Visualizing the spatiotemporal pattern of yolk sac membrane vascular network by enhanced local fractal analysis

2021 ◽  
Author(s):  
Peilun Li ◽  
Qing Pan ◽  
Sheng Jiang ◽  
Wolfgang M. Kuebler ◽  
Axel R. Pries ◽  
...  
Keyword(s):  
Fractal Analysis ◽  
Yolk Sac ◽  
Vascular Network ◽  
Spatiotemporal Pattern

Fractal Analysis of Vascular Network Pattern in Human Diseases

2005 ◽  
pp. 187-192 ◽  
Author(s):  
G. Bianciardi ◽  
C. De Felice ◽  
R. Cattaneo ◽  
S. Parrini ◽  
A. Monaco ◽  
...  
Keyword(s):  
Fractal Analysis ◽  
Vascular Network ◽  
Human Diseases ◽  
Network Pattern

scholarly journals Initiation of hematopoiesis and vasculogenesis in murine yolk sac explants

Blood ◽  
1995 ◽  
Vol 86 (1) ◽  
pp. 156-163 ◽  
Author(s):  
J Palis ◽  
KE McGrath ◽  
PD Kingsley
Keyword(s):  
Endothelial Cells ◽  
Network Formation ◽  
Globin Gene ◽  
Primitive Streak ◽  
Yolk Sac ◽  
Vascular Network ◽  
Globin Mrna ◽  
Capillary Networks ◽  
Stage Of Development ◽  
Extraembryonic Mesoderm

The blood islands of the visceral yolk sac (VYS) are the initial sites of hematopoiesis in mammals. We have developed a yolk sac explant culture system to study the process of blood cell and endothelial cell development from extraembryonic mesoderm cells. No benzidine-positive cells or beta H1-globin mRNA expression was detected at the primitive streak or neural plate stage of development (E7.5). However, when isolated E7.5 dissected tissues were cultured for 36 to 72 hours in serum-free medium, hundreds of hemoglobin-producing cells and embryonic globin gene expression were identified in both intact yolk sac and VYS mesoderm explants. Explanted E7.5 extraembryonic mesoderm tissues thus recapitulate in vivo primitive erythropoiesis and do not require the presence of a vascular network or the VYS endoderm. Yolk sac blood islands also contain endothelial cells that arise by vasculogenesis and express flk-1. We detected flk-1 mRNA as early as the primitive streak stage of mouse embryogenesis. Culture of embryo proper and intact VYS explants, which contain both mesoderm and endoderm cells, produced capillary networks and expressed flk-1. In contrast, vascular networks were not seen when VYS mesoderm was cultured alone, although flk-1 expression was similar to that of intact VYS explants. The addition of vascular endothelial growth factor to VYS mesoderm explants did not induce vascular network formation. These results suggest that the VYS endoderm or its extracellular matrix is necessary for the coalescence of developing endothelial cells into capillary networks.

Vascularization in the murine allantois occurs by vasculogenesis without accompanying erythropoiesis

Development ◽  
1998 ◽  
Vol 125 (22) ◽  
pp. 4507-4520 ◽  
Author(s):  
K.M. Downs ◽  
S. Gifford ◽  
M. Blahnik ◽  
R.L. Gardner
Keyword(s):  
Endothelial Cells ◽  
Blood Vessels ◽  
Cell Lineage ◽  
Immunohistochemical Analysis ◽  
Distal Region ◽  
Yolk Sac ◽  
Neural Plate ◽  
Vascular Network ◽  
Erythroid Cells ◽  
Erythroid Precursor

The aim of this study was to determine whether the blood vessels of the murine allantois are formed by vasculogenesis or angiogenesis. Morphological analysis revealed that differentiation of allantoic mesoderm into an outer layer of mesothelium and an inner vascular network begins in the distal region of the allantois, which is most remote from other tissues, as early as the late neural plate stage (approximately 7.75 days postcoitum). Nascent blood vessels were not found in the base of the allantois until 4-somite pairs had formed in the fetus (approximately 8.25 days postcoitum), and vascular continuity with the yolk sac and fetus was not present until the 6-somite-pair stage (approximately 8.5 days postcoitum). Immunohistochemical analysis demonstrated that flk-1, a molecular marker of early endothelial cells, is expressed in significantly more distal than basal core cells in the early allantois and never in mesothelium. Furthermore, synchronous grafting of donor yolk sac containing blood islands into blood islands of headfold-stage host conceptuses provided no evidence that the yolk sac contributes endothelial cells to the allantois. Finally, when removed from conceptuses and cultured in isolation, neural plate and headfold-stage allantoises formed a conspicuous vascular network that was positive for Flk-1. Hence, the vasculature of the allantois is formed intrinsically by vasculogenesis rather than extrinsically via angiogenesis from the adjacent yolk sac or fetus. Whether allantoic vasculogenesis is associated with erythropoiesis was also investigated. Benzidine-staining in situ revealed that primitive erythroid cells were not identified in the allantois until 6-somite pairs when continuity between its vasculature and that of the yolk sac was first evident. Nevertheless, a small number of allantoises removed from conceptuses at a considerably earlier stage were found to contain erythroid precursor cells following culture in isolation. To determine whether such erythroid cells could be of allantoic origin, host allantoises were made chimeric with lacZ-expressing donor allantoises that were additionally labeled with [3H]methyl thymidine. Following culture and autoradiography, many lacZ-expressing benzidine-stained cells were observed in donor allantoises, but none contained silver grains above background. Moreover, no cells of donor allantoic origin were found in the fetus or yolk sac. Hence, vasculogenesis seems to be independent of erythropoiesis in the allantois and to involve a distal-to-proximal gradient in differentiation of allantoic mesoderm into the endothelial cell lineage. Furthermore, this gradient is established earlier than reported previously, being present at the neural plate stage.

Dynamic Study of the Extraembryonic Vascular Network of the Chick Embryo by Fractal Analysis

1998 ◽  
Vol 195 (4) ◽  
pp. 525-532 ◽  
Author(s):  
Pierre G. Vico ◽  
Soula Kyriacos ◽  
Olivier Heymans ◽  
Stéphane Louryan ◽  
Louis Cartilier
Keyword(s):  
Chick Embryo ◽  
Fractal Analysis ◽  
Vascular Network ◽  
Dynamic Study

scholarly journals Histomorohological Studies on Ovary of Guppy (Poecilia Reticulata) And Development of Follicular Placenta

2021 ◽  
pp. 275-278
Author(s):  
Jagtap Nanda ◽  
Mote L. T.
Keyword(s):  
Connective Tissue ◽  
Poecilia Reticulata ◽  
Placental Tissue ◽  
Yolk Sac ◽  
Vascular Network ◽  
Mosquito Vectors ◽  
Water Reservoirs ◽  
Larvivorous Fish

The larvivorous fish Poecilia reticulata was propagated prolifically in the garden for control of mosquito vectors and later redistributed in a number of water reservoirs, in different villages nearby Dapoli. The gravid live bearing females were quickly dissected for their ovaries and embryos. The developed embryo with yellow rounded yolk sac, the remnants of the follicular placental tissue and thick vascular network of connective tissue was also observed.

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.

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