Heat-Killed Staphylococcus aureus Induces Bone Mass Loss through Telomere Erosion.

The mechanism of systemic osteoporosis caused by chronic infection is not completely clear, and there is a lack of reasonable interventions for this disease. In this study, heat-killed S. aureus (HKSA) was applied to simulate the inflammation caused by the typical clinical pathogen and to explore the mechanism of systemic bone loss caused by it. In this study, we found that the systemic application of HKSA caused bone loss in mice. Further exploration found that HKSA caused cellular senescence, telomere length shortening, and telomere dysfunction-induced foci (TIF) in limb bones. As a well-known telomerase activator, cycloastragenol (CAG) significantly alleviated HKSA-induced telomere erosion and bone loss. These results suggested that telomere erosion in bone marrow cells is a possible mechanism of HKSA-induced bone loss. CAG may protect against HKSA-induced bone loss by alleviating telomere erosion in bone marrow cells.

Expression of RhoA and COX-2 and their roles in the occurrence and progression of brain glioma.

This study was conducted to detect the expression of RhoA and COX-2 in the brain glioma and to discuss their roles in the occurrence and progression of brain glioma. Brain glioma tissues were collected from 22 cases with brain glioma by surgical resection (tumor group); normal brain tissues were collected from 15 cases with brain trauma by surgical resection (healthy group). Western Blot and immunohistochemistry were applied to detect the expression of RhoA and COX-2 in the tissues. The brain glioma cell lines with silenced RhoA expression or silenced COX-2 expression were used to analyze the roles of RhoA and COX-2 in the occurrence and progression of brain glioma through the cell proliferation and invasion/migration assays. The relative expression of RhoA and COX-2 in the brain glioma was 0.82±0.13 and 0.75±0.14, respectively, which was significantly higher than that in the normal brain tissues (0.12±0.08 and 0.043±0.14) (P<0.05). The percentage of RhoA-positive brain glioma cells and COX-2-positive cells was 75.32±15.02% and 82.39±17.82%, respectively; it was significantly higher than that of the normal brain tissues (17.03±7.72 and 5.83±4.01) (P<0.05). As compared with glioma cell line SHG-44, the relative proliferation rate of C8-D9 and E5-B9 was 20.72% and 25.45%, respectively; the relative invasion/migration rate was 20.91% and 20.97%, respectively. The G0/G1 phase decreased significantly (P<0.05) and significantly increased in stage S and G2/M (P<0.05). Both RhoA and COX-2 were upregulated in the brain glioma tissues; their over-expression contributed to the proliferation and invasion/migration of the brain glioma cells.

Remodeling Microenvironment for Implant-Associated Osteomyelitis by Dual Metal Peroxide.

Implant-associated osteomyelitis (IAOM) is characterized by bone infection and destruction; current therapy of antibiotic treatment and surgical debridement often results in drug resistance and bone defect. It is challenging to develop an antibiotic-free bactericidal and osteogenic-enhanced strategy for IAOM. Herein, an IAOM-tailored antibacterial and osteoinductive composite of copper (Cu)-strontium (Sr) peroxide nanoparticles (CSp NPs), encapsulated in polyethylene glycol diacrylate (PEGDA) (CSp@PEGDA), is designed. The dual functional CSp NPs display hydrogen peroxide (H2O2) self-supplying and Fenton catalytic Cu2+ ions' release, generating plenty of hydroxyl radical (•OH) in a pH-responsive manner for bacterial killing, while the released Sr2+ promotes the in vitro osteogenicity regarding cell proliferation, alkaline phosphatase activity, extracellular matrix calcification, and osteo-associated genes expression. The integration of Cu2+ and Sr2+ in CSp NPs together with the coated PEGDA hydrogel ensures the stable and sustainable ion release during short- and long-term periods. Benefitted from the injectablity and photo-crosslink ability, CSp@PEGDA is able to thoroughly fill the infectious site and gelate in situ for bacterial elimination and bone regeneration, which is verified through in vivo evaluation using a clinical-simulating IAOM mouse model. These favorable abilities of CSp@PEGDA precisely meet the multiple therapeutic needs and pave a promising way for implant-associated osteomyelitis treatment.

Global competence of medical students: An assessment scale and preliminary investigation in China.

INTRODUCTION: The importance of global competence has been acknowledged in medical care as well as medical education. This study aims to develop a scale assessing the global competence of medical students, determine the factor structure and internal consistency of the scale and explore the underlying factors influencing the global competence of Chinese medical students in 8-year programs. METHODS: A questionnaire (Global Competence Assessment Scale for Medical Students, MS-GCAS) was developed, and a cross-sectional multicenter survey was conducted in 1062 medical students from 10 medical schools in China. Questionnaire data were analyzed using exploratory factor analysis and multiple linear regression. RESULTS: The exploratory factor analysis revealed a three-factor scale. The MS-GCAS has good internal consistency (Cronbach's alpha = 0.79 to 0.87). In the multivariate regression analyses, medical education stage (p<0.05), the frequency of communicating with foreigners (p<0.001), multilingual ability (p<0.05) and grade level (p<0.05) are associated with the MS-GCAS scores. DISCUSSION: The MS-GCAS has the potential to serve as a tool to measure the global competence of medical students. This three-factor scale can be used by medical education researches to improve future versions. Medical schools should conduct further educational reforms to promote students' global competence.

The Potential Significance of ABO Genotyping for Donor Selection in Kidney Transplantation.

Background: The ABO blood group system is clinically important in kidney transplantation, but ABO genotyping fails to attract sufficient attention in some countries and regions. We identified one case of early graft dysfunction due to an ABO genotype mismatch. Here, we performed ABO genotyping in blood samples, analyzed grouping discrepancies, and investigated the weak A subgroup frequency in kidney transplantation candidates. Methods: Blood samples from 302 uremic patients with grouping discrepancies and 356 uremic patients with type A blood were analyzed using standard serologic serotyping techniques. The ABO genotypes and alleles were analyzed by polymerase chain reaction sequence-specific primer (PCR-SSP) and sequence-based typing (PCR-SBT). Results: All 302 uremic patients with grouping discrepancies carried weak ABO subgroup alleles and 77.48% carried irregular ABO antibodies. The discrepancy rate between serotyping and genotyping was 42.38%, and the mismatching rate of donor selection according to serotype reached 88.74%. And 2.53% of 356 uremic patients with type A blood were determined to be in the weak A subgroup, which was a higher percentage than that observed in the healthy Chinese population (0.53%) by serological screening, but much lower than that observed in Caucasians (20%). Conclusion: We revealed the high risk of blood type misjudgment and genetically ABO-mismatched transplantation if serological test was performed only in blood-group typing. Improved precision of ABO genotyping is crucial for successful kidney transplantation and reasonable organ allocation.

[Characteristics of BK polymavirus infection in kidney transplant recipients].

OBJECTIVE: To analyze the characteristics of BK polymavirus (BKV) infection and the optimal time window for intervention in kidney transplant recipients (KTRs). METHODS: We retrospectively analyzed the clinical data and treatment regimens in 226 KTRs in our center between January, 2013 and January, 2018. Among the recipients, 157 had a urine BKV load ≥1.0×104 copy/mL after transplantation, and 69 had a urine BKV load below 1.0×104 copy/mL (control group). RESULTS: Among the 157 KTRs, 60 (38.2%) recipients were positive for urine BKV, 66 (42.0%) had BKV viruria, and 31(19.7%) had BKV viremia. The incidence of positive urine occult blood was significantly higher in BKV-positive recipients than in the control group (P < 0.05). The change of urine BKV load was linearly related to that of Tacrolimus trough blood level (r2=0.351, P < 0.05). In urine BKV positive group, the average estimated glomerular filtration rate (eGFR) was below the baseline level (60 mL·min-1·1.73 m-2) upon diagnosis of BKV infection reactivation, and recovered the normal level after intervention. In patients with BKV viruria and viremia, the average eGFR failed to return to the baseline level in spite of improvement of the renal function after intervention. CONCLUSIONS: Positive urine occult blood after transplantation may be associated with BKV infection reactivation in some of the KTRs. BKV infection is sensitive to changes of plasma concentration of immunosuppressive agents. Early intervention of BKV replication in KTRs with appropriate dose reduction for immunosuppression can help to control virus replication and stabilize the allograft function.