Academic Librarians in Second Life

The multi-user virtual world Second Life is an online software platform that allows users to jointly explore realistic three-dimensional environments via avatar characters, communicate via voice and text chat, and collaborate using shared creation tools. Librarians and educators have been developing academic content and services in Second Life for use with students and other constituency groups since 2005. This study surveyed academic librarians working in Second Life to discover their perceptions of virtual world environments for teaching and learning and to gauge the impact of this technology on their work with faculty and students. Sixty-two librarians provided details on various aspects of their professional involvement in Second Life. Findings show that librarians from every type of academic institution, at all levels of advancement, and in every depart-ment participate in this virtual world. Results include details of roles and functions, as well as perceived benefits and challenges. Because many adolescents and teenagers worldwide are currently active virtual world participants, academic librarians in Second Life view virtual world technology as a significant near-future educational trend

Neuropsychological Characteristics of Preclinical Dementia in Parkinson's Disease

The goal of this study was to characterize the changes in cognition associated with the earliest, or preclinical, stages of dementia in Parkinson's disease (PD). We administered a comprehensive neuropsychological test battery to a group of initially nondemented PD patients participating in a longitudinal community-based epidemiologic study. We used Cox proportional hazards models to assess the relative risk of incident dementia associated with baseline scores on the neuropsychological tests. Baseline performance on two verbal fluency tasks (letter fluency and category fluency) was significantly and independently associated with incident dementia. Tests of memory, orientation, abstract reasoning, naming, and constructional skill were less sensitive predictors of subsequent dementia. The neuropsychological pattern characterizing the preclinical stages of dementia in PD differed from that described previously in preclinical Alzheimer's disease. Results suggest that poor performance on tests of verbal fluency may represent a distinct characteristic of the preclinical phase of dementia in PD

Memory and Executive Function Impairment Predict Dementia in Parkinson's Disease

We analyzed the association of neuropsychological test impairment at baseline with the development of dementia in idiopathic Parkinson's disease (PD) patients. A cohort of nondemented PD patients from northern Manhattan, NY was followed annually with neurological and neuropsychological evaluations. The neuropsychological battery included tests of verbal and nonverbal memory, orientation, visuospatial ability, language, and abstract reasoning. The association of baseline neuropsychological tests scores with incident dementia was analyzed using Cox proportional hazards models. The analysis controlled for age, gender, education, duration of PD, and the total Unified Parkinson's Disease Rating Scale motor score at baseline. Forty-five out of 164 patients (27%) became demented during a mean follow-up of 3.7 ± 2.3 years. Four neuropsychological test scores were significantly associated with incident dementia in the Cox model: total immediate recall (RR: 0.92, 95% CI: 0.87–0.97, P = 0.001) and delayed recall (RR: 0.73, 95% CI: 0.59–0.91, P = 0.005) of the Selective Reminding Test (SRT), letter fluency (RR: 0.87, 95% CI: 0.77–0.99, P = 0.03), and Identities and Oddities of the Mattis Dementia Rating Scale (RR: 0.85, 95% CI: 0.73–0.98, P = 0.03). When the analysis was performed excluding patients with a clinical dementia rating of 0.5 (questionable dementia) at baseline evaluation, total immediate recall and delayed recall were still predictive of dementia in PD. Our results indicate that impairment in verbal memory and executive function are associated with the development of dementia in patients with PD

Postmenopausal Estrogen Use and Parkinson's Disease with and without Dementia

We investigated the effects of estrogen replacement therapy (ERT) on the risk of development of dementia in 87 women with Parkinson's disease without dementia (PDND), 80 women with Parkinson's disease with dementia (PDD), and 989 nondemented healthy women from the same community. ERT was protective for the development of dementia within the setting of PD (OR 0.22, 95% CI 0.05-1.0) and when PDD patients were compared with controls (OR 0.24, 95% CI 0.07-0.78), but did not affect the risk of PD. The results of the study suggest that a randomized clinical trial of ERT may be warranted. Risk factors for Parkinson's disease with dementia (PDD) include age at onset of the motor signs of PD, the presence of severe extrapyramidal signs, and depression.1 It is unknown to what extent PDD overlaps with Alzheimer's disease (AD) or whether the risk factors for AD are also risk factors for PDD. ApoE4 has not been associated with PDD, and no other genetic susceptibility loci for PDD have been identified. Three prospective, observational studies demonstrated reduced risk and delayed age at onset of AD in postmenopausal women who used estrogen,2-4 whereas one did not.5 To determine whether estrogen replacement therapy(ERT) reduced the risk of dementia in women with PD, estrogen usage was ascertained in 167 women with PD, 80 of whom were demented, as well as in 989 nondemented women from the same community

Prospective Comparative Study of the Evolution of Probable Alzheimer's Disease and Parkinsons's Disease Dementia

No previous comparison of test performance in probable Alzheimer's disease (pAD) and Parkinson's disease (PD) dementia has provided information about potential differences in the dementing process. This study compared the evolution of cognitive changes associated with these dementias. Generalized estimating equations (GEE) applied to regression analyses with repeated measures were used to evaluate cognitive changes over 1 to 3 years prior to the point when dementia was diagnosed in 40 matched pairs of patients with incident pAD and PD dementia. Both groups' performance declined on the Short Blessed, Selective Reminding Test (SRT; total recall, long-term retrieval, and delayed recall), Boston Naming Test, Category Fluency, and Similarities. The decline on naming and SRT delayed recall was more rapid in the PD dementia group, suggesting that these performance deficits emerge earlier in the development of pAD. The PD dementia group performed worse on Category Fluency throughout the follow-up period, suggesting either that dementia is overlaid on this preexisting performance deficit or that this type of executive deficit is an early manifestation of dementia in PD. The pAD group performed more poorly throughout the follow-up period on SRT delayed recognition, consistent with a pAD-specific encoding deficit. We conclude that while pAD and PD dementia are similar in many respects, differences in their evolution support previous observation of unique features in the 2 dementias and suggest different underlying pathologies

Delayed Toxicity Associated with Soluble Anthrax Toxin Receptor Decoy-Ig Fusion Protein Treatment

Soluble receptor decoy inhibitors, including receptor-immunogloubulin (Ig) fusion proteins, have shown promise as candidate anthrax toxin therapeutics. These agents act by binding to the receptor-interaction site on the protective antigen (PA) toxin subunit, thereby blocking toxin binding to cell surface receptors. Here we have made the surprising observation that co-administration of receptor decoy-Ig fusion proteins significantly delayed, but did not protect, rats challenged with anthrax lethal toxin. The delayed toxicity was associated with the in vivo assembly of a long-lived complex comprised of anthrax lethal toxin and the receptor decoy-Ig inhibitor. Intoxication in this system presumably results from the slow dissociation of the toxin complex from the inhibitor following their prolonged circulation. We conclude that while receptor decoy-Ig proteins represent promising candidates for the early treatment of B. anthracis infection, they may not be suitable for therapeutic use at later stages when fatal levels of toxin have already accumulated in the bloodstream

Gag Mutations Strongly Contribute to HIV-1 Resistance to Protease Inhibitors in Highly Drug-Experienced Patients besides Compensating for Fitness Loss

Human immunodeficiency virus type 1 (HIV-1) resistance to protease inhibitors (PI) results from mutations in the viral protease (PR) that reduce PI binding but also decrease viral replicative capacity (RC). Additional mutations compensating for the RC loss subsequently accumulate within PR and in Gag substrate cleavage sites. We examined the respective contribution of mutations in PR and Gag to PI resistance and RC and their interdependence using a panel of HIV-1 molecular clones carrying different sequences from six patients who had failed multiple lines of treatment. Mutations in Gag strongly and directly contributed to PI resistance besides compensating for fitness loss. This effect was essentially carried by the C-terminal region of Gag (containing NC-SP2-p6) with little or no contribution from MA, CA, and SP1. The effect of Gag on resistance depended on the presence of cleavage site mutations A431V or I437V in NC-SP2-p6 and correlated with processing of the NC/SP2 cleavage site. By contrast, reverting the A431V or I437V mutation in these highly evolved sequences had little effect on RC. Mutations in the NC-SP2-p6 region of Gag can be dually selected as compensatory and as direct PI resistance mutations, with cleavage at the NC-SP2 site behaving as a rate-limiting step in PI resistance. Further compensatory mutations render viral RC independent of the A431V or I437V mutations while their effect on resistance persists