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Intracranial aneurysms are mainly caused by the local arterial wal defects and the increased intraluminal pressure. Usualy, the unruptured smal aneurysms are asymptomatic, and the ruptured aneurysms can cause subarachnoid hemorrhage. So far, the etiology and pathogenesis of intracranial aneurysms are not fuly understood. A lot of evidence has showed that intracranial aneurysms are a complex disease of environmental factors and multi-gene interaction. This article reviews the correlation between polymorphisms of elastin and colagen type Ⅰ α2 genes and intracranial aneurysm.
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BACKGROUND:Rat tail colagen type I can promote the increase of muscle fiber cels and migration and tube formation of endothelial cels, which is speculated to provide a more suitable internal environment for the growth of cels. OBJECTIVE:To observe the effect and safety of platelet-derived growth factor-BB (PDGF-BB) with rat rail colagen against apoptosis of human umbilical vein endothelial celsin vitro. METHODS:The passage 4 human umbilical vein endothelial cels were cultured in the medium of rat rail colagen and the reduction ratio in different time points was detected by Alamar Blue. The passage 4 human umbilical vein endothelial cels were divided into four groups and cultured in 24-wel culture plates: control group, PDGF-BB group, H2O2 group, PDGF-BB+colagen group. H2O2 was used to induce cel apoptosis in al the groups. Western blot was used to detect the expression of PDGF-BB, apoptosis-related protein and anti-apoptosis protein after 72 hours. Meanwhile, TUNEL method was used to detect cel apoptotic rate. RESULTS AND CONCLUSION:The tube formation in the human umbilical vein endothelial cels was more than that cultured in normal medium (P < 0.05). Cels cultured with rat tail colagen showed similar growth to normal control cels, indicating rat tail colagen had no cytotoxicity. The expressions of PDGF-BB, Bcl-2, and p-Akt in the PDGF-BB+colagen group were significantly higher than those in the other three groups (P < 0.05), but the expression of Bax was lower than that in the other three groups (P < 0.05). The apoptotic rate in the PDGF-BB+colagen group was lower than the PDGF-BB group and H2O2 group (P < 0.05). These findings indicate that rat tail colagen has no cytotoxicity to human umbilical vein endothelial cells, and rat tail collagen combined with PDGF-BB can predominantly enhance anti-apoptosis effects.
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BACKGROUND:It is an important issue of alveolar ridge preservation after tooth extraction. Because of the limited treatment and geographical conditions, lack of awareness of oral health, many local people in frontier areas in Xinjiang have poor alveolar ridge that is not of timely repair after tooth extraction. Thus, it is important to find a suitable local and efficient way to save the residual ridge, which has a more practical clinical value. OBJECTIVE:To investigate the feasibility of nano-colagen artificial bone used for alveolar ridge preservation in the Kazakh in Xinjiang Tacheng Region, China. METHODS: Sixty-eight Kazakh patients with bilateral extraction from Tacheng region, Xingjiang Uygur Autonomous Region, China were selected in a self-controled trial. According to the principle of a minimum alocation imbalance index, the experimental side and control side of extraction patients were confirmed. In the experimental side, nano-colagen artificial bone was implanted; while, conventional treatment was done in the control side. Multi-slice spiral CT was used to scan the regions of extraction interest to measure the relative gray value of alveolar bone mineral density immediately and 3 months after implantation. RESULTS AND CONCLUSION:Immediately after implantation, tooth extraction sockets were visible on CT images both in the experimental and control sides; but after 3 months, the extraction sockets became unclear on the CT images, and CT values were close to those of the surrounding alveolar process, but bone tissues were ful of the bone graft area in the experimental side. The alveolar bone mineral density was higher in the experimental side than the control side at 3 months after implantation. These findings indicate that the nano-colagen artificial bone has good clinical achievement in alveolar ridge preservation in the Kazakh in Xinjiang Tacheng Region.
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BACKGROUND:Cirrhosis is a long-term consequence of chronic hepatic injury, which has no effective therapy. Mesenchymal stem cels have been shown to play a potential role in the treatment of liver fibrosis/cirrhosis. OBJECTIVE:To investigate the therapeutic effect and mechanism of human umbilical cord-derived mesenchymal stem cels on CCl4 induced liver fibrosis/cirrhosis in rats. METHODS:A CCl4-induced liver fibrotic/cirrhotic rat model was used, and human umbilical cord-derived mesenchymal stem cels were injectedvia the tail vein after modeling. Liver biochemical profile was measured by Beckman Coulter analyzer. Histopathological changes were assessed by Sirius red staining. The expressions of colagen type I, colagen type III, matrix metaloproteinases-2 and tissue inhibitor of matrix metaloproteinases-2 protein and mRNA in liver tissues were observed by immunohistochemistry, western blot and real-time PCR, respectively. RESULTS AND CONCLUSION:Liver biochemical profile indicated the transplantation of human umbilical cord-derived mesenchymal stem cels could improve the liver function of rats with liver fibrosis and cirrhosis. After cel transplantation, except 1-week cel transplantation group, the expressions of the matrix metaloproteinases-2 mRNA and protein were significantly increased, while the expressions of colagen type I, colagen type III and tissue inhibitor of matrix metaloproteinases-2 mRNA and protein significantly decreased, compared with the corresponding model groups. Human umbilical cord-derived mesenchymal stem cels play a role in the treatment of liver fibrosis and cirrhosis through upregulating the expression of matrix metaloproteinases-2 and lowering the expression of inhibitor of matrix metaloproteinases-2. With the continued presence of pathogenic factors, human umbilical cord-derived mesenchymal stem cel transplantation cannot reverse liver fibrosis or cirrhosis, and only delay the process of liver fibrosis or cirrhosis.
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BACKGROUND:Craniotomy for severe traumatic brain injury is required to maintain the integrity of the dura mater. The artificial dura mater is now a common dural repair material, and looking for the ideal artificial dura mater is the exploring direction of neurosurgery. OBJECTIVE:To explore the application of colagen sponge artificial dura in severe traumatic brain injury METHODS:A retrospective analysis of 96 patients with severe head injury was performed, including 32 cases of the artificial dura with tightly suturing as the control group, and 64 cases of the artificial dura of colagen sponge without suturing as the experimental group. Operating time for hematoma clearance, blood loss, postoperative mechanical ventilation time, ICU monitoring time, the total number of hospitalized days as wel as time interval from hematoma clearance to cranioplasty, operative time for cranioplasty, blood loss, and Glasgow Coma Scale scores after dural damage and 6 months postoperatively in the two groups were measured. RESULTS AND CONCLUSION:The same purpose was achieved in the two groups. The amount of bleeding during hematoma clearance, postoperative mechanical ventilation time, monitoring time in ICU, the total number of hospitalized days and Glasgow Coma Scale score of 6 months postoperatively showed no significant difference between the two groups (P> 0.05). But operative time for hematoma clearance and cranioplasty as wel as blood loss in the second operation were statisticaly significant between two groups (P< 0.05). The colagen sponge artificial dura in severe traumatic brain injury can fuly play a good role in reducing intracranial pressure, keeping brain functions, shortening operative time, and improving outcomes of patients, which has similar effects to tightly suturing the dura and creates favorable conditions for the folowing cranioplasty.
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BACKGROUND:Insulin-like growth factor-1 can promote mitosis of fibroblasts as wel as periodontal cellgrowth, differentiation and synthesis of extracelular matrix. OBJECTIVE: To observe the effects of chitosan/colagen composite scaffold carrying insulin-like growth factor-1 on proliferation of human periodontal ligament cels. METHODS: The human periodontal ligament cels were seeded on chitosan/colagen composite scaffold carrying insulin-like growth factor-1 and ordinary colagen scaffold. The release of recombinant human transforming growth factor-β1 was detected at 1, 24 hours and 1 week after culture; celladhesion and proliferation were detected at days 1, 7 and 28. RESULTS AND CONCLUSION:The release rate of recombinant human transforming growth factor-β1 in the composite scaffold was significantly lower than that in the ordinary colagen scaffold at 1, 24 hours and 1 week after cellseeding (P < 0.01). The celladhesion and proliferation showed no difference between two groups at day 1 after cellseeding, but became significantly higher in the composite scaffold than that in the ordinary colagen scaffold at days 7 and 28 (P < 0.01). These findings indicate that chitosan/colagen composite scaffold carrying insulin-like growth factor-1 can significantly promote the proliferation of the human periodontal ligament cels.
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BACKGROUND:Matrix metaloproteinase-1 can degrade extracelular matrix, which is mainly colagen type I, and has the potential to reverse fibrosis tissue. OBJECTIVE:To construct the recombinant adenovirus vector containing human matrix metaloproteinase-1 (hMMP-1) gene with GatewayTM Clone Technology, and observe the capacity of degrading colagen type IIIin vitro. METHODS: The gene hMMP-1 was amplified by using PCR from the pcDNA3.1 plasmid and was cut down by the double endonuclease. The linear gene fragment was connected to the entry vector pENTERTM 1A. Then the entry clone and the destination vectors pJTI? R4 Dest CMV-N-EmGFP pA Vector recombined using the LR reaction to form the expression clone pAd-hMMP-1-eGFP. The linear pAd-hMMP-1-eGFP cut down by endonucleasePac I was transfected into HEK293A cels to packaging the Ad-hMMP-1-eGFP. The transfected situation was observed under a fluorescence microscope, the target protein expression was detected by western-blot assay and RT-PCR. Cels can be divided into three groups: blank control group: HEK293A cels, AD-EGFP group: HEK293A cels were infected by Ad-eGFP, AD-HMMP1-EGF group: HEK293A cels were infected by Ad-hMMP1-eGFP and colagen type III. The content of colagen type III was detected by ELISA kits after 24, 48 and 72 hours. RESULTS AND CONCLUSION: It was confirmed that the entry vector and the destination vector both contained hMMP-1 target gene by restriction analysis and sequencing. The green fluorescent protein was observed in the 293A cels transfected by the Ad-hMMP-1-eGFP at 4 days. The fluorescence intensity was the highest at 10 days. The virus was colected at 12 days, the viral titer was determined as 4.84 × 1010 PFU/mL, the target protein was efficient expressionvia western-blot assay. Blank control group and AD-EGFP group had no obvious change of colagen content with the extension of time. The rate of colagen degradation in AD-HMMP1-EGFP group was 24%, 56% and 81% respectively at 24, 48, 72 hours. AD-HMMP1-EGFP group degraded colagen significantly compared with the other two groups (P < 0.01). The recombinant adenovirus vector containing hMMP-1 was successfuly constructed by using the Gateway technology, this method was more efficient and specific than with the traditional methods. The hMMP1 degraded colagen type III significantlyin vitro.
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BACKGROUND:Articular chondrocytes with the ability of autocrine and paracrine can provide the growth factors and microenvironment for synovial mesenchymal stem cels differentiating into the chondrocyte. The three-dimensional scaffold could provide space for cels adhesion, proliferation and differentiation. OBJECTIVE: To study the ability of chondrogenesis by co-culturing synovial mesenchymal stem cels and chondrocytes under the three-dimensional condition. METHODS:The synovial membrane and articular cartilage were harvested from rat knee joint. The synovial mesenchymal stem cels and chondrocytes were obtained through the method of enzyme digestion. The passage 3 synovial mesenchymal stem cels and passage 2 chondrocytes were co-cultured in the chitosan/I colagen composite scaffolds at the ratio of 1:2. Then, the cels/scaffold composite was harvested to be examined morphologicaly, histologicaly and immunohistochemicaly after being cultured 21 days. The confocal laser was also employed to detect the cels distribution in the scaffold. RESULTS AND CONCLUSION: After being cultured 72 hours, it could be observed from the cels/scaffold composite examined through the scanning electron microscope that the cels adhered on the surface of the scaffold and extracelular matrix surrounding the cels was seen on the scaffold. After being cultured 21 days, it could be found through the confocal laser scanning that the cels were wel-distributed on the scaffold, and cels decreased gradualy. Type II colagen was positive in the extracelular matrix immunohistochamicaly. It suggested from this study that the synovial mesenchymal stem cels could be co-cultured with chondrocytes in the chitosan/I colagen composite scaffolds and have the ability of chondrogenesis differentiation.
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BACKGROUND:Colagen sponges are applied for hemostatic use, wound healing, and residual cavity filing, which have great values in clinical application and scientific research. OBJECTIVE:To investigate the biological properties, biocompatibility and biodegradability of colagen spongesin vivo. METHODS: The spatial structure, pore diameter and porosity of colagen sponges were characterized by scanning electron microscopy. Transmission electron microscopy was used to observe the conformation of colagen sponges. The secondary structure and thermal denaturation temperature of colagen sponges were analyzed by circular dichroism spectrum. Colagen sponges were implanted intramuscularly into the spinal cord of New Zealand rabbits to observe the degradation and absorption and histological changesin vivo. RESULTS AND CONCLUSION: Colagen sponges had porous structure with varying pore sizes ranging 40-150 μm, the mean pore size of 100 μm, the thickness wal of 1 μm, and a porosity of approximately 95.8%. Colagen sponges had a typical porous structure and periodic light and dark zones. The solution of colagen sponges had a weak positive band near 220 nm and an intense negative band near 206 nm, which indicated a classic triple helix. And the secondary structure and thermal stability of colagen sponges were similar to that of liquid colagen. Colagen sponges began to degrade at 4 weeks, and remained 20% at 12 weeks. These sponges had been associated with foreign body response and inflammation within 2 weeks after implantation. With wound healing, inflammatory reactions gradualy reduced and disappeared. During the implantation and degradation of sponges, no significant fibrous capsule formed and no tissue necrosis occurred at implantation site, indicating that colagen sponges have good performance in bioactivity, biocompatibility and degradation.
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BACKGROUND:Low toxicity of Genipin has certain species and cellspecificity. Biocompatibility of Genipin cross-linked type I colagen with human adipose-derived stem cels is essential for construction of tissue-engineered adipose. OBJECTIVE:To investigate the bbiocompatibility of Genipin cross-linked type I colagen with human adipose-derived stem cels. METHODS:Human adipose-derived stem cels were isolated and cultured to the third generation, and the cels were seeded on Genipin cross-linked type I colagen scaffold. MTT assay was used to evaluate the adhesion and proliferation of cels on the scaffold, and the toxic effects of Genipin cross-linked type I colagen on human adipose-derived stem cels. Optical microscopy and scanning electron microscopy were utilized to observe the adhesion and growth process of human adipose-derived stem cels on the scaffold as wel as the morphological changes of cels. RESULTS AND CONCLUSION:Human adipose-derived stem cels could adhere to the scaffold immediately after seeded and increase gradualy on the scaffold, with the average adhesion rate of 86.5%. Optical microscopy and scanning electron microscopy showed that human adipose-derived stem cels adhered wel on the scaffold. The cels increased gradualy over time, and could migrate into the scaffold, and distribute evenly with the passage of time when observed with optical microscopy. The result showed Genipin possesses very low cytotoxicity to the cels, and the outstanding biocompatibility is found between the cels and scaffoldin vitro after cross-linked with Genipin.
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BACKGROUND:Titanium and titanium aloy are used mostly in artificial joints, fracture fixation, and oral transplantation, while there are complex cases of insufficient bone mass in these areas. The deepened research of stem cels offers a solution for bone injury to promote new bone formation. The biocompatibility of titanium and stem cels and optimization of titanium surface modification have aroused people's attention. OBJECTIVE:To investigate whether the biocompatibility of titanium and human adipose-derived mesenchymal stem cels can be improved by type I colagen modification of titanium sheets. METHODS:The experiment was divided into two groups. Modification group: titanium sheet was modified with type I colagen; control group: titanium sheet was not modified with type I colagen. Human adipose-derived mesenchymal stem cels at passage 6 were implanted into titanium sheet in two groups. Then we calculated the number of adherent cels in two groups at 1, 2 and 4 hours after implantation, and compared the celladhesion rate. MTT assay was used to observe the proliferation of cels on titanium sheet at 2, 4, 6 and 8 days after implantation. DNA and protein content of cels were detected at 3, 6, 9 days after implantation. The growth of human adipose-derived mesenchymal stem cels seeded upon the titanium sheets was observed under scanning electron microscope at 6 days. RESULTS AND CONCLUSION:When the cels were cultured for 1 hour and 2 hours, the number of adherent cels in the modification group was higher than in the control group (P < 0.05). The absorbance of cels in two groups was increased as the culture time, as detected by MTT assay. The modification group had a significantly higher absorbance value than the control group at 4, 6, 8 days (P < 0.05). DNA and protein contents of the cels in the modification group were higher than that in control group at 6 and 9 days (P < 0.05). At 6 days, the number of adherent cels and secretion of adherent stromal cellmatrix in the modification group were significantly better than that in control group, observed by scanning electron microscopy. Type I colagen modified titanium sheets have good surface activity and biocompatibility, and can promote the proliferation of human adipose-derived mesenchymal stem cels.
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La durabilidad de las restauraciones adhesivas representa un punto crítico en el campo de la restauración dentaria, ya que la biodegradación es un factor decisivo para el fracaso de dichas restauraciones, a lo largo del tiempo. Este artículo busca esclarecer los mecanismos envueltos en el deterioro de la línea de unión, así como apuntar nuevos caminos o desafíos para la obtención de restauraciones adhesivas cada vez más durables.
The durability of adhesive procedures represents a critical point in function of the biodegradation to represent a decisive factor for the failure of the restorations. This aim of this study was to carry through a revision of literature with the purpose to clarify the involved mechanisms in the degradation of the bonding interface, as well as pointing new ways or challenges with respect to the attainment of more durable adhesive restorations.