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1.
STAR Protoc ; 4(3): 102416, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37405928

RESUMO

Prenylation and palmitoylation are two major lipid modifications of cellular proteins that anchor proteins to cell membranes. Here, we present a protocol for detecting these modifications in cellular proteins by radioactive metabolic labeling. We describe steps for metabolic labeling of cells, cell harvesting for carrying out immunoprecipitations, subjecting immunocomplexes to SDS-PAGE, and transferring them to polyvinylidine flouride (PVDF) membranes. We then detail detection of labeled target proteins by exposing PVDF membranes to phosphor screens and using a phosphor imager machine. For complete details of this protocol, please refer to Liang et al.1.


Assuntos
Polímeros de Fluorcarboneto , Lipídeos de Membrana , Proteínas , Proteínas/metabolismo , Polivinil/metabolismo , Metabolismo dos Lipídeos
2.
Microb Ecol ; 86(1): 549-562, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35978183

RESUMO

Cell adhesion is always the first step in biofilm development. With the emergence of attached cultivation systems, this study aims to promote a cost-effective approach for sustainable cultivation of microalgae, Navicula incerta, by pre-coating the main substrates, commercial polyvinylidene fluoride (PVDF) membranes with its own washed algal cells and self-produced soluble extracellular polymeric substances (EPS) for strengthened biofilm development. The effects of pH value (6 to 9), cell suspension volume (10 to 30 mL), and EPS volume (10 to 50 mL) were statistically optimized by means of response surface methodology toolkit. Model outputs revealed good agreement with cell adhesion data variation less than 1% at optimized pre-coating conditions (7.20 pH, 30 mL cell suspension volume, and 50 mL EPS volume). Throughout long-term biofilm cultivation, results demonstrated that EPS pre-coating substantially improved the attached microalgae density by as high as 271% than pristine PVDF due to rougher surface and the presence of sticky exopolymer particles. Nutrients absorbed via the available EPS coating from the bulk medium made the immobilized cells to release less polysaccharides on an average of 30% less than uncoated PVDF. This work suggests that adhesive polymer binders derived from organic sources can be effectively integrated into the development of high-performance novel materials as biocoating for immobilized microalgae cultivation.


Assuntos
Biofilmes , Microalgas , Polivinil/metabolismo , Matriz Extracelular de Substâncias Poliméricas , Polissacarídeos/metabolismo , Microalgas/metabolismo
3.
Sci Total Environ ; 845: 157306, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-35839881

RESUMO

Anaerobic ammonia-oxidizing bacteria (AAOB) have a long growth time and low activity at low temperatures. In suspended systems, sludge is easily lost, which limits the mainstream application of anaerobic ammonia oxidation (anammox).Entrapment provides effective ideas for solving these problems. In this study, polyvinyl­sodium alginate (PVA-SA) and nano Fe2O3-PVA-SA entrapment beads were prepared to discuss the effectiveness of entrapment enhanced anammox sludge at low temperatures. The differences in the entrapped beads and granules were compared to analyze the strengthening mechanism. The results show that the nitrogen removal performance of granules, PVA-SA and nano Fe2O3-PVA-SA entrapped beads, first decreased and then increased during the cooling and low-temperature operation. Nano Fe2O3-PVA-SA entrapped beads showed the smallest decline and the highest degree of recovery. Reaction metering ratio (△NO2--N/△NH4+-N and △NO3--N/△NH4+-N) showed that entrapment could realize Nitrite oxidizing bacteria (NOB) inhibition and improve the activity of denitrifying bacteria (DNB) to promote the removal of total nitrogen by providing a strict anaerobic environment. The results demonstrate that entrapment is beneficial for maintaining the content of heme c, specifically, nano Fe2O3 can stimulate its production, and is beneficial for alleviating the reduction of hydrazine dehydrogenase (HDH) enzyme activity. The extracellular polymeric substances (EPS) content and analysis showed that entrapment does not change the composition of EPS, and can maintain the EPS content. Nano Fe2O3 can stimulate AAOB to secrete more EPS to maintain sludge stability. From a molecular perspective, entrapment can maintain the expression of functional genes, promote the enrichment of AAOB, thus improving the nitrogen removal performance from the dual perspectives of "quality" and "quantity".


Assuntos
Reatores Biológicos , Esgotos , Alginatos/metabolismo , Oxidação Anaeróbia da Amônia , Anaerobiose , Bactérias/metabolismo , Reatores Biológicos/microbiologia , Desnitrificação , Nitrogênio/metabolismo , Oxirredução , Polivinil/metabolismo , Esgotos/microbiologia , Temperatura
4.
Sci Rep ; 12(1): 2516, 2022 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-35169157

RESUMO

Clinical use of human pluripotent stem cells (hPSCs) is hampered by the technical limitations of their expansion. Here, we developed a chemically synthetic culture substrate for human pluripotent stem cell attachment and maintenance. The substrate comprises a hydrophobic polyvinyl butyral-based polymer (PVB) and a short peptide that enables easy and uniform coating of various types of cell culture ware. The coated ware exhibited thermotolerance, underwater stability and could be stored at room temperature. The substrate supported hPSC expansion in combination with most commercial culture media with an efficiency similar to that of commercial substrates. It supported not only the long-term expansion of examined iPS and ES cell lines with normal karyotypes during their undifferentiated state but also directed differentiation of three germ layers. This substrate resolves major concerns associated with currently used recombinant protein substrates and could be applied in large-scale automated manufacturing; it is suitable for affordable and stable production of clinical-grade hPSCs and hPSC-derived products.


Assuntos
Técnicas de Cultura de Células/métodos , Diferenciação Celular/efeitos dos fármacos , Autorrenovação Celular/efeitos dos fármacos , Células-Tronco Embrionárias Humanas/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Peptídeos/farmacologia , Polivinil/farmacologia , Alicerces Teciduais/química , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Células-Tronco Embrionárias Humanas/efeitos dos fármacos , Células-Tronco Embrionárias Humanas/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/metabolismo , Peptídeos/metabolismo , Polivinil/metabolismo
5.
PLoS One ; 17(1): e0262755, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35085322

RESUMO

Chronic spinal cord injury (SCI) is a highly debilitating and recalcitrant disease with limited treatment options. Although various stem cell types have shown some clinical efficacy for injury repair they have not for SCI. Hair-follicle-associated pluripotent (HAP) stem cells have been shown to differentiate into neurons, Schwan cells, beating cardiomyocytes and many other type of cells, and have effectively regenerated acute spinal cord injury in mouse models. In the present report, HAP stem cells from C57BL/6J mice, encapsulated in polyvinylidene fluoride membranes (PFM), were implanted into the severed thoracic spinal cord of C57BL/6J or athymic nude mice in the early chronic phase. After implantation, HAP stem cells differentiated to neurons, astrocytes and oligodendrocytes in the regenerated thoracic spinal cord of C57BL/6J and nude mice. Quantitative motor function analysis, with the Basso Mouse Scale for Locomotion (BMS) score, demonstrated a significant functional improvement in the HAP-stem-cell-implanted mice, compared to non-implanted mice. HAP stem cells have critical advantages over other stem cells: they do not develop teratomas; do not loose differentiation ability when cryopreserved and thus are bankable; are autologous, readily obtained from anyone; and do not require genetic manipulation. HAP stem cells therefore have greater clinical potential for SCI repair than induced pluripotent stem cells (iPSCs), neuronal stem cells (NSCs)/neural progenitor cells (NPCs) or embryonic stem cells (ESCs). The present report demonstrates future clinical potential of HAP-stem-cell repair of chronic spinal cord injury, currently a recalcitrant disease.


Assuntos
Folículo Piloso/citologia , Células-Tronco Pluripotentes Induzidas/citologia , Células-Tronco Pluripotentes/citologia , Traumatismos da Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/terapia , Regeneração da Medula Espinal/fisiologia , Animais , Diferenciação Celular/fisiologia , Polímeros de Fluorcarboneto/metabolismo , Folículo Piloso/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Nus , Camundongos Transgênicos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/fisiologia , Nestina/metabolismo , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Células-Tronco Pluripotentes/metabolismo , Polivinil/metabolismo , Medicina Regenerativa/métodos , Medula Espinal/metabolismo , Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/metabolismo
6.
ACS Appl Mater Interfaces ; 13(36): 42502-42512, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34469102

RESUMO

We report that micrometer-scale droplets of thermotropic liquid crystals (LCs) can be positioned inside living mammalian cells and deployed as chemical sensors to report the presence of toxins in extracellular environments. Our approach exploits droplets of LC enclosed in semi-permeable polymer capsules that enable internalization by cells. The LC droplets are stable in intracellular environments, but undergo optical changes upon exposure of cells to low, sub-lethal concentrations of toxic amphiphiles. Remarkably, LC droplets in intracellular environments respond to extracellular analytes that do not generate an LC response in the absence of cellular internalization. They also do not respond to other chemical stimuli or processes associated with cell growth or manipulation in culture. Our results suggest that droplet activation involves the transport and co-adsorption of amphiphilic toxins and other lipophilic cell components to the surfaces of internalized droplets. This work provides fundamentally new designs of biotic-abiotic systems that can report sensitively and selectively on the presence of select chemical agents outside cells and provides a foundation for the design of structured liquid droplets that can sense and report on other biochemical or metabolic processes inside cells.


Assuntos
Cristais Líquidos/química , Tensoativos/análise , Células 3T3 , Animais , Células HeLa , Humanos , Lactonas/química , Lactonas/metabolismo , Camundongos , Microscopia de Polarização , Microesferas , Polietilenoimina/química , Polietilenoimina/metabolismo , Polivinil/química , Polivinil/metabolismo , Dióxido de Silício/química , Dióxido de Silício/metabolismo
7.
J Biomater Appl ; 35(6): 732-739, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33331198

RESUMO

BACKGROUND: The incidence of incisional hernia is with up to 30% one of the frequent long-term complication after laparotomy. After establishing minimal invasive operations, the laparoscopic intraperitoneal onlay mesh technique (lap. IPOM) was first described in 1993. Little is known about the foreign body reaction of IPOM-meshes, which covered a defect of the parietal peritoneum. This is becoming more important, since IPOM procedure with peritoneal-sac resection and hernia port closing (IPOM plus) is more frequently used. METHODS: In 18 female minipigs, two out of three Polyvinylidene-fluoride (PVDF) -meshes (I: standard IPOM; II: IPOM with modified structure [bigger pores]; III: IPOM with the same structure as IPOM II + degradable hydrogel-coating) were placed in a laparoscopic IPOM procedure. Before mesh placement, a 2x2cm peritoneal defect was created. After 30 days, animals were euthanized, adhesions were evaluated by re-laparoscopy and mesh samples were explanted for histological and immunohistochemichal investigations. RESULTS: All animals recovered after implantation and had no complications during the follow-up period. Analysing foreign body reaction, the IPOM II mesh had a significant smaller inner granuloma, compared to the other meshes (IPOM II: 8.4 µm ± 1.3 vs. IPOM I 9.1 µm ± 1.3, p < 0.001). The degradable hydrogel coating does not prevent adhesions measured by Diamond score (p = 0.46). A peritoneal defect covered by a standard or modified IPOM mesh was a significant factor for increasing foreign body granuloma, the amount of CD3+ lymphocytes, CD68+ macrophages and decrease of pore size. CONCLUSION: A peritoneal defect covered by IPOM prostheses leads to an increased foreign body reaction compared to intact peritoneum. Whenever feasible, a peritoneal defect should be closed accurately before placing an IPOM-mesh to avoid an excessive foreign body reaction and therefore inferior biomaterial properties of the prosthesis.


Assuntos
Materiais Biocompatíveis/química , Polímeros de Fluorcarboneto/química , Reação a Corpo Estranho/etiologia , Peritônio/cirurgia , Polivinil/química , Telas Cirúrgicas/efeitos adversos , Aderências Teciduais/etiologia , Animais , Materiais Biocompatíveis/metabolismo , Feminino , Polímeros de Fluorcarboneto/metabolismo , Seguimentos , Reação a Corpo Estranho/metabolismo , Herniorrafia , Humanos , Laparoscopia , Polivinil/metabolismo , Porosidade , Complicações Pós-Operatórias , Implantação de Prótese , Propriedades de Superfície , Suínos , Porco Miniatura , Aderências Teciduais/metabolismo
8.
Eur J Pharm Biopharm ; 154: 387-396, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32717391

RESUMO

Many amorphous solid dispersions (ASDs) are thermodynamically unstable. Thus, the active pharmaceutical ingredient (API) might crystallize over time. The crystallization kinetics and therewith the long-term stability of ASDs depends on the storage conditions temperature and relative humidity (RH) as they determine the molecular mobility of the API in the polymer. To quantify the molecular mobility, the rheological behavior of two different ASDs with ibuprofen and either poly(vinyl acetate) or poly(vinylpyrrolidone-co-vinyl acetate) was analyzed as function of temperature and relative humidity by means of an oscillatory rheometer. The plasticizing effect of ibuprofen and absorbed water on the zero-shear viscosity of the polymer could be fully explained by the reduction of the glass-transition temperature of the mixture compared to the one of the pure polymer. Moreover, this work proposes an approach to predict the zero-shear viscosity of an ASD based on only the temperature dependence of the zero-shear viscosity of the pure polymer as well as the predicted water content in the ASD at certain RH using the Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT).


Assuntos
Umidade , Ibuprofeno/química , Polivinil/química , Pirrolidinas/química , Compostos de Vinila/química , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/metabolismo , Cristalização/métodos , Excipientes/química , Excipientes/metabolismo , Ibuprofeno/metabolismo , Polivinil/metabolismo , Pirrolidinas/metabolismo , Reologia/métodos , Solubilidade , Compostos de Vinila/metabolismo , Viscosidade
9.
Colloids Surf B Biointerfaces ; 191: 111025, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32305624

RESUMO

Biocatalytic removal with laccase immobilized on diverse membranes offers an attractive option to search alternative to traditional wastewater treatment processes for the removal of high toxic azo dye. In this work, the modified poly(vinylidene fluoride) membrane (PVDF) with chemical stability and high mechanical strength was developed for laccase immobilization via covalent bonding. The key design for the synthesis of biocatalytic membrane is the construction of hybrid bio-inorganic structure on the surface of polydopamine (PDA)-coated PVDF (PDA@PVDF). In this respect, the PDA layer was used as a secondary platform for the grafting of 3-triethoxysilylpropylamine (APTES) modified Fe2O3@SiO2 cubes (FS@cubes) via a solvothermal process, resulting in the formation of FS@cubes-PDA@PVDF membrane. Subsequently, laccase was immobilized on the surface of FS@ cubes-PDA@PVDF via gluteraldehyde (GA) crosslinking (Lac-FS@ cubes-PDA@PVDF). The removal efficiency of congo red by Lac-FS@cubes-PDA @PVDF reached 97.1 % under optimal reaction conditions (pH 7.0 and temperature 35 ℃), which was more efficient than free laccase. Moreover, the as-prepared Lac-FS@cubes-PDA@PVDF not only exhibited an excellent stability after low temperature storage, but also showed an outstanding reusability. Therefore, we believe that this work opens up a potential strategy for removal of other water pollutants, and provide a simple and convenient way for large-scale applications of enzyme-catalysis.


Assuntos
Corantes/isolamento & purificação , Vermelho Congo/isolamento & purificação , Lacase/química , Polivinil/química , Poluentes Químicos da Água/isolamento & purificação , Biocatálise , Corantes/química , Vermelho Congo/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Lacase/metabolismo , Tamanho da Partícula , Polivinil/metabolismo , Porosidade , Propriedades de Superfície , Poluentes Químicos da Água/química
10.
J Biomed Mater Res B Appl Biomater ; 108(5): 2250-2257, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-31967402

RESUMO

Parastomal herniation is a frequent complication in colorectal surgery, occurring with a prevalence of 30-80%. The aim of the study was to create a new intraperitoneal colostoma mesh prosthesis (IPST) with enhanced elastic properties made with thermoplastic polyurethane (TPU) monofilaments. We performed open terminal sigmoid colostomies reinforced with either a 10 cm by 10 cm polyvinylidene fluoride (PVDF) or a new TPU/PVDF composite mesh in a total of 10 minipigs. Colostoma was placed paramedian in the left lower abdomen and IPST meshes were fixed intraperitoneal. After 8 weeks, the animals were euthanized after laparoscopic exploration and specimen were explanted for histological investigations. Implantation of a new IPST-mesh with enhanced elastic properties was feasible in a minipig model within an observation period of 8 weeks. Immunohistochemically, Collagen I/III ratio as a marker of tissue integration was significantly higher in TPU-group versus PVDF group (9.4 ± 0.5 vs. 8.1 ± 0.5, p = 0.002) with a significantly lower inflammatory reaction measured by a smaller inner granuloma at mesh-colon interface (17.6 ± 3.3 µm vs. 23 ± 5 µm, p < 0.001). A new TPU/PVDF composite mesh with enhanced elastic properties as IPST was created. Stoma surgery and especially the evaluation of the new stoma mesh prosthesis are feasible with reproducible results in an animal model. Tissue integration expressed by Collagen I/III ratio seems to be improved in comparison to standard-elastic PVDF-IPST meshes.


Assuntos
Poliuretanos/metabolismo , Polivinil/metabolismo , Implantação de Prótese/métodos , Telas Cirúrgicas , Estomas Cirúrgicos/patologia , Animais , Elasticidade , Feminino , Reação a Corpo Estranho , Humanos , Inflamação/patologia , Laparoscopia , Testes Mecânicos , Poliuretanos/química , Polivinil/química , Suínos , Resistência à Tração
11.
ACS Appl Mater Interfaces ; 12(3): 3438-3444, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31877011

RESUMO

In recent years, rapid development of induced pluripotent stem cell (iPSC) technology has provided good technical support for the study of human cardiovascular disease (CVD). In this work, a mimetic cell membrane and drug carrier OPFL system containing photoactive oligo(p-phenylene vinylene) functionalized with phospholipid units (OPV-lipid) was prepared for functional regulation of iPSC-derived cardiomyocytes. OPFL bound to the cell membrane of iPSC-derived human cardiomyocytes and significantly enhanced delivery of cyclosporin A (CsA) into these cells, which promoted the regulation of mitochondrial calcium levels and membrane potential by CsA. This led to the protection of the mitochondrial structure and function, thus reducing apoptosis of iPSC-derived cardiomyocytes and achieving the effect of treating CVD. OPFL not only acts as a fluorescent probe for cell imaging and visualization of the drug delivery process but also provides a tool to deliver lipid-insoluble drugs throughout the cell membrane. Benefiting from good biocompatibility, facile operation, and a visible and controllable cell uptake process, OPFL has good potential to be a powerful tool in future basic and clinical research applications involving iPSCs.


Assuntos
Células-Tronco Pluripotentes Induzidas/citologia , Polivinil/química , Substâncias Protetoras/química , Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Membrana Celular/metabolismo , Células Cultivadas , Ciclosporina/farmacologia , Sistemas de Liberação de Medicamentos , Humanos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Células-Tronco Pluripotentes Induzidas/metabolismo , Potenciais da Membrana , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Fosfolipídeos/química , Polivinil/metabolismo
12.
Eur J Pharm Sci ; 142: 105137, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31706016

RESUMO

The aim of the current study was to prepare the efficacious amorphous solid dispersion of poorly water-soluble compound, Dolutegravir. After theoretical and experimental determination of drug-polymer miscibility, polyvinyl caprolactam-polyvinyl acetate-polyethylne glycol graft copolymer was chosen as a polymer. The solid dispersions of Dolutegravir were prepared by quench cooling and solvent evaporation method. Though quench cooling successfully stabilized the drug into amorphous form, solvent evaporation technique failed to render the drug completely amorphous. Owing to the negative Gibbs free energy at room temperature, the prepared dispersions were found stable at room temperature for 60 days. To resolve the overlapping contribution of micellar solubilization and amorphicity in improving the dissolution characteristics of Dolutegravir, the in vitro dissolution studies were performed in USP phosphate buffer as well as bio-relevant media. The dissolution advantage between prepared dispersions and pure drug in USP phosphate buffer was found bridged in the bio-relevant media. For this, the micellar solubilization driven dissolution of Dolutegravir in the presence of bile and lecithin micelles was thought as a contributing factor. Nevertheless, the dissolution advantage of dispersions prepared by quench cooling method was found endured in FeSSIF, which was thought to be due to its amorphicity leading to molecular level dissolution. Subsequently, the dissolution advantage was translated into the improved flux. Further, in vivo oral bioavailability was investigated for the dispersion prepared by quench cooling by using crystalline Dolutegravir as a control. The overall exposure of Dolutegravir was improved by 1.7 fold (AUC), while the maximum plasma concentration (Cmax) demonstrated 2 fold increase after comparing with crystalline Dolutegravir.


Assuntos
Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/metabolismo , Polietilenoglicóis/química , Polietilenoglicóis/metabolismo , Polímeros/química , Polímeros/metabolismo , Polivinil/química , Polivinil/metabolismo , Animais , Disponibilidade Biológica , Composição de Medicamentos/métodos , Masculino , Oxazinas , Transição de Fase/efeitos dos fármacos , Piperazinas , Piridonas , Ratos , Ratos Wistar , Solubilidade/efeitos dos fármacos
13.
Medicina (Kaunas) ; 55(6)2019 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-31159307

RESUMO

Selective embolization is the treatment of choice for traumatic renal pseudoaneurysm. The use of ethylene vinyl alcohol copolymer (EVOH) was recently described as an embolic agent in peripheral lesions. The aim of a good embolic agent is to: achieve rapid and effective embolization; reach and fill distal vasculature targeted for embolization; be easy to prepare and use. Moreover, it should be highly radiopaque, controllable during administration, biocompatible and cost-effective. EVOH is a non-adhesive embolic agent and its efficacy is independent from the coagulant status. The risk of non-targeted embolization should be reduced by the good radio-opacity of the embolic material that is injected under continuous fluoroscopy. Nevertheless, symptomatic EVOH migration was described. We report a unique case of embolization of a renal pseudoaneurysm and migration of EVOH in the urinary tract. Retrograde trans-urethral removal of the migrated embolic agent was successfully performed. Our case report indicates that EVOH may not be appropriate when a fistula with renal calyx is suspected, even if its migration in the urinary tract may be managed.


Assuntos
Falso Aneurisma/tratamento farmacológico , Polivinil/metabolismo , Idoso , Embolização Terapêutica/métodos , Humanos , Masculino , Polivinil/uso terapêutico , Tomografia Computadorizada por Raios X/métodos , Sistema Urinário/metabolismo , Sistema Urinário/fisiopatologia
14.
Biochem J ; 475(21): 3417-3436, 2018 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-30287490

RESUMO

Deposition of misfolded amyloid polypeptides, associated with cell death, is the hallmark of many degenerative diseases (e.g. type II diabetes mellitus and Alzheimer's disease). In vivo, cellular and extracellular spaces are occupied by a high volume fraction of macromolecules. The resulting macromolecular crowding energetically affects reactions. Amyloidogenesis can either be promoted by macromolecular crowding through the excluded volume effect or inhibited due to a viscosity increase reducing kinetics. Macromolecular crowding can be mimicked in vitro by the addition of non-specific polymers, e.g. Ficoll, dextran and polyvinyl pyrrolidone (PVP), the latter being rarely used to study amyloid systems. We investigated the effect of PVP on amyloidogenesis of full-length human islet amyloid polypeptide (involved in type II diabetes) using fibrillisation and surface activity assays, ELISA, immunoblot and microscale thermophoresis. We demonstrate that high molecular mass PVP360 promotes amyloidogenesis due to volume exclusion and increase in effective amyloidogenic monomer concentration, like other crowders, but without the confounding effects of viscosity and surface activity. Interestingly, we also show that low molecular mass PVP10 has unique inhibitory properties as inhibition of fibril elongation occurs mainly in the bulk solution and is due to PVP10 directly and strongly interacting with amyloid species rather than the increase in viscosity typically associated with macromolecular crowding. In vivo, amyloidogenesis might be affected by the properties and proximity of endogenous macromolecular crowders, which could contribute to changes in associated pathogenesis. More generally, the PVP10 molecular backbone could be used to design small compounds as potential inhibitors of toxic species formation.


Assuntos
Amiloide/química , Substâncias Macromoleculares/química , Polímeros/química , Polivinil/química , Pirrolidinonas/química , Doença de Alzheimer/metabolismo , Amiloide/metabolismo , Amiloidose/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Cinética , Substâncias Macromoleculares/metabolismo , Polímeros/metabolismo , Polivinil/metabolismo , Pirrolidinonas/metabolismo , Viscosidade
15.
Chemistry ; 24(11): 2584-2587, 2018 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-29315897

RESUMO

To date, many poly(ethylene glycol) (PEG) and poly(N-isopropylacrylamide) (PNIPAAm) biomolecule conjugates have been described, but they often show long response times, are not bio-inert, or lose function in biological fluids. Herein, we present a modular synthetic approach to generate polyvinylphosphonate biomolecule conjugates. These conjugates exhibit a sharp phase transition temperature even under physiological conditions where few other examples with this property have been described to date. Furthermore, it was feasible to add biological functions to the polymers via the conjugation step. The polyvinylphosphonate cholesterol constructs are attached to the cellular membrane and the folic acid anchored polymers are shuttled into the cells. This is an exceptional finding through a straightforward synthetic approach.


Assuntos
Corantes Fluorescentes/química , Polivinil/química , Linhagem Celular , Corantes Fluorescentes/metabolismo , Ácido Fólico/química , Humanos , Microscopia Confocal , Ácidos Fosforosos/química , Polivinil/metabolismo , Espectrofotometria
16.
Biotechnol Appl Biochem ; 65(3): 362-371, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29222863

RESUMO

In recent years, the application of carbonic anhydrase (CA) in CO2 removal has attracted great interest. However, obtaining high enzyme recovery activity is difficult in existing immobilization techniques. In this work, water plasma-treated poly(vinylidene fluoride) (PVDF) membranes were modified via 3-aminopropyl triethoxy silane (KH550) or γ-(2, 3-epoxypropoxy) propyl trimethoxy silane (KH560), and then CA was attached. The immobilization process was optimized, and the catalytic properties of PVDF-attached CA were characterized. The maximum activity recovery of PVDF-KH550-CA was 60%, whereas that of PVDF-KH560-CA was 33%. The Km values of PVDF-KH550-CA, PVDF-KH560-CA, and free enzyme were 9.97 ± 0.37, 12.5 ± 0.2, and 6.18 ± 0.23 mM, respectively, and their Kcat /Km values were 206 ± 2, 117 ± 5, and 488 ± 4 M-1 ·Sec-1 . PVDF-attached CA shows excellent storage stability and reusability, and their half-life values were 82 and 78 days at 4 °C. At 25 °C, they were 50 and 37 days, respectively. PVDF-KH550-CA and PVDF-KH560-CA retained approximately 85% and 72% of the initial activity after undergoing 10 cycles. In the presence of them, the generation rates of CaCO3 were 76% and 65% of the free CA system, which were 1.6 and 1.3 times that of the blank system, respectively. Its role in accelerating CO2 sequestration holds great promise for its practical application.


Assuntos
Anidrases Carbônicas/metabolismo , Enzimas Imobilizadas/metabolismo , Polivinil/metabolismo , Estrutura Molecular , Polivinil/química
17.
J Stroke Cerebrovasc Dis ; 26(4): e62-e63, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28161148

RESUMO

The Cognard type V dural arteriovenous fistula (dAVF), which has a drainage route into the spinal vein, is a rare subtype of cranial dAVF. Because of typical features such as progressive myelopathy and brainstem dysfunctions, aggressive treatments should be considered. To eliminate venous congestion of the spinal cord, various approaches including surgical interruption of the spinal draining vein or transarterial embolization with cyanoacrylate have been reported. The introduction of nonadhesive Onyx has changed the treatment of dAVF, although little is known about the clinical usefulness of this type of fistula. We describe a case of the Cognard type V dAVF, draining into the spinal vein through the occipital sinus (OS) successfully treated by transarterial double catheter injection of Onyx. We used the alternating injections from 2 microcatheters until the Onyx reached the OS and reflowed into feeders adequately. This technique contributed to the elimination of the remaining afferent flow in an early stage of Onyx injection and achieved enough penetration into the draining vein.


Assuntos
Seio Cavernoso/patologia , Malformações Vasculares do Sistema Nervoso Central/cirurgia , Seio Cavernoso/diagnóstico por imagem , Malformações Vasculares do Sistema Nervoso Central/diagnóstico por imagem , Angiografia Cerebral , Dimetil Sulfóxido/metabolismo , Embolização Terapêutica/métodos , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Polivinil/metabolismo
18.
ACS Nano ; 11(3): 2494-2508, 2017 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-28107625

RESUMO

Mild heat stimulation of muscle cells within the physiological range represents an intriguing approach for the modulation of their functions. In this work, photothermal conversion was exploited to remotely stimulate striated muscle cells by using gold nanoshells (NSs) in combination with near-infrared (NIR) radiation. Temperature increments of approximately 5 °C were recorded by using an intracellular fluorescent molecular thermometer and were demonstrated to efficiently induce myotube contraction. The mechanism at the base of this phenomenon was thoroughly investigated and was observed to be a Ca2+-independent event directly involving actin-myosin interactions. Finally, chronic remote photothermal stimulations significantly increased the mRNA transcription of genes encoding heat shock proteins and sirtuin 1, a protein which in turn can induce mitochondrial biogenesis. Overall, we provide evidence that remote NIR + NS muscle excitation represents an effective wireless stimulation technique with great potential in the fields of muscle tissue engineering, regenerative medicine, and bionics.


Assuntos
Ouro/química , Fibras Musculares Esqueléticas/metabolismo , Nanoconchas/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/metabolismo , Diferenciação Celular , Linhagem Celular , Ouro/metabolismo , Camundongos , Fibras Musculares Esqueléticas/química , Fibras Musculares Esqueléticas/citologia , Polivinil/química , Polivinil/metabolismo , Pirrolidinas/química , Pirrolidinas/metabolismo , Dióxido de Silício/química , Dióxido de Silício/metabolismo
19.
Biotechnol Appl Biochem ; 64(6): 803-809, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27696534

RESUMO

An extracellular esterase gene estK was identified in Pseudomonas putida mt-2 and overexpressed at high levels in Escherichia coli. The recombinant EstK enzyme was purified and characterized kinetically against p-nitrophenyl ester and other aryl-alkyl ester substrates and found to be selective for hydrolysis of acetyl ester substrates with high activity for p-nitrophenyl acetate (kcat 5.5 Sec-1 , KM 285 µM). Recombinant EstK was found to catalyze deacetylation of acetylated beech xylan, indicating a possible in vivo function for this enzyme, and partial deacetylation of a synthetic polymer (poly(vinylacetate)). EstK was found to catalyze enantioselective hydrolysis of racemic 1-phenylethyl acetate, generating 1R-phenylethanol with an enantiomeric excess of 80.4%.


Assuntos
Esterases/metabolismo , Polivinil/metabolismo , Pseudomonas putida/enzimologia , Xilanos/metabolismo , Acetilação , Biocatálise , Esterases/química , Esterases/isolamento & purificação , Hidrólise , Cinética , Estrutura Molecular , Polivinil/química , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Estereoisomerismo , Xilanos/química
20.
Eur J Pharm Sci ; 97: 55-61, 2017 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-27810562

RESUMO

The present study was aimed to evaluate the applicability of a self-micellizing solid dispersion (SMSD) system of itraconazole (ITZ) with the use of Soluplus® to achieve improved dissolution and stable oral absorption of ITZ under hypochlorhydric conditions. The SMSD of ITZ (SMSD/ITZ) was prepared by the freeze-drying method. Physicochemical properties of SMSD/ITZ were assessed in terms of morphology, crystallinity, particle size, thermal behavior, dissolution profile, and stability. The pharmacokinetic profile of SMSD/ITZ was evaluated in both normal rats and omeprazole-treated rats as a hypochlorhydric model. From the crystallinity assessment, ITZ in SMSD/ITZ might exist in an amorphous state. The dissolution behavior of SMSD/ITZ was markedly improved under both acidic and neutral conditions through the formation of nano-micelles with a diameter of 127nm. The degradation of ITZ in SMSD/ITZ was negligible after storage under accelerated conditions at 40°C or 40°C/75%RH for 4weeks. Under light exposure, ca. 33% of ITZ in SMSD/ITZ was degraded, suggesting the need for protection from light. Although the oral absorption of crystalline ITZ was negligible, SMSD/ITZ showed an improved pharmacokinetic profile in normal rats, with an absolute bioavailability (BA) of 2.9%, and even 6.3% in the hypochlorhydric model. From these findings, SMSD technology could be beneficial for improving the absorption profiles of weak basic drugs, even in hypochlorhydric patients.


Assuntos
Acloridria/metabolismo , Antifúngicos/metabolismo , Absorção Intestinal/fisiologia , Itraconazol/metabolismo , Micelas , Polietilenoglicóis/metabolismo , Polivinil/metabolismo , Acloridria/tratamento farmacológico , Administração Oral , Animais , Antifúngicos/administração & dosagem , Antifúngicos/química , Linhagem Celular , Liberação Controlada de Fármacos/efeitos dos fármacos , Liberação Controlada de Fármacos/fisiologia , Absorção Intestinal/efeitos dos fármacos , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Itraconazol/administração & dosagem , Itraconazol/química , Masculino , Polietilenoglicóis/administração & dosagem , Polietilenoglicóis/química , Polivinil/administração & dosagem , Polivinil/química , Ratos , Ratos Sprague-Dawley , Difração de Raios X
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