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1.
Ophthalmology ; 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38908553

RESUMO

PURPOSE: To validate the ability of theranostic imaging biomarkers in assessing corneal cross-linking (CXL) efficacy in flattening the maximum keratometry (Kmax) index. DESIGN: Prospective, randomized, multicenter, masked clinical trial (ClinicalTrails.gov identifier, NCT05457647). PARTICIPANTS: Fifty patients with progressive keratoconus. INTERVENTION: Participants were stratified to undergo epithelium-off (25 eyes) and epithelium-on (25 eyes) CXL protocols using an ultraviolet A (UV-A) medical device with theranostic software. The device controlled UV-A light both for performing CXL and assessing the corneal riboflavin concentration (riboflavin score) and treatment effect (theranostic score). A 0.22% riboflavin formulation was applied onto the cornea for 15 minutes and 20 minutes in epithelium-off and epithelium-on protocols, respectively. All eyes underwent 9 minutes of UV-A irradiance at 10 mW/cm2. MAIN OUTCOME MEASURES: The primary outcome measure was validation of the combined use of theranostic imaging biomarkers through measurement of their accuracy (proportion of correctly classified eyes) and precision (positive predictive value) to classify eyes correctly and predict a Kmax flattening at 1 year after CXL. Other outcome measures included change in Kmax, endothelial cell density, uncorrected and corrected distance visual acuity, manifest spherical equivalent refraction and central corneal thickness 1 year after CXL. RESULTS: Accuracy and precision of the theranostic imaging biomarkers in predicting eyes that had >0.1 diopter (D) of Kmax flattening at 1 year were 91% and 95%, respectively. The Kmax value significantly flattened by a median of -1.3 D (IQR, -2.11 to -0.49 D; P < 0.001); both the uncorrected and corrected distance visual acuity improved by a median of -0.1 logarithm of the minimum angle of resolution (logMAR; IQR, -0.3 to 0.0 logMAR [P < 0.001] and -0.2 to 0.0 logMAR [P < 0.001], respectively). No significant changes in endothelial cell density (P = 0.33) or central corneal thickness (P = 0.07) were noted 1 year after surgery. CONCLUSIONS: The study demonstrated the efficacy of integrating theranostics in a UV-A medical device for the precise and predictive treatment of keratoconus with epithelium-off and epithelium-on CXL protocols. Concentration of riboflavin and its UV-A light mediated photoactivation in the cornea are the primary factors determining CXL efficacy. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

2.
J Org Chem ; 89(4): 2320-2342, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38298114

RESUMO

In this study, we present a novel and environmentally sustainable protocol for the γ-hydrofunctionalization of N-allenyl compounds using various heteronucleophiles catalyzed solely by simple Brønsted acids. The method displays remarkable attributes, highlighting its sustainability, efficiency, regio- and stereoselectivity, as well as its versatile applicability to diverse heteroatom-containing enamides. Notably, our approach eliminates the need for metal catalysts and toxic solvents, representing a significant advancement in greener chemistry practices. We demonstrate the broad scope of our protocol by successfully scaling up reactions to gram-scale syntheses, underscoring its robustness for potential industrial implementation. The resulting γ-heterosubstituted enamides offer new possibilities for further synthetic transformations, yielding highly functionalized compounds with diverse applications. Mechanistic investigations reveal the pivotal role of CSA as a catalyst, enabling alcohol addition via a covalent activation mode.

3.
Graefes Arch Clin Exp Ophthalmol ; 262(8): 2569-2577, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38502352

RESUMO

PURPOSE: To assess the feasibility of theranostics to determine the riboflavin concentration in the cornea using clinically available ophthalmic formulations during epithelium-off (epi-off) and transepithelial (epi-on) corneal cross-linking procedures. METHODS: Thirty-two eye bank human donor corneas were equally randomized in eight groups; groups 1 to 3 and groups 4 to 8 underwent epi-off and epi-on delivery of riboflavin respectively. Riboflavin ophthalmic solutions were applied onto the cornea according to the manufacturers' instructions. The amount of riboflavin into the cornea was estimated, at preset time intervals during imbibition time, using theranostic UV-A device (C4V CHROMO4VIS, Regensight srl, Italy) and expressed as riboflavin score (d.u.). Measurements of corneal riboflavin concentration (expressed as µg/cm3) were also performed by spectroscopy absorbance technique (AvaLight-DH-S-BAL, Avantes) for external validation of theranostic measurements. RESULTS: At the end of imbibition time in epi-off delivery protocols, the average riboflavin score ranged from 0.77 ± 0.38 (the average corneal riboflavin concentration was 213 ± 190 µg/cm3) to 1.79 ± 0.07 (554 ± 103 µg/cm3). In epi-on delivery protocols, the average riboflavin score ranged from 0.17 ± 0.01 to 0.67 ± 0.19 (corneal riboflavin concentration ranged from 6 ± 5 µg/cm3 to 122 ± 39 µg/cm3) at the end of imbibition time. A statistically significant linear correlation (P ≤ 0.05) was found between the theranostic and spectrophotometry measurements in all groups. CONCLUSIONS: Real-time theranostic imaging provided an accurate strategy for assessing permeation of riboflavin into the human cornea during the imbibition phase of corneal cross-linking, regardless of delivery protocol. A large variability in corneal riboflavin concentration exists between clinically available ophthalmic formulations both in epi-off and epi-on delivery protocols.


Assuntos
Crosslinking Corneano , Fotoquimioterapia , Fármacos Fotossensibilizantes , Riboflavina , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Colágeno/metabolismo , Substância Própria/metabolismo , Epitélio Corneano/metabolismo , Bancos de Olhos , Estudos de Viabilidade , Ceratocone/tratamento farmacológico , Ceratocone/metabolismo , Ceratocone/diagnóstico , Soluções Oftálmicas/administração & dosagem , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/farmacocinética , Fármacos Fotossensibilizantes/administração & dosagem , Riboflavina/farmacocinética , Riboflavina/administração & dosagem , Doadores de Tecidos , Raios Ultravioleta
4.
Molecules ; 28(5)2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36903480

RESUMO

In 1971, chemists from Hoffmann-La Roche and Schering AG independently discovered a new asymmetric intramolecular aldol reaction catalyzed by the natural amino acid proline, a transformation now known as the Hajos-Parrish-Eder-Sauer-Wiechert reaction. These remarkable results remained forgotten until List and Barbas reported in 2000 that L-proline was also able to catalyze intermolecular aldol reactions with non-negligible enantioselectivities. In the same year, MacMillan reported on asymmetric Diels-Alder cycloadditions which were efficiently catalyzed by imidazolidinones deriving from natural amino acids. These two seminal reports marked the birth of modern asymmetric organocatalysis. A further important breakthrough in this field happened in 2005, when Jørgensen and Hayashi independently proposed the use of diarylprolinol silyl ethers for the asymmetric functionalization of aldehydes. During the last 20 years, asymmetric organocatalysis has emerged as a very powerful tool for the facile construction of complex molecular architectures. Along the way, a deeper knowledge of organocatalytic reaction mechanisms has been acquired, allowing for the fine-tuning of the structures of privileged catalysts or proposing completely new molecular entities that are able to efficiently catalyze these transformations. This review highlights the most recent advances in the asymmetric synthesis of organocatalysts deriving from or related to proline, starting from 2008.

5.
Int Ophthalmol ; 43(7): 2315-2328, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36587174

RESUMO

The Assessment of theranostic guided riboflavin/UV-A corneal cross-linking for treatment of keratoconus (ARGO; registration number NCT05457647) clinical trial tests the hypothesis that theranostic-guided riboflavin/UV-A corneal cross-linking (CXL) can provide predictable clinical efficacy for halting keratoconus progression, regardless of treatment protocol, i.e., either with or without epithelial removal. Theranostics is an emerging therapeutic paradigm of personalized and precision medicine that enables real-time monitoring of image-guided therapy. In this trial, the theranostic software module of a novel UV-A medical device will be validated in order to confirm its accuracy in estimating corneal cross-linking efficacy in real time. During CXL procedure, the theranostic UV-A medical device will provide the operator with an imaging biomarker, i.e., the theranostic score, which is calculated by non-invasive measurement of corneal riboflavin concentration and its UV-A light mediated photo-degradation. ARGO is a randomized multicenter clinical trial in patients aged between 18 and 40 years with progressive keratoconus aiming to validate the theranostic score by assessing the change of the maximum keratometry point value at 1-year postoperatively. A total of 50 participants will be stratified with allocation ratio 1:1 using a computer-generated stratification plan with blocks in two treatment protocols, such as epithelium-off or epithelium-on CXL. Following treatment, participants will be monitored for 12 months. Assessment of safety and performance of theranostic-guided corneal cross-linking treatment modality will be determined objectively by corneal tomography, corneal endothelial microscopy, visual acuity testing and slit-lamp eye examination.


Assuntos
Ceratocone , Fotoquimioterapia , Humanos , Adolescente , Adulto Jovem , Adulto , Ceratocone/diagnóstico , Ceratocone/tratamento farmacológico , Ceratocone/cirurgia , Medicina de Precisão , Crosslinking Corneano , Córnea/metabolismo , Raios Ultravioleta , Riboflavina/uso terapêutico , Fotoquimioterapia/métodos , Reagentes de Ligações Cruzadas/uso terapêutico , Fármacos Fotossensibilizantes/uso terapêutico , Topografia da Córnea , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Multicêntricos como Assunto
6.
Int Ophthalmol ; 42(1): 337-348, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34448966

RESUMO

BACKGROUND: Riboflavin/UV-A corneal cross-linking (CXL) for treating keratoconus and iatrogenic corneal ectasia has been well-established as first treatment option to stabilize corneal tissue biomechanical instability. Although the plethora of clinical studies has been published into the field, there is no systematic review assessing the type and frequency of adverse events after CXL. METHODS: A systemic literature review on clinical safety and adverse events after CXL in patients with keratoconus and corneal ectasia was performed using PubMed. A literature search was performed for relevant peer-reviewed publications. The main outcome measures extracted from the articles were adverse events, endothelial cell density, corrected distance visual acuity and maximum simulated keratometry. RESULTS: The most frequent adverse events after CXL were corneal haze and corneal edema, which were mild and transient. The severe adverse events were infrequent (cumulative incidence: < 1.3%) after CXL. The clinical benefits of CXL highly outweighed the risks for the treatment of keratoconus and corneal ectasia. CONCLUSIONS: The severe adverse events with permanent sequelae are infrequent after CXL and all are associated with corneal de-epithelialization, such as infectious keratitis and corneal scarring.


Assuntos
Ceratocone , Fotoquimioterapia , Colágeno/uso terapêutico , Topografia da Córnea , Reagentes de Ligações Cruzadas/uso terapêutico , Humanos , Ceratocone/tratamento farmacológico , Fármacos Fotossensibilizantes/efeitos adversos , Riboflavina/efeitos adversos , Raios Ultravioleta
7.
Graefes Arch Clin Exp Ophthalmol ; 258(4): 829-834, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31900647

RESUMO

PURPOSE: To assess corneal concentration of riboflavin in two different corneal crosslinking protocols performed by a novel image-guided therapeutic (or "theranostic") UV-A device. METHODS: Ten human eye bank donor tissues were used in this work. The tissues underwent corneal cross-linking according to the conventional treatment protocol (n = 5; 30 min of stromal soaking followed by 30 min of 3 mW/cm2 UV-A irradiance) and the iontophoresis-assisted transepithelial protocol (n = 5; soaking for 5 min at 1 mA/min and 9 min of 10 mW/cm2 UV-A irradiance) using a theranostic UV-A device (Vision Engineering Italy srl, Italy). The device provided real time assessment of riboflavin concentration by hyperspectral image analysis of the cornea. A 0.1% riboflavin hypotonic solution (Ricrolin+, Sooft Italia Spa, Italy) was used in all cases. RESULTS: Manual application of hypotonic riboflavin for 30 min into the stroma achieved greater corneal riboflavin concentration (425 ± 77 µg/cm3) than transepithelial delivery of riboflavin by corneal iontophoresis (195 ± 35 µg/cm3; P = 0.001). In both UV-A irradiation protocols, corneal riboflavin concentration decreased exponentially with a constant energy rate of 2.3 ± 0.5 J/cm2 and 1.8 ± 0.3 J/cm2 respectively. At the end of treatment, the average corneal concentration of riboflavin decreased by ≥ 85%, with values of 54 ± 29 µg/cm3 and 31 ± 9 µg/cm3 (P = 0.11), respectively. CONCLUSION: Manual application of riboflavin onto the stroma achieved almost 50% greater concentration of riboflavin than transepithelial delivery by corneal iontophoresis. The theranostic UV-A device provided a novel approach to estimate corneal concentration of riboflavin non-invasively during treatment.


Assuntos
Colágeno/uso terapêutico , Reagentes de Ligações Cruzadas/uso terapêutico , Ceratocone/tratamento farmacológico , Fotoquimioterapia/instrumentação , Riboflavina/uso terapêutico , Raios Ultravioleta , Acuidade Visual , Idoso , Desenho de Equipamento , Feminino , Humanos , Ceratocone/diagnóstico , Masculino , Fármacos Fotossensibilizantes/uso terapêutico , Doadores de Tecidos
8.
Int J Mol Sci ; 21(7)2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-32235449

RESUMO

In this study, we explore the behaviour of intracellular magnesium during bone phenotype modulation in a 3D cell model built to mimic osteogenesis. In addition, we measured the amount of magnesium in the mineral depositions generated during osteogenic induction. A two-fold increase of intracellular magnesium content was found, both at three and seven days from the induction of differentiation. By X-ray microscopy, we characterized the morphology and chemical composition of the mineral depositions secreted by 3D cultured differentiated cells finding a marked co-localization of Mg with P at seven days of differentiation. This is the first experimental evidence on the presence of Mg in the mineral depositions generated during biomineralization, suggesting that Mg incorporation occurs during the bone forming process. In conclusion, this study on the one hand attests to an evident involvement of Mg in the process of cell differentiation, and, on the other hand, indicates that its multifaceted role needs further investigation.


Assuntos
Magnésio/análise , Osteogênese , Fósforo/análise , Técnicas de Cultura de Células/métodos , Diferenciação Celular , Linhagem Celular Tumoral , Humanos , Magnésio/metabolismo , Fósforo/metabolismo
9.
Angew Chem Int Ed Engl ; 59(45): 20055-20064, 2020 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-32678935

RESUMO

The discovery of chemical methods enabling the construction of carbocycle-fused uracils which embody a three-dimensional and functional-group-rich architecture is a useful tool in medicinal chemistry oriented synthesis. In this work, an unprecedented amine-catalyzed [4+2] cross-cycloaddition is documented; it involves remotely enolizable 6-methyluracil-5-carbaldehydes and ß-aryl enals, and chemoselectively produces two novel bicyclic and tricyclic fused uracil chemotypes in good yields with a maximum level of enantiocontrol. In-depth mechanistic investigations and control experiments support an intriguing homo-synergistic organocatalytic approach, where the same amine organocatalyst concomitantly engages both aldehyde partners in a stepwise eliminative [4+2] cycloaddition, whose vinylogous iminium ion intermediate product may diverge-depending upon conditions-to either bicyclic targets by hydrolysis or tricyclic products by a second homo-synergistic trienamine-mediated stepwise [4+2] cycloaddition.

10.
Chemistry ; 25(67): 15272-15276, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31553479

RESUMO

The TBD (1,3,5-triazabicyclodec-5-ene) assisted three-component carbonylation of pyridine-2-methanamines is documented by means of CO2 as a benign CO surrogate. The redox-neutral methodology enables the realization of densely functionalized imidazo-pyridinones in high yields (up to 93 %) and excellent chemoselectivity. Combined computational and experimental investigations revealed an unprecedented RCOCl/TBD concerted electrophilic activation of carbon dioxide.

11.
Anal Bioanal Chem ; 410(2): 337-348, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29150807

RESUMO

The quantification of elemental concentration in cells is usually performed by analytical assays on large populations missing peculiar but important rare cells. The present article aims at comparing the elemental quantification in single cells and cell population in three different cell types using a new approach for single cells elemental analysis performed at sub-micrometer scale combining X-ray fluorescence microscopy and atomic force microscopy. The attention is focused on the light element Mg, exploiting the opportunity to compare the single cell quantification to the cell population analysis carried out by a highly Mg-selective fluorescent chemosensor. The results show that the single cell analysis reveals the same Mg differences found in large population of the different cell strains studied. However, in one of the cell strains, single cell analysis reveals two cells with an exceptionally high intracellular Mg content compared with the other cells of the same strain. The single cell analysis allows mapping Mg and other light elements in whole cells at sub-micrometer scale. A detailed intensity correlation analysis on the two cells with the highest Mg content reveals that Mg subcellular localization correlates with oxygen in a different fashion with respect the other sister cells of the same strain. Graphical abstract Single cells or large population analysis this is the question!


Assuntos
Corantes Fluorescentes/química , Magnésio/análise , Microscopia de Fluorescência/métodos , Imagem Óptica/métodos , Análise de Célula Única/métodos , Contagem de Células , Linhagem Celular Tumoral , Células Endoteliais da Veia Umbilical Humana , Humanos , Síncrotrons , Raios X
13.
Ophthalmology ; 124(6): 804-812, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28283279

RESUMO

PURPOSE: To compare clinical outcomes of transepithelial corneal cross-linking using iontophoresis (T-ionto CL) and standard corneal cross-linking (standard CL) for the treatment of progressive keratoconus 12 months after the operation. DESIGN: Prospective randomized controlled clinical trial. PARTICIPANTS: Thirty-four eyes of 25 participants with progressive keratoconus were randomized into T-ionto CL (22 eyes) or standard CL (12 eyes). METHODS: T-ionto CL was performed using an iontophoresis device with dextran-free 0.1% riboflavin-5-phosphate solution with enhancers and by irradiating the cornea with a 10 mW/cm2 ultraviolet A device for 9 minutes. Standard CL was performed according to the Dresden protocol. MAIN OUTCOME MEASURES: The primary outcome measure was stabilization of keratoconus after 12 months through analysis of maximum simulated keratometry readings (Kmax, diopters). Other outcome measures were corrected distance visual acuity (CDVA, logarithm of the minimum angle of resolution [logMAR]), manifest spherical equivalent refraction (D), central corneal thickness (CCT, micrometers) and endothelial cell density (ECD). Follow-up examinations were arranged at 3 and 7 days and 1, 3, 6, and 12 months. RESULTS: Twelve months after T-ionto CL and standard CL, Kmax on average flattened by -0.52±1.30 D (P = 0.06) and -0.82±1.20 D (P = 0.04), respectively. The mean change in CDVA was -0.10±0.12 logMAR (P = 0.003) and -0.03±0.06 logMAR (P = 0.10) after T-ionto CL and standard CL, respectively. The manifest spherical equivalent refraction changed on average by +0.71±1.44 D (P = 0.03) and +0.21±0.76 D (P = 0.38), respectively. The CCT and ECD measures did not change significantly in any group at 12 months. Significant differences in the outcome measures between treatments were found in the first week postoperatively. No complications occurred in the T-ionto CL group; 1 eye (8%) had sterile corneal infiltrates, which did not affect the final visual acuity, in the standard CL group. CONCLUSIONS: Significant visual and refractive improvements were found 12 months after T-ionto CL, though the average improvement in corneal topography readings was slightly lower than the Dresden protocol in the same period.


Assuntos
Substância Própria/metabolismo , Reagentes de Ligações Cruzadas , Iontoforese/métodos , Ceratocone/tratamento farmacológico , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Adulto , Contagem de Células , Colágeno/metabolismo , Topografia da Córnea , Endotélio Corneano/patologia , Feminino , Humanos , Ceratocone/metabolismo , Ceratocone/fisiopatologia , Masculino , Estudos Prospectivos , Refração Ocular/fisiologia , Riboflavina/uso terapêutico , Raios Ultravioleta , Acuidade Visual/fisiologia , Adulto Jovem
14.
Graefes Arch Clin Exp Ophthalmol ; 255(3): 575-582, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27858161

RESUMO

PURPOSE: To investigate the microstructure of endothelial keratoplasty grafts using two-photon optical microscopy. METHODS: Six endothelial keratoplasty grafts obtained from human donor corneoscleral tissues and prepared by submerged hydrodissection technique were imaged by two-photon optical microscopy. In each graft, two liquid bubbles were created in order to investigate the presence of a conserved cleavage plane regardless of the volume of posterior stroma that remained attached to Descemet's membrane (DM); the first bubble (bubble A) was generated under DM and the second bubble (bubble B) injection was done in order to obtain a layer of deep stroma that kept the two bubbles separated. Six human donor corneoscleral tissues were used as controls. Second harmonic generation and two-photon emitted fluorescence signals were collected from each specimen. RESULTS: Dissection of stroma occurred along the posterior collagen lamellae at variable distance from DM, which ranged between 3 and 16 µm in bubble A and between 23 and 41 µm in bubble B. The residual stroma included, anteriorly, bands of collagen lamellae, and thin bundles of stromal collagen fibrils, posteriorly, which were tightly intertwining with the underlying DM. There was no anatomically distinct plane of separation between these pre-Descemetic stromal collagen bundles and the overlying collagen lamellae with this hydrodissection technique. CONCLUSIONS: Two-photon optical microscopy provided label-free high-resolution imaging of endothelial keratoplasty grafts, showing that the most posterior stroma changes organization at approximately 10 µm above the DM. The pre-Descemetic stromal collagen fibrils form an intertwined complex with DM, which cannot be separated using hydrodissection.


Assuntos
Substância Própria/ultraestrutura , Ceratoplastia Endotelial com Remoção da Lâmina Limitante Posterior/métodos , Endotélio Corneano/ultraestrutura , Microscopia/métodos , Idoso , Humanos , Pessoa de Meia-Idade , Doadores de Tecidos , Tomografia de Coerência Óptica
15.
Int J Mol Sci ; 18(11)2017 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-29068419

RESUMO

Background: Diabetes mellitus (DM) is a multifactorial disease orphan of a cure. Regenerative medicine has been proposed as novel strategy for DM therapy. Human fibroblast growth factor (FGF)-2b controls ß-cell clusters via autocrine action, and human placental lactogen (hPL)-A increases functional ß-cells. We hypothesized whether FGF-2b/hPL-A treatment induces ß-cell differentiation from ductal/non-endocrine precursor(s) by modulating specific genes expression. Methods: Human pancreatic ductal-cells (PANC-1) and non-endocrine pancreatic cells were treated with FGF-2b plus hPL-A at 500 ng/mL. Cytofluorimetry and Immunofluorescence have been performed to detect expression of endocrine, ductal and acinar markers. Bromodeoxyuridine incorporation and annexin-V quantified cells proliferation and apoptosis. Insulin secretion was assessed by RIA kit, and electron microscopy analyzed islet-like clusters. Results: Increase in PANC-1 duct cells de-differentiation into islet-like aggregates was observed after FGF-2b/hPL-A treatment showing ultrastructure typical of islets-aggregates. These clusters, after stimulation with FGF-2b/hPL-A, had significant (p < 0.05) increase in insulin, C-peptide, pancreatic and duodenal homeobox 1 (PDX-1), Nkx2.2, Nkx6.1, somatostatin, glucagon, and glucose transporter 2 (Glut-2), compared with control cells. Markers of PANC-1 (Cytokeratin-19, MUC-1, CA19-9) were decreased (p < 0.05). These aggregates after treatment with FGF-2b/hPL-A significantly reduced levels of apoptosis. Conclusions: FGF-2b and hPL-A are promising candidates for regenerative therapy in DM by inducing de-differentiation of stem cells modulating pivotal endocrine genes.


Assuntos
Diferenciação Celular , Fator 2 de Crescimento de Fibroblastos/fisiologia , Células Secretoras de Insulina , Ductos Pancreáticos/fisiologia , Lactogênio Placentário/fisiologia , Diabetes Mellitus/terapia , Feminino , Fator 2 de Crescimento de Fibroblastos/metabolismo , Proteína Homeobox Nkx-2.2 , Proteínas de Homeodomínio , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas Nucleares , Ductos Pancreáticos/citologia , Ductos Pancreáticos/metabolismo , Lactogênio Placentário/metabolismo , Medicina Regenerativa/métodos , Fatores de Transcrição
16.
Chemistry ; 22(11): 3865-72, 2016 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-26743560

RESUMO

A new and flexible methodology catalyzed by bifunctional chiral thioureas has been developed to react ß-nitro oxindoles 1 with aldehydes. This approach allowed us to achieve the first enantioselective organocatalytic synthesis of 3-spiro-α-alkylidene-γ-butyrolactone oxindoles 3. We examined the scope of the two starting materials and, varying the structure of the ß-nitro oxindole 1, intriguing new products, derived from unexpected transformations, have been stereoselectively obtained. The aim of this study was to merge two potentially bioactive structural motifs: the spirooxindole substructure and the α-alkylidene-γ-butyrolactone moiety. A preliminary NMR study on the ability to reversibly trap 2-aminoethanethiol gave us promising results.

17.
Chemistry ; 22(50): 18156-18168, 2016 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-27798823

RESUMO

Great interest in new thermochemiluminescent (TCL) molecules, for example, in bioanalytical assays, has prompted the design and synthesis of a small library of more than 30 olefins to be subjected to photooxygenation, with the aim of obtaining new 1,2-dioxetane-based TCL labels with optimized properties. Fluorine atoms on the acridan system remarkably stabilize 1,2-dioxetanes when they are located in the 3- and/or 6-position (4 h and 4 i). On the other hand, 2,7-difluorinated acridan dioxetane (4 j) showed a significantly enhanced fluorescence quantum yield with respect to the unsubstituted dioxetane (4 a). Some of the synthesized olefins did not undergo singlet oxygen addition and a rationale was sought to ease the photooxygenation step, leading to the TCL dioxetanes. A chemometric approach has been adopted to exploit principal component analysis and linear discriminant analysis of the structural and electronic molecular descriptors obtained by DFT optimizations of olefins 3. This approach allows the steric and electronic parameters that govern dioxetane formation to be revealed.

18.
Vis Neurosci ; 33: E005, 2016 01.
Artigo em Inglês | MEDLINE | ID: mdl-27484961

RESUMO

The ability to noninvasively image the cone photoreceptor mosaic holds significant potential as a diagnostic for retinal disease. Central to the realization of this potential is the development of sensitive metrics for characterizing the organization of the mosaic. Here we evaluated previously-described and newly-developed (Fourier- and Radon-based) methods of measuring cone orientation in simulated and real images of the parafoveal cone mosaic. The proposed algorithms correlated well across both simulated and real mosaics, suggesting that each algorithm provides an accurate description of photoreceptor orientation. Despite high agreement between algorithms, each performed differently in response to image intensity variation and cone coordinate jitter. The integration property of the Fourier transform allowed the Fourier-based method to be resistant to cone coordinate jitter and perform the most robustly of all three algorithms. Conversely, when there is good image quality but unreliable cone identification, the Radon algorithm performed best. Finally, in cases where the cone coordinate reliability was excellent, the method previously described by Pum and colleagues performed best. These descriptors are complementary to conventional descriptive metrics of the cone mosaic, such as cell density and spacing, and have the potential to aid in the detection of photoreceptor pathology.


Assuntos
Algoritmos , Diagnóstico por Imagem/métodos , Técnicas de Diagnóstico Oftalmológico , Células Fotorreceptoras Retinianas Cones/citologia , Adulto , Anisotropia , Contagem de Células , Feminino , Análise de Fourier , Humanos , Masculino , Oftalmoscopia/métodos
19.
Retina ; 41(2): e20-e22, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-32769714

Assuntos
Retina , Humanos
20.
Retina ; 36(1): 171-80, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26110598

RESUMO

PURPOSE: To investigate the changes of the vitreomacular interface during a 1-year follow-up after idiopathic epiretinal membrane (iERM) surgery. METHODS: Six patients affected by fovea-attached iERM were recruited in this pilot study. Pars plana vitrectomy associated with epiretinal membrane peeling was performed uneventfully in all cases. In four cases, the inner limiting membrane was removed using Brilliant blue G. En face high-resolution adaptive optics and cross-sectional spectral domain optical coherence tomography retinal imaging were performed before and at 1, 3, 6, and 12 months after surgery. The microstructures of vitreomacular interface in high-resolution adaptive optics images were correlated to the cross-sectional spectral domain optical coherence tomography data. RESULTS: Preoperatively, adaptive optics images showed multiple abnormalities of the vitreomacular interface, such as macrofolds, microfolds, and hyperreflective microstructures. We identified two subtypes of iERM according to the distribution of microfolds over the foveal area, which included the radial-type and the grid-type iERM. After surgery, the morphology of the vitreomacular interface changed compared with the preoperative state. The number of both macrofolds and microfolds was reduced in all cases. The hyperreflective structures were still resolvable in all cases, however presenting different shape and morphology than preoperatively. In addition, they showed marked differences between eyes that had internal limiting membrane removal and eyes that did not. CONCLUSION: Adaptive optics imaging gives new insight into the changes of vitreomacular interface after iERM surgery. Enhanced multimodal imaging of the vitreomacular interface and retinal structures can be valuable to monitor treatment outcome of iERM.


Assuntos
Membrana Epirretiniana/diagnóstico , Membrana Epirretiniana/cirurgia , Imagem Multimodal , Vitrectomia , Idoso , Membrana Basal/cirurgia , Feminino , Humanos , Indicadores e Reagentes/administração & dosagem , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Período Pós-Operatório , Período Pré-Operatório , Retina/patologia , Corantes de Rosanilina/administração & dosagem , Tomografia de Coerência Óptica , Corpo Vítreo/patologia
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