Biomaterial Database

Control of cell division in the cornea of rats II. Age-dependent effects of dexamethasone upon circadian mitotic activity. 1975

P G Cruze, and S S Cardoso

Data are presented here which verify that immature rats exhibit no circadian fluctuation of mitoses in the corneal epithelium prior to the third week of life. These data indicate that dexamethasone administration induces age-dependent alterations in the circadian mitotic pattern of the corneal epithelium. Nine day old animals still revealed no rhythmic component in circadian mitotic activity after dexamethasone treatment. Eleven-, 12- and 13-day old animals treated with dexamethasone exhibited circadian cycles which looked qualitatively like the circadian rhythm of the 15-day old animal. Fifteen-day old animals responded with a synchrony of mitotic activity at 0700 hr and a generalized decrease in mitotic activity. The possible dependence of these responses upon existing circadian mitotic activity and maturation of the central nervous system and/or the glucocorticoid target tissue is discussed.

UI	MeSH Term	Description	Entries
D008938	Mitosis	A type of CELL NUCLEUS division by means of which the two daughter nuclei normally receive identical complements of the number of CHROMOSOMES of the somatic cells of the species.	M Phase, Mitotic,Mitotic M Phase,M Phases, Mitotic,Mitoses,Mitotic M Phases,Phase, Mitotic M,Phases, Mitotic M
D002455	Cell Division	The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.	M Phase,Cell Division Phase,Cell Divisions,Division Phase, Cell,Division, Cell,Divisions, Cell,M Phases,Phase, Cell Division,Phase, M,Phases, M
D002940	Circadian Rhythm	The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs or environmental and physiological stimuli.	Diurnal Rhythm,Nyctohemeral Rhythm,Twenty-Four Hour Rhythm,Nycthemeral Rhythm,Circadian Rhythms,Diurnal Rhythms,Nycthemeral Rhythms,Nyctohemeral Rhythms,Rhythm, Circadian,Rhythm, Diurnal,Rhythm, Nycthemeral,Rhythm, Nyctohemeral,Rhythm, Twenty-Four Hour,Rhythms, Circadian,Rhythms, Diurnal,Rhythms, Nycthemeral,Rhythms, Nyctohemeral,Rhythms, Twenty-Four Hour,Twenty Four Hour Rhythm,Twenty-Four Hour Rhythms
D003315	Cornea	The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)	Corneas
D003907	Dexamethasone	An anti-inflammatory 9-fluoro-glucocorticoid.	Hexadecadrol,Decaject,Decaject-L.A.,Decameth,Decaspray,Dexasone,Dexpak,Hexadrol,Maxidex,Methylfluorprednisolone,Millicorten,Oradexon,Decaject L.A.
D000367	Age Factors	Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.	Age Reporting,Age Factor,Factor, Age,Factors, Age
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000831	Animals, Newborn	Refers to animals in the period of time just after birth.	Animals, Neonatal,Animal, Neonatal,Animal, Newborn,Neonatal Animal,Neonatal Animals,Newborn Animal,Newborn Animals
D049673	History, 20th Century	Time period from 1901 through 2000 of the common era.	20th Century History,20th Cent. History (Medicine),20th Cent. History of Medicine,20th Cent. Medicine,Historical Events, 20th Century,History of Medicine, 20th Cent.,History, Twentieth Century,Medical History, 20th Cent.,Medicine, 20th Cent.,20th Cent. Histories (Medicine),20th Century Histories,Cent. Histories, 20th (Medicine),Cent. History, 20th (Medicine),Century Histories, 20th,Century Histories, Twentieth,Century History, 20th,Century History, Twentieth,Histories, 20th Cent. (Medicine),Histories, 20th Century,Histories, Twentieth Century,History, 20th Cent. (Medicine),Twentieth Century Histories,Twentieth Century History
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus