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1.
Front Mol Neurosci ; 16: 1185796, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37324587

RESUMO

Introduction: CTCF-related disorder (CRD) is a neurodevelopmental disorder (NDD) caused by monoallelic pathogenic variants in CTCF. The first CTCF variants in CRD cases were documented in 2013. To date, 76 CTCF variants have been further described in the literature. In recent years, due to the increased application of next-generation sequencing (NGS), growing numbers of CTCF variants are being identified, and multiple genotype-phenotype databases cataloging such variants are emerging. Methods: In this study, we aimed to expand the genotypic spectrum of CRD, by cataloging NDD phenotypes associated with reported CTCF variants. Here, we systematically reviewed all known CTCF variants reported in case studies and large-scale exome sequencing cohorts. We also conducted a meta-analysis using public variant data from genotype-phenotype databases to identify additional CTCF variants, which we then curated and annotated. Results: From this combined approach, we report an additional 86 CTCF variants associated with NDD phenotypes that have not yet been described in the literature. Furthermore, we describe and explain inconsistencies in the quality of reported variants, which impairs the reuse of data for research of NDDs and other pathologies. Discussion: From this integrated analysis, we provide a comprehensive and annotated catalog of all currently known CTCF mutations associated with NDD phenotypes, to aid diagnostic applications, as well as translational and basic research.

2.
Toxicol In Vitro ; 78: 105258, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34653646

RESUMO

Air pollution has significant health effects worldwide, and airborne particles play a significant role in these effects. Ultrafine particles (UFPs) have an aerodynamic diameter of 0.1 µm or less, can penetrate deep into the respiratory tree, and are more toxic due to their large specific surface area, which should adsorb organic compounds. The aim of this study is to show the toxicological effects of UFPs with high organic content at low dose on BEAS-2B cells through at air-liquid interface (ALI) exposure using a Vitrocell® technology and a miniCAST (Combustion Aerosol Standard) generator. In conjunction with this approach, chemical analysis of particles and gas phase was performed to evaluate the presence of polycyclic aromatic hydrocarbons (PAHs). Chemical analyses confirmed the presence of PAHs in UFPs. With this experimental setup, exposure of the BEAS-2B cells induced neither cytotoxicity nor mitochondrial dysfunction. However, an increase of oxidative stress was observed, as assessed through Nrf2, NQO1, HO-1, CuZnSOD, MnSOD, and Catalase gene expression, together with significant induction of genes related to xenobiotic metabolism CYP1A1 and CYP1B1. Negative regulation of inflammatory genes expression (IL-6 and IL-8) was present three hours after the exposition to the UFPs. Taken together, this experimental approach, using repeatable conditions, should help to clarify the mechanisms by which organic UFPs induce toxicological effects.


Assuntos
Material Particulado/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/análise , Fuligem/toxicidade , Linhagem Celular , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Citocromo P-450 CYP1B1/genética , Citocromo P-450 CYP1B1/metabolismo , Humanos , Interleucinas/genética , Interleucinas/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Material Particulado/química , Fuligem/química
4.
J Colloid Interface Sci ; 575: 274-285, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32380319

RESUMO

During the agglomeration of nanoparticles and in particular, soot, a change in both the flow regime (from free molecular to near continuum) as well as the change of agglomeration regime (from ballistic to diffusive) is expected. However, these effects are rarely taken into account in numerical simulations of particle agglomeration and yet, they are suspected to have an important impact on the agglomeration kinetics, particle morphologies, and size distributions. This work intends to study these properties by using the Monte Carlo Aggregation Code (MCAC) presented in the preceding work (part 1), focusing on the physical impacts of varying the particle volume fraction and monomers size and polydispersity. The results show an important sensitivity of the kinetics of agglomeration, coagulation homogeneity, and agglomerate morphology to the size of monomers. First, for smaller monomer diameters, the agglomeration kinetic is enhanced and agglomerates are characterized by larger fractal dimensions. Second, for large monomer diameters, fractal dimensions down to 1.67 can be found being smaller than the classical 1.78 for Diffusion Limited Cluster Agglomeration (DLCA) mechanism. One important conclusion is that variation in time of both regimes has to be considered for a more accurate simulation of the agglomerate size distribution and morphology.

5.
J Colloid Interface Sci ; 569: 184-194, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32109672

RESUMO

The application of Monte Carlo methods to simulate the agglomeration of suspended nanoparticles is currently limited to specific agglomeration regimes with reduced accuracy in terms of the particle's physical residence time. The definition of specific particles persistent distance, its corresponding time step and subsequent probabilities for particle displacements may improve the accuracy of this method. To solve these issues, a new persistent distance and its corresponding time step based on Langevin dynamics simulations are introduced. Additionally, a probability of particle displacements, not restricted to a specific agglomeration regime, is introduced. All the modifications are validated by comparison with Langevin dynamics simulations. Finally, the above mentioned modifications considerably improve the accuracy of Monte Carlo methods to predict the dynamics and agglomeration of suspended nanoparticles.

6.
Andrologia ; 49(5)2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27401946

RESUMO

This study was performed to examine whether capsaicin, the main pungent ingredient of red peppers, exerts protective effects against testicular injuries induced by transient scrotal hyperthermia. Capsaicin (0.33 mg kg-1 ) was administered subcutaneously to mice one hour before heat stress (HS) in a 43°C water bath for 20 min. After 7 days, mice exposed to HS showed low testicular weight, severe vacuolisation of seminiferous tubules followed by loss of spermatogenic cells, and appearance of multinucleated giant cells and remarkable TUNEL-positive apoptotic cells, as well as weak immunoreactivity of phospholipid hydroperoxide glutathione peroxidase (PHGPx) in spermatogenic cells. Levels of lipid peroxidation and heat shock 70-kDa protein 1 (Hsp72) and BCL2-associated X protein (Bax) mRNA were greatly increased, but PHGPx, manganese superoxide dismutase (MnSOD), and B-cell lymphoma-extra large (Bcl-xL) mRNAs were significantly diminished in the testes by HS. However, capsaicin pre-treatment significantly suppressed the spermatogenic cell death, oxidative stress (levels of MDA, PHGPx immunoreactivity, and Hsp72, PHGPx, and MnSOD mRNA) and apoptosis (levels of TUNEL-positive cells, and Bcl-xL and Bax mRNA) in testes by HS. These suggest that capsaicin has a protective effect against spermatogenic cell death induced by scrotal hyperthermia through its antioxidative and anti-apoptotic activities.


Assuntos
Apoptose/efeitos dos fármacos , Capsaicina/administração & dosagem , Temperatura Alta , Escroto/fisiologia , Espermatogênese/fisiologia , Animais , Antioxidantes , Glutationa Peroxidase/análise , Glutationa Peroxidase/genética , Proteínas de Choque Térmico HSP72/genética , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Fosfolipídeo Hidroperóxido Glutationa Peroxidase , RNA Mensageiro/análise , Espermatogênese/efeitos dos fármacos , Espermatozoides/citologia , Espermatozoides/enzimologia , Espermatozoides/fisiologia , Superóxido Dismutase/genética , Testículo/química , Testículo/citologia , Testículo/fisiologia , Proteína X Associada a bcl-2/genética
7.
Sci Rep ; 6: 36495, 2016 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-27883014

RESUMO

Many studies have been conducted on the environmental impacts of combustion generated aerosols. Due to their complex composition and morphology, their chemical reactivity is not well understood and new developments of analysis methods are needed. We report the first demonstration of in-flight X-ray based characterizations of freshly emitted soot particles, which is of paramount importance for understanding the role of one of the main anthropogenic particulate contributors to global climate change. Soot particles, produced by a burner for several air-to-fuel ratios, were injected through an aerodynamic lens, focusing them to a region where they interacted with synchrotron radiation. X-ray photoelectron spectroscopy and carbon K-edge near-edge X-ray absorption spectroscopy were performed and compared to those obtained for supported samples. A good agreement is found between these samples, although slight oxidation is observed for supported samples. Our experiments demonstrate that NEXAFS characterization of supported samples provides relevant information on soot composition, with limited effects of contamination or ageing under ambient storage conditions. The highly surface sensitive XPS experiments of airborne soot indicate that the oxidation is different at the surface as compared to the bulk probed by NEXAFS. We also report changes in soot's work function obtained at different combustion conditions.

8.
Open Respir Med J ; 10: 36-45, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27499820

RESUMO

INTRODUCTION: Pranlukast is a leukotriene receptor antagonist (LTRA) that is used as an additional controller of mild to moderate asthma. This study compared the efficacy and side effects of two bioequivalent preparations of pranlukast: original pranlukast (Onon(®); Ono Pharmaceutical, Japan) and a modified formulation of pranlukast (Prakanon(®); Yuhan Co, Korea) in patients with mild to moderate asthma. METHODS: Of the 34 subjects screened, 30 patients who were using standard medication to control asthma and scored less than 20 points on the Asthma Control Test(™) (ACT) were assigned randomly to one of the two groups in a prospective, open label, crossover study: group 1 received Prakanon(®) (150 mg/day) and group 2 received Onon(®) (450 mg/day) for 8 weeks each; after a 1-week rest period, the groups were switched to the alternative medication for further 8 weeks and monitored for 2 more weeks without study medication. Evaluation parameters included the ACT, quality of life questionnaire adult Korean asthmatics (QLQAKA), pulmonary function tests, peripheral blood tests, vital signs, and adverse events. RESULTS: Thirty patients were enrolled and 21 completed the trial: 10 in group 1 and 11 in group 2. The baseline data of the two groups did not differ. No statistical significant differences were observed in efficacy and lung function at each time and in changes from baseline value between the two kinds of pranlukast. The final asthma control rate was 81% with Prakanon(®) and 76% with Onon(®). There were no differences in vital signs and laboratory data at each time and in changes from baseline value between the two drugs. There were no differences in adverse events between the two drugs. The most common side effect was abdominal pain. Drug compliance was high, without differences between the two drugs. CONCLUSION: These findings suggest that Prakanon(®) which is an improved formulation of pranlukast at a lower dose than the original formulation, Onon(®), has a similar efficacy and side effect profile in the control of persistent asthma.

10.
Sci Rep ; 5: 15696, 2015 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-26498694

RESUMO

The Laser-Induced Breakdown Detection technique (LIBD) was adapted to achieve fast in-situ characterization of nanoparticle beams focused under vacuum by an aerodynamic lens. The method employs a tightly focused, 21 µm, scanning laser microprobe which generates a local plasma induced by the laser interaction with a single particle. A counting mode optical detection allows the achievement of 2D mappings of the nanoparticle beams with a reduced analysis time thanks to the use of a high repetition rate infrared pulsed laser. As an example, the results obtained with Tryptophan nanoparticles are presented and the advantages of this method over existing ones are discussed.

11.
J Hazard Mater ; 283: 340-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25306534

RESUMO

For industrial concerns, and more especially for nuclear applications, the characterization of soot is essential for predicting the behaviour of containment barriers in fire conditions. This study deals with the characterization (emission factor, composition, size, morphology, microstructure) of particles produced during thermal degradation of materials found in nuclear facilities (electrical cables, polymers, oil and solvents). Small-scale experiments have been conducted for oxygen concentrations [O2] ranging from 15% to 21% in order to imitate the oxygen depletion encountered during a confined fire. Particles denote distinct shapes, from aggregates composed of monomers with diameters ranging from 31.2 nm to 52.8 nm, to compact nanoparticles with diameters ranging from 15 nm to 400 nm, and their composition strongly depends on fuel type. Despite the organic to total carbon ratio (OC/TC), their properties are poorly influenced by the decrease in [O2]. Finally, two empirical correlations are proposed for predicting the OC/TC ratio and the monomer diameter, respectively, as a function of the fuel's carbon to hydrogen ratio and the emission factor.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Incêndios , Centrais Nucleares , Material Particulado/análise
12.
Open Respir Med J ; 8: 48-54, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25614772

RESUMO

Angiosarcoma is a rare malignant tumor of soft tissue. Because angiosarcoma originates from endothelial cells, it can occur in any organ and shows aggressive clinical features. Most commonly, angiosarcoma initially presents as a cutaneous lesion. Lung metastasis from scalp angiosarcoma can develop pneumothorax. We report a case of multiorgan involvement of an angiosarcoma, including the scalp, initially presenting with hydropneumothorax. Immunohistochemistry analysis of the cells obtained from the study confirmed the pleural invasion of the angiosarcoma.

13.
J Hazard Mater ; 250-251: 298-307, 2013 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-23474404

RESUMO

Experimental results are reported on the resuspension of particles deposited on polymer samples representative of glove boxes used in the nuclear industry, under thermal degradation. A parametric study was carried out on the effects of heat flux, air flow rate, fuel type and particle size distribution. Small-scale experiments were conducted on 10 cm × 10 cm PolyMethyl MethAcrylate (PMMA) and PolyCarbonate (PC) samples covered with aluminium oxide particles with physical geometric diameters of 0.7 and 3.6 µm. It was observed for both polymer (fuel) samples that heat flux has no effect on the airborne release fraction (ARF), whereas particle size is a significant parameter. In the case of the PMMA sample, ARF values for 0.7 and 3.6 µm diameter particles range from 12.2% (± 6.2%) to 2.1% (± 0.6%), respectively, whereas the respective values for the PC sample range from 3.2% (± 0.8%) to 6.9% (± 3.9%). As the particle diameter increases, a significant decrease in particle release is observed for the PMMA sample, whereas an increase is observed for the PC sample. Furthermore, a peak airborne release rate is observed during the first instants of PMMA exposure to thermal stress. An empirical relationship has been proposed between the duration of this peak release and the external heat flux.


Assuntos
Polímeros/química , Aerossóis , Ar , Poluentes Atmosféricos , Poluição do Ar , Óxido de Alumínio/química , Monitoramento Ambiental/métodos , Desenho de Equipamento , Temperatura Alta , Cinética , Tamanho da Partícula , Cimento de Policarboxilato/química , Polimetil Metacrilato/química
14.
Orthod Craniofac Res ; 15(4): 245-54, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23020695

RESUMO

OBJECTIVES: To construct three-dimensional (3D) horizontal reference planes based on visual pathway and to determine their stability and reliability by analyzing the structural patterns of normal and dysmorphology for 3D craniofacial analysis. SETTING AND SAMPLE POPULATION: Thirty-six subjects with maxillofacial dysmorphology and malocclusion, and eight normal controls. MATERIALS AND METHODS POPULATION: On the 3D computed tomographic images of the subjects, the visual pathway-based planes, including the orbital axis plane (OAP), visual axis plane (VAP), and the optical axis plane (OpAP), were constructed and evaluated. RESULTS: The OAP, but not the VAP and OpAP, showed the ideal relationship between the midsagittal and posterior maxillary plane, and properly described the different patterns of maxillofacial dysmorphology with craniofacial plane 1 of Delaire's analysis and the occlusal plane. CONCLUSIONS: The proposed visual pathway-related horizontal reference planes, and in particular the OAP, seem to correctly express the visual axis and the position of the head in natural head position and can be used as a horizontal reference plane for the 3D analysis of craniofacial dysmorphology and anthropology.


Assuntos
Cefalometria/métodos , Anormalidades Craniofaciais/diagnóstico , Imageamento Tridimensional/métodos , Órbita/anatomia & histologia , Vias Visuais/anatomia & histologia , Vias Visuais/diagnóstico por imagem , Estudos de Casos e Controles , Cefalometria/normas , Face/anatomia & histologia , Cabeça , Humanos , Postura , Padrões de Referência , Reprodutibilidade dos Testes , Tomografia Computadorizada por Raios X
15.
Anat Histol Embryol ; 40(3): 210-8, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21323725

RESUMO

Gastrointestinal glutathione peroxidase (GI-GPx) is an antioxidant enzyme that has been known to be restricted to the gastrointestinal tract in rodents. In an effort to determine the expression pattern of GI-GPx mRNA during organogenesis, quantitative real-time PCR and in situ hybridization for GI-GPx mRNA were conducted in whole embryos or each developing organ of mice. GI-GPx mRNA was expressed more abundantly in the extraembryonic tissues, including placenta than in embryos on embryonic days (EDs) 7.5-18.5 (P < 0.05). When compared with the expression levels of cytosolic GPx (cGPx) mRNA, GI-GPx mRNA levels were low in the embryos, but relatively high in the extraembryonic tissues (P < 0.05). According to the results of whole mount in situ hybridizations, GI-GPx mRNA was principally expressed in the ectoplacental cone, neural tube and fold, and primitive heart at EDs 7.5-8.5. At EDs 9.5-12.5, GI-GPx mRNA was abundantly expressed in nervous tissues such as the telencephalon, mesencephalon and dorsal neural tube and was also detected in the forelimb and hindlimb at EDs 10.5-12.5. In the sectioned embryos after ED 13.5, GI-GPx mRNA levels were high in the cerebral cortex, metanephric corpuscle, pancreatic ducts, surface epithelia of the skin, inner ear, and nasal conchae, gastrointestinal tract, liver, urinary bladder, airway passages of lung, and whisker follicles. These findings indicate that GI-GPx is not only spatiotemporally expressed in a variety of embryonic organs during organogenesis but also may perform a mutual compensatory role with the cGPx in the protection of embryos and extraembryonic tissues against the reactive oxygen species generated in ontogenetic periods.


Assuntos
Embrião de Mamíferos/enzimologia , Trato Gastrointestinal/enzimologia , Regulação da Expressão Gênica no Desenvolvimento , Glutationa Peroxidase/genética , Organogênese , Animais , Membranas Extraembrionárias/enzimologia , Feminino , Trato Gastrointestinal/embriologia , Glutationa Peroxidase/biossíntese , Hibridização In Situ , Camundongos , Camundongos Endogâmicos ICR , Placenta/enzimologia , Reação em Cadeia da Polimerase , Gravidez , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio/metabolismo
16.
Rev Sci Instrum ; 80(10): 105105, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19895089

RESUMO

It is of practical importance to lead laboratory-scale experiments allowing a better understanding of the impact of commercial fuels composition on the formation of combustion residues such as soot particles. To this end, a hybrid burner has been designed recently to burn high-speed sprays of small liquid fuel droplets. It consists of a Holthuis (previously McKenna) burner originally equipped with a direct injection high efficiency nebulizer for the atomization of liquid hydrocarbons. A detailed description of this original setup is given in this paper. A priori estimations of atomization and evaporation times and length scales are then proposed and compared with experimental data. Droplet-size distribution measurements obtained in nonreacting conditions using a Malvern Spraytec particle sizer are presented and compared with values estimated by calculation. Cold sprays contours and liquid jet lengths in flames determined by Mie scattering at 532 and 1064 nm, respectively, are also presented. The results discussed in this work indicate that the hydrodynamic characteristics of the sprays generated with our system are relatively independent of the physical properties of fuels leading to comparable flames with identical liquid jet lengths, dimensions, and global structure. This feature facilitates an accurate comparison of flames burning various liquid hydrocarbons, which is of interest to emphasize differences in pollutants emissions and to highlight chemical effects for soot formation analysis.

17.
Ann N Y Acad Sci ; 1122: 69-82, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18077565

RESUMO

Frequent exposure of children to general anesthesia is common practice in modern medicine. Although previously unrecognized, recent in vitro and in vivo animal studies suggest that exposure to clinically relevant general anesthetics at the peak of brain development could be detrimental to immature mammalian neurons, as demonstrated by massive and widespread apoptotic neurodegeneration. The survival of the developing neurons presumably depends on proper and timely formation of synapses, for which synaptic proteins (e.g., synaptophysin, synaptobrevin, amphiphysin, synaptosomal-associated protein 25 [SNAP-25], and Ca(2+)/calmodulin-dependent protein kinase II [CaM kinase II]) are crucially important. Overinhibition of developing neurons impairs synaptic protein function and activity-induced synaptic plasticity, which could in turn result in permanent neuronal loss. To examine the effects of general anesthesia, the pharmacological agents known to cause extensive neuronal inhibition, on synaptic proteins, and neuronal survival at the peak of synaptogenesis, we exposed 7-day-old rat pups to general anesthesia (midazolam, 9 mg/kg of body weight, subcutaneously, followed by 6 h of nitrous oxide 75 vol% and isoflurane 0.75 vol%). We found that this general anesthesia causes permanent neuronal deletion in the most vulnerable brain regions-the cerebral cortex and the thalamus-while transiently modulating protein levels of synaptophysin, synaptobrevin, amphiphysin, SNAP-25, and CaM kinase II.


Assuntos
Anestésicos Inalatórios/efeitos adversos , Apoptose/efeitos dos fármacos , Encéfalo/citologia , Encéfalo/crescimento & desenvolvimento , Neurônios/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Proteínas do Tecido Nervoso/metabolismo , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
18.
Neuroscience ; 135(3): 815-27, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16154281

RESUMO

It was shown recently that exposure of the developing rat brain during the peak of synaptogenesis to commonly used general anesthetics can trigger widespread apoptotic neurodegeneration in many regions of the developing rat brain and persistent learning/memory deficits later on in life. To understand the mechanism by which general anesthetics induce apoptotic neuronal death we studied two common apoptotic pathways--the intrinsic and the extrinsic pathway--at different time points during synaptogenesis. We found that the intrinsic pathway is activated early on during anesthesia exposure (within two hours), as measured by the down-regulation of bcl-x(L), up-regulation of cytochrome c and the activation of caspase-9 in 7-day-old rats (the peak of synaptogenesis), but remains inactivated in 14-day-old rats (the end of synaptogenesis). The extrinsic pathway is activated later on (within six hours of anesthesia exposure), as measured by the up-regulation of Fas protein and the activation of caspase-8 in 7-day-old rats, but remains inactivated in 14-day-old rats. Anesthesia-induced apoptotic neurodegeneration is age dependent with vulnerability closely correlating with the timing of synaptogenesis, i.e. the developing brain is most sensitive at the peak of synaptogenesis (7 days old) and least sensitive at the end of synaptogenesis (14 days old).


Assuntos
Anestesia , Apoptose/fisiologia , Encéfalo/citologia , Encéfalo/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Transdução de Sinais/fisiologia , Anestésicos Inalatórios/farmacologia , Animais , Apoptose/efeitos dos fármacos , Gasometria , Western Blotting , Caspases/metabolismo , Morte Celular/efeitos dos fármacos , Circulação Cerebrovascular/efeitos dos fármacos , Citocromos c/fisiologia , Ativação Enzimática/efeitos dos fármacos , Fluxometria por Laser-Doppler , Óxido Nitroso/farmacologia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Proteína bcl-X/fisiologia , Receptor fas/biossíntese
19.
Braz J Med Biol Res ; 34(4): 419-35, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11285453

RESUMO

At the present time, protein folding is an extremely active field of research including aspects of biology, chemistry, biochemistry, computer science and physics. The fundamental principles have practical applications in the exploitation of the advances in genome research, in the understanding of different pathologies and in the design of novel proteins with special functions. Although the detailed mechanisms of folding are not completely known, significant advances have been made in the understanding of this complex process through both experimental and theoretical approaches. In this review, the evolution of concepts from Anfinsen's postulate to the "new view" emphasizing the concept of the energy landscape of folding is presented. The main rules of protein folding have been established from in vitro experiments. It has been long accepted that the in vitro refolding process is a good model for understanding the mechanisms by which a nascent polypeptide chain reaches its native conformation in the cellular environment. Indeed, many denatured proteins, even those whose disulfide bridges have been disrupted, are able to refold spontaneously. Although this assumption was challenged by the discovery of molecular chaperones, from the amount of both structural and functional information now available, it has been clearly established that the main rules of protein folding deduced from in vitro experiments are also valid in the cellular environment. This modern view of protein folding permits a better understanding of the aggregation processes that play a role in several pathologies, including those induced by prions and Alzheimer's disease. Drug design and de novo protein design with the aim of creating proteins with novel functions by application of protein folding rules are making significant progress and offer perspectives for practical applications in the development of pharmaceuticals and medical diagnostics.


Assuntos
Biotecnologia/tendências , Dobramento de Proteína , Animais , Biologia/tendências , Humanos , Medicina , Modelos Químicos , Fosfoglicerato Quinase/química , Príons/química , Conformação Proteica , Engenharia de Proteínas , Proteínas/química , Termodinâmica
20.
Braz. j. med. biol. res ; 34(4): 419-35, Apr. 2001. ilus, tab
Artigo em Inglês | LILACS | ID: lil-282607

RESUMO

At the present time, protein folding is an extremely active field of research including aspects of biology, chemistry, biochemistry, computer science and physics. The fundamental principles have practical applications in the exploitation of the advances in genome research, in the understanding of different pathologies and in the design of novel proteins with special functions. Although the detailed mechanisms of folding are not completely known, significant advances have been made in the understanding of this complex process through both experimental and theoretical approaches. In this review, the evolution of concepts from Anfinsen's postulate to the "new view" emphasizing the concept of the energy landscape of folding is presented. The main rules of protein folding have been established from in vitro experiments. It has been long accepted that the in vitro refolding process is a good model for understanding the mechanisms by which a nascent polypeptide chain reaches its native conformation in the cellular environment. Indeed, many denatured proteins, even those whose disulfide bridges have been disrupted, are able to refold spontaneously. Although this assumption was challenged by the discovery of molecular chaperones, from the amount of both structural and functional information now available, it has been clearly established that the main rules of protein folding deduced from in vitro experiments are also valid in the cellular environment. This modern view of protein folding permits a better understanding of the aggregation processes that play a role in several pathologies, including those induced by prions and Alzheimer's disease. Drug design and de novo protein design with the aim of creating proteins with novel functions by application of protein folding rules are making significant progress and offer perspectives for practical applications in the development of pharmaceuticals and medical diagnostics


Assuntos
Humanos , Animais , Biologia/tendências , Biotecnologia/tendências , Medicina , Dobramento de Proteína , Fosfoglicerato Quinase/química , Príons/química , Conformação Proteica , Engenharia de Proteínas , Proteínas/química , Termodinâmica
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