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Biomedical subjects

G Wassilew

Publications and source records attributed to G Wassilew.

28 records · Page 2Linked to original sources
PubMed1980

[Multivariable EDV-program for light and electron microscopic morphometry].

A computer program for morphometry and stereology in which conventional morphometric and stereological data acquisition (direct linear measurement, point counting technique) is used and which is designed for variable application of conventional and electron microscopy is presented. There are several program variants and magnification stages each designed for a different structural level. There is fixed number of essential subcellular, cellular and extracellular structures for different kinds of tissue (myocardial, liver and connective tissue), but this number can be enlarged with each stage of magnification and for each measured parameter by reserving free places for evaluating additional structures. Thanks to the extended program and to the fact that these free places are interchangeable, the program can be used independently of the kind of tissue examined and of the kind of morphological information sought. The program structure is realized by means of a master control and 4 external subprograms. The statistical analysis of the morphometric stereological parameters is calculated by image, case by case or group by group. The mean values of the calculated primary and secondary parameters, the standard errors and the standard error/mean value ratio are printed out. All common stereological parameters and the essential cellular and extracellular structures of different kinds of tissue are described in quantitative terms with the aid of the program.

Computers↗
PubMed1980

[Methods for the determination of the surface density of myocardial cell membranes with special regard to the mitochondrial cristae].

The possibility of using modified formulas for determining the surface density of cellular membranes of the heart muscle cell was discussed, sarcoplasmic reticulum and particularly mitochondrial cristae being used as examples. By using modified formulas and different stages of magnification it could be possible to determine the surface density of critae also in such experimental conditions in which the mitochondrial cristae appear to be densely packed.

Animals↗
PubMed1980

[Structure and function of the myocardial cell in various forms of adaptation].

Comparative ultrastructural morphometric and physiological examinations of the rat's myocardium after swimming exercise, hypokinesia and hypobaric hypoxia show concurrence between morphometric and contractility parameters. Differences in the changes of cell organelles in general and of mitochondria and sarcoplasmic reticulum in particular observed in the experimental models of adaptation used provide a basis for making inferences as to different structural reaction patterns of the myocardial cell. Special importance is attached from the functional point of view to changes in the volume and membrane surface density of the longitudinal sarcoplasmic reticulum and in Golgi's apparatus. Different structural reaction patterns suggest different adaptation mechanisms of the myocardial cell.

Adaptation, Physiological↗
PubMedDate not supplied

Qualitative and quantitative changes in the ultrastructure of the dog heart after temporary ischaemia and coronary reperfusion.

A total ischaemia of one area of the myocardium was produced by ligature of a coronary artery in dogs. After 30 min, 1 hr, 2 hrs, and 4 hrs the ligature was loosened and the artery was for 1--2 hrs reperfused up to 4--7 days. At the end of the ischaemia and after reperfusion the ultrastructure of the myocardium was qualitatively and morphometrically investigated. The findings concerned: loss of glycogen (partly glycogen accumulation), mitochondrial swellings and fusions and development of megamitochondria, loss of cristae, rupture of the mitochondrial outer membranes, relaxation or supercontraction of the myofibrils, vesicular and vacuolar changes of the sarcoplasmic reticulum, oedema of the sarcoplasm, rupture of the sarcolemma. No significant differences of the quantitative parameters could be observed during the ischaemia from 30 min to 4 hrs: myofibrils 53.65--59.74%, mitochondria 26.51--33.59%, sarcoplasm 8.22--11.86%, sarcoplasmic reticulum 1.41--2.63%, lipofuscin 0.05--0.87%, lipids 0.01--0.10%. In comparing the data of the single animals we could determine significant differences between some parameters at the ends of the ischaemic phase and of the reperfusion phase, but as far as the findings are concerned both increases and decreases could be observed. The investigations show that the limit of the reversibility of damages in myocardial cells is about 45 min; in special cases a longer survival time may be taken into account. Reperfusion has different, though not always positive, effects.

Animals↗