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1543 citation(s) found for "Wu, Linda".

Autonomic function in gastroparesis and chronic unexplained nausea and vomiting: Relationship with etiology, gastric emptying, and symptom severity
Nguyen, Linda Anh B. , Wilson, Laura , Miriel, Laura , Pasricha, Pankaj J. , Kuo, Braden , Hasler, William L. , McCallum, Richard W. , Sarosiek, Irene , Koch, Kenneth L. , Snape, William J., Farrugia, Gianrico , Grover, Madhusudan , Clarke, John O. , Tonascia, James , Hamilton, Frank A., Rothberg, Amy E. , Nguyen, Linda A , Parkman, H P , Abell, T L , Clarke, J , Hasler, W L , Kuo, Braden , Parkman, Henry P. , Abell, Thomas L.

Neurogastroenterology & Motility | February 15, 2020 | Volume: 32 | Issue: 8 | Pages: No page available

10.1111/nmo.13810 | PMID 32061038 Get It

AbstractBackgroundAutonomic dysfunction can be present in patients with idiopathic and diabetic gastroparesis. The role of autonomic dysfunction relating to gastric emptying and upper gastrointestinal symptoms in patients with gastroparesis and chronic unexplained nausea and vomiting (CUNV) remains unclear. The aim of our study is to evaluate autonomic function in patients with gastroparesis and CUNV with respect to etiology, gastric emptying and symptom severity.MethodsWe studied 242 patients with chronic gastroparetic symptoms recruited at eight centers. All patients had a gastric emptying scintigraphy within 6 months of the study. Symptom severity was assessed using the gastroparesis cardinal symptom index. Autonomic function testing was performed at baseline enrollment using the ANX 3.0 autonomic monitoring system which measures heart rate variability and respiratory activity measurements.Key ResultsLow sympathetic response to challenge (Valsalva or standing) was the most common abnormality seen impacting 89% diabetic and 74% idiopathic patients. Diabetics compared to idiopathics, exhibited greater global hypofunction with sympathetic (OR = 4.7, 95% CI 2.2‐10.3; P < .001) and parasympathetic (OR = 7.2, 95% CI 3.4‐15.0; P < .001) dysfunction. Patients with delayed gastric emptying were more likely to have paradoxic parasympathetic excessive during sympathetic challenge [(Valsalva or standing) 40% vs. 26%, P = .05]. Patients with more severe symptoms exhibited greater parasympathetic dysfunction compared to those with mild‐moderate symptoms: resting sympathovagal balance [LFa/RFa 1.8 (1.0‐3.1) vs. 1.2 (0.6‐2.3), P = .006)] and standing parasympathetic activity [0.4 (0.1‐0.8) vs. 0.6 (0.2‐1.7); P = .03].ConclusionsAutonomic dysfunction was common in patients with gastroparesis and CUNV. Parasympathetic dysfunction was associated with delayed gastric emptying and more severe upper gastrointestinal symptoms. Conversely, sympathetic hypofunction was associated with milder symptoms.InferencesGastroparesis and CUNV may be a manifestation of GI autonomic dysfunction or imbalance, such that sympathetic dysfunction occurs early on in the manifestation of chronic upper GI symptoms, while parasympathetic dysfunction results in more severe symptoms and delayed gastric emptying.
Proof of Concept for Tipifarnib in Relapsed or Refractory Angioimmunoblastic T-Cell Lymphoma (AITL) and CXCL12+ Peripheral T-Cell Lymphoma (PTCL): Preliminary Results from an Open-Label, Phase 2 Study
Sokol, Lubomir , Kim, Won-Seog, Jacobsen, Eric D. , Cruz, Maria de Fatima De La, Caballero, Dolores, Advani, Ranjana H. , Roncero, Jose Maria, Oña, Raquel de, Izquierdo, Antonia Rodríguez, Rodríguez, Marta , Bolognese, James A., Kessler, Linda , Mishra, Vishnu S. , Curry, Robert C., Kurman, Michael R., Scholz, Catherine, Advani, Ranjana H , Witzig, Thomas E. , Sokol, Lubomir , Foss, Francine M. , Marín‐Niebla, Ana , Terol, María José , Domingo‐Doménech, Eva , Piris, Miguel Á. , Gualberto, Antonio

Blood | February 14, 2020 | Volume: 134 | Issue: Supplement_1 | Pages: 468-468

10.1182/blood-2019-128513 Get It

Background Tipifarnib is a potent and selective inhibitor of the enzyme farnesyltransferase (FT). FT catalyzes post-translational attachment of farnesyl groups required for localization of signaling molecules to the inner cell membrane. CXCL12 is a ligand for CXCR4 that is essential for T cell homing to lymphoid organs and the bone marrow, and for the maintenance of immune cell progenitors. We have previously shown that FT inhibition by tipifarnib downregulates CXCL12 secretion. Herein we report preliminary efficacy, safety and biomarker data from a Phase 2 study of tipifarnib in angioimmunoblastic T-cell lymphoma (AITL) and CXCL12+ peripheral T-cell lymphoma (PTCL) patients (pts). Methods This Phase 2 study (NCT02464228) is a multi-institutional, single-arm, open-label trial initially designed as a two-stage (11+7 pts) design to determine the efficacy, safety and biomarkers of tipifarnib in pts with relapsed/refractory (R/R) PTCL age &gt;/=18 years and a performance status of 0-2. Based on initial findings, the study was amended to include a cohort of AITL (n=12) and PTCL (n=12) pts with the CXCL12 rs2839695 A/A genotype (wt CXCL12 3'UTR cohort). Pts received tipifarnib 300 mg administered orally twice daily on days 1-21 of 28-day treatment cycles until progression of disease (PD) or unacceptable toxicity. The primary endpoint of the study is overall response rate (ORR). Tumor Whole Exon Sequencing (WES) was generated by NGS and gene expression data generated by RNA Seq. Ancillary studies also investigated the prognostic value of CXCL12 expression in pts who received standard of care treatment. Results As of 24 May 2019, 50 PTCL pts (23 AITL, 25 PTCL-NOS, 1 ALK- ALCL, 1 gamma-delta TCL) have been treated with tipifarnib, 19 pts in stages 1 and 2, and 31 pts in the ongoing AITL histology and wt CXCL12 3'UTR cohorts. Median number of prior treatment regimens was 3; 19 pts had a prior stem cell transplant. All pts (n=48 with available safety data) had at least one treatment-emergent adverse event (TEAE); 42 (88%) had at least 1 study drug-related TEAE and 13 (27%) at least 1 drug related SAE. The most frequently observed drug-related TEAEs of Grade &gt;3 occurring in 10% or more of pts were blood and lymphatic system disorders, including neutropenia (40%), thrombocytopenia (33%), leukopenia (25%), anemia and febrile neutropenia (19% each). There have been 14 deaths on study; one related to study drug (lung infection). Of 18 evaluable pts enrolled in Stages 1 and 2 of the trial, 3 partial responses (PR), 2 of them in pts with AITL histology, and 5 best responses of stable disease (SD) were observed. In the AITL cohort (11 evaluable of 16 pts enrolled), a 45% ORR and 73% clinical benefit rate (CBR; 3 CR, 2 PR and 3 SD) was observed. In the wt CXCL12 3'UTR cohort (n=12 evaluable pts), a 42% ORR was observed (3 CR, 2 PR), with 2 of the 3 CRs observed in patients of AITL histology (n=4). A total of 23 AITL subjects were enrolled in the overall study of whom 16 had WES data. A strong association with the activity of tipifarnib was observed in 8 of the 16 (50%) carrying KIR3DL2 gene variants C336R/Q386E: 50% CR rate, 75% ORR, 100% clinical benefit rate. These tumors expressed also very low levels of CXCL5, a ligand for CXCR2, that may mediate resistance to tipifarnib. High Allele Frequency of KIR3DL2 variants predicted CR to tipifarnib treatment (ROC AUC=0.94, p&lt;0.0001) and AITL patients carrying KIR3DL2 gene variants experienced a better outcome with tipifarnib treatment than with prior SOC treatment. While AITL tumors expressed high levels of CXCL12 and responded to tipifarnib, a trend for poor prognosis (22 vs 40 months median OS from diagnosis, HR=1.8, p=0.09) was observed in a series of 50 PTCL subjects treated with SOC therapy. Fifty percent of AITL and 35% of non-AITL samples overexpressed CXCL12. Conclusion The AITL and wt CXCL12 3'UTR cohorts met pre-specified statistical hypotheses supporting proof-of-concept for tipifarnib in PTCL. AITL histology, KIR3DL2 and CXCL12 genotype provided robust tools for the selection/stratification of PTCL subjects treated with tipifarnib. Extended enrollment of AITL patients continues and an update on enrollment and outcomes will be provided at the time of the presentation. Disclosures Sokol: EUSA: Consultancy. Foss:Mallinckrodt: Consultancy; Eisai: Consultancy; Spectrum: Other: fees for non-CME/CE services ; Acrotech: Consultancy; Seattle Genetics: Consultancy, Other: fees for non-CME/CE services ; miRagen: Consultancy. Kim:Donga: Research Funding; Celltrion: Research Funding; J&J: Research Funding; Roche: Research Funding; Kyowa-Kirin: Research Funding; Novartis: Research Funding; Mundipharma: Research Funding. Jacobsen:Kura Oncology: Research Funding. Advani:Kyowa Kirin Pharmaceutical Developments, Inc.: Consultancy; Kura: Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Autolus: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Research Funding; Agensys: Research Funding; Stanford University: Employment, Equity Ownership; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Celmed: Consultancy, Membership on an entity's Board of Directors or advisory committees; Forty-Seven: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cell Medica, Ltd: Consultancy; Gilead Sciences, Inc./Kite Pharma, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Infinity Pharma: Research Funding; Millennium: Research Funding. Roncero:Kura Oncology: Research Funding. Terol:Janssen: Consultancy, Research Funding; Roche: Consultancy; Gilead: Research Funding; Astra Zeneca: Consultancy; Abbvie: Consultancy. Domingo-Domenech:Bristol-Myers Squibb: Other: Travel expenses; Roche: Other: Travel expenses; Seattle Genetics: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses. Piris:Millenium/Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Lecture Fees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jansen: Membership on an entity's Board of Directors or advisory committees, Other: Lecture Fees; Nanostring: Membership on an entity's Board of Directors or advisory committees; Kyowa Kirin: Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding. Rodriguez:Kura Oncology: Research Funding. Bolognese:Kura Oncology: Consultancy. Kessler:Kura Oncology: Employment. Mishra:Kura Oncology: Employment. Curry:Kura Oncology: Employment. Kurman:Kura Oncology: Employment. Scholz:Kura Oncology: Employment, Equity Ownership, Patents & Royalties. Gualberto:Kura Oncology: Employment, Equity Ownership, Patents & Royalties.
Incorporation of Second-Tier Biomarker Testing Improves the Specificity of Newborn Screening for Mucopolysaccharidosis Type I
Peck, Dawn , Lacey, Jean M., White, Amy , Pino, Gisele , Studinski, April, Fisher, Rachel , Ahmad, Ayesha , Viall, Sarah , Shallow, Natalie, Siemon, Amy, Hamm, J. Austin, Murray, Brianna K., Jones, Kelly L. , Gavrilov, Dimitar , Oglesbee, Devin , Raymond, Kimiyo , Matern, Dietrich , Rinaldo, Piero, Tortorelli, Silvia , Price, Theodore J. , Peck, Dawn S, White, Amy L , Studinski, April L, Jones, Kelly L , Oglesbee, Devin , Price, Theodore J , Spencer, Linda J. , Murray, Brianna K.

International Journal of Neonatal Screening | February 7, 2020 | Volume: 6 | Issue: 1 | Pages: 10

10.3390/ijns6010010 | PMID 33073008 Get It

Enzyme-based newborn screening for Mucopolysaccharidosis type I (MPS I) has a high false-positive rate due to the prevalence of pseudodeficiency alleles, often resulting in unnecessary and costly follow up. The glycosaminoglycans (GAGs), dermatan sulfate (DS) and heparan sulfate (HS) are both substrates for α-l-iduronidase (IDUA). These GAGs are elevated in patients with MPS I and have been shown to be promising biomarkers for both primary and second-tier testing. Since February 2016, we have measured DS and HS in 1213 specimens submitted on infants at risk for MPS I based on newborn screening. Molecular correlation was available for 157 of the tested cases. Samples from infants with MPS I confirmed by IDUA molecular analysis all had significantly elevated levels of DS and HS compared to those with confirmed pseudodeficiency and/or heterozygosity. Analysis of our testing population and correlation with molecular results identified few discrepant outcomes and uncovered no evidence of false-negative cases. We have demonstrated that blood spot GAGs analysis accurately discriminates between patients with confirmed MPS I and false-positive cases due to pseudodeficiency or heterozygosity and increases the specificity of newborn screening for MPS I.
Stent-Only Versus Adjunctive Balloon Angioplasty Approach for Saphenous Vein Graft Percutaneous Coronary Intervention
Latif, Faisal , Uyeda, Lauren , Edson, Robert , Bhatt, Deepak L. , Goldman, Steven , Holmes, David R. , Shunk, Kendrick , Aggarwal, Kul, Bolad, Islam, Ziada, Khaled M. , McFalls, Edward O. , Irimpen, Anand, Truong, Huu Tam, Kinlay, Scott , Velagaleti, Raghava S. , Rangan, Bavana V. , Mavromatis, Kreton , Shih, Mei-Chiung , Ziada, Khaled , Bhatt, Deepak L , Rao, Sunil V. , Uretsky, Barry F. , Papademetriou, Vasilios , Banerjee, Subhash , Brilakis, Emmanouil S.

Circulation: Cardiovascular Interventions | February 5, 2020 | Volume: 13 | Issue: 2 | Pages: No page available

10.1161/circinterventions.119.008494 | PMID 32019343 Get It

Background: Direct stenting without pre-dilation or post-dilation has been advocated for saphenous vein graft percutaneous coronary intervention to decrease the incidence of distal embolization, periprocedural myocardial infarction, and target lesion revascularization. Methods: We performed a post hoc analysis of patients enrolled in the DIVA (Drug-Eluting Stents Versus Bare Metal Stents in Saphenous Vein Graft Angioplasty; NCT 01121224) prospective, double-blind, randomized controlled trial. Patients were stratified into stent-only and balloon-stent groups. Primary end point was 12-month incidence of target vessel failure (defined as the composite of cardiac death, target vessel myocardial infarction, or target vessel revascularization). Secondary end points included all-cause death, stent thrombosis, myocardial infarction, and target lesion revascularization during follow-up. Results: Of the 575 patients included in this substudy, 185 (32%) patients underwent stent-only percutaneous coronary intervention. Patients in the stent-only versus balloon-stent group had similar baseline characteristics and similar incidence of target vessel failure at 12-months (15% versus 19%; hazard ratio, 1.34 [95% CI, 0.86–2.08]; P =0.19). During long-term follow-up (median of 2.7 years), the incidence of definite stent thrombosis (1% versus 5%; hazard ratio, 9.20 [95% CI, 1.23–68.92]; P =0.0085), the composite of definite or probable stent thrombosis (5% versus 11%; hazard ratio, 2.52 [95% CI, 1.23–5.18]; P =0.009), and target vessel myocardial infarction (8% versus 14%; hazard ratio, 1.92 [95% CI, 1.08–3.40]; P =0.023) was lower in the stent-only group. Multivariable analysis showed that a higher number of years since coronary artery bypass grafting and >1 target saphenous vein graft lesions were associated with increased target vessel failure during entire follow-up, while preintervention Thrombolysis in Myocardial Infarction-3 flow was protective. Conclusions: In patients undergoing percutaneous coronary intervention of de novo saphenous vein graft lesions, there was no difference in target vessel failure at 12 months and long-term follow-up in the stent-only versus the balloon-stent group; however, the incidence of stent thrombosis was lower in the stent-only group, as was target vessel myocardial infarction. Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT 01121224.
Development and Validation of a Next-Generation Sequencing Panel for Syndromic and Nonsyndromic Hearing Loss
Butz, Malinda L., McDonald, Amber , Lundquist, Patrick A. , Meyer, Mélanie, Harrington, Sean C., Kester, Sarah, Stein, Mariam I. , Mistry, Nipun A., Zuckerman, Eric Zimmerman , Schimmenti, Lisa A. , Hasadsri, Linda , Boczek, Nicole J. , Butz, Malinda, Harrington, Sean, Zimmerman Zuckerman, Eric, Schimmenti, Lisa, Schimmenti, Lisa A , Niu, Zhiyv

The Journal of Applied Laboratory Medicine | February 3, 2020 | Volume: 5 | Issue: 3 | Pages: 467-479

10.1093/jalm/jfaa021 | PMID 32445360 Get It

Abstract Background Deafness and hearing loss are common conditions that can be seen independently or as part of a syndrome and are often mediated by genetic causes. We sought to develop and validate a hereditary hearing loss panel (HHLP) to detect single nucleotide variants (SNVs), insertions and deletions (indels), and copy number variants (CNVs) in 166 genes related to nonsyndromic and syndromic hearing loss. Methods We developed a custom-capture next-generation sequencing (NGS) reagent to detect all coding regions, ±10 flanking bp, for the 166 genes related to nonsyndromic and syndromic hearing loss. Our validation consisted of testing 52 samples to establish accuracy, reproducibility, and analytical sensitivity. In addition to NGS, supplementary methods, including multiplex ligation-dependent probe amplification, long-range PCR, and Sanger sequencing, were used to ensure coverage of regions that had high complexity or homology. Results We observed 100% positive and negative percentage agreement for detection of SNVs (n = 362), small indels (1–22 bp, n = 25), and CNVs (gains, n = 8; losses, n = 17). Finally, we showed that this assay was able to detect variants with a variant allele frequency ≥20% for SNVs and indels and ≥30% to 35% for CNVs. Conclusions We validated an HHLP that detects SNVs, indels, and CNVs in 166 genes related to syndromic and nonsyndromic hearing loss. The results of this assay can be utilized to confirm a diagnosis of hearing loss and related syndromic disorders associated with known causal genes.
Development and Evaluation of a Cancer Literacy Intervention to Promote Mammography Screening Among Navajo Women: A Pilot Study
Sinicrope, Pamela S. , Bauer, Mark , Austin-Garrison, Martha A., Garcia, Linda, Hughes, Christine A. , Bock, Martha J. , Decker, Paul A. , Yost, Kathleen J. , Petersen, Wesley O., Buki, Lydia P. , Garrison, Edward R., Patten, Christi A. , Sinicrope, Pamela , Decker, Paul A.

American Journal of Health Promotion | January 27, 2020 | Volume: 34 | Issue: 6 | Pages: 681-685

10.1177/0890117119900592 | PMID 31986899 Get It

Purpose: Develop and evaluate a mammography intervention that provides hope about cancer prevention and treatment. Design: Pilot randomized controlled trial. Setting: Two communities on the Navajo Nation. Participants: Navajo women and support persons. Intervention: Both groups received standard care: one home visit discussing mammography pros/cons and barriers. The treatment group received an intervention based on Navajo language via an additional home visit with health education materials (written and oral) in English and Navajo, including a Navajo Cancer Glossary with a new descriptive phrase for cancer. Analysis: Between control and intervention conditions, we compared baseline sociodemographics; changes from baseline to 3 months on mammography completion and breast cancer literacy scores. Measures: (1) intervention feasibility; (2) self- and clinic-reported mammography screening completion; (3) breast cancer literacy. Results: A total of 25 participants were randomly assigned (13 treatment, 12 control), with 7 support persons in each arm. Mean age was 53 years, 90% had a high school degree or higher, 86% spoke Navajo and English. At 3 months, 44% had a clinically verified mammogram. Mammography completion was 57% among those with a support person and 27% among those without ( P = .14). Intervention women reported more breast cancer beliefs consistent with mammography ( P = .015). Conclusions: Increases in breast cancer beliefs consistent with mammography show promise. Findings highlight a need to tailor education materials to Navajo culture/language and focus on enhancing support.
Trimolecular Complexes of λ Light Chain Dimers in Serum of a Patient with Multiple Myeloma
Abraham, Roshini S. , Charlesworth, M. Cristine , Owen, Barbara, Benson, Linda M., Katzmann, Jerry A., Reeder, Craig B. , Kyle, Robert A. , Charlesworth, M. Cristine , Owen, Barbara AL

Clinical Chemistry | January 24, 2020 | Volume: 48 | Issue: 10 | Pages: 1805-1811

10.1093/clinchem/48.10.1805 Get It

AbstractBackground: Patients with multiple myeloma often have Bence Jones proteins composed of free monoclonal light chains of the κ or λ type in their urine. Usually, these light chains exist as monomeric or dimeric forms, but rarely, larger molecules, such as tetramers, have been reported in the serum.Methods and Results: We report the presence of trimeric complexes of λ light chain dimers in a patient who was diagnosed with a free λ light chain multiple myeloma 2 years earlier and subsequently underwent a stem cell transplant. Recently, the patient presented with a large serum M-spike (23 g/L) by protein electrophoresis. The spike consisted of monoclonal λ light chains without a heavy chain. The urine contained only 8 mg of λ light chain in a 24-h specimen. Quantitative analysis of the serum and urinary free light chains (FLCs) indicated the probability of larger aggregates of FLCs. Size-exclusion chromatography, electrophoresis, analytical ultracentrifugation, and mass spectrometric studies of the serum revealed almost exclusively the presence of trimolecular aggregates of λ light chain dimers without other multimeric species.Conclusion: Monoclonal λ light chains may present as hexameric aggregates that cannot be cleared by renal excretion.
Quantitative Measurement of Porphobilinogen in Urine by Stable-Isotope Dilution Liquid Chromatography-Tandem Mass Spectrometry
Ford, Roddey E., Magera, Mark J , Kloke, Karen M., Chezick, Paul A., Fauq, Abdul H. , McConnell, Joseph P.

Clinical Chemistry | January 23, 2020 | Volume: 47 | Issue: 9 | Pages: 1627-1632

10.1093/clinchem/47.9.1627 Get It

AbstractBackground: Measurement of porphobilinogen (PBG) is useful in the diagnosis of the acute neurologic porphyrias. Currently used colorimetric assays lack analytical and clinical sensitivity and specificity.Methods: We developed a liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) method for the measurement of PBG in 1 mL of urine, using 5-(aminoethyl)-4-(carboxymethyl) 1H-2,4-[13C]pyrolle-3-propanoic acid ([2,4-13C]PBG; 2.75 μg) as internal standard. After solid-phase extraction, LC-MS/MS analysis was performed in the selected-reaction monitoring (SRM) mode. PBG and [2,4-13C]PBG were monitored through their own precursor and product ion settings (m/z 227 to 210 and m/z 229 to 212, respectively). The retention time of PBG and [2,4-13C]PBG was 1.0 min in a 2.3-min analysis.Results: Daily calibrations (n = 6) between 0.1 and 2.0 mg/L were linear and reproducible. Inter- and intraassay CVs were 3.2–3.5% and 2.6–3.1%, respectively, at mean concentrations of 0.24, 1.18, and 2.15 mg/L. The regression equation for the comparison between an anion-exchange column method (y) and the LC-MS/MS method (x) was: y = 0.84x + 0.74 (Sy|x = 5.8 mg/24 h; r = 0.85; n = 100). In 47 volunteers, PBG excretion was 0.02–0.42 mg/24 h, lower than reported reference intervals (up to 2.0 mg/24 h) based on colorimetric methods. In 85 samples with PBG ≤0.5 by LC-MS/MS, 8 (9.4%) had values ≥2.0 mg/24 h by the anion-exchange method (mean ± SD, 4.3 ± 1.8 mg/24 h). In 11 patients with confirmed diagnoses of acute porphyria and increased PBG by LC-MS/MS, 2 had values within the reported reference intervals by a quantitative anion-exchange method.Conclusions: The quantitative LC-MS/MS method for PBG measurement exhibits greater analytical specificity and improved clinical sensitivity and specificity than currently available methods.
Development of a Rapid, Quantitative Method for LDL Subfractionation with Use of the Quantimetrix Lipoprint LDL System
Hoefner, Daniel M , Hodel, Shannon D, Branum, Earl L., Sun, Deborah H., Meissner, Irene, McConnell, Joseph P., O’Brien, John F.

Clinical Chemistry | January 23, 2020 | Volume: 47 | Issue: 2 | Pages: 266-274

10.1093/clinchem/47.2.266 Get It

Abstract Background: Recent evidence suggests that the presence of small, dense LDL is independently associated with increased risk of developing coronary artery disease. Current methods to subfractionate LDL are time-consuming and/or technically demanding. Therefore, we have sought the development of a less complex LDL subfractionation procedure. Methods: LDL subfractions were separated using the Quantimetrix LipoprintTM LDL System. High-resolution 3% polyacrylamide gel tubes were scanned densitometrically (610 nm) with a Helena EDC system. A computerized method to identify and quantitatively score the resolved LDL subfractions was developed. Results from the Quantimetrix method were compared using 51 plasma samples with values obtained by nondenaturing gradient gel electrophoresis (NDGGE) and nuclear magnetic resonance (NMR) spectroscopy. Results: LDL subfractionation scores correlated significantly (P &lt;0.05) with triglyceride, HDL-cholesterol, apolipoprotein B100, and LDL-cholesterol/apolipoprotein B100 (r = 0.591, −0.392, 0.454, and −0.411, respectively). For 51 samples, the Quantimetrix method classified 21 with small, 14 with intermediate, and 16 with large LDL. Of the 21 samples classified as small by Quantimetrix, 20 (95%) were classified as small (n = 18) or intermediate (n = 2) by NDGGE. All of the 16 specimens classified as large by Quantimetrix were either large (n = 14) or intermediate (n = 2) by NDGGE. LDL score was inversely correlated (r = −0.674; P &lt;0.0001) with LDL particle size determined by NMR spectroscopy. Conclusions: A quantitative method for the assessment of LDL particle size phenotype was developed using the Quantimetrix Lipoprint LDL System. The method can be performed in less than 3 h in batch mode and is suitable for routine use in clinical laboratories.