OBJECTIVE:To prepare medicinal water-based magnetic fluid and to study its cyto-compatibility.METHODS:Medicinal water-based magnetic fluids were prepared with microemulsion preparative technique by an one-step surface acting agent management method,the appearances and size distributions of which were detected by transmission elec-tron microscope and photon-related spectrograph.The influences of different concentrations of magnetic fluids on the in vitro cyto-compatibility of normal human liver cell strain(L-02)were detected by methyl thiazolyl tetrazolium(MTT)colorimetric assay and lactate dehydrogenase(LDH)delivery test,respectively.The characterization of the prepared solid magnetic fluid samples coated with monolayer and bilayer capric acid were conducted by infrared spectrometry,thermogravimetry,differential thermogravimetry and differential scanning calorimetry.RESULTS:The results showed that the grain size of the medicinal water-based magnetic fluids ranged from10nm to20nm.Phase separation or marked change in mean particle sizes were failed to be noted after storage for1year.The MTT and LDH tests results showed that medicinal water-based magnetic fluids were of no cytotoxicity to L-02but have good cyto-compatibility.CONCLUSION:Medicinal water-based magnetic fluids can be used in magnetic targeting drugs delivery system.

Objective To investigate biomechanical characteristics of flexor profundus tendon repaired by modified Kessler or Tsuge technique in the early of postoperative period, and to discuss the feasibility of using two techniques in flexor tendon repair in order to proceed early active or passive mobilization protocols. Methods 42 Sanhuang cocks were randomly divided into two groups. The second and fourth flexor digitorium profoundus tendons of cocks were severed at the middle phalanx transversely and repaired by modified Kessler or Tsuge technique respectively, postoperative plaster cast immobilization was maintained for 3 weeks. The repaired tendons were harvested at 7 time intervals-immediately after repair, 1, 4, 7, 10, 14, 21 days after operation and stored at  20 ℃ in a refrigerator until biomechanical test. A tensile strength-elongation curve was obtained for each tendon sample. Biomechanical parameters including tensile strength of rupture and elongation ratio of rupture were calculated from the curve automatically by testing machine. SPSS software was used for statistical analysis. Independent-samples t test for inter-group comparison; One way ANOVA and SNK q test for inter-group comparison. Results The tensile strength of rupture dropped to the lowest level between 10th and 14th day and resumed its original level immediately after repair at 21st day in modified Kessler group; while in Tsuge group, it decreased at 10th day, then slowly rised up at 14th day but still didnt reach the original level at 21st day. There was no significant difference between two repair methods after 4th day after operation. The elongation ratio of rupture was lowered significantly since 7th day in modified Kessler method, but 4th day in Tsuge method and decreased consistently until 3 weeks postoperatively. There was no significant difference between the two suture methods at any time-intervals. Conclusion The rather high biomechanical characteristics of Tsuge method loses quickly in the early period of tendon healing and resumes slowly; Modified Kessler method maintains its biomechanical properties at all time-intervals except 10th day.

The properties of polyethyleneimine-cholesterol cationic lipopolymer (PEI-Chol) as gene carries and its gene transfer efficiency in vitro with lipid microbubbles were presented in this paper. PEI-Chol lipopolymer was synthesized by linking cholesterol chloroformate to the amino groups of branched poly(ethyleneimine) (PEI) of 1 800. The structure and molecular weight of PEI-Chol were confirmed by IR, 1H NMR and MADI-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry), respectively. The average molecular weight of PEI-Chol was approximately 2 000. The gene delivery system of bubble/PEI-Chol/DNA was constructed by mixed PEI-Chol/pDNA (N/P 10:1) complexes with lipid microbubbles (2-8 microm) which were prepared by DPPC, DSPE-PEG2000 and perfluoropropane with the reverse phase evaporation technique. pEGFP-Cl (enhanced green fluorescent protein) was used as report gene to investigate the DNA condensing ability of PEI-Chol lipopolymer by agarose gel electrophoresis. And their cytotoxicity and in vitro transfer efficiency of different complexes were compared with each other in A549 and MCF-7. The results indicated PEI-Chol lipopolymer can condense plasmid DNA when N/P ratio upto 4, PEI-Chol complexes and bubble/PEI-Chol/DNA complexes were nontoxic to A549 and MCF-7 when formulated at the N/P ratio of 10/1 as determined by MTT assay. This bubble/PEI-Chol/DNA delivery system provided good transfer efficiency with other desirable characteristics such as against-precipitation of plasma proteins. In conclusion, bubble/PEI-Chol/DNA complex is a novel non-viral gene delivery system.

Objective To compare the biomechanical stabilities of 2 fixations for oblique split fractures of tibial plateau. Methods Oblique split fractures of the medial tibial plateau were simulated by osteotomy in 6 pairs of fresh tibia of adult swine. One fracture of each pair was fixed with 3 lag screws parallel to the articular surface whereas the contralateral site was stabilized with 3 lag screws vertical to the fracture line. The maximum anti. Compression load, the maximum power consumption at the maximum load.the load and power consumption at the 2 mm subsidence of articular surface were measured and recorded. Results There were no significant differences between the 2 groups in the maximum anti-compression load. The maximum power consumption at the maximum load, the load and power consumption at the 2 mm subsidence of articular surface. Conclusion Vertical fixation may not provide a biomechanical advanrage over the parallel fixation in stabilizing oblique split fractures of tibia plateau.

MF.

Aim To study the distributive character of mitomycin(MMC) magnetic nanoparticles and MMC normal saline solution in mice.Methods A HPLC method for the determination of MMC in tissues and serum were established and applied to determine MMC in biological samples.Results Under the guidance of an external magnetic field,targeting rates of MMC to liver viscus are 82.72% after 30 minutes tail vein administration of(1 mg?kg~(-1)) mitomycin magnetic nanoparticles,it was 2.37 times larger than targeting rates of MMC normal saline solution group.The distributions of heart and kidney of mitomycin magnetic nanoparticles were less than that of MMC normal saline solution group.Compared with the results of tail vein administration mitomycin nanoparticles,interaction between the external magnetic field and magnetic nanoparticles is significantly effective to increase targeting rates of MMC to liver.Compared with the results of tail vein administration mitomycin magnetic nanoparticles without the external magnetic field,Mitomycin magnetic nanoparticles under the guidance of an external magnetic field is significantly effective to increase targeting rates of MMC to liver.Conclusions Mitomycin magnetic nanoparticles under the guidance of an external magnetic field is significantly effective to increase targeting rates of MMC to liver and prolonging effect on the action in vivo.

OBJECTIVE:To prepare buspiron hydrochloride sustained-release tablets and to study its release characterization in vitro and the factors affecting drug release.METHODS:Buspiron hydrochloride sustained-release tablets were prepared with hydroxypropyl methylcellulose(HPMC)as hydrophilic gel-matrix material and ethylcellulose(EC)as retarder by wet granulation.The impacts of releasing transmitters,contents of HPMC and EC,and viscosity on the drug release in vitro of the tablets were studied.RESULTS:For the prepared sustained release tablets,the 24h drug release amount was over 90%,and the drug release curve conformed to Higuchi equation.The more contents of HPMC and EC and the higher viscosity of HPMC in the tablets,the slower drug release velocity was obtained;but the viscosity of EC and the releasing transmitters had no significant impacts on the drug release velocity.CONCLUSION:With HPMC and EC as matrix materials,the 24h continuous drug release is available for buspirone hydrochloride sustained-tablets.

OBJECTIVE:To optimize the preparation technology of Ginkgo biloba extracts-hydroxyprop-?-cyclodextrin(GBE-HP-?-CD) inclusion compounds and to identify this inclusion compound.METHODS:The optimum preparation condition was studied by orthogonal test with encapsulation rate as the index of evaluation.The inclusion compounds were prepared with solution-agitating technique.The inclusion compounds were identified by phase solubility diagra-m,differential scanning calorimetry(DSC) and infrared spectroscopy methods,respectively.RESULTS:The optimum inclusion condition was as follows:the ratio of GBE to HP-?-CD=1.5∶1;agitating time=6 h;inclusion temperature=50 ℃.CONCLUSION:It has been preliminarily proved that it is possible for Ginkgo biloba extracts and hydroxyprop-?-cyclodextrin to be made into inclusion compounds.HP-?-CD has satisfactory solublization on Ginkgo biloba extracts.

OBJECTIVE:To study the preparative methods of the long-circulating solid lipid nanoparticles(LSLN)carrying ginkgolides A and B(GAB)and to study the physicochemical characteristics of the GAB-LSLN.METHODS:GAB-LSLN was prepared by ultrasonication or high pressure homogenization.Transmission electron microscopy was employed to study its shape.Particle size,zeta potential,and entrapment efficiency of GAB-LSLN were determined,and its stability after storage under room temperature for 4 weeks was determined as well.RESULTS:The GAB-LSLN prepared by ultrasonication was platelet-shaped and irregular,and that prepared by high pressure homogenization was spherical and regular in shape.The particle diameters of GAB-L SLN prepared by ultrasonication and high pressure homogenization were(219.6?14.3)nm and(173.9?10.4)nm respectively(P0.05).CONCLUSION:High pressure homogenization is superior to ultrasonication in that the prepared GAB-LSLN has small particle size,high stability and high entrapment efficiency.