[The effect of bevacizumab on the ultrastructure of choroidal neovascular membranes in patients with age-related macular degeneration (AMD)]. / Der Einfluss von Bevacizumab auf die Ultrastruktur choroidaler Neovaskularisationsmembranen bei Patienten mit altersbedingter Makuladegeneration.

BACKGROUND: Age-related macular degeneration (AMD) is a disease with high social impact that severely hinders the quality of life of the affected patients. The aim of our study is to examine the ultrastructural changes in the choroidal neovascular membranes occurring after the intravitreal administration of Avastin. MATERIAL AND METHODS: In our study we enrolled 24 AMD patients. Only 9 of them were treated with intravitreal injections of Bevacizumab (1.25 mg). Later on in all cases due to complications of the disease pars plana vitrectomy with excision of the subretinal membranes was performed. The subretinal membranes taken directly from the eye during the operation have been studied by transmission and scanning electron microscopy and with Safranin O. RESULTS: Subretinal membranes in AMD patients consisted mainly of fibroblasts, isolated or grouped RPE cells and elements of blood. Numerous capillaries of subretinal blood vessels were also found. Their walls consisted only of one thin layer of fenestrated endothelial cells. The endothelial fenestration in the Avastin-treated patients was significantly reduced. Densely packed thrombocytes and erythrocytes occluded the capillary lumen. Some of the RPE cells showed alterations. The number of proteoglycan complexes in the matrix was significantly increased. CONCLUSION: Our results indicate that intraviterally administered Avastin causes changes in the new vessel walls and in the extracellular matrix components. It diminishes the fenestration of the endothelial cells but also increases the risk of vessel occlusions and may have an alterating effect on the RPE cells. Although Avastin has the potential to improve the quality of life, patients subjected to the treatment should be carefully selected and constantly monitored.

[Comparative ultrastructural analysis of the proliferative tissue in PDR patients with or without vitreous haemorrhage: from ultrastructural approach to clinical practice]. / Ultrastruktureller Vergleich des proliferativen Gewebes bei PDR-Patientenmit und ohne Glaskörperblutung--von Grundlagenforschungen zu den klinischen Therapien.

BACKGROUND: Proliferative diabetic retinopathy (PDR) is a sight-threatening disease with high social impact, easily complicated with vitreous haemorrhages (VH). In our study we try to point out the ultrastructural differences between proliferative tissues in PDR patients with and without vitreous haemorrhage in regard to the clinical practice and proper timing of vitreo-retinal surgery. MATERIAL AND METHODS: In our prospective study we included 27 PDR patients (18 with PDR only and 9 with PDR and vitreous haemorrhage). All of them were later operated with pars plana vitrectomy, during which proliferative tissue was collected. The materials were examined with transmission and scanning electron microscopy and histochemically with Safranin O. RESULTS: The proliferative tissue of PDR patients without VH was mainly comprised of fibroblasts, macrophages and glial cells. We found a variety of blood vessels. Most common were the capillaries of "mature" new vessels. In the proliferations of patients with VH, macrophages and erythrocytes were more commonly detected. In the tissue capillaries of young new vessels prevailed, with only a very thin layer of endothelial cells comprising their walls. In the extracellular matrix among the proteoglycan complexes, we found lots of residual elements of blood. CONCLUSIONS: Our results point out that blood in the vitreous cavity alters the ultrastructure of the existing PDR proliferations in respect to making them more rigid and prone to contractions. It is therefore important to consider vitreous haemorrhage in PDR patients as a very serious complication, requiring in some cases urgent vitreo-retinal surgery.

[Alterations in the structure of the epiretinal membranes in PVR -- assumptions and reality]. / Ultrastrukturelle Veränderungen in der Struktur epiretinaler Membranen bei PVR -- Anspruch und Wirklichkeit.

BACKGROUND: Proliferative vitreoretinopathy (PVR) is known to be the main cause of failure for routine retinal detachment surgery. Our aim was to document the ultrastructural changes in the epiretinal membranes in cases of PVR. MATERIAL AND METHODS: Epiretinal membranes were taken during vitrectomy of 64 patients with different stages of PVR and further analysed using transmission and scanning electron microscopy. RESULTS: In the early stages of the disease mainly retinal pigment epithelial (RPE) cells, fibroblasts and occasional glial cells were found. Moreover, some of the RPE cells showed altered characteristics. In contrast, epiretinal membranes from the developed stages of PVR were comprised mostly of fibroblasts and a considerably diminished number of RPE cells. Cells with marks of degeneration were generally found. CONCLUSIONS: Our results point out that epiretinal membranes in PVR are dynamic structures, constantly changing their cell and matrix composition with the progression of the disease. The morphological changes together with the clinical data are important points to consider when discussing the most appropriate therapeutic approach for each case.

Ultrastructural changes in the transitional zone between articular cartilage and synovial membrane during the development of experimental osteoarthrosis.

We studied the ultrastructural changes that take place in the transitional zone between the articular cartilage and the synovial membrane during the development of experimental osteoarthrosis. We focused special attention on changes involving the proteoglycan complexes within the matrix of articular cartilage. We observed that changes in the transitional zone resemble those seen in articular cartilage during the development of osteoarthrosis. We also found transient cellular forms with fibroblast phenotype regulating the demands of both cartilage and synovial matrix. The transient nature of these elements determines the pronounced lability of this zone, and this may be related to the early development of osteoarthrosis.

Ultrastructural changes in the synovial membrane in experimentally-induced osteoarthritis of rabbit knee joint.

Rabbit knee joint osteoarthritis was induced by intraarticular injections of a 10% sterile NaCl solution. Within 30 days the synovial membrane had undergone hyperplasia resulting in activated synovial fibroblasts. Transitional forms of synoviocytes as well as activated synovial macrophages were a very common finding. At 60 days a thickening of the synovial intima was perceptible. Most of the synoviocytes were of the fibroblast type. Transitional cell forms abounded. An increase in collagen fibres and capillaries of the fenestrated type occurred in the intercellular spaces. In the deep layer collagen bundles had formed between which activated fibroblasts and macrophages were noticed. The described changes point to an active participation of the synovial membrane in the destruction of articular cartilage in osteoarthritis.

Changes in the distribution of proteinpolysaccharide complexes within the articular cartilage in experimental osteoarthrosis.

The quantity and type of proteinpolysaccharide complexes in the matrix determine up to a great extent the mechanical properties of articular cartilage. It is the purpose of this study to evaluate the changes in the mentioned matrix components against the background of experimentally induced osteoarthrosis. As shown by electron microscopic and morphometric studies, the changes in the superficial layer are promptly occurring and clearcut, whereas those in the deep layers are recorded in late observation terms only. A reduction of proteoglycan quantity is noted with a simultaneous differentiation of their fine structure in the various stages of osteoarthrosis development. Initially the alteration in the cell organization of chondroblasts is associated with occurrence of differences in proteoglycan content, and subsequently--in the collagen structures of the matrix too.

[Changes in the articular and growth cartilage of young rats after the intra-articular injection of hydrocortisone]. / Promeni v stavniia i rastezhniia khrushtial na mladi plukhove sled vutrestavno inzhektirane na khidrokortizon.

Changes in the cells and matrix of the joint cartilage (JC) and growing cartilage (GC) of tibias of young rats after five-fold administration of hydrocortisone in a dose of 10 mg/kg of body weight were studied by routine histological and histochemical methods. Fissures occurred in JC, but its superficial layer thickened. The cells of this layer acquired the form of fibroblasts, but the reaction for proteoglycans gradually weakened and became negative. The cells in the proliferative and hypertrophic zones were involved mainly in GC. The amount of granulated endoplasmic reticulum diminished. The number of myelin-like figures was increased. Pilings of thick collagenous fibers occurred in the matrix.

Clinical-morphological and electron-microscopic studies of the growth plate in solitary bone cysts.

The occasional humeral growth retardation or premature closure of the growth plate medially, documented among more than 120 solitary bone cysts reviewed, was reason to undertake a thorough study of the growth plate in the area of the cyst. The findings in the hyaline zone disclose a considerable number of vessels and slits of the cartilage that are broadened toward the proliferative and hypertrophic zones. In some places they communicate with the vessels or are lined with endothelium. Ultrastructurally, changes of a destructive nature are disclosed, involving the growth plate zone and corresponding to the most active metabolic processes. In the altered chondrocytes substantial increases in glycogen granules and lipid droplets are observed, as well as reduction of the cellular organelles. In rather severely affected cells changes in the nuclei, lysosomal structures, and myelin-like lamellar bodies are established. The disappearance of cellular organelles and the fragmentation of cytoplasm are interpreted as a final phase of the above-listed changes. In conclusion, the cyst is considered a probable primary cause of the changes described.

Cilia in rat articular chondrocytes.

The cilia ultrastructural characteristics of chondrocytes from articular cartilage during its prenatal development were studied. It was established that these structures are not rare in electron microscopic observation of cartilage. They appear in the early stages of differentiation of the mesenchymal cells into chondroblasts. Ultrastructurally they show no differences during all periods of development. In some of the tangential layer cells of the newly formed articular cartilage were discover elements of more than one cillium in the same cell. It was also established that these structures project from parts of the cell presenting well developed Golgy complex.

Comparative assessment of articular cartilage and synovial membrane in experimental haemarthrosis.

The changes in articular cartilage and synovial membrane of the knee joints were studied in two groups of rabbits and Wistar rats with experimental haemarthrosis, electron microscopically. Hamarthrosis was produced in group 1 by a single autologous blood injection, in group 2 by intraarticular fracture of the femoral condyles. Samples were taken from the intact articular cartilage, the menisci and the infrapatellar portion of the synovial membrane 12 h to 20 days after intervention. Blood resorption occurs only in the synovial membrane. Fragmentation of erythrocytes and erythrocytophagy by synovial macrophages is documented. The different stages of intracellular digestion of erythrocyte fragments are traced down. Synovial fibroblasts do not participate in erythrocytophagy, although they disclose morphological signs of enhanced functional activity. The findings show changes in the matrix and chondrocytes within the articular cartilage and menisci, and presence of free erythrocytes and lipoprotein complexes amidst the collagen fibres of the matrix. The chondrocytes are poor in cell organelles, while the intracytoplasmic filaments, lipid droplets and glycogen granules are augmented in number. There is no evidence of erythrocytophagy by cartilage cells. On single blood injection in the joint, the ensuing changes are reversible, and the normal synovial membrane structure is restored much quicker than the articular cartilage.