Identifying interactive effects of spatial drivers in soil heavy metal pollutants using interpretable machine learning models

The accurate identification of spatial drivers is crucial for effectively managing soil heavy metals (SHM). However, understanding the complex and diverse spatial drivers of SHM and their interactive effects remains a significant challenge. In this study, we present a comprehensive analysis framework that integrates Geodetector, CatBoost, and SHapley Additive exPlanations (SHAP) techniques to identify and elucidate the interactive effects of spatial drivers in SHM within the Pearl River Delta (PRD) region of China. Our investigation incorporated fourteen environmental factors and focused on the pollution levels of three prominent heavy metals: Hg, Cd, and Zn. These findings provide several key insights: (1) The distribution of SHM is influenced by the combined effects of various individual factors and interactions within the source-flow-sink process. (2) Compared with the spatial interpretation of individual factors, the interaction between Hg and Cd exhibited enhanced spatial explanatory power. Similarly, interactions involving Zn mainly demonstrated increased spatial explanatory power, but there was one exception in which a weakening was observed. (3) Spatial heterogeneity plays a crucial role in determining the contributions of environmental factors to soil heavy metal concentrations. Although individual factors generally promote metal accumulation, their effects fluctuate when interactions are considered. (4) The SHAP interpretable method effectively addresses the limitations associated with machine-learning models by providing understandable insights into heavy metal pollution. This enables a comparison of the importance of environmental factors and elucidates their directional impacts, thereby aiding in the understanding of interaction mechanisms. The methods and findings presented in this study offer valuable insights into the spatial heterogeneity of heavy metal pollution in soil. By focusing on the effects of interactive factors, we aimed to develop more accurate strategies for managing SHM pollution.

Polymicrobial Infection Induces Adipose Tissue Dysfunction via Gingival Extracellular Vesicles

Recent studies have indicated that periodontitis promotes metabolic dysregulation and insulin resistance by affecting the function of white adipose tissue (WAT). However, the mechanisms linking periodontitis to adipose tissue dysfunction still need to be explored. Extracellular vesicles (EVs) deliver messages to distal sites and regulate their function. Also, recent studies have shown that periodontitis changes the composition of EVs in body fluids and that EVs might be one of the mechanisms underlying the relationship between periodontitis and insulin resistance. Herein, we explored the impact of polymicrobial oral infection with periodontal pathogens on the function of WAT and the role of gingival EVs (gEVs) in the process. Mice were subjected to oral inoculation with 109 Porphyromonas gingivalis and 108 Fusobacterium nucleatum every other day for 14 wk. This prolonged bacterial infection induced WAT dysfunction, characterized by reduced levels of AKT phosphorylation, adiponectin, leptin, and genes associated with adipogenesis and lipogenesis. We successfully isolated gEVs with satisfactory yield and purity. The RNA sequencing results showed that the differentially expressed microRNAs in the gEVs of mice with polymicrobial oral infection were involved in insulin signaling and adipose tissue function. Notably, our in vitro experiments and RNA sequencing results revealed the functional similarities between gEVs and plasma-derived EVs. Furthermore, intraperitoneal injection with gEVs derived from mice with oral infection induced the dysfunction of WAT in healthy mice. Overall, our findings provide evidence for the influence of polymicrobial oral infection on WAT function and propose gEVs as a novel pathway through which periodontal infection may exert its effects on WAT.

Copper Ion-Modified Germanium Phosphorus Nanosheets Integrated with an Electroactive and Biodegradable Hydrogel for Neuro-Vascularized Bone Regeneration

Severe bone defects accompanied by vascular and peripheral nerve injuries represent a huge orthopedic challenge and are often accompanied by the risk of infection. Thus, biomaterials with antibacterial and neurovascular regeneration properties are highly desirable. Here, a newly designed biohybrid biodegradable hydrogel (GelMA) containing copper ion-modified germanium-phosphorus (GeP) nanosheets, which act as neuro-vascular regeneration and antibacterial agents, is designed. The copper ion modification process serves to improve the stability of the GeP nanosheets and offers a platform for the sustained release of bioactive ions. Study findings show that GelMA/GeP@Cu has effective antibacterial properties. The integrated hydrogel can significantly boost the osteogenic differentiation of bone marrow mesenchymal stem cells, facilitate angiogenesis in human umbilical vein endothelial cells, and up-regulate neural differentiation-related proteins in neural stem cells in vitro. In vivo, in the rat calvarial bone defect mode, the GelMA/GeP@Cu hydrogel is found to enhance angiogenesis and neurogenesis, eventually contributing to bone regeneration. These findings indicate that in the field of bone tissue engineering, GelMA/GeP@Cu can serve as a valuable biomaterial for neuro-vascularized bone regeneration and infection prevention.

The anterior talofibular ligament: A thin-slice three-dimensional magnetic resonance imaging study

PURPOSE

The aim of this study was to provide an accurate and improved understanding of anterior talofibular ligament (ATFL) anatomy, and to determine the exact positioning and diameter of the bony tunnel during ATFL repair and/or reconstruction surgery.

METHOD

A total of 58 healthy asymptomatic volunteers were examined, wherein 38 underwent bilateral ankle 3D MRI, and 20 underwent unilateral ankle 3D MRI (10 left and 10 right ankles). Data from a total of 96 MRI datasets were collected. The MRI data from these cases were exported into Mimics to enable reconstruction of 3D ATFL models. The resulting image quality was evaluated using a 5-point subjective scoring system. In addition, the length, width, thickness, and positioning of each ATFL and the area of the ATFL footprints were identified within the 3D model using Mimics and SolidWorks.

RESULTS

The image quality score was 4.48 ± 0.50. The ATFL formed one (65.6%), two (31.3%), or three (3.1%) bundles forms. The footprint area was 31.25 ± 6.29 mm² on the fibular side, and 17.48 ± 4.49 mm² on the talar side.

CONCLUSION

Thin-slice 3D MRI aids in the reconstruction of the 3D ATFL model, and it provides reference for the accurate anatomy of the area and location of the ATFL. This technology will facilitate diagnosis of ATFL injuries and choice of surgical methods.

LEVEL OF EVIDENCE

level IV.

Morphologic evaluation of injured and contralateral uninjured ankles in patients with unilateral chronic ankle instability

OBJECTIVE

To compare the morphological anatomy and abnormalities of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) in unilateral chronic ankle instability (CAI).

METHODS

22 patients (men: women, 13:9; mean age, 28.95 ± 8.127 years) with unilateral CAI and 18 healthy volunteers (men: women, 9:9, mean age, 28.33 ± 3.678 years) were recruited. MRI scans were divided into Group 1 (22 injured ankles), Group 2 (22 contralateral uninjured ankles), and Group 3 (36 healthy volunteer ankles). The morphologic variables, MRI signal intensity (SI) values were evaluated.

RESULTS

The ATFL proximal, intermediate, and distal sites and the CFL proximal and distal sites in Group 3 were narrower than those in Group 1 (P ＜0.05). Both ATFL and CFL in Group 1 were thicker than those in Group 3 (P ＜0.01). The proximal and intermediate sites of the ATFL and the proximal site of the CFL in Group 3 were narrower than those in Group 2 (P ＜0.01). The intermediate site of the ATFL and the proximal and distal sites of the CFL in Group 2 were thicker than those in Group 3 (P ＜0.01). The mean SI values of the ATFL in Group 1 were higher than those in Groups 2 and 3 (P ＜0.01). The ATFL and CFL SI values were higher in Group 2 than those in Group 3 (P ＜0.05).

CONCLUSION

Both the injured and contralateral uninjured ankles had wider ATFL and CFL, more thickness, and higher SI values compared with those of healthy volunteer ankles.

ADVANCES IN KNOWLEDGE

High-resolution three-dimensional MRI provides a potential tool assisting clinical decision on the treatment and rehabilitation therapy of patients with unilateral CAI.

Silicon-Phosphorus-Nanosheets-Integrated 3D-Printable Hydrogel as a Bioactive and Biodegradable Scaffold for Vascularized Bone Regeneration

Natural bone is a highly vascularized tissue that relies on the vasculature for blood and nutrients supply to maintain skeletal integrity. Bioactive nanomaterials with the capability of improving vascularized bone regeneration are highly demanded for bone tissue engineering. In this work, 2D silicon phosphorus (SiP) is explored as a new kind of bioactive and biodegradable nanomaterial with excellent angiogenesis and osteogenesis, and a 3D printed biohybrid hydrogel of GelMA-PEGDA incorporated with photocrosslinkable SiP-nanosheet (GelMA-PEGDA/SiPAC) is developed to apply on bone tissue engineering. Findings show that the GelMA-PEGDA/SiPAC possessess excellent biocompatibility and biodegradability, and can sustainably release Si and P elements. Compared with the biohybrid hydrogel scaffolds incorporated with black phosphorus nanosheets, the GelMA-PEGDA/SiPAC can further enhance the osteogenesis of mesenchymal stem cells, and tubular networking of human umbilical vascular endothelial cells. In a rat calvarial bone defect model, the superior angiogenesis and osteogenesis induced by GelMA-PEGDA/SiPAC have been confirmed in vivo. The current strategy paves a new way to design a multifunctional SiP nanocomposite scaffold on mediating the osteogenesis and angiogenesis in one system, and provides a bioactive and biodegradable alternative nanomaterial for tissue engineering and regenerative medicine.

Diagnosis and follow-up MRI evaluation of tennis leg:New understanding of the pathogenesis and imaging

OBJECTIVES

To evaluate the Magnetic resonance imaging (MRI) findings of patients with a clinical diagnosis of tennis leg and to explore the pathogenesis of tennis leg.

METHODS

A retrospective review of 58 (45 men, 13 women; age range, 7-81 years; mean age, 46.7 years) patients with a clinical diagnosis of tennis leg at our hospital during a 64-month period (May 2014 through Sep 2019) was conducted. All patients underwent MRI scan. Follow-up MRI was performed on 4 patients. Images findings, including integrity of the myotendinous junction and tendon of the gastrocnemius and soleus, and presence of fluid collection were analyzed.

RESULTS

MRI revealed fluid collection between the medial head of the gastrocnemius and soleus in 44 cases (72.1%). In 25 cases (41.0%), the collected fluid spread to around the medial border of fascia cruris. Fifty-five cases (90.2%) had edema or disruption of the gastrocnemius, with most cases (n = 55) showing edema or disruption of the medial head of the gastrocnemius at the myotendinous junction. Twenty-two (36.1%) cases had edema or disruption of the soleus, with most cases (n = 17) showing edema or disruption of the soleus at the myotendinous junction. Plantaris tendon disruption was observed in 7 cases (11.5%). A thick area of reparative tissue at the distal myotendinous junction of the medial head of the gastrocnemius was observed in all 4 MRI patients followed up.

CONCLUSION

Abnormalities of the medial head of the gastrocnemius at the myotendinous junction and tendon appear to be more common than those of the plantaris tendon. Reparative tissue at the distal myotendinous junction of the medial head of the gastrocnemius may be an important specific indication of chronic tennis leg injury.

Platelet-Rich Plasma-Derived Exosomal USP15 Promotes Cutaneous Wound Healing via Deubiquitinating EIF4A1

Epithelial regeneration is an essential wound healing process, and recent work suggests that different types of exosomes (Exos) can improve wound repair outcomes by promoting such epithelial regeneration. Platelet-rich plasma (PRP) is known to facilitate enhanced wound healing, yet the mechanisms underlying its activity are poorly understood. To explore these mechanisms, we first isolated PRP-derived Exos (PRP-Exos). Using immortalized keratinocytes (HaCaT cells) treated with PBS, PRP, or PRP-Exos, we conducted a series of in vitro Cell Counting Kit-8 (CCK-8), EdU, scratch wound, and transwell assays. We then established a wound defect model in vivo in mice and assessed differences in the mRNA expression within these wounds to better understand the basis for PRP-mediated wound healing. The functions of PRP-Exos and USP15 in the context of wound healing were then confirmed through additional in vitro and in vivo experiments. We found that PRP-Exos effectively promoted the in vitro proliferation, migration, and wound healing activity of HaCaT cells. USP15 was further identified as a key mediator through which these PRP-Exos were able to promote tissue repair both in vitro and in vivo. At a mechanistic level, USP15 enhanced the functional properties of HaCaT cells by promoting EIF4A1 deubiquitination. Thus, PRP-Exos and USP15 represent promising tools that can promote wound healing via enhancing epithelial regeneration.

Evaluation of 3-Dimensional Magnetic Resonance Imaging (3D MRI) in Diagnosing Anterior Talofibular Ligament Injury

BACKGROUND It is challenging to entirely show the anterior talofibular ligament (ATFL) and accurately diagnose ATFL injury with traditional 2-dimensional (2D) magnetic resonance imaging (MRI). With the introduction of 3.0T MRI, a 3-dimensional (3D) MRI sequence can achieve images with high spatial resolution. This study aimed to evaluate the accuracy of 3D MRI and compare it with 2D MRI in diagnosing ATFL injury. MATERIAL AND METHODS This was a prospective study in which 45 patients with clinically suspected ATFL injury underwent 2D MRI, 3D MRI, and 3D model reconstruction followed by arthroscopic surgery between February 2018 and April 2019. Two radiologists who had over 11 and 13 years of musculoskeletal experience assessed the injury of ATFL in consensus without any clinical clues. Arthroscopic surgery results were the standard reference of MRI accuracy. RESULTS The 3D MRI results of ATFL injury showed the sensitivity of diagnosis of complete tears of 83% and specificity of 82%. The partial tears diagnosis sensitivity was 78%, and specificity was 100%. The sensitivity of diagnosis of sprains was 100%, and the specificity was 97%. The 3D MRI accuracy of diagnosis was 98% for no injury, 98% for sprain, 91% for partial tear, and 82% for complete tear. The difference in the diagnosis of sprain and partial tears by 3D MRI and 2D MRI was statistically significant (P<0.05). A 3D reconstruction model was successfully created for all patients. CONCLUSIONS 3D MRI may be a reliable and accurate method to detect ATFL injury. The 3D reconstruction model using 3D MRI sequences has excellent prospects in application.

Genome-wide association studies for growth-related traits in a crossbreed pig population

Growth-related traits are important economic traits in the pig industry that directly influence pork production efficiency. To detect quantitative trait loci and candidate genes affecting growth traits, genome-wide association studies were performed for backfat thickness (BF) and loin muscle depth (LMD) in 370 Chuying-black pigs using Illumina PorcineSNP50 BeadChip array. We totally identified 14 BF-associated SNPs, which included 11 genome-wide SNPs (P < 1.39E-06) and 3 chromosome-wide suggestive SNPs (P < 2.79E-05) and for LMD, 9 SNPs surpassed the genome-wide significant threshold (P < 1.39E-06). These SNPs explained 30.33 and 27.51% phenotypic variance for BF and LMD respectively. Furthermore, 14 and 9 genes nearest to the significant SNPs were selected to be candidate genes, including MAGED1, GPHN, CCSER1, and GUCY2D for BF and PARM1, COL18A1, HSF5, and SCML2 genes for LMD. One significant SNP, which explained 6.07% of phenotypic variance for BF, mapped to a pleiotropic quantitative trait locus with a 494-kb interval. Together, the SNPs and candidate genes identified in this study will advance our understanding of the complex genetic architecture of BF and LMD traits, and they will also provide important clues for future implementation of a genomic selection program in Chuying-black pigs.

Inhibition of exosomal miR-24-3p in diabetes restores angiogenesis and facilitates wound repair via targeting PIK3R3

Diabetic foot ulcer (DFU) is one of the common ailments of elderly people suffering from diabetes. Exosomes containing various active regulators have been found to play a significant role in apoptosis, cell proliferation and other biological processes. However, the effect and the underlying mechanism of action of diabetes patients derived from circulating exosomes (Dia-Exos) on DFU remain unclear. Herein, we aim to explore the potential regulatory role of Dia-Exos. First, we attempted to demonstrate the harmful effect of Dia-Exos both in vivo and in vitro. miRNA-24-3p (miR-24-3p) was found enriched with Dia-Exos. Hence, inhibition of this miRNA could partially reverse the negative effect of Dia-Exos, thus, in ture, accelerates wound repair. Luciferase assay further verified the binding of miR-24-3p to the 3'-UTR of phosphatidylinositol 3-kinase regulatory subunit gamma (PIK3R3) mRNA and the PIK3R3 expression enhanced human umbilical vein endothelial cells functionality in vitro. Hence, the findings of this study reveal the regulatory role of Dia-Exos in the process of wound healing and provide experimental evidence for the therapeutic effects of knocking down miR-24-3p in DFU treatment.

Suture Anchor Versus Allogenic Tendon Suture in Treatment of Haglund Syndrome

Background

Haglund’s deformity is an abnormal bony enlargement on the back of the heel. It can cause the impact of the posterior calcaneal bursa and Achilles tendon insertion, and finally result in pain. This syndrome is called Haglund syndrome. The purpose of this study was to explore the effect of the suture anchor and allogeneic tendon suture in the treatment of Haglund syndrome.

Material/Methods

We retrospectively studied 20 patients with Haglund syndrome treated from January 2015 to December 2016. The patients were randomly divided into Group 1 (the suture anchor group) and Group 2 (the allogeneic tendon group), with 10 patients in each group and an average follow-up of 32 months after surgery. The AOFAS, VAS, and Arner-Lindholm scales were used to summarize the patient follow-up results and complications.

Results

In the 2 groups of patients, the postoperative AOFAS, VAS scores, and the Arner-Lindholm scale showed good results. However, the postoperative AOFAS score and VAS of the suture anchor group were better than those of the allogeneic tendon group, with shorter operation times. No Achilles tendon rupture or wound infection occurred during the entire postoperative period in either group. These results show the superiority of suture anchors.

Conclusions

The higher AOFAS and VAS score and shorter operation time in the suture anchor group suggest it is the better alternative for treatment of Haglund syndrome.

Chiauranib selectively inhibits colorectal cancer with KRAS wild-type by modulation of ROS through activating the p53 signaling pathway

Colorectal cancer (CRC) is one of the top three most deadly cancers despite using chemotherapy based on oxaliplatin or irinotecan combined with targeted therapy. Chiauranib has recently been identified to be a promising anticancer candidate with impressive efficacy and safety. However, the role and molecular mechanisms of Chiauranib in the treatment of CRC remain to be elucidated. Our study shows that Chiauranib inhibits cell proliferation and induces apoptosis in KRAS wild-type CRC cells in a dose- and time-dependent manner, but not mutation ones. Meanwhile, Chiauranib increases ROS production in KRAS wild-type CRC cells. Moreover, Chiauranib selectively suppresses KRAS wild-type CRC cells growth in vivo. Mechanistically, Chiauranib inhibits KRAS wild-type CRC cells by triggering ROS production via activating the p53 signaling pathway. Further, KRAS mutation CRC cells are resistant to Chiauranib by increasing Nrf2 to stably elevate the basal antioxidant program and thereby lower intracellular ROS induced by Chiauranib. Our findings provide the rationale for further clinical evaluation of Chiauranib as a therapeutic agent in treating KRAS wild-type CRC.

Inhibition of miRNA-152-3p enhances diabetic wound repair via upregulation of PTEN

Diabetic foot ulcer (DFU) is a major complication of diabetes in the elderly population. The aim of this study was to investigate the potential mechanism of DFU at the molecular level and explore a feasible therapy for it. Using data from the Gene Expression Omnibus (GEO) database, we found that phosphatase and tensin homolog (PTEN) is differentially expressed between diabetic patients and those without diabetes. We also found that PTEN expression is regulated by glucose stimulation. In addition, decreased function of human umbilical vein endothelial cells (HUVECs) was found to be associated with reduction of PTEN. We identified microRNA-152-3p (miR-152-3p) to be a putative upstream negative regulator of PTEN, and in vivo and in vitro results indicated that miR-152-3p antagonist could restore HUVEC function and accelerate wound repair. Thus, miR-152-3p-induced downregulation of PTEN appears responsible for the delayed wound healing in DFU, and miR-152-3p inhibition may effectively accelerate wound repair, thereby providing a potential target for DFU therapy.

LHPP inhibits hepatocellular carcinoma cell growth and metastasis

Hepatocellular carcinoma (HCC) has a poor prognosis, owing to its high potential for growth and metastasis. In this study, we aimed to investigate the roles of Phospholysine Phosphohistidine Inorganic Pyrophosphate Phosphatase (LHPP)in human HCCcell growth and metastasis. We analyzed the LHPP expression level in human HCC tissues paired normal tissues in the Oncomine database, and assessed the relationship between the LHPP expression levels with HCC patient's overall survival and the prognostic value of LHPP in human HCC by Kaplan-Meier survival analysis. Real-time PCR and Western Blot were used to examine the expression levels of LHPP in normal liver cell line (LO2) and human HCC cell lines (SMCC-7721, HepG2, Huh7, MHCC-97 H, and LM3). Through lentivirus infection, we established human HCC stable cell lines (Huh7 and LM3) overexpressing LHPP. Then, we detected these cell viability, colony , and invasion. Subsequently, we performed the gene set enrichment analysis (GSEA) for the RNA-seq data of HCC patients from TCGA. Finally, we examined the expression level of several oncogenes, including CCNB1, PKM2, MMP7, and MMP9, in these cells via real-time PCR assay. Here, we found thatLHPPis significantly downregulated in the human HCC tissues paired normal tissues. Furthermore, the high expression level of LHPP is associated with better clinical outcomes in human HCC. Overexpression of LHPPinhibitscell growth and metastasis in human HCC cells, and LHPP expression levels negatively correlate with cell cycle and metastasis in HCC tissues. Moreover, the level of LHPP is negatively correlated with CCNB1, PKM2, MMP7, and MMP9 in human HCC cells and HCC tissues. These findings highlight a novel tumor suppressor in human HCC growth and metastasis, and provide a promising diagnostic and prognostic factor for humanHCC.

Therapeutic effect of omega-3 fatty acids on T cell-mediated autoimmune diseases

The present study was to demonstrate that the G protein coupled receptors serve as targets for the treatment of autoimmune disease such as rheumatoid arthritis and multiple sclerosis. Rats received pristane at the base of the tail. Affected joints were counted daily. The T cell mediated autoimmune diseases such as pristine-induced arthritis (PIA) and autoimmune encephalomyelitis (EAE) in a rat model were profoundly ameliorated by treatment with the specific G protein couple receptors 120 (GPR120) stimuli omega-3 fatty acids (ω-3 FAs). Our study further revealed that the activation of GPR120 by ω-3 FAs can result in a decrease of phosphorylated transforming growth factor-β activated kinase 1 (TAK1), and further inhibit the downstream IKKβ/I-κB pathway and the terminal NF-κB activation which serves as a mediator of T cell activation. ω-3 Fatty acids exhibited an inhibitory effect on TAK1 by enhancing the association of β-arrestin2 and TAK1 binding protein 1 (TAB1), thus the disassociation of TAB1 from the TAB1/TAK1 complex renders a limited effect on β-arrestin2 signaling as an innate immunity regulation. GPR120 is a functional receptor of ω-3 fatty acids in T cell-mediated autoimmune disease compared with its effect on innate immunity.

miR-362-5p promotes cell proliferation and cell cycle progression by targeting GAS7 in acute myeloid leukemia

Recently, miR-362-5p has attracted special interest as a novel prognostic predictor in acute myeloid leukemia (AML). However, its biological function and underlying molecular mechanism in AML remain to be further defined. Herein, we found that a significant increase in miR-362-5p expression was observed in AML patients and cell lines using quantitative real-time PCR. The expression of miR-362-5p was altered in THP-1 and HL-60 cells by transfecting with miR-362-5p mimic or inhibitor. A series of experiments showed that inhibition of miR-362-5p expression significantly suppressed cell proliferation, induced G0/G1 phase arrest and attenuated tumor growth in vivo. On the contrary, ectopic expression of miR-362-5p resulted in enhanced cell proliferation, cell cycle progression and tumor growth. Moreover, growth arrest-specific 7 (GAS7) was confirmed as a direct target gene of miR-362-5p and was negatively modulated by miR-362-5p. GAS7 overexpression imitated the tumor suppressive effect of silenced miR-362-5p on THP-1 cells. Furthermore, miR-362-5p knockdown or GAS7 overexpression obviously down-regulated the expression levels of PCNA, CDK4 and cyclin D1, but up-regulated p21 expression. Collectively, our findings demonstrate that miR-362-5p exerts oncogenic effects in AML by directly targeting GAS7, which might provide a promising therapeutic target for AML.

MMP-sensitive PEG hydrogel modified with RGD promotes bFGF, VEGF and EPC-mediated angiogenesis

Traumatic soft tissue defects such as bedsores, chronic skin ulcers, limb necrosis, osteonecrosis and other ischemic orthopedic diseases are the most clinically intractable and common problems in orthopedics due to unsatisfactory conventional treatments. The present study designed poly(ethylene glycol; PEG) hydrogels with covalently binded arginylglycylaspartic acid (RGD). Endothelial progenitor cells (EPCs) were encapsulated in the modified hydrogel along with vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Results demonstrated that the modified hydrogel displayed good mechanical properties appropriate for a sustained release carrier. RGD modification significantly promoted EPC biocompatibility. VEGF and bFGF encapsulation enhanced the adhesion of EPCs, promoted the production of extracellular matrix and facilitated EPC proliferation. In addition, bFGF and VEGF induced angiogenesis. The combination of growth factors and EPCs in the hydrogel displayed a strong synergy to improve biocompatibility. The present results provided a potential novel treatment approach for soft tissue defects such as bone exposure, chronic skin ulcers, bedsores, limb necrosis, osteonecrosis and other ischemic diseases.

Effect of umbelliferone on adjuvant-induced arthritis in rats by MAPK/NF-κB pathway

Purpose

Umbelliferone (Umb), a member of coumarin family, is found in many plants and is a promising molecule with potential anti-inflammatory, anti-oxidative, and anti-tumor activities. However, the effect of Umb on arthritis remains unclear.

Methods

A rat model with Freund's complete adjuvant (FCA)-induced arthritis was developed and used to test the efficacy of Umb on arthritis rats. Rats were given an intragastric injection of Umb (20 and 40 mg/kg) once daily from days 21 to 28 after the administration of FCA. Hind paw volume was assessed using a volume meter. The pro-inflammatory cytokine levels and prostaglandin E2 (PEG2) level in serum and synovial fluid were detected by ELISA. HE staining was used to determine representative histological changes in joint tissues, and Western blot analysis was employed to study the effects of Umb on MAPK/NF-κB signaling pathway.

Results

Our results showed that Umb suppressed the release of IL-6, IL-1β, tumor necrosis factor-alpha, and PEG2. In addition, Umb could also dramatically ameliorate the pathological changes observed in rat joints. Based on the results of Western blot, we also observed that Umb could strikingly suppress the expression of MAPK/NF-κB pathway molecules.

Conclusion

These results proved that treatment with Umb is very effective for arthritis and inhibiting the MAPK/NF-κB signaling pathway may be a potential therapeutic target for treatment of arthritis.

Efficient nitrogen-vacancy centers' fluorescence excitation and collection from micrometer-sized diamond by a tapered optical fiber in endoscope-type configuration

Using an optical fiber to both excite the nitrogen-vacancy (NV) center in diamond and collect its fluorescence is essential to build NV-based endoscope-type sensor. Such endoscope-type sensor can reach inaccessible fields for traditional NV-based sensors built by bulky optical components and extend the application areas. Since single NV's fluorescence is weak and can easily be buried in fluorescence from optical fiber core's oxide defects excited by the green laser, fixing a micrometer size diamond containing high-density NVs rather than a nanodiamond containing single NV or several NVs on the apex of an optical fiber to build an endoscope-type sensor is more implementable. Unfortunately, due to small numerical aperture (NA), most of the optical fibers have a low fluorescence collection efficiency, which limits the sensitivity and spatial resolution of the NV-based endoscope-type sensor. Here, using a tapered optical fiber (TOF) tip, we significantly improve the efficiency of the laser excitation and fluorescence collection of the NV ensembles in diamond. This could potentially enhance the sensitivity and spatial resolution of the NV-based endoscope-type sensor. Numerical calculations show that the TOF tip delivers a high NA and has a high NV excitation and fluorescence collection efficiency. Experiments demonstrate that such TOF tip can obtain up to over 7-fold excitation efficiency and over 15-fold fluorescence collection efficiency of that from a flat-ended fiber (non-TOF) tip.

Dietary vitamin C intake and the risk of hip fracture: a dose-response meta-analysis

The meta-analysis suggested that dietary vitamin C was statistically inversely associated with the risk of hip fracture (overall OR = 0.73, 95% CI = 0.55-0.97, I ² = 69.1%) and with the increase of 50 mg/day vitamin C intake, the risk of hip fracture will reduce by 5% (OR = 0.95, 95% CI 0.91-1.00, P = 0.05).

INTRODUCTION

Previous studies had inconsistent findings regarding the association between vitamin C intake and the risk of hip fracture. Therefore, we conducted a meta-analysis to evaluate the association of dietary vitamin C intake and the risk of hip fracture.

METHODS

Relevant studies were identified by searching PubMed, Embase, and Web of Science up to December 2016. Additional articles were identified from reviewing the reference lists of relevant articles. The summary relative risks (RRs) or odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by random effects model. Funnel plot and Egger's test were used to test publication bias.

RESULTS

The total six articles containing 7908 controls and 2899 cases of hip fracture were included in this meta-analysis. By comparing the highest versus the lowest categories of vitamin C intake, we found that dietary vitamin C was statistically correlated with the risk of hip fracture [overall OR = 0.73, 95% CI = 0.55-0.97, I ² = 69.1%]. A linear dose-response association showed that the increase with vitamin C intake of 50 mg/day statistically reduced by 5% (OR = 0.95, 95% CI 0.91-1.00, P = 0.05) the risk of hip fracture.

CONCLUSIONS

In conclusion, the results of current meta-analysis strongly support that increasing dietary vitamin C intake can decrease the risk of hip fracture. In order to verify the association of vitamin C intake and hip fracture risk, further well-designed largely randomized controlled trials (RCTs) are needed.

Heart structural remodeling in a mouse model of Duchenne cardiomyopathy revealed using optical polarization tractography [Invited]

We investigated the heart structural remodeling in the mdx4cv mouse model of Duchenne cardiomyopathy using optical polarization tractography. Whole heart tractography was obtained in freshly dissected hearts from six mdx4cv mice. Six hearts from C57BL/6J mice were also imaged as the normal control. The mdx4cv hearts were significantly larger than the control hearts and had significantly higher between-subject variations in myofiber organization. While both strains showed classic cross-helical fiber organization in the left ventricle, the rate of the myocardial fiber orientation change across the heart wall was significantly altered in the right ventricle of the mdx4cv heart.

Investigation of the Relationship Between Flatfoot and Patellar Subluxation in Adolescents

Patellar subluxation is common in adolescents, and a variety of factors are related to this condition, with valgus of the knee joint an important factor. The results of many studies suggest that flatfoot can cause an abnormality of the lower limb power line. Structural abnormalities of the foot caused by the high stresses exerted by body weight can lead to structural deformity of the knee and can also cause knee valgus. Screening for foot problems can help determine the risk of patellar subluxation, and early intervention can lessen the incidence of this condition. The purpose of the present study was to investigate the effects of flatfoot on the structure and function of the knees and, especially, the risk of patellar subluxation. A total of 72 participants were recruited for this cross-sectional study. The mean age at examination was 15.4 ± 4.0 (range 9 to 22) years. The measured parameters were heel valgus angle, arch index, and quadriceps angle (Q-angle). Overall, the mean values of the heel valgus angle, arch index, and Q-angle were 5.9° ± 2.4° (range 1° to 11°), 0.33 ± 0.07 (range 0.23 to 0.46), and 19.1° ± 3.5° (range 9° to 26°), respectively. The Q-angle was directly associated with the heel valgus angle (r = 0.818, p < .001) and arch index (r = 0.655, p < .001). We found that flatfoot can affect the morphology of the knee joint and increase the risk of patellar subluxation.

Mapping 3D fiber orientation in tissue using dual-angle optical polarization tractography

Optical polarization tractography (OPT) has recently been applied to map fiber organization in the heart, skeletal muscle, and arterial vessel wall with high resolution. The fiber orientation measured in OPT represents the 2D projected fiber angle in a plane that is perpendicular to the incident light. We report here a dual-angle extension of the OPT technology to measure the actual 3D fiber orientation in tissue. This method was first verified by imaging the murine extensor digitorum muscle placed at various known orientations in space. The accuracy of the method was further studied by analyzing the 3D fiber orientation of the mouse tibialis anterior muscle. Finally we showed that dual-angle OPT successfully revealed the unique 3D "arcade" fiber structure in the bovine articular cartilage.

Optical polarization tractography revealed significant fiber disarray in skeletal muscles of a mouse model for Duchenne muscular dystrophy

Optical polarization tractography (OPT) was recently developed to visualize tissue fiber architecture with cellular-level resolution and accuracy. In this study, we explored the feasibility of using OPT to study muscle disease in the mdx4cv mouse model of Duchenne muscular dystrophy. The freshly dissected tibialis anterior muscles of mdx4cv and normal mice were imaged. A "fiber disarray index" (FDI) was developed to quantify the myofiber disorganization. In necrotic muscle regions of the mdx4cv mice, the FDI was significantly elevated and can be used to segment the 3D necrotic regions for assessing the overall muscle damage. These results demonstrated the OPT's capability for imaging microscopic fiber alternations in muscle research.

Cognitive impairments associated with periventricular white matter hyperintensities are mediated by cortical atrophy

BACKGROUND

Previous studies have shown that white matter lesions (WMLs) is an important risk factor for cognitive impairment, but the underlying mechanisms have not been clarified.

OBJECTIVE

We tested the hypothesis that the cognitive impairments associated with periventricular white matter hyperintensities (PWMHs) on magnetic resonance imaging (MRI) would be mediated by the cortical thinning of corresponding area.

METHOD

Sixteen stroke- and dementia-free subjects with PWMHs and 16 healthy control subjects were enrolled in this study. All participants underwent an examination of cognition, MRI-based cortical thickness measurement and a MRI-DTI scan. Then, the possible relationships among cognitive impairments, PWMHs and the topography of cortical thinning were analyzed.

RESULTS

Comparing with the controls, the cognitive tests of the subjects with PWMHs showed significant decline in the domains of verbal fluency and executive function. After accounting for age, gender, years of education, and treatable vascular risk factors related to cognitive performance, cortical thickness had an independent influence on the cognitive impairments, especially in the frontal pole, orbitofrontal cortex, superior and middle frontal gyrus, superior and middle temporal gyrus, insula, and cuneus.

CONCLUSIONS

Our results suggest that the association between PWMHs and cognitive impairments is mediated by cortical thinning.

Histology validation of mapping depth-resolved cardiac fiber orientation in fresh mouse heart using optical polarization tractography

Myofiber organization in cardiac muscle plays an important role in achieving normal mechanical and electrical heart functions. An imaging tool that can reveal microstructural details of myofiber organization is valuable for both basic research and clinical applications. A high-resolution optical polarization tractography (OPT) was recently developed based on Jones matrix optical coherence tomography (JMOCT). In this study, we validated the accuracy of using OPT for measuring depth-resolved fiber orientation in fresh heart samples by comparing directly with histology images. Systematic image processing algorithms were developed to register OPT with histology images. The pixel-wise differences between the two tractographic results were analyzed in details. The results indicate that OPT can accurately image depth-resolved fiber orientation in fresh heart tissues and reveal microstructural details at the histological level.

Relationship between expression of human gingival beta-defensins and levels of periodontopathogens in subgingival plaque

BACKGROUND AND OBJECTIVE

Human beta-defensins (hBDs) are a group of antimicrobial peptides important in epithelial innate immunity, and their differential expression is associated with periodontal diseases. The aim of this study was to explore relationships among hBDs, total subgingival bacteria and periodontopathogens in healthy subjects and in patients with chronic periodontitis.

MATERIAL AND METHODS

The periodontal clinical parameters of 29 healthy subjects and 25 patients with chronic periodontitis were recorded. The relative expression of hBD1, hBD2 and hBD3 genes in gingival biopsies was measured using real-time PCR. The numbers of total bacteria and of Treponema denticola, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum and Tannerella forsythia in subgingival plaque were quantified by real-time PCR. Data were analyzed using the Mann-Whitney U-test and Spearman's rank correlation test.

RESULTS

No significant differences in expression of the hBD genes were found between the group of healthy subjects and the group of patients with chronic periodontitis. Total bacteria and T. denticola were detected in all participants. F. nucleatum and T. forsythia were detected in all patients with chronic periodontitis and in 86.21% and 51.72%, respectively, of healthy volunteers. P. gingivalis and A. actinomycetemcomitans were detected in 24.14% and 17.24%, respectively, of the healthy group and in 84.00% and 12.00%, respectively, of the chronic periodontitis group. The prevalence of all bacteria, except A. actinomycetemcomitans, was significantly higher in the group of patients with chronic periodontitis than in the group of healthy subjects (p < 0.05). A significant, negative correlation was observed between total bacteria and hBD-2 (r = -0.384, p = 0.011). Upon analyzing the data in different groups, total bacteria and hBD-2 were significantly correlated (r = -0.492, p = 0.026) only in the group of healthy subjects.

CONCLUSION

The negative correlations between hBD-2 and total bacteria, especially in the group of healthy subjects, indicate that hBDs may play an important role by limiting an increase of bacterial load at the initial stage of periodontitis.

Functional outcome of limb-salvage surgery with shoulder abduction brace for bone tumors around the shoulders

BACKGROUND

The current trend is toward salvage of the extremity after tumor excision without compromising the extent of resection for bone tumor around the shoulders.

OBJECTIVES

The aim of this study was to evaluate functional outcome of patients treated with limb-salvage surgeries combined with shoulder abduction braces.

METHODS

Thirty-six patients with bone tumors around the shoulders, who had limb-sparing resection and reconstruction performed with a shoulder abduction brace, were retrospectively reviewed. Allograft transplantation and rigid internal fixation was performed in 22 patients and artificial prosthetic replacement was performed in 14 patients. Functional evaluation was performed based on the Musculoskeletal Tumour Society (MSTS) scoring system.

RESULTS

The overall survival was 78.8% (26/33) at 2 years. The mean final functional score was (81.2 ± 19.6%). The MSTS of patients treated by allograft transplantation and prosthetic replacement were (79.4 ± 15.3%) and (81.9 ± 18.1%), respectively. The MSTS scores differed only slightly between these two groups (P > 0.05). All the patients regained good ROM of the shoulder joints.

CONCLUSIONS

Satisfactory functional outcomes can be obtained by limb-salvage surgery for bone tumor around the shoulder. Postoperatively shoulder crutches with shoulder abduction brace are encouraged as the aid of reconstruction of shoulder joint function.

Regulation of differentiation in trabecular bone‑derived mesenchymal stem cells by T cell activation and inflammation

Mesenchymal stem cells (MSCs) are multipotent stem cells with the ability to migrate to sites of inflammation and injury, where they participate in tissue regeneration and repair. The present study aimed to investigate the effects of T cell activation and inflammation on the differentiation of MSCs. Human trabecular bone‑derived MSCs were isolated from patients undergoing total hip replacement, and T cells were isolated and purified from peripheral blood mononuclear cells (PBMCs) using CD3 MicroBeads. MSCs were co‑cultured with activated T cells to mimic the inflammatory microenvironment. MTS assay was used to detect cell proliferation.qRT‑PCR, western blotting, histology and immunohistochemical staining were used to detect the adipo‑/osteo‑specific gene expression and the relative signaling pathway. The MTS results showed that higher concentrations of T cells significantly increased the proliferation of MSCs. Expression of the inflammatory gene IL‑6 was upregulated, while expression of IL‑10 and INFγ was downregulated in MSCs exposed to activated T cells. The results also showed that PHA‑activated T cells significantly upregulated the expression of PPARγ and FABP4 (adipo‑specific genes) in MSCs, but no difference was noted in the expression of RUNX2, osteocalcin and ALP (osteo‑specific genes) at the protein level. T cell treatment and inflammation inhibited the protein expression of TGF‑β1 and the phosphorylation of Smad3, resulting in the weakening of the TGF‑β/Smad pathway and enhancing the adipogenic differentiation of MSCs. The results indicated that PHA‑activated T cells and inflammation could promote adipogenesis without affecting the late stage of osteogenesis of MSCs, by increasing the expression of key adipogenic genes through TGF‑β/Smad3 signaling.

Sci-Fri AM: Imaging - 09: Serial estimation of cross-talk for correction in dual-isotope imaging with dynamic tracers

The recent radioisotope shortage has led to interest in non-Tc99m-based tracers. We have developed a novel I-123-labelled myocardial perfusion imaging tracer. We compare the I123-tracer to the clinical standard of Tc99m tetrofosmin in vivo in a rat model using a small-animal SPECT/CT camera. SPECT distinguishes different isotopes based on the different energies of the emitted gamma rays and thus allows simultaneous comparison of two tracer distributions in the same animal. Dual-isotope imaging is complicated by cross-talk between the energy windows of the isotopes. Standard energy-window-based correction methods are difficult to employ because of the proximity in energy of Tc99m (140keV) and I123 (159keV). Imaging the second tracer's energy window prior to its injection provides an estimate of the cross-talk. However, this estimate is only accurate if the tracer distribution is static. We use serial imaging prior to the introduction of the second tracer to estimate the dynamics of the first tracer and interpolate the cross-talk images to provide a more accurate correction. We used rat models of myocardial disease (n=3). I123 tracer was injected and imaged for one hour at 20min intervals. The Tc99m tetrofosmin was then injected and 30min later, a dual-isotope image was obtained. The impact of this approach is assessed by comparing the differences in the Tc99m-tetrofosmin image using this method with correction by simple correction for physical decay. The interpolative approach improves the accuracy of the correction by 2%-5% and thereby enhances the comparison of the two tracers.

[Initial therapeutic evaluation of arthroscopic reconstruction of anterior and posterior cruciate ligament injury with anterior tibialis tendon allograft]

OBJECTIVE

To study the operative procedure and effect of arthroscopic reconstruction of both anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) with anterior tibialis tendon allograft.

METHODS

From February 2005 to July 2006, 10 cases of both ACL and PCL rupture were reconstructed with anterior tibialis tendon allograft, including 7 men and 3 women, aging 18-45 years with an average of 30.2 years. The locations were left knee in 6 cases and right knee in 4 cases. All of them had identified trauma history. The disease course was about 1-3 weeks (mean 1.8 weeks). Both ACL and PCL were reconstructed under arthroscope with allograft anterior tibialis tendon of 26-28 cm in length and immobilization with extention position brace was given for 4 weeks after operation. The active flex knee exercise was done from 0-90 degrees at 4 weeks and more than 90 degrees at 6 weeks.

RESULTS

All operations were finished successfully, there were no blood vessel and nerve injury. The operative time was 90-110 minutes (mean 100 minutes). The wound healed by first intention and no early complication occurred. Ten cases were followed up for 12 months to 15 months with an average of 13.5 months. Thier gait was normal, knee activity degree was 0-135 degrees. The anterior drawing tests and media and lateral stress tests were negative after operation in 10 cases; and the posterior drawing tests were negative in 8 cases and 2 cases was at grade I. Hydra arthrosis of knee occurred in 2 cases and was cured after remove of fluid and injection of sodium hyaluronate. The Lysholm knee function score was increases from 24.89 +/- 5.39 before operation to 96.00 +/- 4.59 at 12 months after operation, showing significant difference (P < 0.05).

CONCLUSION

Arthroscopic reconstruction of both ACL and PCL with anterior tibialis tendon allograft has the advantages of short operation time, less complications and good clinical effects.

A combination of granulocyte colony-stimulating factor and stem cell factor ameliorates steroid-associated osteonecrosis in rabbits

OBJECTIVE

Bone marrow-derived stem cells (BMSC) have been highlighted for the treatment of osteonecrosis (ON) before collapse of the femoral head. In our study, the potential of granulocyte colony-stimulating factor/stem cell factor (G-CSF/SCF)-mobilized BMSC to repair steroid-associated ON was assessed in rabbits.

METHODS

ON was induced by low-dose lipopolysaccharide and subsequent pulsed high-dose methylprednisolone. Rabbits in the treated group were subjected to subcutaneous injections of G-CSF at a dose of 100 microg/kg and SCF 25 microg/kg per day for 5 days; rabbits in the control group were given saline. Blood samples were collected and serum osteocalcin was detected by ELISA. Radiological analysis was performed by magnetic resonance imaging (MRI). Then bilateral femora and humeri were harvested and processed to paraffin sections and hard-tissue sections for immunohistochemical, histologic, and histomorphometric analysis.

RESULTS

. The mean number of leukocytes and relative numbers of mononuclear cells increased significantly after mobilization. All rabbits displayed a marked increase in osteocalcin protein expression in response to G-CSF/SCF. MRI scans showed a reactive interface between the necrotic and reparative zones after G-CSF/SCF administration. Quantitative analysis showed that new vessel formation was 3.3-fold greater and vessel density was 2.6-fold greater in the treatment group than the control group. The histologic and histomorphometric analysis revealed that the new bone volume was significantly higher in the G-SCF/SCF group than in the control group at 4 weeks.

CONCLUSION

G-CSF/SCF-induced mobilization of BMSC in the necrotic foci may represent a promising strategy for promoting functional bone repair of early-stage ON.

Identification of aberrant forms of alkaline sphingomyelinase (NPP7) associated with human liver tumorigenesis

Alkaline sphingomyelinase (alk-SMase) is expressed in the intestine and human liver. It may inhibit colonic tumorigenesis, and loss of function mutations have been identified in human colon cancer. The present study investigates its expression in human liver cancer. In HepG2 liver cancer cells, RT–PCR identified three transcripts with 1.4, 1.2 and 0.4 kb, respectively. The 1.4 kb form is the wild-type cDNA with five translated exons, the 1.2 kb product lacks exon 4 and the 0.4 kb form is a combination of exons 1 and 5. Genomic sequence showed that these aberrant transcripts were products of alternative splicing. Transient expression of the 1.2 kb form showed no alk-SMase activity. In HepG2 cells, the alk-SMase activity is low in monolayer condition and increased with cell polarisation. Coexistence of 1.4 and 1.2 kb forms was also identified in one hepatoma biopsy. GenBank search identified a cDNA clone from human liver tumour, which codes a protein containing full length of alk-SMase plus a 73-amino-acid tag at the N terminus. The aberrant form was translated by an alternative starting codon upstream of the wild-type mRNA. Expression study showed that linking the tag markedly reduced the enzyme activity. We also analysed human liver biopsy samples and found relatively low alk-SMase activity in diseases with increased risk of liver tumorigenesis. In conclusion, expression of alk-SMase is changed in hepatic tumorigenesis, resulting in loss or marked reduction of the enzyme function.

Systemic AAV-9 transduction in mice is influenced by animal age but not by the route of administration

Adeno-associated virus (AAV) serotype-9 (AAV-9) has attracted great attention as an optimal vehicle for body-wide gene delivery. Here we examined the effect of animal age (newborn vs adult) and the route of administration (intravenous vs intra-arterial) on systemic AAV-9 transduction. We delivered an alkaline phosphatase (AP) reporter gene AAV vector (AV.RSV.AP) to either newborn (via either the facial vein or the left ventricular cavity) or adult (via tail vein) C57Bl/10 mice. At 12 weeks' postinfection, we examined the AP expression. We observed efficient transduction in multiple skeletal muscles and the heart, irrespective of the age or delivery route. However, the soleus muscle, which consists mainly of slow-twitch myofibers, was poorly transduced. Besides striated muscle, we also found consistent high-level transduction in the lung. Abundant AP-positive cells were seen in alveolar cells and vasculature, but not in bronchioles. Interestingly, several organs demonstrated an age-dependent profile. In particular, the aorta, liver and kidney were preferentially transduced in adult mice while the inner layer of retina was strongly transduced only following the neonatal administration. Taken together, our results demonstrate the robustness of intravascular AAV-9 delivery for muscle and lung gene therapy applications. The unique expression patterns in the aorta, liver, kidney and retina call for special attention when designing AAV-9 gene therapy applications for these organs.

Protective effect of niacinamide on interleukin-1β-induced annulus fibrosus type II collagen degeneration in vitro

The protective effect of niacinamide on interleukin-1beta (IL-1beta)-induced annulus fibrosus (AF) type II collagen degeneration in vitro and the mechanism were investigated. Chiba's intervertebral disc (IVD) culture models in rabbits were established and 48 IVDs from 12 adult Japanese white rabbits were randomly divided into 4 groups: normal control group, niacinamide-treated group, type II collagen degneration group (IL-1beta) and treatment group (niacinamide+IL-1beta). After culture for one week, AFs were collected for inducible nitric oxide synthase (iNOS), cysteine containing aspartate specific protease-3 (Caspase-3) and type II collagen immunohistochemical examination, and type II collagen reverse transcription polymerase chain reaction (RT-PCR). The results showed that rate of iNOS positive staining AF cells in the 4 groups was 17.6%, 10.9%, 73.9% and 19.3% respectively. The positive rate in treatment group was significantly lower than in the type II collagen degeneration group (P<0.01). Rate of Caspase-3 positive staining AF cells in the 4 groups was 3.4%, 4.2%, 17.6% and 10.3% respectively. The positive rate in treatment group was lower than in the type II collagen degeneration group (P<0.01). Type II collagen staining demonstrated that lamellar structure and continuity of collagen in treatment group was better reversed than in the degeneration group. RT-PCR revealed that the expression of type II collagen in treatment group was significantly stronger than that in type II collagen degeneration group (P<0.01). It was concluded that niacinamide could effectively inhibit IL-1beta stimulated increase of iNOS and Caspase-3 in AF, and alleviate IL-1beta-caused destruction and synthesis inhibition of type II collagen. Niacinamide is of potential for clinical treatment of IVD degeneration.

The mechanisms of uremic serum-induced expression of bone matrix proteins in bovine vascular smooth muscle cells

We have previously found that uremic human serum upregulates RUNX2 in vascular smooth muscle cells (VSMCs), and that RUNX2 is upregulated in areas of vascular calcification in vivo. To confirm the role of RUNX2, we transiently transfected a dominant-negative RUNX2 (DeltaRUNX2) construct in bovine vascular smooth muscle cells (BVSMCs). Blocking RUNX2 transcriptional activity significantly decreased uremic serum induced alkaline phosphatase (ALP) activity (268+/-34 vs 188+/-9.5 U/g protein, P<0.05) and osteocalcin expression (172+/-17 vs 125+/-9 ODU, P<0.05). To determine the mechanism by which uremic serum upregulates RUNX2, we examined cell signaling pathways. BVSMCs were incubated in the presence or absence of inhibitors and RUNX2 expression and ALP activity were determined. The results demonstrate that the cyclic AMP (cAMP)/protein kinase A (PKA), but not protein kinase C, signaling pathway is involved in uremic serum-induced RUNX2 expression and ALP activity in BVSMCs. To examine potential uremic 'toxins', we measured bone morphogenetic protein (BMP)-2 concentration and found that uremic serum contained increased BMP-2 (uremic serum=169+/-33 pg/ml, normal serum=117+/-15 pg/ml, P<0.05). The incubation of BVSMCs with noggin, an inhibitor of BMP, decreased RUNX2 expression. In addition, BMP-2 secretion progressively increased during calcification and uremic serum enhanced its secretion compared to normal serum. In conclusion, this study demonstrates that RUNX2 transcriptional activity is critical in uremic serum-induced bone matrix protein expression in BVSMCs and that the cAMP/PKA pathway is involved. BMP-2 is also increased in uremic serum and can upregulate RUNX2 and calcification in vitro in VSMCs.

Functional role of amino terminus in ClC-3 chloride channel regulation by phosphorylation and cell volume

AIM

This study investigated the functional role of the ClC-3 amino-terminus in channel regulation in response to changes in cell volume.

METHODS

Wild-type sClC-3 tagged with a green fluorescence protein (GFP) at the C-terminus was used as a template to construct a number of deletion mutants which were functionally expressed in NIH-3T3 cells. Whole cell and single channel patch-clamp electrophysiology was used to determine the functional properties of heterologously expressed channels.

RESULTS

The first 100 amino acids of the ClC-3 N-terminus were removed and the truncated channel (sClC-3DeltaNT) was functionally expressed. Immunocytochemistry confirmed membrane expression of both wtsClC-3 and sClC-3DeltaNT channels in NIH/3T3 cells. sClC-3DeltaNT yielded constitutively active functional channels, which showed no response to protein kinase C or changes in cell volume. Deletion of a cluster of negatively charged amino acids 16-21 (sClC-3Delta16-21) within the N-terminus also yielded a constitutively active open channel phenotype, indicating these amino acids are involved in the N-type regulation. Intracellular delivery of a thiol-phosphorylated peptide corresponding to N-terminal residues 12-61 (NT peptide) markedly inhibited sClC-3DeltaNT whole-cell and single-channel currents, further confirming the essential role of the N-terminus in volume regulation of channel activity.

CONCLUSIONS

These data strongly suggest the N-terminus of sClC-3 channels acts as a blocking particle inhibiting the flow of anions through the channel pore. This 'N-type' regulation of sClC-3 channels may be an important transducing mechanism linking changes in cell volume and channel protein phosphorylation to channel gating.

The use of calcaneal anatomic plate in arthroscopically-assisted open reduction and internal fixation of intra-articular calcaneal fractures

To discuss and evaluate the method and effect of using calcaneal anatomic plate in treatment of intra-articular fractures of the calcaneus with assistant of arthroscope, 86 intra-articular fractures of the calcaneus in 78 patients were reduced by open reduction, and rigid fixation was made with calcaneal anatomic plate under assistant of arthroscope. The average follow-up duration was 18 months (range 12-30 months). The effect of treatment was evaluated according to AOFAS and X-ray before and after operation. The results showed that 86 patients have obtained satisfactory reduction according to X-ray, and there was significant difference before and after operation (P < 0. 01), the total excellent and fine rate was 91.86%. Treating intra-articular fractures of the calcaneus with calcaneal anatomic plate under arthroscope may provide more chance to achieve anatomical reconstruction, which can lead to satisfied recovery of function and few complication.

Up-regulation of niacinamide in intervertebral disc aggrecanin vitro

The regulatory effects of niacinamide (Nia) on intervertebral disc (IVD) aggrecan in vitro was investigated. Chiba's 10 ng/mL interleukin-1 (IL-1)-induced rabbit IVD degeneration model in vitro was established. 0.5, 0.25 and 0.05 mg/mL Nia was added to normal and degenerated IVDs for intervention. On the first and second week after intervention, safranin O-fast green staining intensity and glycosaminoglycan (GS) content were measured. The expression of aggrecan core protein was detected by RT-PCR. The results showed: (1) After treatment with 0.5 mg/mL Nia for one week, the GS content in nucleus pulposus (NP) was increased by 44.8% as compared with control group (P < 0 01); The GS content in IL-1 induction groups was increased with the increase of Nia concentrations: After treatment with 0.5 mg/mL for one week, the GS content in NP was increased by 68.3% as compared with control group (P < 0.01). After two weeks, GS content in NP and fibrous rings was still higher than in control group at the same period (P < 0.01) and untreated group (P < 0.01). (2) Safranin O-fast green staining revealed that with the increase of Nia concentrations, staining density in NP and fibrous rings was increased and histological structure damage to IVDs by IL-1beta was alleviated. (3) RT-PCR showed that the expression of core protein gene in IL-1beta-induced degenerated IVDS was increased with the increase of Nia concentrations. It was concluded that under conditions in vitro, Nia could up-regulate the expression of aggrecan in IVDs and protect IVDs from IL-1beta-induced degeneration at least partially, which offers a potential choice for IVD degeneration clinical therapy.

Molecular Dynamics Study of Translational and Rotational Diffusion in Liquid Ortho-terphenyl

NVT molecular dynamics simulations were performed on liquid o-terphenyl as a function of temperature in the range 320-480 K. Computed translational diffusion coefficients displayed the non-Arrhenius behavior expected of a fragile glass-forming liquid and were in good, semiquantitative agreement with experimental results. Rotational correlation functions calculated for various vectors within the molecule exhibited a very short time (0-1 ps) initial decay, followed by a reversal, which corresponds to free reorientation within the "solvent" cage prior to collision with a wall. Rotational correlation times of three orthogonal vectors fixed on the central benzene were close to equal at all temperatures, indicating nearly isotropic overall molecular reorientation. The average correlation times exhibited a non-Arrhenius temperature dependence and were in very good agreement with experimental values derived from 2D and 1H NMR relaxation times. Correlation times of vectors located on the lateral phenyl rings were used to calculate the "spinning" internal rotation diffusion coefficients, which were approximately twice as great as the overall rotational diffusion constants, indicating rapid internal rotation of the phenyl side groups over wide ranges of angle in the liquid.

Molecular Dynamics Study of Anisotropic Translational and Rotational Diffusion in Liquid Benzene

Equilibrium NPT and NVT molecular dynamics simulations were performed on liquid benzene over an extended range of temperature (from 260 to 360 K) using the COMPASS force field. Densities and enthalpies of vaporization (from cohesive energy densities) were within 1% of experiment at all temperatures. tumbling and spinning rotational diffusion coefficients, D(perpendicular) and D(parallel), computed as a function of temperature, agreed qualitatively with the results of earlier reported experimental and computational investigations. Generally, it was found that D(parallel)/D(perpendicular) approximately 1.4-2.5 and the activation energy for tumbling was significantly greater than for spinning about the C6 axis [Ea(D(perpendicular)) = 8.1 kJ mol(-1) and Ea(D(parallel)) = 4.5 kJ mol(-1)]. Calculated translational diffusion coefficients were found to be in quantitative agreement with experimental values at all temperatures [deviations were less than the scatter between different reported measurements]. In addition, translational diffusion coefficients were computed in the molecule-fixed frame to yield values for Dxy (diffusion in the plane of the molecule) and Dz (diffusion perpendicular to the plane). It was found that the ratio Dxy/Dz approximately 2.0, and that the two coefficients have roughly equal activation energies. This represents the first atomistic molecular dynamics study of translational diffusion in the molecular frame.

Adenovirus-mediated delivery of catalase to retinal pigment epithelial cells protects neighboring photoreceptors from photo-oxidative stress

Oxidative stress is involved in the pathogenesis of many diseases. Overexpression of antioxidant enzymes by gene therapy may protect tissues from oxidative damage. Because the reactive oxygen species hydrogen peroxide can diffuse across cell membranes, we hypothesized that overexpression of the antioxidant catalase within certain cells might protect neighboring cells. To test this hypothesis, we transduced retinal pigment epithelial (RPE) cells in vitro and in vivo with adenovirus carrying the catalase gene (Ad.CMV.catalase). After transduction of only a subset of RPE cells in vitro, all cells in the culture were protected from exogenous hydrogen peroxide. Similarly, in vivo, eyes injected with Ad. CMV. catalase had high catalase levels in the RPE, which protected the adjacent photoreceptors from light damage and reduced photoreceptor oxidative stress as measured by the markers 4-hydroxynonenal and nitrotyrosine. Both in vitro and in vivo, gene therapy with Ad. CMV. catalase protected neighboring cells from oxidative stress-induced terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) positivity. The data provide a paradigm for antioxidant gene therapy with catalase, designed to protect not only transduced cells, but also neighboring cells.

Imaging single cardiac ryanodine receptor Ca2+ fluxes in lipid bilayers

In this and an accompanying report we describe two steps, single-channel imaging and channel immobilization, necessary for using optical imaging to analyze the function of ryanodine receptor (RyR) channels reconstituted in lipid bilayers. An optical bilayer system capable of laser scanning confocal imaging of fluo-3 fluorescence due to Ca2+ flux through single RyR2 channels and simultaneous recording of single channel currents was developed. A voltage command protocol was devised in which the amplitude, time course, shape, and hence the quantity of Ca2+ flux through a single RyR2 channel is controlled solely by the voltage imposed across the bilayer. Using this system, the voltage command protocol, and concentrations of Ca2+ (25-50 mM) that result in saturating RyR2 Ca2+ currents, proportional fluo-3 fluorescence was recorded simultaneously with Ca2+ currents having amplitudes of 0.25-14 pA. Ca2+ sparks, similar to those obtained with conventional microscope-based laser scanning confocal systems, were imaged in mouse ventricular cardiomyocytes using the optical bilayer system. The utility of the optical bilayer for systematic investigation of how cellular factors extrinsic to the RyR2 channel, such as Ca2+ buffers and diffusion, alter fluo-3 fluorescent responses to RyR2 Ca2+ currents, and for addressing other current research questions is discussed.