GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Document type
Language
  • 1
    Online Resource
    Online Resource
    Milton :CRC Press LLC,
    Keywords: Machine learning. ; Electronic books.
    Description / Table of Contents: This book is designed to introduce the concept of advanced business analytic approaches and would the first to cover the gamut of how to use the R programming language to apply descriptive, predictive, and prescriptive analytic methodologies for problem solving.
    Type of Medium: Online Resource
    Pages: 1 online resource (484 pages)
    Edition: 1st ed.
    ISBN: 9781000730197
    Series Statement: Chapman and Hall/CRC the R Series
    DDC: 006.3/1
    Language: English
    Note: Cover -- Half Title -- Title Page -- Copyright Page -- Dedication -- Table of Contents -- Preface -- I: Fundamentals -- Chapter 1: Introduction to Machine Learning -- 1.1 Supervised learning -- 1.1.1 Regression problems -- 1.1.2 Classification problems -- 1.2 Unsupervised learning -- 1.3 Roadmap -- 1.4 The data sets -- Chapter 2: Modeling Process -- 2.1 Prerequisites -- 2.2 Data splitting -- 2.2.1 Simple random sampling -- 2.2.2 Stratified sampling -- 2.2.3 Class imbalances -- 2.3 Creating models in R -- 2.3.1 Many formula interfaces -- 2.3.2 Many engines -- 2.4 Resampling methods -- 2.4.1 k-fold cross validation -- 2.4.2 Bootstrapping -- 2.4.3 Alternatives -- 2.5 Bias variance trade-off -- 2.5.1 Bias -- 2.5.2 Variance -- 2.5.3 Hyperparameter tuning -- 2.6 Model evaluation -- 2.6.1 Regression models -- 2.6.2 Classification models -- 2.7 Putting the processes together -- Chapter 3: Feature & -- Target Engineering -- 3.1 Prerequisites -- 3.2 Target engineering -- 3.3 Dealing with missingness -- 3.3.1 Visualizing missing values -- 3.3.2 Imputation -- 3.4 Feature filtering -- 3.5 Numeric feature engineering -- 3.5.1 Skewness -- 3.5.2 Standardization -- 3.6 Categorical feature engineering -- 3.6.1 Lumping -- 3.6.2 One-hot & -- dummy encoding -- 3.6.3 Label encoding -- 3.6.4 Alternatives -- 3.7 Dimension reduction -- 3.8 Proper implementation -- 3.8.1 Sequential steps -- 3.8.2 Data leakage -- 3.8.3 Putting the process together -- II: Supervised Learning -- Chapter 4: Linear Regression -- 4.1 Prerequisites -- 4.2 Simple linear regression -- 4.2.1 Estimation -- 4.2.2 Inference -- 4.3 Multiple linear regression -- 4.4 Assessing model accuracy -- 4.5 Model concerns -- 4.6 Principal component regression -- 4.7 Partial least squares -- 4.8 Feature interpretation -- 4.9 Final thoughts -- Chapter 5: Logistic Regression -- 5.1 Prerequisites. , 5.2 Why logistic regression -- 5.3 Simple logistic regression -- 5.4 Multiple logistic regression -- 5.5 Assessing model accuracy -- 5.6 Model concerns -- 5.7 Feature interpretation -- 5.8 Final thoughts -- Chapter 6: Regularized Regression -- 6.1 Prerequisites -- 6.2 Why regularize? -- 6.2.1 Ridge penalty -- 6.2.2 Lasso penalty -- 6.2.3 Elastic nets -- 6.3 Implementation -- 6.4 Tuning -- 6.5 Feature interpretation -- 6.6 Attrition data -- 6.7 Final thoughts -- Chapter 7: Multivariate Adaptive Regression Splines -- 7.1 Prerequisites -- 7.2 The basic idea -- 7.2.1 Multivariate adaptive regression splines -- 7.3 Fitting a basic MARS model -- 7.4 Tuning -- 7.5 Feature interpretation -- 7.6 Attrition data -- 7.7 Final thoughts -- Chapter 8: K-Nearest Neighbors -- 8.1 Prerequisites -- 8.2 Measuring similarity -- 8.2.1 Distance measures -- 8.2.2 Preprocessing -- 8.3 Choosing k -- 8.4 MNIST example -- 8.5 Final thoughts -- Chapter 9: Decision Trees -- 9.1 Prerequisites -- 9.2 Structure -- 9.3 Partitioning -- 9.4 How deep? -- 9.4.1 Early stopping -- 9.4.2 Pruning -- 9.5 Ames housing example -- 9.6 Feature interpretation -- 9.7 Final thoughts -- Chapter 10: Bagging -- 10.1 Prerequisites -- 10.2 Why and when bagging works -- 10.3 Implementation -- 10.4 Easily parallelize -- 10.5 Feature interpretation -- 10.6 Final thoughts -- Chapter 11: Random Forests -- 11.1 Prerequisites -- 11.2 Extending bagging -- 11.3 Out-of-the-box performance -- 11.4 Hyperparameters -- 11.4.1 Number of trees -- 11.4.2 mtry -- 11.4.3 Tree complexity -- 11.4.4 Sampling scheme -- 11.4.5 Split rule -- 11.5 Tuning strategies -- 11.6 Feature interpretation -- 11.7 Final thoughts -- Chapter 12: Gradient Boosting -- 12.1 Prerequisites -- 12.2 How boosting works -- 12.2.1 A sequential ensemble approach -- 12.2.2 Gradient descent -- 12.3 Basic GBM -- 12.3.1 Hyperparameters. , 12.3.2 Implementation -- 12.3.3 General tuning strategy -- 12.4 Stochastic GBMs -- 12.4.1 Stochastic hyperparameters -- 12.4.2 Implementation -- 12.5 XGBoost -- 12.5.1 XGBoost hyperparameters -- 12.5.2 Tuning strategy -- 12.6 Feature interpretation -- 12.7 Final thoughts -- Chapter 13: Deep Learning -- 13.1 Prerequisites -- 13.2 Why deep learning -- 13.3 Feedforward DNNs -- 13.4 Network architecture -- 13.4.1 Layers and nodes -- 13.4.2 Activation -- 13.5 Backpropagation -- 13.6 Model training -- 13.7 Model tuning -- 13.7.1 Model capacity -- 13.7.2 Batch normalization -- 13.7.3 Regularization -- 13.7.4 Adjust learning rate -- 13.8 Grid search -- 13.9 Final thoughts -- Chapter 14: Support Vector Machines -- 14.1 Prerequisites -- 14.2 Optimal separating hyperplanes -- 14.2.1 The hard margin classifier -- 14.2.2 The soft margin classifier -- 14.3 The support vector machine -- 14.3.1 More than two classes -- 14.3.2 Support vector regression -- 14.4 Job attrition example -- 14.4.1 Class weights -- 14.4.2 Class probabilities -- 14.5 Feature interpretation -- 14.6 Final thoughts -- Chapter 15: Stacked Models -- 15.1 Prerequisites -- 15.2 The Idea -- 15.2.1 Common ensemble methods -- 15.2.2 Super learner algorithm -- 15.2.3 Available packages -- 15.3 Stacking existing models -- 15.4 Stacking a grid search -- 15.5 Automated machine learning -- Chapter 16: Interpretable Machine Learning -- 16.1 Prerequisites -- 16.2 The idea -- 16.2.1 Global interpretation -- 16.2.2 Local interpretation -- 16.2.3 Model-specific vs. model-agnostic -- 16.3 Permutation-based feature importance -- 16.3.1 Concept -- 16.3.2 Implementation -- 16.4 Partial dependence -- 16.4.1 Concept -- 16.4.2 Implementation -- 16.4.3 Alternative uses -- 16.5 Individual conditional expectation -- 16.5.1 Concept -- 16.5.2 Implementation -- 16.6 Feature interactions -- 16.6.1 Concept. , 16.6.2 Implementation -- 16.6.3 Alternatives -- 16.7 Local interpretable model-agnostic explanations -- 16.7.1 Concept -- 16.7.2 Implementation -- 16.7.3 Tuning -- 16.7.4 Alternative uses -- 16.8 Shapley values -- 16.8.1 Concept -- 16.8.2 Implementation -- 16.8.3 XGBoost and built-in Shapley values -- 16.9 Localized step-wise procedure -- 16.9.1 Concept -- 16.9.2 Implementation -- 16.10 Final thoughts -- III: Dimension Reduction -- Chapter 17: Principal Components Analysis -- 17.1 Prerequisites -- 17.2 The idea -- 17.3 Finding principal components -- 17.4 Performing PCA in R -- 17.5 Selecting the number of principal components -- 17.5.1 Eigenvalue criterion -- 17.5.2 Proportion of variance explained criterion -- 17.5.3 Scree plot criterion -- 17.6 Final thoughts -- Chapter 18: Generalized Low Rank Models -- 18.1 Prerequisites -- 18.2 The idea -- 18.3 Finding the lower ranks -- 18.3.1 Alternating minimization -- 18.3.2 Loss functions -- 18.3.3 Regularization -- 18.3.4 Selecting k -- 18.4 Fitting GLRMs in R -- 18.4.1 Basic GLRM model -- 18.4.2 Tuning to optimize for unseen data -- 18.5 Final thoughts -- Chapter 19: Autoencoders -- 19.1 Prerequisites -- 19.2 Undercomplete autoencoders -- 19.2.1 Comparing PCA to an autoencoder -- 19.2.2 Stacked autoencoders -- 19.2.3 Visualizing the reconstruction -- 19.3 Sparse autoencoders -- 19.4 Denoising autoencoders -- 19.5 Anomaly detection -- 19.6 Final thoughts -- IV: Clustering -- Chapter 20: K-means Clustering -- 20.1 Prerequisites -- 20.2 Distance measures -- 20.3 Defining clusters -- 20.4 k-means algorithm -- 20.5 Clustering digits -- 20.6 How many clusters? -- 20.7 Clustering with mixed data -- 20.8 Alternative partitioning methods -- 20.9 Final thoughts -- Chapter 21: Hierarchical Clustering -- 21.1 Prerequisites -- 21.2 Hierarchical clustering algorithms -- 21.3 Hierarchical clustering in R. , 21.3.1 Agglomerative hierarchical clustering -- 21.3.2 Divisive hierarchical clustering -- 21.4 Determining optimal clusters -- 21.5 Working with dendrograms -- 21.6 Final thoughts -- Chapter 22: Model-based Clustering -- 22.1 Prerequisites -- 22.2 Measuring probability and uncertainty -- 22.3 Covariance types -- 22.4 Model selection -- 22.5 My basket example -- 22.6 Final thoughts -- Bibliography -- Index.
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Online Resource
    Online Resource
    Cham :Springer International Publishing AG,
    Keywords: Ebullition. ; Emulsions. ; Heat-Transmission. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (151 pages)
    Edition: 1st ed.
    ISBN: 9783031277733
    Series Statement: Mechanical Engineering Series
    DDC: 536.44
    Language: English
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Online Resource
    Online Resource
    New York :Nova Science Publishers, Incorporated,
    Keywords: Diagnostic imaging. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (110 pages)
    Edition: 1st ed.
    ISBN: 9781634831635
    DDC: 612.8233
    Language: English
    Note: Intro -- MOTOR IMAGERY: EMERGING PRACTICES, ROLE IN PHYSICAL THERAPY AND CLINICAL IMPLICATIONS -- MOTOR IMAGERY: EMERGING PRACTICES, ROLE IN PHYSICAL THERAPY AND CLINICAL IMPLICATIONS -- Library of Congress Cataloging-in-Publication Data -- Contents -- Preface -- Chapter 1: Spinal Neural Function during Motor Imagery -- Abstract -- 1. Introduction -- 2. Excitability of Spinal Neural Function during Several Motor Imagery Tasks Involving Isometric Opponens Pollicis Activity (Suzuki et al., 2013) -- 3. Excitability of Spinal Neural Function by Motor Imagery with Isometric Opponens Pollicis Activity: Influence of Vision during Motor Imagery (NeuroRehabilitation 34:725-729, 2014) -- 4. Excitability of Spinal Neural Function during Motor Imagery in Parkinson's Disease (PD) (Suzuki et al., 2014) -- Conclusion -- References -- Chapter 2: Motor Imagery in Children with Developmental Coordination Disorder -- Abstract -- Introduction -- Developmental Coordination Disorder (DCD) -- Internal Modeling Deficit Hypothesis (IMD) -- Motor Imagery (MI) -- Motor Imagery Studies in DCD -- Implications and Applications -- Conclusion -- References -- Chapter 3: The Potential of Motor Imagery Training in Fall Prevention among the Elderly -- Abstract -- Introduction -- Mentally Representing Action and Motor Imagery -- Motor Imagery Practice -- General Strategies for Motor Imagery Practice -- Conclusion -- References -- Chapter 4: Motor Imagery with Brain- Computer Interface Neurotechnology -- Abstract -- Introduction -- Methods -- Results -- Assessment of Cognitive Functions with Motor Imagery -- Discussion -- Future Outlook -- References -- Chapter 5: Mental Practice: Neurophysiology and Clinical Aspects in Neurorehabilitation -- Abstract -- 1. Motor Imagery and Mental Practice or Motor Imagery Practice. , 2. Neurophysiology: The Motor Imagery- Based Mental Practice Is Similar to Motor Execution -- 3. Emerging Practices -- 4. Role in Physical Therapy -- 5. Clinical Implications -- References -- Index -- Blank Page.
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Online Resource
    Online Resource
    Hauppauge :Nova Science Publishers, Incorporated,
    Keywords: Fructose in human nutrition. ; Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (180 pages)
    Edition: 1st ed.
    ISBN: 9781620811917
    Series Statement: Nutrition and Diet Research Progress
    Language: English
    Note: Intro -- FRUCTOSE -- FRUCTOSE -- CONTENTS -- PREFACE -- UNHEALTHY DIET INTAKE DURING THE PERI-NATAL AND ADULT PERIODS: DETRIMENTAL NEUROENDOCRINE AND METABOLIC EFFECTS -- ABSTRACT -- 1. INTRODUCTION -- 2. MATERIALS AND METHODS -- 2.1. Experimental Design I: Impact of FRD Consumption by the Lactating Mother on Metabolic and Neuroendocrine Functions in the First Male Offspring in the Adult Age -- 2.1.1. Animals and Diets -- 2.1.2. Studies Performed in Basal Condition -- 2.1.3. Glucose Tolerance Test (GTT) -- 2.1.4. Hypothalamic Sensitivity to Leptin -- 2.1.5. Morphological Characteristics of the AT -- 2.1.6. Isolation and Incubation of RPAT Cells -- 2.1.7. Measurement of Peripheral Biomarkers -- 2.1.8. Tissue RNA Isolation and Real-Time PCR -- 2.1.9. Medial Basal Hypothalamus: Western Blot Analysis -- 2.2. Experimental Design II: Impact of FRD Consumption by the Naive Adult Male Rat -- 2.2.1. Animals and Diets -- 2.2.2. Chemicals -- 2.2.3. Peripheral Metabolite Measurements -- 2.2.4. Glucose Tolerance Test (GTT) -- 2.2.5. Histological Studies in AAT -- 2.2.6. Enzymatic Antioxidant Activities and Lipid Soluble Antioxidants in AAT -- 2.2.7. Thiobarbituric acid Reactive Substances (TBARS) Measurement -- 2.2.8. Lipid Composition in AAT -- 2.2.9. Leptin Release by AAT -- 2.2.10. Gene Expression in AAT -- 3. STATISTICAL ANALYSIS -- 4. RESULTS -- 4.1. Experiment 1: FRD Administration to Normal Lactating Mothers: Neuroendocrine and Metabolic Impact on the First Adult Male Offspring -- 4.1.1. Body Weight, Energy Intake and Peripheral Metabolites in Lactating Mothers -- 4.1.2. Impact of FRD Administration to Lactating Mothers upon Offspring BW, Food Intake and Peripheral Biomarkers -- 4.1.3. Peripheral Adipokine Profile in 60 Day-old Male CD and FRD Rats -- 4.1.4. GTT in Adult Male Offspring from CD or FRD Lactating Mothers. , 4.1.5. Adult Offspring RPAT: Morphological Characteristics and Function -- 4.1.6. Hypothalamic Circuitry Controlling Food Intake in Adult Male Rats -- 4.1.7. Leptin Sensitivity in the CD and FRD Offspring -- 4.2. Experiment II: Effect of Short-Time FRD Administration to Naive Adult Male Rats -- 4.2.1. Dietary Intake, BW and Peripheral Biomarkers in Adult CD and FRD Male Rats -- 4.2.2. FRD-induced Modifications in AAT Mass and Adipocyte Characteristics -- 4.2.3. Impact of FRD on AAT FA Composition/Release and Redox State -- 4.2.4. Adipokines, IRS-1 and IRS-2 mRNAs Expressions in AAT Pads -- 4.2.5. In Vitro Leptin Secretion by Isolated Adipocytes from CD and FRD Rats -- 5. DISCUSSION -- 5.1. Detrimental Long-term Effect of Feeding Lactating Mothers with a FRD upon the Offspring's Health -- 5.2. FRD Administration to Adult Rats and Adiposity Dysfunction -- CONCLUSION -- ACKNOWLEDGMENT -- REFERENCES -- HIGH-FRUCTOSE CONSUMPTION AND METABOLIC DISEASES -- ABSTRACT -- INTRODUCTION -- BIOCHEMICAL CHARACTERISTICS -- SOURCES OF FRUCTOSE -- FRUCTOSE CONSUMPTION -- METABOLIC ASPECTS OF FRUCTOSE -- Intestinal absorption -- Hepatic Metabolism -- First Steps of Fructose and Glucose Metabolism -- Metabolic Fate of Triose-P from Fructose -- Endogenous Fructose Production -- Ectopic Lipid Deposition -- FRUCTOSE AND EXERCISE -- EFFECTS OF DIETARY FRUCTOSE -- Dyslipidemia -- Obesity and Fructose -- Uric acid and Fructose -- Hypertension and Fructose -- Metabolic Syndrome / Insulin Resistance / Diabetes -- CONCLUSION -- REFERENCES -- FRUCTOSE AND NON-ALCOHOLIC FATTY LIVER DISEASE -- ABSTRACT -- INTRODUCTION -- FRUCTOSE CATABOLISM IN THE LIVER -- FRUCTOSE CONSUMPTION AND ITS IMPACT ON BODY MASS -- EFFECT OF FRUCTOSE ON INSULIN SENSITIVITY: -- IMPACT OF FRUCTOSE ON LEPTIN SIGNALING -- IMPACT OF FRUCTOSE ON GHRELIN SECRETION. , Fructose Consumption and Hepatic Inflammation -- HIGH FRUCTOSE CONSUMPTION AND CARDIOVASCULAR DISEASE -- ASSOCIATION OF FRUCTOSE CONSUMPTION WITH NON-ALCOHOLIC FATTY LIVER DISEASE -- MECHANISTIC INSIGHT INTO FRUCTOSE-INDUCED FATTY LIVER DISEASE -- CONCLUSION -- ACKNOWLEGMENT -- REFERENCES -- DETRIMENTAL EFFECTS OF EXCESSIVE FRUCTOSE INGESTION ON MEMORY AND OTHER BRAIN FUNCTIONS -- ABSTRACT -- INTRODUCTION -- PERIPHERAL EFFECTS -- CENTRAL EFFECTS -- POSSIBLE MECHANISMS -- PHYSIOLOGICAL RELEVANCE -- CONCLUSION -- REFERENCES -- ROLE OF FRUCTOSE IN BODY FUNCTIONS: AN OVERVIEW -- ABSTRACT -- INTRODUCTION -- Fructose Synthesis -- SPECIFIC FUNCTION OF FRUCTOSE -- Health Implication of Fructose -- Fructose and Insulin Resistance -- Fructose and Diabetes Mellitus -- Fructose and Obesity -- Fructose and Non Alcoholic Fatty Liver (NAFLD) -- Fructose and Metabolic Syndrome -- Fructose and Uric Acid -- Fructose, Advanced Glycation End-Products, and Aging -- Functional Bowel Disturbances -- CONCLUSION -- REFERENCES -- FRUCTOSE FACILITATES ALCOHOL METABOLISM -- DEFINITION, DISCOVERY AND PROBLEMS OF ALCOHOL -- ALCOHOL PHARMACOKINETICS -- The Oxidative Metabolism of Ethanol -- BIOCHEMICAL BASIS OF THE METABOLIC CONSEQUENCES OF ALCOHOL -- ALCOHOLISM AND RELATED PROBLEMS -- Clinical Presentations of Alcoholism -- TREATMENT OF ALCOHOL-INDUCED PROBLEMS -- FRUCTOSE ACCELERATES BLOOD ETHANOL ELIMINATION RATE (BEER) -- Mechanisms of the Stimulatory Effect of Fructose on Blood Ethanol Elimination Rate (BEER) -- Challenges of the "Fructose Effect" -- HONEY AND ALCOHOL METABOLISM -- REFERENCES -- FRUCTOSE AND THE CONTROL OF FOOD INTAKE -- ABSTRACT -- INTRODUCTION -- Fructose and Obesity Animal Models -- Sugar Solution Access and the Control of Food Intake -- The 11 HSD Hypothesis and Fructose -- mRNA in Liver and Mesenteric Adipose 11β-HSD-1 mRNA. , Sugar Solutions and the Hypothalamus -- Do Different Sugars Affect the Controls of Intake Differently? -- CONCLUSION -- ACKNOWLEDGMENT -- REFERENCES -- ABBREVIATIONS -- EFFECT OF FRUCTOSE ON HEALTH -- ABSTRACT -- INTRODUCTION -- BENEFICIAL EFFECTS OF FRUCTOSE -- Lactulose Stimulates the Growth of Health-Promoting Bacteria in the Gastrointestinal Tract, and Inhibits Growth of Pathogenic Bacteria -- Dietary Fructooligosaccharides and Potential Benefits on Health -- Calcium Fructoborate Reduces Exacerbated Cellular Immune Responses Induced by Fusarium Toxins -- DELETERIOUS EFFECTS OF FRUCTOSE -- The Role of Fructose-Enriched Diets in Mechanisms of Nonalcoholic Fatty Liver Disease -- Fructose: A Highly Lipogenic Nutrient Implicated in Insulin Resistance, Hepatic Steatosis, and the Metabolic Syndrome -- Fructose-Induced Increase in Ethanol Metabolism and the Risk of Syndrome X -- Metabolic and Behavioural Effects of Sucrose and Fructose/Glucose Drinks -- Fructose and Changes in Triglyceride or Body Weight -- A High-Fructose Diet Worsens Eccentric Left Ventricular Hypertrophy in Experimental Volume Overload -- Fructose and Hypertension -- Nutrition and Alzheimer's Disease: The Detrimental Role of a High Carbohydrate Diet -- Increased Fructose Intake as a Risk Factor for Dementia -- Aqueous Extract of Globularia Alypum Decreases Hypertriglyceridemia and Ameliorates Oxidative Status of the Muscle, Kidney, and Heart in Rats Fed a High-Fructose Diet -- Grape Seed Extract Supplementation Prevents High-Fructose Diet-Induced Insulin Resistance in Rats By Improving Insulin and Adiponectin Signalling Pathways -- Effects of a Maternal Diet Supplemented with Chocolate and Fructose Beverage during Gestation and Lactation on Rat Dams and their Offspring. , Maternal Fructose Intake during Pregnancy and Lactation Alters Placental Growth and Leads to Sex-Specific Changes in Fetal and Neonatal Endocrine Function -- DISCUSSION -- REFERENCES -- MAMMALIAN TRIOKINASE AND DIHYDROXYACETONE KINASE ARE THE SAME ENZYME -- ABSTRACT -- INTRODUCTION: FRUCTOSE METABOLISM -- THE REPORTED PROPERTIES OF TRIOKINASE -- DIHYDROXYACETONE KINASE -- "TRIOKINASE" IS THE SAME ENZYME AS DIHYDROXYACETONE KINASE -- CONCLUSION -- REFERENCES -- INDEX.
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 92 (2005), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Neuroinflammation is associated with a variety of CNS pathologies. Levels of tumor necrosis factor-alpha (TNF-α), a major proinflammatory cytokine, as well as extracellular ATP, are increased following various CNS insults. Here we report on the relationship between ATP/P2 purinergic receptor activation and lipopolysaccharide (LPS)-induced TNF-α release from primary cultures of rat cortical astrocytes. Using ELISA, we confirmed that treatment with LPS stimulated the release of TNF-α in a concentration and time dependent manner. ATP treatment alone had no effect on TNF-α release. LPS-induced TNF-α release was attenuated by 1 mm ATP, a concentration known to activate P2X7 receptors. Consistent with this, 3′-O-(4-Benzoyl)benzoyl-ATP (BzATP), a P2X7 receptor agonist, also attenuated LPS-induced TNF-α release. This reduction in TNF-α release was not due to loss of cell viability. Adenosine and 2-chloroadenosine were ineffective, suggesting that attenuation of LPS-induced TNF-α release by ATP was not due to ATP breakdown and subsequent activation of adenosine/P1 receptors. Interestingly, treatment of astrocyte cultures with 10 µm or 100 µm ATP potentiated TNF-α release induced by a submaximal concentration of LPS. UTP and 2methylthioADP (2-MeSADP), P2Y receptor agonists, also enhanced this LPS-induced TNF-α release. Our observations demonstrate opposing effects of ATP/P2 receptor activation on TNF-α release, i.e. P2X receptor activation attenuates, whereas P2Y receptor activation potentiates TNF-α release in LPS-stimulated astrocytes. These observations suggest a mechanism whereby astrocytes can sense the severity of damage in the CNS via ATP release from damaged cells and can modulate the TNF-α mediated inflammatory response depending on the extracellular ATP concentration and corresponding type of astrocyte ATP/P2 receptor activated.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Immunology 21 (2003), S. 713-758 
    ISSN: 0732-0582
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology , Medicine
    Notes: Abstract The T helper lymphocyte is responsible for orchestrating the appropriate immune response to a wide variety of pathogens. The recognition of the polarized T helper cell subsets Th1 and Th2 has led to an understanding of the role of these cells in coordinating a variety of immune responses, both in responses to pathogens and in autoimmune and allergic disease. Here, we discuss the mechanisms that control lineage commitment to the Th1 phenotype. What has recently emerged is a rich understanding of the cytokines, receptors, signal transduction pathways, and transcription factors involved in Th1 differentiation. Although the picture is still incomplete, the basic pathways leading to Th1 differentiation can now be understood in in vitro and a number of infection and disease models.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Changes in the mRNA levels of two Mycobacterium tuberculosis genes (fbpB known as antigen 85B, and hspX known as Acr) were studied in infected human monocytes. Antigen 85B is an enzyme involved in cell wall biosynthesis and is also a major target of the immune response. Acr is a stress protein believed to be involved in the bacillary response to adverse conditions and in non-replicating persistence. During the first 24 h of intracellular infection, the intramonocyte 85B mRNA level increased 54-fold (P = 0.00001) and 14.6 times in comparison with the 16S ribosomal rRNA. In contrast, the Acr mRNA fell 14.3 times. Although monocyte cytokine production was very variable, the 24 h secretion of tumour necrosis factor (TNF)-α correlated with the 85B−16S RNA ratio at 24 h (r = 0.77, Pcorr 〈 0.01). Furthermore, the addition of exogenous TNF-α to cultures was associated with a twofold increase in the 85B−16S ratio and, conversely, neutralization of endogenous TNF-α reduced the ratio. As antigen 85B also induces TNF-α, the positive feedback implied by our findings suggests a previously unsuspected role for this protein in the immunopathogenesis of tuberculosis.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Whether the presence of abnormal PR before selective slow pathway ablation for AV node reentrant tachycardia increased the risk of complete heart block remains controversial. We report our experience in seven patients with prolonged PR intervals undergoing catheter ablation for AV reentry tachycardia. Their mean age was 66 ± 12 years; four patients were female and three were male. RF ablation was performed using an anatomically guided stepwise approach. In six patients, common type AV node reentry was induced and uncommon type was observed in the remaining patient. In all seven patients, successful selective slow pathway ablation was associated with no occurrence of complete heart block and was followed by shortening of the AH interval in five patients. In all seven patients, successful ablation was achieved at anterior sites (M1 in two patients and M2 in five patients). Despite AH shortening after ablation, the 1:1 AV conduction was prolonged after elimination of the slow pathway, excluding either sympathetic tone activation or parasympathetic denervation. In conclusion, selective slow pathway ablation can be performed safely in the majority of patients with prolonged PR interval before the procedure. Because successful ablation is achieved at anterior sites in most patients, careful selection and monitoring of catheter position is required.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: ICD and Sedation. Implantation of implantable cardioverter defibrillators (ICDs) in the electrophysiology (EP) laboratory has been shown to be safe. However, general endotracheal anesthesia and/or administration of sedatives is mostly performed by anesthesiologists. In 53 patients undergoing ICD implantation in the EP laboratory, we prospectively assessed whether deep sedation without endotracheal intubation can be administered by nursing personnel under medical supervision. The mean patient age was 67 ± 7 years, and the mean ejection fraction was 32 ± 8%. All ICDs were placed in the abdomen requiring lead tunneling. Patients were monitored with pulse oximetry and noninvasive blood pressure recordings. The level of consciousness and vital signs were evaluated at 5-minute intervals. Deep sedation was induced with phenergan and midazolam and maintained with either meperidine or fentanyl. The mean doses given were as follows: phenergan 0.33 ± 0.15 mg/kg, midazolam 0.05 ± 0.03 mg/kg, meperidine 0.46 ± 0.10 mg/kg per hour, and fentanyl 1.94 ± 0.71 μg/kg per hour. None of the patients required intubation during or after the procedure. No death occurred and no patient had any recollection of the procedure. In three patients, O2 desaturation was easily managed by transient reversion of the effects of meperidine or fentanyl with naloxone. No patient experienced prolonged hospitalization after the implant (mean 2.4 ± 0.5 days). In conclusion: (1) adequate sedation for ICD implantation and testing can be administered safely by nursing staff in the EP lab; (2) optimum sedation protocols should include drugs easy to reverse in case of excessive respiratory depression; and (3) this may represent a more cost-effective approach to ICD implantation.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Several procedures performed in the electrophysiology laboratory (EP lab) require surgical manipulation and are lengthy. Patients undergoing such procedures usually receive general anesthesia or deep sedation administered by an anesthesiologist. In 536 consecutive procedures performed in the EP lab, we assessed the safety and efficacy of deep sedation administered under the direction of an electrophysiologist and in the absence of an anesthetist. Patients were monitored with pulse oximetry, noninvasive blood pressure recordings, and continuous ECGs. The level of consciousness and vital signs were evaluated at 5-minute intervals. Deep sedation was induced in 260 patients using midazolam, phenergan, and meperidine, then maintained with intermittent dosing of meperidine at the following mean doses: midazolam 0.031 ± 0.024 mg/kg; phenergan 0.314 ± 0.179 mg/kg; and meperidine 0.391 ± 0.167 mg/kg per hour. In the remaining 276 patients, deep sedation was induced with midazolam and fentanyl and maintained with a continuous infusion of fentanyl at a mean dose of 2.054 ± 1.43 μg/kg per hour. Fourteen patients experienced a transient reduction in oxygen saturation that was readily reversed following administration of naloxone. An additional 11 patients desaturated secondary to partial airway obstruction, which resolved after repositioning the head and neck. Fourteen patients experienced hypotension with fentanyl. All but one returned to baseline blood pressures following an infusion of normal saline. No patient required intubation and no death occurred. Only three patients had recollection of periprocedure events. No patient remembered experiencing pain with the procedure. Hospital stays were not prolonged as a result of the sedation used. In conclusion: (1) deep sedation during EP procedures can be administered safely under the guidance of the electrophysiologist without an anesthetist present; (2) the drugs used should be readily reversible in case of respiratory depression; and (3) this approach may reduce the overall cost of the procedures in the EP lab, maintaining adequate patient comfort.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...