[The preventive and therapeutic effect of advanced airway management on pulmonary infection in patients with inhalation injury after tracheotomy].

OBJECTIVE: To observe the preventive and therapeutic effect of advanced airway management on pulmonary infection in patients with inhalation injury after tracheotomy. METHODS: fourteen burn patients with inhalation injury admitted to our hospital from January 2001 to December 2004 were enrolled as control (C) group, and they were treated with conventional systemic therapy and management of airway. Twenty-seven burn patients with inhalation injury admitted to our hospital from January 2005 to October 2009 were enrolled as advanced (A) group, and they were treated with conventional systemic therapy and advanced airway management, including bedside isolation of airway, fixation of both oxygen supply tube and humidifying tube, humidification in specific body position, thinning of sputum, lavement of airway and procedural sputum elimination, steam inhalation combined with medicine, and suction of sputum with interrupted negative pressure. Result of bacterial culture of sputum (the 7th day after tracheotomy) and chest X-ray (at admission and the 7th day after tracheotomy), pulmonary infection, change in blood gas analysis index and oxygen saturation (SO(2)), (within 7 days after tracheotomy), and the number of patients curd in 2 groups were observed and compared. RESULTS: (1) Positive result of bacterial culture of sputum was observed in 11 (78.6%) patients in C group and 12 (44.4%) patients in A group. The difference between them was statistically significant (chi(2) = 4.36, P < 0.05). The main bacterium detected was Pseudomonas aeruginosa. (2) Pneumonia was suspected in 7 patients (25.9%) in A group by chest X-ray, which was obviously fewer than that in C group (8 Cases, 57.1%, chi(2) = 3.87, P < 0.05). The result was in accordance with the diagnosis of pulmonary infection. (3) No CO(2) retention, SO(2) and PaCO(2) abnormality caused by asphyxia was observed in 2 groups, PaCO(2) value in A group was close to that in C group (t = 0.89, P > 0.05). (4) In C group, 9 (64.3%) patients were cured, 5 patients died of pneumonia, wound sepsis, and MODS. In A group, 25 (92.6%) patients were cured, 2 patients died of MODS. Number of cure was obviously larger in A group than in C group (chi(2)= 5.22, P < 0.05). CONCLUSIONS: The advanced airway management has better effects on isolation and humidification of airway, and thinning, drainage, and elimination of sputum. And it can decrease the probability of blind suction and injury to airway, and it prevents pulmonary infection following tracheotomy.

In vitro maturation and migration of immature dendritic cells after chemokine receptor 7 transfection.

Dendritic cells are specialized antigen-presenting cells that regulate immunity and tolerance. Chemokine receptor 7 (CCR7), which is expressed by mature dendritic cells, mediates the migration of the cells to secondary lymphoid organs and thus regulates immune responses. It has been demonstrated that immature dendritic cells can induce immune tolerance, but they do not express CCR7 and cannot migrate to secondary lymphoid organs. We transfected immature dendritic cells with a recombinant adenovirus carrying the CCR7 gene to obtain immature dendritic cells with the ability to migrate. The maturity of the cells was monitored by scanning electron microscopy and flow cytometry. In addition, we assessed the ability of cells to migrate and the function of the cells using in vitro chemotactic and mixed leukocyte reaction assays. The results showed that immature dendritic cells became semi-mature, exhibiting a mild upregulation of co-stimulatory molecular expression and a few dendritic processes. Immunofluorescence assay and Western blotting indicated that CCR7 protein expression increased significantly in immature dendritic cells following CCR7 gene transfection. The in vitro chemotactic assay showed a significantly enhanced ability to migrate in response to CCL19 following CCR7 gene transfection. Moreover, transfected cells showed an enhanced ability to stimulate allogeneic T cell proliferation in vitro, but their ability was significantly weaker than that of mature dendritic cells. Interleukin-10 inhibited the differentiation and maturation of immature dendritic cells. It is concluded that, following CCR7 gene transfection, immature dendritic cells exhibit an enhanced ability to migrate and some of the characteristics of mature cells. Thus, these cells are of potential clinical significance in studies of immune tolerance induction during skin grafting after severe burns.

Construction of a full-length iASPP expression plasmid pcDNA3.1+/iASPP and its biological activity.

In order to obtain a full-length expression plasmid for the p53 inhibitor protein, iASPP, fractional amplification was used to clone its full-length coding sequence (CDS) region. The amplified PCR product was then digested and inserted into the pMD19-T simple vector and subcloned into the pCDNA3.1(+) vector. A recombinant eukaryotic expression vector containing the complete CDS region of iASPP was successfully constructed. pcDNA3.1(+)/iASPP was able to express iASPP protein in an in vitro translation system and in cells. Its biological activity was verified using Western blotting, immunoprecipitation and cell apoptosis analysis. This successful preparation of a full-length iASPP expression plasmid lays the foundations for further studies on the function of iASPP.

Effect of RNA interference of iASPP on the apoptosis in MCF-7 breast cancer cells.

ASPP family is proved to be apoptotic specific regulators of p53. Among them, iASPP acts as an inhibitor of p53. To investigate the effect of the iASPP RNAi on the apoptosis of breast cancer cell MCF-7, we transfected the recombinant plasmid PGCsilencer H1/Neo/GFP/RNAi into MCF-7. The iASPP expression was analyzed by RT-PCR and Western blot. The cell apoptosis was detected by FCM. The results show that the expression of iASPP is descended and the apoptosis rate is increased after transfection. Therefore, we conclude that inhibition of expression of iASPP may resume the ability of p53 to induce apoptosis in MCF-7 cells.

Downregulated mRNA expression of ASPP and the hypermethylation of the 5'-untranslated region in cancer cell lines retaining wild-type p53.

The p53 protein is one of the best-known tumour suppressors. Recently discovered ASPP1 and ASPP2 are specific activators of p53. To understand, if apoptosis-stimulating protein of p53 (ASPP) inactivation offers a selective advantage to tumors that have wild-type p53, we measured the mRNA expression of ASPP1 and ASPP2 in tumor cell lines retaining wide-type p53. In addition, the CpG island methylation status of ASPP1 gene and ASPP2 gene in the 5'-untranslated region was also investigated in order to understand the possible cause of abnormal expression of ASPP1 and ASPP2 in the tumor cell lines retaining wide-type p53. The data showed that mRNA expression of ASPP1 and ASPP2 is downregulated and CpG island tested is hypermethylated. These results indicated that ASPP CpG island aberrant methylation could be one molecular and genetic alteration in wild-type p53 tumours.