Estudo in vitro das alterações morfológicas da superfície de raízes submetidas à apicectomia e írradiadas com laser de Nd:YAG

Introduction: success rates of apical surgery are variable, and there are several causes of failure related in the literature. Among them, permeability of exposed dentin at the apical surface after apicoectomies has been receiving much attention, Nd: YAG laser irradiation can decrease this permeability, but its effects on root surface are not completely known. Objectives: evaluate morphological alterations of apical surface, specially surface smoothness, after Nd: YAG non contact laser irradiation, in different powers, in vitro. Material and Methods: thirty extracted human cuspids, maintained in distilled water had its crowns removed, and were endodontically treated in standard technique. Apicoectomy performed, removing 4 mm most apical of roots, using handpiece. Teeth were divided in three groups of 10 each. Half of the area of each apical surface was irradiated with Nd:YAG laser in non contact mode, for 30 seconds. Three different powers were used- three groups of 10 each. Half of the area of each apical surface was irradiated.Introdução: os índices de sucesso da cirurgia apical são variáveis, sendo diversas as causas de fracasso relatadas na literatura. Dentre elas, a permeabilidade da dentina exposta na superfície apical após apicectomias tem recebido grande atenção. A irradiação com laser de Nd:YAG é capaz de diminui-la, mas não se conhece completamente seu efeito sobre a superfície de corte apical. Proposição: avaliar as alterações morfológicas da superfície de corte apical promovidas pela irradiação com laser de Nd:YAG sem contato, em diferentes potências, in vitro. Metodologia: trinta dentes caninos humanos, após a remoção de suas coroas, receberam tratamento endodôntico e tiveram seus quatro milímetros mais apicais ressecados com fresa cirúrgica em baixa rotação, sob irrigação. Foram divididos em três grupos de dez dentes cada. A metade da área de suas superfícies apicais foi irradiada com laser de Nd:YAG, à distância de dois milímetros entre a extremidade da fibra óptica e o tecido alvo, durante 30 segundos. As potências médias empregadas foram 1,6 W, 2,0 W e 2,4 W, variando de acordo com os respectivos grupos. As raízes foram estudadas com MEV. Resultados: áreas de fusão e derretimento da superfície de smear layer foram observadas nas superfícies irradiadas, que se mostraram mais compactas pela diminuição da porosidade. Crateras e áreas de danos térmicos foram de observação eventual. Os efeitos da irradiação não foram homogêneos ao longo das superfícies. Conclusões: o laser de Nd:YAG, aplicado sem contato nas condições descritas, foi capaz de promover fusão e recristalização da smear layer nas superfícies de corte de apicectomias

Analysis of weed community changes and their determining factors in no-tillage systems

El sistema de siembra directa implica el uso conjunto de una serie de prácticas de manejo que determinan cambios adaptativos en la comunidad de malezas. Distintos sistemas de laboreo del suelo generan diferentes condiciones de luz, temperatura y humedad suficientes para alterar la emergencia y establecimiento de numerosas especies de malezas. El sistema de siembra directa requiere un empleo diferente de herbicidas y puede disminuir la eficiencia de los mismos. Estos cambios en el control químico pueden contribuir a explicar modificaciones en la composición de la flora. El impacto de los sistemas de siembra directa varía marcadamente según regiones y especies de malezas consideradas y en Argentina en particular, la información sobre el comportamiento de las comunidades de malezas en distintos sistemas de labranza es reducida. Si bien esta revisión está centrada en las principales prácticas agrícolas y especies de malezas comunes en la pampa húmeda argentina, debido a la falta de información específica en muchos aspectos, se ha recurrido también a investigaciones relevantes en otras áreas. La siembra directa contínua conduce en la mayoría de los casos revisados a reducciones en la abundancia de muchas malezas latifoliadas anuales en el largo plazo. La excepción son las especies cuyos propágulos son transportados por el viento. Las poblaciones de gramíneas anuales, en cambio, son más abundantes en siembra directa con respecto a sistemas de laboreo convencional. Las malezas perennes como grupo no están asociadas a ningún sistema de labranza. El conocimiento de la influencia de la siembra directa sobre la flora de malezas contribuirá a lograr un control más confiable y un adecuado manejo del ambiente en la región.No-tillage systems imply a series of agricultural practices acting together with significant consequences on weed flora adaptations. Absence of tillage produces fundamental habitat changes commonly causing shifts in composition and abundance of weeds. Type of tillage alters light, temperature and moisture conditions sufficiently to modify emergence and establishment of many weeds species. No-tillage systems leads to different herbicide use and reductions in their performance and may result in shifts in species composition. The impact of no-tillage systems on weed communities varies greatly among regions and weed species. While the focus of this review is on the principal agricultural practices and weeds common in the Humid Pampa (Argentina), much especific research is lacking in the country, thus, this paper also draws information from relevant research elsewhere. In most papers reviewed, annual broadleaf weeds are more abundant in no-tillage systems, the exception being wind-disseminated species. Grassy weeds show greater populations in no-till while perennials are not associated to any tillage system. Better knowledge of no-tillage influence on weed flora will contribute to more reliable weed control and adequate environmental management in the region.Facultad de Ciencias Agrarias y Forestale

Analysis of weed community changes and their determining factors in no-tillage systems

El sistema de siembra directa implica el uso conjunto de una serie de prácticas de manejo que determinan cambios adaptativos en la comunidad de malezas. Distintos sistemas de laboreo del suelo generan diferentes condiciones de luz, temperatura y humedad suficientes para alterar la emergencia y establecimiento de numerosas especies de malezas. El sistema de siembra directa requiere un empleo diferente de herbicidas y puede disminuir la eficiencia de los mismos. Estos cambios en el control químico pueden contribuir a explicar modificaciones en la composición de la flora. El impacto de los sistemas de siembra directa varía marcadamente según regiones y especies de malezas consideradas y en Argentina en particular, la información sobre el comportamiento de las comunidades de malezas en distintos sistemas de labranza es reducida. Si bien esta revisión está centrada en las principales prácticas agrícolas y especies de malezas comunes en la pampa húmeda argentina, debido a la falta de información específica en muchos aspectos, se ha recurrido también a investigaciones relevantes en otras áreas. La siembra directa contínua conduce en la mayoría de los casos revisados a reducciones en la abundancia de muchas malezas latifoliadas anuales en el largo plazo. La excepción son las especies cuyos propágulos son transportados por el viento. Las poblaciones de gramíneas anuales, en cambio, son más abundantes en siembra directa con respecto a sistemas de laboreo convencional. Las malezas perennes como grupo no están asociadas a ningún sistema de labranza. El conocimiento de la influencia de la siembra directa sobre la flora de malezas contribuirá a lograr un control más confiable y un adecuado manejo del ambiente en la región.No-tillage systems imply a series of agricultural practices acting together with significant consequences on weed flora adaptations. Absence of tillage produces fundamental habitat changes commonly causing shifts in composition and abundance of weeds. Type of tillage alters light, temperature and moisture conditions sufficiently to modify emergence and establishment of many weeds species. No-tillage systems leads to different herbicide use and reductions in their performance and may result in shifts in species composition. The impact of no-tillage systems on weed communities varies greatly among regions and weed species. While the focus of this review is on the principal agricultural practices and weeds common in the Humid Pampa (Argentina), much especific research is lacking in the country, thus, this paper also draws information from relevant research elsewhere. In most papers reviewed, annual broadleaf weeds are more abundant in no-tillage systems, the exception being wind-disseminated species. Grassy weeds show greater populations in no-till while perennials are not associated to any tillage system. Better knowledge of no-tillage influence on weed flora will contribute to more reliable weed control and adequate environmental management in the region.Facultad de Ciencias Agrarias y Forestale

Differential susceptibility of Conyza bonariensis biotypes to glyphosate and ALS-Inhibiting herbicides in Argentina

The aim of this study was to compare control of three stages biotypes (rosette, bolting, and repro- ductive stage) of Conyza bonariensis glyphosate susceptible biotype (S) and tolerant biotype (T) to glyphosate with glyphosate and mixtures of acetolactate synthase (ALS)-inhibiting. For glyphosate, the dose-response curves confirmed that injury of the biotype T relative to biotype S was signifi- cantly lower for both rosette and bolting stages. Resistance index (RI) for this herbicide was approximately 4 for both weed stages. At bolting, for both biotypes doses much higher than the recommended dose were required. For acetolactate synthase (ALS)-inhibiting herbicides, at the rosette stage, control of both biotypes was excellent with doses significantly lower than the recommended rate. All herbicides within this group showed a very low I50 relative to the recommended rate. These results indicate that biotypes difficult to control with glyphosate at the rosette and bolting stage may be controlled using acetolacte synthase (ALS)-inhibiting herbicides. Control for the reproductive stage was poor. A management program based on the combination of glyphosate with pre- and post-emergence acetolactate synthase (ALS) herbicides may be effective to control the weed.EEA ParanáFil: Puricelli, Eduardo Carlos Jose Maria. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Faccini, Delma Edith. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Metzler, Marcelo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ArgentinaFil: Torres, Patricia Susana. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentin

Estudo histológico do polímero poliuretano da mamona implantado no ângulo mandibular de ratos

Ricinoleic acid polyurethane polymer behaviour, implanted subperiostic in rat's mandibular angles was studied. liventy Rattus novergicus (Alhinus rodentia mammalia, cepa Wistar) were divided in for groups of five animals each. The polymer polyurethane, added of calcium carbonate, was implanted at mandibular angle of them. One animal from and 90 days after surgery. Histological examination showed the stability of the implant, the almost total absence of inflammatory response, the fibrous capsule formed surrounding the implant, and bone neoformation. According the experimental model, we concluded that the subperiostic implanted ricinoleic acid polyurethane polymer did not unleash a significant later inflammatory reaction, it has took to the development of a districted fibrous capsule, with evolution for bone neoformation. Signals of rejection, exposition or expel of the implant were not registered.Este estudo analisou o comportamento do polímero poliuretano da mamona implantado em leito subperióstico em ângulos mandibulares de ratos. Vinte Rattus novergicus (var. Albinus rodentia mammalia, cepa Wistar) foram divididos em quatro grupos de cinco animais. O polímero poliuretano da mamona, com adição de carbonato de cálcio, foi implantado no bordo inferior da mandíbula dos mesmos. Em cada grupo, um animal correspondeu ao controle, tendo sido submetido à cirurgia sem a colocação do implante. Os animais foram sacrificados após 15, 30, 60 e 90 dias pós-operatórios. Ao exame histológico, em cortes corados com hematoxilina e eosina (HE), observou-se a estabilidade do implante, a ausência significativa de reação inflamatória, a formação de cápsula fibrosa circunjacente ao implante, e neoformação óssea. Segundo as condições experimentais, concluímos que o polímero poliuretano da mâmona, implantado em leito subperióstico, não desencadeou reação inflamatória tardia significativa, tendo levado ao desenvolvimento de cápsula fibrosa circunscrita, com evolução para neoformação óssea. Sinais de rejeição, exposição ou expulsâo do implante não foram observados

Decision criteria for optimizing postemergence Johnsongrass control in soybean crops in Argentina

Foram conduzidos experimentos de campo durante quatro anos agrícolas em Zavalla e Oliveros, Argentina, com o objetivo de otimizar o controle químico de capim-massambará (Sorghum halepense (L.) Pers.), usando o modelo do calendário térmico em comparação com outros critérios de decisão (altura da planta daninha ou dias após a semeadura). O efeito do herbicida foi determinado por avaliação visual, densidade de perfilhos originados de rebrota de rizomas e de touceira e caule, e rendimento de grão de soja. As aplicações segundo o critério do calendário térmico mostraram o melhor controle. A altura da planta daninha na primeira época evidenciou pouca variabilidade entre tratamentos, mas foi muito variável pela segunda e terceira época, atingindo, em alguns casos, valores maiores que 120 cm. Os rendimentos da cultura na primeira e segunda época não diferiram entre si e superaram o rendimento da terceira época. A maior densidade de rebrota de rizomas foi observada na primeira época de aplicação, e o maior rebroto de touceira e caule foi determinado na terceira época. Os parâmetros associados com a eficiência mostraram o melhor comportamento na segunda época. Contudo, a altura da planta nesse momento pode interferir com a aplicação do herbicida e a variabilidade mostrada por esse parâmetro salienta o risco de determinar a época de controle usando só um critério de decisão.Field studies were established in Zavalla and Oliveros, Argentina, during four years in order to optimize Johnsongrass (Sorghum halepense (L.) Pers.) chemical control by means of the thermal calendar model in comparison with other criteria (weed height or days after sowing). The effect of three application dates of postemergence herbicides was determined by visual control, density of tillers originated from rhizome bud regrowth, and from crown and shoot bud regrowth, and soybean yield. Following the thermal calendar model criterion, applications during the second date afforded the best control. Weed height for the first date showed little variability between experiments but was highly variable in the second and third application dates, achieving in some cases values greater than 120 cm. For all years, no significant differences were detected for crop yield between the first and second application dates, and yields were always lower for the third date. The greatest rhizome bud regrowth was observed for the earliest application date and the highest crown and shoot bud regrowth was determined for the last application date. Parameters associated with control efficiency showed the best behaviour for the second date. However, plant height at this moment may interfere with herbicide application and the variability exhibited by this parameter highlights the risk of determining control timing using only one decision criterion

Plasma metalloproteinase activity is enhanced in the euglobulin fraction of breast and lung cancer patients

Matrix metalloproteinases (MMP) have been implicated in tumor invasion and metastasis. We verified, by gelatin zymography, MMP activity in the euglobulin plasma fraction of 82 healthy controls, 66 patients with benign diseases and 149 patients with breast, lung, colon or brain cancer. The euglobulin fractions assayed showed 4 gelatinolytic bands of 62, 92, 120 and 200 kDa. The median (Md) value for 92 kDa-MMP activity was significantly increased in breast (Md 1.34 arbitrary units [AU]/ml plasma, range 0.0–7.2) and lung cancer patients (Md 1.43 AU/ml, range 0.0–3.6) compared with the controls (Md 0.48 AU/ml, range 0.0–1.8). Patients with colon cancer or gliomas presented values of MMP-9 similar to those of the healthy population. Multivariate analysis indicated that plasma MMP-9 activity was not predicted by the known clinicopathological parameters such as age, stage, tumor size, number of positive lymph nodes, histologic grade, histologic type, nuclear grade or mitotic index. Lung cancer patients also presented high values of MMP-9 (Md 1.43, range 0.0–3.6 [n = 26]), without association with tumor stage or histologic type. The levels of 92 kDa-MMP activity in the plasma euglobulin fraction could be a potentially useful tumor marker in breast and lung cancer.Fil: Farias, Eduardo Francisco. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ranuncolo, Stella Maris. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cresta Morgado, Carlos. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; ArgentinaFil: Specterman, Sergio. Hospital Italiano; ArgentinaFil: Armanasco, Eduardo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología ; ArgentinaFil: Varela, Mirta. Hospital Italiano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lastiri, José. Hospital Italiano; ArgentinaFil: Pallotta, María Guadalupe. Hospital Italiano; ArgentinaFil: Bal, Elisa Dora. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Puricelli, Lydia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología; Argentin

Sensitivity of conyza sumatrensis biotypes to glyphosate and ALS-inhibiting herbicides at two growth stages

Conyza sumatrensis es una de las malezas más problemáticas de Argentina, con frecuentes fallas de control después de la aplicación de glifosato. El objetivo del trabajo fue evaluar la sensibilidad de biotipos de C. sumatrensis, en dos estados de desarrollo (roseta y vegetativo), a glifosato y a inhibidores de la enzima acetolactato sintasa (ALS). Se realizaron estudios de dosis-respuesta utilizando 0, 1/16, 1/8, 1/4, 1/2, 1, 2, 4, 8 y 16 veces la dosis recomendada para cada herbicida. Al estado de roseta el nivel de resistencia para glifosato fue de 9,8, mientras que en estado vegetativo ninguno de los biotipos fue controlado con la dosis recomendada, siendo menor la sensibilidad del biotipo R (IR = 2,3). El control de ambos biotipos con inhibidores de la ALS fue excelente al estado de roseta, con dosis menores que las recomendadas. Al estado vegetativo los controles fueron adecuados (80 %) con dosis menores que las recomendadas (0,16 X a 0,97 X), excepto para metsulfuron-metil + clorsulfuron en el biotipo S (1,75 X). Estos resultados confirmarían la existencia de un biotipo resistente a glifosato en Argentina y que los herbicidas inhibidores de la ALS pueden controlar biotipos resistentes e individuos más desarrollados.Conyza sumatrensis is one of the most problematic weeds in Argentina, with frequent control failures after glyphosate application. The objective of this research was to evaluate sensitivity of C. sumatrensis biotypes, at two growth stages (rosette and vegetative), to glyphosate and acetolactate synthase (ALS)-inhibiting herbicides. Dose-response experiments were performed using 0, 1/16, 1/8, 1/4, 1/2, 1, 2, 4, 8, and 16-fold of the recommended dose for each herbicide. At rosette stage, the resistance level for glyphosate was 9.8, while at the vegetative stage neither biotype was controlled with the recommended dose, with lower sensitivity of biotype R (RI = 2.3). Control of both biotypes using ALS-inhibiting herbicides was excellent at rosette stage, with lower doses than the recommended. At vegetative stage controls were good (80 %) with lower doses than recommended (0.16 X to 0.97 X), except for metsulfuron-methyl + chlorsulfuron in biotype S (1.75 X). These results may confirm the existence of a biotype resistant to glyphosate in Argentina and that ALS-inhibiting herbicides could control resistant biotypes and more developed individuals.Fil: Balassone, Federico Emmanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; ArgentinaFil: Puricelli, Eduardo Carlos Jose Maria. Universidad Nacional de Rosario. Facultad de Cs.agrarias. Departamento de Producción Vegetal. Cátedra Terapeutica Vegetal; ArgentinaFil: Faccini, Delma Edith. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentin