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1.
Anal Bioanal Chem ; 415(15): 2891-2905, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36849616

RESUMO

Polyurethanes (PUR) are a group of polymers synthesized from different diisocyanate and polyol monomers resulting in a countless number of possible structures. However, the large market demand, and the variety of application fields justify the inclusion of PUR in microplastic (MP) investigation. This study aimed at providing comprehensive information on PUR within MP analysis by pyrolysis-gas chromatography-mass spectrometry to clarify whether (i) it is possible to make a reliable statement on the PUR content of environmental samples based on a few pyrolysis products and (ii) which restrictions are required in this context. PUR were managed as subclasses defined by the diisocyanates employed for polymer synthesis. Methylene diphenyl diisocyanate (MDI)- and toluene diisocyanate (TDI)-based PUR were selected as subclasses of greatest relevance. Different PUR were pyrolyzed directly and under thermochemolytic conditions with tetramethylammonium hydroxide (TMAH). Distinct pyrolytic indicators were identified. The study supported that the use of TMAH greatly reduced the interactions of pyrolytic MP analytes with the remaining organic matrix of environmental samples and the associated negative effects on analytical results. Improvements of chromatographic behavior of PUR was evidenced. Regressions (1-20 µg) showed good correlations and parallelism tests underlined that quantitation behavior of different MDI-PUR could be represented by the calibration of just one representative with sufficient accuracy, entailing a good estimation of the entire subclass if thermochemolysis were used. The method was exemplary applied to road dusts and spider webs sampled around a plastic processing plant to evaluate the environmental spread of PUR in an urban context. The environmental occurrence of MDI-PUR as MP was highly influenced by the proximity to a potential source, while TDI markers were not observed.

2.
Int J Mol Sci ; 24(19)2023 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-37833862

RESUMO

The search for alternative ways to give a second life to materials paved the way for detailed investigation into three silica-polyethylenimine (Si-PEI) materials for the purpose of CO2 adsorption in carbon capture and storage. A solvent extraction procedure was investigated to recover degraded PEIs and silica, and concomitantly, pyrolysis was evaluated to obtain valuable chemicals such as alkylated pyrazines. An array of thermal (TGA, Py-GC-MS), mechanical (rheology), and spectroscopical (ATR-FTIR, 1H-13C-NMR) methods were applied to PEIs extracted with methanol to determine the relevant physico-chemical features of these polymers when subjected to degradation after use in CO2 capture. Proxies of degradation associated with the plausible formation of urea/carbamate moieties were revealed by Py-GC-MS, NMR, and ATR-FTIR. The yield of alkylpyrazines estimated by Py-GC-MS highlighted the potential of exhausted PEIs as possibly valuable materials in other applications.


Assuntos
Polietilenoimina , Dióxido de Silício , Dióxido de Silício/química , Polietilenoimina/química , Dióxido de Carbono/química , Espectroscopia de Ressonância Magnética , Adsorção
3.
Environ Sci Technol ; 51(11): 6580-6589, 2017 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-28437609

RESUMO

Water-soluble organic compounds (WSOCs) were extracted from corn stalk biochar produced at increasing pyrolysis temperatures (350-650 °C) and from the corresponding vapors, collected as bio-oil. WSOCs were characterized by gas chromatography (semivolatile fraction), negative electron spray ionization high resolution mass spectrometry (hydrophilic fraction) and fluorescence spectroscopy. The pattern of semivolatile WSOCs in bio-oil was dominated by aromatic products from lignocellulose, while in biochar was featured by saturated carboxylic acids from hemi/cellulose and lipids with concentrations decreasing with decreasing H/C ratios. Hydrophilic species in poorly carbonized biochar resembled those in bio-oil, but the increasing charring intensity caused a marked reduction in the molecular complexity and degree of aromaticity. Differences in the fluorescence spectra were attributed to the predominance of fulvic acid-like structures in biochar and lignin-like moieties in bio-oil. The divergence between pyrolysis vapors and biochar in the distribution of WSOCs with increasing carbonization was explained by the hydrophobic carbonaceous matrix acting like a filter favoring the release into water of carboxylic and fulvic acid-like components. The formation of these structures was confirmed in biochar produced by pilot plant pyrolysis units. Biochar affected differently shoot and root length of cress seedlings in germination tests highlighting its complex role on plant growth.


Assuntos
Carvão Vegetal , Água , Cromatografia Gasosa-Espectrometria de Massas , Compostos Orgânicos
4.
Chemphyschem ; 17(23): 3948-3953, 2016 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-27643799

RESUMO

LAC (hydroxylactone (1R,5S)-1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one) is one of the most interesting products of the pyrolysis of cellulose and represents a useful chiral building block in organic synthesis. A computational investigation at the DFT level on the mechanism of formation of LAC shows that this species can be obtained following two reaction paths, path A and path B, starting from a well-known pyrolysis product (ascopyrone P). A series of internal rearrangements involving in all cases a proton transfer leads directly to LAC (path B). An alternative path (path A) can be also followed. From this path, via a "gate" connecting the two reaction channels, it is possible to reach path B and form LAC. In both cases, the rate-determining step of the process is the initial keto-enol isomerization. We found that water, which is present in the reaction mixture, "catalyzes" the reaction by assisting the proton transfers present in all the steps of the process. In particular, water lowers the barrier of the rate-determining step that becomes 40.9 kcal mol-1 (79.4 kcal mol-1 in the absence of water). The corresponding computed rate constant is 4.3×10 s-1 at 500 °C, a value which is consistent with the presence of LAC in the absence of metal catalysts. The results of this study on the non-catalyzed process underpin the important role played by water in the formation of pyrolysis products of cellulose where proton transfer is a key mechanistic step.

5.
Int Orthop ; 40(4): 737-43, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26508497

RESUMO

PURPOSE: During growth, hallux valgus could present associated with flatfoot. Considering the current disagreement about correction of hallux valgus during growth and the lack of reports about simultaneous correction of hallux valgus associated with flexible flatfoot, we present simultaneous treatment of both deformities during growth combining subtalar arthroeresis and SERI first metatarsal osteotomy, reporting results at an average five-year follow-up. METHODS: Thirty-two children (64 feet, age range 8-12 years) affected by hallux valgus associated with flexible flatfoot underwent surgical treatment combining SERI first metatarsal osteotomy and subtalar arthroereisis with bioabsorbable endorthotic implant. Clinical evaluation was summarized with AOFAS score, and standard standing radiographs were performed. RESULTS: AOFAS score ranged from 86 ± 2 to 98 ± 2 (hindfoot) and from 80 ± 4 to 98 ± 2 (forefoot). HVA ranged from 21° ± 2 to 5° ± 2, IMA from 14° ± 2 to 7° ± 2, DMAA from 18° ± 2 to 2° ± 2, and Meary's angle from 162° ± 11 to 175° ± 4. Complications included one case of delayed wound healing, inflammatory skin reaction around the outlet of the percutaneous Kirschner wire in two cases, displacement of the endorthotic implant in one case, and a second surgery to replace the implant. CONCLUSIONS: SERI osteotomy and subtalar arthroereisis resulted in an effective, technically simple and easily combined approach, with a high rate of good results and low rate of complications at mid-term follow-up. These techniques performed simultaneously represent a viable option in case of hallux valgus associated with flexible flatfoot during growth. Nevertheless, considering the limitations of this study, we believe that a larger case series and a longer follow-up should be desirable.


Assuntos
Pé Chato/cirurgia , Hallux Valgus/cirurgia , Ossos do Metatarso/cirurgia , Osteotomia/métodos , Implantes Absorvíveis/efeitos adversos , Criança , Feminino , Pé Chato/complicações , Seguimentos , Pé/cirurgia , Hallux Valgus/complicações , Humanos , Masculino , Osteotomia/efeitos adversos , Resultado do Tratamento
6.
Int Orthop ; 40(8): 1615-1623, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26459107

RESUMO

PURPOSE: A minimally invasive anterior approach appears to be an attractive alternative to achieve capital realignment without violating femoral head vascular supply and avoiding hip dislocation in slipped capital femoral epiphysis. The aim of this study was to detail the technical steps of subcapital realignment through a minimally invasive anterior approach and to report the preliminary results of this procedure in a prospective cohort of patients with stable slips. METHODS: Nine patients underwent subcapital cuneiform wedge resection through a minimally invasive anterior approach without hip dislocation for moderate or severe stable slips between April 2012 and April 2013. Prophylactic stabilization of the contralateral hip was performed in all cases. A minimum 18 months follow-up was available. Clinical course was assessed using the Harris hip score and the hip range of motion. The degree of slippage as proposed by Southwick, the lateral α angle and the epiphyseal-metaphyseal distance allowed radiographic assessment. RESULTS: No patients were lost during follow-up, which was on average 28 months. No intraoperative complications occurred; one postoperative transient apraxia of the femoral cutaneous nerve, which completely recovered in six months, was recorded. Southwick angle, lateral α angle and epiphyseal-metaphyseal distance all improved substantially postoperatively. No cases of avascular necrosis were detected. CONCLUSION: Subcapital cuneiform wedge resection through a minimally invasive anterior approach without hip dislocation can be an easier alternative to restore proximal femoral anatomy in moderate to severe stable slips. Prospective case control studies are required to confirm these preliminary results.


Assuntos
Luxação do Quadril , Osteotomia/métodos , Escorregamento das Epífises Proximais do Fêmur/terapia , Seguimentos , Humanos , Estudos Prospectivos , Radiografia , Resultado do Tratamento
7.
Chem Res Toxicol ; 28(6): 1234-45, 2015 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-25933243

RESUMO

Glycation, an endogenous process that leads to the production of advanced glycation end products (AGEs), plays a role in the etiopathogenesis of different neurodegenerative diseases, such as Alzheimer's disease (AD). Methylglyoxal is the most potent precursor of AGEs, and high levels of methylglyoxal have been found in the cerebrospinal fluid of AD patients. Methylglyoxal may contribute to AD both inducing extensive protein cross-linking and mediating oxidative stress. The aim of this study was to investigate the role of sulforaphane, an isothiocyanate found in cruciferous vegetables, in counteracting methylglyoxal-induced damage in SH-SY5Y neuroblastoma cells. The data demonstrated that sulforaphane protects cells against glycative damage by inhibiting activation of the caspase-3 enzyme, reducing the phosphorylation of MAPK signaling pathways (ERK1/2, JNK, and p38), reducing oxidative stress, and increasing intracellular glutathione levels. For the first time, we demonstrate that sulforaphane enhances the methylglyoxal detoxifying system, increasing the expression and activity of glyoxalase 1. Sulforaphane modulated brain-derived neurotrophic factor and its pathway, whose dysregulation is related to AD development. Moreover, sulforaphane was able to revert the reduction of glucose uptake caused by methylglyoxal. In conclusion, sulforaphane demonstrates pleiotropic behavior thanks to its ability to act on different cellular targets, suggesting a potential role in preventing/counteracting multifactorial neurodegenerative diseases such as Alzheimer's.


Assuntos
Isotiocianatos/farmacologia , Fármacos Neuroprotetores/farmacologia , Aldeído Pirúvico/toxicidade , Apoptose/efeitos dos fármacos , Relação Dose-Resposta a Droga , Glucose/metabolismo , Humanos , Estresse Oxidativo/efeitos dos fármacos , Relação Estrutura-Atividade , Sulfóxidos , Células Tumorais Cultivadas
8.
Org Biomol Chem ; 13(22): 6291-8, 2015 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-25968655

RESUMO

Cellulose represents a key component of a renewable biomass source, from which chiral compounds with a high added value in the application for the synthesis of potentially bioactive molecules can be obtained. The anhydrosugar (1R,5S)-1-hydroxy-3,6-dioxa-bicyclo[3.2.1]octan-2-one (LAC), produced on the gram-scale by catalytic pyrolysis of cellulose, was used as a building block in the synthesis of five new enantiomerically pure muscarine-like products. The structures of the target compounds 4-8 showed different substituents at the C-2 and C-4 positions, but each of them had the same (2S,4R) configuration as the natural (+)-muscarine. A renewed interest in new muscarinic analogues is due to the design and synthesis of molecules exhibiting a higher selectivity for a specific muscarinic receptor and due to the development of effective agents in the treatment of Alzheimer's disease and other cognitive disorders. In this context, products 4-8 were investigated with respect to their binding affinity to human M1-M5 muscarinic acetylcholine receptors. The data indicated that compound 8, emerging as the most active in the series with values comparable to natural (+)-muscarine and a moderate selectivity in favor of the hM2 subtype receptor, also exhibited the highest stability during the interaction with the hM2 (3UON) subtype muscarinic receptor by using a docking calculation.


Assuntos
Compostos Bicíclicos Heterocíclicos com Pontes/química , Celulose/química , Muscarina/síntese química , Estrutura Molecular , Muscarina/química , Estereoisomerismo
9.
Environ Sci Technol ; 49(18): 11037-44, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26263378

RESUMO

The effect of biochar addition on the levels of black carbon (BC) and polcyclic aromatic hydrocarbons (PAHs) in a vineyard soil in central Italy was investigated within a two year period. Hydropyrolysis (HyPy) was used to determine the contents of BC (BCHyPy) in the amended and control soils, while the hydrocarbon composition of the semi-labile (non-BCHyPy) fraction released by HyPy was determined by gas chromatography-mass spectrometry, together with the solvent-extractable PAHs. The concentrations of these three polycyclic aromatic carbon reservoirs changed and impacted differently the soil organic carbon over the period of the trial. The addition of biochar (33 ton dry biochar ha(-1)) gave rise to a sharp increase in soil organic carbon, which could be accounted for by an increase in BCHyPy. Over time, the concentration of BCHyPy decreased significantly from 36 to 23 mg g(-1) and as a carbon percentage from 79% to 61%. No clear time trends were observed for the non-BCHyPy PAHs varying from 39 to 34 µg g(-1) in treated soils, not significantly different from control soils. However, the concentrations of extractable PAHs increased markedly in the amended soils and decreased with time from 153 to 78 ng g(-1) remaining always higher than those in untreated soil. The extent of the BCHyPy loss was more compatible with physical rather than chemical processes.


Assuntos
Carbono/análise , Carvão Vegetal , Hidrocarbonetos Policíclicos Aromáticos/análise , Poluentes do Solo/análise , Solo/química , Agricultura , Itália , Fuligem/análise , Fuligem/química
10.
J Struct Biol ; 185(1): 99-106, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24157843

RESUMO

The role of lipids in controlling water exchange is fundamentally a matter of molecular organization. In the present study we have observed that in snake molt the water permeability drastically varies among species living in different climates and habitats. The analysis of molts from four snake species: tiger snake, Notechis scutatus, gabon viper, Bitis gabonica, rattle snake, Crotalus atrox, and grass snake, Natrix natrix, revealed correlations between the molecular composition and the structural organization of the lipid-rich mesos layer with control in water exchange as a function of temperature. It was discovered, merging data from micro-diffraction and micro-spectroscopy with those from thermal, NMR and chromatographic analyses, that this control is generated from a sophisticated structural organization that changes size and phase distribution of crystalline domains of specific lipid molecules as a function of temperature. Thus, the results of this research on four snake species suggest that in snake skins different structured lipid layers have evolved and adapted to different climates. Moreover, these lipid structures can protect, "safety", the snakes from water lost even at temperatures higher than those of their usual habitat.


Assuntos
Lipídeos/fisiologia , Muda/fisiologia , Pele/metabolismo , Pele/fisiopatologia , Serpentes/metabolismo , Serpentes/fisiologia , Água/metabolismo , Animais , Ecossistema , Permeabilidade , Temperatura
11.
Anal Bioanal Chem ; 406(24): 6021-33, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25015043

RESUMO

Off-line analytical pyrolysis combined with gas chromatography­mass spectroscopy (GC­MS), directly or after trimethylsilylation, along with infrared spectroscopy and amino acid analysis was applied for the first time to the characterization of the intra-skeletal organic matrix (OM) extracted from four Mediterranean hard corals. They were diverse in growth form and trophic strategy namely Balanophyllia europaea and Leptopsammia pruvoti­solitary corals, only the first having zooxanthelle­and Cladocora caespitosa and Astroides calycularis­colonial corals, only the first with zooxanthelle. Pyrolysis products evolved from OM could be assigned to lipid (e.g. fatty acids, fatty alcohols, monoacylglicerols), protein (e.g. 2,5-diketopiperazines, DKPs) and polysaccharide (e.g. anhydrosugars) precursors. Their quantitative distribution showed for all the species a low protein content with respect to lipids and polysaccharides. A chemometric approach using principal component analysis (PCA) and clustering analysis was applied on OM mean amino acidic compositions. The small compositional diversity across coral species was tentatively related with coral growth form. The presence of N-acetyl glucosamine markers suggested a functional link with other calcified tissues containing chitin. The protein fraction was further investigated using novel DKP markers tentatively identified from analytical pyrolysis of model polar linear dipeptides. Again, no correlation was observed in relation to coral ecology. These analytical results revealed that the bulk structure and composition of OMs among studied corals are similar, as it is the textural organization of the skeleton mineralized units. Therefore, they suggest that coral's biomineralization is governed by similar macromolecules, and probably mechanisms, independently from their ecology.


Assuntos
Antozoários/química , Aminoácidos/análise , Animais , Antozoários/classificação , Polissacarídeos , Proteínas/análise
12.
Environ Pollut ; 319: 120951, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36581238

RESUMO

Bioplastics are promoted as safer alternatives to tackle the long-term persistence of conventional plastics. However, information on the potential release of additives and non-intentionally added substances (NIAS) in the surrounding environment is limited, and biological effects of the leachates have been little studied. Leachates produced from three bioplastics, i.e. compostable bags (CB), bio-polyethylene terephthalate bottles (bioPET) and polylactic acid cups (PLA), and a control polymeric material, i.e. rubber tire (TR), were examined. The chemical nature of bioplastic polyesters PET, PLA and poly (butylene adipate-co-terephthalate) (PBAT) in CB, was confirmed by analytical pyrolysis. Fragments were incubated in artificial sea water for 14 days at 20 °C in darkness and leachate contents examined by GC-MS and HPLC-MS/MS. Catalysts and stabilizers represented the majority of chemicals in TR, while NIAS (e.g. 1,6-dioxacyclododecane-7,12-dione) were the main components of CB. Bisphenol A occurred in all leachates at a concentration range 0.3-4.8 µg/L. Trace metals at concentrations higher than control water were found in all leachates, albeit more represented in leachates from CB and TR. A dose response to 11 dilutions of leachates (in the range 0.6-100%) was tested for biological effects on early embryo stages of Mytilus galloprovincialis. Embryotoxicity was observed in the whole range of tested concentrations, the magnitude of effect depending on the polymers. The highest concentrations caused reduction of egg fertilization (CB, bioPET, TR) and of larvae motility (CB, PLA, TR). TR leachates also provoked larvae mortality in the range 10-100%. Effects on adult mussel physiology were evaluated after a 7-day in vivo exposure to the different leachates at 0.6% concentration. Nine biomarkers concerning lysosomal functionality, neurotransmission, antioxidant and immune responses were assessed. All lysosomal parameters were affected, and serum lysozyme activity inhibited. Harmonized chemical and biological approaches are recommended to assess bioplastic safety and support production of sustainable bioplastics.


Assuntos
Mytilus , Espectrometria de Massas em Tandem , Animais , Larva , Plásticos/toxicidade , Poliésteres/toxicidade , Borracha , Polímeros/toxicidade , Mytilus/fisiologia
13.
Chemistry ; 18(45): 14367-74, 2012 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-22996327

RESUMO

Mineralized tissues grow through biologically controlled processes in which specific macromolecules are involved. Some of these molecules, which are present in very low concentrations and are difficult to localize and characterize, become entrapped inside the mineralized tissue. Herein, a protein fragment, GP, which was obtained by the alkaline digestion of the green sheet of the abalone shell, is used as a probe to study the changes in molecular structure that occur during the precipitation of calcium carbonate. This important goal was achieved by exploiting a fluorescent tag in GP. The experimental results that were obtained by using spectroscopic-, chromatographic-, and microscopic techniques indicate that GP controls the precipitation kinetics and morphology of calcium carbonate crystals, and that it only undergoes structural reorganization when entrapped inside calcium carbonate crystals. To the best of our knowledge, this report represents one of the first studies on the conformational changes of a protein fragment that is involved in biomineralization processes on moving from the solution phase into the mineral phase.


Assuntos
Carbonato de Cálcio/química , Proteínas/química , Animais , Cristalização , Corantes Fluorescentes/química , Gastrópodes , Proteínas/metabolismo , Espectrometria de Fluorescência
14.
Sci Total Environ ; 812: 151422, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34742976

RESUMO

Dissolved organic matter (DOM) is an important organic matter fraction that plays a key role in many biological and chemical processes in soil. The effect of biochar addition on the content and composition of soil organic matter (SOM) and DOM in an agricultural soil in Italy was investigated within a two-year period. UV-Vis spectroscopy and analytical pyrolysis have been applied to study complex components in DOM soil samples. Additionally, analytical pyrolysis was used to provide qualitative information of SOM at molecular level and the properties of biochar before and one year after amendment. A method was developed to quantify biochar levels by thermogravimetric analysis that enabled to identify deviations from the amendment rate. The water-soluble organic carbon (WSOC) concentrations in the amended soils were significantly lower than those in the control soils, indicating that biochar decreased the leaching of DOM. DOM in treated soils was characterized by a higher aromatic character according to analytical pyrolysis and UV-Vis spectroscopy. Moreover, a relatively high abundance of compounds with N was observed in pyrolysates of treated soils, suggesting that biochar increased the proportion of microbial DOM. The results from thermal and spectroscopy techniques are consistent in highlighting significant changes in DOM levels and composition due to biochar application with important effects on soil carbon storage and cycling.


Assuntos
Matéria Orgânica Dissolvida , Solo , Agricultura , Carvão Vegetal
15.
J Struct Biol ; 173(1): 128-37, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20705141

RESUMO

The interstitial green sheets in abalone shell nacre are shown to be bifacially differentiated trilaminate polymeric complexes, with glycoprotein layers sandwiching a central core containing chitin. They share some common feature with the organic matrix layers between the aragonite tablets in the nacre and the periostracum, and show similarities to the myostracum. Thus, although the green sheet is reported to be unique to the abalone shell, it represents an interesting model for the study of molluscan shell biomineralization processes. Indeed, during shell formation, prismatic and spherulitic aragonite precedes and follows the deposition of the interstitial green polymeric composite sheets, and there is evidence to suggest that these sheets demark the interruption of nacre synthesis and serve to nucleate the resumption of calcium carbonate crystal growth. The green polymeric interstitial sheet purified from the abalone shell was investigated by spectroscopic and imaging techniques: FTIR, confocal microscopy, scanning and transmission electron microscopy, and by pyrolysis combined with GC-MS. Structural and compositional differences are observed between the surfaces of the two sides of the interstitial polymeric composite sheets. Moreover, comparative crystallization experiments on the green sheet sides also reveal asymmetry with respect to the nucleation of calcium carbonate. These findings suggest that these bifacially differentiated interstitial composites may play an active role in the mineral assembly processes, with one of the surfaces acting as a crystal nucleator.


Assuntos
Estruturas Animais/química , Calcificação Fisiológica , Carbonato de Cálcio/química , Quitina/análise , Gastrópodes/anatomia & histologia , Glicoproteínas/análise , Animais , Carbonato de Cálcio/análise , Cromatografia Gasosa-Espectrometria de Massas , Gastrópodes/química , Microscopia Confocal , Microscopia Eletrônica , Polímeros/análise , Espectroscopia de Infravermelho com Transformada de Fourier
16.
Am J Physiol Heart Circ Physiol ; 300(6): H2196-205, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21478407

RESUMO

Ischemic preconditioning is a complex cardioprotective phenomenon that involves adaptive changes in cells and molecules and occurs in a biphasic pattern: an early phase after 1-2 h and a late phase after 12-24 h. While it is widely accepted that reactive oxygen species are strongly involved in triggering ischemic preconditiong, it is not clear if they play a major role in the early or late phase of preconditioning and which are the mechanisms involved. The present study was designed to investigate the mechanisms behind H(2)O(2)-induced cardioprotection in rat neonatal cardiomyocytes. We focused on antioxidant and phase II enzymes and their modulation by protein kinase signaling pathways and nuclear-factor-E(2)-related factor-1 (Nrf1) and Nrf2. H(2)O(2) preconditioning was able to counteract oxidative stress more effectively in the late than in the early phase of adaptation. In particular, H(2)O(2) preconditioning counteracted oxidative stress-induced apoptosis by decreasing caspase-3 activity, increasing Bcl2 expression and selectively increasing the expression and activity of antioxidant and phase II enzymes through Nrf1 and Nrf2 translocation to the nucleus. The downregulation of Nrf1 and Nrf2 by small interfering RNA reduced the expression level of phase II enzymes. Specific inhibitors of phosphatidylinositol 3-kinase/Akt and p38 MAPK activation partially reduced the cardioprotection elicited by H(2)O(2) preconditioning and the induction and activity of phase II enzymes. These findings demonstrate, for the first time, a key role for Nrf1, and not only for Nrf2, in the induction of phase II enzymes triggered by H(2)O(2) preconditioning.


Assuntos
Peróxido de Hidrogênio/farmacologia , Precondicionamento Isquêmico Miocárdico , Miócitos Cardíacos/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/fisiologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Caspase 3/metabolismo , Células Cultivadas , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Modelos Animais , Miócitos Cardíacos/citologia , Miócitos Cardíacos/efeitos dos fármacos , Fator 1 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Oxidantes/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Ratos , Ratos Wistar
17.
Amino Acids ; 40(2): 633-40, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20658159

RESUMO

(1R,5S)-1-hydroxy-3,6-dioxa-bicyclo[3.2.1]octan-2-one, is a bicyclic lactone obtained in gram-scale by catalytic pyrolysis of the renewable source cellulose. Now it has been used as a chiral building block in the preparation of the new δ-sugar amino acid, (3R,5S)-5-(aminoethyl)-3-hydroxytetrahydrofurane-3-carboxylic acid, by an efficient synthesis in five steps with a 67% overall yield. The structure of this tetrahydrofurane amino acid, isolated in protonated form, was assigned by extensive mono- and bidimensional (1)H- and (13)C-NMR analysis and mass spectrometry, including measurements by electrospray and matrix-assisted laser desorption ionization techniques, the latter one for high-resolution experiments. This amino acid is an isoster of dipeptide glycine-alanine (H-Gly-Ala-OH), with a potential use in the access of new peptidomimetics with conformationally restricted structures due to the presence of tetrahydrofurane ring. As a preliminary study in order to disclose this effect, density functional theory calculation performed in water using polar continuum model was applied to the new amino acid and H-Gly-Ala-OH dipeptide, so that to evaluate and compare the relative torsional angles for the energy-minimized structures.


Assuntos
Aminoácidos/química , Amino Açúcares/síntese química , Celulose/química , Furanos/química , Lactonas/química , Amino Açúcares/química , Estrutura Molecular
18.
Anal Bioanal Chem ; 399(9): 3081-91, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21069299

RESUMO

This study proposes FTIR spectroscopy in the far-infrared region (FarIR) as an alternative method for the characterisation of natural resins. To this purpose, standards of natural resins belonging to four different categories (sesquiterpenic, i.e. elemi, shellac; diterpenic, i.e. colophony, Venice turpentine; diterpenic with polymerised components, i.e. copal, sandarac; triterpenic, i.e. mastic and dammar) used as paint varnishes have been analysed by FarIR spectroscopy in ATR mode. Discrimination between spectral data and repeatability of measurements have been magnified and verified using principal component analysis, in order to verify the effectiveness of the method in distinguishing the four resin categories. The same samples were analysed in the MidIR range, but the spectral differences between the different categories were not evident. Moreover, the method has been tested on historical samples from the painting "La Battaglia di Cialdiran" (sixteenth century) and from a gilded leather (seventeenth century). In the first case, FarIR spectroscopy allowed confirmation of the results obtained by analytical pyrolysis. In the latter, FarIR spectroscopy proved successfully, effective in the identification of the superficial resin layer that could not be detected with the bulk chromatographic analyses.


Assuntos
Fatores Biológicos/química , Biopolímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Pintura/análise
19.
Acta Biomed ; 92(5): e2021312, 2021 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-34738584

RESUMO

PURPOSE: The aim of the present study was to review the outcome of the surgical treatment of 54 periprosthetic femoral fractures (PFF) after total hip arthroplasty at a mean follow-up of 45 months. At final follow-up, the clinical outcome was measured using the Harris Hip score (HHS), the Karnofsky score (KS), while, the radiographic results were evaluated using the Beals and Tower's criteria. RESULTS: There were 13 post-operative complications that occurred in 10 patients with an overall re-operation rate of 11%. At final follow-up the mean HHS was 64 (range 20-100) and the mean KS was 66 (range 30-100). The radiological results were excellent in 89%, good in 9% and poor 2% of patients. The mortality rate was 0% at 3 months and 3.7% at one year post-operatively. The mean last HHS and KS of patients older than 75 years or with comorbidities were lower than that of patients younger than 75 years or without comorbidities. CONCLUSIONS: Although this study have shown that the surgical treatment of PFF was associated with a low re-operative rate, a good to excellent radiological results and a low mortality rate at 3 months and 1 year postoperatively, there was a marked functional deterioration in many patients. This decline of function could be attributed to the advanced age of patients and the presence of comorbidities.


Assuntos
Artroplastia de Quadril , Fraturas do Fêmur , Prótese de Quadril , Fraturas Periprotéticas , Fraturas do Fêmur/diagnóstico por imagem , Fraturas do Fêmur/etiologia , Fraturas do Fêmur/cirurgia , Seguimentos , Humanos , Fraturas Periprotéticas/diagnóstico por imagem , Fraturas Periprotéticas/etiologia , Fraturas Periprotéticas/cirurgia , Reoperação , Estudos Retrospectivos , Resultado do Tratamento
20.
JBJS Case Connect ; 11(3)2021 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-34449448

RESUMO

CASE: We present a 36-year-old man with L1 burst fracture after a sneeze. He was in follow-up for indolent systemic mastocytosis (ISM), and osteoporosis was treated with bisphosphonate. Owing to neurologic impairment, posterior decompressive laminectomy and thoraco-lumbar fusion with cemented screws were performed. CONCLUSION: Vertebral fractures in young patients affected by ISM required a multidisciplinary approach and a careful preoperative planning to achieve acceptable results. These fractures are so rare that even an experienced spine surgeon may not come across them during his whole career. Nevertheless, diagnostic tool improvement makes its diagnosis more frequent, that is why every spine surgeon should know this disease.


Assuntos
Fraturas por Compressão , Mastocitose Sistêmica , Osteoporose , Fraturas da Coluna Vertebral , Adulto , Fraturas por Compressão/etiologia , Fraturas por Compressão/cirurgia , Humanos , Masculino , Mastocitose Sistêmica/complicações , Fraturas da Coluna Vertebral/etiologia , Fraturas da Coluna Vertebral/cirurgia , Coluna Vertebral
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