Experimentelle Pathologie最新文献

Incorporation of [methyl-³H]thymidine to DNA of lymphocytes cultured in the presence of various concentrations of alpha-fetoprotein (AFP) from human cord blood serum was investigated. It was found that AFP by itself does not exert mitogenic effects. In phytohemagglutinin (PHA) stimulated cultures it may inhibit DNA biosynthesis or exert augmentative effect on this process dependent on the composition of the culture medium.

Autoradiographic, light and electron microscopic investigations on the effect of depot angiotensin on the hearts of rats suggested that the myocardium and the intramural vessels reacted with an activation of the mesenchymal and DNA metabolism already 3 hrs, after the injection of depot angiotensin. The reactions in the capillaries and small arterioles were dominating. Degenerative alterations could be found in the cardiac muscle cells only 9 hrs. after inj ection and culminated in infarction-like necroses and intensive mesenchymal proliferation after the 4th A II injection. Despite further daily applications of A II the degenerative and necrotic myocardial alterations will extensively diminish until the 14th day of experiment, while the mesenchymal activation and the enhanced DNA synthesis in the vessels remained unchanged. Thus an initial stage with the development of disseminated muscle fibre necroses and infarction-like alterations and a stage of compensatory adaptation may be distinguished in the heart after depot angiotensin injections.

Confluent cultures of L-929 cells were incubated at 37 °C for 16 h in serum-free culture medium supplemented with ascorbic acid, β-aminopropionitrile and 5³H-proline and the amount of collagen synthesized in such conditions was evaluated. It was found that addition of platelet homogenate to incubation medium causes significant increase of collagen biosynthesis by these cells.

The incidence and morphogenesis of calcification were investigated by histology, electron microscopy, electron diffraction and X-ray spectrometry in 312 surgically removed human pituitary adenomas. By light microscopy the incidence of calcification was 9 %. The calcium deposits were evident in several adenoma types, but were most frequent and extensive in prolactin-producing adenomas. Histologically, calcium deposits represented amorphous precipitates and psarnmoma bodies staining with hematoxylin, the von Kossa technique and alizarin red. By electron microscopy, calcified deposits were noted in the cytoplasm of adenoma cells and extracellular space. Electron diffraction and X-ray spectrometry of intracellular precipitates as well as psammoma bodies showed the presence of phosphate, calcium and organically bound sulphur with a ratio of 3.5 : 5 : 2, indicating that they contained calcium hydroxyapatite. Present findings provide evidence that mitochondria with microcrystal deposition of calcium represent the primary sites of calcification.

Vesicles attached to the cell membrane of enucleating normoblasts and reticulocytes are considered indicative of the segregation of plasmalemmal components. The vesicles are obviously free from haemoglobin. They bind cationized ferritin and autologous immunoglobulin G. This segregation of plasmalemmal constituents is suggested to be one line of erythroid cell maturation.

Arsenic belongs to the important occupational and environmental agents which can cause damages to the liver by chronic exposure. In a long-term experiment (64 days) in mice the changes in liver cells due to arsenic were studied on the ultrastructural level. The qualitative and quantitative evaluation of the results obtained demonstrate two types of response. The first one was an acute reaction (maximum 4 days) characterized by enlargement of the surfaces of some inner membraneous structures of the hepatocytes (invaginations of the nuclear membrane and undulations of the mitochondrial surface) as well as by loss of glycogen. These changes receded gradually during the course of the experiment. The second type was characterized by a strikingly delayed change (maximum 32 days) represented by the occurrence of dense lamellar structures in the peroxisomes. Both types of response persisted till the termination of the experiment (64 days). The first type of response is considered to be a consequence of the direct toxic action of arsenic, the second one is interpreted as an expression of induced tolerance to arsenic of the organism.

Wistar rats given a single intraperitoneal injection of 75 mg cyclophosphamide revealed dental anomalies in the form of shortening or lengthening of incisors, and development of supernumerary teeth. Rats given additionally 5 mg/kg b. w. of a nitrosomethylurea solution over a period of four months showed the same dental anomalies, but with relatively shorter latency times. In a supplementary investigation examining the effects of benzo(a)pyrene and nitrosomethylurea applied locally to the organon dentale, neoplastic lesions and dental dysplasia were seen.

In weaned pigs endotoxin infusion caused pathological changes in the clotting system typical of consumption coagulopathy and DIC resulting in circulatory disturbances. Infusion of the specific thrombin inhibitor hirudin prevented the endotoxin-induced disorders such as haematological changes, microthrombosis in various organs and the increase in right ventricular pressure and in respiratory rate.

The influence of partial hepatectomy, unilateral nephrectomy and shamoperation on thymocyte proliferation capacity in male rats was investigated. The wet weight and the cell number declines significantly after partial hepatectomy. A stimulation of mitotic activity and H³TdR incorporation on day 3 to day 6 was also observed in partially hepatectomized animals. The polyamine content of the thymocytes was transiently decreased 2 days post partial hepatectomy and shamoperation. Thereafter the amine concentrations increased and remained elevated in the case of partially hedatectomized animals. No significant changes in the content of histamine were observed.

The effect of granulation-tissue extract on the synthesis of collagen in embryonic-chick tendon cells was found to depend on (i) the developmental phase of the granulation tissue, (ii) the concentration of the extract and (iii) the presence of diffusible components in it. The suppressing effect was maximal with concentrated extracts from 2–3-week granulation tissue (where the collagen synthesis is also maximal). The suppressing factor could be enriched by gel filtration chromatography. Cultured human synovial cells were affected like the embryonic-chick cells. When the sponge implant was imbibed with granulation-tissue extract in advance, the developing granuloma contained less collagen than the control.

The stimulating effects with dilute extracts from granulation tissue were due to diffusible components. Blood serum and rheumatoid synovial fluid samples also stimulated collagen synthesis in granulation-tissue slices, less after dialysis.