Michael bakey Va Medical Center

Houston, TX, United States

Michael bakey Va Medical Center

Houston, TX, United States
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Murrough J.W.,Mount Sinai School of Medicine | Perez A.M.,Mount Sinai School of Medicine | Pillemer S.,Mount Sinai School of Medicine | Stern J.,Mount Sinai School of Medicine | And 7 more authors.
Biological Psychiatry | Year: 2013

Background: Ketamine is reported to have rapid antidepressant effects; however, there is limited understanding of the time-course of ketamine effects beyond a single infusion. A previous report including 10 participants with treatment-resistant major depression (TRD) found that six ketamine infusions resulted in a sustained antidepressant effect. In the current report, we examined the pattern and durability of antidepressant effects of repeated ketamine infusions in a larger sample, inclusive of the original. Methods: Participants with TRD (n = 24) underwent a washout of antidepressant medication followed by a series of up to six IV infusions of ketamine (.5 mg/kg) administered open-label three times weekly over a 12-day period. Participants meeting response criteria were monitored for relapse for up to 83 days from the last infusion. Results: The overall response rate at study end was 70.8%. There was a large mean decrease in Montgomery-Åsberg Depression Rating Scale score at 2 hours after the first ketamine infusion (18.9 ± 6.6, p <.001), and this decrease was largely sustained for the duration of the infusion period. Response at study end was strongly predicted by response at 4 hours (94% sensitive, 71% specific). Among responders, median time to relapse after the last ketamine infusion was 18 days. Conclusions: Ketamine was associated with a rapid antidepressant effect in TRD that was predictive of a sustained effect. Future controlled studies will be required to identify strategies to maintain an antidepressant response among patients who benefit from a course of ketamine. © 2013 Society of Biological Psychiatry.


Chiang S.,Rice University | Cassese A.,Rice University | Cassese A.,University of Houston | Cassese A.,Maastricht University | And 7 more authors.
NeuroImage | Year: 2016

Brain graphs provide a useful way to computationally model the network structure of the connectome, and this has led to increasing interest in the use of graph theory to quantitate and investigate the topological characteristics of the healthy brain and brain disorders on the network level. The majority of graph theory investigations of functional connectivity have relied on the assumption of temporal stationarity. However, recent evidence increasingly suggests that functional connectivity fluctuates over the length of the scan. In this study, we investigate the stationarity of brain network topology using a Bayesian hidden Markov model (HMM) approach that estimates the dynamic structure of graph theoretical measures of whole-brain functional connectivity. In addition to extracting the stationary distribution and transition probabilities of commonly employed graph theory measures, we propose two estimators of temporal stationarity: the S-index and N-index. These indexes can be used to quantify different aspects of the temporal stationarity of graph theory measures. We apply the method and proposed estimators to resting-state functional MRI data from healthy controls and patients with temporal lobe epilepsy. Our analysis shows that several graph theory measures, including small-world index, global integration measures, and betweenness centrality, may exhibit greater stationarity over time and therefore be more robust. Additionally, we demonstrate that accounting for subject-level differences in the level of temporal stationarity of network topology may increase discriminatory power in discriminating between disease states. Our results confirm and extend findings from other studies regarding the dynamic nature of functional connectivity, and suggest that using statistical models which explicitly account for the dynamic nature of functional connectivity in graph theory analyses may improve the sensitivity of investigations and consistency across investigations. © 2015 Elsevier Inc.


Zhang X.Y.,Baylor College of Medicine | Zhang X.Y.,Michael bakey Va Medical Center | Zhang X.Y.,Peking University | Yao J.K.,Medical Research Service | Yao J.K.,University of Pittsburgh
Progress in Neuro-Psychopharmacology and Biological Psychiatry | Year: 2013

Increasing evidence indicates that disturbances of antioxidant defense system and presence of oxidative stress can play a part in a wide range of neuropsychiatric disorders, including schizophrenia, bipolar disorder, and major depression, as well as antipsychotic-induced tardive dyskinesia (TD). Moreover, researchers have embarked on using antioxidant treatment as adjunct therapy for psychiatry disorders. Evidence from clinical, pre-clinical and epidemiological studies suggests that a benefit of using antioxidant compounds should be considered as an adjunctive therapy in these patients. These are some of the main perspectives that are reviewed by four articles in this special section. Overall, there has been growing recognition of the importance of oxidative stress in the pathophysiology of psychiatric disorders and the development of TD. The collection of articles in this special section will contribute to providing more efficacious treatments arising from a better appreciation of the roles of oxidative stress in these psychiatric disorders. © 2013 Elsevier Inc.


Wu J.Q.,University of Newcastle | Wu J.Q.,Schizophrenia Research Institute | Wu J.Q.,Peking University | Kosten T.R.,Peking University | And 5 more authors.
Progress in Neuro-Psychopharmacology and Biological Psychiatry | Year: 2013

The etiopathogenic mechanisms of schizophrenia are to date unknown, although several hypotheses have been suggested. Accumulating evidence suggests that excessive free radical production or oxidative stress may be involved in the pathophysiology of schizophrenia as evidenced by increased production of reactive oxygen or decreased antioxidant protection in schizophrenic patients. This review aims to summarize the basic molecular mechanisms of free radical metabolism, the impaired antioxidant defense system and membrane pathology in schizophrenia, their interrelationships with the characteristic clinical symptoms and the implications for antipsychotic treatments. In schizophrenia, there is accumulating evidence of altered antioxidant enzyme activities and increased levels of lipid peroxidation, as well as altered levels of plasma antioxidants. Moreover, free radical-mediated abnormalities may contribute to specific aspects of schizophrenic symptomatology and complications of its treatment with antipsychotic drugs, as well as the development of tardive dyskinesia (TD). Finally, the potential therapeutic strategies implicated by the accumulating data on oxidative stress mechanisms for the treatment of schizophrenia are discussed.© 2013 Elsevier Inc.


Corrales-Medina V.F.,Ottawa Hospital Research Institute | Corrales-Medina V.F.,University of Ottawa | Musher D.M.,Baylor College of Medicine | Musher D.M.,Michael bakey Va Medical Center | And 6 more authors.
Circulation | Year: 2012

Background-Community-acquired pneumonia (CAP) affects > 5 million adults each year in the United States. Although incident cardiac complications occur in patients with community-acquired pneumonia, their incidence, timing, risk factors, and associations with short-term mortality are not well understood. Methods and Results-A total of 1343 inpatients and 944 outpatients with community-acquired pneumonia were followed up prospectively for 30 days after presentation. Incident cardiac complications (new or worsening heart failure, new or worsening arrhythmias, or myocardial infarction) were diagnosed in 358 inpatients (26.7%) and 20 outpatients (2.1%). Although most events (89.1% in inpatients, 75% in outpatients) were diagnosed within the first week, more than half of them were recognized in the first 24 hours. Factors associated with their diagnosis included older age (odds ratio [OR]=1.03; 95% confidence interval [CI], 1.02-1.04), nursing home residence (OR, 1.8; 95% CI, 1.2-2.9), history of heart failure (OR, 4.3; 95% CI, 3.0-6.3), prior cardiac arrhythmias (OR, 1.8; 95% CI, 1.2-2.7), previously diagnosed coronary artery disease (OR, 1.5; 95% CI, 1.04-2.0), arterial hypertension (OR, 1.5; 95% CI, 1.1-2.1), respiratory rate ≥ 30 breaths per minute (OR, 1.6; 95% CI, 1.1-2.3), blood pH < 7.35 (OR, 3.2; 95% CI, 1.8-5.7), blood urea nitrogen ≥ 30 mg/dL (OR, 1.5; 95% CI, 1.1-2.2), serum sodium < 130 mmol/L (OR, 1.8; 95% CI, 1.02-3.1), hematocrit ≥ 30% (OR, 2.0; 95% CI, 1.3-3.2), pleural effusion on presenting chest x-ray (OR, 1.6; 95% CI, 1.1-2.4), and inpatient care (OR, 4.8; 95% CI, 2.8-8.3). Incident cardiac complications were associated with increased risk of death at 30 days after adjustment for baseline Pneumonia Severity Index score (OR, 1.6; 95% CI, 1.04-2.5). Conclusions-Incident cardiac complications are common in patients with community-acquired pneumonia and are associated with increased short-term mortality. Older age, nursing home residence, preexisting cardiovascular disease, and pneumonia severity are associated with their occurrence. Further studies are required to test risk stratification and prevention and treatment strategies for cardiac complications in this population. Copyright © s 2012 American Heart Association. All rights reserved.


Daniels S.K.,University of Houston | Daniels S.K.,Michael bakey Va Medical Center | Anderson J.A.,Michael bakey Va Medical Center | Anderson J.A.,Baylor College of Medicine | And 2 more authors.
Stroke | Year: 2012

BACKGROUND AND PURPOSE-: Screening for dysphagia is essential to the implementation of preventive therapies for patients with stroke. A systematic review was undertaken to determine the evidence-based validity of dysphagia screening items using instrumental evaluation as the reference standard. METHODS-: Four databases from 1985 through March 2011 were searched using the terms cerebrovascular disease, stroke deglutition disorders, and dysphagia. Eligibility criteria were: homogeneous stroke population, comparison to instrumental examination, clinical examination without equipment, outcome measures of dysphagia or aspiration, and validity of screening items reported or able to be calculated. Articles meeting inclusion criteria were evaluated for methodological rigor. Sensitivity, specificity, and predictive capabilities were calculated for each item. RESULTS-: Total source documents numbered 832; 86 were reviewed in full and 16 met inclusion criteria. Study quality was variable. Testing swallowing, generally with water, was the most commonly administered item across studies. Both swallowing and nonswallowing items were identified as predictive of aspiration. Neither swallowing protocols nor validity were consistent across studies. CONCLUSIONS-: Numerous behaviors were found to be associated with aspiration. The best combination of nonswallowing and swallowing items as well as the best swallowing protocol remains unclear. Findings of this review will assist in development of valid clinical screening instruments. © 2012 American Heart Association, Inc.


Price R.B.,University of Pittsburgh | Mathew S.J.,Michael bakey Va Medical Center | Mathew S.J.,Baylor College of Medicine
CNS Drugs | Year: 2015

Ketamine, a widely used anesthetic agent, is currently being investigated as a novel therapeutic for depression and suicidality. Ketamine has garnered substantial attention from researchers, clinicians, media outlets, and patients alike, but numerous questions remain. One of the compelling features of ketamine is the rapidity of its antidepressant effects, which peak just 24 h after infusion, setting it apart from other existing treatments. Ketamine's rapid time course has inspired research efforts to explore its potential as a life-saving therapy for patients at imminent risk of suicide. In this article, we review current evidence supporting the rapid effects of ketamine on suicidal ideation in the context of unipolar and bipolar depression. We then discuss several future directions that are necessary before ketamine can be considered a viable treatment option for suicidality in clinical settings. These include: testing for a specific anti-suicidal effect - separate from overall antidepressant effects - to ascertain whether ketamine might hold promise for a broader class of suicidal patients; ensuring that acute benefits of ketamine can be prolonged over a clinically meaningful timeframe; and developing a better understanding of the mechanisms by which ketamine might reduce suicide risk. Such efforts will enable the field to more accurately assess the potential of ketamine, as well as its limitations, allowing for appropriate placement within the context of comprehensive clinical care for suicide prevention. © 2015 Springer International Publishing Switzerland.


Kar B.,Baylor College of Medicine | Kar B.,Michael bakey Va Medical Center | Gregoric I.D.,Baylor College of Medicine | Basra S.S.,Baylor College of Medicine | And 2 more authors.
Journal of the American College of Cardiology | Year: 2011

Objectives We evaluated the efficacy and safety of the percutaneous ventricular assist device (pVAD) in patients in severe refractory cardiogenic shock (SRCS) despite intra-aortic balloon pump (IABP) and/or high-dose vasopressor support. Background SRCS is associated with substantial mortality despite IABP counterpulsation. Until recently, there was no rapid, minimally invasive means of providing increased hemodynamic support in SRCS. Methods A total of 117 patients with SRCS implanted with TandemHeart pVAD (CardiacAssist, Inc., Pittsburgh, Pennsylvania) were studied, of whom 56 patients (47.9%) underwent active cardiopulmonary resuscitation immediately before or at the time of implantation. Data was collected regarding clinical characteristics, hemodynamics, and laboratory values. Results Eighty patients had ischemic and 37 patients had nonischemic cardiomyopathy. The average duration of support was 5.8 ± 4.75 days. After implantation, the cardiac index improved from median 0.52 (interquartile range [IQR]: 0.8) l/(min·m2) to 3.0 (IQR: 0.9) l/(min·m2) (p < 0.001). The systolic blood pressure and mixed venous oxygen saturation increased from 75 (IQR: 15) mm Hg to 100 (IQR: 15) mm Hg (p < 0.001) and 49 (IQR: 11.5) to 69.3 (IQR: 10) (p < 0.001), respectively. The urine output increased from 70.7 (IQR: 70) ml/day to 1,200 (IQR: 1,620) ml/day (p < 0.001). The pulmonary capillary wedge pressure, lactic acid level, and creatinine level decreased, respectively, from 31.53 ± 10.2 mm Hg to 17.29 ± 10.82 mm Hg (p < 0.001), 24.5 (IQR: 74.25) mg/dl to 11 (IQR: 92) mg/dl (p < 0.001), and 1.5 (IQR: 0.95) mg/dl to 1.2 (IQR: 0.9) mg/dl (p = 0.009). The mortality rates at 30 days and 6 months were 40.2% and 45.3%, respectively. Conclusions The pVAD rapidly reversed the terminal hemodynamic compromise seen in patients with SRCS refractory to IABP and vasopressor support. © 2011 American College of Cardiology Foundation.


Nguyen D.M.,Baylor College of Medicine | Nguyen D.M.,Michael bakey Va Medical Center | El-Serag H.B.,Baylor College of Medicine | El-Serag H.B.,Michael bakey Va Medical Center
Gastroenterology Clinics of North America | Year: 2010

Obesity has received considerable attention as a major health hazard because of the increase in the prevalence of obesity not only in the United States but also in several other countries worldwide. Obesity is caused by an interaction of environmental factors, genetic predisposition, and human behavior, and is associated with an increased risk of numerous chronic diseases, from diabetes and cancers to many digestive diseases. The obesity epidemic exerts a heavy toll on the economy with its massive health care costs. This article describes some of the epidemiologic features of obesity, including global prevalence, secular trends, risk factors, and burden of illness related to obesity with special emphasis on obesity trends in the United States.


Shorter D.,Michael bakey Va Medical Center | Domingo C.B.,Michael bakey Va Medical Center | Kosten T.R.,Baylor College of Medicine
Expert Opinion on Emerging Drugs | Year: 2015

Introduction: Cocaine use is a global public health concern of significant magnitude, negatively impacting both the individual as well as larger society. Despite numerous trials, the discovery of an effective medication for treatment of cocaine use disorder remains elusive.Areas covered: This article reviews the emerging pharmacotherapies for treatment of cocaine use disorder, focusing on those medications that are currently in Phase II or III human clinical trials. Articles reviewed were obtained through searches of PubMed, Ovid MEDLINE, Clinicaltrials.gov and the Pharmaprojects database.Expert opinion: Research into cocaine pharmacotherapy must continue to show innovation. Given that medications targeting single neurotransmitter systems have demonstrated little efficacy in treatment of cocaine use disorder, the recent focus on pharmacotherapeutic agents with multiple neurobiochemical targets represents an exciting shift in trial design and approach. Additionally, consideration of pharmacogenetics may be helpful in identification of subpopulations of cocaine-dependent individuals who may preferentially respond to medications. © 2014 Informa UK, Ltd.

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