Monitoring neuronal electrical activity using fluorescent protein-based voltage sensors has been limited by small response magnitudes and slow kinetics of existing probes. Here we report the ...development of a fluorescent protein voltage sensor, named ArcLight, and derivative probes that exhibit large changes in fluorescence intensity in response to voltage changes. ArcLight consists of the voltage-sensing domain of Ciona intestinalis voltage-sensitive phosphatase and super ecliptic pHluorin that carries the point mutation A227D. The fluorescence intensity of ArcLight A242 decreases by 35% in response to a 100mV depolarization when measured in HEK293 cells, which is more than five times larger than the signals from previously reported fluorescent protein voltage sensors. We show that the combination of signal size and response speed of these new probes allows the reliable detection of single action potentials and excitatory potentials in individual neurons and dendrites.
► CiVS-based FP voltage sensors improved by A227D mutation in super ecliptic pHluorin ► Optogenetic visualization of single action potentials and subthreshold events
Jin et al. report a technique for imaging single action potentials and subthreshold electrical events in neurons with a novel fluorescent protein voltage probe.
Humans and other animals can recognize an odorant as the same over a range of odorant concentrations. It remains unclear whether the olfactory bulb, the brain structure that mediates the first stage ...of olfactory information processing, participates in generating this perceptual concentration invariance. Olfactory bulb glomeruli are regions of neuropil that contain input and output processes: olfactory receptor neuron nerve terminals (input) and mitral/tufted cell apical dendrites (output). Differences between the input and output of a brain region define the function(s) carried out by that region. Here we compare the activity signals from the input and output across a range of odorant concentrations. The output maps maintain a relatively stable representation of odor identity over the tested concentration range, even though the input maps and signals change markedly. These results provide direct evidence that the mammalian olfactory bulb likely participates in generating the perception of concentration invariance of odor quality.Humans and animals recognize an odorant across a range of odorant concentrations, but where in the olfactory processing pathway this invariance is generated is unclear. By measuring and comparing olfactory bulb outputs to inputs, the authors show that the olfactory bulb participates in generating the perception of odorant concentration invariance.
ArcLight, a genetically encoded fluorescent protein voltage probe with a large ΔF/ΔV, is a fusion between the voltage sensing domain of the Ciona instestinalis voltage sensitive phosphatase and super ...ecliptic pHluorin carrying a single mutation (A227D in the fluorescent protein). Without this mutation the probe produces only a very small change in fluorescence in response to voltage deflections (∼ 1%). The large signal afforded by this mutation allows optical detection of action potentials and sub-threshold electrical events in single-trials in vitro and in vivo. However, it is unclear how this single mutation produces a probe with such a large modulation of its fluorescence output with changes in membrane potential. In this study, we identified which residues in super ecliptic pHluorin (vs eGFP) are critical for the ArcLight response, as a similarly constructed probe based on eGFP also exhibits large response amplitude if it carries these critical residues. We found that D147 is responsible for determining the pH sensitivity of the fluorescent protein used in these probes but by itself does not result in a voltage probe with a large signal. We also provide evidence that the voltage dependent signal of ArcLight is not simply sensing environmental pH changes. A two-photon polarization microscopy study showed that ArcLight's response to changes in membrane potential includes a reorientation of the super ecliptic pHluorin. We also explored different changes including modification of linker length, deletion of non-essential amino acids in the super ecliptic pHluorin, adding a farnesylation site, using tandem fluorescent proteins and other pH sensitive fluorescent proteins.
Biomarkers in nonalcoholic fatty liver disease Neuman, Manuela G; Cohen, Lawrence B; Nanau, Radu M
Canadian journal of gastroenterology & hepatology,
12/2014, Letnik:
28, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Nonalcoholic fatty liver disease (NAFLD) is a chronic liver condition characterized by insulin resistance, type 2 diabetes and fat accumulation in the liver that may cause hepatic inflammation and ...progressive scarring leading to nonalcoholic steatohepatitis (NASH) and irreversible liver damage (cirrhosis). As a result, there has been increased recognition of the need to assess and closely monitor individuals for risk factors of components of NAFLD and NASH, as well as the severity of these conditions using biomarkers.
To review the biomarkers used to diagnose and define the severity of NAFLD and NASH.
A comprehensive PubMed and Google Scholar literature search was performed using the terms "non-alcoholic fatty liver disease", "non-alcoholic steatohepatitis", as well as the name of each biomarker known to be used. Articles indexed between 2004 and 2014 were used. Each author read the publications separately and the results were discussed.
Biomarkers offer a potential prognostic or diagnostic indicator for disease manifestation, progression or both. Serum biomarkers, including total cholesterol, triglycerides, insulin resistance and C-peptide, have been used for many years. Emerging biomarkers, such as apolipoprotein A1, apolipoprotein B, leptin, adiponectin, free fatty acids, ghrelin and tumour necrosis factor-alpha, have been proposed as tools that could provide valuable complementary information to that obtained from traditional biomarkers. Moreover, markers of cell death and mitochondrial dysfunction (cytokeratins) represent powerful predictors of risk. For biomarkers to be clinically useful in accurately diagnosing and treating disorders, age-specific reference intervals that account for differences in sex and ethnic origin are a necessity.
The present review attempts to provide a comprehensive analysis of the emerging risk biomarkers of NAFLD and NASH, and to use the clinical significance and analytical considerations of each biomarker pointing out sentinel features of disease progression.
This article provides an overview of FDA's regulatory processes for drug development and approval, and the estimated costs associated with the development of a drug, and also examines the issues and ...challenges facing the FDA in the near future.
A literature search was performed using MEDLINE to summarize the current FDA drug approval processes and future directions. MEDLINE was further utilized to search for all cost analysis studies performed to evaluate the pharmaceutical industry R&D productivity and drug development cost estimates.
While the drug approval process remains at high risk and spans over multiple years, the FDA drug review and approval process has improved, with the median approval time for new molecular drugs been reduced from 19 months to 10 months. The overall cost to development of a drug remains quite high and has been estimated to range from $868M to $1,241M USD. Several new laws have been enacted, including the FDA Safety and Innovation Act (FDASIA) of 2013, which is designed to improve the drug approval process and enhance access to new medicines.
The FDA's improved processes for drug approval and post-market surveillance have achieved the goal of providing patients with timely access to effective drugs while minimizing the risk of drug-related harm. The FDA drug approval process is not without controversy, as a number of well-known gastroenterology drugs have been withdrawn from the US market over the past few years. With the approval of the new FDASIA law, the FDA will continue to improve their processes and, working together with the ACG through the FDA-Related Matters Committee, continue to develop safe and effective drugs for our patients.
Background The New York Heart Association (NYHA) classification has served as a fundamental tool for risk stratification of heart failure (HF) and determines clinical trial eligibility and candidacy ...for drugs and devices. However, its ability to adequately stratify risk is unclear. Methods and Results To compare NYHA class with objective assessments and survival in patients with HF, we performed secondary analyses of 4 multicenter National Institutes of Health-funded HF clinical trials that included patients classified as NYHA class II or III: TOPCAT (Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist), DIG (The Effect of Digoxin on Mortality and Morbidity in Patients With Heart Failure), HF-ACTION (Efficacy and Safety of Exercise Training in Patients With Chronic Heart Failure), and GUIDE-IT (Guiding Evidence-Based Therapy Using Biomarker Intensified Treatment in Heart Failure). Twenty-month cumulative survival was compared between classes using Kaplan-Meier curves and the log rank test. NT-proBNP (N-terminal pro-B-type natriuretic peptide), Kansas City Cardiomyopathy Questionnaire (KCCQ) scores, 6-minute walk distances, left ventricular ejection fraction, and cardiopulmonary test parameters were compared using Wilcoxon rank sum tests and percentage overlap using kernel density estimations. Cumulative mortality varied significantly across NYHA classes and HF clinical trials (likelihood ratio,
<0.001). Mortality at 20 months for NYHA class II ranged from 7% for patients in HF-ACTION to 15% in GUIDE-IT, whereas mortality for NYHA class III ranged from 12% in TOPCAT to 26% in GUIDE-IT. There was substantial percentage overlap in values for NT-proBNP levels (79% and 69%), KCCQ scores (63% and 54%), 6-minute walk distances (63% and 54%), and left ventricular ejection fraction (88% and 83%). Similarly, there was substantial overall in values for minute ventilation-carbon dioxide production relationship (71%), maximal oxygen uptake (54%), and exercise duration (53%). Conclusions The NYHA system poorly discriminates HF patients across the spectrum of functional impairment. These findings raise important questions about the need for improved phenotyping of these patients to facilitate risk stratification and response to interventions.
Historically, safety in the gastrointestinal (GI) endoscopy unit has focused on infection control, particularly around the reprocessing of endoscopes. Two highly publicized outbreaks where the ...transmission of infectious agents were related to GI endoscopy have highlighted the need to address potential gaps along the endoscopy care continuum that could impact patient safety.
The purpose of the American College of Clinical Pharmacy (ACCP) is to advance human health by extending the frontiers of clinical pharmacy. Consistent with this mission and its core values, ACCP is ...committed to ensuring that clinical pharmacists possess the knowledge, skills, attitudes, and behaviors necessary to deliver comprehensive medication management (CMM) in team-based, direct patient care environments. These components form the basis for the core competencies of a clinical pharmacist and reflect the competencies of other direct patient care providers. This paper is an update to a previous ACCP document and includes the expectation that clinical pharmacists be competent in six essential domains: direct patient care, pharmacotherapy knowledge, systems-based care and population health, communication, professionalism, and continuing professional development. Although these domains align with the competencies of physician providers, they are specifically designed to better reflect the clinical pharmacy expertise required to provide CMM in patient-centered, team-based settings. Clinical pharmacists must be prepared to complete the education and training needed to achieve these competencies and must commit to ongoing efforts to maintain competence through ongoing professional development. Collaboration among stakeholders will be needed to ensure that these competencies guide clinical pharmacists' professional development and evaluation by educational institutions, postgraduate training programs, professional societies, and employers.
Chronic liver diseases may cause inflammation and progressive scarring, over time leading to irreversible hepatic damage (cirrhosis). As a result, the need to assess and closely monitor individuals ...for risk factors of components of matrix deposition and degradation, as well as the severity of the fibrosis using biomarkers, has been increasingly recognized.
Our aim is to review the use of biomarker for diagnosing and defining the severity of liver fibrosis.
A systematic literature review was done using the terms “hyaluronic acid” and “liver fibrosis” as well as the name of each biomarker or algorithm known to be employed. PubMed and Google Scholar were searched, and English language articles indexed between January 2010 and October 2014 in which HA was used as a marker of liver fibrosis were retrieved, regardless of the underlying liver disease. Each author read the publications separately and the results were analyzed and discussed.
Biomarkers offer a potential prognostic or diagnostic indicator for disease manifestation, progression, or both. Serum biomarkers, including HA, have been used for many years.
Emerging biomarkers such as metalloproteinases have been proposed as tools that provide valuable complementary information to that obtained from traditional biomarkers. Moreover, markers of extracellular matrix degradation provide powerful predictions of risk. In order for biomarkers to be clinically useful in accurately diagnosing and treating disorders, age-specific reference intervals that account for differences in gender and ethnic origin are a necessity.
This review attempts to provide a comprehensive analysis of the emerging risk biomarkers of liver fibrosis and to describe the clinical significance and analytical considerations of each biomarker pointing out sentinel features of disease progression.
•Hyaluronic acid (HA) is a non-invasive biomarker, used alone or in combination with other markers to determine the degree of fibrosis.•HA sensitivity and specificity limit its use.•Different algorithms in which HA is part of the equation are suggested for fibrosis of liver illnesses.•Liver biopsy remains the gold standard of histological activity index/ inflammation and fibrosis in diagnosis of liver damage.•HA and other matrix markers should be employed to monitor the liver fibrosis in time and/or during therapies.
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