Biomechanical effects of femoral prosthesis misalignment on the structure of the lateral compartment during medial unicompartmental knee arthroplasty in osteoporotic patients.

BACKGROUND: This study aims to investigate the impact of varying coronal alignments of femoral prostheses on stress and strain distributions within the lateral compartment following unicompartmental knee arthroplasty (UKA) in patients with normal bone density and osteoporosis using finite element analysis. Additionally, it examines the relationship between osteoporosis and the progression of osteoarthritis in the lateral compartment postoperatively. METHODS: UKA models were developed for both normal bone and osteoporotic conditions using a validated finite element model of the knee. Seven alignment conditions for the femoral prosthesis were simulated: 0° (neutral alignment), varus angles of 3°, 6°, and 9°, and valgus angles of 3°, 6°, and 9°, resulting in a total of 14 scenarios. Stress and strain distributions in the meniscus, tibial cartilage, and femoral cartilage of the lateral compartment were evaluated. RESULTS: The results indicated that stress and strain in the meniscus, tibial cartilage, and femoral cartilage of the lateral compartment increased with greater varus alignment and decreased with greater valgus alignment in both normal and osteoporotic models. At equivalent alignment angles, stress and strain were consistently higher in the osteoporotic model (M2) compared to the normal bone model (M1), although the peak equivalent stress in the tibial cartilage was lower in the M2 model than in the M1 model. CONCLUSIONS: In patients with osteoporosis undergoing fixed-bearing medial UKA, varus malalignment of the femoral prosthesis can lead to increased stress and strain in the lateral compartment's meniscus, tibial cartilage, and femoral cartilage. These findings suggest that osteoporosis may contribute to abnormal stress and strain distributions in the lateral compartment following UKA, potentially accelerating the progression of osteoarthritis in this region postoperatively.

[Effect of Kartogenin combined with adipose-derived stem cells on tendon-bone healing after anterior cruciate ligament reconstruction].

Objective: To investigate the effect of Kartogenin (KGN) combined with adipose-derived stem cells (ADSCs) on tendon-bone healing after anterior cruciate ligament (ACL) reconstruction in rabbits. Methods: After the primary ADSCs were cultured by passaging, the 3rd generation cells were cultured with 10 µmol/L KGN solution for 72 hours. The supernatant of KGN-ADSCs was harvested and mixed with fibrin glue at a ratio of 1∶1; the 3rd generation ADSCs were mixed with fibrin glue as a control. Eighty adult New Zealand white rabbits were taken and randomly divided into 4 groups: saline group (group A), ADSCs group (group B), KGN-ADSCs group (group C), and sham-operated group (group D). After the ACL reconstruction model was prepared in groups A-C, the saline, the mixture of ADSCs and fibrin glue, and the mixture of supernatant of KGN-ADSCs and fibrin glue were injected into the tendon-bone interface and tendon gap, respectively. ACL was only exposed without other treatment in group D. The general conditions of the animals were observed after operation. At 6 and 12 weeks, the tendon-bone interface tissues and ACL specimens were taken and the tendon-bone healing was observed by HE staining, c-Jun N-terminal kinase (JNK) immunohistochemical staining, and TUNEL apoptosis assay. The fibroblasts were counted, and the positive expression rate of JNK protein and apoptosis index (AI) were measured. At the same time point, the tensile strength test was performed to measure the maximum load and the maximum tensile distance to observe the biomechanical properties. Results: Twenty-eight rabbits were excluded from the study due to incision infection or death, and finally 12, 12, 12, and 16 rabbits in groups A-D were included in the study, respectively. After operation, the tendon-bone interface of groups A and B healed poorly, while group C healed well. At 6 and 12 weeks, the number of fibroblasts and positive expression rate of JNK protein in group C were significantly higher than those of groups A, B, and D (P<0.05). Compared with 6 weeks, the number of fibroblasts gradually decreased and the positive expression rate of JNK protein and AI decreased in group C at 12 weeks after operation, with significant differences (P<0.05). Biomechanical tests showed that the maximum loads at 6 and 12 weeks after operation in group C were higher than in groups A and B, but lower than those in group D, while the maximum tensile distance results were opposite, but the differences between groups were significant (P<0.05). Conclusion: After ACL reconstruction, local injection of a mixture of KGN-ADSCs and fibrin glue can promote the tendon-bone healing and enhance the mechanical strength and tensile resistance of the tendon-bone interface.

A review of food preservation based on zein: The perspective from application types of coating and film.

The application of zein in food preservation was discussed from a unique perspective of application types, including coating and film. For the study of coating, edibility is considered because the coating adheres to the surface of food directly. For the study of film, plasticizers improve their mechanical properties, while barrier performance and antibacterial performance are achieved by nanoparticles; the incorporation of polyphenols is mainly due to their antibacterial and antioxidant properties; other biopolymers realize the complementarity between zein and biopolymers within films. In the future, the interaction between the edible coating and food matrix needs to be concerned. The mechanism of various exogenous additives and zein in the film should be noticed. Importantly, food safety and the possibility of large-scale application should be followed. Additionally, the intelligent response is one of the key development directions of zein-based film in the future.

A Single Catalytic Endolysin Domain Plychap001: Characterization and Application to Control Vibrio parahaemolyticus and Its Biofilm Directly.

Endolysins are enzymes used by bacteriophages to cleave the host cell wall in the final stages of the lytic cycle. As such, they are considered promising antibacterial agents for controlling and combating multidrug-resistant (MDR) bacteria. However, the application of endolysins targeting Gram-negative bacteria is greatly hindered by the outer membrane on these bacteria. Lysqdvp001, an endolysin with modular structure, has been reported as one of the most efficient endolysins against the Gram-negative bacterium Vibrio parahaemolyticus. In this study, Plychap001, the truncated recombinant catalytic domain of Lysqdvp001, was demonstrated to exhibit a direct and efficient bactericidal activity against broad spectrum of V. parahaemolyticus strains. Plychap001 was shown to be highly stable and retain high bactericidal activity at high temperatures, over a wide pH range, and at high NaCl concentrations. Plychap001 also exhibited a synergistic lytic effect with EDTA. Additionally, Plychap001 was found to efficiently degrade and eliminate V. parahaemolyticus biofilms on polystyrene surfaces. Our study establishes Plychap001 as a promising method for controlling V. parahaemolyticus in the food industry.