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排序方式: 共有2026条查询结果,搜索用时 15 毫秒
1.
Tomohiro Hamasaki Takahiro Matsumoto Naoya Sakamoto Akiko Shimahara Shiori Kato Ayumi Yoshitake Ayumi Utsunomiya Hisayoshi Yurimoto Esteban C. Gabazza Tadaaki Ohgi 《Nucleic acids research》2013,41(12):e126
Radioisotopes and fluorescent compounds are frequently used for RNA labeling but are unsuitable for clinical studies of RNA drugs because of the risk from radiation exposure or the nonequivalence arising from covalently attached fluorophores. Here, we report a practical phosphoramidite solid-phase synthesis of 18O-labeled RNA that avoids these disadvantages, and we demonstrate its application to quantification and imaging. The synthesis involves the introduction of a nonbridging 18O atom into the phosphate group during the oxidation step of the synthetic cycle by using 18O water as the oxygen donor. The 18O label in the RNA was stable at pH 3–8.5, while the physicochemical and biological properties of labeled and unlabeled short interfering RNA were indistinguishable by circular dichroism, melting temperature and RNA-interference activity. The 18O/16O ratio as measured by isotope ratio mass spectrometry increased linearly with the concentration of 18O-labeled RNA, and this technique was used to determine the blood concentration of 18O-labeled RNA after administration to mice. 18O-labeled RNA transfected into human A549 cells was visualized by isotope microscopy. The RNA was observed in foci in the cytoplasm around the nucleus, presumably corresponding to endosomes. These methodologies may be useful for kinetic and cellular-localization studies of RNA in basic and pharmaceutical studies. 相似文献
2.
S Ogita M Imanaka T Takebayashi Y Nakai H Fukumasu S Matsuo M Matsumoto B Tanaka K Iwanaga 《The Annals of physiological anthropology》1990,9(2):93-98
For the purpose of determining the most reasonable lying posture for pregnant women, we investigated the lying positions of both 247 non-pregnant women and 302 pregnant women during sleep. As for the rate of each position during the entire period of observation, 33.2% of the non-pregnant women were in the supine position, 41.2% in the lateral position, 18.4% in Sims' position and 7.1% in the prone position. In the pregnant group, the rate of supine position, simple lateral position and Sims' position was 34.2%, 52.2% and 12.7%, respectively, but the rate of the prone position was limited to 0.8%. All of the gravidas assuming the prone position were at less than 16 weeks of gestation. Non-pregnant women could sleep in a variety of positions, but pregnant women could assume the prone position during sleep only in the stage when the abdomen is not yet prominent or distended. Pregnant women were restricted significantly, either consciously or unconsciously, with progress in gestation. 相似文献
3.
Leading and lagging strand synthesis at the replication fork of bacteriophage T7. Distinct properties of T7 gene 4 protein as a helicase and primase 总被引:11,自引:0,他引:11
Reactions at the replication fork of bacteriophage T7 have been reconstituted in vitro on a preformed replication fork. A minimum of three proteins is required to catalyze leading and lagging strand synthesis. The T7 gene 4 protein, which exists in two forms of molecular weight 56,000 and 63,000, provides helicase and primase activities. A tight complex of the T7 gene 5 protein and Escherichia coli thioredoxin provides DNA polymerase activity. Gene 4 protein and DNA polymerase catalyze processive leading strand synthesis. Gene 4 protein molecules serving as helicase remain bound to the template as leading strand synthesis proceeds greater than 40 kilobases. Primer synthesis for lagging strand synthesis is catalyzed by additional gene 4 protein molecules that undergo multiple association/dissociation steps to catalyze multiple rounds of primer synthesis. The smaller molecular weight form of gene 4 protein has been purified from an equimolar mixture of both forms. Removal of the large form results in the loss of primase activity but not of helicase activity. Submolar amounts of the large form present in a mixture of both forms are sufficient to restore high specific activity of primase characteristic of an equimolar mixture of both forms. These results suggest that the gene 4 primase is an oligomer which is composed of both molecular weight forms. The large form may be the distributive component of the primase which dissociates from the template after each round of primer synthesis. 相似文献
4.
Summary The Catecholaminergic innervation of neurons containing growth hormone-releasing factor (GRF) was examined by use of a method which combined either 5-hydroxydopamine (5-OHDA) uptake or autoradiography after intraventricular injection of 3H-noradrenaline with immunocytochemistry for GRF in the same tissue sections at the electron-microscopic level. In the ventrolateral part of the arcuate nucleus of the rat hypothalamus a large number of immunonegative axon terminals were found to make synaptic contact with GRF-like immunoreactive (GRF-LI) cell bodies and processes. 3H-noradrenaline autoradiography or 5-OHDA-labeling combined with GRF immunocytochemistry revealed that axon terminals labeled with 3H-noradrenaline or 5-OHDA make synaptic contact with the GRF-LI nerve cell bodies and processes. These findings indicate that catecholamine-containing neurons innervate GRF neurons to regulate GRF secretion via synapses in the rat arcuate nucleus. 相似文献
5.
Masafumi Abe Naoya Nakamura Shirou Fukuhara Takamasa Hayashi Keiki Kawakami Kenkichi Kita Toshifumi Kinoshita Toyoro Ohsato Haruki Wakasa 《Virchows Archiv. B, Cell pathology including molecular pathology》1990,59(1):107-113
A new human acute lymphoblastic leukemia (ALL) cell line, designated HBL-3, was established from the bone marrow of a patient
with non-T-ALL. The HBL-3 cell line expressed B4 (CD 19), BA-1 (CD 24) and HLA-DR antigens, but not surface immunoglobulin
(SIg) or cytoplasmic immunoglobulin (CIg). The cell line lacked the common acute lymphoblastic leukemia antigen (CALLA) and
antigenic markers characteristic of T-cell and myeloid cell lineages. The HBL-3 cells had structural rearrangements of both
the homologous chromosome 9s, including a translocation with chromosome 1 which has been reported in a patient with common
ALL. The cell line had rearranged immunoglobulin heavy chain genes but retained germ-line κ light chain genes and germ-line
T-cell receptorβ- and γ-chain genes. The HBL-3 cell line was strongly positive for terminal deoxynucleotidyl transferase (TdT). These findings
indicate that the HBL-3 cell line is derived from the earliest B-cell committed to B-cell lineage. 相似文献
6.
Flavonoids inhibit the expression of heat shock proteins 总被引:14,自引:0,他引:14
N Hosokawa K Hirayoshi A Nakai Y Hosokawa N Marui M Yoshida T Sakai H Nishino A Aoike K Kawai 《Cell structure and function》1990,15(6):393-401
Cells exposed to several forms of stress, such as heat shock, transiently synthesize a group of proteins called heat shock proteins (hsps). Although many stressors other than heat shock are known to induce hsps, inhibitors of hsp expression have never been reported. Here we show that quercetin and several other flavonoids inhibit the synthesis of hsps induced by heat shock in two human cell lines, Hela cells and COLO320 DM cells. Quercetin inhibited the induction of hsp70 at the level of mRNA accumulation. This is the first report to describe the inhibition of hsp expression by reagents. 相似文献
7.
Expression of adrenocorticotropin-releasing hormone precursor gene in placenta and other nonhypothalamic tissues in man 总被引:1,自引:0,他引:1
T Usui Y Nakai T Tsukada H Jingami H Takahashi J Fukata H Imura 《Molecular endocrinology (Baltimore, Md.)》1988,2(9):871-875
Adrenocorticotropin-releasing hormone (CRH) is a peptide originally isolated from the hypothalamus. Immunocytochemical and RIA studies have revealed that CRH-like peptide is also localized in human nonhypothalamic tissues and some tumors. To see if CRH is synthesized in these nonhypothalamic tissues and tumors, we examined preproCRH mRNA in these tissues by Northern blot analysis using a cloned human preproCRH gene as a probe. PreproCRH mRNA was detected in human hypothalamus, cerebral cortex, adrenal gland, placenta, pheochromocytoma, and thymic carcinoid. The content of preproCRH mRNA in placenta was apparently greater than that in the whole hypothalamus. 相似文献
8.
M Hirai S Miyabo E Ooya K Miyanaga N Aoyagi K Kimura S Kishida T Nakai 《Life sciences》1991,48(24):2359-2363
Endothelin-3 (ET-3) is a member of the novel vasoconstrictive peptide family, identified in porcine central nervous system. Intravenous bolus injection of 1000 pmol/kg of ET-3 in freely moving rats caused significant increases in plasma ACTH and corticosterone levels, almost equivalent to those of 100 pmol/kg of rat corticotropin-releasing hormone (rCRH). The action of ET-3 was virtually abolished by pretreatment of CRH-antagonist, alpha-helical CRH. When ET-3 was added to cultured anterior pituitary cells, neither direct stimulation of ACTH release nor potentiation of rCRH action was noted. The results indicate that ET-3 may function as a neuropeptide and stimulation of the CRH-neurons, direct or inderect, is mainly responsible for activation of ACTH and corticosterone release. 相似文献
9.
Increase in serotonin 5-HT1A receptors in prefrontal and temporal cortices of brains from patients with chronic schizophrenia. 总被引:2,自引:0,他引:2
Binding studies with [3H]8-hydroxy-2-(di-n-propylamino)tetralin ([3H]8-OH-DPAT), a specific serotonin1A (5-HT1A) receptor agonist, were done on the autopsied brains from control subjects and from patients with chronic schizophrenia. All the patients and controls were of the Japanese race. In the controls, representative Scatchard plots for the specific [3H]8-OH-DPAT bindings in the prefrontal cortex and hippocampus revealed a single component of high affinity binding site (Kd value = 5.7 and 5.9 nM, Bmax value = 80.1 and 101.0 fmol/mg protein, respectively). The [3H]8-OH-DPAT bindings to the prefrontal cortex and hippocampus were potently inhibited by serotonin (IC50 = 6.3 x 10(-9) M) and 5-HT1A agonists (IC50 = 5.0 x 10(-9) - 2.3 x 10(-7) M), while other neurotransmitters, 5-HT2 and 5-HT3 related compounds did not inhibit the binding (IC50 greater than 10(-5) M). The bindings were decreased in the presence of 0.1mM GTP and 0.1mM GppNHp but not in the presence of 0.1mM GMP. In the prefrontal and temporal cortices of schizophrenics, there was a significant increase in the specific [3H]8-OH-DPAT binding, by 40% and 60%, respectively, with no change in the hippocampus, amygdala, cingulum, motor cortex, parietal or occipital cortex, as compared to findings in the controls. Scatchard analysis showed that this increased binding reflects changes in the number of sites but not in the affinity. The effect of 0.1mM GppNHp on the binding to prefrontal cortex was observed in both controls and schizophrenic patients. The bindings were significantly greater in the schizophrenic patients than in controls, in the presence of 0.1mM GppNHp. Our findings suggest that there are GTP-sensitive 5-HT1A sites in the human brain and that selective increases in GTP-sensitive 5-HT1A sites in the prefrontal and temporal cortices of schizophrenics relate to the pathophysiology of schizophrenia. 相似文献
10.
R Y Osamura Y Suemizu S Yoshimura S Hori K Inada K Watanabe Y Nakai H Imura 《Peptides》1991,12(3):503-507
In order to elucidate the relationship between secretory pathway and processing for precursor molecule of peptide hormones, we performed immunoelectron microscopic studies to localize POMC-derived peptides in mouse cultured L cells (fibroblasts without secretory granules) and in mouse AtT20 cells (ACTH secreting pituitary tumor cells with secretory granules) which had been transformed with human POMC gene. From the electron microscopic localization patterns, L42 cells were considered to serve as a model of constitutive pathway without processing of POMC, and A53 cells were considered to serve as a model of transgranular (regulated) pathway with processing of POMC. Immunoblotting supported these interpretations. 相似文献