Hong Lai

Johns Hopkins Medicine, Baltimore, Maryland, United States

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Publications (64)286.78 Total impact

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    ABSTRACT: Cardiac steatosis is a manifestation of ectopic fat deposition and is associated with obesity. The impact of chronic cocaine use on obesity measures and on the relationship between obesity measures and cardiac steatosis is not well-characterized. The objectives of this study were to compare obesity measures in chronic cocaine users and nonusers, and to explore which factors, in addition to obesity measures, are associated with myocardial triglyceride in African Americans, using noninvasive magnetic resonance spectroscopy.
    Journal of Addiction Medicine 10/2014; · 1.71 Impact Factor
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    ABSTRACT: Quantitative measurements of coronary plaque volume may play a role in serial studies to determine disease progression or regression. Our aim was to evaluate the interscan reproducibility of quantitative measurements of coronary plaque volumes using a standardized automated method.
    European Radiology 06/2014; 24(9). · 4.34 Impact Factor
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    ABSTRACT: Cardiac magnetic resonance (CMR) is a standard of reference for cardiac structure and function. Recent advances in T1 mapping and spectroscopy also provide assessment of myocardial tissue composition. However, the reference ranges of left ventricular parameters have rarely been assessed in an African-American (AA) population without known cardiac disease. To estimate the reference values of myocardial structure, function, and tissue composition by CMR and to explore their relationships to serologic factors and cardiovascular risk factors in asymptomatic AAs with low Framingham risk, between November 2010 and June 2012, 92 healthy AAs aged ≥21 years, from Baltimore, MD, were enrolled in an observational study. CMR examination was performed on a 3T scanner. Proton magnetic resonance spectroscopy was performed to noninvasively quantify myocardial triglyceride content. Native T1 values were obtained from modified Look-Locker inversion recovery sequence. The median age was 37 (interquartile range IQR 27 to 44) years (41% men). The median native T1 time of the myocardium was 1,228 ms (IQR 1,200 to 1,263) with no gender difference. The median myocardial fat content was 0.6% (IQR 0.7% to 4.6%). Native T1 time was not influenced by age, sex, and body mass index. Among the factors investigated, myocardial fat and elevated C-reactive protein (>2.0 mg/dL) were independently associated with T1 relaxation time. Native T1 time was also independently associated with left ventricular end-diastolic volume indexed to body surface area. In conclusion, this study of asymptomatic AAs provides reference ranges for cardiovascular structure, function, and tissue composition. Alterations in myocardial fat are associated with native T1 time, a CMR measure of interstitial fibrosis.
    The American Journal of Cardiology 06/2014; · 3.43 Impact Factor
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    ABSTRACT: This study evaluated the effect of intravenous (IV) catheter gauge size on catheter placement, contrast infusion, and image quality for patients undergoing IV contrast-enhanced multidetector computed tomography (MDCT). One thousand consecutive adult outpatients undergoing IV contrast-enhanced MDCT and 10 IV insertion CT nurses were observed from IV catheter selection through IV removal. Patients' demographics, number of sticks required, catheter gauge during each attempt, time for catheter placement, IV nurses' assessment of vein quality and contrast infusion parameters were recorded. Scan quality was assessed subjectively. Subjects included 547 men and 453 women, with a mean age 59.2 years (range, 19-92 years). Median number of catheter attempts was 1 per patient (range, 1-9). Catheters were successfully placed in 98%. First and final catheters were most commonly 20 gauge (59% and 56%, respectively), followed by 22 gauge (34% for both), 18 gauge (6% for both), and 24 gauge (2% and 3%, respectively). Mean infusion rate correlated with catheter gauge: 5.3 mL/s for 18 gauge; 3.5 mL/s for 20 gauge; 2.3 mL/s for 22 gauge; and 1.7 mL/s for 24 gauge (P < 0.0001). Target infusion rate of ≥ 3 mL/s was related to catheter gauge (100% of 18 gauge, 71% of 20 gauge, 11% of 22 gauge, and 0% of 24 gauge; P < 0.0001). Nine hundred sixty-eight subjects underwent imaging. Most of the CT examinations (935/968 [97%]) were of acceptable quality. Experienced IV starters usually achieve IV access in one attempt by tailoring IV catheter gauge to vein quality; however, target infusion rates are not likely to be achieved with 22- and 24-gauge catheters, used in nearly 1/3 of the patients in this study.
    Journal of computer assisted tomography 03/2014; · 1.38 Impact Factor
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    ABSTRACT: Background Treatment decisions for ascending aortic aneurysms are guided by measurements from CT angiograms. Objective To evaluate the reproducibility of these measurements using manual techniques and advanced imaging software. Methods Two radiologists measured maximal ascending aorta diameter on CT angiograms in 30 subjects at four separate reading sessions—two with manual techniques and two using semiautomated software analysis. Inter- and intraobserver variability was assessed using Bland-Altman plots and Spearman’s correlation coefficients. Results Interobserver variability was smaller for the software-assisted method. Limits of agreement for manual method were [-4.2 mm, 9.2 mm]; as compared to [-4.0 mm, 4.6 mm] for software-assisted; coefficients of repeatability were 6.8 mm and 4.3 mm. Intraobserver variability was inconsistent between readers. There was strong correlation between observers using both methods (R2 = 0.8078-0.9881, p<0.05 for all). Conclusion The use of an advanced imaging software for ascending aortic aneurysm measurement reduces interobserver variability.
    Journal of cardiovascular computed tomography 03/2014; · 2.55 Impact Factor
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    ABSTRACT: Cardiac steatosis is common in patients with diabetes or obesity, and cardiac steatosis may result in cardiomyopathy. However, factors associated with cardiac steatosis have not been reported in healthy individuals without diabetes and hypertension. The objectives of this study were to explore factors associated with myocardial triglyceride levels, and to examine the association between myocardial triglyceride and regional left ventricular (LV) function in healthy African Americans (AAs). Between November 2010 and June 2012, 92 healthy AAs aged 21years or older, without clinical evidence of cardiac dysfunction, coronary artery disease, diabetes, or hypertension from Baltimore, Maryland, were enrolled in an observational proton magnetic resonance spectroscopy and imaging study investigating factors associated with cardiac steatosis, and the relationships between cardiac steatosis and LV volumes and LV function. Among the participants, all had a low Framingham risk; 31 had a normal BMI, 23 were overweight and 38 were obese. The median myocardial triglyceride content was 0.5% (IQR: 0.3-1.0%). Among the factors investigated, BMI (R(2)=0.43, p=<0.0001) was independently associated with myocardial triglyceride. Overall, myocardial triglyceride was not associated with LV EF/structure, but may be associated with regional LV function. In healthy AA adults, obesity is associated with cardiac steatosis. In contrast to studies in patients with diabetes suggesting a link between cardiac steatosis and LV dysfunction, this study found no relationship between cardiac steatosis and left ventricular volumes or EF, though there is some evidence suggesting that cardiac steatosis may be associated with LV regional function in healthy AA women.
    International journal of cardiology 01/2014; · 6.18 Impact Factor
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    ABSTRACT: Chronic cocaine use may lead to premature atherosclerosis, but the prevalence of and risk factors for coronary artery disease (CAD) in asymptomatic cocaine users have not been reported. The objective of this study was to examine whether vitamin D deficiency is associated with the development of CAD in human immunodeficiency virus (HIV)-infected African American cocaine users with low CAD risk. In this prospective follow-up study, we investigated 169 HIV-infected African American cocaine users with low Framingham risk at baseline. The main outcome measures were incidence of subclinical CAD and development of subclinical CAD. Fifty of the 169 African Americans had evidence of subclinical disease on the initial cardiac computed tomography. A second cardiac computed tomography was performed on the 119 African Americans without disease on the first scan. The total sum of person-years of follow-up was 289.6. Subclinical CAD was detected in 11 of these, yielding an overall incidence of 3.80/100 person-years (95% confidence interval 1.90-6.80). Among the factors investigated, only vitamin D deficiency was independently associated with development of subclinical CAD. The study did not find significant associations between CD4 count, HIV viral load, or antiretroviral treatment use and the incidence of subclinical CAD. This study appears to suggest that there is a threshold level of vitamin D (10 ng/mL) above which the effect of vitamin D on subclinical CAD is diminished. The incidence of subclinical CAD in HIV-infected African American cocaine users with low CAD risk is high, especially in those with vitamin D deficiency. Well designed randomized clinical trials are warranted to confirm the role of vitamin D deficiency in the development of CAD in HIV-infected African American cocaine users with low CAD risk.
    Vascular Health and Risk Management 11/2013; 9:729-737.
    This article is viewable in ResearchGate's enriched format
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    ABSTRACT: To determine the prevalence of unsuspected thyroid nodules on contrast enhanced 16- and 64-modified discrete cosine transform (MDCT) of the chest, in a population of adult outpatients imaged for indications other than thyroid disease. This retrospective study involved review of intravascular contrast-enhanced MDCT scans of the chest from 3077 consecutive adult outpatients, to identify unsuspected thyroid nodules. Exclusion criteria included history of thyroid cancer, known thyroid nodules or thyroid disease and risk factors for thyroid cancer, as evidenced by their medical records. One of 9 radiologists recorded number of nodules, location and bidirectional measurement of largest nodule, as well as amount of thyroid visualized on the chest computed tomography (CT). Presence of nodule was correlated with age, gender, race and percentage of thyroid imaged. A total of 2510 (2510/3077 or 81.6%) study subjects were included in the data analysis; among them, one or more nodules were identified in 629 subjects (629/2510 or 25.1%), with 242 (242/629 or 38.5%) having multiple nodules. Patients with nodule(s) were significantly older than those without (64 ± 13 years vs 58 ± 14 years, P < 0.0001), and female gender was associated with presence of nodule(s) (373/1222 or 30.5% vs 256/1288 or 19.9%, P < 0.0001). Women were also more likely having multiple nodules (167/373 or 44.8%) compared to men (75/256 or 29.3%, P < 0.0001). The majority of nodules (427/629 or 67.9%) were less than 1 cm. This retrospective review revealed a prevalence of 25.1% for unsuspected thyroid nodules on contrast-enhanced chest CT.
    World journal of radiology. 07/2012; 4(7):311-7.
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    ABSTRACT: Premature coronary artery disease (CAD) is a major concern in human immunodeficiency virus (HIV)-infected African Americans. The objectives of the study were to estimate the incidence of subclinical CAD, defined by the presence of coronary plaque and/or calcification on cardiac computed tomography (CT), and to identify the associated risk factors in this vulnerable population. Between August 2003 and September 2010, 188 HIV-infected African Americans without known, or symptoms of, CAD underwent cardiac CT. The subset without demonstrable disease underwent a second cardiac CT approximately 2 years later. The incidence of disease over that period and the effects of antiretroviral treatment and other known and hypothesized risk factors were investigated. Sixty-nine of these 188 African Americans had evidence of subclinical disease on the initial cardiac CT, confirming prior high prevalence reports. A second cardiac CT was performed on 119 African Americans without disease approximately 2 years later. The total person-years of follow-up was 284.4. Subclinical CAD was detected in 14 of these, yielding an overall incidence of 4.92/100 person-years (95% confidence interval, 2.69-8.26). Among the factors investigated, only male sex and vitamin D deficiency were independently associated with the development of subclinical CAD. The study did not find significant associations between CD4 count, HIV viral load, antiretroviral treatment use, or cocaine use and the incidence of subclinical CAD. The incidence of subclinical CAD in African Americans with HIV infection is provocatively high. Larger studies are warranted to confirm the role of vitamin D deficiency in the development of CAD in HIV-infected African Americans.
    Journal of Investigative Medicine 04/2012; 60(5):801-7. · 1.50 Impact Factor
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    ABSTRACT: Growing evidence suggests that vitamin D deficiency Is associated with clinical coronary artery disease (CAD). The relationship between vitamin D deficiency and subclinical CAD in HIV-infected individuals is not well-characterized. Computed tomographic (CT) coronary angiography was performed using contrast-enhanced 64-slice multidetector CT imaging, and vitamin D levels and the presence of traditional and novel risk factor for CAD were obtained in 674 HIV-infected African American (AA) participants aged 25-54 years in Baltimore, MD, without symptoms/clinical evidence of CAD. The prevalence of vitamin D deficiency (25-hydroxy vitamin D <10 ng/mL) was 20.0% (95% confidence interval [CI], 16.9-23.1). Significant (≥50%) coronary stenosis was present in 64 (9.5%) of 674 participants. Multiple logistic regression analysis revealed that male gender (adjusted odds ratio [OR], 2.19; 95% CI, 1.17-4.10), diastolic BP ≥85 mmHg (adjusted OR: 1.94, 95% CI: 1.02 -3.68), low-density lipoprotein cholesterol ≥100 mg/dL (adjusted OR, 1.95; 95% CI, 1.13-3.36), cocaine use for ≥15 years (adjusted OR, 1.77; 95% CI, 1.01-3.10), use of antiretroviral therapies for ≥6 months (adjusted OR, 2.26; 95% CI, 1.17-4.36), year of enrollment after 2005 (adjusted ORs for 2006-2007, 2008-2009, and 2010 were 0.32 [95% CI, 0.13-0.76], 0.26 [95% CI, 0.12-0.56], and 0.32 (95% CI, 0.15-0.65], respectively), and vitamin D deficiency (adjusted OR, 2.28; 95% CI, 1.23-4.21) were independently associated with significant coronary stenosis. Both vitamin D deficiency and silent CAD are prevalent in HIV-infected AAs. In addition to management of traditional CAD risk factors and substance abuse, vitamin D deficiency should be evaluated in HIV-infected AAs. These data support the conduct of a prospective trial of vitamin D in this high-risk patient population.
    Clinical Infectious Diseases 03/2012; 54(12):1747-55. · 9.42 Impact Factor
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    ABSTRACT: Stroke remains a leading cause of death in the United States. While stroke-related mortality in the USA has declined over the past decades, stroke death rates are still higher for blacks than for whites, even at younger ages. The purpose of this study was to estimate the frequency of a lipid core and explore risk factors for its presence in asymptomatic, young-to-middle-aged urban African American adults recruited from inner-city Baltimore, Md., USA. Between August 28, 2003, and May 26, 2005, 198 African American participants aged 30-44 years from inner-city Baltimore, Md., were enrolled in an observational study of subclinical atherosclerosis related to HIV and cocaine use. In addition to clinical examinations and laboratory tests, B-mode ultrasound for intima-media thickness of the internal carotid arteries was performed. Among these 198, 52 were selected from the top 30th percentile of maximum carotid intima-media thickness by ultrasound, and high-resolution black blood MRI images were acquired through their carotid plaque before and after the intravenous administration of gadodiamide. Of these 52, 37 with maximum segmental thickness by MRI >1.0 mm were included in this study. Lumen and outer wall contours were defined using semiautomated analysis software. The frequency of a lipid core in carotid plaque was estimated and risk factors for lipid core presence were explored using logistic regression analysis. Of the 37 participants in this study, 12 (32.4%) were women. The mean age was 38.7 ± 4.9 years. A lipid core was present in 9 (17%) of the plaques. Seventy percent of the study participants had a history of cigarette smoking. The mean total cholesterol level was 176.1 ± 37.3 mg/dl, the mean systolic blood pressure was 113.1 ± 13.3 mm Hg, and the mean diastolic blood pressure was 78.9 ± 9.5 mm Hg. There were 5 participants with hypertension (13.5%). Twelve (32%) participants had a history of chronic cocaine use, and 23 (62%) were HIV positive. Among the factors investigated, including age, sex, blood pressure, cigarette smoking, C-reactive protein, fasting glucose, triglycerides, serum total cholesterol, coronary calcium, cocaine use, and HIV infection, only total cholesterol was significantly associated with the presence of a lipid core. This study revealed an unexpectedly high rate of the presence of lipid core in carotid plaque and highlights the importance of cholesterol lowering to prevent cerebrovascular disease in this population. Further population-based studies are warranted to confirm these results.
    Cerebrovascular Diseases 02/2012; 33(3):295-301. · 3.70 Impact Factor
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    ABSTRACT: BACKGROUND: Clinical and epidemiological evidence suggests that HIV infection and cocaine use are associated with an increased risk of premature atherosclerosis. The underlying mechanisms linking HIV infection and cocaine use with early atherosclerosis remain elusive. METHODS AND RESULTS: Endothelin-1 (ET-1) levels in 360 African American participants in Baltimore, Maryland were measured. Quantile regression analysis was performed to examine the associations between ET-1, HIV infection, cocaine use, and other relevant clinical factors. The median of ET-1 in plasma, (1.05pg/mL with interquartile range: 0.73, 1.40) for those with HIV infection was significantly higher than values for those without HIV infection (0.74pg/mL with interquartile range: 0.61, 0.93). The median of ET-1 was markedly higher in chronic cocaine users (0.96pg/mL with interquartile range: 0.71, 1.36) than that in non-cocaine users (0.72pg/mL with interquartile range: 0.58, 1.06). Multivariate quantile regression suggested that HIV infection and duration of cocaine use were independently associated with plasma ET-1 levels after controlling for potential confounding factors. CONCLUSIONS: This study may provide insight into the mechanism of premature atherosclerosis in HIV-infected cocaine users and suggest that measurement of ET-1 in plasma can be used as a marker of early atherosclerosis in HIV infected patients and cocaine users.
    International journal of cardiology 05/2011; · 6.18 Impact Factor
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    ABSTRACT: Chronic cocaine use may lead to premature atherosclerosis, however, the prevalence of and risk factors for coronary artery disease in asymptomatic cocaine users have not been reported. Between August 2007 and June 2010, 385 African American chronic cocaine users aged 25 to 54 years were consecutively enrolled in a study to investigate the prevalence of CT angiographically-defined significant (≥ 50%) coronary stenosis and related risk factors. Sociodemographic, drug-use behavior, medical history and medication data were obtained by interview and confirmed by medical chart review. Clinical examinations were performed as well as extensive laboratory tests including those for fasting lipid profiles, HIV, high sensitivity C-reactive protein, and vitamin D. Contrast-enhanced coronary CT angiography was performed. Significant coronary stenosis was detected in 52 of 385 participants (13.5%). The prevalences were 12% and 30% in those with low risk and with middle-high risk Framingham score, respectively. In those with low risk scores, the prevalences of significant stenosis were 10% and 18% in those without and with vitamin D deficiency, defined as serum 25-(OH) vitamin D< 10 ng/mL (p=0.08). Multiple logistic regression analysis revealed that vitamin D deficiency (adjusted OR=2.18, 95% CI: 1.07-4.43) is independently associated with the presence of significant coronary stenosis after controlling for traditional risk factors. The study indicates that the prevalence of significant coronary stenoses is high in asymptomatic young and middle-aged African American chronic cocaine users. These findings emphasize the importance of aggressive reduction of risk factors, including vitamin D deficiency in this population.
    International journal of cardiology 02/2011; 158(2):211-6. · 6.18 Impact Factor
  • American Journal of Roentgenology 01/2011; 196(1):4-12. · 2.74 Impact Factor
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    ABSTRACT: PURPOSE We formulated the following PIO (P-patient group, I- intervention/imaging, O-outcome) clinical question: In pregnant patients with right lower quadrant pain, suspected appendicitis, what is the expected sensitivity and specificity of magnetic resonance imaging (MRI) for the diagnosis of acute appendicitis? METHOD AND MATERIALS A systematic search of the literature using PUBMED was performed to identify studies that addressed the clinical question, leading to 42 citations. Subsequent focused review of the literature aimed to investigate the utility of MRI in ruling in or ruling out acute appendicitis in pregnant women with right lower quadrant pain and suspected appendicitis. A total of 6 papers met the inclusion criteria. The studies used MRI criteria for the diagnosis of acute appendicitis that primarily involved the diameter of the appendix and the presence/absence of periappendiceal fat stranding. To obtain summary estimates of sensitivity and specificity, positive predictive value (PPV) and negative predictive value (NPV), and account for a possible correlation between sensitivities and specificities, a bivariate random-effects model was used to perform meta-analysis. The SAS software (version 9.2) was used to perform statistical analysis. RESULTS The pooled sensitivity and specificity and their corresponding 95% confidence interval (CI) derived from the random-effects models are pooled sensitivity 0.91 (95% CI: 0.54, 0.99) and pooled specificity 0.98 (95%CI: 0.87, 0.99). The pooled PPV and NPV and their corresponding 95% CI derived from the random-effects models are pooled PPV 0.86 (95%CI: 0.38, 0.98), and pooled NPV 0.99 (95%CI: 0.93, 0.99). CONCLUSION The diagnostic strength of MRI is in its high specificity and high negative predictive value. Finding a normal appendix on MRI yields high accuracy in excluding acute appendicitis. Since cases of the nonvisualized appendix on MRI pose a diagnostic difficulty, further studies are needed to improve imaging protocols to decrease the incidence of nonvisualized appendix. CLINICAL RELEVANCE/APPLICATION MRI provides a valuable tool for the evaluation of pregnant patients with right lower quadrant pain and can help avoid unnecessary laparatomies and radiation exposure from computed tomography.
    Radiological Society of North America 2010 Scientific Assembly and Annual Meeting; 12/2010
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    ABSTRACT: PURPOSE To determine the prevalence of unsuspected thyroid nodules on MDCT of the chest, in a population of adult outpatients imaged for indications other than thyroid disease. METHOD AND MATERIALS 3077 consecutive adult outpatient's IV contrast enhanced 16- and 64-MDCT scans of the chest were reviewed retrospectively, to identify unsuspected thyroid nodules. Exclusion criteria included history of thyroid cancer, known thyroid nodules or thyroid disease and risk factors for thyroid cancer, as evidenced by their medical records. One of 9 radiologists recorded number of nodules, location and bidirectional measurement of largest nodule, as well as amount of thyroid visualized on the chest CT. Presence of nodule was correlated with age, gender, race and percentage of thyroid imaged. RESULTS Included were 2510 subjects, 1288 men (51.3%) and 1222 (48.7%) women. Mean age was 59.3 years (range 18 - 94 years). Women more frequently had 1 nodule (206/1222 or 16.86% of women vs. 181/1288 or 14.1 % of men) and multiple nodules (167/1222 or 13.7% of women and 75/1288 or 5.8% of men) (p<.0001). There was a significant difference in the mean age of patients with no nodules (57.8 years), 1 nodule (62.4 years) and multiple nodules (66.2 years) (p<0.05). No association was shown with race (p=0.56). One or more nodules were identified in 629 subjects (25.1%). More than half of these subjects had 1 nodule (61.5%, 387/629). Mean maximum diameter was 8.56 mm (standard deviation 6.43 mm, range 1-62 mm). Most nodules were < 1 cm (426 or 67.8%), as opposed to 1 cm or greater (202 or 32.2%). The entire thyroid gland was imaged in 55.3% (1389/2510), more than half of the thyroid gland was imaged in 36.9% (925/2510) and less than half in 7.8% (196/2510). Of the patients who had the entire thyroid imaged (N=1389), nodules were identified in 352 (25.3%), compared to 277/1121 (24.7%) whose thyroid was only partially imaged. Presence of a nodule was not associated with percentage of thyroid imaged (p=0.72). CONCLUSION In this series of adult outpatients, the prevalence of unsuspected thyroid nodules on contrast-enhanced chest CT was 25%. The presence of a nodule was significantly associated with female gender and increasing age. CLINICAL RELEVANCE/APPLICATION By recognizing the frequency of incidental thyroid nodules, the radiologist will better appreciate why a standard approach and reporting of these lesions is so critical.
    Radiological Society of North America 2010 Scientific Assembly and Annual Meeting; 12/2010
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    ABSTRACT: Nonparametric bootstrapping for hierarchical data is relatively underdeveloped and not straightforward: certainly it does not make sense to use simple nonparametric resampling, which treats all observations as independent. We have provided some resampling strategies of hierarchical data, proved that the strategy of nonparametric bootstrapping on the highest level (randomly sampling all other levels without replacement within the highest level selected by randomly sampling the highest levels with replacement) is better than that on lower levels, analyzed real data and performed simulation studies.
    Journal of Applied Statistics 09/2010; 37(9):1487-1498. · 0.45 Impact Factor
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    ABSTRACT: The aim of the study was to assess whether long-term antiretroviral therapy (ART) is associated with the risk of coronary plaques in HIV-infected cardiovascularly asymptomatic African Americans. Between August 2003 and December 2007, 176 HIV-infected cardiovascularly asymptomatic African Americans were consecutively enrolled in an observational study investigating the effects of ART on subclinical atherosclerosis in Baltimore, Maryland. Computed tomography coronary angiography was performed to detect coronary plaques. The overall prevalence rate of coronary plaques was 30%. After adjusting for gender, total cholesterol, and cocaine use, logistic regression analysis revealed that exposure to ART for more than 18 months (adjusted odds ratio [OR]: 2.20, 95% confidence interval [CI]: 1.01, 4.79) was independently associated with the presence of coronary plaques. A higher HIV viral load was univariately associated with the presence of noncalcified plaques. Use of ART (>18 months) was independently associated with the presence of noncalcified plaques (adjusted OR: 7.61, 95% CI: 1.67, 34.7), whereas cocaine use (>15 years) was independently associated with the presence of calcified plaques (adjusted OR: 2.51, 95% CI: 1.11, 5.67). This study suggests that long-term exposure to ART may be associated with coronary plaques. Because long-term use of ART and HIV replication may be associated with the presence of noncalcified plaques, some of which may be more vulnerable to rupture, an intensive lifestyle intervention to reduce traditional risk factors for coronary artery disease (CAD) is ultimately vital to those who are on ART. This study also suggests that cocaine cessation is the single most effective strategy to prevent CAD in HIV-infected cocaine users.
    AIDS patient care and STDs 10/2009; 23(10):815-24. · 2.68 Impact Factor
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    ABSTRACT: To examine the effect of HIV infection on regional left ventricular dysfunction in cardiovascularly asymptomatic individuals. Nineteen HIV-negative and 27 HIV-positive cardiovascularly asymptomatic study participants in Baltimore, Maryland were selected and underwent tagged cardiac magnetic resonance imaging. Regional left ventricular myocardial mid-wall peak systolic circumferential strain (Ecc) and early diastolic strain rate (SRE) of the left ventricle were assessed with the use of the harmonic phase analysis. The average Ecc and SRE measurements were compared between HIV-negative and HIV-positive individuals. Compared with the HIV-negatives, the HIV-positives had lower average Ecc and SRE measurements in 90% of the 16 standard left ventricular segments. Of the 14 segments with decreased Ecc strain, 3 were statistically significant and of 14 with decreased strain rate (SRE), 6 were statistically significant. HIV infection may be associated with subclinical regional left ventricular systolic and diastolic dysfunction in individuals free of overt cardiovascular disease.
    The international journal of cardiovascular imaging 09/2009; 25(8):809-17. · 2.15 Impact Factor
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    ABSTRACT: To investigate whether systemic administration of methamphetamine (METH) induces retinal damage in CD1 mice. Eighteen male CD1 mice were randomly assigned to three groups, six mice per group: Group 1 receiving a single dose of 40 mg/kg METH, Group 2 receiving four doses of 10 mg/kg METH, and Group 3 (control) receiving 40 mg/kg 0.9% NaCl solution. METH and NaCl were administered by intraperitoneal injection. Immunostaining of glial fibrillary acidic protein (GFAP), S-100 for astrocytes and Muller cells, CD11b for microglia, and tyrosine hydroxylase (TH) and TUNEL labeling for apoptotic cell death were performed on the retinal sections on day 1 and day 7 post-exposure. GFAP and S-100 immunoreactivity was observed in Group 1 mice. CD11b+ cells in Group 1 mice showed more intensely stained shorter and thicker cellular processes than Groups 2 and 3, indicating activated microglia in the mice exposed to large-dose METH. No significant difference in TH level was seen among the three groups. TUNEL labeling did not reveal positive cells in the retinas of any of the 18 CD1 mice. A single large dose of METH induces an increase in short-term protein expression of GFAP and S-100 and in microglial activation. The results suggest that METH has a neurotoxic effect on CD1 mouse retina.
    Current eye research 09/2009; 34(9):785-90. · 1.51 Impact Factor

Publication Stats

986 Citations
286.78 Total Impact Points

Institutions

  • 2002–2014
    • Johns Hopkins Medicine
      • Department of Pathology
      Baltimore, Maryland, United States
    • Chinese PLA General Hospital (301 Hospital)
      Peping, Beijing, China
  • 2002–2010
    • Johns Hopkins University
      • • Department of Radiology
      • • Wilmer Eye Institute
      • • Department of Epidemiology
      Baltimore, Maryland, United States
  • 1996–2005
    • University of Miami Miller School of Medicine
      • • Department of Dermatology and Cutaneous Surgery
      • • Department of Epidemiology and Public Health
      • • Department of Urology
      • • Sylvester Comprehensive Cancer Center
      Miami, FL, United States
  • 2001–2002
    • Johns Hopkins Bloomberg School of Public Health
      • Department of Epidemiology
      Baltimore, Maryland, United States
  • 2000
    • University of Miami
      • Department of Epidemiology and Public Health
      كورال غيبلز، فلوريدا, Florida, United States