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A Borrell

Publications and source records attributed to A Borrell.

At least 37 records · Page 2Linked to original sources
PubMed1999

Expression and cellular localization of Atrab28 during arabidopsis embryogenesis.

The maize abscisic acid (ABA)-responsive gene rab28 has been shown to be ABA-inducible in embryos and vegetative tissues, expression being mostly restricted to vascular elements during late embryogenesis. In the course of an expressed sequence tags (ESTs) programme, we have isolated an Arabidopsis thaliana gene, Atrab28, encoding the orthologue of maize rab28. The Atrab28 cDNA is 1090 bp long, including a poly(A)+ stretch, and encodes a polypeptide of 262 amino acids. Atrab28 antibody against the recombinant protein recognizes a polipeptide of about 30 kDa and pI 6, in close agreement with the predicted molecular mass and pI. As for maize rab28, expression studies with Atrab28 revealed high specificity for embryo tissues, transcription being stimulated by the transcriptional activator abi3. In contrast, Atrab28 was not induced in vegetative tissues by ABA, osmotic stress or dehydration. The expression of Atrab28 mRNA and the accumulation of Atrab28 protein was largely restricted to provascular tissues of mature embryos and in the seed coat outer tegument and embryo and silique epidermis, as revealed by in situ hybridization and immunocytochemistry with anti-Atrab28 antibodies.

Abscisic Acid↗
PubMed1999

Assaying the granulocyte-macrophage colony-stimulating factor (GM-CSF) as a mitogen of immature cells in fetal blood cultures.

Based on the presence of immature cells in fetal blood, and in an attempt to shorten the cytogenetic reporting time, three simultaneous one-day culture regimes were established in 23 fetal blood samples: (a) the standard phytohemagglutinin (PHA)-stimulated lymphocytes culture, (b) a culture using the granulocyte-macrophage colony-stimulating factor (GM-CSF) as an alternative mitogen, and (c) an unstimulated culture. Diagnostic success rates achieved by these three methods were as follows: 43 per cent (95 per cent CI: 23-64) (GM-CSF), 30 per cent (95 per cent CI: 12-49) (PHA) and 9 per cent (unstimulated). These three regimes were also assayed in three-day cultures giving 100 per cent diagnostic success rate for the PHA and GM-CSF, and 62 per cent (95 per cent CI: 41-83) for the unstimulated. A moderate correlation was found between the initial concentration of cultured erythroblasts and the metaphase count in one-day GM-CSF-stimulated (r=0.43, p=0.01) and unstimulated (r=0.35, p=0.05) cultures, suggesting that erythroblasts may be in part responsible for the mitotic index observed in these two regime cultures. In conclusion, our experience suggests that immature cells in fetal blood may be successfully cultured for diagnostic purposes.

Cells, Cultured↗
PubMed1999

First-trimester transcervical chorionic villus sampling by biopsy forceps versus mid-trimester amniocentesis: a randomized controlled trial project.

Up to now, no data are available comparing amniocentesis and chorionic villus sampling (CVS) using biopsy forceps. A series of 1313 consecutive women referred to our unit before 12 weeks of pregnancy for fetal cytogenetic analysis because of advanced maternal age, were randomized into CVS with the use of transcervical biopsy forceps or mid-trimester amniocentesis. The diagnostic success rates of the two groups were 98 per cent and 100 per cent, and a second procedure was needed in 4.1 per cent (13/314) and in 0. 3 per cent (1/358), respectively. Follow-up was achieved in 98.7 per cent of the pregnancies. Postprocedure spontaneous fetal losses, until the first week after birth, in the 672 pregnancies that completed the trial accounted for 2.2 per cent (7/314) in the CVS group and 2.8 per cent (10/358) in the amniocentesis group. Although the trial was prematurely discontinued, and therefore the sample size was smaller than initially planned, the results indicate that transcervical CVS was as safe as mid-trimester amniocentesis.

Adult↗
PubMed1998

Chromosome abnormalities in peripheral blood lymphocytes from Cebus apella (Cebidae, Platyrrhini) after X-ray irradiation.

In this paper, we describe the results of a qualitative and quantitative study of chromosomal reorganizations observed in X-irradiated (1Gy and 2Gy) and cultured lymphocytes from Cebus apella. A total of 646 breakpoints have been detected, identified and localized in the ideogram of the species. The breakpoint distribution along chromosomes, p and q arms, and bands is not random. Chromosomes #11, #12 and chromosome arms 1p, 12p, 13p, 15p, 11q, and 12q are significantly more affected than expected, while chromosome #19 and chromosome arm 19q are less affected. Terminal regions of chromosome arms accumulate a higher number of breakpoints than the rest of the chromosome (37.82%). A high percentage (93.66%) of breakpoints is found in G negative bands.

Animals↗
PubMed1998

Reversed end-diastolic umbilical flow in a first-trimester fetus with congenital heart disease.

Reversed end-diastolic umbilical artery velocities and a reduced chorionic sac were first seen at 10 weeks in a pregnancy subsequently showing a normal male karyotype on chorionic villi. Four weeks later Doppler studies demonstrated normal umbilical artery waveforms. At 20 weeks, ultrasound examination of the fetus revealed a mild pericardic effusion, hypoplastic righ heart with hypertrophic myocardium and a single umbilical artery, suggesting pulmonary atresia. After neonatal death, pathological studies confirmed pulmonary atresia. This case suggests that reversed end-diastolic umbilical flow in the first trimester may identify a subgroup of fetuses with a lethal abnormality (heart defect, severe intra-uterine retardation, aneuploidy or others).

Adult↗
PubMed1998

Abnormal ductus venosus blood flow in trisomy 21 fetuses during early pregnancy.

OBJECTIVE: Our purpose was to assess the ductus venosus blood flow in trisomy 21 fetuses in the first half of pregnancy and the relation of this blood flow to nuchal thickness. STUDY DESIGN: The ductus venosus blood flow has been studied in 534 consecutive fetuses between 10 and 18 weeks of gestation who were undergoing prenatal invasive diagnostic procedures. Before the sampling, the velocity during atrial contraction, the pulsatility index for veins, and the ratio of systole-end-systole to diastole were established in the Doppler waveforms and eventually correlated with the fetal karyotype. RESULTS: Ductus venosus waveforms were successfully obtained in 82% of the pregnancies. Eleven fetuses were found to have trisomy 21; the pulsatility index was abnormally increased (>95th percentile) in 73% (8/11), the ratio of systole-end-systole to diastole was abnormally increased in 45% (5/11), and the velocity during atrial contraction was decreased (<5th percentile) in 27% (3/11). CONCLUSIONS: An abnormally increased ductus venosus pulsatility index was found in a substantial proportion of early trisomy 21 fetuses, and this was apparently independent of nuchal thickening.

Blood Circulation↗
PubMed1998

Natural evolution of nuchal thickness in trisomy-21 fetuses.

OBJECTIVE: To assess the natural evolution of nuchal thickness in trisomy-21 fetuses. METHODS: Serial measurements of nuchal thickness were performed over a 1- to 6-week period in 45 consecutive fetuses with trisomy 21, between the 10th and the 23rd weeks of pregnancy. To avoid a gestational age confounding effect, nuchal thickness also was expressed in standard deviations (SDs) for the corresponding gestational week. In addition, the changes were assessed in terms of the presence of clinical positive thickening, considered as such when the measurement was above 2.5 SD. RESULTS: A mean increase of 1.8 mm (95% confidence interval [CI] 1.3, 2.3) for nuchal thickness was observed for a mean period of 21 days. When corrected by gestational age, the mean increase of 0.3 SD (95% CI -0.2, 0.9) was found to be not significant. No clinically relevant nuchal thickening changes were recorded (51% versus 69%) at re-examination. CONCLUSION: Nuchal thickening at re-examination is observed in a similar proportion of trisomy-21 fetuses as when first observed.

Down Syndrome↗
PubMed1998

Fetal heart rate and nuchal translucency in detecting chromosomal abnormalities other than Down syndrome.

OBJECTIVE: To evaluate whether the combined use of fetal heart rate (FHR) and nuchal translucency measurements would be useful in the prediction of fetal chromosomal abnormalities at 10-13 weeks' gestation. METHODS: In a prospective study, 1053 (553 reported previously) consecutive singleton pregnancies between 10 and 13 weeks' gestation underwent chorionic villus sampling at our institution. Fetal heart rate and fetal nuchal translucency thickness were measured immediately before the invasive procedure. RESULTS: Thirty-five abnormal karyotypes were diagnosed, including 17 trisomy 21, seven trisomy 18, one trisomy 13, one trisomy 9, four unbalanced translocation, two Klinefelter syndrome, one Turner syndrome, one deletion of chromosome 18, and one true mosaicism. Using 95% of normal ranges as the cutoff for both measurements, the detection rate for all chromosomal anomalies was 77.1%, with a false-positive rate (1-specificity) of 7.7%, a positive predictive value of 25.7%, and a negative predictive value of 99.2%. Fetal heart rate improved the sensitivity of nuchal thickness in trisomies 21 and 18 (from 62.5% to 75%) and was particularly useful to detect other chromosomal anomalies (from 27.2% to 81.8%). CONCLUSION: Our findings suggest that there is an added role of FHR in ultrasound screening of chromosomal abnormalities, specifically for those other than trisomy 21 and 18. The value of a single measurement of fetal heart rate for screening purposes needs to be confirmed by further investigation in a low-risk population.

Adult↗
PubMed1997

Brachycephaly is ineffective for detection of Down syndrome in early midtrimester fetuses.

The aim of this study was to assess the value of fetal brachycephaly in the detection of Down syndrome at 13-18 weeks of pregnancy. The cephalic index (CI) was determined in 555 consecutive chromosomally normal fetuses, and in 38 chromosomal abnormalities, prior to amniocentesis. A CI > 0.85 was observed in 14% (2/14) of the fetuses with Down syndrome and in 11% of the normal fetuses. In conclusion, our data show that brachycephaly is not a useful marker for Down syndrome in early midtrimester fetuses.

Adolescent↗
PubMed1997

Umbilical Doppler velocimetry in fetuses with trisomy 18 at 10-18 weeks' gestation.

The aim of our study was to obtain measurements of the umbilical artery pulsatility index (PI) in pregnancies before invasive procedures for prenatal diagnosis, in order to investigate its potential prognostic value in predicting trisomy 18. We performed a prospective study including 1785 consecutive women from 10 to 18 weeks with singleton pregnancies undergoing chorionic villus sampling (n = 559) or genetic amniocentesis (n = 1226) in our unit. Doppler measurements were performed transvaginally (tenth to 13th week of gestation) or transabdominally (14th to 18th week of gestation) immediately before the invasive procedure. In 7 out of 10 fetuses subsequently diagnosed as trisomy 18, the PI was above the 95th centile, providing a detection rate of 70 per cent, a specificity of 95.1 per cent, a positive predictive value of 7.7 per cent, and a negative predictive value of 99.8 per cent. When the 90th percentile was assayed as a cut-off, the efficacy of PI as a marker of trisomy 18 yielded a sensitivity of 90 per cent and a specificity of 90.4 per cent, with a positive predictive value of 5.2 per cent and a negative predictive value of 99.9 per cent. We suggest that although the use of a single PI measurement for screening purposes needs to be confirmed by further investigation, trisomy 18 fetuses show an abnormal increase in umbilical PI in the first half of pregnancy, and its relation to the early onset of fetal growth retardation needs to be further explored.

Blood Flow Velocity↗
PubMed1997

Interobserver variability of midtrimester fetal nuchal thickness.

OBJECTIVE: To assess the interobserver variability of ultrasound measured fetal nuchal thickness (NT). STUDY DESIGN: NT was measured in 103 consecutive early midtrimester pregnancies (13-18 weeks) by three ultrasonographists with different levels of expertise, in our Prenatal Unit. Measurements were obtained prior to amniocentesis, blindly in relation to other examiners' values. The Lin's concordance correlation coefficient and the Kappa statistics were used to assess concordance between observed values. RESULTS: Mean differences between pairs of observers ranged from 0.44 to 0.57 mm. A higher concordance correlation between measurements was obtained between the more experienced observers (r = 0.77 versus r = 0.51). When assigning cases with a NT > or = 5 mm to a group at risk for Down's syndrome, a high concordance between experienced ultrasonographists was observed (98% agreement; kappa = 0.90). CONCLUSIONS: Interobserver variability in NT was acceptable between experienced ultrasonographists.

Adult↗
PubMed1997

Combining nuchal translucency with umbilical Doppler velocimetry for detecting fetal trisomies in the first trimester of pregnancy.

OBJECTIVE: The aim of our study was to evaluate whether the combined use of umbilical artery pulsatility index (UAPI) and nuchal translucency (NT) measurements would be useful in the prediction of fetal chromosomal abnormalities at 10 to 13 weeks of gestation. DESIGN: A prospective study. POPULATION AND METHODS: Five hundred and fifty-three consecutive women with singleton pregnancies between 10 and 13 weeks of gestation, who underwent chorionic villus sampling at our institution. UAPI and fetal NT thickness were measured immediately before the invasive procedure. Pregnancies in which structural malformations had been detected by ultrasound were excluded. RESULTS: Using the 95th centile and 3 mm as the cutoffs for UAPI and NT, respectively, the detection rate for all chromosomal anomalies was 84.2%, with a false positive rate (1-specificity) of 6.6%, a positive predictive value of 31.3%, and a negative predictive value of 99.4%. Out of the 553 tested pregnancies 502 had both parameters within the normal range and only three of them (0.6%) were chromosomally abnormal; in six of the eight cases (75%) in which both parameters were abnormal a chromosome anomaly was present. Of the 43 cases in which only one parameter was abnormal, 10 were chromosomally abnormal (23.2%). CONCLUSIONS: Our results suggest that the presence of chromosomal anomalies may be strongly suspected when an increased NT thickness (NT > or = 3 mm) is associated with an abnormally high UAPI at 10 to 13 weeks of gestation. The number of cases studied is small, however, and these conclusions are tentative and preliminary. The value of a single measurement of NT and UAPI for screening purposes needs to be substantiated by further investigation.

Adult↗
PubMed1997

Criteria for fetal nuchal thickness cut-off: a re-evaluation.

An attempt has been made to establish a more effective cut-off criterion for nuchal thickness (NT) and to assess the optimal gestational period for the prediction of trisomies 21 and 18. Reference intervals were established for NT from the tenth to the 18th week, using either gestation-specific centiles or the parametric method. The measurements in 47 consecutive trisomy 21 and 18 trisomy 18 cases were plotted against these intervals. Assaying different cut-off criteria for both the centile and the parametric methods, sensitivities and false-positive rates for each gestational week were calculated and then compared with the commonly applied 'two-stepped' cut-off method (3 mm early, 6 mm later). The parametric method, based on a progressive rise, with +2.5 SD for the corresponding gestational week as a cut-off value, showed the best performance (likelihood ratio 38) in the prediction for trisomy 21. The optimal gestational age was the 12-18 week period, with an overall sensitivity of 62 per cent (23/37) for an average false-positive rate of 0.7 per cent. For trisomy 18, the most effective cut-off was also +2.5 SD, and 10-13 gestational weeks as the optimal period, achieving 86 per cent (6/7) sensitivity for a 1.9 per cent false-positive rate.

Chromosome Aberrations↗
PubMed1996

Doppler assessment of umbilical flow after genetic amniocentesis.

The aim of our study was to evaluate the immediate changes on the fetal heart rate (FHR) and the fetal umbilical artery pulsatility index (UPI) after performing genetic amniocentesis. This was a prospective study including 431 consecutive singleton pregnancies between 14 and 18 weeks undergoing genetic amniocentesis in our institution. Doppler measurements were obtained transabdominally before and immediately after the procedure. Structural malformations detected by ultrasound were excluded. Student's t-test was performed for comparisons among different groups and observed mean changes. The results showed a significant decrease in FHR post-amniocentesis (mean 1.5 beats, t = 3.47, P < 0.01) and a non-significant elevation in UPI (mean -0.01, t = -0.29, P = 0.77) after the procedure. Differences in FHR could be found when analyzed by each gestational week. These preliminary data suggest that although acute fetal hemodynamic changes are detected after genetic amniocentesis, such changes are unlikely to have clinical relevance. However, it is reasonable to propose the use of Doppler as a method of assessing hemodynamic effects caused by prenatal invasive procedures in order to provide more accurate in vivo research on this issue.

Adult↗
PubMed1996

Immediate changes in umbilical blood flow after transcervical chorionic villus sampling performed by biopsy forceps.

Transvaginal ultrasonography with colour Doppler was used to evaluate the immediate changes on the fetal heart rate (FHR) and the fetal umbilical artery pulsatility index (PI) after chorionic villus sampling (CVS). This prospective study included 279 consecutive singleton pregnancies, between 10 and 13 weeks, of women who underwent transcervical CVS in our institution. All Doppler measurements were obtained transvaginally before and immediately after CVS. Structural malformations detected by ultrasound were excluded. Student's t- and Wilcoxon texts were performed for statistical analysis. The results showed no significant decrease in FHR (mean 1.04 beats, t = 1.68, P = 0.94) and a significant elevation of umbilical artery PI (mean 0.12, t = - 6.51, P < 0.001) post-CVS. This difference was only significant in procedures performed at less than 11 weeks' gestation, since there was no significant change for those procedures performed thereafter. These preliminary data suggest that acute fetal haemodynamic changes are induced by CVS and may have clinical effects. Hypotheses on possible vascular mechanisms are discussed. Colour Doppler could widen the possibilities for more accurate in vivo assessment and research on CVS-related placental injury.

Abortion, Spontaneous↗
PubMed1996

First-trimester biochemical screening for Down syndrome with the use of PAPP-A, AFP, and beta-hCG.

Biochemical screening for Down syndrome (DS) is well established in the second trimester of pregnancy, but there is little information available on its value in the first trimester. This study describes our preliminary results with biochemical screening for DS in the first trimester of pregnancy in order to evaluate its efficacy at this time. Our study population, including 19 DS pregnancies, was evaluated using maternal serum levels of alpha-fetoprotein (AFP), beta-human chorionic gonadotropin (beta-hCG), and pregnancy-associated plasma protein A (PAPP-A). At a false positive rate (FPR) of 5 per cent, the detection rate (DR) for DS is 9 per cent for beta-hCG, 18 per cent for AFP, and 66 per cent for PAPP-A when considering these parameters individually. With different combinations of the analytes, the best detection rates are obtained with the association of PAPP-A and AFP (85 and 82 per cent DR for a 10 and 5 per cent FPR, respectively). Our data support the value of first-trimester biochemical screening for DS and that of PAPP-A as a single marker.

Adult↗
PubMed1996

Fetal heart rate patterns in pregnancies with chromosomal disorders or subsequent fetal loss.

OBJECTIVE: To evaluate whether an abnormal fetal heart rate (FHR) is associated with chromosomal abnormalities in pregnant women undergoing an invasive procedure for prenatal diagnosis, and to investigate an abnormal FHR's potential value in predicting fetal loss in chromosomally normal pregnancies after the procedure. METHODS: This was a prospective study including 867 women, all consecutive singleton pregnancies at 10-18 weeks' gestation, who underwent chorionic villus sampling (n = 371) or genetic amniocentesis (n = 496) at our institution. Fetal heart rate, expressed as beats per minute, was measured before the invasive procedure. Structural malformations detected by ultrasound were excluded. RESULTS: Chromosomal abnormalities were diagnosed in 25 fetuses, including 11 with trisomy 21. In ten of 25 fetuses with chromosomal abnormalities, the FHR was between the fifth and 95th percentiles established before the procedure for the chromosomally normal group with normal outcome. Using the fifth percentile as a cutoff for trisomy 21, the detection rate was 63.6%, with a specificity of 96.2% and a positive predictive value of 17.9% (one in 5.5) in our population. Moreover, in six of the ten chromosomally normal miscarriages occurring within 4 weeks after the procedure, the FHR was above the 95th percentile. CONCLUSION: Although the value of a single measurement for screening purposes needs to be confirmed by further investigation, our preliminary data suggest that chromosomal anomalies, especially trisomy 21, may be suspected in fetuses with an abnormally low FHR in early pregnancy. In chromosomally normal fetuses, the detection of an abnormally high FHR in some degree may be predictive of fetal loss after the invasive procedure.

Adult↗