36 research outputs found
Antimicrobial susceptibility patterns of Brazilian Haemophilus parasuis field isolates
12 p.Haemophilus parasuis is the etiological agent of GlĂ€sserâs disease (GD), an ubiquitous infection of swine
characterized by systemic fibrinous polyserositis, polyarthritis and meningitis. Intensive use of antimicrobial
agents in swine husbandries during the last years triggered the development of antibiotic resistances in bacterial
pathogens. Thus, regular susceptibility testing is crucial to ensure efficacy of different antimicrobial agents to
this porcine pathogen. In this study, 50 clinical isolates from South Brazilian pig herds were characterized and
analyzed for their susceptibility to commonly used antibiotic. The identification and typing of clinical isolates
was carried out by a modified indirect hemagglutination assay combined with a multiplex PCR. The susceptibility
of each isolate was analyzed by broth microdilution method against a panel of antimicrobial compounds. We
found that field isolates are highly resistance to gentamycin, bacitracin, lincomycin and tiamulin, but sensitive to
ampicillin, clindamycin, neomycin, penicillin, danofloxacin and enrofloxacin. Furthermore, an individual
susceptibility analysis indicated that enrofloxacin is effective to treat clinical isolates with the exception of those
classified as serovarS
Altered indirect hemagglutination method for easy serotyping of Haemophilus parasuis
P. 15-21GlĂ€sserâs disease is an emergent bacterial disease that affects swine husbandries worldwide causing
important economic losses. The aetiological agent, Haemophilus parasuis, is currently divided in fifteen
serovars but an increasing number of non-typeable serovars have been reported. Indirect
hemagglutination (IHA) is indicated as a serotyping method for H. parasuis. In the present study, we
describe an additional step that aims to work around a possible obstacle in the original protocol that may
compromise the outcome of this assay. We observed that the choice of anticoagulant for blood collection
influences and/or impairs spontaneous adsorption of H. parasuis antigens on sheep red blood cells
(SRBCs). However, regardless of the anticoagulant used, chemical treatment of SRBCs with tannic acid
induces a stable antigen adsorption (sensitization step). The addition of 1% BSA to SRBCs washing
buffer and to antisera dilution augments IHA specificity. Tannic acid treated SRBCs combined with
thermo-resistant H. parasuis antigens increases the assay resolution. Thus, our results demonstrate an
improvement in the technique of H. parasuis serotyping that will prove valuable to understand GlĂ€sserâs
disease epidemiology and to better characterize serovars involved in outbreaksS
Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network
Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects
Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo
Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 Mâ) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<eâ€0.3 at 0.33 Gpcâ3 yrâ1 at 90\% confidence level
Ultralight vector dark matter search using data from the KAGRA O3GK run
Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)BâL gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)BâL gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM
The cross-talk between endoplasmatic reticulum stress and cytokines in pancreatic beta cell inflammation and apoptosis
La prĂ©valence de lâobĂ©sitĂ© et du diabĂšte de type 1 (DT1) sâaccroit dans le monde Ă une vitesse alarmante. Lâaugmentation du poids corporel, de la quantitĂ© dâacides gras libres (AGL) circulant et de la rĂ©sistance Ă lâinsuline peut induire un stress du rĂ©ticulum endoplasmique (RE) dans les cellules beta du pancrĂ©as, ce qui pourrait favoriser lâinflammation. Afin de tester cette hypothĂšse, nous avons exposĂ© des cellules beta Ă un lĂ©ger stress chronique du RE induit par de lâacide ciclopiazonique (ACP) ou lâAGL palmitate et les avons ensuite traitĂ©es avec une faible dose dâinterleukine 1ÎČ (IL-1ÎČ) ou de facteur de nĂ©crose tumorale (TNF-α). Lâaddition dâIL- 1ÎČ, mais pas de TNF-α, a conduit Ă lâaugmentation de la production de marqueurs pro-inflammatoires et de chimiokines. Cette diffĂ©rence de rĂ©sultat en fonction de lâexposition Ă lâIL-1ÎČ ou au TNF-α peut-ĂȘtre au moins partiellement expliquĂ©e par un usage diffĂ©rentiel du complexe de la kinase IÎșB (IKK) et de la voie du facteur nuclĂ©aire Îș-B (NF-ÎșB), menant Ă terme Ă une activation plus Ă©levĂ©e par lâIL-1ÎČ en comparaison Ă TNF-α. Lâanalyse des branches de la rĂ©ponse de la protĂ©ine dĂ©pliĂ©e impliquĂ©es a rĂ©vĂ©lĂ© que la voie de lâInositol-requiring enzyme 1 (IRE1) / X-box binding protein 1 spliced (XBP1s) est le mĂ©diateur clĂ© dans le couplage avec la rĂ©ponse inflammatoire dĂ©clenchĂ©e par lâIL-1ÎČ. En effet, le knockdown dâIRE1 ou de XBP1 a permis dâĂ©viter lâexacerbation de lâactivitĂ© du promoteur NF-ÎșB et lâexpression des gĂšnes cibles de NF-ÎșB. Les mĂ©canismes impliquĂ©s dans la rĂ©gulation XBP1-dĂ©pendante de la rĂ©ponse pro-inflammatoire sont partiellement dĂ©pendant de la modulation de la Forkhead box O1 (FoxO1). Le stress du RE et lâIL-1ÎČ participent aussi Ă un autre Ă©vĂšnement crucial dans le dĂ©veloppement du DT1, Ă savoir la mort progressive des cellules beta, qui est Ă©galement exacerbĂ©e par la combinaison ACP + IL-1ÎČ. Contrairement Ă lâinflammation, la voie IRE1/XBP1 nâest pas impliquĂ©e dans lâapoptose cellulaire induite par la combinaison dâACP et dâIL-1ÎČ. Dans ce contexte, nous suggĂ©rons que le devenir de la cellule est dĂ©cidĂ© par la balance entre les protĂ©ines Bcl-2 anti-apoptotiques et pro-apoptotiques. Ainsi, nous avons montrĂ© que le gĂšne A1 associĂ© Ă Bcl-2 (A1) est nĂ©gativement rĂ©gulĂ© par le stress du RE tandis que lâIL-1ÎČ active la protĂ©ine BH3-only Bim, aboutissant Ă une apoptose accrue des cellules beta. En conclusion, nos donnĂ©es suggĂšrent que le stress du RE est un facteur sensibilisation pour lâinduction de lâinflammation des ilots pancrĂ©atiques et de lâapoptose des cellules beta. Ceci pourrait fournir une explication mĂ©canistique Ă lâaugmentation parallĂšle observĂ©e de lâobĂ©sitĂ© infantile et de la frĂ©quence du DT1.\Doctorat en Sciences biomĂ©dicales et pharmaceutiquesinfo:eu-repo/semantics/nonPublishe
The cross-talk between endoplasmatic reticulum stress and cytokines in pancreatic beta cell inflammation and apoptosis
La prĂ©valence de lâobĂ©sitĂ© et du diabĂšte de type 1 (DT1) sâaccroit dans le monde Ă une vitesse alarmante. Lâaugmentation du poids corporel, de la quantitĂ© dâacides gras libres (AGL) circulant et de la rĂ©sistance Ă lâinsuline peut induire un stress du rĂ©ticulum endoplasmique (RE) dans les cellules beta du pancrĂ©as, ce qui pourrait favoriser lâinflammation. Afin de tester cette hypothĂšse, nous avons exposĂ© des cellules beta Ă un lĂ©ger stress chronique du RE induit par de lâacide ciclopiazonique (ACP) ou lâAGL palmitate et les avons ensuite traitĂ©es avec une faible dose dâinterleukine 1ÎČ (IL-1ÎČ) ou de facteur de nĂ©crose tumorale (TNF-α). Lâaddition dâIL- 1ÎČ, mais pas de TNF-α, a conduit Ă lâaugmentation de la production de marqueurs pro-inflammatoires et de chimiokines. Cette diffĂ©rence de rĂ©sultat en fonction de lâexposition Ă lâIL-1ÎČ ou au TNF-α peut-ĂȘtre au moins partiellement expliquĂ©e par un usage diffĂ©rentiel du complexe de la kinase IÎșB (IKK) et de la voie du facteur nuclĂ©aire Îș-B (NF-ÎșB), menant Ă terme Ă une activation plus Ă©levĂ©e par lâIL-1ÎČ en comparaison Ă TNF-α. Lâanalyse des branches de la rĂ©ponse de la protĂ©ine dĂ©pliĂ©e impliquĂ©es a rĂ©vĂ©lĂ© que la voie de lâInositol-requiring enzyme 1 (IRE1) / X-box binding protein 1 spliced (XBP1s) est le mĂ©diateur clĂ© dans le couplage avec la rĂ©ponse inflammatoire dĂ©clenchĂ©e par lâIL-1ÎČ. En effet, le knockdown dâIRE1 ou de XBP1 a permis dâĂ©viter lâexacerbation de lâactivitĂ© du promoteur NF-ÎșB et lâexpression des gĂšnes cibles de NF-ÎșB. Les mĂ©canismes impliquĂ©s dans la rĂ©gulation XBP1-dĂ©pendante de la rĂ©ponse pro-inflammatoire sont partiellement dĂ©pendant de la modulation de la Forkhead box O1 (FoxO1). Le stress du RE et lâIL-1ÎČ participent aussi Ă un autre Ă©vĂšnement crucial dans le dĂ©veloppement du DT1, Ă savoir la mort progressive des cellules beta, qui est Ă©galement exacerbĂ©e par la combinaison ACP + IL-1ÎČ. Contrairement Ă lâinflammation, la voie IRE1/XBP1 nâest pas impliquĂ©e dans lâapoptose cellulaire induite par la combinaison dâACP et dâIL-1ÎČ. Dans ce contexte, nous suggĂ©rons que le devenir de la cellule est dĂ©cidĂ© par la balance entre les protĂ©ines Bcl-2 anti-apoptotiques et pro-apoptotiques. Ainsi, nous avons montrĂ© que le gĂšne A1 associĂ© Ă Bcl-2 (A1) est nĂ©gativement rĂ©gulĂ© par le stress du RE tandis que lâIL-1ÎČ active la protĂ©ine BH3-only Bim, aboutissant Ă une apoptose accrue des cellules beta. En conclusion, nos donnĂ©es suggĂšrent que le stress du RE est un facteur sensibilisation pour lâinduction de lâinflammation des ilots pancrĂ©atiques et de lâapoptose des cellules beta. Ceci pourrait fournir une explication mĂ©canistique Ă lâaugmentation parallĂšle observĂ©e de lâobĂ©sitĂ© infantile et de la frĂ©quence du DT1.\Doctorat en Sciences biomĂ©dicales et pharmaceutiquesinfo:eu-repo/semantics/nonPublishe
Sweet Killing in Obesity and Diabetes: The Metabolic Role of the BH3-only Protein BIM.
Diabetes is a metabolic disorder affecting more than 400 million individuals and their families worldwide. The major forms of diabetes (types 1 and 2) are characterized by pancreatic ÎČ-cell dysfunction and, in some cases, loss of ÎČ-cell mass causing hyperglycemia due to absolute or relative insulin deficiency. The BCL-2 homology 3 (BH3)-only protein BIM has a wide role in apoptosis induction in cells. In this review, we describe the apoptotic mechanisms mediated by BIM activation in ÎČ cells in obesity and both forms of diabetes. We focus on molecular pathways triggered by inflammation, saturated fats, and high levels of glucose. Besides its role in cell death, BIM has been implicated in the regulation of mitochondrial oxidative phosphorylation and cellular metabolism in hepatocytes. BIM is both a key mediator of pancreatic ÎČ-cell death and hepatic insulin resistance and is thus a potential therapeutic target for novel anti-diabetogenic drugs. We consider the implications and challenges of targeting BIM in the treatment of the disease.SCOPUS: re.jinfo:eu-repo/semantics/publishe
Collateral, mutual guarantees and the entrepreneurial orientation of SMEs
Purpose: The purpose of this paper is to investigate whether guarantees characterised by different degrees of relationship lending (particularly referring to collateral and guarantees provided by Mutual Loan Guarantee Institutions) are able to convey some entrepreneurial orientation (EO) dimensions from firms to banks. Design/methodology/approach: Exploiting data from a survey of Austrian and Italian SMEs, the empirical analysis is based on a sample of 328 small business firms. To test the signalling hypothesis, the authors used logistic regressions to assess the explanatory power of EO dimensions on the presence of several types of guarantees. Findings: The analyses suggest that collateral cannot signal any EO dimension, even when controlling for the strength of the bank â firm relationship. Furthermore, SMEs are able to mitigate their financial risk through collateral only in a multiple bank â firm relationship. Lastly, innovativeness, competitive energy and aggressiveness allow SMEs to obtain external guarantees (mutual guarantees, bank guarantees and public guarantees, respectively), helpful in order to promote credit access. Research limitations/implications: The mediation role of collateral and external guarantees on EO â credit access relation should be analysed in future research. Since the role of guarantees can change among different bank lending technologies, further studies should carefully consider lenderâs characteristics. Lastly, the use of loan data in respect of the firm data can help to better separate the effect of loan and firm attributes on the collateral. Practical implications: The study suggests how managers and entrepreneurs should manage the financial risk through collateral in different situations (oneâtoâone and multiple bank â firm relationship). Furthermore, depending on the level of innovativeness, competitive energy and aggressiveness, a firm should request a specific type of external guarantees in order to increment the credit availability, to maximise the possibility of success and to improve its performance. Originality/value: To the authorsâ knowledge, this paper is the first attempt to analyse whether EO affects the request for guarantees instead of credit access. This can be helpful especially when the banks involved in the relation apply a transaction lending technology