ABSTRACT
The effect of 30-min vector potential variation on the phagocytosis of macrophages from laboratory mice was investigated. It was found that the effect changes the characteristics of mice immunity: the quantity and percentage of neutrophils and lymphocytes in the blood, the activity of capture, degranulation, the splitting of bacterial agents, and the dynamics of formation of reactive oxygen species.
Subject(s)
Electromagnetic Fields , Monocytes/radiation effects , Animals , Cell Adhesion , Cell Degranulation/radiation effects , Enzyme Activation , Leukocyte Count , Leukocytes/cytology , Leukocytes/radiation effects , Macrophages, Peritoneal/immunology , Macrophages, Peritoneal/physiology , Macrophages, Peritoneal/radiation effects , Mice , Mice, Inbred CBA , Monocytes/cytology , Monocytes/immunology , Oxygen/metabolism , Peroxidase/metabolism , Phagocytosis , Reactive Oxygen Species/metabolism , Staphylococcus aureus/immunologyABSTRACT
The purpose of the study was to design and investigate the closed-loop propofol system (CLPS) with a mean arterial pressure (MAP) controller in open-heart surgery. CLPS consists of a 386 PC, a blood pressure sensor and an infusion pump. The C language computer program sets the propofol infusion rate based on an empirical algorithm including proportional component to maintain the measured MAP more closely to the target MAP (85% of patient standard MAP). The propofol concentrations were calculated by the pharmacokinetic/pharmacodynamic model differential equations solving every 30s. CLPS was used in 214 NYHA II-IV patients, aged 16-74, undergoing various open-heart procedures. The mean target MAP was 75.2 +/- 4.5 mm Hg. The measured and target MAP difference did not exceed 22% perioperatively. The bispectral index varied from 42.7 +/- 1.2 (tracheal intubation) to 41.8 +/- 0.1 (skin suture) with a variation of the propofol site effect concentration ranging from 2.9 +/- 0.09 to 1.8 +/- 0.1 microg/ml. It was a closed negative correlation (r = 0.84; p < 0.01) between the propofol site effect and the MAP during the initial period of anesthesia. There were not any significant changes in the blood cortisole level during the procedures. The recovery time was 1.4 +/- 1.5 min after propofol infusion; 95.5% of patients were extubated in the operating room.
Subject(s)
Anesthesia, General/methods , Feedback/physiology , Hypnotics and Sedatives/administration & dosage , Monitoring, Intraoperative/methods , Propofol/administration & dosage , Signal Processing, Computer-Assisted , Adolescent , Adult , Aged , Algorithms , Anesthesia, General/instrumentation , Blood Pressure/physiology , Cardiovascular Surgical Procedures , Female , Humans , Male , Middle Aged , Monitoring, Intraoperative/instrumentationABSTRACT
The computerized mock circulation system is described for analyzing the hydrodynamic characteristics of artificial heart valves. Flow studies have been carried out on 6 mechanical valves of various types. The volumetric flow, pressure upstream and downstream were measured and the mean systolic pressure drop and energy losses were calculated. The commercial model of the EMIKS valve shows much lower values of pressure drop and one of the smallest value of energy losses among the tested artificial heart valves.
Subject(s)
Heart Valve Prosthesis/standards , Software , Humans , Models, Cardiovascular , PressureABSTRACT
Methods to check the back-feed resistivity of the artificial heart valve in static mode have been worked out. These methods allow one to check the resistivity of the closed valve to the revert liquid flow or liquid leakage through it when the new prostheses are tested. The comparative tests of two biovalves and eight mechanical prostheses were carried out. It was stated that among the mechanical valves, which are most widely used in the hospitals (disk, ball and triaflet) the highest resistance when closed has the silicon ball aortic valve AKCh-4-0.6 (Sh).
Subject(s)
Aortic Valve/physiopathology , Bioprosthesis/standards , Heart Valve Prosthesis/standards , Feedback , Hemodynamics , Humans , MethodsABSTRACT
The flow of blood as a viscous, Newtonian, incompressible liquid in an expanding spherical cavity with a ball-type inlet valve was examined. This type of flow can serve as a model of the phase of ventricular diastole in a sac-type artificial heart. The critical values of Reynolds numbers at which flow interruption behind the valve occurs were found. The optimum geometric ratios of the dimensions of the ventricular cavity and valve that permit a decrease in the input resistance of the cavity, the size of the valve, and the surface tensions in the bloodstream were determined.
Subject(s)
Blood Flow Velocity , Blood Viscosity , Heart, Artificial , Models, Cardiovascular , Biomechanical Phenomena , Mathematics , Ventricular FunctionABSTRACT
During the recent years various investigators have developed the technique of kryophotometric measurements of oxyhemoglobin saturation with oxygen (psi) in small vessels. In this paper, on the basis of the statistical model of the organ developed by the authors, a theoretical relationship is established between the distributions of measured in various groups of experiments in the capillaries and the distributions of psi in the arterioles and venules. It is shown that for the description of the distribution of psi in a separate multicapillary unit, lying between the arteriole and the venule, it is possible to introduce a special distribution function. In some cases this function may be determined analytically. Statistical distributions of other microcirculation parameters may be included into the statistical model of the organ using the similar procedure described in this paper for the parameters psi a' psi v- arteriolar and venular psi.
