[Advances in the Application of Hydroxyapatite Composite Materials in Bone Tissue Engineering].

Hydroxyapatite (HAp) is the main inorganic component of the bones and teeth, and it possesses bioactivity and biocompatibility. However, due to its poor mechanical performance, slow degradation speed, and lack of diversity in its function, it is difficult to apply HAp alone as a scaffold material for bone tissue engineering. By combining HAp with other types of materials, composite materials with specific properties can be prepared, and the scopes of HAp applications can be expanded. Firstly, we elaborated on the importance, and strengths and weaknesses of HAp for bone tissue engineering biomaterials and then reviewed the research status of HAp composite materials used in bone regeneration. Secondly, about hot research topics in the field of applying HAp composite materials in bone repair, we summarized the representative findings in the field, and discussions and analysis were made accordingly. Finally, we also examined the future development prospects of HAp composite bone repair materials.

Preliminary screening and identification of stem cell-like sphere clones in a gallbladder cancer cell line GBC-SD.

This paper aims to screen and identify sphere clone cells with characteristics similar to cancer stem cells in human gallbladder cancer cell line GBC-SD. GBC-SD cells were cultured in a serum-free culture medium with different concentrations of the chemotherapeutic drug cisplatin for generating sphere clones. The mRNA expressions of stem cell-related genes CD133, OCT-4, Nanog, and drug resistance genes ABCG2 and MDR-1 in sphere clones were detected by quantitative real-time polymerase chain reaction (PCR). Stem cell markers were also analyzed by flow cytometry and immunofluorescent staining. Different amounts of sphere clones were injected into nude mice to test their abilities to form tumors. Sphere clones were formed in serum-free culture medium containing cisplatin (30 µmol/L). Flow cytometry results demonstrated that the sphere clones expressed high levels of stem cell markers CD133(+) (97.6%) and CD44(+) (77.9%) and low levels of CD24(+) (2.3%). These clones also overexpressed the drug resistance genes ABCG2 and MDR-1. Quantitative real-time PCR showed that sphere clones expressed stem cell genes Nanog and OCT-4 284 and 266 times, respectively, more than those in the original GBC-SD cells. Immunofluorescent staining showed that sphere clones overexpressed OCT-4, Nanog, and SOX-2, and low expressed MUC1 and vimentin. Tumor formation experiments showed that 1×10(3) sphere clone cells could induce much larger tumors in nude mice than 1×10(5) GBC-SD cells. In conclusion, sphere clones of gallbladder cancer with stem cell-like characteristics can be obtained using suspension cultures of GBC-SD cells in serum-free culture medium containing cisplatin.

Effect of Lidan Granule on bile lithogenesis in patients with choledocholithiasis combined with cholecystolithiasis.

OBJECTIVE: To observe the effect of Lidan Granule (, LDG) on bile lithogenic tendency and biliary 33.5 kd vesicular protein (VP) and to explore its mechanism. METHODS: Sixty patients with choledocholithiasis combined with cholecystolithiasis were randomly assigned to the LDG treated group, the sodium cholate treated group for positive control, and the untreated control group, 20 patients in each group. The 4 bile lithogenic trend indexes, including lithogenic index (LI), unconjugated bilirubin percent (UCB%), unconjugated bilirubin saturation index (BSI) and Z-value, were determined before and after treatment. The content of VP in bile was determined as well. RESULTS: Before treatment, the LI, UCB%, BSI and Z-value in the LDG treated group were 1.298+/- 0.265, 34.72+/-2.96, 0.353+/-0.093 and 0.556+/-0.499, respectively, which was decreased after the 2-week treatment to 0.926+/-0.208, 8.93+/-1.19, 0.154+/-0.056 and 0.257+/-0.211, respectively (all P<0.05). Meantime, the content of VP was also lowered from 0.050+/-0.005 g/L to 0.032+/-0.005 g/L. However, no significant change in any of the above-mentioned indexes was found in the other two groups. CONCLUSION: LDG could effectively suppress bile lithogenic trend and reduce 33.5 kd VP in bile.

Purification and characterization of 33.5 kDa vesicular protein in human bile.

AIM: The present study was undertaken to purify and partially characterize the 33.5-kilodalton (33.5 kDa) vesicular protein in human bile and to explore the possible molecular mechanisms of the initial crystal nucleation process. METHODS: The 33.5 kDa vesicular protein was isolated by ultracentrifugation and further purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under nonreducing conditions. The purified 33.5 kDa vesicular protein was subjected to N-terminal amino acid sequencing and amino acid analysis. Cholesterol crystallization activity was detected by cholesterol crystal growth assay. The sugar chain of the 33.5 kDa vesicular protein was analyzed by dot-immunobinding assay of lectin coupled to a peroxidase (HRP-DSA, HRP-ConA, HRP-WGA) and was deglycosylated using two different enzymatic approaches (N-deglycosylation and O-deglycosylation) to determine the molecular weight of the protein component, the type of linkage between polypeptide and carbohydrate components. RESULTS: The 33.5 kDa vesicular protein with complicated glycan was an extensively glycosylated (37.3%) monomer and these sugar chains strongly bound to DSA, but did not bind to ConA. Amino acid sequencing indicated that the protein was unique. The 33.5 kDa vesicular protein exhibited potent cholesterol crystallization promoting activity in vitro with derived crystal growth curve indices It, Ig, Ic presented as 0.57, 1.52, and 1.63 respectively. Both enzymatic proteolysis and N-deglycosylation of the protein removed all activity. CONCLUSION: These data suggest the 33.5 kDa vesicular protein may be responsible for the pathogenesis of cholesterol gallstone disease, and the sugar chains play an important role in pro-nucleating process.

[ELISA kit for detection of biliary vesicular protein and its preliminary clinical application].

OBJECTIVE: To establish a rapid and precise detective method of 33.5 kd vesicular protein and to screen an effective treatment of cholelithiasis. METHODS: Specific antibody of the biliary vesicular protein was obtained by immunizing rabbits and enzyme-linked immunosorbent assay (ELISA) kit was developed. The concentrations of 33.5 kd vesicular protein in serum and bile of gallstone patients and control were examined respectively. The effects of Cholagogue Dry Syrup and Eulektrol Capsule on decreasing 33.5 kd vesicular protein were also studied by ELISA kit. RESULTS: One-step ELISA equation was Y=0.035 X (r=0.99). The vesicular protein concentrations in serum and bile of cholesterol gallstone group [(179.8+/-97.9) mg/L and (213.4+/-70.1) mg/L respectively] were significantly (P<0.05) higher than in the pigment stone group and control. Data showed that, with 2-week administration, Cholagogue Dry Syrup significantly decreased both biliary and serum 33.5 kd vesicular protein of cholesterol gallstone patients, while Eulekrol Capsule and control groups didn't have the same results. CONCLUSION: The concentrations of 33.5 kd protein are different in cholesterol gallstone patients and healthy groups which might be related to cholesterol nucleation process. Cholagogue Dry Syrup is of cholagogic and litholytic effect by decreasing biliary lithogenesis.