OBJECTIVETo investigate the mechanisms underlying the incorporation of microparticles(MP) derived from human bone marrow mesenchymal stem cells (MSCs) into human umbilical cord endothelial cells (HUVECs).

METHODSMPs were isolated from the supernatants of MSCs which had exposed to a hypoxia/serum-deprivation condition. Electron microscope was used to identify the MPs. The surface molecule profile was evaluated with the bead-based flow cytometry technique. The expression level of the phosphatidylserine receptor (PSR) was detected by immunofluorescence cytochemistry. MPs were co-cultured with HUVECs in the presence or absence PSR-antibody, and the internalization of MPs was observed with laser scanning microscopy.

RESULTSThe MPs derived from MSCs expressed highly PS, while PSR expressed on the surface of HUVECs. The confocal result revealed that MPs could quickly be uptaken by the endothelial cells, and mainly distributed in the cytoplasm surrounding of the nuclei. The internalization of MPs reduced significantly after PSR specific blockage.

CONCLUSIONThe reaction between PS on the MP and the PSR of HUVECs plays an important role in the internalization of MSC-MPs.

Cells, Cultured ; Coculture Techniques ; Endothelial Cells ; Flow Cytometry ; Humans ; Mesenchymal Stromal Cells ; Umbilical Cord

OBJECTIVETo construct a human cervical spine with bilateral vertebral artery fluid-solid coupling model.

METHODSHelical CT images under the principle of reverse engineering and meshed in finite element model（FEM） related software were used to establish a human cervical spine with bilateral vertebral artery fluid-solid coupling model. In the process of modeling of vertebral body, vertebral artery, ligament, intervertebral disc, cartilage and endplate large anatomic data and cadaver experiments results were referenced. From the morphology and function the simulation of model with real physiological status was tested.

RESULTSThe study showed that the stress concentration on the surface of vertebral body and the blood wall of the bilateral vertebral artery, and the result of the volume flow rate-time curve of bilateral vertebral artery of the model were consistent with the published literatures. This model was well consistent with the clinical phenomenon.

CONCLUSIONThe three-dimensional FEM of the human cervical spine established by the introduced method has been effectively verified. The modeling method would provide a new tool for research on the cervical spine biomechanics.

Biomechanical Phenomena ; Cadaver ; Cervical Vertebrae ; anatomy & histology ; Finite Element Analysis ; Humans ; Intervertebral Disc ; Models, Anatomic ; Tomography, Spiral Computed ; Vertebral Artery ; anatomy & histology

Objective: To construct a human cervical spine with bilateral vertebral artery fluid-solid coupling model .Methods: Helical CT images under the principle of reverse engineering and meshed in finite element model ( FEM ) related software were used to establish a human cervical spine with bilateral vertebral artery fluid-solid coupling model . In the process of modeling of vertebral body , vertebral artery , ligament , intervertebral disc , cartilage and endplate large anatomic data and cadaver experiments results were referenced .From the morphology and function the simulation of model with real physiological status was tested .Results: The study showed that the stress concentration on the surface of vertebral body and the blood wall of the bilateral vertebral artery , and the result of the volume flow rate-time curve of bilateral vertebral artery of the model were consistent with the published literatures .This model was well consistent with the clinical phenomenon .Conclusion: The three-dimensional FEM of the human cervical spine established by the introduced method has been effectively verified.The modeling method would provide a new tool for research on the cervical spine biomechanics .

BACKGROUNDPressure therapy improves hypertrophic scar healing, but the mechanisms for this process are not well understood. We sought to investigate the differential expression of matrix metalloproteinases (Mmps) and collagen in posttraumatic hypertrophic scar tissue with mechanical pressure and delineate the molecular mechanisms of pressure therapy for hypertrophic scars.

METHODSFibroblast lines of normal skin and scar tissue were established and a mechanical pressure system was devised to simulate pressure therapy. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting assays were used to compare differences in the mRNA and protein expression of Mmps and collagen in scar fibroblasts before and after pressure therapy.

RESULTSThe expression differed between the hypertrophic scar cell line and the normal cell line. RT-PCR assays showed that Collagen I, highly expressed in the hypertrophic scar cell line, decreased significantly after pressure therapy. Mmp2, Mmp9, and Mmp12 expression in the hypertrophic scar tissue increased significantly after pressure therapy (P < 0.05). Western blotting assays further revealed that Mmp9 and Mmp12 expression increased significantly in the hypertrophic scar tissue after pressure therapy (P < 0.05) but not Mmp2 expression (P > 0.05).

CONCLUSIONMechanical pressure induces degradation of Collagen I in hypertrophic scar tissue by affecting the expression of Mmp9 and Mmp12.

Cell Line ; Cicatrix, Hypertrophic ; enzymology ; metabolism ; Collagen Type I ; genetics ; metabolism ; Humans ; Matrix Metalloproteinase 12 ; genetics ; metabolism ; Matrix Metalloproteinase 2 ; genetics ; metabolism ; Matrix Metalloproteinase 9 ; genetics ; metabolism

Objective To investigate the source and genetic background of methicillin-resistant Staphylococcus aureus in the year of 2006,in China. Methods From January to December 2006,a total number of 302 consecutive and non-repetitive methicillin-resistant Staphylococcus aureus were collected from 17 Teaching hospitals in 15 areas. Genotypes of SCCmec were determined by multiplex PCR and multilocus sequence typing (MLST) was used to type the house-keeping genes. The implementation of the spa typing method was straightforward,and the results obtained were reproducible,unambiguous,and easily interpreted. Results All areas but Dalian harbored SCCmec Ⅲ while Dalian harbored SCCmec Ⅱ most. There were two strains in Guangzhou,harboring SCCmec Ⅳ. There were four strains of sequence type(ST),with ST239 accounted for 46.7% and ST5 accounted for 44.4%. ST59 accounted for 6.7% and ST88 accounted for 2.2%. There were fourteen strains of Spa typing,with t30 accounted for 52.6% ; t37 accounted for 27.2% ; t2 accounted for 12.9% ; t632 accounted for 2.3% ; t437 accounted for 1.3% ; t570,t601 accounted for 0.7% ; t377,t459,t796,t899,t1152,t2649 accounted for 0.3% ; no-typing accounted for 0.3%,respectively,pvl gene was not detected. Conclusion The main clone strains were ST239-MRSA-SCCmec Ⅲ-t30,ST5-MRSA-SCCmec Ⅱ-t2,with unique geographic distributions across the whole nation.

OBJECTIVETo understand the characteristics of embB gene mutation of Mycobacterium tuberculosis (MTB) isolates from tuberculosis patients in Chongqing, and the value of embB306 as a molecular marker used to diagnose ethambutol (EMB)-resistant MTB strains.

METHODSDirect sequencing was used to analyze the polymorphism of embB mutation in 51 EMB-resistant MTB strains and 50 EMB-sensitive MTB strains. And diagnostic testing was used to evaluate the value of embB306 as a molecular marker of EMB -resistant MTB strains as compared with the traditional sensitivity test.

RESULTSAll 34 of 51 EMB-resistant strains (66.7%) and 3 of 51 EMB-sensitive strains (6%) had had embB306 mutation. The embB306 mutation rate in EMB-resistant strains coming from previously treated case was 87.5%, showing significantly higher than that from new cases (48.1%, P < 0.01); embB306 mutation rate was increased with the number of the resistant drugs; embB306 mutation serving as a marker to diagnose EMB-resistant MTB strains comparing with the traditional sensitivity test, had the rate of sensitivity = 66.7%, specificity = 94.0%, accuracy = 80.2% and Youden index = 60.7%.

CONCLUSIONembB306 mutation should be the main mechanism of MTB resistance to EMB in Chongqing, showing an association with the history of the treated and numbers of the resistant drugs. embB306 mutation should be a good marker to diagnose EMB-resistant MTB strains.

China ; DNA Mutational Analysis ; DNA, Bacterial ; genetics ; Genes, Bacterial ; Humans ; Mutation ; Mycobacterium tuberculosis ; drug effects ; genetics ; isolation & purification ; Pentosyltransferases ; genetics ; Tuberculosis, Multidrug-Resistant ; microbiology