THE PREPARATION OF CROSSLINKED N,O-CARBOXYMETHYL CHITOSAN RESINSAND THEIR ADSORPTION PROPERTIESFOR TRIGLYCERIDE IN SERUM

Crosslinked N, O-carboxymethyl chitosan resins which can selectively adsorb triglyceride, were prepared by the reaction of N, O- carboxymethyl chitosan with glutaraldehyde solution. Adsorption experiments were performed by adding the resins to the serum. The results showed that this type of adsorbent could cut down the concentration of triglyceride in serum by 56. 4% (3. 35mg/gresin ) at most, while concentration of the total protein (TP ) decreased only by 10. 9% at least, so this novel adsorbent can be used to cure hypertriglyceridemia by hemoperfusion in the future.

Study on Biocompatibility of Cross-linked Hyaluronic Acid Derivatives

Objective:The cross-linked production,which was prepared by HA and cross-linking agent STMP,EDC,GP through cross-linking reaction,might be used in drug delivery system(DDS).To ensure the security of clinical application,the excellent properties such as none cell toxicity,nonirritant,none general toxicity,none immunological rejection are necessary.Methods:In accordance with the request of GB/T 16886.1 on security evaluation of medical biomaterials,cell toxicity test,hemolysis test,intracutaneous stimulation test,acute toxicity test,and hypersensitive test were required.Results:Cell toxicity of HA-STMP,HA-EDC,HA-GP were all less than 1.All hypersensitive tests were eligible.But HA-EDC,HA-GP produced different degrees of slight thrill,slight toxicity,hemolysis rate,which were larger than the standard value.Conclusion:HA-STMP possesses favourable biocompatibility,which is a kind of ideal biomaterials and drug carriers.

Study on Preparation of Temperature-sensitive Injectable Hydrogel

To get a sort of new scaffold material for soft tissue reconstruction,we have prepared XLHA-PNIPAAm and XLHA-MC injectable hydrogels through blending crosslinked HA(XLHA) and two temperature-sensitive materials differed in degradation poly(N-isopropylacrylamide)(PNIPAAm) and methylcellulose(MC),respectively.We tested the injectablility,enzymatic biodegradability,temperature-sensitivity,structure cytotoxicity and hemolysis of the two injectable hydrogels.Our research has successfully obtained the preparation condition of XLHA-PNIPAAm injectable hydrogel,and verified that adding non-degradable material PNIPAAm can postpone the degradation of HA more effectively than degradable material MC.PNIPAAm prepared with 5 kGy dose radiation,MBAAm/NIPAAm(M/M)=0.015,monomer concentration=3% produced XLHA-PNIPAAm with slowest enzymatic biodegradability.DSC results showed that temperature-sensitivity of the XLHA-PNIPAAm was more stable than that of XLHA-MC.Two composite hydrogels were qualified in cytotoxicity and hemolysis tests and the biocompatibility of XLHA-PNIPAAm hydrogel showed better than XLHA-MC hydrogel.

NH_2 Ion Implantations Induced Superior Cell Attachment of Carbon Nanotubes

Objective： Cell and platelet attachment on the multiwalled carbon nanotubes （MWCNTs） were studied by ion implantation. Methods： NH2 ion implantation was performed at the energy of 30 keV with the fluence of 1 x 1016 ions/era2 at room temperature. Results： The cell attachment tests showed interesting results in that the number of the platclets adhering on the surface of the MWCNTs was reduced significantly after NH2 ion implantation, whereas, mouse fibroblast cells （L929） cultured on NH2 ion implanted MWCNTs displayed higher cell-viability, proliferation, and stretching compared with MWCNTs. Conclusion： No appreciable change in the tensile strength and the optical transmittance of the implanted samples was observed. X-ray photoelectron spectroscopy （XPS） analysis showed that NH2 ion implantation caused the formation of new N-containing groups.

Study on the Surface Modification of Hydrophobic Polyacrylate Intraocular Lens

In this study, the polyacrylate intraocularr lens is irradiated by argon ion which can produce free radicals. In order to obtain better hydrophilic and lower platelets adhesion, monomer vinyl pyrrolidone (NVP) is grafted onto the hydrophobic polyacrylate intraocular lens surface in a certain reaction conditions. Specific changes in intraocular lens are detected by static contact angle (CA), scanning electron microscope (SEM) and light transmittance. The results show that this surface modification can greatly improve its hydrophilic character and surface formation.

In vivo Implantation of Hydrophobic Acrylic Intraocular Lenses with Surface Modification

Purpose:To assess the surface properties of modified hydrophobic acrylic intraocular lenses (IOL) implanted in rabbits.Methods:.The hydrophobic acrylic IOLs were modified with monomer vinyl pyrrolidone by surface modification technique.Phacoemulsification combined with IOL implantation was conducted in 9 rabbits (18 eyes).Postoperative responses were observed by slit-lamp microscope at 3,.7,.15,.30,.90 days after surgery.Results:.During the early stage after IOL implantation,corneal edema and anterior chamber fibrin exudation were observed.The exudate fluid was almost absorbed at the 15th day postoperatively.At 7th day,the anterior chamber exudation in the modification group was significantly less severe than that in non-modification group(P<0.05).Posterior capsular opacification occurred at 30th day after surgery and was aggravated90 days later.IOL dislocation was seen in 5 eyes and occlusion of pupil in 3 eyes.Conclusion:The hydrophobic acrylic IOLs with surface modification have improved surface properties and higher uveal biocompatibility.

Study on Characteristics of Acellular Bovine Pericardium Crosslinked with Genipin

The study used a naturally occurring crosslinking reagent-genipin to chemically modify acellular bovine pericardium, prepare cardiac valve tissue engineering scaffold material,and evaluated genipin crosslinked acellular matrix of bovine pericardium by investigating the physical and chemical properties of the tissues, such as the surface properties, crosslinking characteristics, mechanical properties, resistance to enzymatic capacity in vitro, and hemolysis tests. The results showed that acellular bovine pericardium matrix erosslinked with genipin was strong hydrophilicity, high crosslinking index, and stable structure, which can maintain good mechanical properties. As a kind of scaffold material for valve tissue engineering, it has wide application prospect.

Crosslinking of Bovine Pericardia Using Procyanidins

The aim of this study was to evaluate the crosslinking effect of a naturally crosslinking reagent-procyanidins （PA）-on the materials of bioprosthetic heart valves. After fixing bovine pericardial tissues by procyanidins, crosslikng characteristics, mechanical properties, in vitro enzymatic degradation resistance, the hydrophilicity and hemolysis tests were examined. The results showed that the fixation of biological tissue with glutaraldehyde （GA） or procyanidins increased its denaturation temperature, the surface hydrophilieity and mechanical properties as well as in vitro enzymatic degradation resistance. There were no significant differences in denaturation temperature, mechanical properties, the hydrophilicity and the in vitro enzymatic degradation between the glutaraldehyde and procyanidins fixed tissues. However, the ultimate tensile strength of the procyanidins fixed tissues was significantly superior to the glutaraldehyde fixed tissues. The hemolysis tests showed that hemolysis rate of the proeyanidins fixed tissues was lower than that of the glutaraldehyde fixed tissues. This study shows that procyanidins can crosslink which bovine pericardiaa effectively without toxicity. Our results suggest that this method might be a useful approach for the preparation of bioprosthetic heart valve.

Study on Biological Properties of HA-TMP Cross-linked Products

Objective:In the medium of ethanol(non-polar),STMP and ADH as crosslinkers to HA,to prepare drug delivery microspheres by getting stable cross-linked products without a gel phase,and to study biocompatibility and biodegradability of cross-linked products.Methods:ISO10993.1-Safety Evaluation of Biomedical materials as a reference,to make hemolysis test,percutaneous stimulation test,acute toxicity test,and analyze in vitro degradation test,and degradation products.Results:HA-STMP cross-linked product had no hemolysis,no irritation,no acute systemic toxicity,but HA-ADH had a mild skin irritation and adverse acute systemic toxicity.HA-STMP cross-linked product had lower sensitivity on HAse and the curve is flatting.With the increase of degradation time HA-STMP results were changed by the structure analysis,degradation products of these cells were no toxicity.Conclusion:HA-STMP cross-linked products with better biocompatibility and better resistance to hydrolysis could delay the degradation time,which is suitable for the preparation of biodegradable drug carriers.

Androgen Receptor Is a Tumor Suppressor and Proliferator in Prostate Cancer

Targeting androgens via androgen deprivation therapy (ADT) to suppress androgens/androgen receptor (AR) functions remains the standard treatment for prostate cancer. However, most tumors eventually recur

Dogs: Active Role Model for Cancer Studies—A Review

Many studies have been done and many results have been established for studying cancers in human and the ways of treating it. However, one thing that remains relevant is the study model that is used to diagnose, cure or conclude treatment methods for human cancers. The scientists have tried some ways to link the data and tried to analyze the malicious disease in various animal models in order to solve the problem for humans. Out of all the models, scientists have preferred dogs as the most suitable model and conducted studies on them. Our article will review the reason for preferences given to dog as a study model and what the previous studies have tried to conclude by considering the dreaded disease in dogs. Our article has focused on most of the recent observations and tried to elucidate the reasons/preferences for studying cancer disease in dogs (scientific name;Canis Lupus familiaris). We will also talk about the idea of comparative oncology programs that many centers adapt in order to study the disease called cancer.

In vitro comparison of the hemocompatibility of diamond-like carbon and carbon nitride coatings with different atomic percentages of N

Carbon nitride （CN,） and diamond-like carbon （DLC） coatings were prepared by dc magnetron sputtering at room temperature. Different partial pressures of N2 were used to synthesize CNx to evaluate the relationship between the atomic percentage of ni- trogen and hemocompatibility. Auger electron spectroscopy and atomic force microscopy indicated atomic percentages of N of 0.12 and 0.22 and that the CNx coatings were smooth. An in vitro study of the hemocompatibility of the coatings revealed that both CNx coatings had better anticoagulant properties and lower platelet adhesion than DLC. Compared with CN0.1〉 the CN0.22 coating showed longer dynamic clotting time （about 42 min）, static clotting time （23.6 min） and recalcification time （45.6 s）, as well as lower platelet adhesion （102 cells μm-2）, aggregation, and activation. The presence of nitrogen in the CNx coatings in- duced their enhanced hemocompatibility compared with DLC.