Overcoming Drug Interference in Transfusion Testing: A Spotlight on Daratumumab

Overexpression in insect cells of the full coding sequence of the human membrane cytoskeletal linker ezrin (1-586) was compared with that of a NH2-terminal domain (ezrin 1-233) and that of a COOH-terminal domain (ezrin 310-586). Ezrin (1-586), as well as ezrin (1-233) enhanced cell adhesion of infected Sf9 cells without inducing gross morphological changes in the cell structure. Ezrin (310-586) enhanced cell adhesion and elicited membrane spreading followed by microspike and lamellipodia extensions by mobilization of Sf9 cell actin. Moreover some microspikes elongated into thin processes, up to 200 microns in length, resembling neurite outgrowths by a mechanism requiring microtubule assembly. Kinetics of videomicroscopic and drug-interference studies demonstrated that mobilization of actin was required for tubulin assembly to proceed. A similar phenotype was observed in CHO cells when a comparable ezrin domain was transiently overexpressed. The shortest domain promoting cell extension was localized between residues 373-586. Removal of residues 566-586, involved in in vitro actin binding (Turunen, O., T. Wahlström, and A. Vaheri. 1994. J. Cell Biol. 126:1445-1453), suppressed the extension activity. Coexpression of ezrin (1-233) with ezrin (310-586) in the same insect cells blocked the constitutive activity of ezrin COOH-terminal domain. The inhibitory activity was mapped within ezrin 115 first NH2-terminal residues. We conclude that ezrin has properties to promote cell adhesion, and that ezrin NH2-terminal domain negatively regulates membrane spreading and elongation properties of ezrin COOH-terminal domain.

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Real-time monitoring of immune responses under pathogen invasion and drug interference by integrated microfluidic device coupled with worm-based biosensor

Biosensors and Bioelectronics ◽

10.1016/j.bios.2018.03.058 ◽

2018 ◽

Vol 110 ◽

pp. 233-238 ◽

Cited By ~ 10

Author(s):

Liang Hu ◽

Anle Ge ◽

Xixian Wang ◽

Shanshan Wang ◽

Xinpei Yue ◽

...

Keyword(s):

Immune Responses ◽

Real Time ◽

Microfluidic Device ◽

Real Time Monitoring ◽

Drug Interference ◽

Pathogen Invasion

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Abstract P612: The AA2-Ratio: Towards Improved Screening for Primary Aldosteronism

Hypertension ◽

10.1161/hyp.68.suppl_1.p612 ◽

2016 ◽

Vol 68 (suppl_1) ◽

Author(s):

Marko Poglitsch ◽

Ashraf H Ahmed ◽

Andrea Stoller ◽

Dunja van Oyen ◽

Oliver Domenig ◽

...

Keyword(s):

Angiotensin Ii ◽

Primary Aldosteronism ◽

Ace Inhibitor ◽

False Negative ◽

Renin Angiotensin System ◽

Ace Inhibition ◽

Serum Samples ◽

Drug Interference ◽

Salt Loading ◽

Hypertensive Patients

Background: Primary aldosteronism (PA) is a widely under-diagnosed, potentially curable and specifically treatable cause of hypertension. PA screening involves measuring the aldosterone-to-renin-ratio (ARR), but false negative results can occur in the setting of medications, which block the renin-angiotensin system (RAS). Withdrawing RAS blockers from patients with resistant hypertension is not without cardiovascular risk. A novel diagnostic approach, the aldosterone-to-angiotensin-II-ratio (AA2-Ratio), has the potential for less drug interference and improved reliability in PA screening and confirmation of diagnosis. Methods: Serum samples from 80 patients undergoing PA confirmation testing were analyzed. Sampling was performed in a recumbent (7 a.m.) and in an upright (10 a.m.) position before and after 4 days of oral administration of fludrocortisone and salt loading. The concentrations of renin, aldosterone and equilibrium Angiotensin-II were determined and ARR and AA2-Ratios were calculated. The interference of ACE-inhibition with the AA2-Ratio was investigated in healthy volunteers receiving 10mg enalapril daily for 8 days. Results: Renin concentration was undetectable in more than 40% of samples, while equilibrium Angiotensin-II was measurable in 98% of all 320 samples analyzed. Angiotensin-II levels were significantly higher in upright collected samples compared to samples collected in a recumbent position. Comparison of the ARR with the AA2-Ratio revealed a significantly larger diagnostic window for the AA2-Ratio. While the ARR was significantly suppressed by ACE-inhibitor treatment, the AA2-Ratio remained unaffected by ACE-inhibition. Conclusion: The AA2-Ratio may be superior to the ARR in PA screening among hypertensive patients. Equilibrium Angiotensin-II levels show expected responses to posture and appear to outperform renin concentration as a marker for RAS activation in terms of sensitivity, giving a measurable readout even in clinical states characterized by markedly suppressed RAS activity. The stability of the AA2-Ratio in the presence of ACE-inhibition points to a potential use of the AA2-Ratio PA screening in hypertensive patients without ACE-inhibitor discontinuation.

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Immunogenicity of Golimumab and its Clinical Relevance in Patients With Ulcerative Colitis

Inflammatory Bowel Diseases ◽

10.1093/ibd/izz003 ◽

2019 ◽

Vol 25 (9) ◽

pp. 1532-1540 ◽

Cited By ~ 8

Author(s):

Omoniyi J Adedokun ◽

George R Gunn ◽

Jocelyn H Leu ◽

Cynthia Gargano ◽

Zhenhua Xu ◽

...

Keyword(s):

Ulcerative Colitis ◽

False Negative ◽

Injection Site Reaction ◽

High Sensitivity ◽

Fold Increase ◽

Drug Interference ◽

Negative Results ◽

Drug Concentrations ◽

Antidrug Antibody ◽

Antibody Titers

Abstract Background Antidrug antibody (ADA) detection with standard bridging enzyme immunoassays (EIA) can yield false-negative results or underestimate titers through drug interference. A more sensitive assay was needed to determine clinical impact of antigolimumab antibodies. Methods A high-sensitivity, drug-tolerant EIA (DT-EIA) was developed and cross-validated against the original EIA, and samples from induction/maintenance studies in golimumab-treated patients with ulcerative colitis were analyzed for ADAs using both methods. Immunogenicity results were compared, and pharmacokinetic, efficacy, and safety associations were evaluated. Results An 8-fold increase in ADA-positive patients (21.8% DT-EIA vs 2.8% EIA) reflected DT-EIA improved sensitivity and drug tolerance. Most newly detected ADA-positive patients (using DT-EIA) had low antibody titers, whereas most with high antibody titers were ADA-positive with original EIA. With DT-EIA, week 44 median trough serum golimumab concentrations among ADA-positive patients were approximately half vs ADA-negative (0.51 vs 0.85 µg/mL [50 mg q4w]; 0.85 vs 1.60 µg/mL [100 mg q4w]). Antidrug antibody impact on golimumab concentrations was more notable at titers ≥1:100. During induction, ADAs had no notable impact on efficacy. During maintenance, proportions of patients maintaining clinical response through week 54 were lower using DT-EIA: 38.1% ADA-positive and 52.8% ADA-negative. Antidrug antibody status had no impact on injection-site reaction incidence. Conclusions A more sensitive DT-EIA identified higher proportions of ADA-positive patients. A trend of decreasing drug concentrations with increasing ADA titers was observed. Pharmacokinetic impact was better elucidated with DT-EIA. Although development of ADA did not preclude efficacy, a trend toward decreased efficacy in ADA-positive vs ADA-negative patients was observed during maintenance treatment. Antidrug antibody status did not impact safety.

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Lithium determinations evaluated in eight analyzers

Clinical Chemistry ◽

10.1093/clinchem/40.6.869 ◽

1994 ◽

Vol 40 (6) ◽

pp. 869-872 ◽

Cited By ~ 20

Author(s):

M Sampson ◽

M Ruddel ◽

R J Elin

Keyword(s):

Colorimetric Method ◽

Atomic Emission ◽

Ion Selective Electrodes ◽

Drug Interference ◽

Flame Atomic Absorption ◽

Analytical Recovery ◽

And Performance ◽

Mean Differences ◽

Sodium And Potassium

Abstract We compared five ion-selective electrodes (ISEs; AVL 985S, Baxter Lytening 2Z, Beckman EL-ISE, Ciba-Corning 654 Na/K/Li, and Nova CRT 11) and a colorimetric method (Ektachem) for determination of lithium with flame atomic absorption and atomic emission spectroscopy. We evaluated precision, recovery, interference by drugs (procainamide, N-acetylprocainamide, quinidine, lidocaine, carbamazepine, and valproic acid) and inorganic analytes (Na, K, Ca, Mg, and Br), and performance with sera from patients receiving lithium. Imprecision was < 5% (CV) for all analyzers except Ektachem and Beckman. Analytical recovery was 100% +/- 5% for all analyzers except Ektachem and Baxter. Some drug interference was seen with all analyzers except AVL and Corning. Calcium caused interference with AVL, Corning, and Ektachem analyzers, and sodium and potassium interfered with the Ektachem analyzer. The results with the Baxter, Beckman, and Corning analyzers were closest to those by flame atomic emission (mean differences, 0.01 to 0.02 mmol/L); the AVL and Nova analyzers gave lower results (mean differences, -0.11 to -0.13 mmol/L) and the Ektachem gave higher results (mean difference, 0.08 mmol/L).

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