Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 72
Filtrar
1.
Environ Res ; 234: 116030, 2023 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-37142080

RESUMO

Intensification of crop cultivation can have detrimental environmental consequences that however can be prevented by monitoring of the specific biological indicators sensitive to changes in the ambient environment. In this study the impact of crop type (spring wheat and corn) and cultivation intensity on the community of ground beetles (Coleoptera: Carabidae) in the forest-steppe of Western Siberia was investigated. A total of 39 species from 15 genera were collected. Ground beetles' community was characterized by a high evenness of species distribution across the agroecosystems. The average Jaccard's similarity index for species presence/absence was 65%, and for abundance it was 54%. The significant difference in the distribution of predatory and mixophytophages ground beetles in wheat crops (U test, P < 0.05) can be justified by the constant suppression of the weed component and the use of insecticides that lead to the dominance of the predators. Fauna of wheat crops was more diverse than that in corn (Margalef index, U test, P < 0.05). No significant differences in biological diversity indexes, except for the Simpson dominance index (U test, P < 0.05, wheat), were found in ground beetle communities in crops at different levels of intensification. A certain differentiation of predatory species was caused by the selective occurrence of the litter-soil species, especially abundant in the row-crop. The specificity of the ground beetle community of corn crops may have been caused by repeated inter-row tillage, which influenced the increase in porosity and topsoil relief and contributed to the creation of favorable microclimatic conditions. In general, the applied level of agrotechnological intensification had no significant effect on the species composition and ecological structure of beetle communities in agrolandscapes. The use of bioindicators made it possible to assess the environmental sustainability of the agricultural environment and also creates the prerequisites for the development of ecologically directed correction of agrotechnological operations in agroecosystem management.


Assuntos
Besouros , Ecossistema , Animais , Biomarcadores Ambientais , Biodiversidade , Solo , Triticum , Zea mays , Produtos Agrícolas
2.
Toxicol Rep ; 8: 1207-1219, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34189057

RESUMO

Coal dust is a source of pollution not only for atmospheric air but also for the marine environment. In places of storage and handling of coal near water bodies, visible pollution of the water area can be observed. Coal, despite its natural origin, can be referred to as anthropogenic sources of pollution. If coal microparticles enter the marine environment, it may cause both physical and toxic effects on organisms. The purpose of this review is to assess the stage of knowledge of the impact of coal particles on marine organisms, to identify the main factors affecting them, and to define advanced research directions. The results presented in the review have shown that coal dust in seawater is generally not an inert substance for marine organisms, and there is a need for further study of the impact of coal dust particles on marine ecosystems.

3.
Sci Rep ; 8(1): 17169, 2018 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-30464198

RESUMO

Arc welding operations are considered to be risky procedures by generating hazardous welding fume for human health. This study focuses on the key characteristics, as well as dispersion models, of welding fumes within a work zone. Commercial and widely used types of electrodes with various types of covering (rutile, basic, acidic and rutile-cellulose) were used in a series of experiments on arc welding operations, under 100 and 150 amps of electric current. According to the results of this study, maximum levels of pollution with particles of PM10 fraction occur in the workspace during arc welding operations. Disregarding the types of electrodes used, the 3D models of dispersion of the РМ10 particles at the floor plane exhibit corrugated morphologies while also demonstrate high concentrations of the РМ10 particles at distances 0-3 m and 4-5 m from the emission source. The morphology of these particles is represented by solid and hollow spheres, 'nucleus-shell' structures, perforated spheres, sharp-edged plates, agglomerates of the tree-like (coral) shape. At last the bifractional mechanism of fume particle formation for this type of electrodes is also shown and described. In this article results are reported, which demonstrate the hazards of the arc welding process for human health. The results of the characterization of WFs reported improve our understanding of risks that these operations pose to human health and may strengthen the need for their control and mitigation.


Assuntos
Poluentes Atmosféricos/análise , Eletrodos , Material Particulado/análise , Fumaça , Soldagem/métodos , Humanos
4.
Toxicol Rep ; 5: 1107-1113, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30450285

RESUMO

Since ancient times the concept of dose response, from a toxicological perspective, has been a matter of concern. Already by the 8th century BC and over the years, many enlightened people have attempted to interpret this phenomenon, observing and coming across its results and practical implementation through exposure to chemical substances, either from natural or synthetic sources. Nowadays, the environmental exposure of human populations to chemicals in terms of quantity and quality might differ. Nevertheless, dose response still remains an issue joining hands with scientific and technological progress. The aim of the present review is not only to briefly recount the history of the dose response concept, from ancient time theories to novel approaches, but also to draw the outline of challenges and requirements toxicology science needs to fulfill.

5.
Toxicol Rep ; 5: 224-230, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29854593

RESUMO

Despite the fact that environmental pollution due to motorcycle exhaust gases reports a great increase, motorcycle production exhibits a great increase through the last years. Countries of Asia and Africa are reported to be the major regions where two-wheeled vehicles are a major transportation mode, with tens of millions of units sold per year. Motorcycle exhaust particles are considered to be the major contributor to environmental pollution due to their airborne dispersion, containing great amount of polycyclic aromatic hydrocarbons (PAHs). This study aims at reporting an objective analysis of the main sources of the ambient air pollution as also particle size distribution and chemical composition analysis of particulate matter originated from the exhausts of two-wheeled vehicles used in the territory of Vladivostok, Russia. Various types of two-wheeled vehicles were examined (motorcycles, ATVs, scooters and wet bikes) using different types of engine and fuel system. Experimental results showed that there was no clear relation to the particle size distribution with the engine displacement of motorcycle and the number of strokes and the fuel system. Instead, there were reported two clear assumptions. The first one is that regarding to the motorcycle brand, a few samples did not exhibit a great percentage of PM10 fraction. The second one is that more modern vehicles, that have a harmful gas afterburning system, are usually the source of an increased percentage of PM10 emitted particles. At last, it should be mentioned that the laser particle size analysis method is capable of determining the particle sizes after their agglomeration whereas the optical morphometry method allows to determine the real particle size of emissions. In conclusion, it can be pointed out that the agglomeration of particles can lead to the reduction in the toxicity of particles emissions originated from two wheeled-vehicles.

6.
Environ Res ; 166: 473-480, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29957500

RESUMO

The effect of carbon and silicon nanotubes (CNTs and SiNTs) and carbon nanofibers (CNFs) to microscopic marine algae Heterosigma akashiwo was studied, using algal growth inhibition for 3 days (acute effect) and 7 days (chronic effect) as toxicity endpoints. The criterion of the toxic effect was the statistically significant reduction of the number of algal cells in the exposed samples compared to the control. Samples did not demonstrate toxic effects at doses 1 mg/l and 10 mg/l. CNTs and SiNTs samples at 100 mg/l exhibited both acute and chronic toxic effects. We assume that the main cause of cell death in these samples was related to the mechanical damage of cell integrity. CNFs at concentrations of 100 mg/l did not inhibit algal growth, but cells with irregular shapes were observed, which were not observed after exposure to CNTs and SiNTs. Nickel impurities present in CNFs samples are presumably the main cause of observed cell deformations.


Assuntos
Microalgas/efeitos dos fármacos , Nanofibras/toxicidade , Nanotubos de Carbono/toxicidade , Silício/toxicidade
7.
Biomed Rep ; 8(2): 111-116, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29435268

RESUMO

Telomeres are repeated 5'-TTAGGG-3' sequences at the end of chromosomes, which maintain genomic stability. Their length is related to a number of diseases that affect humans. Apart from cancer, cardiovascular diseases, diabetes and other, telomere length has been associated with chronic diseases. Chronic mental illness includes various types of mental disorders with the most common being depression, schizophrenia and stress-anxiety. The aim of this review is to summarize the current state of knowledge on the role of telomeres in these disorders and to compare telomere length variations in patients receiving medication and patients not taking treatment. Most studies report reduced telomere length in patients suffering from mental disorders, compared to the general population. Since the factors that can affect telomere length are various, more experiments and investigations are required to understand the general impact of different factors on telomere length.

8.
Exp Ther Med ; 13(6): 2960-2968, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28587367

RESUMO

The aim of the present study was to examine the seasonality of hypospadias in Greece in an attempt to elucidate the aetiology. All boys born between 1991-1998, who underwent hypospadias repair at 'Aghia Sophia' Children's Hospital, Athens (n=542) were analysed. All Greek live-born males during the same period (population at risk; m=421,175) served as the controls. Seasonality by month of birth was evaluated with specific statistical tools. Meteorological parameters were also analysed. All tests yielded significant results, suggesting a simple harmonic prevalence pattern (highest/lowest: autumn, peak in October/spring, trough in April). Therefore, the first trimester of hypospadiac gestations coincides more frequently with winter. Meteorological parameters varied seasonally (maximal sunlight; air temperature in summer/minimal in winter, maximal rainfall in winter/minimal in summer) and were strongly associated pairwise. Hypospadiac birth prevalence follows a simple harmonic seasonal pattern and is associated with that of cryptorchidism in Greece. The coincidence of the first or third trimester of a potentially genetically influenced gestation with winter could lead to the phenotypic expression of hypospadias or cryptorchidism, respectively. The potential role of a cyclic-varied androgen-production stimulator, such as human chorionic gonadotrophin may be speculated. The seasonality of a common environmental factor acting directly/indirectly may contribute to these patterns, and possibly to the common pathogenesis of these congenital malformations.

9.
Hum Exp Toxicol ; 36(6): 554-564, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28539089

RESUMO

In real life, consumers are exposed to complex mixtures of chemicals via food, water and commercial products consumption. Since risk assessment usually focuses on individual compounds, the current regulatory approach doesn't assess the overall risk of chemicals present in a mixture. This study will evaluate the cumulative toxicity of mixtures of different classes of pesticides and mixtures of different classes of pesticides together with food additives (FAs) and common consumer product chemicals using realistic doses after long-term exposure. Groups of Sprague Dawley (CD-SD) rats (20 males and 20 females) will be treated with mixtures of pesticides or mixtures of pesticides together with FAs and common consumer product chemicals in 0.0, 0.25 × acceptable daily intake (ADI)/tolerable daily intake (TDI), ADI/TDI and 5 × ADI/TDI doses for 104 weeks. All animals will be examined every day for signs of morbidity and mortality. Clinical chemistry hematological parameters, serum hormone levels, biomarkers of oxidative stress, cardiotoxicity, genotoxicity, urinalysis and echocardiographic tests will be assessed periodically at 6 month intervals. At 3-month intervals, ophthalmological examination, test for sensory reactivity to different types of stimuli, together with assessment of learning abilities and memory performance of the adult and ageing animals will be conducted. After 24 months, animals will be necropsied, and internal organs will be histopathologically examined. If the hypothesis of an increased risk or a new hazard not currently identified from cumulative exposure to multiple chemicals was observed, this will provide further information to public authorities and research communities supporting the need of replacing current single-compound risk assessment by a more robust cumulative risk assessment paradigm.


Assuntos
Aditivos Alimentares/toxicidade , Praguicidas/toxicidade , Medição de Risco/métodos , Animais , Simulação por Computador , Consenso , Exposição Ambiental , Feminino , Contaminação de Alimentos , Humanos , Masculino , Ratos Sprague-Dawley
10.
Food Chem Toxicol ; 96: 273-9, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27539747

RESUMO

The aim of the present study was to evaluate the cytotoxicity against MCF-7 cells and acute intraperitoneal toxicity of amphiphilic poly-N-vinylpyrrolidone nanoparticles to confirm possibility of their application for creation of novel drug delivery systems. The effect of cellular uptake of polymeric nanoparticles on human cancer cell line MCF-7 cells was investigated by MTT assay. MTT analysis showed that tested amphiphilic polymers were essentially non-toxic. In acute toxicity studies, LD50 and other toxicity indexes were evaluated, under which no deaths or treatment related complications were observed even in high concentration treatment for 14 days of experiment. For histological analysis, organs of the animals were weighed and examined. No animal died during the study and no significant changes have been observed regarding body weight, feed consumption, organ weight or histological data. Obtained results show that amphiphilic poly-N-vinylpyrrolidone nanoparticles possessed no toxicity against cells and in animals after intraperitoneal administration. Thus, amphiphilic PVP nanoparticles demonstrate high potential as carriers for novel high-effective drug delivery systems.


Assuntos
Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Nanopartículas/administração & dosagem , Polímeros/química , Pirrolidinonas/toxicidade , Animais , Materiais Biocompatíveis/administração & dosagem , Materiais Biocompatíveis/toxicidade , Peso Corporal/efeitos dos fármacos , Feminino , Humanos , Interações Hidrofóbicas e Hidrofílicas , Células MCF-7 , Masculino , Camundongos Endogâmicos BALB C , Nanopartículas/química , Pirrolidinonas/administração & dosagem , Testes de Toxicidade Aguda
11.
Environ Res ; 147: 207-11, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26894816

RESUMO

Measuring chronic pesticide exposure is important in order to investigate the associated health effects. Traditional biological samples (blood/urine) are difficult to collect, store and transport in large epidemiological studies in settings such as rural Asia. We assessed the acceptability of collecting hair samples from a rural Sri Lankan population and found that this method of data collection was feasible. We also assessed the level of non-specific metabolites (DAPS) of organophosphate pesticides in the hair samples. The median concentration (pg/mg) of each DAP was: diethyl phosphate: 83.3 (IQI 56.0, 209.4); diethyl thiophosphate: 34.7 (IQI 13.8, 147.9); diethyl dithiophosphate: 34.5 (IQI 23.4, 55.2); and dimethyl phosphate: 3 (IQI 3, 109.7). Total diethylphosphates were recovered in >80% of samples and were positively correlated with self-reported pesticide exposure.


Assuntos
Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Cabelo/química , Organofosfatos/análise , Praguicidas/análise , População Rural/estatística & dados numéricos , Adolescente , Adulto , Idoso , Estudos Transversais , Poluentes Ambientais/metabolismo , Estudos de Viabilidade , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Masculino , Pessoa de Meia-Idade , Organofosfatos/metabolismo , Praguicidas/metabolismo , Sri Lanka , Adulto Jovem
12.
Environ Res ; 137: 246-55, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25594493

RESUMO

Heavy metals have been associated with many fish deformities in natural populations and in laboratory produced specimens as well. Deformities in general have devastating effects on fish populations since they affect the survival, the growth rates, the welfare and their external image. Although the embryonic stage in respect to heavy metal exposure has been extensively studied, there is not much information available as to what happens in fish larvae and adults. In the present article, we present the available information on the effect of heavy metals on fish larvae deformities. We also address the need for more research towards the effects of metals on the subsequent life stages in order to assess the long-term consequences of heavy metal poisoning on fish organisms and possibly correlate these consequences with the environmental contamination (use as biomarkers).


Assuntos
Embrião não Mamífero/anormalidades , Embrião não Mamífero/efeitos dos fármacos , Peixes/embriologia , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Peixes/metabolismo
13.
Hum Exp Toxicol ; 33(11): 1099-112, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25205739

RESUMO

A grape pomace extract enhanced antioxidant mechanisms in muscle and endothelial cells both in the absence and in the presence of oxidative stress-induced agent tert-butyl hydroperoxide (tBHP). In particular, muscle (C2C12) and endothelial (EA.hy926) cells were treated with the extract at noncytotoxic concentrations for 24 h, and the oxidative stress markers, total reactive oxygen species (ROS), glutathione (GSH), thiobarbituric reactive substances (TBARS), and protein carbonyl levels were assessed. The results showed that the grape extract treatment reduced significantly ROS, TBARS, and protein carbonyl levels and increased GSH in C2C12 cells, while it increased GSH and decreased protein carbonyl levels in EA.hy926 cells. In the presence of tBHP, the grape extract treatment in C2C12 cells reduced significantly ROS, TBARS, and protein carbonyls and increased GSH compared with tBHP alone treatment, while, in EA.hy926 cells, the extract decreased significantly TBARS and protein carbonyls but increased GSH. The antioxidant potency of the extract was different between muscle and endothelial cells suggesting that the antioxidant activity depends on cell type. Moreover, the antioxidant activity of the grape extract, in both cell lines, exerted, at least in part, through increase in GSH levels. The present work is the first to report the effects of grape extract shown for skeletal muscle cells.


Assuntos
Antioxidantes/farmacologia , Células Endoteliais/efeitos dos fármacos , Flavonoides/farmacologia , Células Musculares/efeitos dos fármacos , Extratos Vegetais/farmacologia , Vitis , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Endoteliais/metabolismo , Glutationa/metabolismo , Humanos , Camundongos , Células Musculares/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
14.
Reprod Toxicol ; 46: 98-105, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24685944

RESUMO

The aim of this study was to evaluate fetal exposure to organophosphate pesticides (OPs) by measuring their non-specific dialkyl-phosphate metabolites (DAPs) in amniotic fluid (AF), and to examine the potential association between prenatal exposure and fetal growth. AF samples were collected from 415 women during the second gestational trimester. The determined OPs metabolites were DMP, DMTP, DEP, DETP, and DEDTP. DAPs were extracted by liquid-solid extraction, derivatized and analyzed by gas chromatography-mass spectrometry. 97.8% of AF samples were positive for at least one DAP. DAPs levels did not differ between urban and rural areas. Macrosomic neonates have significantly higher sum levels of DMPs (p=0.043), which exerted a linear positive association with birth-weight centile (b=4.43, p=0.016). Conclusively, as DAPs are detectable in AF they may be used as a potential biomarker of fetal exposure to OPs. Sum levels of DMPs appear to be associated with birth weight independently of other covariates.


Assuntos
Líquido Amniótico/química , Biomarcadores/análise , Organofosfatos/metabolismo , Organofosfatos/toxicidade , Adulto , Exposição Ambiental , Feminino , Grécia , Humanos , Recém-Nascido , Idade Materna , Praguicidas , Gravidez , Reprodutibilidade dos Testes
15.
Cell Mol Biol (Noisy-le-grand) ; 59(1): 58-66, 2013 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-24200021

RESUMO

Publications produced over the past 20 years regarding the concentration of xenobiotics in human and dietary milk were evaluated, focusing primarily on persistent organic pollutants (e.g. polychlorinated biphenyls, flame retardants), pesticides (e.g organochlorine) and mycotoxins. In general, countries of low industrialization rate present low levels of dietary milk contamination with dioxins compared to those with high rate of industrialization. According to published data, the most common persistent organic pollutants detected in breast and dietary milk are dichlorodiphenyltrichloroethane compounds, hexachlorocyclohexane, and hexachlorobenzene. Even though the potential risks of persistent organic pollutants in human milk have been acknowledged, the beneficial effect of breastfeeding as the optimal food source for newborn babies should not be disregarded. Especially when sharing information with the general public, it should be made clear that the presence of dioxins and persistent organic pollutants in human milk is not an indication for avoiding breastfeeding. The implications of xenobiotics in human and dietary milk is a matter of growing importance and warrants future work given its important health effects.


Assuntos
Poluentes Ambientais/química , Leite/metabolismo , Micotoxinas/química , Xenobióticos/química , Animais , Poluentes Ambientais/toxicidade , Humanos , Hidrocarbonetos/química , Hidrocarbonetos/toxicidade , Imunidade/efeitos dos fármacos , Leite/química , Micotoxinas/toxicidade , Neurônios/efeitos dos fármacos , Praguicidas/química , Praguicidas/toxicidade , Xenobióticos/toxicidade
16.
Hum Exp Toxicol ; 31(3): 258-65, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22027507

RESUMO

In this pilot study, we examined the validity and usefulness of hair nicotine-cotinine evaluation as a biomarker of monitoring exposure to tobacco. Head hair samples were collected from 22 infants (<2 years of age) and 44 adults with different exposures to tobacco (through either active or passive smoking) and analyzed by liquid chromatography-mass spectrometry (LC-MS) for nicotine and cotinine. Hair samples were divided into three groups, infants, passive smoker adults and active smoker adults, and into eight subgroups according to the degree of exposure. The limit of quantification (LOQ) was 0.1 ng/mg for nicotine and 0.05 ng/mg for cotinine. Mean recovery was 69.15% for nicotine and 72.08% for cotinine. The within- and between-day precision for cotinine and nicotine was calculated at different concentrations. Moreover, hair nicotine and cotinine concentrations were highly correlated among adult active smokers (R (2) = 0.710, p < 0.001), among adult nonsmokers exposed to secondhand smoke (SHS; R (2) = 0.729, p < 0.001) and among infants (R (2) = 0.538, p = 0.01). Among the infants exposed to SHS from both parents the noted correlations were even stronger (R (2) = 0.835, p = 0.02). The above results identify the use of hair samples as an effective method for assessing exposure to tobacco, with a high association between nicotine and cotinine especially among infants heavily exposed to SHS.


Assuntos
Poluentes Atmosféricos/análise , Cotinina/análise , Monitoramento Ambiental/métodos , Cabelo/química , Nicotina/análise , Poluição por Fumaça de Tabaco/análise , Adulto , Biomarcadores/análise , Cromatografia Líquida de Alta Pressão , Exposição Ambiental/análise , Feminino , Humanos , Lactente , Exposição por Inalação , Limite de Detecção , Masculino , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por Electrospray
17.
Hum Exp Toxicol ; 31(3): 266-73, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21427137

RESUMO

In the present paper, the possibility to use dialkyl phosphate metabolites (DAPs) hair segmental analysis as a biomarker of past acute exposure to organophosphates is examined. Hair samples of four acute poisoning survivors were collected and segmental hair analysis was performed. The total hair samples were divided to 1 cm segments and analysed by gas chromatography-mass spectrometry (GC-MS) for the presence of four DAP metabolites, dimethyl phosphate (DMP), diethyl phosphate (DEP), diethyl thiophosphate (DETP) and diethyl dithiophosphate (DEDTP). Results were examined under the light of pesticide type and time of hair sample collection. Although DAPs were detected all along the hair shaft, higher concentrations (peaks) were detected in the segments proximate to the suicide period. It was also observed that the elevated concentrations of the present metabolites corresponded to the ones produced by the ingested parent compound. Conclusively, measurements of DAPs in the appropriate hair segments of OP-poisoned patients can be used for assessing past acute exposure to organophosphates in certain cases.


Assuntos
Monitoramento Ambiental/métodos , Cabelo/metabolismo , Compostos Organofosforados/metabolismo , Praguicidas/metabolismo , Intoxicação/metabolismo , Adolescente , Adulto , Biomarcadores/análise , Biomarcadores/metabolismo , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Cabelo/química , Humanos , Intoxicação por Organofosfatos , Organofosfatos/análise , Organofosfatos/metabolismo , Compostos Organofosforados/análise , Praguicidas/análise , Praguicidas/intoxicação , Fosfatos/análise , Fosfatos/metabolismo , Intoxicação/etiologia , Intoxicação/terapia , Tentativa de Suicídio , Adulto Jovem
18.
Int J Mol Med ; 26(1): 85-94, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20514426

RESUMO

Novel amphiphilic poly-N-vinylpyrrolidone derivatives with different molecular weight of hydrophilic PVP fragment and one secondary di-n-alkyl terminal hydrophobic fragment of different length were synthesized to compare their inclination for formation of nano-scaled micelle-like aggregates in aqueous media with previously studied primary n-alkyl terminated poly-N-vinylpyrrolidones. The behavior of amphiphilies in water solutions was studied and critical aggregation concentration values for prepared polymer samples were determined by fluorescence spectroscopy and compared with those for primary n-alkyl derivatives. Polymeric micelle-like particles with or without encapsulated drug were prepared using dialysis or solvent evaporation techniques. Indomethacin was incorporated into hydrophobic inner core of these nanoparticles as a typical model drug. Dynamic light-scattering studies determined that the average size of particles formed was from 90 nm up to 600 nm with monodisperse size distribution and the nanoparticle size slightly increased with the amount of indomethacin encapsulated into inner core of the particles. In vitro release experiments carried out at different medium pH values using indomethacin-loaded nanoparticles exhibited slow and steady drug release into the medium.


Assuntos
Portadores de Fármacos/química , Indometacina/farmacocinética , Nanopartículas/química , Pirrolidinonas/química , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacocinética , Composição de Medicamentos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Indometacina/química , Cinética , Lipídeos/química , Microscopia Eletrônica de Transmissão , Nanopartículas/ultraestrutura , Tamanho da Partícula , Temperatura , Água/química
19.
J Chromatogr B Analyt Technol Biomed Life Sci ; 878(17-18): 1246-52, 2010 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-20226747

RESUMO

A new, simple, fast and sensitive method that enables the measurement of four dialkyl phosphates (DAPs) in human head hair is presented in the current study. The dialkyl phosphates, dimethyl phosphate (DMP), diethyl phosphate (DEP), diethyl thiophosphate (DETP) and diethyl dithiophosphate (DEDTP) are non-selective metabolites of the organophosphate pesticides (OPs). The extraction of DAPs from hair matrix was achieved by one step methanolic extraction. Head hair samples from general population and population occupationally exposed to OPs were analysed using gas chromatography-mass spectrometry (GC-MS) after derivatization with pentafluorobenzylbromide. The recovery of the target compounds was estimated at 84.3% for DMP, 116.1% for DEP, 109.0% for DETP and 91.5% for DEDTP. The limit of quantitation (LOQ) and detection (LOD) was 20 and 6 pg/mg for DMP, 10 and 5 pg/mg for DEP and DETP and 5 and 3 pg/mg for DEDTP, respectively. With-run and between-run precision as well as accuracy was estimated. The percentage of positive hair samples for DMP, DEP, DETP and DEDTP for the group of general population was 63.0%, 96.3%, 66.7%, and 70.4% respectively. The samples from the group with occupational exposure were positive for all dialkyl phosphates analysed. The median concentrations for DMP were 165.0 and 181.7 pg/mg, for DEP were 51.2 and 812.9 pg/mg, for DETP were 54.0 and 660.1 pg/mg, and for DEDTP were 40.0 and 60.6 pg/mg for the general population group and the group with occupational exposure respectively. Significant differences in the levels of the total dialkyl phosphates amongst exposed and not exposed groups were observed (p<0.001). More specifically, the total ethyl phosphate (DEPs) and DAPs median concentrations were 119.5 and 301.5 pg/mg for the general population group and 1498.8 and 1694.4 pg/mg for the group with occupational exposure.


Assuntos
Monitoramento Ambiental/métodos , Cabelo/química , Compostos Organofosforados/análise , Praguicidas/análise , Exposição Ambiental , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Modelos Lineares , Masculino , Compostos Organofosforados/química , Praguicidas/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Estatísticas não Paramétricas
20.
Hum Exp Toxicol ; 29(6): 459-66, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19939905

RESUMO

Exposure to secondhand smoke (SHS) is a significant threat to public health, and represents a danger for both the development and health status of children and adolescents. Taking the above into account, our aim was to quantify Greek adolescents' exposure to SHS using serum cotinine levels. During 2006, 341 adolescents aged 13-17 were randomly selected from high schools in Heraklion and agreed to participate as part of the European Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study. Blood samples were drawn from a random sample of 106 adolescents, while serum cotinine/nicotine concentrations were measured by Gas Chromatography-Mass Spectrometry (GC-MS). The mean levels of serum cotinine and nicotine were calculated at 1.60 +/- 2.18 ng/mL and 4.48 +/- 4.00 ng/mL, respectively, while 97.7% of the non-smoker adolescents were found to have measureable levels of serum cotinine indicating exposure to SHS. The analysis revealed that their paternal (p = .001) and maternal smoking habits (p = .018) as also the existence of a younger brother or sister (p = .008) were the main modifiers of SHS exposure during adolescence. Conclusively, almost all of the measured Greek adolescents were exposed to SHS, even when their parents were non-smokers. This finding indicates the need for both community and school-based educational programmes as also the implementation of a comprehensive ban on smoking in public places.


Assuntos
Cotinina/sangue , Exposição por Inalação/estatística & dados numéricos , Poluição por Fumaça de Tabaco/estatística & dados numéricos , Adolescente , Envelhecimento , Biomarcadores/sangue , Família , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Grécia , Inquéritos Epidemiológicos , Humanos , Exposição por Inalação/prevenção & controle , Masculino , Nicotina/sangue , Caracteres Sexuais , Poluição por Fumaça de Tabaco/prevenção & controle
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...