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Background: Histopathologic and morphometric analysis of the internal limiting membrane (ILM) in diabetic eyes was performed. The thickness of the ILM was correlated with the level of glycosylated hemoglobin (HbA(1C)) and other clinical factors., Methods: The prospective study involved 56 eyes of 52 diabetic patients with a mean age of 63 +/- 7.6 years. Vitrectomy with trypan blue-assisted ILM peeling was performed in the standard way. The mean follow-up period was 8.7 months (range 3-19 months). The ILM was fixed immediately after peeling in 2.5% glutaraldehyde and submitted for electron microscopic evaluation. The ILM was photographed at standard magnification (x5,000) with the scale of 1 microm in the shot., Results: Morphometric analysis demonstrated a significant thickening of the ILM in all eyes, with a mean thickness of the ILM of 3.61 +/- 1.22 microm. It was found that a higher thickness of the ILM is related to elevated HbA(1C) in both types of diabetes mellitus (DM) (p = 0.040). We also found significant dependence of ILM thickness in relation to duration of DM by comparison of men and women (p = 0.026), and a significant correlation between ILM thickness and the age of diabetic patients related to their gender (p = 0.029)., Conclusions: We confirmed increased thickness of the surgically peeled ILM and statistically significant correlations to elevated HbA(1C) in both types of DM, and to further clinical characteristics of case series. Morphometric and histopathologic analyses of the ILM contribute to more objective evaluation of the ultrastructure of the vitreomacular interface.

Background: The highly swelling poly (glycerol monomethacrylate) gel (polyGLYMA) and hydrophilic polymer poly (triethylenglycol monomethacrylate (polyTEGMA) were tested as potential viscoelastics for intraoperative use in anterior segment surgery., Methods: PolyGLYMA was implanted into the anterior chamber in 5 rabbits, and 40% polyTEGMA in 16 rabbits. The eyes were enucleated 1 week to 3 months after the operation. The corneal endothelium was examined with specular microscopy, and then the whole eye histopathologically., Results: In all eyes of the polyGLYMA group, the clinical findings were characterized by a marked ciliary injection and severe secondary glaucoma, and the histologic ones by a marked inflammatory infiltration and thickening of Descemet's membrane in the anterior chamber angle. Specular microscopy revealed a decrease in the endothelial cell density and polymorphism of the endothelial cells. In the polyTEGMA group, the anterior segment and the fundus were physiologic all the time, and specular microscopy and histologic findings showed no degenerative and/or inflammatory changes., Conclusions: PolyGLYMA proved unsuitable for intracameral application in rabbits. The new polymer polyTEGMA is characterized by high biologic tolerance after its implantation into the anterior chamber of rabbits. PolyTEGMA 40% might be considered as a potential viscoelastic material in humans.

Seven cases of pseudomalignant ossifying myositis with a typical clinical symptomatology have been reported. None of the cases had experienced an injury. All the lesions were intramuscular and all of them showed a zonal arrangement. Electron microscopy in three cases allowed the demonstration of cells showing morphological features of myofibroblasts and monocytic cells of the macrophage type. These previously unreported features together with the zonal pattern of the lesions indicate their reparative nature.

Tumour tissue surgically excised from 10 patients bearing Ewing's tumour of bones was examined electron microscopically and histoenzymologically. In all cases the tumour was composed of polygonal cells with cytoplasm poor in organelles but with conspicuous aggregates of glycogen particles. There were numerous intercellular connections of desmosomal type and a distinct cell membrane bound positivity for alkaline phosphatase activity. In two cases in which there was a negative reaction for alkaline phosphatase, the lack of enzyme activity might have been related to cytotoxic treatment carried out for several months immediately before excision of the tissue used for histoenzymological studies. The problem of histogenesis of Ewing's tumour remains unresolved although some of the present findings support a haemangiogenic origin of the tumour.

A histochemical study of enzymatic activities was undertaken in five cases of histiocytosis X (two localized bone forms, two generalized forms, and one involving mainly the skin), each of which revealed characteristic structural features at the optical and ultrastructural levels. A confirmation was made of the original assumption of high acid alpha-D-mannosidase activity, i.e. activity described in human Langerhans intraepidermal cells (Elleder, 1975). In the control group of tumors, with the exception of urticaria pigmentosa, enzyme activity was either at trace level or altogether absent. Acid alpha-D-mannosidase activity therefore appears to be the first biochemical feature common to both histiocytosis X and the Langerhans cells. The significance of the finding for the present theory of the histogenesis of the above tumors is discussed.

Electron microscopic examination of three adamantinomas of long bones revealed structures usually observed in both mesenchymal and epithelial tumours. Tumour cells showing high alkaline phosphatase activity frequently tended to line clefts in connective tissue, resembling endothelial cells. The long processes of such cells showed fenestration. In areas showing fibre production the tumour cells were in close relationship to collagen fibrils. The latter were found, together with microfibrils, between the processes and above the basement membranes. The tumour cells were interconnected by desmosomes with tonofilaments and contained numerous bundles of microfilaments. All three cases revealed tiny intracytoplasmic inclusions resembling Weibel-Palade endothelial bodies. In addition, some of the structures in the lumena contained definite acid mucosubstances. A squamous cell pattern was present in only one of the three specimens. The coincidence of divergent structures in a single specimen has led us to the conclusion that the so-called adamantinoma of long bone might be possibly related to tumours of mesodermal or mesectodermal origin.

The ultrastructure of xanthogranulomas developing during obstructive suppurative pyelonephritis was studied in rats with a permanent ligature of one ureter and an intravenous injection of E. coli suspension. The xanthogranulomas consisted of macrophages with numberous phagolysosomes containing rests of phagocytosed polymorphonuclear leucocytes and bacteria. Lipids identifiable as triglycerides were found in such cells particularly as isolated intracytoplasmic droplets and, less frequently, within the phagolysosomes. The source of isolated intracytoplasmic lipid droplets within the macrophages has remained obscure. Their origin in the macrophages by synthesis could not be excluded, similarly as in the polymorphonuclear leucocytes. PAS positive cells occurring as late as 2 months after the beginning of the experiment at the periphery of xanthogranulomas contained multiple intracytoplasmic vacuoles, most probably phagolysosomes. These cells, with high probability the oldes ones of the macrophagic population in the xanthogranulomas were virtually devoid of lipid droplets.