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951.
Kaushal S La Russa VF Hall ER Gartner S Kim JH Perera LP Yu Z Kessler SW Mosca JD 《Journal of biomedical science》1997,4(2-3):61-68
In order to develop a convenient small-animal model that can support the differentiation of human bone-marrow-derived CD34+ cells, we transplanted SCID mice with an immortalized human stromal cell line, Lof(11–10). The Lof(11–10) cell line has been characterized to produce human cytokines capable of supporting primitive human hematopoietic cell proliferation in vitro. Intraperitoneal injection of Lof(11–10) cells into irradiated SCID mice by itself resulted in a dose-dependent survival of the mice from lethal irradiation. The radioprotective survival was reflected by an increase in the growth and number of mouse bone-marrow-derived committed hematopoietic progenitors. The Lof(11–10) cells localized to the spleen, but not to the bone marrow of these animals and resulted in detectable levels of circulating human IL-6 in their plasma. Secondary intravenous injections of either human or simian CD34+ cells into the Lof(11–10)-transplanted SCID mice resulted in engraftment of injected cells within the bone marrow of these mice. The utility of this small-animal model that allows the growth and differentiation of human CD34+ cells and its potential use in clinical gene therapy protocols are discussed. 相似文献
952.
953.
Human gastric cancer MKN-45 cells were transfected with pULB 3238,a plasmid carrying MVMp MS-1 gene with its original P4 promoter replaced by the glucocorticoid inducible promoter MMTV-LTR.After the integration and expression of NS-1 gene,some of the transfectants died,while others remained alive,but the growth features of survived cells were changed.For further study on the antineoplastic function of parvoviral NS-1 protein in vivo,transgenic mice carrying NS-1 genes were established by conventional method.Among 4 founders,one of them was found to be able to transmit the transgene to around 50% of their offsprings.RT-PCR was performed to indicate the expression of NS-1 gene in transgenic mice and its mRNA appeared in a variety of tissues.The expression of integrated NS-1 gene may correlate with the decreased incidence of tumor induced in vivo by chemical carcinogens. 相似文献
954.
用免疫组织化学S-P方法,检测了40例低分化鼻咽癌、30例鼻咽癌克隆细胞裸鼠移植瘤、10例慢性鼻咽炎及8例人胚鼻咽上皮组织石蜡包埋切片中抗凋亡基因bcl-2癌蛋白的表达;并进一步检测了鼻咽癌克隆株在裸鼠体内演进中bcl-2癌蛋白的表达以及与淋巴结转移之间的关系。结果表明:鼻咽癌及其裸鼠移植瘤组织中bcl-2癌蛋白的表达率分别为62.5%和70%,慢性鼻咽炎中bcl-2癌蛋白的表达率为10%,人胚鼻咽上皮组织中不表达bcl-2癌蛋白,鼻咽癌及其裸鼠移植瘤组织中bcl-2癌蛋白的表达率明显高于慢性鼻咽炎组织中(P<0.01);鼻咽癌克隆株演进中癌细胞bcl-2癌蛋白的表达不断升高,其淋巴结转移率亦不断升高。提示:抗凋亡基因bcl-2癌蛋白的表达可能和鼻咽癌的发生、演进及转移能力密切相关 相似文献
955.
Opportunistic Properties of Nosema algerae (Microspora), a Mosquito Parasite, in Immunocompromised Mice 总被引:1,自引:0,他引:1
THOMAS TRAMMER FRANK DOMBROWSKI MARTINA DOEHRING WALTER A. MAIER HANNS M. SEITZ 《The Journal of eukaryotic microbiology》1997,44(3):258-262
ABSTRACT. In the last ten years microspordia have been recognized as opportunistic pathogens in AIDS patients. The sources of infection and the mechanisms of transmission of these organisms in humans are mostly uncertain. Transmission of invertebrte microsporidia to mammals is normally considered impossible, temperature being a limiting factor for development. Mice treated with cortisone acetate and with cyclosporin A, respectively, as well as athymic mice were injected intravenously, intranasally, perorally and subcutaneously with spores of Nosema algerae , a microsporidian species of culicine mosquitoes. No infection could be detected in tissue samples of cortisone acetate and cyclosporin A treated mice. However, the experimental inoculation of spores into the tail and foot of athymic mice caused severe infection in skeletal muscles and the connective tissue. In some tails, nerve tissue and bone marrow were also infected. Vegetative stages and spores were seen in direct contact to host cell cytoplasma. For the first time the prolonged and progressive development of an invertebrate microsporidium in a mammalian host is shown. The possibility of invertebrate microsporidia as a source of human microsporidiosis should now be taken into consideration. 相似文献
956.
LAO Weide LIU WeiCHENG Guoxiang XU Shaofu CHENG Yong 《中国科学:生命科学英文版》1996,39(6):592-599
Two αs1-casein/chloramphenicol acetyltransferase (CAT) gene constructs overlapping by 3.0kb were constructed and co-injected into murine zygotes. In 9 of 10 lines of transgenic mice obtained, based on analysis of structure and expression of the transgene, accurate extrachromosomal homologous recombination (ECR) between the two overlapping DNA fragments was found. Different levels of CAT activity were detected in milk from these lines. The highest CAT activity was about 25-50μg/mL milk. In some mice. CAT activity was found in salvia gland, thymus and spleen extracts. The high frequency and accuracy of ECR reported here will be applicable in the experimental manipulation for generation of relatively large transgene. 相似文献
957.
Two αs1-casein/chloramphenicol acetyltransferase (CAT) gene constructs overlapping by 3.0kb were constructed and co-injected into murine zygotes. In 9 of 10 lines of transgenic mice obtained, based on analysis of structure and expression of the transgene, accurate extrachromosomal homologous recombination (ECR) between the two overlapping DNA fragments was found. Different levels of CAT activity were detected in milk from these lines. The highest CAT activity was about 25-50μg/mL milk. In some mice. CAT activity was found in salvia gland, thymus and spleen extracts. The high frequency and accuracy of ECR reported here will be applicable in the experimental manipulation for generation of relatively large transgene. 相似文献
958.
Noriyuki Nishida Shigeru Katamine Kazuto Shigematsu Akira Nakatani Nobuhiro Sakamoto Sumitaka Hasegawa Ryota Nakaoke Ryuichiro Atarashi Yasufumi Kataoka Tsutomu Miyamoto 《Cellular and molecular neurobiology》1997,17(5):537-545
1. The cellular prion protein, designated PrPc, is a key molecule in the prion diseases but its physiological function remains unknown. To elucidate whether PrPc plays some role in the central nervous system, we established a line of mice in which the PrP gene had been disrupted and subsequently conducted long-term observations.2. Performance in latent learning and passive avoidance was evaluated using water-finding and step-through tests, respectively.3. PrP
–/– mice showed impaired performance in the water-finding test, indicating a disturbance in latent learning, at 23 weeks of age. In the step-through test, although the PrP
–/– mice showed normal learning ability and short-term memory retention, they evidenced a significant disturbance in long-term memory retention.4. These results indicate that PrPc is needed for certain types of learning and memory and that the loss of function of this protein may contribute to the pathogenesis of prion diseases. 相似文献
959.
ES细胞系统与基因定位致变相结合,进行基因敲除(knockout)已成为研究基因在生物体内功能的重要手段。在ES细胞系的建立、外源基因导入ES细胞、种系嵌合鼠的获得等三个重要环节中,种系嵌合鼠的获得是最关键的一环。由于ES细胞系统技术复杂、实验条件要求很高,尽管国际上已报导了上百例的基因敲除(knockout)实验,但是到目前为止,我国还无一例在国内条件下获得种系嵌合鼠的正式报道。本研究对影响种系嵌合鼠获得的两种因素(饲养层细胞、受体胚胎种类)进行了比较研究,成功地获得了种系嵌合鼠。将HM1细胞在STO或MEF培养层上培养至2133代,注射到不同小鼠的囊胚里,经过恢复培养,移植到假孕的昆明白雌鼠子宫内。由于HM1细胞来源于粟色的的129品系,而胚胎供体鼠的毛色为黑或白色,仔鼠出生一周后即可辨别是否为毛色嵌合鼠。用成年嵌合鼠与其受体胚胎相同品系的小鼠交配,进行种系嵌合鼠鉴定。曾有报导:STO培养层会导致ES细胞发生核变。我们改用MEF培养层,获得嵌合鼠的比率高达48.6%(Table1)。不同小鼠胚胎之间存在差异,C57BL/6J、ICR和昆明白三者提供的受体胚胎产生嵌合鼠的比率分别为71.4%、55% 相似文献
960.
Ovular morphology was examined ultrastructurally inPseudotsuga menziesii to determine the effects of the ovule on pollen development. Vesicles containing lipid-like substances traverse cell walls
of the inner epidemis of the integument and release their contents at the integument surface to form the integumentary membrane.
A major aqueous secretion from the integument into the micropylar canal is proposed to occur by the movement of the integumentary
membrane and its invaginations towards the center of the micropylar canal. The cellular degeneration of the nucellar apex
results from the breakdown of vacuoles. After this degeneration, electron-dense substances move from the prothallial cells
of the female gametophyte towards the nucellus, and many morphological changes in the nucellus, prothallial cells, and micropylar
canal take place simultaneously. We interpret these changes to result from another major secretion from the prothallial cells.
Egg cytoplasm appears to disorganize for a short time. Simultaneously, substantial amounts of electron dense-substances in
the prothallial cells and lipid-like substances in surface cell walls of the female gametophyte move towards the nucellus
as components of the third major secretion. 相似文献