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New Approaches to the Pathogenesis of Sudden Intrauterine Unexplained Death and Sudden Infant Death Syndrome

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889453016 Year: Pages: 104 DOI: 10.3389/978-2-88945-301-6 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Neurology
Added to DOAB on : 2018-02-27 16:16:45
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Sudden Infant Death Syndrome (SIDS) is the leading cause of death among infants in the first year of age. The more known definition of SIDS is the sudden unexpected death of an infant less than 1 year of age, with onset of the fatal episode apparently occurring during sleep, that remains unexplained after a thorough investigation, including performance of a complete autopsy and review of the circumstances of death and the clinical history. Despite the success of the “Back to Sleep” campaigns to reduce the risks introduced worldwide, the frequency of SIDS (striking one infant every 750-1,000 live births) has not significantly declined in the last years. Sudden Intrauterine Unexplained Death Syndrome (SIUDS), referring to fetuses that die unexpectedly, particularly in the last weeks of gestation, without any cause even after a complete autopsy, including examination of the placental disk, umbilical cord and fetal membranes, has a six-eightfold greater incidence than that of SIDS. Even if the pathogenetic mechanism of these deaths has not yet been determined, the neuropathology seems to be a consistent substrate in both SIUDS and SIDS. Subtle common developmental abnormalities of brainstem nuclei checking the vital functions have been highlighted, frequently related to environmental risk factors, such as cigarette smoke, air and water pollution, pesticides, food contamination, etc. Exogenous toxic factors can in fact interact in complex ways with the genetic constitution of the infant leading to polymorphisms and/or mutations of specific genes (as polymorphisms of the serotonin transporter gene 5-HTT, the regulator of the synaptic serotonin concentration, and of the PHOX2B, the key gene in the Congenital Central Hypoventilation Syndrome). These interactions can directly injure the development of the autonomic nervous system, frequently resulting in hypoplasia of the vital brainstem centers, and consequently in sudden death. It is very important to continue studying these syndromes and in particular identify all possible congenital alterations and their correlation with the exposure to environmental risk factors, in order to reduce their incidence and mitigate the surrounding social concern. The goal of this research topic is to propose new approaches to explain the pathogenesis of both SIUDS and SIDS and consequently new prevention strategies to decrease the incidence of these unexpected and very devastating events for families. Expert authors in the Topic field are encouraged to submit original research articles aimed to widen the current knowledge on the pathological substrates of these deaths, also considering the correlations with possible risk factors. Submissions of hypotheses, opinions and commentaries are also welcome. This Research Topic would lead to development of targeted risk-lowering strategies to reduce the incidence of both SIUDS and SIDS. Furthermore, the adoption of appropriate preventive measures could also lead to improve the quality of life in adults, promoting active and healthy aging.

Sudden Death in Epilepsy: Basic and Translational Research

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889455942 Year: Pages: 71 DOI: 10.3389/978-2-88945-594-2 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Neurology
Added to DOAB on : 2019-01-23 14:53:43
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Sudden Death in Epilepsy (SUDEP) is a major cause of death in people with epilepsy, accounting for up to 17% of all deaths. Research interest is exploding, focusing on epidemiology, basic mechanisms, identification of risk factors, and biomarkers. New wearable technologies are approved or in development. These incorporate accelerometers and advanced heart rate detection, which are linked to smart phones. The advent of FDA approved detection devices now allows immediate intervention by family and loved ones. The next frontier for SUDEP remains effective prevention strategies, which will likely include new devices and pharmacologic interventions. This volume is organized into three sections: Basic and Physiologic Mechanisms; Clinical Risk Factors and Inventories; and Very Early Research into Pharmacologic Interventions. It is our hope that this eBook will inform clinicians of key advances in the field, and to foster and stimulate basic and translational research with one purpose: To prevent SUDEP in those at risk.

Infection and Inflammation: Potential Triggers of Sudden Infant Deaths

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450497 Year: Pages: 94 DOI: 10.3389/978-2-88945-049-7 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2018-02-27 16:16:44
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There is a growing body of evidence that infectious agents or their products contribute to events leading to unexpected infant deaths. This issue summarizes the current information on the interactions between genetic background of the infant, environmental and developmental risk factors, and the microbial flora of the infant that could trigger lethal responses to common infections.

Non-Ordinary Mental Expressions

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889194858 Year: Pages: 135 DOI: 10.3389/978-2-88919-485-8 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2015-11-16 15:44:59
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So-called altered states of consciousness (ASC) are an intriguing, still under-researched topic, with profound neuropsychological and epistemological implications. In the last few decades there has been increasing multidisciplinary interest in consciousness and ASC, a term encompassing a wide range of pathological and non-pathological conditions, including dreaming, near-death experiences (NDEs), hypnagogic states, hallucinogenic experiences, epileptic seizures, psychotic symptoms, coma, and minimally conscious states. There has also been considerable research on procedures that may affect ASC including hypnosis and various forms of meditation. Since the term altered implies for some abnormality or dysfunction, the concept of anomalous experiences (not necessarily implying pathology) is increasingly used and more general.The term non-ordinary mental expressions (NOME) encompasses both anomalous (at least for a particular culture at a particular time) experiences and related neuropsychological processes and induction procedures. Our use of non-ordinary: a) does not assume pathology; and b) is suitable for sophisticated and positive mental activities, including, creativity, intuition, and some forms of spirituality. We use the term mind to include both conscious and preconscious processes, and question the notion that, "ordinary", waking consciousness provides the only epistemologically valid stance with regard to the mind and its interactions with reality. Similarly, although genius and madness both imply something beyond normal, they differ importantly in their ontology and implications. In short, NOME refers to both experiences and procedures that seek to change short- or long-term psychological processes. Regarding the latter, meditation is an intentional activity, calling for training of attention and reflective awareness, and varying in specific procedures and outcomes. With regard to an absence of pathology, NDEs, which have several features in common with mystical experiences, may occur in the absence of any brain disorder and bring about positive changes. Reductionist interpretations of NDEs as pathophysiological do not explain nor encompass the whole range of their phenomenology. Instead, brain areas and neurotransmitters potentially involved in these experiences may provide a common terrain for both pathological and non-pathological mind expressions.We believe that a proper approach to NOME should adopt a neurophenomenological approach to the study of brain mechanisms and subjective experiences as a whole, integrating experiential and neuroscientific perspectives, without any a priori fixed hierarchy or ontology. The brain-mind relationship can be analyzed as a recursive loop, where brain activity gives rise to mental phenomena and mental processes, in turn, yield functional and plastic changes in the brain. This Research Topic will include international experts in NOME as well as young researchers within a multidisciplinary discussion, in which neuroscientists, psychologists, psychiatrists, philosophers, anthropologists, and other professionals will be asked to contribute. We aim to reappraise the importance of NOME and its implications for the mind-brain-world relationship. The editors will solicit original research contributions as well as theoretical papers, such as reviews, mini-reviews, and theoretical discussions.

Mitochondria: the cell powerhouse and nexus of stress

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889192830 Year: Pages: 121 DOI: 10.3389/978-2-88919-283-0 Language: English
Publisher: Frontiers Media SA
Subject: Biology --- Physiology --- Science (General)
Added to DOAB on : 2015-12-10 11:59:06
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Mitochondrion, a sub-cellular organelle originated from primary endosymbiosis, plays a vital role in energy metabolism of eukaryotic cells. The transfer of electrons through the electron transport chain (ETC) to molecular oxygen accompanied by the extrusion of protons from the matrix generate an electrochemical gradient across the inner mitochondrial membrane (IMM) that is used for ATP synthesis by oxidative phosphorylation. Despite many aspects of ATP synthesis have been delineated, regulatory mechanisms responsible for energy synthesis and transfer still remain to be uncovered. In addition to energy function, mitochondria play a crucial role in cell metabolism under both physiological and pathological conditions through their participation in many intracellular signaling pathways. Studies over the last 30 years provide strong evidence that mitochondria are the nexus of various stresses which initiate cell death through apoptosis, oncosis, necrosis and autophagy depending on the severity of the stress and cellular energy status. The release of several pro-apoptotic proteins such as cytochrome c, Smac/DIABLO, AIF, endonuclease G from intermembrane space initiates both caspase-dependent and caspase-independent apoptosis. The formation of the mitochondrial permeability transition pore in the IMM promotes cell death mostly through necrosis whereas a mild stress activates autophagy. Due to their critical roles in both cell death and survival mitochondria have been widely considered as an important target for various pharmacological and conditional therapeutic approaches. Currently, a large number of mitochondria-targeted agents are suggested to prevent (in ischemia reperfusion injury, cardiovascular, neurodegenerative and other diseases) or stimulate (in various cancers) cell death. This Research Topic focuses on the role of mitochondria in the regulation of cell metabolism and signaling under physiological and pathological conditions. Studies performed on cultured cells and isolated organs/tissues using different animal and cellular models of various diseases are also included and discussed.

Maintenance of Genome Integrity: DNA Damage Sensing, Signaling, Repair and Replication in Plants

Authors: --- --- --- --- et al.
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889198207 Year: Pages: 129 DOI: 10.3389/978-2-88919-820-7 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2016-01-19 14:05:46
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Environmental stresses and metabolic by-products can severely affect the integrity of genetic information by inducing DNA damage and impairing genome stability. As a consequence, plant growth and productivity are irreversibly compromised. To overcome genotoxic injury, plants have evolved complex strategies relying on a highly efficient repair machinery that responds to sophisticated damage perception/signaling networks. The DNA damage signaling network contains several key components: DNA damage sensors, signal transducers, mediators, and effectors. Most of these components are common to other eukaryotes but some features are unique to the plant kingdom. ATM and ATR are well-conserved members of PIKK family, which amplify and transduce signals to downstream effectors. ATM primarily responds to DNA double strand breaks while ATR responds to various forms of DNA damage. The signals from the activated transducer kinases are transmitted to the downstream cell-cycle regulators, such as CHK1, CHK2, and p53 in many eukaryotes. However, plants have no homologue of CHK1, CHK2 nor p53. The finding of Arabidopsis transcription factor SOG1 that seems functionally but not structurally similar to p53 suggests that plants have developed unique cell cycle regulation mechanism. The double strand break repair, recombination repair, postreplication repair, and lesion bypass, have been investigated in several plants. The DNA double strand break, a most critical damage for organisms are repaired non-homologous end joining (NHEJ) or homologous recombination (HR) pathway. Damage on template DNA makes replication stall, which is processed by translesion synthesis (TLS) or error-free postreplication repair (PPR) pathway. Deletion of the error-prone TLS polymerase reduces mutation frequencies, suggesting PPR maintains the stalled replication fork when TLS is not available. Unveiling the regulation networks among these multiple pathways would be the next challenge to be completed. Some intriguing issues have been disclosed such as the cross-talk between DNA repair, senescence and pathogen response and the involvement of non-coding RNAs in global genome stability. Several studies have highlighted the essential contribution of chromatin remodeling in DNA repair. DNA damage sensing, signaling and repair have been investigated in relation to environmental stresses, seed quality issues, mutation breeding in both model and crop plants and all these studies strengthen the idea that components of the plant response to genotoxic stress might represent tools to improve stress tolerance and field performance. This focus issue gives researchers the opportunity to gather and interact by providing Mini-Reviews, Commentaries, Opinions, Original Research and Method articles which describe the most recent advances and future perspectives in the field of DNA damage sensing, signaling and repair in plants. A comprehensive overview of the current progresses dealing with the genotoxic stress response in plants will be provided looking at cellular and molecular level with multidisciplinary approaches. This will hopefully bring together valuable information for both plant biotechnologists and breeders.

Sensory Hair Cell Death and Regeneration

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450008 Year: Pages: 266 DOI: 10.3389/978-2-88945-000-8 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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Sensory hair cells are the specialized mechanosensory receptors found in vertebrate auditory, vestibular, and lateral line organs that transduce vibratory and acoustic stimuli into the sensations of hearing and balance. Hair cells can be damaged due to such factors as aging, ototoxic chemicals, acoustic trauma, infection, or genetic factors. Loss of these hair cells lead to deficits in hearing and balance, and in mammals, such deficits are permanent. In contrast, non-mammalian vertebrates exhibit the capability to regenerate missing hair cells. Researchers have been examining the process of hair cell death and regeneration in animal models in an attempt to find ways of either preventing hair cell loss or stimulating the production of new hair cells in mammals, with the ultimate goal of finding new therapeutics for human sensorineural hearing and balance deficits. This has led to a wide array of research on sensory hair cells- such as understanding the factors that cause hair cell loss and finding agents that protect them from damage, elucidating the cell signaling pathways activated during hair cell death, examining the genes and cellular pathways that are regulated during the process of hair cell death and regeneration, and characterizing the functional sensory loss and recovery following acoustic or ototoxic insults to the inner ear. This research has involved cell and developmental biologists, physiologists, geneticists, bioinformaticians, and otolaryngologists. In this Research Topic, we have collated reviews of the past progress of hair cell death and regeneration studies and original research articles advancing sensory hair cell death and regeneration research into the future.

Reelin-Related Neurological Disorders and Animal Models

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889451111 Year: Pages: 179 DOI: 10.3389/978-2-88945-111-1 Language: English
Publisher: Frontiers Media SA
Subject: Neurology --- Science (General)
Added to DOAB on : 2017-07-06 13:27:36
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The Reeler mutation was so named because of the alterations in gait that characterize homozygous mice. Several decades after the description of the Reeler phenotype, the mutated protein was discovered and named Reelin (Reln). Reln controls a number of fundamental steps in embryonic and postnatal brain development. A prominent embryonic function is the control of radial neuronal migration. As a consequence, homozygous Reeler mutants show disrupted cell layering in cortical brain structures. Reln also promotes postnatal neuronal maturation. Heterozygous mutants exhibit defects in dendrite extension and synapse formation, correlating with behavioral and cognitive deficits that are detectable at adult ages. The Reln-encoding gene is highly conserved between mice and humans. In humans, homozygous RELN mutations cause lissencephaly with cerebellar hypoplasia, a severe neuronal migration disorder that is reminiscent of the Reeler phenotype. In addition, RELN deficiency or dysfunction is also correlated with psychiatric and cognitive disorders, such as schizophrenia, bipolar disorder and autism, as well as some forms of epilepsy and Alzheimer's disease. Despite the wealth of anatomical studies of the Reeler mouse brain, and the molecular dissection of Reln signaling mechanisms, the consequences of Reln deficiency on the development and function of the human brain are not yet completely understood. This Research Topic include reviews that summarize our current knowledge of the molecular aspects of Reln function, original articles that advance our understanding of its expression and function in different brain regions, and reviews that critically assess the potential role of Reln in human psychiatric and cognitive disorders.

Current Challenges in Cardiovascular Molecular Diagnostics

Authors: --- --- --- --- et al.
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889452811 Year: Pages: 128 DOI: 10.3389/978-2-88945-281-1 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General)
Added to DOAB on : 2018-02-27 16:16:44
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The field of cardiovascular genetics has tremendously benefited from the recent application of massive parallel sequencing technology also referred to as next generation sequencing (NGS). However, along with the discovery of additional genes associated with human cardiac diseases, the analysis of large dataset of genetic information uncovered a much more complex and variegated landscape, which often departs from the comfort zone of the monogenic Mendelian diseases image that clinical molecular geneticists have been well acquainted with for many decades. It is now clear that, in addition to highly penetrant genetic variants, which in isolation are able to recapitulate the full clinical presentation when expressed in animal models, we are now aware that a small but significant fraction of subjects presenting with cardiac muscle diseases such as cardiomyopathies or primary arrhythmias such as long QT syndrome (LQTS), may harbor at least two deleterious variants in the same gene (compound heterozygous) or in different gene (double heterozygous). Although the clinical presentation in subjects with more than one deleterious variant appears to be more severe and with an earlier disease onset, it somehow changes the viewpoint of clinical molecular geneticists whose aim is to identify all possible genetic contributors to a human condition. In this light, the employment in clinical diagnostics of the NGS technology, allowing the simultaneous interrogation of a DNA target spanning from large panel of genes up to the entire genome, will definitely aid at uncovering all such contributors, which will have to be tested functionally to confirm their role in human cardiac conditions. The uncovering of all clinically relevant deleterious changes associated with a cardiovascular disease would probably increase our understanding of the clinical variability commonly occurring among affected family relatives, and potentially provide with unexpected therapeutic targets for the treatment of symptoms related to the presence of “accessory” deleterious genetic variants other than the key molecular culprit. The objective of this Research Topic is to explore the current challenges presenting to the cardiovascular genetics providers, such as clinical geneticists, genetic counselors, clinical molecular geneticists and molecular pathologists involved in the diagnosis, counseling, testing and interpretation of genetic tests results for the comprehensive management of patients affected by cardiovascular genetic disorders.

NETosis 2: The Excitement Continues

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889453795 Year: Pages: 362 DOI: 10.3389/978-2-88945-379-5 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2018-11-16 17:17:57
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NETosis, a form of cell death that manifests by the release of decondensed chromatin to the extracellular space, provides valuable insights into mechanisms and consequences of cellular demise. Because extracellular chromatin can immobilize microbes, the extended nucleohistone network was called a neutrophil extracellular trap (NET), and the process of chromatin release was proposed to serve an innate immune defense function. Extracellular chromatin NETs were initially observed in studies of neutrophils and are most prominent in these types of granulocytes. Subsequent studies showed that other granulocytes and, in a limited way, other cells of the innate immune response may also release nuclear chromatin following certain kinds of stimulation. Variations of NETosis were noted with cells that remain temporarily motile after the release of chromatin. Numerous stimuli for NETosis were discovered, including bacterial breakdown products, inflammatory stimuli, particulate matter, certain crystals, immune complexes and activated thrombocytes. Fundamental explorations into the mechanisms of NETosis observed that neutrophil enzyme activity (PAD4, neutrophil elastase, proteinase 3 and myeloperoxidase) and signal transduction pathways contribute to the regulation of NETosis. Histones in NET chromatin become modified by peptidylarginine deiminase 4 (PAD4) and cleaved at specific sites by proteases, leading to extensive chromatin externalization. In addition, NETs serve for attachment of bactericidal enzymes including myeloperoxidase, leukocyte proteases, and the cathelicidin LL-37. NETs are decorated with proteases and may thus contribute to tissue destruction. However, the attachment of these enzymes to NET-associated supramolecular structures restricts systemic spread of the proteolytic activity. While the benefit of NETs in an infection appears obvious, NETs also participate as key protagonists in various pathologic states. Therefore, it is essential for NETs to be efficiently cleared; otherwise digestive enzymes may gain access to tissues where inflammation takes place. Persistent NET exposure at sites of inflammation may lead to a further complication: NET antigens may provoke acquired immune responses and, over time, could initiate autoimmune reactions, serve as antigen for nuclear autoantibodies and foster DNA immune complex-related inflammation. Neutrophil products and deiminated proteins comprise an important group of autoantigens in musculoskeletal disorders. Aberrant NET synthesis and/or clearance are often associated with inflammatory and autoimmune conditions. Recent evidence also implicates aberrant NET formation in the development of endothelial damage, atherosclerosis and thrombosis. Intravital microscopy provides evidence for conditions that induce NETosis in vivo. Furthermore, NETs can easily be detected in synovial fluid and tissue sections of patients with arthritis and gout. NETosis is thus of interest to researchers who investigate innate immune responses, host-pathogen interactions, chronic inflammatory disorders, cell and vascular biology, biochemistry, and autoimmunity. As we enter the second decade of research on NETosis, it is useful and timely to review the mechanisms and pathways of NET formation, their role in bacterial and fungal defense and their importance as inducers of autoimmune responses.

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