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Biomedical subjects

E M Symonds

Publications and source records attributed to E M Symonds.

At least 73 records · Page 4Linked to original sources
PubMed1990

Echo planar imaging of the human fetus in utero at 0.5 T.

The snap-shot capability of the echo-planar imaging technique is used to freeze motion effectively in human fetal studies in utero. These first results obtained at 0.5 T demonstrate diagnostic quality images without the need for averaging. Although averaging improves the image signal to noise ratio, it is shown that significant image blurring is produced even when only eight separate images are averaged over a period of a few seconds. Results are presented showing anatomical detail of the internal organs of the fetus. Some pathology is also demonstrated. These results were obtained using the modulus blipped echo-planar single-pulse technique (MBEST). Running at 10 frames/second, the modulus version of the fast low-angle excitation echo-planar technique (FLEET) is used to produce ungated fetal cardiac movies.

Female↗
PubMed1990

Studies on the human ovarian renin-angiotensin system: optimization of assay methodology and effects of follicular stimulants.

The renal and genital tracts share a common embryological origin; it is thus not surprising that tissues from both can synthesize renin. Preliminary studies showed extremely high concentrations of renin in follicular fluid (FRC) following ovarian stimulation for in-vitro fertilization. This necessitated complete revalidation of the renin assays and showed that data obtained using commercial kits were invalid. An assay protocol was developed using a 1:2 dilution of follicular fluid taken into EDTA (0.3 mol/l) and o-phenanthroline (0.05 mol/l). The assay was performed at pH 7.5 in the presence of excess exogenous (sheep) renin substrate, with incubation periods of 5, 10 and 15 min at 37 degrees C. This protocol resulted in the linear generation of angiotensin I (AI). Activation of inactive renin was performed using eightfold more trypsin than was required for plasma samples. Follicular renin substrate concentrations (FRS) were measured using the same assay methodology as used for measurement of plasma renin substrate concentrations (PRS). Storage of samples at -18 degrees C for up to 2 months was found not to affect the FRC, although repeated freeze-thaw cycles did. FRC and plasma renin concentrations (PRC) were very similar in 25 unstimulated control women, studied in the follicular phase of the menstrual cycle. Trypsin activation increased follicular total renin concentration (FTRC) more than plasma total renin concentration (PTRC) (P less than 0.0001). FRS was slightly higher than PRS (P less than 0.02). Ovarian stimulation with clomiphene citrate (CC; six women) was without effect on these parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin I↗
PubMed1989

Nottingham mothers stop smoking project -- baseline survey of smoking in pregnancy.

In the largest survey of smoking in pregnancy to date in the United Kingdom, 3882 women attending the two antenatal clinics in Nottingham during July and August 1986, were asked about their smoking habits. Thirty-seven per cent of pregnant women were smoking and only one in four of these was successful at stopping at some point during pregnancy. However, 55 per cent of the mothers who smoked at the start of pregnancy claimed to smoke less during pregnancy. No change was reported in the habits of one-quarter of the mothers who smoked during pregnancy and this proportion may represent an 'irreducible minimum'. Mothers were more likely to continue to smoke if younger (14-20 years), single, living with a partner who smoked, who left school at 16 years and were from manual working families. Those who succeeded in giving up smoking during pregnancy were more likely to be from professional and managerial families. Antenatal booklets about the dangers of smoking were the source of information cited most frequently. Half of the smoking mothers claimed not to have received advice from their family practitioners about the hazards of smoking nor information about how to give up the habit. Even fewer received such advice from hospital doctors, or midwives. This represents a major challenge to professional training in health education.

Adolescent↗
PubMed1989

Intraperitoneal 131I- and 111In-791T/36 monoclonal antibody in recurrent ovarian cancer: imaging and biodistribution.

An examination of the biokinetics and biodistribution of i.p. administered 131I- or 111In-labelled 791T/36 antibody (1 mg) has been carried out in five patients with stage III/IV ovarian cancer. Blood kinetics and urinary excretion of the radiolabels were assayed. Scintigraphy was performed immediately following administration and before and after peritoneal lavage at 48 h. Blood levels of both preparations rose over the first 20-40 h reaching 8-14% of the administered dose in the circulation and then declined (T1/2 of 40 h). Circulating radiolabel was still attached partially to antibody as shown by precipitation with anti-mouse IgG antiserum. The rapid appearance of radiolabel in the bloodstream meant that any tumour localization could be from circulating antibody rather than local infiltration. Interpretation of the images was difficult and the distribution of the tracer was different from that previously observed using i.v. administration of antibody. In some cases the images were confusing and the uptake of activity did not fit in with the clinical knowledge of the disease or the findings from laparoscopy. Tumour specimens resected at 4-5 days showed up to 0.02% of the dose g-1.

Adult↗
PubMed1989

Bleeding as a consequence of chorion villus sampling.

A series of 4 separate studies were conducted to assess the incidence and short term consequence of bleeding associated with chorion villus sampling. Results support previous reports that risk of foetal-maternal transfusion as suggested by a rise in maternal serum alpha-fetoprotein (MSAFP) can occur. This occurrence is not consistent and need not be obvious even after therapeutic abortion. It is also transient and did not complicate mid-trimester neural tube screening or subsequent course of pregnancy. Eighty-seven percent of blood contaminating villus samples are of maternal origin. Following diagnosis 37% of patients reported some vaginal bleeding. This is mainly in the form of spotting which did not preclude normal pregnancy. Foetal loss occurred in 4 of the patients when bleeding considered heavier than spotting continued. In rhesus negative patients prophylactic anti-D gamma-globulin is advised, since neither Kleihauer counts nor MSAFP estimation reliably detect all foetal-maternal transfusions.

Chorionic Villi Sampling↗
PubMed1989

The fetal outcome in a randomized double-blind controlled trial of labetalol versus placebo in pregnancy-induced hypertension.

The effects of labetalol were compared with those of placebo in a multicentre randomized double-blind and prospective study of 152 patients with mild to moderate, non-proteinuric pregnancy-induced hypertension. Labetalol in a dose of 100 mg three times daily, increasing to 200 mg three times daily where required, significantly reduced maternal mean arterial pressure. There was some reduction in preterm delivery, neonatal respiratory distress syndrome and jaundice in the labetalol-treated group. Intrauterine growth retardation and neonatal hypoglycaemia occurred with the same frequency in both groups. There were no perinatal deaths. Labetalol appears to be an effective agent in the management of mild to moderate pregnancy-induced hypertension. The data from this study suggest possible advantages and no apparent disadvantages for the fetus during its use.

Adult↗
PubMed1989

Abdominal pain of unknown aetiology in pregnancy.

The outcome of 140 pregnancies complicated by unexplained abdominal pain was compared with that in a comparison group of 280 women who gave birth at the same time. The two groups were comparable for maternal age and parity but the study group contained a significantly higher proportion of smokers, unmarried women, and women whose partners were unemployed (P less than 0.001). All the pregnancies resulted in livebirths. There were no statistically significant differences in birthweight, gestational age at delivery or mode of delivery between the two groups.

Abdominal Pain↗
PubMed1989

Blindness in eclampsia: CT and MR imaging.

Three cases of cortical blindness complicating eclampsia are described, with magnetic resonance imaging (MRI) and X-ray computed tomography (CT). The correspondence of MRI lesions (hyperintense on T2 weighted, and hypointense on T1 weighted sections) and low attenuation lesions on CT scan indicated ischaemia rather than haemorrhage as the pathological mechanism.

Adult↗
PubMed1988

The effects of intravenous angiotensin II upon blood pressure and sodium and urate excretion in human pregnancy.

Twelve women in their first 3 months of pregnancy received an i.v. saline load (3 mmol sodium/kg) and a graded infusion of angiotensin II (Ang II; i.e. 4, 8 and 16 ng/kg per min). As controls, twelve comparable pregnant subjects received the saline infusion alone. Eight non-pregnant women underwent both protocols, with doses of 2, 4 and 8 ng/kg per min Ang II, and thus acted as their own controls. Saline loading evoked proportionately similar falls in basal plasma renin (PRC) and plasma aldosterone (PAC) concentrations in pregnant and non-pregnant women. Angiotensin II evoked a dose-dependent pressor response, a graded increase in PAC and a reduction in sodium and urate excretion in both pregnant and non-pregnant women. The administration of Ang II had a proportionately greater effect on sodium and urate excretion in non-pregnant than in pregnant women; the pressor response to Ang II was also decreased in the pregnant women. The stimulation of PAC by Ang II, however, did not differ between the two groups. These results show that refractoriness to the renal and vascular effects of Ang II is present as early as the eleventh week of gestation. They also support the hypothesis that there is a degree of dissociation between the renin-angiotensin system and PAC in normal pregnancy.

Adult↗
PubMed1988

Magnetic resonance imaging (MRI) in obstetrics. I. Maternal anatomy.

We assessed the ability of magnetic resonance, a recently introduced imaging technique, to demonstrate the maternal anatomy in obstetrics. The signal intensity of different maternal tissues using T1 and T2 weighted sequences was examined. The bony pelvis is depicted with sufficient clarity to provide an alternative to conventional X-ray pelvimetry. The placenta and cervix have a distinctive appearance facilitating the diagnosis of placenta praevia. The unique demonstration of cervical morphology will offer the potential for investigation into the ill-understood conditions of cervical dystocia and cervical incompetence.

Cervix Uteri↗
PubMed1988

Magnetic resonance imaging (MRI) in obstetrics. II. Fetal anatomy.

Magnetic resonance imaging (MRI) was performed in 36 patients at between 10 and 38 weeks gestation to determine the fetal anatomy that could be identified at different gestations. Fetal motion significantly degraded the image quality in the first and second trimesters, but in the final trimester fetal anatomy was clearly demonstrated. T2 weighted sequences showed the fetal brain and lungs to have a high signal intensity. Shorter TR leading to a T1 weighting gave better resolution of the overall anatomy. MRI has revealed the potential for assessment of lung maturity and the growth-retarded fetus.

Brain↗
PubMed1988

Magnetic resonance imaging of benign ovarian masses.

Forty-one patients with 45 pelvic mass lesions were assessed by magnetic resonance imaging (MRI). All lesions were initially considered to be benign ovarian masses with this diagnosis confirmed in 36 lesions. The characteristics on MRI are analysed and features useful in predicting histological type identified. Our results indicate that a high, though not absolute, level of diagnostic specificity should be obtainable in identification of ovarian pathology.

Adenofibroma↗