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1.
Dent Mater ; 35(11): 1568-1575, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31500903

RESUMO

OBJECTIVE: To quantify the volumetric polymerization shrinkage (VPS) of different conventional and bulk fill resin composites, through micro-computed tomography (µCT), and qualitative comparison of gap formation through optical coherence tomography (OCT). METHODS: Box-shaped class I cavities were prepared in 30 third-molars and divided into 5 groups (n=6): G1- Filtek Z100 (Z100); G2- Tetric Evoceram Bulk Fill (TEC); G3- Tetric EvoFlow Bulk fill (TEF); G4- Filtek Bulk fill (FBU); and G5- Filtek Bulk fill Flowable (FBF). All groups were treated with Adper Single Bond Plus adhesive and light cured (Bluephase 20i). Each tooth was scanned three times using a µCT apparatus: after cavity preparation (empty scan); after cavity filling (uncured scan) and after light curing of the restorations (cured scan). The µCT images were imported into a three-dimensional rendering software, and volumetric polymerization shrinkage percentage was calculated (%) for each sample. In the same images, interfacial gaps in the pulpal floor were qualitatively evaluated. After µCT evaluation, the pulpal floor from each tooth was polished until a thin tooth structure was obtained and OCT images were obtained by scanning the pulpal portion. Gap formation was observed and qualitatively compared to the µCT images. RESULTS: VPS means ranged from 2.31 to 3.96% for the studied resin composites. The bulk fill materials, either high viscosity or flowable, were not statistically different from each other (p>0.05). The conventional resin composite Z100 presented statistically higher VPS than both high viscosity bulk fill materials studied (p<0.05), although it was statistically similar to the flowable bulk fill materials studied (p>0.05). Both µCT and OCT methodologies enabled gap formation visualization, and images from both technologies could be associated. Gap formation was mostly observed for G1-Z100, G4-FBU, and G5-FBF. VPS% and pulpal gap formation could not be completely associated with each other for all groups and samples. Voids were observed in most of the resin composite fillings, and most VPS were observed in the occlusal area of the samples. SIGNIFICANCE: Volumetric polymerization shrinkage was material-dependent, although bulk fill materials did not differ from each other. Both µCT and OCT enabled interfacial pulpal gap formation visualization. VPS and gap formation cannot be completely associated with one another.


Assuntos
Cárie Dentária , Tomografia de Coerência Óptica , Resinas Compostas , Humanos , Teste de Materiais , Polimerização , Microtomografia por Raio-X
2.
J Biomed Mater Res B Appl Biomater ; 107(5): 1320-1328, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30199603

RESUMO

The study evaluated the effects of a Supercritical CO2 (scCO2 ) on a commercially available decellularized/delipidized naturally derived porcine pericardium collagen membrane, Vitala®. The Vitala® and scCO2 treated experimental membranes were evaluated for guided tissue regeneration (GTR) of periodontal tissue in class III furcation defects utilizing a dog model. Physical material characterization was performed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The in vivo portion of the study was allocated to three-time points (6, 12, and 24-weeks) using standardized class III furcation defects created in the upper second and third premolars. The experimental defects (n = 5) were covered with either a collagen membrane (positive control), scCO2 -treated collagen membrane (experimental) or no membrane (negative control). Following sacrifice, histologic serial sections were performed from cervical to apical for morphologic/morphometric evaluation. Morphometric evaluation was carried out by ranking the presence of collagen membrane, amount of bone formation within the defect site and inflammatory cell infiltrate content. SEM showed the experimental scCO2 -treated membrane to have a similar gross fibrous appearance and chemical structure in comparison to the Vitala® Collagen membrane. A significant increase in membrane thickness was noted in the scCO2 -treated membranes (366 ± 54 µm) vs non-treated membranes (265 ± 75 µm). TGA and DSC spectra indicated no significant qualitative differences between the two membranes. For the in vivo results, both membranes indicated significantly greater amounts of newly formed bone (scCO2 : 2.85 ± 1.1; Vitala®: 2.80 ± 1.0) within the covered defects relative to uncovered controls (0.8 ± 0.27) at 24 weeks. Both membrane types gradually degraded as time elapsed in vivo from 6 to 12 weeks, and presented nearly complete resorption at 24 weeks. The inflammatory infiltrate at regions in proximity with the membranes was commensurate with healthy tissue levels from 6 weeks in vivo on, and periodontal ligament regeneration onset was detected at 12 weeks in vivo. The effect of the supplementary scCO2 treatment step on the collagen membrane was demonstrated to be biocompatible, allowing for the infiltration of cells and degradation over time. The treated membranes presented similar performance in GTR to non-treated samples in Class III furcation lesions. Defects treated without membranes failed to achieve regeneration of the native periodontium. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1320-1328, 2019.


Assuntos
Dióxido de Carbono/química , Colágeno , Membranas Artificiais , Pericárdio/química , Ligamento Periodontal , Regeneração , Animais , Colágeno/química , Colágeno/farmacologia , Cães , Ligamento Periodontal/lesões , Ligamento Periodontal/patologia , Ligamento Periodontal/fisiologia , Suínos
3.
Dent Mater J ; 37(3): 393-399, 2018 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-29375091

RESUMO

The understanding of cuspal deflection and volumetric shrinkage of resin composites is necessary to assess and improve the placement techniques of resin-based materials. The aim of this study was to investigate the cuspal deflection and its relationship with volumetric polymerization shrinkage of different bulk-fill resin composites. The investigation was conducted using non-contact phase microscopy and micro-computed tomography. Thirty custom-milled aluminum blocks were fabricated for microscopy analysis and thirty-six tooth models with standardized Class I cavities were used for micro-computed tomography analysis. Results showed that high-viscosity composites present higher cuspal deflection compared to bulk-fill composites. The filler loading of resin composites seems to have an effect on cusp deflection, since the higher the filler content percentage, the higher the cusp deflection. On the other hand, it seems to have an opposite effect on volumetric shrinkage, since higher filler loadings produced lower volumetric shrinkage percentages.


Assuntos
Resinas Compostas/química , Microscopia/métodos , Microtomografia por Raio-X , Dente Pré-Molar , Infiltração Dentária , Adaptação Marginal Dentária , Materiais Dentários/química , Restauração Dentária Permanente/métodos , Cura Luminosa de Adesivos Dentários , Teste de Materiais , Polimerização , Viscosidade
4.
J Prosthet Dent ; 119(1): 103-107, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28461048

RESUMO

STATEMENT OF PROBLEM: Few studies have investigated the voids and gaps produced during the cementation of fiber posts using different techniques. PURPOSE: The purpose of this study was to evaluate and quantify void and gap area formations of different fiber post cementation techniques using microcomputed tomography (µCT). MATERIAL AND METHODS: Standardized endodontically treated acrylic resin roots (N=24) were divided into 4 groups (n=6) according to different fiber posts cemented with the resin cement (FB); fiber posts relined with composite resin followed by cementation (FBR); fiber posts cemented using an ultrasonic device (FBU); and fiber posts relined with composite resin and cemented using an ultrasonic device (FBRU). Each specimen was scanned twice using micro-computed tomography (µCT; empty root, followed by after fiber post cementation). Digital imaging and communications in medicine (DICOM) files were transferred into 3-dimensional (3D) reconstruction software for analysis. Void volume in the cementation system and gap area formation were evaluated; quantitative and qualitative analyses were performed. The data were analyzed using 2-way ANOVA and the Tukey honest significant difference post hoc test (α=.05). RESULTS: FBR showed a lower percentage of voids than obtained for FB (P<.05). Groups FB, FBU, and FBRU did not show significant difference in void formation (P>.05). No significant differences were found in gap area formations among the experimental groups (P>.05). CONCLUSIONS: The use of a composite resin to reline the fiber post significantly decreased the void formation in the cementation procedure when no ultrasonic device was used. The use of an ultrasonic device did not decrease the percentage of void or gap formation for any technique evaluated.


Assuntos
Cimentação/métodos , Resinas Compostas , Dentina/diagnóstico por imagem , Técnica para Retentor Intrarradicular , Raiz Dentária/diagnóstico por imagem , Microtomografia por Raio-X , Humanos , Técnicas In Vitro
5.
Dent Mater J ; 37(1): 33-39, 2018 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-29081446

RESUMO

This study evaluated the influence of different light-curing modes on the volumetric polymerization shrinkage and degree of conversion of a composite resin at different locations using micro-computed tomography and Fourier transform infrared spectroscopy (FTIR). Specimens were divided into 4 groups based on the light-curing mode used (Bluephase 20i): 1 -High (1,200 mW/cm2); 2 -Low (650 mW/cm2); 3 -Soft-start (650-1,200 mW/cm2); and 4 -Turbo (2,000 mW/cm2). Degree of conversion was calculated by the measurement of the peak absorbance height of the uncured and cured materials at the specific wavenumbers, and was performed by FTIR 48 h after curing resin samples. Degree of conversion was analyzed using two-way ANOVA. No significant differences were observed independent of the region of the restoration investigated (p>0.05). Different curing modes did not influence volumetric shrinkage neither degree of conversion of class I composite resin restorations.


Assuntos
Resinas Compostas/química , Cura Luminosa de Adesivos Dentários/métodos , Microtomografia por Raio-X , Resinas Acrílicas , Lâmpadas de Polimerização Dentária , Análise do Estresse Dentário , Dureza , Hemisferectomia , Teste de Materiais , Polimerização , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície
6.
J Prosthet Dent ; 117(6): 784-791, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27836148

RESUMO

STATEMENT OF PROBLEM: Few studies have investigated the volumetric polymerization shrinkage and film thickness of the different cementation techniques used to cement veneers. PURPOSE: The purpose of this in vitro study was to evaluate the volumetric polymerization shrinkage (VS) and film thickness (FT) of various cementation techniques through 3-dimensional (3D) microcomputed tomography (µCT). MATERIAL AND METHODS: Forty-eight artificial plastic maxillary central incisors with standard preparations for veneers were provided by a mannequin manufacturer (P-Oclusal) and used as testing models with the manufacturer's plastic veneers. They were divided into 8 groups (n=6): RelyX Veneer + Scotchbond Universal (RV+SBU); Variolink Esthetic LC+Adhese Universal (VE+ADU); Filtek Supreme Ultra Flowable + Scotchbond Universal (FF+SBU); IPS Empress Direct Flow + Adhese Universal (IEF+ADU); Filtek Supreme Ultra Universal + Scotchbond Universal (FS+SBU); IPS Empress Direct + Adhese Universal (IED+ADU); Preheated Filtek Supreme Ultra Universal + Scotchbond Universal (PHF+SBU); and Preheated IPS Empress Direct + Adhese Universal (PHI+ADU). Specimens were scanned before and after polymerization using a µCT apparatus (mCT 40; Scanco Medical AG), and the resulting files were imported and analyzed with 3D rendering software to calculate the VS and FT. Collected data from both the VS and FT were submitted to 1-way ANOVA (α=.05). RESULTS: VE+ADU had the lowest volumetric shrinkage (1.03%), which was not significantly different from RV+SBU, FF+SBU or IEF+ADU (P>.05). The highest volumetric shrinkage was observed for FS+SBU (2.44%), which was not significantly different from RV+SBU, IED+ADU, PHF+SBU, or PHI+ADU (P>.05). Group RV+SBU did not differ statistically from the remaining groups (P>.05). Film thickness evaluation revealed the lowest values for RV+SBU, VE+ADU, FF+SBU, and IEF+ADU, with an average between groups of 0.17 mm; these groups were significantly different from FS+SBU, IED+ADU, PHF+SBU, and PHI+ADU (P>.05), with an average of 0.31 mm. CONCLUSIONS: Both the VS and the FT of direct restorative composite resins were higher than those of veneer cements and flowable composite resins, whether preheated or not preheated.


Assuntos
Cimentos Dentários , Facetas Dentárias , Radiografia Dentária , Microtomografia por Raio-X , Colagem Dentária/métodos , Cimentos Dentários/uso terapêutico , Adaptação Marginal Dentária , Humanos , Imageamento Tridimensional , Técnicas In Vitro , Polimerização , Radiografia Dentária/métodos , Microtomografia por Raio-X/métodos
7.
Acta sci., Biol. sci ; 38(3): 273-282, jul.-set. 2016. ilus, tab
Artigo em Inglês | LILACS | ID: biblio-827260

RESUMO

The essential oil from the fresh leaves of Kyllinga pumila (Michx) was obtained by hydrodistillation and characterized by gas chromatography-mass spectrometry (GC-MS). Twenty-eight volatile compounds were identified, major constituents of the oil were Methyl E,E-10,11-epoxyfarnesoate (43.8%), ß-elemene (12.5%), Z-caryophyllene (11.3%), germacrene D (7.1%) and E-caryophyllene (5.6%). Repellent and fumigant activities of the oil against Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), were done using the area preference method. Additionally, we studied their antioxidant and phytotoxic effects. Essential oils exhibited a dose- dependent repellent activity, with values 90% at the applied concentration (0.01%), for both two and four hour's exposure. Essential oil from K. pumila showed 92% mortality at 500 µL L-1 air against T. castaneum on 24 hours of exposure. The value LC50 was 153.4 µL L-1. With moderate selective phytotoxic effects on L. perenne root growth (±70% inhibition). Kyllinga pumila shows high antioxidant potential (91.5%), an effect that is comparable with ascorbic acid (92.9%) used as a standard. The results indicated that K. pumila essential oil could be a promising alternative to new natural antioxidants, repellents, and biocides.


O óleo essencial das folhas frescas de Kyllinga pumila Michx., foi obtido por hidrodestilação e caracterizado por cromatografia gasosa acoplada a espectrometria de massas (CG-EM). O constituinte majoritário do óleo foi Metil E,E-10,11-epoxifarnesoato (43,8%), ß-elemeno (12,5%), Z-caryophylleno (11,3%), germacreno D (7,1%), E-caryophylleno (5,6%). A atividade repelente e fumigante do óleo frente à Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) foi determinada pelo método da área de preferencia. Também, foi estudado os efeitos antiferrugens e fitotóxicos. Óleos essenciais exibiram uma atividade repelente dependente da dose, com valores de 90% na concentração aplicada (0,01%), tanto para duas e quatro horas de exposição. O óleo essencial de K. pumila mostrou mortalidade de 92% a 500 µL L-1 ar frente à T. castananeum, em 24 horas de exposição. O valor LC50 foi 153,4 µL L-1. Com efeitos fitotóxicos seletivos moderado sobre o crescimento da raíz de L. perenne (± 70% de inibição). Kyllinga pumila mostra um elevado potencial antioxidante (92%), um efeito que é comparável com ácido ascórbico (95%) usado como padrão. Os resultados indicaram que o óleo essencial K. pumila poderia ser uma alternativa promissora para novos antioxidantes, repelentes e biocidas naturais.


Assuntos
Tribolium , Óleos Voláteis , Fumigação , Cyperaceae , Repelentes de Insetos
8.
ASUNCIÒN; IPS/UCA; 30122010. 70 p. graf.
Monografia em Espanhol | LILACS, BDNPAR | ID: biblio-1018612

RESUMO

El sìndrome coronario agudo sin elevaciòn del segmento ST constituye una causa frecuente de consulta en los servicios de urgencia y de hospitalizaciòn en las unidades de cuidados intensivos o de reanimaciòn..


Assuntos
Traumatismos Cardíacos/complicações , Traumatismos Cardíacos/genética , Traumatismos Cardíacos/sangue , Paraguai
9.
Biocell ; 34(1): 45-52, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20506630

RESUMO

The present paper deals with the ultrastructure of zoospores produced by the plasmodiophorid Maullinia ectocarpii, living in the marine algal host Ectocarpus siliculosus. The zoospores described here are very similar to secondary zoospores of Polymyxa graminis and Phagomyxa sp. (the latter an algal endoparasite, also). Our results indicate that M. ectocarpii produces two types of plasmodia, and suggest that is a species with a complete life cycle, as it is known for all the Plasmodiophormycota that have been studied. Sporogenic and sporangial plasmodia produce, respectively, primary zoospores with parallel flagella within thick walled resting sporangia, and secondary zoospores with opposite flagella within thin walled sporangia.


Assuntos
Plasmodioforídeos/ultraestrutura , Flagelos/ultraestrutura , Microscopia Eletrônica de Transmissão , Phaeophyceae/parasitologia , Plasmodioforídeos/parasitologia , Esporos de Protozoários/ultraestrutura
10.
Biocell ; 34(1): 45-52, Apr. 2010. ilus
Artigo em Inglês | LILACS | ID: lil-595049

RESUMO

The present paper deals with the ultrastructure of zoospores produced by the plasmodiophorid Maullinia ectocarpii, living in the marine algal host Ectocarpus siliculosus. The zoospores described here are very similar to secondary zoospores of Polymyxa graminis and Phagomyxa sp. (the latter an algal endoparasite, also). Our results indicate that M. ectocarpii produces two types of plasmodia, and suggest that is a species with a complete life cycle, as it is known for all the Plasmodiophormycota that have been studied. Sporogenic and sporangial plasmodia produce, respectively, primary zoospores with parallel flagella within thick walled resting sporangia, and secondary zoospores with opposite flagella within thin walled sporangia.


Assuntos
Esporos de Protozoários/ultraestrutura , Flagelos/ultraestrutura , Phaeophyceae/parasitologia , Microscopia Eletrônica de Transmissão
11.
Stem Cells Dev ; 19(1): 39-46, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19485710

RESUMO

The success rate of human embryonic stem cell (hESC) derivation depends on both culture conditions and embryo quality and is routinely determined by morphological criteria. However, high incidence of chromosomal abnormality even in high-grade cleavage embryos from in vitro fertilization (IVF) patients suggests that the morphological grade of supernumerary embryos obtained from IVF clinics may not be a good prediction factor for successful hESC derivation. We show here that from one donor under identical derivation conditions 12 karyotypically abnormal post-bioptic embryos did not yield hESC lines, whereas two out of four normal embryos did. This suggests that the capacity of embryos to give rise to hESC line is likely to be influenced by their genetic status.


Assuntos
Linhagem Celular , Embrião de Mamíferos/citologia , Células-Tronco Embrionárias/fisiologia , Proliferação de Células , Separação Celular/métodos , Células Cultivadas , Aberrações Cromossômicas/embriologia , Eficiência , Técnicas de Cultura Embrionária , Destinação do Embrião , Embrião de Mamíferos/metabolismo , Desenvolvimento Embrionário/genética , Células-Tronco Embrionárias/metabolismo , Fertilização in vitro , Genótipo , Humanos , Cariotipagem
12.
Stem Cells Dev ; 18(9): 1343-50, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19222349

RESUMO

In a continuous effort to improve the generation of therapeutic grade human embryonic stem cell (hESC) lines, we focused on preserving developmental capacity of the embryos, minimizing the exposure to xenomaterials, increasing derivation efficacy, and reducing the complexity of the derivation procedure. In this study, we describe an improved method for efficient derivation of hESC lines from blastomeres of biopsied embryos. Our protocol substituted feeder cells of mouse origin with human foreskin fibroblasts (HFFs), limited serum exposure of cells to formation of the initial outgrowth, and increased derivation efficacy from 12.5% (one hESC line out of 13 biopsies) to 50% (3 out of 6 biopsies) by using early population doubling (PD) HFFs. In addition, it eliminated a need for embryo-blastomere coculture, thus reducing the complexity of the culture and enabling continued development of the biopsied embryo under optimal conditions. All derived lines maintained normal karyotype and expressed totipotent phenotype including the ability to differentiate into trophectoderm and all three germ layers.


Assuntos
Blastômeros/citologia , Células-Tronco Embrionárias/citologia , Fibroblastos/citologia , Fosfatase Alcalina/metabolismo , Técnicas de Cultura de Células/métodos , Linhagem Celular , Técnicas de Cocultura , Células-Tronco Embrionárias/efeitos dos fármacos , Células-Tronco Embrionárias/metabolismo , Prepúcio do Pênis/citologia , Humanos , Imuno-Histoquímica , Cariotipagem , Masculino , Fator 3 de Transcrição de Octâmero/genética , Fator 3 de Transcrição de Octâmero/metabolismo , Reprodutibilidade dos Testes , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células-Tronco Totipotentes/citologia , Células-Tronco Totipotentes/metabolismo , Xenobióticos/farmacologia
13.
Sex Transm Dis ; 34(12): 1019-24, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18080353

RESUMO

GOAL: To determine type-specific seroprevalence of herpes simplex viruses (HSV-1 and HSV-2) and HSV-2 risk factors. STUDY DESIGN: Six-hundred fifty eight middle-aged control women (hospital-based in 4 of 6 countries) from a multicenter cervical cancer case-control study participated from 1985 to 1997. Type-specific serum IgG antibodies against HSV-1 and HSV-2 were detected with Western Blot. RESULTS: HSV-1 seroprevalence was 89% to 100% everywhere except Thailand (51%). HSV-2 seroprevalence ranged from 9% (Spain) to 57% (Colombia), and was independently associated with having >or=2 lifetime sexual partners overall [Odds ratio (OR), 2.1; 95% confidence interval (CI) 2.5-3.1], and in Morocco (OR, 2.7; 95% CI, 1.2-6.1) and Thailand (OR, 4.4; 95% CI, 1.3-15.4), and with being unmarried in Colombia, Peru, Spain, but not significantly in Mali. Women whose male partner's sexual debut was

Assuntos
Anticorpos Antivirais/sangue , Herpes Genital/epidemiologia , Herpesvirus Humano 2/imunologia , Estudos de Casos e Controles , Colômbia/epidemiologia , Feminino , Herpes Genital/virologia , Herpesvirus Humano 1/imunologia , Humanos , Mali/epidemiologia , Pessoa de Meia-Idade , Marrocos/epidemiologia , Peru/epidemiologia , Fatores de Risco , Estudos Soroepidemiológicos , Comportamento Sexual , Parceiros Sexuais , Espanha/epidemiologia , Especificidade da Espécie , Tailândia/epidemiologia
14.
Rev Gastroenterol Peru ; 26(4): 377-85, 2006.
Artigo em Espanhol | MEDLINE | ID: mdl-17211488

RESUMO

Gastric cancer continues to be one of the most common malignant neoplasias in the world. Despite the decreasing incidence of this disease in developed countries, Eastern Europe and Latin America show the highest incidences. It accounted for 8.6% of all new cases of cancer in 2002. In Peru it has increased between 1990 and 1997 amounting to 24.3/100000 in men and 17.6/100000 in women, during the last period studied, thus it is considered a high risk area. Mortality: it is still the leading cause of death for both sexes, in men it is 19.3/100000 and in women 14.2/100000. Incidence is directly proportional to the place of origin in Metropolitan Lima, a city of almost 8 million inhabitants, and the districts with the highest incidences are Puente Piedra and Lince followed by Villa El Salvador, El Augustino, Breña and Rimac among others. These are districts with medium-low socioeconomic levels, whereas the lowest incidences are found in districts with high socioeconomic levels, such as San Isidro and Miraflores, among others.


Assuntos
Neoplasias Gástricas/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Peru/epidemiologia , Prevalência , Sistema de Registros
15.
Biocell ; 30(3): 491-6, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17375469

RESUMO

Nonspecific acid phosphatases are a group of enzymes whose activity increases the availability of exogenous and endogenous orthophosphate either through extra- or intracellular hydrolysis of phosphate compounds. Our study demonstrates the activity of acid phosphatases in the filamentous freshwater alga Stigeoclonium tenue. These enzymes were detected following a cerium-based method in which cerium was used as an orthophosphate-capture reagent. In thalli from S. tenue from the natural environment, acid phosphatases were found in the longitudinal cell wall, plasmalemma, and vacuole. In thalli from Bold's Basal Medium culture, these enzymes were found mainly in the plasmalemma; they were scarce in the cell wall. In the thalli grown in phosphate-enriched culture medium, enzymes were found only in the plasmalemma. The low availability of orthophosphate in the medium seems to induce the transport of these enzymes to the cell wall. Its abundance, on the contrary, seems to attenuate this response without affecting the localization of acid phosphatases in the plasmalemma.


Assuntos
Fosfatase Ácida/análise , Proteínas de Algas/análise , Clorófitas/enzimologia , Clorófitas/ultraestrutura , Argentina , Parede Celular/química , Clorófitas/química , Água Doce/microbiologia
16.
Fertil Steril ; 83(5): 1517-29, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15866593

RESUMO

OBJECTIVE: To derive new human embryonic stem cell (hESC) lines on pathogen-free human placental fibroblast feeders under serum-free conditions. Because the embryo develops in close contact with extraembryonic membranes, we hypothesized that placental mesenchyme might replicate the stem cell niche in situ. DESIGN: We isolated and characterized human placental fibroblast lines from individual donors and tested their ability to support growth of federally registered hESC lines. Moreover, we performed extensive pathogen testing to ensure their suitability as feeders for the derivation of therapy-grade hESCs. RESULT(S): Human placental fibroblasts were comparable or superior to mouse embryo fibroblasts as hESC feeders. We used these qualified placental fibroblasts to derive two new hESC lines in knockout Dulbecco's modified Eagle's medium with serum-free 20% knockout serum replacement. The cells, which had a normal karyotype, were grown for more than 25 passages, expressed markers of stemness including Oct-3/4, Tra 1-60, Tra 1-80, and SSEA-4, exhibited high telomerase activity, and differentiated in vitro and in vivo into cells derived from all three germ layers, confirming their pluripotency. Additionally, newly derived hESCs were adapted to growth on a human placental laminin substrate in a defined medium. CONCLUSION(S): To our knowledge, this is the first report of hESC derivation in the absence of serum on qualified pathogen-free human feeders.


Assuntos
Diferenciação Celular , Meios de Cultura Livres de Soro/farmacologia , Fibroblastos/citologia , Placenta/citologia , Técnicas de Cultura de Tecidos/métodos , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Feminino , Fibroblastos/efeitos dos fármacos , Fibroblastos/fisiologia , Humanos , Placenta/efeitos dos fármacos , Placenta/fisiologia , Gravidez , Células-Tronco/citologia , Células-Tronco/efeitos dos fármacos , Células-Tronco/fisiologia
17.
Am J Med Genet A ; 130A(4): 354-64, 2004 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-15389712

RESUMO

Aneuploid cells in the placenta are associated with poor pregnancy outcomes, but the mechanisms are unclear. Here, we examined the cytotrophoblast (CTB) differentiation pathway that leads to uterine invasion in pregnancies complicated by trisomy 21 (T21) as compared with their normal counterparts. Surprisingly, we observed a wide spectrum of T21 effects. Morphologically, some samples appeared near normal, while others had extensive fibrinoid deposition and apoptosis of CTBs at the maternal-fetal interface (confirmed by TUNEL labeling). At a molecular level, the cells' expression of stage-specific molecules was variably misregulated. At one end of the spectrum, samples with less apoptosis had relatively normal staining patterns. At the other end, samples with extensive apoptosis showed significantly decreased staining for these antigens. Additional studies confirmed that the effects we observed had functional consequences, because the cells exhibited marked phenotypic alterations in vitro, including a large increase in MMP-9 production, which distinguishes the effects of T21 on CTBs from those of preeclampsia. The morphologic, phenotypic, and functional differences among CTBs from pregnancies complicated by T21 illustrate the importance of the interplay between fetal/placental genotype and maternal influences on pregnancy outcome. Furthermore, our data may explain why a significant number of these pregnancies end in spontaneous abortion while others survive to term.


Assuntos
Diferenciação Celular/genética , Síndrome de Down/genética , Síndrome de Down/fisiopatologia , Regulação da Expressão Gênica no Desenvolvimento , Trofoblastos/citologia , Aborto Espontâneo , Antígenos/análise , Apoptose , Estudos de Casos e Controles , Implantação do Embrião , Genótipo , Humanos , Fenótipo , Placentação
18.
Biocell ; 27(2): 181-7, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-14510236

RESUMO

The present study analyzed several characters of the red seaweed Gymnogongrus torulosus, such as cellular structure of the thallus, cuticle, pit plug and cell wall ultrastructure, and morphology of some organelles like plastids, Golgi bodies and mitochondria. Also, anomalous chloroplasts with thylakoid disorganization were found in medullary cells. The significance of this thylakoid disposition is still unclear. This is one of the first studies focused on the fine structure of a red alga recorded in Argentina.


Assuntos
Organelas/ultraestrutura , Rodófitas/ultraestrutura , Alga Marinha/ultraestrutura , Parede Celular/fisiologia , Parede Celular/ultraestrutura , Cloroplastos/fisiologia , Cloroplastos/ultraestrutura , Complexo de Golgi/fisiologia , Complexo de Golgi/ultraestrutura , Microscopia Eletrônica , Mitocôndrias/fisiologia , Mitocôndrias/ultraestrutura , Organelas/fisiologia , Plastídeos/fisiologia , Plastídeos/ultraestrutura , Rodófitas/fisiologia , Alga Marinha/fisiologia , Tilacoides/fisiologia , Tilacoides/ultraestrutura
19.
J Phycol ; 36(4): 714-722, 2000 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-29542153

RESUMO

The ultrastructure of zoospores of Asterococcus superbus (Cienk.) Scherffel was studied to provide ultrastructural data relevant to the systematic position of the genus. Our results demonstrated that the motile cells of A. superbus were similar to those of the tetrasporalean algae, such as Tetraspora sp. and Tetrasporidium javanicum Moebius. The flagellar apparatus of A. superbus had the same clock-wise orientation of basal bodies and the V-shaped alignment of basal bodies as Tetraspora cylindrica (Wahlb.) Ag. and T. lubrica (Roth) Ag., but differed by having rhizoplasts. The motile cells of A. superbus displayed chlamydomonadal ultrastructure, similar to Chlamydomonas reinhardtii Dangeard, including the absolute configuration of the flagellar apparatus. The pyrenoid matrix in A. superbus, however, showed a large lateral invagination occupied by chloroplast stroma, a characteristic that has never been observed in Chlorophyta.

20.
Rev. méd. Inst. Peru. Segur. Soc ; 7(1): 31-4, ene.-mar. 1998. tab
Artigo em Espanhol | LILACS | ID: lil-227685

RESUMO

Se presenta diez casos de hiperemesis gravídica tratadas con corticoides, en gestantes dentro del primer trimestre del embarazo, cuyas edades oscilaron entre los 23 y 35 años. Como antecedentes estas pacientes habían presentado crisis anteriores de esta sintomatología, siendo tratadas con antieméticos (dimenhidrinato, metoclorpramida y domperidona), antihistamínicos e hidratación; de acuerdo a las normas clásica s, con resultados variables. Nosotros hemos utilizado corticoides asociándolos al tratamiento hídrico, tanto por vía oral como endovenosa, habiendo conseguido resultados entre muy buenos a excelentes en el 90 por ciento de los casos, dentro de las 72 horas de iniciado el tratamiento.


Assuntos
Humanos , Feminino , Gravidez , Corticosteroides/uso terapêutico , Hiperêmese Gravídica/terapia
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