Cryopreservation by vitrification of small biological elements Baudot, A. (Centre National de la Recherche Scientifique, Grenoble (France). Centre de Recherches sur les tres Basses Temperatures); Guttin, C; Skowron, O ...
Revue Generale du Froid (France),
(Oct 2000), Letnik:
90, Številka:
1007
Journal Article
La vitrification est actuellement la voie de recherche la plus prometteuse pour conserver durablement des systemes biologiques complexes avant leur transplantation. Elle permet d'eviter toute ...formation de cristaux de glace dans les tissus lors de leur refroidissement jusqu'aux temperatures cryogeniques. Mais c'est un procede delicat qui impose l'utilisation de solutions contenant des antigels biocompatibles appeles cryoprotecteurs, ainsi que des vitesses de refroidissement et de rechauffement relativement elevees. Le refroidissement rapide est necessaire pour figer les liquides dans un etat solide sans cristal de glace. Mais le verre ainsi forme est fragile. Pour eviter l'apparition de fractures, on propose de proceder a un recuit autour de la temperature de transition vitreuse afin de relacher les contraintes emprisonnees dans le verre. Cette methode est detaillee pour une solution aqueuse contenant 45 % (p/p) de 1,2-propanediol dans de l'eau desionisee et les differentes etapes de cette vitrification sont presentees. Au niveau du rechauffement, les ondes electromagnetiques semblent actuellement les plus adaptees pour rechauffer vite et uniformement. Le systeme de rechauffement prototype mis au point pour la cryopreservation des aortes de lapin est decrit. Il fonctionne a 13 MHz et a permis de rechauffer sans cristallisation de glace quelques cm3 de verre forme avec la solution precisee
The New IRAM KID Arrays 2 (NIKA2) consortium has just finished installing and commissioning a millimetre camera on the IRAM 30 m telescope. It is a dual-band camera operating with three frequency ...multiplexed kilo-pixels arrays of Lumped Element Kinetic Inductance Detectors (LEKID) cooled at 150 mK, designed to observe the intensity and polarisation of the sky at 260 and 150 GHz (1.15 and 2 mm). NIKA2 is today an IRAM resident instrument for millimetre astronomy, such as Intra Cluster Medium from intermediate to distant clusters and so for the follow-up of Planck satellite detected clusters, high redshift sources and quasars, early stages of star formation and nearby galaxies emission. We present an overview of the instrument performance as it has been evaluated at the end of the commissioning phase.
Background
Diagnosis of infiltrative small intestinal (SI) disease in cats is challenging, and debate continues regarding optimal biopsy techniques. Ultrasonography may facilitate selection of biopsy ...type and location.
Hypothesis/Objectives
Assess ability of ultrasonography to predict histologic lesions by SI segment and tissue layer.
Animals
One‐hundred sixty‐nine cats that had abdominal ultrasonography and full‐thickness SI biopsies performed.
Methods
Ultrasonographic images and full‐thickness biopsy samples were retrospectively reviewed, and each SI wall layer evaluated for lesions according to published standards.
Results
Ultrasonographic SI lesions were present in 132 cats (63 duodenum; 115 jejunum; 71 ileum). Samples were obtained at laparotomy (60) or necropsy (109). Ultrasonographic abnormalities had high positive predictive value (PPV) for histologic lesions (duodenum, 82.0%; 95% confidence interval CI, 68.6‐91.4; jejunum, 91.0%; 95% CI, 81.5‐96.6; ileum, 88.1%; 95% CI, 74.4‐96.0), but poor negative predictive value (duodenum, 27.1%; 95% CI, 17.2‐39.1; jejunum, 27.3%; 95% CI, 10.7‐50.2; ileum, 40.4%; 95% CI, 26.4‐55.7). The ability of ultrasonography to predict histologic lesions in this population, which had high disease prevalence (SI histologic lesions in 78.1% of cats) was high for mucosal lesions (PPV, 72.7%‐100%) but low for submucosal or muscularis lesions (PPV, 18.9%‐57.1%).
Conclusions and Clinical Importance
In a population with high disease prevalence, most cats with SI mucosal ultrasonographic lesions will have mucosal histologic lesions. Small intestinal submucosal and muscularis ultrasonographic lesions are not predictive of histologic disease in those layers, suggesting that full‐thickness biopsy may not be essential in these cats. Ultrasonography may help guide decisions about biopsy type in individual cats.
Le projet a consisté à développer une nouvelle stratégie thérapeutique basée sur les spécificités moléculaires intrinsèques des tumeurs solides afin de personnaliser le traitement en le reliant ...directement au diagnostic de la tumeur (theranostic). Les tumeurs cérébrales et les tumeurs de vessies sont deux exemples de tumeurs solides particulièrement agressives. Ces deux types de tumeurs sont classés en plusieurs sous-groupes ayant leur propre profil moléculaire. Les microARN (ou miR) sont des molécules synthétisées naturellement par les cellules. Ces molécules peuvent avoir un rôle d’oncogène ou de suppresseur de tumeurs et leur expression est fortement dérégulée dans les tumeurs. Ainsi la mesure des taux d’expression de quelques microARN dans un échantillon de tissu tumoral permet de réaliser la distinction des gliomes de haut grade par rapport à ceux de bas grade. Dans le cadre du traitement, la thérapie envisagée consiste à moduler l’expression des microARN dérégulés dans les tumeurs. L’approche évaluée consiste à contrer l’expression de microARN oncogènes surexprimés à l’aide d’un antimicroARN (antimiR). Ce type de molécule est chimiquement semblable aux molécules d’ARN naturellement présentes dans la cellule. Pour une meilleure efficacité de cette stratégie thérapeutique, l’autre partie du projet a consisté à optimiser le transport de l’antimiR et l’effet de la thérapie. Pour introduire l’antimicroARN au plus près du coeur de la tumeur, il a été prévu de réaliser un couplage entre un antimiR et un dérivé de chalcones pénétrant facilement dans les cellules et doué de propriétés antitumorales, cette combinaison paraît prometteuse.
Solid malignant tumors have molecular characteristics that clearly distinguish them from healthy tissue. The project is to develop a new therapeutic strategy based on these molecular characteristics. We set up a new therapeutic approach so as to customize treatment by connecting it directly to the diagnosis of the tumor (theranostic approach).Brain tumours and bladder tumours are two examples of particularly aggressive solid tumours. These two types of tumors are classified into several subgroups that have their own molecular profiles. The microRNAs (miR) are molecules naturally synthesized by cells. These molecules may have a role of oncogene or tumour suppressors whose expression is strongly deregulated in tumours. So the assessment of the expression levels of few microRNA allows the distinction of gliomas of high grade compared to low grade.To set up the new therapy we needed to modulate the expression of microRNAs deregulated in tumors. The proposed approach was to counter the expression of oncogenic microRNAs overexpressed using an antimicroARN (antimiR). This type of molecule is chemically similar to the naturally occurring RNA molecules in the cells. For a better efficiency of this new therapeutic strategy, we tried to optimize the transport of the antimiR to increase the therapeutic effect. To vectorize the therapeitic antimiR to the heart of the tumor, we envisioned to chemically combine the antimiR to a cell-penetrating antitumoral compound. Chalcones derivatives which are hydrophobic have this capability. A combination of the two molecules (antimicroARN and chalcone) was evaluated and the results appeared promising.
Homfly polynomials of knots and links are evaluated on computers by using an algebraic version, with Gauss codes, of the skein-template algorithm. The computer codes are written with the language C ...whose structure is particularly suitable to such evaluations. Jones, Conway and Alexander polynomials may then be readily obtained as special cases.
Thermal lens oscillations, and associated hot-wire experiments, pertain to a class of instabilities produced when the free surface of a liquid is locally heated from below, generalizing to some ...extent the classical Benard-Marangoni instabilities 1-8. They provided a host of original observations, including what is seemingly the first evidence of a type-II intermittency in hydrodynamical experiments or the discovery of a new kind of propagating waves exhibiting a significant 1D-character. After two decades of study, this class of instabilities now receives a rather classical aspect 9 and deserves a review, which is presented in this paper. Beside the presentation of what is known and understood nowadays, the opportunity is taken to stress unsolved issues, therefore opening the way to future studies. This review completes and up-to-dates a previous one published one decade ago 10.
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