Screening for pre-eclampsia early in pregnancy: performance of a multivariable model combining clinical characteristics and biochemical markers.

OBJECTIVE: To investigate the performance of a multivariable model combining a priori clinical characteristics and biomarkers to detect, early in pregnancy, women at higher risk of developing pre-eclampsia (PE). DESIGN: Nested case-control study. SETTING: University medical centre, Quebec, Canada (CHU de Québec). POPULATION: A total of 7929 pregnant women recruited between 10 and 18 weeks of gestation. In all, 350 developed hypertensive disorders of pregnancy (HDP)-of which 139 had PE, comprising 68 with severe PE and 47 with preterm PE-and were matched with two women with a normal pregnancy. METHODS: We selected a priori clinical characteristics and promising markers to create multivariable logistic regression models: body mass index (BMI), mean arterial pressure (MAP), placental growth factor, soluble Fms-like tyrosine kinase-1, pregnancy-associated plasma protein A and inhibin A. MAIN OUTCOME MEASURES: PE, severe PE, preterm PE, HDP. RESULTS: At false-positive rates of 5 and 10%, the estimated detection rates were between 15% (5-29%) and 32% (25-39%), and between 39% (19-59%) and 50% (34-66%), respectively. Considering the low prevalence of PE in this population, the positive predictive values were 7% (5-9%) to 10% (7-13%) for PE and 2% (1-4%) to 4% (3-6%) in the preterm and severe PE subgroups. The multivariable model yielded areas under the receiver operating characteristics curves (AUC) between 0.72 (0.61-0.81) and 0.78 (0.68-0.88). When only BMI and MAP were included in the model, the AUC were similar to those of the a priori model. CONCLUSIONS: In a population with a low prevalence of preterm PE, a multivariable risk algorithm using an a priori combination of clinical characteristics and biochemical markers did not reach a performance justifying clinical implementation as screening test early in pregnancy.

Association between first-trimester placental volume and birth weight.

OBJECTIVE: To estimate the correlation between first-trimester placental volume, birth weight, small-for-gestational-age (SGA), and preeclampsia. METHODS: A prospective study of women with singleton pregnancy at 11-13 weeks of gestation was conducted. First-trimester placental volume was measured using three-dimensional ultrasound and reported as multiple of median (MoM) for gestational age. Participants were followed until delivery where birth weight, placental weight, and occurrence of preeclampsia were collected. Non-parametric analyses were performed. RESULTS: We reached a complete follow-up for 543 eligible women. First-trimester placental volume was significantly correlated with birth weight (correlation coefficient: 0.18; p < 0.0001) and placental weight (cc: 0.22; p < 0.0001) adjusted for gestational age. First-trimester placental volume was smaller in women who delivered SGA neonates (median MoM: 0.79; interquartile range: 0.62-1.00; p < 0.001) and greater in women who delivered large-for-gestational-age neonates (median MoM: 1.13; 0.95-1.49; p < 0.001) when compared to women with neonates between the 10th and 90th percentile (median MoM: 1.00; 0.81-1.25). First-trimester placental volume was not associated with the risk of preeclampsia (cc: 0.01; p = 0.87). CONCLUSION: First-trimester placental volume is strongly associated with fetal and placental growth. However, we did not observe a correlation between placental volume and the risk of preeclampsia.

OS090. Performance of candidate clinical and biochemical markers in screening early in pregnancy to detect women at high risk to develop preeclampsia.

INTRODUCTION: The advent of early preventive measures, such as low-dose aspirin targeting women at high risk of preeclampsia (PE), emphasizes the need for better detection. Despite the emergence of promising biochemical markers linked to the pathophysiological processes, systematic reviews have shown that, until now, no single tests fulfill the criteria set by WHO for biomarkers to screen for a disease. However, recent literature reveals that by combining various clinical, biophysical and biochemical markers into multivariate algorithms, one can envisage to estimate the risk of PE with a performance that would reach clinical utility and cost-effectiveness, but this remains to be demonstrated in various environments and health care settings. OBJECTIVES: To investigate, in a prospective study, the clinical utility of candidate biomarkers and clinical data to detect, early in pregnancy, women at risk to develop PE and to propose a multivariate prediction algorithm combining clinical parameters to biochemical markers. METHODS: 7929 pregnant women prospectively recruited at the first prenatal visit, provided blood samples, clinical and sociodemographic information. 214 pregnant women developed hypertensive disorders of pregnancy (HDP) of which 88 had PE (1.2%), including 44 with severe PE (0.6%). A nested case-control study was performed including for each case of HDP two normal pregnancies matched for maternal age, gestational age at recruitment, ethnicity, parity, and smoking status. Based on the literature we selected the most promising markers in a multivariate logistic regression model: mean arterial pressure (MAP), BMI, placental growth factor (PlGF), soluble Flt-1, inhibin A and PAPP-A. Biomarker results measured between 10-18 weeks gestation were expressed as multiples of the median. Medians were determined for each gestational week. RESULTS: When combined with MAP at the time of blood sampling and BMI at the beginning of pregnancy, the four biochemical markers discriminate normal pregnancies from those with HDP. At a 5% false positive rate, 37% of the affected pregnancies would have been detected. However, considering the prevalence of HDP in our population, the positive predictive value would have been only 15%. If all the predicted positive women would have been proposed a preventive intervention, only one out 6.7 women could have potentially benefited. In the case of severe PE, performance was not improved, sensitivity was the same, but the positive predictive value decreased to 3% (lower prevalence of severe PE). CONCLUSION: In our low-risk Caucasian population, neither individual candidate markers nor multivariate risk algorithm using an a priori combination of selected markers reached a performance justifying implementation. This also emphasizes the necessity to take into consideration characteristics of the population and environment influencing prevalence before promoting wide implementation of such screening strategies. In a perspective of personalized medicine, it appears more than ever mandatory to tailor recommendations for HDP screening according not only to individual but also to population characteristics.

PP054. Predicting preeclampsia at late mid-term pregnancy before occurrence of clinical symptoms: Clinical utility of biomarkers and clinical parameters in a low-risk population.

INTRODUCTION: Despite research efforts and healthcare improvement, preeclampsia (PE) continues to be a leading cause of maternal and fetal morbidity and mortality. Early identification of women at risk of developing PE is the most promising approach to implement preventive measures such as low-dose aspirin to reduce negative outcomes. However, it is still relevant to evaluate pregnant women to detect PE before the occurrence of clinical symptoms and/or to have better tools to assist in its differential diagnosis. Recently, measurements of biomarkers such as soluble fms-like tyrosine kinase-1 (SFLT-1) and placental growth factor (PlGF) have been proposed and some manufacturers are already marketing reagents for this purpose. OBJECTIVES: To examine in a prospective study the performance of selected clinical and biochemical markers for identifying late mid-term pregnancy women at risk of developing PE within a few weeks. METHODS: Seven thousand nine hundred and twenty nine pregnant women prospectively recruited at the first routine prenatal visit, provided blood samples, clinical and sociodemographic information. Two hundred and fourteen pregnant women developed hypertensive disorders of pregnancy (HDP) of which 88 had PE (1.2%), including 44 who presented with severe PE (0.6%). We performed a nested case-control study from the whole cohort including for each case of HDP two normal pregnancies after matching for maternal age, gestational age at recruitment, ethnicity, parity, and smoking status. Based on the literature, we selected the most promising clinical and biochemical markers to be included in a multivariate logistic regression model: mean arterial pressure and body mass index (BMI), PlGF, SFLT-1, inhibin A, and PAPP-A. All markers were measured between 20 and 32 weeks of gestation except for BMI (early pregnancy). All biological marker results were transformed in multiples of median. Medians were established for each gestational week. Multivariate logistic regression analyses were performed to develop prediction algorithm. RESULTS: The resulting regression model discriminated the affected from normal pregnancies as indicated by an area under the receiver operating characteristics (ROC) curve of 0.8. But at a 5% false positive rate, only 28% of the women who have developed HDP would have been detected. Even when the statistical analyses were limited to severe PE, the performance was poor: sensitivity 30%, positive predictive value 2.7%. CONCLUSION: In our low-risk Caucasian population, neither individual candidate markers nor multivariate risk algorithm using an a priori combination of selected clinical and biochemical markers reached a performance justifying implementation as a screening procedure. These results emphasize the necessity to take into consideration the environment, population and health care settings influencing prevalence and characteristics of HDP before promoting wide implementation of such screening strategies. It is imperative to tailor future recommendations for HDP screening not only according to the individual but also to the population characteristics if clinical utility has to be reached.

Alteration of calcium homeostasis in primary preeclamptic syncytiotrophoblasts: effect on calcium exchange in placenta.

Preeclampsia (PE) is characterized by maternal hypertension, proteinuria, oedema and, in 30% of cases, by intrauterine growth retardation. Causes are still unknown; however, epidemiological and clinical studies have suggested alterations in maternal calcium metabolism. We suggested that in PE, calcium transport by the syncytiotrophoblast (ST) is disturbed. From total placental tissues, we studied the expression of: calcium channels (TRPV5, TRPV6 [transient receptor potential vanilloid]), calcium binding proteins (CaBP-9K, CaBP-28K), plasma membrane calcium ATPase (PMCA)1,2,3,4 pumps, ATP synthase, genes implicated in Ca(2+) release [inositol-1,4,5-triphosphate receptor (IP3R)1,2,3; Ryanodine receptor (RyR)1,2,3] and replenishment (SERCA1,2,3 [sarcoendoplasmic reticulum Ca(2+) ATPases]) from endoplasmic reticulum, channels implicated in mitochondrial Ca(2+) accumulation (VDAC1,2,3 [voltage-dependent anion channels]) and a marker of oxidative stress (hOGG1 [Human 8-oxoguanine-DNA glycosylase 1]), as well as the influence of these variations on calcium transport in primary ST cultures. The mRNA and protein levels were thereby examined by real-time PCR and Western blot analysis, respectively, in two different groups of pregnant women with similar gestational age: a normal group (n= 16) and a PE group (n= 8), diagnosed by a clinician. Our study showed a significant decrease in calcium transport by the ST cultured from preeclamptic placentas. We found a significant (P < 0.05) decrease in mRNA levels of TRPV5, TRPV6, CaBP-9K, CaBP-28K, PMCA1, PMCA4, ATP synthase, IP3R1, IP3R2, RyR1, RyR2 and RyR3 in PE group compared to normal one. We also noted a significant decrease in protein levels of TRPV5, TRPV6, CaBP-9K, CaBP-28K and PMCA1/4 in PE group. In contrast, SERCA1, SERCA2, SERCA3, VDAC3 and hOGG1 mRNA expressions were significantly increased in PE placentas. Calcium homeostasis and transport through placenta is compromised in preeclamptic pregnancies and it appears to be affected by a lack of ATP and an excess of oxidative stress.

Modulation of placental protein expression of OLR1: implication in pregnancy-related disorders or pathologies.

The lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (OLR1) is a newly described receptor for oxidatively modified LDL. The human pregnancy is associated with hyperlipidemia and oxidative stress. It has been reported that modification in maternal lipid profile can induce disturbance during pregnancy. In this study, we have evaluated the expression protein level of OLR1 in human term placenta of women having plasma cholesterol level lower to 7 mM or higher to 8 mM and women of gestational diabetes mellitus (GDM) by western blot analysis. The present study demonstrates that the maternal lipid profile is associated with placental protein expression of OLR1. A significant increase in the protein expression of OLR1 was observed in placenta of women with elevated plasmatic total cholesterol level (>8 mM). In addition, the placental protein expression of OLR1 is increased in mothers having the highest pre-pregnancy body mass index (BMI) and low (<7 mM) plasmatic total cholesterol level at term. Interestingly, the placental protein expression of OLR1 is increased in the presence of GDM pregnancies compared with normal lipids level pregnancies, without the modification of mRNA expression. In conclusion, placental OLR1 protein expression is associated with maternal lipid profile, pre-pregnancy BMI, and pathology of GDM.

Influence of maternal lipid profile on placental protein expression of LDLr and SR-BI.

Maternal hyperlipidemia is a characteristic feature during pregnancy, it has been reported that modification of the maternal lipid profile can induce disturbance during pregnancy. In this study, we evaluated the impact of maternal lipid profile on the placental protein expression of two major receptors in cholesterol metabolism, the low density lipoprotein receptor (LDLr) and the scavenger receptor type B1 (SR-B1). We demonstrate an increase in the level of maternal total circulating cholesterol leads to a significant decrease in the level of the LDLr protein expression, while the level of the SR-BI expression remains unchanged. A similar change, for LDLr, is observed in association with the maternal pre-pregnancy body mass index and weight gain. Our data suggest that the LDLr plays a role in regulating cholesterol delivered to the baby from the placenta.

Quantification of all fetal nucleated cells in maternal blood in different cases of aneuploidies.

We quantified all fetal nucleated cells (FNCs) per unit volume of maternal blood in different aneuploid pregnancies using molecular cytogenetic techniques. Seven cases of male trisomy 18, two triploidies (69,XXX), two 47,XXX, one 47,XXY, one 47,XYY, one male trisomy 13, and one case of 47,XY,r(22),+r(22) were analyzed. Whole blood samples were obtained from 15 women between 17 and 29 gestational weeks and harvested without using fetal cell enrichment procedures. Fluorescence in situ hybridization and primed in situ labeling were performed to identify the FNCs. All slides were manually scanned to quantify those cells. We have identified 4-20 FNCs/ml of maternal blood in the cases of trisomy 18; 10 and 25 FNCs/ml in the two cases of triploidy; 16 and 14 FNCs/ml, respectively, in the two X trisomies; 19 FNCs/ml in the 47,XXY; 26 FNCs/ml in the 47,XYY; nine FNCs/ml in the trisomy 13; and 10 FNCs/ml in the case of r(22). To detect all FNCs in all aneuploid pregnancies, we have used a very simple method that minimizes the manipulation steps to avoid losing fetal cells. The number of FNCs identified in aneuploid pregnancies was 2-5 times higher than in normal pregnancies. This higher number of FNCs will favor the design of a non-invasive pre-natal test.

Rosiglitazone and ethinyl estradiol/cyproterone acetate as single and combined treatment of overweight women with polycystic ovary syndrome and insulin resistance.

BACKGROUND: Few studies have evaluated insulin sensitizers in comparison/association with oral contraceptives (OC) in women with polycystic ovary syndrome (PCOS) with insulin resistance (IR). This study assessed the effects of a thiazolidinedione versus an anti-androgenic estrogen-progestin followed by their sequential combinations in overweight PCOS women. METHODS AND RESULTS: Twenty-eight candidates in whom elevated insulin was not normalized after 4 months of diet were randomly assigned to 6 months of rosiglitazone 4 mg/day or to ethinyl estradiol 35 mg/cyproterone acetate 2 mg (EE/CPA: 21/28 days cycle). Each group then received both medications for another 6 months. Rosiglitazone reduced insulin, IR indices [homeostasis model assessment (HOMA) and quantitative sensitivity check index (QUICKI)] and the insulin area under the curve in response to an oral glucose tolerance test (OGTT), but had limited effect on lipids, androgens and hirsutism. EE/CPA did not modify insulin and OGTT response but increased high-density lipoprotein cholesterol and triglycerides and decreased androgens and hirsutism. Similar changes occurred during combined treatments. End results were highly significant in combined groups without noticeable side-effects or changes in safety parameters. CONCLUSIONS: In obese PCOS women with high insulin not corrected by diet, the combination of rosiglitazone and EE/CPA may be used to achieve complementary beneficial effects on endocrine-metabolic anomalies and clinical symptoms.

Standardization in laboratory medicine: new challenges.

The primary goal of Laboratory Medicine is to provide information that is useful to assist medical decision-making and permits optimal health care. This type of information should be independently obtained of the measurement test kits and instruments, and also of the laboratory where the procedure is carried out. It is therefore important to achieve a level of comparability of laboratory results among the many measurement procedures available so that results are harmonized and interchangeable over space and time. The standardization of measurements is therefore of high priority. In recent years, numerous efforts have been made at the international level under the auspices of the IFCC and other organizations to standardize measurement results for many important analytes, e.g. enzymes, cardiac proteins, etc. The aim of this review is to discuss some concepts related to the achievement of standardization by the implementation of a metrologically correct measurement system, providing some examples on how these concepts can be applied in Laboratory Medicine.

The effects of flaxseed dietary supplement on lipid profile, bone mineral density, and symptoms in menopausal women: a randomized, double-blind, wheat germ placebo-controlled clinical trial.

Phytoestrogens are increasingly incorporated into the diet of menopausal women. However, there are limited data on the efficacy of flaxseed on the consequences of estrogen deficiency in menopausal women. The purpose of the study was to assess the effects of flaxseed incorporation into the diet of healthy menopausal women. One hundred and ninety-nine menopausal women were randomly assigned to consume 40 g flaxseed/d (n = 101) or wheat germ placebo (n = 98) for 12 months. At baseline and at month 12, serum levels of lipids, bone mineral density (BMD), and menopausal symptoms were evaluated. Statistical analysis was performed under the intention to treat principle. Flaxseed reduced serum total (-0.20 +/- 0.51 mmol/liter; P = 0.012) and high-density lipoprotein (-0.08 +/- 0.24 mmol/liter; P = 0.031) cholesterol concentrations compared with wheat germ placebo. BMD did not differ significantly between the two arms. Both flaxseed and wheat germ reduced (P < 0.0001) the severity scores of menopausal symptoms, but no statistical difference was found between the two arms. Our findings suggest that 1-yr incorporation of flaxseed into the diet produced a favorable, but not clinically significant, effect on blood cholesterol and caused no significant change in BMD or symptoms in healthy menopausal women.

Estrogen/progesterone replacement versus pravastatin and their sequential association in hypercholesterolemic postmenopausal women.

OBJECTIVES: The objectives of this study were to assess serum lipid changes in response to an oral estrogen combined with progesterone (Group A) as compared with pravastatin (Group B) and to evaluate the additive effects of the sequential addition of statin to hormonal replacement therapy (HRT) and of HRT to statin. METHODS: Thirty-seven of 63 hypercholesterolemic menopausal women initially submitted to a 4-month diet were randomised to oral conjugated estrogens (0.625 mg)/micronised progesterone (200 mg) or to pravastatin (40 mg). After 6 months, each group received both medications for another 6 months. RESULTS: Nineteen percent of women corrected their lipids below decision levels with diet alone. Low density lipoprotein-cholesterol (LDL-C) decreased by 8+/-5% with HRT and by 26+/-3% (P<0.001) with the statin. These single medications increased high density lipoprotein-cholesterol (HDL-C) by 13+/-5% (P<0.01) and 11+/-7%, respectively. Combined interventions produced cumulative LDL-C reductions of 40+/-2 and 42+/-3% (P<0.001) and additive HDL-C augmentations of 16+/-4 and 23+/-5% (P<0.01) with proportional changes in apolipoprotein (Apo)B-100 and ApoA-1. These combined effects brought the atherogenic index (C/HDL-C) for Groups A and B, respectively, from a moderate (5.18+/-0.25 and 5.87+/-0.18) to a reduced (3.35+/-0.20 and 3.52+/-0.19) risk category. Triglycerides (TG) which were increased by HRT and decreased by the statin returned to baseline during combined treatments. No changes in diet, physical activity or anthropomorphometric measurements explained the lipid modifications. CONCLUSIONS: In menopausal patients with elevated C not responding to diet, pravastatin was most effective to decrease LDL-C, and oral estrogen-micronised progesterone most effective to increase HDL-C. Marked reduction of the atherogenic index is achieved by sequential combinations of medications resulting from beneficial cumulative effects on both C-LDL and C-HDL.

Quantification of all fetal nucleated cells in maternal blood between the 18th and 22nd weeks of pregnancy using molecular cytogenetic techniques.

Different types of nucleated fetal cells (trophoblasts, erythroblasts, lymphocytes, and granulocytes) have been recovered in maternal peripheral blood. In spite of many attempts to estimate the number of fetal cells in maternal circulation, there is still much controversy concerning this aspect. The numbers obtained vary widely, ranging from 1 nucleated cell per 104 to 1 per 109 nucleated maternal cells. The purpose of our project was to determine the absolute number of all different types of male fetal nucleated cells per unit volume of peripheral maternal blood. Peripheral blood samples were obtained from 12 normal pregnant women known to carry a male fetus between 18 and 22 weeks of pregnancy. Three milliliters (3 ml) of maternal blood has been processed without any enrichment procedures. Fluorescence in situ hybridization (FISH) and primed in situ labeling (PRINS) were performed, and fetal XY cells were identified (among maternal XX cells) and scored by fluorescent microscopy screening. The total number of male fetal nucleated cells per milliliter of maternal blood was consistent in each woman studied and varied from 2 to 6 cells per milliliter within the group of normal pregnancies. The number of fetal cells in maternal blood, at a given period, is reproducible and can therefore be assessed by cytogenetic methods. This confirms the possibility of developing a non-invasive prenatal diagnosis test for aneuploidies. Furthermore, we demonstrate that it is possible to repeatedly identify an extremely small number of fetal cells among millions of maternal cells.

Optimization of the fluorescence in situ hybridization (FISH) technique for high detection efficiency of very small proportions of target interphase nuclei.

Using commercially available fluorochrome-labeled probes specific for chromosomes X, Y, 13, 18, and 21, we optimized the technical protocols for fluorescence in situ hybridization (FISH) so that the highest sensitivity and specificity were achieved. Also, we compared the optical properties of different types of fluorescent labels in an effort to develop the most efficient FISH protocol, including the determination of which types of labels are the easiest to count accurately. The lymphocytes were purified from blood of normal male and female newborns, normal male and female adults, and a trisomy 21 male adult. Male and female lymphocytes were mixed in five different combinations. For each combination, the male lymphocytes either from newborns or from adults were diluted with female lymphocytes in seven different proportions. For each of these 35 different cell mixtures, 100,000 nuclei were analyzed and scored in a blind fashion. Among the different fluorochrome-labeled probes, the highest sensitivity and specificity were achieved when SpectrumAqua CEP-Y/SpectrumOrange CEP X probe mixture, SpectrumAqua CEP-18, SpectrumOrange LSI-13, and SpectrumOrange LSI-21 were hybridized. The hybridization sensitivity and specificity were higher than 99% for the identification of chromosomes X, Y, 13, and 18, and higher than 98% for the detection of trisomy 21. The proportion of false-positive signals was under 0.005% for XY detection and lower than 0.14% for autosome detection. With these high hybridization sensitivities and specificities, the optimized FISH protocol developed in our laboratory has the potential to detect very rare events, e.g., when the proportion of cells being sought is lower than 0.01%. In other words, our protocol allows the specific detection of one male cell sunken among 10,000 female cells.

Multicenter evaluation of the Glucometer Elite XL meter, an instrument specifically designed for use with neonates.

OBJECTIVE: To evaluate the clinical performance of the Glucometer Elite XL Diabetes Care System in neonatal settings using a multicenter study RESEARCH DESIGN AND METHODS: A total of 388 blood specimens from 333 neonates were included in the study. A capillary or arterial sample was analyzed for determination of glucose with the Glucometer Elite XL system by an attending trained nurse. Through the same sampling site, a specimen was collected and sent to the laboratory for measurement of plasma glucose, bilirubin, and hematocrit. RESULTS: The regression analysis between the results of the Glucometer Elite XL system and comparative methods resulted in the following: Glucometer Elite XL meter = 1.01 x laboratory method + 0.02 mmol/l (n = 388). For the 1.1-4.0 mmol/l plasma glucose range, the regression was Glucometer Elite XL meter = 1.07 x laboratory method + 0.12 mmol/l (n = 150). A difference plot indicated a mean bias of 0.04 mmol/l (95% CI -0.01 to 0.10). No relationship was found between meter glucose biases and hematocrit levels (r = 0.10, P = 0.14). Although a statistically significant correlation existed between bilirubin levels and the glucose meter biases (r = 0.14, P = 0.005), the predicted mean biases were of little clinical significance. CONCLUSIONS: The Glucometer Elite XL system showed a good performance when used in neonatal settings.

Impact of a cholesterol enriched diet on maternal and fetal plasma lipids and fetal deposition in pregnant rabbits.

Pregnancy is associated with a hypercholesterolemic and a hyperlipidemic state. The totality of the essential fatty acids and 50% of the lipids needed by the fetus are transferred by the placenta from the maternal circulation. The hypothesis of this study is that an augmentation of the maternal plasmatic cholesterol is modifying the fetal lipids accumulation and development during rabbit pregnancy. To demonstrate the impact of a cholesterol enriched diet on plasma lipids during rabbit's pregnancy and on their fetus, we have established two groups: control and hypercholesterolemic rabbits (fed with a 0.2% cholesterol diet). Blood samples were collected before mating and at each trimester of pregnancy for analysis of lipid fractions and their lipoproteins. Plasma analysis shows that starting the 10th day of pregnancy the concentration of total-cholesterol and lipoproteins decreases for both groups. We have demonstrated that for the hypercholesterolemic group, concentrations of total-cholesterol (631%) and lipoproteins are significantly higher at the end of pregnancy than those for the control group. For both groups, after 20 days of pregnancy, triglycerides metabolism was biphasic showing a significant increase followed by a diminution in their concentration. In both groups, free fatty acids increases significantly at the end of the pregnancy (537.5% for the control group and 462.5% for the hypercholesterolemic group). Furthermore, the offsprings of hypercholesterolemic dams manifest a lower birth weight (15.5%) than those of control group. Our results demonstrate that a cholesterol enriched diet modifies greatly the fetal development and lipid metabolism during rabbit's pregnancy. These modifications could be useful for the understanding of the interaction between diet and fetal development in rabbit and probably during human pregnancy.

A prospective longitudinal study of platelet angiotensin II receptors for the prediction of preeclampsia.

OBJECTIVES: We developed a simplified method using a relatively small volume of blood for the determination of platelet angiotensin II receptors by saturation analysis and we evaluated its performance for the prediction of preeclampsia. DESIGN AND METHODS: A platelet suspension with minimal contamination by leukocytes and erythrocytes is obtained by centrifugation and washing. The platelet concentrate is incubated in a multi-well plate with increasing concentration of radiolabelled angiotensin II in the presence or absence of an excess of unlabelled angiotensin II. Bound and free fractions are separated using an oil mixture. Maximum binding is determined by Scatchard plot. This method was compared with a previously reported method. Our method was prospectively evaluated in 801 women attending our institution for routine prenatal care. A specimen was obtained at each trimester of pregnancy whenever possible. Diagnosis of preeclampsia was done postnatally by an experienced obstetrician. RESULTS: The method showed acceptable correlation with a previously published method although a proportional bias of 2.1 was observed between the two methods. No differences in mean maximum binding were observed between normal and affected pregnancies at either trimester. Even when the results were analyzed longitudinally, using the change in maximum binding between two trimesters for each patient, no significant increase could be documented in preeclamptic pregnancies. CONCLUSIONS: Platelet angiotensin II receptor measurement is not a clinically useful marker for the prediction of preeclampsia.

Prediction of pre-eclampsia, low birthweight for gestation and prematurity by uterine artery blood flow velocity waveforms analysis in low risk nulliparous women.

OBJECTIVE: To assess the performance of four previously reported Doppler abnormalities of uterine artery velocity waveforms (presence of a protodiastolic notch, peak systolic over protodiastolic velocities (A:C ratio) > 2.5, peak systolic over end diastolic velocities (A:B ratio) > 90th centile, resistance index (RI) ([A-B]/A) > or = 0.58) in predicting pre-eclampsia, low birthweight and prematurity. DESIGN: Prospective cohort study. SETTING: Tertiary care university hospital in Quebec City. POPULATION: 1311 nulliparous women. METHODS: Evaluation of pulsed Doppler abnormalities of uterine artery velocity waveforms was carried out in 1000 and 1194 of women at 18.3 (SD 0.9) or 26.7 (SD 0.9) weeks of pregnancy. MAIN OUTCOME MEASURES: Pre-eclampsia, birthweight below the 10th centile for gestational age and spontaneous preterm birth (< 37 completed gestation weeks). RESULTS: Pre-eclampsia, low birthweight for gestation and prematurity occurred in 4%, 11% and 7% of the pregnancies, respectively. At 26 weeks all the abnormalities of the studied Doppler indices were significantly associated with pre-eclampsia and low birthweight for gestation as reflected by the 95% confidence intervals of the positive likelihood ratios which did not include the value 1. However, sensitivities (26% to 34%) and positive predictive values (7% to 28%) were low. No Doppler indices performed significantly better than the others. The abnormalities of the Doppler indices were not associated with spontaneous prematurity. The performance of the Doppler measurements performed at 18 weeks was poor. CONCLUSIONS: Uterine artery Doppler velocimetry waveform analysis does not qualify as a reliable screening test for pre-eclampsia or low birthweight for gestation in low risk pregnancies but may be useful in selected high risk populations.

Evaluation of the analytical performance of the Boehringer Mannheim Elecsys 2010 immunoanalyzer.

OBJECTIVES: We evaluated the analytical performance of the Elecsys 2010 immunoanalyzer (Boehringer Mannheim Canada), which is based on a new detection technology, electrochemical luminescence. DESIGN AND METHODS: We used six representative assays from the initial launch menu of the instrument: thyroid stimulating hormone (TSH), free thyroxine (FT4), troponin T, human chorionic gonadotropin (hCG), carcinoembryonic antigen (CEA), and prostate specific antigen (PSA). Within-run and between-day imprecision were evaluated using pools of human specimens at low, mid and high concentrations. Linearity was evaluated by diluting specimens with high analyte concentrations with specimens that had a low level of this analyte. Carry over and hook effect were investigated using specimens with high concentrations of hCG. Functional sensitivity was studied by running low TSH specimens over 21 daily runs, and by comparing the scatterplot of FT4 as a function of TSH. Over 100 specimens distributed across the analytical range were analyzed with two comparison methods: ES 300 (Boehringer Mannheim Canada) and AxSYM (Abbott Laboratories). RESULTS: Within-run and between-day imprecisions were less than 4% and 10%, respectively, for most assays. All assays were linear over the whole analytical range. Carry over was minimal (< 0.0002%). A hook effect was present for hCG levels greater than 560,000 U/L. The functional sensitivity of the TSH assay was lower than 0.02 mlU/L. Correlation coefficients were all > 0.94. Small proportional errors were observed in comparison studies for the CEA and PSA assays. CONCLUSIONS: The Elecsys 2010 system was shown to have an acceptable analytical performance for the rapid analysis of a wide variety of analytes. The hook effect observed with hCG assay would imply that the laboratory informs the clinicians of the possibility of falsely low values in trophoblastic diseases or that all specimens with values greater than 3000 U/L are reassayed after dilution.

Platelet angiotensin II binding sites and early detection of preeclampsia.

OBJECTIVE: To determine if platelet angiotensin II binding density during the second or third trimester of pregnancy can be used as a marker for early detection of women who will develop preeclampsia. METHODS: We collected blood samples from 412 nulliparous pregnant women during their second or third trimesters. They were classified in four groups after delivery: normotensive (n=297), transient hypertensive (n=54), preeclamptic (n=39), and chronic hypertensive (n=22). We also studied 35 nonpregnant women and 122 women in the peripartum period. The binding capacity of platelet angiotensin II receptors was analyzed in each patient. RESULTS: In normotensive pregnancies, there was a significant decrease in mean (+/-standard error of the mean [SEM]) platelet binding in the second trimester (1.6+/-0.2 fmol/10(9) cells) compared with nonpregnant women (3.3+/-0.7 fmol/10[9] cells). No statistical differences were observed in the mean (+/-SEM) number of platelet angiotensin II binding sites between the groups studied in the third trimester (normal: 1.7+/-0.1 fmol/10(9) cells; transient hypertensive: 2.3+/-0.4 fmol/10(9) cells; preeclamptic: 1.6+/-0.4 fmol/10(9) cells, and chronic hypertensive: 1.6+/-0.6 fmol/10(9) cells), nor were any significant differences found in second-trimester values. At cutoff levels providing identical sensitivities, angiotensin II binding showed significantly lower positive predictive values than mean arterial pressure (P < .05). With this study's sample size, we could have demonstrated an improvement in positive predictive values of 20% with a statistical power (1-beta) of 90%. CONCLUSION: The measurement of platelet angiotensin II receptor density cannot be recommended for the early detection of preeclampsia.