Current Practice of Acute Appendicitis Diagnosis and Management in China (PANDA-C): A National Cross-Sectional Survey.

Background: The aim of this study was to describe and analyze the current status of the diagnosis and management of acute appendicitis in China. Patients and Methods: An online record system was used to collect data retrospectively from 52 medical centers in mainland China. All patients with acute appendicitis who were first treated at the hospital in 2017 were included and followed up for one year. Propensity score matching (PSM) was used to exclude the potential confounders and analyze the difference in outcomes between the non-operative management (NOM) and surgical groups. Results: A total of 10,187 patients were enrolled, of whom 5,517 (54.2%) were males. A total of 2,056 (20.2%) cases received NOM. The one-year recurrence rate of appendicitis in the NOM group was 19.3%. On PSM analysis, we found that the NOM group had a lower complication rate (2% vs. 4.2%; p = 0.001) and an acceptable success rate (96.8% vs. 100%; p < 0.001) compared with the operative group in patients with non-complicated acute appendicitis. However, in the complicated acute appendicitis population, the in-hospital complication rate in the NOM group was higher (10.8% vs. 5.8%; p = 0.048) and the success rate was lower (95.4% vs. 100%; p < 0.001) than the operative group. The recurrence rate was lower in patients with non-complicated acute appendicitis than in those with complicated acute appendicitis (17.3% vs. 30.8%; p = 0.010). In the operative group, pre-operative antimicrobial prophylaxis-covered anaerobes could reduce the surgical site infection (SSI) rate compared with that in the non-covered anaerobes group in non-complicated patients (0.9% vs. 1.9%; p = 0.020). Conclusions: Appendectomy is currently the most effective treatment for acute appendicitis. However, NOM is an alternative treatment for non-complicated acute appendicitis but not for complicated acute appendicitis because of the lower complication rate, considerable success rate, and recurrence rate.

Ohr and OhrR Are Critical for Organic Peroxide Resistance and Symbiosis in Azorhizobium caulinodans ORS571.

Azorhizobium caulinodans is a symbiotic nitrogen-fixing bacterium that forms both root and stem nodules on Sesbania rostrata. During nodule formation, bacteria have to withstand organic peroxides that are produced by plant. Previous studies have elaborated on resistance to these oxygen radicals in several bacteria; however, to the best of our knowledge, none have investigated this process in A. caulinodans. In this study, we identified and characterised the organic hydroperoxide resistance gene ohr (AZC_2977) and its regulator ohrR (AZC_3555) in A. caulinodans ORS571. Hypersensitivity to organic hydroperoxide was observed in an ohr mutant. While using a lacZ-based reporter system, we revealed that OhrR repressed the expression of ohr. Moreover, electrophoretic mobility shift assays demonstrated that OhrR regulated ohr by direct binding to its promoter region. We showed that this binding was prevented by OhrR oxidation under aerobic conditions, which promoted OhrR dimerization and the activation of ohr. Furthermore, we showed that one of the two conserved cysteine residues in OhrR, Cys11, was critical for the sensitivity to organic hydroperoxides. Plant assays revealed that the inactivation of Ohr decreased the number of stem nodules and nitrogenase activity. Our data demonstrated that Ohr and OhrR are required for protecting A. caulinodans from organic hydroperoxide stress and play an important role in the interaction of the bacterium with plants. The results that were obtained in our study suggested that a thiol-based switch in A. caulinodans might sense host organic peroxide signals and enhance symbiosis.

Anisotropy and roughness of the solid-liquid interface of BCC Fe.

Melting point T m and kinetic coefficient µ (a proportional constant between the interfacial velocity ν and undercooling ΔT), along with the structural roughness of the solid-liquid interface for body centered cubic (BCC) Fe were calculated by molecular dynamics (MD) simulation. All simulations applied the Sutton-Chen potential, and adopted average bond orientational order (ABOO) parameters together with Voronoi polyhedron method to characterize atomic structure and calculate atomic volume. Anisotropy of T m was found through about 20~40 K decreasing from [100] to [110] and continuously to [111]. Anisotropy of µ with three low index orientations was found as: µ s,[100] > > µ s,[110] > µ s,[111] for solidifying process and µ m,[100] > > µ m,[111] > µ m,[110] for melting process. Slight asymmetry between melting and solidifying was discovered from that the ratios of µ m/µ s are all slightly larger than 1. To explain these, interfacial roughness R int and area ratio S/S 0 (ratio of realistic interfacial area S and the ideal flat cross-sectional area S 0) were defined to verify the anisotropy of interfacial roughness under different supercoolings/superheatings. The results indicated interfacial roughness anisotropies were approximately [100] > [111] > [110]; the interface in melting process is rougher than that in solidifying process; asymmetry of interfacial roughness was larger when temperature deviation ΔT was larger. Anisotropy and asymmetry of interfacial roughness fitted the case of kinetic coefficient µ very well, which could give some explanations to the anisotropies of T m and µ.

[Effects of hypoxia on the expression of heparanase and invasiveness of Hep-2 laryngeal carcinoma cell].

OBJECTIVE: To evaluate the effects of hypoxia on the expression of heparanase and the invasiveness of Hep-2 laryngeal carcinoma cell line. METHODS: Hep-2 cells were incubated at either normoxia (37 degrees C, 5% CO2, 20% O2) or hypoxia (37 degrees C, 5% CO2, 2% O2) condition for 6 h,12 h,24 h,36 h. Flow cytometry was used to detect the protein expression of heparanase under different hypoxia conditions. Fluorescence Index represents the relative content of heparanase protein. Cell invasiveness was measured by matrigel invasion assay. RESULTS: Compared with normoxia group, the heparanase protein expression level in 6 h hypoxia group was increased (P <0.05) and the heparanase protein expression levels in other hypoxia groups were significantly increased (P < 0.01). The heparanase protein expression level was increased (P < 0.05) among 6 h, 12 h, 24 h hypoxia groups; Compared with normoxia group, there was no significant change in the invasion cells at 6 h (P > 0.05) in hypoxia group; whereas the level of cell invasion was significantly increased in 12 h(P < 0.05), 24 h and 36 h groups (P < 0.01). During 6 to approximately 36 h hypoxia period, the increase of hypoxia-induced invasiveness in Hep-2 cell line show time-dependent manner. Meanwhile, there was a positive correlation between the expression of HPSE and the invasiveness of Hep-2 cells. CONCLUSION: Invasion of Hep-2 cells in hypoxia condition correlates with heparanase level. Hypoxia plays an important role in the augmentation of the heparanase expression and the invasiveness of human laryngeal carcinomas.