Cognitive decline and human (Homo sapiens) aging: An investigation using a comparative neuropsychological approach.

Using a comparative neuropsychological approach, the authors compared performance of younger and healthy older adults ages 65 and over on tasks originally developed to measure cognition in animals. A battery of 6 tasks was used to evaluate object discrimination, egocentric spatial abilities, visual and spatial working memory, and response shifting. Older adults performed more poorly than younger adults on tasks that evaluate egocentric spatial abilities, response shifting, and to a lesser extent object recognition. The two groups did not differ for tasks that evaluate spatial working memory and object discrimination. The impairments the authors observed in tasks that evaluate response shifting and object recognition are consistent with those found in canines and primates as well as those found in Alzheimer's disease. The results are consistent with the notion that cognitive processes supported by the amygdala and the orbitofrontal cortex are among the first to decline with increasing age in both humans and animals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bilateral frontal lobe disease and selective delayed response deficits in humans.

Compared the performance of 6 male patients (aged 24–65 yrs) with frontal lobe disease; 17 amnesic male patients (12 with etiology of alcoholic Korsakoff's disease [mean age 53.6 yrs] and 5 with surgically treated ruptured anterior communicating artery aneurysm [mean age 45.6 yrs]), and 12 male alcoholic controls (mean age 39.7 yrs) with no memory impairment on delayed alternation (DA) and delayed response (DR) tasks, known to be sensitive to frontal lobe damage in nonhuman primates. Ss (except the Korsakoff and alcoholic Ss) completed the Wechsler Memory Scale, and all Ss completed the Wechsler Adult Intelligence Scale (WAIS) and the Wisconsin Card Sorting Test. Results show that bilateral frontal lobe damage was associated with impairment on both tasks. There was no relation between performances on DA and DR and performance on the Wechsler Memory Scale, strengthening the suggestion that the former tasks are not sensitive to anterograde amnesia in humans. (41 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contingent pay and intrinsic task interest: Moderating effects of work values.

Examined the hypothesis that Ss' work value orientations would moderate the effect that contingent extrinsic incentives may have in reducing intrinsic task interest. 74 business undergraduates were administered demographic and work value questionnaires and the Clerical Abilities subtest of the Short Employment Tests. Ss were asked to proofread 2 short stories (high interest) or 2 law review article sections (low interest) under noncontingent, contingent, or no-pay conditions. Analyses showed that under contingent pay conditions, Ss with relatively higher extrinsic than intrinsic work values reported lower task satisfaction than Ss with relatively higher intrinsic work values. In contrast, under no-pay conditions, Ss with relatively higher extrinsic than intrinsic work values were actually more satisfied than their intrinsic counterparts. Results, therefore, support the existence of both an overjustification and an insufficient justification effect for financial incentives. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

ML iterative soft-decision-directed (ML-ISDD): a carrier synchronization system for short packet turbo coded communication

Modern communication systems are required to provide services based on high data rates burst-mode packet-data transmission, capable of operating at very low SNR conditions. Turbo codes enable the operation at low SNR, close to the Shannon limit. However, carrier frequency and phase synchronization, needed for optimal coherent performance of the receiver, still remains a problem in low SNR and short bursts conditions. This paper proposes a new carrier synchronization method, the Maximum-Likelihood Iterative-Soft-Decision-Directed (ML-ISDD), which uses the turbo-decoder soft decisions to improve the carrier synchronization performance at low SNR values. The ML-ISDD method operates iteratively and jointly with the turbo decoder, enhancing both the turbo-decoder and the synchronization performance. The ML-ISDD method has been shown by simulation to significantly increase the allowed initial frequency and phase uncertainty region, thus allowing the use of very short training sequences for initial carrier synchronization.     

Biased TCR repertoire in infiltrating lesional T cells in human Bancroftian filariasis

To investigate the hypothesis that T cells recognizing specific Ags localize to the site of disease activity in human bancroftian filariasis, we have compared the repertoire of TCR Vbeta gene segments in lesions vs blood in individual patients by RT-PCR ELISA. Vbeta14 and Vbeta24 were overrepresented (5% greater in tissue compared with PBMCs and/or tissue/PBMC ratios in the highest 5% of all tissue/PBMC ratios for all Vbetas for all subjects) in 50% and 40% of study subjects, respectively. Overrepresentation of these two Vbetas did not occur in any control subject. In comparing three patient groups, the proportion of individuals meeting at least one criterion for Vbeta14 overrepresentation was shown to increase in tandem with our current concepts of disease progression (asymptomatic filariasis = 25%; clinical filariasis with active infection = 60%; clinical filariasis without active infection = 71%). In 6 of the 10 individuals with Vbeta14 overrepresentation, Vbeta14 represented >20% of the entire lesional Vbeta repertoire. All but one of the 20 study subjects had at least one Vbeta gene segment that was overrepresented in tissue compared with PBMCs. Only a small number of Vbetas, usually three or less, were overrepresented in any single filariasis patient. However, in the same tissue, no differences between patient groups were found when IFN-gamma, TNF-alpha, IL-4, IL-5, and IL-12 mRNA expression were examined. Taken together, these findings suggest that, in principle, in essentially all patients, whether with subclinical or with clinical filariasis, distinct and limited T cell populations are concentrated in affected tissue.     

Extreme leukoreduction of major histocompatibility complex class II positive B cells enhances allogeneic platelet immunity

In a murine model of platelet alloimmunization, we examined the definitive role that mononuclear cells (MC) have in modulating platelet immunity by using platelets from severe combined immunodeficient (SCID) mice. CB.17 (H-2(d)) SCID or BALB/c (H-2(d)) mouse platelets were transfused weekly into fully allogeneic CBA (H-2(k)) mice and antidonor antibodies measured by flow cytometry. MC levels in BALB/c platelets were 1.1 +/- 0.6/microL and SCID mouse platelets could be prepared to have significantly lower (<0. 05/microL) MC numbers. Transfusions with 10(8) BALB/c platelets (containing approximately 100 MC/transfusion) stimulated IgG antidonor antibodies in 100% of the recipients by the fifth transfusion, whereas 10(8) SCID mouse platelets (containing approximately 5 MC/transfusion) stimulated higher-titered IgG alloantibodies by the second transfusion. When titrations of BALB/c peripheral blood MC were added to the SCID mouse platelets, levels approaching 1 MC/microL reduced SCID platelet immunity to levels similar to BALB/c platelets. Characterization of the alloantibodies showed that the low levels of MC significantly influenced the isotype of the antidonor IgG; the presence of 1 MC/microL was associated with induction of noncomplement fixing IgG1 antidonor antibodies, whereas platelet transfusions, devoid of MC (<0. 05/microL), were responsible for complement-fixing IgG2a production. When magnetically sorted defined subpopulations of MC were added to the SCID platelets, major histocompatability complex (MHC) class II positive populations, particularly B cells, were found to be primarily responsible for the reduced SCID mouse platelet immunity. The presence of low numbers of MC within the platelets was also associated with an age-dependent reduction in platelet immunogenicity; this relationship however, was not observed with SCID mouse platelets devoid of MC. The results suggest that a residual number of MHC class II positive B cells within allogeneic platelets are required for maximally reducing alloimmunization.     

Long-term intravesical oxybutynin chloride therapy in children with myelodysplasia

PURPOSE: We evaluated the clinical use of long-term intravesical oxybutynin chloride in the treatment of neurogenic bladder dysfunction in children with myelodysplasia who could not tolerate oral anticholinergics. MATERIALS AND METHODS: We retrospectively reviewed the records of all patients recommended for intravesical oxybutynin chloride therapy. A total of 12 girls and 18 boys 1 to 17 years old was recruited for study. Oxybutynin chloride (5 mg.) was instilled 2 times daily and pretreatment cystograms were compared to followup urodynamic studies. Duration of therapy was 2 to 26 months (mean 13, median 12). RESULTS: Mean total capacity plus or minus standard deviation increased from 209 +/- 103 to 282 +/- 148 ml. (p < 0.01), mean safe capacity increased from 157 +/- 105 to 234 +/- 147 ml. (p < 0.01) and mean age adjusted safe capacity increased from 76 +/- 36 to 115 +/- 62%. Of the 29 patients who were incontinent 3 (10%) achieved continence and 19 (65%) reported a decreased use of sanitary pads. None of the patients had systemic side effects related to intravesical treatment. CONCLUSIONS: We believe that intravesical oxybutynin chloride is a viable treatment option for patients with myelodysplasia in whom oral therapy fails.     

Percentage discounts, initial price, and bargain hunting: A heuristic-systematic approach to price search behavior.

Consumer decisions concerning price search were investigated using the heuristic-systematic model of social judgment (S. Chaiken, A. Liberman, & A. H. Eagly, 1989). Consumers used the size of the percentage discount as a heuristic cue to help decide whether a better price was likely to be available elsewhere. However, as predicted, participants relied on this cue only when the initial base price of the item was low. In contrast, search was continued despite the offer of a large percentage discount when consumers were shopping for items that were relatively expensive. This finding was attributed to the higher potential costs associated with missing a better price when consumers were shopping for more expensive items. In general, the heuristic-systematic model proved to be a useful way to characterize price search decisions. It was also suggested that these findings might be useful in explaining some conflicting results in the price search literature. Implications for behavioral price theories are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)