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Biomedical subjects

A B Anderson

Publications and source records attributed to A B Anderson.

At least 91 records · Page 5Linked to original sources
PubMed1977

Measurement of menstrual blood loss in patients complaining of menorrhagia.

A study has been made of menstrual blood loss measured in 50 women with unexplained heavy loss (more than 80 ml). Twelve of these women had an average menstrual loss greater than 200 ml, five women in excess of 450 ml. There was no relation between the duration of menstruation and the total menstrual blood loss. Compared to women with normal menstrual loss there was no difference either in the proportion of total menstrual loss passed on each day of menstruation in women bleeding heavily (92 per cent of the total menses being lost in the first three days) or in the coefficient of variation for menstrual blood loss from one period to the next. There was a reduction in menstrual blood loss in the first period following uterine curettage but no effect thereafter.

Adolescent↗
PubMed1977

Placental transfer and metabolism of betamethasone in human pregnancy.

The concentration of betamethasone has been measured in maternal peripheral plasma, umbilical cord artery and vein, and amniotic fluid following maternal administration of betamethasone phosphate and betamethasone acetate on 3 consecutive days. Betamethasone was measured by radioimmunoassay following column chromatography. The findings show that betamethasone is transferred across the human placenta, circulates in the fetus and appears in amniotic fluid. During the 3 days after the start of treatment, levels of the betamethasone were similar in maternal and umbilical cord blood and in amniotic fluid. Thereafter, although levels in the mother were measurable for up to 7 days after the initial injection, the drug was detected in the cord plasma of only one baby. In vitro incubation studies of human placental tissue with 3H betamethasone identified 11-keto betamethasone as the major metabolite of betamethasone.

Amniotic Fluid↗
PubMed1976

Contribution of preterm delivery to perinatal mortality.

A detailed retrospective analysis was made of the records of 486 preterm infants, who accounted for 5-1% of all births during 1973 and 1974. Whereas preterm delivery did not contribute to perinatal mortality in terms of stillbirth, it outweighed all other causes in terms of early neonatal deaths. Preterm birth was responsible for 85% of the early neonatal deaths not due to lethal congenital deformities. Early neonatal mortality rates were closely linked both to gestational age and birth weight and to the reason for preterm birth. Early neonatal mortality was high (97 per 1000) when preterm labour was spontaneous, whether or not associated with material or fetal disease or with multiple pregnancy, but low (27 per 1000) when preterm delivery was elective. Preventing spontaneous preterm labour would considerably reduce neonatal mortality in our community.

England↗
PubMed1976

Reduction of menstrual blood-loss by prostaglandin-synthetase inhibitors.

Six patients with menorrhagia due to dysfunctional uterine bleeding and one patient with an intrauterine contraceptive device were treated with prostaglandin-synthetase inhibitors in an attempt to reduce their excessive menstrual blood-loss. Mefenamic acid (six patients) or flufenamic acid (one patient) taken during menstruation for 2-3 cycles reduced menstrual loss in each patient. These preliminary observations suggest a new treatment for a common gynaecological problem and could imply that prostaglandins are involved in the aetiology of excessive menstrual blood-loss in such patients.

Adult↗
PubMed1976

Factors associated with spontaneous pre-term birth.

Factors associated with spontaneous pre-term birth in 283 singleton pregnancies were compared with those present in a total population of 16 994 women at risk studied in the First British Perinatal Mortality Survey. It was shown that the risk of spontaneous pre-term birth was related to low maternal age, low maternal weight, maternal smoking, low social class, illegitimacy, threatened abortion, and a previous history of antepartum haemorrhage, perinatal loss, or low birth weight livebirths.

Birth Weight↗
PubMed1976

A comparison of the effect of extradural and parenteral analgesia on maternal plasma cortisol concentrations during labour and the puerperium.

Maternal plasma levels of cortisol were measured serially by radioimmunoassay in two groups of 12 patients during induced labour and in the puerperium. One group was given continuous extradural analgesia throughout labour, the other group received pethidine and promazine in response to pain. Pre-induction cortisol levels were significantly higher in patients who were to have extradural analgesia but the percentage increase in plasma cortisol during labour was considerably less than in patients with parenteral analgesia; in second stage labour, mean cortisol levels were the same in the two groups. This study suggests that patients who had chosen to have extradural analgesia may have been more anxious before labour than the other patients but continuous, extradural analgesia suppressed to some extent the percentage increase in mean cortisol levels found during labour in patients given parenteral analgesia. In the puerperium, there was no difference in mean cortisol levels in the two groups.

Anesthesia, Epidural↗
PubMed1976

Bilateral adrenalectomy of lambs in utero: effects on maternal hormone levels at induced parturition.

Progesterone, 17 alpha, 20 alpha-dihydroxypregn-4-en-3-one, androstenedione, total unconjugated oestrogen and oestrone sulphate have been measured by radioimmunoassays in maternal utero-ovarian venous, maternal peripheral venous and/or foetal posterior vena caval plasma from six sheep bearing bilaterally adrenalectomized lambs, in which premature parturition was induced by administration of glucocorticoid. Three of the ewes were overiectomized, and in one of these three animals the foetal testes were also excised, at the time of foetal adrenalectomy. Adrenalectomy was judged to be complete on the basis of plasma cortisol levels in the neonatal lambs, and by examination of the site of ablation at necropsy. In all cases foetal administration of glucocorticoid led to the onset of labour, and lambing, and in all animals the hormonal changes preceding parturition were indistinguishable (either qualitatively or quantitatively) from the changes observed in animals carrying intact lambs. Since therapy with glucocorticoid alone successfully compensates for ablation of the foetal adrenal cortex, it is suggested that glucocorticoid is the only adrenal product required to cause parturition, and that foetal adrenal secretion of androgens may be unnecessary.

17-alpha-Hydroxypregnenolone↗
PubMed1975

Assessment of placental function in normal and pathological pregnancies by estimation of plasma oestradiol levels after injection of dehydroepiandrosterone sulphate.

A test of placental function was assessed by measurement of plasma oestradiol levels in 32 patients after intravenous injection of 50 mg dehydroepiandrosterone sulphate (DHAS). Every pregnant patient showed a rise in plasma oestradiol after DHAS; two puerperal patients showed no rise. It was not possible to distinguish the variable response in normal pregnancy from that in patients with severe hypertension and proteinuria or with retarded intrauterine fetal growth. The test was of no value in one hypertensive patient as a predictor of fetal death eight days later or, in another, to confirm fetal death of two days duration. Our results do not suggest that this test is a useful addition to currently available tests of placental endocrine function.

Birth Weight↗
PubMed1975

Mechanism of action of glucocorticoids in induction of ovine parturition: effect on placental steroid metabolism.

Maternal plasma progesterone levels in sheep may fall dramatically druing the last few days of gestation and following the administration of glucocorticoids to the foetus. To investigate the mechanism of the fall, metabolism of [3H] progesterone in vitro by ovin placental tissue was studied in five ewes before and after intra-foetal administration of dexamethasone in a dosage sufficient to induce parturition, and in one ewe after the spontaneous onset of labour at 143 days of gestation. Manual separation of maternal and foetal placental tissues showed that, in 11 out of 12 cases, the foetal and not the maternal placenta produced progesterone from pregnenolone in vitro. Total activities of cholesterol side-chain cleavage enzyme and 3beta-hydroxysteroid dehydrogenase in the foetal placenta were not influenced by intra-foetal dexamethasone. Befre administration of dexamethasone, homogenates of foetal placenta converted [3H] progesterone to 20alpha-hydroxy [3H]pregn-4-en-3-one in the presence of NADPH. Within 12 h of administration of dexamethasone, and after the natural onset of labour at 143 days, large amounts of 17alpha, 20alpha-dihydroxyI1pregn-4-en-3-one were formed form [3H]progesterone. Intra-foetal dexamethasone treatment also induced the formation of 17alpha, 20alpha-dihydroxy[3H]pregn-4-en-3-one by miced foetal placental tissue incubated with [3H]pregnenolone. This change in steroid metabolism did not occur in foetal placental tissue from a sham-operated animal receiving no dexamethasone. Assay of progesterone in foetal placentae showed that the increased fromation of 17alpha,20alpha-dihydroxypregn-4-en-3-one was unlikely to be caused by a change in the specific activity of added 3H-labelled precursor, although the production of 17alpha, 20alpha-dihydroxypregn-4-en-3-one in vitro increased at a time when both foetal placental and utero-ovarian venous levels of progesterone were decreasing in response to dexamethasone treatment. These observations indicate that intra-foetal dexamethasone treatment induces a placental 17alpha-hydroxylase enzyme, which is also present in foetal placental tissue after the spontaneous onset of labour at term.

17-alpha-Hydroxypregnenolone↗
PubMed1974

Endocrine changes in premature labour.

Plasma oestradiol and progesterone levels in peripheral blood have been studied before and during premature labour of unknown aetiology. Hormones were measured by radio-immunoassay using specific antisera. Levels in patients who delivered prematurely were compared with levels measured serially in 33 primigravidae during normal pregnancy and labour.In 19 out of 25 patients admitted in progressive premature labour the plasma oestradiol level was two standard deviations or more above the mean for the control patients of similar gestational age. The mean (+/- S.E. of mean) plasma oestradiol in premature labour was 19.1 +/- 1.1 ng/ml, similar to levels found in labour at term (18.5 +/- 1.4 ng/ml). In contrast, in over 50% of cases levels of plasma progesterone during premature labour lay below the mean for gestation though within the normal range. In six patients studied serially oestradiol levels rose dramatically, high values being detected one to 10 days before the onset of premature labour. Serial progesterone levels gave no consistent trend though one patient showed steadily decreasing values.These studies suggest that the onset of premature labour is preceded by a marked increase in peripheral plasma oestradiol levels, which may be of value not only in the prediction of premature labour but also in its prevention by suppression of the premature oestradiol surge.

Birth Weight↗