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1.
Environ Geochem Health ; 43(7): 2781-2798, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33576940

RESUMO

In this work, we report metals concentrations in 80 PM10 samples collected at four sites in the Mexico City Metropolitan Area (MCMA): Tlalnepantla (NE), Xalostoc (NE), Merced (C), and Pedregal (S), during the dry/cold season (October to January) for the 2004-2014 period. Mean PM10 mass concentration (66.1 µg m-3) significantly exceeds the annual mean air quality guidelines recommended by the World Health Organization. The statistical analysis of concentration data and meteorological parameters allows us to recognize the importance of wind intensity speed (Wsp) and wind direction conditions in the enrichment of PM concentrations. The proximity and magnitude of the emitting source is also relevant for PM concentration. Such conditions favored that higher metal concentration was recognized at the north of the studied area. By means principal component analysis (PCA) was difficult to identify the groups of metals associated with specific sources (anthropogenic and geogenic) given the high complexity of the study area and the long period of time evaluated. Metal concentration trend shows an important positive trend for Pt, V and Cr, while PM10, Ni, Cu, Ag and Sb show a trend of moderate increase. In contrast, Pb and Co registered a strong percentage reduction, while Hg, Mn, As and Cd show a slight reduction, probably resulting from the implementation of regulatory measures and influenced by urban changes associated at the north of the studied area. The results of this research provide information that should be considered for evaluating the impact of anthropogenic sources and applying regulatory measures to control emissions.


Assuntos
Poluentes Atmosféricos/análise , Metais Pesados/análise , Metais/análise , Material Particulado/análise , Poluição do Ar/análise , Cidades , Monitoramento Ambiental/métodos , México , Estações do Ano , Vento
2.
Bull Environ Contam Toxicol ; 107(3): 514-518, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34245312

RESUMO

This paper presents atmospheric gaseous elemental mercury (GEM) data recorded during two short-term monitoring surveys in the Mexico City Metropolitan Area (MCMA) at 12th May 2019 and at 22nd May 2020, during conditions of low and high human activity respectively. Results, although they are limited, can be considered as the representative range of exposure to GEM of the inhabitants of MCMA; differences in results reveal the impact of human activities on GEM background levels (2.53 and 3.76 ng m-3, respectively). GEM concentrations and their spatial distribution does not allow for the identification of important industrial sources and do not reach intervention pollution levels. The activity of the Popocatépetl volcano is not likely to have an effect on GEM in the MCMA. In spite the evident decrease in GEM concentrations compared with data previously reported, monitoring must be carried out routinely given Mexico's participation in the Minamata Convention on Mercury.


Assuntos
Poluentes Atmosféricos , Mercúrio , Poluentes Atmosféricos/análise , Cidades , Monitoramento Ambiental , Humanos , Mercúrio/análise , México
3.
Apoptosis ; 22(3): 421-436, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27943067

RESUMO

Cell cytoskeleton makes profound changes during apoptosis including the organization of an Apoptotic Microtubule Network (AMN). AMN forms a cortical structure which plays an important role in preserving plasma membrane integrity during apoptosis. Here, we examined the cytoskeleton rearrangements during apoptosis induced by camptothecin (CPT), a topoisomerase I inhibitor, in human H460 and porcine LLCPK-1α cells. Using fixed and living cell imaging, we showed that CPT induced two dose- and cell cycle-dependent types of apoptosis characterized by different cytoskeleton reorganizations, time-dependent caspase activation and final apoptotic cell morphology. In the one referred as "slow" (~h) or round-shaped, apoptosis was characterized by a slow contraction of the actinomyosin ring and late caspase activation. In "slow" apoptosis the γ-tubulin complexes were not disorganized and microtubules were not depolymerized at early stages. In contrast, "fast" (~min) or irregular-shaped apoptosis was characterized by early caspase activation followed by full contraction of the actinomyosin ring. In fast apoptosis γ-tubulin complexes were disorganized and microtubules were initially depolymerized. However, after actinomyosin contraction, microtubules were reformed adopting a cortical but irregular disposition near plasma membrane. In addition to distinctive cytoskeleton reorganization kinetics, round and irregular-shaped apoptosis showed different biological properties with respect to AMN maintenance, plasma membrane integrity and phagocytes response. Our results suggest that the knowledge and modulation of the type of apoptosis promoted by genotoxic agents may be important for deciding a better therapeutic option and predicting the immune response in cancer treatment.


Assuntos
Apoptose/fisiologia , Camptotecina/farmacologia , Citoesqueleto/efeitos dos fármacos , Dano ao DNA , Inibidores da Topoisomerase I/farmacologia , Actomiosina/metabolismo , Animais , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Forma Celular , Citoesqueleto/fisiologia , Relação Dose-Resposta a Droga , Ativação Enzimática , Humanos , Células LLC-PK1 , Microtúbulos/efeitos dos fármacos , Microtúbulos/ultraestrutura , Fagocitose/efeitos dos fármacos , Suínos , Tubulina (Proteína)/efeitos dos fármacos
4.
Int J Mol Sci ; 18(11)2017 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-29137119

RESUMO

During apoptosis, cells undergo characteristic morphological changes in which the cytoskeleton plays an active role. The cytoskeleton rearrangements have been mainly attributed to actinomyosin ring contraction, while microtubule and intermediate filaments are depolymerized at early stages of apoptosis. However, recent results have shown that microtubules are reorganized during the execution phase of apoptosis forming an apoptotic microtubule network (AMN). Evidence suggests that AMN is required to maintain plasma membrane integrity and cell morphology during the execution phase of apoptosis. The new "two coffins" hypothesis proposes that both AMN and apoptotic cells can adopt two morphological patterns, round or irregular, which result from different cytoskeleton kinetic reorganization during the execution phase of apoptosis induced by genotoxic agents. In addition, round and irregular-shaped apoptosis showed different biological properties with respect to AMN maintenance, plasma membrane integrity and phagocyte responses. These findings suggest that knowing the type of apoptosis may be important to predict how fast apoptotic cells undergo secondary necrosis and the subsequent immune response. From a pathological point of view, round-shaped apoptosis can be seen as a physiological and controlled type of apoptosis, while irregular-shaped apoptosis can be considered as a pathological type of cell death closer to necrosis.


Assuntos
Apoptose , Citoesqueleto/metabolismo , Modelos Biológicos , Dano ao DNA , Humanos , Microtúbulos/metabolismo , Transdução de Sinais
5.
Apoptosis ; 19(9): 1364-77, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25027509

RESUMO

Apoptotic microtubule network (AMN) is organized during apoptosis, forming a cortical structure beneath the plasma membrane which plays a critical role in preserving cell morphology and plasma membrane integrity. The aim of this study was to examine the effect of cold/warming exposure on apoptotic microtubules and plasma membrane integrity during the execution phase of apoptosis. We demonstrated in camptothecin-induced apoptotic H460 cells that cold/warming exposure disorganized apoptotic microtubules and allowed the access of active caspases to the cellular cortex and the cleavage of essential proteins in the preservation of plasma membrane permeability. Cleavage of cellular cortex and plasma membrane proteins, such as α-spectrin, paxilin, focal adhesion kinase and calcium ATPase pump (PMCA-4) involved in cell calcium extrusion resulted in increased plasma permeability and calcium overload leading apoptotic cells to secondary necrosis. The essential role of caspase-mediated cleavage in this process was demonstrated because the addition of the pan-caspase inhibitor z-VAD during cold/warming exposure that induces AMN depolymerization avoided the cleavage of cortical and plasma membrane proteins and prevented apoptotic cells to undergo secondary necrosis. Likewise, apoptotic microtubules stabilization by taxol during cold/warming exposure also prevented cellular cortex and plasma membrane protein cleavage and secondary necrosis. Furthermore, microtubules stabilization or caspase inhibition during cold/warming exposure was also critical for proper phosphatidylserine externalization and apoptotic cell clearance by macrophages. These results indicate that cold/warming exposure of apoptotic cells induces secondary necrosis which can be prevented by both, microtubule stabilization or caspase inhibition.


Assuntos
Apoptose , Temperatura Baixa , Temperatura Alta , Microtúbulos/ultraestrutura , Antineoplásicos Fitogênicos/farmacologia , Cálcio/metabolismo , Camptotecina/farmacologia , Caspases/metabolismo , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Humanos , Macrófagos/metabolismo , Proteínas de Membrana/metabolismo , Microtúbulos/efeitos dos fármacos , Necrose , Oligopeptídeos/farmacologia , Paclitaxel/farmacologia , Fosfatidilserinas/metabolismo
6.
Life (Basel) ; 13(1)2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36676078

RESUMO

Although diverse fossil angiosperms (including their reproductive organs) have been reported from the Early Cretaceous, few of them are well-documented due to poor preservation and limited technologies available to apply. For example, paraffin sectioning, a routine technology applied to reveal the anatomical details of extant plants, was hitherto at most rarely applied to fossil plants. This undermines the comparability between the outcomes of studies on fossil and extant plants, and makes our understanding on plants incomplete and biased. Here, we applied paraffin sectioning technology, in addition to light microscopy, SEM, and TEM, to document a fossil reproductive organ, Xilinia gen. nov., from the Early Cretaceous in Inner Mongolia, China. The anatomical details of this new reproductive organ were documented. Xilinia bears a remarkable resemblance to conifer cones, although its ovules are enclosed in carpels. The paradoxical cone-like morphology of Xilinia appears to represent a transitional snapshot of plant evolution that is absent in extant plants.

7.
Sci Rep ; 13(1): 426, 2023 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-36624144

RESUMO

The Early Jurassic angiosperm Nanjinganthus has triggered a heated debate among botanists, partially due to the fact that the enclosed ovules were visible to naked eyes only when the ovary is broken but not visible when the closed ovary is intact. Although traditional technologies cannot confirm the existence of ovules in a closed ovary, newly available Micro-CT can non-destructively reveal internal features of fossil plants. Here, we performed Micro-CT observations on three dimensionally preserved coalified compressions of Nanjinganthus. Our outcomes corroborate the conclusion given by Fu et al., namely, that Nanjinganthus is an Early Jurassic angiosperm.


Assuntos
Magnoliopsida , Ovário , Óvulo Vegetal , Genitália Feminina , Ovário/diagnóstico por imagem , Microtomografia por Raio-X
8.
FASEB J ; 25(8): 2669-87, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21551238

RESUMO

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) is a mitochondrial disease most usually caused by point mutations in tRNA genes encoded by mtDNA. Here, we report on how this mutation affects mitochondrial function in primary fibroblast cultures established from 2 patients with MELAS who harbored the A3243G mutation. Both mitochondrial respiratory chain enzyme activities and coenzyme Q(10) (CoQ) levels were significantly decreased in MELAS fibroblasts. A similar decrease in mitochondrial membrane potential was found in intact MELAS fibroblasts. Mitochondrial dysfunction was associated with increased oxidative stress and the activation of mitochondrial permeability transition (MPT), which triggered the degradation of impaired mitochondria. Furthermore, we found defective autophagosome elimination in MELAS fibroblasts. Electron and fluorescence microscopy studies confirmed a massive degradation of mitochondria and accumulation of autophagosomes, suggesting mitophagy activation and deficient autophagic flux. Transmitochondrial cybrids harboring the A3243G mutation also showed CoQ deficiency and increased autophagy activity. All these abnormalities were partially restored by CoQ supplementation. Autophagy in MELAS fibroblasts was also abolished by treatment with antioxidants or cyclosporine, suggesting that both reactive oxygen species and MPT participate in this process. Furthermore, prevention of autophagy in MELAS fibroblasts resulted in apoptotic cell death, suggesting a protective role of autophagy in MELAS fibroblasts.


Assuntos
Síndrome MELAS/metabolismo , Síndrome MELAS/patologia , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Ubiquinona/análogos & derivados , Autofagia/genética , Autofagia/fisiologia , Proteína 5 Relacionada à Autofagia , Sequência de Bases , Células Cultivadas , Primers do DNA/genética , DNA Mitocondrial/genética , Transporte de Elétrons , Fibroblastos/metabolismo , Fibroblastos/patologia , Técnicas de Silenciamento de Genes , Humanos , Síndrome MELAS/genética , Proteínas Associadas aos Microtúbulos/antagonistas & inibidores , Proteínas Associadas aos Microtúbulos/genética , Mitocôndrias/genética , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Poro de Transição de Permeabilidade Mitocondrial , Mutação Puntual , RNA Interferente Pequeno/genética , RNA de Transferência de Leucina/genética , Espécies Reativas de Oxigênio/metabolismo , Ubiquinona/deficiência
9.
Arch Latinoam Nutr ; 62(2): 179-84, 2012 Jun.
Artigo em Espanhol | MEDLINE | ID: mdl-23610906

RESUMO

The appearance of rice grain is a key aspect in quality determination. Mainly, this analysis is performed by expert analysts through visual observation; however, due to the subjective nature of the analysis, the results may vary among analysts. In order to evaluate the concordance between analysts from Latin-American rice quality laboratories for rice grain appearance through digital images, an inter-laboratory test was performed with ten analysts and images of 90 grains captured with a high resolution scanner. Rice grains were classified in four categories including translucent, chalky, white belly, and damaged grain. Data was categorized using statistic parameters like mode and its frequency, the relative concordance, and the reproducibility parameter kappa. Additionally, a referential image gallery of typical grain for each category was constructed based on mode frequency. Results showed a Kappa value of 0.49, corresponding to a moderate reproducibility, attributable to subjectivity in the visual analysis of grain images. These results reveal the need for standardize the evaluation criteria among analysts to improve the confidence of the determination of rice grain appearance.


Assuntos
Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Laboratórios/normas , Oryza/anatomia & histologia , Humanos , América Latina , Variações Dependentes do Observador , Controle de Qualidade , Especificidade da Espécie , Estatística como Assunto/métodos
10.
Antibiotics (Basel) ; 11(8)2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-36009993

RESUMO

Outpatient parenteral antimicrobial therapy (OPAT) programs encompass a range of healthcare processes aiming to treat infections at home, with the preferential use of the intravenous route. Although several barriers arise during the implementation of OPAT circuits, recent cumulative data have supported the effectiveness of these programs, demonstrating their application in a safe and cost-effective manner. Given that OPAT is evolving towards treating patients with higher complexity, a multidisciplinary team including physicians, pharmacists, and nursing staff should lead the program. The professionals involved require previous experience in infectious diseases treatment as well as in outpatient healthcare and self-administration. As we describe here, clinical pharmacists exert a key role in OPAT multidisciplinary teams. Their intervention is essential to optimize antimicrobial prescriptions through their participation in stewardship programs as well as to closely follow patients from a pharmacotherapeutic perspective. Moreover, pharmacists provide specialized counseling on antimicrobial treatment technical compounding. In fact, OPAT elaboration in sterile environments and pharmacy department clean rooms increases OPAT stability and safety, enhancing the quality of the program. In summary, building multidisciplinary teams with the involvement of clinical pharmacists improves the management of home-treated infections, promoting a safe self-administration and increasing OPAT patients' quality of life.

12.
Genes (Basel) ; 12(11)2021 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-34828374

RESUMO

Genetic variants in the apolipoprotein E (APOE) gene are associated with lipid metabolism and lipid-related traits in the non-Hispanic population. There have been limited studies regarding the association between the APOE gene and hypercholesterolemia in the Hispanic population; therefore, our aim for this study is to examine the APOE gene's associations with cholesterol level and its related phenotypes. The APOE gene consists of three different alleles, ε2, ε3, and ε4, with ε4 being associated with dementia and cardiovascular diseases. A total of 1,382 subjects were collected from the Texas Alzheimer's Research and Care Consortium (TARCC, N = 1320) and the Initial Study of Longevity and Dementia from the Rio Grande Valley (ISLD-RGV, N = 62). Questionnaires on demographics, medical history, and blood/saliva samples were collected and APOE genotypes were performed. We observed allele frequencies of the APOE ε3 (96.7%), ε4 (22.6%) and ε2 (6.8%) alleles, respectively. Multivariable logistic regression revealed a significant association between the APOE ε4 allele and hypercholesteremia (p = 1.8 × 10-4) in our studied Hispanic population. We prove for the first time, that the APOE ε4 allele increases the risk for hypercholesterol in Hispanics. Further research is needed to confirm and supports our current findings.


Assuntos
Apolipoproteínas E/genética , Predisposição Genética para Doença/etnologia , Hispânico ou Latino/genética , Hipercolesterolemia/genética , Polimorfismo de Nucleotídeo Único , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Frequência do Gene , Genótipo , Humanos , Hipercolesterolemia/etnologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Fenótipo
13.
Dalton Trans ; 50(7): 2510-2520, 2021 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-33514974

RESUMO

Based on the determination of single crystal XRD structures of potassium hexacyanidometallates and on IR, and Raman data, here we propose for the first time the occurrence of an electron-deficient bonding between the N end of the CN- ligand and the K+ metal center. The crystal structures of Kn[M6-n(CN)6]·xH2O (M = Fe(ii), Ru(ii), Os(ii), Co(iii), Rh(iii), Ir(iii), Pt(iv)) reveal the presence of four types of CN-K interactions: (i) a linear CN-K bond, (ii) the N ends in a bipodal coordination involving two K atoms, (iii) the N ends in a tripodal coordination mode involving three K atoms and (iv) the N ends and the K atoms with the largest K-N distances within the subseries that can be attributed to the electrostatic interactions. The bi- and tripodal coordination modes between the N end of the CN- ligand and K+ ions are atypical and their nature is discussed in this contribution. The CN- ligand N end can behave as a two-electron donor that participates in a three-center two-electron bonding (i.e. Class II µ-L 3c-2e) for a N-bipodal coordination mode or as a two-electron donor that participates in a four-center two-electron bonding (4c-2e) for an N-tripodal coordination mode. Such a possibility is closely related to the π-back donation ability of the CN- ligand, which results in a charge density accumulation on the N end, which could be partially donated to the K atom through an σ-mechanism. For the divalent metals (Fe, Ru, Os), the solids crystallize with a monoclinic unit cell in the C2/c space group, while for the trivalent ones (Co, Rh, Ir), the crystal structure corresponds to an orthorhombic unit cell in the Pbcn space group. Potassium hexacyanidoplatinate(iv) crystallizes with a trigonal unit cell, in the P3[combining macron]1m space group, where each N end is always found coordinating two K atoms. The finding of these novel coordination modes of the CN- ligands, relying on an electron-deficient bonding behavior, paves the way for the design of functional materials based on hexacyanidometallates. The experimental results and the proposed electron-deficient bonding model herein discussed were appropriately supported by the computational calculations.

14.
Environ Res ; 110(5): 443-7, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19733843

RESUMO

Mice exposed to sodium arsenite show a dose-related accumulation of inorganic arsenic (iAs) and its methylated metabolites in the liver. While the accumulation of iAs forms increased linearly with dose in liver cells, a different pattern was observed in other tissues such as the brain and lung, as well as in the peripheral nerves of the rat. As such, trivalent iAs enters the cells, using aquaglyceroporin transporters to modulate cell arsenic accumulation and cytotoxicity. We investigated here if the dose-related accumulation of arsenic in the liver was related to the expression of aquaglyceroporin 9 (AQP9) in the same organ. CD1 male mice were treated with different concentrations (0, 2.5, 5 or 10mg/kg/day) of sodium arsenite during 1, 3 or 9 days. A significant dose-related, up-regulation of AQP9 mRNA and protein was observed and which was verified by immunohistochemistry in liver sections using specific antibodies. The increased transcription of AQP9 has been observed in fasting and diabetic rats, suggesting that this channel could play a role in the diabetogenic effect of arsenic.


Assuntos
Aquagliceroporinas/metabolismo , Aquaporinas/metabolismo , Arsenitos/toxicidade , Fígado/efeitos dos fármacos , Compostos de Sódio/toxicidade , Animais , Arsenitos/administração & dosagem , Arsenitos/metabolismo , Relação Dose-Resposta a Droga , Glicerol/metabolismo , Fígado/metabolismo , Masculino , Camundongos , Compostos de Sódio/administração & dosagem , Compostos de Sódio/metabolismo , Ureia/metabolismo
15.
Arch Latinoam Nutr ; 60(4): 397-404, 2010 Dec.
Artigo em Espanhol | MEDLINE | ID: mdl-21866691

RESUMO

In Venezuela, white corn is the most important crop regarding production, harvest area and consumption. One of its main by-products is corn oil, whose positive effect on health caused by the high content of unsaturated fatty acids has been widely recognized. In order to characterize the fatty acids profile of twelve white grained maize hybrids extensively grown in Venezuela, and the effect that divergent localities has on this profile, three semi commercial scale trials where established in Portuguesa, Yaracuy and Guárico states. Proportions of the main fatty acids in the raw oil of the different grain samples were determined using gas chromatography. Significant differences (p < 0,01) between hybrids were found for arachidic, palmitic, stearic, oleic, gadoleic and linoleic acids; non significant differences were found for linolenic acid. Significant differences between localities were found for all the fatty acids evaluated. High and significant correlations between fatty acids content were found; the most important relations were: linoleic-oleic (Rho = -0,98**), arachidic-palmitic (Rho = -0,61**), linoleic-stearic (Rho = -0,61**) and oleic-stearic (Rho = 0,58**). Corn produced in Venezuela presents lower levels of linoleic and higher levels of palmitic, stearic and oleic acids than the levels found in temperate corn. These differences involve significant changes in the nutritional properties of Venezuelan corn oil that should be considered in the development of new cultivars and industrial processes for oil production.


Assuntos
Quimera , Ácidos Graxos Insaturados/análise , Óleos de Plantas/química , Zea mays/química , Cromatografia Gasosa , Venezuela , Zea mays/classificação
16.
Toxicol Appl Pharmacol ; 235(3): 329-37, 2009 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-19263520

RESUMO

Since amitriptyline is a very frequently prescribed antidepressant drug, it is not surprising that amitriptyline toxicity is relatively common. Amitriptyline toxic systemic effects include cardiovascular, autonomous nervous, and central nervous systems. To understand the mechanisms of amitriptyline toxicity we studied the cytotoxic effects of amitriptyline treatment on cultured primary human fibroblasts and zebrafish embryos, and the protective role of coenzyme Q(10) and alpha-tocopherol, two membrane antioxidants. We found that amitriptyline treatment induced oxidative stress and mitochondrial dysfunction in primary human fibroblasts. Mitochondrial dysfunction in amitriptyline treatment was characterized by reduced expression levels of mitochondrial proteins and coenzyme Q(10), decreased NADH:cytochrome c reductase activity, and a drop in mitochondrial membrane potential. Moreover, and as a consequence of these toxic effects, amitriptyline treatment induced a significant increase in apoptotic cell death activating mitochondrial permeability transition. Coenzyme Q(10) and alpha-tocopherol supplementation attenuated ROS production, lipid peroxidation, mitochondrial dysfunction, and cell death, suggesting that oxidative stress affecting cell membrane components is involved in amitriptyline cytotoxicity. Furthermore, amitriptyline-dependent toxicity and antioxidant protection were also evaluated in zebrafish embryos, a well established vertebrate model to study developmental toxicity. Amitriptyline significantly increased embryonic cell death and apoptosis rate, and both antioxidants provided a significant protection against amitriptyline embryotoxicity.


Assuntos
Amitriptilina/antagonistas & inibidores , Amitriptilina/toxicidade , Ubiquinona/análogos & derivados , alfa-Tocoferol/farmacologia , Animais , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Embrião não Mamífero/citologia , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Fibroblastos/patologia , Humanos , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Ubiquinona/farmacologia , Peixe-Zebra/embriologia
17.
Chemosphere ; 72(11): 1807-15, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18541287

RESUMO

The competitive sorption of 1,2-cis-dichloroethene (cis-DCE) and trichloroethene (TCE) was investigated by means of column experiments using a model porous mineral solid represented by silica gel. The experimental isotherms were obtained by employing a chromatographic method. The competitive sorption isotherms were modelled with the extended Freundlich and extended Langmuir isotherms, using the parameters from single-solute experiments. The breakthrough curves were modelled with the advection-dispersion transport equation coupled with the lumped pore diffusion model. The best results were obtained when the extended Freundlich isotherm was employed. The competitive sorption was revealed with the presence of an overshoot in the breakthrough curve of cis-DCE and a decrease in the degree of sorption of cis-DCE (20%) and TCE (12%). A linear dependency of the overshoot with an increase in the concentration of cis-DCE at a fixed concentration of TCE was observed, between 16% and 20%, and at least at concentrations <6 mg L(-1) in the liquid phase. The displaced molecules of cis-DCE by TCE were accumulated through the column causing its overshoot; thus short columns may hinder its observation. Thermodynamic analysis shows an exothermic adsorption process of -34 to -41 kJ mol(-1), which is enhanced by sorption in micropores. The Gibbs free energy is positive for cis-DCE in the multi-component case, due to its displacement by TCE.


Assuntos
Dicloroetilenos/química , Minerais/química , Dióxido de Silício/química , Tricloroetileno/química , Adsorção , Sílica Gel
18.
BMC Complement Altern Med ; 8: 12, 2008 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-18410686

RESUMO

BACKGROUND: Migraine is a chronic neurologic disease that can severely affect the patient's quality of life. Although in recent years many randomised studies have been carried out to investigate the effectiveness of acupuncture as a treatment for migraine, it remains a controversial issue. Our aim is to determine whether acupuncture, applied under real conditions of clinical practice in the area of primary healthcare, is more effective than conventional treatment. METHODS/DESIGN: The design consists of a pragmatic multi-centre, three-armed randomised controlled trial, complemented with an economic evaluation of the results achieved, comparing the effectiveness of verum acupuncture with sham acupuncture, and with a control group receiving normal care only. Patients eligible for inclusion will be those presenting in general practice with migraine and for whom their General Practitioner (GP) is considering referral for acupuncture. Sampling will be by consecutive selection, and by randomised allocation to the three branches of the study, in a centralised way following a 1:1:1 distribution (verum acupuncture; sham acupuncture; conventional treatment). Secondly, one patient in three will be randomly selected from each of the acupuncture (verum or sham) groups for a brain perfusion study (by single photon emission tomography). The treatment with verum acupuncture will consist of 8 treatment sessions, once a week, at points selected individually by the acupuncturist. The sham acupuncture group will receive 8 sessions, one per week, with treatment being applied at non-acupuncture points in the dorsal and lumbar regions, using the minimal puncture technique. The control group will be given conventional treatment, as will the other two groups. DISCUSSION: This trial will contribute to available evidence on acupuncture for the treatment of migraine. The primary endpoint is the difference in the number of days with migraine among the three groups, between the baseline period (the 4 weeks prior to the start of treatment) and the period from weeks 9 to 12. As a secondary aspect, we shall record the index of laterality and the percentage of change in the mean count per pixel in each region of interest measured by the brain perfusion tomography, performed on a subsample of the patients within the real and sham acupuncture groups. TRIAL REGISTRATION: Current Controlled Trials ISRCTN98703707.


Assuntos
Terapia por Acupuntura/métodos , Transtornos de Enxaqueca/terapia , Atenção Primária à Saúde/métodos , Projetos de Pesquisa , Adulto , Método Duplo-Cego , Feminino , Humanos , Masculino , Efeito Placebo , Qualidade de Vida , Espanha , Resultado do Tratamento
19.
PLoS One ; 13(5): e0196393, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29763446

RESUMO

Silicon-diode-based detectors are commonly used for the dosimetry of small radiotherapy beams due to their relatively small volumes and high sensitivity to ionizing radiation. Nevertheless, silicon-diode-based detectors tend to over-respond in small fields because of their high density relative to water. For that reason, detector-specific beam correction factors ([Formula: see text]) have been recommended not only to correct the total scatter factors but also to correct the tissue maximum and off-axis ratios. However, the application of [Formula: see text] to in-depth and off-axis locations has not been studied. The goal of this work is to address the impact of the correction factors on the calculated dose distribution in static non-conventional photon beams (specifically, in stereotactic radiosurgery with circular collimators). To achieve this goal, the total scatter factors, tissue maximum, and off-axis ratios were measured with a stereotactic field diode for 4.0-, 10.0-, and 20.0-mm circular collimators. The irradiation was performed with a Novalis® linear accelerator using a 6-MV photon beam. The detector-specific correction factors were calculated and applied to the experimental dosimetry data for in-depth and off-axis locations. The corrected and uncorrected dosimetry data were used to commission a treatment planning system for radiosurgery planning. Various plans were calculated with simulated lesions using the uncorrected and corrected dosimetry. The resulting dose calculations were compared using the gamma index test with several criteria. The results of this work presented important conclusions for the use of detector-specific beam correction factors ([Formula: see text] in a treatment planning system. The use of [Formula: see text] for total scatter factors has an important impact on monitor unit calculation. On the contrary, the use of [Formula: see text] for tissue-maximum and off-axis ratios has not an important impact on the dose distribution calculation by the treatment planning system. This conclusion is only valid for the combination of treatment planning system, detector, and correction factors used in this work; however, this technique can be applied to other treatment planning systems, detectors, and correction factors.


Assuntos
Radiocirurgia/estatística & dados numéricos , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Simulação por Computador , Humanos , Modelos Estatísticos , Método de Monte Carlo , Fótons/uso terapêutico , Radiometria/estatística & dados numéricos , Dosagem Radioterapêutica , Espalhamento de Radiação , Silicones
20.
Elife ; 72018 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-30558712

RESUMO

The origin of angiosperms has been a long-standing botanical debate. The great diversity of angiosperms in the Early Cretaceous makes the Jurassic a promising period in which to anticipate the origins of the angiosperms. Here, based on observations of 264 specimens of 198 individual flowers preserved on 34 slabs in various states and orientations, from the South Xiangshan Formation (Early Jurassic) of China, we describe a fossil flower, Nanjinganthus dendrostyla gen. et sp. nov.. The large number of specimens and various preservations allow for an evidence-based reconstruction of the flower. From the evidence of the combination of an invaginated receptacle and ovarian roof, we infer that the seeds of Nanjinganthus were completely enclosed. Evidence of an actinomorphic flower with a dendroid style, cup-form receptacle, and angiospermy, is consistent with Nanjinganthus being a bona fide angiosperm from the Jurassic, an inference that we hope will re-invigorate research into angiosperm origins.


Assuntos
Evolução Biológica , Flores/anatomia & histologia , Flores/classificação , Fósseis , Magnoliopsida/classificação , China , Magnoliopsida/anatomia & histologia
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