Biomedical subjects

Kai Qiu

Publications and source records attributed to Kai Qiu.

8 recordsLinked to original sources

PubMed2006

Use of recombinant calpain-2 siRNA adenovirus to assess calpain-2 modulation of lung endothelial cell migration and proliferation.

In this study, we developed an adenoviral vector harboring calpain-2 siRNA expression unit in which sense and anti-sense strands composing the siRNA duplex were connected by a loop and transcribed into a siRNA in porcine pulmonary artery endothelial cells (PAEC). We screened one efficient adenoviral vector Ad/si-m187 and found that Ad/si-m187 successfully exerted a gene knockdown effect on calpain-2 mRNA transcription and protein expression levels. The protein content of calpain-2 was reduced by 30%-80% in PAEC infected with Ad/si-m187 in comparison to a control adenoviral vector Ad/si-luc. The mRNA levels of calpain-2 were measured by real-time PCR and were decreased by 60%-100% and in a dose dependent manner. In correspondence to silencing calpain-2 gene expression, calpain-2 activity was decreased significantly. We further evaluated the role of calpain-2 in endothelial cell migration and proliferation. PAEC infected with Ad/si-m187 displayed impaired migration and cell proliferation in comparison to cells infected with control adenoviral vector (Ad/si-luc). These results indicate that adenoviral vector harboring calpain-2 siRNA expression unit is a valuable tool to study the biology of calpains and that calpain-2 plays an important role in lung endothelial cell migration and proliferation.

Adenoviridae↗

PubMed2006

[Structure and performance of calcium polyphosphate for bone tissue engineering].

Porous calcium polyphosphate (CPP) has shown promise of tissue engineered implant application because of the biocompatibility and biodegradation. CPP with different polymerization degree were prepared by controlling the calcining time, and its polymerization degree could be calculated by developed method in this paper. Different crystal types CPP were prepared by quenching from the melt and crystallization of amorphous CPP. From the in vitro degradation, carried out in Tris-HCl buffer, the degradation velocity of CPP was controllable. The weight loss of CPP with different polymerization degrees and crystal types were different. With the increasing of polymerization degree, the weight loss during the degradation was decreasing, contrarily the strength of CPP was increasing. The amorphous CPP could degrade completely in 17 days while gamma-CPP do completely in 25 days. The degradation velocity beta-CPP and alpha-CPP was slower than gamma-CPP and the weight loss was about 12% and 5% respectively. The results of this study indicate that CPP have potential applications for bone tissue engineering as inorganic polymeric biomaterials.

Absorbable Implants↗

PubMed2005

Effect of strontium ions on the growth of ROS17/2.8 cells on porous calcium polyphosphate scaffolds.

Preparation, characterization and cellular biocompatibility study of a series of calcium polyphosphate containing 0-100 mol% of Ca2+ replaced by Sr2+ were reported. The osteoblastic ROS17/2.8 cell line was used and seeded on the strontium-doped calcium polyphosphate (SCPP) scaffolds to estimate its optimal dose and to study its potential to support the growth of osteoblastic cells for bone tissue engineering. The effects of SCPP on cells' proliferation and differentiation were evaluated by MTT and ALP activity assay. The results showed that porous SCPP did not exert cytotoxic effect on the cells. In addition, the proliferation and differentiation of the growth of ROS17/2.8 cells on the SCPP containing a low dose of strontium showed a higher level compared to the control, and the SCPP containing 1% strontium was optimal according to the results of MTT and ALP activity assay. The cells on the porous SCPP formed a continuous layer on the outer and inner surface observed by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The bunchy collagens were excreted from the cells and the calcium granules wrapped by collagens were sedimentated on the surface of cells. The results suggested that the biodegradable SCPP could stimulate the proliferation and differentiation of ROS17/2.8 cells in vitro after addition of proper dose of strontium. The porous SCPP may be a promising material for the bone tissue engineering.

Alkaline Phosphatase↗

PubMed2005

[Advances in research on calcium polyphosphate bioceramic for bone tissue engineering scaffold].

Bone tissue engineering is a novel, developing and challenging science which provides a new way to repair bone lost from injury and disease. Porous calcium polyphosphate bioceramic is one kind of absorptable bioceramic. Owing to its fine biocompatibility and degradability, more and more pieces of research wark have been carried out in bone tissue engineering, and because of its special characteristics, calcium polyphosphate bioceramic is regarded as a promising material for solving the problem of how to match the degradation velocity of scaffold with the velocity of cell growth. The recent research of using calcium polyphosphate bioceramic as the scaffold in bone tissue engineering is summarized, including the property, synthesis and advances.

Bone Substitutes↗

PubMed2004

[The advance in researches for biomedical intelligent polymer materials].

The properties of biomedical intelligent polymer materials can be changed obviously when there is a little physical or chemical change in external condition. They are in the forms of solids, solutions and polymers on the surface of carrier, including aqueous solution of hydrophilic polymers, cross-linking hydrophilic polymers (i.e. hydrogels) and the polymers on the surface of carrier. In this paper are reviewed the progress in researches and the application of biomedical intelligent polymer materials.

Biocompatible Materials↗

PubMed2003

[Research in synthesis of bioactive peptide RGD and the method for its grafting on PET surface].

The aim of this experiment is to graft synthesizing Arg-Gly-Asp peptides (RGD) on the surface of polymer materials, combine endothelial cells with its special site, enhance the adhesion of endothelial cells on the surface, promote the blood compatibility of the biomaterials. Carboxy group (-COOH) was grafted on the materials surface by ultraviolet (UV) radiation, and the RGD serial obtained by liquid phase synthesis was successfully grafted on the disposed materials by chemical reaction. The endothelialization experiment was made also. The grafting results were measured by X-ray photoelectron spectroscopy (XPS), and endothelialization was observed using optical microscope and scanning electron microscope (SEM). The results indicated that the method improves the effect of materials endothelialization. The experiment has made successful use of UV grafting and chemical coupling methods to graft bioactive RGD onto PET film surface. This is a new method of grafting bioactive peptide.

Biocompatible Materials↗

PubMed2003

[The advance of bioactive peptide RGD in the research of bone regeneration].

Clinically, there has been so far no effective way to repair the bone-missing of large extent due to gash, infection and removal of tumor. The solution of this problem can be assisted by the addition of bioactive substances to substrate materials, because the growth of peripheral tissue and the fiber tissue growing the materials can be induced to the direction of bone-tissue by these biomaterials with bioactive peptides. The peptide Arg-Gly-Asp is the point between the integrin which comes from membrane and the ligand. In certain cases, the artificially synthesized RGD can be competitively combined with the integrin on cell surface, and outer-cell information is transmitted into cells, which will cause a series of physiological changes in cells. Presently, it is reported that the RGD has the ability to induce the growth of osteoblasts, restrain the adhesion between osteoclasts and substrates. This paper reviews and introduces the progress made with the work of RGD-inducing bone regeneration.

Biocompatible Materials↗

PubMed1998

99mTc-labeled HAb18 McAb Fab fragment for radioimmunoimaging in nude mice bearing human hepatocellular carcinoma.

AIM:To establish a method of labeling anti-hepatoma McAb (HAb18) Fab fragment modifier with (99m)Tc.METHODS:HAb18 Fab was modified with 2-iminotholane and labeled with (99m)Tc by transchelation from (99m)Tc GH.Labeling yield, radiochemical purity and immunoreactivity were determined by thin layer chromatography (TLC-SG), paper chromatography (PC), gel chromatography (GC) and cell binding assay, respectively. The nude mice bearing human hepatoma were used for radioimmunoimaging (RII).RESULTS:A radiolabeling yield of 50%-80% was obtained, and immunoreactivity (IR) was 30%-40%. Radioimaging results showed that (99m)Tc-HAb18 McAb Fab fragment was concentrated in the tumor 4-8 hours after injection,and the maximum concentration was seen in 12-24 hours,and the T/NT value was 5.18 and 7.48 at 6h and 8h after the injection.CONCLUSION: (99m)Tc-HAb18 McAb Fab fragment could be specifically localized in the tumor of nude mice bearing human hepatocellular carcinoma within 24 hours and this method might be effectively used for labeling McAb Fab fragment with (99m)Tc.

Journal Article↗