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2094 citation(s) found for "Xu, Vincent".

Long-Term Biological Variation of Serum Protein Electrophoresis M-Spike, Urine M-Spike, and Monoclonal Serum Free Light Chain Quantification: Implications for Monitoring Monoclonal Gammopathies
Katzmann, Jerry A., Snyder, Melissa R, Rajkumar, S. Vincent , Kyle, Robert A. , Therneau, Terry M. , Benson, Joanne T., Dispenzieri, Angela , Snyder, Melissa R, Rajkumar, S Vincent , Dispenzieri, Angela

Clinical Chemistry | October 7, 2011 | Volume: 57 | Issue: 12 | Pages: 1687-1692

10.1373/clinchem.2011.171314 | PMID 21980167 Get It

BACKGROUND We analyzed serial data in patients with clinically stable monoclonal gammopathy to determine the total variation of serum M-spikes [measured with serum protein electrophoresis (SPEP)], urine M-spikes [measured with urine protein electrophoresis (UPEP)], and monoclonal serum free light chain (FLC) concentrations measured with immunoassay. METHODS Patients to be studied were identified by (a) no treatment during the study interval, (b) no change in diagnosis and <5 g/L change in serum M-spike over the course of observation; (c) performance of all 3 tests (SPEP, UPEP, FLC immunoassay) in at least 3 serial samples that were obtained 9 months to 5 years apart; (d) serum M-spike ≥10 g/L, urine M-spike ≥200 mg/24 h, or clonal FLC ≥100 mg/L. The total CV was calculated for each method. RESULTS Among the cohort of 158 patients, 90 had measurable serum M-spikes, 25 had urine M-spikes, and 52 had measurable serum FLC abnormalities. The CVs were calculated for serial SPEP M-spikes (8.1%), UPEP M-spikes (35.8%), and serum FLC concentrations (28.4%). Combining these CVs and the interassay analytical CVs, we calculated the biological CV for the serum M-spike (7.8%), urine M-spike (35.5%), and serum FLC concentration (27.8%). CONCLUSIONS The variations in urine M-spike and serum FLC measurements during patient monitoring are similar and are larger than those for serum M-spikes. In addition, in this group of stable patients, a measurable serum FLC concentration was available twice as often as a measurable urine M-spike.
Learning Curve of Robotic-Assisted Microvascular Anastomosis in the Rat
Mattar, Tiago Guedes da Motta , Parisi, Thomas J., Carlsen, Brian T. , Shin, Alexander Y. , Lee, Joo‐Yup , Bishop, Allen T. , Shin, Alexander Y

Journal of Reconstructive Microsurgery | September 30, 2011 | Volume: 28 | Issue: 07 | Pages: 451-456

10.1055/s-0031-1289166 | PMID 21959547 Get It

Perceptions of Reimbursement for Clinical Trial Participation
Breitkopf, Carmen Radecki , Loza, Melissa, Vincent, Kathleen L. , Moench, Thomas R. , Stanberry, Lawrence R. , Rosenthal, Susan L.

Journal of Empirical Research on Human Research Ethics | September 19, 2011 | Volume: 6 | Issue: 3 | Pages: 31-38

10.1525/jer.2011.6.3.31 | PMID 21931235 Get It

A greater understanding of participant views regarding reimbursement will help investigators plan studies that have better potential for reaching target enrollment, maximize efficient recruitment, maintain scientific integrity, and enhance retention over time. As part of a clinical trial in the area of sexual health, healthy women's perceptions of reimbursement for research participation were investigated. Semi-structured, audio-recorded, qualitative interviews were conducted immediately upon women's completion of the clinical trial to enable a participant-driven understanding of perceptions about monetary reimbursement. Audio-recordings were transcribed and analyzed using framework analysis. Women (N = 30) had a mean age of 29.5 ± 5.7 years (range 22–45 years). Sixty-three percent of participants (n = 19) were non-Hispanic (white n = 13, black n = 4, and Asian n = 2), while the remaining were Hispanic (n = 11). Seventy-three percent (n = 22) reported previous participation in research. In general, women viewed reimbursement as a benefit to research participation, the amount of which should reflect time, the inconvenience to the research subject, and the potential for unknown risks in the short- and long-term. They believed reimbursement should take into account the degree of risk of the study, with investigations of experimental products offering greater reimbursement. Women believed that monetary reimbursement is unlikely to coerce an individual to volunteer for a study involving procedures or requirements that they found unacceptable. The results of this study can be used to provide guidance to those planning and evaluating reimbursement for research participation.
The utility of plasma vascular endothelial growth factor levels in the diagnosis and follow-up of patients with POEMS syndrome
D’Souza, Anita , Hayman, Suzanne R. , Mauermann, Michelle L. , Lacy, Martha Q. , Kyle, Robert A. , Kumar, Shaji , Greipp, Philip R., Lust, John A., Russell, Stephen J. , Zeldenrust, Steven R., Dingli, David , Rajkumar, S. Vincent , Dispenzieri, Angela , Buadi, Francis K. , Gertz, Morie A. , Witzig, Thomas E. , Rajkumar, S Vincent , D'Souza, Anita , Dispenzieri, Angela , Russell, Stephen J , Dingli, David , Mauermann, Michelle L

Blood | September 1, 2011 | Volume: 118 | Issue: 17 | Pages: 4663-4665

10.1182/blood-2011-06-362392 | PMID 21881050 Get It

Abstract The POEMS syndrome is associated with elevated vascular endothelial growth factor (VEGF) levels. Several studies have compared serum VEGF levels between POEMS patients and other disease entities showing higher serum VEGF in POEMS syndrome; however, it is unknown whether serum levels are reliable and reproducible given variable platelet release of VEGF. We therefore compared plasma levels of VEGF in 29 patients with POEMS syndrome with those of other disorders (n = 76). We demonstrated that plasma VEGF levels are useful in differentiating POEMS from other plasma cell dyscrasias, neuropathic processes, and multisystem illnesses. Plasma VEGF is also useful in monitoring disease activity after treatment and correlates with clinical improvements better than hematologic response.
Impact of gene expression profiling-based risk stratification in patients with myeloma receiving initial therapy with lenalidomide and dexamethasone
Kumar, Shaji , Uno, Hajime , Jacobus, Susanna , Wier, Scott A. Van, Ahmann, Greg, Henderson, Kimberly J., Haug, Jessica, Greipp, Philip R., Fonseca, Rafaël , Rajkumar, S. Vincent , Callander, Natalie S. , Siegel, David S. , Rajkumar, S Vincent , Uno, Hajime , Fonseca, Rafael

Blood | August 23, 2011 | Volume: 118 | Issue: 16 | Pages: 4359-4362

10.1182/blood-2011-03-342089 | PMID 21860025 Get It

Abstract Detection of specific chromosomal abnormalities by FISH and metaphase cytogenetics allows risk stratification in multiple myeloma; however, gene expression profiling (GEP) based signatures may enable more specific risk categorization. We examined the utility of 2 GEP-based risk stratification systems among patients undergoing initial therapy with lenalidomide in the context of a phase 3 trial. Among 45 patients studied at baseline, 7 (16%) and 10 (22%), respectively, were high-risk using the GEP70 and GEP15 signatures. The median overall survival for the GEP70 high-risk group was 19 months versus not reached for the rest (hazard ratio = 14.1). Although the medians were not reached, the GEP15 also predicted a poor outcome among the high-risk patients. The C-statistic for the GEP70, GEP15, and FISH based risk stratification systems was 0.74, 0.7, and 0.7, respectively. Here we demonstrate the prognostic value for GEP risk stratification in a group of patients primarily treated with novel agents. This trial was registered at www.clinicaltrials.gov as #NCT00098475.
Risk of Syncope in Family Members Who Are Genotype-Negative for a Family-Associated Long-QT Syndrome Mutation
Barsheshet, Alon , Moss, Arthur J. , McNitt, Scott , Polonsky, Slava, Lopes, Coeli M. , Zaręba, Wojciech , Ackerman, Michael J. , Benhorin, Jesaia, Kaufman, Elizabeth S. , Towbin, Jeffrey A. , Vincent, G. Michael, Qi, Ming , Robinson, Jennifer L. , Goldenberg, Ilan , Zareba, Wojciech

Circulation: Cardiovascular Genetics | August 11, 2011 | Volume: 4 | Issue: 5 | Pages: 491-499

10.1161/circgenetics.111.960179 | PMID 21831960 Get It

Background—Current clinical diagnosis of long-QT syndrome (LQTS) includes genetic testing of family members of mutation-positive patients. The present study was designed to assess the clinical course of individuals who are found negative for the LQTS-causing mutation in their families.Methods and Results—Multivariate Cox proportional hazards model was used to assess the risk for cardiac events (comprising syncope, aborted cardiac arrest [ACA], or sudden cardiac death [SCD]) from birth through age 40 years among 1828 subjects from the LQTS Registry who were found negative for their family LQTS-causing mutation. The median QTc of study subjects was 423 ms (interquartile range, 402–442 ms). The cumulative probability of a first syncope through age 40 years was 15%. However, only 2 patients (0.1%) had ACA, and none died suddenly during follow-up. Independent risk factors for syncope in genotype-negative subjects included female sex (hazard ratio [HR], 1.60;P=0.002), prolonged QTc (HR=1.63 per 100 ms increment,P=0.02), family history of ACA or SCD (HR=1.89,P=0.002), and LQT2 versus LQT1 family mutation (HR=1.41,P=0.03). Subgroup analysis showed that the presence of theK897Tpolymorphism in the LQT2 gene in an affected family was associated with an 11-fold (P=0.001) increase in the risk of recurrent syncope in genotype-negative subjects.Conclusions—Our findings suggest that cardiac events among genotype-negative family members of LQTS patients are dominated by nonfatal syncopal episodes without occurrence of sudden cardiac death. The risk for nonfatal events in this population may be mediated by the presence of common polymorphisms in LQTS genes.
Approach to the treatment of multiple myeloma: a clash of philosophies
Rajkumar, S. Vincent , Gahrton, Gösta , Bergsagel, P. Leif , Bergsagel, P. Leif , Rajkumar, S Vincent

Blood | July 27, 2011 | Volume: 118 | Issue: 12 | Pages: 3205-3211

10.1182/blood-2011-06-297853 | PMID 21791430 Get It

Abstract In this Perspective, we summarize some of the most contentious issues surrounding diagnosis and treatment of myeloma. We outline how a fundamental clash of philosophies, cure versus control, may be at the heart of many of the controversies. From the very definition of the disease to risk stratification to the validity of current clinical trial endpoints, we highlight the major areas of debate and provide alternative viewpoints that have implications for trial design and interpretation, as well as clinical practice.
Incidence, clinical course, and prognosis of secondary monoclonal gammopathy of undetermined significance in patients with multiple myeloma
Wadhera, Rishi K. , Kyle, Robert A. , Dispenzieri, Angela , Kumar, Shaji , Rajkumar, S. Vincent , Larson, Dirk R. , Lazarus, Hillard M. , Rajkumar, S Vincent , Dispenzieri, Angela , Wadhera, Rishi K

Blood | July 16, 2011 | Volume: 118 | Issue: 11 | Pages: 2985-2987

10.1182/blood-2011-04-349175 | PMID 21765020 Get It

Abstract During the course of multiple myeloma (MM), new monoclonal proteins of an isotype distinct from the original clone, referred to as secondary monoclonal gammopathy of undetermined significance (MGUS), have been described. We report on the frequency, characteristics, and outcome of secondary MGUS. Of the 1942 patients with MM, 128 (6.6%) developed a secondary MGUS, at a median of 12 months from the diagnosis of MM. The median duration of secondary MGUS was 5.9 months. Secondary MGUS was more common in patients after stem cell transplantation than in those who had not undergone such treatment (22.7% vs 1.6%, P < .001). Overall survival was significantly superior in MM patients who developed secondary MGUS compared with the rest of the cohort (73 vs 38 months, respectively; P < .001). The time of onset and the duration of secondary MGUS, as well as failure to resolve spontaneously, had an effect on overall survival and require further study.
Reduction in plasma cell proliferation after initial therapy in newly diagnosed multiple myeloma measures treatment response and predicts improved survival
Larsen, Jeremy T. , Lust, John A., Greipp, Philip R., Rajkumar, S. Vincent , Chee, Cheng Ean , Rajkumar, S Vincent

Blood | July 13, 2011 | Volume: 118 | Issue: 10 | Pages: 2702-2707

10.1182/blood-2011-03-341933 | PMID 21750316 Get It

AbstractStandard myeloma treatment response criteria are determined principally by changes in the monoclonal protein. Reduction in the size of the proliferative component of malignant plasma cells may be an additional metric of assessing response to therapy. We retrospectively analyzed 176 patients with newly diagnosed myeloma with a measurable plasma cell labeling index (PCLI) at diagnosis and repeat measurement 4 months after initiation of therapy. PCLI response was defined as a ≥ 60% reduction. Baseline PCLI is an independent prognostic factor; therefore, we categorized patients into 3 groups: PCLI ≥ 3% (high), ≥ 1% (intermediate), and < 1% (low). Patients achieving a greater PCLI response had improved median overall survival of 54 months compared with 29 months in nonresponders (P = .02). Improved median overall survival with PCLI response occurred in the high initial PCLI group (28 vs 7 months; P = .003) and intermediate group (64 vs 24 months; P = .002). The application of PCLI response and serum M-spike response together provided further prognostic information. On multivariate analysis, the prognostic value of PCLI response was independent of β2-microglobulin, elevated creatinine, serum M-spike response, and baseline PCLI. We conclude that a significant reduction in plasma cell proliferation in patients with newly diagnosed myeloma is an important predictor of survival.