Effects of aging on brainstem responses to toneburst auditory stimuli: a cross-sectional and longitudinal study in dogs.

Background: It is assumed that the hearing of dogs becomes impaired with advancing age, but little is known about the prevalence and electrophysiologic characteristics of presbycusis in this species.

Hypothesis: As in humans, hearing in dogs becomes impaired with aging across the entire frequency range, but primarily in the high-frequency area. This change can be assessed quantitatively by brainstem-evoked response audiometry (BERA).

Assessment of decompressive surgery in dogs with degenerative lumbosacral stenosis using force plate analysis and questionnaires.

Objective: To evaluate the long-term outcome after decompressive surgery in dogs with degenerative lumbosacral stenosis (DLS), using force plate analysis (FPA) and owner questionnaires.

Study Design: Prospective clinical study.

Animals: Dogs with DLS (n=31) and 24 clinically normal Labrador Retrievers.

Comparison of the effects of firocoxib, carprofen and vedaprofen in a sodium urate crystal induced synovitis model of arthritis in dogs.

A randomized, placebo-controlled, four-period cross-over laboratory study involving eight dogs was conducted to confirm the effective analgesic dose of firocoxib, a selective COX-2 inhibitor, in a synovitis model of arthritis. Firocoxib was compared to vedaprofen and carprofen, and the effect, defined as a change in weight bearing measured via peak ground reaction, was evaluated at treatment dose levels. A lameness score on a five point scale was also assigned to the affected limb.

Hepatic (64)Cu excretion in Dobermanns with subclinical hepatitis.

To investigate whether Dobermanns have impaired copper excretion an intravenous radioactive copper isotope ((64)Cu) was used as a tracer. Five patients and eight normal dogs (5 normal Dobermanns and 3 Beagles) were studied. The five female Dobermann patients had a subclinical hepatitis and an increased hepatic copper concentration (median 822mg/kg, range 690-1380mg/kg dry matter).

Tibial nerve somatosensory evoked potentials in dogs with degenerative lumbosacral stenosis.

Objective: To determine somatosensory evoked potentials (SEPs) in dogs with degenerative lumbosacral stenosis (DLS) and in healthy dogs.

Study Design: Clinical and experimental study.

Animals: Dogs with DLS (n = 21) and 11 clinically normal dogs, age, and weight matched.

Force plate analysis before and after dorsal decompression for treatment of degenerative lumbosacral stenosis in dogs.

Objective: Using force plate analysis (FPA), determine ground reaction forces in dogs with degenerative lumbosacral stenosis (DLS) and evaluate the effects of lumbosacral decompressive surgery.

Study Design: Prospective clinical study.

Animals: Twelve dogs with DLS.

Differences between somatosensory-evoked potentials recorded from the ventral posterolateral thalamic nucleus, primary somatosensory cortex and vertex in the rat.

Somatosensory-evoked potential (SEP) components recorded over the primary somatosensory cortex (SI) and vertex in the rat within the 10-30 ms latency range were characterised with respect to the anatomy and function of the primary somatosensory pathway. To this aim, these components were compared to SEP components in the similar latency range recorded from the ventral posterolateral thalamic (VPL) nucleus, a nucleus known to be part of the subcortical structure of the primary somatosensory pathway and were described with respect to their stimulus-response characteristics and their response to the mu-opioid agonist fentanyl. The VPL positive (P)11-negative (N)18-P22 and SI P13-N18-P22 differed with respect to peak occurrence (P11 versus P13, respectively) and waveform morphology, but did not differ with respect to stimulus-response characteristics and their response to fentanyl.

Plasma 14C-cholic acid clearance in healthy dogs and dogs with cholestasis or a congenital portosystemic shunt.

The clearance profiles of intravenously injected tracer doses of radioactively labelled cholic acid were investigated in healthy dogs, dogs with a congenital portosystemic shunt and dogs with cholestasis. The rate constants and residual plasma activity were significantly different in the healthy and diseased dogs, but it was not possible to differentiate between the dogs with portosystemic shunting and cholestasis because the results were determined not only by factors involved in plasma bile acid clearance but also by the enterohepatic circulation.

Inherited congenital extrahepatic portosystemic shunts in Cairn terriers.

The pathogenesis of congenital portosystemic shunt (CPSS) in dogs still is incompletely understood. In Irish Wolfhounds and Yorkshire Terriers, CPSS is reported to be hereditary. The aim of this study was to investigate a possible genetic basis and the mode of inheritance of CPSS in Cairn Terriers.

Effect of octreotide on plasma concentrations of glucose, insulin, glucagon, growth hormone, and cortisol in healthy dogs and dogs with insulinoma.

The inhibitory effect of the somatostatin analogue octreotide on the secretion of insulin could be used in the treatment of insulinoma. However, current information on the effectiveness of octreotide in dogs is conflicting. Therefore, the endocrine effects of a single subcutaneous dose of 50 microg octreotide were studied in healthy dogs in the fasting state (n=7) and in dogs with insulinoma (n=12).

Differences between primary somatosensory cortex- and vertex-derived somatosensory-evoked potentials in the rat.

The somatosensory-evoked potential (SEP) elicited by high-intensity stimulation potentially provides a reliable indicator of analgesic efficacy since it reflects the level of activation of the nociceptive system. In the present study, components in the 10-30-ms latency range of SEPs recorded over the primary somatosensory cortex (SI-SEPs) and vertex (Vx-SEP) in the rat were characterized and compared. SEPs were elicited by electrical tail-base stimulation, and SI-SEPs and Vx-SEPs were recorded simultaneously.

Immunophenotyping of the cutaneous cellular infiltrate after atopy patch testing in cats with atopic dermatitis.

Cats with spontaneously occurring atopic dermatitis have clinical and immunocytochemical characteristics compatible with these in humans with atopic dermatitis (AD). The atopy patch test (APT) has proven to be a valuable tool in elucidating the disease process in humans. Additionally, the APT is very specific and bypasses the problem of conflicting results due to differences in chronicity of lesions of AD patients.

Middle-latency auditory-evoked potential in acepromazine-sedated dogs.

The middle-latency auditory-evoked potential (MLAEP) has been investigated as means of monitoring anesthesia in dogs. The goals of this study were to develop a technique to record MLAEPs in awake dogs and to determine the effects of sedation. The MLAEP was recorded in 12 dogs with and without sedation with acepromazine.

Growth hormone modulates cholecalciferol metabolism with moderate effects on intestinal mineral absorption and specific effects on bone formation in growing dogs raised on balanced food.

The aim of the study was to investigate the influence of growth hormone (GH) on Vitamin D3 metabolism and the subsequent effects on calcium (Ca) homeostasis and skeletal growth in growing dogs. A group of Miniature Poodles received supraphysiological doses of GH (GH group; n = 6; 0.5 IU GH per kg body per day) from 12 to 21 weeks of age and was compared with a control placebo-treated group (n = 8).

Hormonal regulation of calcium homeostasis in two breeds of dogs during growth at different rates.

Growing giant-breed dogs are more susceptible to developing skeletal disorders than small-breed dogs when raised on diets with deficient or excessive Ca content. Differential hormonal regulation of Ca homeostasis in dogs with different growth rates was investigated in Great Danes (GD, n = 9) and Miniature Poodles (MP, n = 8). All animals were raised on the same balanced diet and under identical conditions.

Evaluation of methods for eliciting somatosensory-evoked potentials in the awake, freely moving rat.

To standardise the method of eliciting somatosensory-evoked potentials (SEPs), SEPs were generated by electrical stimulation of different stimulus sites and recorded bilaterally from the primary somatosensory cortex (S1) and from midline in awake, freely moving rats. Increasing stimulus intensity enhanced amplitudes of all SEPs. At supramaximal stimulation, SEPs following vibrissae and tail stimulation (V-SEP and Ta-SEP, respectively) but not following trunk stimulation (Tr-SEP), fulfilled our criterion of signal-to-noise ratio >or=4.

Dietary 135-fold cholecalciferol supplementation severely disturbs the endochondral ossification in growing dogs.

The effects of excessive non-toxic dietary Vitamin D(3) supplementation on Ca homeostasis with specific effects on endochondral ossification and skeletal remodeling were investigated in a group of growing Great Dane dogs supplemented with cholecalciferol (Vitamin D(3); HVitD) versus a control group (CVitD) (1350 microg versus 11.4 microg Vitamin D(3) per kilogram diet) from 6 to 21 weeks of age. There were no differences between groups in plasma concentrations of total Ca, inorganic phosphate, growth hormone, and insulin-like growth factor I and no signs of Vitamin D(3) intoxication in HVitD.

Reduced dosage of ketoprofen for the short-term and long-term treatment of joint pain in dogs.

Two studies were conducted under laboratory conditions with 16 dogs to investigate the analgesic effectiveness of a low dose of ketoprofen in a short-term sodium urate crystal-induced synovitis model of arthritis. The effect of the treatment, defined as the improvement in peak vertical force weight bearing was evaluated in the first study at three dose levels. A single oral dose of 0.

24-Hydroxylase: potential key regulator in hypervitaminosis D3 in growing dogs.

A group of growing dogs supplemented with cholecalciferol (vitamin D(3); HVitD) was studied vs. a control group (CVitD; 54,000 vs. 470 IU vitamin D(3)/kg diet, respectively) from 3 to 21 wk of age.

Intestinal calcium absorption in growing dogs is influenced by calcium intake and age but not by growth rate.

The effects of calcium (Ca) intake (V(I)), age and growth rate on intestinal Ca absorption were studied in growing dogs. Two breeds of dogs differing in their growth rate (67 Great Danes and 23 Miniature Poodles) were raised on diets differing only in their Ca content (range 0.33 to 3.

Moderate cholecalciferol supplementation depresses intestinal calcium absorption in growing dogs.

Hormonal regulation of calcium (Ca) absorption was investigated in a cholecalciferol (vitamin D(3))-supplemented group (hVitD) vs. a control group (cVitD) of growing Great Danes (100 vs. 12.

Click and low-, middle-, and high-frequency toneburst stimulation of the canine cochlea.

A method was developed to deliver tonebursts ranging in frequency from 1 to 32 kHz for frequency-specific assessment of the canine cochlea. Brainstem auditory-evoked responses (early latency responses, 0-10 ms) to a click (CS) and to 1-, 2-, 4-, 8-, 12-, 16-, 24-, and 32-kHz toneburst stimulations (TS) were compared at 80-dB sound pressure level stimulus (SPL) intensity in 10 adult dogs. All stimulations yielded a 5-7 positive wave pattern, with the exception of the 1-kHz TS, which evoked a frequency-following response (FFR).

Influence of litter size and breed on the duration of gestation in dogs.

The variation in the duration of gestation, defined as the period from mating to parturition, was studied in 113 bitches of six breeds (31 Dobermans, 31 Labrador retrievers, 14 German shepherds, 13 Bernese mountain dogs, 12 golden retrievers and 12 West Highland white terriers). The bitches were mated once on the optimal day for mating, which was established by measuring the plasma concentration of progesterone. The duration of gestation varied between 58 and 65 days with a mean of 61.

The rat vertex-middle latency auditory-evoked potential as indicator of anaesthetic depth: a comparison with evoked-reflex testing.

We investigated whether components from the rat Vx-MLAEP could be used to assess depth of anaesthesia induced by propofol. Propofol decreased MLAEP amplitudes and increased latencies. We propose that the P(16)-N(22) wave in the rat MLAEP is similar to the human P1, and that recovery of this wave during propofol anaesthesia correlates with behavioural measures of the regaining of consciousness.

EEG evaluation of reflex testing as assessment of depth of pentobarbital anaesthesia in the rat.

Electroencephalography (EEG) was applied to evaluate the validity of the paw pinch reflex as an indicator of anaesthetic depth in rats which are anaesthetized with a single intraperitoneal dose of pentobarbital. After induction of the anaesthesia, characterized by the rapid loss of the animals' ability to maintain upright posture, the EEG of 10 out of 11 rats was dominated by paroxysmal (burst suppression) activity, associated with unconsciousness. In seven out of 11 rats, the paw pinch reflex was lost after onset of paroxysmal electroencephalographic activity.