Hypertrophic osteodystrophy in the Weimaraner dog: lack of association between DQA1 alleles of the canine MHC and hypertrophic osteodystrophy

Hypertrophic osteodystrophy (HOD) is a canine bone disease that affects mainly large breed dogs, including the Weimaraner, and studies have shown a link between recent vaccination with a modified live virus and the onset of HOD in this breed. In humans, it has been suggested that human leukocyte antigen (HLA) alleles can influence antibody response to vaccination. The aim of this study was to investigate whether there is an association between the development of HOD in Weimaraners and MHC alleles at the DLA-DQA1 locus in a group of 33 unrelated dogs. The DQA1 allele and genotype frequencies were determined by sequence-based typing. Although clinical signs developed within six weeks of vaccination in all 12 dogs for which information was available, no association was found between DQA1 alleles and HOD in this population of Weimaraner dogs. A role for other immune-response genes in the pathogenesis of HOD should not however be ruled out. Whereas recent vaccination may be a trigger for the disease, it was concluded that there is no specific vaccine that is most responsible for the expression of the disease.     

Allelic polymorphism in the ovine DQA1 gene

Variation in the ovine DQA1 gene was investigated by amplification of exon 2 using PCR, followed by single-strand conformational polymorphism (SSCP) analysis, cloning, and DNA sequencing. Fourteen novel SSCP patterns, representing 14 different sequences, were identified. Eight of these 14 sequences were identical to published DQA1 sequences from sheep, whereas the remaining six were novel but similar to the published DQA1 sequences from sheep and cattle. These six new sequences exhibited conserved region and variable region patterns similar to the published sheep DQA1 sequences, but were different than the published DQA2 sequences from sheep. All of these 14 putative sheep DQA1 sequences fulfilled the criteria used by the established bovine leukocyte antigens major histocompatibility complex nomenclature committee for assignment as new alleles. Comparison of the available DQA1 sequences from sheep and cattle revealed several clusters of ovine DQA1 sequences, and some sheep alleles were more similar to cattle alleles than other sheep alleles. The occurrence of trans-species polymorphism suggests the action of balancing selection at the DQA1 locus. Twenty-four percent of the nucleotide positions showed variation within exon 2, and this variation seems to have arisen largely by point mutation and gene conversion. The nonsynonymous and synonymous substitution rates were similar in both the putative antigen-binding site codons and the putative nonantigen-binding site codons. The extensive polymorphism reported in this article is consistent with polymorphism reported at the bovine DQA1 locus.     

Clinical electroretinography in the dog. Part 1

In the first of three parts of this investigation the clinical importance and the principal indications for electroretinography are presented. The histology and ultrastructure of the retina with special emphasis on the photoreceptors and the second order neurons are discussed. A section is devoted to the history of electroretinography in man and animals. The components of the ERG and their origin are discussed.     

Polymorphisms in the canine glutamate transporter-1 gene: identification and variation among five dog breeds

Excitatory amino acid transporters (EAATs) are important for terminating glutamatergic neurotransmission and protect central nervous system (CNS) neurons from glutamatergic excitotoxicity. We selected these genes as targets that may relate to canine behavioral traits. After screening four EAAT genes (glutamate transporter-1; GLT-1, excitatory amino acid transporter 4; EAAT4, excitatory amino acid carrier; EAAC1, glutamate/aspartate transporter; GLAST) for single nucleotide polymorphisms (SNPs), we identified two silent SNPs (C129T and T471C) in the GLT-1 gene. We genotyped 193 dogs of 5 breeds and found significant variation among breeds in these two SNPs in GLT-1. The C129T polymorphism was not observed in Malteses and Miniature Schnauzers. These results suggest that polymorphisms in the GLT-1 gene may be useful markers for examining how the genetic background relates to the behavioral traits of dogs.     

Restricted dog leucocyte antigen (DLA) class II haplotypes and genotypes in Beagles

Beagles are commonly used in vaccine trials as part of the regulatory approval process. Genetic restriction within this breed and the impact this might have on vaccine responses are rarely considered. This study was designed to characterise diversity of dog leucocyte antigen (DLA) class II genes in a breeding colony of laboratory Beagles, whose offspring are used in vaccine studies. DLA haplotypes were determined by PCR and sequence-based typing from genomic DNA extracted from blood. Breeding colony Beagles had significantly different DLA haplotype frequencies in comparison with pet Beagles and both groups showed limited DLA diversity. Restricted DLA class II genetic variability within Beagles might result in selective antigen presentation and vaccine responses that are not necessarily representative of those seen in other dog breeds.     

Missense polymorphisms in the MC1R gene of the dog,red fox,arctic fox and Chinese raccoon dog

Coat colour variation is determined by many genes, one of which is the melanocortin receptor type 1 (MC1R) gene. In this study, we examined the whole coding sequence of this gene in four species belonging to the Canidae family (dog, red fox, arctic fox and Chinese raccoon dog). Although the comparative analysis of the obtained nucleotide sequences revealed a high conservation, which varied between 97.9 and 99.1%, we altogether identified 22 SNPs (10 in dogs, six in farmed red foxes, two in wild red foxes, three in arctic foxes and one in Chinese raccoon dog). Among them, seven appeared to be novel: one silent in the dog, three missense and one silent in the red fox, one in the 3′‐flanking region in the arctic fox and one silent in the Chinese raccoon dog. In dogs and red foxes, the SNPs segregated as 10 and four haplotypes, respectively. Taking into consideration the published reports and results of this study, the highest number of missense polymorphisms was until now found in the dog (9) and red fox (7).     

Electroneurographic examination of the ulnar and radial nerves in the dog: reference values, biological variation and reproducibility

The radial and ulnar nerves were examined electrophysiologically in 90 normal dogs. In 66 of these dogs, aged between one and eight years, the reference values were established for 27 variables. Multicomponent sensory nerve action potentials were encountered at the proximal recording site in the ulnar nerve in 68 per cent of the dogs in the reference group and in the radial nerve in 26 per cent. Differences between the sexes were not significant, nor were differences between two breeds of similar body size. There were no significant age related differences between the ages of one and eight years. Limb length, measured as the distance between sensory stimulation site (digits) and proximal recording site (elbow), was found to have a significant effect on the velocity, amplitude, number of positive peaks and duration of the nerve action potentials. The variation in results of repeated measurements of velocities ranged from 0 to 11 per cent. The relative error in velocities due to errors in measurement of distance and latency ranged from 1 to 12 per cent.     

Normal canine excretory urogram: effects of dose, time, and individual dog variation

Ten healthy, young, adult mongrel dogs were given sodium iothalamate at dose levels of 200, 400, and 800 mg of iodine/0.45 kg of body weight on separate occasions by rapid IV injection; urinary bladders of the dogs were empty before injections were begun. Seven of the ten dogs were given an additional dose of sodium iothalamate (400 mg of iodine/0.45 kg) with the bladder partially distended with sterilized saline solution. Ventrodorsal abdominal radiographs were obtained immediately and at 5, 10, 20, 40, 60, and 120 minutes after injection of contrast medium. The kidneys, renal pelves, pelvic diverticula, and ureters were evaluated for radiographic density (radiopacity). The lengths and widths of the kidneys, pelves, and diverticula and the width of the ureters were determined, and those measurements were standardized by dividing the values by the corresponding length of the second lumbar vertebral body. From these evaluations, it was determined that postinjection radiographs should be obtained immediately and at 5, 20, and 40 minutes. The optimal dose of contrast medium was 400 mg of iodine/0.45 kg of body weight. It was also determined that the dose of contrast medium, as well as the time of postinjection radiography, significantly influenced many of the measurements (both linear and density) in the excretory urogram of normal dogs. Values for the measurements of the urinary structures based on the results of the present study are also presented.     

Limb fractures in the dog and cat. VI. Complications of fractures in the dog

Abstract— A review is made of possible complications of fractures which may occur in the dog. The complications are classified and then the subject is dealt with under the headings of mal-union, delayed-union, non-union and prevention of complications. Emphasis is given to metallurgical problems and post operative care. Résumé— Un compte-rendu est établi sur les complications éventuelles des fractures qui pourraient arriver chez le chien. Les complications sont classifiées, le sujet est ensuite traîté sous le nom de mal-soudure, soudure-lente, non-soudure et prévention des complications. Les problème metallurgiques et les soins post-opérationnels sont soulignés. Zusammenfassung— Besprechung über mögliche Bruchkomplikationen, die bei Hunden und Katzen vorkommcn können. Die Komplikationen werden klassifiziert, wora ut die betreffenden Gegenstände unter den Titeln: schlech es Zusammenwachsen, verzögertes Zusammen wachsen, ausgebliebenes Zusammenwachsen und Komplikationsverhütung behandelt werden. Besonderes Gewicht wird auf metallurgische Probleme und postoperative Behandlung gelegt.     

Nitrite and nitrate pharmacokinetics in the dog, sheep, and pony.

Elimination kinetics of nitrite and nitrate in the dog, sheep, and pony were determined. The elimination half-lives of nitrite were 0.499, 0.475, and 0.566 hours in the dog, sheep, and pony, respectively; those of nitrate were 44.681, 4.233, and 4.821 hours. Apparent specific volumes of distribution (V'd) of nitrite were variable among the 3 species--1,623.7 ml/kg in the dog, 278.0 ml/kg in the sheep, and 191.6 ml/kg in the pony. The V'd of nitrate were less varied--dog, 238.5 ml/kg; sheep, 291.1 ml/kg; and pony, 209.3 ml/kg. In the in vitro studies on protein binding in canine plasma, the extent of nitrite-protein binding varied directly with concentrations of 5 to 25 mug of NO2 minus/ml (4.5 to 13.6% bound), but inversely with concentrations of 50 to 100 mug of NO2 minus/ml (9.8 to 8.8% bound). Less than 1% of nitrate was bound to canine plasma at equimolar concentrations (5 to 100 mug of NO3 minus/ml).     

Polymorphism of the DQA2 gene in goats

Variation in the caprine DQA2 gene was investigated using PCR-single-strand conformational polymorphism (SSCP) and DNA sequencing. Eleven DQA2 alleles were defined by SSCP patterns from 23 goats. All the caprine alleles shared high sequence homology to ovine DQA2 sequences, and exhibited a pattern of polymorphism similar to DQA2 alleles from sheep and cattle but different from caprine DQA1 sequences. Thirty-eight AA positions in the alpha1 domain of caprine DQA2 molecules were polymorphic, and a high degree of polymorphism was observed in the putative antigen-binding region, with 74% of the positions being polymorphic. Phylogenetic analysis of caprine, ovine, and bovine DQA sequences revealed that the caprine DQA2 sequences identified here grouped with ovine DQA2, bovine DQA2, DQA3, and DQA4 sequences but are separate from the group of caprine DQA1 alleles. Nine of the caprine DQA2 sequences were more similar to ovine DQA2 alleles, whereas the remaining two were more closely related to ovine DQA2-like and bovine DQA3 alleles. This finding suggests that the caprine DQA2 sequences may represent two loci, which probably arose by either gene duplication or gene conversion events. Allelic lineages were evident for both DQA2 and DQA2-like loci, supporting the trans-species mode of evolution of major histocompatibilitly complex genes. The high level of polymorphism and similarity between caprine and ovine DQA2 alleles suggests that the DQA2 gene may play an important role in immune responses to shared pathogens.     

Influence of litter size and breed on variation in length of gestation in the dog

Summary

The variation in the length of gestation, the period from mating until parturition, was studied in 77 dogs of different breeds; the time for mating was determined by measuring peripheral blood progesterone levels. The mean length of gestation was 62.1 ± 0.2 (S.E.M.) days, with a variation of 11 days. The number of pups appeared to influence the length of gestation. Length of gestation was negatively correlated (r = ‐0.96, P < 0.001, n = 44) with litter size in litters with 7 or fewer pups. The intra‐breed variation in length of gestation in the five breeds represented by five or more bitches was 3 ‐ 6 days. The mean gestation of Alsatians (60.1 ± 0.5, n = 9) was shorter (P < 0.005) than that of the other breeds combined (62.3 ± 0.3, n = 68). The primiparous/multiparous status of the bitch did not influence the length of gestation.     

Mitochondrial DNA variation of the dog hookworm Ancylostoma caninum in Brazilian populations

The mitochondrial cytochrome oxidase I gene was partially sequenced for 164 Ancylostoma caninum individuals, originating from five different localities in Brazil, with the aim of describing the genetic diversity and genetic structure of Brazilian hookworm populations. Allelic and nucleotide diversity were moderate (overall h=0.88 and pi=0.016) and were similar among cities. There was moderate genetic differentiation among the populations sampled (approximately Phi(ST)=0.12) and a weak but nonsignificant correlation between geographical and genetic distance. This genetic structure was similar to that observed among populations of the human hookworm, Necator americanus, but distinct from that typically found in trichostrongylid nematode parasites of livestock. Thus, a pattern of different genetic structures among different groups of nematodes is emerging. We also observed a few individuals that had a highly divergent mtDNA sequence (almost 7% sequence divergence from the other sequences). These results in combination with data from other studies suggest that A. caninum populations worldwide consist of a mix of previously differentiated populations, or perhaps even cryptic species. This study contributes to the knowledge of genetic structure and diversity of hookworms, which in turn will be useful in developing methods for their control.     

Allelic variation of the D4 dopamine receptor polymorphic region in two dog breeds, Golden retriever and Shiba

The D4 dopamine receptor (D4DR) polymorphic region, which is possibly related to the personality trait known as novelty seeking in humans, was examined in 34 dogs from two breeds (Golden retriever and the Japanese indigenous breed, Shiba) by the polymerase chain reaction (PCR), and the DNA sequences of each allele were determined. The polymorphic region of the dog D4DR gene was composed of 39- and 12- base pair (bp) units, and four alleles (A-D) were identified based on the number and/or order of these units. Intra- and inter-breed allele variations were observed. The frequency of the short A allele was dominant (78.9%) in the Golden retriever, while the long D allele was most common (46.7%) in the Shiba. These findings suggested that the allele frequency varied significantly between different breeds, and that analysis of the polymorphism in D4DR might be of use for understanding the behavioral traits of dogs.     

Unusual anatomic variation of bilateral ectopic ureters in a dog

An unusual anatomic variation of bilateral ectopic ureters was diagnosed in a 6-week-old female Siberian Husky with urinary incontinence. Assessment during surgery revealed bilateral ectopic ureters with a common opening in the proximal portion of the urethra. Ureteroneocystostomy was performed bilaterally. After surgery, intermittent urinary incontinence continued, but was less severe. After resection of a persistent hymen in the 6-month-old dog, incontinence appeared to resolve, but then recurred, and has been controlled by phenylpropanolamine administration.