Gilbert J. Vosburgh

The rate of renewal in woman of the water and sodium of the amniotic fluid as determined by tracer techniques

Abstract The rate of passage of water and sodium from the maternal circulation to the amniotic fluid has been measured with heavy water and radioactive sodium as the tracer substances. The water of the fluid is completely replaced on the average once every 2.9 hours; this considerable rate of turnover is at variance with the concept that the amniotic fluid is stagnant. The rate of transfer of water is about five times more rapid than that of sodium.

The estimation of extracellular and total body water in the newborn human infant with radioactive sodium and deuterium oxide

Summary On the basis of dilution of a known quantity of intravenously injected sodium chloride tagged with a radioactive isotope of sodium, the extracellular fluid volume in three newborn human infants has been found to average 43.5 per cent of the body weight. Similar measurements with deuterium oxide gave a volume of total body water equal to 74.6 per cent of body weight.

The permeability of the human placenta to water and the supply of water to the human fetus as determined with deuterium oxide.

Abstract 1. 1. Changes in permeability of the human placenta to water have been measured with deuterium oxide as the tracer material from the fourteenth week of pregnancy until term. There is about a fivefold increase in transfer rate of water per unit weight of placenta during this period. 2. 2. The placental transfer coefficient for water is five times as great as that for sodium at corresponding periods of gestation. 3. 3. The permeability of the placenta of the guinea pig to water has been found to be about twice that of the human placenta; this divergence is considerably greater than for sodium. 4. 4. The human fetus receives across the placenta at the fourteenth week of gestation 700 times and at the thirty-first week 3,800 times as much water as is incorporated in the growing tissues.