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Find video protocols related to scientific articles indexed in Pubmed.
Antioxidant, antibacterial and cytotoxic potential of the ripe fruits of Solanum lycocarpum A. St. Hil. (Solanaceae).
Nat. Prod. Res.
PUBLISHED: 08-27-2014
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Ethanol extract (EE) and fractions obtained from the ripe fruits of Solanum lycocarpum were examined in order to determine their phenolic composition, antioxidant capacity, antibacterial activities and cytotoxic potential. High-performance liquid chromatography coupled with DAD analysis indicated that caffeic and chlorogenic acids were the main phenolic compounds present in the EE, dichloromethane (DCM) and ethyl acetate (Ac) fractions. The antioxidant activity assessed by the scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radical was significantly more pronounced for DCM and Ac fractions than that of the commercial antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT). EE and fractions exhibited selective antibacterial activity against Gram-positive bacteria, especially the hexane (Hex) and DCM fractions. EE and fractions exhibited low toxicity towards the LLC-MK2 cell line, especially the Hex, DCM and Ac fractions. This work provides the knowledge of phenolic composition in the extract and fractions from the ripe fruits of S. lycocarpum and their antioxidant, antibacterial and cytotoxic activities.
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Transmission line model analysis of transcription factors binding to oligoduplexes - differentiation of the effect of single nucleotide modifications.
Analyst
PUBLISHED: 06-24-2014
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Advanced impedance spectroscopy analysis based on the transmission line model (TLM) is explored as a novel QCM acoustic biosensing platform for the detection of the single point mutation effect on the binding of the transcription factors (TFs) to immobilized DNA oligoduplexes and the characterization of the protein-DNA mechanical properties.
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Effect of a Reduced-CHO Diet on the Rate of Perceived Exertion Curve During an Incremental Test.
Int J Sport Nutr Exerc Metab
PUBLISHED: 06-17-2014
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The objective of this study was to evaluate the effect of a reduced-carbohydrate (reduced-CHO) diet on the rate of perceived exertion (RPE) curve during an incremental test. Nine physically active men performed a progressive incremental test on a cycle ergometer (25 W·2 min-1) after 72 hr on either a control diet (60% CHO) or a reduced-CHO diet (30% CHO). Lactate and RPE thresholds were identified using the Dmax method (DmaxLa and DmaxRPE, respectively). Power output, heart rate and RPE scores in DmaxLa and DmaxRPE were similar between the diets and were not different from each other, regardless of the diet. Lactate values were consistently higher (p < .05) in the control diet compared with the reduced-CHO diet during power output after the lactate breakpoint; however, they were not accompanied by a proportional increase in RPE scores. These results suggest that DmaxRPE and DmaxLa are not dissociated after a short-period reduced-CHO diet, whereas the lactate values after the lactate threshold are reduced with a reduced-CHO diet, although they are not accompanied by alterations in RPE.
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An amorphous silicon photodiode microfluidic chip to detect nanomolar quantities of HIV-1 virion infectivity factor.
Analyst
PUBLISHED: 06-13-2014
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A hydrogenated amorphous silicon (a-Si:H) photosensor was explored for the quantitative detection of a HIV-1 virion infectivity factor (Vif) at a detection limit in the single nanomolar range. The a-Si:H photosensor was coupled with a microfluidic channel that was functionalized with a recombinant single chain variable fragment antibody. The biosensor selectively recognizes HIV-1 Vif from human cell extracts.
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Kinetic characterization of the retinoic X receptor binding to specific and unspecific DNA oligoduplexes with a quartz crystal microbalance.
Analyst
PUBLISHED: 05-15-2014
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Quartz Crystal Microbalance (QCM) biosensor technology was used to study the interaction of the DNA-binding domain (DBD) of the transcription factor RXR? with immobilized specific (DR1) and unspecific (DR1neg) DNA oligoduplexes. We identify the QCM sensor frequency at the susceptance minimum (fBmin) as a better measuring parameter, and we show that fBmin is proportional to the mass adsorbed at the sensor surface and is not influenced by interferences coming from viscoelastic variations of the adsorbed layers or buffers. This parameter was used to study the binding of RXR? to DNA and to calculate the association and dissociation kinetic constants of RXR?DBD-DR1 interaction. We show that RXR?DBD binds to DNA both as a monomer and as a homodimer, and that the mechanism of binding is salt dependent and occurs in two steps. The QCM biosensor data reveal that a high ionic strength buffer prevents the unspecific interactions and at a lower ionic strength the dissociation of RXR?DBD-DR1 occurs in two phases.
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Radiopacity, pH and antimicrobial activity of Portland cement associated with micro- and nanoparticles of zirconium oxide and niobium oxide.
Dent Mater J
PUBLISHED: 04-29-2014
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The aim of this study was to evaluate some properties of the calcium silicate materials Mineral Trioxide Aggregate (MTA) and Portland cement (PC) with microparticulated (micro) and nanoparticulated (nano) zirconium oxide (ZrO2) or niobium oxide (Nb2O5). The experimental materials: White PC (PC), MTA-Angelus(®) (MTA), PC+ZrO2micro, PC+ZrO2nano, PC+Nb2O5micro and PC+Nb2O5nano were submitted to radiopacity and pH evaluations. Furthermore, the antimicrobial activity against different microorganisms was assessed by agar diffusion test. MTA presented higher radiopacity than other materials. However, all materials except PC presented higher radiopacity than recommended by ISO/ADA. MTA promoted higher pH values in all analyzed periods (p?0.05). At the initial periods, PC and PC+ZrO2micro showed pH similar to MTA. All materials showed antimicrobial activity against the evaluated microorganisms. In conclusion, ZrO2 and Nb2O5 could be alternative radiopacifiers to be added to calcium silicate materials.
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Influence of gender on the risk of death and adverse events in patients with acute myocardial infarction undergoing pharmacoinvasive strategy.
J. Thromb. Thrombolysis
PUBLISHED: 03-28-2014
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Pharmacoinvasive treatment is an acceptable alternative for patients with ST-segment elevation myocardial infarction (STEMI) in developing countries. The present study evaluated the influence of gender on the risks of death and major adverse cardiovascular events (MACE) in this population. Seven municipal emergency rooms and the Emergency Mobile Healthcare Service in São Paulo treated STEMI patients with tenecteplase. The patients were subsequently transferred to a tertiary teaching hospital for early (<24 h) coronary angiography. A total of 469 patients were evaluated [329 men (70.1%)]. Compared to men, women had more advanced age (60.2 ± 12.3 vs. 56.5 ± 11 years; p = 0.002); lower body mass index (BMI; 25.85 ± 5.07 vs. 27.04 ± 4.26 kg/m2; p = 0.009); higher rates of hypertension (70.7 vs. 59.3%, p = 0.02); higher incidence of hypothyroidism (20.0 vs. 5.5%; p < 0.001), chronic renal failure (10.0 vs. 8.8%; p = 0.68), peripheral vascular disease (PVD; 19.3 vs. 4.3%; p = 0.03), and previous history of stroke (6.4 vs. 1.3%; p = 0.13); and higher thrombolysis in myocardial infarction risk scores (40.0 vs. 23.7%; p < 0.001). The overall in-hospital mortality and MACE rates for women versus men were 9.3 versus 4.9% (p = 0.07) and 12.9 versus 7.9% (p = 0.09), respectively. By multivariate analysis, diabetes (OR 4.15; 95% CI 1.86-9.25; p = 0.001), previous stroke (OR 4.81; 95% CI 1.49-15.52; p = 0.009), and hypothyroidism (OR 3.75; 95% CI 1.44-9.81; p = 0.007), were independent predictors of mortality, whereas diabetes (OR 2.05; 95% CI 1.03-4.06; p = 0.04), PVD (OR 2.38; 95% CI 0.88-6.43; p = 0.08), were predictors of MACE. In STEMI patients undergoing pharmacoinvasive strategy, mortality and MACE rates were twice as high in women; however, this was due to a higher prevalence of risk factors and not gender itself.
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Chitosan-alginate membranes accelerate wound healing.
J. Biomed. Mater. Res. Part B Appl. Biomater.
PUBLISHED: 03-27-2014
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The purpose of this study was to evaluate the efficacy of chitosan-alginate membrane to accelerate wound healing in experimental cutaneous wounds. Two wounds were performed in Wistar rats by punching (1.5 cm diameter), treated with membranes moistened with saline solution (CAM group) or with saline only (SL group). After 2, 7, 14, and 21 days of surgery, five rats of each group were euthanized and reepithelialization was evaluated. The wounds/scars were harvested for histological, flow cytometry, neutrophil infiltrate, and hydroxyproline analysis. CAM group presented higher inflammatory cells recruitment as compared to SL group on 2(nd) day. On the 7(th) day, CAM group showed higher CD11b(+) level and lower of neutrophils than SL group. The CAM group presented higher CD4(+) cells influx than SL group on 2(nd) day, but it decreased during the follow up and became lower on 14(th) and 21(st) days. Higher fibroplasia was noticed on days 7 and 14 as well as higher collagenesis on 21(st) in the CAM group in comparison to SL group. CAM group showed faster reepithelialization on 7(th) day than SL group, although similar in other days. In conclusion, chitosan-alginate membrane modulated the inflammatory phase, stimulated fibroplasia and collagenesis, accelerating wound healing process in rats. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2014.
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GFP-SCFV: Expression and possible applications as a tool for experimental investigations of atherosclerosis.
Biotechnol. Prog.
PUBLISHED: 03-07-2014
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Experimental studies on atherosclerosis are crucial for investigating its pathophysiology, defining new therapeutic targets, and developing new drugs and diagnostic tools. Thus, many imaging markers have been developed and introduced in experimental studies. The main advantage of these new tools is that they allow the noninvasive diagnosis of atherosclerotic vascular disease. Here, we describe the cloning, expression, purification, and stabilization of a chimeric protein specifically designed to probe cells and tissues for the presence of LDL(-), a relevant marker of atherosclerosis. The DNA sequence that encodes the anti-LDL(-) scFv, previously obtained from a hybridoma secreting an anti-LDL(-) monoclonal antibody, was inserted into the bacterial vector pET-28a(+) in tandem with a DNA sequence encoding GFP. The recombinant protein was expressed in high yields in E. coli as inclusion bodies. The applicability of GFP-scFv was assessed by ELISA, which determined its affinity for LDL(-) and confocal microscopy, that showed macrophage uptake of the protein along with LDL(-). In conclusion, our data suggest that the anti-LDL(-) GFP-scFv chimeric protein could be useful in studies on atherogenesis as well as for developing diagnostic tools for atherosclerosis. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1206-1213, 2014.
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Filling of simulated lateral canals with gutta percha or resilon when using thermomechanical compaction.
J Conserv Dent
PUBLISHED: 02-20-2014
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To evaluate the filling of simulated lateral canals with gutta-percha or Resilon when using thermomechanical compaction.
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Comparison of the effects of pulmonary rehabilitation with chest physical therapy on the levels of fibrinogen and albumin in patients with lung cancer awaiting lung resection: a randomized clinical trial.
BMC Pulm Med
PUBLISHED: 02-14-2014
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Systemic inflammation plays an important role in the initiation, promotion, and progression of lung carcinogenesis. In patients with non-small cell lung cancer (NSCLC), fibrinogen levels correlate with neoplasia. Here we compared the effects of pulmonary rehabilitation (PR) with chest physical therapy (CPT) on fibrinogen and albumin levels in patients with LC and previous inflammatory lung disease awaiting lung resection.
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Dysfunctional family environment in affected versus unaffected offspring of parents with bipolar disorder.
Aust N Z J Psychiatry
PUBLISHED: 10-09-2013
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Children of parents with bipolar disorder (BD) are at heightened risk for developing mood and other psychiatric disorders. We proposed to evaluate the environment of families with at least one parent with BD type I (BDF) with affected offspring (aBDF) and unaffected offspring (uBDF) compared with control families without a history of DSM-IV Axis I disorder (CF).
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Editorial: ESBES - European Society of Biochemical Engineering Sciences.
Biotechnol J
PUBLISHED: 06-07-2013
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The latest ESBES special issue on "Biochemical Engineering Sciences" is edited by Prof. Guilherme Ferreira (Chairman, ESBES) and Prof. Alois Jungbauer (co-Editor-in-Chief, Biotechnology Journal). This special issue comprises the latest research in biochemical engineering science presented at the 9(th) ESBES Conference held in Istanbul, Turkey in 2012.
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Acoustic detection of cell adhesion to a coated quartz crystal microbalance - implications for studying the biocompatibility of polymers.
Biotechnol J
PUBLISHED: 01-31-2013
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Biocompatibility of polymers is an important parameter for the successful application of polymers in tissue engineering. In this work, quartz crystal microbalance (QCM) devices were used to follow the adhesion of NIH 3T3 fibroblasts to QCM surfaces modified with fibronectin (FN) and poly-D-lysine (PDL). The variations in sensor resonant frequency (?f) and motional resistance (?R), monitored as the sensor signal, revealed that cell adhesion was favored in the PDL-coated QCMs. Fluorescence microscopy images of seeded cells showed more highly spread cells on the PDL substrate, which is consistent with the results of the QCM signals. The sensor signal was shown to be sensitive to extracellular matrix (ECM)-binding motifs. Ethylenediaminetetraacetic acid (EDTA) and soluble Gly-Arg-Gly-Asp-Ser (GRGDS) peptides were used to interfere with cell-ECM binding motifs onto FN-coated QCMs. The acquired acoustic signals successfully showed that in the presence of 30 mM EDTA or 1 mM GRGDS, cell adhesion is almost completely abolished due to the inhibition/blocking of integrin function by these compounds. The results presented here demonstrate the potential of the QCM sensor to study cell adhesion, to monitor the biocompatibility of polymers and materials, and to assess the effect of adhesion modulators. QCM sensors have great potential in tissue engineering applications, as QCM sensors are able to analyze the biocompatibility of surfaces and it has the added advantage of being able to evaluate, in situ and in real time, the effect of specific drugs/treatments on cells.
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Portuguese-language version of the COPD Assessment Test: validation for use in Brazil.
J Bras Pneumol
PUBLISHED: 01-22-2013
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To validate a Portuguese-language version of the COPD assessment test (CAT) for use in Brazil and to assess the reproducibility of this version.
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Immature dendritic cells generated from cryopreserved human monocytes show impaired ability to respond to LPS and to induce allogeneic lymphocyte proliferation.
PLoS ONE
PUBLISHED: 01-01-2013
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Dendritic cells play a key role in the immune system, in the sensing of foreign antigens and triggering of an adaptive immune response. Cryopreservation of human monocytes was investigated to understand its effect on differentiation into immature monocyte-derived dendritic cells (imdDCs), the response to inflammatory stimuli and the ability to induce allogeneic lymphocyte proliferation. Cryopreserved (crp)-monocytes were able to differentiate into imdDCs, albeit to a lesser extent than freshly (frh)-obtained monocytes. Furthermore, crp-imdDCs had lower rates of maturation and cytokine/chemokine secretion in response to LPS than frh-imdDCs. Lower expression of Toll-like receptor 4 (at 24 and 48 h) and higher susceptibility to apoptosis in crp-imdDCs than in fresh cells would account for the impaired maturation and cytokine/chemokine secretion observed. A mixed leukocyte reaction showed that lymphocyte proliferation was lower with crp-imdDCs than with frh-imdDCs. These findings suggested that the source of monocytes used to generate human imdDCs could influence the accuracy of results observed in studies of the immune response to pathogens, lymphocyte activation, vaccination and antigen sensing. It is not always possible to work with freshly isolated monocytes but the possible effects of freezing/thawing on the biology and responsiveness of imdDCs should be taken into account.
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Resistance to compression of weakened roots subjected to different root reconstruction protocols.
J Appl Oral Sci
PUBLISHED: 04-27-2011
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This study evaluated, in vitro, the fracture resistance of human non-vital teeth restored with different reconstruction protocols.
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pH, calcium ion release, and setting time of an experimental mineral trioxide aggregate-based root canal sealer.
J Endod
PUBLISHED: 02-17-2011
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An experimental mineral trioxide aggregate sealer (MTAS) has been developed for use as a root canal sealer. The aim of this study was to evaluate the setting time, pH, and calcium ion release of MTAS compared with white Portland cement (CPB-40; Votorantin Cimentos, Camargo Correa SA, Pedro Leopoldo, MG, Brazil), white MTA Angelus (MTA; Angelus, Londrina, PR, Brazil), and AH Plus (Dentsply DeTrey, Konstanz, Germany).
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Cell therapy for fibrotic interstitial pulmonary disease: experimental study.
Microsc. Res. Tech.
PUBLISHED: 01-04-2011
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Parte superior do formulário Digite um texto ou endereço de um site ou traduza um documento. The aim of this study is to evaluate the histological changes in lung parenchyma of pigs affected by interstitial lung disease induced after the infusion of bone marrow mononuclear cells (BMMCs). Ten female swines were submitted to pulmonary fibrosis induced by a single dose of intratracheal bleomicine sulfate. Animals were arranged into two groups: Group 1: induced-disease control and Group 2: cell therapy using BMMCs. Both groups were clinically evaluated for 180 days. High-resolution computed tomography (HRCT) was performed at 90 and 180 days. BMMC sampling was performed in cell therapy group at 90 days. Euthanasia was performed, and samples were collected for histology and immunohistochemistry. The 90-days HRCT demonstrated typical interstitial lesions in pulmonary parenchyma similarly to human disease. The 180-days HRCT in Group 1 demonstrated advanced stages of the disease when compared with Group 2. Immunohistochemistry analysis suggests the presence of pre-existent vessels and neoformed vessels as well as predominant young cells in the injured parenchyma of Group 2. Immunohistochemistry analysis suggests that cell therapy would promote a reconstructive response. Histology and HRCT analysis suggest a positive application of swine as a model for a bleomicine inducing of fibrotic interstitial pulmonary disease.
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Dynamical discrete/continuum linear response shells theory of solvation: convergence test for NH4+ and OH- ions in water solution using DFT and DFTB methods.
J Phys Chem B
PUBLISHED: 11-15-2010
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A new dynamical discrete/continuum solvation model was tested for NH(4)(+) and OH(-) ions in water solvent. The method is similar to continuum solvation models in a sense that the linear response approximation is used. However, different from pure continuum models, explicit solvent molecules are included in the inner shell, which allows adequate treatment of specific solute-solvent interactions present in the first solvation shell, the main drawback of continuum models. Molecular dynamics calculations coupled with SCC-DFTB method are used to generate the configurations of the solute in a box with 64 water molecules, while the interaction energies are calculated at the DFT level. We have tested the convergence of the method using a variable number of explicit water molecules and it was found that even a small number of waters (as low as 14) are able to produce converged values. Our results also point out that the Born model, often used for long-range correction, is not reliable and our method should be applied for more accurate calculations.
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CO(2) Laser Surgery and Prosthetic Management for the Treatment of Epulis Fissuratum.
ISRN Dent
PUBLISHED: 09-22-2010
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The aim of this study was to present a case report of the surgical removal of hyperplasia in the oral cavity, using carbon dioxide (CO(2)) laser radiation and rehabilitation with a complete denture. Epulis fissuratum occurs in complete denture patients, because a constant irritative action induces the mucosa to grow under poorly fitting dentures. These lesions must be removed, and to avoid a relapse, new complete dentures should be made to maintain healthy surgical tissues. The clinical sequence presented in this case shows a completely edentulous patient with epulis fissuratum on the lower alveolar ridge extending to the vestibular sulcus of the anterior region of mandible. Immediate complete dentures were made prior to the lesion removal with CO(2) laser radiation, providing satisfactory results in oral function and tissue health.
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Microcalorimetric and SAXS determination of PEO-SDS interactions: the effect of cosolutes formed by ions.
J Phys Chem B
PUBLISHED: 09-03-2010
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The effect of different ionic cosolutes (NaCl, Na(2)SO(4), Li(2)SO(4), NaSCN, Na(2)[Fe(CN)(5)NO], and Na(3)[Co(NO)(6)]) on the interaction between sodium dodecyl sulfate (SDS) and poly(ethylene oxide) (PEO) was examined by small-angle X-ray scattering (SAXS) and isothermal titration calorimetric techniques. The critical aggregation concentration values (cac), the saturation concentration (C(2)), the integral enthalpy change for aggregate formation (?H(agg)(int)) and the standard free energy change of micelle adsorption on the macromolecule chain (??G(agg)) were derived from the calorimetric titration curves. In the presence of 1.00 mmol L(-1) cosolute, no changes in the parameters were observed when compared with those obtained for SDS-PEO interactions in pure water. For NaCl, Na(2)SO(4), Li(2)SO(4), and NaSCN at 10.0 and 100 mmol L(-1), the cosolute presence lowered cac, increased C(2), and the PEO-SDS aggregate became more stable. In the presence of Na(2)[Fe(CN)(5)NO], the calorimetric titration curves changed drastically, showing a possible reduction in the PEO-SDS degree of interaction, possibility disrupting the formed nanostructure; however, the SAXS data confirmed, independent of the small energy observed, the presence of aggregates adsorbed on the polymer chain.
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Hidrocystoma: surgical management of cystic lesions of the eyelid.
An Bras Dermatol
PUBLISHED: 08-03-2010
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This report describes the case of a hidrocystoma of the eyelid and the surgical technique used in the therapeutical management of benign cystic lesions of the eyelids. Hidrocystomas are relatively common benign lesions of the eyelids, principally the lower eyelid. They are more common in females over thirty years of age. Diagnosis is clinical and when there is a single lesion, surgery is the treatment of choice. The surgical technique used should be described in greater detail, since it offers good esthetic results and a low risk of recurrence.
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Solvent capacity of different substances on gutta-percha and Resilon.
Braz Dent J
PUBLISHED: 05-14-2010
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The aim of this study was to evaluate the effectiveness of 3 solvents (eucalyptol, orange oil, and xylol) on 2 types of gutta-percha (conventional and thermoplastic) and Resilon. Specimens (10 mm diameter x 1 mm thick; n=7 per condition) were prepared and maintained at 37 degrees C for 48 h. Each specimen was weighed on a precision scale every 24 h until its mass was stable, at which time the initial mass was determined. Specimens (n=7) were then immersed in the solvent solutions and, after 48 h at 37 degrees C, they were reweighed at 24- h intervals, until stabilization (final mass). The difference between the final and the initial mass determined the solvent capacity of each solvent. Data were subjected to analysis of variance and Tukeys test at 5% significance level. The results demonstrated that xylol was the most effective, especially on conventional gutta-percha and Resilon (p<0.05). Eucalyptol and orange oil were more effective on thermoplastic gutta-percha than the other materials (p<0.05). It was concluded that all evaluated substances presented solvent action, but xylol was the most effective on both gutta-percha or Resilon.
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The airways and gastric contents in obese patients.
Rev Bras Anestesiol
PUBLISHED: 02-20-2010
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The objective of this study was to review the literature and to question the concept that obese patients should be considered as having a potential full stomach and, therefore, question how the airways, considered as of difficult access due to obesity, should be approached during anesthetic induction.
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Increased mortality and morbidity due to acute myocardial infarction in a public hospital, in Feira de Santana, Bahia.
Arq. Bras. Cardiol.
PUBLISHED: 10-20-2009
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Factors related to socioeconomic status and health care quality and management may influence mortality and morbidity rates due to acute myocardial infarction (AMI).
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Effect of light-curing method and indirect veneering materials on the Knoop hardness of a resin cement.
Braz Oral Res
PUBLISHED: 08-18-2009
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This study evaluated the Knoop hardness of a dual-cured resin cement (Rely-X ARC) activated solely by chemical reaction (control group) or by chemical / physical mode, light-cured through a 1.5 mm thick ceramic (HeraCeram) or composite (Artglass) disc. Light curing was carried out using conventional halogen light (XL2500) for 40 s (QTH); light emitting diodes (Ultrablue Is) for 40 s (LED); and Xenon plasma arc (Apollo 95E) for 3 s (PAC). Bovine incisors had their buccal face flattened and hybridized. On this surface a rubber mold (5 mm in diameter and 1 mm in height) was bulk filled with the resin cement. A polyester strip was seated for direct light curing or through the discs of veneering materials. After dry storage in the dark (24 h 37 degrees C), the samples (n = 5) were sectioned for hardness (KHN) measurements, taken in a microhardness tester (50 gF load 15 s). The data were statistically analyzed by ANOVA and Tukeys test (alpha = 0.05). The cement presented higher Knoop hardness values with Artglass for QTH and LED, compared to HeraCeram. The control group and the PAC/Artglass group showed lower hardness values compared to the groups light-cured with QTH and LED. PAC/HeraCeram resulted in the worst combination for cement hardness values.
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Acoustic wave biosensors: physical models and biological applications of quartz crystal microbalance.
Trends Biotechnol.
PUBLISHED: 06-26-2009
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Piezoelectric sensors are acoustic sensors that enable the selective and label-free detection of biological events in real time. These sensors generate acoustic waves and utilize measurements of the variation of the wave propagation properties as a signal for probing events at the sensor surface. Quartz crystal microbalance (QCM) devices, the most widespread acoustic resonators, allow the study of viscoelastic properties of matter, the adsorption of molecules, or the motility of living cells. In a tutorial-like approach, this review addresses the physical principles associated with the QCM, as well as the origin and effects of major interfering phenomena. Special attention is paid to the possibilities offered by QCM that go beyond microweighing, and important recent examples are presented.
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Aqueous two-phase systems: an efficient, environmentally safe and economically viable method for purification of natural dye carmine.
J Chromatogr A
PUBLISHED: 06-19-2009
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Partition of the natural dye carmine has been studied in aqueous two-phase systems prepared by mixing aqueous solutions of polymer or copolymer with aqueous salt solutions (Na(2)SO(4) and Li(2)SO(4)). The carmine dye partition coefficient was investigated as a function of system pH, polymer molar mass, hydrophobicity, system tie-line length and nature of the electrolyte. It has been observed that the carmine partition coefficient is highly dependent on the electrolyte nature and pH of the system, reaching values as high as 300, indicating the high potential of the two-phase extraction with ATPS in the purification of carmine dye. The partition relative order was Li(2)SO(4)"Na(2)SO(4). Carmine molecules were concentrated in the polymer-rich phase, indicating an enthalpic specific interaction between carmine and the pseudopolycation, which is formed by cation adsorption along the macromolecule chain. When the enthalpic carmine-pseudopolycation interaction decreases, entropic forces dominate the natural dye-transfer process, and the carmine partitioning coefficient decreases. The optimization of the extraction process was obtained by a central composite face-centered (CCF) design. The CCF design was used to evaluate the influence of Li(2)SO(4) and PEO 1500 concentration and of the pH on the partition coefficient of carmine. The conditions that maximize the partition of carmine into the top phase were determined to be high concentrations of PEO and Li(2)SO(4) and low pH values within the ranges studied.
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Piezoelectric biosensors assisted with electroacoustic impedance spectroscopy: a tool for accurate quantitative molecular recognition analysis.
J. Mol. Recognit.
PUBLISHED: 04-04-2009
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In this work, electroacoustic impedance analysis based on a modified Butterworth-Van Dyke (BVD) model is used to complement resonance frequency measurements of piezoelectric crystal sensors for the identification and removal of interfering signals. This approach enables the accurate use of the Sauerbrey correlation to establish a direct relationship between mass deposited at the sensor surface and measured frequency variations. Kinetic models can thus be evaluated and binding constants estimated directly from the measured data. We further demonstrate the usefulness of this approach by applying it to the study of the formation of 11-hydroxy-1-undecanothiol self-assembled monolayers (SAM) as well as to the binding of streptavidin to immobilized biotin. Kinetic and equilibrium parameters were estimated from transient analysis, adsorption isotherms, Scatchard and Hill plots obtained from the frequency data for both the alkanethiol and streptavidin films. This strategy based on electroacoustic impedance assisted quartz-crystal microbalance (QCM) biosensors is expected to be a major contribution for the use of these piezoelectric devices as a reliable and cheap detection system that can easily be integrated into analytical techniques.
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[Bougie].
Rev Bras Anestesiol
PUBLISHED: 01-31-2009
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Difficult airways require fast action by the anesthesiologist often requiring complementary devices to ensure patent airways. However, several of those devices are expensive and require training in order to be used. The bougie, a simple and disposable device can also be manufactured by the anesthesiologist, making it a low cost tool.
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Acoustic detection of cell adhesion on a quartz crystal microbalance.
Biotechnol. Appl. Biochem.
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An acoustic quartz crystal microbalance (QCM) was used to signal and follow the cell?adhesion process of epithelial cells [human embryonic kidney(HEK) 293T and cervical cancer (HeLa) and fibroblasts [African Green Monkey kidney cells (COS-7)] onto gold surfaces. Cells were applied on the sensor and grown under serum-free and serum-supplemented culture media. The sensor resonance frequency (?f) and motional resistance (?R) variations were measured during cell growth to monitor cell adhesion processes. Fingerprints of the adhesion processes, generated using the QCM signal, were found to be specific for each cell type while enabling the identification of the phases of the adhesion process. Under serum-free conditions, the deposition of HEK 293T and HeLa cells was characterized by a decrease of ?f with constant ?R, whereas for COS?7 cells, this initial deposition was signaled by variations of ?R at constant ?f. Toward the end of the adhesion process, fingerprints were characterized by a continuous increase of ?R consistent with the increase in viscoelasticity. The morphology of adherent cells was visualized by fluorescent microscopy, enabling the association of the cell morphology with QCM signals.
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Biocompatibility of intracanal medications based on calcium hydroxide.
ISRN Dent
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Objective. The aim of this study was to evaluate the rat subcutaneous tissue reaction to calcium hydroxide-based intracanal medicaments, UltraCal XS (calcium hydroxide, barium sulphate, aqueous matrix), Hydropast (calcium hydroxide, barium sulphate, and propyleneglycol), and Calen (Calcium hydroxide, zinc oxide, colophony, and polyethyleneglycol), used as a control. Methods. Forty-eight rats (Rattus Norvegicus Holtzman) were distributed in three groups: Calen, UltraCal XS, and Hydropast. Polyethylene tubes filled with one of the medicaments were implanted in the dorsal subcutaneous. After 7 and 30 days, the implants were removed and the specimens were fixed and embedded in paraffin. Morphological and quantitative analyses were carried out in the HE-stained sections. The numerical density of inflammatory cells in the capsule was evaluated and statistical analyses were performed (P ? 0.05). Results. At 7 days, all materials induced an inflammatory reaction in the subcutaneous tissue adjacent to the implants. In all groups, a significant reduction in the number of inflammatory cells and giant cells was verified in the period of 30 days. Conclusion. These results indicate that the calcium hydroxide-based medicaments evaluated present biocompatibility similar to Calen.
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Use of different extracts of coffee pulp for the production of bioethanol.
Appl. Biochem. Biotechnol.
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Coffee is one of the most important agricultural products in Brazil. More than 50 % of the coffee fruit is not used for the production of commercial green coffee and is therefore discarded, usually ending up in the environment. The goal of this work was to select an efficient process for obtaining coffee pulp extract and to evaluate the use of this extract in bioethanol production. The effects of heat treatment and trituration on the yield and composition of the extract were investigated by measuring the amounts of reducing sugars, starch, pectin, and phenolic compounds. The extraction process was most efficient at room temperature using grinding followed by pressing. Five different fermentation media were tested: sugarcane juice or molasses diluted with water or with coffee pulp extract and a medium with only coffee pulp extract. Batch fermentations were carried out at 30 °C for 24 h, and samples were taken to obtain measurements of the total reducing sugars, cell count, and ethanol concentration. The addition of coffee pulp extract did not influence the fermentation or yeast viability, and it can thus be mixed with sugarcane juice or molasses for the production of bioethanol, with a yield of approximately 70 g/L.
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Biocompatibility of an experimental MTA sealer implanted in the rat subcutaneous: quantitative and immunohistochemical evaluation.
J. Biomed. Mater. Res. Part B Appl. Biomater.
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The tissue reaction promoted by an experimental mineral trioxide aggregate sealer (MTAS) in the rat subcutaneous was evaluated by morphological and morphometric analyses. In the animals from each group (n = 20), polyethylene tubes filled with MTAS, Portland cement (PC) or MTA were implanted in the dorsal subcutaneous. In the control group, empty tubes were implanted. After 7, 14, 30, and 60 days, the specimens were fixed and embedded in paraffin. In the HE-stained sections, the numerical density of inflammatory cells (IC) in the capsule was evaluated and statistical analyses performed (p ? 0.05). The expression of osteopontin (OPN) was evaluated by immunohistochemistry. The von Kossa method for detection of calcified structures was also performed. A moderate inflammatory process in the capsule was seen in all groups, at 7 and 14 days. At 60 days, significant reduction in the number of IC was verified in comparison to initial periods; however, significant differences were not verified among the groups. OPN immunolabeling was observed in the fibroblasts cytoplasm of the capsule next to the implants. Structures von Kossa-positive were observed in the capsule adjacent to all materials implanted at 7, 14, and 30 days. The results strongly indicate that MTAS presents biocompatibility similarly to MTA and PC.
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A new intraoral device to facilitate preparation of the guide plane for removable dental prostheses.
Gen Dent
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This article presents a prototype of an intraoral device that facilitates preparation of parallel guide planes with accuracy and minimal occlusal divergence. The design of this device facilitates transfer of the desired path of insertion from the diagnostic cast to the mouth quickly and efficiently.
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Conformational and mechanical changes of DNA upon transcription factor binding detected by a QCM and transmission line model.
Analyst
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A novel quartz crystal microbalance (QCM) analytical method is developed based on the transmission line model (TLM) algorithm to analyze the binding of transcription factors (TFs) to immobilized DNA oligoduplexes. The method is used to characterize the mechanical properties of biological films through the estimation of the film dynamic shear moduli, G and G, and the film thickness. Using the Saccharomyces cerevisiae transcription factor Haa1 (Haa1DBD) as a biological model two sensors were prepared by immobilizing DNA oligoduplexes, one containing the Haa1 recognition element (HREwt) and another with a random sequence (HREneg) used as a negative control. The immobilization of DNA oligoduplexes was followed in real time and we show that DNA strands initially adsorb with low or non-tilting, laying flat close to the surface, which then lift-off the surface leading to final film tilting angles of 62.9° and 46.7° for HREwt and HREneg, respectively. Furthermore we show that the binding of Haa1DBD to HREwt leads to a more ordered and compact film, and forces a 31.7° bending of the immobilized HREwt oligoduplex. This work demonstrates the suitability of the QCM to monitor the specific binding of TFs to immobilized DNA sequences and provides an analytical methodology to study protein-DNA biophysics and kinetics.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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