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.     

Novelty-seeking temperament in captive stumptail macaques (macaca arctoides) and spider monkeys (ateles geoffroyi).

Novelty-seeking temperament is defined as the reaction to novel or risk situations and objects, and by the global disposition to explore such stimuli. Our purpose was to describe and compare this trait in primates. For this purpose, a risk-taking Index, a curiosity index, and a novelty-seeking index were correlated to several biosocial variables using 22 captive stumptail macaques (Macaca arctoides) and 7 captive spider monkeys (Ateles geoffroyi). Spider monkeys scored higher than macaques, males of both species scored higher than females, and dominant macaques were evaluated as more novelty seekers. We suggest that these differences may be because of, among other reasons, the particular social system of each species. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Formation of tetramethylethylene radical cations after pentane adsorption on sulfated zirconia

Tetramethylethylene radical cations have been registered by ESR after pentane adsorption on sulfated zirconia. The radical cations proved to be not stable in the presence of oxygen, only molecular oxygen radical anions being registered. Tetramethylethylene formation and pentane disproportionation are shown to occur under illumination within the same spectral region proving that the former is formed as a by-product of pentane transformations.     

Preparation of MoS2 and WS2 catalysts by in situ decomposition of ammonium thiosalts

The in situ decomposition of ammonium thiometallates during the hydrodesulfurization (HDS) of dibenzothiophene (DBT), to obtain molybdenum disulfide and tungsten disulfide catalysts, was investigated. It was found that very efficient catalysts for the HDS of DBT were obtained by in situ decomposition. Mechanical uniaxial pressing of the precursors (ammonium thiometallates) affected both textural and catalytic properties of the catalysts. Surface areas of molybdenum and tungsten disulfides increased as a function of uniaxial pressing, while catalytic activities went through a maximum. For MoS₂, the hydrogenation selectivity was much higher for in situ catalysts than for ex situ ones. For WS₂ catalysts, the hydrogenation selectivity was less sensitive to the condition of decomposition (ex situ/in situ). The surface S/M (M = Mo, W) atomic ratio from the Auger signal decreased as a function of uniaxial pressing, while the C/M ratio remained almost constant at 1.6. The best catalyst showed an experimental S/Mo ratio that is slightly higher than the stoichiometric value. The effect of in situ decomposition and mechanical deformation of thiometallate precursors is discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Evaluation of early manifestations of chronic no transmitted diseases risk in school population in Cali - Colombia

Similar to other countries in America, Colombia and the Department of Valle present changes in their population structure and mortality suggesting an advanced epidemiological transition status. Grouped, chronic diseases represent the principal cause of death in municipalities with high urban concentration. To identify associated factors of chronic conditions later in life, school children stratified by age, socio-economic level and gender were studied. By random sampling of 14 schools 2.807 children were examined to measure: anthropometry, work capacity, food intake, sexual maturation, blood pressure, and blood levels of glucose and lipids. Weight and height for all ages and gender were lower than international reference but higher than in previous studies. On the contrary body mass indicators were higher. Work capacity adjusted for body weight was higher in low income children. Mean age of menarche was 11,9 years. The relative peak of growth was 11 years for girls and 14 for boys. Maturity was reached at 12 years in women and 17 in men. Blood lipids were considered high and borderline high in a large proportion of the students, while 19.5% had systolic blood pressure > or = 120 mm. and 24% diastolic > or = 70. Intake of protein and energy was adequate, but diet was high in fat and sugar. There was not deficiency in macro nutrients but dietary intake of some minerals was low, specially iron and calcium. The findings indicate a population with unbalanced diet and disturbing high body mass and lipid concentration that could represent in the future an increase in the already high prevalence of chronic diseases.     

Effect of pyruvate on lens myo-inositol transport and polyol formation in diabetic cataract

Attitudes toward deviant behavior that might indicate psychiatric disorder were investigated among the Inuit of Northern Québec (Nunavik). In a convenience sample of 137 Inuit adults, respondents were randomly presented with one of six different vignettes that described a man with "strange" behavior who was either threatening or withdrawn and whose problem was labeled either "isumaluttuq" ("burdened or weighed down by thoughts"), "demon possession," or "mental illness." Respondents rated their willingness to live, work, or hunt with this person and allow him into their family on a social distance scale. Significant predictors of greater social distance were female gender, more education, less familiarity with the behavior, and perception of the person as less likely to recover. There were no significant effects of vignette behavior or label on social distance ratings. Rating of likelihood of recovery was influenced by the vignette label, with isumaluttuq associated with less chance of recovery. Ascribing strange behavior to morally wrong action and to spirits or demons were highly inter-correlated and each was associated with perception of greater likelihood of recovery. Results suggest that Inuit attitudes toward deviant behavior are influenced more by perceived familiarity and likelihood of recovery than by labels, causal attributions, or explanations. The indigenous psychological concept of isumaluttuq does not serve to reduce social stigma. Efforts to promote the community integration of psychiatric patients through education should aim to increase familiarity with the problematic behavior and emphasize potential for recovery.     

Microwave Spectroscopy in YBCO Superconductors: Influence of Neutron Irradiation on the 123 Phase

The high-T _c superconducting system YBa₂Cu₃O:Li (123) was investigated by microwave absorption. The effect of neutron irradiation on the 123 phase as well as the dependence of the resulting modification both on the neutron fluence and on the doping behavior with Li are discussed. The results show a significant improvement of the superconducting characteristics: critical temperature, phase homogeneity, and critical current densities for a certain neutron fluence. We have found that the optinum neutron fluence for irradiation is 4.98×10²¹ m^–2.     

Diode-Pumped Nd:FAP Laser at 1.126 microm: A Possible Local Oscillator for a Hg+ Optical Frequency Standard

We report the efficient operation of a continuous-wave, single-frequency, diode-pumped Nd:FAP laser at 1.126 mum. When frequency quadrupled, such a laser might be used as a local oscillator for an optical frequency standard based on the single-photon (2)S(1/2)-(2)D(5/2) electric quadrupole transition of a trapped and laser-cooled (199)Hg(+) ion. Since the frequencies of the atomic transition and the laser are harmonically related, this scheme helps to simplify the measurement of the S-D clock transition frequency by a phase-coherent chain to the cesium primary frequency standard.