Influence of Arginine Salts on the Thermal Stability and Aggregation Kinetics of Monoclonal Antibody: Dominant Role of Anions

Thermal stability of the C_H2 domain for an IgG1 monoclonal antibody and its aggregation kinetics were systematically studied at pH 4.8, below its pI of 8.8 in individual solutions of arginine salts with acetate, glutamate (Glu^–), chloride, and sulfate as the anion, in comparison to sodium chloride and sodium sulfate. Thermal unfolding temperature, <i>T</i>_m, an indicator of thermal stability, was measured by both differential scanning calorimetry (DSC) and differential scanning fluorimetry (DSF). The aggregation kinetics was determined by assessing reversibility for the C_H2 domain in the DSC repetitive scans and then cross-examined by the isothermal aggregation study measured by size exclusion chromatography. The effect of Arg⁺ on the thermal stability and aggregation kinetics of the antibody is shown to be strongly anion-dependent: both ArgAceate and ArgGlu improve the stability, while both Arg₂SO₄ and ArgCl decrease it. Furthermore, the addition of ArgCl and Arg₂SO₄ accelerates the aggregation kinetic, but to a lesser extent than the respective Na⁺ salt, suggesting that Arg⁺ binds to the antibody more strongly than Na⁺. However, the binding of Arg⁺ did not lead to more destabilization of the C_H2 domain by the Arg⁺ salts at low concentrations, comparing to the respective Na⁺ salt. This finding indicates that Arg⁺ prefers the protein surface, rather than the exposed backbone upon unfolding. Furthermore, the change in the ranking for affecting the thermal stability and aggregation kinetics as the salt concentration increases implies the presence of other multiple mechanisms, e.g., cluster formation through the homoion pairing between Arg⁺ molecules and their preferential exclusion from the protein surface, and heteroion pairing between Arg⁺ and SO₄^2–

The Effects of Traditional Chinese Exercise in Patients with Chronic Obstructive Pulmonary Disease: A Meta-Analysis

<div><p>Background</p><p>Chronic obstructive pulmonary disease (COPD) is a major public health problem worldwide. However, several studies that have assessed the role of traditional Chinese exercise in the management of this disease include broad variations in sample sizes and results. Therefore, this meta-analysis was conducted to assess the effects of traditional Chinese exercise on patients with COPD.</p><p>Methods</p><p>Two investigators independently identified and extracted data from selected articles. A computerized search of electronic databases through August 2015 was conducted. Mean differences (MDs) and 95% confidence intervals (CIs) were calculated to analyze the combined data. The methodological quality was evaluated using the Cochrane risk-of-bias tool. Heterogeneity was assessed with the I² test.</p><p>Results</p><p>Ten randomized, controlled trials (RCTs) involving 622 patients met the inclusion criteria. There were significant improvements in the 6-minute walking distance test (6 MWD;MWD = 12.10 m; 95% CI, 7.56–16.65 m; p<0.001); forced expiratory volume in one second (FEV1% predicted; WMD = 9.02; 95% CI, 6.80–11.23; p<0.00001); forced expiratory volume in 1 second/forced vital capacity (FEV(1)/FVC) ratio (Tiffenau Index; WMD = 6.67; 95% CI, 5.09–8.24; p<0.00001); and quality of life, as evaluated by the Chronic Respiratory Disease Questionnaire (CRDQ; WMD = 0.85 score; 95% CI, 0.52–1.18; p<0.00001).</p><p>Conclusions</p><p>Traditional Chinese exercise could provide an effective alternative method for managing COPD. Larger and higher-quality trials are required.</p></div

Effects of traditional Chinese exercise on health-related quality of life.

<p><b>A meta-analysis of RCTs evaluating the effects of traditional Chinese exercise on health-related quality of life using a fixed effects model.</b></p

Characteristics of the randomized controlled trials included in the meta-analysis.

<p>Characteristics of the randomized controlled trials included in the meta-analysis.</p

Generation of cardiomyocyte-specific FABP4 transgenic mice.

<p>(A) Schematics of mouse α-MHC-driven FABP4 transgenic construct, HGH-PA: human growth hormone polyadenylation signal. (B) The expression of FABP4 in isolated adult cardiomyocytes from wild type and FABP4-TG mice. Relative expression levels of FABP4 protein normalized by GAPDH are expressed as mean±SD (n = 6, **p<0.01) and shown in the right panel. (C) qRT-PCR was used to measure gene expression levels in hearts. (mean±SD, n = 8).</p

Search strategy and flow chart of the screened, excluded and analyzed articles.

<p>Search strategy and flow chart of the screened, excluded and analyzed articles.</p

Egr-1 binding sites are essential for Rad promoter activation.

<p>(A) Nucleotide sequence between base pairs -76 and -51bp of Rad promoter. Egr-1 binding sites are boxed. The mutated bases are indicated in boldface. (B) Wild-type and mutant forms of pRad-155 were cotransfected with pcDNA3.1-Egr-1* or pcDNA3.1 into 293A cells and luciferase activity were determined. The fold induction of Lucifearse activity by Egr-1 was shown in the lower panel; (C) RASMCs were transfected with pRad-155 promoter reporter or its mutant forms then treated with PDGF and luciferase activity were determined (n = 4, **<i>p</i><0.01). (D) pRad-3050 and pRad-3050m were transfected into RASMCs then treated with PDGF and luciferase activity were determined (n = 4, **<i>p</i><0.01).</p

Sensitivity analyses of the 6 MWD and Tiffenau index, excluding low-quality trials.

<p>Sensitivity analyses of the 6 MWD and Tiffenau index, excluding low-quality trials.</p

Effects of traditional Chinese exercise on 6-minute walking distance.

<p>The subgroup meta-analysis of RCTs evaluating the effects of traditional Chinese exercise on the 6 MWD using a fixed effects model.</p

Egr-1 binds to Rad promoter after PDGF treatment.

<p>ChIP assay was performed in RASMC stimulated with or without PDGF (20 ng/ml) for 1 hour. After formaldehyde cross-linking, the protein-DNA complexes were recovered using anti-Egr-1 antibody or non-specific IgG. PCR was performed to detect the proximal Rad promoter. PCR products were detected by 2% agarose gel electrophoresis.</p