In this study, adult human bone marrow-derived stromal cells (hBMSCs) were cultured in extracts of magnesium (Mg) and the Mg alloys AZ91D and NZ30K for 12 days. We studied the indirect effects of Mg alloys on hBMSC viability. Alkaline phosphatase activity and the expression of osteogenic differentiation marker genes were used to evaluate the effects of the Mg alloys on the osteogenic differentiation of hBMSCs. The results indicate that

The purpose of this single-center, randomized, controlled trial was to report on the 2-year outcomes of proximal humerus fractures in elderly patients treated with open reduction and internal fixation (ORIF) with either a locking plate or shoulder hemiarthroplasty. Thirty-two patients (87% women) with a mean age of 71.9 years (range, 67-86 years) were treated with ORIF with either a locking plate or shoulder hemiarthroplasty after shoulder injury. The main outcome measures were the Constant score, Disabilities of the Arm, Shoulder and Hand (DASH) score, and health-related quality of life (HRQoL) according to the EQ-5D (EuroQol Group, Rotterdam, The Netherlands). At final 2-year follow-up, DASH and pain scores favored the shoulder hemiarthroplasty group. Mean flexion was 129° in the shoulder hemiarthroplasty group and 117° in the ORIF group (P=.27), and mean abduction was 123° in the shoulder hemiarthroplasty group and 111° in the ORIF group (P=.41). In the shoulder hemiarthroplasty group, the EQ-5D index score decreased from 0.85±0.21 before injury to 0.65±0.14 at 4 months postoperatively. The score was 0.79±0.24 at 12 months postoperatively and 0.81±0.17 at 24 months postoperatively. The results of this study indicate an advantage in functional outcomes and HRQoL favoring shoulder hemiarthroplasty compared with ORIF with a locking plate, although most outcomes were not significantly different.

Quorum sensing (QS) signals are used by bacteria to regulate biological functions in response to cell population densities. Cyclic diguanosine monophosphate (c-di-GMP) regulates cell functions in response to diverse environmental chemical and physical signals that bacteria perceive. In , the QS signal receptor RpfR degrades intracellular c-di-GMP when it senses the QS signal-2-dodecenoic acid, also called diffusible signal factor (BDSF), as a proxy for high cell density. However, it was unclear how this resulted in control of BDSF-regulated phenotypes. Here, we found that RpfR forms a complex with a regulator named GtrR (BCAL1536) to enhance its binding to target gene promoters under circumstances where the BDSF signal binds to RpfR to stimulate its c-di-GMPphosphodiesterase activity. In the absence of BDSF, c-di-GMP binds to the RpfR-GtrR complex and inhibits its ability to control gene expression. Mutations in and had overlapping effects on both the transcriptome and BDSF-regulated phenotypes, including motility, biofilm formation, and virulence. These results show that RpfR is a QS signal receptor that also functions as a c-di-GMP sensor. This protein thus allows to integrate information about its physical and chemical surroundings as well as its population density to control diverse biological functions including virulence. This type of QS system appears to be widely distributed in beta and gamma proteobacteria.

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