Ruptured abdominal aortic aneurysm-epidemiology, predisposing factors, and biology.

PURPOSE: Abdominal aortic aneurysm is a common degenerative vascular disorder associated with sudden death due to aortic rupture. This review describes epidemiology, predisposing factors, and biology of ruptured abdominal aortic aneurysms (rAAAs). METHODS: Based on a selective literature search in Medline (PubMed), original publications, meta-analyses, systematic reviews, and Cochrane reviews were evaluated for rAAA. RESULTS: The hospital admission rate for rAAA is decreasing and is now in the range of approximately 10 per 100,000 population in men. Smoking contributes to about 50 % of population risk for rupture or surgically treated AAA. AAA rupture is a multifaceted biological process involving biochemical, cellular, and proteolytic influences, in addition to biomechanical factors. AAA rupture occurs when the stress (force per unit area) on the aneurysm wall exceeds wall strength. Proteolytic activities of matrix metalloproteinases have been implicated in aneurysm wall weakening and rupture. Aneurysm diameter is the most prominent predisposing factor for aneurysm growth and rupture. Wall stress, aneurysm shape and geometry, intraluminal thrombus, wall thickness, calcification, and metabolic activity influence the rupture risk. CONCLUSION: The best conservative option to avoid AAA rupture consists in smoking cessation and control of hypertension. Many biological factors influence rupture risk.

Hybrid approach to emergent and urgent treatment of complex thoracoabdominal aortic pathology.

OBJECTIVES: The aim was to report a single center experience with hybrid procedures in the emergency treatment of patients with thoracoabdominal aortic pathology. Thoracoabdominal aortic aneurysm (TAAA) repair is primarily conducted by conventional surgery in the urgent and emergency setting. The role of hybrid procedures with stent graft coverage of the aorta and extra-anatomical debranching of the renovisceral arteries has so far not been defined in this context. METHODS: From 2007 to 2013 30 patients (21 males, 9 females) undergoing an emergent or urgent TAAA hybrid procedure were included in a data register. The mean aneurysm diameter was 72 mm. Etiology was atherosclerosis in 23 patients (76.7%) and aortic dissection in seven patients (23.3%). Nineteen patients (63.3%) required emergency surgery. In 11 cases (36.7%), surgery was indicated for symptomatic aneurysms. Mean follow-up was 16 months (range 1-72 months). RESULTS: The hybrid procedure was completed in all patients. Renovisceral revascularization was performed with a total of 101 grafts (25 to the celiac, 30 to the superior mesenteric, 25 to the right renal, and 21 to the left renal artery). The 30-day and 1-year primary graft patency was 97.3% and 95.3% respectively. A median of three stent grafts per patient was deployed. One patient underwent surgical intervention for early endoleak (3.3%). Three patients (10%) developed spinal ischemia with persistent paraplegia. Two patients (6.7%) required chronic hemodialysis. Thirty-day mortality reached 26.7% (N = 8), being 36.8% in emergency patients (7 of 19) and 9.1% in the urgent group (1 of 11 patients). The cumulative postoperative survival rate after 12 months was 57.8%. CONCLUSIONS: Hybrid procedures have the potential to be an alternative treatment option for complex thoracoabdominal pathology in the urgent and emergency setting. The procedure is readily available and enables adequate surgical repair with enduring results. Nevertheless it is still associated with significant mortality and morbidity.

[Complications of venous port systems : Radiological diagnostics and minimally invasive therapy]. / Komplikationen venöser Portsysteme : Radiologische Diagnostik und minimalinvasive Therapie.

INTRODUCTION: Documentation of a correct port placement is a routine investigation in radiology. This article describes typical complications of port catheters and minimally invasive treatment options which can guarantee further use without complications. MATERIAL AND METHODS: From January 2009 to May 2010 a surgical port placement was carried out on 174 patients at the University Clinic in Mannheim and of these, 52 patients were admitted to our institute for radiological imaging of the port. Minimally invasive treatment options are presented based on the observed port complications. RESULTS: Of the 52 patients 7 (13.5%) received a port catheter lysis. A successful port position correction was carried out in 3 (5.8%) patients with a malpositioned port catheter and port removal was recommended in 2 patients (3.8%) due to extensive arm venous thrombosis. A minimally invasive port catheter treatment allowed further use of the port system without operative revision in the corresponding patients. The measures were tolerated very well by the patients without postinterventional complications.

Fluorescence lifetime imaging microscopy of chemotherapy-induced apoptosis resistance in a syngenic mouse tumor model.

During cancer therapy with DNA-damaging drug-agents, the development of secondary resistance to apoptosis can be observed. In the search for novel therapeutic approaches that can be used in these cases, we monitored chemotherapy-induced apoptosis resistance in a syngenic mouse tumor model. For this, syngenic murine colorectal carcinoma cells, which stably expressed a FRET-based caspase-3 activity sensor, were introduced into animals to induce peritoneal carcinomatosis or disseminated hepatic metastases. This syngenic system allowed in vitro, in vivo and ex vivo analysis of chemotherapy induced apoptosis induction by optically monitoring the caspase-3 sensor state in the tumor cells. Tumor tissue analysis of 5-FU treated mice showed the selection of 5-FU-induced apoptosis resistant tumor cells. These and chemo-naive fluorescent tumor cells could be re-isolated from treated and untreated mice and propagated in cell culture. Re-exposure to 5-FU and second line treatment modalities in this ex-vivo setting showed that 5-FU induced apoptosis resistance could be alleviated by imatinib mesylate (Gleevec). We thus show that syngenic mouse systems that stably express a FRET-based caspase-3 sensor can be employed to analyse the therapeutic efficiency of apoptosis inducing chemotherapy.

'Fast-track' colonic surgery in Austria and Germany--results from the survey on patterns in current perioperative practice.

OBJECTIVE: 'Fast-track' rehabilitation has been shown to accelerate recovery, reduce general morbidity and decrease hospital stay after elective colonic surgery. Despite this evidence, there is no information on the acceptance and utilization of these concepts among the entirety of Austrian and German surgeons. METHOD: In 2006, a questionnaire concerning perioperative routines in elective, open colonic resection was sent to the chief surgeons of 1270 German and 120 Austrian surgical centres. RESULTS: The response rate was 63% in Austria (76 centres) and 30% in Germany (385 centres). Mechanical bowel preparation is used by the majority (Austria, 91%; Germany, 94%); the vertical incision is the standard method of approach to the abdomen in Austria (79%) and Germany (83%), nasogastric decompression tubes are rarely used, one-third of the questioned surgeons in both countries use intra-abdominal drains. Half of the surgical centres allow the intake of clear fluids on the day of surgery and one-fifth offer solid food on that day. Epidural analgesia is used in three-fourths of the institutions. CONCLUSION: Although there is an evident benefit of fast-track management, the survey shows that they are not yet widely used as a routine in Austria and Germany.

Acute GI bleeding by multiple jejunal gastrointestinal autonomic nerve tumour associated with neurofibromatosis type I.

We describe a surgical emergency due to GI-bleeding caused by gastrointestinal autonomic nerve tumours (GANT s) in a patient with von Recklinghausen s disease. A 72 year old female patient with von Recklinghausen s disease was admitted with maelena. Endoscopy showed no active bleeding in the stomach and the colon. Therefore an angio-CT-scan was performed which revealed masses of the proximal jejunum as source of bleeding. Laparotomy was indicated and a 20 cm segment of jejunum which carried multiple extraluminal tumours was resected. The source of the bleeding was a 2 cm tumour which had eroded the mucosal surface. Immunohistologically, evidence of neuronal differentiation could be shown in the spindle-formed cells with positive staining for C-Kit (CD 117), CD 34, and a locally positive staining for synaptophysine and S100. This case report illustrates the association between neurofibromatosis and stromal tumours and should alert surgeons and gastroenterologist about gastrointestinal manifestations in patients with von Recklinghausen s disease.

Peritoneal cancer treatment with CYP2B1 transfected, microencapsulated cells and ifosfamide.

The prognosis of peritoneal spread from gastrointestinal cancer and subsequent malignant ascites is poor, and current medical treatments available are mostly ineffective. Targeted chemotherapy with intraperitoneal prodrug activation may be a beneficial new approach. L293 cells were genetically modified to express the cytochrome P450 enzyme 2B1 under the control of a cytomegalovirus immediate early promoter. This CYP2B1 enzyme converts ifosfamide to its active cytotoxic compounds. The cells are encapsulated in a cellulose sulfate formulation (Capcell). Adult Balb/c mice were inoculated intraperitoneally with 1 x 10(6) colon 26 cancer cells, previously transfected with GFP to emit a stable green fluorescence, by injection into the left lower abdominal quadrant. Two or five day's later animals were randomly subjected to either i.p. treatment with ifosfamide alone or ifosfamide combined with microencapsulated CYP2B1-expressing cells. Peritoneal tumor volume and tumor viability were assessed 10 days after tumor inoculation by means of fluorescence microscopy, spectroscopy and histology. Early i.p. treatment with ifosfamide and CYP2B1 cells resulted in a complete response. Treatment starting on day 5 and single-drug treatment with ifosfamide resulted in a partial response. These results suggest that targeted i.p. chemotherapy using a combination of a prodrug and its converting enzyme may be a successful treatment strategy for peritoneal spread from colorectal cancer.

Case report-delayed splenic rupture in combination with medial femoral neck fracture after low energy trauma. Development of hemorrhagic shock 5 days after hip prosthesis due to a rare cause.

A 79 year old female patient was admitted to our emergency department with a fracture of the right medial femoral neck six days after a fall on her right side and a cemented hemiprosthesis was implanted. Five days later, she developed a hemorrhagic shock and was diagnosed with a delayed splenic rupture and the spleen was resected. Histopathological examination showed a delayed rupture of an otherwise normal spleen without signs of an underlying pathology. The outcome was fatal: In the postoperative course she developed pneumonia, three weeks later she succumbed due to multiple organ failure. Even careful reevaluation of the case did not provide any clues to expect an injury of the spleen according to trauma mechanism. This case shows that delayed splenic rupture of a normal spleen may occur even after a low energy trauma. Injury of the spleen should therefore always be considered, even with an uncharacteristic anamnesis. Physical examination after trauma should therefore always include a careful clinical evaluation. The clinical threshold for a FAST examination should be low. The coincidence of a femoral neck fracture and a splenic rupture after a low energy trauma has not been reported before.

Targeting mitosis-regulating genes in cisplatin-sensitive and -resistant melanoma cells: A live-cell RNAi screen displays differential nucleus-derived phenotypes.

Chemoresistance in malignant melanoma remains an unresolved clinical issue. In the search for novel molecular targets, a live-cell high-content RNAi screen based on gene expression data was performed in cisplatin-sensitive and cisplatin-resistant MeWo melanoma cells, Mel-28 cells and a melanocyte cell line. Cells were exposed to 91 siRNAs and distinct nucleus-derived phenotypes such as cell division, cell death and migration phenotypes were detected by time-lapse microscopy over 60 h. Using this approach, cisplatin-sensitive and cisplatin-resistant melanoma cells were compared by automated image analysis and visual inspection. In cisplatin-sensitive MeWo melanoma cells, 14 genes were identified that showed distinct phenotype abnormalities after exposure to gene-specific siRNAs. In cisplatin-resistant MeWo cells, five genes were detected. Nine genes were detected whose knock-down led to differential nuclear phenotypes in cisplatin-sensitive and -resistant cells. In Mel-28 cells, nine genes were identified which induced nuclear phenotypes including all eight genes which were identified in cisplatin-resistant MeWo cells. An analogous RNAi screen on melanocytes revealed no detectable phenotype abnormalities after RNAi. Pathway analysis showed in cisplatin-sensitive MeWo cells and Mel-28 cells an enrichment of at least three genes in major mitotic pathways. We hereby show that siRNA screening may help to identify tumor-specific genes leading to phenotype abnormalities. These genes may serve as potential therapeutic targets in the treatment of melanoma.

Platelets from flowing blood attach to the inflammatory chemokine CXCL16 expressed in the endothelium of the human vessel wall.

Endothelial chemokine CXC motif ligand 16 (CXCL16) expression is associated with atherosclerosis, while platelets, particularly those attaching to atherosclerotic plaque, contribute to all stages of atherosclerotic disease. This investigation was designed to examine the role of CXCL16 in capturing platelets from flowing blood. CXCL16 was expressed in human atherosclerotic plaques, and lesion severity in human carotid endarterectomy specimens was positively correlated with CXCL16 levels. CXCL16 expression in plaques was co-localised with platelets deposited to the endothelium. Immobilised CXCL16 promoted CXCR6-dependent platelet adhesion to the human vessel wall, endothelial cells and von Willebrand factor during physiologic flow. At low shear, immobilised CXCL16 captured platelets from flowing blood. It also induced irreversible platelet aggregation and a rise in intra-platelet calcium levels. These results demonstrate that endothelial CXCL16's action on platelets is not only limited to platelet activation, but that immobilised CXCL16 also acts as a potent novel platelet adhesion ligand, inducing platelet adhesion to the human vessel wall.

Microinjected glutathione reductase crystals as indicators of the redox status in living cells.

The flavoenzyme glutathione reductase catalyses electron transfer reactions between two major intracellular redox buffers, namely the NADPH/NADP+ couple and the 2 glutathione/glutathione disulfide couple. On this account, microcrystals of the enzyme were tested as redox probes of intracellular compartments. For introducing protein crystals into human fibroblasts, different methods (microinjection, particle bombardment and optical tweezers) were explored and compared. When glutathione reductase crystals are present in a cytosolic environment, the transition of the yellow Eox form to the orange-red 2-electron reduced charge transfer form, EH2, is observed. Taking into account the midpoint potential of the Eox/EH2 couple, the redox potential of the cytosol was found to be < -270 mV at pH 7.4 and 37 degrees C. As a general conclusion, competent proteins in crystalline--that is signal-amplifying--form are promising probes for studying intracellular events.

Dinitrosyl-dithiol-iron complexes, nitric oxide (NO) carriers in vivo, as potent inhibitors of human glutathione reductase and glutathione-S-transferase.

Human glutathione reductase (GR) and rat liver glutathione-S-transferases (GSTs) had been shown to be inhibited by the nitric oxide (NO) carrier S-nitroso-glutathione (GSNO). We have now extended these studies by measuring the effects of dinitrosyl-iron complexed thiols (DNIC-[RSH]2) on human GR, GST and glutathione peroxidase. DNIC-[RSH]2 represent important transport forms of NO but also of iron ions and glutathione in vivo. Human GR was found to be inhibited by dinitrosyl-iron-di-glutathione (DNIC-[GSH]2) and dinitrosyl-iron-di-L-cysteine (DNIC-Cys2) in two ways: both compounds were competitive with glutathione disulfide (GSSG), the inhibition constant (Ki) for reversible competition of DNIC-[GSH]2 with GSSG being approximately 5 microM; preincubating GR for 10 min with 4 microM DNIC-[GSH]2 and 40 microM DNIC-Cys2, respectively, led to 50% irreversible enzyme inactivation. More than 95% GR inactivation was achieved by incubation with 36 microM DNIC-[GSH]2 for 30 min. This inhibition depended on the presence of NADPH. Absorption spectra of inhibited GR showed that the charge-transfer interaction between the isoalloxazine moiety of the prosthetic group flavin adenine dinucleotide (FAD) and the active site thiol Cys63 is disturbed by the modification. Cys2 and FAD could be ruled out as sites of the modification. Isolated human placenta glutathione-S-transferase and GST activity measured in hemolysates were also inhibited by DNIC-[GSH]2. This inhibition, however, was reversible and competitive with reduced glutathione, the Ki being 20 nM. The inhibition of GST induced by GSNO was competitive with reduced glutathione (GSH) (Ki = 180 microM) and with the second substrate of the reaction, 1-chloro-2,4,-dinitrobenzene (Ki = 170 microM). An inhibition of human glutathione peroxidase by GSNO or DNIC-[RSH]2 was not detectable. Inactivation of GR by DNIC-[GSH]2 is by two orders of magnitude more effective than modification by GSNO; this result and the very efficient inhibition of GST point to a role of DNIC-[RSH]2 in glutathione metabolism.

Review: Fluorescent protein-based tumor models.

Numerous animal models have been developed to provide a deeper insight to tumor progression in the search for new therapeutic leverage. The closer the tumor model represents the real tumor disease, the better. The ideal model provides monitoring, tumor cell detection and quantification, and the physiological events involved in tumor progression and tumor dissemination, simultaneously. Sensitive techniques have been developed which involve fluorescent protein-based methods, developed in order to quantify the tumor cells in a whole organ, and in parallel, to visualize the cells. These genetically encoded fluorescent proteins may also be used to develop biological sensors to monitor the physiological reaction of tumor cells within whole organs in living animals. Here, we aim to review past and present work and to show the perspectives of animal models involving fluorescent protein-transfected tumor cells.

Imaging EGFR phosphorylation in intact human pancreatic carcinoma cells.

BACKGROUND/AIM: Carcinoma of the pancreatic duct is a highly malignant tumor characterized by aggressive and early metastastatic growth. A high rate of tumor recurrence after surgical resection and the lack of effective chemotherapeutic approaches result in low 5-year survival rates. Overexpression of epidermal growth factor (EGF) and its receptor have been correlated to a higher tumor biological aggressiveness. MATERIALS AND METHODS: We investigated EGFR RNA and protein expressions in different pancreatic carcinoma cell lines. EGFR phosphorylation was determined using acceptor photobleaching fluorescence resonance energy transfer (FRET). RESULTS: The imaging method allowed determination of receptor phorphorylation in intact cells without external calibration. Significant differences between the cell lines were found in EGFR expression but not in phosphorylation of EGFR without EGF stimulation. After stimulation with EGF, significant differences were found in receptor phorphorylation. EGFR expression did not correlate with EGFR phorphorylation. CONCLUSION: Since EGFR phosphorylation conveys signal transduction within cells, this molecular imaging method could be useful for the identification of patients with a high level of EGFR phosphorylation within tumor cells and, thus, to select patients for an EGFR-targeted therapy.

Expression of selenium-containing proteins in human colon carcinoma tissue.

Selenium may be beneficial in reducing the risk of cancer incidence and mortality in many cancer types such as liver, prostate, colorectal and lung. However, despite the extensive recent research on selenium and selenium-containing proteins, there are still open questions concerning their expression in certain human cancer types, including colorectal carcinoma. Therefore, the expression level of the selenoproteins thioredoxin reductases 1 and 2 (TRXR-1 and TRXR-2) and glutathione peroxidases 1 and 4 (GPX1 and GPX4) in human colon carcinoma tissues was investigated. Up-regulation of TRXR-1 in the colon carcinoma specimens was found both in disease stage-dependent and independent analyses. No differences were found for TRXR-2 expression levels. GPX1 was up-regulated in carcinoma tissues at both the protein and mRNA levels. GPX4 was also up-regulated at the protein level, except for the samples derived from stage III patients. The expression of TRXR-1, GPX1 and GPX4, but not TRXR-2 is differently regulated in cancer as compared to healthy colonic tissue.

Multimodal treatment of hepatocellular carcinoma (HCC).

Screening of patients at risk for hepatocellular carcinomas (HCC) and preventive virustatic therapy are the first steps in a multimodal treatment concept, because delayed detection leads to a poor prognosis with median survival of <10 months. Surgical resection of HCC is still the treatment of choice in patients with good residual liver function, however, recurrence-free 5-year survival after curative resection is low (33%). In patients with cirrhosis, only 25% of HCC are resectable, limited by low hepatic functional reserve. HCC in patients with non-cirrhotic livers are the domain of extended resections. In newer reports, transplantation in patients with cirrhosis is rated more positively when restricted to patients with solitary nodules <5 cm or up to 3 tumors <3 cm. A new option in HCC therapy are the local methods for tumor ablation, preferably radiofrequency ablation (RFA), especially in patients with limited liver function, non-resectable or multifocal tumors. A new horizon is opened combining these options and multimodal approaches with transarterial chemoembolisation (TACE). This trend to multimodal approaches promises a yet unknown improvement in the prognosis of patients with HCC. Controlled randomized studies comparing and validating the different methods and defining combined treatments according to liver function and tumor stage are eagerly awaited.

HOST-PLANT-INDUCED ASSORTATIVE MATING IN ENCHENOPA TREEHOPPERS.

The hypothesis tested here is whether extrinsic host-plant-induced life-history timing and mating biology promote assortative mating along host-plant lines. In the arboreal, univoltine Enchenopa treehopper system, host plants mediate the timing and synchronization of egg hatch. The result is a uniform age structure with a restricted mating window during which females mate once. Enchenopa on host plants that differ in phenology have asynchronous life histories and mating windows, suggesting that temporal differences may promote assortative mating. To test this hypothesis, egg hatch of Enchenopa from the same host-plant species was manipulated to produce continuous adult age-classes. Under experimental conditions with no spatial barriers, mating occurred between individuals similar in age. The mechanism promoting this assortative mating is differential mortality in males and females, such that few males are still alive when females in successive age-classes mate. Such host-plant-induced assortative mating is viewed as an effective mechanism to protect the integrity of gene pools from migrants, permitting selection for host-plant-adapted genotypes and speciation.

Inhibition of glutathione reductase by dinitrosyl-iron-dithiolate complex.

The biological signal molecule nitric oxide (NO) exists in a free and carrier-bound form. Since the structure of the carrier is likely to influence the interaction of NO with macromolecular targets, we assessed the interaction of a dinitrosyl-iron-dithiolate complex carrying different thiol ligands with glutathione reductase. The enzyme was irreversibly inhibited by dinitrosyl-iron-di-L-cysteine and dinitrosyl-iron-di-glutathione in a concentration- and time-dependent manner (IC50 30 and 3 microM, respectively). Evaluation of the inhibition kinetics according to Kitz-Wilson yielded a Ki of 14 microM, and a k3 of 1.3 x 10(-3) s-1. A participation of catalytic site thiols in the inhibitory mechanism was indicated by the findings that only the NADPH-reduced enzyme was inhibited by dinitrosyl-iron complex and that blockade of these thiols by Hg2+ afforded protection against irreversible inhibition. This inhibition was not accompanied by formation of a protein-bound dinitrosyl-iron complex and/or S-nitrosation of active site thiols (Cys-58 and Cys-63). However, one NO moiety exhibiting an acid lability similar to a secondary N-nitrosamine was present per mol of inhibited monomeric enzyme. These findings suggest specifically N-nitrosation of glutathione reductase as a likely mechanism of inhibition elicited by dinitrosyl-iron complex and demonstrate in general that structural resemblance of an NO carrier with a natural ligand enhances NO+ transfer to the ligand-binding protein.

Enzyme inactivation through sulfhydryl oxidation by physiologic NO-carriers.

Nitric oxide (NO) is a pluripotent regulatory molecule, yet the molecular mechanisms by which it exerts its effects are largely unknown. Few physiologic target molecules of NO have been identified, and even for these, the modifications caused by NO remain uncharacterized. Human glutathione reductase (hGR), a central enzyme of cellular antioxidant defense, is inhibited by S-nitrosoglutathione (GSNO) and by diglutathionyl-dinitroso-iron (DNIC-[GSH]2), two in vivo transport forms of NO. Here, crystal structures of hGR inactivated by GSNO and DNIC-[GSH]2 at 1.7 A resolution provide the first picture of enzyme inactivation by NO-carriers: in GSNO-modified hGR, the active site residue Cys 63 is oxidized to an unusually stable cysteine sulfenic acid (R-SOH), whereas modification with DNIC-[GSH]2 oxidizes Cys 63 to a cysteine sulfinic acid (R-SO2H). Our results illustrate that various forms of NO can mediate distinct chemistry, and that sulfhydryl oxidation must be considered as a major mechanism of NO action.