Altered white matter architecture in BDNF met carriers.

Brain-derived neurotrophic factor (BDNF) modulates the pruning of synaptically silent axonal arbors. The Met allele of the BDNF gene is associated with a reduction in the neurotrophin's activity-dependent release. We used diffusion-weighted imaging to construct structural brain networks for 36 healthy subjects with known BDNF genotypes. Through permutation testing we discovered clear differences in connection strength between subjects carrying the Met allele and those homozygotic for the Val allele. We trained a Gaussian process classifier capable of identifying the subjects' allelic group with 86% accuracy and high predictive value. In Met carriers structural connectivity was greatly increased throughout the forebrain, particularly in connections corresponding to the anterior and superior corona radiata as well as corticothalamic and corticospinal projections from the sensorimotor, premotor, and prefrontal portions of the internal capsule. Interhemispheric connectivity was also increased via the corpus callosum and anterior commissure, and extremely high connectivity values were found between inferior medial frontal polar regions via the anterior forceps. We propose that the decreased availability of BDNF leads to deficits in axonal maintenance in carriers of the Met allele, and that this produces mesoscale changes in white matter architecture.

Epidemiology of Pestivirus infection in wild ungulates of the French South Alps.

Inter-species transmission is often incriminated in the epidemiology of Pestivirus diseases. The purpose of this study was to investigate the prevalence of Pestivirus in some mountain wild ungulates and to determine their role in Pestivirus transmission, as mountain pastures are a place where cohabitations between wild and domestic ungulates are particularly high. Between 2003 and 2007, a longitudinal epidemiological study was carried out on hunted ungulates in the French Hautes-Alpes department. Pestivirus-specific antibodies against p80 protein (also named NS3) common to all Bovine Viral Diarrhea Virus (BVDV) and Border Disease Virus (BDV) were found in 45.9% (95% confidence interval [CI95%]: 40.5-51.3%) of the 343 tested chamois (Rupicapra rupicapra). In addition, mouflons (Ovis gmelinii musimon) were shown for the first time to be strongly infected (61.1%; CI95%: 38.6-83.6) by a Pestivirus. These serological ELISA results were confirmed by comparative virus neutralization tests, performed on seven Pestivirus strains by using 15 seropositive samples. The highest antibody titers were directed against 2 BDV strains (Av and 33s strains), rather than BDV-4, a strain responsible for Pyrenean-chamois epizooties. Virus neutralization tests confirm a BDV circulation in wild ungulates in the French South Alps. However, no Pestivirus RNA was detected by reverse-transcriptase polymerase chain reaction in serum and spleen samples from seronegative animals and no virus was isolated from those samples either. Efforts should be made to improve the protocol in order to be able to isolate and characterize the local strain. Finally, the oldness (age) and femaleness (gender) increase the risk of seroconversion in chamois.