Search results for "Gel"

Expression of Gelatinases (MMP-2, MMP-9) in human articular cartilage

2013

Osteoarthritis (OA) is a chronic degenerative joint disorder characterized by destruction of the articular cartilage, subchondral bone alterations and synovitis. Matrix metalloproteinases (MMPs) are expressed in joint tissues of patients with osteoarthritis (OA). The objective of this study was to define the steady state levels of two different MMPs to provide more insight into the role of MMPs in cartilage destruction in OA. We investigated the expression of gelatinases through immunohistochemistry Our results show that high levels of MMP-2 and MMP-9 are present in OA and suggest that once these MMPs are fully activated they may contribute to the cartilage destruction in OA.

κ-Carrageenan and PVA blends as bioinks to 3D print scaffolds for cartilage reconstruction.

2022

3D printing of polymeric scaffolds and autologous stem cells is a promising tool for damaged facial cartilage reconstruction surgeries. To this end, suitable bioinks are needed to generate scaffolds with the required morphological and functional features. We formulated hydrogel bioinks using k-Carrageen (kC) and poly(vinyl alcohol) (PVA) in three different weight ratios. The kC gives the systems the ability to undergo rapid sol-to-gel transitions upon cooling from 60 °C and above to body temperature, while the PVA is used as rheology modifier and porogen. The latter is crosslinked after molding or printing by freeze-thaw cycling for 1 day (FT1) or 5 days (FT5). To select the most suitable f…

Remembering a past princess : Catherine Jagiellon and the construction of national narratives in Sweden and Finland

2019

This chapter tackles the role a Jagiellonian princess, Catherine Jagiellon, has been given in Swedish and Finnish history culture. It illustrates how her figure has entered the historical-cultural memory of both countries, forging and re-forging their national self-image from the end of the sixteenth century through the Cold War, and into contemporary school history teaching. The chapter highlights the differences as well as the similarities of collective memory and history culture associated with Catherine Jagiellon in two Nordic countries with a shared history. It focuses on largely on physical sites of memory such as archives, museums, cathedrals, chapels, castles, commemorative monument…

Exceptional affinity of nanostructured organic-inorganic hybrid materials towards dioxygen: confinement effect of copper complexes

2007

We report the exceptional reactivity towards dioxygen of a nanostructured organic-inorganic hybrid material due to the confinement of copper cyclam within a silica matrix. The key step is the metalation reaction of the ligand, which can occur before or after xerogel formation through the sol-gel process. The incorporation of a Cu(II) center into the material after xerogel formation leads to a bridged Cu(I)/Cu(II) mixed-valence dinuclear species. This complex exhibits a very high affinity towards dioxygen, attributable to auto-organization of the active species in the solid. The remarkable properties of these copper complexes in the silica matrix demonstrate a high cooperative effect for O(2…

Prediction and Control: The Specific Role of Business Angels in the Investment Process

2019

International audience; Entrepreneurs and related investors (business angels and venture capitalists) rely on different types of rationalities. Extant research suggests that conflicts resulting from misunderstanding can emerge between entrepreneurs and investors when they adopt different rationalities but must switch those rationalities because of the maturity of their ventures and the degree of uncertainty they face. Relying on three in-depth case studies, this research contributes to both entrepreneurship and effectuation literature by emphasizing the specific role of business angels in helping entrepreneurs switch rationalities when necessary to attract funding resources from venture cap…

Electrophoresis of Unlabeled Proteins in a Sequencing Gel Apparatus

2000

Purification and characterization of a pore-forming protein from the marine sponge Tethya lyncurium

1992

A pore-forming protein was detected and purified for the first time from a marine sponge (Tethya lyncurium). The purified protein has a polypeptide molecular mass of 21 kDa and a pI of 6.4. Tethya pore-forming protein (also called Tethya hemolysin) rapidly lysed erythrocytes from a variety of organisms. After binding to target membranes, the hemolysin resisted elution with EDTA, salt or solutions of low ionic strength and hence resembled an integral membrane protein. Erythrocytes could be protected from hemolysis induced by Tethya hemolysin by addition of 30 mM dextran 4 (4-6 kDa; equivalent hydrodynamic diffusion radius, 1.75-2.3 nm) to the extracellular medium, but not by addition of unch…

Evidence for a selective and electroneutral K+/H+-exchange in Saccharomyces cerevisiae using plasma membrane vesicles

1996

The existence of a K+/H+ transport system in plasma membrane vesicles from Saccharomyces cerevisiae is demonstrated using fluorimetric monitoring of proton fluxes across vesicles (ACMA fluorescence quenching). Plasma membrane vesicles used for this study were obtained by a purification/reconstitution protocol based on differential and discontinuous sucrose gradient centrifugations followed by an octylglucoside dilution/gel filtration procedure. This method produces a high percentage of tightly-sealed inside-out plasma membrane vesicles. In these vesicles, the K+/H+ transport system, which is able to catalyse both K+ influx and efflux, is mainly driven by the K+ transmembrane gradient and ca…

Properties of the yeast nuclear histone deacetylase.

1994

A nuclear histone deacetylase from yeast was partially purified and some of its characteristics were studied. Histone deacetylase activity was stimulated in vitro by high-mobility-group nonhistone chromatin proteins 1 and 2 and ubiquitin and inhibited by spermine and spermidine, whereas n-butyrate had no significant inhibitory effect. Like the mammalian enzyme, partially purified histone deacetylase from yeast was strongly inhibited by trichostatin A. However, in crude extract preparations the yeast enzyme was not inhibited and treatment with trichostatin in vivo did not show any effect, either on the histone acetylation level or on cell viability. At low ionic strength, the enzyme can be i…

Biocompatible hydrogels based on hyaluronic acid cross-linked with a polyaspartamide derivative as delivery systems for epithelial limbal cells.

2011

The aim of this work was to evaluate the potential use of hydrogels based on hyaluronic acid (HA) chemically cross-linked with α,β-poly(N-2-hydroxyethyl) (2-aminoethylcarbamate)-D,L-aspartamide (PHEA-EDA) as substitutes for the amniotic membrane able to release limbal cells for corneal regeneration. Hydrogels, shaped as films, with three different molar ratios (X) between PHEA-EDA and HA (X = 0.5, 1.0 and 1.5) have been investigated. First, it has been evaluated their swelling ability, hydrolytic resistance in simulated physiological fluid and cell compatibility by using human dermal fibroblasts chosen as a model cell line. Then adhesion studies in comparison with collagen gel, have been pe…