Applications of hyaluronan in abdominal surgery. An experimental study

Contains fulltext : 90827.pdf (publisher's version ) (Open Access)9 september 2011Promotor : Bleichrodt, R.P. Co-promotores : Goor, H. van, Reijnen, M.M.P.J.177 p

Turning Oars 037

The Turning Oars collection features a series of photographs depicting the process of creating oars for Cape Kiwanda Wood Products of Pacific City by partners Paul Hanneman and Terry Learned. To look at the process chronologically, view the images in numerical order (Turning Oars 001 — Turning Oars 072). Terry Learned provided the description for this image. In this image, the cutter head continues down the track as described in Turning Oars 036.https://digitalcommons.linfield.edu/dory_archphotos_all/1099/thumbnail.jp

Influence of monocyte-like cells on the fibrinolytic activity of peritoneal mesothelial cells and the effect of sodium hyaluronate.

Contains fulltext : 48024.pdf (publisher's version ) (Closed access)OBJECTIVE: To determine whether the presence of cells of the monocyte-macrophage system affects the fibrinolytic response of peritoneal mesothelial cells to lipopolysaccharide (LPS) in the presence and absence of sodium hyaluronate. DESIGN: Controlled laboratory experiment. SETTING: Cell cultures in an academic laboratory research environment. PATIENT(S): Human peritoneal mesothelial cells were harvested from patients undergoing a laparotomy for noninfectious reasons and were cultured in vitro. Co-cultures were formed by adding U-937 human monocyte-like cells to a monolayer of mesothelial cells. INTERVENTION(S): After 24 hours, cultures were treated with 10 ng/mL of LPS, and sodium hyaluronate was added in a final concentration of 0.2%. Controls received medium without sodium hyaluronate. MAIN OUTCOME MEASURE(S): After 24 hours' incubation, tissue plasminogen activator (tPA), urokinase plasminogen activator (uPA), and plasminogen activator inhibitor-1 (PAI-1) levels were determined in medium and cell lysates by using ELISA techniques. RESULT(S): In medium of co-cultures, tPA and PAI-1 concentrations were statistically significantly increased compared with the case of monocultures, whereas uPA concentration was statistically significantly decreased. In cell lysates of co-cultures, PAI-1 concentration was statistically significantly increased compared with the case of monocultures, whereas tPA and uPA were unaffected. Treatment with sodium hyaluronate statistically significantly decreased PAI-1 and uPA concentrations in medium of monocultures but decreased uPA concentration only in medium of co-cultures, compared with the case of controls. CONCLUSION(S): Cells of the monocyte-macrophage system modulate the fibrinolytic capacity of LPS treated human peritoneal mesothelial cells and interfere in the hyaluronan-associated changes in mesothelial fibrinolytic capacity

Auto-cross-linked hyaluronic acid gel does not reduce intra-abdominal adhesions or abscess formation in a rat model of peritonitis.

Contains fulltext : 50830.pdf (publisher's version ) (Closed access)BACKGROUND: Prevention of adhesion and abscess formation would decrease mortality and morbidity after peritonitis. In this study the effect of a new anti-adhesive, auto-cross-linked hyaluronic acid polysaccharide (ACP) gel, on adhesion and abscess formation was studied in a rat peritonitis model. MATERIALS AND METHODS: In experiment 1, bacterial peritonitis was induced in 24 Wistar rats, using a cecal ligation and puncture model. Animals were randomized to receive 4 mL ACP gel (4%) or 4 mL phosphate buffered saline (PBS). After 2 weeks animals were killed and adhesions and abscesses were scored. In experiment 2, 72 rats underwent the same procedure but were randomized to receive 2 mL ACP gel, 4 mL ACP gel, or 4 mL PBS. After 1 and 3 weeks, respectively, half of the animals in each group were killed and adhesions and abscesses were scored. RESULTS: The median total adhesion score was 12 (range, 3-20) in the ACP group and was 9 (range, 6-12) in the PBS group (not significant) in experiment 1. 91% of rats in the ACP group developed abscesses, versus 90% in the control group. There were no significant differences in abscess size or number of abscesses. In experiment 2, total adhesion scores in the 2 mL ACP group, 4 mL ACP group, and PBS group were 4 (range, 2-20), 6 (range, 1-11), and 6 (range, 1-18), respectively, (not significant) after 1 week and 3.5 (range, 1-8), 5 (range, 2-15), and 4 (range, 0-9), respectively, (not significant) after 3 weeks. All rats in the 2 mL ACP group and the PBS group and 83% of the 4 mL ACP group had developed abscesses after 1 week. After 3 weeks these percentages were 80, 75, and 73, respectively. There were no significant differences in size or number of abscesses between groups both after 1 and 3 weeks. CONCLUSION: ACP does not reduce adhesion and abscess formation in a rat peritonitis model

Role of compression stockings after endovenous laser therapy for primary varicosis

Objective: The objective of this prospective, randomized trial was to evaluate the effect of compression stockings after endovenous laser therapy (EVLT) for insufficiency of the great saphenous vein. Effect evaluation was focused on differences in postoperative pain within 6 weeks. Methods: The study randomized 111 patients undergoing EVLT for duplex ultrasound confirmed great saphenous vein insufficiency (C(2-4)E(P)A(S)P(R)) to receive either 2 weeks of elastic stockings (class II, thigh length) or no elastic stockings after an initial 24-hour period of wearing bandages. Patients registered pain scores (primary outcome) and use of analgesics in a diary on a visual analog scale. At 2 days, 14 days, and 6 weeks after the procedure, leg circumferences, Aberdeen Varicose Vein Questionnaire scores, RAND 36-Item Health Survey scores, patient satisfaction (5-point scale), time before returning to work, and adverse events (secondary outcomes) were evaluated. Results: In the 79 patients (15 men and 64 women; mean age, 52 years) who completed the treatment and follow-up, small but significant differences in pain scores were observed during the first week after laser surgery, with more favorable scores in the group wearing stockings. Patients not wearing stockings used more analgesics than did patients wearing stockings (P <.05). Patients wearing stockings reported a statistically significantly higher score of satisfaction at 2 days (4.44 vs 4.15) and 6 weeks (4.59 vs 4.18), although the absolute differences were small. No significant differences were found regarding time to return to work, Aberdeen Varicose Vein Questionnaire scores, RAND 36-Item Health Survey scores, leg circumference measurements, and risk of complications. Conclusions: Wearing of postoperative stockings for 2 weeks after an initial 24-hour period of wearing bandages results in a small but significant reduction of postoperative pain and use of analgesics compared with not wearing compression stockings after EVLT for great saphenous vein insufficiency

Tc-99m-PEG-liposomes target both adhesions and abscesses and their reduction by hyaluronate in rats with fecal peritonitis.

Contains fulltext : 81407.pdf (publisher's version ) (Closed access)BACKGROUND: Abdominal adhesions and abscesses are a major source of morbidity and mortality after abdominal surgery and peritonitis. Adhesions are hard to detect with standard imaging techniques. Liposomes, coated with polyethylene glycol (PEG), represent an agent developed for infection imaging. This study investigated the capacity of 99mTc-PEG-liposomes to localize early adhesion formation after peritonitis. Additionally, the value of 99mTc-PEG-liposomes for therapy evaluation of hyaluronan solution, which reduces adhesion and abscess formation in experimental peritonitis, was assessed. METHODS: In 24 rats, a bacterial peritonitis was induced by performing a cecal ligation and puncture procedure. The animals were treated with sodium chloride solution or 0.4% hyaluronan solution intra-abdominally. One week later, scintigraphy was performed using 99mTc-PEG-liposomes, and abnormal focal uptake in the abdomen was scored. Thereafter, autopsy was performed and adhesions and abscesses were scored. RESULTS: A significant correlation was found between the total adhesion score and the scintigraphic score (P < 0.01, r = 0.65). Treatment with hyaluronan significantly reduced the total adhesion score (P = 0.01). The size of abscesses significantly correlated with the scintigraphic score (P < 0.01, r = 0.65). Treatment with hyaluronan reduced the size of abscesses (P < 0.05). CONCLUSION: 99mTc-PEG-liposomes are able to detect early adhesions and abscesses and may be used for therapy evaluation of agents that reduce adhesions and abscesses

Hyaluronan-based antiadhesive membrane has no major effect on intraperitoneal growth of colonic tumour cells.

Item does not contain fulltextBACKGROUND: A relationship between post-surgical adhesion formation and peritoneal tumour implantation has been proposed. Hyaluronan (HA)-based agents reduce adhesion formation, but the effect on peritoneal tumour is not established. This study investigated the influence of a HA-containing agent on intraperitoneal tumour in an experimental model. METHODS: 66 Balb/c mice underwent laparotomy and damage was inflicted to the parietal peritoneum. The animals were randomized into five groups. Groups 1 and 2 received HA-carboxymethylcellulose bioresorbable membrane and no treatment, respectively. Mice in groups 3-5 were injected intraperitoneally with 10(5) colon 26-B cells after the laparotomy. Treatment consisted of HA membrane, no HA agent and placement of HA membrane on the non-traumatized peritoneal wall, respectively. Animals were killed after 14 days; adhesions were scored in groups 1 and 2, and the tumour mass in groups 3-5. 45 Wag/Rij rats underwent the same procedures and treatment as mice in groups 3-5. In rats, 10(6) CC-531 cells were injected. Rats were killed after 3 weeks and the tumour mass was scored. Results: HA membrane resulted in a significant reduction of adhesions, but had no major effect on the intraperitoneal tumour mass in mice and rats. CONCLUSION: HA-carboxymethylcellulose bioresorbable membrane has no major effect on intraperitoneal tumour implantation and growth in an experimental model

Intercellular adhesion molecule-1 and gelatinase expression in human peritoneal mesothelial cells during propagation in culture.

Mesothelial cells are involved in a variety of biological processes, which include the formation of peritoneal adhesions. The cultures of human peritoneal mesothelial cells comprise an important tool to investigate the behavior and functions of mesothelial cells. Very little is known about the differences among mesothelial cells isolated from different sources and about the changes in specific functions as caused by cell propagation in vitro or that result from storage of cells at low temperatures. This study aims to characterize 2 particular cellular activities relevant for tissue repair, which include the expression of intercellular adhesion molecule-1 (ICAM-1) and the gelatinase activity; in addition, this study will assess the effect of hyaluronan, which is an antiadhesive agent, on these cellular activities. Viable cell lines were established from both omentum and peritoneal lavage fluid from 7 patients. Both ICAM-1 expression, which was measured by enzyme-linked immunosorbent assay (ELISA), and matrix metalloproteinase (MMP) bioactivity, which was measured by zymography, were measured in the 2nd and 4th passage; the latter also was measured after freezing and storing of cells in liquid nitrogen. The effects of interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), phorbol myristate acetate (PMA), and hyaluronan were analyzed. ICAM-1 was constitutively expressed and stimulated by IL-1beta, TNF-alpha, and PMA. All cell lines produced both MMP-2 and MMP-9. Only the latter activity was affected by TNF-alpha and, especially so, PMA. Differences were found between the 2nd and 4th passage, as well as between cells of different lineage, mostly so if the relative stimulation by the various agents was compared. The addition of sodium hyaluronate either to control cultures or to cultures together with any of the 3 stimuli examined did not significantly change either ICAM-1 expression or gelatinase activity. The freezing and storage of cells did not affect their functions. Both the human omentum and peritoneal lavage fluid are good sources to establish mesothelial cell lines, which can be propagated also after freezing without qualitative changes in their ability to express ICAM-1 and produce the gelatinases. For omental cells, a differential effect of stimulation occurs depending on whether the cells have been passaged 2 or 4 times. The presence of hyaluronan did not affect the expression of ICAM-1 or the gelatinases

Adhesion formation and reherniation differ between meshes used for abdominal wall reconstruction.

Item does not contain fulltextIncisional hernia is a common surgical problem, frequently requiring prosthetic mesh repair. The demands of the ideal mesh seem conflicting; ingrowth at the mesh-fascia interface, without development of adhesions at the visceral mesh surface. Various antiadhesives combined with macroporous mesh and composite meshes were studied for prevention of adhesions to mesh and ingrowth into the fascia. In 60 rats an abdominal wall defect was created and repaired with underlay mesh. Rats were divided into six groups and treated with polypropylene mesh (PPM, control), PPM with auto-cross-linked polymers (ACP) gel, PPM with fibrinogen glue (FG), polypropylene/expanded polytetrafluoroethylene (ePTFE) mesh, polypropylene/sodium hyaluronate/carboxymethylcellulose (HA/CMC) mesh, and polypropylene-collagen/polyethylene-glycol/glycerol (CPGG) mesh. Mesh infection was assessed in the postoperative period, adhesions and reherniations were scored at sacrifice 2 months after operation, and tensile strength of the mesh-tissue interface was measured. Six rats developed mesh infection, half of them were treated with PPM/ePTFE. The PPM/HA/CMC group showed a significant reduction in the amount and severity of adhesions. In animals treated with PPM/ACP and PPM/FG, severity of adhesions was reduced as well. Reherniation rate in the PPM/ACP group was 50% and significantly higher than that in other groups. Rats in the PPM/HA/CMC had the highest tensile strength. PPM/HA/CMC approaches the demands of the ideal mesh best, having superior antiadhesive properties, no reherniation and no infection in this rat model of incisional hernia