Full-thickness skin grafts to reinforce the abdominal wall: a cross-sectional histological study comparing intra- and extraperitoneal onlay positions in mice.

INTRODUCTION: In the repair of complex abdominal wall hernia, there can be a strong preference to avoid synthetic or biological implants as reinforcement material. Autologous full-thickness skin grafts (FTSG) have shown promising results. However, there are few clinical data on the use of FTSG in an intraperitoneal position and rudimentary knowledge about postoperative histological appearance of tissue remodelling and repair. OBJECTIVE: To investigate the histological appearance of FTSG in the intraperitoneal onlay mesh (IPOM) position. METHODS: Isogeneic FTSG was positioned in the IPOM (10 mice) and the onlay position (10 mice). After eight weeks, tissues were harvested for histological analysis. Tissue structure, inflammation and cell survival were investigated with histological and immunohistochemical staining. RESULTS: Morphology was similar in both positions. Luciferase staining indicated both onlay and IPOM graft cell survival, with microvascular networks present. In both positions, FTSG showed ongoing tissue remodelling processes and cystic formations containing hair and epidermis. Low-grade acute phase and chronic inflammation were present. Integration was observed in 50% of the mice with similar appearances in IPOM and onlay grafts. CONCLUSION: FTSG is tolerated, with comparable results either inside or outside the abdominal cavity, and in line with historic histological evaluations. The results suggest further research on FTSG as a potential future reinforcement material in selected cases of complex abdominal wall hernia repair.

COVID-19 Cases and Transmission in 17 K-12 Schools - Wood County, Wisconsin, August 31-November 29, 2020.

The coronavirus disease 2019 (COVID-19) pandemic has disrupted in-person learning in the United States, with approximately one half of all students receiving online-only instruction since March 2020.* Discontinuation of in-person schooling can result in many hardships (1) and disproportionately affects families of lower socioeconomic status (2). Current evidence suggests that transmission of SARS-CoV-2, the virus that causes COVID-19, in kindergarten through grade 12 (K-12) schools might not significantly contribute to COVID-19 spread nationwide (3). During August 31-November 29, 2020, COVID-19 cases, spread, and compliance with mask use were investigated among 4,876 students and 654 staff members who participated in in-person learning in 17 K-12 schools in rural Wisconsin. School-attributable COVID-19 case rates were compared with rates in the surrounding community. School administration and public health officials provided information on COVID-19 cases within schools. During the study period, widespread community transmission was observed, with 7%-40% of COVID-19 tests having positive results. Masking was required for all students and staff members at all schools, and rate of reported student mask-wearing was high (>92%). COVID-19 case rates among students and staff members were lower (191 cases among 5,530 persons, or 3,453 cases per 100,000) than were those in the county overall (5,466 per 100,000). Among the 191 cases identified in students and staff members, one in 20 cases among students was linked to in-school transmission; no infections among staff members were found to have been acquired at school. These findings suggest that, with proper mitigation strategies, K-12 schools might be capable of opening for in-person learning with minimal in-school transmission of SARS-CoV-2.

Plasma MMP-1 Expression as a Prognostic Factor in Colon Cancer.

BACKGROUND: Matrix metalloproteinases (MMP) are involved in the local and distant invasiveness of colorectal cancer. This study investigates the prognostic value of circulating matrix metalloproteinase levels in patients with colon cancer. METHODS: A cohort of 152 patients was followed for more than 10 years. The correlation of plasma levels of MMP-1,-2, -7, -8, and -9 and survival was investigated. RESULTS: A high level of MMP-1 in circulating plasma was associated with a poorer prognosis in colon cancer (HR 2.0, 95% CI 1.1-3.9) in multivariate analysis regarding 5-year cancer-specific survival. This was further seen in regard of 10-year cancer-specific survival. CONCLUSIONS: Measurement of plasma MMP-1 concentration in patients planned for radical colon cancer surgery might be of importance when discussing prognosis and selection of patients for oncological treatment and postsurgery surveillance.

Evaluating full-thickness skin grafts in intraperitoneal onlay mesh position versus onlay position in mice.

BACKGROUND: Importance: Hernia surgery requires reinforcement material with few side effects when used in the intraperitoneal position. Autologous skin grafting may meet this requirement, but animal experiments are obligatory before being applied in humans. OBJECTIVE: To compare survival and effects of isogeneic full-thickness skin grafts in the intraperitoneal onlay mesh (IPOM) position in mice, with a control group using the onlay position. Primary end point was graft survival and secondary end point adhesion formation and inflammation through NF-κB activity. METHODS: Design: Intervention study with 8-week follow-up in accordance with ARRIVE criteria, performed between 2015 and 2016. SETTING: Animal laboratory. PARTICIPANTS: Transgenic C57BL/6 mice with isogeneic background were used. Recipients were female wild-type phenotype mice >3 mo (n = 24). Donors were male or female mice >7 mo, with phenotype-positive for the luciferase gene (n = 20) or positive for NF-κB-luciferase gene (n = 4). INTERVENTION: Full-thickness skin was grafted in the IPOM position and compared with grafts in the onlay position as controls. Survival was evaluated by regular longitudinal postoperative luminescence imaging over 8 wk. Adherence formation was evaluated macroscopically after sacrifice. Inflammation of full-thickness skin grafts in IPOM position of NF-κB mice was evaluated in four additional mice. Main outcome and measure: Survival of grafts, evaluated by luminescence. RESULTS: Ten animals received grafts in the IPOM position, and 10 in the onlay position as controls. Graft survival after 8 wk was 100% (20/20). Average luminescence at the end of the 8-week period was 999,597 flux (min 162,800, max 2,521,530) in the IPOM group (n = 10) and 769,708 flux (min 76,590, max 2,164,080) in the onlay control group (n = 10). No adhesions requiring sharp dissection (Jenkins' scale >2) were seen. Four animals with grafts in the IPOM position showed peak inflammation (NF-κB activity) 5 d after surgery subsiding toward the end of follow-up. CONCLUSIONS: Full-thickness skin survives as well in the IPOM position as in the onlay control position, and few adherences develop. Further studies are required to fully characterize the tissue remodeling and repair processes associated with IPOM skin grafting. The result is relevant in the search for alternative reinforcement materials to be used in complex hernia surgery in humans.

DNA alterations in Cd133+ and Cd133- tumour cells enriched from intra-operative human colon tumour biopsies.

BACKGROUND: Tumour stem cells are considered important to promote disease progression, recurrence and treatment resistance following chemotherapy in colon cancer. However, genomic analyses of colorectal cancer have mainly been performed on integrated tumour tissue consisting of several different cell types in addition to differentiated tumour cells. The purpose of the present study was to compare genomic alterations in two cell fractions enriched of CD133+ and CD133-/EpCAM+ cells, respectively, obtained from fresh intraoperative human tumour biopsies. METHODS: The tumour biopsies were fractionated into CD133+ and CD133-/EpCAM+ cells by immunomagnetic separation, confirmed by immunocytochemistry and Q-PCR. DNA were extracted and used for array comparative genome hybridization (aCGH) after whole genome amplification. Frozen tumour tissue biopsies were used for DNA/RNA extraction and Q-PCR analyses to check for DNA alterations detected in the cell fractions. RESULTS: The number and size of DNA alterations were equally distributed across the cell fractions; however, large deletions were detected on chromosome 1, 7 and 19 in CD133-/EpCAM+ cells. Deletions were frequent in both cell fractions and a deletion on chromosome 19p was confirmed in 90% of the patients. CONCLUSION: Isolation of enriched cells derived from tumour tissue revealed mainly genomic deletions, which were not observed in tumour tissue DNA analyses. CD133+ cells were genetically heterogeneous among patients without any defined profile compared to CD133-/EpCAM+ cells.

Levels of matrix metalloproteinases differ in plasma and serum - aspects regarding analysis of biological markers in cancer.

BACKGROUND: There are inconsistencies in the use of serum or plasma when analysing the matrix metalloproteinases (MMPs) as diagnostic or prognostic markers. The purpose of this study was to compare the concentration of MMP-1, -2, -7, -8, -9 and -13 in serum vs plasma samples. METHODS: Blood samples were obtained from sixty-five men and women. Samples were analysed for levels of MMPs in corresponding citrate plasma and serum. RESULTS: All MMPs expressed higher concentration in serum compared with plasma (P<0.01). There were no differences between genders. CONCLUSIONS: Present study demonstrated significant differences regarding concentrations of some MMPs using plasma vs serum. We conclude that future studies regarding MMPs as biological markers in cancer should consider the use of citrate plasma instead of serum.

Stress response and well-being after open, laparoscopic, and NOTES transgastric uterine horn resection in a randomized porcine model.

BACKGROUND: NOTES is believed to induce less surgical trauma than open and laparoscopic surgery. The degree of surgical trauma can be assessed by measuring serum levels of acute-phase proteins such as CRP and TNF-α. We conducted a prospective randomized survival trial in which the inflammatory responses after laparoscopic, open, and NOTES transgastric uterine horn resection were compared. The aim of this study was to investigate whether NOTES procedures induce less inflammatory response. METHODS: Thirty pigs were randomized into three groups to undergo open, laparoscopic, or transgastric uterine horn resection. Weight, body temperature, and postoperative recovery were recorded and venous blood samples were taken for analysis of CRP and TNF-α at different time points. Analyses of CRP and TNF-α were performed using pig-specific ELISA assays. RESULTS: Procedure time was significantly longer for NOTES [median = 121 min (range = 94-155)] compared with that for open surgery [median = 22 min (14-27)] and laparoscopy [median = 37 min (20-45)] (p < 0.0001). There was a nonsignificant tendency for shorter recovery time for the NOTES animals. Twenty-seven animals survived for 4 weeks. One animal in each group was euthanized prior to 4 weeks. All animals gained weight during the 4-week period with no significant differences. Only animals in the NOTES group showed a significant weight gain during the first postoperative week (p = 0.007). On postoperative day (POD) 1, CRP was significantly lower in the NOTES group compared with the open and laparoscopic groups (mean = 0.72 ± 0.22, 0.98 ± 0.26, and 0.97 ± 0.20, respectively; p = 0.048). The CRP levels were normalized on day 14. Throughout the study there were no significant changes in TNF-α levels in the laparoscopic and NOTES groups. At POD 3 the open surgery group showed significantly higher TNF-α levels than the other groups (p = 0.036). CONCLUSIONS: Despite the longer operating time, the transgastric NOTES approach seems to be less traumatic than open or laparoscopic uterine horn resection in this porcine model.

Thymidine phosphorylase expression is associated with time to progression in patients with metastatic colorectal cancer.

BACKGROUND: 5-Fluorouracil (5-FU) is the cornerstone of chemotherapeutic treatment for patients with colorectal cancer. The enzyme thymidine phosphorylase (TP) catalyzes the conversion of 5-FU to its active metabolite, 5-fluoro-2'-deoxyuridine. TP is expressed in tumour epithelial cells and stromal cells, particularly in tumour-associated macrophages. These macrophages may affect sensitivity to chemotherapy. Previously, we identified TP as a predictive factor in microdissected tumour samples of patients with advanced colorectal cancer. In the present study, we analysed TP expression in tissues and associated stromal cells from patients with advanced colorectal cancer and associated TP levels to tumour response and time-to-event variables during first-line chemotherapy treatment. We also investigated the association between serum TP levels at the time of surgery and gene expression in primary tumour tissues. METHODS: This study included 125 patients with metastatic colorectal cancer treated with first-line 5-FU-based chemotherapy. To quantify TP gene expression levels in tumour tissues, real-time polymerase chain reaction was performed using the 7500 Fast Real-Time PCR system (Applied Biosystems, Foster City, CA, USA). TP protein concentration in matched serum samples was determined using an enzyme-linked immunosorbent assay system (USCN Life Science Inc.). RESULTS: The tumour response rate was 31%, and 30% of patients exhibited stable disease. No associations between TP expression level and age or gender were observed. Levels of TP mRNA in mucosa and tumours were positively correlated (r = 0.41, p < 0.01). No correlation between TP expression and tumour response rate was observed. Time to progression was significantly longer in patients with high TP expression (p < 0.01). Serum TP protein levels were not associated with tumour response or time-to-event variables and did not correlate with gene expression in tumour tissues. CONCLUSIONS: High TP gene expression in non-microdissected tumour tissues of patients with advanced colorectal cancer correlates with longer time to progression, which could be related to treatment. These results are in contrast to previous studies where microdissected tumour cells were analysed and may be due to the presence of adjacent stromal cells. Serum TP protein expression does not correlate to TP gene expression in tissues of patients with advanced colorectal cancer.

Omitting transesophageal echocardiography before catheter ablation of atrial fibrillation.

BACKGROUND: Data about necessity of performing transesophageal echocardiography (TOE) prior to every catheter ablation (CA) of atrial fibrillation (AF) is scarce. We aimed to evaluate the safety of an individualized risk-based approach to TOE with respect to thromboembolic cerebrovascular events (CVE) in patients undergoing CA for AF or left atrial tachycardia (AT). METHODS: We performed a retrospective clinical study based on our institutional registry database. Patients undergoing CA for AF or left-sided AT following initial AF ablation at two participating centers were enrolled. Prior to the procedure, patients were scheduled for TOE only if they had a history of thromboembolic stroke, left atrial appendage (LAA) thrombus, or inappropriate anticoagulation regimen in the previous 3 to 4 weeks. The incidence of periprocedural cerebrovascular thromboembolic events was assessed. RESULTS: We analyzed 1155 patients (median age 70 years, 54.8% male, 48.1% had persistent AF/AT). In 261 patients, a TOE was performed; in 2 patients (0.7%), an LAA thrombus was detected, which led to cancellation of the catheter ablation; in 894 patients, the TOE was omitted. Of the 1153 (0.35%) patients who underwent ablation, 4 (0.35%) experienced a CVE (one TIA and three strokes). The rate of CVE in our study does not exceed that reported in most multicenter trials. The low event rates limited statistical analysis of possible risk factors for CVE. In all 4 patients with CVE, post-CVE imaging showed the absence of LAA thrombus. CONCLUSIONS: An individualized selective approach to TOE before catheter ablation of AF or left AT showed a very low risk of overt intraprocedural thromboembolic events for the population in our study. A further randomized controlled study is needed to determine whether TOE prior to catheter ablation without ICE could be omitted in patients with uninterrupted OAC without previous thromboembolic events or a history of left atrial thrombus.

Intestinal mucosal MMP-1 - a prognostic factor in colon cancer.

OBJECTIVE: There is evidence that transforming growth factor-ß1 (TGF-ß1) and matrix metalloproteinases (MMPs) play an important role in tumor invasion and progression in colorectal cancer. The aim of this study was to assess their utility in prediction of cancer-specific survival (CSS). MATERIALS AND METHODS: 136 patients undergoing curative surgery for colorectal carcinoma were prospectively included. Samples were taken from tumor and tumor-free intestinal mucosa and ELISA was used to assess protein levels in the tissues. Patients were followed for CSS. The median follow-up time for all included patients was 65 months (range: 45-92). The main outcome measure was CSS. RESULTS: T stage, lymph node involvement and high levels of MMP-1 as well as MMP-9 in tumor-free mucosa tissue were significantly associated with CSS in colon cancer in univariate analysis. This prognostic strength was maintained for MMP-1 and N-status in multivariate analysis. CONCLUSIONS: The results indicate that MMP-1 is independently associated with CSS in patients with colon cancer. Furthermore, a possible clinical implication is that MMP-1 protein expression in tumor-free mucosa could identify colon cancer patients with poor CSS in need of more intensified adjuvant treatment.

COVID-19 Surveillance Testing in Secondary Schools: Findings and Barriers to Implementation.

PROBLEM CONSIDERED: K-12 schools have shown minimal spread of COVID-19 when mitigation measures are employed. This study sought to determine baseline asymptomatic COVID-19 rates in secondary schools as students returned to full-time in-person learning with universal masking in place and to evaluate the logistical obstacles of implementing surveillance testing. METHODS: An observational cohort study lasting 11 weeks during spring 2021 included 2,288 students and staff in Wood County, Wisconsin. SARS-CoV-2 nasal polymerase chain reaction testing was done on consenting students and staff to determine baseline disease burden. Teacher surveys collected data on student masking compliance and classroom distancing. Information about percent positivity, secondary transmission, quarantine and distancing policies, screening participation, costs, and volunteer hour requirements were obtained. Modified quarantine for fully masked in-classroom exposures was evaluated. RESULTS: Percent positivity averaged 3.0% (0%-16.2% weekly) among students and 1.72% (0%-6.9% weekly) among staff. Two cases of secondary transmission were suspected out of 163 individuals quarantined. An average of 15.6% of the school population consented to participate each week. Minimum classroom distance between students ranged from 2.7 to 5.5 feet. Student masking compliance was greater than 87%. The cost of the program was $106,400 and required approximately 300 volunteer hours. The modified quarantine policy, where students were allowed to continue to attend in-person school after exposure to a case of COVID-19 if the infected and exposed parties were masking, did not result in additional transmission. CONCLUSIONS: In the setting of relatively high student masking compliance and limited distance between students, weekly secondary school screening of students and staff in an area of high community disease spread was found to be low yield, costly, and burdensome for the school district. Surveillance participation was low. A modified quarantine policy was not associated with increased in-school transmission. School funding may be better spent on targeted testing or other school expenses, especially with increasing vaccination rates.

Tissue proteolysis in appendicitis with perforation.

BACKGROUND: Matrix metalloproteinases (MMPs) and serine proteases are able to degrade the extracellular matrix (ECM) and modulate immune responses in the gastrointestinal tract. The purpose of this study was to investigate local proteolysis in perforated appendicitis and its association with the appendix perforation. MATERIALS AND METHODS: Biopsies were taken at the sites of perforation (n = 15) and with a gradually increased distance from it. The expression and distribution of MMP-1, -2, and -9, the tissue inhibitor of metalloproteinases type (TIMP-1), plasminogen activator inhibitor type1 (PAI-1), and urokinase plasminogen activator (uPA) were measured by ELISA. The distribution of MMP-9, TIMP-1, uPA, and PAI-1 in perforated, nonperforated, and uninflamed appendix was investigated by immunohistochemistry with monoclonal antibody technique. RESULTS: MMP-1 expression was highest close to the perforation and was gradually decreased in biopsies in more distal locations (P < 0.01). MMP-9 showed a similar pattern being highest at the sites of perforation (P < 0.05), while MMP-2 expression showed a trend in the opposite direction without statistically significance. The expression of TIMP-1 trended lower at the sites of perforation. PAI-1 was highest at the sites of perforation (P < 0.01) and the uPA expression was similarly elevated close to and at the perforation. CONCLUSIONS: These data indicate a key role of MMP in the pathogenesis of appendix perforation. A local imbalance between MMP-9 and the inhibitor TIMP-1 could potentially contribute to the tissue injury leading to an appendix perforation. The overexpression of PAI-1 at the sites of perforation may also contribute to tissue damage.

Empowerment in the perioperative dialog.

Aim: To describe how the nurse anaesthetist empowers the patient in the perioperative dialogue. Design: A qualitative descriptive design with interviews with 12 nurse anaesthetist (NA). Method: A hermeneutic text interpretation with a foundation in Gibson's empowerment model. Result: The results highlight Gibson's nursing domain: Helper, Supporter, Counsellor, Educator, Resource Consultant, Resource Mobilizer, Facilitator, Enabler and Advocate. The overall understanding is revealed as a relationship can be built through closeness between the patient and the NA. The NA helps the patient master the situation by talking to and touching the patient. The patient is helped to find their own strengths and to cope with their fears. The patients decide over their own bodies. When the patients do not want to or cope with protecting themselves, the NA protects and represents the patient.

Cryopreservation of Whole Tumor Biopsies from Rectal Cancer Patients Enable Phenotypic and In Vitro Functional Evaluation of Tumor-Infiltrating T Cells.

TILs comprise functionally distinct conventional and unconventional T cell subsets and their role in responses to CRC treatments is poorly understood. We explored recovery of viable TILs from cryopreserved tumor biopsies of (chemo)-radiated patients with rectal cancer to establish a platform for retrospective TIL analyses of frozen tumors from pre-selected study cohorts. Frequencies of TIL subsets and their capacity to mount IFN-γ responses in cell suspensions of fresh vs. cryopreserved portions of the same tumor biopsies were determined for platform validation. The percentages and proportions of CD4+ TILs and CD8+ cytotoxic T lymphocytes (CTLs) among total TILs were not affected by cryopreservation. While recovery of unconventional γδ T cells and mucosal-associated invariant T cells (MAIT cells) was stable after cryopreservation, the regulatory T cells (Tregs) were reduced, but in sufficient yields for quantification. IFN-γ production by in vitro-stimulated CD4+ TILs, CTLs, γδ T cells, and MAIT cells were proportionally similar in fresh and cryopreserved tumor portions, albeit the latter displayed lower levels. Thus, the proposed platform intended for TIL analyses on cryopreserved tumor biobank biopsies holds promises for studies linking the quantity and quality of TIL subsets with specific clinical outcome after CRC treatment.

Long-term clinical experience with cardiac contractility modulation therapy delivered by the Optimizer Smart system.

AIMS: We assessed long-term effects of cardiac contractility modulation delivered by the Optimizer Smart system on quality of life, left ventricular ejection fraction (LVEF), mortality and heart failure and cardiovascular hospitalizations. METHODS AND RESULTS: CCM-REG is a prospective registry study including 503 patients from 51 European centres. Effects were evaluated in three terciles of LVEF (≤25%, 26-34% and ≥35%) and in patients with atrial fibrillation (AF) and normal sinus rhythm (NSR). Hospitalization rates were compared using a chi-square test. Changes in functional parameters of New York Heart Association (NYHA) class, Minnesota Living with Heart Failure Questionnaire (MLWHFQ) and LVEF were assessed with Wilcoxon signed-rank test, and event-free survival by Kaplan-Meier analysis. For the entire cohort and each subgroup, NYHA class and MLWHFQ improved at 6, 12, 18 and 24 months (P < 0.0001). At 24 months, NYHA class, MLWHFQ and LVEF showed an average improvement of 0.6 ± 0.7, 10 ± 21 and 5.6 ± 8.4%, respectively (all P < 0.001). LVEF improved in the entire cohort and in the LVEF ≤25% subgroup with AF and NSR. In the overall cohort, heart failure hospitalizations decreased from 0.74 [95% confidence interval (CI) 0.66-0.82] prior to enrolment to 0.25 (95% CI 0.21-0.28) events per patient-year during 2-year follow-up (P < 0.0001). Cardiovascular hospitalizations decreased from 1.04 (95% CI 0.95-1.13) events per patient-year prior to enrolment to 0.39 (95% CI 0.35-0.44) events per patient-year during 2-year follow-up (P < 0.0001). Similar reductions of hospitalization rates were observed in the LVEF, AF and NSR subgroups. Estimated survival was significantly better than predicted by MAGGIC at 1 and 3 years in the entire cohort and in the LVEF 26-34% and ≥35% subgroups. CONCLUSIONS: Cardiac contractility modulation therapy improved functional status, quality of life, LVEF and, compared to patients' prior history, reduced heart failure hospitalization rates. Survival at 1 and 3 years was significantly better than predicted by the MAGGIC risk score.

Differential prognostic impact of uPA and PAI-1 in colon and rectal cancer.

BACKGROUND AND OBJECTIVES: Degradation of extracellular matrix is important for tumour growth and invasion, which in part is regulated by the plasminogen activation system. The aim of the study was to evaluate the protein expression of urokinase plasminogen activator (uPA) and plasminogen-activating inhibitor-1 (PAI-1) in plasma, tumour-free mucosa and tumour tissue regarding their prognostic value in colon and rectal cancer. METHODS: Patients (n = 221) undergoing surgery for colorectal cancer were prospectively included. Samples were assayed by ELISA technique. RESULTS: PAI-1 in tumour tissue (p = 0.006), plasma (<0.0001) and uPA in tumour-free mucosa (p = 0.006) were associated with survival in rectal cancer in univariate analysis. An uPA expression level below 1.1 ng/mg (log rank test, p < 0.0001) in tumour-free mucosa was associated with poor survival in rectal cancer. This was true also for patients without disseminated disease (M(0), p = 0.02). PAI-1 in plasma correlated with metastatic disease (p < 0.0001). uPA and PAI-1 were not associated with survival in either tumour tissue, mucosa or plasma in patients with colon cancer. CONCLUSIONS: uPA and PAI-1 have a differential prognostic impact in colon and rectal cancer. Preoperative mucosal uPA and plasma PAI-1 protein expression could possibly be used as prognostic factors in rectal cancer.

uPA and PAI-1 in rectal cancer--relationship to radiotherapy and clinical outcome.

BACKGROUND: It is well known that the fibrinolytic system is of importance in inflammation, wound healing, and fibrosis development. However, it is also important in the process of tumor invasion and metastasis. We have investigated protein levels of urokinase plasminogen activator (uPA) and plasminogen activator inhibitor-1 (PAI-1) in rectal cancer and effects of radiotherapy, links to clinical outcome, and potential use as prognostic factors. MATERIALS AND METHODS: Ninety-one patients with rectal cancer were studied. Blood samples and biopsies were taken during surgery and assayed with enzyme-linked immunosorbent assay for uPA and PAI-1, and patients were followed prospectively (0-96 mo). RESULTS: Higher levels of uPA (P < 0.0001) and PAI-1 (P < 0.0001) were found in tumor compared with mucosa. Mucosa exposed to radiotherapy had higher levels of uPA (P < 0.0001) and of PAI-1 (P < 0.0001). Irradiated tumor tissue had higher levels of PAI-1 (P < 0.001). PAI-1 in tumor was correlated with T stage (P < 0.001) and N stage (P < 0.01). PAI-1 in plasma was higher in patients with synchronous distant metastases (P < 0.001). Cox regression was used to identify high levels of PAI-1 in tumor as an independent factor related to short disease-free survival (P < 0.01) and the ratio of uPA/PAI-1 to development of metastases (P < 0.01). CONCLUSIONS: There is a relationship between PAI-1 in plasma and rectal cancer metastases. PAI-1 in tumor tissue is correlated to histopathological data and to outcome of rectal cancer. If these findings can be confirmed in larger trials, there will be a possibility to use PAI-1 as a prognostic factor.

Studies of TGF-beta(1-3) in serosal fluid during abdominal surgery and their effect on in vitro human mesothelial cell proliferation.

BACKGROUND: Increased transforming growth factor-beta (TGF-beta) levels are associated with fibrosis, affected cell proliferation, and postsurgical adhesion development, but the knowledge regarding TGF-beta response to the surgical trauma is limited. This study investigated TGF-beta(1-3) isoforms and fibrinolytical factors in peritoneal serosal fluid during abdominal surgery, together with the in vitro effect of TGF-beta(1-3) on human mesothelial cell proliferation. MATERIALS AND METHODS: Total as well as biologically active TGF-beta(1-3) and fibrinolytic factors: t-PA, uPA, and PAI-1 were measured in serosal fluid and plasma from 23 patients undergoing colorectal cancer surgery. In vitro proliferation of human primary mesothelial cell cultures upon TGF-beta(1-3) stimulation was also investigated. RESULTS: Total TGF-beta1 and TGF-beta2 levels were similar in serosal fluid and plasma while active fractions were increased in serosal fluid. In contrast, total fraction of TGF-beta3 was higher in serosal fluid compared with plasma, while levels of active fractions did not differ. Plasminogen activators (t-PA, uPA) were elevated while the inhibitor (PAI-1) was decreased in serosal fluid compared with plasma. The in vitro mesothelial cell proliferation studies revealed that high TGF-beta(1-3) concentrations decreased cell proliferation, while lower concentrations of TGF-beta1 increased mesothelial cell proliferation. CONCLUSIONS: This human study shows increased active TGF-beta levels in peritoneal serosal fluid, compared with plasma, during abdominal surgery and that TGF-beta1 at physiological concentrations increased human mesothelial cell proliferation in vitro. TGF-beta cytokines may be involved in postsurgical adhesion formation.

Decreased peritoneal tissue plasminogen activator during prolonged laparoscopic surgery.

BACKGROUND: Peritoneal fibrinolysis is crucial in the peritoneal healing processes and subsequent adhesion formation. During conventional surgery, the peritoneal fibrinolytic system is rapidly disturbed. Short-term laparoscopy does not seem to affect peritoneal fibrinolysis. The aim of the present study was to assess the effect of prolonged laparoscopic surgery on peritoneal fibrinolysis. METHODS: Twelve consecutive patients undergoing laparoscopic gastric bypass surgery for morbid obesity were included in the study. During the procedure, biopsies of the parietal peritoneum were taken at the start of the procedure and each 45 min afterward. Tissue samples were homogenized and tissue-type plasminogen activator (tPA) antigen, tPA activity, urokinase-type PA antigen, and plasminogen activating inhibitors type 1 antigen were measured using commercial assay techniques. RESULTS: Both tPA antigen and its activity progressively decreased during the procedure, reaching significant levels after 90 min of surgery. The levels of uPA antigen and plasminogen activating inhibitors antigen did not significantly change throughout the procedure. CONCLUSIONS: As for conventional surgery, prolonged laparoscopic surgery causes a decreased fibrinolytic activity in the peritoneum due to decreased tPA levels.

Progress of tissue injury in appendicitis involves the serine proteases uPA and PAI-1.

OBJECTIVE: Serine proteases and the matrix metalloproteinases (MMPs) are key factors in the proteolytic cascade and participate in extracellular matrix (ECM) degradation. Fibrinolytic activators and inhibitors may have an effect on inflammatory cells, thereby modulating the inflammatory response. It is reasonable to assume that they may be implicated in the tissue injury in acute appendicitis that subsequently leads to appendix perforation. The purpose of this study was to investigate the expression and distribution of urokinase-type plasminogen activator (uPA) and plasminogen-activator inhibitor type 1 (PAI-1) in appendicitis. MATERIAL AND METHODS: Expression of uPA and expression of PAI-1 were measured in tissue specimens from patients with appendicitis (n=30) and in control specimens (n=9), using the quantitative ELISA technique. Distribution of enzymes was studied with immunohistochemistry. The uPA and PAI-1 levels in the subgroups of appendicitis and controls were compared. RESULTS: The overall expressions of uPA and PAI-1 were greater in appendicitis than in control specimens (p <0.001 and p<0.0001, respectively). Expressions of uPA and PAI-1 in phlegmonous (n=15), gangrenous (n=6) and perforated appendicitis (n=9) were all higher than those in controls (n=9), (p<0.01). Moreover, the PAI-1 level was elevated in perforated appendicitis compared with phlegmonous appendicitis (p<0.01). uPA staining was observed in connection with vascular endothelial cells and the serosa stained intensely in specimens from perforated appendicitis. CONCLUSIONS: The expression of uPA and especially the over-expression of PAI-1 seem to correlate to the progression of local inflammatory response in acute appendicitis.