Biomedical subjects
E M Symonds
Publications and source records attributed to E M Symonds.
Customised antenatal growth charts.
Charts for fetal growth do not take physiological variables into account. We have therefore designed a computer-generated antenatal chart that can be easily "customised" for each individual pregnancy, taking the mother's characteristics and birthweights from previous pregnancies into consideration. The adjusted birthweight range expected at 40 weeks' gestation is combined with a standard, longitudinal ultrasound-derived curve for intrauterine weight gain. Review at the Queen's Medical Centre, Nottingham, UK, of 4179 pregnancies with ultrasound-confirmed dates showed that, in addition to gestation and sex, maternal weight at first antenatal-clinic visit, height, ethnic group, and parity were significant determinants of birthweight in our population. Correction factors were calculated for each of these variables and entered into a computer program to adjust the normal birthweight centile limits. With adjusted centiles we found that 28% of babies conventionally designated small for gestational age (less than 10th centile) and 22% of those designated large (greater than 90th centile) were in fact within normal limits for the pregnancy. Conversely, 24% and 26% of babies identified as small or large, respectively, with adjusted centiles were "missed" by conventional unadjusted centile assessment. Adjustment for physiological variables will make assessment of fetal growth more precise and reduce unnecessary investigations, interventions, and parental anxiety.
The resolution of chronic pelvic pain after normal laparoscopy findings.
Sixty patients with chronic pelvic pain were monitored after diagnostic laparoscopy had excluded obvious pelvic pathology. Six months after the procedure only two patients described their symptoms as unchanged or worse. Treatment should be limited to the minority of patients whose symptoms remain 6 months after laparoscopy.
Changes in human platelet angiotensin II binding sites associated with early pregnancy.
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Longitudinal study of platelet angiotensin II binding in human pregnancy.
1. Platelet angiotensin II binding, circulating angiotensin II levels, plasma renin substrate and plasma renin concentration were measured in a longitudinal study of 30 women during pregnancy and the puerperium. 2. There was a significant fall in platelet angiotensin II binding from 11 weeks gestation to 18 weeks gestation (P less than 0.01). There were no further significant changes in platelet angiotensin II binding until after delivery, a significant rise in platelet angiotensin II binding being found at 6 weeks post partum as compared with at 36 weeks gestation (P less than 0.01). There was no further significant change from 6 to 12 weeks post partum, and platelet angiotensin II binding at 6 and 12 weeks post partum in the pregnant cohort approximated to that in nonpregnant women. These changes parallel those known to occur in pressor responsiveness to angiotensin II in pregnancy. 3. Plasma angiotensin II concentration, plasma renin substrate and plasma renin concentration were all significantly higher during pregnancy than in the puerperium (P less than 0.001). There were no significant changes during pregnancy in plasma angiotensin II concentration or plasma renin concentration, although plasma renin substrate rose throughout. 4. Significant inverse correlations between platelet angiotensin II binding and plasma angiotensin II concentration (P less than 0.01), plasma renin substrate (P less than 0.01) and plasma renin concentration (P less than 0 greater than 001) were found during pregnancy. These data suggest that down-regulation of platelet angiotensin II binding by the components of the renin-angiotensin system pertains in pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)
Comparative study of platelet angiotensin II binding and the angiotensin II sensitivity test as predictors of pregnancy-induced hypertension.
1. Platelet angiotensin II binding was measured in 34 primigravid women (between 28 and 32 weeks gestation), in whom the pressor response to infused angiotensin II was also determined. 2. There was a significant correlation between the platelet angiotensin II binding and the slope of the curve relating the diastolic pressor response to infused angiotensin II (P less than 0.01), suggesting that co-linearity between the two techniques exists and supporting the use of platelet angiotensin II binding as a model of vascular smooth muscle pressor responsiveness. 3. Ten of the 34 women subsequently developed pregnancy-induced hypertension. Platelet angiotensin II binding in the patients who subsequently developed pregnancy-induced hypertension was sixfold higher than in the patients who remained normotensive (P less than 0.001). There were, however, no significant differences between the groups in any of the parameters derived from the angiotensin II infusion experiments. 4. The use of platelet angiotensin II binding alone in predicting the outcome of the pregnancies, as assessed using discriminant analysis, was more successful than when any of the infusion parameters were used, with 77% of patients being correctly classified.
A randomised placebo controlled trial of labetalol in the treatment of mild to moderate pregnancy induced hypertension.
OBJECTIVE: To determine the need for, and efficacy of, treatment with labetalol in women with mild-to-moderate pregnancy induced hypertension (PIH). DESIGN: Prospective double-blind randomised placebo controlled study. SETTING: Maternity units of five hospitals in the Trent Region. SUBJECTS: 144 women (86 primigravid) who developed PIH after 20 weeks gestation. INTERVENTIONS: Treatment with oral labetalol up to 600 mg daily or placebo with subsequent care of treatment failures in accordance with the attending obstetrician's practice. MAIN OUTCOME MEASURES: Number of days spent as an antenatal inpatient; the development of proteinuria; the perceived need for induction of labour or elective caesarean section; and gestation age at delivery. RESULTS: Labetalol significantly lowered the blood pressure and reduced the incidence of proteinuria. However, neither the number of days spent as an antenatal inpatient, nor the perceived need for induction of delivery or elective caesarean section, nor the gestation age at delivery differed significantly between the two treatment groups. Post-randomisation consideration of early (< or = 32 weeks) and late (> 32 weeks) onset groups showed the placebo treated early-onset group (n = 15) to have more patients with severe hypertension (> 150/110 mmHg) and a greater requirement for additional antihypertensive therapy prior to labour than the group treated with labetalol (n = 16). CONCLUSION: Anti-hypertensive intervention therapy in pregnancy induced hypertension has been examined using a placebo controlled randomised double-blind trial of labetalol in pregnancy. The maximum blood pressure prior to labour and the incidence of proteinuria was reduced in women on active therapy. However, the length of gestation was not significantly prolonged and indices of clinical outcome were not significantly altered. The appropriateness of pharmacological therapy for late-onset PIH may be questioned.
A randomized placebo-controlled study of the effect of low dose aspirin on platelet reactivity and serum thromboxane B2 production in non-pregnant women, in normal pregnancy, and in gestational hypertension.
OBJECTIVE: To investigate the effect of 60 mg aspirin daily on platelet reactivity and prostaglandin production in various groups of patients. Similar regimens, which are thought to act through inhibition of platelet thromboxane production, are currently undergoing clinical assessment for the prevention of pre-eclampsia and intrauterine growth retardation. DESIGN: A prospective randomized placebo controlled study. SETTING: University Hospital, Nottingham. SUBJECTS: 12 non-pregnant female volunteers, 18 normal primigravidae before 16 weeks gestation and 16 pregnant women admitted with gestational hypertension (GH) at a mean gestation of 38 weeks. INTERVENTIONS: In the non-pregnant women blood samples were taken before and after a 10-day course of 60 mg aspirin daily. The primigravidae had blood samples taken at 16 weeks and then they were randomized to receive either 60 mg aspirin daily or a matched placebo. Further blood samples were obtained at 28, 32 and 36 weeks. MAIN OUTCOME MEASURES: Changes in platelet reactivity and release reaction, and serum thromboxane production, were estimated in whole blood. RESULTS: 60 mg aspirin daily significantly inhibited cyclo-oxygenase dependent platelet aggregation, release reaction and serum thromboxane production in non-pregnant and pregnant women, and in women with GH (P less than 0.01). When adrenaline was used as the aggregating agent, the cyclo-oxygenase pathway was recruited in the increased reactivity seen in the third trimester of normal pregnancy, and was sensitive to inhibition by low dose aspirin. CONCLUSION: Low dose aspirin would appear to be an appropriate agent for the inhibition of platelet reactivity associated with hypertensive pregnancy.
Calcium and platelets in normotensive and hypertensive human pregnancy.
OBJECTIVES: The primary objective of this study was to determine the baseline platelet intracellular free Ca2+ concentration in normotensive and hypertensive primigravid women and to note any correlation between variables (ie. platelet intracellular free Ca2+ concentration and arterial blood pressure). DESIGN: A cross-sectional study of 24 normotensive and 36 primiparous women whose pregnancies were complicated by gestational hypertension, in the third trimester. METHODS: Platelet intracellular free Ca2+, serum Ca2+, and renal clearance of Ca2+ were recorded. RESULTS: Mean platelet intracellular free Ca2+ concentration was significantly increased in those subjects whose pregnancies were complicated by proteinuric gestational hypertension (pre-eclampsia) compared with the normotensive primiparous control sample. Those subjects with non-proteinuric pregnancy-induced hypertension did not show this significant increase in baseline platelet intracellular free Ca2+ concentration despite having a persistent and statistically significantly elevated systemic arterial blood pressure. On pooling these data for both normotensive and hypertensive primigravidae a significant positive correlation was noted between the variables of platelet intracellular free Ca2+ concentration and arterial blood pressure. The renal clearance of free Ca2+ was progressively reduced with increasing severity of the disease but had returned to normal 6 weeks postpartum. Serum Ca2+ concentrations corrected for albumin were however higher in the hypertensive patients. CONCLUSION: Transmembrane Ca2+ fluxes are altered in hypertensive pregnancy by a specific mechanism, probably of placental origin.
Adaptation of pulse oximetry for fetal monitoring during labour.
Application of pulse oximetry to intrapartum monitoring was investigated in 105 women. No adequate reading could be obtained in 44 cases. Two major sources of artifact, related to probe apposition and signal processing, were identified and excluded. The average arterial oxygen saturation from the fetal scalp was 82% (SD 6%), which is higher than has been inferred from pO2 levels. Readings below 60% or the development of an unstable baseline suggest the presence of substantial hypoxia and acidosis.
Platelet angiotensin II binding sites in normotensive and hypertensive women.
Specific binding of angiotensin II (AII) to platelets was measured in 89 women, 25 nulliparous non-pregnant women and 64 primigravida in the third trimester of pregnancy. There was significantly lower binding in the 25 pregnant women who were normotensive (2.3 fmol/10(9) cells) when compared with the non-pregnant women (9.0 fmol/10(9) cells P less than 0.001). Significantly higher platelet AII binding levels were found in the 39 women who had pregnancy induced hypertension (PIH) (5.5 fmol/10(9) cells) when compared with the 25 normotensive pregnant women (P less than 0.001). Of the 39 women with PIH, platelet AII binding was higher in the 23 women who had pre-eclampsia (7.0 fmol/10(9) cells), when compared with the 16 who had non-proteinuric PIH, (4.6 fmol/10(9) cells) although the difference was not statistically significant (P less than 0.04). The pressor response to AII is also diminished in pregnancy, yet less so if pregnancy induced hypertension develops. Platelets may provide a readily accessible tissue with which to study AII responsiveness in pregnancy.
Atrial natriuretic peptide and atrial size during normal pregnancy.
Plasma atrial natriuretic peptide (ANP), right and left atrial areas and the diameter of the left atrium were studied serially during normal pregnancy and at 6 weeks post partum in 21 nulliparous women. Concentrations of ANP in plasma were significantly elevated during mid-pregnancy. Thereafter ANP levels were not significantly different from those at 6 weeks after delivery. All atrial measurements were significantly increased in the third trimester of pregnancy, but none was significantly correlated with the plasma ANP concentrations. This might point at an altered mechanism of ANP secretion, which may be part of a physiological adaptive process to sustain the hypervolaemia of pregnancy.
Atrial natriuretic peptide and atrial size during normal pregnancy.
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Platelet reactivity and serum thromboxane B2 production in whole blood in gestational hypertension and pre-eclampsia.
OBJECTIVE: To determine the nature and extent of changes in platelet reactivity in gestational hypertension and pre-eclampsia (using whole blood techniques which may be more physiological than those previously employed). DESIGN: Cross-sectional observational study. SUBJECTS: 8 normal primigravidae, 16 women with gestational hypertension and 12 women with pre-eclampsia, studied at around 36 weeks gestation. RESULTS: Platelet reactivity (aggregation and release reaction) induced by stimulation with adrenaline was decreased in the pre-eclamptic group. Serum thromboxane B2 production was unchanged in both hypertensive groups compared with the control group. CONCLUSIONS: In the context of evidence of platelet activation in pre-eclampsia, our findings are interpreted as reflecting platelet exhaustion.
Natural history determinants of the time constants of the fetal electrocardiogram.
A total of 92 fetuses have been studied during labour using a technique of real-time fetal electrocardiography. This study showed differences in the PR and QRS intervals between male and female infants and also confirmed previous findings of a positive correlation between QRS width and fetal birthweight. The importance of taking natural biological factors into account in the interpretation of the time constants of the FECG is demonstrated.
Echo-planar imaging of the human fetus in utero.
We have demonstrated that echo-planar imaging can be used to produce high-quality snapshot images of the human fetus in utero in a fraction of a second. These images are free of motional artifact or blurring and allow detailed depiction of fetal structures in normal and pathological pregnancies.
A prospective evaluation of OC125 and magnetic resonance imaging in patients with ovarian carcinoma.
Eighteen patients with suspected primary or recurrent ovarian carcinoma have been investigated in each case by the assay of serum levels of the antigen CA125, immunoscintigraphy using 131I-OC125 antibody and magnetic resonance imaging using a 0.15 Tesla system. The final diagnosis was confirmed by laparotomy or laparoscopy. Serum levels of CA125 ranged between 5 and 780 units/ml (normal range less than 35). Antibody images and MRI were truly positive in 11 patients, 2 of whom were subsequently found to have bowel tumours. MRI showed greater detail of smaller lesions whilst immunoscintigraphy was more suited to the detection of distant metastases. In 7 patients the antibody images were positive whilst the serum marker levels were normal. This pilot study provides a preliminary comparison of the more recent techniques currently being evaluated for the detection of ovarian carcinoma.