Objective To analyze effect of stem cell transplantation on the expression of smooth muscle actin (SMA), basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) in the myocardium of dogs with ischemic mitral regurgitation.Methods 24 healthy male experiment dogs were selected, 6 were collected randondy as normal group, the others were used to construct mitral regurgitation model.After that, the modelized dogs were divided into three groups, 5 dogs in model group, 6 dogs in experiment group and 6 in control group.The experimental group were given 2 mL stem cells suspension to ischemic myocardial, control group was infused without stem cells in DMEM medium, and then the SMA, bFGF and VEGF expression levels of myocardial tissues in each groups were detected and analyzed.ResuIts Compared with control group and model group, the heart function of experiment group were improved more obviously, such as cardiac output (CO) and stroke volume (SV) increased significantly (P<0.05).Myocardialα-SMA were significantly lower (P<0.05).bFGF contents in myocardial tissue increased significantly (P<0.05).The content of VEGF in myocardial tissue significantly increased (P<0.05).ConcIusions Stem cell transplantation can inhibit the expression of SMA in myocardium of ischemic mitral regurgitation, and promote the expression of bFGF and VEGF, has a better effect on heart function.

OBJECTIVETo elucidate the significance of detecting cytokeratin gene (CK-20 mRNA) expression in metastatic lymph nodes of colon carcinoma patients.

METHODSThe expression of CK-20 mRNA was detected in 342 lymph nodes by reverse transcription-polymerase chain reaction (RT-PCR) in 49 colon carcinoma patients. Its incidence was compared with that by routine pathologic examination.

RESULTSThe positive rates of detecting metastasis in the lymph nodes were 21.9% by RT-PCR and 11.1% by routine pathologic examination.

CONCLUSIONThe detection of cancer metastasis in the lymph nodes in colon carcinoma is almost doubled (21.9% vs 11.1%) by CK-20 mRNA, which may provide a guiding significance in staging, treatment planning and prognosis in the prognostic estimation of colon carcinoma patients.

Adult ; Aged ; Colonic Neoplasms ; diagnosis ; genetics ; pathology ; Female ; Gene Expression ; Genetic Markers ; genetics ; Humans ; Intermediate Filament Proteins ; genetics ; Keratin-20 ; Lymphatic Metastasis ; diagnosis ; Male ; Middle Aged ; Neoplasm Staging ; Prognosis ; RNA, Messenger ; biosynthesis ; Reverse Transcriptase Polymerase Chain Reaction

To detect the properties of natural xenogeneic bone derived materials which were processed with different physical and chemical treatments, we made fully deproteinized bone(FDB), partially deproteinized bone (PDPB), partially decalcified bone(PDCB) from pig ribs. Their morphological features, constitute components and mechanical properties were examined by scanning electron microscopy, x-rays diffraction analysis, mechanical assay and so on. The results showed that FDB, PDPB and PDCB maintained natural network pore system. The ratios of calcium to phosphorus were 1.81, 1.74 and 1.50, and the protein contents were 0.01% +/- 0.02%, 22.41% +/- 0.83% and 35.75% +/- 2.12% respectively. The sequence of their mechanic strength was PDCB > PDPB > FDB. These data indicate that FDB, PDPB and PDCB possess natural network pore system. Their organic and inorganic component ratios and contents are different, so their mechanic properties are not alike. Additionally, more investigations will be necessary to detect the biocompatibility of the three different scaffold materials of natural derived bone.
Animals ; Biocompatible Materials ; chemistry ; Biomechanical Phenomena ; Bone and Bones ; chemistry ; Materials Testing ; Swine ; Tissue Engineering

This article introduces a three-dimensional scaffold which is used to perform three-dimensional cell culture under mechanical stretch from the point of construction of tissue-engineered tissue. The composition, structure, surface characteristics, mechanical property, and cell compatibility of the scaffold have been studied by using surface chemistry and material mechanics testing methods. The results indicate that the polyvinyl alcohol (PVA) sponge, which is water-tolerant, coated with Poly-DL-lactic-co-glycolic acid (PLGA) possesses a good nature in appropriate surface feature, porosity, elastic recoil, and cell compatibility. These features provide wide options for using this scaffold to study the effects of mechanical stretch on cells maintained in three-dimensional culture to provide a three-dimensional matrix.
Biocompatible Materials ; Biomechanical Phenomena ; Cell Culture Techniques ; Humans ; Lactic Acid ; Polyglycolic Acid ; Polymers ; Polyvinyl Alcohol ; Surface Properties ; Tendons ; cytology ; Tissue Engineering

Titanium alloy material (TC4) samples were treated with nitriding technique. The dynamic friction and wear behavior of the modified layer were examined on a reciprocating sliding rig in artificial saliva. Microhardness, depth profile and wear mechanisms were investigated by means of MVK-H12, TALYSURF6, XPS and microscopy. The results demonstrate that after being treated with nitriding technique the titanium alloy material (TC4) has better tribological behavior and up-graded wear resistance. The wear mechanism involves adhesion.
Adsorption ; Biocompatible Materials ; Dental Alloys ; chemistry ; Dental Materials ; Dental Prosthesis ; Electricity ; Friction ; Humans ; Materials Testing ; Surface Properties ; Titanium ; chemistry

OBJECTIVETo detect occult metastases in lymph nodes from patients with colorectal carcinoma and its clinical significance.

METHODSThe metastases in 260 lymph nodes from 39 histologically verified colorectal cancer patients were studied by both hematoxylin-eosin (HE) staining and cytokeratin-20 (CK20) specific RT-PCR. Ten normal lymph nodes were served as negative controls, and HT29 colon cancer cell line and 5 colorectal cancer specimens as positive controls.

RESULTSTen normal lymph nodes were CK20-negative, HT29 cells and 5 tumor specimens were all CK20-positive. All 29 lymph nodes from 16 patients which confirmed metastases by HE staining exhibited CK20 positive expression; an additional 28 lymph nodes from 5 patients with no histologically detectable metastases expressed CK20 mRNA, i.e. presence of metastases. The difference of the positivity was significant (11.1% vs 21.9%, P < 0.01). According to the HE staining, the cases of Dukes' A, B, C and D were 3, 20, 12 and 4, respectively. In the 20 patients of Dukes' B stage, 5 of them had CK20-positive lymph nodes.

CONCLUSIONCK20-specific RT-PCR is a highly sensitive, specific and simple method for detecting occult metastases in lymph nodes. The detection of CK20 mRNA expression in lymph nodes is recommended to precisely determine tumor stage and postoperative adjuvant therapy for patients with colorectal cancer, and further studies should be done in future to confirm the findings.

Adult ; Aged ; Colorectal Neoplasms ; genetics ; pathology ; Female ; Gene Expression Regulation, Neoplastic ; HT29 Cells ; Humans ; Intermediate Filament Proteins ; genetics ; Keratin-20 ; Lymph Node Excision ; Lymph Nodes ; metabolism ; pathology ; Lymphatic Metastasis ; genetics ; pathology ; Male ; Middle Aged ; RNA, Messenger ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

In this study we examined the in vitro characteristics of tenocyte adhesion to biologically-modified surface of polymer. Polylactic-co-glycolic acid (PLGA) 85/15 films were prepared by a solvent-casting technique. Each film was adhered onto the bottom of a chamber. The film was precoated with poly-D-lysine (PDL), and then coated with serum-free F12 medium containing various concentrations of fibronectin (FN), type I collagen (CN I), and insulin-like growth factor1 (IGF-1). The monoclonal antibodies (to FN and to CN I) with various dilutions were used to inhibit attachment of tenocytes to surface precoated with FN or CN I. Human embryonic tendon cells (HETCs) and transformed human embryonic tendon cells (THETCs) were used as the seeding cells. The system used for the measurement of adhesion force was the micropipette aspiration experiment system. The micropipette was manipulated to aspirate a small portion of the tenocyte body by using a small aspiration pressure. Then the pipette was pulled away from the adhesion area by micromanipulation. The minimum force required to detach the tenocyte from the substrate was defined as the adhesion force. The results showed that modification of FN or CN I by precoating significantly enhanced attachment of tenocytes to surface of polymer (P < 0.05). As antibodies to FN or CN I were added to a polymer film precoated with FN or CN I, the adhesion force decreased significantly (P < 0.05). We concluded that the specific adhesion forces of tenocytes to extracellular matrix adhesion proteins (FN and CN I) had coordinated action and showed good dependence on their precoating concentrations, and were inhibited by the antibodies to these adhesion proteins. Films precoated with IGF-1 strongly accelerated the adhesion of tenocytes to polymer. These results indicate that the specific adhesion of tenocytes to polymer can be promoted by coating extracellular matrix adhesive proteins and insulin-like growth factor1. It is of great importance to construct tissue-engineered tendon.
Biocompatible Materials ; chemistry ; Cell Adhesion ; drug effects ; physiology ; Cells, Cultured ; Extracellular Matrix Proteins ; pharmacology ; Growth Substances ; pharmacology ; Humans ; Lactic Acid ; chemistry ; Polyglycolic Acid ; chemistry ; Polylysine ; pharmacology ; Polymers ; chemistry ; Tendons ; cytology ; embryology ; physiology ; Tissue Engineering

This is a study on the histologic pattern and mechanical properties of tissue-engineered tendon implanted for treatment of tendon defects. Tendons were resected from Roman chickens. Tendon cells were isolated from the tendons and cultured in vitro. The 2nd-4th passages of tendon cells were seeded on the degradable polyglycolic acid mesh to form cell-scaffold composites, which were further cultured for 7-10 days to construct tissue-engineered tendons. The tendon defects, 0.5 cm-0.8 cm in length, were made in the second digit flexor tendon bilaterally in 20 Roman chickens and then bridged with the constructed tissue-engineered tendons. At 2 weeks, 4 weeks, 6 weeks, and 8 weeks post-operation, the samples of regenerated tendons were collected for gross examination, histologic staining and biomechanical test. After implantation of the tissue-engineered tendons, the wounds healed well. The gross appearance, the cells and collagen fibers arrangement of the regenerated tendons were similar to those of natural tendons, but there were relatively not many closely packed collagen fiber bundles organized in parallel with the tendons ("remodel"), so the maximum tensile force increased slowly and its value was 15.40+/-10.63 N at 8 weeks after surgery, reaching only 23% of that of natural tendon. The maximum strain was 22.49%+/-10.21% at 8 weeks, being 10% higher than that of natural tendons. Polyglycolic acid scaffolds are degraded in vivo so rapidly that the regenerated tendons lose the normal biomechanical stimulus and then are unable to be remodeled. As a result, the mechanical strength of regenerated tendons is much lower than that of natural tendons. These results suggest that the normal biomechanical stimulus may be an important factor for the regenerated tendons to remodel.
Animals ; Animals, Newborn ; Biomechanical Phenomena ; methods ; Cell Separation ; Cells, Cultured ; Chickens ; Female ; Implants, Experimental ; Tendon Injuries ; surgery ; Tendons ; cytology ; physiology ; surgery ; Tensile Strength ; Tissue Engineering ; methods

OBJECTIVETo study the histocompatibility of three bio-derived bones.

METHODSAfter treatment with different physical and chemical method, three bio-derived bones, the composite fully deproteinized bone (CFDB), partially deproteinized bone (PDPB) and partially decalcified bone (PDCB) were implanted into rabbits. The toxicity, immune response and subperiosteum osteogenesis of CFDB, PDPB and PDCB were studied through gross observation, serum antibody measurement, evaluation of local cellular immune response and HE staining.

RESULTSThe study showed that CFDB, PDPB and PDCB had no toxicity. They could conduct peripheral tissue to grow into them and had no harmful effect on subperiosteum osteogenesis. They could also promote cartilage and osteoid tissue derived from periosteum to calcify to new bone, and combine with the peripheral bone. The degree of immune response caused by them was in the sequence of PDCB > PDPB > CFDB.

CONCLUSIONSThe three bio-derived bones, CFDB, PDPB and PDCB have good histocompatibility.

Animals ; Antibodies ; blood ; Bone Transplantation ; Bone and Bones ; immunology ; Female ; Histocompatibility ; Histocompatibility Testing ; Male ; Rabbits ; Tissue Engineering

Experiments have been performed to investigate why the biomechanical strength of repaired tendons is lower than that of the normal tendon when the engineered tendons are implanted in vivo to replace the tendon defects. We seeded the primary culture tendon cells derived from Roman chickens' digital flexor tendons on the degradable polyglycolic acid meshes to construct tissue-engineered tendons. The flexor tendon defects (0.5 cm-0.8 cm) excised in second digit bilaterally in 20 Roman chickens, had been repaired with the constructed tissue-engineered tendons. The samples of repaired tendons were collected at 2, 4, 6 and 8 weeks after operation. Tests for scaffold weight, hydroxyproline content, and mechanical strength of the samples were performed. We found that from 2 weeks to 8 weeks afteroperation, the weight of the scaffolds decreased significantly, almost disappearing at 8 weeks; the hydroxyproline content determining the total collagen content increased gradually without significance; mechanically, both energy at break and tensile strength showed a tendency of drastic decrease at first 4 weeks afteroperation and a gradual increase afterwards, but the tensile strength at 8 weeks afteroperation was only 23% of that of the normal tendon. We conclude that the lower biomechanical strength of repaired tendons is owing to the serious mismatch between scaffold degradation and collagen synthesis.
Achilles Tendon ; injuries ; Animals ; Biocompatible Materials ; metabolism ; Bioprosthesis ; Cell Culture Techniques ; Chickens ; Collagen ; metabolism ; Female ; Prosthesis Implantation ; Tendon Injuries ; surgery ; Tendons ; cytology ; Tensile Strength ; Tissue Engineering ; methods