Pathologic and Phenotypic Alterations in a Mouse Expressing a Connexin47 Missense Mutation That Causes Pelizaeus-Merzbacher–Like Disease in Humans

Gap junction channels are intercellular conduits that allow diffusional exchange of ions, second messengers, and metabolites. Human oligodendrocytes express the gap junction protein connexin47 (Cx47), which is encoded by the GJC2 gene. The autosomal recessive mutation hCx47M283T causes Pelizaeus-Merzbacher–like disease 1 (PMLD1), a progressive leukodystrophy characterized by hypomyelination, retarded motor development, nystagmus, and spasticity. We introduced the human missense mutation into the orthologous position of the mouse Gjc2 gene and inserted the mCx47M282T coding sequence into the mouse genome via homologous recombination in embryonic stem cells. Three-week-old homozygous Cx47M282T mice displayed impaired rotarod performance but unchanged open-field behavior. 10-15-day-old homozygous Cx47M282T and Cx47 null mice revealed a more than 80% reduction in the number of cells participating in glial networks after biocytin injections into oligodendrocytes in sections of corpus callosum. Homozygous expression of mCx47M282T resulted in reduced MBP expression and astrogliosis in the cerebellum of ten-day-old mice which could also be detected in Cx47 null mice of the same age. Three-month-old homozygous Cx47M282T mice exhibited neither altered open-field behavior nor impaired rotarod performance anymore. Adult mCx47M282T expressing mice did not show substantial myelin alterations, but homozygous Cx47M282T mice, additionally deprived of connexin32, which is also expressed in oligodendrocytes, died within six weeks after birth and displayed severe myelin defects accompanied by astrogliosis and activated microglia. These results strongly suggest that PMLD1 is caused by the loss of Cx47 channel function that results in impaired panglial coupling in white matter tissue

Correlations of differentially expressed gap junction connexins cx26, cx30, cx32, cx43 and cx46 with breast cancer progression and prognosis.

BACKGROUND AND AIMS: Connexins and their cell membrane channels contribute to the control of cell proliferation and compartmental functions in breast glands and their deregulation is linked to breast carcinogenesis. Our aim was to correlate connexin expression with tumor progression and prognosis in primary breast cancers. MATERIALS AND METHODS: Meta-analysis of connexin isotype expression data of 1809 and 1899 breast cancers from the Affymetrix and Illumina array platforms, respectively, was performed. Expressed connexins were also monitored at the protein level in tissue microarrays of 127 patients equally representing all tumor grades, using immunofluorescence and multilayer, multichannel digital microscopy. Prognostic correlations were plotted in Kaplan-Meier curves and tested using the log-rank test and cox-regression analysis in univariate and multivariate models. RESULTS: The expression of GJA1/Cx43, GJA3/Cx46 and GJB2/Cx26 and, for the first time, GJA6/Cx30 and GJB1/Cx32 was revealed both in normal human mammary glands and breast carcinomas. Within their subfamilies these connexins can form homo- and heterocellular epithelial channels. In cancer, the array datasets cross-validated each other's prognostic results. In line with the significant correlations found at mRNA level, elevated Cx43 protein levels were linked with significantly improved breast cancer outcome, offering Cx43 protein detection as an independent prognostic marker stronger than vascular invasion or necrosis. As a contrary, elevated Cx30 mRNA and protein levels were associated with a reduced disease outcome offering Cx30 protein detection as an independent prognostic marker outperforming mitotic index and necrosis. Elevated versus low Cx43 protein levels allowed the stratification of grade 2 tumors into good and poor relapse free survival subgroups, respectively. Also, elevated versus low Cx30 levels stratified grade 3 patients into poor and good overall survival subgroups, respectively. CONCLUSION: Differential expression of Cx43 and Cx30 may serve as potential positive and negative prognostic markers, respectively, for a clinically relevant stratification of breast cancers

Wireless technologies for the construction sector—Requirements, energy and cost efficiencies

The construction sector has been rather reluctant with respect to the implementation of ITC innovations that other industries have adopted for years. One of the reasons could be the lack of services by the proposed innovations especially the RFID solutions. This technology is well‐researched within the building sector and is therefore used to analyse requirements for alternative technologies. The motivationof the current work is to find upcoming technologies that bring improvements into the sector, for example improved life cycle costs and energy efficiencies, increasing quality, construction and operation efficiency and reducing faults and losses.The paper also lays out requirements expected by the sector. It will be shown that the wireless sensor network technology is a strong competitor that may meet the requirements. By analysing the application of such technologies throughout the building lifecycle, the utilization can be manifold, hereby minimising overall economic costs and maximising the added values for all involved stakeholders.Based on the expectations of the sector, the experiences with the introduction of the RFID technology and by estimating the applicability of the extra services that follow the wireless sensor network, the paper will line up the requirements that the new technology has to meet to be introduced successfully

Space-borne high resolution fire remote sensing in Benin

An experiment on high resolution remote sensing of fires was conducted in the Oue´me´ catchment area of Benin, West Africa using the Bi-spectral InfraRed Detection (BIRD) satellite. The high spatial resolution capability of the BIRD system allows the detection of fires with active burning areas less than a few hundred square metres in the sub-pixel domain, as well as the estimation of quantitative characteristics of these fires, such as the radiative fire energy release and (less accurately) the effective fire temperature and area

Impact of membrane properties on uptake and transcytosis of colloidal nanocarriers across an epithelial cell barrier model

The aim of this study was to investigate the effect of liposomal membrane properties on cellular uptake and transcytosis across a tight Madin-Darby canine kidney (MDCK) cell barrier in vitro. More than 25 small vesicles were prepared by lipid film hydration/extrusion to generate small unilamellar vesicles. The fluorescence marker calcein was encapsulated to mimic hydrophilic drug transport. Marker uptake by MDCK cells seems to be mediated by different mechanisms for the liposomes used. It was mainly depending on membrane fluidity and vesicle charge. Liposomes L2 with a positive charge (325 +/- 3 pmol/well) and vesicles L3 containing the helper lipid dioleylphosphatidylethanolamine (DOPE) in their membrane (216 +/- 42 pmol/well) were taken up to the most. Selected liposomes were tested for their transcytotic transport across a MDCK monolayer. Liposomes L4 containing equimolar DOPE and octadecyl-1,1-dimethylpiperidin-1-ium-4-yl phosphate (OPP) were the most efficient vesicles for transcellular transport resulting in 808 +/- 30 pmol calcein/cm(2) in the basal medium (28.1% of total liposomal marker added). Transcytosis was positively correlated with membrane fluidity in the outer part of the bilayer, as electron paramagnetic resonance measurements revealed. We expect that an increase in membrane fluidity of vesicles should also improve the restricted transport of hydrophilic drugs across the blood-brain barrier