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Añor S Lipsitz D Williams DC Tripp L Willits N Maselli R LeCouteur RA 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2003,17(4):545-550
Single-fiber electromyography (SFEMG), a technique used to investigate neuromuscular transmission, has been described previously in the pelvic limb of dogs. Because preferential involvement of isolated muscle groups can occur in disorders of neuromuscular transmission, SFEMG was done in the peroneus longus (PL), extensor carpi radialis (ECR), and orbicularis oculi (OO) muscles of 10 adult, clinically normal dogs. Jitter was calculated as the mean absolute value of the consecutive differences in latency of 50 single muscle fiber action potentials after stimulation of intramuscular nerve bundles at the level of the motor point in at least 20 muscle fibers per muscle. Bilateral recordings were performed in 3 dogs. Mean jitter values were determined for each muscle, and differences among muscle groups and among dogs were compared. The upper limits of mean consecutive difference (mean plus 3 standard deviations) for the PL, ECR, and OO muscles were 21.94, 22.53, and 23.39 micros, respectively, and the upper limit of mean consecutive difference for individual muscle fibers in the respective fiber pools was 28.62, 36.39, and 35.68 micros. Jitter values for the ECR and OO were significantly higher than the jitter value for the PL muscle (P < .05). Significant differences among muscles or dogs or between sides were not observed for the ECR. Significant differences among dogs were observed for OO jitter values and were attributed to extremely low jitter values in 1 dog. Significant differences were demonstrated between sides for the PL and were attributed to small sample size. Results of this study provide normative data that can be used in the application of the stimulated SFEMG technique to dogs with suspected disorders of neuromuscular transmission. 相似文献
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Brosnan RJ LeCouteur RA Steffey EP Imai A Kortz GD 《American journal of veterinary research》2002,63(9):1252-1256
OBJECTIVE: To develop a method for surgical placement of a commercial microsensor intracranial pressure (ICP) transducer and to characterize normal ICP and cerebral perfusion pressures (CPP) in conscious adult horses. ANIMALS: 6 healthy castrated male adult horses (1 Holsteiner, 1 Quarter Horse, and 4 Thoroughbreds). PROCEDURE: Anesthesia was induced and maintained by use of isoflurane as the sole agent. Catheters were inserted percutaneously into the jugular vein and carotid artery. A microsensor ICP transducer was inserted in the subarachnoid space by means of right parietal craniotomy. The burr hole was then sealed with bone wax, the surgical incision was sutured, and the transducer was secured in place. Measurements were collected 1 hour after horses were able to stand during recovery from anesthesia. RESULTS: Mean +/- SD values for ICP and CPP were 2 +/- 4 and 102 +/- 26 mm Hg, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: This report describes a relatively facile technique for obtaining direct and accurate ICP measurements for adult horses. The ICP values obtained in this study are within reference ranges established for other species and provide a point of reference for the diagnosis of abnormal ICP in adult horses. 相似文献
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Dickinson PJ Keel MK Higgins RJ Koblik PD LeCouteur RA Naydan DK Bollen AW Vernau W 《Veterinary pathology》2000,37(2):160-167
Two oligodendrogliomas in two domestic cats involved mainly the rostral brain stem, midbrain, fourth ventricle, and cerebellum. Both cats were aged neutered males presenting with clinical neurologic deficits suggestive of a brain stem lesion. Magnetic resonance imaging of both tumors demonstrated lesions with a pattern of heterogeneous contrast enhancement and multifocal lesions in one cat. Routine cerebrospinal fluid analysis was normal in one cat and suggestive of an inflammatory disease in the other. Oligodendroglioma cells were seen in cytospin preparations of cerebrospinal fluid from both cats. In each cat, the tumors occurred intraventricularly in the midbrain and fourth ventricle with aggressive intraparenchymal infiltration. There was extensive growth into the basilar subarachnoid space of the midbrain and brain stem in one cat. One tumor was well differentiated, and the other was an anaplastic subtype. Immunostaining for several myelin- and oligodendroglia-specific antigens was negative with formalin-fixed tumors and with unfixed frozen samples from one cat. In both tumors, component cells of the intratumoral vascular proliferations were positive for human von Willebrand factor VIII antigen or smooth muscle actin. Immunocytochemical reactivity for glial fibrillary acidic protein identified both reactive astrocytes and a subpopulation of minigemistocytes in both tumors. Ultrastructurally, the tumor cells were unremarkable except for their prominent desmosomal junctions and paucity of microtubules. 相似文献
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Karen M Vernau Anna Osofsky Richard A LeCouteur 《Veterinary Clinics of North America: Exotic Animal Practice》2007,10(3):731-58, v
Completion of a thorough neurological examination of a rabbit is essential for clinicians to determine the location of a neurological problem. Determination of the location of a lesion (whether solitary or multifocal/diffuse) enables a clinician to list the most likely causes of the problem. This article presents the neurological examination of the rabbit, followed by a practical guide to lesion localization in this species. 相似文献
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Expression of receptor tyrosine kinases VEGFR-1 (FLT-1), VEGFR-2 (KDR), EGFR-1, PDGFRa and c-Met in canine primary brain tumours 总被引：1，自引：0，他引：1
P. J. Dickinson B. N. Roberts R. J. Higgins C. M. Leutenegger A. W. Bollen P. H. Kass R. A. LeCouteur 《Veterinary and comparative oncology》2006,4(3):132-140
Inhibition of tumour growth and angiogenesis by targeting key growth factor receptors is a promising therapeutic strategy for central nervous system tumours. Characterization of these growth factor receptors in canine primary brain tumours has not been done. Using quantitative real‐time TaqMan polymerase chain reaction (PCR), we evaluated the expression of messenger RNA (mRNA) for five tyrosine kinase growth factor receptors (vascular endothelial growth factor receptor [VEGFR]‐1, VEGFR‐2, endothelial growth factor receptor [EGFR]‐1, platelet‐derived growth factor receptor a [PDGFRa], and c‐Met) relative to normal cerebral cortex in 66 spontaneous canine primary brain tumours. Increased expression of VEGFR‐1 and VEGFR‐2 mRNA was greatest in grade IV astrocytomas (glioblastoma multiforme) and grade III (anaplastic) oligodendrogliomas. EGFR‐1 mRNA expression was more consistently increased than the other receptors in all tumour types, while increased PDGFRa mRNA expression was mostly restricted to oligodendrogliomas. The similarities in increased expression of these tyrosine kinase growth factor receptors in these canine tumours, as compared to data from their human counterparts, suggest that common molecular mechanisms may be present. 相似文献
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Brosnan RJ LeCouteur RA Steffey EP Imai A Farver TB 《American journal of veterinary research》2004,65(8):1042-1046
OBJECTIVE: To determine whether high intracranial pressure (ICP) during spontaneous ventilation (SV) in anesthetized horses coincides with an increase in intracranial elastance (ie, change in ICP per unit change of intracranial volume). ANIMALS: 6 adult horses. PROCEDURE: Anesthesia was induced and maintained in each horse for 5 hours with isoflurane at a constant dose equal to 1.2 times the minimum alveolar concentration. Direct ICP measurements were obtained by use of a strain gauge transducer inserted in the subarachnoid space, and arterial blood pressure was measured from a carotid artery. Physiologic responses were recorded after 15 minutes of normocapnic controlled ventilation (CV) and then after 10 minutes of SV. Aliquots (3 mL) of CSF were removed from each horse during SV until ICP returned to CV values. Slopes of pressure-volume curves yielded intracranial elastance. RESULTS: Intracranial elastance ranged from 0.2 to 3.7 mm Hg/mL after removal of the first aliquot of CSF Slopes of pressure-volume curves were largest following removal of the initial CSF aliquot, but shallow portions of curves were detected at relatively high ICPs (25 to 35 mm Hg). A second-order relationship between SV ICP and initial intracranial elastance was found. CONCLUSIONS AND CLINICAL RELEVANCE: In horses anesthetized with isoflurane, small changes in intracranial volume can cause large changes in ICP Increased intracranial elastance could further exacerbate preexisting intracranial hypertension. However, removal of small volumes of CSF may cause rapid compensatory replacement from other intracranial compartments, which suggests steady-state maintenance of an increase in intracranial volume during isoflurane anesthesia in horses. 相似文献
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Cona C. Anwer Karen M. Vernau Robert J. Higgins Peter J. Dickinson Beverly K. Sturges Richard A. LeCouteur R. Timothy Bentley Erik R. Wisner 《Veterinary radiology & ultrasound》2013,54(3):271-277
Magnetic resonance (MR) imaging characteristics of intracranial granular cell tumors (GCTs) have been previously reported in three dogs. The goal of this retrospective study was to examine a larger number of dogs and determine whether distinctive MR characteristics of intracranial GCTs could be identified. Six dogs with histologically confirmed intracranial GCTs and MR imaging were included. Tumor location, size, mass effect, T1‐ and T2‐weighted signal intensity, and peritumoral edema MR characteristics were recorded. In all dogs, GCTs appeared as well‐defined, extra‐axial masses with a plaque‐form, sessile distribution involving the meninges. All tumors were located along the convexity of the cerebrum, the falx cerebri, or the ventral floor of the cranial vault. All tumors were mildly hyperintense on T1‐weighted images, and iso‐ to hyperintense on T2‐weighted images. A moderate‐to‐severe degree of peritumoral edema and mass effect were evident in all dogs. Findings indicated that, while several MR imaging characteristics were consistently identified in canine cerebral GCTs, none of these characteristics were unique or distinctive for this tumor type alone. 相似文献