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Biomedical subjects

F Meyer

Publications and source records attributed to F Meyer.

At least 235 records · Page 13Linked to original sources
PubMed1983

LEYTAS analysis of cytological specimens: the results of thousand cervical smears.

This paper describes the application of a television-based system (LEYTAS) in machine analysis of cervical specimens. LEYTAS basically consists of a Leitz microscope, the texture analysis system (TAS, Leitz), a TV camera, a 4-bit grey value memory and a minicomputer (PDP 11/23). A series of 1176 Feulgen stained cervical smears has been analysed in an automated procedure using image transformation for cell selection and artefact rejection. During the analysis of the entire series new artefact rejection procedures have been added to the automated analysis. This addition decreased the percentage of false positives to 15% in the last 277 analysed smears. This percentage concerns machine performance alone. A rapid visual interaction procedure decreases this percentage to 9%. Out of 210 morphologically positive smears (diagnosis Papanicolaou class 3b or more) from the total series, one smear was missed by LEYTAS using the machine classification.

Automation↗
PubMed1983

Image analysis: a consumer's guide.

The last years have seen an explosion of systems in image analysis. It is hard for the pathologist or the cytologist to make the right choice of equipment. All machines are stupid, and the only valuable thing is the human work put into it. So make your benefit of the work other people have done for you. Chose a method largely used on many systems and which has proved fertile in many domains and not only for your specific to day's application: Mathematical Morphology, to which are to be added the linear convolutions present on all machines is a strong candidate for becoming such a method. The paper illustrates a working day of an ideal system: research and diagnostic directed work during the working hours, automatic screening of cervical (or other) smears during night.

Animals↗
PubMed1981

Blood trauma during extracorporeal circulation: a comparison between two bubble and two membrane oxygenators in a standardized dog model.

Determination of blood traumatization by extracorporeal circulation systems (ECC) in clinical trials may be interfered with by the underlying heart disease, by priming the circuit with blood or plasma expanders and by different operation techniques requiring a variable amount of coronary suction. Therefore, in this study a standardized animal model was used to compare blood traumatization in 2 bubble and 2 membrane oxygenators. After 2 hours of extracorporeal circulation, there was no advantage of the membrane over the bubble oxygenators concerning hemolysis, platelet preservation and induction of clotting factors. Red cells and platelets were traumatized in membrane oxygenators during the first 30 minutes without a significant further increase, whereas blood trauma in bubble oxygenators increased until bypass was disconnected. Therefore bubble oxygenators appear better suited for shorter perfusions, whereas membrane oxygenators are the superior choice in perfusions lasting longer than 2 hours.

Animals↗
PubMed1981

The release of pancreatic polypeptide by exogenous CCK in man and dog.

4 healthy volunteers received commercial 20% pure CCK-33 in 4 consecutive doses of 0.5, 1.0, 2.0, 4.0 IDU/kg/h. blood samples were assayed for pancreatic polypeptide (PP) by radioimmunoassay. Plasma PP concentrations increased stepwise from a basal level of 67 +/- 15 pmol/l to a maximum of 198 +/- 46 pmol/l (p less than 0.05). In 4 mongrel dogs with Thomas cannulas, the same doses of 99% pure CCK-33 were successively infused. Plasma PP concentrations rose stepwise with each dose from 44 +/- 7 to 259 +/- 43 pmol/l (p less than 0.02). This rise significantly correlated with pancreatic protein secretion (p less than 0.01). It is concluded that intravenous CCK-33 induces the release of PP in man and in dog, in a dose-dependent manner.

Animals↗
PubMed1981

Growth inhibition of Staphylococcus aureus after experimental infection of the udder by high and low concentration of lactoferrin and lysozyme in milk.

Ten Holstein-Friesian cows were distributed according to their lactoferrin and lysozyme concentrations in milk into groups with high and low concentrations. In each cow, a front and a rear mammary quarter was infected by inoculation of 10(8) colony forming units of Staphylococcus aureus while the other two quarters were infused with 2 ml of sterile milk. The reaction was observed during the following nine days. After 10 hours the cell count, the lactoferrin and lysozyme concentrations were increased in the infected and control quarters. In milk samples with a high initial lactoferrin concentration the colony forming units of S. aureus were higher than in those with a low concentration. In milk samples with a high lysozyme concentration with colony forming units of S. Aureus were significantly lower than in those with low concentrations. These results show, that the lysozyme concentration in milk of healthy udders could indicate the preparedness for defense against infectious diseases.

Animals↗
PubMed1980

[Chemical structure and biological activity of cholecystokizin octapeptides with respect to the stomach and pancreas].

Dose response curves of the octapeptide of cholecystokinin (CCK-8) and 3 of its methoxinine analogues have been established in 4 conscious dogs with respect to gastric and pancreatic secretion. In the analogues the methionine was replaced by methoxinine in position 3 (B) and (D) or 6 (C). Of the 4 tested substances CCK-8 exhibited most activity with regard to pancreatic protein secretion, followed by B, C, and D. Analogue C had the strongest stimulating effect on gastric acid secretion, while its effect on pancreatic secretion was minor. Correlation of chemical structure with biological activity points to the importance of the methionine residue in position 6.

Animals↗
PubMed1980

Net albumin transport across the wall of the rabbit common carotid artery perfused in situ.

We have studied the transport of radioactively labelled albumin in the rabbit common carotid artery perfused in situ at 100 cm H2O luminal pressure in the anaesthetized living animal, assessing the distribution of concentration across the wall by means of sequential frozen sectioning. We have compared the findings with those of experiments in which we have attempted to saturate the wall with label. Our findings support the belief that there is a net transport of macromolecules across the arterial wall. They show in addition that the wall is inhomogeneous. The distribution volume for label is greater in the adventitia than the media, which appears to offer a larger resistance. The transport process is seemingly dominantly diffusional.

Animals↗
PubMed1980

Automated analysis of cervical specimens using the T.A.S.

The Leyden Television Analysis System (LEYTAS) is applied to the automated analysis of five positive specimens (2 cases of severe dysplasia, 2 cases of carcinoma in situ and 1 case of invasive carcinoma) and five negative specimens (4 cases of inflammation and 1 normal specimen). Two detection criteria based on size and contrast (so called 'top hat' transformation) are used to detect suspect nuclei. Thresholds and sizes have been used at two levels: 'high level' to detect very large and/or dark nuclei, and 'low level' to detect nuclei, of which absorption and/or size is only slightly increased compared to the nuclei of normal epithelial cells. In all positive specimens analysed with the 'high level' program suspect nuclei are automatically detected, whereas no nuclei are detected in any of the negative specimens. Using the 'low level' program many more suspect nuclei are detected in the positive specimens (up to a number of 294). This program results in some detected nuclei in the negative specimens, but the number remains relatively low (not more than 3 in the investigated cases).

Autoanalysis↗
PubMed1980

Quantitative analysis of the chromatin of lymphocytes: an assay on comparative structuralism.

With 26 letters we can form all the words we use, and with a few words it is possible to form an infinite number of different meaningful sentences. In our case, the letters will be a few simple neighborhood image transformations and area measurements. The paper shows how, by iterating these transformations, it is possible to obtain a good quantitative description of the nuclear structure of Feulgen-stained lymphocytes (CLL and normal). The fact that we restricted ourselves to a small number of image transformations made it possible to construct an image analysis system (TAS) able to do these transformations very quickly. We will see, successively, how to segment the nucleus itself, the chromatin, and the interchromatinic channels, how openings and closings lead to size and spatial distribution curves, and how skeletons may be used for measuring the lengths of interchromatinic channels.

Cell Nucleus↗
PubMed1980

[The effect of sulfur compounds (N-acetylhomocysteine-thiolactone and penicillamine) on liver collagen metabolism in chronic thioacetamide poisoning].

The influence of N-acetyl-homocysteine-thiolactone (AHCT) and penicillamine on experimental thioacetamide (TAA)-induced liver fibrosis was investigated. TAA causes an increase in liver collagen content, which can partly be prevented by penicillamine and AHCT. This prevention is most effective, when the TAA-intoxication started earlier than the therapy with these two substances. The therapeutic effect of penicillamine is achieved by an inhibition of collagen biosynthesis and cross-linking (with an increase in the easily soluble collagen fractions). In the case of AHCT the inhibition of pathological collagen synthesis in experimental liver fibrosis cannot be explained by disturbed collagen cross-linking or increased collagen solubility. Whether collagen synthesis is inhibited and/or other influences of AHCT are present has still to be analyzed.

Acetamides↗