ABSTRACT
Application of a modern method of introscopy--electroimpedance tomography (EIT) for diagnosis of different types of lung diseases is described. The EIT system including measurement and collecting data devices, 16-electrodes array and IBM PC 486 computer was used. The results of analysis of electrotomograms have demonstrated that the EIT-system can be introduced for detecting abnormal lung fluid levels, pulmonary edema, diagnosis of lung cancer, emphysema, pleuritis, hydrothorax, sarcoidosis. The method provides high sensitivity to the changes in the body physiological state. Other advantages are: safety, fast measurements, ease of equipment transportation and maintenance, low cost.
Subject(s)
Electric Impedance , Pulmonary Medicine/methods , Tomography/methods , Adult , Aged , Electrodes , Female , Humans , Lung Diseases, Obstructive/diagnosis , Lung Neoplasms/diagnosis , Male , Microcomputers , Middle Aged , Pulmonary Medicine/instrumentation , Sarcoidosis, Pulmonary/diagnosis , Tomography/instrumentationABSTRACT
The paper deals with the use of the present-day highly effective method of introscopy electric impedance tomography (EIT) for diagnosis latent abnormalities during mass screening. EIT images viscera and tissues on the basis of their electric conductivity differences. Reconstruction of the images reflecting the distribution of electric conductivity values in the body is made from the recording potentials onto the body's surface while passing currents through the electrodes located along the circumference of the body's part under study. The 16-electrode EIT system developed by Dipol (Moscow) was used to examine the distribution of electric conductivity values in the extremities and chest organs in healthy volunteers of both sexes and in patients with various pulmonary diseases.
Subject(s)
Electric Impedance , Mass Screening , Tomography/methods , Animals , Cattle , Diagnosis, Differential , Dogs , Electrodes , Female , Humans , Lung Diseases/diagnosis , Male , Middle Aged , Rabbits , SwineABSTRACT
Inner diameter, absolute and relative wall thickness, and blood flow velocity in arterioles of different branching orders were measured in the rat skeletal (cremaster) muscle. It was found that as the branching order increased the heterogeneity of arterioles with respect to their relative wall thickness also grew. In response to papaverine-induced relaxation of the smooth muscle, there was a direct correlation between vasodilatation and the relative wall thickness. It was shown that a degree of smooth muscle shortening in different arterioles varied widely, the relative wall thickness being a measure (characteristic) of this shortening.
Subject(s)
Arterioles/physiology , Muscles/blood supply , Vascular Resistance/physiology , Animals , Arterioles/anatomy & histology , Arterioles/drug effects , Male , Microscopy/instrumentation , Microscopy/methods , Papaverine/pharmacology , Rats , Vascular Resistance/drug effects , Vasodilation/drug effects , Vasodilation/physiologyABSTRACT
Action of the synthetic substance P (SP1-11) and its modified fragment (MSP1-4) on microhemodynamics was investigated in experiments. Significant hypotensive effect and reduction of blood flow velocity in rat mesenteric microvessels were produced by both substances, no changes of microvessels diameter were observed. Effective concentrations of the SP1-11 and MSP1-4 were revealed, being 10(-6) M and 10(-4) M, respectively. Organ specificity of substance P vascular effects is suggested.
Subject(s)
Hemodynamics/drug effects , Peptide Fragments/pharmacology , Substance P/pharmacology , Animals , Blood Flow Velocity , Blood Pressure/drug effects , Male , Microcirculation/drug effects , Organ Specificity , Rats , Rats, Inbred StrainsABSTRACT
Blood flow velocities in microvessels of the rat intestinal mesentery were determined by means of prism-grating method. Mean velocity values in arterioles were 1.9 +/- 0.1, in venules 1.2 +/- 0.2, in capillaries 0.82 +/- 0.06 and in arteriole-venule anastomoses 1.7 +/- 0.2 mm/s. These values do not vary significantly in arterioles with internal diameter from 23.2 to 6.9 mm and in venules from 7.2 to 28.2 mm. The most significant velocity changes appear in the passage of arterioles into capillaries (50%) and between capillaries and venules (40%).
Subject(s)
Blood Flow Velocity , Splanchnic Circulation , Animals , Arterioles/anatomy & histology , Arterioles/physiology , Arteriovenous Anastomosis/anatomy & histology , Arteriovenous Anastomosis/physiology , Capillaries/anatomy & histology , Capillaries/physiology , Male , Microscopy/instrumentation , Rats , Transducers, Pressure , Venules/anatomy & histology , Venules/physiologyABSTRACT
Equations reflecting relationships between the thickness of blood vessel wall (w) and internal radius (r) of the vessel during the process of smooth muscle fiber contraction involved two types of the fibers orientation in vessel wall: at an angle of 45 degrees and 90 degrees to the longitudinal axis of the vessel. Experimental values of w and r were determined on arterioles of the rat mesentery after vasopressin or epinephrine administration. According to the degree of longitudinal and transversal efforts participation in the process of vessel closure, heterogeneity of the arterioles was revealed by comparison of the theoretical and experimental values of w and r. The ability of arterioles for closure did not depend on the initial value of relative vessel wall thickness (w/r).
