VA Palo Alto Healthcare System

About: VA Palo Alto Healthcare System is a healthcare organization based out in Palo Alto, California, United States. It is known for research contribution in the topics: Population & Health care. The organization has 2548 authors who have published 4605 publications receiving 209938 citations.

σ54 enhancer binding proteins and Myxococcus xanthus fruiting body development

Abstract: A search of the M1genome sequence, which includes 97% of the Myxococcus xanthus genes, identified 53 sequence homologs of 54 -dependent enhancer binding proteins (EBPs). A DNA microarray was constructed from the M1genome that includes those homologs and 318 other M. xanthus genes for comparison. To screen the developmental program with this array, an RNA extract from growing cells was compared with one prepared from developing cells at 12 h. Previous reporter studies had shown that M. xanthus has initiated development and has begun to express many developmentally regulated genes by 12 h. The comparison revealed substantial increases in the expression levels of 11 transcription factors that may respond to environmental stimuli. Six of the 53 EBP homologs were expressed at significantly higher levels at 12 h of development than during growth. Three were previously unknown genes, and they were inactivated to look for effects on fruiting body development. One knockout mutant produced fruiting bodies of abnormal shape that depended on the composition of the medium.

Averaging Different Alignment Axes Improves Femoral Rotational Alignment in Computer-Navigated Total Knee Arthroplasty

Abstract: Background: Computer navigation systems generally establish the rotational alignment axis of the femoral component on the basis of user-defined anatomic landmarks. However, navigation systems can also record knee kinematics and average alignment axes established with multiple techniques. We hypothesized that establishing femoral rotational alignment with the use of kinematic techniques is more accurate and precise (repeatable) than the use of anatomic techniques and that establishing femoral rotational alignment by averaging the results of different alignment techniques is more accurate and precise than the use of a single technique. Methods: Twelve orthopaedic surgeons used three anatomic and two kinematic alignment techniques to establish femoral rotational alignment axes in a series of nine cadaver knees. The axes derived with the individual anatomic and kinematic techniques as well as the axes derived with six combination techniques—i.e., those involving averaging of the alignments established with two of the individual techniques—were compared against a reference axis established with computed tomography images of each femur. Results: The kinematic methods were not more accurate (did not have smaller mean errors) or more precise (repeatable) than the anatomic techniques. The combination techniques were accurate (five of the six had a mean error of <5) and significantly more precise than all but one of the single methods. The percentage of measurements with <5 of error as compared with the reference epicondylar axis was 37% for the individual anatomic techniques, 30% for the individual kinematic techniques, and 58% for the combination techniques. Conclusions: Averaging the results of kinematic and anatomic techniques, which is possible with computer navigation systems, appears to improve the accuracy of rotational alignment of the femoral component. The number of rotational alignment outliers was reduced when combination techniques were used; however, they are still a problem and continued improvement in methods to accurately establish rotation of the femoral component in total knee arthroplasty is needed.

Giving context to post-deployment post-concussive-like symptoms: blast-related potential mild traumatic brain injury and comorbidities.

Abstract: In the military and Veterans Administration systems, individuals with potential MTBI are presenting with symptoms in excess of what would be expected based on initial injury characteristics and/or at unexpected time periods based on current research findings. This article investigates factors that might account for the discrepancy between current research expectations and some occurrences in clinical practice. The physics of blast waves, as well as animal and human research, relevant to explosions are reviewed. Additional factors that occur within the military blast exposure milieu are also explored because the context in which an injury occurs can potentially impact symptom severity and course of recovery. Differential diagnoses, iatrogenic illness, diagnosis threat, and symptom embellishment are also considered.

Cognitive control network anatomy correlates with neurocognitive behavior: A longitudinal study

Abstract: Cognitive control is the process of employing executive functions, such as attention, planning or working memory, to guide appropriate behaviors in order to achieve a specific goal. Functional magnetic resonance imaging studies suggest a superordinate cognitive control network, comprising the dorsal regions of the lateral prefrontal cortex (DLPFC), anterior cingulate cortex (dACC) and parietal cortex (DPC). How gray matter structure changes across this network throughout neurodevelopment and how these changes impact cognitive control are not yet fully understood. Here we investigate changes in gray matter volume of the key nodes of the cognitive control network using structural MRI scans from 176 participants aged 8-38 years. One hundred and eleven of these also completed a longitudinal follow-up at two years. We compare these with performance on a cognitive battery also measured at these two time points. We found that volume decreases in the cognitive control network were associated with improved performance in executive function (in left DLPFC and bilateral DPC), information processing (in bilateral dACC and right DPC) and emotion identification tasks (left DLPFC). These results were significant after controlling for age. Furthermore, gray matter changes were coordinated across the network. These findings imply age-independent synaptic pruning in the cognitive control network may have a role in improving performance in cognitive domains. This study provides insight into the direct impact of structural changes on behavior within this network during neurodevelopment and provides a normative evidence base to better understand development of cognitive dysfunction in brain disorders. Hum Brain Mapp 38:631-643, 2017. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

The impact of exercise on suicide risk: examining pathways through depression, PTSD, and sleep in an inpatient sample of veterans.

Abstract: Suicide has a large public health impact. Although effective interventions exist, the many people at risk for suicide cannot access these interventions. Exercise interventions hold promise in terms of reducing suicide because of their ease of implementation. While exercise reduces depression, and reductions in depressive symptoms are linked to reduced suicidal ideation, no studies have directly linked exercise and suicide risk. The current study examined this association, including potential mediators (i.e., sleep disturbance, posttraumatic stress symptoms, and depression), in a sample of Veterans. SEM analyses revealed that exercise was directly and indirectly associated with suicide risk. Additionally, exercise was associated with fewer depressive symptoms and better sleep patterns, each of which was, in turn, related to lower suicide risk.