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1.
Nat Commun ; 14(1): 3769, 2023 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-37355682

RESUMO

Under magnetic fields, quantum magnets often undergo exotic phase transitions with various kinds of order. The discovery of a sequence of fractional magnetization plateaus in the Shastry-Sutherland compound SrCu2(BO3)2 has played a central role in the high-field research on quantum materials, but so far this system could only be probed up to half the saturation value of the magnetization. Here, we report the first experimental and theoretical investigation of this compound up to the saturation magnetic field of 140 T and beyond. Using ultrasound and magnetostriction techniques combined with extensive tensor-network calculations (iPEPS), several spin-supersolid phases are revealed between the 1/2 plateau and saturation (1/1 plateau). Quite remarkably, the sound velocity of the 1/2 plateau exhibits a drastic decrease of -50%, related to the tetragonal-to-orthorhombic instability of the checkerboard-type magnon crystal. The unveiled nature of this paradigmatic quantum system is a new milestone for exploring exotic quantum states of matter emerging in extreme conditions.


Assuntos
Campos Magnéticos , Imãs , Fenômenos Químicos , Fenômenos Físicos , Registros
2.
J Prev Alzheimers Dis ; 9(4): 752-757, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36281680

RESUMO

BACKGROUND: There is growing interest in examining objective markers for early identification and behavioral intervention to prevent dementia and mild cognitive impairment in clinical and community settings. OBJECTIVE: To investigate the association between salivary alpha-amylase as an objective measure of psychological stress response and mild cognitive impairment for the implication of psychological stress in the development of mild cognitive impairment. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study involved 865 participants aged ≥ 65 years. A saliva sample was collected in the morning, and the levels of salivary alpha-amylase were assayed. Mild cognitive impairment was evaluated using the Japanese version of the Montreal Cognitive Assessment; a score < 26 was indicative of mild cognitive impairment. A multivariable logistic regression model was used to examine the association of salivary alpha-amylase and mild cognitive impairment after adjusting for age, sex, current drinking status, current smoking status, body mass index, hypertension, diabetes mellitus, physical activity, education, social support, social network, and heart rate variability. RESULTS: Salivary alpha-amylase was associated with mild cognitive impairment (the multivariable-adjusted odds ratio [95% confidence interval] for the 1-standard deviation increment of log-transformed salivary alpha-amylase was 1.24 [1.07-1.44]). This significant association persisted after adjusting for various confounding factors. CONCLUSION: Elevation of salivary alpha-amylase was associated with mild cognitive impairment among Japanese community-dwelling older adults. This suggests that salivary alpha-amylase is a useful objective marker of psychological stress responses associated with mild cognitive impairment.


Assuntos
Disfunção Cognitiva , alfa-Amilases Salivares , Humanos , Idoso , Estudos Transversais , Japão , Testes de Estado Mental e Demência , Biomarcadores
3.
Phys Rev Lett ; 127(15): 156601, 2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34678000

RESUMO

Magnetoresistance of the correlated narrow-gap semiconductor FeSi was investigated by the radio frequency self-resonant spiral coil technique in magnetic fields up to 500 T, which is supplied by an electromagnetic flux compression megagauss generator. Semiconductor-to-metal transition accomplishes around 270 T observed as a sharp kink in the magnetoresistance, which implies the closing of the hybridization gap by the Zeeman shift of band edges. In the temperature-magnetic field phase diagram, the semiconductor-metal transition field is found to be almost independent of temperature, which is in contrast to a characteristic magnetic field associated with the hopping magnetoconduction in the in-gap localized states, exhibiting a notable temperature dependence.

4.
Rev Sci Instrum ; 92(3): 033902, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33819992

RESUMO

Single-turn coil (STC) technique is a convenient way to generate ultrahigh magnetic fields of more than 100 T. During the field generation, the STC explosively destructs outward due to the Maxwell stress and Joule heating. Unfortunately, the STC does not work at its full potential because it has already expanded when the maximum magnetic field is reached. Here, we propose an easy way to delay the expansion and increase the maximum field by using a mass-loaded STC. By loading clay on the STC, the field profile drastically changes, and the maximum field increases by 4%. This method offers access to higher magnetic fields for physical property measurements.

5.
Sci Rep ; 10(1): 19959, 2020 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-33203957

RESUMO

Salivary glands (SGs) are very important for maintaining the physiological functions of the mouth. When SGs regenerate and repair from various damages, including mechanical, radiological, and immune diseases, acinar and granular duct cells originate from intercalated duct cells. However, the recovery is often insufficient because of SGs' limited self-repair function. Furthermore, the precise repair mechanism has been unclear. Here, we focused on CD49f, one of the putative stem cell markers, and characterized CD49f positive cells (CD49f+ cells) isolated from male murine SGs. CD49f+ cells possess self-renewal ability and express epithelial and pluripotent markers. Compared to CD49f negative cells, freshly isolated CD49f+ cells highly expressed inhibin beta A and beta B, which are components of activin that has anti-proliferative effects. Notably, an inhibitor of activin, follistatin was expressed in mechanically-damaged SGs, meanwhile no follistatin was expressed in normal SGs in vivo. Moreover, sub-cultured CD49f+ cells highly expressed both Follistatin and a series of proliferative genes, expressions of which were decreased by Follistatin siRNA. These findings indicated that the molecular interaction between activin and follistatin may induce CD49f+ cells proliferation in the regeneration and repair of mouse SGs.


Assuntos
Proliferação de Células , Folistatina/metabolismo , Integrina alfa6/metabolismo , Regeneração , Glândulas Salivares/citologia , Células-Tronco/citologia , Animais , Células Cultivadas , Folistatina/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Glândulas Salivares/lesões , Glândulas Salivares/metabolismo , Células-Tronco/metabolismo
6.
Phys Rev Lett ; 124(10): 102501, 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32216444

RESUMO

Interaction cross sections for ^{42-51}Ca on a carbon target at 280 MeV/nucleon have been measured for the first time. The neutron number dependence of derived root-mean-square matter radii shows a significant increase beyond the neutron magic number N=28. Furthermore, this enhancement of matter radii is much larger than that of the previously measured charge radii, indicating a novel growth in neutron skin thickness. A simple examination based on the Fermi-type distribution, and mean field calculations point out that this anomalous enhancement of the nuclear size beyond N=28 results from an enlargement of the core by a sudden increase in the surface diffuseness of the neutron density distribution, which implies the swelling of the bare ^{48}Ca core in Ca isotopes beyond N=28.

7.
Phys Rev Lett ; 125(26): 267207, 2020 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-33449724

RESUMO

The entire magnetization process of TlCuCl_{3} has been experimentally investigated up to 100 T employing the single-turn technique. The upper critical field H_{c2} is observed to be 86.1 T at 2 K. A convex slope of the M-H curve between the lower and upper critical fields (H_{c1} and H_{c2}) is clearly observed, which indicates that a particle-hole symmetry is broken in TlCuCl_{3}. By quantum Monte Carlo simulation and the bond-operator theory method, we find that the particle-hole symmetry breaking results from strong interdimer interactions.

8.
Occup Med (Lond) ; 69(6): 406-411, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31263899

RESUMO

BACKGROUND: Commercial drivers suffering from excessive daytime sleepiness (EDS) have been identified as a major cause of road traffic accidents. Alcohol usage directly affects sleep, adversely affecting next-day alertness and performance. AIMS: To examine the relationship between alcohol consumption and EDS among commercial truck drivers in Japan and the implications of this on public health. METHODS: All participants in this cross-sectional study were commercial motor vehicle drivers from Tokyo and Niigata Prefecture. Participants completed a self-administered questionnaire with details of their age, body mass index, alcohol consumption, Epworth Sleepiness Scale (ESS) score and tobacco usage. Participants' oxygen desaturation index was determined by a pulse oximetry device that participants took home. RESULTS: A total of 1422 males registered with the Japan Trucking Association and aged 20-69 years participated. The multivariate-adjusted odds ratio (OR) of EDS among participants aged <43 years was 0.81 (95% confidence interval (CI) 0.47-1.40) for light drinkers, 0.93 (95% CI 0.51-1.70) for moderate drinkers and 0.61 (95% CI 0.21-1.79) for heavy drinkers, compared to non-drinkers. The multivariate-adjusted OR among participants aged ≥43 years was 1.42 (95% CI 0.59-3.45) for light drinkers, 1.53 (95% CI 0.63-3.75) for moderate drinkers and 3.37 (95% CI 1.14-9.96) for heavy drinkers (P for interaction = 0.05). CONCLUSION: We found that the association between ESS and alcohol intake was more evident among those aged ≥43 years, who reported higher levels of EDS with increased alcohol consumption.


Assuntos
Consumo de Bebidas Alcoólicas/efeitos adversos , Sonolência , Acidentes de Trânsito/prevenção & controle , Adulto , Idoso , Condução de Veículo , Estudos Transversais , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Veículos Automotores , Razão de Chances , Oxigênio/sangue , Adulto Jovem
9.
Rev Sci Instrum ; 89(9): 095106, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30278742

RESUMO

A peak field of 1200 T was generated by the electromagnetic flux-compression (EMFC) technique with a newly developed megagauss generator system. Magnetic fields closely up to the turn-around peak were recorded by a reflection-type Faraday rotation magnetic-field optical-fiber probe. The performance was analyzed and compared with data obtained by the preceding EMFC experiments to show a significant increase in the liner imploding speed of up to 5 km/s.

10.
J Dent Res ; 97(7): 820-827, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29481294

RESUMO

Ameloblasts responsible for enamel formation express matrix metalloproteinase 20 (MMP20), an enzyme that cleaves enamel matrix proteins, including amelogenin (AMELX) and ameloblastin (AMBN). Previously, we showed that continuously erupting incisors from transgenic mice overexpressing active MMP20 had a massive cell infiltrate present within their enamel space, leading to enamel mineralization defects. However, effects of MMP20 overexpression on mouse molars were not analyzed, although these teeth more accurately represent human odontogenesis. Therefore, MMP20-overexpressing mice ( Mmp20+/+Tg+) were assessed by multiscale analyses, combining several approaches from high-resolution micro-computed tomography to enamel organ immunoblots. During the secretory stage at postnatal day 6 (P6), Mmp20+/+Tg+ mice had a discontinuous ameloblast layer and, unlike incisors, molar P12 maturation stage ameloblasts abnormally migrated away from the enamel layer into the stratum intermedium/stellate reticulum. TOPflash assays performed in vitro demonstrated that MMP20 expression promoted ß-catenin nuclear localization and that MMP20 expression promoted invasion through Matrigel-coated filters. However, for both assays, significant differences were eliminated in the presence of the ß-catenin inhibitor ICG-001. This suggests that MMP20 activity promotes cell migration via the Wnt pathway. In vivo, the unique molar migration of amelogenin-expressing ameloblasts was associated with abnormal deposition of ectopic calcified nodules surrounding the adherent enamel layer. Enamel content was assessed just prior to eruption at P15. Compared to wild-type, Mmp20+/+Tg+ molars exhibited significant reductions in enamel thickness (70%), volume (60%), and mineral density (40%), and MMP20 overexpression resulted in premature cleavage of AMBN, which likely contributed to the severe defects in enamel mineralization. In addition, Mmp20+/+Tg+ mouse molar enamel organs had increased levels of inactive p-cofilin, a protein that regulates cell polarity. These data demonstrate that increased MMP20 activity in molars causes premature degradation of ameloblastin and inactivation of cofilin, which may contribute to pathological Wnt-mediated cell migration away from the enamel layer.


Assuntos
Ameloblastos/enzimologia , Amelogênese/fisiologia , Metaloproteinase 20 da Matriz/metabolismo , Dente Molar/enzimologia , Fatores de Despolimerização de Actina/metabolismo , Amelogenina/metabolismo , Animais , Animais Recém-Nascidos , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Movimento Celular , Proteínas do Esmalte Dentário/metabolismo , Immunoblotting , Camundongos , Camundongos Transgênicos , Pirimidinonas/farmacologia , Via de Sinalização Wnt , Microtomografia por Raio-X
11.
Psychol Med ; 47(11): 1936-1946, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28374662

RESUMO

BACKGROUND: The Fukushima Nuclear Energy Workers' Support (NEWS) Project Study previously showed that experiences related to the Fukushima nuclear disaster on 11 March 2011 had a great impact on psychological states, including post-traumatic stress response (PTSR) and general psychological distress (GPD), among the Fukushima nuclear plant workers. To determine the causal relationship between disaster-related experiences and levels of psychological states, we conducted a 3-year longitudinal study from 2011 to 2014. METHOD: PTSR and GPD of the nuclear plant workers were assessed by annual questionnaires conducted from 2011 to 2014. The present study included a total of 1417 workers who provided an assessment at baseline (2011). A total of 4160 observations were used in the present analysis. The relationship between disaster-related experiences and psychological states over time was analysed using mixed-effects logistic regression models. RESULTS: A declining influence of disaster-related experiences on PTSR over time was found. However, the impact on PTSR remained significantly elevated even 3 years after the disaster in several categories of exposure including the experience of life-threatening danger, experiences of discrimination, the witnessing of plant explosion, the death of a colleague and home evacuation. The associations between GPD and disaster-related experiences showed similar effects. CONCLUSIONS: The effects of disaster-related experiences on psychological states among the nuclear plant workers reduced over time, but remained significantly high even 3 years after the event.


Assuntos
Desastres , Acidente Nuclear de Fukushima , Doenças Profissionais/fisiopatologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Estresse Psicológico/fisiopatologia , Adulto , Desastres/estatística & dados numéricos , Feminino , Humanos , Japão , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Doenças Profissionais/etiologia , Transtornos de Estresse Pós-Traumáticos/etiologia , Estresse Psicológico/etiologia
12.
Br J Surg ; 103(12): 1608-1615, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27550722

RESUMO

BACKGROUND: The use of oral prophylactic antibiotics for the prevention of surgical-site infection (SSI) in patients undergoing laparoscopic surgery for colorectal cancer is controversial. The aim of this RCT was to evaluate whether intravenous perioperative antibiotics are inferior to combined preoperative oral and perioperative intravenous antibiotics in this setting. METHODS: Patients undergoing elective laparoscopic colorectal resection in a single cancer centre were assigned randomly to combined preoperative oral antibiotics (metronidazole and kanamycin) and perioperative intravenous antibiotics (cefmetazole) (oral/IV group) or to perioperative intravenous antibiotics (cefmetazole) alone (IV-only group). Patients were stratified for the analyses based on type of operation (colonic surgery, anterior resection or abdominoperineal resection), preoperative use of mechanical bowel preparation, preoperative chemoradiotherapy and the presence of diabetes mellitus. The primary endpoint was the overall rate of SSI. Secondary endpoints were the rates of incisional site infection, organ/space infection, anastomotic leakage, intra-abdominal abscess, adverse events and postoperative complications. RESULTS: Of 540 patients offered participation in the trial in 2013-2014, 515 agreed to take part and were randomized. Some 256 patients in the IV-only group and 255 in the oral/IV group completed the treatment per protocol. The overall rate of SSI was 7·8 per cent (20 of 256) in the IV-only group and 7·8 per cent (20 of 255) in the oral/IV group, confirming that perioperative administration of intravenous antibiotics alone was not inferior to the combined regimen (P = 0·017). There were no differences in rates of incisional site infection (5·5 versus 5·9 per cent respectively), organ/space infection (2·3 versus 2·0 per cent) or other secondary endpoints between the two groups. CONCLUSION: Intravenous perioperative antimicrobial prophylaxis alone is not inferior to combined preoperative oral and intravenous perioperative prophylaxis with regard to SSI in patients with colorectal cancer undergoing elective laparoscopic resection. Registration number: UMIN000019339 ( http://www.umin.ac.jp/ctr/).


Assuntos
Antibacterianos/administração & dosagem , Antibioticoprofilaxia/métodos , Neoplasias Colorretais/cirurgia , Laparoscopia/métodos , Infecção da Ferida Cirúrgica/prevenção & controle , Administração Oral , Adulto , Idoso , Idoso de 80 Anos ou mais , Fístula Anastomótica/etiologia , Cefmetazol/administração & dosagem , Colectomia/métodos , Quimioterapia Combinada , Feminino , Humanos , Infusões Intravenosas , Cuidados Intraoperatórios/métodos , Canamicina/administração & dosagem , Laparoscopia/efeitos adversos , Masculino , Metronidazol/administração & dosagem , Pessoa de Meia-Idade , Complicações Pós-Operatórias/etiologia , Cuidados Pré-Operatórios/métodos
13.
Phys Rev Lett ; 116(17): 179801, 2016 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-27176544
14.
Cortex ; 79: 1-13, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27085891

RESUMO

Electrocorticograms (ECoG) provide a unique opportunity to monitor neural activity directly at the cortical surface. Ten patients with subdural electrodes covering ventral and lateral anterior temporal regions (ATL) performed a picture naming task. Temporal representational similarity analysis (RSA) was used, for the first time, to compare spatio-temporal neural patterns from the ATL surface with pre-defined theoretical models. The results indicate that the neural activity in the ventral subregion of the ATL codes semantic representations from 250 msec after picture onset. The observed activation similarity was not related to the visual similarity of the pictures or the phonological similarity of their names. In keeping with convergent evidence for the importance of the ATL in semantic processing, these results provide the first direct evidence of semantic coding from the surface of the ventral ATL and its time-course.


Assuntos
Eletrocorticografia , Reconhecimento Visual de Modelos/fisiologia , Lobo Temporal/fisiologia , Adolescente , Adulto , Mapeamento Encefálico/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estimulação Luminosa , Tempo de Reação/fisiologia , Adulto Jovem
15.
Org Biomol Chem ; 14(6): 2127-33, 2016 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-26782816

RESUMO

The addition of InBr3 to the oxidative Sonogashira cross-coupling reaction of 2-ethynylaniline with (E)-trimethyl(3,3,3-trifluoroprop-1-enyl)silane led to a dramatic increase in the reactivity to afford the corresponding 1,3-enynes bearing a trifluoromethyl group on their terminal sp(2) carbon. The subsequent cyclization of these 1,3-enynes under palladium catalysis provides access to the corresponding indoles bearing a 3,3,3-trifluoroprop-1-enyl group at their 2-position.

16.
Annu Int Conf IEEE Eng Med Biol Soc ; 2016: 1393-1396, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28268586

RESUMO

In brain function measurements by near-infrared spectroscopy (NIRS), we focus on the temporal changes in the oxygenated and deoxygenated hemoglobin concentrations and propose an analytical approach to the temporal changes of the hemoglobin concentrations' cross-correlation coefficient in the brain functional signals. The cross-correlation coefficient between the oxygenated and deoxygenated hemoglobin concentrations shows negative values for brain activity and positive values for hemodynamic changes. Experiments with a 16-channel functional NIRS system show that our proposed approach clarifies the interpretation of the measured NIRS signals and it can be used to estimate the influence of hemodynamic change on brain activity.


Assuntos
Mapeamento Encefálico , Encéfalo/diagnóstico por imagem , Espectroscopia de Luz Próxima ao Infravermelho , Encéfalo/metabolismo , Feminino , Lobo Frontal/diagnóstico por imagem , Hemodinâmica , Hemoglobinas/metabolismo , Humanos , Masculino , Fenômenos Fisiológicos do Sistema Nervoso , Oxigênio/química , Fatores de Tempo , Adulto Jovem
17.
Phys Rev Lett ; 115(26): 267207, 2015 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-26765023

RESUMO

We experimentally demonstrate one-way transparency of light in multiferroic CuB(2)O(4). The material is rendered transparent for light propagating in one direction, while opaque for light propagating in the opposite direction. The novel transparency results from a destructive interference of the electric dipole and magnetic dipole transitions. The realization of the effect has been accomplished by the application of a high magnetic field and the proper selection of the propagation direction of light in agreement with our quantum mechanical formulation of nonreciprocal directional dichroism.

18.
Diabetologia ; 56(7): 1494-502, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23568273

RESUMO

AIMS/HYPOTHESIS: The aim of this work was to investigate whether measurement of the mean common carotid intima-media thickness (CIMT) improves cardiovascular risk prediction in individuals with diabetes. METHODS: We performed a subanalysis among 4,220 individuals with diabetes in a large ongoing individual participant data meta-analysis involving 56,194 subjects from 17 population-based cohorts worldwide. We first refitted the risk factors of the Framingham heart risk score on the individuals without previous cardiovascular disease (baseline model) and then expanded this model with the mean common CIMT (CIMT model). The absolute 10 year risk for developing a myocardial infarction or stroke was estimated from both models. In individuals with diabetes we compared discrimination and calibration of the two models. Reclassification of individuals with diabetes was based on allocation to another cardiovascular risk category when mean common CIMT was added. RESULTS: During a median follow-up of 8.7 years, 684 first-time cardiovascular events occurred among the population with diabetes. The C statistic was 0.67 for the Framingham model and 0.68 for the CIMT model. The absolute 10 year risk for developing a myocardial infarction or stroke was 16% in both models. There was no net reclassification improvement with the addition of mean common CIMT (1.7%; 95% CI -1.8, 3.8). There were no differences in the results between men and women. CONCLUSIONS/INTERPRETATION: There is no improvement in risk prediction in individuals with diabetes when measurement of the mean common CIMT is added to the Framingham risk score. Therefore, this measurement is not recommended for improving individual cardiovascular risk stratification in individuals with diabetes.


Assuntos
Doenças Cardiovasculares/epidemiologia , Espessura Intima-Media Carotídea , Diabetes Mellitus/epidemiologia , Humanos , Infarto do Miocárdio/epidemiologia , Fatores de Risco , Acidente Vascular Cerebral/epidemiologia
19.
J Chem Phys ; 138(2): 024302, 2013 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-23320678

RESUMO

Cascade Si LVV Auger decays following KL(23)L(23) Auger transitions have been measured in SiF(4) molecule using an electron spectrometer combined with monochromatized undulator radiation. Molecular cascade processes from the two 2p holes states largely generate wide band structures in the spectra due to sequential electron emission leading to multiple valence holes. However, a peak with high yield is observed for the first time at about 103 eV, an energy being considerably higher than the energies of the normal LVV Auger electron, in the instance of the resonant excitation of Si 1s electron into the vacant molecular orbital. This peak is presumed to originate from the participator decay from the state with two 2p holes and one excited electron into the state with one 2p hole and one valence hole. A similar peak with less intensity is detected in the photoexcitation of the 1s electron into a Rydberg orbital. After the normal KL(23)L(23) Auger transition, the resultant cascade spectrum shows several peaks, e.g., 61 eV, 76 eV, and 82 eV. The former two peaks are assigned to the Auger transitions of Si atoms produced through molecular ion dissociation after cascade decays, and the latter is probably ascribed to the second step Auger decay into states having a 2p hole together with two valence holes.

20.
Epidemiol Infect ; 140(11): 2074-81, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22281015

RESUMO

This study determined the prevalence and antimicrobial susceptibility of Salmonella isolated from broiler flocks in Japan. Caecal dropping samples were collected from 288 broiler flocks between November 2007 and February 2010. Salmonella was prevalent in 248 (86·1%) broiler flocks. The top three serovars were S. Infantis, S. Manhattan and S. Schwarzengrund. S. Infantis was found in all regions tested in this study. However, S. Manhattan and S. Schwarzengrund were frequently found only in the western part of Japan. High antimicrobial resistance rates were observed against oxytetracycline (90·2%), dihydrostreptomycin (86·7%) and ampicillin (36·5%), and 258 (90·5%) of 285 isolates were resistant to two or more antimicrobial agents. Interestingly, 26·3% of isolates were resistant to ceftiofur, especially 38·1% of S. Infantis isolates, although its use in broilers has not been approved in Japan. This study showed that Salmonella is highly prevalent (86·1%) in Japanese broiler flocks, that 90·5% of Salmonella isolates were multidrug-resistant, and that S. Infantis frequently exhibited resistance to cephalosporin antimicrobial agents.


Assuntos
Galinhas , Farmacorresistência Bacteriana , Doenças das Aves Domésticas/epidemiologia , Salmonelose Animal/epidemiologia , Salmonella enterica/efeitos dos fármacos , Ampicilina/farmacologia , Animais , Antibacterianos/farmacologia , Cefalosporinas/farmacologia , Sulfato de Di-Hidroestreptomicina/farmacologia , Farmacorresistência Bacteriana Múltipla , Fezes/microbiologia , Japão/epidemiologia , Testes de Sensibilidade Microbiana , Oxitetraciclina/farmacologia , Doenças das Aves Domésticas/microbiologia , Salmonelose Animal/microbiologia , Salmonella enterica/isolamento & purificação
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