Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 43
Filtrar
1.
Sci Rep ; 12(1): 20131, 2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36418385

RESUMO

The control of the mechanism leading to the appearance of the ring-shaped stains from the dried liquid colloidal droplets has been the subject of intense studies over the last 25 years. This stems from the immense significance of this effect for technological applications. One of the key open topics in this field is the emergence of a regular multi-ring deposit from the dried droplet. Here, we show that magnetic nanoparticles in a drying magnetic liquid droplet can self-assemble into a multi-ring deposit structure, and even more importantly, a magnetic field can be turned on to control the underlying processes. The magnetic liquid is prepared as an aqueous suspension of Fe[Formula: see text]O[Formula: see text] magnetic nanoparticles stabilized with (3-Aminopropyl)triethoxysilane (APTES) and its droplets are placed on low-density polyethylene (LDPE) film. The results of this work are expected to be very promising in the case of multiple applications including ink-jet printing methods and 2D printed electronics.

2.
Rozhl Chir ; 101(6): 292-297, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35973826

RESUMO

INTRODUCTION: The publishing of our case report on an idiopathic compartment syndrome of both upper limbs after icing a contusion trauma was motivated by another article on the acute spontaneous compartment syndrome of upper limb published in Rozhledy v chirurgii 8/2021. CASE REPORT: We present the case of a 43-year-old man admitted in the evening for painful massive swelling of both upper extremities. The swelling developed immediately after icing his bruises suffered due to a probable fall on the previous day in a state of inebriety. Compartment syndrome of the left hand and right forearm was diagnosed; subsequently, adequate dermatofasciectomy resulted in normalization of the condition in both upper limbs. The patients condition was cured to a full extent without any disorders of perfusion, mobility or sensation in both upper extremities. CONCLUSION: Only few reports on the atraumatic compartment syndrome of upper extremity can be found in the literature and it is an acute condition encountered quite rarely at outpatient offices of surgery. Nevertheless, we need to be able to recognize this nosological unit and provide proper treatment in time, otherwise the patient may suffer serious permanent damage.


Assuntos
Síndromes Compartimentais , Doença Aguda , Adulto , Síndromes Compartimentais/diagnóstico , Síndromes Compartimentais/etiologia , Síndromes Compartimentais/cirurgia , Humanos , Masculino
3.
Phys Med Biol ; 66(15)2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34192680

RESUMO

A new radiochromic dosimeter was examined with Raman spectroscopy and an optical approach for assessment of 3D dose distribution integrity. The acronym of the dosimeter is Fricke-XO-Pluronic F-127, where XO denotes xylenol orange; Pluronic F-127 is a copolymer matrix of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide), and the dosimeter contains the components of a Fricke dosimetric solution. Two dosimeter samples in cuvettes were partially irradiated such that a radiation dose was absorbed at the bottom of the cuvettes. After irradiation, one sample was stored upside down such that the irradiated part was at the top and another one was stored with the irradiated part at the bottom. Two diffusion coefficients of ferric ion complexes with XO ([XO-Fe]+3) were calculated. They were compared with those for similar dosimeter, however with gelatine matrix instead of Pluronic F-127. The results obtained indicate an impact of the gravitational force on the diffusion of [XO-Fe]+3ions over time after irradiation and thus a possibility of severely undermining the integrity of a dose distribution in irradiated dosimeter. The conclusions drawn suggest the necessity of examination of different 3D Fricke dosimeter compositions for anisotropic diffusion of ferric ions.


Assuntos
Poloxâmero , Dosímetros de Radiação , Gelatina , Géis , Íons , Radiometria
4.
Osteoarthritis Cartilage ; 29(5): 739-749, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33610821

RESUMO

OBJECTIVE: Cartilage in joints such as the hip and knee experiences repeated phases of heavy loading and low load recovery during the 24-h day/night cycle. Our previous work has shown 24 h rhythmic changes in gene expression at transcript level between night and day in wild type mouse cartilage which is lost in a circadian clock knock-out mouse model. However, it remains unknown to what extent circadian rhythms also regulate protein level gene expression in this matrix rich tissue. METHODS: We investigated daily changes of protein abundance in mouse femoral head articular cartilage by performing a 48-h time-series LC-MS/MS analysis. RESULTS: Out of the 1,177 proteins we identified across all time points, 145 proteins showed rhythmic changes in their abundance within the femoral head cartilage. Among these were molecules that have been implicated in key cartilage functions, including CTGF, MATN1, PAI-1 and PLOD1 & 2. Pathway analysis revealed that protein synthesis, cytoskeleton and glucose metabolism exhibited time-of-day dependent functions. Analysis of published cartilage proteomics datasets revealed that a significant portion of rhythmic proteins were dysregulated in osteoarthritis and/or ageing. CONCLUSIONS: Our circadian proteomics study reveals that articular cartilage is a much more dynamic tissue than previously thought, with chondrocytes driving circadian rhythms not only in gene transcription but also in protein abundance. Our results clearly call for the consideration of circadian timing mechanisms not only in cartilage biology, but also in the pathogenesis, treatment strategies and biomarker detection in osteoarthritis.


Assuntos
Cartilagem Articular/metabolismo , Relógios Circadianos/fisiologia , Proteínas Circadianas Period/metabolismo , Proteômica , Animais , Condrócitos/metabolismo , Cromatografia Líquida , Relógios Circadianos/genética , Cabeça do Fêmur/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Knockout , Osteoartrite/genética , Osteoartrite/metabolismo , Proteínas Circadianas Period/genética , RNA Mensageiro/metabolismo , Espectrometria de Massas em Tandem
5.
Sci Rep ; 9(1): 17607, 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31772197

RESUMO

Through the use of the Monte Carlo simulations utilising the mean-field approach, we show that a dense assembly of separated ultra-small magnetic nanoparticles embedded into a non-magnetic deformable matrix can be characterized by a large isothermal magnetic entropy change even upon applying a weak magnetic field with values much smaller than one Tesla. We also show that such entropy change may be very significant in the vicinity of the room temperature which effect normally requires an application of a strong external magnetic field. The deformable matrix chosen in this work as a host for magnetic nanoparticles adopts a thin film form with a large surface area to volume ratio. This in turn in combination with a strong magneto-volume coupling exhibited by this material allows us to show its suitability to be used in the case of a variety of applications utilising local cooling/heating such as future magnetic refrigerants.

7.
Phys Chem Chem Phys ; 19(32): 21272-21275, 2017 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-28759068

RESUMO

Three novel tyrosine-conjugated azobenzene molecules were designed and their ability to target a natural chiral host matrix (human serum albumin, HSA) was investigated. We found that the interplay between the spatial configuration of the chiral substituents and the change in local symmetry resulting from the photoisomerization process strongly affects the optical activity of the bound photochromes. In particular, the different signal amplification obtained upon binding of the photoswitches to the biopolymer enables obtaining a chirooptical system tunable over a wide range of wavelengths.


Assuntos
Compostos Azo/metabolismo , Albumina Sérica Humana/metabolismo , Compostos Azo/química , Dicroísmo Circular , Humanos , Ligação Proteica , Albumina Sérica Humana/química , Espectrofotometria Ultravioleta , Estereoisomerismo , Tirosina/química
8.
J Biol Regul Homeost Agents ; 31(2): 365-369, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28685538

RESUMO

Since the successful collection of the first progenitor stem cells (SCs), there has been an increased interest in these cells as a model for undiscovered and unlimited potential of differentiation and development. Additionally, it was shown that SC populations display an ability to form pluripotent and/or totipotent cell populations. It was found that human ovarian granulosa cells (GCs) maintain a large capacity for differentiation into several other cell lineages, such as chondrogenic, osteogenic, neurogenic, and adipogenic, particularly during long-term, in vitro culture. In these cases, the specific media supplements that promote various pathways of differentiation, such as leukemia-inhibiting factor (LIF) and/or FSH, are well recognized. However, these are only some examples of the differentiation possibilities of human SCs in vitro and other pathways still require further investigation. Many SC populations, which are directed to differentiate into specific cell types, are also successfully used in several human disease therapies, e.g. leukemia. Moreover, SCs are used for tissue scaffold construction in patients with respiratory and cardiovascular diseases. In this review, the most recent knowledge about the in vitro growth and differentiation capacity of SCs is presented. Furthermore, we discuss the possible worldwide application of SCs in advanced cell and tissue bioengineering. In conclusion, it is suggested that, in the future, SCs will be a basic strategy in human therapy, and their use will open new gates in regenerative and reconstructive medicine in the 21st century.


Assuntos
Diferenciação Celular/fisiologia , Células-Tronco/citologia , Células-Tronco/fisiologia , Animais , Terapia Baseada em Transplante de Células e Tecidos/métodos , Terapia Baseada em Transplante de Células e Tecidos/tendências , Feminino , Células da Granulosa/citologia , Células da Granulosa/fisiologia , Humanos , Fator Inibidor de Leucemia/metabolismo , Masculino
9.
Fitoterapia ; 121: 194-205, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28728914

RESUMO

Thirteen new compounds including caffeoyl-glucaric and p-coumaroyl-altraric acid derivatives, one monoterpenoid glucoside, four secoiridoid glycosides, and three hydroxycinnamoyl phenylpropanoid glycosides esterified with an oleoside 11-methyl ester along with fifteen known compounds were isolated from flowers of Syringa vulgaris L. (Oleaceae). Their structures were elucidated by high-resolution spectroscopic methods. The tested compounds were able to decrease the production of reactive oxygen species. Moreover, oleoechinacoside (13), demethylhydroxyoleonuezhenide (14), demethyloleonuezhenide (15), syringaoleoacteoside (25) and oleoacteoside (26) at the concentration of 50µM, moderately suppressed the LPS-stimulated release of pro-inflammatory chemokine IL-8 and TNF-α from human neutrophils. Moreover, oleonuezhenide (12), oleoside 11-methyl ester (16) and oleoacteoside (26) at the concentration of 50µM were able to induce the surface expression of interleukin 10 receptor, which is suppressed by the incubation of monocyte/macrophage cells with LPS.


Assuntos
Anti-Inflamatórios/farmacologia , Flores/química , Glicosídeos Iridoides/farmacologia , Neutrófilos/efeitos dos fármacos , Syringa/química , Anti-Inflamatórios/isolamento & purificação , Células Cultivadas , Glucosídeos/isolamento & purificação , Glucosídeos/farmacologia , Glicosídeos , Humanos , Interleucina-8/metabolismo , Glicosídeos Iridoides/isolamento & purificação , Macrófagos/efeitos dos fármacos , Estrutura Molecular , Extratos Vegetais/química , Receptores de Interleucina-10/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
10.
J Neuroendocrinol ; 29(2)2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-28009489

RESUMO

Neurones expressing kisspeptin, neurokinin B and dynorphin A, located in the arcuate nucleus of the hypothalamus (ARC), are important regulators of reproduction. Their functions depend on metabolic and hormonal status. We hypothesised that male rats with high-fat diet-induced obesity (DIO) and/or streptozotocin-induced diabetes mellitus type 1 (DM1) and type 2 (DM2) will have alterations in numbers of immunoreactive (-IR) cells: kisspeptin-IR and/or neurokinin B-IR and dynorphin A-IR neurones in the ARC in the sham condition. In addition, orchidectomy alone (ORX) and with testosterone treatment (ORX+T) will unmask possible deficits in the response of these neurones in DIO, and/or DM1 and DM2 rats. Rats were assigned to four groups: a control (C) and one diabetic group (DM1) were fed a regular chow diet, whereas the obese group (DIO) and the other diabetic group (DM2) were fed a high-fat diet. To induce diabetes, streptozotocin was injected. After 6 weeks, each group was divided into three subgroups: ORX, ORX+T and sham. After another 2 weeks, metabolic and hormonal profiles were assessed and immunocytochemistry was performed. We found that: (1) under sham conditions: (i) DM1 and DM2 animals had higher numbers of kisspeptin-IR cells than controls and (ii) DM2 rats had increased numbers of neurokinin B-IR and dynorphin A-IR cells compared to C animals; (2) ORX and ORX+T treatments unmasked deficits of the studied neurones in DM1 and DM2 but not in DIO animals; and (3) DIO, DM1 and DM2 rats had altered metabolic and hormonal profiles, in particular decreased levels of testosterone. We concluded that alterations in numbers of kisspeptin-IR and neurokinin B-IR neurones in the ARC and their response to ORX and ORX+T may account for disruptions of metabolic and reproductive functions in diabetic but not in obese rats.


Assuntos
Núcleo Arqueado do Hipotálamo/metabolismo , Diabetes Mellitus Experimental/metabolismo , Dinorfinas/metabolismo , Kisspeptinas/metabolismo , Neurocinina B/metabolismo , Obesidade/metabolismo , Testosterona/farmacologia , Animais , Núcleo Arqueado do Hipotálamo/efeitos dos fármacos , Dieta Hiperlipídica/efeitos adversos , Masculino , Neurônios/metabolismo , Orquiectomia , Ratos , Testosterona/sangue
11.
Spectrochim Acta A Mol Biomol Spectrosc ; 173: 356-360, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-27685004

RESUMO

Recently reported new phenomenon of Aggregation-Induced Raman Optical Activity is demonstrated here for the first time in the pre-resonance conditions for lutein diacetate and 3'-epi-lutein supramolecular self-assembles. We demonstrate that minor alterations in the lutein structure (e.g. acetylation of hydroxyl groups or different configuration at one of the chiral center) can lead to definitely different spectral profiles and optical properties due to formation of aggregates of different structure and type. Lutein forms only H-aggregates, lutein diacetate only J-aggregates, while 3'-epi-lutein can occur in both forms simultaneously. Variety of aggregates' structures is so large that not only the type of aggregation is different, but also their chirality. It is remarkable that even in the pre-resonance conditions, aggregation of lutein derivatives can lead to the intense ROA signal, and moreover, 3'-epi-lutein demonstrated the highest resonance ROA CID ratio that has ever been reported.

12.
Neuropeptides ; 56: 41-9, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26853724

RESUMO

Recent data indicates that kisspeptin, encoded by the KISS1 gene, could play a role in transducing metabolic information into the hypothalamic-pituitary-gonadal (HPG) axis, the mechanism that controls reproductive functions. Numerous studies have shown that in a state of negative energy balance, the hypothalamic kisspeptin system is impaired. However, data concerning positive energy balance (e.g. diabetes and obesity) and the role of kisspeptin in the peripheral tissues is scant. We hypothesized that: 1) in diet-induced obese (DIO) male rats and/or rats with diabetes type 1 (DM1) and type 2 (DM2), altered reproductive functions are related to an imbalance in Kiss1 and GPR54 mRNA in the HPG axis; and 2) in DIO and/or DM1 and/or DM2 rats, Kiss1 and GPR 54 expression are altered in the peripheral tissues involved in metabolic functions (fat, pancreas and liver). Animals were fed a high-fat or control diets and STZ (streptozotocin - toxin, which destroys the pancreas) was injected in high or low doses to induce diabetes type 1 (DM1) or diabetes type 2 (DM2), respectively. RT-PCR and Western blot techniques were used to assess the expression of Kiss1 and GRP54 in tissues. At the level of mRNA, we found that diabetic but not obese rats have alterations in Kiss1 and/or GPR54 mRNA levels in the HPG axis as well as in peripheral tissues involved in metabolic functions (fat, pancreas and liver). The most severe changes were seen in DM1 rats. However, in the case of protein levels in the peripheral tissues (fat, pancreas and liver), changes in Kiss1/GPR54 expression were noticed in DIO, DM1 and DM2 animals and were tissue-specific. Our data support the hypothesis that alterations in Kiss1/GPR54 balance may account for both reproductive and metabolic abnormalities reported in obese and diabetic rats.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Gônadas/metabolismo , Hipotálamo/metabolismo , Kisspeptinas/metabolismo , Obesidade/metabolismo , Hipófise/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Dieta Hiperlipídica , Masculino , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Receptores de Kisspeptina-1
13.
J Biochem ; 159(4): 421-7, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26634446

RESUMO

Distribution of the isoelectric point (pI) was calculated for the hypervariable regions of Fab fragments of the antibody molecules, which structure is annotated in the structural antibody database SabDab. The distribution is consistent with the universal for all organisms dividing the proteome into two sets of acidic and basic proteins. It shows the additional fine structure in a form of the narrow-sized peaks of pI values. This is an explanation why a small change of the environmental pH can have a strong effect on the antibody-antigen affinity. To show this, a typical enzyme-linked immunospecific assay experiment for testing the reaction of goat anti-human IgA antibodies with human IgA immunoglobulins of saliva as antigens was modified in such a way that Fe3O4magnetic nanoparticles were added to PBS buffer. The magnetic nanoparticles were remotely heated by the radio frequency magnetic field providing the local change of temperature and pH. It was observed that short times of the heating were significantly increasing the antibody-antigen binding strength while it was not the case for a longer time. The finding discussed in the study can be useful for biopharmaceuticals using antibodies, the immunoassay techniques as well as for control over the use of hyperthermia.


Assuntos
Anticorpos/química , Reações Antígeno-Anticorpo , Antígenos/química , Temperatura Alta , Fragmentos Fab das Imunoglobulinas/química , Afinidade de Anticorpos , Ensaio de Imunoadsorção Enzimática/métodos , Humanos , Concentração de Íons de Hidrogênio , Imunoglobulina A/imunologia , Ponto Isoelétrico , Nanopartículas de Magnetita , Saliva/imunologia
14.
Mucosal Immunol ; 9(5): 1288-302, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-26627460

RESUMO

The Gram-positive bacterium Streptococcus pneumoniae causes life-threatening infections, especially among immunocompromised patients. The host's immune system senses S. pneumoniae via different families of pattern recognition receptors, in particular the Toll-like receptor (TLR) family that promotes immune cell activation. Yet, while single TLRs are dispensable for initiating inflammatory responses against S. pneumoniae, the central TLR adapter protein myeloid differentiation factor 88 (MyD88) is of vital importance, as MyD88-deficient mice succumb rapidly to infection. Since MyD88 is ubiquitously expressed in hematopoietic and non-hematopoietic cells, the extent to which MyD88 signaling is required in different cell types to control S. pneumoniae is unknown. Therefore, we used novel conditional knockin mice to investigate the necessity of MyD88 signaling in distinct lung-resident myeloid and epithelial cells for the initiation of a protective immune response against S. pneumoniae. Here, we show that MyD88 signaling in lysozyme M (LysM)- and CD11c-expressing myeloid cells, as well as in pulmonary epithelial cells, is critical to restore inflammatory cytokine and antimicrobial peptide production, leading to efficient neutrophil recruitment and enhanced bacterial clearance. Overall, we show a novel synergistic requirement of compartment-specific MyD88 signaling in S. pneumoniae immunity.


Assuntos
Células Epiteliais/imunologia , Pulmão/imunologia , Fator 88 de Diferenciação Mieloide/imunologia , Neutrófilos/imunologia , Pneumonia Pneumocócica/imunologia , Animais , Antígeno CD11c/genética , Antígeno CD11c/imunologia , Comunicação Celular/imunologia , Células Epiteliais/microbiologia , Regulação da Expressão Gênica , Técnicas de Introdução de Genes , Pulmão/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Muramidase/genética , Muramidase/imunologia , Fator 88 de Diferenciação Mieloide/genética , Infiltração de Neutrófilos , Neutrófilos/microbiologia , Pneumonia Pneumocócica/genética , Pneumonia Pneumocócica/microbiologia , Transdução de Sinais , Streptococcus pneumoniae/crescimento & desenvolvimento , Streptococcus pneumoniae/imunologia , Streptococcus pneumoniae/patogenicidade
15.
Osteoarthritis Cartilage ; 23(11): 1981-8, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26521744

RESUMO

OBJECTIVE: To define how the catabolic cytokines (Interleukin 1 (IL-1) and tumor necrosis factor alpha (TNFα)) affect the circadian clock mechanism and the expression of clock-controlled catabolic genes within cartilage, and to identify the downstream pathways linking the cytokines to the molecular clock within chondrocytes. METHODS: Ex vivo cartilage explants were isolated from the Cry1-luc or PER2::LUC clock reporter mice. Clock gene dynamics were monitored in real-time by bioluminescence photon counting. Gene expression changes were studied by qRT-PCR. Functional luc assays were used to study the function of the core Clock/BMAL1 complex in SW-1353 cells. NFкB pathway inhibitor and fluorescence live-imaging of cartilage were performed to study the underlying mechanisms. RESULTS: Exposure to IL-1ß severely disrupted circadian gene expression rhythms in cartilage. This effect was reversed by an anti-inflammatory drug dexamethasone, but not by other clock synchronizing agents. Circadian disruption mediated by IL-1ß was accompanied by disregulated expression of endogenous clock genes and clock-controlled catabolic pathways. Mechanistically, NFкB signalling was involved in the effect of IL-1ß on the cartilage clock in part through functional interference with the core Clock/BMAL1 complex. In contrast, TNFα had little impact on the circadian rhythm and clock gene expression in cartilage. CONCLUSION: In our experimental system (young healthy mouse cartilage), we demonstrate that IL-1ß (but not TNFα) abolishes circadian rhythms in Cry1-luc and PER2::LUC gene expression. These data implicate disruption of the chondrocyte clock as a novel aspect of the catabolic responses of cartilage to pro-inflammatory cytokines, and provide an additional mechanism for how chronic joint inflammation may contribute to osteoarthritis (OA).


Assuntos
Condrócitos/metabolismo , Relógios Circadianos/genética , Citocinas/genética , DNA/genética , Regulação da Expressão Gênica , NF-kappa B/genética , Osteoartrite/genética , Animais , Cartilagem Articular/metabolismo , Cartilagem Articular/patologia , Células Cultivadas , Citocinas/biossíntese , Modelos Animais de Doenças , Camundongos , Camundongos Transgênicos , NF-kappa B/biossíntese , Osteoartrite/metabolismo , Osteoartrite/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa
16.
Environ Technol ; 34(9-12): 1439-46, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24191477

RESUMO

The objective of the present study was to determine the effectiveness of biogas production during methane fermentation of wastewaters originating from the dairy, tanning and sugar industries, by means ofrespirometric measurements conducted at a temperature of 35 degrees C. Experiments were carried out with the use of model tanks of volume 0.5 dm3. A high production yield of biogas, with methane content exceeding 60%, was achieved in the case of the anaerobic treatment of wastewaters from the dairy and sugar industries. A significantly lower effect was observed in the case of tanning wastewaters. The effectiveness of the fermentation process decreased with increasing loading of the tanks with a feedstock of organic compounds. By loading a model tank with this feedstock, the effectiveness of treatment ranged from 62.8% to 71.4% residual chemical oxygen demand for dairy wastewaters and from 57.9% to 64.1% for sugar industry wastewaters. The efficiency of organic compound removal from tanning wastewaters was below 50%, regardless of the method applied.


Assuntos
Biocombustíveis/análise , Resíduos Industriais , Metano/análise , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Agricultura , Reatores Biológicos , Carboidratos , Indústria de Laticínios , Fermentação , Indústria Alimentícia , Metano/química , Metano/metabolismo , Curtume
17.
Oper Dent ; 38(6): 644-54, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23570299

RESUMO

The aim of this study was to determine the effect of peroxide bleaching on the marginal seal of composite restorations bonded with several adhesive systems. Combined cylindrical Class V cavities located half in enamel and half in dentin were prepared on the buccal and lingual surfaces of human molars. The cavities were bonded with the self-etch adhesives Clearfil SE-Bond (CLF), Adper Prompt (ADP), and iBond (IBO) and an etch-and-rinse adhesive Gluma Comfort Bond (GLU) and restored with a microhybrid composite Charisma. Experimental groups were treated 25 times for eight hours per day with a peroxide bleaching gel Opalescence PF 20, while the control groups were stored in distilled water for two months and then subjected to a microleakage test using a dye penetration method. Scanning electron microscopy was used to investigate the etching and penetration abilities of the adhesives and morphology of debonded restoration-enamel interfaces after the microleakage tests. Statistical analyses were performed using nonparametric Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests at p=0.05. The microleakage of all GLU groups was low and not significantly affected by peroxide bleaching. Low microleakage was recorded for CLF control groups, but after bleaching, a small but significant increase in microleakage at the enamel margin indicated its sensitivity to peroxide bleaching. For ADP and IBO control groups, the microleakage at the enamel margins was significantly higher than for GLU and CLF and exceeded that at the dentin margins. Bleaching did not induce any significant changes in the microleakage. Electron microscopy analysis indicated that in our experimental setup, decreased adhesion and mechanical resistance of the ADP- and IBO-enamel interfaces could be more important than the chemical degradation effects induced by the peroxide bleaching gel.


Assuntos
Resinas Compostas/uso terapêutico , Cimentos Dentários/uso terapêutico , Corrosão Dentária/métodos , Restauração Dentária Permanente/métodos , Clareamento Dental/métodos , Bis-Fenol A-Glicidil Metacrilato/uso terapêutico , Infiltração Dentária/etiologia , Infiltração Dentária/prevenção & controle , Adesivos Dentinários/uso terapêutico , Combinação de Medicamentos , Humanos , Dente Serotino , Organofosfatos/uso terapêutico , Peróxidos/farmacologia , Peróxidos/uso terapêutico , Polivinil/farmacologia , Polivinil/uso terapêutico , Cimentos de Resina/uso terapêutico , Clareadores Dentários/farmacologia , Ureia/análogos & derivados , Ureia/farmacologia , Ureia/uso terapêutico
18.
Oper Dent ; 38(4): 394-407, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23092146

RESUMO

This study investigated the effect of peroxide bleaching gel on the durability of the adhesive bond between composite material, enamel, and dentin created with the etch-and-rinse adhesive Gluma Comfort Bond (GLU) and with the self-etch adhesives Clearfil SE Bond (CLE), Adper Prompt (ADP), and iBond (IBO). The adhesives were applied to flattened enamel and dentin of extracted human molars and built up with a microhybrid composite (Charisma). After 25 eight-hour cycles of bleaching with a 20% carbamide peroxide bleaching gel (Opalescence PF 20), the shear bond strength was measured and compared with one-day and two-month control specimens stored in water. The data were analyzed using nonparametric Mann-Whitney and Kruskal-Wallis statistics (p<0.05). Detailed fractographic analysis was performed using scanning electron microscopy. The bleaching gel significantly decreased the bond strength on both enamel and dentin for the simplified single-step self-etch adhesives ADP and IBO and markedly affected a fracture pattern of ADP specimens at the periphery of their bonded area. The results of our study indicate that the durability of adhesive restorations can be detrimentally influenced by carbamide peroxide bleaching and that different adhesives show varying sensitivity levels to the bleaching gel.


Assuntos
Resinas Compostas/química , Colagem Dentária , Esmalte Dentário/ultraestrutura , Materiais Dentários/química , Dentina/ultraestrutura , Peróxidos/química , Clareadores Dentários/química , Ureia/análogos & derivados , Condicionamento Ácido do Dente/métodos , Bis-Fenol A-Glicidil Metacrilato/química , Peróxido de Carbamida , Adesivos Dentinários/química , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Organofosfatos/química , Cimentos de Resina/química , Resistência ao Cisalhamento , Estresse Mecânico , Propriedades de Superfície , Fatores de Tempo , Clareamento Dental/métodos , Ureia/química , Água/química
19.
Int J Lab Hematol ; 33(3): 272-80, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21118388

RESUMO

INTRODUCTION: The most commonly used test for monitoring heparin therapy is the activated partial thromboplastin time (aPTT). The response of available aPTT reagents to heparin varies significantly. The aim of this study was to highlight the differences between aPTT reagents stored in a dried format to select the most suitable formulations to be used for the development of point-of-care diagnostic devices used for monitoring of unfractionated heparin dose response. METHODS: Ten reagents were analysed in terms of their performance in liquid and in dried form after storage for 24 h and 14 days. Performance was assessed by measurement of the clotting time (CT) as evidenced by the onset of thrombin formation using a chromogenic thrombin substrate in plasma samples activated with these formulations. RESULTS: Reagents in all of the three forms tested (liquid, 24 h and 14 days) resulted in significant shortening of CTs in comparison with the nonactivated plasma CT. Liquids returned more rapid CTs in comparison with dried reagents. Most of the reagents were more sensitive to heparin in dried, rather than in liquid form. Dried reagents based on kaolin as a surface activator were notably more effective in achieving short CT than others, while dried reagents composed of silica and synthetic phospholipids were the most sensitive to heparin. CONCLUSION: Two reagents, namely aPTT-SP and SynthASIL both of which are based on synthetic phospholipids and silica, were identified as promising candidates for incorporation into point-of-care diagnostic device platforms as dried reagents.


Assuntos
Tempo de Tromboplastina Parcial/instrumentação , Kit de Reagentes para Diagnóstico/normas , Coagulação Sanguínea/efeitos dos fármacos , Heparina/sangue , Heparina/farmacologia , Humanos
20.
J Chromatogr A ; 977(1): 115-23, 2002 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-12456101

RESUMO

The research presented concerns segments of capillary chromatographic columns of different types (WCOT, SCOT, PLOT) used as traps for collection of samples of volatile organic analytes from a stream of air utilizing the equilibrium denudation technique. During the model experiments (utilizing standard mixtures), values of the partition coefficients (Kfs) were determined for volatile organic compounds frequently occurring as pollutants of atmospheric air (benzene, toluene, ethylbenzene, o-xylene, chlorobenzene). The conducted research demonstrated that the stationary phase film thickness did not affect the partition coefficient value. It was also proved that there is no dependence between the manner of applying the stationary phase in the column and the partition coefficient value.


Assuntos
Cromatografia Gasosa/instrumentação , Adsorção , Poluentes Atmosféricos/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...