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Biomedical subjects

A Dallaire

Publications and source records attributed to A Dallaire.

8 recordsLinked to original sources
PubMed1986

Polygraphic analysis of the sleep-wake states and the REM sleep periodicity in domesticated pigs (Sus scrofa).

Electrocorticography and concurrent electromyography were used during a total of nineteen 24 hr periods in three juvenile pigs in order to establish the quantitative duration of the sleep-wake states and the REM sleep cycles. Wakefulness (W), drowsiness (DR), slow-wave sleep (SWS) and paradoxical sleep (REM) occupied respectively 46.5%, 15.9%, 26.7% and 10.9% of the 24 hr period. Mean duration of episodes was 4.1 min for DR, 6.2 min for SWS and 3.3 min for REM. Sleep cycles (SC) duration was 13.1 min. Near 80% of the SC were nocturnal. Analysis of variance showed a significant difference between diurnal and nocturnal duration of SC (day less than night), as well as between day-time and night-time duration of DR (day greater than night), SWS (day less than night) and REM (day less than night). A strong negative correlation was also found between the mean duration of SC and the number of SC per day.

Animals↗
PubMed1986

Rest behavior.

Behavioral and physiologic characteristics of sleep are described, with special attention paid to equids. Temporal organization of sleep and environmental influences upon this behavior in horses are reviewed. Anatomic and biochemical bases and function of sleep are discussed briefly.

Animals↗
PubMed1985

Premedication of dogs with acepromazine or pentazocine before euthanasia with carbon monoxide.

Euthanasia of unwanted or sick animals should always be done in a humane manner. This study involving two groups of 12 dogs evaluated a two step method of euthanasia using first acepromazine or pentazocine then inhalation of carbon monoxide. During the experiment, behavioral reactions (anxiety, agitation, vocalization and sphincter relaxation) and physiological parameters (electro-encephalogram, electrocardiogram, arterial blood pressure, respiratory and heart rates and serum cortisol) were monitored. The results showed that both drugs modified many behavioral reactions and physiological changes associated with administration of carbon monoxide. Acepromazine and pentazocine reduced by 25% and 20% respectively the number of dogs that showed vocalization and agitation. In acepromazine premedicated dogs, the duration of these signs was significantly diminished and sphincter relaxation did not occur in more than 50% of cases. Furthermore, with the use of acepromazine, no significant peaks or drastic drops were noticed in the heart and respiratory rates and in the arterial blood pressure. These manifestations are usually related to stress. In light of these results, it is recommended to premedicate dogs with acepromazine before submitting them to euthanasia by carbon monoxide inhalation.

Acepromazine↗
PubMed1985

Evaluation of the arterial blood pressure of dogs by two noninvasive methods.

The determination of the arterial blood pressure was done on 12 healthy mixed breed dogs in both the anesthetized and the conscious state, to evaluate two instruments (Doppler flow detector and infrasonde D4000), in their ability to indirectly determine arterial blood pressure. The coefficients of variation were higher with indirect methods when compared with the results obtained by cannulation. These coefficients were lower with the Doppler flow detector. The correlation study showed that both apparatuses were reliable in most situations. The infrasonde D4000 was more accurate than the Doppler in the conscious animals. However the results showed a lack of precision in hypertensive conscious dogs. The diastolic arterial blood pressure was particularly precise in the case of the anesthetized hypotensive dogs. Its sensitivity allowed it to register muscle movement artifacts. The Doppler flow detector showed less variation and was particularly accurate in both anesthetized and conscious hypertensive dogs. Its sensitivity allowed artifact movement sounds to be detected. The Doppler should be used in quiet surroundings or earphones should be worn by the evaluator. Some form of restraint is needed with the use of both instruments. Even if the correlations with the direct arterial blood pressure values were better with the infrasonde D4000, greater variations were found in the individual readings. The Doppler instrument represents in the hands of the investigators a better instrument for routine monitoring of blood pressure in the dog.

Animals↗
PubMed1979

The effect of atropine on acetylcholine-induced depressor responses in adult domestic fowl.

In pentobarbital-anaesthetized, spontaneously breathing adult chickens, intravenous administration of acetylcholine, histamine and 5-HT produced a dose-related fall in carotid arterial pressure, rise in central venous pressure and highly variable effects on heart rate. Atropine at low doses (0.1 to 0.2 mg/kg) selectively antagnoized depressor-responses to acetylchline. The blockade persisted for 20 to 30 min. At medium doses (0.5 to 2 mg/kg) atropine strongly antagonized acetylcholine for 50 to 110 min, and also partially antagonized responses to 5-HT and histamine. At higher doses (6 mg/kg), atropine-induced cholinergic blockade persisted for 280 min. It also nonselectively and significantly blocked responses to histamine and 5-HT. Therefore, it is concluded that the effectiveness and persistence of cholinergic blockade in chickens depends upon the dose of atropine used. It seems to rule out the opinion that high doses of atropine are required for cholinergic blockade in chickens.

Acetylcholine↗
PubMed1974

Sleep and wakefulness in the housed pony under different dietary conditions.

For several weeks, three ponies kept in an environment with controlled light and temperature, were studied for behaviour (time spent in recumbency and time required to consume hay or oats) and for electrical activity of the brain (cortical and sub-cortical) during the night phase of the circadian rhythm. Recumbency was adopted by all the ponies for six or seven periods during the night. With a regimen of hay ad libitum, about four hours were cumulated in sternal recumbency and only one hour in complete lateral recumbency. Various degree of sleep, as identified by cortical and hippocampal electrical activities, accounted for 30% of the circadian cycle. Paradoxical sleep was calculated to occur during 7% of the 24 hours. When oats were substituted for hay or during fasting for two to five days, the total recumbency time and the total sleep time (slow wave sleep and paradoxical sleep) increased. The time in lateral recumbency did not change.

Animal Feed↗