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Biomedical subjects

G Pfeiffer

Publications and source records attributed to G Pfeiffer.

At least 73 records · Page 4Linked to original sources
PubMed1984

Quality control of radiopharmaceuticals.

UNLABELLED: A good quality assurance system ensures that a product will be safe and suitable for the intended use. Quality control is an important part of the quality assurance system. Two main topics are discussed in this paper: General aspects including regulations, possibilities, economics and responsibility; and PROCEDURES: Methods for the determination of the physical, chemical, pharmaceutical and biological purity with special regard to new methods, problems and pitfalls, e.g. the measurement of radioactivity using an isotope calibrator; the radionuclide purity of 123I; alpha- and beta-emitting impurities in 99mTc ; High performance liquid chromatography (HPLC); Mini-chromatograms; and the value of animal tests.

Drug Labeling↗
PubMed1983

Microtubular reaction in human fibroblasts infected by cytomegalovirus. Brief report.

By the use of indirect immunofluorescence it is shown that "early" functions of human cytomegalovirus induce a loss of microtubuli in human foreskin fibroblasts within 12 hours postinfection (p.i.) which persists until about 60 hours p.i. At later times p.i. microtubular structures are eventually reestablished. Following depression during the initial 48 hours p.i. tubulin synthesis in infected cells is significantly enhanced during the initial 48 hours p.i. tubulin synthesis in infected cells is significantly enhanced during the late phase of the infectious cycle suggesting that the mechanisms regulating tubulin synthesis are not impaired.

Cytomegalovirus↗
PubMed1982

Isolation of granulocytes and labelling with indium 111-oxine sulphate.

The isolation of granulocytes from whole blood and labelling with Indium 111-oxine sulphate are described in detail. To isolate the cells a two-step method was used: (1) removal of the red blood cells by methyl cellulose-Ronpacon and (2) separation of the leucocyte-rich plasma with a double gradient (1077, 1097) technique. 111In-oxine sulphate was prepared by adding 111In-chloride to a buffered solution of oxine sulphate. The labelling of the granulocytes with 111In-oxine sulphate was done by incubation at room temperature for 5 min.

Cell Separation↗
PubMed1982

Multicomponent analysis of meat products by infrared spectrophotometry: collaborative study.

A new method for rapid multicomponent analysis of meat products based on infrared transmission was tested in a collaborative study with 4 laboratories. A series consisting of 31 samples of different meats, cooked sausage, liver sausage, and fermented sausage was distributed and analyzed at all laboratories for protein, fat, and water by the present method and by well established reference methods. There was no significant difference between the infrared method and reference methods at the 95% confidence level for determination of protein, fat, and water in meat products.

Animals↗
PubMed1978

Computer angiography: a new tool for x-ray functional diagnostics.

The method of functional imaging is applied to x-ray angiograms. Functional images are generated by inserting at each point of an x-ray image a computed grey or colour value proportional to a dynamic parameter (such as blood velocity) instead of the recorded x-ray absorption value. For this purpose a new system for angiographic image processing has been developed. First results show that the method which we have called Computer Angiography is a tool to extract more information about the blood dynamics in organs in an easier and faster way than with the conventional angiographic technique.

Angiography↗
PubMed1978

[Measurement and differential demonstration of renal blood flow by computer angiography (author's transl)].

A new computer-aided x-ray technique is presented which, unlike conventional cine- or video-densitometry, allows a high-resolution quantitative display of the parameters of renal blood flow as so-called 'functional images'. The parameters include blood flow velocity and local perfusion of the kidney. This technique, which we call computer angiography, has decisive advantages; the functional images provide more, and more rapid, information on renal blood flow dynamics than can be obtained by the qualitative evaluation of a series of pictures. The clinical relevance of computer angiography is illustrated by a nephrotic syndrome, polycystic disease and a hypernephroma.

Adenocarcinoma↗
PubMed1976

Comparison of renal blood flow and transit times measured by means of 99mTc-labelled erythrocytes and Indocyanine Green in humans with normal and diseased kidneys.

1. In nineteen patients with normal or diseased kidneys, renal blood flow, transit times and vascular volume were determined by means of an indicator-dilution method. Two different indicators, plasma-bound Indocyanine Green (IG) and 99mTc-labelled erythrocytes, were used simultaneously. 2. Comparison of the results indicates that IG slightly overestimates renal blood flow, appearance time, mean transit time and vascular volume, as the erythrocyte/IG ratios averaged 0.972, 0.903, 0.93, and 0.921 respectively. Overestimation of the mean transit time was less apparent when it was prolonged. In patients with reduced renal function, the average blood flow values obtained with the two indicators were in good agreement. 3. It is unlikely that axial streaming of erythrocytes accounts for their shorter mean transit time, because the individual erythrocyte/IG mean transit time ratios were independent of the rate of blood flow and the peripheral packed cell volume. 4. Since the erythrocyte/IG mean transit time ratios correlated significantly with the erythrocyte/IG ratios for appearance time and renal blood flow, the common mechanism leading to a depression of all erythrocyte/IG ratios is presumably extravascular circulation and delayed recovery of a small fraction of IG.

Acute Kidney Injury↗
PubMed1976

[Bone-seeking radioactive substances in nuclear medicine].

The concept of bone affinity of a radioactive tracer is developed on theoretical grounds and is discussed on the basis of the various substances used in nuclear medical diagnosis of bone disease. On the basis of results on the uptake of very short lived nuclides and extremely large molecules, evidence is provided that the incorporation of the tracer in the apatite crystal is not a primary criterion of bone affinity since incorporation cannot take place on timelimiting grounds in the former case and on spatial grounds in the latter. The fixation on bone is therefore more likely the result of non-specific adsorption processes. The utility of a radioactive substance in practical application in nuclear medicine depends on the radioactive characteristics of the nuclide and on its behavior in the organism. In this context the quality of the scintigram is particularly dependent on the mode and rate of elimination of that fraction of the tracer that is not bound by the skeleton. The various mechanism which cause differences in the uptake of tracer by healthy and pathological bone tissue are discussed with special regard to the role of blood flow.

Barium↗