Comparación del confort de dos protectores bucales en jugadores de fútbol americano / Comparing the comfort of two mouth protectors in football players

Los deportes de contacto aumentan el riesgo de traumatismo causando alteraciones funcionales, estéticas y psicológicas. Los protectores bucales son parte del equipo de seguridad que protegen al deportista de estos accidentes, es importante que brinde confort para lograr el mejor rendimiento físico. Objetivo: Comparar el confort de los jugadores de fútbol americano con el uso de protectores prefabricados y protectores personalizados. Metodología: Se realizó un estudio cuasiexperimental, analítico y prospectivo donde se incluyeron 15 jugadores de futbol americano de la Facultad de Estudios Superiores Acatlán, UNAM, que firmaron consentimiento informado. La autora principal de este proyecto fabricó los protectores bucales superiores con hoja de copolímero de etilvinilacetato (EVA) #35. El protector prefabricado fue de silicón. Los jugadores realizaron dos prácticas de entrenamientos donde hicieron 30 minutos de carrera, 15 de estiramiento, 60 de fuerza y destreza en donde requerían de estar en constante comunicación verbal y 30 de cardiovascular en gimnasio (usaron un protector en cada entrenamiento). Se aplicó un cuestionario ­previamente validado por consenso de expertos­ para evaluar el confort en la respiración, lenguaje, náuseas, adaptación, comodidad e hidratación bucal con cada tipo de protector. La información se analizó en el programa SPSS v19.0; se usaron proporciones para las variables cualitativas y medidas de tendencia central y dispersión para las cuantitativas. Para comparar el confort con el uso de ambos protectores se empleó la prueba χ2, con un nivel de significancia p < 0.05. Resultados: La media de edad fue de 20 ± 2 años. Con el protector personalizado 11 jugadores (0.73) refirieron que respiraron y hablaron mejor, sintieron menos náusea 12 (0.80), mejor adaptación 11 (0.73) y mayor comodidad 12 (0.80) que, con el uso de protector bucal prefabricado, encontrando diferencias estadísticamente significativas (p < 0.05) y ocho (0.53) refirió menos hidratación bucal (p > 0.05). Doce (0.80) de los jugadores mencionaron tener mayor confort con el protector personalizado. Conclusiones: Con la metodología empleada y en la muestra estudiada, el uso de un protector bucal personalizado fabricado con hoja de copolímero de etilvinilacetato (EVA) #35 ofrece una mejor adaptación y comodidad, después de dos prácticas de entrenamiento (AU)

The contact sports, increase the risk of trauma causing functional, aesthetic and psychological alterations, mouth guards are part of the safety equipment that protects the athlete from this kind of accidents, it is also important that the mouth guard had to provides comfort, for achieve a best physical performance. Objective: Make the comparison with the comfort of American football players with the use of prefabricated protectors and customized protectors. Method: A quasi-experimental, analytical and prospective study was carried out, including 15 American football players from the Facultad de Estudios Superiores Acatlán, UNAM, who signed an informed consent. The lead author of this project manufactured the upper mouth guards with ethylvinylacetate (EVA) #35 copolymer foil. The prefabricated protector was made of silicone. The players performed two practice sessions where they did 30 minutes of running, 15 of stretching, 60 of strength and skill where they required being in constant verbal communication and 30 of cardiovascular in a gymnasium (they used a protector in each training). A questionnaire ­previously validated by expert consensus­ was applied to evaluate comfort in breathing, language, nausea, adaptation, comfort and oral hydration with each type of protector. The information was analyzed in the program SPSS v19.0; proportions were used for the qualitative variables and measures of central tendency and dispersion for the quantitative ones. To compare the comfort with the use of both protectors the test χ2 was used, with a level of signifi cance p < 0.05. Results: The mean age was 20 ± 2 years. With the personalized protector, 11 players (0.73) reported that they breathed and spoke better, feeling less nausea 12 (0.80), better adaptation 11 (0.73) and greater comfort 12 (0.80) than with the use of prefabricated mouth guards, fi nding statistically signifi cant diff erences (p < 0.05) and 8 (0.53) reported less oral hydration (p > 0.05). 12 (0.80) of players mentioned having more comfort with the custom protector. Conclusions: The use of a personalized mouth guard off ers better fi t and comfort made with sheet copolymer of ethylvinylacetate, after two training practices (AU)

Simultaneous Determination of Furan and Vinyl Acetate in Vapor Phase of Mainstream Cigarette Smoke by GC-MS

ABSTRACT A simple and sensitive method for simultaneous determination of furan and vinyl acetate (VA) in vapor phase of mainstream cigarette smoke with cold trap and gas chromatography-mass spectrometry (GC-MS) was developed. A Cambridge filter pad (CFP) was placed in front of the impingers of smoking machine to remove the particle phase from cigarette smoke. Furan and VA in vapor phase of mainstream cigarette smoke were collected in two impingers connected in series by filled with methanol at -78°C. The solutions were added with deuterium-labeled furan-d4 and VA-d6 as internal standards and analyzed by GC-MS. The results showed that the calibration curves for furan and VA were linear (r2 > 0.9995) over the studied concentration range. The intra- and inter-day precision values for furan and VA were <7.07% and <9.62%, respectively. The extraction recoveries of furan and VA were in the range of 94.5-97.7% and 92.3-94.9%, respectively. Moreover, the limits of detection for furan and VA were 0.028 µg mL-1 and 1.3 ng mL-1, respectively. The validated method has been successfully applied to determine the emissions of furan and VA in the vapor phase of mainstream cigarette smoke under International Organization for Standardization (ISO) and Canadian Intense (CI) smoking regimen.

Caracterización del ambiente físico en viviendas Petrocasas en el Asentamiento Simón Bolívar de Cienfuegos (2008-2009) / Characterization of the physical environment in petrohouses from the village of Simón Bolívar in the province of Cienfuegos (2008-2009)

En varios asentamientos del país se han construido viviendas Petrocasas de policloruro de vinilo, relleno con hormigón sobre balsa y cubierta de lámina de aluminio revestida de papel asfalto por ambas caras. El policloruro de vinilo como material de construcción resulta controversial en relación a sus efectos en la salud. Con el objetivo de caracterizar desde el punto de vista sanitario el ambiente físico en viviendas Petrocasas de Cienfuegos, fue conducido un estudio descriptivo en dos semanas seleccionadas de las estaciones seca y húmeda de 2008 y 2009. Se monitoreó factores de riesgo físico en una muestra de 6 viviendas seleccionadas según la opinión de expertos, del total de las 104 viviendas del asentamiento según su ubicación en las filas de viviendas: centro, culata de fila y fachada. Se estudió el ruido, componente magnético del campo electromagnético de baja frecuencia, iluminación natural, artificial, microclima y penetración del viento. La evaluación del monitoreo se efectuó por descriptores estadísticos, modelos de regresión, varianza y espectro de potencia bivariado con los paquetes estadísticos: SPSS v. 17,0 y Statistica v. 8,0. Durante la estación seca, la temperatura del aire es mayor en la habitación principal de viviendas con fachada al sur. En ambas estaciones, las temperaturas y humedades relativas de las viviendas son más altas que en la intemperie. Las cubiertas y paredes muestran calentamientos ante el asoleamiento. Los coeficientes de iluminación natural presentan elevadas reflexiones. Los valores del campo electromagnético son bajos. En la estación seca los niveles sonoros reflejan una contaminación acústica moderada. Concluimos que el microclima en el interior de las viviendas durante el día es inconfortable(AU)

Petrohouses have been built in several villages in the country. These houses are made of polyvinyl chloride, filled with raft concrete and covered with aluminum sheets coated with asphalt paper on both sides. The health effects of polyvinyl chloride as a construction material is a matter of controversy. With the purpose of carrying out a health characterization of the physical environment in Cienfuegos petrohouses, a descriptive study was conducted during two weeks selected from the dry and wet seasons of 2008 and 2009. Physical risk factors were monitored in a sample of 6 houses selected on the basis of expert opinion, of the total 104 houses in the village, according to their location in the rows: front, mid and end positions. The variables studied were noise, magnetic component of the low frequency electromagnetic field, natural and artificial lighting, microclimate and wind penetration. Monitoring was evaluated with statistical descriptors, regression models, variance and bivariate power spectrum, with the statistical software SPSS v. 17.0 and Statistica v. 8.0. In the dry season, air temperature is higher in the main room of houses with facades facing the south. In both seasons, temperature and relative humidity values are higher inside the houses than outside. Covers and walls heat up when hit by the sun. Natural lighting coefficients show high reflection values. Electromagnetic field values are low. In the dry season, sound levels show moderate acoustic contamination. It is concluded that the microclimate inside houses during the day is uncomfortable(AU)

Study on solid dispersion of copovidone-based tanshinone II(A) / 中国中药杂志

<p><b>OBJECTIVE</b>To apply PVP-S630 in the preparation of tanshinone II(A) (TS II(A)) solid dispersion, in order to improve its dissolution in vitro and reduce the moisture absorption of the solid dispersion.</p><p><b>METHOD</b>Tanshinone II(A) solid dispersion was prepared by spray drying method. Such analytical methods as SEM, DSC, XRD were used to characterize their phases and detect their dissolution, moisture absorption and stability.</p><p><b>RESULT</b>In the solid dispersion prepared with tanshinone II(A) and copovidone with proportion of 1:10, tanshinone II(A) was scattered on the surface of the carrier in the amorphous form, with a dissolution in vitro up to 100% at 0.5 h and a lower moisture absorption than PVP-K30 solid dispersion prepared with the same proportion. After a three-month accelerated stability test, it showed no significant change in drug dissolution and content.</p><p><b>CONCLUSION</b>The solid dispersion prepared with copovidone as the carrier can significantly improve the dissolution of tanshinone II(A), with a relatively low moisture absorption and high stability, thereby having a good prospect of application.</p>

Study on Xinyueshu spray drying assisted with copovidone and its effect on powder property / 中国中药杂志

To study the application characteristics of copovidone (PVP-S630) in Xinyueshu extracts during the spray drying process, and its effect on such pharmaceutical properties as micromeritics and drug release behavior. PVP-S630 was added into Xinyueshu extracts to study on the spray drying, the effect of different dosages of PVP-S630 against the wall sticking effect of the spray drying, as well as the power property of Xinyueshu spray drying power and the dissolution in vitro behavior of the effective component of hyperoside. The results showed that PVP-S630 revealed a significant anti-wall sticking effect, with no notable change in the grain size of the spray drying power, increase in the fluidity, improvement in the moisture absorption and remarkable rise in the dissolution in vitro behavior of hyperoside. It was worth further studying the application of PVP-S630 in spray drying power of traditional Chinese medicine.

Washout resistance of fast-setting pozzolan cement under various root canal irrigants

OBJECTIVES: Fast-setting pozzolan cement (Endocem, Maruchi) was recently developed. The aim of this study was to investigate the effects of various root canal irrigants on the washout of Endocem in comparison to the previously marketed mineral trioxide aggregate (ProRoot; Dentsply) in a furcal perforation model. MATERIALS AND METHODS: ProRoot and Endocem were placed into acrylic molds on moist Oasis. Each mold was then immediately exposed to either physiologic saline, 2.5% sodium hypochlorite (NaOCl), or 2% chlorhexidine (CHX) under gentle shaking for five minutes. Washout testing was performed by scoring scanning electron microscope (SEM) images. RESULTS: Endocem exhibited higher washout resistance compared to ProRoot, especially in the NaOCl group. CONCLUSIONS: These results suggest that Endocem can be considered a useful repair material for furcal perforation, especially in a single-visit scenario.

Effect of five brands of latex gloves on the setting time of polyvinyl siloxane putty impression materials.

Addition silicone impression materials have been used as impression material for more than 20 years. Although they are among the most expensive impression materials, they became popular during the past decade as they have excellent physical properties. Prevention of infection is an important aspect in dental treatment since dental professionals are routinely exposed to the wide variety of microorganisms present in saliva. Gloves are the most common protective measure used during dental treatment. The gloves are mostly made of latex. In this study, we examine how the setting time of three types polyvinyl putty materials were affected by the use of five different brands of latex gloves and one brand of vinyl gloves. Each material was first mixed without wearing gloves according to the manufacturer's instructions. After the stipulated mixing time, the setting time was measured using the Vicat needle. The setting time is measured from the time of mixing till the time that the needle does not produce any indentation on the surface of the material. The putty material was then mixed with gloved hands (using the five different brands of latex gloves in turn) and the setting time was measured. Then the material was mixed with washed gloved hands, and the setting time was measured again. Finally, the material was mixed with vinyl gloved hands and the setting time was measured. The following conclusions were drawn from the study: Reprosil™ and Express™ showed significant variation in the setting time with the latex gloved hands. There was no significant variation in the setting time when material was mixed with unwashed vs washed gloved hands. Vinyl gloves did not significantly affect the setting time of any of the putty impression materials.

Coronal microleakage of four temporary restorative materials in Class II-type endodontic access preparations

OBJECTIVES: The purpose of this study was to evaluate the microleakage of 4 temporary materials in teeth with Class II-type endodontic access preparations by using a glucose penetration model. MATERIALS AND METHODS: Glucose reaction test was performed to rule out the presence of any reaction between glucose and temporary material. Class II-type endodontic access preparations were made in extracted human premolars with a single root (n = 10). Each experimental group was restored with Caviton (GC), Spacer (Vericom), IRM (Dentsply-Caulk), or Fuji II(GC). Microleakage of four materials used as temporary restorative materials was evaluated by using a glucose penetration model. Data were analyzed by the one-way analysis of variance followed by a multiple-comparison Tukey test. The interface between materials and tooth were examined under a scanning electron microscope (SEM). RESULTS: There was no significant reaction between glucose and temporary materials used in this study. Microleakage was significantly lower for Caviton and Spacer than for Fuji II and IRM. SEM observation showed more intimate adaptation of tooth-restoration interfaces in Caviton and Spacer than in IRM and Fuji II. CONCLUSIONS: Compared to IRM and Fuji II, Caviton and Spacer can be considered better temporary sealing materials in Class II-type endodontic access cavities.

The effects of short-term application of calcium hydroxide on dentin fracture strength / 대한치과보존학회지

OBJECTIVES: This in vitro study investigated whether short-term application of calcium hydroxide in the root canal system for 1 and 4 wk affects the fracture strength of human permanent teeth. MATERIALS AND METHODS: Thirty two mature human single rooted mandibular premolars in similar size and dentin thickness without decay or restorations were hand and rotary instrumented and 16 teeth vertically packed with calcium hydroxide paste and sealed coronally with caviton to imitate the endodontic procedure and the other 16 teeth was left empty as a control group. The apicies of all the samples were sealed with resin, submerged in normal saline and put in a storage box at 37degrees C to mimic the oral environment. After 1 and 4 wk, 8 samples out of 16 samples from each group were removed from the storage box and fracture strength test was performed. The maximum load required to fracture the samples was recorded and data were analysed statistically by the two way ANOVA test at 5% significance level. RESULTS: The mean fracture strengths of two groups after 1 wk and 4 wk were similar. The intracanal placement of calcium hydroxide weakened the fracture strength of teeth by 8.2% after 4 wk: an average of 39.23 MPa for no treatment group and 36.01 MPa for CH group. However there was no statistically significant difference between experimental groups and between time intervals. CONCLUSIONS: These results suggest that short term calcium hydroxide application is available during endodontic treatment.

Fenómeno de Raynaud por exposición a cloruro de vinilo / Raynaud's phenomenon secondary to vinyl chloride exposure

El policloruro de vinilo (PVC) es el polímero que ocupa el tercer puesto en el mercado de producción de plásticos a nivel mundial. Como consecuencia de la exposición crónica, los operarios pueden desarrollar cambios óseos degenerativos, Raynaud, trastornos circulatorios en extremidades, trombocitopenia y lesiones cutáneas semejantes a esclerodermia; esto se conoce como “enfermedad por cloruro de vinilo”. Presentamos un paciente masculino de 24 años de edad que presenta fenómeno de Raynaud, cefaleas, malestar en manos y pies, sensación de frío, fatiga y pérdida de apetito asociado a exposición a policloruro de vinilo. El estudio de la microcirculación cutánea periungueal por videocapilaroscopía muestra alteraciones estructurales y funcionales características. Se recomienda un seguimiento multidisciplinario estricto de los trabajadores expuestos a PVC.

Enzyme-catalyzed synthesis of ASGPR ligand-targeted modifier in non-aqueous medium / 药学学报

The asialoglycoprotein receptor (ASGPR) was used to mediate drug carrier for hepatic targeted drug delivery, this article showed the enzyme-catalyzed esterification of galactose and vinyl stearate and a kind of ASGPR ligand-targeted which was used to insert the surface of liposome has been synthesized. The structure of product has been confirmed by TLC, ESI-MS and 1H NMR. The factors of types and quantity of enzyme, organic solvents, molar ratio of substrate, temperature and time of reaction have been studied. Results showed when using acetone as reaction medium, the quantity of Novozym 435 immobilized lipase was 30 mg mL(-1), molar ratio of galactose to vinyl stearate was 1:5, and reacted at 60 degrees C for 12 h, the transformation of vinyl stearate reached more than 70%. This study provides a novel and efficient route to the synthesis of ligand-targeted modifier.

Two approaches to discovering and developing new drugs for Chagas disease

This review will focus on two general approaches carried out at the Sandler Center, University of California, San Francisco, to address the challenge of developing new drugs for the treatment of Chagas disease. The first approach is target-based drug discovery, and two specific targets, cytochrome P450 CYP51 and cruzain (aka cruzipain), are discussed. A "proof of concept" molecule, the vinyl sulfone inhibitor K777, is now a clinical candidate. The preclinical assessment compliance for filing as an Investigational New Drug with the United States Food and Drug Administration (FDA) is presented, and an outline of potential clinical trials is given. The second approach to identifying new drug leads is parasite phenotypic screens in culture. The development of an assay allowing high throughput screening of Trypanosoma cruzi amastigotes in skeletal muscle cells is presented. This screen has the advantage of not requiring specific strains of parasites, so it could be used with field isolates, drug resistant strains or laboratory strains. It is optimized for robotic liquid handling and has been validated through a screen of a library of FDA-approved drugs identifying 65 hits.

Microleakage of endodontic temporary restorative materials under dynamic loading / 대한치과보존학회지

The purpose of this study was to compare the sealing abilities of four endodontic temporary restorative materials using a methylene blue dye penetration test under dynamic loading. Standardized access cavities were prepared in forty-four intact human permanent molar teeth, and the cavities were restored with Caviton, MD-Temp, IRM, or ZOE. After thermocycling, an intermittent load of 98 N at 1 Hz was applied for 1,000 cycles to the long axis of the functional cusp of each of the teeth, which were immersed in a 1% methylene blue solution. The teeth were split in half, and the linear depth of dye penetration was evaluated according to the criteria. The results were analyzed using one-way ANOVA (p = 0.05) and Duncan's multiple range test. The results demonstrated that Caviton and MD-Temp showed significantly lower microleakage than IRM and ZOE. It was concluded that Caviton and MD-Temp exhibited better sealing ability than IRM and ZOE under dynamic loading.

Polymerization shrinkage, hygroscopic expansion and microleakage of resin-based temporary filling materials / 대한치과보존학회지

The purpose of this study was to measure the polymerization shrinkage and hygroscopic expansion of resin-based temporary filling materials and to evaluate microleakage at the interface between the materials and cavity wall. Five resin-based temporary filing materials were investigated: Fermit (Vivadent), Quicks (Dentkist), Provifil (Promedica), Spacer (Vericom), Clip (Voco). Caviton (GC) was also included for comparison. Polymerization shrinkage of five resin-based temporary filling materials was measured using the bonded disc method. For the measurement of hygroscopic expansion, the discs of six cured temporary filling materials were immersed in saline and a LVDT displacement sensor was used to measure the expansion for 7 days. For estimating of microleakage, Class I cavities were prepared on 120 extracted human molars and randomly assigned to 6 groups of 20 each. The cavities in each group were filled with six temporary filling materials. All specimens were submitted to 1000 thermo-cycles, with temperature varying from 5degrees C/55degrees C. Microleakage was determined using a dye penetration test. The results were as follows: 1. Fermit had significantly less polymerization shrinkage than the other resin-based temporary filling materials. Fermit (0.22 %) < Spacer (0.38 %) < Quicks (0.64 %), Provifil (0.67 %), Clip (0.67 %) 2. Resin-based temporary filling materials showed 0.43 - 1.1 % expansion in 7 days. 3. Fermit showed the greatest leakage, while Quicks exhibited the least leakage. 4. There are no correlation between polymerization shrinkage or hygroscopic expansion and microleakage of resin-based temporary filling materials.

The Effect of Temporary Filling Materials on The Adhesion between Dentin Adhesive-coated Surface and Resin Inlay / 대한치과보존학회지

The purpose of this research was to compare the microtensile bond strength of resin coated surface and resin inlay according temporary filling materials prior to applying self-adhesive resin cement. Caviton(GC, Japan), Provifil(Promedica, Neumunster, Germany), Provifil(Promedica, Neumunster, Germany) & petrolatum, and Eugenol-based cement, Tembond(Kerr, Orange CA, USA) were used as temporary filling materials. After fabrication of Tescera(Bisco, Schamburg IL, USA), it was bonded with a self-adhesive resin cement, Rely X unicem(3M, St. Paul. Minn, USA). After this procedure, the microtensile bond strength was measured and it was analyzed through one-way ANOVA and Duncan test(p<0.05). Caviton(GC, Tokyo, Japan) showed statistical difference except for the control(group I) and the saliva(group II)(p<0.05). Provifil(group IV), Provifil & petroneum(group V), Tembond(group VI) had lower microtensile bond strength.

The drug release properties of poly (acrylamide-co-itaconate-vinylbenzylglycosylallylamide) hydrogels / 生物医学工程学杂志

Sugar-containing monomer vinylbenzylglycosylallyamide (VBG) was synthesized by vinylbenzyl amine and delta-gluconolactone in dimethylformamide(DMF) solution. The sugar-based hydrogel was prepared by free radical crosslinking copolymerization of VBG, itaconic acid (IA) and acrylamide (AM). The release properties of Aspirin from xerogels matrices and from hydrogel in different pH solutions and different concentration NaCl solutions were studied respectively. The release mechanism of Aspirin was further confirmed by evaluating the n value in Peppas equation. The results indicated that the drug release increased with the increase of pH values and with the decrease of NaCl concentration.

Estudo evolutivo da anatomia das artérias coronárias em espécies de vertebrados com técnica de moldagem em acetato de vinil (vinilite) / Study of evolutive coronary arteries anatomy in vertebrates using vinyl acetate technique

No presente trabalho foram produzidos 30 moldes anatômicos de corações de vertebrados, visando contribuir para o estudo das artérias coronárias direita e esquerda de diferentes espécies: peixes, anfíbios, répteis, aves e mamíferos. Os corações foram injetados com acetato de vinil, submetidos a corrosão e semicorrosão pelo ácido clorídrico, a fim de evidenciar o padrão anatômico apresentado pelas artérias coronárias no tocante à evolução das espécies e adaptações morfológicas (estrutura e arquitetura). Com base na morfologia das peças estudadas foram obtidas as seguintes conclusões: a técnica utilizando acetato de vinil, associada à corrosão, mostrou-se eficaz na produção de modelos de coração de diferentes espécies, apresentando detalhamento capaz de permitir visibilização dos ramos colaterais, quando existentes; o número de estruturas e a complexidade vascular cardíaca aumenta na medida em que os seres evoluem na escala zoológica. No réptil iguana iguana foi encontrado ventrículo duplo com tríplice via de saída, como único padrão evolutivo da anatomia dos ventrículos e grandes vasos da base ainda não descrito como cardiopatia congênita em humanos

Synthesis and characterization of noncrosslinked and crosslinked poly [vinyl alcohol-co-crotonc acid] hydrogels

The aim of this work was to investigate the possibility of combining hydrophilic [VAL] monomer with crotonic acid [CA] monomer and to explore their potential for drug delivery. Six noncrosslinked poly[vinyl acetate-co-crotonic acid] [VAC/CA] samples 50:50 to 95:05 mole% were prepared. The monomer feed ratio affects the molecular weight and the polymerization hindered by increasing the CA traction in the monomer mixture. This is most probably due to differences in reactivity ratios. All the samples were hydrolysed in methanolic KOH solution. Salt form was converted into acid form by adding acetic acid. In poly[vinyl alcohol-co-crotonic acid] [VAL/CA] polymers, the OH and the COOH groups seem to be partially involved in a lactonized form. By increasing the COOH groups, the amount of OH groups reduced through lactone ring formation. The COOH groups are few in numbers and might be at scattered positions in the chain, making the gels unable to show pH-sensitivity. One sample of VAL/CA containing monomeric composition [VAC/CA 90: 10] was crosslinked with glutaraldehyde, with various crosslinking ratios. A remarkable effect of crosslinking ratio was observed on swelling and phenazone release

Ph-sensitive noncrosslinked poly [vinyl alcohol-co-acrylic acid] hydrogels for site specific drug delivery

A study has been made on the possibility of combining anionic monomers with hydrophilic vinyl alcohol monomer and to explore their potential for colonic drug delivery. Vinyl acetate [VAC] and acrylic acid [AA] monomers were polymerized and the effect of monomer ratio on copolymer composition was studied. It was observed that by increasing the VAC fraction in ratios higher than that of AA in the monomeric mixture, the process of polymerization was hindered. A big difference in reactivity ratio affects the polymerization process and copolymer composition. Poly[vinyl acetate-co-acrylic acid] polymer was hydrolysed in methanolic potassium hydroxide [KOH] solution. Salt form was converted into acid form by adding hydrochloric acid [HCI]. In hydrolysed copolymers it was observed that by increasing the AA, the systems were indeed pH-sensitive but no effect of free hydroxyl [OH] groups was observed, because OH groups were linked in the lactone rings with the dominent carboxylic COOH groups. Monomer ratio affects the swelling and drug release properties of the hydrogels. Swelling shifts to lower pH values by increasing the acrylic acid traction in the copolymer. Two samples of V AL/AA of different monomer ratio were loaded with betamethasone. The drug release from these samples is dependent on the acrylic acid fraction in the copolymer and on the pH of the medium. Thus it has been shown that it is possible to prepare pH-sensitive systems for well accepted monomers without using crosslinking agents

Estudo antômico do retalho lateral do braço / Anatomical study of the lateral arm flap

Com o objetivo de estudar a anatomia do retalho lateral do braço, foram realizadas dissecçoes de 45 membros superiores direitos de 45 cadáveres. A idade variou de 25 a 81 anos. Todos eram do sexo masculino. Eles foram divididos em três grupos de estudo, de acordo com a metodologia empregada, que variou conforme a soluçao contrastante: azul de metileno, vinil/tinta e óxido de chumbo. Os dados obtidos foram relacionados com valores antropométricos individuais. As dimensoes do retalho, emergência do primeiro vaso septal, perfuraçao do septo intermuscular lateral pelo feixe vasculonervoso puderam ser estimuladas por meio de adequaçoes cujas variáveis eram o comprimento e perímetro do braço. Presença de anastomose vascular distal do retalho, da artéria colateral radial posterior com a artéria residual, foi constatada em apenas 10 por cento dos casos estudados. Presença de pedículo vascular duplicado ao nível da perfuraçao do septo intermuscular lateral do braço foi observada em 10 por cento dos casos; contudo, apenas um único pedículo nutria o retalho. Registrou-se divisao constante da artéria colateral em anterior e posterior, divisao da artéria colateral radial posterior em dois ramos em 100 por cento dos casos, com um ramo para porçao distal do úmero e músculos tríceps. O nervo cutâneo lateral inferior do braço perfurou o tríceps em 30 por cento dos casos. O diâmetro da artéria colateral radial ao nível da perfuraçao do septo intermuscular lateral do braço mediu em média 1,5mm. O padrao fasciocutâneo do retalho mostrou ser constante. Concluiu-se da presença de variaçoes da anatomia vascular e trajeto do nervo cutâneo lateral inferior do braço, que a estimativa das dimensoes do retalho deve considerar dados antropométricos individuais; o padrao fasciocutâneo e a vascularizaçao do segmento ósseo do úmero e músculo tríceps garantem a utilizaçao do retalho do braço em sua forma composta.