63 research outputs found
Oxygen reserve index to predict oxygen status in anaesthetized dogs
No full textOxygen reserve index (ORi) is a non-invasive continuous parameter ranging from 0 to 1 that positively correlates with arterial oxygen content (PaO2) between 100-200 mmHg in humans. This prospective study investigated the relationship of ORi with PaO2, and its use to predict oxygen content in dogs.
In 21 anaesthetised mechanically ventilated healthy dogs undergoing elective procedures, PaO2 was measured by a blood gas analyser and at the time of blood collection the ORi recorded by Masimo multi-wavelength pulse CO-oximeter. Pearson coefficient (r) was used to assess the correlation between ORi and PaO2. To identify if factors known to affect the pulse oximeter reading, such as the weight, local perfusion, pH, PaCO2, and temperature, influenced ORi measurements, paired data were fitted in a linear model and the correlation between the model residuals and the confounders was calculated. Youden index was used to identify the ORi value that predicted PaO2 ≥ 150 mmHg with the highest sensitivity and specificity.
A total of 51 paired measurements of ORi and PaO2 were collected, and a moderate positive correlation (r = 0.6) was found. Plethysmographic curve appeared to influence the accuracy of ORi rather than the perfusion index. Only body weight mildly affected ORi measurements (r = 0.48, p < 0.05). An ORi ≥ 0.48 indicated a PaO2 ≥ 150 mmHg with as sensitivity of 87%.
The oxygen reserve index may be used to titrate oxygen administration in anaesthetised dogs, although it does not replace blood gas analysis for arterial oxygen content measurement
Constraining the Accretion Geometry of the Intermediate Polar EX Hya Using NuSTAR, Swift, and Chandra Observations
No full textIn magnetically accreting white dwarfs, the height above the white dwarf surface where the standing shock is formed is intimately related with the accretion rate and the white dwarf mass. However, it is difficult to measure. We obtained new data with NuSTAR and Swift that, together with archival Chandra data, allow us to constrain the height of the shock in the intermediate polar EX Hya. We conclude that the shock has to form at least at a distance of about one white dwarf radius from the surface in order to explain the weak Fe Kα 6.4 keV line, the absence of a reflection hump in the high-energy continuum, and the energy dependence of the white dwarf spin pulsed fraction. Additionally, the NuSTAR data allowed us to measure the true, uncontaminated hard X-ray (12-40 keV) flux, whose measurement was contaminated by the nearby galaxy cluster Abell 3528 in non-imaging X-ray instruments.Fil: Luna, Gerardo Juan Manuel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mukai, K.. National Aeronautics and Space Administration; Estados UnidosFil: Orio, M.. Università di Padova; ItaliaFil: Zemko, P.. Università di Padova; Itali
The ability of oxygen reserve index to detect mild hyperoxemia in mechanically ventilated dogs: a preliminary study
No full textIntroduction:Mild hyperoxemia in humans could be detected with the oxygen reserve index (ORi) for arterial partial pressure of oxygen (PaO2) between 100 and 200 mmHg. This study evaluated the correlation of ORi with PaO2 and its ability to detect mild hyperoxemia in dogs.
Methods:This prospective observational study enrolled 23 adult anesthetized dogs undergoing elective procedures. The animals were ventilated under pressure-control ventilation with a peak inspiratory pressure of 10–12cm H2O and a respiratory rate adjusted to maintain normocapnia. Simultaneous measurements of ORi and PaO2 were collected, with a multi-wavelength pulse co-oximeter with a probe applied to the dog’s tongue, and a blood gas analyzer, respectively. Pearson correlation coefficient (r) was calculated between simultaneous measurements of ORi and PaO2. Youden index was used toidentify the ORi cutoff values predicting PaO2 hyperoxia thresholds ≥110, ≥120, ≥130, ≥140, and ≥150 mm Hg with the highest sensitivity and specificity. Diagnostic performances of ORi to detect the same hyperoxia thresholds were estimated using the area under the receiver operating characteristic curve (AUROC).The effects of perfusion index (PI),body temperature, arterial blood pH, partial pressure of carbon dioxide (pCO2), lactatemia, and hemoglobin on AUROC were evaluated.
Results: A total of 56 paired measurements of ORi and PaO2 were collected. Mean PaO2 value was 148.8 ±32.48 mm Hg and mean hemoglobin was 12.58±1.84 g/dL. A moderate positive correlation (r=0.53,P<0.001) between ORi and PaO2 was found. The ORicutoff value with the highest sensitivity (91%) was 0.3, indicating PaO2 ≥120 mm Hg, with 70% specificity and AUROC=0.84 (95%CI=0.68–1.01). The ORi value cutoff with the highest specificity (86%) was 0.6, indicating PaO2≥140 mm Hg, with 60% sensitivity and AUROC=0.79 (95% CI=0.67–0.91). The AUROCs of ORito detect hyperoxia thresholds tended to increase with decreasing blood pH, PI, and lactatemia and with increasing pCO2 and temperature, while hemoglobin did not affect diagnostic performance of ORi.
Conclusions: ORi may detect mild hyperoxemia with PaO2 between120 and 140 mm Hg and limit excessive hyperoxia in mechanically ventilated dogs, although it does not replace blood gas analysis for assessment of oxygenation
Markers of biological age in dogs
No full textAs human life expectancy continues to rise, ageing and age-related diseases have become critical societal challenges, driving extensive research across genetics, molecular biology, biochemistry, and behavioral sciences. In this context, domestic dogs (Canis lupus familiaris) offer a unique model for ageing research due to their shared environmental exposures with humans, diverse genetic profiles, and relatively short lifespans. This review aims to identify potential biomarkers of ageing in dogs, facilitating a deeper understanding of age-related mechanisms and supporting the evaluation of interventions designed to promote healthy ageing. We present a research of peer-reviewed literature on age-related variations of various parameters across multiple biological systems, including epigenetic, telomere, immune, metabolic, and cognitive markers in dogs. Our findings highlight several robust biomarkers, such as DNA methylation-based epigenetic clocks, telomere attrition, CD4+/CD8+ T-cell ratio, hematological markers (e.g., globulin levels), and cognitive function scores. These biomarkers demonstrate strong parallels with human ageing processes, particularly concerning genomic and epigenetic alterations. However, challenges remain, including breed-specific variability, body size differences, and inconsistent evidence regarding inflammageing markers, such as pro-inflammatory cytokines. Despite these limitations, indicators of chronic inflammation (e.g., anemia of chronic disease and elevated globulins) are evident in older dogs. Future research directions include the standardization of biomarker protocols for dogs, the development of longitudinal studies to track dynamic age-related changes, and further exploration of emerging biomarkers, such as those related to microbiome composition and oxidative stress
Multimission observations of the old nova GK Per during the 2015 outburst
No full textGK Per, a classical nova of 1901, is thought to undergo variable mass accretion on to a magnetized white dwarf (WD) in an intermediate polar system (IP). We organized a multi-mission observational campaign in the X-ray and ultraviolet (UV) energy ranges during its dwarf nova (DN) outburst in 2015 March-April. Comparing data from quiescence and near outburst, we have found that the maximum plasma temperature decreased from about 26 to 16.2+/-0.4 keV. This is consistent with the previously proposed scenario of increase in mass accretion rate while the inner radius of the magnetically disrupted accretion disc shrinks, thereby lowering the shock temperature. A NuSTAR observation also revealed a high-amplitude WD spin modulation of the very hard X-rays with a single-peaked profile, suggesting an obscuration of the lower accretion pole and an extended shock region on the WD surface. The X-ray spectrum of GK Per measured with the Swift X-Ray Telescope varied on time-scales of days and also showed a gradual increase of the soft X-ray flux below 2 keV, accompanied by a decrease of the hard flux above 2 keV. In the Chandra observation with the High Energy Transmission Gratings, we detected prominent emission lines, especially of Ne, Mg and Si, where the ratios of H-like to He-like transition for each element indicate a much lower temperature than the underlying continuum. We suggest that the X-ray emission in the 0.8-2 keV range originates from the magnetospheric boundary.Fil: Zemko, P.. Universita Di Padova; ItaliaFil: Orio, M.. Universita Di Padova; ItaliaFil: Luna, Gerardo Juan Manuel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Mukai, K.. National Aeronautics And Space Administration; Estados UnidosFil: Evans, P. A.. University of Leicester; Reino UnidoFil: Bianchini, A.. Universita Di Padova; Itali
CXO J004318.8+412016*A steady supersoft X-ray source in M 31
No full textWe obtained an optical spectrum of a star we identify as the optical counterpart of the M31 Chandra source CXO J004318.8+412016, because of prominent emission lines of the Balmer series, of neutral helium, and a He II line at 4686 Å. The continuum energy distribution and the spectral characteristics demonstrate the presence of a red giant of K or earlier spectral type, so we concluded that the binary is likely to be a symbiotic system. CXO J004318.8+412016 has been observed in X-rays as a luminous supersoft source (SSS) since 1979, with effective temperature exceeding 40 eV and variable X-ray luminosity, oscillating between a few times 1035 erg s-1 and a few times 1037 erg s-1 in the space of a few weeks. The optical, infrared and ultraviolet colours of the optical object are consistent with an an accretion disc around a compact object companion, which may be either a white dwarf or a black hole, depending on the system parameters. If the origin of the luminous supersoft X-rays is the atmosphere of a white dwarf that is burning hydrogen in shell, it is as hot and luminous as post-thermonuclear flash novae, yet no major optical outburst has ever been observed, suggesting that the white dwarf is very massive (m ≥ 1.2 M⊙) and it is accreting and burning at the high rate m > 10-8 M⊙ yr-1 expected for Type Ia supernovae progenitors. In this case, the X-ray variability may be due to a very short recurrence time of only mildly degenerate thermonuclear flashes.Fil: Orio, Marina. Osservatorio Astronomico Di Padova; Italia. University of Wisconsin; Estados UnidosFil: Luna, Gerardo Juan Manuel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina. Universidad de Buenos Aires; ArgentinaFil: Kotulla, R.. University of Wisconsin; Estados UnidosFil: Gallager, J. S.. University of Wisconsin; Estados UnidosFil: Zampieri, L.. Osservatorio Astronomico Di Padova; ItaliaFil: Mikolajewska, J.. Nicolaus Copernicus Astronomical Center Of The Polish Academy Of Sciences; PoloniaFil: Harbeck, D.. Wiyn Observatory; Estados UnidosFil: Bianchini, A.. Università di Padova; ItaliaFil: Chiosi, E.. Università di Padova; ItaliaFil: Della Valle, M.. Osservatorio Astronomico Di Capodimonte; ItaliaFil: de Martino, D.. Osservatorio Astronomico Di Capodimonte; ItaliaFil: Kaur, A.. Clemson University; Estados UnidosFil: Mapelli, M.. Osservatorio di Padova; ItaliaFil: Munari, U.. Osservatorio di Padova; ItaliaFil: Odendaal, A.. University of the Free State; SudáfricaFil: Trinchieri, G.. Osservatorio Astronomico di Brera; ItaliaFil: Wade, J.. University of Wisconsin; Estados UnidosFil: Zemko, P.. Università di Padova; Itali
Optical observations of ‘hot’ novae returning to quiescence
No full textWe have monitored the return to quiescence of novae previously observed in outburst as supersoft X-ray sources, using optical photometry of the intermediate polar (IP) V4743 Sgr and the candidate IP V2491 Cyg, and optical spectroscopy of these two and seven other systems. Our sample includes classical and recurrent novae, short-period (few hours), intermediate-period (1-2days) and long-period (symbiotic) binaries. The light-curves of V4743 Sgr and V2491 Cyg present clear periodic modulations. For V4743 Sgr, the modulation occurs with the beat of the rotational and orbital periods. If the period measured for V2491 Cyg is also the beat of these two periods, the orbital period should be almost 17 h. The recurrent nova T Pyx already shows fragmentation of the nebular shell less than 3 yr after outburst. While this nova still had strong [O III] at this post-outburst epoch, these lines had faded after 3 to 7 yr in all the others. We did not find any difference in the ratio of equivalent widths of high-ionization/excitation lines to that of the Hβ line in novae with short and long orbital periods, indicating that irradiation does not trigger a high mass-transfer rate \dot{m} from secondaries with small orbital separation. An important difference between the spectra of RS Oph and V3890 Sgr and those of many symbiotic persistent supersoft sources is the absence of forbidden coronal lines. In combination with the X-ray turn-off, we interpret this as an indication that mass transfer in symbiotic recurrent novae is intermittent
X-Ray Observations of VY Scl-Type Nova-Like Binaries in the High and Low State
No full textFour VY Scl-type nova-like systems were observed in X-rays both during the low and the high optical states. They are BZ Cam, MV Lyr, TT Ari, and V794 Aql. Using archival ROSAT, Swift and SUZAKU observations we found that the X-ray flux for BZ Cam is higher during the low state, but there is no supersoft X-ray source (SSS) that would indicate the thermonuclear burning predicted in a previous article. The X-ray flux is lower by a factor 2–10 in the low than the high state in other systems, and does not reflect the drop in ˙M inferred from optical and UV data. The best fit model for the X-ray spectra is a collisionally ionized plasma model. The X-ray flux may originate in a shocked wind or in accretion onto polar caps in intermediate polar systems that continues even during the low state
Metatanais Shiino 1952
No full textGenus <i>Metatanais</i> Shiino, 1952 <p> <b>Diagnoses.</b> See Shiino (1952: new genus and diagnosis); Błażewicz-Paszkowycz & Zemko (2009: genus diagnosis and remarks); and Bird (2015: remarks on genus, including subfamilial diagnosis). <b>Type species.</b> <i>Metatanais cylindricus</i> Shiino, 1952.</p> <p> <b>Composition (four species).</b> <i>M</i>. <i>bipunctatus</i>; Błażewicz-Paszkowycz & Zemko, 2009; <i>M</i>. <i>cylindricus</i>; <i>M</i>. <i>progenitor</i> Bird, 2015; <i>M</i>. <i>spinipropodus</i> <b>sp. nov.</b></p>Published as part of <i>Morales-Núñez, Andrés G., Pelleteri, Sara & Heard, Richard W., 2016, Two new paratanaid Tanaidacea (Crustacea: Malacostraca: Peracarida) from the Hawaiian Islands, with illustrated taxonomic keys, pp. 467-492 in Zootaxa 4150 (4)</i> on page 468, DOI: 10.11646/zootaxa.4150.4.5, <a href="http://zenodo.org/record/272108">http://zenodo.org/record/272108</a>
X-Ray Observations of VY Scl-Type Nova-Like Binaries in the High and Low State
No full textFour VY Scl-type nova-like systems were observed in X-rays both during the low and the high optical states. They are BZ Cam, MV Lyr, TT Ari, and V794 Aql. Using archival ROSAT, Swift and SUZAKU observations we found that the X-ray flux for BZ Cam is higher during the low state, but there is no supersoft X-ray source (SSS) that would indicate the thermonuclear burning predicted in a previous article. The X-ray flux is lower by a factor 2–10 in the low than the high state in other systems, and does not reflect the drop in ˙M inferred from optical and UV data. The best fit model for the X-ray spectra is a collisionally ionized plasma model. The X-ray flux may originate in a shocked wind or in accretion onto polar caps in intermediate polar systems that continues even during the low state
- …
