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1.
Nature ; 599(7885): 436-441, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34732894

RESUMO

The state of somatic energy stores in metazoans is communicated to the brain, which regulates key aspects of behaviour, growth, nutrient partitioning and development1. The central melanocortin system acts through melanocortin 4 receptor (MC4R) to control appetite, food intake and energy expenditure2. Here we present evidence that MC3R regulates the timing of sexual maturation, the rate of linear growth and the accrual of lean mass, which are all energy-sensitive processes. We found that humans who carry loss-of-function mutations in MC3R, including a rare homozygote individual, have a later onset of puberty. Consistent with previous findings in mice, they also had reduced linear growth, lean mass and circulating levels of IGF1. Mice lacking Mc3r had delayed sexual maturation and an insensitivity of reproductive cycle length to nutritional perturbation. The expression of Mc3r is enriched in hypothalamic neurons that control reproduction and growth, and expression increases during postnatal development in a manner that is consistent with a role in the regulation of sexual maturation. These findings suggest a bifurcating model of nutrient sensing by the central melanocortin pathway with signalling through MC4R controlling the acquisition and retention of calories, whereas signalling through MC3R primarily regulates the disposition of calories into growth, lean mass and the timing of sexual maturation.


Assuntos
Desenvolvimento Infantil/fisiologia , Estado Nutricional/fisiologia , Puberdade/fisiologia , Receptor Tipo 3 de Melanocortina/metabolismo , Maturidade Sexual/fisiologia , Adolescente , Idoso de 80 Anos ou mais , Animais , Criança , Ciclo Estral/genética , Ciclo Estral/fisiologia , Feminino , Homozigoto , Humanos , Hipotálamo/citologia , Hipotálamo/fisiologia , Fator de Crescimento Insulin-Like I/metabolismo , Masculino , Melanocortinas/metabolismo , Menarca/genética , Menarca/fisiologia , Camundongos , Fenótipo , Puberdade/genética , Receptor Tipo 3 de Melanocortina/deficiência , Receptor Tipo 3 de Melanocortina/genética , Maturidade Sexual/genética , Fatores de Tempo , Aumento de Peso
2.
Occup Med (Lond) ; 74(3): 218-224, 2024 05 09.
Artigo em Inglês | MEDLINE | ID: mdl-38527057

RESUMO

BACKGROUND: Occupational footwear is intended to provide protection against the risks associated with work activities. The choice of footwear is complex due to the welfare, health and safety conditions of workers. AIMS: To identify the injuries and problems caused by occupational footwear through a systematic review of the existing literature. METHODS: A literature search was carried out in the Cumulative Index to Nursing and Allied Health Literature, Dialnet Plus, Pubmed, Scientific Electronic Library Online, Medline, Scopus and Web of Science databases over the period 2000-23, following the PRISMA Declaration guidelines. RESULTS: A total of 27 studies were included in the review. The results indicated that there is a wide variety of injuries caused by occupational footwear: from dermal injuries (e.g. calluses) and injuries to the nail apparatus to inflammatory pathologies such as plantar fasciitis or bursitis. In addition, inappropriate footwear can cause pain in the ankle and foot, knees, hips and lower back. Other results include the discomfort derived from the footwear itself. CONCLUSIONS: Inappropriate footwear can cause injuries to the foot and other related bone structures. Further studies are needed on the detection of foot injuries caused by occupational footwear and the levels of action at this level to improve the worker's health, the adaptability of the footwear to the wearer, and the worker's comfort and adherence to the footwear.


Assuntos
Traumatismos Ocupacionais , Sapatos , Humanos , Bursite/etiologia , Fasciíte Plantar/etiologia , Traumatismos do Pé/etiologia , Doenças Profissionais/etiologia , Traumatismos Ocupacionais/etiologia , Sapatos/efeitos adversos
3.
Eur Phys J E Soft Matter ; 46(12): 118, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38051443

RESUMO

We report here the spontaneous formation of lipid-bilayer-wrapped virus particles, following the injection of "naked" virus particles into the subphase of a Langmuir trough with a liquid monolayer of lipids at its air-water interface. The virus particles are those of the well-studied cowpea chlorotic mottle virus, CCMV, which are negatively charged at the pH 6 of the subphase; the lipids are a 9:1 mix of neutral DMPC and cationic CTAB molecules. Before adding CCMV particles to the subphase we establish the mixed lipid monolayer in its liquid-expanded state at a fixed pressure (17.5 mN/m) and average area-per-molecule of (41Å2). Keeping the total area fixed, the surface pressure is observed to decrease at about 15 h after adding the virus particles in the subphase; by 37 h it has dropped to zero, corresponding to essentially all the lipid molecules having been removed from the air-water interface. By collecting particles from the subphase and measuring their sizes by atomic force microscopy, we show that the virus particles have been wrapped by lipid bilayers (or by two lipid bilayers). These results can be understood in terms of thermal fluctuations and electrostatic interactions driving the wrapping of the anionic virus particles by the cationic lipids. Spontaneous acquisition by a virus particle of, first, a hydrophobic lipid monolayer envelope and, then, a hydrophilic lipid bilayer envelope, as it interacts from the subphase with an oppositely charged Langmuir monolayer.


Assuntos
Bicamadas Lipídicas , Fosfolipídeos , Bicamadas Lipídicas/química , Fosfolipídeos/química , Água/química , Propriedades de Superfície
4.
Am J Physiol Cell Physiol ; 323(6): C1791-C1806, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36342159

RESUMO

Iron absorption is a complex and highly controlled process where DMT1 transports nonheme iron through the brush-border membrane of enterocytes to the cytoplasm but does not transport alkaline-earth metals such as calcium. However, it has been proposed that high concentrations of calcium in the diet could reduce iron bioavailability. In this work, we investigate the effect of intracellular and extracellular calcium on iron uptake by Caco-2 cells, as determined by calcein fluorescence quenching. We found that extracellular calcium inhibits iron uptake by Caco-2 cells in a concentration-dependent manner. Chelation of intracellular calcium with BAPTA did not affect iron uptake, which indicates that the inhibitory effect of calcium is not exerted through intracellular calcium signaling. Kinetic studies performed, provided evidence that calcium acts as a reversible noncompetitive inhibitor of the iron transport activity of DMT1. Based on these experimental results, a mathematical model was developed that considers the dynamics of noncompetitive inhibition using a four-state mechanism to describe the inhibitory effect of calcium on the DMT1 iron transport process in intestinal cells. The model accurately predicts the calcein fluorescence quenching dynamics observed experimentally after an iron challenge. Therefore, the proposed model structure is capable of representing the inhibitory effect of extracellular calcium on DMT1-mediated iron entry into the cLIP of Caco-2 cells. Considering the range of calcium concentrations that can inhibit iron uptake, the possible inhibition of dietary calcium on intestinal iron uptake is discussed.


Assuntos
Proteínas de Transporte de Cátions , Ferro , Humanos , Ferro/metabolismo , Células CACO-2 , Cálcio , Cálcio da Dieta , Proteínas de Transporte de Cátions/metabolismo , Cinética , Absorção Intestinal , Modelos Teóricos
5.
J Invertebr Pathol ; 194: 107804, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35933037

RESUMO

Ascosphaera (Eurotiomycetes: Onygenales) is a diverse genus of fungi that is exclusively found in association with bee nests and comprises both saprophytic and entomopathogenic species. To date, most genomic analyses have been focused on the honeybee pathogen A. apis, and we lack a genomic understanding of how pathogenesis evolved more broadly in the genus. To address this gap we sequenced the genomes of the leaf-cutting bee pathogen A. aggregata as well as three commensal species: A. pollenicola, A. atra and A. acerosa. De novo annotation and comparison of the assembled genomes was carried out, including the previously published genome of A. apis. To identify candidate virulence genes in the pathogenic species, we performed secondary metabolite-oriented analyses and clustering of biosynthetic gene clusters (BGCs). Additionally, we captured single copy orthologs to infer their phylogeny and created codon-aware alignments to determine orthologs under selective pressure in our pathogenic species. Our results show several shared BGCs between A. apis, A. aggregata and A. pollenicola, with antifungal resistance related genes present in the bee pathogens and commensals. Genes involved in metabolism and protein processing exhibit signatures of enrichment and positive selection under a fitted branch-site model. Additional known virulence genes in A. pollenicola, A. acerosa and A. atra are identified, supporting previous hypotheses that these commensals may be opportunistic pathogens. Finally, we discuss the importance of such genes in other fungal pathogens, suggesting a common route to evolution of pathogenicity in Ascosphaera.


Assuntos
Ascomicetos , Onygenales , Animais , Antifúngicos , Ascomicetos/genética , Abelhas , Genômica , Onygenales/genética , Filogenia
6.
Aesthetic Plast Surg ; 46(1): 258-264, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34351508

RESUMO

Liposuction remains one of the most frequently performed cosmetic surgical procedures and its popularity is increasing every year. However, since its inception, justified concerns regarding patient safety have placed limits on the volume of fat that can be aspirated, influenced by hemodynamic fluctuations and blood loss during liposuction. Tranexamic acid (TXA) is an antifibrinolytic agent that competitively inhibits the conversion of plasminogen to plasmin, thus preventing the binding and degradation of fibrin. Despite the existence of evidence of the effectiveness of TXA in orthopedic and cardiac surgeries, there is little evidence of its use in liposuction. The objective of this study was to evaluate the efficacy and safety of tranexamic acid in the control of surgical bleeding in patients undergoing liposuction, through a prospective, open, randomized and controlled clinical trial. Two groups of 25 participants each were formed to whom the application of TXA in a tumescent solution prior to liposuction or liposuction with the traditional technique was randomly assigned. The results showed a decrease in blood loss reflected by the differences in the final hematocrit values, as well as decrease in the same per aspirated volume (p = 0.003). No adverse events were found related with the TXA application and no blood transfusions were required in this group, in contrast to the control group where the need for blood transfusion was present in 20% of the intervened participants. LEVEL OF EVIDENCE II: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.


Assuntos
Lipectomia , Ácido Tranexâmico , Perda Sanguínea Cirúrgica/prevenção & controle , Humanos , Lipectomia/métodos , Estudos Prospectivos , Ácido Tranexâmico/uso terapêutico , Resultado do Tratamento
7.
Gac Med Mex ; 157(1): 110-114, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34125812

RESUMO

Spontaneous pneumomediastinum is defined as the presence of free air within the mediastinum without an apparent cause such as chest trauma. It is a benign, self-limiting condition that is conservatively treated. Clinical diagnosis is based on two symptoms: chest pain and dyspnea; and on a particular sign: subcutaneous emphysema. It has been reported in patients with influenza A (H1N1) and severe acute respiratory syndrome; however, it has been rarely observed in COVID-19 patients. In this work, we describe six male patients with COVID-19, aged between 27 and 82 years, who presented with spontaneous pneumomediastinum and subcutaneous emphysema; both conditions were completely resorbed with conservative management.


El neumomediastino espontáneo es la presencia de aire libre en el mediastino sin el antecedente de alguna causa como trauma de tórax. Es una condición benigna autolimitada que se trata en forma conservadora. El diagnóstico clínico se basa en dos síntomas: dolor torácico y disnea; y en un signo en particular: enfisema subcutáneo. Ha sido reportado en pacientes con influenza A (H1N1) y síndrome respiratorio agudo grave; sin embargo, ha sido raramente observado en pacientes con COVID-19. En este trabajo describimos seis pacientes del sexo masculino con COVID-19, con edades entre 27 y 82 años, que presentaron neumomediastino espontáneo y enfisema subcutáneo; ambos se reabsorbieron totalmente con manejo conservador.


Assuntos
COVID-19/complicações , Enfisema Mediastínico/etiologia , Enfisema Subcutâneo/etiologia , Adulto , Idoso de 80 Anos ou mais , Humanos , Masculino , Pessoa de Meia-Idade
8.
Phytopathology ; 110(2): 393-405, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31532351

RESUMO

Wheat blast is a devastating disease caused by the Triticum pathotype of Magnaporthe oryzae. M. oryzae Triticum is capable of infecting leaves and spikes of wheat. Although symptoms of wheat spike blast (WSB) are quite distinct in the field, symptoms on leaves (WLB) are rarely reported because they are usually inconspicuos. Two field experiments were conducted in Bolivia to characterize the change in WLB and WSB intensity over time and determine whether multispectral imagery can be used to accurately assess WSB. Disease progress curves (DPCs) were plotted from WLB and WSB data, and regression models were fitted to describe the nature of WSB epidemics. WLB incidence and severity changed over time; however, the mean WLB severity was inconspicuous before wheat began spike emergence. Overall, both Gompertz and logistic models helped to describe WSB intensity DPCs fitting classic sigmoidal shape curves. Lin's concordance correlation coefficients were estimated to measure agreement between visual estimates and digital measurements of WSB intensity and to estimate accuracy and precision. Our findings suggest that the change of wheat blast intensity in a susceptible host population over time does not follow a pattern of a monocyclic epidemic. We have also demonstrated that WSB severity can be quantified using a digital approach based on nongreen pixels. Quantification was precise (0.96 < r> 0.83) and accurate (0.92 < ρ > 0.69) at moderately low to high visual WSB severity levels. Additional sensor-based methods must be explored to determine their potential for detection of WLB and WSB at earlier stages.


Assuntos
Magnaporthe , Modelos Estatísticos , Imagem Óptica , Triticum , Bolívia , Magnaporthe/fisiologia , Doenças das Plantas/microbiologia , Fatores de Tempo , Triticum/microbiologia
9.
Niger J Clin Pract ; 23(4): 515-522, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32246659

RESUMO

OBJECTIVE: This paper aims to provide a Spanish version of the nursing students'' perceptions of instructor caring with content validity and reliability. METHODS: A forward and backward translation procedure was conducted, and a panel of 15 experts assessed face validity. Content validity was established by calculating content validity indexes for each item and for the scale. The internal consistency was assessed in a sample of 120 students. RESULTS: Content validity indexes resulted in higher than 0.78 for all items except Does not reveal any of his or her personal sides and serves as a trusted resource for personal problem solving; content validity index for the scale was 0.9 and Cronbach α was 0.942. DISCUSSION: Results regarding reliability were similar to that of other studies in which the nursing students' perceptions of instructor caring has been used as a measuring tool. Item 12 deletion implies a considerable improvement in internal consistency. CONCLUSION: The Spanish nursing students' perceptions of instructor caring is a valid and reliable tool to be used in the Spanish context. Its use will enhance the understanding of clinical mentors' impact on nursing students.


Assuntos
Empatia , Mentores/psicologia , Estudantes de Enfermagem/psicologia , Traduções , Competência Cultural , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes
10.
Plant Dis ; 103(6): 1101-1111, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31012820

RESUMO

Brome mosaic virus (BMV) is generally thought to be of little economic importance to crops; consequently, there is little information about its impact on wheat production under field conditions. After repeated detection of BMV in Ohio wheat fields at incidences up to 25%, the virus was isolated, sequenced, characterized, and tested for its impact on soft red winter wheat (SRWW). The Ohio isolate of brome mosaic virus (BMV-OH) was found to be >99% identical to a BMV-Fescue isolate (accession no. DQ530423-25) and capable of systemically infecting multiple monocot and dicot species, including cowpea and soybean, in experimental inoculations. BMV-OH was used in field experiments during the 2016 and 2017 growing seasons to quantify its effect on SRWW grain yield and development when inoculated at Feekes 1, 5, 8, and 10 in two to four cultivars. Cultivar and timing of inoculation had statistically significant (P < 0.05) main and interaction effects on grain yield, wheat growth, and multiple components of yield. Compared with noninoculated controls, BMV-OH reduced grain yield by up to 61% when inoculated at Feekes 1 and by as much as 25, 36, and 31% for inoculations at Feekes 5, 8, and 10, respectively. The magnitude of the yield reduction varied among cultivars and was associated with reductions in grain size and weight or plant population. These findings suggest that BMV could impact wheat productivity in Ohio and will serve as the basis for more large-scale investigations of the effects of this virus in commercial fields.


Assuntos
Bromovirus , Triticum , Bromovirus/fisiologia , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/virologia , Ohio , Estações do Ano , Triticum/crescimento & desenvolvimento , Triticum/virologia
11.
Plant Dis ; 103(2): 223-237, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30484755

RESUMO

Integrated Fusarium head blight (FHB) management programs consisting of different combinations of cultivar resistance class and an application of the fungicide prothioconazole + tebuconazole at or after 50% early anthesis were evaluated for efficacy against FHB incidence (INC; percentage of diseased spikes), index (IND; percentage of diseased spikelets per spike), Fusarium damaged kernel (FDK), deoxynivalenol (DON) toxin contamination, grain yield, and test weight (TW) in inoculated field trials conducted in 11 U.S. states in 2014 and 2015. Mean log response ratios and corresponding percent control values for INC, IND, FDK, and DON, and mean differences in yield and TW relative to a nontreated, inoculated susceptible check (S_CK), were estimated through network meta-analyses as measures of efficacy. Results from the analyses were then used to estimate the economic benefit of each management program for a range of grain prices and fungicide applications costs. Management programs consisting of a moderately resistant (MR) cultivar treated with the fungicide were the most efficacious, reducing INC by 60 to 69%, IND by 71 to 76%, FDK by 66 to 72%, and DON by 60 to 64% relative to S_CK, compared with 56 to 62% for INC, 68 to 72% for IND, 66 to 68% for FDK, and 58 to 61% for DON for programs with a moderately susceptible (MS) cultivar. The least efficacious programs were those with a fungicide application to a susceptible (S) cultivar, with less than a 45% reduction of INC, IND, FDK, or DON. All programs were more efficacious under conditions favorable for FHB compared with less favorable conditions, with applications made at 50% early anthesis being of comparable efficacy to those made 2 to 7 days later. Programs with an MS cultivar resulted in the highest mean yield increases relative to S_CK (541 to 753 kg/ha), followed by programs with an S cultivar (386 to 498 kg/ha) and programs with an MR cultivar (250 to 337 kg/ha). Integrated management programs with an MS or MR cultivar treated with the fungicide at or after 50% early anthesis were the most likely to result in a 50 or 75% control of IND, FDK, or DON in a future trial. At a fixed fungicide application cost, these programs were $4 to $319/MT more economically beneficial than corresponding fungicide-only programs, depending on the cultivar and grain price. These findings demonstrate the benefits of combining genetic resistance with a prothioconazole + tebuconazole treatment to manage FHB, even if that treatment is applied a few days after 50% early anthesis.


Assuntos
Resistência à Doença , Fungicidas Industriais , Fusarium , Triticum , Resistência à Doença/genética , Fungicidas Industriais/farmacologia , Fusarium/efeitos dos fármacos , Fusarium/genética , Doenças das Plantas/microbiologia , Triazóis/farmacologia , Triticum/microbiologia
12.
Lung ; 196(4): 393-400, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29637273

RESUMO

INTRODUCTION: microRNAs (miRNAs) are small non-coding 1RNAs that post-transcriptionally regulate gene expression. Recent evidence shows that adenosine deaminases that act on RNA (ADAR) can edit miRNAs. miRNAs are involved in the development of different diseases, such as idiopathic pulmonary fibrosis (IPF). In IPF, about 40% of the miRNAs are differentially expressed with respect to controls. Among these miRNAs, miRNA-21 has been found over-expressed in IPF and its targets are anti-fibrosing molecules such as PELI1 and SPRY2. The objective of this study is to determine the role of ADAR1 and 2 on the expression of miRNA-21 in human lung fibroblasts trough quantification of gene expression, protein levels, and overexpression of ADAR1 and 2. METHODS: Six control and six fibrotic primary fibroblast cell cultures were used for RNA extraction, ADAR1, ADAR2, PELI1, SPRY2, miRNA-21, and pri-miRNA-21 expression was measured. Subsequently, two fibrotic fibroblast cultures were used for overexpression of ADAR1 and ADAR2, and they were stimulated with TGFß1. Real-time PCR and Western blot were performed. RESULTS: ADAR1 is significantly downregulated in IPF fibroblasts; the overexpression of ADAR1 and ADAR2 reestablishes the expression levels of miRNA-21, PELI1, and SPRY2 in fibroblasts of patients with IPF. CONCLUSION: These changes in the processing of miRNAs have great value in pathology diagnosis, including lung diseases, and play an important role in the understanding of molecular mechanisms involved in the development of different pathologies, as well as representing new therapeutic targets.


Assuntos
Adenosina Desaminase/metabolismo , Fibroblastos/enzimologia , Fibrose Pulmonar Idiopática/enzimologia , Pulmão/enzimologia , MicroRNAs/metabolismo , Proteínas de Ligação a RNA/metabolismo , Adenosina Desaminase/genética , Estudos de Casos e Controles , Células Cultivadas , Fibroblastos/efeitos dos fármacos , Fibroblastos/patologia , Regulação Enzimológica da Expressão Gênica , Humanos , Fibrose Pulmonar Idiopática/genética , Fibrose Pulmonar Idiopática/patologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Pulmão/efeitos dos fármacos , Pulmão/patologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , MicroRNAs/genética , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Cultura Primária de Células , Processamento Pós-Transcricional do RNA , Proteínas de Ligação a RNA/genética , Fator de Crescimento Transformador beta1/farmacologia , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo
13.
J Vet Med Educ ; 43(4): 420-426, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27404548

RESUMO

The objective of this study is to present a high-fidelity bench model of cryopreserved stomachs that can be used while learning surgical skills. Thirty stomachs were harvested from Wistar rats at the end of non-abdominal research studies. The stomachs were washed with cold saline solution and filled with hyaluronic acid solution. The organs were then placed into cryovials and cryopreserved at -30 °C for 60 days. The stomachs were thawed to room temperature on the day of the surgical skills practice and two full-thickness incisions were made. Reporting on their experiences, 22 participants (73.33%) felt that the cryopreserved stomach was identical to in vivo rat stomachs, 24 (80.00%) reported that the stomach was easy to handle, and 27 (90%) reported the tissue was non-friable. Moreover, 29 participants (96.6%) finished the suturing without tears and 100% recommended it as a biomaterial for surgical training. The cryopreserved stomach is a practical, reproducible, low-cost, and high-fidelity bench model that allows surgical fellows to learn how to handle a stomach and improve their surgical abilities before performing surgery on patients or laboratory animals.


Assuntos
Competência Clínica , Educação em Veterinária/métodos , Ratos/cirurgia , Estômago/cirurgia , Cirurgia Veterinária/educação , Animais , Criopreservação/veterinária , Modelos Animais , Ratos Wistar
14.
Am J Physiol Cell Physiol ; 309(8): C558-67, 2015 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-26289753

RESUMO

Recent evidence shows that iron induces the endocytosis of the iron transporter dimetal transporter 1 (DMT1) during intestinal absorption. We, and others, have proposed that iron-induced DMT1 internalization underlies the mucosal block phenomena, a regulatory response that downregulates intestinal iron uptake after a large oral dose of iron. In this work, we investigated the participation of reactive oxygen species (ROS) in the establishment of this response. By means of selective surface protein biotinylation of polarized Caco-2 cells, we determined the kinetics of DMT1 internalization from the apical membrane after an iron challenge. The initial decrease in DMT1 levels in the apical membrane induced by iron was followed at later times by increased levels of DMT1. Addition of Fe(2+), but not of Cd(2+), Zn(2+), Cu(2+), or Cu(1+), induced the production of intracellular ROS, as detected by 2',7'-dichlorofluorescein (DCF) fluorescence. Preincubation with the antioxidant N-acetyl-l-cysteine (NAC) resulted in increased DMT1 at the apical membrane before and after addition of iron. Similarly, preincubation with the hydroxyl radical scavenger dimethyl sulfoxide (DMSO) resulted in the enhanced presence of DMT1 at the apical membrane. The decrease of DMT1 levels at the apical membrane induced by iron was associated with decreased iron uptake rates. A kinetic mathematical model based on operational rate constants of DMT1 endocytosis and exocytosis is proposed. The model qualitatively captures the experimental observations and accurately describes the effect of iron, NAC, and DMSO on the apical distribution of DMT1. Taken together, our data suggest that iron uptake induces the production of ROS, which modify DMT1 endocytic cycling, thus changing the iron transport activity at the apical membrane.


Assuntos
Endocitose/fisiologia , Células Epiteliais/fisiologia , Mucosa Intestinal/citologia , Ferro/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição/metabolismo , Transporte Biológico , Células CACO-2 , Humanos , Mucosa Intestinal/metabolismo , Fatores de Transcrição/genética
15.
J Chem Inf Model ; 55(7): 1349-60, 2015 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-26091526

RESUMO

Two of the possible catalytic mechanisms for neurotransmitter oxidative deamination by monoamine oxidase B (MAO B), namely, polar nucleophilic and hydride transfer, were addressed in order to comprehend the nature of their rate-determining step. The Quantum Chemical Cluster Approach was used to obtain transition states of MAO B complexed with phenylethylamine (PEA), benzylamine (BA), and p-nitrobenzylamine (NBA). The choice of these amines relies on their importance to address MAO B catalytic mechanisms so as to help us to answer questions such as why BA is a better substrate than NBA or how para-substitution affects substrate's reactivity. Transition states were later validated by comparison with the experimental free energy barriers. From a theoretical point of view, and according to the our reported transition states, their calculated barriers and structural and orbital differences obtained by us among these compounds, we propose that good substrates such as BA and PEA might follow the hydride transfer pathway while poor substrates such as NBA prefer the polar nucleophilic mechanism, which might suggest that MAO B can act by both mechanisms. The low free energy barriers for BA and PEA reflect the preference that MAO B has for hydride transfer over the polar nucleophilic mechanism when catalyzing the oxidative deamination of neurotransmitters.


Assuntos
Biocatálise , Monoaminoxidase/metabolismo , Teoria Quântica , Motivos de Aminoácidos , Benzilaminas/metabolismo , Humanos , Cinética , Modelos Moleculares , Monoaminoxidase/química , Fenetilaminas/metabolismo , Termodinâmica , Água/química
16.
J Comput Aided Mol Des ; 29(1): 37-46, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25338130

RESUMO

A MD simulation protocol was developed to model halogen bonding in protein-ligand complexes by inclusion of a charged extra point to represent the anisotropic distribution of charge on the halogen atom. This protocol was then used to simulate the interactions of cathepsin L with a series of halogenated and non-halogenated inhibitors. Our results show that chloro, bromo and iodo derivatives have progressively narrower distributions of calculated geometries, which reflects the order of affinity I > Br > Cl, in agreement with the IC50 values. Graphs for the Cl, Br and I analogs show stable interactions between the halogen atom and the Gly61 carbonyl oxygen of the enzyme. The halogen-oxygen distance is close to or less than the sum of the van der Waals radii; the C-X···O angle is about 170°; and the X···O=C angle approaches 120°, as expected for halogen bond formation. In the case of the iodo-substituted analogs, these effects are enhanced by introduction of a fluorine atom on the inhibitors' halogen-bonding phenyl ring, indicating that the electron withdrawing group enlarges the σ-hole, resulting in improved halogen bonding properties.


Assuntos
Catepsina L/antagonistas & inibidores , Inibidores de Cisteína Proteinase/química , Halogênios/química , Simulação de Dinâmica Molecular , Catepsina L/química , Catepsina L/metabolismo , Cristalografia por Raios X , Inibidores de Cisteína Proteinase/metabolismo , Concentração Inibidora 50 , Ligantes , Modelos Moleculares , Oxigênio/química , Relação Estrutura-Atividade
17.
J Appl Microbiol ; 118(3): 592-8, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25487785

RESUMO

AIMS: The effects of irradiation (gamma-rays and electron-beams), up to 10 kGy, in the antimicrobial activity of mushroom species (Boletus edulis, Hydnum repandum, Macrolepiota procera and Russula delica) differently processed (fresh, dried, freeze) were evaluated. METHODS AND RESULTS: Clinical isolates with different resistance profiles from hospitalized patients in Local Health Unit of Mirandela, Northeast of Portugal, were used as target micro-organisms. The mushrooms antimicrobial activity did not suffer significant changes that might compromise applying irradiation as a possible mushroom conservation technology. CONCLUSIONS: Two kGy dose (independently of using gamma-rays or electron-beams) seemed to be the most suitable choice to irradiate mushrooms. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides important results in antimicrobial activity of extracts prepared from irradiated mushroom species.


Assuntos
Agaricales/efeitos da radiação , Antibacterianos/efeitos da radiação , Elétrons , Raios gama , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Extratos Celulares/farmacologia , Humanos
18.
Fish Shellfish Immunol ; 39(2): 450-7, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24929243

RESUMO

Lectins participate in the immune mechanisms of crustaceans. They have been considered as humoral receptors for pathogen-associated molecular patterns; however, some reports suggest that lectins could regulate crustacean cellular functions. In the present study, we purified and characterized a serum lectin (CqL) from the hemolymph of Cherax quadricarinatus by affinity chromatography and determined its participation in the regulation of hemocytes' oxidative burst. CqL is a 290-kDa lectin in native form, constituted by 108, 80, and 29-kDa subunits. It is mainly composed of glycine, alanine, and a minor proportion of methionine and histidine. It showed no carbohydrates in its structure. CqL is composed of several isoforms, as determined by 2D-electrophoresis, and shows no homology with any crustacean protein as determined by Lc/Ms mass spectrometry. CqL agglutinated mainly rat and rabbit erythrocytes and showed a broad specificity for monosaccharides such as galactose, glucose, and sialic acid, as well as for glycoproteins, such as porcine stomach and bovine submaxillary mucin and fetuin. It is a Mn(2+)-dependent lectin. CqL recognized 8% of crayfish granular hemocytes and increased 4.2-fold the production of hemocytes' superoxide anion in vitro assays when compared with non-treated hemocytes. This effect showed the same specificity for carbohydrates as hemagglutination; moreover, superoxide dismutase and diphenyleneiodonium chloride were effective inhibitors of CqL oxidative-activation. The CqL homoreceptor is a 120-kDa glycoprotein identified in the hemocytes lysate. Our results suggest that CqL participates actively in the regulation of the generation of superoxide anions in hemocytes using NADPH-dependent mechanisms.


Assuntos
Astacoidea/química , Astacoidea/imunologia , Hemócitos/imunologia , Lectinas/análise , Testes de Aglutinação , Aminoácidos/análise , Animais , Western Blotting , Cromatografia de Afinidade , Eletroforese em Gel Bidimensional , Hemócitos/metabolismo , Hemolinfa/metabolismo , Imuno-Histoquímica , Lectinas/sangue , Lectinas/imunologia , Espectrometria de Massas , Fagocitose/imunologia , Espécies Reativas de Oxigênio/metabolismo , Explosão Respiratória/imunologia , Estatísticas não Paramétricas
19.
Eur J Clin Microbiol Infect Dis ; 31(12): 3397-405, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23010902

RESUMO

The aim of the present study is to evaluate the usefulness of two biomarkers-procalcitonin (PCT) and C-reactive protein (CRP)-in addition to the CURB-65 score for assessing the site of care and the etiology of non-severe community-acquired pneumonia (CAP). We conducted a prospective observational study from April 1, 2006, to June 30, 2007, in a single teaching hospital in northern Spain among patients with non-severe CAP. In addition to collecting data needed to determine the CURB-65 score, microbial cultures were taken and levels of PCT and CRP were measured. We compared the prognostic accuracy of these biomarkers with the CURB-65 score to predict hospitalization and microbial etiology using receiver operating characteristic (ROC) curves. A total of 344 patients with non-severe CAP were enrolled; 73 were admitted to the hospital and 271 were treated on an outpatient basis. An etiologic diagnostic was made for 44 %, with atypical pathogens predominating. Levels of PCT and CRP increased with increasing CURB-65 scores. Patients admitted to the hospital had higher PCT and CRP levels than outpatients (p < 0.001). For predicting hospitalization, PCT had a better area under the ROC curve (AUC) (0.81) than the CURB-65 score alone (0.77). For PCT plus the CURB-65 score, the AUC increased significantly from 0.77 to 0.83. In patients with bacterial CAP, the biomarker levels were significantly higher than among patients with atypical or viral etiology (p < 0.001). PCT with a cut-off point of 0.15 ng/mL was the best predictor for bacterial etiology and for select patients eligible for outpatient care. In conclusion, levels of PCT and CRP positively correlate with increasing severity of CAP and may have a role in predicting both patients who can safely receive outpatient care and the microbial etiology in patients with low CURB-65 scores.


Assuntos
Biomarcadores/análise , Proteína C-Reativa/análise , Calcitonina/sangue , Infecções Comunitárias Adquiridas/diagnóstico , Infecções Comunitárias Adquiridas/terapia , Técnicas de Apoio para a Decisão , Pneumonia Bacteriana/diagnóstico , Pneumonia Bacteriana/terapia , Pneumonia Viral/diagnóstico , Pneumonia Viral/terapia , Precursores de Proteínas/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Assistência Ambulatorial , Peptídeo Relacionado com Gene de Calcitonina , Medicina Clínica/métodos , Feminino , Hospitalização , Hospitais de Ensino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Curva ROC , Espanha
20.
J Chem Inf Model ; 52(5): 1213-21, 2012 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-22540832

RESUMO

Although substrate conversion mediated by human monoaminooxidase (hMAO) has been associated with the deprotonated state of their amine moiety, data regarding the influence of protonation on substrate binding at the active site are scarce. Thus, in order to assess protonation influence, steered molecular dynamics (SMD) runs were carried out. These simulations revealed that the protonated form of the substrate serotonin (5-HT) exhibited stronger interactions at the protein surface compared to the neutral form. The latter displayed stronger interactions in the active site cavity. These observations support the possible role of the deprotonated form in substrate conversion. Multigrid docking studies carried out to rationalize the role of 5-HT protonation in other sites besides the active site indicated two energetically favored docking sites for the protonated form of 5-HT on the enzyme surface. These sites seem to be interconnected with the substrate/inhibitor cavity, as revealed by the tunnels observed by means of CAVER program. pK(a) calculations in the surface loci pointed to Glu³²7, Asp³²8, His488, and Asp¹³² as candidates for a possible in situ deprotonation step. Docking analysis of a group of inhibitors (structurally related to substrates) showed further interactions with the same two docking access sites. Interestingly, the protonated/deprotonated amine moiety of almost all compounds attained different docking poses in the active site, none of them oriented to the flavin moiety, thus producing a more variable and less productive orientations to act as substrates. Our results highlight the role of deprotonation in facilitating substrate conversion and also might reflect the necessity of inhibitor molecules to adopt specific orientations to achieve enzyme inhibition.


Assuntos
Simulação de Dinâmica Molecular , Inibidores da Monoaminoxidase/farmacologia , Monoaminoxidase/química , Prótons , Teoria Quântica , Sítios de Ligação , Domínio Catalítico , Humanos , Concentração Inibidora 50 , Modelos Moleculares , Monoaminoxidase/efeitos dos fármacos , Especificidade por Substrato
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