Tema y variaciones de literatura : cuento mexicano del siglo XX. Número 22 (semestre I, 2004)-

1 archivo PDF ; 39.63 Megabytes (520 páginas). TyvlncEn los artículos de este número se reflexiona sobre la obra de importantes cuentistas mexicanos, que dejaron una huella imborrable en la Literatura Mexicana del siglo pasado, como Martin LuisGuzmán, Juan José Arreola, Juan Rulfo, José Revueltas, Juan Vicente Mela, Inés Arredondo, Rosario Castellanos, Francisco Rojas Gonzá lez, Alfonso Reyes, Franci sco Tario, Jorge Ibargüengoitia y Andrés Henestrosa

CdTe Quantum Dot/Dye Hybrid System as Photosensitizer for Photodynamic Therapy

We have studied the photodynamic properties of novel CdTe quantum dots—methylene blue hybrid photosensitizer. Absorption spectroscopy, photoluminescence spectroscopy, and fluorescence lifetime imaging of this system reveal efficient charge transfer between nanocrystals and the methylene blue dye. Near-infrared photoluminescence measurements provide evidence for an increased efficiency of singlet oxygen production by the methylene blue dye. In vitro studies on the growth of HepG2 and HeLa cancerous cells were also performed, they point toward an improvement in the cell kill efficiency for the methylene blue-semiconductor nanocrystals hybrid system

Adaptación de los recursos hídricos al cambio climático: aplicación de modelos hidrológicos al caso de la cuenca del río Babahoyo-Ecuador

La presente tesis doctoral es una contribución metodológica para la incorporación de criterios de cambio climático, en la planificación integral de los recursos hídricos de cuencas hidrográficas, basada en la comparación del cambio de volumen de agua, en los componentes del balance hídrico (BH) entre el periodo base (1986-2005) y los escenarios del IPCC (RCP2.6, RCP4.5, RCP6.0 y RCP8.5) para el periodo (2081-2100), donde la variable cambiante es la temperatura media, que incrementa en 1,00oC, 1,85oC, 2,25oC, y 3,70oC, respectivamente.Sobre la metodología, la complejidad radica en la recopilación, validación y estructuración de información base para hacer correr de los modelos hidrológicos, y los mapas de los componentes del BH e índice de aridez (IDA). La investigación permitió la implementación del desarrollo de una metodología, que probó ser funcional y adecuada para su replicación en otras cuencas hidrográficas de Ecuador, con la flexibilidad de ser perfectible, debido a su funcionalidad como módulo abierto y escalable.Los resultados obtenidos de los componentes del BH para el periodo base y futuros para los diferentes escenarios de cambio climático de trayectoria de concentración representativa (RCP), fueron producto del modelamiento hidrológico con la herramienta ArcSWAT sobre la plataforma de sistemas de información geográfica (SIG). Con el módulo interno de programación orientada a objetos del SIG, fueron elaborados de forma semiautomática, los mapas del balance hídrico (BH), como base para la construcción de índice de aridez (IDA).El IDA permite cuantificar y cualificar zonas climáticas, si bien no es específicamente un índice de cambio climático (modelos de clima para atmósfera), el IDA permite la comparación entre resultados del BH (base y proyección), enmarcado en los escenarios RCP.La presente investigación es una aportación en la contribución metodológica en Ecuador, para la incorporación de criterios de cambio climático en la formulación y actualización de planes de gestión integrada de los recursos hídricos, que permitiría a las autoridades, contar con información en la toma de decisiones a corto, mediano y largo plazo, para garantizar el uso y aprovechamiento del agua, mediante la mitigación de impactos, control de exposición y reducción de vulnerabilidad de los recursos hídricos, que por efecto del cambio climático, son susceptibles de reducción volumétrica del agua útil en la cuenca hidrográfica.<br /

ABI3 ectopic expression reduces in vitro and in vivo cell growth properties while inducing senescence

<p>Abstract</p> <p>Background</p> <p>Mounting evidence has indicated that <it>ABI3 </it>(ABI family member 3) function as a tumor suppressor gene, although the molecular mechanism by which ABI3 acts remains largely unknown.</p> <p>Methods</p> <p>The present study investigated <it>ABI3 </it>expression in a large panel of benign and malignant thyroid tumors and explored a correlation between the expression of ABI3 and its potential partner ABI3-binding protein (ABI3BP). We next explored the biological effects of <it>ABI3 </it>ectopic expression in thyroid and colon carcinoma cell lines, in which its expression was reduced or absent.</p> <p>Results</p> <p>We not only observed that <it>ABI3 </it>expression is reduced or lost in most carcinomas but also that there is a positive correlation between <it>ABI3 </it>and <it>ABI3BP </it>expression. Ectopic expression of <it>ABI3 </it>was sufficient to lead to a lower transforming activity, reduced tumor <it>in vitro </it>growth properties, suppressed <it>in vitro </it>anchorage-independent growth and <it>in vivo </it>tumor formation while, cellular senescence increased. These responses were accompanied by the up-regulation of the cell cycle inhibitor <it>p21 </it>^WAF1and reduced ERK phosphorylation and <it>E2F1 </it>expression.</p> <p>Conclusions</p> <p>Our result links <it>ABI3 </it>to the pathogenesis and progression of some cancers and suggests that ABI3 or its pathway might have interest as therapeutic target. These results also suggest that the pathways through which <it>ABI3 </it>works should be further characterized.</p

Ring-Like Distribution of Constitutive Heterochromatin in Bovine Senescent Cells

Background: Cells that reach ‘‘Hayflick limit’ ’ of proliferation, known as senescent cells, possess a particular type of nuclear architecture. Human senescent cells are characterized by the presence of highly condensed senescent associated heterochromatin foci (SAHF) that can be detected both by immunostaining for histone H3 three-methylated at lysine 9 (H3K9me3) and by DAPI counterstaining. Methods: We have studied nuclear architecture in bovine senescent cells using a combination of immunofluorescence and 3D fluorescent in-situ hybridization (FISH). Results: Analysis of heterochromatin distribution in bovine senescent cells using fluorescent in situ hybridization for pericentric chromosomal regions, immunostaining of H3K9me3, centromeric proteins CENP A/B and DNA methylation showed a lower level of heterochromatin condensation as compared to young cells. No SAHF foci were observed. Instead, we observed fibrous ring-like or ribbon-like heterochromatin patterns that were undetectable with DAPI counterstaining. These heterochromatin fibers were associated with nucleoli

Lunapark deficiency leads to an autosomal recessive neurodevelopmental phenotype with a degenerative course, epilepsy and distinct brain anomalies

LNPK encodes a conserved membrane protein that stabilizes the junctions of the tubular endoplasmic reticulum network playing crucial roles in diverse biological functions. Recently, homozygous variants in LNPK were shown to cause a neurodevelopmental disorder (OMIM#618090) in four patients displaying developmental delay, epilepsy and nonspecific brain malformations including corpus callosum hypoplasia and variable impairment of cerebellum. We sought to delineate the molecular and phenotypic spectrum of LNPK-related disorder. Exome or genome sequencing was carried out in 11 families. Thorough clinical and neuroradiological evaluation was performed for all the affected individuals, including review of previously reported patients. We identified 12 distinct homozygous loss-of-function variants in 16 individuals presenting with moderate to profound developmental delay, cognitive impairment, regression, refractory epilepsy and a recognizable neuroimaging pattern consisting of corpus callosum hypoplasia and signal alterations of the forceps minor ('ear-of-the-lynx' sign), variably associated with substantia nigra signal alterations, mild brain atrophy, short midbrain and cerebellar hypoplasia/atrophy. In summary, we define the core phenotype of LNPK-related disorder and expand the list of neurological disorders presenting with the 'ear-of-the-lynx' sign suggesting a possible common underlying mechanism related to endoplasmic reticulum-phagy dysfunction

A New Heterobinuclear FeIIICuII Complex with a Single Terminal FeIII–O(phenolate) Bond. Relevance to Purple Acid Phosphatases and Nucleases

A novel heterobinuclear mixed valence complex [Fe^IIICu^II(BPBPMP)(OAc)_2]ClO_4, 1, with the unsymmetrical N_5O_2 donor ligand 2-bis[{(2-pyridylmethyl)aminomethyl}-6-{(2-hydroxybenzyl)(2-pyridylmethyl)} aminomethyl]-4-methylphenol (H_2BPBPMP) has been synthesized and characterized. A combination of data from mass spectrometry, potentiometric titrations, X-ray absorption and electron paramagnetic resonance spectroscopy, as well as kinetics measurements indicates that in ethanol/water solutions an [Fe^III-(nu)OH-Cu^IIOH_2]+ species is generated which is the likely catalyst for 2,4-bis(dinitrophenyl)phosphate and DNA hydrolysis. Insofar as the data are consistent with the presence of an Fe_III-bound hydroxide acting as a nucleophile during catalysis, 1 presents a suitable mimic for the hydrolytic enzyme purple acid phosphatase. Notably, 1 is significantly more reactive than its isostructural homologues with different metal composition (Fe^IIIM^II, where M^II is Zn^II, Mn^II, Ni^II,or Fe^II). Of particular interest is the observation that cleavage of double-stranded plasmid DNA occurs even at very low concentrations of 1 (2.5 nuM), under physiological conditions (optimum pH of 7.0), with a rate enhancement of 2.7 x 10^7 over the uncatalyzed reaction. Thus, 1 is one of the most effective model complexes to date, mimicking the function of nucleases

Genotype–phenotype correlation in contactin-associated protein-like 2 (CNTNAP-2) developmental disorder

Contactin-associated protein-like 2 (CNTNAP2) gene encodes for CASPR2, a presynaptic type 1 transmembrane protein, involved in cell–cell adhesion and synaptic interactions. Biallelic CNTNAP2 loss has been associated with “Pitt-Hopkins-like syndrome-1” (MIM#610042), while the pathogenic role of heterozygous variants remains controversial. We report 22 novel patients harboring mono- (n = 2) and bi-allelic (n = 20) CNTNAP2 variants and carried out a literature review to characterize the genotype–phenotype correlation. Patients (M:F 14:8) were aged between 3 and 19 years and affected by global developmental delay (GDD) (n = 21), moderate to profound intellectual disability (n = 17) and epilepsy (n = 21). Seizures mainly started in the first two years of life (median 22.5 months). Antiseizure medications were successful in controlling the seizures in about two-thirds of the patients. Autism spectrum disorder (ASD) and/or other neuropsychiatric comorbidities were present in nine patients (40.9%). Nonspecific midline brain anomalies were noted in most patients while focal signal abnormalities in the temporal lobes were noted in three subjects. Genotype–phenotype correlation was performed by also including 50 previously published patients (15 mono- and 35 bi-allelic variants). Overall, GDD (p < 0.0001), epilepsy (p < 0.0001), hyporeflexia (p = 0.012), ASD (p = 0.009), language impairment (p = 0.020) and severe cognitive impairment (p = 0.031) were significantly associated with the presence of biallelic versus monoallelic variants. We have defined the main features associated with biallelic CNTNAP2 variants, as severe cognitive impairment, epilepsy and behavioral abnormalities. We propose CASPR2-deficiency neurodevelopmental disorder as an exclusively recessive disease while the contribution of heterozygous variants is less likely to follow an autosomal dominant inheritance pattern

Phytotoxicity of alkaloids, coumarins and flavonoids isolated from 11 species belonging to the Rutaceae and Meliaceae families

Meliaceae and Rutaceae families are known for the high diversity of their secondary metabolites, which include many groups that represent a rich source of structural diversity, and are good candidates as sources of allelochemicals that could be useful in agriculture. In the work described here the bioactivity profiles were evaluated for 3 alkaloids (1–3), 12 coumarins (4–15), 2 phenylpropanoic acid derivatives (16 and 17) and 14 flavonoids (18–31) from 11 species belonging to the Meliaceae and Rutaceae families. All compounds were tested in the wheat coleoptile bioassay and those that showed the highest activities were tested on the STS (Standard Target Species) Lepidium sativum (cress), Lactuca sativa (lettuce), Lycopersicon esculentum (tomato), and Allium cepa (onion). Most of the isolated compounds showed phytotoxic activity and graveoline (3), psoralen (8), and flavone (18) were the most active, with bioactivity levels similar to that of the commercial herbicide Logran1. The results indicate that these compounds could be involved as semiochemicals in the allelopathic interactions of these plant species