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排序方式: 共有590条查询结果,搜索用时 15 毫秒
31.
Nuclear transplantation in bovine embryos 总被引:9,自引:0,他引:9
J M Robl R Prather F Barnes W Eyestone D Northey B Gilligan N L First 《Journal of animal science》1987,64(2):642-647
This study was conducted to develop a method for transplanting nuclei in bovine embryos and to test the development of several stages of donor nuclei transplanted to enucleated pronuclear recipient embryos. Pronuclear embryos were centrifuged to reveal nuclei. Nuclei were removed without penetrating the plasma membrane as membrane-bound karyoplasts, and were inserted into enucleated zygotes by electrically induced cell fusion. The highest rate of fusion (79%) occurred in Zimmerman Cell Fusion medium at 100 V for 20 to 40 microseconds with the fusion membranes oriented parallel to the electrodes. The effect of nuclear transplantation on development was tested in pronuclear embryos in which nuclei were removed and reinserted and the embryos were then transferred to sheep oviducts for 5 d. Of the intact nuclear transplant embryos recovered, 5/29 (17%) developed to morulae or blastocysts compared with 11/30 (37%) of the non-manipulated embryos. Two nuclear transplant embryos were transferred to a recipient cow, and both developed to normal offspring. When nuclei from two-, four-, or eight-cell embryos were transplanted to pronuclear recipient embryos, no development was observed. 相似文献
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33.
Measurements of the equation of state of deuterium at the fluid insulator-metal transition 总被引:1,自引:0,他引:1
GW Collins Da Silva LB P Celliers DM Gold ME Foord RJ Wallace A Ng SV Weber KS Budil R Cauble 《Science (New York, N.Y.)》1998,281(5380):1178-1181
A high-intensity laser was used to shock-compress liquid deuterium to pressures from 22 to 340 gigapascals. In this regime deuterium is predicted to transform from an insulating molecular fluid to an atomic metallic fluid. Shock densities and pressures, determined by radiography, revealed an increase in compressibility near 100 gigapascals indicative of such a transition. Velocity interferometry measurements, obtained by reflecting a laser probe directly off the shock front in flight, demonstrated that deuterium shocked above 55 gigapascals has an electrical conductivity characteristic of a liquid metal and independently confirmed the radiography. 相似文献
34.
Tom turkey carcasses with partial green discolored livers (n = 191) or normal livers (n = 198) were examined for osteomyelitis and/or associated soft-tissue lesions. Seventy-nine turkeys with green discolored livers had osteomyelitis and/or associated soft-tissue lesions (41.4%), including 53 with just osteomyelitis (27.7%), while 112 (59.6%) had no osteomyelitis and/or soft-tissue lesions. Only five turkeys (2.5%) with normal livers had osteomyelitis. Discolored livers were significantly heavier, but carcasses with discolored livers weighed significantly less than carcasses with normal livers. Bacteria were isolated from 54 of 61 osteomyelitis lesions (88.5%); most frequently staphylococci (50.8%) followed by Escherichia coli (14.8%), Streptococcus sp. (13.1%), and occasional other organisms. Most associated soft-tissue lesions and livers were sterile (74.7%). These finding indicate that although turkey carcasses with green discolored livers are more likely to have osteomyelitis and/or associated soft-tissue lesions than turkey carcasses with normal livers, there is also an approximately equal chance they will not have these lesions. 相似文献
35.
Phorbol myristate acetate (PMA), which induces acute pulmonary injury in mammals, induced acute airsacculitis in turkeys after intra-airsac inoculation of 0.1 mg/kg. Grossly, air sacs contained multifocal to diffuse hemorrhage and edema at postinoculation hours (PIH) 3 and 6. Microscopically, there was multifocal congestion and small thrombocyte aggregates within small blood vessels by PIH 0.5, with a few vessels containing small numbers of marginating heterophils. By PIH 1.5, thrombocyte aggregates were larger and more numerous, and moderate numbers of heterophils were located perivascularly. Erythrocytes and proteinaceous fluid were in air sac interstitium. By PIH 3 and 6, hemorrhage and exudation of proteinaceous fluid had increased, in some instances severely distending the air sac. Ultrastructurally, changes resulting from PMA-induced injury were thrombocyte aggregation and degeneration, air sac epithelial cell vacuolation with separation of interdigitating cell processes, and endothelial cell vacuolar degeneration with loss of vascular integrity. Air sac lavage fluids had mildly increased total cell counts by PIH 1.5, but values returned to baseline by the end of the experiment, indicating lack of cell exudation into the air sac lumen. Circulating leukocyte changes included transient lymphopenia at PIH 3 and marked heterophilia at PIH 6. These results indicate that thrombocytes and/or heterophils are central to the pathogenesis of injury induced in air sacs by PMA and that the air sac responds differently to PMA than to pathogenic bacteria. 相似文献
36.
37.
Zafar TA Weaver CM Jones K Moore DR Barnes S 《Journal of agricultural and food chemistry》2004,52(10):2827-2831
The effect of inulin on isoflavone absorption and the effect of isoflavones and synergy with inulin on calcium absorption in rats was investigated. Rats (n = 48) were divided into three groups and fed inulin (50 mg/g), isoflavone (8 mg/g) or inulin + isoflavone (50 mg/g + 8 mg/g) diets for 21 days. After a 2-h fast, rats were given (45)Ca orally or intraperitoneally, together with 25 mg of calcium as calcium acetate. Blood and femurs were collected 4 days later. Sera were analyzed for isoflavones using HPLC-MS, femurs for (45)Ca by beta-scintillation counting, and total femoral calcium by atomic absorption spectroscopy. Both groups fed isoflavones had similar and significantly higher weight-adjusted total femoral calcium content compared to the inulin-fed group (p < 0.0001). (45)Ca absorption was significantly higher (p < 0.01) when isoflavones were added to the diet, and serum equol was significantly lower (p < 0.01) when inulin was added to the diet containing isoflavones. We conclude that isoflavones enhance calcium absorption, without synergy from inulin, and that inulin decreases equol production. 相似文献
38.
Simonne AH Smith M Weaver DB Vail T Barnes S Wei CI 《Journal of agricultural and food chemistry》2000,48(12):6061-6069
Isoflavones and carotenoids in four experimental genotypes and Hutcheson cultivar soybeans were evaluated as a function of processing treatments and maturity. Total isoflavone and carotenoid contents were affected by genotypes and maturity stages (p < 0.0001). Total isoflavones ranged from 472 microg/g (in NTCPR93-40) to 2280 microg/g (in Hutcheson). Lutein contents ranged from 895 (in NTCPR93-286) to 2119 (in Honey Brown), and beta-carotene ranged from 291 (in Hutcheson) to 491 (in NICPR92-40) microg/100 g. Mean total isoflavone retention percentages in immature Hutcheson soybeans were 46% (boiling), 53% (freezing), and 40% (freeze-drying). Mean retentions of lutein and beta-carotene, respectively, were 92 and 73% in frozen, 62 and 62% in boiled, and 34 and 27% in freeze-dried soybeans. Boiling caused a substantial increase in daidzin, genistin, and genistein. The results show that post-harvest changes in total isoflavones and carotenoids in soybeans are influenced by processing methods, but genotype has an effect on isoflavone and carotenoid profiles during seed development. 相似文献
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