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Kevin Spencer - One of the best experts on this subject based on the ideXlab platform.
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first trimester Screening for trisomy 21 by free beta human chorionic gonadotropin and pregnancy associated plasma protein a impact of maternal and pregnancy characteristics
Ultrasound in Obstetrics & Gynecology, 2008Co-Authors: Kevin Spencer, Karl Oliver Kagan, David Wright, Francisca S Molina, K H NicolaidesAbstract:Objectives To use multiple regression analysis to define the contribution of maternal variables that influence the measured concentration of free beta-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A), and the interaction between these covariates, in first-trimester Biochemical Screening for trisomy 21. Methods This was a multicenter study of prospective Screening for trisomy 21 by a combination of fetal nuchal translucency thickness, and maternal serum free β-hCG and PAPP-A at 11 + 0t o 13 + 6 weeks of gestation. In the pregnancies subsequently found to have trisomy 21 and in those with no obvious chromosomal abnormality, we used multiple regression analysis to account for pregnancy characteristics that influence the measured concentrations of free β-hCG and PAPP-A. We fitted Gaussian distributions to the distribution of log multiples of the median (MoM) values in trisomy 21 and in unaffected pregnancies. Results There were 491 cases of trisomy 21 and 96 803 chromosomally normal pregnancies. Compared with values in Caucasian women, those who were parous, non-smokers and those who conceived spontaneously, PAPP-A was 57% higher in women of Afro-Caribbean origin, 3% higher in South Asians, 9% higher in East Asians, 2% higher in nulliparous women, 17% lower in smokers and 10% lower in those conceiving by in-vitro fertilization (IVF). Free β-hCG was 12% higher in women of Afro-Caribbean origin, 9% lower in South Asians, 8% higher in East Asians, 2% higher in nulliparous women, 4% lower in smokers and 9% higher in those conceiving by IVF. In Screening for trisomy 21 by maternal age and serum free β-hCG and PAPP-A the estimated detection rate was 65% for a false-positive rate of 5%. Conclusions In first-trimester Biochemical Screening for trisomy 21 it is essential to adjust the measured values of free β-hCG and PAPP-A for maternal and pregnancy characteristics. Copyright 2008 ISUOG. Published by John Wiley & Sons, Ltd.
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the use of nuchal translucency measurement and second trimester Biochemical markers in Screening for down s syndrome
British Journal of Obstetrics and Gynaecology, 2001Co-Authors: G D Michailidis, Kevin Spencer, Demetrios L. EconomidesAbstract:Objective To assess the effectiveness of antenatal Screening for trisomy 21 by first trimester sonography followed by second trimester Biochemical Screening. Design Retrospective five-year review. Setting Maternity unit of a university hospital. Population An unselected group of 7447 pregnant women who had a first trimester scan and nuchal translucency measurement in our unit after January 1995 and had an estimated date of delivery before 1 January 2000. 11.9% were ≥ 37 years old. A subgroup (n=4864) also had second trimester Biochemical testing by alpha-fetoprotein and free β-human chorionic gonadotrophin. Main outcome measures Prenatal and postnatal diagnosis of trisomy 21. Results There were 23 fetuses affected with trisomy 21. The overall prenatal detection rate was 87% (20/23; 95% CI 66% to 97%) and we performed invasive procedures in 8.5% of our population. First trimester sonography identified 74% (95% CI 51.6% to 89.8%) of affected fetuses. Second trimester Biochemical Screening detected half of the fetuses with trisomy 21 which were missed by first trimester Screening, increasing the sensitivity to 90.5% (19/21; 95% CI 69.6% to 98.8%) for an invasive procedure rate of 4.2% performed in screened positive women. However, the positive predictive value of the Biochemical test was very low (0.5%). In screen negative women, karyotyping for advanced maternal age did not detect any affected fetuses. Conclusion First trimester nuchal translucency measurement is an effective Screening test for the prenatal detection of fetuses with Down's Syndrome. Although the measurement of Biochemical markers in the second trimester can detect additional affected fetuses this may be outweighed by the delay in diagnosis, the extra visits and cost so that the right time for Biochemical Screening is most likely to be in the first trimester.
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first trimester Biochemical Screening for trisomy 21 the role of free beta hcg alpha fetoprotein and pregnancy associated plasma protein a
Annals of Clinical Biochemistry, 1994Co-Authors: Kevin Spencer, Jennifer A Crossley, D A Aitken, G Mccaw, E Berry, R W Anderson, J M ConnorAbstract:The potential efficacy of Screening for trisomy 21 in the first trimester, using maternal serum markers alpha fetoprotein, free beta human chorionic gonadotropin, unconjugated oestriol and pregnancy associated plasma protein A, was studied in an unselected population of women between the seventh and fourteenth week of gestation. Using a combination of alpha fetoprotein and free beta human chorionic gonadotropin, 53% of affected pregnancies could be identified at a false positive rate of 5%. Unconjugated oestriol and pregnancy associated plasma protein A levels were lower in cases of trisomy 21, but their inclusion with other markers did not significantly improve detection rate. Monitoring the same pregnancies also in the second trimester showed that Screening in the first trimester identified the same cases as in the second. We conclude that first trimester Screening using free beta human chorionic gonadotropin and alpha fetoprotein, is a viable possibility and will lead to detection rates in excess of 50%. Prospective studies are needed to confirm these observations.
Rajesh V Thakker - One of the best experts on this subject based on the ideXlab platform.
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multiple endocrine neoplasia type 1
Endocrine-related Cancer, 1999Co-Authors: Anna A J Pannett, Rajesh V ThakkerAbstract:Combined clinical and laboratory investigations of multiple endocrine neoplasia type 1 (MEN1) have resulted in an increased understanding of this disorder which may be inherited as an autosomal dominant condition. Defining the features of each disease manifestation in MEN1 has improved patient management and treatment, and has also facilitated a Screening protocol to be instituted. The application of the techniques of molecular biology has enabled the identification of the gene causing MEN1 and the detection of mutations in patients. The function of the protein encoded by the MEN1 gene has been shown to be in the regulation of JunD-mediated transcription but much still remains to be elucidated. However, these recent advances provide for the identification of mutant MEN1 gene carriers who are at a high risk of developing this disorder and thus require regular and Biochemical Screening to detect the development of endocrine tumours.
Karl Oliver Kagan - One of the best experts on this subject based on the ideXlab platform.
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first trimester Screening for trisomy 21 by free beta human chorionic gonadotropin and pregnancy associated plasma protein a impact of maternal and pregnancy characteristics
Ultrasound in Obstetrics & Gynecology, 2008Co-Authors: Kevin Spencer, Karl Oliver Kagan, David Wright, Francisca S Molina, K H NicolaidesAbstract:Objectives To use multiple regression analysis to define the contribution of maternal variables that influence the measured concentration of free beta-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A), and the interaction between these covariates, in first-trimester Biochemical Screening for trisomy 21. Methods This was a multicenter study of prospective Screening for trisomy 21 by a combination of fetal nuchal translucency thickness, and maternal serum free β-hCG and PAPP-A at 11 + 0t o 13 + 6 weeks of gestation. In the pregnancies subsequently found to have trisomy 21 and in those with no obvious chromosomal abnormality, we used multiple regression analysis to account for pregnancy characteristics that influence the measured concentrations of free β-hCG and PAPP-A. We fitted Gaussian distributions to the distribution of log multiples of the median (MoM) values in trisomy 21 and in unaffected pregnancies. Results There were 491 cases of trisomy 21 and 96 803 chromosomally normal pregnancies. Compared with values in Caucasian women, those who were parous, non-smokers and those who conceived spontaneously, PAPP-A was 57% higher in women of Afro-Caribbean origin, 3% higher in South Asians, 9% higher in East Asians, 2% higher in nulliparous women, 17% lower in smokers and 10% lower in those conceiving by in-vitro fertilization (IVF). Free β-hCG was 12% higher in women of Afro-Caribbean origin, 9% lower in South Asians, 8% higher in East Asians, 2% higher in nulliparous women, 4% lower in smokers and 9% higher in those conceiving by IVF. In Screening for trisomy 21 by maternal age and serum free β-hCG and PAPP-A the estimated detection rate was 65% for a false-positive rate of 5%. Conclusions In first-trimester Biochemical Screening for trisomy 21 it is essential to adjust the measured values of free β-hCG and PAPP-A for maternal and pregnancy characteristics. Copyright 2008 ISUOG. Published by John Wiley & Sons, Ltd.
J M Connor - One of the best experts on this subject based on the ideXlab platform.
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first trimester Biochemical Screening for trisomy 21 the role of free beta hcg alpha fetoprotein and pregnancy associated plasma protein a
Annals of Clinical Biochemistry, 1994Co-Authors: Kevin Spencer, Jennifer A Crossley, D A Aitken, G Mccaw, E Berry, R W Anderson, J M ConnorAbstract:The potential efficacy of Screening for trisomy 21 in the first trimester, using maternal serum markers alpha fetoprotein, free beta human chorionic gonadotropin, unconjugated oestriol and pregnancy associated plasma protein A, was studied in an unselected population of women between the seventh and fourteenth week of gestation. Using a combination of alpha fetoprotein and free beta human chorionic gonadotropin, 53% of affected pregnancies could be identified at a false positive rate of 5%. Unconjugated oestriol and pregnancy associated plasma protein A levels were lower in cases of trisomy 21, but their inclusion with other markers did not significantly improve detection rate. Monitoring the same pregnancies also in the second trimester showed that Screening in the first trimester identified the same cases as in the second. We conclude that first trimester Screening using free beta human chorionic gonadotropin and alpha fetoprotein, is a viable possibility and will lead to detection rates in excess of 50%. Prospective studies are needed to confirm these observations.
S. Jansen - One of the best experts on this subject based on the ideXlab platform.
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Clinical studies of multiple endocrine neoplasia type 1 (MEN1)
QJM : monthly journal of the Association of Physicians, 1996Co-Authors: D Trump, B. Farren, C Wooding, J T Pang, G. M. Besser, K. D. Buchanan, C.r. Edwards, D A Heath, Charles E. Jackson, S. JansenAbstract:Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined occurrence of parathyroid, pancreatic islet and anterior pituitary tumours. To facilitate a Screening programme for MEN1, we investigated 709 people (364 males and 345 females, age range 1-84 years) from 62 MEN1 families, and 36 non-familial MEN1 patients. Of those investigated, 220 (95 males and 125 females, age range 8-79 years) suffered from MEN1. Parathyroid, pancreatic and pituitary tumours occurred in 95%, 41% and 30% of the patients, respectively. Parathyroid tumours were the first manifestation of MEN1 in 87% of patients, and amongst the pituitary and pancreatic tumours, somatotrophinomas and gastrinomas were more common in patients above the age of 40 years, whilst insulinomas occurred more frequently in patients below the age of 40 years. Biochemical Screening indicated that the penetrance of MEN1 by the ages of 20, 35 and 50 years was 43%, 85% and 94%, respectively, and that the development of MEN1 was confined to first-degree relatives in 91% of patients and to second-degree relatives in 9% of patients. These findings have helped to define a proposed Screening programme for MEN1.