Biomaterial Database

[Postmortem behavior of impulse transmission latency--impulse transmission strength curves]. 1991

B Madea

Institut für Rechtsmedizin, Universität zu Köln.

Strength-duration curves (i/t-curve) are describing the dependence of the threshold intensity of rectangular impulses from their duration; in clinical neurophysiology they help to clarify whether a muscle is denervated or not. In the post-mortem interval from 2 to 9 hpm the pm. changes of strength-duration-curves were investigated on 17 bodies; muscular contraction was objectified using a sensitive force transducer pricked into the muscle. The muscle was stimulated with constant-current rectangular impulses of 5 to 1000 msec. duration and current intensities which produce a force of muscular contraction of 2.5 mN each half an hour. The strength-duration-curves of human bodies taken at the earliest possible time p. m. (2 hpm) show already the pattern of partially or total denervation (steep rise of threshold values for duration of stimuli shorter than 100 msec). As for the rheobase there is a strong linear relationship between ln of the threshold and time since death for duration of stimuli below 1000 msec. Extrapolation of the time since death on the basis of threshold values of different duration of stimulations of an i/t-curve reveals only small rise of precision of death time estimation compared to extrapolation of the time since death just with the rheobase.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008875	Middle Aged	An adult aged 45 - 64 years.	Middle Age
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D010525	Peripheral Nerves	The nerves outside of the brain and spinal cord, including the autonomic, cranial, and spinal nerves. Peripheral nerves contain non-neuronal cells and connective tissue as well as axons. The connective tissue layers include, from the outside to the inside, the epineurium, the perineurium, and the endoneurium.	Endoneurium,Epineurium,Perineurium,Endoneuriums,Epineuriums,Nerve, Peripheral,Nerves, Peripheral,Perineuriums,Peripheral Nerve
D011180	Postmortem Changes	Physiological changes that occur in bodies after death.	Adipocere,Algor Mortis,Cruor,Livor Mortis,Change, Postmortem,Changes, Postmortem,Postmortem Change
D011930	Reaction Time	The time from the onset of a stimulus until a response is observed.	Response Latency,Response Speed,Response Time,Latency, Response,Reaction Times,Response Latencies,Response Times,Speed, Response,Speeds, Response
D012016	Reference Values	The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.	Normal Range,Normal Values,Reference Ranges,Normal Ranges,Normal Value,Range, Normal,Range, Reference,Ranges, Normal,Ranges, Reference,Reference Range,Reference Value,Value, Normal,Value, Reference,Values, Normal,Values, Reference
D005260	Female		Females