BACKGROUND: The design of the microstructure of human bone is in fact to construct a model, which could characterize the connecting-porosity cell frame structure. As the porosity structure is represented as irregular curve, and this irregularity has close relationship with the bone function, does the fractal theory effectively find the irregularity containing in the irregular structure?OBJ ECTIVE: To analyze the microstructure of human bone by applying the fractal property, and construct the 3D model that has structural similarity to the natural bone. With the help of Rapid Prototyping technology, a new bionic technique instead of traditional modeling method is presented to model artificial human bone.DESIGN: Computer aided bionic design.SETTING: Biomaterials and Engineering Center of Wuhan University ofTechnoiogy.MATERIALS: The experiment was carried out in the Biomaterials and Engineering Center of Wuhan University of Technology from January to June 2005. The material is the original gray chart of hip joint of one healthy middle-aged male.METHODS: The contour of the human bone microstructure was obtained by exaltation and extraction of the grey chart.B-spline technique was used for vectorization. ①The fractal theory was adopted to compute the fractal dimension of typical aperture structure and the result was represented by dimensions (D=2s, s is the slope of fitting line) to find the inherent relation among apertures. ② Monte Carlo method was used to generate the two-dimensional model of microstructure of bone with the appropriate porosity. The 3D model was manufactured by rapid prototyping technology.MAIN OUTCOME MEASURES: ①Fractal dimension of porous structure of human bone; ② Results of 2D and 3D model of the microstructure of human bone.RESULTS: ①The fractal dimensions of some representative apertures were between 1.14and 1.28. The fractal dimensions of these micro-apertures are rather close, which testified the self-similarity in the edge contour of the microstructure of human bone. ②3D model was generated by cumulating the plane model layer by layer with the rapid prototyping technology. If the high porosity of plane model was ensured, the porosity and connectivity of 3D model could meet the high requirement. Through the computer simulating, the porosity of the model was greater than 40%, which meets the design requirement.CONCLUSION: Fractal theory is applied in the construction of 2D model of human bone based on the requirements in bionic design of the microstructure model of human bone. The fractal characteristics of the grey chart of human bone and the edge contourof its typical micropore are analyzed. The software suitable for 2D tissue engineered bionic microstructure of human bone is developed with VC++, meanwhile, 3D cell scaffold model is constructed by cumulating the planer model, which meets the human bone functions.

BACKGROUND:Domestic scholars use the potentiodynamic polarization technique to determine the corrosion potential of the dental aloys, which is used to evaluate the corrosion performance of the lownoble metal. They have discovered that the main reason affecting corrosion resistance is the content of noble metal. OBJECTIVE:To evaluate the corrosion resistance of Ti, Au aloy, Co-Cr aloy, Ti aloy, and Ni-Cr aloy. METHODS: Five aloys were immersed in synthetic saliva solution. The corrosion potential and corrosion current density of the aloys were determined with potentiadynamic polarization technique. RESULTS AND CONCLUSION:The galvanic series of five kinds of aloys were ranged as folows: Au aloy > pure Ti > Ti aloy > Co-Cr aloy > Ni-Cr aloy. Au aloy and pure Ti had more positive potential that were not easy to produce corrosion; Ti aloy and Co-Cr aloy could form stable oxidation film with a strong ability of anti-pitting and crevice corrosion; Ni-Cr aloy potential was more negative and easy to be dissolved. The corrosion current density of five kinds of aloys was ranged as folows: Au aloy < pure Ti < Ti aloy < Co-Cr aloy < Ni-Cr aloy. Au aloy and pure Ti had lowest current density which was 10-8, indicating that the corrosion rate of Au aloy and pure Ti was lower; in contrast, Ni-Cr aloy possessed the maximum corrosion rate. These findings indicate that Au aloy and pure Ti exhibit a very high corrosion resistance. The corrosion rate of Ni-Cr aloy is the highest; therefore, Ni-Cr aloy is the least acceptable material for implant suprastucture.

Stroke is one of the major diseases that threaten human health, early diagnosis and treatment are very important for stroke. Carotid intima-media thickness (CIMT) is measured noninvasively to diagnosis stroke, and it is a independent predictor for stroke because its thickening can timely predict the incidence and development of stroke. As an important predictor of cardiovascular disease, more and more attention is played on CIMT. In this review, we will make a summary on the important role of CIMT in stroke and the mechanisms of carotid intima-media thickening in stroke as well as the potential use of traditional Chinese medicine in treating carotid intima-media thickening.
Animals ; Carotid Arteries ; drug effects ; physiopathology ; Carotid Intima-Media Thickness ; Drugs, Chinese Herbal ; therapeutic use ; Humans ; Stroke ; diagnosis ; drug therapy ; physiopathology

Objective: To compare the pharmacokinetics and relative bioavailability of rapid oral disintegrating tablet of dimenhydrinate (RODTD) and those of market available tablet of dimenhydrinate (DMH). Methods: Eight healthy volunteers were evenly randomized into 2 groups, one group received RODTD (25 mg) and the other received available market tablet of dimenhydrinate (25 mg). The blood levels of DMH were determined by high performance liquid chromatography (HPLC) before and after drug administration in 2 groups. Chromatography conditions were: Nova-Pak C18 as chromatographic column, methanol triethylamine buffer (1 : 1),flow rate: 1.0 ml/min, detection wavelength: 225 nm, and room temperature. The pharmacokinetics and relative bioavailability of RODTD and market available tablets were investigated. Results: The standard curve of DMH in the blank plasma was linear within the range of 5-500 ng/ml, with the regression equation being C=0.004 4 A+4.745 and R2=0.996. The limit of detection was 2 ng/ml; the average recovery rate was (90.55±4.69)% and the RSD was 0.041%. The intra-day derivations of 3 different concentrations (low, middle, and high) of plasma were 9.27%, 4.93%, and 2.95%, respectively (n=5), and the inter-day derivations were 9.97%, 3.81%, and 3.06%, respectively (n=5). Blood samples (3 ml) were subjected to HPLC assay and significant difference was found between the 2 forms of DMH. The pharmacokinetic parameters of RODTD were: AUC=(602.04±113.82) ng • h • ml-1, Cmax=(95.86±21.28) ng • h • ml-1, and TPeak=(1.8±0.32) h; the pharmacokinetic parameters of market available tablets were: AUC=(342.73±84.96) ng • h • ml-1 Cmax=(46.34± 10.32) ng • ml-1, and TPeak=(2.65±0.24) h. Statistical analysis showed there was significant difference in the relative bioavailability of 2 forms of DMH(P<0.01). The relative bioavailability of RODTD to market tablet was 175.66%. Conclusion: The developed RODTD can obviously increase the relative bioavailability of DMH.

Cardiovascular Diseases ; drug therapy ; prevention & control ; Humans ; Hypolipidemic Agents ; administration & dosage ; therapeutic use ; Risk Reduction Behavior

Animals ; Antibodies, Helminth ; blood ; cerebrospinal fluid ; Child, Preschool ; Eosinophilia ; cerebrospinal fluid ; diagnosis ; etiology ; Female ; Humans ; Meningitis ; cerebrospinal fluid ; diagnosis ; etiology ; Neurocysticercosis ; complications ; drug therapy ; parasitology ; Taenia ; immunology

Adult ; Anemia, Aplastic ; complications ; surgery ; Female ; Hematopoietic Stem Cell Transplantation ; Hemoglobinuria, Paroxysmal ; complications ; surgery ; Humans

Coronary Disease ; drug therapy ; Humans ; Hypolipidemic Agents ; administration & dosage ; therapeutic use

Objective To compare the therapeutic effect of routine dose of calcitriol and large dose impulsion therapy on hemodialysis patients with secondary hyperparathyroidism(SHPT). Methods 48 uremic hemodialysis patients were divided into group A(routine group, n = 22) and group B(control group, n = 21 ). In group A,22 pa-tients were administered with calcitriol for 6 months at the dosage of 0.25～0.5μg/d,adding calcium agents simul-taneously;the patients in group B were not given calcitriol for economic reason. In group C,21 patients were given calcitriol twice a week at the dosage of 2μg/time after hemodialysis for 3 months. Results Comparing to group B,serum PTH,AKP in group A had no significant difference,but serum hypocalcium and hyperphasphate were partly corrected,symptoms of bone pain, muscular convulsion and akin pruriter were improved. Comparing to group A,serum hypocalcium and hyperphasphate in group C were corrected, serum PTH, AKP were significantly decreased( t=2.031,P<0.05;t =3.317,P<0.001),and no hypercalcium oecurred. Conelosion Routine dose of calcitriol can not control uremic-SHirr,while impulsion therapy with lower dose oral calcitriol is effective and safe.

Acupuncture Points ; Acupuncture Therapy ; instrumentation ; Catgut ; Female ; Humans ; Infertility, Female ; blood ; therapy ; Moxibustion ; Treatment Outcome