15 research outputs found
Culture of equine fibroblast-like synoviocytes on synthetic tissue scaffolds towards meniscal tissue engineering: a preliminary cell-seeding study
Introduction. Tissue engineering is a new methodology for addressing meniscal injury or loss. Synovium may be an ideal source of cells for in vitro meniscal fibrocartilage formation, however, favorable in vitro culture conditions for synovium must be established in order to achieve this goal. The objective of this study was to determine cellularity, cell distribution, and extracellular matrix (ECM) formation of equine fibroblast-like synoviocytes (FLS) cultured on synthetic scaffolds, for potential application in synovium-based meniscal tissue engineering. Scaffolds included open-cell poly-L-lactic acid (OPLA) sponges and polyglycolic acid (PGA) scaffolds cultured in static and dynamic culture conditions, and PGA scaffolds coated in poly-L-lactic (PLLA) in dynamic culture conditions.Materials and Methods. Equine FLS were seeded on OPLA and PGA scaffolds, and cultured in a static environment or in a rotating bioreactor for 12 days. Equine FLS were also seeded on PGA scaffolds coated in 2% or 4% PLLA and cultured in a rotating bioreactor for 14 and 21 days. Three scaffolds from each group were fixed, sectioned and stained with Masson’s Trichrome, Safranin-O, and Hematoxylin and Eosin, and cell numbers and distribution were analyzed using computer image analysis. Three PGA and OPLA scaffolds from each culture condition were also analyzed for extracellular matrix (ECM) production via dimethylmethylene blue (sulfated glycosaminoglycan) assay and hydroxyproline (collagen) assay. PLLA coated PGA scaffolds were analyzed using double stranded DNA quantification as areflection of cellularity and confocal laser microscopy in a fluorescent cell viability assay.Results. The highest cellularity occurred in PGA constructs cultured in a rotating bioreactor, which also had a mean sulfated glycosaminoglycan content of 22.3 µg per scaffold. PGA constructs cultured in static conditions had the lowest cellularity. Cells had difficulty adhering to OPLA and the PLLA coating of PGA scaffolds; cellularity was inversely proportional to the concentration of PLLA used. PLLA coating did not prevent dissolution of the PGA scaffolds. All cell scaffold types and culture conditions produced non-uniform cellular distribution.Discussion/Conclusion. FLS-seeding of PGA scaffolds cultured in a rotating bioreactor resulted in the most optimal cell and matrix characteristics seen in this study. Cells grew only in the pores of the OPLA sponge, and could not adhere to the PLLA coating of PGA scaffold, due to the hydrophobic property of PLA. While PGA culture in a bioreactor produced measureable GAG, no culture technique produced visible collagen. For this reason, and due to the dissolution of PGA scaffolds, the culture conditions and scaffolds described here are not recommended for inducing fibrochondrogenesis in equine FLS for meniscal tissue engineering
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Culture of equine fibroblast-like synoviocytes on synthetic tissue scaffolds towards meniscal tissue engineering: a preliminary cell-seeding study
INTRODUCTION: Tissue engineering is a new methodology for addressing meniscal
injury or loss. Synovium may be an ideal source of cells for in vitro meniscal fibrocartilage
formation, however, favorable in vitro culture conditions for synovium must be
established in order to achieve this goal. The objective of this study was to determine
cellularity, cell distribution, and extracellular matrix (ECM) formation of equine
fibroblast-like synoviocytes (FLS) cultured on synthetic scaffolds, for potential application
in synovium-based meniscal tissue engineering. Scaffolds included open-cell
poly-L-lactic acid (OPLA) sponges and polyglycolic acid (PGA) scaffolds cultured
in static and dynamic culture conditions, and PGA scaffolds coated in poly-L-lactic
(PLLA) in dynamic culture conditions.
MATERIALS AND METHODS: Equine FLS were seeded on OPLA and PGA scaffolds, and
cultured in a static environment or in a rotating bioreactor for 12 days. Equine FLS
were also seeded on PGA scaffolds coated in 2% or 4% PLLA and cultured in a
rotating bioreactor for 14 and 21 days. Three scaffolds from each group were fixed,
sectioned and stained with Masson’s Trichrome, Safranin-O, and Hematoxylin and
Eosin, and cell numbers and distribution were analyzed using computer image analysis.
Three PGA and OPLA scaffolds from each culture condition were also analyzed
for extracellular matrix (ECM) production via dimethylmethylene blue (sulfated
glycosaminoglycan) assay and hydroxyproline (collagen) assay. PLLA coated PGA
scaffolds were analyzed using double stranded DNA quantification as a reflection of
cellularity and confocal laser microscopy in a fluorescent cell viability assay.
RESULTS: The highest cellularity occurred in PGA constructs cultured in a rotating
bioreactor, which also had a mean sulfated glycosaminoglycan content of 22.3 μg per
scaffold. PGA constructs cultured in static conditions had the lowest cellularity. Cells
had difficulty adhering to OPLA and the PLLA coating of PGA scaffolds; cellularity
was inversely proportional to the concentration of PLLA used. PLLA coating did not
prevent dissolution of the PGA scaffolds. All cell scaffold types and culture conditions
produced non-uniformcellular distribution. DISCUSSION/CONCLUSION: FLS-seeding of PGA scaffolds cultured in a rotating bioreactor resulted in the most optimal cell and matrix characteristics seen in this study.
Cells grew only in the pores of the OPLA sponge, and could not adhere to the PLLA
coating of PGA scaffold, due to the hydrophobic property of PLA. While PGA culture
in a bioreactor produced measureable GAG, no culture technique produced
visible collagen. For this reason, and due to the dissolution of PGA scaffolds, the
culture conditions and scaffolds described here are not recommended for inducing
fibrochondrogenesis in equine FLS for meniscal tissue engineering.Keywords: Stifle,
Orthopedics,
Bioreactors,
Fibroblast-like synoviocytes,
Meniscus,
Cell scaffolds,
Tissue engineering,
Bioengineering,
Veterinary Medicine,
Surgery and Surgical Specialties,
EquineThis is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by PeerJ. The published article can be found at: https://peerj.com/
Development of an in vitro three dimensional loading-measurement system for long bone fixation under multiple loading conditions: a technical description
The purpose of this investigation was to design and verify the capabilities of an in vitro loading-measurement system that mimics in vivo unconstrained three dimensional (3D) relative motion between long bone ends, applies uniform load components over the entire length of a test specimen, and measures 3D relative motion between test segment ends to directly determine test segment construct stiffness free of errors due to potting-fixture-test machine finite stiffness
Measurement of the Inclusive Semi-electronic Branching Fraction
Using the angular correlation between the emitted in a decay and the emitted in the subsequent decay, we have measured the branching fraction for the
inclusive semi-electronic decay of the meson to be: {\cal B}(D^0
\rightarrow X e^+ \nu) = [6.64 \pm 0.18 (stat.) \pm 0.29 (syst.)] \%. The
result is based on 1.7 fb of collisions recorded by the CLEO II
detector located at the Cornell Electron Storage Ring (CESR). Combining the
analysis presented in this paper with previous CLEO results we find,
\frac{{\cal B} (D^0 \rightarrow X e^+ \nu)}
{{\cal B} (D^0 \rightarrow K^- \pi^+)}
= 1.684 \pm 0.056 (stat.) \pm 0.093(syst.) and
\frac{{\cal B}(D\rightarrow K^-e^+\nu)}
{{\cal B}(D\rightarrow Xe^+\nu)}
= 0.581 \pm 0.023 (stat.) \pm 0.028(syst.).
The difference between the inclusive rate and the sum of the measured
exclusive branching fractions (measured at CLEO and other experiments) is of the inclusive rate.Comment: Latex file, 33pages, 4 figures Submitted to PR
Risk factors associated with cast complications in horses: 398 cases (1997-2006)
OBJECTIVE
To determine the frequency of and risk factors for complications associated with casts in horses.
DESIGN
Multicenter retrospective case series.
ANIMALS
398 horses with a half-limb or full-limb cast treated at 1 of 4 hospitals.
PROCEDURES
Data collected from medical records included age, breed, sex, injury, limb affected, time from injury to hospital admission, surgical procedure performed, type of cast (bandage cast [BC; fiberglass tape applied over a bandage] or traditional cast [TC; fiberglass tape applied over polyurethane resin-impregnated foam]), limb position in cast (flexed, neutral, or extended), and complications. Risk factors for cast complications were identified via multiple logistic regression.
RESULTS
Cast complications were detected in 197 of 398 (49%) horses (18/53 [34%] horses with a BC and 179/345 [52%] horses with a TC). Of the 197 horses with complications, 152 (77%) had clinical signs of complications prior to cast removal; the most common clinical signs were increased lameness severity and visibly detectable soft tissue damage Cast sores were the most common complication (179/398 [45%] horses). Casts broke for 20 (5%) horses. Three (0.8%) horses developed a bone fracture attributable to casting Median time to detection of complications was 12 days and 8 days for horses with TCs and BCs, respectively. Complications developed in 71%, 48%, and 47% of horses with the casted limb in a flexed, neutral, and extended position, respectively. For horses with TCs, hospital, limb position in the cast, and sex were significant risk factors for development of cast complications.
CONCLUSIONS AND CLINICAL RELEVANCE
Results indicated that 49% of horses with a cast developed cast complications