Thermal behavior, structure, dynamic properties of aqueous glycine solutions confined in mesoporous silica MCM-41 investigated by x-ray diffraction and quasi-elastic neutron scattering

Differential scanning calorimetry, X-ray diffraction, and quasi-elastic neutron scattering (QENS) measurements of aqueous glycine solutions confined in mesoporous silica (MCM-41) were performed at different glycine concentrations, pH, and loading ratio (=mass of glycine solution/mass of dry MCM-41) in the temperature range from 305 to 180 K to discuss the confinement effect on the thermal behavior, the structure, and the dynamic properties of the solutions. The freezing points of the confined glycine solutions decreased, compared with those of the bulk solutions. The corresponding exothermic peak due to ice formation became broader with an increase in the glycine concentration. By subtracting X-ray diffraction patterns of dry MCM-41 from those of glycine solution-loaded MCM-41, information about the structure of the confined glycine solutions was obtained. The radial distribution functions of the confined glycine solutions showed that the peaks assigned to the interaction between glycine molecules and the surface silanol (Si-OH) groups of MCM-41 at pH = 5 were observed, in contrast to the case at pH = 2. The QENS data on H/D substituted aqueous glycine solutions gave the translational diffusion coefficients and the residence time of glycine and water molecules confined in MCM-41 individually. The activation energy of the diffusion coefficient of a glycine molecule at pH = 5 was larger than that at pH = 2. These results imply that glycine molecules locate near the pore surface of MCM-41 due to the formation of hydrogen bonding between glycine molecules and the silanol group of the MCM-41 wall at pH = 5.

Successful tocilizumab and tacrolimus treatment in a patient with rheumatoid arthritis complicated by systemic lupus erythematosus

We report a 37-year-old female of intractable rheumatoid arthritis (RA) complicated by systemic lupus erythematosus (SLE), who was successfully treated with a combination of tocilizumab (TCZ) and tacrolimus. She was diagnosed with RA when she was 21 years old, and was administered oral prednisolone, injectable gold and salazosulfapyridine, but deformity of her hands gradually developed. She developed high fever and thrombocytopenia when she was 35 years old. Renal involvement, pericarditis, positive antinuclear antibody and high level of anti-double-stranded DNA antibody were found and the patient was diagnosed with SLE. Polyarthritis and immunological abnormalities developed despite aggressive immunosuppressive therapy including high-dose corticosteroids and intravenously administered cyclophosphamide. Tacrolimus (TAC) therapy gave only partial improvement of joint symptoms. After the initiation of combination therapy with TCZ, not only was a complete remission of RA obtained, but also the serum levels of SLE markers dramatically decreased. Our report suggests the possibility that this combination therapy is effective in treating SLE as well as RA.

Postnatal development of acetohexamide reductase activities in microsomes and cytosol of rat liver

The postnatal development of acetohexamide reductase activities in liver microsomes and cytosol were examined in male rats. The developmental pattern of acetohexamide reductase activity in liver microsomes was distinguished from that in liver cytosol. Furthermore, acetohexamide reductase activity in liver microsomes was effectively suppressed by castration, but the activity in liver cytosol was not affected by castration. These results clearly indicate that enzymes with physiologically different roles can catalyze the metabolic reduction of acetohexamide in rat liver.