BACKGROUND:Steam sterilization is a commonly used oral clinical method of disinfection, but whether it would produce more significant impact on equipments waiting for sterilization has been controversial.
OBJECTIVE:To investigate the effect of autoclave on two kinds of orthodontic distal end cutters by comparing shearing force and corrosion after sterilization.
METHODS:Tiantian (n=15) and 3M (n=15) distal end cutters commonly used in orthodontic treatment were chosen for testing and divided into three groups, respectively. Three groups for each kind of cutter were treated with high-pressure steam sterilization, steam sterilization+extraoral shear, and steam sterilization+intraoral shear, respectively. The shearing force and metal ography of the distal end cutters were recorded after 0, 20, 40, and 60 cycles of sterilization. An energy dispersive spectrometer was used to scan the surfaces of the working edges of the distal end cutters after 60 cycles.
RESULTS AND CONCLUSION:It was found that with an increase in the number of sterilization cycles, the shear force and extent of corrosion increased in al six groups of distal end cutters, but the situation was worse for Tiantian cutters than for 3M cutters. It was found that the difference of shear force between the Tiantian autoclave group and 3M autoclave group was statistical y significant (P<0.05) after 20, 40, and 60 sterilization cycles. Meanwhile, the metal ography showed that different degrees of discoloration and rust spots appeared on the work edges of the two brands of distal end cutters with an increase in the number of sterilization cycles, but the corrosion of the Tiantian distal-end cutter was more widespread, and even work-edge defects appeared. The carbon content of the Tiantian distal-end cutter was higher than that of the 3M cutter (P<0.05), but the chromium content was higher in the 3M cutter (P<0.05). In addition, aluminum and titanium elements only existed in the 3M cutter. The use of the autoclave affected the distal end cutters in terms of shearing force and corrosion, but the effect on 3M distal end cutters was obviously less than that on Tiantian cutters.

To investigate the electrophysiologic characteristics of f-wave amplitude and to evaluate its role in development and persistence of chronic atrial fibrillation (AF) associated with rheumatic heart disease (RHD). Methods: Epicardial mapping was performed in 44 patients with chronic AF of RHD who underwent heart valve surgery. Ten patients with supraventricular tachycardia served as the control group. Results:The f-wave amplitude of left atrium (LA) and middle and low LA posterior regions were significantly lower than those of the control group. The f-wave amplitudes of the upper, middle and low sections in LA posterior region were significantly lower than those in right atrium (RA) (P<0.05). The f-wave amplitudes were compared before and after electrocardioversion in 14 patients with chronic AF. The mean atrial electrogram amplitude during sinus rhythm was significantly higher than that during AF (P<0.01).The f-wave amplitude in left appendage was higher than that in LA posterior region (the upper,middle and the lower part),P<0.05.The f-wave amplitude in the upper section of LA was significantly higher than that in the middle section. The f-wave amplitude in AF group was not correlated to the diameter or volume of both atria. Conclusion: There are amplitudes differences between the upper, middle and lower LA,suggesting that the middle and lower sections of LA posterior wall may be the region producing anisotropy and reentrant circle.

BACKGROUND:In previous experiments, TiO2-xNy OBJECTIVE:To study the friction properties of orthodontic brackets coated with TiO-coated bracket has been confirmed to have excelent antibacterial properties and biological safety performance. 2-xNy METHODS: TiO film. 2-xNy film was prepared by radiofrequency magnetron sputtering on MBT bracket (0.022″). The TiO 2-x N y RESULTS AND CONCLUSION: TiO-coated brackets were analyzed by X-ray diffraction and scanning electron microscopy observations. The coefficient of static friction and coefficient of kinetic friction between the wires (0.012″, 0.014″, 0.016″) and orthodontic brackets were calculated. 2-xNy film on the bracket was of anatase structure, which was compact and had good crystalinity. Under dry condition, the coefficient of static friction and kinetic friction of the brackets coated with TiO2-xNy were less than those of ordinary brackets; under wet condition, the coefficients of static friction and kinetic friction of the brackets coated with TiO2-xNy were less than those of ordinary brackets, but the difference was not statisticaly significant. Nano-TiO2-xNy film can reduce the friction between bracket and archwire, which wil offer a novel opportunity to significantly reduce the friction during tooth movement.

0.05).Meanwhile,the percentage of elongation increased following each recasting(P

Objective To compare the efficacy of sedation with dexmedetomidine versus midazolam in mechanically ventilated patients.Methods Sixty patients aged 20-64 yr,with body mass index 21-25 kg/m2,APECHE Ⅱ score 10-25,requiring 24 h of nechanical ventilation in intensive care unit (ICU),were randomly divided into 2 groups (n=30 each): midazolam group (group M) and dexmedetomidine group (group D).A loading dose of midazolam 0.05 mg/kg was injected intravenously,followed by infusion at 0.03-0.20 mg· kg-1 · h-1 in group M.A loading dose of dexmedetomidine 1 μg/kg was injected intravenously,followed by infusion at 0.2-0.7 μg· kg-1 · h-1 in group D.Ramsay sedation score was maintained at 2-4.The satisfaction of the doctors in ICU with the sedative efficacy,hypotension and bradycardia were recorded.Delirium was recorded starting from the begging of sedation to 2 h after the end of sedation.The emergence time and occurrence of falling asleep again within 2 h after waking were also recorded.Results Compared with M group,the satisfactory level of the doctors in ICU with the sedative efficacy was significantly increased,the emergence time was significantly shortened and the incidences of falling asleep again within 2 h after waking and delirium were significantly decreased (P ＜ 0.05 or 0.01),and no significant change was found in the incidence of hypotension and bradycardia in group D (P ＞ 0.05).Conclusion The efficacy of sedation with dexmedetomidine is better than that of midazolam in mechanically ventilated patients.

Objective To assess the factors which affect the activity of isolated islets,and to construct a steady and effective isolation method of rat pancreatic islets.Methods Pancreatic islets were isolated by collagenase method.The glucose-stimulation of insulin secretion(GSIS) in different conditions was performed by batch incubation method and measured by RIA.Results GSIS was improved by BSA;There was a evident decrease of insulin secretion in cultured islets of 7 days,however,no difference was observed between the freshly isolated islets group and the 1～5days cultured islets groups.Compared to the groups of(5.5 mmol/L) and(25 mmol/L) glucose in the culture medium,(11.1 mmol/L) glucose group stimulated higher insulin release.Conclusion BSA,glucose concentration of RPMI1640 medium and the culture period are related to the activity of isolated islets.

Total mRNA was extracted from lymphocytes separated from the peripheral blood of allergic patients, and then variable region of heavy chain (VH) and variable region of light chain (VL) cDNA library were constructed by RT-PCR. Human scFv templates for rabbit reticulocyte lysate ribosome display were assembled by primers and linker peptide (Gly4Ser)3. mRNA bound in antibody-ribosome-mRNA complexes was recovered using in-situ single primer RT-PCR, and three rounds of anti-IgE scFv DNA were enriched. The target DNA fragments were double enzyme digested and ligated into plasmid pET22b (+), followed by transformation in E. coli Rosseta (DE3). Positive clones were screened using clone PCR, Dot blotting and antigen ELISA. The correct lengths of VH (400 bp) and VL (710 bp) PCR products were obtained. The expected 1,000 bp ribosome display templates were also observed in agarose gel electrophoresis. After three rounds of ribosome display target sequences were effectively enriched, leading to a library of 10(13) members. Antibodies with the highest ELISA value for IgE were generated in the strain pET-IgE-6. A human anti-IgE scFv library was successfully constructed as described herein. Ribosome display using single primer in-situ RT-PCR as the recovery procedure effectively enriched target sequences. Anti-IgE scFv with high affinity and specificity were identified. The prepared human anti-IgE scFv fragment might be self-developed to a lead drug for treating asthma. Our study provides an alternative method for rapid discovery of human antibodies of therapeutic importance.

Objective To study the adjuvant effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) coding gene on cellular immunity induced by Japanese encephalitis (JE) virus DNA vaccine. Methods GM-CSF coding gene was amplified by nested-reverse transcriptase-polymerase chain reaction (RT-PCR) technique from BALB/c murine spleen cells. Recombinant plasmids pJME/GM-CSF and pGM-CSF were constructed by JE virus (JEV) prM-E protein with GM-CSF coding gene or GM-CSF coding gene only, respectively. The plasmids were transfected into China hamster ovary (CHO) cells by Lipofectamine 2000. The coding protein expressions and distributions were detected by immunofluorescence. The BALB/c mice were vaccinated with indicated immunogens with or without GM-CSF gene. The changes of T lymphocyte subsets in the spleen and levels of intracellular cytokines, such as interferon (IFN)-γ and interleukin (IL)-4 of splenic cells from mice immunized with different immunogens were evaluated by flow cytometry. The cytotoxicity T lymphocyte (CTL) activity was assessed by lactate dehydrogenase (LDH). The data were compared by one-factor analysis of variance and least significant difference. Results The constructed recombinant pGM-CSF and pJME/GM-CSF were confirmed by restrict enzyme digestion and DNA sequencing. The expressions of the above proteins were mainly in the cytoplasm and minor on cell membrane. The percentage of CD4+ T lymphocytes in pJME/GM-CSF vaccinated group was (33.90±0.79)%, which was significantly higher than that of in other groups (t values were 9. 818, 6. 804, 6.594, 10.061, 9.380, and 17.675, all P<0.05). The percentages of CD4+T lymphocytes in pJME +pGM-CSF (0) and pJME+pGM-CSF (-3) vaccinated groups were (29.83±0.61)% and (29.70±0.51)%, respectively, which were both higher than that in pJME+pGM-CSF (+3) vaccinated group of (27.69+0.50)% (t=3.466, t=3.255, both P<0.05). The percentages of CD8+ T cells in pJME/GM-CSF and pJME+pGM-CSF vaccinated groups were both higher than that in empty vector (pcDNA 3.1+) group and JE inactivated vaccine vaccinated group (t values were 3.811, 2.627, 10.537, and 3.811, all P<0.05). The CTL activity in pJME/GM-CSF vaccinated group was (51.48±0.10)%, which was higher than those in other groups (t values were 22.868, 13.823, 5.377, 32.287, 34.632, and 53.795, all P<0.05). The IFN-γ/IL-4 ratios in pJME/GM-CSF, pJME+pGM-CSF (0) and pJME + pGM-CSF (-3) vaccinated groups were (19.13±1.36), (12.32±0.82) and (7.05±0.43), respectively, which were higher than those in other groups (P<0.05). Conclusion GM-CSF coding gene could enhance the cellular immune response induced by Japanese encephalitis DNA vaccine.

Objective:To assess the possibility of suicide in setting condition among urban and rural residents samples in northern China.Methods:By randomly sampling,1007 persons aged 18 years or older were selected from 10 urban neighborhoods in Beijing and from 10 rural village in Hebei province.The Survey Schedule of Atti-tudes in China in which 24 negative life events were listed,and the possibility of committing suicide was asked to the subjects when they encountered the supposed events.Results:The rates of thinking about committing suicide when encountered the supposed life events were 65.2% of incurable illness,62.0% of burden on other and no future hope,61.2% of drug dependence,57.3% of large debt due to gambling,54.2% of being raped, 51.6% of severe depression,50.7% of being elderly and no family to provide support.Only 14.6% of the ur-ban and rural residents would not consider suicide when encountered any type of supposed problems.Conclusion:There is higher possibility of considering suicide in urban and rural residents when encountered negative life events, so it is important to give support to the residents with one or more life events.

In February, 2019, a patient with a defect of open dorsal cartilage and bone in the first metatarsal head, including the defects of soft tissue, tendon and joint capsule, was treated in our department. After multiple debridement, the vascularised medial femoral condyle osteochondral chimeric tissue flap was transferred to repair the composite tissue defect in the metatarsal head at the second stage. After 18 months of follow-up, the patient felt no pain in the foot and walking, and there was no sign of lameness and discomfort at donor sites. The postoperative functional recovery was satisfactory.