Purification and characterization of chimeric human IgA1 and IgA2 expressed in COS and Chinese hamster ovary cells

Ag-specific chimeric human IgA molecules, of the two human subclasses, IgA1 and IgA2, have been expressed in two mammalian cell systems. Analysis of the secreted IgA molecules, purified in milligram quantities from stable Chinese hamster ovary transfectants by Ag affinity chromatography, has allowed a direct comparison of the biologic properties of the two subclasses. HPLC gel filtration analysis revealed that in both subclasses, the IgA molecules associate predominantly into dimers. The monomer units are presumed to interact noncovalently, inasmuch as no dimers are evident when the antibodies are subjected to SDS-PAGE. The recombinant antibodies are glycosylated, inasmuch as a lectin blotting procedure revealed that the H chains of both subclasses are recognized by Con A. When subjected to digestion by preparations of IgA1-specific proteases secreted by two pathogenic streptococcal strains, Streptococcus sanguis and Streptococcus oralis, the recombinant IgA molecules behave just as their natural equivalents. Thus, only the chimeric IgA1 molecule is cleaved, with the IgA2 remaining intact. In terms of interaction with natural effector molecules, both recombinant IgA isotypes were shown to interact with Fc alpha receptors on calcitriol-stimulated HL-60 cells with similar affinity, but neither antibody was found to interact with human C1q. The expression system described readily permits manipulation of the human IgA genes, which should lead to a fuller molecular understanding of how this important antibody mediates its function.     

Cylindrical standing surface waves in superfluid helium

A theoretical analysis is given of the resonant frequencies of standing surface waves produced in a cylinder filled with superfluid⁴He. In particular, it is shown that a heat transfer coefficient involved in a recently proposed empirical boundary condition can be related to the Kapitza resistance.     

Lipid-modifying activity of curcuminoids: A systematic review and meta-analysis of randomized controlled trials

Objective: The aim of this systematic review and meta-analysis was to determine and clarify the impact of curcuminoids on serum lipid levels. Methods: Randomized controlled trials (RCTs) investigating the effects of curcuminoids on plasma lipids were searched in PubMed-Medline, Scopus, Web of Science databases (from inception to April 3^rd, 2017). A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on lipid concentrations. Results: A meta-analysis of 20 RCTs with 1427 participants suggested a significant decrease in plasma concentrations of triglycerides (WMD: ?21.36 mg/dL, 95% CI: ?32.18, ?10.53, p < 0.001), and an elevation in plasma HDL-C levels (WMD: 1.42 mg/dL, 95% CI: 0.03, 2.81, p = 0.046), while plasma levels of LDL-C (WMD: ?5.82 mg/dL, 95% CI: ?15.80, 4.16, p = 0.253) and total cholesterol (WMD: ?9.57 mg/dL, 95% CI: ?20.89, 1.75, p = 0.098) were not altered. The effects of curcuminoids on lipids were not found to be dependent on the duration of supplementation. Conclusion: This meta-analysis has shown that curcuminoid therapy significantly reduces plasma triglycerides and increases HDL-C levels.     

Mutagenesis of the human IgA1 heavy chain tailpiece that prevents dimer assembly

OBJECTIVE: To determine the accuracy and precision of a computer-automated semen analyzer (CASA; Hamilton-Thorne Research, Beverly, MA) over a wide range of sperm concentrations. DESIGN: Prospective study using comparative measurements of sperm concentration and motility were performed using manual and CASA methods of analyses. SETTING: A hospital-based Andrology laboratory. PATIENTS: Male partners of couples undergoing infertility evaluation. MAIN OUTCOME MEASURES: Measurements of sperm concentration in the range of 1 to 200 x 10(6)/mL were performed using hemacytometers and CASA-analyzed 20 MicroCell counting chambers (Conception Technologies, Inc., La Jolla, CA). Accuracy was assessed by comparison to the hemacytometer ("gold standard"). The MicroCell counting chambers also were used for manual and CASA sperm motility determinations. RESULTS: The CASA-analyzed 20 Microcell Chamber most precisely determined sperm concentration in the 1 to 200 x 10(6)/mL range (intraclass correlation coefficient = 0.94). The hemacytometer was least precise (intraclass correlation coefficient = 0.91). There was a high degree of correlation between the manually and CASA-analyzed MicroCell Chambers in the sperm concentration range of 20 to 149 x 10(6)/mL. Above and below this range, correlation was lower. Motility was determined most precisely using the CASA-analyzed 20 MicroCell Chamber. CONCLUSIONS: The Hamilton-Thorne CASA used with the 20 MicroCell Chamber is a precise and accurate method for determining sperm concentration and motility of semen specimens with concentrations in the 20 to 149 x 10(6)/mL range. This same combination of CASA and MicroCell Chamber provides precise sperm motility results.