Increased activation product of complement 4 protein in plasma of individuals with schizophrenia

Structural variation in the complement 4 gene (C4) confers genetic risk for schizophrenia. The variation includes numbers of the increased C4A copy number, which predicts increased C4A mRNA expression. C4-anaphylatoxin (C4-ana) is a C4 protein fragment released upon C4 protein activation that has the potential to change the blood–brain barrier (BBB). We hypothesized that elevated plasma levels of C4-ana occur in individuals with schizophrenia (iSCZ). Blood was collected from 15 iSCZ with illness duration < 5 years and from 14 healthy controls (HC). Plasma C4-ana was measured by radioimmunoassay. Other complement activation products C3-ana, C5-ana, and terminal complement complex (TCC) were also measured. Digital-droplet PCR was used to determine C4 gene structural variation state. Recombinant C4-ana was added to primary brain endothelial cells (BEC) and permeability was measured in vitro. C4-ana concentration was elevated in plasma from iSCZ compared to HC (mean = 654 ± 16 ng/mL, 557 ± 94 respectively, p = 0.01). The patients also carried more copies of the C4AL gene and demonstrated a positive correlation between plasma C4-ana concentrations and C4A gene copy number. Furthermore, C4-ana increased the permeability of a monolayer of BEC in vitro. Our findings are consistent with a specific role for C4A protein in schizophrenia and raise the possibility that its activation product, C4-ana, increases BBB permeability. Exploratory analyses suggest the novel hypothesis that the relationship between C4-ana levels and C4A gene copy number could also be altered in iSCZ, suggesting an interaction with unknown genetic and/or environmental risk factors.

Experimental and Theoretical Study of the Silicon-Hydrogen Bond Activation by Rhodium Dicarbonyl Complex in Solution

The photoreactivity of hydrotris-(3,5-dimethylpyrazolyl)boratedicarbonylrhodium(I) or HB(Pz*)3Rh(CO)2 complex has been studied at room-temperature n-pentane solution in the presence of 0.05 M Et3SiH (Et = C2H5). The IR spectra show that the decline of νCO parent complex at 1980 and 2054 cm-1 is followed by growing bands at 2029 and 2020 cm-1. In light of the photolysis of the parent complex in neat n-pentane solution the feature at 2020 cm-1 is tentatively assigned to the νCO band of the Si-H bond activation product. Upon standing in the dark, the 2020 cm-1 increases slightly in contrast with the 2029 cm-1 peak which decreases over time. These observations raise question whether the intensity increase of the 2020 cm-1 peak occurs unimolecularly resulting from the intramolecular rearrangement of the C-H bond activation of Et3SiH or bimolecularly as a result of the elimination of the C-H bond activation of the solvent and subsequent re-addition of the Si-H bond of the Et3SiH ligand. To gain more insight to reaction dynamics of the Si-H bond activation, the experimental results are compared to the photolysis of the parent complex in neat Et3SiH. The quantum efficiency (ϕSi-H) of this photoreaction yields a low value of 0.16. The results indicate that the Si-H bond activation is facilitated by intramolecular rearrangement mode. In addition, a theoretical study was conducted using density functional study at B3LYP/LanL2DZ level of theory, and the findings implicate that the final complex product was produced by the Si-H bond activation of Et3SiH.

A High-Performance Alumina Desiccant

The effect of the synthesis conditions – features and content of an alkali used for hydration of the gibbsite thermal activation product, and the content of nitric acid (acidity modulus) used to obtain the extrusion paste – on the properties of alumina desiccants was studied. The synthesized desiccant outperforms foreign and Russian analogs in dynamic capacity (above 10.0 g/100 g) at close values of specific surface area (ca. 300 m2/g) and static capacity (20–22 g/100 g). The desiccant has a high strength (above 8.0 MPa). Its application can increase the performance of existing adsorbers and decrease the cost of sorbent regeneration, which is certainly of practical interest.