Modification of the inflammatory profile of mesenchymal stem cells using different culture conditions

Aim: Mesenchymal stem cells (MSCs) are pluripotent cells with significant therapeutic potential. The objective of this study was to examine the inflammatory profile of MSCs cultured under different conditions. Methods: MSCs were cultured by three strategies: seeding on an extracellular matrix (ECM), spheroids in static culture and spheroids in a bioreactor. Paracrine factors and CD206, a marker of M2 macrophage phenotype, were measured. Results: MSCs grown as spheroids in a bioreactor produced more IL-6 and IL-8 (p < 0.05). Supernatant collected from spheroids under both culture conditions increased the M2 macrophage phenotype almost twofold. Conclusion: Results indicate that the inflammatory profile of the supernatant collected from MSCs can be modified through culture conditions which has impacts for the future of regenerative medicine.

Watchful Waiting for Ventral Hernias: A Longitudinal Study

Ventral hernias are a common clinical problem. Immediate repair is recommended for most ventral hernias despite significant recurrence rates. This practice may be related to a lack of understanding of the natural history of ventral hernias. The purpose of this study was to determine the natural history of ventral hernias and to determine if watchful waiting is an acceptable and safe option. Forty-one patients with ventral hernias were enrolled in a longitudinal cohort study of watchful waiting. Primary outcomes were functional impairment resulting from hernia disease as measured by the Activities Assessment Scale (AAS) and changes from baseline to two years in the physical and mental component score of the SF-36 Health Survey. Secondary outcomes included complications such as incarceration. Mixed-effects model for repeated measures and Student's t tests were used to evaluate scale performance. The mean age of enrollees was 64 years, and the mean hernia size was 239 cm2. Eleven patients were lost to follow-up, and seven patients died of other causes. All remaining patients were followed for two years. There was one incarceration during the follow-up period. There was no deterioration in the AAS score (baseline vs 24 months = 28 vs 25, P = 0.60). There was deterioration of the physical functioning dimension of the SF-36 (baseline vs 24 months = 40 vs 32, P < 0.01), but the mental functioning dimension was improved (45 vs 51; P = 0.01). Watchful waiting was a safe option for patients in this study with ventral hernias.

Bariatric aftercare and outcomes in the Medicaid population following sleeve gastrectomy

BACKGROUND

Medicaid patients tend to have poor access to care and suffer from more obesity and obesity-related co-morbidities compared to their privately insured counterparts. The impact of Medicaid status on outcomes after laparoscopic sleeve gastrectomy (LSG) is unknown. The aim of this study was to identify factors that influence outcomes following LSG in the adult Medicaid population of Louisiana with particular focus on adherence to bariatric aftercare attendance and access to care.

METHODS

A retrospective review of 63 Medicaid patients undergoing LSG was performed. Demographic data, access to care, weight, co-morbidities morbidity, and mortality were analyzed. Changes in weight and obesity-related co-morbidities were analyzed for patients with ≥12 months of follow-up. Regression analyses were used for estimating the relationships among variables.

RESULTS

The majority of patients were female and non-Caucasian. The mean age was 38.6 years. Morbidity was 16% and mortality was 0%. The average distance traveled to clinic was 71.9 miles. Within the first year only 10% of the patients attended all post-operative clinic visits. A multiple logistic model showed that the only predictor of clinic attendance was increased age. At a mean follow-up of 17.7 months, the mean percent excess body weight loss was 47.2%. Greater pre-surgical weight was the only variable associated with suboptimal weight loss. Improvement or resolution of all major co-morbidities was seen in 65% of patients.

CONCLUSION

Medicaid patients had a poor attendance at bariatric surgery follow up appointments. Since long-term follow-up is critical, we needed to develop strategies that will optimize follow-up in this patient population.

Watchful waiting for ventral hernias: a longitudinal study

Ventral hernias are a common clinical problem. Immediate repair is recommended for most ventral hernias despite significant recurrence rates. This practice may be related to a lack of understanding of the natural history of ventral hernias. The purpose of this study was to determine the natural history of ventral hernias and to determine if watchful waiting is an acceptable and safe option. Forty-one patients with ventral hernias were enrolled in a longitudinal cohort study of watchful waiting. Primary outcomes were functional impairment resulting from hernia disease as measured by the Activities Assessment Scale (AAS) and changes from baseline to two years in the physical and mental component score of the SF-36 Health Survey. Secondary outcomes included complications such as incarceration. Mixed-effects model for repeated measures and Student's t tests were used to evaluate scale performance. The mean age of enrollees was 64 years, and the mean hernia size was 239 cm(2). Eleven patients were lost to follow-up, and seven patients died of other causes. All remaining patients were followed for two years. There was one incarceration during the follow-up period. There was no deterioration in the AAS score (baseline vs 24 months = 28 vs 25, P = 0.60). There was deterioration of the physical functioning dimension of the SF-36 (baseline vs 24 months = 40 vs 32, P < 0.01), but the mental functioning dimension was improved (45 vs 51; P = 0.01). Watchful waiting was a safe option for patients in this study with ventral hernias.

Doublecortin-like kinase 1 exhibits cancer stem cell-like characteristics in a human colon cancer cell line

OBJECTIVE

Colon cancer stem cells (CSCs) are implicated in colorectal cancer carcinogenesis, metastasis, and therapeutic resistance. The identification of these cells could help to develop novel therapeutic strategies. Doublecortin-like kinase 1 (DCLK1) has been viewed as a marker for gastrointestinal stem cells that fuel the self-renewal process, however others view them as a marker of Tuft cells or as an enteroendocrine subtype. The purpose of this study was to use a colon cancer cell line to identify and characterize the stem-like characteristics of the DCLK1+ cell population.

METHODS

To enrich stem-like cells, HCT116 cells (derived from colon adenocarcinomas) were cultured using serum-free media to form spheres under both normal oxygen and hypoxia condition. DCLK1 transcript expression in the adherent parental cells and spheroids was quantified using quantitative real time reverse transcription- polymerase chain reaction [(q)RT-PCR]. DCLK1 protein expression was determined using flow cytometry. Self-renewal capability from adherent parental cells and spheroids was determined using extreme limiting dilution analysis (ELDA).

RESULTS

Under both normal oxygen and hypoxia condition, the adherent parental cells were composed of cells that express low levels of DCLK1. However, spheroids exhibited an increased frequency of cells expressing DCLK1 on both mRNA and protein levels. Cells derived from spheroids also possess stronger self-renewal capability.

CONCLUSIONS

The higher fraction of DCLK1+ cells exhibited by spheroids and hypoxia reflects the stem-like characteristics of these cells. DCLK1 may represent an ideal marker to study and develop effective strategies to overcome chemo-resistance and relapse of colon cancer.

Repair of incisional hernias with biological prosthesis: a systematic review of current evidence

BACKGROUND

No consensus has been reached on the use of bioprosthetics to repair abdominal wall defects. The purpose of this systematic review was to summarize the outcomes from studies describing this use of various bioprosthetics for incisional hernia repair.

METHODS

Studies published by October 2011 were identified through literature searches using EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials.

RESULTS

A total of 491 articles were scanned, 60 met eligibility criteria. Most studies were retrospective case studies. The studies ranged considerably in methodologic quality, with a modified Methodological Index of Nonrandomized Studies score from 5 to 12. Many repairs were performed in contaminated surgical sites (47.9%). At least one complication was seen in 87% of repairs. Major complications noted were wound infections (16.9%) and seroma (12.0%). With a mean follow-up period of 13.6 months the hernia recurrence rate was 15.2%.

CONCLUSIONS

There is an insufficient level of high-quality evidence in the literature on the value of bioprosthetics for incisional hernia repair. Randomized controlled trials that use standardized reporting comparing bioprosthetics with synthetic mesh for incisional hernia repair are needed.

Immunolocalization of DCAMKL-1, a putative intestinal stem cell marker, in normal colonic tissue

Doublecortin and CaM kinase-like-1 (DCAMKL-1) is a microtubule-associated protein kinase which has been recently proposed as a gastrointestinal stem cell marker. The aim of our study was to characterize DCAMKL-1 expression in normal human colon by immunohistochemistry. DCAMKL-1 immunostaining was performed on histologically normal colorectal biopsies from 14 patients. Immunoreactivity was found in over 60% of colonic crypts and was represented by strong cytoplasmic staining, anti-luminal in distribution, and was reminiscent of cytoplasmic orientation of neuroendocrine cells. The highest number (48.5%) of DCAMKL-1 positive cells was found in the first 4 cells from the crypt base. Seventy percent of DCAMKL-1 positive cells were located in the lower third of the crypt, 26% in the middle third and 4% in the upper third. Therefore, in normal colonic mucosa, expression of DCAMKL-1 is not confined to the stem cell compartment. When we compared DCAMKL-1 immunostaining with that of the leucine-rich-repeat-containing G-protein-coupled receptor 5 (Lgr5), an intestinal stem cell marker, and chromogranin-A (CgA), an enteroendocrine cell marker, we found that DCAMKL-1 positive cells co-stained with Lgr5 only at the crypt base, but co-stained with CgA throughout the crypt. Our findings suggest that DCAMKL-1 marks a subset of colorectal stem cells, as well as a subset of enteroendocrine cells.

DCLK1 immunoreactivity in colorectal neoplasia

Introduction

Microtubule-associated doublecortin and CaM kinase-like-1 (DCLK1) is a novel candidate marker for intestinal stem cells. The aim of our study was to assess DCLK1 immunoreactivity in colorectal carcinogenesis and its correlation with prognosis.

Methods

DCLK1 immunostaining was performed in colorectal tissue from 71 patients, including 18 adenomatous polyps, 40 primary adenocarcinomas, and 14 metastatic lesions. Each case was evaluated by a combined scoring method based on the intensity of staining (score 0–3) and the percentage of tissue staining positive (score 0–3). Immunoexpression for DCLK1 was considered as positive when the combined score was 2–6 and negative with a score of 0–1.

Results

Overall, 14/18 (78%) of polyps, 30/40 (75%) of primary adenocarcinomas, and 7/14 (50%) of distant metastases were positive for DCLK1. In adenomatous polyps and primary cancer there was no association between DCLK1 staining score and tumor pathology. However, after curative colorectal cancer resection, patients whose tumor had a high (≥5) combined staining score had increased cancer-specific mortality compared to patients with low (0–4) staining score (hazard ratio 5.89; 95% confidence interval: 1.22–28.47; P = 0.027).

Conclusion

We found that DCLK1 is frequently expressed in colorectal neoplasia and may be associated with poor prognosis. Further studies are necessary to validate the use of DCLK1 as a prognostic marker.

Acute Acalculous Cholecystitis after Gastrointestinal Surgery

Acute acalculous cholecystitis has been identified as a rare but potentially devastating entity after trauma, and burns, as well as in critically ill patients, and in the postoperative period. Gastrointestinal surgery is most frequently implicated in postoperative acute acalculous cholecystitis, especially after gastric and colorectal procedures. Review of the English literature identified 28 articles reporting 76 cases of acute acalculous cholecystitis after gastrointestinal operations, which included a case from Tulane University Medical Center of a 64-year-old man who developed postoperative acute acalculous cholecystitis after elective left hemicolectomy. A total of 52.4 per cent of the patients developed gangrenous acute acalculous cholecystitis, with a mortality rate of 21.1 per cent, much higher than that reported in postoperative calculous cholecystitis. This emphasizes the need for a high level of suspicion and early detection in the postoperative period to avoid devastating consequences.

Acute acalculous cholecystitis after gastrointestinal surgery

Acute acalculous cholecystitis has been identified as a rare but potentially devastating entity after trauma, and burns, as well as in critically ill patients, and in the postoperative period. Gastrointestinal surgery is most frequently implicated in postoperative acute acalculous cholecystitis, especially after gastric and colorectal procedures. Review of the English literature identified 28 articles reporting 76 cases of acute acalculous cholecystitis after gastrointestinal operations, which included a case from Tulane University Medical Center of a 64-year-old man who developed postoperative acute acalculous cholecystitis after elective left hemicolectomy. A total of 52.4 per cent of the patients developed gangrenous acute acalculous cholecystitis, with a mortality rate of 21.1 per cent, much higher than that reported in postoperative calculous cholecystitis. This emphasizes the need for a high level of suspicion and early detection in the postoperative period to avoid devastating consequences.

Circulation of progenitor cells in obese and lean colorectal cancer patients

BACKGROUND

Colorectal cancer (CRC) is a common life-threatening malignancy; risk and progression are elevated in obesity. The purpose of this study was to measure the frequency of circulating CD34-positive endothelial and progenitor cells in the circulation and evaluate their potential values as CRC biomarkers.

METHODS

Blood was collected from 45 patients with CRC and compared with cancer-free control donors. Detection and enumeration of cells was carried out by flow cytometry on the basis of immunophenotypes established for the cell populations of interest: hematopoietic and endothelial circulating progenitor cells, endothelial cells, mesenchymal stromal cells (MSC), and CD34bright leukocytes (CD34b LC). Groups were compared using multivariate regression analysis. Receiver-operating characteristic (ROC) curve analysis was used to evaluate the diagnostic values.

RESULTS

After adjusting for age and body mass index (BMI), the mean frequencies of MSCs and CD34b LCs were significantly higher in the circulation of patients with CRC than in controls. The areas under the ROC curve were 0.77 and 0.82 for MSCs and CD34b LCs, respectively. The frequency of circulating MSCs, but not of the other cell populations, was also found to be significantly higher in the circulation of obese patients with CRC (BMI ≥ 30 kg/m(2)) than in lean patients with CRC and obese controls.

CONCLUSIONS

Increased frequency of MSCs and CD34b LCs in the peripheral blood may represent a new diagnostic marker for CRC.

IMPACT

BMI-dependent changes in circulating MSCs, potentially mobilized from white adipose tissue may reveal their trafficking to tumors, which could be one of the mechanistic links between obesity and cancer progression.

Influence of BMI on level of circulating progenitor cells

Obesity complicates a number of diseases through mechanisms that are poorly defined. Mobilization and recruitment of progenitor cells to pathological sites is an important factor in disease progression. Here, we analyzed the influence of obesity on the systemic circulation of CD34(+) cell populations and correlated frequencies of cells displaying previously established cell marker signatures with the BMI. Comparative analysis of peripheral blood mononuclear cells (PBMC) from 12 nonobese (BMI <30 kg/m(2)) and 14 obese (BMI >30 kg/m(2)) disease-free donors by flow cytometry revealed that obesity is associated with a fivefold increased frequency of circulating progenitor cells (CPC), a population consisting of hematopoietic and endothelial precursors. Our data also indicate that obesity is associated with increased frequency of circulating mesenchymal stromal progenitor cells (MSC). In contrast, the frequencies of mature endothelial cells (EC) and CD34-bright leukocytes are unaffected by obesity. Combined, our results indicate that obesity promotes mobilization of progenitor cells, which may have clinical relevance.

Combination of oral non-absorbable and intravenous antibiotics versus intravenous antibiotics alone in the prevention of surgical site infections after colorectal surgery: a meta-analysis of randomized controlled trials

BACKGROUND

Oral non-absorbable antibiotics work by decreasing intraluminal bacterial content after mechanical bowel preparation. The advantage of adding oral non-absorbable antibiotics to intravenous antibiotics to decrease surgical site infection (SSI) after colorectal surgery is not well known. We conducted a meta-analysis of randomized controlled trials (RCT) comparing the effectiveness of combined oral non-absorbable and intravenous antibiotics versus intravenous antibiotics alone in reducing the incidence of SSI following colorectal surgery.

METHOD

We included RCT comparing a combination of oral non-absorbable antibiotics and intravenous antibiotics to intravenous antibiotics alone in order to prevent SSI after colorectal surgery. Outcomes assessed included postoperative infectious complications, such as surgical wound infections (SWI) defined as a combination of superficial and deep SSI, organ-space infections and anastomotic dehiscence.

RESULTS

Sixteen RCT published between 1979 and 2007 were included in the meta-analysis. The overall analyses indicated that patients randomly assigned to an oral non-absorbable antibiotic in addition to an intravenous antibiotic had a reduced risk of SWI (RR: 0.57 [95% CI: 0.43-0.76], p = 0.0002) compared with participants receiving only intravenous antibiotics. The use of oral non-absorbable antibiotics in addition to intravenous antibiotics had no significant effect on organ-space infections (RR: 0.71 [95% CI: 0.43-1.16], p = 0.2) or the risk of anastomotic leak (RR: 0.63 [95% CI: 0.28-1.41], p = 0.3).

CONCLUSION

Our meta-analysis shows that a combination of oral non-absorbable antibiotics and intravenous antibiotics significantly lowers the incidence of SWI compared with intravenous antibiotics alone. In light of our results, the use of oral non-absorbable antibiotics in colorectal surgery should be encouraged.

Colonic large cell neuroendocrine carcinoma obscured by an initial diagnosis of diverticulitis

Large cell neuroendocrine carcinomas are rare and aggressive colorectal malignancies that have a dismal prognosis. We present the following case of a patient who presented with signs and symptoms of diverticulitis. After failure of medical management, surgical intervention revealed a poorly differentiated adenocarcinoma with a component of large cell neuroendocrine carcinoma.

The effect of bacterial infection on the biomechanical properties of biological mesh in a rat model

BACKGROUND

The use of biologic mesh to repair abdominal wall defects in contaminated surgical fields is becoming the standard of practice. However, failure rates and infections of these materials persist clinically. The purpose of this study was to determine the mechanical properties of biologic mesh in response to a bacterial encounter.

METHODS

A rat model of Staphylococcus aureus colonization and infection of subcutaneously implanted biologic mesh was used. Samples of biologic meshes (acellular human dermis (ADM) and porcine small intestine submucosa (SIS)) were inoculated with various concentrations of methicillin-resistant Staphylococcus aureus [10(5), 10(9) colony-forming units] or saline (control) prior to wound closure (n = 6 per group). After 10 or 20 days, meshes were explanted, and cultured for bacteria. Histological changes and bacterial recovery together with biomechanical properties were assessed. Data were compared using a 1-way ANOVA or a Mann-Whitney test, with p<0.05.

RESULTS

The overall rate of staphylococcal mesh colonization was 81% and was comparable in the ADM and SIS groups. Initially (day 0) both biologic meshes had similar biomechanical properties. However after implantation, the SIS control material was significantly weaker than ADM at 20 days (p = 0.03), but their corresponding modulus of elasticity were similar at this time point (p>0.05). After inoculation with MRSA, a time, dose and material dependent decrease in the ultimate tensile strength and modulus of elasticity of SIS and ADM were noted compared to control values.

CONCLUSION

The biomechanical properties of biologic mesh significantly decline after colonization with MRSA. Surgeons selecting a repair material should be aware of its biomechanical fate relative to other biologic materials when placed in a contaminated environment.

Clinical significance of magnetic resonance imaging findings in rectal cancer

Staging of rectal cancer is essential to help guide clinicians to decide upon the correct type of surgery and determine whether or not neoadjuvant therapy is indicated. Magnetic resonance imaging (MRI) is currently one of the most accurate modalities on which to base treatment decisions for patients with rectal cancer. MRI can accurately detect the mesorectal fascia, assess the invasion of the mesorectum or surrounding organs and predict the circumferential resection margin. Although nodal disease remains a difficult radiological diagnosis, new lymphographic agents and diffusion weighted imaging may allow identification of metastatic nodes by criteria other then size. In light of this, we have reviewed the literature on the accuracy of specific MRI findings for staging the local extent of primary rectal cancer. The aim of this review is to establish a correlation between MRI findings, prognosis, and available treatment options.

Diminished organelle motion in murine Kupffer cells during the erythrocytic stage of malaria

Parasitized erythrocytes are ingested by murine hepatic macrophages during malaria infection. We non-invasively monitored how this altered the motion of intracellular phagosomes in Kupffer cells using magnetometry. Submicrometric γFe(2)O(3) particles were injected prior to malaria infection. They were cleared from the blood, primarily by Kupffer cells, and retained within their phagosomes. The mice were periodically magnetized. After removing this external magnet, the aligned iron particles created a remnant magnetic field (RMF) which then decayed (relaxation), reflecting the motion of particle-containing phagosomes. After baseline measurements of relaxation, the mice were injected intravenously with Plasmodium chabaudi-parasitized or normal murine red blood cells (RBCs). During the next 15 days, relaxation measurements, parasitaemia and haematocrit values were monitored. At 6 days post injection with 3 × 10(7) parasitized RBCs, relaxation rates had decreased. At this time, all mice had parasitaemias greater than 58 per cent and haematocrits less than 20 per cent. At day 7, while the parasitaemias were declining, the rate of relaxation continued to decrease. Throughout the experiment, relaxation remained constant in animals injected with normal RBCs. Electron microscopy revealed Kupffer cells filled with damaged and parasitized erythrocytes, and haemoglobin degradation pigment. We conclude that ingestion and metabolism of parasitized erythrocytes by liver macrophages during malaria infection decreases their organelle motion with likely consequences of compromised host defences.

Umbilical herniorrhaphy reinforced with biologic mesh

The true recurrence rate after umbilical hernia repair in not known. After simple closure, the reported rate of recurrence in the literature is as high as 54 per cent. With synthetic mesh repair, the recurrence rates are lowered to less than 10 per cent. However, synthetic mesh is associated with complications such as enterocutaneous fistula and mesh infections. This preliminary study looks at the safety and effectiveness of biologic extracellular matrix mesh reinforcement in the repair of umbilical hernias. We retrospectively reviewed all patients who underwent repair of an umbilical hernia defect (2-3 cm) with primary approximation of the margins and reinforced using a biologic mesh placed beneath the umbilical fascia from 2007 to 2009. Demographic data were collected. Patients were followed prospectively at 2 weeks, 8 weeks, 6 months, and 1 year. Data were reviewed for postoperative complications, hernia recurrence, and patient satisfaction. During the study period, 16 patients completed the 1 year follow-up. There were 10 men and six women. Ages ranged from 28 to 75 years with a mean age of 47.6 years. The hernias were 2 to 3 cm in size. Complications were minimal. Overall patient satisfaction with the procedure was high. There were no mesh infections. During a mean follow-up of 12 months, only one patient had recurrent hernia (6%). This preliminary evaluation shows promise for an alternative treatment of umbilical hernias using biologic extracellular matrix mesh added as an underlay to reinforce a primary closure. The biologic mesh has a low incidence of infection and complications and results in high patient satisfaction. This preliminary study begs for a randomized, prospective evaluation with long-term follow-up.

Umbilical Herniorrhaphy Reinforced with Biologic Mesh

The true recurrence rate after umbilical hernia repair in not known. After simple closure, the reported rate of recurrence in the literature is as high as 54 per cent. With synthetic mesh repair, the recurrence rates are lowered to less than 10 per cent. However, synthetic mesh is associated with complications such as enterocutaneous fistula and mesh infections. This preliminary study looks at the safety and effectiveness of biologic extracellular matrix mesh reinforcement in the repair of umbilical hernias. We retrospectively reviewed all patients who underwent repair of an umbilical hernia defect (2-3 cm) with primary approximation of the margins and reinforced using a biologic mesh placed beneath the umbilical fascia from 2007 to 2009. Demographic data were collected. Patients were followed prospectively at 2 weeks, 8 weeks, 6 months, and 1 year. Data were reviewed for postoperative complications, hernia recurrence, and patient satisfaction. During the study period, 16 patients completed the 1 year follow-up. There were 10 men and six women. Ages ranged from 28 to 75 years with a mean age of 47.6 years. The hernias were 2 to 3 cm in size. Complications were minimal. Overall patient satisfaction with the procedure was high. There were no mesh infections. During a mean follow-up of 12 months, only one patient had recurrent hernia (6%). This preliminary evaluation shows promise for an alternative treatment of umbilical hernias using biologic extracellular matrix mesh added as an underlay to reinforce a primary closure. The biologic mesh has a low incidence of infection and complications and results in high patient satisfaction. This preliminary study begs for a randomized, prospective evaluation with long-term follow-up.

Adipose tissue-derived progenitor cells and cancer

Recruitment of stem cells and partially differentiated progenitor cells is a process which accompanies and facilitates the progression of cancer. One of the factors complicating the clinical course of cancer is obesity, a progressively widespread medical condition resulting from overgrowth of white adipose tissue (WAT), commonly known as white fat. The mechanisms by which obesity influences cancer risk and progression are not completely understood. Cells of WAT secret soluble molecules (adipokines) that could stimulate tumor growth, although there is no consensus on which cell populations and which adipokines are important. Recent reports suggest that WAT-derived mesenchymal stem (stromal) cells, termed adipose stem cells (ASC), may represent a cell population linking obesity and cancer. Studies in animal models demonstrate that adipokines secreted by ASC can promote tumor growth by assisting in formation of new blood vessels, a process necessary for expansion of tumor mass. Importantly, migration of ASC from WAT to tumors has been demonstrated, indicating that the tumor microenvironment in cancer may be modulated by ASC-derived trophic factors in a paracrine rather than in an endocrine manner. Here, we review possible positive and adverse implications of progenitor cell recruitment into the diseased sites with a particular emphasis on the role in cancer progression of progenitors that are expanded in obesity.

Body image and health locus of control among male patients with incisional hernias

Incisional hernias form after surgery through incision sites and can enlarge over time. Relations between body image (BI) and health locus of control (HLC) were investigated in male patients undergoing evaluation for incisional hernia repair (n=32) and non-hernia controls (n=34). Analyses revealed that patients with incisional hernias reported significantly less satisfaction with general appearance and appearance of the mid-torso than non-hernia controls. Although HLC beliefs did not vary by group, post hoc analyses revealed several significant relations between BI factors and HLC beliefs. Results suggest that poor BI is a significant area of concern among patients with incisional hernias.

Early predictors of anastomotic leaks after colectomy

BACKGROUND

An anastomotic leak after colorectal surgery is associated with significant morbidity and decreased survival. Our aim was to identify the early predictors of anastomotic leaks.

METHODS

The records of patients undergoing restorative resection for colorectal disease from January 2000 to November 2005 were reviewed. Demographics, clinical events, and laboratory parameters were recorded.

RESULTS

A total of 311 patients were included. An anastomotic leak was identified in 25 patients (8%). A leak was suspected and diagnosis confirmed at a mean of 10+/-1 days postoperatively. More respiratory and neurological events occurred in patients with an anastomotic leak (p<0.001). These events occurred early in the postoperative course and were usually the first signs and symptoms of a leak. More patients with a leak had absence of bowel activity by postoperative day 6 compared to patients without a leak (p<0.0001). Elevations of the white blood cell count or temperature were a late finding.

CONCLUSION

The earliest clinical predictors of an anastomotic leak are pulmonary and/or neurological. Awareness of these findings might help in early diagnosis and treatment of an anastomotic leak.

More than 150 consecutive open umbilical hernia repairs in a major Veterans Administration Medical Center

BACKGROUND

The purpose of this study was to determine the rate of surgical site infection for open elective umbilical hernia repairs and to identify the factors related to an increased risk of infection and/or recurrence.

METHODS

A retrospective analysis of 152 open elective umbilical hernia repairs between 2003 and 2007 was performed.

RESULTS

Overall, 19% of repairs became infected. Both high ASA classification (P = .01) and mesh repair (P = .01) significantly predicted wound infection, whereas age >60 years, body mass index >30, smoking, immunosuppression, diabetes, and hernia size did not. Only 2 of 17 infected mesh repairs required removal of the mesh. The recurrence rate was 1.5% for mesh and 9.2% for suture repairs.

CONCLUSIONS

Umbilical hernia repair is associated with a high rate of infection, and most superficial mesh infections can be treated with antibiotics alone. In addition, mesh repair of umbilical hernias decreased the rate of recurrence but increased the risk of infection compared with suture repairs.

Splenic artery embolization and endovascular stapler integrity in a porcine model

Splenic artery embolization is often used before laparoscopic splenectomy in cases of splenomegaly to reduce blood loss and facilitate the procedure. The aim of this study was to examine the general reliability of endovascular staplers when fired at the site of embolization coil deployment using a porcine model. Ex vivo and in vivo experiments were conducted on porcine abdominal aortas, which are similar in diameter to those of the splenic artery in the human. When the endovascular staplers were fired across the porcine vessels at the area of embolization coil deployment ex vivo, the staple lines all failed. In contrast, in vivo, the staple lines remained intact with no bleeding despite resistance imposed by the intravascular coils. Despite consistent failure in the ex vivo studies, in vivo all staple lines held and permitted safe transection of the vessel. We presume that the hemostatic properties of the coils caused sufficient thrombosis in this model, which mimics the clinical situation, to permit division of the previously embolized splenic vessel.

Splenic Artery Embolization and Endovascular Stapler Integrity in a Porcine Model

Splenic artery embolization is often used before laparoscopic splenectomy in cases of splenomegaly to reduce blood loss and facilitate the procedure. The aim of this study was to examine the general reliability of endovascular staplers when fired at the site of embolization coil deployment using a porcine model. Ex vivo and in vivo experiments were conducted on porcine abdominal aortas, which are similar in diameter to those of the splenic artery in the human. When the endovascular staplers were fired across the porcine vessels at the area of embolization coil deployment ex vivo, the staple lines all failed. In contrast, in vivo, the staple lines remained intact with no bleeding despite resistance imposed by the intravascular coils. Despite consistent failure in the ex vivo studies, in vivo all staple lines held and permitted safe transection of the vessel. We presume that the hemostatic properties of the coils caused sufficient thrombosis in this model, which mimics the clinical situation, to permit division of the previously embolized splenic vessel.

Abdominal wall repair using human acellular dermis

BACKGROUND

The surgical repair of abdominal wall defects that cannot be closed primarily in contaminated fields is a difficult problem. The use of nonabsorbable synthetic materials usually is contraindicated in this setting because of the risk for colonization and chronic infection of the mesh. In this study we sought to determine the safety and efficacy of implanted human acellular dermal graft for abdominal wall reconstruction.

METHODS

The records of all patients (n = 20) who underwent a repair of an abdominal wall defect with human acellular dermal graft at a Veteran Affairs hospital were reviewed retrospectively. Patient demographics, complications, and hernia recurrence were recorded.

RESULTS

There were 15 perioperative complications in 11 patients: 6 graft dehiscences, 1 evisceration, 2 postoperative intra-abdominal bleeds, 5 bacterial graft infections, and 1 death. Patients with heart disease, American Society of Anesthesiologists classification of 4, and/or dirty wounds were more likely to have perioperative complications. The median follow-up period was 9.4 months (range, 2-16 mo), during which 6 hernia recurrences were noted.

CONCLUSIONS

Human acellular dermis use is safe in abdominal wall reconstructions in contaminated surgical wounds.

Improved outcomes with the Prolene Hernia System mesh compared with the time-honored Lichtenstein onlay mesh repair for inguinal hernia repair

BACKGROUND

Inguinal hernia repairs are commonly performed operations. Recently, Neumayer et al examined the gold standard Lichtenstein onlay mesh repair (LMR) against laparoscopic inguinal hernia repair and showed that the recurrence rates are higher for laparoscopic mesh repairs when compared with the open onlay mesh repair (laparoscopic = 10.1% versus open = 4.9%). In 1998, the Prolene Hernia System (PHS) mesh, consisting of an onlay and an underlay patch attached with a connector, was introduced as an option for tension-free open repair of inguinal hernias combining the benefits of a posterior and anterior repair from an open approach. Our objective was to evaluate the PHS mesh repair versus the LMR for inguinal hernias. We hypothesized that the recurrence rate of PHS mesh would be lower compared with the LMR with overall similar complication rates.

METHODS

PHS mesh hernia repairs performed from January 2003 to July 2005 and LMR repairs from January 2000 to July 2002 were included. Demographic data such as age, race, and gender as well as comorbid conditions such as chronic obstructive pulmonary disease, congestive heart failure, previous myocardial infarction, diabetes, hypertension, prostatism, and chronic cough were collected. Complications such as cord injury, seroma, hematoma, urinary retention, urinary tract infection, orchitis, and wound infection were recorded. Recurrences in each group were also recorded. A student t test and chi-square analysis were used for statistical analysis.

RESULTS

Six hundred twenty-two charts were reviewed during the 2 time periods (PHS mesh = 321, LMR = 302). The median follow-up for the study was 17 months. There was no significant difference with regards to age, race, gender, or comorbidities between the 2 groups. Overall, there was a trend toward decreased complications in the PHS mesh group compared with the LMR group (PHS mesh = 17%, LMR = 23%, P = .07), with a significant difference in the hematoma/seroma rates (PHS mesh = 6.9%, LMR = 12.6%, P = .015). Finally, there was a significant decrease in the recurrence rate for the PHS mesh group when compared with the LMR group (PHS mesh = 0.6%, LMR = 2.7%, P = .04).

CONCLUSION

Our study shows, during a median follow-up of 17 months, improved outcomes by using the PHS mesh compared with the gold standard Lichtenstein onlay mesh for inguinal hernias with significantly lower recurrence rates. Additionally, in the PHS mesh group, there was a trend toward decreased overall complication rates with significantly less seroma/hematoma rates. Therefore, the PHS mesh repair may represent a superior alternative for the repair of inguinal hernias.

Abdominal wall reconstruction using biological tissue grafts: present status and future opportunities

Surgeons often encounter the challenge of treating acquired abdominal wall defects following abdominal surgery. The current standard of practice is to repair most defects using permanent synthetic mesh material. Mesh augments the strength of the weakened abdominal wall fascia and enables the hernia repair to be performed in a tension-free manner. However, there is a risk of acute and/or chronic infection, fistula formation and chronic abdominal wall pain with the use of permanent mesh materials, which can lead to more complex operations. As a means to avoid such problems, surgeons are turning increasingly to the use of xenogenic and allogenic materials for the repair of abdominal wall defects. Their rapid evolution and introduction into the clinical operating room is leading to a new era in abdominal wall reconstruction. There are promising, albeit limited, clinical data with short-term follow-up for only a few of the many biological tissue grafts that are being promoted currently for the repair of abdominal hernias. Additional clinical studies are required to better understand the long-term efficacy and limitations of these materials.

Decellularized human cadaveric dermis provides a safe alternative for primary inguinal hernia repair in contaminated surgical fields

BACKGROUND

Repair options for inguinal hernias in contaminated surgical fields include local tissue repair or mesh repair. The former is associated with higher hernia recurrence rates. The latter generally is avoided because of an unacceptably high infection rate. AlloDerm (Lifecell Corp., Branchburg, NJ) can potentially provide a strong repair resistant to infection. The aim of our study was to evaluate if AlloDerm provides a safe alternative for inguinal hernia repair in contaminated surgical fields.

METHODS

We retrospectively reviewed the medical records of all patients who underwent inguinal hernia repair with AlloDerm from December 2004 to April 2006. Demographics, risk factors, perioperative data, and recurrence rates were evaluated.

RESULTS

Twelve patients with contaminated surgical fields underwent inguinal hernia repair with AlloDerm. Serious perioperative complications occurred in only 1 patient. Two patients developed superficial wound infections (treated conservatively). There were no mortalities. No hernia recurrence has been documented with a follow-up period of 3 to 17 months (median, 9 mo).

CONCLUSIONS

AlloDerm provides a safe alternative for inguinal hernia repair in contaminated surgical fields.

Epidemiology of exposure to blood borne pathogens on a surgical service

BACKGROUND

The goal of this study was to analyze the type and mechanism of blood exposure injuries on the surgical service in order to develop appropriate preventative strategies.

METHODS

A retrospective review of all exposure injuries affecting members of the operative care line at a single teaching institution between December 2002 and December 2005 was performed.

RESULTS

Of 98 exposure injuries on the surgical service, only 17 (17%) were inflicted by hollow-bore needles. Seventy-four (76%) of these reported injuries occurred in the operating room (OR) and 24 (24%) occurred in other clinical areas. Sharps injuries accounted for 69 (93%) of OR injuries and were inflicted by suture needles (n = 37, 50%), hollow-bore needles (n = 7, 9%), and sharp instruments (n = 25, 34%). Mucocutaneous contamination accounted for 5 (7%) of the OR exposures. Professionals most frequently injured were residents (n = 43, 44%), followed by nurses (n = 28, 29%), students (n = 17, 17%) and other healthcare workers (n = 10, 10%).

CONCLUSIONS

Blood exposure prevention strategies should be directed at safety within the surgical field and focused beyond hollow-bore needle stick injuries to include education, mentoring, and competency training.

Laparoscopic splenectomy: present status and future perspective

Laparoscopic splenectomy has become widely accepted as the approach of choice for the surgical treatment of benign and malignant hematologic diseases. Advances in technology have led to better outcomes for the procedure, and have allowed surgeons to apply the technique to disease processes that were at one time felt to be contraindications to laparoscopic splenectomy. However, challenges still remain. There is a steep learning curve associated with the procedure. The development of cost-effective laparoscopic simulators to target the skills required for laparoscopic splenectomy and other laparoscopic procedures is essential. The advent of devices which isolate and seal the large blood vessels that surround the spleen have reduced intra-operative bleeding and minimized conversions to open splenectomy. Improvements in optics and instrumentation, as well as robotic technology, will continue to define the frontier of minimally invasive surgery, and further facilitate the acceptance of laparoscopic splenectomy for the treatment of benign and malignant hematologic diseases.

Infiltration of suture sites with local anesthesia for management of pain following laparoscopic ventral hernia repairs: a prospective randomized trial

BACKGROUND

Postoperative pain control after laparoscopic ventral hernia repairs remains a significant clinical problem. We sought to determine the pain-sparing efficacy of local anesthetic infiltrated into the abdominal wall wounds created by the placement of transabdominal sutures used to ensure adequate fixation of the mesh during laparoscopic ventral hernia repair.

METHODS

Patients undergoing laparoscopic ventral/incisional hernia repair were randomized to receive local anesthesia (0.25% bupivacaine with epinephrine) into all layers of the abdominal wall to the level of the parietal peritoneum at suture fixation sites immediately before suture placement (Group I; n=9) or no local anesthesia (Group II, control; n=9). The anesthetic technique was otherwise standard for both groups. Postoperatively, pain was assessed with a 10-point visual analogue scale (VAS) at 1, 2, 4, and 24 hours. Analgesic use and hospital stay were also recorded.

RESULTS

The groups were similar in age, sex, ASA, and size of hernia defect. The operative times were not statistically different between the 2 groups (Group I, 118+/-12 minutes; Group II, 144+/-21 minutes; P>0.05). Group I had a statistically significant decrease in the pain scores compared with Group II (2.2+/-0.8 vs. 6.4+/-0.9; P<0.05) at 1 hour postoperatively. At 2 and 4 hours, the mean pain scores were decreased but not statistically different. Similarly, the cumulative consumption of pain medication at 1, 2, and 4 hours postoperatively as well as the average hospital stay (Group I, 2.0+/-0.4; Group II, 2.4+/-0.4 days) were lower but not statistically significant in patients in Group I compared with those in Group II.

CONCLUSION

This small, randomized study demonstrates that infiltration of suture fixation sites is effective in reducing early postoperative pain but not analgesic consumption following laparoscopic incisional and ventral hernia repairs. A larger study is required to investigate this strategy on later postoperative pain and hospital stay.

Length of human immunodeficiency virus disease and not immune status is a risk factor for development of anal carcinoma

BACKGROUND

The anal epithelium is subject to dysplastic change in patients with human immunodeficiency virus (HIV). We sought to determine if the duration of HIV disease or the patient's immune status were associated with the development of anal carcinoma.

METHODS

HIV-positive patients diagnosed with anal neoplasms were reviewed. Statistical analysis was performed via an unpaired Student t test and the Fisher exact test.

RESULTS

Fourteen patients were identified, 7 with anal intraepithelial neoplasms (group 1) and 7 with anal carcinoma (group 2). Human papillomavirus was detected in 100% of patients in group 1 and in 67% of patients in group 2. There was no significant difference in the level of immunosuppression as assessed by the CD4 counts (266.9 +/- 48.5 vs. 274.7 +/- 92.0 cell/c microl; P = .94) and viral loads (19,243 +/- 18,034 vs. 67,140 +/- 39,570 RNA/mL; P = .29) between groups 1 and 2, respectively. Group 2 had been HIV positive for a significantly longer period of time (12.6 +/- 2.3 y) compared with group 1 (5.9 +/- 2.0 y, P = .05).

CONCLUSIONS

The most significant factor for the development of invasive anal carcinoma in patients with HIV is duration of disease. As a result of improved long-term survival secondary to new HIV therapy, anal invasive carcinoma will become an increasing problem.

Modulation of macrophage nitric oxide production by prostaglandin D2

BACKGROUND

Nitric oxide and prostaglandins readily become activated in response to inflammatory events. The overproduction of nitric oxide is detrimental to the host. The present study was conducted to examine whether prostaglandin D(2) (PGD(2)) modulates nitric oxide production in macrophages in response to an inflammatory stimulus.

METHODS

Cultures of RAW 264.7 murine macrophages were exposed to Escherichia coli lipopolysaccharide (LPS, 0.01 and 1.0 microg/ml) before and after exposure to PGD(2) (0.01 to 10 nmol). After 24-h incubation, supernatants were collected and nitrite was quantitated by Greiss reaction as a measure of nitric oxide synthesis. Inducible nitric oxide synthase (iNOS) protein was measured by Western blot analysis.

RESULTS

Macrophages exposed to 0.01 and 1.0 microg/ml LPS produced 8.3 +/- 0.2 and 15.0 +/- 1.4 nmol/1.1 x 10(6) cells/24 h of nitrite, respectively. The simultaneous addition of PGD(2) with LPS inhibited nitrite production in a dose-dependent fashion and suppressed iNOS protein expression. A strong time effect was also exhibited when macrophages were incubated with PGD(2) 1 hour before as compared to 7 hours after the addition of LPS (0.01 or 1.0 microg/ml), indicating that the earlier the time PGD(2) was added to the culture media, the greater the inhibition. Prostaglandin D(2) had the capacity to block nitrite synthesis even when added as much as 7 hours after an LPS challenge. Blocking endogenous prostaglandins, using indomethacin (10 microM), suppressed nitrite production.

CONCLUSION

Exogenous PGD(2) caused dose- and time-dependent decreases in LPS-stimulated nitrite production by RAW 264.7 macrophages by hindering iNOS protein expression. Conversely, the endogenous prostaglandins released by these same cells in response to an LPS challenge stimulated nitrite production, which may consequently dampen the inhibitory actions of exogenous PGD(2).

Management of gallstones

Many patients with gallstones can be managed expectantly. Generally, only persons with symptoms related to the presence of gallstones (e.g., steady, nonparoxysmal pain lasting four to six hours located in the upper abdomen) or complications (such as acute cholecystitis or gallstone pancreatitis) warrant surgical intervention. Biliary pain is alleviated by cholecystectomy in the majority of cases. Laparoscopic cholecystectomy is considered the most cost-effective management strategy in the treatment of symptomatic gallstones. Medical management strategies are mostly palliative and are not widely supported. Patients with longer-lasting biliary pain, in combination with abdominal tenderness, fever, and/or leukocytosis, require an ultrasound evaluation to help establish a diagnosis of acute cholecystitis. Once a patient is diagnosed, having cholecystectomy early in the course of the disease can significantly reduce the hospital stay.

Role of fibronectin in pancreatitis-associated lung injury

Acute pancreatitis (AP) in humans can lead to increased vascular permeability in the lungs and respiratory failure. Fibronectin plays an important role in maintaining the structural integrity of the pulmonary epithelium and endothelium. However, its importance in pancreatitis-associated lung injury has not been defined. AP was produced by infusing caerulein (5 ug/kg/hr) in rats for 8 or 24 hr. Lung injury was assessed histologically and by determining lung microvascular permeability by bronchoalveolar lavage (BAL) analysis. Organ distribution of a target particle given intravenously was determined by the vascular clearance of magnetic iron oxide particles. Plasma fibronectin was measured by the enzyme-linked immunosorbent assay technique. After 8 hr of cerulein infusion, serum amylase increased 8-fold. Pancreatitis correlated with lung injury. BAL at 8 hr showed a 90% increase (P < 0.05) in albumin levels. Histological analysis at 8 hr revealed an increased number of leukocytes within the lungs. By 8 hr, plasma fibronectin significantly decreased 25% (P < 0.05) and the pulmonary uptake of iron oxide increased 111% (P < 0.05). By 24 hr, these effects had nearly resolved. These results indicate that decreases in serum fibronectin and increases in pulmonary leukocyte margination during acute pancreatitis may compromise the integrity of the air-blood barrier and also increase the pulmonary uptake of circulating pathogenic materials, thus making lung injury more likely.

Vaccinia virus-induced inhibition of nitric oxide production

BACKGROUND

The role of nitric oxide (NO) in the host defense against viruses has not been well defined. Several studies have implicated NO as responsible for the destruction of a variety of viruses. However, others have reported that certain viruses can impair the ability of macrophages to produce NO. This study was initiated to determine the ability of macrophages to produce NO in response to vaccinia virus infection.

METHODS

RAW 264.7 murine macrophages in minimum essential medium were exposed to virus-containing supernatants for 1 h before stimulation with Escherichia coli lipopolysaccharide (LPS, 0.001 and 1.0 microg/ml). After further 24-h incubations, nitrite concentration, cell viability, and inducible nitric oxide synthase (iNOS) were quantitated.

RESULTS

The viral preparation alone did not stimulate nitric oxide synthesis (measured as nitrite) by macrophages. However, macrophages exposed to 0.001 and 1.0 microg/ml LPS produced 7.7 +/- 0.6 and 16.6 +/- 0.8 nmole/1.1 x 10(6) cells/24-h nitrite, respectively. Production of nitrite caused cell death. Macrophages incubated with vaccinia virus prior to exposure to LPS resulted in a dose-dependent decrease in nitrite production. An 80% inhibition of nitrite was noted when macrophages were exposed to vaccinia virus (m.o.i. 10(-4)) plus LPS (1.0 microg/ml) (P < 0.05). Further study showed that this inhibition was not associated with changes in cell viability or substrate availability, but was associated with a marked reduction in iNOS protein. When the virus was inactivated with UV-irradiation, the same incubation caused a 46% inhibition of nitrite production (P < 0.05 vs active virus). However, this effect occurred without altering the quantity of iNOS protein.

CONCLUSION

These results indicate that active vaccinia virus inhibits the ability of stimulated macrophages to produce NO by hindering iNOS protein expression. Because live viral particles were not entirely required for this inhibition, it is possible that by products of viral infection, such as soluble viral proteins, may also be responsible for this effect.

Cosmetic approach to anterior mediastinal masses

A new approach for the removal of thymic tissue or any anterior mediastinal pathology is described. It uses a novel low U-shaped skin incision combined with a J-shaped upper mini-sternotomy. This technique was designed to provide wide exposure of the mediastinum and to be cosmetically appealing. Our study included 12 patients, 4 with a preoperative diagnosis of myasthenia gravis. There were no operative mortality and three complications. This procedure allows for complete removal of all thymic tissue under direct vision, and is less invasive that full sternotomy.

The surgical abdomen associated with cocaine abuse

Cocaine use is common and is associated with gastrointestinal complications that can present as a surgical abdomen. We report a case of a previously healthy 25-year-old man who presented to the Emergency Department with severe abdominal pain and vomiting after using IV cocaine. Exploratory celiotomy revealed massive free intraperitoneal (IP) clotted blood with no evidence of underlying pathology. This unusual case underscores the possibility of life-threatening hemorrhage in cocaine consumers.

Two unusual cases of adult intussusception

Adult intussusception is very rare. We report 2 unusual cases, a 58-year-old man with a transverse colo-colonic intussusception caused by a malignant sessile polyp that also had an asymptomatic synchronous neoplasm of the kidney, and an 18-year-old female with an ileocecolic intussusception caused by acute appendicitis. This report stresses the point that intussusception in adults may represent an underlying malignancy. The age of the patient and the anatomic location of the intussusception provide significant input as to the etiology and hence the most appropriate surgical procedure.

Melanoma in African-Americans: trends in biological behavior and clinical characteristics over two decades

BACKGROUND

The incidence of melanoma in the United States is increasing. Data on this disease in African-Americans is sparse.

METHODS

Chart review of patients diagnozed with melanoma from 1975 to 1997 at Charity Hospital New Orleans (CHNO). Age, gender, anatomic distribution, histology, presenting stage, survival, and race were evaluated.

RESULTS

Forty-four of 198 patients were African-American, of whom the majority developed cutaneous melanoma on the acral surface of the foot. African-American males were four times more likely to present with a cutaneous lesion than were African-American females. The median survival time for African-American with cutaneous lesions was 45 months, compared to 135 months for caucasians who were 3.6 times more likely to present with early disease (P < 0.05). TNM stage at presentation, and ulceration were significant, independent factors associated with a worse outcome in African-Americans.

CONCLUSION

Overall survival time for African-Americans with cutaneous melanoma is significantly shorter than for caucasians with this disease. This trend may be attributable to the fact that African-Americans present with advanced disease. An increased level of awareness among both patients and health-care providers is necessary to identify African-Americans with melanoma at earlier stages of disease and to improve survival.

Glutamine is essential for nitric oxide synthesis by murine macrophages

BACKGROUND

Recent studies suggest an interaction between l-arginine (Arg) and l-glutamine (Gln) in the control of nitric oxide (NO) synthesis. Endotoxemia enhances Gln demand and NO production. This study was initiated to investigate the effects of altered Gln availability on the capacity of macrophages to produce NO and the interaction of Gln with l-citrulline (Cit) and Arg in the regulation of endotoxin-stimulated NO synthesis.

METHODS

Cultures of RAW 264.7 macrophages in MEM containing Gln (0 to 100 mM) or Arg (0 or 0.6 mM) and supplemented or not with Cit (0.31 to 10 mM) were exposed to Escherichia coli lipopolysaccharide (LPS) at 0.001 and 1 microg/ml. After 24-h incubation, supernatants were evaluated for nitrite concentrations by Greiss reaction as a measure of NO synthesis.

RESULTS

LPS stimulated nitrite synthesis in a dose-dependent fashion. Macrophages cultured in Gln-free medium containing Arg (0.6 mM) did not produce NO when stimulated with LPS. In contrast, in the presence of Arg and 0.001 microg/ml LPS, adding as little as 0.31 mM Gln resulted in a 23-fold increase in NO production (from 0.13 +/- 0. 02 to 2.92 +/- 0.06 nmol/ml) (P < 0.0001). Furthermore, a dose-dependent increase in LPS-stimulated nitrite release was observed with increasing amounts of Gln to as much as 1 mM. LPS-stimulated macrophages cultured in Arg-free medium containing Gln (0.31-10 mM) did not produce significant amounts of nitrite. However, in the absence of Arg, increasing extracellular Gln levels to 100 mM in the culture medium resulted in nitrite synthesis (2.39 +/- 0.11 nmol/ml). Detectable levels of nitrite (2.84 +/- 0.21 nmol/ml) were also documented when stimulated macrophages were incubated in culture medium lacking Arg but containing Cit (0.31 mM) and Gln (2 mM). Increasing Cit levels (0.63 to 10 mM) significantly augmented nitrite release (P < 0.05). Once again, no detectable levels of nitrite were observed when macrophages were cultured in Gln-free medium, even when Arg and Cit were present.

CONCLUSION

These results suggest that Gln is an essential amino acid for NO synthesis by macrophages and raise the strong possibility that Gln acts with nitric oxide synthase to catalyze the conversion of Arg to NO. The consumption of Gln during sepsis may represent NO production.

What's black and white and red (read) all over? The bedside interpretation of diagnostic peritoneal lavage fluid

Diagnostic peritoneal lavage (DPL) is often used to determine whether a blunt trauma victim has significant intra-abdominal hemorrhage. One bedside test (BT) historically recommended to evaluate DPL fluid is the ability to read newsprint through the fluid contained within intravenous (i.v.) tubing. Few experimental data support this practice. Two hundred eighteen traumatologists were queried regarding their use of BTs. In a related clinical study, blinded volunteers were asked to read print through various unmarked containers filled with simulated DPL fluid, created by adding aliquots of whole human blood to liter bags of lactated Ringer's solution. Of the 97 traumatologists who completed our preliminary survey, 60 per cent reported using a visual BT to assess DPL fluid. Of these surgeons, 44 per cent attempted to read newsprint through i.v. tubing. Our clinical study showed that more volunteers could read print through a red top tube (95%) when it contained a red cell concentration of 827 +/- 41/mm3 than the i.v. bag (4%). Nearly 70 per cent of volunteers were able to read print through the tubing containing 41,429 +/- 2,967 red blood cells (RBCs)/mm3. Regardless of the receptacle, readability was lost at RBC counts far below 100,000/mm3. Many traumatologists utilize BTs as an adjunct to clinical decision making. We conclude that, if the clinician can read print through lavage fluid within an i.v. bag, Vacutainer tube, or i.v. tubing, the DPL will be negative at cell count. However, inability to read print through i.v. tubing requires laboratory confirmation to document an RBC count > 100,000/mm3.