No abstract

Diabetic cataractous dogs have significantly altered keratoconjunctival characteristics compared to nondiabetic cataractous and nondiabetic noncataractous dogs.

The accurate measurement of behavioral compensation after CNS trauma, such as spinal cord injury, is important when assessing the functional effects of injury and treatment in animal models. We investigated the locomotor abilities of rats with unilateral thoracic or cervical spinal cord injuries using a locomotor rating (BBB) scale, reflex tests, and quantitative kinetic measurements. The BBB rating scale indicated that thoracic spinal hemisected (TH) rats had more severely affected hindlimbs compared to cervical spinal hemisected (CH) and sham-operated animals. Kinetic measurements revealed that CH and TH animals moved with different ground reaction force patterns, which nevertheless shared some similarities with each other and with the gait patterns of rats with different unilateral CNS lesions. Uninjured rats typically had an equal distribution of their body weight over the forelimbs and hind limbs, and used their forelimbs predominantly for braking while using their hind limbs mostly for propulsion. CH rats bore more weight on their hind limbs than their forelimbs, while TH animals bore more weight on their forelimbs than their hind limbs. Neither CH nor TH rats used the forelimb ipsilateral to the spinal hemisection for net braking or propulsion. The hindlimb contralateral to the hemisection was placed on the ground prematurely during the stride cycle for both CH and TH animals. The altered kinetics of the locomotor pattern in hemisected animals resulted in changes in the oscillations of total body potential and kinetic energies. These two forms of energy oscillate synchronously in intact locomoting rats, but were asynchronous during parts of the stride cycle in spinal hemisected animals. We conclude that rats develop a general compensatory response for unilateral CNS lesions, which may help stabilize the animal during locomotion.

No abstract

Behavioural recovery is one of the primary goals of therapeutic intervention in animal models of disease. It is necessary, therefore, to have the means with which to quantify pertinent behavioural changes in experimental animals. Nevertheless, the number and diversity of behavioural measures which have been used to assess recovery after experimental interventions often makes it difficult to compare results between studies. The present review attempts to integrate and categorize the wide variety of behavioural assessments used to measure recovery in spinal-injured rats. These categories include endpoint measures, kinematic measures, kinetic measurements, and electrophysiological measurements. Within this categorization, we discuss the advantages and disadvantages of each type of measurement. Finally, we make some recommendations regarding the principles for a comprehensive behavioural analysis after experimental spinal cord injury in rats.

The purpose of this study was to determine the importance of the rubrospinal pathway and the ascending components of the dorsal column for overground locomotion in adult, unrestrained rats. The dorsal column (excluding the corticospinal tract), the rubrospinal tract or both were damaged unilaterally in rats at the level of the upper cervical spinal cord. Behavioural analysis consisted of skilled locomotion (an evaluation of footslips during ladder walking), a paw usage task and the assessment of ground reaction forces during unrestrained locomotion. All lesioned animals used the forepaw ipsilateral to the lesions less while rearing. Animals with dorsal column injuries used the forelimb contralateral to the spinal injury significantly more while rearing compared with uninjured animals. All lesioned animals produced more footfalls while crossing the ladder compared with uninjured animals. All injuries, regardless of the pathway affected, resulted in significant alterations in body weight support and reduced braking forces from the forelimb ipsilateral to the injury during overground locomotion. Animals typically bore less weight on the hindlimb ipsilateral to the lesion compared with the hindlimb contralateral to the spinal injury. Taken together with previously published work, our data indicate that the rubrospinal and dorsal column pathways are important for forelimb support while rearing and for skilled locomotion. Additionally, the ascending dorsal column pathways and the rubrospinal tract play a role during flat surface overground locomotion and combined damage to these pathways does not alter the acquired gait.

Intraspinal cysts of the L6-L7 and L7-S1 articular process joints in a six-year-old neutered female German Shepherd Dog were diagnosed using magnetic resonance (MR) imaging. Histopathology provided a diagnosis of ganglion cysts. Clinical, laboratory, radiographic and MR imaging findings are described. Briefly, radiographic findings revealed lumbarization of the first sacral vertebra, and fusion of the first caudal vertebra to the sacrum. In addition, spondylosis and articular process osteoarthrosis occurred at L6-L7 and L7-S1. MR imaging revealed multiple, well encapsulated structures ranging in size from 3-10 mm in diameter which were found to arise from the L6-L7 and L7-S1 articular process joints. These cysts had signal intensities that varied from hyperintense to the cerebrospinal fluid (CSF) on T1 weighted images to isointense to CSF on T2 weighted images. Decompressive surgery in conjunction with arthrodesis of these joints resulted in resolution of clinical signs. The dog remained pain-free 1 1/2 years following surgical therapy.

Traumatic neuroma in continuity (NIC) results in profound neurological deficits, and its management poses the most challenging problem to peripheral nerve surgeons today. The absence of a clinically relevant experimental model continues to handicap our ability to investigate ways of better diagnosis and treatment for these disabling injuries. Various injury techniques were tested on Lewis rat sciatic nerves. Optimal experimental injuries that consistently resulted in NIC combined both intense focal compression and traction forces. Nerves were harvested at 0, 5, 13, 21, and 65 days for histological examination. Skilled locomotion and ground reaction force (GRF) analysis were performed up to 9 weeks on the experimental (n=6) and crush-control injuries (n=5). Focal widening, disruption of endoneurium and perineurium with aberrant intra- and extrafascicular axonal regeneration and progressive fibrosis was consistently demonstrated in 14 of 14 nerves with refined experimental injuries. At 8 weeks, experimental animals displayed a significantly greater slip ratio in both skilled locomotor assessments, compared to nerve crush animals (p<0.01). GRFs of the crush- injured animals showed earlier improvement compared to the experimental animals, whose overall GRF patterns failed to recover as well as the crush group. We have demonstrated histological features and poor functional recovery consistent with NIC formation in a rat model. The injury mechanism employed combines traction and compression forces akin to the physical forces at play in clinical nerve injuries. This model may serve as a tool to help diagnose this injury earlier and to develop intervention strategies to improve patient outcomes.