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1.
Adv Exp Med Biol ; 1131: 27-72, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31646506

RESUMO

Ca2+, Na+ and K+- permeable ion channels as well as GPCRs linked to Ca2+ release are important drug targets. Accordingly, high-throughput fluorescence plate reader assays have contributed substantially to drug discovery efforts and pharmacological characterization of these receptors and ion channels. This chapter describes some of the basic properties of the fluorescent dyes facilitating these assay approaches as well as general methods for establishment and optimisation of fluorescence assays for ion channels and Gq-coupled GPCRs.


Assuntos
Bioensaio , Canais Iônicos , Receptores Acoplados a Proteínas-G , Animais , Bioensaio/tendências , Descoberta de Drogas , Corantes Fluorescentes/metabolismo , Humanos , Canais Iônicos/análise , Receptores Acoplados a Proteínas-G/análise
3.
J Assoc Physicians India ; 67(8): 31-34, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31562713

RESUMO

Background: To evaluate the diagnostic accuracy of the Xpert MTB/RIF assay for the detection of M. tuberculosis in pulmonary and extra pulmonary specimens and to compare it with conventional techniques. Methods: A prospective study was conducted with the introduction of GeneXpert in a tertiary care hospital which relied on microscopy and culture for diagnosis of tuberculosis. All patients for whom geneXpert was ordered by the physician were included in the study. Samples which did not have accompanying microscopy or MGIT culture requests were excluded from the analysis of the results. Sensitivity and specificity of GeneXpert was calculated using liquid culture as the reference test. Results: Xpert MTB/RIF assay was performed on 742 samples of which 116 were positive for Mycobacterium tuberculosis. Rifampicin resistance was seen in 6 samples. The pulmonary samples showed a positivity rate of 16.8% while 17.1% of the extrapulmonary samples were positive by GeneXpert. A comparative analysis of microscopy, liquid culture and GeneXpert could be done for 88 samples. Of the 88 geneXpert positive samples, 42 were positive by smear microscopy and MGIT culture while 46 showed discordant results. Of these, 18 samples were positive by geneXpert but showed no growth in MGIT culture. 15 of these patients had undergone anti-tuberculous treatment (ATT) within the past 12 months. The sensitivity of geneXpert was 89.7% and specificity was 95.1% when compared to liquid culture as a gold standard. Sensitivity for extrapulmonary samples was 85.7% and specificity was 98.05%. Conclusion: To conclude, though GeneXpert detects tuberculosis within the shortest possible time, it still suffers from intermediate level sensitivity, which makes culture facilities relevant even in settings that offer an Xpert/Rif assay.


Assuntos
Bioensaio/métodos , Mycobacterium tuberculosis , Centros de Atenção Terciária , Tuberculose/diagnóstico , Farmacorresistência Bacteriana/genética , Humanos , Índia , Microscopia , Estudos Prospectivos , Rifampina , Sensibilidade e Especificidade , Escarro , Tuberculose/microbiologia
4.
Sci Total Environ ; 690: 1151-1161, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31470478

RESUMO

Shooting activities is an important source of Pb in contaminated soils. Lead accumulates in superficial soil horizons because of its low mobility, favouring its uptake by plants and representing a high transference risk to the trophic chain. A combination of phytoremediation with nanoremediation techniques can be used to recover firing range soils and decrease the mobility, bioavailability and toxicity of Pb. This study examines in depth the changes in Pb behaviour in firing range soils by adding hydroxyapatite nanoparticles (HANPs). These nanoparticles (NPs) may immobilise Pb and improve the quality of these areas. The use of HANPs and the Pb effects were assessed in three different species (Sinapis alba L., Lactuca sativa L. and Festuca ovina L.), focusing on their germination and early growth, through phytotoxicity assays. Single extractions with CaCl2 (0.01 M) in soils treated with HANPs show that these NPs retained Pb and reduced highly its availability and mobility. HR-TEM and TOF-SIMS were used to determine the interactions between HANPs and Pb, as well as with soil components. According to TOF-SIMS and HR-TEM/EDS analysis, Pb was mainly retained by HANPs but also associated lightly to organic matter, Fe compounds and silicates. Phytotoxicity assays exposed that S. alba, L. sativa and F. ovina were able to germinate and develop in the firing range soils despite the high available Pb contents before adding HANPs. After adding HANPs, Pb retention increased, favouring the germination and the growth of roots in the three species. These results suggest that HANPs can be used to decrease the availability and the toxicity of Pb without negative effects in the species growth. Accordingly, the combination of phytoremediation and nanoremediation techniques can be a great tool to stabilise these soils, avoiding the Pb transfer to nearby areas and its entry in the trophic chain.


Assuntos
Durapatita/química , Recuperação e Remediação Ambiental/métodos , Chumbo/toxicidade , Nanopartículas/química , Plantas/efeitos dos fármacos , Poluentes do Solo/toxicidade , Bioensaio , Solo , Armas
5.
Toxicol Lett ; 315: 64-76, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31419470

RESUMO

To test the hypothesis that 3-7 ring polycyclic aromatic hydrocarbons (PAHs) are responsible for the prenatal developmental toxicity (PDT) as observed with some petroleum substances (PS), the present study evaluates the PDT potency of DMSO-extracts of 7 heavy fuel oils (HFO), varying in their PAH content, and 1 highly refined base oil (HRBO), containing no aromatics, in the embryonic stem cell test (EST). All DMSO-extracts of HFO inhibit ES-D3 cell differentiation in a concentration-dependent manner and their potency is proportional to the amount of 3-7 ring PAHs they contain. All DMSO-extracts of HFOs also show aryl hydrocarbon receptor (AhR)-mediated activities, as tested in the AhR-CALUX assay. Contrarily, the HRBO-extract tested negative in both assays. Co-exposure of ES-D3 cells with selected DMSO-extracts of PS and the AhR-antagonist trimethoxyflavone, successfully counteracted the PS-induced inhibition of ES-D3 cell differentiation, confirming the role of the AhR in mediating the observed PDT of PS extracts in the EST. A good correlation exists when comparing the in-vitro with the in-vivo PDT potencies of the PS under study. Altogether, our findings corroborate the hypothesis that PS-induced PDT is caused by 3-7 ring PAHs present in these substances and that the observed PDT is partially AhR-mediated.


Assuntos
Células-Tronco Embrionárias/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Petróleo/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Receptores de Hidrocarboneto Arílico/metabolismo , Bioensaio , Poluentes Ambientais/metabolismo , Feminino , Humanos , Petróleo/metabolismo , Gravidez
6.
Chem Commun (Camb) ; 55(72): 10665-10668, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31411210

RESUMO

Adenosine triphosphate is a major vector of chemical energy in living organisms, but its detection is sometimes hindered by complicated physiological sample matrixes. In this work, we demonstrated a ratiometric bioassay for the accurate and sensitive detection of ATP by measuring the 197Au/115In signal ratio of a mass spectrometric core-satellite structure. Validation of the proposed bioassay was successfully demonstrated in cell lysates and human serum samples.


Assuntos
Trifosfato de Adenosina/sangue , Bioensaio , Radioisótopos de Ouro/química , Humanos , Espectrometria de Massas
7.
Exp Parasitol ; 205: 107736, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31442455

RESUMO

Goats are frequently described as an intermediate host for the protozoan Neospora caninum, manifesting the disease mainly by recurrent abortions with placentitis and encephalitis in fetuses. Several reports of natural and experimental infections in cattle and mice show differences in the immune response, and the outcome of the infection can be variable depending on the species affected and by the behavior of the infective strain. This study describes for the first time two Neospora caninum strains isolated from naturally infected goats from the state of Minas Gerais, Brazil. One placenta and one brain from different goats were processed for a first bioassay in gerbils (Meriones unguiculatus). Subsequently, a second bioassay was performed by inoculating the processed brain samples from gerbils into Interferon gamma (IFN-γ) knockout mice (KO mice). Tachyzoites collected from the peritoneal fluid of the KO mice were inoculated into VERO cell monolayers, where they presented a very slow growth rate. The tachyzoites were also inoculated into BALB/c mice with a dose of 106 tachyzoites per animal. After a 5-week follow up, the animals infected with both of the strains developed a strong polarized Th1 response with increased serum and spleen gene expression levels of pro-inflammatory cytokines (mainly IFN-γ and TNF-α) in the first week. Tissue lesions were mild in the animals infected with both strains. Despite the strong immune response preventing an infection in the visceral organs, the parasite was able to reach the brain, causing progressive brain lesions from the second to fifth week post infection. The NC-goat1-infected mice presented with severe meningoencephalitis, but the NC-goat2-infected animals had considerable histological brain lesions only at week 5. Immunohistochemical analysis of the mouse brains revealed a different pattern of inflammatory cells compared to the naturally infected goats. A severe inflammatory infiltrate of CD3+ T lymphocytes was found in the NC-goat1-infected mice. A more discrete infiltrate of CD3+ T cells was found in the NC-goat2-infected animals. Additionally, IBA1 IHC revealed an intense microglial reaction and monocyte perivascular cuffs in the NC-goat1-infected animals and lower microglia/monocyte infiltrates in the NC-goat2-infected mice. This work contributes knowledge on the pathogenicity of new Neospora caninum strains in mice, comparable with other well-established mouse models of the disease, and demonstrates the importance of studying goats as an intermediate host of this parasite.


Assuntos
Coccidiose/veterinária , Doenças das Cabras/parasitologia , Neospora/patogenicidade , Animais , Bioensaio/veterinária , Encéfalo/parasitologia , Encéfalo/patologia , Cercopithecus aethiops , Coccidiose/parasitologia , Coccidiose/patologia , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica , Gerbillinae , Doenças das Cabras/patologia , Cabras , Imuno-Histoquímica/veterinária , Interferon gama/genética , Interferon gama/metabolismo , Fígado/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neospora/isolamento & purificação , Pâncreas/patologia , Placenta/patologia , Gravidez , Baço/metabolismo , Baço/patologia , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Células Vero
8.
An Acad Bras Cienc ; 91(3): e20181008, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31432904

RESUMO

Leaf-cutting ants are considered major pests of agriculture and forestry in the Neotropics. Attractive toxic baits are the prevailing method for managing them. Thus, there is great interest in identifying attractants to incorporate into these baits. Moreover, leaf-cutting ants can avoid toxic baits by associating the attractant with the toxin. We evaluated attractiveness of heptyl butyrate, a volatile compound found in fresh apples and plums. We conducted field experiments with ten colonies of Acromyrmex lobicornis. First, we evaluated the behaviour of ants exposed to heptyl butyrate at 1% by surrounding resources. Then, we compared the attractiveness of heptyl butyrate and orange pulp, the most commonly used attractant. Finally, we evaluated whether heptyl butyrate increases the attractiveness of a carbohydrate resource at varying doses. Heptyl butyrate at 1% attracted 92% more ants than the control and that it was as attractive as orange pulp. Heptyl butyrate paired with sucrose at concentrations of 0.001 and 0.1% was more attractive than sucrose alone, but greater concentrations did not increase sucrose's attractiveness. Therefore, heptyl butyrate could be added to toxic baits to manage A. lobicornis as it is as attractive as the most commonly used attractant and can be applied directly to the pellets.


Assuntos
Formigas/efeitos dos fármacos , Controle de Insetos/métodos , Feromônios/química , Animais , Bioensaio , Feromônios/isolamento & purificação , Feromônios/farmacologia
9.
Exp Parasitol ; 204: 107724, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31279930

RESUMO

Only two drugs are currently available for the treatment of Chagas disease and their effectiveness are unsatisfactory. Photorhabdus luminescens and Xenorhabdus nematophila, two enteric bacteria highly pathogenic to a broad range of insects, have been studied as potential source for bioactive metabolites against protozoa causing neglected tropical diseases. Therefore, we tested the in vitro anti-Trypanosoma cruzi activity of secreted metabolites from these bacteria. The conditioned medium of X. nematophila and P. luminescens showed significant parasiticidal activity in a concentration-dependent manner (IC50XN = 0.34 mg/mL, IC50PL = 1.0 mg/mL). The parasiticidal compound was identified as a small molecule stable to heating and pH changes ranging from 2 to 12. Moreover, anti-Trypanosoma molecules secreted by both bacteria stimulate the trypanocidal activity of macrophages by a mechanism independent of nitric oxide. Summarizing, our studies reveal that P. luminescens and X. nematophila are potential sources of putative novel drugs against Chagas disease.


Assuntos
Proteínas de Bactérias/farmacologia , Photorhabdus/química , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Xenorhabdus/química , Análise de Variância , Animais , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/uso terapêutico , Bioensaio , Doença de Chagas/tratamento farmacológico , Meios de Cultivo Condicionados , Endopeptidase K/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Concentração Inibidora 50 , Temperatura Ambiente , Tripanossomicidas/efeitos adversos , Tripanossomicidas/uso terapêutico , Trypanosoma cruzi/crescimento & desenvolvimento
10.
Exp Parasitol ; 204: 107729, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31348914

RESUMO

The objectives of this study are to: (1) evaluate the in vitro acaricidal effect of 54 Metarhizium anisopliae strains, six Beauveria bassiana strains and one Purpureocilium lilacinum strain, against the larvae of two populations of Rhipicephalus microplus (multi-resistant and susceptible to chemical acaricides); and (2) determine the lethal concentrations required to eliminate the 50% (LC50) and 99% (LC99) of larvae through the use of entomopathogenic fungi (EF) with high acaricidal effects. The mortality percentage was evaluated by larval immersion tests at a dose of 1 × 108 conidia/mL for each fungal strain. For calculating LC50 and LC99, four doses (1 × 108, 1 × 107, 1 × 106 and 1 × 105) were used. Nine strains of M. anisopliae and the P. lilacinum strain showed a high mortality percentage in the R. microplus larvae of both populations. The best strains that showed the lowest values of LC50 and LC99 for tick elimination were MaV50 and PlV01. In conclusion, several strains of entomopathogenic fungi showed a high acaricidal effect against the R. microplus larvae of both populations, suggesting that these fungi might be a promissory adjuvant in the control of R. microplus, including those who are resistant. Finally, the discovery of a P. lilacinum strain with a high acaricidal effect is also reported.


Assuntos
Acaricidas/farmacologia , Fungos/patogenicidade , Controle Biológico de Vetores/métodos , Rhipicephalus/microbiologia , Microbiologia do Solo , Animais , Beauveria/patogenicidade , Bioensaio/veterinária , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/parasitologia , Doenças dos Bovinos/prevenção & controle , Feminino , Hypocreales/patogenicidade , Resistência a Inseticidas , Larva/efeitos dos fármacos , Larva/microbiologia , Dose Letal Mediana , Masculino , Metarhizium/patogenicidade , México , Rhipicephalus/efeitos dos fármacos , Infestações por Carrapato/tratamento farmacológico , Infestações por Carrapato/parasitologia , Infestações por Carrapato/veterinária , Virulência
11.
J Chromatogr A ; 1603: 433-437, 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31288929

RESUMO

An efficient strategy for the selection of active components based on counter-current fractionation and bioassay-guided separation was established in the present work. Blaps rynchopetera Fairmaire was an edible medicinal insect. Its extract showed the potential RAW264.7 macrophage cell inhibitory activity. After extraction with different solvents, the active components were enriched in ethyl acetate. In order to further track the active compounds, the ethyl acetate extraction was divided into 14 fractions by means of HSCCC. The results showed that the activities of F6 and F7 were significant higher than the others. Two compounds, hydroxytyrosol and 4-ethylbenzene-1,3-diol, were separated from the mixture of F6 and F7 by column chromatography and their chemical structures were confirmed by MS, 1H NMR and 13C NMR. The IC50 of hydroxytyrosol and 4-ethylbenzene-1,3-diol against RAW264.7 macrophage cell were 38.24 ±â€¯0.26 µg/mL and 103.26 ±â€¯0.29 µg/mL, respectively, indicating that hydroxytyrosol was the major active ingredient responsible for the RAW264.7 inhibitory activity of Blaps rynchopetera Fairmaire.


Assuntos
Bioensaio/métodos , Distribuição Contracorrente/métodos , Insetos/química , Animais , Fracionamento Químico , Cromatografia Líquida de Alta Pressão , Camundongos , Extratos Vegetais/farmacologia , Células RAW 264.7 , Solventes/química
12.
Environ Monit Assess ; 191(8): 513, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31346830

RESUMO

In this study, a method was developed to evaluate the degradation of haloacetic acids (HAAs) in water by a heterogenous Fenton-like process catalyzed by cobalt-doped magnetite nanoparticles (Fe3 - xCoxO4), extraction of the contaminants by liquid-liquid extraction (LLE), and analysis by gas chromatography-mass spectrometry (GC-MS). The developed method was efficient in the degradation of HAAs, with the following degradation values: 63%, 62%, 30%, 39%, 37%, 50%, 84%, 41%, and 79% for monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, trichloroacetic acid, bromochloroacetic acid, dibromoacetic acid, bromodichloroacetic acid, dibromochloroacetic acid, and tribromoacetic acid compounds, respectively. Through the application of the Allium cepa test, the cytotoxicity, genotoxicity, and mutagenicity of HAAs were evaluated. The results confirm its genotoxic and mutagenic effects on Allium cepa meristematic cells. Through this study, it was possible to verify the effectiveness of the developed method and its potential as a proposal for environmental remediation.


Assuntos
Bioensaio , Cloroacetatos/toxicidade , Mutagênicos/toxicidade , Testes de Toxicidade , Acetatos/toxicidade , Ácido Acético , Dano ao DNA , Ácido Dicloroacético/toxicidade , Monitoramento Ambiental , Cromatografia Gasosa-Espectrometria de Massas , Hidrocarbonetos Bromados/toxicidade , Ácido Tricloroacético/toxicidade , Água/análise , Abastecimento de Água
13.
Chemistry ; 25(53): 12270-12274, 2019 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-31282008

RESUMO

DNA walking machines opened new avenues for the biosensing and demonstrated great success in the past few years. Since DNA machines are mainly nonequilibrium systems driven by dynamic interactions, the matrix effects on DNA machines is a bottleneck and more intricate than common DNA-mediated assays, especially for complicated physiological samples. Herein, to realize an accurate and reliable quantitative machine, a ratiometric DNA walking machine was developed in human serums and cell lysates based on the elemental isotope ratio measurement. The target DNA-triggered walking machine converted and amplified biological signals into mass spectrometric signal ratios (197 Au/115 In) via a burnt-bridge mechanism. Under the optimized conditions, the limit of detection (LOD, 3σ) was 8 fM for target DNA, with a dynamic linear range of 0.05-0.7 pM. The ratiometric DNA walking machine was directly applied in human serum samples with satisfactory recoveries of 94 to 105 %, demonstrating an excellent stability and a high accuracy. Combining the aptamer-based specific recognition, the proposed DNA machine is expected to be a versatile platform for other targets, such as small biomolecules and proteins.


Assuntos
DNA/química , Proteínas/química , Bioensaio , Humanos
14.
Chemosphere ; 233: 936-945, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31340421

RESUMO

For an integrated ecological risk assessment of marine sediment contamination, the determination of target-compound concentrations by e.g. mass spectrometric methods is not sufficient to explain sediment toxicity. Due to the presence of a multitude of environmental contaminants in this complex matrix causing a mixed toxicity, the identification and assessment of main toxicants is a challenge. One approach in identifying main toxicants is the application of effect-directed analysis (EDA). In this study, an EDA approach was developed using high performance thin layer chromatography (HPTLC) coupled to bioluminescence bacteria detection with Aliivibrio fischeri for the determination of marine sediments acute toxicity. In a first attempt, the HPTLC separation was optimized with a fast, two-step gradient to separate main hydrophobic organic contaminant (HOC) classes found in marine sediments. An easy-to-use evaluation script for the resulting bioluminescence inhibition images was programed using R. The developed method was applied to sediment extracts of two different sample sets: (i) Fourteen marine sediment samples from the German Bight representing a wide range of contaminant loads and sediment properties and (ii) sediment samples from a core representing temporal trends of contamination. Results from the HPTLC-bioluminescence bacteria assay were compared to HOC concentrations determined by GC-MS/MS. A correlation of the determined inhibition Γ-values for the PAH inhibition zone to PAH concentrations showed a very good agreement (R2 = 0.91). The results of this study were used to evaluate the suitability of the EDA approach to be used as an assessment tool for marine sediments.


Assuntos
Aliivibrio fischeri/metabolismo , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química , Substâncias Perigosas/análise , Poluentes Químicos da Água/toxicidade , Poluição Química da Água/análise , Bioensaio , Cromatografia em Camada Delgada , Cromatografia Gasosa-Espectrometria de Massas , Medição de Risco , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/análise
15.
Anal Chim Acta ; 1078: 182-188, 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31358218

RESUMO

Early detection of toxic proteases in food matrices plays a major role in preventing the occurrence of diseases as well as outbreaks. However, on-site detection of proteases, for instance, botulinum, anthrax and cholera in food matrices remains challenging due to their extremely low lethal dose levels. Here, we report a lateral flow assay (LFA) in a dipstick format for on-site visual detection of proteases in food matrices. The light chain of BoNT serotype A (BoNT/A LC) is used as a model system for validation of the proposed assay using magnetic beads conjugated to a synthetic peptide that provide a specific cleavage site for BoNT/A LC. Magnetic beads serve as both reporters for visual detection and as facilitators for sample clean-up, owing to the efficient magnetic separation protocol adopted. Digestion of the peptide substrate by BoNT/A LC for 5 h followed by the dipstick assay yields a reduction in color intensity of the test line on the dipstick compared to the control line obtained using an un-cleaved peptide substrate. Concentration dependent responses for the assay in carrot juice were obtained with a limit of detection (LOD) of 1 nM/2.5 nM (with/without amplification), also supported by RGB (ΔE) analysis, indicating the potential of the proposed methodology for on-site assaying of proteases in food matrices. Unlike typical affinity-based assays that yield a collective response for the active and inactive forms of the proteases, the proposed functional LFA targets only the active form, thereby enabling a more precise analysis for preventing potential false-positives. The proposed approach could be extended for detection of BoNT serotypes and other proteases in food matrices, upon utilizing appropriate substrates with specific cleavage sites.


Assuntos
Bioensaio/métodos , Toxinas Botulínicas Tipo A/análise , Sucos de Frutas e Vegetais/análise , Sequência de Aminoácidos , Anticorpos/imunologia , Toxinas Botulínicas Tipo A/química , Daucus carota/química , Limite de Detecção , Fenômenos Magnéticos , Peptídeos/química , Polietilenoglicóis/química , Estudo de Prova de Conceito , Estreptavidina/química
16.
Sci Total Environ ; 690: 636-646, 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31301504

RESUMO

Publicly available chemical assessments of hydraulic fracturing related waters are generally based on shale gas practices in the U.S. There is a lack of information on hydraulic fracturing related gas development from EU countries and more generally on other types of extractions. This research fills this knowledge gap by presenting chemical and bioassay assessments of hydraulic fracturing related waters from a tight gas development in the Netherlands. Fracturing fluid, flowback water and groundwater from surrounding aquifers before and after the actual fracturing were analysed by means of high resolution liquid chromatography tandem mass spectrometry, the Ames test and three chemical activated luciferase gene expression bioassays aimed at determining genotoxicity, oxidative stress response and polyaromatic hydrocarbon contamination. After sample enrichment a higher number of peaks can be found in both fracturing fluid and flowback samples. No clear differences in chemical composition were shown in the groundwater samples before and after hydraulic fracturing. Preliminary environmental fate data of the tentatively identified chemicals points towards persistence in water. Clear genotoxic and oxidative stress responses were found in the fracturing fluid and flowback samples. A preliminary suspect screening resulted in 25 and 36 matches in positive and negative ionisation respectively with the 338 possible suspect candidates on the list. Extensive measures relating to the handling, transport and treatment of hydraulic fracturing related waters are currently in place within the Dutch context. The results of the present study provide a scientific justification for such measures taken to avoid adverse environmental and human health impacts.


Assuntos
Monitoramento Ambiental , Fraturamento Hidráulico , Poluentes Químicos da Água/análise , Bioensaio , Países Baixos , Campos de Petróleo e Gás
17.
Bol. latinoam. Caribe plantas med. aromát ; 18(4): 359-377, jul. 2019. tab
Artigo em Inglês | LILACS | ID: biblio-1008174

RESUMO

Plant species have been used for therapeutic purposes since ancient times and are still in use today since these products represent a source of raw material for the production of phytotherapeutic formulations. Screening and investigation of plants with pharmacological potential require the evaluation of characteristics related to their action, efficacy and safety in different steps. Among these steps, pre- clinical trials are used to evaluate the properties of the test product in in vitro experiments, such as cytotoxicity assays. Within this context, this study consists of a bibliometric analysis of some in vitro cytotoxicity and toxicity assays in erythrocytes used during bioprospecting of medicinal plants. The results demonstrated the wide application of erythrocytes to evaluate the biological effects of medicinal plant extracts. The methods were found to be valid and effective for the preliminary investigation of the in vitro cytotoxicity and toxicity of plant products.


El uso de especies vegetales para fines terapéuticos es una práctica histórica y todavía bastante actual, ya que estos productos pueden representar una fuente de materia prima para la producción de formulaciones fitoterápicas. En investigación de plantas con potencial farmacológico requiere la evaluación de su acción, eficacia y seguridad, a través de diferentes etapas. Entre estas, en los ensayos preclínicos se evalúan las propiedades del producto-prueba en experimentos in vitro, tales como ensayos de citotoxicidad, entre otros. En este aspecto, el presente estudio consiste en un análisis bibliométrico acerca de algunas pruebas de citotoxicidad y toxicidad in vitro en eritrocitos realizados en los ensayos de bioprospección de plantas medicinales. Los resultados evidencian la amplia utilización de eritrocitos para la evaluación de los efectos biológicos de extractos de plantas medicinales, apuntándolos como métodos válidos y eficaces para la investigación preliminar de la citotoxicidad y toxicidad in vitro de productos vegetales.


Assuntos
Bioensaio/métodos , Extratos Vegetais/toxicidade , Eritrócitos/efeitos dos fármacos , Antioxidantes/toxicidade , Fragilidade Osmótica , Estresse Oxidativo , Eritrócitos/citologia , Bioprospecção , Hemólise/efeitos dos fármacos
18.
Anticancer Res ; 39(7): 3413-3418, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31262863

RESUMO

One aim of cell-based in vitro assays is to identify the best drug candidate to develop using the best tumor cell model. This is challenging in every anticancer drug discovery process. Briefly, we summarize the parameters to be taken into account when performing in vitro cell assays, in order to obtain reliable and reproducible results, which was fundamentally discussed by lecturers at the educational course on preclinical and early-phase clinical pharmacology studies, at the 40th Winter Meeting of the Pharmacology and Molecular Mechanisms Group of the European Organization for Research and Treatment of Cancer. Moreover, specific cellular sensitivity tests are described. In addition to monolayer in vitro cell models for the screening of new potential candidate drugs, three-dimensional tumor/cell tissue models are emerging as new pre-clinical tools that more closely reflect the in vivo microenvironment. Therefore, the use of different in vitro models for drug screening can enhance the predictability and reliability of pre-clinical drug-discovery phases and target validation.


Assuntos
Avaliação Pré-Clínica de Medicamentos , Farmacologia Clínica/métodos , Bioensaio , Técnicas de Cultura de Células , Humanos
19.
Chem Commun (Camb) ; 55(50): 7211-7214, 2019 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-31165808

RESUMO

A label-free and universal photosensitization colorimetric assay based on target-induced dsDNA termini switching has been developed for the analysis of nucleic acids, proteins, small molecules and metal ions. This strategy is highly sensitive and versatile, the principle of which will be desirable for various biosensor developments and applications.


Assuntos
Colorimetria/métodos , DNA/química , Metais/química , Ácidos Nucleicos/química , Proteínas/química , Bioensaio/métodos , Conformação de Ácido Nucleico , Conformação Proteica
20.
Malar J ; 18(1): 198, 2019 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-31196091

RESUMO

BACKGROUND: From 2011 to 2014, an indoor residual spray (IRS) programme for malaria vectors control was implemented in six health districts in Senegal. The main objective of the present study was to evaluate the efficacy of bendiocarb (FICAM WP 80) sprayed on different wall surfaces and its impact on malaria vectors. The entomological monitoring activities were carried out monthly in five treated sentinel villages and one control untreated village in each district. METHODS: The residual efficacy of bendiocarb applied at a dosage of 0.4 g/sq m was monitored for a period up to 9 months post-IRS using WHO cone bioassay method. This assay consisted to expose 2-5 days old unfed susceptible Anopheles coluzzii females to sprayed walls for a period of 30 min. The mortality rates after 24 h post-exposure were estimated and compared between the different types of walls sprayed in each sentinel village. RESULTS: The results showed that the residual efficacy varied between the different sprayed walls, from one sentinel village to another and between the different campaigns. The FICAM had a residual efficacy of 3-6 months post-IRS on mud and cement wall surfaces. In some cases, the observed mortality rates were much higher than those reported elsewhere particularly during the first campaign in all the six districts. CONCLUSIONS: The FICAM was found to be effective with a residual efficacy varying from 3 to 6 months. If the quality of the IRS application is excluded as a possible explanation of the short efficacy duration, the results suggest at least two rounds of treatments in order to cover the rainy season that lasts 5 to 6 months in the area. Such treatments could be carried out before the intensification of the rains in July and August in order to better cover the transmission period that occurs between late August and October in the area.


Assuntos
Aerossóis/farmacologia , Anopheles/efeitos dos fármacos , Inseticidas/farmacologia , Controle de Mosquitos/métodos , Mosquitos Vetores/efeitos dos fármacos , Fenilcarbamatos/farmacologia , Aerossóis/administração & dosagem , Animais , Bioensaio , Entomologia , Feminino , Humanos , Inseticidas/administração & dosagem , Fenilcarbamatos/administração & dosagem , Senegal , Inquéritos e Questionários , Fatores de Tempo
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