Brief report: Body water estimates in normally grown baboon neonates

Abstract

Water contents of various body water compartments were estimated within nine hours of birth in 11 preterm and eight term baboon (Papio cynccephalus neonates. Estimated water contents of all body compartments (in ml) increased linearly with birthweight (r = 0.52 to 0.90, P 0.007) andwith gestational age (r = 0.46-0.94, P < 0.05). When body water estimates were expressed in proportion to bodyweight (in mlkg), preterm neonates had significantly larger mean antipyrine space and intracellular water than their term peers. Mean corrected bromide space, interstitial water, plasma volume, blood volume, and red cell volume were similar in preterm and term neonates. Although there are minor differences in body water contents and distribution between baboon and human neonates, baboon data are sufficiently similar to human data to justify using the baboon fetus and neonate as a model for investigations of human development.

Body Water Estimates in Intrauterine-Growth-Retarded versus Normally Grown Baboon Neonates

“…1. Individual values for body water estimates (in ml) in intrautcrine-growth-retarded baboons (triangles) superim posed on the regression line (± 2 Sy.x) for 8 term and 11 pre term normally grown baboons [3,4]. When available, data from 2 additional normally grown term baboons are shown as closed circles.…”

“…The considerable similarities in the anatomy, embryology and physiology of the fetopla cental-uterine units in baboon and man sug gest that the baboon is an ideal animal in grown and growth-retarded human neonates, volumes were strikingly similar for growthwhich to investigate problems of human re productive physiology [1][2][3][4][5][6][7][8][9]. Previous stud ies have shown that estimates of body water content and distribution arc quite similar in normally grown baboon and human neo nates, whether born prematurely or at term, to justify using the baboon fetus and mother as a model for investigations of human chemical development [3,4). In this study, we compared the water content of the var ious body compartments at birth in nor mally grown and intrauterinc-growth-retarded neonates born at term and compared the results to those reported in human neo nates.…”

Dilution Kinetics of Chemicals Used for Estimation of Water Content of Body Compartments in Perinatal Medicine

“…These data led most investigators to select a single blood sample, obtained 3 h after administration of bromide, to calculate the bromide space (23,(29)(30)(31)(32)(33)(34), although there was no evidence that stabilization of plasma bromide concentrations did not occur earlier after intravenous injection. In the past, we chose to use 1 h as a convenient time of sampling in both human and baboon neonates (24,(35)(36)(37)(38)(39)(40)(41). The resulting data for group averages were essentially identical to those obtained with the use of a 3-h sample.…”

Simultaneous Estimation of Neonatal Total Body Water by Antipyrine and H₂¹⁸O Dilution

“…The intraassay coefficient of variation (standard deviation/mean X 100) was 1.8%. The preinjection 8 lsO was subtracted from each of the postinjection 8 I80 and the linear regression equation of 8 lsO vs. time was calculated by the least squares method [7], The 8l8OS was calculated from formulae 1 and 2 [8]: y-intercept plasma antipyrine concentration where P corrected for the proportion of water in plas ma, 0.977 for baboons [10] and 0.962 for lambs. The proportion of water in plasma of lambs was deter mined by desiccating at 100°C a known aliquot of plasma from 6 of the lambs used in this study (mean plasma water ± SD = 0.962 ± 0.013 g/ml).…”