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.

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, 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Evaluation of intervertebral disk degeneration in chondrodystrophic and nonchondrodystrophic dogs by use of Pfirrmann grading of images obtained with low-field magnetic resonance imaging.

OBJECTIVE: To assess whether the Pfirrmann system for grading lumbar intervertebral disk (IVD) degeneration in humans can also be used in dogs. ANIMALS: 202 dogs. PROCEDURES: Magnetic resonance imaging was used to obtain images of vertebral segments from dogs, which were reviewed separately by 3 observers who graded the extent of degeneration in each visible IVD by use of the Pfirrmann classification system used for grading lumbar IVD degeneration in humans. Grading was validated against 2 factors associated with the extent of disk degeneration: type of dog (chondrodystrophic or nonchondrodystrophic breeds) and age. RESULTS: Interobserver and intraobserver agreement for Pfirrmann grading of IVD degeneration were good (κ scores, 0.81 to 0.93). An increase in the extent of disk degeneration was positively correlated with increases in age and with chondrodystrophic breed. CONCLUSIONS AND CLINICAL RELEVANCE: The Pfirrmann system was reliably used to grade IVD degeneration in dogs of various breeds and ages. An increase in the extent of IVD degeneration was positively correlated with increases in age and with chondrodystrophic-type dogs.

Reliability of macroscopic grading of intervertebral disk degeneration in dogs by use of the Thompson system and comparison with low-field magnetic resonance imaging findings.

OBJECTIVE: To evaluate the reliability of the Thompson system for use in grading the gross pathological changes of intervertebral disk (IVD) degeneration in dogs and to investigate the agreement between gross pathological findings and low-field (0.2-T) magnetic resonance imaging (MRI) findings. SAMPLE: Vertebral columns from cadavers of 19 dogs of various ages, breeds, and origins. PROCEDURES: 182 intervertebral segments were collected from 19 canine cadavers. Sagittal T2-weighted MRI of the T11 through S1 portion of the vertebral column was performed within 24 hours after the dogs were euthanized. The vertebral columns were subsequently divided in the midsagittal plane, and high-resolution photographs were obtained of each intervertebral segment (end plate-disk-end plate). The MRI images and photographs were graded separately in a blinded manner by 4 observers who used both Pfirrmann and Thompson grading criteria. RESULTS: The interobserver agreement for Thompson scores ranged from 0.76 to 0.88, and the intraobserver agreement ranged from 0.88 to 0.94 (Cohen weighted κ analysis). Agreement between scores for the Pfirrmann and Thompson grading criteria was κ = 0.70. CONCLUSIONS AND CLINICAL RELEVANCE: Grading of IVD degeneration in dogs by use of the Thompson system resulted in high interobserver and intraobserver agreement, and scores for the Thompson system had substantial agreement with low-field MRI findings graded by use of the Pfirrmann system. This suggested that low-field MRI can be used to diagnose IVD degeneration in dogs.

A new resorbable device for ligation of blood vessels - A pilot study.

BACKGROUND: During surgery, controlled haemostasis to prevent blood loss is vital for a successful outcome. It can be difficult to ligate vessels located deep in the abdomen. A device that is easy to use and enables secure ligatures could be beneficial. Cable ties made of nylon have been used for ligation but the non-resorbable material caused tissue reactions. The objective of this study was to use a resorbable material to construct a device with a self-locking mechanism and to test its mechanical strength and ligation efficiency. METHODS: The device was manufactured by injection moulding of polydioxanone, a resorbable polymer used for suture materials. Polydioxanone with inherent viscosities of 1.9 dL/g and 1.3 dL/g were tested. The device consisted of a perforated flexible band which could be pulled through a case with a locking mechanism. After a first version of the device had been tested, some improvements were made. The locking case was downsized, corners were rounded off, the band was made thicker and the mould was redesigned to produce longer devices. Tensile tests were performed with the second version.The first version of the device was used to ligate the ovarian pedicle in a euthanized dog and to test echogenicity of the device with ultrasound. Compression of vessels of the ovarian pedicle was examined by histology. Both versions of the device were tested for haemostasis of and tissue grip on renal arteries in six anaesthetised pigs. RESULTS: The tensile strength of the flexible band of the devices with inherent viscosity of 1.9 dL/g was 50.1 ± 5.5 N (range 35.2-62.9 N, n = 11) and the devices with inherent viscosity of 1.3 dL/g had a tensile strength of 39.8 ± 8.1 N (range 18.6-54.2 N, n = 11). Injection moulding of the polymer with lower inherent viscosity resulted in a longer flow distance.Both versions of the device had an effective tissue grip and complete haemostasis of renal arteries was verified. The device attached to the ovarian pedicle could be seen with ultrasound, and vessel compression and occlusion were verified by histology. CONCLUSIONS: Tests of functionality of the device showed complete haemostasis and good tissue grip. Devices with a band of sufficient length were easily applied and tightened in tissue.

Shedding of chlamydiae in relation to titers of serum chlamydiae-specific antibodies and serum concentrations of two acute-phase proteins in cats without conjunctivitis.

OBJECTIVE: To investigate shedding of chlamydiae from conjunctiva and genital tracts of cats without clinical signs of conjunctivitis or other infectious disease in relation to their titers of serum antibodies against chlamydiae and to serum amyloid A (SAA) and serum α(1)-acid glycoprotein (AGP) concentrations. ANIMALS: 62 healthy cats. PROCEDURES: Serum from each cat was analyzed for antibodies against chlamydiae and for SAA and AGP concentrations. Swab samples from the conjunctival sac and genital tract were analyzed with a real-time PCR assay for Chlamydiaceae. RESULTS: 4 of 8 of cats with high antibody titers (ie, 1,600) shed chlamydiae, but only from the conjunctiva. Chlamydiae could not be detected in samples from cats with lower antibody titers nor from any genital tract samples. In cats with antibody titers of 1,600, mean ± SD SAA concentration was significantly higher when chlamydiae were detected in conjunctival swab samples (3.9 ± 1.0 mg/L) than when no chlamydiae were detected (1.4 ± 1.0 mg/L). However, SAA concentration was greater than the limit for an acute-phase response in only one of those cats. There was no significant difference in serum AGP concentrations between cats with high titers that were or were not shedding chlamydiae. Nine of 30 (30%) cats (5 with and 4 without detectable serum antibodies against chlamydiae) that had been mated developed reproductive disorders. CONCLUSIONS AND CLINICAL RELEVANCE: Clinically normal cats with high chlamydiae-specific antibody titers can shed and thus transmit chlamydiae. Venereal spread from cats without clinical signs of infection is likely not common.

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.

The performance of a hydrogel nucleus pulposus prosthesis in an ex vivo canine model.

A nucleus pulposus prosthesis (NPP) made of the hydrogel N-vinyl-2-pyrrolidinone copolymerized with 2-(4'-iodobenzoyl)-oxo-ethyl methacrylate has recently been developed. The special features of this NPP, i.e. intrinsic radiopacity and its ability to swell in situ to fill the nucleus cavity and restore disc height, were investigated ex vivo in canine spinal specimens. L7-S1 intervertebral discs were isolated from three canine spinal specimens, and the dimensions of the nuclei pulposi were measured. Based on these averaged measurements, the NPP prototype was made and inserted in its dry form (xerogel) into a canine cadaveric spinal segment and allowed to swell overnight at 38 degrees C. The integrity of the NPP and the filling of the nucleus cavity were assessed before and after swelling, using radiography, computed tomography, and magnetic resonance imaging. The ability of the NPP to restore disc height was assessed on radiographs of 10 spinal specimens. Thereafter the NPP was macroscopically assessed in situ by dissection of the spinal specimen. Both on imaging and macroscopically, 9/10 NPPs appeared to have a near perfect fit and disc height was restored in 8/10 spinal segments. The NPP may thus be an acceptable treatment option for low back patients meeting the requirements for NPP treatment.