To investigate the efficacy of fosfomycin against extended-spectrum Beta-lactamases (ESBL) producing Escherichia coli in Taiwan and the resistance mechanisms and characterization of human and pig ...isolates, we analyzed 145 ESBL-producing isolates collected from two hospitals (n = 123) and five farms (n = 22) in Taiwan from February to May, 2013. Antimicrobial susceptibilities were determined. Clonal relatedness was determined by PFGE and multi-locus sequence typing. ESBLs, ampC, and fosfomycin resistant genes were detected by PCR, and their flanking regions were determined by PCR mapping and sequencing. The fosfomycin resistant mechanisms, including modification of the antibiotic target (MurA), functionless transporters (GlpT and UhpT) and their regulating genes such as uhpA, cyaA, and ptsI, and antibiotic inactivation by enzymes (FosA and FosC), were examined. The size and replicon type of plasmids carrying fosfomycin resistant genes were analyzed. Our results revealed the susceptibility rates of fosfomycin were 94% for human ESBL-producing E. coli isolates and 77% for pig isolates. The PFGE analysis revealed 79 pulsotypes. No pulsotype was found existing in both human and pig isolates. Three pulsotypes were distributed among isolates from two hospitals. ISEcp1 carrying blaCTX-M-group 9 was the predominant transposable elements of the ESBL genes. Among the thirteen fosfomycin resistant isolates, functionless transporters were identified in 9 isolates. Three isolates contained novel amino acid substitutions (Asn67Ile, Phe151Ser and Trp164Ser, Val146Ala and His159Tyr, respectively) in MurA (the target of fosfomycin). Four isolates had fosfomycin modified enzyme (fosA3) in their plasmids. The fosA3 gene was harboured in an IncN-type plasmid (101 kbp) in the three pig isolates and an IncB/O-type plasmid (113 kbp) in the human isolate. In conclusion, we identified that 6% and 23% of the ESBL-producing E. coli from human and pigs were resistant to fosfomycin, respectively, in Taiwan. No clonal spread was found between human and pig isolates. Functionless transporters were the major cause of fosfomycin resistance, and the fosA3-transferring plasmid between isolates warrants further monitoring.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this paper, the authors' aim was to use CT perfusion imaging to evaluate the early changes in tumor microcirculation following radiosurgery in rat C6 brain gliomas.
C6 glioma cells were inoculated ...into the right caudate nucleus of 25 Wistar rats using a stereotactic procedure. Tumor-bearing rats were randomly divided into 2 groups (tumor group and treatment group). Rats in the treatment group received maximal doses of 20 Gy delivered by the X-knife unit 16 days postimplantation. Computed tomography perfusion imaging was performed in all rats 3 weeks after tumor implantation prior to death and histopathological analysis.
Hypocellular regions and tumor edema were increased in the treatment group compared with the tumor group. Parameters of CT perfusion imaging including cerebral blood volume (CBV) and mean transit time (MTT) of the tumors as well as the permeability surface area (PSA) product in the tumor-brain districts were decreased in the treatment group compared with the tumor group (p < 0.05). Although microvascular density (MVD) in the periphery of the tumors in the treatment group was higher than that in the normal contralateral brain (p < 0.05), MVD of the tumors in the treatment group was less than that in the tumor group (p < 0.01). There was a positive correlation between cerebral blood flow (CBF) and MVD as well as CBV and MVD in the center and periphery of tumors in both groups (p < 0.05).
A decrease in the perfusion volume of rat C6 brain gliomas was observed during the acute stage following X-knife treatment, and CBF and CBV were positively correlated with MVD of rat C6 brain gliomas. Thus, CT perfusion imaging can be used to evaluate the early changes in tumor microcirculation following radiosurgery.
The silicon-boron(Si-B) pitch was successfully synthesized by solution-thermal treatment method using coal pitch, polycarbosilane and borane pyridine as starting materials. The B-Si pitch ...carbonization product was attained by carbonization in the temperature 900degreesC under flowing argon. The Si-B pitch prepared and its carbonization product were characterized by SEM, FT-IR, TG-DSC and XRD. The results show that the carbonization product has C-Si and C-B bonds and the silicon and boron components of the product is still amorphous when it is treated at 900degreesC. The weight loss of the Si-B pitch carbonization product at 900degreesC for 12h in air atmosphere is only 3.76wt%. The weight loss of the product is less than 4 wt% when the oxidation temperature reaches 1180degreesC. The prepared B-Si pitch carbonization product possesses good anti-oxidation property at high temperature in air atmosphere.
The continuing threat of dengue fever necessitates a comprehensive characterisation of its epidemiological trends. Phylogenetic and recombination events were reconstructed based on 100 worldwide ...dengue virus (DENV) type 1 genome sequences with an outgroup (prototypes of DENV2-4). The phylodynamic characteristics and site-specific variation were then analysed using data without the outgroup. Five genotypes (GI-GV) and a ladder-like structure with short terminal branch topology were observed in this study. Apparently, the transmission of DENV1 was geographically random before gradual localising with human activity as GI-GIII in South Asia, GIV in the South Pacific, and GV in the Americas. Genotypes IV and V have recently shown higher population densities compared to older genotypes. All codon regions and all tree branches were skewed toward a negative selection, which indicated that their variation was restricted by protein function. Notably, multi-epistatic interaction sites were found in both PrM 221 and NS3 1730. Recombination events accumulated in regions E, NS3-NS4A, and particularly in region NS5. The estimated coevolution pattern also highlights the need for further study of the biological role of protein PrM 221 and NS3 1730. The recent transmission of emergent GV sublineages into Central America and Europe mandates closely monitoring of genotype interaction and succession.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
AIM：To investigate the effect and mechanism of oridonin on the gastric cancer cell line HGC-27 in vitro.METHODS：The inhibitory effect of oridonin on HGC-27 cells was detected using the ...3-（4,5-dimethylthiazol2-yl）-2,5-diphenyl tetrazolium bromide assay.After treatment with 10 μg/mL oridonin for 24 h and 48 h,the cells were stained with acridine orange/ethidium bromide.The morphologic changes were observed under an inverted fluorescence microscope.DNA fragmen-tation（a hallmark of apoptosis） and lactate dehydrogenase activity were examined using DNA ladder assay and lactate dehydrogenase-release assay.After treated with oridonin（0,1.25,2.5,5 and 10 μg/mL）,HGC-27 cells were collected for anexin V-phycoerythrin and 7-amino-actinomycin D double staining and tested by flow cytometric analysis,and oridonin-induced apoptosis in HGC-27 cells was detected.After treatment with oridonin for 24 h,the effects of oridonin on expression of Apaf-1,Bcl-2,Bax,caspase-3 and cytochrome c were also analyzed using reverse-transcript polymerase chain reaction（RT-PCR） and Western blotting.RESULTS：Oridonin significantly inhibited the proliferation of HGC-27 cells in a dose-and time-dependent manner.The inhibition rates of HGC-27 treated with four different concentrations of oridonin for 24 h（1.25,2.5,5 and 10 μg/mL） were 1.78% ± 0.36%,4.96% ± 1.59%,10.35% ± 2.76% and 41.6% ± 4.29%,respectively,which showed a significant difference（P 〈 0.05）.The inhibition rates of HGC-27 treated with oridonin at the four concentrations for 48 h were 14.77% ± 4.21%,21.57% ± 3.75%,30.31% ± 4.91% and 61.19% ± 5.81%,with a significant difference（P 〈 0.05）.The inhibition rates of HGC-27 treated with oridonin for 72 h at the four concentrations were 25.77% ± 4.85%,31.86% ± 3.86%,48.30% ± 4.16% and 81.80% ± 6.72%,with a significant difference（P 〈 0.05）.Cells treated with oridonin showed typical apoptotic features with acridine orange/ethidium bromide staining.After treatment with oridonin,the cells became round,shrank,and developed small buds around the nuclear membrane while forming apoptotic bodies.Lactate dehydrogenase（LDH） release assay showed that after treated with 1.25 μg/mL and 20 μg/mL oridonin for 24 h,LDH release of HGC-27 caused by apoptosis increased from 22.94% ± 3.8% to 52.68% ± 2.4%（P 〈 0.001）.However,the change in the release of LDH caused by necrosis was insignificant,suggesting thatthe major cause of oridonin-induced HGC-27 cell death was apoptosis.Flow cytometric analysis also revealed that oridonin induced significant apoptosis compared with the controls（P 〈 0.05）.And the apoptosis rates of HGC-27 induced by the four different concentrations of oridonin were 5.3% ± 1.02%,12.8% ± 2.53%,28.5% ± 4.23% and 49.6% ± 3.76%,which were in a dose-dependent manner（P 〈 0.05）.After treatment for 24 h,DNA ladder showed that oridonin induced a significant increase in DNA fragmentation in a dosedependent manner.RT-PCR revealed that mRNA expression levels were up-regulated compared with the controls in caspase-3（0.917 ± 0.103 vs 0.357 ± 0.019,P 〈 0.05）,cytochrome c（1.429 ± 0.111 vs 1.002 ± 0.014,P 〈 0.05）,Apaf-1（0.688 ± 0.101 vs 0.242 ± 0.037,P 〈 0.05） and Bax（0.856 ± 0.101 vs 0.278 ± 0.027,P 〈 0.05）（P 〈 0.05）,whereas down-regulated in Bcl-2（0.085 ± 0.012 vs 0.175 ± 0.030,P 〈 0.05）.Western blotting analysis also confirmed this result.CONCLUSION：Apoptosis of HGC-27 induced by oridonin may be associated with differential expression of Apaf-1,caspase-3 and cytochrome c,which are highly dependent upon the mitochondrial pathway.
Three kinds of pitches were used as matrix precursors, the self-fabricated mesophase (AR) pitch-based carbon fibers were used as the reinforcing agent, one dimension (ID) carbon/carbon (C/C) ...composites were prepared by a hot-pressing molding method at about 500degreesC and subsequent carbonization as well as graphitization treatments. The influence of precursor pitches and heat-treatment temperatures (HTTs) on the thermal conductive properties of the C/C composites were investigated. The morphology and microstructure of graphitized C/C composites were characterized by scanning electron microscope and polarized-light microscope. The results show that both of the thermal diffusivities and the thermal conductivities of C/C composites along the longitudinal direction of fibers gradually increase with HTT. The C/C composite prepared by using AR pitch as a matrix precursor possesses obvious graphite-like layer structure, exhibiting the highest thermal conductivity. The room-temperature thermal conductivity and th
Objective To explore the postmortem diffusion rule of Aconitum alkaloids and their metabolites in poisoned rabbits, and to provide a reference for identifying the antemortem poisoning or postmortem ...poisoning of Aconitum alkaloids. Methods Twenty-four rabbits were sacrificed by tracheal clamps. After 1 hour, the rabbits were administered with aconitine LD50 in decocting aconite root powder by intragastric administration. Then, they were placed supine and stored at 25 ℃. The biological samples from 3 randomly selected rabbits were collected including heart blood, peripheral blood, urine, heart, liver, spleen, lung and kidney tissues at 0 h, 4 h, 8 h, 12 h, 24 h, 48 h, 72 h and 96 h after intragastric administration, respectively. Aconitum alkaloids and their metabolites in the biological samples were analyzed by high performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS）. Results At 4 h after intragastric administration, Aconitum alkaloids and their metabolites could be detected in heart blood,
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