Using the canine genome to cure cancer and other diseases.

A high-quality draft genome sequence of the domestic dog (Canis familiaris), together with a dense map of single nucleotide polymorphisms, has been reported. Such new tools offer scientists amazing opportunities to define genetic, nutritional, environmental, and other risk factors for various canine diseases. Because many of the diseases that affect man's best friend also affect us, understanding a dog's disease may lead to new preventions and therapies for diseases that affect both dogs and people. Since a dog's life span is shorter than that for a human, monitoring potential risk factors in a well-controlled population of dogs is possible. Such a population should be one where dogs live in close relationship with their owners. Although longitudinal studies have been previously conducted on animals housed in laboratory environments, the natural environment offers a chance to study dogs in environments shared by their owners. If dogs are carefully monitored, and select exposures defined, considerable information could be collected in a dog's lifetime--the next 10-20 years. Such information could hold the clues for important discoveries, including causes and cures for cancer.

Using genetic technologies for promoting canine health and temperament.

The entire canine genome is scheduled to be sequenced by researchers at the Whitehead Institute/MIH Center for Genome Research by the end of 2004. Thus, new genetic technologies are likely to be developed that can soon predict certain aspects of health and temperament in dogs. The C. familiaris is similar in size to that of humans and other mammals, with an estimated 2.8 billion base pairs. Although, the boxer was chosen as the first breed to sequence, it will have application for all dog breeds. Once the entire genome is sequenced, genetic markers for specific diseases and temperaments may be developed, which can guide breeders to make informed decisions concerning breeding management. Such a technology may be useful for guide and service dog organizations that have breeding colonies. It is important that the human-animal bond be preserved for as long as possible, both for pet owners and also for those disabled individuals who depend upon a dog for independence and mobility. Because genetic diseases may not manifest in carriers, and some genetic diseases do not manifest until after a dog is older and has already produced other animals with the same defect, genetic markers to identify some of the over 400 genetic diseases could be very useful in promoting canine health.

Early-age neutering of dogs and cats in the United States (a review).

Prepubertal gonadectomy, often referred to as early-age neutering, has increased in popularity in the United States. The procedure is often used at animal care and control facilities, where puppies and kittens are neutered as early as 7 weeks of age or before adoption. Although the anaesthetic and surgical procedures appear to be safe, studies continue to evaluate the long-term effects on health and behaviour. Early-age neutering is one technique that is used to combat pet overpopulation, a problem whereby millions of unwanted healthy dogs and cats are euthanased each year. Although neutering animals is helpful in controlling pet overpopulation, other factors must be considered. In addition, many animals are relinquished to shelters when they show inappropriate behaviours, because owners and veterinarians are unable to modify animal behaviour. This review discusses early-age neutering in the United States, and includes the review of scientific studies that have evaluated this procedure in puppies and kittens. Early-age neutering does not stunt growth in dogs or cats (a once-held belief), but may alter metabolic rates in cats. The anaesthetic and surgical procedures are apparently safe for young puppies and kittens; morbidity is lower and recovery is faster than in adult animals. To date, adverse side effects are apparently no greater in animals neutered at early ages (7 weeks) than in those neutered at the conventional age (7 months).

The effects of stains and investigators on assessment of morphology of canine spermatozoa.

Percentage and types of morphological abnormalities found in canine spermatozoa were evaluated by three investigators using three stains (Giemsa-Wright stain [Diff-Quik], eosin Y/nigrosin [Hancock], and eosin B/nigrosin [Society for Theriogenology morphology stain] with conventional light microscopy, compared to phase contrast microscopy on unstained samples. The percentage of spermatozoa with abnormal heads, midpieces, and tails varied by technique and by investigator. Average percentages of morphologically normal spermatozoa were significantly higher in samples stained with Diff-Quik and samples examined by phase contrast microscopy than in samples stained with Hancock or Society for Theriogenology morphology stains. No effect of investigator on the percentage of morphologically normal spermatozoa was assessed. Results suggest that staining or preparation technique may alter the morphology of canine spermatozoa artifactually.

The prevalence of diffuse idiopathic skeletal hyperostosis (DISH) in two large American Midwest metropolitan hospital populations.

OBJECTIVE: There are no published large-scale studies of the overall prevalence of diffuse idiopathic skeletal hyperostosis (DISH) and it has been proposed that the prevalence is greater than previously reported. We thus decided to review chest radiographs in a population of patients over 50 years of age seen at two large but differing metropolitan hospitals in a major American Mid-west city. DESIGN AND PATIENTS: The posterior-anterior and lateral chest radiographs of 1363 patients were reviewed for evidence of DISH at the University of Minnesota Hospital and Clinic. There were 500 consecutive inpatient admissions, 540 consecutive patients who attended the outpatient clinics and 326 patients collected from our film archive. A population of 1001 patients seen at Hennepin County Medical Center was also studied. It was possible to subclassify this latter group with respect to race. RESULTS AND CONCLUSION: Using strict criteria, i.e., four or more levels involved, the overall prevalence of DISH in the male population over age 50 years was 25% and in the female population over age 50 years was 15%. This prevalence climbed to 28% in males over 80 years and to over 35% in males over age 70 years. In females over 80 years, the prevalence was found to be 26%. Although our population base was small, DISH was found to be less common in the black, Native-American and Asian populations. The prevalence of DISH was also found to be far lower in a similar white population with osteoporosis. The overall prevalence of DISH was higher than expected in a predominantly white population over age 50 years with a lesser incidence in the black, Native-American and Asian populations, suggesting a genetic origin of the condition.

Use of MRI in evaluating postoperative changes in patients with bone and soft tissue tumors.

We reviewed the clinical, surgical and magnetic resonance imaging (MRI) findings in 80 patients who underwent resection of primary benign or malignant bone or soft tissue tumors. There were 18 benign and 62 malignant tumors. Although 31 patients were originally thought to have recurrence, on review only 20 patients were considered to have recurred. Of these, three were found only to have postoperative changes at surgery. Seventeen patients actually had recurrence of tumor. We believe that the presence of an actual mass lesion on MRI is the cornerstone for the correct diagnosis of recurrent tumor.

The effect of prepuberal and postpuberal gonadectomy on radial physeal closure in male and female domestic cats.

Male (n = 6/group) and female (n = 6/group) kittens were gonadectomized at 7 weeks (prepuberally) or 7 months of age (postpuberally), or left intact. Lateral radiographic projections of the right forelimb were made from 4 months of age until the distal radial physis was closed, or 24 months of age. In males, distal radial physeal closure was delayed in both groups of gonadectomized animals, compared to intact males (p < 0.01). In females, proximal radial physeal closure was significantly delayed in prepuberally gonadectomized animals (p = 0.02), and distal radial physeal closure was significantly delayed in both groups of gonadectomized animals, compared to intact animals (p < 0.01). Final radial length (females p < 0.01, males p = 0.01), and age and radial length at time of the growth plateau (p < 0.01) were significantly increased in all gonadectomized animals. Age at gonadectomy had no effect on age and radial length at time of the growth plateau. No puberal growth spurt was observed in any of the cats.

"Incisura" of the ascending aorta and vascular pedicle width in the cardiac transplant patient.

BACKGROUND: The purpose of this study was to evaluate three findings in cardiac transplant patients: the appearance, etiology, and incidence of "incisura" (a characteristic indentation) of the ascending aorta; the vascular pedicle width, which usually appears enlarged on standard chest radiographs; and clearing of the retrosternal clear space. MATERIAL: Two hundred sixty-one cardiac transplantations were performed at the University of Minnesota before December 31, 1992. The appearance, etiology, and incidence of an incisura were studied; the vascular pedicle width was measured; and the rate of clearing of the retrosternal clear space was determined. RESULTS: Forty-six percent of the patients whose ascending aorta could be visualized on the lateral chest radiogram showed an incisura. Approximately one third of the patients showed continued opacification of the retrosternal space postoperatively. The width of the vascular pedicle in this series of cardiac transplant patients measured 60.9 +/- 22.8 mm (standard deviation, 11.4 mm), in comparison to a normal of 48 +/- 5.0 mm. CONCLUSIONS: An incisura of the ascending aorta and the widened vascular pedicle are normal postoperative chest radiographic findings in cardiac transplant patients and should not be misconstrued as abnormalities.

Effect of prepuberal and postpuberal gonadectomy on heat production measured by indirect calorimetry in male and female domestic cats.

OBJECTIVE: To use indirect calorimetry to compare heat production between gonadectomized and sexually intact male and female cats. DESIGN: Male (n = 6) and female (n = 6) kittens were gonadectomized at 7 weeks or 7 months of age, or left sexually intact. Body heat production was measured by indirect calorimetry in all cats at 12, 18, and 24 months of age. ANIMALS: 18 male and 18 female clinically normal domestic shorthair cats. PROCEDURE: Heat production was measured, using an open-circuit, respiratory, indirect calorimeter. All cats underwent calorimetry at 12, 18, and 24 months of age. The heat coefficient, a measure of resting metabolic rate, was calculated for each cat at each test; heat coefficient is defined as logarithm of heat (kcal/h) divided by logarithm of body weight (kg). RESULTS: Heat production did not vary with age in male or female cats. Heat coefficient was higher in sexually intact male and female cats than in gonadectomized male and female cats at 12, 18, and 24 months of age (12 months, females, P < 0.01, males, P = 0.04; 18 months, females, P < 0.01, males, P = 0.02; and 24 months, females and males, P < 0.01). CONCLUSIONS: These data suggest that resting metabolic rate in cats decreases after gonadectomy. CLINICAL RELEVANCE: A decrease in metabolic rate is synonymous with a decrease in caloric requirements. Gonadectomized animals fed in a manner similar to sexually intact animals may be predisposed to obesity and its sequelae.

Cyclops lesion.

Postoperative impingement of the knee following ACL reconstruction does occur. MRI can be useful in the diagnosis of the patient who is not recovering as quickly as expected following surgical reconstruction. MRI allows the assessment of 1) tunnel position and alignment, 2) graft integrity, 3) the menisci for possible re-tear or extension of previous tears, and 4) joint for scar tissue and cartilaginous bodies either loose or fixed.

Estrous length, pregnancy rate, gestation and parturition lengths, litter size, and juvenile mortality in the domestic cat.

Reproductive performance in a feline research colony of 14 queens is reported. Average estrous length in 38 cycles was 5.8 +/- 3.3 days, with a range of two to 19 days. Estrous length in 23 bred cycles was not shorter (p greater than 0.05) than in 15 nonbred cycles, suggesting that induction of ovulation does not decrease estrous length. Pregnancy rate in 23 bred cycles was 73.9%. Gestation length averaged 66.9 +/- 2.9 days with a range of 62 to 71 days (n = 15). Average parturition length was 16.1 +/- 14.3 hours (n = 7), with a range of four to 42 hours. Litter size ranged from one to five kittens, with an average of 3.7 kittens per litter (n = 15). Percent mortality by eight weeks of age was 29.1%, with 4.7% stillbirths.

Hyperextension strain or "whiplash" injuries to the cervical spine.

PURPOSE: To define "whiplash" radiologically. MATERIAL AND METHODS: A full cervical spine radiographic series (including flexion and extension views) was reviewed in 40 patients with clinically proven "whiplash" injuries and compared to the radiographs in 105 normal controls. The level and degree of kinking or kyphosis, subluxation, and the difference in the amount of fanning between spinous processes on flexion and extension films were measured in each patient. RESULTS: Localized kinking greater than 10 degrees and over 12 mm of fanning, often occurring at the level below the kinking or kyphosis, occurred mainly in the group of whiplash patients (sensitivity 81%, specificity 76%, accuracy 80%). CONCLUSIONS: Localized kinking greater than 10 degrees and fanning greater than 12 mm are useful measurements by which to separate patients with true whiplash injuries from those with minor ligamentous tears. Flexion and extension views are essential to help define whiplash and other ligamentous injuries of the cervical spine.

Diagnosis of breast implant rupture: imaging findings and relative efficacies of imaging techniques.

OBJECTIVE: The purpose of this study was to compare the efficacies of mammography, sonography, CT, and MR imaging in the detection of breast implant rupture and to analyze the imaging findings. SUBJECTS AND METHODS: Thirty-two women with 63 silicone breast implants participated in the study. All but one had signs and symptoms suggestive of rupture, and all had requested that their implants be removed before they were enrolled in this imaging study. All patients had film-screen mammography, sonography, CT, and MR imaging. Twenty-two ruptures were found at surgery; 21 were intracapsular and one was extracapsular. The relative efficacies of the imaging studies were determined, and the imaging findings were compared with the surgical results. RESULTS: Of the 32 women with 63 implants, mammographic sensitivity for detecting implant rupture was only 23% but the specificity was 98%. Sonography had a higher sensitivity (59%), but its specificity was significantly lower (79%). CT had a sensitivity of 82% and a specificity of 88%. MR was the only imaging technique that consistently provided evidence that enabled the evaluation of intracapsular and extracapsular ruptures. The sensitivity and specificity of MR imaging were 95% and 93%, respectively. CONCLUSION: Our results show that MR imaging is more sensitive and specific for the detection of breast implant rupture than is mammography, CT, or sonography.

Concurrent retrograde ejaculation and hypothyroidism in a dog: case report.

Retrograde ejaculation and hypothyroidism were diagnosed in a 19-mo-old Labrador retriever. The retrograde ejaculation was reversed following the administration of the sympathomimetic agent, pseudoephedrine hydrochloride, at a dose of 4 mg/kg per os given 1 and 3 h before semen collection. Antegrade ejaculation failed to occur after normalization of serum thyroid hormone levels by thyroxine supplementation. The pathophysiology of retrograde ejaculation is reviewed.