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Biomedical subjects

J R Higgins

Publications and source records attributed to J R Higgins.

At least 19 recordsLinked to original sources
PubMed2002

The relation between maternal work, ambulatory blood pressure, and pregnancy hypertension.

STUDY OBJECTIVE: The purpose of the study was to determine the relations between maternal work, ambulatory blood pressure in mid-pregnancy, and subsequent pregnancy outcome. DESIGN: Data were studied on 933 healthy normotensive primigravidas who had been enrolled into a study on the predictive value of ambulatory blood pressure measurement performed between 18 and 24 weeks gestation. They were classified into three groups depending on whether they were at work (working group, n=245), not working (not working group, n=289), or normally employed but chose not to work (ENK group, n=399), on the day monitoring was performed. SETTING: The Rotunda Hospital (a large maternity hospital), Dublin, Ireland. MAIN RESULTS: Adjusted for age, body mass index, smoking, drinking, and marital status, women at work had higher mean daytime systolic (p<0.01) and diastolic (p<0.01) and 24 hour systolic pressures (p=0.03) compared with those not working. The rate of subsequent development of pre-eclampsia was significantly higher (odds ratio 4.1, 95% CI 1.1 to 15.2, p=0.03) among those at work compared with those not working. The association between pre-eclampsia and maternal work remained significant (odds ratio 5.5, 95% CI 1.1 to 27.8, p=0.04) even after allowing for the confounding factors of age, smoking, body mass index, and marital status. When daytime systolic and diastolic blood pressure were added to the regression analysis the risk ratios for pre-eclampsia remained high but did not quite reach statistical significance (odds ratio 4.7, 0.90 to 24.8, p=0.066). Birth weight and placental weight were not predicted by work status or blood pressure. CONCLUSIONS: A significant independent relation was found between maternal work and ambulatory blood pressure levels in mid-pregnancy. In addition, it was found that maternal work was significantly associated with the subsequent development of pre-eclampsia

Adult↗
PubMed2001

Optimizing stent expansion with new stent delivery systems.

OBJECTIVES: The purpose of this study was to assess whether the newer stent delivery systems provide a stented lumen cross-sectional area (CSA) that is equal to the delivery balloon nominal dimensions. BACKGROUND: First generation stents were often not adequately expanded with their delivery system and frequently required higher pressure or a larger balloon after deployment. Newer stents were designed to optimize expansion with noncompliant, high-pressure balloons provided as the delivery systems. METHODS: Intravascular ultrasound (IVUS) was used to evaluate 38 stents in 32 patients after deployment at 14 to 16 atm with their delivery balloon system. Minimum stent lumen CSA and stent minimum lumen diameter (MLD) were measured by IVUS imaging. The manufacturer's expected stent diameter was defined as the balloon diameter measured by the company at the maximum pressure used. The manufacturer's expected stent area was calculated based on the manufacturer's expected stent diameter. RESULTS: The MLD (2.5 +/- 0.5 mm) and minimum stent CSA (6.0 +/- 1.7 mm(2)) by IVUS were significantly smaller than the manufacturer's expected stent diameter (3.5 +/- 0.4 mm) and area (9.5 +/- 1.9 mm(2)) (p < 0.0001, respectively). The mean MLD by IVUS was 72 +/- 8% of the expected stent diameter, and the mean minimum stent CSA by IVUS was 62 +/- 10% of the expected stent area. CONCLUSIONS: Despite moderately high-pressure inflations, the mean minimum stent CSA actually achieved was, on average, only 62% of the manufacturer's expected stent area. To optimize stent deployment, these IVUS observations should be considered during coronary artery stenting.

Aged↗
PubMed2001

Anticoagulation in pregnancy and the puerperium.

For the management of acute thrombotic events in pregnancy therapeutic doses of low molecular weight heparins (LMWH) may be used, unless the shorter half-life of intravenous unfractionated heparin (UH) and predictable reversibility by protamine are important. Treatment should be continued up until delivery and into the puerperium. Pregnant women who have had an acute thrombotic event should be delivered by a specialist team. In the case of recent thrombosis, delivery should be planned and the time during which anticoagulation therapy is ceased around the time of delivery should be minimised. Therapeutic doses of LMWH contraindicate the use of regional anaesthesia, and a switch to intravenous UH before delivery may allow greater flexibility in this regard. Prophylactic doses of LMWH can be used to reduce the risk of recurrent thromboembolic events in pregnancy. The regimen used will depend on the previous history, the family history and the presence of risk factors, including the genetic and acquired causes of thrombophilia. Women with mechanical heart valves are at high risk during pregnancy and require therapeutic anticoagulation throughout pregnancy under the direction of experienced specialists. Low-dose aspirin can reduce the risk of recurrent pre-eclampsia by about 15%, but the role of UH and LMWH in the prevention of recurrent miscarriage or obstetric complications associated with uteroplacental insufficiency is still uncertain.

Anesthesia, Obstetrical↗
PubMed2001

Blood-pressure measurement and classification in pregnancy.

Pre-eclampsia is usually defined on the basis of new onset hypertension and albuminuria developing after 20 weeks of pregnancy. There are difficulties with measurement of these variables. Conventional sphygmomanometry remains the gold standard for blood-pressure measurement. The value of ambulatory blood-pressure measurement has yet to be established. Oedema is now omitted from all definitions of preeclampsia, although the finding of widespread severe oedema of sudden onset should not be ignored for clinical purposes. Definitions of pre-eclampsia based solely on hypertension and proteinuria ignore the wide clinical variability in this syndrome. Women with no proteinuria but who do have hypertension and other features such as severe headache or other symptoms, thrombocytopenia, hyperuricaemia, disordered liver function, and fetal compromise are likely to have pre-eclampsia. This notion is accepted in the new Australasian definition of pre-eclampsia and more than hinted at in the new American College of Obstetricians and Gynecologists' definition. Definitions used for clinical purposes should be as safe as practical; they are likely to include a considerable number of false positives. Most research studies are weakened if patients without the disease are included. Therefore, a separate stringent research definition of pre-eclampsia we also suggest.

Blood Pressure Monitoring, Ambulatory↗
PubMed2001

Blood pressure in late pregnancy and work outside the home.

OBJECTIVE: To assess maternal blood pressure (BP) responses to working outside the home in late pregnancy, using 24-hour ambulatory BP monitoring. METHODS: Our paired observational study involved 24-hour ambulatory BP monitoring of 100 normotensive women (51 primiparas, 49 multiparas) on work and nonwork days. Mean BP differences were calculated for working, postworking, sleeping, and 24-hour periods on both days. Main outcome measures were BP differences between work and nonwork days and subsequent pregnancy hypertension. Comparisons in BP between work and nonwork days were done with Student paired t test. Comparisons between study subgroups were done with unpaired t test. Potential predictors of change in BP were examined using multiple linear regression. RESULTS: During job time, BP was significantly higher on work days than on nonwork days. The mean increase in BP associated with work was 2.6 mmHg (systolic BP, P <.001), 2.8 mmHg (diastolic BP, P <.001), and 2.9 mmHg (mean arterial BP, P <.001). Those observations were independent of parity. More than 10% of our subjects had increased mean arterial BP of 10 mmHg or more during job time on work days compared with nonwork days. Higher absolute BP levels (regression coefficient 0.21, P =.04) and greater perceived job stress (regression coefficient 1.34, P =.04) correlated positively with BP increases at work. Twelve women developed hypertension. Those women had a larger increase on work days in mean systolic (6.6 mmHg compared with 2.1 mmHg, P =.013), mean diastolic (6.4 mmHg compared with 2.3 mmHg, P =.014), and mean arterial (7.4 mmHg compared with 2.3 mmHg, P =.002) BP compared with normotensive women. The magnitude of BP responses to work was a significant predictor of pregnancy hypertension, independent of absolute BP level. CONCLUSION: Blood pressure increased in women when they worked outside the home. The effect of maternal work is important when treating pregnancy hypertension. Ambulatory BP monitoring makes assessment of maternal BP responses to work a practical clinical option.

Adult↗
PubMed2000

The relationship between increased folate catabolism and the increased requirement for folate in pregnancy.

OBJECTIVES: To estimate the rate of folate catabolism in pregnant and nonpregnant women and to derive the recommended dietary allowance for folate. DESIGN: Prospective, observational study. SETTING: Rotunda Hospital, Dublin. WOMEN: Twenty-four healthy gravid women were studied once during each trimester and postpartum. Twenty-five nonpregnant controls were assessed before and after folic acid supplementation. INTERVENTIONS: Women provided 24-hour urine collections while adhering to a strict dietary regimen containing no exogenous folate catabolites. MAIN OUTCOME MEASURES: Urinary levels of p-acetamidobenzoylglutamate and p-aminobenzoylglutamate were measured by high pressure liquid chromatography. RESULTS: The 24-hour excretion of folate catabolites, expressed as mean [95% CI] folate equivalents in microg) progressively increased during pregnancy. A peak was reached in the third trimester (349.1 microg [308.1 to 390.1]) where the rate was more than twice the rate in the nonpregnant control group (136.4 microg [112.4 to 160.4]) (P < 0.001). Based on our results the recommended dietary allowance for folate in nonpregnant women should be 250 microg and this should rise during pregnancy to 430 microg in the second trimester and 540 microg in the third trimester. CONCLUSIONS: The rate of folate catabolism progressively increases during pregnancy reaching a peak in the third trimester at the time of maximal fetal growth. The increased demand for folate during pregnancy appears to be due to the accelerated breakdown of the vitamin because of its participation in cellular biosynthesis. These results provide a quantitative basis for the current debate on the appropriate recommended dietary allowance for folate in both pregnant and nonpregnant women.

4-Aminobenzoic Acid↗
PubMed2000

Management of essential thrombocythaemia during pregnancy.

Essential thrombocythaemia is a rare myeloproliferative disorder that often presents with haemorrhagic or thrombotic complications. It may be detected incidentally in an asymptomatic younger adult and there are only a few case reports of essential thrombocythaemia in pregnant women. The risks posed by essential thrombocythaemia during pregnancy and its optimal management are uncertain. To determine if there is increased incidence of obstetric complications seen in women who have essential thrombocythaemia, we collected a large case series from a number of tertiary obstetric units in Australia and New Zealand. There were 30 pregnancies in 12 women who had essential thrombocythaemia. There were 17 live births (57%), 7 stillbirths (23%), 5 miscarriages (17%) and 1 ectopic (3%). Five pregnancies were complicated by placental abruption. When the outcomes of those women who received treatment with aspirin or interferon were compared to those that did not receive any treatment, there was a trend towards a higher livebirth rate (79% v. 38%, p = 0.06). Seven women were treated with aspirin and 5 had successful outcomes with no fetal complications. Four women were treated with alpha-interferon which reduced their platelet counts and all had successful outcomes with no fetal complication. These findings suggest that there is a high incidence of miscarriage, stillbirth and abruption in women with essential thrombocythaemia. Their pregnancies should be carefully monitored. Treatment with low dose aspirin and/or the use of alpha-interferon may be associated with an improved pregnancy outcome.

Adult↗
PubMed2000

Prothrombin G20210A mutation: is it associated with pre-eclampsia?

OBJECTIVE: A strong independent association between the prothrombin G20210A gene mutation and pre-eclampsia has been reported in an Italian population. This result was not confirmed in a subsequent study in a Dutch population. The objective of this study was to further test the hypothesis that the prothrombin G20210A mutation is associated with pre-eclampsia/eclampsia. METHODS: Seventeen eclamptics and 67 pre-eclamptics were recruited from 34 multicase Australian/New Zealand families. An additional 105 unrelated pre-eclamptic/eclamptic women and 119 parous women were recruited as controls. RESULTS: The overall incidence for the prothrombin G20210A gene mutation in the pre-eclamptic group was 3.6% (95% CI 1.2-8.2%) which was not significantly different from the control group 2.5% (95% CI 0.5-7.2%) (p = 0.73, OR 1.44, 95% CI 0.34-6.17). CONCLUSION: This study provides little evidence of a significant relationship between the prothrombin G20210A gene mutation and pre-eclampsia. Based on our results, we do not recommend testing for the prothrombin G20210A mutation in the routine investigation of women with pre-eclampsia.

Adult↗
PubMed1999

Nitric oxide in the uteroplacental, fetoplacental, and peripheral circulations in preeclampsia.

OBJECTIVE: Altered production of nitric oxide by the vascular endothelium may influence the pathogenesis of preeclampsia. The aim of this study was to measure circulating levels of nitric oxide metabolites (nitrites) in the uteroplacental, fetoplacental, and peripheral circulation of preeclamptic pregnancies compared with normotensive controls. METHODS: Fifteen women with preeclampsia were compared with 16 women with normotensive pregnancies. At cesarean, blood samples were taken from the uterine vein draining the placental site, the umbilical vein, and the antecubital vein after delivery of the baby but before delivery of the placenta. Plasma nitrites were measured using the Greiss reaction after conversion of plasma nitrates to nitrites using nitrate reductase. RESULTS: Nitric oxide metabolites were higher in the uteroplacental (P < .01), fetoplacental (P < .001), and peripheral (P < .02) circulations in samples from preeclamptic pregnancies compared with control pregnancies. In samples from the fetoplacental circulation only, nitric oxide metabolite levels were negatively correlated with gestational age (r = -.489, P < .01) and birth weight (r = -.544, P < .004). Nitric oxide metabolite levels were not significantly correlated with blood pressure, placental weight, or maternal age. CONCLUSION: In established preeclampsia, production of nitric oxide was higher in the uteroplacental, fetoplacental, and peripheral circulation than in normotensive pregnancies. This increase may be part of a compensatory mechanism to offset the pathologic effects of preeclampsia.

Adult↗
PubMed1999

Alternative forms of a novel aspartyl protease gene are differentially expressed in human gestational tissues.

The aim of this study was to identify genes involved in human placentation. To do this, differential gene expression was assessed in the decidua (placental bed) from pre-eclamptic and normotensive pregnancies using the polymerase chain reaction (PCR)-based subtractive technique of representational difference analysis. A novel aspartyl protease (cathepsin D-like) cDNA sequence was isolated by virtue of its over-expression in the pre-eclamptic decidual sample tested. It was designated DAP-1 (for Decidual Aspartyl Protease 1). Using DAP-1 primer sequences a second cDNA (DAP-2) was subsequently isolated from decidual RNA by reverse transcription (RT)-PCR and found to be identical to DAP-1 apart from 80 additional and consecutive base pairs in the N-terminal coding region. In DAP-2, a stop codon within the unique 80 bp sequence was predicted to terminate translation immediately before the consensus active site residues. While Southern blotting was used to show that there are two loci with homology to DAP-1 in the human genome, it is postulated that alternative pre-mRNA splicing of the 80 bp exon is involved in the regulated expression of active (DAP-1) and inactive (DAP-2) forms of this novel protease; a mechanism similar to that involved in the regulated expression of Caspase-2, a protease involved in apoptosis. In other systems the regulation of alternative splicing is indicated by tissue specificity and developmental stage specificity of the various spliced products. In this context it was demonstrated that whereas DAP-1 was the major transcript expressed in decidua, the pattern was reversed in the adjacent placental tissue. It is proposed that tissue and developmental stage-specific expression of the DAP protease are important for the normal development and function of the uteroplacental tissues and that dysregulation of the control of DAP gene splicing may play a role in abnormal placentation, like that seen in pre-eclampsia.

Alternative Splicing↗
PubMed1998

The diastolic debate: is it time to discard Korotkoff phase IV in favour of phase V for blood pressure measurements in pregnancy?

Current guidelines recommend using Korotkoff phase IV for measuring diastolic blood pressure in pregnant women. However, phase IV does not approximate "true" blood pressure as closely as phase V, is more difficult to detect, and has limited reproducibility. Many practitioners use phase V despite the guidelines. Universal adoption of phase V would improve the reliability of blood pressure measurements.

Blood Pressure↗
PubMed1998

Circulating vascular cell adhesion molecule-1 in pre-eclampsia, gestational hypertension, and normal pregnancy: evidence of selective dysregulation of vascular cell adhesion molecule-1 homeostasis in pre-eclampsia.

OBJECTIVE: Our purpose was to investigate circulating levels of vascular cell adhesion molecule-1 in the peripheral and uteroplacental circulations during normotensive and hypertensive pregnancies. STUDY DESIGN: This prospective observational study involved 2 patient groups. Group 1 consisted of 22 women with pre-eclampsia and 30 normotensive women followed up longitudinally through pregnancy and post partum. There were an additional 13 women with established gestational hypertension. Group 2 consisted of 20 women with established pre-eclampsia and 19 normotensive control subjects undergoing cesarean delivery. Plasma levels of vascular cell adhesion molecule-1 were measured in blood drawn from the antecubital vein (group 1) and from both the antecubital and uterine veins (group 2). Data were analyzed by analysis of variance. RESULTS: In group 1 vascular cell adhesion molecule-1 levels did not change significantly throughout normal pregnancy and post partum. Women with established pre-eclampsia had increased vascular cell adhesion molecule-1 levels compared with the normotensive pregnancy group (P = .01). Vascular cell adhesion molecule-1 levels were not elevated in women with established gestational hypertension. In group 2 significantly higher levels of vascular cell adhesion molecule-1 were detected in the uteroplacental (P < .0001) and peripheral (P < .0001) circulations of pre-eclamptic women by comparison with normotensive women. In the pre-eclamptic group there was a tendency toward higher vascular cell adhesion molecule-1 levels in the peripheral circulation than in the uteroplacental circulation (P = .06). In contrast to vascular cell adhesion molecule-1, circulating levels of E-selectin and intercellular adhesion molecule-1, other major leukocyte adhesion molecules expressed by the endothelium, were not different in pre-eclamptic and normotensive pregnancies. CONCLUSION: Established pre-eclampsia is characterized by selective dysregulation of vascular cell adhesion molecule-1 homeostasis. This event is not an early preclinical feature of pre-eclampsia, does not persist post partum, is not a feature of nonproteinuric gestational hypertension, and is not observed with other major leukocyte adhesion molecules. Induction of vascular cell adhesion molecule-1 expression in pre-eclampsia may contribute to leukocyte-mediated tissue injury in this condition or may reflect perturbation of other, previously unrecognized, functions of this molecule in pregnancy.

Adult↗
PubMed1998

Hemostasis in the uteroplacental and peripheral circulations in normotensive and pre-eclamptic pregnancies.

OBJECTIVE: Our purpose was to determine the hemostatic changes in the uteroplacental and peripheral circulations in normotensive and pre-eclamptic pregnancies. STUDY DESIGN: This prospective, observational study involved 2 patient groups. Group 1 consisted of 30 normotensive women and 22 women with pre-eclampsia who were followed up longitudinally through pregnancy and post partum. Group 2 consisted of 20 women with established pre-eclampsia and 19 normotensive control subjects, all undergoing cesarean section. Plasma levels of thrombin-antithrombin III complex, soluble fibrin, plasmin-alpha2-antiplasmin complex, and fibrin-degradation product (D-dimer) were measured in blood drawn from the antecubital vein (group 1) and from both the antecubital and uterine veins (group 2). Data were analyzed by analysis of variance. RESULTS: In group 1 levels of thrombin-antithrombin III complex, soluble fibrin, and fibrin-degradation product were significantly higher during normal pregnancy than at 6 weeks post partum. Plasmin-alpha2-antiplasmin complex levels did not change. No differences between the pre-eclamptic and normotensive pregnancy groups were found for any of the hemostatic markers. In group 2 normotensive women undergoing cesarean section, thrombin-antithrombin III complex and soluble fibrin levels were significantly higher in the uterine vein than in the antecubital vein. In group 2 women with pre-eclampsia, thrombin-antithrombin III complex and fibrin-degradation product levels were significantly higher in the uterine vein than in the antecubital vein. In addition, plasmin-alpha2-antiplasmin complex and fibrin-degradation product levels were higher and soluble fibrin levels were lower in the uterine vein in the pre-eclamptic group than in the normotensive group. CONCLUSION: Both the coagulation and fibrinolytic systems are activated during normal pregnancy. Activation of these systems is more marked in the uteroplacental circulation than in the systemic circulation in both normotensive and pre-eclamptic pregnancies. An abnormal pattern of hemostasis occurs in the uteroplacental circulation in pre-eclampsia.

Adult↗