RESUMO Objetivo: Avaliar uma nova abordagem fisiológica para a determinação do volume corrente em ventilação mecânica, de acordo com a capacidade inspiratória, e determinar se isso resulta em medidas mecânicas e de troca gasosa adequadas em cães saudáveis e em estado crítico. Métodos: Incluíram-se, neste estudo, 24 animais para avaliar o volume corrente expresso como porcentagem da capacidade inspiratória. Para mensuração da capacidade inspiratória, o ventilador mecânico foi regulado como segue: modo controle de pressão, com 35cmH2O de pressão de inspiração e pressão expiratória final de zero, por 5 segundos. Subsequentemente, estudaram-se dez cães em condições clínicas críticas. Resultados: Cães saudáveis ventilados com volume corrente que correspondia a 17% da capacidade inspiratória demonstraram mecânica respiratória normal e apresentaram os valores previstos de PaCO2 mais frequentemente do que os animais nos demais grupos. A pressão no sistema respiratório e a pressão transpulmonar foram significantemente mais elevadas nos cães em condição crítica, porém em todos os casos, estiveram abaixo de 15cmH2O. Conclusões: O volume corrente calculado com base na capacidade inspiratória de cada animal comprovou ser uma ferramenta útil e simples para o estabelecimento dos parâmetros do ventilador. Convém também realizar abordagem semelhante em outras espécies, inclusive no ser humano, quando se consideram as potenciais limitações da titulação do volume corrente, com base no peso corpóreo ideal calculado.

ABSTRACT Objective: To evaluate a novel physiological approach for setting the tidal volume in mechanical ventilation according to inspiratory capacity, and to determine if it results in an appropriate mechanical and gas exchange measurements in healthy and critically ill dogs. Methods: Twenty healthy animals were included in the study to assess the tidal volume expressed as a percentage of inspiratory capacity. For inspiratory capacity measurement, the mechanical ventilator was set as follows: pressure control mode with 35cmH2O of inspired pressure and zero end-expiratory pressure for 5 seconds. Subsequently, the animals were randomized into four groups and ventilated with a tidal volume corresponding to the different percentages of inspiratory capacity. Subsequently, ten critically ill dogs were studied. Results: Healthy dogs ventilated with a tidal volume of 17% of the inspiratory capacity showed normal respiratory mechanics and presented expected PaCO2 values more frequently than the other groups. The respiratory system and transpulmonary driving pressure were significantly higher among the critically ill dogs but below 15 cmH2O in all cases. Conclusions: The tidal volume based on the inspiratory capacity of each animal has proven to be a useful and simple tool when setting ventilator parameters. A similar approach should also be evaluated in other species, including human beings, if we consider the potential limitations of tidal volume titration based on the calculated ideal body weight.

This is a comparative study about spores carried out in North-West Argentine species of the genus Elaphoglossum: E. crassipes (Hieron.) Diels, E. gayanum (Fée) T. Moore, E. lindbergii (Mett. ex Kuhn) Rosenst.,E. lorentzii (Hieron.) H. Christ, E.piloselloides (C. Presl) T. Moore y E. yungense de la Sota. The spores were studied under light microscope and scanning electron microscope. The spores are monolete and the shape in polar view is elliptic. Mature spores have a sporodermm composed of exospore and perispore. The exospore is always smooth. The macro-ornamentation of perispore can be cristate, muriform (rugate-retate) and stelliform (echinate); granular micro-ornamentation can be seen frequently in perispores. While the aperture is a generic trait, the combination of the micro and macro-ornamentation types of the perispores varies at specific level.

Este es un estudio morfológico comparativo, realizado con MO y MEB, sobre las esporas de E. crassipes (Hieron.) Diels, E. gayanum (Fée) T. Moore, E. lindbergii (Mett. ex Kuhn) Rosenst.,E. lorentzii (Hieron.) H. Christ, E. piloselloides (C. Presl) T. Moore y E. yungense De la Sota, presentes en el noroeste argentino. Las esporas son monoletes y de forma elíptica en vista polar. La esporodermis está constituida por dos paredes: exosporio y perisporio. El exosporio es siempre liso. El perisporio presenta macro-ornamentación crestada, muriforme (rugada-retiada) y esteliforme (equinada), frecuentemente con micro-ornamentación granular. Mientras el tipo de apertura es un rasgo genérico, la combinación de los tipos de micro y macro-ornamentación, resultaron de valor diagnóstico a nivel específico.

La familia Marattiaceae, que incluye de cuatro a seis géneros, presenta estructuras esporógenas de dos tipos: sinangios en Christensenia, Danaea y Marattia; y soros con eusporangios libres en Angiopteris y Archangiopteris. Marattia es un género pantropical con unas ocho-diez especies en el paleotrópico y siete-ocho en el neotrópico. Mediante MEB se estudiaron las esporas de las siete especies neotropicales de Marattia: M. alata, M. cicutifolia, M.excavata, M. interposita, M. laevis, M. laxa y M. weinmanniifolia, basado en la forma de los receptáculos y la posición de los sinangios en material proveniente de distintas colecciones. Los receptáculos son hiperdesarrollados en M. cicutifolia y M. laevis, y apenas sobreelevados en el resto de las especies. Los sinangios son elipsoidales y la posición en la lámina es intramarginal a medial. Las esporas son elípticas, siempre monoletes y no se encuentran esporas triletes, abortadas o deformadas. La lesura tiene una longitud aproximadamente igual a la mitad del diámetro de la espora. El perisporio aparece como una capa delgada continua que se deposita siguiendo los procesos del exosporio, en M. cicutifolia y M. laevis. Es liso en M. alata, rugado en M. excavata y pustulado-rugado en dos especies: M. interposita y M. laxa. El exosporio es equinado en M. cicutifolia y M. laevis, y pustulado en las otras especies. En M. weinmanniifolia, las esporas producidas por el mismo sinangio tienen diferentes tipos de ornamentación. La presencia de sinangios elipsoidales superficiales y de esporas monoletes, son rasgos genéricos; mientras que los tipos de micro-ornamentación y macroornamentación en exosporios y perisporios son caracteres diagnósticos específicos. La macro-ornamentación puede ser buliforme (pustulada), una combinación de buliforme y muriforme (pustulada-rugada), muriforme (rugada-retiada) y esteliforme (equinada); es frecuente la presencia de micro-ornamentación granular en el perisporio.

Spores morphology and synangia in neotropical fern species of Marattia (Marattiaceae). The Marattiaceae are represented by a small family of four to six genera that bear esporogenous structures of two types: sorus with free eusporangia in Angiopteris and Archangiopteris, and indurated synangium in Christensenia, Danaea and Marattia. Marattia is a pantropical genus of about eight to ten species in the paleotropic and seven to eight species in the neotropic. In order to describe the spores and sinangia morphology, this study analyzed the shape of the receptacles, and the position of the synangia, and evaluated the spores with SEM, of seven neotropical species of the genus Marattia: M. alata, M. cicutifolia, M. excavata, M. interposita, M. laevis, M. laxa y M. weinmanniifolia from several collections. The receptacles were fully developed in M. cicutifolia and M. laevis, and scarcely overelevated in the rest of the species. The synangium was ellipsoidal and had intramarginal to supramedial position in the laminae. The spores of Marattia were elliptic. Among the taxa, only monolete spores were found, with no trilete, aborted or deformed spores. The laesura was linear and reached about two of the total length of the spore. The perispore appears as a continuous thin layer deposited on the exospore according to its ornamentation in M. cicutifolia and M. laevis. It is smooth in M. alata, rugate in M. excavata and pustulate-rugate in two species: M. interposita and M. laxa. The exospore is echinate in M. cicutifolia and M. laevis and pustulate in the other species. In M. weinmannifolia spores produced by the same sinangium may have different ornamentation types. We concluded that, while the presence of ellipsoidal and superficial synangia and monolete spores aperture were generic traits, the micro and macro-ornamentation types of the perispores and exospores vary at specific level. Besides, macro-ornamentation can be bulliform (pustulate), a combination of bulliform and muriform types (pustulate-rugate), muriform (rugate-retate) and stelliform (echinate); finally, granular micro-ornamentation can be seen frecuently in perispores. Rev. Biol. Trop. 59 (4): 1833-1844. Epub 2011 December 01.

This is a comparative study about indument and epidermical patterns of laminae carried out in seven argentine species of the genus Elaphoglossum: E. crassipes (Hieron.) Diels, E. gayanum (Fée) T. Moore, E. lindbergii (Mett. ex Kuhn) Rosenst., E. lorentzii (Hieron.) H. Christ, E. pachydermum (Fée) T. Moore, E. piloselloides (C. Presl) T. Moore y E. yungense de la Sota. These characters are diagnostic at the specific level. A key to identify the species was obtained from the results.

Este es un estudio comparativo sobre el indumento y los modelos epidérmicos de las siete especies argentinas del género Elaphoglossum: E. crassipes (Hieron.) Diels, E. gayanum (Fée) T. Moore, E. lindbergii (Mett. ex Kuhn) Rosenst., E. lorentzii (Hieron.) H. Christ, E. pachydermum (Fée) T. Moore, E. piloselloides (C. Presl) T. Moore y E. yungense de la Sota. Estos caracteres resultaron de valor diagnóstico a nivel específico. Los resultados obtenidos se aplican en una clave para la determinación de las especies.

This paper is a taxonomic study of the Argentinean species of the genus Elaphoglossum (E. crassipes, E. gayanum, E. lindbergii, E. lorentzii, E. pachydermum, E. piloselloides and E. yungense), based on morphological characters of the sporophyte. The history of the genus and the description of the species are provided, along with synonymy, comments on geographical distribution, habitat and a list of the studied specimens. A key to identify the species is also given.

Este trabajo es un estudio taxonómico de las especies argentinas del género Elaphoglossum (E. crassipes, E. gayanum, E. lindbergii, E. lorentzii, E. pachydermum, E. piloselloides y E. yungense) basado en caracteres morfológicos del esporófito. Se presenta la historia del género y una descripción de las especies, juntamente con comentarios sobre su distribución geográfica, hábitat, y una lista de los ejemplares estudiados. También se incluye una clave para la determinación de las especies.

Intercellular pectic protuberances (IPP) found in mesophyll cells of neotropical species of Marattia were studied with SEM. The IPP were examinated to determine if they could provide diagnostic characters. Morphologically, three major types are described: pectic warts, filaments and connections (strands). The use of morphological variation with taxonomic character is useful as a complement of other sporophyte traits.

Las protuberancias intercelulares pécticas (PIP) presentes en las células del mesofilo de especies neotropicales de Marattia fueron estudiadas con MEB. Morfológicamente se encontraron 3 tipos principales: verrugas, filamentos y conexiones pécticas. El uso de su variación morfológica con carácter taxonómico resulta de utilidad como complemento de otros rasgos del esporófito.

Sporophyte morphology of Asplenium dareoides was reviewed, and development and morphology of its gamethophytes were studied for the first time from spore culture on mineral agar. Spores germinated 10 days after sown, and cultures reached a low percentage of germination (1 to 5%). Filamentous phase was initiated at 15 days. Gametophytes followed the Aspidium type of development, which leads to a hairy adult state, with cylindrical, marginal and superficial hairs. The morphological study of the sporophyte was based on foliar architecture, indument, epidermal patterns of pinnulae and indusium, spore size (mean values between 28.9 and 39.7 µm) and spore morphology. Gametic chromosome number found was n = 72. Morphological and palynological characters of A. dareoides do not support the close relationship with A. flabellifolium, recently suggested from molecular data.

Se revisó la morfología del esporófito y se estudió por primera vez el desarrollo y la morfología del gametófito de Asplenium dareoides, a partir de esporas cultivadas en un medio nutritivo solidificado con agar. Las esporas germinaron a partir de los 10 días en un porcentaje muy bajo (1 al 5%). La fase filamentosa se inició a los 15 días. Los gametófitos siguieron un modelo de desarrollo de tipo Aspidium, y en la madurez presentaron pelos marginales y superficiales, cilíndricos y algo ensanchados en el ápice. El estudio morfológico del esporófito se basó en la arquitectura foliar, el indumento, el modelo epidérmico de las pínnulas y de los indusios, y en la morfología y el tamaño de las esporas (longitud media de 28,9 a 39,7 µm). El estudio de la meiosis arrojó un número cromosómico gamético n = 72. Los caracteres morfológicos externos y palinológicos de A. dareoides no reflejan su parentesco con A. flabellifolium, recientemente sugerido sobre la base de caracteres moleculares.