Amniotic fluid volumes in normal pregnancies

Queenan, John T.; Thompson, William C.; Whitfield, C. R.; Shah, Saroj I.

doi:10.1016/0002-9378(72)90285-2

Cited by 151 publications

(54 citation statements)

References 13 publications

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“…Inasmuch as the amniotic fluid protein concentration remains relatively constant from 32 wk to term, the SP-A data from 32 wk to term appear to be valid regardless of amniotic fluid volume. It is known that the amniotic fluid volume in the human decreases during the last 10 wk of gestation (29). This may account, in part, for the slightly steeper rate of SP-A increase observed after 30-32 wk of gestation when expressed per ml amniotic fluid, although as pointed out by Nelson and Nelson (30), changes in amniotic fluid volume from 30-39 wk of gestation have minor effects on surfactant concentration measurements.…”

Section: Resultsmentioning

confidence: 95%

The Concentration of the 35-kDa Surfactant Apoprotein in Amniotic Fluid from Normal and Diabetic Pregnancies

et al. 1988

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ABSTRACT. A specific, enzyme-linked immunoabsorbent assay was used to determine the concentration of the 35,000 mol wt surfactant apoprotein (SP-A) in samples of amniotic fluid obtained from nondiabetic (n = 358) and diabetic (n = 29) women. The enzyme-linked immunoabsorbent assay was performed with rabbit antibodies directed against SP-A present in lavage fluid from a patient with alveolar proteinosis. Amniotic fluid SP-A concentrations increased as a function of gestational age, from <3 jtg/ml at 30-31 wk to 24 pg/ml at 40-41 wk, and were positively correlated with the lecithin to sphingomyelin ratio ( p < 0.01). SP-A concentrations also increased as a function of gestational age in shake test positive samples ( p < 0.05), but were unchanged in shake test-negative samples. There was no difference in the surfactant apoprotein concentration of male compared with female fetuses at any gestational age. In amniotic fluid obtained from 20 diabetic women, SP-A levels were significantly less than in nondiabetic pregnancies that were matched for gestational age and sex of the fetus ( p < 0.05). The SP-A concentrations in amniotic fluids obtained from nine women who were diabetic and hypertensive and from 10 hypertensive women were not different from matched controls. The relationships described above were valid whether the SP-A concentration was expressed per mg protein or per ml amniotic fluid. These data are suggestive that the concentration of amniotic fluid SP-A is decreased in diabetic pregnancies. (Pediafr Res 24: 728-734, 1988)

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Section: Resultsmentioning

confidence: 95%

The Concentration of the 35-kDa Surfactant Apoprotein in Amniotic Fluid from Normal and Diabetic Pregnancies

et al. 1988

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“…Similarly to what had been observed in mice, the change in the number of KL cells over the course of gestation was reminiscent of a Gaussian curve. By taking into account the volume and cellularity of AF, 29,30 we estimated that the total hAFKL cell number increased up to a peak of 90 ϫ 10 4 after 20 weeks of amenorrhea ( Figure 1D). …”

Section: Resultsmentioning

confidence: 99%

Human and murine amniotic fluid c-Kit+Lin− cells display hematopoietic activity

Ditadi

Coppi

Picone

et al. 2009

Blood

140

115

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We have isolated c-Kit IntroductionDefining the embryonic origin of mammalian hematopoietic stem cells (HSCs) is important for several reasons: understanding how specific adult cell lineages develop, uncovering the pathophysiology of inherited diseases of the hematopoietic system, and developing new, HSC-based therapeutic strategies. The process of blood cell development in the mammalian conceptus is particularly complex, as it occurs at least in 3 sites separated in both space and time: the yolk sac (YS), the para-aortic splanchnopleure and aorta-gonad-mesonephros (AGM) region, and the chorioallantoic placenta. 1,2 Cells with hematopoietic activity can be further distinguished on the basis of their functional properties, as defined by their ability to give rise to all the blood cell lineages in vitro and/or in vivo in either newborn or adult mice.In the mouse, the first definitive repopulating HSCs are found at approximately embryonic day (E) 9.0 in the dorsal aorta and in the YS and at approximately E10 in the vitelline, the umbilical arteries, and the placenta. [3][4][5][6][7][8][9][10] Given that the circulatory system is already established at E8.0 to E8.25, 11 even though not fully functional until E10, 12 the question of whether regions other than the dorsal aorta 4 represent sites of de novo generation of HSC has, until very recently, been subject to much debate. The work performed by Rhodes et al in embryos lacking a circulatory system now suggests that the placenta may correspond to a true site of HSC generation and expansion. 10 These recently published findings still require further investigation to fully define the in vivo functional activity of this hematopoietic site in the absence of circulation because it is well known that prospective hematopoietic cells are influenced by morphogens and factors produced by the immediate environment. 1 Strikingly, there are close interactions between the mesoderm of each known hematopoietic site and the endoderm (in the bilaminar YS), trophectoderm (in the placenta), and the dorsal ectoderm and ventral endoderm (in the AGM region). 1 These close layers probably provide signaling molecules, including vascular endothelial growth factor, basic fibroblast growth factor, and transforming growth factor-␤1, which are essential for the hematopoietic specification of the mesoderm 13 via the controlled expression of key hematopoietic transcriptions factors such as Gata2 and Runx1. Indeed, both Gata2-and Runx1/Aml1-deficient mice present a complete absence of definitive HSCs in the AGM, whereas YS hematopoietic progenitors are still present (albeit in low numbers, in the case of the GATA2 deficiency 1 ). Indeed, LMO2, GATA2, and SCL were shown to bind to the conserved E regions of the Runx1 locus, inducing its transactivation and the expression of Runx1 14 transcription factor that marks the onset of definitive hematopoiesis. 15,16 Whether human and murine hematopoietic systems have the same extra-and intraembryonic sites is still unknown. In humans, cells with hemogenic p...

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“…Amniotic fluid volume averages 500 ml at 20 weeks of fetal development to 1000 ml at 33 weeks and slightly less at term in normal singleton pregnancies. 12 The normal fetus swallows frequently, and contrast medium can be seen in the stomach within 30 minutes by the 16th gestational week (and perhaps earlier). The small intestine occupies a larger portion of the fetal abdomen, and, owing to its fluid absorbing function, concentrates the contrast agent, improving contrast resolution.…”

Section: Discussionmentioning

confidence: 99%