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Biomedical subjects

P M O'Brien

Publications and source records attributed to P M O'Brien.

At least 73 records · Page 4Linked to original sources
PubMed1988

Secretion of atrial natriuretic peptide and digoxin-like immunoreactive substance during pregnancy.

We investigated the secretion of atrial natriuretic peptide (ANP) and digoxin-like immunoreactive substance (DLIS) during pregnancy, labor, and the puerperium, as measured in maternal and umbilical cord plasma. There were no significant changes in maternal concentrations of ANP during all three periods, and the concentrations were similar to those found in nonpregnant controls and in umbilical cord plasma. Maternal concentrations of DLIS increased significantly in the second half of pregnancy, peaked during labor, then decreased abruptly within 24 h of expulsion of the infant and placenta to values approaching the nonpregnant range. DLIS concentrations in umbilical cord plasma, however, were significantly higher than in maternal plasma during labor. The abrupt fall in DLIS in maternal plasma and the absence of a significant difference in DLIS concentrations between arterial and venous cord plasma suggest that, during pregnancy, the fetus, not the placenta, is the source of DLIS in maternal plasma.

Atrial Natriuretic Factor↗
PubMed1987

Endocrine and metabolic effects of simple hysterectomy.

A survey of 60 women who had undergone simple hysterectomy with preservation of ovaries revealed a high prevalence of menopausal flushes. Only 5 (8%) had menopausal concentrations of gonadotropins and estradiol. This is similar to the prevalence of natural menopause in population of comparable age. Of the remaining 55 women, 28 (47% of the total) had normal gonadotrophins and estradiol concentrations although they complained of hot flushes; these levels were not significantly different from those in 27 women who did not flush. The "flushers" did, however, have significantly diminished bone mineral index and higher serum uric acid concentrations than the "non-flushers". Flushes disappeared in those women who took estrogen replacement therapy. These data show that although full-blown menopause does not increase in frequency following simple hysterectomy, a subtle diminution in estrogenisation is frequent. This hypo-estrogenisation is sufficient to cause: (a) hot flushes; (b) demineralisation of the skeleton and (c) an elevation in serum uric acid concentrations. There may be a case for estrogen therapy in all women who develop hot flushes following simple hysterectomy.

Adult↗
PubMed1987

The effect of prostaglandin E1 upon the pressor and hormonal response to exogenous angiotensin II in human pregnancy.

The effect of prostaglandin E1 (PGE1) on the pressor and hormonal response to angiotensin (ANG) II has been studied in 22 women in second trimester pregnancy. Three-point dose-response curves were initially determined for all women. Eleven then received an infusion of PGE1 while the remainder received an infusion of normal saline as controls. The dose-response curves to ANG II were re-studied after a period of stabilization. Although assignation to treatment group was random, differences were found in age and basal blood pressure between the control group and those given PGE1. The pressor data from the PGE1 group were thus split by age for analysis. The administration of ANG II alone was associated with significant (P less than 0.001 at all doses) pressor effects without accompanying bradycardia. Plasma renin concentration (PRC) was suppressed (P less than 0.001). Plasma aldosterone concentration rose (P less than 0.001), the magnitude of the rise being directly associated with the plasma ANG II concentrations achieved (P less than 0.05). The infusion of PGE1 had no significant effect on basal blood pressure, but evoked a sustained tachycardia in both age groups (P less than 0.001). Basal hormone concentrations were unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Effect of spironolactone on premenstrual syndrome symptoms.

The premenstrual syndrome (PMS) has long been considered one in which fluid retention plays an important role. Detailed studies, however, have failed to reveal good evidence for this assumption, and investigations of weight change and of sodium and water balance have yielded contradictory results. Even so, a number of the etiologic theories and treatment regimens are based on this premise. Many of the endocrine theories depend on the endocrine effect on water balance to explain the mechanism, and the treatment often proposed involves salt and water restriction and the liberal use of diuretics. There is no justification for this advice except for a few well-conducted studies that showed the benefits of diuretic therapy. The evidence from these studies suggests that diuretics, especially spironolactone, have a particular role in the management of the PMS symptoms of bloatedness and abdominal distension despite the fact that the underlying water retention theory remains in doubt. An improvement in the various psychologic symptoms of PMS has also been reported.

Adult↗
PubMed1985

The effect of dietary supplementation with linoleic and gammalinolenic acids on the pressor response to angiotensin II--a possible role in pregnancy-induced hypertension?

Dietary supplementation with 3 g/day linoleic acid, 32 mg/day gammalinolenic acid and co-factors for prostaglandin synthesis was given to 10 pregnant and 10 non-pregnant subjects for a week. Their pressor response to the infusion of three doses of angiotensin II (AII) (pregnant: 4, 8, 16 ng kg-1 min-1: non-pregnant: 1, 2, 4 ng kg-1 min-1) was then compared with that of 40 pregnant and 24 non-pregnant controls who had not been given such supplementation. Dietary supplementation was not associated with changes in basal systolic or diastolic blood pressure or heart rate during the week of treatment in pregnant or non-pregnant subjects. Basal systolic blood pressure, diastolic blood pressure and heart rate values did not differ between the treated and untreated subjects in each group. The diastolic pressor response to AII was significantly less after treatment at all doses; the effect was more marked in the pregnant subjects. The systolic response to AII, normally less than the diastolic, was somewhat blunted in the treated pregnant patients at the two higher infusion doses. No significant effect was found in the non-pregnant group. Evidence from other studies suggests that increasing plasma linoleic acid concentrations leads to increased plasma concentrations of epoprostenol (prostacyclin, PGI2) while increased availability of gammalinolenic acid is associated with a rise in prostaglandin E1 and E2 production. Pregnancy-induced hypertension is associated with a diminished tissue production of both epoprostenol and E series prostaglandins, and with an enhanced pressor response to AII.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

The premenstrual syndrome. A review.

The premenstrual syndrome (PMS) has gained much attention in the past few years. Despite the many studies that have attempted to determine the underlying biochemical changes in the syndrome and the larger number of studies attempting to evaluate treatment, we are really no wiser about PMS now than when the syndrome was described originally. The literature has been plagued by uncontrolled therapeutic trials, poorly conducted biochemical and endocrinologic studies and enthusiastic but unsubstantiated anecdotes. This review cannot hope to provide the answers since the background information is not yet established. However, providing an overview of current and past theories of the etiology and treatment regimens should enable the clinician and researcher to place new ideas and publications in perspective and to avoid many of the pitfalls of previous studies.

Adult↗
PubMed1985

A double-blind comparison of the new ibuprofen-codeine phosphate combination, zomepirac, and placebo in the relief of postepisiotomy pain.

In a double-blind, single-dose study, the analgesic effect of a combined ibuprofen-codeine phosphate preparation was compared with those of zomepirac and placebo in 127 patients with moderate or severe postepisiotomy pain. Both the combination and zomepirac were significantly more effective than placebo for up to six hours, but the onset of action of the combination was more rapid than that of zomepirac. The study was notable for the virtual absence of side effects.

Adult↗
PubMed1985

A double-blind comparison of a new ibuprofen-codeine phosphate combination, codeine phosphate, and placebo in the relief of postepisiotomy pain.

In a double-blind single-dose study, the analgesic effect of a new ibuprofen-codeine phosphate combination was compared with those of codeine phosphate alone and placebo for the relief of moderate and severe postepisiotomy pain. In the 113 patients studied, combination therapy was superior to codeine phosphate alone and to placebo, the difference between the combination and codeine phosphate alone reaching statistical significance (P less than 0.05) after two hours. The few side effects reported were not of a serious nature.

Clinical Trials as Topic↗
PubMed1984

Premenstrual syndrome: weight, abdominal swelling, and perceived body image.

One hundred forty-eight menstrual cycles were studied in 52 women, and in each cycle various parameters were measured to determine an objective means of assessing the syndrome. Daily mood assessment, body weight, plasma 17 beta-estradiol levels, and plasma progesterone levels were measured. The abdominal dimensions were measured in the lateral and anteroposterior diameters at the level of the umbilicus and 10 cm below; at the same time the same dimensions were measured as perceived by the patient. Mood score showed a marked increase during the premenstrual phase of each cycle. The symptom of bloatedness was marked during the premenstrual phase of the cycle. Despite these highly elevated scores for bloatedness there was no increase in body weight or the measured body dimensions in any plane. However, the patient's perception of body size did increase, and the discrepancy between the perceived body size and the actual body size (perception error) was significant.

Body Image↗
PubMed1984

The effect of prostaglandin E2 upon the biochemical response to infused angiotensin II in human pregnancy.

The effects of angiotensin II infusion without and with simultaneous infusion of prostaglandin E2 were studied in 25 women in second trimester pregnancy. Twenty received one infusion of angiotensin II alone, followed by its infusion simultaneously with prostaglandin E2; five received two identical infusions of angiotensin II alone as controls. Angiotensin II infusion alone was associated with suppression of plasma renin concentration to levels inversely proportional to the evoked change in diastolic blood pressure. Plasma renin substrate concentration was unchanged, but plasma aldosterone concentration rose markedly. This rise was inversely proportional to the threshold for pressor effect of angiotensin II. Prostaglandin E2 administration alone was associated with increased plasma renin concentrations. The pressor effect of angiotensin II was blunted when given together with prostaglandin E2 and plasma concentrations of angiotensin II reached were lower. Plasma renin concentration was again suppressed during the joint infusion regimen; the degree of suppression was inversely proportional to the change in diastolic pressure. Plasma aldosterone concentration rose, but did not differ in the control and experimental groups. Thus although the renin-angiotensin system is stimulated in normal pregnancy, the normal control mechanisms are still functional, and the capacity for further increases in activity exists.

Adolescent↗
PubMed1984

Seven years experience of home management in pregnancy in women with insulin-dependent diabetes.

Fifty-eight of a consecutive series of 75 pregnancies in women with insulin-dependent diabetes went into the third trimester. Diabetes was managed by home blood glucose monitoring and women were not routinely admitted at any stage before delivery. The mean number of in-patient days before delivery was 15 for the whole series but has been reduced to 9 during the past four years. Each woman performed an average of 171 blood glucose measurements during her pregnancy. Mean blood glucose (including post-prandial levels) fell significantly from 7.9 mmol/l in the first trimester to 7.3 in the second and 6.4 in the third. Mean percentage of haemoglobin A1 was within the normal range in the second and third trimesters. The cesarean section rate was high at 66% but there were no perinatal deaths. Three infants had congenital abnormalities. We conclude that home blood glucose monitoring is a safe and effective way of managing pregnant diabetic women as out-patients. The cost of meters and sticks is repaid many times over in the saving of hospital costs. In addition, home blood glucose monitoring is popular with the patients and many choose to continue it after delivery.

Blood Glucose↗
PubMed1983

Effects on the renin-angiotensin system of the administration of prostaglandin E1 and E2 in second trimester human pregnancy.

We have measured evoked changes in plasma renin concentration (PRC), plasma renin substrate (PRS) amd plasma aldosterone concentration (ALD) during the infusion of angiotensin II (AII) with and without the simultaneous administration of prostaglandin E2, 5 micrograms min-1 i.v. (PGE2) or prostaglandin E1, 15 ng kg-1 min-1 (PGE1). Experiments have been carried out using PGE2 in 20 patients, and in 5 patients to date with PGE1. AII alone (16 ng kg-1 min-1 i.v.) significantly reduced PRC in both groups of patients without altering PRS, while ALD concentrations more than doubled. The infusion of PGE2 stimulated basal PRC; PGE1 at the dose used did not alter PRC. Neither prostaglandin altered basal RS or ALD concentrations. When AII was infused simultaneously, PRC was again suppressed, in the presence of PGE2. However, only minimal feedback suppression occurred when PGE1 was being used. Furthermore, AII was still associated with a more than two-fold rise in ALD concentration when given together with PGE2, but the rise was considerably smaller and not significant in the presence of PGE1. PGE2 is a known stimulus to renin secretion, apparently acting directly at the juxtaglomerular apparatus. These preliminary results suggest that while a similar mechanism exists in second trimester human pregnancy, PGE1 may have a different effect. The apparent blockade of the normal feedback suppression of PRC in the presence of increased PGE1 concentrations by raised concentrations of AII is especially interesting.

Adult↗
PubMed1983

The effect of essential fatty acid and specific vitamin supplements on vascular sensitivity in the mid-trimester of human pregnancy.

Vascular sensitivity to angiotensin II was determined in the mid-trimester of pregnancy in women after taking a diet with supplemented essential fatty acids and vitamins. The essential fatty acids linoleic and dihommogammalinolenic acid were administered as evening primrose oil capsules (Efamol) for one week prior to the study. Vascular sensitivity was then determined in response to 4, 8 and 16 ng kg-1 min-1 angiotensin II. Vitamin supplements (Efavit) were given with the Efamol capsules. Seven women have been studied, and their vascular sensitivity compared with controls on normal diet. The vascular sensitivity was significantly reduced in all the patients on essential fatty acid supplements, and all values fell below the mean of the control group.

8,11,14-Eicosatrienoic Acid↗