Evaluation of left ventricular function with cardiac magnetic resonance imaging and echocardiography after administration of dobutamine and esmolol in healthy beagle dogs

Unlike echocardiography, cardiac magnetic resonance imaging (cardiac MRI) results in a near-exact assessment of cardiac structures and function. However, most veterinary studies have focused on dogs with normal cardiac function. We hypothesized that there would be significant differences in cardiac measurements between cardiac MRI and echocardiography when left ventricular (LV) function was abnormal. This study was undertaken to compare measurements of LV function produced by cardiac MRI and echocardiography in dogs whose LV function was altered by pharmacological agents. This study was conducted with six healthy beagle dogs. We increased left ventricular contractility by administration of dobutamine; we decreased cardiac contractility with esmolol. Stroke volume measurements were made by using both cardiac MRI and echocardiography under seven different conditions with general anesthesia: control, three doses of esmolol (100, 200, and 500 µg/kg/min), and three doses of dobutamine (10, 20, and 50 µg/kg/min). Experiments involving each condition were conducted at least 1 week apart. When LV contractility was normal, ejection fraction (EF) and stroke volume (SV), as measured by echocardiography and cardiac MRI, were not significantly different. However, when contractility was changed by pharmacological agents, EF and SV were overestimated by echocardiography, compared to MRI. Evaluation of cardiac function in patients treated with pharmacological agents should be conducted carefully because EF and SV measured by echocardiography can be overestimated, compared with EF and SV obtained by cardiac MRI.     

Are We Moving Back to the City? Examining Residential Mobility in the Washington,DC Metropolitan Area

This research assesses the extent to which there is evidence of population re‐centralization or back to the city moves by tracking the historical trend of household and income mobility in the Washington, DC metropolitan area. County‐to‐county migration data and four migration efficiency measures are used to investigate net flows of households and income in the region. The results show a nascent tendency of back to the city movement; however, the redistribution of households and income in the metropolitan area is more complex. While the region's core may be starting to gain households and income, there are still significant flows into the region's most distant suburbs. The results of this research have implications for transportation, housing, and economic development policy making in Washington, DC and other regions. The study also offers a unique example of how to study household and income redistribution within U.S. metropolitan areas.     

IMAGING ASSESSMENT OF THE MODIFIED DOUBLE CONTRAST BARIUM ENEMA USING CARBOXYMETHYLCELLULOSE ON RADIOGRAPHY AND ULTRASONOGRAPHY IN DOGS

A modified double contrast barium enema using carboxymethylcellulose was evaluated in beagle dogs and compared with dogs receiving a conventional barium enema. The experimental group was divided into three groups (1, 2, and 3) and given 30 ml/kg of different volume ratios of a barium vs. carboxymethylcellulose mixture. Each group underwent sonography following radiography. The volume ratio of one part barium to three parts carboxymethylcellulose was judged to be the optimal mixture, resulting in a general distribution of contrast and bowel radiolucency on radiographs and adequate postradiography sonography. The modified barium enema using carboxymethylcellulose is useful for assessing the general morphology and mucosal layers of the colon simultaneously on radiographs and ultrasonographs.     

Antiviral effect of dietary germanium biotite supplementation in pigs experimentally infected with porcine reproductive and respiratory syndrome virus

Germanium biotite (GB) is an aluminosilicate mineral containing 36 ppm germanium. The present study was conducted to better understand the effects of GB on immune responses in a mouse model, and to demonstrate the clearance effects of this mineral against Porcine reproductive and respiratory syndrome virus (PRRSV) in experimentally infected pigs as an initial step towards the development of a feed supplement that would promote immune activity and help prevent diseases. In the mouse model, dietary supplementation with GB enhanced concanavalin A (ConA)-induced lymphocyte proliferation and increased the percentage of CD3+CD8+ T lymphocytes. In pigs experimentally infected with PRRSV, viral titers in lungs and lymphoid tissues from the GB-fed group were significantly decreased compared to those of the control group 12 days post-infection. Corresponding histopathological analyses demonstrated that GB-fed pigs displayed less severe pathological changes associated with PRRSV infection compared to the control group, indicating that GB promotes PRRSV clearance. These antiviral effects in pigs may be related to the ability of GB to increase CD3+CD8+ T lymphocyte production observed in the mice. Hence, this mineral may be an effective feed supplement for increasing immune activity and preventing disease.     

Impact of rewilding,species introductions and climate change on the structure and function of the Yukon boreal forest ecosystem

Community and ecosystem changes are happening in the pristine boreal forest ecosystem of the Yukon for 2 reasons. First, climate change is affecting the abiotic environment (temperature, rainfall and growing season) and driving changes in plant productivity and predator–prey interactions. Second, simultaneously change is occurring because of mammal species reintroductions and rewilding. The key ecological question is the impact these faunal changes will have on trophic dynamics. Primary productivity in the boreal forest is increasing because of climatic warming, but plant species composition is unlikely to change significantly during the next 50–100 years. The 9–10‐year population cycle of snowshoe hares will persist but could be reduced in amplitude if winter weather increases predator hunting efficiency. Small rodents have increased in abundance because of increased vegetation growth. Arctic ground squirrels have disappeared from the forest because of increased predator hunting efficiency associated with shrub growth. Reintroductions have occurred for 2 reasons: human reintroductions of large ungulates and natural recolonization of mammals and birds extending their geographic ranges. The deliberate rewilding of wood bison (Bison bison) and elk (Cervus canadensis) has changed the trophic structure of this boreal ecosystem very little. The natural range expansion of mountain lions (Puma concolor), mule deer (Odocoileus hemionus) and American marten (Martes americana) should have few ecosystem effects. Understanding potential changes will require long‐term monitoring studies and experiments on a scale we rarely deem possible. Ecosystems affected by climate change, species reintroductions and human alteration of habitats cannot remain stable and changes will be critically dependent on food web interactions.     

水提与醇提对竹子中愈创木酚含量的影响

〔摘要〕目的优选竹子中有效成分愈创术酚的最佳提取溶媒〔方法将新鲜竹子砍成小段,再粉碎成粗粉,加水 或}o%乙醇回流提取,提取液采用高效液相法测定愈创术酚含量、色谱条件为:流动相0.50IcH,PO、的水溶液一乙睛 (78:22);固定相为C,、柱;流速1.0 mLJmin;柱温20 0C ;检测波长220 nm〔结果醇提法愈创术酚含量略高于水提法, 但无明显差异、结论水提法可以代替醇提法、     

The effect of fermented apple diet supplementation on the growth performance and meat quality in finishing pigs

The objective of the present study was to investigate the effect of fermented apple diet (FAD) supplementation on the growth performance and meat quality in finishing Berkshires. The FAD was made from dropped apple mixed with rice bran and barley bran. Until 81 ± 1 kg live weight at 133 ± 1 days, the animals were fed a growing diet, after which experimental samples were fixed at 0, 2, 4 and 6% FAD as C, T1, T2 and T3 in the finishing diets. Growth performance, ADG, ADFI and feed efficiency were improved in T1 than other groups. In carcass parameters, carcass weight was higher ( P  < 0.05) in T1 than in other groups. In meat quality, moisture and crude protein contents decreased ( P  < 0.05) by addition of FAD. pH₂₄ and WHC were higher ( P  < 0.05) in T1 than other groups. In sensory evaluation, marbling of fresh meat and tenderness, juiciness, flavor and overall acceptability of cooked meat were improved by the addition of FAD. According to the results of our experiment, FAD can be used for improvement of meat quality parameters.