Central and local actions of opioids upon reticulo-ruminal motility in sheep     

C. L. Maas  B. F. Leek 《Veterinary research communications》1985,9(1):89-113

The effects of opioids and naloxone on cyclical forestomach motility were determined in anaesthetized and conscious sheep. To assess central or peripheral opioid actions, differential routes of administration were used. Possible dynamic effects along the innervating vagovagal reflex arc were investigated electrophysiologically at the cervical level of the vagus nerve. Further, direct influences on the smooth muscle were evaluatedin vitro on isolated longitudinal reticular strips. Additionally, the effects of some spasmogenic agents were studied for comparative purposes. In anaesthetized sheep, opioids depressed in an identical manner both the amplitude of spontaneous cyclical contractions and contractions evoked by electrical stimulation of the distal end of the cut cervical vagus. In conscious sheep, low doses of normorphine and loperamide inhibited frequency and amplitude centrally (20 g/kg and 4 g/kg via carotid artery respectively), whereas locally higher dose levels (200 g/kg and 10 g/kg via coeliac artery respectively) affected only the amplitude of cyclical contractions. Furthermore the opioid peptides Leu-, Met-enkephalin and [D-Ala²-Met⁵]-enkephalinamide preferentially depressed the amplitude of cyclical motility most efficiently if administrated via the coeliac artery. These results indicate the presence both of a central opioid action depressing frequency and amplitude and of a local opioid action depressing only the amplitude of cyclical reticulo-ruminal motility. Opioids did not alter the resting discharge of afferent tension units and similarly failed to modulate tone of reticular stripsin vitro, suggesting that the opioids act locally on the intramural neuronal plexus, possibly by diminishing the output of excitatory transmitter. Whether substance P could play a role as a vagal excitatory transmitter besides the classically implicated acetylcholine has been discussed. The central opioid mechanism is probably not situated within the gastric centres but elsewhere in the brain. Naloxone ( 100 g/kg, jugular vein) stimulated the frequency of cyclical ruminal motility only in well-defined experimental conditions, probably via a central mechanism.  相似文献   

Tumours of Begonia and some other ornamentals,induced by Corynebacterium fascians     

H. A. Van Hoof  H. Huttinga  A. Knaap  H. P. Maas Geesteranus  W. H. M. Mosch  D. G. J. De Raay-Wieringa 《European journal of plant pathology / European Foundation for Plant Pathology》1979,85(3):87-98

In 1975 many tumours were observed in plants ofBegonia Schwabenland grown in Aalsmeer. Submersion of the roots ofNicotiana megalosiphon seedlings in a homogenate of tumorous tissue, induced tumours after two weeks. Short periods of submergence yielded results similar to those obtained after longer periods. Tumour homogenates lost their infectivity after ten min at 50°C. Aphids transmitted the infectious agent.Treatment with propylene oxide did not inhibit infectivity completely. Filtration through a 450 nm filter removed the infectious agent.Tobacco tumor virus or a viroid could not be isolated. Cultures ofCorynebacterium fascians, isolated from tumours ofN. megalosiphon were highly infectious and induced tumours in healthyN. megalosiphon andBegonia. Tumorous tissue homogenates ofPelargonium zonale, Dahlia sp.,Gladiolus sp., andLilium sp. also caused tumours inN. megalosiphon, from whichC. fascians was isolated. It was not possible to produce tumours inN. megalosiphon with homogenates from roses with symptoms of bud proliferation.Samenvatting In 1975 werden vele tumoren waargenomen inBegonia Schwabenland op Aalsmeerse bedrijven (Fig. 1). De infectiositeit van tumorweefsel kon goed en snel worden vastgesteld door de wortels van zaailingen vanNicotiana megalosiphon in een homogenaat van tumorweefsel te dompelen. Tumoren ontstonden na twee weken, de eindbeoordeling geschiedde na een maand (Fig. 2). Ook verschillende andereNicotiana spp.,Melilotus officinalis (Fig. 3) enPisum odoratum (Fig. 4) werden aangetast.Bij de infectiositeitstoets gaven zeer korte dompeltijden even goede resultaten als langere (Tabel 1). Infectieus sap verloor zijn infectievermogen na 10 min verhitting bij 50°C. Bladluizen brachten de smetstof over. Propyleenoxide verminderde de infectiositeit wel, doch onderdrukte deze niet totaal. Bij filtratie door een 450 nm filter bleef het infectieuse agens op het filter achter. Het tumor-inducerende agens was ook aanwezig in die delen van planten met tumoren welke gezond leken en het ging voor een gering deel over met zaad (Tabel 2).Uit tumoren konden wij geen tabakstumorvirus of een viroïde isoleren. Culturen vanCorynebacterium fascians, geïsoleerd uit tumoren vanN. megalosiphon bleken zeer infectieus en veroorzaakten tumoren inN. megalosiphon enBegonia. Homogenaten van tumorweefsel vanPelargonium zonale, dahlia (Fig. 5), gladiool (Fig. 6) enLilium Mid Century Hybrid Enchantment (Fig. 7) veroorzaakten ook tumoren opN. megalosiphon, waaruitC. fascians werd geïsoleerd. Met sap van kroeskopzieke rozen konden wijN. megalosiphon niet besmetten.  相似文献   

Erwinia carotovora (Jones) Bergey et al. var. atroseptica (Hellmers et Dowson) Dye. Seed Tuber Infection Versus Symptom Expression in the Field1     

H.P. Maas Geesteranus  H. Vruggink 《EPPO Bulletin》1976,6(4):223-224

Based on the time that symptoms of blackleg become evident in the field and the various ways of inoculation, it is concluded that the spread of symptom expression is due to the depth at which the bacteria penetrate into the interior of the tubers. Moreover, it is demonstrated that it is not the closed lenticels which prevent penetration, but the absence of a waterfilm in the intercellular spaces of the tuber tissue.  相似文献   

Effect of pre‐milking teat disinfection on clinical mastitis incidence in a dairy herd in Northern Queensland,Australia          下载免费PDF全文

SM Rowe  WP Tranter  RA Laven 《Australian veterinary journal》2018,96(3):69-75

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A comparison of the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts after calving in cows also given internal teat sealants     

LK Whitfield  RA Laven 《New Zealand veterinary journal》2018,66(1):44-47

AIM: To compare, in cows treated with an internal teat sealant, the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts (SCC) after calving.

METHODS: Cows from a spring-calving, pasture-based dairy farm in the Manawatu-Whanganui region of New Zealand were randomly allocated to receive either a short-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=291) or a long-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=288) at the end of lactation. Cows were managed on-farm with routine husbandry procedures through the dry period and following calving. A multivariable logistic regression model was used to determine the association between length of action of dry-cow therapy and the proportion of cows with a SCC >150,000?cells/mL at the first herd test after calving.

RESULTS: Age of cow, mean SCC for the preceding season and interval from calving to the first post-calving herd test were all associated with the proportion of cows with an individual SCC >150,000?cells/mL at the first herd test (p<0.001) Treatment with the short-acting dry-cow therapy was not associated with decreased odds of cows having a SCC >150,000?cells/mL at the first herd test compared with treatment with long-acting dry-cow therapy (OR=0.724; 95% CI=0.40–1.30).

CONCLUSIONS AND CLINICAL RELEVANCE: In this herd, which routinely used internal teat sealants, the use of short-acting cloxacillin-based dry-cow therapy did not result in an increased proportion of cows with elevated SSC post-calving. This was a single farm, single year study but indicates that in this herd, changing from a long-acting to a short-acting antimicrobial may have no impact on the prevalence of subclinical mastitis.  相似文献   

Book review
M. Luc, R.A. Sikora & J. Bridge (Eds), 1990. C.A.B. International, Oxon, UK. XVII+629pp.: text with tables and illustrations; references at the end of each chapter; 16 colour plates; 2 appendices; general index (15pp). ISBN 0-85198-630-7. Cloth bound. Price ￡ 60 (US$ 98.50, Americas only)     

P. W. Th. Maas 《European journal of plant pathology / European Foundation for Plant Pathology》1990,96(6):330

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Efficacy of ethylenediamine dihydriodide in the prevention of naturally occurring foot rot in cattle     

J Maas  L E Davis  C Hempstead  J N Berg  K A Hoffman 《American journal of veterinary research》1984,45(11):2347-2350

The efficacy of an ethylenediamine dihydriodide containing salt mixture was evaluated with regard to the prevention of naturally occurring foot rot in pastured cattle. Ninety-six cattle were assigned to the treatment group and 96 were assigned to the control group. The groups were allowed consumption of salt-mineral mixtures, ad libitum, that were identical, except with respect to iodine concentration. The control group's mixture contained 0.0025% iodine and the treatment group's mixture contained 0.125% iodine (0.156% ethylenediamine dihydriodide). The incidence of foot rot was measured, as was the severity of the lesions and accompanying lameness. The incidence of foot rot in the control group (20.8%) was significantly (P less than 0.05) greater than the incidence in the treatment group (8.3%). The severity of foot rot was greater (P = 0.024) in the control calves vs the treatment calves. Total serum iodine concentrations were measured in the 2 groups on days 0, 46, and 130 of the experiment. The serum iodine values of the treatment group on day 46 (46 +/- 19.8 g/dl) and day 130 (23 +/- 12.3 g/dl) were significantly different (P less than 0.01) than the serum iodine concentrations of the control animals and the pretreatment values (day 0) of both groups. Production was measured via calf weaning weights. There were no detectable differences between the 205-day adjusted weaning weights of the calves in the control group vs the calves in the treatment group. Clinical signs of iodism were not observed in the cattle involved in this study.  相似文献   

CARBON MONOXIDE EUTHANASIA IN DOGS     

H. W. de  Vries  A. N. E. Zimmermann  W. Storm van  Leeuwen  A. H. J. Maas  J. M. C. Douze 《Veterinary anaesthesia and analgesia》1974,5(1):25-26

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Genetic characterization of 2 novel feline caliciviruses isolated from cats with idiopathic lower urinary tract disease     

Rice CC  Kruger JM  Venta PJ  Vilnis A  Maas KA  Dulin JA  Maes RK 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2002,16(3):293-302

Feline caliciviruses (FCVs) are potential etiologic agents in feline idiopathic lower urinary tract disease (I-LUTD). By means of a modified virus isolation method, we examined urine obtained from 28 male and female cats with nonobstructive I-LUTD, 12 male cats with obstructive I-LUTD, and 18 clinically healthy male and female cats. All cats had been routinely vaccinated for FCV. Two FCVs were isolated; I (FCV-U1) from a female cat with nonobstructive I-LUTD, and another (FCV-U2) from a male cat with obstructive I-LUTD. To determine the genetic relationship of FCV-U1 and FCV-U2 to other FCVs. capsid protein gene RNA was reverse transcribed into cDNA, amplified, and sequenced. Multiple amino acid sequence alignments and phylogenetic trees were constructed for the entire capsid protein, hypervariable region E, and the more conserved (nonhypervariable) regions A, B, D, and F. When compared to 23 other FCV isolates with known biotypes, the overall amino acid sequence identity of the capsid protein of FCV-U1 and FCV-U2 ranged from 83 to 96%; identity of hypervariable regions C and E ranged from 58 to 85%. Phylogenetically, FCV-U1 clearly separated from other FCV strains in phenograms based on nonhypervariable regions. In contrast, FCV-U2 consistently segregated with the Urbana strain in all phenograms. Clustering of isolates by geographic origin was most apparent in phenograms based on nonhypervariable regions. No clustering of isolates by biotype was apparent in any phenograms. Our results indicate that FCV-UI and FCV-U2 are genetically distinct from other known vaccine and field strains of FCV.  相似文献   

Temporomandibular joint ankylosis in cats and dogs. A report of 10 cases.     

C P H J Maas  L F H Theyse 《Veterinary and comparative orthopaedics and traumatology》2007,20(3):192-197

Temporomandibular joint (TMJ) ankylosis is characterized by difficulty or inability to open the mouth. The ankylosis may be articular ('true') or extra-articular ('false'). Clinical signs, radiographic studies, treatment and follow-up are presented in a retrospective study involving five cats and five dogs. The findings were compared with TMJ ankylosis in humans. CT imaging with three-dimensional reconstruction proved to be of great value in determining the extent of the abnormalities and helped with preoperative planning. Articular TMJ ankylosis occurred in six animals and extra-articular TMJ ankylosis was found in the other four cases. In three cats and in three dogs, the TMJ ankylosis was trauma related; the remaining patients were diagnosed with a tumour. Resection of ankylosing tissue in false ankylosis or gap arthroplasty in true ankylosis was successful in all of the trauma induced cases. In the two cats, with tumour related ankylosis, the ankylosis was caused by an osteoma and resection had a good prognosis, whereas the two dogs had to be euthanatized.  相似文献