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Biomedical subjects

C W Redman

Publications and source records attributed to C W Redman.

At least 73 records · Page 4Linked to original sources
PubMed1997

Maternal middle cerebral artery velocimetry in normal pregnancy and postpartum.

OBJECTIVE: To study changes throughout gestation and the puerperium of middle cerebral artery flow velocity waveforms obtained by transcranial Doppler ultrasound. DESIGN: Prospective, observational study. SETTING: John Radcliffe Maternity Hospital, Oxford, UK. PARTICIPANTS AND METHODS: Middle cerebral artery velocities were measured by transcranial Doppler ultrasound in 25 nonpregnant women, 22 women longitudinally followed throughout pregnancy and 21 women serially studied from delivery until the late puerperium. MAIN OUTCOME MEASURES: Transcranial Doppler changes in pregnancy and the puerperium. RESULTS: The transcranial Doppler ultrasound measurements showed good reproducibility. Signals from one middle cerebral artery could not be obtained in 4.6% of the examinations, but otherwise readings were similar on both sides. Women in the second half of pregnancy had lower middle cerebral artery mean velocities than nonpregnant women. Velocities decreased with advancing gestation but increased in the immediate puerperium to levels comparable to those found in nonpregnant women. CONCLUSIONS: Transcranial Doppler ultrasound is a noninvasive technique suitable for studying maternal cerebral haemodynamics in pregnancy and postpartum. Middle cerebral artery mean velocity decreased with advancing gestation and increased to nonpregnant values in the immediate puerperium. These physiological changes need to be considered when comparing data with measurements taken in abnormal pregnancy states.

Adult↗
PubMed1997

Endometrial sampling and general practice.

Endometrial sampling is an 'office' technique that has gained widespread acceptance in the United States (US). It is as accurate as dilatation and curettage (D&C) in the diagnosis of endometrial atypia and carcinoma. It appears to be the most suitable method of endometrial assessment for general practice. It has the potential for the earlier detection of endometrial abnormality and for increasing the number of women with abnormal vaginal bleeding who can be wholly managed within primary care. However, research is lacking on the effect of the widespread introduction of the technique into general practice. This paper puts forward recommendations for the use of endometrial sampling by general practitioners (GPs) based on current evidence.

Biopsy↗
PubMed1996

Endothelial cell proliferation is suppressed by plasma but not serum from women with preeclampsia.

OBJECTIVES: Evidence has been sought for a circulating factor derived from the placenta that suppresses endothelial cell proliferation and hence contributes to the maternal endothelial cell disturbances of preeclampsia. STUDY DESIGN: The effects of sera and plasmas from women with proteinuric preeclampsia and from matched normal pregnant control women on endothelial cell proliferation were compared. The recovery of endothelial cell inhibitory activity from syncytiotrophoblast microvesicles added to male blood and prepared as plasma or serum was determined to investigate the possible placental origin of the inhibitory factor. RESULTS: Sera from women with preeclampsia did not inhibit endothelial cell proliferation. In contrast, plasma from preeclamptic women significantly suppressed endothelial cell growth at 20% dilution compared with controls, and suppression was more pronounced in severe preeclampsia. The inhibitory activity of syncytiotrophoblast microvesicles added to blood could not be recovered from serum, only from plasma, which may explain why there was no suppression with sera from preeclamptic women. CONCLUSIONS: These results confirm that there is a blood-borne endothelial cell suppressive factor in preeclampsia that may be derived from the placenta.

Adolescent↗
PubMed1996

A comparison of the inactive urinary kallikrein:creatinine ratio and the angiotensin sensitivity test for the prediction of pre-eclampsia.

OBJECTIVE: To determine the relation between the inactive urinary kallikrein: creatinine ratio (IUK:Cr) and the angiotensin sensitivity test (AST) at 28 weeks of gestation and to assess each as a screening test for pre-eclampsia. DESIGN: Prospective interventional study. SUBJECTS: Four hundred and fifty-nine normotensive nulliparous women recruited from hospital antenatal clinics. SETTING: John Radcliffe Maternity Hospital, Oxford, and Queen Charlotte's and Chelsea Hospital, London. INTERVENTIONS: A urine sample for IUK:Cr measurement was provided before performing the AST at 28 weeks of gestation. Those women who demonstrated increased sensitivity to angiotensin II were entered into a randomised placebo controlled trial of low dose aspirin for the prevention of pre-eclampsia (CLASP). MAIN OUTCOME MEASURES: The development of pre-eclampsia. RESULTS: The IUK:Cr ratio was significantly lower in those women who showed increased sensitivity to angiotensin II (P < 0.0001 Student's t test). The sensitivity and specificity for detecting pre-eclampsia were, respectively, 22% and 85% for the AST and 67% and 75% for the IUK:Cr. Low-dose aspirin (60 mg) had no effect on the pregnancy outcome. CONCLUSION: There appears to be some relation between the IUK:Cr and AST tests in pregnancy. However, in this population, the IUK:Cr ratio was a better screening test for pre-eclampsia than the AST, but overall neither test was a powerful predictor for the syndrome.

Angiotensin II↗
PubMed1996

Improvements in computerized fetal heart rate analysis antepartum.

The continued development of a computerised system for measuring the pattern of the antepartum fetal heart rate (FHR) is described. Previous work had established that measurement of FHR variation objectively detects chronic fetal hypoxaemia and the onset of metabolic acidaemia antepartum. The normal centiles were calculated for the amplitude of long-term FHR variation, in episodes of high and low variation, week by week from 24-42 weeks gestation. Reference to these (automatically by the computer) improved discrimination between normal and questionable records in 38% of records, with a small saving of time. Two types of sinusoidal rhythm were described (slow, 1 in 2-5 minutes, incidence 0.16% of subjects; and faster, 2-5 per minute, incidence 0.025%) with methods for their detection. Both may be of sufficient amplitude to induce an episode of high FHR variation. The different effects of maternal steroid (betamethasone or dexamethasone) administration of FHR variation were compared, and the clinical consequences considered. The frequency distribution of basal FHR in normal and abnormal records was measured, and the effects on basal FHR outside the normal range (120-160 bpm) on FHR variation described. Adjustment of the FHR baseline was undertaken when, exceptionally, large abrupt changes in heart rate occurred during a record. The duration and frequency of FHR record acquisition in clinical practice were reviewed, and new policies recommended. With adequate safeguards, measurement by a computer offers reliable objective information from which fetal health may be assessed, more objectively and accurately than by visual inspection.

Adrenal Cortex Hormones↗
PubMed1995

Expression of TAP1 by human trophoblast.

Successful placentation in the human is dependent on the trophoblast evading recognition and destruction by the maternal immune system. However, invasive cytotrophoblast express HLA-G which may be able to present peptide to T cells. Transporter proteins are essential for peptide presentation and major histocompatibility complex (MHC) class I assembly. We have determined their expression by trophoblast in relation to HLA-G, using immunohistochemistry. Anti-transporter protein antibody (TAP1) labeling closely paralleled that of MHC class I, but the intensity of its expression was much greater on the HLA-G+ extravillous cytotrophoblast than any other fetal or maternal tissue in the first trimester and at term. This suggests that the extravillous cytotrophoblast are very actively assembling MHC class I antigens with peptides. However, expression of MHC class I by the cytotrophoblast was not correspondingly elevated. This pattern could result from HLA-G being shed from the surface of the trophoblast, a process which may play a central role in protecting the fetus from maternal immune attack.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

The angiotensin sensitivity test and low-dose aspirin are ineffective methods to predict and prevent hypertensive disorders in nulliparous pregnancy.

OBJECTIVE: Our purpose was to assess the efficiency of the angiotensin sensitivity test as a predictive test for preeclampsia and the effectiveness of low-dose aspirin to prevent preeclampsia when commenced at 28 weeks' gestation in angiotensin II-sensitive women. STUDY DESIGN: A total of 495 healthy nulliparous women underwent the angiotensin sensitivity test at 28 weeks' gestation. The angiotensin II-sensitive women were randomized to 60 mg of aspirin or placebo as a subset of a large multicenter, randomized, controlled trial of low-dose aspirin therapy in pregnancy. Assessment of the efficiency of the angiotensin sensitivity test and low-dose aspirin in pregnancy was performed after detailed review of case notes after delivery. The Oxford definition of preeclampsia was used. This includes women without proteinuria but requires blood pressure increments that have been validated to bias the selection to primigravid women. RESULTS: Five women had proteinuric preeclampsia in the angiotensin II-sensitive group randomized to aspirin compared with none in the group randomized to placebo. Overall, 11 (25%) of the women randomized to aspirin had preeclampsia compared with four (11%) randomized to placebo (p < 0.05, not significant). The positive and negative predictive values for the angiotensin sensitivity test were 19% and 87%, respectively. CONCLUSION: The angiotensin sensitivity test is not an effective screening test for preeclampsia, and low-dose aspirin does not prevent preeclampsia when commenced at 28 weeks' gestation in angiotensin II-sensitive women.

Angiotensin II↗
PubMed1995

Platelet intracellular free calcium response to arginine vasopressin is similar in preeclampsia and normal pregnancy.

OBJECTIVE: Our purpose was to compare the effect of arginine vasopressin stimulation on platelet free intracellular calcium levels in normal pregnancy, incipient preeclampsia, and established preeclampsia. STUDY DESIGN: Cross-sectional and prospective observational study designs were used. Platelet free intracellular calcium was measured by flow cytometry in 10 nonpregnant female volunteers, 10 women with established preeclampsia and their normal pregnant matched controls, and 64 normal pregnant women at 28 weeks' gestation. All pregnant women were nulliparous. RESULTS: Increased response to arginine vasopressin stimulation was observed in nonpregnant compared with pregnant women (p < 0.001). No differences were observed between women with normal pregnancy, incipient preeclampsia, or established preeclampsia. CONCLUSION: The platelet intracellular free calcium response to arginine vasopressin is not a feature of incipient or established preeclampsia. Therefore, in contrast to a previous report, it does not appear to have value as a predictive test for preeclampsia.

Adolescent↗
PubMed1995

Interleukin-6, tumour necrosis factor and soluble tumour necrosis factor receptors in women with pre-eclampsia.

OBJECTIVES: Generalised maternal endothelial cell dysfunction appears to be an underlying problem in pre-eclampsia presumed to be caused, directly or indirectly, by one or more circulating factors derived from the placenta. Recently it has been suggested that tumour necrosis factor (TNF) may play an important role in pre-eclampsia and contribute to endothelial activation. This study was designed to investigate this proposal. DESIGN: Plasma TNF-alpha, IL-6 and both forms of soluble TNF receptors (p55 and p75 TNF-R) have been measured by ELISA in 31 pre-eclamptic patients and 31 pregnant controls matched for age, parity and gestational age. RESULTS: Levels of IL-6, TNF-alpha and soluble TNF-R (p55 and p75) were significantly higher in pre-eclamptic patients, compared with age and gestation matched controls with a wide variation in levels between pre-eclamptic individuals. There was a correlation between levels of IL-6 and TNF or TNF-R and between TNF and TNF-R levels. However, when the pre-eclamptic patients were subdivided on the basis of the severity of their disease, the median values of plasma concentrations of IL-6, TNF-alpha and TNF-R were all higher in the group with lower platelet counts. CONCLUSIONS: These new findings are consistent with the concept that the maternal syndrome of pre-eclampsia is associated with endothelial dysfunction and provide evidence that at least part of this dysfunction could arise from excessive release of TNF-alpha into the circulation.

Adult↗
PubMed1995

Corticotrophin-releasing hormone and corticotrophin-releasing hormone binding protein in normal and pre-eclamptic human pregnancies.

OBJECTIVE: To measure the plasma levels of corticotrophin-releasing hormone and corticotrophin-releasing hormone binding protein in normal pregnancy and in pregnancies complicated by pre-eclampsia. SETTING: John Radcliffe Hospital, Oxford and St Thomas's Hospital, London. SUBJECTS: One hundred and twenty pregnant women sampled prospectively throughout gestation, of whom 91 experienced a normal pregnancy and eight developed pre-eclampsia; in a second study, 10 women with severe pre-eclampsia, presenting at a range of gestational ages, were sampled once and compared with appropriately matched normal pregnant women. MAIN OUTCOME MEASURE: Plasma levels of corticotrophin-releasing hormone determined by immunoradiometric assay. Plasma levels of corticotrophin-releasing hormone binding protein measured by direct radioimmunoassay. RESULTS: In the prospective study, plasma samples from women with pre-eclampsia exhibited higher (390.2 versus 292.7 pmol/l at 36 weeks) levels of corticotrophin-releasing hormone and significantly lower (5.24 versus 8.14 nmol/l at 36 weeks, P < 0.002) levels of corticotrophin-releasing hormone binding protein than normal controls. In the second, single time point study a significant elevation in CRH (P < 0.002) and reduction in CRH-BP (P < 0.001) was found in pre-eclamptic pregnancies compared with controls. CONCLUSIONS: In human pregnancies complicated by pre-eclampsia there is an elevated level of corticotrophin releasing hormone whilst there is less corticotrophin-releasing hormone binding protein; therefore there is a net increase in free potentially bioactive hormone which may play a role in the pathology of the disease.

Adolescent↗
PubMed1994

Eclampsia in the United Kingdom.

OBJECTIVES: To measure the incidence of eclampsia, establish how often it is preceded by signs of pre-eclampsia, document the morbidity associated with eclampsia, and determine the maternal case fatality rates. DESIGN: A prospective, descriptive study of every case of eclampsia in the United Kingdom in 1992. Information was collected from reviews of hospital case notes and questionnaires to general practitioners. SETTING: All 279 hospitals in the United Kingdom with a consultant obstetric unit. RESULTS: Obstetricians and midwives notified 582 possible cases, and 383 were confirmed as eclampsia. The national incidence of eclampsia was 4.9/10,000 maternities (95% confidence interval 4.5 to 5.4). Most convulsions occurred despite antenatal care (70%) and within one week of the woman's last visit to a doctor or midwife (85%). Three quarters of first seizures occurred in hospital, of which 38% developed before both proteinuria and hypertension had been documented. Forty four per cent of cases occurred postpartum, more than a third (38%) antepartum, and the remainder (18%) intrapartum. Nearly one in 50 women (1.8%) died, and 35% of all women had at least one major complication. The rate of stillbirths and neonatal deaths was 22.2/1000 and 34.1/1000, respectively. Preterm eclampsia occurred more commonly antepartum and was associated with more maternal complications and fetuses that were small for gestational age, as well as with higher rates of stillbirth and neonatal mortality. Antepartum eclampsia, which was more likely to occur preterm, was associated with a higher rate of maternal complications and a higher neonatal mortality. Both factors (gestational prematurity and antepartum occurrence) contributed independently to the severity of the outcome. CONCLUSION: Eclampsia occurs in nearly one in 2000 maternities in the United Kingdom and is associated with high maternal morbidity and fatality in cases. It may present unheralded by warning signs. Preterm and antenatal eclampsia seem to be particularly severe.

Adolescent↗