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1.
Med Sci Monit Basic Res ; 29: e938849, 2023 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-36883230

RESUMO

BACKGROUND Postoperative tracheal extubation requires optimal timing to ensure patient safety and normal muscle function. The train-of-four ratio (TOFR) of the fourth muscle response compared with the first indicates a non-depolarizing neuromuscular block, and a ratio ≥0.9 can be used as an objective measurement of neuromuscular reversal. This study of 60 adult patients who underwent elective surgery with general anesthesia that included the neuromuscular blocking agent cisatracurium aimed to compare standard postoperative clinical assessment with the TOFR ≥0.9 on patient outcomes using postoperative neuromuscular function assessed by grip strength and ability to sit up unaided and spirometry measurements following extubation. MATERIAL AND METHODS The 30 patients extubated postoperatively in the TOF group were required to have a TOFR ≥0.9, while the 30 patients in the clinical assessment group were awake and following simple commands and had a 5-second head lift and spontaneous breathing with acceptable oxygenation. The main outcomes were the incentive spirometry and grip strength and ability to sit up unaided measured at 10, 30, 50 min and 24 h after extubation. RESULTS The groups had no difference in recovery path of incentive spirometry volume (P=0.072) and no difference in postoperative incentive spirometry decrease from baseline except at 10 min after extubation (P=0.005). There was no difference in handgrip strength and independent sitting between groups. CONCLUSIONS The findings showed that using the TOF ratio ≥0.9 before extubation did not improve early postoperative strength quantified by spirometry volume, handgrip strength, and proportion of unaided sitting.


Assuntos
Extubação , Força da Mão , Humanos , Adulto , Espirometria
2.
Artigo em Inglês | MEDLINE | ID: mdl-36078511

RESUMO

China's goal of becoming a strong agricultural country cannot be achieved without the modernization and digital transformation of the agricultural sector. Presently, China's agriculture has ushered in the era of digital economy transformation. The digital transformation of agriculture has played a huge role in improving agricultural productivity, promoting sustainable development of China's agricultural economy, and achieving sustainable development goals. The deep integration of digital economy and agricultural economy has become an important issue of The Times. This study uses a two-way fixed-effects model and an instrumental variable method to examine the impact of environmental regulation on agricultural total factor productivity. Using the method of mechanism analysis, the conduction path of improving agricultural productivity under the means of environmental regulation is discussed. Therefore, the visualization analysis results based on the panel data of Chinese agricultural enterprises from 2011 to 2019 show that the distribution of digital transformation and productivity level of enterprises is uneven and tends to be stable in space. The empirical analysis results show that there is a direct and significant positive relationship between voluntary environmental regulation and agricultural total factor productivity. The results of mechanism analysis show that, under the means of environmental regulation, digital transformation plays an indirect role in improving agricultural productivity. On the basis of enriching and deepening the theoretical extension of the "Porter Hypothesis", this study subtly incorporates environmental regulation, digital transformation, and agricultural productivity into a unified framework, expanding existing research.


Assuntos
Agricultura , Eficiência , China , Desenvolvimento Econômico , Desenvolvimento Sustentável
3.
J Neurosurg Spine ; : 1-6, 2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35523252

RESUMO

OBJECTIVE: The authors investigated a new standardized technique for evaluating lumbar stability in lumbar lateral flexion-extension (LFE) radiographs. For patients with lumbar spondylolisthesis, a three-part fulcrum with a support platform that included a semiarc leaning tool with armrests, a lifting platform for height adjustment, and a base for stability were used. Standard functional radiographs were used for comparison to determine whether adequate flexion-extension was acquired through use of the fulcrum method. METHODS: A total of 67 consecutive patients diagnosed with L4-5 degenerative lumbar spondylolisthesis were enrolled in the study. The authors analyzed LFE radiographs taken with the patient supported by a fulcrum (LFEF) and without a fulcrum. Sagittal translation (ST), segmental angulation (SA), posterior opening (PO), change in lumbar lordosis (CLL), and lumbar instability (LI) were measured for comparison using functional radiographs. RESULTS: The average value of SA was 5.76° ± 3.72° in LFE and 9.96° ± 4.00° in LFEF radiographs, with a significant difference between them (p < 0.05). ST and PO were also significantly greater in LFEF than in LFE. The detection rate of instability was 10.4% in LFE and 31.3% in LFEF, and the difference was significant. The CLL was 27.31° ± 11.96° in LFE and 37.07° ± 12.963.16° in LFEF, with a significant difference between these values (p < 0.05). CONCLUSIONS: Compared with traditional LFE radiographs, the LFEF radiographs significantly improved the detection rate of LI. In addition, this method may reduce patient discomfort during the process of obtaining radiographs.

4.
J Agric Food Chem ; 70(8): 2712-2721, 2022 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-35142511

RESUMO

The enantioselective toxicity of triticonazole (TRZ) to non-target organisms, the effect on wheat growth and quality, and the environmental fate of TRZ were investigated systematically in this study. The acute toxicity of S-TRZ to non-target aquatic and terrestrial organisms was greater than that of rac-TRZ and R-TRZ. The S-enantiomer significantly inhibited the growth and lodging resistance of wheat. S- and R-TRZ not only reduced the grain yield but also inhibited the activities of ADP-glucose pyrophosphorylase (AGPase) and starch synthase. The results of homology modeling and molecular docking further showed that the inhibition of AGPase activity by the two enantiomers hindered the accumulation of starch. By contrast, the racemate promoted the growth and development of wheat and improved grain quality. And the half-lives of the racemate in stems, grains, leaves, and soils were shorter than those of the enantiomers. The results of risk quotient (RQ) values showed that the application of TRZ enantiomers during wheat planting would bring a higher potential dietary risk to Chinese consumers. In comprehensive consideration of these results, the application of the racemate may be safer and more reasonable at the flowering stage of wheat.


Assuntos
Fungicidas Industriais , Ciclopentanos , Fungicidas Industriais/toxicidade , Simulação de Acoplamento Molecular , Medição de Risco , Estereoisomerismo , Triazóis
5.
Waste Manag ; 139: 330-340, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-35007953

RESUMO

The environmental risk assessment and the factors influencing heavy metals (HM) in the soil at the municipal solid waste landfill sites (MSWLs) were studied by literature review, field survey, and statistical methods. The results indicated that the dominant HM contamination in the soil at the MSWLs was caused by chromium (Cr) with the Nemero index values (PI) from 22.7 to 44.3 and zinc (Zn) with the PI from 0.7 to 9.8. There were significant differences in the Cr, mercury (Hg), lead (Pb), Zn, and arsenic (As) concentrations between soil samples from sanitary and non-sanitary landfills (NSLs) where HM contamination (PI = 10.9) was more obvious. As (CRAAs = 2.35 × 10-4) and cadmium (Cd) (CRACd = 1.45 × 10-4) posed potential carcinogenic health effects. The soil Cd concentration had a significant negative correlation (r = -0.476**) with the landfill age. The soil As concentration had a significant positive correlation (r = 0.472**) with rainfall in NSLs. There were significant differences in the As (P = 0.042) and copper (Cu) (P = 0.042) concentrations between soil samples from the surrounding areas of MSWLs and the base where soil had higher HM concentrations. For the efficient prevention of HM ecological risk, a scientific site selection, undamaged coverage and anti-seepage systems, standardized management, and ongoing monitoring are required.


Assuntos
Metais Pesados , Poluentes do Solo , China , Monitoramento Ambiental , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análise , Resíduos Sólidos/análise , Instalações de Eliminação de Resíduos
6.
J Vis Exp ; (177)2021 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-34842229

RESUMO

Energy expenditure measurements are necessary to understand how changes in metabolism can lead to obesity. Basal energy expenditure can be determined in mice by measuring whole-body oxygen consumption, CO2 production, and physical activity using metabolic cages. Thermogenic brown/beige adipocytes (BA) contribute significantly to rodent energy expenditure, particularly at low ambient temperatures. Here, measurements of basal energy expenditure and total BA capacity to expend energy in obese mice are described in two detailed protocols: the first explaining how to set up the assay to measure basal energy expenditure using analysis of covariance (ANCOVA), a necessary analysis given that energy expenditure co-varies with body mass. The second protocol describes how to measure BA energy expenditure capacity in vivo in mice. This procedure involves anesthesia, needed to limit expenditure caused by physical activity, followed by the injection of beta3-adrenergic agonist, CL-316,243, which activates energy expenditure in BA. These two protocols and their limitations are described in sufficient detail to allow a successful first experiment.


Assuntos
Adipócitos Marrons , Termogênese , Adipócitos Marrons/metabolismo , Tecido Adiposo Marrom/metabolismo , Animais , Metabolismo Energético , Camundongos , Camundongos Obesos , Obesidade/metabolismo , Termogênese/fisiologia
7.
Comput Intell Neurosci ; 2021: 8865816, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34113377

RESUMO

An accurate prediction of stock market index is important for investors to reduce financial risk. Although quite a number of deep learning methods have been developed for the stock prediction, some fundamental problems, such as weak generalization ability and overfitting in training, need to be solved. In this paper, a new deep learning model named Random Long Short-Term Memory (RLSTM) is proposed to get a better predicting result. RLSTM includes prediction module, prevention module, and three full connection layers. Input of the prediction module is a stock or an index which needs to be predicted. That of the prevention module is a random number series. With the index of Shanghai Securities Composite Index (SSEC) and Standard & Poor's 500 (S&P500), simulations show that the proposed RLSTM can mitigate the overfitting and outperform others in accuracy of prediction.


Assuntos
Investimentos em Saúde , Memória de Longo Prazo , China
8.
J Hazard Mater ; 414: 125492, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-33647613

RESUMO

Ethiprole is effective against a wide range of insects and has been used throughout the world. In this work, the toxicity, bioaccumulation and elimination of ethiprole and its main metabolites (ethiprole sulfone (M1), ethiprole sulfide (M2), ethiprole amide (M3), ethiprole sulfone amide (M4) and desethylsulfinyl ethiprole (M5)) in zebrafish Danio rerio were investigated at enantiomeric level. Rac-ethiprole showed high toxicity (96 h LC50 = 708 µg L-1) and M2 was six times more toxic than ethiprole (111 µg L-1). Enantioselective toxicity was observed, with the S-ethiprole (924 µg L-1) being more toxic than R-ethiprole (2195 µg·L-1). Rac-ethiprole and M2 could induce oxidative stress in the liver of adult zebrafish and developmental toxicity in zebrafish embryos. Zebrafish were exposed to 100 µg L-1 rac-/R-/S-ethiprole and the bioaccumulation was monitored during a 21 d period followed by a 7 d metabolism. The bioconcentration factor (BCF) of rac-ethiprole was 17, and the half-lives of rac-ethiprole and metabolites varied between 0.44 and 2.99 d. R-ethiprole was preferentially accumulated and metabolized in zebrafish. Besides, the metabolic pathways of R- and S-ethiprole were found to be different. This study indicated assessment of metabolites and enantioselectivity should be taken into consideration in evaluating environmental risks of ethiprole.


Assuntos
Pirazóis , Peixe-Zebra , Animais , Bioacumulação , Estereoisomerismo
9.
Environ Pollut ; 269: 116139, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33307394

RESUMO

The residue of simazine herbicide in the environment is known as one of pollutant stress for lizards by crippling its fitness on direct toxic effects and indirect food shortage via the food chain effects. Both stressors were considered in our experiment in the simazine exposure and food availability to lizards (Eremias argus). The results revealed that starvation significantly reduced the lizard's energy reserve and native immune function, while the accumulation of simazine in the liver was significantly increased. Simazine caused oxidative stress in the liver of lizards, but oxidative damage only occurred in the starved lizards. Simazine also changed the energy reserves, native immune function and detoxification of well-fed lizards, while the starved lizards showed different sensitivity to simazine. Simazine or starvation treatment independently activated the lizard HPA axis, but co-treatment caused the HPA axis inhibition. Besides, according to the variations on amino acid neurotransmitters, corticosterone hormone and thermoregulatory behavior, we inferred that lizards in threatens take the appropriate strategy on energy investment and allocation through neural, endocrine and behavioral pathways to maximize benefits in dilemma. Energy allocation was necessary, while suppression on any physiological process comes at a cost that is detrimental to long-term individual fitness.


Assuntos
Lagartos , Animais , Privação de Alimentos , Sistema Hipotálamo-Hipofisário , Masculino , Sistema Hipófise-Suprarrenal , Simazina
10.
Environ Int ; 137: 105490, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32007685

RESUMO

The ecological and health risk assessment of environmental pesticide residues have attracted ever-growing attention; however, their transformation products (TPs) have seldom been considered. Herein, we examined the endocrine-disrupting effects of 4 widely used pesticides as pyriproxyfen (Pyr), malathion (ML), benalaxyl (BX), and fenoxaprop-ethyl (FE), together with their 21 TPs through in vitro and in silico approaches, and found approximately 50% of the TPs exhibited stronger endocrine-disrupting effects than their corresponding parent compounds. Specifically, Pyr and 9 TPs (five TPs of Pyr, one of ML, one of BX, and two of FE) exhibited estrogen-disrupting effects, which were also confirmed by results of E-screen and pS2 expression assays, and molecular docking showed that certain hydroxylated TPs could well mimic the binding mode of estrogen with ERα. Meanwhile, two TPs of Pyr, ML and its TP demonstrated weak glucocorticoid antagonistic activities partially contributed by hydrogen bonds. We also discovered that in H295R cells, all the endocrine disruptors increased hormone secretion and the related gene expression levels. Conclusively, since an increasing number of pesticide TPs have been being detected in various environmental media, a more comprehensive understanding of the ecological risk of pesticide TPs is imperative for risk assessments more extensively and regulatory policy-making on pesticide restriction in the future.


Assuntos
Disruptores Endócrinos , Resíduos de Praguicidas , Praguicidas , Disruptores Endócrinos/toxicidade , Simulação de Acoplamento Molecular , Resíduos de Praguicidas/toxicidade , Praguicidas/toxicidade , Medição de Risco
11.
J Hazard Mater ; 389: 121835, 2020 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-31843398

RESUMO

Pyriproxyfen (PYR) is a type of aromatic juvenile hormone analog and a hygienic insecticide used in agriculture to control insect species. Therefore, assessing the metabolic behavior and toxic effects of PYR in mammals is the best means of evaluating its risks to human health. Previous studies have reported conflicting results regarding the toxicity risks of PYR and its metabolites in rat hepatocytes. We used ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to perform a chiral analysis of PYR and its metabolites investigating the enantioselective metabolism of PYR in rat liver microsomes. Our results concluded that the recoveries of PYR, metabolites A and B ranged from 81.13%-111.54 %, with RSD values of 0.01 %-6.52 %. The method limits of detection (LODs) and limits of quantification (LOQs) for PYR, metabolites A and B were in accordance with the analysis requirements. Previous studies have demonstrated the enantioselective metabolism of PYR and the generation of metabolites. Measurements of cell proliferation toxicity to rat hepatocytes, apoptosis and DNA damage induced by PYR and its metabolites in rat hepatocytes indicated that the metabolites reflected higher toxicity potential than PYR in rat hepatocytes. More studies about the molecular mechanism of PYR-induced toxicity are urgently needed in future work.


Assuntos
Dano ao DNA , Hepatócitos/efeitos dos fármacos , Inseticidas/toxicidade , Microssomos Hepáticos/efeitos dos fármacos , Piridinas/toxicidade , Animais , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Hepatócitos/metabolismo , Hepatócitos/patologia , Técnicas In Vitro , Inseticidas/química , Limite de Detecção , Masculino , Microssomos Hepáticos/metabolismo , Microssomos Hepáticos/patologia , Estrutura Molecular , Piridinas/química , Ratos , Ratos Sprague-Dawley , Medição de Risco
12.
Chirality ; 31(6): 468-475, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31066960

RESUMO

Chiral fungicide prothioconazole has a wide range of antifungal spectrum; however, little research has been conducted to evaluate prothioconazole on an enantiomeric level. Five target pathogens and three common aquatic organisms were tested for the enantioselective bioactivity and toxicity of prothioconazole in this work. The antifungal activity of the enantiomers against wheat phytoalexin, rice blast fungus, exserohilum turcicum, Alternaria triticina, and Fusarium avenaceum was determined, and it was found that (-)-prothioconazole were 85 to 2768 times more active than (+)-prothioconazole toward these target organisms. In order to reflect the risk to aquatic ecosystem, the acute toxicity of the enantiomers to Daphnia magna, Chlorella pyrenoidosa, and Lemna minor L. was assessed. It was observed that the toxicity of (-)-prothioconazole to D. magna was 2.2 times higher than (+)-prothioconazole, but it was lower to C. pyrenoidosa and L. minor L. The toxicities of (+)-enantiomer and (-)-enantiomer to D. magna and C. pyrenoidosa were synergy, indicating that the racemate had higher threat to the organisms. It could be concluded that the effects of prothioconazole on target organisms and the acute toxicity to nontarget species were enantioselective with (-)-enantiomer possessing higher efficiency and lower toxicity. Such enantiomeric differences should be taken into consideration when assessing the performance of prothioconazole.


Assuntos
Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Triazóis/química , Triazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Alternaria/efeitos dos fármacos , Animais , Ascomicetos/efeitos dos fármacos , Chlorella/efeitos dos fármacos , Daphnia/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Fungicidas Industriais/toxicidade , Fusarium/efeitos dos fármacos , Magnaporthe/efeitos dos fármacos , Doenças das Plantas/microbiologia , Estereoisomerismo , Testes de Toxicidade Aguda , Triazóis/farmacologia , Poluentes Químicos da Água/química
13.
Ecotoxicol Environ Saf ; 171: 657-664, 2019 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-30658301

RESUMO

Pesticides are proposed as one of the many causes for the global decline in reptile population. To understand the potential impact of alpha-cypermethrin (ACP) in reptiles, in the current study, we used a tri-trophic food web (plants - herbivores - natural enemies of predators) to examine the reproductive toxicity and biomarker changes. Based on the Maximum Residue Limit (MRL) of ACP in several agricultural products, we designed three concentrations 0, 2 (MRL), and 20 mg/kg wet weight as three treatment groups for this research. Male and female lizards were fed ACP contaminated or uncontaminated diets for eight weeks during the breeding phase. The number of deaths was different among the three groups, and a dose-dependent trend was found. Decreases in food consumption of 26.6% and 28.1% were observed in the low- and high-dose group, respectively. Dietary exposure significantly induced a dose-dependent decrease in body mass index in lizards. Significant variations in glutathione-S-transferaseb activities, catalase activities, and malondialdehyde levels in gonads, suggest that lizards were under oxidative stress. In addition, ACP exposure altered sexual hormone levels in males, reduced reproductive output of females, and induced histopathological changes in testes. These negative effects highlight that ACP dietary exposure is a potential threat to lizards' reproduction.


Assuntos
Dieta/veterinária , Lagartos , Praguicidas/toxicidade , Piretrinas/toxicidade , Reprodução/efeitos dos fármacos , Animais , Biomarcadores/sangue , Catalase/sangue , Relação Dose-Resposta a Droga , Ecologia , Estradiol/sangue , Feminino , Masculino , Malondialdeído/sangue , Estresse Oxidativo/efeitos dos fármacos , Medição de Risco , Superóxido Dismutase/sangue , Tenebrio , Testículo/efeitos dos fármacos , Testosterona/sangue
14.
Chemosphere ; 191: 373-380, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29054078

RESUMO

In this study, the metabolic responses of mice after 30 days of exposure to benalaxyl were assessed using NMR-based untargeted metabolomics and LC-MS-based targeted profiling of 20 amino acids. Urinary 1H NMR analyses revealed alterations in energy metabolism, lipid metabolism, vitamin B metabolism, the urea cycle and amino acid metabolism, and targeted analyses indicated that the serum levels of asparagine, histidine, lysine and aspartic acid were significantly altered. Additionally, significant oxidative stress was observed in the liver and kidney, although no apparent histopathological injury was observed. The tissue distribution indicated a significant stereoselectivity in the brain, where (-)-R-benalaxyl was enriched. These data provide a comprehensive picture of the subacute toxic effects of benalaxyl in mice. The results of this study suggested that, for a toxicity evaluation, metabolomics analysis is much more sensitive than traditional toxicological methods. The results also highlight the combined use of untargeted and targeted metabolomics approaches in evaluating the health risks of xenobiotics.


Assuntos
Alanina/análogos & derivados , Metabolômica/métodos , Alanina/farmacocinética , Alanina/toxicidade , Animais , Encéfalo/metabolismo , Cromatografia Líquida , Metabolismo Energético/efeitos dos fármacos , Rim/metabolismo , Metabolismo dos Lipídeos , Fígado/metabolismo , Espectroscopia de Ressonância Magnética/métodos , Espectrometria de Massas , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Distribuição Tecidual , Urinálise
15.
Sci Rep ; 7(1): 2288, 2017 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-28536421

RESUMO

Microcosms containing DDT spiked-sediment, Tubifex tubifex and carp (Cyprinus carpio) were constructed to simulate a freshwater system. The accumulation, elimination and toxic effects of DDT (p,p'-DDT, o,p'-DDT), and its metabolites DDD (p,p'-DDD, o,p'-DDD) and DDE (p,p'-DDE, o,p'-DDE) were studied in T. tubifex and carp. Tissue/organ distributions of DDTs were also investigated in carp. The bioaccumulation and elimination of DDT differed in T. tubifex, carp and its tissues/organs. Unimodal or bimodal distributions were observed, and the concentrations of DDT metabolites (DDD and p,p'-DDE) increased over time. The carp organ with the highest concentrations of DDTs (DDT, DDD and DDE) was the gill. The largest mass distribution of DDTs was also in gill, followed by muscle and gastrointestinal tract. Maximum levels of DDTs in whole carp and carp muscle were 161 and 87 ng/g, respectively; therefore, the levels of DDTs observed in carp in this study were insufficient to constitute a health concern if present in fish for human consumption. Significant changes were observed in some biomarkers, including superoxide dismutase, catalase, glutathione-S-transferase, glutathione, and carboxylesterase, in T. tubifex and carp tissues during DDT exposure. Tissue-specific accumulation of DDTs in carp can be a key indicator of exposure to environmentally relevant concentrations.


Assuntos
Carpas/metabolismo , DDT/metabolismo , Cadeia Alimentar , Poluentes Químicos da Água/metabolismo , Animais , Biotransformação , DDT/toxicidade , Água Doce , Trato Gastrointestinal/metabolismo , Brânquias/metabolismo , Músculos/metabolismo , Oligoquetos/efeitos dos fármacos , Oligoquetos/metabolismo , Alimentos Marinhos/análise , Poluentes Químicos da Água/toxicidade
16.
Environ Sci Pollut Res Int ; 24(4): 3618-3625, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27882496

RESUMO

Efficacy and potential environmental risks should be considered when applying enantiopure pesticides. In this study, Tubifex tubifex and its oxidative stress biomarkers were assessed for the toxicity of metalaxyl and metalaxyl-M in sediment. The toxicity assessment was conducted with artificial sediment and reconstituted water. Five test concentrations (from 0 to 100 mg/kg) were set for the short-term (4 days) exposure. The long-term (28 days) exposure was conducted with the environmental concentration (from 0.5 to 5 mg/kg). For the short-term exposure, the increase of superoxide dismutase (SOD) activity was observed, and a clear concentration-response relationship was found in the metalaxyl treatments. The decrease of catalase (CAT) and glutathione peroxidase (GPx) activity could be caused by oxidative stress. The decrease of glutathione (GSH) content and the increase of glutathione-S-transferase (GST) might be due to antioxidation defense and detoxification mechanisms. The increase of malondialdehyde (MDA) might be due to the saturation of antioxidant systems and the accumulation and toxicity of contaminations. In the long-term exposure, the changes of biomarkers in T. tubifex reflected the oxidative stress and detoxification metabolisms. GSH and the related enzymes were important in detoxification processes and involved in the oxidative stress in toxicity mechanism. The long-term direct contact bioassay is sensitive and appropriate to reflect the lower concentration of contaminants.


Assuntos
Metais/farmacologia , Oligoquetos/efeitos dos fármacos , Oligoquetos/metabolismo , Animais , Biomarcadores/metabolismo , Estresse Oxidativo/efeitos dos fármacos
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