Effect of age on myocardial function assessed by two-dimensional speckle-tracking echocardiography in healthy beagle dogs

ObjectivesThe objective of this study was to evaluate the effect of age on myocardial function assessed by two-dimensional speckle-tracking echocardiography (2D-STE) in healthy dogs.AnimalsThirty-two healthy Beagles were used.MethodsMyocardial function was assessed in each dog by using 2D-STE, and the results were compared between young and old dogs.ResultsThe myocardial deformations in systole, besides the apical rotation rate, were not significantly different between young and old dogs. In contrast, the early diastolic circumferential strain rate, basal rotation rate, and torsion rate were significantly lower in old dogs than in young dogs (P = 0.03, P = 0.033, and P = 0.015, respectively). Late diastolic longitudinal and radial strain rates were significantly higher in old dogs than in young dogs (P = 0.002 and P = 0.018, respectively).ConclusionsYoung and old dogs showed similar systolic myocardial deformations, but significant differences in the values of some diastolic deformation variables were found between young and old dogs, highlighting the need for using age-matched control subjects in studies of diastolic function.     

Timing of Puberty and Its Relationship with Body Growth and Season in Male Raccoons (Procyon lotor) in Hokkaido

The raccoon (Procyon lotor), indigenous to North America, has naturalized in Japan as an invasive alien species, having been introduced into the country in the 1970s. In Hokkaido, the northernmost island of Japan, feral raccoons have been increasing in number and spreading throughout the island. The age at the onset of puberty for raccoons is important for estimating individual lifetime reproductive success and population growth. The present study investigated the timing of and potential factors affecting the onset of puberty in male raccoons in Hokkaido. External characteristics and histology of testes were studied in 151 male feral raccoons and in 1 captive juvenile. For the majority of feral yearling raccoons, prepubertal development began in May, and spermatozoa production began in October prior to their second mating season. However, some larger juveniles attained puberty during the juvenile period. The captive juvenile, which was fed throughout the winter, attained puberty only 11 months after birth. These results suggest that if male raccoons can achieve enough body growth before the first mating season, puberty can be attained early. In both juveniles and yearlings, spermatozoa production was only observed after autumn. This timing coincided with the recrudescence of seasonally active spermatogenesis in adult males. Therefore, attaining puberty in male raccoons appears to require both adequate body nutrient development and several environmental factors that control seasonal testicular changes.     

Self-EcoTILLING to identify single-nucleotide mutations in multigene family

TILLING (Targeting Induced Local Lesions IN Genomes) is a low-cost, high-throughput reverse genetic technique that employs a mismatch-specific endonuclease CEL-1 to discover induced point mutations in the genes of interest. The use of the TILLING technique to survey natural variation in genes is called EcoTILLING. Here, we report a modified EcoTILLING method for the discovery of mutations in multigene family, which we coin “Self-EcoTILLING” by using an allotetraploid Monochoria vaginalis ALS multigene family as an example. The mutations could be detected by TILLING of PCR products resulting from the primers specific to both Als1 and Als3 without involving the experimental step of mixture of reference and query DNA. Either of the two co-amplified loci could serve as reference DNA to the other. We demonstrate with this example that Self-EcoTILLING is a fast, reliable and economical technique of detecting single-nucleotide mutations in polyploid plants containing multigene family.     

Pharmacokinetics of fentanyl after single intravenous injection and constant rate infusion in dogs

OBJECTIVE: To determine the plasma concentration and define the pharmacokinetic characteristics of fentanyl (10 microg kg(-1)) administered as a single intravenous (IV) injection followed by: (a) no further drug; or (b) a constant rate infusion (CRI) of fentanyl 10 microg kg(-1) hour(-1) lasting 1, 3 or 4 hours in dogs. Animals Fourteen healthy adult beagles (seven males and seven females). EXPERIMENTAL DESIGN: Randomized cross-over design. MATERIALS AND METHODS: Dogs were randomly assigned to four treatment groups. Drugs were administered to each dog in a randomized cross-over design with at least a 14-day washout interval between experiments. All dogs received an IV loading dose of fentanyl (10 microg kg(-1)). One group received no further fentanyl. In others, the loading dose was followed by a CRI of fentanyl (10 microg kg(-1) hour(-1)) for 1, 3 or 4 hours. Blood samples were collected and plasma fentanyl concentrations determined using high-performance liquid chromatography-mass spectrometry. Plasma pharmacokinetic estimates were obtained by plotting plasma concentrations versus time data and by fitting the change in concentration to a pharmacokinetic model, using a purpose-built program written by the Graduate School of Pharmaceutical Sciences (Kyoto University) in Visual Basic (VBA) on Excel (Microsoft Corporation). RESULTS: Plasma fentanyl concentration decreased rapidly after single IV injection: the plasma concentration-time curve best fitted a two-compartment model. Pharmacokinetic variables for IV injection were characterized by a short distribution half-time (t1/2alpha was 4.5 minutes), a relatively long elimination half time (t1/2beta was 45.7 minutes), a large volume of distribution (approximately 5 L kg(-1)) and high total body clearance (77.9 mL minute(-1) kg(-1)). Stable plasma fentanyl levels were obtained in all CRI groups although pharmacokinetic variables were influenced by the duration of administration. CONCLUSIONS AND CLINICAL RELEVANCE: While this study clarified the pharmacokinetic features of rapid IV fentanyl injection and CRI in dogs, the plasma concentration achieving analgesia was not and so further research is needed. Further studies on the effects of other sedatives and/or anaesthetics on fentanyl's disposition are also required as the drug is commonly used with other agents.     

Maturation-associated changes in internal distribution and intra-ovarian microdistribution of tetrodotoxin in the pufferfish <Emphasis Type="Italic">Takifugu pardalis</Emphasis>

To clarify the maturation-associated accumulation profile of tetrodotoxin (TTX) in the female pufferfish Takifugu pardalis, specimens collected from Omura Bay, Nagasaki Prefecture, Japan, from November through December, 2014, were separated based on the histology of ovarian sections into four groups: yolk vesicle stage (Yv), yolk globule stage (Yg)-1, Yg-2, and Yg-3. TTX quantification in each tissue in each group by liquid chromatography–mass spectrometry revealed that the TTX concentration [mouse unit (MU)/g] in the ovary increased from Yv to Yg-1, and the TTX amount (MU/individual) in the ovary increased from Yg-1 through Yg-3. In Yv, TTX in the skin accounted for 86% of the total TTX in the body, whereas from Yg-1 through Yg-3, ovarian TTX accounted for 53–76% of the total. In female specimens collected from the same bay from February to May 2015, the TTX amount in the ovary markedly decreased after spawning, and the TTX amount in the liver increased. Immunohistochemical observation of the ovarian sections indicated that TTX localized mainly in the nucleus of immature oocytes, but then distributes to the yolk vesicles and yolk globules as maturation advances, and is partly transferred to the egg membrane as spawning approaches.     

Evaluation of the juice brix of wild sugarcanes (Saccharum spontaneum) indigenous to Japan

Modern sugarcane cultivars are derived from the interspecific crossing between Saccharum officinarum and wild sugarcane, Saccharum spontaneum. The introgression of valuable characteristics from wild sugarcane is recognized as extremely important, but this process typically requires long-term effort over multiple generations of backcrosses owing to the low sugar content of the initial interspecific hybrids. In this study, we aimed to identify Japanese wild sugarcanes with high juice brix in order to promote effective interspecific crossing of sugarcane. Sixty-four accessions from the Nansei Islands and 70 accessions from the Honshu were evaluated for juice brix. Wild sugarcanes with high juice brix were demonstrated to exist among wild sugarcanes indigenous to the Honshu. A significant difference was observed between the median juice brix values of wild sugarcanes of the Nansei Islands and those of the Honshu. The relationship between juice brix and stem traits was then examined in 20 wild sugarcanes, 10 each from the Nansei Islands and the Honshu. The reproducibility of juice brix value in both experiments was confirmed. In contrast to juice brix, stem traits, such as length, diameter, and volume, were typically smaller in wild sugarcanes from the Honshu. Moreover, a negative correlation was observed between the index of stem volume and juice brix. In this study, we identified outstanding wild sugarcanes with high juice brix. Using germplasms from the identified wild sugarcanes in interspecific crossing could contribute to the increases in both yield and sugar content.     

Effects of Lactic Acid Bacteria and Cellulase Additives at Different Temperatures on the Fermentation Quality of Corn and Guineagrass Silages

在两项试验中，用玉米（ＺｅａｍａｙｓＬ．）（试验１）和大黍（ＰａｎｉｃｕｍｍａｘｉｍｕｍＪａｃｑ．）（试验２）加入外加剂乳酸菌（ＬＡＢ）、支顶孢属纤维素酶（ＡＣ）及二者的结合（ＡＣ＋ＬＡＢ）做处理，不加外加剂为对照，分别在１０、２０、３０和４０℃恒温下青贮。结果表明，试验１中所有玉米青贮料，虽然与１０℃低温和４０℃高温时相比在２０和３０℃时的效果略好，但无论在何种外加剂和温度下都保存良好。在试验２中，ＡＣ与ＡＣ＋ＬＡＢ在所有温度处理下均比对照和ＬＡＢ更显著地提高了大黍青贮料的ｐＨ值和乳酸的含量，而且在４０℃时显著地减少了丁酸和挥发性碱性氮（ＶＢＮ）的含量。在各个温度水平中，外加剂乳酸菌对发酵均无甚影响。无论是否加入外加剂，在３０℃的所有大黍青贮料的丁酸含量均最高。与对照和加入ＬＡＢ的相比，单独加入ＡＣ及其与ＬＡＢ结合，均使玉米和大黍青贮料中的结构性醣类有部分的降解，并减低了ＮＤＦ和ＡＤＦ的含量。但温度对ＡＣ的降解能力无显著影响。     

Relationship between retinoic acid receptor alpha gene expression and growth-inhibitory effect of all-trans retinoic acid on canine tumor cells

Retinoids show antitumor effects on human acute promyelocytic leukemia and other tumors via retinoid receptors. In dogs, the role of retinoid receptors in inhibiting tumor development remains unclear. To evaluate the correlation between the degree of expression of retinoic acid receptor alpha (RARalpha) mRNA and the antiproliferative effects of all-trans retinoic acid (ATRA) treatments, expression analysis of RARalpha mRNA and cell growth inhibition assay were performed on 17 established canine tumor cell lines, including 6 mammary gland tumor (MGT) cell lines, 3 osteosarcoma cell lines, 5 melanoma cell lines, and 3 mast cell tumor (MCT) cell lines. Among the cell lines investigated, all 3 MCT cell lines showed high expression of RARalpha, and the most effective cell growth inhibition was observed in ATRA-treated MCT cell lines. However, remarkable antiproliferative effects of ATRA treatments were not observed on other tumor cell lines with moderate or low RARalpha mRNA expression. As a result of the relationship between RARalpha mRNA expression and ATRA treatment with regression analysis, statistically significant correlation was suggested. Furthermore, real-time quantitative polymerase chain reaction analysis of RARalpha was performed on MCT tissue samples of dogs with spontaneous disease, and 5 of 9 tissues showed high expression. These results suggest that ATRA may be an effective antitumor agent for MCT in dogs, and that prior measurement of expression of RARalpha mRNA may be a good indicator of the effectiveness of ATRA treatment.     

Urinary lipid production profile in canine patients with splenic mass

Polyunsaturated fatty acids (PUFAs), including arachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), are metabolized to various lipid mediators. The profile of these lipid metabolites excreted into the urine reflects inflammatory state of the body and disease conditions. In this study, we quantified 156 types of lipids in urine samples of dogs with splenic mass, using liquid chromatography-tandem mass spectrometry. We found that metabolites of prostaglandin (PG) E₂, F_2α, and D₂, 8-iso-PGF_3α, lyso-platelet activating factor, and 14,15-leukotrien C₄ significantly increased in urine samples of dogs with splenic mass compared to that of healthy dogs. These observations may reflect general inflammatory responses and will help better understanding of the canine splenic mass.     

Effects of dopamine, dobutamine, amrinone and milrinone on regional blood flow in isoflurane anesthetized dogs

The effects of cyclic AMP increasing cardiotonics (dopamine, dobutamine, amrinone and milrinone) on the blood flow in most organs were compared using colored microsphere technique in isoflurane-anesthetized dogs. Dopamine increased blood flow in ventricular myocardium. Furthermore dopamine induced the increase in blood flow in intestine and kidney at low to middle dose, but not at high dose. Dobutamine induced the highest increase in blood flow in ventricular myocardium and skeletal muscle among the drugs evaluated at middle and high doses. Amrinone and milrinone increased blood flow in ventricular myocardium almost same with catecholamines, and milrinone decreased vascular resistance moderately in most other organs. Milrinone might be more useful than catecholamines for improvement of congestive heart failure or peripheral circulatory failure accompanied with exceeded vasoconstriction.