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We report on single- and double-charge photofragment formation by synchrotron radiation, following C 1s core excitation and ionization and Cl 2p inner excitation and ionization of chlorobenzene, C6H5Cl. From a comparison of experimental near-edge X-ray absorption fine structure spectra and theoretical ab initio calculations, the nature of various core and inner shell transitions of the molecule and pure atomic features were identified. To shed light on the normal Auger processes following excitation or ionization of the molecule at the Cl 2p or C 1s sites, we addressed the induced ionic species formation. With energy resolved electron spectra and ion time-of-flight spectra coincidence measurements, the ionic species were correlated with binding energy regions and initial states of vacancies. We explored the formation of the molecular dication C6H5Cl2+, the analogue benzene dication C6H42+, and the singly charged species produced by single loss of a carbon atom, C5HnCl+. The appearance and intensities of the spectral features associated with these ionic species are shown to be strongly site selective and dependent on the energy ranges of the Auger electron emission. Unexpected intensities for the analogue double charged benzene C6H42+ ion were observed with fast Auger electrons. The transitions leading to C6H5Cl2+ were identified from the binding energy representation of high resolution electron energy spectra. Most C6H5Cl2+ ions decay into two singly charged moieties, but intermediate channels are opened leading to other heavy dicationic species, C6H42+ and C6H4Cl2+, the channel leading to the first of these being much more favored than the other.
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Controlled or slow release fertilizers have been recommended to enhance crop yield, while minimizing environmental and economic issues related from current fertilizer applications. However, alternative biodegradable and non-toxic coating material should be suggested to produce biocoated fertilizers. Here we propose the use of lignin and poly(vinyl acetate) (PVAc) as biocoating materials for preparing slow release urea fertilizer. The blend of PVAc and lignin at a mass ratio of 75:25 improved the characteristics of the formed film and increased the nitrogen release time if compared to the pure polymers. The nitrogen release time from urea granules coated with a polymeric layer of 154.3⯱â¯5.5⯵m formed by lignin and PVAc was 36 times greater than from bare urea. The increase in the polymeric coating from 52.6⯱â¯5.2 to 80.2⯱â¯6.1⯵m decreased the curvature of the nitrogen release data by a factor of at least 1.7, while the curvature was decreased in at least 1.3 with the increase in the polymeric coating from 80.2⯱â¯6.1 to 158.9⯱â¯10.6⯵m. The adjustment of nitrogen release data to the Peppas-Sahlin model indicated the Fickian diffusion is more predominant than relaxation contributions, since the used polymers did not present considerable swelling. Thus, the blending of PVAc and lignin at 25â¯wt% of lignin and 75â¯wt% of PVAc is suggested as a biocoating material for producing slow release fertilizers.
Assuntos
Lignina/química , Nitrogênio/química , Polivinil/química , Composição de Medicamentos , Fertilizantes , Ureia/químicaRESUMO
OBJECTIVE: Schistosomiasis is a debilitating disease that affects 200 million people worldwide. Schistosoma haematobium and Schistosoma mansoni are the major causative agents of this disease. Cancer-association and infertility-association in Schistosoma haematobium infection have already been described and it is known that the parasite produces a catechol-estrogen molecule that induces a hormonal imbalance in the host. METHODS: In order to better understand the relation of hormonal imbalance in experimental Schistosoma mansoni infection, we investigated a serum panel of steroid hormones in Schistosoma mansoni infected hamsters. RESULTS: We found a decrease in the serum levels of Estradiol (E2), Testosterone and Progesterone in infected females and an increase of Testosterone and a decrease in Progesterone in infected males in comparison with controls. CONCLUSION: These results indicate that S. mansoni alters the levels of steroid hormones in infected males and females and it will increase the repertoire of data about the host-parasite molecular interplay and its relation with the endocrine system.
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Estradiol/sangue , Progesterona/sangue , Schistosoma mansoni/patogenicidade , Esquistossomose mansoni/sangue , Testosterona/sangue , Animais , Modelos Animais de Doenças , Regulação para Baixo , Feminino , Interações Hospedeiro-Parasita , Masculino , Mesocricetus , Esquistossomose mansoni/parasitologia , Fatores SexuaisRESUMO
Intravoxel Incoherent Motion (IVIM) is a recently rediscovered noninvasive magnetic resonance imaging (MRI) method based on diffusion-weighted imaging. It enables the separation of the intravoxel signal into diffusion due to Brownian motion and perfusion-related contributions and provides important information on microperfusion in the tissue and therefore it is a promising tool for applications in neurological and neurovascular diseases. This review focuses on the basic principles and outputs of IVIM and details it major applications in the brain, such as stroke, tumor, and cerebral small vessel disease. A bi-exponential model that considers two different compartments, namely capillaries, and medium-sized vessels, has been frequently used for the description of the IVIM signal and may be important in those clinical applications cited before. Moreover, the combination of IVIM and arterial spin labeling MRI enables the estimation of water permeability across the blood-brain barrier (BBB), suggesting a potential imaging biomarker for disrupted-BBB diseases.
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Neoplasias Encefálicas/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Transtornos Cerebrovasculares/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Acidente Vascular Cerebral/diagnóstico por imagem , Encéfalo/irrigação sanguínea , Encéfalo/patologia , Neoplasias Encefálicas/irrigação sanguínea , Neoplasias Encefálicas/patologia , Transtornos Cerebrovasculares/patologia , Humanos , Processamento de Imagem Assistida por Computador , Acidente Vascular Cerebral/patologiaRESUMO
Schizophrenia is a severe mental disorder that affects the anatomy and function of the brain, with an impact on one's thoughts, feelings, and behavior. The purpose of the study was to investigate cerebral blood flow (CBF) and brain connectivity in a group of patients with schizophrenia. Pseudo-continuous arterial spin labeling (pCASL) images were acquired from 28 patients in treatment and 28 age-matched healthy controls. Mean CBF and connectivity patterns were assessed. Schizophrenia patients had decreased CBF in the bilateral frontal pole and superior frontal gyrus, right medial frontal gyrus, triangular and opercular parts of the inferior frontal gyrus, posterior division of the left supramarginal gyrus, superior and inferior divisions of the left lateral occipital cortex, and bilateral occipital pole. Moreover, through different methods to assess connectivity, our results showed abnormal connectivity patterns in regions involved in motor, sensorial, and cognitive functions. Using pCASL, a non-invasive technique, we found CBF deficits and altered functional organization of the brain in schizophrenia patients that are associated with the symptoms and characteristics of the disorder.
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Circulação Cerebrovascular/fisiologia , Imageamento por Ressonância Magnética/métodos , Imagem de Perfusão/métodos , Esquizofrenia/fisiopatologia , Marcadores de Spin , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/fisiopatologia , Mapeamento Encefálico , Estudos de Casos e Controles , Cognição , Feminino , Humanos , Masculino , Esquizofrenia/diagnóstico por imagemRESUMO
BACKGROUND: Dominance of resistance has been one of the major parameters affecting the rate of evolution of resistance to Bt crops. High dose is the capacity of Bt crops to kill heterozygous insects and has been an essential component of the most successful strategy to manage resistance to these crops. Experiments were conducted to evaluate directly and indirectly whether the TC1507 event is high dose to Spodoptera frugiperda (JE Smith). RESULTS: About 8% of heterozygote neonate larvae were able to survive, complete larval development and emerge as normal adults on TC1507 leaves, while susceptible larvae could not survive for 5 days. The estimated dominance of resistance was 0.15 ± 0.09 and significantly higher than zero; therefore, the resistance to Cry1F expressed in TC1507 was not completely recessive. A 25-fold dilution of TC1507 maize leaf tissue in an artificial diet was able to cause a maximum mortality of only 37%, with growth inhibition of 82% at 7 days after larval infestation. CONCLUSION: Resistance to Cry1F in TC1507 maize is incompletely recessive in S. frugiperda. TC1507 maize is not high dose for S. frugiperda. Additional or alternative resistance management strategies, such as the replacement of single-trait Bt maize with pyramided Bt maize, which produces multiple proteins targeting the same insect pests, should be implemented wherever this technology is in use and S. frugiperda is the major pest.
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Proteínas de Bactérias/farmacologia , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia , Resistência a Inseticidas , Inseticidas/farmacologia , Spodoptera/efeitos dos fármacos , Zea mays/genética , Animais , Toxinas de Bacillus thuringiensis , Brasil , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Plantas Geneticamente Modificadas/genética , Spodoptera/crescimento & desenvolvimentoRESUMO
INTRODUCTION: Early carotid revascularization (≤ 14 days) is recommended for symptomatic carotid stenosis. Carotid artery stenting (CAS) has become an alternative to carotid endarterectomy (CEA); however, safety data on early CAS is controversial. The study aims to compare early versus late CAS, when CAS is performed as a first intention revascularization strategy. METHODS: A retrospective analysis of all symptomatic patients admitted to our stroke unit who underwent CAS was conducted. Patients were divided between two groups: patients who had undergone CAS within 14 days after symptoms and those who had undergone CAS later. Primary endpoints were ipsilateral ischemic stroke or ipsilateral parenchymal hemorrhage (iPH) at 30 days. The secondary endpoints were major adverse cardiac and cerebrovascular events (MACCE) at the 30-day and at the 12-month follow-up. RESULTS: One hundred twenty-seven consecutive patients were evaluated. Primary endpoints obtained in the early and late CAS groups were, respectively, ipsilateral stroke (2.0% vs. 2.6%, P = 1.00) and iPH (2.0% vs. 0.0%, P = 0.40). The rates of MACCE between the early and the late CAS groups were, respectively, (7.8% vs. 2.6%, P = 0.21) at the 30-day follow-up, and (12.2% vs. 10.5%, P = 0.77) at the 12-month follow-up. CONCLUSIONS: In this study, CAS seems to be safe when used as first intention revascularization treatment within 2 weeks of symptoms, if infarcted area is less than one third of the middle cerebral artery territory. Our results need to be confirmed by larger studies.
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Angioplastia com Balão/métodos , Estenose das Carótidas/cirurgia , Endarterectomia das Carótidas , Stents , Adulto , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/etiologia , Isquemia Encefálica/cirurgia , Estenose das Carótidas/complicações , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Medição de Risco , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/cirurgia , Fatores de Tempo , Resultado do TratamentoRESUMO
Impaired cerebrovascular reactivity (CVR), a predictive factor of imminent stroke, has been shown to be associated with carotid steno-occlusive disease. Magnetic resonance imaging (MRI) techniques, such as blood oxygenation level-dependent (BOLD) and arterial spin labeling (ASL), have emerged as promising noninvasive tools to evaluate altered CVR with whole-brain coverage, when combined with a vasoactive stimulus, such as respiratory task or injection of acetazolamide. Under normal cerebrovascular conditions, CVR has been shown to be globally and homogenously distributed between hemispheres, but with differences among cerebral regions. Such differences can be explained by anatomical specificities and different biochemical mechanisms responsible for vascular regulation. In patients with carotid steno-occlusive disease, studies have shown that MRI techniques can detect impaired CVR in brain tissue supplied by the affected artery. Moreover, resulting CVR estimations have been well correlated to those obtained with more established techniques, indicating that BOLD and ASL are robust and reliable methods to assess CVR in patients with cerebrovascular diseases. Therefore, the present paper aims to review recent studies which use BOLD and ASL to evaluate CVR, in healthy individuals and in patients with carotid steno-occlusive disease, providing a source of information regarding the obtained results and the methodological difficulties.
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Organophosphorus-induced delayed neuropathy (OPIDN) is a neurodegenerative disorder characterised by ataxia progressing to paralysis with concomitant central and peripheral distal axonopathy. Symptoms of OPIDN in people include tingling of the hands and feet. This tingling is followed by sensory loss, progressive muscle weakness and flaccidity of the distal skeletal muscles of the lower and upper extremities and ataxia, which appear about 8-14 days after exposure. Some organophosphorus compounds (OPs) that are still used in worldwide agriculture have potential to induce OPIDN, including methamidophos, trichlorfon, dichlorvos and chorpyrifos. This review summarizes experimental attempts to prevent and/or treat OPIDN and the different mechanisms involved in each approach. The initial mechanism associated with development of OPIDN is phosphorylation and inhibition of neuropathy target esterase (NTE). The phosphorylated enzyme undergoes a second reaction known as "aging" that results in the loss of one of the "R" groups bound to the phosphorus of the OP. A second mechanism involved in OPIDN is an imbalance in calcium homeostasis. This can lead to the activation of calcium-activated neutral protease and increases in calcium/calmodulin-dependent protein kinases. These events contribute to aberrant phosphorylation of cytoskeletal proteins and protein digestion in the terminal axon that can proceed similarly to Wallerian-type degeneration. Several experimental studies demonstrated alleviation of the signs and symptoms of OPIDN by restoring calcium balance. Other studies have used preadministration of NTE inhibitors, such as carbamates, thiocarbamates, sulfonyl fluorides and phosphinate to prevent OPIDN. Progress is being made, but there is yet no single specific treatment available for use in clinical practice to prevent or alleviate the severe effects of OPIDN.
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Síndromes Neurotóxicas/etiologia , Síndromes Neurotóxicas/prevenção & controle , Compostos Organofosforados/toxicidade , Animais , Cálcio/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Hidrolases de Éster Carboxílico/antagonistas & inibidores , Hidrolases de Éster Carboxílico/metabolismo , Homeostase/efeitos dos fármacos , Humanos , Síndromes Neurotóxicas/terapia , Fosforilação/efeitos dos fármacos , Degeneração Walleriana/induzido quimicamente , Degeneração Walleriana/metabolismoRESUMO
BACKGROUND: Obstructive sleep apnea (OSA) is related to increased systemic inflammation and arterial hypertension. We hypothesize that OSA is frequent in patients with acute hypertensive intracerebral hemorrhage (ICH) and is related to the perihematoma edema. METHODS: Thirty-two non-comatose patients with a hypertensive ICH underwent polysomnography in the acute phase. Perihematoma edema volume was measured on CT scans at admission, after 24 h (early control) and after 4-5 days (late control). The Spearman coefficient (r(s)) was used for correlations. RESULTS: OSA occurred in 19 (59.4%) patients. The apnea-hypopnea index was correlated with relative edema at admission CT (r(s) = 0.40; p = 0.031), early CT (r(s) = 0.46; p = 0.011) and at late CT (r(s) = 0.59; p = 0.006). CONCLUSIONS: OSA is highly frequent during the acute phase of hypertensive ICH and is related to perihematoma edema.
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Edema Encefálico/etiologia , Hematoma/etiologia , Hemorragia Intracraniana Hipertensiva/complicações , Apneia Obstrutiva do Sono/etiologia , Doença Aguda , Idoso , Edema Encefálico/diagnóstico por imagem , Feminino , Hematoma/diagnóstico por imagem , Humanos , Hemorragia Intracraniana Hipertensiva/diagnóstico por imagem , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Polissonografia , Estudos Prospectivos , Medição de Risco , Fatores de Risco , Índice de Gravidade de Doença , Apneia Obstrutiva do Sono/diagnóstico , Fatores de Tempo , Tomografia Computadorizada por Raios XRESUMO
Monocrotaline is a pyrrolizidine alkaloid present in plants of the Crotalaria species, which causes cytotoxicity and genotoxicity, including hepatotoxicity in animals and humans. It is metabolized by cytochrome P-450 in the liver to the alkylating agent dehydromonocrotaline. We evaluated the effects of monocrotaline and its metabolite on respiration, membrane potential and ATP levels in isolated rat liver mitochondria, and on respiratory chain complex I NADH oxidase activity in submitochondrial particles. Dehydromonocrotaline, but not the parent compound, showed a concentration-dependent inhibition of glutamate/malate-supported state 3 respiration (respiratory chain complex I), but did not affect succinate-supported respiration (complex II). Only dehydromonocrotaline dissipated mitochondrial membrane potential, depleted ATP, and inhibited complex I NADH oxidase activity (IC50=62.06 microM) through a non-competitive type of inhibition (K(I)=8.1 microM). Therefore, dehydromonocrotaline is an inhibitor of the activity of respiratory chain complex I NADH oxidase, an action potentially accounting for the well-documented monocrotaline's hepatotoxicity to animals and humans. The mechanism probably involves change of the complex I conformation resulting from modification of cysteine thiol groups by the metabolite.
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Alquilantes/farmacologia , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Complexo I de Transporte de Elétrons/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Mitocôndrias Hepáticas/efeitos dos fármacos , Monocrotalina/análogos & derivados , Trifosfato de Adenosina/metabolismo , Animais , Doença Hepática Induzida por Substâncias e Drogas/enzimologia , Relação Dose-Resposta a Droga , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias Hepáticas/enzimologia , Monocrotalina/farmacologia , Complexos Multienzimáticos/metabolismo , NADH NADPH Oxirredutases/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , Ratos , Ratos Wistar , Partículas Submitocôndricas/efeitos dos fármacos , Partículas Submitocôndricas/enzimologiaRESUMO
UV radiation-induced skin damages may result in pre-cancerous and cancerous skin lesions, and acceleration of skin aging. It involves an imbalance of the endogenous antioxidant system that leads to the increase of free radical levels and inflammation. Therefore, antioxidant supplementation might inhibit such imbalance. In this regard, quercetin is a promising drug, this plant derived lipophilic flavonoid presents the higher antioxidant activity among flavonoids and multiple antioxidant mechanisms. Thus, the present study investigated the possible beneficial effects of topical formulations containing quercetin to inhibit UVB irradiation-induced oxidative damages. Quercetin was administered on the dorsal skin of hairless mice using two formulations, formulation 1 (non-ionic emulsion with high lipid content) and formulation 2 (anionic emulsion with low lipid content). The UVB irradiation (0.31-3.69 J/cm(2)) induced a dose-dependent increase in the myeloperoxidase (MPO) activity (4-2708%) and depletion of reduced glutathione (GSH) (22-68%) in the skin of hairless mice after 6h. These results demonstrated that the UVB doses are not excessive, and additionally, they are lower than the doses used in other similar studies. Proteinases secretion/activity, detected by the qualitative sodium dodecyl sulphate polyacrylamide gel electrophoresis substrate-embedded enzymography (zymography), was also enhanced in the same manner as MPO activity using the UVB dose of 1.23J /cm(2). Formulations 1 and 2 inhibited the MPO activity increase (62% and 59%, respectively), GSH depletion (119% and 53%, respectively) and proteinases secretion/activity. To our knowledge, this is the first study to demonstrate the effectiveness of topical formulations containing quercetin to inhibit the UVB irradiation-induced skin damages. Thus, these data suggest the possible usefulness of topical formulations containing quercetin to prevent UVB radiation skin damages.