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4201 citation(s) found for "Chen, Chen".

Abstract A55: A first-in-human, phase I study of an oral hedgehog pathway antagonist, BMS-833923 (XL139), in subjects with advanced or metastatic solid tumors
Papadopoulos, Kyriakos P. , Taylor, Sara , Patnaik, Amita , Chen, Eric X. , Vakkalaguada, Blisse, Lang, Lixin , Ahlers, Christoph M. , Tornout, Jan M. Van , Siu, Lillian L. , Alberts, Steven R. , Tolcher, Anthony W. , Bennett, Kelly Louise

Mayo Clinic

Molecular Cancer Therapeutics | June 27, 2012 | Volume: 8 | Issue: 12_Supplement | Pages: A55-A55

10.1158/1535-7163.targ-09-a55 Get It

Abstract Background: The hedgehog pathway is dysregulated in basal cell carcinoma, medulloblastoma, pancreatic, lung, gastric, and a variety of other cancers. BMS-833923 is a potent, oral, small molecule antagonist of hedgehog signaling. Methods: Subjects with advanced or metastatic solid tumors were enrolled into a multiple ascending dose study to identify a maximum tolerated dose and evaluate safety, tolerability, pharmacokinetics (PK), and pharmacodynamics of BMS-833923. All subjects receive a single dose one week prior to continuous daily dosing. The single dose window allows for single dose PK collection for one week. To identify the pharmacologically active dose range surrogate tissue was collected prior to Day 1 and again on Day 22 of the first cycle. Results: As of August 14, 2009 sixteen subjects have been treated at four dose levels: 30 mg (n=5), 60 mg (n=3), 120 mg (n=3), and 240 mg (n=5); with mean patient age of 56 (range 21–78) and ECOG performance 0–1. No subjects in the first three dose cohorts experienced drug-related CTCAE AEs greater than Grade 2. One subject with medulloblastoma in the 30 mg dose cohort continues on study for more than 10 months with stable disease. Treatment of patients in the fourth cohort at 240 mg continuous daily dosing is still on-going. In this cohort one subject experienced drug-related CTCAE Grade 2 lipase elevation and pancreatitis that quickly resolved when drug was withheld. This subject has a diagnosis of Gorlin Syndrome, which is caused by germline mutations in the hedgehog pathway genes Patched or Smoothened. This subject experienced a partial response (PR) that is still ongoing. BMS-833923 PK properties showed dose proportionality between the 30, 60, and 120 mg dose cohorts with a Cmax of 30 ng/ml, 56 ng/ml and 102 ng/ml respectively. The terminal half-life was greater than 7 days and drug accumulations were observed. Conclusion: BMS-833923 is generally well tolerated at daily doses of 30, 60, 120 mg. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A55.
On Bayesian methods of exploring qualitative interactions for targeted treatment
Chen, Wei , Ghosh, Debashis , Raghunathan, Trivellore E. , Norkin, Maxim , Sargent, Daniel J. , Bepler, Gerold , Sargent, Daniel J

Mayo Clinic

Statistics in Medicine | June 26, 2012 | Volume: 31 | Issue: 28 | Pages: 3693-3707

10.1002/sim.5429 | PMID 22733620 Get It

Providing personalized treatments designed to maximize benefits and minimizing harms is of tremendous current medical interest. One problem in this area is the evaluation of the interaction between the treatment and other predictor variables. Treatment effects in subgroups having the same direction but different magnitudes are called quantitative interactions, whereas those having opposite directions in subgroups are called qualitative interactions (QIs). Identifying QIs is challenging because they are rare and usually unknown among many potential biomarkers. Meanwhile, subgroup analysis reduces the power of hypothesis testing and multiple subgroup analyses inflate the type I error rate. We propose a new Bayesian approach to search for QI in a multiple regression setting with adaptive decision rules. We consider various regression models for the outcome. We illustrate this method in two examples of phase III clinical trials. The algorithm is straightforward and easy to implement using existing software packages. We provide a sample code in Appendix A. Copyright © 2012 John Wiley & Sons, Ltd.
Opposing Effects of Reactive Oxygen Species and Cholesterol on Endothelial Nitric Oxide Synthase and Endothelial Cell Caveolae
Peterson, Timothy E., Poppa, Veronica, Ueba, Hiroto, Chen, Yan , Wu, Albert Y. , Berk, Bradford C.

Mayo Clinic

Circulation Research | June 12, 2012 | Volume: 85 | Issue: 1 | Pages: 29-37

10.1161/01.res.85.1.29 | PMID 10400908 Get It

Abstract—Synthesis of nitric oxide (NO) by endothelial nitric oxide synthase (eNOS) is critical for normal vascular homeostasis. eNOS function is rapidly regulated by agonists and blood flow and chronically by factors that regulate mRNA stability and gene transcription. Recently, localization of eNOS to specialized plasma membrane invaginations termed caveolae has been proposed to be required for maximal eNOS activity. Because caveolae are highly enriched in cholesterol, and hypercholesterolemia is associated with increased NO production, we first studied the effects of cholesterol loading on eNOS localization and NO production in cultured bovine aortic endothelial cells (BAECs). Caveolae-enriched fractions were prepared by OptiPrep gradient density centrifugation. Treatment of BAECs with 30 μg/mL cholesterol for 24 hours stimulated significant increases in total eNOS protein expression (1.50-fold), eNOS associated with caveolae-enriched membranes (2.23-fold), and calcium ionophore-stimulated NO production (1.56-fold). Because reactive oxygen species (ROS) contribute to endothelial dysfunction in hypercholesterolemia, we next studied the effects of ROS on eNOS localization and caveolae number. Treatment of BAECs for 24 hours with 1 μmol/L LY83583, a superoxide-generating napthoquinolinedione, decreased caveolae number measured by electron microscopy and prevented the cholesterol-mediated increases in eNOS expression. In vitro exposure of caveolae-enriched membranes to ROS (xanthine plus xanthine oxidase) dissociated caveolin more readily than eNOS from the membranes. These results show that cholesterol treatment increases eNOS expression, whereas ROS treatment decreases eNOS expression and the association of eNOS with caveolin in caveolae-enriched membranes. Our data suggest that oxidative stress modulates endothelial function by regulating caveolae formation, eNOS expression, and eNOS-caveolin interactions.
Expression and Function of Recombinant Endothelial Nitric Oxide Synthase Gene in Canine Basilar Artery
Chen, Alex F.Y., Tsutsui, Masato , Kinoshita, Hiroyuki , Pompili, Vincent J., Crotty, Thomas B., Spector, David J., Katušić, Zvonimir S. , O’Brien, Timothy

Mayo Clinic

Circulation Research | June 12, 2012 | Volume: 80 | Issue: 3 | Pages: 327-335

10.1161/01.res.80.3.327 | PMID 9048652 Get It

Endothelial NO synthase (eNOS) is an enzyme responsible for the production of a potent vasodilator and a key regulator of vascular tone, NO. In peripheral arteries, expression of a recombinant eNOS gene increases production of NO in the blood vessel wall. This approach appears to be a promising strategy for gene therapy of cerebrovascular disease. The major objective of the present study was to determine whether a recombinant eNOS gene (AdCMVNOS) can be functionally expressed in cerebral arteries. Replication-defective recombinant adenovirus vectors encoding bovine eNOS and Escherichia coli beta-galactosidase (AdCMVLacZ) genes, driven by the cytomegalovirus promoter, were used for ex vivo gene transfer. Rings of canine basilar artery were incubated with increasing titers of the vectors in MEM. Twenty-four or forty-eight hours after gene transfer, expression and function of AdCMVNOS were evaluated by (1) immunohistochemical staining, (2) isometric tension recording, and (3) cGMP radioimmunoassay. Transfection with AdCMVNOS resulted in the expression of recombinant eNOS protein in the vascular adventitia and endothelium, associated with significantly reduced contractile responses to UTP and enhanced endothelium-dependent relaxation to calcium ionophore A23187. Basal production of cGMP was significantly increased in the transfected vessels. The reduced contractions to UTP with increased cGMP production were reversed by a NOS inhibitor, NG-monomethyl-L-arginine. Contractions to UTP or production of cGMP were not affected in arteries transfected with AdCMVLacZ reporter gene. The results of the present study represent the first successful transfer and functional expression of recombinant eNOS gene in cerebral arteries. Our findings suggest that cerebral arterial tone can be modulated by recombinant eNOS expression in the vessel wall. (Circ Res. 1997;80:327-335.)
Renal Response to Acute Neutral Endopeptidase Inhibition in Mild and Severe Experimental Heart Failure
Chen, Horng H. , Schirger, John A., Chau, William, Jougasaki, Michihisa , Lisý, Ondřej, Redfield, Margaret M. , Barclay, Paul T., Burnett, John C.

Mayo Clinic

Circulation | June 12, 2012 | Volume: 100 | Issue: 24 | Pages: 2443-2448

10.1161/01.cir.100.24.2443 | PMID 10595958 Get It

Background—Neutral endopeptidase 24.11 (NEP) is a metalloprotease that is localized in the greatest abundance in the kidney and degrades natriuretic peptides, such as atrial natriuretic peptide (ANP). Mild congestive heart failure (CHF) is characterized by increases in circulating ANP without activation of the renin-angiotensin-aldosterone system (RAAS) or sodium retention. In contrast, severe CHF is characterized by sodium retention and coactivation of both ANP and the RAAS.Methods and Results—We defined the acute cardiorenal actions of the NEP inhibitor candoxatrilat (8 μg · kg−1· min−1) in 4 groups of anesthetized dogs (normal, n=8; mild CHF, n=6; severe CHF, n=5; and severe CHF with chronic AT1receptor antagonism, n=5). Mild CHF was produced by rapid ventricular pacing at 180 bpm for 10 days and severe CHF at 245 bpm for 10 days. In mild CHF, urinary sodium excretion and glomerular filtration rate were greatest in response to acute NEP inhibition compared with the response in either control animals or those with severe CHF. Furthermore, an increase in glomerular filtration rate was observed only in mild CHF in association with increases in renal blood flow and decreases in renal vascular resistance and distal tubular sodium reabsorption. Urinary ANP and cGMP excretion, markers for renal biological actions of ANP, were greatest in mild CHF. The renal actions observed in mild CHF were attenuated in severe CHF and not restored by chronic AT1receptor antagonism.Conclusions—The results of the present study demonstrate that acute NEP inhibition in mild CHF results in marked increases in renal hemodynamics and sodium excretion that exceed that observed in control animals and severe CHF. These studies underscore the potential therapeutic role for NEP inhibition to enhance renal function in mild CHF, an important phase of CHF that is marked by selective activation of endogenous ANP in the absence of an activated RAAS.
Endogenous Natriuretic Peptides Participate in Renal and Humoral Actions of Acute Vasopeptidase Inhibition in Experimental Mild Heart Failure
Chen, Horng H. , Lainchbury, John G., Matsuda, Yuzuru, Harty, Gail J., Burnett, John C.

Mayo Clinic

Hypertension | June 12, 2012 | Volume: 38 | Issue: 2 | Pages: 187-191

10.1161/01.hyp.38.2.187 | PMID 11509474 Get It

Mild heart failure is characterized by increases in atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in the absence of activation of the renin-angiotensin-aldosterone system (RAAS). Vasopeptidase (VP) inhibitors are novel molecules that coinhibit neutral endopeptidase 24.11, which degrades the natriuretic peptides (NPs) and ACE. In a well-characterized canine model of mild heart failure produced by ventricular pacing at 180 bpm for 10 days, we defined the renal and humoral actions of acute VP inhibition with omapatrilat (OMA, n=6) and acute ACE inhibition (n=5) alone with fosinoprilat. We also sought to determine whether the NPs participate in the renal actions of acute VP inhibition by the administration of OMA together with an intrarenal administration of the NP receptor antagonist HS-142-1 (n=5). OMA resulted in a greater natriuretic response than did ACE inhibition in association with increases in plasma cGMP, ANP, BNP, urinary cGMP, urinary ANP excretion, and glomerular filtration rate ( P <0.05 for OMA versus ACE inhibition). Plasma renin activity was increased only in the group subjected to ACE inhibition. Administration of intrarenal HS-142-1 attenuated the renal properties of OMA in association with a decrease in urinary cGMP excretion despite similar increases in plasma ANP and BNP. This study provides new insight into a unique new pharmacological agent that has beneficial renal actions in experimental mild heart failure beyond the actions that are observed with ACE inhibition alone and that are linked to the NP system.
Long-term outcome of patients with depressed left ventricular function undergoing percutaneous transluminal coronary angioplasty. The NHLBI PTCA Registry.
Holmes, D R, Detre, Katherine M., Williams, David O., Kent, K.M. , King, Spencer B., Yeh, Wen‐Chen , Steenkiste, Ann R.

Mayo Clinic

Circulation | June 12, 2012 | Volume: 87 | Issue: 1 | Pages: 21-29

10.1161/01.cir.87.1.21 | PMID 8419010 Get It

BACKGROUND Coronary revascularization with bypass has been shown to improve survival in patients with coronary artery disease and left ventricular dysfunction. In these patients, use of nonsurgical revascularization with percutaneous transluminal coronary angioplasty (PTCA) is increasing, although their long-term outcome has not been well delineated. The purpose of this investigation was to characterize the outcome of angioplasty in patients with decreased left ventricular function and contrast it with the results in patients with normal left ventricular function. METHODS AND RESULTS In the 1985-1986 National Heart, Lung, and Blood Institute's PTCA Registry, of 1,802 patients undergoing PTCA, 244 patients (13.5%) had an ejection fraction of < or = 45% (mean, 39.6 +/- 6.8%). These patients had a higher incidence of prior infarction, a longer and worse history of manifestations of coronary disease, and more extensive coronary artery disease than patients with well-preserved function; 88% and 91%, respectively, had successful dilation of at least one lesion (nonsignificant difference). However, patients with decreased left ventricular function had a decreased frequency of successful dilation of all lesions in which PTCA was attempted (76% versus 84%, p < 0.01). There were no statistically significant differences in in-hospital complications--death occurred in 0.8% and 0.7%, nonfatal myocardial infarction occurred in 4.9% and 4.5%, and emergency surgical revascularization was performed in 4.5% and 3.2%, respectively. Patients were followed for a mean of 4.1 years; during this time, patients with decreased left ventricular function had significantly worse survival and combined event-free survival. Despite this, at 4 years, 87% of the patients with a mean ejection fraction of 39.6% remained alive, and 77% were alive and had not experienced infarction or required bypass. CONCLUSIONS PTCA is effective in selected patients with depressed left ventricular function. Initial outcome and risk-benefit ratio are excellent. Successful dilation of at least one vessel was achieved in 88% of patients with depressed left ventricular function and in 91% of patients with more normal left ventricular function. The former group, however, had a decreased incidence of successful dilation in all lesions in which dilation was attempted (76% versus 84%, p < 0.01). There was no significant difference in in-hospital complications between the two groups. During follow-up, patients with decreased left ventricular function had worse event-free survival, although 77% were alive without infarction or bypass grafting at 4 years.
Long-Term Results of CCG 5942: A Randomized Comparison of Chemotherapy With and Without Radiotherapy for Children With Hodgkin's Lymphoma—A Report From the Children's Oncology Group
Chen, Lu , Kelly, Kara M. , Herzog, P, Gilchrist, Gerald S., Thomson, John W., Sposto, Richard , Hutchinson, Raymond J. , Nachman, James B., Wolden, Suzanne L. , Kadin, Marshall E.

Mayo Clinic

Journal of Clinical Oncology | May 30, 2012 | Volume: 30 | Issue: 26 | Pages: 3174-3180

10.1200/jco.2011.41.1819 | PMID 22649136 Get It

Purpose In 1995, the Children's Cancer Group (CCG) opened a trial for patients with Hodgkin's lymphoma evaluating whether low-dose involved-field radiation therapy (IFRT) improved event-free survival (EFS) for patients achieving a complete response after chemotherapy. We present the long-term study outcome using final data through March 2007. Patients and Methods Between January 1995 and December 1998, 826 eligible patients were enrolled onto CCG 5942. Four hundred ninety-eight patients achieving an initial complete response to chemotherapy were randomly assigned to receive IFRT or no further therapy. EFS and overall survival (OS) were assessed from the date of study entry or random assignment, as appropriate. Results Ten-year EFS and OS rates for the entire cohort were 83.5% and 92.5%, respectively. In an as-treated analysis for randomly assigned patients, the 10-year EFS and OS rates were 91.2% and 97.1%, respectively, for IFRT and 82.9% and 95.9%, respectively, for no further therapy. For EFS and OS comparisons, P = .004 and P = .50, respectively. Bulk disease, “B” symptoms, and nodular sclerosis histology were risk factors for inferior EFS. Conclusion With a median follow-up of 7.7 years, IFRT produced a statistically significant improvement in EFS but no improvement in OS. For individual patients, the relative risks of relapse versus late effects of IFRT must be considered. Patient and disease characteristics and early response assessment will aid in deciding which patients are most likely to benefit from IFRT.
Impairments to the GH-IGF-I Axis in hSOD1G93A Mice Give Insight into Possible Mechanisms of GH Dysregulation in Patients with Amyotrophic Lateral Sclerosis
Steyn, Frederik J. , Ngo, Shyuan T. , Lee, John D. , Leong, J. W., Buckley, A. J., Veldhuis, Johannes D. , McCombe, Pamela , Chen, Chen , Bellingham, Mark C. , Steyn, F J , Chen, C , Bellingham, Mark C

Mayo Clinic

Endocrinology | May 24, 2012 | Volume: 153 | Issue: 8 | Pages: 3735-3746

10.1210/en.2011-2171 | PMID 22621959 Get It

GH deficiency has been found in subjects with amyotrophic lateral sclerosis (ALS). Disrupted endocrine function could contribute to the progressive muscle loss and hypermetabolism seen in ALS. It is not possible to study all the elements of the GH-IGF-I axis in ALS patients. Consequently, it remains unclear whether dysfunctional GH secretion contributes to disease pathogenesis and why GH and IGF-I directed treatment strategies are ineffective in human ALS. The hSOD1G93A transgenic mouse model is useful for the detailed investigation of the pathogenesis of ALS. We report that symptomatic male hSOD1G93A transgenic mice exhibit a deficiency in GH secretion similar to that seen in human ALS. Further characterization of the GH-IGF-I axis in hSOD1G93A mice reveals central and peripheral abnormalities that are not found in wild-type age-matched controls. Specifically, we observe aberrant endogenous pulsatile GH secretion, reduced pituitary GH content, and decreased circulating levels of IGF-I, indicating global GH deficiency in hSOD1G93A mice. Furthermore, a reduction in the expression of the IGF-I receptor α-subunit in skeletal muscle and lumbar spinal cords of hSOD1G93A mice suggests impaired IGF-I signaling within these tissues. This is the first account of disrupted GH secretion in a transgenic mouse model of ALS. These observations are essential for the development of effective GH and IGF-I targeted therapies in ALS.