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Martinez VA Medical Center

Hospital / health systemMartinez, California, United States

Research output, citation impact, and the most-cited recent papers from Martinez VA Medical Center (United States). Aggregated across the NobleBlocks index of 300M+ scholarly works.

Total works
1.4K
Citations
107.4K
h-index
157
i10-index
1.4K
Also known as
Martinez VA Medical Center

Top-cited papers from Martinez VA Medical Center

Shifting visual attention between objects and locations: Evidence from normal and parietal lesion subjects.
Robert Egly, Jon Driver, Robert D. Rafal
1994· Journal of Experimental Psychology General1.0Kdoi:10.1037//0096-3445.123.2.161

Space- and object-based attention components were examined in neurologically normal and parietal-lesion subjects, who detected a luminance change at 1 of 4 ends of 2 outline rectangles. One rectangle end was precued (75% valid); on invalid-cue trials, the target appeared at the other end of the cued rectangle or at 1 end of the uncued rectangle. For normals, the cost for invalid cues was greater for targets in the uncued rectangle, indicating an object-based component. Both right- and left-hemisphere patients showed costs that were greater for contralesional targets. For right-hemisphere patients, the object cost was equivalent for contralesional and ipsilesional targets, indicating a spatial deficit, whereas the object cost for left-hemisphere patients was larger for contralesional targets, indicating an object deficit.

Phage treatment of human infections
Stephen T. Abedon, Sarah J. Kuhl, Bob Blasdel, Elizabeth Kutter
2011· Bacteriophage970doi:10.4161/bact.1.2.15845

Phages as bactericidal agents have been employed for 90 years as a means of treating bacterial infections in humans as well as other species, a process known as phage therapy. In this review we explore both the early historical and more modern use of phages to treat human infections. We discuss in particular the little-reviewed French early work, along with the Polish, US, Georgian and Russian historical experiences. We also cover other, more modern examples of phage therapy of humans as differentiated in terms of disease. In addition, we provide discussions of phage safety, other aspects of phage therapy pharmacology, and the idea of phage use as probiotics.

Cortical Networks Underlying Mechanisms of Time Perception
Deborah L. Harrington, Kathleen Y. Haaland, Robert T. Knight
1998· Journal of Neuroscience564doi:10.1523/jneurosci.18-03-01085.1998

Precise timing of sensory information from multiple sensory streams is essential for many aspects of human perception and action. Animal and human research implicates the basal ganglia and cerebellar systems in timekeeping operations, but investigations into the role of the cerebral cortex have been limited. Individuals with focal left (LHD) or right hemisphere (RHD) lesions and control subjects performed two time perception tasks (duration perception, wherein the standard tone pair interval was 300 or 600 msec) and a frequency perception task, which controlled for deficits in time-independent processes shared by both tasks. When frequency perception deficits were controlled, only patients with RHD showed time perception deficits. Time perception competency was correlated with an independent test of switching nonspatial attention in the RHD but not the LHD patients, despite attention deficits in both groups. Lesion overlays of patients with RHD and impaired timing showed that 100% of the patients with anterior damage had lesions in premotor and prefrontal cortex (Brodmann areas 6, 8, 9, and 46), and 100% with posterior damage had lesions in the inferior parietal cortex. All LHD patients with normal timing had damage in these same regions, whereas few, if any, RHD patients with normal timing had similar lesion distributions. These results implicate a right hemisphere prefrontal-inferior parietal network in timing. Time-dependent attention and working memory functions may contribute to temporal perception deficits observed after damage to this network.

The Cerebellum and Event Timing
Richard B. Ivry, Rebecca M. C. Spencer, Howard N. Zelaznik, Jörn Diedrichsen
2002· Annals of the New York Academy of Sciences523doi:10.1111/j.1749-6632.2002.tb07576.x

Damage to the cerebellum disrupts performance on a range of tasks that require precise timing including the production of skilled movements, eyeblink conditioning, and perceptual tasks such as duration discrimination. We hypothesize that such tasks involve event timing, a form of representation in which the temporal goals are explicitly represented. For example, during finger tapping, the goal to produce evenly paced intervals invokes an explicit temporal representation of the time between successive contact points with the tapping surface. In contrast, timing can be an emergent property in other actions, reflecting temporal consistencies that arise through the control of other movement parameters. One example is continuous circle drawing, a task in which temporal consistency can be achieved by maintaining a constant angular velocity or minimizing higher-order derivatives (e.g., jerk). Temporal consistency on event and emergent timing tasks is not correlated and patients with cerebellar damage show no increase in temporal variability during continuous circle drawing. While the cerebellum likely contributes to performance of a wide range of skilled behaviors, it appears to be especially important when the tasks entail event timing.

Verb generation in patients with focal frontal lesions: A neuropsychological test of neuroimaging findings
Sharon L. Thompson‐Schill, Diane Swick, Martha J. Farah, Mark D’Esposito +2 more
1998· Proceedings of the National Academy of Sciences488doi:10.1073/pnas.95.26.15855

What are the neural bases of semantic memory? Traditional beliefs that the temporal lobes subserve the retrieval of semantic knowledge, arising from lesion studies, have been recently called into question by functional neuroimaging studies finding correlations between semantic retrieval and activity in left prefrontal cortex. Has neuroimaging taught us something new about the neural bases of cognition that older methods could not reveal or has it merely identified brain activity that is correlated with but not causally related to the process of semantic retrieval? We examined the ability of patients with focal frontal lesions to perform a task commonly used in neuroimaging experiments, the generation of semantically appropriate action words for concrete nouns, and found evidence of the necessity of the left inferior frontal gyrus for certain components of the verb generation task. Notably, these components did not include semantic retrieval per se.

Neural Origins of the P300
Maryam Soltani, Robert T. Knight
2000· Critical Reviews in Neurobiology430doi:10.1615/critrevneurobiol.v14.i3-4.20

A review of the literature investigating the neural origins of detection behavior in humans reveals two event-related potential components, P3a and P3b, each with a distinct neural organization and cognitive function.The P3a is involved in automatic novelty detection and characterized by a more anterior cortical distribution, whereas the P3b is concerned with volitional target detection and has a more posterior cortical distribution. Intracranial investigation, studies with patients with focal brain lesions, and functional neuroimaging (fMRI) studies converge with scalp-recorded event-related potential (ERP) data in suggesting that a widespread cortical network gives rise to both automatic and controlled detection behavior. The main regions consistently attributed to generating detection-related brain activation include the temporal-parietal junction, medial temporal complex, and the lateral prefrontal cortex. The extant human and animal literature addressing the neural networks, neuropharmacological underpinnings, and behavioral significance of the P300 potential will be reviewed.

Lifestyle recommendations for the prevention and management of metabolic syndrome: an international panel recommendation
Pablo Pérez‐Martínez, Dimitri P. Mikhailidis, Vasilios G. Athyros, Mònica Bulló +4 more
2017· Nutrition Reviews413doi:10.1093/nutrit/nux014

The importance of metabolic syndrome (MetS) lies in its associated risk of cardiovascular disease and type 2 diabetes, as well as other harmful conditions such as nonalcoholic fatty liver disease. In this report, the available scientific evidence on the associations between lifestyle changes and MetS and its components is reviewed to derive recommendations for MetS prevention and management. Weight loss through an energy-restricted diet together with increased energy expenditure through physical activity contribute to the prevention and treatment of MetS. A Mediterranean-type diet, with or without energy restriction, is an effective treatment component. This dietary pattern should be built upon an increased intake of unsaturated fat, primarily from olive oil, and emphasize the consumption of legumes, cereals (whole grains), fruits, vegetables, nuts, fish, and low-fat dairy products, as well as moderate consumption of alcohol. Other dietary patterns (Dietary Approaches to Stop Hypertension, new Nordic, and vegetarian diets) have also been proposed as alternatives for preventing MetS. Quitting smoking and reducing intake of sugar-sweetened beverages and meat and meat products are mandatory. Nevertheless, there are inconsistencies and gaps in the evidence, and additional research is needed to define the most appropriate therapies for MetS. In conclusion, a healthy lifestyle is critical to prevent or delay the onset of MetS in susceptible individuals and to prevent cardiovascular disease and type 2 diabetes in those with existing MetS. The recommendations provided in this article should help patients and clinicians understand and implement the most effective approaches for lifestyle change to prevent MetS and improve cardiometabolic health.

Emotional facial expressions capture attention
Patrik Vuilleumier, Sophie Schwartz
2001· Neurology368doi:10.1212/wnl.56.2.153

OBJECTIVE: To determine whether the emotional significance of stimuli can influence spatial attention. BACKGROUND: Motivational and emotional factors may affect attention toward stimuli. However, this has never been examined in brain-damaged patients who present with unilateral inattention due to left spatial neglect. METHODS: The authors studied three patients with chronic left neglect and visual extinction after right parietal stroke. Shapes or faces with neutral, happy, or angry expressions were briefly presented in the right, left, or both visual fields. On unilateral trials, the patients detected all stimuli equally on both sides. On bilateral trials, they extinguished faces in the contralesional field much less often than shapes, and faces with happy or angry facial expressions much less than faces with a neutral expression. CONCLUSION: Facial features and emotional expressions can be analyzed despite lying on the unattended side, and may influence the spatial distribution of attention. These findings support the view that attention is controlled by neural mechanisms involving not only frontoparietal areas but also limbic components in cingulate cortex and amygdala, which may interact with ventral visual areas in the temporal lobe to detect affective value and prioritize attention to salient stimuli.

A Randomized Trial of Epidural Glucocorticoid Injections for Spinal Stenosis
Janna Friedly, Bryan A. Comstock, Judith A. Turner, Patrick J. Heagerty +4 more
2014· New England Journal of Medicine367doi:10.1056/nejmoa1313265

BACKGROUND: Epidural glucocorticoid injections are widely used to treat symptoms of lumbar spinal stenosis, a common cause of pain and disability in older adults. However, rigorous data are lacking regarding the effectiveness and safety of these injections. METHODS: In a double-blind, multisite trial, we randomly assigned 400 patients who had lumbar central spinal stenosis and moderate-to-severe leg pain and disability to receive epidural injections of glucocorticoids plus lidocaine or lidocaine alone. The patients received one or two injections before the primary outcome evaluation, performed 6 weeks after randomization and the first injection. The primary outcomes were the score on the Roland-Morris Disability Questionnaire (RMDQ, in which scores range from 0 to 24, with higher scores indicating greater physical disability) and the rating of the intensity of leg pain (on a scale from 0 to 10, with 0 indicating no pain and 10 indicating "pain as bad as you can imagine"). RESULTS: At 6 weeks, there were no significant between-group differences in the RMDQ score (adjusted difference in the average treatment effect between the glucocorticoid-lidocaine group and the lidocaine-alone group, -1.0 points; 95% confidence interval [CI], -2.1 to 0.1; P=0.07) or the intensity of leg pain (adjusted difference in the average treatment effect, -0.2 points; 95% CI, -0.8 to 0.4; P=0.48). A prespecified secondary subgroup analysis with stratification according to type of injection (interlaminar vs. transforaminal) likewise showed no significant differences at 6 weeks. CONCLUSIONS: In the treatment of lumbar spinal stenosis, epidural injection of glucocorticoids plus lidocaine offered minimal or no short-term benefit as compared with epidural injection of lidocaine alone. (Funded by the Agency for Healthcare Research and Quality; ClinicalTrials.gov number, NCT01238536.).

Quantitative NMR measurements of hippocampal atrophy in Alzheimer's disease
J. Philip Seab, William J. Jagust, Tak‐sum Wong, M.S. Roos +2 more
1988· Magnetic Resonance in Medicine363doi:10.1002/mrm.1910080210

Nuclear magnetic resonance (NMR) imaging was employed to study 10 patients with Alzheimer's disease (AD) and seven healthy elderly control subjects. Coronal sections were used to make volumetric measurements of the hippocampus, ventricles, subarachnoid space, and brain parenchyma. The hippocampal volume (normalized relative to the size of the lenticular nucleus) was reduced by 40% in the AD group compared to the controls, with no overlap between the two groups. Overall measures of brain atrophy and ventricular and sulcal enlargement also showed significantly different group means, although with overlap between the two groups. Hippocampal atrophy did not correlate with either overall brain atrophy or dementia severity, although the degree of brain atrophy was correlated with dementia severity. These results show that NMR is capable of providing in vivo quantification of diminished hippocampal size in AD which is not correlated with overall brain atrophy and which may differentiate AD from normal aging.

Liver disease induced by radioembolization of liver tumors
Bruno Sangro, Belén Gil-Alzugaray, Javier Rodríguez, Iosu Sola +4 more
2008· Cancer362doi:10.1002/cncr.23339

BACKGROUND: To the authors' knowledge, liver damage after liver radioembolization with yttrium90-labeled microspheres has never been studied specifically. METHODS: Using a complete set of data recorded prospectively among all patients without previous chronic liver disease treated by radioembolization at the authors' institution from September 2003 to July 2006, patterns of liver damage were identified and possible risk factors were analyzed. RESULTS: In all, 20% of patients developed a distinct clinical picture that appeared 4 to 8 weeks after treatment and was characterized by jaundice and ascites. Veno-occlusive disease was the histologic hallmark observed in the most severe cases. This form of sinusoidal obstruction syndrome was not observed among patients who never received chemotherapy or in those in whom a single hepatic lobe was treated. Relevant to treatment planning, a possible risk factor was a higher treatment dose in relation to the targeted liver volume. A transjugular intrahepatic stent shunt improved liver function in 2 patients with impending liver failure, although 1 of them eventually died from it. CONCLUSIONS: Radioembolization of liver tumors, particularly after antineoplastic chemotherapy, may result in an uncommon but potentially life-threatening form of hepatic sinusoidal obstruction syndrome that presents clinically with jaundice and ascites.

MCCCS Towhee: a tool for Monte Carlo molecular simulation
Marcus G. Martin
2013· Molecular Simulation348doi:10.1080/08927022.2013.828208

The history of the Monte Carlo for complex chemical systems Towhee open source Monte Carlo molecular simulation tool is discussed. A proof is given that the Widom insertion method for computing the chemical potential is formally correct even when combined with the most general version of arbitrary trial distribution configurational-bias Monte Carlo. A simulation strategy for computing single component vapour–liquid phase coexistence curves is presented as a guide for inexperienced practitioners of Monte Carlo simulations. A review of papers that cite the Towhee code is presented. The paper concludes with a discussion about releasing and sustaining a simulation package that uses an open source software license.

2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary
Steve R. Ommen, Seema Mital, Michael A. Burke, Sharlene M. Day +4 more
2020· Circulation312doi:10.1161/cir.0000000000000938

Aim This executive summary of the hypertrophic cardiomyopathy clinical practice guideline provides recommendations and algorithms for clinicians to diagnose and manage hypertrophic cardiomyopathy in adult and pediatric patients as well as supporting documentation to encourage their use. Methods A comprehensive literature search was conducted from January 1, 2010, to April 30, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Structure Many recommendations from the earlier hypertrophic cardiomyopathy guidelines have been updated with new evidence or a better understanding of earlier evidence. This summary operationalizes the recommendations from the full guideline and presents a combination of diagnostic work-up, genetic and family screening, risk stratification approaches, lifestyle modifications, surgical and catheter interventions, and medications that constitute components of guideline directed medical therapy. For both guideline-directed medical therapy and other recommended drug treatment regimens, the reader is advised to follow dosing, contraindications and drug-drug interactions based on product insert materials.

Anatomic Bases of Event-Related Potentials and Their Relationship to Novelty Detection in Humans
Robert T. Knight, Donatella Scabini
1998· Journal of Clinical Neurophysiology301doi:10.1097/00004691-199801000-00003

Department of Neurology, Center for Neuroscience, University of California, Davis, Veterans Medical Center, Martinez, California, U.S.A. Address correspondence and reprint requests to Dr. Robert T. Knight, Department of Neurology, Center for Neuroscience, University of California, Davis, Veterans Medical Center, 150 Muir Rd., Martinez, CA 94553, U.S.A.

Duodenal and Gastric Ulcer Prevention with Misoprostol in Arthritis Patients Taking NSAIDs
David Y. Graham, Richard H. White, Larry W. Moreland, Timothy T. Schubert +4 more
1993· Annals of Internal Medicine297doi:10.7326/0003-4819-119-4-199308150-00001

OBJECTIVES: To determine the efficacy of misoprostol for the prevention of nonsteroidal anti-inflammatory drug (NSAID)-induced duodenal and gastric ulcers in arthritis patients receiving NSAID therapy. DESIGN: A randomized, double-blind, multicenter, placebo-controlled trial. SETTING: Six hundred thirty-eight private, Veterans Affairs, health maintenance, and academic practices. PATIENTS: Six hundred thirty-eight patients with chronic inflammatory or noninflammatory arthritis who were taking an NSAID but who did not have a gastric or duodenal ulcer on screening endoscopy received treatment with ibuprofen, piroxicam, naproxen, sulindac, tolmetin, indomethacin, or diclofenac daily for 3 months. Four hundred fifty-five (71%) patients completed the trial. INTERVENTIONS: Patients meeting the entry criteria were randomized to receive either misoprostol, 200 micrograms, or placebo, four times a day for 12 weeks. MAIN OUTCOME MEASURES: The endoscopy was repeated at 4, 8, and 12 weeks. The development of a duodenal or gastric ulcer (defined as a circumscribed mucosal defect > or = 0.5 cm in diameter and with perceptible depth) was regarded as prophylactic failure. RESULTS: By 12 weeks, a duodenal ulcer developed in 2 of 320 (0.6%; 95% CI, 0.2% to 3.9%) patients randomized to receive misoprostol, compared with 15 of 323 (4.6%; CI, 2.8% to 8%) patients receiving placebo (P = 0.002). A gastric ulcer developed in 6 of 320 (1.9%; (CI, 0.8% to 4.4%) patients, compared with in 25 of 323 (7.7%; CI, 5.1% to 11.4%), respectively. CONCLUSION: Misoprostol significantly lowers the frequency of both duodenal and gastric ulcer development in patients who require long-term therapy with NSAIDS.

Selective impairment of reasoning about social exchange in a patient with bilateral limbic system damage
Valerie E. Stone, Leda Cosmides, John Tooby, Neal E. A. Kroll +1 more
2002· Proceedings of the National Academy of Sciences277doi:10.1073/pnas.122352699

Social exchange is a pervasive feature of human social life. Models in evolutionary biology predict that for social exchange to evolve in a species, individuals must be able to detect cheaters (nonreciprocators). Previous research suggests that humans have a cognitive mechanism specialized for detecting cheaters. Here we provide neurological evidence indicating that social exchange reasoning can be selectively impaired while reasoning about other domains is left intact. The patient, R.M., had extensive bilateral limbic system damage, affecting orbitofrontal cortex, temporal pole, and amygdala. We compared his performance on two types of reasoning problem that were closely matched in form and equally difficult for control subjects: social contract rules (of the form, "If you take the benefit, then you must satisfy the requirement") and precaution rules (of the form, "If you engage in hazardous activity X, then you must take precaution Y"). R.M. performed significantly worse in social contract reasoning than in precaution reasoning, when compared both with normal controls and with other brain-damaged subjects. This dissociation in reasoning performance provides evidence that reasoning about social exchange is a specialized and separable component of human social intelligence, and is consistent with other research indicating that the brain processes information about the social world differently from other types of information.

Experimental Models of Hepatic Fibrosis: A Review
Hidekazu Tsukamoto, Masaki Matsuoka, Samuel W. French
1990· Seminars in Liver Disease270doi:10.1055/s-2008-1040457

No experimental model reproduces exactly human liver fibrosis by etiology. Nonetheless, each of the models reviewed in this article has served to enhance our understanding of pathogenetic mechanisms of liver fibrosis. There have been important common findings derived from several different models. The best example is the role of Ito cells in liver fibrogenesis. Involvement of Ito cells was consistently seen in the experimental models regardless of whether the fibrogenic stimulus was nutritional, hepatotoxic, or immunologic. Cellular and molecular mechanisms of Ito cell activation have begun to be explored in different models. Another example is the role of TGF beta in liver fibrogenesis. In both murine schistosomiasis model and Tsukamoto-French rat model, TGF beta was shown to be closely associated with fibrogenesis. With both in vitro and in vivo experimental approaches using cellular and molecular techniques, the experimental model of liver fibrosis will continue to provide data on the pathogenetic mechanisms of liver fibrogenesis. Future genetic and molecular approaches may allow development animal models with liver fibrosis that is inducible and genetically similarity to that of man.

Human prefrontal lesions increase distractibility to irrelevant sensory inputs
Linda L. Chao, Robert T. Knight
1995· Neuroreport269doi:10.1097/00001756-199508000-00005

Neurological patients with focal lesions in either the dorsolateral prefrontal cortex, temporal-parietal junction or the posterior hippocampus, and control subjects, were tested on a task requiring short-term retention of environmental sounds. Subjects had to indicate whether initial and subsequent test sounds were identical in two conditions. The initial and test sounds were separated by either a silent period varying from 4 to 12.6 s (no-distractor condition) or a series of irrelevant tones (distractor condition). Prefrontal patients were significantly impaired by distractors at all delays, hippocampal patients were impaired only at longer delays, while temporal-parietal patients performed similar to controls. The findings suggest that dorsolateral prefrontal cortex is crucial for gating of distracting information during delay tasks.

Distributed Cortical Network for Visual Attention
Robert T. Knight
1997· Journal of Cognitive Neuroscience258doi:10.1162/jocn.1997.9.1.75

The contribution of prefrontal and posterior association cortex to voluntary and involuntary visual attention was as sessed using electrophysiological techniques in patients with focal lesions in prefrontal (n = 11), temporal-parietal (n = 10), or lateral parietal cortex (n = 7). Subjects participated in a task requiring detection of designated target stimuli embedded in trains of repetitive stimuli. Infrequent and irrelevant novel visual stimuli were randomly interspersed with the target and background stimuli. Controls generated attention dependent N1 (170 msec) and N2 (243 msec) potentials maximal over extrastriate cortex. Anterior and posterior association cortex lesions reduced the amplitude of both the N1 and N2 potentials recorded over extrastriate cortex of the lesioned hemisphere. The pattern of results obtained reveals that an intrahemispheric network involving prefrontal and posterior association cortex modulates early visual processing in extrastriate regions. Voluntary target detection generated a parietal maximal P300 response (P3b) and irrelevant novel stimuli generated a more frontocentrally distributed P300 (P3a). Cortical lesions had differential effects on P3a and P3b potentials. The P3b was not significantly reduced in any cortical lesioned group. Conversely, the P3a was reduced by both prefrontal and posterior lesions with decrements most severe throughout the lesioned hemisphere. These data provide evidence that an association cortex network involving prefrontal and posterior regions is activated during orientation to novel events. The lack of a significant effect on the visual target P3b in patients with novelty P3a reductions supports the notion that different neural systems are engaged during voluntary vs involuntary atten- tion to visual stimuli.

Retrieval from semantic memory in Alzheimer-type dementia
Beth A. Ober, Nina F. Dronkers, Elisabeth Koss, Dean C. Delis +1 more
1986· Journal of clinical and experimental neuropsychology249doi:10.1080/01688638608401298

Retrieval from semantic memory, measured by tasks requiring subjects to name items from a given category, was studied in mild Alzheimer-type dementia (Mild-ATD) subjects, moderate-to-severe Alzheimer-type dementia (MS-ATD) subjects, and normal controls. Semantic retrieval performance was shown to be highly sensitive to both the presence and the severity of ATD. Retrieval from both semantic categories and letter categories showed differences in the rate of production of correct responses between subject groups. These rate differences were not due to differences in accessibility of low-dominance semantic category members or low-frequency letter category members. An increase in errors as well as a decrease in correct responses contributed to the performance deficits of the ATD subjects. Furthermore, the pattern of errors changed from Mild- to MS-ATD. Qualitative as well as quantitative differences were also observed in the performance of Mild- versus MS-ATD groups on a third type of semantic retrieval task--the supermarket task. As performance of the ATD subjects declined on these semantic retrieval tasks, so did their performance on other tasks assessing primarily attention, language, and memory. The findings are discussed in terms of the progressive breakdown in both attentional and semantic memory functions which are associated with ATD.