Production of prostaglandins E and Falpha by corpora lutea, corpora albicantes and stroma from the human ovary.

This study has shown that corpora lutea, stromal tissue and corpora albicantes from human ovaries contain prostaglandin E (PGE) and PGFalpha, and that the two former tissues can synthesize these prostaglandins during incubation. Enhanced syntheses, especially of PGE, occurred on adding arachidonic acid to the incubation medium, and the presence of prostaglandin synthetase activity was conclusively demonstrated. In corpora lutea obtained during the early and mid-luteal phase, the mean concentrations of PGE and PGFalpha were 34.3 and 9l9 ng/g respectively (mean ratio PGE:PGFalpha = 3.7); similar values were found in three corpora lutea from women at 10-12 weeks of pregnancy. All these corpora lutea contained appreciable amounts of progesterone and oestradiol-17beta. Prostaglandin levels were generally lower in corpora lutea obtained during the late luteal phase, although the PGE:PGFalpha ratio had increased to a mean value of 8.4. In corpora albicantes, the concentrations of both PGE and PGFalpha were significantly higher than the levels found in corpora lutea (P less than 0.01), whilst the mean ratio of PGE:PGFalpha had fallen significantly to 1.8 (P less than 0.01). Prostaglandin levels in stromal tissue varied considerably between individuals. The mean values were significantly lower than those of the corpora albicantes (P less than 0.01) but not significantly different to corpora lutea at any stage. These findings are discussed in relation to the possible role of prostaglandins in ovarian steroidogenesis and corpus luteum regression in man.

Improvement in decision-making for thrombolysis following introduction of angioplasty referral guidelines.

OBJECTIVE: To determine whether the introduction of acute angioplasty referral guidelines would lead to an improvement in decision-making times with respect to thrombolysis for patients with acute myocardial infarction. METHODS: Retrospective and prospective collection of 'time from diagnostic electrocardiogram to treatment' for all patients who received thrombolytic treatment for acute myocardial infarction in the emergency department. RESULTS: Median time from 'diagnostic electrocardiogram to thrombolysis' fell from 38 to 26 min (P < 0.0001) following introduction of acute angioplasty referral guidelines. This was primarily due to an improvement in median decision-making times for patients with anterior infarcts from 65 to 27 min (P = 0.0009). CONCLUSION: Significant improvements were seen in thrombolysis decision-making times for patients with acute myocardial infarction following the introduction of acute angioplasty referral guidelines.

The kinetics of extraamniotically injected prostaglandins to induce midtrimester abortion.

In an attempt to improve the extraamniotic administration of prostaglandins in effecting abortion, the movement of injected prostaglandins in a high or low viscosity medium has been observed by radiological studies and radioimmunoassy of PGE and PGFalpha in amniotic fluid and maternal plasma in association with intrauterine tocographic responses. Results obtained suggest that the immediate response by the uterus is a reflection of the speed of absorption of prostaglandins from the chorio-decidual space and that this influences the outcome in inducing abortion within 24 hours. By giving the prostaglandins in a viscous medium a slower release of prostaglandins was produced in most cases, which probably accounts for the greater efficacy obtained using single injections of prostaglandins in this vehicle compared with normal saline.

PIP: In an attempt to improve the extraamniotic administration of prostaglandins (PGs) in effecting abortion, the movement of injected PGs in a high or low viscosity medium has been observed by radiological studies and radioimmunoassay of PGE and PGFalpha in amniotic fluid and maternal plasma in association with intrauterine tocographic responses. Results obtained suggest that the immediate response by the uterus is a reflection of the speed of absorption of PGs from the choriodecidual space and that this influences the outcome in inducing abortion within 24 hours. By administering the PGs in a viscous medium, a slower release of PGs resulted in most cases, which probably accounts for the greater efficacy obtained using single injections of PGs this way as compared with normal saline.

Prostaglandins in the circulation of the fetal lamb.

Prostaglandin E and PGF have been measured in the plasma of chronically catheterized fetal lambs throughout the last 20-35 days (0.73 onwards) of gestation. The mean concentration of PGE was higher than that of PGF. There was a significant increase in the concentration of PGE but little change in the concentration of PGF in samples of fetal plasma taken within 24 h of parturition. In contrast, at this time in maternal utero-ovarian venous plasma, there was a large increase in PGF, but relatively little change in PGE. There was a significant decrease in the concentration of PGE and PGF in the plasma of lambs within 12 h after birth compared to the levels found in the same animals as fetuses a few hours previously. The physiological importance of these changes is discussed.