RESUMO
Trapped ions in radio-frequency traps are among the leading approaches for realizing quantum computers, because of high-fidelity quantum gates and long coherence times1-3. However, the use of radio-frequencies presents several challenges to scaling, including requiring compatibility of chips with high voltages4, managing power dissipation5 and restricting transport and placement of ions6. Here we realize a micro-fabricated Penning ion trap that removes these restrictions by replacing the radio-frequency field with a 3 T magnetic field. We demonstrate full quantum control of an ion in this setting, as well as the ability to transport the ion arbitrarily in the trapping plane above the chip. This unique feature of the Penning micro-trap approach opens up a modification of the quantum charge-coupled device architecture with improved connectivity and flexibility, facilitating the realization of large-scale trapped-ion quantum computing, quantum simulation and quantum sensing.
RESUMO
Psoralea corylifolia (syn. Cullen corylifolium), commonly called bawachi, is a medicinal plant extensively used for skin conditions like leukoderma, vitiligo, and psoriasis. It is notably rich in valuable bioactive compounds, particularly coumarins and furanocoumarins. This study isolated fourteen coumarins from P.â corylifolia which were tested for cytotoxicity using the MTT assay, with compound 10 showing good cytotoxicity against A549 cells (IC50 0.9â µM), while compound 1, compound 2, and compound 3 displaying potential cytotoxicity against MDA-MB-231 cells (IC50 0.49â µM, 0.56â µM, and 0.84â µM respectively). Additionally, the compounds' interaction with Epidermal Growth Factor Receptor (EGFR) protein, highly expressed in both cell lines, was investigated through molecular modeling studies, that aligned well with cytotoxicity results. The findings revealed the remarkable cytotoxic potential of four coumarins 1, 2, 3, and 10 against A549 and MDA-MB-231â cell lines.
Assuntos
Furocumarinas , Plantas Medicinais , Psoralea , Cumarínicos/farmacologia , Extratos Vegetais/farmacologiaRESUMO
Accurate and reliable quantification of organic acids with carboxylic acid functional groups in complex biological samples remains a major analytical challenge in clinical chemistry. Issues such as spontaneous decarboxylation during ionization, poor chromatographic resolution, and retention on a reverse-phase column hinder sensitivity, specificity, and reproducibility in multiple-reaction monitoring (MRM)-based LC-MS assays. We report a targeted metabolomics method using phenylenediamine derivatization for quantifying carboxylic acid-containing metabolites (CCMs). This method achieves accurate and sensitive quantification in various biological matrices, with recovery rates from 90% to 105% and CVs ≤ 10%. It shows linearity from 0.1 ng/mL to 10 µg/mL with linear regression coefficients of 0.99 and LODs as low as 0.01 ng/mL. The library included a wide variety of structurally variant CCMs such as amino acids/conjugates, short- to medium-chain organic acids, di/tri-carboxylic acids/conjugates, fatty acids, and some ring-containing CCMs. Comparing CCM profiles of pancreatic cancer cells to normal pancreatic cells identified potential biomarkers and their correlation with key metabolic pathways. This method enables sensitive, specific, and high-throughput quantification of CCMs from small samples, supporting a wide range of applications in basic, clinical, and translational research.
Assuntos
Ácidos Carboxílicos , Metabolômica , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/metabolismo , Metabolômica/métodos , Ácidos Carboxílicos/metabolismo , Ácidos Carboxílicos/análise , Cromatografia Líquida/métodos , Linhagem Celular Tumoral , Espectrometria de Massas/métodos , Espectrometria de Massas em Tandem/métodos , Reprodutibilidade dos Testes , Espectrometria de Massa com Cromatografia LíquidaRESUMO
The method for amide bond synthesis described here utilizes carboxylic acids and hydrazines in the presence of a catalytic amount of ZnCl2. This is the first report that highlights the use of hydrazine as an amine partner for amide synthesis directly with carboxylic acids. Ammonia (gas) is the only by-product in this method. The methodology is simple and could help in the synthesis of peptides and natural product derivatives.
RESUMO
Since long ago, medicinal plants have played a vital role in drug discovery. Being blessed and rich in chemovars with diverse scaffolds, they have unique characteristics of evolving based on the need. The World Health Organization also mentions that medicinal plants remain at the center for meeting primary healthcare needs as the population relies on them. The plant-derived natural products have remained an attractive choice for drug development owing to their specific biological functions relevant to human health and also the high degree of potency and specificity they offer. In this context, one such esteemed phytoconstituent with inexplicable biological potential is psoralen, a furanocoumarin. Psoralen was the first constituent isolated from the plant Psoralea corylifolia, commonly known as Bauchi. Despite being a life-saver for psoriasis, vitiligo, and leukoderma, it also showed immense anticancer, anti-inflammatory, and anti-osteoporotic potential. This review brings attention to the possible application of psoralen as an attractive target for rational drug design and medicinal chemistry. It discusses the various methods for the total synthesis of psoralen, its extraction, the pharmacological spectrum of psoralen, and the derivatization done on psoralen.
Assuntos
Fabaceae , Furocumarinas , Plantas Medicinais , Psoralea , Humanos , Furocumarinas/farmacologia , Ficusina/farmacologia , Extratos Vegetais/farmacologia , Compostos Fitoquímicos/farmacologiaRESUMO
Microtubules are appealing as intracellular targets for anticancer activity due to their importance in cell division. Three important binding sites are present on the tubulin protein: taxane, vinca, and colchicine binding sites (CBS). Many USFDA-approved drugs such as paclitaxel, ixabepilone, vinblastine, and combretastatin act by altering the dynamics of the microtubules. Additionally, a large number of compounds have been synthesized by medicinal chemists around the globe that target different tubulin binding sites. Although CBS inhibitors have proved their cytotoxic potential, no CBS-targeting drug had been able to reach the market. Several studies have reported design, synthesis, and biological evaluation of indole derivatives as potential anticancer agents. These compounds have been shown to inhibit cancer cell proliferation, induce apoptosis, and disrupt microtubule formation. Moreover, the binding affinity of these compounds to the CBS has been demonstrated using molecular docking studies and competitive binding assays. The present work has reviewed indole derivatives as potential colchicine-binding site inhibitors. The structure-activity relationship studies have revealed the crucial pharmacophoric features required for the potent and selective binding of indole derivatives to the CBS. The development of these compounds with improved efficacy and reduced toxicity could potentially lead to the development of novel and effective cancer therapies.
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Realizing spatiotemporal patterns out of a chemical reaction diffusion system remains an experimental challenge owing to the difficulty in overcoming the stringent condition of diffusion driven instability. Herein, by considering the spatially extended Gray-Scott model system, we have investigated how the cross diffusivities of the reactants involved influence the nature and dynamics of spatiotemporal patterns. Our study unravels that in absence of diffusion driven instability, spatially inhomogeneous patterns can be obtained for the Gray-Scott model system, and unstable time dependent patterns can be stabilized just by adjusting cross diffusivities of the reactants. Interestingly, the effect of cross diffusion in presence of the diffusion driven instability can differentially alter the speed of pattern formation, and potentially modify the nature of the spatiotemporal patterns obtained under different parametric conditions. Experimental verification of our findings may allow us to observe spatiotemporal patterns beyond the regime of classical Turing instability.
RESUMO
Rapid assessment of radiation signatures in noninvasive biofluids may aid in assigning proper medical treatments for acute radiation syndrome (ARS) and delegating limited resources after a nuclear disaster. Metabolomic platforms allow for rapid screening of biofluid signatures and show promise in differentiating radiation quality and time postexposure. Here, we use global metabolomics to differentiate temporal effects (1-60 d) found in nonhuman primate (NHP) urine and serum small molecule signatures after a 4 Gy total body irradiation. Random Forests analysis differentially classifies biofluid signatures according to days post 4 Gy exposure. Eight compounds involved in protein metabolism, fatty acid ß oxidation, DNA base deamination, and general energy metabolism were identified in each urine and serum sample and validated through tandem MS. The greatest perturbations were seen at 1 d in urine and 1-21 d in serum. Furthermore, we developed a targeted liquid chromatography tandem mass spectrometry (LC-MS/MS) with multiple reaction monitoring (MRM) method to quantify a six compound panel (hypoxanthine, carnitine, acetylcarnitine, proline, taurine, and citrulline) identified in a previous training cohort at 7 d after a 4 Gy exposure. The highest sensitivity and specificity for classifying exposure at 7 d after a 4 Gy exposure included carnitine and acetylcarnitine in urine and taurine, carnitine, and hypoxanthine in serum. Receiver operator characteristic (ROC) curve analysis using combined compounds show excellent sensitivity and specificity in urine (area under the curve [AUC] = 0.99) and serum (AUC = 0.95). These results highlight the utility of MS platforms to differentiate time postexposure and acquire reliable quantitative biomarker panels for classifying exposed individuals.
Assuntos
Acetilcarnitina/urina , Síndrome Aguda da Radiação/diagnóstico , Carnitina/urina , Hipoxantina/sangue , Metabolômica/métodos , Taurina/sangue , Irradiação Corporal Total/métodos , Acetilcarnitina/sangue , Síndrome Aguda da Radiação/sangue , Síndrome Aguda da Radiação/patologia , Síndrome Aguda da Radiação/urina , Animais , Biomarcadores/sangue , Biomarcadores/urina , Carnitina/sangue , Cromatografia Líquida , Citrulina/sangue , Citrulina/urina , Metabolismo Energético/genética , Metabolismo Energético/efeitos da radiação , Ácidos Graxos/sangue , Ácidos Graxos/urina , Feminino , Hipoxantina/urina , Macaca mulatta , Masculino , Espectrometria de Massas , Metaboloma/genética , Metaboloma/efeitos da radiação , Prolina/sangue , Prolina/urina , Biossíntese de Proteínas/efeitos da radiação , Curva ROC , Taurina/urinaRESUMO
Santonin, a natural product, was aromatized with molecular iodine as the catalyst. The new compound was characterized as ( S)-methyl-2-(7-hydroxy-5,8-dimethylnaphthalen-2-yl) propanoate (2) based on 2D NMR spectroscopic data. Structurally, compound 2 was highly similar to the anti-inflammatory drug naproxen. The new naproxen analogue had significant potency against cyclooxygenase 1 and 2 (IC50 = 31.0 and 66.1 µM, respectively).
Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Anti-Inflamatórios/farmacologia , Ciclo-Oxigenase 1/química , Ciclo-Oxigenase 2/química , Inibidores de Ciclo-Oxigenase/farmacologia , Naproxeno/farmacologia , Santonina/farmacologia , Anti-Inflamatórios/química , Anti-Inflamatórios não Esteroides/química , Ciclo-Oxigenase 1/metabolismo , Ciclo-Oxigenase 2/metabolismo , Inibidores de Ciclo-Oxigenase/química , Estrutura Molecular , Naproxeno/química , Santonina/químicaRESUMO
Aggregation/misfolding of α-synuclein and ßA4 proteins cause neuronal cell death (NCD) associated with Parkinson's and Alzheimer's disease. It has been suggested that a heat shock protein-90 (Hsp90) inhibitor can prevent NCD by activating the heat shock transcription factor-1 which, in turn, upregulates molecular chaperones such as Hsp70 that targets aggregated/misfolded proteins for refolding/degradation. We have isolated radicicol, an Hsp90 inhibitor, from a fungus occurring in the crevices of marble rocks of Central India. Radicicol, which was found to be a strong antioxidant, was tested for its ability to rescue yeast cells from death induced by expression of wild-type α-synuclein, its more toxic A53T mutant, and ßA4. It effectively overcomes wild-type/mutant α-synuclein mediated yeast cell death, concomitantly diminishes ROS levels, reverses mitochondrial dysfunction and prevents nuclear DNA-fragmentation, a hallmark of apoptosis. Surprisingly however, radicicol is unable to rescue yeast cells from death triggered by expression of secreted ßA4. Moreover, although radicicol acts as an antioxidant it fails to prevent yeast cell death inflicted by the proapoptotic protein, Bax. Our results indicate that radicicol specifically targets aggregated/misfolded α-synuclein's toxicity and opens up the possibility of using multiple yeast assays to screen natural product libraries for compounds that would unambiguously target α-synuclein aggregation/misfolding.
Assuntos
Peptídeos beta-Amiloides/metabolismo , Apoptose/efeitos dos fármacos , Sequestradores de Radicais Livres/farmacologia , Macrolídeos/farmacologia , alfa-Sinucleína/metabolismo , Proteína X Associada a bcl-2/metabolismo , Peptídeos beta-Amiloides/genética , Sequestradores de Radicais Livres/isolamento & purificação , Sequestradores de Radicais Livres/metabolismo , Humanos , Macrolídeos/isolamento & purificação , Macrolídeos/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/metabolismo , Simulação de Acoplamento Molecular , Mutação , Ligação Proteica , Espécies Reativas de Oxigênio/metabolismo , Saccharomyces cerevisiae/genética , Sordariales/química , alfa-Sinucleína/genética , Proteína X Associada a bcl-2/genéticaRESUMO
Patients presenting with prostate cancers undergo clinical staging evaluations to determine the extent of disease to guide therapeutic recommendations. Management options may include watchful waiting, surgery, or radiation therapy. Thus, initial risk stratification of prostate cancer patients is important for achieving optimal therapeutic results or cancer cure and preservation of quality of life. Predictive biomarkers for risks of complications or late effects of treatment are needed to inform clinical decisions for treatment selection. Here, we analyzed pre-treatment plasma metabolites in a cohort of prostate cancer patients (N = 99) treated with Stereotactic Body Radiation Therapy (SBRT) at Medstar-Georgetown University Hospital in a longitudinal, quality-of-life study to determine if individuals experiencing radiation toxicities can be identified by a molecular profile in plasma prior to treatment. We used a multiple reaction mass spectrometry-based molecular phenotyping of clinically annotated plasma samples in a retrospective outcome analysis to identify candidate biomarker panels correlating with adverse clinical outcomes following radiation therapy. We describe the discovery of candidate biomarkers, based on small molecule metabolite panels, showing high correlations (AUCs ≥ 95%) with radiation toxicities, suitable for validation studies in an expanded cohort of patients.
Assuntos
Biomarcadores , Neoplasias da Próstata , Lesões por Radiação , Radiocirurgia , Biomarcadores/sangue , Humanos , Estudos Longitudinais , Masculino , Neoplasias da Próstata/radioterapia , Qualidade de Vida , Lesões por Radiação/sangue , Radiocirurgia/efeitos adversos , Estudos RetrospectivosRESUMO
The development of multi-drug resistance to existing anticancer drugs is one of the major challenges in cancer treatment. The over-expression of cytochrome P450 1B1 enzyme has been reported to cause resistance to cisplatin. With an objective to discover cisplatin-resistance reversal agents, herein, we report the evaluation of Glycyrrhiza glabra (licorice) extracts and its twelve chemical constituents for inhibition of CYP1B1 (and CYP1A1) enzyme in Sacchrosomes and live human cells. The hydroalcoholic extract showed potent inhibition of CYP1B1 in both Sacchrosomes as well as in live cells with IC50 values of 21 and 16⯵g/mL, respectively. Amongst the total of 12 constituents tested, quercetin and glabrol showed inhibition of CYP1B1 in live cell assay with IC50 values of 2.2 and 15⯵M, respectively. Both these natural products were found to be selective inhibitors of CYP1B1, and does not inhibit CYP2 and CYP3 family of enzymes (IC50â¯>â¯20⯵M). The hydroalcoholic extract of G. glabra and quercetin (4) showed complete reversal of cisplatin resistance in CYP1B1 overexpressing triple negative MDA-MB-468 breast cancer cells. The selective inhibition of CYP1B1 by quercetin and glabrol over CYP2 and CYP3 family of enzymes was studied by molecular modeling studies.
Assuntos
Antineoplásicos/farmacologia , Citocromo P-450 CYP1B1/antagonistas & inibidores , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Inibidores Enzimáticos/química , Glycyrrhiza/química , Extratos Vegetais/química , Quercetina/farmacologia , Sítios de Ligação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cisplatino/farmacologia , Citocromo P-450 CYP1B1/metabolismo , Inibidores Enzimáticos/farmacologia , Feminino , Glycyrrhiza/metabolismo , Humanos , Concentração Inibidora 50 , Simulação de Acoplamento Molecular , Extratos Vegetais/farmacologia , Estrutura Terciária de Proteína , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
Muscodor spp. are proficient producers of bioactive volatile organic compounds (VOCs) with many potential applications. However, all members of this genus produce varying amounts and types of VOCs which suggests the involvement of epigenetics as a possible explanation. The members of this genus are poorly explored for the production of soluble compounds (extrolites). In this study, the polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) genes from an endophyte, Muscodor yucatanensis Ni30, were cloned and sequenced. The PKS genes belonged to reduced, partially reduced, non-reduced, and highly reduced subtypes. Strains over-expressing PKS genes were developed through the use of small-molecule epigenetic modifiers (suberoylanilide hydroxamic acid (SAHA) and 5-azacytidine). The putative epigenetic variants of this organism differed considerably from the wild type in morphological features and cultural characteristics as well as metabolites that were produced. Each variant produced a different set of VOCs distinct from the wild type, and several VOCs including methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)hexane-2,4-diol and 2-carboxymethyl-3-n-hexylmaleic appeared in the variant strains, the production of which could be attributed to the activity of otherwise silent PKS genes. The bioactive extrolite brefeldin A was isolated and characterized from the wild type. However, this metabolite was not detected in EV-1, but instead, two other products were isolated and characterized as ergosterol and xylaguaianol C. Hence, M. yucatanensis has the genetic potential to produce several previously undetectable VOCs and organic solvent soluble products. It is also the case that small-molecule epigenetic modifiers can be used to produce stable variant strains of fungi with the potential to produce new molecules. Finally, this work hints to the prospect that the epigenetics of an endophytic microorganism can be influenced by any number of environmental and chemical factors associated with its host plant which may help to explain the enormous chemical diversity of secondary metabolic products found in Muscodor spp.
Assuntos
Endófitos/enzimologia , Endófitos/genética , Epigenômica , Regulação Fúngica da Expressão Gênica/genética , Metabolismo Secundário/genética , Xylariales/enzimologia , Xylariales/genética , Sequência de Aminoácidos , Azacitidina/metabolismo , Brefeldina A/metabolismo , DNA Fúngico , Endófitos/metabolismo , Ergosterol/metabolismo , Genes Fúngicos , Ácidos Hidroxâmicos/metabolismo , Peptídeo Sintases/química , Peptídeo Sintases/genética , Fenótipo , Filogenia , Policetídeo Sintases/química , Policetídeo Sintases/genética , Reação em Cadeia da Polimerase/métodos , Conformação Proteica , Alinhamento de Sequência , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismo , Vorinostat , Xylariales/classificação , Xylariales/metabolismoRESUMO
Rohitukine is a chromone alkaloid isolated from an Indian medicinal plant Dysoxylum binectariferum. This natural product has led to the discovery of two clinical candidates (flavopiridol and P276-00) for the treatment of cancer. Herein, for the first time we report an efficient protocol for isolation and purification of this precious natural product in a bulk-quantity from leaves (a renewable source) of D. binectariferum (>98% purity) without use of chromatography or any acid-base treatment. Despite of the fact that this scaffold has reached up to clinical stage, particularly for leukemia; however the antileukemic activity of a parent natural product has never been investigated. Furthermore, rohitukine has never been studied for cyclin-dependent kinase (Cdk) inhibition, kinase profiling and for its experimental physicochemical properties. Thus, herein, we report in vitro cytotoxicity of rohitukine in a panel of 20 cancer cell lines (including leukemia, pancreatic, prostate, breast and CNS) and 2 normal cell lines; kinase profiling, Cdk2/9 inhibition, and physicochemical properties (solubility and stability in biological medias, pKa, LogP, LogD). In cytotoxicity screening, rohitukine displayed promising activity in HL-60 and Molt-4 (leukemia) cell lines with GI50 of 10 and 12µM, respectively. It showed inhibition of Cdk2/A and Cdk9/T1 with IC50 values of 7.3 and 0.3µM, respectively. The key interactions of rohitukine with Cdk9 was also studied by molecular modeling. Rohitukine was found to be highly water soluble (Swater=10.3mg/mL) and its LogP value was -0.55. The ionization constant of rohitukine was found to be 5.83. Rohitukine was stable in various biological media's including rat plasma. The data presented herein will help in designing better anticancer agents in future.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Cromonas/farmacologia , Quinases Ciclina-Dependentes/antagonistas & inibidores , Meliaceae/química , Piperidinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Físico-Química , Cromonas/química , Cromonas/isolamento & purificação , Quinases Ciclina-Dependentes/metabolismo , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Modelos Moleculares , Estrutura Molecular , Piperidinas/química , Piperidinas/isolamento & purificação , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/isolamento & purificação , Relação Estrutura-AtividadeRESUMO
An LC/MS method has been developed for the simultaneous quantification of five flavonoids, i.e., mosloflavone, negletein, gardenin B, 5-methoxy-6,7-methylenedioxyflavone, and 5,6,7-trimethoxyflavone, in different ultrasound assisted solvent extracts of Actinocarya tibetica. The chromatographic separation was achieved on a Chromolith Speed ROD RP-18e column with gradient elution using methanol and 0.1% formic acid in water. The calibration curves of all five analytes showed good linearity (R2>0.991). Accuracy and precision were within the required limits. The developed method could serve as an effective method for QC of A. tibetica. The investigated compounds were determined simultaneously for the first time in A. tibetica or any other plant.
Assuntos
Altitude , Boraginaceae/química , Cromatografia Líquida/métodos , Flavonoides/análise , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas em Tandem/métodosAssuntos
Diabetes Mellitus , Leucoplasia Oral , Humanos , Índia , Lipídeos , Centros de Atenção TerciáriaRESUMO
Camptothecin (CPT, 1) is a potent anticancer natural product which led to the discovery of two clinically used anticancer drugs topotecan and irinotecan. These two drugs are semisynthetic analogs of CPT, and thus the commercial production of CPT as a raw material from various plant sources and tissue culture methods is highly demanding. In the present study, the Dysoxylum binectariferum bark, was identified as an alternative source of CPT, through bioassay-guided isolation. The barks showed presence of CPT (1) and its 9-methoxy analog 2, whereas CPT alkaloids were not present in seeds and leaves. This is the first report on isolation of CPT alkaloids from Meliaceae family. An efficient chromatography-free protocol for enrichment and isolation of CPT from D. binectariferum has been established, which was able to enrich CPT up to 21% in the crude extract. The LCMS (MRM)-based quantification method revealed the presence of 0.105% of CPT in dry barks of D. binectariferum. The discovery of CPT from D. binectariferum bark will certainly create a global interest in cultivation of this plant as a new crop for commercial production of CPT. Isolation of anticancer drug CPT from this plant, indicates that along with rohitukine, CPT and 9-methoxy CPT also contributes significantly to the cytotoxicity of D. binectariferum.
Assuntos
Antineoplásicos Fitogênicos/isolamento & purificação , Antineoplásicos Fitogênicos/farmacologia , Camptotecina/isolamento & purificação , Camptotecina/farmacologia , Meliaceae/química , Casca de Planta/química , Antineoplásicos Fitogênicos/química , Camptotecina/química , Proliferação de Células/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HL-60 , Humanos , Espectrometria de Massas , Conformação Molecular , Relação Estrutura-AtividadeRESUMO
A new method for synthesis of amides and hydroxamic acids from nitroarenes and aldehydes is described. The MnO2 catalyzed thermal deoxygenation of nitrobenzene resulted in formation of a reactive nitroso intermediate which on reaction with aldehydes provided amides and hydroxamic acids. The thermal neat reaction in the presence of 0.01 mmol KOH predominantly led to formation of hydroxamic acid whereas reaction in the presence of 1 mmol acetic acid produced amides as the only product.
Assuntos
Amidas/síntese química , Ácidos Hidroxâmicos/síntese química , Nitrobenzenos/química , Amidas/química , Ácidos Hidroxâmicos/química , Estrutura MolecularRESUMO
BACKGROUND: To evaluate the outcomes of single pass thin lenticule sutureless Descemet's stripping automated endothelial keratoplasty with donor lenticules prepared using a 400 µm microkeratome head. DESIGN: Interventional case series. PARTICIPANTS: Cases with corneal endothelial dysfunction. METHODS: Fifteen cases with corneal endothelial dysfunction (eight pseudophakic bullous keratopathy, three Fuchs' endothelial dystrophy, three congenital hereditary endothelial dystrophy and one failed graft) underwent thin lenticule Descemet's stripping automated endothelial keratoplasty at a tertiary care hospital. Donor lenticule was prepared with a single pass 400 µm Carriazo Barraquer microkeratome (Moria, Antony, France) head. Sutureless Descemet's stripping automated endothelial keratoplasty was performed in all the cases through a 3.5 mm corneoscleral tunnel using a Busin glide for graft insertion. MAIN OUTCOME MEASURES: Main parameters evaluated were postoperative donor lenticule thickness and best-corrected visual acuity. RESULTS: Donor lenticules were harvested successfully for all 15 cases without any complications. At 6-months follow up, the mean logMAR best-corrected visual acuity improved from 1.87 ± 0.52 to 0.109 ± 0.11 (P = < 0.0001). The mean donor lenticule thickness was 111 ± 17.62 µm (range 70-134 µm) at the last follow up. The mean endothelial cell loss was 26.33 ± 1.34%. CONCLUSIONS AND RELEVANCE: Thin donor lenticules for Descemet's stripping automated endothelial keratoplasty can be safely harvested using a single pass technique with 400 µm microkeratome head and can be used for a successful Descemet's stripping automated endothelial keratoplasty surgery.