Publications by authors named "Estevez J"

Lignified cell walls are widely considered to be key innovations in the evolution of terrestrial plants from aquatic ancestors some 475 million years ago. Lignins, complex aromatic heteropolymers, stiffen and fortify secondary cell walls within xylem tissues, creating a dense matrix that binds cellulose microfibrils and crosslinks other wall components, thereby preventing the collapse of conductive vessels, lending biomechanical support to stems, and allowing plants to adopt an erect-growth habit in air. Although "lignin-like" compounds have been identified in primitive green algae, the presence of true lignins in nonvascular organisms, such as aquatic algae, has not been confirmed.

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The title compound, C(24)H(27)NO(9), is one of the epimers of the Henry reaction of 3-O-benzyl-6-O-benzoyl-2-O-isopropyl-idene-a-d-glucofuran-5-one with nitro-methane. The conformation of the five membered rings is as expected from the precursor compound and the mol-ecule is folded with a dihedral angle of 51.4 (2)° between the aromatic rings.

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In this article, we aimed to describe the changes related to mating season in red deer, especially those related to antler growth, body condition score, testosterone and cortisol. Antler growth was studied in 17 Iberian red deer males, including body weight, antler length, biometric measures and testosterone and cortisol determination during 15 months. Body weight, body condition score, thoracic perimeter (TP), neck perimeter (NL) and testicular diameter (TD) showed the highest values immediately before mating season (autumn), decreased during it and remained constant at winter.

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We studied some biochemical, toxic and immunological characteristics of the venoms of Bothrops atrox, Bothrops brazili and Lachesis muta, Viperidae responsible for most of the bites of venomous snakes in French Guiana. Chromatographic (HPLC) and electrophoretical profiles (SDS-PAGE), lethal, hemorrhagic, defibrinogenating, coagulant, thrombin like, proteolytic, fibrino(geno)lytic and phospholipase activities were studied. In addition, the neutralization of some toxic activities conferred by four antivenins was compared.

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Background: Viral load in pediatric patients with HIV infections can help to make therapeutic decisions to modify the evolution of the disease.

Aim: To evaluate viral load in positive HIV children with antiretroviral treatment.

Material And Methods: Viral load was measured every six months during three years in fifty pediatric patients chosen randomly in aged 1 to 12 years, using the Test Monitor HIV-1 AMPLICOR, version 1.

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A comprehensive analysis of the carbohydrate-containing macromolecules from the coencocytic green seaweed Codium fragile and their arrangement in the cell wall was carried out. Cell walls in this seaweed are highly complex structures composed of 31% (w/w) of linear (1-->4)-beta-D-mannans, 9% (w/w) of pyruvylated arabinogalactan sulfates (pAGS), and low amounts of hydroxyproline rich-glycoprotein epitopes (HRGP). In situ chemical imaging by synchrotron radiation Fourier transform infrared (SR-FTIR) microspectroscopy and by immunolabeling using antibodies against specific cell wall carbohydrate epitopes revealed that beta-d-mannans and pAGS are placed in the middle part of the cell wall, whereas HRGP epitopes (arabinogalactan proteins (AGPs) and extensins) are located on the wall boundaries, especially in the utricle apical zone.

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Cell wall changes in vegetative and suffultory cells (SCs) and in oogonial structures from Oedogonium bharuchae N. D. Kamat f.

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Maternal phenotypic characteristics can influence key life history variables of their offspring through maternal effects. In this study, we examined how body size constraints on maternal weight in yearling and subadult compared to adult hinds (age class effects) affected prenatal (calf birth weight, calf to hind weight ratio) and postnatal (milk) provisioning of Iberian red deer calves. Age correlated with all prenatal and postnatal investment traits except calf gains, although correlations were weaker than those with maternal weight.

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Sulfated polysaccharides were localized in the cuticle, cortex and medulla of the gametophyte thallus, being more concentrated in the intercellular matrix than in the cell walls. During the water extraction sequence, a small percentage of galactan sulfates (5.1% of dry seaweed) with average low Mr (6-11.

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Bothrops cotiara is a venomous snake sporadically found in the province of Misiones in Argentina, South of Brazil and Paraguay. Data on the clinics of the envenomation produced by its bite and on its venom are scarce. There is no information on the neutralizing capacity of the antivenoms available.

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The aim of this study was to determine the prevalence of hepatitis B virus (HBV) infection in the Japreira indigenous community, Venezuela, and its relationship to age and gender. An intentional, non-probabilistic sample of 149 individuals was selected from a total of 300. All samples were studied for the presence of total HBV antibodies (total anti-HBc), and the positive samples were tested for HBV surface and "e" antigens (HBsAg, HBeAg).

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An eight-year old boy from Posadas (27 masculine 23'S, 55 masculine 54'W) was diagnosed with visceral leishmaniasis (VL) during 2006. Lutzomyia longipalpis was discovered in the backyard of his house, while the spread of canine visceral leishmaniasis was confirmed in Posadas. This is the southernmost report of a VL transmission focus and the first in Argentina.

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Clinical and experimental evidence support a relationship between susceptibility to chronic pain and a subjacent depression. Nevertheless, it's not clear if the currently available clinical evaluation instruments for depression allow for linking both disorders. Thus, we evaluated a Zung's autoscale for depression and its different categories: affective, physiological, motor and psychological, as possible predictors of sensorial and autonomic alterations and vulnerability to clinical chronic pain.

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The title compound {systematic name: (2S,3R)-ethyl 3-[(3aS,4R,6S,6aS)-6-tert-butyl-dimethyl-silyl-oxy-2,2-dimethyl-per-hydro-furo[3,4-d][1,3]dioxol-4-yl]-2-nitro-3-[(S)-tetra-hydro-2H-pyran-2-yl-oxy]propanoate}, C(23)H(41)NO(10)Si, is the product of the Henry reaction of 1-O-tert-butyl-dimethyl-silyl-2,3-O-isopropyl-idene-α-d-lyxo-penta-dialdo-1,4-furan-ose with ethyl nitro-acetate and the subsequent protection of its C-5 hydr-oxy group as tetra-hydro-pyranyl, in order to avoid the retro-Henry reaction. The tetra-hydro-pyranyl group adopts a chair conformation. The absolute configuration, assumed from the synthesis, was confirmed from the diffraction data.

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Objective: To find out the opinion of Primary Health Care (PHC) professionals on the impact of the Preventive Activities and Health Promotion Program (PAPPS).

Design: Descriptive qualitative-quantitative study. In a first phase the SWOT technique was used.

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We describe the first, to our knowledge, cases of han-tavirus pulmonary syndrome in northeastern Argentina and eastern Paraguay. Andes and Juquitiba (JUQ) viruses were characterized. JUQV was also confirmed in 5 Oligoryzomys nigripes reservoir species from Misiones.

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Codium fragile and Codium vermilara biosynthesize water-soluble sulfated arabinans and galactans (and/or sulfated arabinogalactans), alpha(1-->4)-D-glucans and beta(1-->4)-D-mannans. The former polysaccharides are composed by 3-linked beta-D-galactopyranose and beta-L-arabinopyranose residues, they are highly sulfated and substituted with pyruvic acid ketals. For both seaweeds, they have the same main structural units, but in different percentages.

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Antler is a good model to study bone biology both because it is accessible and because it grows and is shed every year. Previous studies have shown that chemical composition changes as the antler is grown, implying constraints in mineral availability and the physiological effort made to grow it. This study aimed at examining antler mechanical properties to assess whether they reflect physiological effort and whether they are associated with precise mineral bone composition rather than just ash content, which is usually the main factor affecting mechanical properties.

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Hepatic abscess due to perforation of the gastrointestinal tract caused by ingested foreign bodies is uncommon. Pre-operative diagnosis is difficult as patients are often unaware of the foreign body ingestion and symptoms and imagiology are usually non-specific. The authors report a case of 62-year-old woman who was admitted with fever and abdominal pain.

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Studies done with human and animals have shown that the diminished vitamin A intake can produce anemia, but the ethiopathogenic mechanism hasn't been known due to the few studies about the complex interactions between micronutrients deficiencies, immune system and cytokine productions. The objective of the present study was to analyze the serum concentration of IFN-gamma and IL-10 in anemic and non anemic children according to vitamin A nutritional status. A descriptive study of 53 euthrophic children, without infectious diseases (45-77 month old; 29 girls, 24 boys), living in a slum in Maracaibo-Venezuela.

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A novel promising strategy for the transformation of nitrosugars into branched pyrrolidines, based on double Henry reaction with formaldehyde followed by reductive ring closure, allowed the first enantiospecific synthesis of a 4-C-hydroxymethyl branched derivative of the well-known glycosidase inhibitor 1,4-dideoxy-1,4-imino-pentanol. This strategy also afforded a new route to some other interesting derivatives, such as N-hydroxy, N-propyloxy, and imino derivatives, a new kind of compounds with promising biological properties. [reaction: see text].

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In a previous study, antler bone chemical composition was found to differ between base and tip. If such variation is in part due to the physiological effort made to grow the antler, composition trends should differ between antlers from deer population differing in mineral or food availability, or body reserves. To assess this, we examined cortical thickness and bone composition along the antler shaft, and compared trends between antlers from two populations: captive, well-fed, health-managed deer (n=15), and free-ranging deer with lower food quality and no health treatment (n=10).

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Genes encoding synthetic hydroxyproline-rich peptides with repetitive (Ser-Pro) units linked to an extensin signal sequence and a tetracysteine (TC) sequence were expressed transiently in tobacco, and transiently and stably in Arabidopsis under control of a strong constitutive promoter Expression of these peptides could be visualized in live cells by confocal microscopy following labeling with FlAsH- or ReAsH-EDT2 reagents.

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Different dental procedures in children undergoing treatment can induce changes in blood pressure. These changes will be minimized if psychological treatment is applied prior to any procedure. The objective of this study was to determine changes in blood pressure (systolic-diastolic) in children undergoing psychological treatment before dental procedures.

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