Biomedical subjects

O V Antonova

Publications and source records attributed to O V Antonova.

12 recordsLinked to original sources

PubMed2003

[Local senile ocular amyloidosis in the pathogenesis of open-angle glaucoma and pseudo-exfoliative syndrome].

A total of 173 biopsy samples of the iris and drainage apparatus obtained at anti-glaucoma operations from 115 patients, aged 32 to 90, with primary open-angle glaucoma and pseudoexfoliative syndrome of different severity degrees were morphologically examined. Similar anatomofunction embryological peculiarities of the eye and brain create prerequisites for the development, in the eye, of processes analogical to Alzheimer's disease. Amyloid angiopathy of the iris is a key element of ischemia, which triggers the mechanisms of apoptosis and lipid peroxidation in the pigment epithelium membranes; this process is accompanied by an intensified synthesis and conformation of fibrous structures of tauprotein and beta-amyloid. Defradation of melanin and proteoglycans leads to the formation of neurotoxic metabolites. The above processes result in suppressing the protective antioxidant reactions as well as in blocking, by fibrous structures, the cellular cytoplasm and extracellular matrix.

Adult↗

PubMed1984

[Erythrocyte membranes during malignant growth].

Suspensions of red cells from normal subjects and cancer patients were incubated in the presence of hydrogen peroxide. The incubation gave rise to a flash of chemiluminescence including rapid and slow components. The concentration dependencies of chemiluminescence were plotted as was the dependence of chemiluminescence on the temperature of the suspension under test. The differences were found between chemiluminescence of donors' red cells and that of patients'. It is inferred that red cell membranes of cancer patients show both the decreased membrane resistance to the damage-inducing action of hydrogen peroxide and elevation of antioxidant activity.

Erythrocyte Membrane↗

PubMedDate not supplied

[Cell-to-cell interactions between iris and trabecular meshwork in primary open-angle glaucoma].

Pathomorphological study of the ocular draining system in the presence of an ischemic iris was carried out in patients with primary open-angle glaucoma (POAG). A total of 173 biopsy specimens of the sclera and iris were collected during anti-glaucoma operations in 115 patients aged 32-90 years. The specimens were stained for amyloid with Congo red, thioflavin, and toluidine blue at pH 4.6 and 5.8 for detecting glycosaminoglycanes. The specimens were examined by histochemical and electron microscopic methods. Morphological changes in the trabecular system in POAG are due to abnormalities in the iridal microcirculatory bed. The status of the trabecular system during the initial and advanced stages of glaucoma depends on the severity of involvement of iridal arterioles, capillaries, and venules, modulating the biochemical processes in the anterior segment of the eye. Endotheliocyte and collagen matrix pathology and subsequent degradation of the trabecular system are closely related to dystrophic processes in the iris (release of plasma protein from the vessels and melanin granules into anterior chamber humor, cytotoxic effects of degradation products on adjacent tissues). The detected changes imply the use of drugs improving blood supply to the eye at the microcirculatory level and antihypoxants and antioxidants in local and total-systems therapy of patients with POAG.

Adult↗

PubMedDate not supplied

[The causes of necrobiosis and apoptosis of corneal epithelial cells during primary acquired keratoconus].

We studied 56 biopsy samples of conjunctiva and 50 corneal discs excised from 28 patients with acquired keratoconus cornea. The conjunctivas in all biopsy samples showed various stages of immune inflammation. Necrobiotic changes have been revealed in epithelium of the corneal discs going by the pathways of apoptosis--programmed cell death--and oncosis--initial edematic stage of necrobiosis. At the stage of acute inflammation they are due to cytotoxic effect of the lymphocytes, monocytes, and macrophages. Antibody-dependent cytotoxicity mediated by plasma and lymphoid cells predominates at this stage. At the reparative stage of inflammation ischemia, an inductor of apoptosis and oncosis, underlies necrobiotic changes in corneal epithelium.

Adolescent↗

PubMedDate not supplied

[Lipid peroxidation in the pathogenesis of primary open-angle glaucoma].

19 tissue samplings of the iris and trabecula from 17 patients, aged 49 to 79, with primary open-angle glaucoma (POAG) of different stages were examined for the purpose of studying the condition of lipid membranes in the iridial and trabecular tissues by electron microscopy. The results are indicative of that the key role, in the POAG pathogenesis, belongs to lipid peroxidation of posterior and anterior leaves of the retinal pigment epithelium, which is an activator of apoptotic processes in the trabecular endothelium. Therefore, it is advisable to use the lipid- and water-soluble antioxidative drugs to correct the physiological antioxidative deficiency within a complex POAG treatment.

Adult↗

PubMedDate not supplied

[The characteristics of the nucleolar organizer in tumors of the choroid of the eye].

26 intraocular melanomas were studied histologically, ultrastructurally and morphometrically. For the first time the impregnation method was used for visualization of the nucleolar organizer (NO) in the cells of eye tumors using silver salts on the deparaffined sections. The efficiency and reliability of this method in the determination of the degree of malignancy of intraocular melanomas are demonstrated. A correlation existed between long-term postoperative results and the nucleolar organizer index (NO number/number of nuclei). The method can be practiced in any pathohistologic laboratory.

Adult↗

PubMedDate not supplied

[Diagnostic biopsy of the conjunctiva in keratoconus].

Morphologic examinations of biopsy specimens of the conjunctiva from 28 patients with keratoconus (56 biopsy specimens) revealed two types of pathologic processes: (1) acute and chronic immune inflammations of cell-mediated and mixed type (in 9 patients) and (2) fibrosis and acellular sclerosis as the result of the inflammation with the reduction of the microcirculatory bed and ischemia (19 patients). These data indicate the necessity of a differentiated approach to pre- and postoperative drug therapy of patients with keratoconus, exposed to perforating keratoplasty. The clinical picture does not permit a differentiation between types and phases of the inflammation for objective individualized prescription of drug therapy before and after perforating keratoplasty, therefore conjunctival biopsy is advisable in such cases as a diagnostic test. Histologic analysis gives data on the migration and proliferation of inflammatory cells, on the production of the intercellular substance, on the microcirculatory status. The results of this study helped the authors suggest a schematic approach to conservative therapy of patients suffering from keratoconus, aimed at inhibition of the inflammation.

Acute Disease↗

PubMedDate not supplied

[Amyloidosis of the iris and sclera in the pathogenesis of glaucoma].

Morphological analysis of 173 biopsies of the iris and sclera removed during antiglaucoma operations in 115 patients with open angle glaucoma showed extracellular deposits of amyloid in 44.4% of cases, which complicated the course of glaucomatous process and had pathogenetic importance. Amyloid was identified by Congo red [correction of Congo-rot] staining with the control in the polarized light and also by toluidine blue staining for chondroitin and dermatan sulfates. The vascular and muscle (pupillary muscle) forms of amyloidosis were found in the iris and the pericollagen and focal forms in the drainage system and sclera. We propose to classify the amyloid form of glaucoma with specific morphological picture.

Adult↗

PubMedDate not supplied

[Morphological features of senile and secondary amyloidosis of the iris and sclera in patients with glaucoma].

Morphologic analysis of 173 biopsy specimens of the iris and sclera removed during antiglaucoma surgery in 115 patients with open-angle glaucoma revealed in 44.4% cases extracellular depositions of amyloid, which aggravated the course of glaucomatous process and were pathogenetically significant. Amyloidosis was revealed in the sclera in 82% cases and in the iris in 70%. Amyloid was detected by Congo red staining with control in polarized light and by toluidine blue staining for chondroitin and dermatan sulfates. Vascular and muscular (involving the pupil muscles) forms of amyloidosis were detected in the iris, pericollagen and focal forms in the draining system and sclera. The authors discuss the contribution of amyloidosis to the pathogenesis of glaucoma. These findings confirm M.M. Krasnov's concept about glaucoma polymorphism.

Adult↗

PubMedDate not supplied

[The cellular aspects of amyloid angiopathies of the iris in open-angle glaucoma].

We studied cellular aspects of amyloid angiopathy of the iris upon decompensation of ocular pressure and the role of microcirculatory pathology in pathogenesis of the open angle glaucoma. A total of 115 iris biopsies were studied, which were taken during antiglaucoma operations and stained by Congo rot and thioflavine for amyloid and Toluidine blue for glycosaminoglycans. The biopsies from nine patients were studied at the ultrastructural level. Intravasal increase of the concentration of preamyloid proteins during spasms of the arterioles and capillaries should be considered as a provoking moment of the iris amyloidogenesis. Blockade of reticular structures of the microcirculatory basal membranes by preamyloid serum proteins, which provides for shedding of amyloid fibrils, dystrophic changes and detachment of the endothelial cells from the basal membrane, obliteration of lumens of the capillaries and arterioles, disturbed integrity of the microvascular barrier and accumulation of preamyloid and amyloid proteins in the extracellular matrix, ischemia and focal microinfarctions of the iris, and dystrophia of the melanocytes, are subsequent key factors. Amyloid angiopathy of the iris is a cause of ischemia of the anterior eye part, thus creating conditions for increased intraocular pressure and glaucoma.

Amyloid↗

PubMedDate not supplied

[Morphogenesis of corneal epithelial-endothelial dystrophy (a comparative morphological analysis of corneal disks and biopsy specimens of the conjunctiva)].

The aim of this study was morphological analysis of corneal disks and conjunctival biopsy specimens in order to disclose the mechanisms of development of epithelial-endothelial dystrophy (EED) and validating pathogenetically-based therapy. Twenty-five patients were observed, 11 of these with implanted intraocular lenses of different localization. EED developed for 1 to 5 years. Sixteen biopsy specimens of the conjunctiva and 21 corneal disks were examined. The composition and index of inflammatory infiltrate, status and compactness of conjunctival vessels, severity of fibrosis, and mast cell degranulation were assessed. Mast cells play a positive role at the initial stages of tissue and cellular response to injury by regulating the formation of extracellular matrix and fibroblast proliferation. At the reparative stages of immune inflammation of the conjunctiva, mast cells are virtually the only cell population; fibrosis and sclerosis develop when the capillary bed is reduced, causing ischemic involvement of the anterior segment of the eye and dystrophic processes in the cornea. A differentiated approach to treatment of EED at the stages of immune inflammation and fibrosis is emphasized.

Biopsy↗

PubMedDate not supplied

[The role of the mast cells of the conjunctiva in the intercellular interactions in keratoconus and epithelial-endothelial corneal dystrophy].

The aim of this study was assessment of the role of mast cells in inflammatory processes associated with keratoconus and corneal epithelial-endothelial dystrophy and clinical assessment of Lecrolin, a specially designed dosage form (eye drops) of potassium cromoglycate (intal) used as an antiallergic drug in asthma, rhinitis, etc. Examinations of 43 biopsy specimens of the conjunctiva from patients with keratoconus and epithelial-endothelial corneal dystrophy demonstrated the significance of immune inflammation in the pathogenesis of these diseases. Mast cells are a typical cell element participating in inflammation at all stages. The count of mast cells increases from 2.5 during the acute stage to 8.86 during the chronic stage, which is explained by absence of the leukocytic stage and proteolysis and stabilization of mature labrocyte degranulation associated with it. Reactions of mast cells with lymphocytes and monocytes/macrophages lead to proliferation of fibroblasts and chronic development of collagen formation. Close relationships between microvessels and mast cells promote stable spasms of the vessels, impairing the microcirculatory bed and leading to ischemia of the anterior segment of the eye. In such cases sodium cromolyne drugs (lecrolin) inhibiting histamine release and stabilizing mast cell membranes are recommended.

Biopsy↗