Single-Molecule Catalysis in the Palladium Cross-Coupling Reaction Cycle.

Single-molecule (SM) methods are applied to study various types of catalytic processes in chemical and biochemical reactions. In this study, the Suzuki-Miyaura cross-coupling reaction forming a fluorescent product is investigated within the SM approximation. Stochastic analysis of emission intermittency in selected nanoscopic spots allows us to determine the single-molecule turnover frequency (SM-TOF) of the Pd catalyst in a specific probe reaction. We generate and analyze simulated intermittency time traces of a single catalyst surrounded by reactant molecules to assess the reliability of the method applied to real intermittency time trace data from hundreds of nanoscopic fluorescence spots. The results demonstrate that the proposed method can be used to evaluate the average SM-TOF of Pd in a cross-coupling reaction.

Acid selenites as new selenium precursor for CdSe quantum dot synthesis.

Chemical precursors for nanomaterials synthesis have become essential to tune particle size, composition, morphology, and unique properties. New inexpensive precursors investigation that precisely controls these characteristics is highly relevant. We studied new Se precursors, the acid selenites (R-O-SeOOH), to synthesize CdSe quantum dots (QDs). They were produced at room temperature by the Image 1 reaction with alcohols having different alkyl chains and were characterized by 1H NMR confirming their structures. This unprecedented precursor generates high-quality CdSe nanocrystals with narrow size distribution in the zinc-blend structure showing controlled optical properties. Advanced characterization detailed the CdSe structure showing stacking fault defects and its dependence on the used R-O-SeOOH. The QDs formation was examined using a time-dependent growth kinetics model. Differences in the nanoparticle surface structure influenced the optical properties, and they were correlated to the Se-precursor nature. Small alkyl chain acid selenites generally lead to more controlled QDs morphology, while the bigger alkyl chain leads to slightly upper quantum yields. Acid selenites can potentially replace Se-precursors at competitive costs in the metallic chalcogenide nanoparticles. Image 1 is chemically stable, and alcohols are cheap and less toxic than the reactants used today, making acid selenites a more sustainable Se precursor.

Fecal calprotectin levels in acute anterior uveitis in patients with spondyloarthritis / Níveis de calprotectina fecal na uveite anterior aguda em pacientes com espondiloartrites

ABSTRACT Purpose: This study measured fecal calprotectin levels in a series of patients with anterior uveitis in order to determine whether anterior uveitis patients with associated spondyloarthritis have higher levels of fecal calprotectin than patients with anterior uveitis of other etiologies. A third group of patients with spondyloarthritis without uveitis was also evaluated to understand the role of acute anterior uveitis in increasing fecal calprotectin. Methods: In this cross-sectional study, 28 patients were divided into three groups: (a) Group 1, spondyloarthritis and uveitis (n=9); (b) Group 2, spondyloarthritis without uveitis (n=10); and (c) Group 3, uveitis without spondyloarthritis (n=9). The levels of fecal calprotectin were determined. Results: Groups 1 and 2 showed higher median fecal calprotectin levels (101.0 and 93.0 µg/g, respectively) compared with Group 3 (9.0 µg/g) (p=0.02). However, no relationship between fecal calprotectin levels and the presence of uveitis with spondyloarthritis could be demonstrated. Conclusion: Patients with spondyloarthritis with or without acute anterior uveitis have significantly elevated levels of fecal calprotectin. This test may be useful for differentiating spondyloarthrit-associated uveitis from uveitis of other etiologies.

RESUMO Objetivo: Este estudo avaliou os níveis de calprotectina fecal em uma série de pacientes com uveíte anterior na tentativa de determinar se pacientes com uveíte associada com espondiloartrites apresentam níveis mais elevados desta proteína do que pacientes com uveíte anterior de outras etiologias. Um terceiro grupo com espondiloartrites sem uveíte também foi incluído na avaliação para entendimento do papel da uveíte anterior no aumento da calprotectina fecal. Métodos: Estudo transversal de 28 pacientes divididos em três grupos: (a) com espondiloartrites e uveíte (n=9); (b) com espondiloartrites sem uveíte (n=10) e (c) com uveíte sem espondiloartrites (n=9). A dosagem de calprotectina fecal foi avaliada. Resultados: Pacientes com uveíte anterior associada a espondiloartrites apresentaram valores medianos maiores de calprotectina fecal (101 µg/g) que os valores dos pacientes com uveíte sem espondiloartrites (9 µg/g), pacientes com espondiloartrites sem uveíte que também demonstraram valores maiores (93.0 µg/g) que os dos pacientes com uveíte sem espondiloartrites (p=0,02). Conclusão: Pacientes com espondiloartrites com e sem uveíte anterior aguda demonstraram níveis significativamente elevados de calprotectina fecal. Este teste pode ser útil na diferenciação entre uveítes associadas com espondiloartrites de uveítes de outras etiologias. Entretanto, não foi possível demonstrar associação entre o aumento dos níveis de calprotectina fecal e a presença da uveíte em espondiloartrites.

Fecal calprotectin levels in acute anterior uveitis in patients with spondyloarthritis.

PURPOSE: This study measured fecal calprotectin levels in a series of patients with anterior uveitis in order to determine whether anterior uveitis patients with associated spondyloarthritis have higher levels of fecal calprotectin than patients with anterior uveitis of other etiologies. A third group of patients with spondyloarthritis without uveitis was also evaluated to understand the role of acute anterior uveitis in increasing fecal calprotectin. METHODS: In this cross-sectional study, 28 patients were divided into three groups: (a) Group 1, spondyloarthritis and uveitis (n=9); (b) Group 2, spondyloarthritis without uveitis (n=10); and (c) Group 3, uveitis without spondyloarthritis (n=9). The levels of fecal calprotectin were determined. RESULTS: Groups 1 and 2 showed higher median fecal calprotectin levels (101.0 and 93.0 µg/g, respectively) compared with Group 3 (9.0 µg/g) (p=0.02). However, no relationship between fecal calprotectin levels and the presence of uveitis with spondyloarthritis could be demonstrated. CONCLUSION: Patients with spondyloarthritis with or without acute anterior uveitis have significantly elevated levels of fecal calprotectin. This test may be useful for differentiating spondyloarthrit-associated uveitis from uveitis of other etiologies.

Subconjunctival adalimumab for treatment of dry eye disease in Sjögren's syndrome / Tratamento de olho seco com adalimumabe subconjuntival em pacientes portadores da síndrome de Sjögren

ABSTRACT Objective To describe the use of subconjuctival administration of the anti-tumor necrosis factor agent adalimumab for treatment of dry eye in patients with Sjögren's syndrome, and to investigate conjunctival healing. Methods Prospective, nonrandomized, noncomparative interventional case series including consecutive patients with Sjögren's syndrome and dry eye disease treated with subconjunctival adalimumab, who were refractory to conventional treatment. Patients with infectious ocular surface involvement or structural changes in the tear pathway or eyelids were excluded. Data recorded included age, sex, lissamine green staining pattern, Schirmer test results, intraocular pressure, conjunctival mobility, tear break up time and findings of biomicroscopic evaluation, following fluorescein dye instillation. The Ocular Surface Disease Index questionnaire validated for the Portuguese language was used for subjective assessment of patients. Results Eleven eyes of eight patients were studied. Mean patient age was 53±13.4 years. Patients were treated with subconjunctival injection of 0.03 mL of adalimumab and followed for 90 days thereafter. There were no statistically significant objective improvement (objective tests results; p>0.05) and no statistically significant changes in intraocular pressure (p=0.11). Questionnaire responses revealed a significant improvement in ocular symptoms (p=0.002). Conclusion Based on the Ocular Surface Disease Index questionnaire, subconjunctival administration of adalimumab improved dry eye symptoms. However, objective assessments failed to reveal statistically significant improvements.

RESUMO Objetivo Descrever o uso subconjuntival do antifator de necrose tumoral adalimumabe para o tratamento do olho seco em pacientes com síndrome de Sjögren e avaliar a cicatrização conjuntival. Métodos Série de casos intervencionista com desenho prospectivo, não randomizado, não comparativo. O medicamento adalimumabe foi aplicado em região subconjuntival em pacientes com síndrome de Sjögren e olho seco que eram resistentes a outras terapias convencionais. Pacientes com patologias oculares de origem infecciosa ou com alterações estruturais nas vias lacrimais e pálpebras foram excluídos do estudo. Os dados coletados incluíram idade, sexo, teste com lisamina verde, teste de Schirmer, pressão intraocular, mobilidade conjuntival, teste de ruptura do filme lacrimal, e avaliação biomicroscópica com colírio de fluoresceína. Além disso, o questionário Ocular Surface Disease Index validado para a língua portuguesa foi aplicado com objetivo de avaliar subjetivamente a resposta dos pacientes ao tratamento. Resultados Onze olhos de oito pacientes foram estudados. A idade média dos pacientes foi de 53±13,4 anos. A dose aplicada de adalimumabe subconjuntival foi de 0,03mL, e a duração do seguimento foi de 90 dias após a injeção. Não houve melhora estatisticamente significativa nos testes objetivos (todos apresentaram p>0,05). A pressão intraocular também não sofreu variações estatisticamente significativas (p=0,11). Entretanto, por meio do questionário, foi registrada melhora significativa dos sintomas oculares (p=0,002). Conclusão O uso do adalimumabe subconjuntival melhorou os sintomas de olho seco, avaliados por meio do questionário Ocular Surface Disease Index, mas não houve melhora estatisticamente significativa na avaliação objetiva.

Reactive Phenanthrene Derivatives as Markers of Amino Groups in Fluorescence Microscopy of Surface Modified Micro-Zeolite L.

Two reactive phenanthrene derivatives, 4-(1H phenanthrol [9,10-d] imidazole-2-yl) benzaldehyde (PIB) and 6,9-dimethoxyphenanthro[9,10-c]furan-1,3-dione (PA) with high fluorescent quantum yields were prepared and used as fluorescent marker in fluorescence microscopy. In particular, silane modified µmZeolite-L containing amino group (-NH2) in the surface were labeled with the phenanthrene derivatives allowing good imaging resolution and spectroscopy measurements. The presence of a large Stokes shift of the probes due to their intramolecular charge-transfer character gives an advantage of the compounds in confocal laser fluorescence microscopy due to easy signal separation in excitation and emission wavelengths. On the other hand, these results open up the possibility of using these probes for visualization of Zeolite-based materials commonly used as catalysts in thermal and photochemical reactions.

Dry eye and percentage of body fat: a cross-sectional prospective study.

BACKGROUND: Dry eyes are common in the general population. Some studies associate high prevalence of dry eyes with lipid metabolic changes and body fat composition. AIM: To study the association of dry eye with percentage of body fat. METHODS: One hundred and thirty five individuals (44 males and 91 females; median age of 42 years) were studied in a cross-sectional prospective study. Schirmer test and TBUT (tear breakup time) test were used to access dry eye. Body composition (percentage of lean and fat mass) were calculated using anthropometric measurements that included height, weight, abdominal, waist and neck circumference. RESULTS: About 44.4% of the sample had abnormal Schirmer test, and 70.3% had abnormal TBUT. Schirmer tests values were associated with age (p = 0.0006) female gender (p = 0.04) and percentage of body fat (p = 0.02). Abnormal TBUT test associated only with age (p = 0.0005). CONCLUSIONS: Percentage of body fat is associated with abnormal Schirmer but not TBUT test.

Dry eyes in patients with diabetes mellitus.

Dry eyes may be caused by impairment in the tear production or excessive tear evaporation and are associated with photophobia, red eyes, vision impairment, local pain and pruritus. It has been described that patients with Diabetes Mellitus (DM) may have a higher prevalence of dry eyes than normal population. This is a case control study of 120 patients with Diabetes Mellitus (DM) and 120 paired controls aiming to compare their prevalence of dry eyes (by the Schirmer test) and its severity (measured by OSDI or Ocular Surface Disease Index) as well as their association with diseases' clinical variables. We found that 38.3% of DM patients had dry eyes, a prevalence that was higher than controls (p = 0.02). At univariate analysis, they were found to be more common in older individuals (p = 0.001) with type 2 diabetes (p = 0.001) and in those using metformin (p = 0.001). A multivariate linear regression showed that metformin use was the only independent variable associated with dry eyes. When patients with dry eyes with and without DM were compared, no differences in the symptom's intensity were found.

Single-Molecule Observations Provide Mechanistic Insights into Bimolecular Knoevenagel Amino Catalysis.

While single-molecule (SM) methods have provided new insights to various catalytic processes, bimolecular reactions have been particularly challenging to study. Here, the fluorogenic Knoevenagel condensation of an aromatic aldehyde with methyl cyanoacetate promoted by surface-immobilized piperazine is quantitatively characterized using super-resolution fluorescence imaging and stochastic analysis using hidden Markov modeling (HMM). Notably, the SM results suggest that the reaction follows the iminium intermediate pathway before the formation of a fluorescent product with intramolecular charge-transfer character. Moreover, the overall process is limited by the turnover rate of the catalyst, which is involved in multiple steps along the reaction coordinate.

Highly fluorescent hybrid pigments from anthocyanin- and red wine pyranoanthocyanin-analogs adsorbed on sepiolite clay.

Flavylium cations serve as models for the chemical and photochemical reactivity of anthocyanins, the natural plant pigment responsible for many of the red, blue and purple colors of fruits and flowers. Likewise, pyranoflavylium cations serve as models of the fundamental chromophoric moiety of pyranoanthocyanins, molecules that can form from reactions of grape anthocyanins in red wines during their maturation. In the present work, hybrid pigments are prepared by the adsorption of a series of five synthetic flavylium cations (FL) and five synthetic pyranoflavylium cations (PFL) on sepiolite clay (SEP). The FL are smaller in size than the PFL, but both can in principle fit into the tunnels and/or external grooves (with dimensions of 3.7 × 10.6 Å) of SEP. Measurements of the fluorescence quantum yields of the adsorbed dyes indicate that they are at least as fluorescent as in acidic acetonitrile solution, and in a few cases substantially more fluorescent. The observation of biexponential fluorescence decays is consistent with emission from dye molecules adsorbed at two distinct sites, presumably tunnels and grooves. These hybrid materials also have improved properties in terms of stability of the color in contact with pH 10 aqueous solution and resistance to thermal degradation of the dye. SEP thus appears to be a promising substrate for the development of highly fluorescent flavylium or pyranoflavylium cation-derived hybrid pigments with improved color and thermal stability.

Monitoring the Activity of Immobilized Lipase with Quinizarin Diester Fluoro-Chromogenic Probe.

Quinizarin diester is used as a fluoro-chromogenic substrate of the activity of lipase supported in poly(methylmetacrylate) beads (CALB, Novozym® 435) dispersed in organic solvents. The monoester and diester of quinizarin are both non-fluorescent species contrasting with the enzymatic product quinizarin that shows optical absorption in the visible region and strong fluorescence signal. The enzymatic conversion is accomplished by spectroscopic measurements and it follows a sigmoid curve from which the mean reaction time of the enzymatic process can be determined. This parameter indicates the enzyme activity of the immobilized lipase. Its dependency with the amount of lipase allowed the determination of the ratio of the catalytic rate and the Michaelis constant (kc/Km) and the experimental value found was (1.0 ± 0.1) × 10-2 mg-1/min in the case of quinizarin diacetate.

Orbital myosits in a patient with Behçet's disease / Miosite orbitária em paciente com doença de Behçet

Abstract The etiological diagnosis of orbital myositis (OM) is a challenge. Although it has been associated with previous infectious disease, diseases with autoimmune background, thyroidopathies or with paraneoplasic syndrome, most of them still remain as idiopathic. We describe here a case of OM uncovering a Behçet disease that is considered a rare cause for this kind of eye involvement.

Resumo Trata-se de um caso de ceratite bilateral e simultânea por Acremonium relacionada ao uso intermitente e sem respeitar a lateralidade O diagnóstico etiológico da miosite orbitária (MO) é desafiador. Embora ela tenha sido relacionada com doenças infecciosas prévias, doenças associadas à autoimunidade, tireoidopatias ou síndromes para neoplásicas, a maioria delas ainda permanece como idiopática. Descreve-se aqui, um caso de MO revelando o diagnóstico de doença de Behçet, doença considerada como uma causa pouco comum para este tipo de envolvimento ocular.

Styryl dye formation promoted by catalytic centers of piperazine bound to a silica surface traced by single molecule fluorescence microscopy.

The styryl dye (E)-2-[3-[4-(diphenylamine) phenyl]-1-(p-tolyl)-allylidene]-malononitrile (DFTAM) was prepared by Knoevenagel condensation using homogeneous and surface bound amino catalysts. The catalysis by surface bound piperazine allowed the study of the condensation reaction at a single molecule (SM) level using total internal fluorescence microscopy (TIRFM). The turnover rate of the surface catalyst is dependent on the presence of the byproduct water of the condensation reaction. The addition of zeolite particles as water traps improves the catalytic activity indicated by the highest number of emissive centers mapped with super resolved fluorescence imaging and longest intensity-time trajectories showing SM bursting events. This particular condensation reaction highlights the applicability of the method to study multi-step organic reactions in the condensed phase in which the product is a fluorescent species.

Aryl-Substituted Ruthenium(II) Complexes: A Strategy for Enhanced Photocleavage and Efficient DNA Binding.

Ruthenium polypyridine complexes have shown promise as agents for photodynamic therapy (PDT) and tools for molecular biology (chromophore-assisted light inactivation). To accomplish these tasks, it is important to have at least target selectivity and great reactive oxygen species (ROS) photogeneration: two properties that are not easily found in the same molecule. To prepare such new agents, we synthesized two new ruthenium complexes that combine an efficient DNA binding moiety (dppz ligand) together with naphthyl-modified (1) and anthracenyl-modified (2) bipyridine as a strong ROS generator bound to a ruthenium complex. The compounds were fully characterized and their photophysical and photochemical properties investigated. Compound 2 showed one of the highest quantum yields for singlet oxygen production ever reported (ΦΔ= 0.96), along with very high DNA binding (log Kb = 6.78). Such photochemical behavior could be ascribed to the lower triplet state involving the anthracenyl-modified bipyridine, which is associated with easier oxygen quenching. In addition, the compounds exhibited moderate selectivity toward G-quadruplex DNA and binding to the minor groove of DNA, most likely driven by the pendant ligands. Interestingly, they also showed DNA photocleavage activity even upon exposure to a yellow light-emitting diode (LED). Regarding their biological activity, the compounds exhibited an exciting antibacterial action, particularly against Gram-positive bacteria, which was enhanced upon blue LED irradiation. Altogether, these results showed that our strategy succeeded in producing light-triggered DNA binding agents with pharmacological and biotechnological potential.

Methyltransferase-directed covalent coupling of fluorophores to DNA.

We report an assay for determining the number of fluorophores conjugated to single plasmid DNA molecules and apply this to compare the efficiency of fluorophore coupling strategies for covalent DNA labelling. We compare a copper-catalyzed azide-alkyne cycloaddition reaction, amine to N-hydroxysuccinimidyl ester coupling reaction and strain-promoted azide-alkyne cycloaddition reaction for fluorescent DNA labelling. We found increased labelling efficiency going from the amine to N-hydroxysuccinimidyl ester coupling reaction to the copper-catalyzed azide-alkyne cycloaddition and found the highest degree of DNA labelling with the strain-promoted azide-alkyne cycloaddition reaction. We also examined the effect of labelling on the DNA structure using atomic force microscopy. We observe no distortions or damage to the DNA that was labeled using the amine to N-hydroxysuccinimidyl ester and strain-promoted azide-alkyne cycloaddition coupling reactions. This was in contrast to the copper-catalyzed azide-alkyne cycloaddition reaction, which, despite the use of copper-coordinating ligands in the labelling mixture, leads to some structural DNA damage (single-stranded DNA breaks).

Imaging the photoinduced charge injection in CdS/TiO2 nanoparticles by the sequential fluorescence mapping method.

The combination of a sensitizer and TiO2 nanoparticles forming a photocatalytic material is a central issue in many fields of applied photochemistry. The charge injection of emissive sensitizers into the conduction band of the semiconductor TiO2 may form a photoactive region that becomes dark, or it has a very low emission signal due to the generation of sensitizer radicals. However, by sequential coupling of a selected photoredox dye, such as resazurin, the dark region may become fluorescent at the interfaces where the charge injection has taken place due to the concomitant formation of fluorescent resorufin by cascade electron transfer. Using this strategy and a total internal reflection fluorescence microscopy (TIRFM) image, the charge injection in TiO2/CdS and SiO2/TiO2/CdS nanoparticles is investigated The method allows the charge injection efficiency of the excited CdS into TiO2 to be evaluated qualitatively, explaining the differences observed for these photocatalytic materials in H2 generation.

The spatial distribution of the photostability of thionine in zeolite L nanochannels investigated by Photobleaching Lifetime Imaging Microscopy.

Dye photobleaching is a photochemical reaction that can be investigated locally using fluorescence microscopy techniques. In this study, a user-friendly computational tool to assist photobleaching experiments called Photobleaching Lifetime Imaging Microscopy (PbLIM) is presented. With this tool it is possible to recover the photobleaching kinetics spatially, where a photobleaching lifetime is generated for each pixel of the image. Our model was applied to the photobleaching process of thionine encapsulated into the one-dimensional nano-channels of Zeolite L (ZL), from where we gained insight into the molecular oxygen distribution inside the ZL channels, as well as the detailed photobleaching of the confined thionine.

Olho seco nas espondiloartrites: prevalência e associação com perfil clínico / Eye dry in spondyloarthritis: prevalence and association with clinical profile

Objetivo: Determinar a prevalência de olho seco em pacientes com espondiloartrite. Métodos: O estudo foi realizado entre abril de 2012 à maio de 2013 em um hospital terciário brasileiro. O grupo teste apresentavam 49 pacientes com espondiloartrite (espondilite anquilosante, espondiloartropatia indiferenciada, artrite psoriásica, artrite relacionada a doença inflamatória intestinal) baseados em critérios aprovados. Todos os pacientes foram perguntados sintomas de secura ocular através de um questionário e testes de diagnósticos de olho seco (Schirmer I e BUT) foram examinados. Pacientes com espondiloartrite foram investigados o HLA-B27 e o BASDAI. Resultados: A idade média dos pacientes foi de 48,02 ± 11,66 anos. A maioria dos pacientes eram homens (71,42%). O olho seco parecia mais comum em HLA B27 presente, mas a diferença não foi estatisticamente significativa. Conclusão: Neste estudo, olho seco parecia mais comum em pacientes com espondiloartropatia do que no grupo controle

Objective: To determine the prevalence of dry eye in patients with SpA. Methods: We conduced a study between April 2012 and May 2013 in a Brazilian tertiary hospital. The test group included forty-nine patients with SpA (akylosing spondylitis, undifferentied spondyloarthropathy, psoriatic arthritis, or enteropathic arthropathy) based on accepted criteria. A control group of 49 individuals was matched of age and gender. All the patients were asked about sicca symptoms by using sicca questionnaire and dry eye diagnostic tests (Schirmer I and tear break up time) were examined. Patients with SpA investigated HLA-B27 and BASDAI. Results: The mean age of the patients was 48,02±11,66 years. Most of the patients were men (71,42%). Dry eye seemed more common in HLA B27 present, but the difference was not statistically significant. Conclusion: In this study, dry eye seemed more common in patients with spondyloarthropathy than in control group

Lúpus eritematoso sistêmico e vasculite retiniana / Lupus erythematosus and vasculitis retinal

Descreve-se o caso clinico de uma paciente em tratamento psiquiátrico cujas manifestações oculares levaram ao diagnóstico de lúpus eritematoso sistêmico

A clinical case of a patient in psychiatric treatment whose ocular manifestations led to the diagnosis of systemic lupus erythematosus is described

Necrose retininana aguda em paciente com lúpus eritematoso sistêmico / Necrosis retininana acute in patient with systemic lupus erythematosus

O Lúpus Eritematoso Sistêmico (LES) é uma doença proteiforme que pode ter manifestações oculares como vasculites retinianas, uveites e neuropatias óticas. Todavia pela imunodepressão causada tanto pela própria doença como pelo seu tratamento, esses pacientes estão sujeitos a várias formas de infecção que também podem causar manifestações oftalmológicas exigindo um diagnóstico diferencial cuidadoso. Descrevemos aqui o caso de um paciente com overlap entre LES e esclerodermia que desenvolveu vasculite retinina e necrose de retina secundária a infecção por herpes

Systemic lupus erythematosus (SLE) is a disease that can have variable eye manifestations such as ocular retinal vasculitis, uveitis and optic neuropathies. However because of the immunosuppression caused either by the disease itself or its treatment, these patients are subject to various forms of infection that can also cause ophthalmologic manifestations, requiring a careful differential diagnosis. Here we describe the case of a patient with overlap between SLE and scleroderma and retinal vasculitis that developed retinal necrosis secondary herpes infection