There is a high risk of re-stenosis after implanting blood vessels stent,the processes involves the transforming growth factor-β (TGF-β)-Smad signaling pathways,epithelial-mesenchymal transition (EMT) and so on.The function of TGF-β-Smad signal pathways and EMT in vascular stent re-stenosis and the relevant mechanism were reviewed in this paper.

With the development of drug discovery, more and more candidate compounds need to be studied. Methods that can screen compound rapidly received significant attention. Parallel artificial membrane permeability assay (PAMPA) as a powerful tool has been applied to drug studies. It uses an artificial lipid membrane to mimic the barrier for drug permeability studies. This article introduces the establishment and characteristics of PAMPA, as well as its applications in screening compounds. It can be used as models (e.g. predicting the ability of compound in gastro-intestinal absorption, blood-brain barrier transportation and skin penetration) by changing the component of artificial lipid membrane. PAMPA has advantages in high throughput selection of valuable compound with low cost, versatile, low dose, and good reproducibility.

A BASIC program was written to analyse the data from radioreceptor assay by microcomputer. Concentrations of ligand, total binding, nonspecific binding, specific binding and the ratio of specific binding (number of receptor sites) to free ligand content were calculated for each point. The receptor binding affinity constant and binding capacity were obtained by Sca-tchard analysis. Results and graphs can be displayed on the screen and/ or printed out by using a graphic printer

OBJECTIVEThis study aims to evaluate the optical data of the different sites of the cobalt-chrome (Co-Cr) alloy abutments covered by four different all-ceramic crowns and the color difference between the crowns and target tab using a digital dental spectrophotometer.

METHODSTen Co-Cr alloy abutments were made and tried in four different groups of all-ceramic crowns, namely, Procera aluminia, Procera zirconia, Lava zirconia (Lava-Zir), and IPS E.max glass-ceramic lithium disilicate-reinforced monolithic. The color data of the cervical, body, and incisal sites of the samples were recorded and analyzed by dental spectrophotometer. The CIE L*, a*, b* values were again measured after veneering. The color difference between the abutments covered by all-ceramic crowns and A2 dentine shade tab was evaluated.

RESULTSThe L* and b* values of the abutments can be increased by all of the four groups of all-ceramic copings, but a* values were decreased in most groups. A statistical difference was observed among four groups. After being veneered, the L* values of all the copings declined slightly, and the values of a*, b* increased significantly. When compared with A2 dentine shade tab, the ΔE of the crowns was below 4.

CONCLUSIONFour ceramic copings were demonstrated to promote the lightness and hue of the alloy abutments effecttively. Though the colorimetric baseline of these copings was uneven, veneer porcelain can efficiently decrease the color difference between the samples and thee target.

Ceramics ; Chromium Alloys ; Cobalt ; Color ; Colorimetry ; Crowns ; Dental Materials ; Dental Porcelain ; Dental Prosthesis Design ; Humans ; Metal Ceramic Alloys ; Titanium ; Zirconium

BACKGROUND:Shear mechanical properties of lumbar trabecular bone should be understood in treating osteoporosis,bone remodeling,bone reconstruction,as well as the choice of fracture fixed equipment.OBJECTIVE:To explore whether the shear mechanical properties of lumbar trabecular bone is different in young and aged normal fresh cadavers.METHODS:Experimental samples were from 4 normal fresh corpse,aged 22,28,70 and 75 years,were provided by Department of Anatomy,Norman Bethune Medical University.Spinal column thoracic vertebra L_2-L_5 specimen were obtained from corpse within 1 hour and cut into 40 min×5 mm×5 mm pieces.The specimen were tested on electronic universal testing machine with speed of 5 mm/min,the shear load,stress,strain and other data would be printed automatically,and the morphology of fracture surface was observed.RESULTS AND CONCLUSION:Majority of the fracture surfaces were comminuted,minority were transverse or oblique fracture.The macroscopic observation showed that trabecular arranged compact in the thoracic vertebra cancellous bone of the youth group,which was sparse arrangement and presented with senile osteoporosis in the aged group.The shear force,shear stress and strain of the youth group was greater than that of the aged group[(37.19±3.25),(28.34±3.42) N;(1.49+0.13),(1.13±0.14) MPa;(1.40±0.50)%,(0.90±0.20)%,P＜0.05].It demonstrated that the impact mechanics properties of thoracic vertebra cancellous bone are different between the youth and aged groups.

BACKGROUND:The brachial plexus injury anastomosis suture technique is necessary to understand the mechanics characteristic of brachial plexus nerve stress relaxation.Previous studies mainly focused on single tension mechanics of brechial plexus nerve,but few studies concerning stress relaxation and creeping elasticity.OBJECTIVE:To observe and analyze experimental animal brachial plexus nerve stress relaxation mechanics characteristic in the description manner of function,to provide experimental parameters for clinic.DESIGN,TIME AND SETTING:The experimental observations to use function as a way to describe from 1~(st) to 10~(th_ March,2007 at the Experimental Center of Jilin University.MATERIALS:The experimental male Sprague Dawley rats aged 6 months were provided by Changchun Gaoxin Medicine Animal Experimentation Center.METHODS:The stress relaxation experiment was performed in Experimental animal Brachial plexus Nerve on the the electronic universal testing machine (Shimadzu,Japan).The stress relaxation experiment strain increased speed was 1%/s,setting time of 7 200 seconds.100 empirical data were collected and disposed by one-way linear regression analysis.MAIN OUTCOME MEASURES:The stress relaxation data and curve,the Stress and time change rule were measured.RESULTS:The stress relaxation quantity of animal brachial plexus nerve test specimen at 7 200 s was 0.316 MPa.Stress relaxation curve changed with logarithm.Stress relaxation changed rapidly at 600 seconds,decreased gradually,and reached a balance level at 7 200 seconds.CONCLUSION:The stress relaxation curve changed with the logarithm relations.Brachial plexus has visco-elastic mechanical properties.

Objective To determine whether fetal rats exposure to isoflurane will cause postnatal learning and memory deficits,and change Bcl-2/Bax ratio in the hippocampus CA1 and retrosplenial cortex in fetal brain of rats. Methods Twenty-eight Sprague Dawley pregnant rats at gestation day 21 (E21) were randomly divided into isoflurane treatment group(n=14) and sham control group(n=14). Rats in isoflurane treatment group were ex-posed to 1.3% isoflurane in a carrying gas of 30% oxygen, balance nitrogen for 6 h in a warmed, humidified cham-ber. For sham control group,animals were treated at the same condition with only carrying gas. In behavior study,the spatial learning and memory ability at juvenile ages was determined with the Morris Water Maze(MWM). In immunohistochemistry study,changes of Bcl-2 and Bax expression in hippocampus CA1 and retrosplenial cortex in the fetus brain after isoflurane treatment at 2 hours was performed by using immunofluorecence staining.Results In the MWM training, the escape latency to platform in the place trials showed no significant difference between the two groups,but the postnatal rats in 1.3% isoflurane group showed obviously improved retention of memory by spending more percentage of time swimming in the probe quadrant as compared to the control animals ((42.33±2.31) s vs (33.2±2.15) s, t=2.21, P<0.05) in the probe test. Compared to controls, 1.3% isoflu-rane exposure for 6 h to the pregnant rats increased the intensity of Bcl-2, decreased the intensity of Bax, and sig-nificantly increased the Bcl-2/Bax ratio in the fetal hippocampal CA1 region (4.40±0. 86 vs 1.31±0.32, t=3. 378, P<0.01) and the fetal retrosplenial cortex (5.07±1.27 vs 1.47±0.48, t=2.656, P < 0.05) respec-tively. Conclusion 1.3% isoflurane exposure in pregnant rats significantly improves the spatial retention memo-ry of their rat pups at a juvenile age and increases the Bcl-2/Bax ratio in the hippocampal CA1 region and the ret-resplenial cortex in the fetal rat brains.

To study the drug-drug interaction of morinidazole and warfarin and its application, a sensitive and rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of R-warfarin/S-warfarin in human plasma. In a random, two-period crossover study, 12 healthy volunteers received a single oral dose of 5 mg racemic warfarin in the absence and presence of morinidazole. Blood samples were collected according to a pre-designed time schedule. R-warfarin, S-warfarin and methyclothiazide were extracted with ethylether : methylenechloride (3 : 2), then separated on a Astec Chirobiotic V (150 mm x 4.6 mm ID, 5 microm) column using 5 mmol x L(-1) ammonium acetate (pH 4.0) - acetonitrile as mobile phase at a flow-rate of 1.5 mL x min(-1). The mobile phase was splitted and 0.5 mL x min(-1) was introduced into MS. A tandem mass spectrometer equipped with electrospray ionization source was used as detector and operated in the negative ion mode. Quantification was performed using multiple reaction monitoring (MRM). The resolution of warfarin enantiomers is 1.56. The linear calibration curves for R-warfarin and S-warfarin both were obtained in the concentration range of 5 - 1 000 ng x mL(-1). Intra- and inter-day relative standard deviation (RSD) for R-warfarin and S-warfarin over the entire concentration range across three validation runs was both less than 10%, and relative error (RE) ranged from -4.9% to 0.7%, separately. The method herein described is effective and convenient, and suitable for the study of metabolic interaction between morinidazole and warfarin. The results showed that coadministration of warfarin with morinidazole did not affect the pharmacokinetics of either R-warfarin or S-warfarin.

To study the metabolite excretion of theophylline, a rapid and specific method by liquid chromatography with heated electrospray ionization tandem mass spectrometry (LC-HESI/MS/MS) method for simultaneous determination of theophylline, 1, 3-dimethyluric acid (1,3-DMU), 3-methylxanthine (3-MX) and 1-methyluric acid (1-MU) in human urine was developed using theophylline-d6 and 5-fluorouracil as internal standards. Selected reaction monitoring (SRM) with heated electrospray ionization (HESI) was used in the negative mode for mass spectrometric detection. After diluted with methanol and centrifuged, the analytes and ISs were separated on a XDB-Phenyl (150 mm x 4.6 mm, 5 microm) column with a mixture of water-methanol-formic acid (30 : 70 : 0.15) as mobile phase at a flow rate of 0.6 mL x min(-1). The linear calibration curves for theophylline, 1, 3-DMU, 3-MX and 1-MU were obtained in the concentration range of 1.0-250 microg x mL(-1), separately. The method herein described is effective and convenient, and can be used for determination of theophylline and its three metabolites. The results showed that urinary excretion ratio of theophylline, 1,3-DMU, 3-MX and 1-MU is approximately 1 : 3 : 1 : 2 in Chinese subjects, which is similar to the reported excretion pattern in Caucasian.

BACKGROUND:Hydroxyapatite-coated titanium substrates improve the biocompatibility and have the property of intimating ossteointegration with host bonebed. However, hydroxyapatite lacks the necessary mechanical strength and degrades easily in the extracelular fluids, which may affect the stability of the titanium implant.
OBJECTIVE:To study the synthesis and characterization of lanthanum-incorporated hydroxyapatite coatings.
METHODS: Lanthanum-incorporated hydroxyapatite coatings were prepared by hydroxyapatite and 10%, 20% and 30% lanthanum, respectively, by means of sol-gel, which were then deposited on titanium substrates with dip-withdrawal technique. Surface morphology and crystaline microstructure of the coatings were observed by scanning electron microscope. The presence of functional groups for the obtained samples was performed by Fourier transform infrared absorption spectroscopy and X-ray diffraction. The Ca2+ concentration released from the coatings was measured by atomic absorption spectrometry for analysis of degradation property.
RESULTS AND CONCLUSION: With the increase of lanthanum content, the diffraction peak and crystalinity of lanthanum-incorporated hydroxyapatite coatings were increased, but the whole structure of lanthanum-incorporated hydroxyapatites had little changes. The crystal structure maintained stable with charge balance. The lanthanum-incorporated hydroxyapatite coatings showed uniform and high-dense structure and were free of cracks, indicating the coatings had good bonding strength. Under the simulated biological environment, based on the determination of Ca2+ release from the coatings, we can conclude the lanthanum-incorporated hydroxyapatite coatings have a stronger acidoresistance.