43 research outputs found
Sol-gel processing of actin to obtain homogeneous glasses at low temperatures
International audienc
Purification of a troponin I-like factor from pig platelet
AbstractA troponin I-like factor has been purified from pig platelet by G150 Sephadex filtration of a low ionic strength extract, acidification at pH 4.2, ion exchange on DE-52 cellulose, and affinity chromatography on calmodulin-Sepharose. This protein (Mr 17000), together with pig brain calmodulin and platelet tropomyosin, is able to participate to the reconstitution in vitro of a thin filament-like complex which modulates with 55% calcium sensitivity11Calcium sensitivity = [1 - (ATPase EGTA/ATPase calcium)] × 100 the platelet actin-activated Mg2+-dependent ATPase activity of rabbit skeletal muscle myosin
Rheological properties of cellular plasms and cryobehavior : studies on early embryos and by in vitro simulations
International audienc
Une nouvelle approche du cryocomportement cellulaire des systemes vivants
National audienc
Characterization of inflammatory reaction in upper airways of cystic fibrosis patients
Inflammatory cell populations have not been yet precisely evaluated in cystic fibrosis (CF) airways. We intended to characterize morphological modifications, inflammatory cell infiltration and cell proliferation in nasal tissues obtained from 15 CF patients and from 6 non-CF patients with nasal polyposis. Morphological analysis showed an intense inflammatory infiltration in CF and non-CF tissues with only few modifications in the epithelium from CF tissues. Inflammatory cell populations characterized by specific immunolabeling were quantified, showing a predominance of macrophages and T- and B-lymphocytes and only moderate numbers of neutrophils in CF tissues; in non-CF polyps, lymphocytes and eosinophils were abundant. Proliferating cell percentages quantified after proliferating cell nuclear antigen immunolabeling were 5.3+4.1% (mean t SD) in CF polyps and 3.1+-1.2% in non-CF polyps in epithelium but were very low in lamina propria. Intense inflammation in nasal tissues from CF patients is therefore dominated by macrophages and lymphocytes rather than by neutrophils. While morphology is preserved, proliferation is high in epithelium from CF polyps. These findings should be regarded in the future for a better understanding of inflammation in CF airway disease
Augmentation de l'association F-actine/alpha-actinine en presence de 1,2-propanediol
National audienc
Rheological changes in mammalian egg cytoskeleton in response to cold adaptation
National audienc
Isolation of actin-associated proteins from Caenorhabditis elegans oocytes and their localization in the early embryo.
The actin cytoskeleton plays an important, but poorly understood, role in the development of multicellular organisms. To help illuminate this role, we used actin filament affinity chromatography to isolate actin binding proteins from large quantities of Caenorhabditis elegans oocytes. To examine how these proteins might be involved in early development, we prepared antibodies against some of them and determined their distribution in fixed embryos. Three of these proteins co-localize with different subsets of the embryonic actin cytoskeleton. One co-localizes with actin to all cell cortices. The second oscillates between the nucleus and cortex in a cell-cycle-dependent manner. The third is asymmetrically enriched at the anterior cortex of one-cell embryos, showing a temporal and spatial localization suggestive of a function in generating developmental asymmetry. We conclude that biochemistry is a feasible and useful approach in the study of early C. elegans development, and that the embryonic actin cytoskeleton is regulated in a complex fashion in order to carry out multiple, simultaneous functions
Characterization of inflammatory reaction in upper airways of cystic fibrosis patients
Inflammatory cell populations have not been
yet precisely evaluated in cystic fibrosis (CF) airways.
We intended to characterize morphological modifications,
inflammatory cell infiltration and cell
proliferation in nasal tissues obtained from 15 CF
patients and from 6 non-CF patients with nasal
polyposis. Morphological analysis showed an intense
inflammatory infiltration in CF and non-CF tissues with
only few modifications in the epithelium from CF
tissues. Inflammatory cell populations characterized by
specific immunolabeling were quantified, showing a
predominance of macrophages and T- and B-lymphocytes
and only moderate numbers of neutrophils in CF
tissues; in non-CF polyps, lymphocytes and eosinophils
were abundant. Proliferating cell percentages quantified
after proliferating cell nuclear antigen immunolabeling
were 5.3+4.1% (mean t SD) in CF polyps and 3.1?1.2%
in non-CF polyps in epithelium but were very low in
lamina propria. Intense inflammation in nasal tissues
from CF patients is therefore dominated by macrophages
and lymphocytes rather than by neutrophils. While
morphology is preserved, proliferation is high in
epithelium from CF polyps. These findings should be
regarded in the future for a better understanding of
inflammation in CF airway disease