β-lactam antibiotics interfere with cross-linking of the bacterial cell wall, but the killing mechanism of this important class of antibiotics is not fully understood. Serendipitously we found that sub-lethal doses of β-lactams rescue growth and prevent spontaneous lysis of Staphylococcus aureus mutants lacking the widely conserved chaperone ClpX, and we reasoned that a better understanding of the clpX phenotypes could provide novel insights into the downstream effects of β-lactam binding to the PBP targets. Super-resolution imaging revealed that clpX cells display aberrant septum synthesis, and initiate daughter cell separation prior to septum completion at 30°C, but not at 37°C, demonstrating that ClpX becomes critical for coordinating the S. aureus cell cycle as the temperature decreases. FtsZ localization and dynamics were not affected in the absence of ClpX, suggesting that ClpX affects septum formation and autolytic activation downstream of Z-ring formation. Interestingly, oxacillin antagonized the septum progression defects of clpX cells and prevented lysis of prematurely splitting clpX cells. Strikingly, inhibitors of wall teichoic acid (WTA) biosynthesis that work synergistically with β-lactams to kill MRSA synthesis also rescued growth of the clpX mutant, as did genetic inactivation of the gene encoding the septal autolysin, Sle1. Taken together, our data support a model in which Sle1 causes premature splitting and lysis of clpX daughter cells unless Sle1-dependent lysis is antagonized by β-lactams or by inhibiting an early step in WTA biosynthesis. The finding that β-lactams and inhibitors of WTA biosynthesis specifically prevent lysis of a mutant with dysregulated autolytic activity lends support to the idea that PBPs and WTA biosynthesis play an important role in coordinating cell division with autolytic splitting of daughter cells, and that β-lactams do not kill S. aureus simply by weakening the cell wall.
Objective
To evaluate whether the level of serum vascular endothelial growth factor(VEGF)and platelet-derived growth factor(PDGF-BB)correlates with the glucose fluctuation and microangiopathy, and to explore the mechanism of interaction in type 2 diabetic patients with normal glycosylated hemoglobin values.
Methods
A total of 100 type 2 diabetic patients with HbA1c less than 7% treated in the Heilongjiang Province Hospital were enrolled in the study with 52 males and 48 famales, aged 40-66 years old. According to the existing diabetic microangiopathy, the subjects were divided into the following three groups: the T2DM group without documented microangiopathy (n=30, 14 males and 16 females, aged (50±11) years old); the diabetic nephropathy (DN) group (n=38, 20 males and 18 females, aged (52±10) years old); the diabetic retinopathy (DR) group (n=32, 18 males and 14 females, aged (53±13) years old). The healthy control group consisted of 25 subjects with 12 males and 13 famales aged (48±9) years old, who carried out routine health examination in the same hospital during the same enrollment period. All the patients went through the laboratory examination and the following parameters were taken: fasting plasma glucose (FPG), total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein (HDL-C), 2 h postprandial plasma glucose (2 h PG), 24 h urine albumin (24 h urine ALB) and glycosylated hemoglobin (HbA1c). The continuous glucose monitoring system was used to detect mean blood glucose(MBG), standard deviation of mean blood glucose(SDBG), mean amplitude of glucose excursions(MAGE), largest amplitude of glucose excursions(LAGE), absolute means of daily differences (MODD) and area under curve (AUC). The level of serum VEGF and PDGF-BB were measured by the enzyme-linked immunosorbent assay (ELISA). SPSS 19.0 was used for the statistical analysis with the data shown as (±s). The t test, was used to compare difference between the groups and the single factor analysis of variance was used to investigate the correlation among the groups. The logistic regression analysis was used to explore the correlation factors for the diabetic microvascular complications, while the multiple linear regression analysis was adopted to investigate the correlation factors for the level of VEGF and PDGF-BB, Statistical difference was accepted at P<0.05.
Results
The level of PDGF-BB was significantly increased in the DN group than that of the T2DM group without documented microangiopathy and the normal control group ((53±12), (31±6), (26±4) μg/ml, respectively with F=9.56 and P<0.05). The level of VEGF was significantly increased in the DR group than that of the T2DM group without documented microangiopathy and the normal control group ((217±57), (105±12), (74±10)μg/ml, respectively with F=8.13 and P<0.05). Compared with the T2DM group without documented microangiopathy, the DN group showed significantly higher SDBG, MAGE, LAGE, MODD and AUC ((2.41±0.34), (7.9±0.4), (8.1±0.4), (2.51±0.3), (8.0±0.7)mmol/L, respectively with t=2.57, 3.46, 5.75, 3.59, 4.28 and P<0.05), while the DR group showed significantly higher SDBG, MAGE, LAGE, MODD and AUC((2.4±1.7), (7.9±0.4), (8.1±0.4), (3.1±1.6), (8.2±0.6)mmol /L, respectively with t=3.29, 3.77, 5.38, 4.54, 3.16 and P<0.05). The level of PDGF-BB, VEGF and the blood glucose fluctuation were the independent risk factors for the diabetic microangiopathy revealed by the logistic regression analysis. Taken the level of PDGF-BB and VEGF as the dependent variables, and the blood glucose fluctuation index of SDBG, LAGF, MAGE, MODD, AUC and 2 h PG as the independent variables, the multiple linear regression analysis showed the greatest impact of MAGE, SDBG and 2 h PG on the level of PDGF-BB and VEGF.
Conclusion
Blood glucose fluctuation significantly correlates with the development and progression of the microangiopathy in type 2 diabetics. The level of VEGF and PDGF-BB could be increased by the blood glucose fluctuation, which may involve in the in the progression of the diabetic retinopathy and nephropathy.
Key words:
Diabetes mellitus, type 2; Microangiopathy; Continuous blood glucose monitoring; Vascular endothelial growth factor; Platelet-derived growth factor
Objective To observe the drug resistance at different stages of Candida(C.) albicans biofilm formation.Methods To form the biofilm in glass slide,then observe the biofilm morphology by inverted microscope at different development stages(2,4,8,24,48 hours).Using National Committee for Clinical Laboratory Standards(NCCLs) microdilution to detect drug resistance of dissociative C.albicans and 2,3 bis(2methoxy 4 nitro 5 sulfophenyl) 5(phenylamino) carbonyl 2H tetrazolium hydroxide(XTT) reduction method to test the change of C.albicans drug resistance in biofilm.Results Antifungal resistance of biofilm-grown cells increased as the biofilm maturation.Compared with dissociative C.albicans strains,the drug resistance was stronger more than 100 times.Conclusion There is positive correlation between drug resistance and biofilm maturation of C.albicans.
Human enterovirus 71 (HEV71) has emerged as the leading cause of viral encephalitis in children in most Asian countries. The roles of host miRNAs in the neurological pathogenesis of HEV71 infection remain unknown. In the present study, comprehensive miRNA expression profiling in HEV71-infected human neuroblastoma SH-SY5Y cells was performed using the Affymetrix Gene Chip microarray assay and was validated using real-time RT-PCR. Among the 69 differentially expressed miRNAs, miR-1246 was specifically induced by HEV71 infection in human neuroblastoma cells, but inhibition of miR-1246 failed to affect HEV71 replication. Parallel mRNA and microRNA profiling based on the 35 K Human Genome Array identified 182 differentially regulated genes. Target prediction of miR-1246 and network modeling revealed 14 potential target genes involved in cell death and cell signaling. Finally, a combined analysis of the results from mRNA profiling and miR-1246 target predication led to the identification of disc-large homolog 3 (DLG3), which is associated with neurological disorders, for further validation. Sequence alignment and luciferase reporter assay showed that miR-1246 directly bound with the 3′-UTR of DLG3 gene. Down-regulation of miR-1246 induced significant changes in DLG3 expression levels in HEV71-infected SHSY5Y cells. Together, these results suggested that miR-1246 might play a role in neurological pathogenesis of HEV71 by regulating DLG3 gene in infected cells. These findings provide new information on the miRNA and mRNA profiles of HEV71-infected neuroblastoma cells. The biological significance of miR-1246 and DLG3 during the course of HEV71 infection deserves further investigation.
Purpose To study whole-brain microstructural alterations in patients with end-stage renal disease (ESRD) and examine the relationship between brain microstructure and physiological indictors in the disease. Materials and Methods Diffusion tensor imaging data were collected from 35 patients with ESRD (28 men, 18–61 years) and 40 age- and gender-matched healthy controls (HCs, 32 men, 22–58 years). A voxel-wise analysis was then used to identify microstructural alterations over the whole brain in the ESRD patients compared with the HCs. Multiple biochemical measures of renal metabolin, vascular risk factors, general cognitive ability and dialysis duration were correlated with microstructural integrity for the patients. Results Compared to the HCs, the ESRD patients exhibited disrupted microstructural integrity in not only white matter (WM) but also gray matter (GM) regions, as characterized by decreased fractional anisotropy (FA) and increased mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). Further correlation analyses revealed that the in MD, AD and RD values showed significantly positive correlations with the blood urea nitrogen in the left superior temporal gyrus and significantly negative correlations with the calcium levels in the left superior frontal gyrus (orbital part) in the patients. Conclusion Our findings suggest that ESRD is associated with widespread diffusion abnormalities in both WM and GM regions in the brain, and microstructural integrity of several GM regions are related to biochemical alterations in the disease.
To investigate the Toxoplasma gondii infection status in pregnant women with history of adverse pregnancy and risk factors in Bazhou area, Hebei Province.A total of 302 pregnant women with the history of adverse pregnancy were chosen as respondents (an experimental group) in the hospital from March 2012 to December 2015, and 197 pregnant women without the history of adverse pregnancy as a control group. TOX-IgG and TOX-IgM were detected by using ELISA in two groups. The risk factors of Toxoplasma infection were surveyed by questionnaires.The total positive rate of Toxoplasma antibodies was 28.15% (85/302) in the experimental group, which was significantly higher than that [9.64%(19/197)] in the control group, and the difference was statistically significant (χ2 = 24.76, P＜0.05). The positive rates of TOX-IgM, TOX-IgG and TOX-IgM + TOX-IgG were 6.95% (21/302), 18.54% (56/302), and 2.65% (8/302) respectively in the experimental group, which were higher than 2.03% (4/197), 7.61% (15/197), and 0% (0/197) respectively in the control group (χ2 = 6.07, 11.67, 3.76, all P＜0.05). The questionnaire survey showed that the proportions of keeping pets, cutting board regardless, liking to eat hot pot or barbecue, eating raw meat, often eating in the restaurant in the pregnant women with Toxoplasma infection were higher than those in the pregnant women without Toxoplasma infection, and the differences were statistically significant (χ2 = 22.57, 3.96, 5.87, 7.40, 4.86, all P＜0.05), and therefore, the above unhealthy habits may be important risk factors.Toxoplasma infection could lead to adverse pregnancy outcomes. Therefore, the above-mentioned unhealthy habits should be avoided, especially during pregnancy period.[摘要] 目的调查河北省霸州地区不良妊娠史孕妇弓形虫感染状况及其危险因素。 方法 选择2012年3月至2015 年12月廊坊市第四人民医院妇产科接诊的不良妊娠史孕妇302例为调查对象 (实验组), 正常对照组为产前检查无异常 妊娠史的孕妇197例。采用酶联免疫吸附法检测2组孕妇血清弓形虫IgG (TOX-IgG) 和IgM抗体 (TOX-IgM) 含量。同时, 对2组孕妇进行弓形虫感染危险因素问卷调查。收集整理数据并进行统计分析。 结果 实验组弓形虫抗体总阳性率为 28.15% (85/302), 对照组总阳性率为9.64% (19/197), 差异有统计学意义 (χ2 = 24.76, P < 0.05)。其中实验组TOX-IgM阳 性率为6.95% (21/302), TOX-IgG阳性率为18.54% (56/302), TOX-IgM和TOX-IgG同为阳性者占2.65% (8/302), 均高于对 照组的2.03% (4/197)、7.61% (15/197) 和0 (0/197) (χ2 值分别为6.07、11.67、3.76, P 均< 0.05)。调查显示弓形虫感染孕妇 中饲养宠物、菜板生熟不分、喜吃火锅或烧烤、吃生肉习惯、经常在外就餐等比例均明显高于未感染弓形虫的孕妇 (χ2 值 分别为22.57、3.96、5.87、7.40、4.86, P 均< 0.05), 提示上述不良生活或卫生习惯可能是孕妇感染弓形虫的重要危险因 素。 结论 弓形虫感染可导致不良妊娠的发生。避免与宠物密切接触、不吃未煮熟的肉类以及加强个人卫生防护等是 避免育龄妇女发生不良妊娠结局的有效途径。.
Objective— Recently, we have demonstrated that acute glucosamine-induced augmentation of protein O-linked β-N-acetylglucosamine (O-GlcNAc) levels inhibits inflammation in isolated vascular smooth muscle cells and neointimal formation in a rat model of carotid injury by interfering with NF-κB (nuclear factor-κB) signaling. However, the specific molecular target for O-GlcNAcylation that is responsible for glucosamine-induced vascular protection remains unclear. In this study, we test the hypothesis that increased A20 (also known as TNFAIP3 [tumor necrosis factor α-induced protein 3]) O-GlcNAcylation is required for glucosamine-mediated inhibition of inflammation and vascular protection. Approach and Results— In cultured rat vascular smooth muscle cells, both glucosamine and the selective O-linked N-acetylglucosaminidase inhibitor thiamet G significantly increased A20 O-GlcNAcylation. Thiamet G treatment did not increase A20 protein expression but did significantly enhance binding to TAX1BP1 (Tax1-binding protein 1), a key regulatory protein for A20 activity. Adenovirus-mediated A20 overexpression further enhanced the effects of thiamet G on prevention of TNF-α (tumor necrosis factor-α)–induced IκB (inhibitor of κB) degradation, p65 phosphorylation, and increases in DNA-binding activity. A20 overexpression enhanced the inhibitory effects of thiamet G on TNF-α–induced proinflammatory cytokine expression and vascular smooth muscle cell migration and proliferation, whereas silencing endogenous A20 by transfection of specific A20 shRNA significantly attenuated these inhibitory effects. In balloon-injured rat carotid arteries, glucosamine treatment markedly inhibited neointimal formation and p65 activation compared with vehicle treatment. Adenoviral delivery of A20 shRNA to the injured arteries dramatically reduced balloon injury–induced A20 expression and inflammatory response compared with scramble shRNA and completely abolished the vascular protection of glucosamine. Conclusions— These results suggest that O-GlcNAcylation of A20 plays a key role in the negative regulation of NF-κB signaling cascades in TNF-α–treated vascular smooth muscle cells in culture and in acutely injured arteries, thus protecting against inflammation-induced vascular injury.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)