In vivo administration of tolmetin in hyaluronic acid modulates protease levels in postsurgical macrophage-conditioned media.

Tolmetin sodium in a hyaluronic acid carrier (tolmetin-HA) was previously shown to reduce adhesion formation and alter the kinetics and levels of cellular influx into the peritoneal cavity after surgery. In this study, the effect of tolmetin-HA on the level of protease activity in macrophage-conditioned media was determined. The level of collagenase activity in macrophage-conditioned media was suppressed at 12 and 24 h after administration of tolmetin-HA. Alternatively, the peak level of elastase activity measured in macrophage-conditioned media was unchanged after tolmetin-HA treatment, but the kinetics of expression of maximal protease activity was delayed from 12 h in the control surgical rabbits to 24 h in tolmetin-HA-treated rabbits. Elevated plasminogen activator activity was detected in acid-treated conditioned media from the tolmetin-HA-treated rabbits when compared to control levels. However, no alteration in the level of plasminogen activator inhibitor activity was present in conditioned media of macrophages harvested from tolmetin-HA-treated rabbits compared to controls. These data suggest that tolmetin-HA treatment altered the levels of neutral protease activity secreted by postsurgical macrophages and may therefore elevate the fibrinolytic potential of the peritoneal cavity after surgery.     

A role of postsurgical macrophage activation by peritoneal injury]

At a site of peritoneal injury after abdominal surgery, macrophages are thought to be a principle type of inflammatory cells. Therefore, we determined the metabolic activities of postsurgical peritoneal exudate macrophages using standardized rabbit model. Rabbits underwent midline laparotomy followed by resection and reanastomosis of the ileum. At various days after surgery, peritoneal exudate macrophages were recovered from lavage fluid. Postsurgical Day-5 macrophages expressed significantly high potential to produce superoxide anion even without PMA stimulation compared to non-surgical control macrophages, although an activity of Day-10 macrophages was similar to control. The conditioned media from postsurgical Day-1 macrophage culture strongly inhibited urokinase type plasminogen activator (PA) and this plasminogen activator inhibitor (PAI) activities decreased following the extension of postsurgical time. Conversely, PA activities of macrophage-conditioned media decreased by day 1 and then gradually increased reaching control levels by day 10. Elastase activities of macrophage-conditioned media gradually decreased until postsurgical day 10. These data suggest that surgical injury activates postsurgical exudate macrophages. However, a time course of metabolic activities of these cells was dependent upon each secretory products. This differential secretion might express the stage of activation and differentiation of postsurgical macrophages. Moreover, postsurgical activated macrophages may control the tissue repair through a digestion of injured matrix and fibrinolytic process.     

Modulation of postsurgical macrophage function by early postsurgical polymorphonuclear leukocytes.

Surgical trauma to the peritoneum, in the absence of infection, elicits a rapid and transient influx of polymorphonuclear leukocytes (PMNs) into the peritoneal cavity prior to the accumulation of macrophages. The aim of this study was to characterize the effects of these PMNs on macrophage function in the early postsurgical period. Rabbits underwent intestinal reanastomosis and peritoneal exudate cells were collected at various times after surgery. Macrophage-enriched preparations were incubated with spent media from cultures of PMNs obtained at the corresponding times after surgery. Superoxide anion (O2-) release by macrophages in response to phorbol myristate acetate was determined by cytochrome c reduction. Fibrinolytic and protease inhibitory activities in macrophage-spent media were also evaluated. The release of O2- had already increased at 2 hr, reached peak levels at 6 hr, and decreased by 24 hr after surgery. Spent media from PMNs harvested 6 hr after surgery suppressed, whereas spent media from postsurgical 12- or 24-hr PMNs increased O2- release from macrophages harvested at 6 and 12 hr after surgery. PMN-spent media had no effect on the secretion of plasminogen activator (PA) from macrophages harvested within 12 hr after surgery. In contrast, PA activity in the spent media from macrophages harvested 24 hr after surgery was elevated after exposure to PMN-spent media. PA inhibitory activity was reduced in macrophage-spent media at 2 hr after surgery and increased by 24 hr, while PMN-spent media had no effect on the level of PA inhibitory activity. Thus, soluble factors secreted into the culture medium by PMNs modulate macrophage function as soon as 6-12 hr after surgery.     

Production of protease inhibitors by postsurgical macrophages

The deposition and lysis of fibrin are important processes in normal peritoneal healing. Since macrophages secrete a neutral plasminogen activator, we studied the production of plasminogen-dependent, fibrinolytic activity by postsurgical macrophages. Peritoneal exudate macrophages were collected from rabbits after resection and reanastomosis of their ileum. Intracellular plasminogen activator (PA) activity of resident (nonsurgical) macrophages was 8.4 +/- 1.8 milli-Plough units (mPU)/10(6) cells. Postsurgical Day 1 macrophages had significantly less activity (0.33 +/- 0.056 mPU/10(6) cells) compared to resident cells. Thereafter, the PA activity gradually increased and reached control levels by Postsurgical Day 7. The PA activity secreted by postsurgical macrophages into serum-free medium after 48 hr of culture was also determined. Conditioned medium from macrophages collected on Postoperative Days 1-5 exhibited less PA activity than buffer controls. PA activity was detected after acid treatment of the conditioned medium to remove acid-labile inhibitors. The activities of PA in acid-treated conditioned medium increased gradually and reached nonsurgical levels by Postsurgical Day 7. In spent medium from macrophages collected on Postsurgical Days 1-3, high levels of urokinase inhibitory activities were secreted; production gradually decreased during the later postoperative period. This inhibitory activity of macrophage-conditioned medium on urokinase-like PA activity was partially diminished by acidification of the media. These results support the hypothesis that macrophages in the postsurgical exudate may play an important role in the fibrinolytic process during peritoneal wound healing, perhaps through production and secretion of plasminogen activator as well as acid-labile and resistant protease inhibitors.     

Fibrinolytic capacity in peritoneal fluid after laparoscopic and conventional colorectal resection: data from a randomized controlled trial

Background A reduced peritoneal fibrinolytic capacity after surgery is currently accepted to be the main cause for postoperative adhesions. The aim of this prospective randomized trial was to determine the fibrinolytic activity in peritoneal fluid after laparoscopic as compared to conventional colorectal resection.Methods A randomized controlled trial in parallel with the multicenter trial Lapkon II was conducted. Peritoneal fluid was sampled via drain at 2, 8, and 24 h after elective laparoscopic (n=14; LAP) and conventional (n=16; CON) colorectal resections. Activities and concentrations of tissue plasminogen activator (t-PA), plasminogen activator inhibitor type-1 (PAI-1) and t-PA/PAI complex were determined in all specimen by ELISA kits.Results There was no difference in age, sex or body mass index between both groups. Postoperatively, t-PA activity decreased in both groups and was lower 2 h after closing the abdomen in the laparoscopic group (p<0.05). PAI-1 activity and concentration increased in both groups. Difference between the groups was measured for PAI-1 concentration after 24 h (p<0.05). There were no differences between the groups regarding t-PA concentrations, PAI-1 activity and t-PA/PAI complex.Conclusions After closing the abdominal cavity, postoperative changes in fibrinolytic capacity of peritoneal fluid can be determined in samples collected by a drain. However, there were no major differences in the postoperative course of fibrinolytic capacity in peritoneal fluid after laparoscopic and conventional colorectal resections.     

Normal saline induces oxidative stress in peritoneal mesothelial cells

Background

Peritoneal adhesions are the most common complication of the abdominal surgery. Normal saline is frequently used to rinse the peritoneal cavity during abdominal surgery, although there is no well-established data describing effect of such procedure on the process of formation of peritoneal adhesions.

Methods

Effect of 0.9% NaCl solution on viability, oxidative stress, and fibrinolytic activity of human peritoneal mesothelial cells maintained in in vitro culture was evaluated.

Results

Exposure of mesothelial cells to 0.9% NaCl induces oxidative stress, derangement of their structure with subsequent increased release of tissue factor (+75%) and plasminogen activator inhibitor-1 (+19%), and simultaneous suppression of tissue plasminogen activator release (−39%). In effect, ration tissue plasminogen activator/plasminogen activator inhibitor-1 was reduced in 0.9% NaCl-treated cells by 50%. Pretreatment of cells with precursor of glutathione synthesis: l-2-oxothiazolidine-4-carboxylic acid prevented these changes.

Conclusions

Oxidative stress in the peritoneal mesothelium caused by 0.9% NaCl activates their procoagulant activity and impairs fibrinolytic properties of these cells. These effects disqualify 0.9% NaCl as rinsing solution during abdominal surgery.     

Effects of omentectomy on the peritoneal fibrinolytic system

PURPOSE: Decreased fibrinolytic activity in the serosal surfaces of peritoneal tissue appears to be a major factor in the development of peritoneal fibrous adhesions. The omentum reduces peritoneal adhesion by creating a mechanical barrier and producing fibrinolytic factors. This experimental study was designed to investigate the effects of omentectomy on the peritoneal fibrinolytic system. METHODS: Thirty animals were assigned randomly to a control group or an omentectomy group. On postoperative day 10, peritoneal and blood samples were collected and adhesions were graded qualitatively. We measured the concentrations of serum and peritoneal tissue plasminogen activator, peritoneal plasminogen activator inhibitor-1, tissue plasminogen activator/plasminogen activator inhibitor complex, and hydroxyproline. RESULTS: Adhesions were significantly increased after omentectomy. Omentectomy also resulted in a reduction of both serum and tissue "tissue plasminogen activator" levels. On the other hand, an increment in "plasminogen activator inhibitor-1" levels was observed after omentectomy. There were no differences in "tissue plasminogen activator/plasminogen activator inhibitor" complex or "hydroxyproline" levels. CONCLUSION: Omentectomy reduced peritoneal fibrinolytic activity significantly and the peritoneal plasminogen activator system showed corruption that did not resolve with the rest of the peritoneal system after omentectomy.     

Modulation of postsurgical macrophage function by postsurgical polymorphonuclear leukocytes]

Rapid and transient influx of polymorphonuclear leukocytes (PMN) is observed prior to accumulation of macrophages after surgical trauma. Rabbits underwent intestinal reanastomosis and at various times peritoneal exudate cells were collected and separated using a Percoll gradient. Postsurgical macrophages were incubated with PMN spent media obtained from various postsurgical periods. Macrophage release of O2- had already increased at 2 hr after surgery, reached peak levels at 6 hr and decreased by 24 hr. PMN spent media from 6 hr postsurgical cells functioned as a suppressor, whereas 12 or 24 hr PMN spent media increased the O2- release from the macrophages harvested at 6 and 12 hr after surgery. Plasminogen activator (PA) activity in the macrophage spent medium was elevated at 24 hr after surgery by exposure to PMN spent media, however no effects were observed on macrophages harvested within 12 hr after surgery. PA inhibitory activity was reduced at 2 hr after surgery, and gradually increased, but no effects of PMN spent media on the PA inhibitory activity was observed. Thus, soluble factors secreted into the medium by PMN may modulate macrophage metabolism in stages as the macrophages differentiate and promote wound repair.     

Laparoscopic-type environment enhances mesothelial cell fibrinolytic activity in vitro via a down-regulation of plasminogen activator inhibitor-1 activity

BACKGROUND: Fewer intraperitoneal adhesions have been observed after laparoscopic surgery compared with conventional techniques. The aim of this study is to assess the effect of the pneumoperitoneum on mesothelial cell fibrinolytic activity by use of an in vitro model. METHODS: Human peritoneal mesothelial cells were seeded onto 24-well plates and incubated in carbon dioxide or helium at 5 mm Hg for 4 hours or standard culture conditions. Supernatant was removed for analysis at 0, 24, 48, and 72 hours after gas incubation and analyzed for plasminogen activator activity, total tissue plasminogen activator (tPA), and total plasminogen activator inhibitor-1 (PAI-1) concentrations by use of an enzyme-linked immunosorbent assay. The effect of different insufflation pressures (0, 7, and 14 mm Hg) was also examined. RESULTS: Enhanced plasminogen activator activity was observed at 48 hours and 72 hours from cells exposed to CO(2) (P<.04 each) and helium (P<.05 each) compared with control. This was associated with a decrease in PAI-1 concentrations at 48 and 72 hours in both the CO(2) and helium groups compared with control (P<.03 each, CO(2) vs control; and P<.04 each, helium vs control). No changes in tPA levels were observed. Changes in insufflation pressures did not affect plasminogen activator activity. CONCLUSIONS: These results suggest that incubation of human mesothelial cells with both CO(2) and helium in the absence of oxygen enhances mesothelial cell fibrinolytic activity because of a reduction in PAI-1 concentrations. These changes may participate in the observed reduction in adhesions after laparoscopic surgery relative to open surgery.     

Time course of peritoneal tissue plasminogen activator after experimental colonic surgery: effect of hyaluronan-based antiadhesive agents and bacterial peritonitis

BACKGROUND: This study assessed the peritoneal fibrinolytic response during the first week after colonic surgery in rats with and without bacterial peritonitis, and possible modulation of the response by two hyaluronan-based antiadhesive agents. METHODS: A colonic anastomosis was constructed in 90 male Wistar rats. Peritonitis was induced in another 108 rats and a colonic anastomosis was constructed after 24 h. Rats in both groups were randomized into an untreated group or one of two groups treated with hyaluronan-based agents. One-third of each group was killed at each of days 1, 3 and 7 after operation, and tissue plasminogen activator (tPA) antigen and activity were measured in peritoneal biopsies. RESULTS: One day after colonic surgery in normal rats, tPA antigen concentration was significantly (P < 0.005) increased, whereas tPA activity levels were normal. By day 3 after operation tPA antigen had returned to baseline values while tPA activity was significantly increased (P < 0.05). One day after inducing peritonitis tPA antigen was significantly increased (P < 0.001), while tPA activity was significantly reduced (P < 0.05). Three and seven days after colonic surgery in rats with peritonitis tPA activity was increased (P < 0.001) while tPA antigen had returned to baseline values. Neither of the hyaluronan-based agents affected peritoneal tPA antigen levels or activity after colonic surgery. CONCLUSION: Both abdominal surgery and infection caused an early increase in peritoneal tPA antigen levels, followed by an increase in tPA activity. Peritonitis severely depressed early tPA activity. Application of hyaluronan-based agents did not affect the peritoneal fibrinolytic response to surgery and/or infection.     

Response of visceral peritoneum to abdominal surgery

BACKGROUND: Postoperative adhesion formation has been associated with a reduced capacity to degrade fibrin within the peritoneal cavity. Peritoneal fibrinolytic capacity has been shown to decrease during the course of a surgical operation. The aim of this study was to investigate whether tissue-type plasminogen activator (tPA), a key fibrinolytic enzyme, is released into the peritoneal cavity during operation. METHODS: Fluid released from the serosal surface of the small bowel was collected in a plastic bag from 16 patients undergoing surgery. Intraoperative blood samples were also taken from seven patients. Concentrations of the fibrinolytic components tPA and urokinase plasminogen activator (uPA), tPA activity and plasminogen activator inhibitor type 1 (PAI-1) concentration were measured by enzyme-linked immunoabsorbent assay. RESULTS: Intraoperative tPA concentrations were significantly raised in the peritoneal fluid collected compared with peripheral blood levels (P = 0.008). This resulted in a significantly higher tPA activity in the fluid compared with blood (P = 0.001). However, neither uPA (P = 0.29) nor PAI-1 (P = 0.84) concentrations differed significantly in fluid compared with blood. CONCLUSION: These data suggest that tPA is rapidly released by the visceral peritoneum during abdominal surgery. The different concentrations in peripheral blood and peritoneum suggest that tPA is released from the peritoneum by an active process, and does not solely derive from leakage of plasma.     

The hemostatic effect of deacetylated chitin membrane on peritoneal injury in rabbit model

In this study, we determined the effect of 80% deacetylated chitin (DAC-80) membrane on postsurgical bleeding after visceral and parietal peritoneal abrasion. Japanese white rabbits underwent a midline laparotomy followed either by a bilateral peritoneal sidewall abrasion (4×4 cm) or an abrasion of liver surface (3×2 cm). The injured surface was then covered with a 0.2 mm thick DAC-80 membrane. On postsurgical day 2, the rabbits were sacrificed and the amounts of postsurgical bleeding was determined by quantitating the number of red blood cells recovered in 50 ml peritoneal lavage fluid. The DAC-80 membrane was found to reduce postsurgical bleeding after the abrasion of liver surface (treated with DAC-80 membrane: 2.9±0.8; control: 24.6±5.9×10⁸ cells/peritoneal cavity, P<0.005). This same hemostatic activity was not observed after application in the peritoneal sidewall abrasion model. We also measured plasminogen activator activity (PA) and urokinase inhibitory (PAI) activity in the spent culture media of macrophages recovered from the postsurgical peritoneal exudate. The DAC-80 membrane reduced the PA secretion from postsurgical macrophages after liver surface abrasion (treated with DAC-80: 2.8±0.7; control: 3.9±0.9 mPU/ml). The DAC-80 membrane also showed similar effects on PA secretion after peritoneal sidewall abrasion. No significant effects were found in the secretion of PAI by postsurgical macrophages in both surgical models.These findings suggest that the DAC-80 membrane may have hemostatic activity through the modulation of fibrinolytic activity of peritoneal exudative macrophages.     

Fibrinolytic responses of human peritoneal fluid in laparoscopic cholecystectomy: a prospective clinical study

Background The reduction in peritoneal fibrinolysis is believed to be the pathogenetic mechanism of adhesion formation. The general conclusion based on previous clinical and experimental studies is that laparoscopic procedures produce less adhesion formation. The association between this beneficial effect of laparoscopic cholecystectomy and peritoneal fibrinolytic changes is not clear. Therefore, the authors aimed to compare the effects of open and laparoscopic cholecystectomy on peritoneal fibrinolysis. For this purpose, fibrinolytic parameters in peritoneal fluid were investigated 24 h after laparoscopic and open cholecystectomies. Methods In a prospective clinical study, peritoneal fluid was sampled via a drain 24 h after laparoscopic (n = 10) and open (n = 9) cholecystectomies. Activities and concentrations of tissue plasminogen activator (tPA), plasminogen activator inhibitor type 1 (PAI-1), and tPA/PAI-1 complex were determined by enzyme-linked immunosorbent assay (ELISA) kits. Results In peritoneal fluids, tPA and tPA/PAI-1 complex concentrations were higher in the open cholecystectomy group (p = 0.009 and p < 0.001, respectively), but tPA activity and PAI-1 concentrations did not differ between the groups (p = 0.514 and p = 0.716, respectively). Conclusions Fibrinolytic changes in peritoneal fluid have several similarities in open and laparoscopic cholecystectomies with regard to tPA activity and PAI-1 levels. However, higher tPA levels after the open procedure probably are secondary to more intense tissue handling leading to mesothelial release of tPA.     

Effects of interleukin-1 (IL-1) on postsurgical macrophage secretion of protease and protease inhibitor activities.

Although peritoneal macrophages secrete a variety of inflammatory mediators and proteases during postsurgical repair of the peritoneum, regulation of this secretion is poorly understood. Here, the responsivity of peritoneal macrophages to interleukin-1 (IL-1) stimulation in vitro, measured by the secretion of protease and protease inhibitor activities, was evaluated as a function of postsurgical time. Macrophages were harvested at various times after peritoneal sidewall abrasion, isolated by discontinuous density centrifugation and cultured with varying concentrations of IL-1. IL-1 increased the secretion of plasminogen activator (PA) activity by peritoneal macrophages in a concentration-dependent manner on postsurgical Days 0, 3, 10, and 14. Macrophages harvested on postsurgical Day 1 after surgery responded only to high concentration of IL-1, while on Days 5 and 7 all doses of IL-1 stimulate PA. On Days 7, 10, and 14 after surgery, the secretion of PA activity (after acid treatment) by postsurgical macrophages was generally high and increased with IL-1 treatment. The level of PA activity after inactivation of acid labile inhibitors (PAI) also increased in a dose-dependent manner on Days 0, 3, and 5. Although Day 1 macrophages expressed the highest PAI activity of all groups, they had relatively low responsivity to IL-1 with regards to PAI secretion. The level of elastase activity by postsurgical macrophages was lowest on Day 1, highest on Day 7, and decreased thereafter. All concentrations of IL-1 inhibited elastase activity of macrophages on Day 7.(ABSTRACT TRUNCATED AT 250 WORDS)     

Peritoneal response to pneumoperitoneum and laparoscopic surgery

BACKGROUND: It is generally believed that laparoscopic surgery inflicts less trauma to the peritoneum than open surgery. Local peritoneal fibrinolysis is a critical factor in adhesion development. The objective was to investigate fibrinolytic changes in the peritoneum during laparoscopic and open surgery. METHODS: At laparotomy (n = 10) peritoneal biopsies were taken at opening of the abdomen and just before closure. At laparoscopy (n = 12) opening peritoneal biopsies were taken after carbon dioxide insufflation, and closure biopsies just before exsufflation. Tissue concentrations of tissue-type plasminogen activator (tPA), plasminogen activator inhibitor type 1 (PAI-1) and the resulting tPA activity were assayed. RESULTS: Concentrations of tPA in peritoneal tissue declined during operation in both groups, but significantly so only in the laparotomy group (- 53 per cent; P = 0.01). PAI-1 levels were higher in opening biopsies from the laparoscopy group (P = 0.004). There was an increase in PAI-1 concentration during laparotomy, but not during laparoscopy. At the end of the operation, there was no difference between the groups. The resulting tPA activity did not differ between groups at opening or closure. In both groups there was a significant decline during operation (laparotomy: - 59 per cent, P = 0.02; laparoscopy: - 63 per cent, P = 0.01). CONCLUSION: These findings indicate that the peritoneal response to open and laparoscopic surgery is similar. The initial rise in peritoneal PAI-1 concentration during laparoscopy suggests an adverse effect of carbon dioxide insufflation, which might affect peritoneal repair.     

Stimulation of PAI-1 in rabbit anti-GBM glomerulonephritis

SUMMARY: It has previously been shown in human disease and animal models of glomerulonephritis (GN) that fibrin deposition is associated with a net reduction of glomerular fibrinolytic activity as a result of reduced expression of plasminogen activators and increased expression of plasminogen activator inhibitor type 1 (PAI-1). Conditioned media (CM) prepared from cultured glomeruli of normal rabbits and rabbits 24 (Day 1) and 96 (Day 4) h after induction of anti-GBM GN were compared for their effects on the synthesis of fibrinolytic molecules in human endothelial cells (EC). Only CM from Day 4 GN rabbits showed PAI-1 protein stimulatory activity of up to 148% ( P <0.05; n = 3) above that of untreated EC. This was also seen at the mRNA level. Glomerulonephritis Day 4 CM showed significantly higher amounts of tumour necrosis factor (TNF) and thrombin and transforming growth factor-β (TGF-β) bioactivity in comparison to glomerular CM from normal rabbits. After high performance liquid chromatography (HPLC) of Day 4 GN CM, PAI-1 stimulatory activity was found to correlate with the presence of interleukin 1 (IL-1), TNF and TGF-β. These results suggest a correlation between severity of anti-GBM GN in a rabbit model, increased PAI-1 synthesis and increased expression of TNF and TGF-β. This may potentiate glomerular fibrin and extracellular matrix deposition in anti-GBM GN, leading to glomerular crescent formation and eventual renal failure.     

The effectiveness of a single intraperitoneal infusion of a neurokinin-1 receptor antagonist in reducing postoperative adhesion formation is time dependent

BACKGROUND: Current methods to prevent intraabdominal adhesions are not uniformly effective. We recently showed in rats that a neurokinin-1 receptor (NK-1R) antagonist is capable of reducing adhesion formation. To determine the clinical feasibility of using an NK-1R antagonist to reduce adhesions, this study examined the time dependence for the effectiveness of NK-1R antagonist administration and its effects on wound healing. METHODS: Adhesions were surgically induced in rats receiving a single intraperitoneal infusion of the NK-1R antagonist, CJ-12,255, during or 1, 5, 12, or 24 hours after surgery. Adhesion formation was assessed 7 days later. In a subset of animals, tissue plasminogen activator (tPA) activity, which is a measure of peritoneal fibrinolytic activity, was determined in peritoneal fluid 24 hours after surgery (48 hours for animals infused at 24 hours). The tPA activity was also determined in nonoperated animals 24 hours after peritoneal injection of the NK-1R antagonist. Colonic burst pressures were measured 7 days after creation of anastomoses in rats that were administered the antagonist at surgery. RESULTS: The NK-1R antagonist significantly reduced (P=.003) intraabdominal adhesions when administered during or 1 hour after surgery, only moderately reduced (P=.08) adhesions when administered at 5 hours, and had no effect at 12 or 24 hours. Peritoneal tPA activity was significantly increased (P<.05) in peritoneal fluid 24 hours after administration of the NK-1R antagonist regardless of the surgical procedure. The NK-1R antagonist did not alter colonic anastomotic healing. CONCLUSIONS: These data show that some of the events critical to adhesion formation occur within the first 5 hours following an abdominal operation in this model. The fact that the NK-1R antagonist does not impair colonic anastomotic healing enhances its usefulness as a therapeutic agent to inhibit adhesion formation.     

Fibrinolytic activity of in vitro cultivated human bladder cell lines

Summary Three human bladder carcinoma cell lines, T 24, RT 4, and MANO, a human bladder nonmalignant epithelial cell line, HCV-29, and a human lung fibroblast line, 460 Hl, were investigated for their ability to induce fibrinolytic, urokinase and plasmin inhibitory activities in cell culture, using serum-free medium, for up to 36 h. Generally, the non-malignant cell line and the fibroblast line had a greater ability to produce urokinase inhibitor than did the malignant cell lines. The amount produced varied greatly between cells and over the study period. A low concentration of plasminogen activator, immunologically identical with urokinase, and its accumulation in culture supernate were found with RT 4 after 12 h and 24 h cultivations, whereas no plasminogen activator was detected in all other cell lines for periods up to 36 h. No plasmin, non-specific protease or plasmin inhibitory activities were detected in any of the supernates from the cell lines.     

Changes in fibrinolytic activity during the course of a single hemodialysis session

Cardiopulmonary bypass, a form of extracorporeal circulation, markedly increases blood fibrinolytic activity. Accordingly, we measured the effect of hemodialysis, another form of extracorporeal circulation, on fibrinolytic activity in 13 patients with end stage renal disease during and after a single hemodialysis session. Total fibrinolytic activity on fibrin plates, which reflects plasminogen activator levels, was below normal prior to dialysis, rose well above normal at one hour, and then dropped gradually so that just prior to the end of a dialysis session it was still significantly elevated. Within 30 minutes of the end of dialysis, fibrinolytic activity fell rapidly, approaching predialysis levels. In contrast, 5 patients studied before and 3 hours into a peritoneal dialysis session showed no change in their subnormal levels of plasminogen activator. Plasminogen and alpha-2 antiplasmin levels did not change significantly during the course of hemodialysis. Thus, hemodialysis, but not peritoneal dialysis, transiently increases fibrinolytic activity without consuming plasminogen, a pattern consistent with the release of tissue type plasminogen activator.