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Biomedical subjects

S Cassin

Publications and source records attributed to S Cassin.

At least 73 records · Page 4Linked to original sources
PubMed1977

Heat production of fetal sheep brain in utero.

Thermojunctions were implanted in the brains of 10 near term fetal sheep in utero under halothane anesthesia. Brief total occlusion of fetal brachiocephalic artery was followed immediately by an increase in brain temperature (mean +/- SE) of 0.130 +/- 0.014 degrees C-min-1. Occlusion of main pulmonary artery and ascending aorta, simultaneously, led to a brain temperature increase of 0.144 +/- 0.018 degrees C-min-1. Specific heat of three fetal brains was determined to be 0.898 +/- 0.014 cal-g-1. degrees C-1 or 3.76 +/- 0.059 J-g-1. Rate of fetal brain heat production, computed as the product of the higher rate of temperature change and brain specific heat, was 0.129 +/- 0.014 cal-g-1-min-1 or 9.00 +/- 0.98 mW-g-1.

Animals↗
PubMed1977

Prostaglandins and regulation of the pulmonary circulation in the perinatal period.

Effects of indomethacin on pulmonary vasodilation caused by ventilation of the fetal lungs with air were evaluated in anesthetized, exteriorized fetal goats by means of an open-chest pump perfused lung preparation. When fetal lungs are ventilated with air, pulmonary vascular resistance decreases in two steps: 1) a rapid decrease in pulmonary vascular resistance during the first 30 seconds of ventilation, and 2) a slower decline which continues through the first 10-20 minutes of more of ventilation. Indomethacin has minimal effect upon the first component. The second component is absent following treatment with indomethacin. Effects observed with indomethacin were more pronounced in immature fetuses (less than 90% gestation), than in mature fetuses. Prostaglandin synthetase activity appears to have a role in the pulmonary vasodilation resulting from ventilation of the fetal lungs with air.

Animals↗
PubMed1976

Use of indomethacin to reverse neonatal hypotension.

Treatment with indomethacin elevated systemic arterial pressure and pulmonary vascular resistance in hypotensive newborn goats. Indomethacin may be of value in restoration of systemic arterial pressure in stress-induced hypotension.

Animals↗
PubMed1976

Maturation of contractile response of ductus arteriosus to oxygen and drugs.

Contractile responses of rings of ductus arteriosus from fetal and neonatal guinea pigs were studied in buffered Krebs-Henseleit solutions of various oxygen tensions. Oxygen-induced contraction of ductus arteriosus increased with gestational age, peaking at term and attenuating within 24 h after birth. Contractions of ductus in response to potassium were not different in term and preterm fetuses. Maximal contractile response of pre- and postductal aortic rings to oxygen was 8.3% of the maximal oxygen-induced contraction of ductal rings from the same fetuses. Pulmonary artery was quite insensitive to oxygen. Of 12 ductus exposed to bradykinin in the absence of oxygen seven contracted (maximal response was obtained with 15.0 ng/ml). Exposure of ductus to bradykinin in the absence of oxygen enhanced subsequent contractions of ductal smooth muscle rings to air. Atropine failed to inhibit the oxygen-induced contraction of ductus. These data suggest that acetylcholine is not essential for oxygen-induced contraction of the guinea pig ductus arteriosus.

Acetylcholine↗
PubMed1975

Effects of prostaglandins of the E-series on pulmonary and systemic circulations of newborn goats during normoxia and hypoxia.

Effects of exogenous prostaglandins of the E-series on pulmonary and systemic circulations of newborn goats were investigated during normoxia and hypoxia. Pulmonary arterial infusion of prostaglandins E1 and E2 decreased pulmonary vascular resistance 20% and 14%, respectively, without systemic effects. Prostaglandin E1 abolished the pulmonary pressor response to hypoxia. Prostaglandin E2 was less effective in counteracting this hypoxic response. The increased pulmonary vascular resistance and augmented response to hypoxia following indomethacin administration was reversed by prostaglandin E1. Infusion of prostaglandin E1 directly into the pulmonary circulation may be of benefit to the distressed newborn with elevated pulmonary vascular resistance.

Animals↗
PubMed1975

The effects of prostaglandin E on fetal pulmonary vascular resistance (38588).

The effects of PGE on pulmonary vascular resistance were investigated in fetal goats using an isolated perfusion technique on otherwise intact unventilated lobes. PGE decreased perfusion pressure in the left pulmonary artery under conditions of monary vascular resistance by vasodilatation of tonically contracted vascular smooth muscle. In our preparation, intrapulmonary PGE infusion did not alter femoral arterial pressure which suggests that PGE is inactivated in the fetal lung. Implications for PGE in the newborn with respiratory distress and increased pulmonary vascular resistance are discussed.

Animals↗
PubMed1975

The effects of indomethacin on the pulmonary vascular response to hypoxia in the premature and mature newborn goat.

The effects of indomethacin on the pulmonary circulation and the response of the circulation to hypoxia were investigated in premature and mature newborns using an isolated perfusion technique on otherwise intact left lungs in situ. There was an increase in pulmonary vascular resistance and augmentation of the increase in pulmonary vascular resistance during hypoxia following indomethacin. These effects were greater in the premature than in the mature newborn. Indomethacin effectively removes a dilator influence on the pulmonary circulation. The results are consistent with the concept that prostaglandins are important in regulating pulmonary vascular resistance.

Animals↗
PubMed1975

Electrolyte and acid-base status of aqueous humor in perinatal and adult goats.

These experiments were undertaken to determine electrolyte concentration and acid-base status of aqueous humor and arterial plasma H2O in perinatal and adult goats. The distribution of potassium, sodium, chloride, magnesium, and calcium between aqueous humor and plasma H2O in fetal, neonatal, and adult goats changed independently with age and could not be explained by passive Gibbs-Donnan equilibria. Anterior chamber aqueous humor has a reduced pH, PO2, HCO3-, and an elevated PCO2 compared to arterial blood in the neonate and adult.

Acid-Base Equilibrium↗