Study on implant material of carbon/carbon composites / 生物医学工程学杂志

This study was aimed to evaluate the biocompatibility and mechanical property of carbon/carbon composites. At first, carbon/carbon composites were prepared by chemical vapor deposition, and the mechanical property of carbon/carbon composites was tested. The biocompatibility of carbon/carbon composites was evaluated by cytotoxicity test, sensitization test, micronucleus test and implantation test. Mechanical property test showed such carbon/carbon composites are of good compression property and tension property. Cytotoxicity test showed that the leaching liquor of samples has no effect on the growth and proliferation of L-929 cells. The medullary micronucleus frequency of mouse was 2.3 per thousand +/- 0.7 per thousand in experiment group. The sensitization test showed that the skin of the subjects of experiment group had slight erythema and edema, which was 0.188 +/- 0.40 according to Magnusson and Kligman classification. Implantation test revealed that there was slight inflammation around the tissue after the implantation of sample. At 12 weeks, scanning electron microscopy and histopathological exam indicated that the samples of experiment group were of good histocompatibility; and in comparison with control group, there was no significant differences (P > 0.05). So these kinds of samples have good biocompatibility, mechanical property and prospects of clinical application.

Study on biocompatibility of hydroxyapatite/high density polyethylene (HA/HDPE) nano-composites artificial ossicle / 生物医学工程学杂志

This study was aimed to evaluate the biocompatibility of Hydroxyapatite/High density polyethylene (HA/ HDPE) nano-composites artificial ossicle. The percentage of S-period cells were detected by flow cytometry after L929 cells being incubated with extraction of the HA/HDPE nano-composites; the titanium materials for clinical application served as the contrast. In addition, both materials were implanted in animals and the histopathological evaluations were conducted. There were no statistically significant differences between the two groups (P >0.05). The results demonstrated that the HA/HDPE nano-composite artificial ossicle made by our laboratory is of a good biocompatibility and clinical application outlook.

The expressions and clinical significance of tumor suppressor gene CX26 in laryngeal squamous cell carcinoma / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To investigate the expressions of tumor suppressor gene CX26 mRNA and coding protein in laryngeal squamous cell carcinoma, and to explore the relationship between CX26 gene and the biological behaviors of laryngeal squamous cell carcinoma for understanding the tumorigenicity and development of laryngeal squamous cell carcinoma.@*METHOD@#Laryngeal carcinoma tissues (studying group), which takeda from the center of tumors and laryngeal normal tissues (control group) takeda at the place of 1.0 cm out of the edge of the tumors, were took from 38 patients with laryngeal squamous cell carcinoma while they were in operation. Semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) was used to analyze the expression level of CX26 mRNA, and immunohistochemical staining (frozen section) was used to detect the expression of CX26 protein in laryngeal carcinoma tissues and laryngeal normal tissues of 38 cases, respectively.@*RESULT@#mRNA of CX26 gene was all positively expressed in laryngeal carcinoma tissues and laryngeal normal tissues of 38 cases by RT-PCR. However, CX26 mRNA was obviously down-regulated in laryngeal carcinoma tissues than that in laryngeal normal tissues (P < 0.05). Immunohistochemical staining showed CX26 protein was strong-positively expressed in laryngeal normal tissues in 34 cases (89.5%), while it was positively expressed in laryngeal carcinoma tissues in 18 cases (47.4%), and with the location alteration of CX26 protein in laryngeal carcinoma cells. There was significant difference between the expression rate of CX26 protein in laryngeal carcinoma tissues and in laryngeal normal tissues (P < 0.05). Meanwhile, the expression level of CX26 mRNA and the positive-expressed rate of CX26 protein of the laryngeal carcinoma tissues in the advanced stage patients group (III stage and IV stage) were significantly lower than these in the early stage patients group (I and II) (P < 0.05), and it was significantly lower in those who have a cervical lymph node metastasis than those without metastasis. (P < 0.05). Moreover, the expression level of CX26 mRNA and the positive-expressed rate of CX26 protein reduced along with the reduction of pathological differentiation, and there was significant difference among the well-differentiated group, moderately-differentiated group and poorly-differentiated group (P < 0.05).@*CONCLUSION@#CX26 gene may play an important role in the pathogenesis and development of laryngeal carcinoma and may be related to its prognosis.

Study on biocompatibility of MIM 316L stainless steel / 生物医学工程学杂志

This study was aimed to evaluate the biocompatibility of metal powder injection molding (MIM) 316L stainless steel. The percentage of S-period cells was detected by flow cytometry after L929 cells being incubated with extraction of MIM 316L stainless steel, and titanium implant materials for clinical application were used as control. In addition, both materials were implanted in animals and the histopathological evaluations were carried out. The statistical analyses show that there are no significant differences between the two groups (P > 0.05), which demonstrate that MIM 316L stainless steel has good biocompatibility.

Hydroxyapatite nanoparticles: a novel material of gene carrier / 生物医学工程学杂志

Hydroxyapatite nanoparticles were prepared in low Ca/P ratio by a kind of electrodeposition-hydrothermal process. The suspension of nanoparticles was cultured with SGC-7901 cells; metabolically active cells were evaluated by MTT analysis. Cells grew well and the nanoparticles in the concentration range of 10-100 microg/ml had no adverse effect on the cell viability. The results show that the nanoparticles have excellent biocompatibility with cells. Agrose gel electrophoresis analysis demonstrated that the nanoparticles had the potential to adsorb EGFP-N1 at the pH ranging between 2 to 7. Nanoparticle-DNA complex could transfer EGFP-N1 into the SGC-7901 cells, and the confocal microscopy analysis revealed that the cells with green fluorescence showed the efficiency of nanoparticle uptake to be about 80% of the efficiency of the Lipofectmine TM 2 000 uptake. In vivo, nanoparticles and DNA-nanoparticle complex were injected into mice respectively via tail-vein, and the mice grew well in two weeks. The liver, kidney, and brain of the mice were sampled and detected with electron microscopy, and all of these exhibited biodistribution of nanoparticles. This study demonstrates that Hydroxyapatite nanoparticles could be used as gene carriers.