[The resistance of low brainstem tissue to free radical oxidation in rats during periodic breathing following hydroxybutyrate treatment].

We evaluated tissue resistance to free radical oxidation, in pentobarbital-anesthetized mongrel albino male rats during pathologic periodic breathing following hydroxybutyrate (GHBA) administration. It was shown that GHBA modulated pro- and antioxidant status of brain tissue. In the absence of periodic breathing after GHBA, decreases in resistance of brainstem tissue membranes to induction of free radical oxidation were slightly pronounced. Rats with GHBA-induced periodic breathing exhibited increased membrane sensitivity of medullar neurons to induction of free radical oxidation. We suggest that cellular metabolism and/or membrane mechanisms of respiratory rhythm-generating neurons play a role in the pathogenesis of periodic breathing.

[Respiratory reactions on microinjections of GABA and baclofen into the Bötzinger complex and the pre-Bötzinger complex in rats].

In adult anaesthetized rats the respiratory reactions to microinjections of GABA (10(-5) M) and baclofen (10(-6) M) into Botzinger complex (BC) and pre-Botzinger complex (PBC) were investigated. It was shown, that GABA microinjections into BC shortened inspiratory time and extended expiratory time while respiratory rate was not changed essentially, under this conditions the tidal volume and ventilation were increased. GABA microinjections into PBC significantly inhibited respiratory rhythm due to inspiratory and expiratory time prolongations and reduced tidal volume. The microinjections of baclofen into BC reduced expiration time and ventilation, and increased respiratory frequency whereas microinjections into PBC increased tidal volume without respiratory rate and expiratory time changes. It is suggested that the reactions observed demonstrate the various contribution of GABAergic mechanisms, including GABA(B)-receptors within BC and PBC, in control of respiratory pattern parameters.

[Electrical stimulation of breathing].

We have generalized data on different breathing electrostimulation methods and have shown their merits and demerits. We have presented electrostimulation methods, the electrostimulators description, different variants of electrodes site, parameters influence. It has shown advantages breathing electrostimulation application in a medical practice.

Effects of electrical stimulation of respiratory center in the event of termination of its natural rhythmic activity.

The possibility of restoration of the natural rhythmic activity of the respiratory system by transcutaneous electrical stimulation of the respiratory center after termination of spontaneous respiratory movements caused by narcosis was shown in experiments on mongrel cats of both sexes under nembutal anesthesia. Natural rhythmic activity of respiratory center was stopped by additional administration of sodium thiopental. The proposed method of electrical stimulation of the respiratory center allows maintaining the rhythmic respiratory movements and their recovery after narcotic apnea up to complete recovery of spontaneous respiration.

[Experience with vascular biografts "KemAngioprotez" in reconstructive surgery of lower-limb major arteries].

Presented herein is the experience with the Russian-made vascular biografts "KemAngioprotez" in 149 patients suffering from atherosclerotic occlusions of the major arteries of the lower extremities and in one female patient with an injury to the superficial femoral artery. A total of 150 reconstructive operations were performed on all segments of the major arterial bed of the lower limbs. The early postoperative period was accompanied by 14 thromboses of the vascular biograft after femoropopliteal reconstruction. It was determined that the likelihood of thrombosis of the vascular biograft depended upon the type of the distal anastomosis, increasing in establishing an "end-to-side" distal anastomosis with the popliteal artery as compared with the "end-to-end" anastomosis technique. No cases of either aneurysmatic deformity, rupture of the vascular graft nor its infection in the early postoperative period were observed. The vascular biograft proved convenient and may therefore be successfully used to replace synthetic vascular grafts and autovenous transplants in reconstruction of the external iliac, femoral and popliteal arteries.

[Effect of phenibut on the respiratory arrest caused by serotonin].

The role of the GABAergic system in mechanisms of the respiratory arrest caused by serotonin administration was studied in anaesthetized rats. Under normal conditions, the systemic administration of serotonin (20-60 mg/kg, i.v.) resulted in drastic changes of the respiratory pattern, whereby the initial phase of increased respiratory rate was followed by the respiratory arrest. The preliminary injection of phenibut (400 mg/kg, i.p.) abolished or sharply reduced the duration of the respiratory arrest phase induced by serotonin. Bilateral vagotomy following the phenibut injection potentiated the anti-apnoesic effect of phenibut, which was evidence of the additive action of vagotomy and phenibut administration. The mechanism of apnea caused by serotonin administration is suggested to include a central GABAergic element, which is activated by phenibut so as to counteract the respiratory arrest.

Effect of opioids on mechanoreflexive respiration control.

The effects of opioids (morphine and fentanyl) on the function of mechanoreceptive respiration regulatory loop were demonstrated. In most opioid-treated rats (74% cases) vagotomy was followed by apneustic respiration with inspiration pause. Excess of opioids in rat CNS produced minor disturbances in the respiration rhythm, but in the absence afferent input from the mechanoreceptors of respiratory pathways and lungs, pronounced periodic apneustic respiration with inspiration pauses developed. The opioidergic system is involved in the formation of respiratory rhythm, but had no appreciable effect on transmission of mechanoreceptive nerve pulses from respiratory pathways and the lungs to the respiratory center.

[Computed tomography in the diagnosis of pulmonary thromboembolism]. / O vozmozhnosti primeneniia komp'iuternoi tomografii v diagnostike tromboémbolii legochnoi arterii.

To verify the hypothetical diagnosis of pulmonary thromboembolism (RTE), 64 patients were provided CT of the chest organs with pulmonary artery opacification, Twenty-seven patients had thromboemboli in different parts of the vascular tree. In 9 patients, the thromboemboli were parietal, with flow preservation at the site of thromboembolus fixation, and in 18 patients, the emboli occluded the vascular lumen. In 11 patients with occlusion of the segmental and subsegmental arteries, the clinical course of RTE, in addition to acute cardiovascular insufficiency, was marked by cough, hemoptysis and pneumoinfarction; the tomograms showed well-defined parts of pneumoinfarction and pleural exudate. In the event of non-occlusion thromboembolism, the clinical picture was only marked by acute cardiovascular insufficiency. In 37 patients, no thromboemboli were discovered in the system of the pulmonary artery. Of these, 27 patients presented, however, with some other pathology of the chest organs.

[Comparative analysis of changes in respiration and systemic hemodynamics during activation of GABA receptors in cats and rats]. / Sravnitel'nyi analiz izmenenii dykhaniia i sistemnogo krovoobrashcheniia u koshek i krys pri aktivirovanii GAMK-retseptorov.

Effects of alpha-hydroxybutyrate (GHB) involved a decrease in the respiration rate and subsequent periodic breathing in anesthetised cats and rats. No considerable changes occurred in systemic circulation. There were, however, some differences between the species in the patterns of respiratory arrest. Possible mechanisms of the similarity and difference are discussed.