The generation of the endothelial specific cdc42-deficient mice and the effect of cdc42 deletion on the angiogenesis and embryonic development / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>High microvascular permeability plays an essential role in pathological process of multiple diseases such as septic shock, acute lung injury and acute respiratory distress syndrome, and burns. Inhibiting hyperpermeability is significant for controlling these conditions. Cdc42, as a main member of the small Rho GTPase family, plays a critical role in controlling and regulating the endothelial junctional permeability. We aimed to generate and identify endothelial specific cdc42-deficient mice by the Cre/loxp recombination approach, for examination in an animal model of the contribution of the cdc42 gene in the microvascular barrier function.</p><p><b>METHODS</b>We crossed cdc42(Flox/Flox) mice with mice expressing endothelial cell-specific Cre recombinase, and the offspring with the genotype cdc42(Flox/+)Tie2Cre(+/-) were back-crossed with the cdc42(Flox/Flox) mice. The cdc42(Flox/Flox)Tie2Cre(+/-) mice in the F2 generation were the target mice. If the cdc42 deficient mice did not survive, we would observe the cdc42 deficient mice embryos, and compare them with wild-type mice embryos.</p><p><b>RESULTS</b>Cdc42(flox/+)Cre(+/-) mice were mated with the cdc42(Flox/Flox) mice and among the living offspring there were no cdc42(Flox/Flox)Cre(+/-) target mice. We found the endothelial special cdc42 deficient embryos at the E7.5-E16.5 stage. We observed that cdc42 deficient embryos were much smaller, had fewer vessels and were a little more swollen compared with the wild-type embryos.</p><p><b>CONCLUSIONS</b>Endothelial specific knockout of cdc42 caused embryonic lethality and the mice did not survive to birth. The target embryos were much smaller, had fewer vessels and were a little more swollen compared with the wild-type embryos. These results demonstrated that the cdc42 plays an important role in development of embryos and in development of microvessels as well as microvascular permeability.</p>

Role of the AdeABC efflux pump in carbapenems resistance of clinical isolates of Acinetobacter baumannii / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of AdeABC efflux pump in carbapenems resistance of Acinetobacter baumannii in light of the phenotype and genetype of the efflux pump.</p><p><b>METHODS</b>The phenotype of the efflux pump was detected in 138 clinical isolates of A.baumannii using the efflux pump inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP). The mRNA expression of pump-encoding gene adeB in the strains was detected using quantitative real-time RT-PCR.</p><p><b>RESULTS</b>Of the 138 strains, 28 showed positivities for AdeABC efflux pump identified by Mueller-Hinton Broth with CCCP. Of the 39 strains resistant to meropenem, 15 (38.4%) showed positive results in CCCP assay, a rate significantly higher than that among the 99 sensitive strains (13.1%, 13/99) (X(2)=12.477(b), P=0.01). The mRNA expression of efflux pump-encoding gene adeB was detected by real-time RT-PCR at a level of 0.899∓∓1.172 in meropenem-sensitive strains, significantly lower than the level of 21.101∓∓21.443 in meropenem-resistant strains (t=4.403, P=0.000).</p><p><b>CONCLUSIONS</b>Efflux plays a role in carbapenems resistance in the clinical isolates of A. baumannii. The AdeABC efflux pump may be an important factor in reducing carbapenems sensitivity in A. baumannii.</p>

Effect of toluene diisocyanate on reactive oxygen species production and permeability of human bronchial epithelial cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of toluene diisocyanate (TDI) on the production of reactive oxygen species (ROS) and the permeability of human bronchial epithelial (HBE) cells.</p><p><b>METHODS</b>TDI-human serum albumin (TDI-HSA) conjugate was prepared using a modified Son's method. MTT assay was used to assess HBE cell viability after exposure to different concentrations of TDI-HSA. The level of intracellular ROS of HBE cells was detected by flow cytometry with an oxidation-sensitive fluorescent probe 2',7'-dichlorofluorescein diacetate (DCFH-DA) uploading, and the permeability of cell monolayer was assessed by detecting the transepithelial electrical resistance (TEER).</p><p><b>RESULTS</b>The exposure to 120 µg/ml TDI-HSA did not obviously affect the cell viability. Compared with the control group, the intracellular fluorescent intensity increased significantly in the cells exposed to 20, 60, and 100 µg/ml TDI-HSA (P<0.05). The intracellular ROS production increased significantly after 100 µg/ml TDI-HSA treatment (P<0.05), but the increment in ROS production was significantly suppressed by pretreatment of the cells with N-acetylcysteine (NAC) (P<0.05), which also enhanced the TEER decreased by TDI-HSA treatment (P<0.05).</p><p><b>CONCLUSIONS</b>TDI enhances the permeability of HBE cell monolayer partially through a ROS-mediated pathway, suggesting the importance of oxidative stress in TDI-induced pulmonary diseases.</p>

The comparison between the vascular endothelial cells special cdc42-deficient heterozygous mice and the non-knockout mice on lung tissue pathological change and vasopermeability in acute lung injury / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the change of lung tissue and vasopermeability between the vascular endothelial cells special cdc42-deficient heterozygous mice and the non-knockout mice in acute lung injury.</p><p><b>METHODS</b>The mice with vascular endothelial cell-specific expression of cre recombinase were crossed with cdc42(flox/flox) mice. The cdc42(flox/+)Cre(+/-) F1 offspring mice were crossed back with cdc42(flox/flox) mice, resulting in the F2 generation mice with three genotypes, namely cdc42(flox/+)Cre(+/-), cdc42(flox/flox)Cre(-/-) and cdc42(flox/+)Cre(+/-). The heterozygous mice with cdc42(flox/+)Cre(+/-) genotype were selected as the model mice, with the other two genotype groups as the control. After intratracheal instillation of 2 mg/kg LPS to induce acute lung injury, the mice were sacrificed to examine the lung pathologies, lung wet/dry ratio and lung microvascular permeability.</p><p><b>RESULTS</b>The heterozygous mice with cdc42 gene knockout (cdc42(flox/+)Cre(+/-)) showed no significant differences from the two control groups in the lung pathological score, lung wet/dry ratio or the lung microvascular permeability coefficient.</p><p><b>CONCLUSION</b>There were no significant difference on lung tissue and vasopermeability between the vascular endothelial cells special cdc42-deficient heterozygous mice and the non-knockout mice.</p>

Hydrogen dioxide increases the expression of vascular endothelial growth factor in human bronchiolar epithelium cell via a PI3K-dependent pathway / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of hydrogen dioxide (H(2)O(2)) on the expression of vascular endothelial growth factor (VEGF) in human bronchiolar epithelial (HBE) cells.</p><p><b>METHODS</b>MTT assay was used to assess HBE cell viability after exposure to different concentrations of H(2)O(2). VEGF/beta-actin gene fragments were amplified simultaneously by RT-PCR from the total HBE cell RNA, and VEGF protein expression in the cells was detected using ELISA.</p><p><b>RESULTS</b>The exposure to 200 micromol/L H(2)O(2) did not obviously affected the cell viability. Compared with those in the control cell, VEGF165/beta-actin and VEGF189/beta-actin ratios were significantly increased in the cells after treatment with 50, 200, and 600 micromol/L H(2)O(2) (P<0.05). The protein expression of VEGF significantly increased after 50 micromol/L H(2)O(2) treatment (P<0.05), but significantly decreased with pretreatment with the PI3K inhibitor Ly294002 (P>0.05).</p><p><b>CONCLUSION</b>Oxidative stress increases the expression of VEGF via a PI3K-dependent pathway in human bronchiolar epithelial cells, which may play an important role in the onset and maintenance of chronic inflammation in asthma.</p>

Respiratory syncytial virus increases the expression and release of high mobility group Box-1 protein in the lung tissue of mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the expression and release of high mobility group Box-1 protein (HMGB1) in the lung tissue of mice with respiratory syncytial virus (RSV) infection.</p><p><b>METHODS</b>Eighteen mice were randomized into PBS control group, RSV group and RSV/ribavirin group. Seven days after RSV infection in the mice in the latter two groups, the bronchoalveolar lavage fluid (BALF) was collected for cell counting and classification, and the levels of IL-4, IFN-gamma and HMGB1 in the supernatants of the BALF were detected. The left lungs of the mice were harvested for pathological examination with HE staining, and the right lungs were taken for detecting the expression of HMGB1 by Western blotting.</p><p><b>RESULTS</b>RSV induced a TH1 inflammation in the lung tissue as shown by significantly increased IFN-gamma and decreased IL-4 levels in the BALF. The total BALF cells, neutrophils and macrophages in the RSV group were significantly higher than those in the control group (P<0.05), and the cell counts were significantly decreased by ribavirin treatment (P<0.05). HE staining showed neutrophil and lymphocyte infiltration in the lumen and submucous layer of the airway in RSV group. The level of HMGB1 in the BALF significantly increased in the RSV group as compared with that in the control group (P<0.05), but was lowered by ribavirin treatment (P<0.05). The expression of the HMGB1 in the lung tissue significantly increased in the RSV group in comparison with that in the control group (P<0.05), and was not significantly decreased by ribavirin treatment (P>0.05).</p><p><b>CONCLUSIONS</b>The increased expression and release of HMGB1 in the lung tissue of mice with RSV infection is probably involved in the development of RSV infection-related lung diseases.</p>

Risk factors of ventilator-associated pulmonary Candida infection and drug-resistant analysis / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the risk factors for pulmonary Candida infection in association with mechanical ventilation and analyze the drug resistance profile of the Candida species that cause the infection.</p><p><b>METHODS</b>A retrospective analysis was conducted 114 patients receiving mechanical ventilation for over 48 h. According to the presence of pulmonary Candida infections, these patients were divided into infected group (n=50, 43.9%) and non-infected group (64 cases). Univariate analysis and multivariate logistic regression analysis were performed to identify the risk factors for the infection, and drug sensitivity test was carried out to evaluate the drug resistance of the Candida species.</p><p><b>RESULTS</b>Univariate analysis and multivariate logistic regression showed that the presence of at least two underlying diseases (OR=4.758, P=0.009), frequent changes of antibiotics (OR=6.128, P=0.001), and blood albumin below 25 g (OR=15.829, P=0.011) were the independent risk factors for pulmonary Candida infection associated with mechanical ventilation, and prophylactic antifungal treatment (OR=0.062, P=0.012) was a protective factor. Drug sensitivity test showed that Candida albicans was sensitive to most of the antifungal agents (100.0%), but the non-albicans Candida species were resistant to fluconazol (50.0%) and Itraconazole (38.5%).</p><p><b>CONCLUSION</b>Poor general conditions and frequent changes of antibiotics are the major risk factors for pulmonary Candida infection in patients receiving mechanical ventilation. Drug resistant analysis is helpful in the treatment of the infections.</p>

Causal analysis of initial misdiagnosis of pulmonary embolism / 南方医科大学学报

<p><b>OBJECTIVE</b>To analyze the causes of initial erroneous diagnosis of pulmonary embolism (PE) to improve the diagnostic efficiency.</p><p><b>METHODS</b>The clinical data of 63 patients with a definite diagnosis of PE were retrospectively analyzed. According to the initial diagnosis, the patients were divided into definite diagnosis group (Group A, 23 cases) and misdiagnosis group (group B, 40 cases). The risk factors, initial symptoms, time of definite diagnosis, Wells scores, revised Geneva scores, and findings in chest X-ray and ECGs after onset and before the definite diagnosis were compared between the two groups.</p><p><b>RESULTS</b>In group A, recent operations, malignancy, long-term bedridden state, PE history and deep vein thrombosis (DVT) symptom were more commonly seen than in group B, and the patients in group B were more likely to have hypertension, smoking, diabetes mellitus and lower limb varicose veins. The patients in group B had significantly lower Wells scores and revised Geneva scores than those in group A [2.50 (5.00) vs 6.00 (6.00), u=-3.296, P<0.001; 5.50 (4.75) vs 12.00 (9.00), u=-3.187, P<0.001, respectively]. In group B, chest examination in 22 of the 40 cases (55%) reported pulmonary infection, and among them, 15 were misdiagnosed as pneumonia. In groups A and B, SIQIIITIII/QIIITIII in ECG was found in 5 (21.7%) and 0 cases (0%), and normal ECG in 2 (8.7%) and 18 (45.0%) cases, respectively, showing significant difference between the two groups (P=0.010 and 0.003, respectively).</p><p><b>CONCLUSION</b>The initial misdiagnosis of PE results mainly from the low awareness of some of the PE risk factors on the part of the physicians, atypical clinical manifestations and excessive dependence on chest films and ECGs.</p>

Respiratory syncytial virus infection promotes the production of thymic stromal lymphopoietin and accelerates Th2 inflammation in mouse airway / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of respiratory syncytial virus (RSV) infection on the production of thymic stromal lymphopoietin (TSLP) and Th1/Th2 balance in asthmatic mice.</p><p><b>METHODS</b>Thirty-two female BALB/c mice were randomly divided into 4 groups, namely the PBS group, ovalbumin (OVA) group, RSV group and OVA/RSV group. The mice were sensitized by OVA and then stimulated with nebulized OVA, and RSV was inoculated into the nasal cavity of the mice. BUXCO noninvasive lung function detection was performed to examine the airway response to metacholine, and enzyme-linked immunosorbent assay (ELISA) was used to detect the serum levels of IL-4, IL-5, IL-13, and IFN-gamma in the mice. The cells in the bronchoalveolar lavage fluid (BALF) were counted and classified, and the supernatants of the BALF were used for the detection of TSLP. Histopathological changes in the lung tissues of the mice were examined using HE staining, and immunohistochemistry using anti-mouse TSLP antibody was performed to examine TSLP expressions in the airway epithelial cells.</p><p><b>RESULTS</b>RSV infection promoted the production of TSLP in the asthmatic mice, and the concentration of TSLP in OVA/RSV group (2.13-/+0.05 ng/ml) was significantly higher than that in the other groups (P<0.01). RSV infection increased the serum levels of IL-4, IL-5, IL-13, and IFN-gamma in the mice. The total BALF cells, eosinophils, lymphocytes and neutrophils in OVA/RSV group were significantly higher than those in the other groups; noninvasive lung function examination showed higher Penh value in OVA/RSV group (318.66-/+50.87) than in the other groups when the inhaled metacholine increased to 6.25 mg/ml (P<0.01). More obvious and extensive airway inflammatory cell infiltration in OVA/RSV group were observed, and immunohistochemical staining also showed higher expression of TSLP in the airway epithelial cells of OVA/RSV group.</p><p><b>CONCLUSIONS</b>RSV infection promotes the production of TSLP in the airway epithelial cells and increases the level of Th2 cytokines in asthmatic mice. Concurrent RSV infection can exacerbate Th2 inflammatory reaction in asthmatic mice.</p>

Toluene diisocyanate increases vascular endothelial growth factor expression in human bronchial epithelial cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of toluene diisocyanate (TDI) on the expression of vascular endothelial growth factor (VEGF) in human bronchial epithelial (HBE) cells.</p><p><b>METHODS</b>TDI-human serum albumin (TDI- HSA) conjugate was prepared using a modified Son's method. MTT assay was used to examine the viability of HBE135-E6E7 cells cultured in serum-free medium after treatment with HSA or TDI-HSA at different concentrations. VEGF mRNA expression of the HBE cells treated with HSA or TDI-HSA at 10, 20, 30 and 40 microg/ ml, respectively, was detected using semi-quantitative RT-PCR.</p><p><b>RESULTS</b>Treatment with 40 microg/ml HSA and 40 microg/ml TDI-HSA did not result in significant changes in the viability of HBE135-E6E7 cells. RT-PCR revealed the constitutive expression of two VEGF isoforms, namely VEGF189 and VEGF165, in cultured HBE135-E6E7 cells. After exposure to TDI-HSA at the different concentrations (except for 10 microg/ml), a significant increase occurred in both VEGF189 and VEGF165 mRNA expressions in HBE135-E6E7 cells as compared with the expressions in the control group and the HSA-treated cells (P<0.05), and significant dose dependence was noted in the effect of TDI-HSA (P<0.05). No significant difference was found in the expressions between the control cells and the HAS-treated cells (P>0.05).</p><p><b>CONCLUSION</b>TDI induces significant increase in VEGF expression in HBE cells, and VEGF overexpression may play an important role in the pathogenesis of TDI-induced asthma.</p>

Role of Smac in cisplatin-induced apoptosis of non-small cell lung cancer cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of Smac in cisplatin-induced apoptosis of non-small lung cancer cells in vitro.</p><p><b>METHODS</b>Non-small cell lung cancer A549 cells were incubated in the presence of cisplatin at different concentrations, and the cell proliferation status was observed using MTT assay. Flow cytometry was used for evaluation of the apoptosis of the incubated cells, and the expressions of Smac mRNA and protein were detected by RT-PCR and Western blotting, respectively.</p><p><b>RESULTS</b>Cisplatin inhibited the proliferation and induced apoptosis of A549 cells both in a concentration-dependent manner. Cisplatin also increased the expression of Smac at both the mRNA and protein levels, which was also concentration-dependent.</p><p><b>CONCLUSION</b>Increased Smac expression may play a critical role in cisplatin-induced apoptosis of the non-small cell lung cancer cells in vitro.</p>

Effect of N-acetylcysteine on HMGB1 and RAGE expression in the lungs of asthmatic mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the expression of HMGB1 and RAGE mRNA in the lungs of asthmatic mice and the effect of N-acetylcysteine (NAC) on their expression.</p><p><b>METHODS</b>Twenty-one female BALB/c mice were randomly divided into control group, asthma group and NAC group (n=7). The expressions of HMGB1 and RAGE mRNA and their distributions in the lungs were detected by RT-PCR and immunohistochemical method.</p><p><b>RESULTS</b>The expression levels of HMGB1 and RAGE mRNA were not significantly different between the control group (0.88-/+0.02 and 1.20-/+0.20, respectively) and the asthma model group (0.86-/+0.05 and 1.21-/+0.08, P>0.05). After NAC treatment, both of HMGB1 and RAGE mRNA levels (0.98-/+0.05 and 1.58-/+0.21) were significantly higher than those in the other two groups (P<0.05). HMGB1 was found in the nuclei and membrane of the bronchial and alveolar epithelial cells, and RAGE was located on the membrane of the alveolar epithelial cells.</p><p><b>CONCLUSION</b>HMGB1 and RAGE may play a role in the oxidative stress during asthma, but the exact mechanism needs further investigation.</p>

Influence of education level on self-evaluation and control of patients with bronchial asthma / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of education on self-evaluation and control level in patients with bronchial asthma.</p><p><b>METHODS</b>Seventy-five asthmatic patients with the initial diagnosis in line with the American Thoracic Society criteria, including 46 with junior high school education or below (group A) and 29 with senior high school education or above (group B), were asked to complete a survey to assess their symptoms and asthma attacks. Asthma control test (ACT) and peak expiratory flow rate (PEFR) evaluation were performed 8, 12 and 24 weeks after salmeterol/fluticasone therapy. Step-down treatment was administered according to GINA guidelines. The self-evaluation of the patients was assessed according to ACT score, physical signs and pulmonary function. An ACT score over 19 indicate well controlled condition. The effect of education on the self-evaluation and control level of bronchial asthma was assessed.</p><p><b>RESULTS</b>The two groups had similar basal level of pulmonary function (FEV1). Eight weeks after the therapy, 29 patients in group A had ACT score over 19, including 11 with high control level; in group B, 17 had ACT score over 19, of whom 4 showed high control level. There was no significant difference between the two groups in control levels and self-evaluation (P>0.05). At 12 weeks, 37 patients in group A had ACT score over 19, with 17 having high control level; 22 patients in group B had ACT score over 19, 4 showing high control level; the two groups were similar in the control levels (P>0.05) but showed significant difference in self-evaluation (P<0.05). At the time of 24 weeks, 42 and 26 patients had ACT score over 19 in the two groups, with 19 and 5 having high control level, respectively. The two groups differed significantly in the control levels (P<0.05) and self-evaluation (P<0.05).</p><p><b>CONCLUSION</b>The patients' education level may play a role in self-evaluation and control level of bronchial asthma, but its impact differs in the course of the treatment.</p>

Perindopril and losartan attenuate bleomycin A5-induced pulmonary fibrosis in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effects of angiotensin-converting enzyme inhibitor (ACEI) and angiotensin II type 1 receptor (AT-1 receptor) blocker on the progression of rat pulmonary fibrosis induced by bleomycin A5.</p><p><b>METHODS</b>Twenty-four male Wistar rats were randomized into pulmonary fibrosis model, perindopril treatment, losartan treatment and control groups. In the former 3 groups, pulmonary fibrosis was induced via intratracheal injection of bleomycin A5 (5 mg/kg), after which the rats in the perindopril and losartan groups received intragastric administration of the corresponding agents at the daily dose of 2 mg/kg and 10 m/kg, respectively. The rats in the control group had intratracheal injection of normal saline only. In the 4th week, the histological changes of the lung tissues were examined microscopically with Masson staining. Hydroxyproline content in the lungs was measured, and the protein expressions of AT-1 receptor, TGF-beta1 and IkappaBalpha were examined using Western blotting. DNA binding activity of NF-kappaB was analyzed with electrophoretic gel mobility shift assay (EMSA), and zymography was used to assess the activity of matrix metalloproteinase-2 and 9 (MMP-2, 9).</p><p><b>RESULTS</b>Both perindopril and losartan treatment significantly reduced the pulmonary fibrosis score, content of hydroxyproline, protein expression of TGF-beta1, DNA binding activity of NF-kappaB and MMP-2, 9 activity, and increased cytoplasmic protein expression of IkappaBalpha. Perindopril treatment lowered the protein level of AT-1 receptor.</p><p><b>CONCLUSION</b>Perindopril and losartan may inhibit bleomycin A5-induced pulmonary fibrosis in rats by reducing the protein expression of TGF-beta1 and suppressing the DNA binding activity of NF-kappaB and MMP-2, 9 activity.</p>

Construction of subtracted cDNA library by suppression subtractive hybridization for differentially expressed genes in eosinophils from asthma patients / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a subtracted cDNA library of differentially expressed genes in eosinophils from asthma patients.</p><p><b>METHODS</b>Suppression subtractive hybridization (SSH) was used to isolate the cDNA fragments of differentially expressed genes in the eosinophils of asthma patients before and after treatment. The cDNA fragments were directly inserted into T/A cloning vector to establish the subtractive library, followed by amplification of the library through E. coli transformation with calcium chloride and screening of blue and white clones of the transformants. One hundred positive bacterial clones were randomly picked and identified by colony PCR.</p><p><b>RESULTS</b>The amplified library contained more than 3,000 positive bacterial clones. Analysis of the randomly selected 100 white clones by PCR showed that 90% of the clones contained 100-500 bp inserts, which might be the cDNA fragments of differentially expressed genes in eosinophils of asthma patients before treatment.</p><p><b>CONCLUSION</b>A subtracted cDNA library of differentially expressed genes in the eosinophils of asthma patients before and after treatment is constructed successfully by SSH and T/A cloning techniques, which lays a solid foundation for screening and cloning new specific differentially.expressed genes in the eosinophils of asthma patients.</p>