Richard E. Behrman

Thalidomide: Effect upon Pregnancy in the Rhesus Monkey

Thalidomide was administered to 44 female rhesus monkeys immediately after they had mated. There were no live births from these animals, whereas there were 11 live births in 57 untreated monkeys. The results are statistically significant. The hypothesis is advanced that thalidomide killed the embryo prior to implantation.

The normal changes in mass and water content in fetal rhesus monkey and placenta throughout gestation

Thirty-eight healthy pregnant rhesus monkeys and their fetuses were studied at different stages of gestation in order to characterize the normal changes in total weight and water content of the fetus and placenta of one of the higher primates. The per cent of total body water in the fetus decreases linearly from 93.1 per cent at 40 days gestation to 74.8 per cent at 158 days gestation (term). The percentage of the total water content in the placenta decreases through the first half of gestation and thereafter remains constant; it is greater than the percentage of total water in the fetus throughout the latter half of pregnancy. The changes in per cent of water content of several body fluids and of fetal liver are also presented. The data provide the bases for further studies of the forces that lead to the accumulation of a net quantity of water in the fetus during a normal gestation.

Changes in amniotic fluid total solute concentration in the rhesus monkey

Abstract Total solute concentrations of the amniotic fluid and maternal plasma from 52 rhesus ( Macaca mulatta ) monkeys in various stages of pregnancy are reported. The mean amniotic fluid total solute concentration was 293.6 ± 7.0 mOsm. per kilogram of water from 40 to 90 days gestation and 280.6 ± 4.7 mOsm. per kilogram of water from 90 to 158 days gestation; and that of maternal plasma was 297.0 ± 6.6 mOsm. per kilogram throughout gestation. The relevance of these observations to the possible mechanism of formation of amniotic fluid is discussed. Total amniotic fluid volumes of ten animals at various gestational ages are reported. The volumes increased to a value of 20 ml. per kilogram of maternal weight at 112 days gestation, and then decreased as pregnancy approached term.

Changes in amniotic fluid volume and total solute concentration in the rhesus monkey following replacement with distilled water

Abstract Changes in amniotic fluid total solute composition and volume in the rhesus monkey following replacement of this fluid with equal volumes of distilled water are described. Initial reduction of total solute concentration of this fluid was rapidly corrected over the next 18 to 20 hours. This correction was achieved by a combination of net transfer of water out of the amniotic fluid compartment and of net transfer of solute, principally sodium and corresponding anions, back into the sac. 131 I-albumin dilution is shown to be a reliable method for measuring amniotic fluid volume in the rhesus monkey. The range of measured volumes increases with gestational age; no other meaningful correlation is seen in the data obtained.

Ontogeny of Soluble and Mitochondrial Tyrosine Aminotransferases

The development of the soluble and mitochondrial forms of tyrosine aminotransferase was observed in fetal and neonatal rhesus monkey tissues. The mitochondrial activity is detectable in early fetal life; the soluble form reaches significant activity just before the birth of the animal.