Protective effect of hypoxia inducible factor-1α gene therapy using recombinant adenovirus in cerebral ischaemia-reperfusion injuries in rats.

Context: Hypoxia-inducible factor-1α (HIF-1α)-induced genes can improve blood circulation.Objective: To investigate brain protective effect of recombinant adenovirus-mediated HIF-1α (AdHIF-1α) expression and its mechanism.Materials and methods: Male SD rats were used to establish focal cerebral ischaemia-reperfusion (CIR) injury models and randomly divided into normal, sham, CIR, Ad and AdHIF-1α groups. Ad or AdHIF-1α (108 pfu/10 µL) were administered into lateral ventricle of rats in Ad and AdHIF-1α groups. Modified neurological severity score (mNSS), brain water content (BWC) and cerebral infarct volumes (CIVs) were analyzed, and HE staining was performed using the brain tissues. Furthermore, the expression of caspase-3 and HSP90 was analyzed using qRT-PCR and Western blotting.Results: Compared to CIR (mNSS, 8.52 ± 0.52; CIV, 0.22 ± 0.01) and Ad groups (mNSS, 8.83 ± 0.41; CIV, 0.22 ± 0.02), mNSS and CIV were significantly decreased in AdHIF-1α group (mNSS, 6.03 ± 0.61; CIV, 0.11 ± 0.01) at 72 h (p < 0.05). With prolonged reperfusion time (6 h to 72 h), BWC of all rats increased gradually, although the increase was markedly less in AdHIF-1α group (78.15 ± 0.16 to 87.01 ± 0.31) compared to that in CIR (78.77 ± 0.60 to 89.74 ± 0.34) and Ad groups (78.77 ± 0.35 to 89.71 ± 0.27) (p < 0.01). There were significantly greater pathological changes in the neurons in AdHIF-1α group at 72 h following CIR. Furthermore, expression of caspase-3 (p < 0.01) down-regulated and HSP90 up-regulated (p < 0.05) at mRNA and protein levels in AdHIF-1α group.Discussion and conclusions: HIF­1α gene therapy is neuroprotective towards the CIR rat model. HIF-1α may be a candidate gene for the treatment of ischaemic brain injury.

[Effect of repeated firings on fatigue behaviors of posterior occlusal veneers made of glass ceramic].

PURPOSE: To investigate the effect of firing times on the fatigue properties and failure modes of posterior occlusal veneers made of lithium disilicate glass ceramics. METHODS: According to the number of times of firing (1, 3, 5, 7 times), IPS e.max CAD(IC) and IPS e.max Press(IP) occlusal veneer restorations with a thickness of 1.2mm were prepared, and then cemented to the maxillary molar composite resin dies. Each group was subjected to thermo-mechanical fatigue(TMFT) test (5-55 ℃, 5000 cycles, 30-300 N, 10 Hz, sinusoidal wave, 500 000 cycles) and compressive loading. The maximum force at fracture was recorded. Stereomicroscope and scanning electron microscope(SEM), energy dispersive X-ray spectroscopy(EDX) and X-ray diffraction(XRD) were adopted to analyze the failure modes and microstructural features. Statistical analysis was performed with SPSS 20.0 software package. RESULTS: The highest average loads (N) at fracture for IC groups were (1546.73±192.85) N after one firing time; in IP group, the highest average loads were (1504.46±138.56) N after three firing times. There was no significant difference in the fracture load with different firing times for IC/IP(P>0.05). EDX and XRD analysis showed no significant difference in the composition of two materials. SEM showed that the size of crystal was shorter and the porosity increased after multiple firing. CONCLUSIONS: After repeated firing, the fatigue loading of lithium disilicate glass ceramics has a decreasing trend of fracture load value without any significant difference, and it meets clinical requirements.

The primary microbial pathogens associated with premature rupture of the membranes in China: a systematic review.

To describe the spectrum of pathogens isolated from Chinese women experiencing premature rupture of the membranes (PROM) and those of their neonates, in order to provide effective management of PROM. We searched Ovid Medline, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, and VIP Database for Chinese Technical Periodicals up to April 2012. The quality of studies was assessed utilizing the Strengthening the Reporting of Observational Studies in Epidemiology Statement. Among the included 36 studies, 11 (30.55%) were deemed to be at Level A, 12 (33.33%) at Level B, three (8.33%) at Level C, and 10 (27.78%) at Level D. Staphylococcus and Escherichia coli were the two primary microorganisms isolated from women with PROM and their infants. Subgroup analysis showed the distribution of microorganisms from the six regions of China varied. Staphylococcus bacteria were resistant to penicillins, except oxacillin, but more sensitive to first- and second-generation cephalosporins. Escherichia were sensitive to first- and second-generation cephalosporins and were more sensitive to aztreonam than cephalosporins. The main pathogens derived from women with PROM and their newborns were Staphylococcus and E. coli, which differs from the pathogens in Western countries. Hence, one might infer that the pathogens involved in PROM should be defined in each region to maximize antibiotic effectiveness. In addition, randomized controlled studies are needed to compare prophylactic use of antibiotics versus use of antibiotics after a positive culture for newborn infants with a history of PROM.