CAPTURA. Repositorio Academico de la Universidad de Chile
(5.176 recursos)
Captura almacena y conserva la producción de conocimiento generado por docentes e investigadores de la Universidad de Chile, y la hace visible desde los portales académicos internacionales.
Mostrando recursos 1 - 20 de 626
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Phase II multi-institutional randomized trial of docetaxel plus cisplatin with or without fluorouracil in patients with untreated, advanced gastric, or gastroesophageal adenocarcinoma - Ajani, Jaffer A.; Fodor, Miguel; Tjulandin, Sergei; Moiseyenko, Vladimir M.; Chao, Yee; Cabral, Sebastiao; Majlis, Alejandro; Assadourian, Sylvie; Van Cutsem, Eric
Purpose The purpose of this study was to define the contribution of docetaxel to combination chemotherapy in the outcome of patients with advanced gastric or gastroesophageal adenocarcinoma. We compared the overall response rate (ORR) and safety of docetaxel plus cisplatin (DC) with DC plus fluorouracil (DCF) to select either DC or DCF as the experimental treatment in the ensuing phase III part of trial V-325.
Patients and Methods In this phase II randomized study, untreated patients with confirmed advanced gastric or gastroesophageal adenocarcinoma received either DCF (docetaxel 75 mg/m(2), cisplatin 75 mg/m(2) on day 1, and fluorouracil 750 mg/m(2)/d as continuous...
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Cell type-specific recruitment of Drosophila Lin-7 to distinct MAGUK-based protein complexes defines novel roles for Sdt and Dlg-S97 - Bachmann, André; Timmer, Marco; Sierralta, Jimena; Pietrini, Grazia; Gundelfinger, Eckart D.; Knust, Elisabeth; Thomas, Ulrich
Stardust (Sdt) and Discs-Large (Dig) are membrane-associated guanylate kinases (MAGUKs) involved in the organization of supramolecular protein complexes at distinct epithelial membrane compartments in Drosophila. Loss of either Sdt or Dig affects epithelial development with severe effects on apico-basal polarity. Moreover, Dig is required for the structural and functional integrity of synaptic junctions. Recent biochemical and cell culture studies have revealed that various mammalian MAGUKs can interact with mLin-7/Veli/MALS, a small PDZ-domain protein. To substantiate these findings for their in vivo significance with regard to Sdt- and Dlg-based protein complexes, we analyzed the subcellular distribution of Drosophila Lin-7 (DLin-7) and...
3.
Identification of a gene cluster for the formation of extracellular polysaccharide precursors in the chemolithoautotroph Acidithiobacillus ferrooxidans - Barreto, Marlen; Jedlicki C., Eugenia María; Holmes, David S.
A cluster of five genes, proposed to be involved in the formation of extracellular polysaccharide (EPS) precursors via the Leloir pathway, have been identified in the acidophilic autotroph Acidithiobacillus ferrooxidans. The order of the genes is luxA-galE-galK-pgm-galM, encoding a LuxA-like protein, UDP-glucose 4-epimerase, galactokinase, phosphoglucomutase, and galactose mutarotase, respectively. The gal cluster forms a single transcriptional unit and is therefore an operon. Two other putative genes of the Leloir pathway, galU, potentially encoding UDP-glucose pyrophosphorylase, and a gene designated galT-like, which may encode a gallactose-1-phosphate uridylyltransferase-like activity, were found unlinked in the genome. Using semiquantitative reverse transcription-PCR, the genes of...
4.
Signal transduction and gene expression regulated by calcium release from internal stores in excitable cells - Carrasco, María Angélica; Jaimovich P., Enrique; Kemmerling, Ulrike; Hidalgo, Cecilia
Calcium regulation of several transcription factors involves different calcium-dependent signaling cascades and engages cytoplasmic as well as nuclear calcium signals. The study of the specific sources of calcium signals involved in regulation of gene expression in skeletal muscle has been addressed only recently. In this tissue, most cytoplasmic and nuclear calcium signals originate from calcium release from internal stores, mediated either by ryanodine receptor (RyR) or IN receptor (IP3R) channels. The latter are located both in the sarcoplasmic reticulum (SR) and in the nuclear membrane, and their activation results in long-lasting nuclear calcium increase. The calcium signals mediated by RyR...
5.
Behavioral effects of manganese injected in the rat substantia nigra are potentiated by dicumarol, a DT-diaphorase inhibitor - Díaz Véliz, Gabriela; Mora, Sergio; Gómez, Patricia; Dossi, María Teresa; Montiel, Juan; Arriagada, Christian; Aboitiz, Francisco; Segura Aguilar, Juan
The purpose of this study was to evaluate the contribution of DT-diaphorase inhibition to in vivo neurodegenerative effects of dopamine (DA) oxidation to the corresponding o-quinones. The neurotoxicity to nigrostriatal DA neurons was induced by injection of manganese pyrophosphate (Mn3+) complex as a prooxidizing agent alone or together with the DT-diaphorase inhibitor dicumarol into the right rat substantia nigra. The behavioral effects were compared with those induced after selective lesions of dopaminergic neurons with 6-hydroxydopamine (6-OHDA). Intranigral injection of Mn3+ and Mn3+ plus dicumarol produced significant impairment in motor behavior compared with control animals. However, the effect seen in the...
6.
Nuclear inositol 1,4,5-trisphosphate receptors regulate local Ca2+ transients and modulate cAMP response element binding protein phosphorylation - Cárdenas, César; Liberona, José Luis; Molgó, Jordi; Colasante, Cesare; Mignery, Gregory; Jaimovich P., Enrique
Several lines of evidence indicate that increases in nuclear Ca2+ have specific biological effects that differ from those of cytosolic Ca2+, suggesting that they occur independently. The mechanisms involved in controlling nuclear Ca2+ signaling are both controversial and still poorly understood. Using hypotonic shock combined with mechanical disruption, we obtained and characterized a fraction of purified nuclei from cultured rat skeletal myotubes. Both immunoblot studies and radiolabeled inositol 1,4,5-trisphosphate [IP3] binding revealed an important concentration Of IP3 receptors in the nuclear fraction. Immunofluorescence and immunoelectron microscopy studies localized type-1 and type-3 IP3 receptors in the nucleus with type-1 receptors preferentially...
7.
Cintigrama renal DMSA en niños con primera pielonefritis aguda: correlación con exámenes de laboratorio, ecografía y la presencia de reflujo vésico ureteral - Donoso R., Gilda; Lobo S., Gabriel; Arnello V., Francisca; Arteaga V., María Paz; Hevia J., Pilar; Rosati M., Pía; Lagos R., Elizabeth; Wolff, Carlos; Pérez R., Andrés; Jiménez J., César
Background: Tc99m DMSA (dimercaptosuccinic acid) scintigraphy has a high sensitivity for the detection of cortical kidney damage. Aim: To evaluate the Tc99m DMSA renal scintigraphy in children with a first episode of acute pyelonephritis and its association with laboratory parameters, kidney ultrasound and vesicoureteral reflux. Patients and methods: We studied 143 children (age range 8 days, 12 Years, 66% female) hospitalized with the clinical diagnosis of acute pyelonephritis (first episode) with a positive urine culture and a renal scintigraphy performed within seven days of diagnosis. DMSA was considered the gold standard for the detection of cortical lesions. Its results were...
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A review on electron microscopy and neurotransmitter systems - Torrealba, Fernando; Carrasco, María Angélica
The purpose of this article is to review the contributions of transmission electron microscopy studies to the understanding of brain circuits and neurotransmitter systems. Our views on the microstructure of connections between neurons have gradually changed, and now we recognize that the classical mental image we had on a chemical synapse is no longer applicable to every neuronal connection. We highlight studies that converge to point out that, while the most prevalent fast transmitters in the brain, glutamate and GABA, are stored in small, clear synaptic vesicles (SSV) and released at synapses, neuropeptides are exclusively stored in large dense core...
9.
Molecular diversity among domestic guinea-pigs (Cavia porcellus) and their close phylogenetic relationship with the Andean wild species Cavia tschudii - Spotorno, Angel; Valladares, John P.; Marín, Juan C.; Zeballos, Horacio
To investigate the origin and diversity of domestic guinea-pigs Cavia porcellus (Linnaeus, 1758; Rodentia, Caviidae), we sequenced the mitochondrial cytochrome b gene of 12 domestic and 10 wild specimens from six species, including the two presumed as ancestral to the domestic one: Cavia tschudii and Cavia aperea. All maximum parsimony and maximum likelihood analyses grouped C. porcellus with C. tschudii (mean K2P distance = 3.2%); best trees had 609 steps (CI = 0.796; Bremer support Index (SI) = 28), and a -Ln = 4419.52, with 100% and 97% bootstrap support respectively. This clade, supported by three substitutions and 96% bootstrap,...
10.
Time in physics and biology - Günther, Bruno; Morgado, Enrique
In contrast with classical physics, particularly with Sir Isaac Newton, where time is a continuous function, generally valid, eternally and evenly flowing as an absolute time dimension, in the biological sciences, time is in essence of cyclical nature (physiological periodicities), where future passes to past through an infinitely thin boundary, the present. In addition, the duration of the present (DP) leads to the so-called 'granulation of time' in living beings, so that by the fusion of two successive pictures of the world, which are not entirely similar, they attain the perception of 'movement,' both in the real world as well...
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Possible link of different slow calcium signals generated by membrane potential and hormones to differential gene expression in cultured muscle cells - Jaimovich P., Enrique; Espinosa, Alejandra
The study of fluorescent calcium signals from cultured rat myotubes has provided interesting results in the past few years. Both K+ depolarization and tetanic electrical stimulation were shown to produce slow Ca2+ signals, unrelated to contraction and associated to regulation of gene expression in cultured rat myotubes. We studied the effect of IGF-I, insulin and testosterone on intracellular Ca2+ in cultured muscle cells. Insulin produced a fast (<1 s) and transient [Ca2+] increase lasting less than 10 s. IGF-I induced a transient [Ca2+] increase, reaching a fluorescence peak 6 s after stimulus, to return to basal values after 60 s....
12.
Neutral endopeptidase and angiotensin I converting enzyme insertion/deletion gene polymorphism in humans - Jalil, Jorge E.; Ocaranza, María Paz; Oliveri, C.; Córdova, S.; Godoy, I.; Chamorro, G.; Braun, S.; Fardella, C.; Michel, J. B.; Lavander, S.
Neutral endopeptidase (NEP) hydrolyses angiotensins (Ang) I and II and generates angiotensin-(1-7) [Ang-(17)]. In humans, the insertion/deletion (I/D) angiotensin- I converting enzyme ( ACE) gene polymorphism determined plasma ACE levels by 40%. In rats, a similar polymorphism determines ACE levels which are inversely associated to NEP activity. The objective of this study is to evaluate the relationship between ACE expression and plasma NEP activity in normotensive subjects and in hypertensive patients. In total, 58 consecutive patients with hypertension, evaluated in our Hypertension Clinic, were compared according to their ACE I/D genotypes with 54 control subjects in terms of both plasma...
13.
The battering of informed consent - Kottow Lang, Miguel
Autonomy has been hailed as the foremost principle of bioethics, and yet patients' decisions and research subjects' voluntary participation are being subjected to frequent restrictions. It has been argued that patient care is best served by a limited form of paternalism because the doctor is better qualified to take critical decisions than the patient, who is distracted by illness. The revival of paternalism is unwarranted on two grounds: firstly, because prejudging that the sick are not fully autonomous is a biased and unsubstantial view; secondly, because the technical knowledge of healthcare professionals does not include the ethical qualifications and prerogative...
14.
Isobolographic analysis of the antinociceptive interactions of clonidine with nonsteroidal anti-inflammatory drugs - Miranda, Hugo; Pinardi, Gianni
The present study was undertaken to characterize the interactions between nonsteroidal anti-inflammatory drugs and the alpha(2)-adrenoceptor agonist clonidine in an acute nociceptive test. The writhing test was selected as a model of acute visceral pain. Isobolograms were constructed to assess the interactions of clonidine and each nonsteroidal anti-inflammatory drugs, when coadministered intraperitoneally and intrathecally (i.t.). The simultaneous intraperitoneal administration of fixed ratios of ED50 fractions of all nonsteroidal anti-inflammatory drugs (naproxen, piroxicam, paracetamol, dipyrone or metamizol and nimesulide) combined with clonidine resulted in synergistic interactions. The same combinations administered intrathecally were additive. The synergistic interactions between systemic nonsteroidal anti-inflammatory drugs...
15.
Receptors and Ca2+ signals in adult skeletal muscle satellite cells in situ - Molgó, Jordi; Colasante, Cesare; Adams, Dany S.; Jaimovich P., Enrique
In this short article we review muscle satellite cell characteristics and our studies in adult rodent muscle satellite cells in situ. Using confocal laser scanning microscopy and immunocytochemistry, a high level of IP3 receptor (IP3R) immunostaining was detected in satellite cells. These cells were identified by their peripheral position, their size, the shape of their nucleus, the paucity of the apparent cytoplasm, and the immunostaining with specific molecular markers such as alpha-actinin, the neural cell adhesion molecule (N-CAM) and desmin. High extracellular K+ (60 mM) induced long-lasting Ca2+ signals in satellite cells in situ. We suggest that electrical activity stimulates...
16.
Changes of enzyme activity in lipid signaling pathways related to substrate reordering - Salinas, Dino; Fuente, Milton de la; Reyes, Juan
The static fluid mosaic model of biological membranes has been progressively complemented by a dynamic membrane model that includes phospholipid reordering in domains that are proposed to extend from nanometers to microns. Kinetic models for lipolytic enzymes have only been developed for homogeneous lipid phases. In this work, we develop a generalization of the well-known surface dilution kinetic theory to cases where, in a same lipid phase, both domain and nondomain phases coexist. Our model also allows understanding the changes in enzymatic activity due to a decrease of free substrate concentration when domains are induced by peptides. This lipid reordering...
17.
Medicina evolucionario: una ciencia básica emergente - Spotorno, Angel
Evolutionary Medicine is an emergent basic science that offers new and varied perspectives to the comprehension of human health. The application of classic evolutionary theories (descent with modification., and natural selection) to the human organism, to its pathogens, and their mutual co-evolution, provides new explanations about why we get sick, how we can prevent this, and how we can heal. Medicine has focused mainly on the proximate or immediate causes of diseases and the treatment of symptoms, and very little on its evolutionary or mediate causes. For instance, the present human genome and phenotypes are essentially paleolithic ones: they are...
18.
Linfoma intravascular tratado con anticuerpos monoclonales anti CD20: descripción de un caso clínico - Alfaro L., Jorge; Espinoza N., Arturo; Manríquez A., María; Moyano, Leonor; González G., Néstor; Larrondo L., Milton; Figueroa M., Gastón
We report a 78 year old male with prostatism, that was subjected to a prostate biopsy. The pathological study showed a microvascular lymphocytic infiltration. Four months later, the patients presented with reduced alertness, cough, dyspnea, fever and elevation of lactic dehydrogenase and erythrocyte sedimentation rate. Chest and abdominal CAT scans, bone marrow aspirate, protein electrophoresis and prostate specific antigen were normal. A re-evaluation of prostate biopsy showed an intravascular lymphoid infiltration, positive for CD45 and CD20, compatible with the diagnosis of intravascular lymphoma. Chemotherapy was started, but it was not tolerated by the patient and the response was partial. Therefore,...
19.
Structure of the regulatory subunit of CK2 in the presence of a p21(WAF1) peptide demonstrates flexibility of the acidic loop - Bertrand, Loic; Sayed, Muhammed F. R.; Pei, Xue-Yuan; Parisini, Emilio; Dhanaraj, Venugopal; Bolaños García, Víctor M.; Allende, Jorge E.; Blundell, Tom L.
A truncated form of the regulatory subunit of the protein kinase CK2beta ( residues 1 - 178) has been crystallized in the presence of a fragment of the cyclin-dependent kinase inhibitor p21(WAF1) ( residues 46 - 65) and the structure solved at 2.9 Angstrom resolution by molecular replacement. The core of the CK2beta dimer shows a high structural similarity with that identified in previous structural analyses of the dimer and the holoenzyme. However, the electron density corresponding to the substrate-binding acidic loop ( residues 55 - 64) indicates two conformations that differ from that of the holoenzyme structure [ Niefind...
20.
Structure of the regulatory subunit of CK2 in the presence of a p21(WAF1) peptide demonstrates flexibility of the acidic loop - Bertrand, Loic; Sayed, Muhammed F. R.; Pei, Xue-Yuan; Parisini, Emilio; Dhanaraj, Venugopal; Bolaños García, Víctor M.; Allende, Jorge E.; Blundell, Tom L.
A truncated form of the regulatory subunit of the protein kinase CK2beta ( residues 1 - 178) has been crystallized in the presence of a fragment of the cyclin-dependent kinase inhibitor p21(WAF1) ( residues 46 - 65) and the structure solved at 2.9 Angstrom resolution by molecular replacement. The core of the CK2beta dimer shows a high structural similarity with that identified in previous structural analyses of the dimer and the holoenzyme. However, the electron density corresponding to the substrate-binding acidic loop ( residues 55 - 64) indicates two conformations that differ from that of the holoenzyme structure [ Niefind...
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