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3501 citation(s) found for "Xu, Timothy".

Fat depot origin affects adipogenesis in primary cultured and cloned human preadipocytes
Giorgadze, Nino, Pirtskhalava, Tamar , Καραγιαννίδης, Ιορδάνης, Forse, R. Armour , DePonte, Matthew, Stevenson, Michael , Guo, Wen , Han, Jianrong, Waloga, Gerri, Lash, Timothy L. , Jensen, Michael D. , Kirkland, James L. , Tchkonia, Tamar , Tchoukalova, Yourka D.

American Journal of Physiology-Regulatory, Integrative and Comparative Physiology | March 3, 2015 | Volume: 282 | Issue: 5 | Pages: R1286-R1296

10.1152/ajpregu.00653.2001 | PMID 11959668 Get It

Fat distribution varies among individuals with similar body fat content. Innate differences in adipose cell characteristics may contribute because lipid accumulation and lipogenic enzyme activities vary among preadipocytes cultured from different fat depots. We determined expression of the adipogenic transcription factors peroxisome proliferator activated receptor-γ (PPAR-γ) and CCAAT/enhancer binding protein-α (C/EBP-α) and their targets in abdominal subcutaneous, mesenteric, and omental preadipocytes cultured in parallel from obese subjects. Subcutaneous preadipocytes, which had the highest lipid accumulation, glycerol-3-phosphate dehydrogenase (G3PD) activity, and adipocyte fatty acid binding protein (aP2) abundance, had highest PPAR-γ and C/EBP-α expression. Levels were intermediate in mesenteric and lowest in omental preadipocytes. Overexpression of C/EBP-α in transfected omental preadipocytes enhanced differentiation. The proportion of differentiated cells in colonies derived from single subcutaneous preadipocytes was higher than in mesenteric or omental clones. Only cells that acquired lipid inclusions exhibited C/EBP-α upregulation, irrespective of depot origin. Thus regional variation in adipogenesis depends on differences at the level of transcription factor expression and is a trait conferred on daughter cells.
Inhibitory effect of recombinant iNOS gene expression on vasomotor function of canine basilar artery
Eguchi, Daihiko , Wambi, Chris, Weiler, Deborah A., Kovesdi, Imre , Katušić, Zvonimir S. , d’Uscio, Livius V. , O’Brien, Timothy

American Journal of Physiology-Heart and Circulatory Physiology | March 3, 2015 | Volume: 283 | Issue: 6 | Pages: H2560-H2566

10.1152/ajpheart.00415.2002 | PMID 12388312 Get It

The present study was designed to determine the effect of recombinant inducible nitric oxide (NO) synthase (iNOS) gene expression on vasomotor function in cerebral arteries. Isolated canine basilar arteries were exposed ex vivo (30 min at 37°C) to an adenoviral vector [107, 108, or 109plaque-forming units (pfu)/ml] encoding either the iNOS gene or the β-galactosidase reporter gene. Twenty-four hours after transduction, Western blot analysis demonstrated expression of iNOS protein only in iNOS (109pfu/ml)-transduced arteries. Immunohistochemical analysis localized iNOS expression predominantly in adventitia. Vascular reactivity of isolated basilar arteries was studied by isometric force recording. Concentration-response curves to UTP (10−9–10−3M) and diethylaminodiazen-1-ium-1,2-dioate (10−10–10−5M) were significantly shifted to the right in iNOS gene (109pfu/ml)-transduced rings compared with control and β-galactosidase-transduced rings ( P < 0.05, n = 5–6). Endothelium-dependent relaxation to bradykinin was significantly attenuated in iNOS-transduced rings ( P < 0.001, n = 8). The basal level of cGMP and superoxide anion (O[Formula: see text]·) production were elevated in iNOS-transduced rings ( P < 0.05, n = 7 for cGMP; P < 0.01, n = 6–9 for O[Formula: see text]· production). Our results suggest that expression of recombinant iNOS in cerebral arteries reduces vasomotor reactivity to both vasoconstrictor and vasodilator agonists. Attenuation of contractions is most likely due to functional antagonism between UTP and cGMP. Reduction of endothelium-dependent relaxation to bradykinin appears to be mediated in part by reduced reactivity of smooth muscle cells to NO.
Adenoviral-mediated overexpression of catalase inhibits endothelial cell proliferation
Katušić, Zvonimir S. , Zanetti, Michela , O’Brien, Timothy

American Journal of Physiology-Heart and Circulatory Physiology | March 3, 2015 | Volume: 283 | Issue: 6 | Pages: H2620-H2626

10.1152/ajpheart.00358.2001 | PMID 12427601 Get It

Although hydrogen peroxide (H2O2) induces proliferation of vascular smooth muscle cells, its role in endothelial cell proliferation is unclear. Our aim was to study the role of hydrogen peroxide in endothelial cell proliferation by overexpressing catalase. Human aortic endothelial cells were transduced with adenoviral vectors encoding β-galactosidase (Adβgal) or catalase (AdCat) or were exposed to diluent alone (control). Transgene expression was demonstrated by β-galactosidase staining, Western analysis, and significantly increased enzyme activity in AdCat-transduced cells. Overexpression of catalase decreased DNA synthesis in AdCat compared with control and Adβgal-transduced cells (536.8 ± 31 vs. 1,875.1 ± 132.9 vs. 1,347.5 ± 93.7 dpm/well, respectively; P < 0.05 vs. control and Adβgal). Six days after transduction with AdCat (multiplicity of infection = 50), cell numbers were significantly reduced (AdCat: 38 ± 1.8% of cell counts in control, P < 0.05; and 45 ± 2% of cell count in Adβgal, P < 0.05). Incubation with aminotriazole 10 mmol/l, an inhibitor of catalase, prevented this effect. The number of apoptotic cells was increased one- and threefold 2 and 4 days, respectively, after transduction with AdCat. Exogenous administration of low concentrations of H2O2(50 μM) significantly increased cell proliferation, whereas it was inhibited by higher concentrations. These results suggest that H2O2is an important modulator of endothelial cell proliferation.
Treatment Planning and Fracture Prediction in Patients with Skeletal Metastasis with CT-Based Rigidity Analysis
Entezari, Vahid , Calderon, Nathan, Hipp, John A. , Villa‐Camacho, Juan C., Cheung, Felix H., Aboulafia, Albert J. , Turcotte, Robert , Anderson, Megan E. , Gebhardt, Mark C., Terek, Richard M. , Yaszemski, Michael J. , Snyder, Brian D. , Yaszemski, Michael, Nazarian, Ara , Zurakowski, David , Lin, Patrick P. , Cheng, Edward Y. , Damron, Timothy A.

Clinical Cancer Research | February 27, 2015 | Volume: 21 | Issue: 11 | Pages: 2514-2519

10.1158/1078-0432.ccr-14-2668 | PMID 25724521 Get It

Abstract Purpose: Pathologic fractures could be prevented if reliable methods of fracture risk assessment were available. A multicenter prospective study was conducted to identify significant predictors of physicians' treatment plan for skeletal metastasis based on clinical fracture risk assessments and the proposed CT-based Rigidity Analysis (CTRA). Experimental Design: Orthopedic oncologists selected a treatment plan for 124 patients with 149 metastatic lesions based on the Mirels method. Then, CTRA was performed, and the results were provided to the physicians, who were asked to reassess their treatment plan. The pre- and post-CTRA treatment plans were compared to identify cases in which the treatment plan was changed based on the CTRA report. Patients were followed for a 4-month period to establish the incidence of pathologic fractures. Results: Pain, lesion type, and lesion size were significant predictors of the pre-CTRA plan. After providing the CTRA results, physicians changed their plan for 36 patients. CTRA results, pain, and primary source of metastasis were significant predictors of the post-CTRA plan. Follow-up of patients who did not undergo fixation resulted in 7 fractures; CTRA predicted these fractures with 100% sensitivity and 90% specificity, whereas the Mirels method was 71% sensitive and 50% specific. Conclusions: Lesion type and size and pain level influenced the physicians' plans for the management of metastatic lesions. Physicians' treatment plans and fracture risk predictions were significantly influenced by the availability of CTRA results. Due to its high sensitivity and specificity, CTRA could potentially be used as a screening method for pathologic fractures. Clin Cancer Res; 21(11); 2514–9. ©2015 AACR.
Exome sequencing establishes diagnosis of Alström syndrome in an infant presenting with non‐syndromic dilated cardiomyopathy
Long, Pamela A., Evans, Jared M., Olson, Timothy M. , Olson, Timothy M

American Journal of Medical Genetics Part A | February 23, 2015 | Volume: 167 | Issue: 4 | Pages: 886-890

10.1002/ajmg.a.36994 | PMID 25706677 Get It

Idiopathic dilated cardiomyopathy is a heritable, genetically heterogeneous disorder characterized by progressive heart failure. Dilated cardiomyopathy typically exhibits autosomal dominant inheritance, yet frequently remains clinically silent until adulthood. We sought to discover the molecular basis of idiopathic, non‐syndromic dilated cardiomyopathy in a one‐month‐old male presenting with severe heart failure. Previous comprehensive testing of blood, urine, and skin biopsy specimen was negative for metabolic, mitochondrial, storage, and infectious etiologies. Ophthalmologic examination was normal. Chromosomal microarray and commercial dilated cardiomyopathy gene panel testing failed to identify a causative mutation. Parental screening echocardiograms revealed no evidence of clinically silent dilated cardiomyopathy. Whole exome sequencing was carried out on the family trio on a research basis, filtering for rare, deleterious, recessive and de novo genetic variants. Pathogenic compound heterozygous truncating mutations were identified in ALMS1, diagnostic of Alström syndrome and prompting disclosure of genetic findings. Alström syndrome is a known cause for dilated cardiomyopathy in children yet delayed and mis‐diagnosis are common owing to its rarity and age‐dependent emergence of multisystem clinical manifestations. At six months of age the patient ultimately developed bilateral nystagmus and hyperopia, features characteristic of the syndrome. Early diagnosis is guiding clinical monitoring of other organ systems and allowing for presymptomatic intervention. Furthermore, recognition of recessive inheritance as the mechanism for sporadic disease has informed family planning. This case highlights a limitation of standard gene testing panels for pediatric dilated cardiomyopathy and exemplifies the potential for whole exome sequencing to solve a diagnostic dilemma and enable personalized care. © 2015 Wiley Periodicals, Inc.
Trochanteric Micropuncture: Treatment for Gluteus Medius Tendinopathy
Redmond, John M., Cregar, William M., Gupta, Asheesh, Hammarstedt, Jon E. , Martin, Timothy J. , Domb, Benjamin G.

Arthroscopy Techniques | February 23, 2015 | Volume: 4 | Issue: 1 | Pages: No page available

10.1016/j.eats.2014.11.009 | PMID 25973381 Get It

Abstract Lateral hip pain along with tenderness of the greater trochanter has been associated with greater trochanteric pain syndrome. Radiographically, this has been associated with gluteus medius pathology on magnetic resonance imaging. This has led some surgeons to conclude that abductor pathology is a primary cause of lateral hip pain. Failure of conservative treatment in the setting of gluteus medius pathology may lead to surgical intervention. In some patients a focal tear of the gluteus medius cannot be visualized and likely represents more diffuse tendinopathy. In these patients we propose micropuncture of the greater trochanter. Similar procedures have shown effectiveness in the elbow and shoulder by eliciting a healing response. Our experience suggests that trochanteric micropuncture at the insertion of the gluteus medius tendon can be effectively performed endoscopically for gluteus medius tendinopathy. Technique Video video See video under supplementary data.
Association of Branched and Aromatic Amino Acids Levels with Metabolic Syndrome and Impaired Fasting Glucose in Hypertensive Patients
Weng, Liming, Quinlivan, Eoin P. , Beitelshees, Amber L. , Shahin, Mohamed H. , Chapman, Arlene B. , Gums, John G. , Johnson, Julie A. , Frye, Reginald F. , Beitelshees, Amber L. , Gong, Yan , Turner, Stephen T. , Garrett, Timothy J. , Cooper‐DeHoff, Rhonda M.

Metabolic Syndrome and Related Disorders | February 9, 2015 | Volume: 13 | Issue: 5 | Pages: 195-202

10.1089/met.2014.0132 | PMID 25664967 Get It

Reply to reflection on MUNE
Gooch, Clifton L. , Doherty, Timothy J., Chan, K. Ming , Bromberg, Mark B. , Lewis, Richard A. , Stashuk, Dan, Berger, Michael , Andary, Michael , Daube, Jasper R.

Muscle & Nerve | January 24, 2015 | Volume: 51 | Issue: 4 | Pages: 624-624

10.1002/mus.24585 | PMID 25620429 Get It

Right and Left Atrial Dissimilarities in Normal Subjects Explored by Speckle Tracking Echocardiography
Moustafa, Sherif, Zuhairy, Hamed, Youssef, Mostafa , Alvarez, Nanette, Connelly, Michael S. , Prieur, Timothy, Mookadam, Farouk

Echocardiography | January 22, 2015 | Volume: 32 | Issue: 9 | Pages: 1392-1399

10.1111/echo.12880 | PMID 25611312 Get It

BackgroundAtrial function is an important contributor of ventricular function and has a prognostic role in various cardiovascular diseases. We tested the hypothesis that right and left atrial (RA & LA) function may not be equal despite their accommodating identical cardiac output.MethodsTwo‐dimensional (2D) speckle tracking echocardiography was acquired from the apical four‐chamber view in 100 normal subjects. Both RA/LA subendocardial borders were traced to obtain atrial volumes, strain (ε) and strain rate (SR). Reservoir, conduit, and booster pump functions were evaluated. Consequently, εNeg (corresponding to pump function) and εPos (corresponding to conduit function) were gauged. The SR parameters (SRLateNeg, SRPos, and SREarlyNeg), corresponding respectively to atrial systole, inception of ventricular systole, and inception of ventricular diastole, were measured.ResultsMean age was 39 ± 15 years with 50 men (50%). Volumetric indices revealed that reservoir (Filling Volume = 35.1 ± 10.4 mL for LA vs. 27.47 ± 11.93 mL for RA, expansion index = 52.18 ± 16.89% for LA vs. 45.03 ± 16.49% for RA and diastolic emptying index = 52.85 ± 16.85 for LA vs. 45.62 ± 16.5 for RA, P < 0.001) and conduit (passive emptying (%) of total emptying = 34.49 ± 10.4 for LA vs. 26.82 ± 11.98 for RA and passive emptying index = 52.63 ± 16.86 for LA vs. 45.39 ± 16.5 for RA, P < 0.001) functions were significantly higher in the LA compared to the RA. Nevertheless, deformation indices demonstrated an opposite pattern (SRpos = 1.88 ± 0.74 for RA vs. 1.56 ± 0.54 for LA, P = 0.03 and εPos = 59.56 ± 30.63 for RA vs. 45.94 ± 16.67 for LA, P < 0.001). Reservoir, conduit, and booster pump functions showed no statistical significance among both genders.ConclusionsEvaluation of global and regional RA/LA function by speckle tracking echocardiography is feasible. The current report provides insights regarding dissimilarities between both atria in healthy individuals. The significance of these findings and their potential application will warrant further work.
Identification of Susceptibility Loci in IL6 , RPS9 / LILRB3 , and an Intergenic Locus on Chromosome 21q22 in Takay
Saruhan‐Direskeneli, Güher , Coit, Patrick , Adler, Adam, Aksu, Kenan , Alıbaz-Öner, Fatma , Aydın, Sibel Zehra , Kamalı, Sevil , Carette, Simon , Cuthbertson, David , Hoffman, Gary S., Önen, Fatoş , Akkoç, Nurullah , Koening, Curry L. , Karadağ, Ömer , Kiraz, Sedat , Langford, Carol A. , Maksimowicz‐McKinnon, Kathleen , McAlear, Carol A. , Özbalkan, Zeynep, Ateş, Aşkın , Karaaslan, Yaşar , Düzgün, Nurşen , Özer, Hüseyin , Erken, Eren , Öztürk, Mehmet Akif , Yazıcı, Ayten , Çefle, Ayşe , Onat, Ahmet Mesut , Kısacık, Bünyamin , Kaşifoğlu, Timuçin , Fresko, İzzet , Seo, Philip , Sreih, Antoine G. , Warrington, Kenneth J. , Ytterberg, Steven R. , Çobankara, Veli , Cunninghame‐Graham, Deborah S., Vyse, Timothy J. , Pamuk, Ömer Nuri̇ , Tunç, Şevket Ercan , Dalkılıç, Ediz , Bıçakçıgil, Müge, Yentür, Sibel P., Wren, Jonathan D. , Sawalha, Amr H. , Renauer, Paul A. , Keser, Gökhan , İnanç, Murat , Akar, Servet , Khalidi, Nader , Monach, Paul A. , Pagnoux, Christian , Seyahi, Emire , Merkel, Peter A. , Di̇reskeneli̇, Haner , Warrington, Kenneth J

Arthritis & Rheumatology | January 20, 2015 | Volume: 67 | Issue: 5 | Pages: 1361-1368

10.1002/art.39035 | PMID 25604533 Get It

Objective Takayasu arteritis is a rare large vessel vasculitis with incompletely understood etiology. This study was undertaken to perform the first unbiased genome‐wide association analysis of Takayasu arteritis. Methods Two independent cohorts of patients with Takayasu arteritis from Turkey and North America were included in our study. The Turkish cohort consisted of 559 patients and 489 controls, and the North American cohort consisted of 134 patients and 1,047 controls of European ancestry. Genotyping was performed using the Omni1‐Quad and Omni2.5 genotyping arrays. Genotyping data were subjected to rigorous quality control measures and subsequently analyzed to discover genetic susceptibility loci for Takayasu arteritis. Results We identified genetic susceptibility loci for Takayasu arteritis with a genome‐wide level of significance in IL6 (rs2069837) (odds ratio [OR] 2.07, P = 6.70 × 10 −9 ), RPS9 / LILRB3 (rs11666543) (OR 1.65, P = 2.34 × 10 −8 ), and an intergenic locus on chromosome 21q22 (rs2836878) (OR 1.79, P = 3.62 × 10 −10 ). The genetic susceptibility locus in RPS9 / LILRB3 lies within the leukocyte receptor complex gene cluster on chromosome 19q13.4, and the disease risk variant in this locus correlates with reduced expression of multiple genes including the inhibitory leukocyte immunoglobulin‐like receptor gene LILRB3 ( P = 2.29 × 10 −8 ). In addition, we identified candidate susceptibility genes with suggestive levels of association ( P < 1 × 10 −5 ) with Takayasu arteritis, including PCSK5, LILRA3, PPM1G/NRBP1 , and PTK2B . Conclusion Our findings indicate novel genetic susceptibility loci for Takayasu arteritis and uncover potentially important aspects of the pathophysiology of this form of vasculitis.