A comparison of biomechanical changes on femoral head following rotational acetabular osteotomy and eccentric rotational acetabular osteotomy in normal cadaveric hip.

PURPOSE: Both rotational acetabular osteotomy (RAO) and eccentric rotational acetabular osteotomy (ERAO) are effective procedures for young patients with developmental dysplasia of the hip. However, no comparative study of biomechanical changes has been reported following these two procedures. We therefore explored the stress changes on femoral head after RAO and ERAO under different load conditions. MATERIALS AND METHODS: Twelve female cadaveric hips without deformity were divided into RAO group and ERAO group. Stress value on femoral head was measured preoperatively and postoperatively after the vertical force was loaded on the cadaveric spine from 0 to 500 N. Stress change value was then calculated base on the measurements. RESULTS: In the RAO group, preoperative stress increased when loading on spine became larger, but postoperative stress changed its increasing trend into decreasing when the load was greater than 200 N (turning point). Same phenomenon was found in the ERAO group (turning point was 300 N). However, the difference between preoperative and postoperative stress was not statistically significant in both RAO and ERAO groups. Stress change value from each procedure showed similar trends. With the load growth, stress change increased firstly and then decreased, but the difference between RAO and ERAO was not statistically significant. CONCLUSIONS: Both RAO and ERAO could correct the abnormal biomechanical effect of dysplastic hip; moreover, they may have similar biomechanical effects on femoral head, obtaining the same clinical outcomes. Non-biomechanical factors (surgical trauma, technical complexity, etc.) also play important roles in procedure selection.

PFOS Exposure Promotes Hepatotoxicity in Quails by Exacerbating Oxidative Stress and Inflammation-Induced Apoptosis through Activating TLR4/MyD88/NF-κb Signaling.

PFOS is a ubiquitous pollutant garnering considerable attention due to its deleterious effects on both human and animal health. Given the poultry industry's intimate link with human health, investigating PFOS's impact on quails is crucial. PFOS readily accumulates in the liver, causing hepatotoxicity, yet its molecular mechanisms remain elusive. In our study, we fed quail diets contaminated with varying PFOS concentrations (12.5, 25, and 50 mg/kg) and observed dose-dependent liver damage in quails. The results show that PFOS damages mitochondrial structure, increases ROS levels, and downregulates antioxidants to promote oxidative stress damage in hepatocytes. PFOS also upregulated pro-inflammatory molecules (TNF-α, IL-1ß, and IL-6) while downregulating the anti-inflammatory factor IL-10, activating the TLR4//MyD88/NF-κB signaling pathway, thereby potentiating liver inflammation. Then, oxidative stress and inflammation by PFOS induce apoptosis in quail hepatocytes through the mitochondrial pathway, with severity closely related to hepatotoxicity. In conclusion, PFOS induces mitochondrial apoptosis by exacerbating oxidative stress and inflammation by activating the TLR4/MyD88/NF-κB signaling pathway, ultimately leading to hepatotoxicity in quails.

Presence of interleukin-17C in the tissue around aseptic loosened implants.

PURPOSE: The most common long-term complication of joint arthroplasty is aseptic loosening. The proinflammatory cytokines secreted by macrophages are involved in aseptic loosening. Recently, a novel proinflammatory cytokine IL-17C was reported to participate in inflammatory diseases by synergising with proinflammatory cytokines. However, the relationship between IL-17C and the aseptic loosening is unclear. METHODS: The tissues around aseptic loosened implants were collected during revision surgery and handled by formalin fixation and embedded in paraffin. The presence of IL-17C in the tissues around the aseptic loosened implants was investigated in 12 aseptic loosening patients using immunofluorescence. RESULTS: The presence of IL-17C protein in the tissues around aseptic loosened implants was detected by immunofluorescence. There are no statistical differences between optical density of IL-17C in aseptic loosening samples and in rheumatoid arthritis samples (positive control). CONCLUSIONS: These results suggest the presence of IL-17C in aseptic loosening. Interleukin-17C was related to the inflammation of aseptic loosening, possibly by contributing to the inflammation and osteolysis in the tissues surrounding aseptic loosened implants.

High activity and selectivity of single palladium atom for oxygen hydrogenation to H2O2.

Nanosized palladium (Pd)-based catalysts are widely used in the direct hydrogen peroxide (H2O2) synthesis from H2 and O2, while its selectivity and yield remain inferior because of the O-O bond cleavage from both the reactant O2 and the produced H2O2, which is assumed to have originated from various O2 adsorption configurations on the Pd nanoparticles. Herein, single Pd atom catalyst with high activity and selectivity is reported. Density functional theory calculations certify that the O-O bond breaking is significantly inhibited on the single Pd atom and the O2 is easier to be activated to form *OOH, which is a key intermediate for H2O2 synthesis; in addition, H2O2 degradation is shut down. Here, we show single Pd atom catalyst displays a remarkable H2O2 yield of 115 mol/gPd/h and H2O2 selectivity higher than 99%; while the concentration of H2O2 reaches 1.07 wt.% in a batch.

Oral administration of live combined Bacillus subtilis and Enterococcus faecium alleviates colonic oxidative stress and inflammation in osteoarthritic rats by improving fecal microbiome metabolism and enhancing the colonic barrier.

Osteoarthritis (OA) causes intestinal damage. The protective effect of probiotics on the intestine is indeed effective; however, the mechanism of protection against intestinal damage in OA is not clear. In this study, we used meniscal/ligamentous injury (MLI) to mimic OA in rats and explored the colonic protective effects of Bacillus subtilis and Enterococcus faecium on OA. Our study showed that treatment with B. subtilis and E. faecium attenuated colonic injury and reduced inflammatory and oxidative stress factors in the serum of osteoarthritic rats. α- and ß diversity of the fecal flora were not different among groups; no significant differences were observed in the abundances of taxa at the phylum and genus levels. We observed the presence of the depression-related genera Alistipes and Paraprevotella. Analysis of fecal untargeted metabolism revealed that histamine level was significantly reduced in the colon of OA rats, affecting intestinal function. Compared to that in the control group, the enriched metabolic pathways in the OA group were primarily for energy metabolisms, such as pantothenate and CoA biosynthesis, and beta-alanine metabolism. The treatment group had enriched linoleic acid metabolism, fatty acid biosynthesis, and primary bile acid biosynthesis, which were different from those in the control group. The differences in the metabolic pathways between the treatment and OA groups were more evident, primarily in symptom-related metabolic pathways such as Huntington's disease, spinocerebellar ataxia, energy-related central carbon metabolism in cancer, pantothenate and CoA biosynthesis metabolic pathways, as well as some neurotransmission and amino acid transport, and uptake- and synthesis-related metabolic pathways. On further investigation, we found that B. subtilis and E. faecium treatment enhanced the colonic barrier of OA rats, with elevated expressions of tight junction proteins occludin and Zonula occludens 1 and MUC2 mRNA. Intestinal permeability was reduced, and serum LPS levels were downregulated in the treatment group. B. subtilis and E. faecium also regulated the oxidative stress pathway Keap1/Nrf2, promoted the expression of the downstream protective proteins HO-1 and Gpx4, and reduced intestinal apoptosis. Hence, B. subtilis and E. faecium alleviate colonic oxidative stress and inflammation in OA rats by improving fecal metabolism and enhancing the colonic barrier.

Wear particles promote endotoxin tolerance in macrophages by inducing interleukin-1 receptor-associated kinase-M expression.

Toll-like receptors (TLRs) recognizing pathogen-associated molecular patterns (PAMP) play a role in local immunity and participate in implant-associated loosening. TLRs-mediated signaling is regulated by interleukin-1 receptor-associated kinase-M (IRAK-M). Our previous studies have proved that IRAK-M is induced by wear particles in macrophages from periprosthetic tissues. In this study, the IRAK-M-related mechanisms were further explored by lipopolysaccharide (LPS) and/or titanium (Ti) particles stimulations and small interfering RNAs (siRNAs). The protein level of IRAK-M was studied using western blotting and tumor necrosis factor-α (TNF-α), and interleukin-1ß (IL-1ß) levels were measured using ELISA. Results showed that in RAW264.7 cells stimulated by LPS after Ti particle pre-exposure, IRAK-M was slightly changed, compared with LPS stimulation. And levels of TNF-α and IL-1ß in cultures stimulated by LPS first after Ti particle pre-exposure were lower than in the other two groups which were stimulated by LPS with or without Ti particles (p < 0.001), whereas there were no statistic differences between the later two (p > 0.05). The cytokines were lowest in Ti particles alone stimulation. After siRNAs silenced, IRAK-M-deficient cells exhibited increased expression of the cytokines in LPS stimulation after Ti particle pre-exposure and when stimulated with Ti particles alone. Our findings suggest that debris-induced IRAK-M decreases foreign body reactions, but at the same time, the over-expression of IRAK-M may also be detrimental on local intrusion of PAMPs or bacteria, negatively regulates the LPS-induced and TLRs-mediated inflammation and results in immunosuppression in periprosthetic tissue, which may predispose to implant-associated infections.

IRAK-M in macrophages around septically and aseptically loosened hip implants.

The most common long-term complication of joint arthroplasty is loosening, which is mediated by chronic inflammatory cytokines produced by macrophages stimulated by implant-derived debris and eventually bacterial components adherent to such debris. In this study, antiinflammatory interleukin-1 receptor-associated kinase-M (IRAK-M) was studied in macrophages in interface membranes in vivo using immunohistochemical staining and in titanium particle-stimulated macrophages in vitro using reverse transcriptase-polymerase chain reaction. Results show that the interface membranes of septically and aseptically loosened prosthesis express more IRAK-M protein than control membranes from osteoarthritic patient and that IRAK-M mRNA-levels increase upon particle stimulation. These findings suggest that, the upregulation of IRAK-M in macrophages is involved in the local immunosuppression around implants, and may contribute to septic and aseptic implant loosening.

[Clinical evaluation of vacuum sealing drainage for treatment of deep infection after hip or knee replacement].

OBJECTIVE: To investigate the method and effectiveness of vacuum sealing drainage (VSD) combined with debridement for treatment of deep infection after hip or knee replacement. METHODS: Between September 2006 and May 2010, 13 cases of deep infection after joint replacement surgery were treated, including 5 males and 8 females with an average age of 62.5 years (range, 56-78 years). Infection occurred at 7 days to 1 year and 2 months (median, 14 days) after joint replacement surgery. The time from infection to admission was 8 days to 4 years and 6 months (median, 21 days). Purulent secretion with or without blood were observed in all patients; sinus formed in 5 cases; and unhealing of incision or drainage opening disunion were observed in 8 cases. The size of skin defect at secretion drainage or sinus opening site was 5 mm x 3 mm to 36 mm x 6 mm; the depth of drainage tunnel or sinus was 21-60 mm. The histopathological examination in 11 patients showed acute infection or chronic infection with acute onset in 10 cases, and tuberculosis in 1 case. In 6 cases of secretion culture, Staphylococcus aureus was isolated from 5 cases. After thorough debridement, wound irrigation was performed during the day and VSD during the night in 10 cases. VSD was merely performed in 3 cases. RESULTS: In 1 case after revision total hip arthroplasty, the wound bled profusely with VSD, then VSD stopped and associated with compression bandage, VSD proceeded again 3 days later with no heavy bleeding. All the patient were followed up 1 year to 4 years and 5 months (mean, 2 years and 11 months). Infection were controlled 7-75 days (mean, 43 days) after VSD in 10 cases. In these cases, prosthesis were reserved, no recurrent infection was observed, wound were healed, limb function were reserved. VSD was refused in 1 case because of hypersensitive of the pain at the vacuum site, infection control was failed and amputation at the thigh was proceeded. The effect was not evident in 1 case with tuberculosis infection, then the prosthesis was removed and arthrodesis was proceeded followed by complete union. In 1 case, infection was cured with VSD, recurrent infection happened after 9 months, antibiotic-impregnated cement spacer was used at end, and no recurrence was observed 1 year and 4 months later. CONCLUSION: VSD combined with debridement can drainage deep infection sufficiently, promote wound healing, reduce recurrent infection rate, maximize the possibility of prosthesis preservation.

[Preparation and biomechanics study of biological artificial knee joint prosthesis with stereo mesh surface in rabbit].

OBJECTIVE: To develop a kind of biological artificial knee joint prosthesis with stereo mesh surface for rabbit, to observe its function after being implanted into rabbit knee joint and to evaluate its biomechanical property. METHODS: Thirty adult New Zealand rabbits were randomized into experimental and control groups (n=15), total left knee arthroplasty was performed in both groups, no patella replacement was performed. Biological artificial knee joint prosthesis with stereo mesh surface was self-designed. The adjacent 4/5 surface of femur and tibia stem of the prosthesis was covered by stainless steel stereo mesh, the inner surface of femur condyles and tibia plateau was welded with two layers of stainless steel stereo mesh, then the prosthesis underwent biological fixation in the experimental group. Meanwhile, prosthesis having smooth marrow internal stem, femoral condyle and tibial plateau internal surface and sharing the same shape and size with the experimental group were prepared and fixed with bone cement in the control group. The postoperative general condition of animal was observed. At 1, 3 and 6 months after operation, the rabbits were killed for gross observation, X-ray examination was conducted to observe the fixation condition of prosthesis and healing condition, the range of motion (ROM) of knee joints was tested, biomechanics test was carried out and the maximum shear strength of prosthesis bone interface was calculated. RESULTS: In each group, there was 1 rabbit died and new one was added during the second experiment. The others survived till the end of the experiment and crawled normally 7 days after operation. For the excellent and good rate concerning the recovery of ROM of the knee joint at 1, 3 and 6 months after operation, the experimental group was 60%, 80% and 80%, respectively, and the control group was 60%, 80% and 60%, respectively, indicating there were no significant differences between two groups (P > 0.05). For the experimental group, the gross observation showed large quantities of bone reconstruction, X-ray films indicated the prosthesis fitted well, with solid fixation and without dislocation and loosening; while for the control group, the gross observation showed no bone reconstruction, X-ray films displayed the location of prosthesis was good, with solid fixation and without dislocation and loosening. Radiolucent zone around the femur prosthesis and stress shielding occurred 6 months after operation. For the maximum shear strength, the experimental group was less than the control group at 1 month after operation; and it was higher than the control group at 3 and 6 months after operation, indicating there were significant differences between two groups (P < 0.01). CONCLUSION: The fixation strength of the biological artificial knee joint prosthesis with stereo mesh surface is better than that of the bone cement prosthesis in rabbits at 3 and 6 months after operation.