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71.
72.
High frequency of defective nef alleles in a long-term survivor with nonprogressive human immunodeficiency virus type 1 infection. 总被引:4,自引:1,他引:3
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R Mariani F Kirchhoff T C Greenough J L Sullivan R C Desrosiers J Skowronski 《Journal of virology》1996,70(11):7752-7764
A large number of nef alleles were obtained from peripheral blood mononuclear cells (PBMC) of four long-term nonprogressing survivors of human immunodeficiency virus type 1 (HIV-1) infection and from five individuals with progressive HIV-1 infection. These primary nef alleles were characterized by DNA sequence analysis and for their ability to downregulate CD4 surface expression. Intact nef open reading frames that directed the expression of Nef protein were recovered from all of the individuals. Most of the Nef proteins derived from three of four individuals with nonprogressive infection and from all five individuals with progressive infection were functional as judged by their ability to induce a decrease in surface CD4 expression. In contrast, one individual with nonprogressive HIV-1 infection yielded an unusually high frequency of disrupted nef open reading frames and Nef proteins defective for CD4 downregulation. Approximately 70% of the nef clones obtained from the PBMC of this individual at eight time points over a 12-year period were disrupted or defective for CD4 downregulation. While functional Nef proteins were demonstrated early in the course of infection (1983), functional nef alleles have surprisingly not come to predominate over time in PBMC DNA in this individual. 相似文献
73.
Hong Zhao Jinmin Zhu Kemi Cui Xiaoyin Xu Megan O'Brien Kelvin K Wong Santosh Kesari Weiming Xia Stephen TC Wong 《Cancer cell international》2009,9(1):15
Background
Cancer and Alzheimer's disease (AD) are two seemingly distinct diseases and rarely occur simultaneously in patients. To explore molecular determinants differentiating pathogenic routes towards AD or cancer, we investigate the role of amyloid β protein (Aβ) on multiple tumor cell lines that are stably expressing luciferase (human glioblastoma U87; human breast adenocarcinoma MDA-MB231; and mouse melanoma B16F). 相似文献74.
†‡ Ivan Jeanne Weiler †‡William S. Childers †‡§William T. Greenough 《Journal of neurochemistry》1996,66(1):197-202
Abstract: Stimulation of synaptoneurosome suspensions by the neurotransmitter glutamate gives rise to rapid loading of ribosomes onto mRNA and increased incorporation of amino acids into trichloroacetic acid-precipitable polypeptides. Metabotropic glutamate receptors (mGluRs) are responsible for this effect. Although simultaneous Ca2+ entry and mGluR stimulation do not change the response, entry of Ca2+ 30 s or 3 min before mGluR stimulation markedly depresses the polyribosomal loading. Either NMDA or ionophore (A23187) produces the depression. A calmodulin antagonist, W7, alleviates the effect, suggesting that inactivation of phospholipase A2 by calcium-calmodulin-dependent kinase II is partially responsible for the phenomenon. Thus, interaction between different classes of glutamate receptors affects the control of protein translation at the synapse. This effect may partially explain recent observations of negative interactions between receptor classes in induction of long-term potentiation. 相似文献
75.
76.
Results of a questionnaire on use of glass syringes among diabetic patients showed considerable variation in methods of keeping the syringes and in the duration of their useful life. Thirty patients took part in an investigation in which each patient used the same disposable syringe in place of the glass syringe for up to two months. No clinical or bacteriological evidence of infection was found. Used in this way, disposable syringes were less expensive than glass syringes. They are lighter than glass syringes, less susceptible to damage, and more easily carried on journeys. 相似文献
77.
Tobamoviruses, mostly isolated from solanaceous plants, may represent
ancient virus lineages that have codiverged with their hosts. Recently
completed nucleotide sequences of six nonsolanaceous tobamoviruses allowed
assessment of the codivergence hypothesis and support a third subgroup
within tobamoviruses. The genomic sequences of 12 tobamoviruses and the
partial sequences of 11 others have been analyzed. Comparisons of the
predicted protein sequences revealed three clusters of tobamoviruses,
corresponding to those infecting solanaceous species (subgroup 1), those
infecting cucurbits and legumes (subgroup 2), and those infecting
crucifers. The orchid-infecting odontoglossum ringspot tobamovirus was
associated with subgroup 1 genomes by its coat and movement protein
sequences, but with the crucifer-pathogenic tobamoviruses by the remainder
of its genome, suggesting that it is the progeny of a recombinant. For four
of five genomic regions, subgroup 1 and 3 genomes were equidistant from a
subgroup 2 genome chosen for comparison, suggesting uniform rates of
evolution. A phylogenetic tree of plant families based on the tobamoviruses
they harbor was congruent with that based on rubisco sequences but had a
different root, suggesting that codivergence was tempered by rare events of
viruses of one family colonizing another family. The proposed subgroup 3
viruses probably have an origin of virion assembly in the movement protein
gene, a large (25-codon) overlap of movement and coat protein open reading
frames, and a comparably shorter genome. Codon-position- dependent base
compositions and codon prevalences suggested that the coat protein frame of
the overlap region was ancestral. Bootstrapped parsimony analysis of the
nucleotides in the overlap region and of the sequences translated from the
-1 frame (the subgroup 3 movement protein frame) of this region produced
trees inconsistent with those deduced from other regions. The results are
consistent with a model in which a no or short overlap organization was
ancestral. Despite encoding of subgroup 2 and 3 movement protein C-termini
by nonhomologous nucleotides, weak similarities between their amino acid
sequences suggested convergent sequence evolution.
相似文献
78.
Gang Li Tianming Liu Ashley Tarokh Jingxin Nie Lei Guo Andrew Mara Scott Holley Stephen TC Wong 《BMC cell biology》2007,8(1):40
Background
Reliable segmentation of cell nuclei from three dimensional (3D) microscopic images is an important task in many biological studies. We present a novel, fully automated method for the segmentation of cell nuclei from 3D microscopic images. It was designed specifically to segment nuclei in images where the nuclei are closely juxtaposed or touching each other. The segmentation approach has three stages: 1) a gradient diffusion procedure, 2) gradient flow tracking and grouping, and 3) local adaptive thresholding. 相似文献79.
Background
Automated identification of cell cycle phases of individual live cells in a large population captured via automated fluorescence microscopy technique is important for cancer drug discovery and cell cycle studies. Time-lapse fluorescence microscopy images provide an important method to study the cell cycle process under different conditions of perturbation. Existing methods are limited in dealing with such time-lapse data sets while manual analysis is not feasible. This paper presents statistical data analysis and statistical pattern recognition to perform this task. 相似文献80.
Janet E. Squires Danielle Cho-Young Laura D. Aloisio Robert Bell Stephen Bornstein Susan E. Brien Simon Decary Melissa Demery Varin Mark Dobrow Carole A. Estabrooks Ian D. Graham Megan Greenough Doris Grinspun Michael Hillmer Tanya Horsley Jiale Hu Alan Katz Christina Krause John Lavis Wendy Levinson Adrian Levy Michelina Mancuso Steve Morgan Letitia Nadalin-Penno Andrew Neuner Tamara Rader Wilmer J. Santos Gary Teare Joshua Tepper Amanda Vandyk Michael Wilson Jeremy M. Grimshaw 《CMAJ》2022,194(8):E279
Background:Inappropriate health care leads to negative patient experiences, poor health outcomes and inefficient use of resources. We aimed to conduct a systematic review of inappropriately used clinical practices in Canada.Methods:We searched multiple bibliometric databases and grey literature to identify inappropriately used clinical practices in Canada between 2007 and 2021. Two team members independently screened citations, extracted data and assessed methodological quality. Findings were synthesized in 2 categories: diagnostics and therapeutics. We reported ranges of proportions of inappropriate use for all practices. Medians and interquartile ranges (IQRs), based on the percentage of patients not receiving recommended practices (underuse) or receiving practices not recommended (overuse), were calculated. All statistics are at the study summary level.Results:We included 174 studies, representing 228 clinical practices and 28 900 762 patients. The median proportion of inappropriate care, as assessed in the studies, was 30.0% (IQR 12.0%–56.6%). Underuse (median 43.9%, IQR 23.8%–66.3%) was more frequent than overuse (median 13.6%, IQR 3.2%–30.7%). The most frequently investigated diagnostics were glycated hemoglobin (underused, range 18.0%–85.7%, n = 9) and thyroid-stimulating hormone (overused, range 3.0%–35.1%, n = 5). The most frequently investigated therapeutics were statin medications (underused, range 18.5%–71.0%, n = 6) and potentially inappropriate medications (overused, range 13.5%–97.3%, n = 9).Interpretation:We have provided a summary of inappropriately used clinical practices in Canadian health care systems. Our findings can be used to support health care professionals and quality agencies to improve patient care and safety in Canada.As health care systems struggle with sustainability, there is increased recognition that a substantial percentage of the health care received is inappropriate.1 Inappropriate health care occurs when effective clinical practices are underused, ineffective clinical practices are overused or other practices are misused. It can lead to negative patient experiences,2 poor health outcomes3,4 and inefficient use of scarce health care resources.5 In response, there is widespread professional and policy interest in reducing inappropriate health care in Canada and abroad. For example, in 2014, Choosing Wisely Canada,6 a physician-led campaign in partnership with the Canadian Medical Association, was established. This initiative encourages conversations between clinicians and patients about low-value or overused care in efforts to reduce inappropriate care. Choosing Wisely Canada is endorsed across Canada by all provincial and territorial medical associations (https://choosingwiselycanada.org/about/).Although reducing inappropriate health care is a high priority for health care professionals, agencies and governments in Canada, designing effective initiatives for quality improvement has been a difficult goal to achieve without knowledge of which clinical practices are inappropriately used. This is further challenged because Canada does not have a mandatory and comprehensive national tracking system for quality. The Canadian Institute for Health Information (CIHI) houses multiple Canadian health databases, but it does not collect information on all clinical practices. Therefore, a systematic synthesis is necessary to provide an overview of inappropriate health care in Canada.7 Summaries of inappropriately used clinical practices exist for several countries: United States,8,9 United Kingdom10 and Australia.11 Each of these syntheses found high levels (50% on average) of inappropriately used practices and laid the foundation for several quality improvement initiatives in these countries. We aimed to conduct a systematic review to estimate the nature and amount of inappropriately used clinical practices in Canada. 相似文献