A systematic review and meta-analysis of predictors of recurrence in patients with Solid Pseudopapillary Tumors of the Pancreas.

BACKGROUND: The recurrence rates and predictors of recurrence in patients with Solid Pseudopapillary tumors (SPT) are unclear, which makes it challenging to determine the duration of follow-up. The aim of the current study was to perform a systematic review and meta-analysis to determine the recurrence rates and pathologic factors associated with recurrence in patients with SPT. METHODS: A PubMed, Scopus, and Web of Science search was conducted to identify studies of SPT published during the last 15 years: (09/2002-09/2017). Studies reporting on patients with SPT and follow-up of >5 years were included. The search strategy was conducted per 2009 PRISMA guidelines. RESULTS: A total of 103 studies reporting on 2599 non-metastatic SPT patients were identified. Sixty-nine patients (2.6%) developed recurrence during follow-up. Pooled estimates from studies with a sample size >20 (N = 33) noted an overall recurrence rate of 2% (95% CI 1-2%). Male gender (OR 1.960), positive lymph nodes (OR 11.9), R1 margins (OR 11.1), and LVI (OR 5.5), were associated with a significantly (all p < 0.05) increased risk of recurrence. CONCLUSION: Current meta-analysis suggests that only 2% of patients with SPT experience recurrence after resection. These data will guide the treating physicians and patients regarding recurrence rates and help identify patients at increased risk of recurrence during follow-up.

Nonoperative Management May Be a Viable Approach to Plexiform Neurofibroma of the Porta Hepatis in Patients with Neurofibromatosis-1.

BACKGROUND: Plexiform neurofibroma (PNF) in the porta hepatis (PH) is an unusual manifestation of neurofibromatosis-1 (NF-1). Resection is often recommended given the risk of malignant transformation. We encountered a challenging case in clinical practice which prompted us to report our findings and perform a systematic review on the management of these tumors. METHODS: We reported the case of a 31-year-old woman with NF-1 and PNF of the PH. PRISMA 2009 guidelines were followed for systematic review. RESULTS: Our patient was found to have unresectable disease at exploration. After >5 years of follow-up, she continued to have stable disease on imaging. We identified 12 studies/case reports including 10 adult and 6 pediatric patients with PNF of PH. None of the 7 adult patients with NF-1 and PNF of PH underwent a successful tumor resection. All pediatric patients were managed with surveillance alone. All but one pediatric patient had NF-1. None of the reported cases of PNF of PH had malignant transformation. CONCLUSION: Our findings suggest that PNFs of PH in the setting of NF-1 are often unresectable and may have an indolent course. Surveillance alone may be a reasonable option in some patients; however, further studies are needed.

Long-term survival in a patient with metastatic oropharynx squamous cell carcinoma to liver.

The traditionally held view is that the patients with metastatic disease cannot be cured and should be treated palliatively as it was believed that the patients will eventually succumb to the disease progression due to lack of effective treatments for systemic disease. In this article, we report our experience in a patient who was diagnosed with metastatic oropharynx squamous cell carcinoma to the liver, who has now survived five years since the original diagnosis, and is three years disease free. This case report illustrates the curative potential in selected patients with limited burden of metastatic disease with aggressive local therapy to all known sites of disease. It underscores the importance of imaging modalities in monitoring progression of disease, and most importantly illustrates the importance of multidisciplinary care for oncology patients.

A novel robotic monofilament test for diabetic neuropathy.

OBJECTIVE: The use of the Semmes-Weinstein (SW) monofilament test is recommended as a screening method for diabetic neuropathy. It offers an important chance to prevent further complications of diabetic foot. We aimed to develop a prototype Robotic Monofilament Inspector that can be used as a standard machine for screening of diabetic neuropathy. METHODS: Development was divided into three parts: computer software, control box, and Robotic Monofilament Inspector. The examiner conducted the SW test (by hand and by robotic inspector), vibration perception threshold, and Toronto Clinical Scoring System without knowledge of patient information. The unpaired t test or Wilcoxon rank-sum test was used to determine the differences between independent groups in terms of continuous outcomes, while the χ(2) test was used to determine categorical outcomes. Agreement between the various diabetic neuropathy tests was measured using the kappa statistic. RESULTS: The SW test and vibration perception threshold were more valid tests for neuropathy than the Toronto test. The robotic test was in excellent agreement with the two former tests and appeared to be valid (kappa statistic, 0.35-0.81). Another indirect evidence for the validity of the robotic test was the finding that diabetic patients with foot ulcers had a higher prevalence of neuropathy (77%vs. 38%). This might indicate that the robotic test was more valid than the manual test. CONCLUSION: The Robotic Monofilament Inspector could be used as a simple screening machine. This prototype may be developed further for routine clinical use.

Deep venous thrombosis in surgical intensive care unit: prevalence and risk factors.

BACKGROUND: Critically ill patients are at high risk for developing venous thromboembolism. The objective of this study was to determine the prevalence of, and risk factors for, lower extremity deep vein thrombosis (DVT) among critically ill surgical patients in Thailand. MATERIALS AND METHODS: Patients older than 15 years who were admitted to a surgical intensive care unit (ICU) of a tertiary care hospital were enrolled. Bilateral lower extremity compression Doppler ultrasonographic examination was performed to detect DVT within 14 days of ICU admission. Demographic data, primary disease, operative intervention, co-morbidities, acute physiology and chronic health evaluation (APACHE) II score and the length of ICU stay were tested for association with the presence of DVT. RESULTS: Among the 190 first-time admitted ICU patients with a mean APACHE II score of 9.2 +/- 6.0 (range, 0-29), 20 patients had DVT (prevalence of 10.5%). Thromboprophylaxis was not given to any patient. The only independent and significant risk factor for DVT was a longer ICU stay. Age, sex, APACHE II score, presence of comorbidities and operative intervention were not associated with the presence of DVT. CONCLUSION: The prevalence of DVT in critically ill patients in a Thai surgical ICU was approximately 10.5%. Further research is needed to evaluate the risks and benefits of venous thromboprophylaxis in Thai patients.

Green tea extract prolongs allograft survival as an adjunctive therapy along with low dose cyclosporine A.

The current immunosuppressive drugs are successful in prolonging allograft survival but fail to achieve transplantation tolerance or prevent chronic rejection. Consequently, there is ongoing research to develop novel combinatorial therapies that are more efficacious in prolonging allograft survival as well as induce tolerance toward the transplanted organ. The present study aims to study the efficacy of green tea extract (GTE) in combination with low dose cyclosporine A (CyA) in prolonging allograft survival in mice. Numerous studies have reported the anti-inflammatory and immunomodulatory properties of GTE and its various catechin components. GTE is also known to attenuate CyA induced nephrotoxicity. Therefore, we hypothesized that GTE alone or in combination with CyA will prolong graft survival. Our study demonstrates that GTE in combination with low dose CyA significantly prolongs graft survival as well as increase the production of immunosuppressive cytokine, IL-10. GTE also decreases CyA induced high TGF-beta production, which is incriminated in CyA induced nephrotoxicity. We also observed that GTE inhibits both nonspecific and antigen-specific proliferation of T cells in vitro. These results indicate the potential of GTE as an adjunctive therapy in combination with CyA to prolong allograft survival and to reduce CyA induced nephrotoxicity.

Cyclosporine inhibition of angiogenesis involves the transcription factor HESR1.

PURPOSE: Angiogenesis is critical in normal development and in tumor growth. Experimentally, cyclosporine A (CyA) inhibits angiogenesis in an in vivo mouse model and an in vitro capillary tube model. The mechanisms behind its antiangiogenic effects are not well characterized. To determine which nuclear factor, if any, may be involved in the antiangiogenic effects of CyA, we performed a microarray analysis of human aortic endothelial cells (HAEC) subjected to CyA and another calcineurin inhibitor, FK 506. METHODS: HAEC were divided into four groups: (1) HAEC incubated with CyA 2 microg/mL; (2) HAEC incubated with CyA 10 microg/mL; (3) HAEC incubated with FK 506 1 microg/mLl for 24 h; and (4) HAEC as control. We used Affymetrix GeneChip U133-A for gene expression analysis and validated our results with quantitative reverse transcription-polymerase chain reaction. RESULTS: At a 2 microg/mL dose, CyA treated HAEC revealed a 44-fold increase in the expression of hairy enhancer of split-related protein 1 (HESR1) and 1.73-fold down-regulation of transcripts encoding for the vascular endothelial growth factor (VEGF) receptor (VEGFR2). At 10 microg/mL, the expression of the HESR1 transcript was 57-fold higher than control, and VEGFR2 exhibited a 1.93-fold down-regulation. Quantitative reverse transcription-polymerase chain reaction confirmed a significant (P < 0.0001) increase in expression of HESR1 in CyA treated cells. In contrast, the expression level of HESR1 was not affected by the FK 506 treatment. CONCLUSION: CyA demonstrate antiangiogenic activities linked to an overexpression of HESR1 transcription factor, and down-regulation of VEGFR2. Thus, use of high-dose CyA may provide a novel treatment in angiogenesis dependent disease.

An interleukin-6-neutralizing antibody prevents cyclosporine-induced nephrotoxicity in mice.

INTRODUCTION: Chronic use of cyclosporine A (CyA) induces nephrotoxicity primarily due to endothelial dysfunction. In our previous studies, potential mechanisms were identified in vitro and implicated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and interleukin-6 (IL-6) as key components in causing endothelial dysfunction. In this study, we tested the hypothesis that NADPH oxidase activity and IL-6 are key components in renal damage in an in vivo model. METHODS: Male mice C57B/6 mice from Jackson Laboratory (Bar Harbor, ME) at 6-8 wks were subjected to a low-salt diet throughout the trial. After 1 week on a low-salt diet, the mice were injected daily with treatments in 50 muL vehicle composed of 75% cremaphor (Sigma, St. Louis, MO) and ethanol for 5 wks. A vehicle-alone group was also set aside. Mice were weighed and 25 mg/kg/day cyclosporine (Novartis Pharma, St. Louis, MO) was injected daily. Apocynin (Calbiochem, Gibbstown, NJ) 20 mg/kg were injected either alone or concomitantly with CyA. Another group of mice were administered IL-6 antibody (Cat no. MAB406; R&D Systems, Minneapolis, MN) at 2 mug/day along with CyA. The kidneys were removed en bloc immediately and submitted in formalin for paraffin sections. Trichrome stains were performed. Slides were blinded and 10 photographs of cortical areas per treatment group were taken, which covered an estimate of 10% surface area in random fashion. Areas of renal damage, which were determined by tubular necrosis, were identified and quantified by amount of necrosis per photograph. Each photograph was divided into 10 blocks, and the number of blocks that contained necrotic tubules per photo was recorded. RESULTS: The two control mice (low salt only) had no damage. The four vehicle mice had trace amounts of tubular necrosis. CyA treatment group demonstrated the highest amount of damage (29/70; 41%). CyA with apocynin, a specific NADPH oxidase inhibitor, was found to have 36% (22/60) damage, whereas the CyA with IL-6 antibody only was observed to have 15% (6/40) damage. Comparing imaging analysis, there was no difference between mice treated with CyA alone and with CyA with apocynin. However, the amount of damage in mice treated with CyA and IL-6 antibody was found to be significantly lower than both CyA and CyA with apocynin. CONCLUSIONS: CyA action as a calcineurin inhibitor has allowed prolongation of kidney transplants, but its chronic use has led to devastating consequences such as allograft nephropathy. Previously, we have identified potential mechanisms of CyA-induced endothelial dysfunction in vitro. The current study identifies increased IL-6 expression as a mechanism by which CyA induces renal damage and that the use of an IL-6-neutralizing antibody may be useful in reducing CyA-induced renal damage.

Ginger extract inhibits LPS induced macrophage activation and function.

BACKGROUND: Macrophages play a dual role in host defence. They act as the first line of defence by mounting an inflammatory response to antigen exposure and also act as antigen presenting cells and initiate the adaptive immune response. They are also the primary infiltrating cells at the site of inflammation. Inhibition of macrophage activation is one of the possible approaches towards modulating inflammation. Both conventional and alternative approaches are being studied in this regard. Ginger, an herbal product with broad anti inflammatory actions, is used as an alternative medicine in a number of inflammatory conditions like rheumatic disorders. In the present study we examined the effect of ginger extract on macrophage activation in the presence of LPS stimulation. METHODS: Murine peritoneal macrophages were stimulated by LPS in presence or absence of ginger extract and production of proinflammatory cytokines and chemokines were observed. We also studied the effect of ginger extract on the LPS induced expression of MHC II, B7.1, B7.2 and CD40 molecules. We also studied the antigen presenting function of ginger extract treated macrophages by primary mixed lymphocyte reaction. RESULTS: We observed that ginger extract inhibited IL-12, TNF-alpha, IL-1beta (pro inflammatory cytokines) and RANTES, MCP-1 (pro inflammatory chemokines) production in LPS stimulated macrophages. Ginger extract also down regulated the expression of B7.1, B7.2 and MHC class II molecules. In addition ginger extract negatively affected the antigen presenting function of macrophages and we observed a significant reduction in T cell proliferation in response to allostimulation, when ginger extract treated macrophages were used as APCs. A significant decrease in IFN-gamma and IL-2 production by T cells in response to allostimulation was also observed. CONCLUSION: In conclusion ginger extract inhibits macrophage activation and APC function and indirectly inhibits T cell activation.

Three-dimensional aortic aneurysm model and endovascular repair: an educational tool for surgical trainees.

OBJECTIVES: Endovascular aortic aneurysm repair (EVAR) is a current valid treatment option for patients with abdominal aortic aneurysms (AAAs). The success of EVAR depends on the selection of appropriate patients, which requires detailed knowledge of the patient's vascular anatomy and preoperative planning. Three-dimensional (3D) models of AAA using a rapid prototyping technique were developed to help surgical trainees learn how to plan for EVAR more effectively. METHOD: Four cases of AAA were used as prototypes for the models. Nine questions associated with preoperative planning for EVAR were developed by a group of experts in the field of endovascular surgery. Forty-three postgraduate trainees in general surgery participated in the present study. The participants were randomly assigned into two groups. The 'intervention' group was provided with the rapid prototyping AAA models along with 3D computed tomography (CT) corresponding to the cases of the test, while the control group was provided with 3D CTs only. RESULTS: Differences in the scores between the groups were tested using the unpaired t test. The mean test scores were consistently and significantly higher in the 3D CT group with models compared with the 3D CT group without models for all four cases. Age, year of training, sex and previous EVAR experience had no effect on the scores. CONCLUSION: The 3D aortic aneurysm model constructed using the rapid prototype technique may significantly improve the ability of trainees to properly plan for EVAR.

Comparison of risk-scoring systems in predicting hospital mortality after abdominal aortic aneurysm repair.

OBJECTIVE: To compare the Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity, Portsmouth adjustment (P-POSSUM), the Hardman index and the Glasgow aneurysm score (GAS) in the prediction of hospital mortality after abdominal aortic aneurysm (AAA) repair. METHODS: Medical charts of 146 AAA patients treated between January 1996 and January 2007 were reviewed. The P-POSSUM, Hardman index and GAS were calculated for each patient. The scores were tested and compared for their discriminatory ability to predict hospital death. RESULTS: Of the 146 patients with ruptured and unruptured AAAs (133 underwent open repair, five underwent extra-anatomical bypass and eight underwent endovascular aneurysm repair), 18 died (12%) after AAA repair. The areas under the receiver operating characteristic curves for the GAS, Hardman index and P-POSSUM for predicting hospital mortality were 0.740, 0.730 and 0.886, respectively. The area under the receiver operating characteristic curve for the P-POSSUM was significantly higher than those of other scores. CONCLUSION: In the present study, the P-POSSUM was the best predictor of hospital mortality for patients undergoing AAA repair.

Effect of 6-gingerol on pro-inflammatory cytokine production and costimulatory molecule expression in murine peritoneal macrophages.

BACKGROUND: Pro-inflammatory cytokines produced primarily by macrophages are key elements in many surgical conditions including sepsis, ischemia-reperfusion injury, and transplant rejection. Herbal products are being used as alternative treatments in such inflammatory conditions. Ginger is known for its ethno-botanical applications as an anti-inflammatory agent. 6-gingerol is one of the active ingredients of ginger that imparts ginger with its anti-inflammatory properties. We hypothesized that the anti-inflammatory effect of 6-gingerol is because of inhibition of macrophage activation, more specifically by an inhibition of pro-inflammatory cytokines and antigen presentation by lipopolysaccharide (LPS) activated macrophages. METHODS: To study the effect of 6-gingerol on pro-inflammatory cytokines, we measured the liberation of TNF-alpha, IL-1beta, and IL-12 by murine peritoneal macrophages exposed to several doses of 6-gingerol in the presence of LPS stimulation. We also studied the effect of 6-gingerol on the cell surface expression of B7.1, B7.2, and MHC II. Finally, we examined the APC function of the 6-gingerol treated macrophages by a primary mixed lymphocyte reaction. RESULTS: 6-gingerol inhibited the production of pro-inflammatory cytokines from LPS stimulated macrophages but had no effect on the LPS-induced expression of B7.1, B7.2, and MHC II. The APC function of LPS stimulated macrophages was also unaffected by 6-gingerol treatment. CONCLUSION: Our data indicate that 6-gingerol selectively inhibits production of pro-inflammatory cytokines from macrophages but does not affect either the APC function or cell surface expression of MHC II and costimulatory molecules. We, thus, provide a mechanistic insight into the anti-inflammatory properties of 6-gingerol that may be useful to treat inflammation without interfering with the antigen presenting function of macrophages.

A novel extracorporeal kidney perfusion system: a concept model.

The number of patients awaiting kidney transplantation has more than doubled in the past decade while the number of available donor organs has seen only a modest increase, leading to a critical shortage of organs. In response to this extreme shortage, the criteria for accepting organs have been modified to include marginal donors such as non-heart beating donors (NHBD). In these kidneys, determining viability is important for success of transplantation. Therefore, a study was undertaken to develop a system that would allow the extracorporeal assessment of function and compatibility of the donor organ before the patient is exposed to the risks associated with surgery. Following bilateral nephrectomy, the kidneys of 10 pigs (approximately 30 kg) were connected to a commercially available hypothermic pulsatile kidney perfusion apparatus. This system was modified to allow for normothermic pulsatile renal perfusion using the potential recipient's blood, via vascular access. These kidneys were perfused with the animal's blood for a minimum of two hours while various parameters were monitored. Perfusion pressures were kept between 60 and 90 mmHg, which correlated to flows between 70 and 150 mL/min. A decrease in perfusion pressure with a concomitant rise in flow over the two-hour period served as a good predictor of a viable and compatible graft. The modified kidney preservation system allows the normothermic, pulsatile extracorporeal perfusion of donor kidneys with the ability to monitor resistance to flow and urine production. This model also allows observation of the kidney for signs of hyperacute rejection. Further research needs to be conducted in order to determine if the system represents a methodology to increase the pool of available donor organs.

Resident perceptions of the impact of work-hour restrictions on health care delivery and surgical education: time for transformational change.

BACKGROUND: The Accreditation Council for Graduate Medical Education has recently enacted an 80-hour workweek, which has been in effect in New York State for several years. We surveyed surgical residents from all four State University of New York (SUNY) surgical programs to determine their perceptions of the impact of the 80-hour workweek on patient care, surgical education, and personal life. METHODS: A survey instrument to address the three areas of concern was developed and administered to all surgical residents at the four SUNY programs. Anonymity of the responders was maintained. Responses to the questions were in numeric rank scores and were analyzed by descriptive statistics, chi-square analysis, and analysis of variance. RESULTS: Response rate was 59%. Factors perceived to be affected negatively by the residents were continuity and safety of care, their operative experience, and their relations with attendings. The factors affected positively were increased personal time and decreased fatigue at work. Interestingly, the latter did not appear to decrease the rate of medical errors in their perception. CONCLUSIONS: The 80-hour workweek has the potential to have adverse effects on patient care despite improving the level of fatigue at work. Reengineering the surgical residencies will be needed to take full advantage of the restricted work hours.

Ultrastructural changes in cirrhotic and noncirrhotic patients due to hepatectomy.

BACKGROUND/PURPOSE: Alterations at the ultrastructural level can be identified prior to histological change in the early phase of irreversible cell damage. The aim of this investigation was to compare the ultrastructural changes in cirrhotic and noncirrhotic liver in response to ischemic and reperfusion injury due to hepatectomy. METHODS: Hepatic resections using the same technique were performed in cirrhotic and noncirrhotic patients. Three biopsy specimens (Tru cut) from each patient, in the unresected part of the liver, were studied by transmission electron microscopy: immediately after laparotomy, before releasing of the porta hepatis clamp (ischemic phase), and 30-45 min after reperfusion. RESULTS: All patients did well after surgery, except for 1 cirrhotic patient who died of liver failure. There were no significant differences in operative time, blood loss, and inflow occlusion times in any of the 15 patients. We found that morphological changes were the same in the 10 non-cirrhotic and 4 cirrhotic patients. Changes during the ischemic phase included nuclear membrane deformity, focal chromatin condensation at the nuclear margin, and swelling of both mitochondria and endoplasmic reticulum. In the reperfusion phase, there were early irreversible changes in the nuclei of some hepatocytes and intramitochondrial particles and increased vacuolization in cytoplasm. Endothelial cells, Kupffer cells, bile canaliculi, and Ito cells were not affected in either the ischemic or the reperfusion phase. However, in the 1 cirrhotic patient who died of liver failure, there were marked swelling and dilated cristae in mitochondria during the ischemic phase and deformity of Ito cells during the reperfusion phase. CONCLUSIONS: In this, the first report of ultrastructural changes due to hepatectomy in cirrhotic patients, we found that the changes were the same as those in non-cirrhotic patients, except for the one cirrhotic patient who had postoperative liver failure.

The effect of allo-injury in an in vitro model of allograft microvasculature.

Endothelial cells are critical to the integrity of allograft vasculature and can be damaged by alloreactive T cells or soluble mediators of alloreactivity. The biochemical effects of T cell-mediated damage to the endothelial cells have been studied, but not the structural and morphological effects of allo-injury on endothelial cells in the allograft. We utilized an assay that reproduces microvasculature in vitro to study the effect of alloreactivity on endothelial cells. In this assay, endothelial cells are induced into capillary-like networks that simulate microvascular capillaries. We studied the effect of allogeneic T cells and of soluble mediators from both mixed lymphocyte cultures (MLCs) and rejected heart allograft tissue on the in vitro capillaries. We found that both allogeneic T cells and soluble mediators inhibit the formation of the in vitro endothelial capillaries, suggesting that they cause a mild-to-moderate dysfunction of the endothelial cells. The inhibitory effect of the soluble mediators seems to be mediated, at least partly, by IFN-gamma, since this effect was prevented by antibody to IFN-gamma. Furthermore, pre-incubation of the in vitro capillaries with IFN-gamma appeared to magnify the effect of allogeneic T cells, as shown by a complete breakdown of well-formed in vitro capillary networks. Our experiments suggest that the in vitro capillary-tube model reflects structural injury to allograft vasculature by alloreactive T cells and their soluble mediators.

Soluble interleukin 2 receptor (sIL-2R) levels in renal transplant recipients.

BACKGROUND: Allograft rejection is associated with T cell activation. T cell activation leads to secretion of soluble IL-2 receptor and elevated serum soluble IL-2 receptor (sIL-2R) levels. However, the clinical implication of individual elevated sIL-2 receptor levels is unclear. We followed levels of sIL-2R pre- and post-transplantation to determine if sIL-2R levels predict rejection episodes or degree of graft function. MATERIALS AND METHODS: Serum samples of 12 patients who underwent living or cadaveric renal transplant were followed weekly with serial sIL-2R levels. These levels were followed until the serum creatinine reached a baseline. Of the 12 patients, three patients developed delayed graft function. The remaining nine patients were followed for a period of 3 months. Sera of these nine patients in the initial 3 months post-transplant were monitored for sIL-2R levels. For comparison, sIL-2R levels were also measured in 150 healthy volunteers and five dialysis patients. RESULTS: Recipients undergoing severe rejection episodes had higher overall serum levels of sIL-2R (1515 +/- 496 U/mL) as compared with recipients who had stable renal transplants and no episodes of rejection (698 +/- 333 U/mL) (P = 0.034). Comparison of sIL-2R ratios (post-transplant sIL-2R level/pre-transplant sIL-2R level) revealed that ratios of 0.6 or higher were more frequently seen in patients who subsequently underwent severe rejection episodes. Dialysis patients were found to have higher sIL-2R levels (2605 +/- 1312 U/mL) compared with renal transplant patients (1047 +/- 192 U/mL) (P < 0.001) and healthy volunteers (349 +/- 185 U/mL) (P < 0.001). CONCLUSION: Our results suggest that individual levels of sIL-2R are not predictive of rejection in the early post-transplant period, but s-IL2R ratios greater than 0.6 may be predictive of severe rejection episodes.

Cross-species comparison of gene expression between human and porcine tissue, using single microarray platform--preliminary results.

INTRODUCTION: Xenotransplantation is a potential solution for inadequate supply of donor organs. Pigs are considered the ideal donor for kidney transplantation to human recipients, therefore it is important to understand the gene regulation in the porcine organs. Oligonucleotide array technology has been utilized largely for human, mouse and rat gene expression studies only. Its use with porcine genes has not been reported. We investigated the possibility of studying gene regulation in porcine kidney with a human GeneChip microarray platform. METHODS: To assess the feasibility of using a single microarrray platform for comparison of expressing data across different species (human and pig), we compared the gene expression profiles of human brain, human kidney and pig kidney using the Affymetrix U-133 A human GeneChip, which contains probes for 22,283 genes. Kidney biopsies from pigs and humans, with normal histology, were used to obtain RNA for porcine and human samples, while a commercially available adult whole cortex total RNA sample (Clontech) was used for the human sample. We assessed the intensity ratio for housekeeping and tissue specific genes. To examine the potential for non-specific binding to create false positive errors in our data, we compared the expression profiles in our experiments to a number of public databases. RESULTS: There were approximately the same number of genes expressed at higher levels in the pig kidney as in the human kidney and human brain. The major differences in gene expression were found for genes with tissue specific patterns of expression. Eighty genes were increased in human brain vs. human and pig kidney samples. Two hundred and eighty genes were increased in human and pig kidney vs. human brain samples. Of the top 25 genes increased in pig kidney compared with human brain, we were able to cross-reference 18 genes to the Unigene and SAGE public databases. We confirmed the expected higher levels of expression in the kidney in 18 genes. Of the top 25 genes increased in human brain vs. pig kidney, we were able to cross-reference 20 genes to the Unigene and SAGE databases and confirm the expected higher expression levels in brain in 17 genes with three inconclusive genes. CONCLUSION: This low level of false positive findings, at this preliminary stage, supports the concept of using human GeneChip microarray platform to compare gene expression profiles between pig and human tissues in the absence of a porcine microarray platform. Our study opens a new avenue into the analysis of porcine genes relevant to xenotransplantation.

Signal transduction pathway in endothelial dysfunction.

BACKGROUND: Endothelial dysfunction is an important feature of sepsis, acute respiratory distress syndrome (ARDS), and other infectious conditions. Previously, we reported an in vitro model to study endothelial dysfunction, in which endothelial cells are induced to form capillary tube networks by culturing on a basement membrane matrix (Matrigel). In this study, we defined the signal transduction pathways that lead to endothelial cell function and capillary disruption characteristic of sepsis and other infectious conditions. METHODS: Human aortic endothelial cells (HAEC) were cultured on a laminin-rich matrix to form capillary-like networks. The HAECs were treated with a protein tyrosine phosphatase inhibitor (sodium orthovanadate), a phosphoinositon-3-phosphate inhibitor (wortmannin), or a protein kinase C inhibitor (bisindolylmaleimide) before capillary tubes had formed or after the capillary tubes had matured. The degree of capillary tube formation was quantified by counting the intersection of capillary networks in triplicate wells. Statistical significance was determined by analysis of variance. RESULTS: Endothelial dysfunction occurred after inhibition of protein tyrosine phosphatase or protein kinase C. Whereas inhibition of phosphoinositon-3-phosphate did not cause endothelial dysfunction, sodium orthovanadate (2-20 microM) and bisindolylmaleimide (2-10 microM) significantly reduced capillary networks. The mean +/- SD of the number of capillary tubes in the control, sodium orthovanadate-treated, and bisindolylmaleimide-treated groups were 251.0 +/- 7.0, 65.6 +/- 9.9 (p < 0.001), and 181.7 +/- 0.1 (p < 0.001), respectively. Sodium orthovanadate (20-200 microM) and bisindolylmaleimide (10-100 microM) inhibited capillary tube formation. At higher concentrations, sodium orthovanadate (> 200 microM) and bisindolylmaleimide (>100 microM) disrupted mature capillary tubes. CONCLUSIONS: Our results suggest that PKC and protein tyrosine phosphatase play a role in endothelial dysfunction by interfering with the phosphorylation signals within endothelial cells. These mechanisms may be important in the endothelial dysfunction in sepsis and other infectious conditions.

Augmentation of ischemia/reperfusion injury to endothelial cells by cyclosporin A.

Ischemia/reperfusion (I/R) carries significant injury to endothelial cells in transplanted organs and is an important factor in chronic rejection. Immunosuppressive drugs, notably cyclosporin A (CyA) and FK506, can potentially augment this injury. Here, our goal was to determine the combined effects of I/R and CyA or FK506 on endothelial cells. Transformed mouse endothelial cells (SVEC 4-10) were subjected to ischemia or I/R for 2-24 hours by incubating cells in 100 per cent N2 (ischemia) followed by 5 per cent CO2 and 95 per cent O2 (reperfusion) for 24 hours. In separate experiments, CyA or FK506 was added to cells subjected to ischemia or I/R. Nonviable cells were determined by Trypan blue exclusion assay. All experiments (done in triplicate) were analyzed by Student's t test. Increasing ischemia times resulted in a greater number of nonviable cells (2% nonviable cells at 0 hours and 57% at 24 hours of I/R). Addition of CyA significantly increased the number of nonviable cells when compared with the control (I/R only) group (P = 0.014). Interestingly, FK506 did not increase the percentage of nonviable cells compared with the control group (P = 0.2). Unlike FK506, CyA augments I/R injury to endothelial cells in vitro. These findings could be relevant in chronic rejection and transplantation.