No abstract

Summary. Experiments are described that were designed to show the time and site of the contraceptive action of an intrauterine copper device in the rat. The IUD had no effect on fertilization. Progressively fewer embryos survived, the later the device was removed during the afternoon and evening of the 4th day of pregnancy. The presence of the IUD for the first few hours only of embryonic life completely suppressed implantation, causing death of the embryos. Exposure of the pseudopregnant uterus to copper for the same period was unable to affect the decidual response to traumatization. It was concluded that the contraceptive action of the copper is due to the fact that its presence results in an embryotoxic environment which causes the death of the embryos before any noticeable effect on the endometrium. As the embryos are not killed immediately they enter the uterine lumen, it is likely that death occurs at a time in the development of the embryo when it becomes sensitive to the toxins. Such a time could be the period of transition from the morula stage to the blastocyst.

Experiments are described that demonstrate the ability of dibutyryl cyclic AMP (dcAMP) to induced oestrogen-like changes in the uteri of ovariectomized mice treated with progesterone. A single intraluminal injection of 6-14 micrograms dcAMP in 0-02 ml phosphate-buffered saline promoted cell division in the uterine stroma and sensitized the endometrium so that a decidual reaction could be induced by a subsequent injection of arachis oil into the uterine lumen. Since dcAMP has already been shown to induce implantation of diapausing mouse blastocysts in the absence of oestrogen, it is suggested that cyclic AMP is involved in egg implantation in rodents.

Ambulance personnel and casualty staff in 62 London casualty departments were asked in a questionnaire survey for their recommendations for the management of cases of deliberate self-poisoning. From the 1350 questionnaires distributed, 1248 (92 %) were returned, of which 858 were completed by doctors and nurses. Among this group 88% believed that these patients should never be discharged without full psychiatric evaluation,

The technique for assessing the ability of a compound to initiate the decidual response is simple and conclusive. It involves introducing the compound in solution into the uterine lumen of an intact rat or mouse during the`sensitive period' of pseudopregnancy (Finn & Keen, 1963;Hetherington, 1968). This technique was used to compare the ability of arachis oil, phosphate-buffered saline (PBS; Dulbecco & Vogt, 1954) and dibutyryl adenosine 3',5'-monophosphate (dibutyryl cyclic AMP\p=m-\dcAMP) to initiate the decidual response after injection into the uterine lumen of the mouse at various times on the 4th day of pseudopregnancy.Pseudopregnancy was induced in A2G mice from a closed colony in the Department, by mating them with vasectomized males of the same strain, vaginal plugs being taken to indicate the 1st day of pseudopregnancy. Animals were allocated to fifteen groups, each comprising four to seven mice. On the 4th day at 09.30, 12.30 or 15.30 hours, a single intraluminal injection (by way of the uterotubal junction) of 0\m=.\02 ml arachis oil, PBS or a solution of dcAMP (Sigma) in PBS was given. Three concentrations of dcAMP were used: 1\m=.\25 mm, 2\ m=. \ 5 mM and 3\ m=. \ 75 mm. At autopsy on the 7th day, the horns were excised, divided at the cervix and weighed separately before being fixed in Bouin's solution for subsequent histological examination.