Stochastic dynamic causal modeling of working memory connections in cocaine dependence

Although reduced working memory brain activation has been reported in several brain regions of cocaine‐dependent subjects compared with controls, very little is known about whether there is altered connectivity of working memory pathways in cocaine dependence. This study addresses this issue by using functional magnetic resonance imaging‐based stochastic dynamic causal modeling (DCM) analysis to study the effective connectivity of 19 cocaine‐dependent subjects and 14 healthy controls while performing a working memory task. Stochastic DCM is an advanced method that has recently been implemented in SPM8 that can obtain improved estimates, relative to deterministic DCM, of hidden neuronal causes before convolution with the hemodynamic response. Thus, stochastic DCM may be less influenced by the confounding effects of variations in blood oxygen level‐dependent response caused by disease or drugs. Based on the significant regional activation common to both groups and consistent with previous working memory activation studies, seven regions of interest were chosen as nodes for DCM analyses. Bayesian family level inference, Bayesian model selection analyses, and Bayesian model averaging (BMA) were conducted. BMA showed that the cocaine‐dependent subjects had large differences compared with the control subjects in the strengths of prefrontal–striatal modulatory (B matrix) DCM parameters. These findings are consistent with altered cortical–striatal networks that may be related to reduced dopamine function in cocaine dependence. As far as we are aware, this is the first between‐group DCM study using stochastic methodology. Hum Brain Mapp 35:760–778, 2014. © 2012 Wiley Periodicals, Inc.     

Penetration of latamoxef, cefoperazone and piperacillin into the sputum of patients with cystic fibrosis

Concentrations of latamoxef, cefoperazone and piperacillin, administered intravenously, were measured in serum and sputum of cystic fibrosis patients with recurrent pulmonary infections, chronically colonized with Pseudomonas aeruginosa. Serum pharmacokinetic data were consistent with prior reports. Peak sputum to peak serum concentrations were approximately 3% for each antimicrobial. However, the more prolonged sputum concentrations of piperacillin were reflected in greater areas under the sputum concentration-time curve and a longer duration above the MIC50 of tested P. aeruginosa strains for that drug.     

Risk factors for postoperative seizures in patients with chronic subdural haematomas

Neurosurgical Review - Postoperative seizures are a frequently occurring yet not well-understood complication in patients undergoing surgical treatment of chronic subdural haematomas (cSDHs)....     

Longitudinal invariance and construct validity of the abbreviated late-life function and disability instrument in healthy older adults

Szabo AN, Mullen SP, White SM, Wojcicki TR, Mailey EL, Gothe N, Olson EA, Fanning J, Kramer AF, McAuley E. Longitudinal invariance and construct validity of the abbreviated Late-Life Function and Disability Instrument in healthy older adults.

Objective

To cross-validate the psychometric properties of the abbreviated Late-Life Function and Disability Instrument (LL-FDI), a measure of perceived functional limitations and disability.

Design

Baseline and 12-month follow-up assessments conducted across the course of a 12-month exercise program.

Setting

University research community.

Participants

Older healthy adults (N=179; mean ± SD age, 66.43±5.67y) at baseline; 145 were retained at follow-up.

Interventions

Not applicable.

Main Outcome Measures

LL-FDI and functional performance measures.

Results

Factor analyses confirmed the factor structure of the abbreviated LL-FDI, and all subscales met minimal criteria for temporal invariance. Significant correlations also were found between functional limitations subscales and an array of physical function performance measures, supporting the scale's construct validity.

Conclusions

The abbreviated LL-FDI with some modifications appears to be temporally invariant in community-dwelling older adults. Additionally, moderate relationships between functional limitations and functional performance provide further support for these being conceptually distinct constructs.     

Frequence,Spectrum and Prognostic Impact of Additional Malignancies in Patients With Gastrointestinal Stromal Tumors

Currently available data on prognostic implication of additional neoplasms in GIST miss comprehensive information on patient outcome with regard to overall or disease specific and disease free survival. Registry data of GIST patients with and without additional neoplasm were compared in retrospective case series. We investigated a total of 836 patients from the multi-center Ulmer GIST registry. Additionally, a second cohort encompassing 143 consecutively recruited patients of a single oncology center were analyzed. The frequency of additional malignant neoplasms in GIST patients was 31.9% and 42.0% in both cohorts with a mean follow-up time of 54 and 65 months (median 48 and 60 months), respectively. The spectrum of additional neoplasms in both cohorts encompasses gastrointestinal tumors (43.5%), uro-genital and breast cancers (34.1%), hematological malignancies (7.3%), skin cancer (7.3%) and others. Additional neoplasms have had a significant impact on patient outcome. The five year overall survival in GIST with additional malignant neoplasms (n = 267) was 62.8% compared to 83.4% in patients without other tumors (n = 569) (P < .001, HR=0.397, 95% CI: 0.298-0.530). Five-year disease specific survival was not different between both groups (90.8% versus 90.9%). 34.2% of all deaths (n = 66 of n = 193) were GIST-related. The presented data suggest a close association between the duration of follow-up and the rate of additional malignancies in GIST patients. Moreover the data indicate a strong impact of additional malignant neoplasms in GIST on patient outcome. A comprehensive follow-up strategy of GIST patients appears to be warranted.