Action of hydrocortisone on DNA synthesis in epithelial cells of the biliary tract

1974 ◽  
Vol 78 (6) ◽  
pp. 1417-1419
Author(s):  
P. A. Dyban
Keyword(s):  
Epithelial Cells ◽  
Dna Synthesis ◽  
Biliary Tract

Nuclear Morphology and the Ultra-Structural Localization of Deoxyribonucleic Acid Synthesis during Interphase

1969 ◽  
Vol 4 (3) ◽  
pp. 569-582
Author(s):  
GILLIAN R. MILNER
Keyword(s):  
Epithelial Cells ◽  
Dna Synthesis ◽  
Deoxyribonucleic Acid ◽  
Ultrastructural Localization ◽  
Cell Types ◽  
Acid Synthesis ◽  
Lung Fibroblasts ◽  
Nuclear Morphology ◽  
Structural Localization ◽  
Electron Microscope Autoradiography

The ultrastructural localization of deoxyribonucleic acid (DNA) synthesis was studied by electron-microscope autoradiography in human transforming lymphocytes, embryonic lung fibroblasts, epithelial cells and normoblasts. Euchromatin was found to be active in DNA synthesis in all cell types studied, whereas heterochromatin was inactive. However, DNA synthesis was also prominent in the regions where heterochromatin was thought to be decondensing to form euchromatin. Analysis of sequential changes in nuclear morphology of the transforming lymphocyte suggested that there is decondensation of heterochromatin during the S-phase until none is left. In nuclei with no heterochromatin a prominent localization of DNA synthesis was at the nuclear membrane. This sequence of complete decondensation of heterochromatin also seemed likely for fibroblasts and epithelial cells. Normoblasts however showed no stage where the nucleus was wholly euchromatic and it is suggested that in this cell decondensation of heterochromatin for replication is localized and transient.

scholarly journals Repeated allergen inhalations induce DNA synthesis in airway smooth muscle and epithelial cells in vivo

1998 ◽  
Vol 274 (3) ◽  
pp. L417-L424 ◽  
Author(s):  
Reynold A. Panettieri ◽  
Richard K. Murray ◽  
Andrew J. Eszterhas ◽  
Gulsevil Bilgen ◽  
James G. Martin
Keyword(s):  
Smooth Muscle ◽  
Epithelial Cells ◽  
Basement Membrane ◽  
Dna Synthesis ◽  
Airway Smooth Muscle ◽  
Allergen Challenge ◽  
Brown Norway ◽  
Small Airways ◽  
Airway Epithelial

Airway smooth muscle (ASM) mass appears to be increased in the bronchi of patients with chronic severe asthma. Although the precise mechanisms that induce these changes are unknown, increases in ASM mass are caused, in part, by ASM cell proliferation. After allergen challenge in rats, it has been possible to demonstrate an increase in ASM mass by morphometric techniques. To examine whether hyperplasia is involved in ASM cell growth in vivo, we investigated whether repeated allergen challenges in sensitized Brown Norway rats stimulated DNA synthesis in airway epithelial and ASM cells. Animals that were actively sensitized to ovalbumin (OA) received either three aerosolized OA or saline challenges at 5-day intervals. DNA synthesis was measured by indirect immunohistochemical techniques with an anti-bromodeoxyuridine (BrdU) antibody. OA inhalations increased ASM mass as determined by morphometry and also induced DNA synthesis in both airway epithelial and ASM cells in the airways of sensitized animals compared with saline-challenged control animals. ASM mass was increased in large- and medium-sized airways but not in small airways. However, the number of BrdU-positive ASM cells normalized to basement membrane length was also greater in the large- and medium-sized airways compared with that in the small airways. When the number of BrdU-positive epithelial cells was normalized to basement membrane length, there was no difference among airway sizes and the number of BrdU-positive epithelial cells. These data suggest that DNA synthesis is induced in both airway epithelial and ASM cells after inhalational antigen challenge.

Stimulation of DNA synthesis in cultures of ovine mammary epithelial cells by insulin and insulin-like growth factors

1989 ◽  
Vol 123 (2) ◽  
pp. 319-326 ◽  
Author(s):  
S. J. Winder ◽  
A. Turvey ◽  
I. A. Forsyth
Keyword(s):  
Epithelial Cells ◽  
Dna Synthesis ◽  
Time Course ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Mammary Tissue ◽  
Type I ◽  
Type I Igf Receptor ◽  
Pregnant Sheep ◽  
Igf I

ABSTRACT Ovine mammary epithelial cell clumps (30–90 μm) were plated onto attached gels of rat tail collagen in serum-free medium. Synthesis of DNA by these cultures could be stimulated by insulin-like growth factor-I (IGF-I) with a median effective dose of 5 μg/l, irrespective of stage of pregnancy. The time-course of response, however, was significantly slower in cells prepared from mammary tissue of non-pregnant and early pregnant sheep compared with sheep later in pregnancy. IGF-II had approximately 10% of the potency of IGF-I in stimulating DNA synthesis. Insulin acted over a wide concentration range and produced a maximum rate of stimulation not significantly different from that produced by IGF-I. These results are consistent with actions through the type-I IGF receptor although insulin may also act through its own receptor, possibly stimulating local IGF-I production. It is concluded that IGF-I is an important mitogen for ovine mammary epithelial cells. Journal of Endocrinology (1989) 123, 319–326

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