Biomedical subjects

Yubo Fan

Publications and source records attributed to Yubo Fan.

28 records · Page 2Linked to original sources

PubMed2003

[Effects of static tension-stress and TGF-beta 1 on proliferation of mandibular condylar chondrocytes].

OBJECTIVE: The purpose of this study was to investigate effects of static tension-stress and TGF-beta 1 on proliferation of mandibular condylar chondrocytes in vitro. METHODS: The fourth-passage chondrocytes were harvested from the mandibular condyles of 2-week-old SD rats for this study, and a cellular static tension-stress device was used to apply stress on cells. The effects of continuous static tension-stress and/or transforming growth factor-beta 1 (TGF-beta 1) on the proliferation of mandibular condylar chondrocytes were examined using flow cytometry. The experiment was divided into two parts. The first part consisted of 100 specimens which were divided into 20 groups with different TGF-beta 1 dosage (0 ng/ml, 0.1 ng/ml, 1 ng/ml and 10 ng/ml) for 0, 6, 12, 18 and 24 hours respectively. The second part consisted of 30 specimens which were divided into six groups under continuous static tension-stress (5 kPa) and different TGF-beta 1 dosage (0.1 ng/ml, 1 ng/ml, 10 ng/ml) for 0, 6 and 12 hours. Multivariable analyses were conducted to test for associations between proliferation of mandibular condylar chondrocytes and TGF-beta 1 and/or different stresses. RESULTS: The results showed that TGF-beta 1 had a mitogenic effect on rat mandibular condyle at the concentrations of 0.1, 1 and 10 ng/ml, and the mitogenic effects of TGF-beta 1 on condylar chondrocytes were demonstrated in 12 to 18 hours after application of stresses, and the peak of mitogenic effects appeared at 18 hour (P < 0.05). The most active mitogenesis happened in the group with continuous static tension-stress (5 kPa) combined with TGF-beta 1. CONCLUSION: These results prove mechanical stimulates and TGF-beta 1 in vitro could influence and regulate the growth of condylar chondrocytes.

Animals↗

PubMed2003

[Biological characteristics of human umbilical artery smooth muscle cells cultured in vitro and the preestablishment of immortalized cell line].

OBJECTIVE: To establish the best primary and propagated culture approach of the human umbilical artery smooth muscle cells (HUASMC) and immortalized the primary cells. METHODS: The primary culture of HUASMC was performed using the primary-explant method, and the effects on the cells' growth characteristic by different culture mediums were conducted. Primary cultures of HUASMC derived from normal human umbilical arteries were transfected with recombination plasmid containing human telomerase reverse transcriptase (hTERT) open reading frame. The transfected HUASMC was analyzed for cell biological characteristics, and growth characteristics, and specific alpha-actin. RESULTS: Highly purified primary HUASMC were gained and could be propagated about 10 population doublings (PD). After PD 4, the cells lost the proliferation ability gradually. However, the transfected HUASMC could be propagated at least 20 population doublings and could express specific alpha-actin. CONCLUSION: The hTERT transfected HUASMC could keep the basic biological characteristic of smooth muscle cells and prolonged life span at least 20 PD. It might be a good cell model for the study of cardiovascular disease, myoma of uterus and chronic graft disfunction. It might also bring the hope to engineered vascularization in the future.

Cell Line↗

PubMed2003

[Morphological parameters for endothelial cells under shear stress].

Shear stresses acting on vascular endothelial cells due to blood fluid flow play an vital role in regulating their morphology, structure, growth rate and functions. The change in morphology is an instinctive response to biomechanical environment and is an indicator for the functional changes in the cells. In this paper, the morphological research literatures of endothelial cells in the recent years are reviewed and the common morphological parameters are described in detail. At the end, the difficulties of quantitative study of endothelial cell morphology and the future direction of morphological parameters research are also discussed.

Animals↗

PubMed2003

[The 3D finite element stress analysis of transtibial monolimb].

In this study, a 3D model of a transtibial monolimb and residual limb was constructed. The stresses on all nodes of the model under the simulus of the load at the Mid-Stance were computed through 3D finite element analysis (FEA). The stress distribution on the internal and external surfaces of the model was obtained. The results indicate that the stresses on socket are lower than those on prosthetic shank; high stress regions are located on the underneath of prosthetic shank and the border section of socket and prosthetic shank. These data will be useful for CAD\CAM system of monolimb designing.

Artificial Limbs↗

PubMed2002

How electron flow controls the thermochemistry of the addition of olefins to nickel dithiolenes: predictions by density functional theory.

The reaction of a nickel dithiolene complex (1) and ethylene is a two-step process, in which the trans-product (2) forms first in the direct addition of the olefin to 1, while the more thermodynamically stable cis-product (3) involves isomerization of 2. The introduction of electron-withdrawing groups (cyano or trifluoromethyl) not only significantly lowers the activation energy (TS1) for the formation of trans-product, but it also strongly stabilizes the products (2, 3) such that they are favored by the free energy. However, these substituents leave the barrier for the conformational transformation step (TS2) nearly unchanged. On reduction, the previously favored adduct is now strongly disfavored.

Journal Article↗

PubMed2002

[Studies on biomechanics of human foot: a review].

The plantar pressure and shear force measurement, the function and effect of joints, bones and ligaments of foot during running and walking, and the modeling and finite element analysis of human foot are three important aspects in biomechanical study of foot. They are also the basis of the study of rehabilitation. In this paper, studies on the three aspects are reviewed, and further promising developments are proposed.

Biomechanical Phenomena↗

PubMed2002

[Three-dimensional finite element analysis on cell culture membrane under mechanical load].

A three-dimensional finite element model of the cell culture membrane was developed in the culture device under tension state made by us. The magnitude of tension and the displacement distribution in the membrane made of silicon rubber under different hydrostatic load were obtained by use of FEM analysis. A comparative study was made between the numerical and the experimental results. These results can serve as guides to the related cellular mechanical research.

Animals↗

PubMed2002

[A methodological study of measuring quantitatively turbulent shear stree downstream of mitral stenosis in vivo using Doppler echocardiography].

In order to establish a method for measuring quantitatively turbulent shear stress (TSS) downstream of mitral stenosis in vivo based on Doppler echocardiography and computer-aided image analysis, we used doppler echocardiography to record the spectrum of flow velocity downstream of mitral valve at several locations in normal persons and in patients with mitral stenosis. With the computer-aided analysis of spectrum images, the magnitude of TSS was measured at the locations. The results demonstrate that no matter how severe the mitral stenosis is, the TSS and relative turbulent intensity(Irel) at the central locations of jet are lower than those at the marginal ones. A significant difference in the quantitative items of TSS, Irel and flow field uniformity between normal persons and patients with varying-degree of mitral stenosis was noticed (P < 0.05). There was a significant correlation between these items and effective orifice area (EOA), and we found that the smaller EOA is, the more severe the extent of stenosis is and the greater the magnitude of both TSS and Irel are, and that the highest magnitude of TSS is focused on the marginal area of jet. These results indicate that there is an obvious correlation between TSS(measured by Doppler echocardiography combined with computer-aided image analysis) and flow field uniformity. They can coincidently reveal the hemodynamic changes resulting from mitral stenosis of varied severeness, implying that our method could exactly depict the magnitude of TSS downstream of mitral stenosis in vivo and is non-invasive and good for anti-disturbance. The method can be used to analyze quantitatively TSS in the flow field of heart valve in patients with valvular diseases.

Adult↗

PubMed2002

[Finite element analysis of DAI animal model caused by nonimpact with half bound head in cats].

This study sought to make a biomechanical analysis of the diffuse axonal injury(DAI) animal model caused by nonimpact with half bound head in cats. A three-dimensional finite element model of cat's head was established. The head of an anesthetized cat was scanned in 2 mm section. The nods and element meshes were signed out according to the geometry of every section. The geometric data were put into the computer and the element mesh body of cat's head was established in vizi CAD system. The maximum stress, minimum stress and von Mises stress were calculated by Super SAP (93ed) finite elemental software when the force was loaded on the right or left side of model in zero section. The analysis showed that the maximum stress appeared in the anterior and posterior loaded point and extended to cranial base in the cranial shell. There was high stress in the brain surface also. Because of cerebellar tentorium, cerebral falx, petrosal bone and sellar process, the stress did not decrease equivalently while approaching the deep brain, but it was distributed in cerebral-cerebellar peduncles, brain stem, corpus callosum and basal ganglia area at high values. The results suggest that the stress caused by rotational force is widespreadly and unequivalently distributed in brain tissue, which is mainly effected by the cerebellar tentorium, cerebral falx and the irregular geometric forms of cranial bone.

Animals↗

PubMed2002

[Experimental methods for mechanically stimulating the cells in vitro].

Cellular mechanics is a branch of tissue engineering and cellular engineering. As one of the important method, loading different mechanical stimuli to culturing cells in vitro so as to study the influence that the stress has on the cells is one of the important fields of cellular mechanics. This paper reviews the experimental methods for mechanically stimulating the cells in vitro, according to the different loading modalities, the methods can be categorized into micropipette aspiration, compression loading, substrate distention, fluid shear, etc. And it also points out their advantages and disadvantages.

Cell Culture Techniques↗