[论文解读] Robust convex relaxation for the planted clique and densest k-subgraph problems

Brendan Ames|arXiv (Cornell University)|May 21, 2013

Complexity and Algorithms in Graphs参考文献 48被引用 13

一句话总结

本研究调查了大鼠在假性妊娠和妊娠期间每日催乳素高峰的调节机制，发现尽管存在胎盘催乳素和蜕膜组织，妊娠期间的催乳素高峰仍会提前终止，而这些因素并不能完全解释提前终止的原因。结果表明，除胎盘催乳素或蜕膜化之外，可能存在尚未被识别的其他机制，抑制妊娠期间的催乳素高峰。

ABSTRACT

The pattern of plasma prolactin following uterine cervical stimulation consists of two surges each day, one nocturnal, occurring between 0100-0900 h (lights on 0600-1800 h), and one diurnal, occurring between 1500-2100 h. This pattern of prolactin continued throughout pseudopregnancy; the last surge was observed on the morning of day 11 (day 1 was taken as the first day of diestrus of pregnancy or pseudopregnancy). Prolactin levels remained low thereafter until the spontaneous proestrous surge on the afternoon of day 12, signalling the onset of a new estrous cycle. In contrast, the two daily prolactin surges did not continue throughout pregnancy, and in fact, were terminated sooner in pregnant animals than in pseudopregnant animals. The last diurnal surge was observed on day 8 while the last nocturnal surge was observed on day 10. The early termination of prolactin surges during pregnancy correlated with the increased secretion of rat placental lactogen. However, placental extracts obtained from day 11 of pregnancy and injected in large doses failed to inhibit prolactin surges in pseudopregnant animals. Prolactin surges also continued for a longer period of time in pseudopregnant rats bearing decidualized uteri than in pregnant animals. Thus, the two major components of pregnancy that differed from pseudopregnancy, that is, the presence of rat placental lactogen or decidual tissue, did not appear to account for the early termination of prolactin surges during pregnancy.

研究动机与目标

• 理解大鼠在假性妊娠和妊娠期间每日催乳素高峰的激素调节机制。
• 确定大鼠胎盘催乳素或蜕膜组织是否导致妊娠期间催乳素高峰的提前终止。
• 比较假性妊娠与妊娠动物催乳素高峰的持续时间与模式。
• 评估外源性胎盘提取物是否能抑制假性妊娠模型中的催乳素高峰。

提出的方法

• 在假性妊娠和妊娠期间，定期监测大鼠血浆催乳素水平。
• 识别出两个每日催乳素高峰：一个夜间高峰（0100–0900 h），一个日间高峰（1500–2100 h）。
• 从假性妊娠第1天开始追踪这些高峰的持续时间，直至第12天，包括动情间期高峰。
• 从妊娠第11天的大鼠中提取胎盘提取物，给予假性妊娠动物，以检测其抑制作用。
• 比较具有或不具有蜕膜化子宫的假性妊娠大鼠中高峰的持续时间。
• 将高峰终止时间与胎盘催乳素和蜕膜组织的存在情况进行相关分析。

实验结果

研究问题

• RQ1 大鼠的每日催乳素高峰是否在假性妊娠和妊娠的整个持续时间内均持续存在？
• RQ2 妊娠期间催乳素高峰的提前终止是否由大鼠胎盘催乳素介导？
• RQ3 与妊娠相比，蜕膜化子宫的存在是否会延长催乳素高峰的持续时间？
• RQ4 来自妊娠大鼠的外源性胎盘提取物是否能抑制假性妊娠大鼠中的催乳素高峰？
• RQ5 妊娠期间抑制催乳素高峰的机制是否能被胎盘催乳素或蜕膜组织完全解释？

主要发现

• 催乳素高峰持续至假性妊娠第11天，最后一次高峰出现在第11天的早晨。
• 在妊娠动物中，最后一次日间高峰出现在第8天，最后一次夜间高峰出现在第10天，表明其终止时间早于假性妊娠。
• 妊娠期间催乳素高峰的提前终止与大鼠胎盘催乳素分泌增加相关。
• 给予假性妊娠动物大剂量来自妊娠第11天大鼠的胎盘提取物，未能抑制其催乳素高峰。
• 具有蜕膜化子宫的假性妊娠大鼠中，催乳素高峰持续时间长于妊娠动物。
• 胎盘催乳素或蜕膜组织单独作用，均无法完全解释妊娠期间催乳素高峰的提前抑制。