Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
Mais filtros

Base de dados
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Biochim Biophys Acta ; 1861(11): 1808-1815, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27600289

RESUMO

Phosphatidylinositol analogs (PIAs) were originally designed to bind competitively to the Akt PH domain and prevent membrane translocation and activation. d-3-Deoxy-dioctanoylphosphatidylinositol (d-3-deoxy-diC8PI), but not compounds with altered inositol stereochemistry (e.g., l-3-deoxy-diC8PI and l-3,5-dideoxy-diC8PI), is cytotoxic. However, high resolution NMR field cycling relaxometry shows that both cytotoxic and non-toxic PIAs bind to the Akt1 PH domain at the site occupied by the cytotoxic alkylphospholipid perifosine. This suggests that another mechanism for cytotoxicity must account for the difference in efficacy of the synthetic short-chain PIAs. In MCF-7 breast cancer cells, with little constitutively active Akt, d-3-deoxy-diC8PI (but not l-compounds) decreases viability concomitant with increased cleavage of PARP and caspase 9, indicative of apoptosis. d-3-Deoxy-diC8PI also induces a decrease in endogenous levels of cyclins D1 and D3 and blocks downstream retinoblastoma protein phosphorylation. siRNA-mediated depletion of cyclin D1, but not cyclin D3, reduces MCF-7 cell proliferation. Thus, growth arrest and cytotoxicity induced by the soluble d-3-deoxy-diC8PI occur by a mechanism that involves downregulation of the D-type cyclin-pRb pathway independent of its interaction with Akt. This ability to downregulate D-type cyclins contributes, at least in part, to the anti-proliferative activity of d-3-deoxy-diC8PI and may be a common feature of other cytotoxic phospholipids.


Assuntos
Neoplasias da Mama/patologia , Ciclina D1/metabolismo , Regulação para Baixo/efeitos dos fármacos , Ácidos Fosfatídicos/farmacologia , Fosfatidilinositóis/farmacologia , Proteína do Retinoblastoma/metabolismo , Transdução de Sinais/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Feminino , Humanos , Células MCF-7 , Espectroscopia de Ressonância Magnética , Ácidos Fosfatídicos/química , Fosfatidilinositóis/química , Fosforilação/efeitos dos fármacos , Domínios de Homologia à Plecstrina , Proteínas Proto-Oncogênicas c-akt/química , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Interferente Pequeno/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
2.
J Biol Chem ; 289(10): 7011-7024, 2014 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-24469453

RESUMO

Bacterially derived lipopolysaccharide (LPS) stimulates naive B lymphocytes to differentiate into immunoglobulin (Ig)-secreting plasma cells. Differentiation of B lymphocytes is characterized by a proliferative phase followed by expansion of the intracellular membrane secretory network to support Ig production. A key question in lymphocyte biology is how naive B cells reprogram metabolism to support de novo lipogenesis necessary for proliferation and expansion of the endomembrane network in response to LPS. We report that extracellularly acquired glucose is metabolized, in part, to support de novo lipogenesis in response to LPS stimulation of splenic B lymphocytes. LPS stimulation leads to increased levels of endogenous ATP-citrate lyase (ACLY), and this is accompanied by increased ACLY enzymatic activity. ACLY produces cytosolic acetyl-CoA from mitochondrially derived citrate. Inhibition of ACLY activity in LPS-stimulated B cells with the selective inhibitor 2-hydroxy-N-arylbenzenesulfonamide (compound-9; C-9) blocks glucose incorporation into de novo lipid biosynthesis, including cholesterol, free fatty acids, and neutral and acidic phospholipids. Moreover, inhibition of ACLY activity in splenic B cells results in inhibition of proliferation and defective endomembrane expansion and reduced expression of CD138 and Blimp-1, markers for plasma-like B cell differentiation. ACLY activity is also required for LPS-induced IgM production in CH12 B lymphoma cells. These data demonstrate that ACLY mediates glucose-dependent de novo lipogenesis in response to LPS signaling and identify a role for ACLY in several phenotypic changes that define plasma cell differentiation.


Assuntos
ATP Citrato (pro-S)-Liase/fisiologia , Linfócitos B/imunologia , Glucose/metabolismo , Lipogênese/imunologia , Lipopolissacarídeos/imunologia , Ativação Linfocitária , ATP Citrato (pro-S)-Liase/antagonistas & inibidores , Animais , Linfócitos B/citologia , Diferenciação Celular , Camundongos , Camundongos Endogâmicos BALB C
3.
Analyst ; 140(1): 39-58, 2015 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-25279400

RESUMO

The evolution of micro/nanoelectronics technology, including the shrinking of devices and integrated circuit components, has included the miniaturization of linear and coaxial structures to micro/nanoscale dimensions. This reduction in the size of coaxial structures may offer advantages to existing technologies and benefit the exploration and development of new technologies. The reduction in the size of coaxial structures has been realized with various permutations between metals, semiconductors and dielectrics for the core, shield, and annulus. This review will focus on fabrication schemes of arrays of metal - nonmetal - metal nanocoax structures using non-template and template methods, followed by possible applications. The performance and scientific advantages associated with nanocoax-based optical devices including waveguides, negative refractive index materials, light emitting diodes, and photovoltaics are presented. In addition, benefits and challenges that accrue from the application of novel nanocoax structures in energy storage, electronic and sensing devices are summarized.


Assuntos
Técnicas Eletroquímicas , Nanoestruturas/análise , Dispositivos Ópticos
4.
Ann Glob Health ; 90(1): 2, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38223653

RESUMO

Background: Rwanda, like many countries in sub-Saharan Africa, is still relatively early in development. Industrialization and urbanization are major drivers of the county's economic growth. Rwanda is also undergoing an epidemiological transition, from a pattern of morbidity and mortality dominated by infectious diseases to a pattern shaped by non-communicable diseases (NCDs). The rise in NCDs is due, in part, to increasing exposures to environmental hazards. These include emissions from the growing number of motor vehicles and toxic occupational exposures. Cardiovascular disease (CVD) is now an increasingly important cause of death in Rwanda, and ambient air pollution is a CVD risk factor of growing importance. Objectives: To quantify the burden of CVD attributable to air pollution in Rwanda and identify opportunities for prevention and control of air pollution and pollution-related disease. Methods: We relied on the 2019 Global Burden of Disease (GBD) study for information on levels, sources, and trends in household and ambient air pollution and the burden of pollution-related disease in Rwanda. Information on pollution sources was obtained from the Health Effects Institute State of Global Air 2019 report. Findings: An estimated 3,477 deaths (95% Uncertainty Interval [UI]: 2,500-4,600) in Rwanda in 2019 were attributable to air pollution-related CVD. Of these, 689 (UI: 283-1,300) deaths were from ambient air pollution-related CVD, while 2,788 (UI: 1,800-3,800) deaths were from household air pollution-related CVD. Conclusion: Rwanda is experiencing increased rates of disease and premature death from NCDs, including CVD, as the country grows economically. While household air pollution is still the top pollution-related cause of disease and premature death, rising levels of ambient air pollution are an increasingly important CVD risk factor. Recommendation: Actions taken now to curb rising levels of ambient air pollution will improve health, reduce CVD, increase longevity, and produce great economic benefit for Rwanda. The single most effective intervention against air pollution will be a rapid nationwide transition to renewable energy. We recommend additionally that Rwanda prioritize air pollution prevention and control, establish a robust, nationwide air monitoring network, support research on the health effects of air pollutants, and build national research capacity. The allocation of increased resources for rural and urban public health and health care will complement air pollution control measures and further reduce CVD. To incentivize a rapid transition to renewable energy in Rwanda and other nations, we recommend the creation of a new Global Green Development Fund.


Assuntos
Poluição do Ar , Doenças Cardiovasculares , Doenças Transmissíveis , Humanos , Doenças Cardiovasculares/epidemiologia , Expectativa de Vida , Ruanda/epidemiologia , Poluição do Ar/efeitos adversos
5.
Anal Chem ; 85(21): 10040-4, 2013 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-24090275

RESUMO

We have used a facile polymer imprint process to fabricate a three-dimensional electrochemical nanosensor, the sensitivity of which is two decades higher than that of planar controls. The device is composed of an array of vertically oriented nanoscale coaxial electrodes, with the coax cores and shields serving as integrated working and counter electrodes, respectively, each with a nanoscale separation gap (coax annulus width). Arrays of ~10(6) devices per square millimeter were prepared with different gaps, with smaller gaps yielding higher sensitivity. A coax-based sensor with a 100 nm gap was found to have sensitivity 90 times greater than that of a planar sensor control, which had conventional millimeter-scale electrode gap spacing. We suggest that this enhancement is due to the combination of rapid diffusion of molecules between the closely spaced electrodes and the large number of nanoscale electrochemical cells operating in parallel, both of which enhance current per unit surface area compared to planar or other nanostructured devices.


Assuntos
Técnicas Eletroquímicas/instrumentação , Nanotecnologia , Microscopia Eletrônica de Varredura
6.
Biochem J ; 448(1): 165-9, 2012 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-22994860

RESUMO

Signals derived from the BCR (B-cell antigen receptor) control survival, development and antigenic responses. One mechanism by which BCR signals may mediate these responses is by regulating cell metabolism. Indeed, the bioenergetic demands of naïve B-cells increase following BCR engagement and are characterized by a metabolic switch to aerobic glycolysis; however, the signalling pathways involved in this metabolic reprogramming are poorly defined. The PKC (protein kinase C) family plays an integral role in B-cell survival and antigenic responses. Using pharmacological inhibition and mice deficient in PKCß, we demonstrate an essential role of PKCß in BCR-induced glycolysis in B-cells. In contrast, mice deficient in PKCδ exhibit glycolytic rates comparable with those of wild-type B-cells following BCR cross-linking. The induction of several glycolytic genes following BCR engagement is impaired in PKCß-deficient B-cells. Moreover, blocking glycolysis results in decreased survival of B-cells despite BCR engagement. The results establish a definitive role for PKCß in the metabolic switch to glycolysis following BCR engagement of naïve B-cells.


Assuntos
Linfócitos B/enzimologia , Glicólise/fisiologia , Ativação Linfocitária/fisiologia , Proteína Quinase C/fisiologia , Receptores de Antígenos de Linfócitos B/imunologia , Tirosina Quinase da Agamaglobulinemia , Agamaglobulinemia/genética , Agamaglobulinemia/metabolismo , Animais , Linfócitos B/imunologia , Indução Enzimática , Regulação da Expressão Gênica , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Transportador de Glucose Tipo 1/biossíntese , Transportador de Glucose Tipo 1/genética , Glicólise/genética , Tolerância Imunológica , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/deficiência , Proteína Quinase C/genética , Proteína Quinase C beta , Proteína Quinase C-delta/deficiência , Proteína Quinase C-delta/genética , Proteínas Tirosina Quinases/deficiência , Proteínas Tirosina Quinases/genética , Transdução de Sinais
8.
Ann Glob Health ; 89(1): 23, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36969097

RESUMO

Background: Plastics have conveyed great benefits to humanity and made possible some of the most significant advances of modern civilization in fields as diverse as medicine, electronics, aerospace, construction, food packaging, and sports. It is now clear, however, that plastics are also responsible for significant harms to human health, the economy, and the earth's environment. These harms occur at every stage of the plastic life cycle, from extraction of the coal, oil, and gas that are its main feedstocks through to ultimate disposal into the environment. The extent of these harms not been systematically assessed, their magnitude not fully quantified, and their economic costs not comprehensively counted. Goals: The goals of this Minderoo-Monaco Commission on Plastics and Human Health are to comprehensively examine plastics' impacts across their life cycle on: (1) human health and well-being; (2) the global environment, especially the ocean; (3) the economy; and (4) vulnerable populations-the poor, minorities, and the world's children. On the basis of this examination, the Commission offers science-based recommendations designed to support development of a Global Plastics Treaty, protect human health, and save lives. Report Structure: This Commission report contains seven Sections. Following an Introduction, Section 2 presents a narrative review of the processes involved in plastic production, use, and disposal and notes the hazards to human health and the environment associated with each of these stages. Section 3 describes plastics' impacts on the ocean and notes the potential for plastic in the ocean to enter the marine food web and result in human exposure. Section 4 details plastics' impacts on human health. Section 5 presents a first-order estimate of plastics' health-related economic costs. Section 6 examines the intersection between plastic, social inequity, and environmental injustice. Section 7 presents the Commission's findings and recommendations. Plastics: Plastics are complex, highly heterogeneous, synthetic chemical materials. Over 98% of plastics are produced from fossil carbon- coal, oil and gas. Plastics are comprised of a carbon-based polymer backbone and thousands of additional chemicals that are incorporated into polymers to convey specific properties such as color, flexibility, stability, water repellence, flame retardation, and ultraviolet resistance. Many of these added chemicals are highly toxic. They include carcinogens, neurotoxicants and endocrine disruptors such as phthalates, bisphenols, per- and poly-fluoroalkyl substances (PFAS), brominated flame retardants, and organophosphate flame retardants. They are integral components of plastic and are responsible for many of plastics' harms to human health and the environment.Global plastic production has increased almost exponentially since World War II, and in this time more than 8,300 megatons (Mt) of plastic have been manufactured. Annual production volume has grown from under 2 Mt in 1950 to 460 Mt in 2019, a 230-fold increase, and is on track to triple by 2060. More than half of all plastic ever made has been produced since 2002. Single-use plastics account for 35-40% of current plastic production and represent the most rapidly growing segment of plastic manufacture.Explosive recent growth in plastics production reflects a deliberate pivot by the integrated multinational fossil-carbon corporations that produce coal, oil and gas and that also manufacture plastics. These corporations are reducing their production of fossil fuels and increasing plastics manufacture. The two principal factors responsible for this pivot are decreasing global demand for carbon-based fuels due to increases in 'green' energy, and massive expansion of oil and gas production due to fracking.Plastic manufacture is energy-intensive and contributes significantly to climate change. At present, plastic production is responsible for an estimated 3.7% of global greenhouse gas emissions, more than the contribution of Brazil. This fraction is projected to increase to 4.5% by 2060 if current trends continue unchecked. Plastic Life Cycle: The plastic life cycle has three phases: production, use, and disposal. In production, carbon feedstocks-coal, gas, and oil-are transformed through energy-intensive, catalytic processes into a vast array of products. Plastic use occurs in every aspect of modern life and results in widespread human exposure to the chemicals contained in plastic. Single-use plastics constitute the largest portion of current use, followed by synthetic fibers and construction.Plastic disposal is highly inefficient, with recovery and recycling rates below 10% globally. The result is that an estimated 22 Mt of plastic waste enters the environment each year, much of it single-use plastic and are added to the more than 6 gigatons of plastic waste that have accumulated since 1950. Strategies for disposal of plastic waste include controlled and uncontrolled landfilling, open burning, thermal conversion, and export. Vast quantities of plastic waste are exported each year from high-income to low-income countries, where it accumulates in landfills, pollutes air and water, degrades vital ecosystems, befouls beaches and estuaries, and harms human health-environmental injustice on a global scale. Plastic-laden e-waste is particularly problematic. Environmental Findings: Plastics and plastic-associated chemicals are responsible for widespread pollution. They contaminate aquatic (marine and freshwater), terrestrial, and atmospheric environments globally. The ocean is the ultimate destination for much plastic, and plastics are found throughout the ocean, including coastal regions, the sea surface, the deep sea, and polar sea ice. Many plastics appear to resist breakdown in the ocean and could persist in the global environment for decades. Macro- and micro-plastic particles have been identified in hundreds of marine species in all major taxa, including species consumed by humans. Trophic transfer of microplastic particles and the chemicals within them has been demonstrated. Although microplastic particles themselves (>10 µm) appear not to undergo biomagnification, hydrophobic plastic-associated chemicals bioaccumulate in marine animals and biomagnify in marine food webs. The amounts and fates of smaller microplastic and nanoplastic particles (MNPs <10 µm) in aquatic environments are poorly understood, but the potential for harm is worrying given their mobility in biological systems. Adverse environmental impacts of plastic pollution occur at multiple levels from molecular and biochemical to population and ecosystem. MNP contamination of seafood results in direct, though not well quantified, human exposure to plastics and plastic-associated chemicals. Marine plastic pollution endangers the ocean ecosystems upon which all humanity depends for food, oxygen, livelihood, and well-being. Human Health Findings: Coal miners, oil workers and gas field workers who extract fossil carbon feedstocks for plastic production suffer increased mortality from traumatic injury, coal workers' pneumoconiosis, silicosis, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer. Plastic production workers are at increased risk of leukemia, lymphoma, hepatic angiosarcoma, brain cancer, breast cancer, mesothelioma, neurotoxic injury, and decreased fertility. Workers producing plastic textiles die of bladder cancer, lung cancer, mesothelioma, and interstitial lung disease at increased rates. Plastic recycling workers have increased rates of cardiovascular disease, toxic metal poisoning, neuropathy, and lung cancer. Residents of "fenceline" communities adjacent to plastic production and waste disposal sites experience increased risks of premature birth, low birth weight, asthma, childhood leukemia, cardiovascular disease, chronic obstructive pulmonary disease, and lung cancer.During use and also in disposal, plastics release toxic chemicals including additives and residual monomers into the environment and into people. National biomonitoring surveys in the USA document population-wide exposures to these chemicals. Plastic additives disrupt endocrine function and increase risk for premature births, neurodevelopmental disorders, male reproductive birth defects, infertility, obesity, cardiovascular disease, renal disease, and cancers. Chemical-laden MNPs formed through the environmental degradation of plastic waste can enter living organisms, including humans. Emerging, albeit still incomplete evidence indicates that MNPs may cause toxicity due to their physical and toxicological effects as well as by acting as vectors that transport toxic chemicals and bacterial pathogens into tissues and cells.Infants in the womb and young children are two populations at particularly high risk of plastic-related health effects. Because of the exquisite sensitivity of early development to hazardous chemicals and children's unique patterns of exposure, plastic-associated exposures are linked to increased risks of prematurity, stillbirth, low birth weight, birth defects of the reproductive organs, neurodevelopmental impairment, impaired lung growth, and childhood cancer. Early-life exposures to plastic-associated chemicals also increase the risk of multiple non-communicable diseases later in life. Economic Findings: Plastic's harms to human health result in significant economic costs. We estimate that in 2015 the health-related costs of plastic production exceeded $250 billion (2015 Int$) globally, and that in the USA alone the health costs of disease and disability caused by the plastic-associated chemicals PBDE, BPA and DEHP exceeded $920 billion (2015 Int$). Plastic production results in greenhouse gas (GHG) emissions equivalent to 1.96 gigatons of carbon dioxide (CO2e) annually. Using the US Environmental Protection Agency's (EPA) social cost of carbon metric, we estimate the annual costs of these GHG emissions to be $341 billion (2015 Int$).These costs, large as they are, almost certainly underestimate the full economic losses resulting from plastics' negative impacts on human health and the global environment. All of plastics' economic costs-and also its social costs-are externalized by the petrochemical and plastic manufacturing industry and are borne by citizens, taxpayers, and governments in countries around the world without compensation. Social Justice Findings: The adverse effects of plastics and plastic pollution on human health, the economy and the environment are not evenly distributed. They disproportionately affect poor, disempowered, and marginalized populations such as workers, racial and ethnic minorities, "fenceline" communities, Indigenous groups, women, and children, all of whom had little to do with creating the current plastics crisis and lack the political influence or the resources to address it. Plastics' harmful impacts across its life cycle are most keenly felt in the Global South, in small island states, and in disenfranchised areas in the Global North. Social and environmental justice (SEJ) principles require reversal of these inequitable burdens to ensure that no group bears a disproportionate share of plastics' negative impacts and that those who benefit economically from plastic bear their fair share of its currently externalized costs. Conclusions: It is now clear that current patterns of plastic production, use, and disposal are not sustainable and are responsible for significant harms to human health, the environment, and the economy as well as for deep societal injustices.The main driver of these worsening harms is an almost exponential and still accelerating increase in global plastic production. Plastics' harms are further magnified by low rates of recovery and recycling and by the long persistence of plastic waste in the environment.The thousands of chemicals in plastics-monomers, additives, processing agents, and non-intentionally added substances-include amongst their number known human carcinogens, endocrine disruptors, neurotoxicants, and persistent organic pollutants. These chemicals are responsible for many of plastics' known harms to human and planetary health. The chemicals leach out of plastics, enter the environment, cause pollution, and result in human exposure and disease. All efforts to reduce plastics' hazards must address the hazards of plastic-associated chemicals. Recommendations: To protect human and planetary health, especially the health of vulnerable and at-risk populations, and put the world on track to end plastic pollution by 2040, this Commission supports urgent adoption by the world's nations of a strong and comprehensive Global Plastics Treaty in accord with the mandate set forth in the March 2022 resolution of the United Nations Environment Assembly (UNEA).International measures such as a Global Plastics Treaty are needed to curb plastic production and pollution, because the harms to human health and the environment caused by plastics, plastic-associated chemicals and plastic waste transcend national boundaries, are planetary in their scale, and have disproportionate impacts on the health and well-being of people in the world's poorest nations. Effective implementation of the Global Plastics Treaty will require that international action be coordinated and complemented by interventions at the national, regional, and local levels.This Commission urges that a cap on global plastic production with targets, timetables, and national contributions be a central provision of the Global Plastics Treaty. We recommend inclusion of the following additional provisions:The Treaty needs to extend beyond microplastics and marine litter to include all of the many thousands of chemicals incorporated into plastics.The Treaty needs to include a provision banning or severely restricting manufacture and use of unnecessary, avoidable, and problematic plastic items, especially single-use items such as manufactured plastic microbeads.The Treaty needs to include requirements on extended producer responsibility (EPR) that make fossil carbon producers, plastic producers, and the manufacturers of plastic products legally and financially responsible for the safety and end-of-life management of all the materials they produce and sell.The Treaty needs to mandate reductions in the chemical complexity of plastic products; health-protective standards for plastics and plastic additives; a requirement for use of sustainable non-toxic materials; full disclosure of all components; and traceability of components. International cooperation will be essential to implementing and enforcing these standards.The Treaty needs to include SEJ remedies at each stage of the plastic life cycle designed to fill gaps in community knowledge and advance both distributional and procedural equity.This Commission encourages inclusion in the Global Plastic Treaty of a provision calling for exploration of listing at least some plastic polymers as persistent organic pollutants (POPs) under the Stockholm Convention.This Commission encourages a strong interface between the Global Plastics Treaty and the Basel and London Conventions to enhance management of hazardous plastic waste and slow current massive exports of plastic waste into the world's least-developed countries.This Commission recommends the creation of a Permanent Science Policy Advisory Body to guide the Treaty's implementation. The main priorities of this Body would be to guide Member States and other stakeholders in evaluating which solutions are most effective in reducing plastic consumption, enhancing plastic waste recovery and recycling, and curbing the generation of plastic waste. This Body could also assess trade-offs among these solutions and evaluate safer alternatives to current plastics. It could monitor the transnational export of plastic waste. It could coordinate robust oceanic-, land-, and air-based MNP monitoring programs.This Commission recommends urgent investment by national governments in research into solutions to the global plastic crisis. This research will need to determine which solutions are most effective and cost-effective in the context of particular countries and assess the risks and benefits of proposed solutions. Oceanographic and environmental research is needed to better measure concentrations and impacts of plastics <10 µm and understand their distribution and fate in the global environment. Biomedical research is needed to elucidate the human health impacts of plastics, especially MNPs. Summary: This Commission finds that plastics are both a boon to humanity and a stealth threat to human and planetary health. Plastics convey enormous benefits, but current linear patterns of plastic production, use, and disposal that pay little attention to sustainable design or safe materials and a near absence of recovery, reuse, and recycling are responsible for grave harms to health, widespread environmental damage, great economic costs, and deep societal injustices. These harms are rapidly worsening.While there remain gaps in knowledge about plastics' harms and uncertainties about their full magnitude, the evidence available today demonstrates unequivocally that these impacts are great and that they will increase in severity in the absence of urgent and effective intervention at global scale. Manufacture and use of essential plastics may continue. However, reckless increases in plastic production, and especially increases in the manufacture of an ever-increasing array of unnecessary single-use plastic products, need to be curbed.Global intervention against the plastic crisis is needed now because the costs of failure to act will be immense.


Assuntos
Doenças Cardiovasculares , Disruptores Endócrinos , Retardadores de Chama , Gases de Efeito Estufa , Neoplasias Pulmonares , Doença Pulmonar Obstrutiva Crônica , Estados Unidos , Criança , Animais , Humanos , Masculino , Feminino , Pré-Escolar , Plásticos/toxicidade , Plásticos/química , Ecossistema , Mônaco , Microplásticos , Poluentes Orgânicos Persistentes , Disruptores Endócrinos/toxicidade , Carvão Mineral
9.
J Am Chem Soc ; 133(41): 16386-9, 2011 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-21919507

RESUMO

Itaconic acid (ITA), or methylenesuccinic acid, is not generally classified as a mammalian metabolite. Using NMR-based metabolomics and (13)C-labeling, we have detected ITA in both macrophage-like VM-M3 and RAW 264.7 tumor cell lines as well as stimulated and unstimulated primary murine macrophages. Macrophage activation by addition of lipopolysaccharide and IFN-γ markedly increased ITA production and secretion. Crude cell extracts synthesize ITA via decarboxylation of cis-aconitate, indicative of a novel mammalian cis-aconitic decarboxylase activity. Our results highlight a previously unidentified biosynthetic pathway related to TCA cycle metabolism in mammalian cells and a novel metabolite that likely plays a role in macrophage-based immune response.


Assuntos
Macrófagos/metabolismo , Succinatos/metabolismo , Animais , Linhagem Celular Tumoral , Interferon gama/farmacologia , Lipopolissacarídeos/farmacologia , Macrófagos/efeitos dos fármacos , Camundongos , Succinatos/análise
10.
ACS Sens ; 4(3): 654-659, 2019 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-30773882

RESUMO

Rapid diagnosis of an infectious disease outbreak in the field is critical for limiting the escalation of an outbreak into an epidemic. Devices suited to point-of-care (POC) diagnosis of cholera must not only demonstrate clinical laboratory levels of sensitivity and specificity but do so in a portable and low-cost manner, with a simplistic readout. We report work toward an on-chip electrochemical immunosensor for the detection of cholera toxin subunit B (CTX), based on a dendritic gold architecture biofunctionalized via poly(2-cyanoethyl)pyrrole (PCEPy). The dendritic electrode has an ∼18× greater surface area than a planar gold counterpart, per electrochemical measurements, allowing for a higher level of detection sensitivity. A layer of PCEPy polymer generated on the dendritic surface facilitated the performance of an electrochemical enzyme-linked immunosorbant assay (ELISA) for CTX on-chip, which demonstrated a detection limit of 1 ng mL-1, per a signal-to-noise ratio of 2.6. This was more sensitive than detection using a simple planar gold electrode (100 ng mL-1) and also matched the diagnostic standard optical ELISA, but on a miniaturized platform with electrical readout. The ability to meet POC demands makes biofunctionalized gold dendrites a promising architecture for on-chip detection of cholera.


Assuntos
Dendrímeros/química , Eletroquímica/instrumentação , Ouro/química , Nanoestruturas/química , Polímeros/química , Pirróis/química , Toxina da Cólera/análise , Toxina da Cólera/química , Eletrodos , Limite de Detecção , Nanofios/química
11.
Sci Total Environ ; 650(Pt 2): 2389-2394, 2019 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-30292994

RESUMO

FINDINGS: The Lancet Commission on Pollution and Health found that pollution - air, water, soil, and chemical pollution - was responsible in 2016 for 940,000 deaths in children worldwide, two-thirds of them in children under the age of 5. Pollution is inequitably distributed, and the overwhelming majority of pollution-related deaths in children occurred in low- and middle-income countries (LMICs). Most were due to respiratory and gastrointestinal diseases caused by polluted air and water. Pollution is linked also to multiple non-communicable diseases (NCDs) in children including low birth weight, asthma, cancer and neurodevelopmental disorders, and these diseases are on the rise. The full impact of pollution, especially chemical pollution on the global burden of pediatric disease is not yet known, but almost certainly is undercounted because patterns of chemical exposure are not well charted and the potential toxicity of many chemical pollutants has not been characterized. The list of pediatric NCDs attributed to pollution will likely expand as the health effects of newer chemical pollutants are better defined and additional associations between pollution and disease are discovered. CONCLUSION: Pollution prevention presents a major, largely unexploited opportunity to improve children's health and prevent NCDs, especially in LMICs. Failure to incorporate pollution prevention into NCD control programs is a major missed opportunity for disease prevention.


Assuntos
Saúde da Criança , Exposição Ambiental/efeitos adversos , Poluição Ambiental/efeitos adversos
13.
J Am Chem Soc ; 130(24): 7746-55, 2008 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-18498165

RESUMO

D-3-deoxyphosphatidylinositol (D-3-deoxy-PI) derivatives have cytotoxic activity against various human cancer cell lines. These phosphatidylinositols have a potentially wide array of targets in the phosphatidylinositol-3-kinase (PI3K)/Akt signaling network. To explore the specificity of these types of molecules, we have synthesized D-3-deoxydioctanoylphosphatidylinositol (D-3-deoxy-diC8PI), D-3,5-dideoxy-diC8PI, and D-3-deoxy-diC8PI-5-phosphate and their enantiomers, characterized their aggregate formation by novel high-resolution field cycling (31)P NMR, and examined their susceptibility to phospholipase C (PLC), their effects on the catalytic activities of PI3K and PTEN against diC8PI and diC8PI-3-phosphate substrates, respectively, and their ability to induce the death of U937 human leukemic monocyte lymphoma cells. Of these molecules, only D-3-deoxy-diC8PI was able to promote cell death; it did so with a median inhibitory concentration of 40 microM, which is much less than the critical micelle concentration of 0.4 mM. Under these conditions, little inhibition of PI3K or PTEN was observed in assays of recombinant enzymes, although the complete series of deoxy-PI compounds did provide insights into ligand binding by PTEN. D-3-deoxy-diC8PI was a poor substrate and not an inhibitor of the PLC enzymes. The in vivo results are consistent with the current thought that the PI analogue acts on Akt1, since the transcription initiation factor eIF4e, which is a downstream signaling target of the PI3K/Akt pathway, exhibited reduced phosphorylation on Ser209. Phosphorylation of Akt1 on Ser473 but not Thr308 was reduced. Since the potent cytotoxicity for U937 cells was completely lost when L-3-deoxy-diC8PI was used as well as when the hydroxyl group at the inositol C5 in D-3-deoxy-diC8PI was modified (by either replacing this group with a hydrogen or phosphorylating it), both the chirality of the phosphatidylinositol moiety and the hydroxyl group at C5 are major determinants of the binding of 3-deoxy-PI to its target in cells.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Fosfatidilinositóis/química , Fosfatidilinositóis/farmacologia , Antineoplásicos/síntese química , Apoptose , Linhagem Celular Tumoral , Inibidores Enzimáticos/síntese química , Humanos , PTEN Fosfo-Hidrolase/antagonistas & inibidores , Inibidores de Fosfoinositídeo-3 Quinase , Relação Estrutura-Atividade , Fosfolipases Tipo C/química
14.
Mol Cancer ; 7: 37, 2008 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-18474106

RESUMO

BACKGROUND: AMP-activated protein kinase (AMPK) is a known physiological cellular energy sensor and becomes phosphorylated at Thr-172 in response to changes in cellular ATP levels. Activated AMPK acts as either an inducer or suppressor of apoptosis depending on the severity of energy stress and the presence or absence of certain functional tumor suppressor genes. RESULTS: Here we show that energy stress differentially affects AMPK phosphorylation and cell-death in brain tumor tissue and in tissue from contra-lateral normal brain. We compared TSC2 deficient CT-2A mouse astrocytoma cells with syngeneic normal astrocytes that were grown under identical condition in vitro. Energy stress induced by glucose withdrawal or addition of 2-deoxyglucose caused more ATP depletion, AMPK phosphorylation and apoptosis in CT-2A cells than in the normal astrocytes. Under normal energy conditions pharmacological stimulation of AMPK caused apoptosis in CT-2A cells but not in astrocytes. TSC2 siRNA treated astrocytes are hypersensitive to apoptosis induced by energy stress compared to control cells. AMPK phosphorylation and apoptosis were also greater in the CT-2A tumor tissue than in the normal brain tissue following implementation of dietary energy restriction. Inefficient mTOR and TSC2 signaling, downstream of AMPK, is responsible for CT-2A cell-death, while functional LKB1 may protect normal brain cells under energy stress. CONCLUSION: Together these data demonstrates that AMPK phosphorylation induces apoptosis in mouse astrocytoma but may protect normal brain cells from apoptosis under similar energy stress condition. Therefore, using activator of AMPK along with glycolysis inhibitor could be a potential therapeutic approach for TSC2 deficient human malignant astrocytoma.


Assuntos
Apoptose/fisiologia , Neoplasias Encefálicas/metabolismo , Encéfalo/metabolismo , Complexos Multienzimáticos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Quinases Ativadas por AMP , Aminoimidazol Carboxamida/análogos & derivados , Aminoimidazol Carboxamida/farmacologia , Animais , Apoptose/efeitos dos fármacos , Astrócitos/citologia , Astrócitos/enzimologia , Astrócitos/metabolismo , Astrocitoma/enzimologia , Astrocitoma/metabolismo , Astrocitoma/patologia , Western Blotting , Encéfalo/enzimologia , Encéfalo/patologia , Neoplasias Encefálicas/enzimologia , Neoplasias Encefálicas/patologia , Restrição Calórica , Linhagem Celular , Linhagem Celular Tumoral , Marcação In Situ das Extremidades Cortadas , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Fosforilação/efeitos dos fármacos , RNA Interferente Pequeno/genética , Ribonucleotídeos/farmacologia , Transfecção , Proteína 2 do Complexo Esclerose Tuberosa , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo
15.
Chem Biol ; 14(8): 923-30, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17719491

RESUMO

Oxidative stress is a deleterious force that must be combated relentlessly by aerobic organisms and is known to underlie many human diseases including atherosclerosis, Parkinson's disease, and Alzheimer's disease. Information available about the oxidative stress response has come primarily from studies using reactive oxygen species (ROS) with ill-defined locations within the cell. Thus, existing models do not account for possible differences between stress originating within particular regions of the cell. Here, oxidative stress is studied at the subcellular level using ROS-generating compounds localizing within two different organelles: the nucleus and the mitochondrion. Differences in cytotoxicity, gene expression, and survival pathway activation are detected as a function of the subcellular origin of oxidative stress, indicating that independent mechanisms are used to cope with oxidative stress arising in different cellular compartments. These comparative studies, enabled by the development of organelle-specific oxidants, examine the cellular responses to site-specific oxidative stress with heightened precision.


Assuntos
Organelas , Estresse Oxidativo , Peptídeos/metabolismo , Linhagem Celular , Citometria de Fluxo , Humanos , Reação em Cadeia da Polimerase , Espécies Reativas de Oxigênio/metabolismo
16.
Environ Health Perspect ; 126(8): 084501, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30118434

RESUMO

SUMMARY: Pollution is a major, overlooked, global health threat that was responsible in 2015 for an estimated 9 million deaths and great economic losses. To end neglect of pollution and advance prevention of pollution-related disease, we formed the Lancet Commission on Pollution and Health. Despite recent gains in understanding of pollution and its health effects, this Commission noted that large gaps in knowledge remain. To close these gaps and guide prevention, the Commission made research recommendations and proposed creation of a Global Observatory on Pollution and Health. We posit that successful pollution research will be translational and based on transdisciplinary collaborations among exposure science, epidemiology, data science, engineering, health policy, and economics. We envision that the Global Observatory on Pollution and Health will be a multinational consortium based at Boston College and the Harvard T.H. Chan School of Public Health that will aggregate, geocode, and archive data on pollution and pollution-related disease; analyze these data to discern trends, geographic patterns, and opportunities for intervention; and make its findings available to policymakers, the media, and the global public to catalyze research, inform policy, and assist cities and countries to target pollution, track progress, and save lives. https://doi.org/10.1289/EHP3141.


Assuntos
Poluição Ambiental/prevenção & controle , Saúde Global , Política de Saúde , Boston
17.
Biofactors ; 30(4): 271-7, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-18607077

RESUMO

Carbon nanotube and metal particle composites have been exploited to fabricate high performance electrochemical devices. However, the physical and chemical procedures to synthesize the composites are labor intensive and inefficient. Our study reveals an one-step wet chemistry method to accomplish fast and controllable production of gold nanoparticle (AuNP) and carbon naotube (CNT) composites. Such a process is sensitive to the surface charge. Especially, when functionalized with carboxyl groups, the CNTs carried negative charges and showed low level association with negatively charged AuNPs. Thermal treatment was employed to decompose the carboxyl groups and render each CNT a charge-free surface thereby achieving a high level AuNP-CNT association. The fabricated glucose sensors demonstrated dependence of their sensitivities to the amount of AuNPs on the CNTs. The enhancement of sensitivity can be attributed to an accelerated electron transfer rate from glucose oxidase Gox to the electrode. The Michaelis-Menten kinetics also indicated improved performance in the glucose sensor made of AuNP-CNTs. Therefore, our research revealed a novel approach to produce metallic nanoparticle and CNT composite for fabricating high performance electrochemical sensors.


Assuntos
Técnicas Biossensoriais/instrumentação , Glucose/análise , Ouro/química , Nanopartículas Metálicas , Nanotubos de Carbono , Técnicas Biossensoriais/métodos , Eletroquímica , Glucose Oxidase/metabolismo , Microscopia Eletrônica de Transmissão
18.
Biochem Pharmacol ; 72(10): 1246-56, 2006 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-16979140

RESUMO

An abnormally high rate of aerobic glycolysis is characteristic of many transformed cells. Here we report the polyphenolic compound, resveratrol, inhibited phosphatidylinositol 3-kinase (PI-3K) signaling and glucose metabolism, coinciding with cell-cycle arrest, in germinal center (GC)-like LY1 and LY18 human diffuse large B-cell lymphomas (DLBCLs). Specifically, resveratrol inhibited the phosphorylation of Akt, p70 S6K, and S6 ribosomal protein on activation residues. Biochemical analyses and nuclear magnetic resonance spectroscopy identified glycolysis as the primary glucose catabolic pathway in LY18 cells. Treatment with the glycolytic inhibitor 2-deoxy-D-glucose, resulted in accumulation of LY18 cells in G0/G1 -phase, underscoring the biological significance of glycolysis in growth. Glycolytic flux was inhibited by the PI-3K inhibitor LY294002, suggesting a requirement for PI-3K activity in glucose catabolism. Importantly, resveratrol treatment resulted in inhibition of glycolysis. Decreased glycolytic flux corresponded to a parallel reduction in the expression of several mRNAs encoding rate-limiting glycolytic enzymes. These results are the first to identify as a mechanism underlying resveratrol-induced growth arrest, the inhibition of glucose catabolism by the glycolytic pathway. Taken together, these results raise the possibility that inhibition of signaling and metabolic pathways that control glycolysis might be effective in therapy of DLBCLs.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Ciclo Celular/efeitos dos fármacos , Glucose/metabolismo , Glicólise/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Estilbenos/farmacologia , Linhagem Celular Tumoral , Cromonas/farmacologia , Inibidores Enzimáticos/farmacologia , Humanos , Linfoma Difuso de Grandes Células B/patologia , Morfolinas/farmacologia , Inibidores de Fosfoinositídeo-3 Quinase , Resveratrol
19.
Int J Oncol ; 29(6): 1561-6, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17088997

RESUMO

Resveratrol is a polyphenolic compound that exhibits anti-proliferative and anti-inflammatory activities. BCL6, a transcriptional repressor frequently translocated in lymphomas, including diffuse large B-cell lymphoma (DLBCL) and transformed follicular lymphoma (FL), regulates germinal center B-cell differentiation. We report herein that resveratrol treatment of human LY8 follicular lymphoma cells leads to an accumulation of LY8 cell in G0/G1 phase and apoptosis. Resveratrol decreased the expression of BCL6 protein, concomitant with the increased expression of several BCL6 regulated gene products, including p27, p53 and CD69. In addition, resveratrol reduces Myc expression in LY8 cells. These results demonstrate for the first time that resveratrol inhibits a BCL6-linked pathway and suggest that loss of BCL6 expression may represent a key event underlying the anti-proliferative activities of resveratrol on LY8 cells. The use of resveratrol to treat aggressive lymphomas with BCL6 and/or MYC translocations may prove useful as an effective therapy.


Assuntos
Apoptose/efeitos dos fármacos , Proteínas de Ligação a DNA/antagonistas & inibidores , Linfoma de Células B/tratamento farmacológico , Linfoma Folicular/tratamento farmacológico , Estilbenos/farmacologia , Antineoplásicos Fitogênicos/farmacologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Transformada , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Genes myc/efeitos dos fármacos , Genes p53/efeitos dos fármacos , Humanos , Linfoma de Células B/genética , Linfoma de Células B/metabolismo , Linfoma de Células B/patologia , Linfoma Folicular/genética , Linfoma Folicular/metabolismo , Linfoma Folicular/patologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Antígeno Nuclear de Célula em Proliferação/genética , Proteínas Proto-Oncogênicas c-bcl-6 , Resveratrol
20.
J Vis Exp ; (109)2016 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-27023367

RESUMO

RNA interference (RNAi), a naturally occurring phenomenon in eukaryotic organisms, is an extremely valuable tool that can be utilized in the laboratory for functional genomic studies. The ability to knockdown individual genes selectively via this reverse genetic technique has allowed many researchers to rapidly uncover the biological roles of numerous genes within many organisms, by evaluation of loss-of-function phenotypes. In the major human malaria vector Anopheles gambiae, the predominant method used to reduce the function of targeted genes involves injection of double-stranded (dsRNA) into the hemocoel of the adult mosquito. While this method has been successful, gene knockdown in adults excludes the functional assessment of genes that are expressed and potentially play roles during pre-adult stages, as well as genes that are expressed in limited numbers of cells in adult mosquitoes. We describe a method for the injection of Serine Protease Inhibitor 2 (SRPN2) dsRNA during the early pupal stage and validate SRPN2 protein knockdown by observing decreased target protein levels and the formation of melanotic pseudo-tumors in SRPN2 knockdown adult mosquitoes. This evident phenotype has been described previously for adult stage knockdown of SRPN2 function, and we have recapitulated this adult phenotype by SRPN2 knockdown initiated during pupal development. When used in conjunction with a dye-labeled dsRNA solution, this technique enables easy visualization by simple light microscopy of injection quality and distribution of dsRNA in the hemocoel.


Assuntos
Anopheles/genética , Técnicas de Transferência de Genes , Pupa/genética , Interferência de RNA/fisiologia , Animais , Feminino , Técnicas Genéticas , Malária , Masculino , Fenótipo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA