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.

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.

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.

EDNRB gene variants and melanoma risk in two southern European populations.

BACKGROUND: EDNRB gene variants were reported to be associated with melanoma risk in French patients, with the S305N variant showing the highest frequency. AIM: To verify the S305N association with melanoma risk in an independent larger French population (378 patients, 389 controls); to investigate the role of EDNRB variants in melanoma risk in an Italian population (133 patients, 118 controls); and to explore the association of CDKN2A or CDK4 mutations with the S305N EDNRB variant in a subgroup of patients (59 French, 12 Italian) with a suspected hereditary predisposition to melanoma (familial melanoma, sporadic multiple primary melanoma or melanoma associated with pancreatic cancer). METHODS: The S305N variant was genotyped in the French population, while the EDNRB gene in the Italian population was entirely sequenced. RESULTS: Overall, there was no significant difference in the frequency of the S305N variant between patients with sporadic melanoma and controls in either the French or the Italian population. However, a significantly higher S305N allele frequency was detected in French patients with a suspected hereditary predisposition to melanoma compared with controls (P = 0.04). In addition, in this subgroup of patients, the S305N allele was also significantly associated with the presence of CDKN2A mutations (P = 0.04). CONCLUSIONS: Our results showed no evidence of association of the S305N EDNRB polymorphism with sporadic melanoma risk in either the French or Italian populations, but there was an indication that EDNRB might be a melanoma-predisposing gene in French patients with a suspected hereditary predisposition to melanoma.

[Management of high-risk pregnancies in a context of maternal antiplatelet alloimmunization: Expert opinion of the French-speaking working group]. / Prise en charge des grossesses à risque dans un contexte d'incompatibilité fœto-maternelle plaquettaire et/ou d'allo-immunisation : avis du groupe d'experts du GFHT (Groupe français d'études sur l'hémostase et la thrombose).

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%).

Human platelet antigen allele frequencies in different Algerian populations.

The frequencies of human platelet antigens (HPAs) vary between different populations and are a major determinant for the prevalence of HPA alloimmunization and its clinically associated entities. No report on HPA prevalence has previously been published for the Algerian populations which are ethnically diverse. The aim of this study was to determine the HPA allele frequencies in Algerian populations and to identify situations of incompatibility possibly leading to alloimmunization. A total of 485 healthy volunteer Algerian blood donors from different regions and representing different ethnic groups were included. HPA genotyping was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and/or polymerase chain reaction-sequence specific primer (PCR-SSP). The HPA-1 allele frequencies were close to the frequencies found in Caucasian populations. The presence of the molecule human leukocyte antigen (HLA)-DRB3*0101 (17.9%) increases the risk of alloimmunization. We observed an increase in the frequency of homozygous HPA-5b, particularly in the population of Annaba (7.61%) and the Mzab population (5.13%). The allele frequency HPA-2b (0.193-0.147) was similar to that seen in Sub-Saharan African populations. The high frequency of homozygotic HPA-2b (Kabyle 5%; Mzab 2.44% and Annaba 2.19%) could increase the risk of alloimmunization. GPIIb A(k) mutation (2614C>A) was found in these populations. This study is the first to report on HPA allele frequencies in Algerian populations. High allele frequencies were observed for HPA-1b (0.209-0.112), HPA-3b (0.411-0.312) and HPA-5b (0.217-0.087), leading to a high risk of alloimmunization in this population, especially the Mzab and the population of Annaba. Our results could have some impact in the diagnosis, prevention and treatment of alloimmune thrombocytopenia.

(Amino)(aryl)carbenes: stable singlet carbenes featuring a spectator substituent.

Several (amino)(aryl)carbenes have been shown to be stable at room temperature in solution and in the solid state. Electroneutrality of the carbene center is ensured by the amino group, which has both pi-donor and final sigma-acceptor electronic character. The aryl group remains a spectator substituent, as shown by single-crystal x-ray analysis and by its chemical behavior. Because only one electron-active substituent is needed, numerous stable carbenes will become accessible, which will open the way for new synthetic developments and applications in various fields.

[Genotyping applied to platelet immunology: when? How? Limits]. / Génotypage en immunologie plaquettaire: quand? Comment? Limites.

Platelet alloantigens named Human Platelet Antigens (HPA) are involved in immune conflicts such as post-transfusion purpura, platelet transfusion refractoriness and neonatal alloimmune thrombocytopenia. Biological diagnosis relies on: (1) detection of alloantibodies; (2) identification of the alloantigen involved in the immune conflict. Since the development of methods based on molecular biology, platelet genotyping is preferred to phenotyping. Today, most of the Platelet Immunology Units use PCR-RFLP or PCR-SSP, and few use real-time PCR. An increasing amount of commercial kits based on new technologies is now available, for example microarrays, fluorescent or coloured microbeads, or a combination of both technologies. However, an increasing number of polymorphisms have been discovered that are responsible for erroneous platelet genotypings. Consequently, it would be of interest to develop alternative technologies based on antigen/antibody interaction instead of DNA.

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.

Effects of dietary crude protein on protein and fat deposition in milk-fed veal calves.

Research on veal calf production has focused on maximizing lean tissue growth. Nevertheless, limited attention has been paid to the evolution of digestive and metabolic utilization of N and energy as calves get older, whereas age at slaughter increases. The objective of this study was to determine the effects of 4 concentrations of dietary crude protein (CP) content on protein and fat deposition and energy utilization in milk-fed calves at 3 stages of fattening using the balance technique combined with heat production measurements in a respiration chamber. At each stage, 16 Prim'Holstein male calves (mean body weight at each stage: 72, 136, and 212 kg) received 4 isocaloric diets with CP contents of 76, 88, 100, and 112% of a reference CP content fixed at 20% during the first stage and 19% during the 2 later stages. After 2 wk of adaptation to their respective diets and housing conditions, the calves were placed for 1 wk in an open-circuit respiration chamber for N and energy balance measurements (first 6 d) and measurement of the fasting heat production (last day). Measurements for a stage were performed over 2 periods of 4 successive weeks. There was no effect of dietary CP on digestibility during the 2 later stages, but the low-protein diet resulted in lower digestibility coefficients for dry matter, organic matter, gross energy, CP, and crude fat during the first stage. Endogenous fecal N was estimated as 2.5 g/kg of dry matter intake irrespective of stage, and metabolic urinary N was estimated at 0.07 g/kg of body weight(0.85) per day. Maximum N retention was 32.8, 40.5, and 44.0 g/d at stages 1, 2, and 3, respectively. The effect of protein intake on protein deposition was dependent on age of the calves, because the marginal efficiency of digestible protein utilization decreased from 64 to 18% as animals got older. Fat deposition decreased with increasing dietary CP content irrespective of stage. Total energy retention was not modified by dietary CP content. The composition of body weight gain was affected differently for each stage, because the protein content of body weight gain increased with increasing dietary CP content during the first stage, whereas it remained constant during the other 2 stages. Fat and energy content in body weight gain decreased with increasing dietary CP irrespective of stage. These results provide a basis for estimating protein requirement of veal calves according to a factorial approach.

Contribution of 3D printing to mandibular reconstruction after cancer.

Three-dimensional (3D) printing is booming in the medical field. This technology increases the possibilities of personalized treatment for patients, while lowering manufacturing costs. To facilitate mandibular reconstruction with fibula free flap, some companies propose cutting guides obtained by CT-guided moulding. However, these guides are prohibitively expensive (€2,000 to €6,000). Based on a partnership with the CNRS, engineering students and a biomedical company, the authors have developed cutting guides and 3D-printed mandible templates, deliverable in 7days and at a lower cost. The novelty of this project is the speed of product development at a significantly lower price. In this technical note, the authors describe the logistic chain of production of mandible templates and cutting guides, as well as the results obtained. The goal is to allow access to this technology to all patients in the near future.

Non-invasive, transdermal, path-selective and specific glucose monitoring via a graphene-based platform.

Currently, there is no available needle-free approach for diabetics to monitor glucose levels in the interstitial fluid. Here, we report a path-selective, non-invasive, transdermal glucose monitoring system based on a miniaturized pixel array platform (realized either by graphene-based thin-film technology, or screen-printing). The system samples glucose from the interstitial fluid via electroosmotic extraction through individual, privileged, follicular pathways in the skin, accessible via the pixels of the array. A proof of principle using mammalian skin ex vivo is demonstrated for specific and 'quantized' glucose extraction/detection via follicular pathways, and across the hypo- to hyper-glycaemic range in humans. Furthermore, the quantification of follicular and non-follicular glucose extraction fluxes is clearly shown. In vivo continuous monitoring of interstitial fluid-borne glucose with the pixel array was able to track blood sugar in healthy human subjects. This approach paves the way to clinically relevant glucose detection in diabetics without the need for invasive, finger-stick blood sampling.

PAC1 receptor-deficient mice display impaired insulinotropic response to glucose and reduced glucose tolerance.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a ubiquitous neuropeptide of the vasoactive intestinal peptide (VIP) family that potentiates glucose-stimulated insulin secretion. Pancreatic beta cells express two PACAP receptor subtypes, a PACAP-preferring (PAC1) and a VIP-shared (VPAC2) receptor. We have applied a gene targeting approach to create a mouse lacking the PAC1 receptor (PAC1(-/-)). These mice were viable and normoglycemic, but exhibited a slight feeding hyperinsulinemia. In vitro, in the isolated perfused pancreas, the insulin secretory response to PACAP was reduced by 50% in PAC1(-/-) mice, whereas the response to VIP was unaffected. In vivo, the insulinotropic action of PACAP was also acutely reduced, and the peptide induced impairment of glucose tolerance after an intravenous glucose injection. This demonstrates that PAC1 receptor is involved in the insulinotropic action of the peptide. Moreover, PAC1(-/-) mice exhibited reduced glucose-stimulated insulin secretion in vitro and in vivo, showing that the PAC1 receptor is required to maintain normal insulin secretory responsiveness to glucose. The defective insulinotropic action of glucose was associated with marked glucose intolerance after both intravenous and gastric glucose administration. Thus, these results are consistent with a physiological role for the PAC1 receptor in glucose homeostasis, notably during food intake.

Balanced Ambipolar Organic Field-Effect Transistors by Polymer Preaggregation.

Ambipolar organic field-effect transistors (OFETs) based on heterojunction active films still suffer from an imbalance in the transport of electrons and holes. This problem is related to an uncontrolled phase separation between the donor and acceptor organic semiconductors in the thin films. In this work, we have developed a concept to improve the phase separation in heterojunction transistors to enhance their ambipolar performance. This concept is based on preaggregation of the donor polymer, in this case poly(3-hexylthiophene) (P3HT), before solution mixing with the small-molecular-weight acceptor, phenyl-C61-butyric acid methyl ester (PCBM). The resulting heterojunction transistor morphology consists of self-assembled P3HT fibers embedded in a PCBM matrix, ensuring balanced mobilities reaching 0.01 cm2/V s for both holes and electrons. These are the highest mobility values reported so far for ambipolar OFETs based on P3HT/PCBM blends. Preaggregation of the conjugated polymer before fabricating binary blends can be regarded as a general concept for a wider range of semiconducting systems applicable in organic electronic devices.

Predictive value of sequential maternal anti-HPA-1a antibody concentrations for the severity of fetal alloimmune thrombocytopenia.

BACKGROUND: Fetal/neonatal alloimmune thrombocytopenia results from maternal immunization against fetal platelet alloantigens (HPAs), and the major risk is intracranial hemorrhage. The severity of thrombocytopenia increases in subsequent pregnancies, and antenatal therapy has been developed. Until now, the fetal status can only be assessed by fetal blood sampling, which carries a risk of fetal loss or premature delivery. OBJECTIVES: To develop non-invasive methods to gain information on the fetal condition. PATIENTS/METHODS: Quantification of the maternal anti-HPA-1a alloantibody concentration was performed with a standardized monoclonal antibody-specific immobilization of platelet antigens (MAIPA) procedure for 43 mothers. A correlation between this concentration and the fetal/neonatal platelet counts was studied. RESULTS: (i) Before antenatal therapy, there was a significant correlation between maternal anti-HPA-1a concentrations > or =250 AU mL(-1) and fetal thrombocytopenia (2-66 x 10(9) L(-1)) whatever the gestational age (Fisher's exact test P = 0.0021). (ii) During subsequent pregnancies, we observed a decrease of the maternal anti-HPA-1a concentration for 14/19 women. Just before delivery, all women had anti-HPA-1a concentrations <250 AU mL(-1). In four cases, there was a therapy failure and the severely thrombocytopenic babies required postnatal therapy. CONCLUSION: The maternal anti-HPA-1a concentration could provide obstetricians with clinically useful information concerning the appropriateness and the timing of invasive monitoring procedures. However, though we observed a tendency toward a decrease in maternal antibody concentration after treatment, this finding does not allow us to draw any conclusions on the effectiveness of therapy.

Giant cell arteritis and spinal cord compression: an overlap syndrome?

We describe 2 patients with spinal cord compression that occurred in the course of biopsy-proven giant cell arteritis (GCA). One case was due to an epidural tumorlike inflammatory lesion, the other to a concentric inflammatory thickening of the meninges. Both patients were highly corticodependent; they had low-titer anti-neutrophil cytoplasmic antibodies but no antimyeloperoxidase or antiproteinase 3 autoantibodies. The diagnosis was established by surgical biopsy. The histological pattern was reminiscent of Wegener granulomatosis. Both patients experienced relapse, despite high doses of corticosteroids, and experienced remission after the introduction of cyclophosphamide. Intravenous immunoglobulin perfusions were added for 1 patient. To our knowledge, spinal cord compression by a spinal pseudotumor or inflammatory meningitis has not been reported in the course of GCA. An overlap syndrome between GCA and Wegener granulomatosis is discussed.

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.

The quest for the shortest fragments of A (13-19) and B (12-17) responsible for the aggregation of human insulin.

AIM: To identify the shortest components of A13-A19, B12-B17 fragments capable for fibrillation and to validate the dependability of aggregation on the presence of hydroxyl group engaged in the 'tyrosine kissing'. MATERIALS & METHODS: Fragments A13-A19 and B12-B17 of insulin and all shortened analogues were obtained by using DMT/NMM/TosO(-) as a coupling reagent. The aggregation was studied by three independent tests. RESULTS: Studies on the susceptibility to aggregation of truncated analogs of insulin amyloidogenic core show three groups of peptides. CONCLUSION: Truncation of A13-A419 fragment shows that fibrous structures are formed by all peptides bearing (13)H-LeuTyr-OH(14). Propensity to aggregation was found for (16)H-TyrLeu-OH(17) B12-B17 fragment. Tyrosine residue modification by incorporation of tert-butyl group on hydroxyl function gave analogues still predisposed to aggregation.