Mass transfer of cadmium ions in a hollow-fiber module by pertraction Marchese, Jose; Campderrós, Mercedes Edith The facilitated transport of Cd(II) ions through a hollow-fiber-supported liquid membrane with bis-2-ethylhexyl phosphoric acid as carrier was studied. The mass transfer rate, expressed as permeability P, was measured as a function of mean aqueous solution velocity and carrier concentration. Characteristic ion permeabilities of 10-26×10-7m/s were measured at feed velocities between 1×10-2-19×10-2 m/s at stripping velocities between 0.22×10-2-7×10-2 m/s with constant feed flow. The measured permeabilities were compared to generally accepted mass transfer correlations. The predicted permeabilities adequately fit the experimental data, indicating that the rate limiting step in the transport of the ion was the diffusion through both aqueous films, feed and stripping, whereas the organic resistance of the membrane was negligible. Furthermore, the proposed model allowed the prediction of the permeability of cadmium for different experimental conditions, which is useful to perform experiments to reduce metal levels in water or other effluents.

Diagnosis of Clostridium perfringens intestinal infections in sheep and goats Uzal, Francisco Alejandro Clostridium perfringens produces disease in sheep, goats and other animal species, most of which are generically called enterotoxemias. This micro-organism can be a normal inhabitant of the intestine of most animal species including humans, but when the intestinal environment is altered by sudden changes in diet or other factors, C. perfringens proliferates in large numbers and produces several potent toxins that are absorbed into the general circulation or act locally with usually devastating effects on the host. History, clinical signs and gross post-mortem findings are useful tools for establishing a presumptive diagnosis of enterotoxaemia by C. perfringens in sheep and goats, although no definitive diagnosis of these diseases can be made without laboratory confirmation. Because all types of C. perfringens can be normal inhabitants of the intestine of most animals, culture of this micro-organism from intestinal contents of animals has no diagnostic value unless a colony count is performed and large numbers (usually more than 104–107 CFU/g) of C. perfringens are found. The most accepted criterion in establishing a definitive diagnosis of enterotoxaemia by C. perfringens is the detection of its toxins in intestinal contents. However, some of the major toxins of C. perfringens (i.e. epsilon toxin) can also be found, albeit in small amounts, in the small intestine of clinically normal sheep, and this poses a diagnostic challenge. In such cases the histopathology of the brain must be used as an alternative diagnostic tool, since the lesions produced by epsilon toxin in the brains of sheep and goats are unique and pathognomonic for C. perfringens type D enterotoxaemia. Ancillary tests, such as measurement of urine glucose or observation of Gram stained smears of intestinal mucosa can be used and, although they have a presumptive diagnostic value when positive, they cannot be used to rule out a diagnosis of enterotoxaemia if they are negative. In conclusion, the diagnosis of C. perfringens infections in animals is complex and it is appropriate to rely on a combination of diagnostic techniques rather than one singe test.

Design for Operability: A Review of Approaches and Solution Strategies; Diseño para operabilidad: Una revisión de enfoques y estrategias de solución Blanco, Anibal Manuel; Bandoni, Jose Alberto In the last decades the chemical engineering scientific research community has largely addressed the design-foroperability problem. Such an interest responds to the fact that the operability quality of a process is determined by design, becoming evident the convenience of considering operability issues in early design stages rather than later when the impact of modifications is less effective and more expensive. The necessity of integrating design and operability is dictated by the increasing complexity of the processes as result of progressively stringent economic, quality, safety and environmental constraints. Although the design-for-operability problem concerns to practically every technical discipline, it has achieved a particular identity within the chemical engineering field due to the economic magnitude of the involved processes. The work on design and analysis for operability in chemical engineering is really vast and a complete review in terms of papers is beyond the scope of this contribution. Instead, two major approaches will be addressed and those papers that in our belief had the most significance to the development of the field will be described in some detail.; En las últimas décadas, la comunidad científica de ingeniería química ha abordado intensamente el problema de diseño-para-operabilidad. Tal interés responde al hecho de que la calidad operativa de un proceso esta determinada por diseño, resultando evidente la conveniencia de considerar aspectos operativos en las etapas tempranas del diseño y no luego, cuando el impacto de las modificaciones es menos efectivo y más costoso. La necesidad de integrar diseño y operabilidad esta dictada por la creciente complejidad de los procesos como resultado de las cada vez mayores restricciones económicas, de calidad de seguridad y medioambientales. Aunque el problema de diseño para operabilidad concierne a prácticamente toda disciplina, ha adquirido una identidad particular dentro de la ingeniería química debido a la magnitud económica de los procesos involucrados. El trabajo sobre diseño y análisis para operabilidad es realmente vasto y una revisión completa en términos de artículos supera los alcances de este trabajo. En su lugar, se discutirán los dos enfoques principales y aquellos artículos que en nuestra opinión han tenido mayor impacto para el desarrollo de la disciplina serán descriptos con cierto detalle.

The Triassic-Jurassic boundary in the Andes of Argentina Riccardi, Alberto Carlos; Damborenea, Susana Ester; Manceñido, Miguel Oscar; Iglesia Llanos, Maria Paula The Arroyo Malo Formation at Alumbre Creek, on the northern bank of the Atuel River, west central Argentina, comprises a c. 300 m thick continuous marine succession across the Triassic-Jurassic System boundary, consisting of massive and laminated pelites indicative of a slope depositional environment. Late Triassic invertebrates, including ammonoids, nautiloids, bivalves, gastropods, brachiopods and corals are restricted to the lower 150 m. Beds between 125-135 m from the bottom yield Choristoceras cf. marshi Hauer, a species found in the Marshi/Crickmayi Zone of Europe and North America, together with loose fragments of Psiloceras cf. pressum Hillebrandt, coeval with the lower to middle part of the Hettangian Planorbis Zone. About 80 m higher are beds yielding Psiloceras cf. rectocostatum Hillebrandt, a species that gives name to an Andean biozone partially coeval with the Johnstoni and Plicatulum Subzones, upper Planorbis Zone. Other fossils recorded in the Rhaetian strata of this section are foraminifers, ostracods and plant remains identified as Zuberia cf. zuberi (Szaj.) Freng. and Clathropteris sp. The section was also sampled for conodonts and radiolarians, thus far with negative results. A palaeomagnetic study is underway.; La Formazione Arroyo Malo ad Alumbre creek, sulla sponda settentrionale del fiume Atuel, Argentina centro-occidentale, comprende una successione marina continua spessa circa 300 m attraverso i! limite Triassico-Giurassico, ed e costituita da peliti massive e laminate indicative di un ambiente deposizionale di scarpata. Gli inverttfjrati del Ttiassico superiore, che includono ammonoidi, nautiloidi, bivalvi, gasteropodi, brachiopodi e coralli sono limitati ai primi 150 m. Gli strati fra i 125-135 m dalla base hanno dato Choristoceras cf. marshi Hauer, una specie trovata nella Zona a Marshi/Crickmayi di Europa e Nord America, insieme con frammenti sparsi di Psiloceras cf. pressum Hillebrandt, coeva con la parte mediana della Zona a Planorbis dell'Hettangiano. Circa. 80 m piu in alto ci sono strati contenenti Psiloceras cf. rectocostatum Hlllebrandt, una specie che da i! no me ad una biozona andina parzialmente coeva con le Sottózone a Johnstoni e Plicatulum, Zona a Planorbis superiore. Altri fossili documentati negli strati del Retico di questa sezione sono foraminiferi, ostracodi e resti di piante identificati come Zuberia cf. zuberi (Szaj.) Freng. e Clathropteris sp. La sezione e stata anche campionata per quanto riguarda conodonti e radiolari, finora con risultati negativi. Uno studio paleomagnetico e in corso.

Assessment of platelet activation in myeloproliferative disorders with complementary techniques Bermejo, Emilse; Alberto, Maria Fabiana; Meschengieser, Susana S.; Lazzari, María Ángela Bleeding and thrombosis in myeloproliferative disorders (MPD) are common events, sometimes both are present in the same patient during the course of the disease. Platelet activation in patients with MPD is often suggested. The present study analyses the presence of circulating activated platelets, using simultaneously flow cytometry and aggregometric studies in MPD. We studied 28 patients: 13 with polycythaemia vera, seven with essential thrombocythaemia, and eight chronic myeloid leukaemia. We performed functional tests, aggregation and adenosine triphosphate (ATP) release and flow cytometric assays (mepacrine staining and platelet activation markers CD62, CD63 and fibrinogen binding (B-FG)). Twenty-one MPD samples (75%) had reduced aggregation and ATP release. Acquired δ-SPD was detected in 11 of 28 MPD patients (39%), and we found no association between reduced mepacrine labelling and abnormal ATP release. High levels of activation markers were obtained: CD62 in 19 of 28 patients (68%), CD63 in 13 of 28 patients (46%) and B-FG in 19 of 28 patients (68%). The most prevalent abnormality was a reduced aggregation and ATP release. The lack of association between ATP release and mepacrine labelling suggests that other mechanisms, besides the deficit of intraplatelet ATP/adenosine diphosphate, might occur. High levels of activation markers were also observed. We conclude that both tests are complementary and necessary to understand the functional status of platelets in MPD.

Yoghurt feeding inhibits promotion and progression of experimental colorectal cancer de Moreno, Maria Alejandra; Perdigon, Gabriela del Valle Background: In BALB/c mice, a yogurt diet given before and after the carcinogen 1, 2 dymethylhydrazine (DMH) inhibited colon cancer. This paper studied at which stage of tumor development (initiation, promotion or progression) yogurt exerts its antitumor activity. Material/Methods: Six experimental groups were used: 1) non-treatment control; 2) DMH control; 3) yogurt- DMH-yogurt: yogurt administered before and after DMH. 4) yogurt-DMH: yogurt given only 10 days before DMH; 5) DMH-yogurt: yogurt given cyclically after DMH; and 6) yogurt control. The groups DMH-yogurt and yogurt-DMH were compared histologically and TNFα, INFγ, IL-10 and IL-4 cytokines, CD4[sup]+[/sup]/CD25[sup]+[/sup] T cells, and apoptotic cells were determined in large intestine biopsies. TNFα and INFγ were also determined in cells isolated from large intestine nodules and from Peyer’s patches. Results: The DMH-yogurt group did not develop tumor. The yogurt-DMH group showed only tumor delay; TNFα, INFγ and IL-10 increasing in this group in all the periods assayed. These results agree with those already reported for DMH control and yogurt-DMH-yogurt. There was no correlation between the high levels of IL-10 and CD4[sup]+[/sup]/CD25+ T regulatory population. IL-4 and apoptotic cells increased in the yogurt-DMH group only in the first months. In the DMHyogurt group, cellular apoptosis increased during the whole treatment. Yogurt feeding induced TNFα and INFγ increases in cells isolated from large intestine nodules. These cytokines also increased in cells from Peyer’s patches of the yogurt control group. Conclusions: These results show that yogurt inhibited tumor progression and promotion by modulating the immune response and stimulating cellular apoptosis.

Population parameters of Spodoptera frugiperda (Smith) (Lep.: Noctuidae) fed on corn and two predominant grasess in Tucuman (Argentina) Murúa, María Gabriela; Virla, Eduardo Gabriel Se realizó un estudio comparativo en condiciones de laboratorio sobre los parámetros poblacionales de S. frugiperda alimentada con maíz (Zea mays L.) y con las dos pasturas más predominantes en Tucumán (Argentina): pasto guinea (Panicum maximum Jacq.) y gramón (Cynodon dactylon (L.) Pers.). Las dietas usadas determinaron cambios en diversos parámetros tales como duración del ciclo de vida, número de instares larvales, proporción de sexos, expectativa de vida, fertilidad y fecundidad. Teniendo en cuenta la duración de ciclo de vida, diferencias significativas entre las plantas huésped fueron registradas entre los distintos estados de desarrollo. Las hembras mostraron una fertilidad del 92,1%, 96,4% y 99,8% cuando fueron alimentadas con maíz, pasto guinea y gramón, respectivamente. La producción diaria media de huevos varió entre 99,4 para hembras alimentadas con gramón y 187,8 para las alimentadas con pasto guinea. La producción media total de huevos también varió según la dieta suministrada, el máximo valor fue registrado para las hembras que durante el estadío larval fueron alimentadas con hojas de pasto guinea (0 1282.7 ± 38.6 huevos/hembras). Los resultados sugieren que los individuos alimentados con las pasturas antes mencionadas jugarían un papel importante en el comportamiento de la dinámica poblacional de S. frugiperda afectando cultivos de maíz en la región del Norese Argentino. Estas pasturas podrían albergar a la primera generación anual de la plaga y su manejo racional podría disminuir la incidencia del cogollero sobre los cultivos de maíz.; A comparative laboratory study on population parameters of Spodoptera frugiperda (Smith) (Lep.: Noctuidae) fed on corn (Zea mays L.) and two of the most predominant grasses in Tucuman (Argentina) Guineagrass (Panicum maximum Jacq.) and Bermudagrass (Cynodon dactylon (L.) Pers.) was carried out. The diets used determined changes in diverse parameters such as duration of life cycle, number of larval instars, sex ratio, life expectancy, fertility and/or fecundity. Regarding to the life cycle duration, significant differences among host plants were recorded for the different developmental stages. Females fed on a corn diet showed a fertility of 92.1%, while those breeding on a diet based on Guineagrass showed 96.4% and 99.8% on Bermudagrass. Mean daily egg production ranged within 99.4 (fed on Bermudagrass) and 187.8 (fed on Guineagrass). Total mean egg production also varied with larval diet; maximum value was recorded for females fed on Guineagrass leaves (0 1282.7 ± 38.6 eggs/females). Results suggest that individuals bred on this grasses during final winter could play an important role in FAW population dynamic performance affecting corn crops in Argentina's Norther Region.

Continuum approach to material failure in strong discontinuity settings Oliver, J.; Huespe, Alfredo Edmundo The paper focuses the numerical modelling of material failure in a strong discontinuity setting using a continuum format. Displacement discontinuities, like fractures, cracks, slip lines, etc., are modelled in a strong discontinuity approach, enriched by a transition from weak to strong discontinuities to get an appropriate representation of the fracture process zone. The introduction of the strong discontinuity kinematics automatically projects any standard dissipative constitutive model, equipped with strain softening, into a discrete traction–separation law that is fulfilled at the discontinuity interface. Numerical issues like a global discontinuity tracking algorithm via a heat conduction-like problem are also presented. Some representative numerical simulations illustrate the performance of the presented approach.

Statistical thermodynamics of adsorbates with nonsymmetrical lateral interactions Romá, Federico José; Ramirez Pastor, Antonio Jose The exact adsorption thermodynamics of particles with nonsymmetrical ad-ad interactions on a one-dimensional space is presented. The asymmetry is introduced by considering the lateral interactions depending on the orientation of the adsorbed molecules. The adsorption process is monitored by following the adsorption isotherm, the thermodynamic factor, the differential heat of adsorption, and the configurational entropy of the adlayer. A rich variety of different behaviors is found with respect to the standard lattice gas of interacting monomers. The resulting thermodynamic description may also be applicable to adsorption and transport of nonspherical molecules in low-dimensional systems such as carbon nanotubes.

Neural cell adhesion molecule in human serum. Increased levels in dementia of the Alzheimer type Todaro, Laura Beatriz; Puricelli, Lydia Ines; Gioseffi, Hernan; Pallotta, María Guadalupe; Lastiri, José; Bal de Kier Joffe, Elisa; Varela, Mirta; Sacerdote de Lustig, Eugenia Memory impairment is a process associated with alterations in neuronal plasticity, synapses formation, and stabilization. As the neural cell adhesion molecule (NCAM) plays a key role in synaptic bond stabilization, we analyzed the usefulness of soluble NCAM isoforms in the diagnosis of patients with dementia of the Alzheimer type (DAT). NCAM was measured in the sera of 70 control subjects and 43 DAT patients (with different severity of cognitive impairment, GDS), employing Western blot and densitometric quantification. LMW-NCAM bands (100–130 kDa) decreased significantly with age independently of sex. DAT patients presented values of LMW-NCAM and HMW-NCAM significantly higher than healthy controls of similar age (higher than 130 kDa). Only LMW-NCAM was associated with GDS. Our results suggest that NCAM could be involved in the pathogenesis of DAT disorder and that serum NCAM levels could be useful as differential diagnostic markers of the disease.

Dose-dependent activity of albendazole against benzimidazole-resistant nematodes in sheep: relationship between pharmacokinetics and efficacy Moreno Torrejon, Laura; Echevarria, Flavio A. M.; Muñoz, Fabio; Alvarez, Luis Ignacio; Sanchez Bruni, Sergio Fabian; Lanusse, Carlos Edmundo The relationship between the pharmacokinetic behaviour and the anthelmintic efficacy of albendazole (ABZ) against benzimidazole (BZD)-resistant nematodes was studied in sheep. A micronized ABZ suspension was orally administered at two different dose levels to sheep naturally infected with BZD-resistant gastrointestinal (GI) nematodes. The experimental animals were allocated into the following groups (n=8): (a) untreated control; (b) orally treated with ABZ at 3.8 mg/kg b.w.; and (c) orally treated with ABZ at 7.5 mg/kg b.w. Plasma samples were obtained serially over 72 h post-treatment from both treated groups and analysed by HPLC to measure the concentrations of ABZ and its sulphoxide (ABZSO) and sulphone (ABZSO2) metabolites. Faecal egg counts were performed prior to treatment and at the necropsy day. All experimental animals were sacrificed 10 days after treatment to perform GI worm counts. While ABZ parent drug was not recovered in the bloodstream, ABZSO and ABZSO2 were the molecules found in plasma. ABZSO was the metabolite measured at the highest concentrations in the bloodstream for up to 36 (treatment at 3.8 mg/kg) or 60 h (treatment at 7.5 mg/kg) post-administration. There was a proportional relationship between the administered ABZ dose and the measured plasma concentrations of both ABZ metabolites. Over a 100% increment on the plasma AUC values for the anthelmintically active ABZSO metabolite was observed at the 7.5 mg/kg compared to the 3.8 mg/kg treatment. The low efficacy patterns (<24%) observed against the GI nematodes investigated indicate a high level of resistance to ABZ given at 3.8 mg/kg an efficacious therapeutic dose rate recommended in some countries. However, the higher and prolonged plasma drug concentration measured after the 7.5 mg/kg treatment resulted in an improved efficacy pattern (estimated by both faecal egg and adult worm counts) against most of the GI nematodes studied compared to that obtained at the lower dose rate. A direct relationship between drug pharmacokinetic behaviour and anthelmintic efficacy against BZD-resistant nematodes in sheep was shown in the current work, although individual variation precluded the observation of statistically significant differences in worm counts.

Surface characterization of reprocessed single-use medical catheters by fractal mass dimension Scandurra, Adriana Gabriela; Arizmendi, Constancio Miguel; Cuadrado, Teresita Raquel; Granados, Dolly Lucía Reprocessing of single-use medical devices is an issue of concern and discussion due to infection risk and operation failure. Cleaning procedures and sterilization processes can produce structural changes and relevant topographical alteration of the biomedical device surfaces which may activate mechanisms able to cause unwanted biological response. Atomic Force Microscopy analysis (AFM) to measure Poly(vinyl chloride) (PVC) catheters surface roughness variation along successive sterilization cycles was applied. In this work, the relation between the number of reprocessing cycles and the fractal mass dimension of reprocessed catheter surface microscopic images is studied.

Influence of hay quality and pasture location on performance of beef cattle grazing oats; Influencia de la calidad del heno suplementario y la localización de la pastura sobre el rendimiento de bovinos de carne a pastoreo sobre avena Arelovich, Hugo Mario; Laborde, Hugo Eduardo; Arzadún, M. J.; Vasquez, Maria Gabriela Heifers grazing oat pasture (OP) at two locations in Argentina, Argerich (ARG) and Pasman (PAS), were subjected to one of three different dietary supplement treatments: (1) control (CON, no supplement), (2) sorghum hay (SH), or (3) alfalfa-grass hay (AGH), all provided ad libitum in individual pens. The variables measured were: dry matter (DM) yield and composition of OP, hay intake, average daily weight gain (ADG), rumen pH and NH3-N, and blood mineral levels. DM availability did not limit OP intake. OP crude protein (CP) content ranged from 11.3 to 13% at ARG, and 10.7 to 13.3% at PAS. OP-minerals varied with location; the mean K/(Ca + Mg) ratios were 5.68 meq (ARG) and 4.82 meq (PAS). Heifers ate more AGH (785 g) than SH (684 g; P = 0.08). Hay consumption was 2.88 times greater at PAS than at ARG (P < 0.05). ADG was larger with SH (558 g) and AGH 594 g than with CON treatment (454 g); the average for ARG animals was 571 g compared to 500 g for PAS animals (P <0.05). Rumen pH was lower at 14:30 h (pH 6.7) than at 10:00 h (pH 7.5; P < 0.05). NH3-N values were higher at 14:30 h (19.59 mg dl-1) than at 10:00 h (4.69 mg dl-1; P < 0.05). Plasma Ca (15.50 mg dl–1) and Mg (2.84 mg dl–1) levels were higher in PAS cattle (P < 0.05). Animal performance improved with hay supplementation, but location affected response intensity.; Se realizaron tres tratamientos con novillas pastoreando verdeos de avena (VA) en dos localidades de Argentina, Argerich (ARG) y Pasman (PAS): (1) Control (CON, sin suplemento), (2) heno de sorgo (HS), y (3) heno de alfalfa y gramíneas (HAG), suplementados ad libitum en corrales individuales. Evaluamos rendimiento de materia seca (MS) y composición en VA; y en los animales consumo del heno, ganancia diaria de peso (GDP), pH y N-NH3 en rumen, y minerales en sangre. La disponibilidad de MS no limitó el consumo de VA; su proteína bruta (PB) osciló entre 11,3 y 13% (ARG), 10,7 y 13.3% (PAS). Los minerales en VA variaron entre localidades, la relación K/(Ca + Mg) promedió 5,68 meq (ARG) y 4,82 meq (PAS). Las novillas consumieron diariamente más HAG (785 g) que HS (684 g; P = 0.08), y 2,88 veces más heno en PAS que en ARG (P < 0,05). En GDP, HS (558 g) y HAG (594 g) superaron al CON (454 g), y la media de ARG (571 g) a PAS (500 g; P < 0,05). En el rumen el pH decreció a las 14:30 h (6,7) vs. 10:00 h (7,5; P < 0,05), y el N-NH3 (mg dl-1) aumentó a las 14:30 h (19,59) vs. 10:00 h (4,69; P < 0,05). Ca (15.50 mg dl–1) y Mg (2.84 mg dl–1) en plasma fue mayor en PAS (P < 0,05). El rendimiento animal mejoró con la suplementación, pero la magnitud de respuesta estuvo afectada por la localidad.

Targeted inhibition of galectin-1 gene expression in tumor cells results in heightened T cell-mediated rejection: a potential mechanism of tumor-immune privilege Rubinstein, Natalia; Alvarez, Mariano; Zwirner, Norberto Walter; Toscano, Marta Alicia; Ilarregui, Juan Martin; Bravo, Alicia; Jose Mordoh; Leonardo Fainboim; Podhajcer, Osvaldo Luis; Rabinovich, Gabriel Adrián Despite the existence of tumor-specific immune cells, most tumors have devised strategies to avoid immune attack. We demonstrate here that galectin-1 (Gal-1), a negative regulator of T cell activation and survival, plays a pivotal role in promoting escape from T cell-dependent immunity, thus conferring immune privilege to tumor cells. Blockade of immunosuppressive Gal-1 in vivo promotes tumor rejection and stimulates the generation of a tumor-specific T cell-mediated response in syngeneic mice, which are then able to resist subsequent challenge with wild-type Gal-1-sufficient tumors. Our data indicate that Gal-1 signaling in activated T cells constitutes an important mechanism of tumor-immune escape and that blockade of this inhibitory signal can allow for and potentiate effective immune responses against tumor cells, with profound implications for cancer immunotherapy

Supplement to the paper “Packed Bed Photocatalytic Reactors . A Packing Structure Model and its Experimental Validation with Computerized Tomography Irazoqui, Horacio Antonio; Isla, Miguel Angel; Brandi, Rodolfo Juan The radiation field in photocatalytic packed beds results from direct energy exchange between the lamp and the catalytic beads, and from mutual exchange between beads that are close to each other. The statistical description of these exchange mechanisms requires of the knowledge of the one-particle and two-particle distribution functions. The detailed physical and mathematical basis of a statistical model of the structure of a bed of spherical-like particles of non-negligible diameter, are presented in this supplement. The proposed model has been cast in terms of one and two-particle distribution functions, based on a widely accepted physical picture of the packing structure. The model reproduces the expected bed structure surrounding arbitrarily chosen particles at different distances from the annulus walls. Elsewhere [9], this theoretical model has been validated against results obtained with tomography experiments.

Vibrational spectra of Cd2As2O7 Baran, Enrique José; Weil, Matthias The infrared and Raman spectra of Cd2As2O7, belonging to the thortveitite structural type, were recorded and are discussed on the basis of a factor group analysis and by comparisons with related compounds.

Nitric oxide, complex I, and the modulation of mitochondrial reactive species in biology and disease Carreras, Maria Cecilia; Franco, María Clara; Peralta, Jorge Guillermo; Poderoso, Juan José Mitochondria are the specialized organelles for energy metabolism but also participate in the production of O2 active species, cell cycle regulation, apoptosis and thermogenesis. Classically, regulation of mitochondrial energy functions was based on the ADP/ATP ratio, which dynamically stimulates the transition between resting and maximal O2 uptake. However, in the last years, NO was identified as a physiologic regulator of electron transfer and ATP synthesis by inhibiting cytochrome oxidase. Additionally, NO stimulates the mitochondrial production of O 2 active species, primarily O2- and H 2O2, and, depending on NO matrix concentration, of ONOO-, which is responsible for the nitrosylation and nitration of mitochondrial components. By this means, alteration in mitochondrial complexes restricts energy output, further increases O2 active species and changes cell signaling for proliferation and apoptosis through redox effects on specific pathways. These mechanisms are prototypically operating in prevalent generalized diseases like sepsis with multiorgan failure or limited neurodegenerative disorders like Parkinson's disease. Complex I appears to be highly susceptible to ONOO- effects and nitration, which defines an acquired group of mitochondrial disorders, in addition to the genetically induced syndromes. Increase of mitochondrial NO may follow over-expression of nNOS, induction and translocation of iNOS, and activation and/or increased content of the newly described mtNOS. Likewise, mtNOS is important in the modulation of O2 uptake and cell signaling, and in mitochondrial pathology, including the effects of aging, dystrophin deficiency, hypoxia, inflammation and cancer.

In vitro effect of gamma-aminobutyric acid on bovine spermatozoa capacitation Ritta, Monica Nora; Bas, Diana Ester; Tartaglione, C. M. Sperm capacitation is defined as the maturational changes that render a sperm competent for fertilization and occurs in the female reproductive tract. Identification of the factor/s that regulate sperm capacitation would allow the understanding of these phenomena. Among these factors, gamma-aminobutyric acid (GABA) has recently become as a putative modulator of sperm function. The aim of this study was to explore the presence of a GABAergic regulation of bovine sperm capacitation as well as the possible intracellular mechanisms involved. GABA was detected in fresh semen by a sensitive radioreceptor assay (spermatozoa, 0.064 +/- 0.003 nmoles/10(6) cells; seminal plasma, 23.21 +/- 1.16 nmoles/ml). Scatchard analysis of [(3)H]-muscimol binding to sperm membranes yielded a linear plot consistent with a single population of binding sites (K(d) = 3.87 nM, B(max) = 417 fmol/mg prot.). [(3)H]-muscimol specific binding to sperm membranes was significantly inhibited by the GABA A receptor (GABA A-R) antagonist bicuculline and by the agonists muscimol and isoguvacine. Addition of GABA to the incubation medium resulted in a concentration-dependent increase in the percentage of capacitated spermatozoa (chlortetracycline assay). We observed a significant increment on intracellular calcium and cyclic 3',5' adenosine monophosphate (cAMP) concentrations induced by GABA, being the cation influx abolished when the cell suspensions were coincubated with the antagonists bicuculline or picrotoxin. It is concluded that GABA induces sperm capacitation through an intracellular mechanism dependent on calcium influx and cAMP accumulation mediated by a specific GABA A-R.

Anterior hypothalamic β-adrenergic activity in the maintenance of hypertension in aortic coarctated rats Höcht, Christian; Opezzo, Javier A. W.; Taira, Carlos Alberto The aim of this work was to demonstrate an alteration of the anterior hypothalamic catecholaminergic system in aortic coarctated (ACo) rats by the perfusion of β-adrenergic antagonist and the microinfusion of β-adrenergic agonist. Wistar urethane-chloralose anesthetized rats were used. The carotid artery was cannulated for blood pressure recording and changes in blood pressure were measured. A concentric microdialysis probe was inserted in the anterior hypothalamus. Metoprolol (a β1- adrenoceptor antagonist) perfusion (6μgml-1) reduced the mean arterial pressure (MAP) in the ACo rats but not in sham operated (SO) animals. The anterior hypothalamic infusion of non-specific β-adrenergic agonist isoproterenol induced a dose-dependent decrease of blood pressure in both experimental groups, but the depressor response was significantly lower in ACo rats. The pretreatment with atenolol, a selective β1- adrenoceptor antagonist, increased the depressor effect of isoproterenol in ACo rats, but not in SO rats. On the other hand, the hypotensive action of isoproterenol was significantly diminished after the administration of non-specific β-adrenoceptor antagonist propranolol in SO and ACo rats. The anterior hypothalamic infusion of clenbuterol, a selective β 2-adrenergic agonist, induced a dose-dependent decrease of blood pressure in both experimental groups. The depressor response to clenbuterol (1nmol) was significantly lower in ACo rats than in SO rats. In summary, this study provides the evidence that there is a β1-adrenergic compromise in anaesthetized ACo rats and this compromise may be involved in the maintenance of hypertension. On the other hand, this study also suggests the existence of pressor β1-adrenoceptors in the anterior hypothalamic area of ACo rats but not in SO rats. We also found a diminished depressor β2-adrenergic activity in ACo rats.

Early juvenile pterosaurs (Pterodactyloidea: Pterodaustro guinazui) from the Lower Cretaceous of central Argentina Codorniú Dominguez, Laura Susana; Chiappe, Luis We report on two juvenile specimens of Pterodaustro guinazui, a medium-sized, filter-feeding pterodactyloid pterosaur from the Lower Cretaceous (Albian) lacustrine deposits of the Lagarcito Formation of central Argentina (Sierra de Las Quijadas, San Luis Province). Both specimens lack the skull, but one is otherwise nearly complete and articulated, and the other is more fragmentary. Their small size (~300 mm of wingspan), the lack of fusion of several postcranial bones, the minimal epiphyseal ossification, and the porous appearance of the periosteal surfaces indicate the specimens died at a very early stage of postnatal development. The presence of derived characters unique, within Pterodactyloidea, to P. guinazui (e.g., caudal vertebrae exceeding 16 elements) supports the proposed specific identification of the specimens. The new material provides anatomical information previously unknown for P. guinazui and sheds light on allometric transformations during the growth of this pterosaur. Comparisons with more mature and much larger individuals support two major allometric trends: (i) the negative allometric growth of the proximal portion of the forelimb, and (ii) the positive allometric growth of the metacarpal IV.; Nous soumettons un article sur deux spécimens juvéniles de Pterodaustro guinazui, un ptérosaurien ptérodactyloidé, de taille moyenne et qui se nourrit par filtrage, dans les dépôts lacustres de la Formation de Lagarcito (Crétacé inférieur – Albien) du centre de l'Argentine (Sierra de Las Quijadas, province de San Luis). Aucun des deux spécimens n'a de crâne mais l'un des deux est presque complet et articulé alors que l'autre est plus fragmenté. Leur petite taille (envergure ~ 300 mm), le manque de fusion de plusieurs os postcrâniens, l'ossification épiphysaire minimale et l'apparence poreuse des surfaces du périoste indiquent que les spécimens sont morts à un stage très précoce de développement postnatal. La présence de caractères dérivés, uniques à Pterodaustro guinazui chez les ptérodactylidés, (p. ex. des vertèbres caudales à plus de 16 éléments) supporte l'identification spécifique proposée des spécimens. Le nouveau matériel fournit de l'information anatomique auparavant inconnue pour Pterodaustro guinazui et nous renseigne sur les transformations allométriques au cours de la croissance de ce ptérosaurien. Des comparaisons avec des individus plus adultes et beaucoup plus grands supportent deux tendances allométriques majeures : (1) la croissance allométrique négative de la portion proximale du membre antérieur et (2) la croissance allométrique positive du 4e métacarpien.