Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 160 (1980), S. 275-284 
    ISSN: 1432-0568
    Keywords: Adenohypophyseal rudiment ; Follicular cells ; Ultrastructure ; Culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The epithelial rudiment of 4 day-old quail embryo adenohypophysis, cultivated in vitro under conditions allowing glandular differentiation, displays peripheral cells that progressively acquire follicular cell features. They elongate, develop numerous microvilli, junctional complexes, interlocking membranes and bundles of microfilaments. These follicular-like cells derive from peripheral epithelial cells that, in situ, become glandular. These results show that follicular cells can develop from undifferentiated cells. They undergo this pathway of development, in all likelihood, as a result of perturbations in their microenvironment.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 156 (1979), S. 255-267 
    ISSN: 1432-0568
    Keywords: Adenohypophyseal rudiment ; Self-differentiation ; Ultrastructure ; Quail
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Isolated epithelial rudiments of 3–4 days quail embryo adenohypophysis were cultivated in vitro. Differentiation of glandular cells occured when culture conditions allowed the formation of explants characterized by the presence of a fibroblastic sheet and of an epithelial roof surrounding a central cavity. Differentiation did not occur when culture conditions did not allow the fibroblastic sheet to be established or resulted in the absence of a cavity. The importance of the explant structure in differentiation is also indicated by the location of glandular cells. In vitro they differentiate near the cavity derived from Rathke's pouch lumen while in situ they first appear at the periphery of the rudiment, near the basement membrane. The results of this study show that the adenohypophyseal primordium can differentiate without any mesenchymal influence. The observed differentiation seems to be correlated with fibroblast-secreted material, and this hypo-thesis is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 153 (1978), S. 23-36 
    ISSN: 1432-0568
    Keywords: Electron microscopy ; Quail embryo ; Rathke's pouch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Adenohypophyseal region of quail embryo has been examined by electron microscopy from stage 12 to stage 21 of Zacchei (1961). The Seessel's pouch develops prior to the early stages of adenohypophysis formation, then regresses while Rathke's pouch proliferates and differentiates. From Rathke's pouch formation by stage 12 (48 h of incubation) until appearance of the first secretory granules by stage 21 (6 days of incubation), there are no major ultrastructural modifications in adenohypophyseal cells. Mitochondria, Golgi vesicles, polysomic ribosomes, pinocytotic vesicles, and mitotic figures become more numerous while nucleocytoplasmic ratio and the number of ribosomes and lipid droplets decreases. The major change is the appearance of secretory granules by day 6 of incubation. This phenomenon occurs at the same time as in chick embryo, despite an incubation period shorter for quail than for chick. Mitotic figures are mainly distributed near the pouch lumen, while secretory granules are first located in the peripheral cells of the cephalic part ofpars distalis primordium. The hypothetical role of mesenchyme and vascularization is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 108 (1991), S. 145-149 
    ISSN: 1573-4919
    Keywords: cholinesterases ; acetylcholinesterase ; butyrylcholinesterase ; epithelial cell ; human intestine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The epithelial cells of the human intestine exhibit a cholinesterase activity which is restricted to the apex of the villi. This activity displays a maximum in the colon and a minimum in the jejunum. Contrary to most of the studied vertebrates, the human cells present both acetylcholinesterase and butyrylcholinesterase activities, acetylcholinesterase being predominant in all the intestinal segments: duodenum, jejunum, ileum and colon. Like in the other vertebrates, only globular forms are identified by sucrose gradient centrifugation. However, the simultaneous presence, on the one hand of three globular forms (G1, G2 and G4) and, on the other hand of soluble as well as detergent-soluble molecular species seems to be a particular feature of the human cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1573-4919
    Keywords: cholinesterase ; butyrylcholinesterase ; mucosal cell ; enterocyte ; sex-related ; chicken intestine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The butyrylcholinesterase activity of chick enterocytes was studied from day 15 in ovo up to day 90 after hatching. The activities detected in both sexes at the level of jejuno-ileum change in a parallel manner, but the activity is always higher in the female than in the male during embryonic development. After hatching, the differences are less apparent although the study of the enzyme distribution along the intestine showed sex-related variations, mainly at the level of the anterior and middle parts of jejuno-ileum in the young adult. Analysis of butyrylcholinesterase by sucrose gradient centrifugation allowed to identify two globular soluble species (G1 and G4 forms). The G4/(G1 + G4) ratio decreases during the development but this variation in the female does not parallel that observed in the male. Besides, the molecular form distribution along the intestine, studied after hatching, differs according to the sex. Taken together our results lead to hypothesize that the ontogeny and the regulation of the chick enterocyte butyrylcholinesterase depend on hormones.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1573-4919
    Keywords: cholinesterase ; butyrylcholinesterase ; molecular forms ; mucosal cells ; chicken intestine ; development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The mucosal cells of the chicken intestine contain a cholinesterase activity essentially due to butyrylcholinesterase. The enzyme is present during embryonic and post-hatching development. The activity reaches a maximum value at day 19 in ovo and decreases prior to and after hatching up to day 4 ex ovo. Then the activity again rises reaching a second maximum at 2–3 weeks. Beyond this stage, the activity slowly decreases leveling off to the value determined in adult chicken. The enzyme exists as two globular forms (G1 and G4) soluble at low-ionic strengths. The G4 form is predominant in ovo up to day 19. From this stage and after hatching the G1 form is the main one. This change in the form proportion differentiates the mucosal cell butyrylcholinesterase from butyrylcholinesterase of other origins such as the chicken plasma enzyme which always shows a predominant G4 form.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 85 (1989), S. 49-56 
    ISSN: 1573-4919
    Keywords: cholinesterase ; butyrylcholinesterase ; molecular forms ; mucosal cells ; chicken intestine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The presence of a butyrylcholinesterase (BuChE, EC 3.1.1.8) in the musocal cells of the chicken intestine was demonstrated by histochemical and biochemical methods. The study of its distribution, along the intestine from duodenum to rectum, showed that the jejuno-ileum possesses the highest activity. Sucrose gradient centrifugation revealed, in all intestinal areas, two globular forms with sedimentation coefficients of 4.3 S (G1 form) and 10.8 S (G4 form). The presence of Triton X-100 in the preparations did not modify the sedimentation profiles of these two forms which can be considered as soluble BuChE. The ratio of G1/G4-forms progressively decreases along the intestine from duodenum to rectum indicating a predominance of the G4 form in the areas where the activity is low. Our results are discussed in relation to other studies of globular forms of chicken BuChE.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Epithelial rudiments of adenohypohysis were removed from chick and quail embryos between days 3 and 5 of development. Chick rudiments were grafted for 11-13 days onto the chorioallantoic membrane of decapitated chick embryo hosts. Quail rudiments were cultivated in vitro for 6 days. Both grafted and cultivated Rathke's pouches differentiated into adenohypophyseal tissue. The adenohypophyseal tissue cultured on chorio-allantoic membrane exhibited cells reacting with the following immune sera: anti-β-(1-24)ACTH, anti-α-(17-39)-ACTH, anti-α-endorphin, anti-β-endorphin and anti-β-LPH, which also gave a positive reaction when applied to adenohypophysis of corresponding age which had differentiated in situ. In situ, corticotrophs were located exclusively in the cephalic lobe of adenohypophysis. Therefore, the differentiation of corticotrophs in the whole graft, i.e., from both cephalic and caudal lobes of Rathke's pouch, showed that the cells of the caudal lobe, or at least some of them, were uncommitted when the rudiment was removed. In vitro, tissue derived from Rathke's pouch contained cells reacting with antibodies to β-(1-24)-ACTH, α-(17-39)-ACTH, and β-LPH, as did adenohypophysis from quail embryos of corresponding age (9-10 days), differentiated in situ. The differentiation of quail Rathke's pouch in vitro corroborates that differentiation can occur without influence from hypothalamus and, moreover, shows that at least some kinds of cells can differentiate without influence exerted by any other encephalic factors, and in the absence of mesenchyme. The question arises whether fibroblastic cells derived from Rathke's pouch cells act as feeder-cells and/or secrete some factors promoting differentiation.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...