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51.
R B Dickson M D Johnson M Bano E Shi J Kurebayashi B Ziff I Martinez-Lacaci L T Amundadottir M E Lippman 《The Journal of steroid biochemistry and molecular biology》1992,43(1-3):69-78
While endocrine steroid hormones have been known for many years to regulate normal and malignant mammary epithelium, recent studies have led to an appreciation of polypeptide growth factors as locally-acting autocrine and paracrine effectors. In the current article we summarize what is known about growth factor regulation and action in the normal mammary gland and about perturbations of the steroid-growth factor interplay as cancer progresses. A major theme is that oncogenic activation modulates both regulation of production and function of growth factors in the mammary gland. 相似文献
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53.
流行性出血热地鼠肾细胞灭活疫苗人体试用细胞免疫反应观察 总被引:2,自引:0,他引:2
观察了20位志愿者在接种试验性流行性出血热(EHF)地鼠肾细胞(GHKC)双价灭活疫苗后的细胞免疫反应,并以其体液免疫反应作对照观察。用淋巴细胞转化试验测定细胞免疫水平。结果首针疫苗接种后42天和56天,特异性刺激指数(SSI)和非特异性刺激指数(NSI)均较免疫前显著增高(P_(SSI)<0.001;P_(NSI)<0.02),免疫后SSI累计阳转率为100%,NSI累计阳转率为60%,免疫后6个月二者均降低至正常水平。免疫后56天测定抗体,荧光抗体阳转率为100%;微量感染性中和试验表明,针对家鼠型病毒L99株中和抗体阳转率为95%,而针对野鼠型病毒JR株阳转率为65%。 相似文献
54.
55.
茭白黑粉菌在茭白植株内形态发育的初步研究 总被引:15,自引:0,他引:15
茭白黑粉菌的菌丝体多年生,越冬期宿存于茭白地下茎中,翌年春天入侵由地下茎芽体形成的植株。菌丝具隔膜,分枝,细胞双核,在寄主细胞间隙并入侵细胞中生长,无吸器;受菌丝侵染的茭白地上茎薄壁细胞分裂增多,体积加大,并高度液泡化,使茎膨大。部分菌丝在茭白茎膨大后期菌丝壁胶化,原生质收缩成团,生成厚壁,形成冬孢子。 相似文献
56.
两种锦鸡和环颈雉线粒体DNA(mtDNA)的比较研究 总被引:15,自引:3,他引:12
本文以10种限制性内切酶分析雉科中环颈雉,红腹锦鸡和白腹锦鸡线粒体DNA(mtDNA)。雉属与锦鸡属之间的遗传距离P为0.076(0.067-0.085),红腹锦鸡与白腹锦鸡的P为0.012。推算雉属和锦鸡属的分化大约发生在3.8×10[6]年以前,红腹锦鸡与白腹锦鸡的分化大约在6×10[5]年以前。这些结果表明:1.在雉科系统发生中,雉属与锦鸡属是近缘的属;2.红腹锦鸡和白腹锦鸡的分化较晚,关系密切,可能只是两个亚种。 相似文献
57.
The long-distance migration of Nilaparvata lugens (Stål) (Delphacidae) in China: radar observations of mass return flight in the autumn 总被引:1,自引:0,他引:1
J. R. RILEY CHENG XIA-NIAN ZHANG XIAO-XI D. R. REYNOLDS XU GUO-MIN A. D. SMITH CHENG JI-YI BAO AI-DONG ZHAI BAO-PING 《Ecological Entomology》1991,16(4):471-489
Abstract.
- 1 A case study is presented of the autumn migration of the brown planthopper, Nilaparvata lugens (Stål), in the area of Nanjing in the People's Republic of China. The study was made using a high frequency (8 mm wavelength) radar and a net suspended from a kytoon.
- 2 The observations confirmed that long-distance return migrations occur in China in mid and late September, with N.lugens being carried on the prevailing north-easterly wind towards the autumn infestation and overwintering areas of the species.
- 3 After mass take-off in the late afternoon or at dusk, the migrants flew for several hours during the evening, often in a dense layer which formed at heights between about 400 and 1000m above ground. These layers often had well-defined ceilings corresponding to an air temperature of about 16°C. The migration height was above the top of the surface temperature inversion, i.e. the migrants did not fly at the height of the warmest air.
- 4 The dense layer concentrations overflying the radar were backtracked to source areas up to 240 km away in the north-east of Jiangsu Province. Planthoppers observed emigrating from the Nanjing area would reach areas in south Anhui Province or north Jiangxi Province if they flew for 12 h.
- 5 There was a second period of mass take-off at dawn. Insect layers sometimes formed but did not last longer than 1–2h.
- 6 The present results were strikingly different from those previously observed in the dry season in the Philippines, where migratory flight durations were largely confined to periods of about 30min at dusk and dawn.
- 7 Our observations are discussed in relation to the equator-wards return migrations undertaken in autumn by other insect species, and the importance of these migrations for the maintenance of long-flying genotypes in the overwintering populations is considered.
58.
蟾蜍血液淋巴细胞姐妹染色单体互换及细胞周期动力学研究 总被引:1,自引:1,他引:0
本文对中华大蟾蜍Bufo bufo gargarizans血液淋巴细胞在植物血球凝集素(PHA)刺激条件下的细胞周期动力学及丝裂霉素C(MMC)诱发姐妹染色单体互换(SCE)的敏感性进行了研究。用姐妹染色单体差别染色方法确定细胞的分裂次数。实验结果表明,中华大蟾蜍血液淋巴细胞在体外培养2天后出现第二次分裂细胞,3天后达峰值(占分裂细胞中期相的38.9%),此后,其百分比逐日下降,培养后4天出现第三次分裂细胞,第5天出现第四次分裂细胞。Brdu浓度在8—24μg/ml范围内对SCE本底无影响。6ng/ml MMC所诱发的SCEs比对照组高3倍以上,说明中华大蟾蜍对MMC的诱变作用相当敏感。 相似文献
59.
Samples of soybean plants with virus-like symptoms were collected from several locations in the People's Republic of China in 1981. These samples were used to prepare inocula for mechanical inoculation to soybean. Twenty-one virus cultures were obtained, the identities of which were determined by serology, symptomatology and host range. Sixteen cultures contained only soybean mosaic virus, four of which were more pathogenic than any previously studied; one culture contained only tobacco ringspot virus, another only southern bean mosaic virus, and three other cultures mixed infections of soybean mosaic and southern bean mosaic viruses. This is the first report of the occurrence of tobacco ringspot virus and southern bean mosaic virus in soybean in the People's Republic of China. 相似文献
60.
棉酚对几种动物精子ATP酶抑制作用的比较研究 总被引:1,自引:0,他引:1
本文比较了棉酚对几种动物精子ATP酶的抑制作用。实验所测为精子细胞的总ATP酶活力;采用的棉酚浓度为10μM至80μM。20μM时精子酶的相对活力为海胆7604%,大鼠74%,家兔51.6%;40μM时酶的相对活力百分数下降至海胆52.5,大鼠35和家兔29.7;达80μM时酶的相对活力进一步下降至海胆26.7,而大鼠及家兔仅余13.2。结果表明(1)棉酚对精于ATP酶的抑制作用是依赖浓度的变化;(2)各种动物精子ATP酶活力的下降情况显示,大鼠及家兔(哺乳动物)精子ATP酶对棉酚的敏感性比海胆(无脊椎动物)要高些。这种差异性可能对棉酚在临床上的应用具有一定的参考价值。 相似文献