Effects of sustained dietary ethanol on the ultrastructure of the visceral yolk-sac placenta of the rat

Teratology ◽  
1990 ◽  
Vol 42 (5) ◽  
pp. 541-552 ◽  
Author(s):  
William P. Jollie
Keyword(s):  
Yolk Sac ◽  
Visceral Yolk Sac ◽  
Yolk Sac Placenta

Visualization of Antibody Transport in Rat Visceral Yolk-Sac Placenta

1982 ◽  
Vol 40 ◽  
pp. 246-247
Author(s):  
William P. Jollie
Keyword(s):  
Phosphate Buffer ◽  
Yolk Sac ◽  
Female Rats ◽  
Thin Sections ◽  
Visceral Yolk Sac ◽  
Antibody Complex ◽  
Cytochemical Reaction ◽  
Hind Foot ◽  
Antigen Antibody ◽  
Yolk Sac Placenta

A technique has been developed for visualizing antibody against horseradish peroxidase (HRP) in rat visceral yolk sac, the placental membrane across which passive immunity previously has been shown to be transferred from mother to young just prior to birth. Female rats were immunized by injecting both hind foot pads with 1 mg HRP emulsified in complete Freund's adjuvant. They were given a booster of 0.5mg HRP in 0.1 ml normal saline i.v. after one week, then bred and autopsied at selected stages of pregnancy, viz., 12, 1 7 and 22 days post coitum, receiving a second booster, injected as above, five days before autopsy. Yolk sacs were removed surgically and fixed immediately in 2% paraformaldehye, 1% glutaraldehye in 0.1 M phosphate buffer with 0.01% CaCl2 at pH 7.4, room temperature, for 3 hr, rinsed 3X in 0.1 M phosphate buffer plus 5% sucrose, then exposed to 1 mg HRP in 1 ml 0.1 M phosphate buffer at pH 7.4 for 1 hr. They were refixed in aldehydes, as above, for 1 5 min (to assure binding of antigen-antibody complex). Following buffer washes, the tissues were incubated in 3 mg diaminobenzidine tetrahydrochloride and 0.01% H2O2 in 0.05 M Tris-HCl buffer for 30 min. After brief buffer washes, they were postfixed in 2% OsO4. in phosphate buffer at pH 7.4, 4°C for 2 hr, dehydrated through a graded series of ethanols, and embedded in Durcupan. Thin sections were observed and photographed without contrast-enhancement with heavy metals. Cytochemical reaction product marked the site of HRP (i.e., antigen) which, in turn, was present only where it was bound with anti-HRP antibody.

The fine structure of the guinea pig visceral yolk sac placenta

1970 ◽  
Vol 127 (4) ◽  
pp. 397-413 ◽  
Author(s):  
Barry F. King ◽  
Allen C. Enders
Keyword(s):  
Fine Structure ◽  
Guinea Pig ◽  
Yolk Sac ◽  
Visceral Yolk Sac ◽  
Yolk Sac Placenta

Uptake and metabolism of transferrin and albumin by rat yolk sac placenta

1984 ◽  
Vol 247 (5) ◽  
pp. C409-C414 ◽  
Author(s):  
H. J. McArdle ◽  
P. K. Priscott
Keyword(s):  
Molecular Weight ◽  
Weight Fraction ◽  
Yolk Sac ◽  
Rapid Phase ◽  
Visceral Yolk Sac ◽  
Transferrin Uptake ◽  
Hydrolysis Of ◽  
Molecular Weight Fractions ◽  
Uptake And Metabolism ◽  
Yolk Sac Placenta

The uptake of radiolabeled albumin and transferrin by the rat yolk sac and their subsequent transport to the embryo were studied. Transferrin uptake increases with incubation time whether the results are expressed in terms of the total amount accumulated or per milligram embryo or yolk sac protein, whereas albumin levels increase only in absolute terms. The fate of transferrin and albumin was examined by partitioning 125I into low- and high-molecular-weight fractions. Nearly all the embryonic radioiodine originally derived from transferrin is in the low-molecular-weight fraction, compared with only 60% albumin. These results have been extended by examining the uptake and hydrolysis of transferrin and albumin by the isolated yolk sac. Transferrin is taken up more rapidly than albumin. The release of hydrolyzed transferrin to the incubation medium occurred 40 min after the initiation of incubation, compared with 20 min for albumin. Transferrin uptake by the yolk sac at different transferrin concentrations showed an initial rapid phase followed by a slower linear phase, whereas albumin uptake increased linearly with concentration. There was no competition between the two proteins for uptake. Transferrin was released from the yolk sacs at approximately twice the rate of albumin. Results demonstrate at least two uptake mechanisms in the rat visceral yolk sac, one for transferrin, which probably involves receptor-mediated endocytosis, and one for albumin, by which transferrin can also be transported, which probably involves pinocytotic mechanisms.

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