Accumulation of Nitrogen and Six Minerals in the Human Fetus During Gestation

Kelly, Harriet J.; Sloan, Ralph E.; Hoffman, W. E.; Saunders, Claribel

doi:10.1097/00006254-195202000-00003

Cited by 13 publications

(17 citation statements)

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“…proportion of body fat, which exceeds the increase of nitrogen content (Widdowson and Spray, 1951;Kelly et al, 1951) (Fig. 6).…”

Section: Weeksmentioning

confidence: 86%

“…Water content of the fetus decreases throughout development from 92-94% of the body weight in a 10-g fetus to 70-72% in a term fetus (Widdowson and Spray, 1951;Kelly et al, 1951). Fetal lipid content changes are opposite to those of water content.…”

Section: Weeksmentioning

confidence: 94%

“…In larger fetuses, fat is accumulated in the various depots at an increasing rate during the last third of pregnancy. Available data on term babies suggest a proportion of body fat ranging from 15 to 30% (Widdowson and Spray, 1951;Kelly et al, 1951) (Fig. 6).…”

Section: Weeksmentioning

confidence: 99%

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Nutrition and Pregnancy

Rosso

Cramoy

1979

Nutrition

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“…proportion of body fat, which exceeds the increase of nitrogen content (Widdowson and Spray, 1951;Kelly et al, 1951) (Fig. 6).…”

Section: Weeksmentioning

confidence: 86%

Section: Weeksmentioning

confidence: 94%

See 1 more Smart Citation

Nutrition and Pregnancy

Rosso

Cramoy

1979

Nutrition

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“…The method given below was used to remove the bias in the data of Widdowson and Dickerson (55), introduced by the unusually large size of their full term fetuses, and to enable us to estimate weight gain and nitrogen retention for fetuses growing along different percentiles. From the data of Widdowson and Dickerson (55) and of Kelly et al (25) it can be shown that nitrogen concentration of the foetus rises in a linear manner between 18 and 40 wk gestation and corresponds to the equation.…”

Section: Intrauterine Weight Gain and The Nitrogen Accumulation Of Fomentioning

confidence: 94%

Nitrogen Metabolism in Preterm Infants Fed Human Donor Breast Milk: the Possible Essentiality of Glycine

et al. 1981

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SummaryNitrogen metabolism was studied in three preterm infants (mean gestation 32 wk) by the method of consecutive metabolic balance. The absorption and retention of nitrogen from breast milk was measured, and protein turnover, synthesis, and breakdown were calculated from isotopic plateau of urinary urea and ammonia using an intermittent oral administration of "N-glycine. Weight gain and nitrogen retention were compared with the weight gain and nitrogen accumulated for a foetus of equivalent gestational age in utero.The average composition of the milk was 289 + 19 K J dl-' and 1.44 + 24 g protein dl-'. The intake of energy was 572 + 61 KJ kg-' day -' and of nitrogen 447 + 99 mg kg-' day-'. Stool output of nitrogen was 100 + 32 mg kg-' day-' giving an absorption of 348 + 78 mg kg-' day-', as urinary excretion was 91 + 17 mg kg-' day-' retained nitrogen was 256 2 71 mg kg-' day-', or 56% of intake.The specific weight gain was 15.6 5 2.6 g kg-' day-' and 53% of this comprised lean tissue (range 34 to 89%). In all but one study the postnatal retention of nitrogen fell far short of calculated in utero accumulation.The results of protein turnover were surprising. In six of the eight studies urinary urea failed to become enriched at all. Protein turnover calculated from the ammonia plateau was 1.94

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“…Below this level there is a net release and above it a net gain in Ca by the lobular tissue. Kelly, Sloan, Hoffman & Saunders (1951) estimate that the term human fetus in vivo gains Ca at a rate of between 95 and 150 mg/day . kg fetal weight.…”

Section: Closed-circuit Studiesmentioning

confidence: 99%

Calcium transport across the isolated dually perfused human placental lobule.

Abramovich¹,

Dacke²,

Elcock³

et al. 1987

The Journal of Physiology

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SUMMARY1. Movements of 45Ca and 3H20 in maternal to fetal (M-4F) and fetal to maternal (F->-M) directions across the dually perfused isolated human placental lobule were measured under steady-state conditions.2. M-IF values of the clearances (CR) and extractions (ER) of 45Ca relative to 3H20 were 0O371+ 0056 and 0492 + 0086 (mean + S.E. of mean) respectively. The corresponding values for F-IM movements were 0-277+0017 and 0251+0-010 respectively. The F-*M perfusion flow ratio (QF/QM) was 0-34+0001 throughout.Comparison with previously published data indicated a significant degree of membrane limitation to Ca transfers.3. There was evidence of a mismatch between tissues receiving a fetal and those receiving a maternal perfusion.4. The relative extraction ER was markedly and reversibly enhanced when perfusate total Ca was reduced from 2-4 to 0-1 mm. The effect was present in both M-IF and F-I.M transfers and provided evidence for carrier-mediated uptake of Ca on both aspects of the placental barrier. Small and transient decreases in the relative clearance CR were observed on changing from 2-4 to 0 1 mm-Ca in M-*F and to a lesser extent F-*M transfers while transient increases were seen on changing from 0.1 back to 2-4 mM-Ca.5. Measurement of net changes in Ca levels in closed-circuit studies indicated a significant release of both ionized (Ca2+) and total (CaT) Ca into the fetal perfusate at total Ringer solution concentrations of 1-4, 1'9 and 2-4 mM-Ca. Release of Ca into the maternal circuit was also observed using 1-4 mM-Ca Ringer solution but when 1-9 and 2-4 mm-Ca Ringer solution was used a net uptake occurred.6. These findings strongly suggest that mechanisms by which Ca is transferred from M-IF circulations in vivo are at least partly preserved in the in vitro human placental preparation. They indicate that this preparation is suitable for the study of these mechanisms and their regulation by hormonal and other factors.

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Accumulation of Nitrogen and Six Minerals in the Human Fetus During Gestation

Cited by 13 publications

References 0 publications

Nutrition and Pregnancy

Nutrition and Pregnancy

Nitrogen Metabolism in Preterm Infants Fed Human Donor Breast Milk: the Possible Essentiality of Glycine

Calcium transport across the isolated dually perfused human placental lobule.

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