Comparison of biomechanical properties of light mesh endoprostheses with different structural characteristics.

Three types of light mesh endoprostheses with different jersey structure were implanted into the anterior abdominal walls of 18 rabbits. Changes in the geometrical size and mechanical properties of the prostheses detected 3 months after implantation largely depended on the jersey structure and distribution of mature connective tissue in the structure of the material.

[The dynamics of the evacuation of carbohydrate and fatty food from the stomach and duodenum]. / Dinamika évakuatsii iz zheludka i dvenadtsatiperstnoi kishki uglevodnoi i zhirovoi pishchi.

The dynamics of the duodenal chyme evacuation depended on the absolute quantity of the stomach-evacuated food in dogs. The evacuation of the carbohydrate food was exponential. Fat food was evacuated in equal portions from the stomach and duodenum. The carbohydrate and fat food evacuation from the stomach and duodenum seems to be highly coordinated.

[An electromyographic method for determining the antihypoxic activity of preparations]. / Elektromiograficheskii metod opredeleniia protivogipoksicheskoi aktivnosti preparatov.

To measure drug antihypoxic activity, an electromyographic method was worked out. The main idea of the method is to estimate the influence of these substances on the amplitude of slow electric waves of smooth muscles on an isolated strip of rat small intestine in situ. This parameter whose value directly depends on tissue pO2 was recorded under the conditions of artificial ischemia of the intestinal strip. Circulatory hypoxia was simulated by the clamping of mesentery vessels, and the time was determined, during which the amplitude of slow electric waves reduced to 1/3 of the initial value in control animals and rats treated beforehand with the drugs under study. Antihypoxic activity of the drugs was calculated as difference in these time intervals between experiment and control, given in per cent.

[The vagus regulation of the electrical activity of the contractile apparatus in the small intestine of rats under normal and pathological conditions]. / Vagusnaia reguliatsiia élektricheskoi aktivnosti sokratitel'nogo apparata tonkoi kishki krys v normal'nykh i patologicheskikh usloviiakh.

The role of parasympathetic division of the vegetal nervous system in regulation of the small intestine motor activity under the normal and pathological conditions was estimated using multifactorial quantitative analysis of the electrical activity of its smooth muscle under the conditions of vagotomy, chronic duodenal ulcer and their combination. Switching off the intestine vagal innervation led to its weakened and altered motor activity, most pronounced on the 3rd and 30th day. Development of the duodenal ulcer is accompanied by the increased motor activity of the intestine with the spasm phenomena, later complemented by disturbed activity of the pacemaker and disturbed myogenic distribution of the electric complex (the most pronounced changes have been noted on the 10th, 40th and 230th day). Vagotomy under the condition of duodenal ulcer normalizes (relaxes) the small intestine motor activity.

[Changes in the contractile and bioelectrical activities of the rat small intestine under increased intra-abdominal pressure]. / Izmenenie kontraktil'noi i bioélektricheskoi aktivnosti tonkoi kishki krys pri povyshenii vnutribriushnogo davleniia.

A relationship was established between the increased intra-abdominal pressure and decreased electrical and mechanical motor activity of the small intestine in rats. Possible pathophysiological mechanisms are discussed. A model was developed for estimation of the electrical and motor activity of the small intestine in rats, which can be used for experimental studies of conditions where intra-abdominal pressures can be elevated.

[Changes in reactivity of the contractile system of the small intestine caused by disturbed parasympathetic innervation]. / Izmenenie reaktivnosti sokratitel'nogo apparata tonkoi kishki v usloviiakh narushennoi parasimpaticheskoi innervatsii.

We studied the role of parasympathetic division of vegetative nervous system in regulation of the intestine activity in rats subjected to bilateral subdiaphragmal vagotomy, the response of the neuromuscular apparatus of the small intestine to stimulation by aceclydine taken as an example. Intravenous injection of aceclydine (0.5 mg/kg) into intact animals is accompanied by characteristics changes in the electrical and contractile activities of the intestine, which reflect its enhanced motor activity. Vagotomy leads to changes of response of the intestine to pharmacological stimulation, most expressed within 3, 7, and 30 days. It was proposed that distortion of reactive properties of the intestine contractile system under these conditions is related to functional changes in rhythm-setting neurons of intramural ganglia and M-cholinoreceptors of neuromuscular synapses.

[The role of the parasympathetic nervous system in regulating the kinetics of the regional blood circulation in the digestive system organs]. / Rol' parasimpaticheskoi nervnoi sistemy v reguliatsii kinetiki regionarnogo krovoobrashcheniia v organakh pishchevaritel'noi sistemy.

Cranio-bulbar part of the parasympathetic nervous system proved to be important for regulation of the blood flow distribution between the organs of the gastroduodenal complex (liver, stomach, and small intestine), rate of the local blood flow and its kinetics. Investigation of the blood supply of the above mentioned organs various periods (1-60 days) after bilateral subdiaphragmatic truncal vagotomy has demonstrated the most pronounced transformations in macro- and micro-hemodynamics in the 14-30 days period. Time pattern of these changes has one maximum in liver and stomach (14-30 days) and two maxima (7 and 30 days) in small intestine.

[The role of the duodenojejunal junction in regulating the evacuatory function of the duodenum]. / Rol' duodeno-eiunal'nogo perekhoda v reguliatsii évakuatornoi funktsii dvenadtsatiperstnoi kishki.

Chronic experiment on dogs was performed to study the effect of duodenojejunal junction exclusion from the evacuatory process on dynamics of gastric and duodenal emptying of the carbohydrate and fatty food. It is established that in the case of exclusion of the duodenojejunal junction, the degree of coordination of gastric and duodenal emptying decreases, dynamics of chyme evacuation from the duodenum considerably changes. It is concluded that the duodenum is not a mere transporter of food coming from the stomach, but has its own regulation mechanisms represented by the duodenojejunal junction and the Treitz ligament.

[The diagnosis of motor disorders of the small intestine in peritonitis in children and the rationale for pathogenetic methods of correction]. / Diagnostika dvigatel'nykh narushenii tonkoi kishki pri peritonite u detei i obosnovanie patogeneticheskikh metodov korrektsii.

The work deals with the results of experimental (200 animals) and clinical (20 patients) study into the role of the efferent link of the autonomic nervous system in regulating motor activity of the small intestine and the possibility of using direct electroenteromyography in the diagnosis of the stages of paresis and the degree of motor disorders in peritonitis. The pathogenetic methods of treatment of intestinal paresis are substantiated. Medicamentous stimulation of the cholinergic nervous system in peritonitis is effective only when intactness of the intramural ganglia is maintained, in which case the electroenteromyographic test with neostigmine methylsulfate or cerucal may be conducted. The pathogenetic method of treatment in all other cases is medicamentous blockade of the adrenergic nervous system.

[Can perforated ulcer be not sutured?]. / Mozhno li ne ushivat' perforativnuiu iazvu?

Experiments in 5 pigs and 18 mongrel dogs have shown the possibility to close perforating ulcers with plates of biopolymer "Tachocomb". The method is proposed as an alternative to suturing perforations in the zone of pylorus in order to prevent stenosis of the pyloric part of the stomach. The experimental data obtained have confirmed good adhesive and stimulating properties of the fibrin-collagen substance. Successful results of using the method were demonstrated in 2 patients with perforating ulcers.

[Structural and functional organization of the upper esophageal sphincter]. / Strukturno-funktsional'naia organizatsiia verkhnego pishchevodnogo sfinktera.

Using traditional anatomical and histological methods, the muscle envelope of the pharynx-esophagus junction was investigated in humans and dogs. In the upper (cranial) portion of the esophagus of man and dogs, an inferior anatomical sphincter was detected which histologically can be referred to the group of rhabdo-sphincters. The upper esophageal sphincter is a purely esophageal structure which in man is located at a distance of 25-30 cm from the maxillary incisors. In adult humans, it is 25-30 mm long and is situated obliquely to the long esophageal axis. The posterior semicircle of the sphincter is located higher than the anterior one. In the area of the upper esophageal sphincter the esophageal wall is of different thickness. Due to the muscle envelope and submucous membrane of the base, the right wall is 1.7-2.0 times thicker than the left, anterior or posterior wall. The data obtained from fiber esophagoscopy of patients and electromyography of the pharynx-esophagus junction of dogs have shown that the upper (cranial) esophageal sphincter control food passage from the pharynx to the esophagus and prevents food reflux to the laryngopharynx, protecting airways from aspiration.

[The role of the nervous factor in regulation of oxygen supply to the small intestine]. / Znachenie nervnogo faktora v reguliatsii kislorodnogo snabzheniia tonkoi kishki.

The experimental model of rat bilateral subdiaphragmatic stem vagotomy was used to study the role of parasympathetic nervous system in regulation of circulation and oxygen supply to the small intestine. Cut of the vagus nerves is shown to cause redistribution of the blood flow between gastroduodenal organs, to slow down local circulation, to reduce oxygen tension in the muscular lining of the jejunum, to raise water content in the wall and change magnetorelaxational characteristics. Morphologically this manifested in altered arteriolar and capillary configuration, dilation of the capacity microvessels, dystrophia of microvessel wall, red cell aggregation in capillaries and venules, defective permeability of the vascular wall. The above indices changed most 7 and 30 days after vagotomy. It is evident that impaired vagus innervation produces secondary circulation hypoxia in the small intestine.

Protective effect of complex antioxidant preparation containing vitamins and amino acids in rats with burn trauma complicated by endotoxemia.

Burn trauma increased blood chemiluminescence, while lipopolysaccharide in a dose of 1 mg/kg potentiated this effect, activated LPO, and decreased plasma antioxidant activity. In erythrocytes, superoxide dismutase activity increased, while activity of peroxide-utilizing enzymes decreased. Myeloperoxidase content increased in the lungs and epidermis. The preparation of alpha-tocopherol, selenium aspartate, and ubiquinone abolished the effect of lipopolysaccharide, but did not modulate the increase in chemiluminescence under the influence of this agent.