6 research outputs found
Comparative chondrogenesis of human cells in a 3D integrated experimental/computational mechanobiology model
We present an integrated experimentalâcomputational
mechanobiology model of chondrogenesis. The
response of human articular chondrocytes to culture medium
perfusion, versus perfusion associated with cyclic pressurisation,
versus non-perfused culture, was compared in a pellet
culture model, and multiphysic computation was used
to quantify oxygen transport and flow dynamics in the various
culture conditions. At 2 weeks of culture, the measured
cell metabolic activity and the matrix content in
collagen type II and aggrecan were greatest in the perfused+
pressurised pellets. The main effects of perfusion
alone, relative to static controls, were to suppress collagen
type I and GAG contents, which were greatest in
the non-perfused pellets. All pellets showed a peripheral
layer of proliferating cells, which was thickest in the perfused
pellets, and most pellets showed internal gradients
in cell density and matrix composition. In perfused pellets,
the computed lowest oxygen concentration was 0.075mM
(7.5% tension), the maximal oxygen flux was
477.5 nmol/m2/s and the maximal fluid shear stress, acting
on the pellet surface, was 1.8mPa (0.018 dyn/cm2). In the
non-perfused pellets, the lowest oxygen concentration was
0.003mM (0.3% tension) and the maximal oxygen flux was
102.4nmol/m2/s.Alocal correlationwas observed, between
the gradients in pellet properties obtained from histology,
and the oxygen fields calculated with multiphysic simulation.
Our results showup-regulation of hyalinematrix protein
production by human chondrocytes in response to perfusion
associated with cyclic pressurisation. These results could be
favourably exploited in tissue engineering applications
MACI - a new era?
Full thickness articular cartilage defects have limited regenerative potential and are a significant source of pain and loss of knee function. Numerous treatment options exist, each with their own advantages and drawbacks. The goal of this review is to provide an overview of the problem of cartilage injury, a brief description of current treatment options and outcomes, and a discussion of the current principles and technique of Matrix-induced Autologous Chondrocyte Implantation (MACI). While early results of MACI have been promising, there is currently insufficient comparative and long-term outcome data to demonstrate superiority of this technique over other methods for cartilage repair
PCR detection of Lactobacillus sanfranciscensis in sourdough and Panettone baked product
Sourdoughs, in which Lactobacillus sanfranciscensis is the predominant bacterial species, are distinctive of some traditional Italian sweet baked products like Panettone. The direct extraction of amplifiable bacterial DNA from products subjected to heat treatment represents a valid tool to identify and trace microbial species originally present in the food matrices. Three types of protocols for the isolation and clean-up of DNA (CTAB, Wizard (R) DNA Clean-Up System, NucleoSpin (R) Food) were applied on mother, final dough and end-product samples and compared through the determination of the maximum amplifiable dilution by a PCR reaction targeting two fragments (1460 and 153 bp long) of 16S rDNA region of Lb. sanfranciscensis. CTAB extracting protocol was revealed to be the best for isolating DNA. In dough samples the amplification with the 153 bp fragment showed signals at concentration levels that are comparable with the values obtained from the plate counts, and two log cycles higher than those found with the amplification targeting the 1460 bp fragment. In the cooked samples only the 153 bp amplicon was detected, indicating that oven cooking degrades DNA into small fragments