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Wegener S, Artmann J, Luft AR, Buxton RB, Weller M, Wong EC. The time of maximum post-ischemic hyperperfusion indicates infarct growth following transient experimental ischemia. PLoS One 2013; 8:e65322. [PMID: 23741488 PMCID: PMC3669346 DOI: 10.1371/journal.pone.0065322] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Accepted: 04/25/2013] [Indexed: 11/30/2022] Open
Abstract
After recanalization, cerebral blood flow (CBF) can increase above baseline in cerebral ischemia. However, the significance of post-ischemic hyperperfusion for tissue recovery remains unclear. To analyze the course of post-ischemic hyperperfusion and its impact on vascular function, we used magnetic resonance imaging (MRI) with pulsed arterial spin labeling (pASL) and measured CBF quantitatively during and after a 60 minute transient middle cerebral artery occlusion (MCAO) in adult rats. We added a 5% CO2 - challenge to analyze vasoreactivity in the same animals. Results from MRI were compared to histological correlates of angiogenesis. We found that CBF in the ischemic area recovered within one day and reached values significantly above contralateral thereafter. The extent of hyperperfusion changed over time, which was related to final infarct size: early (day 1) maximal hyperperfusion was associated with smaller lesions, whereas a later (day 4) maximum indicated large lesions. Furthermore, after initial vasoparalysis within the ischemic area, vasoreactivity on day 14 was above baseline in a fraction of animals, along with a higher density of blood vessels in the ischemic border zone. These data provide further evidence that late post-ischemic hyperperfusion is a sequel of ischemic damage in regions that are likely to undergo infarction. However, it is transient and its resolution coincides with re-gaining of vascular structure and function.
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Baker SE, Wong EC, Wheatley CM, Foxx-Lupo WT, Martinez MG, Morgan MA, Sprissler R, Morgan WJ, Snyder EM. Genetic variation of SCNN1A influences lung diffusing capacity in cystic fibrosis. Med Sci Sports Exerc 2013; 44:2315-21. [PMID: 22776878 DOI: 10.1249/mss.0b013e318266ebc3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Epithelial Na channels (ENaCs) play a crucial role in ion and fluid regulation in the lung. In cystic fibrosis (CF), Na hyperabsorption results from ENaC overactivity, leading to airway dehydration. Previous work has demonstrated functional genetic variation of SCNN1A (the gene encoding the ENaC α-subunit), manifesting as an alanine (A) to threonine (T) substitution at amino acid 663, with the αT663 variant resulting in a more active channel. METHODS We assessed the influence of genetic variation of SCNN1A on the diffusing capacity of the lungs for carbon monoxide (DLCO) and nitric oxide (DLNO), together with alveolar-capillary membrane conductance (DM), pulmonary capillary blood volume, and alveolar volume (VA) at rest and during peak exercise in 18 patients with CF (10 homozygous for αA663 (AA group) and 8 with at least one T663 allele (AT/TT group)). Because of the more active channel, we hypothesized that the AT/TT group would show a greater increase in DLCO, DLNO, and DM with exercise because of exercise-mediated ENaC inhibition and subsequent attenuation of Na hyperabsorption. RESULTS The AT/TT group had significantly lower pulmonary function, weight, and body mass index than the AA group. Both groups had similar peak workloads, relative peak oxygen consumptions, and cardiopulmonary responses to exercise. The AT/TT group demonstrated a greater increase in DLNO, DLNO/VA, and DM in response to exercise (% increases: DLNO = 18 ± 11 vs 41 ± 38; DLNO/VA = 14 ± 21 vs 40 ± 37; DM = 15 ± 11 vs 41 ± 38, AA vs AT/TT, respectively). There were no differences between groups in absolute diffusing capacity measures at peak exercise. CONCLUSION These results suggest that genetic variation of the α-subunit of ENaC differentially affects the diffusing capacity response to exercise in patients with CF.
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Bhalla V, Zhao B, Azar KMJ, Wang EJ, Choi S, Wong EC, Fortmann SP, Palaniappan LP. Racial/ethnic differences in the prevalence of proteinuric and nonproteinuric diabetic kidney disease. Diabetes Care 2013; 36:1215-21. [PMID: 23238659 PMCID: PMC3631839 DOI: 10.2337/dc12-0951] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To examine racial/ethnic differences in the prevalence of diabetic kidney disease (DKD), with and without proteinuria, in an outpatient health care organization. RESEARCH DESIGN AND METHODS We examined electronic health records for 15,683 persons of non-Hispanic white (NHW), Asian (Asian Indian, Chinese, and Filipino), Hispanic, and non-Hispanic black (NHB) race/ethnicity with type 2 diabetes and no prior history of kidney disease from 2008 to 2010. We directly standardized age- and sex-adjusted prevalence rates of proteinuric DKD (proteinuria with or without low estimated glomerular filtration rate [eGFR]) or nonproteinuric DKD (low eGFR alone). We calculated sex-specific odds ratios of DKD in racial/ethnic minorities (relative to NHWs) after adjustment for traditional DKD risk factors. RESULTS Racial/ethnic minorities had higher rates of proteinuric DKD than NHWs (24.8-37.9 vs. 24.8%) and lower rates of nonproteinuric DKD (6.3-9.8 vs. 11.7%). On adjusted analyses, Chinese (odds ratio 1.39 for women and 1.56 for men), Filipinos (1.57 for women and 1.85 for men), Hispanics (1.46 for women and 1.34 for men), and NHBs (1.50 for women) exhibited significantly (P < 0.01) higher odds of proteinuric DKD than NHWs. Conversely, Chinese, Hispanic, and NHB women and Hispanic men had significantly lower odds of nonproteinuric DKD than NHWs. CONCLUSIONS We found novel racial/ethnic differences in DKD among patients with type 2 diabetes. Racial/ethnic minorities were more likely to have proteinuric DKD and less likely to have nonproteinuric DKD. Future research should examine diverse DKD-related outcomes by race/ethnicity to inform targeted prevention and treatment efforts and to explore the etiology of these differences.
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Simon AB, Griffeth VEM, Wong EC, Buxton RB. A novel method of combining blood oxygenation and blood flow sensitive magnetic resonance imaging techniques to measure the cerebral blood flow and oxygen metabolism responses to an unknown neural stimulus. PLoS One 2013; 8:e54816. [PMID: 23382977 PMCID: PMC3561406 DOI: 10.1371/journal.pone.0054816] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 12/17/2012] [Indexed: 11/24/2022] Open
Abstract
Simultaneous implementation of magnetic resonance imaging methods for Arterial Spin Labeling (ASL) and Blood Oxygenation Level Dependent (BOLD) imaging makes it possible to quantitatively measure the changes in cerebral blood flow (CBF) and cerebral oxygen metabolism (CMRO2) that occur in response to neural stimuli. To date, however, the range of neural stimuli amenable to quantitative analysis is limited to those that may be presented in a simple block or event related design such that measurements may be repeated and averaged to improve precision. Here we examined the feasibility of using the relationship between cerebral blood flow and the BOLD signal to improve dynamic estimates of blood flow fluctuations as well as to estimate metabolic-hemodynamic coupling under conditions where a stimulus pattern is unknown. We found that by combining the information contained in simultaneously acquired BOLD and ASL signals through a method we term BOLD Constrained Perfusion (BCP) estimation, we could significantly improve the precision of our estimates of the hemodynamic response to a visual stimulus and, under the conditions of a calibrated BOLD experiment, accurately determine the ratio of the oxygen metabolic response to the hemodynamic response. Importantly we were able to accomplish this without utilizing a priori knowledge of the temporal nature of the neural stimulus, suggesting that BOLD Constrained Perfusion estimation may make it feasible to quantitatively study the cerebral metabolic and hemodynamic responses to more natural stimuli that cannot be easily repeated or averaged.
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Holland AT, Zhao B, Wong EC, Choi SE, Wong ND, Palaniappan LP. Racial/ethnic differences in control of cardiovascular risk factors among type 2 diabetes patients in an insured, ambulatory care population. J Diabetes Complications 2013; 27:34-40. [PMID: 23062328 PMCID: PMC3587775 DOI: 10.1016/j.jdiacomp.2012.08.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 07/20/2012] [Accepted: 08/17/2012] [Indexed: 01/15/2023]
Abstract
AIMS This paper examines differences in cardiovascular disease risk factor control among racial/ethnic minorities (Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese, Hispanic/Latino, Black/African Americans) with type 2 diabetes compared to Non-Hispanic Whites with type 2 diabetes in an insured, outpatient setting. METHODS A three-year, cross-sectional sample of 15,826 patients with type 2 diabetes was studied between 2008 and 2010. Goal attainment rates for three cardiovascular disease risk factors (HbA1c, BP, LDL) were estimated. Logistic regression was used to determine the association between patient characteristics and control of risk factors. RESULTS Only one fifth (21.1%) of patients achieved simultaneous goal attainment (HbA1c, BP, LDL). After adjustment for patient characteristics and treatment, Black/African American women and men, and Filipino and Hispanic/Latino men were significantly less likely to simultaneously achieve all three goals, compared to Non-Hispanic Whites. Of the three goals, patients were more likely to achieve HbA1c goals (68.7%) than BP (45.7%) or LDL (58.5%) goals. Racial/ethnic differences were more apparent in risk factors that were under better control (i.e. HbA1c). CONCLUSIONS Cardiovascular risk factor control in type 2 diabetes is suboptimal, even in an insured population. Special attention may be required for specific racial/ethnic/gender groups.
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Bockman MD, Kansagra AP, Shadden SC, Wong EC, Marsden AL. Fluid Mechanics of Mixing in the Vertebrobasilar System: Comparison of Simulation and MRI. Cardiovasc Eng Technol 2012. [DOI: 10.1007/s13239-012-0112-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Guo J, Wong EC. Venous oxygenation mapping using velocity-selective excitation and arterial nulling. Magn Reson Med 2012; 68:1458-71. [PMID: 22294414 PMCID: PMC3342455 DOI: 10.1002/mrm.24145] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 12/06/2011] [Accepted: 12/12/2011] [Indexed: 11/10/2022]
Abstract
A new MRI technique to map the oxygenation of venous blood is presented. The method uses velocity-selective excitation and arterial nulling pulses, combined with phase sensitive signal detection to isolate the venous blood signal. T₂ of this signal along with a T₂-Y calibration curve yields estimates of venous oxygenation in situ. Results from phantoms and healthy human subjects under normoxic and hypoxic conditions are shown, and venous saturation levels estimated from both sagittal sinus and gray matter-based regions of interest are compared with the related techniques TRUST and QUIXOTIC. In addition, combined with an additional scan without arterial nulling pulses, the oxygen saturation level on arterial side can also be estimated.
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Goyal D, Wang EJ, Shen J, Wong EC, Palaniappan LP. Clinically identified postpartum depression in Asian American mothers. J Obstet Gynecol Neonatal Nurs 2012; 41:408-16. [PMID: 22536783 DOI: 10.1111/j.1552-6909.2012.01352.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVE To identify the clinical diagnosis rate of postpartum depression (PPD) in Asian American subgroups (Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese) compared to non-Hispanic Whites. DESIGN Cross-sectional study using electronic health records (EHR). SETTING A large, outpatient, multiservice clinic in Northern California. PARTICIPANTS A diverse clinical population of non-Hispanic White (N = 4582), Asian Indian (N = 1264), Chinese (N = 1160), Filipino (N = 347), Japanese (N = 124), Korean (N = 183), and Vietnamese (N = 147) mothers. METHODS Cases of PPD were identified from EHRs using physician diagnosis codes, medication usage, and age standardized for comparison. The relationship between PPD and other demographic variables (race/ethnicity, maternal age, delivery type, marital status, and infant gender) were examined in a multivariate logistic regression model. RESULTS The PPD diagnosis rate for all Asian American mothers in aggregate was significantly lower than the diagnosis rate in non-Hispanic White mothers. Moreover, of the six Asian American subgroups, PPD diagnosis rates for Asian Indian, Chinese, and Filipino mothers were significantly lower than non-Hispanic White mothers. In multivariate analyses, race/ethnicity, age, and cesarean were significant predictors of PPD. CONCLUSION In this insured population, PPD diagnosis rates were lower among Asian Americans, with variability in rates across the individual Asian American subgroups. It is unclear whether these lower rates are due to underreporting, underdiagnosis, or underutilization of mental health care in this setting.
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Zun Z, Varadarajan P, Pai RG, Wong EC, Nayak KS. Arterial spin labeled CMR detects clinically relevant increase in myocardial blood flow with vasodilation. JACC Cardiovasc Imaging 2012; 4:1253-61. [PMID: 22172781 DOI: 10.1016/j.jcmg.2011.06.023] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 06/29/2011] [Accepted: 06/30/2011] [Indexed: 11/20/2022]
Abstract
OBJECTIVES This study sought to determine whether arterial spin labeled (ASL) cardiac magnetic resonance (CMR) is capable of detecting clinically relevant increases in regional myocardial blood flow (MBF) with vasodilator stress testing in human myocardium. BACKGROUND Measurements of regional myocardial perfusion at rest and during vasodilatation are used to determine perfusion reserve, which indicates the presence and distribution of myocardial ischemia. ASL CMR is a perfusion imaging technique that does not require any contrast agents, and is therefore safe for use in patients with end-stage renal disease, and capable of repeated or continuous measurement. METHODS Myocardial ASL scans at rest and during adenosine infusion were incorporated into a routine CMR adenosine induced vasodilator stress protocol and was performed in 29 patients. Patients who were suspected of having ischemic heart disease based on first-pass imaging also underwent x-ray angiography. Myocardial ASL was performed using double-gated flow-sensitive alternating inversion recovery tagging and balanced steady-state free precession imaging at 3-T. RESULTS Sixteen patients were found to be normal and 13 patients were found to have visible perfusion defect based on first-pass CMR using intravenous gadolinium chelate. In the normal subjects, there was a statistically significant difference between MBF measured by ASL during adenosine infusion (3.67 ± 1.36 ml/g/min), compared to at rest (0.97 ± 0.64 ml/g/min), with p < 0.0001. There was also a statistically significant difference in perfusion reserve (MBF(stress)/MBF(rest)) between normal myocardial segments (3.18 ± 1.54) and the most ischemic segments in the patients with coronary artery disease identified by x-ray angiography (1.44 ± 0.97), with p = 0.0011. CONCLUSIONS This study indicates that myocardial ASL is capable of detecting clinically relevant increases in MBF with vasodilatation and has the potential to identify myocardial ischemia.
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Wong EC. Local head gradient coils: window(s) of opportunity. Neuroimage 2012; 62:660-4. [PMID: 22245342 DOI: 10.1016/j.neuroimage.2012.01.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 11/02/2011] [Accepted: 01/01/2012] [Indexed: 10/14/2022] Open
Abstract
At the Medical College of Wisconsin (MCW), prior to the 1991 announcement of the discovery of BOLD fMRI, all of the technical pieces that were needed for efficient BOLD fMRI imaging were assembled for other applications, allowing MCW to jump into the fMRI business just days after the announcement. Central among these pieces was single shot EPI, implemented at MCW using a three axis local head gradient coil. This article describes the development of local gradient coil technology at MCW, and a historical perspective on local head gradient coils in general.
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Shin DD, Liu TT, Wong EC, Shankaranarayanan A, Jung Y. Pseudocontinuous arterial spin labeling with optimized tagging efficiency. Magn Reson Med 2012; 68:1135-44. [PMID: 22234782 DOI: 10.1002/mrm.24113] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 11/01/2011] [Accepted: 11/18/2011] [Indexed: 11/10/2022]
Abstract
The adiabatic inversion of blood in pseudocontinuous arterial spin labeling (PCASL) is highly sensitive to off-resonance effects and gradient imperfections and this sensitivity can lead to tagging efficiency loss and unpredictable variations in cerebral blood flow estimates. This efficiency loss is caused by a phase tracking error between the RF pulses and the flowing spins. This article introduces a new method, referred to as Optimized PCASL (OptPCASL), that minimizes the phase tracking error by applying an additional compensation RF phase term and in-plane gradients to the PCASL pulse train. The optimal RF phase and gradient amplitudes are determined using a prescan procedure, which consists of a series of short scans interleaved with automated postprocessing routines integrated to the scanner console. The prescan procedure is shown to minimize the phase tracking error in a robust and time efficient manner. As an example of its application, the use of OptPCASL for the improved detection of functional activation in the visual cortex is demonstrated and temporal signal-to-noise ratio (SNR), image SNR, and baseline cerebral blood flow measures are compared to those acquired from conventional PCASL.
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Zun Z, Varadarajan P, Pai RG, Wong EC, Nayak KS. Arterial spin labeled MRI detects clinically relevant increases in myocardial blood flow with vasodilatation. J Cardiovasc Magn Reson 2011. [PMCID: PMC3106923 DOI: 10.1186/1532-429x-13-s1-o94] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Zun Z, Jao T, Smith N, Varadarajan P, Pai RG, Wong EC, Nayak KS. Myocardial ASL perfusion reserve test detects ischemic segments in initial cohort of 10 patients with angiographic CAD. J Cardiovasc Magn Reson 2011. [PMCID: PMC3106566 DOI: 10.1186/1532-429x-13-s1-p110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Azar KMJ, Moreno MR, Wong EC, Shin JJ, Soto C, Palaniappan LP. Accuracy of data entry of patient race/ethnicity/ancestry and preferred spoken language in an ambulatory care setting. Health Serv Res 2011; 47:228-40. [PMID: 22092342 DOI: 10.1111/j.1475-6773.2011.01305.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2011] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE To describe data collection methods and to audit staff data entry of patient self-reported race/ethnicity/ancestry and preferred spoken language (R/E/A/L) information. DATA SOURCE/STUDY SETTING Large mixed payer outpatient health care organization in Northern California, June 2009. STUDY DESIGN Secondary analysis of an audit planned and executed by the Department of Clinical Services. DATA COLLECTION/EXTRACTION METHODS We analyzed concordance between patient written responses and staff data entry. PRINCIPAL FINDINGS The data entry accuracy rate across questions was high, ranging from 92 to 97 percent. Inaccuracies were due to human error (62 percent), flaws in system design (2 percent), or some combination of both (35 percent). CONCLUSIONS This study highlights the high accuracy of patient self-reported R/E/A/L data entry and identifies some areas for improvement in staff training and technical system design to facilitate further progress.
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Buračas GT, Jung Y, Lee J, Buxton RB, Wong EC, Liu TT. On multiple alternating steady states induced by periodic spin phase perturbation waveforms. Magn Reson Med 2011; 67:1412-8. [PMID: 21826730 DOI: 10.1002/mrm.23105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 05/29/2011] [Accepted: 06/25/2011] [Indexed: 11/09/2022]
Abstract
Direct measurement of neural currents by means of MRI can potentially open a high temporal resolution (10-100 ms) window applicable for monitoring dynamics of neuronal activity without loss of the high spatial resolution afforded by MRI. Previously, we have shown that the alternating balanced steady state imaging affords high sensitivity to weak periodic currents owing to its amplification of periodic spin phase perturbations. This technique, however, requires precise synchronization of such perturbations to the radiofrequency pulses. Herein, we extend alternating balanced steady state imaging to multiple balanced alternating steady states for estimation of neural current waveforms. Simulations and phantom experiments show that the off-resonance profile of the multiple alternating steady state signal carries information about the frequency content of driving waveforms. In addition, the method is less sensitive than alternating balanced steady state to precise waveform timing relative to radiofrequency pulses. Thus, multiple alternating steady state technique is potentially applicable to MR imaging of the waveforms of periodic neuronal activity.
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Snyder EM, Wong EC, Foxx-Lupo WT, Wheatley CM, Cassuto NA, Patanwala AE. Effects of an Inhaled β2-Agonist on Cardiovascular Function and Sympathetic Activity in Healthy Subjects. Pharmacotherapy 2011; 31:748-56. [DOI: 10.1592/phco.31.8.748] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Wang EJ, Wong EC, Dixit AA, Fortmann SP, Linde RB, Palaniappan LP. Type 2 diabetes: identifying high risk Asian American subgroups in a clinical population. Diabetes Res Clin Pract 2011; 93:248-254. [PMID: 21665315 PMCID: PMC3156287 DOI: 10.1016/j.diabres.2011.05.025] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 04/26/2011] [Accepted: 05/16/2011] [Indexed: 12/23/2022]
Abstract
AIMS We compared the prevalence and treatment of type 2 diabetes across Asian American subgroups (Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese) and Non-Hispanic Whites (NHWs) in a Northern California healthcare system. METHODS A three-year, cross-sectional sample of patient electronic health records was accessed to compare diabetes prevalence in 21,816 Asian and 73,728 NHWs aged 35+ years. Diabetes was classified through ICD-9 codes, abnormal laboratory values, or use of oral anti-diabetic medication. Multivariate adjusted prevalence rates for each Asian subgroup, and adjusted odds ratios (OR) relative to NHWs, were compared. RESULTS Age-adjusted prevalence ranged from 5.8% to 18.2% (women) and 8.1 to 25.3% (men). Age-adjusted ORs of Asian subgroups ranged 1.11-3.94 (women) and 1.14-4.56 (men). The odds of diabetes were significantly higher in Asian Indians (women OR 3.44, men OR 3.54) and Filipinos (women OR 3.94, men OR 4.56), compared to NHWs. Results for Asian Indians and Filipinos were similar with age-and-BMI adjustment. Treatment rates across subgroups were 59.7-82.0% (women) and 62.9-79.4% (men). CONCLUSIONS Heterogeneity exists in the prevalence of diabetes across Asian subgroups, independent of obesity prevalence. Asian Indian and Filipino subgroups had particularly high prevalence of diabetes when compared to NHWs. Future studies should explore these clinically important differences among Asian subgroups.
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Palaniappan LP, Muzaffar AL, Wang EJ, Wong EC, Orchard TJ. Shared medical appointments: promoting weight loss in a clinical setting. J Am Board Fam Med 2011; 24:326-8. [PMID: 21551406 PMCID: PMC3217311 DOI: 10.3122/jabfm.2011.03.100220] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
INTRODUCTION Shared medical appointments (SMAs) are 90-minute group appointments for patients with similar medical complaints. SMAs include components of a traditional office visit but provide further emphasis on health education. The effectiveness of SMAs on weight-loss in an outpatient setting has not been studied. METHODS Weight-loss SMAs were offered by one physician at the Palo Alto Medical Foundation. Teaching content included Diabetes Prevention Program materials. This analysis includes patients who attended at least one SMA (n = 74) compared with patients in the same physician's practice who had at least one office visit and a body mass index ≥ 25 kg/m(2) (n = 356). RESULTS The SMA group had a higher proportion of women than the comparison group (76% vs 64%) and were older (mean, 52.4 years; SD, 13.1 years vs mean, 47.0 years; SD, 13.3 years). SMA patients on average lost 1.0% of their baseline weight. Patients in the comparison group on average gained 0.8% of their baseline weight. DISCUSSION SMAs may be a viable option for physicians to promote weight loss in the clinical setting.
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Baker SE, Wheatley CM, Cassuto NA, Wong EC, Foxx‐Lupo WT, Snyder EM. Genetic Variation of the Alpha Subunit of ENaC Influences Lung Diffusion during Peak Exercise. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.862.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Palaniappan LP, Wong EC, Shin JJ, Fortmann SP, Lauderdale DS. Asian Americans have greater prevalence of metabolic syndrome despite lower body mass index. Int J Obes (Lond) 2011; 35:393-400. [PMID: 20680014 PMCID: PMC2989340 DOI: 10.1038/ijo.2010.152] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To examine the relationship between body mass index (BMI) and metabolic syndrome for Asian Americans and non-Hispanic Whites (NHWs), given that existing evidence shows racial/ethnic heterogeneity exists in how BMI predicts metabolic syndrome. RESEARCH DESIGN AND METHODS Electronic health records of 43,507 primary care patients aged 35 years and older with self-identified race/ethnicity of interest (Asian Indian, Chinese, Filipino, Japanese, Korean, Vietnamese or NHW) were analyzed in a mixed-payer, outpatient-focused health-care organization in the San Francisco Bay Area. RESULTS Metabolic syndrome prevalence is significantly higher in Asians compared with NHWs for every BMI category. For women at the mean age of 55 and BMI of 25 kg m(-2), the predicted prevalence of metabolic syndrome is 12% for NHW women compared with 30% for Asians; similarly for men, the predicted prevalence of metabolic syndrome is 22% for NHWs compared with 43% of Asians. Compared with NHW women and men with a BMI of 25 kg m(-2), comparable prevalence of metabolic syndrome was observed at BMI of 19.6 kg m(-2) for Asian women and 19.9 kg m(-2) for Asian men. A similar pattern was observed in disaggregated Asian subgroups. CONCLUSIONS In spite of the lower BMI values and lower prevalence of overweight/obesity than NHWs, Asian Americans have higher rates of metabolic syndrome over the range of BMI. Our results indicate that BMI ranges for defining overweight/obesity in Asian populations should be lower than for NHWs.
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Jung Y, Wong EC, Liu TT. Multiphase pseudocontinuous arterial spin labeling (MP-PCASL) for robust quantification of cerebral blood flow. Magn Reson Med 2011; 64:799-810. [PMID: 20578056 DOI: 10.1002/mrm.22465] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Pseudocontinuous arterial spin labeling (PCASL) has been demonstrated to provide the sensitivity of the continuous arterial spin labeling method while overcoming many of the limitations of that method. Because the specification of the phases in the radiofrequency pulse train in PCASL defines the tag and control conditions of the flowing arterial blood, its tagging efficiency is sensitive to factors, such as off-resonance fields, that induce phase mismatches between the radiofrequency pulses and the flowing spins. As a result, the quantitative estimation of cerebral blood flow with PCASL can exhibit a significant amount of error when these factors are not taken into account. In this paper, the sources of the tagging efficiency loss are characterized and a novel PCASL method that utilizes multiple phase offsets is proposed to reduce the tagging efficiency loss in PCASL. Simulations are performed to evaluate the feasibility and the performance of the proposed method. Quantitative estimates of cerebral blood flow obtained with multiple phase offset PCASL are compared to estimates obtained with conventional PCASL and pulsed arterial spin labeling. Our results show that multiple phase offset PCASL provides robust cerebral blood flow quantification while retaining much of the sensitivity advantage of PCASL.
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Palaniappan LP, Maxwell AE, Crespi CM, Wong EC, Shin J, Wang EJ. Population Colorectal Cancer Screening Estimates: Comparing Self-Report to Electronic Health Record Data in California. INTERNATIONAL JOURNAL OF CANCER PREVENTION 2011; 4:28540. [PMID: 21857818 PMCID: PMC3157148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
INTRODUCTION: Population-based surveys are used to assess colorectal cancer (CRC) screening rates, but may be subject to self-report biases. Clinical data from electronic health records (EHR) are another data source for assessing screening rates and self-report bias; however, use of EHR data for population research is relatively new. We sought to compare CRC screening rates from a self-report survey, the 2007 California Health Interview Survey (CHIS), to EHR data from Palo Alto Medical Foundation (PAMF), a multi-specialty healthcare organization serving three counties in California. METHODS: Ever- and up-to-date CRC screening rates were compared between CHIS respondents (N=18,748) and PAMF patients (N=26,283). Both samples were limited to English proficient subjects aged 51-75 with health insurance and a physician visit in the past two years. PAMF rates were age-sex standardized to the CHIS population. Analyses were stratified by racial/ethnic group. RESULTS: EHR data included PAMF internally completed tests (84%), and patient-reported externally completed tests which were either confirmed (7%) or unconfirmed (9%) by a physician. When excluding unconfirmed tests, PAMF screening rates were 6-14 percentage points lower than CHIS rates, for both ever- and up-to-date CRC screening among Non-Hispanic White, Black, Hispanic/Latino, Chinese, Filipino and Japanese subjects. When including unconfirmed tests, differences in screening rates between the two data sets were minimal. CONCLUSION: Comparability of CRC screening rates from survey data and clinic-based EHR data depends on whether or not unconfirmed patient-reported tests in EHR are included. This indicates a need for validated methods of calculating CRC screening rates in EHR data.
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Wheatley CM, Foxx-Lupo WT, Cassuto NA, Wong EC, Daines CL, Morgan WJ, Snyder EM. Impaired lung diffusing capacity for nitric oxide and alveolar-capillary membrane conductance results in oxygen desaturation during exercise in patients with cystic fibrosis. J Cyst Fibros 2010; 10:45-53. [PMID: 21050829 DOI: 10.1016/j.jcf.2010.09.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 09/28/2010] [Accepted: 09/30/2010] [Indexed: 11/27/2022]
Abstract
BACKGROUND Exercise has been shown to be beneficial for patients with cystic fibrosis (CF), but for some CF patients there is a risk of desaturation, although the predicting factors are not conclusive or reliable. We sought to determine the relationship between the diffusion capacity of the lungs for nitric oxide and carbon monoxide (DLNO and DLCO) and the components of DLCO: alveolar-capillary membrane conductance (D(M)), and pulmonary capillary blood volume (V(C)) on peripheral oxygen saturation (SaO(2)) at rest and during exercise in CF. METHODS 17 mild/moderate CF patients and 17 healthy subjects were recruited (age=26±7 vs. 23±8 years, ht=169±8 vs. 166±8 cm, wt=65±9 vs. 59±8 kg, BMI=23±3 vs. 22±3 kg/m(2), VO(2PEAK)=101±36 vs. 55±25%pred., FEV(1)=92±22 vs. 68±25%pred., for healthy and CF, respectively, mean±SD, VO(2PEAK) and FEV(1) p<0.001). Subjects performed incremental cycle ergometry to exhaustion with continuous monitoring of SaO(2) and measures of DLNO, DLCO, D(M) and V(C) at each stage. RESULTS CF patients had a lower SaO(2) at rest and peak exercise (rest=98±1 vs. 96±1%, peak=97±2 vs. 93±5%, for healthy and CF, respectively, p<0.01). At rest, DLNO, DLCO, D(M) were significantly lower in the CF group (p<0.01). The difference between groups was augmented with exercise (DLNO=117±4 vs. 73±3ml/min/mmHg; DLCO=34±8 vs. 23±8ml/min/mmHg; D(M)=50±1 vs. 34±1, p<0.001, for healthy and CF respectively). Peak SaO(2) was related to resting DLNO in CF patients (r=0.65, p=0.003). CONCLUSIONS These results suggest a limitation in exercise-mediated increases in membrane conductance in CF which may contribute to a drop in SaO(2) and that resting DLNO can account for a large portion of the variability in SaO(2).
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Wong EC, Wheatley CM, Cassuto NA, Foxx‐Lupo WT, Patanwala AE, Snyder EM. Cardiovascular Effects of a Nebulized B‐agonist Compared to Saline in Healthy Humans. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.596.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Wheatley CM, Cassuto NA, Foxx‐Lupo WT, Wong EC, Delamere NA, Snyder EM. Relationship Between Exhaled Na+ and the Diffusion Capacity of the Lungs for Carbon Monoxide (DLCO) and Alveolar‐Capillary Membrane Conductance in Healthy Humans. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.1063.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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