In vivo evaluation of the interaction between titanium dioxide nanoparticle and rat liver DNA.

Titanium dioxide nanoparticles (TiO2 NPs) are massively produced and widely used in daily life, which may pose potential risk to human health via uncharacterized interaction between DNAs. This research aims to examine the interaction between DNA and three types of TiO2 NPs of different sizes and crystallines. The interaction between TiO2 NPs and liver DNA molecules obtained from Sprague-Dawley rats was systematically evaluated in vivo using atomic force microscopy, transmission electron microscopy, various spectroscopic techniques and gel electrophoresis. We found that TiO2 NPs (diameter <25 nm and <100 nm) in anatase crystalline can covalently interact with liver DNA by either inserting itself in between DNA base pairs or binding to DNA nucleotide via P-O-Ti-O bond. Such interaction may not be NP size-dependent but may be crystalline phase-dependent, because such interaction did not occur in rutile crystal phase, in which the DNA damage was potentially caused by reactive oxygen species.

C2 pedicle screw insertion assisted by mobilization of the vertebral artery in cases with high-riding vertebral artery / 中华外科杂志

Objective: To examine the feasibility, safety, and efficacy of mobilization of the vertebral artery for C2 pedicle screws in cases with high-riding vertebral artery (HRVA). Methods: The clinical data of 12 patients with basilar invagination and atlantoaxial dislocation underwent atlantoaxial reduction and fixation in the Department of Neurosurgery, the First Affiliated Hospital of University of Science and Technology of China between January 2020 and November 2021 were retrospectively analyzed. All patients had high-riding vertebral artery on at least one side that prohibited the insertion of C2 pedicle screws. There were 2 males and 10 females aged (48.0±12.8) years (range: 17 to 67 years). After correction of vertical dislocation during the operation, the C2 pedicle screw insertion and occipitocervical fixation and fusion were performed using the vertebral artery mobilization technique. Neurological function was assessed using the Japanese Orthopedic Association (JOA) scale. The preoperative and postoperative JOA score and the main radiological measurements, including the anterior atlantodental interval (ADI), the distance of the odontoid tip above the Chamberlain line, the clivus-canal angle, were collected and compared by paired t-test. Results: Mobilization of the high-riding vertebral artery was successfully completed, and C2 pedicle screws were then fulfilled after the vertebral artery was protected. There was no injury to the vertebral artery during the operation. Meanwhile, no severe surgical complications such as cerebral infarction or aggravated neurological dysfunction occurred during the perioperative period. Satisfactory C2 pedicle screw placement and reduction were achieved in all 12 patients. All patients achieved bone fusion 6 months after surgery. No looseness and shift in internal fixation or reduction loss was observed during the follow-up period. Compared to the preoperative, the postoperative ADI decreased from (6.1±1.9) mm to (2.0±1.2) mm (t=6.73, P<0.01), the distance of the odontoid tip above the Chamberlain line decreased from (10.4±2.5) mm to (5.5±2.3) mm (t=7.12, P<0.01), the clivus-canal angle increased from (123.4±11.1) ° to (134.7±9.6) ° (t=2.50, P=0.032), the JOA score increased from 13.3±2.1 to 15.6±1.2 (t=6.99, P<0.01). Conclusion: The C2 pedicle screw insertion assisted by mobilization of the vertebral artery is safe and considerably effective, providing a choice for internal fixation in cases with high-riding vertebral arteries.

Identification and drug susceptibility testing of Mycobacterium thermoresistibile and Mycobacterium elephantis isolated from a cow with mastitis / 中华流行病学杂志

Objective: To understand the etiological characteristics and drug susceptibility of Mycobacterium thermoresistibile and Mycobacterium elephantis isolated from a cow with mastitis and provide evidence for the prevention and control of infectious mastitis in cows. Methods: The milk sample was collected from a cow with mastitis, which was pretreated with 4% NaOH and inoculated with L-J medium for Mycobacterium isolation. The positive cultures were initially identified by acid-fast staining and multi-loci PCR, then Mycobacterium species was identified by the multiple loci sequence analysis (MLSA) with 16S rRNA, hsp65, ITS and SodA genes. The drug sensitivity of the isolates to 27 antibiotics was tested by alamar blue assay. Results: Two anti-acid stain positive strains were isolated from the milk of a cow with mastitis, which were identified as non-tuberculosis mycobacterium by multi-loci PCR, and multi-loci nucleic acid sequence analysis indicated that one strain was Mycobacterium thermoresistibile and another one was Mycobacterium elephantis. The results of the drug susceptibility test showed that the two strains were resistant to most antibiotics, including rifampicin and isoniazid, but they were sensitive to amikacin, moxifloxacin, levofloxacin, ethambutol, streptomycin, tobramycin, ciprofloxacin and linezolid. Conclusions:Mycobacterium thermoresistibile and Mycobacterium elephantis were isolated in a cow with mastitis and the drug susceptibility spectrum of the pathogens were unique. The results of the study can be used as reference for the prevention and control the infection in cows.

The Wuhan Twin Birth Cohort Study / 中华流行病学杂志

The prevalence of child and adolescent growth and mental-behavior related diseases are increasing, and the pathogenesis are complex. Twins are excellent natural resources for complex chronic diseases research as they share the maternal intrauterine environment, born at the same time and share the same family environment in early years, which could benefit the adjust ment of confounding factors, such as age, genetic factors and early family environmental factors. Birth cohort with twin families involved could be more effective in exploring the genetic and environmental factors for complex chronic diseases at the very beginning of life. This paper summarizes the objective, content, progress, strengths and potential problems of Wuhan Twin Birth Cohort, with emphasis on the overall design and progress of the study.

Cellular toxicity of TiO2 nanoparticles in anatase and rutile crystal phase.

Titanium dioxide nanoparticles are massively produced and widely used in daily life, which has posed potential risk to human health. However, the molecular mechanism of TiO(2) nanoparticles (NPs) with different crystal phases is not clear. In this study, the characterization of two crystalline phases of TiO(2) NPs is evaluated by transmission electron microscopy and X-ray absorption fine structure spectrum; an interaction of these TiO(2) NPs with HaCaT cells is studied in vitro using transmission electron microscopy, chemical precipitation method, and X-ray absorption fine structure spectrometry. The coordination and surface properties indicate that only the anatase-TiO(2) NPs allow spontaneous reactive oxygen species (ROS) generation, but rutile-TiO(2) NPs do not after dispersion. The interaction between TiO(2) NPs and cellular components might also generate ROS for both anatase-TiO(2) NPs and rutile-TiO(2) NPs. The ROS generation could lead to cellular toxicity if the level of ROS production overwhelms the antioxidant defense of the cell or induces the mitochondrial apoptotic mechanisms. Furthermore, Ti had a direct combination with some protein or DNA after NPs enter the cell, which could also lead to cellular toxicity.