The Preparation and Performance of a New Polyurethane Vascular Prosthesis

We investigated the performance of small-caliber polyurethane (PU) small-diameter vascular prosthesis generated using the electrospinning technique. PU was electrospun into small-diameter, small-caliber tubular scaffolds for potential application as vascular grafts. We investigated the effects of electrospinning conditions (solution concentration, mandrel rotation speed) on the microstructure and porosity of the scaffolds for the purpose of preparing scaffolds with optimum microstructures and properties. We evaluated the mechanical properties of the scaffolds by tensile tests and the cytotoxicity of the PU small-diameter, small-caliber PU synthetic vascular graft by the MTT assay. The adhesion of endothelial cells to the PU scaffold was characterized by Hoechst staining and fluorescence microscopy, and we measured endothelial cell proliferation on the PU scaffold by the CCK-8 assay. We analyzed the prosthesis microstructure and endothelial cell morphology using scanning electron microscopy. With increasing PU concentration in the electrospinning solution, the fiber diameter of the vascular graft increased and the porosity decreased. In addition, with increasing electrospinning time, the wall thickness increased and the porosity decreased. We found that regular fiber orientation can be obtained by adjusting the rotation speed of the mandrel. Cell proliferation was not inhibited as the small-caliber PU synthetic vascular grafts showed little cytotoxicity. The endothelial cells had faster adherence to the PU scaffolds than to the PTFE surface during the initial contact. After prolonged cell culture, significantly higher endothelial cell proliferation rate was observed in the PU scaffold groups than the PTFE group. We obtained small-caliber PU vascular grafts with optimal fiber arrangement, excellent mechanical properties, and optimal biocompatibility by optimizing the electrospinning conditions. This study provides in vitro biocompatibility data that is helpful for the clinical application of the PU small-diameter, small-caliber PU vascular grafts.     

The Temporal Evolution of Anthropogenic Phosphorus Consumption in China and Its Environmental Implications

Modern human activities greatly disturb substance flows in nature and senselessly discard massive amounts of precious resources to natural waste reservoirs; phosphorus (P) is a good example of this. In this article, substance flow analysis is employed to quantify and explore the temporal evolution of China's P consumption in main metabolic nodes from 1984 to 2008, and then the environmental implications for P flows into both surface waters and natural soil are investigated. Results show that the metabolic nodes of human life and animal husbandry have demanded increasingly more P inputs, while disseminating more and more P wastes, with the waste recycling ratios of these processes dropping, respectively, from 65.9% and 66.1% in 1984 to 50.7% and 40.6% by 2008. These change traits were closely related to national polices including the Household Contract Responsibility System and the Shopping Basket Program, as well as the policy vacuum existing between China's agricultural and environmental administration departments. To achieve high crop yield, increasingly more inorganic P fertilizers have been utilized in China, but their use efficiency has decreased by 46.3%. From 2003 to 2008, the total P load into surface waters was stabilized at about 900.0 kilotons (kt), while the total P load into natural soil increased by more than 3.8 times to 3,131.3 kt P in 2008. City life and the intensive breeding of crops are identified as the main targets for further pollution control and nutrient recycling in China. Some suggestions for achieving environmentally sound practices and resource sustainability in China are proposed at the end of this article.     

Oxidative DNA and RNA damage and their prognostic values during Salmonella enteritidis-induced intestinal infection in rats

Abstract

Emerging evidence suggests that microbial pathogens may induce oxidative stress in infected hosts. The aim of the present study was to investigate the relationship between changes in oxidative stress and intestinal infection with and without antibiotic treatment in animal models. Sprague-Dawley (SD) rats were divided into three groups: rats infected with Salmonella enterica serovar Enteritidis (S. enteritidis), rats infected with S. enteritidis followed by norfloxacin treatment, and the control group. To evaluate oxidative stress changes, levels of 8-oxo-7,8-dihydroguanosine (8-oxo-Gsn) and 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxo-dGsn), which represented oxidative damage to RNA and DNA, respectively, were analysed in urine and tissue samples. In urine, the level of 8-oxo-Gsn increased significantly after oral exposure to S. enteritidis (p?≤?0.001) and returned to baseline after recovery. Notably, norfloxacin treatment decreased the level of 8-oxo-Gsn in urine significantly (p?=?0.001). Changes of 8-oxo-Gsn measured in tissues from the small intestine, colon, liver and spleen were consistent with 8-oxo-Gsn measured in urine. Our study suggested that 8-oxo-Gsn in urine may serve as a highly sensitive biomarker for evaluating the severity of S. enteritidis infection and the effectiveness of antibiotic treatment against infection.     

Hydrogen sulfide alleviates uranium-induced kidney cell apoptosis mediated by ER stress via 20S proteasome involving in Akt/GSK-3β/Fyn-Nrf2 signaling

Abstract

Hydrogen sulfide (H₂S) shows antioxidative, anti-inflammatory, antiapoptotic, and cytoprotective effects in kidneys. Recently, H₂S has been reported to alleviate uranium-induced rat nephrotoxicity through oxidative stress and inflammatory response via Nrf2-NF-κB pathways. Here, the protective effect and molecular mechanism of H₂S on uranium-induced apoptosis were examined in normal rat kidney proximal cells (NRK-52^E) in vitro. The results indicate that NaHS (an H₂S donor) administration in uranium-intoxicated kidney cells ameliorated uranium-induced reactive oxygen species generation, caspase-3-dependent apoptosis, and endoplasmic reticulum (ER) stress identified through several key markers including GRP78, C/EBP homologous protein (CHOP), and caspase-12. NaHS treatment in uranium-intoxicated kidney cells abolished the effects of uranium on Akt phosphorylation, GSK-3β activation, increased Fyn nuclear expression, and concomitantly decreased Nrf2 nuclear expression. NaHS administration in uranium-treated kidney cells resorted uranium-decreased the expression of two key subunit PSMA6 and PSMB7 in 20S proteasome. But, DRB (an Nrf2 inhibitor) administration abrogated the effects of NaHS on PSMA6 and PSMB7 expression in uranium-contaminated kidney cells. Bortezomib (a proteasome inhibitor) treatment in NaHS pulsing uranium cotreated kidney cells reversed the effects of NaHS on not only PSMA6 and PSMB7 but also GRP78 and CHOP. Taken together, all data suggest that H₂S can attenuate uranium-induced kidney cell apoptosis mediated by ER stress via 20S proteasome involving in Akt/GSK-3β/Fyn-Nrf2 signaling axis.     

Analysis of sequence patterns proximal to the stop codons in Oryza sativa

Abstract

A comprehensive analysis of sequence patterns around the stop codons was performed, by using more than 26,000 rice full-length cDNA sequences. Here it is shown that the bias was most outstanding at the position immediately before the stop codons (?1 codon), where the AAC codon was strongly preferred among ANC codons. Compared with other positions, the codon immediately after the stop codons (+1 codon) also displayed an apparent difference, and had a strong consensus for base A at the first, C at the second, and A at the third letters, respectively. Notably, the base biases at the positions directly downstream of the stop codons, such as the +4, +5 and +6 positions, were much stronger than other positions in the 3′-UTR region, suggesting that those base positions might act as an extended stop signal in the process of protein synthesis. Examination of the relationship between sequence pattern and gene expression level, assessed by CAI values and EST counting, revealed a tendency towards bigger base biases for highly expressed genes. It could be inferred that the translation stop signal is possibly involved in many sequence recognition elements other than the stop codons; highly expressed genes should hold strong sequence consensus around the stop codons for efficient translation termination.     

Comprehensive annotation of microRNA expression profiles

Background

MicroRNAs (miRNAs) regulate many biological processes by post-translational gene silencing. Analysis of miRNA expression profiles is a reliable method for investigating particular biological processes due to the stability of miRNA and the development of advanced sequencing methods. However, this approach is limited by the broad specificity of miRNAs, which may target several mRNAs.

Result

In this study, we developed a method for comprehensive annotation of miRNA array or deep sequencing data for investigation of cellular biological effects. Using this method, the specific pathways and biological processes involved in Alzheimer’s disease were predicted with high correlation in four independent samples. Furthermore, this method was validated for evaluation of cadmium telluride (CdTe) nanomaterial cytotoxicity. As a result, apoptosis pathways were selected as the top pathways associated with CdTe nanoparticle exposure, which is consistent with previous studies.

Conclusions

Our findings contribute to the validation of miRNA microarray or deep sequencing results for early diagnosis of disease and evaluation of the biological safety of new materials and drugs.

     

Delayed Treatment Effects of Xanthine Oxidase Inhibition on Systolic Overload-Induced Left Ventricular Hypertrophy and Dysfunction

The nonpurine selective xanthine oxidase (XO) inhibitor febuxostat attenuates development of left ventricular (LV) hypertrophy and dysfunction in mice when treatment is initiated within 1 hour of transverse aortic constriction (TAC). This study investigated whether a 7-day delay of treatment with the XO inhibitors febuxostat or allopurinol would reverse TAC-induced changes after onset of heart failure (HF). Neither treatment significantly affected TAC-induced LV hypertrophy; only febuxostat caused a modest improvement in LV function (～10% increase in LV ejection fraction). However, the purine analog allopurinol tended to increase mortality compared with vehicle or febuxostat in HF mice.     

Increased In Situ Intestinal Absorption of Phytoestrogenic Diarylheptanoids from Curcuma comosa in Nanoemulsions

Curcuma comosa has long been used as a gynecological medicine. Several diarylheptanoids have been purified from this plant, and their pharmacological effects were proven. However, there is no information about the absorption of C. comosa components to support the formulation usage. In the present study, C. comosa hexane extract and the mixture of its two major compounds, (4E,6E)-1,7-diphenylhepta-4,6-dien-3-ol (DA1) and (6E)-1,7-diphenylhept-6-en-3-ol (DA2), were formulated into nanoemulsions. The physical properties of the nanoemulsions and the in situ intestinal absorptions of DA1 and DA2 were evaluated. The results demonstrated the mean particle sizes at 0.207 ± 0.001 and 0.408 ± 0.014 μm, and the zeta potential at −14.57 ± 0.85 and −10.47 ± 0.32 mV for C. comosa nanoemulsion (C.c-Nano) and mixture of diarlylheptanoid nanoemulsions (DA-Nano), respectively. The entrapments of DA1 and DA2 were 76.61% and 75.41%, and 71.91% and 71.63% for C.c-Nano and DA-Nano, respectively. The drug loading ratios of DA1 and DA2 were 351.47 and 614.53 μg/mg, and 59.48 and 126.72 μg/mg for C.c-Nano and DA-Nano. The intestinal absorption rates of DA1 and DA2 were 0.329 ± 0.015 and 0.519 ± 0.026 μg/min/cm² in C.c-Nano, and 0.380 ± 0.006 and 0.428 ± 0.036 μg/min/cm² in DA-Nano, which were five to ten times faster than those in oil. In conclusion, the formulation in nanoemulsion forms obviously increased the intestinal absorption rate of diarylheptanoids.KEY WORDS: Curcuma comosa, diarylheptanoids, intestinal absorption, nanoemulsion, phytoestrogen     

A SAS-6-Like Protein Suggests that the Toxoplasma Conoid Complex Evolved from Flagellar Components

SAS-6 is required for centriole biogenesis in diverse eukaryotes. Here, we describe a novel family of SAS-6-like (SAS6L) proteins that share an N-terminal domain with SAS-6 but lack coiled-coil tails. SAS6L proteins are found in a subset of eukaryotes that contain SAS-6, including diverse protozoa and green algae. In the apicomplexan parasite Toxoplasma gondii, SAS-6 localizes to the centriole but SAS6L is found above the conoid, an enigmatic tubulin-containing structure found at the apex of a subset of alveolate organisms. Loss of SAS6L causes reduced fitness in Toxoplasma. The Trypanosoma brucei homolog of SAS6L localizes to the basal-plate region, the site in the axoneme where the central-pair microtubules are nucleated. When endogenous SAS6L is overexpressed in Toxoplasma tachyzoites or Trypanosoma trypomastigotes, it forms prominent filaments that extend through the cell cytoplasm, indicating that it retains a capacity to form higher-order structures despite lacking a coiled-coil domain. We conclude that although SAS6L proteins share a conserved domain with SAS-6, they are a functionally distinct family that predates the last common ancestor of eukaryotes. Moreover, the distinct localization of the SAS6L protein in Trypanosoma and Toxoplasma adds weight to the hypothesis that the conoid complex evolved from flagellar components.