RESUMO
Chronic inflammatory disorders are associated with biomolecular damage attributed partly to reactions with Reactive Oxygen Species (ROS), particularly hydroxyl radicals (â¢OH). However, the impacts of serum electrolytes on ROS-associated damage has received little attention. We demonstrate that the conversion of â¢OH to carbonate and halogen radicals via reactions with serum-relevant carbonate and halide concentrations fundamentally alters the targeting of amino acids and loss of enzymatic activity in catalase, albumin and carbonic anhydrase, three important blood proteins. Chemical kinetic modeling indicated that carbonate and halogen radical concentrations should exceed â¢OH concentrations by 6 and 2 orders of magnitude, respectively. Steady-state γ-radiolysis experiments demonstrated that serum-level carbonates and halides increased tyrosine, tryptophan and enzymatic activity losses in catalase up to 6-fold. These outcomes were specific to carbonates and halides, not general ionic strength effects. Serum carbonates and halides increased the degradation of tyrosines and methionines in albumin, and increased the degradation of histidines while decreasing enzymatic activity loss in carbonic anhydrase. Serum electrolytes increased the degradation of tyrosines, tryptophans and enzymatic activity in the model enzyme, ketosteroid isomerase, predominantly due to carbonate radical reactions. Treatment of a mutant ketosteroid isomerase indicated that preferential targeting of the active site tyrosine accounted for half of the total tyrosine loss. The results suggest that carbonate and halogen radicals may be more significant than â¢OH as drivers for protein degradation in serum. Accounting for the selective targeting of biomolecules by these daughter radicals is important for developing a mechanistic understanding of the consequences of oxidative stress.
Assuntos
Eletrólitos/toxicidade , Radicais Livres/toxicidade , Radical Hidroxila/toxicidade , Inflamação/sangue , Carbonatos/toxicidade , Catalase/genética , Halogênios/toxicidade , Humanos , Inflamação/induzido quimicamente , Inflamação/genética , Inflamação/patologia , Cinética , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Proteólise/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Poluentes Químicos da ÁguaRESUMO
BACKGROUND: Storage of donor hearts in cardioplegic solutions supplemented with conditioning agents activating endogenous mitochondrial protective signaling enhanced their postreperfusion recovery. The present study investigates the role of timing and duration of cardiac exposure to cyclosporine A (CsA), another putative mitochondrial protectant, on cardiac functional recovery and potential mechanisms of CsA action in an isolated working rat heart model of donor heart retrieval and storage. METHODS: After measurement of baseline function, hearts were arrested and stored for 6 hours at 4°C in either Celsior alone or Celsior + CsA (0.2 µM), then reperfused for 45 minutes in Krebs solution, when functional recovery was assessed. Two additional groups of Celsior-alone stored hearts were exposed to 0.2 µM CsA for the initial 15 minutes (nonworking period) or the full 45-minute period of reperfusion. Coronary effluent was collected pre- and poststorage for assessment of lactate dehydrogenase release. Tissue samples were collected at the end of each study for immunoblotting and histological studies. RESULTS: CsA supplementation during cold storage or the first 15-minute reperfusion significantly improved functional recovery and significantly increased phospho-AMPKαThr172 and phospho-ULK-1Ser757. Hearts exposed to CsA for 45 minutes at reperfusion recovered poorly with no phospho-AMP-activated protein kinase α activation, decreased phospho-eNOSSer633, and decreased mitochondrial cytochrome c content with increased lactate dehydrogenase release. CONCLUSIONS: Inclusion of CsA during cold storage is cardioprotective. Effects of CsA addition to the perfusate during reperfusion were time dependent, with benefits at 15 minutes but not 45 minutes of reperfusion. The toxic effect with the presence of CsA for the full 45-minute reperfusion is associated with impaired mitochondrial integrity and decreased eNOS phosphorylation.
Assuntos
Soluções Cardioplégicas/farmacologia , Ciclosporina/farmacologia , Transplante de Coração , Coração/efeitos dos fármacos , Soluções para Preservação de Órgãos/farmacologia , Preservação de Órgãos , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/metabolismo , Soluções Cardioplégicas/toxicidade , Isquemia Fria , Ciclosporina/toxicidade , Dissacarídeos/farmacologia , Dissacarídeos/toxicidade , Eletrólitos/farmacologia , Eletrólitos/toxicidade , Glutamatos/farmacologia , Glutamatos/toxicidade , Glutationa/farmacologia , Glutationa/toxicidade , Coração/fisiopatologia , Transplante de Coração/efeitos adversos , Histidina/farmacologia , Histidina/toxicidade , Preparação de Coração Isolado , Masculino , Manitol/farmacologia , Manitol/toxicidade , Mitocôndrias Cardíacas/efeitos dos fármacos , Mitocôndrias Cardíacas/metabolismo , Mitocôndrias Cardíacas/patologia , Óxido Nítrico Sintase Tipo III/metabolismo , Soluções para Preservação de Órgãos/toxicidade , Fosforilação , Ratos Wistar , Recuperação de Função Fisiológica , Fatores de TempoRESUMO
Existing neuroanatomical models argue that the bed nucleus of the stria terminalis (BST) principally mediates sustained, long-lasting fear or anxiety responses, but not shorter, phasic fear responses, although recent studies paint a more complex picture. In the current study, we evaluated the effect of post-training electrolytic BST lesions in a cued fear conditioning protocol with relatively short (10 s) tones. We hypothesized that the BST would not play a crucial role in the expression of fear upon re-exposure to the conditioned tones. Tone fear memory was primarily assessed through fear-potentiated startle. In addition, freezing measurements were obtained throughout the test sessions. In a series of three experiments, we explored the effects of BST lesions, taking into consideration contextual influences on cued fear expression (using (dis)similar training and test contexts) and temporal involvement of the BST in the consolidation of fear learning (lesion induction 3 or 27 h after fear conditioning). In all three experiments, we found that post-training electrolytic lesions of the BST significantly reduced fear-potentiated startle, implying a deficit in differentiation between tone and context. These results are surprising and challenge the general consensus on the lack of BST involvement in cued fear. We discuss several alternative explanations that may account for these unexpected findings.
Assuntos
Condicionamento Clássico/fisiologia , Sinais (Psicologia) , Medo , Reflexo de Sobressalto/fisiologia , Núcleos Septais/lesões , Núcleos Septais/fisiologia , Estimulação Acústica , Animais , Eletrólitos/toxicidade , Reação de Congelamento Cataléptica/fisiologia , Masculino , Ratos , Ratos Wistar , Estatísticas não Paramétricas , Fatores de TempoRESUMO
A novel method based on liquid-liquid extraction with subsequent gas chromatography separation and mass spectrometric detection (GC-MS) for the quantification of organic carbonates in cell culture materials is presented. Method parameters including the choice of extraction solvent, of extraction method and of extraction time were optimised and the method was validated. The setup allowed for determination within a linear range of more than two orders of magnitude. The limits of detection (LODs) were between 0.0002 and 0.002 mmol/L and the repeatability precisions were in the range of 1.5-12.9%. It could be shown that no matrix effects were present and recovery rates between 98 and 104% were achieved. The methodology was applied to cell culture models incubated with commercial lithium ion battery (LIB) electrolytes to gain more insight into the potential toxic effects of these compounds. The stability of the organic carbonates in cell culture medium after incubation was studied. In a porcine model of the blood-cerebrospinal fluid (CSF) barrier, it could be shown that a transfer of organic carbonates into the brain facing compartment took place. Graphical abstract Schematic setup for the investigation of toxicity of lithium ion battery electrolytes.
Assuntos
Dioxolanos/análise , Dioxóis/análise , Fontes de Energia Elétrica/efeitos adversos , Formiatos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Extração Líquido-Líquido/métodos , Animais , Disponibilidade Biológica , Técnicas de Cultura de Células/métodos , Linhagem Celular Tumoral , Meios de Cultura/análise , Dioxolanos/farmacocinética , Dioxóis/farmacocinética , Eletrólitos/toxicidade , Formiatos/farmacocinética , Humanos , Limite de Detecção , Lítio/toxicidade , Suínos , Testes de Toxicidade/métodosRESUMO
Over the last few years, considerable efforts are taken, in order to find a molecular fluorescent probe fulfilling their applicability requirements. Due to a good optical properties and affinity to biological structures conjugated oligoelectrolytes (COEs) can be considered as a promising dyes for application in fluorescence-based bioimaging. In this work, we synthetized COEs with phenylenevinylene core (PV-COEs) and applied as fluorescent membranous-specific probes. Cytotoxicity effects of each COE were probed on cancerous and non-cancerous cell types and little to no toxicity effects were observed at the high range of concentrations. The intensity of cell fluorescence following the COE staining was determined by the photoluminescence analysis and fluorescence activated cell sorting method (FACS). Intercalation of tested COEs into mammalian cell membranes was revealed by fluorescent and confocal microscopy colocalization with commercial dyes specific for cellular structures including mitochondria, Golgi apparatus and endoplasmic reticulum. The phenylenevinylene conjugated oligoelectrolytes have been found to be suitable for fluorescent bioimaging of mammalian cells and membrane-rich organelles. Due to their water solubility coupled with spontaneous intercalation into cells, favorable photophysical features, ease of cell staining, low cytotoxicity and selectivity for membranous structures, PV-COEs can be applied as markers for fluorescence imaging of a variety of cell types.
Assuntos
Eletrólitos/química , Corantes Fluorescentes/química , Microscopia Confocal , Animais , Células 3T3 BALB , Linhagem Celular , Membrana Celular/química , Membrana Celular/metabolismo , Sobrevivência Celular , Eletrólitos/toxicidade , Citometria de Fluxo , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Substâncias Intercalantes/química , Células K562 , CamundongosRESUMO
Each year, the United States spends about $20 billion to treat people who have been infected with antibiotic resistant bacteria. Even so, the development of new antibiotics has slowed considerably since the mid-20th century. As a result, researchers are looking into developing synthetic compounds and materials with antimicrobial activities such as those made by the Schanze and Whitten groups [ACS Appl. Mater. Interfaces 3, 2820 (2011)]. Previously, they have demonstrated that poly(phenylene ethynylene) (PPE) based electrolytes and oligomeric end-only phenylene ethynylene (EO-OPE) based electrolytes possess strong biocidal activity. However, before the PPE and OPE can be used with humans, skin irritation tests are required to ensure their safety. In this work, in vitro skin assays are used to predict in vivo irritation. Tissues were conditioned for 24 h, exposed to test substances for 1 h, and then tested for viability using colorimetric and cytokine assays. Concentrations up to 50 µg/ml were tested. Viability assays and cytokine (IL-1α) assays demonstrated that the two polymers, three symmetric oligomers, and three "end only" oligomers were nonirritants. In addition, electrospun mats consisting of several promising compounds, including poly(caprolactone), were evaluated. Therefore, all test substances are conservatively classified as nonirritants after a 1 h exposure time period.
Assuntos
Alcinos/química , Anti-Infecciosos/química , Eletrólitos/química , Éteres/química , Alcinos/toxicidade , Técnicas de Cultura de Células , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Eletrólitos/toxicidade , Ensaio de Imunoadsorção Enzimática , Éteres/toxicidade , Humanos , Interleucina-1alfa/análise , Queratinócitos/citologia , Queratinócitos/efeitos dos fármacos , Queratinócitos/metabolismoRESUMO
The interaction between polymers and biological membranes has recently gained significant interest in several research areas. On the biomedical side, dendrimers, linear polyelectrolytes, and neutral copolymers find application as drug and gene delivery agents, as biocidal agents, and as platforms for biological sensors. On the environmental side, plastic debris is often disposed of in the oceans and gets degraded into small particles; therefore concern is raising about the interaction of small plastic particles with living organisms. From both perspectives, it is crucial to understand the processes driving the interaction between polymers and cell membranes. In recent times progress in computer technology and simulation methods has allowed computational predictions on the molecular mechanism of interaction between polymeric materials and lipid membranes. Here we review the computational studies on the interaction between lipid membranes and different classes of polymers: dendrimers, linear charged polymers, polyethylene glycol (PEG) and its derivatives, polystyrene, and some generic models of polymer chains. We conclude by discussing some of the technical challenges in this area and future developments.
Assuntos
Lipídeos de Membrana/química , Modelos Biológicos , Nanopartículas/química , Nanopartículas/toxicidade , Polímeros/química , Polímeros/toxicidade , Fenômenos Biofísicos , Simulação por Computador , Dendrímeros/química , Dendrímeros/toxicidade , Eletrólitos/química , Eletrólitos/toxicidade , Modelos Químicos , Simulação de Dinâmica Molecular , Polietilenoglicóis/química , Polietilenoglicóis/toxicidade , Poliestirenos/química , Poliestirenos/toxicidadeRESUMO
Understanding the inherent toxicity of water-soluble synthetic polyelectrolytes is critical for adequate risk management as well as enhancing product design when biological activity is a key performance index (e.g. for application in biofouling bivalves' control). The toxicity of two cationic acrylamide copolymers with different chain branching degree was evaluated. Standard ecotoxicity tests were conducted with microalgae and daphnids. The susceptibility of Corbicula fluminea, as a biofouling bivalve, was also evaluated. The effect of polyelectrolyte on the test media viscosity and the polymer chain size distributions under the experimental conditions were also examined. The susceptibility of the microalgae to both polymers was similar. As the complexity and size of the test organisms increased, differences in toxicity due to different chain architecture were noticeable. The more branched polymer was significantly less toxic to both daphnids and the bivalves, which could be linked to the distinctive features of its bimodal size chain distribution. This architecture resulted in both more compact globular molecules and the formation of aggregates, which reduce the polymer interaction with the biological surfaces. The results of this study promote the incorporation of environmental considerations in polyelectrolyte development and contribute to the design of improved solutions for controlling biofouling bivalves.
Assuntos
Acrilamida/química , Acrilamida/toxicidade , Organismos Aquáticos/efeitos dos fármacos , Ecotoxicologia , Poluentes Químicos da Água/química , Poluentes Químicos da Água/toxicidade , Animais , Incrustação Biológica/prevenção & controle , Corbicula/efeitos dos fármacos , Eletrólitos/química , Eletrólitos/toxicidade , Polímeros/química , Polímeros/toxicidade , Medição de Risco , Solubilidade , Relação Estrutura-Atividade , Água/químicaRESUMO
The layer-by-layer technique, which allows simple preparation of polyelectrolyte multilayers, came into the focus of research for development of functionalized medical devices. Numerous literature exist that concentrate on the film build-up and the behaviour of cells on polyelectrolyte multilayers. However, in case of very soft polyelectrolyte multilayers, studies of the cell behaviour on these films are sometimes misleading with regard to clinical applications because cells do not die due to cytotoxicity but due to apoptosis by missing cell adhesion. It turns out that the adhesion in vitro, and thus, the viability of cells on polyelectrolyte multilayers is mostly influenced by their mechanical properties. In order to decide, which polyelectrolyte multilayers are suitable for implants, we take this problem into account by putting the substrates with soft films on top of pre-cultured human primary endothelial cells ('reverse assay'). Hence, the present work aims giving a more complete and reliable study of typical polyelectrolyte multilayers with regard to clinical applications. In particular, coatings consisting of hyaluronic acid and chitosan as natural polymers and sulfonated polystyrene and polyallylamine hydrochlorite as synthetic polymers were studied. The adsorption of polyelectrolytes was characterized by physico-chemical methods which show regular buildup. Biological examination of the native or modified polyelectrolyte multilayers was based on their effect to cell adhesion and morphology of endothelial cells by viability assays, immunostaining and scanning electron microscopy. Using the standard method, which is typically applied in literature--seeding cells on top of films--shows that the best adhesion and thus, viability can be achieved using sulfonated polystyrene/polyallylamine hydrochlorite. However, putting the films on top of endothelial cells reveals that hyaluronic acid/chitosan may also be suitable for clinical applications: This result is especially remarkable, since hyaluronic acid and chitosan mediate per se no cytotoxic effects, whereas the individual polyelectrolytes, sulfonated polystyrene and polyallylamine hydrochlorite, and their complexes show slight cytotoxicity.
Assuntos
Materiais Biocompatíveis/química , Eletrólitos/química , Polímeros/química , Materiais Biocompatíveis/toxicidade , Adesão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Quitosana/química , Quitosana/toxicidade , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/toxicidade , Eletrólitos/toxicidade , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/fisiologia , Humanos , Ácido Hialurônico/química , Ácido Hialurônico/toxicidade , Teste de Materiais , Potenciais da Membrana/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Poliaminas/química , Poliaminas/toxicidade , Polímeros/toxicidade , Poliestirenos/química , Poliestirenos/toxicidade , Técnicas de Microbalança de Cristal de Quartzo , Propriedades de SuperfícieRESUMO
Foot pad dermatitis (FPD) is a very common disease affecting poultry and is mostly caused by bad litter condition. This study aimed to test the effects of poultry diets with normal levels of electrolytes compared with a surplus level of electrolytes with and without using floor heating. Eighty two-week-old â turkey poults were reared over 3 weeks on wood shavings, divided randomly into four groups. Two groups were fed normal levels of electrolytes (1.60 g Na; 7.80 g K/kg diet), and the other two groups were fed surplus levels of electrolytes (3.10; 15.3 g/kg diet). In each dietary treatment, half of the birds were exposed to floor heating. Half of the birds in each group were exposed for 4 h/day to wet litter (35% water) in adjacent separate boxes. External assessment of foot pads was performed weekly. High dietary electrolytes increased the severity of FPD significantly (3.65 ± 1.03). Floor heating is likely to be highly effective in significantly reducing the severity of FPD (2.36 ± 0.588). Despite forced water intake, the litter became drier when floor heating was in use. Combining low Na and K levels with a floor heating system reduced the scores of FPD by approximately 60%, compared with high electrolyte levels without floor heating. Therefore, both dietary electrolyte levels and floor heating markedly affected FPD via litter moisture.
Assuntos
Ração Animal/análise , Dermatite/veterinária , Eletrólitos/toxicidade , Doenças do Pé/veterinária , Doenças das Aves Domésticas/etiologia , Perus , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dermatite/etiologia , Dermatite/patologia , Dermatite/prevenção & controle , Dieta/veterinária , Eletrólitos/química , Feminino , Pisos e Cobertura de Pisos , Doenças do Pé/etiologia , Doenças do Pé/patologia , Doenças do Pé/prevenção & controle , Calefação , Abrigo para Animais , Doenças das Aves Domésticas/patologia , Doenças das Aves Domésticas/prevenção & controleRESUMO
Flocculant blocks are commonly used as a component of (passive) water treatment systems to reduce suspended sediment loads in the water column. This study investigated the potential for aquatic biological impacts of a flocculant block formulation that contained an anionic polyacrylamide (PAM) active ingredient and a polyethylene glycol (PEG) based carrier. The toxicity of the whole flocculant block was assessed and the individual components of the block were also tested separately. Five Northern Australian tropical freshwater species (i.e. Chlorella sp. Lemna aequinoctialis, Hydra viridissima, Moinodaphnia macleayi and Mogurnda mogurnda) were exposed to a range of concentrations of the whole flocculant block, and of the individual PAM and PEG components. The concentration of Total Organic Carbon (TOC) in solution was used to provide a measure of the total amount of PAM and PEG present. An extremely wide range of toxic responses were found, with the flocculant blocks being essentially non-toxic to the duckweed, fish and algae (IC(50)>1880mgl(-1)CTOC, IC(10)>460mgl(-1)CTOC), slightly toxic to the hydra (IC(50)=610-2180mgl(-1)CTOC, IC(10)=80-60mgl(-1)CTOC) and significantly more toxic to the cladoceran (IC(50)=10mgl(-1)CTOC, IC(10)=4mgl(-1)CTOC). More detailed investigation of the two components indicated that the PAM was the primary "toxicant" in the flocculant blocks. Derived Protective Concentrations (PCs) for the flocculant blocks, expressed as equivalent TOC concentrations, were found to be lower than typically measured natural environmental concentrations of TOC. It will thus be possible to use TOC as measure of the concentration of PAM only in those situations where lower levels of ecosystem protection (i.e. higher PCs) are applicable.
Assuntos
Ecotoxicologia/métodos , Eletrólitos/toxicidade , Plantas/efeitos dos fármacos , Resinas Acrílicas/toxicidade , Austrália , Carbono/análise , Monitoramento Ambiental , Floculação/efeitos dos fármacos , Água Doce , Compostos Orgânicos/análise , Polietilenoglicóis/toxicidade , Testes de ToxicidadeRESUMO
Layer-by-layer assembly of polyelectrolyte multilayer (PEM) films represents a bottom-up approach for re-engineering the molecular landscape of cell surfaces with spatially continuous and molecularly uniform ultrathin films. However, fabricating PEMs on viable cells has proven challenging owing to the high cytotoxicity of polycations. Here, we report the rational engineering of a new class of PEMs with modular biological functionality and tunable physicochemical properties which have been engineered to abrogate cytotoxicity. Specifically, we have discovered a subset of cationic copolymers that undergoes a conformational change, which mitigates membrane disruption and facilitates the deposition of PEMs on cell surfaces that are tailorable in composition, reactivity, thickness, and mechanical properties. Furthermore, we demonstrate the first successful in vivo application of PEM-engineered cells, which maintained viability and function upon transplantation and were used as carriers for in vivo delivery of PEMs containing biomolecular payloads. This new class of polymeric film and the design strategies developed herein establish an enabling technology for cell transplantation and other therapies based on engineered cells.
Assuntos
Materiais Biocompatíveis/química , Bioengenharia , Membrana Celular/química , Transplante das Ilhotas Pancreáticas , Polímeros/química , Animais , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/toxicidade , Eletrólitos/síntese química , Eletrólitos/química , Eletrólitos/toxicidade , Ilhotas Pancreáticas/química , Camundongos , Poliaminas/síntese química , Poliaminas/química , Poliaminas/toxicidade , Polieletrólitos , Polietilenoglicóis/síntese química , Polietilenoglicóis/química , Polietilenoglicóis/toxicidade , Polilisina/análogos & derivados , Polilisina/síntese química , Polilisina/química , Polilisina/toxicidade , Polímeros/síntese química , Polímeros/toxicidadeRESUMO
Hydrogen-dissolved water has been suggested to be effective for alleviating the oxidative stress. In the present study, neutral-pH hydrogen-enriched electrolyzed water (NHE-water; dissolved hydrogen: 0.90-1.14 parts per million [ppm]; oxido-reduced potential: -150 approximately -80 mV), which was prepared with a water-electrolysis apparatus equipped with a non-diaphragm cell and a highly compressed activated-carbon block, was evaluated for the mutagenic and genotoxic potentials, at concentrations up to 100% dose/plate, and for the subchronic toxicity. NHE-water did not induce reverse mutations in Salmonella typhimurium strains TA100, TA1535, TA98 and TA1537, and Escherichia coli strain WP2uvrA, in either the absence or presence of rat liver S9 for exogenous metabolic activation. Similarly, NHE-water did not induce chromosome aberrations in Chinese hamster lung fibroblast cells (CHL/IU), in short-term (6-hour) tests, with or without rat liver S9, or in a continuous treatment (24-hour) test. To evaluate the subchronic toxicity, Crj:CD(SD) specific pathogen free (SPF)-rats were administered with NHE-water at a dose of 20 mL/kg/day for 28 days via intragastric infusion. NHE-water-related toxic changes were not seen in terms of any items such as clinical symptoms, body weight, food consumption, urinalysis, hematology, blood chemistry, necropsy, each organ weight and histopathology. Thus, the no-observable-adverse-effect level (NOAEL) for NHE-water was estimated to be greater than 20 mL/kg/day under the conditions examined, demonstrating the consistency with the expected safety for a human with a body weight of 60 kg to drink the NHE-water up to at least 1.2 L/day.
Assuntos
Eletrólitos/toxicidade , Administração Oral , Animais , Linhagem Celular , Aberrações Cromossômicas/efeitos dos fármacos , Cricetinae , Cricetulus , Dano ao DNA , Relação Dose-Resposta a Droga , Eletrólitos/administração & dosagem , Escherichia coli/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Testes de Mutagenicidade , Nível de Efeito Adverso não Observado , Estresse Oxidativo/efeitos dos fármacos , Ratos , Salmonella typhimurium/efeitos dos fármacos , ÁguaRESUMO
Living cells encapsulated in polymeric shells are receiving increasing attention because of their possible biotechnological and biomedical applications. The aim of this work is to evaluate how different polyelectrolyte coatings, characterized by different numbers of polyelectrolyte layers and by different polyelectrolyte conformations, affect the viability of encapsulated biological material. We demonstrate the ability to individually encapsulate HL-60 cells as well as rat pancreatic islets within polymeric shells consisting of different PE layers using the layer-by-layer process. Coating of HL-60 cells allows for surviving and functioning of cells for all applied PE as well as for different numbers of layers. The islets encapsulated in applied polyelectrolytes exhibited the lower level of mitochondrial activity as compared to non-encapsulated islets. Nevertheless, encapsulated islets exhibited comparable absorbance values during the whole period of culture. Polyelectrolyte coating seems to be a promising way of allowing capsule void volume minimization in a model of encapsulated biological material for local production of biologically active substances.
Assuntos
Células/metabolismo , Eletrólitos/química , Eletrólitos/metabolismo , Polímeros/química , Polímeros/metabolismo , Animais , Sobrevivência Celular/efeitos dos fármacos , Células/citologia , Células/efeitos dos fármacos , Eletrólitos/toxicidade , Células HL-60 , Humanos , Ilhotas Pancreáticas/citologia , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Células Jurkat , Microscopia de Força Atômica , Conformação Molecular , Nanocápsulas/química , Polímeros/toxicidade , RatosRESUMO
The toxicity of 11 polyquaterniums used in cosmetic applications, and polydimethyldiallylammonium chloride (poly(DADMAC)) were studied for toxicity of the polyquaternium alone, and of a polyquaternium/anionic surfactant complex as occurs in some cosmetic formulations. The surfactant used in the study was sodium dodecyl sulfate (SDS), which is used in cosmetic formulations under its International Nomenclature of Cosmetic Ingredients (INCI) name Sodium Laurel Sulfate. In fish immobilization studies with Gambusia holbrooki, the EC(50) of the polyquaternium/surfactant complex was found to be the same as or similar to the EC(50) for the polyquaternium alone. The toxicity of the polyquaterniums investigated was similar to the published values for other cationic polyelectrolytes and cationic surfactants, in the range from < 1.0 to 10 mg/L, with the exception of low charge density cellulosic polyquaterniums. The anionic surfactant alone was not toxic to fish in the concentration range tested. Results thus showed the toxicity of the polyquaternium was not mitigated by the presence of the anionic surfactant.
Assuntos
Ciprinodontiformes/crescimento & desenvolvimento , Ecotoxicologia , Eletrólitos/toxicidade , Polímeros/toxicidade , Compostos de Amônio Quaternário/toxicidade , Tensoativos/toxicidade , Animais , Cosméticos/química , Cosméticos/toxicidade , Dodecilsulfato de Sódio/toxicidadeRESUMO
Organ preservation solutions have been designed to protect grafts against the injury inflicted by cold ischemia. However, toxicity of University of Wisconsin (UW) solution during rewarming has been reported. Therefore, we here assessed the toxicity of UW, histidine-tryptophan-ketoglutarate (HTK), Euro-Collins, histidine-lactobionate (HL), sodium-lactobionate-sucrose and Celsior solutions in cultured hepatocytes under hypothermic (4 degrees C), intermediate (21 degrees C) and physiological (37 degrees C) conditions. Marked toxicity of UW, HTK, HL and Euro-Collins solutions was observed at both 37 and 21 degrees C. With the exception of UW solution, these solutions also increased cell injury during cold incubation (LDH release after 18 h at 4 degrees C: HTK 76+/-2%, Euro-Collins 78+/-17%, HL 81+/-15%; control: Krebs-Henseleit buffer 20+/-6%). Testing of individual components using modified Krebs-Henseleit buffers suggested that histidine and phosphate are responsible for (part of) this toxicity. These potential toxicities should be taken into account in the development of future preservation solutions.
Assuntos
Hepatócitos/efeitos dos fármacos , Soluções para Preservação de Órgãos/toxicidade , Adenosina/toxicidade , Alopurinol/toxicidade , Animais , Células Cultivadas , Temperatura Baixa , Dissacarídeos/toxicidade , Eletrólitos/toxicidade , Glucose/toxicidade , Glutamatos/toxicidade , Glutationa/toxicidade , Histidina/toxicidade , Soluções Hipertônicas/toxicidade , Insulina/toxicidade , Masculino , Manitol/toxicidade , Cloreto de Potássio/toxicidade , Procaína/toxicidade , Rafinose/toxicidade , Ratos , Ratos Wistar , Sacarose/toxicidadeRESUMO
The use of polymers in the production of drinking water is reviewed, with emphasis on the nature of the impurities to be removed, the mechanisms of coagulation and flocculation, and the types of polymers commonly available. There is a focus on polymers for primary coagulation, their use as coagulant aids, in the recycling of filter backwash waters, and in sludge thickening. Practicalities of polymer use are discussed, with particular attention to polymer toxicity, and the presence of residual polymer in the final drinking water. The questions of polymer degradation and the formation of disinfection by-products are also addressed.
Assuntos
Conservação dos Recursos Naturais , Eletrólitos/isolamento & purificação , Polímeros/isolamento & purificação , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Abastecimento de Água , Desinfetantes/química , Desinfetantes/isolamento & purificação , Desinfetantes/toxicidade , Desinfecção , Eletrólitos/química , Eletrólitos/toxicidade , Filtração , Floculação , Polímeros/química , Polímeros/toxicidadeRESUMO
Polyethyleneimine (PEI) is a synthetic polymer commonly used as precursor base layer in polyelectrolyte multilayer films. However, the biological properties of this cationic macromolecule are poorly understood. The aim of this experimental investigation was to evaluate in vitro the biocompatibility of PEI towards two different human cell lines. The experimental investigation was undertaken on pure titanium (Ti) and nickel-titanium (NiTi) alloy samples with an average surface roughness of Ra=0.3microm. A biological study was undertaken at day 0 (2h after seeding), day 2, day 4 and day 7 to observe the cellular response of fibroblasts and osteoblasts cell lines in terms of morphology, adhesion (as observed by scanning electron microscopy), and viability (Mosmann's test). The results showed that PEI can be successfully deposited onto Ti or NiTi alloy, but generates a detrimental cellular response on both substrates as illustrated by a decrease of both fibroblast and osteoblast adhesion and proliferation over a 7-day culture period. These results suggest that PEI is potentially cytotoxic and may not be biocompatible enough in clinical applications using high molecular weight. As a consequence, polyelectrolyte multilayer films, which are promising in prosthesis and implantology fields, could not be coated with PEI at a high molecular weight. A lower molecular weight should be considered or a more biocompatible molecular base as precursor layer of polyelectrolyte multilayer films would be better to use for a good human bio-integration.
Assuntos
Eletrólitos/toxicidade , Polietilenoimina/toxicidade , Forma Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Humanos , Microscopia Eletrônica de Varredura , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacosRESUMO
A study of the different volume and infusion rates of a new maintenance fluid, Veen 3G, on the general conditions of rats was investigated during the 14 days after infusion. In Experiment I, 100 ml/kg and 200 ml/kg of Veen 3G were infused at a rate of 300 ml/kg/h in male and female rats. Results were compared with those for Gurunon Ringer solution (GRS) in male and female rats. We observed only transient polyuria in animals administered by each dose of Veen 3G and GRS for 0-15 min after infusion. Necropsy was not observed in any of the animals tested 14 days after infusion. In Experiment II, 200 ml/kg of Veen 3G was infused at rates of 200, 400, 800 and 1600 ml/kg/h in male rats. At 800 and 1600 ml/kg/h, irregular respiration and decrease in movement were observed concomitantly with polyuria. Three out of 4 rats died immediately after the infusion of Veen 3G at a rate of 1600 ml/kg/h, and one rat was still alive 14 days after the infusion. In this experiment, 200 ml/kg Veen 3G was safe when we infused at a rate of less than 400 ml/kg/h in male rats. Since this rate is about 27-80 times higher than that used clinically in maintenance treatment, Veen 3G is suggested to be safe, with the exception of polyuria, in clinical situations at the standard infusion rate (5-15 ml/kg/h).
Assuntos
Eletrólitos/toxicidade , Hidratação/efeitos adversos , Glucose/toxicidade , Poliúria/induzido quimicamente , Animais , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Eletrólitos/administração & dosagem , Cor de Olho/efeitos dos fármacos , Feminino , Hidratação/métodos , Glucose/administração & dosagem , Bombas de Infusão/efeitos adversos , Infusões Intravenosas/métodos , Soluções Isotônicas/administração & dosagem , Soluções Isotônicas/toxicidade , Masculino , Dose Máxima Tolerável , Ratos , Ratos Sprague-Dawley , Insuficiência Respiratória/induzido quimicamente , Solução de Ringer , Convulsões/induzido quimicamenteRESUMO
Recently, the authors have shown that marked necrosis and fibrosis of myocardium were observed in rats given alkaline ionized water (AKW). To clarify the cause of myocardial lesions, the activities of myosin ATPase, actomyosin ATPase and creatine kinase (CK) in myocardium of rats given AKW at 15 weeks-old were compared with those in myocardium of rats given tap water (TPW). Furthermore, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of myocardiac myosin and isoelectric focusing (IEF) of myocardiac CK were performed which revealed a distinct difference between AKW and TPW groups. The activities of myosin ATPase and actomyosin ATPase in the AKW group were higher than those in the TPW group, and these elevated activities were caused by the degradation of myosin in the AKW group judging from the SDS-PAGE pattern of myosin. On the other hand, the activity of CK in the AKW group was lower than that in the TPW group, and the IEF pattern of CK showed leakage of myocardiac CK. These results indicate that increases in actomyosin ATPase activity and myosin ATPase activity, plus the decrease in CK activity caused the disorder of coupled reaction in male rats given AKW at 15 weeks-old. It is concluded that this disorder of coupled reaction may cause marked myocardiac necrosis and fibrosis in rats given AKW.