Further evidence that naloxone acts as an inverse opiate agonist: implications for drug dependence and withdrawal

To test if naloxone behaved as an inverse agonist rather than as an antagonist we evaluated its responses in guinea-pig ilea with and without morphine (480 nM, 24 h). In control ilea, naloxone (100 nM) had no effect. In morphine-treated ilea, naloxone as a bolus, but not as an infusion, elicited an abstinence response. Preadministration of naloxone blocked the response to subsequent administrations. Similarly, naloxone failed to produce an abstinence response in ilea pretreated with kappa compounds (bremazocine, U50488 or xorphanol 100 nM) or with kinase inhibitors (H7 or H8 30 microM). These findings can be interpreted in the light of the two-state receptor model if naloxone behaves as an inverse agonist: Incubation with morphine increased the active state of receptors making them susceptible to the inverse agonist (naloxone); exposure to naloxone favored the inactive conformation making them insensitive to further administration of naloxone; kappa compounds behaved as antagonists preventing the response to naloxone; and kinase inhibitors interfered with the active conformation making the system insensitive to naloxone. According to this model, dependence can be viewed as an overexpression of the active receptors and withdrawal as an abrupt change from the active to the inactive state.     

Poly(lactic acid)/low‐density polyethylene blends and its nanocomposites based on sepiolite

Poly(lactic acid) (PLA) nanocomposite ternary blends based on unmodified sepiolite were prepared by melt blending using a corotating twin‐screw extruder. Two grafted polymers were used as compatibilizer agents, in an effort to increase the PLA tensile toughness. The influence of incorporating a low‐cost commodity low‐density polyethylene, as dispersed phase to the composites on thermal degradation, and rheological and tensile properties was studied. The morphology of the blends and composites was determined through transmission and scanning electron microscopy techniques. Results showed that the compatibilized blends prepared without clay have higher thermal degradation susceptibility and tensile toughness than those prepared with sepiolite and significant changes in complex viscosity and melt elasticity values were observed between them. The nanocomposite blends exhibited similar thermal degradation, lower tensile strength, and Young's modulus values and increased elongation at break and tensile toughness, complex viscosity, and storage modulus compared with those of the nanocomposite of PLA. These results are related to the clay dispersion, to the type of morphology of the different blends, to the localization of the sepiolite in the different phases, the thermomechanical degradation of the PLA matrix phase during melt blending and the grafting degree of the compatibilizers used. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Metropolitan Latino Political Behavior: Voter Turnout and Candidate Preference in Los Angeles

Abstract: Most research on Latino voting behavior conclusively finds that as a group, Latinos vote at lower rates than other racial and ethnic groups in the United States. In this article, we argue that given the appropriate circumstances, Latinos should be expected to vote at higher rates than other racial and ethnic groups. In particular, we think the presence of a viable Latino candidate will spur increased Latino turnout and that when Latinos candidates run for office, Latino voters will prefer the co‐ethnic candidate. Analyzing precinct level returns from the Los Angeles 2001 mayoral and the 2000 presidential elections we show this may be the case. High‐density Latino precincts show higher rates of turnout when Latino candidates are on the ballot, and these same precincts show heightened support for the co‐ethnic candidate. In fact, for the first time ever in Los Angeles, the 2001 mayoral election witnessed Latinos voting at the highest rates of any racial or ethnic group in the city.     

Adenovirus-mediated overexpression of human transforming growth factor-beta 1 in rat cardiac fibroblasts, myocytes and smooth muscle cells

Transforming growth factor-beta 1 (TGF-beta 1) is known to regulate cardiac cell function and its overexpression in the heart is thought to contribute to the development of cardiac hypertrophy and fibrosis. We wished to develop a high efficiency gene transfer method that could be used both in vitro and in vivo and result in the overexpression of TGF-beta 1. For this purpose, we constructed a replication-deficient human adenovirus 5 vector encoding for human TGF-beta 1 and used for control purposes an adenovirus lacZ vector. The adenovirus 5 construct was capable of infecting neonatal rat cardiac myocytes, fibroblasts and VSMCs. Of the three cell types, cardiac myocytes appear more susceptible to infection by the adenovirus 5 construct as assessed through beta-galactosidase staining. Infection of cardiac fibroblasts, myocytes and VSMCs with the hTGF-beta 1 adenovirus leads to the expression of hTGF-beta 1 mRNA and enhanced levels of bioactive and total TGF-beta 1 protein. Infection with hTGF-beta 1 adenovirus also results in enhanced levels of collagen type III gene expression in VSMCs and fibroblasts whereas in cardiac myocytes it leads to increased levels for sarcomeric and beta-actin. Thus, this adenoviral vector might be used for the exploration of in vivo effects of altered levels of cardiac TGF-beta 1.     

Low complexity M‐PPM impulse‐radio ultra wideband over fiber system for wireless sensor networks applications

Ultra wideband over fiber (UWBoF) systems have been proposed to extend wireless range and to interconnect stand‐alone UWB networks. These systems have focused on high‐data‐rate applications. However, UWB will be a key enabler for low‐data‐rate wireless sensor network (WSN) deployments. In this letter, a low‐cost and low‐complexity M‐ary pulse position modulation (PPM) impulse radio (IR)‐UWBoF system designed for WSNs applications is proposed. A spectral line‐suppressive convolutional code is used to achieve spectral line suppression in the power spectral density (PSD). Experimental results show that the system does not distort or add spectral lines to the IR‐UWB signal PSD transmitted over 30 km of a single‐mode fiber, thus demonstrating its feasibility to interconnect WSN deployments. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Effect of ageing and μ-calpain markers on meat quality from Brangus steers finished on pasture

Brangus steers (n = 247) finished on pasture were used to evaluate the effects of post-mortem ageing and polymorphism CAPN1 316 and CAPN1 4751 markers on meat tenderness and objective colour measurements (CIEL*a*b*) of m. Longissimus dorsi. Ageing meat for 7 days decreased shear force (SF) by 13.7% and improved a* (8.4%) and b* (10%) compared to ageing for 1 day. No difference between 7 and 14 days of ageing was found for SF, a* and b*. However, L* increased markedly with ageing. Fitting both markers simultaneously, CAPN1 316 showed association with SF and L* and CAPN1 4751 with a* and b*. Fitting the markers individually, CAPN1 4751 affected all traits and CAPN1 316 showed association with SF and L*. Post-mortem ageing and the use of markers represent two independent and alternative tools that could be used for improving quality of meat from Brangus cattle.     

Minimum “safe cycle time”: Selecting the frozen layer thickness

Predicting the minimum safe cycle time in injection molding is complicated by the cyclic nature of the process. The mold thermal state changes with continuous molding until a quasi steady state is achieved. In the first part of these series, we presented and experimentally tested a simple approach to predict part and mold surface temperature during continuous molding. In this work, we evaluate the minimum frozen layer thickness required before the part can be demolded and how the growth of this frozen layer is affected as the mold thermal state changes with continuous molding cycles. Experiments are used to relate the minimum frozen layer thickness to dimensional stability. Based on these experiments, statistical tools are used to select an ejection criterion to obtain a minimum safe cooling time. We show that the ejection criteria should be adjusted depending on the precision required from the molded parts. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers