Orthopedics research output from China, USA, UK, Japan, Germany and France: A 10-year survey of the literature

BACKGROUND

In the past decade, researchers have made great progress in the field of Orthopedics. However, the research status of different countries is unclear. To summarize the number of published articles, we assessed the cumulative impact factors in top orthopedic journals. The aims of the study were to measure: 1) the quality and quantity of publications in orthopedics-related journals from China and other five counties, 2) the trend of the number of publications in orthopedics-related journals.

METHODS

The related journals were selected based on the 2014 scientific citation index (SCI) and articles were searched based on the PubMed database. To assess the quantity and quality of research output, the number of publications including clinical trials, randomized controlled trials, meta-analyses, case reports, reviews, citations, impact factors, number of articles in the top 10 journals and most popular journals were recorded.

RESULTS

A total of 143,138 orthopedics articles were published from 2005 to 2014. The USA accounts for 24.9% (35,763/143,138) of the publications, followed by UK (7878/143,138 (5.5%)), Japan (7133/143,138 (5.0%)), Germany (5942/143,138 (4.2%)), China (4143/143,138 (2.9%)) and France (2748/143,138 (1.9%)). The ranking for accumulated impact factors as follows: USA, UK, Japan, Germany, France and China. The mean impact factor's order is USA, China, Germany, Japan, France, UK, and interestingly the mean impact factors in Japan is similar to the Germany in 2005-2014. The USA had the highest percentage of articles in the top 10 journals, while China owns the least. The USA had the highest number of average citations, while Japan had lowest number of average citations.

CONCLUSIONS

According to this study, we can conclude that the USA has had been leading the orthopedics research in the past 10 years. Although China still falls behind, it has made considerable progress in the orthopedics research, not only in quantity but also quality.

LEVEL OF EVIDENCE

IV.

The divergence pattern of Trichinella spiralis isolates from China revealed by mitochondrial and ribosomal markers

Trichinella spiralis is the main etiological agent of human trichinellosis. In China, trichinellosis remains a serious food-borne parasitic zoonosis and poses a serious threat to human health. However, the genetic structure of Chinese T. spiralis population is still little known. In this study, we used three molecular markers to analyze phylogeographic structure of the Chinese T. spiralis population. A total of 11 T. spiralis isolates were collected from 10 geographical locations in mainland China. The cytochrome c-oxidase gene (COI), large subunit ribosomal DNA (mt-lsrDNA) and 5S ribosomal DNA intergenic spacer region (5S ISR) genes of each isolate was amplified and sequenced. Only four haplotypes were found in these concatenated sequences. Both multimodal frequency distributions of mismatch analysis and the Bayesian skyline plot analysis rejected a possible population expansion of Chinese T. spiralis population. The phylogenetic inference based on neighbor-joining (NJ), maximum parsimony (MP), maximum likelihood (ML) and the Bayesian estimation of divergence times under the uncorrelated log-normal relaxed molecular-clock model suggested that the Chinese T. spiralis isolates started radiating in the late Miocene.

Influence of internal geometry on magnetization reversal in asymmetric permalloy rings

We report the magnetization reversal behavior of microstructured Ni₈₀Fe₂₀ rings using magneto-optic indicator film imaging and magnetometry. While the reversal behavior of rings with a symmetric (circular) interior hole agrees with micromagnetic simulations of an onion → vortex → onion transition, we experimentally demonstrate that rings possessing an elliptical hole with an aspect ratio of 2 exhibit complex reversal behavior comprising incoherent domain propagation in the rings. Magneto optic images reveal metastable magnetic configurations that illustrate this incoherent behavior. These results have important implications for understanding the reversal behavior of asymmetric ferromagnetic rings.

[Correlation analysis between glycolipids metabolism and clinicopathologic features in patients with gastric cancer]

OBJECTIVE

To analyze the correlation between glycolipids metabolism and clinicopathologic features in patients with gastric cancer.

METHODS

Glycolipids metabolism and clinicopathologic features of 443 gastric cancer patients were collected, and their correlation was analyzed.

RESULTS

Compared to gastric cancer patients with normal levels of glycolipids metabolism, there were less male patients who were with low level of total cholesterol (TCH)(χ(2)=7.676, P<0.05), and the number of male patients with low level of high-density lipoprotein (HDL) (χ(2)=7.520) and apoA1 (χ(2)=6.253) was higher (both P<0.05). Serum TCH level showed a negative correlation with age of patients (r=-0.116), tumor size (r=-0.117) and TNM stage (r=-0.111) (P<0.05); serum HDL level was negatively correlated with tumor diameter (r=-0.094), the number of metastatic lymph nodes (r=-0.106), primary tumor invasion depth (r=-0.112), metastatic lymph nodes stage (r=-0.102) and TNM stage (r=-0.107) (P<0.05); serum LDL was negatively correlated with age of patients (r=-0.116) (P<0.05); serum LPa was positively correlated with tumor size (r=0.170), the number of metastatic lymph nodes (r=0.151), primary tumor invasion depth (r=0.160), metastatic lymph nodes stage (r=0.153) and TNM stage (r=0.115) (P<0.05); apoA1 was negatively correlated with distant metastasis (r=-0.168) and TNM stage (r=-0.120) (P<0.05); and apoB was negatively correlated with distant metastases (r=-0.132, P<0.05). Levels of blood glucose and TG had no significant association with clinicopathological features of gastric cancer patients (P>0.05).

CONCLUSIONS

Low lipid metabolism but high level of LPa may be the metabolic characteristics of gastric cancer progression. Monitoring the changes of serum lipids levels could be valuable for the prognosis of patients with gastric cancer.

PTBP1 modulation of MCL1 expression regulates cellular apoptosis induced by antitubulin chemotherapeutics

Myeloid cell leukemia sequence 1 (MCL1), an anti-apoptotic BCL2 family protein, is a key regulator of intrinsic apoptosis. Normal cells require strict control over MCL1 expression with aberrant MCL1 expression linked to the emergence of various diseases and chemoresistance. Previous studies have detailed how MCL1 expression is regulated by multiple mechanisms both transcriptionally and translationally. However, characterization of the post-transcriptional regulators of MCL1 mRNA is limited. Polypyrimidine tract binding protein 1 (PTBP1) is a known regulator of post-transcriptional gene expression that can control mRNA splicing, translation, stability and localization. Here we demonstrate that PTBP1 binds to MCL1 mRNA and that knockdown of PTBP1 upregulates MCL1 expression in cancer cells by stabilizing MCL1 mRNA and increasing MCL1 mRNA accumulation in cytoplasm. Further, we show that depletion of PTBP1 protects cancer cells from antitubulin agent-induced apoptosis in a MCL1-dependent manner. Taken together, our findings suggest that PTBP1 is a novel regulator of MCL1 mRNA by which it controls apoptotic response to antitubulin chemotherapeutics.

Viability, morphology and function of primary endothelial cells on poly(n-butyl acrylate) networks having elastic moduli comparable to arteries

Soft hydrophobic poly(n-butyl acrylate) networks (cPnBA) were developed as entropy elastic substrates for passive mechanical stimulation of cells, where the elastic modulus of the cPnBAs could be systematically adjusted by variation of the cross-link density. The networks were synthesized by thermally-induced radical polymerization from n-butyl acrylate, with poly(propylene glycol) dimethacrylate (PPGDMA) acting as cross-linker, whereby the purity of the cPnBAs was confirmed by(1) H-NMR spectroscopy and gas chromatography. In this work two cPnBA polymer networks with an elastic modulus around 200 kPa and 1 MPa were investigated having an elastic modulus similar to that of arteries. Both cPnBAs exhibited an almost smooth surface with a surface roughness (R q) in the wet state ranging from 17 to 37 nm and a similar zetapotential, indicating an almost identical chemical composition within the topmost surface layer in terms of functional groups. In contrast, wettability of the samples was found to be different with an advancing angle ( advancing) of 123 ± 3.8° for cPnBA0250, while for cPnBA1100 significantly lower values for advancing (111 ± 3.8°) were obtained. First in vitro tests were performed with primary endothelial cells (HUVEC) to study its effects on vascular cell functions. Within the time period of cultivation (72 h), the cells on the cPnBA samples reached subconfluence and showed a viability rate of almost 100%. Although cell density differed after 72 h with more cells on cPnBA0250 than on cPnBA1100, both materials showed no significant effect on the cell morphology, the cellular LDH-release, which was used as marker for the integrity of the cell membrane, and the organisation of the VE-cadherin. However, lower cell density and less actin stress fibre formation on cPnBA1100 might indicate that cell-material interaction was weaker on cPnBA1100 than on cPnBA0250. The secretion of the vasoactive cytokines prostacyclin (PGI2) and thromboxane A2 (TXA2) was low compared to previously reported values. However, the anti-thrombogenic ratio of PGI2/TXA2 - which is balanced under physiological conditions - with much higher PGI2 compared to TXA2 (up to 17.6-fold after 72 h for cPnBA1100) suggests that this material might be effective to preventing thrombosis.

[Relationship between N-nitrosodimethylamine and risk of digestive tract cancers: a Meta analysis based on cohort studies]

OBJECTIVE

To analyze the relationship between N-nitrosodimethylamine(NDMA)and the risk of digestive tract cancers.

METHODS

The papers about the relationship between NDMA and the risk of digestive tract cancers published from 1980 to 2012 were retrieved following databases: Chinese BioMedical Literature Database(CBM), the Chinese Journal Full-text Database(CNKI), Wanfang Database, PubMed and EBSCO. The fix and random effect model was used and statistical analyses were conducted by using RevMan 5.1 software.

RESULTS

Thirteen papers were found, in which 7 about digestive tract cancers were used in this Meta analysis. The NDMA had significant positive effect on the incidence of digestive tract cancers(RR=1.12, 95% CI: 1.03-1.21). The relationship between NDMA and esophageal cancer was not significant(RR=1.18, 95%CI: 0.98-1.41)but NDMA could increase the risk of gastric cancer(RR=1.08, 95% CI: 1.00-1.18). For the subtypes of esophageal and gastric cancer, NDMA had positive relationship with esophageal squamous cell carcinoma(RR=1.72, 95% CI: 1.01-2.96), but had no significant relationship with esophageal adenocarcinoma, cardiac carcinoma and gastric adenocarcinoma.

CONCLUSION

The population-based cohort studies have showed that the NDMA could significantly increase the risk of digestive tract cancers, but the effects differed with subtypes of esophageal and gastric cancer. However, it is necessary to collect more evidence due to the limited studies and obvious differences in the study design, sampling and exposure measurement of these cohort studies.

[Burden of chronic obstructive pulmonary disease attributable to ambient ozone pollution in 1990 and 2013 in China]

OBJECTIVE

To investigate the burden of chronic obstructive pulmonary disease (COPD) in China attributable to ambient ozone pollution in 1990 and 2013.

METHODS

Based on the results of the China Global Burden of Disease Study (GBD) 2013, the population attributable fractions was used to analyze the deaths and disability-adjusted life years (DALY) of COPD attributable to ambient ozone pollution in all provinces (not including Taiwan, China) in 1990 and 2013, and to compare changes of the attributable disease burden in 1990 and 2013.

RESULTS

In 2013, 7.4% (95% uncertainty interval (95% UI): 6.1%-8.6%) of COPD were attributable to ambient ozone pollution, with the highest rate in Hebei province (15.0%, 95%UI: 12.0%-18.7%) and the lowest in Heilongjiang province (2.8%,95%UI: 0.9%-5.3%). In 2013, 67 485 COPD deaths in China were due to ambient ozone pollution, with the highest number in Sichuan province (11 929) and in China lowest in Macao (11). A total of 1.168 million DALYs caused by COPD were due to ambient ozone pollution, with the highest in Sichuan province (0.189 million) and lowest in Macao (257.4). In 2013, the DALY per 100 000 population caused by COPD due to ambient ozone pollution after age standardization was lowest in Heilongjiang province (21.9), Shanghai (26.7), Beijing (38.4), Tianjin (39.3), and Jilin province (39.7) and highest in Sichuan province (206.4), Qinghai province (202.5), Guizhou province (175.3), and Gansu province (171.4). DALYs caused by COPD attributable to ambient ozone pollution increased with age (0.144 million person years for ages 15-49 years, 0.43 million person years for age 50-69 years and 0.594 million person years for age 70 years and above), which were higher in men than in women (0.708 million person years for men and 0.459 million person years for women in 2013). Deaths of COPD attributable to ambient ozone pollution were 49 514 and 67 485 in 1990 and 2013, respectively. DALYs caused by COPD attributable to ozone pollution totaled 0.894 million and 1.168 million person years in 1990 and 2013, respectively. Ambient ozone pollution-related deaths and DALYs increased 36.3% and 30.6%, respectively.

CONCLUSION

Compared with 1990, the disease burden of COPD in 2013 attributed to ambient ozone pollution in China increased substantially. Ambient ozone pollution caused great losses among Chinese residents. More attention should be directed toward western provinces with a particularly high disease burden due to ambient ozone pollution.

HGF/Met and FOXM1 form a positive feedback loop and render pancreatic cancer cells resistance to Met inhibition and aggressive phenotypes

Purpose

Hepatocyte growth factor (HGF)/Met signaling plays critical roles in pancreatic ductal adenocarcinoma (PDA) development and progression and is considered a potential therapeutic target for this disease. However, the mechanism of aberrant activation of HGF/Met signaling and resistance to Met inhibition in PDA remains unclear.

Experimental Design

The mechanistic role of cross-talk between Forkhead box M1 (FOXM1) and HGF/Met signaling in promotion of PDA growth and resistance to Met inhibition was examined using cell culture, molecular biology and mouse models; and the relevance of our experimental and mechanistic findings were validated using human PDA tissues.

Results

Met was markedly overexpressed in both PDA cell lines and pancreatic tumor specimens, and the expression of Met correlated directly with that of FOXM1 in human tumor specimens. Mechanistically, FOXM1 bound to the promoter region of the Met gene and transcriptionally increased the expression of Met. Increased expression of FOXM1 enhanced the activation of HGF/Met signaling and its downstream pathways, including RAS/extracellular signal-regulated kinase 1/2, phosphoinositide 3-kinase/AKT, and signal transducer and activator of transcription 3. Furthermore, activation of HGF/Met signaling increased the expression and transcriptional activity of FOXM1, and the cross-talk between FOXM1 and HGF/Met signaling promoted PDA growth and resistance to Met inhibition.

Conclusions

Collectively, our findings identified a positive feedback loop formed by FOXM1 and HGF/Met and revealed that this loop is a potentially effective therapeutic target for PDA.

Treatment of tibia avulsion fracture of posterior cruciate ligament with high-strength suture fixation under arthroscopy

Aim

To evaluate the outcome of arthroscopy treatment using high-strength line in the treatment of tibial avulsion fracture of posterior cruciate ligament.

Methods

Both the avulsed bone block and the tibia bone bed were refreshed. The procedure was completed with the assistance of PCL director drill guide. The reduction and fixation using high-strength line were used to fix the avulsed bone by from posterior middle portal. Rehabilitation began early postoperatively.

Results

From January 2010 to June 2012, a total of 18 arthroscopically treated cases of PCL tibial avulsion fracture were retrospectively evaluated. Reduction of the avulsion fragment was obtained in all cases. 16 cases were followed up for 7–30 months (average 13.6), and 2 cases were out of follow-up. In the 16 followed patients, flexion and extension were back to normal within 6 weeks, and return to normal walk in 12 weeks. The bone healing was good without any vascular or nerve complications. All the patients regained the preinjury activity level. The mean score (and standard deviation) increased from 38.9 ± 4.9 points to 95.2 ± 3.8 points with the system of Lysholm, from 57.1 ± 10.3 points to 94.3 ± 4.4 points with the system of IKDC. Post-test displacement of KT3000 declined from 3.6 ± 0.39 to 1.1 ± 0.27 mm.

Conclusion

Arthroscopic vertical fixation by high-strength line is a simple, safe, reliable, and micro-invasive treatment to PCL tibial avulsion fracture. It is a kind of real all arthroscopic technique, and good for early postoperative rehabilitation. The total stability of the knee could be gained, and the second operation to remove the internal fixation is avoided.

Analysis of Structures, Functions, and Epitopes of Aminopeptidase from Trichinella spiralis

We have previously reported that the recombinant T. spiralis aminopeptidase (rTsAP) could induce a partial protective immunity against T. spiralis infection in mice. The aim of this study was to predict the structures and functions of TsAP protein by using the full length cDNA sequence of TsAP gene. TsAP sequence was 1515 bp length with a 1515 bp biggest ORF encoding 504-amino acid protein. The molecular weight and isoelectric point of TsAP were 54.7 kDa and 6.69, respectively. TsAP structure domains contained a Peptidase_M17_N and a Peptidase_M17 domain, which has the function of catalysis of the hydrolysis of N-terminal amino acid residues. TsAP had no signal peptide site and transmembrane domain, and located in cytoplasm. The secondary structure of TsAP contained 16 α-helix, 14 β-strand and 29 coils. The TsAP had 11 and 21 potential antigenic epitopes of T cell and B cell, respectively. Based on the phylogenetic analyses of TsAP, T. spiralis have the closest relationship with Plasmodium falciparum. TsAP was a kind of proteolytic enzyme with a variety of biological functions and its antigenic epitopes could provide important insights on the diagnostic antigens and target molecular of anti-Trichinella drugs.

1,25(OH)2D3 downregulates the Toll-like receptor 4-mediated inflammatory pathway and ameliorates liver injury in diabetic rats

BACKGROUND

Fatty acid deposition in the liver can activate a number of pro-inflammatory signaling pathways such as the Toll-like receptor 4 (TLR4) pathway, which may be important in the pathogenesis of nonalcoholic steatohepatitis. 1,25(OH)2D3 downregulates the expression of TLR4 and may represent a novel treatment strategy for reducing hepatocyte injury. Therefore, in this study, we investigated the protective effects of 1,25(OH)2D3 on diabetic liver injury in vivo.

METHODS

Streptozotocin (STZ)-induced diabetic rats were randomly divided into five groups and treated with low-dose 1,25(OH)2D3 (0.025 μg/kg/day), medium-dose 1,25(OH)2D3 (0.15 μg/kg/day), high-dose 1,25(OH)2D3 (0.3 μg/kg/day), insulin (protamine zinc insulin 16 U/kg/day, subcutaneous injection), or no intervention (the control group). Sixteen weeks later, the rats were killed, and blood samples were obtained to test lipid profiles and hepatic function. The infiltration of inflammatory cells, the level of fibrosis, and the expression levels of TLR4, nuclear factor-kappa B (NF-κB), and tumor necrosis factor-α (TNF-α) in the liver were analyzed. The hepatocytes were treated with vehicle control, LPS (100 ng), high fat [DMEM + FFA (0.1 mM: palmitic acid, oleic acid, 1:2)], LPS + high fat, vehicle + 1,25(OH)2D3 (10(-7) M), LPS + 1,25(OH)2D3, high fat + 1,25(OH)2D3, or LPS + high fat + 1,25(OH)2D3. RNA and protein were extracted to detect the expression of TLR4 and downstream inflammatory factors such as NF-ΚB, TNF-α, and IL-6. Groups of data were compared by single factor variance analysis.

RESULTS

High-dose 1,25(OH)2D3 administration for 16 weeks downregulated the expression of TLR4, NF-κB, and TNF-α in the liver tissue of diabetic rats and attenuated hepatic inflammation and fibrosis, as shown by immunohistochemical staining, hematoxylin and eosin staining, Masson's trichrome staining, reverse transcription polymerase chain reaction (RT-PCR), and western blotting. In vitro, hepatocytes treated with high fat or LPS exhibited significantly increased expression of TLR4, NF-κB, and downstream inflammatory factors (P < 0.05). Intervention with 1,25(OH)2D3 decreased the expression of TLR4, NF-κB, and inflammatory factors (P < 0.05).

CONCLUSIONS

1,25(OH)2D3 exhibited protective effects against diabetes-related liver injury, possibly through downregulation of components of the TLR4 signaling pathway.

Copy number variations of HLA-I and activation of NKp30 pathway determine the sensitivity of gastric cancer cells to the cytotoxicity of natural killer cells

Nude mice are important in vivo model for characterization of cell malignancy behavior; however, many cancer cells fail to form tumors in it. Understanding this defective mechanism may provide novel insights into tumorigenesis and how tumor cells escape innate immunity. Whole-genome sequencing was conducted on two gastric cancer (GC) cells, BGC823 and AGS, which do and do not form tumors in nude mice, to identify their genomic differences relevant to natural killer (NK) cells. We found that the tumorigenic capacity of human GC cell lines was dependent on the recruitment and activation of NK cells in xenograft tumors. We used whole-genome sequence (WGS) on GC cell lines to identify potential genes controlling susceptibility to NK-mediated killing. The tumorigenic cell line BGC823 expressed high levels of HLA-I because of copy gain and was resistant to NK cell killing. In contrast, another cell line AGS expressing low levels of HLA-I with activated NKp30/MAPK/IL-12 (interleukin-12) or IL-2 (interleukin-2) pathway was susceptible to NK lysis. Treatment of tumor bearing mice with systemic administration of IL-12 in combination with intratumor injection of anti-HLA-I antibody significantly increased NK cell recruitment into xenograft tumors, which became sensitive to NK killing, resulting in reduced tumor progression. In human GC specimens, decreased HLA-I expression and increased NK cells surrounding tumor cells were correlated with decreased metastasis potential and better prognosis of patients. Our results provide a mechanistic basis for GC cells to escape NK lysis and a promising prospect of NK immunotherapy for GC cells.

Cloning and characterization of DELLA genes in Artemisia annua

Gibberellins (GA) are some of the most important phytohormones involved in plant development. DELLA proteins are negative regulators of GA signaling in many plants. In this study, the full-length cDNA sequences of three DELLA genes were cloned from Artemisia annua. Phylogenetic analysis revealed that AaDELLA1 and AaDELLA2 were located in the same cluster, but AaDELLA3 was not. Subcellular localization analysis suggested that AaDELLAs can be targeted to the nucleus and/or cytoplasm. Real-time PCR indicated that all three AaDELLA genes exhibited the highest expression in seeds. Expression of all AaDELLA genes was enhanced by exogenous MeJA treatment but inhibited by GA3 treatment. Yeast two-hybrid assay showed that AaDELLAs could interact with basic helix-loop-helix transcription factor AaMYC2, suggesting that GA and JA signaling may be involved in cross-talk via DELLA and MYC2 interaction in A. annua.

Computational identification and characterization of conserved miRNAs and their target genes in beet (Beta vulgaris)

Highly conserved endogenous non-coding microRNAs (miRNAs) play important roles in plants and animals by silencing genes via destruction or blocking of translation of homologous mRNA. Sugar beet, Beta vulgaris, is one of the most important sugar crops in China, with properties that include wide adaptability and strong tolerance to salinity and impoverished soils. Seedlings of B. vulgaris can grow in soils containing up to 0.6% salt; it is important to understand the molecular mechanisms of salt tolerance to enrich genetic resources for breeding salt-tolerant sugar beets. Here, we report 13 mature miRNAs from 12 families, predicted using an in silico approach from 29,857 expressed sequence tags and 279,223 genome survey sequences. The psRNATarget server predicted 25 target genes for the 13 miRNAs. Most of the target genes appeared to encode transcription factors or were involved in metabolism, signal transduction, stress response, growth, and development. These results improve our understanding of the molecular mechanisms of miRNA in beet and may aid in the development of novel and precise techniques for understanding post-transcriptional gene-silencing mechanisms in response to stress tolerance.