Molecular analysis and experimental virulence of French and North American Escherichia coli neonatal meningitis isolates: identification of a new virulent clone

Phylogenetic relationships, virulence factors, alone and in specific combinations, and virulence in a rat meningitis model were examined among 132 isolates of Escherichia coli neonatal meningitis from France and North America. Isolates belonging to phylogenetic groups A (n=11), D (n=20), and B2 (n=99) had similar high prevalence rates of the siderophores aerobactin and yersiniabactin and the K1 capsule (>/=70%) yet induced different level of experimental bacteremia. Ectochromosomal DNA-like domains involved in blood-brain barrier passage (PAI III(536) [sfa/foc and iroN; 34%]; GimA [ibeA and ptnC; 38%]; PAI II(J96) [hly, cnf1, and hra; 10%]) were restricted to B2 isolates. Among group B2 isolates, representatives of the O45:K1 clonal group (n=30), which lacked these domains, were as able as the archetypal O18:K1 strain C5 to cause meningitis. Molecular epidemiology combined with experimental virulence assays demonstrate that known virulence factors are insufficient to fully explain the pathophysiology of ECNM and to allow for rational search for new virulence factors.     

Factor VIII deficiency not induced by FVIII gene mutation in a female first cousin of two brothers with haemophilia A

In this study, we reinvestigated a 20-year-old woman, the first cousin of two brothers with severe haemophilia A. This patient was previously assumed to be a carrier of haemophilia A due to her FVIII deficiency. We identified a novel FVIII gene mutation in the family and demonstrated that the FVIII deficiency in this female patient did not result from this gene mutation, but was linked to molecular defects in the von Willebrand factor gene.     

Muscle magnetic resonance imaging abnormalities in X‐linked myopathy with excessive autophagy

Introduction: X‐linked myopathy with excessive autophagy (XMEA) is an X‐linked recessive myopathy due to recently reported mutations in the VMA21 gene. Methods: Four men from 2 separate families were studied. The clinical presentation, genetic data, muscle biopsy, and muscle MRI were analyzed. Results: A known VMA21 mutation, c.163+4A>G, and a new mutation, c.163+3A>G, respectively, were found in the 2 families. The clinical course was characterized by onset in childhood and progressive muscle weakness with a limb‐girdle pattern. Muscle biopsy revealed a mild myopathy with an increased number of giant autophagic vacuoles. Whole‐body muscle MRI showed that pelvic girdle and proximal thighs were the most and earliest affected territories, with sparing of rectus femoris muscles. Muscle changes essentially consisted of degenerative fatty replacement. Conclusions: This study highlights a distinctive MRI pattern of muscle involvement, which can be helpful for diagnosis of XMEA, even before muscle biopsy or genetic analysis. Muscle Nerve 52: 673–680, 2015     

Characterization of the Mycovirome of the Phytopathogenic Fungus,Neofusicoccum parvum

Neofusicoccum parvum is a fungal plant-pathogen belonging to the family Botryosphaeriaceae, and is considered one of the most aggressive causal agents of the grapevine trunk disease (GTD) Botryosphaeria dieback. In this study, the mycovirome of a single strain of N. parvum (COLB) was characterized by high throughput sequencing analysis of total RNA and subsequent bioinformatic analyses. Contig annotations, genome completions, and phylogenetic analyses allowed us to describe six novel mycoviruses belonging to four different viral families. The virome is composed of two victoriviruses in the family Totiviridae, one alphaendornavirus in the family Endornaviridae, two mitoviruses in the family Mitoviridae, and one narnavirus belonging to the family Narnaviridae. The presence of the co-infecting viruses was confirmed by sequencing the RT-PCR products generated from total nucleic acids extracted from COLB. This study shows that the mycovirome of a single N. parvum strain is highly diverse and distinct from that previously described in N. parvum strains isolated from grapevines.     

p16INK4A tumor suppressor gene expression and CD3epsilon deficiency but not pre-TCR deficiency inhibit TAL1-linked T-lineage leukemogenesis

Inactivation of the CDKN2 genes that encode the p16^INK4A and p14^ARF proteins occurs in the majority of human T-cell acute lymphoblastic leukemias (T-ALLs). Ectopic expression of TAL1 and LMO1 genes is linked to the development of T-ALL in humans. In TAL1xLMO1 mice, leukemia develops in 100% of mice at 5 months. To identify the molecular events crucial to leukemic transformation, we produced several mouse models. We report here that expression of P16^INK4A in developing TAL1xLMO1 thymocytes blocks leukemogenesis in the majority of the mice, and the leukemias that eventually develop show P16^INK4A loss of expression. Events related to the T-cell receptor ß selection process are thought to be important for leukemic transformation. We show here that the absence of the pT chain only slightly delays the appearance of TAL1xLMO1-induced T-ALL, which indicates a minor role of the pT chain. We also show that the CD3-mediated signal transduction pathway is essential for this transformation process, since the TAL1xLMO1xCD3-deficient mice do not develop T-ALL for up to 1 year.      

Determination of ERCC2 Lys751Gln and GSTP1 Ile105Val gene polymorphisms in colorectal cancer patients: relationships with treatment outcome

INTRODUCTION: Glutathione S-transferase P1 (GSTP1) and excision-repair cross-complementing repair deficiency group 2 protein (ERCC2 or XPD) may modulate the activity of platinum derivatives. The SNPs, Ile105Val for GSTP1 and Lys751Gln for ERCC2, may affect the efficiency of oxaliplatin in patients treated with an oxaliplatin-based regimen for metastatic colorectal carcinoma. PATIENTS & METHODS: A total of 107 patients treated with first-line chemotherapy, 59 with an oxaliplatin-based regimen and 48 with an irinotecan-based regimen, were included retrospectively. GSTP1 and ERCC2 genotypes were identified on DNA samples extracted from paraffin blocks containing either normal tissue (nodes) or tumor tissue. We analyzed treatment response, event-free and overall survival. RESULTS: GSTP1 genotype distribution was Ile/Ile 58%, Ile/Val 35% and Val/Val 7%. ERCC2 genotype distribution was Lys/Lys 49%, Lys/Gln 44%, Gln/Gln 7%. Event-free and overall survivals were not significantly different as a function of the GSTP1 genotype, whatever the treatment received. Event-free survival was significantly different as a function of the ERCC2 genotype only in patients receiving oxaliplatin: patients having at least one variant allele had a shorter median event-free survival (6 months) than those having no variant allele (11.6 months, p = 0.008). This difference was maintained for median overall survival (15.6 vs 25.3 months, p = 0.016). Using univariate analysis, ERCC2 genotype, hemoglobinemia and carbohydrate antigen 19.9 plasma levels were significantly related to overall and event-free survival in patients receiving oxaliplatin. CONCLUSION: The ERCC2 genotype appears as an important predictive factor of the survival of patients treated with oxaliplatin in first-line therapy for metastatic colorectal cancer.     

Emerging drugs for the treatment of soft tissue sarcomas

Soft tissue sarcomas are rare cancers of mesenchymal origin. Recent progress in the understanding of the biology of these rare tumours has enabled the identification of distinct molecular and pathological entities within this heterogenous group of neoplasms, and has paved the way for the development of targeted therapeutics directed against activated kinases. One of the most clear examples is the identification of KIT and platelet-derived growth factor receptor-alpha kinase mutations in gastrointestinal stromal tumours, a subset of sarcomas arising from precursors of the interstitial cells of Cajal in the digestive tract, which led to the development of imatinib, sunitinib and other tyrosine kinase inhibitors for the treatment of solid tumours. This model has become the paradigm of a targeted treatment of solid tumours designed to inhibit the causal alteration in the oncogenesis of these tumours. This review summarises treatment strategies in the context of advanced disease and discusses new compounds being developed for patients with soft tissue sarcomas.     

Oxidative stress and proinflammatory effects of carbon black and titanium dioxide nanoparticles: Role of particle surface area and internalized amount

The ubiquitous presence of nanoparticles (NPs) together with increasing evidence linking them to negative health effects points towards the need to develop the understanding of mechanisms by which they exert toxic effects. This study was designed to investigate the role of surface area and oxidative stress in the cellular effects of two chemically distinct NPs, carbon black (CB) and titanium dioxide (TiO₂), on the bronchial epithelial cell line (16HBE14o-). CB and TiO₂ NPs were taken up by 16HBE cells in a dose-dependent manner and were localized within the endosomes or free in the cytoplasm. Oxidative stress produced inside the cell by NPs was well correlated to the BET surface area and endocytosis of NPs. Contrary to intracellular conditions only CB NPs produced reactive oxygen species (ROS) under abiotic conditions. Exposure of cells to NPs resulted in an increased granulocyte macrophage colony stimulating factor (GM-CSF) mRNA expression and secretion. Inflammatory effects of NPs were dependent on the surface area and were mediated through oxidative stress as they were inhibited by catalase. It can be concluded that NP induced oxidative stress and pro-inflammatory responses are well correlated not only with the BET (Brunauer, Emmett and Teller) surface of the individual NPs but also with the internalized amount of NPs. Differences of even few nanometers in primary particle size lead to significant changes in inflammatory and oxidative stress responses.     

Cancer-induced immunosuppression: IL-18-elicited immunoablative NK cells

During cancer development, a number of regulatory cell subsets and immunosuppressive cytokines subvert adaptive immune responses. Although it has been shown that tumor-derived interleukin (IL)-18 participates in the PD-1-dependent tumor progression in NK cell-controlled cancers, the mechanistic cues underlying this immunosuppression remain unknown. Here, we show that IL-18 converts a subset of Kit(-) (CD11b(-)) into Kit(+) natural killer (NK) cells, which accumulate in all lymphoid organs of tumor bearers and mediate immunoablative functions. Kit(+) NK cells overexpressed B7-H1/PD-L1, a ligand for PD-1. The adoptive transfer of Kit(+) NK cells promoted tumor growth in two pulmonary metastases tumor models and significantly reduced the dendritic and NK cell pools residing in lymphoid organs in a B7-H1-dependent manner. Neutralization of IL-18 by RNA interference in tumors or systemically by IL-18-binding protein dramatically reduced the accumulation of Kit(+)CD11b(-) NK cells in tumor bearers. Together, our findings show that IL-18 produced by tumor cells elicits Kit(+)CD11b(-) NK cells endowed with B7-H1-dependent immunoablative functions in mice.