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Normal Horses (normal + horse)
Selected AbstractsSedation with detomidine and acepromazine influences the endoscopic evaluation of laryngeal function in horsesEQUINE VETERINARY JOURNAL, Issue 6 2007C. Lindegaard Summary Reasons for performing study: Endoscopy of the upper airways of horses is used as a diagnostic tool and at purchase examinations. On some occasions it is necessary to use sedation during the procedure and it is often speculated that the result of the examination might be influenced due to the muscle-relaxing properties of the most commonly used sedatives. Objectives: To evaluate the effect of detomidine (0.01 mg/kg bwt) and acepromazine (0.05 mg/kg bwt) on the appearance of symmetry of rima glottidis, ability to abduct maximally the arytenoid cartilages and the effect on recurrent laryngeal neuropathy (RLN) grade. Methods: Forty-two apparently normal horses underwent endoscopic examination of the upper airways on 3 different occasions, under the influence of 3 different treatments: no sedation (control), sedation with detomidine and sedation with acepromazine. All examinations were performed with a minimum of one week apart. The study was performed as an observer-blind cross-over study. Results: Sedation with detomidine had a significant effect on the RLN grading (OR = 2.91) and ability maximally to abduct the left arytenoid cartilages (OR = 2.91). Sedation with acepromazine resulted in OR = 2.43 for the RLN grading and OR = 2.22 for the ability to abduct maximally. The ability to abduct maximally the right arytenoid cartilage was not altered. Conclusions: Sedating apparently healthy horses with detomidine or acepromazine significantly impairs these horses' ability to abduct fully the left but not the right arytenoid cartilage. This resulted in different diagnosis with respect to RLN when comparing sedation to no sedation. Potential relevance: Since the ability to abduct the right arytenoid cartilage fully is not altered by sedation, it is speculated that horses changing from normal to abnormal laryngeal function when sedated, might be horses in an early stage of the disease. To confirm or reject these speculations, further studies are needed. Until then sedation during endoscopy should be used with care. [source] Laminar xanthine oxidase, superoxide dismutase and catalase activities in the prodromal stage of black-walnut induced equine laminitisEQUINE VETERINARY JOURNAL, Issue 1 2007J. P. LOFTUS Summary Reasons for study: Xanthine oxidase (XO)-dependent production of superoxide anion and hydrogen peroxide, a characteristic of ischaemia-reperfusion injury, may contribute to the development of equine laminitis. Objective: To determine the levels of XO and antioxidant enzymes (catalase, superoxide dismutase [SOD]) in the digital laminae of normal horses (CON) and horses in the developmental stage of laminitis using the black walnut extract (BWE) model. Methods: Healthy horses (n = 12) were administered BWE (BWE group, n = 6), or water (CON group, n = 6) through a nasogastric tube. At the onset of leucopenia in the BWE-treated animals, all horses were anaesthetised, digital laminae and other samples collected rapidly and flash frozen, and the animals subjected to euthanasia. Extracts of the frozen tissues were assayed for the 2 conformational forms of xanthine: oxygen oxidoreductase (XOR), namely, xanthine dehydrogenase (XDH) and xanthine oxidase (XO), as well as the antioxidant enzymes, SOD and catalase. Results: Extracts of liver, lungs and skin, but not digital laminae, from either CON or BWE-treated horses had endogenous SOD, whereas all had endogenous XO and catalase. The levels of XDH, XO and catalase were similar in extracts of laminae from CON and BWE-treated horses as was the ratio of XDH to XO in extracts. Conclusions and potential relevance: The absence of increased XO activity suggest against the involvement of this reactive oxygen intermediate-generating system in the development of laminar pathology in BWE-treated horses. Conversely, the absence of SOD from extracts of equine digital laminae, but not other tissues, suggests that the equine digital laminae are highly susceptible to damage by superoxide anion, produced, for example, by emigrant inflammatory leucocytes. [source] The effect of bilateral glossopharyngeal nerve anaesthesia on swallowing in horsesEQUINE VETERINARY JOURNAL, Issue 1 2005E. A. KLEBE Summary Reasons for performing study: Dysfunction of the glossopharyngeal nerve has been implicated as a cause of dysphagia in horses. However, recent studies have indicated that this is not the case. Objectives: To determine whether bilateral glossopharyngeal nerve anaesthesia would cause dysphagia in horses or result in measurable alterations in the timing, function, or sequence of swallowing. Methods: Swallowing was evaluated in 6 normal horses with and without bilateral glossopharyngeal nerve anaesthesia. Swallowing dynamics were assessed subjectively and objectively based on time from prehension of food until swallowing, number of tongue movements until initiation of swallowing, depth of bolus at the base of the tongue prior to initiation of swallow and evidence of tracheal aspiration using fluoroscopy and endoscopy. Results: There was no evidence of aspiration or dysphagia in horses before or after bilateral glossopharyngeal nerve block. No observed or measured differences in swallowing sequence or function could be detected in blocked compared to unblocked horses. However, there was a trend in blocked horses for the number of tongue pushes and the time to swallowing to be increased. Conclusions: Glossopharyngeal nerve function may not be essential for normal swallowing function in otherwise healthy horses. Potential relevance: Clinically, normal swallowing is not an appropriate test of glossopharyngeal nerve function and dysphagic horses should not be assumed to have glossopharyngeal nerve dysfunction. [source] Validation and clinical utility of a novel immunoradiometric assay exclusively for biologically active whole parathyroid hormone in the horseEQUINE VETERINARY JOURNAL, Issue 3 2003J. C. ESTEPA Summary Reasons for performing study: Parathyroid hormone (PTH) plays a critical role in the regulation of mineral metabolism in mammals. Until recently, the standard method for PTH measurement has been the 2nd generation intact-PTH (I-PTH) assay. Current evidence indicates that the I-PTH assay binds to the PTH molecule and to an inactive N-terminally truncated PTH fragment that tends to accumulate in the blood of uraemic patients. Therefore, a new 3rd generation PTH assay that detects only the whole PTH molecule (W-PTH; cyclase-activating PTH [CAP]) has been developed. Objectives: To validate this more specific W-PTH assay for measurement of equine PTH and evaluate its clinical utility. Methods: W-PTH and I-PTH were measured in plasma samples from normal horses (adults and foals) and horses with nutritional secondary hyperparathyroidism (N2HPT) and with chronic renal failure (CRF). Replicate measurements and dilutional paralellism were used for assay validation. Changes in blood ionized calcium were induced by EDTA and CaCl2 administration. Results: Performance of the W-PTH assay (accuracy, sensitivity, specificity and ability to detect changes in PTH in response to changes in calcium) was similar to that of the I-PTH assay. Surprisingly, the relative W-PTH concentration in normal horses and foals was higher than the relative I-PTH concentration. W-PTH values remained higher than I-PTH during acute hypo- and hypercalcaemia. An increase in both W-PTH and I-PTH concentrations was found in horses with N2HPT. In horses with CRF, W-PTH and I-PTH values were very low and no increase in I-PTH was observed. Conclusions: The W-PTH assay can be used for measurement of equine PTH. Potential relevance: The use of W-PTH assay is likely to improve the diagnosis of mineral metabolism in horses. [source] Wedge-shaped conformation of the dorsolateral aspect of the third tarsal bone in the Thoroughbred racehorse is associated with development of slab fractures in this siteEQUINE VETERINARY JOURNAL, Issue 6 2001D. H. BAIRD Summary Anecdotal evidence suggested that many cases of third tarsal bone (T3) fracture encountered clinically were associated with an abnormal shape to this bone. The radiographs of 10 normal horses and 10 horses affected with slab fracture of T3 were therefore examined to ascertain if any pre-existent radiological abnormality was present in cases of fracture. Measurement of the maximum and minimum width between the proximal and distal articular surfaces of the dorsolateral aspect of this bone was carried out on a standardised dorso-50° medial-palmarolateral radiographic projection of the tarsus of each horse. To avoid artefacts produced by possible image magnification, ratios of these values were used for comparison between horses. The results showed that wedge shaped conformation of T3, in which the articular surfaces of the bone converge and then diverge again on the dorsolateral aspect, was over-represented in the population of horses sustaining T3 fracture when compared to controls. This information may be important in making judgements on the suitability of horses during prepurchase examination for racing. [source] Muscle thickness and neuron density in the caecum of horses with chronic recurrent caecal impactionEQUINE VETERINARY JOURNAL, Issue S32 2000G. F. SCHUSSER Summary In this study, the hypothesis that caecal smooth muscle layers would be thinner and the linear neuron density of myenteric plexus greater was tested in normal horses compared to those with chronic recurrent caecal impaction. Four normal horses and 18 horses with chronic recurrent caecal impaction were subjected to euthanasia and 7 tissue samples were collected from each horse at different regions of the caecum (apex, dorsal body, cranial base, dorsal base, caudal base, caudal body, ventral body). Twelve horses with chronic recurrent caecal impaction were treated surgically. Only one tissue sample of the cranial part of the caecal base close to the caecocolic orifice was taken during surgery. The thickness of the circular muscle layer of all caecal regions measured in killed horses with chronic recurrent caecal impaction was significantly increased compared to the equivalent caecal region of normal horses. On the other hand, the longitudinal muscle layer was significantly thicker only in the cranial and caudal caecal base and in the dorsal region of the caecal body. The linear neuron densities of all caecal base areas and 2 caecal body regions, the caudal body region and of the apex, of killed horses with chronic recurrent caecal impaction were significantly lower compared with those in clinically normal horses. The circular muscle layer of all caecal regions was thickened (hypertrophied) probably as a consequence of chronic uncoordinated hypercontractility due to neuron deficit in the myenteric plexus of the caecal base. [source] Measurement of Free Thyroxine Concentration in Horses by Equilibrium DialysisJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 2 2006Babetta A. Breuhaus The purpose of the study reported here was to validate measurement of free thyroxine (fT4) concentration in equine serum by equilibrium dialysis (fT4D), and to compare values with fT4 concentration measured directly and with total T4 (TT4) concentration. The fT4D, fT74, and TT4 concentrations were measured over a range of values in euthyroid horses and horses made hypothyroid by administration of propylthiouracil (PTU). Concentrations of fT4D (<1.8,83 pmol/L) were consistently higher than those of fT4 (<1,40 pmol/L). There was a significant (P < .001) regression of fT4D on fT4 in 503 samples from normal horses (y = 2.086x - 0.430). In baseline samples from 71 healthy euthyroid horses, fT4 concentration ranged from 6- 21 pmol/L (median, 11 pmol/L; 95% confidence interval [CI]10.5,11.8 pmol/L), and fT4D concentration ranged from 7,47 pmol/L (median, 22 pmol/L; 95% CI 20.9,25.1 pmol/L). Free T4D, fT4, and TT4 concentrations were also measured in 34 ill horses. Horses consuming PTU and ill horses had significantly (P < .05) lower serum concentration of TT4, fT4, and fT4D than did clinically normal, healthy horses. If serum samples from ill horses were further subdivided into samples from horses that lived and samples from horses that died, fT4D concentration was not significantly different in ill horses that lived, compared with that in healthy horses, whereas fT4 concentration was still significantly decreased in ill horses that died (P < 0.001). We conclude that measurement of fT4 concentration by equilibrium dialysis is a valid technique in the horse, and its use may provide improved ability to distinguish nonthyroidal illness syndrome from hypothyroidism in that species. [source] Pharmacokinetics of amoxycillin in normal horses and horses with experimental arthritisJOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 1 2001J. O. Errecalde The serum and synovial pharmacokinetics of amoxycillin (AMX) were studied after i.v. administration at a dosage of 40 mg/kg to normal horses and horses with induced aseptic carpal arthritis. The best estimates of serum and synovial pharmacokinetic parameters were calculated by mono or bivariable non-linear regression analysis. A biexponential equation was used to describe the concentration vs. time profiles in both normal and arthritic horses. There were no serum kinetic differences between normal and arthritic horses. There were, however, major synovial kinetic changes between these groups. The rate of penetration from serum to synovial fluid was larger in arthritic animals, indicating better penetration in this case. On the other hand, the rate of disappearance from synovial fluid was larger in normal horses, indicating more persistence of the drug in the diseased joint. Synovial AMX availability increased from 21% in normal horses to 79% in arthritic horses. These findings support the use of AMX for the treatment of infectious synovial joint disease produced by susceptible organisms in horses. [source] | ||||||||||