[Comprehensive evaluation of soil quality of different land use types on the northeastern margin of the Qinghai-Tibet Plateau, China]. / 青藏高原东北缘不同土地利用类型土壤质量综合评价.

Soil quality evaluation is an important prerequisite for the rational soil resource utilization. We collected soil samples from forest (n=9), grassland (n=18) and cropland (n=38) in Tianzhu County, Gansu Province, which is located on the northeastern edge of the Qinghai-Tibet Plateau. Soil quality was evaluated based on thirteen soil physical and chemical indicators, including soil bulk density, field capacity, and organic matter. A minimum data set (MDS) was constructed using principal component analysis and correlation analysis to establish a soil qua-lity evaluation index (SQI) system, which was used in the soil quality evaluation for the three land-use types. The results showed that total porosity, capillary porosity, field capacity, capillary water capacity, saturated water content, organic matter, total nitrogen and available potassium content were significantly higher in forest than those in grassland and cropland. The SQI system of forest was based on field capacity, organic matter, total nitrogen, available nitrogen, and available potassium, and the SQI ranged between 0.329 to 0.678, with a mean value of 0.481. Grassland SQI system was based on field capacity and available nitrogen, with the SQI ranging between 0.302 to 0.703 and a mean value of 0.469. Cropland SQI system was based on capillary water capacity, non-capillary porosity, available nitrogen, available phosphorus, and available potassium, and the SQI ranged from 0.337 to 0.616 with a mean value of 0.462. The most important barriers to soil quality improvement in forest, grassland, and cropland were available potassium, field capacity, and capillary water capacity, respectively. The MDS-based SQI enabled an accurate evaluation of soil quality across different land-use types in the study area, which was best in forest followed by grassland and cropland. The evaluation results would provide important reference for sustainable soil management in the local area.

Spontaneous pseudoaneurysm of the posterior tibial artery successfully treated by open surgery: Case report and review of the literature.

RATIONALE: An extremely rare spontaneous pseudoaneurysm (PSA) of the posterior tibial artery (PTA) in a middle-aged male patient was cured by open surgery effectively. PATIENT CONCERNS: A 53-year-old man presented with the increasing swollen left shank for 1 day, with intermittent pain, pulselessness and pallor. He denied the history of trauma, infection, and other diseases. DIAGNOSES: Physical examination, past medical history, ankle brachial index, ultrasonography, computed tomographic angiography (CTA), 3-dimensional reconstruction image of the popliteal artery and its branches and histological examination of intraluminal thrombus and clots helped us diagnose the patient as spontaneous PSA of PTA. INTERVENTIONS: Our patient underwent excision of PSA and repair operation of PSA. OUTCOMES: The patient recovered well at 2-year follow-up. LESSONS: This rare case provides valuable insights for tissue repair and vascular surgery. Therapeutic methods should be in accordance with the best interest of patient. Open surgery is the effective treatment for spontaneous PSA of PTA.

Extracellular vesicle-carried microRNA-27b derived from mesenchymal stem cells accelerates cutaneous wound healing via E3 ubiquitin ligase ITCH.

Mesenchymal stem cells (MSCs) have been highlighted as promising candidate cells in relation to cutaneous wound healing. The current study aimed to investigate whether MSC-derived extracellular vesicles (EVs) could transfer microRNA-27b (miR-27b) to influence cutaneous wound healing. The miR-27b expression was examined in the established cutaneous wound mouse model, and its correlation with the wound healing rate was evaluated by Pearson's correlation analysis. The identified human umbilical cord MSC-derived EVs were co-cultured with human immortal keratinocyte line HaCaT and human skin fibroblasts (HSFs). The mice with cutaneous wound received injections of MSC-derived EVs. The effects of EVs or miR-27b loaded on wound healing and cellular functions were analysed via gain- and loss-of-function approaches in the co-culture system. Dual-luciferase reporter gene assay was employed to verify the relationship between miR-27b and Itchy E3 ubiquitin protein ligase (ITCH). Rescue experiments were conducted to investigate the underlying mechanisms associated with the ITCH/JUNB/inositol-requiring enzyme 1α (IRE1α) axis. miR-27b was down-regulated in the mouse model, with its expression found to be positively correlated with the wound healing rate. Abundant miR-27b was detected in the MSC-derived EVs, while EV-transferred miR-27b improved cutaneous wound healing in mice and improved proliferation and migration of HaCaT cells and HSFs in vitro. As a target of miR-27b, ITCH was found to repress cell proliferation and migration. ITCH enhanced the JUNB ubiquitination and degradation, ultimately inhibiting JUNB and IRE1α expressions and restraining wound healing. Collectively, MSC-derived EVs transferring miR-27b can promote cutaneous wound healing via ITCH/JUNB/IRE1α signalling, providing insight with clinical implications.

Marrubenol inhibits osteosarcoma cancer cell growth by inducing autophagic cell death and inhibiting cancer cell migration and invasion.

PURPOSE: The present study aimed at evaluating the anticancer activity of marrubenol against osteosarcoma cells along with evaluating its effects on autophagic cell death, reactive oxygen species (ROS) generation and cell migration and invasion tendency. METHODS: In this study the Saos-2 osteosarcoma cell line was used. Cell cytotoxicity effects were evaluated by MTT cell viability assay, while clonogenic assay assessed the effects on cancer cell colony formation. In vitro wound healing assay was used to evaluate the effects on cell migration. To confirm autophagy, we evaluated the expression of several autophagy-associated proteins Western blot assay along with transmission electron microscopy (TEM). RESULTS: The results indicated that the marrubenol exhibited an IC50 value of 45 µM and exerted its cytotoxic effects in a dose-dependent manner. Moreover, it was observed that the drug inhibited colony formation and induced autophagy dose-dependently. The underlying mechanism for the induction of autophagy was found to be ROS-mediated and significant inhibition of cell migration as well as cell invasion potential of osteosarcoma cells at the IC50 was observed. CONCLUSIONS: These results strongly indicate that marrubenol may be considered as a potent drug lead molecule for the treatment and management of osteosarcoma.

Multi-Level Assessment of Fracture Calluses in Rats Subjected to Low-Magnitude High-Frequency Vibration with Different Rest Periods.

The aim of this study was to investigate the influences of low-magnitude high-frequency vibration (LMHFV) with different rest period regimes (vibrational loading per day [with or without the loading divided into bouts]; or vibrational loading for 7 day followed by 7 day rest [with or without the loading divided into bouts]) on bone healing at multi-levels. Transverse fractures of rat bilateral tibias were established using a Kirschner wire inserted for fixation. The animals were randomly assigned to five groups (n = 7 for each group): four for vibrational groups by LMHFV with different rest period regimes and one for fractured model without mechanical loading. The macromechanical properties of the fractured tibias and the nanomechanical properties of the calluses were investigated through three-point bending and nanoindentation tests, respectively. Atomic force microscopy (AFM) was performed to analyze the nanostructure of the calluses. Micro-computed tomography (micro-CT) scanning was conducted to evaluate the microarchitecture of the calluses. The serum concentration of osteocalcin (OG) and tartrate-resistant acid phosphatase 5b (TRAP5b) were measured to assess the bone formation and resorption rates, respectively. Significantly higher values of failure load and elastic modulus were observed in DL (vibrational loading for 15 min per day) and DLR (vibrational loading per day in which three bouts of 5 min of vibration were separated by 4 h) than FBC (fractured model without mechanical loading) at macro-level (P < 0.05). The results of nanoindentation test showed the highest values of indentation modulus and hardness in DLR (significantly higher than FBC; P < 0.05); besides, higher value of hardness was also observed in DL (significantly higher than FBC; P < 0.05). Though AFM imaging showed no significant differences in grain sizes between the vibrational groups and FBC, roughness of DLR showed the highest value, i.e. it was significantly higher than that in FBC (P < 0.05). For microarchitectural parameters obtained from micro-CT imaging, tissue mineral density (TMD) of DLR and VL7 (vibrational loading for 7 day followed by a 7-day rest, 15 min per day during vibrational periods) were significantly higher than that in FBC (P < 0.05), but no significant differences in other parameters were observed between vibrational groups and FBC. There were no significant differences of OG between vibrational groups and FBC; however, FBC showed significantly higher TRAP5b concentration than all vibrational groups (P < 0.05). The results show that LMHFV with different rest period regimes not only altered the macro- and nano-level bone mechanical properties but also influenced the TMD of calluses and nano-level spatial arrangement (roughness) significantly. The most significant effect of LMHFV with different rest period regimes was observed in DLR, which indicated that both osteogenic accumulation and cellular resensitization can be satisfied under this regimen. Hence, the DLR group demonstrated a great potential in clinical applications.

Initial Stability of Subtrochanteric Oblique Osteotomy in Uncemented Total Hip Arthroplasty: A Preliminary Finite Element Study.

BACKGROUND: Subtrochanteric oblique osteotomy (SOO) has been widely used to reconstruct highly dislocated hips in uncemented total hip arthroplasty. The occurrence of complications can be attributed to the instability of the osteotomy region. The aim of this study was to evaluate the initial stability of SOO in uncemented total hip arthroplasty. MATERIAL AND METHODS: A 3-dimensional finite element femur-stem model was created, and a virtual SOO was performed at 4 oblique angles: 30°, 45°, 60°, and 90°. The von Mises stress distribution in the femur-stem complex and the displacement under different oblique angles were evaluated in the SOO models, in comparison with that of the intact model. RESULTS: The study demonstrated that the distal fragment of the femur bore more stresses than the proximal fragment, and the maximum stress was concentrated in the femoral neck and the cortical bone, which contacted with the distal end of the stem. SOO increased the stress of both the femur and the stem, and fractures may occur in the stress concentration sites. Additionally, comparing the displacement at different oblique angles, the lateral region was larger than that of the medial region on the subtrochanteric osteotomy plane. The minimum micromotion on the osteotomy plane was obtained when the oblique angle was 45°. CONCLUSIONS: The fit and fill of the distal fragment of the femur and the stem is essential for the stability of the subtrochanteric osteotomy region. The optimal oblique angle for SOO appears to be 45°.

Multi-level femoral morphology and mechanical properties of rats of different ages.

A macro-micro-nano-multi-level study was conducted to explore age-related structural and mechanical properties of bone, as well as the effects of aging on bone properties. A total of 70 male Wistar rats were used, ranging in the ages of 1, 3, 5, 7, 9, 11, 14, 15, 16, and 17 months (n = 7/age group). After micro-computed tomography (CT) scanning, longitudinal cortical bone specimens with a length of 5mm were cut along the femoral shaft axis from left femur shafts for mechanical testing, and the cross-sectional areas were measured. The macro-mechanical properties obtained in mechanical testing and microarchitecture parameters measured by micro-CT were significantly correlated with the animal age (r(2) = 0.96, p < 0.001). Scanning electron microscopy was used for detecting the microarchitecture features of the fractured surfaces, which exhibited age-related plate-fibrous-mixed fibrous-plate texture, resulting in changes in macro-mechanical properties (r(2) > 0.90, p < 0.001). The mineral phase of the left femoral shaft and head was analyzed by atomic force microscopy. Longitudinal and transverse trabecular bone tissues, as well as longitudinal cortical bone tissue, were used for nanoindentation test, and the chemical composition was evaluated by quantitative chemical analyses. The correlations between mineral content and bone material properties (i.e., elastic properties of the bone tissue and size and roughness of bone mineral grains) were highly significant (r > 0.95, p < 0.001). Multi-level femur morphology, mechanical property, and mineral content were significantly correlated with the animal age. The correlations between bone mineral content and bone material morphological and mechanical properties may partly explain the increase in bone fragility with aging, which will provide a theoretical basis for the investigation of age-related bone properties in clinics.

Synergistic effect of celecoxib in tumor necrosis factor­related apoptosis­inducing ligand treatment in osteosarcoma cells.

Tumor necrosis factor-related apoptosis­inducing ligand (TRAIL) is under clinical development as a cancer therapeutic as it has been shown to induce apoptosis in numerous types of cancer cells without significant toxicity towards normal cells. However, the majority of osteosarcoma (OS) tumors are resistant to TRAIL. Thus, the development of cancer therapeutics that overcome TRAIL resistance is required. In the present study, celecoxib (CXB), a non-steroidal anti­inflammatory drug, was administered in combination with TRAIL to induce cell apoptosis and the doses of the two drugs were simultaneously reduced. The effects of this combination treatment were examined in MG-63 human OS cancer cell lines in culture. Assays of proliferation, apoptosis and tumor growth were performed, along with analysis of the proteins involved. The results revealed that CXB sensitized TRAIL-resistant MG-63 OS cells to TRAIL­induced apoptosis through downregulation of cellular B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein, caspase-8 and caspase-3. Furthermore, combination treatment reduced tumor growth in a nude rat model. In conclusion, the experimental results provided evidence that the combined administration of CXB and TRAIL is potentially a novel treatment method of OS tumors.

Association between CTLA-4 genetic polymorphisms and susceptibility to osteosarcoma in Chinese Han population.

Osteosarcoma (OS) is the most common malignant primary bone tumor in the world. The cytotoxic T-lymphocyte antigen-4 gene (CTLA-4) is an important candidate gene for influencing the development of OS. This study aimed to investigate the potential association of CTLA-4 genetic polymorphisms with OS risk in Chinese Han population. A total of 415 OS patients and 431 healthy controls were enrolled in this study. The created restriction site-polymerase chain reaction (CRS-PCR) and DNA sequencing methods were used to detect the genotyping of CTLA-4 c.75G[C and c.326G[A genetic polymorphisms. We observed that the genotypes/alleles of c.75G[C and c.326G[A genetic polymorphisms were statistically associated with the increased risk of OS (for c.75G[C, CC versus (vs.) GG: OR 1.72, 95% CI 1.09­2.74; C vs. G: OR 1.30, 95% CI 1.06­1.60; for c.326G[A, AA vs. GG: OR 2.12, 95% CI 1.31­3.42; A vs. G: OR 1.31, 95% CI 1.07­1.61). The allele-C/genotype-CC of c.75G[C and allele-A/genotype-AA of c.326G[A may contribute to OS susceptibility. These data indicate that CTLA-4 genetic polymorphisms are potentially related to OS risk in Chinese Han population, and might be used as molecular markers for evaluating the risk of OS.

Association analysis between genetic variants of MDM2 gene and osteosarcoma susceptibility in Chinese.

Osteosarcoma (OS) is the most common pediatric bone malignancy worldwide. The MDM2 gene is an important candidate gene for influencing the susceptibility to OS. The objective of this study aimed to detect the potential association between MDM2 genetic variants and OS susceptibility in Chinese Han population. We recruited 415 OS patients and 431 cancer-free controls in this case-control study. The c.44C>T and c.1002T>C genetic variants in MDM2 gene were investigated using created restriction site-polymerase chain reaction (CRS-PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP), respectively. We found that the genotypes/alleles of c.44C>T and c.1002T>C were statistically associated with the increased risk of OS (for c.44C>T, TT versus (vs.) CC: OR = 2.43, 95% CI 1.49-3.95, p < 0.001; T vs. C: OR = 1.36, 95% CI 1.11-1.67, p = 0.003; for c.1002T>C, CC vs. TT: OR = 2.38, 95% CI 1.37-4.13, p = 0.002; C vs. T: OR = 1.27, 95% CI 1.02-1.56, p = 0.030). The T allele and TT genotype of c.44C>T and C allele and CC genotype of c.1002T>C could be increased risk factors for the susceptibility to OS. Results from this study suggest that MDM2 genetic variants are potentially related to OS susceptibility in Chinese Han population, and might be used as molecular markers for assessing OS susceptibility.

High-frequency and low-magnitude whole body vibration with rest days is more effective in improving skeletal micro-morphology and biomechanical properties in ovariectomised rodents.

We explored the optimal regime in preventing or treating bone loss, using ovariectomised rodents loaded by mechanical stimuli with rest days during the loading cycle. Eighty-four Sprague-Dawley rats, aged 6 months, were randomly divided into 7 groups after bilateral ovariectomy. Mechanical vibration with 1-day rest (ML1R), with 3-day rest (ML3R), with 5-day rest (ML5R), with 7-day rest (ML7R), daily loading (DL), comparing the ovariectomised group (OVX) with baseline (BCL) measurements. After a recovery of one week, all the rodents were loaded daily by whole body vibration at 35 Hz and 0.25 g for 15 minutes. Eight weeks later, a three-point bending test of the radius and micro-CT scanning of the femoral head were performed after animal sacrifice. Large improvements in biomechanical properties occurred in all the experimental groups for failure load, elastic modulus and deflection, while a significantly enhanced efficacy was detected in ML7R compared with daily loading (p<0.05). In micro-CT scanning, bone volume fraction, trabecular thickness, number and separation were improved by the regime in all experimental groups, while ML7R showed a significant improvement over daily loading (p<0.05). Early bone loss in human subjects may be improved by high-frequency and low-magnitude whole body vibration with rest days or daily stimuli. Mechanical stimulus with a 7-day rest was more effective in improving biomechanical properties and micro-morphology compared with daily loading. This may have clinical implications in relation to the prevention and treatment of hip fractures, and in postoperative management following hip arthroplasty.

Causes of death after hip fracture in senile patients.

Hip trauma has been a leading cause of death in senile patients for more than a centenary. Although the mortality decreased due to the advanced technique in medication, surgery and nursing, the increasing mortality should not be neglected in elders after orthopedic operation nowadays. Many factors are considered to influence the causes of death after trauma, such as age, gender, personal customs, comorbidities, types of fracture, timing of surgery, procedure, anesthesia, complications, medical treatment, activity of daily living, or even marriage status. This article reviews these causes from the aspects of patient's own factors, iatrogenic factors, medical treatment and other factors and provides some clues for further clinical application according to the recent foreign and domestic researches. According to the present research, it is essential for surgeons to perform a comprehensive estimation for patients suffering from hip trauma.

Postoperative mortality and morbidity in octogenarians and nonagenarians with hip fracture: an analysis of perioperative risk factors.

OBJECTIVE: To evaluate the role of high risk factors in octogenarians and nonagenarians with hip trauma, which may lead to excessive mortality and morbi- dity postoperatively. METHODS: Fifty-four octogenarians and nonagenarians patients were enrolled in the study, receiving surgical repair of hip fracture in our hospital from January 2006 to January 2010. High risk factors were recorded preoperatively in detail. Complications and survival state were followed up by telephone for 2 years postoperatively. All the data were analyzed by Chi-square test with SPSS 13.0. RESULTS: Twenty-six males (48.1%), aged from 80 to 94 years with a mean age of 84.2 years, and twenty-eight females (51.9%), aged from 80 to 95 years with a mean age of 83.4 years, were presented in the cohort study. The hip traumas were caused by daily slight injuries (52 cases) and car accidents (2 cases), respectively. Twenty-eight patients (51.9%) with femoral neck fracture while 26 patients (48.1%) with intertrochanteric fracture were diagnosed through an anterior-posterior pelvic radiophotograph. In this series, 39 patients (72.2%) suffered from one or more comorbidities preoperatively. The morbidity was 48.1% and the major cause was urinary tract infection, while a significant difference was noted between females and males. The mortality was 20.4% with a predominant cause of acute renal failure. CONCLUSIONS: The gender should be considered as a critical high risk factor in octogenarians and nonagenarians with hip trauma postoperatively. Females are more likely to suffer complications postoperatively, which is especially obvious in senile patients over 80 years (P less than 0.05). Urinary tract infection is the most frequent complication after hip surgery, followed by low limb embolism and malnutrition. The mortality is dramatically greater in patients over 80 years old than those below, and major causes are acute renal failure, multiple organ dysfunction syndrome and mental deterioration. Multidisciplinary consultations and mental assessment are encouraged in patients over 80 years old after hip trauma and surgery. Hip fractures in octogenarians and nonagenarians deserve special attention because of their advanced age and comorbidities.

Relationship between surgical time and postoperative complications in senile patients with hip fractures.

OBJECTIVE: To elucidate the relationship between surgical time and postoperative complications in senile patients with hip fractures, and try to find out other factors which are related to these complications. METHODS: Sixty-two patients, 28 males aged from 65 to 72 years with a mean age of 76.3 years and 34 females aged from 65 to 95 years with a mean age of 78.1 years, who had undergone orthopedic surgery because of hip fractures, were enrolled in a retrospective cohort study. The surgical time and pattern, the type of fracture, preoperative comorbidities, American Society of Anesthesiologists (ASA) score and the volume of blood transfusion during operation were obtained from these patients who were followed up by telephone calls for postoperative complications. All the patients were followed up at least for 1 year and were divided into subgroups according to their clinical characteristics and the results were analyzed by the Statistical Analysis System software. RESULTS: There was no significant difference in the morbidity of postoperative complications with the gender, age, surgical time and pattern, or ASA score. There was significant difference in the morbidity of postoperative complications related to preoperative comorbidities and the volume of blood transfusion. There was a significant causality between preoperative comorbidities and postoperative complications. The morbidity of postoperative complications was 1.651 times higher in patients with preoperative comorbidities than those without. CONCLUSIONS: There is no relationship between the surgical time and postoperative complications in senile patients who received surgery for hip fracture within 1 year. No correlation is found between the postoperative complications and gender, age, type of fracture, surgical pattern, ASA score and the volume of blood transfusion. Preoperative comorbidities are an independent predictor for postoperative complications.