<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Griniatsos, John</style></author><author><style face="normal" font="default" size="100%">Michail, Othon P</style></author><author><style face="normal" font="default" size="100%">Theocharis, Stamatios</style></author><author><style face="normal" font="default" size="100%">Arvelakis, Antonios</style></author><author><style face="normal" font="default" size="100%">Papaconstantinou, Ioannis</style></author><author><style face="normal" font="default" size="100%">Felekouras, Evangelos</style></author><author><style face="normal" font="default" size="100%">Pikoulis, Emmanouel</style></author><author><style face="normal" font="default" size="100%">Karavokyros, Ioannis</style></author><author><style face="normal" font="default" size="100%">Bakoyiannis, Chris</style></author><author><style face="normal" font="default" size="100%">Marinos, George</style></author><author><style face="normal" font="default" size="100%">Bramis, John</style></author><author><style face="normal" font="default" size="100%">Michail, Panayiotis O</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Circadian variation in expression of G1 phase cyclins D1 and E and cyclin-dependent kinase inhibitors p16 and p21 in human bowel mucosa.</style></title><secondary-title><style face="normal" font="default" size="100%">World J Gastroenterol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">World J. Gastroenterol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Aged</style></keyword><keyword><style  face="normal" font="default" size="100%">circadian rhythm</style></keyword><keyword><style  face="normal" font="default" size="100%">Colon</style></keyword><keyword><style  face="normal" font="default" size="100%">Cyclin D1</style></keyword><keyword><style  face="normal" font="default" size="100%">Cyclin E</style></keyword><keyword><style  face="normal" font="default" size="100%">Cyclin-Dependent Kinase Inhibitor p16</style></keyword><keyword><style  face="normal" font="default" size="100%">Cyclin-Dependent Kinase Inhibitor p21</style></keyword><keyword><style  face="normal" font="default" size="100%">Female</style></keyword><keyword><style  face="normal" font="default" size="100%">G1 Phase</style></keyword><keyword><style  face="normal" font="default" size="100%">Humans</style></keyword><keyword><style  face="normal" font="default" size="100%">Immunohistochemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Intestinal Mucosa</style></keyword><keyword><style  face="normal" font="default" size="100%">Male</style></keyword><keyword><style  face="normal" font="default" size="100%">Middle Aged</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2006 Apr 07</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">12</style></volume><pages><style face="normal" font="default" size="100%">2109-14</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">AIM: To evaluate whether the cellular proliferation rate in the large bowel epithelial cells is characterized by circadian rhythm.

METHODS: Between January 2003 and December 2004, twenty patients who were diagnosed as suffering from primary, resectable, non-metastatic adenocarcinoma of the lower rectum, infiltrating the sphincter mechanism, underwent abdominoperineal resection, total mesorectal excision and permanent left iliac colostomy. In formalin-fixed and paraffin-embedded biopsy specimens obtained from the colostomy mucosa every six hours (00:00, 06:00, 12:00, 18:00 and 24:00), we studied the expression of G(1) phase cyclins (D(1) and E) as well as the expression of the G(1) phase cyclin-dependent kinase (CDK) inhibitors p16 and p21 as indicators of cell cycle progression in colonic epithelial cells using immunohistochemical methods.

RESULTS: The expression of both cyclins showed a similar circadian fashion obtaining their lowest and highest values at 00:00 and 18:00, respectively (P&lt;0.001). A circadian rhythm in the expression of CDK inhibitor proteins p16 and p21 was also observed, with the lowest levels obtained at 12:00 and 18:00 (P&lt;0.001), respectively. When the complexes cyclins D(1) -p21 and E-p21 were examined, the expression of the cyclins was adversely correlated to the p21 expression throughout the day. When the complexes the cyclins D(1) -p16 and E-p16 were examined, high levels of p16 expression were correlated to low levels of cyclin expression at 00:00, 06:00 and 24:00. Meanwhile, the highest expression levels of both cyclins were correlated to high levels of p16 expression at 18:00.

CONCLUSION: Colonic epithelial cells seem to enter the G(1) phase of the cell cycle during afternoon (between 12:00 and 18:00) with the highest rates obtained at 18:00. From a clinical point of view, the present results suggest that G(1) -phase specific anticancer therapies in afternoon might maximize their anti-tumor effect while minimizing toxicity.</style></abstract><issue><style face="normal" font="default" size="100%">13</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/16610066?dopt=Abstract</style></custom1></record></records></xml>