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Biomedical subjects

N Vidinov

Publications and source records attributed to N Vidinov.

10 recordsLinked to original sources
PubMed2005

[Alterations in the structure of the epiretinal membranes in PVR -- assumptions and reality].

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.

Cell Death↗
PubMed2002

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.

Animals↗
PubMed1992

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.

Animals↗
PubMed1990

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.

Animals↗
PubMed1990

[Changes in the articular and growth cartilage of young rats after the intra-articular injection of hydrocortisone].

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.

Animals↗
PubMed1987

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.

Adolescent↗
PubMed1985

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.

Animals↗