Intravitreal low molecular weight heparin in PVR surgery.

PURPOSE: To evaluate the efficacy of low molecular weight heparin (LMWH) in prevention of postoperative fibrin formation following vitreoretinal surgery with proliferative vitreoretinopathy (PVR). MATERIAL AND METHODS: Thirty consecutive patients of retinal detachment with advanced PVR were enrolled in the study. They were randomised to study and control groups (n = 15 each). Study group patients received vitreoretinal surgery with 5 IU/cc of LMWH in vitrectomy infusion fluid. The control group patients received vitroretinal surgery without heparin in the infusion fluid. Patients were followed up at 1 week, 1 month and 3 months after surgery. Postoperative bleeding, media clarity, best-corrected visual acuity and success of the surgery at the end of 3 months were compared between the two groups. RESULTS: At each follow-up visit, the study group showed a better media clarity, which was statistically significant (P = 0.0042). The study group had a 50% better chance of retinal reattachment compared to the control group. Five patients had intraoperative bleeding in the study group (33%) compared to 3 patients in the control group (20%). CONCLUSION: Use of intravitreal LMWH prevents postoperative fibrin formation and is beneficial in repair of retinal detachments with PVR.

Angiotensin II binding to human embryonic lung fibroblasts causes transient changes in cytosolic calcium and promotes fibrin gel contraction.

Contraction of granulation tissue is promoted by the peptide vasoconstrictor angiotensin II (AII), which presumably acts on the fibroblasts present in granulation tissue. Direct effects of AII on fibroblast contraction were examined using an in vitro fibrin gel contraction model. Fibrin gels were formed by mixing cultured human embryonic lung fibroblasts with fibrinogen, in the presence of thrombin and measurement of gel volume was used to determine the extent of fibrin gel contraction by fibroblasts. AII stimulated an additional 28.5 +/- 3% decrease in gel size after 24 hr, AII is also shown to specifically bind to human embryonic lung fibroblasts and stimulate rapid transient increases in cytosolic calcium. AII stimulates contraction of human embryonic lung fibroblasts as reflected by acceleration of fibrin gel contraction. Fibrin clot contraction contributes to extra cellular matrix reorganization during initial stages of wound repair and AII-stimulated fibroblast contraction may accelerate this process.

effect of clindamycin on the adherence of staphylococcus aureus to hydrocarbons and fibrin clots

The effect of clindamycin on the adherence of Staphylococcus aureus, replicating and non-replicating, to hydrocarbons and fibrin clots was studied. Staph. aureus adhered well in both model systems. Clindamycin inhibited adherence in both model systems when it was included in the assay media. Staph. aureus grown at 1/2 MIC of clindamycin also showed decreased adherence in both systems