Effects of two fractions of inspired oxygen on lung aeration and gas exchange in cats under inhalant anaesthesia

ObjectiveTo compare the effects of two fractions of inspired oxygen (FiO₂) (0.4 and 1) on lung aeration and gas exchange during general anaesthesia in cats.Study designRandomized, blinded, controlled study.AnimalsThirty healthy, mixed breed, client owned female cats.Materials and methodsCats were premedicated intramuscularly with acepromazine (0.03 mg kg^?1) and medetomidine (0.015 mg kg^?1). Anaesthesia was induced with propofol (5 mg kg^?1) and, after orotracheal intubation, maintained with isoflurane carried by either 100% oxygen (G100, n = 15) or an oxygen-air mixture with 40% oxygen (G40, n = 15). All cats were placed in dorsal recumbency and breathed spontaneously throughout the entire procedure. Following surgery (ovariectomy), a spiral computed tomography (CT) of the thorax was performed, arterial oxygen (PaO₂) and carbon dioxide (PaCO₂) tensions were measured and alveolar-arterial gradient of oxygen [P(A-a)O₂] calculated. The CT images were analysed for lung aeration by the analysis of radiograph attenuations (Hounsfield units, HU), according to the following classification: hyperinflated area (-1000 to -900 HU), normally aerated area (-900 to -500 HU), poorly aerated area (-500 to -100 HU) and non-aerated area (-100 to +100 HU). The groups were compared using one-way anova.ResultsCompared to G100, the normally-aerated lung area was significantly greater and the poorly-aerated and non-aerated areas were significantly smaller in G40. PaCO₂ was similar in both groups. PaO₂ and P(A-a)O₂ were significantly higher in G100. In both groups, pulmonary atelectasis developed preferentially in the caudal lung fields.ConclusionIn cats anaesthetised with isoflurane, the administration of an FiO₂ of >0.9 significantly impaired lung aeration and gas exchange as compared to an FiO₂ of 0.4.Clinical relevanceAn FiO₂ of 0.4 may better preserve lung aeration and gas exchange in anaesthetised spontaneously breathing cats but monitoring is essential to ensure oxygenation is adequate.     

Flash flood simulation and valve behavior of Mytilus galloprovincialis measured with Hall sensors

Mussels close their shell as a protective strategy and the quantification of this behavioral marker may represent an alarm signal when they are exposed to environmental stressors. In the present study, we investigated the ability of the Mediterranean mussel Mytilus galloprovincialis to recover and then the resilience or inertia of valve activity after a pulsing exposition to diverse levels of salinity (5, 10, 20, and 35 PSU as reference value). The trial simulated an event of drastic and sudden reduction of seawater salinity thus mimicking an event of flash flood from intense rain. Valve gaping and movements were measured in continuous cycle for 10 days using a customized magneto-electric device which uses Hall sensors. Results showed that under normal conditions of salinity (35 PSU), the general pattern of valve movements was a continuously open state with sporadic spikes indicating a closing motion. At salinity of 5, PSU mussels reacted by closing their valves, leading to a 77% mortality on the 4th day. At salinity of 10, PSU animals were observed with closed valves for the entire duration of the exposure and no mortality occurred, they showed a significant reduction in the valve activity once the reference value of salinity was re-established. In contrast, salinity of 20 PSU did not trigger a significant behavioral response. Interestingly, there no define rhythms of valve movements were recorded during salinity challenges.     

Long-term Electrocardiography Recording with Holter Monitoring in 15 Donkeys

The heart rates (HR) and rhythms of 15 healthy donkeys of various ages, both sexes, and various breeds were analyzed throughout 24-hour Holter monitoring. The animals were evaluated at rest in their daily environment without the presence of investigators causing stress, using a three-channel digital Holter recorder. Analysis revealed a maximal HR range from 62.5 to 93.7 beats/min (mean, 72.50 ± 7.51 beats/min), whereas the minimal HR ranged from 29.7 to 42.2 beats/min (mean, 34.90 ± 4.22 beats/min). The daily mean HR was 47.55 ± 3.70 beats/min. The daytime mean HR was 49.39 ± 2.77 beats/min, whereas the night time rate was 46.22 ± 4.38 beats/min. Sinus bradycardia and sinus tachycardia were detected in 7 and 10 of 15 studied donkeys, respectively. Cardiac dysrhythmias due to high vagal tone such as sinoatrial heart block and second-degree atrioventricular heart block were occasionally recorded in 1 and 3 donkeys, respectively. A higher mean HR and fewer cardiac dysrhythmias were observed in donkeys than in horses and ponies at rest. These findings could be justified by differences in the autonomic nervous system tone.     

Salmonella enterica serovar Choleraesuis derivatives harbouring deletions in rpoS and phoP regulatory genes are attenuated in pigs, and survive and multiply in porcine intestinal macrophages and fibroblasts, respectively

Live attenuated Salmonella enterica strains have been extensively studied as potential vectors for the oral delivery of heterologous antigens. Due to its ability to target immune cells, its specific mechanism for crossing the intestinal barrier, and its swine-restricted tropism, S. enterica subspecies enterica serovar Choleraesuis (S. Choleraesuis) has attracted a great deal of interest for the production of bacterial-based oral carriers specifically adapted to swine. In this study, two mutants of S. Choleraesuis were constructed and their attenuation and intracellular fate analysed with the purpose of engineering new attenuated live strains with improved properties as oral vaccine carriers. Those strains harboured a specific deletion either within the phoP or rpoS genes, which encode virulence-related regulators in S. Typhimurium. In comparison to the wild-type parental S. Choleraesuis, the mutant strains, especially DeltaphoP, were extremely low in virulence in the murine model and in the natural host, the pig. Moreover, when compared with a commercial live vaccine strain, SC-54, the two mutants showed a higher level of attenuation in mice and DeltaphoP also in pigs. In addition, DeltarpoS and DeltaphoP presented a proliferation and survival phenotype within swine intestinal primary fibroblast and macrophage cell cultures, respectively. Collectively, the present results indicate that the DeltarpoS and DeltaphoP strains of S. Choleraesuis gather adequate features to be potential candidates for vaccine vectors for the specific delivery of heterologous antigens adapted to pigs.     

Application-Oriented Marine Isomerases in Biocatalysis

The class EC 5.xx, a group of enzymes that interconvert optical, geometric, or positional isomers are interesting biocatalysts for the synthesis of pharmaceuticals and pharmaceutical intermediates. This class, named “isomerases,” can transform cheap biomolecules into expensive isomers with suitable stereochemistry useful in synthetic medicinal chemistry, and interesting cases of production of l-ribose, d-psicose, lactulose, and d-phenylalanine are known. However, in two published reports about potential biocatalysts of marine origin, isomerases are hardly mentioned. Therefore, it is of interest to deepen the knowledge of these biocatalysts from the marine environment with this specialized in-depth analysis conducted using a literature search without time limit constraints. In this review, the focus is dedicated mainly to example applications in biocatalysis that are not numerous confirming the general view previously reported. However, from this overall literature analysis, curiosity-driven scientific interest for marine isomerases seems to have been long-standing. However, the major fields in which application examples are framed are placed at the cutting edge of current biotechnological development. Since these enzymes can offer properties of industrial interest, this will act as a promoter for future studies of marine-originating isomerases in applied biocatalysis.     

Use of sewage sludge in silvopastoral systems under Pinus radiata D. Don: soil,tree growth,and pasture production

Agroforestry Systems - Short-term production in silvopastoral systems is often limited due to inappropriate soil-fertility management. Sewage sludge fertilisation could enhance productivity of...     

Non-thermal Plasma as an Innovative Option for the Abatement of Volatile Organic Compounds: a Review

Volatile organic compounds (VOCs) cause global and local impacts, resulting in environmental, health, and economic adverse effects. Industrial and waste management activities are the main anthropogenic stationary sources of VOCs in the atmosphere. The traditional technologies for the treatment of VOC-contaminated air present several limitations when treating effluents with low VOC concentrations, high airflow rate, and with compounds with low solubility in water. However, a novel technology, based on non-thermal plasmas (NTPs) and catalysis, has shown promising results in air purification. In this framework, after an initial overview on NTP-catalysis principles, this review presents and discusses 20 recent papers, with a threefold purpose: evaluating the most recent applications of NTP and NTP-catalysis reactors to the treatment of air-VOC mixtures, analyzing all the parameters that may influence the abatement efficiency and the by-product formation, and providing the reader with insights into the choice of the preferable configurations to use, based on the effluent type and the destination of the treated air. As a result of this review, NTPs may represent a promising option for indoor air treatment, especially because of the lower expected byproduct formation when treating low-concentrated VOC mixtures with relatively low air flow rates. If the target is the abatement of higher VOC concentrations, the higher energy efficiency obtainable in such conditions makes NTP-catalysis a cost-effective option for industrial applications. In addition, the formation of simpler and more soluble by-products makes NTPs a suitable technology for air pretreatment upstream of water-based removal technologies, such as absorption columns and biofilters.     

Effect of the number of intercrosses on grain yield in basic rice synthetic populations

The effect of 0, 1, 2, 3 and 4 intercross cycles using genetic male sterility on the mean yield and genetic variability of the CNA 5 irrigated rice synthetic population was assessed studying 300 S_0:2 (1998/99) and S_0:3 (1999/00) families grown in two locations (Lambari, MG and Goianira, GO). Each intercross was investigated using a 8 × 8 triple lattice design experiment containing 60 families and four control cultivars. Five experiments were carried out per location and generation, totaling 20 experiments. Individual, combined over locations, combined over generations and combined over locations and generations analyses of variance were performed. Linear regression equations were fitted to data of each location and generation as well as, genetic and phenotypic parameters were estimated. An average increase of 3.91% in grain yield was obtained with the increase in the number of intercrosses. However, when genetic gains obtained from selection of the five and ten highest yielding families were considered, negative b estimates were always obtained, suggesting a tendency of gain increase reduction with the increase in the number of intercrosses. This was confirmed by the analysis of the means of the best families, since increases in the number of intercrosses did not result in selection of families with greater mean grain yield. The estimates of the genetic variances and heritabilities did not suggest an increase in genetic variability with the increase in intercross cycles. Therefore, carrying out intercrosses on the base population did not improve the results of the irrigated rice recurrent selection program. This revised version was published online in August 2006 with corrections to the Cover Date.     

Implications of early selection for grain colour on iron and zinc content and productivity of common bean

Brazilian consumers prefer beans of the beige grain colour. Common beans help supply dietary requirements for iron and zinc. The objectives of this study were (i) to determine whether early selection for grain colour affects the iron and zinc content and the grain yield in common beans and (ii) if an association between these characteristics was found, to obtain lines of carioca‐type grains with a high iron and zinc content and good grain yield. We evaluated 96 F_3:4, F_3:5 and F_3:6 progeny at two locations for iron and zinc content and grain yield. We selected 48 progeny for grain colour and chose 48 others at random. We found that early selection for grain colour does not affect the zinc content and grain yield. A positive and high association was found between iron and zinc content, and both iron and zinc content were slightly negatively correlated with grain yield. It is possible to obtain common bean lines combining a high iron and zinc content with good grain yield as long as a selection index is used.