[Management of high-risk pregnancies in a context of maternal antiplatelet alloimmunization: Expert opinion of the French-speaking working group]

INTRODUCTION

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a potentially devastating disease, seen in 1/800-1000 neonates. FNAIT is the most common cause of early-onset isolated severe neonatal thrombocytopenia in maternity wards. A working group on fetomaternal platelet alloimmunization was created in 2017, under the auspices on the French Group of Thrombosis and Hemostasis (GFHT).

OBJECTIVES

The objective was to survey clinical practices for management of high-risk pregnancies in a context of suspected or confirmed FNAIT.

METHODS

Recommendations published by the ICTMG were translated in French, and discussed (Fetal and neonatal alloimmune thrombocytopenia: recommendations for evidence-based practice, an international approach. British J of Haematology, 2019, 185, 549-562).

RESULTS

The study involved centers from France, Switzerland and Belgium: Angers, Besançon, Bordeaux, Brest, Créteil/Clamart, Genève, Grenoble, Liège, Lille, Lyon, Marseille, Nantes, Nîmes, Paris (hôpitaux Necker, Robert Debré et Trousseau), Poitiers, Rennes, Saint-Etienne, Strasbourg, Toulouse, Tours.

CONCLUSIONS

Expert opinion was validated on September 23, 2020 (consensus≥90%).

Management of neonatal thrombocytopenia in a context of maternal antiplatelet alloimmunization: Expert opinion of the French-speaking working group

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a potentially devastating disease, seen in 1/800-1000 neonates. FNAIT is the most common cause of early-onset isolated severe neonatal thrombocytopenia in maternity wards. The most feared complication of this disorder is intracranial hemorrhage, leading to death or neurological sequelae. There is no systematic screening of at-risk pregnancies and FNAIT is often discovered when fetal or neonatal bleeding is observed. A working group on fetomaternal platelet alloimmunization was created in 2017, under the auspices on the French Group of Thrombosis and Hemostasis (GFHT). The first objective of this group was to survey clinical practices for treatment of thrombocytopenic neonates in a context of suspected or confirmed FNAIT.

Absolute cross section for DNA damage induced by low-energy (10 eV) electrons: Experimental refinements and sample characterization by AFM

This work describes multiple experimental improvements for measuring absolute cross sections of DNA damage induced by low-energy electrons in nanometer-thick films in vacuum. Measurements of such cross sections are particularly sensitive to film thickness and uniformity. Using atomic force microscopy in 70% ethanol, we present a novel and effective method to determine plasmid DNA film thickness and uniformity that combines height histograms and force-distance curves. We also investigate film deposition with DNA intercalated with 1,3-diaminopropane (Dap) on tantalum-coated substrates as a convenient and cost-effective alternative to the previously-used graphite substrate. The tantalum substrate permits deposition of films very similar to those formed on graphite. Using these refinements and further optimizations of the experimental procedure, we measure an absolute cross section of (7.4 ± 2.3) × 10^-18 cm² per nucleotide for conformational damage to a 3197 base-pair plasmid, induced by 10 eV electrons, which we believe should be considered as a reference value.

Glacial recharge, salinisation and anthropogenic contamination in the coastal aquifers of Recife (Brazil)

Implying large residence times and complex water origins deep coastal aquifers are of particular interest as they are remarkable markers of climate, water use and land use changes. Over the last decades, the Metropolitan Region of Recife (Brazil) went through extensive environmental changes increasing the pressure on water resources and giving rise to numerous environmental consequences on the coastal groundwater systems. We analysed the groundwater of the deep aquifers Cabo and Beberibe that are increasingly exploited. The processes potentially affecting groundwater residence times and flow paths have been studied using a multi-tracer approach (CFCs, SF6, noble gases, 14C, 2H and 18O). The main findings of these investigations show that: (1) Groundwaters of the Cabo and Beberibe aquifers have long residence times and were recharged about 20,000years ago. (2) Within these old groundwaters we can find palaeo-climate evidences from the last glacial period at the tropics with lower temperatures and dryer conditions than the present climate. (3) Recently, the natural slow dynamic of these groundwater systems was significantly affected by mixing processes with contaminated modern groundwater coming from the shallow unconfined Boa Viagem aquifer. (4) The large exploitation of these aquifers leads to a modification of the flow directions and causes the intrusion through palaeo-channels of saline water probably coming from the Capibaribe River and from the last transgression episodes. These observations indicate that the current exploitation of the Cabo and Beberibe aquifers is unsustainable regarding the long renewal times of these groundwater systems as well as their ongoing contamination and salinisation. The groundwater cycle being much slower than the human development rhythm, it is essential to integrate the magnitude and rapidity of anthropogenic impacts on this extremely slow cycle to the water management concepts.

Groundwater contamination in coastal urban areas: Anthropogenic pressure and natural attenuation processes. Example of Recife (PE State, NE Brazil)

In a context of increasing land use pressure (over-exploitation, surface-water contamination) and repeated droughts, identifying the processes affecting groundwater quality in coastal megacities of the tropical and arid countries will condition their long-term social and environmental sustainability. The present study focuses on the Brazilian Recife Metropolitan Region (RMR), which is a highly urbanized area (3,743,854 inhabitants in 2010) on the Atlantic coast located next to an estuarial zone and overlying a multi-layered sedimentary system featured by a variable sediment texture and organic content. It investigates the contamination and redox status patterns conditioning potential attenuation within the shallow aquifers that constitute the interface between the city and the strategic deeper semi-confined aquifers. These latter are increasingly exploited, leading to high drawdown in potenciometric levels of 20-30m and up to 70m in some high well density places, and potentially connected to the surface through leakage. From a multi-tracer approach (major ions, major gases, δ(11)B, δ(18)O-SO4, δ(34)S-SO4) carried out during two field campaigns in September 2012 and March 2013 (sampling of 19 wells and 3 surface waters), it has been possible to assess the contamination sources and the redox processes. The increasing trend for mineralization from inland to coastal and estuarial wells (from 119 to around 10,000μS/cm) is at first attributed to water-rock interactions combined with natural and human-induced potentiometric gradients. Secondly, along with this trend, one finds an environmental pressure gradient related to sewage and/or surface-channel network impacts (typically depleted δ(11)B within the range of 10-15‰) that are purveyors of chloride, nitrate, ammonium and sulfate. Nitrate, ammonium and sulfate (ranging from 0 to 1.70mmol/L, from 0 to 0,65mmol/L, from 0.03 to 3.91mmol/L respectively are also potentially produced or consumed through various redox processes (pyrite oxidation, denitrification, dissimilatory nitrate reduction to ammonium) within the system, as is apparent within a patchwork of biogeochemical reactors. Furthermore, intensive pumping in the coastal area with its high well density punctually leads to temporary well salinization ([Cl] reaching temporarily 79mmol/L). Our results, summarized as a conceptual scheme based on environmental conditions, is a suitable basis for implementing sustainable management in coastal sedimentary hydrosystems influenced by highly urbanized conditions.

Quercetin induces insulin secretion by direct activation of L-type calcium channels in pancreatic beta cells

BACKGROUND AND PURPOSE

Quercetin is a natural polyphenolic flavonoid that displays anti-diabetic properties in vivo. Its mechanism of action on insulin-secreting beta cells is poorly documented. In this work, we have analysed the effects of quercetin both on insulin secretion and on the intracellular calcium concentration ([Ca(2+)]i) in beta cells, in the absence of any co-stimulating factor.

EXPERIMENTAL APPROACH

Experiments were performed on both INS-1 cell line and rat isolated pancreatic islets. Insulin release was quantified by the homogeneous time-resolved fluorescence method. Variations in [Ca(2+)]i were measured using the ratiometric fluorescent Ca(2+) indicator Fura-2. Ca(2+) channel currents were recorded with the whole-cell patch-clamp technique.

KEY RESULTS

Quercetin concentration-dependently increased insulin secretion and elevated [Ca(2+)]i. These effects were not modified by the SERCA inhibitor thapsigargin (1 μmol·L(-1)), but were nearly abolished by the L-type Ca(2+) channel antagonist nifedipine (1 μmol·L(-1)). Similar to the L-type Ca(2+) channel agonist Bay K 8644, quercetin enhanced the L-type Ca(2+) current by shifting its voltage-dependent activation towards negative potentials, leading to the increase in [Ca(2+)]i and insulin secretion. The effects of quercetin were not inhibited in the presence of a maximally active concentration of Bay K 8644 (1 μmol·L(-1)), with the two drugs having cumulative effects on [Ca(2+)]i.

CONCLUSIONS AND IMPLICATIONS

Taken together, our results show that quercetin stimulates insulin secretion by increasing Ca(2+) influx through an interaction with L-type Ca(2+) channels at a site different from that of Bay K 8644. These data contribute to a better understanding of quercetin's mechanism of action on insulin secretion.

HPA-5 typing discrepancy reveals an Ile503Leu substitution in platelet GPIa (α2 integrin)

BACKGROUND AND OBJECTIVES

In fetal/neonatal thrombocytopenia, maternal alloimmunization is diagnosed by the identification of the maternal alloantibody and the offending paternal antigen inherited by the foetus/neonate. Today, for practical reasons, most laboratories perform platelet genotyping instead of phenotyping. Here, we report the case of a human platelet antigen (HPA)-5 genotype/phenotype discrepancy observed in a mother who delivered a mildly thrombocytopenic newborn.

MATERIALS AND METHODS

Platelet antibody detection and platelet phenotyping were performed using the MAIPA assay; platelet genotypes were determined using BeadChip technology (BioArray), PCR-SSP, PCR-RFLP and sequencing.

RESULTS

Serological investigations revealed the presence of maternal anti-GPIIbIIIa autoantibodies. No alloantibodies were detected. No feto-maternal platelet incompatibility was observed for HPA-1 to -21. The mother and newborn were genotyped as HPA-5aa using BeadChips, but as HPA-5a (weak b) with PCR-SSP and HPA-5ab with PCR-RFLP. Mother's platelets were phenotyped as HPA-5b(+). GPIa exon 13 sequencing confirmed the HPA-5ab genotype of the mother and newborn, and revealed an NM_002203.3:c.1594A>C mutation near the HPA-5 polymorphism (5' side), leading to an I503L amino acid change.

CONCLUSION

Feto-maternal alloimmunization was ruled out: the neonatal thrombocytopenia probably resulted from maternal anti-GPIIbIIIa autoantibodies. This case highlights that platelet typing should be performed using two different methods to avoid false diagnosis.

PRKAR1A and PDE4D mutations cause acrodysostosis but two distinct syndromes with or without GPCR-signaling hormone resistance

CONTEXT

Acrodysostosis is a rare skeletal dysplasia that is associated with multiple resistance to G protein-coupled receptor (GPCR) signaling hormones in a subset of patients. Acrodysostosis is genetically heterogeneous because it results from heterozygous mutations in PRKAR1A or PDE4D, two key actors in the GPCR-cAMP-protein kinase A pathway.

OBJECTIVE

Our objective was to identify the phenotypic features that distinguish the two genotypes causing acrodysostosis.

PATIENTS AND METHODS

Sixteen unrelated patients with acrodysostosis underwent a candidate-gene approach and were investigated for phenotypic features.

RESULTS

All patients had heterozygous de novo mutations. Fourteen patients carried a PRKAR1A mutation (PRKAR1A patients), five each a novel PRKAR1A mutation (p.Q285R, p.G289E, p.A328V, p.R335L, or p.Q372X), nine the reported PRKAR1A p.R368X mutation; two patients harbored a mutation in PDE4D (PDE4D patients) (one novel mutation, p.A227S; one reported, p.E590A). All PRKAR1A, but none of the PDE4D mutated patients were resistant to PTH and TSH. Two PRKAR1A patients each with a novel mutation presented a specific pattern of brachydactyly. One PDE4D patient presented with acroskyphodysplasia. Additional phenotypic differences included mental retardation in PDE4D patients. In addition, we report the presence of pigmented skin lesions in PRKAR1A and PDE4D patients, a feature not yet described in the acrodysostosis entity.

CONCLUSIONS

All PRKAR1A and PDE4D patients present similar bone dysplasia characterizing acrodysostosis. Phenotypic differences, including the presence of resistance to GPCR-cAMP signaling hormones in PRKAR1A but not PDE4D patients, indicate phenotype-genotype correlations and highlight the specific contributions of PRKAR1A and PDE4D in cAMP signaling in different tissues.

Effects of short-chain fructooligosaccharides on growth performance of preruminant veal calves

This study was conducted to evaluate the effects of 2 different daily doses of short-chain fructooligosaccharides (scFOS), a prebiotic ingredient, added to a calf milk replacer on growth performance, carcass characteristics, and fecal concentrations of short-chain fatty acids of preruminant veal calves. In total, 112 male Prim'Holstein calves, between 8 and 10d of age, were randomized in this study according to their body weight and were bred until the age of 168 d. They were fed a calf milk replacer containing 5% soluble wheat proteins as well as cereal-based pellets, the composition of which was adapted to cover the needs of the animals throughout the study. After 2 wk of adaptation, the calf milk replacer was supplemented or not supplemented with a daily dose of 3 or 6g of scFOS. Growth performance of calves, as measured by body weight, cold carcass weight, feed intake, average daily gain, and feed conversion ratio, was recorded and feces samples were taken to evaluate short-chain fatty acid concentrations. The inclusion of wheat proteins in milk replacer did not negatively affect the growth performance of calves in comparison with general standards. The addition of scFOS in the milk reduced the feed conversion ratio of veal calves in a dose-dependent manner and tended to increase the carcass weight. A general trend was observed for an increased production of total short-chain fatty acids in time, but scFOS decreased acetate proportion to the benefit of butyrate proportion. These data suggest that inclusion of scFOS in the calf milk replacer allowed the growth performance of preruminant calves to be enhanced, possibly via a modification of the activities of microbial fermentation.