Magnetic control of cell sheets promises new insights

2021 ◽  
Author(s):  
Cordelia Sealy
Keyword(s):  
Author(s):  
J. P. Revel

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.


Author(s):  
R. Stephens ◽  
G. Schidlovsky ◽  
S. Kuzmic ◽  
P. Gaudreau

The usual method of scraping or trypsinization to detach tissue culture cell sheets from their glass substrate for further pelletization and processing for electron microscopy introduces objectionable morphological alterations. It is also impossible under these conditions to study a particular area or individual cell which have been preselected by light microscopy in the living state.Several schemes which obviate centrifugation and allow the embedding of nondetached tissue culture cells have been proposed. However, they all preserve only a small part of the cell sheet and make use of inverted gelatin capsules which are in this case difficult to handle.We have evolved and used over a period of several years a technique which allows the embedding of a complete cell sheet growing at the inner surface of a tissue culture roller tube. Observation of the same cell by light microscopy in the living and embedded states followed by electron microscopy is performed conveniently.


2004 ◽  
Vol 171 (4S) ◽  
pp. 460-460
Author(s):  
Yoshiyuki Shiroyanagi ◽  
Masayuki Yamato ◽  
Yuichiro Yamazaki ◽  
Teruo Okano ◽  
Hiroshi Toma
Keyword(s):  

1960 ◽  
Vol XXXIV (I) ◽  
pp. 27-32 ◽  
Author(s):  
Stian Erichsen ◽  
Weiert Velle

ABSTRACT The metabolism of some oestrogenic hormones was studied in vitro by the use of cells grown on a medium free from blood. The methods used for the culture of cells from bovine testis, endometrium, amnion, and liver in confluent cell sheets on glass are described. The interconversion of oestrone and oestradiol-17β was demonstrated in the presence of cells from amnion, endometrium, and also from testicles of young calves and bulls. Only trace amounts of oestrone were found following incubations with oestradiol-17α in these tissues. Bovine liver cells grown in vitro showed a very poor capacity to bring about the interconversion mentioned above.


2018 ◽  
Vol 71 (4) ◽  
pp. 163-169
Author(s):  
Eiji Kobayashi ◽  
Shin Enosawa

Abstract: Introduction: Research has made progress in organ fabrication using an extracellular matrix, cell sheets, or organoids. Human liver tissue has been constructed using a 3-dimensional (3D) bioprinter and showed evidence that an in vitro generated liver bud was reformed in a rodent liver model. This study describes the stages of development of rat fetal organs and liver structure and reviews recent progress in liver organoid transplantation. Methods: The authors developed the procedures for creating a transected plane for use in experimental microsurgery in rats. A liver lobe was fixed vertically with gauze and it was ligated with 6-0 silk suture in the cut line; the parenchyma was cut, and major vessels were ligated to create the transected plane. The ligated tissue was carefully resected. Hemostasis was not required and hepatic components remained on the transected plane. The plane was covered by omentum. Results: Using this model, we transplanted fetal liver or a 3D bioprinted liver organoid. This microsurgical method enabled creation of an intact liver parenchyma plane. No bleeding was observed. The transplanted liver components successfully engrafted on the liver. Conclusion: This method may provide an essential environment for growing liver using portal and arterial blood flow.


2020 ◽  
Vol 110 ◽  
pp. 141-152
Author(s):  
Taro Inagaki ◽  
Tsunetaro Morino ◽  
Ryo Takagi ◽  
Masayuki Yamato ◽  
Izumi Koizuka ◽  
...  

Biomaterials ◽  
2009 ◽  
Vol 30 (29) ◽  
pp. 5427-5432 ◽  
Author(s):  
Imen Elloumi Hannachi ◽  
Kazuyoshi Itoga ◽  
Yoshikazu Kumashiro ◽  
Jun Kobayashi ◽  
Masayuki Yamato ◽  
...  

Genetics ◽  
2003 ◽  
Vol 165 (1) ◽  
pp. 159-169
Author(s):  
Benjamin Boettner ◽  
Phoebe Harjes ◽  
Satoshi Ishimaru ◽  
Michael Heke ◽  
Hong Qing Fan ◽  
...  

Abstract Rap1 belongs to the highly conserved Ras subfamily of small GTPases. In Drosophila, Rap1 plays a critical role in many different morphogenetic processes, but the molecular mechanisms executing its function are unknown. Here, we demonstrate that Canoe (Cno), the Drosophila homolog of mammalian junctional protein AF-6, acts as an effector of Rap1 in vivo. Cno binds to the activated form of Rap1 in a yeast two-hybrid assay, the two molecules colocalize to the adherens junction, and they display very similar phenotypes in embryonic dorsal closure (DC), a process that relies on the elongation and migration of epithelial cell sheets. Genetic interaction experiments show that Rap1 and Cno act in the same molecular pathway during DC and that the function of both molecules in DC depends on their ability to interact. We further show that Rap1 acts upstream of Cno, but that Rap1, unlike Cno, is not involved in the stimulation of JNK pathway activity, indicating that Cno has both a Rap1-dependent and a Rap1-independent function in the DC process.


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