Experimentelle Pathologie最新文献

Light microscopic and electron microscopic findings in thymuses from 4-week old feline leukemia virus-infected and 4- and 9-week old noninfected kittens were evaluated and found to be morphologically similar to each other. Thymuses from 9-week old feline leukemia virusinfected kittens were markedly atrophied and individual lobules within each thymus varied in the severity of atrophy. Lobules having the least severe atrophy had a moderate thinning of the cortex and a heterogeneous thymocyte population arranged in disorganized cords. Additional morphologic changes in these thymuses included intense eosinopoiesis at the corticomedullary junction, increased prominence of vasculature, and enlarged Hassal's corpuscles. In addition to these changes lobules of thymus having the most severe atrophy had a marked cortical thymocyte depletion, lobule collapse, and increased numbers of mast cells. Degeneration of epithelial cells in most lobules was indicated by electronlucency of the cytoplasmic matrix and often greatly dilated rough endoplasmic reticulum.

From 16 synovial membranes of patients with rheumatoid arthritis morphological parameters as well as the GAG distribution pattern have been determined using 2 methods each. The results were checked by discriminant and regression analysis:

The total GAG concentration of the synovialis was significantly correlated with the sum of the parameters “fibrin in organization”, “granulocytes” nad “necroses” (acute activity).

A highly significant correlation between the age of patients and the severity of chronic morphological alterations (basic activity, especially proliferation) was found.

The percentage of CS plus DS was positively correlated with the age of patients as well as with the basic activity of the disease, especially with the proliferation. — Contrary to this, HA was significantly decreased when related to the “chronic” parameters.

No correlation could be demonstrated between the GAG components and criteria of the acute activity.

The evaluating system of Stiehl and Geiler is to be preferred for obtaining morphologic-biochemical correlations.

Furthermore, a diagram is proposed demonstrating the cumulative progression of rheumatoid arthritis in the synovialis as related to the GAG pattern. Its combination with morphological data (scars, proliferation, exudation) may help to describe the development of the disease more acurately.

Liver regeneration is distinctly influenced by the treatment of male Sprague-Dawley rats with 2-acetylaminofluorene or N-metriyl-N-nitrosourea on three successive days immediately prior to-partial hepatectomy. The latter compound modulates the restorative liver growth, whereas it is strongly inhibited by the hepato-carcinogen 2-acetylaminofluorene. According to their influence on the regenerating liver, both carcinogens delay the post-operative decrease as well as the recovery of the physiological cell renewal in the jejunal and esophageal epithelium. Beside this, the circadian mitotic fluctuation of the esophagus is also altered by the carcinogens after partial hepatectomy like that of the regenerating liver. In contrast to the behaviour of the jejunum and the esophagus, the adrenocortical cell division is temporally elevated by the growth stimulus after partial hepatectomy. This effect is also found after carcinogen pretreatment only. For that reason one can assume that carcinogens produce a growth stimulating response like partial hepatectomy, which is displayed by an increased cell replication in the adrenal cortex. Possibly this phenomenon reflects common systemic mechanisms which indicate the promotory action of partial hepatectomy and chemical promotors as well as that of carcinogens.

Administration of a high dose of disodium edetate (Na₂-EDTA) caused an excessive proliferation of bronchiolar epithelia. This phenomenon may be related to the rapid and severe removal of fixed calcium ions from the cell surface induced by the high dose of Na₂-EDTA.

The incidence of periendothelial (epi-, inter- and subendothelial) round cells in en face endotheliumintima preparations and cross-sections of swine aortas was determined. The round cell count of Sudanpositive and -negative intimai areas of thoracic and abdominal aortas of animals fed an atherogenic diet was compared with Sudan-negative areas of animals on normal food. Furthermore, spontaneous lesions at the aortic trifurcation in swine and abdominal aortic segments of humans with different stages of arteriosclerosis were studied and the aorta endothelium of normal animals was examined with a scanning electron microscope. According to these studies, round cells (monocytes or lymphocytes occur in the subendothelium as a normal constituent of the aortic intima. They are increased in spontaneous lesions and more frequent in induced fatty streaks. In swine, they participate primarily in intracellular lipid storage in Sudan-positive intimal areas. Their function in normal intima and in low-lipid intimal thickening is unknown. Similar observations were made with regard to the human abdominal aorta.

Alterations in enzyme induction are well known to occur in the liver of animals after administration of carcinogens. This effect is believed to be specific to carcinogens. If this is true, it might be utilized for testing chemical substances for carcinogenicity. To obtain further information about this process, the dietary induction of the activity of PGI and PGK in livers of 3-day fasted rats before and after a 30 hour refeeding period with 60 % sucrose diet was investigated after feeding a 0.03 % AAF-containing diet for 2 or 4 weeks.

The induced acitvity of PGI was statistically significantly lower in the animals pretreated with the carcinogen for 2 or 4 weeks than in the nontreated control animals, even after subsequent feeding carcinogen-free diet for 2 weeks.

Refeeding led to a pronounced induction of PGK activity solely after 2 weeks duration of the experiment. In contrast to PGI, the activity of PGK estimated after refeeding was significantly higher in the rats pretreated with AAF for 2 and 4 weeks than in the non-treated control animals. However, in the rats fed AAF, the basal level of activity estimated after fasting was elevated to a similar extent and, therefore, enhanced induction does not seem to be the cause of this effect.

For testing the biocompatibility of dental materials in an experimental animal model the capsular tissues around the implanted dental materials were examined light and electron microscopically. The exudative inflammation and fibrosis at different times after implantation were thought to be the indicators of the degree of the compatibility. Starting from the knowledge of the occurrence of myofibroblasts in reparative granulation tissue we looked for such cells in the capsular tissues. Myofibroblasts were especially found at three weeks after onset of the experiments. Structural peculiarities of this fibroblast modulation are emphasized. Myofibroblasts are considered as an essential link between the early exudative reaction and the late fiber formation in tissue reactions after mechanical injury.

The mitotic activity of the adrenal cortex shows diurnal variations. Irrespective of these fluctuations, single doses of 2-acetylaminofluorene selectively stimulate cell division in the zona fasciculata. The serum from 2-acetylaminofluorene-treated rats also acts mitogenically after transfer to intact recipients. After simultaneous administration of 3-methylcholanthrene and 2-acetylaminofluorene the mitotic action of the serum is lost. The proliferative response of the adrenal cortex is supposed to be systemically mediated by growth factors which are induced by the carcinogen.

The effects of the specific active cancer immunotherapy utilizing autologous tumor tissue particles polymerised with ethylchlorformiate, and used in combination with PPD tuberculin, were studied with respect to the growth of mastocytoma (P-815×2) in DBA/2 mice. As a control material, animals not immunised or immunised only with the nonspecific reticuloendothelial system stimulator, PPD tuberculin, were used.

The frequency of the tumor metastases in the organs surveyed (lymph nodes, spleen, liver, kidney, lung and thymus) was lowest in mice having received the specific immunotherapy regimen. Similarly, the signs of tumor rejection by the host (tumor-associated fibrous scar, lymphocyte and plasma cell infiltration, and disappearance of the tumor tissue totally or subtotally) were found to be most pronounced in this series of mice.

The findings were discussed against the background of the successful clinical trials made with this mode of specific cancer immunotherapy during the recent few years in patients whose neoplasia had escaped the reach of conventional cancer therapy. The findings were also discussed in the light of the mechanisms involved in cancer immunity in general, and a conclusion was drawn that this kind of specific active cancer immunotherapy seems to exert beneficial effects on the host's immune system, and thus seems to contribute to tumor rejection by the host.

Not only insulin application but also permanent treatment with adrenalin leads to adrenalin depletion of the adrenal medulla. Unilateral sympathectomy and subsequent treatment with insulin or adrenalin shows that in both cases adrenalin depletion is triggered by hypoglycaemia and activation of the sympathico-adrenal system. Therefore, a permanent elevation of the adrenalin level is sufficient to achieve depletion of the adrenal medulla, without necessitating a rise in the level of an additional hormone (insulin).