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Biomedical subjects

A B Shekhter

Publications and source records attributed to A B Shekhter.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

[Effects of gaseous flow containing nitric oxide on the eyeball structures (an experimental study)].

Nitric oxide is one of the main factors of intra- and intercellular regulation in the organism. Its vasodilating, antiaggregant, antithrombogenic, antibacterial, anticarcinogenic, and immunogenic effects are well known. It stimulates the reparative processes in soft tissue injuries. We failed to find reports about the role of NO in the wound process in the eyes. The source of NO in our experiments was medical air-plasma device Plason. Exposure of the eye to NO-containing gaseous flow did not cause changes in the lacrimal pH; NO penetrated through the cornea and sclera, exerted no appreciable cytotoxic effect on the surface epithelium of the eye, did not change the intraocular pressure, and caused no morphological changes in ocular tissues. On the other hand, NO-containing gaseous flow had an appreciable lasting effect on the diameter of the conjunctival vessels, this effect being dose-dependent. The doses of NO-containing gaseous flow which can be used in the treatment of eye wounds were determined.

Animals↗
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[The morphofunctional characteristics of the dystrophic and reparative processes in experimental autodermoplasty using a CO2 laser].

The aim of this work was research of the morphofunctional features of rabbit free skin flaps after CO2 laser and scalpel interventions. pO2, histologic and histochemical data were analyzed. The results evidence an insignificant delay of the pO2 growth in laser-treated flaps early after surgery. This fact hints at a low speed of laser-treated flaps vascularization because of wound coagulation necrosis. However, this does not influence the course of the reparative process. Our conclusions are confirmed by histologic and histochemical findings.

Animals↗
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[A comparative study of the effects of laser and light-emitting diode irradiation on the wound healing and functional activity of wound exudate leukocytes].

The effects of coherent He-Ne laser and non-coherent light-emitting diode radiation on rat skin wound healing and functional activity of wound excudate leukocytes were compared. A comparative pathomorphological analysis showed that the He-Ne laser and light-emitting diode irradiation stimulated the transition of the inflammatory phase of the wound healing into the reparative (proliferative) and scarring phases sequentially. It was also detected that the functional activity of leucocytes changed in a dose-dependent manner. The leukocyte activity was found to be similar in the groups with laser and light-emitting diode irradiation. Thus, we can conclude that coherent laser and non-coherent light-emitting diode radiation have very close effects on wound healing and activity of wound exudate leukocytes, and coherence is not required for this activity.

Animals↗
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[Synthesis of nucleic acids and dynamics of morphological indices of the granulation tissue of skin wounds in rats treated with 4-methyluracil].

Effect of 4-methyl uracil on dynamics of morphological patterns and the rate of nucleic acids synthesis was studied in granulation tissue developed during healing of full-layer skin wounds. Application of ointment containing 4-methyl uracil onto the wounds exhibited an antiinflammatory efficiency and decreased accumulation of leukocytes in the wound. The drug shortened the mitotic cycle in dividing fibroblasts, as a result of which periods of DNA synthesis became more frequent exhibiting two days duration. The rate of RNA synthesis was increased 1.5-2-fold. Content of acid glycosaminoglycans and collagen was increased in intercellular space surrounding fibroblasts.

Animals↗
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[Histomorphology and histochemistry of acquired scars of the laryngo-tracheal regions in children].

Acquired scars of the tracheolaryngeal compartment dissected during surgery of 28 children (35 samples) were taken under histological and histochemical examination. In most cases, scar tissues-showed signs of chronic inflammatory infiltration, pronounced changes of the microcirculatory bed, dystrophic and destructive processes, continuous formation of granulation foci and subsequent fibrosis, fibrotic changes in muscles and noticeable dystrophic and metaplastic changes of the epithelium. This points to changes in the relationship between inflammation and regeneration and persistence of inflammatory, sclerotic and dysplastic processes which may cause recurrent development of stenotic scars after their removal.

Adolescent↗
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[Morphofunctional parallels in the dynamics of the take of an experimental free skin autograft].

Free skin autotransplantation may be adequately simulated in albino chinchilla rabbits. Gradual elevation of tc PO2 in the transplanted graft is considered as a functional indicator of the time course of autodermotransplant taking in. Morphologic study has shown dystrophic changes in the graft surface layers in the early periods of healing during scab formation, because of inadequate nutrition of the flap. Later the proliferative processes activate, the vessels on the side of the graft bed grow in, the scab is rejected, and the graft surface epithelializes. The time course of circulation and structure of the graft recovery is in line with the oxygen regimen time course.

Animals↗
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[A comparative evaluation of the efficacy and tolerance of gold and D-penicillamine preparations in patients with rheumatoid arthritis. II. The effect on the morphological indices of rheumatoid synovitis].

Morphological signs of rheumatoid synovitis have been analysed on the basis of 130 puncture biopsies taken from 46 patients prior to the beginning and during parenteral therapy with auric preparations (crysanolom and myocrysin) and peroral administration of an auric preparation rhidaura and small doses of D-penicillamine. The most marked morphological effect was reached in 1.5 years. With a favourable clinical effect all the preparations exhibited capacity for suppressing the following basic signs of rheumatoid synovitis: proliferative changes in the layer of synoviocytes, reaction of blast cells.

Adult↗
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[Roentgeno-morphological comparisons in rheumatoid arthritis based on data of a long-term prospective study].

During a prospective observation lasting 6 years 68 patients with rheumatic arthritis (RA) were repeatedly examined (up to 8 times) roentgenologically with parallel puncture biopsy of the synovial fluid of the knee joint made with an atraumatic needle, and numerical evaluation of markedness of 25 morphological signs of synovitis. A comparative analysis of the markedness of morphological signs of synovitis in relation to the degree and dynamics of destructive changes in the knee joint was made on the basis of the findings of 254 puncture biopsies and the same amount of roentgenograms. There is a close relationship between the activity of synovitis and the progress of destructive arthritis except for the morphological signs characterizing the reaction of hypersensitivity of an immediate type that may serve the purpose of prognostication of further articular destruction and of the choice of an early adequate therapy.

Adult↗
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[Fibril formation in solutions of solubilized collagen].

Influence of the preparations of bacterial proteinases, protorisine and prototerrisine, was studied on the stability of the mature collagen of beef skin. The chemical composition of the tissue has been shown to be changed by these enzymes inconsiderably. The tissue treated by orisine and terrisine is completely dissolved in 0.5 M acetic acid (solubilized collagen). When the solutions of such collagen are heated to 37 degrees within the pH range from 4 to 10 at the ionic strength of 0.25 fibrils are formed. Under electron microscope fibres are cross-striated that is typical of native collagen fibres with periodicity of about 640 A. After chilling to 4 degrees, a part of fibrils is dissolved again. Nephlometry was used to study the rate of fibril formation as a function of pH and temperature values. A conclusion has been drawn that the mature collagne dissolved after incubation with bacterial proteinases is close to the acid-soluble collagen fraction in the ability to produce fibres upon heating.

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[Dynamics of nucleic acid synthesis in the granulation tissue of skin wounds in the rat].

Dynamics of nucleic acid synthesis was studied in granulation tissue, harvested within 2-11 days after an injury of rats with full-layer skin wounds, simultaneously with evaluation of the morphometric patterns of the tissue. Synthesis of nuclear DNA exhibited a wave-shaped dynamics. The intervals between the maximal values of the DNA synthesis constituted 3 days. Within the early steps of wound healing the intensive incorporation of 3H-thymidine into mitochondrial DNA was found, which appears to occur due to active mitochondriogenesis. In dynamics of total and nuclear RNA contents two peaks were observed, which did not coincide in time, thus suggesting the wave-shaped increase in biosynthetic processes in cells.

Animals↗
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[Stimulation of DNA and RNA synthesis in the liver of hepatectomized rats by fractions of liver cytosol and conditioned media obtained during cultivation of rat liver explants].

Heat resistant fractions stimulating proliferation (PSF) were identified in the fractions of rat liver cytosol after 70% hepatectomy as well as in the medium harvested after cultivation of rat liver explants. The PSF augmented considerably the rate of DNA synthesis, it increased synthesis and transport of rapidly labelled RNA as well as the level of mitotic activity in rat liver tissue resected by 30% and 80%. Role of the PSF in regulation and acceleration of regeneration processes in the residual parts of liver tissue, remained after hepatectomy, is discussed.

Animals↗
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[The importance of arthroscopy and guided biopsy of the knee joint in gout].

The authors studied the arthroscopic picture of the knee joint in 50 male patients, 40 of whom had a genuine gout and 10 a doubtful one. A high diagnostic significance of arthroscopy was emphasized, it rose with the use of a morphological analysis of samples of synovial membrane and villi obtained by means of target biopsy, microscopy and chemical identification of urate.

Adult↗