Identification of prognostic markers in diffuse midline gliomas H3K27M‐mutant

Pediatric diffuse midline gliomas are devastating diseases. Among them, diffuse midline gliomas H3K27M‐mutant are associated with worse prognosis. However, recent studies have highlighted significant differences in clinical behavior and biological alterations within this specific subgroup. In this context, simple markers are needed to refine the prognosis of diffuse midline gliomas H3K27M‐mutant and guide the clinical management of patients. The aims of this study were (i) to describe the molecular, immunohistochemical and, especially, chromosomal features of a cohort of diffuse midline gliomas and (ii) to focus on H3K27M‐mutant tumors to identify new prognostic markers. Patients were retrospectively selected from 2001 to 2017. Tumor samples were analyzed by immunohistochemistry (including H3K27me3, EGFR, c‐MET and p53), next‐generation sequencing and comparative genomic hybridization array. Forty‐nine patients were included in the study. The median age at diagnosis was 9 years, and the median overall survival (OS) was 9.4 months. H3F3A or HIST1H3B mutations were identified in 80% of the samples. Within the H3K27M‐mutant tumors, PDGFRA amplification, loss of 17p and a complex chromosomal profile were significantly associated with worse survival. Three prognostic markers were identified in diffuse midline gliomas H3K27M‐mutant: PDGFRA amplification, loss of 17p and a complex chromosomal profile. These markers are easy to detect in daily practice and should be considered to refine the prognosis of this entity.     

Emergence of extended-spectrum-beta-lactamase (CTX-M-9)-producing multiresistant strains of Salmonella enterica serotype Virchow in poultry and humans in France

During 2002 to 2003, eight Salmonella enterica serotype Virchow poultry and poultry product isolates from various sources (chicken farms, poultry slaughterhouse, or retail store) and one S. enterica rough strain isolated from human feces were found to produce extended-spectrum beta-lactamase CTX-M-9. Poultry and poultry product isolates were recovered from different locations in the southwest of France. The human rough isolate had sequences of flagellin genes (fliC and fljB) typical of serotype Virchow and ribotyping and pulsed-field gel electrophoresis (PFGE) patterns closely similar to those of serotype Virchow strains. PFGE confirmed the clonal relationship between the poultry isolates, while the human isolate displayed a pattern with 94% homology. The bla(CTX-M-9) gene was located on a conjugative plasmid and was shown to be linked to orf513. Plasmid profiling found a very similar EcoRI restriction pattern in six transconjugants studied, including transconjugants obtained from the human isolate. A single hatchery, supplying chicks to the six farms, was identified. Emergence of extended-spectrum beta-lactamase-producing S. enterica strains in food animals is a major concern, as such strains could disseminate on a large scale and lead to antibiotic therapy difficulties.     

Comparative Three‐Dimensional Structure of the Trabecular Bone in the Talus of Primates and Its Relationship to Ankle Joint Loads Generated During Locomotion

The trabecular structure of the ankle bone in small to medium‐bodied (60–5000 g) primates of distinct locomotor types was analyzed using high‐resolution X‐ray computed tomography. There are large inter‐, intraspecific, and regional (medial vs. lateral) variations in the trabecular architecture of the talar body. Body mass has no effect on the bone volume fraction or on the fabric anisotropy. However, both the number and thickness of trabeculae seem to be body mass‐dependent. All taxa show anisotropic trabecular bone, but the degree of anisotropy and elongation values vary, notably across the locomotion categories. The fabric orientation in the talar body indicates that, practically, all taxa studied display a generally consistent pattern of orientation restricted primarily to a dorsoplantar direction. We have observed a mediolateral difference in the bone volume fraction in most primates who are proficient or frequent climbers. This could reflect a specific reinforcement of the trabecular structure in response to the loads engendered in habitually sustained foot inversion. In contrast, tali of primates who are proficient or frequent leapers rather exhibit a different three‐dimensional distribution of the material, which consists of a more anisotropic trabecular structure. This could reflect stronger unidirectional and stereotypical‐loading conditions generated at the ankle joints during a leap. Finally, it appears that the talar trabecular bone structure has a good potential for predicting locomotion in extinct species. We have analyzed the trabecular bone structure of the talus of some Eocene European primates (Adapis, Leptadapis, and Necrolemur) and compared the functional signal of the external versus internal talar anatomy in these fossils. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.     

Multiple retroviral infection by HTLV type 1, 2, 3 and simian foamy virus in a family of Pygmies from Cameroon

To better understand the origins and modes of transmission of HTLV-3 and to search for other retroviral infections (HTLV-1, HTLV-2, foamy viruses), we studied the family of a HTLV-3-infected individual (Pyl43), from Cameroon.Thirty-five persons were included. All adult men were still actively hunting nonhuman primates (NHP). All women were also butchering and cutting-up animals. Five persons reported a bite by an NHP. While HTLV-3 infection was only found in Pyl43, HTLV-1 and HTLV-2 infections were found, respectively, in 5 and 9 persons with one being co-infected by both retroviruses. Phylogenetic analysis suggested intra-familial transmission of HTLV-1 subtypes B and D and HTLV-2. One man was infected by a chimpanzee foamy virus, acquired probably 45 years ago, through a bite. Acquisition of retroviral infections still occurs in central Africa involving to various extent not only intra-familial transmission for HTLV-1/HTLV-2 but also direct interspecies transmission from NHP for foamy virus and possibly for HTLV-1 and HTLV-3.     

Introduction of a novel parechovirus RT-PCR clinical test in a regional medical center

BackgroundHuman enterovirus 71 (EV-71) emerged as a significant pathogen able to cause large outbreaks involving severe neurological cases and children fatalities in Asia.ObjectivesTo describe epidemiology of EV-71 infections in France.Study designFifty-nine patients admitted in 12 different hospitals from 1994 to 2009 were included. The entire VP1 coding gene of 58 EV-71 strains was sequenced and phylogenetic analyses were performed to assign strains to genogroups/subgenogroups and to compare French isolates to European and worldwide isolates.ResultsThe median age of the patients was 1.04 years (9 days to 7 years). Among 46 documented EV-71 infections, 39 were self-limited. Seven children developed severe sepsis-like, respiratory or neurological complications. Among them, 2 children died from acute respiratory distress syndrome. All the EV-71 strains belonged to genogroup C: 31 isolates belonged to subgenogroup C1, 26 to subgenogroup C2 and 1 to subgenogroup C4. All the strains were genetically related to other European strains isolated at the same period of time. Although C1 isolates were predominant between 1994 and 2005, C2 strains have been predominant since 2007. No association was found between any genotype and the age or the clinical symptoms.ConclusionsThe C4 subgenogroup, which was associated with large outbreaks in China, did not spread in France. It is important to monitor more carefully the EV-71 strains circulating in France to detect the introduction of new genetic variants that could be associated with major outbreaks.     

Identification and functional analysis of SOX10 missense mutations in different subtypes of Waardenburg syndrome

Waardenburg syndrome (WS) is a rare disorder characterized by pigmentation defects and sensorineural deafness, classified into four clinical subtypes, WS1-S4. Whereas the absence of additional features characterizes WS2, association with Hirschsprung disease defines WS4. WS is genetically heterogeneous, with six genes already identified, including SOX10. About 50 heterozygous SOX10 mutations have been described in patients presenting with WS2 or WS4, with or without myelination defects of the peripheral and central nervous system (PCWH, Peripheral demyelinating neuropathy-Central dysmyelinating leukodystrophy-Waardenburg syndrome-Hirschsprung disease, or PCW, PCWH without HD). The majority are truncating mutations that most often remove the main functional domains of the protein. Only three missense mutations have been thus far reported. In the present study, novel SOX10 missense mutations were found in 11 patients and were examined for effects on SOX10 characteristics and functions. The mutations were associated with various phenotypes, ranging from WS2 to PCWH. All tested mutations were found to be deleterious. Some mutants presented with partial cytoplasmic redistribution, some lost their DNA-binding and/or transactivation capabilities on various tissue-specific target genes. Intriguingly, several mutants were redistributed in nuclear foci. Whether this phenomenon is a cause or a consequence of mutation-associated pathogenicity remains to be determined, but this observation could help to identify new SOX10 modes of action.     

Hydrographic network structure and population genetic differentiation in a vector of fasciolosis,Galba truncatula

We report a preliminary analysis on the relationships between drainage basin structure and genetic structure of populations of the European vector of fasciolosis, Galba truncatula. In the study area, 251 snails belonging to 12 populations were collected along different ditches of a same river network. Each snail was genotyped at six variable microsatellite loci. Our results show that all sample sites are characterized by a low level of polymorphism and a very high and significant heterozygote deficiency. Our data reveal a significant genetic differentiation, even at a small scale, and failed to delimit clear patterns of isolation by euclidian distance. Our study shows that genetic differentiation significantly increases with hydrographic distance along the streams (p < 0.002), in consistence with the hypothesis that dispersion along the stream is dependent on the direction of water flow. This study shows that relationships can exist between the organization of the hydrological network and population biology of a disease vector, which has strong potential applications to drainage network management issues.     

Hypothalamic A14 and A15 catecholamine cells provide the dopaminergic innervation to the supraoptic nucleus in rat: a combined retrograde tracer and immunohistochemical study.

This study investigated the origin of a dopaminergic innervation of the hypothalamic supraoptic nucleus. In pentobarbital-anaesthetized male Long-Evans rats, a transpharyngeal approach was used to inject a retrograde tracer, rhodamine latex microspheres, into the supraoptic nucleus. After 13-26 h survival under anaesthesia, animals were perfused transcardially, the brain sectioned and processed for tyrosine hydroxylase immunofluorescence, a marker for hypothalamic dopaminergic neurons. In six cases with injections restricted to the supraoptic nucleus, rhodamine-labelled microspheres were observed in a population of tyrosine hydroxylase-positive neurons located in the A15 cells below the anterior commissure (A15 dorsal) and above the optic chiasm (A15 ventral), and the dorsal and lateral periventricular A14 cell group. Occasional double-labelled cells were seen in the medial and lateral hypothalamus and bed nucleus of the stria terminalis, but rarely in other known dopaminergic cell groups, notably the ventral tegmental area (A10), zona incerta (A13) and substantia nigra. In support of a role for dopamine in neurohypophysial regulation, these observations indicate that the major dopaminergic input to magnocellular neurons in the hypothalamic supraoptic nucleus is derived from a relatively sparse population of neurons located in the A14 and A15 cell groups.     

Remodelling of the SUR–Kir6.2 interface of the KATP channel upon ATP binding revealed by the conformational blocker rhodamine 123

ATP-sensitive K⁺ channels (K_ATP channels) are metabolic sensors formed by association of a K⁺ channel, Kir6, and an ATP-binding cassette (ABC) protein, SUR, which allosterically regulates channel gating in response to nucleotides and pharmaceutical openers and blockers. How nucleotide binding to SUR translates into modulation of Kir6 gating remains largely unknown. To address this issue, we have used a novel conformational K_ATP channel inhibitor, rhodamine 123 (Rho123) which targets the Kir6 subunit in a SUR-dependent manner. Rho123 blocked SUR-less Kir6.2 channels with an affinity of ∼1 μ m , regardless of the presence of nucleotides, but it had no effect on channels formed by the association of Kir6.2 and the N-terminal transmembrane domain TMD0 of SUR. Rho123 blocked SUR + Kir6.2 channels with the same affinity as Kir6.2 but this effect was antagonized by ATP. Protection from Rho123 block by ATP was due to direct binding of ATP to SUR and did not entail hydrolysis because it was not mimicked by AMP, did not require Mg²⁺ and was reduced by mutations in the nucleotide-binding domains of SUR. These results suggest that Rho123 binds at the TMD0–Kir6.2 interface and that binding of ATP to SUR triggers a change in the structure of the contact zone between Kir6.2 and domain TMD0 of SUR that causes masking of the Rho123 site on Kir6.2.     

Micropatterned surfaces of PDMS as growth templates for HEK 293 cells

In this paper the easy and reliable preparation of precise micropatterns on PDMS surfaces is described and the growth of HEK 293 cells on those patterns during culture over several days is examined. The first patterning approach described is based on soft-lithography and polyelectrolyte multilayer deposition. Two different soft-lithographic techniques are employed for creating surface patterns of PAH, PSS, untreated and oxidized PDMS. The growth behavior of HEK 293 cells is investigated on all the dual combinations of the four surfaces, and decreasing preference of the cells for the surfaces in the order PAH (–NH₂) > ox-PDMS (–OH) >> PSS (–SO₃ ⁻) > PDMS (–CH₃) is revealed. As the second patterning approach a method is introduced, which allows the deposition of gel droplets in a microarray format utilizing differences in the surface wettability. This concept is new and expected to be very useful for various applications. Finally, a speculative explanation for the different cell spreading behavior is provided considering the interplay between individual cell–surface interactions and a permanent cell tractional force.