CONTRAST-ENHANCED ULTRASONOGRAPHY FOR CHARACTERIZATION OF CANINE FOCAL LIVER LESIONS

In six normal beagles and 27 dogs with spontaneous focal or multifocal liver lesions, contrast-enhanced ultrasonography using Sonazoid^® was performed. Sonazoid^® is a newly developed second-generation contrast agent with the ability to be used for real-time contrast imaging along with parenchymal imaging. An appropriate protocol for the evaluation of all three phases (arterial, portal, and parenchymal) was established based on the results for normal beagles. By evaluation of the echogenicity of hepatic nodules during the arterial and parenchymal phases it was possible to differentiate malignant tumors from benign nodules with very high accuracy. In 15 of 16 dogs diagnosed as malignant tumors, nodules were clearly hypoechoic to the surrounding normal liver during the parenchymal phase. Additionally, malignant tumors had different echogenicity compared with the surrounding normal liver during the arterial phase in 14 of 15 dogs. In the portal phase, there were no characteristic findings. Contrast-enhanced ultrasonography with Sonazoid^® appears to improve the characterization of canine focal and multifocal hepatic lesions.     

Hemodynamic and Electrocardiographic Effects of Magnesium Sulfate in Healthy Dogs

We investigated the effects of graded dosages of magnesium given i.v. to anesthetized dogs on blood pressure, cardiac output, and electrophysiology. Magnesium was infused at 0.12 mEq/kg/minute until ventricular fibrillation occurred naturally or was provoked by programmed electrical stimulation or until arrest of the sinuatrial node in 8 dogs. Plasma total magnesium concentrations doubled in 1 minute of that infusion rate, and a hemodynamically safe plasma concentration of 12.2 mEq/L was achieved after 16 minutes of infusion. Heart rate, inotropy, lusitropy, and cardiac output increased up to a cumulative infusion dosage of magnesium of 1.0-2.0 mEq/kg, which produced plasma magnesium concentrations of 8.5-12.2 mEq/L (n = 5). Above the cumulative infusion dosage, inotropy decreased and lusitropy increased until death occurred between cumulative infusion dosages of 5.9 mEq/kg and 10.9 mEq/kg. Arterial pressure and vascular resistance decreased, and PQ interval and QRS complex increased, in a dose-dependent fashion. The relationship between ionized and total magnesium was y = 0.624x - 0.542 (r2 = .986), where y is ionized and x is total magnesium in mEq/L in 3 dogs. In conclusion, a cumulative infusion dosage of 0.1-0.2 mEq/kg of magnesium may be given without changing hemodynamic parameters, but with higher cumulative infusion doses heart rate accelerates. Hemodynamic parameters except those related to blood pressure continued to increase to a cumulative infusion dosage of 2.0 mEq/kg. At higher cumulative infusion dosages dogs became hypotensive and the PQ interval was prolonged. However, dangerous arrhythmias were not provoked until a total dosage of 3.9 mEq/kg.     

Purinergic P2X7 receptor antagonist ameliorates intestinal inflammation in postoperative ileus

Postoperative ileus (POI) is a postsurgical gastrointestinal motility dysfunction caused by mechanical stress to the intestine during abdominal surgery. POI leads to nausea and vomiting reduced patient quality of life, as well as high medical costs and extended hospitalization. Intestinal inflammation caused by macrophages and neutrophils is thought to be important in the mechanism of POI. Surgery-associated tissue injury and inflammation induce the release of adenosine triphosphate (ATP) from injured cells. Released ATP binds the purinergic P2X7 receptor (P2X7R) expressed on inflammatory cells, inducing the secretion of inflammatory mediators. P2X7R antagonists are thought to be important mediators of the first step in the inflammation process, and studies in chemically induced colitis models confirmed that P2X7R antagonists exhibit anti-inflammatory effects. Therefore, we hypothesized that P2X7R plays an important role in POI. POI models were generated from C57BL/6J mice. Mice were treated with P2X7R antagonist A438079 (34 mg/kg) 30 min before and 2 hr after intestinal manipulation (IM). Inflammatory cell infiltration and gastrointestinal transit were measured. A438079 ameliorated macrophage and neutrophil infiltration in the POI model. Impaired intestinal transit improved following A438079 treatment. P2X7R was expressed on both infiltrating and resident macrophages in the inflamed ileal muscle layer. The P2X7R antagonist A438079 exhibits anti-inflammatory effects via P2X7R expressed on macrophages and therefore could be a target in the treatment of POI.     

Comparison of in vitro vitellogenin synthesis among different nonylphenol products using primary cultures of tilapia hepatocytes

Effect of nonylphenol (NP) products from different companies on in vitro vitellogenin (VTG) synthesis was compared using tilapia ( Oreochromis mossambicus ) hepatocytes cultures. Addition of NP at a concentration of 10⁻³ M to the medium caused death of hepatocytes (NP-A and NP-B) and delay of monolayer formation (NP-C). No cell death was observed at a concentration of 10⁻⁴ M (NP-A, -B and -C) but cell adhesion was slower than control. These results suggest that high concentration of NP is toxic against tilapia hepatocytes. When effects of estradiol-17β (E₂, 10⁻⁷ M) and NP (10⁻⁴ M) on in vitro VTG synthesis were examined, addition of E₂ and NP-A and NP-B to the media resulted in elevation of VTG. NP-C did not induce VTG in the medium. Co-treatment of NP-B and tamoxifen, a non-steroidal anti-estrogen, reduced VTG synthesis. These results suggest that NP has estrogenic potential in primary cultures of tilapia hepatocytes and acts through binding to the estrogen receptor, and that there is a difference in the induction level of VTG among different NP products.     

Genetic information of three pure lines of Porphyra yezoensis (Bangiales, Rhodophyta) obtained by AFLP analysis

Porphyra (Bangiales, Rhodophyta), which includes several valuable marine crops, has recently received great interest as a model plant for fundamental and applied studies in marine sciences. Amplified fragment length polymorphisms (AFLPs) are a robust and efficient means for genetic mapping, linkage analysis of genetic characters for breeding and population studies in land plant genomes. To examine whether AFLPs are applicable as genetic markers in the present study, we detected AFLP markers with three pure lines in order to promote genetic analysis in Porphyra yezoensis . The following five sets of AFLP primer pairs (E-AA, M-CAA) (E-AA, M-CAC) (E-AA, M-CAG) (E-AA, M-CAT) (E-AA, M-CTA) were tested with template DNAs from three pure lines and they showed a total of 227 bands. This suggests that AFLP markers are promising tools for genetic analysis in Porphyra .     

Urinary corticoid to creatinine ratios using IMMULITE 2000 XPi for diagnosis of canine hypercortisolism

The urinary corticoid to creatinine ratio (UCCR) is one of the most commonly used screening tests for canine hypercortisolism (HC). In this study, a reference interval was established for UCCR using IMMULITE 2000 XPi, the latest chemiluminescence enzyme immunoassay. The diagnostic performance of this method for UCCR in canine HC was also evaluated. The median UCCR was 1.06 × 10⁻⁵ (range: 0.28–2.49) for 58 healthy dogs, and an upper reference limit of 1.98 × 10⁻⁵ (90% confidence interval: 1.76–2.15) was determined. The median UCCR in the 12 dogs with HC (7.38 × 10⁻⁵, range 1.86–29.98) was significantly higher than that in the 16 dogs with mimic-HC (1.59 × 10⁻⁵, range 0.47–3.42, P<0.001). The area under the curve for UCCR to differentiate HC dogs from mimic-HC dogs was 0.971, with a sensitivity of 91.7% and specificity of 100% when the cut-off value was set at 3.77 × 10⁻⁵. The UCCR of 16 paired urine samples collected at home and in hospital showed that the UCCR of samples collected in the hospital was significantly higher than that of samples collected at home (mean difference 3.30 × 10⁻⁵, 95% confidence interval: 0.70–5.90, P=0.001). In summary, we established the upper reference limit for UCCR using IMMULITE 2000 XPi in dogs and confirmed that UCCR is a useful diagnostic test for HC in dogs if urine samples are collected at home.     

Development of vaccine strains of H5 and H7 influenza viruses

To establish vaccine strains of H5 and H7 influenza viruses, A/duck/Hokkaido/Vac-1/04 (H5N1) [Vac-1/04 (H5N1)], A/duck/Hokkaido/Vac-3/07 (H5N1) [Vac-3/07 (H5N1)], and A/duck/Hokkaido/ Vac-2/04 (H7N7) [Vac-2/04 (H7N7)] were generated from non-pathogenic avian influenza viruses isolated from migratory ducks. Vac-1/04 (H5N1) and Vac-3/07 (H5N1) were generated by genetic reassortment between H5N2 or H5N3 virus as an HA gene provider and H7N1 or H6N1 viruses as an NA gene provider. Vac-2/04 (H7N7) was a genetic reassortant obtained using H7N7 and H9 N2 viruses to give high growth character of the H9N2 virus in chicken embryonated eggs. The results of sequence analyses and experimental infections revealed that these H5N1 and H7N7 reassortant viruses were non-pathogenic in chickens and embryos, and had good growth potential in embryonated eggs. These viruses should be useful to develop vaccines against H5 and H7 highly pathogenic avian influenza viruses.     

Changes in peripheral blood mononuclear cells after calving in lactating cows with serious decrease of body weight before and after calving

The aim of this study was to clarify the hormonal and immunological changes in periparturient dairy cows with excessive weight loss following calving. We analyzed leukocyte populations and the peripheral blood mononuclear cell (PBMC) mRNA of IFN-gamma, IL-4, growth hormone (GH)-receptor (R) and insulin -R and measured the GH and insulin concentrations. Ten dairy cows fed in one herd were used in this study and were divided into two groups. Five cows that experienced loss of body weight following calving of over 10% comprised the Weight Loss Group, and the remaining five cows, which experienced loss of body weight of 5% or less following calving, served as the Control Group. The Weight Loss Group had high serum cholesterol and low blood urea nitrogen levels compared with the Control Group throughout the period of observation. In regard to the leukocyte populations, there were significantly fewer CD4(+)CD45R-T cells in the Weight Loss Group 1 to 2 months after calving compared with the Control Group. The percentage of IFN-gamma/IL-4 among PBMCs in the Weight Loss Group tended to be lower than in the Control Group throughout the observation period. In the Weight Loss Group, the levels of GH-R during month 2 were lower than in the Control Group. We concluded that excessive loss of body weight in dairy cows following calving is associated with depressed cellular immune function.