TPGS-based and S-thanatin functionalized nanorods for overcoming drug resistance in Klebsiella pneumonia.

Tigecycline is regarded as the last line of defense to combat multidrug-resistant Klebsiella pneumoniae. However, increasing utilization has led to rising drug resistance and treatment failure. Here, we design a D-alpha tocopheryl polyethylene glycol succinate-modified and S-thanatin peptide-functionalized nanorods based on calcium phosphate nanoparticles for tigecycline delivery and pneumonia therapy caused by tigecycline-resistant Klebsiella pneumoniae. After incubation with bacteria, the fabricated nanorods can enhance tigecycline accumulation in bacteria via the inhibitory effect on efflux pumps exerted by D-alpha tocopheryl polyethylene glycol succinate and the targeting capacity of S-thanatin to bacteria. The synergistic antibacterial capacity between S-thanatin and tigecycline further enhances the antibacterial activity of nanorods, thus overcoming the tigecycline resistance of Klebsiella pneumoniae. After intravenous injection, nanorods significantly reduces the counts of white blood cells and neutrophils, decreases bacterial colonies, and ameliorates neutrophil infiltration events, thereby largely increasing the survival rate of mice with pneumonia. These findings may provide a therapeutic strategy for infections caused by drug-resistant bacteria.

Effects of different electrolytes for micro-arc oxidation on the bond strength between titanium and porcelain.

PURPOSE: The aim of this study is to investigate the effects of different electrolytes on the titanium-porcelain bond strength after micro-arc oxidation (MAO) treatment. METHODS: Three electrolytes at the same concentration were used as MAO reaction solutions: Na2SiO3, KF, and MgSiF6. Blasting treatment was chosen as a control. After MAO treatment in each electrolyte, the titanium-porcelain bond strengths were measured by the three-point bending test, as described in ISO 9693. The morphologies and elemental compositions of the MAO coating on the titanium substrate were evaluated by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The interface between the titanium and porcelain was also observed by SEM and EDS. RESULTS: The MAO coatings created in different electrolytes exhibited completely different morphologies and compositions. The bond strengths of the Na2SiO3 and MgSiF6 groups were significantly higher than those of the other groups (p<0.05). Additionally, the titanium-porcelain interfaces were compact in the former two groups, whereas pores and cracks were visible at the interfaces in the other groups. CONCLUSIONS: These results indicate that MAO treatment with an appropriate electrolyte could be an effective method to increase the titanium-porcelain bonding strength. According to ISO 9693, titanium-porcelain restorations subjected to MAO treatment with an appropriate electrolyte could be appropriate for clinical use.

[Association of HLA-DRB1*1501 polymorphism with the susceptibility to severe chronic periodontitis in Chinese Han nationality].

PURPOSE: To investigate the association of HLA-DRB1*1501 polymorphism with the susceptibility to severe chronic periodontitis (CP) in Chinese Han nationality. METHODS: DNA samples were collected with buccal swabs from 134 subjects with severe chronic periodontitis and 81 periodontal healthy control. HLA-DRB1*1501 genotype was determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The genotype distribution was statistically analyzed by chi2 test. RESULTS: The allele frequencies of DRB1*1501 was detected more frequently in severe CP patients than in the controls [OR=3.874 (2.401-6.252), P<0.05]. The 1501/1501 genotype frequencies were significantly increased in patients compared with the reference population [OR=20.896 (4.866-89.726), P<0.05]. CONCLUSION: The results suggest that HLA-DRB1*1501 allele may be a risk indicator for the susceptibility to severe CP in Han nationality (P<0.05). The HLA-DRB1*1501 homozygote genotype was associated significantly with severe CP (P<0.05).