Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Spectrochim Acta A Mol Biomol Spectrosc ; 290: 122250, 2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-36566533

RESUMO

Fluorophores with optimized nonlinear optical properties have become prominent as contrast labels in laser scanning microscopy (LSM). The purpose of this work is to report on a novel benzothiadiazole derivative, namely 4,7-bis(5-((9,9-dioctyl-9H-fluoren-2-yl)ethynyl)thiophen-2-yl)benzo[c][1,2,5]thiadiazole (EFBT) and its optical performance when it is loaded into organic nanostructures intended as labels for LSM. Four different nanostructured labels were prepared: i) EFBT-loaded silica nanoparticles (SiNPs); ii) folate-bioconjugated SiNPs (SiNPs-FA); iii) EFBT-loaded PEGylated nanoparticles (NPs-PEG); and iv) EFBT-loaded folate-terminated PEGylated nanoparticles (NPs-PEG-FA). All these nanostructures are reported through a comparative study of their linear and nonlinear optical properties, including their performance as exogenous label agents in the cervical cancer cell line HeLa. This assessment of the performance of a specific fluorophore loaded into different nanostructured matrices (labels), and fairly compared under the same characterization conditions, including the LSM settings, is less common while previous reports had focused in comparing silica and PEGylated nanoparticles but loaded with different fluorophores. The results show that the internal molecular organization into each type of organic nanostructure impacted differently the properties of EFBT, where the silica matrix tend to preserve the optical performance of the fluorophore by preventing intermolecular interactions; in contrast, PEGylated nanoparticles favored molecular interactions and introduced non-radiative decay channels that degrades drastically the optical performance. Nevertheless, the use of functionalized ends entities produced a better cellular label uptake with PEGylated that with silica nanoparticles. In overall, the NPs-PEG-FA label produced the best HeLa imaging.


Assuntos
Nanopartículas , Tiadiazóis , Humanos , Células HeLa , Corantes Fluorescentes/química , Polietilenoglicóis/química , Ácido Fólico/química , Dióxido de Silício , Nanopartículas/química
3.
Int J Biol Macromol ; 142: 724-731, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31622723

RESUMO

Fluorescent carbon based-nanoparticles are one of the emerging nanomaterials. Their preparation is relatively simple, rapid and inexpensive, and they are less toxic compared with metal and semiconductor nanoparticles. Here, we report a simple and reliable method to prepare water-soluble fluorescent carbon nanoparticles (FC-NPs) from nanoparticles made from a protein, bovine serum albumin. The obtained mean size of our carbon nanoparticles is between 3.8 and 3.4 nm, and they exhibit its maximum fluorescence emission at 424 and 408 nm respectively (with a reasonable QY of 16.5%) due to the presence of functional groups (NH, NH2, COOH and OH) that contain O and N; the presence of these functional groups was confirmed by FTIR and XPS analysis. The photoluminescent decay lifetime was modeled by a two exponential fit which indicates a contribution from both core and surface states. Also, the preliminary results showed that FC-NPs had a good interaction with HeLa and normal oral epithelial cells; nanoparticles were permeable at the cell membrane and went to the cytosol, and even to the nucleus, in less than 30 min, the fluorescence images of our preliminary results did not show any apparent toxic damage in any of the cell lines.


Assuntos
Carbono/química , Corantes Fluorescentes/química , Nanopartículas/química , Soroalbumina Bovina/química , Aminas/química , Animais , Ácidos Carboxílicos/química , Bovinos , Permeabilidade da Membrana Celular , Células Epiteliais , Células HeLa , Humanos , Interações Hidrofóbicas e Hidrofílicas , Imagem Óptica , Espectrometria de Fluorescência , Propriedades de Superfície
4.
Toxicol In Vitro ; 42: 114-122, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28414162

RESUMO

In this work, gold nanospheres functionalized with low weight organic molecules (4-aminothiphenol and cysteamine) were synthesized in a one-step method for their in vitro cytotoxic evaluation on HeLa cells. To enhance the biocompatibility of the cysteamine-capped GNPs, BSA was used due to its broad PH stability and high binding affinity to gold nanoparticles. Besides, the widely reported silica coated gold nanorods were tested here to contrast their toxic response against our nanoparticles coated with organic molecules. Our results shown, the viability measured at 1.9×10-5M did not show significant differences against negative controls for all the samples; however, the metabolic activity of HeLa cells dropped when they were exposed to silica gold nanorods in the range of concentrations from 2.9×10-7M to 3.0×10-4M, while in the cases of gold nanospheres, we found that only at concentrations below 1.9×10-5M metabolic activity was normal. Our preliminary results did not indicate any perceivable harmful toxicity to cell membrane, cytoskeleton or nucleus due to our nanospheres at 1.9×10-5M. Additional test should be conducted in order to ensure a safe use of them for biological applications, and to determine the extent of possible damage.


Assuntos
Ouro/toxicidade , Nanopartículas Metálicas/toxicidade , Compostos de Anilina/química , Sobrevivência Celular/efeitos dos fármacos , Cisteamina/química , Citoesqueleto/efeitos dos fármacos , Ouro/química , Células HeLa , Humanos , Nanopartículas Metálicas/química , Nanotubos/química , Nanotubos/toxicidade , Soroalbumina Bovina/química , Dióxido de Silício/química , Compostos de Sulfidrila/química
5.
Int Angiol ; 34(2): 97-149, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24566499

RESUMO

Venous malformations (VMs) are the most common vascular developmental anomalies (birth defects) . These defects are caused by developmental arrest of the venous system during various stages of embryogenesis. VMs remain a difficult diagnostic and therapeutic challenge due to the wide range of clinical presentations, unpredictable clinical course, erratic response to the treatment with high recurrence/ persistence rates, high morbidity following non-specific conventional treatment, and confusing terminology. The Consensus Panel reviewed the recent scientific literature up to the year 2013 to update a previous IUP Consensus (2009) on the same subject. ISSVA Classification with special merits for the differentiation between the congenital vascular malformation (CVM) and vascular tumors was reinforced with an additional review on syndrome-based classification. A "modified" Hamburg classification was adopted to emphasize the importance of extratruncular vs. truncular sub-types of VMs. This incorporated the embryological ongm, morphological differences, unique characteristics, prognosis and recurrence rates of VMs based on this embryological classification. The definition and classification of VMs were strengthened with the addition of angiographic data that determines the hemodynamic characteristics, the anatomical pattern of draining veins and hence the risk of complication following sclerotherapy. The hemolymphatic malformations, a combined condition incorporating LMs and other CVMs, were illustrated as a separate topic to differentiate from isolated VMs and to rectify the existing confusion with name-based eponyms such as Klippei-Trenaunay syndrome. Contemporary concepts on VMs were updated with new data including genetic findings linked to the etiology of CVMs and chronic cerebrospinal venous insufficiency. Besides, newly established information on coagulopathy including the role of D-Dimer was thoroughly reviewed to provide guidelines on investigations and anticoagulation therapy in the management of VMs. Congenital vascular bone syndrome resulting in angio-osteo-hyper/hypotrophy and (lateral) marginal vein was separately reviewed. Background data on arterio-venous malformations was included to differentiate this anomaly from syndromebased VMs. For the treatment, a new section on laser therapy and also a practical guideline for follow up assessment were added to strengthen the management principle of the multidisciplinary approach. All other therapeutic modalities were thoroughly updated to accommodate a changing concept through the years.


Assuntos
Diagnóstico por Imagem/normas , Procedimentos Endovasculares/normas , Escleroterapia/normas , Malformações Vasculares/diagnóstico , Malformações Vasculares/terapia , Procedimentos Cirúrgicos Vasculares/normas , Biópsia , Terapia Combinada , Consenso , Diagnóstico por Imagem/métodos , Procedimentos Endovasculares/efeitos adversos , Humanos , Equipe de Assistência ao Paciente/normas , Seleção de Pacientes , Valor Preditivo dos Testes , Fatores de Risco , Escleroterapia/efeitos adversos , Terminologia como Assunto , Resultado do Tratamento , Malformações Vasculares/classificação , Procedimentos Cirúrgicos Vasculares/efeitos adversos , Veias/anormalidades
6.
Int Angiol ; 2014 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-24961611

RESUMO

Venous malformations (VMs) are the most common vascular developmental anomalies (birth defects). These defects are caused by developmental arrest of the venous system during various stages of embryogenesis. VMs remain a difficult diagnostic and therapeutic challenge due to the wide range of clinical presentations, unpredictable clinical course, erratic response to the treatment with high recurrence/persistence rates, high morbidity following nonspecific conventional treatment, and confusing terminology. The Consensus Panel reviewed the recent scientific literature up to the year 2013 to update a previous IUP Consensus (2009) on the same subject. ISSVA Classification with special merits for the differentiation between the congenital vascular malformation (CVM) and vascular tumors was reinforced with an additional review on syndrome-based classification. A "modified" Hamburg classification was adopted to emphasize the importance of extratruncular vs. truncular subtypes of VMs. This incorporated the embryological origin, morphological differences, unique characteristics, prognosis and recurrence rates of VMs based on this embryological classification. The definition and classification of VMs were strengthened with the addition of angiographic data that determines the hemodynamic characteristics, the anatomical pattern of draining veins and hence the risk of complication following sclerotherapy. The hemolymphatic malformations, a combined condition incorporating LMs and other CVMs, were illustratedas a separate topic to differentiate from isolated VMs and to rectify the existing confusion with namebased eponyms such as Klippel-Trenaunay syndrome. Contemporary concepts on VMs were updated with new data including genetic findings linked to the etiology of CVMs and chronic cerebrospinal venous insufficiency. Besides, newly established information on coagulopathy including the role of D-Dimer was thoroughly reviewed to provide guidelines on investigations and anticoagulation therapy in the management of VMs. Congenital vascular bone syndrome resulting in angio-osteo-hyper/hypotrophy and (lateral) marginal vein was separately reviewed. Background data on arterio-venous malformations was included to differentiate this anomaly from syndrome-based VMs. For the treatment, a new section on laser therapy and also a practical guideline for follow up assessment were added to strengthen the management principle of the multidisciplinary approach. All other therapeutic modalities were thoroughly updated to accommodate a changing concept through the years.

7.
Parasitology ; 141(4): 531-41, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24476561

RESUMO

Free-living amoebae belonging to the genus Acanthamoeba are the causative agents of infections such as amoebic keratitis (AK), granulomatous amoebic encephalitis (GAE) and cutaneous lesions. The mechanisms involved in the establishment of infection are unknown. However, it is accepted that the initial phase of pathogenesis involves adherence to the host tissue. In this work, we analysed surface molecules with an affinity for epithelial and neuronal cells from the trophozoites of Acanthamoeba castellanii. We also investigated the cellular mechanisms that govern the process of trophozoite adhesion to the host cells. We first used confocal and epifluorescence microscopy to examine the distribution of the A. castellanii actin cytoskeleton during interaction with the host cells. The use of drugs, as cytochalasin B (CB) and latrunculin B (LB), revealed the participation of cytoskeletal filaments in the adhesion process. In addition, to identify the proteins and glycoproteins on the surface of A. castellanii, the trophozoites were labelled with biotin and biotinylated lectins. The results revealed bands of surface proteins, some of which were glycoproteins with mannose and N-acetylglucosamine residues. Interaction assays of biotinylated amoebae proteins with epithelial and neuronal cells showed that some surface proteins had affinity for both cell types. The results of this study provide insight into the biochemical and cellular mechanisms of the Acanthamoeba infection process.


Assuntos
Acanthamoeba castellanii/fisiologia , Amebíase/parasitologia , Citoesqueleto/metabolismo , Interações Hospedeiro-Parasita , Acanthamoeba castellanii/efeitos dos fármacos , Acanthamoeba castellanii/patogenicidade , Acetilglucosamina/metabolismo , Citoesqueleto de Actina/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Adesão Celular , Linhagem Celular , Extensões da Superfície Celular/metabolismo , Citocalasina B/farmacologia , Células Epiteliais/parasitologia , Glicoproteínas/metabolismo , Humanos , Lectinas/metabolismo , Manose/metabolismo , Modelos Biológicos , Proteínas de Protozoários/metabolismo , Tiazolidinas/farmacologia , Trofozoítos
8.
J Econ Entomol ; 107(6): 2088-94, 2014 12.
Artigo em Inglês | MEDLINE | ID: mdl-26470073

RESUMO

The aloe mite, Aceria aloinis Keifer, causes physiological and morphological alterations in species of Aloe L. We conducted three trials to evaluate the potential of various miticides for curative and preventive control of damage caused by A. aloinis. In the first trial, the efficacy of nine miticides against aloe mite damage was assessed without the removal of infected tissue in Aloe reitziiae Reynolds. Although significant reductions in the number of mites and eggs were found due to the treatments, miticide application did not reduce the amount of plant area damaged or damage severity. Once the plants are infected, the irreversible damage by aloe mite progresses. The second trial analyzed the effects of seven miticides on aloe mite damage on Aloe 'Goliath' plants in which the damaged tissue was removed. Reduced damage severity and mite number was observed in all treated plants. To determine if aloe mite damage could be prevented, the effects of six miticides with and without surfactant were tested on uninfected plants of Aloe spinosissima A. Berger in a third trial. Except for chlorfenapyr and fenazaquin, all treatments reduced plant damaged area, damage severity, and the number of mites 60 wk following three miticide applications. The severity index in the second and third trials suggested that all treated plants would be marketable. Our study demonstrated that there were miticides that were effective by contact (carbaryl), translaminar (spiromesifen), and systemic (spirotetramat) action, which can be used to cure and to prevent aloe mite plant damage alone or in combination with cultural practices.


Assuntos
Acaricidas , Aloe , Ácaros , Controle de Pragas/métodos , Animais , California
9.
Int Angiol ; 32(1): 9-36, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23435389

RESUMO

Arterio-venous malformations (AVMs) are congenital vascular malformations (CVMs) that result from birth defects involving the vessels of both arterial and venous origins, resulting in direct communications between the different size vessels or a meshwork of primitive reticular networks of dysplastic minute vessels which have failed to mature to become 'capillary' vessels termed "nidus". These lesions are defined by shunting of high velocity, low resistance flow from the arterial vasculature into the venous system in a variety of fistulous conditions. A systematic classification system developed by various groups of experts (Hamburg classification, ISSVA classification, Schobinger classification, angiographic classification of AVMs,) has resulted in a better understanding of the biology and natural history of these lesions and improved management of CVMs and AVMs. The Hamburg classification, based on the embryological differentiation between extratruncular and truncular type of lesions, allows the determination of the potential of progression and recurrence of these lesions. The majority of all AVMs are extra-truncular lesions with persistent proliferative potential, whereas truncular AVM lesions are exceedingly rare. Regardless of the type, AV shunting may ultimately result in significant anatomical, pathophysiological and hemodynamic consequences. Therefore, despite their relative rarity (10-20% of all CVMs), AVMs remain the most challenging and potentially limb or life-threatening form of vascular anomalies. The initial diagnosis and assessment may be facilitated by non- to minimally invasive investigations such as duplex ultrasound, magnetic resonance imaging (MRI), MR angiography (MRA), computerized tomography (CT) and CT angiography (CTA). Arteriography remains the diagnostic gold standard, and is required for planning subsequent treatment. A multidisciplinary team approach should be utilized to integrate surgical and non-surgical interventions for optimum care. Currently available treatments are associated with significant risk of complications and morbidity. However, an early aggressive approach to elimiate the nidus (if present) may be undertaken if the benefits exceed the risks. Trans-arterial coil embolization or ligation of feeding arteries where the nidus is left intact, are incorrect approaches and may result in proliferation of the lesion. Furthermore, such procedures would prevent future endovascular access to the lesions via the arterial route. Surgically inaccessible, infiltrating, extra-truncular AVMs can be treated with endovascular therapy as an independent modality. Among various embolo-sclerotherapy agents, ethanol sclerotherapy produces the best long term outcomes with minimum recurrence. However, this procedure requires extensive training and sufficient experience to minimize complications and associated morbidity. For the surgically accessible lesions, surgical resection may be the treatment of choice with a chance of optimal control. Preoperative sclerotherapy or embolization may supplement the subsequent surgical excision by reducing the morbidity (e.g. operative bleeding) and defining the lesion borders. Such a combined approach may provide an excellent potential for a curative result. Conclusion. AVMs are high flow congenital vascular malformations that may occur in any part of the body. The clinical presentation depends on the extent and size of the lesion and can range from an asymptomatic birthmark to congestive heart failure. Detailed investigations including duplex ultrasound, MRI/MRA and CT/CTA are required to develop an appropriate treatment plan. Appropriate management is best achieved via a multi-disciplinary approach and interventions should be undertaken by appropriately trained physicians.


Assuntos
Malformações Arteriovenosas/diagnóstico , Malformações Arteriovenosas/terapia , Malformações Arteriovenosas/classificação , Malformações Arteriovenosas/etiologia , Malformações Arteriovenosas/fisiopatologia , Humanos , Terminologia como Assunto
10.
Dev Dyn ; 235(1): 191-202, 2006 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16252277

RESUMO

It is generally thought that the early pre-tubular chick heart is formed by fusion of the anterior or cephalic limits of the paired cardiogenic fields. However, this study shows that the heart fields initially fuse at their midpoint to form a transitory "butterfly"-shaped, cardiogenic structure. Fusion then progresses bi-directionally along the longitudinal axis in both cranial and caudal directions. Using in vivo labeling, we demonstrate that cells along the ventral fusion line are highly motile, crossing future primitive segments. We found that mesoderm cells migrated cephalically from the unfused tips of the anterior/cephalic wings into the head mesenchyme in the region that has been called the secondary heart field. Perturbing the anterior/cranial fusion results in formation of a bi-conal heart. A theoretical role of the ventral fusion line acting as a "heart organizer" and its role in cardia bifida is discussed.


Assuntos
Embrião de Galinha , Coração/embriologia , Animais , Imunofluorescência , Microscopia Confocal , Microscopia Eletrônica de Varredura , Coloração e Rotulagem
11.
Anat Rec ; 247(4): 512-20, 1997 04.
Artigo em Inglês | MEDLINE | ID: mdl-9096791

RESUMO

BACKGROUND: Because the studies on the embryological development of the primitive interventricular septum have been done with postmortem material, we do not know the site within the cardiac tube and the developmental stage at which the primordium appears and its anatomical manifestation in the mature heart. Consequently, we do not know its real contribution to the constitution of the definitive interventricular septum. METHODS: With this purpose, we selected an adequate biological model, the chick embryo heart and the in vivo labelling technique. We placed a label of gelatin India ink in the ventral fusion line of both cardiac primordia at the level of the interventricular grooves in the straight tube heart (stage 9+HH), and we traced the ink up to the mature heart (stage 36HH). We made histological sections of some hearts, of the zone where the label was found to investigate the first morphological manifestation of the primitive interventricular septum. We also made microdissections and scanning electron microscopic studies. RESULTS: The label placed at stage 9+HH in the ventral fusion line of both cardiac primordia, at the level of the interventricular grooves, was found at stage 14HH in the greater curvature of the looped heart, opposite the left interventricular groove. This label at stage 17HH was found in the apical trabecular region of the first cardiac septum (8-shaped septum) and in the mature heart (stage 36HH) in the definitive interventricular septum at the limit between the basal and the medial third of the definitive interventricular septum. CONCLUSIONS: Firstly, the primordium of the primitive interventricular septum appears at stage 9+HH, in the ventral fusion line of both cardiac primordia at the level of the interventricular grooves. Secondly, its first morphological manifestation takes place at stage 17HH, and it forms the apical trabeculated region of the first cardiac septum (8-shaped septum). Thirdly, the primitive interventricular septum gives origin to the middle and apical third of the definitive interventricular septum.


Assuntos
Septos Cardíacos/embriologia , Coração/embriologia , Animais , Embrião de Galinha , Microscopia Eletrônica de Varredura , Morfogênese
13.
Rev. chil. pediatr ; 53(4): 312-5, 1982.
Artigo em Espanhol | LILACS | ID: lil-7214

RESUMO

Se estudian 30 recien nacidos de madres con colestasia intrahepatica del embarazo y 30 controles. Ambos grupos tienen niveles comparables de bilirrubinemia en los primeros seis dias de vida. Se encontro un numero importante de muestras de leche materna y inhiben la conjugacion de bilirrubina in vitro, pero no hubo relacion con los niveles de bilirrubina serica de los recien nacidos. La capacidad inhibitoria de la leche materna es directamente proporcional al contenido total de acidos grasos libres de las muestras analizadas


Assuntos
Colestase Intra-Hepática , Icterícia Neonatal , Leite Humano , Complicações na Gravidez
14.
Surgery ; 85(1): 53-8, 1979 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-153004

RESUMO

Several methods of determining fibrinolytic activity were explored. The methods which gave the most satisfactory appraisal of the amount of fibrinolysin administered were as follows: euglobulin fraction on a prepared fibrin clot; euglobulin fraction method on benzoylarginine methyl ester; whole blood clot spontaneous lysis method. At present, the first of these three methods is the technique of choice. A preparation devised to observe the lysis of blood clots in vivo under the action of human fibrinolysin is described. In this preparation the successful lysis of fresh blood clots produced experimentally in segments of autogenous veins anastomosed to arteries was observed. The administration of plasmin by aerosol was followed by an increased lytic activity of the plasma of premature infants. Six patients in whom the clinical diagnosis of pulmonary hyaline membrane was made recovered completely after the treatment with human plasmin by aerosol. Forty-three percent of the children with the same diagnosis in whom plasmin was not used died (control subjects). Large doses of human fibrinolysin administered by the intravenous route prevented the formation of peritoneal adhesions in 100% of the animals treated. Adhesions developed in all of the dogs in which the intraperitoneal route was used. Fibrinolytic activity in the peripheral blood was increased considerably in all of the animals in which adhesions did not develop. No hemorrhagic phenomena other than slight oozing of the wounds were observed.


Assuntos
Fibrinolisina/uso terapêutico , Fibrinólise , Doença da Membrana Hialina/tratamento farmacológico , Doenças Peritoneais/tratamento farmacológico , Complicações Pós-Operatórias/tratamento farmacológico , Aerossóis , Animais , Cães , Avaliação de Medicamentos , Fibrinolisina/administração & dosagem , Fibrinólise/efeitos dos fármacos , Humanos , Recém-Nascido , Injeções Intraperitoneais , Injeções Intravenosas , Métodos , Aderências Teciduais/tratamento farmacológico
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...