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1.
Nature ; 623(7986): 397-405, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37914940

RESUMEN

Microglia are specialized brain-resident macrophages that arise from primitive macrophages colonizing the embryonic brain1. Microglia contribute to multiple aspects of brain development, but their precise roles in the early human brain remain poorly understood owing to limited access to relevant tissues2-6. The generation of brain organoids from human induced pluripotent stem cells recapitulates some key features of human embryonic brain development7-10. However, current approaches do not incorporate microglia or address their role in organoid maturation11-21. Here we generated microglia-sufficient brain organoids by coculturing brain organoids with primitive-like macrophages generated from the same human induced pluripotent stem cells (iMac)22. In organoid cocultures, iMac differentiated into cells with microglia-like phenotypes and functions (iMicro) and modulated neuronal progenitor cell (NPC) differentiation, limiting NPC proliferation and promoting axonogenesis. Mechanistically, iMicro contained high levels of PLIN2+ lipid droplets that exported cholesterol and its esters, which were taken up by NPCs in the organoids. We also detected PLIN2+ lipid droplet-loaded microglia in mouse and human embryonic brains. Overall, our approach substantially advances current human brain organoid approaches by incorporating microglial cells, as illustrated by the discovery of a key pathway of lipid-mediated crosstalk between microglia and NPCs that leads to improved neurogenesis.


Asunto(s)
Encéfalo , Colesterol , Células Madre Pluripotentes Inducidas , Microglía , Células-Madre Neurales , Neurogénesis , Organoides , Animales , Humanos , Ratones , Encéfalo/citología , Encéfalo/metabolismo , Diferenciación Celular , Células Madre Pluripotentes Inducidas/citología , Microglía/citología , Microglía/metabolismo , Organoides/citología , Organoides/metabolismo , Colesterol/metabolismo , Células-Madre Neurales/citología , Células-Madre Neurales/metabolismo , Axones , Proliferación Celular , Ésteres/metabolismo , Gotas Lipídicas/metabolismo
2.
Naturwissenschaften ; 110(5): 44, 2023 Sep 08.
Artículo en Inglés | MEDLINE | ID: mdl-37682350

RESUMEN

This study characterizes the osmophores and corolla traits in 18 species of Bignonieae Dumort., a Bignoniaceae tribe occurring in the Cerrado, a neotropical savanna in Brazil. To detect osmophore distribution, whole, newly opened flowers were immersed in Neutral Red Solution. Samples from the corolla tube and lobes were also fixed and analyzed micromorphologically, anatomically, and histochemically. The osmophores showed six markedly different distribution patterns that were not clearly associated with histological features. In most species, osmophores comprised papillose secretory epidermises and a few layers of subepidermal parenchyma. Starch grains, lipid droplets, and terpenes were detected in osmophores. An ornamented cuticle, cuticular folds, glandular and non-glandular trichomes, raised stomata and epicuticular wax granules are common traits in the species studied and may be useful in determining the taxonomy of the group. We found that 94% of the species visited by bees had papillose epidermises while the single hummingbird-pollinated species presented a flattened epidermis. Variations in osmophore pattern among species visited by bees, including variations within the same plant genus, are novel finding. Additionally, the Bignonieae species visited by bees presented a textured corolla surface, which has been reported as facilitating bee attachment and movement towards the floral resource. Future studies with a greater number of Bignonieae species and more detailed pollinator behavioral assays may help in the interpretation of the variations in corolla traits and functional relationships between flowers and pollinators.


Asunto(s)
Bignoniaceae , Animales , Abejas , Brasil , Flores , Fenotipo , Terpenos
3.
Polim Med ; 53(1): 37-46, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37260125

RESUMEN

BACKGROUND: Polymethylmethacrylate (PMMA) is the most used material for the manufacturing of eye prostheses. OBJECTIVES: To investigate the cytotoxicity of different cleaning agents for ocular prostheses on human conjunctival cells. MATERIAL AND METHODS: Six groups of specimens were created (saline, soap, 4% chlorhexidine, hydrogen peroxide, 1% triclosan, and citronella oil). Three specimens were made for each disinfectant at each disinfection period (1, 7, 15, 30, 60, and 90 days), totaling 108 specimens. Thus, the specimens were disinfected, with different disinfectants, for different periods of time. After each disinfection process, the specimens were washed with sterile distilled water. A human conjunctival cell line was grown on the acrylic resin specimens and then cytotoxicity tests (MTT and Neutral Red (NR)) were performed. A negative control (untreated cell cultures) and positive control (Tween 20) were created. Two-way analysis of variance (ANOVA) and Bonferroni test were performed (p < 0.05). RESULTS: For the MTT and NR tests, when there was a significant difference between the disinfectant and negative control, the disinfectant generated a significant reduction in cell proliferation most of the time. CONCLUSIONS: All reductions in cell proliferation caused by the disinfectants were clinically acceptable. All disinfectants tested in this study were found to be non-cytotoxic to human conjunctival cells.


Asunto(s)
Desinfectantes , Ojo Artificial , Humanos , Ensayo de Materiales , Desinfectantes/toxicidad , Clorhexidina , Desinfección
4.
World J Microbiol Biotechnol ; 38(2): 33, 2022 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-34989895

RESUMEN

The goal of this work is use a green chemistry route to synthesize selenium nanoparticles (SeNPs) that do not trigger oxidative stress, typical of metallic, oxide metallic and carbonaceous nanostructures, and supply the same beneficial effects as selenium nanostructures. SeNPs were synthesized using a radiolytic method involving irradiating a solution containing sodium selenite (Se4+) as the precursor in 1% Yeast extract, 2% Peptone, 2% Glucose (YPG) liquid medium with gamma-rays (60Cobalt). The method did not employ any hazardous reducing agents. Saccharomyces cerevisiae cells were incubated with 1 mM SeNPs for 24 h and/or then challenged with 400 Gy of ionizing radiation were assessed for viability and biomarkers of oxidative stress: lipid peroxidation, protein carbonylation, free radical generation, and total sulfhydryl content. Spherical SeNPs with variable diameters (from 100 to 200 nm) were formed after reactions of sodium selenite with hydrated electrons (eaq-) and hydrogen radicals (H·). Subsequent structural characterizations indicated an amorphous structure composed of elemental selenium (Se0). Compared to 1 mM selenite, SeNPs were considered safe and less toxic to Saccharomyces cerevisiae cells as did not elicit significant modifications in cell viability or oxidative stress parameters except for increased protein carbonylation. Furthermore, SeNPs treatment afforded some protection against ionizing radiation exposure. SeNPs produced using green chemistry attenuated the reactive oxygen species generation after in vitro ionizing radiation exposure opens up tremendous possibilities for radiosensitizer development.


Asunto(s)
Contención de Riesgos Biológicos , Nanopartículas/química , Radiación Ionizante , Ácido Selenioso/química , Selenio/química , Supervivencia Celular/efectos de los fármacos , Nanopartículas del Metal/química , Estrés Oxidativo , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/metabolismo , Selenito de Sodio , Compuestos de Sulfhidrilo
5.
Genet Mol Biol ; 44(1 Suppl 1): e20200199, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33729332

RESUMEN

Components of the complement system and atypical parameters of coagulation were reported in COVID-19 patients, as well as the exacerbation of the inflammation and coagulation activity. Mannose binding lectin (MBL)- associated serine proteases (MASPs) play an important role in viral recognition and subsequent activation of the lectin pathway of the complement system and blood coagulation, connecting both processes. Genetic variants of MASP1 and MASP2 genes are further associated with different levels and functional efficiency of their encoded proteins, modulating susceptibility and severity to diseases. Our review highlights the possible role of MASPs in SARS-COV-2 binding and activation of the lectin pathway and blood coagulation cascades, as well as their associations with comorbidities of COVID-19. MASP-1 and/or MASP-2 present an increased expression in patients with COVID-19 risk factors: diabetes, arterial hypertension and cardiovascular disease, chronic kidney disease, chronic obstructive pulmonary disease, and cerebrovascular disease. Based also on the positive results of COVID-19 patients with anti-MASP-2 antibody, we propose the use of MASPs as a possible biomarker of the progression of COVID-19 and the investigation of new treatment strategies taking into consideration the dual role of MASPs, including MASP inhibitors as promising therapeutic targets against COVID-19.

6.
Gen Dent ; 69(2): 52-55, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33661115

RESUMEN

A "gummy smile," considered to be exposure of more than 3.0 mm of gingival tissue during a forced smile, negatively affects smile esthetics. The present case series describes the clinical indications and technique for applying botulinum neurotoxin type A (BoNTA) to correct a gummy smile and assesses the outcomes and satisfaction levels of 3 patients. The patients were told about the risks and benefits of the procedure and advised that their gummy smile was likely to recur within 6 months posttreatment. After the exposed gingival tissue of the patients was measured with a ruler, photographs were taken, and the patients recorded their pretreatment level of satisfaction with their smile on a visual analog scale (VAS), the patients were treated with BoNTA. The BoNTA was diluted in 1 mL of sterile saline according to the manufacturer's instructions, and an extraoral point of application was marked 1 mm lateral to each of the patient's nasal wings, close to the insertion of the elevator muscles of the upper lip and the nasal wings. At each location, 4 U was injected by tilting the syringe 45° in relation to the skin. Fourteen days after treatment, the gingival tissue exposed during a smile was again measured with a ruler, new photographic records were taken, and the patients' level of satisfaction with the treatment and the esthetic result was determined. Repositioning of the upper lip was observed in all patients. No adverse effects or complaints were reported. All 3 patients reported that they were satisfied with the outcome and wanted to continue therapy with BoNTA as needed. The results of the reported cases suggest that the application of BoNTA constitutes a safe, effective treatment for the correction of gummy smile and is well accepted by patients. However, for the treatment to be successful, it is essential that clinicians master the facial topographic anatomy and the technique to be employed.


Asunto(s)
Estética Dental , Sonrisa , Encía , Gingivectomía , Humanos , Labio
7.
Gen Dent ; 69(5): 62-66, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34424215

RESUMEN

The aim of this study was to evaluate the influence of the geometry of the screwdriver-screw connection on the reverse torque of UCLA screws after repeated cycles of tightening and loosening in an implant-supported prosthesis. Thirty sets of external hex titanium implants, UCLA abutments, and UCLA abutment screws were divided into 3 experimental groups (n = 10). In the square group, the implant and UCLA abutment system were mounted in an upright position using a screw with a square screwdriver-screw connection. In the hexagonal group, the implant and UCLA abutment system were mounted in an upright position using a screw with a hexagonal screwdriver-screw connection. In the hexalobular group, the implant and UCLA abutment system were mounted at 70° using a dynamic UCLA abutment and screw with a hexalobular screwdriver-screw connection. Ten alternating torque-reverse torque cycles were applied to each screw using a screwdriver fixed at the end of a digital torque meter. The screws with a square connection resulted in less loss of reverse torque than the other types. Screws with a hexagonal connection showed a statistically significant loss of torque initially but remained constant for the remaining cycles. For the screws with a hexalobular connection, the loss of torque was greater, and substantial deformation of the plastic in the microstructure was noted. The screwdriver-screw connection geometry had a direct influence on the reverse torque of UCLA screws, and the initial reverse torque of the abutment screws with a square connection was greater than that of the hexagonal and hexalobular designs.


Asunto(s)
Pilares Dentales , Implantes Dentales , Tornillos Óseos , Análisis del Estrés Dental , Humanos , Torque
8.
Anal Biochem ; 597: 113666, 2020 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-32142760

RESUMEN

Metabolomic studies are essential to identify and quantify key metabolites in biological systems. Analysis of amino acids (AA) is very important in target metabolomics studies. Chromatographic methods are used to support metabolite determinations. Therefore, this work presents analysis of 17 AA in Saccharomyces cerevisiae cells (a useful model in the study of cancer metabolism) exposed to sodium selenite and gamma radiation. An improved GC/MS method using propyl chloroformate/propanol as derivatizing reagent was applied to AA determinations. The method exhibited good linearity in the range of 0.08-600.00 mg L-1; limits of determination from 0.04 to 1.60 mg L-1; limits of quantification from 0.08 to 2.76 mg L-1; repeatability ranging from 1.9 to 11.4 %; and precision ranging from 2.8 to 13.8 %. The correlations between selenite/gamma radiation with AA profile was investigated to establish candidates for cancer biomarkers. The analyses of yeast cultures found high concentrations of amino acids, such as Alanine, Serine, Glutamate, and Lysine, which might be associated with the development of metabolic adaptations of cancer based on its high demand for biomass and energy, found both in this model and neoplastic cells.


Asunto(s)
Aminoácidos/metabolismo , Rayos gamma , Metabolómica , Saccharomyces cerevisiae/metabolismo , Selenio/química , Aminoácidos/análisis , Saccharomyces cerevisiae/citología , Selenio/metabolismo
9.
J Biochem Mol Toxicol ; 34(1): e22413, 2020 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-31714634

RESUMEN

Hepatic diseases leading to fibrosis affect millions of individuals worldwide and are a major public health challenge. Although, there have been many advances in understanding hepatic fibrogenesis, an effective therapy remains elusive. Studies focus primarily on activation of the hepatic stellate cells (HSCs), the principal fibrogenic cells in the liver; however, fewer numbers of studies have examined molecular mechanisms that deactivate HSC, controlling the profibrogenic phenotype. In the present study, we evaluated cellular and molecular actions of the chemical triclosan (TCS) in reverting activated HSCs to a quiesced phenotype. We demonstrated that the inhibition of the enzyme fatty acid synthase by TCS in activated HSCs promotes survival of the cells and triggers cellular and molecular changes that promote cellular phenotypic reversion, offering potentially new therapeutic directions.


Asunto(s)
Inhibidores de la Síntesis de Ácidos Grasos/farmacología , Células Estrelladas Hepáticas/efectos de los fármacos , Triclosán/farmacología , Línea Celular , Supervivencia Celular/efectos de los fármacos , Ácido Graso Sintasas/antagonistas & inhibidores , Células Estrelladas Hepáticas/citología , Humanos
10.
An Acad Bras Cienc ; 92(suppl 2): e20181002, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33084750

RESUMEN

The structural complexity of galls depends on species-specific interaction driven by the galling taxa. However, the host plant and environment stressors can impose limits on gall developmental patterns and impact the establishment of gall morphology. Herein, we employed qualitative and quantitative approaches in order to elucidate how cell divisions, elongation patterns, and tissue organization are determinant for the development of intralaminar gall morphology induced by Pseudophacopteron longicaudatum Malenovský, Burckhardt, Queiroz, Isaias & Oliveira (Hemiptera: Psylloidea: Phacopteronidae) on leaves of Aspidosperma tomentosum Mart. (Apocynaceae). In addition, we aimed to determine which anatomical process can discriminate the stages of gall development, plus, examine the histochemical and cytological profiles of the galls. The differentiated structures, mainly abaxial epidermis and spongy parenchyma, are associated with gall closure, with hyperplastic events concentrated in the young phase of the galls. Thus, epidermis and spongy parenchyma hypertrophy and are responsible for the determination of the nymphal chamber formation and gall shape. The mature galls do not differentiate into a typical nutritive cells and do not develop a histochemical gradient in their tissues. The cytological features of galls such as plastoglobules and multivesicular bodies are related to ROS scavenging mechanisms due the high oxidative stress.


Asunto(s)
Apocynaceae , Aspidosperma , Hemípteros , Animales , Hojas de la Planta , Tumores de Planta
11.
J Clin Pediatr Dent ; 44(5): 342-347, 2020 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-33181845

RESUMEN

OBJECTIVE: The present study investigated the erosive potential of children's mouthrinses on glass ionomer cement (GIC) samples after simulated toothbrushing. STUDY DESIGN: Forty round-shaped samples of GIC were divided into 3 groups: G1- cetylpyridinium chloride, G2- xylitol and triclosan and G3-Malva sylvestris and xylitol and G4-distilled water as a control group. Prior to the main tests, the samples were submitted to the surface roughness measurement (Ra) and weight analysis (W). Afterward, they were brushed twice day (2× / day) for 15 days and immersed in mouthrinses after the last daily brushing. The final surface roughness (R2) and weight (W2) were determined after completing the tooth brushing-mouth rinsing cycles and the real increase in roughness (ΔRa) and real weight loss (ΔW) were calculated. In addition, stereoscopic images taken at 30× magnification. The data was analyzed by one-way ANOVA and Tukey-test post hoc tests for intergroup comparison and the T-test for dependent samples (α = 0.05). RESULTS: Only group G2 showed increased in roughness ΔRa (1.53 ± 0.94) whereas ΔW values were not significant. However, evident cracks and voids were verified for all tested children's rinses. CONCLUSION: Thus, children's mouthrinse containing xylitol / triclosan increased the GIC roughness, especially when associated with brushing.


Asunto(s)
Antisépticos Bucales , Cepillado Dental , Niño , Cementos de Ionómero Vítreo , Humanos , Ensayo de Materiales , Propiedades de Superficie
12.
Cell Biol Int ; 43(3): 333-343, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30468282

RESUMEN

Hepatic fibrosis and its end-stage cirrhosis have increased worldwide, and, despite all the efforts, no successful therapy is available. More recently, the heptapeptide angiotensin-(1-7) [ang-(1-7)] was reported to be able to modulate liver fibrosis and even steatosis; however, the molecular bases of these effects are not clear. In this study, we investigated the overexpression of the microRNA-1254 in the human hepatic stellate cell line LX-2, based on the effect of the heptapeptide in such cells, previously, demonstrated by our research group. In addition, this miRNA was chosen based on the identification of putative binding site of this small molecule in the mRNA sequences of different molecular connectors of the AKT/ PI3K pathway, which is modulated by the heptapeptide and connects to the control of several cellular mechanisms, including proliferation, survival, migration, and even liver fibrogenesis. The results revealed an innovative function of the miR-1254 in controlling SMAD3 and pro-fibrosing elements as well as the wound healing response in LX-2, attenuating the scaring repair of the injured tissue. The combined findings provide useful information for future studies on the controlling of hepatic fibrogenesis.


Asunto(s)
Cirrosis Hepática/genética , Cirrosis Hepática/patología , MicroARNs/metabolismo , Proteína smad3/metabolismo , Cicatrización de Heridas , Secuencia de Bases , Línea Celular , Humanos , MicroARNs/genética , Transcripción Genética
13.
Ecotoxicol Environ Saf ; 166: 223-230, 2018 Dec 30.
Artículo en Inglés | MEDLINE | ID: mdl-30269018

RESUMEN

Microcystin-LR (MCLR) is a toxin mainly produced by Microcystis aeruginosa, cyanobacteria most commonly found in eutrophic environments. Cyanobacteria blooms have affected Salto Grande reservoir (Americana, State of São Paulo/Brazil) for several decades, often observed during periods of drought. In this study, the genotoxic effects of MCLR (95% purity) and water samples contaminated by this toxin were evaluated during cyanobacteria bloom using assays with the test organism Allium cepa. The results showed genotoxic action for pure microcystin and cytotoxic, genotoxic and mutagenic action for water samples collected during flowering. Chromosomal aberration assays have shown that MCLR induces chromosomal breaks that persist in the daughter cells as MN. Therefore, it is possible to infer a clastogenic action for this toxin. The MCLR present in the environmental samples was shown to be more cytogenotoxic for the cells than the different concentrations tested in this study with the pure substance. This amplified toxic action can be related to a synergistic effect between the MCLR and other compounds present in the environmental samples. The genotoxicity studies with MCLR show inconsistent and inconclusive results, so this toxin needs to be better investigated in order to obtain further information about the action mode of it is on the biological system.


Asunto(s)
Microcistinas/toxicidad , Mutágenos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Brasil , Rotura Cromosómica , Daño del ADN , Toxinas Marinas , Microcystis/crecimiento & desarrollo , Cebollas/efectos de los fármacos , Cebollas/genética , Agua/química
14.
Phytochem Anal ; 29(1): 69-76, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28877378

RESUMEN

INTRODUCTION: Species of the genera Psychotria and Palicourea are sources of indole alkaloids, however, the distribution of alkaloids within the plants is not known. Analysing the spatial distribution using desorption electrospray ionisation mass spectrometry imaging (DESI-MSI) has become attractive due to its simplicity and high selectivity compared to traditional histochemical techniques. OBJECTIVES: To apply DESI-MSI to visualise the alkaloid distribution on the leaf surface of Psychotria prunifolia and Palicourea coriacea and to compare the distributions with HPLC-MS and histochemical analyses. METHODOLOGY: Based upon previous structure elucidation studies, four alkaloids targeted in this study were identified using high resolution mass spectrometry by direct infusion of plant extracts, and their distributions were imaged by DESI-MSI via tissue imprints on a porous Teflon surface. Relative quantitation of the four alkaloids was obtained by HPLC-MS/MS analysis performed using multiple-reaction monitoring (MRM) mode on a triple quadrupole mass spectrometer. RESULTS: Alkaloids showed distinct distributions on the leaf surfaces. Prunifoleine was mainly present in the midrib, while 10-hydroxyisodeppeaninol was concentrated close to the petiole; a uniform distribution of 10-hydroxyantirhine was observed in the whole leaf of Psychotria prunifolia. The imprinted image from the Palicourea coriacea leaf also showed a homogeneous distribution of calycanthine throughout the leaf surface. CONCLUSION: Different distributions were found for three alkaloids in Psychotria prunifolia, and the distributions found by MSI were in complete accordance with HPLC-MS analysis and histochemical results. The DESI-MSI technique was therefore demonstrated to provide reliable information about the spatial distribution of metabolites in plants. Copyright © 2017 John Wiley & Sons, Ltd.


Asunto(s)
Alcaloides/química , Hojas de la Planta/química , Psychotria/química , Rubiaceae/química , Espectrometría de Masa por Ionización de Electrospray , Cromatografía Liquida , Espectrometría de Masas en Tándem
15.
An Acad Bras Cienc ; 88(1): 309-22, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26982621

RESUMEN

Trichogonia cinerea is endemic to Brazil and occurs in areas of cerrado and campo rupestre. In this study, we characterized the glandular and non-glandular trichomes on the aerial parts of this species, determined the principal events in the development of the former, and identified the main constituents of the volatile oil produced in its aerial organs. Fully expanded leaves, internodes, florets, involucral bracts, and stem apices were used for the characterization of trichomes. Leaves, internodes, florets, and involucral bracts were examined by light microscopy and scanning electron microscopy, whereas stem apices were examined only by light microscopy. Branches in the reproductive phase were used for the extraction and determination of the composition of the volatile oil. The species has three types of glandular trichomes, biseriate vesicular, biseriate pedunculate, and multicellular uniseriate, which secrete volatile oils and phenolic compounds. The major components identified in the volatile oil were 3,5-muuroladiene (39.56%) and butylated hydroxytoluene (13.07%).


Asunto(s)
Asteraceae/química , Aceites Volátiles/análisis , Tricomas/anatomía & histología , Asteraceae/clasificación , Asteraceae/citología , Inmunohistoquímica , Microscopía Electrónica de Rastreo
16.
J Contemp Dent Pract ; 17(2): 160-4, 2016 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-27207006

RESUMEN

OBJECTIVE: To evaluate the dimensional changes, reproduction of details, and surface roughness of a type IV cast and a resin used to fabricate dental models. MATERIALS AND METHODS: Two commercial brands of materials were evaluated: a type IV synthetic cast (Fuji Rock) and a polyol resin (Novox). Twenty samples were obtained from polyvinyl siloxane molds that reproduced the surface of a metal master model standardized according to the American National Standards Institute/American Dental Association specification no. 19. The materials were used according to the manufacturer's instructions and divided into two groups (n = 10). Each mold was photographed immediately after molding and 1 hour after molding. The obtained models were also photographed and measurements were obtained by using Image J software. The paired t-test was used to compare the molding materials and one-way analysis of variance (ANOVA) was used to compare the dimensional changes between the groups at a significance level of 5%. RESULTS: Statistically significant differences were observed between the models fabricated with the polyol resin and type IV synthetic cast with regard to reproduction of surface details, surface roughness, and dimensional stability (p < 0.05), with the resin providing superior surface detail reproduction and greater dimensional accuracy. CONCLUSION: The polyol resin exhibited superior behavior regarding detail reproduction, surface roughness, and dimensional change compared with the type IV synthetic cast.


Asunto(s)
Modelos Dentales , Polímeros , Resinas Sintéticas , Análisis de Varianza , Materiales Dentales , Ensayo de Materiales , Polivinilos , Siloxanos , Propiedades de Superficie
17.
J Contemp Dent Pract ; 17(3): 235-9, 2016 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-27207204

RESUMEN

OBJECTIVE: The aim of this study was to evaluate the association between tooth loss and the signs and symptoms of temporomandibular disorders (TMDs). MATERIALS AND METHODS: One hundred fifty patients with an average age of 49.2 (±14.06) years were divided into three groups (n = 50/group) according to the degree of tooth loss: GI (dentate -control), GII (edentulous), GIII (partially dentate). After performing anamnesis and clinical examination, a questionnaire was used, so that the patients could fill in information on signs and symptoms of TMD. After analyzing this information, it was possible to classify the degree of severity of TMD. As age is a confounding variable to the level of TMD, an analysis of covariance (ANCOVA) was used to check for differences in the degree of TMD between groups (covariate = age). A post hoc test (Bonferroni) was performed to compare the groups two by two (5% significance level). RESULTS: The mean level of TMD according to the groups was GI - 1.95; GII - 2.15; GIII - 2.55. There were significant differences between the study groups (p > 0.05). A post hoc test (Bonferroni) confirmed the difference between edentulous patients and the other groups. CONCLUSION: The tooth loss is directly related to the signs and symptoms of TMD. The degree of TMD was significantly higher in edentulous patients.


Asunto(s)
Trastornos de la Articulación Temporomandibular/etiología , Pérdida de Diente/complicaciones , Humanos , Persona de Mediana Edad , Encuestas y Cuestionarios
18.
J Prosthodont ; 24(2): 172-7, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24981971

RESUMEN

Upper lip cancers are infrequent lesions, being aggressive unless diagnosed and treated early. After the surgical resection, maxillofacial defects require special care in rehabilitation. This article describes the maxillofacial rehabilitation of an edentulous patient diagnosed with upper lip squamous cell carcinoma. The treatment consisted of a large amount of upper lip and nose tissue resection, followed by chemoradiotherapy. After the first surgical healing, zygoma implants were inserted in a two-step procedure. The maxillary and nasal prostheses were installed and fixed by a titanium framework. After 6 years follow-up, no recurrences were observed, and the patient did not develop metastases. Tissues around implants were in good health, and the prostheses remained well-fitted. The use of implant-retained prostheses improved the quality of life, and the patient was extremely satisfied with the final result. The implant-retained prostheses are well accepted by the patient, improving comfort and safety during function while recovering her esthetic apperance.


Asunto(s)
Implantes Dentales , Labio/cirugía , Nariz/cirugía , Cigoma/cirugía , Proceso Alveolar/cirugía , Femenino , Humanos , Maxilar/cirugía , Persona de Mediana Edad
19.
J Contemp Dent Pract ; 16(6): 468-73, 2015 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-26323450

RESUMEN

AIM: The aim of this study was to investigate the influence of calcium hydroxide dressing on the filling of simulated lateral canals by different obturation techniques. MATERIALS AND METHODS: Sixty single-root-premolars were instrumented. Simulated lateral canals were drilled on each third of the roots. The teeth were divided into four groups: no dressing and obturation by lateral condensation technique (G1), dressing with calcium hydroxide and obturation by lateral condensation technique (G2), no dressing and obturation by hybrid technique (G3) and, dressing with calcium hydroxide and obturation by hybrid technique (G4). The teeth were maintained at 37°C in 100% humidity for 7 days, and obturation techniques were performed. Radiographs were taken and filled or unfilled lateral canals were counted. Data were analyzed using analysis of variance (ANOVA) followed by Tukey's test (a = 5%). RESULTS: The hybrid technique filled large number of lateral canals as compared to lateral condensation technique, regardless the use of intracanal medication (p < 0.05). Calcium hydroxide decreased the number of lateral canals filled for both lateral and hybrid techniques (p < 0.05). Significant differences were observed when comparing the number of filled and unfilled lateral canals in the same root third of each group (p < 0.05). CONCLUSION: Regardless the obturation technique, calcium hydroxide dressing reduced the penetration of filling material in simulated lateral canals. CLINICAL SIGNIFICANCE: The persistence of calcium hydroxide residues reduces the penetration of filling material in simulated lateral canals, possibly representing a potential cause of failure in the future.


Asunto(s)
Hidróxido de Calcio/química , Irrigantes del Conducto Radicular/química , Obturación del Conducto Radicular/métodos , Análisis de Varianza , Cavidad Pulpar , Endodoncia/métodos , Humanos , Ensayo de Materiales/métodos , Modelos Anatómicos , Materiales de Obturación del Conducto Radicular/química , Preparación del Conducto Radicular/métodos
20.
Microb Pathog ; 69-70: 39-44, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24685701

RESUMEN

Candida albicans colonizes sites with different environmental pH. However, it is unclear how these conditions can interfere on biofilms. This study aimed to evaluate the influence of environmental pH on behavior of C. albicans regarding its structure, virulence and susceptibility to fluconazole (FLZ). Minimal inhibitory concentration, minimal fungicidal concentration and time kill were used to evaluate the susceptibility to FLZ in planktonic cells under three pH values (4.0, 5.5, 7.0). These pH values were used for biofilms analysis. C. albicans ATCC 90028 was developed on poly(methlymethacrylate) resin for 48 h. Then, 2.56 µg/mL of FLZ was added to experimental groups for 24 h, and biofilms were analyzed by cell quantification, bioactivity, secretion of proteinases and phospholipases and structure. All data were analyzed by two-way ANOVA, followed by Tukey's test (α = 0.05). For planktonic cells, changes in environmental pH decreased the susceptibility to FLZ. C. albicans biofilms developed at pH 5.5 showed higher cell counts, bioactivity, bio-volume, average thickness and roughness coefficient (p < 0.05). In contrast, the presence of FLZ at pH 4.0 did not influence the structural parameters (p > 0.05), but increased secretion of proteinase and phospholipase (p < 0.05). Within the conditions studied, it was shown that environmental pH modulates the structure, virulence and susceptibility of C. albicans to FLZ.


Asunto(s)
Antifúngicos/farmacología , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Candida albicans/efectos de los fármacos , Candida albicans/fisiología , Fluconazol/farmacología , Recuento de Colonia Microbiana , Concentración de Iones de Hidrógeno , Pruebas de Sensibilidad Microbiana , Viabilidad Microbiana/efectos de los fármacos
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