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Biomedical subjects

B Brambati

Publications and source records attributed to B Brambati.

At least 19 recordsLinked to original sources
PubMed1995

Crown-rump length in aneuploid fetuses: implications for first-trimester biochemical screening for aneuploidies.

This study examined the effect of estimation of gestational age from the menstrual history compared with that from crown-rump length (CRL) measurement on the detection rate of screening for aneuploidies in the first trimester. Pregnancy-associated plasma protein A (PAPP-A) was assayed in blood collected prior to chorionic villus sampling in 356 women with unaffected pregnancies and 28 women with an aneuploid pregnancy. There were 14 Down's syndrome (DS) pregnancies. All pregnancies were dated from menstrual history and CRL measurement. The average CRL gestation in the aneuploid population was 2.5 days less than that derived from the LMP (95 per cent confidence interval (CI) for LMP-CRL gestation: using the algorithm based on unaffected pregnancies 0-3.5 days; using the matched case-control approach 1-4.5 days). The average CRL gestation in the DS population was 2 days less but this did not reach statistical significance (95 per cent CI for LMP-CRL gestation: using the algorithm -1 to 4.5 days; using the matched case-control approach 0 to 5.5 days). The detection rate of aneuploidies in the first trimester using maternal serum PAPP-A was reduced by 7 per cent (and by 3 per cent for DS) for a 5 per cent false-positive rate when using CRL rather than LMP to date the pregnancy. This phenomenon is a consequence of an apparent reduction of gestational age when estimated by CRL in the aneuploid population. Further studies are required to evaluate whether CRL is an unbiased estimate of gestation for Down's syndrome pregnancies.

Aneuploidy↗
PubMed1995

Somatic stability in chorionic villi samples and other Huntington fetal tissues.

We have studied different tissues from two affected fetuses with Huntington's disease (HD). In the first case the analysis was performed at 11 weeks of pregnancy; CAG repeats from seven different tissues were compared with the results obtained in the chorionic villi sample (CVS). We found 42 CAG repeats in all samples. In the second case the study was done at 12 weeks; eight tissues (including brain) were studied and compared with the CVS; in all of them, 44 CAG repeats were obtained. Our results show a somatic stability in the different analyzed tissues and suggest that mitotic instability can be a secondary consequence of neuronal degeneration and gliosis. Likewise, our data show great viability in the prenatal diagnosis (PD) of Huntington's disease using samples from any tissue.

Abortion, Therapeutic↗
PubMed1995

First-trimester Down's syndrome screening using nuchal translucency: a prospective study in patients undergoing chorionic villus sampling.

The value of the measurement of nuchal translucency thickness for predicting fetal Down's syndrome and other aneuploidies was prospectively evaluated at 8-15 weeks of gestation in 1819 consecutive pregnancies scheduled for karyotyping by chorionic villus sampling. In 43 cases, a chromosomal unbalanced aberration was found. Two teams of ultrasonologists who examined patients attending either National Health Service (Series 1) or private practice clinics (Series 2) were involved in the study. The same type of ultrasound machine and standardized approach were used in both study groups. In those cases in which the maximum subcutaneous thickness of the translucency was 3 mm or greater, the incidence of chromosomal aberration was 18.6% compared to 1.7% in the cases in which this was below 3 mm. The sensitivity, specificity and relative risk for all aneuploidies were 30%, 96% and 10.83, respectively, and no difference was found between trisomy 21 and other types of aneuploidy. The sensitivity and specificity and relative risk were significantly higher at 9-10 weeks than between 11 and 15 weeks. The results were concordant in the two series; however, the overall values for sensitivity (20% vs. 39%), specificity (94% vs. 98%) and relative risk (4.13 vs. 24.20) were clearly higher in the group of private patients. The results obtained confirm the potential application of the measurement of nuchal translucency thickness for fetal aneuploidy screening before the end of the first trimester and suggest that a multiplicity of individual, structural and organizational factors may interact and play a crucial role in determining the actual efficiency of ultrasound screening programs.

Adult↗
PubMed1995

The Euro-Team Early Pregnancy (ETEP) protocol for recurrent miscarriage.

The underlying causes and rationale for treatment of recurrent abortion are not entirely clear. The Euro-Team early pregnancy protocol was developed as a diagnostic work-up based on the evaluation of risk factors. Possibilities for therapy can be based only on the expectancy that elimination of some risk factors may improve the prognosis.

Abortion, Habitual↗
PubMed1995

Genetic analysis prior to selective fetal reduction in multiple pregnancy: technical aspects and clinical outcome.

Multiple pregnancies resulting from ovarian stimulation are at a higher risk of carrying at least one fetus affected by Mendelian or chromosomal anomalies, the incidence of which is directly related to the order of multiples. Genetic analysis before fetal reduction was offered to both high- and low-risk pregnant women carrying two or more fetuses after ovulation induction. Chorionic villus sampling (CVS) and fetal reduction were achieved by transabdominal needling. The use of short-term culture, the polymerase chain reaction and fresh tissue enzymatic analyses have made it possible for genetic diagnosis to be available in a few days. A total of 100 patients had multifetal pregnancy reduction performed by a single operator; all of them completed pregnancy and none was lost at follow-up. The total fetal loss before 24 weeks was 7% and no statistically significant relationship was found with the final number of fetuses and CVS. Perinatal losses (3.9%) were only present in the series with a final number of two fetuses. Pregnancy duration and birthweight were significantly higher in singletons than in twins, but were not related to CVS. The rate of chromosomal disorders was higher (7.2%) in the study series than in singleton pregnancies not undergoing fetal reduction. Diagnostic error due to incorrect sampling was reported in 1.5% of cases. These data support fetal reduction as a valuable strategy to improve the outcome of multiple pregnancy. The outcome of pregnancies reduced to singletons was significantly better than of those reduced to twins, and was not related to CVS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Chorionic villus sampling.

Chorionic villus sampling (CVS) has the great advantage over mid-trimester amniocentesis of producing early results. Moreover, rapid analytic techniques have significantly reduced the waiting time between sampling and diagnosis, whereas progress in recombinant DNA technology and human gene mapping has led to an increase in the range of conditions it can detect. The role of CVS in twin pregnancy has been investigated and compared with amniocentesis. Although these techniques are equally safe, CVS should be considered the approach of choice because of a number of technical advantages, and in relation to selective fetal reduction in discordant twins. Confined placental mosaicism has been investigated and a list of chromosomes related to adverse pregnancy outcome has been compiled. Recent reports have substantially contributed to solving the controversy on the hypothetical relationship between limb reduction defects and CVS. Analysis of limb reduction defects among more than 130,000 cases reported to the World Health Organization CVS registry has been unable to find any relationship between sampling and fetal malformations, including limb reduction defects.

Chorionic Villi Sampling↗
PubMed1994

Serum PAPP-A and free beta-hCG are first-trimester screening markers for Down syndrome.

Serum measurements of pregnancy-associated plasma protein A (PAPP-A) and the free beta-human chorionic gonadotrophin (hCG) subunit were made in 13 women with Down syndrome (DS) pregnancies and six other women with fetal aneuploidy ascertained at chorionic villus sampling (CVS), as well as 89 women with contemporaneous normal control pregnancies. Median serum PAPP-A measurements (0.31 MOM, 95 per cent confidence interval (CI) 0.22-0.65 vs. normal 1.06, 95 per cent CI 0.89-1.20) were lower and free beta-hCG subunit measurements (1.13 MOM, 95 per cent CI 0.93-2.63 vs. normal 0.91, 95 per cent CI 0.79-1.03) were higher at statistically significant levels. Receiver operator characteristics (ROC) curves showed that the highest sensitivity for detection, 71.2 per cent (95 per cent CI 54.7-87.6 per cent), was for depressed PAPP-A levels; the combination of low serum PAPP-A levels, maternal age, and elevated free beta-hCG levels yielded a detection rate of 78.9 per cent (95 per cent CI 64.9-92.8 per cent) of the affected pregnancies at 8-12 weeks' gestation.

Adult↗
PubMed1994

Multiple pregnancy induction and selective fetal reduction in high genetic risk couples.

Couples at risk for an inherited disorder often have several pregnancy interruptions because of affected fetuses and difficulty in achieving their desired family. We evaluated the efficiency and acceptability of selective fetal reduction after chorionic villus sampling (CVS) of multiple pregnancy induced by ovarian stimulation and gamete intra-Fallopian transfer (GIFT). This approach has been offered to nine patients at risk of Mendelian diseases and one patient carrier of reciprocal translocation. The acceptance has been very high (90%). One patient at risk of an autosomic recessive disease opted for artificial donor insemination, one conceived spontaneously, and one was a poor responder to ovarian stimulation. Seven patients actually underwent a single GIFT procedure with six achieving pregnancy (86%), all but two being a multiple pregnancy (67%). All pregnancies concluded uneventfully at term and newborns were alive and healthy. Prenatal diagnosis, including fetal karyotyping in all cases, was performed at 8.5-11.5 weeks of gestation and confirmed either on amniotic fluid aspirated at reduction or at birth. The number of fetuses was reduced to one or two because the genetic disease was present and/or to reduce the risk of premature delivery and improve the likelihood of successful pregnancy. The new approach seems to be highly effective and might be considered a practical and useful alternative to preimplantation genetic diagnosis.

Abortion, Induced↗
PubMed1993

Low maternal serum levels of pregnancy associated plasma protein A (PAPP-A) in the first trimester in association with abnormal fetal karyotype.

OBJECTIVE: To assess the relation between maternal serum pregnancy associated plasma protein A (PAPP-A) in the first trimester and the outcome of pregnancy by karyotype. DESIGN: A retrospective study of PAPP-A levels in blood samples collected prior to chorionic villus sampling. SETTING: Milan, Italy. SUBJECTS: Five hundred twenty-two women aged 20 to 47, at 7 to 11 weeks gestation, prior to undergoing chorionic villus sampling. Four hundred forty-five women had a pregnancy with a normal karyotype; in 30 pregnancies the karyotype was abnormal (including 14 cases of Down's syndrome and 7 of trisomy 18). MAIN OUTCOME MEASURES: Normal or abnormal fetal karyotype. Serum PAPP-A at 6 to 11 weeks gestation measured by radioimmunoassay. RESULTS: The median value of PAPP-A in the abnormal group was 0.27 multiples of the normal median (MoM). This is significantly lower than the median value in the normal group (1.01 MoM) (95% CI for the difference 0.46-0.84 MoM; P < 0.00001 Mann-Whitney test). CONCLUSIONS: There is an association between low levels of PAPP-A in the first trimester with chromosome anomalies. Screening by measurement of PAPP-A might detect 60% of cases of Down's syndrome in the first trimester with a false positive rate of 5%.

Adult↗
PubMed1993

Predicting fetal chromosome anomalies in the first trimester using pregnancy associated plasma protein-A: a comparison of statistical methods.

The analysis of the clinical efficiency of a biochemical parameter in the prediction of chromosome anomalies is described, using a database of 475 cases including 30 abnormalities. A comparison was made of two different approaches to the statistical analysis: the use of Gaussian frequency distributions and likelihood ratios, and logistic regression. Both methods computed that for a 5% false-positive rate approximately 60% of anomalies are detected on the basis of maternal age and serum PAPP-A. The logistic regression analysis is appropriate where the outcome variable (chromosome anomaly) is binary and the detection rates refer to the original data only. The likelihood ratio method is used to predict the outcome in the general population. The latter method depends on the data or some transformation of the data fitting a known frequency distribution (Gaussian in this case). The precision of the predicted detection rates is limited by the small sample of abnormals (30 cases). Varying the means and standard deviations (to the limits of their 95% confidence intervals) of the fitted log Gaussian distributions resulted in a detection rate varying between 42% and 79% for a 5% false-positive rate. Thus, although the likelihood ratio method is potentially the better method in determining the usefulness of a test in the general population, larger numbers of abnormal cases are required to stabilise the means and standard deviations of the fitted log Gaussian distributions.

Adult↗