167 research outputs found

    Clarifying water clarity: A call to use metrics best suited to corresponding research and management goals in aquatic ecosystems

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    Water clarity is a subjective term and can be measured multiple ways. Different metrics such as light attenuation and Secchi depth vary in effectiveness depending on the research or management application. In this essay, we argue that different questions merit different water clarity metrics. In coastal and inland waters, empirical relationships to estimate light attenuation can yield clarity estimates that either under- or overestimate the underwater light climate for restoration goals, such as potential habitat available for submerged aquatic vegetation. Best practices in reporting water clarity measurements include regionally specific, temporally representative calibrations and communicating the metric that was actually measured. An intentional choice of the water clarity metric best suited to the research or management question yields the most useful results

    An exploratory survey on the awareness and usage of clinical practice guidelines among clinical pharmacists

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    Background: The NHLBI has not developed clinical practice guidelines since 2007. As a result, multiple organizations have released competing guidelines. This has created confusion and debate among clinicians as to which recommendations are most applicable for practice. Objectives: To explore preliminary attitudes, awareness, and usage of clinical practice guidelines in practice and teaching for hypertension, dyslipidemia and asthma among clinical pharmacists. Methods: Clinical pharmacists across the US were surveyed electronically over a two week period in Spring 2019 regarding utilization and knowledge of practice guidelines for hypertension, dyslipidemia, and asthma. Clinical cases were included to evaluate application of guidelines. Descriptive statistics, Chi-square analysis, and Wilcoxon signed-rank test were conducted. Statistical significance level was set to 0.01 to account for multiple tests conducted on the same survey participants. Results: Forty-eight, 34, and 28 pharmacists voluntarily completed hypertension, dyslipidemia, and asthma survey questions, respectively. Interactions by disease state (p \u3c 0.001) revealed more pharmacists (93%) reporting to have ≤50% patient load in managing asthma and more pharmacists (95%) had read the full summary/report of the most recent hypertension guideline. Primary reasons why the most recent guideline was not selected were also significantly different by disease state (interaction; p \u3c 0.001). For dyslipidemia and asthma, pharmacists had a higher mean rating of agreement (p \u3c0.007) in having the most confidence in the most recent as compared to older guidelines. Proportionally more clinical cases were answered correctly (interaction; p \u3c0.001) when pharmacists applied the most recent guideline for hypertension (84%), while the opposite outcome was found for asthma (27%). Conclusion: While more pharmacists selected the most recent guideline for practice and teaching, there was inconsistent application of guidelines to clinical cases. Further studies with a larger representation of pharmacists are warranted to more definitively determine factors influencing guideline preference and usage

    Masivukeni: Development of a Multimedia Based Antiretroviral Therapy Adherence Intervention for Counselors and Patients in South Africa

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    Effective medical treatment for HIV/AIDS requires patients’ optimal adherence to antiretroviral therapy (ART). In resource-constrained settings, lack of adequate standardized counseling for patients on ART remains a significant barrier to adherence. Masivukeni (“Let’s Wake Up” in Xhosa) is an innovative multimedia-based intervention designed to help people living with HIV in resource-limited settings achieve and maintain high levels of ART adherence. Adapted from a couples-based intervention tested in the United States (US), Masivukeni was developed through community-based participatory research with US and South African partners and informed by Ewart’s Social Action Theory. Innovative computer-based multimedia strategies were used to translate a labor- and training-intensive intervention into one that could be readily and widely used by lay counselors with relatively little training with low-literacy patients. In this paper, we describe the foundations of this new intervention, the process of its development, and the evidence of its high acceptability and feasibility

    Loss of Mitochondrial Ndufs4 in Striatal Medium Spiny Neurons Mediates Progressive Motor Impairment in a Mouse Model of Leigh Syndrome

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    Inability of mitochondria to generate energy leads to severe and often fatal myoencephalopathies. Among these, Leigh syndrome (LS) is one of the most common childhood mitochondrial diseases; it is characterized by hypotonia, failure to thrive, respiratory insufficiency and progressive mental and motor dysfunction, leading to early death. Basal ganglia nuclei, including the striatum, are affected in LS patients. However, neither the identity of the affected cell types in the striatum nor their contribution to the disease has been established. Here, we used a mouse model of LS lacking Ndufs4, a mitochondrial complex I subunit, to confirm that loss of complex I, but not complex II, alters respiration in the striatum. To assess the role of striatal dysfunction in the pathology, we selectively inactivated Ndufs4 in the striatal medium spiny neurons (MSNs), which account for over 95% of striatal neurons. Our results show that lack of Ndufs4 in MSNs causes a non-fatal progressive motor impairment without affecting the cognitive function of mice. Furthermore, no inflammatory responses or neuronal loss were observed up to 6 months of age. Hence, complex I deficiency in MSNs contributes to the motor deficits observed in LS, but not to the neural degeneration, suggesting that other neuronal populations drive the plethora of clinical signs in LS

    Resting state cortico-cerebellar functional connectivity networks: a comparison of anatomical and self-organizing map approaches.

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    The cerebellum plays a role in a wide variety of complex behaviors. In order to better understand the role of the cerebellum in human behavior, it is important to know how this structure interacts with cortical and other subcortical regions of the brain. To date, several studies have investigated the cerebellum using resting-state functional connectivity magnetic resonance imaging (fcMRI; Krienen and Buckner, 2009; O'Reilly et al., 2010; Buckner et al., 2011). However, none of this work has taken an anatomically-driven lobular approach. Furthermore, though detailed maps of cerebral cortex and cerebellum networks have been proposed using different network solutions based on the cerebral cortex (Buckner et al., 2011), it remains unknown whether or not an anatomical lobular breakdown best encompasses the networks of the cerebellum. Here, we used fcMRI to create an anatomically-driven connectivity atlas of the cerebellar lobules. Timecourses were extracted from the lobules of the right hemisphere and vermis. We found distinct networks for the individual lobules with a clear division into "motor" and "non-motor" regions. We also used a self-organizing map (SOM) algorithm to parcellate the cerebellum. This allowed us to investigate redundancy and independence of the anatomically identified cerebellar networks. We found that while anatomical boundaries in the anterior cerebellum provide functional subdivisions of a larger motor grouping defined using our SOM algorithm, in the posterior cerebellum, the lobules were made up of sub-regions associated with distinct functional networks. Together, our results indicate that the lobular boundaries of the human cerebellum are not necessarily indicative of functional boundaries, though anatomical divisions can be useful. Additionally, driving the analyses from the cerebellum is key to determining the complete picture of functional connectivity within the structure

    Loss of mitochondrial Ndufs4 in striatal medium spiny neurons mediates progressive motor impairment in a mouse model of leigh syndrome

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    Altres ajuts: Juan del la Cierva (IJCI-2015-24576)Inability of mitochondria to generate energy leads to severe and often fatal myoencephalopathies. Among these, Leigh syndrome (LS) is one of the most common childhood mitochondrial diseases; it is characterized by hypotonia, failure to thrive, respiratory insufficiency and progressive mental and motor dysfunction, leading to early death. Basal ganglia nuclei, including the striatum, are affected in LS patients. However, neither the identity of the affected cell types in the striatum nor their contribution to the disease has been established. Here, we used a mouse model of LS lacking Ndufs4, a mitochondrial complex I subunit, to confirm that loss of complex I, but not complex II, alters respiration in the striatum. To assess the role of striatal dysfunction in the pathology, we selectively inactivated Ndufs4 in the striatal medium spiny neurons (MSNs), which account for over 95% of striatal neurons. Our results show that lack of Ndufs4 in MSNs causes a non-fatal progressive motor impairment without affecting the cognitive function of mice. Furthermore, no inflammatory responses or neuronal loss were observed up to 6 months of age. Hence, complex I deficiency in MSNs contributes to the motor deficits observed in LS, but not to the neural degeneration, suggesting that other neuronal populations drive the plethora of clinical signs in LS

    Reverberation Mapping of the Kepler-Field AGN KA1858+4850

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    KA1858+4850 is a narrow-line Seyfert 1 galaxy at redshift 0.078 and is among the brightest active galaxies monitored by the Kepler mission. We have carried out a reverberation mapping campaign designed to measure the broad-line region size and estimate the mass of the black hole in this galaxy. We obtained 74 epochs of spectroscopic data using the Kast Spectrograph at the Lick 3-m telescope from February to November of 2012, and obtained complementary V-band images from five other ground-based telescopes. We measured the H-beta light curve lag with respect to the V-band continuum light curve using both cross-correlation techniques (CCF) and continuum light curve variability modeling with the JAVELIN method, and found rest-frame lags of lag_CCF = 13.53 (+2.03, -2.32) days and lag_JAVELIN = 13.15 (+1.08, -1.00) days. The H-beta root-mean-square line profile has a width of sigma_line = 770 +/- 49 km/s. Combining these two results and assuming a virial scale factor of f = 5.13, we obtained a virial estimate of M_BH = 8.06 (+1.59, -1.72) x 10^6 M_sun for the mass of the central black hole and an Eddington ratio of L/L_Edd ~ 0.2. We also obtained consistent but slightly shorter emission-line lags with respect to the Kepler light curve. Thanks to the Kepler mission, the light curve of KA1858+4850 has among the highest cadences and signal-to-noise ratios ever measured for an active galactic nucleus; thus, our black hole mass measurement will serve as a reference point for relations between black hole mass and continuum variability characteristics in active galactic nuclei

    Skeletal Muscle Undergoes Fiber Type Metabolic Switch Without Myosin Heavy Chain Switch in Response to Defective Fatty Acid Oxidation

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    OBJECTIVE: Skeletal muscle is a heterogeneous and dynamic tissue that adapts to functional demands and substrate availability by modulating muscle fiber size and type. The concept of muscle fiber type relates to its contractile (slow or fast) and metabolic (glycolytic or oxidative) properties. Here, we tested whether disruptions in muscle oxidative catabolism are sufficient to prompt parallel adaptations in energetics and contractile protein composition. METHODS: Mice with defective mitochondrial long-chain fatty acid oxidation (mLCFAO) in the skeletal muscle due to loss of carnitine palmitoyltransferase 2 (Cpt2(Sk−/−)) were used to model a shift in muscle macronutrient catabolism. Glycolytic and oxidative muscles of Cpt2(Sk−/−) mice and control littermates were compared for the expression of energy metabolism-related proteins, mitochondrial respiratory capacity, and myosin heavy chain isoform composition. RESULTS: Differences in bioenergetics and macronutrient utilization in response to energy demands between control muscles were intrinsic to the mitochondria, allowing for a clear distinction of muscle types. Loss of CPT2 ablated mLCFAO and resulted in mitochondrial biogenesis occurring most predominantly in oxidative muscle fibers. The metabolism-related proteomic signature of Cpt2(Sk−/−) oxidative muscle more closely resembled that of glycolytic muscle than of control oxidative muscle. Respectively, intrinsic substrate-supported mitochondrial respiration of CPT2 deficient oxidative muscles shifted to closely match that of glycolytic muscles. Despite this shift in mitochondrial metabolism, CPT2 deletion did not result in contractile-based fiber type switching according to myosin heavy chain composition analysis. CONCLUSION: The loss of mitochondrial long-chain fatty acid oxidation elicits an adaptive response involving conversion of oxidative muscle toward a metabolic profile that resembles a glycolytic muscle, but this is not accompanied by changes in myosin heavy chain isoforms. These data suggest that shifts in muscle catabolism are not sufficient to drive shifts in the contractile apparatus but are sufficient to drive adaptive changes in metabolic properties
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