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1.
J Am Chem Soc ; 146(23): 15965-15976, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38620052

RESUMO

In nature, chemotactic interactions are ubiquitous and play a critical role in driving the collective behavior of living organisms. Reproducing these interactions in vitro is still a paramount challenge due to the complexity of mimicking and controlling cellular features, such as tangled metabolic networks, cytosolic macromolecular crowding, and cellular migration, on a microorganism size scale. Here, we generate enzymatically active cell-sized droplets able to move freely, and by following a chemical gradient, able to interact with the surrounding droplets in a collective manner. The enzyme within the droplets generates a pH gradient that extends outside the edge of the droplets. We discovered that the external pH gradient triggers droplet migration and controls its directionality, which is selectively toward the neighboring droplets. Hence, by changing the enzyme activity inside the droplet, we tuned the droplet migration speed. Furthermore, we showed that these cellular-like features can facilitate the reconstitution of a simple and linear protometabolic pathway and increase the final reaction product generation. Our work suggests that simple and stable membraneless droplets can reproduce complex biological phenomena, opening new perspectives as bioinspired materials and synthetic biology tools.


Assuntos
Quimiotaxia , Concentração de Íons de Hidrogênio , Tamanho da Partícula
2.
Biomacromolecules ; 24(7): 3304-3312, 2023 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-37364888

RESUMO

Fluids composed of biosourced rod-like colloids (RC) and rod-like polymers (RP) have been extensively studied due to various promising applications relying on their flow-induced orientation (e.g., fiber spinning). However, the relationship between RC and RP alignment and the resulting rheological properties is unclear due to experimental challenges. We investigate the alignment-rheology relationship for a variety of biosourced RC and RP, including cellulose-based particles, filamentous viruses, and xanthan gum, by simultaneous measurements of the shear viscosity and fluid anisotropy under rheometric shear flows. For each system, the RC and RP contribution to the fluid viscosity, captured by the specific viscosity ηsp, follows a universal trend with the extent of the RC and RP alignment independent of concentration. We further exploit this unique rheological-structural link to retrieve a dimensionless parameter (ß) directly proportional to ηsp at zero shear rate (η0,sp), a parameter often difficult to access from experimental rheometry for RC and RP with relatively long contour lengths. Our results highlight the unique link between the flow-induced structural and rheological changes occurring in RC and RP fluids. We envision that our findings will be relevant in building and testing microstructural constitutive models to predict the flow-induced structural and rheological evolution of fluids containing RC and RP.


Assuntos
Coloides , Polímeros , Polímeros/química , Celulose , Reologia , Viscosidade
3.
J Chem Phys ; 158(3): 034901, 2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36681636

RESUMO

In this work, we studied TEMPO-oxidized cellulose nanofibril (OCNF) suspensions in the presence of diverse surfactants. Using a combination of small angle neutron scattering (SANS) and rheology, we compared the physical properties of the suspensions with their structural behavior. Four surfactants were studied, all with the same hydrophobic tail length but different headgroups: hexaethylene glycol mono-n-dodecyl ether (C12EO6, nonionic), sodium dodecyl sulfate (SDS, anionic), cocamidopropyl betaine (CapB, zwitterionic), and dodecyltrimethylammonium bromide (DTAB, cationic). Contrast variation SANS studies using deuterated version of C12EO6 or SDS, or by varying the D2O/H2O ratio of the suspensions (with CapB), allowed focusing only on the structural properties of OCNFs or surfactant micelles. We showed that, in the concentration range studied, for C12EO6, although the nanofibrils are concentrated thanks to an excluded volume effect observed in SANS, the rheological properties of the suspensions are not affected. Addition of SDS or CapB induces gelation for surfactant concentrations superior to the critical micellar concentration (CMC). SANS results show that attractive interactions between OCNFs arise in the presence of these anionic or zwitterionic surfactants, hinting at depletion attraction as the main mechanism of gelation. Finally, addition of small amounts of DTAB (below the CMC) allows formation of a tough gel by adsorbing onto the OCNF surface.


Assuntos
Celulose Oxidada , Tensoativos , Tensoativos/química , Espalhamento a Baixo Ângulo , Dodecilsulfato de Sódio/química
4.
Medicina (Kaunas) ; 57(10)2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34684086

RESUMO

Familial Mediterranean fever (FMF) is a genetic autoinflammatory disease with autosomal recessive transmission, characterized by periodic fever attacks with self-limited serositis. Secondary amyloidosis due to amyloid A renal deposition represents the most fearsome complication in up to 8.6% of patients. Amyloidosis A typically reveals a nephrotic syndrome with a rapid progression to end-stage kidney disease still. It may also involve the cardiovascular system, the gastrointestinal tract and the central nervous system. Other glomerulonephritis may equally affect FMF patients, including vasculitis such as IgA vasculitis and polyarteritis nodosa. A differential diagnosis among different primary and secondary causes of nephrotic syndrome is mandatory to determine the right therapeutic choice for the patients. Early detection of microalbuminuria is the first signal of kidney impairment in FMF, but new markers such as Neutrophil Gelatinase-Associated Lipocalin (NGAL) may radically change renal outcomes. Serum amyloid A protein (SAA) is currently considered a reliable indicator of subclinical inflammation and compliance to therapy. According to new evidence, SAA may also have an active pathogenic role in the regulation of NALP3 inflammasome activity as well as being a predictor of the clinical course of AA amyloidosis. Beyond colchicine, new monoclonal antibodies such as IL-1 inhibitors anakinra and canakinumab, and anti-IL-6 tocilizumab may represent a key in optimizing FMF treatment and prevention or control of AA amyloidosis.


Assuntos
Amiloidose , Febre Familiar do Mediterrâneo , Nefropatias , Amiloidose/diagnóstico , Amiloidose/tratamento farmacológico , Amiloidose/etiologia , Colchicina/uso terapêutico , Febre Familiar do Mediterrâneo/complicações , Febre Familiar do Mediterrâneo/diagnóstico , Febre Familiar do Mediterrâneo/tratamento farmacológico , Humanos , Rim
5.
Biomacromolecules ; 21(12): 5315-5322, 2020 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-33202126

RESUMO

The use of hydrogen peroxide-releasing enzymes as a component to produce alternative and sustainable antimicrobial materials has aroused interest in the scientific community. However, the preparation of such materials requires an effective enzyme binding method that often involves the use of expensive and toxic chemicals. Here, we describe the development of an enzyme-based hydrogen peroxide-producing regenerated cellulose film (RCF) in which a cellobiohydrolase (TrCBHI) and a cellobiose dehydrogenase (MtCDHA) were efficiently adsorbed, 90.38 ± 2.2 and 82.40 ± 5.7%, respectively, without making use of cross-linkers. The enzyme adsorption kinetics and binding isotherm experiments showed high affinity of the proteins possessing cellulose-binding modules for RCF, suggesting that binding on regenerated cellulose via specific interactions can be an alternative method for enzyme immobilization. Resistance to compression and porosity at a micrometer scale were found to be tunable by changing cellulose concentration prior to film regeneration. The self-degradation process, triggered by stacking TrCBHI and MtCDHA (previously immobilized onto separate RCF), produced 0.15 nmol/min·cm2 of H2O2. Moreover, the production of H2O2 was sustained for at least 24 h reaching a concentration of ∼2 mM. The activity of MtCDHA immobilized on RCF was not affected by reuse for at least 3 days (1 cycle/day), suggesting that no significant enzyme leakage occurred in that timeframe. In the material herein designed, cellulose (regenerated from a 1-ethyl-3-methylimidazolium acetate/dimethyl sulfoxide (DMSO) solution) serves both as support and substrate for the immobilized enzymes. The sequential reaction led to the production of H2O2 at a micromolar-millimolar level revealing the potential use of the material as a self-degradable antimicrobial agent.


Assuntos
Celulose , Peróxido de Hidrogênio , Adsorção , Celulose 1,4-beta-Celobiosidase , Enzimas Imobilizadas
6.
Soft Matter ; 16(13): 3303-3310, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32173723

RESUMO

The effect of the filler size on the structural and mechanical properties of an attractive fibrillated network composed of oxidised cellulose nanofibrils (OCNF) in water was investigated. Silica nanoparticles with a diameter of ca. 5 nm (SiNp5) and and ca. 158 nm (SiNp158) were chosen as non-interacting fillers of the OCNF network. These filler sizes were chosen, respectively, to have a particle size which was either similar to that of the network mesh size or much larger than it. Contrast matched small angle neutron scattering (SANS) experiments revealed that the presence of the fillers (SiNp5 and SiNp158) did not perturb the structural properties of the OCNF network at the nanometer scale. However, the filler size difference strongly affected the mechanical properties of the hydrogel upon large amplitude oscillatory shear. The presence of the smaller filler, SiNp5, preserved the mechanical properties of the hydrogels, while the larger filler, SiNp158, allowed a smoother breakage of the network and low network recoverability after breakage. This study showed that the filler-to-mesh size ratio, for non-interacting fillers, is pivotal for tailoring the non-linear mechanical properties of the gel, such as yielding and flow.

7.
Soft Matter ; 16(2): 357-365, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31720672

RESUMO

Interfacial gels, obtained by the interaction of water-dispersible oxidised cellulose nanofibrils (OCNF) and oil-soluble oleylamine (OA), were produced across water/oil (W/O) interfaces. Surface rheology experiments showed that the complexation relies on the charge coupling between the negatively-charged OCNF and OA. Complexation across the W/O interface was found to be dependent on the ζ-potential of the OCNF (modulated by electrolyte addition), leading to different interfacial properties. Spontaneous OCNF adsorption at the W/O interface occurred for particles with ζ-potential more negative than -30 mV, resulting in the formation of interfacial gels; whilst for particles with ζ-potential of ca. -30 mV, spontaneous adsorption occurred, coupled with augmented interfibrillar interactions, yielding stronger and tougher interfacial gels. On the contrary, charge neutralisation of OCNF (ζ-potential values more positive than -30 mV) did not allow spontaneous adsorption of OCNF at the W/O interface. In the case of favourable OCNF adsorption, the interfacial gel was found to embed oil-rich droplets - a spontaneous emulsification process.

8.
Soft Matter ; 16(20): 4887-4896, 2020 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-32424387

RESUMO

In this work, we investigated the effect of adding surfactant mixtures on the rheological properties of TEMPO-oxidized cellulose nanofibril (OCNF) saline dispersions. Three surfactant mixtures were studied: cocamidopropyl betaine (CAPB)/sodium dodecyl sulfate (SDS), which forms wormlike micelles (WLMs); cocamidopropylamine oxide (CAPOx)/SDS, which forms long rods; and CAPB/sodium lauroyl sarcosinate (SLS), which forms spherical micelles. The presence of micelles in these surfactant mixtures, independent of their morphology, leads to an increase of tan δ, making the gels less solid-like, therefore acting as a plasticizer. WLMs were able to suppress strain stiffening normally observed in OCNF gels at large strains. OCNF/WLM gels have lower G' values than OCNF gels while the other micellar morphologies have a reduced impact on G'. The presence of unconnected micelles leads to increased dissipative deformation in OCNF gels without affecting the connectivity of the fibrils, while the presence of entangled micelles interferes with the OCNF network.

9.
Soft Matter ; 14(45): 9243-9249, 2018 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-30418451

RESUMO

Solvent-induced physical hydrogels of TEMPO-oxidized cellulose nanofibrils (OCNFs) were obtained from aqueous/alcoholic dispersions of fibrils in lower alcohols, namely, methanol, ethanol, 1-propanol and 2-propanol. The sol-gel transition occurs above a critical alcohol concentration of ca. 30 wt% for all alcohols tested. The rheological properties of the hydrogels depend on the nature of the alcohol: for ethanol, 1-propanol and 2-propanol the magnitude of the shear storage modulus follows the alcohol hydrophilicity, whilst methanol produces the weakest gels in the group. Above a second critical concentration, ca. 60 wt% alcohol, phase separation is observed as the gels undergo syneresis. Analysis of small-angle X-ray scattering data shows that the OCNFs may be modelled as rigid rods. In the presence of lower alcohols, attractive interactions between nanofibrils are present and, above the alcohol concentration leading to gelation, an increase of the OCNF cross-section is observed, suggesting alcohol induced aggregation of nanofibrils.

10.
Soft Matter ; 14(38): 7793-7800, 2018 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-30109338

RESUMO

Zwitterionic cellulose nanofibrils (ZCNFs) with an isoelectric point of 3.4 were obtained by grafting glycidyltrimethylammonium chloride onto TEMPO/NaBr/NaOCl-oxidised cellulose nanofibrils. The ZCNF aqueous dispersions were characterized via transmission electron microscopy, rheology and small angle neutron scattering, revealing a fibril-bundle structure with pronounced aggregation at pH 7. Surfactants were successfully employed to tune the stability of the ZCNF dispersions. Upon addition of the anionic surfactant, sodium dodecyl sulfate, the ZCNF dispersion shows individualized fibrils due to electrostatic stabilization. In contrast, upon addition of the cationic species dodecyltrimethylammonium bromide, the dispersion undergoes charge neutralization, leading to more pronounced flocculation.

11.
Phys Chem Chem Phys ; 20(23): 16012-16020, 2018 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-29850680

RESUMO

The structure of dispersions of TEMPO-oxidised cellulose nanofibrils (OCNF), at various concentrations, in water and in NaCl aqueous solutions, was probed using small angle X-ray scattering (SAXS). OCNF are modelled as rod-like particles with an elliptical cross-section of 10 nm and a length greater than 100 nm. As OCNF concentration increases above 1.5 wt%, repulsive interactions between fibrils are evidenced, modelled by the interaction parameter νRPA > 0. This corresponds to gel-like behaviour, where G' > G'' and the storage modulus, G', shows weak frequency dependence. Hydrogels can also be formed at OCNF concentration of 1 wt% in 0.1 M NaCl(aq). SAXS patterns shows an increase of the intensity at low angle that is modelled by attractive interactions (νRPA < 0) between OCNF, arising from the screening of the surface charge of the fibrils. Results are supported by ζ potential and cryo-TEM measurements.

12.
Expert Opin Investig Drugs ; 33(4): 319-334, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38429874

RESUMO

INTRODUCTION: Chronic kidney disease (CKD) is widespread throughout the world, with a high social and health impact. It is considered a 'silent killer' for its sudden onset without symptoms in the early stages of the disease. The main goal of nephrologists is to slow the progression of kidney disease and treat the associated symptoms with a range of new medications. AREAS COVERED: The aim of this systematic review is to analyze the new investigational drugs for the treatment of chronic renal failure. Data were obtained from the available scientific literature and from the ClinicalTrials.gov website. EXPERT OPINION: Among the drugs currently being researched, SGLT2 inhibitors appear to be the most promising drugs for the treatment of CKD, has they have slower progression of CKD and protection of cardiorenal function. An important role in the future of CKD treatment is played by autologous cell-therapy, which appears to be a new frontier in the treatment of CKD. Other therapeutic strategies are currently being investigated and have been shown to slow the progression of CKD. However, further studies are needed to determine whether these approaches may offer benefits in slowing the progression of CKD in the near future.


Assuntos
Diabetes Mellitus Tipo 2 , Falência Renal Crônica , Insuficiência Renal Crônica , Inibidores do Transportador 2 de Sódio-Glicose , Humanos , Drogas em Investigação/uso terapêutico , Falência Renal Crônica/prevenção & controle , Insuficiência Renal Crônica/tratamento farmacológico , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico
13.
Biomicrofluidics ; 17(2): 021301, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37035099

RESUMO

Naturally derived colloidal rods (CR) are promising building blocks for developing sustainable soft materials. Engineering new materials based on naturally derived CR requires an in-depth understanding of the structural dynamics and self-assembly of CR in dispersion under processing conditions. With the advancement of microfabrication techniques, many microfluidic platforms have been employed to study the structural dynamics of CR under flow. However, each microfluidic design has its pros and cons which need careful evaluation in order to fully meet the experimental goal and correctly interpret the data. We analyze recent results obtained from naturally derived CR and relevant rod-like macromolecules under microfluidic flows, with emphasis on the dynamical behavior in shear- and extensional-dominated flows. We highlight the key concepts required in order to assess and evaluate the results obtained from different CR and microfluidic platforms as a whole and to aid interconnections with neighboring fields. Finally, we identify and discuss areas of interest for future research directions.

14.
J Colloid Interface Sci ; 638: 487-497, 2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-36758259

RESUMO

HYPOTHESIS: Protein nanofibrils (PNF) resulting from the self-assembly of proteins or peptides can present structural ordering triggered by numerous factors, including the shear flow. We hypothesize that i) depending on the contour length of the PNF and the magnitude of the shear rate applied to the PNF dispersion, they exhibit specific orientation, and ii) it is possible to predict the alignment of PNF by establishing a flow-alignment relationship. Understanding such a relationship is pivotal to improving the fundamental knowledge and application of fibril systems. EXPERIMENTS: We use ß-lactoglobulin PNF aqueous dispersions with different average contour lengths but equal persistence lengths. We employ simple shear-dominated microfluidic devices with state-of-the-art imaging techniques: flow-induced birefringence (FIB) and micro-particle image velocimetry (µ-PIV), to probe the effect of shear flow on PNF alignment. FINDINGS: We provide an empirical relationship connecting the birefringence Δn (quantifying the extent of PNF alignment), and the Péclet number Pe (correlating the shear rate of the flow relative to the rotational diffusion of PNF) to understand the flow-alignment behavior of PNF under shear-dominated flows. Furthermore, we assess the alignment and flow profile of PNF at both high and low flow rates. The length of PNF emerges as a controlling parameter capable of modulating PNF alignment at specific shear rates. Our results shed new insights into the hydrodynamic behavior of PNF, which is highly relevant to various industrial processes involving the fibril systems.


Assuntos
Proteínas , Reologia
15.
Nutrients ; 15(14)2023 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-37513579

RESUMO

Hyperphosphatemia is a common complication in advanced chronic kidney disease and contributes to cardiovascular morbidity and mortality. The present narrative review focuses on the management of phosphatemia in uremic patients receiving peritoneal dialysis. These patients frequently develop hyperphosphatemia since phosphate anion behaves as a middle-size molecule despite its low molecular weight. Accordingly, patient transporter characteristics and peritoneal dialysis modalities and prescriptions remarkably influence serum phosphate control. Given that phosphate peritoneal removal is often insufficient, especially in lower transporters, patients are often prescribed phosphate binders whose use in peritoneal dialysis is primarily based on clinical trials conducted in hemodialysis because very few studies have been performed solely in peritoneal dialysis populations. A crucial role in phosphate control among peritoneal dialysis patients is played by diet, which must help in reducing phosphorous intake while preventing malnutrition. Moreover, residual renal function, which is preserved in most peritoneal dialysis patients, significantly contributes to maintaining phosphate balance. The inadequate serum phosphate control observed in many patients on peritoneal dialysis highlights the need for large and well-designed clinical trials including exclusively peritoneal dialysis patients to evaluate the effects of a multiple therapeutic approach on serum phosphate control and on hard clinical outcomes in this high-risk population.


Assuntos
Hiperfosfatemia , Diálise Peritoneal , Insuficiência Renal Crônica , Humanos , Fosfatos , Hiperfosfatemia/etiologia , Hiperfosfatemia/prevenção & controle , Hiperfosfatemia/epidemiologia , Diálise Peritoneal/efeitos adversos , Diálise Renal/efeitos adversos , Insuficiência Renal Crônica/terapia , Insuficiência Renal Crônica/complicações
16.
Expert Opin Pharmacother ; 24(15): 1737-1746, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37527180

RESUMO

INTRODUCTION: Among the clinical and metabolic complications of progressive chronic kidney disease (CKD), CKD-mineral bone disorder (CKD-MBD) significantly contributes to morbidity and mortality. While overt and persistent hyperphosphatemia is typical of advanced CKD and requires treatment, other abnormalities of calcium/phosphate metabolism begin to occur since the early stages of the disease. AREAS COVERED: We searched on the PubMed database, without restrictions for language or time range, for randomized clinical trials and meta-analyses investigating phosphate-lowering therapies. The various phosphate binders show different safety profiles and diverse effects on calcium/phosphate metabolism and vascular calcification. The in-depth knowledge of the characteristics of these drugs is crucial to ensure adequate treatment to CKD patients. EXPERT OPINION: A proper control of serum phosphate can be achieved using phosphate binders. These medications may induce side effects. Moreover, data on their impact on clinical outcomes are partly controversial or scarce, especially for the new generation drugs. Hyperphosphatemia favors cardiovascular disease and increases the risk for CKD progression. These effects are partially mediated by fibroblast growth factor 23 (FGF23), a phosphaturic hormone that raises to maintain normal serum phosphate. Since there are no data supporting the use of phosphate-lowering agents when phosphataemia is normal, a key role is played by reducing dietary phosphate intake with the aim to control serum phosphate and the compensatory FGF23 and parathyroid hormone (PTH) increase.


PLAIN LANGUAGE SUMMARY: The progressive reduction in renal function, a condition known as chronic kidney disease (CKD), is characterized by several clinical and metabolic complications. Among them are the alterations of calcium and phosphorous metabolism that are part of the so-called CKD-MBD (chronic kidney disease-mineral bone disorder) and contribute to increase morbidity and mortality, especially due to vascular calcification. Persistent hyperphosphatemia is typical of advanced CKD but other abnormalities occur earlier to maintain normal serum calcium and phosphorus levels. These compensatory mechanisms are also involved in the pathophysiology of CKD-MBD and should be counteracted to improve clinical outcomes of CKD patients. Given the crucial role of hyperphosphatemia, numerous therapeutic strategies have been developed over time to help maintain phosphate serum levels within the normal range and prevent or treat CKD-MBD and its consequences. Phosphate binders act by binding dietary phosphate in the gastrointestinal lumen to prevent its absorption. According to their molecular structure, these drugs can be classified into calcium-based (calcium carbonate, calcium acetate), non-calcium-containing (sevelamer carbonate, sevelamer hydrochloride, lanthanum carbonate), aluminum-containing (aluminum hydroxide), and iron-based (sucroferric oxyhydroxide, ferric citrate) compounds. The various phosphate binders show different safety profiles and diverse effects on calcium/phosphate metabolism and vascular calcification. Despite the ability of hyperphosphatemia to favor CKD-MBD development and cardiovascular risk, there are no data supporting the use of phosphate-lowering agents when serum phosphate is normal also due to the potential adverse effects of long-term therapies. Accordingly, a key role is played by reducing dietary phosphate overload since the first stages of CKD.


Assuntos
Hiperfosfatemia , Insuficiência Renal Crônica , Humanos , Hiperfosfatemia/tratamento farmacológico , Hiperfosfatemia/etiologia , Cálcio , Fosfatos , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/tratamento farmacológico , Hormônio Paratireóideo , Sevelamer/uso terapêutico , Quelantes/efeitos adversos
17.
Microorganisms ; 11(9)2023 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-37764071

RESUMO

The ongoing glomerular damage of infections is not limited to the most widely known form of post-streptococcal glomerulonephritis, which is today less common in the Western world; other forms of glomerulonephritis are associated with several bacterial, viral and parasitic pathogens. The mechanisms responsible range from the direct damage of glomerular cells to the formation and deposition of immunocomplexes to molecular mimicry to the secretion of superantigens. Similarly, in the course of glomerular disease, infections are more frequent than in the general population due to the loss of immunoglobulins in urine and the immunosuppressive agents used to treat the autoimmune disease that decrease the activity of the immune system. Recognizing this two-way link, understanding its pathogenetic mechanism, and identifying the most appropriate therapeutic choice are essential for the personalized management of patients. In this continuously developing field, this short review summarizes the current state of the art as support for physicians, who are increasingly involved in managing patients with glomerular disease and infections.

18.
G Ital Nefrol ; 40(6)2023 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-38156537

RESUMO

Although Randomized clinical trials (RCT) represent the gold standard to compare two or more treatments, the impact of observational studies cannot be ignored. Obviously, these latter are performed on unbalanced sample, and differences among the compared groups could be detected. These differences could have an impact on the estimated association between our allocation and our outcome. To avoid it, some methods should be applied in the analysis of observational cohort. Propensity score (PS) can be considered as a value which sums up and balances the known variables. It aims to adjust or balance the probability of receiving a specific allocation group, and could be used to match, stratify, weight, and perform a covariate adjustment. PS is calculated with a logistic regression, using allocation groups as the outcome. Thanks to PS, we compute the probability of being allocated to one group and we can match patients obtaining two balanced groups. It avoids computing analysis in unbalanced groups. We compared low protein diet (LPD) and the Mediterranean diet in CKD patients and analysed them using the PS methods. Nutritional therapy is fundamental for the prevention, progression and treatment of Chronic Kidney Disease (CKD) and its complications. An individualized, stepwise approach is essential to guarantee high adherence to nutritional patterns and to reach therapeutic goals. The best dietary regimen is still a matter of discussion. In our example, unbalanced analysis showed a significant renal function preservation in LPD, but this correlation was denied after the PS analysis. In conclusion, although unmatched analysis showed differences between the two diets, after propensity analysis no differences were detected. If RCT cannot be performed, balancing the PS score allows to balance the sample and avoids biased results.


Assuntos
Dieta Mediterrânea , Insuficiência Renal Crônica , Humanos , Dieta com Restrição de Proteínas , Pontuação de Propensão
19.
Macromolecules ; 55(13): 5610-5620, 2022 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-35847240

RESUMO

Understanding the hydrodynamic alignment of colloidal rods in polymer solutions is pivotal for manufacturing structurally ordered materials. How polymer crowding influences the flow-induced alignment of suspended colloidal rods remains unclear when rods and polymers share similar length scales. We tackle this problem by analyzing the alignment of colloidal rods suspended in crowded polymer solutions and comparing that to the case where crowding is provided by additional colloidal rods in a pure solvent. We find that the polymer dynamics govern the onset of shear-induced alignment of colloidal rods suspended in polymer solutions, and the control parameter for the alignment of rods is the Weissenberg number, quantifying the elastic response of the polymer to an imposed flow. Moreover, we show that the increasing colloidal alignment with the shear rate follows a universal trend that is independent of the surrounding crowding environment. Our results indicate that colloidal rod alignment in polymer solutions can be predicted on the basis of the critical shear rate at which polymer coils are deformed by the flow, aiding the synthesis and design of anisotropic materials.

20.
Macromolecules ; 55(22): 10031-10042, 2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36438595

RESUMO

We investigate the shear and extensional flow behavior of dispersions composed of two types of worm-like nanoparticles (WLNPs) with comparable cross-sectional diameters, similar persistence lengths but differing contour lengths, and thus differing flexibility. By measuring the flow-induced birefringence (FIB) of WLNP dispersions in two contrasting microfluidic devices, we obtain an experimental quantification of the role of shearing and planar extensional flows at aligning a short and stiff WLNP (S-WLNP) and a relatively long and flexible WLNP (L-WLNP). We show that shear and extensional flows induce the alignment of both types of WLNPs. However, extensional deformations are more effective than shear deformations at triggering the onset of alignment of the WLNP. The difference between shear and extensional deformations for WLNP alignment is explained based on the ratio of extensional and shear viscosity of the solvent fluid (Trouton ratio of the solvent) and a structural parameter related to the WLNP extensibility and flexibility. Under shear flow, these WLNP dispersions display shear-thinning behavior, with an exponential reduction in viscosity with increasing alignment. Under extensional flow, the WLNP alignment leads to extensional thinning, making WLNP ideal additives for industrial and biotechnology formulations exposed to extensional dominated flows (e.g., jetting, spraying, and printing processes).

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