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E D Gallery

Publications and source records attributed to E D Gallery.

At least 55 records · Page 3Linked to original sources
PubMed1986

Sodium excretion in human pregnancy: a role for arginine vasopressin.

Plasma arginine vasopressin concentration was measured before and after 1 week's dietary sodium loading (greater than 250 mmol/day) or deprivation (less than 50 mmol/day) in 50 second-trimester and 34 third-trimester primigravidas. A significant rise in plasma arginine vasopressin was observed only in second-trimester subjects following sodium loading (5.6 +/- 0.5 to 6.6 +/- 0.5 pg/ml; p less than 0.05). Plasma sodium concentration and blood pressure did not alter, and plasma volume increased slightly in this group (24.4 +/- 0.5 to 25.9 +/- 0.7 ml/cm height; p less than 0.01). Hence the observed increment in plasma arginine vasopressin concentration in this group could not be explained by alterations to the major factors regulating arginine vasopressin release. It is suggested that arginine vasopressin secretion increases to assist natriuresis following dietary sodium loading in the second trimester of human pregnancy.

Adult↗
PubMed1986

Potassium regulation and progesterone-aldosterone interrelationships in human pregnancy: a prospective study.

Little is known about the intrinsic renal and hormonal regulation of potassium excretion in pregnancy despite major alterations in many of the potassium regulatory factors. Forty primigravid women on an unrestricted diet were studied during the second and third trimesters and exhibited constant absolute and fractional potassium excretion despite a significant increase in plasma aldosterone concentration between these stages. The plasma progesterone level rose significantly between studies but closer analysis showed no correlation between individual changes in plasma aldosterone concentration and progesterone between trimesters. In the 14 subjects studied post partum, baseline absolute potassium excretion was not significantly altered but filtered potassium fell and fractional potassium excretion tended to rise. After dietary sodium manipulation at these stages, absolute potassium excretion, fractional potassium excretion, and progesterone were unaltered despite significant changes in plasma aldosterone concentration and sodium excretion. These results suggest that potassium excretion is held constant throughout pregnancy and that renal tubular potassium reabsorption adjusts appropriately to the increased filtered potassium load. Progesterone does not appear to be involved in the acute regulation of potassium or sodium excretion but may have effects on sodium and potassium excretion that are constant, proportional to its placental production, and unresponsive to endogenous changes in mineralocorticoid production.

Aldosterone↗
PubMed1986

The effect of cyclical hormonal changes on erythrocyte electrolyte transport mechanisms.

Electrolyte transport characteristics were examined in erythrocytes from 13 normal men and from two groups of women: taking combined oral contraceptive preparations (O/C, n = 10), and ovulatory women (non-O/C, n = 10) pre- and post-ovulation, at the same time intervals (days 7-10 and days 15-18) during a menstrual cycle. With rubidium (86Rb+) used as a potassium analogue, co-transport (ouabain-resistant, frusemide-sensitive 86Rb+ influx) values were found to be lowest in non-O/C women (28 +/- SE 2.5 nmol h-1 10(-9) cells) and highest in men (56 +/- 5.7, P less than 0.001), with results between the two in women taking O/C (42 +/- 4.2, P less than 0.05 vs men, P less than 0.01 vs non-O/C). Passive 86Rb leak (frusemide-and ouabain-resistant) was significantly lower in men (13 +/- 1.6 nmol h-1 10(-9) cells) than in both groups of women (non-O/C 29 +/- 1.8, P less than 0.001; O/C 25 +/- 1.2, P less than 0.001). There was no cyclical variation within either group of women. Maximum ouabain binding (number of NA+,K+-ATPase units) was the same in all groups. Na+,K+-ATPase activity, as determined by ouabain-sensitive 86Rb influx, was the same in men and non-O/C groups, but was significantly suppressed in O/C compared with both men (P less than 0.01) and non-O/C women (P less than 0.05). The differences found were not due to alterations in either progesterone or aldosterone, but could represent an androgenic effect in vivo of the 19-nortestosterone derivatives in combined oral contraceptive preparations.

Adult↗
PubMed1985

Antihypertensive treatment in pregnancy: analysis of different responses to oxprenolol and methyldopa.

One hundred and eighty three hypertensive pregnant women were randomly assigned to antihypertensive treatment with oxprenolol (96 women) or methyldopa (87 women). Control of hypertension was equivalent in both treatment groups, and in 64 (35%) cases hydralazine had to be added to the treatment to achieve the therapeutic goal (diastolic blood pressure below 85 mm Hg). Five perinatal deaths occurred, one in the oxprenolol group and four in the methyldopa group. Detailed analysis confirmed a previous report of greater fetal growth in the group treated with oxprenolol; this trend was present regardless of severity of hypertension and parity. With increasing duration of treatment the differences between the two groups diminished, and there was no difference after 10 weeks of treatment, a finding that may explain some of the reported discrepancies among therapeutic studies. As hypertension in pregnancy may pursue an accelerated course, necessitating urgent delivery, and there is no satisfactory method of predicting the duration of treatment in individual patients fetal benefit is most likely to be achieved by treatment with oxprenolol, provided that there is no maternal contraindication to treatment with beta blockers.

Adult↗
PubMed1985

Hypertension in pregnant women.

Although hypertension is the most common and significant risk factor in pregnancy, the risks can be minimized with careful supervision and therapy. The mere presence of hypertension, even of severe hypertension, is neither a contraindication to pregnancy nor an indication for the termination of pregnancy, provided that appropriate management principles are applied. For optimum management, the skills of the obstetrician, the physician and, later in pregnancy, of the neonatologist should all be employed to the full. The ability to monitor the fetus closely, and to offer intensive care to the premature newborn, is critical in making decisions about the timing and mode of delivery. These women, as all other women with high-risk pregnancies, should be receiving treatment in centres which can offer adequate care both to the mother and to the baby.

Adrenergic beta-Antagonists↗
PubMed1985

Are the renal functional changes of human pregnancy caused by prostacyclin?

To investigate the hypothesis of others that the many characteristic physiological alterations of pregnancy are due to prostacyclin, the effects of this vasodilator prostaglandin on renal function and related variables were measured. Intravenous infusion of prostacyclin (7 ng/kg/min) for 90 minutes in seven healthy male volunteers resulting in a significant fall in diastolic blood pressure and increase in heart rate. No significant change occurred in renal plasma flow or glomerular filtration rate in response to the prostacyclin, but there were significant falls in uric acid clearance (16 +/- 1.3----10 +/- 1.5 ml/min/ 1.73m2) and in free water clearance (4.0 +/- 1.1-----0.5 +/- 0.4 ml/min) both of which rose rapidly to pre-infusion levels upon cessation of prostacyclin infusion. Plasma renin and aldosterone levels rose sharply during prostacyclin infusion, falling to pre-infusion levels rapidly afterwards. Although the haemodynamic alterations were similar, the renal functional effects of prostacyclin infusion were quite different from (and often opposite in direction to) those of normal pregnancy. This acute study therefore does not add support to the hypothesis suggested by others that these alterations in pregnancy are due to prostacyclin, and that deficiency of prostacyclin will lead to the changes of pregnancy-associated hypertension.

Adult↗
PubMed1984

Fall in blood pressure in response to volume expansion in pregnancy-associated hypertension (pre-eclampsia): why does it occur?

The infusion of 500 ml of a volume expanding solution caused a significant fall in blood pressure for up to 72 h in 35 women with pregnancy-associated hypertension of varying grades of severity. The response to the infusion was not obviously related to the clinical severity of the underlying disorder, nor to the extent of plasma volume expansion produced. The plasma volume of oedematous women increased, while there was no significant change in non-oedematous women in response to the infusion. Changes in other measurements were similar in oedematous and non-oedematous women. There was no evidence for prostacyclin release into the circulation in response to the infusion as a mediator of the blood pressure response. Both 6-keto-prostaglandin F1 alpha levels and 13,14-dihydro-15-keto-prostaglandin F (PGFM) levels fell significantly, suggesting suppression of prostaglandin release by the infusion. The antihypertensive effect of volume expanders in pregnancy-associated hypertension is mediated by a factor other than simple volume expansion.

Adult↗
PubMed1984

Role of renin and aldosterone in establishment of electrolyte balance in very low birthweight neonates.

Urine sodium, potassium and chloride excretion, plasma renin activity (PRA) and urine aldosterone excretion (UAE) were measured in seven very low birthweight (VLBW) infants during the first 6 weeks after birth. Hyponatraemia was most common, and major changes in urine electrolyte excretion occurred, during the first 2 weeks. These changes in urine electrolyte excretion appeared to relate to improvement in distal tubular function. PRA did not correlate with urine excretion of either aldosterone or electrolytes. However, UAE correlated significantly with fractional sodium-potassium exchange in the distal tubule in a non-linear fashion (P less than 0.001) which suggested a threshold of aldosterone responsiveness between 70 and 100 nmol/24 h per 1.73 m2 UAE. We conclude that in VLBW infants the distal tubule can respond to aldosterone during the first 2-3 weeks, but that the threshold for responsiveness appears to be higher than it is in fullterm infants.

Aldosterone↗
PubMed1984

Chronic hypertension in pregnancy.

Chronic hypertension in pregnancy is associated with significant potential risks to both mother and baby. The risks can be reduced to, or even below those of the general population by appropriate and adequate therapy. This requires close supervision and maintenance of excellent blood pressure control and should involve in therapeutic decisions, not only the obstetrician, but also the physician and neonatologist. In our own experience this is best achieved by a specialised unit approach to the problem.

Antihypertensive Agents↗
PubMed1982

Pregnancy-associated hypertension: interrelationships of volume and blood pressure changes.

In normal human pregnancy there is considerable expansion of both plasma volume and total extracellular fluid volume, together with marked diminution of vascular reactivity in response to intravenous infusion of vasopressor agents. Pregnancy-associated hypertension (pre-eclampsia) is characterised by increased vascular reactivity, vasoconstriction and a fall in plasma volume associated with a shift of fluid from intravascular to interstitial fluid space. Direct expansion of plasma volume in patients with pregnancy-associated hypertension leads to partial correction of the abnormalities of volume homeostasis together with a significant fall in blood pressure. Certain forms of antihypertensive therapy also lead to reversal of volume contraction and improvement in cardiac function. This is associated with lowered vascular resistance and improved placental function, leading to improved pregnancy outcome. Although these observations do not elucidate the ultimate cause/causes of pregnancy-associated hypertension, they help to unravel the pathologic mechanisms by which the syndrome causes its effects and to suggest rational paths by which therapeutic endeavours may be expected to benefit mother and fetus.

Blood Pressure↗
PubMed1981

Effect of diazoxide on the antepartum cardiotocograph in severe pregnancy-associated hypertension.

Intravenous diazoxide was given to 8 patients with severe pregnancy-associated hypertension (diastolic pressure greater than or equal to 110) in the antepartum period. Maternal hypertension was rapidly controlled in all patients; the diastolic blood pressure fell to less than or equal to 100 in all patients and to less than or equal to 85 in 7. Diazoxide had no significant effect on the basal fetal heart rate (FHR) or on the latency period or amplitude of late decelerations in the 3 patients with abnormal (positive) stress cardiotocographs (SCTG) and abnormal (unreactive) non-stress cardiotocographs (NSCTG). In the 5 patients with reactive NSCTGs, diazoxide had no significant effect on the basal FHR or on the frequency of fetal movement-induced FHR accelerations. Thus, diazoxide did not adversely affect fetal well-being in these patients with severe pregnancy-associated hypertension as assessed by cardiotocography.

Blood Pressure↗
PubMed1981

Antihypertensive effect of plasma volume expansion in pregnancy-associated hypertension.

Plasma and total extracellular fluid volume expansion was confirmed in normal pregnant women in the third trimester of pregnancy. The plasma volume contraction of pregnancy-associated hypertension (pre-eclampsia) was found to be associated with an increase in the interstitial compartment of extracellular fluid volume. The infusion of a plasma volume expander produced significant amelioration of hypertension for 48 h associated with partial reversal of the disturbance of fluid distribution. This finding confirms the central place of volume contraction in maintenance of elevated blood pressure in pregnancy-associated hypertension.

Adult↗
PubMed1981

A prospective study of serum complement (C3 and C4) levels in normal human pregnancy: effect of the development of pregnancy-associated hypertension.

Serum levels of complement components (C3 and C4) were measured serially in 173 initially normotensive pregnant women and the results compared with those obtained in 32 nonpregnant women of similar ages. There was significant elevation of serum levels of both C3 and C4 during gestation. Pregnancy-associated hypertension developed in the third trimester in 26 pregnant women but they had the-same degree of elevation of serum C3 and C4 levels as did the 147 pregnant women who remained normotensive throughout their pregnancy. Measurements of serum C3 and C4 levels and therefore of no value in predicting the development of pregnancy-associated hypertension.

Adolescent↗
PubMed1980

Cardiac and haemodynamic measurements in hypertensive pregnancy.

1. Haemodynamic and left ventricular variables were determined by M-mode echocardiography in 21 normotensive and 36 hypertensive patients during the last trimester of pregnancy. 2. Blood pressure of hypertensive patients was lowered by bed rest only, or by oxprenolol or methyldopa, but remained elevated. 3. Cardiac output was raised in the last trimester of pregnancy in both normotensive and hypertensive patients. 4. Left ventricular mass was increased in normal pregnancy, but displayed an exaggerated increase in hypertensive patients. 5. Total peripheral resistance was inappropriately elevated in hypertensive pregnancy, except in the oxprenolol-treated group. 6. There ws no reduction in heart rate or cardiac output in the group treated with beta-adrenoreceptor blocking agents. These factors, in combination with normal peripheral resistance, may contribute to the improvement in foetal outcome described in maternal hypertension of pregnancy treated with oxprenolol.

Adult↗
PubMed1980

Hypertension in pregnancy.

Hypertension complicates 10-15% of pregnancies and is associated with an increased rate of fetal loss at all stages of gestation, intrauterine fetal growth retardation and prematurity, either because of spontaneous premature labour or of the occasional necessity for early delivery.

Blood Pressure↗