Effects of infectious bovine rhinotracheitis virus infection on bovine airway reactivity.          下载免费PDF全文

P D Conlon  P O Ogunbiyi  R J Perron    P Eyre 《Canadian journal of veterinary research》1987,51(3):345-349

The response of isolated tracheal and bronchial strips to isoproterenol in vitro was studied in eleven male Jersey calves. Clinical, microbiological and pathological evaluations of the calves were carried out. In calves exposed once or twice to infectious bovine rhinotracheitis virus, the relaxation threshold of the trachealis muscle to isoproterenol was significantly (p less than 0.05) impaired (threshold 5.0 X 10(-7) M, single exposure and 1.0 X 10(-7) M, double exposure), when compared with uninfected controls (threshold 1.0 X 10(-8) M). Single infection significantly impaired tracheal relaxation to isoproterenol doses from 1.0 X 10(-7) to 5.0 X 10(-4) M, and double infection significantly impaired tissue responses at drug doses from 1.0 X 10(-7) to 1 X 10(-4) M. Bronchial relaxation threshold was not significantly inhibited (p less than 0.05) in singly infected or doubly infected animals (threshold 5.0 X 10(-8) M and 1.0 X 10(-8) M, respectively), when compared with uninfected controls (threshold 1.0 X 10(-9) M). Single infection significantly impaired bronchial relaxation at isoproterenol doses from 1.0 X 10(-7) M to 5.0 X 10(-6) M while double infection significantly impaired relaxation only at 5.0 X 10(-7) M. The disruption of normal homeostatic bronchodilatory mechanisms may predispose animals infected with infectious bovine rhinotracheitis virus to secondary bacterial infections due to excessive airway constriction and subsequent compromise of lung defenses.  相似文献   

Using GIS to measure changes in the temporal and spatial dynamics of forestland: experiences from north-west Spain   总被引：2，自引：0，他引：2  

Marey Perez  MF; Rodriguez Vicente  V; Crecente Maseda  R 《Forestry》2006,79(4):409-423

Forestry variables are usually calculated at a forest managementunit scale. However, a region's forestry sector is affectedby various other factors that interact over space and time,many of which are not directly associated to silvicultural activitiesbut nonetheless play an important part in its development froma socio-economic or environmental point of view. To understanda region's forestry dynamics, and especially to predict itsfuture tendencies, we must include all the necessary variablesin a single database, calculated for spatial units that arestable over time and adequate for planning purposes. In ourstudy, we developed a Forest Geographic Information System forGalicia called ‘SIFGa’. We used it to examine 310variables describing the environment, population tendencies,land tenure and forest management in the Spanish autonomousregion of Galicia, at both council and parish levels. Resultsreveal the connections between our variables, which reflectthe changes the regional forestry sector has experienced inthe past, and explain its current situation. They also confirmthe heterogeneity of forestry in the area and the need to adaptforest-planning strategies to each study unit, as well as tothe entire region.  相似文献   

Origin and metamorphic redistribution of silicon, chromium, and phosphorus in the metal of chondrites     

Zanda B  Bourot-Denise M  Perron C  Hewins RH 《Science (New York, N.Y.)》1994,265(5180):1846-1849

Chromium, silicon, and phosphorus concentrations of 0.1 to 1 percent by weight are common in metal grains in the least metamorphosed ordinary and carbonaceous chondrites. These concentrations are fairly uniform within single chondrules (but different from chondrule to chondrule) and are inversely correlated with the fayalite concentrations of the chondrule olivines. This relation shows that these chromium, silicon, and phosphorus concentrations could not have been established by condensation or equilibration in the solar nebula but are the result of metal-silicate equilibration within chondrules. Two generations of inclusions made by the exsolution of those elements have been identified: One formed during chondrule cooling and the other formed during metamorphism. The distribution and composition of the latter in type 3 to type 5 chondrites are consistent with increasing metamorphism relative to type 2 and type 3.0 material.  相似文献   

A cross-sectional pilot study to estimate the prevalence of and risk factors for leptospirosis in South-Western Victorian dairy herds, 2017     

E Erregger  MA Stevenson  DS Beggs  S Oswin  SP Jagoe  PD Mansell  MF Pyman 《Australian veterinary journal》2020,98(9):417-423

Leptospirosis is a zoonosis, found worldwide, affecting many species of animals. We conducted a cross-sectional study to estimate the prevalence of Leptospira borgpetersenii sv Hardjo and Leptospira interrogans sv Pomona in cattle in dairy herds in South-Western Victoria, Australia. Fifty-three herds were enrolled in the study. Urine samples were collected from 15 late-lactation cows in each herd. A questionnaire was provided to herd managers at the time of each herd visit, asking them to describe the methods they used for controlling leptospirosis, including vaccination. Urine samples were pooled at the herd level and tested for leptospira spp. using real time PCR. Urine samples from individual cows within the positive pooled samples were then tested for Leptospira Hardjo and Leptospira Pomona using qPCR. Four of the 53 herds showed positive leptospirosis results giving an apparent prevalence of 8 (95% CI 2–18) leptospira-positive herds per 100 herds at risk. Based on the 53 completed questionnaires, leptospirosis vaccination programs were not compliant with label directions in 36 of the 52 vaccinated herds: 69 (95% CI 55–81) of 100 herd managers that routinely vaccinated for leptospirosis did not comply with label directions. One herd was completely unvaccinated. Based on our findings, we estimate that approximately 10% of dairy farms in South-Western Victoria are likely to be infected with leptospirosis. While most herds are vaccinating for leptospirosis, most are not doing so according to label directions. We conclude that herd managers need to be better educated regarding leptospirosis vaccination programs.  相似文献   

Bovine ephemeral fever     

MF UREN 《Australian veterinary journal》1989,66(8):233-236

Ephemeral fever remains a viral disease of considerable importance to many countries including Australia. The virus has been only partly characterised and still awaits final classification. Although BEF virus was first thought to contain 6 structural proteins there is increasing evidence to suggest that it contains the 5 proteins characteristic of the Rhabdoviridae. Although BEF is thought to be arthropod borne, the vector has yet to be identified but it is clear from the distribution of BEF that more than one vector is capable of transmitting the disease. Despite rigorous investigation of the clinical signs and the pathology of ephemeral fever, little progress has been made on the pathogenesis of the disease. This has been partly due to the difficulty of propagating BEF virus in vitro and the inability to define the site of replication. However, there is mounting evidence to suggest that BEF is immunopathologic in nature and that the clinical expression of the disease is influenced by the release of one or more mediators of inflammation. The disease is characterised by a number of haematological and biochemical changes and early and prolonged treatment with phenylbutazone is capable of reversing a number of these changes. The intravenous administration of calcium can now be considered a justifiable addition to the treatment regimen together with prolonged phenylbutazone therapy. The vaccines currently available are prepared from either live attenuated or killed virus and may be less than reliable. There appears to be a need for a reliable, inexpensive, cold-chain independent alternative vaccine.  相似文献   

Effects of a highly concentrated hypertonic saline-dextran volume expander on cardiopulmonary function in anesthetized normovolemic horses.     

P F Moon  J R Snyder  S C Haskins  P R Perron  G C Kramer 《American journal of veterinary research》1991,52(10):1611-1618

Conventional fluid resuscitation is unsatisfactory in a small percentage of equine emergency surgical cases because the large volumes of fluids required cannot be given rapidly enough to adequately stabilize the horse. In anesthetized horses, the volume expansion and cardiopulmonary effects of a small volume of highly concentrated hypertonic saline-dextran solution were evaluated as an alternative initial fluid choice. Seven halothane-anesthetized, laterally recumbent, spontaneously ventilating, normovolemic horses were treated with a 25% NaCl-24% dextran 70 solution (HSD) at a dosage of 1.0 ml/kg of body weight, IV, infused over 10 minutes, and the effects were measured for 120 minutes after infusion. Plasma volume expansion was rapid and significant (from 36.6 +/- 4.6 ml/kg to 44.9 +/- 4.8 ml/kg), and remained significantly expanded for the duration of the experiment. Packed cell volume, total blood hemoglobin, and plasma protein concentrations significantly decreased, confirming rapid and sustained volume expansion with hemodilution. Cardiac index and stroke index immediately increased and remained high for the entire study (from 69.6 +/- 15.3 ml/min/kg to 106.6 +/- 28.4 ml/min/kg, and from 1.88 +/- 0.49 ml/beat/kg to 2.50 +/- 0.72 ml/beat/kg, respectively). Systemic vascular resistance significantly decreased immediately after HSD infusion and remained decreased for the duration of the study (from 1.41 +/- 0.45 mm of Hg/ml/min/kg to 0.88 +/- 0.22 mm of Hg/ml/min/kg). Arterial and venous blood oxygen content decreased significantly because of hemodilution, but actual oxygen transport transiently increased at the 10-minute measurement before returning toward baseline.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Chromatographie sur couche de gel de silice-charbon actif. Application a la separation analytique et preparative des acides gras satures et de leurs esters methyliques     

Mlle C. Madelmont  Mr. R. Perron 《Plant foods for human nutrition (Dordrecht, Netherlands)》1968,16(1-4):126-130

Résumé Les auteurs ont mis au point une méthode de chromatographie sur couche mince des substances selon leur caractère apolaire qui ne recourt pas aux techniques habituelles d'imprégnation. Le procédé, basé sur l'emploi de charbon actif mélangé en faibles proportions au gel de silice, a fourni d'excellents chromatogrammes d'acides gras saturés et de leurs esters méthyliques.La méthode utilisant une phase apolaire solide se prête facilement à la technique préparative. Des mélanges de laurate, myristate, palmitate et stéarate de méthyle, constituant des échantillons de 50 à 200 mg, ont été parfaitement résolus en leurs composants sur couches épaisses contenant des quantités variables de charbon actif.

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Summary The authors have evolved a method of thin-layer chromatography based on the non-polar characteristics of the substances, that does not resort to the usual impregnation techniques. The procedure, based on the use of activated carbon mixed in small proportions with silica gel, has given excellent chromatograms of saturated fatty acids and their methylesters.The method making use of a non-polar solid phase lends easily itself to the preparative technique. Mixtures of methyl laurate, myristate, palmitate, and stearate, making samples of 50 to 200 mg have been perfectly resolved in their components on thick layers containing variable amounts of activated carbon.

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Zusammenfassung Die Verfasser haben eine DC-Methode entwickelt für Stoffe gemäß deren apolaren Eigenschaften. Diese Methode benutzt nicht die gewöhnlichen Imprägnierungs-Techniken. Das Verfahren beruht auf der Anwendung von Aktivkohle, die in geringen Anteilen zum Siliziumgel gemischt ist. Wir erhielten sehr gute Chromatogramme von gesättigten Fettsäuren und deren Methylestern.Die Methode, die eine feste, apolare Phase benutzt, ist gut geeignet für die vorbereitende Technik. Gemische von Methyl-Laurat, Myristat, Palmitat und Stearat in Form von Proben von 50 bis 200mg, ergaben für ihre Bestandteile einwandfreie Ergebnisse auf Schichten mit verschiedenen Quantitäten von Aktivkohle.

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Un exposé plus complet de la technique est décrit dans: -Bull. Soc. Chim. France, 1967, 9,3443. - Bull. Soc. Chim. France, 1968, 6,2607.  相似文献   

The mystery of fungal infection in the guttural pouches     

Lepage OM  Perron MF  Cadoré JL 《Veterinary journal (London, England : 1997)》2004,168(1):60-64

Advances in the understanding of guttural pouch physiology and novel therapeutic approaches to mycotic infections in the horse are reviewed. It is suggested that the guttural pouches may contribute to the regulation of arterial blood temperature, cooling the circulation to the brain to below body temperature. Aspergillus spp. is the major organism found in a guttural pouch affected with mycosis but it is unclear why this agent becomes aggressive. Conventional therapy aims to prevent fatal haemorrhage and to treat any neurological lesions but it is desirable to try to prevent the disease. A technique consisting of inserting a transarterial coil into the internal carotid, external carotid and maxillary arteries in normal and affected horses has been reported to be rapid, safe and effective in occluding the arteries and in inducing regression of the mycotic lesions without adjunctive medical treatment. When faced with acute and uncontrollable epistaxis in the field, the most effective means to reduce haemorrhage is probably the occlusion of both common carotid arteries. However, how such arterial occlusions can result in the successful management of guttural pouch mycosis without antifungal medication remains a mystery.  相似文献   

A case of interstitial pneumonia associated with Pneumocystis carinii in a foal     

Perron Lepage MF  Gerber V  Suter MM 《Veterinary pathology》1999,36(6):621-624

Subacute interstitial pneumonia with diffuse alveolar damage, marked macrophage infiltration, and intracellular Pneumocystis carinii cysts is described in a 3-month-old Swiss warmblood foal. Clinically, the disease was characterized by sudden onset of respiratory distress with fatal outcome. Based on serum immunoglobulin G (IgG), IgA, and IgM values, no humoral immunosuppression was detected. Spleen, thymus, and bronchial lymph nodes did not reveal lymphoid depletion, as assessed by immunohistochemical staining of CD-3-positive cells. Immunopathogenesis of pulmonary infections with intracellular agents in foals is discussed.  相似文献   

A survey of northern Victorian dairy farmers to investigate dairy calf management: calf‐rearing practices          下载免费PDF全文

AJ Phipps  DS Beggs  AJ Murray  PD Mansell  MF Pyman 《Australian veterinary journal》2018,96(4):107-110

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