Efeito anti-erosivo de soluções contendo diferentes polímeros / Anti-erosive effect of solutions containing different polymers

O desgaste erosivo tem sido reconhecido como uma condição frequente nos últimos anos, principalmente devido a mudanças nos hábitos alimentares e comportamentais das populações em geral. Considerando a natureza irreversível desta condição, o diagnóstico precoce e a adoção de medidas preventivas são muito importantes. Dentre elas, a adição de polímeros a produtos de higiene bucal associados ou não a fluoretos apresenta-se como uma alternativa promissora, já que alguns polímeros apresentam compatibilidade com as estruturas dentais e capacidade de formação de um filme protetor. Este estudo foi subdivido em três artigos que visaram, através de diferentes abordagens, investigar o efeito anti- erosivo de polímeros formadores de filme, bem como o efeito da associação destes com fluoretos. O primeiro artigo consistiu em uma revisão da literatura sobre aspectos relacionados ao potencial de utilização dos polímeros para a prevenção da erosão dental. O segundo artigo consistiu em um estudo de varredura para verificar a capacidade de redução da dissolução da hidroxiapatita promovida por soluções contendo quatro polímeros (polioxirano, hidroxipropilmetilcelulose, pectina e um copolímero do polimetacrilato) associadas ou não com fluoreto de sódio -F (225 ppm F- ) e fluoreto de sódio + cloreto de estanho (800 ppm Sn2+) - FS. A mensuração do potencial zeta da hidroxiapatita dispersa tratada com as soluções experimentais foi realizada a fim de complementar a análise. O terceiro artigo consistiu em um estudo de ciclagem erosiva/reendurecedora na presença de película adquirida que se propôs a investigar o potencial de remineralização, potencial de proteção, a perda superficial e a tensão superficial do esmalte após o tratamento com as soluções contendo o copolímero do polimetacrilato. Concluiu- se que a utilização de polímeros formadores de filme, associados ou não a fluoretos, constitui uma abordagem promissora para prevenção da erosão dental. Dentre os polímeros investigados, o copolímero do polimetacrilato é um promissor agente para ser adicionado à produtos de higiene bucal visando a prevenção dos desgastes erosivos(AU)

Erosive wear has been recognized as a frequent condition in recent years, mainly due to changes in the dietary and behavioral habits of the general population. Considering the irreversible nature of this condition, early diagnosis and the adoption of preventive measures are very important. Among them, the addition of polymers to oral care products associated or not with fluorides is a promising alternative, as some polymers have compatibility with dental structures and ability to form a protective film. This study was subdivided into three articles that aimed, through different approaches, to investigate the anti-erosive effect of film- forming polymers, as well as the effect of their association with fluorides. The first article consisted of a literature review about aspects related to the potential use of polymers to prevent dental erosion. The second article consisted of a scanning study to verify the ability to decrease the hydroxyapatite dissolution promoted by solutions containing four polymers (polyoxyrane, hydroxypropyl methylcellulose, pectin and a polymethacrylate copolymer) associated or not with sodium fluoride -F (225 ppm F- ) and sodium fluoride + tin chloride (800 ppm Sn2+ ) -FS. Measurement of the zeta potential of dispersed hydroxyapatite treated with experimental solutions was performed to complement the analysis. The third article consisted of an erosive/rehardening cycling study in the presence of acquired pellicle that aimed to investigate remineralization potential, protection potential, surface loss and surface tension of the enamel after treatment with solutions containing the polymethacrylate. It was concluded that the use of film- forming polymers, associated or not with fluorides, is a promising approach for the prevention of dental erosion. Among the polymers investigated, the polymethacrylate copolymer is a promising agent to be added to oral hygiene products to prevent erosive wear(AU)

Changing bulking agent may require change in injection volume for endoscopic treatment of vesicoureteral reflux

ABSTRACT Introduction: Various bulking agents were utilized for endoscopic correction of VUR. A study reviewing multi-institutional data showed that the amount of injection material has increased over time with the purpose of improving success rates, which also resulted in costs. We noticed an opposite trend in our center since we started using a new bulking agent. The aim of this study was to evaluate evolution of our practice with different bulking agents. Patients and Methods: Records of VUR patients who underwent subureteric injection with polyacrylate polyalcohol copolymer (PPC) and dextronomere hyaluronic acide (DxHA) between 2005 and 2014 were reviewed. Variation of different parameters throughout the study period was evaluated along with the success rate. Success was defined as complete resolution of reflux. Results: A total of 260 patients with 384 refluxing units were included. The success rate was higher in PPC group compared to DxHA group. There was no statistically significant difference between years regarding distribution of VUR grade, body weight, patient height, and age in PPC group. Despite significant reduction in injection volume, success rate did not decrease through the years with PPC. Conclusion: Different bulking agents may require different injection volumes to achieve the same success rate in endoscopic treatment of vesicoureteral reflux. Habits gained with previous experience using other materials should be revised while using a new agent.

Corrosion casting, a known technique for the study and teaching of vascular and duct structure in anatomy / Inyección corrosión, una técnica conocida para el estudio y enseñanza de ductos y estructuras vasculares en anatomía

Teaching and learning anatomy, as a process, has changed. Fresh cadavers were once used as a tool for the student to approach the human body in order to overcome theoretical knowledge and gain applied expertise. Today, techniques such as corrosion casting are known to be a more effective way of achieving optimal results with the students. This paper examines a method to apply this technique to an organ using different polymers. The concentrations for acrylic, epoxy resin, polyester resin, and room temperature vulcanization (RTV) silicone are described, as well as the corresponding diameter of the duct to be injected with each one. A variety of specimens obtained using this technique, their qualities and characteristics are presented. The results of using these procedures while involving the students, showed increased sense of responsibility, dedication and awareness, which led them to take the class more seriously and enjoy the process of learning. Additionally, the specimens left by the students will help future classes reduce the number of specimens needed.

El proceso de aprendizaje y enseñanza en anatomía ha cambiado recientemente, el cadáver fue la primera herramienta que permitía al estudiante una aproximación practica al cuerpo humano, facilitando que este se sobrepusiera al conocimiento teórico adquirido en el aula, y desarrollara experticia aplicada. Hoy en día, técnicas como la inyección corrosión son conocidas por lograr mejores resultados con los estudiantes. Este trabajo presenta un método para aplicar esta técnica a un órgano, mediante el uso de diferentes polímeros. Las concentraciones adecuadas de acrílico, resina epoxica, resina poliéster, y silicona RTV (room temperature vulcanization) son descritas, así como el diámetro sugerido para el uso de cada polímero. Se presenta una variedad de especímenes obtenidos mediante esta técnica, así como sus cualidades y características. Al integrar a los estudiantes en el proceso de creación de los especímenes, estos demuestran mayor sentido de responsabilidad, dedicación y autoconciencia, generando mayor compromiso, y entusiasmo con la clase y el proceso de aprendizaje. Adicionalmente, los especímenes producidos por ellos, serán de gran utilidad para clases a futuro.

Angiogenesis and tumor progression inhibition of cyclooxygenase-2 selective inhibitor celecoxib associated with poly (lactic-co-glycolic acid) in tumor cell line resistant to chemotherapy / Inhibición de angiogénesis y progresión tumoral por inhibidor selectivo de ciclooxigenasa-2 celecoxib asociado con ácido (poli láctico co-glicólico) en línea de células tumorales resistentes a quimioterapia

Although, antineoplastic therapies have now been developed reduction of tumor progression,itis necessarytofind new therapeutic alternatives to suppress angiogenesis.Thus celecoxib (Cx) has been used for its antiangiogenic action in combination with certain polymeric compounds such as poly (lactic co-glycolic acid) (PLGA) acid, which help to improve the bioavailability and avoid effects of long drug administrations. For this purpose we used a murine tumor modelinduced by mammary adenocarcinoma cells resistant to chemotherapy (TA3-MTXR). CX/PLGA inhibits the microvascular density, VEGF expression and cell proliferationinaddition to increased apoptosis (P <0.0001). Cx reduces tumor progression in a concentration of 1000 ppm associated with PLGA, reducing cell proliferation, the presence of VEGF and promoting apoptosis of multiresistant TA3 tumor cells.

Si bien actualmente se han desarrollado terapias antineoplásicas que permiten reducir de cierta manera el avance tumoral, es necesario buscar nuevas alternativas terapéuticas que permitan suprimir la angiogénesis. Es así como el Celecoxib (Cx) ha sido utilizado por su acción antiangiogénica en combinación con algunos compuestos poliméricos, tal como el ácido poli (láctico co-glicólico) (PLGA), el cual ayudaría a mejorar la biodisponibilidad y evitaría efectos derivados de largas administraciones del fármaco. Para tal efecto se ha utilizado un modelo tumoral murino, inducido por células tumorales de adenocarcinoma mamario resistente a la quimioterapia (TA3-MTXR). Los resultados indican que CX/PLGA inhibe la microvascularización, expresión de VEGF y la proliferación celular además del aumento de la apoptosis (P<0,0001). El efecto antitumoral del Cx está bien reportado en la literatura; este sumado a la microencapsulación con PLGA, aportarían un sistema de administración útil, ya que nos otorga una administración sostenida en el tiempo, los cual podría ayudar a mantener los niveles de droga durante un período más prolongado, lo cual sería beneficioso en la terapia tumoral.

Polymeric nanoparticle formulation of Octapeptide (NP-OP): In vitro release and in vivo effect in common marmosets, Callithrix jacchus Linn.

yielded an average particle size of 120 nm with 70% encapsulation-efficiency. In vitro release profile of NP-OP showed sustained release of OP for 21 days. In vivo anti-fertility studies were conducted in marmosets. Results indicated that control animals conceived in the same cycle while two of three treated animals failed to conceive in treatment cycle. The in vivo studies thus corroborate with in vitro release of OP, demonstrating its anti-fertility activity in 66% of animals.

Nanoparticles and microparticles of polymers and polysaccharides to administer fish vaccines

Aquaculture has become an important economic sector worldwide, but is faced with an ongoing threat from infectious diseases. Vaccination plays a critical role in protecting commercially raised fish from bacterial, viral and parasitic diseases. However, the production of effective vaccines is limited by the scarcity of knowledge about the immune system of fish. Improving vaccines implies using antigens, adjuvants and employing methods of administration that are more effective and less harmful to the fish. In this context, in recent year there have studies of methods of encapsulating antigens in matrices of different types to apply in fish vaccines. This work reviews the new methods to improve fish vaccines by encapsulating them in polymers and polysaccharides.

Investigation and comparison of colon specificity of novel polymer khaya gum with guar gum

To investigate the colon specificity of novel natural polymer khaya gum and compare with guar gum. Release profile of tablets was carried out in presence and absence of rat cecal contents. The fast disintegrating core tablets of budesonide, were initially prepared by direct compression technique. Later, these tablets were coated with khaya gum or guar gum. After suitable pre compression and post compression evaluation, these tablets were further coated using Eudragit L-100 by dip coating technique. X-ray images were taken to investigate the movement, location and the integrity of the tablets in different parts of gastro intestinal tract in rabbits. The release profiles revealed that khaya gum or guar gum, when used as compression coating, protected the drug from being released in the upper parts of the gastro intestinal tract to some extent but the enteric coated formulations completely protected the drug from being released in the upper parts of the gastro intestinal tract, and released the drug in the colon by bacterial degradation of gums. It was found that both the polysaccharide polymers exhibited different release profiles in presence and absence of rat cecal contents. However, further enteric coat helped in targeting the drug to colon very effectively. Better dissolution models revealed the colon specificity of polysaccharides and alone can not be used either for targeting the drug to the colon or for sustaining or controlling the release of drug

Biodegradable Polymer Releasing Antibiotic Developed for Drainage Catheter of Cerebrospinal Fluid:In Vitro Results

The authors developed a biodegradable polymer that releases an antibiotic (nalidixic acid) slowly and continuously, for prevention of catheter-induced infection during drainage of cerebrospinal fluid. We investigated the in vitro antibiotic releasing characteristics and bacterial killing effects of the new polymer against E. coli. The novel fluoroquinolone polymer was prepared using diisopropylcarbodiimide, poly (e-capro-lactone) diol, and nalidixic acid. FT-IR, mass spectrometry, and elemental analysis proved that the novel antibacterial polymer was prepared successfully without any side products. Negative MS showed that the released drug has a similar molecular weight (M.W.=232, 350) to pure drug (M.W.=232). In high pressure liquid chromatography, the released drug and drug-oligomer showed similar retention times (about 4.5-5 min) in comparison to pure drug (4.5 min). The released nalidixic acid and nalidixic acid derivatives have antibacterial characteristics against E. Coli, Staphylococcus aureus, and Salmonella typhi, of more than 3 months duration. This study suggests the possibility of applying this new polymer to manufacture drainage catheters that resist catheter-induced infection, by delivering antibiotics for a longer period of more than 1 month.

Efeito do tratamento superficial na resistência adesiva ao cisalhamento de um polímero de vidro / The effect of suface treatment on the shear bond strength of a glass polymer

Investigou-se o efeito do jato de óxido de alumínio e de três substâncias modoficadoras de superfície na resistência adesiva do polímero de vidro Artglass« ao cimento resinoso C&B«. Foram confeccionadas 60 pastilhas de Artglass«, medindo 7,0mm de diâmetro e 5,0mm de altura, e 60 pastilhas medindo 5,0mm de diâmetro e 3,0mm de altura. As pastilhas foram distribuídos em 6 grupos (n=10), e receberam os seguintes tratamentos superficiais: G1- adesivo Alloybond«; G2- agente silano Scotchprimer RelyX« seguido pelo Alloybond«; G3- c&b Liquid«; G4- jato de óxido de alumínio e adesivo Alloybond«; G5- jato e agente silano Scotchprimer« seguido pelo Alloybond«; G6- jato e c&b Liquid«. A cimentação das pastilhas foi realizada com o cimento resinoso C&B« a uma carga de 0,5 kgf. O ensaio de cisalhamento foi realizado em uma Máquina de Ensaio Universal Instron« e após a fratura dos espécimes, as superfícies das pastilhas foram examinadas em lupa com aumento de 20x, para classificação do modo de fratura. Os resultados evidenciaram que os espécimes jateados tiveram os maiores valores de resistência adesiva; e que a apicação do silano Scotchprimer« seguida do Alloybond« gerou valores de resistência adesiva superiores aos outros modoficadores de superfície. Os espécimes não jateados apresentaram 100 por cento de fraturas na interface adesiva, predominando as fraturas no interior do cimento e complexas nos grupos jateados. Conclui-se que o jato , seguido da aplicação do silano Scotchprimer« e do Alloybond«, promoveu a maior resistência adesiva ao cisalhamento entre o Artglass« e o C&B« Cement

Poly (DL-lactide-co-glycolide) microparticles as carriers for antimycobacterial drug rifampicin.

Poly (DL-lactide-co-glycolide) polymers were investigated as carriers for the first line antitubercular drug rifampicin. Different formulations of PLG microparticles viz. porous, non porous and hardened exhibited sustained release of rifampicin up to 7 weeks in vitro. However, hardened PLG microparticles exhibited the most sustained release in vivo in different organs up to 6 weeks. In case of free rifampicin, release was detected in vivo only up to 48 hr. In addition, no hepatotoxicity was observed on a biochemical basis (levels of SGPT, ALP and total bilirubin) in comparison to control animals. Taken together, these results suggest that polymer encapsulated antitubercular drug rifampicin may serve as an ideal therapeutic approach for treatment of tuberculous infections.

Poly (DL-lactide-co-glycolide) based delivery systems for vaccines and drugs.

Current vaccination and drug delivery strategies emphasize on the development of controlled release techniques for persistent and sustained effects. In the recent years, polymer based systems for the delivery of bioactive agents have gained considerable attention due to their marked adjuvanticity, established biodegradability and biocompatibility, excellent mechanical strength and controlled release profiles. This review deals with the potential applications of synthetic polymers mainly PLG polymers in delivery of vaccines and drugs.

Inhibition of three alphaherpesviruses (Herpes simplex 1 and 2 and pseudorabies virus) by heparin, heparan and other sulfated polyelectrolytes

The first step of the herpes virus infection is the attachment to heparan sulfate molecules on the cellular membrane. In order to improve the characterization of this phenomenon, we compared the inhibitory effect of six sulfated polyelectrolytes (PE): heparin, heparan, low molecular wight heparin, chondroitin, dextran and protamine on plaque formation by pseudorabies virus (PRV) were compared. The PE with the highest antiherpetic effect was heparin, followed by dextran sulfate. Heparan sulfate, which has been proposed as the initial receptor of herpes virus on the cell surface showed and effect 100-fold lower than heparin. Comparative inhibition curves of heparin and heparan sulfate against three herpes viruses: herpes simplex virus 1 (HSV-1), HSV 2 and PRV showed similar kinetics of inhibition of plaque formation, suggesting these viruses could share similar cell adsorption mechanisms

Uso del polietilen glicol como tratamiento del estreñimiento asociado al puerperio / Polyethilene glycol as treatment for constipation the puerperium

El estreñimiento es una condición que se asocia con gran frecuencia al período puerperal, el cual causa un importante disconfor en este grupo de pacientes. fueron evaluadas 225 pacientes puérperas, ingresadas en el servicio 9 de la Maternidad "Concepción Palacios" entre nov/93 y abril/95, las cuales fueron divididas en un grupo de estudio (n=113) y un grupo control (n=112). Al grupo de estudio se le administraron dos vasos contentivos de aprox. 250cc de una solución de polietilen Glicol, (elaborada según indicaciones del fabricante), en su primer día de puerperio. Los resultados fueron contrastados con los obtenidos en el grupo control, el cual no recibió ningún tipo de medicación que pudiera modificar su hábito intestinal. En el grupo de estudio 84 pacientes(74,3 por ciento), lograron evacuar en las primeras 24 horas, no registraron a ninguna paciente del grupo control que lograse evacuar en ese mismo lapso (0 por ciento), un 94,7 por ciento del grupo con Polietilen glicol vs 10,7 por ciento del grupo control, lograron evacuar en las primeras 48 horas del puerperio. La consistencia de las heces fue más blanda en el grupo de estudio, y la administración de polietilen glicol no mostró efectos adversos, siendo la única queja registrada, el sabor desagradable

Atualizaçäo em dietas enterais poliméricas no Brasil: I / Up-to-dating in polymeric enteral diets in Brazil: I

Devido ao rápido crescimento de fórmulas enterais industrializadas no mercado brasileiro, tornou-se cada vez mais difícil a seleçäo da melhor fórmula para indicaçäo adequada do suporte nutricional enteral. A análise das características inerentes a cada dieta industrializada disponível e o total conhecimento destas pelos profissionais que atuam nesta área é fundamental para a escolha da fórmula enteral mais adequada. Os autores estudaram dez dietas poliméricas nutricionalmente completas, todas isentas de lactose, as quais foram avaliadas segundo diferentes parâmetros de seleçäo e de dietas: fontes de nutrientes, densidade calórica, complexidade molecular, osmolaridade, forma de apresentaçäo e via de administraçäo