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1.
Entropy (Basel) ; 24(10)2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37420436

RESUMO

The aim of this paper is to study the quantum-like approach to the description of the market in the context of the principle of minimum Fisher information. We wish to investigate the validity of using squeezed coherent states as market strategies. For this purpose, we focus on the representation of any squeezed coherent state with respect to the basis of the eigenvectors of the observable of market risk. We derive a formula for the probability of being the squeezed coherent state in one of these states. The distribution that we call generalized Poisson establishes the relation between the squeezed coherent states and their description in the language of risk in quantum terms. We provide a formula specifying the total risk of squeezed coherent strategy. Then, we propose a risk of risk concept that is in fact the second central moment of the generalized Poisson distribution. This is an important numerical characterization of squeezed coherent strategies. We provide its interpretations on the basis of the uncertainty relation for time and energy.

2.
Heart Fail Rev ; 26(1): 111-125, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-31867681

RESUMO

This review presents a detailed study of original researches and previously published reviews concerning cardiovascular involvement in idiopathic inflammatory myopathies (IIM). We aimed to summarize the current knowledge on the cardiac involvement in IIM, evaluate its impact on mortality and indicate areas still awaiting to be investigated. We searched MEDLINE database (until January 2019) and the reference lists of articles. Selection criteria included only published data, available in English, both original researches and reviews. Articles related to cardiovascular involvement in IIM were selected and analysed. The references were also screened, and relevant articles were included. Cardiovascular involvement is frequent in IIM but typically remains subclinical. Among far less prevalent symptomatic forms, congestive heart failure is the most common. Myocardium and conduction system seems to be predominantly affected. High rate of left ventricular diastolic dysfunction was observed. Non-specific changes of ST-T segment were the most common abnormalities in electrocardiography. Patients with IIM were more frequently affected by atrial fibrillation as compared with other autoimmune diseases. Increased risk of myocardial infarction was observed; furthermore, patients often develop comorbidities that enhance cardiovascular risk. Since cardiovascular disorders remain one of the major causes of death and subclinical involvement is frequent, active screening is justified. Growing availability of the novel imaging techniques may facilitate diagnosis. Correlation between myocardial involvement and the type of autoantibodies and impact of different therapeutic options on the progression of cardiovascular lesions require further studies.


Assuntos
Doenças Autoimunes , Cardiopatias , Miosite , Disfunção Ventricular Esquerda , Coração , Humanos , Miosite/complicações , Miosite/epidemiologia
3.
Arch Biochem Biophys ; 704: 108858, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-33798534

RESUMO

Success rates in drug discovery are extremely low, and the imbalance between new drugs entering clinical research and their approval is steadily widening. Among the causes of the failure of new therapeutic agents are the lack of safety and insufficient efficacy. On the other hand, timely disease diagnosis may enable an early management of the disease, generally leading to better and less costly outcomes. Several strategies have been explored to overcome the barriers for drug development and facilitate diagnosis. Using lipid membranes as platforms for drug delivery or as biosensors are promising strategies, due to their biocompatibility and unique physicochemical properties. We examine some of the lipid membrane-based strategies for drug delivery and diagnostics, including their advantages and shortcomings. Regarding synthetic lipid membrane-based strategies for drug delivery, liposomes are the archetypic example of a successful approach, already with a long period of well-succeeded clinical application. The use of lipid membrane-based structures from biological sources as drug carriers, currently under clinical evaluation, is also discussed. These biomimetic strategies can enhance the in vivo lifetime of drug and delivery system by avoiding fast clearance, consequently increasing their therapeutic window. The strategies under development using lipid membranes for diagnostic purposes are also reviewed.


Assuntos
Materiais Biomiméticos , Técnicas Biossensoriais , Lipídeos de Membrana , Materiais Biomiméticos/química , Materiais Biomiméticos/uso terapêutico , Humanos , Lipossomos , Lipídeos de Membrana/química , Lipídeos de Membrana/metabolismo , Lipídeos de Membrana/uso terapêutico
4.
Soft Matter ; 17(23): 5806-5814, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34032258

RESUMO

The mechanical properties of a disordered heterogeneous medium depend, in general, on a complex interplay between multiple length scales. Connecting local interactions to macroscopic observables, such as stiffness or fracture, is thus challenging in this type of material. Here, we study the properties of a cohesive granular material composed of glass beads held together by soft polymer bridges. We characterise the mechanical response of single bridges under traction and shear, using a setup based on the deflection of flexible micropipettes. These measurements, along with information from X-ray microtomograms of the granular packings, then inform large-scale discrete element model (DEM) simulations. Although simple, these simulations are constrained in every way by empirical measurement and accurately predict mechanical responses of the aggregates, including details on their compressive failure, and how the material's stiffness depends on the stiffness and geometry of its parts. By demonstrating how to accurately relate microscopic information to macroscopic properties, these results provide new perspectives for predicting the behaviour of complex disordered materials, such as porous rock, snow, or foam.

5.
Entropy (Basel) ; 23(11)2021 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-34828162

RESUMO

The principle of minimum Fisher information states that in the set of acceptable probability distributions characterizing the given system, it is best done by the one that minimizes the corresponding Fisher information. This principle can be applied to transaction processes, the dynamics of which can be interpreted as the market tendency to minimize the information revealed about itself. More information involves higher costs (information is physical). The starting point for our considerations is a description of the market derived from the assumption of minimum Fisher information for a strategy with a fixed financial risk. Strategies of this type that minimize Fisher information overlap with the well-known eigenstates of a the quantum harmonic oscillator. The analytical extension of this field of strategy to the complex vector space (traditional for quantum mechanics) suggests the study of the interference of the oscillator eigenstates in terms of their minimization of Fisher information. It is revealed that the minimum value of Fisher information of the superposition of the two strategies being the ground state and the second excited state of the oscillator, has Fisher information less than the ground state of the oscillator. Similarly, less information is obtained for the system of strategies (the oscillator eigenstates) randomized by the Gibbs distribution. We distinguish two different views on the description of Fisher information. One of them, the classical, is based on the value of Fisher information. The second, we call it transactional, expresses Fisher information from the perspective of the constant risk of market strategies. The orders of the market strategies derived from these two descriptions are different. From a market standpoint, minimizing Fisher information is equivalent to minimizing risk.

6.
Rheumatol Int ; 40(7): 1133-1141, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32222805

RESUMO

Idiopathic inflammatory myopathies (IIM) are rare connective tissue diseases, which can lead to internal organ involvement. IL-33/ST2 pathway is involved in the pathogenesis of numerous diseases including autoimmune disorders. IL-33 fulfils cardioprotective function, while soluble ST2 (sST2) is a decoy receptor that reduces protective impact of IL-33. The aim of the study was to evaluate the concentrations of sST2 and IL-33 in sera of patients with IIM and evaluate its associations with the clinical course of the disease. Patients with IIM as well as age- and sex-matched healthy controls were recruited. Concentrations of sST2 and IL-33 were assessed with ELISA in sera of both patients and controls. Patients were asked to fill in the questionnaires concerning clinical symptoms and physical functioning. Concentrations of sST2 and IL-33 were correlated with the results of laboratory tests and clinical symptoms. Concentrations of sST2 were significantly higher in IIM group than in healthy subjects (median sST2 in IIM 26.51 vs in healthy controls 21.39; p = 0.03). In the majority of patients, IL-33 concentrations did not exceed the detection limit. Anti-SRP-positive patients presented significantly higher concentrations of sST2 as compared to anti-SRP-negative patients (p = 0.04). In patients with anti-Ro52 antibodies, sST2 concentrations were significantly lower than in anti-Ro52-negative patients (p = 0.02). Concentrations of sST2 correlated with the degree of disability evaluated with Health Assessment Questionnaire. sST2 is increased in patients with IIM and its concentration correlates with the degree of disability. In patients with anti-SRP antibodies, levels of sST2 are exceptionally high.


Assuntos
Proteína 1 Semelhante a Receptor de Interleucina-1/sangue , Interleucina-33/sangue , Miosite/sangue , Adulto , Idoso , Anticorpos Antinucleares/imunologia , Arritmias Cardíacas/fisiopatologia , Artralgia/fisiopatologia , Autoanticorpos/imunologia , Estudos de Casos e Controles , Dispneia/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mialgia/fisiopatologia , Miosite/imunologia , Miosite/fisiopatologia , Medição da Dor , Projetos Piloto , Ribonucleoproteínas/imunologia , Índice de Gravidade de Doença , Partícula de Reconhecimento de Sinal/imunologia , Transdução de Sinais
7.
Int J Mol Sci ; 21(23)2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-33265989

RESUMO

Discovering antibiotic molecules able to hold the growing spread of antimicrobial resistance is one of the most urgent endeavors that public health must tackle. The case of Gram-negative bacterial pathogens is of special concern, as they are intrinsically resistant to many antibiotics, due to an outer membrane that constitutes an effective permeability barrier. Antimicrobial peptides (AMPs) have been pointed out as potential alternatives to conventional antibiotics, as their main mechanism of action is membrane disruption, arguably less prone to elicit resistance in pathogens. Here, we investigate the in vitro activity and selectivity of EcDBS1R4, a bioinspired AMP. To this purpose, we have used bacterial cells and model membrane systems mimicking both the inner and the outer membranes of Escherichia coli, and a variety of optical spectroscopic methodologies. EcDBS1R4 is effective against the Gram-negative E. coli, ineffective against the Gram-positive Staphylococcus aureus and noncytotoxic for human cells. EcDBS1R4 does not form stable pores in E. coli, as the peptide does not dissipate its membrane potential, suggesting an unusual mechanism of action. Interestingly, EcDBS1R4 promotes a hemi-fusion of vesicles mimicking the inner membrane of E. coli. This fusogenic ability of EcDBS1R4 requires the presence of phospholipids with a negative curvature and a negative charge. This finding suggests that EcDBS1R4 promotes a large lipid spatial reorganization able to reshape membrane curvature, with interesting biological implications herein discussed.


Assuntos
Escherichia coli/efeitos dos fármacos , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Animais , Ânions , Morte Celular/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Humanos , Cinética , Fusão de Membrana/efeitos dos fármacos , Potenciais da Membrana/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Proteínas Citotóxicas Formadoras de Poros/química , Conformação Proteica
8.
Int J Mol Sci ; 20(21)2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31690061

RESUMO

The below article presents the results of spectroscopic research, theoretical (time-dependent density functional theory (TD-DFT)), microbiological, and antioxidative calculations for three compounds from the group of 1,3,4-thiadiazoles: 2-amino-5-phenyl-1,3,4-thiadiazole (TB), 2-amino-5-(2-hydroxyphenyl)-1,3,4-thiadiazole (TS), 2-amino-5-(2-hydroxy-5-sulfobenzoyl)-1,3,4-thiadiazole (TSF). In the fluorescence emission spectra (TS) of solutions with varying concentrations of hydrogen ions, a particularly interesting effect of dual fluorescence was observed. The aforementioned effect was observed even more clearly in the environment of butan-1-ol, relative to the compound's concentration. Depending on the modification of the resorcylic substituent (TS and TSF), we observed the emergence of two separate, partially overlapping, fluorescence emission spectra or a single emission spectrum. Interpretation of the obtained spectra using stationary and time-resolved spectroscopy allowed the correlation of the effect's emergence with the phenomenon of molecular aggregation (of a particular type) as well as, above all, the structure of the substituent system. The overlap of said effects most likely induces the processes related to the phenomenon of charge transfer (in TS) and is responsible for the observed fluorescence effects. Also, the position of the -OH group (in the resorcylic ring) is significant and can facilitate the charge transfer (CT). The determinations of the changes in the dipole moment and TD-DFT calculations further corroborate the above assumption. The following paper presents the analysis (the first for this particular group of analogues) of the fluorescence effects relative to the changes in the structure of the resorcylic group combined with pH effects. The results of biological studies also indicate the highest pharmacological potential of the analogue in the case where the effects of dual fluorescence emission are observed, which predisposes this particular group of fluorophores as effective fluorescence probes or potential pharmaceuticals with antimycotic properties.


Assuntos
Antifúngicos/química , Tiadiazóis/química , Absorção de Radiação , Antifúngicos/farmacologia , Antifúngicos/efeitos da radiação , Candida/efeitos dos fármacos , Fluorescência , Tiadiazóis/farmacologia , Tiadiazóis/efeitos da radiação , Raios Ultravioleta
9.
Soft Matter ; 14(6): 894-900, 2018 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-29303200

RESUMO

The bottom-up approach in synthetic biology involves the engineering of synthetic cells by designing biological and chemical building blocks, which can be combined in order to mimic cellular functions. The first step for mimicking a living cell is the design of an appropriate compartment featuring a multifunctional membrane. This is of particular interest since it allows for the selective attachment of different groups or molecules to the membrane. In this context, we report on a modular approach for polymeric vesicles, so-called polymersomes, with a multifunctional surface, namely hydroxyl, alkyne and acrylate groups. We demonstrate that the surface of the polymersome can be functionalized to facilitate imaging, via fluorescent dyes, or to improve the specific adhesion to surfaces by using a biotin functionalization. This generally applicable multifunctionality allows for the covalent integration of various molecules in the membrane of a synthetic cell.

10.
J Fluoresc ; 28(1): 65-77, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28889356

RESUMO

The article presents the results of fluorescence analyses of 2-methylamino-5-(2,4-dihydroxyphenyl)-1,3,4-thiadiazole (MDFT) in an aqueous environment. MDFT dissolved in aqueous solutions with a pH value in the range from 1 to 4.5 yielded an interesting effect of two clearly separated fluorescence emissions. In turn, a single fluorescence was observed in MDFT dissolved in water solutions with a pH value from 4.5 to 12. As it was suggested in the previous investigations of other 1,3,4-thiadiazole compounds, these effects may be associated with conformational changes in the structure of the analysed molecule accompanied by aggregation effects. Crystallographic data showed that the effect of the two separated fluorescence emissions occurred in a conformation with the -OH group in the resorcyl ring bound on the side of the sulphur atom from the 1,3,4-thiadiazole ring. The hypothesis of aggregation as the mechanism involved in the change in the spectral properties at low pH is supported by the results of (Time-Dependent) Density Functional Theory calculations. The possibility of rapid analysis of conformational changes with the fluorescence spectroscopy technique may be rather important outcome obtained from the spectroscopic studies presented in this article. Additionally, the presented results seem to be highly important as they can be easily observed in solutions and biologically important samples.

11.
Cardiovasc Drugs Ther ; 32(2): 169-173, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29623481

RESUMO

PURPOSE: Antazoline is a first-generation antihistaminic agent with additional anticholinergic properties and antiarrhythmic potential. Recent data shows its high effectiveness in sinus rhythm restoration among patients with paroxysmal atrial fibrillation. The effect of antazoline on electrophysiological parameters of the heart in vivo has not yet been examined. The aim of this study was to evaluate changes in electrophysiological parameters of the heart muscle and conduction system as a response to increasing doses of antazoline. METHODS: After successful ablation of supraventricular arrhythmias, the electrophysiological parameters: sinus rhythm cycle length (SRCL), AH, HV, QRS, QT, QTc intervals, Wenckebach point (WP), sinus node recovery period (SNRT), intra- (hRA-CSos) and interatrial conduction time (hRA-CSd), right and left atrium refractory period (RA-; LA-ERP), and atrioventricular node refractory period (AVN-ERP) were assessed initially and after 100, 200, and 300 mg of antazoline given intravenously. RESULTS: Fifteen patients (8 males, 19-72 years old) undergoing EPS and RF ablation were enrolled. After 100 mg bolus, a significant reduction in SRCL was noticed. After antazoline administration, significant prolongation of HV, QRS, QTc, hRA-CSos, hRA-CSd intervals, RA- and LA-ERP and reduction of SRCL were observed. After a total dose of 300 mg, QT interval prolonged significantly. Increasing the dose of antazoline had no impact on AH, Wenckebach point, AVN-ERP, and SNRT. CONCLUSION: Antazoline has an effect on electrophysiological parameters of the atrial muscle and has rapid onset of action. No negative effect on sinus node function and atrioventricular conduction in a unique property among antiarrhythmic drugs.


Assuntos
Potenciais de Ação/efeitos dos fármacos , Antazolina/administração & dosagem , Antiarrítmicos/administração & dosagem , Flutter Atrial/tratamento farmacológico , Átrios do Coração/efeitos dos fármacos , Sistema de Condução Cardíaco/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Músculos Papilares/efeitos dos fármacos , Taquicardia por Reentrada no Nó Atrioventricular/tratamento farmacológico , Adulto , Idoso , Flutter Atrial/diagnóstico , Flutter Atrial/fisiopatologia , Flutter Atrial/cirurgia , Ablação por Cateter , Relação Dose-Resposta a Droga , Feminino , Átrios do Coração/fisiopatologia , Átrios do Coração/cirurgia , Sistema de Condução Cardíaco/fisiopatologia , Sistema de Condução Cardíaco/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Músculos Papilares/fisiopatologia , Músculos Papilares/cirurgia , Taquicardia por Reentrada no Nó Atrioventricular/diagnóstico , Taquicardia por Reentrada no Nó Atrioventricular/fisiopatologia , Taquicardia por Reentrada no Nó Atrioventricular/cirurgia , Resultado do Tratamento , Adulto Jovem
12.
Rheumatol Int ; 38(6): 959-974, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29492586

RESUMO

Thrombosis and cardiovascular complications are common manifestations of a variety of pathological conditions, including infections and chronic inflammatory diseases. Hence, there is great interest in determining the hitherto unforeseen immune role of the main blood coagulation executor-the platelet. Platelets store and release a plethora of immunoactive molecules, generate microparticles, and interact with cells classically belonging to the immune system. The observed effects of platelet involvement in immune processes, especially in autoimmune diseases, are conflicting-from inciting inflammation to mediating its resolution. An in-depth understanding of the role of platelets in inflammation and immunity could open new therapeutic pathways for patients with autoimmune disorders. This review aims to summarize the current knowledge on the role of platelets in the patomechanisms of autoimmune disorders and suggests directions for future research.


Assuntos
Imunidade Adaptativa/imunologia , Doenças Autoimunes/imunologia , Coagulação Sanguínea , Plaquetas/fisiologia , Imunidade Inata/imunologia , Inflamação/imunologia , Micropartículas Derivadas de Células , Humanos , Ativação Plaquetária/imunologia , Ativação Plaquetária/fisiologia
13.
Langmuir ; 30(39): 11650-9, 2014 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-25216210

RESUMO

We report on adsorption of lysozyme (LYS), ovalbumin (OVA), or ovotransferrin (OVT) on particles of a synthetic smectite (synthetic layered aluminosilicate). In our approach we used atomic force microscopy (AFM) and quartz crystal microbalance (QCM) to study the protein-smectite systems in water solutions at pH ranging from 4 to 9. The AFM provided insights into the adhesion forces of protein molecules to the smectite particles, while the QCM measurements yielded information about the amounts of the adsorbed proteins, changes in their structure, and conditions of desorption. The binding of the proteins to the smectite surface was driven mainly by electrostatic interactions, and hence properties of the adsorbed layers were controlled by pH. At high pH values a change in orientation of the adsorbed LYS molecules and a collapse or desorption of OVA layer were observed. Lowering pH to the value ≤ 4 caused LYS to desorb and swelling the adsorbed OVA. The stability of OVT-smectite complexes was found the lowest. OVT revealed a tendency to desorb from the smectite surface at all investigated pH. The minimum desorption rate was observed at pH close to the isoelectric point of the protein, which suggests that nonspecific interactions between OVT and smectite particles significantly contribute to the stability of these complexes.


Assuntos
Proteínas Imobilizadas/química , Silicatos/química , Adsorção , Animais , Ouro/química , Concentração de Íons de Hidrogênio , Técnicas de Microbalança de Cristal de Quartzo , Silício/química , Propriedades de Superfície
14.
Phys Chem Chem Phys ; 16(38): 20514-23, 2014 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-25141995

RESUMO

A novel method for investigating the multicenter bonding patterns in molecular systems by means of the so-called Electron Density of Delocalized Bonds (EDDB) is introduced and discussed. The EDDB method combines the concept of Jug's bond-order orbitals and the indirect ("through-bridge") interaction formalism and opens up new opportunities for studying the interplay between different atomic interactions as well as their impact on both local and global resonance stabilization in systems of conjugated bonds. Using several illustrative examples we demonstrate that the EDDB approach allows for a reliable quantitative description of diverse multicenter delocalization phenomena (with special regard to evaluation of the aromatic stabilization in molecular systems) within the framework of a consistent theoretical paradigm.

15.
Prz Menopauzalny ; 13(3): 180-5, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26327852

RESUMO

AIM OF THE STUDY: To compare Piver III radical hysterectomy (RH) with nerve-sparing radical hysterectomy (NSRH) for cervical cancer patients in terms of postoperative physiology of pelvic autonomic nerves and perioperative complications. MATERIAL AND METHODS: Seventy-three consecutive patients with invasive cervical cancer underwent RH (53 cases) or NSRH (20 cases) from 2001 to 2012 at the Department of Gynecology and Gynecologic Oncology of Polish Mother's Memorial Hospital - Research Institute in Lódz. RESULTS: Compared with patients treated with RH, patients who underwent NSRH presented no significant difference in terms of operative time (146 vs. 143 minutes, p > 0.05), blood loss and hospital stay (9.2 vs. 7.5 days, p > 0.05). A positive surgical margin was found in 6 cases of RH. No serious surgical complications were found in the NSRH group, while there were 4 cases in the RH group. CONCLUSIONS: Nerve-sparing radical hysterectomy is safe and feasible surgical management for cervical cancer patients, which should improve the physiology of the pelvic autonomic nerve system postoperatively. The technique is relatively new and its oncologic efficiency has not been fully established yet, moreover it requires sophisticated anatomical knowledge and high operative skills.

16.
Langmuir ; 29(28): 8845-55, 2013 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-23777243

RESUMO

The polymeric ouzo effect, a nanoprecipitation process, is used for the preparation of polysaccharide-based nanoparticles. Dextran, pullulan, and starch were esterified with hydrophobic carboxylic acid anhydrides to obtain hydrophobic polysaccharides, which are insoluble in water. The additional introduction of methacroyl residues offers the possibility to cross-link the generated nanostructures, which become insoluble in organic solvents. To make use of the ouzo effect for the formation of nanoparticles, the polymer has to be soluble in an organic solvent, which is miscible with water. Here, acetone and THF were used. Immediately after the organic polymer solution is added to water, nanoparticles are generated. The size of the nanoparticles can be adjusted between 50 and 200 nm by changing the concentration of the initial polysaccharide solution. The degree of hydrophobic substitution was shown to have a very minor effect on the particle size. Dispersions with solids contents of up to 2% were obtained. Furthermore, the mechanical properties of the nanoparticles were investigated with force microscopy, and it was shown by fluorescence correlation spectroscopy that a fluorescent dye could be encapsulated in the nanoparticles by the applied nanoprecipitation procedure.

17.
Ther Innov Regul Sci ; 57(4): 839-848, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36972010

RESUMO

Since the release of ICH E6(R2), multiple efforts have been made to interpret the requirements and suggest ways of implementing quality tolerance limits (QTLs) alongside existing risk-based quality management methodologies. While these efforts have contributed positively to developing a common understanding of QTLs, some uncertainty remains regarding implementable approaches. In this article, we review the approaches taken by some leading biopharmaceutical companies, offering recommendations for how to make QTLs most effective, what makes them ineffective, and several case studies to illustrate these concepts. This includes how best to choose QTL parameters and thresholds for a given study, how to differentiate QTLs from key risk indicators, and how QTLs relate to critical-to-quality factors and the statistical design of the trials.


Assuntos
Produtos Biológicos , Locos de Características Quantitativas , Gestão de Riscos
18.
iScience ; 26(7): 107004, 2023 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-37416464

RESUMO

Most antimicrobial peptides (AMPs) exert their microbicidal activity through membrane permeabilization. The designed AMP EcDBS1R4 has a cryptic mechanism of action involving the membrane hyperpolarization of Escherichia coli, suggesting that EcDBS1R4 may hinder processes involved in membrane potential dissipation. We show that EcDBS1R4 can sequester cardiolipin, a phospholipid that interacts with several respiratory complexes of E. coli. Among these, F1FO ATP synthase uses membrane potential to fuel ATP synthesis. We found that EcDBS1R4 can modulate the activity of ATP synthase upon partition to membranes containing cardiolipin. Molecular dynamics simulations suggest that EcDBS1R4 alters the membrane environment of the transmembrane FO motor, impairing cardiolipin interactions with the cytoplasmic face of the peripheral stalk that binds the catalytic F1 domain to the FO domain. The proposed mechanism of action, targeting membrane protein function through lipid reorganization may open new venues of research on the mode of action and design of other AMPs.

19.
Adv Sci (Weinh) ; 10(31): e2301606, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37705095

RESUMO

ATP synthases are proteins that catalyse the formation of ATP through the rotatory movement of their membrane-spanning subunit. In mitochondria, ATP synthases are found to arrange as dimers at the high-curved edges of cristae. Here, a direct link is explored between the rotatory movement of ATP synthases and their preference for curved membranes. An active curvature sorting of ATP synthases in lipid nanotubes pulled from giant vesicles is found. Coarse-grained simulations confirm the curvature-seeking behaviour of rotating ATP synthases, promoting reversible and frequent protein-protein contacts. The formation of transient protein dimers relies on the membrane-mediated attractive interaction of the order of 1.5 kB T produced by a hydrophobic mismatch upon protein rotation. Transient dimers are sustained by a conic-like arrangement characterized by a wedge angle of θ ≈ 50°, producing a dynamic coupling between protein shape and membrane curvature. The results suggest a new role of the rotational movement of ATP synthases for their dynamic self-assembly in biological membranes.


Assuntos
Mitocôndrias , Membranas Mitocondriais , Rotação , Membranas Mitocondriais/metabolismo , Mitocôndrias/metabolismo , Membrana Celular/metabolismo , Trifosfato de Adenosina/metabolismo
20.
Langmuir ; 28(34): 12629-36, 2012 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-22860888

RESUMO

Poly(dimethylsiloxane)-block-poly(2-methyloxazoline) (PDMS-b-PMOXA) vesicles were characterized by a combination of dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryo-TEM), and atomic force microscopy imaging and force spectroscopy (AFM). From DLS data, a hydrodynamic radius of ~150 nm was determined, and cryo-TEM micrographs revealed a bilayer thickness of ~16 nm. In AFM experiments on a silicon wafer substrate, adsorption led to a stable spherical caplike conformation of the polymersomes, whereas on mica, adsorption resulted also in vesicle fusion and formation of bilayer patches or multilayer stacks. This indicates a delicate balance between the mechanical stability of PDMS-b-PMOXA polymersomes on one hand and the driving forces for spreading on the other. A Young's modulus of 17 ± 11 MPa and a bending modulus of 7 ± 5 × 10(-18) J were derived from AFM force spectroscopy measurements. Therefore, the elastic response of the PDMS-b-PMOXA polymersomes to external stimuli is much closer to that of lipid vesicles compared to other types of polymersomes, such as polystyrene-block-poly(acrylic acid) (PS-b-PAA).

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