Long-term antibacterial composite via alginate aerogel sustained release of antibiotics and Cu used for bone tissue bacteria infection

Bone related-bacterial diseases including wound infections and osteomyelitis (OM) remain a serious problem accompanied with amputation in most severe cases. In this work, we report an exceptional effective antibacterial alginate aerogel, which consists of tigecycline (TGC) and octahedral Cu crystal as an organo-inorganic synergy platform for antibacterial and local infection therapy applications. The alginate aerogel could greatly prolong the release of copper ions and maintain effective antibacterial concentration over 18 days. The result of in-vitro experiments demonstrated that the alginate aerogel has an exceptional effective function on antibacterial activity. Cytotoxicity tests indicated that the alginate aerogel has low biological toxicity (average cell viability >75%). These remarkable results suggested that the alginate aerogel exhibits great potential for the treatment of OM, and has a prosperous future of application in bone tissue engineering.

Capsule switching of Neisseria meningitidis sequence type 7 serogroup A to serogroup X

OBJECTIVES

The bacterial pathogen Neisseria meningitidis is able to escape the currently available capsule-based vaccines by undergoing capsule switching. In this study, we investigated whether capsule switching has occurred in a recently emerged sequence type (ST) 7 serogroup X isolate in China, for which currently no vaccine is available.

METHODS

To identify capsule switching breakpoints, the capsule locus and flanking regions of the ST-7 serogroup X isolate and three endemic ST-7 serogroup A isolates were sequenced and compared. To obtain further insight into capsule switching frequency and length of DNA fragments involved, capsule switching assays were performed using genomic DNA containing combinations of antibiotic selection markers at various locations in the capsule locus and flanking regions.

RESULTS

Sequence analyses showed that capsule switching has occurred and involved a 8450 bp serogroup X DNA fragment spanning the region from galE to ctrC. Capsule switching assays indicate that capsule switching occurs at a frequency of 6.3 × 10^-6 per bacterium per μg of DNA and predominantly involved DNA fragments of about 8.1-9.6 kb in length.

CONCLUSIONS

Our results show that capsule switching in N. meningitidis occurs at high frequency and involves recombination in the flanking regions of the capsule biosynthesis genes.

[The expression and significance of heparanase in oral squamous cell carcinoma with different metastatic potentials]

Objective: To detect the expression of heparanase (HPSE) in oral squamous cell carcinoma (OSCC) with different metastatic potentials and investigate its clinical significance. Methods: Transcriptional and translational status of HPSE in OSCC cell lines with different metastatic capacities, primary OSCC samples and their paired metastatic cancer tissues were determined using real-time polymerase chain reaction (PCR) and Western blotting analysis. Immunohistochemistry was used to evaluate HPSE expression in 131 OSCC samples. The correlation between HPSE expression pattern and clinicopathological parameters and clinical outcome in patients with OSCC were analyzed. HPSE level was reduced using HPSE-siRNAs in OSCC cell lines and its impact on cell migration and invasion was measured by scratch assay and matrigel invasion assay. Results: The mRNA and protein levels of HPSE were remarkably up-regulated in OSCC cell lines with highly metastatic capacity (P<0.000 1) and metastatic OSCC tissues (P<0.000 1). The protein levels of HPSE were strongly associated with lymph node metastasis (P<0.000 1) and tumor node metastasis stage (P=0.012). Survival analyses revealed that high HPSE expression was associated with worse overall survival (P=0.000 3). Multivariate Cox proportional analyses indicated that HPSE expression was strongly associated with clinical outcome in patients with OSCC (HR=2.203, 95% CI: 1.203-3.988, P=0.009). The siRNA-mediated silencing of HPSE could suppress the migration and invasion (P=0.008) of HN12 cells in vitro. Conclusions: The up-regulation of HPSE contributes to invasion and metastasis of OSCC. HPSE may serve as a useful biomarker for patients with OSCC.

Copper(II) complexes with N,N'-dialkyl-1,10-phenanthroline-2,9-dimethanamine: synthesis, characterization, DNA-binding thermodynamical and kinetic studies

Copper(II) complexes (Cu-L, L=N,N'-dialkyl-1,10-phenanthroline-2,9-dimethanamine) were synthesized and characterized by elemental analyses, IR spectra and conductance measurement. The interaction of the copper(II) complex with calf thymus DNA was studied by means of UV melting experiments, fluorescence spectra and circular dichroic spectra. Using ethidium bromide as a fluorescence probe, the binding mode of the complexes Cu-L with calf-thymus DNA was studied spectroscopically. The results indicate that the complexes Cu-L perhaps interact with calf-thymus DNA by both intercalative and covalent binding. Kinetics of binding of the cupric complexes to DNA was studied for the first time using ethidium bromide as a fluorescence probe with stopped-flow spectrophotometer under pseudo-first-order condition. The stronger binding of two steps in the process of the complexes Cu-L interacting with DNA was observed, and the probable interaction process was discussed in detail. The corresponding k(obs) and E(a) of binding to DNA (where k(obs) is the observed pseudo-first-order rate constant, E(a) is the observed energy of activation) were obtained.

[A survey of the changes of serum inorganic salts and alkaline phosphatase after jaw fractures]

OBJECTIVE

To study the changes of serum salts and alkaline phosphatase in patients with jaw fractures and its roles.

METHODS

The serum salts and alkaline phosphatase were determined in 40 cases of jaw fracture and 14 health persons.

RESULTS

The results showed that there was no significant difference in Na(+), K(+), Cl(-), Ca(2+) contents between jaw fracture group and normal group (P>0.05), but P(3-) Mg(2+), ALP levels were higher in jaw fracture group than that in normal group (P<0.05). Furthermore the Ca(2+), P(3-), Mg(2+), ALP were higher in multiple or communition fracture of jaw than in single or double line fracture (P<0.05) except Ca content. The level of Ca(2+) was higher in single jaw fracture than in jaw damage with whole body injury (P>0.05) but the levels of P(3-),Mg(2+), ALP were no difference (P>0.05). As the same all the Ca(2+), P(3-), Mg(2+), ALP levels were higher in early stage of fracture than in 4 weeks after fracture (P<0.05).

CONCLUSION

The contents of Ca(2+) P(3-), Mg(2+) ALP were increased after the axilla mandible were fractured and it has an important regulation role in the activity of osteoblast and osteoclast in healing of fractured jaw.

Synthesis, characterization and cytotoxicity of lanthanum(III) complexes with novel 1,10-phenanthroline-2,9-bis-alpha-amino acid conjugates

Eight lanthanum(III) complexes with novel 1,10-phenanthroline-2,9-bis-alpha-amino acid conjugates were synthesized and characterized by elemental analyses, IR, MS, 1H-NMR, thermal analysis and conductance measurement. All lanthanum(III) complexes and the corresponding soluble ligand in water have been assayed for antitumor activity in vitro against HL-60 (human leukocytoma) cells, HCT-8 (human coloadenocarcinoma) cells, BGC-823 (human stomach carcinoma) cells, BeL-7402 (human liver carcinoma) cells and KB (human nasopharyngeal carcinoma) cells. The results show that several complexes have relative activity against different cell lines. In particular, the complexes La(L2) and La(L5) show relatively high activity against the BeL-7402 cell line. Moreover, they are slightly more effective than cisplatin. DNA binding studies indicate that the complex La(L2) possibly interacts with calf thymus DNA by both intercalative and covalent binding.

[An experimental study on dental pulp histology after the inferior alveolar nerve damage and autogenous nerve graft]

The dental pulpal histology was studied experimentally in rabbits after the inferior alveolar neurovascularity damage and nerve graft. The results revealed that the dental vitality was gradually repaired at different intervals after the inferior alveolar neurovascularity damage. In the early damaged period the pulpal blood vessels were reduced in number and some of them were swollen and permeable, in the late period the structure of the microvascular system became normal and abundant. The pulpal architecture was altered in the initial stage and with the tendency to repair gradually. The pulpal axon degenerated in early stage and reinnervated later. The authors indicate that there are no evident affections for dental pulpal tissues whatever the inferior alveolar neurovascularity is damaged and repaired. This has an important clinical value to define the dental pulp vitality in mandibular subapical osteotomy and tumor resection.

[The clinical observation of 247 tuberculosis cases in Oral Maxillofacial region]

This paper presents a report of clinical observation on tuberculosis of oral and maxillofacial region in 247 patients.Of these which diagnosed by histopathology.94 cases are from mucous membrane of oral cavity,108 subjects from lymph nodes,27 ones from parotid gland,15 persons from facial dermis and 3 from jaw.Among 247 patients.154 cases were male and 93 female.The youngest was 2 years old and the eldest one was 71 of age and the mean age was 32 years old.The shortest course of disease was 15 days and the longest was 30 years,the mean course of time was two and half years.The rate of clinical diagnosis accord with pathology was 41.3%,most error diagnosis were to suspect inflammation,tumors and ulcer.In addition,the etiology,the clinical manifestion,diagnosis and therapies of oral and maxillofacial tuberculosis were analyzed.

A comparative experimental study on primary and secondary nerve grafting following inferior alveolar nerve injury

The damaged inferior alveolar nerve of rabbit was repaired with autogenous ipsilateral greater auricular nerve grafting primarily and secondarily, and electrophysiological, ultrastructural, microvascular and histochemical investigations were performed in this study. The results indicated that the experimental effects of group 1 out of 3 groups (group 1 with immediate grafting, group 2 with grafting after 4 weeks, and group 3 with grafting after 8 weeks) were the best and those of group 2 were second only to group 1 with no obvious difference between these two groups (P greater than 0.05). However, the results of group 3 were not good enough, and there was significant difference from the other two groups (P less than 0.05). Therefore, we were led to conclude that the injury should be repaired at once or within 4 weeks after inferior alveolar nerve was damaged, or within 2 or 3 months thereafter, to improve the function of the injured nerve as greatly as possible.