[Resection of leiomyosarcoma of the inferior vena cava].

Experience in treatment of leiomyosarcoma of the retrohepatic segment of the inferior vena cava at any separately taken clinic is scarce. Given a rare nature of the pathology involved, whose diagnosis and management require joint participation of various-specialty physicians, we have considered it wise to present our own clinical case report.

[Positive experience in long-term follow-up and surgical management of a stenosing lesion of the thoracoabdominal portion of the aorta and its branches in non-specific aortoarteritis].

The article is based on experience gained in 25-year follow-up of a female patient presenting with pathology of the thoracoabdominal aorta and its branches in non-specific aortoarteritis. Discussed herein are clinical peculiarities of the development and course of the disease, analysing the outcomes of the reconstructive operations performed, followed by due assessment of efficacy of long-term treatment.

A proprioceptive role for an exteroceptive mechanoafferent neuron in Aplysia.

Afferent regulation of centrally generated activity is likely to be more complex than has been established. We show that a neuron that is an exteroceptor can also function as a proprioceptor. We study the Aplysia neuron B21. Previous data suggest that B21 functions as an exteroceptor during the radula closing/retraction phase of ingestive feeding. We show that the tissue innervated by B21, the subradula tissue (SRT), is innervated by a motor neuron (B66) and that B66-induced SRT contractions trigger centripetal spikes in B21. Thus, B21 is also a proprioceptor. To determine whether exteroceptive and proprioceptive activities occur during the same phase of ingestive feeding, we further characterize B66. We show that B66 stimulation does not close or retract the radula. Instead it opens it. Moreover, B66 is electrically coupled to other opening/protraction neurons. Finally, we elicit motor programs in semi-intact preparations and show that during radula opening/protraction we observe B66 activity, SRT contractions, and spikes in B21 that can be eliminated if B66 is indirectly hyperpolarized. B21 is, therefore, likely to act as an exteroceptor during one phase of ingestive feeding and as a proprioceptor during the antagonistic phase. Previous experiments have shown that centripetal spikes in B21 are only transmitted to one follower if they are "gated in" by depolarization. During ingestive programs B21 is centrally depolarized during closing/retraction, but it is not depolarized during opening/protraction. We sought to determine whether there are other followers that receive B21 input when it is not centrally depolarized. We found one such cell. Moreover, we found that stimulation of B21 during radula opening/protraction significantly decreases the duration of this phase of behavior. Thus, proprioceptive activity in B21 is likely to have an impact on motor programs.

Effect of a serotonergic extrinsic modulatory neuron (MCC) on radula mechanoafferent function in Aplysia.

The serotonergic metacerebral cells (MCCs) and homologous neurons in related mollusks have been extensively investigated within the context of feeding. Although previous work has indicated that the MCCs exert widespread actions, MCC modulation of sensory neurons has not been identified. We characterized interactions between the MCCs and a cell that is part of a recently described group of buccal radula mechanoafferents. The cell, B21, has a peripheral process in the tissue underlying the chitinous radula [the subradula tissue (SRT)]. Previous studies have shown that B21 can fire phasically during ingestive motor programs and provide excitatory drive to the circuitry active during radula closing/retraction. We now show that activity of B21 can be modulated by serotonin (5-HT) and the MCCs. Centrally, although a slow depolarization is typically recorded in B21 as a result of MCC stimulation, this depolarization does not cause B21 to spike. It can, however, increase B21 excitability enabling a pulse that was previously subthreshold to elicit an action potential in B21. B21 is in fact rhythmically depolarized during the radula closing/retraction phase of ingestive motor programs. Thus central effects of the MCCs on radula mechanoafferent activity are only likely to be apparent while B21 is receiving input from the feeding central pattern generator. Peripherally, radula mechanoafferent neurons can be activated 1) when a mechanical stimulus is applied to the biting surface of the SRT and 2) when the SRT contracts. MCC stimulation and 5-HT modulate B21 responses to both types of stimuli. For example, MCC stimulation and low concentrations of 5-HT cause subthreshold mechanical stimuli applied to the SRT to become suprathreshold. 5-HT and MCC stimulation also enhance SRT contractility. Peripheral effects of MCC activity are also likely to be phase dependent. For example, MCC stimulation does not cause B21 to respond to peripheral stimuli with an afterdischarge. Consequently, radula mechanoafferents are likely to be activated when food is present between the radula halves during radula closing/retraction but are not likely to continue to fire as opening/protraction is initiated. In a similar vein, MCC effects on the contractility of the SRT will only be apparent when contractions are elicited by motor neuron activity. SRT motor neurons are rhythmically activated during ingestive motor programs. Thus we have shown that radula mechanoafferent activity can be modulated by the MCCs and that this modulation is likely to occur in a phase-dependent manner.

[The use of monoclonal antibodies to lipid A for the correction of the hemodynamic disorders in endotoxemia]. / Ispol'zovanie monoklonal'nykh antitel k lipidu A dlia korrektsii gemodinamicheskikh narushenii pri éndotoksemii.

Endotoxemia induced by gram-negative bacteria leads to endotoxic shock pathogenetically stemming from the integral component of the bacterial wall--lipid A. The study made to define the ability of lipid A monoclonal antibodies to correct hemodynamic disturbances due to endotoxemia in dog experiments showed the efficacy of the antibodies administration. ReLPS isolated from Salmonella Minnesota was used as an antigen. Administration of the complex monoclonal antibodies-endotoxin caused no hemodynamic impairment.

[Experimental ultrasound contrast study of the myocardium]. / Ul'trazvukovoe kontrastnoe issledovanie miokarda v éksperimente.

The ultrasound contrast medium obtained by the original methods was administered into the left ventricular cavity and myocardium of 12 open-chest dogs by using a catheter. After its administration into the cavity there was its intensive contrast. When the ultrasound contrast was administered into the aortic root, the entire myocardium contrasted, on selective administrations of the contrast into the coronary arteries, the beds supplied by appropriate arteries contrasted. The ultrasound contrast study enabled the areas with impaired perfusion as echo-negative "filling defects" to be detected and mapped. The imaging of myocardial blood flow in tomographic sections and real time allows one to regard it promising for clinical use.

[A comparative evaluation of myocardial protection based on criteria not associated with the quality of myocardial conservation]. / Sravnitel'naia otsenka metodov miokardial'noi zashchity na osnove kriteriev, ne sviazannykh s kachestvom sokhraneniia miokarda.

Based on the rich clinical material (405 patients), the authors have assessed the most common blood and crystalloid cardioplegic techniques by applying the criteria which do not apply to those of myocardial protection adequacy. Differences have been found between the methods in the volumes of blood loss, the number of patients operated on without utilizing donor blood, terms of aortic occlusion at one-stage operative interventions, recovery of cardiac performance after aortic occlusion. The differences found are essential in choosing the type of cardioplegia by taking into account the individual traits of each surgical intervention and an operating surgeon's opinions.

[Prospective modeling of coronary bypass surgery]. / Perspektivnoe modelirovanie operatsii koronarnogo shuntirovaniia.

Operation for mammary-coronary shunting was reproduced on experimental dogs. Myocardial perfusion during shunting was accomplished through a shunt, passing in the mammary artery and introduced into the distal part of the coronary artery through an incision. This allowed the use of extracorporeal circulation and the development of myocardial ischemia to be avoided. The method makes it possible to create stenoses in any part of the vascular block. The authors analysed the dependence between the coronary blood flow and the pressure in the left ventricle and aorta by means of a mathematical model, which made it possible to separate the effect produced on the coronary blood flow by such parameters as the resistance and capacity of the large vessels, resistance of small vessels, pressure of arrest of the blood flow, and extravascular compression.

[Perspective modeling of coronary bypass surgery]. / Perspektivnoe modelirovanie operatsii koronarnogo shuntirovaniia.

Mammary coronary bypass surgeries were performed in canine experiments. Myocardial perfusion was done via a shunt passing within the mammary artery and inserted into the distal portion of a coronary artery through a section, avoiding the application of extracorporeal circulation and myocardial ischemia. The method creates stenoses in any area of a vessel unit. A relationship was examined between coronary blood flow, left ventricular and aortic pressures by using a mathematical model that covers the effects of such parameters as resistance of great vessels, their capacity, minor vascular resistance, blood flow arrest and extravascular compression pressures on coronary blood flow.

[Effects of low doses of activated protein C in experimental arterial thrombosis in rats]. / Vliianie malykh doz aktivirovannogo proteina C na éksperimental'nyi arterial'nyi thromboz u krys.

Activated C protein (ACP) is a physiological anticoagulant enzyme that is capable to inactivate factors Va and VIIIa, thereby having a wide spectrum of antithrombotic effects. Low-dose ACP was tested for its ability to affect anodic current-induced arterial thrombosis in the rat. ACP given in low doses (15 micrograms/kg, 7% of total C protein in the rat) was found to produce a marked antithrombotic effect. With this, the activated partial thromboplastin time remained virtually unchanged, and its antithrombotic action was equal to that of heparin administered in a dose of 125 U/kg. In the authors' opinion, ACP may form the basis for designing a highly effective antithrombotic agent.

[Effect of graduated embolization of the coronary vessels using microspheres on the pumping function and contractility of the left ventricle in rats]. / Vliianie dozirovannoi émbolizatsii koronarnykh sosudov mikrosferami na nasosnuiu funktsiiu i sokratimost' levogo zheludochka u krys.

Left ventricle (LV) function and systemic hemodynamic changes after coronary artery embolization by 15 microns radioactive microspheres were studied in anesthetized rats. Selective coronary embolization was produced by microsphere injection during ascending aorta occlusion in closed chest animal by using "L"-shaped wire. Maximal pressure (Pmax) developed was evaluated during ascending aorta occlusion. Coronary embolization evoked dose-dependent reduction in Pmax and dP/dtmax and then decrease in basal LV systolic pressure. dP/dt/P, with parallel increase in end diastolic LV pressure. Changes of cardiac output were bidirectional: after administration of relatively small amount of microspheres cardiac output increased. This method can be used for producing quantitative myocardial ischemia and we suggest that it may be a suitable model of the chronic heart failure.

[A model of the coronary vascular bed and its verification by a physiological experiment]. / Model' koronarnogo sosudistogo rusla i ee proverka v fiziologicheskom éksperimente.

We analysed the relationship between artery pressure (AP) and coronary flow (F) in the canine coronary bed, using an electrical analog model of the coronary circulation. The model contained a capacitance of epicardial vessels, input and terminal resistances, diode, and the number of e.m.f., simulated the intramyocardial pressure and zero-flow pressure. These e.m.f. are assumed to be a linear functions of left ventricular and aortic pressure. The value of coronary blood flow was calculated from experimental curves of AP and LVP and setting parameters. Good agreement was obtained between theoretical and experimental curves of coronary blood flow.