Unification of de novo and acquired ibrutinib resistance in mantle cell lymphoma.

The novel Bruton's tyrosine kinase inhibitor ibrutinib has demonstrated high response rates in B-cell lymphomas; however, a growing number of ibrutinib-treated patients relapse with resistance and fulminant progression. Using chemical proteomics and an organotypic cell-based drug screening assay, we determine the functional role of the tumour microenvironment (TME) in ibrutinib activity and acquired ibrutinib resistance. We demonstrate that MCL cells develop ibrutinib resistance through evolutionary processes driven by dynamic feedback between MCL cells and TME, leading to kinome adaptive reprogramming, bypassing the effect of ibrutinib and reciprocal activation of PI3K-AKT-mTOR and integrin-β1 signalling.

An Platform for the Prediction of Clinical Response in Multiple Myeloma.

Multiple myeloma remains treatable but incurable. Despite a growing armamentarium of effective agents, choice of therapy, especially in relapse, still relies almost exclusively on clinical acumen. We have developed a system, Mathematical Myeloma Advisor (EMMA), consisting of patient-specific mathematical models parameterized by an assay that reverse engineers the intensity and heterogeneity of chemosensitivity of primary cells from multiple myeloma patients, allowing us to predict clinical response to up to 31 drugs within 5 days after bone marrow biopsy.

An Organotypic High Throughput System for Characterization of Drug Sensitivity of Primary Multiple Myeloma Cells.

In this work we describe a novel approach that combines ex vivo drug sensitivity assays and digital image analysis to estimate chemosensitivity and heterogeneity of patient-derived multiple myeloma (MM) cells. This approach consists in seeding primary MM cells freshly extracted from bone marrow aspirates into microfluidic chambers implemented in multi-well plates, each consisting of a reconstruction of the bone marrow microenvironment, including extracellular matrix (collagen or basement membrane matrix) and stroma (patient-derived mesenchymal stem cells) or human-derived endothelial cells (HUVECs). The chambers are drugged with different agents and concentrations, and are imaged sequentially for 96 hr through bright field microscopy, in a motorized microscope equipped with a digital camera.

Binding of Yeast Cytochrome c to Forty-Four Charge-Reversal Mutants of Yeast Cytochrome c Peroxidase: Isothermal Titration Calorimetry.

Previously, we constructed, expressed, and purified 46 charge-reversal mutants of yeast cytochrome c peroxidase (CcP) and determined their electronic absorption spectra, their reaction with H2O2, and their steady-state catalytic properties [ Pearl , N. M. et al.

Handheld ultrasound versus physical examination in patients referred for transthoracic echocardiography for a suspected cardiac condition.

Objectives: The purpose of this study was to test the hypothesis that handheld ultrasound (HHU) provides a more accurate diagnosis than physical examination in patients with suspected cardiovascular abnormalities and that its use thus reduces additional testing and overall costs.

Background: Despite the limitations of physical examination and the demonstrated superiority of HHU for detecting cardiac abnormalities, it is not routinely used for the bedside diagnosis of cardiac conditions.

Methods: Patients referred for a standard echocardiogram for common indications (cardiac function, murmur, stroke, arrhythmias, and miscellaneous) underwent physical examination and HHU by different cardiologists, who filled out a form that also included suggestions for additional testing, if necessary, based on their findings.

A preclinical assay for chemosensitivity in multiple myeloma.

Accurate preclinical predictions of the clinical efficacy of experimental cancer drugs are highly desired but often haphazard. Such predictions might be improved by incorporating elements of the tumor microenvironment in preclinical models by providing a more physiological setting. In generating improved xenograft models, it is generally accepted that the use of primary tumors from patients are preferable to clonal tumor cell lines.

Comparison of left and right atrial volume by echocardiography versus cardiac magnetic resonance imaging using the area-length method.

Increased atrial volumes predict adverse cardiovascular events. Accordingly, accurate measurement of atrial size has become increasingly important in clinical practice. The area-length method is commonly used to estimate the volume.

Effect of single-site charge-reversal mutations on the catalytic properties of yeast cytochrome c peroxidase: evidence for a single, catalytically active, cytochrome c binding domain.

Forty-six charge-reversal mutants of yeast cytochrome c peroxidase (CcP) have been constructed in order to determine the effect of localized charge on the catalytic properties of the enzyme. The mutants include the conversion of all 20 glutamate residues and 24 of the 25 aspartate residues in CcP, one at a time, to lysine residues. In addition, two positive-to-negative charge-reversal mutants, R31E and K149D, are included in the study.

Effect of single-site charge-reversal mutations on the catalytic properties of yeast cytochrome c peroxidase: mutations near the high-affinity cytochrome c binding site.

Fifteen single-site charge-reversal mutations of yeast cytochrome c peroxidase (CcP) have been constructed to determine the effect of localized charge on the catalytic properties of the enzyme. The mutations are located on the front face of CcP, near the cytochrome c binding site identified in the crystallographic structure of the yeast cytochrome c-CcP complex [Pelletier, H., and Kraut, J.

Azide binding to yeast cytochrome c peroxidase and horse metmyoglobin: comparative thermodynamic investigation using isothermal titration calorimetry.

Yeast cytochrome c peroxidase (CcP) and horse metmyoglobin (Mb) bind HN3 with similar affinities at 25 degrees C. The pH-independent equilibrium association constants for formation of the CcP.HN3 and Mb.

Muscle activation patterns in subjects with and without low back pain.

Objective: To analyze muscle activation patterns during various footplate perturbations, used as proprioceptive challenges in patients with low back pain (LBP) and in controls.

Design: A prospective and controlled comparative study.

Setting: Outpatient clinic.