Menstruation has been a puzzling problem, not only to the laity but also to the physician and to the biologist. The nature of menstruation and, if one may say so, its biological meaning, have been quite obscure until a few years ago, but recent biological analyses, based upon and continuing Heape's and Marshall's fundamental work, revealed facts and relations which really provide an explanation...

Nitric oxide production, catalyzed by nitric oxide synthase (NOS), should be strictly regulated to allow embryo implantation. Thus, our first aim was to study NOS activity during peri-implantation in the rat uterus. Day 6 inter-implantation sites showed lower NOS activity (0.19±0.01 pmoles L-citrulline mg prot(-1) h(-1)) compared to days 4 (0.34±0.03) and 5 (0.35±0.02) of pregnancy and to day 6...

It has been shown that both prostaglandin I2 (PGI2) and PGE2 are essential for mouse implantation, whereas only PGE2 is required for hamster implantation. To date, the expression and regulation of cyclooxygenase (COX) and prostaglandin E synthase (PGES), which are responsible for PGE2 production, have not been reported in the rat. The aim of this study was to examine the expression pattern and ...

may result from or be the cause of amenorrhoea, and in either case may lead to severe anxiety or more serious psychological illness. D-lusions of pregnancy, with or without signs of pseudopregnancy, are not uncommon, and are a further source of confusion. Diagnosis of pi egnancy may be impossible by physical examination alone for the first few weeks after conception, and speed may be important ...