Journal articles: 'Xenodon'

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Tozetti, Alexandro Marques, Roberto Baptista de Oliveira, and Glaucia Maria Funk Pontes. "Defensive repertoire of Xenodon dorbignyi (Serpentes, Dipsadidae)." Biota Neotropica 9, no. 3 (September 2009): 157–63. http://dx.doi.org/10.1590/s1676-06032009000300016.

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The ability of a species to defend itself against a predator is directly correlated with its survivorship. Thus, prey/predator interaction mechanisms are important elements of the natural history of species. In this study, we examined the defensive repertoire of the South-American hognose snake (Xenodon dorbignyi) through simulations of predator attacks in the field. Nine defensive displays were observed. The most frequently observed displays were erratic movements, body flattening, head triangulation and tail display. No differences were detected in the defensive strategies shown by males and females, regardless of their reproductive state. Our findings suggest that X. dorbignyi has the ability to evaluate the level of threat imposed by the aggressor, with cryptic behavior, body flattening and locomotor escape as the primary defensive strategies, with other displays used as secondary responses to a predator attack. Our results support the hypothesis that X. dorbignyi is a mimic of both Micrurus and Bothrops.

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Murta-Fonseca, Roberta Azeredo, Alessandra Machado, Ricardo Tadeu Lopes, and Daniel Silva Fernandes. "Sexual dimorphism in Xenodon neuwiedii skull revealed by geometric morphometrics (Serpentes; Dipsadidae)." Amphibia-Reptilia 40, no. 4 (2019): 461–74. http://dx.doi.org/10.1163/15685381-20191147.

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Abstract Sexual dimorphism in snake head/skull is poorly known, although analyses in other vertebrate groups have already pointed this kind of morphological difference. Herein we evaluated the existence of sexual dimorphism in the skull of Xenodon neuwiedii through Geometric Morphometrics (GM). We found that females have larger skulls than males using centroid size data. Considering the ventral view of the palatomaxillary apparatus, compared to females, males tend to have longer maxilla, ectopterygoid slightly laterally shifted, palatine slightly shorter, and longer pterygoid. For the dorsal view, males showed larger snout, more oblique frontoparietal suture, posterior region of the skull more tapered, larger supraoccipital, and larger and more oblique supratemporals. Xenodon neuwiedii showed static allometry only for the symmetric component of the dorsal view, with 9.7% of shape variation explained by size. The present study is the first evaluating and describing sexual dimorphism in skull shape for snakes independently of size. We compared our results with other studies and concluded that to accurately perform intraspecific analyses or to better understand sexual and/or natural selection, sexual dimorphism should be considered, even for structures (e.g. skull) that are traditionally not used for this purpose.

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D'Angelo, Julia Soledad, Federico Lisandro Agnolín, and Florencia Anyelen Godoy. "Xenodon histricus (Jan, 1863) (Squamata: Dipsadidae): distribution extension and new province record in Argentina." Check List 11, no. 5 (September 14, 2015): 1737. http://dx.doi.org/10.15560/11.5.1737.

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Xenodon histricus is probably the least known species of its genus in South America. In Argentina it has not been collected since 1937, and most records were restricted to the northeastern forests of the country. We report finding this species in 1995 at San José del Morro, San Luis province, Central Argentina. This report fills a gap in the distribution of this taxon, and constitutes the most recent record of the species for the country.

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Pinto Lima Gendler, José Luiz, Solange Nogueira de Souza, Otavio Augusto Vuolo Marques, Karina Takesaki Miyaji, and Carlos Roberto de Medeiros. "Bites by Xenodon merremii (Wagler, 1824) and Xenodon neuwiedii (Günther, 1863) (Dipsadidae: Xenodontini) in São Paulo, Brazil: a retrospective observational study of 163 cases." Toxicon 198 (July 2021): 24–31. http://dx.doi.org/10.1016/j.toxicon.2021.04.021.

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Prigioni, Carlos, Claudio Borteiro, and Francisco Kolenc. "Amphibia and Reptilia, Quebrada de los Cuervos, Departamento de Treinta y Tres, Uruguay." Check List 7, no. 6 (December 1, 2011): 763. http://dx.doi.org/10.15560/11021.

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We present an annotated list of the herpetofauna at the Protected Area Quebrada de los Cuervos, Departamento de Treinta y Tres, Uruguay. We recorded 24 species of amphibians and 29 of reptiles, accounting for near half of the species already reported from Uruguay. New records of Dendropsophus minutus (Hylidae) and Liophis almadensis (Colubridae) are presented, being the southernmost known for these species. Additionally, Melanophryniscus sanmartini (Bufonidae), Anisolepis undulatus (Polychridae), Crotalus durissus terrificus (Viperidae) and Xenodon histricus (Colubridae) are cited for the first time for the Departamento de Treinta y Tres.

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Marques Barcellos, José Fernando, Erika Branco, and Daylla Pontes. "Aspectos morfométricos do tubo digestório de Roeboides xenodon e Orthospinus franciscensis." Biotemas 27, no. 3 (June 6, 2014): 139. http://dx.doi.org/10.5007/2175-7925.2014v27n3p139.

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Boulenger, E. G. "7. On a Colubrid Snake (Xenodon) with a vertically movable Maxillary Bone." Proceedings of the Zoological Society of London 85, no. 1 (July 7, 2010): 83–85. http://dx.doi.org/10.1111/j.1469-7998.1915.00083.x.

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MATIAS, CICERA SILVILENE LEITE, DRAUSIO HONORIO MORAIS, and ROBSON WALDEMAR ÁVILA. "Physaloptera nordestina n. sp. (Nematoda: Physalopteridae) parasitizing snakes from Northeastern Brazil." Zootaxa 4766, no. 1 (April 17, 2020): 173–80. http://dx.doi.org/10.11646/zootaxa.4766.1.9.

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Physaloptera nordestina n. sp. (Nematoda: Physalopteridae) is described from the stomach of the snakes Oxybelis aeneus (Wagler), Pseudoboa nigra (Duméril, Bibron & Duméril) and Xenodon merremii (Wagler) (Squamata: Snakes), collected in northeastern Brazil. The new species has males with ornamented caudal alae connected ventrally, anterior to the cloaca, 21 caudal papillae, including four pedunculated and 13 sessile pairs (six surrounding the cloaca and three at tail), spicules sub-equal in size and with different shape. In addition, the females have the vulva located on the anterior third of the body and two to four uterine branches. Here we present the ninth species of Physaloptera that parasitizes reptiles from Brazil.

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FERREIRA-SILVA, CRISTIANA, EDNA P. ALCANTARA, ROBSON W. ÁVILA, and REINALDO J. SILVA. "A new species of Hastospiculum Skrjabin (Spirurida: Diplotriaenidae) parasite of Xenodon merremii (Walger in Spix) (Serpentes: Dipsadidae) from Northeastern Brazil." Zootaxa 4878, no. 2 (November 13, 2020): 362–74. http://dx.doi.org/10.11646/zootaxa.4878.2.9.

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A new nematode species of the Diplotriaenidae is described from the Neotropical region. The species was found infecting the body cavity of the snake Xenodon merremii (Wagler in Spix) collected in the municipality of Barbalha, Ceará State, Northeastern Brazil. Hastospiculum nordestinum n. sp. differs from the congeners by combining the following characters: caudal end ornamented with lateral alae not surrounding the tail end and not connected, supported by eight pairs of pedunculated papillae (three precloacal, one paracloacal, and four postcloacal pairs) and three adcloacal sessile papillae, and left spicule length 719.6–902.4 µm. Besides the description of Hastospiculum nordestinum n. sp., a species list and a dichotomous key to Hastospiculum are provided.

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CURCIO, FELIPE F., VÍTOR DE Q. PIACENTINI, and DANIEL S. FERNANDES. "On the status of the snake genera Erythrolamprus Boie, Liophis Wagler and Lygophis Fitzinger (Serpentes, Xenodontinae)." Zootaxa 2173, no. 1 (July 31, 2009): 66–68. http://dx.doi.org/10.11646/zootaxa.2173.1.7.

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The genus Erythrolamprus Boie (1826) comprises six species of Central and South American false coral snakes (Peters & Orejas-Miranda 1970; Zaher 1999; Curcio et al. 2009). It is traditionally allocated in the tribe Xenodontini (subfamily Xenodontinae), along with the genera Liophis, Lystrophis, Umbrivaga, Waglerophis and Xenodon (sensu Dixon 1980; Cadle 1984; Myers 1986; Ferrarezzi 1994; Zaher 1999). Although Xenodontini is supported by morphological and molecular evidence, phylogenetic relationships and classification within the tribe have been the subject of recent debate. Molecular phylogenetic studies have recovered clades with Erythrolamprus nested within some representatives of the genus Liophis (Vidal et al. 2000; Zaher et al. 2009), partly corroborating previous hypotheses based on morphology (e.g. Dixon 1980).

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Ozzetti, Priscila Aparecida, Carolina Limonge Cavlac, and Ida Sigueko Sano-Martins. "Hematological reference values of the snakes Oxyrhopus guibei and Xenodon neuwiedii (Serpentes: Dipsadidae)." Comparative Clinical Pathology 24, no. 1 (December 24, 2013): 101–8. http://dx.doi.org/10.1007/s00580-013-1866-6.

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Pinheiro, Leandra C., Pedro S. Abe, Youszef O. C. Bitar, Luiz P. P. Albarelli, and Maria C. Santos-Costa. "Composition and ecological patterns of snake assemblages in an Amazon-Cerrado Transition Zone in Brazil." Iheringia. Série Zoologia 105, no. 2 (June 2015): 147–56. http://dx.doi.org/10.1590/1678-476620151052147156.

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ABSTRACT The present study encompasses the species composition and ecological characteristics of the snake community in a Cerrado-Amazon transition zone in Midwest of Brazil (state of Mato Grosso). The data were collected during six excursions to the "Tanguro" (study area) by visual encounter survey, pitfall traps with drift fences and non-systematic sampling. We collected 194 specimens, distributed in 34 species, 26 genera, and eight families. The most abundant species were Crotalus durissus Linnaeus, 1758 (n = 50), Philodryas olfersii (Lichtenstein, 1823) (n = 15), Philodryas nattereri Steindachner, 1870 (n = 13), Xenodon rabdocephalus (Wied, 1824) (n = 12), Lachesis muta (Linnaeus, 1766) (n = 10) and Erythrolamprus almadensis (Wagler, 1824) (n = 10). The composition of species found here represents a combination of Cerrado and Amazonian savanna fauna.

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Bustos, María Lucía, Matías Nicolás Sánchez, María Elisa Peichoto, and Gladys Pamela Teibler. "Primer registro de enfermedad fúngica en una serpiente sudamericana: características clínicas y patológicas." Revista de Investigaciones Veterinarias del Perú 29, no. 3 (September 6, 2018): 1036. http://dx.doi.org/10.15381/rivep.v29i3.15072.

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La Enfermedad Fúngica de las Serpientes (EFS) ha sido reportada en varias especies de serpientes cascabel y de colúbridos de Estados Unidos de América y Europa, pero no en América del Sur. Un espécimen del colúbrido sudamericano Xenodon merremii (conocido popularmente como falsa yarará) arribó al Servicio de Emergencia del Hospital de Clínicas de la Facultad de Ciencias Veterinarias de la Universidad Nacional del Nordeste (Argentina), presentando una solución de continuidad costrosa en la piel, y otra lesión consistente en decoloración y pérdida de brillo de las escamas. El ejemplar falleció a los 16 días de iniciado el tratamiento. A la necropsia, se observaron lesiones en el parénquima hepático, mientras que el pulmón no evidenció lesiones macroscópicas apreciables. Las lesiones encontradas fueron compatibles con EFS.

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Eterovic, André, Otavio Marques, and Whaldener Endo. "Seasonal activity of snakes in the Atlantic forest in southeastern Brazil." Amphibia-Reptilia 22, no. 1 (2001): 103–11. http://dx.doi.org/10.1163/156853801750096213.

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AbstractSeasonal abundance of some snake species from the Atlantic forest in southeastern Brazil was inferred from collection data gathered throughout twelve years at the Instituto Butantan in São Paulo, Brazil. The number of collected individuals of Chironius spp., Liophis miliaris, Spilotes pullatus, Tropidodryas spp., Micrurus corallinus, and Bothrops jararaca was significantly higher during the rainy season, whereas the number of Sibynomorphus neuwiedi was higher during the dry season. Erythrolamprus aesculapii, Xenodon neuwiedii, Tomodon dorsatus and Bothrops jararacussu did not show significant differences in the number of individuals collected at each of these seasons. Seasonality in captures may result from seasonal activity patterns. Food availability, tolerance to climatic conditions, reproductive cycle, and phylogenetic constraints are considered the main factors responsible for the observed patterns. A multivariate approach is recommended for analysis of annual activity.

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Lucena, Carlos Alberto Santos de. "Revisão taxonômica das espécies do gênero Roeboides grupo-affinis (Ostariophysi, Characiformes, Characidae)." Iheringia. Série Zoologia 97, no. 2 (June 30, 2007): 117–36. http://dx.doi.org/10.1590/s0073-47212007000200001.

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A revisão taxonômica do gênero Roeboides grupo-affinis é apresentada. Sete espécies são reconhecidas: R. affinis (Günther, 1868) das drenagens dos rios Amazonas, Orinoco e Paraná-Paraguai, rios da Guiana, Suriname e sistema Tocantins-Araguaia; R. biserialis Garman, 1890 da drenagem do rio Amazonas; R. descalvadensis Fowler, 1932 das drenagens dos rios Amazonas e Paraná-Paraguai; R. oligistos Lucena, 2000 da bacia do rio Amazonas; R. numerosus Lucena, 2000 da bacia do rio Orinoco; R. xenodon (Reinhardt, 1851) da bacia do rio São Francisco e R. sazimai sp. nov., conhecida dos rios Parnaíba and Pindaré-Mearim, nordeste do Brasil. Roeboides paranensis Pignalberi, 1975 é considerado sinônimo de R. descalvadensis; Roeboides prognathus e R. thurni Eigenmann, 1912 sinônimos de R. affinis. Lectótipos são designados para R. affinis, R. biserialis e R. francisci Steindachner, 1908. Uma chave de identificação das espécies de Roeboides grupo-affinis é fornecida.

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Falcione, Camila, Alejandra Hernando, Diego Andrés Barrasso, and Diego Omar Di Pietro. "Karyotypes of four species of Xenodontini snakes (Serpentes) and implications for taxonomy." Contributions to Zoology 85, no. 3 (July 28, 2016): 265–73. http://dx.doi.org/10.1163/18759866-08503001.

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The karyotypes of four Xenodontini snake species, Lygophis dilepis, L. meridionalis, L. flavifrenatus and L. anomalus, are here described for the first time. We studied specimens from northeastern Argentina using conventional and silver (Ag-NOR) staining. While the typical ophidian karyotype is 2n = 36, we found that the karyotype of the studied species is 2n = 34, with metacentric and submetacentric chromosome pairs. The 4th NOR staining revealed that nucleolar organizer regions (NORs) are located on one pair of microchromosomes. In L. dilepis and L. anomalus the 4th chromosome pair is heteromorphic, and we suggest that it might be considered as the ZW sex chromosome pair. The optimization of available karyological data on a molecular phylogenetic tree of the tribe Xenodontini shows that the diploid numbers 2n = 28, 30 and 34 represent putative synapomorphy for Erythrolamprus, Xenodon and Lygophis, respectively. Our results provide new insights which fill gaps in our knowledge on the cytology in the genus Lygophis and identified a possible diagnostic character for the genus.

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Pizzatto, LÍgia, Rosana S. Jordão, and Otavio A. V. Marques. "Overview of Reproductive Strategies in Xenodontini (Serpentes: Colubridae: Xenodontinae) with New Data for Xenodon Neuwiedii and Waglerophis Merremii." Journal of Herpetology 42, no. 1 (March 2008): 153–62. http://dx.doi.org/10.1670/06-150r2.1.

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Bernarde, Paulo Sérgio, Saymon de Albuquerque, Thiago Oliveira Barros, and Luiz Carlos Batista Turci. "Serpentes do Estado de Rondônia, Brasil." Biota Neotropica 12, no. 3 (September 2012): 154–82. http://dx.doi.org/10.1590/s1676-06032012000300018.

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Esse estudo teve como objetivo atualizar a lista de serpentes do estado de Rondônia a partir de levantamento bibliográfico, e fornecer algumas informações sobre a distribuição das espécies. São registradas para o estado de Rondônia 118 espécies de serpentes, pertencentes a oito famílias: Leptotyphlopidae (4 espécies), Typhlopidae (1), Aniliidae (1), Boidae (6), Colubridae (21), Dipsadidae (67), Elapidae (9) e Viperidae (9). Dessas, 109 foram registradas para áreas de floresta amazônica e 27 em cerrado. A menor riqueza encontrada em cerrado (27 espécies) provavelmente deve estar associada aos poucos trabalhos desenvolvidos nessas áreas e pelo fato dessa formação vegetal ocupar uma área de cerca de apenas 5% do estado. Nove espécies (Epicrates crassus, Chironius flavolineatus, Drymoluber brazili, Apostolepis striata, Oxyrhopus rhombifer, Pseudoboa nigra, Xenodon merremii, Bothrops mattogrossensis e Crotalus durissus) foram registradas exclusivamente em áreas de cerrado, sendo formas associadas a esse ambiente na Amazônia. Seis espécies (Masticophis mentovarius, Apostolepis striata, Erythrolamprus mimus, Micrurus mipartitus, Micrurus sp. e Bothrocophias microphthalmus) são conhecidas no Brasil apenas para Rondônia. Existem lacunas sobre o conhecimento das serpentes em algumas regiões de Rondônia, sendo essencial a realização de mais estudos de inventário. Tal necessidade se torna mais urgente devido à crescente destruição dos habitats ao longo do Cerrado e nas porções sul da Amazônia.

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Hartmann, Paulo Afonso, Marília Teresinha Hartmann, and Marcio Martins. "Ecologia e história natural de uma taxocenose de serpentes no Núcleo Santa Virgínia do Parque Estadual da Serra do Mar, no sudeste do Brasil." Biota Neotropica 9, no. 3 (September 2009): 173–84. http://dx.doi.org/10.1590/s1676-06032009000300018.

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O objetivo deste estudo foi obter informações sobre a história natural e a ecologia de uma taxocenose de serpentes na Mata Atlântica do alto da Serra do Mar, no Núcleo Santa Virgínia do Parque Estadual da Serra do Mar, nordeste do Estado de São Paulo, Brasil. Os principais aspectos estudados foram riqueza, abundância relativa, padrões de atividade diária e sazonal, utilização do ambiente e dieta. Também são fornecidas informações adicionais sobre outros aspectos da história natural das espécies. Um total de 148 indivíduos, de 27 espécies, 19 gêneros e quatro famílias foi encontrado dentro dos limites do Núcleo Santa Virgínia. As espécies mais frequentemente encontradas foram Bothrops jararaca, Xenodon neuwiedii e Liophis atraventer. A maior parte das espécies é predominantemente diurna e terrícola. Dentre os fatores abióticos analisados para a área de estudo, o mais relacionado à abundância das serpentes foi a temperatura mínima, seguido da temperatura média e da pluviosidade. A maioria das espécies encontradas apresenta dieta concentrada em uma categoria de presa ou restrita a poucos tipos de itens alimentares. Aparentemente, anfíbios anuros são o principal recurso alimentar para as taxocenoses de serpentes da Mata Atlântica do alto da Serra do Mar. Os nossos resultados indicam que a estrutura da taxocenose de serpentes do Núcleo Santa Virgínia reflete principalmente as características ecológicas da linhagem mais representada na taxocenose.

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Foesten, Marilia Hendler, Alexandro Marques Tozetti, and Jairo Afonso Henkes. "AVALIAÇÃO DO NÍVEL DE CONHECIMENTO DA OFIDIOFAUNA POR MORADORES RURAIS DO VALE DO RIO DOS SINOS, SUL DO BRASIL." Revista Gestão & Sustentabilidade Ambiental 5, no. 2 (November 16, 2016): 175. http://dx.doi.org/10.19177/rgsa.v5e22016175-199.

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Este estudo avaliou o nível de conhecimento de uma população rural sobre a fauna de serpentes no sul do Brasil. Foram aplicados questionários à comunidade rural do município de Novo Hamburgo, totalizando 50 entrevistados, durante os meses de julho e setembro do ano de 2012. Durante a pesquisa foram testados conhecimentos dos moradores sobre as diferentes espécies de serpentes que ocorrem nos locais, e suas características biológicas bem como a habilidade desses moradores em reconhecê-las. Dentreos entrevistados a maioria possui forte ligação com o meio rural, baixa escolaridade e conhecimento deficiente sobre a fauna de serpentes. Apesar da alta riqueza de espécies de serpentes que ocorrem na região, cada morador soube citar em menos do que quatro espécies. Além disso, as mais citadas foram às peçonhentas (como a coral verdadeira, Micrurus sp, e a jararaca, Bothrops sp.), as espécies mais abundantes ou mais facilmente observáveis como a cobra-cipó (Philodryas olfersii). Além disso, a maioria dos entrevistados acredita que a ação correta ao encontrar uma serpente no campo é matá-la. Algumas serpentes não peçonhentas foram confundidas com peçonhentas como, por exemplo, Sybnomorphus ventrimaculatus e Philodryas patagoniensis, Xenodon merremi. Desse modo, os dados revelam que a população rural não possui uma boa compreensão sobre a diversidade importância dada serpentes sendo necessárias ações de educação ambiental a respeito da importância em se preservar esses animais.

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Emmerich, Enzo, Drausio Honorio Morais, and Reinaldo José da Silva. "High Infection Level of a Snake, Xenodon merremii (Wagler in Spix, 1824) (Serpentes: Dipsadidae), with Serpentirhabdias cf. vellardi (Pereira, 1928) (Nematoda: Rhabdiasidae) in Brazil." Comparative Parasitology 85, no. 2 (July 2018): 197–201. http://dx.doi.org/10.1654/1525-2647-85.2.197.

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Cornejo Donayre, Alberto. "Investigaciones sobre Patología Tropical en el departamento de Madre de Dios." Anales de la Facultad de Medicina 43, no. 2 (April 9, 2014): 409. http://dx.doi.org/10.15381/anales.v43i2.6300.

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Durante el desarrollo de un programa de investigación sobre patología tropical ene l departamento de Madre de Dios, hubo ocasión para recolectar nueve serpientes en este lugar y dos en la ciudad de Quincemil, zona selvática del departamento del Cuzco, colindante con el de Madre de Dios. Los especímenes fueron estudiados por el Dr. Jehan Vellard, del Museo de Historia Natural Javier Prado de la Universidad Nacional Mayor de San Marcos, quien tuvo la gentileza de informarnos del resultado de sus determinaciones. En esta pequeña colección se consigna especies de la familia Crotalidae, Elapidae y Colubridae, entre las cuales hay especímenes del grupo solenoglipha, proteroglipha, opistoglipha y aglipha. Se señala la presencia de las siguientes especies en el sur-oriente: Bothrops castelnaudi (D.& B.), Lachesis muta (L.), Micrurus peruvianus, Micrurus hemprichii Jan, Xenodon severus (L.), Imantodes cenchoa (L.), Philodryas olfersii Lichtenstein, Oxybelis acuminatus Wied, Dipsa catesbyi Sentzen, Oxyrhopus sp. y un ejemplar de la sub-familia Rhadinea. El Bithrops castelnaudi (D.& B.), es encontrado por primera vez en el Perú y con la Lachesis muta (L.), son las serpientes más peligrosas en esa zona y, posiblemente, responsables de la casi totalidad de accidentes herpéticos. Se comprueba que el departamento de Madre de Dios está incluído en el área de dispersión de la Lachesis muta (L.), en el Perú. Las víboras de coral son comunes en esta parte de la selva y las especies Micrurus peruvianus y Micrurus hemprichii Jan no habían sido encontradas anteriormente en Madre de Dios. Se demuestra la presencia en el sur-oriente, de varias especies de la familia Colubridae que no son peligrosas para el hombre y son comunes en la vecina república del Brasil.

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Cicchi, Paulo José Pyles, Marco Aurélio de Sena, Denise Maria Peccinini-Seale, and Marcelo Ribeiro Duarte. "Snakes from coastal islands of State of São Paulo, Southeastern Brazil." Biota Neotropica 7, no. 2 (2007): 227–40. http://dx.doi.org/10.1590/s1676-06032007000200026.

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There are relatively few studies on snake fauna from coastal islands of the State of São Paulo (SSP), Southeastern Brazil and the number of species housed in Brazilian institutional zoological collections is relatively limited. In Brazil, for the first time, a snake inventory for eighteen islands of coastal SSP is presented. Here we record data from sampling on eleven islands as well information on vouchered species in the main herpetological collections. Thirty-six species from four families: one Boidae, thirty Colubridae, one Elapidae and four Viperidae from eighteen islands are listed as well as the thirteen new island records for snakes. Relative abundance categories were used for species rarity: common, infrequent and rare; 44.4% of the snakes with voucher specimens were considered rare. The most common species in twelve of the eighteen islands was Micrurus corallinus; in eleven of the eighteen islands were Bothrops jararaca and Liophis miliaris; in ten of the eighteen islands were B. jararacussu and Chironius bicarinatus. The most common snake species on coastal islands were Micrurus corallinus which was found in twelve of the eighteen islands, followed by Bothrops jararaca and Liophis miliaris found on eleven of the eighteen islands and B. jararacussu and Chironius bicarinatus which were found in ten of the eighteen islands studied. There are seven new records of snake species for Cardoso Island (25° 05’ S and 047° 59’ W): C. bicarinatus, C. multiventris, Dipsas petersi, Echinanthera bilineata, E. cephalostriata, Helicops carinicaudus and Xenodon neuwiedii; three new records for Comprida Island (24° 54’ S and 47° 48’ W): B. jararacussu, C. bicarinatus and H. carinicaudus; one for Anchieta Island (23° 32’ S and 045° 03’ W): Spilotes pullatus; one for Couves Island (23° 25’ S and 44° 52’ W): L. miliaris; one for Porcos Island (23° 23’ S and 44° 54’ W), B. jararaca. The endemic species B. alcatraz from Alcatrazes Island and B. insularis from Queimada Grande Island are considered endangered species by IUCN. Snake fauna on Monte de Trigo Island are extinct. The fragility of insular snake fauna needs more attention for environmental conservation, since 52.0% of snake species preys on amphibians, highlighting the importance of forest conservation.

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Mann, Shakila. "Art of Xenofon Kavvadias." Feminist Dissent, no. 4 (March 11, 2019): 274–78. http://dx.doi.org/10.31273/fd.n4.2019.413.

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Kavvadias, Xenofon. "Art of Xenofon Kavvadias." Feminist Dissent, no. 4 (March 12, 2019): 305–14. http://dx.doi.org/10.31273/fd.n4.2019.416.

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Singh, Jitendra, and Nirupama Banerjee. "Transcriptional Analysis and Functional Characterization of a Gene Pair Encoding Iron-Regulated Xenocin and Immunity Proteins of Xenorhabdus nematophila." Journal of Bacteriology 190, no. 11 (March 28, 2008): 3877–85. http://dx.doi.org/10.1128/jb.00209-08.

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ABSTRACT We describe a two-gene cluster encoding a bacteriocin, xenocin, and the cognate immunity protein in the insect-pathogenic bacterium Xenorhabdus nematophila, which infects and kills larval stages of the common crop pest Helicoverpa armigera. The two genes, xcinA and ximB, are present in the genome as a single transcriptional unit, which is regulated under SOS conditions. The stress-inducible promoter was activated by mitomycin C, glucose, and Fe3+ depletion and at an elevated temperature when it was tested in Escherichia coli cells. Expression of the xenocin protein alone in E. coli inhibited the growth of this organism. The growth inhibition was abolished when the immunity protein was also present. A recombinant xenocin-immunity protein complex inhibited the growth of E. coli indicator cells when it was added exogenously to a growing culture. Xenocin is an endoribonuclease with an enzymatically active C-terminal domain. Six resident bacterial species (i.e., Bacillus, Enterobacter, Enterococcus, Citrobacter, Serratia, and Stenotrophomonas species) from the H. armigera gut exhibited sensitivity to recombinant xenocin when the organisms were grown under iron-depleted conditions and at a high temperature. Xenocin also inhibited the growth of two Xenorhabdus isolates. This study demonstrates that Fe3+ depletion acts as a common cue for synthesis of xenocin by X. nematophila and sensitization of the target strains to the bacteriocin.

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Tuplin, C. J. "XENOPHON." Classical Review 48, no. 2 (October 1998): 286–88. http://dx.doi.org/10.1017/s0009840x98370018.

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Seidel, S. "Xenon as a Complex Ligand: The Tetra Xenono Gold(II) Cation in AuXe42+(Sb2F11-)2." Science 290, no. 5489 (October 6, 2000): 117–18. http://dx.doi.org/10.1126/science.290.5489.117.

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López Férez, Juan Antonio. "Recepción de Heródoto, Ctesias y Jenofonte en Galeno." FORTUNATAE. Revista Canaria de Filología, Cultura y Humanidades Clásicas 28 (July 2018): 159–74. http://dx.doi.org/10.25145/j.fortunat.2018.28.014.

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Rood, Tim. "Cato the Elder, Livy, and Xenophon’s Anabasis." Mnemosyne 71, no. 5 (September 13, 2018): 823–49. http://dx.doi.org/10.1163/1568525x-12342352.

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AbstractThis article argues firstly that Cato the Elder’s account of a daring plan involving the tribune Caedicius in the First Punic War is modelled on a scene in Xenophon’s Anabasis. It then argues that Livy’s account of a heroic escape in the First Samnite War orchestrated by P. Decius Mus is modelled not just on the First Punic War episode described by Cato, as scholars have suggested, but on the same passage of Xenophon; it also proposes that Livy’s use of Xenophon may be mediated through Cato. The article then sets out other evidence for the use of Xenophon in Roman historiography and explores the implications of the proposed intertextuality for Roman self-positioning and for ideas of leadership and military hierarchy. The article as a whole suggests that the influence of Xenophon on Latin historiography is greater than has often been conceived.

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Nadon, Christopher. "Leo Strauss's First Brush with Xenophon: “The Spirit of Sparta or the Taste of Xenophon”." Review of Politics 83, no. 1 (December 7, 2020): 69–90. http://dx.doi.org/10.1017/s0034670520000728.

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AbstractLeo Strauss is most well known for his thesis on the philosophic practice of exotericism. One of strangest aspects of his work is the amount of attention he devoted to Xenophon. This article attempts to explain how these two important facets of Strauss's thought are connected by examining their connection in his first published treatment of them both: “The Spirit of Sparta or the Taste of Xenophon.”

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O'Connor, Stephen. "THE AGORANOMOI AT COTYORA (XEN. AN. 5.7.21–9): CERASUNTIANS OR CYREANS?" Classical Quarterly 66, no. 1 (April 5, 2016): 84–99. http://dx.doi.org/10.1017/s0009838816000082.

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In the late spring of 400 b.c.e., when the Ten Thousand were encamped outside the city of Cotyora, Xenophon addressed the soldiers gathered in assembly in order to defend himself against accusations that he was planning to lead them on a colonizing expedition to the land of the Phasis river. Having demonstrated that he was not misleading the soldiers (that is, that his true intentions were not to lead them to the Phasis) by proving that he could not hope to deceive them into travelling east, Xenophon then moved on to what he presented as a more serious matter for the assembled mercenaries: the problem of growing indiscipline in the army, and its consequences (both potential and actual). Xenophon illustrated the extent of the problem by describing to the men two incidents in detail.

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Whitehead, Ian. "The Periplous." Greece and Rome 34, no. 2 (October 1987): 178–85. http://dx.doi.org/10.1017/s0017383500028126.

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The naval tactic, the periplous, referred to by both Thucydides and Xenophon has yet to be convincingly identified by any scholar. πɛρπλους and πɛριπλω are widely used in their non-tactical sense to mean ‘a voyage round a stretch of coast’, and ‘to sail round’. The only passages in which we can be certain that Thucydides and Xenophon are writing about the naval tactic are not accounts of battles but passages setting the scene for naval battles, theorizing about sea warfare. The problem then is to separate and identify the tactical from the normal usage. If we study the nature of the theoretical periplous referred to by Thucydides and Xenophon, and then look for a battle manoeuvre of a similar nature, we may be able to make that distinction.

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Shu-jiang, Liu, Chen Zhan-ying, Chang Yin-zhong, Wang Shi-lian, Li Qi, Fan Yuan-qing, Jia Huai-mao, Zhang Xin-jun, and Zhao Yun-gang. "The breakthrough curve combination for xenon sampling dynamics in a carbon molecular sieve column." Analyst 140, no. 2 (2015): 428–33. http://dx.doi.org/10.1039/c4an01766h.

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Somvanshi, Mukesh, Archana Tripathi, Anupama Gupta, and Firoz Satpathy. "Xenon: The Future Anaesthetic Agent." Indian Journal of Anesthesia and Analgesia 5, no. 3 (2018): 493–99. http://dx.doi.org/10.21088/ijaa.2349.8471.5318.23.

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Lockwood, Geoffrey G., Nicholas P. Franks, Neil A. Downie, Kenneth M. Taylor, and Mervyn Maze. "Feasibility and Safety of Delivering Xenon to Patients Undergoing Coronary Artery Bypass Graft Surgery While on Cardiopulmonary Bypass." Anesthesiology 104, no. 3 (March 1, 2006): 458–65. http://dx.doi.org/10.1097/00000542-200603000-00012.

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Background Postoperative neurocognitive deficit is prevalent after cardiac surgery. Xenon may prevent or ameliorate acute neuronal injury, but it also may aggravate injury during cardiac surgery by increasing bubble embolism. Before embarking on a randomized clinical trial to test the safety and efficacy of xenon for postoperative neurocognitive deficit, we undertook a phase I study to investigate the safety of administering xenon to patients undergoing coronary artery bypass grafting while on cardiopulmonary bypass and to assess the practicability of our xenon delivery system. Methods Sixteen patients scheduled for coronary artery bypass grafting surgery with hypothermic cardiopulmonary bypass gave their informed consent to participate in an open-label dose-escalation study (0, 20, 35, 50% xenon in oxygen and air). Xenon was delivered throughout surgery using both a standard anesthetic breathing circuit and the oxygenator. Gaseous and blood xenon partial pressures were measured five times before, during, and after cardiopulmonary bypass. Middle cerebral artery Doppler was used to assess embolic load, and major organ system function was assessed before and after surgery. Results Middle cerebral artery Doppler showed no evidence of increased emboli with xenon. Patients receiving xenon had no major organ dysfunction: Troponin I and S100beta levels tended to be lower in patients receiving xenon. Up to 25 l xenon was used per patient. Xenon partial pressure in the blood tracked the delivered concentration throughout. Conclusions Xenon was safely and efficiently delivered to coronary artery bypass grafting patients while on cardiopulmonary bypass. Prevention of nervous system injury by xenon should be tested in a large placebo-controlled, randomized clinical trial.

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Głogowski, Piotr. "Źródła Diodora do dziejów wyprawy dziesięciu tysięcy." Roczniki Humanistyczne 67, no. 3 (July 8, 2019): 23. http://dx.doi.org/10.18290/rh.2019.67.3-2.

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The Anabasis of Xenophon was not the only account of the expedition of Cyrus. However, the other accounts were lost, and they are known today only thanks to the intermediate tradition. As it is thought, the narrative of Diodorus on the expedition of Cyrus (14, 19-31; 14, 37, 1-4) is based on the lost work of Ephorus of Cyme. It is necessary to state that this account differs to some extent from the narrative of Xenophon. Therefore, the question is what the sources exploited by Ephorus are. The aim of the current work is to present the selection of the most significant differences and similarities between the extent accounts. Furthermore, the most important views concerning this issue are discussed. The evidence which could suggest that the Anabasis is not a source of Ephorus is rather of secondary importance and in many cases could be interpreted otherwise. Despite the linguistic differences between the Anabasis and the Bibliothece, we can notice that in Diodorus there are expressions which resemble greatly these of Xenophon. By considering the similarities between these two narratives, we can assume that the main sources which could be identified in the story of Ephorus and Diodorus are the account of Xenophon supplemented by the information taken from the work of Ctesias.

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Németh, György. "Xenophon der Lügner." Acta Antiqua Academiae Scientiarum Hungaricae 43, no. 3-4 (December 2003): 317–22. http://dx.doi.org/10.1556/aant.43.2003.3-4.5.

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Chaves, John F. "Theodore Xenophon Barber." American Journal of Clinical Hypnosis 48, no. 4 (April 2006): 247–49. http://dx.doi.org/10.1080/00029157.2006.10401531.

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Farrell, Christopher A. "Xenophon Poroi 5." Polis, The Journal for Ancient Greek Political Thought 33, no. 2 (September 20, 2016): 331–55. http://dx.doi.org/10.1163/20512996-12340097.

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The present study examines section five of Poroi and Xenophon’s proposal to restore the reputation of Athens. After outlining his plan for ‘justly’ supplying the dēmos with sufficient sustenance in Poroi 1-4, section 5 addresses the desire to regain hegemony after Athens had lost the Social War. Xenophon does not adopt an anti-imperialist stance; instead he seeks to re-align imperial aspirations with Athenian ideals and earlier paradigms for securing hegemony. Xenophon’s ideas in Poroi are contextualized with consideration for his ‘Socratic’ distinction between tyranny and kingship, as well as his wider advice for ruling well. It is shown that his proposals for securing the consent of the allies reiterates ideas that Xenophon outlines across his corpus, especially Hiero and Cyropaedia. In Poroi Xenophon therefore applies his political thought in an attempt to re-direct Athenian ambitions away from policies that prompted charges of being a ‘tyrant polis’ and towards ‘legitimate rule’.

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Moles, J. L. "Xenophon and Callicratidas." Journal of Hellenic Studies 114 (November 1994): 70–84. http://dx.doi.org/10.2307/632734.

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Despite increasingly sophisticated theoretical debate, scholars concerned with ancient historiography effectively still divide into two camps: historians, who want to use the texts as sources and assess them by criteria of accuracy, reliability, completeness of record and presence or absence of prejudice according to their presumed relationship to the facts which they purport to represent; and literary scholars, who want to interpret the texts as texts, with their own internal logic.

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Huitink, Luuk, and Tim Rood. "Xenophon de Halbattiker?" Lampas 53, no. 4 (January 1, 2020): 420–36. http://dx.doi.org/10.5117/lam2020.4.003.hutt.

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Summary This article analyses Xenophon’s lexical choices in Anabasis. It examines ancient and modern critical approaches to his language: Xenophon has often been criticized for lapses from ‘pure’ Attic, but this notion of a ‘pure’ Attic should be regarded as a conservative response to the increasing variety of spoken Attic in the fourth century BC. Xenophon’s lexical choices reflect the influence both of this ‘Great Attic’ (which developed into koine Greek) and of the non-parochial historiographical tradition inaugurated by Thucydides.

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Frietsch, Thomas, Ralph Bogdanski, Manfred Blobner, Christian Werner, Wolfgang Kuschinsky, and Klaus F. Waschke. "Effects of Xenon on Cerebral Blood Flow and Cerebral Glucose Utilization in Rats." Anesthesiology 94, no. 2 (February 1, 2001): 290–97. http://dx.doi.org/10.1097/00000542-200102000-00019.

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Background The effects of xenon inhalation on mean and local cerebral blood flow (CBF) and mean and local cerebral glucose utilization (CGU) were investigated using iodo-[14C]antipyrine and [14C]deoxyglucose autoradiography. Methods Rats were randomly assigned to the following groups: conscious controls (n = 12); 30% (n = 12) or 70% xenon (n = 12) for 45 min for the measurement of local CBF and CGU; or 70% xenon for 2 min (n = 6) or 5 min (n = 6) for the measurement of local CBF only. Results Compared with conscious controls, steady state inhalation of 30 or 70% xenon did not result in changes of either local or mean CBF. However, mean CBF increased by 48 and 37% after 2 and 5 min of 70% xenon short inhalation, which was entirely caused by an increased local CBF in cortical brain regions. Mean CGU determined during steady state 30 or 70% xenon inhalation remained unchanged, although local CGU decreased in 7 (30% xenon) and 18 (70% xenon) of the 40 examined brain regions. The correlation between CBF and CGU in 40 local brain structures was maintained during steady state inhalation of both 30 and 70% xenon inhalation, although at an increased slope at 70% xenon. Conclusion Effects of 70% xenon inhalation on CBF in rats are time-dependent. During steady state xenon inhalation (45 min), mean values of CBF and CGU do not differ from control values, and the relation of regional CBF to CGU is maintained, although reset at a higher level.

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Schaefer, Wolfgang, Philipp T. Meyer, Rolf Rossaint, Jan H. Baumert, Mark Coburn, Michael Fries, and Steffen Rex. "Myocardial Blood Flow during General Anesthesia with Xenon in Humans." Anesthesiology 114, no. 6 (June 1, 2011): 1373–79. http://dx.doi.org/10.1097/aln.0b013e3182137d9c.

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Background Xenon has only minimal hemodynamic side effects and induces pharmacologic preconditioning. Thus, the use of xenon could be an interesting option in patients at risk for perioperative myocardial ischemia. However, little is known about the effects of xenon anesthesia on myocardial blood flow (MBF) and coronary vascular resistance in humans. Methods Myocardial blood flow was noninvasively quantified by H₂¹⁵O positron emission tomography in six healthy volunteers (age: 38 ± 8 yr). MBF was measured at baseline and during general anesthesia induced with propofol and maintained with xenon, 59 ± 0%. Absolute quantification of MBF was started after the calculated plasma concentration of propofol had decreased to less than 1.5 μg · ml⁻¹. Results Compared with baseline (MBFbaseline, 1.03 ± 0.09 ml · min⁻¹ · g⁻¹; mean ± SD), MBF was decreased insignificantly by xenon (MBFxenon, 0.80 ± 0.22 ml · min⁻¹ · g⁻¹; -21%, P = 0.11). Xenon decreased the rate-pressure product (RPP; heart rate × systolic arterial pressure), an indicator of cardiac work and myocardial oxygen consumption (-15%, P < 0.04). When correcting for the RPP, the decrease in MBF observed during xenon anesthesia was reduced to -9% (MBFcorr-xenon, 1.42 ± 0.28 ml · g⁻¹ · mmHg⁻¹ vs. MBFcorr-baseline, 1.60 ± 0.28 ml · g⁻¹ · mmHg⁻¹, P = 0.32). Xenon did not affect the dependency of MBF on the RPP. Coronary vascular resistance did not significantly change (+15 ± 23%, P = 0.18) during xenon anesthesia. Conclusions In healthy subjects, xenon has only minimal effects on coronary flow dynamics. These effects are probably of indirect nature, reflecting the decrease in myocardial oxygen consumption induced by the effects of xenon anesthesia on cardiac work.

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Harris, Katie, Scott P. Armstrong, Rita Campos-Pires, Louise Kiru, Nicholas P. Franks, and Robert Dickinson. "Neuroprotection against Traumatic Brain Injury by Xenon, but Not Argon, Is Mediated by Inhibition at the N-Methyl-d-Aspartate Receptor Glycine Site." Anesthesiology 119, no. 5 (November 1, 2013): 1137–48. http://dx.doi.org/10.1097/aln.0b013e3182a2a265.

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Abstract Background: Xenon, the inert anesthetic gas, is neuroprotective in models of brain injury. The authors investigate the neuroprotective mechanisms of the inert gases such as xenon, argon, krypton, neon, and helium in an in vitro model of traumatic brain injury. Methods: The authors use an in vitro model using mouse organotypic hippocampal brain slices, subjected to a focal mechanical trauma, with injury quantified by propidium iodide fluorescence. Patch clamp electrophysiology is used to investigate the effect of the inert gases on N-methyl-d-aspartate receptors and TREK-1 channels, two molecular targets likely to play a role in neuroprotection. Results: Xenon (50%) and, to a lesser extent, argon (50%) are neuroprotective against traumatic injury when applied after injury (xenon 43 ± 1% protection at 72 h after injury [N = 104]; argon 30 ± 6% protection [N = 44]; mean ± SEM). Helium, neon, and krypton are devoid of neuroprotective effect. Xenon (50%) prevents development of secondary injury up to 48 h after trauma. Argon (50%) attenuates secondary injury, but is less effective than xenon (xenon 50 ± 5% reduction in secondary injury at 72 h after injury [N = 104]; argon 34 ± 8% reduction [N = 44]; mean ± SEM). Glycine reverses the neuroprotective effect of xenon, but not argon, consistent with competitive inhibition at the N-methyl-d-aspartate receptor glycine site mediating xenon neuroprotection against traumatic brain injury. Xenon inhibits N-methyl-d-aspartate receptors and activates TREK-1 channels, whereas argon, krypton, neon, and helium have no effect on these ion channels. Conclusions: Xenon neuroprotection against traumatic brain injury can be reversed by increasing the glycine concentration, consistent with inhibition at the N-methyl-d-aspartate receptor glycine site playing a significant role in xenon neuroprotection. Argon and xenon do not act via the same mechanism.

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Adkina, E. A., V. L. Ayzenberg, E. S. Iakovleva, O. N. Gudilina, and A. V. Diordiev. "Combined Xenon and Epidural Anesthesia During Surgical Correction of Joint Deformities in the Lower Extremities of Children with Cerebral Palsy." General Reanimatology 16, no. 1 (March 2, 2020): 45–58. http://dx.doi.org/10.15360/1813-9779-2020-1-45-58.

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Objectives. The objective of this study is to compare diﬀerent methods of combination general and regional anesthesia based on xenon.Materials and methods. Xenon anesthesia combined with epidural block was performed in 50 children with cerebral palsy aged 3–17 years. In 30 patients xenon was used to maintain anesthesia, in 20 children xenon was combined with sevoﬂurane. We compared the process of anesthesia, the intraoperative hemodynamic parameters and cognitive status before surgery and after it.Results. The use of xenon in all studied anesthesia methods increased the cardiac performance and was associated with a stable hemodynamic proﬁle at all stages of anesthesia despite the depressive eﬀect of epidural blockade on hemodynamics. Psychological testing revealed that xenon anesthesia has no negative eﬀect on cognitive functions in children with cerebral palsy.Conclusion. Xenon anesthesia is a promising trend in anesthesia care for children with cerebral palsy. Xenon can compensate the hemodynamic depression caused by epidural anesthesia due to its cardiac stimulant property, with no neurotoxicity being a signiﬁcant beneﬁt for children with initial damage of CNS. However, anesthesia with xenon turned out to have some disadvantages. In our study, xenon showed insuﬃcient analgesic properties, had emetic properties and was associated with spirometric abnormalities. It was more diﬃcult to maintain normal ventilation parameters in young children when using xenon. Several adverse events were noted in the recovery period. These disadvantages can be partially reduced by using a combination of xenon and sevoﬂurane.

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Nagele, Peter, Laura B. Metz, and C. Michael Crowder. "Xenon Acts by Inhibition of Non–N -methyl-d-aspartate Receptor–mediated Glutamatergic Neurotransmission in Caenorhabditis elegans." Anesthesiology 103, no. 3 (September 1, 2005): 508–13. http://dx.doi.org/10.1097/00000542-200509000-00013.

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Background Electrophysiologic experiments in rodents have found that nitrous oxide and xenon inhibit N-methyl-D-aspartate (NMDA)-type glutamate receptors. These findings led to the hypothesis that xenon and nitrous oxide along with ketamine form a class of anesthetics with the identical mechanism, NMDA receptor antagonism. Here, the authors ask in Caenorhabditis elegans whether xenon, like nitrous oxide, acts by a NMDA receptor-mediated mechanism. Methods Xenon:oxygen mixtures were delivered into sealed chambers until the desired concentration was achieved. The effects of xenon on various behaviors were measured on wild-type and mutant C. elegans strains. Results With an EC50 of 15-20 vol% depending on behavioral endpoint, xenon altered C. elegans locomotion in a manner indistinguishable from that of mutants in glutamatergic transmission. Xenon reduced the frequency and duration of backward locomotion without altering its speed or other behaviors tested. Mutation of glr-1, encoding a non-NMDA glutamate receptor subunit, abolished the behavioral effects of xenon; however, mutation of nmr-1, which encodes the pore-forming subunit of an NMDA glutamate receptor previously shown to be required for nitrous oxide action, did not significantly alter xenon response. Transformation of the glr-1 mutant with the wild-type glr-1 gene partially restored xenon sensitivity, confirming that glr-1 was necessary for the full action of xenon. Conclusions Xenon acts in C. elegans to alter locomotion through a mechanism requiring the non-NMDA glutamate receptor encoded by glr-1. Unlike for the action of nitrous oxide in C. elegans, the NMDA receptor encoded by nmr-1 is not essential for sensitivity to xenon.

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Banks, Paul, Nicholas P. Franks, and Robert Dickinson. "Competitive Inhibition at the Glycine Site of the N -Methyl-d-Aspartate Receptor Mediates Xenon Neuroprotection against Hypoxia–Ischemia." Anesthesiology 112, no. 3 (March 1, 2010): 614–22. http://dx.doi.org/10.1097/aln.0b013e3181cea398.

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Background The general anesthetic gas xenon is neuroprotective and is undergoing clinical trials as a treatment for ischemic brain injury. A small number of molecular targets for xenon have been identified, the N-methyl-D-aspartate (NMDA) receptor, the two-pore-domain potassium channel TREK-1, and the adenosine triphosphate-sensitive potassium channel (KATP). However, which of these targets are relevant to acute xenon neuroprotection is not known. Xenon inhibits NMDA receptors by competing with glycine at the glycine-binding site. We test the hypothesis that inhibition of the NMDA receptor at the glycine site underlies xenon neuroprotection against hypoxia-ischemia. Methods We use an in vitro model of hypoxia-ischemia to investigate the mechanism of xenon neuroprotection. Organotypic hippocampal brain slices from mice are subjected to oxygen-glucose deprivation, and injury is quantified by propidium iodide fluorescence. Results We show that 50% atm xenon is neuroprotective against hypoxia-ischemia when applied immediately after injury or after a delay of 3 h after injury. To validate our method, we show that neuroprotection by gavestinel is abolished when glycine is added, confirming that NMDA receptor glycine site antagonism underlies gavestinel neuroprotection. We then show that adding glycine abolishes the neuroprotective effect of xenon, consistent with competitive inhibition at the NMDA receptor glycine site mediating xenon neuroprotection. Conclusions We show that xenon neuroprotection against hypoxia- ischemia can be reversed by increasing the glycine concentration. This is consistent with competitive inhibition by xenon at the NMDA receptor glycine site, playing a significant role in xenon neuroprotection. This finding may have important implications for xenon's clinical use as an anesthetic and neuroprotectant.

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Nakata, Yoshinori, Takahisa Goto, and Shigeho Morita. "Effects of Xenon on Hemodynamic Responses to Skin Incision in Humans." Anesthesiology 90, no. 2 (February 1, 1999): 406–10. http://dx.doi.org/10.1097/00000542-199902000-00013.

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Background The authors evaluated the hemodynamic suppressive effects of xenon in combination with sevoflurane at skin incision in patients undergoing surgery. Methods Forty patients were assigned randomly to receive one of the following four anesthetics: 1.3 minimum alveolar concentration (MAC) sevoflurane, 0.7 MAC xenon with 0.6 MAC sevoflurane, 1 MAC xenon with 0.3 MAC sevoflurane, or 0.7 MAC nitrous oxide with 0.6 MAC sevoflurane (n = 10 each group). Systolic blood pressure and heart rate were measured before anesthesia, before incision, and approximately 1 min after incision. Results The changes in hemodynamic variables in response to incision were less with sevoflurane in combination with xenon and nitrous oxide than with sevoflurane alone. Changes in heart rate (in beats/min) were 19+/-11 (+/- SD) for sevoflurane alone, 11+/-6 for 0.7 MAC xenon-sevoflurane, 4+/-4 for 1 MAC xenon-sevoflurane, and 8+/-7 for nitrous oxide-sevoflurane. Changes in systolic blood pressure were 35+/-18 mmHg for sevoflurane alone, 18+/-8 mmHg for 0.7 MAC xenon-sevoflurane, 16+/-7 mmHg for 1 MAC xenon-sevoflurane, and 14+/-10 mmHg for nitrous oxide-sevoflurane. Conclusions Xenon and nitrous oxide in combination with sevoflurane can reduce hemodynamic responses to skin incision compared with sevoflurane alone. One probable explanation may be that xenon has analgesic properties similar to those of nitrous oxide, although the exact mechanism is yet to be determined.

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Kratzer, Stephan, Corinna Mattusch, Eberhard Kochs, Matthias Eder, Rainer Haseneder, and Gerhard Rammes. "Xenon Attenuates Hippocampal Long-term Potentiation by Diminishing Synaptic and Extrasynaptic N -methyl-D-aspartate Receptor Currents." Anesthesiology 116, no. 3 (March 1, 2012): 673–82. http://dx.doi.org/10.1097/aln.0b013e3182475d66.

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Background The memory-blocking properties of general anesthetics are of high clinical relevance and scientific interest. The inhalational anesthetic xenon antagonizes N-methyl-D-aspartate (NMDA) receptors. It is unknown if xenon affects long-term potentiation (LTP), a cellular correlate for memory formation. In hippocampal brain slices, the authors investigated in area CA1 whether xenon affects LTP, NMDA receptor-mediated neurotransmission, and intracellular calcium concentrations. Methods In sagittal murine hippocampal brain slices, the authors investigated the effects of xenon on LTP by recording excitatory postsynaptic field potentials. Using fluorometric calcium imaging, the authors tested the influence of xenon on calcium influx during high-frequency stimulation. In addition, using the patch-clamp technique, the xenon effect on synaptic and extrasynaptic NMDA receptors and L-type calcium channels was examined. Results In the absence of xenon, high-frequency stimulation reliably induced LTP and potentiated field potential slopes to (mean ± SEM) 127.2 ± 5.8% (P < 0.001). In the presence of xenon, high-frequency stimulation induced only a short-term potentiation, and field potentials returned to baseline level after 15-20 min (105.9 ± 2.9%; P = 0.090). NMDA receptor-mediated excitatory postsynaptic currents were reduced reversibly by xenon to 65.9 ± 9.4% (P = 0.007) of control. When extrasynaptic receptors were activated, xenon decreased NMDA currents to 58.2 ± 5.8% (P < 0.001). Xenon reduced the increase in intracellular calcium during high-frequency stimulation without affecting L-type calcium channels. Conclusions N-methyl-D-aspartate receptor activation is crucial for the induction of CA1 LTP. Thus, the depression of NMDA receptor-mediated neurotransmission presumably contributes to the blockade of LTP under xenon. Because LTP is assumed to be involved in learning and memory, its blockade might be a key mechanism for xenon's amnestic properties.

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Journal articles on the topic 'Xenodon'

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