A theoretical study of lipid accumulation in the liver-implications for nonalcoholic fatty liver disease.

A hallmark of the nonalcoholic fatty liver disease is the accumulation of lipids. We developed a mathematical model of the hepatic lipid dynamics to simulate the fate of fatty acids in hepatocytes. Our model involves fatty acid uptake, lipid oxidation, and lipid export. It takes into account that storage of triacylglycerol within hepatocytes leads to cell enlargement reducing the sinusoids radius and impairing hepatic microcirculation. Thus oxygen supply is reduced, which impairs lipid oxidation. The analysis of our model revealed a bistable behavior (two stable steady states) of the system, in agreement with histological observations showing distinct areas of lipid accumulation in lobules. The first (healthy) state is characterized by intact lipid oxidation and a low amount of stored lipids. The second state in our model may correspond to the steatotic cell; it is marked by a high amount of stored lipids and a reduced lipid oxidation caused by impaired oxygen supply. Our model stresses the role of insufficient oxygen supply for the development of steatosis. We discuss implications of our results in regard to the experimental design aimed at exploring lipid metabolism reactions under steatotic conditions. Moreover, the model helps to understand the reversibility of lipid accumulation and predicts the reversible switch to show hysteresis. The system can switch from the steatotic state back to the healthy state by reduction of fatty acid uptake below the threshold at which steatosis started. The reversibility corresponds to the observation that caloric restriction can reduce the lipid content in the liver.

Modifications in integrin expression and extracellular matrix composition in children with biliary atresia.

BACKGROUND: The aetiology of biliary atresia (BA) is still unresolved. The study's aim was to investigate the distribution of extracellular matrix proteins and cellular adhesion molecules in children with BA compared to other cholestatic liver disease (CLD) and normal liver architecture (NLA). PATIENTS: Liver biopsies were obtained from children with BA (n=13), CLD (n=6) and NLA (n=8). METHOD: We systematically analysed ultra thin frozen sections from the liver hilum stained with 25 monoclonal antibodies for cellular characterisation, extracellular matrix proteins and adhesion molecules. RESULTS: 2 changes were specifically found in BA: laminin beta1 was reduced in children with BA vs. NLA and CLD. Conversely, integrin alpha 3 was increased in BA vs. NLA and CLD (p<0.05). Furthermore, we detected changes in a similar pattern for both BA and CLD vs. NLA: in BA and CLD perlecan was increased. On the contrary, integrin beta1 and entactin were decreased vs. NLA (p<0.05). DISCUSSION: Extracellular matrix proteins and adhesion molecules mediate cellular polarity and integrity, development of tubular structures, and proliferation. Therefore, our findings can be important for the understanding of the genesis of BA. CONCLUSION: The composition of extracellular matrix proteins and adhesion molecules in children with BA differs from NLA and other CLD in distribution of laminin beta1 and integrin alpha 3, which may have implications for genetic, immunologic and environmental associations in BA.

MALDI imaging-based classification of hepatocellular carcinoma and non-malignant lesions in fibrotic liver tissue.

Histopathologic differentiation of nodular lesions in cirrhotic liver is difficult even for experienced hepatopathologists especially regarding diagnosis of hepatocellular carcinoma (HCC) in biopsies. For this reason, new tissue markers are needed to reinforce histopathologic decision-making. With advances in molecular techniques, proteomic analysis may help to confirm the diagnosis of HCC. Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) is a powerful technology which allows to determine and to localize proteins directly in tissue sections. Using MALDI IMS proteomic patterns of cryosections with lesions of HCC (n = 15) and non-malignant fibrotic liver tissue (n = 11) were investigated to establish a classification model of HCC, which was validated in an independent set of tissue to distinguish HCC (n = 10) from regenerative nodules (n = 8). By correlating generated mass spectrometric images with the histology of the tissue sections we found that the expression of 4 proteins as indicated by m/z 6274, m/z 6647, m/z 6222 and m/z 6853 was significantly higher in HCC tissue than in non-tumorous liver tissue. The generated classification model based on the most significant 3 differentially expressed proteins allowed a reliable prediction of benign and malignant lesions in fibrotic liver tissue with a sensitivity and specificity of 90 % in the validation set. The identified MALDI IMS proteomic signature can be diagnostically helpful to allow simplifying the diagnostic process and minimize the risks of delays in establishing the objective final diagnosis and initiating treatment of patients with HCC.

Fulminant gastrointestinal bleeding caused by EBV-triggered hemophagocytic lymphohistiocytosis: report of a case.

Hemophagocytic lymphohistiocytosis (HLH) is a rare and often fatal hyperinflammatory syndrome characterized by fever, cytopenia, dramatically increased ferritin and hepatosplenomegaly. Here, we describe a previously healthy 39 year old pregnant woman in 30th week of her pregnancy with diarrhoea, intermittent gastrointestinal bleeding and fever of unknown focus. After cesarean section of twins in the 31st week she deteriorated with fulminant upper and lower gastrointestinal bleeding and disseminated intravascular coagulation. Gastro-, ileocolonoscopy and capsule endoscopy identified multiple bleeding punched ulcerations in the stomach, the entire small bowel and in parts of the colon. Emergency surgery with intraoperative endoscopy for uncontrolled hemorrhagic shock resulted in the resection of actively bleeding ulcers in the jejunum which temporally stabilized the critically ill patient. Jejunal histology and in situ hybridisation showed extensive ulcerations, focal lymphohistiocytic infiltration and EBV-positive immunoblasts. The diagnosis fulminant EBV-related HLH was confirmed based on the HLH-2004 diagnostic criteria and through detection of a reactivated EBV infection (up to 3 × 10(7) DNA copies/mL serum). Despite immunosuppressive therapy with steroids, cyclosporine A and etoposide in combination with Rituximab, the patient died from this sepsis-like, hyper-inflammatory syndrome in multiorgan failure with uncontrolled bleeding.

How similar are inbred rats? The influence of anatomical variations, shipment and sampling time on experimental surgery.

Variations among inbred rats in terms of anatomy and routine laboratory values can potentially blur surgical experimental results. Therefore, a retrospective analysis aiming at investigating hepatic and perihepatic anatomical variations, liver weight, body weight, liver weight/body weight ratio (LBWR), variations in routine laboratory values, and the influence of shipment and repeated sampling was performed. In our study, liver weight of rats seemed to be strain-specific. LBWR was weakly and negatively correlated with body weight in rats. A statistically significant difference in routine blood tests was found among normal rats grouped by different body weight or shipment. Weekly repeated sampling from the same rats revealed a statistically significant difference in a blood test. In conclusion, the fact that variation among rats or their environment can blur the results of a surgical experimental study should be kept in mind.

Hepatic arterial perfusion is essential for the spontaneous recovery from focal hepatic venous outflow obstruction in rats.

We previously observed that focal hepatic venous outflow obstruction recovered spontaneously by the formation of sinusoidal canals in a rat model of portal hyperperfusion. We aimed to investigate whether the lack of hepatic arterial perfusion aggravates parenchymal damage, decelerates recovery and influences the formation of sinusoidal canals after focal hepatic venous outflow obstruction. Rats were subjected to arterialized versus nonarterialized syngeneic liver transplantation after ligating the right median hepatic vein in the donor. Hepatic damage, microcirculation, regeneration and vascular remodeling were evaluated. In arterialized-recipients, confluent necrosis interspersed with viable periportal islands of hepatocytes, and vascularized sinusoidal canals with visible blood flow, surrounded by normal sinusoidal structure, were visible on postoperative day (POD) 2. Complete parenchymal recovery was consequently established by resorption of necrosis and hepatocyte proliferation, detected in viable portal islands and border zone. Lack of hepatic arterial perfusion caused complete necrosis in the obstruction zone without viable hepatocytes in the periportal area on POD2. Hepatocyte proliferation was only visible in the border zone. On POD28, perfused vascular structures, without neighboring normal sinusoidal structures, were observed in the scar-like area. Hepatic arterial perfusion determined the extent of hepatic necrosis, the formation of vascularized sinusoidal canals and the parenchymal recovery, after focal hepatic venous outflow obstruction.

A novel end-to-side anastomosis technique for hepatic rearterialization in rat orthotopic liver transplantation to accommodate size mismatches between vessels.

BACKGROUND/AIMS: We present our modification of a sutured arterial anastomosis in orthotopic rat liver transplantation as well as a literature survey and analysis of the existing techniques of rearterialization with regard to technical difficulties and potential limitations. METHODS: The donor common hepatic artery (CHA) was anastomosed to the enlarged lumen of the recipient proper hepatic artery (PHA), tailored to match the size of the donor CHA, with an end-to-side interrupted suture technique. Vascular patency of hepatic rearterialization was assessed both intraoperatively and at the time the liver grafts were harvested (postoperative days 2 and 28). The effect of arterialization on hepatic morphology was confirmed by histological examination and compared to nonarterialized rat orthotopic liver transplantation. RESULTS: The CHAs had a significantly larger diameter (up to 3-fold) compared to the PHAs, which represents a considerable size mismatch. The anastomosis procedure including the size adaptation required 15-25 min. All anastomoses were patent immediately, 5 min after rearterialization and at both harvest time points. The liver lobular architecture was intact in the rearterialized group, whereas a moderate degree of bile duct proliferation and portal/lobular lymphocytic infiltration were observed in the nonarterialized group. CONCLUSION: The new technique is a time-consuming and microsurgically challenging but universally applicable and robust procedure accommodating even a substantial mismatch in vessel diameter.

Modulation of keratinocyte growth factor and its receptor in reepithelializing human skin.

We investigated the expression and distribution of keratinocyte growth factor (KGF) (FGF-7) and its receptor (KGFR) during reepithelialization of human skin. KGF mRNA levels increased rapidly by 8-10-fold and remained elevated for several days. In contrast, KGFR transcript levels decreased early but were significantly elevated by 8-9 d. A KGF-immunoglobulin G fusion protein (KGF-HFc), which specifically and sensitively detects the KGFR, localized the receptor to differentiating keratinocytes of control epidermis, but revealed a striking decrease in receptor protein expression during the intermediate period of reepithelization. Suramin, which blocked KGF binding and stripped already bound KGF from its receptor, failed to unmask KGFRs in tissue sections from the intermediate phase of wound repair. The absence of KGFR protein despite increased KGFR transcript levels implies functional receptor downregulation in the presence of increased KGF. This temporal modulation of KGF and KGFRs provides strong evidence for the functional involvement of KGF in human skin reepithelialization.

Effect and risk of AEE788, a dual tyrosine kinase inhibitor, on regeneration in a rat liver resection model.

BACKGROUND: AEE788, a dual tyrosine kinase inhibitor, has antiproliferative effects on diverse tumor models in mice. We aimed to investigate whether AEE788 blocks liver regeneration and causes drug-related side effects. METHODS: Rats treated orally with 50 mg/kg AEE788 or solvent every 2 days were subjected to 70% partial hepatectomy (PH) and sacrificed on postoperative days 1, 2, 7, and 28. Liver regeneration was evaluated using liver weight to body weight ratio, BrdU-staining, mitotic index, and PCR for PCNA (proliferating cell nuclear antigen). Side effects on the gastrointestinal system and liver were assessed using clinical chemistry, histology, silver staining, and immunohistochemistry. Plasma and liver tissue levels of AEE788 were measured using spectrometry. RESULTS: AEE788 treatment did not inhibit liver regeneration. No obvious drug-related systemic or hepatic side effects were observed. Restoration of liver architecture during liver regeneration was not obviously impaired, even after 4 weeks' AEE788 treatment. After a 1-week treatment, AEE788 concentrations in plasma and liver tissue in the PH group were 3-fold and 8-fold higher than the non-PH group, respectively. CONCLUSION: Its antiproliferative properties, good tolerance, and lack of inhibition on liver regeneration make AEE788 a potential candidate for clinical study with oncological PH, but one that carries the risk of overexposure in the early postoperative phase.

Specific receptor detection by a functional keratinocyte growth factor-immunoglobulin chimera.

Fibroblast growth factor receptors (FGFRs) are encoded by at least four distinct highly conserved genes, and alternative splicing generates multiple gene products. The close relationship among different FGFRs has greatly increased the difficulty in generating specific immunochemical probes. As an alternative strategy, we constructed a fusion protein comprising keratinocyte growth factor (KGF) and an IgG1 Fc domain (HFc). The chimeric molecule was efficiently secreted from transfectants as a disulfide-linked dimer that bound KGFRs with high affinity. Moreover, the KGF-HFc, like native KGF, induced DNA synthesis by epithelial cells implying normal functional receptor activation. Because it retained the convenient detection properties of an immunoglobulin, it was possible to use the KGF-HFc in ligand-mediated histochemical analysis of KGFRs. Flow cytometry revealed KGF-HFc chimera detection of the KGFR, an alternative FGFR2 product, but not FGFR1 (flg) or FGFR2 (bek). Histochemical analysis of normal skin demonstrated the specific localization of KGFRs within the spinous layer, a zone of epithelial cell differentiation. KGFRs were also localized to epithelial cells within a specific region of the hair follicle, and they were not detectable in cells of the sweat gland. Tissue sections of soft palate and tonsil, two examples of nonkeratinizing epithelium, revealed staining of stratum spinosum and some staining of the basal cell layer as well. Neither salivary gland epithelium nor lymphoid cells were positive. The ciliated epithelium of the trachea exhibited KGFR expression in intermediate and basal cell layers. In striking contrast to the normal pattern of staining in the adjacent epithelium, a squamous cell carcinoma of skin lacked detectable KGFRs. Our present findings suggest that growth factor-Ig fusion proteins may be generally applicable in ligand-mediated histochemical detection and localization of growth factor receptors.

Median liver lobe of woodchuck as a model to study hepatic outflow obstruction: a pilot study.

BACKGROUND: Hepatic vein outflow obstruction represents an important clinical problem in living-liver transplantation. An animal model is required to study the influence of outflow obstruction on the intrahepatic regulation of liver perfusion and the subsequent effects on liver injury and recovery during liver regeneration. The size of woodchucks enables the use of standard clinical imaging procedures. AIM: This study aims at describing hepatic vascular and territorial anatomy of the woodchuck liver based on a virtual three-dimensional (3D) visualization of the hepatic vascular tree. METHODS: Woodchucks (n=6) were subjected to an all-in-one computed tomography (CT) after contrasting the vascular and the biliary tree. CT-images were used for 3D-reconstruction of hepatic and portal veins and calculation of the corresponding portal and hepatic vein territories and their respective volume using hepavision (MeVisLab). A virtual resection was performed following the Cantlie-line and territories at risk were calculated. RESULTS: The median lobe of the woodchuck liver has a similar vascular supply and drainage as the human liver with two portal (right and left median portal vein) and three hepatic veins (left, middle and right median hepatic vein). The corresponding portal and hepatic vein subterritories are of a similar relative size compared with the human liver. Virtual splitting of the median lobe of the woodchuck liver revealed areas at risk of focal outflow obstruction, as observed clinically. CONCLUSION: The median liver lobe of the woodchuck represents, to a small extent, the hepatic vascular anatomy of the human liver and is therefore a suitable potential model to correlate repeated imaging of impaired liver perfusion with histomorphological findings of liver damage and regeneration.

[Knowledge, trust, and the decision to donate organs : A comparison of medical students and students of other disciplines in Germany]. / Wissen, Vertrauen und Entscheidung zur Organspende : Ein Vergleich zwischen Medizinstudenten und Studenten anderer Fachrichtungen.

BACKGROUND: Following the organ transplant scandal in Germany in 2011, the willingness to donate organs postmortem decreased dramatically. This was explained by a loss of confidence in the German organ donation system. OBJECTIVES: The aim of this study was to evaluate the relationship between knowledge, trust, and fear in respect to organ donation and the explicit willingness to potentially act as an organ donor by comparing medical students to students of other disciplines. MATERIAL AND METHODS: We conducted a Facebook-based online survey (June-July 2013). The participating students were divided into two groups according to their discipline: medical students and other students. Based on questions covering different aspects of organ donation, a knowledge, trust, and fear score was established and calculated. The answers were related to an explicitly expressed decision to donate organs as expressed in a signed organ donor card. RESULTS: In total, 2484 participants took part in our survey. Of these, 1637 were students, 83.7% (N = 1370) of which were medical students and 16.3% (N = 267) other students. As expected, medical students reached a higher knowledge score regarding organ donation compared with other students (knowledge score 4.13 vs. 3.38; p < 0.001). They also demonstrated more confidence in organ donation, resulting in a higher confidence score (3.94 vs. 3.33; p < 0.001) and expressed less fear towards organ donation as indicated by the lower fear score (1.76 vs. 2.04; p < 0.01). Medical students declared their written willingness to donate organs more often than did other students (78.2% vs. 55.2%; p < 0.001). Entries on organ donation cards did not differ significantly between medical students and other students. Medical students possessing an organ donor card showed a higher knowledge and a higher trust score than did medical students without an organ donor card. In contrast, other students possessing an organ donor card showed a higher trust score but did not show a higher knowledge score. CONCLUSIONS: The higher level of knowledge and trust demonstrated by the medical students was associated with a higher rate of written decisions to donate organs. In contrast, the lower level of knowledge and trust observed in the non-medical students was associated with a lower rate of organ donor cards. Interestingly, in the group of non-medical students, the decision regarding organ donation was associated with a higher level of trust, but not with a higher level of knowledge. It would appear that knowledge, trust, and the decision to donate organs are closely related. In cases of a low level of knowledge, confidence is even more important. Therefore, organ donation campaigns should focus on increasing knowledge and fostering trust.

Modulation of hepatic perfusion did not improve recovery from hepatic outflow obstruction.

BACKGROUND: Focal hepatic venous outflow obstruction frequently occurs after extended liver resection and leads to a portal hypertension, arterial hypoperfusion and parenchymal necrosis. In this study, we investigated the pharmacological modulation of liver perfusion and hepatic damage in a surgical model of hepatic outflow obstruction after extended liver resection by administration of 5 different drugs in comparison to an operative intervention, splenectomy. METHODS: Male inbred Lewis rats (Lew/Crl) were subjected to right median hepatic vein ligation + 70% partial hepatectomy. Treatment consisted of a splenectomy or the application of saline, carvedilol or isosorbide-5-mononitrate (ISMN) (5 mg · kg-1 respectively 7,2 mg · kg-1 per gavage 12 h-1). The splenectomy was performed during operation. The effect of the treatments on hepatic hemodynamics were measured in non-operated animals, immediately after operation (n = 4/group) and 24 h after operation (n = 5/group). Assessment of hepatic damage (liver enzymes, histology) and liver cell proliferation (BrdU-immunohistochemistry) was performed 24 h after operation. Furthermore sildenafil (10 µg · kg-1 i.p. 12h-1), terlipressin (0.05 mg · kg-1 i.v. 12 h-1) and octreotide (10 µg · kg-1 s.c. 12 h-1) were investigated regarding their effect on hepatic hemodynamics and hepatic damage 24 h after operation (n = 4/group). RESULTS: Carvedilol and ISMN significantly decreased the portal pressure in normal non-operated rats from 11,1 ± 1,1 mmHg (normal rats) to 8,4 ± 0,3 mmHg (carvedilol) respectively 7,4 ± 1,8 mmHg (ISMN). ISMN substantially reduced surgery-induced portal hypertension from 15,4 ± 4,4 mmHg to 9,6 ± 2,3 mmHg. Only splenectomy reduced the portal flow immediately after operation by approximately 25%. No treatment had an immediate effect on the hepatic arterial perfusion. In all treatment groups, portal flow increased by approximately 3-fold within 24 h after operation, whereas hepatic arterial flow decreased substantially. Neither treatment reduced hepatic damage as assessed 24 h after operation. The distribution of proliferating cells appeared very similar in all drug treated groups and the splenectomy group. CONCLUSION: Transient relative reduction of portal pressure did not result in a reduction of hepatic damage. This might be explained by the development of portal hyperperfusion which was accompanied by arterial hypoperfusion.

Large nontransplanted hepatocellular carcinoma in woodchucks: treatment with adenovirus-mediated delivery of interleukin 12/B7.1 genes.

BACKGROUND: Cytokine-based gene therapy strategies efficiently stimulate immune responses against many established transplanted tumors, leading to rejection of the tumor. In this study, we investigated the therapeutic potential of cancer immunotherapy in a clinically more relevant model, woodchucks with primary hepatocellular carcinomas induced by woodchuck hepatitis virus. METHODS: Large (2-5 cm), established intrahepatic tumors were given an injection once with 1 x 10(9) plaque-forming units of AdIL-12/B7.1, an adenovirus vector carrying genes for murine interleukin 12 and B7.1, or of AdEGFP, the control virus, and regression of the tumors was then monitored. Five animals were used in total. RESULTS: In four tumor-bearing animals, the antitumor response was assessed by autopsy and histologic analysis within 1-2 weeks after treatment. In all animals treated with AdIL-12/B7.1 therapy versus AdEGFP therapy, we observed substantial tumor regression (P =.006; two-sided unpaired Student's t test) accompanied by a massive infiltration of T lymphocytes. These tumors also contained increased levels of CD4(+) and CD8(+) T cells and interferon gamma (IFN gamma). In continuously growing tumor nodules given an injection of the control virus or in nontumoral liver, no such effects (i.e., tumor regression and increased levels of CD4(+) and CD8(+) T cells and IFN gamma) were detected. In the fifth animal, monitored for long-term antitumor efficacy by magnetic resonance imaging (MRI) after intratumoral vector administration by MRI guidance, the tumor was almost completely eliminated (> or = 95%) 7 weeks after treatment. CONCLUSION: Adenovirus vector-based immunotherapy appears to be an effective treatment of large nontransplanted (orthotopic) tumors that acquire malignant characteristics in a stepwise process, reflecting the real-world scenario of hepatocellular carcinoma in humans.

[Liver engineering as a new source of donor organs : A systematic review]. / "Liver engineering" als neue Quelle von Spenderorganen : Eine systematische Übersichtsarbeit.

BACKGROUND: Organ engineering is a new strategy to cope with the shortage of donor organs. A functional scaffold from explanted organs is prepared by removing all cellular components (decellularization) and the reseeding (repopulation) of the organ scaffold to generate a functional organ in vitro for transplantation. This technique was also applied to the liver (liver engineering). OBJECTIVES: Outline of the current state of the art and resulting approaches for future research strategies. MATERIAL AND METHODS: Systematic review according to the PRISMA guidelines: a PubMed-based literature search (search terms liver, decellularization), selection of relevant articles based on predetermined criteria for relevance (e.g. decellularization, repopulation and transplantation), extraction and critical appraisal of data and results concerning the conditions for decellularization, repopulation and transplantation. RESULTS: Decellularization was successfully performed in small and large animal models. Hepatocytes as well as stem cells and hepatic cell lines were applied for repopulation and 7 publications could show the successful transplantation of acellular and repopulated organ scaffolds. The current scientific need for further studies concerning the source of donor organs, optimization of the decellularization process, the cell type for the reseeding process and the establishment of the optimal conditions for the repopulation of the scaffold is still tremendous. For successful recellularization of the liver three goals need to be achieved: (1) reseeding of the organ scaffold with a sufficient amount of parenchymal cells, (2) endothelialization of the vascular tree to ensure the supply of oxygen and nutrients to parenchymal cells and (3) an appropriate epithelialization of the biliary tree. In order to progress to clinical trials a suitable transplantation model to verify the function of the organ constructs must be established. CONCLUSION: Liver engineering using biological cell-free organ scaffolds represents a scientific and ethical challenge. The existing results emphasize the potential of this new and promising strategy to create organs for transplantation in the future.

Balloon-protected carotid artery stenting: relationship of periprocedural neurological complications with the size of particulate debris.

BACKGROUND: Carotid artery stenting (CAS) has been advocated as an alternative to endarterectomy. To prevent cerebral atheroembolism during CAS, distal balloon occlusion of the target artery increasingly is employed during the procedure. A correlation of the size of captured particles with the incidence of periprocedural neurological complications (PNCs) has not been attempted. METHODS AND RESULTS: In a 4-center, phase-1 trial, 54 patients (46 men; age, 69+/-8 years) underwent 58 CAS procedures using the PercuSurge GuardWire system for distal protection. Aspirated debris was sent for histological/cytological analysis. Stent placement was successful in all cases. Mean balloon occlusion time was 10.4+/-4.0 minutes (range, 3.0 to 22.0 minutes). Three patients (5.2%) experienced PNCs: 1 prolonged reversible ischemic neurological deficit that resolved in /=10 000 micrometer(2)) were found in 48 aspirates (83%). The median number of particles, their maximum diameter, and their maximum area were all significantly higher in the aspirates obtained during procedures associated with PNCs than in aspirates obtained during procedures not associated with PNCs. However, pronounced overlap in the distributions (PNCs versus no PNCs) of the number and maximum diameter of particles precluded any predictive inferences. In contrast, a maximum particle area >800 000 micrometer(2) (>0.8 mm(2)) was associated with a 60% chance of having a PNC. CONCLUSIONS: Despite balloon protection, PNCs occurred in 5.2% of patients who underwent CAS procedures. The maximum area of aspirated particles seems to be an indicator of increased risk for PNCs.

Stent coating with titanium-nitride-oxide for reduction of neointimal hyperplasia.

BACKGROUND: Coronary stents prevent constrictive arterial remodeling but stimulate neointimal hyperplasia. Stainless steel induces a metallic foreign body reaction, which is absent for titanium. The hypothesis of the present study was that titanium renders the stent surface biologically inert, with reduced platelet and fibrinogen binding. METHODS AND RESULTS: Twelve pigs were instrumented with a stainless steel and 2 titanium-nitride-oxide-coated stents (TiNOX 1, ceramic; TiNOX 2, metallic). Animals were restudied after 6 weeks. Histological specimens of stented segments were analyzed by digital morphometry. Platelet adhesion and fibrinogen binding studies were performed in the perfusion chamber. Under in vitro conditions, TiNOX 1 showed reduced platelet adhesion (65+/-3%) compared with TiNOX 2 (72+/-5%; P<0.05) and stainless steel (71+/-4%; P<0.05). Platelet adhesion 48 hours after incubation with human plasma, however, was not different between TiNOX 1 (17+/-3%) and 2 (15+/-3%) but was significantly higher with stainless steel (23+/-2%; P<0.05). Fibrinogen binding was significantly reduced with TiNOX 2 (54+/-3%) compared with TiNOX 1 (82+/-4%, P<0.05) or stainless steel (100%, P<0.05). Histomorphometry revealed a significantly larger neointimal area in stainless steel (2.61+/-1.12 mm(2)) than in TiNOX 1-coated (1.47+/-0.84 mm(2), P<0.02) or TiNOX 2-coated (1.39+/-0.93 mm(2), P<0.02) stents. The reductions were 44% and 47%, respectively. CONCLUSIONS: TiNOX coating significantly reduces neointimal hyperplasia in stainless steel stents. The antiproliferative effect was similar for both TiNOX coatings, suggesting that the electrochemical properties are more important for attenuation of neointimal proliferation than the observed differences in platelet adhesion and fibrinogen binding.

Modeling function-perfusion behavior in liver lobules including tissue, blood, glucose, lactate and glycogen by use of a coupled two-scale PDE-ODE approach.

This study focuses on a two-scale, continuum multicomponent model for the description of blood perfusion and cell metabolism in the liver. The model accounts for a spatial and time depending hydro-diffusion-advection-reaction description. We consider a solid-phase (tissue) containing glycogen and a fluid-phase (blood) containing glucose as well as lactate. The five-component model is enhanced by a two-scale approach including a macroscale (sinusoidal level) and a microscale (cell level). The perfusion on the macroscale within the lobules is described by a homogenized multiphasic approach based on the theory of porous media (mixture theory combined with the concept of volume fraction). On macro level, we recall the basic mixture model, the governing equations as well as the constitutive framework including the solid (tissue) stress, blood pressure and solutes chemical potential. In view of the transport phenomena, we discuss the blood flow including transverse isotropic permeability, as well as the transport of solute concentrations including diffusion and advection. The continuum multicomponent model on the macroscale finally leads to a coupled system of partial differential equations (PDE). In contrast, the hepatic metabolism on the microscale (cell level) was modeled via a coupled system of ordinary differential equations (ODE). Again, we recall the constitutive relations for cell metabolism level. A finite element implementation of this framework is used to provide an illustrative example, describing the spatial and time-depending perfusion-metabolism processes in liver lobules that integrates perfusion and metabolism of the liver.

Complete evaluation of adrenal tumours in a tertiary care institution in Thuringia, Germany.

INTRODUCTION AND OBJECTIVE: Adrenal tumours, mainly incidentalomas, are an increasingly common clinical and diagnostic challenge. The aim of the present study was the retrospective evaluation of all patients with adrenal tumours treated in our university department from 1.1.1999-31.12.2013 PATIENTS AND METHODS: 187 patients (108 females: 79 males, mean age 57.7 years) were found to have adrenal tumours in our institution during the study period. All patients underwent basic and, when indicated, advanced analytical testing for hormonal activity. Tumours were classified according to patients' gender, age at diagnosis, tumour localization and size, as well as benignity and malignancy when postinterventional histopathological examination was conducted. RESULTS: 134 (71.7%) patients had non-hormone secreting tumours, 17 (9.1%) pheochromocytoma, 13 (7.0%) Conn-syndrome, 13 (7.0%) adrenal Cushing's disease, 1 congenital adrenal hyperplasia and 2 sexual hormone-secreting tumours. 7 (3.7%) tumours could not be definitively classified due to unclear or marginal test-results. Cushing's disease was more prevalent in females (11 females: 2 males). 163 (87.2% of the total cohort) tumours were unilateral [95 (50.8%) left; 68 (36.4%) right] and 24 (12.8%) were bilateral. Tumour size was <3 cm in 109 (58.3%), 3-6 cm in 63 (33.7%) and >6 cm in 15 (8.0%) patients. 60 (32.1%) patients underwent adrenalectomy, thereof 88.9% of the patients with hormonally active tumours, while 8 (4.3%) were evaluated with ultrasound-guided biopsy. Malignancy was confirmed in 10 individuals (5.3%; 3 non-functioning tumours, 3 pheochromocytomas, 2 Cushing's patients and 2 sexual-hormone secreting tumours), while 2 surgical specimens with histopathological diagnosis of pheochromocytoma showed signs of malignant changes. Benignity was histopathologically confirmed in 55 patients. CONCLUSIONS: The prevalence of detected adrenal tumours is rising due to widely available and applied abdominal imaging procedures. The vast majority of them are benign, of small size (<3 cm) and hormonally inactive. Adrenalectomy is the therapeutic method of choice in big and/or confirmed hormone-secreting tumours.

Classification and prediction of HCC tissues by Raman imaging with identification of fatty acids as potential lipid biomarkers.

PURPOSE: Patients with hepatocellular carcinoma (HCC) can only be treated curatively at early stages and then have a favorable prognosis of this often fatal disease. For this reason, an early detection and diagnostic confirmation are crucial. Raman imaging spectroscopy is a promising technology for high-resolution visualization of the spatial distribution of molecular composition in tissue sections. The aim of this study was to investigate molecular information of liver tissue by Raman imaging for classification and diagnostic prediction. METHODS: Unstained cryosections of human hepatic tissues (23 patients) were measured by Raman spectroscope in the regions of HCC (n = 12) and fibrosis (n = 17). The acquired data set was used to generate a random forest classification model with 101 iterations of sevenfold cross-validation. The models obtained during cross-validation were also used to predict regions of tumor margin (n = 8) aside from independent testing. RESULTS: Raman spectra differed between malignant and non-malignant tissue regions. Based on these spectral data, a random forest classification model calculated a prediction accuracy of 86 % (76 % sensitivity and 93 % specificity). The ten most important variables were identified at 2895, 2856, 1439, 1298, 1080, 1063, 1023, 937, 920, and 719 cm(-1). CONCLUSIONS: In this study, Raman imaging spectroscopy was applied successfully for liver tissue to differentiate, classify, and predict with high accuracy malignant and non-malignant tissue regions. Furthermore, the most important differences were identified as the Raman signature of fatty acids. The demonstrated results highlight the enormous potential which vibrational spectroscopy techniques have for the future diagnostics and prognosis estimation of HCC.