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1.
Artigo em Inglês | MEDLINE | ID: mdl-32540976

RESUMO

Antimicrobial peptides (AMPs) have seen limited clinical use as antimicrobial agents, largely due to issues relating to toxicity, short biological half-life, and lack of efficacy against Gram-negative bacteria. However, the development of novel AMP-nanomedicines, i.e., AMPs entrapped in nanoparticles, has the potential to ameliorate these clinical problems. The authors investigated two novel nanomedicines based on AA139, an AMP currently in development for the treatment of multidrug-resistant Gram-negative infections. AA139 was entrapped in polymeric nanoparticles (PNPs) or lipid-core micelles (MCLs). The antimicrobial activity of AA139-PNP and AA139-MCL was determined in vitro The biodistribution and limiting doses of AA139-nanomedicines were determined in uninfected rats via endotracheal aerosolization. The early bacterial killing activity of the AA139-nanomedicines in infected lungs was assessed in a rat model of pneumonia-septicemia caused by extended-spectrum ß-lactamase-producing Klebsiella pneumoniae In this model, the therapeutic efficacy was determined by once-daily (q24h) administration over 10 days. Both AA139-nanomedicines showed equivalent in vitro antimicrobial activities (similar to free AA139). In uninfected rats, they exhibited longer residence times in the lungs than free AA139 (∼20% longer for AA139-PNP and ∼80% longer for AA139-MCL), as well as reduced toxicity, enabling a higher limiting dose. In rats with pneumonia-septicemia, both AA139-nanomedicines showed significantly improved therapeutic efficacy in terms of an extended rat survival time, although survival of all rats was not achieved. These results demonstrate potential advantages that can be achieved using AMP-nanomedicines. AA139-PNP and AA139-MCL may be promising novel therapeutic agents for the treatment of patients suffering from multidrug-resistant Gram-negative pneumonia-septicemia.


Assuntos
Bacteriemia , Farmacorresistência Bacteriana Múltipla , Infecções por Klebsiella/tratamento farmacológico , Pneumonia Bacteriana , Proteínas Citotóxicas Formadoras de Poros , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Klebsiella pneumoniae , Testes de Sensibilidade Microbiana , Nanomedicina , Pneumonia Bacteriana/tratamento farmacológico , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Ratos , Distribuição Tecidual
2.
Plant Foods Hum Nutr ; 75(4): 592-598, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32920755

RESUMO

Starch structure and bioactive ingredients play an implicit role in the control of glucose release at intestinal level reducing the risk of inadequate metabolic response(s). This study performs a comparative kinetic approach to glucose release from hydrothermally treated (HT) maize (MS) and quinoa (QS) starch. Besides, chia flour (CF) (20%, w/w) was added to evaluate its influence of on the apparent diffusion coefficients (Dapp) when subjected to simulated gastrointestinal digestion. Hepatocyte cultures were used to monitor mitochondrial enzymes activity (test MTT) to bioaccessible glucose concentrations. With an increasing temperature, Dapp for both QS and its mixtures with CF were kept unaltered, while those for MS were disrupted progressively affecting glucose bioaccessibility. Principal component analysis revealed differences between maize and quinoa starches, but common features in the corresponding mixtures with CF. Data indicated that quinoa starch helps controlling glucose release and that addition of CF decreased mitochondrial activity in presence of insulin.


Assuntos
Chenopodium quinoa , Amido , Farinha , Glucose , Zea mays
3.
Biotechnol J ; 18(7): e2300004, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37100765

RESUMO

The development of functional blood vessels is today a fundamental pillar in the evaluation of new therapies and diagnostic agents. This article describes the manufacture and subsequent functionalization, by means of cell culture, of a microfluidic device with a circular section. Its purpose is to simulate a blood vessel in order to test new treatments for pulmonary arterial hypertension. The manufacture was carried out using a process in which a wire with a circular section determines the dimensions of the channel. To fabricate the blood vessel, cells were seeded under rotary cell culture to obtain a homogeneous cell seeding in the inner wall of the devices. This is a simple and reproducible method that allows the generation of blood vessel models in vitro.


Assuntos
Técnicas Analíticas Microfluídicas , Microfluídica , Técnicas de Cultura de Células
4.
Heliyon ; 9(12): e22821, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38125473

RESUMO

Klebsiella pneumoniae are bacteria associated with respiratory tract infections and are increasingly becoming resistant to antibiotics, including carbapenems. Apramycin is a veterinary antibiotic that may have the potential to be re-purposed for use in human health, for example, for the treatment of respiratory tract infections after coupling to inhalable nanoparticles. In the present study, the antibiotic apramycin was formulated with single chain polymeric nanoparticles and tested in free and formulated forms against a set of 13 Klebsiella pneumoniae isolates (from the Netherlands and Pakistan) expressing different aminoglycoside resistance phenotypes. Minimum Inhibitory Concentration, Time Kill Kinetics and biofilm experiments were performed providing evidence for the potential efficacy of apramycin and apramycin-based nanomedicines for the treatment of human Klebsiella pneumonia infections.

5.
NPJ Biofilms Microbiomes ; 8(1): 52, 2022 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-35787627

RESUMO

The extracellular matrix protects biofilm cells by reducing diffusion of antimicrobials. Tobramycin is an antibiotic used extensively to treat P. aeruginosa biofilms, but it is sequestered in the biofilm periphery by the extracellular negative charge matrix and loses its efficacy significantly. Dispersal of the biofilm extracellular matrix with enzymes such as DNase I is another promising therapy that enhances antibiotic diffusion into the biofilm. Here, we combine the charge neutralization of tobramycin provided by dextran-based single-chain polymer nanoparticles (SCPNs) together with DNase I to break the biofilm matrix. Our study demonstrates that the SCPNs improve the activity of tobramycin and DNase I by neutralizing the ionic interactions that keep this antibiotic in the biofilm periphery. Moreover, the detailed effects and interactions of nanoformulations with extracellular matrix components were revealed through time-lapse imaging of the P. aeruginosa biofilms by laser scanning confocal microscopy with specific labeling of the different biofilm components.


Assuntos
Nanopartículas , Tobramicina , Antibacterianos/farmacologia , Biofilmes , Desoxirribonuclease I , Dextranos , Pseudomonas aeruginosa , Tobramicina/farmacologia
6.
Chem Commun (Camb) ; 57(37): 4540-4543, 2021 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-33956004

RESUMO

Herein, we report the evaluation of dextran (DXT) derivatives bearing hydrophobic or hydrophilic functional groups as stabilisers of oil-in-water (O/W) emulsions. All investigated modifications conferred interfacial activity to produce stable O/W emulsions, methacrylate(MA)-functionalised DXT being the most promising stabiliser. A minimum amount of MA was required to obtain stable O/W nanoemulsions, which could be degraded in the presence of lipases.


Assuntos
Dextranos/metabolismo , Proteínas Fúngicas/metabolismo , Lipase/metabolismo , Nanopartículas/metabolismo , Óleos/metabolismo , Água/metabolismo , Dextranos/química , Emulsões/química , Emulsões/metabolismo , Proteínas Fúngicas/química , Interações Hidrofóbicas e Hidrofílicas , Lipase/química , Nanopartículas/química , Óleos/química , Tamanho da Partícula , Água/química
7.
Nutrients ; 13(5)2021 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-34063252

RESUMO

Innate immunity plays a determinant role in high fat diet (HFD)-induced insulin resistance. This study compares the effects of immunonutritional bioactives from Chenopodium quinoa (WQ) or Salvia hispanica L. (Ch) when used to partially replace wheat flour (WB) into bread formulations. These flours were chosen to condition starch and lipid content in the products as well as because their immunonutritional activity. To be administered with different bread formulations, HFD-fed C57BL/6J mice were distributed in different groups: (i) wild type, (ii) displaying inherited disturbances in glucose homeostasis, and (iii) displaying dietary iron-mediated impairment of the innate immune TLR4/TRAM/TRIF pathway. We analyze the effects of the products on glycaemia and insulin resistance (HOMA-IR), plasmatic triglycerides, intestinal and hepatic gene expression and variations of myeloid (MY), and lymphoid (LY) cells population in peripheral blood. Our results show that feeding animals with WQ and Ch formulations influenced the expression of lipogenic and coronary risk markers, thus attaining a better control of hepatic lipid accumulation. WQ and Ch products also improved glucose homeostasis compared to WB, normalizing the HOMA-IR in animals with an altered glucose and lipid metabolism. These positive effects were associated with positive variations in the peripheral myeloid cells population.


Assuntos
Chenopodium quinoa , Farinha , Resistência à Insulina/fisiologia , Células Mieloides/efeitos dos fármacos , Compostos Fitoquímicos/administração & dosagem , Salvia , Animais , Glicemia/imunologia , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Imunidade Inata/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Fígado/metabolismo , Linfócitos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Fenômenos Fisiológicos da Nutrição/efeitos dos fármacos , Fenômenos Fisiológicos da Nutrição/imunologia , Triglicerídeos/sangue
8.
Food Funct ; 11(9): 7994-8002, 2020 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-32841309

RESUMO

High-energy intake causes imbalances in nutrient homeostasis contributing to a high prevalence of metabolic chronic diseases. The extent to what metabolic imbalances can be ameliorated by the inclusion of immunonutritional ingredients obtained from flours favouring nutrient and calorie management remains poorly understood. Herein, it is demonstrated that partial replacement of wheat flour (WB) with that from Chenopodium quinoa varieties [red (RQ, 25% w/w) and white (WQ, 25% w/w)] as well as from Salvia hispanica L., [whole (Ch, 20% w/w) and semi-defatted (Ch_D, 20% w/w)] in bread formulations ameliorates the metabolic and inflammation consequences of high-fat diet consumption in hyperglycaemic animals. Feeding animals with bread formulations replacing wheat flour effectively reduced insulin resistance (by 2-fold, HOMAir). The reduction in starch content did not appear as a determinant of controlling HOMAir. Only animals fed with RQ and Ch diet displayed increased plasma levels of triglycerides, which significantly contributed to mitigate HFD-induced hepatic lipid peroxidation. The latter was increased in animals receiving Ch_D diet, where PUFAs were eliminated from chia's flour. Feeding with WQ and Ch samples caused an upward trend in hepatic TNF-α and IL-6 levels. Despite similarities between immunonutritional agonists in animals fed with RQ and WQ, IL-17 levels were quantified higher for animals fed with WQ. All bread formulations except Ch_D samples significantly increased the hepatic granulocyte-monocyte colony stimulation factor levels. These results indicated that replacement of wheat flour with that from quinoa and chia improved the metabolic imbalances in hyperglycaemic animals.


Assuntos
Pão/análise , Chenopodium quinoa/química , Dieta Hiperlipídica/efeitos adversos , Hiperglicemia/metabolismo , Salvia/química , Animais , Peso Corporal , Farinha/análise , Resistência à Insulina , Interleucina-17 , Interleucina-6 , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Sementes/química , Amido/metabolismo , Triglicerídeos , Triticum , Fator de Necrose Tumoral alfa
9.
Int J Nanomedicine ; 15: 1117-1128, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32110011

RESUMO

INTRODUCTION: Antibiotic-resistant bacteria kill 25,000 people every year in the EU. Patients subject to recurrent lung infections are the most vulnerable to severe or even lethal infections. For these patients, pulmonary delivery of antibiotics would be advantageous, since inhalation can achieve higher concentration in the lungs than iv administration and can provide a faster onset of action. This would allow for the delivery of higher doses and hence reduce the number of treatments required. We report here about a new nanosystem (M33-NS) obtained by capturing SET-M33 peptide on single-chain dextran nanoparticles. SET-M33 is a non-natural antimicrobial peptide synthesized in branched form. This form gives the peptide resistance to degradation in biological fluids. SET-M33 has previously shown efficacy in vitro against about one hundred of Gram-negative multidrug and extensively drug-resistant clinical isolates and was also active in preclinical infection models of pneumonia, sepsis and skin infections. METHODS: The new nanosystem was evaluated for its efficacy in bacteria cells and in a mouse model of pneumonia. Toxicity and genotoxicity were also tested in vitro. Biodistribution and pharmacokinetic studies in healthy rats were carried out using a radiolabeled derivative of the nanosystem. RESULTS: The M33-nanosystem, studied here, showed to be effective against Pseudomonas aeruginosa in time-kill kinetic experiments. Cytotoxicity towards different animal cell lines was acceptable. Lung residence time of the antimicrobial peptide, administered via aerosol in healthy rats, was markedly improved by capturing SET-M33 on dextran nanoparticles. M33-NS was also efficient in eradicating pulmonary infection in a BALB/c mouse model of pneumonia caused by P. aeruginosa. DISCUSSION: This study revealed that the encapsulation of the antimicrobial peptide in dextran nanoparticles markedly improved lung residence time of the peptide administered via aerosol. The result has to be considered among the aims of the development of a new therapeutic option for patients suffering recurrent infections, that will benefit from high local doses of persistent antimicrobials.


Assuntos
Antibacterianos/administração & dosagem , Nanopartículas/administração & dosagem , Peptídeos/administração & dosagem , Infecções por Pseudomonas/tratamento farmacológico , Administração por Inalação , Animais , Antibacterianos/farmacologia , Dextranos , Sistemas de Liberação de Medicamentos/métodos , Feminino , Humanos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Nanopartículas/química , Peptídeos/síntese química , Peptídeos/farmacologia , Pneumonia Bacteriana/tratamento farmacológico , Pseudomonas aeruginosa/efeitos dos fármacos , Ratos , Terapia Respiratória , Distribuição Tecidual
10.
Artigo em Inglês | MEDLINE | ID: mdl-32596225

RESUMO

Cartilage repair still represents a challenge for clinicians and only few effective therapies are nowadays available. In fact, surgery is limited by the tissue poor self-healing capacity while the autologous transplantation is often forsaken due to the poor in vitro expansion capacity of chondrocytes. Biomaterials science offers a unique alternative based on the replacement of the injured tissue with an artificial tissue-mimicking scaffold. However, the implantation surgical practices and the scaffold itself can be a source of bacterial infection that currently represents the first reason of implants failure due to the increasing antibiotics resistance of pathogens. So, alternative antibacterial tools to prevent infections and consequent device removal are urgently required. In this work, the role of Nisin and LL-37 peptides has been investigated as alternative to antibiotics to their antimicrobial performances for direct application at the surgical site or as doping chemicals for devices aimed at articular cartilage repair. First, peptides cytocompatibility was investigated toward human mesenchymal stem cells to determine safe concentrations; then, the broad-range antibacterial activity was verified toward the Gram-positive Staphylococcus aureus and Staphylococcus epidermidis as well as the Gram-negative Escherichia coli and Aggregatibacter actinomycetemcomitans pathogens. The peptides selective antibacterial activity was verified by a cells-bacteria co-culture assay, while chondrogenesis was assayed to exclude any interference within the differentiation route to simulate the tissue repair. In the next phase, the experiments were repeated by moving from the cell monolayer model to 3D cartilage-like spheroids to revisit the peptides activity in a more physiologically relevant environment model. Finally, the spheroid model was applied in a perfusion bioreactor to simulate an infection in the presence of circulating peptides within a physiological environment. Results suggested that 75 µg/ml Nisin can be considered as a very promising candidate since it was shown to be more cytocompatible and potent against the investigated bacteria than LL-37 in all the tested models.

11.
Toxicol In Vitro ; 63: 104714, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31706036

RESUMO

Due to the increasing need of new treatment options against bacterial lung infections, novel antimicrobial peptides (AMPs) are under development. Local bioavailability and less systemic exposure lead to the inhalation route of administration. Combining AMPs with nanocarriers (NCs) into nanosystems (NSs) might be a technique for improved results. An air-liquid interface (ALI) in vitro inhalation model was set up including a human alveolar lung cell line (A549) and an optimized exposure system (P.R.I.T.® ExpoCube®) to predict acute local lung toxicity. The approach including aerosol controls (cupper-II-sulfate and lactose) delivered lowest observable adverse effect levels (LOAELs). Different combinations of AMPs (AA139, M33) and NCs (polymeric nanoparticles (PNPs), micelles and liposomes) were tested under ALI and submerged in vitro conditions. Depending on the nature of AMP and NCs, packing of AMPs into NSs reduced the AMP-related toxicity. Large differences were found between the LOAELs determined by submerged or ALI testing with the ALI approach indicating higher sensitivity of the ALI model. Since aerosol droplet exposure is in vivo relevant, it is assumed that ALI based results represents the more significant source than submerged testing for in vivo prediction of local acute lung toxicity. In accordance with the current state-of-the-art view, this study shows that ALI in vitro inhalation models are promising tools to further develop in vitro methods in the field of inhalation toxicology.


Assuntos
Antibacterianos/toxicidade , Nanopartículas/toxicidade , Peptídeos/toxicidade , Células A549 , Aerossóis , Antibacterianos/administração & dosagem , Infecções Bacterianas/tratamento farmacológico , Sobrevivência Celular/efeitos dos fármacos , Humanos , Lipossomos , Pulmão/efeitos dos fármacos , Pneumopatias/tratamento farmacológico , Metacrilatos/administração & dosagem , Metacrilatos/toxicidade , Micelas , Nanopartículas/administração & dosagem , Nylons/toxicidade , Peptídeos/administração & dosagem
12.
Ther Drug Monit ; 31(4): 436-42, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19494792

RESUMO

There is evidence showing the importance of reaching immunosuppressant target concentrations as soon as possible. The aim of this study was to evaluate the relationship between tacrolimus trough concentrations within the first week after transplantation and the rate of acute rejection. In this descriptive-analytic study, we included 57 renal transplant patients receiving tacrolimus as the primary immunosuppressive drug. After univariate analysis, donor age, duration of hospital stay, and creatinine clearance (third month) showed significant differences between rejecters and nonrejecters. In addition, mean tacrolimus trough concentrations on day 5, day 7, mean of days 1-7, and mean of days 5-7 were found to be significantly lower in rejecters (P = 0.009, P = 0.012, P = 0.006, and P = 0.035, respectively). Receiver operating characteristic curve analysis with tacrolimus trough concentrations measured on days 5 and 7 was able to discriminate between patients with and without acute rejection (P = 0.028 and P = 0.048 after Bonferroni correction). The tacrolimus trough concentration with the best sensitivity-specificity balance was 9.3 ng/mL on day 5 and 8.7 ng/mL on day 7. In the Kaplan-Meier analysis, patients with tacrolimus trough concentrations below 9.3 mg/mL on day 5 showed a lower survival time without acute rejection (P = 0.048 after correction) in comparison with patients with tacrolimus trough concentrations above this concentration. After logistic regression, we obtained a model relating rejection with sex, donor age, and tacrolimus trough concentrations on day 5 (P = 0.004). No significant relationship between tacrolimus trough concentrations and delta creatinine clearance from week 1 to month 3 was obtained. These results confirm that tacrolimus trough concentrations during the first week are an important predictor of acute rejection. Therefore, it is critical to reach target blood concentrations of tacrolimus as soon as possible to improve allograft survival.


Assuntos
Rejeição de Enxerto , Tacrolimo/farmacologia , Rejeição de Enxerto/terapia , Humanos , Imunossupressores , Transplante de Rim , Complicações Pós-Operatórias , Tacrolimo/isolamento & purificação
13.
Am J Surg ; 217(1): 53-58, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29709273

RESUMO

BACKGROUND: The aim of this study is to assess postoperative morbidity and mortality in tumors with a proximal margin 15 cm or more from the anal verge operated with transanal endoscopic microsurgery (TEM). METHODS: This observational study of consecutive rectal tumor patients undergoing TEM was carried out from July 2004 to June 2017. We compared the results of rectal tumors at distances of ≥15 cm (group A) and <15 cm (group B) from the anal verge. RESULTS: During the study period 667 patients were included: 118 in group A and 549 in group B. In the comparative analysis there were no significant differences in morbidity (p = 0.23), mortality (p = 0.32) or free margin involvement (p = 0.545). Differences were observed in terms of lesion size (p < 0.001), surgical time (p < 0.001) and peritoneal cavity perforation, which were all increased in group A. CONCLUSION: TEM for lesions in the rectosigmoid junction is feasible and is not associated with higher morbidity or mortality.


Assuntos
Adenocarcinoma/patologia , Adenocarcinoma/cirurgia , Complicações Pós-Operatórias/epidemiologia , Neoplasias Retais/patologia , Neoplasias Retais/cirurgia , Microcirurgia Endoscópica Transanal , Adenocarcinoma/mortalidade , Idoso , Idoso de 80 Anos ou mais , Canal Anal/patologia , Estudos de Coortes , Feminino , Humanos , Masculino , Margens de Excisão , Pessoa de Meia-Idade , Duração da Cirurgia , Neoplasias Retais/mortalidade , Taxa de Sobrevida , Resultado do Tratamento
14.
J Ultrasound Med ; 27(11): 1607-15, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18946100

RESUMO

OBJECTIVE: Knowledge and quantification of the microcirculation are very important for estimating the status of an organ. Real-time contrast-enhanced sonography assesses microvascular tissue perfusion. This technique has been proposed as innocuous; however, data from experimental animals (rats) have shown renal interstitial microhemorrhage after the procedure. Therefore, we developed a porcine model to explore potential renal damage that in situ exposure might cause. METHODS: Kidneys from 8 anesthetized pigs were surgically exposed. An ultrasound contrast agent (sulfur hexafluoride) was infused through the femoral vein in a continuous perfusion. Destructive ultrasonic flashes were applied with a high mechanical index over only 1 kidney (the contralateral kidney was used as a control). Blinded histologic and laboratory analyses were performed to reveal any lesions. RESULTS: Histologic analysis of the kidney samples showed no evidence of renal damage. Biochemical parameters that could represent renal tissue damage and hemoglobin levels did not change after the microbubble-ultrasound interaction. CONCLUSIONS: The ultrasound contrast agent-ultrasound interaction in anesthetized pig kidneys under the output level for the imaging visualization and microbubble destruction used did not cause tissue damage. Our results suggest that this procedure could be used in humans for regular analysis of the kidney microcirculation with minimal risk of tissue damage.


Assuntos
Rim/citologia , Rim/diagnóstico por imagem , Modelos Animais , Sonicação , Hexafluoreto de Enxofre , Animais , Meios de Contraste , Humanos , Rim/lesões , Microbolhas , Medição de Risco/métodos , Hexafluoreto de Enxofre/efeitos adversos , Suínos , Ultrassonografia
15.
ACS Macro Lett ; 7(2): 196-200, 2018 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-35610892

RESUMO

The "pancarcinoma" Tn antigen (αGalNAc-O-Ser/Thr) is a tumor-associated carbohydrate antigen (TACA) overexpressed on the surface of cancer cells and suitable target for anticancer vaccines. However, TACAs commonly show weak immunogenicity, low in vivo stability, and poor bioavailability. To address these issues, the development of physiologically stable TACA synthetic mimetics and novel nanocarriers for multivalent display are object of intense research. Nanomaterials represent suitable scaffolds to multimerize antigens, but absence of toxicity, easy functionalization and capability to incorporate biomolecules are compulsory characteristics for vaccine nanocarriers. Here, we report on the conjugation of a synthetic Tn-antigen mimetic to biocompatible and water-dispersible dextran-based single-chain nanoparticles (DXT-SCPNs). In vitro stimulation of PBMCs and analysis of interleukins production indicated a specific innate immune modulation mediated by the multivalent presentation of the Tn mimetic at the nanoparticle surface. These preliminary results pave the way for the development of Tn-mimetic clusters on biocompatible DXT-SCPN for TACA-based vaccines.

16.
Adv Perit Dial ; 22: 33-6, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16983935

RESUMO

Patients returning to peritoneal dialysis (PD) from failed renal transplantation are recognized to be inflamed, and this situation might produce a high peritoneal solute transport status. We wanted to determine if a period of time with a kidney allograft induces a change in peritoneal function. We studied 19 PD patients who had been living with a graft for a mean of 47 +/- 39 months. We studied their peritoneal function upon starting PD (baseline), immediately before transplantation (pre-Tx), and after returning to PD when the graft failed (post-Tx). We analyzed the peritoneal mass transfer coefficients for urea (U-MTAC) and creatinine (Cr-MTAC), the dialysate-to-plasma ratio of creatinine (D/P-Cr), and net ultrafiltration (UF). We observed no significant differences in the various variables pre-Tx and post-Tx. The U-MTAC post-Tx was significantly lower than at PD baseline (25.9 +/- 8 mL/min vs. 20.2 +/- 5 mL/min, p = 0.03). The U-MTAC and Cr-MTAC post-Tx were not correlated with months on a graft or with MTAC values at baseline. In inherent high transporters (Cr-MTAC > or = 11.5 mL/min at baseline, n = 8), we observed a significant reduction in Cr-MTAC post-Tx (15.2 +/- 2 mL/min vs. 10.2 +/- 4 mL/min, p = 0.03). Three of these patients remained high transporters post-Tx. We conclude that peritoneal function upon reinitiating PD after transplantation is similar to function in the pre-transplantation phase; and that a high peritoneal transport status is more prevalent at first initiation onto PD than at return after transplantation, suggesting that inherently high transport is almost exclusively a feature of an intact, predialysis peritoneum.


Assuntos
Transplante de Rim , Diálise Peritoneal , Peritônio/metabolismo , Adulto , Transporte Biológico , Creatinina/metabolismo , Feminino , Humanos , Masculino , Ureia/metabolismo
17.
ACS Appl Mater Interfaces ; 7(7): 4433-41, 2015 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-25633414

RESUMO

A simple method to prepare multifunctional liquid marbles and dry water with magnetic, color, and fluorescent properties is presented. Multifunctional liquid marbles were prepared by encapsulation of water droplets using flocculated polymer latexes. First, the emulsion polymerization reaction of polystyrene and poly(benzyl methacrylate) was carried out using cheap and commercially available cationic surfactants. Subsequently, flocculation of the latex was provoked by an anion-exchange reaction of the cationic surfactant by the addition of lithium bis(trifluoromethanesulfonyl)imide salt. The flocculated polymer latex was filtered and dried, leading to very hydrophobic micronanoparticulated powders. These powders showed a great ability to stabilize the air/water interface. Stable liquid marbles were obtained by rolling water droplets onto the hydrophobic powders previously prepared. The use of very small polystyrene nanoparticles led us to the preparation of very stable and the biggest known liquid marbles up to 2.5 mL of water. Furthermore, the introduction of fluorescent comonomer dyes into the polymer powders allowed us to obtain new morphological images and new knowledge about the structure of liquid marbles by confocal microscopy. Furthermore, the introduction of magnetic nanoparticles into the polymer latex led to magnetic responsive liquid marbles, where the iron oxide nanoparticles are protected within a polymer. Altogether this method represents an accessible and general platform for the preparation of multifunctional liquid marbles and dry water, which may contribute to extending of their actual range of applications.

18.
Water Res ; 36(12): 3035-44, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12171402

RESUMO

Aqueous solutions of aniline and p-chloroaniline were treated with ozone in order to study the reaction and oxidation by-products. Aniline solutions were ozonated at low and high pH, so as to compare both molecular and hydroxyl free radical mechanisms, respectively. The main identified aromatic by-products were nitrobenzene and azobenzene when the experiment was carried out at acid pH. Formation of nitrobenzene, azobenzene, azoxybenzene and 2-pyridine-carboxylic was observed when the ozonation was carried out at basic pH. p-Chloroaniline was treated with ozone only at high pH and the identified by-products were in accordance with those obtained in the ozonation of aniline: p-chloronitrobenzene, 4,4'-dichloroazobenzene and 4-chloro-2-pyridine-carboxylic acid. All the aromatic by-products found were less toxic than the raw materials. The pseudo-first-order constants in aniline concentration were calculated, whilst kinetic in p-chloroaniline concentration could not be adjusted to a first-order reaction.


Assuntos
Compostos de Anilina/química , Hidrocarbonetos Aromáticos/síntese química , Ozônio/química , Água/química , Cromatografia Gasosa , Concentração de Íons de Hidrogênio , Soluções/química
19.
Dalton Trans ; 42(36): 13118-25, 2013 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-23880906

RESUMO

The preparation of Os2(TiPB)4Cl2 (1; TiPB = 2,4,6-triisopropylbenzoate) and Os2(TiPB)2(OAc)2Cl2 (2) by carboxylate exchange reactions with Os2(OAc)4Cl2 is reported. The structure of 1 has been determined by single-crystal X-ray studies, and shows a paddlewheel arrangement of the ligands about the triply bonded diosmium core. Both compounds have magnetic moments at room temperature that are consistent with the presence of two unpaired electrons, and their cyclic voltammograms show a single redox process corresponding to the Os2(5+/6+) redox couple. The electronic absorption spectra of 1 and 2 display an absorption at ~395 nm, corresponding to the π(Cl) →π*(Os2) LMCT transition, as well as numerous weaker absorptions at lower energy. Density functional theory (DFT) calculations on Os2(OAc)4Cl2 at different levels of theory (B3LYP and PBE0) have been used to probe the electronic structure of diosmium tetracarboxylates. The calculations show that these compounds have a σ(2)π(4)δ(2)δ*(1)π*(1) electronic configuration, and time-dependent DFT was used to help rationalize their optical properties.

20.
ACS Macro Lett ; 2(11): 975-979, 2013 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-35581863

RESUMO

Cholinium-based ionic liquid methacrylic monomers having halide, lactate and acetate counter-anions were synthesized and polymerized by using conventional free radical polymerization. The polymer properties were characterized by NMR, SEC/GPC, TGA, and DSC and compared among eight different cationic polymethacrylic analogs. Polycations with different methacrylic alkylammonium backbones having lactate anion displayed comparatively better thermal stability than those having the acetate counter-anions and they also exhibited lower glass transition temperatures than their counterparts having acetate and halide counteranions. As an application, cholinium lactate methacrylate ionic liquid monomer was used to prepare ion gels by photopolymerization. Interestingly, these are the first examples of ion gels which are fully composed of low toxicity and biocompatible cholinium ionic liquids. Furthermore, the same ionic liquid monomer, cholinium lactate methacrylate, showed the ability to dissolve cellulose. This facilitated the preparation of transparent poly(ionic liquid)/cellulose composite coatings by photopolymerization.

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