52 research outputs found
Osteosarcoma periĂłstico: caso clĂnico
El osteosarcoma periĂłstico es un sarcoma raro que asienta en la superficie del hueso. Aunque algunos
autores lo incluyen en los osteosarcomas yuxtacorticales sus peculiaridades clĂnicas, radiolĂłgicas y anatomopatolĂłgicas
entre ellos que llevan a diferencias en el tratamiento y pronĂłstico le otorgan personalidad propia. Presentamos
un caso clĂnico de osteosarcoma periĂłstico en un varĂłn de 18 años, a nivel de fĂ©mur. Se realiza una revisiĂłn de
la bibliografĂa, señalando las principales caracterĂsticas de esta entidad.Periosteal osteosarcoma is a rare malignant neoplasm located on bone surface. Although some
authors include it among juxtacortical osteosarcoma, its clinical feature, imaging studies findings and histologic patterns
which lead to differences in the treatment and prognostic, give to it a peculiar identity. We report a case of an
18 years old man who had this tumour in his femur. We do a review of literature
Increased localization of APP-C99 in mitochondria-associated ER membranes causes mitochondrial dysfunction in Alzheimer disease
In the amyloidogenic pathway associated with Alzheimer disease (AD), the
amyloid precursor protein (APP) is cleaved by beta-secretase to generate
a 99-aa C-terminal fragment (C99) that is then cleaved by c-secretase to
generate the beta-amyloid (Ab) found in senile plaques. In previous
reports, we and others have shown that c-secretase activity is enriched
in mitochondria-associated endoplasmic reticulum (ER) membranes (MAM)
and that ER-mitochondrial connectivity and MAM function are upregulated
in AD. We now show that C99, in addition to its localization in
endosomes, can also be found in MAM, where it is normally processed
rapidly by c-secretase. In cell models of AD, however, the concentration
of unprocessed C99 increases in MAM regions, resulting in elevated
sphingolipid turnover and an altered lipid composition of both MAM and
mitochondrial membranes. In turn, this change in mitochondrial membrane
composition interferes with the proper assembly and activity of
mitochondrial respiratory supercomplexes, thereby likely contributing to
the bioenergetic defects characteristic of AD.We thank Drs. Orian Shirihai and Marc Liesa (UCLA) for assistance with
the Seahorse measurements, Dr. Huaxi Xu (Sanford Burnham Institute) for
the APP-DKO MEFs and Dr. Mark Mattson (NIH) for the PS1 knock-in mice,
Drs. Arancio and Teich for the APP-KO mice tissues used in these
studies, Dr. Hua Yang (Columbia University) for mouse husbandry, and
Drs. Marc Tambini, Ira Tabas, and Serge Przedborski for helpful
comments. This work was supported by the Fundacion Alfonso Martin
Escudero (to M.P.); the Alzheimer's Drug Discovery Foundation, the
Ellison Medical Foundation, the Muscular Dystrophy Association, the U.S.
Department of Defense W911NF-12-1-9159 and W911F-15-1-0169), and the J.
Willard and Alice S. Marriott Foundation (to E.A.S.); the U.S. National
Institutes of Health (P01-HD080642 and P01-HD032062 to E.A.S.; NS071571
and HD071593 to M.F.M.; R01-NS056049 and P50-AG008702 to G.D.P.;
1S10OD016214-01A1 to G.S.P. and F.P.M, and K01-AG045335 to E.A.-G.), the
Lucien Cote Early Investigator Award in Clinical Genetics from the
Parkinson's Disease Foundation (PDF-CEI-1364 and PDF-CEI-1240) to
C.G.-L., and National Defense Science and Engineering Graduate
Fellowship (FA9550-11-C-0028) to R.R.A.S
Dynamics of coherently pumped lasers with linearly polarized pump and generated fields
The influence of light polarization on the dynamics of an optically pumped single-mode laser with a homogeneously broadened four-level medium is theoretically investigated in detail. Pump and laser fields with either parallel or crossed linear polarizations are considered, as are typical in far-infrared-laser experiments. Numerical simulations reveal dramatically different dynamic behaviors for these two polarization configurations. The analysis of the model equations allows us to find the physical origin of both behaviors. In particular, the crossed-polarization configuration is shown to be effective in decoupling the pump and laser fields, thus allowing for the appearance of Lorenz-type dynamics
Mitochondrial division inhibitor-1 is neuroprotective in the A53T-α-synuclein rat model of Parkinson’s disease
Alpha-synuclein (α-syn) is involved in both familial and sporadic Parkinson’s disease (PD). One of the proposed pathogenic mechanisms of α-syn mutations is mitochondrial dysfunction. However, it is not entirely clear the impact of impaired mitochondrial dynamics induced by α-syn on neurodegeneration and whether targeting this pathway has therapeutic potential. In this study we evaluated whether inhibition of mitochondrial fission is neuroprotective against α-syn overexpression in vivo. To accomplish this goal, we overexpressed human A53T-α- synuclein (hA53T-α-syn) in the rat nigrostriatal pathway, with or without treatment using the small molecule Mitochondrial Division Inhibitor-1 (mdivi-1), a putative inhibitor of the mitochondrial fission Dynamin-Related Protein-1 (Drp1). We show here that mdivi-1 reduced neurodegeneration, α-syn aggregates and normalized motor function. Mechanistically, mdivi-1 reduced mitochondrial fragmentation, mitochondrial dysfunction and oxidative stress. These in vivo results support the negative role of mutant α-syn in mitochondrial function and indicate that mdivi-1 has a high therapeutic potential for PD
Amyloid Precursor Protein Is Trafficked and Secreted via Synaptic Vesicles
A large body of evidence has implicated amyloid precursor protein (APP) and its
proteolytic derivatives as key players in the physiological context of neuronal
synaptogenesis and synapse maintenance, as well as in the pathology of
Alzheimer's Disease (AD). Although APP processing and release are known to
occur in response to neuronal stimulation, the exact mechanism by which APP
reaches the neuronal surface is unclear. We now demonstrate that a small but
relevant number of synaptic vesicles contain APP, which can be released during
neuronal activity, and most likely represent the major exocytic pathway of APP.
This novel finding leads us to propose a revised model of presynaptic APP
trafficking that reconciles existing knowledge on APP with our present
understanding of vesicular release and recycling
Alpha-synuclein oligomer-selective antibodies reduce intracellular accumulation and mitochondrial impairment in alpha-synuclein exposed astrocytes
Laser application for optical glass polishing
Rapid generation of large area polished optical surfaces by high-power CO2 laser irradiation is shown. Results focus on glasses with high expansion coefficients (α≥10-5/°C) conventionally used in the optical industry. The technique involves active beam integration to obtain an intensity irradiation profile with a good uniformity over large spot sizes and is applied to preheated glass samples with initial rms roughness up to 500 nm. To find out the conditions for successful and reliable use of the proposed laser polishing method, the laser-driven heating process was monitored by means of the surface and depth temperature distributions. Whereas the former was determined in situ from the IR radiation emitted by the glass surface, the latter was obtained by comparison of the IR radiation emitted by the bulk sample with a theoretical model. Laser polishing of 5000 mm2 glass surfaces is reported and processes involved in the modification of the surface texture of the irradiated samples are described and discussed. © 1998 Society of Photo-Optical Instrumentation Engineers.Peer Reviewe
INSTABILITIES IN DOPPLER BROADENED OPTICALLY PUMPED FAR-INFRARED LASERS
On étudie le comportement dynamique d'un laser en anneau, unidirectionnel, sonomode et pompé optiquement, dont le milieu actif est composé par des atomes à trois niveaux affectés par élargissement Doppler. La formulation est basée sur un ensemble de 9N+1 équations réelles du type Maxwell-Bloch pour des ondes planes et approximation du champ moyen (N est le nombre de groupes de vitesse moléculaire considérés). Ce modèle prédit, pour un domain de valeurs des paramètres semblable à celui exploré expérimentalement par Weiss et Brock (Phys. Rev. Lett. 57 (1986) 2804), un comportement qui reproduit la plupart des traits principaux observés par ces auteurs ; en particulier le seuil de pompage pour les instabilités et la succession d'instabilités apparaissant par syntonization de la cavité et par variation de la puissance de pompage.We study the dynamic behaviour of a coherently pumped single-mode unidirectional ring laser with an active medium of Doppler broadened three-level atoms. Our formulation is based on a set of 9N+1 real equations of the plane-wave mean-field Maxwell-Bloch type (N is the number of velocity groups of molecules considered). This model predicts, for a parameter range of the type explored in the experiments by Weiss and Brock (Phys. Rev. Lett. 57 (1986) 2804), a behaviour that reproduces most of their main experimental features. These include the instability pump threshold and the sequence of instabilities ocurring on resonator tuning and on increasing pump strength
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