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Biomedical subjects

A Dandavino

Publications and source records attributed to A Dandavino.

18 recordsLinked to original sources

Hodgkin's disease complicating pregnancy.

We report our experience in the management of 12 patients with Hodgkin's disease associated with pregnancy. Three patients presented in the first trimester; pregnancy was interrupted in two. They are alive and well after 8, 14 and 16 years of follow-up. Two patients presented in the second trimester; they elected to continue their pregnancies and both died from progressive disease, one of them having refused therapy. The remaining seven patients in the third trimester continued pregnancy; they are all alive after five to 11 years of follow-up and one is alive with active disease. Two patients received radiotherapy during pregnancy. Both had normal outcomes of pregnancy and no fetal abnormalities were found. There is no evidence to suggest that either pregnancy affects the course of Hodgkin's disease or that Hodgkin's disease affects pregnancy. General rules as to how to proceed in patients with Hodgkin's disease complicated by pregnancy are described.

Adult↗

Systemic and uterine hemodynamic responses to dopamine in pregnant and nonpregnant sheep.

The systemic and uterine hemodynamic effects of dopamine were studied in nonpregnant and near-term pregnant, unanesthetized, chronically instrumented sheep. Dopamine was administered by constant intravenous infusion in doses ranging from 2 to 40 microgram per kilogram per minute. A hypertensive effect was consistently observed when doses greater than 5 microgram per kilogram per minute were given. The rise in pressure was accompanied by a rise in the systemic vascular resistance and an increase in the cardiac output; the increment in the latter was greater in the pregnant than in the nonpregnant animals. Uterine blood flow increased consistently despite some rise in uterine vascular resistance; uterine fraction of cardiac output either remained unchanged or increased slightly. Venomotor construction, reflected by a rise in central venous pressure, occurred at all dose levels. These hemodynamic properties of dopamine may be explained partly on the basis of its combined beta- and alpha-mimetic action, as well as through redistributions of flows and resistances among various regional vascular beds.

Animals↗

Influence of jejunoileal bypass on protein metabolism during pregnancy.

Management of the pregnant patient who has undergone operation for jejunoileal bypass poses many problems for the attending obstetrician. Several recent studies have broadened our knowledge of this group of patients. Unfortunately, the significance of this form of weight loss upon the developing fetus is at best only poorly understood. In our study, amino acid chromatography was performed at 34 weeks' gestation and at delivery in order to assess the impact of this procedure upon maternal and fetal (cord blood) amino acid concentrations. Results suggest that protein metabolism in the patient who has had intestinal bypass without resulting complications and in her fetus is comparable to that in normal pregnancy. Altered amino acid profiles were observed in one twin gestation and in one patient who continued to lose weight throughout pregnancy. The significance of these observations is discussed with respect to the relationship of protein deprivation to neonatal development.

Adult↗

Cardiac output changes during neonatal growth.

Changes in resting cardiac output (CO), stroke volume (SV), and systemic vascular resistance (SVR) during neonatal growth were studied in chronically instrumented lambs from the 1st to 5th wk of age; adult nonpregnant sheep values measured simultaneously were used as standard reference. Neonatal responses to autonomic agonists and antagonists were also investigated. Total CO increased linearly with neonatal growth, but decreased strikingly when expressed per weight unit; at 5 wk of age, CO/kg was still significantly higher than the adult value. SV also increased with neonatal growth but did not change when related to body weight; at 5 wk of age, SV/kg values were still higher than those of adult sheep. SVR changed reciprocally to CO. The decrease in CO/kg during neonatal growth paralleled the progressive decline in heart rate (HR). Beta receptor stimulation increased neonatal CO markedly and the increment was the same from the first through the fifth neonatal week. Beta blockade had insignificant effects, but cholinergic blockade produced moderate CO increases.

Aging↗

Cardiovascular reactivity of neonatal and adult sheep to autonomic stimuli during adrenergic depletion.

The cardiovascular responses of the neonatal and adult sheep to autonomic agonists and antagonists were studied in the resting state and following adrenergic neuronal depletion with reserpine. Both the neonates and adults showed similar supersensitivity of the effector system of the peripheral circulation to alpha adrenergic stimulation with catecholamines. In addition, the neonates exhibited supersensitivity of the myocardial effector system to beta-adrenergic stimulation. Unusual finding was a marked supersensitivity of the heart and peripheral circulation to cholinergic receptor blockade with atropine, the mechanisms of which are as yet unclear.

Acetylcholine↗

Development of neurohumoral control of fetal, neonatal, and adult cardiovascular functions.

Neurohumoral control of fetal, neonatal, and adult cardiovascular functions have been reviewed. Resting fetal heart rate remains fairly constant but neonatal heart rate declines progressively, reaching adult levels within six to eight weeks; systemic arterial pressure rises while pulmonary pressure falls to adult levels within the first week after birth. Sympathetic and parasympathetic control of circulatory functions matures at different rates during fetal and neonatal development; the sympathetic system becomes active earlier in fetal life than does the parasympathetic system. After birth, the parasympathetic tone of the resting heart rate rises to adult levels while adrenergic tone decreases. Despite changing autonomic activities, resting heart rate is set at given levels through alterations in intrinsic control. In the fetus, peripheral circulation is under neurohumoral tone of increasing magnitude; after birth, neurohumoral tone declines progressively, reaching levels comparable to those of adult nonpregnant sheep. Fetal cardiovascular response to neurotransmitters increases with age because of maturation of the effector system. The pulmonary bed responds primarily to acetylcholine whereas the systemic circulation responds to norepinephrine. After birth, the neonatal cardiovascular system becomes four to five times more sensitive to the action of neurotransmitters mainly because of closure of vascular shunts and elimination of umbilicoplacental circulation. In the neonate and adult, the pulmonary vascular bed loses its reactivity to neurotransmitters.

Animals↗

Circulatory effects of magnesium sulfate in normotensive and renal hypertensive pregnant sheep.

We have studied the effects of magnesium sulfate (MgSO4) administration in chronically instrumented normotensive and hypertensive pregnant sheep. Animals of 90 to 144 days' gestation were divided in two groups; those with normotensive arterial pressure and those in which renovascular hypertension had been produced. Our results show that bolus injection of 2 or 4 Gm. of MgSO4 caused a transient decrease in systolic and diastolic pressure which returned to control values within 5 to 10 minutes. The continuous infusion of MgSO4 in doses of 2 or 4 Gm. per hour produced a slight increase in uteroplacental blood flow but did not alter the blood pressure. Heart rate showed a slight increase. Because MgSO4 produced no significant hemodynamic changes, we feel that: (1) its use in obstetrics must be based on its anticonvulsant action and (2) MgSO4 in either normotensive or hypertensive patients is not associated with impairment of uteroplacental blood flow.

Animals↗

Action of histamine and H1 and H2 blockers on the cardiopulmonary circulation.

Systemic and pulmonary hemodynamic responses to histamine were investigated inchronically instrumented unanesthetized nonpregnant ewes. Histamine was administered intravenously and into the pulmonary artery. The effects of the same doses of histamine were assessed following H1 and H2 receptor blockade. The effects ocular changes were also monitored. Results indicate that intravenous histamine produces tachycardia, systemic hypotension, pulmonary hypertension, and reduced cardiac output. The pulmonary response could be modified significantly by pentobarbital anesthesia. When injected directly into the pulmonary artery histamine failed to elicit any circulatory response. Blockade of H1 and H2 receptors, as well as autonomic ganglia, resulted in a comparable attentuation of the histamine circulatory response. It is concluded that a) central hemodynamic responses do not seem to be mediated through specific H1 and H2 receptors; b) histamine-induced pulmonary vasoconstriction can be reversed by pentobarbital anesthesia, and c) the absence of circulatory response to intrapulmonary histamine administration suggests that whatever receptors that may exist in the pulmonary vascular bed are not necessary for the central hemodynamic effects.

Animals↗

Autonomic control of cardiovascular functions during neonatal development and in adult sheep.

We studied the autonomic control of resting heart rate of systemic and pulmonary vascular blood pressures (BP) in chronically instrumented neonatal lambs 1-8 weeks of age. The maximum response to ganglionic blockade and sympathetic and parasympathetic antagonists was taken as an index of the magnitude of the total neural, adrenergic, and cholinergic tones. The reactivity of the circulatory parameters to adrenergic and cholinergic agonists also was investigated. All findings were compared with those in adult nonpregnant sheep studied concomitantly and with data previously obtained from term fetal lambs. The results of our studies show: (1) resting heart rate declines spontaneously throughout the 8 weeks of neonatal life approaching that of adult sheep; (2) the progressive bradycardia is not related to changes in the parasympathetic or sympathetic tone; (3) resting systemic BP is under strong neurohumoral control during the first two to three weeks of neonatal life; the control decreases progressively, becoming similar to that of adult sheep; (4) resting pulmonary artery pressure of neonatal and adult sheep has no neurohumoral control; (5) the systemic BP response of the neonate to autonomic agonists is greater than that of the term fetus and is similar to that of the adult; (6) in neonatal and adult sheep, compared to the term fetus, the pressor response to norepinephrine is accompanied by a baroreceptor-mediated bradycardia, and acetylcholine-induced systemci hypotension is accompanied by a "paradoxical" tachycardia mediated through beta-adrenergic stimulation; (7) in contrast to our finding for the fetus, the pulmonary vascular pressure of neonatal and adult sheep is unresponsive to autonomic agonists.

Acetylcholine↗

[Emigration of Quebec physicians: motivation for departure and return].

Since the 80's, outmigration of physicians from Quebec is steadily increasing. About 46 percent of outmigrating doctors explain their move by factors related to their occupational life (higher income, greater opportunity in the academic career, larger amount of resources devoted to the health care system). Nearly 40 percent relate their decision to personal factors (greater job opportunity for their wife/husband, quality of family life...). The factors linked to the context of the receiving place (political climate, linguistic regulations, income tax level...) play a minor role on the migration decision. As concerns the returning physicians, 80 percent explain their decision by personal factors. The factors linked to the occupational life have a lower role. It appears therefore that doctor outmigration from Quebec is not directly determined by manpower policies adopted by the Province during the last two decades, except the policies directly linked to the income level of professionals.

Adult↗

[Beyond the statistics: why are Quebec physicians emigrating?].

During the period 1986-1999, about 16% of the annual average number of active physicians in Quebec have left for the US or an other Canadian province. The absolute number was 2367. During the same period, 661 would have returned to Quebec. The majority of the outmigrating doctors were graduated from the anglophone university of the Province (although 44 percent are francophone) whereas the majority of the returning doctors were graduated from the 3 francophone universities of the Province. As a matter of fact, 78 percent of the returning doctors are francophone. The migration decision is equally linked to post-graduate training and occupational opportunities and job satisfaction. This feature should be related to an other: those who have returned to Quebec have had a geographic and occupational mobility level far lower than those who have not returned. Finally, it is noteworthy that there are significant differences between the doctors emigrating to the US and their colleagues going to an other Canadian province.

Adult↗