The Role of Anti- and Pro-apoptotic Cofactors in Hypoxia/Reoxygenation-Dependent Regulation of MAPKs in the Brain of an Anoxia-Tolerant Model

The cellular and molecular regulation of MAPKs and apoptosis was investigated in a model of hypoxiatolerance. Survival of neurons in Chrysemys picta bellii, an anoxia-tolerant turtle, involves a reduction in energy metabolism. The biochemical/physiological mechanisms of anoxia tolerance have been examined at the level of ion transport and ATP turnover. However, changes in the phosphorylation state of key enzymes and kinases, mainly, MAPKs, may occur during anoxia, thereby reversible protein phosphorylation could be a critical factor and major mechanism of metabolic reorganization for enduring anaerobiosis. If a turtle were to undergo hypoxia akin to that experienced in its native habitat, it was placed in a glass aquarium filled with water to within a half inch of the top. After the turtle was anesthetized, through extended hypoxia or anesthesia, the animal was sacrificed by decapitation. The brain was then excised and placed in anoxic artificial cerebrospinal fluid. Total protein extraction was performed by homogenizing brain in a buffer, followed by threonine and tyrosine phosphorylation determination of MAPKs, and caspase activity. MAPKp38 was decreased after reoxygenation following 1 day and 1 week hypoxia. The effect of hypoxia on the phosphorylation of MAPKERK was biphasic: Enhancement at 5h and inhibition at 6 weeks. Pro-caspases 8/9 were unchanged by hypoxia until increasing at 6 weeks. Both pro-caspases were upregulated by reoxygenation at 1 day or 6 weeks hypoxia. Neither hypoxia nor reoxygenation induced the cleavage of pro-caspases 8/9 into p20 and p10, respectively. Furthermore, hypoxia induced Bax at 3 days and 1 week, and reoxygenation increased Bax - 4-fold at 1 day. Although the expression of Bcl-2 was slightly increased by hypoxia, [Bcl-2] was 3-4-fold smaller in comparison with Bax. These results indicate that hypoxia up-regulates MAPKERK but not MAPKp38; hypoxia/reperfusion increases the expression of caspases and pro-apoptotic cofactors. The patterns of MAPK regulation suggest the significance of these kinases in cellular adaptation to oxygen deprivation with biomedical correlations, and thereby identify novel natural responsive signaling cofactors in Chrysemys picta bellii with potential pharmacologic and clinical applications

Molecular Regulation of Inflammatory Pain and Hyperalgesia - Is NF-?B the Lynchpin?

Inflammatory cells and inflammatory mediators are crucially involved in the genesis, persistence and severity of pain following trauma, infection or nerve injury. The mechanisms and pathways mediating pain and nociception are transcriptionally regulated. The transcriptional mediator nuclear factor (NF)-kB plays a major role in regulating the inflammatory milieu, ostensibly via the control of gene expression/suppression. An association has recently emerged to establish a possible link between NF-kB and pain/nociception, purportedly through the regulation of the inflammatory loop and the secretion (biosynthesis) of pro-inflammatory mediators. Current concepts conspicuously indicate that the effective inhibition of this transcription factor and associated upstream kinase(s) and the pathways that regulate its nuclear translocation could be major targets in a new strategy for the alleviation of inflammation and inflammatory-related pain. To better understand this relationship between NF-kB and the evolution of pain and hyperalgesia/nociception, it is imperative to unravel the molecular basis of this process. This survey definitively integrates current themes pertaining to the pivotal role that NF-kB shares in regulating pain through the decoding of implicated molecular pathways and signaling mechanisms

The Emphatic Role of Mitogen-Activated Protein Kinases (MAPKs) in the Cellular Mechanisms Mediating Alzheimer's Disease

Alzheimer's disease (AD) is a neurogenetic condition that affects the processes via which the brain functions. Major observable hallmarks of AD are accumulated clusters of proteins in the brain. These clusters, termed neurofibrillary tangles (NFT), resemble pairs of threads wound around each other in a helix fashion accumulating within neurons. These tangles consist of a protein called Tau, which binds to tubulin, thus forming microtubules. Unlike NFTs, deposits of amyloid precursor protein (ß-APP) gather in the spaces between nerve cells. The nearby neurons often look swollen and deformed, and the clusters of protein are usually accompanied by reactive inflammatory cells, microglia, which are part of the brain's immune system responsible for degrading and removing damaged neurons or plaques. Since phosphorylation/dephosphorylation mechanisms are crucial in the regulation of Tau and ß-APP, a superfamily of mitogen-activated protein kinases (MAPKs) has recently emerged as key regulators of the formation of plagues, eventually leading to dementia and AD. The complex molecular interactions between MAPKs and proteins (plagues) associated with the evolution of AD form a cornerstone in the knowledge of a still burgeoning field of neurodegenerative diseases and ageing. This review overviews current understanding of the molecular pathways related to MAPKs and their role in the development of AD and, possibly, dementia. MAPKs, therefore, may constitute a neurogenetic, therapeutic target for the diagnosis and evolution of a preventative medical strategy for early detection, and likely treatment, of Alzheimer's

Redox Regulation of Pro-Inflammatory Cytokines and IκB-α/NF-κB Nuclear Translocation and Activation

Abstract Reduction-oxidation (redox) state constitutes such a potential signaling mechanism for the regulation of an inflammatory signal associated with oxidative stress. Exposure of alveolar epithelial cells to ascending DpO 2 regimen AE reactive oxygen species (ROS)-generating systems induced a dose-dependent release of interleukin (IL)-1b, IL-6, and tumor necrosis factor (TNF)-a. Similarly, the Escherichia coli-derived lipopolysaccharide-endotoxin (LPS) up-regulated cytokine biosynthesis in a dose-and time-dependent manner. Irreversible inhibition of c-glutamylcysteine synthetase, the rate-limiting enzyme in the biosynthesis of glutathione (GSH), by L -buthionine-(S,R)-sulfoximine (BSO), induced the accumulation of ROS and augmented DpO 2 and LPS-mediated release of cytokines. Analysis of the molecular mechanism implicated revealed an inhibitory-jB (IjB-a)/nuclear factor-jB (NF-jB)-independent pathway in mediating redox-dependent regulation of inflammatory cytokines. BSO stabilized cytosolic IjB-a and downregulated its phosphorylation, thereby blockading NF-jB activation, yet it augmented cytokine secretion. Glutathione depletion is associated with the augmentation of oxidative stress-mediated inflammatory state in a ROS-dependent mechanism and the IjB-a/ NF-jB pathway is redox-sensitive but differentially involved in regulating redox-dependent regulation of cytokines. Ó 2002 Elsevier Science (USA). All rights reserved. Keywords: Antioxidant; Chemioxyexcitation; Cytokines; Glutathione disequilibrium; Pharmacotherapy; Reactive oxygen species; Redox/thiol regulation Signaling pathways linked to the generation of reactive oxygen species (ROS) are believed to constitute a vital component of cellular oxygen signaling mechanisms which integrate the expression of genes involved in energy production, oxygen transfer, cellular differentiation, and free radical scavengin

Oxygen sensing and oxidant/redox-related pathways

Abstract What is the nature of the oxygen sensor(s) and how do organisms sense variations in oxygen? A progressive rise of oxidative stress due to the altered reduction-oxidation (redox) homeostasis appears to be one of the hallmarks of the processes that regulate gene transcription. Dynamic changes in oxygen homeostasis and its close association with redox equilibrium, therefore, constitute a signaling mechanism for the expression/activation of oxygenes. This variation subsequently regulates the compartmentalization and functioning of HIF-1a and NF-jB. In addition, oxygen-evoked regulation of HIF-1a and NF-jB is closely coupled with intracellular redox state, such that modulating redox equilibrium affects their responsiveness at the molecular level (expression/transactivation). Interestingly, are these particular transcription factors potential oxygen sensors? The basic components of the intracellular oxidative/redox machinery and its crucial regulation of oxygen-and redox-sensitive transcription factors may help understand the network of oxygen sensing mechanisms and redox-related pathways. Ó 2004 Published by Elsevier Inc. Keywords: Glutathione; HIF-1a; Hyperoxia; Hypoxia; NF-jB; Oxygen sensing; Transcription factor; Redox equilibrium The major question of how cells sense oxygen (and respond to it) has physiological and pathophysiological implication

Predictors of locating children participants in epidemiological studies 20 years after last contact: Internet resources and longitudinal research

This study examines predictors of locating participants that were last contacted 20 years ago using public web-search directories, in order to facilitate longitudinal environmental health research. Participants (n = 3,202) resided in four distinct geographical neighborhoods in Hamilton, Ontario during childhood; they were between 15 and 17 years old when they were last contacted in 1986. Data used for tracing included available addresses, telephone numbers, given names, and parental names. Reverse and forward search strategies were used to retrieve updated contact details. 43% of the sample was traced using online directories. Following ethical approval, participants were contacted using traced data and 29% of the original cohort was located. Predictors of locating participants were: availability of paternal names, being traced to original addresses or telephone numbers, gender (male), relatively higher socioeconomic status in childhood, and not being exposed to smoking in childhood. Where participants resided in childhood was not a significant predictor of locating participants. Although 13% of the sample was traced using forward search by name, only 4% were located. For participants traced to available addresses or telephone numbers, the difference between the proportions of traced and located participants was \u3c3%. Prospective studies on children may benefit from including the listed names that pertain to each child\u27s telephone number and full parental names at recruitment, thereby increasing the likelihood of locating participants using Internet resources. Integrating the use of Internet-based public directories for cohort reconstruction can reduce financial costs related to follow-up for longitudinal research. © 2009 Springer Science+Business Media B.V

A case study with breast cancer and brain metastasis encompassing acute onset of amnesia and altered mental status due to limbic encephalitis - biochemical and proteomic aspects

A biochemical case study is reported on a 50-year old lady known to have breast cancer. The woman was treated by mastectomy and this was followed by unraveling brain metastases three years post-diagnosis of the cancer, which was treated by radiation and chemotherapy. Two months after ending her treatment, she exhibited acute changes in her mental status manifested by severe amnesia and fever. A generalized analytical and biochemical assessment revealed the presence of paraneoplastic limbic encephalitis

Asymmetry and structural system analysis of the proximal femur meta-epiphysis: osteoarticular anatomical pathology

<p>Abstract</p> <p>Background</p> <p>The human femur is commonly considered as a subsystem of the locomotor apparatus with four conspicuous levels of organization. This phenomenon is the result of the evolution of the locomotor apparatus, which encompasses both constitutional and individual variability. The work therein reported, therefore, underlies the significance of observing anatomical system analysis of the proximal femur meta-epiphysis in normal conditions, according to the anatomic positioning with respect to the right or left side of the body, and the presence of system asymmetry in the meta-epiphysis structure, thus indicating structural and functional asymmetry.</p> <p>Methods</p> <p>A total of 160 femur bones of both sexes were compiled and a morphological study of 15 linear and angulated parameters of proximal femur epiphysis was produced, thus defining the linear/angulated size of tubular bones. The parameters were divided into linear and angulated groups, while maintaining the motion of the hip joint and transmission of stress to the unwanted parts of the limb. Furthermore, the straight and vertical diameters of the femoral head and the length of the femoral neck were also studied. The angle between the neck and diaphysis, the neck antiversion and angle of rotation of the femoral neck were subsequently measured. Finally, the condylo-diaphyseal angle with respect to the axis of extremity was determined. To visualize the force of intersystem ties, we have used the method of correlation galaxy construction.</p> <p>Results</p> <p>The absolute numeral values of each linear parameter were transformed to relative values. The values of superfluity coefficient for each parameter in the right and left femoral bone groups were estimated and Pearson's correlation coefficient has been calculated (> 0.60). Retrospectively, the observed results have confirmed the presence of functional asymmetry in the proximal femur meta-epiphysis. On the basis of compliance or insignificant difference in the confidence interval of the linear parameters, we have revealed, therefore, a discrepancy in values between the neck and the diaphysis angle and the angle of femoral neck rotation (range displacement of confident interval to a greater degree to the right).</p> <p>Conclusion</p> <p>This study assessed the observations of a systemic anatomical study encompassing the proximal femur meta-epiphysis behavior in normal condition. This work has significance in medical practice as the theoretical basis is also required in knowing the decreased frequency and degree of severity of osteoarthritic pathologies in the dominant lower extremity.</p