The Effect of Nicotine on Reproduction and Attachment of Human Gingival Fibroblasts In Vitro

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142127/1/jper0658.pd

Nicotinamide alone accelerates the conversion of mouse embryonic stem cells into mature neuronal populations.

Vitamin B3 has been shown to play an important role during embryogenesis. Specifically, there is growing evidence that nicotinamide, the biologically active form of vitamin B3, plays a critical role as a morphogen in the differentiation of stem cells to mature cell phenotypes, including those of the central nervous system (CNS). Detailed knowledge of the action of small molecules during neuronal differentiation is not only critical for uncovering mechanisms underlying lineage-specification, but also to establish more effective differentiation protocols to obtain clinically relevant cells for regenerative therapies for neurodegenerative conditions such as Huntington's disease (HD). Thus, this study aimed to investigate the potential of nicotinamide to promote the conversion of stem cells to mature CNS neurons. METHODS: Nicotinamide was applied to differentiating mouse embryonic stem cells (mESC; Sox1GFP knock-in 46C cell line) during their conversion towards a neural fate. Cells were assessed for changes in their proliferation, differentiation and maturation; using immunocytochemistry and morphometric analysis methods. RESULTS: Results presented indicate that 10 mM nicotinamide, when added at the initial stages of differentiation, promoted accelerated progression of ESCs to a neural lineage in adherent monolayer cultures. By 14 days in vitro (DIV), early exposure to nicotinamide was shown to increase the numbers of differentiated βIII-tubulin-positive neurons. Nicotinamide decreased the proportion of pluripotent stem cells, concomitantly increasing numbers of neural progenitors at 4 DIV. These progenitors then underwent rapid conversion to neurons, observed by a reduction in Sox 1 expression and decreased numbers of neural progenitors in the cultures at 14 DIV. Furthermore, GABAergic neurons generated in the presence of nicotinamide showed increased maturity and complexity of neurites at 14 DIV. Therefore, addition of nicotinamide alone caused an accelerated passage of pluripotent cells through lineage specification and further to non-dividing mature neurons. CONCLUSIONS: Our results show that, within an optimal dose range, nicotinamide is able to singly and selectively direct the conversion of embryonic stem cells to mature neurons, and therefore may be a critical factor for normal brain development, thus supporting previous evidence of the fundamental role of vitamins and their metabolites during early CNS development. In addition, nicotinamide may offer a simple effective supplement to enhance the conversion of stem cells to clinically relevant neurons

BAF complex-mediated chromatin relaxation is required for establishment of X chromosome inactivation

The process of epigenetic silencing, while fundamentally important, is not yet completely understood. Here we report a replenishable female mouse embryonic stem cell (mESC) system, Xmas, that allows rapid assessment of X chromosome inactivation (XCI), the epigenetic silencing mechanism of one of the two X chromosomes that enables dosage compensation in female mammals. Through a targeted genetic screen in differentiating Xmas mESCs, we reveal that the BAF complex is required to create nucleosome-depleted regions at promoters on the inactive X chromosome during the earliest stages of establishment of XCI. Without this action gene silencing fails. Xmas mESCs provide a tractable model for screen-based approaches that enable the discovery of unknown facets of the female-specific process of XCI and epigenetic silencing more broadly.Andrew Keniry ... Jose M. Polo ... et al

Interaction of pore size and hydrophobicity/hydrophilicity for improved oxygen and water transport through microporous layers

Microporous layers consisting of different ratios of acetylene black and carbon fibers with either a hydrophobic polytetrafluoroethylene (PTFE) or a hydrophilic perfluorosulfonic acid (PFSA) ionomer binder are investigated with regards to oxygen and water transport in PEMFCs. For that, the materials are characterized by scanning electron microscopy and mercury porosimetry, revealing an increase of porosity and pore sizes for an increasing carbon fiber content. MPLs, coated onto a commercial hydrophobized non-woven gas diffusion layer substrate, are examined in H2/air fuel cell tests under differential-flow conditions at various dry and humid operating conditions. For both hydrophobic and hydrophilic MPLs in the presence of significant amounts of liquid water in the diffusion layer substrate, the materials with larger pore sizes, i.e. higher carbon fiber contents, perform superior at 0.6 V and show the lowest oxygen transport resistance. However, at the same carbon composition, hydrophilic MPLs have a lower performance compared to the corresponding hydrophobic MPLs, which is explained by the capillary pressure barriers for different pore properties. At operating conditions relevant for automotive applications, a performance enhancement of 48% could be achieved for a purely carbon fiber based MPL compared to a commercial reference

Deuteron NMR measurements of order and mobility in the hard segments of a model polyurethane

Pulsed deuteron NMR results are reported for a series of segmented model polyurethanes with monodisperse hard segments containing specifically labeled sites. The hard segments consist of five piperazine rings ( 1-5) separated by carbonyloxytetramethyleneoxycarbonyl spacers; three labeled derivatives are used, with piperazine-d_8 at the 1,5-, 2,4-, and 3-rings. The soft segments are polydisperse poly(tetramethylene oxide) (M_n ≈ 2000). To facilitate interpretation of the polyurethane spectra, measurements are also made on model compounds of the hard segment oligomer, and a model polymer consisting of soft segments chain extended by individual piperazine-d_8 rings. The results indicate that 85% of the hard segments exist in the hard phase, with low mobility at temperatures below 410 K (≈T_m - 10 K). The rest of the hard segments appear to be dispersed in the soft phase, with high mobility at temperatures above 260 K (≈T_g + 60 K). Molecular mobility is much greater at the exterior than the center of hard segments in the hard phase at temperatures between 300 and 410 K. Comparison of changes in molecular mobility and in the storage modulus with temperature (T) shows that (1) as T increases from 200 to 280 K, increase in mobility of the soft phase due to the glass-to-rubber transition and crystallite melting correlates with the 100-fold decrease in modulus in this range, (2) as T increases to 400 K, increase in mobility at the exterior of the hard phase correlates with the gradual decrease in modulus, and (3) at T ≈ 410 K, onset of high mobility at the center of hard segments in the hard phase correlates with the loss of mechanical integrity

Deuteron NMR measurements of order and mobility in the hard segments of a model polyurethane

Pulsed deuteron NMR results are reported for a series of segmented model polyurethanes with monodisperse hard segments containing specifically labeled sites. The hard segments consist of five piperazine rings ( 1-5) separated by carbonyloxytetramethyleneoxycarbonyl spacers; three labeled derivatives are used, with piperazine-d_8 at the 1,5-, 2,4-, and 3-rings. The soft segments are polydisperse poly(tetramethylene oxide) (M_n ≈ 2000). To facilitate interpretation of the polyurethane spectra, measurements are also made on model compounds of the hard segment oligomer, and a model polymer consisting of soft segments chain extended by individual piperazine-d_8 rings. The results indicate that 85% of the hard segments exist in the hard phase, with low mobility at temperatures below 410 K (≈T_m - 10 K). The rest of the hard segments appear to be dispersed in the soft phase, with high mobility at temperatures above 260 K (≈T_g + 60 K). Molecular mobility is much greater at the exterior than the center of hard segments in the hard phase at temperatures between 300 and 410 K. Comparison of changes in molecular mobility and in the storage modulus with temperature (T) shows that (1) as T increases from 200 to 280 K, increase in mobility of the soft phase due to the glass-to-rubber transition and crystallite melting correlates with the 100-fold decrease in modulus in this range, (2) as T increases to 400 K, increase in mobility at the exterior of the hard phase correlates with the gradual decrease in modulus, and (3) at T ≈ 410 K, onset of high mobility at the center of hard segments in the hard phase correlates with the loss of mechanical integrity

Norovirus Surveillance among Callers to Foodborne Illness Complaint Hotline, Minnesota, USA, 2011–2013

Norovirus is the leading cause of foodborne disease in the United States. During October 2011–January 2013, we conducted surveillance for norovirus infection in Minnesota among callers to a complaint-based foodborne illness hotline who reported diarrhea or vomiting. Of 241 complainants tested, 127 (52.7%) were positive for norovirus