188 research outputs found
The preprophase band-associated kinesin-14 OsKCH2 is a processive minus-end-directed microtubule motor.
In animals and fungi, cytoplasmic dynein is a processive minus-end-directedΒ motor that plays dominant roles in various intracellular processes. In contrast, land plants lack cytoplasmic dynein but contain many minus-end-directed kinesin-14s. No plant kinesin-14 is known to produce processive motility as a homodimer. OsKCH2 is a plant-specific kinesin-14 with an N-terminal actin-binding domain and a central motor domain flanked by two predicted coiled-coilsΒ (CC1 and CC2). Here, we show that OsKCH2 specifically decorates preprophase band microtubules in vivo and transports actin filaments along microtubules in vitro. Importantly, OsKCH2 exhibits processive minus-end-directed motility on single microtubules as individual homodimers. We find that CC1, but not CC2, forms the coiled-coilΒ to enable OsKCH2 dimerization. Instead, our results reveal that removing CC2 renders OsKCH2 a nonprocessive motor. Collectively, these results show that land plants have evolved unconventional kinesin-14 homodimers with inherent minus-end-directed processivity that may function to compensate for the loss of cytoplasmic dynein
Future Directions: Study Protocol for an Effectiveness-Implementation Hybrid Evaluation of a State-based Social Housing Strategy and Three Social Housing Programs
Background: In the Australian state of New South Wales nearly 60,000 approved applicants are waiting for social housing. Future Directions for Social Housing is a response to this challenge. This collection of housing programs aims to provide more social housing, support and incentives for leaving social housing and a better social housing experience. This document presents the protocol of the evaluation of these programs and the overarching Future Directions Strategy.
Methods/Design: The evaluation will use a Type 1 effectiveness-implementation hybrid design, with an integrated, dual focus on assessing the effectiveness of Future Directions and better understanding the context for reform implementation. Program effectiveness will be examined using quasi-experimental techniques applied to linked administrative data. The implementation context will be examined via program level data, qualitative interviews and focus groups with stakeholders and tenants. Some quantitative survey and administrative data will also be used. Findings from the implementation evaluation will be used to inform and interpret the effectiveness evaluation. Economic evaluations will also be conducted.
Discussion: This methodology will produce a high-quality evaluation of a large, complex government program which aims to facilitate rapid translational gains, real-time adoption of effective implementation strategies and generate actionable insights for policymakers
Entering and Exiting the Medicare Part D Coverage Gap: Role of Comorbidities and Demographics
Background: Some Medicare Part D enrollees whose drug expenditures exceed a threshold enter a coverage gap with full cost-sharing, increasing their risk for reduced adherence and adverse outcomes. Objective: To examine comorbidities and demographic characteristics associated with gap entry and exit. Design: We linked 2005-2006 pharmacy, outpatient, and inpatient claims to enrollment and Census data. We used logistic regression to estimate associations of 2006 gap entry and exit with 2005 medical comorbidities, demographics, and Census block characteristics. We expressed all results as predicted percentages. PATIENTS: 287,713 patients without gap coverage, continuously enrolled in a Medicare Advantage Part D (MAPD) plan serving eight states. Patients who received a low-income subsidy, could not be geocoded, or had no 2006 drug fills were excluded. Results: Of enrollees, 15.9% entered the gap, 2.6% within the first 180 days; among gap enterers, only 6.7% exited again. Gap entry was significantly associated with female gender and all comorbidities, particularly dementia (39.5% gap entry rate) and diabetes (28.0%). Among dementia patients entering the gap, anti-dementia drugs (donepezil, memantine, rivastigmine, and galantamine) and atypical antipsychoticmedications (risperidone, quetiapine, and olanzapine) together accounted for 40% of pre-gap expenditures. Among diabetic patients, rosiglitazone accounted for 7.2% of pre-gap expenditures. Having dementia was associated with twice the risk of gap exit. Conclusions: Certain chronically ill MAPD enrollees are at high risk of gap entry and exposure to unsubsidized medication costs. Clinically vulnerable populations should be counseled on how to best manage costs through drug substitution or discontinuation of specific, non-essential medications. Β© 2010 Society of General Internal Medicine
Patient-provider communication regarding drug costsin Medicare Part D beneficiaries with diabetes: a TRIAD Study
<p>Abstract</p> <p>Background</p> <p>Little is known about drug cost communications of Medicare Part D beneficiaries with chronic conditions such as diabetes. The purpose of this study is to assess Medicare Part D beneficiaries with diabetes' levels of communication with physicians regarding prescription drug costs; the perceived importance of these communications; levels of prescription drug switching due to cost; and self-reported cost-related medication non-adherence.</p> <p>Methods</p> <p>Data were obtained from a cross-sectional survey (58% response rate) of 1,458 Medicare beneficiaries with diabetes who entered the coverage gap in 2006; adjusted percentages of patients with communication issues were obtained from multivariate regression analyses adjusting for patient demographics and clinical characteristics.</p> <p>Results</p> <p>Fewer than half of patients reported discussing the cost of medications with their physicians, while over 75% reported that such communications were important. Forty-eight percent reported their physician had switched to a less expensive medication due to costs. Minorities, females, and older adults had significantly lower levels of communication with their physicians regarding drug costs than white, male, and younger patients respectively. Patients with < $25 K annual household income were more likely than higher income patients to have talked about prescription drug costs with doctors, and to report cost-related non-adherence (27% vs. 17%, p < .001).</p> <p>Conclusions</p> <p>Medicare Part D beneficiaries with diabetes who entered the coverage gap have low levels of communication with physicians about drug costs, despite the high perceived importance of such communication. Understanding patient and plan-level characteristics differences in communication and use of cost-cutting strategies can inform interventions to help patients manage prescription drug costs.</p
Two-Dimensional Molecular Electronics Circuits
Addressing an array of bistable [2]rotaxanes through a twoβdimensional crossbar arrangement provides the device element of a currentβdriven molecular electronic circuit. The development of the [2]rotaxane switches through an iterative, evolutionary process is described. The arrangement reported here allows both memory and logic functions to use the same elements
Gene Transfer of Pro-opiomelanocortin Prohormone Suppressed the Growth and Metastasis of Melanoma: Involvement of β£-Melanocyte-Stimulating Hormone-Mediated Inhibition of the Nuclear Factor B/Cyclooxygenase-2 Pathway
ABSTRACT Pro-opiomelanocortin (POMC) is a prohormone of various neuropeptides, including corticotropin, β£-melanocyte-stimulating hormone (β£-MSH), and β€-endorphin (β€-EP) . POMC neuropeptides are potent inflammation inhibitors and immunosuppressants and may exert opposite influences during tumorigenesis. However, the role of POMC expression in carcinogenesis remains elusive. We evaluated the antineoplastic potential of POMC gene delivery in a syngenic B16-F10 melanoma model. Adenovirus-mediated POMC gene delivery in B16-F10 cells increased the release of POMC neuropeptides in cultured media, which differentially regulated the secretion of pro-and anti-inflammatory cytokines in lymphocytes. POMC gene transfer significantly reduced the anchorage-independent growth of melanoma cells. Moreover, pre-or post-treatment with POMC gene delivery effectively retarded the melanoma growth in mice. Intravenous injection of POMC-transduced B16-F10 cells resulted in reduced foci formation in lung by 60 to 70% of control. The reduced metastasis of POMC-transduced B16-F10 cells could be attributed to their attenuated migratory and adhesive capabilities. POMC gene delivery reduced the cyclooxygenase-2 (COX-2) expression and prostaglandin (PG) E 2 synthesis in melanoma cells and tumor tissues. In addition, application of NS-398, a selective COX-2 inhibitor, mimicked the antineoplastic functions of POMC gene transfer in melanoma. The POMC-mediated COX-2 down-regulation was correlated with its inhibition of nuclear factor B (NFB) activities. Exogenous supply of β£-MSH inhibited NFB activities, whereas application of the β£-MSH antagonist growth hormone-releasing peptide-6 (GHRP-6) abolished the POMC-induced inhibition of NFB activities and melanoma growth in mice. In summary, POMC gene delivery suppresses melanoma via β£-MSH-induced inhibition of NFB/COX-2 pathway, thereby constituting a novel therapy for melanoma. POMC is a multifunctional polycistronic gene located on human chromosome 2p23.3. POMC is a 31 kDa prohormone that is processed into various neuropeptides, including corticotropin, melanotropins (β£-, β€-, and β₯-MSH), lipotropins, and β€-endorphin (β€-EP
H5N1 and 1918 Pandemic Influenza Virus Infection Results in Early and Excessive Infiltration of Macrophages and Neutrophils in the Lungs of Mice
Fatal human respiratory disease associated with the 1918 pandemic influenza virus and potentially pandemic H5N1 viruses is characterized by severe lung pathology, including pulmonary edema and extensive inflammatory infiltrate. Here, we quantified the cellular immune response to infection in the mouse lung by flow cytometry and demonstrate that mice infected with highly pathogenic (HP) H1N1 and H5N1 influenza viruses exhibit significantly high numbers of macrophages and neutrophils in the lungs compared to mice infected with low pathogenic (LP) viruses. Mice infected with the 1918 pandemic virus and a recent H5N1 human isolate show considerable similarities in overall lung cellularity, lung immune cell sub-population composition and cellular immune temporal dynamics. Interestingly, while these similarities were observed, the HP H5N1 virus consistently elicited significantly higher levels of pro-inflammatory cytokines in whole lungs and primary human macrophages, revealing a potentially critical difference in the pathogenesis of H5N1 infections. These results together show that infection with HP influenza viruses such as H5N1 and the 1918 pandemic virus leads to a rapid cell recruitment of macrophages and neutrophils into the lungs, suggesting that these cells play a role in acute lung inflammation associated with HP influenza virus infection. In addition, primary macrophages and dendritic cells were also susceptible to 1918 and H5N1 influenza virus infection in vitro and in infected mouse lung tissue
Linking Hydrothermal Geochemistry to Organismal Physiology: Physiological Versatility in Riftia pachyptila from Sedimented and Basalt-hosted Vents
Much of what is known regarding Riftia pachyptila physiology is based on the wealth of studies of tubeworms living at diffuse flows along the fast-spreading, basalt-hosted East Pacific Rise (EPR). These studies have collectively suggested that Riftia pachyptila and its chemoautotrophic symbionts are physiologically specialized, highly productive associations relying on hydrogen sulfide and oxygen to generate energy for carbon fixation, and the symbiont's nitrate reduction to ammonia for energy and biosynthesis. However, Riftia also flourish in sediment-hosted vents, which are markedly different in geochemistry than basalt-hosted systems. Here we present data from shipboard physiological studies and global quantitative proteomic analyses of Riftia pachyptila trophosome tissue recovered from tubeworms residing in the EPR and the Guaymas basin, a sedimented, hydrothermal vent field. We observed marked differences in symbiont nitrogen metabolism in both the respirometric and proteomic data. The proteomic data further suggest that Riftia associations in Guaymas may utilize different sulfur compounds for energy generation, may have an increased capacity for energy storage, and may play a role in degrading exogenous organic carbon. Together these data reveal that Riftia symbionts are far more physiologically plastic than previously considered, and that -contrary to previous assertions- Riftia do assimilate reduced nitrogen in some habitats. These observations raise new hypotheses regarding adaptations to the geochemical diversity of habitats occupied by Riftia, and the degree to which the environment influences symbiont physiology and evolution
Necdin, a p53-Target Gene, Is an Inhibitor of p53-Mediated Growth Arrest
In vitro, cellular immortalization and transformation define a model for multistep carcinogenesis and current ongoing challenges include the identification of specific molecular events associated with steps along this oncogenic pathway. Here, using NIH3T3 cells, we identified transcriptionally related events associated with the expression of Polyomavirus Large-T antigen (PyLT), a potent viral oncogene. We propose that a subset of these alterations in gene expression may be related to the early events that contribute to carcinogenesis. The proposed tumor suppressor Necdin, known to be regulated by p53, was within a group of genes that was consistently upregulated in the presence of PyLT. While Necdin is induced following p53 activation with different genotoxic stresses, Necdin induction by PyLT did not involve p53 activation or the Rb-binding site of PyLT. Necdin depletion by shRNA conferred a proliferative advantage to NIH3T3 and PyLT-expressing NIH3T3 (NIHLT) cells. In contrast, our results demonstrate that although overexpression of Necdin induced a growth arrest in NIH3T3 and NIHLT cells, a growing population rapidly emerged from these arrested cells. This population no longer showed significant proliferation defects despite high Necdin expression. Moreover, we established that Necdin is a negative regulator of p53-mediated growth arrest induced by nutlin-3, suggesting that Necdin upregulation could contribute to the bypass of a p53-response in p53 wild type tumors. To support this, we characterized Necdin expression in low malignant potential ovarian cancer (LMP) where p53 mutations rarely occur. Elevated levels of Necdin expression were observed in LMP when compared to aggressive serous ovarian cancers. We propose that in some contexts, the constitutive expression of Necdin could contribute to cancer promotion by delaying appropriate p53 responses and potentially promote genomic instability
Integrated Molecular Characterization of Uterine Carcinosarcoma
SummaryWe performed genomic, epigenomic, transcriptomic, and proteomic characterizations of uterine carcinosarcomas (UCSs). Cohort samples had extensive copy-number alterations and highly recurrent somatic mutations. Frequent mutations were found in TP53, PTEN, PIK3CA, PPP2R1A, FBXW7, and KRAS, similar to endometrioid and serous uterine carcinomas. Transcriptome sequencing identified a strong epithelial-to-mesenchymal transition (EMT) gene signature in a subset of cases that was attributable to epigenetic alterations at microRNA promoters. The range of EMT scores in UCS was the largest among all tumor types studied via The Cancer Genome Atlas. UCSs shared proteomic features with gynecologic carcinomas and sarcomas with intermediate EMT features. Multiple somatic mutations and copy-number alterations in genes that are therapeutic targets were identified
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