New flexible endoscopic full-thickness suturing device: a triple-arm-bar suturing system.

BACKGROUND AND STUDY AIM: A reliable full-thickness suturing device is necessary for pure natural orifice transluminal endoscopic surgery (NOTES). The present study focused on assessing the reliability of a new suturing device. METHODS: A total of 60 single sutures were tested to close 5-cm incisions in 8-cm square pieces of resected swine stomach. Each incision was sutured by an over-the-scope clip (OTSC; n = 20), a single hand-sewn stitch (n = 20), or a single triple-arm-bar suturing system (TBSS) stitch. The maximum pulling force durability (MPD) of each suture was tested. To assess the reliability of the TBSS for endoscopic full-thickness resection (EFTR), 60 EFTRs of 50 mm diameter were performed on excised swine stomachs. After EFTR, full-thickness sutures were made using 3-stitch OTSCs (n = 20), 10-stitch hand-sewn sutures (n = 20), or 10-stitch TBSS sutures (n = 20). Outcomes were the MPD test for both single stitch and multiple stitch applications and the suturing time for single-stitch sutures. RESULTS: In the single-stitch MPD tests, there were significant differences between OTSCs and hand-sewn sutures (P = 0.0002) and between OTSCs and TBSS sutures (P = 0.0001), but no significant difference between hand-sewn and TBSS sutures. The multiple-stitch sutures revealed significant differences between OTSCs and hand-sewn sutures (P = 0.0039), and between OTSCs and TBSS sutures (P = 0.013). There was no significant difference between hand-sewn and TBSS sutures. There were significant differences in suture times between OTSC, hand-sewn sutures, and TBSS sutures (P < 0.05). CONCLUSIONS: Both single-stitch and multiple-stitch sutures using TBSS have similar strength to hand-sewn sutures. TBSS is a reliable suturing device.

Production of macromolecular activators of phagocytosis by lysed platelets.

Macromolecular activators of phagocytosis from platelets (MAPP: 1-MAPP and s-MAPP) are released from activated fresh platelets and enhance leukocyte phagocytosis via the Fcgamma receptors. In this study, production of MAPP was investigated in lysate of freeze-thawed stored platelets (PL). Incubation of PL and thrombin with precursors of MAPP (pre-MAPP: pre-1-MAPP and pre-s-MAPP) produced 1-MAPP and s-MAPP, whereas products released from stored platelets by stimulation with thrombin or collagen did not produce MAPP after incubation with pre-MAPP. The action of thrombin in MAPP formation with PL and pre-MAPP was inhibited by antithrombin III and heparin, and sequential incubation studies indicated that the key site of action of thrombin was on a component of PL. Other serine proteases such as trypsin could be substituted for thrombin in this reaction, whereas the action of thrombin was specific when whole platelets were used instead of PL. Gel filtration of PL before and after treatment with thrombin suggested that a macromolecule in PL (PMA-I) is digested by thrombin and liberates a 700 to 800 Da substance (PMA-II) which converts pre-MAPP to MAPP.

Effects of platelet release products on neutrophilic Fc gamma receptors.

Large and small macromolecular activators of phagocytosis from platelets (I-MAPP and s-MAPP, respectively), which function via the neutrophilic Fc gamma receptors (Fc gammaR) were refined from platelet release products by gel filtration and affinity chromatography with the use of an anti transferrin antibody column and the mechanism of phagocytosis activation was investigated. Flow cytometry revealed that 1-MAPP and s-MAPP did not increase the expression of neutrophilic Fc gammaRII (CD32) and Fc gammaRIII (CD16) antigens, whereas rosette formation of neutrophils with rabbit IgG-sensitized sheep erythrocytes (EA) in the presence of anti Fc gammaR antibodies suggested that both MAPPs increase the binding ability of Fc gammaRII. On the other hand, the enhancing effect of I-MAPP and s-MAPP on neutrophilic phagocytosis disappeared with the increase in phagocytosis by the phosphate-buffered saline control neutrophils when they were centrifuged with EA before incubation for phagocytosis. The enhanced phagocytosis, both by the two MAPPs and centrifugation, was canceled by treatment of the neutrophils with anti-CD32 Fab. The phagocytosis activatory effects of MAPP on neutrophils were canceled by anti-CD71 monoclonal antibody but not by transferrin.

A novel function of transferrin as a constituent of macromolecular activators of phagocytosis from platelets and their precursors.

Macromolecular activators of phagocytosis from platelets (MAPP:s-MAPP, 1500kDa and 1-MAPP, 300kDa) are glycoproteins released from human platelets and activate leukocyte phagocytosis via the Fc gamma receptors. Their production can be shown in CPD-stored platelets which have lost MAPP releasing activity by incubation with plasma-derived precursos of MAPP (pre-MAPP : pre-s-MAPP, 150kDa and pre-l-MAPP, 300kDa) in the presence of Ca++. Partial amino acid sequence analysis of s-MAPP revealed that it had homogeneity with transferrin (TF). Affinity chromatography using anti TF immunosorbent column showed that all of pre-MAPP and MAPP had immunoreactivity with anti TF antibodies. S-MAPP and 1-MAPP rich preparations from platelet release products lost their activity after treatment with ATP at acidic pH, in which condition iron atoms could be removed from holo-transferrin molecules. In the experiment using polymerized TF and stored platelets, it was shown that platelets incubated with dimer and tetramer TF could produce MAPP function. These results suggest that dimer and tetramer transferrin are precursors of s-MAPP and 1-MAPP, respectively and that iron atoms are necessary for their phagocytosis activating function.

Antibody mediated ligation of platelet/endothelial cell adhesion molecule-1 (PECAM-1) on neutrophils enhances adhesion to cultured human dermal microvascular endothelial cells.

We investigated the effects on leukocyte adhesion to cultured human dermal microvascular endothelial (DMvE) cell by antibody mediated ligation of platelet/endothelial cell adhesion molecule-1 (PECAM-1) on neutrophils. Preincubation of neutrophils with anti-PECAM-1 antibody markedly enhanced their adhesion to DMvE cells, while the adhesion-increasing action was cancelled out by anti-CR3 or anti-LFA-1 beta (CD18) antibody. These findings suggest that ligation of PECAM-1 on neutrophils increases their adhesion to cultured DMvE cells depending on the beta 2 integrin family, and PECAM-1 may have a crucial role in dermal inflammation.

Effects of released products from platelets on neutrophilic adhesion to endothelial cells and nylon fibers.

In this study, the effects of platelet release products (PRPr), ATP, and ADP on the adhesion of human neutrophils to human umbilical vein endothelial cells (HUVEC) and nylon fibers (NF) are described and the implications of various adhesion molecules are considered. Adhesion of neutrophils to HUVEC and NF was increased by PRPr, ATP, and ADP, while their adhesion-increasing actions were cancelled or considerably repressed by apyrase treatment. When anti-CD11a or anti-CD11b was added to neutrophils with PRPr, ATP, or ADP, the adhesion-increasing action was cancelled or considerably repressed. On the other hand, anti-ICAM-1 and anti-CD35 had no significant effects on this action. The above results indicated that platelets, through ATP and ADP in PRPr, increased the adhesion of neutrophils to endothelial cells and foreign bodies. Although it was suggested that the adhesion-increasing action was at least partially based on CD11a and CD11b, ICAM-1 and CD35 had no part in the enhancement of the adhesion.

Recovery of macromolecular activators of phagocytosis from platelets (MAPP) producing and releasing function in stored human platelets.

Macromolecular activators of phagocytosis from platelets (MAPP) were not released from platelets prepared from platelet concentrates (PC) obtained after anticoagulation with CPD solution and stored for more than 48 h. The MAPP activity which had escaped into the plasma disappeared after 72 h of storage. After incubation in dialyzed and Ca(2+)-supplemented plasma prepared from the same PC or from fresh peripheral blood, the platelets obtained after storage for 72 h released both MAPP (l-MAPP and s-MAPP) upon thrombin stimulation. Gel filtration studies of the plasma revealed that l-MAPP and s-MAPP were produced from the platelets incubated in plasma fractions corresponding to l-MAPP and s-MAPP, respectively. These observations suggest that platelets accumulate precursors of MAPP, pre-MAPP comprising pre-l-MAPP and pre-s-MAPP, in the presence of Ca2+, and produce and release MAPP when stimulated with thrombin.

Studies on macromolecular activators of phagocytosis from platelets (MAPPs) using anti MAPP murine monoclonal antibodies.

1-MAPP(290 kD) and s-MAPP(150 kD) are glycoproteins which have been shown to be involved in released products from platelets (PRPr) and to activate monocyte and neutrophil phagocytosis via the Fc receptors. Three IgG 2a (kappa) murine monoclonal antibodies against 1-MAPP and nine IgG1 (kappa) antibodies against s-MAPP have been raised. By affinity chromatography using these monoclonal antibodies, active MAPPs were obtained from the supernatant of outdated platelet concentrates in the presence of 60% saturated ammonium sulphate and from PRPr-rich medium, and substantial amounts of non-functioning immunoreactive MAPPs were obtained from the precipitate. Fab fragments of one of the two anti 1-MAPP and of two of the four anti s-MAPP monoclonal antibodies inhibited the function of their corresponding MAPPs, but none of them could inhibit the other MAPPs. 1-MAPP and s-MAPP in the platelets were visualized by indirect fluorescent antibody technique using Fab fragments of the antibodies.