Evaluation of intestinal intramucosal pH,arterial and portal venous blood gas values,and intestinal blood flow during small intestinal ischemia and reperfusion in dogs

OBJECTIVES: To determine whether small intestinal ischemia and reperfusion affects intestinal intramucosal pH (pHi), arterial and portal venous blood gas values, and intestinal blood flow (IBF) and to investigate relationships between regional intestinal tissue oxygenation and systemic variables in dogs. ANIMALS: 15 healthy adult Beagles. PROCEDURE: Occlusion of superior mesenteric artery (SMA) for 0, 30, or 60 minutes, followed by reperfusion for 180 minutes, was performed; IBF, pHi, arterial and portal venous blood gas values, arterial pressure, and heart rate were measured at various time points; and intestinal mucosal injury was histologically graded. RESULTS: Occlusion of the SMA induced significant decreases in pHi and IBF. After the release of the occlusion, IBF returned rapidly to baseline values, but improvement in pHi was slow. Arterial and portal venous blood gas analyses were less sensitive than tonometric measurements of pHi, and there was no correlation between results of blood gas analyses and tonometric measurements. Histologic score for intestinal mucosal injury increased significantly, depending on duration of ischemia, and there was a correlation between tonometric results and the histologic score. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that it is difficult to accurately evaluate local oxygenation disorders by monitoring at the systemic level, whereas clinically pHi is the only reliable indicator of inadequate regional intestinal tissue oxygenation in dogs.     

Hepatic tyrosine aminotransferase activity is affected by chronic heat stress and dietary tyrosine in broiler chickens

1. Two experiments were conducted to investigate the impact of high temperature and dietary tyrosine (Tyr) content on performance and activity of hepatic tyrosine aminotransferase (EC 2.6.1.5.), an enzyme that catalyses the first step in the metabolic degradation of Tyr in broiler chickens. 2. Two-week-old birds were allocated to one of three temperature treatments: 24 degrees C (control), 36 degrees C (heat stress, HS) and 24 degrees C pair-fed (24PF) for 2 weeks and fed on diets containing 100% (Experiment 1) and 50, 100 and 200% (Experiment 2) of the NRC requirement for Tyr. 3. In Experiment 1, exposure of chickens to 36 degrees C for 2 weeks caused significant increase in hepatic tyrosine aminotransferase activity but no significant change in activity of hepatic phenylalanine 4-hydroxylase (EC 1.14.16.1) (an enzyme that catalyses conversion of phenylalanine to Tyr) compared with the 24PF birds. No significant changes attributable to heat stress were detected in hepatic glutamic-oxaloacetic transaminase (EC 2.6.1.1) activity. 4. In Experiment 2, heat stress caused reductions in weight gain and feed intake in chickens on all diets, compared with their control counterparts. Hepatic tyrosine aminotransferase activity was increased by heat stress compared with their 24PF counterparts in chickens fed on the 100 and 200% Tyr diets, while in chickens fed the 50% Tyr diet, it was reduced by heat stress. 5. From these results, it is suggested that hepatic tyrosine aminotransferase activity is affected by heat stress and dietary Tyr content and the increased tyrosine aminotransferase activity with, in part, relatively low phenylalanine hydroxylase activity in hepatic tissues may be involved in the Tyr metabolism characteristic of heat-stressed chickens.     

Genetic and biological comparison of tick-borne encephalitis viruses from Hokkaido and far-eastern Russia

We compared the biological properties of Oshima 5-10 (tick-borne encephalitis [TBE] virus isolated in Hokkaido, Japan) and Sofjin-HO (Far-Eastern subtype TBE virus) including plaque formation, virus replication and virus protein synthesis in BHK-21 cell cultures to reveal strain differences. We also determined the complete nucleotide sequences of both strains and compared the deduced amino acid sequences. Plaques of Oshima 5-10 were smaller than those of Sofjin-HO. Virus titers in culture fluid of Oshima 5-10 were 1/100 of those of Sofjin-HO at 9 and 12 hr after infection. Less viral protein and RNA syntheses of strain Oshima 5-10 was observed than with Sofjin-HO. Genetic analysis revealed 1.4% of amino acids to differ with Sofjin-HO. No difference between the two strains was detected in the motif sequence of the viral enzyme, cleavage sites of viral protein or glycosylation sites of NS1.     

Electrocorticographic and histological findings in a Shetland sheepdog with intractable epilepsy

A Shetland sheepdog with epilepsy refractory to antiepileptic drugs was brought to the division of Veterinary Radiology at Nippon Veterinary and Animal Science University. Scalp electroencephalography and computed tomography was performed, but no abnormality was detected in either examination. To obtain detailed information, electrodes were implanted on the dura mater, and the electrocorticogram (ECoG) was recorded. In the ECoG, sporadic spikes were detected in the left parietal region, suggesting the presence of the epileptic focus in this region. After the dog's death, abnormalities of gyri were found in the region where spikes were detected in the ECoG. On histopathological examination, laminar malacia of the cingulate gyrus was observed. Furthermore, in the hippocampus, neuronal loss of pyramidal cells was observed.     

Effect of natural and synthetic retinoids on the proliferation and differentiation of three canine melanoma cell lines

The effect of two natural retinoids and synthetic retinoids with or without retinoid synergists on the proliferation and differentiation of 3 melanoma cell lines were investigated in vitro. No retinoids showed significant growth inhibitory effect on these cell lines when used alone, however, cell differentiation and significant growth inhibition were observed when treated with a combination of retinoids and a retinoid synergist. This study may suggest that, though the cells showed low susceptibilities when retinoids were treated alone, the combination of retinoids and a retinoid synergist may be effective to control the growth of canine melanoma cell lines.     

Influence of antibiotics used as feed additives on the immune effect of erysipelas live vaccine in swine

To investigate the influence of antibiotics used as feed additives on the immune response to erysipelas live vaccine, the pig inoculation test was applied. Avilamycin, oxytetracycline quaternary salt, enramycin, virginiamycin and tylosin phosphate were selected as test antibiotics. Five experimental feeds containing each antibiotic at the highest concentration permitted for feed additives in Japan, and the basal diet lacking antibiotics were examined. Twenty-nine pigs were divided into six groups. At first all the groups were fed with the antibiotic-free basal diet for 7 days, and then each group received the experimental feeds. On the 14th day after feeding with test feeds all the pigs, except for one control pig in each group, were immunized with the vaccine and all the pigs were then challenge-exposed to a virulent strain of Erysipelothrix rhusiopathiae 14 days after vaccination. The clinical response was observed every day for 14 days. In all the groups, most of the vaccinated pigs did not develop any clinical signs of acute erysipelas after the challenge exposure, whereas non-vaccinated control pigs died or showed severe generalized erythema with profound depression and anorexia. No differences in the protection against the challenge exposure were observed among the groups. Therefore, the present results suggest that these selected antibiotics would not interfere with the immune effect of the vaccine if given at the usual concentrations used for feed additives.     

Production of transgenic rabbits using centrifuged pronuclear zygotes

Superovulation of female rabbits was induced by subcutaneous injection(s) of porcine FSH. Zygotes were recovered 17 to 19 hr after hCG injection and were classified into two categories under a microscope equipped with Nomarski interference-contrast optics at x 200 magnification: (A) zygotes with clearly visible pronuclei, or (B) zygotes with visualized pronuclei after 10 min centrifugation at 12,000 x g. No significant difference between strains was found in the proportion of category-A zygotes (JW 72.6% vs NZW 79.3%). Pronuclei of category-A zygotes were located in the center of the cytoplasm, and the pronuclei of category-B zygotes were slightly moved by centrifugation toward the mass of cytoplasmic lipid droplets. Exogenous DNA solution (5 microg/ml of fusion gene composed of bovine alphaS1-casein promoter and human growth hormone structural gene) was microinjected into the pronucleus of the JW zygotes. The pronucleus of category-A zygotes with a mean volume of 7.4 pl swelled up to 16.6 pl (132% increase), while that of category-B zygotes with a mean volume of 6.1 pl swelled up to 15.9 pl (148% increase). Nevertheless, similar proportions of category-A and category-B zygotes developed into offspring after transfer to recipient females (11.1 and 11.2%, respectively). The efficiency to produce hGH-carrying transgenic rabbits was 0.9% (2/235) from category-A zygotes and 0.5% (1/215) from category-B zygotes (P>0.05). To date, transgenic rabbits have been produced without centrifugation of pronuclear zygotes. However approximately 25% of fertilized rabbit zygotes can be used for DNA microinjection after they have been centrifuged to visualize their pronuclei.     

In vitro but not in planta encapsidation of Rice gall dwarf virus core particles by the outer capsid P8 protein of Rice dwarf virus expressed in transgenic rice plants

Transencapsidation of the Rice gall dwarf virus (RGDV) inner core by the Rice dwarf virus (RDV) outer capsid P8 protein was examined in vitro and in planta. When RGDV core particles were incubated with an extract from RDV P8-transgenic rice leaf tissue, RDV P8 encapsidated the RGDV core particles to form double-shelled virus-like particles in vitro. In contrast, when RDV P8-transgenic rice plants were inoculated with RGDV, progeny RGDV particles contained RGDV P8 but RDV P8 was not detectable in the virions. No significant differences were found in acquisition by the vector insects and subsequent transmission rates between RGDV infecting nontransgenic rice plants and those infecting RDV P8-transgenic rice plants. These results indicate that mechanisms of and/or requirements for interactions between P8 and the inner core particles of phytoreoviruses differ between in vitro and in planta.     

Effects of Shengmai San on oxidative damage in mentally stressed mice

AIM: To investigate the preventive effects of Shengmai San (SMS) on oxidative damage in mentally stressed mice.METHODS: An oxidative stress mouse model was established by moustache-removed. Protein carbonyl and thiobarbituric acid reactive substance (TBARS) formation were determined as the oxidative stress markers.RESULTS: (1)Moustache-cut was founded to significantly enhance the behavioral movements of mice, especially large movements (movement 2 and rearing). SMS pre-administration inhibited the accelerated movements. (2) Protein carbonyl was increased in brain, heart, liver and kidney. TBARS in liver and heart increased in the moustache-cut mice, but SMS pretreatment inhibited the increased protein carbonyl and TBARS.CONCLUSION: SMS has the preventive effects on oxidative damage induced by emotional stress.