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101.
102.
Cyclin E is a regulator of cyclin-dependent protein kinases (Cdks) and is involved in mediating the cell cycle transition from G1 to S phase. Here, we describe a novel function for cyclin E in the long term maintenance of checkpoint arrest in response to replication barriers. Exposure of cells to mitomycin C or UV irradiation, but not ionizing radiation, induces stabilization of cyclin E. Stabilization of cyclin E reduces the activity of Cdk2-cyclin A, resulting in a slowing of S phase progression and arrest. In addition, cyclin E is shown to be required for stabilization of Cdc6, which is required for activation of Chk1 and the replication checkpoint pathway. Furthermore, the stabilization of cyclin E in response to replication fork barriers depends on ATR, but not Nbs1 or Chk1. These results indicate that in addition to its well studied role in promoting cell cycle progression, cyclin E also has a role in regulating cell cycle arrest in response to DNA damage. 相似文献
103.
104.
Eugen F. Mesaros Jason P. BurkeJonathan D. Parrish Benjamin J. DuganAndrew V. Anzalone Thelma S. AngelesMark S. Albom Lisa D. AimoneMatthew R. Quail Weihua WanLihui Lu Zeqi HuangMark A. Ator Bruce A. RuggeriMangeng Cheng Gregory R. Ott Bruce D. Dorsey 《Bioorganic & medicinal chemistry letters》2011,21(6):1900
105.
Preparation of cross-linked carboxymethyl chitosan for repairing sciatic nerve injury in rats 总被引:1,自引:0,他引:1
A successful nerve regeneration process was achieved with nerve repair tubes made up of 1-ethyl-3(3-dimethylaminopropyl) carbodiimide
hydrochloride (EDC) cross-linked carboxymethyl chitosan (CM-chitosan) with improved biodegradability. Chitosan has a very
slow degradation rate, while the EDC cross-linked CM-chitosan tubes degraded to 30% of original weight during 8 weeks of incubation
in lysozyme solution. In vitro cell culture indicated that the CM-chitosan films presented no cytotoxicity to Schwann cells.
From in vivo studies using a 10 mm rat sciatic nerve defect model investigated by histomorphometry analysis, the average diameter
of the fibers and the average thickness of myelin sheath in the CM-chitosan tubes were 3.7 ± 0.33 and 0.33 ± 0.04 μm, respectively,
which demonstrated equivalence to nerve autografts (the current “gold” standard); furthermore, the average fiber density in
the CM-chitosan tubes was 20.5 × 103/mm2, which was similar to that of autografts (21 × 103/mm2) and significantly higher than that of common chitosan tubes (15.3 × 103/mm2). 相似文献
106.
Humoral antibody response to sheep red blood cells and cellular immune response to bovine serum albumin were studied in Mycoplasma pulmonis infected, adult, male Sprague-Dawley rats. The hemagglutinating antibody response to sheep red blood cells was evaluated at 0, 3, 5, 7, 14, 21 and 28 days postinfection. Antibody titers during all days postinfection were depressed significantly (p less than 0.05) in infected rats as compared to noninfected controls. Cellular immune responses were evaluated by a delayed hypersensitivity response. Rats were sensitized at 0, 3, 5, 7, 14, 21 or 28 days postinfection with bovine serum albumin and challenged with heat aggregated bovine serum albumin 7 days later. Cell-mediated immune responses in infected rats were not significantly different at any point from controls. These results indicate that M. pulmonis infection in rats suppresses the humoral antibody response to sheep red blood cells, but not the cellular immune response to bovine serum albumin. 相似文献
107.
The variance component ratio delta = (theta 1 + d theta 2)/theta 3 is of interest in many fields of application. This paper proposes and compares two methods for constructing confidence intervals on delta. The better method is compared with a method proposed by Graybill and Wang (1979, Journal of the American Statistical Association 74, 368-374) for the special problem of constructing an interval on sigma 2E/(sigma 2A + sigma 2B + sigma 2E) in a two-fold nested design. An example concerning a heritability study is provided. 相似文献
108.
109.
Jianping Zhang Houyuan Lu Wanfa Gu Naiqin Wu Kunshu Zhou Yayi Hu Yingjun Xin Can Wang 《PloS one》2012,7(12)
The Peiligang Culture (9000-7000 cal. yr BP) in the Middle Yellow River region, North China, has long been considered representative of millet farming. It is still unclear, however, if broomcorn millet or foxtail millet was the first species domesticated during the Peiligang Culture. Furthermore, it is also unknown whether millet was cultivated singly or together with rice at the same period. In this study, phytolith analysis of samples from the Tanghu archaeological site reveals early crop information in the Middle Yellow River region, China. Our results show that broomcorn millet was the early dry farming species in the Peiligang Culture at 7800 cal. yr BP, while rice cultivation took place from 7800 to 4500 cal. yr BP. Our data provide new evidence of broomcorn millet and rice mixed farming at 7800 cal. yr BP in the Middle Yellow River region, which has implications for understanding the domestication process of the two crops, and the formation and continuance of the Ancient Yellow River Civilization. 相似文献
110.