A topological study of contextuality and modality in quantum mechanics Domenech, Graciela; Freytes Solari, Hector Carlos; de Ronde, Christian Kochen-Specker theorem rules out the non-contextual assignment of values to physical magnitudes. Here we enrich the usual orthomodular structure of quantum mechanical propositions with modal operators. This enlargement allows to refer consistently to actual and possible properties of the system. By means of a topological argument, more precisely in terms of the existence of sections of sheaves, we give an extended version of Kochen-Specker theorem over this new structure. This allows us to prove that contextuality remains a central feature even in the enriched propositional system.

Larnax altomayoense y Larnax chotanae (Solanaceae) dos nuevas especies de los bosques montanos del Norte del Perú; Larnax altomayoense y Larnax chotanae (Solanaceae) two new species from montane forests of Northern Peru Leiva González, Segundo; Pereyra Villanueva, Erwin; Barboza, Gloria Estela Se describen Larnax altomayoense y Larnax chotanae (Solanaceae) dos nuevas especies de los Bosques Montanos del Norte del Perú. Larnax altomayoense S. Leiva & Quipuscoa propia del Bosque de Protección del Alto Mayo, ruta entre el poblado de Aguas Verdes-Santa Rosa del Alto Mayo, Prov. Rioja, Dpto. San Martín, Perú, entre los 980-1010 m de elevación, se caracteriza por las flores 1-2 por nudo, cáliz rodeado por una cobertura de pelos glandulares transparentes externa e interiormente, corola campanuladaestrellada, glabra externa e interiormente, lóbulos corolinos lila-intenso cerca del 90% del área central con los bordes verdoamarillentos, lustrosos interiormente, filamentos estaminales homodínamos, cremosos, anteras morado-intenso, ovario con algunas pintas lilas longitudinales en la mitad distal, estilo exerto, baya cónica, semillas 88-95 por baya, arbustos de (0,70-) 1,20-1,50 m de alto y Larnax chotanae S. Leiva, Pereyra & Barboza habita en el bosque El Pargo (ruta Llama-Huambos), Prov. Chota, Dpto. Cajamarca, Perú, alrededor de los 3050 m de elevación, presenta las flores (2-) 3-4 por nudo, corola campanulada-estrellada, amarillo externamente, verdoso interiormente, limbo de 12-14 mm de diámetro en la antésis, estambres exertos, filamentos estaminales homodínamos, amarillos, anteras moradas, estilo exerto, amarillento, baya cónica amarillento-anaranjada, semillas 22-49 por baya, esclerosomas 12- 14 por baya, arbustos de 1,20-1,50 m de alto. Adicionalmente a las descripciones se presentan las ilustraciones correspondientes, se discuten sus relaciones con otras especies afines e incluyen datos sobre su distribución geográfica, ecología y situación actual.

Analysis of sequence configurations of the PKR-interacting HCV proteins from plasma and PBMC as predictors of response to interferon-alpha and ribavirin therapy in HIV-coinfected patients Bolcic, Federico Martin; Bull, L.; Martinez, L.; Reynoso, Rita Paola; Salomon, H.; Arduino, R.; Barnett, B.; Quarleri, Jorge Fabian Antecedentes: El tratamiento basado en interferon es una terapia estándar contra la hepatitis C crónica en pacientes coinfectados con el VIH. Exploramos el rol de dos regiones genómicas del HCV en la respuesta al IFN entre los pacientes coinfectados HIV-HCV. A través de una cohorte homogénea retrospectiva, evaluamos la frecuencia de las mutaciones E2 y NS5A en pacientes con y sin respuesta viral sostenia a la terapia basada en IFN. Métodos: Se individualizaron restrospectivamente las muestras de una cohorte homogenea de 10 pacientes coinfectados con HCV-VIH que completaron la terapia con IFN. Todos los pacientes estaban bajo tratamiento con la terapia HAART. El genotipo del HCV (basado en 5?NCR+NS5B relacionado filogenéticamente) y los análisis genómicos E2/NS5A se realizaron en compartimentos con muestras de suero y PBMC. Se analizaron las mutaciones carboxiterminales de E2, incluyendo el dominio homólogo de fosforilación PKR/eIF2alfa (PePhD) y las mutaciones de dominio unidas a la proteina kinasa de 5A no estructurado (PKRBD). Resultados: Cuatro pacientes lograron una respuesta viral sostenida y 6 fueron no respondedores (NR). Entre los pacientes con respuesta viral sostenida, los genotipos eran Gt-1 (n=3) y Gt4 (n=1).  Los tratamientos fallados fueron infectados con el Gt-1 (n=5) y el Gt-2 (n=1). La distribución genotípica fue igual para ambos grupos, los que obtuvieron respuesta viral sostenida y los no respondedores (p>0.05). Entre los compartimentos, el número de mutaciones en PKRBD fue conservado, mientras que el número de mutaciones de dominio PePHD fueron significativamente menores. Los pacientes NR exhibieron casi el mismo número de mutaciones en ambos compartimentos, mientras que aquellos con respuesta viral sostenida solo demostraron mutaciones en aislados del HCV en plasma. Cuando se realizó una comparación entre pacientes, la distribución de mutación cuantitativa o cualitativa entre los compartimentos de plasma y PBMC de cada región genómica se halló que era casi similar. Conclusiones: La frecuencia de mutaciones en las regiones definidas de la envoltura 2 del HCV PePHD y la proteina 5A no estructurada (NS5A) parece no influenciar la capacidad de IFN-alfa para bloquear la replicación del HCV ni tampoco predecir fehacientemente el resultado del tratamiento en pacientes coinfectados con VIH/HCV.

Chitosan influence on glucose and calcium availability from yogurt: In vitro comparative study with plants fibre Rodriguez, Maria Susana; Montero, Mirta Ester; Dello Staffolo, Marina; Martino, Miriam Nora; Bevilacqua, Alicia Eva; Albertengo, Liliana Since chitosan complies with the definition of dietary fibre is necessary to study the interaction of this biopolymer with nutrients. Yogurt with fortified chitosan and different types of plants fibres like wheat, bamboo, apple, psyllium and inulin was used as a food model. The availabilities of glucose and calcium in this model were studied by an in vitro gastrointestinal tract simulation. Results showed that the different fibres decreased both glucose and calcium availabilities whereas the effect of chitosan was more pronounced. (17.7 ± 2.1% and 21.0 ± 2.5% depress respectively). This work demonstrated that the addition of chitosan to yogurts influences the availability of nutrients.

Nonequilibrium critical dynamics of the three-dimensional gauge glass Romá, Federico José; Domínguez, Daniel We study the nonequilibrium aging behavior of the gauge glass model in three dimensions at the critical temperature. We perform Monte Carlo simulations with a Metropolis update, and correlation and response functions are calculated for different waiting times. We obtain a multiplicative aging scaling of the correlation and response functions, calculating the aging exponent b and the nonequilibrium autocorrelation decay exponent λc/z c. We also analyze the fluctuation-dissipation relationship at the critical temperature, obtaining the critical fluctuation-dissipation ratio X∞. By comparing our results with the aging scaling reported previously for a model of interacting flux lines in the vortex-glass regime, we found that the exponents for both models are very different.

Regulation of testosterone degradation in Comamonas testosteroni Linares, Mauricio Adrián; Pruneda Paz, Jose Luis Pablo; Reyna, Luciana; Genti de Raimondi, Susana Recently, we have identified a gene encoding a LuxR-type factor, TeiR (Testosterone-inducible Regulator), which positively regulates steroid degradation in Comamonas testosteroni. Herein, we demonstrate that TeiR interacts in vivo with steroid catabolic gene promoters. The presence of testosterone induces a significant TeiR protein increase at the early logarithmic phase of growth. Interestingly, it is not until the early stationary phase where the activation of a steroid-inducible gene promoter is observed, indicating that testosterone might not be the true inductor of the steroid degradation pathway. In addition, β-galactosidase expression driven by a testosterone-inducible promoter is prematurely activated in cells cultured in medium supplemented with ethyl acetate extracts obtained from the early stationary phase cell-free supernatants of C. testosteroni grown in presence of testosterone. Complementation experiments of C. testosteroni wild type performed with teiR deletion constructs indicate that extra-copies of deleted-TeiR exert a dominant negative effect on the wild-type TeiR protein. While, when C. testosteroni teiR mutants were used to carry out complementation assays only the full length gene can overcome the teiR mutant phenotype. Altogether these findings indicate that TeiR regulates steroid catabolic genes interacting with their promoters and suggest that this interaction requires the presence of a testosterone-derived metabolite to induce the system.

Self-monitoring of blood glucose in type 2 diabetes: an inter-country comparison Davis, W. A.; Bot, S.; Davis, T. M. E.; Farmer, A.; Gagliardino, Juan Jose; Giorda, C.; Home, P. D.; Jermendy, G.; Ji, L.; Johnson, Jeff; Karter, A. J.; Kolb, H.; Martin, S.; Mohan, V.; Nicolucci, A.; Porta, M.; Ramachandran, A.; Ramaiya, K. L.; Shah, J. H.; Shera, A. S.; Skeie, S. Self-monitoring of blood glucose (SMBG) in type 2 diabetic patients was compared across 14 countries. There was an unexpectedly high SMBG-use in non-insulin-treated patients. Reimbursement polices differed by country, region, insurance status, and patient income. More rigorous and systematic data collection is needed to ensure evidence-based SMBG-use

Aplicación de redes neuronales artificiales para la predicción de calidad de aire Chiarvetto Peralta, Lucila Lourdes; Rey Saravia, Fernando Anibal; Brignole, Nélida Beatriz Se llevó a cabo la implementación de un predictor para el promedio diario de material particulado (PM) y el diseño y desarrollo de este software es descrito en este trabajo. El daño producido por el PM en la salud humana, está relacionado con el pequeño tamaño de las partículas. Las redes neuronales artificiales (RNs) han mostrado ser un método eficiente y universal en la aproximación de funciones para cualquier tipo de dato. Una RN fue escogida porque se ha demostrado que son eficaces cuando son aplicadas a predicciones de la calidad de aire. En comparación con otros trabajos similares, sólo una red fue realizada, pero varios prototipos fueron desarrollados y evaluados para evitar la arbitrariedad en las decisiones de diseño. Se experimentaron tres aspectos en particular del diseño de una RN: la normalización de los datos, la selección de la arquitectura y la selección de la función de activación. En base a nueve variables de entrada: dos estacionales, y siete meteorológicas; se determinó que la mejor candidata es una RN compuesta por: una capa de entrada lineal de nueve neuronas artificiales (NA), una capa oculta de catorce NA y una capa de salida de una NA; ambas con una función de activación tangente hiperbólica. Durante el desarrollo de un sistema de Data Warehousing (DW) para el monitoreo y control de polución en la ciudad de Bahía Blanca (Pcia. de Buenos Aires, Argentina), el conjunto de requerimientos incluía la necesidad de contar con herramientas que permitan la predicción de las concentraciones de varios contaminantes. En el futuro, esta herramienta terminada podrá ser embebida en dicho DW. Este trabajo es el comienzo del desarrollo de un entorno de predicción más complejo que abarcará diversos contaminantes en aire.

Crustal collapse in the Andean backarc since 2 Ma: Tromen volcanic plateau, Southern Central Andes (36°40′-37°30′S) Folguera Telichevsky, Andres; Bottesi, Germán; Zapata, Tomás; Ramos, Victor Alberto Analysis of seismic lines and gravity data shows the existence of Quaternary extensional depocenters beneath thick covers of < 1 Ma-old volcanic rocks in the Tromen volcanic plateau backarc region (36°40′-37°30′S). Dating and mapping of pre- and post-extensional volcanic units and structure in this area indicate that the main phase of crustal collapse developed during the 1.7-0.7 Ma time interval. However, Late Quaternary reactivations of the extensional structure show that this process is still going on, perhaps with decreasing intensity. Moreover, identification of "mechanical" rift zones and a potentially related main thermal anomaly leads to propose that an east-dipping detachment exists beneath the Late Cretaceous-Late Miocene fold and thrust belt, controlling the crustal collapse at these latitudes. The southernmost Central Andes (35°-37°30′S) have undergone a period of shallow subduction from ~ 13 to ~ 5 Ma, that led to expansion of the arc toward the foreland, generation of ductile-fragile crustal transitions, and subsequent foreland imbrications more than 550 km away from the trench. This framework shifted to a normal Andean subduction type after ~ 5 Ma, and the arc front re-established in the present western position. The consequences of this readjustment were: a) widespread volcanic eruptions of intra-plate melts in the eastern backarc (foreland plateau flows), and b) a major trough formed between the arc front and the foreland plateau basalts (Las Loicas trough). This extensional basin controlled the emplacement of crustal melts as well as primary mantle-derived products, well represented in the Tromen volcanic plateau.

Electrochemical evaluation of multilayer silica-metacrylate hybrid sol-gel coatings containing bioactive particles on surgical grade stainless steel Ballarre, Josefina; López, Damián; Rosero, Nataly C.; Durán, Alicia; Aparicio, Mario; Ceré, Silvia Metallic materials are the most used materials as orthopaedic or dental implants because of their excellent mechanical properties. However they are not able to create a natural bonding with the mineralized bone and occasionally suffer localized corrosion. This work describes the electrochemical behaviour of a system of coatings with the addition of bioactive particles of the system SiO2-CaO-P2 O5, that enhance the abilities of the implant to make an union with the existing bone and to resist the extreme environment that are exposed to. The coatings were obtain from two kind of sols that were made by sol-gel process: one, using tetraethoxysilane (TEOS) and methyl triethoxysilane (MTES) as precursors, and the other using hydroxyethyl methacylate (HEMA), tetraethoxysilane (TEOS) and 3-methacryloxypropyl-trimethoxysilane (γMPS) [TMH] as precursor. Coatings were made in two layers. The inner layer was prepared either using TEOS and MTES (that had already shown good anticorrosion properties), or TMH. The top layer was made with TMH with the addition of 10% in weight of small (diameter less than 20 μm) or big (more than 20 μm) bioactive particles. The samples were tested in vitro by polarization curves and electrochemical impedance spectroscopy (EIS) assays. The samples with the two kind of coatings seem to have a protective behaviour after 30 days of immersion due to the compact TEOS-MTES inner layer. The big particles placed in the outer layer showed a dissolution rate similar to the rate of deposition of the amorphous hydroxyapatite (aHAp) at the surface, blocking the entrance of the electrolyte, avoiding it to reach the substrate. The TMH coatings with small particles present a similar behaviour to the naked material, allowing the electrolyte to reach the metal. The dual coating with this kind of particles has similar characteristics, with a "sponge-like" behaviour, and the inner coating probably develops flaws due to the fast dissolution of the small particles placed in the upper layer. © 2008 Elsevier B.V. All rights reserved.

Open-field temporal pattern of ambulation in Japanese quail genetically selected for contrasting adrenocortical responsiveness to brief manual restraint Kembro, Jackelyn Melissa; Satterlee, Daniel G.; Schmidt, J. B.; Perillo, Maria Angelica; Marin, Raul Hector Japanese quail selected for a low-stress (LS), rather than a high-stress (HS), plasma corticosterone response to brief restraint have been shown to possess lower fearfulness and a nonspecific reduction in stress responsiveness. Detrended fluctuation analysis provides information on the organization and complexity of temporal patterns of behavior. The present study evaluated the temporal pattern of ambulation of LS and HS quail in an open field that represented a novel environment. Time series of 4,200 data points were collected for each bird by registering the distance ambulated every 0.5 s during a 35-min test period. Consistent with their known reduced fearfulness, the LS quail initiated ambulation significantly sooner (P < 0.02) and tended to ambulate more (P < 0.09) than did their HS counterparts. Detrended fluctuation analyses showed a monofractal series (i.e., a series with similar complexity at different temporal scales) in 72% of the birds. These birds initiated their ambulatory activity in less than 600 s. Among these birds, a lower (P < 0.03) autosimilarity coefficient (α) was found in the LS quail than in their HS counterparts (α = 0.76 ± 0.03 and 0.87 ± 0.03, respectively), suggesting a more complex (less regular) ambulatory pattern in the LS quail. However, when the patterns of ambulation were reexamined by considering only the active period of the time series (i.e., after the birds had initiated their ambulatory activity), monofractal patterns were observed in 97% of the birds, and no differences were found between the lines. Collectively, the results suggest that during the active period of open-field testing, during which fear responses are likely less strong and other motivations are the driving forces of ambulation, the LS and HS lines have similar ambulatory organization.

Simultaneous untangling and smoothing of moving grids Lopez, Ezequiel Jose; Nigro, Norberto Marcelo; Storti, Mario Alberto In this paper a technique for simultaneous untangling and smoothing of meshes is presented. Itis based on an extension of an earlier mesh smoothing strategy developed by the authors and used to solve the computational mesh dynamics stage in fluid-structure interaction problems. In moving grid problems, mesh untangling is necessary when element inversion happens due to a moving domain boundary. The original smoothing strategy is defined in terms of the minimization of a functional associated with the mesh distortion using an indicator of the element geometric quality. This functional becomes discontinuous when an element has null volume, making impossible to obtain a valid mesh from an invalid one. To circumvent this drawback, the original functional is transformed in order to guarantee its continuity for the whole space of nodal coordinates, achieving the untangling technique. The regularization depends on one parameter, allowing the recovery of the original functional when this parameter tends to zero. This feature is very important because at first it is necessary to regularize the functional in order to make the mesh valid, but then, it is advisable to use the original functional to make the smoothing optimal. This technique is applied to several test cases, including 2D and 3D meshes with simplicial elements. An additional example shows how this technique may be used for mesh generation.

Nitric oxide system alteration at spinal cord as a result of perinatal asphyxia is involved in behavioral disabilities: hypothermia as preventive treatment Dorfman, Verónica Berta; Rey Funes, Manuel; Bayona, Julio César; Lopez, Ester Maria; Coirini, Hector; Loidl, Cesar Fabian Perinatal asphyxia (PA) is able to induce sequelae such as spinal spasticity. Previously, we demonstrated hypothermia as a neuroprotective treatment against cell degeneration triggered by increased nitric oxide (NO) release. Because spinal motoneurons are implicated in spasticity, our aim was to analyze the involvement of NO system at cervical and lumbar motoneurons after PA as well as the application of hypothermia as treatment. PA was performed by immersion of both uterine horns containing full-term fetuses in a water bath at 37 degrees C for 19 or 20 min (PA19 or PA20) or at 15 degrees C for 20 min (hypothermia during PA-HYP). Some randomly chosen PA20 rats were immediately exposed for 5 min over grain ice (hypothermia after PA-HPA). Full-term vaginally delivered rats were used as control (CTL). We analyzed NO synthase (NOS) activity, expression and localization by nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) reactivity, inducible and neuronal NOS (iNOS and nNOS) by immunohistochemistry, and protein nitrotyrosilation state. We observed an increased NOS activity at cervical spinal cord of 60-day-old PA20 rats, with increased NADPH-d, iNOS, and nitrotyrosine expression in cervical motoneurons and increased NADPH-d in neurons of layer X. Lumbar neurons were not altered. Hypothermia was able to maintain CTL values. Also, we observed decreased forelimb motor potency in the PA20 group, which could be attributed to changes at cervical motoneurons. This study shows that PA can induce spasticity produced by alterations in the NO system of the cervical spinal cord. Moreover, this situation can be prevented by perinatal hypothermia.

Murine abortion is associated with enhanced Hyaluronan expression and abnormal localization at the fetomaternal interface Cordo Russo, Rosalia Ines; García, Mariana Gabriela; Barrientos, Gabriela Laura; Orsal, A. S.; Viola, M.; Moschansky, Petra; Ringel, F.; Passi, A.; Alaniz, Laura Daniela; Hajos, Silvia Elvira; Blois, Sandra M. The remodelling of the endometrial architecture is fundamental to create a suitable environment for the establishment of pregnancy. During this process, substantial alterations in the composition of maternal extracellular matrix play an important role by providing a prosperous medium for implantation as well as modulating trophoblast invasion leading to the formation of a functional placental unit. Hyaluronan is a conspicuous component of the extracellular matrix, particularly in remodelling tissues undergoing regeneration and repair. During gestation, changes in HA deposition and distribution indicate that this molecule may participate in preparation of the endometrial stroma for reception and implantation of the embryo. However, little is known about the role of hyaluronan at the fetomaternal interface, specially regarding its influence in pregnancy outcome. In the present study we show increased decidual hyaluronan levels in spontaneous abortion compared with normal pregnancy mice on gestation day 7.5. Both in normal and pathologic pregnancies, high molecular size hyaluronan was found at the fetomaternal unit. However, hyaluronan metabolism (which results from the activity of hyaluronan synthases and hyaluronidases) seems to be altered in spontaneous abortion as shown by a decrease in Hyal-3 expression as well as by differences in hyaluronan molecular size spectrum. This alteration in hyaluronan metabolism in spontaneous abortion could explain its increased concentration observed in decidua and the abnormal distribution of hyaluronan around the embryo implantation crypt. Thus, increased decidual hyaluronan levels resulting from abnormal deposition and turn over may contribute to the pathogenesis of pregnancy failure.

Involvement of c-Src tyrosine kinase in SHP-1 phosphatase activation by Ang II AT2 receptors in rat fetal tissues Alvarez, Sergio Eduardo; Seguin, Leonardo Roque; Villarreal, Rodrigo Sebastian; Nahmias, Clara; Ciuffo, Gladys Maria Angiotensin II (Ang II) AT2 receptors are abundantly expressed in rat fetal tissues where they probably contribute to development. In the present study we examine the effects of Ang II type 2 receptor stimulation on SHP-1 activation. Ang II (10-7 M) elicits a rapid and transient tyrosine phosphorylation of SHP-1, maximal at 1 min, in a dose-dependent form, blocked by the AT2 antagonist, PD123319. SHP-1 phosphorylation is followed in time by tyrosine dephosphorylation of different proteins, suggesting a sequence of events. Ang II induces association of SHP-1 to AT2 receptors as shown by co-immunoprecipitation, Western blot and binding assays. SHP-1 activity was determined in immunocomplexes obtained with either anti-AT2 or anti-SHP-1 antibodies, after Ang II stimulation (1 min), in correlation with the maximal level of SHP-1 phosphorylation. Interestingly, following receptor stimulation (1 min) c-Src was associated to AT2 or SHP-1 immunocomplexes. Preincubation with the c-Src inhibitor PP2 inhibited SHP-1 activation and c-Src association, thus confirming the participation of c-Src in this pathway. We demonstrated here for the first time the involvement of c-Src in SHP-1 activation via AT2 receptors present in an ex vivo model expressing both receptor subtypes. In this model, AT2 receptors are not constitutively associated to SHP-1 and SHP-1 is not constitutively activated. Thus, we clearly establish that SHP-1 activation, mediated by the AT2 subtype, involves c-Src and precedes protein tyrosine dephosphorylation, in rat fetal membranes.

Mechanochemical activation of a titanium-magnetite mixture: Mössbauer spectroscopy study Cristobal, Adrian Alberto; Aglietti, Esteban Fausto; Porto Lopez, Jose Manuel; Sives, Flavio Rubén; Mercader, Roberto Carlos Mechanochemical activation has become a valuable tool in the design and synthesis of novel materials, due to the increased reactivity of activated solids, and the possibility of synthesizing metastable phases not obtainable by conventional methods. In this work, ac magnetic susceptibility, Mössbauer spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy have been employed to study the structural and thermal evolution of a mechanochemically activated Ti-Fe3O4 mixture, with molar ratio Ti:Fe3O4 of 1:2. Upon activation in a high-energy planetary mill, the mixtures undergoes a redox reaction, in which the Ti reduces the Fe ions of the spinel, resulting in a solid solution of variable composition between magnetite (Fe3O4) and ulvospinel (TiFe2O4). The activation results in changes in the magnetic behavior of the mixture, and loss of crystallinity. Mössbauer spectroscopy and XRD show the progressive disappearance of the original phases, and the formation of Fe0, Fe2O3 and ulvospinel. © 2008 Elsevier Ltd. All rights reserved.

Determinación de la actividad de la oxido nítrico sintetasa endotelial y del factor NF-kB, en piel de pacientes con Pseudoangiomatosis eruptiva; Factor-ĸb expression and endothelial nitric oxide synthase activity in eruptive pseudoangiomatosis lesions Parra, Verónica Ester; Miatello, Roberto Miguel; Renna, Nicolas Federico; Driban, N.; Rivarola, Emilce La pseudoangiomatosis eruptiva se caracteriza por la aparición brusca de múltiples pápulas eritematosas, asintomáticas, rodeadas de un halo blanquecino, con remisión espontánea. Histológicamente se observa dilatación vascular con escaso infiltrado inflamatorio. Su etiología permanece incierta a pesar de ser relacionada con virus o picaduras de insectos. Basados en el compromiso vascular, el objetivo del trabajo fue investigar la actividad de la enzima endotelial oxido nítrico sintetasa (eNOS) y la expresión del factor NF-kB por inmunohistoquimica en un intento de esclarecer su patogenia. Material y métodos: Se estudiaron diez pacientes con diagnóstico clínico de pseudoangiomatosis eruptiva (PAE) que presentaron la dermatosis en forma epidémica. Se realizaron biopsias teñidas con Hematoxilina-Eosina y Tricrómico de Masson. Se efectuó estudio virológico de los pacientes Nª 4, 9 y 10 mediante determinaciones serológicas para echovirus, enterovirus, citomegalovirus, parvovirus B19 y hepatitis A, B y C. En cinco pacientes se obtuvo material para determinación de eNOS y NF-kB. Resultados: Todos los pacientes, 5 hombres y 5 mujeres presentaron pápulas eritematosas rodeadas por un halo blanquecino, especialmente en las extremidades, alrededor de las rodillas. Histológicamente mostraron vasos dilatados y células endoteliales prominentes con un infiltrado discreto perivascular. Todos los estudios serológicos fueron negativos. La actividad de eNOS fue significativamente menor comparada con la piel normal (p= 0,002) y la expresión de NF- ĸB fue fuertemente positiva en los vasos de la dermis papilar y reticular. Conclusiones: Todos los pacientes fueron afectados en verano, por lo que la picadura del mosquito debe ser considerada como un factor etiológico. La baja expresión de eNOS está relacionada con la vasodilatación y la expresión aumentada de NF-ĸB confirma que el proceso es de tipo inflamatorio.; Eruptive pseudoangiomatosis (EPA) is a dermatosis characterized by sparse erythematous papules, with vascular appearance and surrounded by a blanching halo. It has acute onset and spontaneous resolution. Histopathology shows vascular affection. Though it has been related to viral infection and insects bites its aetiology and pathogenesis remains unclear. Based on clinical and histological findings, related to vascular affection, the main objective was to observe changes in endothelial nitric oxide synthase (eNOS) activity and nuclear factor-ĸ B (NF-kB) expression related to inflammatory pathogenesis. Materials and methods: Samples from ten patients with clinical diagnosis of EPA were fixed for light microscopy in formalin solution, embedded in paraffin and stained with haematoxylin and eosin and Masson´s trichrome stain. In three patients serological testing for echovirus, enterovirus, cytomegalovirus, parvovirus A and B, hepatitis C and hepatitis B virus were performed. eNOS activity: in five patients snap-frozen tissue was obtained and homogenized in a buffer containing 250 mM sucrose, 50 mM tris-HCl pH 7.4 and added protease inhibitors: SBTI, aprotinin, PMSF, leupeptin, DTT and EDTA. The activity was evaluated in the supernatant measuring the conversion of L-[3H]-arginine in L-[3H]- citruline and subsequent liquid scintillation counting. 4. Expression of NF-ĸB, a promoter of inflammatory processes activated by redox status was determined by immunohistochemistry. Results: The patients, 5 women and 5 men, had 3 to 6 mm, red papules surrounded by a 2 to 5 mm blanching halo, especially located on the lower extremities, around knees, 5 5 forearms and arms. In two patients the lesions were also on the trunk and face. Histological findings show dilated dermal blood vessels with plump endothelial cells and perivascular lymphohistiocytic infiltrate. All serological tests for virus were negative. eNOS activity in lesions was significant lower when compared with normal skin (p= 0,002). NF-ĸB expression was strongly positive in dermal vessels of the papillary and reticular dermis. Conclusions: As all our patients were affected in summer, mosquito bites must be considered as etiologic factor. eNOS lower expression suggests that probably it has no role in this inflammatory process, but linked to blood stasis. The increased expression of NF-ĸB confirms that the inflammatory process is related to the developing process.

Análisis cromosómico aplicado a la diferenciación de Lotus glaber y L. corniculatus (Fabaceae) Celotto, Adriana Inés; Sanso, Andrea Mariel En la región de la pampa deprimida, debido al déficit de leguminosas nativas de los pastizales naturales, Lotus tenuis Waldst & Kit. y L. corniculatus L. son utilizadas como especies forrajeras por sus buenas cualidades nutritivas y preferencia animal. Se trata de especies de gran interés agronómico, estrechamente relacionadas, con gran similitud fenotípica pero con distintas aptitudes forrajeras, ecológicas y valor económico. Las semillas de estas especies de Lotus no manifiestan características macromorfológicas que permitan diferenciarlas. Tampoco pueden ambas especies identificarse tempranamente en forma concluyente, considerando las  características morfológicas de las plántulas. Nuestra investigación surge como respuesta a la necesidad de diferenciar estas dos especies en el estado de semilla o durante la germinación utilizando metodologías que resulten suficientemente rápidas, confiables, económicas y reproducibles. Para ello, se llevaron a cabo estudios cromosómicos. Se lograron estandarizar las técnicas citogenéticas para estudiar cromosómicamente a L. tenuis (2n = 12) y a L. corniculatus (2n = 24). Los cultivares estudiados resultaron ser homogéneos en relación al número cromosómico aunque se encontraron algunos individuos con números diferentes. El análisis de  muestras provistas por laboratorios privados reveló que se distribuye bajo distintas denominaciones la misma especie. Suele comercializarse  L. corniculatus  bajo la denominación de L. tenuis. El análisis cromosómico, brinda resultados rápidos, confiables y reproducibles para la diferenciación específica entre ambas especies. Las técnicas citogenéticas utilizadas podrían implementarse en laboratorios con un limitado equipamiento y un relativo bajo costo.

Weighting against homoplasy improves phylogenetic analysis of morphological data sets Goloboff, Pablo Augusto; Carpeneter, James M.; Arias Becerra, Joan Salvador; Miranda Esquivel, Daniel Rafael The problem of character weighting in cladistic analysis is revisited. The finding that, in large molecular data sets, removal of third positions (with more homoplasy) decreases the number of well supported groups has been interpreted by some authors as indicating that weighting methods are unjustified. Two arguments against that interpretation are advanced. Characters that collectively determine few well-supported groups may be highly reliable when taken individually (as shown by specific examples), so that inferring greater reliability for sets of characters that lead to an increase in jackknife frequencies may not always be warranted. But even if changes in jackknife frequencies can be used to infer reliability, we demonstrate that jackknife frequencies in large molecular data sets are actually improved when downweighting characters according to their homoplasy but using properly rescaled functions (instead of the very strong standard functions, or the extreme of inclusion ⁄ exclusion); this further weakens the argument that downweighting homoplastic characters is undesirable. Last, we show that downweighting characters according to their homoplasy (using standard homoplasy-weighting methods) on 70 morphological data sets (with 50?170 taxa), produces clear increases in jackknife frequencies. The results obtained under homoplasy weighting also appear more stable than results under equal weights: adding either taxa or characters, when weighting against homoplasy, produced results more similar to original analyses (i.e., with larger numbers of groups that continue being supported after addition of taxa or characters), with similar or lower error rates (i.e., proportion of groups recovered that subsequently turn out to be incorrect). Therefore, the same argument that had been advanced against homoplasy weighting in the case of large molecular data sets is an argument in favor of such weighting in the case of morphological data sets.

Actividad antioxidante de alimentos consumidos en Argentina Nazareno, Mónica Azucena; González, Evangelina A.; Garcia, Marian; Loto, Cecilia; Coria Cayupán, Yanina Soledad En la naturaleza existen muchos grupos de sustancias antioxidantes. Muchos de ellos son de origen vegetal y están ampliamente difundidos en alimentos por lo que son aportados a nuestro organismo a través de la dieta. Numerosos estudios indican que el consumo de frutas y verduras esta relacionado con menores incidencias de enfermedades cardiovasculares y algunos tipos de cáncer, sugiriendo que una dieta rica en estos alimentos ejerce efectos benéficos para la salud y éstos son asociados a la acción de sus componentes antioxidantes