Biomedical subjects
Publications and source records attributed to U Fuchs.
Perforating eye injuries endanger the eye due to the loss of internal structures; hypertonia; the proliferation of vascular tissue, glia, and epithelium; hemorrhages, and inflammations. This is illustrated with histologic pictures.
The continuing value of Cohnheim's research on microcirculation derives from the triad of in vivo observation, recording of the dynamic features of blood flow in small vessels and measurement of morphologic details. Among Cohnheim's contributions are the concept of the altered vascular wall, the description of the process of emigration and diapedesis by blood cells, the insistence that morphologic observations be interpreted in the light of physiologic data, and the appreciation of the complexity of biologic reactions, in particular those associated with inflammation, shock and diabetic angiopathy.
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The passive transfer of rabbit anti-glucagon antibodies into mice induces periinsular and intrainsular inflammation and hyperplasia of alpha cells. Active immunization of rabbits with heterologous glucagon induces alpha cell hyperplasia.
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A comparison was made of the amount and crystallinity of mineral deposited in the course of the arteriosclerosis in arterial walls in diabetic patients and in individuals with normal carbohydrate metabolism. The macroscopically unchanged tunica intima, fibro-lipidic plaques and bone-like lamellae were taken from aorta thoracalis , aorta abdominalis, arteriae femorales and arteriae coronariae in the course of the autopsy of 17 insulin dependent diabetic individuals and of 9 persons with arteriosclerosis, but with normal carbohydrate metabolism, called control group. The total inorganic constituents in the three kinds of samples were determined by ashing of dried samples at 600 degrees C for 6 h. Crystallinity of mineral was defined as the ratio of the spins connected with the radiation-induced stable paramagnetic centers present in the crystalline lattice of hydroxyapatite crystal, to the total ash content of the sample. An increase in the amount and in the crystallinity of deposited mineral was observed when consecutive stadia of development of arteriosclerotic lesions were compared. This phenomenon resembles the maturation of mineral observed in the course of bone development.
The mitotic index of the hepatocytes is increased 1.7-3.9 fold in rats with Walker and Jensen tumours and in mice with subcutaneous or intraperitoneal Ehrlich tumours. At the same time however, he mitotic activity of the corneal and duodenal epithelia is not changed. So the changes are not found in all organs and tissues. They are relatively specific as to the organism. They are observed to result from different tumours for different species. These results are interpreted as a paraneoplastic effect due to the metabolic requirements of growth processes and their sequels, because the mitotic index is also increased in the hepatocytes of pregnant mice and rats.
Retinas of Rana esculenta frogs were studied by light and electron microscopy in order to establish the photoreceptor layer composition. We found 56% red rods, 9% green rods, 19% single cones, and 16% double cones. This work provides the morphological basis for electrophysiological investigations concerning the mass receptor potential of isolated Rana esculenta retinas.
Poststenotically developing aggregates of erythrocytes aggravate the recirculation of the blood vessel after removal of the obstruction. This is shown in model experiments in which blood vessels are observed vital-microscopically for a longer time. Place and extension of the diminished postischaemic blood circulation are variable and depend on the different size, the deformability, the adhesivity and localisation of the aggregates or erythrocytes.
Compared with control animals with a normal metabolism, rats with insulinopenic diabetes generally show an increase in glomerular deposition of complement-fixing immune complexes after immunization with bovine albumin and bovine gamma-globulin. Compared with the control group, the serum of the diabetic animals showed a reduction in the titers of IgM-isotype antibodies, which have a lower affinity. The concentration of the circulating immune complexes is the same. The increased frequency of glomular deposits in experimental diabetes can be explained by an increase in capillary permeability and by the formation of qualitatively different immune complexes.
Because of a reduction in the rate of phagocytosis by the reticuloendothelial system, the removal of large doses of colloids from the blood is much slower in rats with experimentally induced insulinopenic diabetes than in controls having a normal metabolism. This kinetics corresponds to the exponential response reported in the literature for an injected dose exceeding the "critical dose", with phagocytosis being a crucial parameter. In the case of smaller doses of colloids, however, clearance follows a different kinetic pattern which is here formulated mathematically. It is determined largely by the rate of liver blood flow. In this case, it is not possible to obtain statistical evidence of differences between diabetic and normal rats on administration of gold. Colloidal gold and so-called biological ink proved themselves extremely useful for quantitative studies of phagocytosis, whereas indium proved to be unsuitable under the experimental conditions used in these studies.
Using labeled albumin, the permeability index was determined for the aorta and other arteries of the rabbit after different circulation times. The results were reproducible. Different indices of permeability were obtained for different arteries. When the circulation time of the tracer was extended, the increase in the permeability index was greater for the coronary and femoral arteries than for the aorta. 5-hydroxytryptamine, bradykinin and prostaglandin E2 tended to increase the permeability index. There was no relation to the level of blood pressure. The different indices of permeability obtained for the different arteries were not leveled by the mediators. The permeability index is seen to become greater postmortally.
8 rabbits were immunized with isolated fractions of renal glomerular basement membrane of 18 human diabetics and 18 human controls. The antisera were tested with the indirect immunofluorescence at frozen kidney sections of 31 longtime diabetics and 31 controls. One part of the sera was absorbed with isolated glomerular basement membrane of both groups before. In 30% of the diabetics we found antigens which were not observed in controls. Therefore, we conclude that a part of the diabetics produce not only too much but also a changed extracellular matrix in the glomeruli.
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A quantitative exploration of retinal cell content was carried out in diabetics and metabolically healthy controls of the same age and sex distribution. After diabetes of 6 years duration there was a drastic diminution of cells in the ganglion cell layer of the central retinal area, while the number of cells of the inner nuclear layer was slightly reduced and that of the outer nuclear layer was still unchanged. The periphery of short duration diabetic retinae showed a normal cell content in all nuclear layers. In long-term diabetes (about 10 years), significant diminutions in cell numbers were found in all layers of both the retinal center and periphery. The described cell deficits are accounted for by disturbances of retinal microcirculation. After a relatively short duration of diabetes, blood flow interruptions in the area supplied by the central retinal artery occur; in long-term diabetics the chorioidal vessels are also affected. Connexions between the cell-deficit pattern and functional (electrophysiological) findings are discussed.
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