Biologic degeneration of vein grafts after thrombotic occlusion: Thrombectomy within 3 days results in better indices of viability

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Biologic degeneration of vein grafts after thrombotic occlusion: thrombectomy within 3 days results in better indices of viability

AbstractObjectivesTo clarify the mechanism for poor patency of vein grafts after thrombectomy and the time limit for successful salvage operation, we investigated the time course of biologic degenerative changes in thrombosed vein grafts.Materials and methodsThe right femoral artery was replaced with a femoral vein graft in 25 mongrel dogs. After 3 months, grafts were explanted in 5 dogs (control grafts), and the remaining 20 dogs underwent femoral artery ligation to create a thrombosed graft. Of the 20 grafts, 5 were explanted at 3 days after ligation (group I-3) and 5 were explanted at 5 days after ligation (group I-5). Of the remaining 10 grafts, 5 underwent thrombectomy at 3 days after ligation (group II-3) and 5 underwent thrombectomy at 5 days after ligation, and were reimplanted into the left femoral artery, then explanted 28 days after reimplantation. The grafts were assessed with immunohistochemistry and prostaglandin (PG) I2 assay (6-keto-PGI1α).ResultsOf the 25 grafts, occlusion recurred in 3 in group II-5 within 28 days after reimplantation. There were significant differences between group I-5 and group I-3 or control grafts for percentage of areas positive for α-actin, total number of cells per field, and proliferating cell nuclear antigen (PCNA)–positive cells in layer of thickened intima and atrophied media (I/M), and for total cell and PCNA- positive cell numbers per field in the adventitia. Mean 6-ketoPGF1α was 40 ± 14.1 pg/mg/min in control dogs, 84 ± 18.9 pg/mg/min in group I-3, and 15.4 ± 7.7 pg/mg/min in group I-5, demonstrating a significant reduction in group I-5 (P = .009).ConclusionGraft wall cell viability and PGI2 production in thrombosed vein grafts are well preserved for up to 3 days. Therefore graft salvage operations no later than 3 days after thrombotic occlusion may provide acceptable long-term patency of salvaged grafts

Identification, evolution, and regulation of expression of Guinea pig trappin with an unusually long transglutaminase substrate domain

Trappins are found in human, bovine, hippopotamus, and members of the pig family, but not in rat and mouse. To clarify the evolution of the trappin genes and the functional significance of their products, we isolated the trappin gene in guinea pig, a species belonging to a rodent family distinct from rat and mouse. Guinea pig trappin was confirmed to encode the same domain structure as trappin, consisting of a signal sequence, an extra large transglutaminase substrate domain, and a whey acidic protein motif. Northern blot analysis and in situ hybridization histochemistry as well as immunohistochemistry demonstrated that guinea pig trappin is expressed solely in the secretory epithelium of the seminal vesicle and that its expression is androgen-dependent. We confirmed that guinea pig trappin is cross-linked by prostate transglutaminase and that the whey acidic protein motif derived from guinea pig trappin has an inhibitory activity against leukocyte elastase. Genome sequence analysis showed that guinea pig trappin belongs to the family of REST (rapidly evolving seminal vesicle transcribed) genes

Catalytic Synthesis of Saturated Oxygen Heterocycles by Hydrofunctionalization of Unactivated Olefins: Unprotected and Protected Strategies

A mild, general, and functional group tolerant intramolecular hydroalkoxylation and hydroacyloxylation of unactivated olefins using a Co­(salen) complex, an <i>N</i>-fluoropyridinium salt, and a disiloxane reagent is described. This reaction was carried out at room temperature and afforded five- and six-membered oxygen heterocyclic compounds, such as cyclic ethers and lactones. The Co complex was optimized for previously rare medium ring formation by hydrofunctionalization of unactivated olefins. The powerful Co catalyst system also enables the deprotective hydroalkoxylation of <i>O</i>-protected alkenyl alcohol and hydroacyloxylation of alkenyl ester to afford cyclic ethers and lactones directly. The substrate scope and mechanistic proof of deprotection were investigated. The experimental evidence supports the concerted transition state of the bond-forming step involving a cationic Co complex

Catalytic Synthesis of Saturated Oxygen Heterocycles by Hydrofunctionalization of Unactivated Olefins: Unprotected and Protected Strategies

A mild, general, and functional group tolerant intramolecular hydroalkoxylation and hydroacyloxylation of unactivated olefins using a Co­(salen) complex, an <i>N</i>-fluoropyridinium salt, and a disiloxane reagent is described. This reaction was carried out at room temperature and afforded five- and six-membered oxygen heterocyclic compounds, such as cyclic ethers and lactones. The Co complex was optimized for previously rare medium ring formation by hydrofunctionalization of unactivated olefins. The powerful Co catalyst system also enables the deprotective hydroalkoxylation of <i>O</i>-protected alkenyl alcohol and hydroacyloxylation of alkenyl ester to afford cyclic ethers and lactones directly. The substrate scope and mechanistic proof of deprotection were investigated. The experimental evidence supports the concerted transition state of the bond-forming step involving a cationic Co complex