Hint from an Enzymatic Reaction: Superoxide Dismutase Models Efficiently Suppress Colorectal Cancer Cell Proliferation.

Superoxide dismutases (SODs) are essential antioxidant enzymes that prevent massive superoxide radical production and thus protect cells from damage induced by free radicals. However, this concept has rarely been applied to directly impede the function of driver oncogenes, thus far. Here, leveraging efforts from SOD model complexes, we report the novel finding of biomimetic copper complexes that efficiently scavenge intracellularly generated free radicals and, thereby, directly access the core consequence of colorectal cancer suppression. We conceived four structurally different SOD-mimicking copper complexes that showed distinct disproportionation reaction rates of intracellular superoxide radical anions. By replenishing SOD models, we observed a dramatic reduction of intracellular reactive oxygen species (ROS) and adenine 5'-triphosphate (ATP) concentrations that led to cell cycle arrest at the G2/M stage and induced apoptosis in vitro and in vivo. Our results showcase how nature-mimicking models can be designed and fine-tuned to serve as a viable chemotherapeutic strategy for cancer treatment.

SRSF6 Regulates the Alternative Splicing of the Apoptotic Fas Gene by Targeting a Novel RNA Sequence.

Alternative splicing (AS) is a procedure during gene expression that allows the production of multiple mRNAs from a single gene, leading to a larger number of proteins with various functions. The alternative splicing (AS) of Fas (Apo-1/CD95) pre-mRNA can generate membrane-bound or soluble isoforms with pro-apoptotic and anti-apoptotic functions. SRSF6, a member of the Serine/Arginine-rich protein family, plays essential roles in both constitutive and alternative splicing. Here, we identified SRSF6 as an important regulatory protein in Fas AS. The cassette exon inclusion of Fas was decreased by SRSF6-targeting shRNA treatment, but increased by SRSF6 overexpression. The deletion and substitution mutagenesis of the Fas minigene demonstrated that the UGCCAA sequence in the cassette exon of the Fas gene causes the functional disruption of SRSF6, indicating that these sequences are essential for SRSF6 function in Fas splicing. In addition, biotin-labeled RNA-pulldown and immunoblotting analysis showed that SRSF6 interacted with these RNA sequences. Mutagenesis in the splice-site strength alteration demonstrated that the 5' splice-site, but not the 3' splice-site, was required for the SRSF6 regulation of Fas pre-mRNA. In addition, a large-scale RNA-seq analysis using GTEX and TCGA indicated that while SRSF6 expression was correlated with Fas expression in normal tissues, the correlation was disrupted in tumors. Furthermore, high SRSF6 expression was linked to the high expression of pro-apoptotic and immune activation genes. Therefore, we identified a novel RNA target with 5' splice-site dependence of SRSF6 in Fas pre-mRNA splicing, and a correlation between SRSF6 and Fas expression.

Accurate application of a precontoured-locking plate for proximal humeral fractures in Asians: a cadaveric study.

OBJECTIVES: The purpose of this study was to identify the optimal position for a precontoured-locking plating (PHILOS(®)) of the proximal humerus in Asians in terms of conformity and to determine the prevalence of screw exits in the position of the highest conformity. METHODS: Twenty adult humeri and 14 cadaveric shoulders were included in this study. After placing the precontoured plate in the well-fitted position on the humerus, we measured the distance between the upper margin of the plate and the tip of greater tuberosity (GT) (distance A) and the distance between the anterior margin of the plate and lateral border of the bicipital groove (BG) (distance B). The prevalence of K-wire exits was assessed. In the 14 cadaver shoulders, the mutual relation between the most inferior locking sleeve of the optimally positioned plate and the axillary nerve was evaluated to assess the potential for axillary nerve injury. RESULTS: The precontoured plate was well-fitted and remained in a relatively constant position in all specimens. Distance A was an average of 3.6 mm (range 1.4-5.5 mm), and distance B was an average of 2.5 mm (range 0-4.6 mm). The K wire closest to the BG pierced it in four cases (20 %), and most inferior K wires exited at an average distance of 3.8 mm (range 1.6-9.0 mm) from the inferior articular margin of the humeral head. Regarding involvement of the BG, articular width was the only significant variable in the logistic regression model, with an odds' ratio of 0.610. The axillary nerve was located at an average vertical distance of 59.7 mm (range 51.8-66.9 mm) from the tip of the GT in a vertically neutral position. The results did not differ between the left and right sides (t = 0.326, p = 0.755). Although the axillary nerve was slightly inferior to the most inferior locking holes of the proximal humerus, it was located in the path of their locking sleeves on the deltoid muscle. CONCLUSION: The optimal position for the highest conformity led to ideal fixation of the proximal humerus and inferomedial support screw in Asians. However, the precontoured plate sometimes had screw exits that involved the BG, and articular width had a large impact on involvement of the BG. If locking sleeves for the most inferior holes were introduced on the deltoid muscle in a neutral position, there was high potential for injury to the axillary nerve in Koreans.

Inflammatory cytokines are overexpressed in the subacromial bursa of frozen shoulder.

BACKGROUND: Frozen shoulder is a debilitating condition characterized by gradual loss of glenohumeral motion with chronic inflammation and capsular fibrosis. Yet its pathogenesis remains largely unknown. We hypothesized that the subacromial bursa may be responsible for the pathogenesis of frozen shoulder by producing inflammatory cytokines. MATERIALS AND METHODS: We obtained joint capsules and subacromial bursae from 14 patients with idiopathic frozen shoulder and from 7 control subjects to determine the expression levels of interleukin (IL) 1α, IL-1ß, IL-6, tumor necrosis factor α (TNF-α), cyclooxygenase (COX) 1, and COX-2 by real-time reverse transcriptase-polymerase chain reaction, immunohistochemistry, and enzyme-linked immunosorbent assay. RESULTS: IL-1α, IL-1ß, TNF-α, COX-1, and COX-2 were expressed at significantly high levels in the joint capsules of the frozen shoulder group compared with those of the control group. Intriguingly, IL-1α, TNF-α, and COX-2 were also expressed at significantly high levels in the subacromial bursae of the frozen shoulder group compared with those of the control group. Immunohistochemical analysis showed increased expression of COX-2 in both the joint capsules and subacromial bursae of the frozen shoulder group. CONCLUSIONS: These findings imply that elevated levels of inflammatory cytokines in the subacromial bursa may be associated with the pathogenesis of inflammation evolving into fibrosis.

Use of intramedullary nonvascularized fibular graft with external fixation for revisional Charcot ankle fusion: a case report.

We describe a case of Charcot ankle arthropathy in a 43-year-old male patient who underwent revision surgery for tibiotalocalcaneal arthrodesis with a retrograde intramedullary nonvascularized fibular graft. After 3 months of postoperative stabilization with a ring external fixator, successful radiographic union was identified. The findings obtained at 33 months postoperatively showed maintenance of solid fusion and restoration of hindfoot alignment without any complications.

Revision total knee arthroplasty with a cemented posterior stabilized, condylar constrained or fully constrained prosthesis: a minimum 2-year follow-up analysis.

BACKGROUND: The clinical and radiological outcomes of revision total knee arthroplasty with a cemented posterior stabilized (PS), condylar constrained knee (CCK) or a fully constrained rotating hinge knee (RHK) prosthesis were evaluated. METHODS: This study reviewed the clinical and radiological results of 36 revision total knee arthroplasties with a cemented PS, CCK, and RHK prosthesis in 8, 25, and 13 cases, respectively, performed between 1998 and 2006. The mean follow-up period was 30 months (range, 24 to 100 months). The reason for the revision was aseptic loosening of one or both components in 15, an infected total knee in 18 and a periprosthetic fracture in 3 knees. The average age of the patients at the time of the revision was 65 years (range, 58 to 83 years). The original diagnosis for all primary total knee arthroplasties was osteoarthritis except for one case of a Charcot joint. All revision prostheses were fixed with cement. The bone deficiencies were grafted with a cancellous allograft in the contained defect and cortical allograft fixed with a plate and screws in the noncontained defect. A medial gastrocnemius flap was needed to cover the wound dehiscence in 6 of the 18 infected cases. RESULTS: The mean Knee Society knee score improved from 28 (range, 5 to 43) to 83 (range, 55 to 94), (p < 0.001) and the mean Knee Society function score improved from 42 (range, 10 to 66) to 82 (range, 60 to 95), (p < 0.001) at the final follow-up. Good or excellent outcomes were obtained in 82% of knees. There were 5 complications (an extensor mechanism rupture in 3 and recurrence of infection in 2 cases). Three cases of an extensor mechanism defect (two ruptures of ligamentum patellae and one patellectomy) were managed by the RHK prosthesis to provide locking stability in the heel strike and push off phases, and two cases of recurrent infection used an antibiotic impregnated cement spacer. The radiological tibiofemoral alignment improved from 1.7 degrees varus to 3.0 degrees valgus in average. Radiolucent lines were observed in 18% of the knees without progressive osteolysis. CONCLUSIONS: Revision total knee requires a more constrained prosthesis than primary total knee arthroplasty because of the ligamentous instability and bony defect. This short to midterm follow-up analysis demonstrated that a well planned and precisely executed revision can reduce pain and improve the knee function significantly. Infected cases showed as good a result as those with aseptic loosening through the use of antibiotics-impregnated cement beads and proper soft tissue coverage with a medial gastrocnemius flap.

Restoration of the center of rotation in revision total hip arthroplasty.

We measured the change of the center of hip rotation after the revision of acetabular loosening using an acetabular reconstruction ring and an impaction allogenic bone grafting. Thirty-five revision total hip arthroplasties were performed. The average follow-up was 3.8 years. Horizontal distance was changed from 34.01±10 mm preoperatively to 41.07±6 mm at the latest follow-up. Vertical distance was changed from 32.06±9 mm preoperatively to 20.21±7 mm at the latest follow-up. The Harris hip score was improved from an average of 47 in the preoperative period to 86 at the final follow-up. The restoration of the anatomical hip center has shown to be favorable in terms of functional and radiologic evaluation in total hip revision.

Comparison of internal bone transport and vascularized fibular grafting for femoral bone defects.

OBJECTIVE: To compare results between vascularized fibular grafting and internal bone transport for large bone defects of the femur. DESIGN: Retrospective review of patients. SETTING: University teaching hospitals. PATIENTS: This study included 37 patients with femoral bone loss: 20 patients were treated with internal bone transport and seventeen patients were treated with vascularized fibular grafting. MAIN OUTCOME MEASUREMENTS: The outcomes investigated were external fixation time, external fixation index, bone results (union, infection, deformity, leg length discrepancy), and functional results. RESULTS: The mean amount of filled defect was 8.4 cm with internal bone transport and 8.9 cm with vascularized fibular grafting. The external fixation index was 1.4 months/cm with internal bone transport and 1 month/cm with vascularized fibular grafting. The bone results and functional results of the internal bone transport were excellent in 65% and 0%, good in 5% and 45%, fair in 5% and 40%, poor in 25% and 15%, respectively, whereas those of the vascularized fibular grafting were excellent in 35% and 0%, good in 25% and 47%, fair in 5% and 35%, and poor in 35% and 18%. CONCLUSION: With vascularized fibular grafting, careful monitoring of circulation and early intervention surgery is necessary to avoid vascular failure. With internal bone transport, repeated radical debridement until control of infection is achieved, bone grafting at the docking site for early union, and avoiding stress fracture are recommended to improve bone results.

Spontaneous bone regeneration in surgically induced bone defects in young rabbits.

Defects of the femoral shaft (15%, 20%, 25%, and 30% of the femoral length) with intact periosteum were made in young rabbits to investigate differences in union time. The mean union time was 7.3, 7.1, 7.4, and 7.0 weeks, respectively and there was no significant difference ( >0.05) between the groups. The mean healing indices were 6.7, 4.6, 3.9, and 3.1 weeks/cm, respectively and these were significantly different ( <0.05) between the 15% bone defect group and the other bone defect groups. These results suggested that union time was not affected by the amount of bone defect. Femoral lengthening of 20% was performed to compare the quality of callus with those of the femoral defect of 20%. The mean healing indices of defect and lengthening were 4.6 and 5.7, respectively and the difference was significant ( = 0.004). The callus stiffness of femoral defect was higher ( = 0.02) than that after femoral lengthening whereas the bone mineral density of the callus showed no significant difference ( = 0.37) between two groups. The method of filling bone defect with callus generated from the intact periosteum may be a new therapeutic option for the reconstruction of large bone defects in children when other treatments are not available.