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The Ischemic Penumbra: Still the Target for Stroke Therapies?

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196357 Year: Pages: 69 DOI: 10.3389/978-2-88919-635-7 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Neurology
Added to DOAB on : 2016-08-16 10:34:25
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The ischemic penumbra was initially defined by Symon, Lassen and colleagues in the 1970s as an area of brain tissue with inadequate blood flow to maintain electric activity of neurons but adequate blood flow to preserve the function of the ion channels. This area of tissue, receiving enough blood to survive but not enough to function, often surrounds or abuts the irreversibly damaged core in ischemic stroke. It was shown that if blood flow could be restored to this area of marginal perfusion, the tissue could survive and function again, and growth of the core could be prevented. Based on seminal PET studies, penumbra or "penumbral tissue" eventually took on a subtly different meaning - the area of brain that is destined to progress to infarct unless blood flow is restored within a particular time window. The penumbra thus became the target for all acute stroke interventions - to preserve viability of the tissue and restore function. New imaging techniques, including diffusion and perfusion MRI and CT perfusion, were developed to rapidly identify individuals with penumbra, who were thought to be the best candidates for aggressive interventions to restore blood flow, particularly beyond the licensed time-window for IV thrombolysis. However, most clinical trials have failed to establish the usefulness of identifying candidates for treatment in this way using pre-specified protocols and primary endpoints. These trials have used different and sometimes unvalidated thresholds of hypoperfusion as well as irreversible infarct and various definitions of significant penumbra (or mismatch between irreversible infarct and hypoperfused, but salvageable tissue), and reanalysis of their data using more refined image processing showed post-hoc positivity. They have also evaluated outcome in a variety of ways, with few studies measuring the direct effect of restoring blood flow on the function of the penumbral tissue. Therefore, important remaining questions include how to define, characterize, and image the penumbra in acute stroke to achieve the greatest reliability and validity for what we want to measure, and whether this concept, so defined, provides an optimal target for stroke therapy using state-of-the-art trial design.

In Vivo Imaging in Pharmacological Research

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452378 Year: Pages: 222 DOI: 10.3389/978-2-88945-237-8 Language: English
Publisher: Frontiers Media SA
Subject: Therapeutics --- Science (General)
Added to DOAB on : 2017-10-13 14:57:01
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The discovery and development of a biological active molecule with therapeutic properties is an ever increasing complex task, highly unpredictable at the early stages and marked, in the end, by high rates of failure. As a consequence, the overall process leading to the production of a successful drug is very costly. The improvement of the net outcome in drug discovery and development would require, amongst other important factors, a good understanding of the molecular events that characterize the disease or pathology in order to better identify likely targets of interest, to optimize the interaction of an active agent (small molecule or macromolecule of natural or synthetic origin) with those targets, and to facilitate the study of the pharmacokinetics, pharmacodynamics and toxicity of an active agent in suitable models and in human subjects. The objective of this Research Topic is to highlight new developments and applications of imaging techniques with the objective of performing pharmacological studies in vivo, in animal models and in humans. In the domain of drug discovery, the pharmacological and biomedical questions constitute the center of attention. In this sense, it is fundamental to keep in mind the strengths and limitations of each analytical or imaging technique. At the end, the judicious application of the technique with the aim of supporting the search for answers to manifold questions arising during a long and painstaking path provides a continuous role for imaging within the complex area of drug discovery and development.

The Chemistry of Imaging Probes

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889455980 Year: Pages: 129 DOI: 10.3389/978-2-88945-598-0 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Chemistry (General)
Added to DOAB on : 2019-01-23 14:53:43
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Over the past decades, the field of molecular imaging has been rapidly growing involving multiple disciplines such as medicine, biology, chemistry, pharmacology and biomedical engineering. Any molecular imaging procedure requires an imaging probe that is an agent used to visualize, characterize and quantify biological processes in living systems. Such a probe typically consists of an agent that usually produces signal for imaging purpose, a targeting moiety, and a linker connecting the targeting moiety and the signaling agent.Many challenging problems of molecular imaging can be addressed by exploiting the great possibilities offered by modern synthetic organic and coordination chemistry and the powerful procedures provided by conjugation chemistry. Thus, chemistry plays a decisive role in the development of this cutting-edge methodology.Currently, the diagnostic imaging modalities include Magnetic Resonance Imaging (MRI), Computed Tomography (CT), Ultrasound (US), Nuclear Imaging (PET, SPECT), Optical Imaging (OI) and Photoacoustic Imaging (PAI). Each of these imaging modalities has its own advantages and disadvantages, and therefore, a multimodal approach combining two techniques is often adopted to generate complementary anatomical and functional information of the disease. The basis for designing imaging probes for a given application is dictated by the chosen imaging modality, which in turn is dependent upon the concentration and localization profile (vascular, extracellular matrix, cell membrane, intracellular, near or at the cell nucleus) of the target molecule. The development of high-affinity ligands and their conjugation to the targeting vector is also one of the key steps for pursuing efficient molecular imaging probes. Other excellent reviews, text and monographs describe the principles of biomedical imaging, focusing on molecular biology or on the physics behind the techniques. This Research Topic aims to show how chemistry can offer molecular imaging the opportunity to express all its potential.

Targets, Tracers and Translation – Novel Radiopharmaceuticals Boost Nuclear Medicine

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ISBN: 9783039213139 9783039213146 Year: Pages: 214 DOI: 10.3390/books978-3-03921-314-6 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Medicine (General) --- Therapeutics
Added to DOAB on : 2019-12-09 11:49:15
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This is the fourth Special Issue in Pharmaceuticals within the last six years dealing with aspects of radiopharmaceutical sciences. It demonstrates the significant interest and increasing relevance to ameliorate nuclear medicine imaging with PET or SPECT, and also radiotherapeutical procedures.Numerous targets and mechanisms have been identified and have been under investigation over the previous years, covering many fields of medical and clinical research. This development is well illustrated by the articles in the present issue, including 13 original research papers and one review, covering a broad range of actual research topics in the field of radiopharmaceutical sciences.

Keywords

breast cancer --- 68Ga --- GRPR --- NPY(Y1)R --- peptide heterodimers --- PET/CT imaging --- sentinel lymph node --- dextran --- mannose --- 99mTc-radiopharmaceuticals --- glutamate --- metabotropic glutamate receptor subtype 5 --- [18F]PSS232 --- ketamine --- ceftriaxone --- positron emission tomography --- allosteric modulator --- MMPEP --- ABP688 --- pretargeting --- Fusarinine C --- rituximab --- click chemistry --- multimerization --- PET --- gallium-68 --- carbonic anhydrase IX --- girentuximab --- renal cell carcinomas --- 177Lu-radiopharmaceuticals --- radioimmunotherapy --- neuroinflammation --- microglia --- carbon-11 --- radiochemistry --- positron emission tomography --- hypoxia --- radiosensitizer --- benzotriazine-1,4-dioxide (BTDO), benzotriazine-1-monoxide (BTMO), tirapazamine (TPZ), SR 4317 --- radioiodination --- tropomyosin receptor kinase --- positron emission tomography --- neurodegeneration --- oncogenic fusions --- [11C]meta-hydroxyephedrine --- radiosynthesis --- separation --- apparent molar activity --- cholecystokinin-2 receptor --- minigastrin --- molecular imaging --- radiometals --- technetium-99m --- hydrazinonicotinic acid (HYNIC) --- PSMA-617 --- salivary gland uptake --- prostate cancer --- endoradiotherapy --- Chloramine T --- electrophilic radioiodination --- iodine-131 --- Iodo-Gen® --- oxidizing agent --- ?-CIT. --- tumor hypoxia --- PET --- small animal imaging --- azomycin nucleosides --- [18F]FMISO --- bombesin --- gastrin-releasing peptide --- gastrin-releasing peptide receptor --- tumor targeting --- 99mTc-radioligand --- metabolic stability --- neprilysin-inhibition --- phosphoramidon --- n/a --- n/a

High Precision X-Ray Measurements

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ISBN: 9783039213177 9783039213184 Year: Pages: 144 DOI: 10.3390/books978-3-03921-318-4 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Physics (General)
Added to DOAB on : 2019-12-09 16:10:12
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Since their discovery in 1895, the detection of X-rays has had a strong impact on and various applications in several fields of science and human life. Impressive efforts have been made to develop new types of detectors and new techniques, aiming to obtain higher precision both in terms of energy and position. Depending on the applications, solid state detectors, microcalorimeters, and various types of spectrometers currently serve as the best options for spectroscopic and imaging detectors. Recent advancements in micron and meV precision have opened the door for groundbreaking applications in fundamental physics, medical science, astrophysics, cultural heritage, and several other fields. The aim of this Special Issue is to compile an overview, from different communities and research fields, of the most recent developments in X-ray detection and their possible impacts in various sectors, such as in exotic atom measurements, quantum physics studies, XRF, XES, EXAFS, plasma emission spectroscopy, monochromators, synchrotron radiation, telescopes, and space engineering. All the papers included in this Special Issue contribute to emphasizing the importance of X-ray detection in a very broad range of physics topics; most of these topics are covered by the published works, and several others are mentioned in the paper references, providing an interesting and very useful synopsis, from a variety of different communities and research fields, of the most recent developments in X-ray detection and their impact in fundamental research and societal applications.

Molecular Mechanism of Alzheimer's Disease

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ISBN: 9783039214075 9783039214082 Year: Pages: 228 DOI: 10.3390/books978-3-03921-408-2 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology
Added to DOAB on : 2019-12-09 11:49:16
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Alzheimer’s disease (AD) is an age-related neurological disease that affects tens of millions of people, in addition to their carers. Hallmark features of AD include plaques composed of amyloid beta, as well as neurofibrillary tangles of tau protein. However, despite more than a century of study, the cause of Alzheimer’s disease remains unresolved. The roles of amyloid beta and tau are being questioned and other causes of AD are now under consideration. The contributions of researchers, model organisms, and various hypotheses will be examined in this Special Issue.

Keywords

?-secretase --- amyloid beta --- calcium signaling --- drug target discovery --- endoplasmic reticulum --- inositol 1,4,5-trisphosphate receptor --- ion channel --- oxidative stress --- ryanodine receptor --- therapy --- amyloid-? oligomer --- protein aggregation --- A?O receptors --- Alzheimer’s disease --- neurodegeneration --- amyloid ? --- Alzheimer’s disease --- cognitive function --- dairy products --- dementia --- inflammation --- microglia --- Alzheimer’s disease --- yeast --- Tau --- amyloid ? --- ubiquitin --- aggregation --- oligomerization --- prion --- CDK5R1 --- lncRNAs --- Alzheimer’s disease --- miR-15/107 --- NEAT1 --- HOTAIR --- MALAT1 --- heat shock response --- heat shock protein --- Alzheimer’s disease --- beta amyloid --- yeast --- Alzheimer’s disease --- complement receptor 1 --- CR1 length polymorphism --- CR1 density --- complement C3b/C4b receptor --- complement --- dementia --- molecular biology --- neurosciences --- genetic risk --- Alzheimer’s disease --- brain glucose metabolism --- neuronal differentiation --- neuronal degeneration --- Prolyl isomerases --- Pin1 --- type 2 diabetes --- type 3 diabetes --- miR-34c --- dendritic spine --- Alzheimer’s disease --- Alzheimer’s disease --- positron emission tomography (PET) --- magnetic resonance imaging (MRI) --- Alzheimer’s disease --- cystathionine-?-lyase CTH gene --- DNA methylation --- epigenetics --- epigenome-wide association study --- methylome --- methylenetetrahydrofolate reductase MTHFR gene --- nutrition --- S-adenosylmethionine --- vitamin B complex --- Alzheimer’s disease --- sleep disturbance --- sleep fragmentation --- slow-wave sleep --- amyloid beta --- tau --- proteostasis --- default-mode network --- cognitive behavioral therapy for insomnia --- APOE gene --- apolipoprotein E --- DNA methylation --- mild cognitive impairment --- Hispanics

Entropy in Image Analysis

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ISBN: 9783039210923 9783039210930 Year: Pages: 456 DOI: 10.3390/books978-3-03921-093-0 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2019-06-26 08:44:06
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Image analysis is a fundamental task for extracting information from images acquired across a range of different devices. Since reliable quantitative results are requested, image analysis requires highly sophisticated numerical and analytical methods—particularly for applications in medicine, security, and remote sensing, where the results of the processing may consist of vitally important data. The contributions to this book provide a good overview of the most important demands and solutions concerning this research area. In particular, the reader will find image analysis applied for feature extraction, encryption and decryption of data, color segmentation, and in the support new technologies. In all the contributions, entropy plays a pivotal role.

Keywords

image retrieval --- multi-feature fusion --- entropy --- relevance feedback --- chaotic system --- image encryption --- permutation-diffusion --- SHA-256 hash value --- dynamic index --- entropy --- keyframes --- Shannon’s entropy --- sign languages --- video summarization --- video skimming --- image encryption --- multiple-image encryption --- two-dimensional chaotic economic map --- security analysis --- image encryption --- chaotic cryptography --- cryptanalysis --- chosen-plaintext attack --- image information entropy --- blind image quality assessment (BIQA) --- information entropy, natural scene statistics (NSS) --- Weibull statistics --- discrete cosine transform (DCT) --- ultrasound --- hepatic steatosis --- Shannon entropy --- fatty liver --- metabolic syndrome --- multi-exposure image fusion --- texture information entropy --- adaptive selection --- patch structure decomposition --- image encryption --- time-delay --- random insertion --- information entropy --- chaotic map --- uncertainty assessment --- deep neural network --- random forest --- Shannon entropy --- positron emission tomography --- reconstruction --- field of experts --- additive manufacturing --- 3D prints --- 3D scanning --- image entropy --- depth maps --- surface quality assessment --- machine vision --- image analysis --- Arimoto entropy --- free-form deformations --- normalized divergence measure --- gradient distributions --- nonextensive entropy --- non-rigid registration --- pavement --- macrotexture --- 3-D digital imaging --- entropy --- decay trend --- discrete entropy --- infrared images --- low contrast --- multiscale top-hat transform --- image encryption --- DNA encoding --- chaotic cryptography --- cryptanalysis --- image privacy --- computer aided diagnostics --- colonoscopy --- Rényi entropies --- structural entropy --- spatial filling factor --- binary image --- Cantor set --- Hénon map --- Minkowski island --- prime-indexed primes --- Ramanujan primes --- Kapur’s entropy --- color image segmentation --- whale optimization algorithm --- differential evolution --- hybrid algorithm --- Otsu method --- image encryption --- dynamic filtering --- DNA computing --- 3D Latin cube --- permutation --- diffusion --- fuzzy entropy --- electromagnetic field optimization --- chaotic strategy --- color image segmentation --- multilevel thresholding --- contrast enhancement --- sigmoid --- Tsallis statistics --- q-exponential --- q-sigmoid --- q-Gaussian --- ultra-sound images --- person re-identification --- image analysis --- hash layer --- quantization loss --- Hamming distance --- cross-entropy loss --- image entropy --- Shannon entropy --- generalized entropies --- image processing --- image segmentation --- medical imaging --- remote sensing --- security

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