ET-1 and big ET-1, a nearly identical tissue distribution is observed, with the exception of the relative enrichment in the lung and the zona glomerulosa after administration of ET-1. Both radioligands show a specific and saturable binding to lung and kidney membranes. In the case of lung tissue, Ki values are 10(-10) M for endothelin-1 and 10(-8) M for big endothelin-1. This difference in affinities may account for the lack of binding of big endothelin-1 to lung tissue.

Animals↗
PubMed1991

Autoradiographic localization of [125I]-C-ANP compared to [125I]-ANP in rat tissue.

Whole-body autoradiography demonstrated the different distribution of [125I]-C-ANP and [125I]-ANP to rat tissues. Highest enrichment of radioactivity of both labelled peptides was found in the kidney. In some organs we found remarkable differences between [125I]-ANP and [125I]-C-ANP. In the kidney cortex, especially in the glomeruli, as well as in the endocardium, the zona glomerulosa and the medulla of the adrenal gland, where high levels of radioactivity after [125I]-ANP administration were detected, no or just few radioactivity was found after administration of [125I]-C-ANP. On the other hand in the kidney papilla and the outer subcortical medulla, characteristic blackening was found after [125I]-C-ANP administration. Those differences might be important for the understanding of pharmacological actions of ANP analogues.

Adrenal Glands↗
PubMed1991

Doppler colour flow imaging after carotid endarterectomy.

Sixty-six patients (72 carotid arteries) were examined after carotid endarterectomy (CEA) using Doppler colour flow imaging (DCFI). Examinations were performed 4-18 days (mean: 7 days) after surgery (32 patients, 34 arteries) or between 2 and 100 months (mean: 39 months) after CEA (34 patients, 38 arteries). Minor vessel wall abnormalities were found in 36% in the internal carotid artery (ICA) and in 55% in the common carotid artery (CCA) or bifurcation. One patient had a minor residual ICA stenosis after surgery; two low-grade stenoses and three ICA-occlusions were diagnosed at follow-up. Altered flow patterns occurred most in CCA (90%) and were predominantly located adjacent to the vessel wall and in dilated vascular segments of the CCA. Disturbed haemodynamics in the ICA were less marked (57%) and frequently found in the central vessel lumen or diffusely distributed. We conclude that surgically induced changes of the vessel geometry and residual or recurrent vascular wall abnormalities are often associated with distinct haemodynamic disturbances, which can reliably be detected by DCFI.

Blood Flow Velocity↗
PubMed1991

The anterior choroidal artery does not supply the corona radiata and lateral ventricular wall.

BACKGROUND AND PURPOSE: We sought first to characterize the clinical syndromes of patients found to have angiographic, computed tomographic, or magnetic resonance imaging scan indexes of anterior choroidal artery territory infarction and then to determine the frequency of involvement of the periventricular corona radiata in such patients. METHODS: Sixteen patients were selected based on angiographically, or surgically, documented occlusion of the anterior choroidal artery or based on infarcts whose minimal lesions included the anterior choroidal territory as defined by Kolisko and Beevor. We mapped the lesions using the templates of the Matsui and Hirano atlas and entered them into a computer using a program allowing overlapping diagrams of the cases. RESULTS: The anatomic distributions were fairly uniform, all involving the lower portion of the posterior limb of the internal capsule, the medial pallidum (75% of cases), cerebral peduncle in 44%, thalamus in 37%, and the medial temporal lobe in 38%. None extended outside these areas to include the upper corona radiata. The clinical picture corresponded to the well-established neurological syndrome featuring motor deficits with varying degrees of visual field and sensory impairments. Only two showed hypesthetic ataxic hemiparesis. CONCLUSIONS: Our findings indicate that the syndrome of anterior choroidal artery infarction is fairly uniform; ataxic hemiparesis occurs infrequently; and lesions in the lateral ventricular wall and the corona radiata are not part of the territory supplied by the anterior choroidal artery.

Adult↗
PubMed1991

[The value of duplex sonography in cerebral ischemia].

Doppler color flow imaging (DCFI) is a new ultrasound technique for the assessment of extracranial arterial disease. This system is a further development of conventional duplex systems. The new technique provides a real-time gray-scale echotomogram (B-mode) and simultaneously superimposed color-coded Doppler signals of intravascular blood flow. The advantages of the DCFI are improved identification of vascular structures, faster data acquisition, shorter examination time, better characterization of the surface, structure and extent of plaques with easier detection of ulcerative lesions or thrombotic material. Due to these advantages, the sensitivity for the detection of lesions which may cause arterio-arterial embolisms to the brain, is increased. With DCFI, it is possible to visualize the extracranial portion of the vertebral arteries. This improves the evaluation of the vertebro-basilar circulation. DCFI is a safe and fast method in the follow-up procedure of symptomatic and asymptomatic patients and after carotid endarterectomy. Using DCFI, the interaction between morphology and hemodynamics in the extracranial vessels can be analyzed, which is important particularly for the understanding of the potential risk of different plaque types.

Aortic Dissection↗
PubMed1991

Autoradiographic localization of 125I-big endothelin-1 in rat tissues.

Endothelin-1 (ET-1), a potent vasoconstrictor with a characteristically long-acting activity in vitro and in vivo, is thought to be generated in endothelial cells from a less active intermediate, big endothelin-1 (big ET-1). In addition to ET-1, big ET-1 is also present in the circulation. The autoradiographic localization of 125I-big ET-1 has been studied after intravenous administration in rat tissues. Highest enrichment of radioactivity was found in the kidney cortex. Compared to blood levels, enrichment of radioactivity is also detected, especially in the vascular wall of the aorta. Comparing the radioactivity pattern of ET-1 and big ET-1, a nearly identical tissue distribution is observed, with the exception of the relative enrichment in the lung, the endocardium and the zona glomerulosa.

Animals↗
PubMed1990

Doppler color flow imaging of common carotid artery dissection.

Sonographic findings are reported in a case of common carotid artery dissection assessed by Doppler color flow imaging and confirmed by angiography. Advantages and clinical relevance of this new ultrasound method for this diagnosis are discussed.

Aortic Dissection↗
PubMed1990

Variability of flow patterns in the normal carotid bifurcation.

One hundred and nine carotid bifurcations of 56 healthy subjects were examined by means of a Doppler color flow imaging (DCFI) system. Flow separation was found in 102 (93.6%) bifurcations. Different patterns of the spatial and temporal distribution of flow separation zones could be distinguished: separated flow was either restricted to the proximal external (5.9%), the internal (34.3%) or both carotid arteries (40.2%). In 11.8% zones of secondary flow extended from the internal into the external carotid artery around the flow divider, and in 7.8% the distribution was diffuse. The maximum of reversed flow signals occurred immediately after the systolic peak (73%) but lasted for highly variable intervals throughout the cardiac cycle. This demonstration of the unexpectedly various spatial and temporal patterns of secondary flow phenomena contrasts with concepts from in vitro flow studies. This information about conditions in vivo must be considered in investigations of early atherosclerosis in the human carotid bifurcation.

Adolescent↗
PubMed1990

Carotid artery disease assessed by color Doppler flow imaging: correlation with standard Doppler sonography and angiography.

Carotid artery disease was assessed in 180 patients by means of color Doppler flow imaging. Color Doppler findings in 360 carotid arteries were compared with the results of standard Doppler sonography, and color Doppler findings in 60 bifurcations were compared with the results of intraarterial angiography. The sensitivity of color Doppler for the detection of carotid disease was 100% when compared with angiography. The accuracy of color Doppler in classifying minor (40-60%), moderate (61-80%), and severe (81-90%) stenosis ranged from 91.3% to 97.8% vs standard Doppler sonography, and from 91.7% to 95.8% vs angiography. Whereas all occlusions were identified correctly by both color Doppler and angiography, four pseudoocclusions of the carotid artery were misdiagnosed as occluded. Characteristic features providing reliable criteria of the degree of stenosis are (1) intensity, extent, and duration of color fading; (2) postprocessed systolic peak frequency; (3) plaque extent on serial sonograms; and (4) poststenotic flow patterns. Display of hemodynamic disturbances induced by less pronounced plaques showed highly variable patterns that could not be anticipated from the plaque morphology alone. Thus, color Doppler preserves the advantages of standard Doppler and duplex sonography but provides additional information about otherwise anechoic necrotic and thrombotic material that often causes cerebral embolisms. With atherogenesis, repair mechanisms may be sustained or progression be stopped by reducing the risk factors and instituting medical treatment; thus, the application of this noninvasive technique is important.

Adult↗
PubMed1989

[Diagnosis and progress of carotid artery dissecting aneurysm].

33 patients with angiographically confirmed dissection of the internal carotid artery (ICA) were followed prospectively. Cardinal symptoms were: 1) focal disturbances of the cerebral circulation (n = 28); 2) unilateral headache or neck pain (n = 20); 3) incomplete Horner's syndrome (n = 9). Neurological deficits without pain or sympathetic nerve damage developed in 11 patients. All patients had abnormal Doppler ultrasound findings over the ICA; in 22 there were markedly reduced flow velocities and retrograde flow components ("to- and- fro" phenomenon), typical of carotid artery dissection. During a mean observation time of 6.9 +/- 5.7 months serial Doppler ultrasound and angiographic examinations demonstrated recanalization in 73% after an average of 56 days. Angiographically different types (long segments in 13; pseudo-occlusions in 7; pseudoaneurysms in 5; and distal stenoses in 6; others in 2) are interpreted as expressions of different stages in the development of dissection up to complete recanalization.

Adolescent↗
PubMed1989

[Rhodococcus equi infection in HIV disease].

A case of Rhodococcus equi pneumonia associated with septicemia and metastatic brain abscess in an HIV-infected male is presented. Clinical findings and the diagnostic and therapeutic approach are discussed. Cavitating pulmonary disease was rapidly improved by six-week combined oral and parenteral antibiotic treatment. However, pulmonary relapse and brain abscess were documented after one month. Therapy with ceftriaxone, ciprofloxacin and cotrimoxazole on an outpatient basis again led to clinical and radiological improvement after four weeks. Surgical resection of localized processes should be considered early, and prolonged antibiotic therapy over months is recommended.

Acquired Immunodeficiency Syndrome↗