Showing papers by "Ulrich Bogdahn published in 1990"

Transcranial color-coded real-time sonography in adults.

Abstract: We investigated the diagnostic potential of transcranial color-coded real-time sonography in 52 individuals using a phased-array ultrasound system with color-coded blood flow representation. Ultrasound scans in the axial and coronal planes were feasible through temporal acoustic bone windows in 49 subjects, enabling depiction of the main parenchymal and vascular structures as well as the ventricular system. Color-coded representation of blood flow in the cerebral vessels allowed unequivocal identification of the circle of Willis within the anatomic black-and-white B-mode image of the parenchymal structures. In Doppler mode, vascular blood flow phenomena may be analyzed semiquantitatively using the Doppler frequency spectrum. This noninvasive, serially applicable, mobile beside method may complement conventional neuroradiologic imaging methods, allowing on-line studies of functional processes within the adult brain.

Imaging of cerebral arterio-venous malformations by transcranial colour-coded real-time sonography

Abstract: Transcranial color-coded real-time sonography (TCCS) is a new diagnostic method allowing the non-invasive imaging of parenchymal and vascular structures of the adult brain through the intact skull. A description of the sonographic findings in two patients presenting with a radiologically ascertained arterio-venous malformation is provided. The AVM's can be depicted in the two-dimensional B-mode image as echodense areas interspersed with zones of lower echodensity. Their extension correlated with corresponding MRI images. The color-coded illustration of intravascular flow phenomena allowed the distinct identification of the major afferent feeding vessels, the venous drainage and of the vascular convolution of both AVM's. Information on hemodynamics, as e.g. the blood supply of the angioma by the contralateral internal carotid artery, are obtained by color-coded identification of intravascular flow direction including analysis of the Doppler frequency spectrrum. All findings obtained by TCCS complied with those established by angiography. We conclude, that TCCS is a suitable method for early diagnosis and long term follow up of cerebral AVM's.

Melanoma-inhibiting activity inhibits cell proliferation by prolongation of the S-phase and arrest of cells in the G2 compartment.

Abstract: Autocrine-secreted melanoma tumor growth-inhibiting activity (MIA, approximately Mr 8000) was isolated from supernatants of a malignant melanoma cell line HTZ-19 dM, established from a central nervous system-melanoma metastasis. Cell cycle kinetic analysis performed with bromodeoxyuridine/Hoechst flow cytometry revealed a MIA-sensitive period at the G0/G1 to S traverse; MIA mediated prolongation of the S-phase and increased arrest of cells in the G2 compartment. Growth inhibition by MIA is cell-density dependent; maximal effect is seen at low densities, and the effect may be partially antagonized by whole serum. MIA may cause growth stimulation at high cell densities and low MIA concentrations. The effect of MIA on different histological neuroectodermal cell types was compared by the same methodology: proliferation of a second malignant melanoma was inhibited, and no effect was observed with an ependymoma; 2 glioblastomas were slightly stimulated. Effects on human fibroblast-like cell strains were inconsistent. The mechanism of MIA is discussed in relation to other endogenous autocrine growth inhibitors.

Die transcranielle farbcodierte real-time Sonographie des Erwachsenen: Ein neues diagnostisches Verfahren

Abstract: Die transcranielle farbcodierte real-time Sonographie (TCCS) ist eine neue nichtinvasive und mobil einsetzbare diagnostische Methode, die die zweidimensionale Real-Time Abbildung cerebraler parenchymatoser und vaskularer Strukturen erlaubt. Wir untersuchten 215 Probanden uber 18 Jahre durch die geschlossene Schadeldecke (53 Gesunde, 162 cerebral Erkrankte). Verwendet wurde ein Ultraschallsystem mit farbcodierter Wiedergabe intravasalen Blutflusphanomene, ausgestattet mit einer 2, 25 MHz Sonde. Akustische Knochenfenster fanden sich beim Erwachsenen in einer Zone, die von der linea temporalis inferior und dem processus zygomaticus begrenzt werden. Die TCCS erlaubt, weite Teile des basalen Gefaskranzes zweidimensional darzustellen. Eine genaue Analyse des intravasalen Blutflusses ist mit dem integrierten pW-Doppler moghch. Die Abgrenzung des venosen Systems gelingt noch nicht, da die Flusgeschwindigkeit die Nachweisgrenze von 30 cm/sec. nicht uberschreitet. Telencephale, diencephale, mesencephale und pontine parenchymatose Hirnareale sind mit der TCCS zweidimensional abbildbar, wobei verschiedene Gewebe unterschiedliche Echogenitat aufweisen. Blutungen und Hirntumoren sind in einem hohen Prozentsatz ebenso abzugrenzen wie cerebrale Gefasstenosen, Insulte, AV-Angiome und Aneurysmen. Auch Komplikationen neurologischer Erkrankungen wie Hydrocephalus, Hirnodem und Vasospasmus sind mit dieser Methode identifizierbar. Als Echzeitverfahren erlaubt die TCCS Einblick in die Dynamik cerebraler Prozesse.