Protein-Degrading Enzymes in Osteoarthritis.

OBJECTIVE: TGFß1 plays an important role in the metabolism of articular cartilage and bone; however, the pathological mechanism and targets of TGFß1 in cartilage degradation and uncoupling of subchondral bone remodeling remain unclear. Therefore, in this study, we investigated the relationship between TGFß1 and major protein-degrading enzymes, and evaluated the role of high levels of active TGFß1 in the thickening of subchondral bone and calcification of articular cartilage. MATERIALS AND METHODS: The expression of TGFß1 and protein-degrading enzymes in clinical samples of articular cartilage and subchondral bone obtained from the knee joint of patients with osteoarthritis was detected by immunohistochemistry. The expression levels of TGFß1, MMP-3, MMP-13 and IL-1ß in cartilage and subchondral bone tissues were detected by absolute real-time quantitative RT-PCR. The expression of TGFß1, nestin and osterix in subchondral bone was detected by Western blot analysis and immunohistochemistry. The degree of subchondral bone thickening was determined by micro-computed tomography (CT) imaging. RESULTS: Expression of TGFß1 and cartilage-degrading enzymes was higher in the cartilage-disrupted group than that in the intact group. Furthermore, expression of TGFß1, nestin and osterix was significantly higher in the OA group than that in the control group. Micro-CT imaging showed that in the OA group, the subchondral bone plate is thickened and the density is increased. The trabecular bone structure is thick plate-like structure, the thickness of the trabecular bone is increased and the gap is small. CONCLUSIONS: The data suggest that highly active TGFß1 activates the expression of cartilage-degrading enzymes. Abnormally activated TGFß1 may induce formation of the subchondral bone and expansion of the calcified cartilage area, eventually leading to degradation of the cartilage tissue.

How job stress influences job performance among Chinese healthcare workers: a cross-sectional study

OBJECTIVES@#Public service motivation refers to the idea of commitment to the public service, pursuit of the public interest, and the desire to perform work that is worthwhile to society. This study investigates how challenge stress and hindrance stress influence job performance among healthcare workers in Chinese public hospitals. It has also examined the mediating effect of public service motivation.@*METHODS@#Data of 1594 healthcare workers were obtained from typical public hospitals in eastern, central, and western China. To test our hypotheses, we used descriptive statistical analysis, correlation analysis, structural equation modeling, and subgroup analysis to investigate the sample.@*RESULTS@#Challenge stress and hindrance stress were strongly correlated among healthcare workers in Chinese public hospitals (β = 0.59; p < 0.001). Challenge stress was significantly positively associated with public service motivation (β = 0.14; p < 0.001) and job performance (β = 0.13; p < 0.001). Hindrance stress was significantly negatively associated with public service motivation (β = - 0.27; p < 0.001) and job performance (β = - 0.08; p < 0.05). Public service motivation was directly positively associated with job performance (β = 0.58; p < 0.001), and it indirectly mediated the association between job stress and job performance.@*CONCLUSIONS@#This study provides important empirical evidence on the effects of job stress and public service motivation on job performance among healthcare workers in Chinese public hospitals. Job performance may be raised by limiting hindrance stress, which provides moderate challenge stress and increases public service motivation.

Perceived social support and presenteeism among healthcare workers in China: the mediating role of organizational commitment

OBJECTIVES@#We assessed the role of social support in presenteeism by examining organizational commitment among Chinese healthcare workers.@*METHODS@#One thousand four hundred thirty-four healthcare workers from 6 hospitals in 4 Chinese cities completed a questionnaire measuring presenteeism, social support, and organizational commitment. With organizational commitment as the mediator, regression analyses and structural equation modeling were used to test the model.@*RESULTS@#Organizational commitment was directly inversely associated with presenteeism (β = - 0.42, p 0.05). The correlation between supervisor support and coworker support was significant (β = 0.71, p <0.001). Supervisor support and coworker support were significantly positively associated with organizational commitment (β = 0.41, p < 0.001, and β = 0.14, p < 0.001, respectively).@*CONCLUSIONS@#Supervisor support was more important in promoting organizational commitment, while coworker support was more effective in reducing presenteeism. The mediating effect of organizational commitment was significant.