scholarly journals Patterning of the Avian Intermediate Mesoderm by Lateral Plate and Axial Tissues

2003 ◽  
Vol 253 (1) ◽  
pp. 109-124 ◽  
Author(s):  
Richard G. James ◽  
Thomas M. Schultheiss
Development ◽  
1999 ◽  
Vol 126 (6) ◽  
pp. 1103-1108 ◽  
Author(s):  
T. Obara-Ishihara ◽  
J. Kuhlman ◽  
L. Niswander ◽  
D. Herzlinger

The nephric duct is the first epithelial tubule to differentiate from intermediate mesoderm that is essential for all further urogenital development. In this study we identify the domain of intermediate mesoderm that gives rise to the nephric duct and demonstrate that the surface ectoderm is required for its differentiation. Removal of the surface ectoderm resulted in decreased levels of Sim-1 and Pax-2 mRNA expression in mesenchymal nephric duct progenitors, and caused inhibition of nephric duct formation and subsequent kidney development. The surface ectoderm expresses BMP-4 and we show that it is required for the maintenance of high-level BMP-4 expression in lateral plate mesoderm. Addition of a BMP-4-coated bead to embryos lacking the surface ectoderm restored normal levels of Sim-1 and Pax-2 mRNA expression in nephric duct progenitors, nephric duct formation and the initiation of nephrogenesis. Thus, BMP-4 signaling can substitute for the surface ectoderm in supporting nephric duct morphogenesis. Collectively, these data suggest that inductive interactions between the surface ectoderm, lateral mesoderm and intermediate mesoderm are essential for nephric duct formation and the initiation of urogenital development.


Development ◽  
1970 ◽  
Vol 24 (2) ◽  
pp. 367-380
Author(s):  
Glenn C. Rosenquist

The origin of the presumptive nephrogenic cells in the epiblast of the chick embryo was traced by radioautographic analysis of the movements of tritiated thymidine-labelled grafts excised from medium-streak to 5-somite stage embryos and transplanted to epiblast, streak, and the endoderm-mesoderm layer of similarly staged recipient embryos. The nephrogenic cells originate near the area pellucida margin of the medium-streak-stage embryo, migrate toward the streak, and are invaginated about one-third to one-half the distance from the anterior to the posterior end of the streak, between the definitive-streak and I - to 4-somite stages. Their route into mesoderm is along a relatively narrow pathway between the cells migrating to the paraxial or presomite mesoderm on one side, and those destined for the proximal limbs of the lateral plate on the other. The cells which will form the anterior part of the intermediate mesoderm are the most medially placed cells in epiblast, reach the streak at an earlier stage of development, and are the first nephrogenic cells to migrate into mesoderm. After about the 17– to 19-somite stage, cells from this group which have formed the pronephric cord or duct begin to move posteriorly in relation to the rest of the intermediate mesoderm, toward the future cloaca. The last nephrogenic cells to leave epiblast and enter the streak and mesoderm are those destined for the posterior end of the intermediate mesoderm. This group of cells surrounds the posteriorly migrating pronephric (Wolffian) duct and differentiates into mesonephros.


Development ◽  
1990 ◽  
Vol 109 (4) ◽  
pp. 775-786 ◽  
Author(s):  
C. Kress ◽  
R. Vogels ◽  
W. De Graaff ◽  
C. Bonnerot ◽  
F. Meijlink ◽  
...  

The mouse Hox-2.3 gene contains an Antp-like homeobox sequence and is expressed in a spatially restricted anteroposterior domain during development. To study the molecular basis of this differential gene regulation, we set out to characterize the cis-regulatory elements mediating Hox-2.3 expression during embryogenesis. We show that a fragment extending 1316 base pairs (bp) upstream of the transcription start site, thus corresponding to the Hox-2.4/Hox-2.3 intergenic sequences is capable of mediating luciferase gene transcription in transfected cells in vitro and lacZ expression in transgenic mice. The beta-galactosidase-staining pattern in embryos was found to be strikingly similar to the Hox-2.3 in situ hybridization pattern in intermediate mesoderm derivatives: high levels of both Hox-2.3 transcripts and beta-galactosidase activity were found in the mesonephric duct-derived epithelium of the meso- and metanephric kidney and associated ducts, from the time these structures first appeared on throughout development. The transgene apparently lacks sequences needed for correct Hox-2.3 expression in somitic and lateral plate mesoderm and in neurectoderm. These results document the involvement of distinct regulatory elements in Hox gene expression in subsets of cells with distinct developmental fate, situated at similar positions along the anteroposterior axis of the embryo.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Daisuke Takahashi ◽  
Yoshihiro Noyama ◽  
Tsuyoshi Asano ◽  
Tomohiro Shimizu ◽  
Tohru Irie ◽  
...  

Abstract Background Internal fixation is recommended for treating Vancouver B1 periprosthetic femoral fractures. Although several fixation procedures have been developed with high fixation stability and union rates, long-term weight-bearing constructs are still lacking. Therefore, the aim of the present study was to evaluate the stability of a double-plate procedure using reversed contralateral locking compression-distal femoral plates for fixation of Vancouver B1 periprosthetic femoral fractures under full weight-bearing. Methods Single- and double-plate fixation procedures for locking compression-distal femoral plates were analysed under an axial load of 1,500 N by finite element analysis and biomechanical loading tests. A vertical loading test was performed to the prosthetic head, and the displacements and strains were calculated based on load-displacement and load-strain curves generated by the static compression tests. Results The finite element analysis revealed that double-plate fixation significantly reduced stress concentration at the lateral plate place on the fracture site. Under full weight-bearing, the maximum von Mises stress in the lateral plate was 268 MPa. On the other hand, the maximum stress in the single-plating method occurred at the defect level of the femur with a maximum stress value of 1,303 MPa. The principal strains of single- and double-plate fixation were 0.63 % and 0.058 %, respectively. Consistently, in the axial loading test, the strain values at a 1,500 N loading of the single- and double-plate fixation methods were 1,274.60 ± 11.53 and 317.33 ± 8.03 (× 10− 6), respectively. Conclusions The present study suggests that dual-plate fixation with reversed locking compression-distal femoral plates may be an excellent treatment procedure for patients with Vancouver B1 fractures, allowing for full weight-bearing in the early postoperative period.


2018 ◽  
Vol 10 (1) ◽  
pp. 87-100 ◽  
Author(s):  
Charles Yoon ◽  
Hannah Song ◽  
Ting Yin ◽  
Damaris Bausch-Fluck ◽  
Andreas P. Frei ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document