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Biomedical subjects

M V Zueva

Publications and source records attributed to M V Zueva.

At least 19 recordsLinked to original sources
PubMed2003

[Electroretinography in the diagnosis and study of pathogenesis of X-linkage retinoschizis].

Due to an extensive variability of manifestations of X-linkage retinoschizis, there is a need in a differential diagnosis of it and of other hereditary retinal diseases. The method of electroretinography is often of primary importance in specifying a diagnosis in ophthalmology; it both enables the detection of new and more sensitive criteria of early and differential diagnosis and ensures a more profound understanding of changes occurring in the retina. A topical analysis of changes of the bioelectric activity taking place in different retinal layers and sections as well as a differential evaluation of the functional condition of neurons and glia Muller's cells in patients with X-linkage retinoschizis were accomplished within the framework of this study. The nature of the peak latency and of the b-wave amplitude in the electroretinogram (ERG) and in the mechano-electroretinogram (MERG) as well as of a low-frequency ERG is indicative of that Muller's cells are damaged; the damage severity is related with an intensity of the pathological process and can be objectively determined by the ERG examinations of patients. An analysis of sub-components of a low-frequency rheoelectroretinogram (RERG) shows weakened inhibitory inter-neuron connections in the retina, which is a sign of disease aggravation. The regularities of changes of retinal biopotential to blue light flashes under all registration conditions (ganz-feld, macular and rhythmical stimulation) differ from the ERG dynamics to other light stimuli, which is indicative of a significant role of the pathology of S-cone paths in the development of X-linkage retinoschizis.

Adolescent↗
PubMed1990

[The rhythmic ERG in the diagnosis of diabetic retinopathy in cataract patients].

The paper describes a new method for diagnosing initial stages of diabetic retinopathy in the presence of cataract--analysis of amplitude parameters of averaged ERG. The usage of different frequency stimuli allows to separately judge about the state of peripheral (10 Hz) and central (40 Hz) segments of the retina. The stage of diabetic retinopathy can be judged by degree of depression of rhythmical ERG. Ophthalmoscopic and fluorescein angiographic verification of the method conducted in 70 patients (94 eyes) after cataract extraction confirmed its high informativeness.

Aged↗
PubMed1983

Ultrastructural alterations in rat and cat retina and pigment epithelium induced by chloroquine.

Chloroquine retinopathy in rats and cats was studied (in long-term experiments on rats the drug was injected into the stomach). We observed the slow development of the pathological process, accompanied by the appearance of membrane inclusions in GC, structural alterations in the RPE, and after 10 months complete destruction of the outer segments of the photoreceptors. In experiments on cats, after a single intravitreous chloroquine injection destruction of the photoreceptors, similar to that observed in rats, was found 2 weeks after the injection. In the region of tapetum nigrum containing melanin photoreceptors were safe. These data suggest the protective effect of melanin on the process of chloroquine retinopathy.

Animals↗
PubMed1983

Change of histochemical and electrophysiological values of rabbit retina due to the antihypoxant sodium hydroxybutyrate.

This paper presents the results of an electrophysiologic and histochemical study on the effect of sodium hydroxybutyrate applied perorally as 5% syrup for 20 days on the rabbit retina. It was found with statistical significance that in response to the drug the amplitudes of "a" and "b" waves of the electroretinogram increased considerably and the activation of some dehydrogenases, glucose-6-phosphatedehydrogenase and lactatedehydrogenase in particular took place; this was most pronounced in the ganglion and in the inner nuclear layers of the retina. The results of the study show that a prolonged peroral application of 5% sodium hydroxybutyrate syrup might be an expeditious way to activate energy processes in the retina.

Animals↗
PubMedDate not supplied

[Time course of bioelectrical activity of retina in patients with pigmented abiotrophy treated by deoxinate].

Bioelectrical retinal activity was assessed before and after a course of deoxinate therapy and in a blind placebo test in order to assess the efficacy of this new drug in the treatment of patients with pigmented retinal abiotrophy. Time course of electroretinograms during deoxinate therapy indicated a significant positive effect of the drug on retinal function as regards a variety of electrophysiological parameters in 80-94% patients. Improvement of electroretinography data was paralleled by improvement of visual acuity, extension of visual fields, and decrease of scotomas. Good effect was attained in patients with early and far advanced stages of pigmented retinal abiotrophy. Analysis of bioelectrical activity of the retina after a course of therapy with deoxinate and enkad showed a higher efficacy of the former drug in patients with pigmented retinal abiotrophy.

Adjuvants, Immunologic↗
PubMedDate not supplied

Electroretinographic characteristics of proliferative vitreoretinopathy in rhegmatogenous detachment of retina.

Thirty-five patients with types A, B, C2, C3, and D1 proliferative vitreoretinopathy (PVR) were followed up for 8-14 months after surgical treatment of rhegmatogenic amotio retinae. Hanz-Feld electroretinogram (ERG), rhythmic ERG to low and high-frequency stimulation, and macular ERG were recorded. Before surgery all patients presented with specific signs of changes in the retinal electrogenesis, characteristic of rhegmatogenic amotio retinae with PVR of different types. Comparative analysis of ERG and rhythmic ERG alteration showed a more expressed reaction of Mueller's glial cells in patients with types A-C2 PVR and of second order neurons in the internal nuclear layer of the retina in those with types C3 and D1 PVR. Characteristic changes in the retinal functional activity were detected, possessing a prognostic significance. According to electrophysiological studies, the decisive factor for predicting the course of recovery after surgical treatment of retinal detachment is the preoperative function of retinal neurons. A drastic depression of low-frequency rhythmic ERG is the most unfavorable sign in prognosis of the postoperative time course of visual functions. The least favorable course of recovery after the operation is typical of amotio retinae with type C3 PVR. Recovery of amplitudes of different biopotentials and functional horizontal bonds at different levels of the retinal structure is different.

Electroretinography↗
PubMedDate not supplied

[Early changes in the bioelectrical activity of retina after eyeball contusion].

Characteristic signs of changes in the bioelectrical activity of the retina soon after contusion of the eyeball supplement the functional criteria used for accurate diagnosis of the severity of contusion (classification of the injury). The most sensitive indicator of electroretinography is the amplitude of the electroretinogram (ERG) a-wave, which is sharply suppressed during the first three days in injury of any severity. Recovery of the bioelectrical activity of photoreceptors is delayed in comparison with the time course of the function of the second-order neurons (more rapid recovery of the b-wave in comparison with the a-wave). The reactivity of Müller cells increases in severe contusion, which is shown by a more pronounced decrease in the ERG b-wave amplitude and less expressed changes in low-frequency ERG. Analysis of the time course of biopotentials during repeated examinations of the patients helps control the efficacy of treatment. The results indicate that electroretinographic examinations are the most desirable 5-7 days after the contusion, because at this period the differences in the bioelectrical activity of the retina are the most expressed. The most informative parameters of electroretinography are the time course of total ERG a- and b-waves and the low-frequency rhythmic ERG.

Action Potentials↗
PubMedDate not supplied

[Effects of ozone therapy on the functional activity of the retina in patients with involutional central chorioretinal dystrophy].

The retinal electrogenesis was studied in central chorioretinal dystrophy (CCRD) of different stages. The general peculiarities of the ozone-therapy influence on the functional retinal activity typical of any CCRD stage were detected; they comprise: an increasing activity of neurons in the muscular region and a specificity related with the dynamic functional activity of the retinal peripheral segments peculiar of each disease stage. A sharp growth of glial index Cg (b/R12) detected in all patients is indicative of an activated metabolism of Mueller glial cells and of impaired glial-neuron relations in the retina as observed in CCRD. A decreasing Cg, observed after ozone-therapy, is an indirect confirmation of anti-hypoxic effect produced by ozone, which can be regarded as a patho-physiological mechanism of its positive influence on the dynamics of the functional retinal activity. Ozone-therapy is recommended to be implemented with the electroretinography monitoring.

Choroid Diseases↗
PubMedDate not supplied

[Evaluation of the consequences of stress factors on plant seeds growing in a 30-km zone of Balakovo AES].

The effect of stress factors (small doses of radiation and maximum temperatures in the econiche of the tested plants (tmax)) as well as aging on pea seeds, both acting independently and in combination, is estimated. Here we evaluate the influence of oxidizing stress on pea seeds in the laboratory (gamma-irradiated with 7 cGy at 0.3-19.1 cGy/h, tmax approximately 30-32 degrees C) and on natural plantain seeds collected in a 30-km zone of NPP (radiation exposure approximately 15 R/h, tmax approximately 38-40 degrees C). We have mathematically modeled CAs frequencies in root seedlings meristeme by invoking an enhancing factor transmitted from cell to cell. It is shown under the stress conditions: 1) CA frequency decreases whereas the fraction of inviable seeds (IS) increases, the dependence of IS on CA frequency being inversed; 2) a stimulation of proliferation of cell was observed; 3) a bystander effect appears; 4) antioxidative status (AOS) of seeds influences on adaptation on the all levels of the organization; 5) IS increases up to 73-80% under the combined effect of radiation and heat stresses.

Bystander Effect↗
PubMedDate not supplied

[Experimental intraocular introduction of blood serum of patients with endophthalmitis].

Effects of blood serum from patients with endophthalmitis, who systematically received gentamicin at therapeutic dose, exerted on the retina of healthy rabbits were experimentally studied. A moderate toxic effect produced by gentamicin on the retina, when it was administered in the vitreous body of rabbits, was detected yet on day 1 of the experiment. Changes of retinal electrogenesis were aggravating and, beginning from day 7, there were noted profound changes of the functional activity in all retinal layers. According to the results, the blood serum from patients with endophthalmitis, who were systematically receiving gantamicin at therapeutic dose, does not virtually have any negative effect on the functional condition of the retina and can be used for intracavitary administration.

Animals↗
PubMedDate not supplied

[Functional diagnosis of retinal ischemia. Communication 1. Reaction of Muller cells at early stages of diabetic retinopathy].

Electroretinographic examinations were made in 191 patients with non-proliferative and pre-proliferative diabetic retinopathy. On the basis of the ratio of b-wave in ??? and ???? at 12 Hz, the glial index (Cg) was estimated for evaluating the functional changes in Muller cells. As the retinal ischemia aggravated, C@f was increasing, which was indicative of an activated metabolism of Muller cells. C@g was shown to be a sensitive criterion of retinal ischemia ensuring the detection of initial stages of retinal ischemia prior to the detection of changes recognizable in ophthalmoscopy and fluorescence angiography. The established regularities of changing functions in Muller glia and in glia-neuron ratios denote the possibility of using the electroretinographic criteria in the diagnosis of lesions in the retina and of early signs of retinal dystrophy in diabetic retinopathy.

Adult↗
PubMedDate not supplied

[Transplantation of neural stem cells in experimental retinopathy].

A stable and easily reproducible model of experimental retinopathy was constructed in rabbits. The influence of transplanted neural stem cells (NSC) on the functional activity of the retina was studied. Retinopathy was provoked by 0.04 mg of kainic acid introduced intravitreously. The cultivated NSCs were transplanted into the vitreous bodies of the right (experimental) eyes, physiological solution was administered into the left (control) eyes. Clinical examinations of the eyeball in the experimental group showed less pronounced proliferative changes and a lack of gliosis, whereas, in the control group, the retina looked like tissue with fibrous changes and glial bars. An evaluation of the functional activity of the retina denoted a reliably better function of rod bipolars and Muller glias in the eyes with transplanted NSCs during the whole follow-up.

Animals↗
PubMedDate not supplied

[Functional diagnostics of retinal ischemia: Muller cells and neovascularization of the retina in diabetic retinopathy].

Electrography was made for 58 patients (110 eyes) with proliferative diabetic retinopathy distinguished by neovascularization. Fluorescence angiography and electroretinography were dynamically made for 1-1.5 years in 18 patients with preproliferative diabetic retinopathy. The hyperfunction of Muller cells with an increasing glial index, which was detected earlier by us in progressing retinal ischemia, was also observed in retinal neovascularization. The regular monitoring of the dynamics of electroretinogram (ERG, made several times) makes it possible to evaluate in each separate case a degree of neovascularization risk. When the value of the glial index abruptly drops in a patient, who had earlier regular increases in the index value, there is a high probability of a fast development of retinal neovascularization. Regular ERG examinations are advisable for the evaluation of a neovascularization risk.

Diabetic Retinopathy↗
PubMedDate not supplied

[Antibodies to retinal S antigen in the tear and serum as an indicator of the nature of a course of endogenous uveitis in children].

Antibodies (IgM and IgG) to retinal S antigen were studied by enzyme immunoassay in the tear (n = 135) and blood serum (n = 221) samples taken from 45 children with chronic endogenous uveitis during a follow-up (for 6 months to 5 years). The studies have confirmed the early evidence that detection of serum autoantibodies may be used for the diagnosis of autoimmune and infectious-and-autoimmune uveitis, the verification and prediction of renal alterations, risks for lesions in the second eye in unilateral uveitis and prerecurrence in bilateral uveitis. Criteria for detecting antibodies to lacrimal S antigen were developed. Its has been ascertained that it is expedient to use this procedure as a method for controlling the efficiency of treatment in uveitis involving the posterior parts of the eye, confirming, and predicting the risk for involvement of the retina into an inflammatory process, detecting trends for development of chronic forms of both bilateral and unilateral uveitis. Simultaneous accumulation of IgM and/or IgG antibodies in the lacrimal fluid and serum, as well as imbalance, i.e. a prolonged enhancement of only local or only systemic response to S antigen (of both classes), are prognostically unfavorable.

Adolescent↗