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1.
Cienc. tecnol. salud ; 8(1)2021. il 27 c
Article in Spanish | LILACS, LIGCSA, DIGIUSAC | ID: biblio-1352956

ABSTRACT

Polymeric membrane technologies demand the synthesis of new polymers to enhance their equilibrium, thermal, and transport properties. Therefore, the focus of this investigation was the evaluation of the equilibrium and thermal properties of a sulfonated fluoroblock copolymer blend membrane composed of sulfonated poly(styre-ne-isobutylene-styrene) (SIBS SO3H) and a novel sulfonated fluoroblock copolymer composed of poly(4-fluo-rostyrene) (P4FS), poly(styrene) (PS) and poly(isobutylene) (PIB). The fluoroblock copolymer was synthesized using Atom Transfer Radical Polymerization (ATRP) and cationic polymerization. First, the molecular weight and the thermal stability of the block copolymer were determined using Gel Permeation Chromatography (GPC) and Thermogravimetric Analysis (TGA). Second, the chemical composition was monitored utilizing Fourier Transform Infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy. The molecular weight of P4FS-b-PS was Mn ~ 36,100; this value increased 8% after the cationic polymerization. The equilibrium properties of the membrane were evaluated using the water uptake and Ion-Exchange Capacity. The degradation behavior and the thermal transitions were determined using TGA and Differential Scanning Calorimetry (DSC), respectively. This newly membrane exhibited water uptake higher than 608% related to the improvement of 36% in the ion-exchange capacity and the increment of 25.31% and 25.24% in the energy required to produce the thermal transitions induced by the addition of the sulfonated fluoroblock copolymer.


La tecnología de membranas poliméricas requiere de la síntesis de nuevos polímeros que mejoren sus propiedades de equilibrio, térmicas y de transporte. Esta investigación tuvo como objetivo determinar las pro-piedades de equilibrio y térmicas de una membrana compuesta de poli(estireno-isobutileno-estireno) sulfonado (SIBS SO3H) y un fluoropolímero en bloque sulfonado compuesto de poli(4-fluorostireno) (P4FS), poli(estireno) (PS) y poli(isobutileno) (PIB). El fluoropolímero en bloque se sintetizó utilizando la técnica de polimerización radical por transferencia atómica (ATRP por sus siglas en inglés) y polimerización catiónica. El peso molecular y la estabilidad térmica del fluoropolímero en bloque fueron determinadas por medio de Cromatografía de Permeación en Gel (GPC) y un análisis termogravimétrico (TGA). La composición química se monitorizó utilizando espectroscopía infrarroja por transformada de Fourier (FTIR) y espectroscopía de Resonancia Magnética Nuclear (RMN). El peso molecular de P4FS-b-PS fue Mn ~ 36,100; este valor aumentó un 8% después de la polimerización catiónica. Las propiedades de equilibrio de la membrana fueron evaluadas por medio de la absorción de agua y la capacidad de intercambio iónico. El comportamiento de degradación y las transiciones térmicas se determinaron utilizando TGA y Calorimetría Diferencial de Barrido (DSC). Esta nueva membrana exhibió una absorción de agua mayor del 608% relacionada con la mejora del 36% en la capacidad de intercambio iónico y el incremento en 25.31% y 25.24% en la energía requerida para producir las transiciones termales inducidas por la adición del fluoropolímero sulfonado en bloque.


Subject(s)
Polymers/analysis , Membranes, Artificial , Polystyrenes/analysis , Absorption , Polymerization , Ion Exchange , Molecular Weight
2.
Ciencia Tecnología y Salud ; 8(2): 260-268, 2021. il 27 c
Article in Spanish | LILACS-Express | LILACS, LIGCSA, DIGIUSAC | ID: biblio-1353264

ABSTRACT

La contaminación por microplásticos (MPs) de tamaño menor a 5 mm ha tomado relevancia en los últimos años debido a su impacto en los ecosistemas. En Guatemala, se carece de información relacionada con MPs, por lo que este estudio tuvo como objetivo evaluar la abundancia y características de MPs en cuatro playas del Pacífico de Guatemala, Ocós, Tulate, Sipacate y Las Lisas. Se colectaron muestras de arena en mayo y octubre de 2019. Los MPs se aislaron y se clasificaron por forma, y el tipo de polímero se identificó a través de un equipo de espectroscopia infrarroja con transformada de Fourier (ATR-FTIR). La abundancia expresada en MPs/m2 en mayo fue de 25.6, 5.6, 0.8 y 0 MPs/m2 para Tulate, Las Lisas, Ocós y Sipacate; mientras que en octubre fue de 59.6, 23.2, 17.6 y 17.6 MPs/m2 en Tulate, Ocós, Las Lisas y Sipacate. Fragmentos, foam, pellets y láminas fueron las formas predominantes de MPs que se encontraron en las playas. El análisis por ATR-FTIR muestra que los principales polímeros identificados en las playas son polietileno, poliestireno y polipropileno. Los resultados de este estudio indican que las playas del Pacífico de Guatemala están contaminadas por MPs de diferentes tipos de polímeros. Además, estos resultados ofrecen información importante a los responsables de la toma de decisiones sobre la eliminación y el manejo de la basura plástica marina.


Microplastics < 5 mm (MPs) pollution has gained relevance in the last years because of its impact on the ecosystems. In Guatemala, information related to MPS as an environmental stressor is lacking, that is why this study aimed to assess the abundance and characteristics of MPS in four beaches to the Pacific Ocean of Guatemala, Ocós, Tulate, Sipacate, and Las Lisas. Sand samples were collected in May and October 2019. MPs were isolated and classified by shape and the type of polymer was identified by using Attenuated Total Reflec-tion-Fourier Transform Infrared Spectroscopy (ATR-FTIR). The abundance expressed in MPs/m2 in May was 25.6, 5.6, 0.8 and 0 MPs/m2 in Tulate, Las Lisas, Ocós, and Sipacate; whereas in October was 59.6, 23.2, 17.6, and 17.6 M Ps /m2 in Tulate, Las Lisas, Ocós and Sipacate. Fragments, foam, pellets, and film were the predominant shapes found on the beaches. The ATR-FTIR analysis indicates that the main polymers identified in the beaches are polyethylene, polystyrene, and polypropylene. The results of this study indicate that the Pacific Beaches of Guatemala are contaminated by MPs of different types of polymers. These results offer important information to decision makers about disposal and management of marine plastic litter.


Subject(s)
Bathing Beaches , Environmental Pollution/analysis , Microplastics/analysis , Polypropylenes/analysis , Polystyrenes/analysis , Pacific Ocean , Polyethylene/analysis , Microplastics/adverse effects , Guatemala
4.
Rev. Assoc. Med. Bras. (1992) ; 66(supl.1): s31-s36, 2020.
Article in English | LILACS | ID: biblio-1057105

ABSTRACT

SUMMARY Hyperkalemia is a frequent finding in patients with chronic kidney disease (CKD). This increase in serum potassium levels is associated with decreased renal ion excretion, as well as the use of medications to reduce the progression of CKD or to control associated diseases such as diabetes mellitus and heart failure. Hyperkalemia increases the risk of cardiac arrhythmia episodes and sudden death. Thus, the control of potassium elevation is essential for reducing the mortality rate in this population. Initially, the management of hyperkalemia includes orientation of low potassium diets and monitoring of patients' adherence to this procedure. It is also important to know the medications in use and the presence of comorbidities to guide dose reduction or even temporary withdrawal of any of the potassium retention-related drugs. And finally, the use of potassium binders is indicated in both acute episodes and chronic hyperkalemia.


RESUMO A hiperpotassemia é um achado frequente em pacientes com doença renal crônica (DRC). Esta elevação do nível sérico de potássio está associada à diminuição da excreção renal do íon, assim como ao uso de medicações para retardar a progressão da DRC ou para controlar doenças associadas, como diabetes mellitus e insuficiência cardíaca. A hiperpotassemia aumenta o risco de episódios de arritmia cardíaca e morte súbita. Assim, o controle da elevação de potássio é essencial para a diminuição da taxa de mortalidade nessa população. O manejo da hiperpotassemia inclui, inicialmente, orientação de dietas com baixo teor de potássio e acompanhamento da aderência dos pacientes a esse procedimento. Também é importante conhecer as medicações em uso e a presença de comorbidades, a fim de orientar a redução de doses ou até mesmo a suspensão temporária de alguma das drogas relacionadas à retenção de potássio. E, finalmente, o uso de quelantes de potássio é indicado tanto em episódios agudos como nos casos de hiperpotassemia crônica.


Subject(s)
Humans , Potassium/adverse effects , Renal Insufficiency, Chronic/complications , Hyperkalemia/etiology , Polystyrenes/therapeutic use , Potassium/blood , Comorbidity , Silicates/therapeutic use , Renal Insufficiency, Chronic/blood , Hyperkalemia/drug therapy , Hyperkalemia/blood
5.
J. bras. nefrol ; 41(3): 440-444, July-Sept. 2019. tab, graf
Article in English | LILACS | ID: biblio-1040241

ABSTRACT

Abstract Hyperkalemia is one of the most common electrolyte disorders, responsible for a high number of adverse outcomes, including life-threatening arrhythmias. Potassium binders are largely prescribed drugs used for hyperkalemia treatment but unfortunately, there are many adverse events associated with its use, mostly gastrointestinal. Identification of patients at highest risk for the serious complications associated with the current potassium binders, such as colon necrosis and perforation, could prevent fatal outcomes. The authors present a case of a 56-year-old man with secondary diabetes and chronic renal disease that was treated for hyperkalemia with Calcium Polystyrene Sulfonate (CPS). He later presented with acute abdomen due to cecum perforation and underwent ileocecal resection but ultimately died from septic shock a week later. During surgery, a solid white mass was isolated in the lumen of the colon. The mass was identified as a CPS bezoar, a rare drug-mass formed in the gastrointestinal tract that contributed to the perforation. A previous history of partial gastrectomy and vagothomy was identified as a probable risk factor for the CPS bezoar development. Hopefully, the two new potassium binders patiromer and (ZS-9) Sodium Zirconium Cyclosilicate will help treat such high-risk patients, in the near future.


Resumo A hipercalemia é um dos distúrbios eletrolíticos mais comuns, responsável por um grande número de desfechos adversos, incluindo arritmias potencialmente fatais. Quelantes de potássio são amplamente prescritos para o tratamento da hipercalemia, mas infelizmente são muitos os eventos adversos associados ao seu uso, em particular os gastrointestinais. A identificação de pacientes com risco mais elevado para complicações graves associadas aos quelantes de potássio atualmente em uso, como necrose e perfuração do cólon, pode evitar desfechos fatais. O presente artigo descreve o caso de um homem de 56 anos com diabetes secundário e doença renal crônica em tratamento por hipercalemia com poliestirenossulfonato de cálcio (PSC). Posteriormente o paciente apresentou abdômen agudo devido a perfuração do ceco e foi submetido a uma ressecção ileocecal, mas acabou indo a óbito por choque séptico uma semana mais tarde. Durante a cirurgia, uma massa branca sólida foi isolada no lúmen do cólon. A massa foi identificada como um bezoar de PSC, uma massa de fármaco de rara ocorrência formada no trato gastrointestinal que contribuiu para a perfuração. História pregressa de gastrectomia parcial e vagotomia foi identificada como provável fator de risco para o desenvolvimento do bezoar de PSC. Espera-se que os dois novos quelantes de potássio - patiromer e ciclossilicato de zircônio sódico - ajudem a tratar pacientes de alto risco em um futuro próximo.


Subject(s)
Humans , Male , Middle Aged , Polystyrenes/therapeutic use , Bezoars/complications , Cecum/pathology , Hyperkalemia/drug therapy , Intestinal Perforation/etiology , Silicates/therapeutic use , Fatal Outcome , Diabetes Mellitus/etiology , Hyperkalemia/etiology
6.
Rev. Assoc. Med. Bras. (1992) ; 64(8): 680-683, Aug. 2018. graf
Article in English | LILACS | ID: biblio-1041022

ABSTRACT

SUMMARY Sodium polystyrene sulfonate (PSP) or Kayexalate is a cation-exchange resin, widely used in the management of hyperkalaemia due to renal disease. A rare, yet potentially dangerous, adverse event related to sodium polystyrene sulfonate use is intestinal mucosal injury, especially in the colon. The injury to the gastrointestinal mucosa can range from mild and superficial to wall necrosis and bowel perforation. The mechanism that leads to mucosal damage remains unclear. However, it is believed that sorbitol, commonly given to counteract PSP's tendency to cause constipation, may play an important role in the development of gastrointestinal injury. Other potential risk factors are uraemia or end-stage renal disease, hemodynamic instability, solid organ transplantation, postoperative status and concomitant opioid administration. The authors present a case of diarrhoea and haematochezia after the administration of PSP without sorbitol, in a patient with hyperkalaemia due to acute kidney injury, in the absence of other risk factors. A colonoscopy was performed and revealed a rectal ulcer which histological findings were suggestive of mucosal injury due to Kayexalate deposition. This case supports the concept that this widely used drug can itself, without sorbitol, cause injury to the gastrointestinal wall. Even though this is a rare adverse effect, the widespread use of this medication may put a large population at risk.


RESUMO O polistireno sulfonato de sódio (PSP) ou kayexalato é uma resina de troca iônica, amplamente usada no tratamento da hipercalemia associada à doença renal. Um efeito adverso raro, mas potencialmente grave, dessa terapêutica é a agressão à parede do trato gastrointestinal, principalmente ao nível do cólon, que pode ser ligeira e superficial ou culminar em necrose e perfuração intestinal. O mecanismo pelo qual o PSP lesa a mucosa intestinal não é totalmente conhecido. Contudo, pensa-se que o sorbitol, frequentemente administrado em simultâneo para contrabalançar o efeito obstipante do PSP, possa ter um papel preponderante no desenvolvimento de lesão gastrointestinal. Outros potenciais fatores de risco são a presença de uremia ou doença renal em estágio terminal, instabilidade hemodinâmica, pós-operatório, pós-transplante renal e a administração concomitante de opioides. Os autores descrevem um caso de diarreia e hematoquesias após a administração de PSP sem sorbitol, numa paciente com hipercalemia secundária a lesão renal aguda, sem outros fatores de risco para o desenvolvimento desse efeito adverso. A investigação etiológica com colonoscopia revelou a presença de uma úlcera retal, cujo estudo histológico foi compatível com lesão por deposição de cristais de kayexalato. Este relato incomum reforça o conceito de que este fármaco de uso frequente, mesmo na ausência de sorbitol, pode ser lesivo para a mucosa intestinal. Assim, e apesar de este ser um efeito adverso raro, a utilização difundida do PSP coloca uma vasta população em risco.


Subject(s)
Humans , Female , Aged, 80 and over , Polystyrenes/adverse effects , Rectal Diseases/chemically induced , Ulcer/chemically induced , Cation Exchange Resins/adverse effects , Rectal Diseases/pathology , Rectal Diseases/diagnostic imaging , Sorbitol/adverse effects , Ulcer/pathology , Ulcer/diagnostic imaging , Biopsy , Risk Factors , Colonoscopy , Acute Kidney Injury/drug therapy , Hyperkalemia/drug therapy
7.
Rev. luna azul ; 47: 36-66, 01 julio 2018. tab
Article in English, Spanish | LILACS | ID: biblio-1008413

ABSTRACT

Este trabajo discute los resultados de la investigación experimental conducida para estudiar la inclusión de materiales reciclables como cascarilla de arroz, poliestireno expandido (icopor) y tereftalato de polietileno ­PET­ en la masilla para construcción liviana empleada para la fabricación de placas de Drywall como respuesta a la minimización del impacto ambiental y al aprovechamiento de las propiedades de los materiales desechados que son nuevamente introducidos en procesos productivos con el fin de obtener baja conductividad térmica, alta capacidad calorífica, alta capacidad de absorción sonora y cumplir con la normativa internacional para materiales de construcción; para ello se realizaron pruebas para medir cuatro propiedades como son el aislamiento térmico, capacidad calorífica y pruebas físico-mecánicas (resistencia a la flexión y resistencia a la tracción de clavo) por medio de probetas, teniendo en cuenta la normativa ASTM C 1396/C1396M-04 y ASTM C473-03, mientras que para la prueba de aislamiento acústico se utilizaron las normas ISO 16283-1 e ISO 717-1; los resultados obtenidos se procesaron aplicando un análisis estadístico multivariado empleando el software Statgraphics Centurion XVII que estableció los valores máximos y mínimos, la correlación de Pearson y ordinal de Spearman como método de análisis para el reporte del material más eficiente respecto a las cuatro propiedades medidas. La cascarilla de arroz, sustituyendo en un 60 % el peso del yeso en la masilla original, reportó los mejores resultados en cada una de las cuatro pruebas realizadas a lo largo de la investigación; de esta manera se confirma que es un material adecuado para la implementación en procesos de construcción liviana dado que demuestra que los materiales reciclables son eficientes y además poseen propiedades específicas como resistencia, liviandad y flexibilidad que le dan un valor agregado para ser utilizados nuevamente como reemplazo de materiales tradicionales.


This paper discusses the results of the experimental research conducted to study the inclusion of recyclable materials such as rice husks, expanded polystyrene (Styrofoam), and polyethylene terephthalate (PET) in the mastic for lightweight construction used for the manufacture of Drywall plates in response to the minimization of the environmental impact, and the use of the properties of discarded materials that are, once again, introduced in productive processes to obtain low thermal conductivity, high heat capacity, high sound absorption capacity and that comply with international standards for construction materials. For this purpose, tests to measure four properties such as Thermal Insulation, Calorific Capacity and Physical-Mechanical Testing (Flexural Resistance and Nail Tensile Strength) were carried out by means of test pieces taking into account the ASTM C1396 / C1396M - 04 and ASTM C473 - 03, while ISO 16283-1 and ISO 717-1 were used for the acoustic insulation test. The results obtained were processed by applying a multivariate statistical analysis using the Statgraphics Centurion XVII-2015 software that established the maximum and minimum values, Pearson's correlation and Spearman's ordinal as the analysis method for reporting the most efficient material regarding the four measured properties. Rice husk, replacing by 60% the weight of plaster in the original mastic, reported the best results in each of the four tests carried out throughout the research. In this way, it is confirmed that it is a suitable material for the implementation in lightweight construction processes as it shows that recyclable materials are efficient and also have specific properties such as strength, lightness and flexibility that give an added value to be used again as a replacement of traditional materials.


Subject(s)
Humans , Recycling , Polystyrenes , Thermal Conductivity , Acoustics
8.
Article in Korean | WPRIM | ID: wpr-714097

ABSTRACT

The purpose of our study is to compare the adhesion and biofilm formation abilities of isolates from water discharged from dental unit waterlines (DUWLs). Bacteria were isolated from a total of 15 DUWLs. Twelve isolates were selected for the experiment. To confirm the adhesion ability of the isolates, each isolate was attached to a glass coverslip using a 12-well plate. Plates were incubated at 26℃ for 7 days, and the degree of adhesion of each isolate was scored. To verify the biofilm formation ability of each isolate, biofilms were allowed to form on a 96-well polystyrene flat-bottom microtiter plate. The biofilm accumulations of all isolates formed at 26℃ for 7 days were identified and compared. A total of 56 strains were isolated from 15 water samples including 12 genera and 31 species. Of the 56 isolates, 12 isolates were selected according to the genus and used in the experiment. Sphingomonas echinoides, Methylobacterium aquaticum, and Cupriavidus pauculus had the highest adhesion ability scores of +3 among 12 isolates. Among these three isolates, the biofilm accumulation of C. pauculus was the highest and that of S. echinoides was the third-most abundant. The lowest biofilm accumulations were identified in Microbacterium testaceum and M. aquaticum. Most isolates with high adhesion ability also exhibited high biofilm formation ability. Analysis of adhesion and biofilm formation of the isolates from DUWLs can provide useful information to understand the mechanism of DUWL biofilm formation and development.


Subject(s)
Bacteria , Bacterial Adhesion , Biofilms , Cupriavidus , Glass , Infection Control, Dental , Methylobacterium , Polystyrenes , Sphingomonas , Water , Water Microbiology
9.
Article in English | WPRIM | ID: wpr-766048

ABSTRACT

PURPOSE: The goal of this study was to develop and validate a standardized in vitro pathogenic biofilm attached onto saliva-coated surfaces. METHODS: Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis) strains were grown under anaerobic conditions as single species and in dual-species cultures. Initially, the bacterial biomass was evaluated at 24 and 48 hours to determine the optimal timing for the adhesion phase onto saliva-coated polystyrene surfaces. Thereafter, biofilm development was assessed over time by crystal violet staining and scanning electron microscopy. RESULTS: The data showed no significant difference in the overall biomass after 48 hours for P. gingivalis in single- and dual-species conditions. After adhesion, P. gingivalis in single- and dual-species biofilms accumulated a substantially higher biomass after 7 days of incubation than after 3 days, but no significant difference was found between 5 and 7 days. Although the biomass of the F. nucleatum biofilm was higher at 3 days, no difference was found at 3, 5, or 7 days of incubation. CONCLUSIONS: Polystyrene substrates from well plates work as a standard surface and provide reproducible results for in vitro biofilm models. Our biofilm model could serve as a reference point for studies investigating biofilms on different surfaces.


Subject(s)
Bacterial Adhesion , Biofilms , Biomass , Fusobacterium nucleatum , Fusobacterium , Gentian Violet , In Vitro Techniques , Microscopy, Electron, Scanning , Polystyrenes , Porphyromonas gingivalis , Porphyromonas
10.
Article in Korean | WPRIM | ID: wpr-716739

ABSTRACT

The purpose of this study is to investigate the correlation of cell surface hydrophobicity (CSH) and biofilm formation or adhesion in Candida albicans (C. albicans) and several pathogenic bacteria. All of C. albicans (n=82) and 7 bacterial species (Escherichia coli, n=25; Klebsiella pneumoniae, n=33; Morganella morganii, n=21; Proteus mirabilis, n=33; Proteus vulgaris, n=12; Pseudomonas aeruginosa, n=31; Staphylococcus aureus, n=31) were isolated clinically. CSH was quantified with microbial adhesion to hydrocarbons. Biofilm formation was determined by tetrazolium salt reduction assay. Adhesion assay was performed by counting colonies after culture the microbes adhered to HeLa cells. Although high CSH-expressing bacterial species showed greater adherence to HeLa cells and larger amounts of biofilm formation on polystyrene, the significant relationships within same species were not shown. In C. albicans, however, strong positive correlations were observed between CSH and biofilm formation (r =0.708; p < 0.05) or cell adhesion (r =0.509; p < 0.05). These results suggest that hydrophobic force of bacteria may play a minor role in adhesion and biofilm formation, but CSH of C. albicans may be an important factor for adherence on surface and biofilm forming process.


Subject(s)
Bacteria , Biofilms , Candida albicans , Candida , Cell Adhesion , HeLa Cells , Humans , Hydrocarbons , Hydrophobic and Hydrophilic Interactions , Klebsiella pneumoniae , Morganella morganii , Polystyrenes , Proteus mirabilis , Proteus vulgaris , Pseudomonas aeruginosa , Staphylococcus aureus
11.
Rev. med. Risaralda ; 23(2): 4-9, jul.-dic. 2017. ilus, tab
Article in Spanish | LILACS, COLNAL | ID: biblio-902074

ABSTRACT

El objetivo de la investigación fue evaluar la capacidad de formación de biopelículas en especies del género Candida provenientes de muestras clínicas con procesos infecciosos. La muestra estuvo constituida por 70 aislados obtenidos de laboratorios clínicos privados. Para la identificación de las especies se utilizó la Prueba de tubo germinativo y la técnica de microcultivo en agar harina de maíz con tween 80, mientras que la cuantificación de la capacidad de formación de biopelículas se realizó por la técnica de microplaca de poliestireno. Entre los resultados obtenidos en la investigación las especies aisladas fueron: Candida glabrata (34%), Complejo Candida albicans (30%), Complejo Candida parapsilosis (27%) y Candida tropicalis (9%), de las cuales 41 aislados (59%) formaron biopelículas, resultando el Complejo Candida albicans y Candida glabrata las especies con mayor grado de formación de biopelículas con 29% cada una, seguida de Complejo Candida parapsilosis con 27% y Candida tropicalis con 15%. Las cepas que tuvieron mayor formación de biopelículas provenían de orina, seguidas de secreción ótica, secreción vaginal y sangre, sin embargo al aplicar la prueba de Chi-cuadrado (x2) de Pearson se determinó que no existe asociación estadísticamente significativa entre la capacidad de formación de biopelículas y el grado de formación con la procedencia clínica así como tampoco hay asociación entre la capacidad de formación de biopelículas y grado de formación con la especie involucrada (p > 0,05)


The aim of this research was to evaluate the capability of biofilm formation in Candida genus species from clinical samples with infectious conditions. The sample consisted of 70 isolates obtained from private clinical laboratories. Germ tube test and agar cornmeal with tween 80 microculture technique were used as species identification, meanwhile, quantification of biofilm formation capacity was performed by the polystyrene microplate technique. Among the results obtained in the research, isolated species were: Candida glabrata (34%), Candida albicans Complex (30%), Candidaparapsilosis Complex (27%) and Candida tropicalis (9%), of which 41 isolates (59%) formed biofilms, resulting Candida albicans and Candida glabrata Complex species with the highest degree of biofilms with 29% each, followed by Candida parapsilosis Complex with 27% and Candida tropicalis with 15%. Strains with more biofilm formation came from urine, followed by ear discharge, vaginal secretion and blood. However, by applying the Chi squaretest the Pearson, it was determined that there was no statistically significant association between thecapability of biofilm formation and the formation degree with clinical origin, neither there is association between the ability of biofilm formation and the formation degree with the species involved (p> 0.05).


Subject(s)
Humans , Female , Candida , Candida albicans , Biofilms , Vaginal Discharge , Bodily Secretions , Polysorbates , Polystyrenes , Zea mays , Candida glabrata , Candida tropicalis , Agar , Candida parapsilosis , Laboratories
12.
Article in English | WPRIM | ID: wpr-15453

ABSTRACT

PURPOSE: The entry of bacteria or harmful substances through the epithelial seal of human gingival keratinocytes (HGKs) in the junctional epithelium (JE) is blocked by specialized intercellular junctions such as E-cadherin junctions (ECJs). However, the influence of roughened substrates, which may occur due to apical migration of the JE, root planing, or peri-implantitis, on the development of the ECJs of HGKs remains largely unknown. METHODS: HGKs were cultured on substrates with varying levels of roughness, which were prepared by rubbing hydrophobic polystyrene dishes with silicon carbide papers. The activity of c-Jun N-terminal kinase (JNK) was inhibited with SP600125 or by transfection with JNK short hairpin RNA. The development of intercellular junctions was analyzed using scanning electron microscopy or confocal laser scanning microscopy after immunohistochemical staining of the cells for E-cadherin. The expression level of phospho-JNK was assessed by immunoblotting. RESULTS: HGKs developed tight intercellular junctions devoid of wide intercellular gaps on smooth substrates and on rough substrates with low-nanometer dimensions (average roughness [Ra]=121.3±13.4 nm), although the ECJs of HGKs on rough substrates with low-nanometer dimensions developed later than those of HGKs on smooth substrates. In contrast, HGKs developed short intercellular junctions with wide intercellular gaps on rough substrates with mid- or high-nanometer dimensions (Ra=505.3±115.3 nm, 867.0±168.6 nm). Notably, the stability of the ECJs was low on the rough substrates, as demonstrated by the rapid destruction of the cell junction following calcium depletion. Inhibition of JNK activity promoted ECJ development in HGKs. JNK was closely associated with cortical actin in the regulation of ECJs in HGKs. CONCLUSIONS: These results indicate that on rough substrates with nanometer dimensions, the ECJs of HGKs develop slowly or defectively, and that this effect can be reversed by inhibiting JNK.


Subject(s)
Actins , Bacteria , Cadherins , Calcium , Dental Implants , Epithelial Attachment , Humans , Immunoblotting , Intercellular Junctions , JNK Mitogen-Activated Protein Kinases , Keratinocytes , Microscopy, Confocal , Microscopy, Electron, Scanning , Peri-Implantitis , Periodontal Diseases , Polystyrenes , Re-Epithelialization , RNA, Small Interfering , Root Planing , Silicon , Transfection
13.
Rev. luna azul ; (43): 286-310, jul.-dic. 2016. ilus, tab
Article in Spanish | LILACS-Express | LILACS | ID: biblio-830551

ABSTRACT

En el proceso de fabricación de autopartes se incluye el polipropileno (PP) como materia prima principal y la fibra de vidrio como insumo para la producción de ventiladores utilizados en los sistemas de refrigeración de los automotores. Los estándares de fabricación deben garantizar la resistencia de los productos en condiciones a las que estarán sometidos dentro del motor. Para lograrlo, el polipropileno es mezclado con fibra de vidrio en el proceso de inyección para aumentar la resistencia y la dureza del producto final, debido a que está expuesto a cambios de temperatura, choques con otras piezas, desgaste e impactos inesperados en el vehículo. Este estudio sintetizó y caracterizó un material obtenido a partir de la mezcla polipropileno puro-poliestireno expandido (EPS) (icopor) reciclado como una alternativa de aprovechamiento para el icopor dentro del proceso de fabricación de autopartes a modo de sustituto de la fibra de vidrio en el proceso de producción, siguiendo pasos como el tamizaje de los tamaños de material, la mezcla de los mismos, la obtención de probetas y la realización de ensayos mecánicos y térmicos. El objetivo fue comparar las propiedades mecánicas y térmicas del material obtenido (PP-EPS) con el material actualmente utilizado (PP-fibra de vidrio) para el que no se tenían estudios previos y de esta forma determinar la viabilidad de incorporación de un residuo a un proceso productivo y evitar su disposición directa favoreciendo el reciclaje del mismo. Las mezclas se caracterizaron mediante ensayos de tensión-deformación, dureza Shore A y análisis termogravimétrico (TGA) de los cuales se obtuvo favorecimiento en las propiedades térmicas y reducción de la resistencia mecánica en el uso de icopor, resaltando por supuesto el ahorro significativo en el cambio de insumos del proceso productivo.


Polypropylene (PP) as main raw material and fiberglass as input for the production of fans used in the cooling systems of motor is included in the process of manufacturing parts. Manufacturing standards must guarantee the resistance of the product in conditions that will be subject within the engine. To achieve this, the polypropylene is mixed with fiberglass in the injection process to increase the strength and hardness of the final product, as it is exposed to temperature changes, impacts with other parts, wear and unexpected impacts on the vehicle. This study synthesized and characterized a material obtained from the pure-polypropylene blend expanded polystyrene (EPS) (polystyrene) recycling as an alternative use for polystyrene in the auto parts manufacturing process as a substitute for fiberglass production process, following steps as screening media sizes, the mixture thereof, and obtaining specimens performing mechanical and thermal tests. The aim was to compare the mechanical and thermal properties of the material obtained (PP-EPS) with the material currently used (PP-fiberglass) for which they had no previous studies and thus determine the feasibility of incorporating a waste to a production in order to avoid direct disposal and thus promote the recycling process itself. The blends were characterized by stress-strain tests, Shore A hardness and thermogravimetric analysis (TGA) of which was obtained favoring the thermal properties and mechanical strength reduction in the use of polystyrene, of course emphasizing the significant savings in change of inputs in the production process.


Subject(s)
Humans , Solid Waste , Polystyrenes , Waste Products , Recycling
14.
Article in English | WPRIM | ID: wpr-250313

ABSTRACT

The effect of surface charges on the cellular uptake rate and drug release profile of tetrandrine-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TPNs) was studied. Stabilizer-free nanoprecipitation method was used in this study for the synthesis of TPNs. A typical layer-by-layer approach was applied for multi-coating particles' surface with use of poly(styrene sulfonate) sodium salt (PSS) as anionic layer and poly(allylamine hydrochloride) (PAH) as cationic layer. The modified TPNs were characterized by different physicochemical techniques such as Zeta sizer, scanning electron microscopy and transmission electron microscopy. The drug loading efficiency, release profile and cellular uptake rate were evaluated by high performance liquid chromatography and confocal laser scanning microscopy, respectively. The resultant PSS/PAH/PSS/PAH/TPNs (4 layers) exhibited spherical-shaped morphology with the average size of 160.3±5.165 nm and zeta potential of-57.8 mV. The encapsulation efficiency and drug loading efficiency were 57.88% and 1.73%, respectively. Multi-layer coating of polymeric materials with different charges on particles' surface could dramatically influence the drug release profile of TPNs (4 layers vs. 3 layers). In addition, variable layers of surface coating could also greatly affect the cellular uptake rate of TPNs in A549 cells within 8 h. Overall, by coating particles' surface with those different charged polymers, precise control of drug release as well as cellular uptake rate can be achieved simultaneously. Thus, this approach provides a new strategy for controllable drug delivery.


Subject(s)
Antineoplastic Agents, Phytogenic , Chemistry , Benzylisoquinolines , Chemistry , Cell Line, Tumor , Drug Liberation , Humans , Lactic Acid , Chemistry , Nanoparticles , Chemistry , Metabolism , Polyamines , Chemistry , Polyglycolic Acid , Chemistry , Polystyrenes , Chemistry , Static Electricity
15.
Rev. argent. microbiol ; 47(3): 256-260, set. 2015. ilus, tab
Article in Spanish | LILACS | ID: biblio-843132

ABSTRACT

An expanded-polystyrene factory located in northern Buenos Aires reported unusual dark spots causing esthetic damage in their production. A fungal strain forming black-olive colonies on extract malt agar medium was isolated from the damaged material and identified as Aureobasidium pullullans var. melanogenum. This fungus is particularly known for its capacity to produce hydrolytic enzymes and a biodegradable extracellular polysaccharide known as pullulan, which is used in the manufacture of packaging material for food and medicine. Laboratory tests were conducted to characterize its growth parameters. It was found that the organism was resistant to a wide range of pHs but did not survive at temperatures over 65 °C. The proposed action plan includes drying of the material prior to packaging and disinfection of the machinery used in the manufacturing process and of the silos used for raw material storage.


Una fábrica de poliestireno expandido situada en el norte de Buenos Aires reportó casos inusuales de manchas oscuras que causaban un daño estético en su producción. A partir del material dañado se aisló una cepa de hongo que forma colonias negro-oliváceas en medio agar-malta y que fueron identificadas como Aureobasidium pullullans var. melanogenum. Este hongo es particularmente conocido por su capacidad de producir enzimas hidrolíticas y un polisacárido extracelular biodegradable, el pululano, utilizado para la fabricación de envases para alimentos y medicinas. Se llevaron a cabo ensayos de laboratorio para caracterizar sus parámetros de crecimiento. Se encontró que el organismo es resistente a un amplio rango de pH, pero no sobrevive a temperaturas superiores a 65 °C. El plan de acción propuesto incluye el secado del material antes de su envasado y la desinfección tanto de la maquinaria utilizada en el proceso de fabricación como de los silos utilizados para el almacenamiento de la materia prima.


Subject(s)
Polystyrenes/metabolism , Disinfection/methods , Fungi/growth & development , Polystyrenes/analysis
16.
Article in English | WPRIM | ID: wpr-221783

ABSTRACT

BACKGROUND: Multi-drug resistant (MDR) Acinetobacter baumannii has emerged as one of the most important nosocomial pathogens. In addition to the diverse resistance mechanisms, some A. baumannii strains are known to have biofilm-producing capacity, thereby decreasing antibiotic effectiveness. MATERIALS AND METHODS: This study was designed to assess biofilm-producing capacity of three different MDR A. baumannii strains with diverse resistance mechanisms (OXA-51, IMP-1 and VIM-2 type beta-lactamases), and intended to compare the effect of each antibiotic regimen (rifampicin, colistin, imipenem, tigecycline, rifampicin-imipenem and rifampicin-colistin) on mature A. baumannii biofilms using in vitro polystyrene plate biofilm assay. RESULTS: Among three MDR A. baumannii strains, only VIM-2 strain produced strong biofilm compared to the controls (optical density, 8.04 +/- 2.16 vs. 0.49 +/- 0.26). Regarding VIM-2 strains, none of imipenem, colistin and rifampicin reduced biofilm formation alone at MIC of each antibiotic agent (inhibition of biofilm synthesis, less than 30%). In comparison, tigecyclin (0.76 +/- 0.23), imipenem-rifampicin (1.07 +/- 0.31) and colistin-rifampicin (1.47 +/- 0.54) showed a significant inhibition of biofilm synthesis compared to the positive controls at 48 hours after incubation (P<0.01). Tigecycline inhibited biofilm formation even at the one fourth level of MIC (1.17 +/- 0.21). Likewise, both imipenem and colistin were also effective even with the reduced concentrations when those were combined with rifampicin. Such biofilm-inhibiting effects with those antibiotic regimens sustained up to 96 hours after incubation. CONCLUSION: Tigecycline, imipenem-rifampicin and colistin-rifampicin would be effective for the prevention or reduction of biofilm formation caused by A. baumannii strains.


Subject(s)
Acinetobacter baumannii , Anti-Bacterial Agents , Biofilms , Colistin , Imipenem , Polystyrenes , Rifampin
17.
Article in Korean | WPRIM | ID: wpr-195467

ABSTRACT

BACKGROUND AND OBJECTIVES: Recurrent laryngeal nerve (RLN) damage commonly occurs from a thyroid surgery and causes communication impairment, aspiration and dysphagia. The purpose of this study is to develop a polycaprolactone (PCL) nerve guide conduit (NGC) coated with conductive materials for facilitating regeneration from the RLN defects and to evaluate the usefulness of the PCL NGC coated with conductive materials in a rabbit model. MATERIALS AND METHODS: The PCL NGCs coated with conductive materials were fabricated for this study. The types of conductive materials were single-walled carbon nanotubes (SWNTs) and poly (3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) which were coated on the PCL NGCs by layer-by-layer (LBL) assembly techniques. An 8-mm segment of left RLN was resected in 24 New Zealand white rabbits. Three different NGCs (PCL and PCL with two conductive materials) were interposed between both stumps and fixed with suture. For the assessment of functional regeneration, the vocal cord mobility was observed using endoscopic system after RLN stimulation, and the motion change was analyzed. The atrophies of thyroarytenoid muscle and nerve growth were evaluated by Hematoxylin-Eosin (H-E) and toluidine blue (T-B) staining, respectively. Immunohistochemical study using anti-neurofilament, S-100 staining was further performed to evaluate the nerve regeneration. RESULTS: In endoscopic evaluation, the group with conductive PCL NGCs showed an improved tendency of vocal cord mobility compared to that of the other group. Nerve growth was observed with the time for 8 weeks in all groups and immunohistochemical staining revealed the expression of neurofilament and S-100 in regenerated nerve in all groups. The atrophies of thyroarytenoid muscle in the group with conductive PCL NGCs was also shown to be decreased compared to that of the nonconductive PCL NGC group. CONCLUSION: The study shows that PCL NGC coated with conductive materials appears to be a good alternative option for the repair and regeneration of RNL damages.


Subject(s)
Atrophy , Deglutition Disorders , Laryngeal Muscles , Nanotubes, Carbon , Nerve Regeneration , Polystyrenes , Rabbits , Recurrent Laryngeal Nerve , Regeneration , Sutures , Thyroid Gland , Tolonium Chloride , Vocal Cords
18.
Article in Chinese | WPRIM | ID: wpr-310962

ABSTRACT

The objective of the study was to prepare and evaluate the quality of curcumin-piperinedual drug loaded self-microemulsifying drug delivery system(Cur-PIP-SMEDDS). Simplex lattice design was constructed using optimal oil phase, surfactant and co-surfactant concentration as independent variables, and the curcumin and piperine were used as model drugs to optimize Cur-PIP-SMEDDS formulation. In the present study, the drug loadings of curcumin and piperine, mean particle size of Cur-PIP-SMEDDS were made as indicators, and the experiment design, model building and response surface analysis were established using Design Expert 8. 06 software to optimize and verify the composition of SMEDDS formulation. The quality of Cur-PIP-SMEDDS was evaluated by observing the appearance status, transmission electron microscope micrographs and determining particle diameter, electric potential, drug entrapment efficiency and drug loading of it. As a result, the optimal formulation of SMEDDS was CapryoL 90-Cremophor RH40-TranscutoL HP (10:60:30). The appearance of Cur-PIP-SMEDDS remained clarified and transparent, and the microemulsion droplets appeared spherical without aggregation with uniform particle size distribution. The mean size of microemulsion droplet formed from Cur-PIP-SMEDDS was 15.33 nm, the drug loading of SMEDDS for Cur and PIP were 40.90 mg · g(-1) and 0.97 mg · g(-1), respectively, the drug entrapment efficiency were 94.98% and 90.96%, respectively. The results show that Cur-PIP-SMEDDS can increase the solubility and stability of curcumin significantly, in the expectation of enhancing the bioavailability of it. Taken together, these findings can provide the reference to a preferable choice of the Cur formulation and contribute to therapeutic application in clinical research.


Subject(s)
Alkaloids , Chemistry , Benzodioxoles , Chemistry , Chemistry, Pharmaceutical , Methods , Curcumin , Chemistry , Drug Carriers , Chemistry , Drug Combinations , Drug Delivery Systems , Drugs, Chinese Herbal , Chemistry , Emulsions , Chemistry , Methylmethacrylates , Chemistry , Particle Size , Piperidines , Chemistry , Polystyrenes , Chemistry , Polyunsaturated Alkamides , Chemistry
19.
Article in English | WPRIM | ID: wpr-92618

ABSTRACT

OBJECTIVES: This study was designed to evaluate the synergistic antibacterial effect of xylitol and ursolic acid (UA) against oral biofilms in vitro. MATERIALS AND METHODS: S. mutans UA 159 (wild type), S. mutans KCOM 1207, KCOM 1128 and S. sobrinus ATCC 33478 were used. The susceptibility of S. mutans to UA and xylitol was evaluated using a broth microdilution method. Based on the results, combined susceptibility was evaluated using optimal inhibitory combinations (OIC), optimal bactericidal combinations (OBC), and fractional inhibitory concentrations (FIC). The anti-biofilm activity of xylitol and UA on Streptococcus spp. was evaluated by growing cells in 24-well polystyrene microtiter plates for the biofilm assay. Significant mean differences among experimental groups were determined by Fisher's Least Significant Difference (p < 0.05). RESULTS: The synergistic interactions between xylitol and UA were observed against all tested strains, showing the FICs < 1. The combined treatment of xylitol and UA inhibited the biofilm formation significantly and also prevented pH decline to critical value of 5.5 effectively. The biofilm disassembly was substantially influenced by different age of biofilm when exposed to the combined treatment of xylitol and UA. Comparing to the single strain, relatively higher concentration of xylitol and UA was needed for inhibiting and disassembling biofilm formed by a mixed culture of S. mutans 159 and S. sobrinus 33478. CONCLUSIONS: This study demonstrated that xylitol and UA, synergistic inhibitors, can be a potential agent for enhancing the antimicrobial and anti-biofilm efficacy against S. mutans and S. sobrinus in the oral environment.


Subject(s)
Biofilms , Hydrogen-Ion Concentration , Polystyrenes , Streptococcus , Streptococcus mutans , Streptococcus sobrinus , Xylitol
20.
Article in Korean | WPRIM | ID: wpr-208898

ABSTRACT

The other generalized type of epidermolysis bullosa simplex (EBS) is a genetic blistering skin disease, caused by a mutation of the genes encoding keratin 5 and 14. EBS starts at birth and is characterized by generalized blisters following a minor trauma that heals with hyperpigmentation. A 19-year-old man presented with 19-year history of multiple erythematous vesicles in a herpetiform arrangement on the trunk, axilla, and thigh with post-inflammatory hyper-pigmentations. On light and electron microscopy, the biopsy specimen showed intraepidermal blisters that formed within the basal keratinocyte. The serum from a patient with bullous pemphigoid antibody and laminin 5 antibody showed the linear deposition at the floor of the blister on immunofluorescence mapping study. On the basis of our clinical, microscopic, and immunofluorescence findings, we diagnosed the patient as having a generalized type of EBS. Herein, we report on an interesting case of the other generalized type of EBS.


Subject(s)
Axilla , Biopsy , Blister , Cell Adhesion Molecules , Epidermolysis Bullosa , Epidermolysis Bullosa Simplex , Floors and Floorcoverings , Fluorescent Antibody Technique , Humans , Hyperpigmentation , Keratin-5 , Keratinocytes , Laminin , Light , Methylmethacrylates , Microscopy, Electron , Parturition , Pemphigoid, Bullous , Polystyrenes , Skin Diseases , Thigh
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