Evaluation of Canine Cortical Bone Graft Remodeling     

ANN L. JOHNSON DVM  MS  Dipiomate ACVS    JO ANN C. EURELL DVM  PhD  DAVID J. SCHAEFFER PhD 《Veterinary surgery : VS》1992,21(4):293-298

A stable cortical bone fracture model was developed to evaluate the remodeling rate of cortical bone grafts. Samples of cortical bone were harvested with a trephine and press fit into predrilled holes in the femoral diaphyses of four live dogs. The percentages of new bone, unremodeled graft bone, porosity, forming bone surface area, and resorbing bone surface area were determined morphometrically and compared in cortical autografts, cortical allografts sterilized with 84% ethylene oxide (EO), and allografts sterilized with 12% EO. The host-graft interfaces healed without formation of fibrous tissue or cartilage, indicating a stable fracture surface. The amount of new bone formed in cortical autografts and allografts sterilized with 84% EO was significantly greater than the amount of new bone in allografts sterilized with 12% EO. There was no significant difference between the amounts of new bone formed in the allografts sterilized with 84% EO and the cortical autografts. No significant differences were detected in percentages of porosity or bone surface areas.  相似文献   

Chronological Appearance of Apoptosis in Bovine Embryos Reconstructed by Somatic Cell Nuclear Transfer from Quiescent Granulosa Cells     

JO Gjørret  J Wengle  P Maddox-Hyttel  WA King 《Reproduction in domestic animals》2005,40(3):210-216

Efficiency of cloning has remained low and in spite of attempts to improve this technology, many reconstructed embryos do not implant or are lost during early pregnancy. Chromosomal aberrations, deviant gene expression patterns and abnormal regulation of cell death may be involved in this increased early embryonic loss. Here, we investigate the chronological onset of both apoptotic changes in nuclear morphology and DNA degradation [detected by transferase-mediated dUTP nick-end labelling (TUNEL) reaction] in bovine two-cell- to blastocyst-stage embryos. Such embryos were generated either by reconstruction with nuclear transfer from quiescent granulosa cells or by regular in vitro embryo production. Nuclear condensation was observed from the two-cell stage and TUNEL labelling was observed from the six-cell stage in reconstructed embryos, whereas nuclear condensation was evident from the eight-cell stage and TUNEL labelling from the 13-cell stage in embryos derived in vitro. Furthermore, reconstructed embryos displayed elevated ratios of embryos containing apoptotic nuclei at pre-compaction stages and higher indices of apoptotic nuclei in morula and blastocyst stages when compared with in vitro-produced embryos.  相似文献   

The effects of exposure to water-soluble fractions of crude oil on selected histochemical parameters of the liver of Atlantic croaker, Micropogon undulatus L.     

JO ANN EURELL  W. E. HAENSLY 《Journal of fish diseases》1981,4(3):187-194

Abstract. Micropogon undulatus L. were sampled from Galveston Bay, Texas, and transported to the research laboratory. Groups of five fish were exposed to 5 and 10% dilutions of the water soluble fraction (WSF) of southern Louisiana crude oil for 1, 3, 7, 14 and 21 days. Selected histochemical parameters of liver sections from control and WSF-exposed fish were evaluated. Glycogen was reduced in amount while glucose-6-phosphate dehydrogenase, lipid and cholesterol were increased in liver sections of WSF-exposed fish. These observations support a hypothesis that exposure to petroleum hydrocarbons increases mixed-function oxidase activity. The alterations were more obvious in sections from fish exposed to the higher level of the WSF. The histochemical parameters appeared most altered in hepatocytes near afferent hepatic blood vessels. These hepatocytes were the first cells of the liver to contact the pollutants.  相似文献   

Analysis for total sulfite in foods by using rapid distillation followed by redox titration     

J W DeVries  H Ge  F J Ebert  J M Magnuson  M K Ogawa 《Journal of the Association of Official Analytical Chemists》1986,69(5):827-830

A rapid and accurate analysis for total sulfite as sulfur dioxide has been developed for foods and food products. The method, which combines a selective distillation cleanup procedure with the selective redox titration of sulfite ion by iodine, has been applied to a variety of foods and food products over a period of time with no significant interference encountered in any matrixes other than garlic and leeks. For the foods analyzed, the method typically shows a detection limit of 10 ppm, a relative standard deviation of 7.5% (compared with 10.4% for similar matrixes by the Monier-Williams method), and recoveries of 97.9 +/- 6.4%. Comparison of results for this method with those obtained using the Monier-Williams method showed a mean value for the distillation/titration method of 241 ppm compared with 242 ppm for the Monier-Williams method. A correlation of 0.991 and odds of a difference between methods of 10.7% (Student's paired t-test (1-alpha) X 100) were obtained for those matrixes where no interferences were encountered with either method.  相似文献   

Centres of Crop Diversity and/or Origin, Genetically Modified Crops and Implications for Plant Genetic Resources Conservation   总被引：1，自引：0，他引：1  

J. M. M. Engels  A. W. Ebert  I. Thormann  M. C. de Vicente 《Genetic Resources and Crop Evolution》2006,53(8):1675-1688

The concept of centres of crop diversity and/or origin of agriculture is briefly reviewed. The conservation status of crop genetic resources, either ex situ or in situ, cultivated or wild, has been assessed for species of the Central American and Mexican centre, demonstrating that that region is indeed one of the important centres of crop diversity for human kind. Furthermore, biotechnological developments with regard to the creation and spread of genetically modified crops have been analyzed. The likelihood of unintentional introgression of genetically modified traits into conventional seed lots, crops as well as into germplasm collections have been assessed. Related biosafety measures as well as the possible implications of intellectual property rights on transgenic crops and/or genes are being discussed vis-a-vis the possible implications they might have for germplasm management. The Central American crop genetic resources situation has been used as a “case study” to illustrate the potential impact of the spreading of GM varieties on the genetic diversity in genebanks and farmers’ fields and the need for effective and efficient conservation efforts. Conservation management strategies and practices are being proposed of mitigate the potential negative impact of GM crops on the conservation efforts.  相似文献   

The role of social groups in the persistence of learned fear     

Olsson A  Ebert JP  Banaji MR  Phelps EA 《Science (New York, N.Y.)》2005,309(5735):785-787

Classical fear conditioning investigates how animals learn to associate environmental stimuli with an aversive event. We examined how the mechanisms of fear conditioning apply when humans learn to associate social ingroup and outgroup members with a fearful event, with the goal of advancing our understanding of basic learning theory and social group interaction. Primates more readily associate stimuli from certain fear-relevant natural categories, such as snakes, with a negative outcome relative to stimuli from fear-irrelevant categories, such as birds. We assessed whether this bias in fear conditioning extends to social groups defined by race. Our results indicate that individuals from a racial group other than one's own are more readily associated with an aversive stimulus than individuals of one's own race, among both white and black Americans. This prepared fear response might be reduced by close, positive interracial contact.  相似文献   

Costing the ex situ conservation of plant genetic resources at AVRDC – The World Vegetable Center     

Pepijn Schreinemachers  Andreas W. Ebert  Mei-Huey Wu 《Genetic Resources and Crop Evolution》2014,61(4):757-773

AVRDC – The World Vegetable Center maintains the world’s largest international public collection of vegetable genetic resources at its headquarters in Taiwan. The ex situ conservation and dissemination of germplasm to researchers and breeders worldwide contributes to global food and nutrition security but also carries considerable costs. The objective of this study is to quantify these costs for the 12-month period from September 2011 to August 2012 using the Decision Support Tool developed by the International Food Policy Research Institute. The results show that the present value of capital assets is USD 1.99 million for the facilities and USD 0.48 million for the equipment. The total annual cost is USD 0.684 million, of which 74 % are labor costs. The average conservation and dissemination cost per accession is USD 10.08 per year. Seed regeneration, seed processing, characterization, and seed dissemination are the four most costly operations of the genebank. The storage itself only contributes 17 % of the cost. In comparison, the average cost per accession is USD 5.15 at ICARDA, USD 6.84 at CIMMYT, USD 8.62 at ICRISAT, USD 9.19 at IRRI, and USD 22.52 at CIAT (in 2012 US dollar values). High labor costs in Taiwan increase AVRDC’s average cost, but the fact that more vegetable species are self-pollinating and thus less labor intensive to regenerate than cross-pollinating species keeps the average costs in check. These results are important benchmarks for other genebanks.  相似文献