Current bioprosthetic heart valves implanted with viable human cells can be categorized into two basic designs, tissue engineering heart valve and porcine aortic valve implanted with viable human cells. Tissue engineering heart valve is constructed by seeding a synthetic polyglycolic acid fiber based biodegradable scaffold with viable human autologous cells. The fibroblasts are first seeded on valve scaffold. When the fibroblasts reached confluence, endothelial cells are seeded onto the surface of leaflets and grown into a single monolayer. Porcine aortic valve implanted with viable human cells is generated by removing native cells from tissue and then repopulating the tissue with viable human autologous cells. The method of removing native cells from fresh porcine aortic valve comprises subjecting the valve tissue to a hypotonic/hypertonic treatment, then treating the valve tissue with an enzyme-based solution. Isolated cell lines are cultured and thereafter such a valve matrix is implanted with fibroblasts, followed by endothelial cells. Bioprosthetic heart valves implanted with viable human cells do not produce and adverse immune response by the recipient upon implant, and possesses the regenerative capabilities.

Objective To investigate the influence of blood arsenic concentration change on hepatic and renal function of rats administered with different toxic dosages of realgar by applying the linear mixed-effects model.Methods SD rats were given gastric gavage of realgar at the single dose of 3.738g/kg,1.869 g/kg and 0.935 g/kg respectively.After administration,the concentration of blood arsenic,the activities of urine alkaline phosphatase(AKP),N-acetyl-beta-D-glucosaminidase(NAG),serum glutamic oxaloacetic transaminase(GOT) and glutamate-pyruvate transaminase(GPT) activities,serum creatinine(Cr) level,and blood urea nitrogen(BUN) content were detected in different groups at different time points.The detection results were analyzed with the linear mixed-effects model.Results The changes of urine AKP and NAG activities,serum BUN content and serum GOT activity were presented in a dose-dependent manner,and had linear correlation with arsenic concentration.Conclusion In the dose range of 0.935 to 3.738 g/kg,realgar can cause the hepatic damage and the injury of tubular epithelial cells of kidney,but has not affected the renal excretion.

Objective To investigate the impact of photodynamic therapy (PDT) with verteporfin on the expression of pigment epithelial derivative factor (PEDF) mRNA and vascular endothelial growth factor (VEGF) mRNA in adult retinal pigment epithelial (RPE) cells in vitro. Methods The changes of cellular viability before and after PDT were assessed by methyl thiazolyl tetrazolum (MTT) colorimetric assay. Semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) was conducted to detect the expression of PEDF and VEGF mRNA in RPE cells before and after PDT. Results PDT caused the death of RPE cells. The cellular mortality was positively correlated with the power of photocoagulation and the concentration of verteporfin. Conclusion PDT could down-regulate the expression of PEDF and VEGF mRNA in adult RPE cells in vitro, which may relate to the cure or relapse of subfoveal choroidal neovascular membrane after PDT.

Objective To study the causes, diagnosis and treatment of the spontaneous perforation of sigmoid colon(SPSC). Methods The clinical data of 11 patients with SPSC admitted into our hospital from January. 1984 to September. 2000 were analyzed retrospectively. Results All the 11 cases of SPSC were proved by operation. Among them, 4 cases had chronic constipation history, 1 case complicated with mild proctoptoma before operation and the other 6 cases had no special records. 9 cases were misdiagnosed as perforation of acute appendicitis, perforation of upper gastroenteric tract, perforation of colon carcinoma, inflammatory perforation or fecal mass perforation. 2 cases recovered after repairing operation; of 9 cases underwent colostomy and other procedure, 7 cases recovered and colostomy closure was done 2-3 months after operation. 2 cases died after operation. Conclusions The occurrence of SPSC is closely related to the configuration and position of the patient's sigmoid colon. Increase of intra-abdominal pressure and intra-intestinal pressure are the predisposing causes of the disease. This disease has no special clinical manifestation. The key to diagnosis is a full knwledge of the disease before operation. The main treatment is operation. The mode of operation is determined according to patient's age, general condition, severity of abdominal pollution, attacking time. The best mode of operation is to repair and close the perforation or to resect and anastomose the bowel and colostomy.

Aim To investigate the release feature of ginsenoside Rd solid lipid nanoparticles (Rd-SLN) in vitro,and to clarify the difference in absorption of Rd-SLN from varied rat intestinal segments and pharmacokinetic properties in vivo. Methods Dialysis method was used to determine ginsenoside Rd release rate from nanoparticles in vitro. Perfusion method was used to study the intestinal absorption of Rd-SLN in rat. HPLC assay was established to determine the concentration of ginsenoside Rd in plasma. After intragastric administration,the concentrations of drug in rat blood at different time points were recorded to investigate the absorption and pharmacokinetics of Rd-SLN. Results The release of ginsenoside Rd from Rd-SLN was slowed down and presented the property of sustained release. There was no significant difference between the absorption rate of Rd-SLN and control solution in duodenum and jejunum. However,it was obviously different in ileum and colon. Comparing with other intestinal segments,significantly higher percentage of Rd-SLN was absorbed in colon. In Rd-SLN group,the concentration of ginsenoside Rd in blood was maintained,and the Cmax,MRT,AUMC,and AUC were all increased. Conclusions Rd-SLN possesses sustained-release effect. The colon is the preferable absorption site for Rd-SLN in intestinal tract. Rd-SLN can enhance the oral bioavailability of ginsenoside Rd.

Objective To investigate the prevalence of virulence genes(ply, pspA, nanA, lytA, psaA) among Streptococcus pneumoniae recently isolated from clinical patients. Methods The 133 strains were isolated from patients in three teaching hospitals in Chongqing from 2006 to 2008. Polymerase chain reaction was used to screen for virulence genes (ply, pspA, nanA, lytA, psaA). Results The positive rate of lytA, psaA, ply, nanA and pspA in 133 clinical isolates were 94.7%, 85.0%, 82.7%, 84. 2% and 60.2%, respectively. The positive rates of the lytA, psaA, ply, nanA and pspA genes in 87 common serotypes isolates was 100%, 87.4%, 86.2%, 89.7%, 67.8%, respectively. Conclusion The total positive rates of five virulence genes in the 133 clinical strains were high. The positive rates of five genes in the com-mon serotypes isolates were higher than those in the no-common serotypes. These genes are important virulence genes of Streptococcus pneumoniae. They could be candidates for protein vaccine of Streptococcus pneumoniae.

Objective To explore the relationship between high-risk human papillomavirus (HPV) DNA and biological behavior of cervical carcinoma. Methods Sixty-six patients of cervical carcinoma with cytological examinations and 103 patients of cervical carcinoma followed-up after surgical operation were selected for high-risk HPV DNA test with second-generation hybrid capture technique (HC2 Ⅱ). Results ①HPV DNA was positive in 62 and negative in four of 66 patients of cervical carcinoma with an overall prevalence of 94%. ②There was no significant difference in positive HPV DNA of patients with cervical carcinoma between their varied clinical stages and pathologic grades. But, HPV positivity and HPV DNA load in patients with myometrial invasion were higher than those in patients without invasion (P < 0. 05).③ HPV DNA conversed to negative in 99 of 103 patients (96%) with cervical carcinoma after surgical operation from positivity before operation. Conclusions High-risk HPV infection may correlate with angiogenesis, invasion and metastasis of cervical carcinoma and HC2 Ⅱ can be used as an effective method to detect HPV DNA.

Objective To explore the surgical treatments through anterior and posterior approaches for anterior and posterior compression of cervical spinal cord. Methods The clinical data of 25 cases of anterior and posterior compression of cervical spinal cord from June 1999 to November 2003 were summarized retrospectively. There were 18 males and seven females with age range of 28-56 years (average 36.4 years). Of all,18 cases were with tricolumnae fractures of cervical spine caused by traffic injury,five with cervical herniation and two with malignant macrophage tumor in vertebral body and annex and vertebral lamina. Results All 25 cases underwent internal fixation decompression with I-stage combination operation of anterior and posterior approaches. Of 18 cases with tricolumnae fractures,one died and 17 recovered in various degrees. In five cases with cervical herniation,the positive sign disappeared basically. Two cases of malignant giant-cell tumor appeared metastatic carcinoma in the lungs 10 months after operation. Conclusions The I-stage combination operation of anterior and posterior approaches is an ideal way for the patients suffering from anteropsterospinal compression in cervical spinal cord. It can not only decompress completely the cervical spinal cord,stabilize the wounded cervical vertebra,but also facilitate nursing and function training and be beneficial to the recovery of spinal cord function.

BACKGROUND: With the rapid development of tissue engineering, a single biological scaffold material is hard to meet the needs of tissue engineering. Therefore, composite scaffolds with excellent performance will be obtained by combining two or more kinds of materials.OBJECTIVE: To detect the adherence and proliferation of dental pulp stem cells on the Chitosan-fibrin composite scaffold.METHODS: Dental pulp stem cells were isolated and extracted from C57 neonatal rats through modified enzyme-digestion method, and subcultured to the third generation, followed by adipogenic and osteogenic induction in vitro. Then, induced cells were identified. The chitosan-fibrinogen composite scaffold was prepared, and the pore size and porosity were determined. The chitosan-fibrin composite scaffold was co-cultured with passage 3 dental pulp stem cells to observe the cell proliferation by MTT assay, and the morphology of the composite scaffold, cell adhesion,proliferation and extracellular matrix secretion were observed under scanning electron microscope. In addition, the cells were inoculated directly on the bottom of culture plate as controls.RESULTS AND CONCLUSION: The dental pulp stem cells were successfully isolated and cultivated, and positive for osteogenic and adipogenic differentiation. The pore size and porosity of the composite scaffold was (105.32±22.10) μm and (87.714±1.276)%, respectively. The S-shaped proliferation curve in the experimental group was similar with that in the control group; the proliferation rate in the experimental group was significantly higher than that in the control group after 4-8 days of culture (P < 0.05). At the 2nd day after co-culture, the cells adhered tightly and grew well onto the composite scaffold; at the 4th day, enlarged cells began to proliferate obviously with abundant extracellular matrix; the surface and pores of the scaffold were full of cells at the 6th day. These results indicate that the chitosan-fibrin composite scaffold is suitable for the adhesion and proliferation of dental pulp stem cells.

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