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11.
DNaseⅠ超敏感位点的研究能够发现潜在的调控基因转录活化的位点,比较正常人外周血有核细胞,淋巴瘤细胞株P3HR1和人鼻咽癌低分化磷癌细胞株HOnE1和HNE2中Ha-ras-1瘤基因的DNaseⅠ超敏感位点发现,只有HONE1和HNE2细胞基因组中存在一个DNaseⅠ超敏感位点,位于第一个外显子上游0.37kb处,上述结果提示正常白细胞和P3HR1细胞中Ha-ras-1基因处于失活状态,而在鼻咽癌细胞基因组中则处于活化状态,它的活化可能与0.37kb处的DNA序列有密切的关系。 相似文献
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Parthenogenetic sporophytes were obtained from three strains of Laminaria japonica Areschoug. These sporophytes grew to maturity in the sea, producine spores that all grew into female gametophytes. These female gametophytes gave rise to another generation of parthenogenetic sporophytes during the next year, so that by the year 1990 parthenogenetic sporophytes had been cultivated for 12, 9, and 7 generations, respectively, for the three strains. When female gametophytes from parthenogenetic sporophytes were combined with normal male gametophytes, normal sporophytes that reproduced and gave rise to both female and male gametophytes were obtained. The parthenogenetic sporophytes were shorter and narrower than the normal sporophytes of the same strain. Chromosome counts on mature sporophytes showed that normal sporophytes (from fertilized eggs) were diploid (2n = approximately 40) and that the spores they produced were haploid (n = approximately 20), while nuclei from both somatic and sporangial cells in parthenogenetic sporophytes were haploid. All gametophytes were haploid. Young sporophytes derived from cultures with both female and male gametophytes were diploid, while young, sporophytes obtained from female gametophytes from parthenogenetic sporophytes had haploid, diploid, or polyploidy chromosome numbers. Polyploidy was associated with abnormal cell shapes. The presence of haploid parthenogenetic sporophytes should be use in breeding kelp strains with useful characteristics, since the sporophyte phenotype is expressed from a haploid genotype which can be more readily selected. 相似文献
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Yangyang Xu Jie Zhang Fei Gao Wenna Cheng Ye Zhang Chuanmei Wei Shuping Zhang Xinfu Gao 《Journal of cellular and molecular medicine》2023,27(12):1653-1663
High-mobility group box1 (HMGB1) induces inflammatory injury, and emerging reports suggest that it is critical for brain ischemia reperfusion. Engeletin, a natural Smilax glabra rhizomilax derivative, is reported to possess anti-inflammatory activity. Herein, we examined the mechanism of engeletin-mediated neuroprotection in rats having transient middle cerebral artery occlusion (tMCAO) against cerebral ischemia reperfusion injury. Male SD rats were induced using a 1.5 h tMCAO, following by reperfusion for 22.5 h. Engeletin (15, 30 or 60 mg/kg) was intravenously administered immediately following 0.5 h of ischemia. Based on our results, engeletin, in a dose-dependent fashion, reduced neurological deficits, infarct size, histopathological alterations, brain edema and inflammatory factors, namely, circulating IL-1β, TNF-α, IL-6 and IFN-γ. Furthermore, engeletin treatment markedly reduced neuronal apoptosis, which, in turn, elevated Bcl-2 protein levels, while suppressing Bax and Cleaved Caspase-3 protein levels. Meanwhile, engeletin significantly reduces overall expressions of HMGB1, TLR4, and NF-κB and attenuated nuclear transfer of nuclear factor kappa B (NF-κB) p65 in ischemic cortical tissue. In conclusion, engeletin strongly prevents focal cerebral ischemia via suppression of the HMGB1/TLR4/NF-κB inflammatory network. 相似文献
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应用清栓酶治疗不同病期脑梗塞38例,总有效率86.7%,发病后治疗时间越早,疗效越好。治疗前病人均有不同程度的TXA2升高,PGI2下降,急性期更为明显,治疗后TXA2下降,PGI2上升,使失调的PGI2-TXA2平衡得以恢复 相似文献
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Norman S. Wolf Philip E. Penn DeZhao Jiang Rui Gao Fei William R. Pendergrass 《Experimental cell research》1995,217(2)
In male mice of a long-lived hybrid strain (B6D2F1), long-term 40% caloric restriction (CR) extended both mean and maximum life spans by 36 and 20%, respectively, over that of ad libitum fed (AL) controls. Measurements of entry into S-phase were made in vivo of six different cell types in five different organs using 2-week exposures to BrdU. The labeling index (L.I.) in all organs studied was lower in young CR mice than in young AL fed mice. In most cases, the L.I. in AL mice fell to the levels of that in the CR mice by 13 months of age, and the two groups then remained so through old age. However, when the L.I. was measured in old CR mice which had been placed on the AL diet for a period of 4 weeks (this was termed refeeding (RF)), it was found to be above that of similar age AL or CR mice and almost at the level of young AL mice. This was still true, but to a lesser degree, in a repeat study using an 8-week period of RF. In a separate but parallel in vitro study (companion paper, this volume), the superiority of CR over AL for retention of cellular replication capacity was confirmed by clone size distribution measurements made in several cell types in mice of several age groups. These results indicate that: (1) the rate of cell replication in AL diet mice diminishes greatly by early middle age in all organ sites studied and then plateaus or declines much more slowly; (2) CR broadly preserves in vivo cellular replicative capacity but often requires the energy levels provided by a switch to AL feeding to demonstrate this late in life; (3) accordingly, the replicative deficit in AL fed mice appears to be cumulative and is significant only in old age. The mechanism(s) involved is yet to be discovered but may be related to, or even the same as, that which extends life spans in CR animals. Correspondingly, and with corroborative data from our in vitro companion study, (W. R. Pendergrass et al., 1995. Exp. Cell. Res. 217, 309-316), we suggest that cell populations sustain an accrual of biochemical damage or physiological alterations which increasingly limit their replicative capacity as the animal ages, and that CR reduces the accrual of this damage. 相似文献
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In vitro 5-day cultures of naive spleen cells with viable Listeria monocytogenes (VLM), but not heat-killed L. monocytogenes, induced CD4+ T cells that produced IFN-γ upon secondary antigen stimulation. The VLM-induced Listeria-specific T cells produced IFN-γ but lacked expression of IL-2 and IL-4. To study the role of IFN-γ in the induction of the IFN-γ-producing T cells, we added anti-IFN-γ mAb to the primary culture and analyzed IFN-γ production upon secondary antigen stimulation. Addition of anti-IFN-γ mAb to the culture suppressed generation of IFN-γ-producing CD4+ T cells, suggesting that IFN-γ is important in the induction of IFN-γ-producing CD4+ T cells. Furthermore, our results showed that depletion of NK cells from spleen cells by anti-asialo GM1 antibody plus complement before culture enhanced induction of IFN-γ-producing CD4+ T cells. Although NK cells are known to produce IFN-γ, the results indicate that NK cell-derived IFN-γ may not be important in induction of the Listeria-specific IFN-γ-producing CD4+ T cells in the culture system. In addition, we demonstrated that IFN-γ expression was high in CD4+ T cells from cultures of spleen cells with VLM at the primary culture level. These results suggest that IFN-γ derived from T cells may enhance production of IFN-γ by CD4+ T cells, while NK cells rather suppress the induction of IFN-γ-producing CD4+ T cells. 相似文献
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东亚大都市学生头型的比较研究 总被引:2,自引:1,他引:1
为了研讨居住区域的气候条件和社会经济环境对头型的影响,采用国际通用的人体测量法,调查测量了东亚三个国家四个集团3472名6-17岁学生的头长和头宽,经统计学处理求得其平均值、头指数,回归方程,并作性差和地区差检验,其结果表明:中国大连学生为特圆头型,菲律宾马尼拉学生为圆头型,地理位置在大连和马尼拉之间的日本东京的学生的头型也位于二者之间,生活富裕集团的头长和头宽明显大于生活贫穷集团的学生,但头型二 相似文献