Biomaterial Database

[Measuring electrical impedance of organs--instrumental equipment for research and clinical use]. 1991

E Gersing

Zentrum Physiologie und Pathophysiologie, Abteilung Vegetative Physiologie, Göttingen.

An apparatus for measuring the impedance of intact biological organs or parts of organs in the frequency range of 10 Hz to 10 MHz is described. In this range impedance exhibits a large dispersion, which is dependent on tissue structures. The time course of alterations of electrical impedance such as occur during ischemia can be recorded with this equipment. Five specimens in five measuring chambers can be examined simultaneously at different temperatures. In the second part of the article, a portable impedance meter for measuring the modulus of impedance near 200 Hz, the phase of impedance at 5 kHz and the local temperature at the measuring point, is described. These parameters permit an intra-operative evaluation of the changing state of ischemic organs. Sterilizable probes with four surface electrodes and an integrated temperature sensor permit atraumatic measurements at the organ surface. The measurement itself is harmless to the tissue.

UI	MeSH Term	Description	Entries
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D008838	Microcomputers	Small computers using LSI (large-scale integration) microprocessor chips as the CPU (central processing unit) and semiconductor memories for compact, inexpensive storage of program instructions and data. They are smaller and less expensive than minicomputers and are usually built into a dedicated system where they are optimized for a particular application. "Microprocessor" may refer to just the CPU or the entire microcomputer.	Computers, Personal,Microprocessors,Computer, Personal,Microcomputer,Microprocessor,Personal Computer,Personal Computers
D004568	Electrodiagnosis	Diagnosis of disease states by recording the spontaneous electrical activity of tissues or organs or by the response to stimulation of electrically excitable tissue.	Electrodiagnoses
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012815	Signal Processing, Computer-Assisted	Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.	Digital Signal Processing,Signal Interpretation, Computer-Assisted,Signal Processing, Digital,Computer-Assisted Signal Interpretation,Computer-Assisted Signal Interpretations,Computer-Assisted Signal Processing,Interpretation, Computer-Assisted Signal,Interpretations, Computer-Assisted Signal,Signal Interpretation, Computer Assisted,Signal Interpretations, Computer-Assisted,Signal Processing, Computer Assisted
D014022	Tissue Survival	The span of viability of a tissue or an organ.	Organ Survival,Organ Viability,Tissue Viability,Survival, Organ,Survival, Tissue,Viability, Organ,Viability, Tissue
D015687	Cell Hypoxia	A condition of decreased oxygen content at the cellular level.	Anoxia, Cellular,Cell Anoxia,Hypoxia, Cellular,Anoxia, Cell,Anoxias, Cell,Anoxias, Cellular,Cell Anoxias,Cell Hypoxias,Cellular Anoxia,Cellular Anoxias,Cellular Hypoxia,Cellular Hypoxias,Hypoxia, Cell,Hypoxias, Cell,Hypoxias, Cellular
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus