Establishment and assessment of a preclinical model of acute kidney injury induced by contrast media combined acute myocardial ischemia reperfusion surgery.

Acute kidney injury (AKI) is a common complication after acute myocardial infarction (AMI) in clinical practice, and the majority of previous preclinical models were induced by a single factor. The objective of the present study was to establish a stable preclinic model of AKI induced by contrast media (CM) with acute myocardial ischemia reperfusion surgery and to identify the effect of oxidative stress on kidney injury. Rats were treated individually or with CM or myocardial ischemia reperfusion surgery. Renal baseline and AKI parameters, the level of oxidative stress and histopathological images were examined along with AKI biomarkers. Results showed the incidence of AKI in the CM group and ischemia reperfusion injury (IRI) group was 40%, χ2 test (P<0.05 vs. CM-IRI) and 35%, χ2 test (P<0.05 vs. CM-IRI) and the combination group had the highest incidence rate 75%. IRI surgery combined with CM diminished kidney function and induced oxidative stress by increasing creatinine, blood urea nitrogen and reactive oxygen species levels. Western blotting showed that the early AKI biomarker of NGAL and KIM-1 increased and that the combination group had the highest value. Pathology damage exhibited severe kidney damage in the combination group compared with other control groups. The present research established a reliable preclinic model of post-AMI AKI with a stable and high postoperative AKI rate. Additionally, CM was demonstrated to exacerbate AKI caused by acute myocardial infarction through oxidative stress and, thus, oxidative stress may be a potential therapeutic target.

Hamiltonian replica exchange simulations of glucose oxidase adsorption on charged surfaces.

The Hamiltonian replica exchange Monte Carlo (H-REMC) algorithm was applied to study protein adsorption and its performance was compared with that of the temperature replica exchange Monte Carlo (T-REMC). Comparisons indicate that the simulation results are consistent but the computational efficiency is improved for H-REMC. H-REMC could accurately and efficiently identify the preferred orientations of glucose oxidase (GOx) on charged surfaces; different preferential GOx orientations on different surfaces and solution conditions could be spotted with a much fewer number of simulation runs. On positively charged surfaces, when electrostatic interactions dominate, the negatively charged GOx can be easily adsorbed with the "standing" orientation for which the substrate-binding domain is accessible to substrates. As the surface charge densities decrease and ionic strengths increase, there is an increasing contribution from the van der Waals (vdW) interactions, and thus more possible orientations appear. When the vdW interactions dominate, the unfavorable "front-lying" becomes the preferred orientation for which the substrate-binding domain is blocked by the surface. On negatively charged surfaces, though GOx has a net charge of -30 e under physiological conditions, the charged groups are unevenly distributed over the protein surface; the positive potential regions in the "back" of GOx enable the protein to be adsorbed on negatively charged surfaces with the "back-lying" orientation. The H-REMC provides an alternative method to accurately and efficiently probe the lowest-energy orientation of proteins adsorbed on surfaces for biotechnological applications.

Quantitative assessment of soil productivity and predicted impacts of water erosion in the black soil region of northeastern China.

As Northeastern China is the country's most significant grain production base, soil productivity in this region has consistently attracted attention. National food security is threatened by an ongoing drain of soil nutrients and decline in soil productivity. Black soil is the key natural resource in this region of China, which is thus known as the "black soil region". It is necessary to study the impact of soil erosion on black soil and its productivity to protect this important resource and ensure its sustainable productivity. Through a field investigation and laboratory analysis, the physicochemical properties in 112 soil profiles from a typical black soil sub-region were measured to assess soil productivity using a soil productivity index (PI) model. The soil PI in the study area was relatively high and showed an increasing trend from southwest to northeast. PI values and their spatial distribution were affected by soil organic matter, soil clay content, soil thickness, slope and geomorphological position. Soil productivity and cluster analysis revealed that the southern and northwestern areas of the typical black soil sub-region under study were subject to the greatest risk. To maintain the region's soil productivity, it is vital to prevent the black soil layer, especially the topsoil, from being destroyed.

Dependence of credit spread and macro-conditions based on an alterable structure model.

The fat-tail financial data and cyclical financial market makes it difficult for the fixed structure model based on Gaussian distribution to characterize the dynamics of corporate bonds spreads. Using a flexible structure model based on generalized error distribution, this paper focuses on the impact of macro-level factors on the spreads of corporate bonds in China. It is found that in China's corporate bonds market, macroeconomic conditions have obvious structural transformational effects on bonds spreads, and their structural features remain stable with the downgrade of bonds ratings. The impact of macroeconomic conditions on spreads is significant for different structures, and the differences between the structures increase as ratings decline. For different structures, the persistent characteristics of bonds spreads are obviously stronger than those of recursive ones, which suggest an obvious speculation in bonds market. It is also found that the structure switching of bonds with different ratings is not synchronous, which indicates the shift of investment between different grades of bonds.

A randomized open-labeled study to demonstrate the non-inferiority of purified chick-embryo cell rabies vaccine administered in the Zagreb regimen (2-1-1) compared with the Essen regimen in Chinese adults.

The Zagreb regimen has been used for 20 years in various countries. In China, until 2010, the Zagreb schedule was only approved for purified chick embryo cell vaccine (PCECV) and purified Vero cell rabies vaccines (PVRV). In this phase III clinical trial, we aimed to demonstrate the safety and immunogenic non-inferiority of the Zagreb regimen compared with the Essen regimen in healthy adult Chinese immunized with PCECV (Rabipur®). The study enrolled 825 subjects aged 18 to 50 years; serum samples were collected on Days 0, 7, 14, 42, and at 13 months to assess rabies virus neutralizing antibody (RVNA) concentrations. Solicited and unsolicited local and systemic reactions were recorded for 6 days following the day of vaccination, and collected throughout the entire study period (Day 1 until Month 13). The Zagreb regimen was non-inferior to the Essen regimen with regard to RVNA concentrations after 7, 14, and 42 days, and 13 months of immunization. The non-inferiority of seroconversion was established at Days 14 and 42. The incidence of local and systemic reactions was similar between groups, and mostly of mild or moderate severity. Vaccine-related adverse events occurred more frequently in the Essen group than in the Zagreb group. Vaccination with PCECV under a 2-1-1 regimen is as safe and immunogenic as under the traditional 5-dose Essen regimen for rabies post-exposure prophylaxis, and is a more cost-effective option, has a more practical vaccination schedule, and can potentially increase compliance.

[Morphology-based criteria for ultrasonic assessment of axillary lymph node status in primary breast cancer].

OBJECTIVE: To evaluate the morphology-based criteria for the ultrasonic assessment of axillary lymph node in primary breast cancer. METHODS: A total of 2256 T0-2N0 patients underwent axillary ultrasound preoperatively. Lymph nodes were classified as normal if no node was found or cortex thickness was even and < 3 mm; abnormal, (1) if cortex thickness was even but ≥ 3 mm or (2) focally thickened cortex ≥ 3 mm or (3) fatty hilum was absent. The patients in the abnormal group underwent ultrasound guided fine-needle aspiration (US-FNA). Except for positive lymph nodes, all the others underwent sentinel lymph node biopsy (SLNB). RESULTS: In this series, 692 (30.7%) were pathologically confirmed positive LNs. Among them, 214 (9.5%) were identified by US-FNA. And 361 were abnormal according to the above mentioned criteria. The proportions were 11.6%, 54.8% and 33.5% in Group 1-3 respectively. The sensitivity, specificity, positive and negative predictive values of these criteria alone were 35.8%, 92.8%, 68.7% and 76.6% respectively. CONCLUSION: The present morphology-based criteria for the ultrasonic assessment of lymph node status is both effective and practical in primary breast cancer.

[Diagnostic value and health economic evaluation of ultrasound-combined fine-needle aspiration cytology in primary breast cancer].

OBJECTIVE: To explore the diagnostic value and health economic evaluation of ultrasound-combined fine-needle aspiration cytology for axillary lymph node status in breast cancer. METHODS: We reviewed retrospectively collected the data from 2503 cases of biopsy-proved breast cancer (T0-2) at our breast center between May 2005 and June 2010. The diagnostic fees of ultrasound-combined fine-needle aspiration cytology and clinical examination were calculated and assessed with cost-minimization analysis. RESULTS: Ultrasound-combined fine-needle aspiration cytology prevented 10.9 percent of the patients with positive clinical findings from unnecessary sentinel lymph node biopsy and achieved a saving of 155.55 RMB per patient. However, only 29.4 percent of the cases were diagnosed with ultrasonographic abnormal axillary nodes. CONCLUSIONS: Ultrasound-combined fine-needle aspiration cytology has great application values. The ultrasonic diagnostic criteria of abnormal axillary nodes should be loosened.

Parallel tempering Monte Carlo simulations of lysozyme orientation on charged surfaces.

In this work, the parallel tempering Monte Carlo (PTMC) algorithm is applied to accurately and efficiently identify the global-minimum-energy orientation of a protein adsorbed on a surface in a single simulation. When applying the PTMC method to simulate lysozyme orientation on charged surfaces, it is found that lysozyme could easily be adsorbed on negatively charged surfaces with "side-on" and "back-on" orientations. When driven by dominant electrostatic interactions, lysozyme tends to be adsorbed on negatively charged surfaces with the side-on orientation for which the active site of lysozyme faces sideways. The side-on orientation agrees well with the experimental results where the adsorbed orientation of lysozyme is determined by electrostatic interactions. As the contribution from van der Waals interactions gradually dominates, the back-on orientation becomes the preferred one. For this orientation, the active site of lysozyme faces outward, which conforms to the experimental results where the orientation of adsorbed lysozyme is co-determined by electrostatic interactions and van der Waals interactions. It is also found that despite of its net positive charge, lysozyme could be adsorbed on positively charged surfaces with both "end-on" and back-on orientations owing to the nonuniform charge distribution over lysozyme surface and the screening effect from ions in solution. The PTMC simulation method provides a way to determine the preferred orientation of proteins on surfaces for biosensor and biomaterial applications.