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1.
Chem Commun (Camb) ; 58(96): 13298-13316, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-36382511

RESUMO

Organoboron compounds have a wide-range of applications in synthetic methodologies, natural products, and bioactive molecule synthesis. The sensitivity of boronic acid toward most synthetic reagents makes it necessary to introduce a protecting group before its utilization. Benchtop stable MIDA boronates have been found compatible with various common synthetic reagents which opens the doors for the synthesis of various small building blocks, natural products, and bioactive compounds. MIDA boronate compounds have been extensively utilized in Suzuki Miyaura coupling and Iterative cross-coupling reactions for the total synthesis of bioactive molecules and polymerization reactions. Different MIDA boronate compounds like vinyl, acyl, formyl, acrylic, and α-carbonyl MIDA boronates also act as novel synthetic building blocks for various synthetic transformations in organic synthesis. This paper summarizes the importance of MIDA boronate compounds in various aspects of organic chemistry.


Assuntos
Produtos Biológicos , Iminoácidos , Iminoácidos/química , Ácidos Borônicos/química , Técnicas de Química Sintética
2.
Medicina (Kaunas) ; 58(10)2022 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-36295494

RESUMO

Background and objectives-Chronic viral hepatitis B and C infections are one of the leading causes of chronic liver impairment, resulting in liver fibrosis and liver cirrhosis. An early diagnosis with accurate liver fibrosis staging leads to a proper diagnosis, thus tailoring correct treatment. Both invasive and noninvasive techniques are used in the diagnosis and staging of chronic liver impairment. Those techniques include liver biopsy, multiple serological markers (as either single tests or combined panels), and imaging examinations, such as ultrasound or magnetic resonance elastography. Nuclear medicine probes may also be employed in staging liver fibrosis, although the literature scarcely reports this. The purpose of our study was to investigate whether a dynamic liver scintigraphy with [99mTc]Tc-mebrofenin has any value in staging or grading chronic liver damage. Materials and Methods-We prospectively enrolled patients with chronic viral hepatitis B and C infection referred for liver biopsy. All patient underwent dynamic liver scintigraphy with 99mTc-mebrofenin prior to liver biopsy. Dynamic liver scintigraphy was performed immediately after intravenous tracer injection for 30 min scanning time. Multiple scintigraphy parameters were calculated (whole liver lobe and focal area time to peak (TTP), 30 min to peak ratio (30/peak), whole lobe and focal area slope index in 350 s (slope_350). Liver biopsy took place shortly after imaging. Results-We found that many dynamic scintigraphic parameters are positively or negatively associated with different stages of liver fibrosis. The main parameters that showed most value are the ratio between 30 min and the peak of the dynamic curve (30/peak_dex (ratio)), and liver clearance corrected for body surface area and liver area (LCL_m2_dm2 (%/min/m2/dm2)). Conclusions-Our present study proves that conducting dynamic liver scintigraphies with [99mTc]Tc-mebrofenin has potential value in staging liver fibrosis. The benefits of this method, including whole liver imaging and direct imaging of the liver function, provide an advantage over presently used quantitative imaging modalities.


Assuntos
Hepatite Viral Humana , Hepatopatias , Humanos , Iminoácidos , Compostos Radiofarmacêuticos , Tomografia Computadorizada por Raios X , Fígado/patologia , Cirrose Hepática/complicações , Cirrose Hepática/diagnóstico por imagem
3.
Chem Commun (Camb) ; 58(64): 8974-8977, 2022 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-35861309

RESUMO

A new method for the synthesis of (hetero)aryl nitriles via iminyl radicals has been developed through the electrochemical oxidative decarboxylation of α-imino-oxy acids. This protocol provides an efficient approach to nitriles with a broad range of functional-group tolerance under ambient conditions and can be applied for one-pot gram-scale synthesis.


Assuntos
Iminoácidos , Nitrilas , Catálise , Descarboxilação , Estresse Oxidativo
4.
J Laparoendosc Adv Surg Tech A ; 32(7): 794-799, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35404140

RESUMO

Introduction: Biliary dyskinesia is typically defined as a gallbladder ejection fraction (EF) <35% on hepatobiliary iminodiacetic acid scan with cholecystokinin stimulation (CCK-HIDA) testing. Cholecystectomy often leads to resolution of associated biliary colic symptoms. Alternatively, there is a subset of symptomatic patients with normal gallbladder EF on CCK-HIDA. It has been proposed that pain with CCK injection is more predictive of symptom resolution after cholecystectomy than low gallbladder EF. We reviewed our experience with pediatric patients with positive CCK provocation testing and a normal gallbladder EF in the absence of gallstones. Materials and Methods: We retrospectively reviewed the records of all pediatric patients with normal hepatobiliary iminodiacetic acid EFs (35%-80%) and pain with CCK injection at a tertiary care center between 2016 and 2020. Age, gender, body mass index (BMI), CCK-HIDA results, and pathology analysis were noted. Short- and long-term resolution of symptoms was determined by patient self-reporting at a mean of 3 weeks and 46 months, respectively. Results: Seventeen patients met inclusion criteria. Average age was 15.1 years (range, 12-17 years) with median BMI 24.9 (± 4.9 kg/m2). Mean CCK-HIDA EF was 56.3% (± 11.4%). In total, 62.5% of patients had evidence of chronic cholecystitis and/or cholesterolosis on pathology analysis. Of patients available for short-term and long-term postoperative follow-up, 80% and 83% reported complete or near complete resolution of symptoms, respectively. Conclusions: Normokinetic biliary dyskinesia is poorly understood but appears to be associated with chronic inflammation and cured by surgical intervention. Laparoscopic cholecystectomy results in resolution of symptoms for a majority of patients and should be considered in those with pain with CCK injection despite normal imaging studies. Clinical Trial Registration Number: 1657640-2.


Assuntos
Discinesia Biliar , Colecistectomia Laparoscópica , Adolescente , Criança , Humanos , Discinesia Biliar/cirurgia , Colecistectomia , Colecistectomia Laparoscópica/efeitos adversos , Colecistectomia Laparoscópica/métodos , Colecistocinina , Iminoácidos , Dor , Estudos Retrospectivos
5.
Mol Pharm ; 19(3): 853-861, 2022 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-35142223

RESUMO

Malignant pleural mesothelioma (MPM) is one of the intractable cancers that require a more effective therapeutic strategy for clinical practice. Hyaluronic acid (HA) nanogels were prepared by the chelation of cisplatin (CDDP) with different molecular weights of iminodiacetic acid-conjugated hyaluronic acid (HA-IDA). The sizes of the 100, 850, and 2000 kDa HA nanogels were 33, 43, and 44 nm, respectively. MSTO-211H, a human MPM cell line, was more effective in taking up all three HA nanogels compared to AB22, a mouse MPM cell line. In addition, the 850 kDa HA nanogel showed higher anticancer activity against AB22 and MSTO-211H than 100 and 2000 kDa HA nanogels. Furthermore, all the HA nanogels showed a milder cytotoxic effect on normal Met-5A mesothelial cells compared to that exhibited by free CDDP. Finally, the 850 kDa HA nanogel was administrated intrapleurally into both the MSTO-211H xenograft and AB22 allograft mouse models of MPM using an injectable HA-based hydrogel. HA nanogels showed a significant therapeutic effect in both the xenograft and allograft models.


Assuntos
Cisplatino , Mesotelioma Maligno , Animais , Linhagem Celular Tumoral , Cisplatino/farmacologia , Cisplatino/uso terapêutico , Humanos , Ácido Hialurônico , Iminoácidos , Camundongos , Nanogéis
6.
Amino Acids ; 54(5): 687-719, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35192062

RESUMO

Naturally occurring secondary amino acids, with proline as the main representative, contain an alpha-imino group in a cycle that is typically four-, five-, and six-membered. The unique ring structure exhibits exceptional properties-conformational rigidity, chemical stability, and specific roles in protein structure and folding. Many proline analogues have been used as valuable compounds for the study of metabolism of both prokaryotic and eukaryotic cells and for the synthesis of compounds with desired biological, pharmaceutical, or industrial properties. The D-forms of secondary amino acids play different roles in living organisms than the L-forms. They have different metabolic pathways, biological, physiological, and pharmacological effects, they can be indicators of changes and also serve as biomarkers of diseases. In the scientific literature, the number of articles examining D-amino acids in biological samples is increasing. The review summarises information on the occurrence and importance of D- and L-secondary amino acids-azetidic acid, proline, hydroxyprolines, pipecolic, nipecotic, hydroxypipecolic acids and related peptides containing these D-AAs, as well as the main analytical methods (mostly chromatographic) used for their enantiomeric determination in different matrices (biological samples, plants, food, water, and soil).


Assuntos
Aminoácidos , Iminoácidos , Aminoácidos/química , Iminoácidos/química , Peptídeos , Prolina/química , Estereoisomerismo
7.
IEEE Trans Cybern ; 52(11): 11698-11708, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33983891

RESUMO

Reducing domain divergence is a key step in transfer learning. Existing works focus on the minimization of global domain divergence. However, two domains may consist of several shared subdomains, and differ from each other in each subdomain. In this article, we take the local divergence of subdomains into account in transfer. Specifically, we propose to use the low-dimensional manifold to represent the subdomain, and align the local data distribution discrepancy in each manifold across domains. A manifold maximum mean discrepancy (M3D) is developed to measure the local distribution discrepancy in each manifold. We then propose a general framework, called transfer with manifolds discrepancy alignment (TMDA), to couple the discovery of data manifolds with the minimization of M3D. We instantiate TMDA in the subspace learning case considering both the linear and nonlinear mappings. We also instantiate TMDA in the deep learning framework. Experimental studies show that TMDA is a promising method for various transfer learning tasks.


Assuntos
Algoritmos , Iminoácidos , Morfolinas
8.
Curr Probl Diagn Radiol ; 51(2): 282-287, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33483187

RESUMO

Hepatobiliary iminodiacetic acid (HIDA) scan is one of the principal imaging modalities for the evaluation of the gallbladder and biliary tree. Congenital biliary anomalies are rare and can be difficult to recognize on HIDA scan. They may also mimic other biliary pathology. The purpose of this article is to review the spectrum of congenital gallbladder and biliary anomalies and describe their imaging appearance on HIDA scan. In addition, the diagnostic utility of functional imaging with HIDA when evaluating biliary tract anomalies is described.


Assuntos
Sistema Biliar , Vesícula Biliar , Sistema Biliar/diagnóstico por imagem , Vesícula Biliar/diagnóstico por imagem , Humanos , Iminoácidos
9.
J Hazard Mater ; 425: 127802, 2022 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-34896724

RESUMO

The rare earth elements being toxic in nature are being accumulated in water bodies as their industrial usage is growing exponentially, thus their efficient separation holds an immense significance. Herein, ligand functionalized metal organic framework (MOF), Phosphonomethyl iminodiacetic acid coordinated at Fe-BTC, was synthesized post-synthetically and incorporated subsequently in polyacrylonitrile polymer to prepare the composite beads via nonsolvent induced-phase-inversion technique for selective adsorption of La(III) from the wastewater in batch and dynamic column mode. XPS NMR, and FTIR were used to establish the interaction between functionalized ligand and unsaturated metal nodes of MOF. The adsorption capacity was 232.5 mg/g and 77.51 mg/g at 298 K of the functionalized MOF and composite beads respectively. Adsorption kinetics followed a pseudo-second order rate equation, and isotherm indicated the best fitting with Langmuir model. The dynamic behavior of the adsorption column packed with MOF/Polymer beads was fairly described by the Thomas model. The breakthrough time of 23.2 h could be attained with 12 cm of bed height and 10 ml/min of flow rate. These MOF/Polymer beads shown the selectivity of La over transitional metals were recycled over 5 times with about 15% loss of adsorption capacity. The findings provide suggestive insights of the potential use of functionalized MOF towards the separation of the rare earth element.


Assuntos
Estruturas Metalorgânicas , Poluentes Químicos da Água , Adsorção , Iminoácidos , Cinética , Poluentes Químicos da Água/análise
10.
Mikrochim Acta ; 188(12): 417, 2021 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-34762162

RESUMO

A three-step strategy is introduced to develop inherent iminodiacetic (IDA)-functionalized nanopolymer. SEM micrographs show homogenous spherical beads with a particle size of 500 nm. Further modification to COOH-functionalized 1,2-epoxy-5-hexene/DVB mesoporous nanopolymer enriches glycopeptides via hydrophilic interactions followed by their MS determination. Significantly high BET surface area 433.4336 m2 g-1 contributes to the improved surface hydrophilicity which is also shown by high concentration of ionizable carboxylic acids, 14.59 ± 0.25 mmol g-1. Measured surface area is the highest among DVB-based polymers and in general much higher in comparison to the previously reported BET surface areas of co-polymers, terpolymers, MOFs, and graphene-based composites. Thirty-one, 19, and 16 N-glycopeptides are enriched/identified by nanopolymer beads from tryptic digests of immunoglobulin G, horseradish peroxidase, and chicken avidin, respectively, without additional desalting steps. Material exhibits high selectivity (1:400 IgG:BSA), sensitivity (down to 0.1 fmol), regeneration ability up to three cycles, and batch-to-batch reproducibility (RSD > 1%). Furthermore, from 1 µL of digested human serum, 343 N-glycopeptide characteristics of 134 glycoproteins including 30 FDA-approved serum biomarkers are identified via nano-LC-MS/MS. The developed strategy to self-generate IDA on polymeric surface with improved surface area, porosity, and ordered morphology is insignia of its potential as chromatographic tool contributing to future developments in large-scale biomedical glycoproteomics studies.


Assuntos
Glicopeptídeos/química , Iminoácidos/química , Nanoestruturas/química , Polímeros/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica de Varredura , Nanoestruturas/ultraestrutura , Porosidade , Propriedades de Superfície
11.
Electrophoresis ; 42(24): 2647-2655, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34687221

RESUMO

PDMS-based multichannel microfluidic chip was designed and fabricated in a simple approach using readily available tools. UV-initiated in situ polymerization of poly(2-hydroxy ethyl methacrylate-co-di(ethylene glycol) diacrylate-co-N,N'-diallyl l-tartardiamide) in an Eppendorf tube was achieved within 40 min. This polymerization process was successfully translated to a microfluidic chip format without any further modifications. Iminodiacetic acid was successfully immobilized on aldehyde functional monoliths via Schiff base reaction and confirmed by FT-IR spectroscopy. Four transition metal ions (Co (II), Zn (II), Ni (II), and Cu (II)) were chelated individually on four IDA-monolith microfluidic chips. The conjoint metal-ion monolith microfluidic chip has displayed high permeability (9.40 × 10-13  m2 ) and a porosity of 32.8%. This affinity microfluidic chip has pre-fractioned four human plasma proteins (fibrinogen, immunoglobulin, transferrin, and human serum albumin) based on their surface-exposed histidine surface topography. A protein recovery of approximately 95% (Bradford assay data) was achieved. The multimonolith microchip can be reusable even after three protein adsorption-desorption cycles.


Assuntos
Proteínas Sanguíneas , Iminoácidos , Microfluídica , Proteínas Sanguíneas/isolamento & purificação , Cátions , Humanos , Metais , Espectroscopia de Infravermelho com Transformada de Fourier
12.
ChemMedChem ; 16(20): 3231-3235, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34288492

RESUMO

Because some of the potentially most useful boronic acids are inherently unstable in blood plasma and exhibit poor selective retention in tumours, 2-heterocyclic N-methyliminodiacetic acid (MIDA) boronates provide a stable, spacious and highly effective harbor for prodrug conjugates. Herein we report MIDA boronates in conjunction with naphthalene-based fluorophores as suitable compounds for tumour diagnosis by virtue of their remarkable specificity and uniform benchtop stability. The shielding group was found to be effective at imparting stability under physiological conditions (pH 7.4), with rapid release of the drug upon exposure to the acidic microenvironment of the tumor. This approach significantly enhanced the efficiency of drug release and was found to exhibit fewer side effects, thus indicating its great potential for precision therapeutics.


Assuntos
Antineoplásicos/farmacologia , Compostos Heterocíclicos/farmacologia , Peróxido de Hidrogênio/química , Iminoácidos/farmacologia , Pró-Fármacos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Compostos Heterocíclicos/química , Humanos , Iminoácidos/química , Estrutura Molecular , Naftalenos/química , Naftalenos/farmacologia , Pró-Fármacos/síntese química , Pró-Fármacos/química , Relação Estrutura-Atividade
13.
Food Chem ; 361: 130061, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34023689

RESUMO

Two collagens were made from giant salamander (Andrias davidianus) skin by using acid and pepsin extraction methods. The yields of acid-soluble and pepsin-soluble collagens were 26.9 and 58.7%, respectively. The results of spectrum, electrophoresis and amino acid analysis showed that they were type 1 collagen with two α and one ß peptides and high imino acid content. They had low solubility at a pH above 6 or salt concentration over 5%. The pepsin-soluble collagen had a better emulsion activity index. The odorants in raw skin and collagens were identified and evaluated using gas-chromatography mass-spectrometer and olfactometry methods and sensory analysis. The fishy and fatty off-odors in skin were not perceivable in the collagens. Sour, ammonia-like, and acrid off-odors were found in the collagens due to acid and enzymatic hydrolysis and protein degradation. The off-odor intensity of pepsin-soluble collagen was low. It could be considered a good and safe collagen material.


Assuntos
Aminoácidos/análise , Colágeno Tipo I/química , Urodelos/metabolismo , Ácidos , Animais , Colágeno Tipo I/isolamento & purificação , Colágeno Tipo I/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Concentração de Íons de Hidrogênio , Hidrólise , Iminoácidos/análise , Odorantes/análise , Olfatometria , Pepsina A/metabolismo , Proteólise , Pele/metabolismo , Microextração em Fase Sólida , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier
14.
Environ Sci Pollut Res Int ; 28(28): 37322-37337, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33715124

RESUMO

A novel adsorbent (PN-Fe3O4-IDA-Zr) was developed from the chemical modification of peanut husk (a low cost material) with Fe3O4, iminodiacetic acid (IDA) and zirconium (Zr) and its efficacy for the sequestration of wastewater assessed using Alizarin red (AR) and Acid chrome blue K (AK) as model pollutants. To elucidate the characteristics of the formed adsorbent, analytical techniques such as the Bruauner-Emmet-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffractive spectroscopy (XRD) and vibrating sample magnetometer (VSM) were applied. Results from these studies confirmed the formation of a crystalline mesoporous adsorbent with surface properties which enhanced its usefulness. From the adsorption studies, it was observed that factors such as pH, salts, temperature and contact time influenced the uptake of the anionic dyes. The maximum monolayer capacity of PN-Fe3O4-IDA-Zr for AR was 49.4 mg g-1 (at 313 K) and was well fitted by the Langmuir model with the chemisorption process being the dominant reaction mechanism. In binary systems, PN-Fe3O4-IDA-Zr exhibited higher affinity for AR as compared with AK. The significant removal efficiency exhibited by this novel adsorbent as well as other unique features such as easy retrieval and high regeneration promotes its prospects as an adsorbent for practical wastewater remediation processes.


Assuntos
Corantes , Poluentes Químicos da Água , Adsorção , Arachis , Concentração de Íons de Hidrogênio , Iminoácidos , Cinética , Fenômenos Magnéticos , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise , Zircônio
15.
Methods Mol Biol ; 2280: 199-218, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33751437

RESUMO

This chapter describes a method to assay the activity of reactive intermediate deaminases (Rid), a large family of conserved soluble enzymes, which have been proposed to prevent damages from metabolic intermediates such as the highly reactive and unstable compounds enamines/imines. In this method, the flavin adenine dinucleotide-dependent L- or D-amino acid oxidases generate an imino acid starting from a L- or D- amino acid, respectively. This reaction is coupled to the hydrolysis of the imino acid to the corresponding α-keto acid and ammonium ion catalyzed by a Rid enzyme. The spectrophotometric assay consists of measuring the decrease of the initial rate of formation of the semicarbazone, derived from the spontaneous reaction of the imino acid and semicarbazide, caused by the presence of the Rid enzyme. The set-up and testing of this method imply a preliminary characterization of the ability of the amino acid oxidase to release the imino acid required for the subsequent reactions. To this purpose, the activity of the L- or D-amino acid oxidases with different amino acids can be measured as production of hydrogen peroxide or formation of semicarbazone in parallel assays. The advantages and limitations of this assay of Rid activity are discussed.


Assuntos
D-Aminoácido Oxidase/metabolismo , Iminoácidos/análise , L-Aminoácido Oxidase/metabolismo , Peróxido de Hidrogênio/análise , Hidrólise , Iminoácidos/metabolismo
16.
Amino Acids ; 53(3): 347-358, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33586043

RESUMO

L-amino acids (L-AAs) play different important roles in the physiology of all living organisms. Their chiral counterparts, D-amino acids (D-AAs) are increasingly being recognized as essential molecules in many biological systems. Secondary amino acids with cyclic structures, such as prolines, exhibit conformational rigidity and thus unique properties in the structural and protein folding. Despite their widespread occurrence, much less attention was paid to their chiral analysis, particularly when the minor, typically D-enantiomer, is present in low amounts in a complex biological matrix. In this paper, a cost-effective, chiral GC-MS method is described for capillary Chirasil-L-Val separation of nine cyclic secondary amino acid enantiomers with four-, five-, and six-membered rings, involving azetidine-2-carboxylic acid, pipecolic acid, nipecotic acid, proline, isomeric cis/trans 3-hydroxy, 4-hydroxyproline, and cis/trans-5-hydroxy-L-pipecolic acid in the excess of its enantiomeric antipode. The sample preparation involves in-situ derivatization with heptafluorobutyl chloroformate, simultaneous liquid-liquid micro-extraction into isooctane followed by amidation of the arising low-polar derivatives with methylamine, an evaporation step, re-dissolution, and final GC-MS analysis. The developed method was used for analyses of human biofluids, biologically active peptides containing chiral proline constituents, and collagen.


Assuntos
Fluorcarbonetos/química , Formiatos/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Iminoácidos/análise , Metilaminas/química , Calibragem , Cromatografia Gasosa-Espectrometria de Massas/normas , Humanos , Iminoácidos/química , Reprodutibilidade dos Testes , Estereoisomerismo
17.
Phys Chem Chem Phys ; 23(6): 3810-3819, 2021 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-33533341

RESUMO

Electron paramagnetic resonance (EPR) distance measurements are making increasingly important contributions to studies of biomolecules underpinning health and disease by providing highly accurate and precise geometric constraints. Combining double-histidine (dH) motifs with CuII spin labels shows promise for further increasing the precision of distance measurements, and for investigating subtle conformational changes. However, non-covalent coordination-based spin labelling is vulnerable to low binding affinity. Dissociation constants of dH motifs for CuII-nitrilotriacetic acid were previously investigated via relaxation induced dipolar modulation enhancement (RIDME), and demonstrated the feasibility of exploiting the dH motif for EPR applications at sub-µM protein concentrations. Herein, the feasibility of using modulation depth quantitation in CuII-CuII RIDME to simultaneously estimate a pair of non-identical independent KD values in such a tetra-histidine model protein is addressed. Furthermore, we develop a general speciation model to optimise CuII labelling efficiency, depending upon pairs of identical or disparate KD values and total CuII label concentration. We find the dissociation constant estimates are in excellent agreement with previously determined values, and empirical modulation depths support the proposed model.


Assuntos
Proteínas de Bactérias/química , Complexos de Coordenação/química , Cobre/química , Histidina/química , Marcadores de Spin , Quelantes/química , Espectroscopia de Ressonância de Spin Eletrônica , Iminoácidos/química , Modelos Químicos , Ácido Nitrilotriacético/química , Streptococcus/química
18.
Chem Biol Drug Des ; 97(1): 134-147, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32844569

RESUMO

Prodrugs are pharmacologically attenuated derivatives of drugs that undergo bioconversion into the active compound once reaching the targeted site, thereby maximizing their efficiency. This strategy has been implemented in pharmaceuticals to overcome obstacles related to absorption, distribution, and metabolism, as well as with intracellular dyes to ensure concentration within cells. In this study, we provide the first examples of a prodrug strategy that can be applied to simple phenolic antimicrobials to increase their potency against mature biofilms. The addition of (acetoxy)methyl iminodiacetate groups increases the otherwise modest potency of simple phenols. Biofilm-forming bacteria exhibit a heightened tolerance toward antimicrobial agents, thereby accentuating the need for new antibiotics as well as those, which incorporate novel delivery strategies to enhance activity toward biofilms.


Assuntos
Anti-Infecciosos/farmacologia , Biofilmes/efeitos dos fármacos , Iminoácidos/química , Fenóis/química , Pró-Fármacos/farmacologia , Anti-Infecciosos/química , Testes de Sensibilidade Microbiana , Fenóis/farmacologia , Pró-Fármacos/química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/fisiologia , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/fisiologia , Relação Estrutura-Atividade
19.
Environ Pollut ; 268(Pt A): 115729, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33011610

RESUMO

The presence of higher concentrations of heavy metals in water affects its quality with a concomitant adverse effect on its users thus their removal is paramount. A novel adsorbent, PN-Fe3O4-IDA derived from the chemical modification of peanut husk (a low-cost agricultural biomass produced in significant quantities globally) using magnetic nanoparticles (Fe3O4) and iminodiacetic acid was utilized for the remediation of heavy metals in aqueous solution. Analytical techniques vis-à-vis the Fourier-Transform Infrared, Scanning Electron Microscope, Brunauer-Emmett-Teller, X-ray photoelectron spectroscopy and X-ray Diffraction were applied for the characterization of PN-Fe3O4-IDA. Results from the characterization studies showed that PN-Fe3O4-IDA possessed a mesoporous structure, a heterogeneous surface and functional groups such as carboxylic acid and a tertiary nitrogen atom which enhanced its adsorption capacities as well as magnetic properties which ensured its easy removal from the solution using a magnet. The maximum uptake of Pb and Cu onto PN-Fe3O4-IDA was 0.36 and 0.75 mmol g-1 (at 318 K) respectively with the chemisorption process being the major reaction pathway for the processes. The synthesized adsorbent exhibits significant adsorption capacity for the selected pollutants as well as some unique features which promotes its use as an adsorbent for wastewater remediation processes.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Adsorção , Arachis , Concentração de Íons de Hidrogênio , Iminoácidos , Cinética , Chumbo , Água , Poluentes Químicos da Água/análise
20.
Clin Nucl Med ; 46(1): e8-e10, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33031234

RESUMO

A 68-year-old man with hereditary hypercoagulability was referred to nuclear medicine for elevated aminotransferases after a recent living-donor liver transplant. A hepatic infarction was suspected. A Tc-mebrofenin SPECT/CT was performed and showed decreased radiotracer uptake in a wedge-shaped distribution in the anterior liver suggestive of a hepatic infarction. Subsequently, an enhanced MRI corroborated the diagnosis. Oral anticoagulation therapy was then initiated, and aminotransferases soon normalized.


Assuntos
Infarto Hepático/diagnóstico por imagem , Iminoácidos , Compostos de Organotecnécio , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único , Idoso , Compostos de Anilina , Glicina , Infarto Hepático/tratamento farmacológico , Infarto Hepático/fisiopatologia , Humanos , Transplante de Fígado , Masculino
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