Dietary Protein Intake in Relation to the Risk of Osteoporosis in Middle-Aged and Older Individuals: A Cross-Sectional Study.

OBJECTIVES: Dietary protein intake is of great significance for the bone health of middle-aged and elderly people. This study is aimed to explore the relationships between dietary protein intake and the risk of osteoporosis in middle-aged and older individuals among US population. METHODS: Based on the National Health and Nutrition Examination Survey (NHANES), this study includes a total of 20497 participants during 2005-2008, and identify 4707 middle-aged and older people aged 45 years or above. Demographic data and relevant dietary intake information are acquired through in-home management questionnaires. The logistic regression models are established to identify the odds ratio (OR) and 95% confidence interval (CI) of OP in each quartile category of energy-adjusted dietary protein intake. The receiver operating characteristic (ROC) curve is applied to explore the optimal cut-off value of daily dietary protein intake for predicting risk of OP. RESULTS: 442 participants with OP are identified among 4707 middle-aged and older people, and the dietary protein intake of OP group is significantly lower than that of non-OP group (P<0.001). The logistic regression analysis shows that with the increase of daily dietary protein intake, the prevalence of OP in each quartile category decreases gradually (P<0.001). This trend is not altered in univariate model (P<0.001), as well as the adjustments for the covariates of age and BMI (Model 1, P<0.001), the covariates of sex (Model 2, P=0.036), the covariates of smoking, drinking alcohol, education, ratio of family income to poverty, hypertension and diabetes (Model 3, P<0.001), and the covariates of dietary intake (Model 4, P=0.008). Moreover, we also identify that the daily dietary protein intake of 61.2g is the optimal cut-off value for predicting risk of OP. CONCLUSION: In general, among US population, the lower daily dietary protein intake is positively related to the ascending risk of OP in middle-aged and older individuals.

O-GlcNAcylation promotes malignant phenotypes of bladder cancer cells.

O-GlcNAcylation (O-GlcNAc) is a posttranslational modification that is mediated by O-GlcNAc-transferase (OGT) and reversed by O-GlcNAcase (OGA). Increasing evidence indicates that protein O-GlcNAcylation is increased in various types of cancer. In the present study, we aimed to evaluate the expression and function of both OGT and OGA in bladder cancer cells in vitro and in vivo. Expression data of OGT and OGA at the mRNA level was obtained from the Oncomine database. Effects of OGT and OGA on cell proliferate, invasive, and migratory abilities were assessed using MTT, wound healing, cell invasive assay, and cell cycle analysis. In vivo assay was also performed in nude mice. The results revealed that the expression of OGT in bladder cancer tissues was higher than that of normal tissues, while the OGA level was found to be lower in cancer tissues. We also found that knockdown of OGT could inhibit cell proliferation, migration, invasion, and induce cell cycle arrest, while these are reversed when OGA is inhibited. We also observed that O-GlcNAcylation could promote tumor formation in vivo, compared with a negative control. In summary, this study describes the oncogenic role of O-GlcNAcylation in bladder cancer cells.

Quantitative investigations of cell-bubble interactions using a foam fractionation technique.

Previous work by the authors and others has shown that suspended animal cell damage in bioreactors is caused by cell-bubble interactions, regardless whether the bubbles are from bubble entrainment or direct gas sparging. As approach to measure the adsorptivity of animal cells to bubbles, a modified batch foam fractionation technique has been developed in this work and proven to be applicable. By using this technique, the number of cells absorbed per unit bubble surface area and the adsorption coefficients have been measured to quantify hybridoma cell-bubble interactions, and the preventive effects of serum and Pluronic F68 on these interactions. It was demonstrated quantitatively that the hybridoma cells adhere to bubbles spontaneously and significant numbers exist in the foam, and that both the serum and Pluronic F68 provide strong prevention to these cell-bubble interactions. The results obtained provide criteria for bioreactor operation and medium formulation to prevent cell-bubble interactions and cell damage in the culture processes.