Nanomaterial-based Therapeutics for Biofilm-generated Bacterial Infections / 生物化学与生物物理进展

Bacterial biofilms gave rise to persistent infections and multi-organ failure, thereby posing a serious threat to human health. Biofilms were formed by cross-linking of hydrophobic extracellular polymeric substances (EPS), such as proteins, polysaccharides, and eDNA, which were synthesized by bacteria themselves after adhesion and colonization on biological surfaces. They had the characteristics of dense structure, high adhesiveness and low drug permeability, and had been found in many human organs or tissues, such as the brain, heart, liver, spleen, lungs, kidneys, gastrointestinal tract, and skeleton. By releasing pro-inflammatory bacterial metabolites including endotoxins, exotoxins and interleukin, biofilms stimulated the body’s immune system to secrete inflammatory factors. These factors triggered local inflammation and chronic infections. Those were the key reason for the failure of traditional clinical drug therapy for infectious diseases.In order to cope with the increasingly severe drug-resistant infections, it was urgent to develop new therapeutic strategies for bacterial-biofilm eradication and anti-bacterial infections. Based on the nanoscale structure and biocompatible activity, nanobiomaterials had the advantages of specific targeting, intelligent delivery, high drug loading and low toxicity, which could realize efficient intervention and precise treatment of drug-resistant bacterial biofilms. This paper highlighted multiple strategies of biofilms eradication based on nanobiomaterials. For example, nanobiomaterials combined with EPS degrading enzymes could be used for targeted hydrolysis of bacterial biofilms, and effectively increased the drug enrichment within biofilms. By loading quorum sensing inhibitors, nanotechnology was also an effective strategy for eradicating bacterial biofilms and recovering the infectious symptoms. Nanobiomaterials could intervene the bacterial metabolism and break the bacterial survival homeostasis by blocking the uptake of nutrients. Moreover, energy-driven micro-nano robotics had shown excellent performance in active delivery and biofilm eradication. Micro-nano robots could penetrate physiological barriers by exogenous or endogenous driving modes such as by biological or chemical methods, ultrasound, and magnetic field, and deliver drugs to the infection sites accurately. Achieving this using conventional drugs was difficult. Overall, the paper described the biological properties and drug-resistant molecular mechanisms of bacterial biofilms, and highlighted therapeutic strategies from different perspectives by nanobiomaterials, such as dispersing bacterial mature biofilms, blocking quorum sensing, inhibiting bacterial metabolism, and energy driving penetration. In addition, we presented the key challenges still faced by nanobiomaterials in combating bacterial biofilm infections. Firstly, the dense structure of EPS caused biofilms spatial heterogeneity and metabolic heterogeneity, which created exacting requirements for the design, construction and preparation process of nanobiomaterials. Secondly, biofilm disruption carried the risk of spread and infection the pathogenic bacteria, which might lead to other infections. Finally, we emphasized the role of nanobiomaterials in the development trends and translational prospects in biofilm treatment.

Location Analysis of Volatile Oil in Angelicae Sinensis Radix by Frozen Section and Fluorescence Imaging / 中国实验方剂学杂志

ObjectiveTo establish a simple， fast and accurate method for locating the volatile oil in Angelicae Sinensis Radix based on frozen section and fluorescence imaging technology， and to reveal the distribution and accumulation of volatile oil in the roots of this herbal medicine. MethodAngelicae Sinensis Radix was used as the research material， the best frozen section conditions for the research material were established by comparing the effects of different cryoprotectants on the quality of frozen sections of Angelicae Sinensis Radix. The suitability of Sudan Ⅲ chemical staining and fluorescence localization for positioning the volatile oil were compared according to the loss of volatile oil and the complexity of operation process. ResultA new method for evaluating the quality of frozen sections of Angelicae Sinensis Radix was established. According to the evaluation equation， it was found that the highest score was obtained when the head， body and tail positions of Angelicae Sinensis Radix were treated with 20% glycerol， 15% glycerol and 20% sucrose， respectively. There was yellowish-brown oily substance in the oil chambers of phelloderm and secondary phloem， and oil canal of the secondary xylem of Angelicae Sinensis Radix， which could be stained orange red or orange yellow by Sudan Ⅲ， and there was green spontaneous fluorescence in the same part under the fluorescence microscope. ConclusionThe relatively complete section of Angelicae Sinensis Radix can be obtained after being treated with cryoprotectant. The volatile oil exists in the oil chambers of phelloderm and secondary phloem， and oil canal of the secondary xylem of Angelicae Sinensis Radix. This study can provide reference for observation of the accumulation sites of volatile oil in other plants.

PreoperativePredictionoftheExpressionofCK19inHepatocellularCarcinomaby Gd-EOB-DTPAEnhancedMRI / 中山大学学报(医学科学版)

@#【Objective】 To investigate the predictive value of preoperative Gd- EOB- DTPA enhanced MRI in the expression of cytokeratin 19（CK19）in hepatocellular carcinoma（HCC）.【Methods】A total of 102 patients，including 94 male and 8 female，with single HCC confirmed by pathology after operation who underwent preoperative enhanced MRI were retrospectively analyzed. A total of 25 were CK19-positive HCC and 77 were CK19-negative HCC. Two radiologists evaluated MR features including tumor size，tumor margin，intratumoral vessels，signal intensity（SI）on arterial phase （AP） ，enhancement pattern ，arterial rim enhancement ，peritumoral enhancement ，internal cystic or necrotic portion，hemorrhage，intratumoral fat，tumor capsule，vascular invasion，lymph node metastasis，intratumoral septum， target sign on diffusion weighted imaging（DWI）or hepatobiliary phase（HBP），peritumor hypointensity，SI on ADC，SI on HBP ，T1 relaxation times and T1 reduction rate between pre- and post- contrast enhancement. The associations between these imaging features and CK19 expression were investigated. 【Results】SI on AP（P = 0.013），arterial rim enhancement（P = 0.018），target sign on DWI（P = 0.001）and target sign on HBP（P = 0.005）were significantly associated with CK19 expression. Delayed enhanced intratumoral septum（P = 0.042）was associated with CK19 expression between HCCs less than 5 cm. Target sign on DWI（P = 0.001，OR = 4.875，95%CI：1.838~12.927）were independent significant factors of CK19- positive HCC.【Conclusion】Preoperative enhanced MRI with Gd- EOB- DTPA is helpful to predict CK19 expression of HCC.

Reward information encoded by power of local field potentials in the primate prefrontal cortex and striatum / 生理学报

Prefrontal cortex and striatum are two major areas in the brain. Some research reports suggest that both areas are involved in many advanced cognitive processes, such as learning and memory, reward processing, and behavioral decision. Single-unit recording experiments have found that neurons in the prefrontal cortex and striatum can represent reward information, but it remains elusive whether and how local field potentials (LFPs) in the two areas encode reward information. To investigate these issues, we recorded LFPs simultaneously in the prefrontal cortex and striatum of two monkeys by performing a reward prediction task (a large amount reward vs a small amount reward). Recorded LFP signals were transformed from the time domain to the time and frequency domain using the method of short-time Fourier transform (STFT). We calculated the power in each frequency and time, and examined whether they were different in the two reward conditions. The results showed that power of LFPs in both the prefrontal cortex and striatum distinguished one reward condition from the other one. And the power in small reward trials was greater than that in large reward trials. Furthermore, it was found that the LFPs better encoded reward information in the beta band (14-30 Hz) rather than other frequency bands. Our results suggest that the LFPs in the prefrontal cortex and striatum effectively represent reward information, which would help to further understand functional roles of LFPs in reward processing.

Reconstruction of a digital three-dimensional model of fetal heart / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the methods for constructing the digital three-dimensional model of fetal heart.</p><p><b>METHODS</b>Original two-dimensional CT image data sets were collected from 4 abortion fetuses with fetal malformations but not heart malformation or chromosomal abnormalities. The three-dimensional fetal heart model was reconstructed using Mimics14.0 software.</p><p><b>RESULTS</b>In the reconstructed three-dimensional fetal heart, the left atrium, left ventricle, right atrium, right ventricle, the ascending aorta, the main pulmonary and their branches, the superior cava and inferior vena cava were marked with different colors, and these structures could be displayed individually or with other structures. This model also allowed three-dimensional arbitrary scaling, shifting or rotation at any angle, and the diameter of the each vessel could be measured with the software.</p><p><b>CONCLUSION</b>The fetal heart model can be successfully reconstructed from the CT datasets using three-dimensional reconstruction software to facilitate clinical and anatomical teaching.</p>

Effect of hydrogen sulfide on H₂O₂-stimulated primary neonatal rat cardiomyocytes / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of hydrogen sulfide (H2S) on H2O2-stimulated primary neonatal rat cardiomyocytes and related mechanism.</p><p><b>METHODS</b>Primary neonatal rat cardiomyocytes were treated with various concentrations of H2O2 (10, 100, 1000 µmol/L) for 24 h to establish the oxidative stress-induced cell injury model after 3 days' conventional culture. In addition, different concentrations of NaHS (1, 10, 100 µmol/L) were added to cardiomyocytes in the absence and presence of 100 µmol/L H2O2 for 24 h. The viability of cardiomyocytes was measured by MTT assay. The SOD vitality was measured by xanthine oxidase method and MDA content was determined by thiobarbituric acid colorimetric method. LDH activity was measured by chemical colorimetric method. The percentage of apoptotic cells was assessed by flow cytometry (FCM). The mitochondrial membrane potential (MMP) was analyzed by rhodamine 123 (Rh123) staining and photofluorography. The level of reactive oxygen species (ROS) in cardiomyocytes was measured by DCFH-DA staining and photofluorography.</p><p><b>RESULTS</b>Cell viability and SOD vitality were significantly reduced while MDA content and LDH activity were significantly increased with increasing H2O2 concentrations. These effects could be partly reduced by cotreatment with H2O2 in a concentration-dependent manner (all P < 0.05). Compared with control group, the DCF fluorescence intensity significantly increased in the 100 µmol/L H2O2 group (P = 0.003), which could be attenuated by NaHS in a dose-dependent manner. Compared with control group, the MMP significantly decreased in the 100 µmol/L H2O2 group (P = 0.000), which could be partly reversed by cotreatment with NaHS in a dose-dependent manner. Moreover, H2O2 treatment also significantly reduced 100 µmol/L H2O2 induced apoptosis in a dose-dependent manner.</p><p><b>CONCLUSION</b>H2S protects primary neonatal rat cardiomyocytes against H2O2-induced oxidative stress injury through inhibition of H2O2 induced overproduction of ROS, dissipation of MMP and apoptosis.</p>

Down-regulated Pygo2 expression suppresses proliferation, invasion, and cyclin D1 expression of glioblastoma U251 cells / 第二军医大学学报

Objective: To construct recombinant vectors for RNA interference(RNAi) targeting Pygo2, and to assess its influence on the proliferation, invasion of glioblastoma U251 cells and the related mechanism. Methods: A pair of oligonucleotides containing short hairpin structure targeting Pygo2 cDNA sequences were designed and synthesized, and their negative control sequences were also synthesized. After annealed, they were inserted into pSuper vector to generate the recombinant plasmids. Then the recombinant plasmids were digested with EcoR I and Hind III for identification, and the sequence was assayed by DNA sequencing. The recombinant plasmids were transfected into cultured glioblastoma U251 cells using Lipofectamine™ 2000. The effect of Pygo2 shRNA on Pygo2 mRNA and protein in U251 cells was detected by real-time PCR and Western blotting analysis, respectively. MTT assay was used to detect the cell proliferation; cell cycle was analyzed by flow cytometry; Bromodeoxyuridine (BrdU) incorporation analysis was used to examine DNA synthesis; and cell invasion assay was performed using Transwell chambers. The effect of Pygo2 shRNA on the protein level and subcellular location of cyclin D1 and β-catenin was detected by Western blotting analysis and immunofluorescent staining. Results: The recombinant plasmids were completely coincided with the design by the restriction map and the sequence analysis. Pygo2 mRNA and protein expression was significantly suppressed by Pygo2 shRNA. Furthermore, the proliferation of cells in Pygo2 shRNA group was notably inhibited, cell cycle was arrested at the G1 phase, and BrdU incorporation and migrating cells were significantly inhibited. In addition, Pygo2 knockdown significantly down-regulated cyclin D1 expression without altering the subcellular location, and the expression level and subcellular location of β-catenin had no noticeable changes. Conclusion: The recombinant vectors for specific suppression of Pygo2 expression have been constructed successfully. Inhibition of Pygo2 expression can suppress cell proliferation and invasion of glioma U251 cells, decrease DNA synthesis, arrest cell cycle at the G1 phase, and decrease expression of the Wnt target gene cyclin Dl.

Influence of silencing hypoxia-inducible factor-1α gene on proliferation, invasion and metastasis of glioblastoma U87 cells / 中华神经医学杂志

Objective To observe the influence of silencing hypoxia-inducible factor-1α(HIF-1α)gene on the proliferation, invasion and metastasis of glioblastoma U87 cells. Methods The samples were divided into 3 groups: blank group: samples without giving any treatments, control group: cells with empty shRNA vector, and experimental group: cells with HIF-1α-shRNA transfection complex. HIF-1α gene was silenced by shRNA constructed in early time; and HIF-1α-shRNA lentivirus vector was constructed in the experimental group, and then transfected into glioblastoma U87 cells with the mediation of liposome. The interference efficiency was detected by using RT-PCR and Western blotting, and cell proliferation was measured by MTT assay; cell migration in vitro was observed by migration test, and invasion and metastasis abilities were detected by Transwell booth model. Results As compared with those in cells of the control and blank groups, the mRNA and protein expressions of HIF-1α in cells of the experimental group were significantly decreased; MTT assay showed that the cell proliferation in the experimental group was significantly lower than that in the other 2 groups (P<0.05). The number of penetrating cells of the blank group, control group and experimental group in Transwell chamber invasion assay were (125.2±10.8), (118.3±8.3), (60.9±5.4), respectively, and significant differences were noted between each 2 groups (P<0.05). Conclusion The mRNA and protein levels of HIF-1α in U87 cells are efficiently depressed by HIF-1α-shRNA, and so are the proliferation, invasion and metastasis abilities of U87 cells.

Effect on expression of mice alpha-hemoglobin stabilizing protein in different developmental stages treated with Yisui Shengxue granules / 中国中药杂志

<p><b>OBJECTIVE</b>To discuss the effect of Yisui Shengxue granules on expression of alpha-hemoglobin stabilizing protein (AHSP) mRNA in different developmental stages mice.</p><p><b>METHOD</b>The total RNAs were extracted from the bone marrow karyocyte of normal adult mice and the karyocyte of fetus liver and fetus spleen in pregnanted mice (pregnanted 21 days) and fetal mice (pregnanted 14 days). The expression level of AHSP mRNA in different developmental stages mice interfered with Yisui Shengxue granules was measured by real-time PCR.</p><p><b>RESULT</b>The intervention of Yisui Shengxue granules could significantly up-regulated the expression levels of AHSP mRNA in normal adult mice.</p><p><b>CONCLUSION</b>The result revealed that one of possible molecular mechanism of the effects caused by Yisui Shengxue granules is that it can promote the AHSP gene expression, reduce the free a-globin deposit, then prevent the poison to erythrocyte and decrease the haemolysis.</p>