Search Results - (Author, Cooperation:D. J. Craven)

2013-09-17

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Carbon Dioxide/metabolism ; *Ecosystem ; Nitrogen Fixation/*physiology ; Panama ; Species Specificity ; Symbiosis/*physiology ; Trees/growth & development/*metabolism ; *Tropical Climate

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Plasma renin and angiotensin II levels were measured in nine patients immediately before and at half-hourly intervals in the four hours following therapeutic termination of pregnancy. There was a small fall in renin and angiotensin II levels over the first 1 to 2 hours, followed by a slight increase. The magnitude of these effects was much smaller than those previously seen following normal delivery. It is concluded that in early pregnancy maternal, rather than feto-placental, factors are controlling the renin-angiotensin system.

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Amniotic fluid lecithin has been measured during the antenatal period and at comparable periods of gestation at the onset of spontaneous labour. Lecithin values were higher in labour, the difference being statistically significant in two of the three groups studied. Lecithin values were also measured serially during induced labour in 14 normal women at term. A significant fall was observed throughout labour. Creatinine levels were measured in the amniotic fluid in five of these patients and showed no significant change.

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Summary. Myometrium, decidua, chorio-decidua and amnion were collected from women undergoing caesarean section and from pregnant women at hysterectomy and hysterotomy for comparison with myometrium, cervix and endometrium taken from non-pregnant women at hysterectomy. Homogenates of chorio-decidua and amnion contained the largest concentrations of active and inactive renin. Cultured explants of all tissues except amnion were found to produce both types of renin. The percentage of active renin produced before 20 days of culture was significantly greater in cultures of chorio-decidua than in those of myometrium (P 〈 0,0005) or decidua Vera (P〈 0.029, which suggests that renin synthesis in vivo is probably confined to the chorio-decidua.

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Plasma angiotensin-converting enzyme (ACE) has been measured prospectively throughout pregnancy, at delivery and in the puerperium in 18 normotensive primi-gravidae and their infants. Plasma ACE was consistently lower during pregnancy than in comparable, non-pregnant controls, but rose progressively from about 30 weeks to term. At vaginal delivery maternal and fetal ACE levels did not differ significantly. There was a steady increase in maternal ACE activity up to 6 weeks post partum, when the levels were not significantly different from non-pregnant controls. No correlation could be found between plasma ACE and plasma renin activity or concentration, or plasma AIL Plasma aldosterone increased in parallel with ACE during the last ten weeks of pregnancy.

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Serial measurements of plasma renin and plasma aldosterone were made throughout pregnancy in two women with adrenal insufficiency. The values were compared with levels obtained in eight normal primigravidae. Aldosterone levels were low or undetectable in adrenal insufficiency and plasma renin levels were grossly elevated in one patient with adrenal insufficiency but within the normal range in the other.

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Summary. Blood samples were obtained by fetoscopy from 30 fetuses in the middle trimester of pregnancy. The results indicate that high concentrations of renin and relatively low levels of renin substrate are present in the fetus early in pregnancy. These values are similar to those previously demonstrated in the full-term fetus.

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Plasma renin concentration, renin activity and angiotensin II (AII) have been studied in 35 primigravidae at or near term immediately prior to surgical induction of labour. A highly significant positive correlation was established between diastolic blood pressure at the time of sample collection and plasma AII. This relationship was observed over the range of diastolic pressure studied irrespective of the diagnosis made at the time of admission to hospital. In patients with hypertension, a significant negative relationship was established between plasma renin concentration and renin activity and AII. Furthermore, plasma AII levels were higher for a given plasma renin activity or plasma renin concentration in the hypertensive women than in the normotensive group. These findings suggest that the renin-angiotensin system is actively involved in hypertensive disease of pregnancy and that suppressed levels of renin concentration and activity may result from elevated angiotensin levels. It is suggested that the utero-placental complex may be the source of the elevated AII levels.

Electronic Resource