RESUMO
The interactions between a virus and its host vary in space and time and are affected by the presence of molecules that alter the physiology of either the host or the virus. Determining the molecular mechanisms at the basis of these interactions is paramount for predicting the fate of bacterial and phage populations and for designing rational phage-antibiotic therapies. We study the interactions between stationary phase Burkholderia thailandensis and the phage ΦBp-AMP1. Although heterogeneous genetic resistance to phage rapidly emerges in B. thailandensis, the presence of phage enhances the efficacy of three major antibiotic classes, the quinolones, the beta-lactams and the tetracyclines, but antagonizes tetrahydrofolate synthesis inhibitors. We discovered that enhanced antibiotic efficacy is facilitated by reduced antibiotic efflux in the presence of phage. This new phage-antibiotic therapy allows for eradication of stationary phase bacteria, whilst requiring reduced antibiotic concentrations, which is crucial for treating infections in sites where it is difficult to achieve high antibiotic concentrations.
Assuntos
Antibacterianos , Bacteriófagos , Burkholderia , Antibacterianos/farmacologia , Burkholderia/efeitos dos fármacos , Regulação para BaixoRESUMO
Melioidosis is a disease that is difficult to treat due to the causative organism, Burkholderia pseudomallei being inherently antibiotic resistant and it having the ability to invade, survive, and replicate in an intracellular environment. Combination therapy approaches are routinely being evaluated in animal models with the aim of improving the level of protection and clearance of colonizing bacteria detected. In this study, a subunit vaccine layered with the antibiotic finafloxacin was evaluated in vivo against an inhalational infection with B. pseudomallei in Balb/c mice. Groups of mice vaccinated, infected, and euthanized at antibiotic initiation had a reduced bacterial load compared to those that had not been immunized. In addition, the subunit vaccine provided a synergistic effect when it was delivered with a CpG ODN and finafloxacin was initiated at 48 h post-challenge. Vaccination was also shown to improve the outcome, in a composite measure of survival and clearance. In summary, layering a subunit vaccine with the antibiotic finafloxacin is a promising therapeutic alternative for use in the treatment of B. pseudomallei infections.
Assuntos
Burkholderia pseudomallei , Melioidose , Animais , Camundongos , Camundongos Endogâmicos BALB C , Melioidose/tratamento farmacológico , Melioidose/prevenção & controle , Antibacterianos/uso terapêutico , Vacinação , Vacinas de Subunidades Antigênicas , Modelos Animais de DoençasRESUMO
We demonstrate a new technique for obtaining fission data for nuclei away from ß stability. These types of data are pertinent to the astrophysical r process, crucial to a complete understanding of the origin of the heavy elements, and for developing a predictive model of fission. These data are also important considerations for terrestrial applications related to power generation and safeguarding. Experimentally, such data are scarce due to the difficulties in producing the actinide targets of interest. The solenoidal-spectrometer technique, commonly used to study nucleon-transfer reactions in inverse kinematics, has been applied to the case of transfer-induced fission as a means to deduce the fission-barrier height, among other variables. The fission-barrier height of ^{239}U has been determined via the ^{238}U(d,pf) reaction in inverse kinematics, the results of which are consistent with existing neutron-induced fission data indicating the validity of the technique.
RESUMO
Absolute cross sections for the addition of s- and d-wave neutrons to ^{14}C and ^{14}N have been determined simultaneously via the (d,p) reaction at 10 MeV/u. The difference between the neutron and proton separation energies, ΔS, is around -20 MeV for the ^{14}C+n system and +8 MeV for ^{14}N+n. The population of the 1s_{1/2} and 0d_{5/2} orbitals for both systems is reduced by a factor of approximately 0.5 compared with the independent single-particle model, or about 0.6 when compared with the shell model. This finding strongly contrasts with results deduced from intermediate-energy knockout reactions between similar nuclei on targets of ^{9}Be and ^{12}C. The simultaneous technique used removes many systematic uncertainties.
RESUMO
A narrow near-threshold proton-emitting resonance (E_{x}=11.4 MeV, J^{π}=1/2^{+}, and Γ_{p}=4.4 keV) was directly observed in ^{11}B via proton resonance scattering. This resonance was previously inferred in the ß-delayed proton emission of the neutron halo nucleus ^{11}Be. The good agreement between both experimental results serves as a ground to confirm the existence of such exotic decay and the particular behavior of weakly bound nuclei coupled to the continuum. R-matrix analysis shows a sizable partial decay width for both, proton and α (Γ_{α}=11 keV) emission channels.
RESUMO
BACKGROUND: Monitoring oxygen delivery to the oxygenator of a heart lung machine (HLM) is typically accomplished with an O2 analyzer connected to the gas inflow line. It is assumed when the FiO2 is greater than 21% that oxygen is being delivered to the oxygenator. However, this assumption is imperfect because the connection of the inflow line to the oxygenator is downstream from the O2 analyzer. FiO2 monitoring will not alert the perfusionist if the inflow line is not actually connected to the oxygenator. Measuring the fraction of expired oxygen (FEO2) is a more reliable way of monitoring O2 delivery. METHODS: An O2 analyzer was placed on the scavenging line that is attached to the exhaust port of oxygenator (FEO2). RESULTS: Whenever the FiO2 is greater than 21%, and the inflow line is properly connected, the FEO2 exiting the oxygenator is greater than 21%. The FEO2 falls to 21% when the inflow line is not functioning. CONCLUSION: Monitoring the FEO2 is a more reliable way to verify O2 delivery to an oxygenator. An alarm can be set on the FEO2 monitor to alert the perfusionist if the FEO2 falls below a predetermined threshold so any issue with O2 delivery will always be recognized.
Assuntos
Máquina Coração-Pulmão , Oxigênio , Ponte Cardiopulmonar , Humanos , Monitorização Fisiológica , OxigenadoresRESUMO
Infection with aerosolized Francisella tularensis or Yersinia pestis can lead to lethal disease in humans if treatment is not initiated promptly. Finafloxacin is a novel fluoroquinolone which has demonstrated broad-spectrum activity against a range of bacterial species in vitro, in vivo, and in humans, activity which is superior in acidic, infection-relevant conditions. Human-equivalent doses of finafloxacin or ciprofloxacin were delivered at 24 h (representing prophylaxis) or at 72 or 38 h (representing treatment) postchallenge with F. tularensis or Y. pestis, respectively, in BALB/c mouse models. In addition, a short course of therapy (3 days) was compared to a longer course (7 days). Both therapies provided a high level of protection against both infections when administered at 24 h postchallenge, irrespective of the length of the dosing regimen; however, differences were observed when therapy was delayed. A benefit was demonstrated with finafloxacin compared to ciprofloxacin in both models when therapy was delivered later in the infection. These studies suggest that finafloxacin is an effective alternative therapeutic for the prophylaxis and treatment of inhalational infections with F. tularensis or Y. pestis.
Assuntos
Francisella tularensis , Peste , Tularemia , Animais , Fluoroquinolonas/uso terapêutico , Camundongos , Camundongos Endogâmicos BALB C , Peste/tratamento farmacológico , Peste/prevenção & controle , Tularemia/tratamento farmacológicoRESUMO
A subset of patients with COVID-19 develops a severe inflammatory response that may lead to respiratory and multiorgan failure. Effective treatment strategies to mitigate or interrupt this self-destructive inflammatory process are limited. The local anesthetic lidocaine has anti-inflammatory properties in addition to its analgesic, antiarrhythmic, and sedating effects that may be beneficial in critically ill COVID-19 patients. We report the case of a patient with COVID-19 induced severe respiratory distress who was intubated and received supportive treatment including proning and neuromuscular blockade. He developed a strong inflammatory response that we treated with an intermittent lidocaine infusion resulting in subsequent resolution. This case occurred prior to emerging data from a large dexamethasone use trial that demonstrated a survival benefit from its use in hospitalized COVID-19 patients. At the time, lidocaine was the only anti-inflammatory medication our patient received.
RESUMO
The nuclei below lead but with more than 126 neutrons are crucial to an understanding of the astrophysical r process in producing nuclei heavier than Aâ¼190. Despite their importance, the structure and properties of these nuclei remain experimentally untested as they are difficult to produce in nuclear reactions with stable beams. In a first exploration of the shell structure of this region, neutron excitations in ^{207}Hg have been probed using the neutron-adding (d,p) reaction in inverse kinematics. The radioactive beam of ^{206}Hg was delivered to the new ISOLDE Solenoidal Spectrometer at an energy above the Coulomb barrier. The spectroscopy of ^{207}Hg marks a first step in improving our understanding of the relevant structural properties of nuclei involved in a key part of the path of the r process.
RESUMO
OBJECTIVES: To assess the use of epiaortic ultrasound in contemporary cardiac surgery, as well as its impact on surgical cannulation strategy and cerebrovascular events. DESIGN: Epiaortic ultrasound data was prospectively collected in the Randomized Endovein Graft Prospective (REGROUP) trial (VA Cooperative Studies Program #588, ClinicalTrials.gov, NCT01850082), which randomized 1,150 coronary artery bypass graft patients between 2014 and 2017 to endoscopic or open-vein graft harvest. SETTING: Sixteen cardiac surgery programs within the Veterans Affairs Healthcare System with expertise at performing endoscopic vein-graft harvesting. PARTICIPANTS: Veterans Affairs patients, greater than 18 years of age, undergoing elective or urgent coronary artery bypass grafting with cardiopulmonary bypass and cardioplegic arrest with at least one planned saphenous vein graft were eligible for enrollment. INTERVENTIONS: Epiaortic ultrasound was performed by the surgeon using a high frequency (>7 MHz) ultrasound transducer. Two-dimensional images of the ascending aorta in multiple planes were acquired before aortic cannulation and cross-clamping. MEASUREMENTS AND MAIN RESULTS: Epiaortic ultrasound was performed in 34.1% (269 of 790) of patients in REGROUP. Among these patients, simple intraluminal atheroma was observed in 21.9% (59 269), and complex intraluminal atheroma comprised 2.2% (6 of 269). The aortic cannulation or cross-clamp strategy was modified based on these findings in 7.1% of cases (19 of 269). There was no difference in stroke between patients who underwent epiaortic ultrasound and those who did not (1.9% v 1.2% pâ¯=â¯0.523). CONCLUSIONS: Despite current guidelines recommending routine use of epiaortic ultrasound (IIa/B) to reduce the risk of stroke in cardiac surgery, in this contemporary trial, use remains infrequent, with significant site-to-site variability.
Assuntos
Doenças da Aorta , Placa Aterosclerótica , Aorta , Ponte de Artéria Coronária , Humanos , Placa Aterosclerótica/diagnóstico por imagem , Estudos ProspectivosRESUMO
This study investigated the in vitro activity of finafloxacin against panels of the biodefence pathogens. Broth microdilution assays were performed at neutral and acidic pH, to determine the effectiveness of the antibiotics in conditions typical of an intracellular environment. In all instances, finafloxacin demonstrated superior activity at low pH. These results highlight the importance of evaluating antimicrobial efficacy in conditions relevant to those encountered in vivo.
RESUMO
Traditionally, blood flow rates on cardiopulmonary bypass are based primarily on a formula that matches cardiac index to the patient's body surface area (BSA). However, Ranucci and associates in the Goal-Directed Perfusion Trial (GIFT) trial have shown that coupling the BSA with delivery of oxygen (DO2), known as goal-directed perfusion (GDP), may be a safer approach to determine appropriate blood flows. The objective of this study was to create a GDP reference tool that would allow perfusionists to quickly determine the lowest acceptable blood flow needed to provide a patient of any BSA with a satisfactory DO2 without the need for additional dedicated technology. We approached this problem by deriving a formula for flow (L/min), based on BSA, oxygen content of the blood, and a minimum DO2 of 280 mL·min-1m-2. A quick reference GDP chart was created based on the derived formula, requiring only the patient's BSA and hemoglobin level to determine a safe minimum flow rate. The proposed tool allows any cardiac surgery center to adopt the GDP technique, even in the absence of instantaneous DO2 monitoring equipment.
Assuntos
Procedimentos Cirúrgicos Cardíacos , Ponte Cardiopulmonar , Objetivos , Humanos , Oxigênio , Consumo de Oxigênio , PerfusãoRESUMO
A beam containing a substantial component of both the J^{π}=5^{+}, T_{1/2}=162 ns isomeric state of ^{18}F and its 1^{+}, 109.77-min ground state is utilized to study members of the ground-state rotational band in ^{19}F through the neutron transfer reaction (d,p) in inverse kinematics. The resulting spectroscopic strengths confirm the single-particle nature of the 13/2^{+} band-terminating state. The agreement between shell-model calculations using an interaction constructed within the sd shell, and our experimental results reinforces the idea of a single-particle-collective duality in the descriptions of the structure of atomic nuclei.
RESUMO
A sequence of low-energy levels in _{32}^{78}Ge_{46} has been identified with spins and parity of 2^{+}, 3^{+}, 4^{+}, 5^{+}, and 6^{+}. Decays within this band proceed strictly through ΔJ=1 transitions, unlike similar sequences in neighboring Ge and Se nuclei. Above the 2^{+} level, members of this sequence do not decay into the ground-state band. Moreover, the energy staggering of this sequence has the phase that would be expected for a γ-rigid structure. The energies and branching ratios of many of the levels are described well by shell-model calculations. However, the calculated reduced transition probabilities for the ΔJ=2 in-band transitions imply that they should have been observed, in contradiction with the experiment. Within the calculations of Davydov, Filippov, and Rostovsky for rigid-triaxial rotors with γ=30°, there are sequences of higher-spin levels connected by strong ΔJ=1 transitions which decay in the same manner as those observed experimentally, yet are calculated at too high an excitation energy.
RESUMO
Burkholderia pseudomallei is the causative agent of melioidosis, a serious disease endemic in Southeast Asia and Northern Australia. Antibiotic treatment is lengthy and relapse often occurs. Finafloxacin is a novel fluoroquinolone with increased antibacterial activity in acidic conditions in contrast to other fluoroquinolones which demonstrate reduced activity at a lower pH. Therefore, finafloxacin may have improved efficacy against B. pseudomallei, which can survive within host cells where the local pH is acidic. In vitro analysis was performed using MICs, minimal bactericidal concentrations (MBCs), time-kill assays, persister cell assays, and macrophage assays. Finafloxacin showed increased bactericidal activity at pH 5 in comparison to pH 7 and ciprofloxacin at pH 5. In vivo studies in BALB/c mice included pharmacokinetic studies to inform an appropriate dosing regimen. Finafloxacin efficacy was evaluated in an inhalational murine model of melioidosis where antibiotic treatment was initiated at 6 or 24 h postchallenge and continued for 14 days, and mice were observed for 63 days. The survival of infected mice following 14 days of treatment was 80%, 60% or 0% for treatments initiated at 6 h and 60%, 30% or 0% for treatments initiated at 24 h for finafloxacin, co-trimoxazole, or ciprofloxacin, respectively. In summary, finafloxacin has increased bactericidal activity for B. pseudomallei under acidic conditions in vitro and improves survival in a murine model of melioidosis compared with those for ciprofloxacin. Furthermore, finafloxacin improves bacteriological clearance compared with that of co-trimoxazole, suggesting it may offer an effective postexposure prophylaxis against B. pseudomallei.
Assuntos
Antibacterianos/farmacologia , Burkholderia pseudomallei/efeitos dos fármacos , Fluoroquinolonas/farmacologia , Animais , Ciprofloxacina/farmacologia , Concentração de Íons de Hidrogênio , Camundongos , Testes de Sensibilidade MicrobianaRESUMO
The apparent splitting between orbitals that are spin-orbit partners can be substantially influenced by the effects of weak binding. In particular, such effects can account for the observed decrease in separation of the neutron 1p_{3/2} and 1p_{1/2} orbitals between the ^{41}Ca and ^{35}Si isotopes. This behavior has been the subject of recent experimental and theoretical works and cited as evidence for a proton "bubble" in ^{34}Si causing an explicit weakening of the spin-orbit interaction. The results reported here suggest that the change in the separation between the 1p_{3/2} and 1p_{1/2} partners occurs dominantly because of the behavior of the energies of these 1p neutron states near zero binding.
RESUMO
The existence of ^{26}Al (t_{1/2}=7.17×10^{5} yr) in the interstellar medium provides a direct confirmation of ongoing nucleosynthesis in the Galaxy. The presence of a low-lying 0^{+} isomer (^{26}Al^{m}), however, severely complicates the astrophysical calculations. We present for the first time a study of the ^{26}Al^{m}(d,p)^{27}Al reaction using an isomeric ^{26}Al beam. The selectivity of this reaction allowed the study of â=0 transfers to T=1/2, and T=3/2 states in ^{27}Al. Mirror symmetry arguments were then used to constrain the ^{26}Al^{m}(p,γ)^{27}Si reaction rate and provide an experimentally determined upper limit of the rate for the destruction of isomeric ^{26}Al via radiative proton capture reactions, which is expected to dominate the destruction path of ^{26}Al^{m} in asymptotic giant branch stars, classical novae, and core collapse supernovae.
RESUMO
Despite the more than 1 order of magnitude difference between the measured dipole moments in ^{144}Ba and ^{146}Ba, the octupole correlations in ^{146}Ba are found to be as strong as those in ^{144}Ba with a similarly large value of B(E3;3^{-}â0^{+}) determined as 48(+21-29) W.u. The new results not only establish unambiguously the presence of a region of octupole deformation centered on these neutron-rich Ba isotopes, but also manifest the dependence of the electric dipole moments on the occupancy of different neutron orbitals in nuclei with enhanced octupole strength, as revealed by fully microscopic calculations.
RESUMO
The neutron-rich nucleus ^{144}Ba (t_{1/2}=11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers A less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced E1 transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multistep Coulomb excitation of a post-accelerated 650-MeV ^{144}Ba beam on a 1.0-mg/cm^{2} ^{208}Pb target. The measured value of the matrix element, ⟨3_{1}^{-}â¥M(E3)â¥0_{1}^{+}⟩=0.65(+17/-23) eb^{3/2}, corresponds to a reduced B(E3) transition probability of 48(+25/-34) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.
RESUMO
BACKGROUND: Childhood falls, poisonings and scalds, occurring predominantly in the home, are an important public health problem, yet there is limited evidence on the costs of these injuries to individuals and society. OBJECTIVES: To estimate National Health Service (NHS) and child and family costs of falls, poisonings and scalds. METHODS: We undertook a multicentre longitudinal study of falls, poisonings and scalds in children under 5â years old, set in acute NHS Trusts across four UK study centres. Data from parental self-reported questionnaires on health service resource use, family costs and expenditure were combined with unit cost data from published sources to calculate average cost for participants and injury mechanism. RESULTS: 344 parents completed resource use questionnaires until their child recovered from their injury or until 12â months, whichever came soonest. Most injuries were minor, with >95% recovering within 2â weeks, and 99% within 1â month of the injury. 61% emergency department (ED) attendees were not admitted, 35% admitted for ≤1â day and 4% admitted for ≥2 days. The typical healthcare cost of an admission for ≥2 days was estimated at £2000-3000, for an admission for ≤1â day was £700-1000 and for an ED attendance without admission was £100-180. Family costs were considerable and varied across injury mechanisms. Of all injuries, scalds accrued highest healthcare and family costs. CONCLUSIONS: Falls, poisonings and scalds incur considerable short-term healthcare and family costs. These data can inform injury prevention policy and commissioning of preventive services.