Human gingival mesenchymal stem cells-lyosecretome attenuates adverse effect of hydrogen peroxide-induced oxidative stress on osteoblast cells.

Objective: To determine total protein content, antioxidant activity, and protective ability of lyophilized human gingival mesenchymal stem cells (hGMSCs)-secretome in hydrogen peroxide (H2O2) induced oxidative stress model. Methods: Human GMSCs were cultured to obtain a conditioned medium (secretome), then lyophilized to produce lyosecretome. Total protein was determined by bicinchoninic acid assay (BCA) and SDS-PAGE to improve protein measurements. Antioxidant concentration was measured by ABTS assay, while the protective ability of lyosecretome against oxidative stress was determined by the metabolic activity of osteoblast cells. The study group was divided into a control group (culture medium) and a lyosecretome treatment group (0.0; 0.157, 0.313, 0.625, 1.25, 2.5, 5, and 10 mg/mL + H2O2). Results: Lyosecretome had a protein concentration of 2086.00 ± 0.20 µg/ml, with a molecular weight of 174, 74, 61, 55, and 26 kDa, which are thought to facilitate cell migration, as well as bind cytokines and growth factors. Lyosecretome also provided the highest antioxidant activity of 93.51% at a concentration of 4.8 mg/ml, with an IC50 value of 2.08 mg/ml. The highest cell metabolic activity (79.53 ± 2.41%) was shown in the 1.25 mg/ml lyosecretome treatment group. All concentrations of hGMSC-lyosecretome attenuate the adverse effect of H2O2-induced oxidative stress. Conclusion: Lyosecretome obtained from hGMSCs can maintain metabolic activity in osteoblast cells as protection against H2O2 oxidative stress.

Individual differences in the impact of vicarious racism: African American students react to the George Zimmerman trial.

OBJECTIVE: This research focused on how race-based rejection sensitivity (RS-Race) and components of racial identity intensify negative psychological reactions to an incident of vicarious racism. We examined how these individual difference variables directly and/or indirectly predicted African American students' reactions to the trial of George Zimmerman in the killing of the African American teenager, Trayvon Martin. METHOD: In Study 1, 471 African American students completed measures of RS-Race, thought intrusions about the Zimmerman trial, and outcome variables (negative affect about the Zimmerman trial and forgiveness for Mr. Zimmerman). In Study 2, 304 African American students completed measures of racial identity (centrality, private regard, and public regard), thought intrusions about the Zimmerman trial, negative affect, and forgiveness. RESULTS: In Study 1, higher RS-Race was either directly and/or indirectly (via thought intrusions) related to more negative affect and lower forgiveness. In Study 2, high racial centrality and low public regard either directly and/or indirectly (via thought intrusions) predicted more negative affect and lower forgiveness. CONCLUSIONS: RS-Race and specific components of racial identity are likely to sensitize African Americans to incidents of racism that happen to other African Americans, leading to negative psychological reactions when these events occur. (PsycINFO Database Record

Studies on naturally occurring proteinous inhibitor for transmethylation reactions.

An inhibitor for S-adenosyl-L-methionine (AdoMet)-dependent methyltransferases has been purified from rat liver particulate fraction to apparent homogeneity, as judged by high-performance liquid chromatography, two-dimensional paper electrophoresis and isoelectric focusing chromatography. This inhibitor molecule, which is composed of 27 amino acid residues with an additional fluorescent chromophore, is rich in glycine, contains no basic amino acid, and has an isoelectric point (pI) of 3.70. A single absorption peak was observed at 248 nm in acidic as well as in neutral media, while two peaks were detected in alkaline medium at 206 nm and 248 nm. The former peak was found to be quite labile. The fluorescent spectra with excitation peak at 285 nm and emission peak at 358 nm are greatly influenced by the pH, being the highest in alkaline medium. The purified inhibitor inhibits all the AdoMet-dependent methyltransferases examined.

The alloantibody response and active enhancement of some rat renal allografts.

Lewis rats that were given injections of 10(6) to 10(8) (Lewis X Brown Norway) F1 hybrid bone marrow cells produce predominantly, if not exclusively, 19S lymphocytotoxic antibodies. A number of Lewis rats that received transplants of perfused renal allografts from bone marrow donors at, or near, the peak of IgM response survival for well over 200 days with good renal function and no histological evidence of chronic rejection. All long-surviving rats had detectable lymphocytotoxic antibodies up to 120 days after allografting; late enhancing antibodies had the restricted specificity possibly identical or similar to anti-I region antisera. All rats bearing prolonged renal allografts were unable to accept donor-specific skin grafts or to respond with specific lymphocytotoxic antibodies following skin grafting. The possible involvement of non-complement-fixing 19S alloantibodies in active enhancement of rat renal allografts is discussed.