Changes in electrical resistivity of swine liver after occlusion and postmortem

• Published in: Medical & biological engineering & computing Vol. 40; no. 1; pp. 29 - 33
• Main Authors: HAEMMERICH, D, OZKAN, O. R, TSAI, J.-Z, STAELIN, S. T, TUNGJITKUSOLMUN, S, MAHVI, D. M, WEBSTER, J. G
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 2002; Springer Nature B.V
• Subjects: Animals; Biological and medical sciences; Biomedical engineering; Electric Impedance; Fundamental and applied biological sciences. Psychology; Gastroenterology. Liver. Pancreas. Abdomen; Ischemia - physiopathology; Liver; Liver - blood supply; Liver - physiopathology; Liver. Bile. Biliary tracts; Liver. Biliary tract. Portal circulation. Exocrine pancreas; Medical sciences; Membrane Potentials; Other diseases. Semiology; Studies; Swine - physiology; Vertebrates: digestive system; Animal model; Digestive system; Liver; Postmortem; Cardiovascular disease; Hepatic disease; Experimental study; Time variation; Automatic processing; Vascular disease; Electrodes; In vivo; Vertebrata; Mammalia; Ischemia; Swine; Animal; Electric resistivity; Digestive diseases; Artiodactyla; Membrane channel; Resistor; Ungulata; Comparative study
• ISSN: 0140-0118; 1741-0444
• DOI: 10.1007/bf02347692

The resistivity of swine liver tissue was measured in vivo, during induced ischaemia and post-mortem, so that associated changes in resistivity could be quantified. Plunge electrodes, the four-terminal method and a computer-automated measurement system were used to acquire resistivities between 10Hz and 1 MHz. Liver resistivity was measured in vivo in three animals at 11 locations. At 10 Hz, resistivity was 758 +/- 170 ohm x cm. At 1 MHz, the resistivity was 250 +/- 40 ohm x cm. The resistivity time course was measured during the first 10 min after the liver blood supply in one animal had been occluded. Resistivity increased steadily during occlusion. The change in resistivity of an excised tissue sample was measured during the first 12h after excision in one animal. Resistivity increased during the first 2h by 53% at 10 Hz and by 32% at 1 MHz. After 2h, resistivity decreased, probably owing to membrane breakdown. The resistivity data were fitted to a Cole-Cole circle, from which extracellular resistance Re, intracellular resistance Ri and cell membrane capacitance Cm were estimated. Re increased during the first 2h by 95% and then decreased, suggesting an increase in extracellular volume. Cm increased during the first 4 h by 40%, possibly owing to closure of membrane channels, and then decreased, suggesting membrane breakdown. Ri stayed constant during the initial 6h and then increased.