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Biomedical subjects

W Hort

Publications and source records attributed to W Hort.

137 records · Page 8Linked to original sources
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Myocardial hypertrophy. Light microscopic findings on the myocardium. Blood supply. Ventricular dilatation and heart failure.

The heart is an organ with an almost constant number of muscle cells under physiological conditions. But beyond the critical heart weight (500 g) there is an increase in the number of muscle fibers (hyperplasia) and a similar increase in the number of capillaries. The relation of 1 capillary to 1 muscle fiber remains constant. During physiological growth there is a rather close correlation between the growth of human coronary arteries and the growth of the myocardium. Under pathological conditions the growth of coronary arteries is slower than that of the myocardium. In many animal species investigated up to now there is a rather close correlation between the diameter of coronary arteries and the diameter of the heart. As a rule, hearts with chronic insufficiency are dilated. They work under unfavourable geometrical conditions. The post-mortem ventricular volume is influenced to a very great degree by rigor mortis.

Animals↗
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[Organization of experimental thrombi in arteries and veins. A comparative study (author's transl)].

Thrombi were produced in 62 female white rats (Sprague-Dawley) by injection of thrombin in the right common carotid artery and in the left vena iugularis as well. Partly the vessels were ligatured proximal and distal of the thrombus, partly they were closed with one ligature. In this latter group (one ligature) the thrombus was exposed to the blood-pressure, while in the first group the thrombus was protected against the blood-waves. After 2, 4, 6, 8, 10 and 14 days as after 4 and 6 weeks the rats were sacrificed and the thrombosed vessel-segments were studied by light-microscope. In the arterie we found occlusive thrombi. In the veins the thrombi were higher in fibrin content than in the arteries. Between the thrombus and the endothelium of the vein-wall there was a sinus which became wider with aging of the thrombus. In the first days the progression of thrombus-organization was more rapid in veins than in arteries; endothelial cells, fibroblasts and capillary buds invaded the thrombus more extensive. In veins there was no difference in composition and organization of the thrombi of the two groups. In the thrombosed veins often small capillaries could be seen running through the vessel wall into the tissue of the organized thrombus but not in arteries. 6 weeks after thrombus-formation wide capillaries recanalized the veins, but the arteries were obturated by fibrous tissue with only a few small capillaries. Elastic fibres could be seen in the organized arterial thrombi earlier and more extensive than in the venous. In double ligatured arteries the organization of thrombi was more rapid than in arteries, in which the thrombus was influenced by the pulsating blood-pressure. In this latter group with only one ligature the organization-process was pronounced in the proximal part of the thrombus, which was higher in fibrin content. Next the ligature the thrombus was composed mainly of erythrocytes and hematoidin-needles. In this part of the thrombus the organization-process started with delay. From our findings we may conclude that the composition of a thrombus, the influence of the blood-pressure and the structure of the vessel-wall are important factors to explain the different temporal course and morphological pattern of thrombus-organization.

Animals↗
PubMedDate not supplied

Experimental coronary artery occlusion. I. Measurement of infarct size.

We studied the size of infarcts in 25 dogs 48 hrs after proximal occlusion of the left anterior descending coronary artery. In one group of animals infarct size was measured by histologic criteria, in another group the infarct was measured macrohistochemically using p-NBT and malate to incubate unfixed slices of myocardium. In both groups infarct size was expressed as percentage of the area of perfusion of the occluded artery. Infarct size was 72% of the area-at-risk in the group studied by histology and 74.5% in the macrohistochemical group. The satisfactory agreement of both methods favors the p-NBT technique because of its ease and speed. It is suggested that the expression of infarct size as percentage of the perfusion area is a good definition and should be used in experiments designed to manipulate infarct size. In this way differences in the size of occluded arteries and their respective perfusion areas have no or only a negligible influence on infarct size.

Animals↗
PubMedDate not supplied

Diameter of coronary arteries in 36 species of mammalian from mouse to giraffe.

Systematic quantitative investigations were performed in the coronary arteries of 102 hearts of 36 mammal species with an overall more than tenthousandfold difference of their heart weight. After postmortem coronary angiography with a filling pressure of 100 mm Hg x-rays were taken, and the widest diameters of the coronary artery stems were determined. We found a nearly linear correlation between diameter of a standardized coronary artery and virtual diameter of heart, but the increase in diameter of coronary arteries exceeded somewhat that of the diameter of heart especially for heart weights surmounting 100 g. Perhaps relative enlargement of coronary arteries in the bigger hearts contributes to the prevention of large increase of blood flow velocity.

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PubMedDate not supplied

[Distribution of the lymph vessels in the mouse heart. A light and electron microscopic study (author's transl)].

The lymphatic system in normal mouse heart was investigated by light and electron microscopy. Lymph vessels were only demonstrated in the subepicardial layer and the outer half of the myocardium. Here above all they were situated in close vicinity to arteries and thin-walled veins, rarely separated in the interstitial space, never in the subendocardial layer of the left ventricular wall. The myocardium contains only 2 lymph vessels per mm2. By means of electron microscopy all lymph vessels were regarded as lymph capillaries. Their ultrastructure is described in detail. This investigation shows that lymph vessels in normal heart are rarer than supposeed till now. It is possible that most of the ultrafiltrated fluid is drained by the cardiac venous system, while the lymphatic system only has to transport a small amount of protein-rich fluid.

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PubMedDate not supplied

Differentiated DNA analysis in relation to steroid receptor status, grading, and staging in human breast cancer.

Flow cytometric DNA analysis was performed in 100 cases of human breast cancer. Using a category system of six ploidy groups, ploidy status was distributed as follows: The majority of the neoplasias were either diploid (45%), hyperdiploid (21%), or tetraploid (15%), whereas the remaining marginal ploidy groups, i.e. hypodiploid (4%), hypertetraploid (9%), and multiploid (6%) were less frequent. In an attempt to evaluate the prognostic significance of DNA content, ploidy status was correlated with steroid hormone receptor status, histopathological grade, and TNM data. The higher incidence of negative estrogen and progestin receptor status and higher histopathological grade in hyperdiploid malignancies was significantly different from the prognostically more favorable positive receptor status and lower grade in diploid tumors. Tetraploid neoplasias statistically resembled the latter group with respect to both parameters. As far as TNM data are concerned, tendencies towards less favorable staging were observed in hyperdiploid as compared to diploid and tetraploid tumors. A definite statement of the prognostic significance of the marginal ploidy groups cannot be made at present. In order to characterize diploid malignancies more closely, proliferative activity expressed by %S-phase was analyzed. Steroid receptor status of diploid tumors exhibiting more than 6% S-phase did not differ statistically from that of hyperdiploid neoplasias. In contrast, diploid tumors expressing less than 6% S-phase closely resembled tetraploid ones. Our data emphasize the prognostic significance of differentiated DNA analysis.

Breast Neoplasms↗