A P4 is a set of four vertices of a graph that induces a chordless path; the P4-structure of a graph is the set of all P4’s. Vašek Chvátal asked if there is a polynomial time algorithm to determine whether an arbitrary four-uniform hypergraph is the P4-structure of some graph. The answer is yes; we present such an algorithm.

In cattle, elevated concentrations of circulating progesterone (P4) in the immediate postconception period are associated with advanced conceptus development, while low P4 is implicated as a causative factor in low pregnancy rates observed in dairy cows. This study aimed to: 1) describe the transcriptional changes that occur in the bovine endometrium during the estrous cycle, 2) determine how e...

Calcium-related proteins include the calcium transporters 1 and 2 (CaT1 and CaT2), plasma membrane Ca2+-ATPase 1b (PMCA1b), and calbindin-D9k and -D28k. The expression of CaT1 and PMCA1b and their potential roles in the uterine tissue remain to be clarified. Thus, in the present study, the expression patterns of CaT1 and PMCA1b were examined to predict their roles in rat uterus during the estro...

Progesterone (P4) was demonstrated to inhibit migration in vascular smooth muscle cells (VSMCs), but to enhance migration in T47D breast cancer cells. To investigate the mechanism responsible for this switch in P4 action, we examined the signaling pathway responsible for the P4-induced migration enhancement in breast cancer cell lines, T47D and MCF-7. Here, we demonstrated that P4 activated the...

To investigate the correlation between ovarian structures and progesterone (P4) concentrations in Egyptian buffaloes (n=80), blood and milk samples were in association with gynecological examination. There was a positive correlation (r=0.38, P<0.005) between serum and milk P4 levels and the presence of CL resulted in an elevation of P4 (P<0.0001) as compared with smooth inactive ovary. The high...

Transcription from the late promoter, PA3, of Bacillus subtilis phage phi 29 is activated by the viral regulatory protein p4. A kinetic analysis of the activation process has revealed that the role of protein p4 is to stabilize the binding of RNA polymerase to the promoter as a closed complex without significantly affecting further steps of the initiation process. Electrophoretic band-shift ass...

The aim of the study was to determine, in an experiment performed on conscious gilts, whether an increased amount of progesterone (P4) supplied to the porcine corpus luteum (CL), maintained within a physiological systemic concentration would influence its own secretion. On day 9 of the estrous cycle the jugular veins as well as both ovarian arteries and both ovarian veins were cannulated. In th...

E. Strambini, a) F. S. Bergeret, 3, 4, b) and F. Giazotto c) NEST Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy Centro de F́ısica de Materiales (CFM-MPC), Centro Mixto CSIC-UPV/EHU, Manuel de Lardizabal 4, E-20018 San Sebastián, Spain Donostia International Physics Center (DIPC), Manuel de Lardizabal 5, E-20018 San Sebastián, Spain Institut für Physik, Carl von Ossie...

Objective To investigate whether mid-luteal serum progesterone (P4) exhibits significant fluctuations during a 12-h daytime period in women undergoing in vitro fertilization (IVF) and to explore whether the extent of these fluctuations could impact the interpretation of luteal progesterone levels in a clinical setting. Design Explorative pilot study. Setting Public hospital-based fertility ...