Intraoperative changes in blood pressure, heart rate, plasma vasopressin, and urinary noradrenalin during elective ovariohysterectomy in dogs: repeatability at removal of the 1st and 2nd ovary.

OBJECTIVE: To investigate the physiologic reactions after removal of 1st ovary and whether this is repeated during removal of the 2nd ovary in elective ovariohysterectomy. STUDY DESIGN: Prospective study. ANIMALS: Dogs (n = 10). METHODS: Dogs were premedicated with acepromazine, carprofen, and methadone and anesthetized with propofol and isoflurane. Blood pressure, heart rate, and end-tidal isoflurane concentration were measured every minute. The effects of various events during surgery on physiologic variables were analyzed using mixed linear models. Blood and urine samples were collected before anesthesia, before incision, before and after removal of ovaries with a 15 minute pause between ovary removal, and after abdominal closure. Plasma vasopressin and urinary noradrenalin and creatinine concentrations were analyzed. RESULTS: The magnitude of blood pressure increase at removal of the 1st ovary was greater than for the 2nd ovary because of an elevation in baseline. Similarly, the heart rate increased at the removal of the 1st ovary but not at removal of the 2nd ovary. Plasma vasopressin concentration increased at removal of both ovaries. Urinary noradrenalin/creatinine ratio increased at anesthesia, removal of both ovaries, and was elevated at closure of the abdomen. End-tidal isoflurane concentration did not change. Blood pressure and vasopressin concentrations changed in parallel using z-scores for comparison. CONCLUSIONS: Peak values for blood pressure, heart rate, plasma vasopressin concentration, and urinary noradrenalin/creatinine ratio did not differ between removals of the ovaries. Relative changes differed between repeated noxious stimuli, which should be considered in evaluation of methods at ovary removal.

The ABCC4 gene is associated with pyometra in golden retriever dogs.

Pyometra is one of the most common diseases in female dogs, presenting as purulent inflammation and bacterial infection of the uterus. On average 20% of intact female dogs are affected before 10 years of age, a proportion that varies greatly between breeds (3-66%). The clear breed predisposition suggests that genetic risk factors are involved in disease development. To identify genetic risk factors associated with the disease, we performed a genome-wide association study (GWAS) in golden retrievers, a breed with increased risk of developing pyometra (risk ratio: 3.3). We applied a mixed model approach comparing 98 cases, and 96 healthy controls and identified an associated locus on chromosome 22 (p = 1.2 × 10-6, passing Bonferroni corrected significance). This locus contained five significantly associated SNPs positioned within introns of the ATP-binding cassette transporter 4 (ABCC4) gene. This gene encodes a transmembrane transporter that is important for prostaglandin transport. Next generation sequencing and genotyping of cases and controls subsequently identified four missense SNPs within the ABCC4 gene. One missense SNP at chr22:45,893,198 (p.Met787Val) showed complete linkage disequilibrium with the associated GWAS SNPs suggesting a potential role in disease development. Another locus on chromosome 18 overlapping the TESMIN gene, is also potentially implicated in the development of the disease.

Clinical pharmacology of methadone in dogs.

OBJECTIVE: To investigate the pharmacokinetics and effects of methadone on behaviour and plasma concentrations of cortisol and vasopressin in healthy dogs. STUDY DESIGN: Randomized, cross-over, experimental trial. ANIMALS: Nine adult dogs (beagle and beagle cross breeds), four males and five females. METHODS: Methadone hydrochloride, 0.4 mg kg(-1), was administered intravenously (IV) and subcutaneously (SC) with a crossover design. Drug and hormone analyses in plasma were performed using Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry and radioimmunoassay respectively. Behavioural data were collected using a standardized protocol. RESULTS: After IV administration, the plasma concentration of methadone at 10 minutes was 82.1 +/- 9.2 ng mL(-1) (mean +/- SD), the terminal half-life was 3.9 +/- 1.0 hours, the volume of distribution 9.2 +/- 3.3 L kg(-1) and plasma clearance 27.9 +/- 7.6 mL minute(-1) kg(-1). After SC administration, time to maximal plasma concentration was 1.26 +/- 1.04 hours and maximal plasma concentration of methadone was 23.9 +/- 14.4 ng mL(-1), the terminal half-life was 10.7 +/- 4.3 hours and bioavailability was 79 +/- 22%. Concentrations of both cortisol and vasopressin were increased for an hour following IV methadone. The observed behavioural effects of methadone were decreased licking and swallowing and an increase in whining after SC administration. The latter finding is notable as it can be misinterpreted as pain when methadone is used as an analgesic. CONCLUSION AND CLINICAL RELEVANCE: When methadone was administered by the SC route, the half-life was longer, but the individual variation in plasma concentrations was greater compared with IV administration. Increased frequency of whining occurred after administration of methadone and may be a drug effect and not a sign of pain. Cortisol and vasopressin concentrations in plasma may not be suitable for evaluating analgesia after methadone treatment.

Cartilage Health in Knees Treated with Metal Resurfacing Implants or Untreated Focal Cartilage Lesions: A Preclinical Study in Sheep.

BACKGROUND: Full-depth cartilage lesions do not heal and the long-term clinical outcome is uncertain. In the symptomatic middle-aged (35-60 years) patient, treatment with metal implants has been proposed. However, the cartilage health surrounding these implants has not been thoroughly studied. Our objective was to evaluate the health of cartilage opposing and adjacent to metal resurfacing implants. METHODS: The medial femoral condyle was operated in 9 sheep bilaterally. A metallic resurfacing metallic implant was immediately inserted into an artificially created 7.5 mm defect while on the contralateral knee the defect was left untreated. Euthanasia was performed at 6 months. Six animals, of similar age and study duration, from a previous study were used for comparison in the evaluation of cartilage health adjacent to the implant. Cartilage damage to joint surfaces within the knee, cartilage repair of the defect, and cartilage adjacent to the implant was evaluated macroscopically and microscopically. RESULTS: Six animals available for evaluation of cartilage health within the knee showed a varying degree of cartilage damage with no statistical difference between defects treated with implants or left untreated ( P = 0.51; 95% CI -3.7 to 6.5). The cartilage adjacent to the implant (score 0-14; where 14 indicates no damage) remained healthy in these 6 animals showing promising results (averaged 10.5; range 9-11.5, SD 0.95). Cartilage defects did not heal in any case. CONCLUSION: Treatment of a critical size focal lesion with a metal implant is a viable alternative treatment.

Catestatin and vasostatin concentrations in healthy dogs.

BACKGROUND: The neuroendocrine glycoprotein chromogranin A is a useful biomarker in humans for neuroendocrine tumors and stress. Chromogranin A can be measured in both blood and saliva. The objective of this study was to investigate concentrations of and correlation between the chromogranin A epitopes catestatin and vasostatin in healthy dogs accustomed to the sample collection procedures. Blood and saliva samples were collected from 10 research Beagle dogs twice daily for 5 consecutive days, and from 33 privately-owned blood donor dogs in association with 50 different blood donation occasions. All dogs were familiar with sample collection procedures. During each sampling, stress behavior was scored by the same observer using a visual analog scale (VAS) and serum cortisol concentrations. Catestatin and vasostatin were analyzed using radioimmunoassays for dogs. RESULTS: The dogs showed minimal stress behavior during both saliva sampling and blood sampling as monitored by VAS scores and serum cortisol concentrations. Few and insufficient saliva volumes were obtained and therefore only catestatin could be analyzed. Catestatin concentrations differed significantly and did not correlate significantly with vasostatin concentrations (P < 0.0001). Age, gender, breed, and time of sample collection did not significantly affect concentrations of plasma catestatin, vasostatin, and saliva catestatin. CONCLUSIONS: The normal ranges of plasma catestatin (0.53-0.98 nmol/l), vasostatin (0.11-1.30 nmol/l), and saliva catestatin (0.31-1.03 nmol/l) concentrations in healthy dogs accustomed to the sampling procedures were determined. Separate interpretation of the different chromogranin A epitopes from either saliva or plasma is recommended.

Catestatin, vasostatin, cortisol, and pain assessments in dogs suffering from traumatic bone fractures.

BACKGROUND: Traumatic bone fractures cause moderate to severe pain, which needs to be minimized for optimal recovery and animal welfare, illustrating the need for reliable objective pain biomarkers for use in a clinical setting. The objectives of this study were to investigate catestatin (CST) and vasostatin (VS) concentrations as two new potential biomarkers, and cortisol concentrations, scores of the short form of the Glasgow composite measure pain scale (CMPS-SF), and visual analog scale (VAS) in dogs suffering from traumatic bone fractures before and after morphine administration in comparison with healthy dogs. METHODS: Fourteen dogs with hind limb or pelvic fractures and thirty healthy dogs were included. Dogs with fractures were divided into four groups according to analgesia received before participation. Physical examination, CMPS-SF, pain and stress behavior VAS scores were recorded in all dogs. Saliva and blood were collected once in healthy dogs and in dogs with fractures before and 35-70 min after morphine administration. Blood samples were analyzed for CST, VS, and cortisol. Saliva volumes, however, were insufficient for analysis. RESULTS: Catestatin and cortisol concentrations, and CMPS-SF, and VAS scores differed significantly between dogs with fractures prior to morphine administration and healthy dogs. After morphine administration, dogs with fractures had significantly decreased CMPS-SF and VAS scores and, compared to healthy dogs, CST concentrations, CMPS-SF, and VAS scores still differed significantly. However, CST concentrations remained largely within the normal range. Absolute delta values for CST significantly correlated with delta values for CMPS-SF. Catestatin and cortisol did not differ significantly before and after morphine administration. Vasostatin concentrations did not differ significantly between groups. CONCLUSIONS: Catestatin and cortisol concentrations, CMPS-SF, and VAS scores differed significantly in the dogs with traumatic bone fractures compared to the healthy dogs. Morphine treatment partially relieved pain and stress according to the subjective but not according to the objective assessments performed. However, because of the large degree of overlap with normal values, our results suggest that plasma CST concentrations have a limited potential as a clinically useful biomarker for pain-induced stress.

Kinematic and spatiotemporal assessment of habituation to treadmill walking in Labrador retrievers.

BACKGROUND: This study investigated differences in kinematic and spatiotemporal variables in Labrador retrievers during introduction to treadmill walking, with the aim to determine the time required for them to become habituated. Twenty-five healthy, treadmill-naive Labrador retrievers participated in the study. The total angular displacement of the carpus, elbow, tarsus and stifle, as well as stride time and stance duration were calculated from the 3-D tracking of skin mounted reflective markers recorded with 6 infrared light emitting video cameras at 240 Hz. The measurements were done at two walking speeds, 0.78 and 0.96 m/s, in six sessions on the treadmill during two consecutive days. RESULTS: With a 1-2 min acclimatization period following each treadmill speed change, mean values of the study variables were significantly different from the last training session mainly in the first session on the first day. However, between-stride variability was significantly larger for at least one variable even in the fourth session for the slower walking speed, and in the fifth session for the higher walking speed. CONCLUSIONS: The results show the importance of proper pre-training of dogs in locomotion studies at walk using a treadmill, and the need to consider not only variable mean values but also between-stride variability, in order to ensure that dogs are sufficiently accustomed to allow collection of reliable data.

Online dosimetry for temoporfin-mediated interstitial photodynamic therapy using the canine prostate as model.

Online light dosimetry with real-time feedback was applied for temoporfin-mediated interstitial photodynamic therapy (PDT) of dog prostate. The aim was to investigate the performance of online dosimetry by studying the correlation between light dose plans and the tissue response, i.e., extent of induced tissue necrosis and damage to surrounding organs at risk. Light-dose planning software provided dose plans, including light source positions and light doses, based on ultrasound images. A laser instrument provided therapeutic light and dosimetric measurements. The procedure was designed to closely emulate the procedure for whole-prostate PDT in humans with prostate cancer. Nine healthy dogs were subjected to the procedure according to a light-dose escalation plan. About 0.15 mg/kg temoporfin was administered 72 h before the procedure. The results of the procedure were assessed by magnetic resonance imaging, and gross pathology and histopathology of excised tissue. Light dose planning and online dosimetry clearly resulted in more focused effect and less damage to surrounding tissue than interstitial PDT without dosimetry. A light energy dose-response relationship was established where the threshold dose to induce prostate gland necrosis was estimated from 20 to 30 J/cm2.

Catestatin, vasostatin, cortisol, temperature, heart rate, respiratory rate, scores of the short form of the Glasgow composite measure pain scale and visual analog scale for stress and pain behavior in dogs before and after ovariohysterectomy.

BACKGROUND: The stress reaction induced by surgery and associated pain may be detrimental for patient recovery and should be minimized. The neuropeptide chromogranin A (CGA) has shown promise as a sensitive biomarker for stress in humans. Little is known about CGA and its derived peptides, catestatin (CST) and vasostatin (VS), in dogs undergoing surgery. The objectives of this study were to investigate and compare concentrations of CGA epitopes CST and VS, cortisol, body temperature, heart rate, respiratory rate, scores of the short form of the Glasgow composite measure pain scale (CMPS-SF) and visual analog scales (VAS) for stress and pain behavior in dogs before and after ovariohysterectomy. METHODS: Thirty healthy privately owned female dogs admitted for elective ovariohysterectomy were included. Physical examination, CMPS-SF, pain behavior VAS, and stress behavior VAS were recorded and saliva and blood samples were collected before surgery, 3 h after extubation, and once at recall 7-15 days after surgery. Dogs were premedicated with morphine and received carprofen as analgesia for 7 days during the postoperative period. RESULTS: At 3 h after extubation, CMPS-SF and pain behavior VAS scores had increased (p < 0.0001) and stress behavior VAS scores, temperature, respiratory rate (p < 0.0001), plasma CST concentrations (p = 0.002) had decreased significantly compared to before surgery. No significant differences were observed in the subjective and physiological parameters between before surgery and at recall, but plasma CST (p = 0.04) and serum cortisol (p = 0.009) were significantly lower at recall. Plasma VS, saliva CST, and heart rate did not differ significantly at any observed time. CONCLUSION: Study parameters for evaluating surgery-induced stress and pain changed in dogs subjected to ovariohysterectomy. To further evaluate CST and VS usefulness as pain biomarkers, studies on dogs in acute painful situations are warranted.

Animal models for treatment of unresectable liver tumours: a histopathologic and ultra-structural study of cellular toxic changes after electrochemical treatment in rat and dog liver.

INTRODUCTION: Electrochemical treatment (EChT) has been taken under serious consideration as being one of several techniques for local treatment of malignancies. The advantage of EChT is the minimal invasive approach and the absence of serious side effects. Macroscopic, histopathological and ultra-structural findings in liver following a four-electrode configuration (dog) and a two-electrode EChT design (dog and rat) were studied. MATERIALS AND METHODS: 30 female Sprague-Dawley rats and four female beagle dogs were studied with EChT using Platinum:Iridium electrodes and the delivered dose was 5, 10 or 90 C (As). After EChT, the animals were euthanized. RESULTS: The distribution of the lesions was predictable, irrespective of dose and electrode configuration. Destruction volumes were found to fit into a logarithmic curve (dose-response). Histopathological examination confirmed a spherical (rat) and cylindrical/ellipsoidal (dog) lesion. The type of necrosis differed due to electrode polarity. Ultra-structural analysis showed distinct features of cell damage depending on the distance from the electrode. Histopathological and ultra-structural examination demonstrated that the liver tissue close to the border of the lesion displayed a normal morphology. CONCLUSIONS: The in vivo dose-planning model is reliable, even in species with larger tissue mass such as dogs. A multi-electrode EChT-design could obtain predictable lesions. The cellular toxicity following EChT is clearly identified and varies with the distance from the electrode and polarity. The distinct border between the lesion and normal tissue suggests that EChT in a clinical setting for the treatment of liver tumours can give a reliable destruction margin.

Serum thymidine kinase activity in dogs with malignant lymphoma: a potent marker for prognosis and monitoring the disease.

Serum thymidine kinase (sTK) activity was evaluated as a tumor marker for canine malignant lymphoma (ML). The objective was to investigate if sTK, as in humans, could be used as a prognostic marker for survival time in dogs with ML and if sTK could identify early signs of progression of disease in treated dogs. Serum samples from 52 dogs with ML were tested for initial TK activity. Samples from 21 normal dogs and 25 dogs with nonhematologic neoplasms were used for comparison. Forty-four dogs with ML were treated. Serum TK activity was measured in treated dogs before each treatment and every 4 weeks thereafter until relapse. Dogs with ML had 2-180 times higher TK activity (TK 5-900 U/L) than normal dogs (TK <7 U/L) based on the mean + 2 standard deviations. In the group of other neoplasms, only 2 dogs had a moderate increase (6.4 and 7.5 U/L) compared with the controls. Mean sTK activities in the dogs with ML that had gone into complete remission (CR) were not significantly different from activities in healthy controls (P = .68). Mean sTK at least 3 weeks before and at the time of relapse was significantly higher than activity measured at CR (P < .0001). Dogs with ML that initially had sTK >30 U/L had significantly shorter survival times (P < .0001). Furthermore, sTK activity reflected the clinical staging of ML. Measuring sTK can be used as a powerful objective tumor marker for prognosis and for predicting relapse before recurrence of clinically detectable disease in dogs with ML undergoing chemotherapy.

Characterization of the bacterial population of the genital tract of adult cats.

OBJECTIVE: To characterize the bacteria of the genital tract in adult cats; assess the effect of estrus, mating, and administration of progestins on those microorganisms in females; and evaluate whether results of bacteriologic culture of vaginal swabs are affected by cleansing of the vulva prior to sampling or by repeated sampling. ANIMALS: 66 female and 29 male cats undergoing routine ovariohysterectomy or castration. PROCEDURE: Specimens were obtained from vaginal and uterine or preputial mucosae with swabs moistened with sterile saline (0.9% NaCl) solution. In 9 cats, vaginal specimens were obtained before and after cleansing of the vulva with ethanol; in 7 female cats, 2 vaginal speci mens were obtained in immediate succession. RESULTS: Aerobic bacteria were most commonly isolated from cats' vaginas and prepuces; anaerobic bacteria were isolated frequently from males (41%) but rarely from females (5%). Generally, culture results were not affected by cleansing of the vulva or repeated vaginal sampling. The bacterial population of the vaginas of cats was influenced by stage of the estrous cycle but not by mating or administration of progestins. Bacteria were not isolated from the uterus of any cat. CONCLUSIONS AND CLINICAL RELEVANCE: In cats, bacteria of the genital tract in females are predominantly aerobic; in males, aerobic and anaerobic bacteria are found. The bacterial population of the vagina is affected by stage of the estrous cycle. Pure growth of bacteria in culture of genital tract specimens is a normal finding; antimicrobials should only be administered if clinical signs of genital infection are present.

C-reactive protein in the differentiation of pyometra from cystic endometrial hyperplasia/mucometra in dogs.

Hematological parameters, plasma C-reactive protein (CRP), and tumor necrosis factor alpha were analyzed in 64 dogs with a presumptive diagnosis of pyometra. Final diagnosis (i.e., pyometra or cystic endometrial hyperplasia [CEH]) was determined by histopathology. As a single test, the percentage of band neutrophils had the highest sensitivity in the prediction of pyometra (sensitivity, 94%). The combination of percentage of bands and CRP had the highest sensitivity (97.7%; specificity, 75%) in predicting the presence of pyometra. The most common clinical signs noted in the study were vaginal discharge, polyuria, polydipsia, lethargy, and gastrointestinal signs. A combination of three or more of these clinical signs was significantly associated with pyometra.

Ligation of the spermatic cord in dogs with a self-locking device of a resorbable polyglycolic based co-polymer--feasibility and long-term follow-up study.

BACKGROUND: New surgical techniques are developed to enable a quicker, easier and safer surgery with reduced risk of complications and shortened time needed for recovery. A resorbable device, a self-locking loop, was designed for surgical ligation. The objective of this pilot study was to investigate the feasibility of ligating the spermatic cord with the device, its biocompatibility and long-term resorption in dogs. RESULTS: The device was made of a block co-polymer (glycolide and trimethylene carbonate), manufactured by injection moulding and consisted of a flexible band running through a case with a locking mechanism. Ten devices were tested for ligation of the spermatic cords in five dogs admitted for routine neutering. The dogs were monitored by physical examination and ultrasonography of the site of ligation, area of spermatic cord and medial iliac lymph nodes regularly until no hyperechoic remnants of the device or acoustic shadowing or local tissue reactions were observed. Haemostasis of the spermatic cords was achieved with the devices. On ultrasonography the devices were seen as hyperechoic structures for 2 months after neutering causing acoustic shadowing for 1 month. The dogs were monitored for 3 - 5 months after surgery. Gradual decrease in echogenicity and final disappearance of the hyperechoic structures suggested resorption. Macroscopic and histological post mortem examinations were performed in one dog at 3 months after surgery. Post mortem examination showed a tissue reaction of a suture granuloma that was restricted in extent at site of the device. CONCLUSIONS: The results of this pilot study suggest biocompatibility and indicate that ligation of the spermatic cord is feasible with the device.

Ligation of the ovarian pedicles in dogs with a resorbable self-locking device--a long-term follow-up study.

A prospective clinical trial was performed to evaluate applicability, hemostatic efficiency, and long-term tissue reactions of a novel medical device. The device was made of polydioxanone and designed in principle as a cable-tie with a flexible band running through a locking case. It was tested for ligation of the ovarian pedicles during ovariohysterectomy in nine intact female dogs. The dogs were followed-up monthly by physical examination and ultrasonography of the abdomen for 5-12 months after surgery. Macroscopic and histological post mortem examinations were performed in two dogs 7 and 18 months after surgery. Hemostasis was achieved with the devices although 1 of the 18 devices needed further tightening during a reoperation. Ultrasonography revealed a hyperechoic device that caused acoustic shadowing, which decreased over time indicating gradual resorption. Post mortem examinations demonstrated adhesions and a local transient tissue reaction at site of the device. The results show that the device may be a future alternative for ligation of ovarian pedicles in dogs.

Intervertebral disc degeneration in the dog. Part 2: chondrodystrophic and non-chondrodystrophic breeds.

Dogs can be grouped into two distinct types of breed based on the predisposition to chondrodystrophy, namely, non-chondrodystrophic (NCD) and chondrodystrophic (CD). In addition to a different process of endochondral ossification, NCD and CD breeds have different characteristics of intravertebral disc (IVD) degeneration and IVD degenerative diseases. The anatomy, physiology, histopathology, and biochemical and biomechanical characteristics of the healthy and degenerated IVD are discussed in the first part of this two-part review. This second part describes the similarities and differences in the histopathological and biochemical characteristics of IVD degeneration in CD and NCD canine breeds and discusses relevant aetiological factors of IVD degeneration.

Intervertebral disc degeneration in the dog. Part 1: Anatomy and physiology of the intervertebral disc and characteristics of intervertebral disc degeneration.

Intervertebral disc (IVD) degeneration is common in dogs and can give rise to a number of diseases, such as IVD herniation, cervical spondylomyelopathy, and degenerative lumbosacral stenosis. Although there have been many reports and reviews on the clinical aspects of canine IVD disease, few reports have discussed and reviewed the process of IVD degeneration. In this first part of a two-part review, the anatomy, physiology, histopathology, and biochemical and biomechanical characteristics of the healthy and degenerated IVD are described. In Part 2, the aspects of IVD degeneration in chondrodystrophic and non-chondrodystrophic dog breeds are discussed in depth.

Incidence of intervertebral disk degeneration-related diseases and associated mortality rates in dogs.

OBJECTIVE: To determine the incidence and distribution of intervertebral disk (IVD) degeneration-related diseases in a large population of dogs of various breeds, ages, and sexes and to determine mortality rates among dogs with these diseases. DESIGN: Epidemiological study. SAMPLE: Insurance data for dogs with veterinary health-care and life insurance coverage (n = 665,249 and 552,120, respectively). PROCEDURES: Insurance claim records of 1 company in Sweden were searched to identify dogs with IVD degeneration-related diseases; incidence and mortality rates were determined for affected dogs < 12 years old and < 10 years old, respectively. Only the first paid IVD degeneration-related claim for a dog was included in incidence rate calculations. RESULTS: The incidence rate of IVD degeneration-related diseases was 27.8 (95% confidence interval [CI], 27.2 to 28.4) occurrences/10,000 dog-years at risk (DYAR), indicating that approximately 0.3% of dogs/y in this population were affected. Miniature Dachshund was the most highly represented breed, followed by Standard Dachshund and Doberman Pinscher (237.1 [95% CI, 212.9 to 261.4], 141.5 [95% CI, 135.5 to 147.4], and 88.6 [95% CI, 72.1 to 105.2] occurrences/10,000 DYAR, respectively). The incidence rate of IVD degeneration-related disease was greater in male than in female dogs and increased with age. Overall mortality rate attributed to IVD degeneration-related diseases was 9.4 (95% CI, 8.9 to 9.8) deaths/10,000 DYAR and was greater in males than in females. CONCLUSIONS AND CLINICAL RELEVANCE: Differences in incidence rates among various breeds suggested a genetic involvement. Knowledge of the distribution of IVD degeneration-related diseases among dogs of various breeds and ages may facilitate early diagnosis and preemptive treatments in patients at risk for developing these diseases.

The dog as an animal model for intervertebral disc degeneration?

STUDY DESIGN: Prospective observational and analytic study. OBJECTIVE: To investigate whether spontaneous intervertebral disc degeneration (IVDD) occurring in both chondrodystrophic (CD) and nonchondrodystrophic dogs (NCD) can be used as a valid translational model for human IVDD research. SUMMARY OF BACKGROUND DATA: Different animal models are used in IVDD research, but in most of these models IVDD is induced manually or chemically rather than occurring spontaneously. METHODS: A total of 184 intervertebral discs (IVDs) from 19 dogs of different breeds were used. The extent of IVDD was evaluated by macroscopic grading, histopathology, glycosaminoglycan content, and matrix metalloproteinase 2 activity. Canine data were compared with human IVD data acquired in this study or from the literature. RESULTS: Gross pathology of IVDD in both dog types (CD and NCD) and humans showed many similarities, but the cartilaginous endplates were significantly thicker and the subchondral cortices significantly thinner in humans than in dogs. Notochordal cells were still present in the IVDs of adult NCD but were not seen in the CD breeds or in humans. Signs of degeneration were seen in young dogs of CD breeds (<1 year of age), whereas this was only seen in older dogs of NCD breeds (5-7 years of age). The relative glycosaminoglycan content and metalloproteinase 2 activity in canine IVDD were similar to those in humans: metalloproteinase 2 activity increased and glycosaminoglycan content decreased with increasing severity of IVDD. CONCLUSION: IVDD is similar in humans and dogs. Both CD and NCD breeds may therefore serve as models of spontaneous IVDD for human research. However, as with all animal models, it is important to recognize interspecies differences and, indeed, the intraspecies differences between CD and NCD breeds (early vs. late onset of IVDD, respectively) to develop an optimal canine model of human IVDD.

A breed-matched case-control study of potential risk-factors for canine pyometra.

The objective was to evaluate plausible risk-factors for pyometra, a common disease affecting almost 25% of all (unspayed) female dogs before 10 years of age. Because of the strong breed-predilection, an age- and breed-matched case-control study was undertaken on 87 pairs (pyometra-cases and healthy controls) from five breeds (Rottweiler (n = 13), Collie (n = 8), Golden retriever (n = 24), Labrador retriever (n = 16) and German shepherd dog (n = 26)). The mean age was 7.9 y (range 0.8-13.8 y). Variables analyzed included pseudopregnancy, age at first oestrus, length of and regularity of the interoestrus interval, hormone treatments, nulliparity, number of parities, age at first whelping, previous urinary tract infections and mammary tumours. Data were modelled multivariably using matched-pair conditional logistic regression. Analysing interactions with breed, previous pregnancy was statistically associated with pyometra. When amalgamated, in three breeds previous pregnancy was protective (Rottweiler, Collie, Labrador retriever) and in one breed statistically intermediate (German shepherd dog) when compared to the baseline (Golden retriever). Previous pregnancy was a statistically significant factor that had a protective effect against pyometra in some breeds but not in the Golden retriever breed. These findings indicate that protective- and risk-factors may vary between different breeds. The obvious problem with low power and limited possibility for extrapolation, using few dogs in few breeds, is acknowledged. However, it is suggested that failure to control for the confounding effect of breed, especially in epidemiological studies on dog diseases, may lead to potentially erroneous conclusions.