Cardiovascular effects of sevoflurane in Holstein calves

Objective The purpose of this study was to determine the cardiovascular effects of sevoflurane in calves. Study design Prospective experimental study. Animals Six, healthy, 8–12‐week‐old Holstein calves weighing 80 ± 4.5 (mean ± SEM) kg were studied. Methods Anesthesia was induced by face‐mask administration of 7% sevoflurane in O₂. Calves tracheae were intubated, placed in right lateral recumbency, and maintained with 3.7% end‐tidal concentration sevoflurane for 30 minutes to allow catheterization of the auricular artery and placement of a Swan‐Ganz thermodilution catheter into the pulmonary artery. After instrumentation, administration of sevoflurane was temporarily discontinued until mean arterial pressure was > 100 mm Hg. Baseline values were recorded and the vaporizer output increased to administer 3.7% end‐tidal sevoflurane concentration. Ventilation was controlled to maintain normocapnia. The following were recorded at 5, 10, 15, 30 and 45 minutes after collection of baseline data and expressed as the mean value (± SEM): direct systolic, diastolic, and mean arterial blood pressures; cardiac output; mean pulmonary arterial pressure; pulmonary arterial occlusion pressure, heart rate; and pulmonary arterial temperature. Cardiac index and systemic and pulmonary vascular resistance values were calculated using standard formulae. Arterial blood gases were analyzed at baseline, and at 15 and 45 minutes. Differences from baseline values were determined using one‐way analysis of variance for repeated measures with post‐hoc differences between mean values identified using Dunnet's test (p < 0.05). Results Mean time from beginning sevoflurane administration to intubation of the trachea was 224 ± 9 seconds. The mean end‐tidal sevoflurane concentration at baseline was 0.7 (± 0.11)%. Sevoflurane anesthesia was associated with decreased arterial blood pressure at all sampling times. Mean arterial blood pressure decreased from a baseline value of 112 ± 7 mm Hg to a minimum value of 88 ± 4 mm Hg at 5 minutes. Compared with baseline, arterial pH was decreased at 15 minutes. Pulmonary arterial blood temperature was decreased at 15, 30 and 45 minutes. Arterial CO₂ tension increased from a baseline value of 43 ± 3 to 54 ± 4 mm Hg (5.7 ± 0.4 to 7.2 ± 0.3 kPa) at 15 minutes. Mean pulmonary arterial pressure was increased at 30 and 45 minutes. Pulmonary arterial occlusion pressure increased from a baseline value of 18 ± 2 to 23 ± 2 mm Hg at 45 minutes. There were no significant changes in other measured variables. All calves recovered from anesthesia uneventfully. Conclusion We conclude that sevoflurane for induction and maintenance of anesthesia was effective and reliable in these calves and that neither hypotension nor decreased cardiac output was a clinical concern. Clinical relevance Use of sevoflurane for mask induction and maintenance of anesthesia in young calves is a suitable alternative to injectable and other inhalant anesthetics.     

Clinical exercise testing in the normal Thoroughbred racehorse

To evaluate normal cardiorespiratory and metabolic responses of Thoroughbred horses to a standardised treadmill exercise test, we examined 28 horses ranging in age from 1 to 4 years. The group consisted of eight yearlings, eight 2-year-olds and twelve 3 and 4-year-olds. All horses except the yearlings were in training, and either racing or ready to race, at the time of examination. None of the horses had histories of performance problems. On the first day the horses received a full physical examination, resting electrocardiogram, upper respiratory tract endoscopy and either one or two acclimatisation runs on the treadmill. The following day they were given an exercise test on a treadmill inclined at 6 degrees (+10% slope). The test consisted of 3 min at 4 m/sec, 90 sec at 6 m/sec and 60 sec intervals at 8, 10, 11, 12 and 13 m/sec. During the last 15 sec of each step, blood samples were collected for plasma lactate determination, expired respiratory gases were obtained using an open flow mask system for measurement of oxygen uptake, and heart rate was measured using telemetry electrocardiogram. From these measurements, various derived values were calculated, which have been used by others as indices of exercise capacity. These values included: V200 (speed at HR of 200 bpm), VHRmax (speed at which horses reached maximum HR), VO2-200 (oxygen uptake at a HR of 200 bpm), VO2max (maximum oxygen uptake), VLA4 (speed at which horses reached a plasma lactate of 4 mmol/l) and HRLA4 (HR at which horses reached a plasma lactate of 4 mmol/l). The yearlings had significantly lower values than the older age groups for most of the derived values.(ABSTRACT TRUNCATED AT 250 WORDS)     

Low expression of nicotinic acetylcholine receptor subunit Mdα2 in neonicotinoid‐resistant strains of Musca domestica L.

BACKGROUND: Neonicotinoid action as well as resistance involves interaction with nicotinic acetylcholine receptors (nAChRs). In the housefly, neonicotinoid resistance also involves cytochrome P450, as indicated by bioassay with synergist as well as altered expression. In bioassay, synergism was only partial and indicated possible target‐site resistance. The nAChR α2 subunit is important in neonicotinoid toxicity to insects, and gene expression of the Mdα2 subunit was investigated in field populations and laboratory strains of neonicotinoid‐resistant and insecticide‐susceptible houseflies, Musca domestica L. The genomic sequence covering exon III–VII of Mdα2 was analysed for mutations. RESULTS: Gene expression profiling of Mdα2 revealed notable differences between neonicotinoid‐resistant and insecticide‐susceptible houseflies. On average, the neonicotinoid‐resistant field population 766b and the imidacloprid selected strain 791imi had 60% lower copy numbers of Mdα2 compared with the susceptible reference strain. Sequencing of exon III–VII of the Mdα2, encoding acetylcholine binding‐site regions and three out of four transmembrane domains, did not reveal any mutations explaining the increased neonicotinoid tolerance in the strains examined. CONCLUSION: Previous discoveries and the results of this study suggest that the neonicotinoid resistance mechanism in Danish houseflies involves both cytochrome P450 monooxygenase‐mediated detoxification and reduced expression of the nAChR subunit α2. Copyright © 2010 Society of Chemical Industry     

Effect of food enzymes on utilisation of lupin carbohydrates by broilers

1. The effects of 3 commercial enzyme products on the nutritive value of 2 lupin species were investigated with the emphasis on changes in composition of non-starch polysaccharides (NSPs) along the digestive tract. Enzyme A contained primarily cellulase, beta-glucanase and xylanase activities, enzyme B primarily hemicellulase, pentosanase and xylanase activities, and enzyme C primarily hemicellulase, pectinase and beta-glucanase activities. 2. The enzymes were added to semi-purified diets based on sorghum and casein containing 35% whole seed lupins (Lupinus angustifolius cv Gungurru or Lupinus albus cv Kiev mutant). Control diets contained no lupins. 3. Food conversion ratio (FCR), excreta moisture content and apparent metabolisable energy (AME) were affected by lupin species but not by enzyme supplementation. 4. In diets with L. angustifolius, enzyme C significantly increased digesta viscosity and increased the concentration of soluble NSPs in all sections of the intestine. 5. Digestibility of protein and NSPs in the ileum and microbial fermentation in the ileum and caeca were not affected by adding enzymes to diets containing L. angustifolius. 6. Enzyme addition to diets with L. albus did not affect digesta viscosity nor concentration of soluble NSPs but caused a significantly (P<0.05) reduced concentration of insoluble NSP in the ileum. 7. Enzyme addition to L. albus significantly (P<0.05) increased NSP digestibility in the ileum but had no effects on protein digestibility and fermentation in the ileum and caeca.     

Radar detection of the nucleus and coma of comet hyakutake

Radar observations of comet Hyakutake (C/1996 B2) made at the Goldstone Deep Space Communications Complex in California have detected echoes from the nucleus and from large grains in the inner coma. The nucleus of this bright comet was estimated to be only 2 to 3 kilometers in diameter. Models of the coma echo indicate backscatter from porous, centimeter-size grains ejected anisotropically at velocities of tens of meters per second. The radar observations suggest that a comet's activity may be a poor indicator of its size and provide evidence that large grains constitute an important component of the mass loss from a typical active comet.     

Die Bekämpfung resistenter Stubenfliegen (Musca domestica L.) mit Diazinon

Zusammenfassung In der vorliegenden Arbeit wird die Wirkung des Diazinons gegenüber resistenten und normal-sensiblen Stubenfliegen beschrieben. Es handelt sich dabei um Untersuchungsergebnisse, die im Laboratorium und in der Praxis gewonnen wurden. Die im Laboratorium für diese Experimente verwendeten resistenten Stubenfliegen gehören einem Stamm (K₁) an, der seit einigen Jahren ununterbrochen mit DDT-Wirksubstanz selektioniert wird und eine Resistenzhöhe erreicht hat, wie sie bei Wildstämmen aus dem In- und Ansland nie festgestellt werden konnte. Auch gegenüber allen anderen gebräuchlichen Insektiziden weisen diese Stubenfliegen eine mehr oder weniger stark erhöhte Widerstandsfähigkeit auf.Die praktischen Untersuchungen mit Präparaten auf der Basis von Diazinon wurden in Dörfern des Kantons Wallis durchgeführt. Eine groß angelegte Erhebung in dieser Gegend zur Abklärung des Resistenzstatus hat ergeben, daß die Stubenfliegen mit keinem der bisher bekannten Insektizide mehr wirksam bekämpft werden können.In Untersuchungen, die in zwei aufeinander folgenden Jahren durchgeführt wurden, konnte nachgewiesen werden, daß Ställe, die mit Diazinon-Spritzpulvern behandelt worden waren, während mehrerer Wochen fliegenfrei blieben. Die Stubenfliegen, die sich zur Zeit der Applikation in den Ställen befanden, wurden innert höchstens 15 Minuten in irreversible Rückenlage gebracht und starben sehr rasch.Weder beim Personal, das die Großversuche durchführte, noch bei der Lebware, die zum Teil bei der Applikation versuchshalber in den Ställen belassen wurde, konnten irgendwelche nachteiligen Folgen festgestellt werden.Diazinon läßt sich in Wohnräumen in den üblichen Formen wie Sprays, Aerosole und Rä uchermittel mit gutem Erfolg gegen Fliegen, Mücken und andere Hausinsekten anwenden. Die Direktwirkung ist nicht so ausgeprägt wie beim Pyrethrum, übertrifft aber die meisten gebräuchlichen Insektizide. Wesentlich ist, daß es bei den resistenten Stubenfliegen keine Reversibilität der Intoxikation gibt, d. h. daß die einmal in Rückenlage gebrachten Tiere sich nicht wieder erholen. Beläge von Sprays auf Basis von Diazinon haben eine mehrwöchige Dauerwirkung.Die Resultate aus Versuchen mit Altlarven resistenter und normalsensibler Stubenfliegen zeigen, daß Diazinon über eine gute larvizide Wirkung verfügt und sich zur Bekämpfung von Stubenfliegenlarven in Gruben, Dunghaufen usw. erfolgreich anwenden läßt.Die bisherigen Erfahrungen mit Diazinon lassen den Schluß zu, daß mit diesem neuen Insektizid resistente Stubenfliegen mit gutem Erfolg bekämpft werden können.Die chemischen und physikalischen Eigenschaften des Diazinons gestatten dessen Anwendung in allen für die Insektenbekämpfung gebräuchlichen Formen.Thiophosphorsäure - [2 - isopropyl - 4 - methyl-pyrimidyl - (6)] diäthylester.Gysin, H.: Un nouveau groupe de substances à activité insecticide.Gasser, R.: Expériences sur la lutte contre les araignées rouges avec de nouveaux acaricides.Grob, H.: Expériences sur la lutte contre les aphides avec de nouvelles substances à base d'uré thanes et d'esters phosphoriques.Vorträge am IIIe Congrès International de Phytopharmacie, Paris, Sept. 1952.     

预防商品鸡蛋的沙门氏菌污染

澳大利亚科学家通过观察死亡的蛤蚧卵内壳层和薄膜层,惊喜地对外宣称他们发现了沙门氏菌侵入鸡蛋的方式,但这种方式可能只是加拿大北部的特例,而且蛤蚧与商品化蛋鸡共性又很少,能否直接从蛤蚧卵推测到鸡蛋还有待考证。