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Biomedical subjects

A Findling

Publications and source records attributed to A Findling.

6 recordsLinked to original sources
PubMed1997

An open distributed medical image and signal data server network with World Wide Web front-end.

In modern patient care and medical research diagnostic imaging from multiple modalities plays an essential role. In general these digital image data are acquired at different locations. An efficient access to the data via network is often not provided due to technical, organisational and political reasons. This article presents an approach to solve the problem by means of an open distributed data server network with Web-based front-ends and describes the prototype DACHS that has been developed at the University Hospital of the Technical University of Munich.

Computer Communication Networks↗
PubMed1994

Computerised image analysis in conjunction with fluorescence microscopy for the study of blood-brain barrier permeability in vivo.

The present paper describes a new method using computerised image analysis techniques for quantification of tracer extravasation over the blood-brain barrier as studied by intravital fluorescence microscopy. Cats were equipped with an open cranial window and continuously infused with fluorescein isothiocyanate-labelled dextran (FITC-dextran, mol. wt. 70,000) to maintain a steady plasma concentration. Several cortical fields were recorded in each experiment and the images stored on video tape for off-line analysis. This procedure, which largely eliminates the superficial pial vasculature and allows extraction of the extravasation areas, consists of the following steps: (1) averaging of images, (2) software shading correction based on the original images for compensation of optical non-uniformity, (3) correction of displacement artefacts, (4) intensity adjustment, (5) generation of subtraction images by subtracting the first image of a series from the subsequent ones, (6) median filtering and thresholding, (7) a length recognition algorithm, and (8) elimination of small areas. Compared to the previously described method, step (2) has been newly developed and steps (4) and (8) added to enhance sensitivity for detecting tracer extravasation. The degree of extravasation in a cortical field at a given time point [E(f) value] was calculated as the mean intensity of the remaining pixels. The E(f) is a quantitative value computed by a fully automatised procedure which takes into account the number, as well as the size and intensity, of extravasation areas in a given cortical field. The E(f) values obtained at different times in a series of experiments were averaged to give the E(I) value.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1994

Investigation of blood-brain barrier permeability by means of computerized image analysis.

Intravital fluorescence microscopy has been widely used to study changes of blood-brain barrier (BBB) permeability in vivo. However, quantification of tracer extravasation by counting leaky spots provides only a rough estimate of permeability increase. We have therefore developed a new method for measurement of tracer extravasation from cerebral blood vessels by combining image analysis techniques with intravital fluorescence microscopy. This method is based on generation of subtraction images after shading and displacement correction. Subtraction images are further processed to eliminate noise and diminish artefacts due to vessel distortion and/or dilatation. The "degree of extravasation" (E(f) value) which is then calculated takes into account the number and size of leaky spots as well as their intensities. Examples are shown to illustrate that pure vasodilatation does not increase E(f) as long as the BBB-permeability is not disturbed. This newly developed method may prove helpful for comparison of tracer extravasation under different experimental conditions.

Animals↗
PubMed1979

Tremor and somatosensory studies during chamber He-O2 compressions to 13.1, 25.2, 37.3, and 49.4 ATA.

Comparison was made between intentional and postural tremor amplitudes with a 2-to 50-Hz bandwidth in four men rapidly compressed from surface to 13.1, 25.2, and 37.3 ATA in 4 h while breathing helium-oxygen mixtures (Predictive Studies IV, University of Pennsylvania). Excursions with compression rates of 20 and 40 ft/min were then made to 49.4 ATA on exposure days 2 and 3, returning to saturation at 37.3 ATA for 6 additional days. During compression from 25.2 to 37.3 ATA, there were increases in tremor amplitudes for both intentional and postural tremor in the 3-to 7-Hz and 8- to 12-Hz ranges. Both types of tremor showed increases in amplitudes at 49.4 ATA on exposure days 2 and 3. Amplitude changes in postural tremor, which occurred only on the fastest compression to 49.4 ATA, were less evident than those in intentional tremor during the remaining dive profile, and adaptation to pressure exposure could be defined by day 8. Intentional tremors did not show adaptation at pressure.

Adult↗