Vacuum sealing drainage as a pre-surgical adjunct in the treatment of complex (open) hand injuries: Report of 17 cases.

BACKGROUND: Few studies have been conducted to explore the use of the vacuum sealing drainage (VSD) technique in complex hand injuries. The aim of this study was to report outcomes in patients with complex hand injuries receiving VSD as a coadjuvant treatment prior to second-stage surgery. METHODS: This case series study retrospectively reviewed the patients who underwent VSD for treatment of hand injuries. Inclusion criteria for the study were: (1) traumatic soft tissue defects of the hand and wrist, accompanied by different degrees of injury and exposure of bone, tendon, or blood vessel; (2) the wound surface of hand and wrist was seriously contaminated and direct wound closure was not possible; and (3) the soft tissues of hand and wrist were seriously lacerated or avulsed, and showed necrosis or acute infection. After debridement, one-stage and/or two-stage repairs using healthy adjacent tissues were performed and the wound was covered by the VSD materials. The non-cytotoxic polyethylene alcohol hydration seaweed salt foam was applied during the VSD treatment for its good biocompatibility. The drainage tube was connected to the vacuum equipment and the negative pressures were set at -60kPa to -40kPa. The VSD device was left in place for 5 to 7 days before removal. Either free skin grafting or skin flap transplantation was used for wound closure and/or reconstructive surgery. The hand injury severity score was used to assess wound severity. The surgical results were scored using the total active motion classification. RESULTS: A total of 17 patients (13 and 4 patients had major and severe hand injuries), averaging 33.8 years were included. During the study period, 6 patients with severe hand injuries were not treated with VSD for the following reasons: (1) hemodynamic instability (n=1); (2) impaired coagulation function (n=1); (3) uncontrollable hemorrhage on the wound surface (n=2); and (4) exposure of the main blood vessels after surgical repair (n=2). VSD treatment was performed for an average of 7.4 days (range, 6-14 days) and the duration of wound healing averaged 23 days (range, 20-43 days). Wound infection was not reported prior to second-stage surgery. Only one of 17 patients had superficial necrosis at the flap edge, for a success rate of 94%. Average follow-up was 8.7 months (range, 4-13 months). Twelve (71%) patients reported excellent or good, four (23%) reported fair, and one (6%) reported poor results. CONCLUSION: The VSD can effectively promote safe and rapid repair of local soft tissues with good prognosis.

Intracellular oxidative stress induced by nitric oxide synthesis inhibition increases endothelial cell adhesion to neutrophils.

The objective of the present study was to determine whether prolonged inhibition of nitric oxide synthesis in endothelial cells increased the surface adhesion of these cells for neutrophils. Human umbilical vein endothelial cells (HUVECs) were grown to confluence in 48-well microtiter plates. Exposure of HUVECs to the nitric oxide synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME) did not cause neutrophil adhesion at 1 hour but increased adhesion at 4 hours in a dose-dependent manner. The increased adhesion was prevented with L-arginine or nitric oxide donors but not an analogue of cGMP. The increased adhesion was inhibited by monoclonal antibodies directed against the beta 2-integrin CD18 and endothelial cell adhesion molecule ICAM-1. Platelet-activating factor (PAF) receptor antagonist WEB 2086 also prevented the L-NAME-induced neutrophil adhesion. Intracellular oxygen radical scavengers (dimethyl sulfoxide, butylated hydroxytoluene, and alpha, alpha'-dipyridyl), the iron chelator desferrioxamine, and the mitochondrial inhibitor azide inhibited the L-NAME-induced neutrophil adhesion, whereas extracellular oxygen radical scavengers (superoxide dismutase and catalase) had no effect. HUVECs were loaded with 2',7'-dichlorodihydrofluorescein diacetate, and oxidation to the fluorescent dichlorodihydrofluorescein (DCHF) was monitored. Fluorescence was enhanced in the L-NAME-treated HUVECs throughout the 4-hour incubation, an event inhibitable by an antioxidant and azide. The magnitude of the intracellular oxidation of DCHF was equivalent to approximately 0.8 mumol/L H2O2. These data suggest that prolonged nitric oxide synthesis inhibition in HUVECs causes an oxidant- and PAF-associated rise in adhesion on the surface of these endothelial cells for neutrophils.

Nitric oxide inhibits numerous features of mast cell-induced inflammation.

BACKGROUND: We previously reported that mast cell degranulation causes histamine and P-selectin-dependent leukocyte rolling and platelet-activating factor (PAF)- and CD18-associated leukocyte adhesion, whereas others have reported serotonin-induced edema formation. The purpose of the present study was to determine whether nitric oxide (NO) could inhibit the mast cell-induced multistep recruitment of leukocytes and the associated microvascular dysfunction in single inflamed venules. METHODS AND RESULTS: Intravital fluorescence microscopy was used to demonstrate increased leukocyte rolling and adhesion and increased albumin extravasation in single 25- to 40-microns venules that were treated with the mast cell-degranulating agent compound 48/80 (CMP 48/80). The mast cell-induced histamine-dependent rolling and PAF-dependent adhesion were completely inhibited by the addition of the NO donor spermine NO. However, spermine NO did not directly inhibit histamine-induced leukocyte rolling and only partly affected PAF-induced leukocyte adhesion. Compound 48/80-activated mast cells evoked a significant increase in PAF-dependent neutrophil adhesion in vitro. Spermine-NO prevented the mast cell-dependent neutrophil adhesion but failed to affect direct adhesion with PAF. The mast cell-induced albumin leakage was also inhibited by the NO donor. CONCLUSIONS: Taken together, these results suggest that exogenous NO can modulate leukocyte recruitment and microvascular permeability alterations elicited by mast cell activation and raises the possibility that the use of NO donors may be a reasonable therapeutic approach to reducing mast cell-dependent inflammation.

A balance between nitric oxide and oxidants regulates mast cell-dependent neutrophil-endothelial cell interactions.

Nitric oxide (NO) synthesis inhibition causes neutrophil adhesion to endothelium via a mast cell- and oxidant-dependent mechanism. The objective of this study was to delineate the cascade of events in the mast cell- and oxidant-induced neutrophil-endothelium interactions after NO synthesis inhibition. Mast cells were isolated and purified from the rat peritoneal cavity and coadministered with neutrophils to wells of endothelium. This system was treated with an NO synthesis inhibitor (NG-nitro-L-arginine methyl ester; L-NAME) for 60 minutes. L-NAME did not induce neutrophil-endothelium interactions in the absence of mast cells, but the addition of mast cells in a ratio as low as 1:50 mast cells to neutrophils was sufficient to induce a large increase in neutrophil adhesion to endothelium within 20 to 25 minutes. L-arginine, NO donors, and 8-bromo-cGMP reversed the L-NAME effect, whereas NG-nitro-D-arginine methyl ester alone had no proadhesive effect. The adhesion was inhibited by an anti-CD18 or an anti-intracellular adhesion molecule-1 antibody and a platelet-activating factor-receptor antagonist. Inhibition of NO in isolated endothelial monolayers induced oxidant release (reduction of cytochrome C) into extracellular fluid. The endothelium-derived superoxide contributed to the mast cell-induced adhesion, inasmuch as the extracellular antioxidant superoxide dismutase reduced the neutrophil adhesion response as did disruption of endothelial function. There was some direct activation of mast cells with L-NAME (independent of endothelium) inasmuch as intracellular calcium and oxidative stress increased within mast cells after L-NAME treatment, and this translated into increased neutrophil adhesion to nonendothelial substrata. These data demonstrate that depletion of NO increases oxidative stress within mast cells and endothelium and together these events promote neutrophil adhesion within the vasculature.

Nitric oxide synthesis inhibition induces leukocyte adhesion via superoxide and mast cells.

Recent work has demonstrated that inhibition of nitric oxide production with various nitric oxide synthesis inhibitors (L-NAME, L-NMMA) initiate leukocyte adhesion to postcapillary venules. The objective of this study was to elucidate the mechanism (or mechanisms) that promote the L-NAME-induced leukocyte response. Intravital microscopy was used to examine 25-40 microns venules in the rat mesentery. Nitric oxide synthesis was inhibited with L-NAME and leukocyte adhesion was observed over the first 60 min. The fourfold increase in leukocyte adhesion was independent of alterations in venular red blood cell velocity. The adhesion was superoxide-mediated inasmuch as superoxide dismutase (SOD) abolished the rise in leukocyte adhesion associated with nitric oxide synthesis inhibition. Ketotifen, a mast cell stabilizer, also abolished the rise in leukocyte adhesion induced by L-NAME. Histology revealed that mast cell degranulation occurred only in animals treated with L-NAME but not in animals pretreated with SOD or ketotifen. This observation suggests that mast cells become activated in the absence of nitric oxide production and superoxide contributes to the mast cell activation. The L-NAME-induced leukocyte adhesion could be reproduced by infusing hypoxanthine/xanthine oxidase (a superoxide generating system) or compound 48/80 (an activator of mast cells) and both responses were attenuated by ketotifen. These data suggest that inhibition of nitric oxide synthesis results in a superoxide and mast cell-dependent leukocyte adhesion.

Mechanisms underlying acute mast cell-induced leukocyte rolling and adhesion in vivo.

It has been proposed that a primary detector mechanism for tissue infection or injury may be the mast cell that releases agents that recruit leukocytes to the appropriate site at risk. The objective of this study was to evaluate the early mechanisms involved in mast cell-induced leukocyte recruitment. We used intravital microscopy to visualize leukocyte-rolling flux and adhesion in single 25 to 40 microns venules in mesenteric preparations that were treated with the mast cell-degranulating agent, compound 48/80 (CMP 48/80). Superfusion of the rat mesentery with CMP 48/80 caused a dose-dependent rise in the number of rolling and adherent cells, events significantly reduced by: 1) mast cell stabilizers, ketotifen, or cromolyn, and 2) chronic treatment with CMP 48/80 to deplete mast cell constituents. The increase in leukocyte flux associated with CMP 48/80 was blocked by diphenhydramine (H1-receptor antagonist) and an anti-P-selectin Ab (PB1.3), but not by the 5-lipoxygenase inhibitor, MK 886. The reduction in the flux of rolling leukocytes translated into fewer adherent leukocytes with diphenhydramine or PB1.3. The CMP 48/80-induced rise in leukocyte adhesion, but not leukocyte flux, was reduced by the platelet-activating factor (PAF)-receptor antagonist (WEB 2086) and an anti-CD18 Ab (CL26). MK 886 did not prevent the increased leukocyte adhesion. In vitro data revealed that mast cell-derived PAF induced essentially all of the leukocyte adhesion to endothelium or protein-coated plastic. These data suggest that mast cell degranulation induces P-selectin-dependent leukocyte rolling and CD18-dependent leukocyte adhesion via histamine and PAF, respectively.

A novel beta 1-dependent adhesion pathway on neutrophils: a mechanism invoked by dihydrocytochalasin B or endothelial transmigration.

It is generally accepted that the beta 2-integrin is restricted to mononuclear leukocytes. The objective of this study was to determine whether neutrophils can also express beta 1-integrin (specifically alpha 4 beta 1) and whether this can support neutrophil adhesion to endothelial cells and to extracellular matrix. We stimulated neutrophils with dihydrocytochalasin B (DHCB) and various chemotactic stimuli and observed that chemotactic stimuli induced neutrophil adhesion via beta 2-integrin (CD18), whereas DHCB and either fMLP, PAF, or IL-8 induced adhesion to endothelium or protein-coated plastic that was not inhibitable by anti-CD18 antibody. beta 2-integrin-deficient cells, which did not respond to chemotactic stimuli alone, also adhered avidly in the presence of chemotactic stimuli and DHCB. The induced neutrophil adhesion was inhibited by antibody to beta 1- or alpha 4-integrin chains, but only if an anti-beta 2-integrin antibody was also present. Flow cytometry revealed increased expression of both beta 1 and alpha 4 in the presence of fMLP plus DHCB. Transendothelial migration of neutrophils induced by chemotactic stimuli alone also increased expression of beta 1 and alpha 4. Transmigration across deendothelialized membranes induced a similar beta 1 expression on neutrophils suggesting that events other than an endothelial signal elicited beta 1-integrin expression. Transmigration-induced beta 1-dependent expression translated into only modest adhesion to protein-coated plastic. These data suggest that both a pharmacological (DHCB) and a physiological (transmigration) stimulus can invoke expression of alpha 4 and beta 1 on human neutrophils to mediate adhesion.

A juxtacrine mechanism for neutrophil adhesion on platelets involves platelet-activating factor and a selectin-dependent activation process.

The aim of this study was to identify the molecular mechanisms involved in neutrophil adhesion to immobilized platelets with particular focus on the possible existence of a juxtacrine system for neutrophil-platelet interactions. Platelets were immobilized onto collagen (type I)-coated coverslips that were placed in a flow chamber and neutrophils were perfused across these confluent monolayers at a shear stress of 1 to 4 dynes/cm2. Neutrophils rolled, and a significant proportion (25% to 50%) adhered to platelet monolayers. P-selectin was expressed in very large quantities on the surface of platelets and mediated all of the rolling, whereas the beta2-integrin mediated firm adhesion. An activation mechanism for adhesion was necessary inasmuch as fixed neutrophils continued to roll on immobilized platelets, but did not adhere. Platelets adherent to collagen produced significant levels of platelet-activating factor (PAF). Accordingly, the firm adhesion of neutrophils to platelets was significantly inhibited by a PAF receptor antagonist (WEB 2086). Treatment of only the platelets with acetylhydrolase, which converts membrane-associated PAF to lyso-PAF, prevented 60% of the adhesion. These data suggest that PAF, on the surface of platelets, mediated a significant portion of the adhesive interaction. Addition of some selectin-binding carbohydrates (fucoidan or soluble SLEx analogs but not dextran sulfate) to the platelets caused rolling neutrophils to immediately adhere, an event that was not observed on histamine or thrombin-treated endothelium or P-selectin transfectants. These data support the view that a juxtacrine activation process exists on immobilized platelets for neutrophils. This process can be greatly enhanced on platelets and may involve a signaling mechanism through P-selectin.