Discriminative stimulus effects of delta 9-tetrahydrocannabinol and delta 9-11-tetrahydrocannabinol in rats and rhesus monkeys

Previous reports have suggested that delta 9-11-tetrahydrocannabinol (delta 9-11-THC), an exocyclic analog of delta 9-tetrahydrocannabinol (delta 9-THC), may have weak agonist effects as well as antagonistic properties. The purpose of the present study was to examine the effects of delta 9-11-THC in substitution and antagonism tests in rats and in rhesus monkeys trained to discriminate delta 9-THC from vehicle in two-lever drug-discrimination procedures. The substitution studies showed that delta 9-11-THC generalizes from the training dose of delta 9-THC in rats and in monkeys, although it was less potent in both species. The magnitude of the potency difference was greater in monkeys than in rats. When administered immediately following injection with the training dose of delta 9-THC, delta 9-11-THC failed to block the delta 9-THC cue in rats and showed a lack of dose-responsive inhibition in monkeys. These results suggest that delta 9-11-THC is devoid of antagonistic properties in the drug discrimination paradigm.     

Identification of a poxvirus gene encoding a uracil DNA glycosylase

An open reading frame, BamHI D6R, from the central highly conserved region of the Shope fibroma virus (SFV) genome was sequenced and found to have significant homology to that of uracil DNA glycosylases from a number of organisms. Uracil DNA glycosylase catalyzes the initial step in the repair pathway that removes potentially mutagenic uracil from duplex DNA. The D6R polypeptide was expressed in reticulocyte lysates programmed with RNA transcribed from an expression vector containing the T7 RNA polymerase promoter. A highly specific ethidium bromide fluorescence assay of the in vitro translation product determined that the encoded protein does indeed possess uracil DNA glycosylase activity. Open reading frames from other poxviruses, including vaccinia virus (HindIII D4R) and fowlpox (D4), are highly homologous to D6R of SFV and are predicted to encode uracil DNA glycosylases. Identification of the SFV uracil DNA glycosylase provides evidence that this poxviral protein is involved in the repair of the viral DNA genome. Since this enzyme performs only the initial step required for the removal of uracil from DNA, creating an apyrimidinic site, we suggest that other, possibly virus-encoded, repair activities must be present in the cytoplasm of infected cells to complete the uracil excision repair pathway.     

CONVERGENCE AMONG REGIONS OF THE EUROPEAN UNION, 1950–1990

ABSTRACT The paper examines GDP per capita growth rated among subnational regions of the European Union between 1950 and 1990. Previous research has suggested that a slow process of convergence (or "catch-up") has occurred over the period since 1950. Estimation of a catch-up growth model using a modified and larger set of regions than previously the case suggests that existing measures of convergence rates need to be revised downwards and that convergence rates have been reduced in the 1970s and 1980s compared with the 1960s.     

Psychophysiological reactivity to mental arithmetic stress in Black and White normotensive men.

34 Black and 42 White male normotensives 34–55 yrs old performed a mental arithmetic task while blood pressure, heart rate, and skin conductance were recorded. Compared with Whites, Blacks had significantly higher baseline diastolic blood pressure and lower skin conductance levels. These effects persisted during performance of the mental arithmetic task. When baseline differences were covaried, there were no significant physiological effects associated with the task. There were no significant race or family history effects, and task performance did not influence the outcome. Failure to demonstrate greater cardiovascular reactivity in Blacks and all men with a positive family history of hypertension is discussed with regard to possible survivor effects and methodologic limitations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

KNOWLEDGE-BASED SYSTEMS FOR USERS

Although knowledge-based systems are already assisting help-desk staff in the IS department to solve systems development and similar problems, they have yet to become a fully functional part of user support help desks. The two adviser applications described in this article illustrate how easily these knowledge-based systems can be developed and, even more important, how more productive they can make the help-desk staff and the users themselves.     

Development of proton conductors using pyrochlore-perovskite phase boundaries

The pyrochlore-perovskite binary systems La₂Zr₂O₇-SrZrO₃ and La₂Zr₂O₇-LaYO₃ were studied as potential high-temperature proton conductors. X-ray diffraction and direct current conductivity measurements were used to develop empirical relationships between structure and conductivity. The solubilities of Sr in La₂Zr₂O₇ and La in SrZrO₃ were low, less than 0.1 mol fraction. The solubility of Zr in LaYO₃ was at least 0.125 mol fraction, and the solubility of Y in La₂Zr₂O₇ was at least 0.25 mol fraction. Y-doped La₂Zr₂O₇ had the highest electrical conductivity, though no composition exceeded σ=3×10⁻⁴ S/cm at the target temperature of 600 °C. The effectiveness of Y as a dopant in La₂Zr₂O₇ was limited because Y substituted for both La on the A-site and Zr on the B-site. This paper was presented at the Fuel Cells: Materials, Processing, and Manufacturing Technologies Symposium sponsored by the Energy/Utilities Industrial Sector & Ground Transportation Industrial Sector and the Specialty Materials Critical Technologies Sector at the ASM International Materials Solutions Conference, October 13–15, 2003, in Pittsburgh, PA. The symposium was organized by P. Singh, Pacific Northwest National Laboratory, S.C. Deevi, Philip Morris USA, T. Armstrong, Oak Ridge National Laboratory, and T. Dubois, U.S. Army CECOM.     

Neonatal 6-hydroxydopamine alters the behavior of enriched-impoverished rats in a novel test environment.

The hypothesis that neonatal norepinephrine (NE) depletion lessens the behavioral consequences of differential housing was tested. Male Wistar rats were injected with 6-hydroxydopamine (6-OHDA) or vehicle twice within 24 hr of birth, weaned at 25 days, and reared under either impoverished (IC) or enriched conditions (EC) for 30 days. In 3 experiments, rats were tested in the Morris water maze, the colony-intruder test, and 2 tests of dominance. 6-OHDA treatment reduced cortical and hypothalamic NE concentrations and increased brainstem NE concentrations. EC housing increased cortical dopamine (DA). Behavioral differences caused by postweaning enrichment–isolation were reduced by neonatal NE depletion, primarily in early test trials. The authors conclude that forebrain NE afferents from the locus coeruleus are important for housing-related behavioral changes and responsivity to novel testing environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)