Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 422
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-32173528

RESUMO

Targeting proteins that are overexpressed in cancer cells is the major strategy of molecular imaging and drug delivery systems. The 67-kDa laminin receptor (67LR), also known as oncofetal antigen, is overexpressed in several types of cancer, including melanoma, multiple myeloma, cervical cancer and bile duct carcinoma. 67LR is involved in tumour growth, tumour metastasis and drug resistance. Green tea polyphenol (-)-epigallocatechin-3-O-gallate (EGCG) directly binds to cell-surface 67LR and induces apoptosis through the protein kinase B (Akt)/endothelial nitric oxide synthase/nitric oxide/cyclic GMP (cGMP) axis. Here we report the optimum hydroxyl group for the utilization of EGCG as a novel fluorescent EGCG-mimic imaging probe based on 67LR agonist characters, including Akt activation and inhibitory effect on viable cell number in cancer cells. 67LR specific targeting is unambiguously confirmed with the use of a non-labelled EGCG competitive assay and 67LR knockdown. Importantly, this probe strongly binds to multiple myeloma cells compared with its binding to normal cells.

2.
Free Radic Res ; : 1-231, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32183600

RESUMO

Exposure to asbestos fiber is central to mesothelial carcinogenesis. Recent sequencing studies on human and rodent malignant mesothelioma (MM) revealed frequently mutated genes, including CDKN2A, BAP1 and NF2. Crocidolite directly or indirectly catalyzes the generation of hydroxyl radicals, which appears to be the major driving force for mesothelial mutations. DNA base modification is an oxidative DNA damage mechanism, where 8-hydroxy-2'-deoxyguanosine (8-OHdG) is the most abundant modification both physiologically and pathologically. Multiple distinct mechanisms work together to decrease the genomic level of 8-OHdG through the enzymatic activities of Mutyh, Ogg1 and Mth1. Knockout of one or multiple enzymes is not lethal but increases the incidence of tumors. Here, we used single knockout (KO) mice to test whether the deficiency of these three genes affects the incidence and prognosis of asbestos-induced MM. Intraperitoneal injection of 3 mg crocidolite induced MM at a fraction of 14.8% (4/27) in Mth1 KO, 41.4% (12/29) in Mutyh KO and 24.0% (6/25) in Ogg1 KO mice, whereas 31.7% (20/63) induction was observed in C57BL/6 wild-type (Wt) mice. The lifespan of female Mth1 KO mice was longer than that of female Wt mice (p = 0.0468). Whole genome scanning of MM with array-based comparative genomic hybridization revealed rare genomic alterations compared to MM in rats and humans. These results indicate that neither Mutyh deficiency nor Ogg1 deficiency promotes crocidolite-induced MM in mice, but the sanitizing nucleotide pool with Mth1 is advantageous in crocidolite-induced mesothelial carcinogenesis.

3.
Cancer Sci ; 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32012400

RESUMO

We previously revealed that tumor cell-derived angiopoietin-like protein 2 (ANGPTL2) accelerates the metastatic capacity of tumors in an autocrine/paracrine manner by activating tumor cell motility and invasiveness and the epithelial-mesenchymal transition. However, the effects of ANGPTL2 on cancer cell glycolytic metabolism, which is a hallmark of tumor cells, are unknown. Here we report evidence supporting a role for tumor cell-derived ANGPTL2 in establishing a preference for glycolytic metabolism. We report that a highly metastatic lung cancer cell subline expressing abundant ANGPTL2 showed upregulated expression of the glucose transporter GLUT3 as well as enhanced glycolytic metabolism relative to a less metastatic parental line. Most notably, ANGPTL2 overexpression in the less metastatic line activated glycolytic metabolism by increasing GLUT3 expression. Moreover, ANGPTL2 signaling through integrin α5ß1 increased GLUT3 expression by increasing transforming growth factor-ß (TGF-ß) signaling and expression of the downstream transcription factor zinc finger E-box binding homeobox 1 (ZEB1). Conversely, ANGPTL2 knockdown in the highly metastatic subline decreased TGF-ß1, ZEB1, and GLUT3 expression and antagonized glycolytic metabolism. In primary tumor cells from patients with lung cancer, ANGPTL2 expression levels correlated with GLUT3 expression. Overall, this work suggests that tumor cell-derived ANGPTL2 accelerates activities associated with glycolytic metabolism in lung cancer cells by activating TGF-ß-ZEB1-GLUT3 signaling.

4.
Cancer Sci ; 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32080953

RESUMO

The onset of malignant mesothelioma (MM) is linked to exposure to asbestos fibers. Asbestos fibers are classified as serpentine (chrysotile) or amphibole, which includes the crocidolite, amosite, anthophyllite, tremolite, and actinolite types. Although few studies have been undertaken, anthophyllite has been shown to be associated with mesothelioma, and tremolite, a contaminant in talc and chrysotile, is a risk factor for carcinogenicity. Here, after characterizing the length and width of these fibers by scanning electron microscopy, we explored the cytotoxicity induced by tremolite and anthophyllite in cells from an immortalized human mesothelial cell line (MeT5A), murine macrophages (RAW264.7), and in a rat model. Tremolite and short anthophyllite fibers were phagocytosed and localized to vacuoles, whereas the long anthophyllite fibers were caught on the pseudopod of the MeT5A and Raw 264.7 cells, according to transmission electron microscopy. The results from a 2-day time-lapse study revealed that tremolite was engulfed and damaged the MeT5A and RAW264.7 cells, but anthophyllite was not cytotoxic to these cells. Intraperitoneal injection of tremolite in rats induced diffuse serosal thickening, whereas anthophyllite formed focal fibrosis and granulomas on peritoneal serosal surfaces. Furthermore, the loss of Cdkn2a/2b, which are the most frequently lost foci in human MM, were observed in 8 cases of rat MM (homozygous deletion [5/8] and loss of heterozygosity [3/8]) by array-based comparative genomic hybridization techniques. These results indicate that tremolite initiates mesothelial injury and persistently frustrates phagocytes, causing subsequent peritoneal fibrosis and MM. The possible mechanisms of carcinogenicity based on fiber diameter/length are discussed.

5.
Jpn J Infect Dis ; 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32009056

RESUMO

This study investigated quinolone nonsusceptible Streptococcus canis with point mutations in quinolone resistance-determining regions (QRDRs). After selecting targets from 185 isolates, we conducted antimicrobial susceptibility testing using levofloxacin, ciprofloxacin, norfloxacin, and moxifloxacin. We also determined amino acid sequences of QRDRs in gyrA/ gyrB/parC/parE genes and their point mutations. Finally, we performed S. canis-derived M-like protein (SCM) allele typing, multilocus sequence typing, and antimicrobial resistance genotyping. Correlations between nonsusceptible strains and their related factors were examined. We found 13 (7.0%) nonsusceptible isolates consisting of two classes, high-level minimum inhibitory concentrations (MICs) (n = 7, 3.8%), and low-level MICs (n = 6, 3.2%). The mutations Ser81Phe/Ser81Tyr/Glu85Lys in gyrA, Ser67Phe/Ser67Tyr/Asp71Tyr in parC, Asp438Asn in parE, and Gly408Asp in gyrB were observed in these nonsusceptible strains. The common mutations were Ser81 and Ser67/Asp71, whereas we found one strain each with Glu85, Asp438 and Gly408 mutations. There was a significant correlation between the nonsusceptible isolates and presence of SCM allele type 2, sequence type 46, tetracycline-resistance genes, and macrolide/lincosamide-resistance genes. These results could be used in the future by veterinarians while treating companion animals with clinical symptoms of streptococcal infections.

6.
Jpn J Infect Dis ; 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32009057

RESUMO

This study assessed whether Streptococcus agalactiae isolates from companion animals are different from isolates of human origin. Beta-hemolytic S. agalactiae were collected from a veterinary laboratory center and a university hospital. Strains were identified using 16S rRNA amplicon sequencing and amplification of the species-specific dltS gene. We conducted virulence gene profiling, capsular genotyping, determination of clonal complex (CC), and antimicrobial resistance (AMR) phenotyping/genotyping. Twenty non-invasive isolates recovered from animals together with fifteen non-invasive isolates from adult humans were comparatively analyzed in this study. We found significant differences in virulence gene profile of bca-rib-lmb-cylE (40.0% vs. 93.3%) and possession of bac (30.0% vs. 0%) between animal-origin/human-origin non-invasive strains. We observed significant difference in the distribution of CC1 between the two non-invasive populations. There were significant differences in prevalence of tetracycline resistance genotypes (60.0% vs. 20.0%) and absence of AMR genotypes (30.0% vs. 80.0%), and AMR rates of tetracycline (35.0% vs. 0%) and fluoroquinolone (20.0% vs. 66.7%) between the two non-invasive populations. These observations suggest different features, in terms of virulence gene profile, CC, and AMR genotype/phenotype, of non-invasive isolates of animal-origin compared to those of human-origin.

7.
Chem Phys Lipids ; 227: 104871, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31923389

RESUMO

Recent studies by our group have suggested that the vitamin D3 decomposition product VDP1 [(1R,3aR,7aR)-1-[(1R)-1,5-dimethylhexyl]octahydro-7a-methyl-4H-inden-4-one] confers the potent bactericidal action to Helicobacter pylori by targeting the membranal dimyristoyl-phosphatidylethanolamine (di-14:0 PE). In this study we synthesized a new VDP1 derivative to advance further investigation as for the correlative relationship between VDP1 structure and anti-H. pylori activity or PE vesicle collapse induction activity. The derivative VD3-7 [(1R,7aR)-4-fluoro-7a-methyl-1-((R)-6-methylheptan-2-yl)octahydro-1H-indene] retained a fluorine atom in place of the oxygen atom of VDP1. The fluorination of the carbonyl portion of VDP1 forfeited the effective anti-H. pylori activity. We, therefore, prepared Coomassie brilliant blue (CBB)-containing unilamellar vesicles consisting of various PE molecular species, and examined the vesicle collapse induction activity of either VDP1 or VD3-7 by detecting the CBB eluted from the PE unilamellar vesicles. VDP1 strongly induced CBB elution from the unilamellar vesicles of rectus-PE retaining the same two fatty acid side-chains shorter than carbon numbers 14, indicating that VDP1 specifically disrupted the vesicular conformation of those PE unilamellar vesicles. Meanwhile, VD3-7 had no influence on the structural stability of any PE unilamellar vesicles. This study obtained additional evidence that VDP1 acts as a bactericidal agent on H. pylori by targeting the membranal di-14:0 PE.

9.
Proc Natl Acad Sci U S A ; 116(49): 24470-24474, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31744873

RESUMO

The discovery of high-temperature (T c) superconductivity in monolayer FeSe on SrTiO3 raised a fundamental question: Whether high T c is commonly realized in monolayer iron-based superconductors. Tetragonal FeS is a key material to resolve this issue because bulk FeS is a superconductor with T c comparable to that of isostructural FeSe. However, difficulty in synthesizing tetragonal monolayer FeS due to its metastable nature has hindered further investigations. Here we report elucidation of band structure of monolayer FeS on SrTiO3, enabled by a unique combination of in situ topotactic reaction and molecular-beam epitaxy. Our angle-resolved photoemission spectroscopy on FeS and FeSe revealed marked similarities in the electronic structure, such as heavy electron doping and interfacial electron-phonon coupling, both of which have been regarded as possible sources of high T c in FeSe. However, surprisingly, high-T c superconductivity is absent in monolayer FeS. This is linked to the weak superconducting pairing in electron-doped multilayer FeS in which the interfacial effects are absent. Our results strongly suggest that the cross-interface electron-phonon coupling enhances T c only when it cooperates with the pairing interaction inherent to the superconducting layer. This finding provides a key insight to explore heterointerface high-T c superconductors.

10.
Microbiol Resour Announc ; 8(39)2019 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-31558629

RESUMO

Streptococcus canis is a ß-hemolytic bacterium that can cause invasive infections in animals and humans. Here, we report a draft genome sequence of S. canis strain OT1, isolated from a female dog owner with bacteremia without a dog bite. The draft genome comprises 2,030,366 bp in 48 contigs.

12.
EMBO J ; 38(17): e98441, 2019 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-31361039

RESUMO

Long non-coding RNAs (lncRNAs) function in a wide range of processes by diverse mechanisms, though their roles in regulation of oncogenes and/or tumor suppressors remain rather elusive. We performed a global search for lncRNAs affecting MYC activity using a systems biology-based approach with a K supercomputer and the GIMLET algorism based on local distance correlations. Consequently, MYMLR was identified and experimentally shown to maintain MYC transcriptional activity and cell cycle progression despite the low levels of expression. A proteomic search for MYMLR-binding proteins identified PCBP2, while it was also found that MYMLR places a 557-kb upstream enhancer region in the proximity of the MYC promoter in cooperation with PCBP2. These findings implicate a crucial role for MYMLR in regulation of the archetypical oncogene MYC and warrant future studies regarding the involvement of low copy number lncRNAs in regulation of other crucial oncogenes and tumor suppressor genes.


Assuntos
Neoplasias Pulmonares/genética , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , RNA Longo não Codificante/genética , Proteínas de Ligação a RNA/genética , Células A549 , Animais , Ciclo Celular , Linhagem Celular Tumoral , Proliferação de Células , Regulação para Baixo , Elementos Facilitadores Genéticos , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/metabolismo , Camundongos , Transplante de Neoplasias , Proteômica , Proteínas de Ligação a RNA/metabolismo , Biologia de Sistemas
13.
J Infect Chemother ; 25(12): 1037-1039, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31151810

RESUMO

Streptococcal toxic shock syndrome (STSS) is a systemic, life-threatening illness usually caused by invasive respiratory tract or skin and soft tissue infections of Streptococcus pyogenes (group A streptococcus, GAS). We report the case of an adult woman with lactational amenorrhea and GAS vulvovaginitis progressing to STSS. She was admitted to our hospital because of fever, lethargy, and a 2-week history of vaginal discharge; she also had hypotension and multiple organ failure. Blood and urine cultures yielded gram-positive cocci and GAS. After 14 days of antimicrobial therapy, she fully recovered without any complications. The vulvovaginitis was most likely the portal of entry for GAS, which is rarely recognized as a causative pathogen of vulvovaginitis. Lactational amenorrhea is thought to be a risk factor for GAS vulvovaginitis. It is important for clinicians to recognize the possibility of GAS vulvovaginitis in breastfeeding women with vaginal symptoms and consider the necessity of prompt antibiotic treatment.

14.
Nano Lett ; 19(6): 3737-3742, 2019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31038974

RESUMO

We have performed scanning angle-resolved photoemission spectroscopy with a nanometer-sized beam spot (nano-ARPES) on the cleaved surface of Pb5Bi24Se41, which is a member of the (PbSe)5(Bi2Se3)3 m homologous series (PSBS) with m = 4 consisting of alternate stacking of the topologically trivial insulator PbSe bilayer and four quintuple layers (QLs) of the topological insulator Bi2Se3. This allows us to visualize a mosaic of topological Dirac states at a nanometer scale coming from the variable thickness of the Bi2Se3 nanoislands (1-3 QLs) that remain on top of the PbSe layer after cleaving the PSBS crystal, because the local band structure of topological origin changes drastically with the thickness of the Bi2Se3 nanoislands. A comparison of the local band structure with that in ultrathin Bi2Se3 films on Si(111) gives us further insights into the nature of the observed topological states. This result demonstrates that nano-ARPES is a very useful tool for characterizing topological heterostructures.

15.
Ann Lab Med ; 39(5): 488-492, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31037868

RESUMO

No study has described Streptococcus dysgalactiae subsp. equisimilis (SDSE) isolates that cause repetitive infections (recurrence and reinfection). We compared the microbiological characteristics of SDSE causing repetitive infections with those causing single infections. Three patients with invasive infections were identified based on their medical records, and multiple SDSE isolates were collected at intervals over three weeks, using a laboratory repository. Isolates from 12 patients with single-episode infections served as controls. Six isolates were collected from three patients with first and second episodes of infection. All isolates causing either repetitive or single-episode infection were subjected to emm typing, multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), and random amplified polymorphic DNA (RAPD) analyses. Amplification of five virulence genes (sicG, prtF1, prtF2, lmb, and cbp), biofilm formation (BF), and cell invasion abilities (CIAs) were measured as virulent phenotypes. We observed close genetic similarities in the data obtained by emm typing, MLST, PFGE, and RAPD in four isolates from two patients, suggesting recurrence, whereas two isolates from one patient indicated genetic differences in these data, suggesting re-infection. The presence of the five virulence genes and the BF and CIA measurements appeared not to contribute to repetitive infections, compared with isolates causing single-episode infection. In conclusion, clinicians encountering patients with repetitive infections should be aware of both possibilities: recurrence with closely related strains and reinfection with different strains.


Assuntos
Infecções Estreptocócicas/diagnóstico , Streptococcus/genética , Eletroforese em Gel de Campo Pulsado , Genótipo , Humanos , Tipagem de Sequências Multilocus/métodos , RNA Ribossômico 16S/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico/métodos , Recidiva , Infecções Estreptocócicas/microbiologia , Infecções Estreptocócicas/patologia , Streptococcus/isolamento & purificação , Streptococcus/patogenicidade , Virulência/genética
16.
Oncogene ; 38(26): 5142-5157, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30894682

RESUMO

The receptor tyrosine kinase-like orphan receptor 1 (ROR1) is a transcriptional target of the lineage-survival oncogene NKX2-1/TTF-1 in lung adenocarcinomas. In addition to its kinase-dependent role, ROR1 functions as a scaffold protein to facilitate interaction between caveolin-1 (CAV1) and CAVIN1, and consequently maintains caveolae formation, which in turn sustains pro-survival signaling toward AKT from multiple receptor tyrosine kinases (RTKs), including epidermal growth factor receptor (EGFR), MET (proto-oncogene, receptor tyrosine kinase), and IGF-IR (insulin-like growth factor receptor 1). Therefore, ROR1 is an attractive target for overcoming EGFR-TKI resistance due to various mechanisms such as EGFR T790M double mutation and bypass signaling from other RTKs. Here, we report that ROR1 possesses a novel scaffold function indispensable for efficient caveolae-dependent endocytosis. CAVIN3 was found to bind with ROR1 at a site distinct from sites for CAV1 and CAVIN1, a novel function required for proper CAVIN3 subcellular localization and caveolae-dependent endocytosis, but not caveolae formation itself. Furthermore, evidence of a mechanistic link between ROR1-CAVIN3 interaction and consequential caveolae trafficking, which was found to utilize a binding site distinct from those for ROR1 interactions with CAV1 and CAVIN1, with RTK-mediated pro-survival signaling towards AKT in early endosomes in lung adenocarcinoma cells was also obtained. The present findings warrant future study to enable development of novel therapeutic strategies for inhibiting the multifaceted scaffold functions of ROR1 in order to reduce the intolerable death toll from this devastating cancer.


Assuntos
Adenocarcinoma de Pulmão/patologia , Cavéolas/fisiologia , Endocitose , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Neoplasias Pulmonares/patologia , Receptores Órfãos Semelhantes a Receptor Tirosina Quinase/metabolismo , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/metabolismo , Animais , Células COS , Cavéolas/metabolismo , Sobrevivência Celular/genética , Células Cultivadas , Endocitose/genética , Células HEK293 , Células HeLa , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Ligação Proteica/fisiologia , Células Sf9 , Transdução de Sinais/genética , Spodoptera
17.
Jpn J Infect Dis ; 72(4): 261-265, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-30814462

RESUMO

We determined the whole-genome sequence (WGS) of Streptococcus canis strain TA4 harboring the M-like protein gene (scm); the strain was isolated from a human patient presenting with bacteremia. The potential of type II-A clustered regularly interspaced short palindromic repeats (CRISPR) array-based typing was evaluated, and the genetic relation was elucidated between spacer genogroups and scm prevalence and/or polymorphisms among the isolates from 19 diseased companion animals and the human patient. CRISPRFinder and CRISPRCasFinder detected the type II-A locus with the same repeat sequences in strain TA4 and another WGS of S. canis strain, isolated from a cow with mastitis. An optimized PCR-based amplification method was used to sequence the region covering the locus around the leader and terminal repeat sequences. Among the 20 isolates sequenced, 16 strains (including TA4) were identified with the CRISPR array. We conducted comparative analysis of the homologous spacer sequences and performed grouping based on the successive common ancestral spacer types. These 16 isolates were assigned to five genogroups (A to E) with scm being absent in genogroup A. We found a relationship between genogroups C and E and allele type 1 of the deduced M-like protein. These preliminary findings suggest the feasibility of CRISPR array-based typing and a genetic relation between the spacer genogroups and scm prevalence and/or polymorphisms in the isolates.


Assuntos
Sistemas CRISPR-Cas , Tipagem Molecular , Infecções Estreptocócicas/microbiologia , Streptococcus/genética , Alelos , Animais , Bacteriemia/microbiologia , Proteínas de Bactérias/genética , Bovinos , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas/genética , DNA Bacteriano/genética , Feminino , Genoma Bacteriano/genética , Genótipo , Humanos , Japão/epidemiologia , Animais de Estimação/microbiologia , Filogenia , Análise de Sequência de DNA , Infecções Estreptocócicas/epidemiologia , Streptococcus/classificação , Streptococcus/isolamento & purificação
18.
Skeletal Radiol ; 48(11): 1759-1763, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30903257

RESUMO

OBJECTIVE: Full-spine radiographs are frequently ordered by spinal deformity surgeons to assess spinal imbalance. The radiologist interpretation of these films varies amongst providers. Detailed numeric measurements of the deformity are time-consuming. In this study, we hoped to better define current practice patterns for interpretation of spinal deformity films amongst musculoskeletal radiologists in North America. MATERIALS AND METHODS: An anonymous online survey was conducted amongst Society of Skeletal Radiology members. RESULTS: Only 26.5% of respondents (n = 57) routinely report pelvic tilt, 23.2% (n = 52) for sagittal vertical axis and 5.1% (n = 11) for Pelvic Incidence Lumbar Lordosis mismatch in adult spinal deformity. Furthermore, the majority of musculoskeletal radiologists (84.96%) dictate the same type of report for both adult and pediatric cases. CONCLUSIONS: The majority (n = 199, 70%) of 283 respondents state that no institutional standard template for full-spine dictations exists. The development of such templates listing appropriate parameters to include in the dictation may be useful in order to ensure that the radiologist's effort and clinical utility for the ordering provider are optimized.

19.
J Infect Chemother ; 25(7): 531-536, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30905629

RESUMO

The 2016 National Action Plan aims for reduction in antimicrobial resistance (AMR) to tetracyclines, third-generation cephalosporins, and fluoroquinolones in Escherichia coli isolates from livestock: to lower the tetracycline resistance of E. coli to 33% or less; to maintain the third-generation cephalosporin resistance of E. coli at the same level as in the other G7 countries as of 2020; and to maintain the fluoroquinolone resistance of E. coli at the same level as in the other G7 countries as of 2020. A relatively unexplored facet of reducing AMR is the impact of minimizing transmission of AMR strains by companion animals. In this study we compared AMR rates in Staphylococcus intermedius group (SIG) and E. coli isolated from diseased companion animals in an animal hospital before and after restriction of antimicrobial use. Our study spanned a 4.5-year period from 2014 to June 2018 during which antimicrobial use was restricted in 2016. During this period, abundance of methicillin-resistant SIG isolates from the hospital dropped from 41.5% to 9.3%, and that of extended-spectrum ß-lactamase (ESBL)-producing E. coli isolates dropped from 29.5% to 9.5%. Tests for antimicrobial susceptibility revealed significantly reduced rates of AMR to enrofloxacin and levofloxacin in SIG isolates, and to cefazolin in E. coli isolates after antimicrobial use was restricted. Our observations suggest that restriction of antimicrobial use, especially that of third-generation cephalosporins and fluoroquinolones, is an effective method for reducing AMR rates. These findings will be relevant in guiding antimicrobial restriction approaches in other animal hospitals and clinics.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Escherichia coli/fisiologia , Animais de Estimação/microbiologia , Staphylococcus intermedius/fisiologia , Animais , Antibacterianos/normas , Antibacterianos/uso terapêutico , Gatos , Cães , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/tratamento farmacológico , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/veterinária , Hospitais Veterinários/normas , Hospitais Veterinários/estatística & dados numéricos , Japão , Guias de Prática Clínica como Assunto , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus intermedius/isolamento & purificação
20.
Phys Rev Lett ; 122(7): 076402, 2019 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-30848650

RESUMO

Topological semimetals materialize a new state of quantum matter where massless fermions protected by a specific crystal symmetry host exotic quantum phenomena. Distinct from well-known Dirac and Weyl fermions, structurally chiral topological semimetals are predicted to host new types of massless fermions characterized by a large topological charge, whereas such exotic fermions are yet to be experimentally established. Here, by using angle-resolved photoemission spectroscopy, we experimentally demonstrate that a transition-metal silicide CoSi hosts two types of chiral topological fermions, a spin-1 chiral fermion and a double Weyl fermion, in the center and corner of the bulk Brillouin zone, respectively. Intriguingly, we found that the bulk Fermi surfaces are purely composed of the energy bands related to these fermions. We also find the surface states connecting the Fermi surfaces associated with these fermions, suggesting the existence of the predicted Fermi-arc surface states. Our result provides the first experimental evidence for the chiral topological fermions beyond Dirac and Weyl fermions in condensed-matter systems, and paves the pathway toward realizing exotic electronic properties associated with unconventional chiral fermions.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA