Electromyographic activity of the hyoepiglotticus muscle and control of epiglottis position in horses     

Holcombe SJ  Cornelisse CJ  Berney C  Robinson NE 《American journal of veterinary research》2002,63(12):1617-1621

OBJECTIVE: To determine whether the hyoepiglotticus muscle has respiratory-related electromyographic activity and whether electrical stimulation of this muscle changes the position and conformation of the epiglottis, thereby altering dimensions of the aditus laryngis. ANIMAL: 6 Standardbred horses. PROCEDURE: Horses were anesthetized, and a bipolar fine-wire electrode was placed in the hyoepiglotticus muscle of each horse. Endoscopic images of the nasopharynx and larynx were recorded during electrical stimulation of the hyoepiglotticus muscle in standing, unsedated horses. Dorsoventral length and area of the aditus laryngis were measured on images obtained before and during electrical stimulation. Electromyographic activity of the hyoepiglotticus muscle and nasopharyngeal pressures were measured while horses exercised on a treadmill at 50, 75, 90, and 100% of the speed that produced maximum heart rate. RESULTS: Electrical stimulation of the hyoepiglotticus muscle changed the shape of the epiglottis, displaced it ventrally, and significantly increased the dorsoventral length and area of the aditus laryngis. The hyoepiglotticus muscle had inspiratory activity that increased significantly with treadmill speed as a result of an increase in phasic and tonic activity. Expiratory activity of the hyoepiglotticus muscle did not change with treadmill speed in 4 of 6 horses. CONCLUSIONS AND CLINICAL RELEVANCE: Findings reported here suggest that contraction of the hyoepiglotticus muscle increases dimensions of the airway in horses by depressing the epiglottis ventrally during intense breathing efforts. The hyoepiglotticus muscle may be an important muscle for dilating the airway in horses, and contraction of the hyoepiglotticus muscle may induce conformational changes in the epiglottis.  相似文献   

Safety and efficacy of a technique for thoracoscopically guided pulmonary wedge resection in horses     

Lugo J  Stick JA  Peroni J  Harkema JR  Derksen FJ  Robinson NE 《American journal of veterinary research》2002,63(9):1232-1240

OBJECTIVE: To evaluate the safety and efficacy of thoracoscopically guided pulmonary wedge resection in horses. ANIMALS: 10 horses (5 control horses and 5 horses affected with recurrent airway obstruction [ie, heaves]). PROCEDURE: Each horse underwent a thoracoscopically guided pulmonary wedge resection. Before, during, and after surgery, heart rate, respiratory rate, arterial blood gases, and systemic and pulmonary arterial pressures were measured. Physical examination, CBC, and thoracic radiography and ultrasonography were performed 24 hours before and 2 and 48 hours after surgery. Pulmonary specimens were assessed by histologic examination. A second thoracoscopic procedure 14 days later was used to evaluate the resection site. RESULTS: The technique provided excellent specimens for histologic evaluation of the lung. Heart and respiratory rates decreased significantly after horses were administered sedatives. A significant transient decrease in Pao2 was detected immediately after pulmonary wedge resection, but we did not detect significant effects on arterial pH, Paco2, or mean arterial and pulmonary arterial pressures. All horses except 1 were clinically normal after thoracoscopic surgery; that horse developed hemothorax attributable to iatrogenic injury to the diaphragm. The second thoracoscopy revealed minimal inflammation, and there were no adhesions. CONCLUSIONS AND CLINICAL RELEVANCE: Thoracoscopically guided pulmonary wedge resection provides a minimally invasive method for use in obtaining specimens of lung tissues from healthy horses and those with lung disease. This technique may be useful for the diagnosis of diseases of the lungs and thoracic cavity.  相似文献   

Cerebrospinal fluid glutamine,tryptophan, and tryptophan metabolite concentrations in dogs with portosystemic shunts     

Holt DE  Washabau RJ  Djali S  Dayrell-Hart B  Drobatz KJ  Heyes MP  Robinson MB 《American journal of veterinary research》2002,63(8):1167-1171

OBJECTIVE: To determine whether glutamine (GLN), tryptophan (TRP), and tryptophan metabolite concentrations are higher in cerebralspinal fluid (CSF) dogs with naturally occurring portosystemic shunts (PSS), compared with control dogs. ANIMALS: 11 dogs with confirmed PSS and 12 control dogs fed low- and high-protein diets. PROCEDURE: Cerebrospinal fluid and blood samples were collected from all dogs. Serum and CSF concentrations of GLN, alanine, serine, TRP, 5-hydroxyindoleacetic acid (5-HIAA), and quinolinic acid (QUIN) were measured. RESULTS: Cerebrospinal fluid concentrations of GLN, TRP, and 5-HIAA were significantly higher in PSS dogs, compared with control dogs fed high- or low-protein diets. Cerebrospinal fluid QUIN concentration was significantly higher in PSS dogs, compared with control dogs fed the low-protein diet. Serum QUIN concentration was significantly lower in PSS dogs, compared with control dogs fed either high- or low-protein diets. CONCLUSIONS AND CLINICAL RELEVANCE: An increase in CNS GLN concentration is associated with high CSF concentrations of TRP and TRP metabolites in dogs with PSS. High CSF 5-HIAA concentrations indicate an increased flux of TRP through the CNS serotonin metabolic pathway, whereas high CSF QUIN concentrations indicate an increased metabolism of TRP through the indolamine-2,3-dioxygenase pathway. The high CSF QUIN concentrations in the face of low serum QUIN concentrations in dogs with PSS indicates that QUIN production from TRP is occurring in the CNS. High concentrations of QUIN and other TRP metabolites in the CNS may contribute to neurologic abnormalities found in dogs with PSS and hepatic encephalopathy.  相似文献   

Competition Commission inquiry into Poms     

Robinson A 《The Veterinary record》2002,151(19):582-583

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Prednisone per os is likely to have limited efficacy in horses     

Peroni DL  Stanley S  Kollias-Baker C  Robinson NE 《Equine veterinary journal》2002,34(3):283-287

Based on its efficacy for the treatment of human asthma, the corticosteroid prednisone is commonly used in horses for treatment of recurrent airway obstruction. However, recent studies have failed to show any benefit of prednisone tablets for the treatment of this condition. The purpose of this study was to determine why oral prednisone has poor efficacy for the treatment of heaves in horses. In a crossover study, 5 horses were given the following treatments: prednisone tablets, prednisone liquid, prednisolone tablets, prednisolone liquid and i.v. prednisolone sodium succinate (positive control). Blood samples were taken before drug administration and at selected time points during a 24 h period. Serum concentrations of prednisone and prednisolone were determined in order to evaluate gastrointestinal absorption and hepatic metabolism. Serum concentrations of the endogenous glucocorticoid hydrocortisone were also determined as an indicator of the biological activity of the drugs. Both prednisolone tablets and liquid were absorbed rapidly, with prednisolone detectable in serum within 15 min of administration and with peak concentrations occurring within 45 min. Small amounts of prednisone were detected in the serum samples after administration of both prednisone tablets and liquid. Prednisolone was not detected in serum samples after administration of prednisone liquid and was detected in serum samples from only one horse after administration of prednisone tablets. Endogenous hydrocortisone production was suppressed when horses received prednisolone. The results of these studies indicate that prednisone has poor efficacy for the treatment of heaves because it is poorly absorbed and the active metabolite prednisolone is rarely produced. In contrast, prednisolone tablets have excellent bioavailability and should be useful as a therapeutic agent in horses.  相似文献   

In utero programming of sexually differentiated gonadotrophin releasing hormone (GnRH) secretion     

Robinson JE  Birch RA  Taylor JA  Foster DL  Padmanabhan V 《Domestic animal endocrinology》2002,23(1-2):43-52

It has long been recognised that steroids can have both organisational and activational effects on the reproductive neuroendocrine axis of many species, including the sheep. Specifically, if the ovine foetus is exposed to testosterone during a relatively short 'window' of in utero development (from approximately day 30-90 of a 147 day pregnancy) the neural mechanisms regulating gonadotrophin releasing hormone (GnRH) secretion become organised in a male-specific manner. In post-natal life the consequences of foetal androgen exposure are sexually differentiated responses of the GnRH neuronal network to activation by factors such as photoperiod and ovarian steroid hormones. Studies in the gonadectomized lamb have demonstrated that elevated concentrations of oestrogen (E) are unable to trigger a preovulatory-like GnRH surge in the male and the androgenized ewe lamb. Further, these animals have markedly reduced sensitivity to the inhibitory actions of progesterone on tonic GnRH release compared with normal ewes. The reasons for these abnormal steroid feedback mechanisms may reside in sexually dimorphic inputs to the GnRH neurone, including those from oestrogen-receptive neurones in the arcuate nucleus that synthetize the neuropeptide, neurokinin B (NKB). The consequences of in utero androgen exposure are reflected in a progressive and dramatic impairment of fertility in the ovary-intact ewe.  相似文献   

Efficacy of three corticosteroids for the treatment of heaves     

Robinson NE  Jackson C  Jefcoat A  Berney C  Peroni D  Derksen FJ 《Equine veterinary journal》2002,34(1):17-22

This study used a cross-over design to compare the efficacy of 3 corticosteroids for the relief of airway obstruction and inflammation in 9 heaves-affected horses. The severity of airway obstruction and inflammation was quantified by measurement of lung function and by bronchoalveolar lavage fluid (BALF) cytology, respectively. Airway obstruction was induced by stabling the horses and they remained stabled during the 10 day treatment period. Lung function was measured before treatment (baseline), at Days 3, 7, and 10 of treatment, and after 30 days at pasture. BALF cytology was investigated at baseline, Day 10, and at pasture. All 9 horses received the following 4 treatments in random order: no treatment, daily oral prednisone tablets (1 mg/kg), daily i.v. dexamethasone solution (0.1 mg/kg), and i.m. dexamethasone-21-isonicotinate (0.04 mg/kg) every 3 days. When horses received no treatment, lung function did not change significantly during stabling but improved at pasture. In all horses, daily i.v. administration of dexamethasone solution improved lung function within 3 days to levels as good as or better than those measured at pasture. Dexamethasone-21-isonicotinate was rapidly effective in 8 of 9 horses. The other horse did not respond to this drug. Prednisone tablets were without effect on Days 3 and 7 of treatment, but by Day 10, 5 of 9 horses showed some improvement in lung function. Dexamethasone i.v. solution decreased the percent neutrophils in BALF at Day 10. Other treatments had no effect on BALF cytology. These results demonstrate that dexamethasone rapidly relieved airway obstruction in heaves-affected horses. Oral prednisone had inconsistent effects but may be beneficial in some horses after more than a week of treatment.  相似文献   

Evaluation of the analgesic effects of epidurally administered morphine, alfentanil, butorphanol, tramadol, and U50488H in horses   总被引：4，自引：0，他引：4  

Natalini CC  Robinson EP 《American journal of veterinary research》2000,61(12):1579-1586

OBJECTIVE: To evaluate and compare effects of epidurally administered morphine, alfentanil, butorphanol, tramadol, and U50488H on avoidance threshold to noxious electrical stimulation over the dermatomes of the perineal, sacral, lumbar, and thoracic regions in horses. ANIMALS: 5 healthy adult horses. PROCEDURE: Using a Latin square complete repeated-measures design, horses were randomly assigned to receive 1 of 6 treatments (morphine, alfentanil, butorphanol, tramadol, U50488H, or sterile water) at intervals of at least 7 days. Agents were injected epidurally at the first intercoccygeal epidural space, and electrical stimulation was applied at repeated intervals for 24 hours to the dermatomes of the perineal, sacral, lumbar, and thoracic regions. Avoidance threshold to electrical stimulation was recorded. RESULTS: Administration of butorphanol, U50488H, and sterile water did not induce change in avoidance threshold. Alfentanil increased avoidance threshold during the first 4 hours, but not significantly. Tramadol and morphine significantly increased threshold and analgesic effects. Complete analgesia (avoidance threshold, >40 V) in the perineal and sacral areas was achieved 30 minutes after tramadol injection, compared with 6 hours after morphine injection. Duration of complete analgesia was 4 hours and 5 hours after tramadol and morphine injections, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Epidural administration of tramadol and morphine induces long-lasting analgesia in healthy adult horses. Epidural administration of opioids may provide long-lasting analgesia in horses without excitation of the CNS.  相似文献   

Velogenic Newcastle disease in imported caged birds          下载免费PDF全文

Clavijo A  Robinson Y  Booth T  Munroe F 《The Canadian veterinary journal. La revue veterinaire canadienne》2000,41(5):404-406

Velogenic Newcastle disease was diagnosed in pet birds intended for importation into Canada. Virological and histopathological examination confirmed the presence of the disease. The group of birds was denied entry into Canada. Similar birds illegally imported are a potential source of velogenic Newcastle disease virus and are a threat to domestic poultry.  相似文献   

Nitrogen metabolism and fertility in cattle: I. Adaptive changes in intake and metabolism to diets differing in their rate of energy and nitrogen release in the rumen     

Sinclair KD  Sinclair LA  Robinson JJ 《Journal of animal science》2000,78(10):2659-2669

The ruminal degradability, intake, and metabolism of diets differing in their relative rate of energy and nitrogen release in the rumen were characterized prior to their use in a study of the effects of high peripheral levels of ammonia on reproductive function in cattle. In a 2 x 2 factorial experiment, replicated four times, 16 heifers were offered isocaloric and isonitrogenous diets containing two sources of fermentable carbohydrate, fiber (slow energy release, SE) or starch (fast energy release, FE), and two rates of nitrogen release, which were either synchronous (S) or asynchronous (A) to that of energy release. Throughout the experiment, the amount of feed offered was held constant, at a level equivalent to 1.5 x maintenance. Four ruminally fistulated sheep were used to determine the in situ degradability of these diets. The 16 heifers were bled before feeding at 0800 and at 0900, 1000, 1100, 1200, 1400, and 1600 on d 0 (introduction to dietary treatments) and on d 4, 7, 11, 14, 21, and 28. Diet refusals were recorded at hourly intervals after feeding. The rapidly degradable nitrogen fraction of the SE:A and FE:A diets was greater than that of the SE:S and FE:S diets. Postprandial jugular plasma ammonia levels rose to a peak of around 300 micromol/L in heifers offered the SE:A and FE:A diets but did not rise in heifers offered the SE:S and FE:S diets. All feed offered was consumed within 1 h on diets SE:S and FE:S throughout the experiment. The proportion of feed consumed within 1 h of feeding declined from 100% on d 0 to around 70 and 56% by d 21 for heifers given the SE:A and FE:A diets, respectively. Peak postprandial plasma ammonia levels were accordingly lower, at around 160 micromol/L. Plasma urea levels averaged 7 mmol/L and were unaffected by dietary treatment. High plasma ammonia levels were associated with a suppression in the normal postprandial rise in insulin. There was no significant metabolic adaptation to high-ammonia-generating diets, and heifers given these diets modified their pattern of intake in an apparent attempt to avoid excessively high levels of plasma ammonia.  相似文献