Three-dimensional finite element analysis of intramedullary nail with different materials in the treatment of intertrochanteric fractures

Intramedullary nails are the common treatment options for femoral intertrochanteric fractures. However, aseptic loosening is considered to be one of the primary forms of failure that can be caused by the stress shielding between the bone and implants. The matching in mechanical properties of implant and bone is a key issue to prevent this failure. Polyetheretherketone (PEEK) and Function-graded (FG) materials are widely used in clinical because of their excellent mechanical properties. In this study, to investigate the biomechanical behaviors of intramedullary nails made of Ti-6Al-4V alloy, Stainless Steel (SS), PEEK and two FG materials, three-dimensional finite element models of intertrochanteric fracture femur with intramedullary nail were constructed with ABAQUS. The maximum von Mises stress on the femoral fracture surface fixed by PEEK intramedullary nail was the largest, followed by FG intramedullary nail, which help stimulate bone growth and subsequently reduce fracture healing time. Compared with traditional metal intramedullary nails, PEEK and FG implants might increase von Mises stress along the same path in the proximal femur. The results showed that PEEK and FG intramedullary nails obviously changed the stress distributions in the bone and reduced stress shielding. This finding indicated that PEEK and FG intramedullary nails have the potential to become alternatives to the conventional metal intramedullary nails.     

Exploring a 7-gene prognostic model based on ferroptosis for efficiently guiding immunotherapy in melanoma patients

PurposeAlthough skin cutaneous melanoma (SKCM) is a relatively immunotherapy-sensitive tumor type, there is still a certain fraction that benefits less from treatment. Ferroptosis has been demonstrated to modulate tumor progression in many cancer types. This study focused on ferroptosis-related genes to construct a prognostic model for SKCM patients.Materials and methodsGene expression profiles of SKCM samples were obtained from public databases. Unsupervised consensus clustering was used to determine molecular subtypes related to ferroptosis. Least absolute shrinkage and selection operator (LASSO) and stepwise Akaike information criterion (stepAIC) were applied to construct a prognostic model based on differentially expressed genes between two molecular subtypes.ResultsC1 and C2 subtypes were identified with differential prognosis and immune infiltration. A 7-gene prognostic model was constructed to classify samples into high-FPRS and low-FPRS groups. Low-FPRS group with favorable prognosis had higher immune infiltration and more enriched immune-related pathways than the high-FPRS group. The two groups showed distinct sensitivity to immunotherapy, with the low-FPRS group predicted to have more positive response to immunotherapy than the high-FPRS group. A nomogram based on the FPRS score and clinical features was built for more convenient use.ConclusionsThe critical role of ferroptosis involved in SKCM development was further validated in this study. The prognostic model was efficient and stable to be applied in clinical conditions to support clinicians in determining personalized therapy for SKCM patients especially those with metastasis.     

Sex difference in the association between surrogate markers of insulin resistance and arterial stiffness

AimsTo investigate the predictive capability of insulin resistance surrogate markers for insulin resistance and arterial stiffness based on sex.MethodsWe assessed the association of triglyceride glucose (TyG) index, triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C), visceral adiposity index (VAI), and lipid accumulation product (LAP) with homeostasis model assessment-insulin resistance (HOMA-IR) and brachial–ankle pulse wave velocity (baPWV) in both sexes.ResultsA total of 1720 men and 1098 women were evaluated. HOMA-IR showed good correlation with the TyG index (men: r = 0.47, women: r = 0.45), TG/HDL-C (men: r = 0.45, women: r = 0.41), VAI (men: r = 0.51, women: r = 0.48), and LAP (men: r = 0.55, women r = 0.49) (all p-values < 0.001). These markers positively correlated with increased baPWV in both sexes. The standardized partial regression coefficients were 0.11 and 0.14 for the TyG index, 0.13 and 0.16 for TG/HDL-C, 0.14 and 0.19 for VAI, and 0.12 and 0.17 for LAP in men and women, respectively (all p-values < 0.01; all p-values for sex interaction < 0.05).ConclusionsAll insulin surrogate markers showed good correlation with HOMA-IR in both sexes. These indices were also associated with increased baPWV and the associations were stronger in women than in men.     

Delirium Development After Lung Transplantation: An Intraoperative Assessment

BackgroundThis study aimed to evaluate the relationship between intraoperative hemodynamic and laboratory parameters with postoperative delirium development after lung transplantation.MethodsA total of 77 patients who underwent lung transplantation in a single center were included in the study. Demographic and clinical data recorded at critical intraoperative stages (after induction [T1], after bilateral lungs are dissected [T2], while the patient is ventilated for 1 lung [T3], while the unilateral transplanted lung is ventilated [T4], while bilateral transplanted lungs are ventilated [T5], and after the thorax is closed [T6]), postoperative complications, mechanical ventilation duration, intensive care, and hospitalization durations and mortality rates were recorded.ResultsA total of 83.1% of the 77 patients were male, and the mean (SD) age was 47.56 (12.95) years. The mean body mass index (calculated as weight in kilograms divided by height in meters squared) was 23.30 (3.99), and the median Charles Comorbidity Index (CCI) was 1. The diagnosis of 36.4% of the patients was chronic obstructive pulmonary disease. Delirium was seen in 51.9% of the patients. Age, CCI, intraoperative mean arterial pressure changes, lactate levels, mechanical ventilation duration, and hospital stay were all associated with delirium development.ConclusionAge, CCI, duration of mechanical ventilation, and hospital stay were independent predictors of postoperative delirium development. We believe that our study will be a guide for future prospective randomized controlled studies.     

Prediction of early recurrence of hepatocellular carcinoma after liver transplantation based on computed tomography radiomics nomogram

BackgroundEarly recurrence results in poor prognosis of patients with hepatocellular carcinoma (HCC) after liver transplantation (LT). This study aimed to explore the value of computed tomography (CT)-based radiomics nomogram in predicting early recurrence of patients with HCC after LT.MethodsA cohort of 151 patients with HCC who underwent LT between December 2013 and July 2019 were retrospectively enrolled. A total of 1218 features were extracted from enhanced CT images. The least absolute shrinkage and selection operator algorithm (LASSO) logistic regression was used for dimension reduction and radiomics signature building. The clinical model was constructed after the analysis of clinical factors, and the nomogram was constructed by introducing the radiomics signature into the clinical model. The predictive performance and clinical usefulness of the three models were evaluated using receiver operating characteristic (ROC) curve analysis and decision curve analysis (DCA), respectively. Calibration curves were plotted to assess the calibration of the nomogram.ResultsThere were significant differences in radiomics signature among early recurrence patients and non-early recurrence patients in the training cohort (P < 0.001) and validation cohort (P < 0.001). The nomogram showed the best predictive performance, with the largest area under the ROC curve in the training (0.882) and validation (0.917) cohorts. Hosmer-Lemeshow testing confirmed that the nomogram showed good calibration in the training (P = 0.138) and validation (P = 0.396) cohorts. DCA showed if the threshold probability is within 0.06-1, the nomogram had better clinical usefulness than the clinical model.ConclusionsOur CT-based radiomics nomogram can preoperatively predict the risk of early recurrence in patients with HCC after LT.     

Comparative proteomics reveals essential mechanisms for osmotolerance in Gluconacetobacter diazotrophicus

Plant growth-promoting bacteria are a promising alternative to improve agricultural sustainability. Gluconacetobacter diazotrophicus is an osmotolerant bacterium able to colonize several plant species, including sugarcane, coffee, and rice. Despite its biotechnological potential, the mechanisms controlling such osmotolerance remain unclear. The present study investigated the key mechanisms of resistance to osmotic stress in G. diazotrophicus. The molecular pathways regulated by the stress were investigated by comparative proteomics, and proteins essential for resistance were identified by knock-out mutagenesis. Proteomics analysis led to identify regulatory pathways for osmotic adjustment, de novo saturated fatty acids biosynthesis, and uptake of nutrients. The mutagenesis analysis showed that the lack of AccC protein, an essential component of de novo fatty acid biosynthesis, severely affected G. diazotrophicus resistance to osmotic stress. Additionally, knock-out mutants for nutrients uptake (Δtbdr and ΔoprB) and compatible solutes synthesis (ΔmtlK and ΔotsA) became more sensitive to osmotic stress. Together, our results identified specific genes and mechanisms regulated by osmotic stress in an osmotolerant bacterium, shedding light on the essential role of cell envelope and extracytoplasmic proteins for osmotolerance.     

CD40-mediated immune cell activation enhances response to anti-PD-1 in murine intrahepatic cholangiocarcinoma

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