BACKGROUND: Apatite-wollastonite containing glass-ceramic (AWGC) is a kind of good bone repairing materials with excellent bioactivity, which is prepared by traditional melting process.OBJECTIVE: To observe AWGC prepared with sol-gel method and its bioactivity.DESIGN: Design experiment of materials process and in vitro bioactivity experiment.SETTING: College of materials science and Engineering of Sichuan University.MATERIALS: AWGC.METHODS: This experiment was conducted at the laboratory of College of Materials Science and Engineering of Sichuan University between August 2002 and May 2003. AWGC was prepared from sol-gel and followed by heattreating process. Bioactivity was investigated in vitro by immersing in the simulate body fluid (SBF) at 37 ℃ for 7 days . JL-1155 laser particle analyzer, X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscope were used for micro-morphological structure analysis.MAIN OUTCOME MEASURES: ①The crystalline structure and microstructure of sol-gel derived glass-ceramic② The apatite forming process in simulate body fluid③ The diameter of the pore of the sol-gel derived apatite/wollastonite glass-ceramicRESULTS: ①Main crystalline phases of the sol-gel derived glass-ceramic materials were hydroxyapatite/fluoroapatite [Ca10(PO4)6(OH, F)] and β-wollastonite[β-CaSiO3]; Microstructure contained many micro-pores of 2-3μ m;② Sol-gel derived AW glass ceramic had excellent bioactivity: plenty of apatite granules were generated on the surface of the material after soaking for 7 days. ③Porous scaffolds possessed good macro-porous structure with the interconnected macro pores of 300-400 μm in diameter;CONCLUSION: Apatite-wollastonite containing glass-ceramic (AWGC)with excellent bioactivity was developed by sol-gel process. The material is expected to be a good candidate for bone-repairing and bone tissue engineering scaffold materials.

It has been suggested that HCN1 is primarily expressed in hippocampus, however little is known about its effects on spatial learning and memory. In the present study, we investigated the effects of non-specific HCN1 blocker CsCl on spatial learning and memory by using Morris water maze and in situ hybridization in mice. The results showed CsCl 160 mg/kg ip for 4 days, and the mean escape latency was 34 s longer than that of normal control (P<0.01). In hippocampal tissues, staining for the HCN1 mRNA was stronger in the DG and CA1 region of the hippocampus (P <0.05, P<0.05, when CsCl-administration group was compared with normal group). Our results suggested that CsCl could significantly affect the spatial learning and memory in mice, and HCN channel is involved in the process of learning and memory.

This is a retrospective study of 103 cases of early gastric cancer undergoing surgery during the years of 1974-1988 with a special discussion on surgical treatment.The lesions were localized to the mu-cosal layer in 54.3%,to submucosal layer in 45.7%,In 10% of patients there was lymphnode metastasis,all of them were in the first station.Operation consisted of radical subtotal gastrectomy in 94.2%.and total gastrectomy in 5.8%.The extent of lymphatic excision was:Ro in 12.6%,R1 in 61.2% and R2 in 26.2% Postoperative chemotherapy was given in 61.2%.However no statistical difference of 5 years survival rate was found in respect to the extent of lymphatic excision as well as postoperative chemotherapy.Since 60.2% of EGC lesions were of minute,multiple and plane type,preoperattve en-doscopy and intraoperative biopsy of gastric mucosa,if necessary,should be carefully done to ascertain that no lesion was overlooked in the remnant of the stomach.Follow-up rate was 96%,and the survival rates of 3 and 5 years were 97% and 93.7%.This makes the authors believe that a radical operation of R1 is justified and routine postoperative chemotherapy is unnecessary.

In this communication, the values of serum CA-50 in a series of patients with benign and malignant GI diseases are reported. It was found that CA-50 was positive in 86.7% of 30 pancreatic cancer patients with an average level of 427.53U/ml, which was statistically different from that found in non-malignant control group. In this series serum CA-50 determination helped to confirm the diagnosis of pancreatic cancer in 6 cases, in which B-mode ultrasono-graphy failed to make a definite diagnosis, and in another 3 cases CT scanning was unable to disclose the tumor. The combination of CA-50, B-mode ultrasonography, and CT made definite diagnosis in 100% of all 30 pancreatic cancer patients. The author discussed the significance of CA-50 determination in the diagnosis and differential diagnosis of pancreatic cancer.

Studies on bioactive glass and glass-ceramic are important research high-lights in the field of biomedical materials. Due to their bioactivity, these materials can form a tight chemical bond with the living bone, when implanted. As a preeminent kind of these materials, A-W(Apatite/Wollastonite) bioactive glass ceramic has not only the excellent bioactivity and biocompatibility, but also the eminent mechanical properties, so it has been largely applied and developed in clinical practice. The development, preparation, properties, applications and the mechanism of its bond with bone are introduced in this paper. We will also put forward the prospect of the research and development of A-W bioactive glass ceramic.
Apatites ; chemistry ; Bone Substitutes ; chemistry ; Calcium Compounds ; chemistry ; Ceramics ; chemistry ; Mechanics ; Research ; Silicates ; chemistry ; Surface Properties

During the preparation of functional gradient materials (FGM) with plasma immersion ion implantation-ion beam enhanced deposition (PIII-IBED), the combination strength between the coating and the substrate would be greatly affected by the implantation dose and the distribution of implanted ions in substrate. According to the requirements of FGM, an idea of multi grades energy implantation had been suggested, with which the Gauss peak could be moved toward the surface, and the concentration of implanted ions could be maximized at the surface. In this study, the distribution of carbon ions implanted into titanic alloy substrate have been simulated theoretically, and the tentative idea have been confirmed experimentally.
Alloys ; Carbon ; Coated Materials, Biocompatible ; chemical synthesis ; Computer Simulation ; Heart Valve Prosthesis ; Titanium

In order to investigate the protective effect of hypoxic preconditioning on the cerebral ischemia-reperfusion injury, the expression of Bcl-2 and Bax was detected by using immunohistochemical staining after 3 h cerebral ischemia followed by 1, 6, 12, 24 and 48 h reperfusion respectively in rats treated with or without hypoxic preconditioning before cerebral ischemia. In addition,the apoptosis of neural cells and the behavioral scores for neurological functions recovery were evaluated by TUNEL staining and "crawvling method", respectively. Compared with control group (cerebral ischemia-reperfusion without hypoxic preconditioning), the expression of Bcl-2 was significantly increased, but that of Bax decreased in the hypoxic preconditioning group (cerebral ischemiareperfusion with hypoxic preconditioning), both P＜0. 05. The pre-treatment with hypoxic preconditioning could reduce the apoptosis of neural cells and promote the neurological function recovery as compared to control group. It was suggested that hypoxic preconditioning may have protective effects on the cerebral ischemia-reperfusion injury by inhibiting the apoptosis of neural cells, increase the expression of Bcl-2 and decrease the expression of Bax.

In the present paper, adhesive test, morphology observation, classified counting and deformation index calculation of the platelets on seven DLC samples made by different processes were carried out after XPS analysis, respectively. Then the effects of carbon phase components on amounts and deformation index of the platelets adhered to the samples were investigated by using the analysis of T-type correlation degree in the grey system theory. It has been shown from results that the amounts and the deformation index of the platelets adhered to the DLC samples made by plasma source ion implantation-ion beam enhanced deposition (PSII-IBED) are obviously less than those of DLC samples made by plasma CVD. The correlation degrees (negative) between the DLC carbon phase and the amounts as well as the deformation index of platelets are much more than those of the other four carbon phase components; besides, larger correlation degrees (positive) only appear between the deformation index of platelets and the C-H carbon phase or C-O carbon phase. It has been indicated that: (1) the effect of DLC carbon phase on platelets adhesion is much greater than that of the other four carbon phase components, the key to improvement in the hemocompatibility of DLC is to increase the DLC carbon phase content; (2) it is necessary to restrain the form or decrease the C-H carbon phase content and C-O carbon phase content so as to control their promotive action on deformation of the platelets adhered to the surface of DLC; (3) using PSII-IBED process to prepare DLC is helpful to improving the hemocompatibility of DLC. These conclusions are essential for designing and improving the deposition process of DLC.
Biocompatible Materials ; Carbon ; chemistry ; Diamond ; chemistry ; Humans ; Male ; Materials Testing ; Models, Biological ; Platelet Adhesiveness

The correlations between surface energy parameters and carbon phase components in six diamond like carbon film (DLC) samples made in different ways and processing conditions were further investigated using the analysis of T-type correlation degree in the Grey system theory based on our earlier studies such as the determination of carbon phase and surface energy parameters, the analyses of carbon phase components, surface energy parameters and adhesive characteristic of platelets for DLC. The results showed: (1) as a whole critical surface tension has the closest relation with carbon phase components, chromatic dispersion branch of surface tension takes the second place, but for the other four parameters, the correlation is weak; (2) DLC phase has larger negative correlation (degrees -0.57, -0.33) with critical surface tension and chromatic dispersion branch of surface tension, while its correlation degrees with the other four parameters related to polarity are all positive values smaller than 0.20; (3) C-H phase and C-O phase have larger positive correlation (degrees 0.48, 0.25) with critical surface tension. We have come to three conclusions (1) DLC phase plays a dominant part in hemocompatibilioty of DLC by powerfully decreasing humidification and limitedly increasing polarity; (2) the energy mechanism of platelet deformation enhanced by C-H phase and C-O phase involves increasing the critical surface tension of DLC; (3) the hemocompatibility of DLC can be evaluated by using the critical surface tension as index and using the content of DLC phase and additional content limitation of C-H phase and C-O phase as standard. This study has provided a theoretical basis for evaluating the hemocompatibility of DLC based on surface properties.
Biocompatible Materials ; chemistry ; Carbon ; chemistry ; Diamond ; chemistry ; Humans ; Male ; Materials Testing ; Membranes, Artificial ; Models, Biological ; Platelet Adhesiveness ; drug effects ; Surface Properties

In this study, the diamond like carbon (DLC) samples made from different processes and processing conditions, were subjected to the test of platelet adhesion. The surface energy parameters such as surface tension, critical surface tension, interface tension, adhesive power, and polar branch and chromatic dispersion branch of surface tension based on determining balanced contact angle of ethanol, water and different ratios of ethanol/water solution on surfaces of the samples were calculated, respectively. Then the effects of these parameters on the amounts and deformation index of the platelets adhering to the samples were assessed by analyzing the T-type correlation degree in the Grey system. The results showed: (1) all degrees of correlation between surface energy parameters and adhesion amounts of platelet are positive, but for deformation index, the correlation degrees are negative except for critical surface tension; (2) the adhesion amounts of platelet increase with the rising polar branch of surface tension, while the deformation index increases with rising chromatic dispersion branch of surface tension; (3) Both adhesion amounts and deformation index of platelet are positively correlated with critical surface tension to a higher degrees; (4) the effects of polar branch of surface tension on adhesion amounts and deformation index of platelet keep pace with the surface tension, interface tension and adhesive power. Thus two important conclusions have been obtained: (1) the adhesive characteristic of platelets to the surface of DLC is closely related with the surface energy of DLC; the hemocompatibility of DLC is decided by the balance between the polarity of DLC surface and the limited humidifying water on the surface; there is a blood compatible range delimited by critical surface tension; (2) adhesion and deformation of platelets on surface of DLC have different energy mechanism: polar surface is advantageous to the adhesion, while the deformation is achieved with the aid of chromatic dispersion action stem from the surface.
Biocompatible Materials ; chemistry ; Carbon ; chemistry ; Diamond ; chemistry ; Humans ; Materials Testing ; Platelet Adhesiveness ; Surface Properties