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Kypros Nicolaides

Publications and source records attributed to Kypros Nicolaides.

15 recordsLinked to original sources
PubMed2025

Polygenic Risk Scores for Preeclampsia Prediction Beyond Gold-Standard Clinical Models in Multiethnic Populations.

BACKGROUND: Preeclampsia is a major cause of maternal and fetal mortality and morbidity. Early risk stratification enables timely preventative therapy in high-risk women. Polygenic risk scores (PGS) improve prediction in complex diseases, but their added value for preeclampsia remains unclear, particularly in comparison to gold-standard first-trimester prediction models and across non-European ancestries. METHODS: We evaluated the performance of both a preeclampsia and systolic blood pressure PGS in 2 prospective pregnancy cohorts with detailed phenotyping: the Fetal Medicine Foundation study (n=5207; 2127 cases) and the Pregnancy Outcome Prediction study (n=3659; 228 cases). Risk models included (1) clinical factors; (2) clinical factors plus PGS; (3) advanced model including first-trimester mean arterial pressure, PAPP-A (pregnancy-associated plasma protein-A), and uterine artery pulsatility index; and (4) advanced model plus PGS. Discriminative performance, measured by the area under the receiver operating characteristic curve, was assessed overall and by ancestry. RESULTS: The preeclampsia PGS was independently associated with preeclampsia (odds ratio per SD, 1.24 [95% CI, 1.17-1.31]; P<0.001). It modestly improved prediction over clinical models (area under the receiver operating characteristic curve 0.746 versus 0.750; P=0.017) but not over the advanced model (area under the receiver operating characteristic curve 0.817 versus 0.818; P=0.326). The systolic blood pressure PGS showed stronger performance, improving prediction over both models in women of European ancestry. No improvement was observed with either score in women of African ancestry. CONCLUSIONS: PGSs for preeclampsia and SBP provide modest added predictive value beyond clinical risk factors in European ancestry women. Limited utility in African ancestry women reflects underrepresentation in the genome-wide association studies used to develop current scores. As cohort sizes grow and models are refined, PGSs may become important tools for equitable risk stratification in maternal health.

Adult↗
PubMed2006

Outcome of antenatally diagnosed sacrococcygeal teratomas: single-center experience (1993-2004).

AIMS: Sacrococcygeal teratomas (SCTs) are the commonest neonatal tumors with an incidence of approximately 1:30,000. There are few large single-center series and even fewer describing both their antenatal and postnatal course. We report the outcome of all fetuses investigated at a tertiary fetal medicine center with this diagnosis. METHOD: Demographic details were obtained from a prospectively maintained database. Patient records were examined for additional data including antenatal and postnatal interventions. Data were described as median (range). RESULTS: Forty-one SCTs were diagnosed antenatally during the period 1993 to 2004. Twelve were excluded from subsequent analysis (single antenatal visit or attending for second opinion [n = 6] and termination of pregnancy [n = 6]). Twelve underwent fetal intervention (laser vessel ablation [n = 4], alcohol sclerosis [n = 3], cyst drainage [n = 2], amniodrainage [n = 2], vesicoamniotic shunt [n = 1]) for fetal hydrops and polyhydramnios to aid in delivery and to prevent obstructive uropathy developing in the fetus. Of these, 3 died in utero and 9 survived to be born (median gestational age, 33 weeks [27-37 weeks]). A further 3 died in the neonatal period. There are 6 long-term survivors (50%) from this group. Seventeen infants, without intervention, were born at median gestational age 38 weeks (26-40 weeks). One infant with severe cardiac anomalies died on the day of birth. All surviving infants had definitive excisional surgery at a median of 2 days (1-16 days). Current median follow-up of survivors is 39 months (8-86 months). There have been no recurrences. One child has mild constipation, and 3 are awaiting cosmetic revision of their scars. CONCLUSIONS: The overall survival of antenatally diagnosed SCT is approximately 77%, with the development of hydrops and others requiring in utero intervention carrying a poor prognosis. Otherwise, the outcome after surgical excision is excellent.

Adult↗
PubMed2006

Current consequences of prenatal diagnosis of congenital diaphragmatic hernia.

BACKGROUND: Today, the diagnosis of congenital diaphragmatic hernia (CDH) can readily be made in the prenatal period during screening ultrasound examination. Patients ought to be referred to rule out associated anomalies, and in isolated cases, prognosis is poor when the liver is intrathoracic and the lung-to-head ratio (LHR) is less than 1. In these patients, prenatal intervention aiming to reverse pulmonary hypoplasia can be considered. METHODS: We present our current algorithm for counselling patients presenting with CDH. Patients with a poor prognosis are offered percutaneous fetal endoluminal tracheal occlusion (FETO) with a balloon, inserted at 26 to 28 weeks. We report on the evolution of technique and results in a consecutive homogeneous case series and compare outcome in cases with similar severity managed in the postnatal period. RESULTS: Within a period of 28 months, FETO was performed between 26 and 28 weeks in 24 fetuses with severe left-sided CDH. Under general (n = 5), epidural (n = 17) or local (n = 2) anesthesia, the balloon was successfully positioned at first surgery (23/24) with a mean operation time of 20 minutes (range, 3-60 minutes). There were no serious maternal complications or direct fetal adverse effects. In the first 2 weeks after FETO, LHR increased from 0.7 to 1.7. Premature prelabour rupture of the membrane (PPROM) occurred in 16.7% and 33.3% at 28 and 32 weeks or earlier, respectively. Gestational age at delivery was 33.5 weeks. Patency of airways was restored either in the prenatal (n = 12) or perinatal period (n = 12). Early (7 days) and late (28 days) survival, and survival at discharge were 75% (18/24), 58.3% (14/24) and 50% (12/24), respectively. Half of nonsurvivors (n = 6) died of pulmonary hypoplasia and hypertension, in combination with PPROM and preterm delivery (n = 4) and balloon dislodgement (n = 2), which coincided with a short tracheal occlusion (TO) period (12 days). In the other 6, TO period was comparable to that in the 12 survivors (47 vs 42 days, respectively). In that group of 6 babies, only 2 died of pulmonary problems. Late neonatal survival (28 days) was higher with prenatal vs perinatal balloon retrieval 83.3% vs 33.3% (P = .013). In a multicentre study validating the criteria, survival till discharge in 37 comparable cases was 9% (3/32) and 13% (5/37) of parents opted for termination. CONCLUSION: Fetuses with isolated left-sided CDH, liver herniation, and LHR of less than 1 have a poor prognosis. Percutaneous FETO is minimally invasive and may improve the outcome in these highly selected cases. Airways can be restored before birth, allowing vaginal delivery and return to the referring tertiary unit and may improve survival rate. The procedure carries a risk for PPROM, although that may decrease with experience.

Decision Trees↗
PubMed2005

Optimized real-time quantitative PCR measurement of male fetal DNA in maternal plasma.

BACKGROUND: Circulating fetal DNA (cfDNA) in maternal plasma has been measured to investigate its possible relationship with pregnancy-related disorders, including fetal trisomy 21 and preeclampsia. The circulating concentrations of single-copy fetal genes, however, are close to the detection limits of PCR methods. METHODS: We optimized a protocol for the real-time quantitative PCR amplification of the multicopy sequence DYS14 on the Y-chromosome. This was compared with an established real-time PCR assay for the single-copy SRY gene. RESULTS: By probit regression analysis, the measurements of male DNA by the DYS14 assay had a 10-fold lower detection limit (0.4 genome equivalents) than did measurements of SRY. For plasma samples from women in the first trimester of pregnancy, imprecision (CV) was 2%-22% when amplifying DYS14 compared with 26%-140% for SRY. CONCLUSIONS: The low copy numbers of fetal DNA in plasma of women in the first trimester of pregnancy cannot be measured precisely when targeting single-copy sequences. Better results are obtained by amplifying a sequence that is present in multiple copies per male genome.

Chromosomes, Human, Y↗
PubMed2005

A link between high serum levels of human chorionic gonadotrophin and chorionic expression of its mature functional receptor (LHCGR) in Down's syndrome pregnancies.

Human chorionic gonadotrophin (hCG) is released from placental trophoblasts and is involved in establishing pregnancy by maintaining progesterone secretion from the corpus luteum. Serum hCG is detected in the maternal circulation within the first 2-3 wks of gestation and peaks at the end of the first trimester before declining. In Down's syndrome (DS) pregnancies, serum hCG remains significantly high compared to gestation age-matched uncompromised pregnancies. It has been proposed that increased serum hCG levels could be due to transcriptional hyper-activation of the CGB (hCG beta) gene, or an increased half life of glycosylated hCG hormone, or both. Another possibility is that serum hCG levels remain high due to reduced availability of the hormone's cognate receptor, LHCGR, leading to lack of hormone utilization. We have tested this hypothesis by quantifying the expression of the hCG beta (CGB) RNA, LHCGR RNA and LHCGR proteins in chorionic villous samples. We demonstrate that chorionic expression of hCG beta (CGB) mRNA directly correlates with high serum hCG levels. The steady-state synthesis of LHCGR mRNA (exons 1-5) in DS pregnancies was significantly higher than that of controls, but the expression of full-length LHCGR mRNA (exons 1-11) in DS was comparable to that of uncompromised pregnancies. However, the synthesis of high molecular weight mature LHCGR proteins was significantly reduced in DS compared to uncompromised pregnancies, suggesting a lack of utilization of circulating hCG in DS pregnancies.

Animals↗
PubMed2005

Definitive surgical management of antenatally diagnosed exomphalos.

BACKGROUND/PURPOSE: The management of exomphalos is controversial with many centers in the United Kingdom and elsewhere advocating a conservative nonsurgical approach for the larger examples. Nevertheless, this approach is not without problems or complication. The aim of the study was to ascertain the outcome of all infants with an antenatally diagnosed exomphalos treated recently at our institution using a policy of aggressive abdominal wall closure. METHODS: This is a retrospective review of all infants with exomphalos treated from January 1995 to September 2002. RESULTS: There were 35 infants, all of whom underwent surgery. These were separated into 3 groups: group A (all exomphalos minor) underwent primary closure (n = 11), group B (exomphalos major) underwent primary closure (n = 13), and group C (exomphalos major) underwent staged closure involving a silo (n = 11). Infants in group C had a lower birth weight (P = .05) and were less mature (P = .06). They required longer periods of ventilation (P < .001), a longer hospital stay (P = .001), and a longer period to achieve full enteral feeds (P < .001). Overall survival was 34 (97%) of 35 infants. One premature infant who was born with a ruptured exomphalos sac (birth weight, 862 g) died of nonsurgical complications (sepsis and respiratory failure) early after the creation of a silo. CONCLUSIONS: An aggressive surgical approach in infants with exomphalos is a safe option resulting in effective abdominal wall closure. This requires a skilled multidisciplinary approach and possibly greater resources than other options.

Abdominal Wall↗
PubMed2005

Fetal intervention for congenital diaphragmatic hernia: the European experience.

Fetuses with CDH presenting with liver herniation and a lung area-to-head circumference ratio of less than 1.0 have a high chance for neonatal death due to pulmonary hypoplasia. Fetal tracheal occlusion (TO) prevents egress of lung liquid, which triggers lung growth. In animal experiments, we were able to develop a minimally invasive technique for Fetoscopic Endoluminal Tracheal Occlusion (FETO) with a detachable balloon. In 2001, we demonstrated feasibility of FETO by percutaneous access in fetuses with severe CDH. In a retrospective multicenter review, we obtained LHR measurements and position of the liver in 134 cases of isolated left-sided CDH between 24 and 28 weeks. Eleven patients (8%) with LHR < 1.4 opted for termination. Overall survival of liveborn babies was 47% (58/123). LHR and position of the liver correlated both to survival. Combination of both variables predicted neonatal outcome better: liver up and LHR < 1.0 predicted a survival of 9%. When LHR < 0.6, there were no survivors irrespective of liver position. We could successfully perform endotracheal placement of the balloon in 20 cases at a median gestational age of 26 weeks. The mean duration of the operation was 22 (range 5-54) minutes. In 11 (55%) of these patients, there was postoperative prelabor (ie, <37 weeks) amniorrhexis. Membranes ruptured before 32 weeks in 35%, with a decreasing trend as experience increased. Ultrasound scans after FETO demonstrated an increase in the echogenicity of the lungs within 48 hours and improvement in the LHR from a median 0.7 (range 0.4-0.9) before FETO to 1.8 (range 1.1-2.9) within 2 weeks after surgery. The median gestation at delivery was 33.2 (range 27-38) weeks, and in 14 (70%) this occurred after 32 weeks. Surgical repair of the diaphragmatic hernia could be done in 13 babies, and in all but 1 the defect was extensive and required the insertion of a patch. Survival to discharge was 50%. These 10 long-term surviving babies are now aged 7 to 26 (median 19) months without known neurologic morbidity. Eight babies died in the neonatal period due to complications of the underlying disease. Two nonsurvivors died from other causes but with appropriately developed lungs. Improved survival coincided with increasing experience, in turn related to reduced incidence of postoperative amniorrhexis, later delivery, and a change in the policy on the timing of removal of the balloon from intrapartum to the prenatal period. Survival in eligible contemporary controls was 1/12 (8%). The presence of liver herniation and a low lung-to-head ratio (LHR <1.0) is a good predictor of poor prognosis at different tertiary centers around the world. Severe CDH may be successfully treated with FETO, which is minimally invasive and may improve postnatal survival.

Balloon Occlusion↗
PubMed2004

Placental expression of interferon-gamma (IFN-gamma) and its receptor IFN-gamma R2 fail to switch from early hypoxic to late normotensive development in preeclampsia.

The inability of the mother to switch from T helper cell type 1 (Th1) to Th2 cytokine profiles at the fetal-maternal interface has been proposed as one of the primary causes of miscarriage, intrauterine growth restriction (IUGR), and preeclampsia (PE). The Th1 [interferon-gamma (IFN-gamma), TNF-alpha, and IL-12] and Th2 (IL-4 and IL-10) cytokines have opposite effects on human pregnancy. Leukemia inhibitory factor (LIF) promotes embryo implantation and sustains pregnancy, whereas IFN-gamma and TNF-alpha are detrimental to pregnancy. Both IFN-gamma and LIF are produced by maternal cells and tissues at the fetal-maternal interface, whereas the IFN-gamma receptors (IFN-gamma R1 and IFN-gamma R2) and LIF receptor are abundantly expressed on the surface of placental trophoblasts. The effect of IFN-gamma on T lymphocyte activation is influenced by the relative membrane density of its two receptors, particularly IFN-gamma R2. In this study we report that in PE (25-40 wk gestation) and PE complicated by IUGR, IFN-gamma R2 protein expression is severely down-regulated and is similar to that observed in early placenta (7-10 wk gestation) developing under low O(2) tension. IFN-gamma production was found to be inversely related to the IFN-gamma R2 protein expression, and LIF receptor protein expression in PE mimicked that in early placental development. These results show that in PE, placental trophoblasts fail to establish an early to late switch with respect to IFN-gamma and IFN-gamma R2 expression. This supports the hypothesis that trophoblasts control the polarization of maternal immune effectors and cytokine profiles at the fetal-maternal interface that could be subject to oxidative stress in PE.

Base Sequence↗
PubMed2004

Respiratory function in pregnancy at sea level and at high altitude.

OBJECTIVE: To determine the effect of pregnancy on respiratory function in a non-Caucasian group and determine whether there was an interaction between pregnancy and altitude of residence. DESIGN: Prospective cross sectional study. SETTING: Antenatal clinics in Peru, at sea level in Lima and at high altitude in Cerro de Pasco. SAMPLE: Peruvian women with singleton pregnancies; 122 living at sea level and 192 living at 4300 m altitude in the Peruvian Andes. At each location, 19 non-pregnant women were also studied. METHODS: Respiratory function was measured in pregnant and non-pregnant women living at sea level and at 4300 m. MAIN OUTCOME MEASURES: Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEFR), total lung capacity (TLC), inspiratory capacity (IC), residual volume (RV), expiratory residual volume (ERV) and functional residual capacity (FRC). RESULTS: At sea level, RV and TLC were higher in the third compared with the first trimester (P < 0.05). At high altitude, FEV1 (P < 0.01), ERV (P < 0.01) and FRC (P < 0.01) were lower in the third compared with the first trimester. Pregnant and non-pregnant women at high altitude were 4 cm shorter (P < 0.0001) and had larger lung volumes (P < 0.01); their total lung capacities were approximately 1 L greater than women living at sea level (P < 0.0001). CONCLUSION: These results suggest that the effect of pregnancy on the respiratory function of healthy women is influenced by altitude of residence.

Altitude↗
PubMed2003

Temporal regulation of the expression of syncytin (HERV-W), maternally imprinted PEG10, and SGCE in human placenta.

Maternally imprinted PEG10 and SGCE, separated by approximately 2.15 Mb from Syncytin (HERV-W) gene at 7q21.3, are implicated in choriocarcinoma and Silver-Russell syndrome. Here we have analyzed the temporal regulation of mRNA expression of these genes in placenta and demonstrate that Syncytin gene activation is highest in term placenta, PEG10, downregulated at early hypoxic phase, and highly activated at 11-12 wk of gestation. In contrast, transcription from SGCE remained unchanged throughout pregnancy, suggesting two neighboring imprinted genes are differentially regulated at very early pregnancy. Additionally, accumulation of two major species of mRNA (8 kb and 3.1 kb) encoded by HERV-W in placenta is regulated: 3.1 kb mRNA level remained unchanged throughout pregnancy, whereas the production of 8 kb species was highest in term placenta. Western blot and immunohistochemical staining of placental tissues with monoclonal antibodies revealed a marked reduction of syncytin glycoprotein synthesis in late pregnancy. Therefore, the relative levels of 3.1 kb and 8 kb mRNAs in trophoblasts could regulate syncytin protein synthesis, possibly by competition of the two mRNA species for translational apparatus.

Apoptosis Regulatory Proteins↗
PubMed2003

Pulmonary diffusing capacity in pregnancy at sea level and at high altitude.

The impact of pregnancy on respiratory function and whether this is influenced by living conditions, such as altitude of residence, must be determined if the management of pregnant women, particularly those with pulmonary disease is to be optimized. Pulmonary diffusing capacity, corrected for haemoglobin concentration (DL(COc)), therefore, was measured in 112 healthy Peruvian women with singleton pregnancies living at sea level and 192 living at 4300 m. At each location, 19 non-pregnant women were studied. The mean DL(COc)s of the pregnant and non-pregnant women studied at sea level were similar but lower than those of their high altitude counterparts (P<0.001, P<0.001). At high altitude, the mean DL(COc)s of women studied in the first and second trimester were similar to that of non-pregnant women, but the mean DL(COc) of pregnant women studied in the third trimester was lower than that of the non-pregnant women (P<0.01). Our results demonstrate that the effect of pregnancy on pulmonary diffusing capacity is influenced by altitude of residence.

Altitude↗
PubMed2002

Cervical screening for preterm delivery.

The ability of sonographic cervical length screening to detect those at risk of spontaneous preterm delivery has been extensively explored over the past few years. This applies both to high-risk and low-risk groups. Cervical length measurement appears to be superior to biochemical, microbiological or hormonal methods of screening. The screening technique has been standardized, but the cervical length for intervention and the timing and nature of intervention have not been defined. Cervical cerclage appears to be of use to prevent or arrest the progress of cervical dilation in high-risk cases, but the management of the screen-positive low-risk case has yet to be determined. Future management may be stratified according to actual cervical length, and prospective randomized trials of treatment for the short cervix are needed.

Biomarkers↗
PubMed2002

Respiratory function in singleton and twin pregnancy.

OBJECTIVE: Singleton pregnancy causes important changes in respiratory function. The incidence of twin pregnancies is increasing, but it is not known whether affected women suffer greater respiratory compromise. The aim of this study was to determine if changes in respiratory function during pregnancy in healthy women were greater in those with a twin pregnancy compared with those with a singleton pregnancy. DESIGN: Cross sectional study. SETTING: London teaching hospital. POPULATION: Healthy pregnant women attending the antenatal clinic and ultrasound department. METHODS: A cross sectional study of respiratory function was performed in 68 women with twin pregnancies (17 examined in the first trimester, 35 second trimester, 16 third trimester) and 140 women with singleton pregnancies (28, 80, 40, respectively) and 22 non-pregnant women. Women were examined once between 7 and 40 weeks of gestation. Forced vital capacity, relaxed vital capacity, forced expiratory volume in 1 second (FEV1), peak flow, inspiratory capacity, functional residual capacity (FRC), expiratory reserve volume, pulmonary diffusing capacity and minute ventilation were measured. RESULTS: Both in twin and singleton pregnancies, the mean FRC and expiratory reserve ventilation of women studied in the third trimester and minute ventilation of women studied in each trimester differed significantly from that of the non-pregnant women. There were, however, no significant differences demonstrated in respiratory function between healthy women with twin as compared with singleton pregnancies. CONCLUSION: In healthy women, the extra demands of atwin compared with a singleton pregnancy do not compromise further the respiratory system.

Adult↗