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1.
Gut ; 71(12): 2430-2438, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35760493

RESUMO

OBJECTIVE: Irritable bowel syndrome with diarrhoea (IBS-D) is a common and challenging condition that significantly reduces quality of life. Enterosgel (polymethylsiloxane polyhydrate) is an intestinal adsorbent which sequesters harmful molecules and is safe and effective in acute infective diarrhoea. This randomised controlled multicentre trial aimed to investigate its safety and efficacy in patients with IBS-D. DESIGN: After a 2-week screening phase, participants were randomised into an 8-week double-blind phase, followed by an 8-week open-label and follow-up phase. Participants recorded stool consistency, pain and global symptoms in e-diaries and questionnaires. The primary outcome was the percentage of responders on a composite abdominal pain (≥30% decrease in the weekly score) and stool consistency (50% reduction in days per week with at least one stool of BSFS type 6 or 7) score during at least 4 weeks of the treatment period. RESULTS: 440 patients with IBS-D were randomised to the double-blind phase with 393 continuing to the open-label phase. The Primary outcome responder rate by intention-to-treat for enterosgel versus placebo was 37.4% vs 24.3% (OR 1.95, NNT 8, p=0.002). Enterosgel also improved stool consistency (48.5% vs 32.5%, p<0.0001) abdominal pain (53.3% vs 40.2%, p=0.003), stool frequency (treatment effect -0.32 (-0.62 to -0.02)) and urgency (treatment effect -0.59 (-0.85 to -0.33)). 60% of patients reported adequate relief of symptoms after open-label treatment. Adverse event frequency was similar in both groups, with no serious events attributable to enterosgel. CONCLUSION: Enterosgel is safe and effective in IBS-D, providing an alternative to the limited current treatment options. TRIAL REGISTRATION NUMBER: ISRCTN17149988.


Assuntos
Síndrome do Intestino Irritável , Humanos , Síndrome do Intestino Irritável/complicações , Síndrome do Intestino Irritável/tratamento farmacológico , Síndrome do Intestino Irritável/diagnóstico , Qualidade de Vida , Resultado do Tratamento , Diarreia/tratamento farmacológico , Diarreia/etiologia , Diarreia/diagnóstico , Dor Abdominal/tratamento farmacológico , Dor Abdominal/etiologia , Método Duplo-Cego
2.
Mater Sci Eng C Mater Biol Appl ; 121: 111859, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33579491

RESUMO

In this study, we developed a method to prepare inorganic nanoparticles in situ on the surface of cationized cellulose using a rapid microwave-assisted synthesis. Selenium nanoparticles (SeNPs) were employed as a novel type of antimicrobial agent and, using the same method, silver nanoparticles (AgNPs) were also prepared. The results demonstrated that both SeNPs and AgNPs of about 100 nm in size were generated on the cationized cellulose fabrics. The antibacterial tests revealed that the presence of SeNPs clearly improved the antibacterial performance of cationized cellulose in a similar way as AgNPs. The functionalised fabrics demonstrated strong antibacterial activity when assessed using the challenge test method, even after repeated washing. Microscopic investigations revealed that the bacterial cells were visually damaged through contact with the functionalised fabrics. Furthermore, the functionalised fabrics showed low cytotoxicity towards human cells when tested in vitro using an indirect contact method. In conclusion, this study provides a new approach to prepare cationic cellulose fabrics functionalised with Se or Ag nanoparticles, which exhibit excellent antimicrobial performance, low cytotoxicity and good laundry durability. We have demonstrated that SeNPs can be a good alternative to AgNPs and the functionalised fabrics have great potential to serve as an anti-infective material.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Selênio , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Celulose , Humanos , Testes de Sensibilidade Microbiana , Prata
3.
Trials ; 21(1): 122, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32000822

RESUMO

BACKGROUND: Irritable bowel syndrome (IBS) with diarrhoea (IBS-D) is a common and chronic condition that can significantly impair quality of life. The emergence of new drugs for IBS-D has been slow and there is a need for new treatments, including drug-free treatments, which are easy to use and suitable for different patient groups. Currently available drug-free treatments include Enterosgel®, an intestinal adsorbent approved for use in IBS-D and acute diarrhoea and available over-the-counter in the UK and 30 countries worldwide. The aim of this randomised, double-blind, placebo-controlled, multi-centre study is to test the efficacy and safety of Enterosgel® compared to placebo in symptomatic treatment in IBS-D. METHODS/DESIGN: We will recruit 430 participants with IBS-D from approximately 30 primary and secondary care sites in England. Participants meeting the required abdominal pain and stool consistency criteria over a 2-week screening period will be randomly allocated to receive blinded treatment (Enterosgel® or placebo) for 8 weeks. This will be followed by an 8-week open-label treatment phase with Enterosgel®. Participants will be allowed to adjust their daily dosage during both phases based on their symptoms. Participants will then return to standard care and those who responded to treatment will receive a follow-up call 8 weeks later. Co-medication with loperamide will be permitted and use recorded. The primary outcome measure is the percentage of participants defined as responders for abdominal pain and stool consistency during at least 4 weeks in the 8-week blinded phase. Secondary outcome measures include stool frequency, stool consistency, abdominal pain, bloating, urgency, adequate relief, questionnaire scores and rescue medication use. Exploratory outcomes will be assessed in subsets of participants including qualitative and quantitative data on faecal microorganisms and biomarkers and gut-related measurements from magnetic resonance imaging data. DISCUSSION: This is the first large scale randomised controlled trial investigating Enterosgel® in IBS-D. A study design with blinded phase followed by an open-label phase was chosen to encourage participation and study completion. Demonstrating that Enterosgel® is effective and safe in IBS-D could encourage adoption by patients and healthcare professionals and foster future clinical trials assessing its use in related conditions. TRIAL REGISTRATION: ISRCTN17149988. Prospectively registered on 14 November 2017.


Assuntos
Dor Abdominal , Diarreia , Absorção Intestinal/efeitos dos fármacos , Síndrome do Intestino Irritável , Silicones , Dor Abdominal/tratamento farmacológico , Dor Abdominal/etiologia , Adulto , Diarreia/etiologia , Diarreia/terapia , Método Duplo-Cego , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/efeitos adversos , Feminino , Fármacos Gastrointestinais/administração & dosagem , Fármacos Gastrointestinais/efeitos adversos , Humanos , Síndrome do Intestino Irritável/fisiopatologia , Síndrome do Intestino Irritável/terapia , Masculino , Estudos Multicêntricos como Assunto , Avaliação de Resultados em Cuidados de Saúde , Ensaios Clínicos Controlados Aleatórios como Assunto , Silicones/administração & dosagem , Silicones/efeitos adversos , Desintoxicação por Sorção/métodos , Inquéritos e Questionários
4.
BMJ Open Gastroenterol ; 6(1): e000287, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31139427

RESUMO

BACKGROUND: Acute intestinal infections are common conditions causing high morbidity and mortality especially in the young and elderly, resulting in a significant burden on health service resources and the economy. Current National Institute for Health and Care Excellence guidance are fluid and nutritional management; however, this does not reduce the duration of diarrhoea and the challenge of treating diarrhoea itself remains. We investigated the efficacy, tolerability and safety of intestinal adsorbent Enterosgel (polymethylsiloxane polyhydrate) compared with standard care in adults with acute diarrhoea. METHODS: This was a randomised controlled trial enrolling 105 subjects to receive the medical device Enterosgel up to six times daily for up to 8 days with standard care (oral rehydration solution), or standard care alone. The primary endpoint was the duration of diarrhoea (hours) from randomisation to first non-loose stool in the Enterosgel versus control group. RESULTS: A total of 51 subjects were randomised into the Enterosgel group and 54 into the control group, after excluding missing data, the data from 43 subjects in each group were analysed. Duration of diarrhoea was significantly shorter in the Enterosgel group at 27 hours versus 39 hours in the control group (HR was 1.74 [95% CI 1.06 to 2.87]) (p=0.03). This yielded a number needed to treat value of 5. Enterosgel was well tolerated and safe with no serious adverse events. One serious diarrhoea-related event resulting in hospitalisation was reported in the control group. CONCLUSIONS: Enterosgel treatment was associated with a significant reduction in the duration of diarrhoea in adults with patient-reported acute diarrhoea, compared with standard care. These findings support the role of Enterosgel in acute diarrhoea especially in vulnerable groups where rapid resolution of symptoms is required. Reduction in symptom duration could translate to less healthcare costs and socioeconomic burden. TRIAL REGISTRATION NUMBER: ISRCTN20758708.

5.
Sci Rep ; 9(1): 5629, 2019 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-30948767

RESUMO

Oral intestinal adsorbents (enterosorbents) are orally administered materials which pass through the gut where they bind (adsorb) various substances. The enterosorbent Enterosgel (Polymethylsiloxane polyhdrate) is recommended as a symptomatic treatment for acute diarrhoea and chronic diarrhoea associated with irritable bowel syndrome (IBS). Since 1980's there have been many Enterosgel clinical trials, however, the detailed mechanism of Enterosgel action towards specific toxins and interaction with concomitantly administered medications has not been fully investigated. Our in vitro study assessed the adsorption capacity of Enterosgel for bacterial enterotoxins and endotoxin, bile acids and interaction with the pharmaceutical drugs; Cetirizine and Amitriptyline hydrochloride. Our data demonstrate the good adsorption capacity of Enterosgel for bacterial toxins associated with gastrointestinal infection, with a lower than the comparator charcoal Charcodote capacity for bile acids whose levels can be raised in IBS patients. Adsorption capacity for the two drugs varied but was significantly lower than Charcodote. These findings suggest that the mechanism of Enterosgel action in the treatment of gastrointestinal infection or IBS is adsorption of target molecules followed by removal from the body. This therapy offers a drug free approach to prevention and treatment of infectious and chronic non-infectious diseases, where intestinal flora and endotoxemia play a role.


Assuntos
Enteroadsorção/métodos , Silicones/química , Silicones/farmacologia , Adsorção , Amitriptilina/metabolismo , Toxinas Bacterianas/metabolismo , Ácidos e Sais Biliares/metabolismo , Cetirizina/metabolismo , Carvão Vegetal , Diarreia/tratamento farmacológico , Gastroenteropatias/tratamento farmacológico , Microbioma Gastrointestinal/efeitos dos fármacos , Síndrome do Intestino Irritável/tratamento farmacológico
6.
Sci Total Environ ; 630: 1237-1245, 2018 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-29554745

RESUMO

Development of porous carbons with high specific surface area (>1200mg-1) targeted at nitrate removal from aqueous solutions is investigated by chemical activation of carbonized rice husk. Potassium carbonate is used as activating and desilicating agent. The effect of post-synthetic treatment by gas phase ammoxidation with ozone/ammonia or oxidation with concentrated nitric acid followed by nitrification with urea on main physicochemical properties and on the effectiveness of the activated carbons in nitrate removal is compared with those determined for a pristine activated carbonized rice husk sample. The two-fold enhancement of nitrate removal by the urea-modified activated carbon in comparison with pristine and ammoxidated sample is in direct correlation with the development of surface basic groups.


Assuntos
Carvão Vegetal/química , Nitratos/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Nitratos/análise , Oryza/química , Poluentes Químicos da Água/análise
7.
Biomed Mater ; 12(3): 035001, 2017 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-28270638

RESUMO

Nanoporous adsorbents are promising materials to augment the efficacy of haemodialysis for the treatment of end stage renal disease where mortality rates remain unacceptably high despite improvements in membrane technology. Complications are linked in part to inefficient removal of protein bound and high molecular weight uraemic toxins including key marker molecules albumin bound indoxyl sulphate (IS) and p-cresyl sulphate (PCS) and large inflammatory cytokines such as IL-6. The following study describes the assessment of a nanoporous activated carbon monolith produced using a novel binder synthesis route for scale up as an in line device to augment haemodialysis through adsorption of these toxins. Small and large monoliths were synthesised using an optimised ratio of lignin binder to porous resin of 1 in 4. Small monoliths showing combined significant IS, p-CS and IL-6 adsorption were used to measure haemocompatibility in an ex vivo healthy donor blood perfusion model, assessing coagulation, platelet, granulocyte, T cells and complement activation, haemolysis, adsorption of electrolytes and plasma proteins. The small monoliths were tested in a naive rat model and showed stable blood gas values, blood pressure, blood biochemistry and the absence of coagulopathies. These monoliths were scaled up to a clinically relevant size and were able to maintain adsorption of protein bound uraemic toxins IS, PCS and high molecular weight cytokines TNF-α and IL-6 over 240 min using a flow rate of 300 ml min-1 without platelet activation. The nanoporous monoliths where haemocompatible and retained adsorptive efficacy on scale up with negligible pressure drop across the system indicating potential for use as an in-line device to improve haemodialysis efficacy by adsorption of otherwise poorly removed uraemic toxins.


Assuntos
Resinas Acrílicas/química , Remoção de Componentes Sanguíneos/instrumentação , Lignina/química , Nanopartículas/química , Diálise Renal/instrumentação , Ultrafiltração/métodos , Uremia/sangue , Absorção Fisico-Química , Adsorção , Remoção de Componentes Sanguíneos/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Teste de Materiais , Nanopartículas/ultraestrutura , Nanoporos/ultraestrutura , Diálise Renal/métodos , Ultrafiltração/instrumentação , Uremia/prevenção & controle
8.
Biomaterials ; 50: 140-53, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25736504

RESUMO

Polymeric cryogels are efficient carriers for the immobilization of biomolecules because of their unique macroporous structure, permeability, mechanical stability and different surface chemical functionalities. The aim of the study was to demonstrate the potential use of macroporous monolithic cryogels for biotoxin removal using anthrax toxin protective antigen (PA), the central cell-binding component of the anthrax exotoxins, and covalent immobilization of monoclonal antibodies. The affinity ligand (protein A) was chemically coupled to the reactive hydroxyl and epoxy-derivatized monolithic cryogels and the binding efficiencies of protein A, monoclonal antibodies to the cryogel column were determined. Our results show differences in the binding capacity of protein A as well as monoclonal antibodies to the cryogel adsorbents caused by ligand concentrations, physical properties and morphology of surface matrices. The cytotoxicity potential of the cryogels was determined by an in vitro viability assay using V79 lung fibroblast as a model cell and the results reveal that the cryogels are non-cytotoxic. Finally, the adsorptive capacities of PA from phosphate buffered saline (PBS) were evaluated towards a non-glycosylated, plant-derived human monoclonal antibody (PANG) and a glycosylated human monoclonal antibody (Valortim(®)), both of which were covalently attached via protein A immobilization. Optimal binding capacities of 108 and 117 mg/g of antibody to the adsorbent were observed for PANG attached poly(acrylamide-allyl glycidyl ether) [poly(AAm-AGE)] and Valortim(®) attached poly(AAm-AGE) cryogels, respectively, This indicated that glycosylation status of Valortim(®) antibody could significantly increase (8%) its binding capacity relative to the PANG antibody on poly(AAm-AGE)-protien-A column (p < 0.05). The amounts of PA which remained in the solution after passing PA spiked PBS through PANG or Valortim bound poly(AAm-AGE) cryogel were significantly (p < 0.05) decreased relative to the amount of PA remained in the solution after passing through unmodified as well as protein A modified poly(AAm-AGE) cryogel columns, indicates efficient PA removal from spiked PBS over 60 min of circulation. The high adsorption capacity towards anthrax toxin PA of the cryogel adsorbents indicated potential application of these materials for treatment of Bacillus anthracis infection.


Assuntos
Anticorpos Monoclonais/metabolismo , Antígenos de Bactérias/isolamento & purificação , Toxinas Bacterianas/isolamento & purificação , Criogéis , Proteínas Imobilizadas/metabolismo , Proteína Estafilocócica A/metabolismo , Resinas Acrílicas/química , Adsorção , Animais , Soluções Tampão , Morte Celular , Linhagem Celular , Sobrevivência Celular , Cricetinae , Criogéis/metabolismo , Humanos , Fenômenos Mecânicos , Microscopia Confocal , Porosidade , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
9.
J Mater Sci Mater Med ; 25(6): 1589-97, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24573455

RESUMO

Adsorbents designed with porosity which allows the removal of protein bound and high molecular weight uraemic toxins may improve the effectiveness of haemodialysis treatment of chronic kidney disease (CKD). A nanoporous activated carbon monolith prototype designed for direct blood contact was first assessed for its capacity to remove albumin bound marker toxins indoxyl sulphate (IS), p-cresyl sulphate (p-CS) and high molecular weight cytokine interleukin-6 in spiked healthy donor studies. Haemodialysis patient blood samples were then used to measure the presence of these markers in pre- and post-dialysis blood and their removal by adsorbent recirculation of post-dialysis blood samples. Nanopores (20-100 nm) were necessary for marker uraemic toxin removal during in vitro studies. Limited removal of IS and p-CS occurred during haemodialysis, whereas almost complete removal occurred following perfusion through the carbon monoliths suggesting a key role for such adsorbent therapies in CKD patient care.


Assuntos
Carvão Vegetal/química , Cresóis/isolamento & purificação , Hemofiltração/instrumentação , Indicã/isolamento & purificação , Interleucina-6/isolamento & purificação , Diálise Renal/instrumentação , Ésteres do Ácido Sulfúrico/isolamento & purificação , Uremia/sangue , Absorção , Cresóis/sangue , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Indicã/sangue , Interleucina-6/sangue , Teste de Materiais , Membranas Artificiais , Projetos Piloto , Ésteres do Ácido Sulfúrico/sangue , Uremia/prevenção & controle
10.
Int J Artif Organs ; 36(9): 624-32, 2013 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-23918264

RESUMO

The aim of the present study was to develop and investigate nanoporous activated carbon materials for their ability to adsorb inflammatory cytokines directly from blood, for a range of therapeutic applications, including: systemic inflammatory response syndrome (SIRS) related to sepsis, cardio-pulmonary by-pass surgery, or ischemic reperfusion injury. Building on the previously established relationship between the porous structure of beaded polymer-derived activated carbon and its capacity to adsorb inflammatory molecules, we have developed and characterized monolithic porous carbon columns produced from the same polymer precursor matrix as carbon microbeads. The monolithic columns developed were assessed for their ability to adsorb inflammatory molecules from blood in a circulating system. Preliminary findings demonstrated good removal of the inflammatory cytokines IL-8 (100% removal), IL-6 (80% removal), and TNF (51% removal) from blood. The efficiency of cleansing is dependent on the size of the adsorbed molecule and the porous structure of the monolith, highlighting their potential for use as a hemoadsorption device.


Assuntos
Citocinas/sangue , Sepse/terapia , Adsorção , Carbono/química , Circulação Extracorpórea , Humanos , Interleucina-6/sangue , Interleucina-8/sangue , Microesferas , Porosidade , Sepse/sangue , Fator de Necrose Tumoral alfa/sangue
11.
J Mater Sci Mater Med ; 24(5): 1217-27, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23386212

RESUMO

Bio-active glass has been developed for use as a bone substitute with strong osteo-inductive capacity and the ability to form strong bonds with soft and hard tissue. The ability of this material to enhance tissue in-growth suggests its potential use as a substitute for the dental laminate of an osteo-odonto-keratoprosthesis. A preliminary in vitro investigation of porous bio-active glass as an OOKP skirt material was carried out. Porous glass structures were manufactured from bio-active glasses 1-98 and 28-04 containing varying oxide formulation (1-98, 28-04) and particle size range (250-315 µm for 1-98 and 28-04a, 315-500 µm for 28-04b). Dissolution of the porous glass structure and its effect on pH was measured. Structural 2D and 3D analysis of porous structures were performed. Cell culture experiments were carried out to study keratocyte adhesion and the inflammatory response induced by the porous glass materials. The dissolution results suggested that the porous structure made out of 1-98 dissolves faster than the structures made from glass 28-04. pH experiments showed that the dissolution of the porous glass increased the pH of the surrounding solution. The cell culture results showed that keratocytes adhered onto the surface of each of the porous glass structures, but cell adhesion and spreading was greatest for the 98a bio-glass. Cytokine production by all porous glass samples was similar to that of the negative control indicating that the glasses do not induce a cytokine driven inflammatory response. Cell culture results support the potential use of synthetic porous bio-glass as an OOKP skirt material in terms of limited inflammatory potential and capacity to induce and support tissue ingrowth.


Assuntos
Substitutos Ósseos/química , Cerâmica/química , Transplante de Córnea/instrumentação , Próteses e Implantes , Alicerces Teciduais/química , Substitutos Ósseos/farmacologia , Adesão Celular/efeitos dos fármacos , Técnicas de Cultura de Células/instrumentação , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Cerâmica/farmacologia , Ceratócitos da Córnea/citologia , Ceratócitos da Córnea/metabolismo , Ceratócitos da Córnea/fisiologia , Citocinas/metabolismo , Humanos , Teste de Materiais , Porosidade
13.
ACS Appl Mater Interfaces ; 4(11): 5936-44, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23088424

RESUMO

A set of glutaraldehyde (GA) cross-linked poly(vinyl alcohol)/activated carbon (PVA/GA/AC) composites prepared in the form of monolithic rods using a cryogelation technique and studied using adsorption, mercury porosimetry, scanning electron microscopy (SEM), and quantum chemistry methods display porosity similar to that of PVA/GA cryogel at a high GA content (content ratio GA/AC = 1 and GA/PVA = 0.2). GA cross-linked PVA multilayer coverage is an effective barrier for adsorption on AC particles. Variations in surface chemistry (AC initial and oxidized in air at 300 °C for 12 h) and content (14-62.5%w/w) of ACs in PVA/GA/AC composites relatively weakly affect their textural characteristics at a high GA content (specific surface area S(BET) < 120 m²/g, pore volume V(p) < 0.35 cm³/g). However, PVA/GA/AC composite rods formed with a lower concentration of GA (content ratio GA/AC = 1/6 and GA/PVA = 1/10) have significantly greater S(BET) (∼500 m²/g) and V(p) (>0.55 cm³/g) values because of improved accessibility of the AC surface. This provides better adsorption of methylene blue as a probe compound.


Assuntos
Carvão Vegetal/química , Azul de Metileno/isolamento & purificação , Álcool de Polivinil/química , Ultrafiltração/métodos , Absorção , Teste de Materiais , Azul de Metileno/química , Microesferas , Tamanho da Partícula , Propriedades de Superfície
14.
J Pediatr Nurs ; 26(5): 446-55, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21930031

RESUMO

Among adults, trait anger, patterns of anger expression, and stress have been associated with blood pressure (BP). Less apparent is the effect of these variables on BP in overweight and obese children. To characterize the relationships between these psychological variables and BP, the authors conducted a secondary analysis of data from 73 overweight and obese 9- to 11-year-old children. Findings indicate a positive correlation between trait anger and systolic BP (SBP). Regression results indicate that the overall model significantly predicted SBP by explaining 15.4% of the variance and that trait anger was a significant predictor of SBP.


Assuntos
Ira/fisiologia , Pressão Sanguínea/fisiologia , Emoções Manifestas/fisiologia , Sobrepeso/fisiopatologia , Estresse Psicológico/fisiopatologia , Criança , Feminino , Humanos , Masculino , Obesidade/fisiopatologia , Análise de Regressão
15.
Biomacromolecules ; 12(10): 3733-40, 2011 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-21842874

RESUMO

In the course of severe pathological conditions, such as acute liver failure and sepsis, toxic metabolites and mediators of inflammation are released into the patient's circulation. One option for the supportive treatment of these conditions is plasmapheresis, in which plasma, after being separated from the cellular components of the blood, is cleansed by adsorption of harmful molecules on polymers or activated carbon. In this work, the adsorption characteristics of activated carbon beads with levels of activation ranging from 0 to 86% were assessed for both hydrophobic compounds accumulating in liver failure (bilirubin, cholic acid, phenol and tryptophan) and cytokines (tumor necrosis factor α and interleukin-6). Progressive activation resulted in significant gradual reduction of both bulk density and mean particle size, in an increase in the specific surface area, and to changes in pore size distribution with progressive broadening of micropores. These structural changes went hand in hand with enhanced adsorption of small adsorbates, such as IL-6 and cholic acid and, to a lesser extent, also of large molecules, such as TNF-α.


Assuntos
Inflamação/terapia , Falência Hepática Aguda/terapia , Plasmaferese/métodos , Adsorção , Bilirrubina/sangue , Carbono/química , Colatos/sangue , Humanos , Inflamação/sangue , Inflamação/complicações , Inflamação/fisiopatologia , Interleucina-6/sangue , Falência Hepática Aguda/sangue , Falência Hepática Aguda/complicações , Falência Hepática Aguda/fisiopatologia , Tamanho da Partícula , Fenol/sangue , Porosidade , Triptofano/sangue , Fator de Necrose Tumoral alfa/sangue
16.
J Colloid Interface Sci ; 358(2): 582-92, 2011 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-21457992

RESUMO

The textural and adsorption characteristics of a series of activated carbons (ACs), porous poly(vinyl alcohol) (PVA) gels, and PVA/AC composites were studied using scanning electron microscopy, mercury porosimetry, adsorption of nitrogen (at 77.4 K), cationic methylene blue (MB), anionic methyl orange (MO), and Congo red (CR) from the aqueous solutions. Dye-PVA-AC-water interactions were modeled using the semiempirical quantum chemical method PM6. The percentage of dye removed (C(rem)) by the ACs was close to 100% at an equilibrium concentration (C(eq)) of less than 0.1 mM but decreased with increasing dye concentration. This decrease was stronger at C(eq) of less than 1 mM, and C(rem) was less than 50% at a C(eq) of 10-20 mM. For PVA and the PVA/AC composite containing C-7, the C(rem) values were minimal (<75%). The free energy distribution functions (f(ΔG)) for dye adsorption include one to three peaks in the -ΔG range of 1-60 kJ/mol, depending on the dye concentration range used and the spatial, charge symmetry of the hydrated dye ions and the structural characteristics of the adsorbents. The f(ΔG) shape is most complex for MO with the most asymmetrical geometry and charge distribution and adsorbed at concentrations over a large C(eq) range. For symmetrical CR ions, adsorbed over a narrow C(eq) range, the f(ΔG) plot includes mainly one narrow peak. MB has a minimal molecular size at a planar geometry (especially important for effective adsorption in slit-shaped pores) which explains its greater adsorptive capacity over that of MO or CR. Dye adsorption was greatest for ACs with the largest surface area but as molecular size increases adsorption depends to a greater extent on the pore size distribution in addition to total and nanopore surface areas and pore volume.


Assuntos
Carvão Vegetal/química , Corantes/isolamento & purificação , Recuperação e Remediação Ambiental/métodos , Polivinil/química , Adsorção , Resinas Compostas , Hidrogéis , Íons
17.
Biomaterials ; 31(18): 4789-94, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20303167

RESUMO

Porous carbons can be used for purification of bio-fluids due to their excellent biocompatibility with blood. Since the ability to adsorb a range of inflammatory cytokines within the shortest possible time is crucial to stop the progression of sepsis, the improvement of the adsorption rate is a key factor to achieving efficient removal of cytokines. Here, we demonstrate the effect of synthesis temperatures (from 600 degrees C to 1200 degrees C), carbon particle sizes (from below 35 microm to 300 microm), and annealing conditions (Ar, NH(3), H(2), Cl(2), and vacuum annealing) that determine the surface chemistry, on the ability of carbide-derived carbons (CDCs) to remove cytokines TNF-alpha, IL-6, and IL-1 beta from blood plasma. Optimization of CDC processing and structure leads to up to two orders of magnitude increase in the adsorption rate. Mesoporous CDCs that were produced at 800 degrees C from Ti(2)AlC with the precursor particle size of <35 microm and annealed in NH(3), displayed complete removal of large molecules of TNF-alpha in less than an hour, with >85% and >95% TNF-alpha removal in 5 and 30 min, respectively. This is a very significant improvement compared to the previously published results for CDC (90% TNF-alpha removal after 1h) and activated carbons. Smaller interleukin IL-6 and IL-1 beta molecules can be completely removed within 5 min. These differences in adsorption rates show that carbons with controlled porosity can also be used for separation of protein molecules.


Assuntos
Carbono/química , Citocinas/isolamento & purificação , Adsorção , Citocinas/sangue , Temperatura Alta , Humanos , Interleucina-1beta/sangue , Interleucina-1beta/isolamento & purificação , Interleucina-6/sangue , Interleucina-6/isolamento & purificação , Tamanho da Partícula , Porosidade , Propriedades de Superfície , Fator de Necrose Tumoral alfa/sangue , Fator de Necrose Tumoral alfa/isolamento & purificação
18.
Biomaterials ; 30(18): 3143-9, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19299007

RESUMO

The purpose of this study was to consider the use of a hydroxyapatite (HA) coated porous carbon matrix as a synthetic dental laminate substitute in osteo-odonto-keratoprosthetic (OOKP) design. 3 types of carbon meshes were coated with HA by sonoelectrochemical deposition. The materials were characterised by scanning electron microscopy (SEM) and HA deposition was characterised by elemental analysis and X-ray diffractometry (XRD). In vitro assays were carried out to quantify the effects of HA coating on human keratocyte adhesion. Cellular cytokine production was used to assess inflammatory potential. HA coating significantly increased keratocyte adhesion to the carbon matrix (p<0.01). The materials did not induce excessive cytokine production by the adherent keratocytes. In addition, the matrices themselves adsorbed significant levels of the cytokine IL-8 (p<0.05). The results indicate that HA coated carbon matrices provide a suitable environment to enhance in-growth of corneal cells without inducing further inflammation. The materials may also suppress excessive inflammation by adsorption of the cytokine IL-8 into the porous, internal carbon structure.


Assuntos
Carbono , Materiais Revestidos Biocompatíveis , Opacidade da Córnea/cirurgia , Durapatita , Implantes Experimentais , Telas Cirúrgicas , Adsorção , Carbono/toxicidade , Células Cultivadas/efeitos dos fármacos , Células Cultivadas/metabolismo , Materiais Revestidos Biocompatíveis/toxicidade , Córnea/citologia , Microanálise por Sonda Eletrônica , Humanos , Implantes Experimentais/efeitos adversos , Interleucina-6/química , Interleucina-6/metabolismo , Interleucina-8/química , Interleucina-8/metabolismo , Ceratite/prevenção & controle , Teste de Materiais , Microscopia Eletrônica de Varredura , Difração de Raios X
19.
J Sch Health ; 78(3): 149-56, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18307610

RESUMO

BACKGROUND: High trait anger and stress, ineffective patterns of anger expression, and coping are risk factors for the development of disease and negative social behaviors in children and adults. School connectedness may be protective against negative consequences in adolescents, but less is known about this in school-aged children. The purposes of this study were to characterize relationships between trait anger, stress, patterns of anger expression, resources for coping, and school connectedness and to determine if race and gender moderate these relationships in elementary school-aged children. METHODS: Using self-report, standardized instruments, a convenience sample of 166 fourth graders in 4 elementary schools in 1 US school district was assessed in the fifth week of the school year. RESULTS: School connectedness was positively associated with social confidence and behavior control and negatively associated with trait anger, anger-out, and stress. In multiple regression analyses to test for interactions, gender did not moderate the effects of school connectedness in any of the models, while race moderated the relationships between school connectedness and both stress and social confidence. Students with higher school connectedness had lower trait anger and anger-out and higher behavior control, regardless of gender and/or race. White students higher in school connectedness had lower stress and higher social confidence. CONCLUSIONS: Findings indicate the protective effect of school connectedness on trait anger, anger-out, and behavior control in school-aged children, regardless of race or gender. The protective effect of school connectedness on stress and social confidence may depend on race.


Assuntos
Adaptação Psicológica , Ira , Comportamento Infantil/psicologia , Estresse Psicológico/psicologia , Estudantes/psicologia , Negro ou Afro-Americano , Criança , Feminino , Humanos , Masculino , Testes Psicológicos , Análise de Regressão , Fatores de Risco , População Rural , Instituições Acadêmicas , Sudeste dos Estados Unidos , População Branca
20.
Biomaterials ; 29(11): 1638-44, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18207234

RESUMO

A prototype in-line filtration/adsorption device has been developed using novel synthetic pyrolysed carbon monoliths with controlled mesoporous domains of 2-50nm. Porosity was characterized by SEM and porosimetry. Removal of inflammatory cytokines TNF, IL-6, IL-1beta and IL-8 was assessed by filtering cytokine spiked human plasma through the walls of the carbon modules under pressure. The effect of carbon filtration on plasma clotting response and total plasma protein concentration was also assessed. Significant removal of the cytokines IL-6, IL-1beta and IL-8 was observed. Initially marked TNF removal diminished over time. The coagulation studies indicated that the carbon device does not exacerbate the propensity of blood plasma to clot. The total plasma protein concentration remained constant. The device offers a broader approach to the treatment of systemic inflammatory response syndrome (SIRS) by the removal of inflammatory mediators central to its progression.


Assuntos
Tecnologia Biomédica/instrumentação , Tecnologia Biomédica/métodos , Carbono/química , Citocinas/isolamento & purificação , Adsorção , Proteínas Sanguíneas/metabolismo , Citocinas/sangue , Humanos , Inflamação/sangue , Microscopia Eletrônica de Varredura
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