Effects of training multiple form classes on acquisition,generalization and maintenance of word retrieval in a single subject

Abstract

A study by McNeil et al. reported no generalization effects in two individuals with aphasia following application of a word finding treatment in which subjects were trained sequentially on lexical items arranged by form class. The present investigation examined, in one of the two subjects from the original study, whether training on lexical items from a variety of form classes concurrently would result in greater response generalization than was observed previously in this subject. Results replicated earlier findings with positive acquisition and maintenance effects and little evidence of generalization to untrained items within or across form classes.     

Excitatory actions of GABA in developing chick vestibular afferents: Effects on resting electrical activity

The aim of this study was to characterize the effect of γ-aminobutyric acid (GABA) in the resting multiunit activity of the vestibular afferents during development using the isolated inner ear of embryonic and postnatal chickens (E15-E21 and P5). GABA (10⁻³ to 10⁻⁵ M; n = 133) and muscimol (10⁻³M) elicited an increase in the frequency of the basal discharge of the vestibular afferents. We found that GABA action was dose-dependent and inversely related to animal age. Thus, the largest effect was observed in embryonic ages such as E15 and E17 and decreases in E21 and P5. The GABA_A receptor antagonists, bicuculline (10⁻⁵M; n = 10) and picrotoxin (10⁻⁴M; n = 10), significantly decreased the excitatory action of GABA and muscimol (10⁻³M). Additionally, CNQX 10⁻⁶M, MCPG 10⁻⁵M and 7ClKyn 10⁻⁵M (n = 5) were co-applied by bath substitution (n = 5). Both the basal discharge and the GABA action significantly decreased in these experimental conditions. The chloride channel blocker 9-AC 0.5 mM produced an important reduction in the effect of GABA 10⁻³ (n = 5) and 10⁻⁴M (n = 5). Thus, our results suggest an excitatory role of GABA in the resting activity of the vestibular afferents that can be explained by changes in the gradient of concentration of Cl⁻ during development. We show for the first time that the magnitude of this GABA effect decreases at later stages of embryonic and early postnatal development. Taking into account the results with glutamatergic antagonists, we conclude that GABA has a presynaptic action but is not the neurotransmitter in the vestibular afferent synapses, although it could act as a facilitator of the spontaneous activity and may regulate glutamate release. Synapse 67:374–381, 2013. © 2013 Wiley Periodicals, Inc.     

The influence of master cast technique on the cast precision of implant-retained fixed prostheses

The aim of this study was to evaluate the precision of three different mold filling techniques in order to obtain a cast simulating a three-unit, implant-retained, fixed prosthesis. Thirty casts (n = 10) were obtained using three different mold filling techniques. Group 1 used a unique fulfillment technique, Group 2 used a two-step fulfillment technique, and Group 3 used a latex cylinder technique. Using a metallic matrix, a titanium substructure was created to simulate a three-unit fixed prosthesis used as reference to evaluate the marginal misfit and tension forces in each cast. The vertical misfit was measured by an optical microscope with an increase of 120X and by an analysis unit using the one-screw test. The tension was quantified using strain gauges. The strain results showed a statistical difference between Group 3 and the other groups. The Tukey test showed no difference between the different treatment groups (p = 0.05). All three techniques were deemed efficient; however, considering that the cylinder latex technique induced less force toward the implants, it is the preferable technique for daily clinical practice.     

Relationships Between Health Care Disparities and Coverage Policies for Breast,Colon, and Lung Cancer Screening

Disparities in outcomes exist for breast, colon, and lung cancer among diverse populations, particularly racial and ethnic underrepresented minorities (URMs) and individuals from lower socioeconomic status. For example, blacks experience mortality rates up to about 42% higher than whites for these cancers. Furthermore, although overall death rates have been declining, the differential access to screening and care has aggravated disparities. Our purpose is to assess how the coverage policies of CMS and the United States Preventive Services Task Force (USPSTF) influence these disparities. Additionally, barriers are often encountered in accessing screening tests and receiving prompt treatment. To narrow, and potentially eliminate, outcomes disparities, CMS and USPSTF could consider revising their decision-making processes regarding coverage. Some options include (1) extending their evidence base to include observational studies that involve groups at higher risk; (2) lowering the threshold ages for screening to encompass differences in incidence; (3) CMS approving screening CT colonography coverage, which can even increase compliance with other screening tests; (4) clarifying and streamlining guidelines; (5) supporting research on improving access to screening; and (6) encouraging the development of more navigation services for URMs.     

Temporal Trends in Imaging Utilization for Suspected Substance Use Disorder in an Academic Emergency Radiology Department

PurposeTo assess temporal trends and utilization patterns of diagnostic imaging performed for substance use disorder (SUD)-related indications in an academic radiology emergency department (ED).MethodsRetrospective analyses of ED imaging examinations acquired from 2005 to 2015 were performed. Imaging examinations performed for suspected SUD-related indications, based on the order history, were compared with those without a SUD-related indication. Unadjusted analyses comparing demographic and imaging characteristics between SUD-related versus non-SUD-related indications used Wilcoxon and Pearson’s χ² tests. Multivariable logistic regression models, within each imaging modality subgroup and combined, were employed to examine the odds of imaging examinations having an SUD-related indication as a function of demographic and imaging characteristics.ResultsAmong 938,245 examinations, 0.17% had an SUD-related indication. Patients with SUD-related indications were younger (mean 37.2 ± 11.1 versus 53.5 ± 22.4, P < .001) and more commonly male (65% versus 52%, P < .001). The proportions of MR (17%), spine (17%), and extremities (33%) studies performed for SUD-related indications were larger among SUD than non-SUD indications (6%, 8%, 26%, respectively, all P < .001). Regression analysis demonstrated the odds of acquiring an ED imaging examination with an SUD-related indication significantly increased over time (P < .001, adjusted odds ratio [aOR] = 1.06), which was most pronounced among MR (P < .001, aOR = 1.23). For all regression models, younger age, male gender, and body part being imaged were identified as independent predictors of an SUD-related indication for ED imaging.ConclusionImaging performed for an SUD-related indication represented a small but increasing subset of overall ED imaging. Utilization of MR for SUD-related indications significantly outpaced growth of MR without SUD-related indications.