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Biomedical subjects

A B Shekhter

Publications and source records attributed to A B Shekhter.

At least 19 recordsLinked to original sources
PubMed1994

[Drug-induced remission in the severe progressive variant of rheumatoid arthritis].

Analysis of the remission incidence and duration has been made in 71 patients with severe progressive rheumatoid arthritis (RA) during the 10-20-year follow-up period, with special attention paid to the role of the disease-modifying drugs (DMARDs). Remission occurred only in those patients who received permanent long-term systematic treatment with DMARDs. Such a therapeutic approach resulted in remission lasting from 5 to 11 years for 32% of the patients. Otherwise the patients who received episodic non-regular DMARDs therapy or symptomatic treatment with nonsteroidal anti-inflammatory drugs or steroids had no remission at all. A detailed analysis of the cases of remission is presented. The authors are of the opinion that after the disappearance of the clinical signs of RA the maintenance basic therapy may be continued.

Adult↗
PubMed1992

[Effect of carnosine and 4-methyluracil on the development of experimental hepatitis in rats].

A comparative study of the hepatoprotective effect of carnosine and 4-methyluracil under CCl4-induced acute toxic hepatitis has been carried out. The extent of liver injury and its regeneration were established from morphological data as well as from changes in the activities of alanine aminotransferase (ALT) and histidase and the bilirubin content in blood serum. Hyperlipoperoxidation in the liver and serum was assessed by the amount of TBA-active products. It was found that by day 10 of experimental hepatitis ALT and histidase levels in blood sera of untreated animals exceeded the normal values 1.3- and 3.9-fold, whereas those in the carnosine-treated group approximated the values characteristic of intact animals. The activity of serum ALT in animals treated with vitamin B12 or 4-methyluracil exceeded normal values 1.5 and 1.6 times, whereas that of histidase was 2.5 and 2.7 times as high. Carnosine and 4-methyluracil inhibited (in approximately the same degree) the formation of TBA-active products in the liver. According to morphological dta, cessation of CCl4 injections was accompanied by rapid regeneration of liver tissues in all animal groups. Carnosine enhanced regenerative processes in parenchymatous and connective tissues in a far greater degree in comparison with other drugs. The mitotic index in the carnosine-treated group exceeded more than twofold the corresponding parameters in untreated animals. Possible mechanisms of carnosine action on liver repair are discussed.

Alanine Transaminase↗
PubMed1991

[The level of postvaccinal immunity to diphtheria, tetanus and poliomyelitis in relation to the number of inoculations].

The work was aimed at the comparative study of the intensity of immunity to diphtheria, tetanus and poliomyelitis, depending on the number of injections of adsorbed diphtheria-pertussis-tetanus (DPT) vaccine and poliomyelitis vaccine, for the purpose of finding out the possibility of reducing the antigenic load given to children without diminishing the intensity of immunity. To determine the level of immunity to diphtheria and tetanus, 1900 children under school age were serologically studied by the micromethod in the passive hemagglutination test. The intensity of immunity to poliomyelitis virus was studied in 333 children by means of the neutralization test. The immunogenic properties of the diphtheria component of adsorbed DPT vaccine were found to be less pronounced than those of the tetanus component of the vaccine, which made it impossible to reduce the antigenic load by decreasing the number of vaccinations against diphtheria. The results of the study of postvaccinal immunity to poliomyelitis suggest that during the first and second year of life the course of vaccination against poliomyelitis may be reduced to 3 injections.

Antibodies, Bacterial↗
PubMed1991

[Inflammation, adaptive regeneration and dysregeneration (intercellular interaction analysis)].

Inflammation, regeneration and fibrosis are inseparable components of the adaptive tissue response to damage. Systemic analysis indicates that this reaction is brought about due to the cooperative interaction of the connective tissue and blood cells (neutrophils, labrocytes, thrombocytes, macrophages, lymphocytes, fibroblasts) between each other, with intercellular matrix (collagen, fibronectin, proteoglycans) and organ parenchyma on the basis of feedback mechanisms. The role of the "cell orchestra conductor" changes at different stage of reaction; macrophage-fibroblast interaction is the most important in the cooperation between inflammation and regeneration. The breakdown of the homeostatic autoregulatory mechanisms (particularly those of intercellular and intertissue interaction) results in the disturbance of standard reactions, disintegration of inflammation and regeneration, chronicity of inflammatory reactions, incomplete regeneration, progressing sclerosis, formation of deficient granulation and fibrous tissue, tendency to the secondary destruction. The process loses the adaptive character and the notion of "dysregeneration" is introduced for its characteristics.

Adaptation, Physiological↗
PubMed1991

[Disorders of oxidizing metabolism as a criterion of evaluation of the course of wound healing in experimental animals].

The authors carried out 90 experiments in fertile male Wistar rats and 10 experiments in rabbits with noncomplicated and complicated (infectious) wounds. We have revealed in the first 24 hours the characteristic changes of pro- and antioxidation potentials and acid-alkaline condition of blood plasma. The increasing of specific activity of LPO product by 30-40% and the decreasing of hydroperoxides level in comparison with the initial levels of these indicators and the decreasing of blood pH point out the possibility of purulent inflammation development in postoperative wounds. We can use the special treatment of purulent inflammatory wounds in early stages of its development by the meaning of prognostication of wound healing that is very valuable in medical practice.

Animals↗
PubMed1989

[Characteristics of the course of the wound process in spontaneously hypertensive rats and the effect of morphine, substance P and its fragment SP1-4].

The paper demonstrates that in spontaneously hypertensive rats (SHR) as compared with normotensive controls exudative processes at the sites of lesions are much more prominent. Such exudative processes include edema, fibrinous exudation as well as permeability of capillaries and venular walls for leukocytes. These effects prolong the phase of its inflammation and retard the regeneration phase in wound healing. Morphine and SP1-11 stimulate in a similar fashion repair during wound healing in the both rat strains. Their effect is similar to the effect of opioid peptides. SP1-4 does not affect vessel reactivity and wound healing in SHR, which is related to disturbed expression of receptors to SP fragments. Synergism in the effect of two functional antagonists i.e. opioids and SP on wound healing confirms our hypothesis about the role of pain as an inducer of a variety of mechanisms underlying repair regeneration.

Animals↗
PubMed1989

[Fibrinoid and fibrinoid necrosis in the morphogenesis of chronic stomach ulcers (electron and light microscopy)].

The stomach surgically removed from 38 patients because of chronic ulcers are studied. The fibrinoid necrosis zone observed at the bottom of 30 ulcers is formed of two layers out of which the superficial layer only is necrotic while the deep one represent a fibrinoid swelling. The latter consists of the network of collagen fibers and fibrin elements with surviving connective tissue cells. Two processes going into the opposite directions take place on the border between the fibrinoid zone and granulation tissue: the spread of the fibrinoid to the granulation tissue and its organization by the granulation tissue elements. Interrelationship between these processes as well as the intensity of the fibrinoid necrosis rejection from the surface determines the thickness of the zone. Fibrinoid prevents the stomach wall digestion but at the same time inhibits the ulcer healing.

Adult↗
PubMed1989

[The interrelationship between serotonin and lipid peroxidation products during experimental wound healing].

On 220 male Wistar rats with models of aseptic and contaminated skin wounds the authors studied interrelationship between serotonin and hydroperoxide in the wound tissues and the blood. A comparative analysis of the changes of these indices in the blood and tissues showed that the degree of these disorders on the 1st day after the operation was determined by operational trauma and with the development of purulent inflammation intensive initiation of lipoperoxidation products takes place.

Animals↗
PubMed1989

[Studies and clinical experiences in the use of domestic blood vessel prostheses with increased thromboresistance].

The experimental and clinical data on the use of new native grafts with increased thromboresistance--the Vitlan and heparinized ones are presented. In all the acute and chronic experiments, the increased thromboresistance of both types of the grafts versus the common Fluorlon-Lavsan ones, and well-formed neointima with sufficient vascularization by the year 1 and 5 of follow-up were revealed. Complete organization of the external and internal capsules of the grafts was noted 5 mos later, no tissue reaction to Vitlan and heparinized grafts was revealed. The Vitlan grafts were used in 19 patients. Good immediate and long-term results were obtained in reconstruction of the aorto-femoral, aorto-pulmonary and femoro-popliteal segments with the grafts of 10 and 8 mm in diameter. All the Vitlan shunts of the femoro-popliteal segment with 6 mm diameter were thrombosed 1-6 mos after the operation. The heparinized grafts with 8 mm diameter at the femoro-popliteal position were used in 28 patients, good long-term results were noted in 27.

Animals↗
PubMed1988

[Ascorbic acid and hydroxyproline levels in the serum and granulation tissue of rats with aseptic and infected wounds].

Hydroxyproline and ascorbic acid were measured in wound tissues and ascorbic acid was determined in the blood sera of 230 mature male Wistar rats with aseptic and infected surface wounds on days 1-10 (daily), 12, and 15. The principal morphologic characteristics of the granulation tissue were assessed by semiquantitative methods. An infected wound is characterized by increased hydroxyproline levels in the granulation tissue and elevated ascorbic acid concentration in the blood serum. The granulation tissue ascorbic acid level augments during the first nine days in case of an aseptic wound and during twelve days in case of an infected wound. Morphologic and biochemical correlations are indicative of a relationship between the ascorbic acid level on the one hand and granulation tissue vascularization and fibroblast proliferation on the other.

Animals↗
PubMed1988

[Effects of opioid peptide dalargin on reparative processes in wound healing].

At intraperitoneal injection and local application of opioid peptide dalargin induces fibroblast proliferation (3-fold increase in the mitotic index) and growth of capillaries, accelerates the maturation of granulation tissue and of scar, epitheliazation of the defect, and considerably reduces the period of healing of skin wound in rats. The stimulating action of dalargin is associated with its effect on the microcirculation system and activation of the macrophage-fibroblast interaction. Possessing the triggering mechanism, the drug induces a cascade of inflammatory-reparative reactions, which reduce the duration of all healing stages.

Administration, Topical↗
PubMed1988

[A calendar of prophylactic inoculations in wide practical use].

The validity of immunizations, made in due time in children aged up to 7 years in accordance with the approved immunization schedule, is analyzed in this work. The content of antibodies to diphtheria, tetanus and poliomyelitis antigens in children immunized in accordance with the old and new schedules has been studied. This study has revealed that the injection of adsorbed DPT vaccine to children aged 3-4 months induces fully valid immune response to all antigens under study. The level of measles and parotitis antibodies after the injections of measles and parotitis vaccines, introduced separately and simultaneously, has been measured. The simultaneous administration of these preparations did not decrease the levels of immunity to parotitis and measles.

Antibody Formation↗
PubMed1988

[Method of creating a model for assessing the effectiveness of preparing the wound surface for autodermoplasty in an experiment].

Twenty rabbits and fourty male rats were used for the development of the autodermoplasty model: two symmetrical semilunar skin incisions, turned to one another, with 1 cm space between the ends of the arches, were made on the back of the animal. The skin with subcutaneous fat was exfoliated from above the muscular tissue in the area between the incisions. Elastic arched net-shaped fluoroplastic plate, matching to the size of the exfoliated skin graft and raising it 1.5 cm above the wound surface was introduced into the cavity emerged. As soon as any method of wound surface purification was used, the plate was removed and the the skin graft above (conditional autodermograft) was applied and fixed to the edges of the wound with 4 interrupted sutures. It was stated that the model used for testing various methods of preparing the wound surface for autodermoplasty not only decreased the duration of experiment and the number of animals employed but cut their keeping and dressing expenditures.

Animals↗
PubMed1987

[Cytophotometric study of blood neutrophil and wound exudate myeloperoxidase in experimental wound healing].

Changes in the activity of blood neutrophil and wound exudate myeloperoxidase (MP) have been studied cytophotometrically on the models of aseptic and infected experimental wounds in 220 male Wistar rats on the 1st-10th, 12th and 15th day after wounding. It has been established that changes in MP activity reflect the nature and stages of the pathological process and the animals' reaction to it. MP activity is significantly higher in animals with infected wounds, which indicates the intensity and duration of the inflammatory process and is of prognostic value.

Animals↗
PubMed1987

[Phosphatase activity of blood leukocytes and wound exudate during the experimental healing of an aseptic wound].

Cytochemical investigations of plain aseptic wounds simulated in 110 Wistar rats revealed a clear-cut dependence between the variations in the activity of alkaline and acid phosphatases in neutrophilic leukocytes, monocytes and lymphocytes of the blood and wound exudate and the stage of the healing process. Elevated activity of the blood alkaline phosphatase correlated with the term of inflammation phase.

Acid Phosphatase↗
PubMed1986

Connective tissue as an integral system: role of cell-cell and cell-matrix interactions.

We have applied the systems approach, to the analysis of mechanisms whereby connective tissue (CT) is integrated into one functional system. The primary CT functions in health and in disease (biomechanical, trophic, protective, reparative, and morphogenetic) are carried out by means of cell-cell, cell-matrix and intertissue interactions based on feedback between these components. Both CT as a whole and its cellular and extracellular elements exhibit structural and functional heterogeneity which increases the capacity of CT for adaptation. The intercellular interactions take place via soluble and insoluble mediators, direct cellular contacts, and cell/matrix degradation products. Results of this study support the concept of internal "network" regulation of the CT composition, functions and growth through intercellular interactions at different structural levels. Feedback mechanisms between degradation and production of collagen and interactions between collagen, macrophages and fibroblasts play a special role in the self-regulation of reparative CT growth. Collagen restores an impaired self-regulation and exerts a marked therapeutic effect on wounds, burns, trophic ulcers, and other lesions. A similar function may be performed by other matrix components and degradation/secretion products of macrophages and fibroblasts.

Animals↗