Standardized approach for accurate and reliable model development of ion-exchange chromatography based on parameter-by-parameter method and consideration of extra-column effects.

Developing an accurate and reliable model for chromatographic separation that meets regulatory requirements and ensures consistency in model development remains challenging. In order to address this challenge, a standardized approach was proposed in this study with ion-exchange chromatography (IEC). The approach includes the following steps: liquid flow identification, system and column-specific parameters determination and validation, multi-component system identification, protein amount validation, steric mass action parameters determination and evaluation, and validation of the calibrated model's generalization ability.

DFT and microkinetic study of acetylene transformation on Pd(111), M(111) and PdM(111) surfaces (M = Cu, Ag, Au).

Density functional calculations and microkinetic simulations were performed on the transformation network of acetylene on Pd(111), M(111) and PdM(111) (M = Cu, Ag, Au) surfaces. It is demonstrated that the adsorption energies on alloy surfaces linearly correlate with the values on the pure metal surfaces. A good linear relationship between the co-adsorption energies of initial states and transition states is revealed with which the barriers of most elementary steps in the reaction network were estimated.

Effect and Safety of Therapeutic Regimens for Patients With Germline BRCA Mutation-Associated Breast Cancer: A Network Meta-Analysis.

Purpose: Breast cancer type 1 susceptibility (BRCA) mutations not only increase breast cancer (BC) risk but also result in poor survival and prognosis for BC patients. This study will analyze the effect and safety of therapeutic regimens for the treatment of BC patients with germline BRCA (gBRCA) mutations by network meta-analysis.

Methods: Public databases were searched from inception to 29 April 2021.

Suppression of phospho-p85α-GTP-Rac1 lipid raft interaction by bichalcone analog attenuates cancer cell invasion.

The p85α subunit of phosphatidylinositol 3-kinase (PI3K) acts as a key regulator of cell proliferation and motility, which mediates signals that confer chemoresistance to many human cancer cells. Using small interfering RNAs against matrix metalloproteinase-2 (MMP-2) and the MMP-2 promoter-driven luciferase assay, we showed that the new synthetic bichalcone analog TSWU-CD4 inhibits the invasion of human cancer cells by down-regulating MMP-2 expression. Treatment with TSWU-CD4 inhibited MMP-2 expression and cell invasion, which were restored by ectopic wild type (wt) p85α or a constitutively active form of MAPK kinase 3 (CA MKK3), CA MKK6, or CA p38α mitogen-activated protein kinase (MAPK).

Preparation and evaluation of dextran-grafted agarose resin for hydrophobic charge-induction chromatography.

Hydrophobic charge-induction chromatography (HCIC) is a new and effective technology for antibody separation. In the present work, HCIC resin MMI-B-XL was prepared with dextran-grafted agarose gel as the matrix and 2-mercapto-1-methyl-imidazole (MMI) as the functional ligand. The preparation procedures were optimized, and the maximum ligand density could reach as high as 200 μmol/g gel.

Development of β-amino-carbonyl compounds as androgen receptor antagonists.

Aim: Androgen receptor (AR) antagonists have proven to be useful in the early control of prostate cancer. The aim of this study was to identify and characterize a novel β-amino-carbonyl-based androgen receptor antagonist.

Methods: Different isomers of the β-amino-carbonyl compounds were obtained by chiral separation.

Evaluation of mixed-mode chromatographic resins for separating IgG from serum albumin containing feedstock.

Mixed-mode chromatography has been focused as a cost-effective new technique for antibody purification. In this study, four mixed-mode resins with N-benzyl-N-methyl ethanol amine, 2-benzamido-4-mercaptobutanoic acide, 4-mercapto-ethyl-pyridine and phenylpropylamine as the ligands were tested and the multi-functional interactions between ligand and protein were discussed. Immunoglobulin G (IgG), bovine serum albumin (BSA) and the binary mixture of BSA and IgG were used as the model feedstock to compare the separation behaviors by pH gradient elution.

Evaluation of immunoglobulin adsorption on the hydrophobic charge-induction resins with different ligand densities and pore sizes.

Hydrophobic charge-induction chromatography (HCIC) is a novel technology for antibody purification. The ligand densities and pore properties of HCIC resins have significant effects on the separation behavior of protein, however, the understandings are quite limited. In the present work, new HCIC ligand, 2-mercapto-1-methylimidazole (MMI) was coupled to three agarose matrices with different pore sizes.

Effects of ligand density and pore size on the adsorption of bovine IgG with DEAE ion-exchange resins.

Immunoglobulin G is an important plasma protein with many applications in therapeutics and diagnostics, which can be purified effectively by ion exchange chromatography. The ligand densities and pore properties of ion-exchange resins have significant effects on the separation behaviors of protein, however, the understandings are quite limited. In this work, with bovine immunoglobulin as the model IgG, the adsorption isotherms and adsorption kinetics were investigated systematically with series of diethylaminoethyl ion-exchange resins with different ligand densities and pore sizes.

Protein adsorption on DEAE ion-exchange resins with different ligand densities and pore sizes.

Ion exchange chromatography (IEC) is a common and powerful technique for the purification of proteins. The ligand density and pore properties of ion-exchange resins have significant effects on the separation behaviors of protein, however, the understandings are quite limited. In the present work, the adsorption isotherms of bovine serum albumin (BSA) and human serum albumin (HSA) were investigated systematically with series of diethylaminoethyl (DEAE) ion-exchange resins, which have different ligand densities and pore sizes.

Expression and purification of bioactive high-purity human midkine in Escherichia coli.

Midkine is a heparin-binding growth factor, which plays important roles in the regulation of cell growth and differentiation. The non-tagged recombinant human midkine (rhMK) is therefore required to facilitate its functional studies of this important growth factor. In the present work, rhMK was expressed in Escherichia coli (E.

Rhodanine derivatives as novel peroxisome proliferator-activated receptor gamma agonists.

Aim: To characterize the in vitro bioactivities of rhodanine derivatives as novel peroxisome proliferator-activated receptor (PPAR) gamma modulators, based on a hit (SH00012671) identified during high-throughput screening (HTS) of a diverse synthetic compound library, and to preliminarily elucidate the structure-activity relationship of this class of PPARgamma agonists.

Methods: Full-length PPARgamma and retinoid X receptor alpha (RXRalpha), biotinylated PPAR response element (PPRE), [3H]BRL49653 (rosiglitazone), and streptavidin-coated FlashPlate or microbeads were used to measure the receptor-binding properties of various compounds based on the scintillation proximity assay (SPA) technology. A recombinant PPRE vector was transiently cotransfected with PPARgamma and RXRalpha plasmids into the African green monkey kidney (CV-1) cells, and the effects of BRL49653 and test compounds on transcription mediated by PPARgamma were determined by examining luciferase (reporter) responses.

Inhibitory effect of Ca2+ on in vivo gene transfer by electroporation.

Aim: To investigate the specific effects of Ca2+ on transgene expression during electroporation-mediated gene transfer in mice.

Methods: Skeletal muscle and skin were subjected to in vivo electroporation with a luciferase reporter plasmid, with or without Ca2+ and various other ions.

Results: For in vivo electroporation, the presence of just 10 mmol/L Ca2+ in the DNA solution drastically reduced the resulting transgene expression, to less than 5% of control values.