Mutational spectrum in the cardioauditory syndrome of Jervell and Lange-Nielsen

Jervell and Lange-Nielsen syndrome (JLNS) is an autosomal recessive syndrome characterised by profound congenital sensorineural deafness and prolongation of the QT interval on the electrocardiogram, representing abnormal ventricular repolarisation. In a study of ten British and Norwegian families with JLNS, we have identified all of the mutations in the KCNQ1 gene, including two that are novel. Of the nine mutations identified in this group of 10 families, five are nonsense or frameshift mutations. Truncation of the protein proximal to the recently identified C-terminal assembly domain is expected to preclude assembly of KCNQ1 monomers into tetramers and explains the recessive inheritance of JLNS. However, study of a frameshift mutation, with a dominant effect phenotypically, suggests the presence of another assembly domain nearer to the N-terminus.     

Co-transplantation of human hematopoietic stem cells and human breast cancer cells in NSG mice: A novel approach to generate tumor cell specific human antibodies

Humanized tumor mice (HTM) were generated by the co-transplantation of human hematopoietic stem cells and human breast cancer cells overexpressing HER2 into neonatal NOD-scid IL2Rγ^null (NSG) mice. These mice are characterized by the development of a human immune system in combination with human breast cancer growth. Due to concurrent transplantation into newborn mice, transfer of MHC-mismatched tumor cells resulted in solid coexistence and immune cell activation (CD4⁺ T cells, natural killer cells, and myeloid cells), but without evidence for rejection. Histological staining of the spleen of HTM revealed co-localization of human antigen-presenting cells together with human T and B cells allowing MHC-dependent interaction, and thereby the generation of T cell-dependent antibody production. Here, we investigated the capability of these mice to generate human tumor-specific antibodies and correlated immunoglobulin titers with tumor outgrowth. We found detectable IgM and also IgG amounts in the serum of HTM, which apparently controlled tumor development when IgG serum concentrations were above 10 µg/ml. Western blot analyses revealed that the tumor-specific antibodies generated in HTM did not recognize HER2/neu antigens, but different, possibly relevant antigens for breast cancer therapy. In conclusion, HTM offer a novel approach to generate complete human monoclonal antibodies that do not require further genetic manipulation (e. g., humanization) for a potential application in humans. In addition, efficacy and safety of the generated antibodies can be tested in the same mouse model under human-like conditions. This might be of particular interest for cancer subtypes with no currently available antibody therapy.     

The Influence of Nanocrystal Aggregates on Photovoltaic Performance in Nanocrystal–Polymer Bulk Heterojunction Solar Cells

CdSe nanocrystals (NCs) can be used as an electron acceptor in solar cells, employing organic ligands to passivate their surface and make them processable from solution. The nature and abundance of impurities present after NC ligand exchange from oleic acid to n‐butylamine are identified. A further purification step using hexane as a selective solvent is described, which excludes NC aggregates from solution. The influence of NC aggregates on photovoltaic device performance is studied in a CdSe:poly[2‐methoxy‐5‐(3′,7′‐dimethyloctyloxy)‐1,4‐phenylene vinylene] (MDMO‐PPV) bulk heterojunction solar cell. The exclusion of NC aggregates leads to a four‐fold increase in device power conversion efficiency (PCE) in optimized devices. A superior blend morphology leading to improved charge generation and a better NC percolation network is identified as the main causes of this increased solar cell performance.     

Representative seroprevalences of brucellosis in humans and livestock in Kyrgyzstan

Kyrgyzstan reported 77.5 new human brucellosis cases per 100,000 people in 2007, which is one of the highest incidences worldwide. In Kyrgyzstan, the currently used diagnostic tests in humans and animals are the Rose Bengal Test and the Huddleson test. A national representative cross-sectional study using cluster sampling proportional to size in humans, cattle, sheep, and goats was undertaken to assess the apparent seroprevalence in humans and animals. A total of 4,936 livestock sera and 1,774 human sera were tested in Naryn, Chuy, and Osh Oblasts. The overall apparent seroprevalences of brucellosis were 8.8% in humans (95% CI 4.5-16.5), 2.8% (95% CI 1.6-4.9%) in cattle, 3.3% (95% CI 1.5-6.9%) in sheep, and 2.5% (95% CI 1.4-4.5%) in goats. Naryn Oblast had the highest seroprevalences in humans and sheep. More men than women were seropositive (OR = 1.96; P < 0.001). Human seroprevalence was significantly associated with small ruminant seroprevalence but not with cattle seroprevalence. Annual incidence of human brucellosis exposure, measured by serological tests, was more than ten times higher than the annual incidence of reported clinical brucellosis cases. This indicates an under-reporting of human brucellosis cases, even if only a fraction of seropositive people have clinical symptoms. In conclusion, this study confirms the high seroprevalence of brucellosis in Kyrgyzstan and warrants rapid effective intervention, among others, by mass vaccination of sheep and goats but also of cattle.     

S-Nitroso-N-acetylpenicillamine impregnated endotracheal tubes for prevention of ventilator-associated pneumonia

The chances of ventilator-associated pneumonia (VAP) increases 6–20 folds when an endotracheal tube (ETT) is placed in a patient. VAP is one of the most common hospital-acquired infections and comprises 86% of the nosocomial pneumonia cases. This study introduces the idea of nitric oxide-releasing ETTs (NORel-ETTs) fabricated by the incorporation of the nitric oxide (NO) donor S-nitroso-N-acetylpenicillamine (SNAP) into commercially available ETTs via solvent swelling. The impregnation of SNAP provides NO release over a 7-day period without altering the mechanical properties of the ETT. The NORel-ETTs successfully reduced the bacterial infection from a commonly found pathogen in VAP, Pseudomonas aeruginosa, by 92.72 ± 0.97% when compared with the control ETTs. Overall, this study presents the incorporation of the active release of a bactericidal agent in ETTs as an efficient strategy to prevent the risk of VAP.     

Random epigenetic modulation of CHO cells by repeated knockdown of DNA methyltransferases increases population diversity and enables sorting of cells with higher production capacities

Chinese hamster ovary (CHO) cells produce a large share of today's biopharmaceuticals. Still, the generation of satisfactory producer cell lines is a tedious undertaking. Recently, it was found that CHO cells, when exposed to new environmental conditions, modify their epigenome, suggesting that cells adapt their gene expression pattern to handle new challenges. The major aim of the present study was to employ artificially induced, random changes in the DNA-methylation pattern of CHO cells to diversify cell populations and consequently increase the finding of cell lines with improved cellular characteristics. To achieve this, DNA methyltransferases and/or the ten-eleven translocation enzymes were downregulated by RNA interference over a time span of ∼16 days. Methylation analysis of the resulting cell pools revealed that the knockdown of DNA methyltransferases was highly effective in randomly demethylating the genome. The same approach, when applied to stable CHO producer cells resulted in (a) an increased productivity diversity in the cell population, and (b) a higher number of outliers within the population, which resulted in higher specific productivity and titer in the sorted cells. These findings suggest that epigenetics play a previously underestimated, but actually important role in defining the overall cellular behavior of production clones.     

Comparative Assessment of ELISAs Using Recombinant Saposin-Like Protein 2 and recombinant Cathepsin L-1 from Fasciola hepatica for the Serodiagnosis of Human Fasciolosis

Two recombinant Fasciola hepatica antigens, saposin-like protein-2 (recSAP2) and cathepsin L-1 (recCL1), were assessed individually and in combination in enzyme-linked immunosorbent assays (ELISA) for the specific serodiagnosis of human fasciolosis in areas of low endemicity as encountered in Central Europe. Antibody detection was conducted using ProteinA/ProteinG (PAG) conjugated to alkaline phosphatase. Test characteristics as well as agreement with results from an ELISA using excretory–secretory products (FhES) from adult stage liver flukes was assessed by receiver operator characteristic (ROC) analysis, specificity, sensitivity, Youdens J and overall accuracy. Cross-reactivity was assessed using three different groups of serum samples from healthy individuals (n = 20), patients with other parasitic infections (n = 87) and patients with malignancies (n = 121). The best combined diagnostic results for recombinant antigens were obtained using the recSAP2-ELISA (87% sensitivity, 99% specificity and 97% overall accuracy) employing the threshold (cut-off) to discriminate between positive and negative reactions that maximized Youdens J. The findings showed that recSAP2-ELISA can be used for the routine serodiagnosis of chronic fasciolosis in clinical laboratories; the use of the PAG-conjugate offers the opportunity to employ, for example, rabbit hyperimmune serum for the standardization of positive controls.     

Nilotinib Is More Potent than Imatinib for Treating Plexiform Neurofibroma In Vitro and In Vivo

Plexiform neurofibromas (PNFs) are benign nerve sheath tumors mostly associated with neurofibromatosis type 1. They often extend through multiple layers of tissue and therefore cannot be treated satisfactorily by surgery. Nilotinib is a tyrosine kinase inhibitor used to treat leukemia, with advantages over the prototype imatinib in terms of potency and selectivity towards BCR-ABL, and the DDR, PDGFR, and KIT receptor kinases. In this study, we compared efficacies of the two drugs on cultured cells of PNF in vitro and on xenografted tumor fragments on sciatic nerve of athymic nude mice. Xenografts were monitored weekly using a high resolution ultrasound measurement. Treatment with nilotinib at a daily dose of 100 mg/kg for four weeks led to a reduction of the graft sizes_std by 68_±7% in the 8 treated mice, significantly more than the 33_±8% reduction in the 8 untreated mice (P<0.05) and the 47_±15% in the 7 mice treated with imatinib (P<0.05). The peak plasma nilotinib concentration 6.6_±1.1 µM is within the pharmacological range of clinical application. Imatinib, but not nilotinib significantly hindered body weight increase of the mice and elevated cytotoxicity of mouse spleen cells (P<0.05). Our results suggest that nilotinib may be more potent than imatinib for treating PNFs and may also be better tolerated. Imatinib seems to have some off-target effect in elevating immunity.     

Initiation of mammalian O-mannosylation in vivo is independent of a consensus sequence and controlled by peptide regions within and upstream of the alpha-dystroglycan mucin domain

To reveal insight into the initiation of mammalian O-mannosylation in vivo, recombinant glycosylation probes containing sections of human alpha-dystroglycan (hDG) were expressed in epithelial cell lines. We demonstrate that O-mannosylation within the mucin domain of hDG occurs preferentially at Thr/Ser residues that are flanked by basic amino acids. Protein O-mannosylation is independent of a consensus sequence, but strictly dependent on a peptide region located upstream of the mucin domain. This peptide region cannot be replaced by other N-terminal peptides, however, it is not sufficient to induce O-mannosylation on a structurally distinct mucin domain in hybrid constructs. The presented in vivo evidence for a more complex regulation of mammalian O-mannosylation contrasts with a recent in vitro study of O-mannosylation in human alpha-dystroglycan peptides indicating the existence of an 18-meric consensus sequence. We demonstrate in vivo that the entire region p377-417 is necessary and sufficient for O-mannosylation initiation of hDG, but not of MUC1 tandem repeats. The feature of a doubly controlled initiation process distinguishes mammalian O-mannosylation from other types of O-glycosylation, which are largely controlled by structural properties of the substrate positions and their local peptide environment.