The functional withdrawal of progesterone is mediated by the enhanced expression ratio of the 2 progesterone receptor (PR) isoforms, PRA and PRB, and causes the pregnant human myometrium to switch from a quiet state to a state of excitation-contraction and subsequent laboring. However, the precise mechanisms responsible for alterations in PRA and PRB expression during human parturition have yet to be resolved. In the present study, we report that PRA expression was increased in myometrium samples during labor (P < .001), concomitant with reduced expression of histone deacetylase 1 (HDAC1; P < .01). These results were further confirmed in the laboratory using cultured primary myometrial cells to investigate the effects of HDAC1 knockdown or overexpression. Finally, we verified that HDAC1 downregulated PRA expression by binding to the promoter region of PRA as confirmed by chromatin immunoprecipitation assays (P < .01) and real-time polymerase chain reaction (P < .001). Therefore, the present study not only demonstrates the epigenetic mechanisms underlying human labor but also provides a potential clinical strategy with which to intervene and prevent labor disorders.

We report on the design and construction of a series of coupled pendula to demonstrate various aspects of wave motion, such as normal modes, standing waves, a dispersion relation, and evanescence waves. The experiment can help undergraduate students obtain a better understanding of the properties of wave motion.

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Liver stiffness measured using two-dimensional shear wave elastography could predict symptomatic post-hepatectomy liver failure using the best cut-off value of 9.5 kPa.Child-Turcotte-Pugh grade was a stronger indicator of symptomatic post-hepatectomy liver failure in minor hepatectomy, while liver stiffness was more effective in selecting candidates for major hepatectomy.Liver stiffness could further stratify the risk of symptomatic post-hepatectomy liver failure in Child-Turcotte-Pugh grade A patients, regardless of the extent of hepatectomy (