Clinical exercise testing in the normal Thoroughbred racehorse   总被引：1，自引：0，他引：1  

RJ ROSE  DK HENDRICKSON  PK KNIGHT 《Australian veterinary journal》1990,67(10):345-348

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)  相似文献   

Cross-section studies on the distribution of resistant bacteria among animals in 1975     

D Günther  E Bulling  J Brauer 《Zentralblatt für Veterin?rmedizin. Reihe B. Journal of veterinary medicine. Series B》1977,24(9):698-707

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Cardiovascular effects of sevoflurane in Holstein calves     

SA Greene DVM  MS  DiplomateACVA    RD Keegan DVM  DiplomateACVA    RA Valdez† DVM  & DK Knowles† DVM  PhD 《Veterinary anaesthesia and analgesia》2002,29(2):59-63

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.  相似文献   

Barbiturate intoxication in two dogs confirmed by toxicological urinalysis     

C. Brauer    A. Tipold    H. Desel    V. M. Stein 《The Journal of small animal practice》2009,50(8):423-425

Two dogs were presented within 24 hours to the Department of Small Animal Medicine and Surgery at the University of Veterinary Medicine Hannover for investigation of the sudden onset of neurological abnormalities following a walk in the same park. One dog was observed ingesting a piece of meat. Analysis of urine by gas chromatography-mass spectrometry from each of the dogs identified the presence of barbiturates. Both dogs recovered with supportive treatment. This is the first report to describe the use of toxicological urinalysis with gas chromatography-mass spectrometry for the diagnosis of barbiturate intoxication in dogs.  相似文献   

Enhanced atrazine degradation is widespread across the United States          下载免费PDF全文

Thomas C Mueller  Ethan T Parker  Larry Steckel  Sharon A Clay  Micheal DK Owen  William S Curran  Randall Currie  Robert Scott  Christy Sprague  Daniel O Stephenson  Donnie K Miller  Eric P Prostko  W James Grichar  James Martin  L Jason Kruz  Kevin Bradley  Mark L Bernards  Peter Dotray  Stevan Knezevic  Vince Davis  Robert Klein 《Pest management science》2017,73(9):1953-1961

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

Mette DK Markussen  Michael Kristensen 《Pest management science》2010,66(11):1257-1262

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  相似文献   

An insect growth inhibitor--lufenuron--enhances albendazole activity against hydatid cyst     

Breijo M  Isnardi F  Brauer M  Schenker R  Ferrari M  Ferreira AM 《Veterinary parasitology》2011,181(2-4):341-344

The aim of this work was to evaluate the potential of lufenuron, a benzylphenylurea with ability to interfere with the formation of insect exoskeleton, as a therapeutic drug for larval echinococcosis (hydatid disease). For this purpose lufenuron, alone or in combination with albendazole, was administered to CD1 mice bearing Echinococcus granulosus hydatid cysts in the peritoneal cavity. Neither of the drugs alone was able to exert parasiticidal effects. However, in combination with albendazole, lufenuron reduced the growth of cysts (30-40% in cyst diameter respect to control, p<0.05). This effect was associated with ultrastructural alterations of the hydatid cyst wall and a reduction of the content of myo-inositol-hexakisphosphate, the major component of the electron dense granules of the laminated layer. Overall, this work provides evidence that lufenuron could represent a useful compound for the use in chemotherapy against larval echinococcosis, by enhancing albendazole parasiticidal activity.  相似文献   

Aluminum inhibition of NADH‐linked electron transfer by corn root plasma membranes     

Matthew Loper  David Brauer  Deidre Patterson  Shu‐I Tu 《Journal of plant nutrition》2013,36(3):507-514

Vesicles enriched in right‐side‐out plasma membranes were isolated from corn roots by a modified two‐phase partition method. Using reduced nicotinamide adenine dinucleotide as electron donor, isolated vesicles were capable of reducing both ferricyanide and oxygen. At pH 6.0, the presence of Al inhibited both reduction processes to a similar extent. This result indicates that these two reduction processes share at least one common step that is sensitive to Al. Inhibition was not associated with a change in the structure of the membrane domain, as revealed by fluorescence polarization of membrane incorporated probes. These results are the first indications that the electron transfer processes of plasma membranes are sensitive to the presence of Al.  相似文献   

Potassium inhibition of calcium and magnesium accumulation in roots of intact maize seedlings     

David Brauer 《Journal of plant nutrition》2013,36(5):709-716

The effects of solution potassium (K) on the accumulation of magnesium (Mg) and calcium (Ca) in roots was assessed with 7‐day‐old corn (Zea mays L.) seedlings. Root accumulation of Ca and Mg was studied in replacement type experiments, i.e. the ratio of Ca to Mg was altered but the concentration of Ca plus Mg was kept constant at 2 mM. Concentrations of Ca in the tissue after 12 h exceeded that of Mg, except when Mg comprised over 85% of the divalent cations in the uptake solution. The addition of 0.1 mM K to the Uptake solutions significantly altered the accumulation of Ca and Mg. The concentration of Mg was affected more than that of Ca. The relative effects of solution K on Mg and Ca accumulation in roots could be explained by comparing the relative acid‐base characteristics of the metals.  相似文献   

Do farmers manage weeds on owned and rented land differently? Evidence from US corn and soybean farms     

George B Frisvold  Joshua Albright  David E Ervin  Micheal DK Owen  Jason K Norsworthy  Katherine E Dentzman  Terrance M Hurley  Raymond A Jussaume  Jeffrey L Gunsolus  Wesley Everman 《Pest management science》2020,76(6):2030-2039

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