Increased fetal DNA in maternal plasma/serum has been reported in pregnancies complicated by preeclampsia. We hypothesized that impaired clearance of fetal DNA might contribute, at least in part, to ...the above-mentioned phenomenon.
We studied 7 preeclamptic and 10 control pregnant women. All had male fetuses. Serial blood samples were obtained from before delivery to 6 h postpartum. Male fetal DNA in maternal plasma was measured by real-time quantitative PCR for the SRY gene on the Y chromosome.
The median fetal DNA concentrations before delivery were significantly higher in the preeclamptic women than in the controls (521 vs 227 genome-equivalents/mL for preeclamptic and control women, respectively; Mann-Whitney rank-sum test, P = 0.017). The median fetal DNA concentrations at 6 h after delivery were also significantly different between the two groups (208 vs 0 genome-equivalents/mL for preeclamptic and control women, respectively; Mann-Whitney rank-sum test, P = 0.002). A first-order clearance model was found to best describe the kinetics of maternal plasma fetal DNA clearance. Moreover, we observed a significant difference in the median apparent clearance half-lives of fetal DNA between the preeclamptic women (114 min) and controls (28 min; Mann-Whitney rank-sum test, P = 0.007).
This study represents the first documentation of impaired fetal DNA clearance from maternal plasma in preeclampsia. Such an abnormality in circulating DNA clearance may also be present in other medical conditions associated with quantitative aberrations in circulating DNA concentrations.
The discovery of cell-free fetal DNA in maternal plasma has opened up new possibilities for noninvasive prenatal diagnosis and monitoring. Among the fetal markers that have been described, ...methylation markers are sex and polymorphism independent. Methylation-sensitive restriction endonucleases are commonly used to digest hypomethylated DNA molecules, and the hypermethylated molecules remain intact for detection. The positive detection of the cleaved hypomethylated molecules would be useful for certain targets but has not been reported.
The use of a stem-loop primer in microRNA detection has previously been described. In this study, DNA assays were designed and performed on maternal plasma, which contained the hypomethylated placental serpin peptidase inhibitor, clade B (ovalbumin), member 5 (SERPINB5; maspin) gene in an excess background of hypermethylated maternal SERPINB5. Detection of the enzyme-digested placenta-derived hypomethylated SERPINB5 molecules was achieved by performing stem-loop extension followed by real-time PCR on maternal plasma. The placental origin of the stem-loop-extended SERPINB5 molecules was confirmed by genotyping.
From the real-time PCR results on maternal plasma, stem-loop-extended SERPINB5 promoter sequences were detectable in all 11 enzyme-digested predelivery maternal plasma samples. Postpartum clearance was demonstrated. In 9 cases in which the fetal and maternal SERPINB5 genotypes were distinguishable, the placental-specific genotypes were detected in all predelivery maternal plasma samples.
Detection of restriction enzyme-digested hypomethylated placental DNA molecules in maternal plasma by the use of a stem-loop primer represents a novel approach in fetal epigenetic marker detection. The analytical approach may also be generally applicable to the detection of restriction enzyme-digested nucleic acid fragments.
The molecular characteristics of placental RNA circulating in maternal plasma are unknown. We investigated the integrity of circulating placental RNA in maternal plasma and tested the relevance of ...plasma RNA integrity for noninvasive prenatal diagnosis.
Six different placental transcripts and mRNA of the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were quantified for the 5' and 3' regions in maternal plasma by 1-step real-time reverse transcription-PCR (RT-PCR) assays. This quantitative strategy was validated by 2-step RT-PCR and serial dilution experiments. The rates of detection by the 5' and 3' assays for the beta-subunit of human chorionic gonadotropin (beta hCG) were assessed in maternal plasma samples collected from different gestational periods.
For 5 of the 7 genes, the plasma mRNA concentrations measured by the 5' amplicons were significantly higher than those measured by the corresponding 3' amplicons. Every transcript under study demonstrated a higher rate of detection in the 5' assay than in the 3' assay in maternal plasma. In particular, the detection rate of beta hCG mRNA in maternal plasma was increased throughout gestation when the 5' assay was used.
Circulating placental RNA is associated with a preponderance of 5' mRNA fragments in maternal plasma. Apart from its intrinsic biological interest, this information could have important implications for the development of new assays targeting fetal RNA markers for noninvasive prenatal diagnosis and monitoring.
Juvenile idiopathic arthritis (JIA) is the most common type of inflammatory arthritis in children. Treatment options have been expanded since the introduction of biologics, which are highly ...effective. The existing local JIA treatment guideline was published more than a decade ago, when use of biologics was not as common. In this article, we review the latest evidence on using biologics in three JIA subtypes: JIA of polyarticular course (pcJIA), enthesitis-related arthritis (ERA), and psoriatic arthritis (PsA). Based on the latest information, an update on eligibility, response assessment, termination, and safety information for using biologics in these patients was performed.
The JIA Work Group, which consisted of nine paediatricians experienced in managing JIA, was convened in 2016. Publications before July 2017 were screened. Eligible articles were clinical trials, extension studies, systemic reviews, and recommendations from international societies and regulatory agencies about the use of biologics in pcJIA, ERA, and PsA. Evidence extraction, appraisal, and drafting of propositions were performed by two reviewers. Extracted evidence and drafted propositions were presented and discussed at the first two meetings. Overwhelming consensus was obtained at the final meeting in May 2018. Seven practice consensus statements were formulated. Regular review should be performed to keep the practice evidence-based and up-to-date.
Thalassaemia screening in pregnancy Leung, Tse N; Lau, Tze K; Chung, Tony Kh
Current opinion in obstetrics & gynecology,
04/2005, Letnik:
17, Številka:
2
Journal Article
Recenzirano
This review provide an update on antenatal screening and diagnosis of thalassaemia disorders.
The topics covered are the effectiveness of antenatal screening programmes for thalassaemia, its prenatal ...diagnosis, molecular basis and laboratory findings, ultrasound screening for haemoglobin Bart's disease, and non-invasive prenatal diagnosis of thalassaemia.
Universal antenatal screening for thalassaemia carriers should be implemented in populations with a high prevalence of this condition. The appropriate measure to screen for alpha and beta thalassaemias remains mean cell haemoglobin (<27 pg) or mean corpuscular volume (<80 fl). A haemoglobin pattern and iron profile should follow if the red cell indices are low. In a population where alpha thalassaemia is prevalent, it is advisable to check the partner's mean cell haemoglobin or mean corpuscular volume as well. Further cascades of investigations will depend on these results and the prevalence of other haemoglobinopathies in that population. Invasive prenatal diagnosis remains the gold standard for diagnosis in high-risk couples. Provided expertise is available, ultrasound measurement of the cardiothoracic ratio appears a good screening tool for alpha thalassaemia major. Non-invasive prenatal diagnosis by identification of a paternal mutation in maternal plasma, although currently at the experimental stage, may be an option in the future.
Fetal DNA is present in maternal plasma, and a proportion of such DNA is seen in intact fetal cells. We investigated the use of fluorescence in-situ hybridisation (FISH) techniques on maternal plasma ...samples. In plasma samples obtained from three women carrying fetuses affected by trisomy 21 (Down's syndrome), we identified fetal cells with three chromosome-21 signals. These results show the feasibility of non-invasive detection of fetal chromosomal aneuploidy by maternal plasma analysis.
Maternal blood was collected into EDTA-containing tubes before amniocentesis, and plasma was harvested by centrifugation at 1600g for 10 min at 4 °C, with the plasma portion recentrifuged at 16 0% ...for 10 min at 4 °C. Two milliliters of amniotic fluid were drawn and centrifuged at 16 000g for 10 min at 4 °C. The supernatant was removed and filtered by a 0.220-µm filter to obtain the cell-free portion.
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