Non-invasive cell-free DNA prenatal screening for trisomy 21 as part of primary screening strategy in twin pregnancies.

OBJECTIVES: The performance of non-invasive prenatal screening using cell-free DNA testing in maternal blood in twin pregnancies is still under-evaluated, while serum marker-based strategies yield poor results. This study aims at assessing the performance of non-invasive prenatal screening for trisomy 21 in twin pregnancies as a first-tier test. The secondary objectives were to assess the failure rate and associated factors. METHODS: This retrospective cohort study included twin pregnancies for which non-invasive prenatal screening using cell-free DNA was performed as the primary screening strategy between May 2017 and October 2019. We used the NIPT VeriSeq® test for in vitro diagnosis and set a fetal fraction cut-off of 4% for monochorionic pregnancies and 8% for dichorionic ones. Clinical data and pregnancy outcome was collected from either physicians or midwives through a questionnaire or were retrieved directly on site. We calculated the performance of non-invasive cell free DNA screening for trisomy 21 and analyzed failure rate and factors. RESULTS: We included 2577 multiple pregnancies among which 1885 (84.8%) were retained after excluding vanishing twins and pregnancies without follow-up. Overall, there were six confirmed trisomy 21 cases (0.32%). For trisomy 21, sensitivity was 100% (95% CI, 61-100%) and the false-positive rate 0.2% (95% CI, 0.07-0.6%). The primary failure rate was 4.6% with 4% due to insufficient fetal fraction. After a new blood draw (59.8% of failed cases), failure rate was only 1.5%. Body mass index and chorionicity were significantly correlated with the risk of failure. CONCLUSION: This study adds further evidence on the high performance of NIPS in twins, as part of the primary screening strategy for trisomy 21, at an extremely low false-positive rate. This article is protected by copyright. All rights reserved.

Network of co-expressed circadian genes, childhood maltreatment and sleep quality in bipolar disorders.

Bipolar disorder (BD) is a chronic and burdensome psychiatric disease, characterized by variations in mood and energy. The literature has consistently demonstrated an association between BD and childhood maltreatment (CM), and genetic variants of circadian genes have been associated with an increased vulnerability to develop BD. In this context, environmental factors such as CM may also contribute to the susceptibility to BD through alterations in the functioning of the biological clock linked to modifications of expression of circadian genes. In this study, we explored the associations between childhood maltreatment, sleep quality, and the level of expression of a comprehensive set of circadian genes in lymphoblastoid cell lines from patients with BD. The sample consisted of 52 Caucasian euthymic patients with a diagnosis of BD type 1 or type 2. The exposure to CM was assessed with the Childhood Trauma Questionnaire (CTQ), and the sleep quality was assessed using the Pittsburgh Sleep Quality Index. We measured the expression of 18 circadian genes using quantitative RT-PCR: ARNTL2, BHLHE40, BHLHE41, CLOCK, CRY1, CRY2, CSNK1D, CSNK1E, DBP, GSK3B, NPAS2, NR1D1, PER1, PER2, PER3, PPARGC1A, RORA, and RORB. Gene expression networks were analyzed with the disjoint graphs method. Compared to the other investigated transcripts, PPARGC1A was the only one whose expression level was differentially affected in patients who have experienced CM and, more specifically, physical abuse. We observed no significant effects of the other CTQ subscores (emotional and sexual abuses, physical and emotional neglects), nor of the sleep quality on the network of circadian genes expression. Although requiring replication in larger cohorts, the result obtained here is consistent with the hypothesis of an influence of CM exposure on circadian systems and highlights the importance of PPARGC1A in these processes.

Childhood maltreatment and HPA axis gene expression in bipolar disorders: A gene network analysis.

INTRODUCTION: Bipolar disorder (BD) is highly associated with childhood maltreatment (CM), the exposure to such early adversity being suggested to disrupt the expression of several biological pathways. This study aims at exploring associations between the mRNA levels of 9 HPA axis genes in lymphoblastoid cell lines from patients with BD according to their self-reported exposure to CM. METHODS: The sample consisted of 33 Caucasian patients with a diagnosis of BD type 1, assessed for the exposure to CM with the Childhood Trauma Questionnaire (CTQ). Quantitative RT-PCR was performed on 9 transcripts of the HPA axis genes: DGKH, FKBP5, NR3C1, SGK1, SGK2, SGK3, SKA2, STAT5A and UCN. RT-qPCR data were analyzed using the method of disjoint gene networks with SARP.compo package for R. RESULTS: We found no associations between CTQ total score and the amount of HPA axis transcripts neither in univariate analyses, nor with network analyses. Emotional abuse (EA) was associated with a significant decreased expression of two transcripts, DGKH (p = 0.009) and NR3C1 (p = 0.04). This was confirmed by the disjoint network analysis, which showed that NR3C1 and DGKH were expressed differently from the rest of the HPA axis network in presence of emotional abuse. DISCUSSION: This study described the expression levels of a comprehensive set of HPA axis genes according to childhood maltreatment in a sample of patients with BD type 1 and suggested that emotional abuse decreased the expression of NR3C1 and DGKH. Our results require further replication in independent larger samples.

Determinants of the interindividual variability in serum cytidine deaminase activity of patients with solid tumours.

AIMS: Cytidine deaminase (CDA) activity in cancer patients' serum has been proposed as a predictive biomarker for efficacy and toxicity of nucleoside analogues. However, discrepant results about its predictive value have been reported due to the high interindividual variability in CDA activity. This study aimed at identifying determinants of this interindividual variability. METHODS: From December 2014 to November 2015, 183 patients were prospectively included. Serum CDA activity, biological and clinical characteristics as well as five common single nucleotide polymorphisms (SNPs) in the CDA gene (c.-451C > T, c.-92A > G, c.-33_-31delC, c.79A > C, c.435 T > C) were analysed. Associations between clinical characteristics, pharmacogenetic variants and CDA activity were univariately tested. P < 0.1-candidate variables were analysed through a multivariate analysis. The association between CDA activity and toxicity was assessed for the 56 gemcitabine-treated patients. Intraindividual variability in CDA activity was explored in six pancreatic cancer patients treated with gemcitabine. RESULTS: Median CDA activity was 3.97 U mg-1 (range 1.53-15.49 U mg-1 ). A univariate analysis showed that CDA activity was statistically associated with Eastern Cooperative Oncology Group performance status, mild or severe malnutrition, inflammatory syndrome, leucocyte count, neutrophil count, albumin, C-reactive protein and -c.-33_-31delC single nucleotide polymorphism. A multivariate analysis identified that only neutrophil count (P < 0.0001) and severe malnutrition (P = 0.0278) were independently associated with CDA activity. Low CDA activity (<2 U mg-1 ) was not statistically associated with severe gemcitabine-related toxicities (P = 0.16). A decrease in CDA activity was observed during the longitudinal follow-up of six pancreatic cancer patients treated with gemcitabine (P = 0.03). CONCLUSIONS: These results suggest that neutrophil count and malnutrition should be considered for the interpretation of pretherapeutic CDA activity.

Usefulness of monitoring of B cell depletion in rituximab-treated rheumatoid arthritis patients in order to predict clinical relapse: a prospective observational study.

Our objective was to evaluate the contribution of monitoring B cell subset depletion after rituximab in patients with rheumatoid arthritis (RA) in order to guide reintroduction to forestall relapse. This prospective, monocentre study included all RA patients receiving two 1-g rituximab infusions at a 15-day interval. The patients were followed clinically and biologically every 2 months until rituximab reintroduction. The physician was blinded to lymphocyte-typing results to diagnose relapse and, hence, retreatment. Among the 39 patients included between March 2010 and December 2011 and followed until April 2013, seven received two rituximab cycles, yielding a total of 46 cycles for analysis. After the two rituximab cycles, the total number of CD19(+) B cells decreased significantly (0·155 versus 0·0002 G/l, P < 0·0001), with complete depletions in all patients of CD19(+) CD38(++) CD24(++) (transitional) (P < 0·0001) and CD19(+) CD27(+) (memory) B lymphocytes. A significant majority of patients relapsed within the 4 months following repopulation of total B (P = 0·036), B transitional (P = 0·007) and B memory (P = 0·01) lymphocytes. CD19(+) B lymphocyte repopulation preceded clinical RA relapse and enabled its prediction 4 months in advance. Hence, monitoring of CD19(+) B lymphocytes could serve as a tool to predict those relapses.

An in silico model of enterocytic glutamine to citrulline conversion pathway.

Enterocyte is one of the main sites of amino acids metabolism and particularly of the citrulline biosynthesis. Working at the cellular scale and applying ordinary differential equations (ODEs) formalism, we have built a mathematical model of the enterocytic glutamine to citrulline conversion in the fasting state. This model enables us to test different physiopathological scenarios of enzyme activity loss. Results from two different approaches were compared: a standard approach (KA) based on the Michaelis-Menten assumptions and an association-dissociation approach (VH) based on the kinetic mass action law. For both approaches, ODEs system was numerically solved using Mathematica™. In both cases, the model correctly predicts the physiological plasma citrulline steady-state, but the two approaches present clear differences for metabolites of enzymes having a complex mechanism, challenging the validity of the KA approach in such cases. When physiopathological scenarios of enzyme activity loss are simulated, both approaches predict a very sharp transition from the physiological citrulline plasma level to the lack of its production: the concentration profiles of these simulations show a clear threshold of which characteristics vary with the involved enzyme. Moreover, amongst all enzymes included in the model, the ornithine aminotransferase (OAT) shows the highest sensitivity in the system whatever the approach used. This model points out the limits of the Michaelis-Menten approach to model complex enzyme mechanisms. It highlights the key role of OAT in the studied citrulline synthesis pathway and also suggests an order of magnitude about the optimal ratio of enzyme concentrations in this pathway.

Arsenite medicinal use, metabolism, pharmacokinetics and monitoring in human hair.

Acute promyelocytic leukaemia (APL) is a distinctive subtype of acute myeloid leukaemias. Even through this human disease can be treated by the intravenous administration of all-trans retinoic acid (ATRA), 25% of patients typically relapse after the first treatment. In this context, the intravenous administration of APL patients with an aqueous solution of arsenic trioxide has also been demonstrated to be successful despite the established mammalian toxicity of this arsenic compound. Accordingly, the administration of a therapeutic dose of arsenic trioxide has resulted in an improved patient survival in both relapsing as well newly diagnosed APL patients. We present here a mini-review of the medicinal use of arsenite, its mammalian metabolism (with an emphasis on biomethylation pathways), its elimination and pharmacokinetics and the novel application of hair analysis as a biomonitoring material. This mini-review also introduces our own results on the analysis of hair of patients receiving arsenic trioxide therapy. In this work, instead of quantifying arsenic content in bulk hair, we performed longitudinal analysis in order to use hair as a marker of arsenic exposure correlated to a time scale. Taking into account the hair growth rate, the longitudinal analysis of hair is demonstrated to provide a chronological record of the treatment of patients with arsenic trioxide. The small quantity of material to be analysed required the use of Synchrotron radiation based X-ray fluorescence (SXRF) spectroscopy. The hair arsenic content was well correlated with the clinical background of patients and reflected the intake of arsenic trioxide. In particular, the onset of arsenic trioxide therapy and interruptions during therapy were reflected by total arsenic content, which suggested rapid elimination. Another type of experiment, micro-XRF cartography on thin hair slices, allowed us to obtain distribution maps of arsenic, which demonstrated that arsenic is located at the periphery of hair. Micro-XANES spectra recorded at the periphery of hair, suggest that inorganic arsenic is incorporated in hair in its trivalent oxidation state, in agreement with previous results.

Gadolinium acetylacetonate tetraphenyl monoporphyrinate complex and some of its derivatives: EXAFS study and molecular dynamics simulation.

Many attempts to obtain single crystals appropriate for X-ray diffraction analysis of the Ln(tpp)(acac) derivatives (where Ln = Gd or Sm, tpp = tetraphenylporphyrin and acac = acetylacetonate) have failed so far. A suitable way to get structural parameters for these monoporphyrinates is to use extended X-ray absorption fine structure (EXAFS) spectroscopy. We recorded spectra of the monoporphyrins, Ln(tpp)(acac) and Gd(tpyp)(acac) (where tpyp = tetrapyridylporphyrin), and the bisporphyrin GdH(tpyp)2 in the solid state. We particularly focused our structural analysis on Gd(tpp)(acac), applying both molecular modeling and EXAFS, which allowed us to get accurate results about the local environment of the central atom. The Gd3+ ion of the complex at room temperature was found to be bonded to four monoporphyrin nitrogen atoms at an average distance R(Gd-N(av)) = 2.48 A and to three or four oxygen atoms at R(Gd-O(ac,w)) = 2.38 A from an acetylacetonato anion and a water molecule. The presence of the second water molecule in the coordination sphere was barely discernible by EXAFS analysis. Molecular modeling has provided further information about the coordination core geometry of the Gd(tpp)(acac) monoporphyrinate, including a bishydrated coordination sphere. Also, it has enabled the construction of a 3D structural model on which multiple scattering analyses were attempted. Monte Carlo simulation was used to validate the adjustments. EXAFS spectra analysis was carried out on the derivatives, displaying slight distortions in the lanthanide central-atom coordination geometry.

Almost all about citrulline in mammals.

Citrulline (Cit, C6H13N3O3), which is a ubiquitous amino acid in mammals, is strongly related to arginine. Citrulline metabolism in mammals is divided into two fields: free citrulline and citrullinated proteins. Free citrulline metabolism involves three key enzymes: NO synthase (NOS) and ornithine carbamoyltransferase (OCT) which produce citrulline, and argininosuccinate synthetase (ASS) that converts it into argininosuccinate. The tissue distribution of these enzymes distinguishes three "orthogonal" metabolic pathways for citrulline. Firstly, in the liver, citrulline is locally synthesized by OCT and metabolized by ASS for urea production. Secondly, in most of the tissues producing NO, citrulline is recycled into arginine via ASS to increase arginine availability for NO production. Thirdly, citrulline is synthesized in the gut from glutamine (with OCT), released into the blood and converted back into arginine in the kidneys (by ASS); in this pathway, circulating citrulline is in fact a masked form of arginine to avoid liver captation. Each of these pathways has related pathologies and, even more interestingly, citrulline could potentially be used to monitor or treat some of these pathologies. Citrulline has long been administered in the treatment of inherited urea cycle disorders, and recent studies suggest that citrulline may be used to control the production of NO. Recently, citrulline was demonstrated as a potentially useful marker of short bowel function in a wide range of pathologies. One of the most promising research directions deals with the administration of citrulline as a more efficient alternative to arginine, especially against underlying splanchnic sequestration of amino acids. Protein citrullination results from post-translational modification of arginine; that occurs mainly in keratinization-related proteins and myelins, and insufficiencies in this citrullination occur in some auto-immune diseases such as rheumatoid arthritis, psoriasis or multiple sclerosis.

A new model for statistical error analysis in XAS: about the distribution function of the absorption coefficient.

Under some general hypothesis, this paper proposes a theoretical model, showing that a gaussian distribution is generally a good approximation of the experimental distribution of the absorption coefficient. This result is confirmed experimentally by usage of appropriate statistical tests.

Carboplatin and oxaliplatin decomposition in chloride medium, monitored by XAS.

The stability of carboplatin and oxaliplatin aqueous solutions has been studied under different chloride ions concentration and pH conditions. For both compounds, we demonstrate the chloration of the platinum first coordination shell.

XAS applied to pharmaceuticals: drug administration and bioavailability.

We present selected XAS applications, focused towards practical hospital questions of drug administration and bioavailability, where the technique is driven up to its limits of sensitivity. i) XAS was used to study the interactions between the components of parenteral nutrition solutions, in particular zinc and aminoacids, possibly modifying their bioavailability. ii) We studied by EXAFS a series of binary and ternary copper-aminoacid complexes, in view of the development of an efficient oral drug against copper deficiencies in Menkes disease. iii) EXAFS and XANES analysis allowed us to characterise the solution form of a new arsenic containing drug against leukaemia. In parallel to the XAS measurements, we analysed trace elements levels along patients' hairs, using X-ray fluorescence excited by synchrotron radiation. The measurements along the hair allow for a monitoring of essential trace elements during therapy.

Propagation of statistical errors across EXAFS extraction and Fourier filtering.

A statistical model for estimating the error bars on the EXAFS signal is developed. The average can be calculated at the beginning of the analysis, with the estimation of the error bars made directly on the individual measurements; the error bars are then propagated across the EXAFS extraction. Furthermore, this model also allows the estimation of the error bars on the Fourier transformation of the EXAFS signal, and on the filtered EXAFS spectrum after the inverse Fourier transform.