Hypermethylation and expression regulation of secreted frizzled-related protein genes in colorectal tumor

AIM: To investigate the functions of promoter hyper- methylation of secreted frizzled-related proteins (sFRPs) genes in colorectal tumorigenesis and progression. METHODS: The promoter hypermethylation and expression of sFRP genes in 72 sporadic colorectal carcinomas, 33 adenomas, 18 aberrant crypt foci (ACF) and colorectal cancer cell lines RKO, HCT116 and SW480 were detected by methylation-specific PCR and reverse transcription PCR, respectively. RESULTS: None of the normal colorectal mucosa tissues showed methylated bands of any of four sFRP genes. sFRP1, 2, 4 and 5 were frequently methylated in colorectal carcinoma, adenoma and ACF (sFRP1 > 85%, sFRP2 >75%, sFRP5 > 50%), and the differences between three colorectal tissues were not significant (P > 0.05). Methylation in colorectal tumors was more frequent than in normal mucosa and adjacent normal mucosa. The mRNA of sFRP1-5 genes was expressed in all normal colorectal mucosa samples. Expression of sFRP1, 2, 4 and 5 and sFRP1 , 2 and 5 was downregulated in carcinoma and adenoma, respectively. The downregulation of sFRP2, 4 and 5 was more frequent in carcinoma than in adenoma. Expression of sFRP3 which promoter has no CpG island was downregulated in only a few of colorectal tumor samples (7/105). The downregulation of sFRP1, 2, 4 and 5 expression was significantly associated with promoter hypermethylation in colorectal tumor. After cells were treated by DAC/TSA combination, the silenced sFRP mRNA expression could be effectively re-expressed in colorectal cancer cell lines.CONCLUSION: Hypermethylation of sFRP genes is acommon early event in the evolution of colorectal tumor, occurring frequently in ACF, which is regarded as the earliest lesion of multistage colorectal carcinogenesis. It appears to functionally silence sFRP genes expression. Methylation of sFRP1, 2 and 5 genes might serve as indicators for colorectal tumor.

Detection of promoter hypermethylation of Wnt antagonist genes in fecal samples for diagnosis of early colorectal cancer

AIM:To investigate the feasibility of detecting aberrantly hypermethylated Wnt-antagonist gene promoters(SFRP2 and WIF-1)in fecal DNA as non-invasive biomarkers for early colorectal cancer(CRC).METHODS:The methylation-specific polymerase chain reaction assay was performed to blindly analyze the methylation status of SFRP2 and WIF-1 gene promoters in fecal samples from 48 subjects with CRC,35 with adenomas,32 with hyperplastic polyps and 30 endoscopically normal subjects.Additionally,we comparedthe diagnostic efficiency of measuring the hypermethylated SFRP2 and WIF-1 genes in the feces to the fecal occult blood test(FOBT)for the early detection of CRC.RESULTS:Hypermethylated SFRP2 was detected in the feces of 56.3%(27/48)of CRC cases,51.4%(18/35)of adenoma cases and 12.5%(4/32)of patients with hyperplastic polyps.The hypermethylation of WIF-1was detected in 60.4%(29/48),45.7%(16/35)and18.7%(6/32)of fecal samples from CRC,adenoma and hyperplastic polyp patients,respectively.At least one hypermethylated gene was detected in 81.3%(39/48)of CRC and 65.7%(23/35)of adenoma samples.In contrast,only a hypermethylated WIF-1 gene was detected in one case of normal fecal samples.Moreover,no significant associations were observed between SFPR2 and WIF-1 hypermethylation and clinicopathological features.Additionally,81.8%of CRC cases diagnosed as Dukes A stage or advanced adenomas had at least one hypermethylated gene detected,while the detection rate with the FOBT was only 31.8%(P<0.001).CONCLUSION:Hypermethylated SFRP2 and WIF-1genes in fecal DNA are novel and promising molecular biomarkers that have great diagnostic potential for early CRC.

Accuracy of early detection of colorectal tumours by stool methylation markers:A meta-analysis

AIM:To evaluate the accuracy of methylation of genes in stool samples for diagnosing colorectal tumours.METHODS:Electronic databases including PubMed,Web of Science,Chinese Journals Full-Text Database and Wanfang Journals Full-Text Database were searched to find relevant original articles about methylated genes to be used in diagnosing colorectal tumours. A quality assessment of diagnostic accuracy studies tool(QADAS) was used to evaluate the quality of the included articles,and the Meta-disc 1.4 and SPSS 13.0 software programs were used for data analysis.RESULTS:Thirty-seven articles met the inclusion criteria,and 4484 patients were included. The sensitivity and specificity for the detection of colorectal cancer(CRC) were 73%(95%CI:71%-75%) and 92%(95%CI:90%-93%),respectively. For adenoma,the sensitivity and specificity were 51%(95%CI:47%-54%) and 92%(95%CI:90%-93%),respectively. Pooled diagnostic performance of SFRP2 methylation for CRC provided the following results:the sensitivity was 79%(95%CI:75%-82%),the specificity was 93%(95%CI:90%-96%),the diagnostic OR was 47.57(95%CI:20.08-112.72),the area under the curve was 0.9565. Additionally,the results of accuracy of SFRP2 methylation for detecting colorectal adenomas were as follows:sensitivity was 43%(95%CI:38%-49%),specificity was 94%(95%CI:91%-97%),the diagnostic OR was 11.06(95%CI:5.77-21.18),and the area under the curve was 0.9563.CONCLUSION:Stool-based DNA testing may be useful for noninvasively diagnosing colorectal tumours and SFRP2 methylation is a promising marker that has great potential in early CRC diagnosis.

Three-dimensional visualization of the functional fascicular groups of a long-segment peripheral nerve

The three-dimensional（3D） visualization of the functional bundles in the peripheral nerve provides direct and detailed intraneural spatial information. It is useful for selecting suitable surgical methods to repair nerve defects and in optimizing the construction of tissue-engineered nerve grafts. However, there remain major technical hurdles in obtaining, registering and interpreting 2D images, as well as in establishing 3D models. Moreover, the 3D models are plagued by poor accuracy and lack of detail and cannot completely reflect the stereoscopic microstructure inside the nerve. To explore and help resolve these key technical problems of 3D reconstruction, in the present study, we designed a novel method based on re-imaging techniques and computer image layer processing technology. A 20-cm ulnar nerve segment from the upper arm of a fresh adult cadaver was used for acetylcholinesterase（ACh E） staining. Then, 2D panoramic images were obtained before and after ACh E staining under the stereomicroscope. Using layer processing techniques in Photoshop, a space transformation method was used to fulfill automatic registration. The contours were outlined, and the 3D rendering of functional fascicular groups in the long-segment ulnar nerve was performed with Amira 4.1 software. The re-imaging technique based on layer processing in Photoshop produced an image that was detailed and accurate. The merging of images was accurate, and the whole procedure was simple and fast. The least square support vector machine was accurate, with an error rate of only 8.25%. The 3D reconstruction directly revealed changes in the fusion of different nerve functional fascicular groups. In conclusion. The technique is fast with satisfactory visual reconstruction.

Analysis of transcriptome sequencing of sciatic nerves in Sprague-Dawley rats of different ages

An aging-induced decrease in Schwann cell viability can affect regeneration following peripheral nerve injury in mammals. It is therefore necessary to investigate possible age-related changes in gene expression that may affect the biological function of peripheral nerves. Ten 1-week-old and ten 12-month-old healthy male Sprague-Dawley rats were divided into young（1 week old） and adult（12 months old） groups according to their ages. mRNA expression in the sciatic nerve was compared between young and adult rats using next-generation sequencing（NGS） and bioinformatics（n = 4/group）. The 18 groups of differentially expressed mRNA（DEmRNAs） were also tested by quantitative reverse transcription polymerase chain reaction（n = 6/group）. Results revealed that（1） compared with young rats, adult rats had 3608 groups of DEmRNAs. Of these, 2684 were groups of upregulated genes, and 924 were groups of downregulated genes. Their functions mainly involved cell viability, proliferation, differentiation, regeneration, and myelination.（2） The gene with the most obvious increase of all DEmRNAs in adult rats was Thrsp（log2 FC = 9.01, P 〈 0.05）, and the gene with the most obvious reduction was Col2 a1（log2 FC = -8.89, P 〈 0.05）.（3） Gene Ontology analysis showed that DEmRNAs were mainly concentrated in oligosaccharide binding, nucleotide-binding oligomerization domain containing one signaling pathway, and peptide-transporting ATPase activity.（4） Analysis using the Kyoto Encyclopedia of Genes and Genomes showed that, with increased age, DEmRNAs were mainly enriched in steroid biosynthesis, Staphylococcus aureus infection, and graft-versus-host disease.（5） Spearman＇s correlation coefficient method for evaluating NGS accuracy showed that the NGS results and quantitative reverse transcription polymerase chain reaction results were positively correlated（rs = 0.74, P 〈 0.05）. These findings confirm a difference in sciatic nerve gene expression between adult and young rats, suggesting that, in peripheral nerves, cells and the microenvironment change with age, thus influencing the function and repair of peripheral nerves.

Digital Continuity Guarantee Approach of Electronic Record Based on Data Quality Theory

Since the British National Archive put forward the concept of the digital continuity in 2007,several developed countries have worked out their digital continuity action plan.However,the technologies of the digital continuity guarantee are still lacked.At first,this paper analyzes the requirements of digital continuity guarantee for electronic record based on data quality theory,then points out the necessity of data quality guarantee for electronic record.Moreover,we convert the digital continuity guarantee of electronic record to ensure the consistency,completeness and timeliness of electronic record,and construct the first technology framework of the digital continuity guarantee for electronic record.Finally,the temporal functional dependencies technology is utilized to build the first integration method to insure the consistency,completeness and timeliness of electronic record.

A rapid micro-magnetic resonance imaging scanning for three-dimensional reconstruction of peripheral nerve fascicles

The most common methods for three-dimensional reconstruction of peripheral nerve fascicles include histological and radiology techniques. Histological techniques have many drawbacks including an enormous manual workload and poor image registration. Micro-magnetic resonance imaging（Micro-MRI）, an emerging radiology technique, has been used to report results in the brain, liver and tumor tissues. However, micro-MRI usage for obtaining intraneural structures has not been reported. The aim of this study was to present a new imaging method for three-dimensional reconstruction of peripheral nerve fascicles by ~1T micro-MRI. Freshly harvested sciatic nerve samples from an amputated limb were divided into four groups. Two different scanning conditions（Mannerist Solution/GD-DTPA contrast agent, distilled water） were selected, and both T1 and T2 phases programmed for each scanning condition. Three clinical surgeons evaluated the quality of the images via a standardized scale. Moreover, to analyze deformation of the two-dimensional image, the nerve diameter and total area of the micro-MRI images were compared after hematoxylin-eosin staining. The results show that rapid micro-MRI imaging method can be used for three-dimensional reconstruction of the fascicle structure. Nerve sample immersed in contrast agent（Mannerist Solution/GD-DTPA） and scanned in the T1 phase was the best. Moreover, the nerve sample was scanned freshly and can be recycled for other procedures. MRI images show better stability and smaller deformation compared with histological images. In conclusion, micro-MRI provides a feasible and rapid method for three-dimensional reconstruction of peripheral nerve fascicles, which can clearly show the internal structure of the peripheral nerve.

Various changes in cryopreserved acellular nerve allografts at-80°C

The experimental design evaluated histological,mechanical,and biological properties of allogeneic decellularized nerves after cryopreservation in a multi-angle,multi-directional manner to provide evidence for long-term preservation.Acellular nerve allografts from human and rats were cryopreserved in a cryoprotectant（10% fetal bovine serum,10% dimethyl sulfoxide,and 5% sucrose in RPMI1640 medium） at-80°C for 1 year,followed by thawing at 40°C or 37°C for 8 minutes.The breaking force of acellular nerve allografts was measured using a tensile test.Cell survival was determined using L-929 cell suspensions.Acellular nerve allografts were transplanted into a rat model with loss of a 15-mm segment of the left sciatic nerve.Immunohistochemistry staining was used to measure neurofilament 200 expression.Hematoxylin-eosin staining was utilized to detect relative muscle area in gastrocnemius muscle.Electron microscopy was applied to observe changes in allograft ultrastructure.There was no obvious change in morphological appearance or ultrastructure,breaking force,or cytotoxicity of human acellular nerve allografts after cryopreservation at-80°C.Moreover,there was no remarkable change in neurofilament 200 expression,myelin sheath thickness,or muscle atrophy when fresh or cryopreserved rat acellular nerve allografts were applied to repair nerve injury in rats.These results suggest that cryopreservation can greatly extend the storage duration of acellular nerve tissue allografts without concomitant alteration of the physiochemical and biological properties of the engineered tissue to be used for transplantation.

Changes in platelet parameters and secondary brain injury in acute craniocerebral trauma

Changes in platelet parameters are important in secondary brain injury in acute craniocerebral trauma We selected 163 patients with craniocerebral trauma who were admitted within 24 hours with nonoperative therapy. Platelet parameters of 40 healthy subjects served as controls. Platelet number was decreased, while mean platelet volume and platelet distribution width values were increased, at 1 and 3 days after injury. Platelet number was lower and mean platelet volume and platelet distribution width were larger in patients with traumatic cerebral infarction and those in Glasgow Coma Scale score 〈 8 group. Platelet number was negatively correlated to volume of cerebral edema, but positively correlated to Glasgow Outcome Scale score. These data indicate that changes in platelet parameters may be utilized to indicate the state of central nervous system injury and patient prognosis .

聚合物抗污涂层的研究进展

构筑聚合物抗污涂层表面是解决生物污损的有效策略.聚合物具有耐酸碱性和易于功能化及表面修饰等优点,聚合物抗污涂层在降低生物污损对材料的影响和减少经济损失中发挥着重要作用.本文综合评述了聚合物抗污涂层的各种研究策略和研究进展,介绍了相关新型聚合物抗污涂层的成果,并展望了该领域面临的挑战.

Network Electronic Record Management Based on Linked Dat

With the rapid development of e-government,e-commerce and self-media,a large number of electronic network records have been generated on the Internet.How to archive these resources has become a focus of attention in academic circles.Based on the theory of linked data,this paper analyzes the archiving of electronic records,and proposes that the corresponding network electronic records should be collected using the theory of linked data.After the resource description framework and corresponding international standards are utilized to convert the network resources,the electronic network records are stored in common databases to solve the problem of network record archiving management.

Characterization of somatic mutations of colorectal tumor in a patient with concurrent APC and MLH1 germline mutations

The two most common inherited forms of colorectal cancer(CRC)are familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer.They are caused by germline mutations in the APC and mismatch repair genes,respectively.1 The simultaneous inheritance of both an APC gene mutation and a mismatch repair gene mutation is very rare.In this study,we reported a coinheritance of mutations in the APC and MLH1 genes in a 20-year-old patient with CRC and multiple polyposes.We described for the first time the somatic mutational profile of a colorectal tumor harboring concurrent germline mutations in the APC and MLH1 genes.

A Resource for Inactivation of MicroRNAs Using Short Tandem Target Mimic Technology in Model and Crop Plants

microRNAs (miRNAs)are endogenous small non-coding RNAs that bind to mRNAs and target them for cleavage and/or translational repression,leading to gene silencing.We previously developed short tandem target mimic (STTM)technology to deactivate endogenous miRNAs in Arabidopsis.Here,we created hundreds of STTMs that target both conserved and species-specific miRNAs in Arabidopsis,tomato,rice,and maize,providing a resource for the functional interrogation of miRNAs.We not only revealed the functions of several miRNAs in plant development,but also demonstrated that tissue-specific inactivation of a few miRNAs in rice leads to an increase in grain size without adversely affecting overall plant growth and development.RNA-seq and small RNAseq analyses of STTM156/157 and STTM165/166 transgenic plants revealed the roles of these miRNAs in plant hormone biosynthesis and activation,secondary metabolism,and ion-channel activity-associated electrophysiology,demonstrating that STTM technology is an effective approach for studying miRNA functions.To facilitate the study and application of STTM transgenic plants and to provide a useful platform for storing and sharing of information about miRNA-regulated gene networks,we have established an online Genome Browser (https://blossom.ffr.mtu.edu/designindex2.php) to display the transcriptomic and miRNAomic changes in STTMinduced miRNA knockdown plants.

Multi-shelled TiO2/Fe2TiO5 heterostructured hollow microspheres for enhanced solar water oxidation

There remains a pressing challenge in the fabrication of superior photocatalysts for light-driven water oxidation.Here,we designed and fabricated heterostructured TiO2/Fe2TiO5 hollow microspheres with single-,double-,closed-double-,triple-,and core-shell structures and different Fe/Ti molar ratios using a facile sequential templating approach.The closed-double-shelled TiO2/Fe2TiO5 hollow microspheres with 35% Fe exhibited the highest oxygen evolution reaction rate up to 375 μmol＆#183;g-1＆#183;h-1 and good stability for 5 h.The high performance can be attributed to the closed-double shell,which had more reactive sites and greater light-harvesting ability,self-supported thin shells with short charge-transfer paths,and a favorable staggered band alignment between the TiO2 and Fe2TiOs.

Ten-eleven translocation-2 affects the fate of cells and has therapeutic potential in digestive tumors

Ten-eleven translocation(TET)methylcytosine dioxygenases catalyze the oxidative reactions of 5-methylcytosine(5-mC)to 5-hydroxymethylcytosine(5-hmC),5-formylcytosine(5-fC),and 5-carboxylcytosine(5-caC),which are intermediate steps during DNA demethylation.It is reported that somatic mutations of TET2 gene are identified in a variety of human tumors,especially in hematological malignancies.The tendency and mechanism of cellular differentiation in different systems are affected by TET2 via regulation of associated gene expression or maintenance of demethylated state.TET2 acts as a critical driver of tumorigenesis through the conversion of 5-mC to 5-hmC and successive oxidation products.Sometimes,it requires special interactions and cofactors.Here,we reviewed recent advances in understanding the function of TET2 proteins in regulating cell differentiation,and its role in various tumors focusing on several digestive cancers.

A Bifurcated Vascular Channel Construction Method based on Diploic Vein Characteristics

In skull bone tissue engineering,cells do not easily survive and proliferate in the scaffold because of the lack of nutrient transport channels.To address these problems,a vascular design and fabrication method based on human skull diploic vein characteristics was proposed.The skull sample was scanned by micro-CT,and the 3D model was constructed by Avizo.By analyzing the characteristics of the diploic vein,the vascular centerline model,path model,taper model and bifurcation model were proposed.Two vascular network examples were constructed by iteration of the bifurcation unit.The mold method of constructing vascular scaffolds embedded within the bionic channels was proposed.The scaffold material is PDMS,and the surface was coated with collagen.The Human Umbilical Vein Endothelial Cells(HUVECs)were planted into the lumen of the channels for 7 days in vitro and found to be able to proliferate.The cells cultured for three days were fluorescently stained,and it was found that the cells were well attached to the surfaces of the lumen.This vascular design and fabrication process can lay a foundation for vascularization in bone tissue engineering.

Task-oriented Hierarchical Control of Modular Soft Robots with External Vision Guidance

General,high-precision theoretical modeling method is not well developed in the field of soft robotics,which holds back motion control and practical application of soft robots.The concept of modularization brings novel structure,novel locomotion patterns as well as novel control method for soft robots.This paper presents the concept of hierarchical control method for modular soft robot system and a H-configuration pneumatic modular soft robot is designed as the control object.The H-configuration modular soft robot is composed of two basic motion units that take worm-like locomotion principle.The locomotion principle of the basic motion unit is analyzed and the actuation sequence is optimized by evolution strategy in VOXCAD simulation software.The differential drive method is applied to the H-configuration modular soft robot with multi motion modes and vision sensor is used to control the motion mode of the robot.The H-configuration modular soft robot and the basic motion unit are assembled by a cubic soft module made of silicone rubber.Also,connection mechanism is designed to ensure that the soft modules can be assembled in any direction and posture.Experiments are conducted to verify the effect of the hierarchical control method of the modular soft robots.