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Biomedical subjects

J Delatizky

Publications and source records attributed to J Delatizky.

4 recordsLinked to original sources
PubMed1986

Myoelectric analysis of the paraspinal musculature in relation to automobile driving.

In this study, the myoelectric activity of 12 paraspinal muscles of ten men aged 18-24 was recorded to examine the effects of backrest inclination and lumbar support in relation to driving. In total, 24 test conditions were evaluated over a 3.5-hour period in a single day. These tests were then repeated, changing the sequence over the next 4 days. The results indicate a complex interaction between the thoracic and lumbar regions of the back with the lowest myoelectric activity position of 120 degrees backrest inclination, 5 cm of lumbar support, and 13.5-18.5 degrees of seat inclination. Electromyogramatic (EMG) evidence of fatigue was not identified over a 3.5-hour period. The generally low levels of EMG activity and, presumably, disc pressure present in any seating position suggest that the paraspinal muscle activity may not play the predominant role in disc herniation as it relates to automobile driving.

Adolescent↗
PubMed1980

Noradrenalin, serotonin, and the dorsal horn.

There is anatomical, pharmacological, and physiological evidence that descending systems from the brain stem using noradrenalin and serotonin (5-hydroxytryptamine, 5-HT) participate in the control of segmental sensory processing. Study of these systems is described in this paper. L-dopa was given intravenously to cats to cause the release of noradrenalin and 5-HT. The resultant effects on the responses of dorsal horn cells to innocuous and noxious thermal stimulation of skin were determined. Using the catecholamine cell neurotoxin, 6-hydroxydopamine, the dopamine beta-hydroxylase inhibitor, fusaric acid, and the tryptophan hydroxylase inhibitor, parachlorophenylalanine, the available central stores of noradrenalin or 5-HT were altered, thus allowing separation of the effects of noradrenalin and 5-HT release on dorsal horn cells. The results indicate that noradrenalin facilitates the responses of dorsal horn cells to innocuous cutaneous stimuli, and has an inhibitory effect on the responses to noxious stimuli. Serotonin inhibits the responses of dorsal horn cells that respond to noxious stimuli, to both innocuous and noxious stimuli. The results are discussed in light of current developments concerning aminergic control of segmental sensory processing.

Animals↗
PubMed1979

The effects of L-dopa on dorsal horn cell responses to innocuous skin stimulation.

The effects of L-DOPA on responses of dorsal horn cells to innocuous mechanical skin stimulation were studied. Following intravenous administration of L-DOPA (10--40 mg/kg) to cats with intact spinal cords, dorsal horn cells, which could be activated by only innocuous or innocuous and noxious stimuli, demonstrated increased reponses manifested by an increase in the average number of spikes per stimulus, increased receptive field size and occasional changes in adequate stimuli. When cats with acute cord transections were studied, L-DOPA increased the responses of cells located in lamina 4 and those cells which responded only to innocuous stimuli; cells which responded to noxious stimuli and those located in other laminae had depressed responses following L-DOPA administration. The inhibitory effects of L-DOPA were in part abolished, in spinal cats, by pretreatment with parachlorophenylalanine, a serotonin depletor. Studies of dorsal cells in chronic spinal cats indicated that the effects of L-DOPA were largely dependent on functioning terminals of descending suprasegmental pathways. The conclusion was reached that descending noradrenergic pathways, indirectly, cause an increase in transmission from cutaneous afferents to dorsal horn cells and that some of the inhibitory effects of L-DOPA described by others are a manifestation of L-DOPA interactions with inhibitory serotonergic systems.

Animals↗