Acta morphologica Hungarica最新文献

The macromolecular composition and ultrastructure of the myotendineal junction (MTJ) of slow-twitch (type 1) and fast-twitch (type 2) muscle fibers were studied in the gastrocnemius-soleus-Achilles unit of the rat. Both proteoglycans and glycosaminoglycans, type III collagen, fibronectin and laminin could be detected at the MTJ. Due to membrane folding, finger-like processes were seen at the myotendineal junction. The processes of the type 1 fibers are greater in size, however, due to subdivisions, the processes of type 2 muscle fibers had a greater surface than type 1 fibers. The macromolecular composition is similar in both type 1 and type 2 muscle fibers.

The cellular localization of the p21 protein was studied by immunoelectron microscopy in human fibrosarcoma cells with different N-ras gene expression. The tumorigenic HT1080 cells-expressing equally the normal and mutant N-ras genes-contained the p21 in the plasma membrane, in pinocytotic areas as well as in the intracellular vesicles. The non-tumorigenic revertants-expressing more normal N-ras gene than the mutant one-contained p21 in the plasma membrane, especially at the cell junctions. These results suggest, that the mutant p21 may locate to the membrane areas connected with pino- or endocytotic functions.

The connective tissue content of four different human liver tumors (Fibrolamellar carcinoma, FLC; hepatocellular carcinoma, HCC; focal nodular hyperplasia, FNH and hepatocellular adenoma, HCA) was investigated by computer aided morphometry. A significantly higher connective tissue content was found in FNH and FLC as compared to HCA and HCC. The distribution of the connective tissue was homogeneous in the cases of FNH, HCA and HCC, while a highly unhomogeneous distribution was observed in FLC cases.

NK/Ly mouse lymphoma ascites cells were explanted and established in culture. The cells grew in monolayer and showed fibroblast-like morphology. The original NK/Ly cells contained one large metacentric marker chromosome, while the in vitro growing cells had two metacentrics in the early passages. These so-called bi-armed chromosomes were growing in number, up to seven, along with the number of subcultures. No tumour "take" was observed when the cells were given into mice intraperitoneally. However, a solid tumour developed following injection of cells into the leg muscle. The histological picture of this solid tumour was anaplastic sarcoma. It is concluded that the accumulation of bi-armed chromosomes, which were formed either by anaphase bridges, or by centric fusion of telocentric chromosomes, led to a profound alteration of lymphoma resulting a phenotype of anaplastic sarcoma.

The phenomenon that the autologous human platelets can be phagocytosed in vitro by neutrophils and monocytes of healthy human donors (being free of antiplatelet autoantibodies) was demonstrated earlier. In this study we have confirmed electron microscopically the phenomenon of phagocytosis. Besides, using flow cytometric analysis, we have shown that a possible way for the bridge-formation between the washed platelets and neutrophils can be the linkage via IgG + C3b complexes bound to the Fc receptors of platelets. This mechanism supposedly may play a role also in the clearance of platelets by peripheral phagocytes in vivo.

Peritoneal macrophages obtained from 30 patients with end-stage kidney treated by intermittent peritoneal dialysis and from 30 subjects with normal renal function (relative control) were investigated by light microscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Two populations of peritoneal macrophages were distinguished in both dialysed and control patients. In the former group, the main population consisted of macrophages similar to monocytes from peripheral blood, while the majority of macrophages in control patients showed larger size, more prominent vacuolization of the cytoplasm and stronger spreading on glass surface.

The authors have found morphological alterations identical with hyperfiltration glomerular injury in the renal biopsies of 23 out of 100 patients with IgA nephropathy. In 15 of them the lesions were similar to the different stages of segmental glomerular hyalinosis and sclerosis with deposition of IgM and C3. At the time of renal biopsy, the serum creatinine of all except 8 patients was normal (maximally 170 mumol/1), only 13 had hypertension, and all except 2 were proteinuric. During the follow-up period (mean +/- 2Sd = 138 +/- 76 months) all of them became hypertensive. In 10 patients end-stage renal failure developed, and in another 10, serum creatinine also became elevated (range 124 - 504 mumol/1). On the basis of these data the development of focal segmental hyalinosis and sclerosis should be interpreted as a bad prognostic sign in IgA nephropathy.

The sequentional changes of some morphometric parameters (lymph node weight, high endothelial venule (HEV)-content) after an antigenic challenge (sheep red blood cell; SRBC) and the alterations of HEV-function (HEV-adhesiveness measured with a HEV binding assay) were studied in rat lymph nodes over a period of seven days with daily measurements. Authors suggest that the proper estimation of the HEV-content of a lymph node in a HEV binding assay allows to express the HEV-adhesiveness numerically, and to compare the data obtained by this assay quantitatively. The HEV-adhesiveness is the strongest on day 6 after the antigenic challenge, the early increase in weight on day 2 is attributed to an increased blood flow and the changes in the HEV-content are presumed to reflect a simple dilation of HEVs (on day 2) and later (on days 4 and 5) an increase in the height of high endothelial (HE) cells. A crucial role is ascribed to the altered HEV-adhesiveness in the increase of lymphocyte migration to the challenged lymph nodes.

One hour after treatment with 3H-benzpyrene, grains appeared for the most part above the hepatocellular surface, heterochromatin and dense vacuoles, whereas 24 h later they were associated mainly with the dense vacuoles and smooth-surfaced endoplasmic reticulum and only, a few were still present above the heterochromatin. Neonatal pretreatment (imprinting) with benzpyrene accounted for an earlier appearance of benzpyrene in the hepatocytes relative to the non-pretreated control, but while labelled benzpyrene had practically disappeared from the liver of imprinted rats within 24 h, it still persisted in the liver of control rats at a level approximating the 4 h value.

Arteries were investigated ultrastructurally in material from 40 needle and wedge biopsies of renal allografts, and immunohistochemically in another 10 cases with signs of chronic obliterative transplantation arteriopathy. In the early biopsies, but even in the control kidneys, thin extensions of the smooth muscle cells of the media were observed, which were in direct contact with the endothelial cells through the lamina elastica interna. These extensions may contain receptors mediating endothelial noxae to the smooth muscle cells thus initiating their proliferation, migration to the intima presumably begins in the early post-transplant period and continues until the lumen is occluded. Concomitantly, inflammatory cells (mainly macrophages, with a smaller number of CD4 and CD8-positive T lymphocytes) invade the intima. The proliferating myointimal cells, possibly having become HLA-DR-positive, may behave as antigen-presenting cells, enhancing the anti-graft immune response further, and aggravating the arterial injury.