Evaluation of caudal vena cava size using computed tomography in dogs under general anesthesia.

This study investigated the association between caudal vena cava (CVC) size and circulatory dynamics in dogs using computed tomography (CT) under general anesthesia. The subjects were 104 dogs who had undergone CT under general anesthesia in the past. The ratio of short diameter of the CVC to aortic diameter (CVCS/Ao) and the ratio of long to short diameter of the CVC (CVCL/CVCS) in the thorax and abdomen, respectively, were calculated using factors such as mean blood pressure (MBP), shock index (SI), anemia, hypoproteinemia, presence of intra-abdominal mass, and cardiac disease. There was a significant but negligible negative correlation between CVCS/Ao and MBP. In contrast, no significant correlation was found between CVC size and SI. The low MBP group had significantly higher CVCS/Ao of the thorax than the normal MBP group. The group with intra-abdominal mass had significantly lower CVCS/Ao of the abdomen than the group without intra-abdominal mass. The group with cardiac disease had significantly lower CVCL/CVCS of the thorax than the group without cardiac disease. In multiple regression analysis, low MBP, cardiac disease, intra-abdominal mass, and anemia were significant factors for CVCS/Ao of the thorax, CVCL/CVCS of the thorax, CVCS/Ao of the abdomen, and CVCL/CVCS of the abdomen, respectively. In conclusion, CVC size assessment using CT in dogs under general anesthesia is influenced by various factors.

Homozygosity of single nucleotide polymorphisms in the 3' region of the canine estrogen receptor 1 gene is greater in Toy Poodles than in Miniature Dachshunds and Chihuahuas.

Differences in the distribution of single nucleotide polymorphisms (SNPs) and haplotypes in the estrogen receptor α gene (ESR1) were examined in Miniature Dachshunds (n = 48), Chihuahuas (n = 20) and Toy Poodles (n = 18). Five DNA fragments located in the 40-kb region at the 3' end of ESR1 were amplified by polymerase chain reaction and were directly sequenced. We compared allele, genotype and estimated haplotype frequencies at each SNP in the 3' end of ESR1 for these three breeds of small dog. The frequency of the major allele and the genotype frequency of the major allele homozygotes, were significantly higher in Toy Poodles for five SNPs (SNP #5, #14-17) than in Miniature Dachshunds, and significantly higher in Toy Poodles than Chihuahuas for three SNPs (SNP #15-17). A common haplotype block was identified in an approximately 20-kb region encompassing four SNPs (SNPs # 14-17). The frequencies of the most abundant estimated haplotype (GTTG) and GTTG homozygotes were significantly higher in Toy Poodles than in the other two breeds. These results imply that homozygosity for the allele, genotype and haplotype distribution within the block at the 3' end of ESR1 is greater in Toy Poodles than in Miniature Dachshunds and Chihuahuas.

Comparison of testosterone and insulin-like peptide 3 secretions in response to human chorionic gonadotropin in cultured interstitial cells from scrotal and retained testes in dogs.

Levels of testosterone and insulin-like peptide 3 (INSL3) secretions in response to different doses of human chorionic gonadotropin (hCG) in cultured interstitial cells were compared between retained and scrotal testes in dogs. Retained (n=10) and scrotal (n=9) testes were obtained from small-breed dogs. The testicular tissues were dispersed in Dulbecco's Modified Eagle Medium with Ham's nutrient mixture containing 2000 PU/ml dispase II and 10% fetal bovine serum. The cells were plated with differing concentrations (0-10 IU/ml) of hCG for 18 h in multiwell-plates. Testosterone and INSL3 in the same spent medium were measured by enzyme-immunoassays (EIA). A new EIA with a reliable detection range of 0.025-5 ng/ml was developed in order to measure canine INSL3 in culture medium. Dose-dependent stimulation of testosterone by hCG was observed in the cells of both retained and scrotal testes. The incremental rate of testosterone secretion was significantly lower at 0.1, 1 and 10 IU/ml hCG in the cells of retained testes than in scrotal testes, however. INSL3 secretion was significantly stimulated at 10 IU/ml hCG relative to unstimulated controls comprising cells of scrotal testes; no such stimulation was observed in the cells of retained testes. At 10 IU/ml hCG, the incremental rate of INSL3 was significantly lower in the cells of retained testes than scrotal testes. These results suggest that LH-induced secretory testosterone and INSL3 responses are lower in the interstitial cells of retained testes than of scrotal testes. Furthermore, the high concentrations of LH may acutely stimulate INSL3 release in scrotal testes of dogs, but not in retained testes.

Analysis of single nucleotide polymorphisms in the 3' region of the estrogen receptor 1 gene in normal and cryptorchid Miniature Dachshunds and Chihuahuas.

This study was performed to examine the distribution of single nucleotide polymorphisms (SNPs) and estimated haplotypes in the canine estrogen receptor (ER) alpha gene (ESR1) and the association of them with different phenotypes of cryptorchidism (CO) in Miniature Dachshunds and Chihuahuas. Forty CO and 68 normal dogs were used, and CO was classified into unilateral (UCO; n=33) and bilateral CO (BCO; n=5) or into abdominal (ACO; n=16) and inguinal CO (ICO; n=22). Thirteen DNA fragments located in the 70-kb region at the 3' end of ESR1 were amplified by PCR and sequenced to examine 13 SNPs (#1-#13) reported in a canine SNP database. Ten SNPs (#1-#4, #7, #8, #10-#13) were not polymorphic, and 5 new SNPs (#14-#18) were discovered. A common haplotype block in normal, CO and CO phenotypes was identified for an approximately 20-kb region encompassing 4 SNPs (#14-#17). Allele, genotype and haplotype frequencies in CO without classification by phenotype and also in UCO, ACO and ICO phenotypes were not statistically different from the normal group. Significant differences in genotype frequencies and homozygosity for the estimated GTTG haplotype within the block were observed in BCO compared with the normal group, although the number of BCO animals was small. Our results demonstrate that the examined SNPs and haplotypes in the 3' end of canine ESR1 are not associated with unilateral, abdominal and inguinal CO phenotypes and CO per se in Miniature Dachshunds and Chihuahuas. Further studies are necessary to suggest a clear association between the ESR1 SNPs and bilateral CO in dogs.