Use of magnetic motor-evoked potentials in horses with bilateral hind limb ataxia

OBJECTIVE: To determine the usefulness of magnetic motor-evoked potentials (MMEPs) for assessing the integrity of the cervical, thoracic, and thoracolumbar spinal cord in horses with bilateral hind limb ataxia. ANIMALS: 9 horses and 1 donkey with bilateral hind limb ataxia of various degrees. PROCEDURE: The motor cortex was stimulated magnetically, and MMEPs were recorded bilaterally from the extensor carpi radialis and cranial tibial muscles. RESULTS: In 5 horses and 1 donkey, MMEPs with normal onset latencies and peak-to-peak amplitude were recorded from the extensor carpi radialis muscles, whereas abnormal onset latencies and peak-to-peak amplitudes were recorded from the cranial tibial muscles. In these animals, a spinal cord lesion in the thoracic or thoracolumbar segments was suspected. In 4 horses, onset latencies and peak-to-peak amplitude of MMEPs recorded from the extensor carpi radialis and cranial tibial muscles were abnormal. In these horses, a cervical spinal cord lesion was suspected. CONCLUSIONS AND CLINICAL RELEVANCE: Transcranial magnetic stimulation can be considered a valuable diagnostic tool for assessing the integrity of the spinal cord, and MMEPs may be used for differentiating thoracic or thoracolumbar spinal cord lesions from mild cervical spinal cord lesions that cause ataxia in the hind limbs only.     

Evaluation of a method to experimentally induce colic in horses and the effects of acupuncture applied at the Guan-yuan-shu (similar to BL-21) acupoint

OBJECTIVE: To evaluate the reliability of a method for inducing colic via small intestinal distention in horses and to examine the analgesic potential of bilateral electroacupuncture (EAP) at the Guan-yuan-shu (similar to BL21) acupoint. ANIMALS: 5 healthy adult horses, each with a gastric cannula. PROCEDURE: A polyester balloon connected to an electronic barostat was introduced into the duodenum via the gastric cannula. At 2 specified intervals (before and after commencement of EAP), the balloon was inflated to a barostat-controlled pressure that induced signs of moderate colic. Each inflation was maintained for 10 minutes. Heart and respiratory rates were continuously recorded. Frequency of various clinical signs of colic was recorded by 2 trained observers during various combinations of balloon inflation and EAP. Each horse received each of 5 treatment protocols (EAP at 20 Hz, sham EAP at 20 Hz, EAP at 80: 120 Hz dense:disperse, sham EAP at 80: 120 Hz dense:disperse, no treatment). Sham EAP was at a point located 2 cm lateral to the Guan-yuan-shu acupoint. RESULTS: Duodenal distention consistently induced a significant increase in frequency of signs of colic. None of the EAP protocols caused a significant reduction in frequency of these clinical signs during distention. CONCLUSIONS AND CLINICAL RELEVANCE: The method described is reproducible and highly controllable method for inducing colic that involved duodenal distention that should be useful in evaluating the efficacy of various analgesic strategies. Bilateral EAP at the Guan-yuan-shu acupoint was ineffective in reducing signs of discomfort induced by this method.     

Development of a competitive enzyme-linked immunosorbent assay for detection of turkey coronavirus antibodies

A competitive enzyme-linked immunosorbent assay (cELISA) was developed for detection of turkey coronavirus (TCV) antibodies. The cELISA utilized a recombinant baculovirus (Autographa californica nuclear polyhedrosis virus)-expressed TCV nucleocapsid (N) protein and biotin-labeled TCV N protein-specific monoclonal antibody. Sensitivity and specificity of the cELISA for detection of TCV antibodies were determined by comparison with the indirect fluorescent antibody test (IFAT) with 1269 reference, experimentally derived, and field-origin sera. Sera with discordant cELISA and IFAT results were further evaluated by western immunoblot analyses. The cELISA detected antibodies specific for TCV and infectious bronchitis virus, a closely related coronavirus, but did not detect antibodies specific for other avian viruses. A high degree of concordance was observed between the cELISA and IFAT; sensitivity and specificity of the cELISA relative to IFAT were 92.9% and 96.2%, respectively. Western immunoblot analyses provided additional evidence of cELISA specificity. The findings indicate that the cELISA is a rapid, sensitive, and specific serologic test for detection of TCV antibodies in turkeys.     

Efficacy and Toxicity of Doxorubicin and Cyclophosphamide Used in the Treatment of Selected Malignant Tumors in 23 Cats

Twenty-three cats with malignant, nonhematopoietic tumors were treated with doxorubicin and cyclophosphamide. Fourteen cats had nonresectable tumors of the mammary gland, and nine had tumors of the oral cavity. Of the cats with mammary gland adenocarcinoma, seven cats had a partial response to treatment and seven cats had no response. Of the cats with oral tumors, one cat had a complete response, three cats had a partial response, and five cats had no response. All 23 cats are dead because of tumor progression or recurrence. Toxic effects were seen in 18 of the cats; most were transient and required no alteration in the treatment protocol. A high response rate combined with acceptable toxicity warrants further evaluation of combination doxorubicin and cyclophosphamide chemotherapy in cats with nonhematopoietic neoplasia.     

Reactivation of latent pseudorabies virus infection in vaccinated commercial sows

Pseudorabies virus (PRV) was isolated from 9 of 44 PRV-vaccinated seropositive sows on 5 of 11 farms. Although serum-neutralization antibody titers were 1:16 to 1:256, 28 virus isolates were obtained from tonsil, nasal, or buccal swab samples from 9 sows given 2 ml of dexamethasone/kg of body weight IM for 5 days. Pseudorabies virus was isolated from 6 of 20 sows (3 of 5 farms) given a killed-virus vaccination. Virus was obtained from 3 of 24 sows (2 of 6 farms) given modified-live virus and killed-virus vaccination. Evaluation of the 9 PRV with 5 restriction endonucleases revealed 4 PRV existing genotypes. The 9 isolated types of PRV appeared to be indistinguishable by Kpn I and BamHI restriction endonuclease analysis; however, when analyzed with Sal I, HinfI, and Pst I, isolates 7 (farm D), 8 (farm C), and 9 (farm B) had numerous differences. Isolates 1, 2, 3, and 4 (farm F) and 5 and 6 (farm G) appeared to be the same genotype when further analyzed with Pst I, HinfI, and Sal I.     

In vitro susceptibility of feline herpesvirus-1 to vidarabine, idoxuridine, trifluridine, acyclovir, or bromovinyldeoxyuridine

In vitro activities of 9-[( 2-hydroxyethoxy] methyl) guanine (acyclovir), (E)-5-(2-bromovinyl)-2'deoxyuridine, 9-beta-D-arabinofuranosyladenine (vidarabine), 5-iodo-2'-deoxyuridine (idoxuridine), and 5-trifluoromethyl-2'-deoxyuridine (trifluridine) were studied against 6 strains of feline herpesvirus-1. A significant difference was not detected among viral strains in their susceptibility to these compounds (P = 0.442). The relative potency of these compounds was trifluridine much greater than idoxuridine greater than vidarabine greater than bromovinyldeoxyuridine much greater than acyclovir. Concentrations of trifluridine and idoxuridine (0.67 and 6.8 microM, respectively) required to reduce plaque numbers by 50%, compared with that of controls, were significantly lower (P less than 0.001) than were those of other compounds.     

Intestinal and bursal cryptosporidiosis in turkeys following inoculation with Cryptosporidium sp. isolated from commercial poults

Cryptosporidium meleagridis oocysts, originally isolated from droppings of commercial turkey poults with increased mortality due to viral (reovirus) hepatitis and enteritis, were treated with peracetic acid to kill companion bacteria and viruses and then propagated by passage in young turkeys. Thirty-eight 5-day-old large white turkey poults were inoculated by crop gavage with 500,000 cryptosporidial oocysts and compared with 40 uninoculated poults. Cryptosporidial oocysts shedding began 3 days postinoculation (PI), peaked on day 4 PI, and persisted at a low level for the duration of the 21-day trial. Low to moderate cryptosporidial infections of the ileal mucosa (days 3, 6, and 15 PI), cecal mucosa (days 3, 6, and 21 PI), and bursa of Fabricius (days 6, 12, 15 and 21 PI) were found on histopathological examination. There were no differences in mean body weights between the inoculated and uninoculated groups, and no mortality or clinical signs of disease were seen in either group.