186,155 research outputs found
Inhibition of vein graft intimal hyperplasia by free radical quenching and photodynamic therapy
No full textLaser-Induced Shock Waves Enhance Sterilization of Infected Vascular Prosthetic Grafts
No full textBackground and Objective: Bacteria that cause infection
of vascular prosthetic grafts produce an exopolysaccharide
matrix known as biofilm. Growth in biofilms
protects the bacteria from leukocytes, antibodies and
antimicrobial drugs. Laser-generated shock waves (SW)
can disrupt biofilms and increase drug penetration. This
study investigates the possibility of increasing antibiotic
delivery and sterilization of vascular prosthetic graft.
Study Design/Materials and Methods: Strains of
Staphylococcus epidermidis and S. aureus were isolated
from infected prosthetic grafts obtained directly from
patients. Dacron grafts were inoculated with the isolated
bacteria, which were allowed to form adherent bacterial
colonies. The colonized grafts underwent the following
treatments: (a) antibiotic (vancomycin) alone; (b) antibiotic
and SW (c) saline only; and (d) saline and SW. Six hours
after treatment, the grafts were sonicated, the effluent was
cultured and the colony forming units (CFU) were counted.
Results: CFU recovered from control grafts colonized by
S. epidermidis were comparable: saline, 3.05108 and
saline SW 3.31108. The number of S. epidermidis CFU
diminished to 7.61106 after antibiotic treatment but the
combined antibiotic SW treatment synergistically
decreased CFU number to 1.27104 (P<0.001). S. aureus
showed a higher susceptibility to the antibiotic: 2.26106
CFU; antibiotic SW treatment also had an incremental
effect: 8.27104 CFU (P<0.001).
Conclusions: This study demonstrates that laser-generated
shock waves have no effects alone, but can enhance
the effectiveness of antibiotics against bacteria associated
with prosthetic vascular graft biofilms, suggesting that
this treatment may be of value as adjunctive therapy for
prosthetic graft infections. Lasers Surg. Med. 29:448–454,
2001. ß 2001 Wiley-Liss, Inc
Photochemically Modulated Endothelial Cell Thrombogenicity via the Thrombomodulin/Tissue Factor Pathway
No full textAnti-Neutrophil Antibody and Anti-C5 Antibody Allows Inhibition of Acute Vein Graft Thrombosis After Photochemical Therapy
No full textFree Radical Quenching Enables Photodynamic Therapy Inhibition of Vein Graft Intimal Hyperplasia
No full textMassachusetts General Hospital, Harvard Medical School, Boston, Massachusett
Improved sterilization of prosthetic vascular graft using shock waves
No full textAbstract published on Lasers Surg Med 2001, Suppl. 2
Photodynamic therapy inhibits intimal hyperplasia in arteriousvenous fistula
No full textMassachusetts General Hospital, Harvard Medical School, Boston, Massachusett
Photochemically Modulated Endothelial Cell Thrombogenicity via the Thrombomodulin/Tissue Factor Pathway
No full textPhotodynamic therapy (PDT) is based on a photochemical
reaction using a photosensitizer and light to produce reactive
oxygen species that have biological effects. Although its
application in some fields is largely based on thrombosis, in
the vascular setting thrombosis must be prevented. In this
study we examined the effects of PDT on the changes in
activity of thrombomodulin (TM) and tissue factor (TF) as
important regulators of the coagulation process of endothelial
cells. Human umbilical vein endothelial cells were treated with
PDT (chloro-aluminum-sulfonated phthalocyanine, k 5 630
nm) at different light-energy doses, and TM and TF levels
were measured using fluorescence spectroscopy. Microparticles
(MP) were analyzed using flow cytometry analysis. PDT
alters the thrombogenic state of endothelial cells by causing
decreased expression of TM and increased expression of
functional TF in a light-energy dose–dependent way. PDTtreated
endothelial cells shed large numbers of MP containing
high levels of TF. TF functionality of PDT-treated cells,
measured by a Factor Xa–generating assay, was high. TF was
located mostly intracellularly and in MP. The disturbed
anticoagulant balance described in this study may explain the
occurrence of thrombosis induced by PDT and, if not
contained, dispute the suitability of PDT as an adjuvant
modality to treat vascular restenosis
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