RESUMEN
Human Galectin-3 (hGal-3) is a protein that selectively binds to ß-galactosides and holds diverse roles in both normal and pathological circumstances. Therefore, targeting hGal-3 has become a vibrant area of research in the pharmaceutical chemistry. As a step towards the development of novel hGal-3 inhibitors, we synthesized and investigated derivatives of thiodigalactoside (TDG) modified with different aromatic substituents. Specifically, we describe a high-yielding synthetic route of thiodigalactoside (TDG); an optimized procedure for the synthesis of the novel 3,3'-di-O-(quinoline-2-yl)methyl)-TDG and three other known, symmetric 3,3'-di-O-TDG derivatives ((naphthalene-2yl)methyl, benzyl, (7-methoxy-2H-1-benzopyran-2-on-4-yl)methyl). In the present study, using competition Saturation Transfer Difference (STD) NMR spectroscopy, we determined the dissociation constant (Kd) of the former three TDG derivatives produced to characterize the strength of the interaction with the target protein (hGal-3). Based on the Kd values determined, the (naphthalen-2-yl)methyl, the (quinolin-2-yl)methyl and the benzyl derivatives bind to hGal-3 94, 30 and 24 times more strongly than TDG. Then, we studied the binding modes of the derivatives in silico by molecular docking calculations. Docking poses similar to the canonical binding modes of well-known hGal-3 inhibitors have been found. However, additional binding forces, cation-π interactions between the arginine residues in the binding pocket of the protein and the aromatic groups of the ligands, have been established as significant features. Our results offer a molecular-level understanding of the varying affinities observed among the synthesized thiodigalactoside derivatives, which can be a key aspect in the future development of more effective ligands of hGal-3.
Asunto(s)
Galectina 3 , Tiogalactósidos , Humanos , Galectina 3/antagonistas & inhibidores , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Simulación del Acoplamiento Molecular , Unión Proteica , Tiogalactósidos/química , Tiogalactósidos/farmacologíaRESUMEN
A simplified molecular-dynamics-based electronic circular dichroism (ECD) approach was tested on three condensed derivatives with limited conformational flexibility and an isochroman-2H-chromene hybrid, the ECD spectra of which could not be precisely reproduced by the conventional ECD calculation protocol. Application of explicit solvent molecules at the molecular mechanics (MD) level in the dynamics simulations and subsequent TDDFT-ECD calculation for the unoptimized MD structures was able to improve the agreements between experimental and computed spectra. Since enhancements were achieved even for molecules with limited conformational flexibility, deformations caused by the solvent molecules and multitudes of conformers produced with unoptimized geometries seem to be key factors for better agreement. The MD approach could confirm that aggregation of the phenanthrene natural product luzulin A had a significant contribution to a specific wavelength range of the experimental ECD. The MD approach has proved that dimer formation occurred in solution and this was responsible for the anomalous ECD spectrum. The scope and limitations of the method have also been discussed.
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Dicroismo Circular , Simulación de Dinámica Molecular , Dicroismo Circular/métodos , Fenantrenos/química , Conformación Molecular , Solventes/químicaRESUMEN
Human galectin-3 (hGal-3) is involved in a variety of biological processes and is implicated in wide range of diseases. As a result, targeting hGal-3 for clinical applications has become an intense area of research. As a step towards the development of novel hGal-3 inhibitors, we describe a study of the binding of two Se-containing hGal-3 inhibitors, specifically that of di(ß-D-galactopyranosyl)selenide (SeDG), in which two galactose rings are linked by one Se atom and a di(ß-D-galactopyranosyl)diselenide (DSeDG) analogue with a diseleno bond between the two sugar units. The binding affinities of these derivatives to hGal-3 were determined by 15N-1H HSQC NMR spectroscopy and fluorescence anisotropy titrations in solution, indicating a slight decrease in the strength of interaction for SeDG compared to thiodigalactoside (TDG), a well-known inhibitor of hGal-3, while DSeDG displayed a much weaker interaction strength. NMR and FA measurements showed that both seleno derivatives bind to the canonical S face site of hGal-3 and stack against the conserved W181 residue also confirmed by X-ray crystallography, revealing canonical properties of the interaction. The interaction with DSeDG revealed two distinct binding modes in the crystal structure which are in fast exchange on the NMR time scale in solution, explaining a weaker interaction with hGal-3 than SeDG. Using molecular dynamics simulations, we have found that energetic contributions to the binding enthalpies mainly differ in the electrostatic interactions and in polar solvation terms and are responsible for weaker binding of DSeDG compared to SeDG. Selenium-containing carbohydrate inhibitors of hGal-3 showing canonical binding modes offer the potential of becoming novel hydrolytically stable scaffolds for a new class of hGal-3 inhibitors.
Asunto(s)
Proteínas Sanguíneas/química , Galectina 3 , Galectinas/química , Cristalografía por Rayos X , Galactosa , Galectina 3/metabolismo , Galectinas/metabolismo , Humanos , Unión ProteicaRESUMEN
BACKGROUND: Pseudocysts being the most frequent local complications of acute pancreatitis (AP) have substantial effect on the disease course, hospitalization and quality of life of the patient. Our study aimed to understand the effects of pre-existing (OLD-P) and newly developed (NEW-P) pseudocysts on AP. METHODS: Data were extracted from the Acute Pancreatitis Registry organized by the Hungarian Pancreatic Study Group (HPSG). 2275 of 2461 patients had uploaded information concerning pancreatic morphology assessed by imaging technique. Patients were divided into "no pseudocyst" (NO-P) group, "old pseudocyst" (OLD-P) group, or "newly developed pseudocyst" (NEW-P) groups. RESULTS: The median time of new pseudocyst development was nine days from hospital admission and eleven days from the beginning of the abdominal pain. More NEW-P cases were severe (15.9% vs 4.7% in the NO-P group p < 0.001), with longer length of hospitalization (LoH) (median: 14 days versus 8 days, p < 0.001), and were associated with several changed laboratory parameters. OLD-P was associated with male gender (72.2% vs. 56.1%, p = 0.0014), alcoholic etiology (35.2% vs. 19.8% in the NO-P group), longer hospitalization (median: 10 days, p < 0.001), a previous episode of AP (p < 0.001), pre-existing diagnosis of chronic pancreatitis (CP) (p < 0.001), current smoking (p < 0.001), and increased alcohol consumption (unit/week) (p = 0.014). CONCLUSION: Most of the new pseudocysts develop within two weeks. Newly developing pseudocysts are associated with a more severe disease course and increased length of hospitalization. Pre-existing pseudocysts are associated with higher alcohol consumption and smoking. Because CP is more frequently associated with a pre-existing pseudocyst, these patients need closer attention after AP.
RESUMEN
Elucidation and improvement of the blood coagulant properties of heparin are the focus of intense research. In this study, we performed conformational analysis using nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) simulations on the heparin pentasaccharide analogue idraparinux, its disulfonatomethyl analogue, which features a slightly improved blood coagulation property, and a trisulfonatomethyl analogue, in which the activity has been totally abolished. As the ring conformation of the G subunit has been suggested as a major determinant of the biological properties, we analyzed the sugar ring conformations and dynamics of the interglycosidic linkages. We found that the conformation of the G ring is dominated by the 2SO skewed boat next to the 1C4 chair in all three derivatives. Both the thermodynamics and the kinetics of the conformational states were found to be highly similar in the three derivatives. Molecular kinetic analysis showed that the 2SO skewed boat state of the G ring is equally favorable in the three analogues, resulting in similar 2SO populations. Also, the transition kinetics from the 1C4 chair to the 2SO skewed boat was found to be comparable in the derivatives, which indicates a similar energy barrier between the two states of the G subunit. We also identified a slower conformational transition between the dominant 4C1 chair and the boat conformations on the E subunit. Both G and E ring flips are also accompanied by changes along the interglycosidic linkages, which take place highly synchronously with the ring flips. These findings indicate that conformational plasticity of the G ring and the dominance of the 2SO skewed boat populations do not necessarily warrant the biological activity of the derivatives and hence the impact of other factors also needs to be considered.
Asunto(s)
Heparina , Simulación de Dinámica Molecular , Cinética , Espectroscopía de Resonancia Magnética , OligosacáridosRESUMEN
BACKGROUND: Hypertriglyceridemia is the third most common cause of acute pancreatitis (AP). It has been shown that hypertriglyceridemia aggravates the severity and related complications of AP; however, detailed analyses of large cohorts are contradictory. Our aim was to investigate the dose-dependent effect of hypertriglyceridemia on AP. METHODS: AP patients over 18 years old who underwent triglyceride measurement within the initial three days were included into our cohort analysis from a prospective international, multicenter AP registry operated by the Hungarian Pancreatic Study Group. Data on 716 AP cases were analyzed. Six groups were created based on the highest triglyceride level (<1.7 mmol/l, 1.7-2.19 mmol/l, 2.2-5.59 mmol/l, 5.6-11.29 mmol/l, 11.3-22.59 mmol/l, ≥22.6 mmol/l). RESULTS: Hypertriglyceridemia (≥1.7 mmol/l) presented in 30.6% of the patients and was significantly and dose-dependently associated with younger age and male gender. In 7.7% of AP cases, hypertriglyceridemia was considered as a causative etiological factor (≥11.3 mmol/l); however, 43.6% of these cases were associated with other etiologies (alcohol and biliary). Hypertriglyceridemia was significantly and dose-dependently related to obesity and diabetes. The rates of local complications and organ failure and maximum CRP level were significantly and dose-dependently raised by hypertriglyceridemia. Triglyceride above 11.3 mmol/l was linked to a significantly higher incidence of moderately severe AP and longer hospital stay, whereas triglyceride over 22.6 mmol/l was significantly associated with severe AP as well. CONCLUSION: Hypertriglyceridemia dose-dependently aggravates the severity and related complications of AP. Diagnostic workup for hypertriglyceridemia requires better awareness regardless of the etiology of AP.
Asunto(s)
Hipertrigliceridemia/complicaciones , Pancreatitis/etiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Femenino , Humanos , Internacionalidad , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo , Adulto JovenRESUMEN
We report the enhancement of the lipopolysaccharide-induced immune response by adamantane containing peptidoglycan fragments in vitro. The immune stimulation was detected by Il-6 (interleukine 6) and RANTES (regulated on activation, normal T cell expressed and secreted) chemokine expression using cell assays on immortalized mouse bone-marrow derived macrophages. The most active compound was a α-D-mannosyl derivative of an adamantylated tripeptide with L-chirality at the adamantyl group attachment, whereby the mannose moiety assumed to target mannose receptors expressed on macrophage cell surfaces. The immune co-stimulatory effect was also influenced by the configuration of the adamantyl center, revealing the importance of specific molecular recognition event taking place with its receptor. The immunostimulating activities of these compounds were further enhanced upon their incorporation into lipid bilayers, which is likely related to the presence of the adamantyl group that helps anchor the peptidoglycan fragment into lipid nanoparticles. We concluded that the proposed adamantane containing peptidoglycan fragments act as co-stimulatory agents and are also suitable for the preparation of lipid nanoparticle-based delivery of peptidoglycan fragments.
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Adamantano/química , Quimiocina CCL5/metabolismo , Interleucina-6/metabolismo , Lipopolisacáridos/farmacología , Macrófagos/metabolismo , Peptidoglicano/farmacología , Animales , Células Cultivadas , Macrófagos/efectos de los fármacos , Macrófagos/inmunología , Ratones , Ratones Endogámicos C57BL , Peptidoglicano/químicaRESUMEN
Proline is often found as a turn inducer in peptide or protein domains. Exploitation of its restricted conformational freedom led to the development of the d-Pro-l-Pro (corresponding to (R)-Pro-(S)-Pro) segment as a "templating" unit, frequently used in the design of ß-hairpin peptidomimetics, in which conformational stability is, however, inherently linked to the cis-trans isomerization of the prolyl amide bonds. In this context, the stereoelectronic properties of the CF3 group can aid in conformational control. Herein, the impact of α-trifluoromethylated proline analogues is examined for the design of enhanced ß-turn inducers. A theoretical conformational study permitted the dipeptide (R)-Pro-(R)-TfmOxa (TfmOxa: 2-trifluoromethyloxazolidine-2-carboxylic acid) to be selected as a template with an increased trans-cis rotational energy barrier. NMR spectroscopic analysis of the Ac-(R)-Pro-(R)-TfmOxa-(S)-Val-OtBu ß-turn model, obtained through an original synthetic pathway, validated the prevalence of a major trans-trans conformer and indicated the presence of an internal hydrogen bond. Altogether, it was shown that the (R)-Pro-(R)-TfmOxa template fulfilled all crucial ß-turn-inducer criteria.
Asunto(s)
Ácidos Carboxílicos/química , Dipéptidos/química , Oxazolona/análogos & derivados , Prolina/análogos & derivados , Enlace de Hidrógeno , Espectroscopía de Resonancia Magnética , Metilación , Oxazolona/química , Conformación Proteica , TermodinámicaRESUMEN
Computational description of conformational and dynamic properties of anticoagulant heparin analogue pentasaccharides is of crucial importance in understanding their biological activities. We designed and synthesized idraparinux derivatives modified with sulfonatomethyl moieties at the D, F, and H glucose units that display varied potencies depending on the exact nature of the substitution. In this report we examined the capability of molecular dynamics (MD) simulations to describe the conformational behavior of these novel idraparinux derivatives. We used Gaussian accelerated MD (GAMD) simulations on the parent compound, idraparinux, to choose the most suitable carbohydrate force field for these type of compounds. GAMD provided significant acceleration of conformational transitions compared to classical MD. We compared descriptors obtained from GAMD with NMR spectroscopic parameters related to geometrical descriptors such as scalar couplings and nuclear Overhauser effects (NOE) measured on idraparinux. We found that the experimental data of idraparinux is best reproduced by the CHARMM carbohydrate force field. Furthermore, we propose a torsion angle parameter for the sulfonato-methyl group, which was developed for the chosen CHARMM force field using quantum chemical calculations and validated by comparison with NMR data. The work lays down the foundation of using MD simulations to gain insight into the conformational properties of sulfonato-methyl group modified idraparinux derivatives and to understand their structure-activity relationship thus enabling rational design of further modifications.
Asunto(s)
Inhibidores del Factor Xa/química , Heparina/análogos & derivados , Simulación de Dinámica Molecular , Oligosacáridos/química , Diseño de Fármacos , Glucosa/análogos & derivados , Metilación , Distribución NormalRESUMEN
Many Pseudomonas spp. produce cyclic lipodepsipeptides (CLPs), which, besides their role in biological functions such as motility, biofilm formation and interspecies interactions, are antimicrobial. It has been established that interaction with the cellular membrane is central to the mode of action of CLPs. In this work, we focus on the CLPs of the so-called viscosin group, aiming to assess the impact of the main structural variations observed within this group on both the antimicrobial activity and the interaction with model membranes. The antimicrobial activity of viscosin, viscosinamide A, WLIP and pseudodesmin A were all tested on a broad panel of mainly Gram-positive bacteria. Their capacity to permeabilize or fuse PG/PE/cardiolipin model membrane vesicles is assessed using fluorescent probes. We find that the Glu2/Gln2 structural variation within the viscosin group is the main factor that influences both the membrane permeabilization properties and the minimum inhibitory concentration of bacterial growth, while the configuration of the Leu5 residue has no apparent effect. The CLP-membrane interactions were further evaluated using CD and FT-IR spectroscopy on model membranes consisting of PG/PE/cardiolipin or POPC with or without cholesterol. In contrast to previous studies, we observe no conformational change upon membrane insertion. The CLPs interact both with the polar heads and aliphatic tails of model membrane systems, altering bilayer fluidity, while cholesterol reduces CLP insertion depth.
Asunto(s)
Membrana Dobles de Lípidos/química , Lipopéptidos/química , Péptidos Cíclicos/química , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Dicroismo Circular , Bacterias Gramnegativas/efectos de los fármacos , Bacterias Grampositivas/efectos de los fármacos , Membrana Dobles de Lípidos/metabolismo , Lipopéptidos/metabolismo , Lipopéptidos/farmacología , Espectroscopía de Resonancia Magnética , Pruebas de Sensibilidad Microbiana , Péptidos Cíclicos/metabolismo , Péptidos Cíclicos/farmacología , Permeabilidad/efectos de los fármacos , Pseudomonas/metabolismo , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
G protein-coupled receptors (GPCRs) play an important role in many cellular responses; as such, their mechanism of action is of utmost interest. To gain insight into the active conformation of GPCRs, the X-ray crystal structures of nanobody (Nb)-stabilized ß2 -adrenergic receptor (ß2 AR) have been reported. Nb80, in particular, is able to bind the intracellular G protein binding site of ß2 AR and stabilize the receptor in an active conformation. Within Nb80, the complementarity-determining region 3 (CDR3) is responsible for most of the binding interactions. Hence, we hypothesized that peptidomimetics of the CDR3 loop might be sufficient for binding to the receptor, inhibiting the interaction of ß2 AR with intracellular GPCR interacting proteins (e.g., G proteins). Based on previous crystallographic data, a set of peptidomimetics were synthesized that, similar to the Nb80 CDR3 loop, adopt a ß-hairpin conformation. Syntheses, conformational analysis, binding and functional in vitro assays, as well as internalization experiments, were performed. We demonstrate that peptidomimetics can structurally mimic the CDR3 loop of a nanobody and its function by inhibiting G protein coupling as measured by partial inhibition of cAMP production.
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Peptidomiméticos/síntesis química , Receptores Adrenérgicos beta 2/metabolismo , Anticuerpos de Dominio Único/química , Sitios de Unión , Simulación por Computador , Diseño de Fármacos , Células HEK293 , Células HeLa , Humanos , Ligandos , Imagen Óptica , Peptidomiméticos/química , Unión Proteica , Conformación Proteica , Receptores Adrenérgicos beta 2/químicaRESUMEN
The emerging significance of recognition of cellular glycans by lectins for diverse aspects of pathophysiology is a strong incentive for considering development of bioactive and non-hydrolyzable glycoside derivatives, for example by introducing S/Se atoms and the disulfide group instead of oxygen into the glycosidic linkage. We report the synthesis of 12 bivalent thio-, disulfido- and selenoglycosides attached to benzene/naphthalene cores. They present galactose, for blocking a plant toxin, or lactose, the canonical ligand of adhesion/growth-regulatory galectins. Modeling reveals unrestrained flexibility and inter-headgroup distances too small to bridge two sites in the same lectin. Inhibitory activity was first detected by solid-phase assays using a surface-presented glycoprotein, with relative activity enhancements per sugar unit relative to free cognate sugar up to nearly 10fold. Inhibitory activity was also seen on lectin binding to surfaces of human carcinoma cells. In order to proceed to characterize this capacity in the tissue context monitoring of lectin binding in the presence of inhibitors was extended to sections of three types of murine organs as models. This procedure proved to be well-suited to determine relative activity levels of the glycocompounds to block binding of the toxin and different human galectins to natural glycoconjugates at different sites in sections. The results on most effective inhibition by two naphthalene-based disulfides and a selenide raise the perspective for broad applicability of the histochemical assay in testing glycoclusters that target biomedically relevant lectins.
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Glicósidos/química , Glicósidos/farmacología , Lectinas/antagonistas & inhibidores , Animales , Derivados del Benceno/química , Derivados del Benceno/farmacología , Línea Celular Tumoral , Disulfuros/química , Disulfuros/farmacología , Humanos , Lectinas/análisis , Ratones Endogámicos C57BL , Modelos Moleculares , Naftalenos/química , Naftalenos/farmacología , Compuestos de Organoselenio/química , Compuestos de Organoselenio/farmacologíaRESUMEN
The predictable 3D structure of double-stranded DNA renders it ideally suited as a template for the bottom-up design of functionalized nucleic acid-based active sites. We here explore the use of a 14mer DNA duplex as a scaffold for the precise and predictable positioning of catalytic functionalities. Given the ubiquitous participation of the histidine-based imidazole group in protein recognition and catalysis events, single histidine-like modified duplexes were investigated. Tethering histamine to the C5 of the thymine base via an amide bond, allows the flexible positioning of the imidazole function in the major groove. The mutual interactions between the imidazole and the duplex and its influence on the imidazolium pKaH are investigated by placing a single modified thymine at four different positions in the center of the 14mer double helix. Using NMR and unrestrained molecular dynamics, a structural motif involving the formation of a hydrogen bond between the imidazole and the Hoogsteen side of the guanine bases of two neighboring GC base pairs is established. The motif contributes to a stabilization against thermal melting of 6°C and is key in modulating the pKaH of the imidazolium group. The general features, prerequisites and generic character of the new pKaH-regulating motif are described.
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ADN/química , Imidazoles/química , Disparidad de Par Base , Secuencia de Bases , Enlace de Hidrógeno , Simulación de Dinámica Molecular , Conformación de Ácido Nucleico , Motivos de Nucleótidos , Timina/químicaRESUMEN
Biocompatible inorganic nano- and microcarriers can be suitable candidates for protein delivery. This study demonstrates facile methods of functionalization by using nanoscale linker molecules to change the protein adsorption capacity of hydroxyapatite (HA) powder. The adsorption capacity of bovine serum albumin as a model protein has been studied with respect to the surface modifications. The selected linker molecules (lysine, arginine, and phosphoserine) can influence the adsorption capacity by changing the electrostatic nature of the HA surface. Qualitative and quantitative analyses of linker-molecule interactions with the HA surface have been performed by using NMR spectroscopy, zeta-potential measurements, X-ray photoelectron spectroscopy, and thermogravimetric analyses. Additionally, correlations to theoretical isotherm models have been calculated with respect to Langmuir and Freundlich isotherms. Lysine and arginine increased the protein adsorption, whereas phosphoserine reduced the protein adsorption. The results show that the adsorption capacity can be controlled with different functionalization, depending on the protein-carrier selections under consideration. The scientific knowledge acquired from this study can be applied in various biotechnological applications that involve biomolecule-inorganic material interfaces.
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Arginina/química , Durapatita/química , Lisina/química , Nanopartículas/química , Fosfoserina/química , Adsorción , Animales , Arginina/metabolismo , Bovinos , Durapatita/metabolismo , Lisina/metabolismo , Fosfoserina/metabolismo , Espectroscopía de Fotoelectrones , Propiedades de SuperficieRESUMEN
Complex tumor therapy development and new opportunities in surgery, which take into account both oncological principles as well as esthetic aspects, have set the requirements far higher for diagnostic imaging of the breast and for radiologists. Despite these new opportunities, X-ray mammography remains the basic examination. However, part of the cancers is hidden on the mammogram, which is partly a consequence of the dense glandular tissue and may also be influenced by the histological type of cancer. Besides reducing radiation dose, digital X-ray mammography improves the examination sensitivity of the dense breast. State of the art digital examination methods, such as tomosynthesis and contrast-enhanced mammography, increase the accuracy of examination. Ultrasound mammography is the most important supplementary method of X-ray mammography. Among the new applications of ultrasound mammography, US elastography, which is based on different tissue elasticity, as well as automatic 3D ultrasound, can be highlighted. Furthermore, among imaging methods that provide functional or metabolic data, MR mammography is the most appropriate non-invasive, non-ionising method for the detection of malignancy and for structure examination. MR mammography is the most sensitive method for the detection of breast cancer and in 20-30% of cases, results in changes of the therapy, and it is also effective in the examination of the dense breast. High level of evidence proves that MR mammography is very useful in the screening of women at risk of breast cancer. Promising results prove that MR mammography will play more considerable role in the evaluation of the effectiveness of the therapy. Diffusion-weighted MR imaging is based on the different diffusion of tissue water, qualitative analysis and quantitative evaluation can be performed. DCE-MR examines that contrast enhancement over time, which can mainly be useful for the qualitative and quantitative evaluation of perfusion changes which may indicate the biological response to tumor therapy. The MR spectroscopic (MRSI) biochemical analysis increases the characterization of the lesions. Multimodal imaging techniques provide more accurate analysis, which is confirmed by more and more evidence, but none of the imaging methods are sufficiently specific to provide histological diagnosis. However, imaging-guided biopsies enable precise histological or cytological confirmation. Technical development, new imaging methods, experienced radiologists and multi-disciplinary cooperation increase the accuracy of the diagnosis and the effectiveness of personalized therapy.
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Neoplasias de la Mama/diagnóstico , Diagnóstico por Imagen de Elasticidad , Imagen por Resonancia Magnética , Mamografía , Ultrasonografía Mamaria , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/patología , Carcinoma Ductal de Mama/diagnóstico , Carcinoma Intraductal no Infiltrante/diagnóstico , Medios de Contraste , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Imagen por Resonancia Magnética/métodos , Imagen por Resonancia Magnética/tendencias , Mamografía/métodos , Mamografía/tendencias , Sensibilidad y Especificidad , Ultrasonografía Mamaria/métodos , Ultrasonografía Mamaria/tendenciasRESUMEN
The viscosin group covers a series of cyclic lipodepsipeptides (CLPs) produced by Pseudomonas bacteria, with a range of biological functions and antimicrobial activities. Their oligopeptide moieties are composed of both L- and D-amino acids. Remarkably, the Leu5 amino acid-centrally located in the nonapeptide sequence-is the sole residue found to possess either an L or D configuration, depending on the producing strain. The impact of this D/L switch on the solution conformation was investigated by NMR-restrained molecular modelling of the epimers pseudodesmin A and viscosinamide A. Although the backbone fold remained unaffected, the D/L switch adjusted the segregation between hydrophobic and hydrophilic residues, and thus the amphipathicity. It also influenced the self-assembly capacity in organic solvents. Additionally, several new minor variants of viscosinamide A from Pseudomonas fluorescens DR54 were identified, and an NMR assay is proposed to assess the presence of either an L- or D-Leu5.
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Péptidos Cíclicos/química , Pseudomonas fluorescens/química , Modelos Moleculares , Resonancia Magnética Nuclear Biomolecular , EstereoisomerismoRESUMEN
BACKGROUND: Increased lipase level is a serological hallmark of the diagnosis of acute pancreatitis (AP) but can be detected in various other diseases associated with lipase leakage due to inflammation of organs surrounding the pancreas or reduced renal clearance and/or hepatic metabolism. This non-pancreatic hyperlipasemia (NPHL) is puzzling for attending physicians during the diagnostic procedure for AP. It would be clinically beneficial to identify the clinical and laboratory variables that hinder the accuracy of lipase diagnosis with the aim of improve it. A more precise description of the NPHL condition could potentially provide prognostic factors for adverse outcomes which is currently lacking. AIM: To perform a detailed clinical and laboratory characterization of NPHL in a large prospective patient cohort with an assessment of parameters determining disease outcomes. METHODS: A Hungarian patient cohort with serum lipase levels at least three times higher than the upper limit of normal (ULN) was prospectively evaluated over 31 months. Patients were identified using daily electronic laboratory reports developed to support an ongoing observational, multicenter, prospective cohort study called the EASY trial (ISRCTN10525246) to establish a simple, easy, and accurate clinical scoring system for early prognostication of AP. Diagnosis of NPHL was established based on ≥ 3 × ULN serum lipase level in the absence of abdominal pain or abdominal imaging results characteristic of pancreatitis. RESULTS: A total of 808 patients [male, n = 420 (52%); median age (IQR): 65 (51-75) years] were diagnosed with ≥ 3 × ULN serum lipase levels. A total of 392 patients had AP, whereas 401 had NPHL with more than 20 different etiologies. Sepsis and acute kidney injury (AKI) were the most prevalent etiologies of NPHL (27.7% and 33.2%, respectively). The best discriminative cut-off value for lipase was ≥ 666 U/L (sensitivity, 71.4%; specificity, 88.8%). The presence of AKI or sepsis negatively affected the diagnostic performance of lipase. NPHL was associated with a higher in-hospital mortality than AP (22.4% vs 5.1%, P < 0.001). In multivariate binary logistic regression, not lipase but increased amylase level (> 244 U/L) and neutrophil-to-lymphocyte ratio (NLR) (> 10.37, OR: 3.71, 95%CI: 2.006-6.863, P < 0.001), decreased albumin level, age, and presence of sepsis were independent risk factors for in-hospital mortality in NPHL. CONCLUSION: NPHL is a common cause of lipase elevation and is associated with high mortality rates. Increased NLR value was associated with the highest mortality risk. The presence of sepsis/AKI significantly deteriorates the serological differentiation of AP from NPHL.
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Lipasa , Pancreatitis , Humanos , Lipasa/sangre , Masculino , Femenino , Persona de Mediana Edad , Estudios Prospectivos , Pancreatitis/sangre , Pancreatitis/diagnóstico , Anciano , Pronóstico , Hungría/epidemiología , Biomarcadores/sangre , AdultoRESUMEN
Aromatic oligovalent glycosyl disulfides and some diglycosyl disulfides were tested against three different Trypanosoma cruzi strains. Di-(ß-D-galactopyranosyl-dithiomethylene) benzenes 2b and 4b proved to be the most active derivatives against all three strains of cell culture-derived trypomastigotes with IC50 values ranging from 4 to 11 µM at 37 °C. The inhibitory activities were maintained, although somewhat lowered, at a temperature of 4 °C as well. Three further derivatives displayed similar activities against at least one of the three strains. Low cytotoxicities of the active compounds, tested on confluent HeLa, Vero and peritoneal macrophage cell cultures, resulted in significantly higher selectivity indices (SI) than that of the reference drug benznidazole. Remarkably, several molecules of the tested panel strongly inhibited the parasite release from T. cruzi infected HeLa cell cultures suggesting an effect against the intracellular development of T. cruzi amastigotes as well.
Asunto(s)
Antiprotozoarios/farmacología , Disulfuros/farmacología , Glicósidos/farmacología , Trypanosoma cruzi/efectos de los fármacos , Animales , Derivados del Benceno/farmacología , Enfermedad de Chagas/tratamiento farmacológico , Chlorocebus aethiops , Disulfuros/química , Glicósidos/química , Células HeLa , Humanos , Trypanosoma cruzi/crecimiento & desarrollo , Células VeroRESUMEN
During muscle cell differentiation, the alternatively spliced, acidic ß-domain potentiates transcription of Myocyte-specific Enhancer Factor 2 (Mef2D). Sequence analysis by the FuzDrop method indicates that the ß-domain can serve as an interaction element for Mef2D higher-order assembly. In accord, we observed Mef2D mobile nuclear condensates in C2C12 cells, similar to those formed through liquid-liquid phase separation. In addition, we found Mef2D solid-like aggregates in the cytosol, the presence of which correlated with higher transcriptional activity. In parallel, we observed a progress in the early phase of myotube development, and higher MyoD and desmin expression. In accord with our predictions, the formation of aggregates was promoted by rigid ß-domain variants, as well as by a disordered ß-domain variant, capable of switching between liquid-like and solid-like higher-order states. Along these lines, NMR and molecular dynamics simulations corroborated that the ß-domain can sample both ordered and disordered interactions leading to compact and extended conformations. These results suggest that ß-domain fine-tunes Mef2D higher-order assembly to the cellular context, which provides a platform for myogenic regulatory factors and the transcriptional apparatus during the developmental process.
Asunto(s)
Desarrollo de Músculos , Factores de Transcripción MEF2/genética , Diferenciación Celular , ExonesRESUMEN
Early diagnosis and prevention have the most significant effect on overall disease specific outcome; 90% of all breast cancer cases could be cured if diagnosed early and treated accurately. As for all diagnostic methods the most important requirement for diagnostic imaging is to detect breast cancer in its early stage, and to determine accurate tumor staging, in order to select the appropriate therapy. Its role is to monitor the effectiveness of therapy, to follow up patients reliably for early detection of recurrent disease. The spectrum of radiological imaging methods in breast cancer became broader in the past two decades; imaging that provides functional or metabolic data and whole body information such as CT, MRI and PET-CT are now available besides common X-ray and ultrasound mammography. The MRI is getting more and more important for the detection and characterization of breast cancer. Multimodal imaging techniques provide more accurate analysis, which is confirmed by increasing statistics authentically, but none of the imaging methods was specific enough to provide histological diagnosis. However, imaging-guided biopsies enable precise histological or cytological confirmation.