Biomechanical Evaluation of a Crimp Clamp System for Loop Fixation of Monofilament Nylon Leader Material Used for Stabilization of the Canine Stifle Joint

Objective —To test a crimp clamp system designed to secure monofilament nylon leader (MNL) material commonly used as lateral fabellotibial sutures (LFS) in extra-articular stabilization of the canine stifle joint.
Study Design — In vitro biomechanical tests of MNL loops secured with either the crimp clamp system or knots were performed. Suture loops (n = 94) were created from 27.3 kg tensile strength MNL and fastened with knots or crimp clamps. Tests were conducted on steam-sterilized, ethylene-oxide-sterilized, and nonsterilized MNL sutures. Loops were evaluated in single load tests and cycled tests. Values for load to failure, initial loop tension, loop elongation, mode of failure, and point of failure were determined.
Results —Crimp-clamped loops were superior to knotted loops in all parameters tested in both cycled and noncycled tests. Loop failure generally occurred by breaking within 3 mm of the fixation in both clamped and knotted tests. Loop elongation after cycling was greater in the knotted loops compared with clamped loops ( P < .001). Load to failure was greater in clamped tests than in knotted tests (P < .001), regardless of sterilization technique used. Significantly higher initial loop tension could be achieved with the clamp system compared with knot fixation ( P < .001).
Conclusions —The crimp clamp system provides superior in vitro loop fixation characteristics compared with knot fixation in 27.3 kg test MNL.
Clinical Relevance —Based on the results of biomechanical testing and the known biocompatibility of the system's implant components, clinical trials using the crimp clamp system are warranted.     

Radiographic Progression of Osteoarthritis of the Canine Stifle Joint: A Prospective Study

A radiographic scoring system for features of osteoarthritis of the canine stifle joint was devised. Intra- and inter-rater agreement was assessed by calculation of unweighted kappa statistics. "Global score," "effusion," "osteophytosis," and "intra-articular mineralization" were all features that had acceptable reliability, but "subchondral sclerosis" did not. The scoring system was used in a 13-month prospective study of the radiographic progression of osteoarthritis of the stifle joint, secondary to cranial cruciate ligament deficiency, in 58 dogs. In the index stifle joints all features were characterized by significant change over time, but osteophytosis had the greatest degree of change. In addition, 40% of contralateral joints showed progressive osteophytosis.     

The Effect of Season on Semen Characteristics and Freezability in Bos indicus and Bos taurus Bulls in the Southeastern Region of Brazil

The objectives of this study were to evaluate the effects of season in southeast of Brazil comparing genotypes on semen characteristics, freezability and peripheral plasma concentrations of testosterone. Ejaculates of five Bos indicus bulls and six Bos taurus bulls were evaluated over a period of 27 months, which was divided into winter (July, August, September), spring (October, November, December), summer (January, February, March) and autumn (April, May, June). Semen was evaluated according to standard procedures for ejaculate volume, sperm concentration, gross-motility, progressive motility and sperm morphology. After preparing and freezing the ejaculates according to commercial procedures, the straws were stored in liquid N₂ until post-thaw evaluation. Ejaculate volume, sperm concentration, gross-motility, progressive sperm motility, vigor and morphological sperm defects were significantly influenced by season and genotype (p < 0.05). Heat tolerance was better in B. indicus bulls than in B. taurus bulls characterized by lower values of sperm abnormalities throughout the observation period. The highest values were recorded for abnormal heads followed by cytoplasmatic droplets in B. taurus bulls. The proportion of ejaculates which were eliminated before freezing for reasons of bad quality was lower in the B. indicus bulls. Temporal changes in peripheral plasma testosterone concentrations were higher in B. indicus bulls than in B. taurus bulls not revealing seasonal influences. The results of this study show clear genotype differences regarding semen quality. Freezability of B. taurus semen varies considerably throughout the year, leading to a high proportion of eliminated ejaculates. Collecting semen from B. taurus bulls during the summer in an artificial insemination centre may not be profitable.     

Partial Right Ventriculectomy Using the Incised Patch Technique to Treat Double Chambered Right Ventricle and Chylothorax in a Cat

Objective— To report successful surgical treatment of double chambered right ventricle (DCRV) in a cat.
Study Design— Clinical report.
Animals— Cat with DCRV.
Methods— DCRV was diagnosed in a 5-month-old male Maine Coon cat using echocardiography and angiocardiography. At 2 years, despite medical therapy, chylothorax developed. A section of the right ventricular free wall that spanned the fibromuscular obstruction was excised under total venous inflow occlusion (TVIO) using the incised pericardial patch technique.
Results— Short-term recovery was complicated by return of chylothorax but this resolved after thoracocentesis and diuretic therapy. Three years after surgery, the cat is free of clinical signs and no longer on any medical therapy.
Conclusions— Partial right ventriculectomy can be performed under TVIO through an incised pericardial patch.
Clinical Relevance— DCRV in cat can be successfully treated by partial right ventriculectomy performed under TVIO through an incised pericardial patch.     

RELATIONSHIP AMONG BASILAR ARTERY RESISTANCE INDEX, DEGREE OF VENTRICULOMEGALY, AND CLINICAL SIGNS IN HYDROCEPHALIC DOGS

Forty-four transcranial Doppler ultrasound studies were performed in 36 dogs. The ratio of the height of the ventricle to the height of the brain (VB ratio) was calculated to determine the severity of ventriculomegaly. Resistance index (RI) was calculated from Doppler measurements of the blood flow velocity in the basilar artery and neurologic signs were scored on a scale of 0 to 3. Based on clinical and ultrasonographic findings, dogs were divided into four groups (normal controls, asymptomatic hydrocephalus, symptomatic hydrocephalus, and other intracranial disease). RI and VB ratio were compared between the groups of dogs and compared with neurologic signs in hydrocephalic dogs. RI ranged from 0.50 to 0.81 (mean, 0.68). Resistance index was significantly higher in dogs with symptomatic hydrocephalus and other intracranial disease when compared with the other two groups. The degree of ventriculomegaly was significantly higher in dogs with symptomatic hydrocephalus than the other groups, but there was substantial overlap between asymptomatic and symptomatic hydrocephalus groups. Combining measurements of VB ratio and RI allowed detection of symptomatic hydrocephalus with a sensitivity of 77% and a specificity of 94%. The severity of neurological signs was significantly correlated with RI and with VB ratio in hydrocephalic dogs, and in dogs evaluated on more than one occasion, changes in neurologic status were accompanied by changes in RI but not in VB ratio. All asymptomatic hydrocephalic dogs with a VB ratio of greater than 60% eventually developed neurologic signs. Our results suggest that ultrasonographic measurement of VB ratio and basilar artery RI may allow identification of dogs with symptomatic hydrocephalus or dogs that are at risk of developing symptomatic hydrocephalus. Repeated RI measurements are a useful means of monitoring dogs with a variety of intracranial diseases.     

The use of repeated-measurements analysis to describe the overwintering of white clover cultivars

An experiment was set up to investigate the morphological and physiological changes occurring in two white clover (Trifolium repens) (clover) varieties, AberHerald and Huia, growing in binary mixture with two perennial ryegrass (Lolium perenne) (grass) varieties, Preference and Ba 10761. Measurements were made on four occasions during winter/spring 1993–94. The statistical procedure of antedependence analysis was used to check for the existence of serial correlations among data from the different sampling dates. Evidence of antedependence was found in only three of the seventeen variables measured, and an order of antedependence for each of these was estimated. The antedependence structure providing the best fit to the data was then used in an analysis of covariance on the data set for that variable. The rest of the seventeen variables could be safely analysed by a split-plot analysis of variance for each sampling date separately. This result validated the sampling protocol used in the experiment.     

Comparison of diazepam–ketamine and thiopentone for induction of anaesthesia in healthy dogs

Objective To compare the anaesthetic and cardiopulmonary effects of a diazepam–ketamine combination with thiopentone for induction of anaesthesia in dogs. Animal population Twenty healthy dogs of various breeds weighing between 3.8 and 42.6 kg undergoing major orthopaedic or soft tissue surgery. Materials and methods Pre‐anaesthetic medication in all cases was intramuscular acepromazine and methadone given 30 minutes before induction of anaesthesia. Each animal was then randomly assigned to receive either thiopentone or diazepam and ketamine. Quality of conditions for, and time to tracheal intubation were recorded. Anaesthesia was maintained with halothane in oxygen and nitrous oxide. Heart rate, respiratory rate, systolic blood pressure, end tidal carbon dioxide tensions and oxygen saturation were recorded at 10 minute intervals throughout surgery. The quality of recovery from anaesthesia was assessed. Results The quality of induction in both groups was satisfactory. The total mean time (± SD) to tracheal intubation (162 ± 84 seconds) was significantly longer in dogs receiving diazepam and ketamine compared to dogs receiving thiopentone (62 ± 28 seconds). Heart rate, systolic blood pressure and end tidal carbon dioxide concentration were not significantly different between groups. Respiratory rate was significantly higher in the diazepam–ketamine group between 0 and 30 minutes. The quality of recovery was similar in each group. Conclusions There appear to be fewer differences between the induction agents examined in this study than was previously believed. No pressor, or other cardiovascular stimulating effects were detected in the dogs that received diazepam and ketamine. Clinical relevance The absence of obvious differences between groups suggests that pre‐anaesthetic medication, inhaled anaesthetics and the physiological effects of surgery itself probably had a greater effect on the variables studied than the induction agent used. Further studies are required to determine whether diazepam and ketamine offers significant advantages over other induction agents in the unhealthy dog.