Hemostatic Agents Do Not Significantly Affect Seroma Formation in Abdominal Body Contouring

BACKGROUND

Objective: Seroma formation is plaguing complication in abdominal body contouring surgery (ABCS) that has been loosely associated with the use of intraoperative hemostatic agents. The aim of this study was to investigate the association between hemostatic agent usage and seroma development following ABCS.

METHODS

A retrospective review of patients undergoing ABCS between 2010 and 2020 was completed. Cases who received hemostatic agents were matched to controls (1:2) based on potential confounders including age, BMI, and ASA score. Demographic data, operative details, and postoperative complications including development of seroma, hematoma, venous thromboembolism, wound dehiscence, and delayed wound healing were collected.

RESULTS

Seven hundred and seven patients were included in the study. Sixty-five patients (9.2%) received at least one hemostatic agent. The most used agents were topical thrombin (n = 33, 50.1%), dry matrices including oxidized cellulose, microporous polysaccharides, and absorbable gelatin matrices (n = 15, 23.1%) followed by combination fibrin sealant/thrombin preparations (n = 9, 14.0%). No significant differences with respect to demographic data or medical comorbidities between the cases and controls were identified. Bivariate analysis demonstrated no significant differences in the rate of development of seroma (OR: 0.83, 95% confidence interval [CI] = 0.23-1.99, p = 0.781), hematoma (OR: 3.72, 95% confidence interval [CI] = 0.95-14.65, p = 0.060), venous thromboembolism (OR: 0.40, 95% confidence interval [CI] = 0.44-3.81, p = 0.433).

CONCLUSION

Hemostatic agent use, regardless of type, does not significantly affect the risk of seroma, hematoma, and venous thromboembolism development, nor does it influence the rates of delayed wound healing or wound dehiscence.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Rectus Plication Does Not Increase Risk of Thromboembolic Events Following Abdominal Body Contouring: A Matched Case-Control Analysis

BACKGROUND

Rectus abdominis plication increases intra-abdominal pressure and lower-extremity venous stasis, which may increase the incidence of venous thromboembolism (VTE) events.

OBJECTIVES

The aim of this study was to investigate the potential association between VTE and rectus abdominis muscle plication during surgery.

METHODS

A retrospective review of all patients who underwent abdominal body contouring at the authors' institution between 2010 and 2020 was completed. Cases were those with postoperative VTEs and were matched to controls (1:4) via potential confounders. Variables collected include demographic data, operative details, comorbidities, and postoperative complications. Statistical analysis was performed with parametric, nonparametric, and multivariable regression modeling.

RESULTS

Overall, 1198 patients were included; 19 (1.59%) experienced a postoperative VTE and were matched to 76 controls. The overall cohort was 92.7% female with an average age of 44 years, an average Charlson Comorbidity Index of 1 point, and an average BMI of 30.1 kg/m2. History of cerebrovascular events (14.5% vs 36.8%, P = 0.026) differed significantly between cohorts, but no significant associations were noted in all other baseline demographics. Additionally, VTE cases were more likely to have received intraoperative blood transfusions (odds ratio = 8.4, P = 0.04). Bivariate analysis demonstrated cases were significantly more likely to experience concurrent complications, including delayed wound healing (0% vs 5.3%, P = 0.044), seroma formation (5.3% vs 21.1%, P = 0.027), and fat necrosis (0% vs 5.3%, P = 0.044). However, these findings were not significant in a multivariable regression model. Plication was not associated with VTE outcomes.

CONCLUSIONS

Rectus plication does not increase the risk of VTE. However, the odds of VTE are significantly increased in patients who received intraoperative blood products compared with those who did not.

LEVEL OF EVIDENCE: 3

Incidence and predictors of case cancellation within 24 h in patients scheduled for elective surgical procedures

OBJECTIVE

Avoidable case cancellations within 24 h reduce operating room (OR) efficiency, add unnecessary costs, and may have physical and emotional consequences for patients and their families. We developed and validated a prediction tool that can be used to guide same day case cancellation reduction initiatives.

DESIGN

Retrospective hospital registry study.

SETTING

University-affiliated hospitals network (NY, USA).

PATIENTS

246,612 (1/2016-6/2021) and 58,662 (7/2021-6/2022) scheduled elective procedures were included in the development and validation cohort.

MEASUREMENTS

Case cancellation within 24 h was defined as cancelling a surgical procedure within 24 h of the scheduled date and time. Our candidate predictors were defined a priori and included patient-, procedural-, and appointment-related factors. We created a prediction tool using backward stepwise logistic regression to predict case cancellation within 24 h. The model was subsequently recalibrated and validated in a cohort of patients who were recently scheduled for surgery.

MAIN RESULTS

8.6% and 8.7% scheduled procedures were cancelled within 24 h of the intended procedure in the development and validation cohort, respectively. The final weighted score contains 29 predictors. A cutoff value of 15 score points predicted a 10.3% case cancellation rate with a negative predictive value of 0.96, and a positive predictive value of 0.21. The prediction model showed good discrimination in the development and validation cohort with an area under the receiver operating characteristic curve (AUC) of 0.79 (95% confidence interval 0.79-0. 80) and an AUC of 0.73 (95% confidence interval 0.72-0.73), respectively.

CONCLUSIONS

We present a validated preoperative prediction tool for case cancellation within 24 h of surgery. We utilize the instrument in our institution to identify patients with high risk of case cancellation. We describe a process for recalibration such that other institutions can also use the score to guide same day case cancellation reduction initiatives.

Calcifying Fibrous Pseudotumor of the Neck: Diagnostic Challenges of a Rare Benign Lesion

Neck masses, frequently encountered by physicians, comprise a vast range of diagnoses, with malignancy being the greatest concern. Calcifying fibrous pseudotumor (CFP) is a rare lesion with unknown pathogenesis, characterized pathologically by a predominance of abundant hyalinized collagenous tissue with focal lymphoplasmacytic infiltrate and psammomatous or dystrophic calcifications. We present the case of a 29-year-old woman who presented with a 4-cm left neck mass, accompanied by constitutional symptoms of vague weakness and lethargy. After the lesion failed to respond to a course of antibiotic therapy, fine-needle aspiration was performed, the pathology of which was indeterminate. The concern was that the lesion was a lymphoproliferative disorder–further workup was performed. CT of the chest, abdomen, and pelvis revealed no evidence of adenopathy or neoplasms. Subsequently, an incisional biopsy was performed, suggesting a diagnosis of CFP. Magnetic resonance imaging with contrast, performed to delineate the anatomy, revealed the lesion in the left neck, deep to the left clavicle, that extended superiorly into the supraclavicular fossa. Complete surgical removal of the lesion was successfully performed, with immunophenotyping confirming the initial diagnosis of CFP. We present a case report of cervical CFP, discuss the approach to neck masses, and review the recent literature on this rare, benign entity.

In Vitro Characterization of Protein Effector Export in the Bradyzoite Stage of Toxoplasma gondii

The ubiquitous parasite Toxoplasma gondii exhibits an impressive ability to maintain chronic infection of its host for prolonged periods. Despite this, little is known regarding whether and how T. gondii bradyzoites, a quasi-dormant life stage residing within intracellular cysts, manipulate the host cell to maintain persistent infection. A previous proteomic study of the cyst wall, an amorphous layer of proteins that forms underneath the cyst membrane, identified MYR1 as a putative cyst wall protein in vitro Because MYR1 is known to be involved in the translocation of parasite-derived effector proteins into the host cell, we sought to determine whether parasites transitioning toward the bradyzoite life stage retain the capacity to translocate proteins via this pathway. By epitope tagging the endogenous loci of four known effectors that translocate from the parasitophorous vacuole into the host cell nucleus, we show, by immunofluorescence assays, that most effectors accumulate in the host nucleus at early but not late time points after infection, during the tachyzoite-to-bradyzoite transition and when parasites further along the bradyzoite differentiation continuum invade a new host cell. We demonstrate that the suppression of interferon gamma signaling, which was previously shown to be mediated by the effector TgIST, also occurs in the context of prolonged infection with bradyzoites and that TgIST export is a process that occurs beyond the early stages of host cell infection. These findings have important implications regarding how this highly successful parasite maintains persistent infection of its host.IMPORTANCEToxoplasma bradyzoites persist within tissue cysts and are refractory to current treatments, serving as a reservoir for acute complications in settings of compromised immunity. Much remains to be understood regarding how this life stage successfully establishes and maintains persistent infection. In this study, we investigated whether the export of parasite effector proteins into the host cell occurs during the development of in vitro tissue cysts. We quantified the presence of four previously described effectors in host cell nuclei at different time points after bradyzoite differentiation and found that they accumulated largely during the early stages of infection. Despite a decline in nuclear accumulation, we found that one of these effectors still mediated its function after prolonged infection with bradyzoites, and we provide evidence that this effector is exported beyond early infection stages. These findings suggest that effector export from within developing tissue cysts provides one potential mechanism by which this parasite achieves chronic infection.

Provider preferences for postoperative analgesia in obese and non-obese patients undergoing ambulatory surgery

Background

Few guidelines exist on safe prescription of postoperative analgesia to obese patients undergoing ambulatory surgery. This study examines the preferences of providers in the standard treatment of postoperative pain in the ambulatory setting.

Methods

Providers from five academic medical centers within a single US city were surveyed from May–September 2015. They were asked to provide their preferred postoperative analgesic routine based upon the predicted severity of pain for obese and non-obese patients. McNemar’s tests for paired observations were performed to compare prescribing preferences for obese vs. non-obese patients. Fisher’s exact tests were performed to compare preferences based on experience: > 15 years vs. ≤15 years in practice, and attending vs. resident physicians.

Results

A total of 452 providers responded out of a possible 695. For mild pain, 119 (26.4%) respondents prefer an opioid for obese patients vs. 140 (31.1%) for non-obese (p = 0.002); for moderate pain, 329 (72.7%) for obese patients vs. 348 (77.0%) for non-obese (p = 0.011); for severe pain, 398 (88.1%) for obese patients vs. 423 (93.6%) for non-obese (p < 0.001). Less experienced physicians are more likely to prefer an opioid for obese patients with moderate pain: 70 (62.0%) attending physicians with > 15 years in practice vs. 86 (74.5%) with ≤15 years (p = 0.047), and 177 (68.0%) attending physicians vs. 129 (83.0%) residents (p = 0.002).

Conclusions

While there is a trend to prescribe less opioid analgesics to obese patients undergoing ambulatory surgery, these medications may still be over-prescribed. Less experienced physicians reported prescribing opioids to obese patients more frequently than more experienced physicians.

A perioperative care map improves outcomes in patients with morbid obesity undergoing major surgery

BACKGROUND

The surgical management of patients with morbid obesity (body mass index ≥ 40) is notable for a relatively high risk of complications. To address this problem, a perioperative care map was developed using precautions and best practices commonly employed in bariatric surgery. It requires additional medical assessments, sleep apnea surveillance, more stringent guidelines for anesthetic management, and readily available bariatric operating room equipment, among other items. This care map was implemented in 2013 at 4 major urban teaching hospitals for use in patients undergoing all types of nonambulatory surgery with a body mass index greater than 40 kg/m². The impact on patient outcomes was evaluated.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was used to compare 30-day outcomes of morbidly obese patients before the year 2013 and after the years 2015 care-map implementation. In addition, trends in 30-day outcomes for morbidly obese patients were compared with those for non-obese patients.

RESULTS

Morbidly obese patients, between 2013 and 2015, saw an adjusted decrease in the rate of unplanned return to the operating room (OR = 0.49; P = .039), unplanned readmission (OR = 0.57; P = .006), total duration of stay (-0.87 days; P = .009), and postoperative duration of stay (-0.69 days; P = .007). Of these, total duration of stay (-0.86 days; P = .015), and postoperative duration of stay (-0.69 days; P = .012) improved significantly more for morbidly obese patients than for nonmorbidly obese patients.

CONCLUSION

Outcomes in morbidly obese patients improved from 2013 to 2015. Implementation of a perioperative care map may have contributed to these improvements. The care map should be further investigated and considered for more widespread use.

Perioperative care map improves compliance with best practices for the morbidly obese

BACKGROUND

Morbid obesity can complicate perioperative management. Best practice guidelines have been published but are typically followed only in bariatric patients. Little is known regarding physician awareness of and compliance with these clinical recommendations for nonbariatric operations. Our study evaluated if an educational intervention could improve physician recognition of and compliance with established best practices for all morbidly obese operatively treated patients.

METHODS

A care map outlining best practices for morbidly obese patients was distributed to all surgeons and anesthesiologists at 4 teaching hospitals in 2013. Pre- and postintervention surveys were sent to participants in 2012 and in 2015 to evaluate changes in clinical practice. A chart audit performed postintervention determined physician compliance with distributed guidelines.

RESULTS

In the study, 567 physicians completed the survey in 2012 and 375 physicians completed the survey in 2015. Postintervention, statistically significant improvements were seen in the percentage of surgeons and anesthesiologists combined who reported changing their management of morbidly obese, operatively treated patients to comply with best practices preoperatively (89% vs 59%), intraoperatively (71% vs 54%), postoperatively (80% vs 57%), and overall (88% vs 72%). Results were similar when surgeons and anesthesiologists were analyzed separately. A chart audit of 170 cases from the 4 hospitals found that 167 (98%) cases were compliant with best practices.

CONCLUSION

After care map distribution, the percentage of physicians who reported changing their management to match best practices significantly improved. These findings highlight the beneficial impact this educational intervention can have on physician behavior. Continued investigation is needed to evaluate the influence of this intervention on clinical outcomes.

Levels of elevated circulating endothelial cell decline after tumor resection in patients with pancreatic ductal adenocarcinoma

AIM

To evaluate circulating endothelial lineage cells (ELCs) as biomarkers of tumor neovascularization in patients with pancreatic ductal adenocarcinoma (PDAC).

MATERIALS AND METHODS

ELCs were isolated from the peripheral blood of patients with PDAC (n=14) or controls (n=17) before and after tumor resection/surgery and quantified using flow cytometry. Vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) were detected in tumor using immunohistochemistry and in plasma using an ELISA technique.

RESULTS

Circulating ELC levels were increased in patients with PDAC compared to controls. After PDAC resection, ELC levels declined. ELC level increases were associated with cancer recurrence. VEGF and PlGF were identified in cancer cells and exocrine pancreas cells. Only PlGF was detected in tumor-associated inflammatory cells. Plasma levels of PlGF were higher in patients with PDAC compared to controls.

CONCLUSION

Circulating ELCs are a potential biomarker of PDAC neovascularization, and PlGF may be an important target in treatment of PDAC.

Identification of Helicobacter spp. in bile and gallbladder tissue of patients with symptomatic gallbladder disease

BACKGROUND

This experimental study was designed to determine if Helicobacter spp. contribute to benign gallbladder disease using polymerase chain reaction (PCR) methods.

METHODS

Patients with benign gallbladder disease scheduled for elective cholecystectomy at New York University Langone Medical Center were recruited from February to May 2008. Bile, gallbladder tissue and gallstones were collected. DNA was isolated from these specimens and amplified via PCR using C97F and C98R primers specific for Helicobacter spp. Appropriate positive and negative controls were used. Products were analysed with agarose gel electrophoresis, sequenced and results aligned using sequencher. Plasma was collected for detection of anti-Helicobacter pylori antibodies via enzyme-linked immunosorbent assay.

RESULTS

Of 36 patients, 12 patients' bile and/or tissue were positive for Helicobacter spp. by PCR. Species were most homologous with H. pylori, although other Helicobacter spp. were suggested. Six of 12 patients demonstrated anti-Helicobacter antibodies in plasma, suggesting that the remaining six might have demonstrated other species besides H. pylori. Four of six plasma samples with anti-Helicobacter antibodies were anti-CagA (cytotoxin associated gene) negative.

DISCUSSION

Helicobacter spp. can be detected in bile and gallbladder tissue of patients with benign gallbladder disease. The contribution of these bacteria to the pathophysiology of gallbladder disease and gallstone formation requires further study.

Management and spectrum of complications in patients undergoing surgical debridement for pancreatic necrosis

Patients who undergo pancreatic necrosectomy frequently develop complications and often have high mortality rates. These patients are best cared for at specialized centers to minimize morbidity, manage complex complications, and reduce mortality. We present a review of our experience and describe the spectrum of complications encountered in managing of these difficult patients. A registry of patients undergoing pancreatic necrosectomy during a 7-year period was analyzed for preoperative clinical scoring systems (Acute Physiology and Chronic Health Evaluation [APACHE] II and APACHE III scores), patient characteristics related to necrosectomy, and morbidity and mortality. Twenty-nine patients underwent necrosectomy. Indications for surgery were consistent with those previously described. There were 27 complications in 22 patients. Sixteen complications were early (less than 3 weeks after surgery) and 14 were late. The mortality rate was 14 per cent. All deaths were in patients transferred from outside institutions, some after extended time periods. Temporary percutaneous catheter drainage of abscesses before transfer and definitive surgery appeared to reduce mortality in transferred patients. There was a statistically significant correlation between mean maximal preoperative APACHE III score, but not APACHE II score, and the number of postoperative intensive care unit days (rho = 0.52, P = 0.004). We describe our experience managing patients with infected pancreatic necrosis that required operative necrosectomy. We found that more severely ill patients (higher APACHE III scores) had longer intensive care unit stays, but the initial severity of their illness did not increase mortality. If patients with infected pancreatic necrosis are referred to specialized centers, preoperative pretransfer percutaneous drainage may serve to temporarily control sepsis.

Management and Spectrum of Complications in Patients Undergoing Surgical Debridement for Pancreatic Necrosis

Patients who undergo pancreatic necrosectomy frequently develop complications and often have high mortality rates. These patients are best cared for at specialized centers to minimize morbidity, manage complex complications, and reduce mortality. We present a review of our experience and describe the spectrum of complications encountered in managing of these difficult patients. A registry of patients undergoing pancreatic necrosectomy during a 7-year period was analyzed for preoperative clinical scoring systems (Acute Physiology and Chronic Health Evaluation [APACHE] II and APACHE III scores), patient characteristics related to necrosectomy, and morbidity and mortality. Twenty-nine patients underwent necrosectomy. Indications for surgery were consistent with those previously described. There were 27 complications in 22 patients. Sixteen complications were early (less than 3 weeks after surgery) and 14 were late. The mortality rate was 14 per cent. All deaths were in patients transferred from outside institutions, some after extended time periods. Temporary percutaneous catheter drainage of abscesses before transfer and definitive surgery appeared to reduce mortality in transferred patients. There was a statistically significant correlation between mean maximal preoperative APACHE III score, but not APACHE II score, and the number of postoperative intensive care unit days (rho = 0.52, P = 0.004). We describe our experience managing patients with infected pancreatic necrosis that required operative necrosectomy. We found that more severely ill patients (higher APACHE III scores) had longer intensive care unit stays, but the initial severity of their illness did not increase mortality. If patients with infected pancreatic necrosis are referred to specialized centers, preoperative pre-transfer percutaneous drainage may serve to temporarily control sepsis.

Nonfunctioning Pancreatic Endocrine Neoplasm Presenting as Asymptomatic, Isolated Pancreatic Duct Stricture: A Case Report and Review of the Literature

Morphologic irregularities of the pancreatic duct are often noted on abdominal imaging studies obtained for unrelated symptoms or conditions. We report the case of a patient who was found to have an incidental, isolated pancreatic duct dilatation on multiple imaging studies and who was found to have a nonfunctioning pancreatic endocrine neoplasm at resection. His prognosis is excellent based on the histology of the lesion and a curative resection. This case highlights the importance of fully investigating incidental pancreatic duct abnormalities regardless of the setting in which they are found.

Nonfunctioning pancreatic endocrine neoplasm presenting as asymptomatic, isolated pancreatic duct stricture: a case report and review of the literature

Morphologic irregularities of the pancreatic duct are often noted on abdominal imaging studies obtained for unrelated symptoms or conditions. We report the case of a patient who was found to have an incidental, isolated pancreatic duct dilatation on multiple imaging studies and who was found to have a nonfunctioning pancreatic endocrine neoplasm at resection. His prognosis is excellent based on the histology of the lesion and a curative resection. This case highlights the importance of fully investigating incidental pancreatic duct abnormalities regardless of the setting in which they are found.

Retroperitoneal perforation of the duodenum from biliary stent erosion

Endoscopically placed biliary stents have supplanted surgical decompression as the preferred treatment option for patients with obstructive jaundice from advanced pancreatic cancer. An unusual complication of indewelling biliary stents is duodenal perforation into the retroperitoneum. We describe the case of a patient with end-stage pancreatic cancer who presented with an acute abdomen from erosion of a previously placed bile duct stent through the wall of the second portion of the duodenum. Although our patient presented with advanced symptoms, clinical presentations can vary from mild abdominal discomfort and general malaise to overt septic shock. Definitive diagnosis is best made with computed tomography (CT) imaging, which can detect traces of retroperitoneal air and fluid. Treatment options vary from nonoperative management with antibiotics, bowel rest, and parenteral alimentation in the most stable patients to definitive surgery with complete diversion of gastric contents and biliary flow from the affected area in patients with clinical symptoms or radiologic evidence suggesting extensive contamination. Complications of management can include duodenal fistulization, residual retroperitoneal or intrabdominal abscess, and ongoing sepsis. This report highlights the salient issues in the presentation, diagnosis, and modern management of patients with this rare complication of indwelling biliary stents.

Evaluation of pro-carboxypeptidase A and carboxypeptidase A as serologic markers for adenocarcinoma of the pancreas

BACKGROUND

A serological marker for pancreatic cancer may allow for early detection and potentially more effective treatments. Pro-carboxypeptidase A (pro-CPA) is produced exclusively in the pancreas and converted to its active form, CPA, in the intestinal lumen. We hypothesized that alterations in serum pro-CPA and/or CPA may be useful as a diagnostic test for pancreatic cancer.

PATIENTS AND METHODS

Serum samples obtained from 34 patients with pancreatic adenocarcinoma prior to surgical intervention and 64 control patients were assayed for pro-CPA and CPA. A variety of statistical methods was used to evaluate the utility of these measurements individually and in combination to classify the samples with respect to the presence or absence of pancreatic adenocarcinoma.

RESULTS

Because of positive skewing of the data in some populations, transformation of the data to natural logarithmic scales was used and resulted in normal distributions. All pancreatic cancer patients had ln(CPA) levels within or below the normal range defined as two standard deviations from the control group mean (-2.714+/-0.413). Ln(pro-CPA) levels in 24 of 34 cancer patients were outside the normal range of the control group (0.306+/-0.33). Pancreatic cancer patients with ln pro-CPA values within the control range had low ln CPA, advanced stage and/or evidence of pancreatic insufficiency. While each of these individual values (ln pro-CPA or ln CPA) does not adequately separate all control from cancer patients, a bivariate classification rule is presented that uses both ln pro-CPA and ln CPA simultaneously to predict the presence of pancreatic cancer with a sensitivity of 91% and a specificity of 95%.

CONCLUSIONS

The data presented suggest that abnormalities in serum pro-CPA and CPA levels are associated with the presence of pancreatic cancer.

Calcifying fibrous pseudotumor of the neck: diagnostic challenges of a rare benign lesion

Neck masses, frequently encountered by physicians, comprise a vast range of diagnoses, with malignancy being the greatest concern. Calcifying fibrous pseudotumor (CFP) is a rare lesion with unknown pathogenesis, characterized pathologically by a predominance of abundant hyalinized collagenous tissue with focal lymphoplasmacytic infiltrate and psammomatous or dystrophic calcifications. We present the case of a 29-year-old woman who presented with a 4-cm left neck mass, accompanied by constitutional symptoms of vague weakness and lethargy. After the lesion failed to respond to a course of antibiotic therapy, fine-needle aspiration was performed, the pathology of which was indeterminate. The concern was that the lesion was a lymphoproliferative disorder-further workup was performed. CT of the chest, abdomen, and pelvis revealed no evidence of adenopathy or neoplasms. Subsequently, an incisional biopsy was performed, suggesting a diagnosis of CFP. Magnetic resonance imaging with contrast, performed to delineate the anatomy, revealed the lesion in the left neck, deep to the left clavicle, that extended superiorly into the supraclavicular fossa. Complete surgical removal of the lesion was successfully performed, with immunophenotyping confirming the initial diagnosis of CFP. We present a case report of cervical CFP, discuss the approach to neck masses, and review the recent literature on this rare, benign entity.

Successful Treatment of Bouveret Syndrome Using Holmium: YAG Laser Lithotripsy

Although gallstone disease is highly prevalent, cholelithiasis causing gallstone ileus is uncommon. Consideration has been given for nonoperative strategies to resolve obstruction due to the significant age and comorbidities afflicting this population. A 94-year-old man presented with a 5-day history of abdominal distension and tenderness. CT scan revealed multiple large gallstones within the gallbladder, pneumobilia, and two ectopic gallstones (antrum of the stomach and distal ileum). The patient was taken to the operating room where an enterolithotomy and gastrotomy was performed with removal of gallstones and subsequent relief of obstruction. During the postoperative course, the patient developed symptoms of gastric outlet obstruction and underwent gastrointestinal endoscopy for diagnosis and treatment. Two large gallstones, present in the duodenum, were retracted into the stomach using a Roth net but could not be retrieved beyond the upper esophageal sphincter. A holmium: yttrium-aluminum-garnet (Holmium: YAG) laser was used for fragmentation of the stones, with subsequent successful removal. This is the first documented successful use of the holmium: YAG laser for the treatment of recurrent gallstone ileus. Physicians should remember that in a small but important subgroup of patients, endoscopy accompanied by laser lithotripsy may prove beneficial.

Successful treatment of Bouveret syndrome using holmium: YAG laser lithotripsy

Although gallstone disease is highly prevalent, cholelithiasis causing gallstone ileus is uncommon. Consideration has been given for nonoperative strategies to resolve obstruction due to the significant age and comorbidities afflicting this population. A 94-year-old man presented with a 5-day history of abdominal distension and tenderness. CT scan revealed multiple large gallstones within the gallbladder, pneumobilia, and two ectopic gallstones (antrum of the stomach and distal ileum). The patient was taken to the operating room where an enterolithotomy and gastrotomy was performed with removal of gallstones and subsequent relief of obstruction. During the postoperative course, the patient developed symptoms of gastric outlet obstruction and underwent gastrointestinal endoscopy for diagnosis and treatment. Two large gallstones, present in the duodenum, were retracted into the stomach using a Roth net but could not be retrieved beyond the upper esophageal sphincter. A holmium: yttrium-aluminum-garnet (Holmium: YAG) laser was used for fragmentation of the stones, with subsequent successful removal. This is the first documented successful use of the holmium: YAG laser for the treatment of recurrent gallstone ileus. Physicians should remember that in a small but important subgroup of patients, endoscopy accompanied by laser lithotripsy may prove beneficial.

Perforated duodenal diverticulitis: a report of three cases

BACKGROUND

Duodenal diverticuli are present in up to 22% of the population. However, perforation of a duodenal diverticulum with spillage of enteric contents into the retroperitoneum is rare.

METHODS

We report three cases of perforated duodenal diverticulitis.

RESULTS

Clinical presentations varied widely from patients with acute abdominal findings and generalized sepsis to a patient with mild symptoms of abdominal discomfort. CT scanning was the imaging modality used to make an accurate diagnosis. Treatment approaches for the most stable patient included nonoperative management with antibiotics, bowel rest and parenteral alimentation, while the less stable patients underwent definitive surgery with complete diversion of gastric contents and biliary flow from the affected area of duodenum.

CONCLUSIONS

This report highlights the salient issues in the presentation, diagnosis and modern management of patients with this potentially catastrophic disease.

Hematopoietic stem cells and endothelial cell precursors express Tie-2, CD31 and CD45

Early theories of tumor angiogenesis suggested that preexisting vessels surrounding the tumor were the principal source of the tumor vasculature but recent evidence suggests that endothelial progenitor cells (EPC) migrate from the marrow play an important role in developing the tumor blood supply. In a mouse model, in which the vascularization of a transplantable tumor was studied after bone marrow (BM) transplantation, we show that cells that express Tie-2, Sca-1, CD31 and CD45 function as both BM EPC and primitive hematopoietic stem cells. BM cells from transgenic mice expressing green fluorescent protein (GFP) under the control of the endothelial lineage-specific Tie-2 promoter (Tie-2 /GFP) were used to reconstitute irradiated (12 Gy) wild-type mice. Five donor BM cell populations were studied: (1) whole BM; (2) Sca-1-enriched BMC; (3) GFP/Tie-2+, Sca-1+ BMC; (4) GFP/Tie-2-, Sca-1+ BMC and (5) Sca-1-depleted BMC. After 4 weeks, the mice were injected with Tg.AC tumor cells. Three weeks later, sections from the tumors were stained for CD31 and examined for Tie-2-driven GFP expression. BM-derived endothelial cells were found only in mice transplanted with bone marrow containing populations of Tie-2+, Sca-1+ cells. As few as 3500 of these cells were sufficient to radioprotect lethally irradiated mice. Thus, we conclude that a rare subset of BMC (approximately 4 x 10(-3)%) with the putative properties of hemangioblasts have an active Tie-2 promoter. Selection of Tie-2+Sca-1+ BMC enriches for marrow-derived EPCs that participate in tumor angiogenesis and cells that can provide hematopoietic reconstitution of marrow-ablated mice.

Adenosine A(2A) receptor activation promotes wound neovascularization by stimulating angiogenesis and vasculogenesis

Recent reports indicate that circulating endothelial progenitor cells (EPCs) may be recruited to sites of neovascularization where they differentiate into endothelial cells (EC). As we have previously demonstrated that adenosine A(2A) agonists promote neovascularization in wounds, we sought to determine whether adenosine A(2A) receptor agonist-augmented wound healing involves vessel sprouting (angiogenesis) or EPC recruitment (vasculogenesis) or both. Four weeks after bone marrow reconstitution from donor FVB/N Tie2GFP transgenic mice, two full-thickness excisional wounds were performed on the dorsum of FVB/N wild-type mice and treated with either an A(2A) receptor agonist (CGS-21680) or vehicle alone. Vessel density, as measured by CD31 staining, and density of EPC-derived vessels, as measured by GFP expression, were quantified in a blinded fashion using two-color fluorescence microscopy. We observed nearly a threefold increase in CD31-positive vessels and a more than 10-fold increase in GFP-positive cells in A(2A) agonist-treated 3-day old wounds, but by 6 days after wounding the differences between A(2A) agonist-treated and vehicle-treated wounds were no longer statistically significant. In conclusion, this is the first evidence that an exogenous agent such as an adenosine A(2A) receptor agonist increases neovascularization in the early stages of wound repair by increasing both EPC recruitment (vasculogenesis) and local vessel sprouting (angiogenesis).

Experimental hindlimb ischemia leads to neutrophil-mediated increases in gastrocnemius MMP-2 and -9 activity: a potential mechanism for ischemia induced MMP activation

INTRODUCTION

Matrix metalloproteinases (MMP)-2 and -9 are Type 4 collagenases instrumental in basement membrane degradation, a process necessary for angiogenesis to occur. Polymorphonuclear leukocytes (PMNs) contain MMP-9, and in the presence of both PMN-derived serine protease and membrane type 1 (MT1)-MMP, are able to activate pro-MMP-2 following hindlimb ischemia. We hypothesized that neutrophil depletion (ND) of animals prior to hindlimb ischemia (HI) would abrogate the activation of pro-MMP-2 and decrease the level of MMP-9

MATERIALS AND METHODS

12 FVB/N Tie2/LacZ-182 SATO female mice were randomly divided into four blinded groups; HI + PBS, HI + anti-PMN antibody (GR-1), HI + isotype matched control antibody (IgG(2b,K)), and no HI + PBS. PMN depletion was achieved prior to the time of ischemia and maintained until sacrifice. HI was achieved by unilateral femoral artery ligation. Three days postligation the animals were sacrificed and the gastrocnemius muscle from each hindlimb was harvested. MMP-2 and -9 (gelatin zymography) and MT1-MMP (Western blot) expression and activation were quantified by densitometry and NIH Image Analysis software. MMP values were expressed as a ratio of ischemic-to-nonischemic hindlimbs and compared between groups. Statistical significance was determined with analysis of variance (ANOVA) RESULTS: Zymograms revealed a greater than 10-fold increase in active MMP-9 and greater than 4-fold increase in active MMP-2 from HI + PBS compared to no HI + PBS (P < 0.05). HI + anti-PMN antibody demonstrated reduction of both active MMP-2 and -9 levels to that of the nonischemic group. Pro-MMP-2 was constitutively expressed in all four groups with no significant differences between any group (P = NS). There was no difference between the HI + isotype-matched antibody group and the HI + PBS group throughout the experiments (P = NS). ND did not affect MT1-MMP activation or expression

CONCLUSIONS

Limb ischemia causes activation of MMP-2 and -9, which is eliminated by ND. ND animals undergoing hindlimb ischemia exhibit identical levels of active MMP-2 and -9 as animals that did not have hindlimb ischemia. Neutrophils may be an important activator of MMP-2 and the suppliers of MMP-9 in the ischemic hindlimb and may be essential for tissue remodeling, basement membrane degradation, and angiogenesis in ischemic limbs

Management of complex biliary tract calculi with a holmium laser

The difficulty in managing complex biliary tract calculi is exemplified in patients with primary intrahepatic calculi. Standard surgical and endoscopic approaches often fail to clear calculi in these patients who have recurrent episodes of cholangitis. The success of the holmium laser for urologic calculi led us to adapt treatment strategies for primary and secondary biliary tract calculi where standard treatments had been unsuccessful. Our goals were to remove all calculi, prevent recurrent sepsis, and preserve hepatic parenchyma. Thirty-six patients with complex biliary calculi were treated. After sepsis was controlled and the extent of calculi was evaluated, appropriate access to and drainage of the biliary tract was achieved. Holmium laser lithotripsy was performed under video guidance using flexible choledochoscopes and a 200 micro laser fiber generating 0.6 to 1.0 joules at frequencies of 6 to 10 Hz. Lithotripsy procedures were repeated until cholangiography and cholangioscopy confirmed the clearance of calculi. Twenty-two patients of Asian descent with primary intrahepatic calculi and 14 patients with secondary intrahepatic calculi were treated. Access to the biliary tract could be accomplished through percutaneous catheter tracts, T-tube tracts, or the cystic duct during laparoscopic cholecystectomy. Biliary drainage was by biliary enteric anastomosis or endoscopic sphincterotomy. Complete stone clearance required an average of 3.9 procedures (range 1 to 15) for patients with primary intrahepatic calculi and 2.6 procedures (range 1 to 10) for patients with secondary intrahepatic calculi regardless of stone composition. No patient required hepatic resection and no complications or deaths were attributed to the holmium laser. Clearance of calculi can reliably and safely be achieved with a holmium laser regardless of stone composition or location while preserving hepatic parenchyma and preventing recurrent sepsis.

Systemic tumor targeting and killing by Sindbis viral vectors

Successful cancer gene therapy requires a vector that systemically and specifically targets tumor cells throughout the body. Although several vectors have been developed to express cytotoxic genes via tumor-specific promoters or to selectively replicate in tumor cells, most are taken up and expressed by just a few targeted tumor cells. By contrast, we show here that blood-borne Sindbis viral vectors systemically and specifically infect tumor cells. A single intraperitoneal treatment allows the vectors to target most tumor cells, as demonstrated by immunohistochemistry, without infecting normal cells. Further, Sindbis infection is sufficient to induce complete tumor regression. We demonstrate systemic vector targeting of tumors growing subcutaneously, intrapancreatically, intraperitoneally and in the lungs. The vectors can also target syngeneic and spontaneous tumors in immune-competent mice. We document the anti-tumor specificity of a vector that systemically targets and eradicates tumor cells throughout the body without adverse effects.

Inhibition of matrix metalloproteinases reduces local and distant organ injury following experimental acute pancreatitis

BACKGROUND

Pulmonary complications from pancreatitis involve parenchymal destruction via proteolytic enzymes. Matrix metalloproteinases (MMPs) may play an important role in pulmonary injury following acute severe pancreatitis. We hypothesized that local and distant organ injury would be decreased by the presence of an MMP inhibitor (Batimistat; BB-94) following severe acute pancreatitis (AP).

METHODS

Eighteen male rats were randomized into two groups: BB-94 (AP + 40 mg/kg/24 h BB-94 ip x three doses) or control (AP + 20 ml/kg/24 h normal saline ip x three doses). Necrotizing AP was induced by retrograde infusion of 5% sodium taurocholate (1.5 ml/kg) into the pancreatic duct. Twenty additional animals were randomized into BB-94 and control groups for the survival study. Serum was evaluated for amylase and MMP activity. Pancreatic sections were graded for edema, necrosis, neutrophil infiltrate, and hemorrhage. Myloperoxidase (MPO) activity was used to determine PMN infiltration in the lung. Evan's Blue dye extravasation was used to quantify vascular permeability.

RESULTS

Animals in the BB-94 group had decreased amylase levels (1086.0 +/- 61.7 U/L vs 2232.7 +/- 309.9 U/L; P < 0.05), decreased cellular infiltrate (1.4 +/- 0.2 vs 2.3 +/- 0.2; P < 0.02), and decreased necrosis (4.1 +/- 0.3 vs 6.1 +/- 0.4; P < 0.005) compared to the control group. Lung tissue following pancreatitis in the BB-94 group demonstrated decreased MPO activity (41.5 +/- 2.4 units vs 57.3 +/- 2.9 units; P < 0.05) and decreased vascular permeability (18.3 +/- 2.8 mg/100 g vs 30.1 +/- 4.6 mg/100 g; P < 0.05). Animals treated with BB-94 had 100% survival compared to 50% survival in control at 72 h.

CONCLUSIONS

Pancreatitis results in increased local and distant MMP activity. Pulmonary and pancreatic injury following AP can be abrogated by treatment with an MMP inhibitor (Batimistat; BB-94) which may result in decreased morbidity and mortality.

Experimental hindlimb ischemia increases neutrophil-mediated matrix metalloproteinase activity: a potential mechanism for lung injury after limb ischemia

BACKGROUND

Acute limb ischemia initiates a systemic inflammatory response, including pulmonary polymorphonuclear leukocyte (PMN) sequestration and acute lung injury. Lung injury is partly attributed to release by PMN's of extracellular matrix (ECM) modifying metalloproteinases (MMPs). We hypothesized that acute hindlimb ischemia (HI) would increase MMP activity in the lung and other organs and that systemic neutrophil depletion before HI would block this effect.

STUDY DESIGN

Seventeen FVB/N Tie2/LacZ-182 SATO female mice were randomly divided into four groups: HI + PBS (Group 1), HI + antineutrophil antibody (Group 2), HI + isotype matched control antibody (Group 3), and no HI + PBS (Group 4). HI was achieved by unilateral femoral artery ligation. Neutrophil depletion was confirmed. Three days postligation, lung, liver, and kidney were harvested. MMP-2 and -9 expression and activation (gelatin zymography) and membrane type-1 MMP (MT1-MMP, western blotting) were quantified by densitometry and NIH Image Analysis software. Statistical significance was determined with an analysis of variance.

RESULTS

Zymograms revealed a 46% increase in pulmonary proMMP-9 in Group 1 versus Group 4 (6,107 +/- 472 [mean +/- SEM] densitometry units [DU] versus 3,287 +/- 675 DU, p < 0.05). A similar trend was observed for active MMP-9 (3,189 +/- 541 DU versus 1,417 +/- 927 DU, P = 0.16). Neutrophil depletion (Group 2) decreased proMMP-9 levels by 51% (2,996 +/- 314 DU versus 6,107 +/- 472 DU, p < 0.05) and active MMP-9 by 75% (810 +/- 444 DU versus 3,189 +/- 541 DU, p < 0.05) compared with Group 1. Active MMP-2 increased 51% after HI (Group 1, 3,230 +/- 86 DU versus Group 4, 1,599 +/- 327 DU, p < 0.05). Neutrophil depletion decreased the HI-induced activation of MMP-2 by 43% (Group 2, 1,829 +/- 471 DU versus Group 1, 3,230 +/- 86 DU, p < 0.05).

CONCLUSIONS

HI increases pulmonary proMMP-9, active MMP-9, and active MMP-2 levels. Neutrophil depletion blocks this effect. These data suggest that acute limb ischemia leads to PMN-mediated changes in MMP activity.

Temporal expression and activation of matrix metalloproteinases-2, -9, and membrane type 1-matrix metalloproteinase following acute hindlimb ischemia

OBJECTIVE

Matrix metalloproteinase (MMP) activity is essential for remodeling of ischemic tissue. The murine hindlimb ischemia model exhibits tissue remodeling including revascularization in part due to angiogenesis. MMP-2 and -9 are type IV collagenases necessary for basement membrane degradation as a part of extracellular matrix remodeling and angiogenesis. Polymorphonuclear leukocytes (PMNs) contain MMP-9, and in the presence of membrane type 1 (MT1)-MMP, are able to activate proMMP-2 in vitro. Activation of MMP-2 and -9 may be essential in ischemic limbs both for tissue remodeling and revascularization via angiogenesis. We hypothesized that MMP-2 and -9 would be activated following acute hindlimb ischemia (HI), and this activation would be temporally related to PMN infiltration.

DESIGN OF STUDY

HI was achieved by unilateral femoral artery ligation in 20 FVB/N mice. Five mice underwent sham operation without hindlimb ischemia. Gastrocnemius muscle was harvested from both hindlimbs at 1, 3, 14, and 30 days following ligation and assayed for MMP-2, -9 (gelatin zymography), and MT1-MMP (Western blotting). MMP-2 and -9 expression and activation were analyzed by gelatin zymography and quantified by densitometry with NIH Image Analysis software. Neutrophils per high power field were counted. The results were expressed as a ratio of ischemic to nonischemic limbs and compared at each time point using ANOVA.

RESULTS

Zymographic analysis revealed a 212% increase in active MMP-2 3 days postligation (P <.05). Active MMP-9 reached its maximum level (800% over baseline) on postoperative day 3 and continued to be elevated on day 14 (737% over baseline) (P <.05). The increase in active MMP-2 and -9 levels paralleled PMN infiltration that also peaked 3 days postligation (1184% over baseline) (P <.05). PMN count, MMP-2, and -9 all returned to baseline levels by postoperative Day 30. MT1-MMP was present in tissue samples from all time points as confirmed by Western blot.

CONCLUSIONS

Limb ischemia causes an early activation of MMP-2 and -9 in temporal relation to PMN infiltration. HI may prime PMNs, leading to their sequestration in ischemic tissue. Primed PMNs, along with constitutively expressed MT1-MMP, may activate MMPs-2 and -9 and enable tissue remodeling essential for limb revascularization and angiogenesis.

Inhibition of matrix metalloproteinases reduces local and distant organ injury following experimental acute pancreatitis

BACKGROUND

Pulmonary complications from pancreatitis involve parenchymal destruction via proteolytic enzymes. Matrix metalloproteinases (MMPs) may play an important role in pulmonary injury following acute severe pancreatitis. We hypothesized that local and distant organ injury would be decreased by the presence of an MMP inhibitor (Batimistat; BB-94) following severe acute pancreatitis (AP).

METHODS

Eighteen male rats were randomized into two groups: BB-94 (AP + 40 mg/kg/24 h BB-94 ip x three doses) or control (AP + 20 ml/kg/24 h normal saline ip x three doses). Necrotizing AP was induced by retrograde infusion of 5% sodium taurocholate (1.5 ml/kg) into the pancreatic duct. Twenty additional animals were randomized into BB-94 and control groups for the survival study. Serum was evaluated for amylase and MMP activity. Pancreatic sections were graded for edema, necrosis, neutrophil infiltrate, and hemorrhage. Myloperoxidase (MPO) activity was used to determine PMN infiltration in the lung. Evan's Blue dye extravasation was used to quantify vascular permeability.

RESULTS

Animals in the BB-94 group had decreased amylase levels (1086.0 +/- 61.7 U/L vs 2232.7 +/- 309.9 U/L; P < 0.05), decreased cellular infiltrate (1.4 +/- 0.2 vs 2.3 +/- 0.2; P < 0.02), and decreased necrosis (4.1 +/- 0.3 vs 6.1 +/- 0.4; P < 0.005) compared to the control group. Lung tissue following pancreatitis in the BB-94 group demonstrated decreased MPO activity (41.5 +/- 2.4 units vs 57.3 +/- 2.9 units; P < 0.05) and decreased vascular permeability (18.3 +/- 2.8 mg/100 g vs 30.1 +/- 4.6 mg/100 g; P < 0.05). Animals treated with BB-94 had 100% survival compared to 50% survival in control at 72 h.

CONCLUSIONS

Pancreatitis results in increased local and distant MMP activity. Pulmonary and pancreatic injury following AP can be abrogated by treatment with an MMP inhibitor (Batimistat; BB-94) which may result in decreased morbidity and mortality.

Polymorphonuclear neutrophils promote rFGF-2-induced angiogenesis in vivo

BACKGROUND

The role of neutrophils in angiogenesis remains largely unknown. Recent evidence has shown that polymorphonuclear neutrophils (PMNs) produce several proangiogenic cytokines, including VEGF, TNF-alpha, IL-1, IL-6, and IL-8. In addition, PMN-derived proteinases promote endothelial cell migration. We hypothesized that PMNs may facilitate angiogenesis and that reducing circulating PMNs might alter the host angiogenic response.

MATERIALS AND METHODS

We utilized a corneal pocket assay to compare rFGF-2-induced vessel formation in the corneas of mice with normal levels of circulating neutrophils to those in a neutropenic state. Circulating PMNs were reduced using serial intraperitoneal injections of monoclonal antibody to Gr-1. Slow release rFGF2 pellets were implanted into the corneas of neutropenic mice and controls. Corneal neovascularization, measured as vessel length and area of vessel in-growth, was quantified using slit-lamp microscopy on day 7.

RESULTS

The average number of circulating PMNs was significantly reduced in the experimental group compared to the control group on days 1-7 (P < 0.05). No statistical differences in circulating monocytes or lymphocytes were observed from days 0 to 6. Mice in the experimental group had a vascular area of 2.58 +/- 0.2 mm(2) compared to 3.55 +/- 0.3 mm(2) in the control group (P < 0.05).

CONCLUSIONS

Corneal neovascularization in response to rFGF-2 is diminished by PMN depletion. PMNs play an important role in facilitating rFGF-2-induced angiogenesis.

Increased membrane type 1 matrix metalloproteinase expression from adenoma to colon cancer: a possible mechanism of neoplastic progression

PURPOSE

Membrane type 1 matrix metalloproteinase is a membrane-associated matrix metalloproteinase central to the degradation of basement membrane components via the activation of matrix metalloproteinase-2. Although membrane type 1 matrix metalloproteinase is overexpressed in invasive colon cancer, its expression in colonic polyps and carcinoma in situ has not been defined. In addition, the association of membrane type 1 matrix metalloproteinase expression by a primary tumor and recurrence of colon cancers has not been examined.

METHODS

Immunoperoxidase staining was performed on randomly selected specimens containing adenoma (n = 17), carcinoma in situ (n = 9), or metastatic colon carcinoma (n = 8) with mouse monoclonal antibody to human membrane type 1 matrix metalloproteinase. Similar staining was also performed on randomly selected node-negative colon cancers that recurred within five years of resection (n = 17), matched for age, gender, stage, grade, and vascular, lymphatic, and perineural invasion, and node-negative colon cancers that did not recur within five years of resection (n = 17). Staining for membrane type 1 matrix metalloproteinase was graded. Mean scores for the groups were compared by Wilcoxon test.

RESULTS

We found a progressive and significant increase in the mean score of membrane type 1 matrix metalloproteinase from normal mucosa to adenoma (P < 0.001), carcinoma in situ (P < 0.006), and invasive cancer (P < 0.009). However, there was no difference in membrane type 1 matrix metalloproteinase expression between the recurrent and nonrecurrent groups of node-negative colon cancer (P = not significant).

CONCLUSIONS

These data suggest that membrane type 1 matrix metalloproteinase expression increases with progression from normal mucosa to invasive adenocarcinoma; however, it cannot be used as a prognostic indicator on which adjuvant therapy is based in node-negative colon cancer because of its failure to predict recurrence in this patient group.

Increased matrix metalloproteinase expression and activation following experimental acute pancreatitis

BACKGROUND

The observation that matrix metalloproteinases (MMPs) are central to tissue remodeling and may contribute to organ failure prompted us to investigate the role of MMPs in acute pancreatitis. We hypothesize that increased expression and activation of MMP-2 and MMP-9 will correlate with organ injury following acute pancreatitis.

METHODS

Acute pancreatitis was induced in five male rats by retrograde infusion of 5% sodium taurocholate into the pancreatic duct. Sham laparotomy was performed on five rats serving as a control. Pancreatitis was confirmed by histology and serum amylase levels. MMP-2 and MMP-9 activity and expression were assayed by gelatin zymography in the lungs and ascitic fluid of each animal. Lung permeability was assayed by Evans blue dye extravasation. Lung activity of MMP-2 and MMP-9 was confirmed by a specific fluorogenic MMP substrate assay.

RESULTS

Lung permeability increased twofold in the animals with severe pancreatitis compared with sham. Analysis of the zymograms from lung homogenate revealed a threefold increase in active MMP-2 in severe pancreatitis compared with sham and no change in MMP-9 activity. Gelatin zymograms of peritoneal fluid from severe pancreatitis animals demonstrated increased levels of active MMP-2 and MMP-9 compared with the sham group. Increases in MMP activity were confirmed by MMP activity assay using a fluorogenic substrate.

CONCLUSIONS

This study demonstrates a correlation between severity of acute pancreatitis and active MMP-2 and MMP-9 levels in the peritoneal fluid and MMP-2 activity in lung homogenate. The MMP-mediated degradation of the basement membrane offers a potential pharmacologic and therapeutic target for halting the final biologic outcome of severe pancreatitis.

Activation of progelatinase A (MMP-2) by neutrophil elastase, cathepsin G, and proteinase-3: a role for inflammatory cells in tumor invasion and angiogenesis

Gelatinase A (MMP-2), a matrix metalloproteinase (MMP) involved in tumor invasion and angiogenesis, is secreted as an inactive zymogen (proMMP-2) and activated by proteolytic cleavage. Here we report that polymorphonuclear neutrophil (PMN)-derived elastase, cathepsin G, and proteinase-3 activate proMMP-2 through a mechanism that requires membrane-type 1 matrix metalloproteinase (MT1-MMP) expression. Immunoprecipitation of human PMN-conditioned medium with a mixture of antibodies to elastase, cathepsin G, and proteinase-3 abolished proMMP-2 activation, whereas individual antibodies were ineffective. Incubation of HT1080 cells with either purified PMN elastase or cathepsin G or proteinase-3 resulted in dose-and time-dependent proMMP-2 activation. Addition of PMN-conditioned medium to MT1-MMP expressing cells resulted in increased proMMP-2 activation and in vitro invasion of extracellular matrix (ECM), but had no effect with cells that express no MT1-MMP. MMP-2 activation by PMN-conditioned medium or purified elastase was blocked by the elastase inhibitor alpha(1)-antitrypsin but not by Batimastat, an MMP inhibitor, showing that elastase activation of MMP-2 is not mediated by MMP activities. The PMN-conditioned medium-induced increase in cell invasion was blocked by Batimastat as well as by alpha(1)-antitrypsin, showing that PMN serine proteinases trigger a proteinase cascade that entails proMMP-2 activation: this gelatinase is the downstream effector of the proinvasive activity of PMN proteinases. These findings indicate a novel role for PMN-mediated inflammation in a variety of tissue remodeling processes including tumor invasion and angiogenesis.

c-abl is required for the development of hyperoxia-induced retinopathy

The requirement for the nonreceptor tyrosine kinase c-abl in the pathogenesis of retinopathy of prematurity (ROP) was examined using the mouse model for ROP and c-abl-deficient mice. Hyperoxia-induced retinal neovascularization was observed in wild-type and heterozygous mice but animals that were homozygous null for c-abl did not develop a vasoproliferative retinopathy in response to hyperoxia. Two gene products, endothelin-1 (ET-1) and vascular endothelial growth factor (VEGF), have been implicated in the pathogenesis of ROP. The mRNA expression of ET-1 and VEGF was assessed in mice maintained in normoxia and in hyperoxia-exposed mice. ET-1 mRNA levels were unchanged in wild-type mice throughout the hyperoxia treatment, suggesting that ET-1 mRNA expression is not regulated by the increase in inspired oxygen. In wild-type mice maintained in room air, VEGF mRNA levels rose threefold from postnatal day 6 (P6) to P17. When wild-type mice were treated with the hyperoxia regimen, a fivefold decrease in VEGF mRNA expression was observed from P7 to P16. However, retinal VEGF expression in hyperoxia-treated homozygous null mice did not decrease and remained at control levels. These data suggest that c-abl is required for the hyperoxia-induced retinal neovascularization and hyperoxia-induced decrease in VEGF mRNA levels.

Topical hepatic hypothermia attenuates pulmonary injury after hepatic ischemia and reperfusion

BACKGROUND

Prolonged periods of hepatic ischemia are associated with hepatocellular injury and distant organ dysfunction in experimental models. Neutrophils (PMN) and tumor necrosis factor (TNF)-alpha have been implicated, mostly because of their local deleterious effects on the hepatocyte after hepatic ischemia and reperfusion (I/R) injury. We hypothesize that topical hepatic hypothermia (THH) reduces ischemia and reperfusion-induced hepatic necrosis, PMN infiltration, TNF-alpha release, and consequent acute pulmonary injury.

STUDY DESIGN

Sprague-Dawley rats (250 to 300g) were evenly divided into three groups: 90 minutes of normothermic (37 degrees C) partial hepatic ischemia (normothermic I/R), 90 minutes of hypothermic (25 degrees C) partial hepatic ischemia (hypothermic I/R), and sham laparotomy (without ischemia). There were six animals in each experimental group per time point unless otherwise specified. Hepatic necrosis and PMN infiltration were evaluated and scored on hematoxylin and eosin-stained liver specimens 12 hours after reperfusion. Serum TNF-alpha levels were determined by ELISA at 0 minutes, 15 minutes, 30 minutes, 1 hour, and 12 hours postreperfusion. Pulmonary PMN infiltration and vascular permeability were measured by myeloperoxidase activity and Evans blue dye extravasation, respectively, to quantitate pulmonary injury 12 hours after reperfusion.

RESULTS

Normothermic I/R results in a significant increase in TNF-alpha at 15 and 30 minutes (p < 0.005), PMN infiltration (p < 0.001), and hepatic necrosis (p < 0.001), compared with sham. Institution of THH reduced peak serum TNF-alpha levels by 54% at 15 minutes (p < 0.005) and by 73% at 30 minutes (p < 0.001) postreperfusion compared with normothermic I/R. Similarly, hepatic PMN infiltration and necrosis at 12 hours were reduced by 60% (p < 0.05) and 47% (p < 0.05), respectively. Myeloperoxidase activity and Evans blue extravasation (measures of acute lung injury) were reduced by 42% and 39%, respectively, with institution of THH compared with animals undergoing normothermic I/R (p < 0.001).

CONCLUSIONS

These results demonstrate that THH protects the liver from ischemia and reperfusion-induced necrosis and PMN infiltration. In addition, THH reduces the serum levels of TNF-alpha and associated pulmonary injury. These data suggest that the ischemic liver is a potential source of inflammatory mediators associated with hepatic ischemia and reperfusion-induced pulmonary injury.

Decreasing length of stay after pancreatoduodenectomy

HYPOTHESIS

Decreased length of stay (LOS) after pancreatoduodenectomy is due to multiple factors, including a lower complication rate and more efficient perioperative care for all patients, with and without complications.

DESIGN

A retrospective review, validation cohort.

SETTING

A single university hospital referral center.

PATIENTS

A consecutive sample of patients undergoing pancreatoduodenectomy from January 9, 1986, to December 21, 1992 (group 1 [n = 104]) and from February 16, 1993, to November 9, 1998 (group 2 [n = 111]).

INTERVENTION

Mann-Whitney test and linear [correction of logistic] regression analysis applied to clinical variables and LOS.

MAIN OUTCOME MEASURES

Difference in median LOS between early and late groups and identification of factors predictive of decreased LOS.

RESULTS

Total LOS decreased between the 2 groups (26 days [range, 13-117 days] vs 15 days [range, 5-61 days]; P<.001), with a decrease in preoperative (4 days [range, 0-28 days] vs 2 days [range, 0-36 days]; P<.001) and postoperative (19 days [range, 11-95 days] vs 12 days [range, 4-58 days]; P<.001) LOS (data given for group 1 vs group 2). Major complications decreased from 49% in group 1 to 25% in group 2 (P<.001). Postoperative LOS decreased for patients with (25 days [range, 15-95 days] vs 20 days [range, 8-58 days]; P = .05) and without (15 days [range, 11-47 days] vs 11 days [range, 4-55 days]; P<.001) major complications (data given for group 1 vs group 2). Multivariate analysis identified age (P = .01), pancreatic fistula (P<.001), delayed gastric emptying (P<.001), biliary complications (P<.001), operative time (P<.005), extra-abdominal infection (P<.005), use of a percutaneous stent (P = .04), and year of operation (P<.001) as independent predictors of total LOS.

CONCLUSION

A reduction in complications in combination with factors leading to a streamlining of perioperative care has contributed to the decreased LOS after pancreatoduodenectomy.

Neutrophil-derived serine proteinases enhance membrane type-1 matrix metalloproteinase-dependent tumor cell invasion

BACKGROUND

Matrix metalloproteinase-2 degrades a variety of basement membrane components and is essential for tumor invasion. We have previously reported that membrane type-1 matrix metalloproteinase (MT1-MMP) cooperates with neutrophil-derived serine proteinases (NDPs; elastase, cathepsin G, protease-3) to activate matrix metalloproteinase-2. We therefore hypothesized that NDPs enhance tumor-cell invasion.

METHODS

Clones of human HT1080 fibrosarcoma cells transfected with MT1-MMP sense (HT-SE) or antisense CDNA (HT-AS) were used. These cells express either high (HT-SE) or extremely low levels (HT-AS) of MT1-MMP relative to nontransfected HT1080 cells (HT-WT). The cells were incubated in the presence or absence of purified NDP, with or without alpha 1-antitrypsin or the MMP inhibitor batimastat. Cell invasion was measured with the use of Boyden chambers with polycarbonate membranes coated with a reconstituted extracellular matrix.

RESULTS

Under control conditions HT-WT and HT-SE cells were 4-fold more invasive than HT-AS cells. The addition of NDP increased HT-WT and HT-SE cell invasion 60% to 100% but had no effect on HT-AS cells. alpha 1-antitrypsin or batimastat did not decrease the baseline invasiveness of HT-WT and HT-SE cells; however, they abrogated the stimulatory effect of NDP.

CONCLUSIONS

HT1080 cell invasion depends on MT1-MMP expression. MT1-MMP overexpression does not increase invasiveness by itself. NDPs increase invasion by MT1-MMP expressing cells by activating matrix metalloproteinase-2.

Expression of Von Willebrand factor, an endothelial cell marker, is up-regulated by angiogenesis factors: a potential method for objective assessment of tumor angiogenesis

von Willebrand factor (vWF), a glycoprotein produced uniquely by endothelial cells and megakaryocytes, is routinely used to identify vessels in tissue sections. Vessel density in tumor specimens, as determined by immuno-histochemical staining for vWF or other endothelial cell markers, is a negative prognostic factor for many solid tumors. vWF is heterogeneously distributed throughout the vasculature, transcriptional control in response to the tissue microenvironment being responsible for local variations in endothelial cell levels of vWF. Here, we report that fibroblast growth factor-2 and vascular endothelial growth factor, potent angiogenesis inducers expressed in a variety of tumors, up-regulate expression of vWF mRNA and protein in cultured endothelial cells with a synergistic effect. Our data support the measurement of vWF mRNA in tumors to detect activated endothelium or angiogenesis. For this purpose, we developed a semi-quantitative RT-PCR for vWF mRNA. Preliminary results obtained with specimens from colon carcinoma and the corresponding normal colonic mucosa showed higher vWF mRNA levels in most tumors than in their normal counterparts. The differences in vWF mRNA levels were much larger than the differences in vessel counts between a tumor and the corresponding normal mucosa, indicating that high vWF mRNA levels in tumors may indeed be an early sign of activation of the endothelium. The rapidity, objectivity, sensitivity and specificity of this technique make it suitable for routine clinical application to identify aggressive, highly angiogenic tumors.

Magnetic resonance imaging with magnetic resonance cholangiopancreatography accurately predicts resectability of pancreatic carcinoma

Accurate preoperative staging of pancreatic malignancy aids in directing appropriate therapy and avoids unnecessary invasive procedures. We evaluated the accuracy of magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) in determining resectability of pancreatic malignancy. Twenty-one patients with suspected pancreatic malignancy underwent dynamic, contrast-enhanced breath-hold MRI with MRCP prior to surgical evaluation. Results of this study were correlated with operative results and pathologic findings. The sensitivity, specificity, and accuracy of MRI with MRCP in detecting a mass, determining the nature of the mass, and predicting lymph node involvement and resectability were determined. MRI with MRCP correctly identified the presence of a pancreatic mass in all 21 of these patients. Following pathologic correlation, it was determined that MRI with MRCP was 81% accurate in determining the benign or malignant nature of the pancreatic mass and 43% accurate in predicting lymph node involvement. In predicting resectability, MRI with MRCP had a sensitivity of 100%, specificity of 83%, positive predictive value of 94%, negative predictive value of 100%, and accuracy of 95%. MRI with MRCP is an accurate, noninvasive technique in the preoperative evaluation of pancreatic malignancy. Information obtained from MRI with MRCP including identification of a mass and predicting tumor resectability may be of value in staging and avoiding unnecessary invasive diagnostic procedures in patients with pancreatic cancer.

Magnetic resonance cholangiopancreatography accurately predicts the presence or absence of choledocholithiasis

Accurate common bile duct (CBD) imaging in patients with biliary calculi is an important determinant of specific therapy. Noninvasive methods to evaluate calculi in the CBD have limited accuracy and rely mainly on ultrasonography and computed tomography. Magnetic resonance cholangiopancreatography (MRCP) is a new noninvasive modality available to evaluate the biliary system. This study was undertaken to assess the accuracy of MRCP in predicting the presence or absence of CBD stones in patients at increased risk for choledocholithiasis. The medical records of 48 patients with a final diagnosis of biliary calculous disease undergoing MRCP between November 1995 and April 1997 were retrospectively reviewed. Three groups were identified: choledocholithiasis (n = 19), gallstone pancreatitis (n 5 11), and uncomplicated cholelithiasis (n = 18). In all patients the presence or absence of CBD calculi, as determined by MRCP, was correlated with the final diagnosis obtained from endoscopic retrograde cholangiopancreatography (ERCP) (n = 19), intraoperative cholangiography (n = 6), CBD exploration (n = 13), or clinical follow-up (n = 10). Sensitivity, specificity, and accuracy of MRCP were determined. The major clinical indications for MRCP in the 48 patients ware abnormal liver function tests followed by hyperamylasemia. Twenty patients were diagnosed with CBD stones and 28 were not. MRCP correctly predicted the presence of CBD stones in 19 of 20 patients and failed to detect CBD stones in one patient with gallstone pancreatitis. MRCP incorrectly predicted the presence of CBD stones in 3 of 28 patients ultimately found to have gallstones and no CBD stones. MRCP correctly predicted the absence of CBD stones in the other 25 patients including 10 patients with gallstone pancreatitis. Overall, MRCP had a sensitivity of 95%, a specificity of 89%, and an accuracy of 92%. MRCP is an accurate, noninvasive test for evaluating the CBD duct for the presence or absence of calculi in patients suspected of having CBD stones. Our data support the use of MRCP in the preoperative evaluation of these patients as findings may influence therapeutic decisions.

Activation of tumor cell matrix metalloproteinase-2 by neutrophil proteinases requires expression of membrane-type 1 matrix metalloproteinase

BACKGROUND

Matrix metalloproteinase-2 (MMP-2), an enzyme involved in tumor invasion, is secreted as an inactive proenzyme and requires interaction with membrane-type 1 MMP (MT1-MMP) for activation. We have previously demonstrated that polymorphonuclear neutrophils (PMNs) release a soluble factor(s) that activates pro-MMP-2. Therefore, we tested the hypothesis that PMN-derived proteinases act in concert with MT1-MMP to activate pro-MMP-2.

METHODS

Human HT-1080 cells transfected with MT1-MMP cDNA (HT-SE) or the corresponding antisense cDNA (HT-AS) or an empty vector (HT-V), which expressed differing levels of MT1-MMP, were incubated with serum-free, human PMN-conditioned medium with or without proteinase inhibitors. The culture supernatants were analyzed by gelatin zymography.

RESULTS

Ht-1080 cells expressing basal (HT-V) or low levels (HT-AS) of MT1-MMP secreted MMP-2 in proenzyme from (72 kd). Ht-1080 cells with high levels of MT1-MMP (HT-SE) secreted pro MMP-2 and a 68 kd intermediate activation product. Addition of PMN-conditioned medium to either HT-SE or HT-V clones resulted in dose-dependent generation of active, 62 kd MMP-2. In contrast, when PMN-conditioned medium was added to HT-AS clones, no MMP-2 activation occurred.

CONCLUSIONS

PMN-derived serine proteinases act in concert with MT1-MMP to activate proMMP-2. This finding indicates a potential role for inflammatory cells in promoting extracellular matrix breakdown during tumor invasion.

Soluble factor(s) released from neutrophils activates endothelial cell matrix metalloproteinase-2

OBJECTIVE

Polymorphonuclear leukocyte (PMN) infiltration and microvascular injury are hallmarks of the tissue remodeling associated with multiple organ failure. These processes require the concerted action of various proteolytic enzymes, including serine and matrix metalloproteinases (MMPs). Matrix metalloproteinase-2 (MMP-2) plays an important role in the turnover of various ECM components, including type IV collagen, fibronectin, and gelatins. Like all MMPs, MMP-2 is secreted as an inactive zymogen (proMMP-2) and activated extracellularly by limited proteolytic cleavage. The physiologic mechanism(s) of proMMP-2 activation remains unclear. This study was designed to characterize the effect of PMNs on the activation of proMMP-2 produced by endothelial cells.

METHODS

PMNs and human umbilical vein endothelial cells (HUVECs) were grown either separately or together for 2-16 h. To evaluate the role of cell-cell contact, cocultures were also established in which the two cell types were separated by a semipermeable polycarbonate membrane. Alternatively, PMN-conditioned medium was added to HUVEC cultures with or without various proteinase inhibitors (aprotinin, 1,10-phenanthroline, Batimastat, E-64, eglin c peptide, or pepstatin A). After incubation, the culture supernatants were analyzed by gelatin zymography to characterize the gelatinases.

RESULTS

HUVECs produce MMP-2 in its inactive (72 kDa) form. PMNs produce high levels of MMP-9 (gelatinase B, 92 kDa) but no MMP-2. Coculture of PMNs with or addition of PMN-conditioned medium to HUVECs results in the production of active (62 kDa) MMP-2. ProMMP-2 activation by PMN-conditioned medium is not blocked by inhibitors of plasmin, cysteine-, acid-, or metalloproteinases.

CONCLUSION

PMNs release a soluble factor that activates endothelial cell MMP-2 through a novel mechanism independent of cell-cell contact and not attributable to the activities of plasmin, cysteine-, acid-, or metalloproteinases. These findings may provide insight into the tissue remodeling that accompanies PMN-mediated microvascular injury.

Cardiopulmonary bypass primes polymorphonuclear leukocytes

Polymorphonuclear leukocyte (PMN) superoxide (.O2-) production has been implicated in the pathogenesis of cardiopulmonary bypass (CPB)-related end organ injury. PMN "priming" has been described as an event which enhances the release of .O2- following a second, activating insult. We hypothesized that PMN priming occurs during CBP and is temporally related to the plasma level of complement (C3a), interleukin (IL)-6, and IL-8. PMNs were isolated from 10 CPB patients pre-bypass (preCPB), 5 min after protamine administration (PROT), and at 6 and 24 h post-CPB. PMN .O2- production was measured by a cytochrome c reduction assay in the presence or absence of either phorbol 12-myristate-13-acetate (PMA, 0.4 microgram/ml) or N-formyl-methionyl-leucyl-phenylalanine (FMLP, 1 microM) and also after priming with 2000 nM platelet-activating factor (PAF) followed by activation with either PMA or FMLP. Plasma levels of C3a, IL-6, and IL-8 were determined by enzyme-linked immunosorbent assay. PMA-activated PMN .O2- production was significantly elevated at 6 h post-CPB compared to pre-CPB levels (11.04 +/- 0.9 vs 7.62 +/- 0.57, P = 0.009), indicating that CPB is associated with in vivo PMN priming. When PMNs were primed in vitro with PAF and then activated with PMA or FMLP, .O2- release at 6 h post-CPB was also significantly greater than pre-CPB levels (16.04 +/- 0.74 vs 12.2 +/- 0.92, P = 0.038; and 17.33 +/- 1.38 vs 13.33 +/- 1.35, P < 0.05), indicating that CPB acts synergistically with PAF to prime PMNs. Levels of C3a rose significantly over pre-CPB levels at PROT (P = 0.001), and IL-6 and IL-8 rose over pre-CPB levels at 6 h post-CPB (P = 0.01 and P = 0.006, respectively). These findings demonstrate that CPB not only directly primes PMNs, but also potentiates priming of PMNs by PAF. This "primed" PMN state, which coincided with the increased plasma levels of inflammatory mediators, may suggest a mechanism of predisposition to organ dysfunction following CPB.