18 research outputs found
Nuovi metaboliti con attività antiproliferativa da ascidie del Mediterraneo
No full textGli estratti degli organismi sono stati analizzati monitorando il loro frazionamento, parallelamente ad une esame spettroscopico, anche attraverso uno screening farmacologico sulla linea cellulare tumorale WHEI 164 (fibrosarcoma di ratto)
Esteri alchilsolforici con attività antiproliferativa da diverse specie di ascidie del Mediterraneo
No full textStudio chimico condotto su campioni di Ascidia mentula, Microcosmus vulgaris, Halocynthia papillosa e Sidnyum turbinatu
La turbinammide, una nuova molecola con potente e selettiva attività citotossica, isolata dall'ascidia del Mediterraneo Sidnyum turbinatum
No full textE' stato esaminato il Sidnyum turbinatum, una specie di ascidiaceo coloniale piuttosto raro presente nel mar Mediterraneo, il cui estratto butanolico si era dimostrato attivo in uno screening farmacologico preliminare di citotossicità sulle cellule WHEI 164. Il frazionamento “bioassay-guided” di tale estratto ha portato all’isolamento della turbinamide, una poliidrossidotriacontanammide solfatata. Tale metabolita, la cui struttura non ha precedenti in letteratura, presenta una notevole attività citotossica selettiva nei confronti di cellule tumorali derivanti da tessuti nervosi, In particolare, la turbinammide si è dimostrata particolarmente citotossica nei confronti delle cellule di glioma di ratto della linea C6 e nei confronti delle cellule di neuroblastoma umano della linea SH-SY5Y. D’altro canto, l’attività citotossica non sembra essere particolarmente esercitata nei confronti di altre linee cellulari come quelle immunitarie (macrofagi J774, IC50=220 g/ml). La determinazione della complessa struttura della turbinammide è stata realizzata mediante una approfondita indagine spettroscopica realizzata con l’ausilio di diverse tecniche NMR monodimensionali 1H e 13C NMR e bidimensionali (COSY, HOHAHA, HMQC, HMBA, HMQC-HOHAHA)
Novel bioactive sulfated alkene and alkanes from the Mediterranean ascidian Halocynthia papillosa
No full textThree sulfated alkene and alkanes - (R)-2,6-dimethylheptyl sulfate (1), 6-methylheptyl sulfate (2a), and (E)-5-octenyl sulfate (3a) - with cytotoxic activity in vitro, have been isolated from the Mediterranean ascidian Halocynthia papillosa. The structures of the new compounds 2a and 3a have been elucidated by spectroscopic analysis
El vínculo epistemológico en la obra de Bruno Latour: Simetría e involucramiento en la constitución de redes
No full textLa obra de Bruno Latour irrumpió en las ciencias sociales en la década del ochenta con una propuesta compleja e innovadora que cuestiona la ontología dualista moderna sobre la que se sustentaron los conceptos de sociedad y naturaleza. Este artículo propone que Latour redefine el vínculo epistemológico entre el/la investigador/a y su objeto/sujeto de estudio de una forma alternativa tanto de las concepciones del consenso ortodoxo pre-kuhniano como de buena parte de las corrientes posempiristas, a partir de la cual construye una teoría positivista que se distancia de los cánones del modelo naturalista y cuyo principal objetivo es “ser fiel a la experiencia de las asociaciones”. Se pretende resaltar la importancia de la noción de simetría en su teoría, así como también de la dimensión política del trabajo científico en la constitución de redes. Por último, se reponen algunos cuestionamientos a la propuesta latoureana para hacer un balance crítico sobre sus aportes y déficits.Bruno Latour’s work broke into the social sciences in the eighties with a complex and innovative proposal that questions the modern dualist ontology on the concepts of society and nature. This article proposes that Latour redefines the epistemological link between the researcher and his object / subject of study in a way that is alternative from both the conceptions of the pre-Kuhnian orthodox consensus and from a good part of the post-empiricist approaches. Based on his epistemological link, the author builds a positivist theory that is distanced from the canons of the naturalistic model, whose main objective is “to be faithful to the experience of associations”. The article aims to highlight the importance of the notion of symmetry in his theory, as well as the political dimension of scientific work in the constitution of networks. Finally, the article recovers some questions on the Latourean proposal to make a critical balance on its contributions and deficits.Fil: Jones, Daniel Eduardo. Universidad de Buenos Aires. Facultad de Ciencias Sociales. Instituto de Investigaciones "Gino Germani". Área Salud y Población; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carbonelli, Marcos Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Centro de Estudios e Investigaciones Laborales; Argentina. Universidad Nacional Arturo Jauretche; Argentina. Universidad de Buenos Aires; ArgentinaFil: Paschkes Ronis, Matías. Universidad Nacional de San Martín. Instituto de Altos Estudios Sociales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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Chromatic Pupillometry Findings in Alzheimer's Disease
No full textIntrinsically photosensitive melanopsin retinal ganglion cells (mRGCs) are crucial for non-image forming functions of the eye, including the photoentrainment of circadian rhythms and the regulation of the pupillary light reflex (PLR). Chromatic pupillometry, using light stimuli at different wavelengths, makes possible the isolation of the contribution of rods, cones, and mRGCs to the PLR. In particular, post-illumination pupil response (PIPR) is the most reliable pupil metric of mRGC function. We have previously described, in post-mortem investigations of AD retinas, a loss of mRGCs, and in the remaining mRGCs, we demonstrated extensive morphological abnormalities. We noted dendrite varicosities, patchy distribution of melanopsin, and reduced dendrite arborization. In this study, we evaluated, with chromatic pupillometry, the PLR in a cohort of mild-moderate AD patients compared to controls. AD and controls also underwent an extensive ophthalmological evaluation. In our AD cohort, PIPR did not significantly differ from controls, even though we observed a higher variability in the AD group and 5/26 showed PIPR values outside the 2 SD from the control mean values. Moreover, we found a significant difference between AD and controls in terms of rod-mediated transient PLR amplitude. These results suggest that in the early stage of AD there are PLR abnormalities that may reflect a pathology affecting mRGC dendrites before involving the mRGC cell body. Further studies, including AD cases with more severe and longer disease duration, are needed to further explore this hypothesis
Retinal Nerve Fiber Layer thickness in Dominant Optic Atrophy: measurements by Optical Coherence tomography and correlation with age.
No full textPurpose: To measure the retinal nerve fiber layer (RNFL) thickness by means of optical coherence tomography
(OCT) in patients with dominant optic atrophy (DOA).
Design: Cross-sectional study.
Participants: Thirty-three patients from 15 pedigrees with DOA harboring heterozygous mutations in the
OPA1 gene and 43 healthy subjects were enrolled.
Methods: The RNFLs of DOA patients were studied by OCT and compared with those of 43 healthy subjects
matched for age and optic nerve head (ONH) size.
Main Outcome Measures: Retinal nerve fiber layer thickness.
Results: Dominant optic atrophy patients revealed a significant RNFL thickness reduction in all quadrants,
with a preferential involvement of the temporal and inferior sectors. The progressive decline of RNFL thickness
with age was similar to that observed in healthy subjects and was more evident in the 2 quadrants with higher
residual amounts of fibers, that is, the superior and the inferior. The temporal quadrant was profoundly depleted
of fiber so that the further rate of loss of microns per year is close to zero, whereas the nasal quadrant was spared
the most by neurodegeneration.
Conclusions: The present findings, taken in conjunction with the authors’ previous description of small ONH size
in DOA, strongly suggest that patients with this disease are born with fewer optic nerve axons and support the
hypothesis that subsequent visual loss depends on further age-related loss of fibers, which also occurs in controls.
Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed
in this article. Ophthalmology 2011;118:2076–2080 © 2011 by the American Academy of Ophthalmology
Loss of temporal retinal nerve fibers in Parkinson disease: a mitochondrial pattern?
No full textThe effect of autonomic perturbation (AP) on the central nervous system functioning is still largely unknown. Using an automated neck suction device to stimulate the carotid mechanoreceptors in the carotid sinus (parasympathetic pathway), operated synchronously with functional magnetic resonance imaging (fMRI) acquisition, we investigated the effects of AP on the activity of the brain at rest and when engaged in a visuo-spatial attention task. ECG was always recorded to index changes in autonomic function. At rest, AP induced increased activation in the insula and in the amygdala, which have been previously associated with the autonomic control and emotion processing, as well as in the caudate nucleus and in the medial temporal cortex, both implicated in cognitive functions. Despite a preserved performance during visuo-spatial attention task, AP induced increased reaction times and a positive modulation on the activation of the right posterior parietal cortex, the occipital cortex, the periaquiductal gray, and nuclei of the brainstem. We speculate that this modulation of brain activity represents, at different anatomical levels, a compensation mechanism to maintain cognitive efficiency under parasympathetic stimulation, which is traditionally considered as the system for energy regain and storage. In conclusion, this study provides the first evidence of a dynamic interaction between AP and higher level functions in humans
ChemInform Abstract: Sphinxolides E-G and Reidispongiolide C: Four New Cytotoxic Macrolides from the New Caledonian Lithistida Sponges N. superstes and R. coerulea.
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