Sucrose consumption increases naloxone-induced c-Fos immunoreactivity in limbic forebrain

Opioids have long been known to have an important role in feeding behavior, particularly related to the rewarding aspects of food. Considerable behavioral evidence suggests that sucrose consumption induces endogenous opioid release, affecting feeding behavior as well as other opioid-mediated behaviors, such as analgesia, dependence, and withdrawal. In the present study, rats were given access to a 10% sucrose solution or water for 3 wk, then they were injected with 10 mg/kg naloxone or saline. Brains were subsequently analyzed for c-Fos immunoreactivity (c-Fos-IR) in limbic and autonomic regions in the forebrain and hindbrain. Main effects of sucrose consumption or naloxone injection were seen in several areas, but a significant interaction was seen only in the central nucleus of the amygdala and in the lateral division of the periaqueductal gray. In the central nucleus of the amygdala, naloxone administration to those rats drinking water significantly increased c-Fos-IR, an effect that was significantly enhanced by sucrose consumption, suggesting an upregulation of endogenous opioid tone in this area. The data from this study indicate that the central nucleus of the amygdala has a key role in the integration of gustatory, hedonic, and autonomic signals as they relate to sucrose consumption, if not to food intake regulation in general. Furthermore, the data from this study lend further support to the hypothesis that sucrose consumption induces the release of endogenous opioids.     

N-acetylcysteine protects dental pulp stromal cells from HEMA-induced apoptosis by inducing differentiation of the cells

Resin-based materials are now widely used in dental restorations. Although the use of these materials is aesthetically appealing to patients, it carries the risk of local and systemic adverse effects. The potential risks are direct damage to the cells and induction of immune-based hypersensitivity reactions. Dental pulp stromal cells (DPSCs) and oral keratinocytes are the major cell types which may come in contact with dental resins such as 2-hydroxyethyl methacrylate (HEMA) after dental restorations. Here we show that N-acetylcysteine (NAC) inhibits HEMA-induced apoptotic cell death and restores the function of DPSCs and oral epithelial cells. NAC inhibits HEMA-mediated toxicity through induction of differentiation in DPSCs, because the genes for dentin sialoprotein, osteopontin (OPN), osteocalcin, and alkaline phosphatase, which are induced during differentiation, are also induced by NAC. Unlike NAC, vitamins E and C, which are known antioxidant compounds, failed to prevent either HEMA-mediated cell death or the decrease in VEGF secretion by human DPSCs. More importantly, when added either alone or in combination with HEMA, vitamin E and vitamin C did not increase the gene expression for OPN, and in addition vitamin E inhibited the protective effect of NAC on DPSCs. NAC inhibited the HEMA-mediated decrease in NF-kappaB activity, thus providing a survival mechanism for the cells. Overall, the studies reported in this paper indicate that undifferentiated DPSCs have exquisite sensitivity to HEMA-induced cell death, and their differentiation in response to NAC resulted in an increased NF-kappaB activity, which might have provided the basis for their increased protection from HEMA-mediated functional loss and cell death.     

Absolute configuration of (+)-α-dihydrotetrabenazine,an active metabolite of tetrabenazine

Chiral column liquid chromatography and enantiospecific enzymatic hydrolysis were utilized to separate the enantiomers of α- and β-dihydrotetrabenazine and α-9-O-desmethyldihydrotetrabenazine, three benzo[a]quinolizines derived from the amine-depleting drug tetrabenazine. An X-ray crystal structure analysis of (−)-α-9-O-desmethyldihydrotetrabenazine gave an absolute structure of that compound as the 2S, 3S, 11bS isomer. Therefore, (−)-α-dihydrotetrabenazine also has the 2S, 3S, 11bS absolute configuration. (+)-α-Dihydrotetrabenazine, the single biologically active isomer from the metabolic reduction of tetrabenazine, thus has the absolute configuration of 2R, 3R, 11bR. For further in vitro and in vivo studies of the vesicular monoamine transporter, it is now possible to use the single enantiomer of radiolabeled α-dihydrotetrabenazine. Chirality 9:59–62, 1997. © 1997 Wiley-Liss, Inc.     

The Second Recorded Living Coelacanth from North Sulawesi

A detailed account of the second coelacanth specimen known to have been captured in Indonesian waters is provided. The account is written in the official format of the Coelacanth Conservation Council's (CCC) inventory of known specimens of the living coelacanth Latimeria chalumnae, and the specimen is herein numbered CCC no. 175. Morphological measurements and fin ray counts are recorded. A comparison of these measurements and meristic data with those recorded for Comoran specimens of Latimeria chalumnae shows that the present specimen has a similar allometry to L. chalumnae. Ongoing genetic analyses should reveal the depth of divergence between the two known populations of living coelacanths and help determine if this specimen is conspecific with its Comoran counterparts.     

Cell-free synthetic biology: thinking outside the cell

Cell-free synthetic biology is emerging as a powerful approach aimed to understand, harness, and expand the capabilities of natural biological systems without using intact cells. Cell-free systems bypass cell walls and remove genetic regulation to enable direct access to the inner workings of the cell. The unprecedented level of control and freedom of design, relative to in vivo systems, has inspired the rapid development of engineering foundations for cell-free systems in recent years. These efforts have led to programmed circuits, spatially organized pathways, co-activated catalytic ensembles, rational optimization of synthetic multi-enzyme pathways, and linear scalability from the micro-liter to the 100-liter scale. It is now clear that cell-free systems offer a versatile test-bed for understanding why nature's designs work the way they do and also for enabling biosynthetic routes to novel chemicals, sustainable fuels, and new classes of tunable materials. While challenges remain, the emergence of cell-free systems is poised to open the way to novel products that until now have been impractical, if not impossible, to produce by other means.     

Proteins regulating cap-dependent translation are downregulated during total knee arthroplasty

Total knee arthroplasty (TKA) utilizes a tourniquet to reduce blood loss, maintain a clear surgical "bloodless" field, and to ensure proper bone-implant cementing. In 2007, over 600,000 TKAs were performed in the United States, and this number is projected to increase to 3.48 million procedures performed annually by 2030. The acute effects of tourniquet-induced ischemia-reperfusion (I/R) on human skeletal muscle cells are poorly understood and require critical investigation, as muscle atrophy following this surgery is rapid and represents the most significant clinical barrier to long-term normalization of physical function. To determine the acute effects of I/R on skeletal muscle cells, biopsies were obtained at baseline, maximal ischemia (prior to tourniquet release), and reperfusion (following tourniquet release). Quadriceps volume was determined before and 2 wk post-TKA by MRI. We measured a 36% decrease in phosphorylation of Akt Ser(473) during ischemia and 37% during reperfusion (P < 0.05). 4E-BP1 Thr(37/46) phosphorylation decreased 29% during ischemia and 22% during reperfusion (P < 0.05). eEF2 Thr(56) phosphorylation increased 25% during ischemia and 43% during reperfusion (P < 0.05). Quadriceps volume decreased 12% in the TKA leg (P < 0.05) and tended to decrease (6%) in the contralateral leg (P = 0.1). These data suggest cap-dependent translation initiation, and elongation may be inhibited during and after TKA surgery. We propose that cap-dependent translational events occurring during surgery may precipitate postoperative changes in muscle cells that contribute to the etiology of muscle atrophy following TKA.     

iGLASS: an improvement to the GLASS method for estimating species trees from gene trees

Several methods have been designed to infer species trees from gene trees while taking into account gene tree/species tree discordance. Although some of these methods provide consistent species tree topology estimates under a standard model, most either do not estimate branch lengths or are computationally slow. An exception, the GLASS method of Mossel and Roch, is consistent for the species tree topology, estimates branch lengths, and is computationally fast. However, GLASS systematically overestimates divergence times, leading to biased estimates of species tree branch lengths. By assuming a multispecies coalescent model in which multiple lineages are sampled from each of two taxa at L independent loci, we derive the distribution of the waiting time until the first interspecific coalescence occurs between the two taxa, considering all loci and measuring from the divergence time. We then use the mean of this distribution to derive a correction to the GLASS estimator of pairwise divergence times. We show that our improved estimator, which we call iGLASS, consistently estimates the divergence time between a pair of taxa as the number of loci approaches infinity, and that it is an unbiased estimator of divergence times when one lineage is sampled per taxon. We also show that many commonly used clustering methods can be combined with the iGLASS estimator of pairwise divergence times to produce a consistent estimator of the species tree topology. Through simulations, we show that iGLASS can greatly reduce the bias and mean squared error in obtaining estimates of divergence times in a species tree.