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Biomedical subjects

O Robin

Publications and source records attributed to O Robin.

13 recordsLinked to original sources
PubMed1995

The ohmic perturbation duration, an original temporal index to quantify electrodermal responses.

The reactivity of the autonomic nervous system was (D.C.) recorded using six parameters simultaneously. Such a device permitted to describe a new index of skin resistance response (SRR). The ohmic perturbation duration (O.P.D. index) was defined as the period during which the subject is effectively responding to the stimulation. O.P.D. index was easily quantified because the specific part of the response, showing many fluctuations at a low resistance level, can be distinguished from the recovery part without fluctuations or with smaller microevents of different kinds. Moreover, the slope of this fluctuation is identical to that observed just before the stimulation. The comparison between the values of the O.P.D. index and classically used SRR durations enabled us to calculate the identity percentages from five other neurovegetative parameters. Results showed high values for the skin potential (91%) and skin blood flow (82.5%). These values were smaller as far as skin superficial temperature (50.5%), heart (40.8%) and respiratory (46.5%) variations were concerned. Nonetheless these last three percentages were still higher than those usually obtained with the values of the correlation coefficients from different, simultaneously recorded parameters. O.P.D. index comparison with four other classical used temporal indices (recovery time, 1/3, 1/2 and 2/3 of the recovery time) show a high significant concordance in O.P.D. index opposed to aleatory one obtained with these four other durations. Thus, the O.P.D. index could be an appropriate measure of electrodermal response (EDA) allowing any stimulus to be temporarily quantified towards sympathetic activation induced response.

Adult↗
PubMed1985

A comparison of energy metabolism and the effects of beta-adrenergic stimulation in the tongue and attached gingiva of the dog.

Glucose-6-phosphate (G6P), ATP, phosphorylcreatine (CP) and lactate were assayed in the tongue attached gingiva of dogs. The G6P content was found to be significantly higher, and both the ATP and CP contents even more significantly higher in the tongue than in the attached gingiva. Lactate content was not significantly different in the gingiva and in the tongue. The changes in the concentrations of G6P, ATP, CP and lactate due to the intravenous infusion of isoproterenol hydrochloride (1 micrograms/kg/min) were as follows. In the tongue, G6P exhibited a significant increase, but the decrease in ATP and CP contents as well as the increase in lactate content were not significant. It is possible that these effects were the result of the activation of beta-adrenergic receptors by isoproterenol. In the attached gingiva, there was no significant change in the G6P, ATP, or CP content. Lactate increased to a greater degree than the other three components, but similarly did not reach the significant level.

Adenosine Triphosphate↗
PubMed1979

[Semi-automatic assay of post-heparin plasma lipoprotein lipase activity (author's transl)].

A simple method for the assay of post-heparin plasma lipoprotein lipase activity is described. The substrate was a stable intralipid solution. The amount of fatty acids released in the 37 degrees C incubation medium was measured several time during the reaction course, by light absorption on a Technicon auto-analyzer. By plotting these values on a graph paper, the curve of the post-heparin plasma lipoprotein lipase activity was obtained.

Autoanalysis↗
PubMedDate not supplied

Induction of hyperlipemia by carbohydrate-rich fractions isolated from crude papain.

A hyperlipemia was obtained in rabbits injected intravenously with two carbohydrate-rich fractions isolated from crude papain dialyzate. The fractions have an approximative molecular weight of 15,000 and 5,000 daltons and contains 35% and 15% of sugars respectively. The hyperlipemia appears 20 hours after the injection and consists in a hypertriglyceridaemia as suggested by the enrichment of serum in very light lipoproteins of density about 1.006. Concomittantly a decrease of the post-heparin lipase activity (PHLA) of the plasma was observed. After a few days the hyperlipemia disappears and the PHLA returns to a normal value. It is suggested that the hypertriglyceridaemia can be due to an inhibitory effect of the injected fractions on the removal action of the lipases which are released into the blood by an heparin injection.

Animals↗
PubMedDate not supplied

[Diazepam (valium) in premedication. Experimental findings].

The anxiolytic and analgesic effects of 10 mg of orally administered diazepam (Valium) were assessed on 10 volunteers. The electrodermal activity was recorded during two experimental sessions while cutaneous electrical stimulations were administered to the subjects. On one hand, the anxiolytic activity of diazepam could be observed by a decrease of both autonomic nervous system and anticipatory activities. On the other hand, an increase of the pain threshold could be shown under diazepam by lower responses to the stimulations. These results confirm that diazepam can be useful in anxious patients undergoing dental procedures.

Administration, Oral↗
PubMedDate not supplied

Analgesic property of white noise: an experimental study.

The analgesic property of white noise was assessed in 100 healthy volunteer students. Each of them was asked to self administer electrical square wave impulses in order to determine 3 physiological parameters of pain sensation: perception threshold, pain threshold and pain tolerance. These measurements were first performed without any acoustic stimulation and then with a 100 dB white noise. The results showed that the 3 thresholds were significantly increased under white noise. However, the relatively lower average increase obtained for pain threshold and tolerance compared to the perception level, and the great variability of the analgesic efficiency of white noise among subjects, show that this analgesic process is not reliable enough to be useful in medical or dental practice.

Acoustic Stimulation↗
PubMedDate not supplied

Influence of sex and anxiety on pain threshold and tolerance.

The influence of sex and anxiety on experimental pain perception was studied in a homogeneous population of 50 volunteer and healthy dental students. Three threshold (minimum perceptible threshold, pain threshold and pain tolerance threshold) were determined by delivering electrical stimulations, at regular intervals, on the left hand finger pads. At the same time, the students were asked to complete the Cattell's anxiety test, so allowing their degree of anxiety to be quantified. Statistical analysis of the results showed a lower pain tolerance threshold in females than in males and a significant correlation between the anxiety score and the pain tolerance threshold. The fact that females are more anxious than males could explain these results.

Adult↗