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Journal of Environmental Sciences... May 2023Copper (Cu) exists in a variety of forms in different aquatic environments, and affects their bioavailability. In this study we provide a systematic review on toxicity...
Copper (Cu) exists in a variety of forms in different aquatic environments, and affects their bioavailability. In this study we provide a systematic review on toxicity of Cu which focuses on identifying evidence in the mechanisms of Cu toxicity, and apply an adverse outcome pathway (AOP) analysis to identify multiple potential mechanisms and their interactions of Cu toxicity to fish. This analysis process included the mechanisms of behavior toxicant, oxidative toxicant, ion regulation disruption toxicity, as well as endocrine disruption toxicity. It was found that at low levels of Cu exposure, swimming, avoid predators, locating prey and other sensory functions will be impaired, and the organism will suffer from metabolic alkalosis and respiratory acidosis following the inhibition of the carbonic anhydrase active. The main pathway of acute toxicity of Cu to fish is the inhibition of the Na/K-ATPase enzyme, and lead to reduced intracellular sodium absorption, as well as Cu-induced increased cell permeability, in turn resulting in increased sodium ion loss, leading to cardiovascular collapse and respiratory insufficiency. The endocrine disruption toxicity of Cu to fish caused growth inhibition and reproductive reduction. In addition, there are several key pathways of Cu toxicity that are affected by hardness (e.g., Ca) and intracellular DOC concentrations, including inhibiting Cu-induction, improving branchial gas exchange, altering membrane transport functions, decreasing Na loss, and increasing Na uptake. The results of the AOP analysis will provide a robust framework for future directed research on the mechanisms of Cu toxicity.
Topics: Animals; Copper; Adverse Outcome Pathways; Biological Availability; Water Pollutants, Chemical; Sodium; Fishes; Ions
PubMed: 36522080
DOI: 10.1016/j.jes.2022.06.002 -
International Journal of Molecular... Oct 2021The Epithelial Sodium Channel/Degenerin (ENaC/DEG) family is a superfamily of sodium-selective channels that play diverse and important physiological roles in a wide...
The Epithelial Sodium Channel/Degenerin (ENaC/DEG) family is a superfamily of sodium-selective channels that play diverse and important physiological roles in a wide variety of animal species. Despite their differences, they share a high homology in the pore region in which the ion discrimination takes place. Although ion selectivity has been studied for decades, the mechanisms underlying this selectivity for trimeric channels, and particularly for the ENaC/DEG family, are still poorly understood. This systematic review follows PRISMA guidelines and aims to determine the main components that govern ion selectivity in the ENaC/DEG family. In total, 27 papers from three online databases were included according to specific exclusion and inclusion criteria. It was found that the G/SxS selectivity filter (glycine/serine, non-conserved residue, serine) and other well conserved residues play a crucial role in ion selectivity. Depending on the ion type, residues with different properties are involved in ion permeability. For lithium against sodium, aromatic residues upstream of the selectivity filter seem to be important, whereas for sodium against potassium, negatively charged residues downstream of the selectivity filter seem to be important. This review provides new perspectives for further studies to unravel the mechanisms of ion selectivity.
Topics: Amiloride; Animals; Epithelial Sodium Channels; Humans; Ion Transport; Lithium; Molecular Dynamics Simulation; Mutagenesis, Site-Directed; Protein Structure, Quaternary; Sodium
PubMed: 34681656
DOI: 10.3390/ijms222010998 -
Annals of the New York Academy of... Sep 2021Many aspects of chemistry and biology are mediated by electromagnetic field (EMF) interactions. The central nervous system (CNS) is particularly sensitive to EMF...
Many aspects of chemistry and biology are mediated by electromagnetic field (EMF) interactions. The central nervous system (CNS) is particularly sensitive to EMF stimuli. Studies have explored the direct effect of different EMFs on the electrical properties of neurons in the last two decades, particularly focusing on the role of voltage-gated ion channels (VGCs). This work aims to systematically review published evidence in the last two decades detailing the effects of EMFs on neuronal ion channels as per the PRISM guidelines. Following a predetermined exclusion and inclusion criteria, 22 papers were included after searches on three online databases. Changes in calcium homeostasis, attributable to the voltage-gated calcium channels, were found to be the most commonly reported result of EMF exposure. EMF effects on the neuronal landscape appear to be diverse and greatly dependent on parameters, such as the field's frequency, exposure time, and intrinsic properties of the irradiated tissue, such as the expression of VGCs. Here, we systematically clarify how neuronal ion channels are particularly affected and differentially modulated by EMFs at multiple levels, such as gating dynamics, ion conductance, concentration in the membrane, and gene and protein expression. Ion channels represent a major transducer for EMF-related effects on the CNS.
Topics: Animals; Biological Transport; Biomarkers; Brain; Electromagnetic Fields; Electrophysiological Phenomena; Humans; Ion Channel Gating; Ion Channels; Ions; Neurons; Signal Transduction
PubMed: 33945157
DOI: 10.1111/nyas.14597 -
The Cochrane Database of Systematic... Apr 2007Cystic fibrosis is caused by a defective gene encoding a protein called the cystic fibrosis transmembrane conductance regulator (CFTR), and is characterised by chronic... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Cystic fibrosis is caused by a defective gene encoding a protein called the cystic fibrosis transmembrane conductance regulator (CFTR), and is characterised by chronic lung infection resulting in inflammation and progressive lung damage that results in a reduced life expectancy.
OBJECTIVES
To determine whether topical CFTR gene replacement therapy to the lungs in people with cystic fibrosis is associated with improvements in clinical outcomes, and to assess any adverse effects.
SEARCH STRATEGY
We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches, handsearching relevant journals and abstract books of conference proceedings. Date of most recent search: February 2007
SELECTION CRITERIA
Randomised controlled trials comparing topical CFTR gene delivery to the lung, using either viral or non-viral delivery systems, with placebo or an alternative delivery system in people with confirmed cystic fibrosis.
DATA COLLECTION AND ANALYSIS
The authors independently extracted data and assessed study quality. Authors of included studies were contacted and asked for any available additional data. Meta-analysis was limited due to differing study designs.
MAIN RESULTS
Three randomised controlled trials met the inclusion criteria for this review, involving a total of 155 participants. Thirteen studies were excluded. The included studies differed in terms of CFTR gene replacement agent and study design, which limited the meta-analysis. Although the first Moss study reported a significant improvement in respiratory function (FEV(1)) 30 days after participants had received their first dose of gene therapy agent, this finding was not confirmed in their larger second study or in our meta-analysis.In participants who received the CFTR gene transfer agents in the Alton study, "influenza-like" symptoms were found (relative risk 7.00 (95% confidence interval (CI) 1.10 to 44.61)). There were no other significant increases in adverse events in any of the studies. Alton measured ion transport in the lower airways and demonstrated significant changes toward normal values in the participants who received gene transfer agents (P < 0.0001), weighted mean difference 6.86 (95% CI of 3.77 to 9.95). In these participants there was also evidence of increased salt transport in cells obtained by brushing the lower airway. These outcomes, whilst important, are not of direct clinical relevance.
AUTHORS' CONCLUSIONS
There is currently no evidence to support the use of CFTR gene transfer reagents as a treatment for lung disease in people with cystic fibrosis. Future studies need to investigate clinically important outcome measures.
Topics: Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Gene Transfer Techniques; Genetic Therapy; Humans; Randomized Controlled Trials as Topic; Respiratory Function Tests
PubMed: 17443603
DOI: 10.1002/14651858.CD005599.pub2 -
Drug Delivery Nov 2018To achieve sufficient blood-brain barrier (BBB), penetration is one of the biggest challenges in the development of diagnostic and therapeutic for central nervous system... (Meta-Analysis)
Meta-Analysis
Borneol, a messenger agent, improves central nervous system drug delivery through enhancing blood-brain barrier permeability: a preclinical systematic review and meta-analysis.
To achieve sufficient blood-brain barrier (BBB), penetration is one of the biggest challenges in the development of diagnostic and therapeutic for central nervous system (CNS) disorders. Here, we conducted a systematic review and meta-analysis to assess the preclinical evidence and possible mechanisms of borneol for improving co-administration of CNS drug delivery in animal models. The electronic literature search was conducted in six databases. Fifty-eight studies with 63 comparisons involved 1137 animals were included. Among 47 studies reporting the assessments of CNS drug concentration, 45 studies showed the significant effects of borneol for improving CNS drug delivery (p<.05), whereas 2 studies showed no difference (p>.05). Nineteen comparisons showed borneol up-regulated BBB permeability (p<.05) using brain EB content (n = 8), Rh 123 content (n = 4), brain imaging agent content (n = 2), brain water content (n = 1) and observing ultrastructure of BBB (n = 4), whereas three studies showed no difference or unclear results. Seven studies reported the safety, in which one study showed borneol was reversible changes in the BBB penetration; six studies showed borneol did not increase co-administration of blood drugs concentration of peripheral tissues (p > .05). Effects of borneol are closely associated with inhibition of efflux protein function, releasement of tight junction protein, increasement of vasodilatory neurotransmitters, and inhibition of active transport by ion channels. In conclusion, borneol is a promising candidate for CNS drug delivery, mainly through mediating a multi-targeted BBB permeability.
Topics: Animals; Blood-Brain Barrier; Camphanes; Central Nervous System Agents; Central Nervous System Diseases; Drug Carriers; Female; Humans; Male; Permeability
PubMed: 30334462
DOI: 10.1080/10717544.2018.1486471 -
Medical Oncology (Northwood, London,... Oct 2018Metabolic alterations in the tumor microenvironment have a complex effect on cancer progression. Extracellular acidity is a consequence of metabolic switch in cancer and...
Metabolic alterations in the tumor microenvironment have a complex effect on cancer progression. Extracellular acidity is a consequence of metabolic switch in cancer and results in cell phenotypes with higher resistance to chemotherapeutics. However, mechanisms underlying the relationship between the extracellular acidity and chemoresistance are not clearly understood. This systematic review was carried out by searching the databases PubMed and EMBASE using the keywords "cancer" and "acidosis" or "acidic" and "chemoresistance" or "drug resistance." In vitro and in vivo studies that evaluated the effects of acidification of the tumor microenvironment on chemotherapeutic treatments were included. Literature reviews, letters to the editor, and articles that were not published in English were excluded. The search resulted in a total of 352 articles. After discarding 75 duplicate references, 277 articles were analyzed by sequentially reading through their titles, abstracts, and finally full-text. A total of 14 articles was selected. Acidification of the tumor microenvironment can trigger resistance through different mechanisms, such as increase in drug efflux transporters, inhibition of proton pumps, induction of the unfolded protein response (UPR), and cellular autophagy.
Topics: Animals; Antineoplastic Agents; Autophagy; Drug Resistance, Neoplasm; Humans; Hydrogen-Ion Concentration; Membrane Transport Proteins; Neoplasms; Tumor Microenvironment; Unfolded Protein Response
PubMed: 30377828
DOI: 10.1007/s12032-018-1214-4