scholarly journals Role of channels in the oxygen permeability of red blood cells

2020 ◽  
Author(s):  
Pan Zhao ◽  
R. Ryan Geyer ◽  
Ahlam I. Salameh ◽  
Amanda B. Wass ◽  
Sara Taki ◽  
...  
Keyword(s):  
Paradigm Shift ◽  
Oxygen Permeability ◽  
Membrane Lipids ◽  
Pharmacological Intervention ◽  
Double Knockout ◽  
Physiological Regulation ◽  
Mathematical Simulations ◽  
Protein Channels ◽  
Rule Out

AbstractMany have believed that oxygen (O2) crosses red blood cell (RBC) membranes by dissolving in lipids that offer no resistance to diffusion. However, using stopped-flow (SF) analyses of hemoglobin (Hb) absorbance spectra during O2 off-loading from mouse RBCs, we now report that most O2 traverses membrane-protein channels. Two agents excluded from the RBC interior markedly slow O2 off-loading: p-chloromercuribenzenesulfonate (pCMBS) reduces inferred membrane O2 permeability (PMembrane) by ∼82%, and 4,4’-diisothiocyanatostilbene-2,2’-disulfonate (DIDS), by ∼56%. Because neither likely produces these effects via membrane lipids, we examined RBCs from mice genetically deficient in aquaporin-1 (AQP1), the Rh complex (i.e., rhesus proteins RhAG + mRh), or both. The double knockout (dKO) reduces PMembrane by ∼55%, and pCMBS+dKO, by ∼91%. Proteomic analyses of RBC membranes, flow cytometry, hematology, and mathematical simulations rule out explanations involving other membrane proteins, RBC geometry, or extracellular unconvected fluid (EUF). By identifying the first two O2 channels and pointing to the existence of other O2 channel(s), all of which could be subject to physiological regulation and pharmacological intervention, our work represents a paradigm shift for O2 handling.

Posttransplant CMV infection and the role of immunosuppression (Sponsor: Novartis Pharma GmbH, Nürnberg)

2016 ◽  
Vol 04 (01) ◽  
pp. 4-10
Keyword(s):  
Lower Incidence ◽  
Paradigm Shift ◽  
Mtor Inhibitor ◽  
De Novo ◽  
Expert Panel ◽  
Risk Of Infection ◽  
Cmv Infection ◽  
Expert Meeting ◽  
Selection Of

AbstractImmunosuppression permits graft survival after transplantation and consequently a longer and better life. On the other hand, it increases the risk of infection, for instance with cytomegalovirus (CMV). However, the various available immunosuppressive therapies differ in this regard. One of the first clinical trials using de novo everolimus after kidney transplantation [1] already revealed a considerably lower incidence of CMV infection in the everolimus arms than in the mycophenolate mofetil (MMF) arm. This result was repeatedly confirmed in later studies [2–4]. Everolimus is now considered a substance with antiviral properties. This article is based on the expert meeting “Posttransplant CMV infection and the role of immunosuppression”. The expert panel called for a paradigm shift: In a CMV prevention strategy the targeted selection of the immunosuppressive therapy is also a key element. For patients with elevated risk of CMV, mTOR inhibitor-based immunosuppression is advantageous as it is associated with a significantly lower incidence of CMV events.

E-Projects Challenges in India – Role of Human Resource Management and Technology

2018 ◽  
Vol 6 (8) ◽  
pp. 263
Author(s):  
Ramnik Kaur
Keyword(s):  
Developing Countries ◽  
Public Administration ◽  
Paradigm Shift ◽  
Successful Implementation ◽  
The Public ◽  
Government Services ◽  
The Past ◽  
The Government ◽  
Traditional Approaches

E-governance is a paradigm shift over the traditional approaches in Public Administration which means rendering of government services and information to the public by using electronic means. In the past decades, service quality and responsiveness of the government towards the citizens were least important but with the approach of E-Government the government activities are now well dealt. This paper withdraws experiences from various studies from different countries and projects facing similar challenges which need to be consigned for the successful implementation of e-governance projects. Developing countries like India face poverty and illiteracy as a major obstacle in any form of development which makes it difficult for its government to provide e-services to its people conveniently and fast. It also suggests few suggestions to cope up with the challenges faced while implementing e-projects in India.

The Role of Lipids and Membranes in the Pathogenesis of Alzheimer's Disease: A Comprehensive View

2018 ◽  
Vol 15 (13) ◽  
pp. 1191-1212 ◽  
Author(s):  
Botond Penke ◽  
Gábor Paragi ◽  
János Gera ◽  
Róbert Berkecz ◽  
Zsolt Kovács ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Signaling Pathways ◽  
Membrane Lipids ◽  
Specific Protein ◽  
Dietary Factors ◽  
Lipid Signaling ◽  
Special Role ◽  
Aβ Peptides

Lipids participate in Amyloid Precursor Protein (APP) trafficking and processing - important factors in the initiation of Alzheimer’s disease (AD) pathogenesis and influence the formation of neurotoxic β-amyloid (Aβ) peptides. An important risk factor, the presence of ApoE4 protein in AD brain cells binds the lipids to AD. In addition, lipid signaling pathways have a crucial role in the cellular homeostasis and depend on specific protein-lipid interactions. The current review focuses on pathological alterations of membrane lipids (cholesterol, glycerophospholipids, sphingolipids) and lipid metabolism in AD and provides insight in the current understanding of biological membranes, their lipid structures and functions, as well as their role as potential therapeutic targets. Novel methods for studying the membrane structure and lipid composition will be reviewed in a broad sense whereas the use of lipid biomarkers for early diagnosis of AD will be shortly summarized. Interactions of Aβ peptides with the cell membrane and different subcellular organelles are reviewed. Next, the details of the most important lipid signaling pathways, including the role of the plasma membrane as stress sensor and its therapeutic applications are given. 4-hydroxy-2-nonenal may play a special role in the initiation of the pathogenesis of AD and thus the “calpain-cathepsin hypothesis” of AD is highlighted. Finally, the most important lipid dietary factors and their possible use and efficacy in the prevention of AD are discussed.

New trends in the pharmacological intervention of PPARs in obesity: Role of natural and synthetic compounds_

2020 ◽  
Vol 28 ◽  
Author(s):  
Seyed Mohammad Nabavi ◽  
Kasi Pandima Devi ◽  
Sethuraman Sathya ◽  
Ana Sanches-Silva ◽  
Listos Joanna ◽  
...  
Keyword(s):  
Tissue Expression ◽  
Health Concern ◽  
Pharmacological Intervention ◽  
Peroxisome Proliferator ◽  
Expression Of Genes ◽  
Ppar Agonists ◽  
Prevalence Of Obesity ◽  
Peroxisome Proliferator Activated Receptors ◽  
Natural And Synthetic

: Obesity is a major health concern for a growing fraction of the population, with the prevalence of obesity and its related metabolic disorders not being fully understood. Over the last decade, many attempts have been undertaken to understand the mechanisms at the basis of this condition, in which the accumulation of fat occurring in adipose tissue, leads to the pathogenesis of obesity related disorders. Among the most recent studies, those on Peroxisome Proliferator Activated Receptors (PPARs) revealed that these nuclear receptor proteins acting as transcription factors, among others, regulate the expression of genes involved in energy, lipid, and glucose metabolisms, and chronic inflammation. The three different isotypes of PPARs, with different tissue expression and ligand binding specificity, exert similar or overlapping functions directly or indirectly linked to obesity. In this study, we reviewed the available scientific reports concerning the PPARs structure and functions, especially in obesity, considering both natural and synthetic ligands and their role in the therapy of obesity and obesity-associated disorders. In the whole, the collected data show that there are both natural and synthetic compounds that show beneficial promising activity as PPAR agonists in chronic diseases related to obesity.

scholarly journals Current Modulation of Guanylate Cyclase Pathway Activity—Mechanism and Clinical Implications

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3418
Author(s):  
Grzegorz Grześk ◽  
Alicja Nowaczyk
Keyword(s):  
Guanylate Cyclase ◽  
Natriuretic Peptides ◽  
Soluble Guanylate Cyclase ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Pharmacological Intervention ◽  
First Line ◽  
Phosphodiesterase Type ◽  
Activity Mechanism

For years, guanylate cyclase seemed to be homogenic and tissue nonspecific enzyme; however, in the last few years, in light of preclinical and clinical trials, it became an interesting target for pharmacological intervention. There are several possible options leading to an increase in cyclic guanosine monophosphate concentrations. The first one is related to the uses of analogues of natriuretic peptides. The second is related to increasing levels of natriuretic peptides by the inhibition of degradation. The third leads to an increase in cyclic guanosine monophosphate concentration by the inhibition of its degradation by the inhibition of phosphodiesterase type 5. The last option involves increasing the concentration of cyclic guanosine monophosphate by the additional direct activation of soluble guanylate cyclase. Treatment based on the modulation of guanylate cyclase function is one of the most promising technologies in pharmacology. Pharmacological intervention is stable, effective and safe. Especially interesting is the role of stimulators and activators of soluble guanylate cyclase, which are able to increase the enzymatic activity to generate cyclic guanosine monophosphate independently of nitric oxide. Moreover, most of these agents are effective in chronic treatment in heart failure patients and pulmonary hypertension, and have potential to be a first line option.

scholarly journals Role of endosomal membrane lipids and NPC2 in cholesterol transfer and membrane fusion

2010 ◽  
Vol 51 (7) ◽  
pp. 1747-1760 ◽  
Author(s):  
Misbaudeen Abdul-Hammed ◽  
Bernadette Breiden ◽  
Matthew A. Adebayo ◽  
Jonathan O. Babalola ◽  
Günter Schwarzmann ◽  
...  
Keyword(s):  
Membrane Fusion ◽  
Membrane Lipids ◽  
Endosomal Membrane

scholarly journals Effects of Rifaximin on Luminal and Wall-Adhered Gut Commensal Microbiota in Mice

2021 ◽  
Vol 22 (2) ◽  
pp. 500
Author(s):  
Marina Ferrer ◽  
Mònica Aguilera ◽  
Vicente Martinez
Keyword(s):  
Fluorescent In Situ Hybridization ◽  
Fragment Length Polymorphism ◽  
Functional Gastrointestinal Disorders ◽  
Antibacterial Properties ◽  
Broad Spectrum Antibiotic ◽  
Commensal Microbiota ◽  
Bacterial Biodiversity ◽  
Rule Out

Rifaximin is a broad-spectrum antibiotic that ameliorates symptomatology in inflammatory/functional gastrointestinal disorders. We assessed changes in gut commensal microbiota (GCM) and Toll-like receptors (TLRs) associated to rifaximin treatment in mice. Adult C57BL/6NCrl mice were treated (7/14 days) with rifaximin (50/150 mg/mouse/day, PO). Luminal and wall-adhered ceco-colonic GCM were characterized by fluorescent in situ hybridization (FISH) and microbial profiles determined by terminal restriction fragment length polymorphism (T-RFLP). Colonic expression of TLR2/3/4/5/7 and immune-related markers was assessed (RT-qPCR). Regardless the period of treatment or the dose, rifaximin did not alter total bacterial counts or bacterial biodiversity. Only a modest increase in Bacteroides spp. (150 mg/1-week treatment) was detected. In control conditions, only Clostridium spp. and Bifidobacterium spp. were found attached to the colonic epithelium. Rifaximin showed a tendency to favour their adherence after a 1-week, but not 2-week, treatment period. Minor up-regulation in TLRs expression was observed. Only the 50 mg dose for 1-week led to a significant increase (by 3-fold) in TLR-4 expression. No changes in the expression of immune-related markers were observed. Rifaximin, although its antibacterial properties, induces minor changes in luminal and wall-adhered GCM in healthy mice. Moreover, no modulation of TLRs or local immune systems was observed. These findings, in normal conditions, do not rule out a modulatory role of rifaximin in inflammatory and or dysbiotic states of the gut.

scholarly journals Learning Speech Production and Perception through Sensorimotor Interactions

2020 ◽  
Author(s):  
Shihab Shamma ◽  
Prachi Patel ◽  
Shoutik Mukherjee ◽  
Guilhem Marion ◽  
Bahar Khalighinejad ◽  
...  
Keyword(s):  
Vocal Tract ◽  
Human Subjects ◽  
Motor Task ◽  
Neural Processes ◽  
Mathematical Simulations ◽  
Predictive Role ◽  
Sensorimotor Interactions ◽  
Forward Projection ◽  
Cortical Regions

Abstract Action and Perception are closely linked in many behaviors necessitating a close coordination between sensory and motor neural processes so as to achieve a well-integrated smoothly evolving task performance. To investigate the detailed nature of these sensorimotor interactions, and their role in learning and executing the skilled motor task of speaking, we analyzed ECoG recordings of responses in the high-γ band (70 Hz-150 Hz) in human subjects while they listened to, spoke, or silently articulated speech. We found elaborate spectrotemporally-modulated neural activity projecting in both forward (motor-to-sensory) and inverse directions between the higher-auditory and motor cortical regions engaged during speaking. Furthermore, mathematical simulations demonstrate a key role for the forward projection in learning to control the vocal tract, beyond its commonly-postulated predictive role during execution. These results therefore offer a broader view of the functional role of the ubiquitous forward projection as an important ingredient in learning, rather than just control, of skilled sensorimotor tasks.

scholarly journals Depdc5 deficiency exacerbates alcohol-induced hepatic steatosis via suppression of PPARα pathway

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Lin Xu ◽  
Xinge Zhang ◽  
Yue Xin ◽  
Jie Ma ◽  
Chenyan Yang ◽  
...  
Keyword(s):  
Liver Injury ◽  
Hepatic Steatosis ◽  
Liver Steatosis ◽  
Pharmacological Intervention ◽  
Acid Oxidation ◽  
Peroxisome Proliferator ◽  
Pathological Effect ◽  
Mtorc1 Pathway

AbstractAlcohol-related liver disease (ALD), a condition caused by alcohol overconsumption, occurs in three stages of liver injury including steatosis, hepatitis, and cirrhosis. DEP domain-containing protein 5 (DEPDC5), a component of GAP activities towards Rags 1 (GATOR1) complex, is a repressor of amino acid-sensing branch of the mammalian target of rapamycin complex 1 (mTORC1) pathway. In the current study, we found that aberrant activation of mTORC1 was likely attributed to the reduction of DEPDC5 in the livers of ethanol-fed mice or ALD patients. To further define the in vivo role of DEPDC5 in ALD development, we generated Depdc5 hepatocyte-specific knockout mouse model (Depdc5-LKO) in which mTORC1 pathway was constitutively activated through loss of the inhibitory effect of GATOR1. Hepatic Depdc5 ablation leads to mild hepatomegaly and liver injury and protects against diet-induced liver steatosis. In contrast, ethanol-fed Depdc5-LKO mice developed severe hepatic steatosis and inflammation. Pharmacological intervention with Torin 1 suppressed mTORC1 activity and remarkably ameliorated ethanol-induced hepatic steatosis and inflammation in both control and Depdc5-LKO mice. The pathological effect of sustained mTORC1 activity in ALD may be attributed to the suppression of peroxisome proliferator activated receptor α (PPARα), the master regulator of fatty acid oxidation in hepatocytes, because fenofibrate (PPARα agonist) treatment reverses ethanol-induced liver steatosis and inflammation in Depdc5-LKO mice. These findings provide novel insights into the in vivo role of hepatic DEPDC5 in the development of ALD.

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