Post-operative computed tomography (CT) has been described as a technique for diagnosing incomplete resection or recurrence of cerebral neoplasms in humans. The characteristics of immediate postoperative CT images in dogs with intracranial pathology are unknown. This report describes findings from preoperative, immediate post-operative, and 4 week to 9 month follow-up CT examinations in two dogs with histologically-confirmed cerebral meningiomas. In images of one dog after surgery there was mild contrast enhancement of the tissue surrounding the surgical site. This enhancement had resolved in later images and was probably the result of surgically induced trauma. In post operative images of the other dog there was significant hyperattenuation of the tissues around the surgical site. In post contrast images there was increased enhancement that was evident in later images. These findings, although not supported by necropsy, probably indicate incomplete excision of the tumor.

Brain stem auditory evoked potentials (BAEP) and somatosensory evoked potentials (SEP), recorded from subcutaneously placed electrodes in anesthetized rats, were used to detect neurotoxic effects of acrylamide and 2,5-hexanedione on the sensory nervous system. Both neurotoxicants were administered for 21 days by the intraperitoneal route, using dosages of 20 mg/kg/day for acrylamide and 350 mg/kg/day for 2,5-hexanedione, Recordings were made before and 1, 2, and 3 weeks after dosing was initiated. Both food-restricted and ad libitum-fed rats served as controls. Results demonstrated that SEP waveforms generated in rats were sufficiently variable that differences among the groups were not detected, However, BAEP latencies were longer than those seen in control rats after 3 weeks of acrylamide treatment and after both 2 and 3 weeks of 2,5-hexanedione treatment. The effects of 2,5-hexanedione were more pronounced than those of acrylamide, and increased with length of the dosing period.

OBJECTIVE:To study biomechanical characteristics of the normal and surgically altered canine thoracolumbar vertebral column to determine the effects of surgery and trauma on lateral stability.ANIMALS:The T13-L1 vertebral motion units of 48 mixed-breed dogs were dissected free of surrounding musculature and prepared for biomechanical testing by cross-pinning the vertebral bodies and mounting in polymethylmethacrylate.PROCEDURE:Normal and surgically altered spinal specimens were subjected to lateral bending. The mean slope of the bending moment versus angular displacement curve and the load to failure were compared between treatment groups and significance was determined by the method of least squares (P < 0.05). Specimens were surgically altered by facetectomy, lateral fenestration, diskectomy, and combinations of these procedures. Each specimen was subjected to lateral bending to failure at a rate of 2.5 cm/min in a swing arm bending jig designed to simulate 4-point bending and subject the specimen to pure bending.RESULTS:Only specimens undergoing diskectomy had a significant decrease in slope and load at failure. Unilateral and bilateral facetectomies and fenestration induced a nonsignificant decrease in stiffness, compared with control specimens.CONCLUSIONS:Fenestrations and facetectomies do not appear to increase the risk of injury to the canine thora-columbar spinal cord during lateral bending.CLINICAL RELEVANCE:Fenestrations and facetectomies, as used in routine laminectomies, may be performed without concern for significant destabilization of the spine in lateral bending; however, it is possible that thoracolumbar spinal fractures involving only the vertebral body may significantly destabilize the spine in all modes of bending.

Sacral fractures have not been described well in dogs. The records of 32 dogs diagnosed with sacral fractures were evaluated for neurologic deficits at presentation and discharge. Follow-up was in the form of telephone survey or physical examination at recheck. A score was assigned for each dog at presentation, discharge, and follow-up (0 for normal, 1 for minor deficits, and 2 for major deficits). Fractures located lateral to the sacral foramina were called abaxial, and those medial to the sacral foramina were called axial. Axial fractures had significantly more severe deficits at presentation (p = 0.00017) and discharge (p = 0.03063), but not at follow-up. Neurologic status did not improve significantly during hospitalization in either fracture group, but had improved significantly at follow-up.

Fluoroscopic-guided cranial lumbar spinal cord aspiration was performed on seven normal, anesthetized dogs. The normal lumbar spinal cord cytology was described. All dogs recovered without observable neurologic damage. Lumbar spinal cord fine needle aspiration appears to have no detrimental effects in normal dogs.

Two red-tailed hawks (Buteo jamaicensis), found near Deltaville, Virginia (USA), were evaluated because of inability to use a wing. Results of needle electromyographic studies of the affected wing muscles in both hawks were compatible with denervation. On euthanasia, one hawk had extensive axon and myelin loss with multifocal perivascular lymphocytic inflammation of its brachial plexus and radial nerve. Demyelination and axon loss in the dorsal white matter of the spinal cord on the affected side also were found at the origin of the brachial plexus. The other hawk's wing had not returned to functional status >2 yr after injury.

Adult male Long Evans rats were given a single administration of 3 dosage levels of the organophosphorus compounds tri-ortho-tolyl phosphate (TOTP), diisopropyl fluorophosphate (DFP), phenyl saligenin phosphate (PSP), mipafox, malathion, and dichlorvos or the carbamate carbaryl. Acetylcholinesterase and neurotoxic esterase activities were inhibited in a dose-dependent manner, with the highest dosages of all of these compounds inhibiting activities of these enzymes in brain by at least 37% and 64%, respectively, at 4 and 48 hours after administration. Rats given the high doses of TOTP (1000 mg/kg), DFP (3 mg/kg), malathion (2000 mg/kg), and carbaryl (160 mg/kg) weighed significantly less than control rats 14 days after administration. A functional observational battery (FOB) was used to screen for neurotoxic effects 1, 2, and 3 weeks after exposure. All 7 test compounds were capable of causing changes in parameters indicative of behavioral and central nervous system excitability. In addition, dose-related alterations in response to approach were seen in rats given DFP, malathion, dichlorvos, and carbaryl. Mild to moderate myelinated fiber degeneration was seen in the rostral levels of the fasciculus gracilis in rats given TOTP, DFP, PSP and mipafox, but no significant neuropathologic lesions were noted in rats given dichlorvos, malathion, or carbaryl.

A gram-negative coccobacillus was isolated from the lower respiratory tract of a cat with chronic obstructive pulmonary disease. The isolate required CO2 and V factor for growth and was initially identified as Haemophilus paraphrophilus on the basis of its nutritional requirements, colony morphology, and some biochemical tests. Because of the host specificity of Haemophilus species and discrepancies in catalase, oxidase, and hemolytic activities, additional testing was done. Extensive biochemical testing, G+C content, and DNA reassociation studies indicated that the organism was distinct from other Haemophilus species. Therefore, the organism was identified as a previously unrecognized Haemophilus species and was tentatively named "Haemophilus felis." Bacteria identical to the original isolate were isolated from the nasopharynxes of 6 of 28 apparently normal cats, indicating that H. felis or H. felis-like organisms may be common members of the feline upper respiratory tract flora.