ABSTRACT
BACKGROUND:Low-temperature rapid prototyping technology is a new kind of rapid prototyping technology, and it is rapidly used in the preparation of bone tissue engineering scaffolds because it can make scaffold forming control able and can keep the biological activity of the materials, also can easily realize the scaffold with porous of three-dimensional structure and other advantages. OBJECTIVE:To investigate the preparation process of polyethylene glycol-modified polylactic acid-glycolic acid/nano-hydroxyapatite (PLGA-PEG/n-HA) using the low-temperature rapid prototyping, and to test its performance. METHODS:PLGA-PEG/n-HA and PLGA/n-HA were prepared by low-temperature rapid prototyping equipment. Under an electron microscopy, we observed ultra-structure of the scaffolds. Immersion (ethanol) method was used to test the porosity, and electronic testing machine was used to determine the material mechanical properties. Then these two kinds of scaffolds with rat osteoblasts were cultured in vitro, the cel adhesion rate was detected by precipitation method after 12 hours, and cel counting kit-8 method was used to determine the cel proliferation at culture days 1, 3, 5, 7, 9, 12. RESULTS AND CONCLUSION:Both of the two scaffolds had ideal aperture range and high porosity. But the aperture range of PLGA-PEG/n-HA scaffolds had large fluctuations, and the average aperture was smal er than that of PLGA/n-HA. Some pores were closed up. The cel adhesion rate and the cel growth curve of PLGA-PEG/n-HA was better than that of PLGA/n-HA (P<0.05), but the mechanical properties were less than PLGA/n-HA (P<0.05). The results showed the PLGA-PEG/n-HA scaffolds had good cel compatibility.
ABSTRACT
BACKGROUND:Nano-hydroxyapatite helps to improve the mechanical properties of bone implants. OBJECTIVE:To study the clinical effect of nano-hydroxyapatite artificial bone on col apsed fracture of the tibial plateau. METHODS:Fourteen cases of col apsed fracture of the tibial plateau combined with bone defects from March 2010 to September 2012 were analyzed retrospectively. The bone defect range was from 1.5 cm×1.0 cm to 3.1 cm×4.5 cm. Al patients were treated with nano-hydroxyapatite artificial bone at an implant amount of 5-14 g. Clinical and X-ray observations were applied at 1 week, 1 month and 3 months postoperatively. Hospital for Special Surgery scores were employed for recovery of knee function. RESULTS AND CONCLUSION:The patients were fol owed up for 12-27 months. Except for one case of a smal amount of wound exudates, no general side effects occurred in 13 cases. X-ray photo showed an integrity interface between nano-hydroxyapatite artificial bone and host bone at 3 months after treatment. Primary healing was obtained in al cases without any complications. Hospital for Special Surgery score was increased to (88.7±4.3) points at 1 year later. These findings indicate that the nano-hydroxyapatite artificial bone has a good biocompatibility and biomechanics, and it may be an ideal artificial bone for repairing col apsed fractures of the tibial plateau.
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Objective To explore the association among viral load,CD4 count and neutralizing ac-tivity of plasma from chronic HIV-1 infected former blood donors in Anhui province, China. Methods 294 chronically HIV-1 B' infected individuals from former blood donors in Anhni province were enrolled, whose plasma and peripheral blood mononuelnar cells (PBMC) were isolated. The viral load and CD4 were detec-ted, and the neutralization activity of plasma against primary virus (1597) and lab-adapted strain (SF33) was detected by Luciferase Assay System based on TZM cell line, and 50% neutralizing level was calculated by the Reed-Mueneh method. Results Neutralizing activity responding against SF33 strain was higher than 1597 (P<0.05). There was a positive correlation between neutralizing concentration of plasma against SF33 and viral load (1g) (r = 0.191, P = 0.001), but there was no correlation between neutralizing concen-tration of plasma against 1597 and viral load(lg) (r = 0.097, P = 0.096). Conchtsion In chronic HIV-1 infectious people, neutralizing level against SF33 increases with viral replication, however, there is no asso-ciation of plasma neutralizing against 1597 replication with viral load.
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Objective To develop methods of extracting DNA from malaria parasites on Giemsa-stained blood smears. Methods Improved Na2HPO4 method and Chelex-100 ion-exchange technique were used to extract DNA from Giemsa-stained or unstained blood smears. Nested PCR was employed for amplification and identification of allelotypes in the Plasmodium vivax merozoite surface protein-1(PvMSP-1). Results Target DNA bands appeared in all samples of unstained thick blood smears, while no DNA bands were visible in the fixed and stained thin smears. Both methods identified PvMSP-1 alleles from smears with parasitemia of ≥0.01%. Conclusion It is feasible to identify PvMSP-1 alleles from Giemsa-stained blood smear.