CELLULAR GROWTH IN HUMAN PLACENTA

PEDIATRICS ◽  
1967 ◽  
Vol 39 (2) ◽  
pp. 248-251
Author(s):  
Myron Winick ◽  
Anthony Coscia ◽  
Adele Noble
Keyword(s):  
Cell Division ◽  
Protein Content ◽  
Human Placenta ◽  
Normal Values ◽  
Cellular Growth ◽  
Base Line ◽  
Rate Of Increase ◽  
Normal Human ◽  
Total Dna ◽  
Human Placentae

Fifty normal human placentae from various gestations were analyzed for total DNA, RNA, and protein content. The data indicate that, although weight, RNA, and protein continue to increase linearly until term, the rate of increase in DNA rapidly declines when the placenta reaches about 300 gm or the fetus 2,300 gm. When these data are interpreted in terms of number and size of cells they suggest that cell division stops in human placenta about 1 month prior to term. The latter portion of placental growth is by enlargement of already existing cells. These data establish normal values for human placenta from 26 through 42 weeks and provide a base line to compare placentae of abnormal pregnancies.

HYDROXYSTEROID DEHYDROGENASE ACTIVITY IN NORMAL HUMAN PLACENTA FROM SIX WEEKS TO FORTY-TWO WEEKS OF GESTATION

1966 ◽  
Vol 35 (3) ◽  
pp. 255-NP ◽  
Author(s):  
D. McK. HART
Keyword(s):  
Dehydrogenase Activity ◽  
Human Placenta ◽  
Age Distribution ◽  
Hydroxysteroid Dehydrogenase ◽  
Villous Trophoblast ◽  
Normal Human ◽  
Human Placentae

SUMMARY Fifty-two normal human placentae from the 6th to the 42nd week of pregnancy were surveyed for 3α-, 3β-, 6β-, 11α-, 11β-, 12α-, 16α-, 16β-, 17α-, 17β-, 20β-, 21- and 24-hydroxysteroid dehydrogenase (HSD) activities. Strong NAD-linked 3β-, 16β-, and 17β-HSD activities and moderate NADP-linked 3β-, 16β- and 17β-HSD activities were found in the villous trophoblast at all ages. Weak 3α- and weak or trace 6β- and 11β-HSD activities were found in the trophoblast of some placentae using NAD as cofactor, with no obvious age distribution. Moderate 17β-HSD activity, NAD-linked only, was found in the villous stroma and vasculature.

Cellular growth in several organs of normal and dwarfed Snell mice

1982 ◽  
Vol 99 (1) ◽  
pp. 141-149 ◽  
Author(s):  
Sylvia van Buul-Offers ◽  
Jan Leo Van den Brande ◽  
L. Dumoleijn ◽  
M. Feijlbrief ◽  
P. L. M. van de Klundert
Keyword(s):  
Cell Division ◽  
Protein Content ◽  
Salivary Glands ◽  
Cell Size ◽  
Cellular Growth ◽  
Cell Enlargement ◽  
Normal Range ◽  
Submandibular Salivary Glands ◽  
Snell Dwarf ◽  
Dwarf Mice

Abstract. The DNA, RNA and protein content of different organs was studied in Snell dwarf mice and compared with unaffected controls at different ages. The following organs were included: liver, kidneys, heart, submandibular salivary glands, spleen and thymus. In normal mice the rapid post-natal growth of all these organs is due to cell division and in the liver, kidneys, heart and submandibular salivary glands to cell enlargement as well. In dwarf mice weight of most organs studied is comparable with that of 1–2 weeks old normals. The data suggest no differences in cell size between dwarfs and normals in the liver, submandibular salivary glands, spleen and thymus, irrespective of age. In contrast, cell size of the heart and kidneys remains below the normal range and the RNA content is lowered as well. RNA is also low in the submandibular salivary glands and the liver, despite their normal protein content.

Ex ‐ Vivo MRI of the Normal Human Placenta: Structural–Functional Interplay and the Association With Birth Weight

2021 ◽  
Author(s):  
Daphna Link‐Sourani ◽  
Netanell Avisdris ◽  
Shaul Harel ◽  
Liat Ben‐Sira ◽  
Tuvia Ganot ◽  
...  
Keyword(s):  
Birth Weight ◽  
Human Placenta ◽  
Ex Vivo ◽  
Normal Human

Human placental vitamin B6 (pyridoxal) transport: normal characteristics and effects of ethanol

1992 ◽  
Vol 262 (6) ◽  
pp. R966-R974 ◽  
Author(s):  
S. Schenker ◽  
R. F. Johnson ◽  
J. D. Mahuren ◽  
G. I. Henderson ◽  
S. P. Coburn
Keyword(s):  
Human Placenta ◽  
Binding Sites ◽  
Vitamin B6 ◽  
Passive Transport ◽  
Short Term ◽  
Placental Transport ◽  
Normal Human ◽  
Important Form ◽  
Composite Data ◽  
In Pregnancy

The aims of this study were to define normal human placental transport of pyridoxal, an important form of vitamin B6 in pregnancy, and to determine the effect of short-term alcohol on this process. Our studies used the isolated single cotyledon from the term placenta. Pyridoxal crossed the human placenta readily in both directions, but the transfer was a little less than half that of antipyrine and was significantly greater in the direction of the fetus. Pyridoxine appeared to have a similar clearance from the maternal compartment as pyridoxal, but transport of intact pyridoxal 5'-phosphate was much smaller. There was no saturable transfer of pyridoxal, and it was not transferred from the maternal to fetal compartments against a concentration gradient. Placental concentration of pyridoxal exceeded both maternal and fetal perfusate pyridoxal concentrations, but this concentration was equal for both perfusion directions. These composite data are most suggestive of passive transport of pyridoxal across the placenta, binding of the vitamin in the placenta as an explanation for its concentration there, and greater phosphorylation of pyridoxal in the placenta when the compound is transferred in the fetal direction, possibly displacing pyridoxal from its binding sites and permitting its greater release into the fetal compartment. Alcohol, 400-250 mg/dl over 2.5 h, inhibited the transport of pyridoxal from the maternal to fetal compartments by approximately 42% (P = 0.03) and resulted in a lower transfer of pyridoxal 5'-phosphate into the fetal perfusate (P = 0.02).

scholarly journals Effect of microinjection of a low-Mr human placenta protein tyrosine phosphatase on induction of meiotic cell division in Xenopus oocytes.

1990 ◽  
Vol 10 (2) ◽  
pp. 458-463 ◽  
Author(s):  
N K Tonks ◽  
M F Cicirelli ◽  
C D Diltz ◽  
E G Krebs ◽  
E H Fischer
Keyword(s):  
Cell Division ◽  
Insulin Receptor ◽  
Human Placenta ◽  
Protein Tyrosine Phosphatase ◽  
Xenopus Oocytes ◽  
Tyrosine Phosphatase ◽  
Meiotic Cell ◽  
Protein Tyrosine ◽  
Endogenous Activity ◽  
Maturation Promoting Factor

Homogeneous preparations of a protein phosphatase that is specific for phosphotyrosyl residues (protein tyrosine phosphatase [PTPase] 1B) were isolated from human placenta and microinjected into Xenopus oocytes. This resulted in an increase in activity of up to 10-fold over control levels, as measured in homogenates with use of an artificial substrate (reduced carboxamidomethylated and maleylated lysozyme). Microinjected PTPase was stable for at least 18 h. It is distributed within the oocyte in a manner similar to the endogenous activity and is suggestive of an interaction with cellular structures or molecules located predominantly in the animal hemisphere. The phosphatase markedly retarded (by up to 5 h) maturation induced by insulin. This, in conjunction with the demonstration that PTPase 1B abolished insulin stimulation of an S6 peptide (RRLSSLRA) kinase concomitant with a decrease in the phosphorylation of tyrosyl residues in a protein with the same apparent Mr as the beta subunit of the insulin and insulinlike growth factor 1 receptors (M. F. Cicirelli, N. K. Tonks, C. D. Diltz, E. H. Fischer, and E. G. Krebs, submitted for publication), provides further support for an essential role of protein tyrosine phosphorylation in insulin action. Furthermore, maturation was significantly retarded even when the PTPase was injected 2 to 4 h after exposure of the cells to insulin. PTPase 1B also retarded maturation induced by progesterone and maturation-promoting factor, which presumably do not act through the insulin receptor. These data point to a second site of action of the PTPase in the pathway of meiotic cell division, downstream of the insulin receptor and following the appearance of active maturation-promoting factor.

scholarly journals Properties of sulfatides in factor-XII-dependent contact activation

Blood ◽  
1982 ◽  
Vol 59 (1) ◽  
pp. 69-75 ◽  
Author(s):  
G Tans ◽  
JH Griffin
Keyword(s):  
Normal Values ◽  
Limited Proteolysis ◽  
Factor Xii ◽  
Contact Activation ◽  
Amidolytic Activity ◽  
Prolonged Incubation ◽  
Coagulant Activity ◽  
Plasma Factor ◽  
Normal Human ◽  
Kallikrein Activity

Abstract Incubation of normal human plasma with low amounts of sulfatides resulted in the initiation of intrinsic coagulation and the appearance of kallikrein activity. The optimal initiation of procoagulant and kallikrein amidolytic activity was dependent on the presence of factor XII, high molecular weight kininogen, and prekallikrein. Since the activated partial thromboplastin clotting times in prekallikrein- deficient plasma approach normal values upon prolonged incubation with kaolin, this phenomenon of autocorrection was studied and found to be even more pronounced in the presence of sulfatides. Autocorrection was essentially completed in 5 min in the presence of sulfatides, whereas a preincubation of 15–20 min was required in the presence of kaolin. The limited proteolysis of 125I-factor XII in plasma during incubation with activating material or during clotting was determined. Cleavage of factor XII was more rapid and more extensive in the presence of sulfatides than in the presence of kaolin. In prekallikrein-deficient plasma, factor XII cleavage was completed within 5 min in the presence of sulfatides and within 15 min in the presence of kaolin. Thus, the appearance of factor-XII-dependent coagulant activity correlates with the limited proteolysis of factor XII when normal or prekallikrein- deficient plasma is activated by sulfatides or kaolin.

EFFECT OF PREGNANCY ANAEMIA ON CELLULAR GROWTH IN THE HUMAN PLACENTA

2008 ◽  
Vol 68 (6) ◽  
pp. 899-901 ◽  
Author(s):  
PURNIMA MARWAH ◽  
P. N. SINOLA ◽  
MEENAKSHI KRISHNA ◽  
K. N. AGARWAL
Keyword(s):  
Human Placenta ◽  
Cellular Growth
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