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Y S Lee  Y Yajima  M Nonoyama 《Virology》1977,81(1):17-24
Virus DNA (RS virus DNA) was directly isolated from Raji cells superinfected with Epstein-Barr virus derived from P3HR-1 cells and compared with original superinfecting virus DNA from P3HR-1 cells (HR-1 virus DNA) in agarose-gel electrophoresis after digestion with various restriction enzymes. EcoR-1 digestion of RS virus DNA produced 15 fragments identical to those from HR-1 virus DNA. However, two fragments, EcoR1 No. 6 (10 × 106 daltons) and EcoR1 No. 11 (4.6 × 106 daltons), observed in HR-1 virus DNA were not detected in RS virus DNA from superinfected Raji cells. In addition, the EcoR1 No. 4 (13.5 × 106 daltons) fragment of RS virus DNA showed a molar ratio of 2 whereas HR-1 virus DNA produced the same fragment with a molar ratio of 1. Electrophoresis patterns of virus DNA digested with Hind III, Bam H-I, Hpa I, and Sal I were also examined. In general, both types of virus DNA produced similar patterns after gel electrophoresis, with minor differences in molar ratios after being treated with the restriction enzymes suggesting that RS virus DNA obtained by superinfection of Raji cells is basically identical to HR-1 virus DNA but may contain a population of DNA a little more heterogenous than HR-1 virus DNA.  相似文献
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The histones of 75 human tissues were examined by polyacrylamide gel electrophoresis. A new minor Hl histone called Hlh was found in every case and is proposed to be characteristic of human tissue. The previously described minor Hl histone, Hla, was not detectable in lymph nodes or spleen. The amount of Hlh and Hla relative to the principle Hl band varied from tissue to tissue. As compared to the normal tissue, the amount of Hlh was increased and the Hla decreased in cancers. The sole exception was one hepatocellular carcinoma in which the Hla was increased in the tumor. In two cases of carcinoma of the breast the Hla was decreased to an almost undetectable level. No changes in the other histones were found. These observations may be useful in the diagnosis and prognosis of human malignant disease as well as in forensic medicine.  相似文献
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Chinese hamster cells, Don line, were treated with concanavalin A (ConA), calcium ionophore A23187 (A23187), colchicine, sodium fluoride (NaF), 6-thiopurine, dibutyryl cyclic AMP (db-cAMP), and other nucleotides, alone or in combination. A23187 itself did not induce endoreduplication but did so in combination with ConA. NaF could induce endoreduplication and the combination of NaF and ConA showed a synergistic effect. db-cAMP suppressed the inducing activity of ConA. The findings that various chemicals are inducers of endoreduplication and that synergistic effects appear on combined treatments suggest that various mechanisms of induction of endoreduplication may exist. The chemical nature of the inducers and the suppressor, db-cAMP, implies that blocking of the phosphorylation of some cellular components may be involved as a main mechanism. Analysis of the endoreduplication cell cycle indicated that cells treated with reagents in S require a longer cell cycle than those treated in G2 and that the length of the lag period between induction treatment and the initiation of S, the length of S, and the length of G2 war variable. The inducers, induction mechanisms, and the cell cycle of endoreduplication seem to vary; however, the essence of endoreduplication is the omission of mitotic events by connecting S and G1.  相似文献
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Macrophages can bind and engulf a variety of particles in the absence of specific opsonins. Polystyrene-type microspheres are often employed to quantitate opsonin-independent phagocytic activities of macrophages in vitro. Reliable measurement of this cell function, however, requires the ability of the investigator to distinguish between particles that are merely attached to the cell surface and those that are actually internalized. We have developed a simple, rapid, and reproducible method for quantitating phagocytosis using polystyrene microspheres and adherent alveolar macrophages. Basically, particles associated with macrophages after a given incubation time are microscopically quantitated on a cell-by-cell basis before and after toluene dissolution of external particles. Particle/macrophage values obtained after toluene treatment exclusively index phagocytosis.  相似文献
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Summary During the flight of Spacelab-1 a series of vestibular experiments was performed on the crew by a group of European investigators. Control experiments were carried out on the same subjects pre- and postflight. The tests included caloric stimulation of the ears, threshold measurements of response to linear acceleration, motion sickness provocative stimuli, vestibulo-ocular reflexes during linear and angular stimulation, estimation of the subjective vertical (luminous line measurements) and static ocular counterrotation at various tilt angles. The caloric experiment proved the existence of a non thermoconvective mechanism of caloric nystagmus in space. Most of the other test results point to a greater dependence on visual and somatosensory than on otolith cues in the microgravity environment. Some results, in particular the raised threshold to perception of linear acceleration in flight and the temporary reduction of ocular counterrotation at lateral tilts postflight, suggest a decreased gain of the otolith system as a possible effect of space vestibular adaptationSupported by a grant from the German Department of Research and Technology no. 01 QV 017 SL 1  相似文献
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人前列腺特异抗原(PSA)基因特异地在前列腺上皮细胞中表达。且受雄激素调节。其雄激素应答元件(ARE)位于-170附近。为确定雄激素对该基因的诱导作用是否受ARE上游序列的影响,把PSA启动子区的不同长度的DNA片段与无启动子的报告基因CAT相连,然后与雄激素受体表达质粒一起共传染人前列腺肿瘤细胞PC-3。结果表明ARE上游RF36(-406~─371)和RF15(─340~─326)两个序列可促进雄激素对PSA基因的诱导作用。这些序列可与PC-3细胞中的某些调节蛋白结合。这些调节蛋白可能通过与雄激素受体的相互作用影响雄激素对PSA基因的诱导作用。  相似文献
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Orbital microgravity represents a unique environment, which allows the isolation of variables assumed to be involved in the mechanism of body positioning in space. In this context, the alignment of the trunk axis along allocentric references and the positioning of the body center of mass inside the supporting base compete for the role of the primary-controlled variable when assuming erect posture. This paper reports the quantitative evaluation of the postural strategies exhibited by two subjects with feet fixed to the floor of the space module along a 4-month period of exposure to microgravity. With respect to previous findings in parabolic flights and short term space missions, the analysis focused on long-term process of sensorimotor adaptation to weightlessness. Results show that while trunk-axis orientation is preserved and used as a stable postural frame of reference, the positioning of the body center of mass appears to be significantly biased backward and turns out to be involved in a long-term process of adaptation throughout the entire flight towards the re-emergence of a typically terrestrial postural regulation compatible with equilibrium. Received: 30 July 1998 / Accepted: 30 April 1999  相似文献
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