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排序方式: 共有416条查询结果,搜索用时 312 毫秒
121.
Journal of Ichthyology - The diet composition, stomach fullness, and condition factor of different size groups of the Atka mackerel Pleurogrammus monopterygius were studied in the area of the... 相似文献
122.
Beta-amyloid pathology, the main hallmark of Alzheimer's disease (AD), has been linked to its conformational status and aggregation. We recently showed that site-directed monoclonal antibodies (mAbs) towards the N-terminal region of the human beta-amyloid peptide bind to preformed beta-amyloid fibrils (Abeta), leading to disaggregation and inhibition of their neurotoxic effect. Here we report the development of a novel immunization procedure to raise effective anti-aggregating amyloid beta-protein (AbetaP) antibodies, using as antigen filamentous phages displaying the only EFRH peptide found to be the epitope of these antibodies. Due to the high antigenicity of the phage no adjuvant is required to obtain high affinity anti-aggregating IgG antibodies in animals model, that exhibit identity to human AbetaP. Such antibodies are able to sequester peripheral AbetaP, thus avoiding passage through the blood brain barrier (BBB) and, as recently shown in a transgenic mouse model, to cross the BBB and dissolve already formed beta-amyloid plaques. To our knowledge, this is the first attempt to use as a vaccine a self-anti-aggregating epitope displayed on a phage, and this may pave the way to treat abnormal accumulation-peptide diseases, such as Alzheimer's disease or other amyloidogenic diseases. 相似文献
123.
124.
Use of amplicon-6 vectors derived from human herpesvirus 6 for efficient expression of membrane-associated and -secreted proteins in T cells
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The composite amplicon-6 vectors, which are derived from human herpesvirus 6 (HHV-6), can target hematopoietic cells. In the presence of the respective helper viruses, the amplicons are replicated by the rolling circle mechanism, yielding defective genomes of overall size 135 to 150 kb, composed of multiple repeats of units, containing the viral DNA replication origin, packaging signals, and the selected transgene(s). We report the use of amplicon-6 vectors designed for transgene expression in T cells. The selected transgenes included the green fluorescent protein marker, the herpes simplex virus type 1 glycoprotein D (gD), and the gD gene deleted in the transmembrane region (gDsec). The vectors were tested after electroporation and passage in T cells with or without helper HHV-6A superinfections. The results were as follows. (i)The vectors could be passaged both as cell-associated and as cell-free secreted virions infectious to new cells. (ii)The intact gD accumulated at the cell surface, whereas the gDsec was dispersed at internal locations of the cells or was secreted into the medium. (iii)Analyses of amplicon-6-gD expression by flow cytometry have shown significant expression in cultures with reiterated amplicons and helper viruses. The vector has spread to >60% of the cells, and the efficiency of expression per cell increased 15-fold, most likely due to the presence of concatemeric amplicon repeats. Current studies are designed to test whether amplicon-6 vectors can be used for gene therapy in lymphocytes and whether amplicon-6 vectors expressed in T cells and dendritic cells can induce strong cellular and humoral immune responses. 相似文献
125.
Frenkel SR Saadeh PB Mehrara BJ Chin GS Steinbrech DS Brent B Gittes GK Longaker MT 《Plastic and reconstructive surgery》2000,105(3):980-990
Normal and abnormal extracellular matrix turnover is thought to result, in part, from the balance in the expression of metalloproteinases and tissue inhibitors of metalloproteinases (TIMPs). The clinical manifestations of an imbalance in these relationships are evident in a variety of pathologic states, including osteoarthritis, deficient long-bone growth, rheumatoid arthritis, tumor invasion, and inadequate cartilage repair. Articular cartilage defects commonly heal as fibrocartilage, which is structurally inferior to the normal hyaline architecture of articular cartilage. Transforming growth factor-beta 1 (TGF-beta1), a cytokine central to growth, repair, and inflammation, has been shown to upregulate TIMP-1 expression in human and bovine articular cartilage. Additionally, members of the TGF-beta superfamily are thought to play key roles in chondrocyte growth and differentiation. Bone morphogenetic protein-2 (BMP-2), a member of this superfamily, has been shown to regulate chondrocyte differentiation states and extracellular matrix composition. It was proposed that, by optimizing extracellular matrix composition, BMP-2 would enhance articular cartilage healing. After determining the release kinetics of BMP-2 from a collagen type I implant (Long-Evans male rats; two implants/rat, n = 14), it was found that, in a tissue engineering application, BMP-2 induced a hyaline-like repair of New Zealand White rabbit knee articular cartilage defects (3-mm full-thickness defects in the femoral trochlea; 2 defects/rabbit, n = 36). The quality of cartilage repair with BMP-2 (with or without chondrocytes) was significantly better than defects treated with BMP-2, as assessed by a quantitative scoring scale. Immunohistochemical staining revealed TIMP-1 production in the cartilage defects treated with BMP-2. When studied in vitro, it was found that BMP-2 markedly increased TIMP-1 mRNA by both bovine articular and human rib chondrocytes. Additionally, increased TIMP-1 mRNA was translated into increased TIMP-1 protein production by bovine chondrocytes. Taken together, these data suggest that BMP-2 may be a useful cytokine to improve healing of cartilaginous defects. Furthermore, these data suggest that the beneficial effects of BMP-2 may be, in part, related to alterations in extracellular matrix turnover. 相似文献
126.
IkappaB kinase alpha regulates subcellular distribution and turnover of cyclin D1 by phosphorylation
Kwak YT Li R Becerra CR Tripathy D Frenkel EP Verma UN 《The Journal of biological chemistry》2005,280(40):33945-33952
IkappaB kinases (IKKs), IKKalpha and IKKbeta, with a regulatory subunit IKKgamma/NEMO constitute a high molecular weight IKK complex that regulates NF-kappaB activity. Although IKKalpha and IKKbeta share structural and biochemical similarities, IKKalpha has been shown to have distinct biological roles. Here we show that IKKalpha plays a critical role in regulating cyclin D1 during the cell cycle. Analysis of IKKalpha-/- mouse embryo fibroblast cells showed that cyclin D1 is overexpressed and localized in the nucleus compared with parental mouse embryo fibroblasts. IKKalpha associates with and phosphorylates cyclin D1. Analysis on cyclin D1 mutants demonstrated that IKKalpha phosphorylates cyclin D1 at Thr286. Reconstitution of IKKalpha in knockout cells leads to nuclear export and increased degradation of cyclin D1. Further, RNAi-mediated knockdown of IKKalpha results in similar changes as observed in IKKalpha-/- cells. These results suggest a novel role of IKKalpha in regulating subcellular localization and proteolysis of cyclin D1 by phosphorylation of cyclin D1 at Thr286, the same residue earlier found to be a target for glycogen synthase kinase-3beta-induced phosphorylation. 相似文献
127.
Objective: To investigate oral care provision reported by senior nurses in stroke care settings in Scotland. Background: Stroke can have adverse effects on oral care and health. Little is known about current oral care practices in stroke care settings. Materials and methods: We designed a postal survey to be completed by ward managers or senior nurses. After piloting, the survey was distributed to all 71 units in Scotland, identified as providing specialist care for patients in the acute or rehabilitation stages following stroke. Pre‐notification and reminder letters were circulated. Responses were anonymous. Results: All but one survey was completed and returned. Help from dental professionals was available to most units (64/70) mostly on request. Only a third of units received oral care training in the last year (23/70). The majority of this training was ward based (20/23). The use of oral care assessment tools and protocols was limited (16/70 and 15/70 units respectively). Not all units had access to toothbrushes, toothpaste or chlorhexidine. For patients unable to perform oral care independently, senior nurses expected the patients’ teeth or dentures to be cleaned at least twice a day in 59 of 70 and 49 of 70 units respectively. Conclusion: The response rate was excellent and has provided a national overview of oral care provision for patients in stroke care settings. Access to staff training, assessments, protocols and oral hygiene material varied considerably. This information provides a valuable baseline from which to develop and evaluate the effectiveness of ward‐based oral care interventions for stroke patients. 相似文献
128.
Evidence that low-level viremias during effective highly active antiretroviral therapy result from two processes: expression of archival virus and replication of virus
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Tobin NH Learn GH Holte SE Wang Y Melvin AJ McKernan JL Pawluk DM Mohan KM Lewis PF Mullins JI Frenkel LM 《Journal of virology》2005,79(15):9625-9634
Episodes of low-level viremia (LLV), with plasma human immunodeficiency virus type 1 (HIV-1) RNA levels ranging from 50 to 400 copies (c)/ml, occur commonly during highly active antiretroviral therapy (HAART). LLV has been associated with virologic failure of HAART in some studies, while in others LLV did not appear to affect the clinical outcome. To understand the processes leading to LLV, genetic analyses were used to determine whether plasma virions emanated from archived or from newly evolved viral genomes. Episodes of LLV (plasma HIV-1 RNA, 50 to 379 [median, 77] c/ml) were detected in 21/37 (57%) HIV-1-infected children with median plasma HIV-1 RNA levels of <50 c/ml during 79 patient years of HAART. Viral sequences were derived by direct sequencing of PCR products from 21 plasma specimens diluted to end point. In phylogenetic analysis, LLV viral sequences grouped with virus from early in the course of infection in 8/11 subjects. Six specimens had multiple identical viral sequences, suggesting origin from clonally expanded infected cells. LLV plasma virus evolved over time, indicating viral replication, in 3/11 subjects. Two of these had frequent LLV, including the selection of drug-resistant mutants. In summary, plasma virus from episodes of LLV during effective HAART appeared to originate from two distinct processes, (i) clonal outgrowth from long-lived HIV-1-infected cells, presumably following activation and proliferation of these cells, and (ii) ongoing viral replication that included the selection of new drug-resistant mutants. These observations provide a plausible explanation for the divergent clinical outcomes previously associated with LLV. 相似文献
129.
Quantitative determination of the 5-(hydroxymethyl)uracil moiety in the DNA of gamma-irradiated cells 总被引:10,自引:0,他引:10
5-(Hydroxymethyl)uracil (HMUra) is a chemically stable derivative of thymine formed through the action of ionizing radiation which we previously identified in the DNA of gamma-irradiated HeLa cells [Teebor, G. W., Frenkel, K., & Goldstein, M. S. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 318-321]. In this report, we determine whether HMUra can be used as a marker of exposure of DNA to ionizing radiation. Dose-response curves for its formation in [3H]thymidine-labeled DNA were constructed by exposing the DNA to increasing amounts of gamma-radiation and measuring the HMUra content. DNA was irradiated both in solution and in intact cells. HMUra was identified as the 2'-deoxyribonucleoside 5-(hydroxymethyl)-2'-deoxyuridine (HMdU) by subjecting the irradiated DNA to enzymatic digestion and analyzing the mixture of 2'-deoxyribonucleosides by high-pressure liquid chromatography. The identity of the radiogenically formed HMdU was confirmed by acetylation and the structure of the acetyl derivative obtained by mass and nuclear magnetic resonance spectroscopies. At two different DNA concentrations in solution, the same number of thymidine moieties were converted to HMdU, indicating that within this range of concentration the formation of HMdU was mediated through the indirect action of ionizing radiation. Equal amounts of HMdU were formed in single- and double-stranded DNA at each radiation dose, indicating that DNA conformation did not affect HMdU formation. Surprisingly, the G value (number of HMdU molecules formed/100 eV) was higher in irradiated cellular DNA than in DNA irradiated in solution.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
130.