Navegando por Palavras-chave "riboflavin"
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- ItemSomente MetadadadosCharacterization of Rabbit Corneas Subjected to Stromal Stiffening by the Acai Extract (Euterpe oleracea)(Taylor & Francis Inc, 2017) Bersanetti, Patricia A. [UNIFESP]; Bueno, Tatiane L. N. [UNIFESP]; Morandim-Giannetti, Andreia de A.; Nogueira, Regina F. [UNIFESP]; Matos, Jivaldo R.; Schor, Paulo [UNIFESP]Purpose: In this study, we characterized rabbit corneas subjected to corneal cross-linking (CXL) with acai extract compared with a riboflavin photo-stimulated procedure. Materials and Methods: The corneas of the slaughterhouse rabbits were divided into three groups: control, consisting of untreated corneal samples
- ItemAcesso aberto (Open Access)Cross-linking e segmento de anel corneano intraestromal(Conselho Brasileiro de Oftalmologia, 2011-02-01) Renesto, Adimara da Candelaria [UNIFESP]; Sartori, Marta [UNIFESP]; Campos, Mauro Silveira de Queiroz [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Corneal cross-linking is a procedure used for stabilizing the cornea in patients with progressive keratoconus by increasing corneal rigidity, and it is also used in corneal inflammatory melting process. The intrastromal corneal ring segments act by flatting the center of the cornea. Originally designed for the correction of mild myopia, the segments are now being used for reduction of keratoconus in order to improve the uncorrected visual acuity, the best spectacle corrected visual acuity, to allow good tolerance to the use of contact lenses and delay the need for corneal grafting procedures. The present text presents a review of corneal cross-linking and insertion of intrastromal corneal ring segments, emphasizing their indications, results and complications related until now.
- ItemSomente MetadadadosDietary riboflavin restriction and chronic hemin administration does not alter brain function in rats: The importance of vitamin homeostasis in the brain(New Century Health Publishers, Llc, 2007-11-01) DalPai, Janise [UNIFESP]; Borges, Andrea Aurélio [UNIFESP]; Grassl, Christian [UNIFESP]; Favero Filho, Luiz Antonio [UNIFESP]; Xavier, Gilberto Fernando [UNIFESP]; Junqueira, Virginia Berlanga Campos [UNIFESP]; Lopes, Antonio Carlos [UNIFESP]; Coimbra, Cicero Galli [UNIFESP]; Sinigaglia-Coimbra, Rita [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Vitamin B2 deficiency associated with normal dietary intake has been reported inpatients with Parkinson disease (PD), suggesting impaired absorption of this micronutrient. Elevated red meat consumption was thought to contribute as a triggering factor, as the catabolism of hemin (a neurotoxic substance) requires vitamin B2 (Coimbra &Junqueira, 2003). This study tested this hypothesis by verifying the effects of dietary riboflavin restriction associated with hemin administration on rat brain. After 8 months of riboflavin restriction, riboflavin deficiency with or without oral administration of hemin (assessed by erythrocyte glutathion ereductase activity) did not impair motor function or spatial learning; neither altered the volume of substantia nigra or brain concentrations of total glutathione. Partial dietary restriction of riboflavin may failed to induce oxidative stress in the rat brain and dopaminergic degeneration in the rat substantia nigra as suggested to occur in humans by Coimbra & Junqueita, (2003), possibly due to an intact mechanism of nutritional privilege that preserves riboflavin content in the normal rat brain during deficiency states. Contrastingly, polymorphic enzymes or receptors involved in the human cellular uptake of ribofiavin may conceivably impair the transport of this micronutrient not only through the intestinal wall and renal tubules, but also in the brain of PD patients, there by annulling the nutritional privilege of the nervous system.
- ItemSomente MetadadadosEffect of Collagen Cross-linking in Stromal Fibril Organization in Edematous Human Corneas(Lippincott Williams & Wilkins, 2010-07-01) Bottos, Katia Mantovani [UNIFESP]; Hofling-Lima, Ana Luisa [UNIFESP]; Barbosa, Manuela C. [UNIFESP]; Barbosa, Jose Bonifacio [UNIFESP]; Dreyfuss, Juliana L. [UNIFESP]; Schor, Paulo [UNIFESP]; Nader, Helena B. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Purpose: To assess structural stromal modifications after riboflavin and UV-A exposure in edematous human corneas.Method: Fourteen eyes with corneal edema were enrolled in the study. in the cross-linking (CXL) group, 7 corneal buttons were obtained from 6 patients who underwent penetrating keratoplasty (PK) 7-90 days after the CXL treatment. the control group was composed of 7 corneal buttons with bullous keratopathy. After the PK, stromal modifications were investigated using immunofluorescence in all corneal grafts. All patients had at least 3 months of corneal edema and were in the eye bank list waiting for keratoplasty.Results: All corneas in the treated group showed a pronounced lamellar zone of collagen fibers highly organized in the anterior stroma, but there was not complete homogeneity between the samples. Corneas with advanced disease and stromal fibrosis were less compacted than ones with mild disease severity. Similarly, those ones that underwent PK 3 months after CXL also showed a decreased effect compared with those with a reduced time between the CXL and the PK. DAPI staining demonstrated a complete fragmentation of keratocytes nuclei in the anterior stroma in all treated corneas, which were absent in the control group.Conclusions: Our study showed an immediate effect of CXL with a limited long-term sustainability. Cross-linked corneas had a pronounced anterior zone of organized collagen fibers. Even the treated corneas with advanced bullous keratopathy and stromal fibrosis had histological evidence of collagen fibers organization, but this effect seems to be decreased compared with corneas in initial stages of the disease.
- ItemSomente MetadadadosImpression Cytologic Analysis After Corneal Collagen Cross-Linking Using Riboflavin and Ultraviolet-A Light in the Treatment of Keratoconus(Lippincott Williams & Wilkins, 2010-10-01) Renesto, Adimara da Candelaria [UNIFESP]; Barros, Jeison de Nadai [UNIFESP]; Campos, Mauro [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Purpose: To report impression cytologic (IC) results after corneal cross-linking (CXL) using riboflavin and ultraviolet-A light in the treatment of keratoconus and compare the data with those from a group of subjects with the same disease.Methods: Forty eyes were distributed into 2 groups: patients in group 1 underwent CXL, whereas patients in group 2 received riboflavin 0.1% eyedrops for 1 month of topical use. IC specimens were obtained from all eyes before treatment and 1 and 3 months after treatment.Results: Patients in group 1 showed a decrease in goblet cell density on the superior conjunctiva after CXL (P = 0.008) but no difference on the temporal conjunctiva or in the cornea. Patients in group 2 demonstrated improvement in cell-to-cell contact of epithelial cells and reduced keratinization on the temporal conjunctiva after treatment (P = 0.003 and P = 0.034, respectively) but no changes on the superior conjunctiva or in the cornea. Fisher exact test comparison of IC total scores after treatment revealed no difference between groups.Conclusions: Despite changes in goblet cell density after corneal CXL in the superior conjunctiva and an improvement in the morphology of epithelial cells after the use of riboflavin eyedrops, comparison of total IC scores showed no difference between groups.
- ItemSomente MetadadadosA possible anti-proliferative and anti-metastatic effect of irradiated riboflavin in solid tumours(Elsevier B.V., 2007-12-08) Souza Queiroz, Karla Cristiana de; Zambuzzi, Willian Fernando; Souza, Ana Carolina Santos de; Silva, Rodrigo Augusto da; Machado, Daisy; Justo, Giselle Zenker; Carvalho, Hernandes F.; Peppelenbosch, Maikel P.; Ferreira, Carmen Verissima; Universidade Estadual de Campinas (UNICAMP); Universidade Federal de São Paulo (UNIFESP); Univ GroningenRiboflavin is a potent photosensitizer as well as part of the vitamin B complex. Recently we demonstrated that the products generated by irradiation of riboflavin have potential as anti-leukaemic therapy. the possible action, however, of the riboflavin photoproducts in solid cancers has not been addressed. Hence, we investigated the effects of irradiated riboflavin on androgen-independent human prostate cancer cells (PC3), a known model for solid tumour cells with an exceptional resistance to therapy. Our results show that riboflavin photoproducts are cytotoxic to these cells in a FasL-Fas-dependent manner. Furthermore, irradiated riboflavin inhibited matrix-degrading proteases, caused downregulation of VEGF and upregulation of TIMP1 suggesting anti-metastatic potential. Together, these results show that the anti-neoplastic action of riboflavin photoproducts is not limited to haematological malignancies, warranting clinical studies in solid tumours. (c) 2007 Elsevier Ireland Ltd. All rights reserved.