Biomedical subjects

Xizheng Zhang

Publications and source records attributed to Xizheng Zhang.

5 recordsLinked to original sources

PubMed2006

[A model for studying on mechanical responses of osteoblast seeded in three dimensional scaffold].

OBJECTIVE: To establish a model for studying on mechanical responses of osteoblasts seeded in 3 dimensional(3D) scaffold. METHODS: Fifty pieces of bio-derived cancellous bones, whose holes were 500 to 800 microm and density was 0.36 to 0.45 g/cm3, were obtained as the scaffolds. They were cultured with the third passage suspension of Wistar rat. Twenty-four of the 50 scaffolds were constructed under apparent strain sine waveform with amplitude of 1 000 microepsilon, frequency of 3 Hz, and duration of 3 min/d, as experimental group. The other scaffolds were control group. After 3-day coculture, osteoblasts were observed with scanning electron microscope. The proliferation of the osteoblasts was checked by MTT on scheduled date. RESULTS: Scanning electron microscopic observation showed that osteoblasts attached and spread on the trabeculae, which presented the validity of the model under proper mechanical condition. Experiment showed that mechanical environment promoted the proliferation of osteoblasts. The observation of proliferation of osteoblasts showed that the quantity of osteoblasts in the experimental group was higher than that in the control group 1, 4, 8, 12, 16, 20, 24, and 28 days after culturing. There was significant difference between the two groups 12, 16, 20, 24, and 28 days after culturing (P < 0.05). CONCLUSION: The establishment of the model can facilitate the study of mechanical responses of osteoblasts under different conditions.

Animals↗

PubMed2006

[Influence of stretch strain and pressure on expression of osteoblasts' FOS protein].

Uniaxial stretch strain and compressive pressure of 2 atm were applied to rat's osteoblasts, and then immunohistochemistrical staining was used to detect the expression of osteoblasts' c-fos gene. The experiment result indicated the osteoblasts' FOS proteins increased prominently, and the FOS proteins concentrated in nucleolus after having endured two different kinds of loadings. It is very important to prompt stress and strain in promoting osteoblast proliferation.

Animals↗

PubMed2005

[A new loading bioreactor for bone tissue-engineering applications].

Bone cells live in an environment heavily influenced by mechanical force. The development of bone tissue is dependent on the environment that surrounds it, both in vivo and in vitro. A loading stimulator on research of bone tissue-engineering was developed based on the mechanism of mechanosensation, scaffolding composites with mechanical strains with more physiologic magnitude, frequency components, and waveform. It also achieves the mechanical environment particularly in hard scaffold enough strong like cancellous bone. The device was tested using a reference scaffold made of better elastic plastic material. The experiment results showed that the device could be used in precision strain controls. Since the drive of the stimulator comes from the usage of smart material, piezoceramics, the strain at physiological level is controlled precisely. The stimulator provides a mechanical condition under which the effects of loading applied on bone tissue-engineering culture are conveniently investigated. Furthermore, after the stimulator is improved, it will be an appropriate bioreactor for bone tissue-engineering culture.

Bioreactors↗

PubMed2004

[Effects of recombinant bovine basic fibroblast growth factor on osteoblast's growth and c-fos expression].

Rat's osteoblasts cultured in vitro were stimulated by recombinant bovine basic fibroblast growth factor(rb-bFGF). After 1-2 days, the osteoblast grew long protuberance, the numbers of osteoblasts were greater than the control groups', the vitality of osteoblasts was better than that of control groups. After 1 hour, the expression of c-fos in osteoblast increased when compared with that in the control group. After the osteoblasts having been stimulated for 1-2 days, the expression of c-fos increased more conspicuously. These results show that bFGF can boost the osteoblast to grow and proliferate and can enhance the expression of c-fos gene. The increase of c-fos gene's expression may be an important step in the signal transformation process of all kinds of stimulation boosting osteoblast to proliferate.

Animals↗

PubMedDate not supplied

Three-dimensional reconstruction of brain surface anatomy based on magnetic resonance imaging diffusion-weighted imaging: a new approach.

Fifty normal noninfarct patients and 12 cases with infarcts of the cerebrum were examined with routine magnetic resonance imaging and echo-planar diffusion-weighted imaging. The diffusion-weighted three-dimensional images were reconstructed with volume-rendering processing on workstation. Precentral gyrus, postcentral gyrus, superior parietal lobule, superior frontal gyrus, precentral sulcus, central sulcus, postcentral sulcus, intraparietal sulcus and superior frontal sulcus were best shown of all structures with an arbitrary score of 2.61-2.77. Supramarginal gyrus, middle frontal gyrus, inferior frontal gyrus and lateral sulcus were clearly shown in the majority of the cerebra with average scores of 2.0-2.49; angular gyrus, inferior frontal sulcus and superior temporal gyrus were not demonstrated satisfactorily and their average scores were 1.67-1.89. Middle temporal gyrus, inferior temporal gyrus, superior temporal sulcus and inferior temporal sulcus were difficult to identify, and thus had average scores of 0.87-1.26. Brain surface structures were better displayed in the older group of individuals than in the younger group. The structures in the 12 cases with acute or chronic cerebrum infarcts were also satisfactorily demonstrated with this new technique.

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