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7542 citation(s) found for "Ho, Matthew".

Analysis of mode vibrations of arteries for estimation of elastic properties.
Nenadic, Ivan , Greenleaf, James F., Urban, Matthew W. , Bernal, Miguel

Mayo Clinic

The Journal of the Acoustical Society of America | October 19, 2010 | Volume: 128 | Issue: 4_Supplement | Pages: 2363-2363

10.1121/1.3508389 Get It

Arterial elasticity has gained importance in the past decades as it has been shown to be an independent predictor of cardiovascular diseases. Ultrasound radiation force has been used to excite propagating waves in arterial vessels in order to measure the wave speeds and characterize the elastic properties of the vessels. Excised pig carotid arteries were excited with impulsive radiation force using 3-MHz tonebursts of length 200, and the propagating waves were measured along the length of the artery over a distance of 2 cm. A 2-D fast Fourier transform was performed on the spatiotemporal data for identification of several propagating modes in the vessel. Multiple propagating modes could be visualized from the spatiotemporal data that varied with the transmural pressure of the artery under investigation over a range of 10–100 mm Hg. The modes present in the data were fitted with a theoretical model to estimate the elasticity of the arteries. The comparison with the model provides insight into characterizing the elastic properties of the artery. [This work was supported in part by NIH Grant no. EB002640.]
Vibro-acoustography with rotational liner array transducer.
Urban, Matthew W. , Alizad, Azra , Fatemi, Mostafa , Urban, Matthew W

Mayo Clinic

The Journal of the Acoustical Society of America | October 19, 2010 | Volume: 128 | Issue: 4_Supplement | Pages: 2363-2363

10.1121/1.3508388 Get It

Vibro-acoustography with rectilinear raster scanning using confocal or linear array transducers have been reported before. Endo-cavity imaging requires a different type of scanning due to space limitation. This paper describes 3-D endo-cavity vibro-acoustography by a rotating linear array that scans the volume of interest. In this configuration a linear array is used to steer the beam electronically, which is combined with the rotational motion of the transducer to scan the beam in a cylindrical volume. This particular geometry produces special artifacts in the image. One such artifact is non-uniformity in signal power due to angular variations with respect to the hydrophone. Another artifact is related to the geometrical distortion in the image. In this paper, we will present examples of vibro-acoustography images with linear and rotational scanning and describe image characteristics and methods to reduce the artifacts. [Work supported by NIH Grant P50 CA91956P2.]
Generalized response of a sphere embedded in a viscoelastic medium excited by ultrasound radiation force.
Urban, Matthew W. , Nenadic, Ivan , Greenleaf, James F. , Chen, Shigao , Urban, Matthew W

Mayo Clinic

The Journal of the Acoustical Society of America | October 19, 2010 | Volume: 128 | Issue: 4_Supplement | Pages: 2337-2337

10.1121/1.3508269 Get It

Characterization of viscoelastic soft tissues and materials has been a subject of active research for the past two decades. Techniques involving measuring the motion of embedded spheres in viscoelastic media have been employed to measure the viscoelastic material properties of the media surrounding the sphere. The published work using this technique has been restricted to using the Kelvin–Voigt model, which has worked for gelatin-based materials. We report an extension of this method using different viscoelastic rheological models such as the Maxwell, generalized Maxwell, Zener, and Kelvin–Voigt fractional derivative models. We performed experiments using a focused 3-MHz transducer to produce radiation force and a 7.5-MHz pulse-echo transducer to measure the sphere motion. Two phantoms were tested; one made of gelatin and another made of rubber with stainless steel spheres embedded in the materials. The response was fitted with the generalized theoretical model to find the material properties over bandwidths of 25–3000 Hz. The median absolute errors ranged from 0.0036–0.0421 and 0.0365–0.0879 for the gelatin and rubber phantoms, respectively. This generalized method offers added flexibility to characterize different types of viscoelastic materials using the most appropriate rheological model. [Work supported in part by NIH Grant nos. EB002167 and DK082408.]
Improving Risk Assessment in Family Medicine Through the Family History
Bernard, Matthew , Zabel, Carrie, Rohrer, James E.

Mayo Clinic

Journal of Primary Care & Community Health | September 30, 2010 | Volume: 1 | Issue: 3 | Pages: 147-151

10.1177/2150131910375841 | PMID 23804602 Get It

The family history is used as a screening tool to identify persons who may be at risk for a heritable disorder. Primary care providers sometimes do not thoroughly gather and document the family history. This pilot study was undertaken to determine whether having a genetic counselor on site at our family medicine clinic 2 days a week for 3 months would improve the quality of the family history field in patient records. We compared 7 elements in the family history field for patients seen before and after the genetic counselor was on site. Documentation of 1 of the 7 elements (major disease) improved significantly after the intervention period ( P = .02). Changing provider behavior with regard to gathering and documenting family history of major disease may be facilitated by tools to help collect the family history and by using the increasing number of available genetic tests.
TROY (TNFRSF19) Is Overexpressed in Advanced Glial Tumors and Promotes Glioblastoma Cell Invasion via Pyk2-Rac1 Signaling
Paulino, Vincent M., Kloss, Jean , Ennis, Matthew, Armstrong, Brock , Loftus, Joseph C. , Tran, Nhan L. , Yang, Zhongbo , Tran, Nhan L

Mayo Clinic

Molecular Cancer Research | September 30, 2010 | Volume: 8 | Issue: 11 | Pages: 1558-1567

10.1158/1541-7786.mcr-10-0334 | PMID 20881009 Get It

Abstract A critical problem in the treatment of malignant gliomas is the extensive infiltration of individual tumor cells into adjacent brain tissues. This invasive phenotype severely limits all current therapies, and to date, no treatment is available to control the spread of this disease. Members of the tumor necrosis factor (TNF) ligand superfamily and their cognate receptors regulate various cellular responses including proliferation, migration, differentiation, and apoptosis. Specifically, the TNFRSF19/TROY gene encodes a type I cell surface receptor that is expressed on migrating or proliferating progenitor cells of the hippocampus, thalamus, and cerebral cortex. Here, we show that levels of TROY mRNA expression directly correlate with increasing glial tumor grade. Among malignant gliomas, TROY expression correlates inversely with overall patient survival. In addition, we show that TROY overexpression in glioma cells activates Rac1 signaling in a Pyk2-dependent manner to drive glioma cell invasion and migration. Pyk2 coimmunoprecipitates with the TROY receptor, and depletion of Pyk2 expression by short hairpin RNA interference oligonucleotides inhibits TROY-induced Rac1 activation and subsequent cellular migration. These findings position aberrant expression and/or signaling by TROY as a contributor, and possibly as a driver, of the malignant dispersion of glioma cells. Mol Cancer Res; 8(11); 1558–67. ©2010 AACR.
Genome-Wide Associations and Functional Genomic Studies of Musculoskeletal Adverse Events in Women Receiving Aromatase Inhibitors
Schaid, Daniel J. , Goss, Paul E., Liu, Mohan , Chapman, Judy-Anne W., Kubo, Michiaki , Jenkins, Gregory D. , Batzler, Anthony , Shepherd, Lois E. , Pater, Joseph L. , Wang, Liewei , Stearns, Vered , Rohrer, Daniel C. , Pritchard, Kathleen I. , Flockhart, David A., Nakamura, Yusuke , Weinshilboum, Richard M. , Ingle, James N. , Mushiroda, Taisei , Chapman, Judy‐Anne W., Ellis, Matthew J. , Goetz, Matthew P. , Weinshilboum, Richard M. , Stearns, Vered

Mayo Clinic

Journal of Clinical Oncology | September 28, 2010 | Volume: 28 | Issue: 31 | Pages: 4674-4682

10.1200/jco.2010.28.5064 | PMID 20876420 Get It

Purpose We performed a case-control genome-wide association study (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with musculoskeletal adverse events (MS-AEs) in women treated with aromatase inhibitors (AIs) for early breast cancer. Patients and Methods A nested case-control design was used to select patients enrolled onto the MA.27 phase III trial comparing anastrozole with exemestane. Cases were matched to two controls and were defined as patients with grade 3 or 4 MS-AEs (according to the National Cancer Institute's Common Terminology Criteria for Adverse Events v3.0) or those who discontinued treatment for any grade of MS-AE within the first 2 years. Genotyping was performed with the Illumina Human610-Quad BeadChip. Results The GWAS included 293 cases and 585 controls. A total of 551,358 SNPs were analyzed, followed by imputation and fine mapping of a region of interest on chromosome 14. Four SNPs on chromosome 14 had the lowest P values (2.23E-06 to 6.67E-07). T-cell leukemia 1A (TCL1A) was the gene closest (926-7000 bp) to the four SNPs. Functional genomic studies revealed that one of these SNPs (rs11849538) created an estrogen response element and that TCL1A expression was estrogen dependent, was associated with the variant SNP genotypes in estradiol-treated lymphoblastoid cells transfected with estrogen receptor alpha and was directly related to interleukin 17 receptor A (IL17RA) expression. Conclusion This GWAS identified SNPs associated with MS-AEs in women treated with AIs and with a gene (TCL1A) which, in turn, was related to a cytokine (IL17). These findings provide a focus for further research to identify patients at risk for MS-AEs and to explore the mechanisms for these adverse events.
Multiplex Detection of IgM and IgG Class Antibodies toToxoplasma gondii, Rubella Virus, and Cytomegalovirus Using a Novel Multiplex Flow Immunoassay
Binnicker, Matthew J. , Jespersen, Deborah J., Harring, Julie

Mayo Clinic

Clinical and Vaccine Immunology | September 23, 2010 | Volume: 17 | Issue: 11 | Pages: 1734-1738

10.1128/cvi.00332-10 | PMID 20861325 Get It

ABSTRACTThe goal of this study was to evaluate the BioPlex 2200Toxoplasma, rubella, and cytomegalovirus (CMV) (ToRC) IgG and IgM multiplex immunoassays (Bio-Rad Laboratories, Hercules, CA) and compare the results to those of conventional testing by enzyme immunoassay (EIA) and enzyme-linked fluorescent assay (ELFA). Serum specimens (n= 600) submitted for routine ToRC IgG and IgM testing by EIA (SeraQuest, Doral, FL; Diamedix, Miami, FL) or ELFA (Vidas; bioMérieux, Durham, NC) were also tested by the BioPlex ToRC multiplex immunoassays. Samples showing discordant results were retested by both methods, with further discrepancies being arbitrated by a third assay. Following repeat testing, the BioPlexToxoplasma, rubella, and CMV IgG assays demonstrated agreements of 98.7 (592/600 specimens), 93.3 (560/600 specimens), and 98.3% (590/600 specimens), respectively, while the ToRC IgM assays yielded agreements of 91.2 (547/600 specimens), 87.3 (524/600 specimens), and 95.2% (571/600 specimens), respectively. The BioPlex ToRC IgG assays provided results comparable to EIA/ELFA results, with kappa coefficients showing near-perfect agreement for theToxoplasma(κ = 0.94) and CMV (κ = 0.97) IgG assays and substantial agreement for the rubella IgG assay (κ = 0.66). The BioPlex ToRC IgM assays showed lower specificity with only slight agreement forToxoplasmaIgM (κ = 0.07), poor agreement for rubella IgM (κ = −0.03), and moderate agreement for CMV IgM (κ = 0.55). Both the BioPlex IgG and IgM assays reduced turnaround time (1.7 h versus 5.5 h by EIA/ELFA for 100 specimens) and eliminated the necessity to manually pipette or aliquot specimens prior to testing.
Reply to J.R. Carver et al
Nowakowski, Grzegorz S. , Maurer, Matthew J. , Witzig, Thomas E. , Cerhan, James R. , Maurer, Matthew

Mayo Clinic

Journal of Clinical Oncology | August 31, 2010 | Volume: 28 | Issue: 30 | Pages: e612-e612

10.1200/jco.2010.30.2752 Get It

Clinical Neuroradiology: A Case-Based Approach
Morris, Matthew W.

Mayo Clinic

American Journal of Roentgenology | August 20, 2010 | Volume: 195 | Issue: 3 | Pages: W260-W261

10.2214/ajr.10.4330 Get It