50 research outputs found

    Mecamylamine, dihydro-β-erythroidine, and dextromethorphan block conditioned responding evoked by the conditional stimulus effects of nicotine

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    Current smokers express the desire to quit. However, the majority find it difficult to remain abstinent. As such, research efforts continually seek to develop more effective treatment. One such area of research involves the interoceptive stimulus effects of nicotine as either a discriminative stimulus in an operant drug discrimination task, or more recently as a conditional stimulus (CS) in a discriminated goal-tracking task. The present work investigated the potential role nicotinic acetylcholine receptors in the CS effects of nicotine (0.4 mg/kg) using antagonists with differential selectivity for β2*, α7*, α6β2*, and α3β4* receptors. Methyllycaconitine (MLA) had no effect on nicotine-evoked conditioned responding. Mecamylamine and dihydro-β-erythroidine (DHβE) dose dependently blocked responding evoked by the nicotine CS. In a time-course assessment of mecamylamine and DHβE, each blocked conditioned responding when given 5 min before testing and still blocked conditioned responding when administered 200 min before testing. Two novel bis-picolinium analogs (N, N’-(3, 3′-(dodecan-1,12-diyl)-bis-picolinium dibromide [bPiDDB], and N, N’- (decan-1,10-diyl)-bis-picolinium diiodide [bPiDI]) did not block nicotine-evoked conditioned responding. Finally, pretreatment with low dose combinations of mecamylamine, dextromethorphan, and/or bupropion were used to target α3β4* receptors. No combination blocked conditioned responding evoked by the training dose of nicotine. However, a combination of mecamylamine and dextromethorphan partially blocked nicotine-evoked conditioned responding to a lower dose of nicotine (0.1 mg/kg). These results indicate that β2* and potentially α3β4* nicotinic acetylcholine receptors play a role in the CS effects of nicotine and are potential targets for the development of nicotine cessation aids

    Mecamylamine, dihydro-β-erythroidine, and dextromethorphan block conditioned responding evoked by the conditional stimulus effects of nicotine

    Get PDF
    Current smokers express the desire to quit. However, the majority find it difficult to remain abstinent. As such, research efforts continually seek to develop more effective treatment. One such area of research involves the interoceptive stimulus effects of nicotine as either a discriminative stimulus in an operant drug discrimination task, or more recently as a conditional stimulus (CS) in a discriminated goal-tracking task. The present work investigated the potential role nicotinic acetylcholine receptors in the CS effects of nicotine (0.4 mg/kg) using antagonists with differential selectivity for β2*, α7*, α6β2*, and α3β4* receptors. Methyllycaconitine (MLA) had no effect on nicotine-evoked conditioned responding. Mecamylamine and dihydro-β-erythroidine (DHβE) dose dependently blocked responding evoked by the nicotine CS. In a time-course assessment of mecamylamine and DHβE, each blocked conditioned responding when given 5 min before testing and still blocked conditioned responding when administered 200 min before testing. Two novel bis-picolinium analogs (N, N’-(3, 3′-(dodecan-1,12-diyl)-bis-picolinium dibromide [bPiDDB], and N, N’- (decan-1,10-diyl)-bis-picolinium diiodide [bPiDI]) did not block nicotine-evoked conditioned responding. Finally, pretreatment with low dose combinations of mecamylamine, dextromethorphan, and/or bupropion were used to target α3β4* receptors. No combination blocked conditioned responding evoked by the training dose of nicotine. However, a combination of mecamylamine and dextromethorphan partially blocked nicotine-evoked conditioned responding to a lower dose of nicotine (0.1 mg/kg). These results indicate that β2* and potentially α3β4* nicotinic acetylcholine receptors play a role in the CS effects of nicotine and are potential targets for the development of nicotine cessation aids

    Precise Quantitation of the Latent HIV-1 Reservoir: Implications for Eradication Strategies

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    The quantitative viral outgrowth assay (QVOA) provides a precise minimal estimate of the reservoir of resting CD4+ T-cell infection (resting cell infection [RCI]). However, the variability of RCI over time during antiretroviral therapy (ART), relevant to assess potential effects of latency-reversing agents or other interventions, has not been fully described. We performed QVOA on resting CD4+ T cells obtained via leukapheresis from 37 human immunodeficiency virus (HIV)–infected patients receiving stable suppressive ART for a period of 6 years. Patients who started ART during acute (n = 17) or chronic (n = 20) HIV infection were studied once HIV RNA levels were 6-fold were rare. We suggest that a 6-fold decline is a relevant threshold to reliably identify effects of antilatency interventions on RCI

    Incident Sexually Transmitted Infection as a Biomarker for High-Risk Sexual Behavior After Diagnosis of Acute HIV

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    Sexually transmitted infection (STI) diagnosis following diagnosis of acute HIV infection (AHI) indicates ongoing high-risk sexual behavior and possible risk of HIV transmission. We assessed predictors of STI acquisition and the effect of time since care entry on STI incidence in AHI patients in care and receiving consistent risk-reduction messaging

    Removing the invisibility cloak: Using space design to influence patron behavior and increase service desk usage

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    In small branch libraries, patrons seeking assistance from library staff outside of the dedicated single-service desk often results in large staffing inefficiencies. This paper presents a case study in which the authors applied behavioral psychology models to a branch library’s space arrangement to identify possible factors influencing patron service point choices. A subsequent full space rearrangement was instituted which utilized human behavior research, service desk design principles, and low-cost methods to create a space that reduced barriers and influenced patrons back to the main service desk. The paper reports on the 11-month study that followed and the impact the rearrangement had on patron behavior. Results indicate that simple rearrangement of existing furniture and equipment into new configurations have direct influence on service desk usage and can encourage new patron behaviors. Space and human behavior are inherently connected and library managers should establish goals for how they envision their spaces to be used and arrange them in ways that encourage wanted behaviors.Ye

    Relic neutrino masses and the highest energy cosmic rays

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    We consider the possibility that a large fraction of the ultrahigh energy cosmic rays are decay products of Z bosons which were produced in the scattering of ultrahigh energy cosmic neutrinos on cosmological relic neutrinos. We compare the observed ultrahigh energy cosmic ray spectrum with the one predicted in the above Z-burst scenario and determine the required mass of the heaviest relic neutrino as well as the necessary ultrahigh energy cosmic neutrino flux via a maximum likelihood analysis. We show that the value of the neutrino mass obtained in this way is fairly robust against variations in presently unknown quantities, like the amount of neutrino clustering, the universal radio background, and the extragalactic magnetic field, within their anticipated uncertainties. Much stronger systematics arises from different possible assumptions about the diffuse background of ordinary cosmic rays from unresolved astrophysical sources. In the most plausible case that these ordinary cosmic rays are protons of extragalactic origin, one is lead to a required neutrino mass in the range 0.08 eV - 1.3 eV at the 68 % confidence level. This range narrows down considerably if a particular universal radio background is assumed, e.g. to 0.08 eV - 0.40 eV for a large one. The required flux of ultrahigh energy cosmic neutrinos near the resonant energy should be detected in the near future by AMANDA, RICE, and the Pierre Auger Observatory, otherwise the Z-burst scenario will be ruled out.Comment: 19 pages, 22 figures, REVTeX

    Integrating social science into conservation planning

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    A growing body of literature has highlighted the value of social science for conservation, yet the diverse approaches of the social sciences are still inconsistently incorporated in conservation initiatives. Building greater capacity for social science integration in conservation requires frameworks and case studies that provide concrete guidance and specific examples. To address this need, we have developed a framework aimed at expanding the role for social science in formal conservation planning processes. Our framework illustrates multiple ways in which social science research can contribute to four stages of such processes: 1) defining the problem and project team; 2) defining goals; 3) identifying impact pathways and designing interventions; and 4) developing and evaluating indicators of success (or failure). We then present a timely case study of wolf reintroduction in Colorado, U.S.A., to demonstrate the opportunities, challenges, and complexities of applying our framework in practice

    Genomic Targets of Brachyury (T) in Differentiating Mouse Embryonic Stem Cells

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    The T-box transcription factor Brachyury (T) is essential for formation of the posterior mesoderm and the notochord in vertebrate embryos. Work in the frog and the zebrafish has identified some direct genomic targets of Brachyury, but little is known about Brachyury targets in the mouse.Here we use chromatin immunoprecipitation and mouse promoter microarrays to identify targets of Brachyury in embryoid bodies formed from differentiating mouse ES cells. The targets we identify are enriched for sequence-specific DNA binding proteins and include components of signal transduction pathways that direct cell fate in the primitive streak and tailbud of the early embryo. Expression of some of these targets, such as Axin2, Fgf8 and Wnt3a, is down regulated in Brachyury mutant embryos and we demonstrate that they are also Brachyury targets in the human. Surprisingly, we do not observe enrichment of the canonical T-domain DNA binding sequence 5'-TCACACCT-3' in the vicinity of most Brachyury target genes. Rather, we have identified an (AC)(n) repeat sequence, which is conserved in the rat but not in human, zebrafish or Xenopus. We do not understand the significance of this sequence, but speculate that it enhances transcription factor binding in the regulatory regions of Brachyury target genes in rodents.Our work identifies the genomic targets of a key regulator of mesoderm formation in the early mouse embryo, thereby providing insights into the Brachyury-driven genetic regulatory network and allowing us to compare the function of Brachyury in different species
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