Hypoxia-Inducible Transgelin-2 Confers Treatment Resistance through Activation of PI3K/Akt/GSK3β Pathway in Glioblastoma

PURPOSE/OBJECTIVE(S)

Glioblastoma (GBM) patients with wild-type IDH experience worse survival response to the standard treatment of surgery followed by radiation therapy (RT) and temozolomide (TMZ) chemotherapy compared to their mutant IDH counterparts. This treatment has remained relatively ineffective partly due to the highly invasive phenotype of GBM leading to therapeutic resistance and tumor recurrence. Hypoxia is one of the key characteristic features of GBM which results in cancer metastasis and confers treatment resistance. Therefore, it is paramount to identify targets to help overcome hypoxia-induced treatment resistance in glioblastoma. Our lab has identified transgelin-2 (TAGLN2) to be significantly upregulated in IDH-wt GBM through multiple molecular profiling studies. This study aims to understand the mechanisms by which TAGLN2 confers treatment resistance for developing additional treatments for GBM. Additionally, active drug development efforts are also underway to target TAGLN2 for circumventing these therapeutic resistance mechanisms for effective GBM therapy.

MATERIALS/METHODS

RNAi-mediated TAGLN2 knockdown (KD) approach was employed to assess the functions of TAGLN2 in GBM patient-derived xenograft (PDX) cell lines. Series of in vitro functional assays were performed to assess the role of TAGLN2 in these cell lines. Cell proliferation, invasion ± RT and/or TMZ were assessed by MTS and Trans-well invasion assays. Subsequently, WB analysis of oncogenic signaling pathways was performed following Transgelin-2 KD. Co-IP assays and Biacore/SPR analyses were performed to study the binding affinity and kinetics for the interaction of PTEN with TAGLN2. Further, cells were intracranially implanted in nude mice to assess the role of TAGLN2 on tumor growth in vivo.

RESULTS

Conditional KD of TAGLN2 reduces cell proliferation, survival and invasive potential of GBM PDX cell lines. TAGLN2 KD also improved the sensitivity of these cells to both TMZ and radiation in vitro, as assessed by proliferation, survival, clonal expansion, and invasion. Histopathological studies of human GBM tumors and mouse xenograft tumors showed elevated expression of TAGLN2 in the peri-necrotic region of the tumors indicating that TAGLN2 protein level was upregulated by hypoxia. We also show that TAGLN2 is induced in hypoxic microenvironments with GBM PDX cell lines and its overexpression may enhance cellular resistance towards conventional therapy. Subsequently, we also show that hypoxia-induced TAGLN2 activates the PI3K/Akt oncogenic pathway through binding and inhibition of PTEN. Finally, in vivo data using an orthotopic xenograft mouse model shows reduction of tumor growth with knockdown of TAGLN2.

CONCLUSION

Our in vitro and in vivo xenograft studies suggest that TAGLN2 confers treatment resistance to GBM contributing to tumor recurrence. Altogether, TAGLN2 may serve as a potential therapeutically vulnerable target in GBM specifically through its role in cell survival and invasion.

Hypoxia-induced downregulation of microRNA-186-5p in endothelial cells promotes non-small cell lung cancer angiogenesis by upregulating protein kinase C alpha

The tumor microenvironment stimulates the angiogenic activity of endothelial cells (ECs) to facilitate tumor vascularization, growth, and metastasis. The involvement of microRNA-186-5p (miR-186) in regulating the aberrant activity of tumor-associated ECs has so far not been clarified. In the present study, we demonstrated that miR-186 is significantly downregulated in ECs microdissected from human non-small cell lung cancer (NSCLC) tissues compared with matched non-malignant lung tissues. In vitro analyses of primary human dermal microvascular ECs (HDMECs) exposed to different stimuli indicated that this miR-186 downregulation is triggered by hypoxia via activation of hypoxia-inducible factor 1 alpha (HIF1α). Transfection of HDMECs with miR-186 mimic (miR-186m) significantly inhibited their proliferation, migration, tube formation, and spheroid sprouting. In contrast, miR-186 inhibitor (miR-186i) exerted pro-angiogenic effects. In vivo, endothelial miR-186 overexpression inhibited the vascularization of Matrigel plugs and the initial growth of tumors composed of NSCLC cells (NCI-H460) and HDMECs. Mechanistic analyses revealed that the gene encoding for protein kinase C alpha (PKCα) is a bona fide target of miR-186. Activation of this kinase significantly reversed the miR-186m-repressed angiogenic activity of HDMECs. These findings indicate that downregulation of miR-186 in ECs mediates hypoxia-stimulated NSCLC angiogenesis by upregulating PKCα.

Suppression of endothelial miR-22 mediates non-small cell lung cancer cell-induced angiogenesis

MicroRNAs (miRNAs) expressed in endothelial cells (ECs) are powerful regulators of angiogenesis, which is essential for tumor growth and metastasis. Here, we demonstrated that miR-22 is preferentially and highly expressed in ECs, while its endothelial level is significantly downregulated in human non-small cell lung cancer (NSCLC) tissues when compared to matched nontumor lung tissues. This reduction of endothelial miR-22 is possibly induced by NSCLC cell-secreted interleukin-1β and subsequently activated transcription factor nuclear factor-κB. Endothelial miR-22 functions as a potent angiogenesis inhibitor that inhibits all of the key angiogenic activities of ECs and consequently NSCLC growth through directly targeting sirtuin 1 and fibroblast growth factor receptor 1 in ECs, leading to inactivation of AKT/mammalian target of rapamycin signaling. These findings provide insight into the molecular mechanisms of NSCLC angiogenesis and indicate that endothelial miR-22 represents a potential target for the future antiangiogenic treatment of NSCLC.

Linalool inhibits the angiogenic activity of endothelial cells by downregulating intracellular ATP levels and activating TRPM8

Angiogenesis crucially contributes to various diseases, such as cancer and diabetic retinopathy. Hence, anti-angiogenic therapy is considered as a powerful strategy against these diseases. Previous studies reported that the acyclic monoterpene linalool exhibits anticancer, anti-inflammatory and anti-oxidative activity. However, the effects of linalool on angiogenesis still remain elusive. Therefore, we investigated the action of (3R)-(-)-linalool, a main enantiomer of linalool, on the angiogenic activity of human dermal microvascular endothelial cells (HDMECs) by a panel of angiogenesis assays. Non-cytotoxic doses of linalool significantly inhibited HDMEC proliferation, migration, tube formation and spheroid sprouting. Linalool also suppressed the vascular sprouting from rat aortic rings. In addition, Matrigel plugs containing linalool exhibited a significantly reduced microvessel density 7 days after implantation into BALB/c mice. Mechanistic analyses revealed that linalool promotes the phosphorylation of extracellular signal-regulated kinase (ERK), downregulates the intracellular level of adenosine triphosphate (ATP) and activates the transient receptor potential cation channel subfamily M (melastatin) member (TRPM)8 in HDMECs. Inhibition of ERK signaling, supplementation of ATP and blockade of TRPM8 significantly counteracted linalool-suppressed HDMEC spheroid sprouting. Moreover, ATP supplementation completely reversed linalool-induced ERK phosphorylation. In addition, linalool-induced ERK phosphorylation inhibited the expression of bone morphogenetic protein (BMP)-2 and linalool-induced TRPM8 activation caused the inhibition of β1 integrin/focal adhesion kinase (FAK) signaling. These findings indicate an anti-angiogenic effect of linalool, which is mediated by downregulating intracellular ATP levels and activating TRPM8.

Improvement of islet transplantation by the fusion of islet cells with functional blood vessels

Pancreatic islet transplantation still represents a promising therapeutic strategy for curative treatment of type 1 diabetes mellitus. However, a limited number of organ donors and insufficient vascularization with islet engraftment failure restrict the successful transfer of this approach into clinical practice. To overcome these problems, we herein introduce a novel strategy for the generation of prevascularized islet organoids by the fusion of pancreatic islet cells with functional native microvessels. These insulin-secreting organoids exhibit a significantly higher angiogenic activity compared to freshly isolated islets, cultured islets, and non-prevascularized islet organoids. This is caused by paracrine signaling between the β-cells and the microvessels, mediated by insulin binding to its corresponding receptor on endothelial cells. In vivo, the prevascularized islet organoids are rapidly blood-perfused after transplantation by the interconnection of their autochthonous microvasculature with surrounding blood vessels. As a consequence, a lower number of islet grafts are required to restore normoglycemia in diabetic mice. Thus, prevascularized islet organoids may be used to improve the success rates of clinical islet transplantation.

Protein Kinase CK2 Regulates Nerve/Glial Antigen (NG)2-Mediated Angiogenic Activity of Human Pericytes

Protein kinase CK2 is a crucial regulator of endothelial cell proliferation, migration and sprouting during angiogenesis. However, it is still unknown whether this kinase additionally affects the angiogenic activity of other vessel-associated cells. In this study, we investigated the effect of CK2 inhibition on primary human pericytes. We found that CK2 inhibition reduces the expression of nerve/glial antigen (NG)2, a crucial factor which is involved in angiogenic processes. Reporter gene assays revealed a 114 bp transcriptional active region of the human NG2 promoter, whose activity was decreased after CK2 inhibition. Functional analyses demonstrated that the pharmacological inhibition of CK2 by CX-4945 suppresses pericyte proliferation, migration, spheroid sprouting and the stabilization of endothelial tubes. Moreover, aortic rings of NG2^−/− mice showed a significantly reduced vascular sprouting when compared to rings of NG2^+/+ mice, indicating that NG2 is an important regulator of the angiogenic activity of pericytes. In vivo, implanted Matrigel plugs containing CX-4945-treated pericytes exhibited a lower microvessel density when compared to controls. These findings demonstrate that CK2 regulates the angiogenic activity of pericytes through NG2 gene expression. Hence, the inhibition of CK2 represents a promising anti-angiogenic strategy, because it does not only target endothelial cells, but also vessel-associated pericytes.

Inhibition of erythropoietin-producing hepatoma receptor B4 (EphB4) signalling suppresses the vascularisation and growth of endometriotic lesions

BACKGROUND AND PURPOSE

The development of endometriotic lesions is crucially dependent on the formation of new blood vessels. In the present study, we analysed whether this process is regulated by erythropoietin-producing hepatoma receptor B4 (EphB4) signalling.

EXPERIMENTAL APPROACH

We first assessed the anti-angiogenic action of the EphB4 inhibitor NVP-BHG712 in different in vitro angiogenesis assays. Then, endometriotic lesions were surgically induced in the dorsal skinfold chamber and peritoneal cavity of NVP-BHG712- or vehicle-treated BALB/c mice. This allowed to study the effect of EphB4 inhibition on their vascularisation and growth by means of intravital fluorescence microscopy, high-resolution ultrasound imaging, histology and immunohistochemistry.

KEY RESULTS

Non-cytotoxic doses of NVP-BHG712 suppressed the migration, tube formation and sprouting activity of both human dermal microvascular endothelial cells (HDMEC) and mouse aortic rings. Accordingly, we also detected a lower blood vessel density in NVP-BHG712-treated endometriotic lesions. This was associated with a reduced lesion growth due to a significantly lower number of proliferating stromal cells when compared to vehicle-treated controls.

CONCLUSIONS AND IMPLICATIONS

Inhibition of EphB4 signalling suppresses the vascularisation and growth of endometriotic lesions. Hence, EphB4 represents a promising pharmacological target for the treatment of endometriosis.

[Under the skin-A special manifestation of a systemic granulomatous disease]

Based on the case of a 33-year-old female patient with Löfgren's syndrome and skin changes in the region of a tattoo, this article describes tattoo sarcoidosis as a special manifestation of cutaneous sarcoidosis. Papulonodular changes that are strictly confined to a tattoo are highly suspicious for tattoo sarcoidosis. Interestingly, tattoo sarcoidosis is commonly associated with the involvement of other organs.

Calligonum comosum (Escanbil) extract exerts anti-angiogenic, anti-proliferative and anti-inflammatory effects on endometriotic lesions

ETHNOPHARMACOLOGICAL RELEVANCE

Calligonum comosum is a desert plant that is applied in traditional folkloric medicine for the treatment of abnormally heavy or prolonged menstruation and menstrual cramps. Moreover, it has been suggested for the treatment of infertility-causing conditions. Its bioactive chemical constituents inhibit multiple processes, such as angiogenesis, inflammation and invasive tissue growth, which may be beneficial in the therapy of endometriosis.

AIM OF THE STUDY

We investigated the effects of Calligonum comosum on the development of endometriotic lesions.

MATERIALS AND METHODS

We evaluated the anti-angiogenic activity of Calligonum comosum ethyl acetate fraction (CCEAF) in different in vitro angiogenesis assays. Moreover, we surgically induced endometriotic lesions in BALB/c mice, which received 50 mg/kg Calligonum comosum total extract (CCTE) or vehicle (control) over 4 weeks. The growth, cyst formation, vascularization and immune cell infiltration of the lesions were assessed with high-resolution ultrasound imaging, caliper measurements, histology and immunohistochemistry.

RESULTS

CCEAF doses of up to 10 μg/mL did not impair the viability of human dermal microvascular endothelial cells (HDMEC), but dose-dependently suppressed their migration, tube formation and sprouting, indicating a substantial anti-angiogenic effect of CCEAF. Furthermore, CCTE significantly inhibited the growth and cyst formation of developing murine endometriotic lesions when compared to vehicle-treated controls. This was associated with a reduced vascularization, cell proliferation and immune cell infiltration.

CONCLUSIONS

Our findings show that Calligonum comosum targets multiple, fundamental processes in the pathogenesis of endometriosis, which may be beneficial for the treatment of this common gynecological disorder.

miR-370 inhibits the angiogenic activity of endothelial cells by targeting smoothened (SMO) and bone morphogenetic protein (BMP)-2

MicroRNAs (miRNAs) crucially modulate fundamental biologic processes such as angiogenesis. In the present study, we focused on the molecular function of miRNA-370-3p (miR-370) in regulating the angiogenic activity of endothelial cells (ECs). Transfection with miR-370 mimic (miR-370m) significantly inhibited the sprouting of human dermal microvascular EC (HDMEC) and HUVEC spheroids and mouse aortic rings, whereas miR-370 inhibitor (miR-370i) promoted sprout formation. Additional in vitro assays demonstrated the pleiotropic inhibitory effects of miR-370m on HDMEC proliferation, migration, and tube formation. Moreover, Matrigel plugs containing miR-370m-transfected HDMECs exhibited a reduced microvessel density after implantation into CD1 nude mice when compared with controls. In contrast, miR-370i exerted proangiogenic effects. Mechanistic analyses revealed that miR-370 directly targets smoothened (SMO) and down-regulates bone morphogenetic protein (BMP)-2 expression in HDMECs. Accordingly, inhibition of SMO by cyclopamine reversed miR-370i-induced HDMEC proliferation and migration. In addition, BMP-2 treatment counteracted miR-370m-suppressed tube formation of HDMECs, whereas blockade of BMP-2 with neutralizing antibody significantly inhibited miR-370i-induced tube formation. Taken together, these novel findings indicate that miR-370 is a potent inhibitor of angiogenesis, which directly targets SMO and BMP-2.-Gu, Y., Becker, V., Zhao, Y., Menger, M. D., Laschke, M. W. miR-370 inhibits the angiogenic activity of endothelial cells by targeting smoothened (SMO) and bone morphogenetic protein (BMP)-2.

Determination of the electron-lattice coupling strength of copper with ultrafast MeV electron diffraction

Electron-lattice coupling strength governs the energy transfer between electrons and the lattice and is important for understanding the material behavior under highly non-equilibrium conditions. Here we report the results of employing time-resolved electron diffraction at MeV energies to directly study the electron-lattice coupling strength in 40-nm-thick polycrystalline copper excited by femtosecond optical lasers. The temporal evolution of lattice temperature at various pump fluence conditions were obtained from the measurements of the Debye-Waller decay of multiple diffraction peaks. We observed the temperature dependence of the electron-lattice relaxation time which is a result of the temperature dependence of electron heat capacity. Comparison with two-temperature model simulations reveals an electron-lattice coupling strength of (0.9 ± 0.1) × 10¹⁷ W/m³/K for copper.

Phosphorus fractionation in sediments of tropical semiarid reservoirs

The reduction of external loads of phosphorus (P) is the main action to control eutrophication in lakes. However, the elimination of these sources is not always sufficient for lakes' recovery, because the P accumulated in the sediment can be released for decades after it has accumulated. Thus, to restore a lake, it is also necessary to reduce its internal P loading. For this, it is essential to know the composition of P in the sediment to evaluate the potential P availability. In this study, the forms of P in the sediment of two reservoirs in a semiarid tropical region were investigated. The forms of P were determined by fractionation, sorting out the forms in loosely sorbed P (P-Water), reductant-soluble P (P-BD), metal oxide-bound P (P-NaOH), P bound to organic matter (P-Humic), calcium-bound P (P-HCl) and residual P (P-residual). The sediment was collected in September 2016 and sliced in situ. The total amount of P forms in the sediment varied from 5mgkg^-1 to 349mgkg^-1 in the Gargalheiras Reservoir and from 12mgkg^-1 to 371mgkg^-1 in the Cruzeta Reservoir. Despite some variation in amounts at different depths, the general range of fractions in Gargalheiras and Cruzeta was: P-BD>P-NaOH>P-HCl>P-water>P-Residual>P-Humic. In both reservoirs, the predominant form was BD, followed by NaOH and HCl. The first two forms are available and released easily, making them bioavailable for eutrophication processes and thus phytoplankton growth.

Esophageal bougination: a novel ex vivo endoscopic training model correlated with clinical data

BACKGROUND

Esophageal bougination is a worldwide standard endoscopic procedure. Clinical methods and recommendations are based on clinical experiences only. Mechanical properties have never been described. Aim of the study was to establish a realistic ex vivo training model. Therefore, detailed assessment of relevant mechanical features of esophageal bougination should be evaluated ex vivo and in patient setting and correlated against.

PATIENTS AND METHODS

A three-step concept was used to evaluate mechanical properties at stenosis level. First, insertion forces were evaluated in an ex vivo linear single stenosis model during steady mechanical insertion. Second, adding friction and properties of the pharynx and upper esophagus, the model was integrated in an artificial endoscopic training model (ELITE training model). Third, in vivo measurements were taken to correlate ex vivo data with parameters of a realistic patient setting.

RESULTS

With the presented setup, we were able to assess insertion force and pressure levels in an artificial stricture using different sizes of commercially available standard bougies. In all models, there was a relevant increase in insertion force with higher stricture pressure levels. Insertion force levels in the ELITE model show higher levels compared to the linear stenosis model. Having regard to the maximum forces in patients, there is also a constant increase in mean insertion force according to higher bougie sizes, but lower forces were measured as in the ELITE model.

DISCUSSION

The applied models are suitable to appraise mechanical properties of esophageal bougination in an ex vivo model and patient setting. Forces could be constituted reliable, significant increase was documented according to stenosis level and results were comparable to patient data. This was comparable to patient data. Further clinical evaluation in different kinds of stenosis is necessary.

High-resolution manometry in patients with eosinophilic esophagitis under topical steroid therapy-a prospective observational study (HIMEOS-study)

BACKGROUND

In eosinophilic esophagitis (EoE), dysphagia, which might reflect esophageal dysmotility, is the most common symptom. High-resolution manometry (HRM) has become widely accepted for evaluating esophageal motility disorders, but to date has been sparsely examined in EoE patients, particularly under therapy. The aim of this study was to evaluate HRM in symptomatic EoE-patients under topical steroid treatment.

METHODS

In this prospective observational study, symptomatic EoE patients received HRM-examinations before and after 8 weeks of topical steroid treatment with budesonide. All HRM-abnormalities were assessed and interpreted according to the Chicago classification. The primary endpoint was the influence of topical steroid treatment on the intrabolus pressure (IBP). Clinical symptoms, endoscopic findings and histological esophageal eosinophilic load were also reported.

KEY RESULTS

Twenty symptomatic EoE patients were included. Overall success of budesonide therapy was 85% regarding complete histologic remission and 80% regarding complete clinical remission. High-resolution manometry showed abnormal esophageal motility in 35% of patients at baseline, which was resolved after therapy in 86% of these patients. Most frequent HRM-findings were early pan-esophageal pressurizations and weak persitalsis. There was no significant reduction of the IBP under therapy (before: 12.5 ± 4.9 mmHg, after: 10.9 ± 2.9 mmHg; p = 0.119).

CONCLUSIONS & INFERENCES

Although dysphagia is the leading symptom of EoE, HRM is able to identify esophageal motility disorders in only some EoE patients. Observed motility disorders resolve after successful treatment in almost all of these patients. Intrabolus pressure does not seem an optimal parameter for the monitoring of successful treatment response in EoE patients.

Occurrence and origin of methane in groundwater in Alberta (Canada): Gas geochemical and isotopic approaches

To assess potential future impacts on shallow aquifers by leakage of natural gas from unconventional energy resource development it is essential to establish a reliable baseline. Occurrence of methane in shallow groundwater in Alberta between 2006 and 2014 was assessed and was ubiquitous in 186 sampled monitoring wells. Free and dissolved gas sampling and measurement approaches yielded comparable results with low methane concentrations in shallow groundwater, but in 28 samples from 21 wells methane exceeded 10mg/L in dissolved gas and 300,000 ppmv in free gas. Methane concentrations in free and dissolved gas samples were found to increase with well depth and were especially elevated in groundwater obtained from aquifers containing coal seams and shale units. Carbon isotope ratios of methane averaged -69.7 ± 11.1‰ (n=63) in free gas and -65.6 ± 8.9‰ (n=26) in dissolved gas. δ(13)C values were not found to vary with well depth or lithology indicating that methane in Alberta groundwater was derived from a similar source. The low δ(13)C values in concert with average δ(2)HCH4 values of -289 ± 44‰ (n=45) suggest that most methane was of biogenic origin predominantly generated via CO2 reduction. This interpretation is confirmed by dryness parameters typically >500 due to only small amounts of ethane and a lack of propane in most samples. Comparison with mud gas profile carbon isotope data revealed that methane in the investigated shallow groundwater in Alberta is isotopically similar to hydrocarbon gases found in 100-250 meter depths in the WCSB and is currently not sourced from thermogenic hydrocarbon occurrences in deeper portions of the basin. The chemical and isotopic data for methane gas samples obtained from Alberta groundwater provide an excellent baseline against which potential future impact of deeper stray gases on shallow aquifers can be assessed.

Stable carbon isotope fractionation data between H(2)CO(3)(*) and CO(2)(g) extended to 120 °C

RATIONALE

Literature data on experimentally derived equilibrium stable carbon isotope fractionation (10(3) lnα(13) C) between H2 CO3 (*) (H2 CO3  + CO2(aq) ) and gaseous CO2 (CO2(g) ) are so far only available up to 60 °C and were typically determined at or near atmospheric pressures. Here we experimentally expand this dataset to temperature and pressure conditions close to the supercritical state for CO2 . The objective is to improve the applicability of stable carbon isotopes as a tracer in environments where such conditions prevail.

METHODS

Eighteen stable carbon isotope laboratory experiments were conducted in a steel vessel. Deionised water that was acidified with hydrochloric acid (HCl, 1 N) to a pH of 2.4 was equilibrated with CO2(g) at pressures (pCO2 ) of 55 bar for durations between 2 and 188 h. The experiments were conducted at 20, 60, 80, 100 and 120 °C. H2 CO3 (*) and CO2(g) were sampled separately and their carbon isotope ratios were determined by isotope ratio mass spectrometry.

RESULTS

At 20 °C, average 10(3) lnα(13) CH2CO3 * -CO2(g) values of -1.0 ± 0.1 ‰ were observed with a preference for (12) C in H2 CO3 (*) consistent with previous research. At elevated temperatures of 120 °C, 10(3) lnα(13) CH2CO3 * -CO2(g) values decreased to an average value of -0.7 ± 0.1 ‰. The resulting temperature dependence for carbon isotope fractionation between H2 CO3 (*) and CO2(g) was 10(3) lnα(13) CH2CO3 * -CO2(g)  = (0.0025 ± 0.0004) T(°C) - (1.0 ± 0.03) ‰. Carbon isotope equilibrium between H2 CO3 (*) and CO2(g) was reached within reaction times of 18 h and mostly within 5 h or less.

CONCLUSIONS

10(3) lnα(13) CH2CO3 * -CO2(g) data are now available for temperatures up to 120 °C and for pressures of up to 55 bar. The results suggest that higher pCO2 levels possibly shorten carbon isotope equilibration times. These data are critically important for using δ(13) C values as tracers, for instance at geological CO2 sequestration sites and corresponding natural analogues.

Long-term follow-up in patients with indeterminate Barrett esophagus

BACKGROUND

Barrett esophagus (BE) is a major risk factor for adenocarcinoma of the distal esophagus. Reliable detection of BE during upper endoscopy is therefore mandatory. According to most guidelines, diagnosis of BE requires both endoscopy and histology for confirmation. However, since adenocarcinomas were also described in patients with indeterminate BE, i.e. endoscopic visible columnar metaplasia but no histological confirmation of goblet cells or vice versa, debate has risen on the risk of malignancy and the need for endoscopic surveillance in such patients.

PATIENTS AND METHODS

The study was aimed to assess long-term follow-up data on 209 patients with indeterminate BE (on histopathology or endoscopy) initially examined between 1999 and 2000. Patients or referring physicians were contacted concerning the most recent endoscopic and histopathological results.

RESULTS

Follow-up data could be assessed in 149/209 patients (65.1%) after a mean follow-up period of 9.4 years (SD ±2.4 years). Neoplasia was not reported for any patient. The previous endoscopic-histopathological diagnoses could be confirmed in 3 patients only. In the group with endoscopic diagnosis of BE but no histopathological confirmation, BE was described histopathologically in 1 patient during follow-up.

CONCLUSION

Persistence of indeterminate BE is poor during long-term follow up. The risk of cancer appears to be negligible. Hence, surveillance of these patients appears equivocal.

Classification of probe-based confocal laser endomicroscopy findings in pancreaticobiliary strictures

BACKGROUND AND STUDY AIMS

The accurate diagnosis of indeterminate pancreaticobiliary strictures presents a clinical dilemma. Probe-based confocal laser endomicroscopy (pCLE) offers real-time in vivo microscopic tissue examination that may increase sensitivity for the detection of malignancy. the objective of this study was to develop and validate a standard descriptive classification of pcle in the pancreaticobiliary system.

PATIENTS AND METHODS

A total of 102 patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) with pCLE to assess indeterminate pancreaticobiliary strictures were enrolled in a multicenter registry; 89 of these patients were evaluable. Information and data on the following were collected prospectively: clinical, ERCP, tissue sampling, pCLE, and follow-up. A uniform classification of pCLE findings ("Miami Classification") was developed, consisting of a set of image interpretation criteria. Thereafter, these criteria were tested through blinded consensus review of 112 randomized pCLE videos from 47 patients, and inter-observer variability was assessed in 42 patients .

RESULTS

A consensus definition of the specific criteria of biliary and pancreatic pCLE findings for indeterminate strictures was developed. Single-image interpretation criteria did not have a high enough sensitivity for predicting malignancy. However, combining two or more criteria significantly increased the sensitivity and predictive values. The characteristics most suggestive of malignancy included the following: thick white bands (>20 µm), or thick dark bands (>40 µm), or dark clumps or epithelial structures. These provided sensitivity, specificity, positive predictive value, and negative predictive value of 97%, 33%, 80%, and 80% compared with 48%, 100%, 100%, and 41% for standard tissue sampling methods. Inter-observer variability was moderate for most criteria.

CONCLUSION

The Miami Classification enables a structured, uniform, and reproducible description of pancreaticobiliary pCLE. Combining individual characteristics improves the sensitivity for the detection of malignancy.

Predictive mathematical models of cancer signalling pathways

Complex intracellular signalling networks integrate extracellular signals and convert them into cellular responses. In cancer cells, the tightly regulated and fine-tuned dynamics of information processing in signalling networks is altered, leading to uncontrolled cell proliferation, survival and migration. Systems biology combines mathematical modelling with comprehensive, quantitative, time-resolved data and is most advanced in addressing dynamic properties of intracellular signalling networks. Here, we introduce different modelling approaches and their application to medical systems biology, focusing on the identifiability of parameters in ordinary differential equation models and their importance in network modelling to predict cellular decisions. Two related examples are given, which include processing of ligand-encoded information and dual feedback regulation in erythropoietin (Epo) receptor signalling. Finally, we review the current understanding of how systems biology could foster the development of new treatment strategies in the context of lung cancer and anaemia.

Multimodal endoscopic therapy for multifocal intraepithelial neoplasia and superficial esophageal squamous cell carcinoma - a case series

Local endoscopic procedures are increasingly used and accepted treatments for unifocal superficial esophageal squamous cell carcinoma (SESCC). In multifocal SESCC, esophagectomy with or without chemoradiotherapy is often regarded as standard therapy. However, a combination of local endoscopic resection and new techniques such as radiofrequency ablation may play an increasing role in the treatment of selected patients with multifocal SESCC. The aim of this series was to evaluate the feasibility of a multimodal endoscopic approach. We report a case series of six consecutive patients from a European tertiary center who underwent endoscopic treatment for multifocal SESCC. The treatment comprised endoscopic mucosal resection using the cap technique or endoscopic submucosal dissection, in combination with radiofrequency ablation. The main outcome measure was complete tumor eradication after therapy and during the follow-up period. Using such an approach, complete eradication of cancer was achieved in all patients during follow-up. No major adverse events occurred. In conclusion, in selected patients with multifocal or residual SESCC, local resection techniques in combination with radiofrequency ablation may be safe and potentially curative alternative treatments.

Identifiability and observability analysis for experimental design in nonlinear dynamical models

Dynamical models of cellular processes promise to yield new insights into the underlying systems and their biological interpretation. The processes are usually nonlinear, high dimensional, and time-resolved experimental data of the processes are sparse. Therefore, parameter estimation faces the challenges of structural and practical nonidentifiability. Nonidentifiability of parameters induces nonobservability of trajectories, reducing the predictive power of the model. We will discuss a generic approach for nonlinear models that allows for identifiability and observability analysis by means of a realistic example from systems biology. The results will be utilized to design new experiments that enhance model predictiveness, illustrating the iterative cycle between modeling and experimentation in systems biology.

Probe-based confocal laser endomicroscopy compared with standard four-quadrant biopsy for evaluation of neoplasia in Barrett's esophagus

BACKGROUND AND STUDY AIMS

Surveillance of Barrett's esophagus includes endoscopic inspection with biopsy of suspicious lesions followed by four-quadrant biopsy of the remaining mucosa. We assessed the ability of probe-based confocal laser endomicroscopy (pCLE) to replace biopsy in the endoscopic evaluation of patients with Barrett's esophagus in a prospective and controlled setting.

PATIENTS AND METHODS

A total of 68 patients who were referred for endoscopic assessment of Barrett's esophagus were included across three centers. pCLE recordings were interpreted live during the examination as well as in a blinded manner at least 3 months after endoscopy. pCLE diagnosis of neoplasia based on pre-defined criteria was compared with histopathology from suspicious as well as four-quadrant biopsies.

RESULTS

A total of 670 pairs of biopsies and pCLE video sequences were available for analysis, with neoplasia (high-grade dysplasia or cancer) being histologically diagnosed in 8.3 %. Specificity and negative predictive value of pCLE in excluding neoplasia was 0.97 (90 %CI 0.95 - 0.98) and 0.93 (0.91 - 0.95) for the blinded evaluation, and 0.95 (0.90 - 0.98) and 0.92 (0.90 - 0.94) for the on-site assessment. Positive predictive values (PPVs) and sensitivity were rather poor for both settings (46 %/28 % [blinded] and 18 %/12 % [on-site], respectively).

CONCLUSIONS

pCLE can be regarded as non-inferior to endoscopic biopsy in excluding neoplasia of Barrett's esophagus mucosa. However, due to its low PPV and sensitivity, pCLE may currently not replace standard biopsy techniques for the diagnosis of Barrett's esophagus and associated neoplasia. Further technical development of pCLE and a better understanding of its role in relation to other imaging technologies are necessary.

Natural orifice transluminal endoscopic surgery: cardiopulmonary safety of transesophageal mediastinoscopy

BACKGROUND AND STUDY AIMS

Physiological reactions during natural orifice transluminal endoscopic surgery (NOTES) mediastinoscopy may lead to cardiorespiratory depression. The aim of the current study was to assess cardiopulmonary changes during transesophageal mediastinoscopy in an acute porcine model.

METHODS

Transesophageal mediastinoscopy was performed under general anesthesia in eight female pigs with a bodyweight of 39 +/- 6 kg. Mediastinal access was achieved via a submucosal tunnel. The cardiac index and global end-diastolic volume index (reflecting preload) were measured every 3 minutes by transpulmonary thermodilution. The following parameters were also recorded: mediastinal pressure, heart rate, mean arterial pressure, systemic vascular resistance index (SVRI; reflecting afterload), peak inspiratory pressure, pH, pCO (2), and pO (2).

RESULTS

In three animals, small tears in the parietal pleura resulted in tension pneumothoraces. The associated cardioplumonary deterioration was fatal in one pig. The other two pigs recovered after decompression with a chest tube. In the remaining five animals there were only mild hemodynamic and respiratory changes during mediastinoscopy. There was a significant ( P = 0.005) but minor transient fall in cardiac index, which correlated with a small rise in SVRI (r = - 0.857, P < 0.001). In the pigs with uncomplicated mediastinoscopy, on-demand insufflation via the endoscope resulted in median mediastinal pressures of 4.5 mm Hg (range 2.3 - 10.2 mm Hg). Overall, mediastinal and thoracic structures could be identified without difficulty via the transesophageal approach.

CONCLUSIONS

NOTES mediastinoscopy carries a substantial risk of inadvertent development of a pneumothorax. Otherwise, it leads to negligible hemodynamic and pulmonary changes. In conclusion, close monitoring for the presence of a pneumothorax during NOTES mediastinoscopy appears to be mandatory.

Wetting of Sapphire by a Supercooled Silicon Droplet

A small piece of silicon was melted in vacuum in a high precision spherical depression of a heated (0001) oriented sapphire substrate. The droplet was observed from above by use of a microscope equipped with a CMOS video camera. Above the melting point (1687 K) it exhibited small but rapid breathing mode fluctuations. The frequency of these fluctuations could be slowed down by supercooling the droplet to about 80 K below the melting temperature, allowing a detailed study of the effect. An unusual contour structure with a threefold rotation symmetry was observed, when the droplet had spread to its maximum contour diameter. This pattern can be related to the ditrigonal-scalenohedral 3¯m symmetry of the sapphire crystal.

Infected necrosis in severe pancreatitis--combined nonsurgical multi-drainage with directed transabdominal high-volume lavage in critically ill patients

BACKGROUND

Infection of pancreatic necrosis is a life-threatening complication during the course of acute pancreatitis. In critically ill patients, surgical or extended endoscopic interventions are associated with high morbidity and mortality. Minimally invasive procedures on the other hand are often insufficient in patients suffering from large necrotic areas containing solid or purulent material. We present a strategy combining percutaneous and transgastric drainage with continuous high-volume lavage for treatment of extended necroses and liquid collections in a series of patients with severe acute pancreatitis.

PATIENTS AND METHODS

Seven consecutive patients with severe acute pancreatitis and large confluent infected pancreatic necrosis were enrolled. In all cases, the first therapeutic procedure was placement of a CT-guided drainage catheter into the fluid collection surrounding peripancreatic necrosis. Thereafter, a second endosonographically guided drainage was inserted via the gastric or the duodenal wall. After communication between the separate drains had been proven, an external to internal directed high-volume lavage with a daily volume of 500 ml up to 2,000 ml was started.

RESULTS

In all patients, pancreatic necrosis/liquid collections could be resolved completely by the presented regime. No patient died in the course of our study. After initiation of the directed high-volume lavage, there was a significant clinical improvement in all patients. Double drainage was performed for a median of 101 days, high-volume lavage for a median of 41 days. Several endoscopic interventions for stent replacement were required (median 8). Complications such as bleeding or perforation could be managed endoscopically, and no subsequent surgical therapy was necessary. All patients could be dismissed from the hospital after a median duration of 78 days.

CONCLUSION

This approach of combined percutaneous/endoscopic drainage with high-volume lavage shows promising results in critically ill patients with extended infected pancreatic necrosis and high risk of surgical intervention. Neither surgical nor endoscopic necrosectomy was necessary in any of our patients.

Miniprobe confocal laser microscopy for the detection of invisible neoplasia in patients with Barrett's oesophagus

OBJECTIVE

The biggest challenge in endoscopic surveillance of Barrett's oesophagus is better detection of neoplasia in mucosa of normal macroscopic appearance. We evaluated in vivo miniprobe confocal laser microscopy (CLM) for the detection of invisible Barrett's neoplasia.

DESIGN

Prospective two-centre trial in two phases: phase I to establish criteria of Barrett's neoplasia and phase II to test these criteria.

PATIENTS AND INTERVENTION

296 biopsy sites in 38 consecutive patients with Barrett's oesophagus (mean age 62.1 years, 89.5% men, median length of the Barrett's oesophagus, 3 cm) were examined with standard high-resolution endoscopy and by miniprobe CLM, with precise matching of CLM recordings to biopsy sites. CLM image criteria for normal versus neoplastic Barrett's oesophagus were established from 95 biopsies of 15 patients (phase I); these criteria were then prospectively tested on 201 biopsies from the remaining patients without visible focal changes (phase II). All 201 CLM video recordings from phase II cases were randomised and blindly evaluated by two gastroenterologists.

MAIN OUTCOME MEASURE

The primary endpoints were accuracy values in diagnosing HGIN or early carcinoma (EC) on a per-biopsy basis. Secondary endpoints included inter-observer agreement.

RESULTS

All initially defined miniprobe CLM criteria (phase I) were significantly more frequently detected in HGIN/EC sites compared with sites with no or low grade neoplasia (phase II). In a per-biopsy analysis, sensitivity and specificity for two independent investigators were 75.0% and 88.8%, and 75.0% and 91.0%, respectively, translating at best into a positive predictive value of 44.4% and a negative predictive value of 98.8%. Inter-observer agreement was good (kappa 0.6).

CONCLUSION

Miniprobe CLM showed a high negative predictive value for the diagnosis of endoscopically invisible neoplasia in Barrett's oesophagus; sensitivity, however, has still to be improved.

Confocal laser scanning fluorescence microscopy for in vivo determination of microvessel density in Barrett's esophagus

BACKGROUND AND STUDY AIMS

Angiogenesis has been reported to be an essential step in the progression of cancers arising from Barrett's esophagus. Confocal laser scanning microscopy (CLM) has the potential to perform in vivo microscopy to detect angiogenesis and determine microvessel density (MVD). We aimed therefore to use this new promising imaging tool for the evaluation of MVD in Barrett's esophagus and associated neoplasia.

PATIENTS AND METHODS

We enrolled 20 patients with Barrett's esophagus. CLM sequences were recorded from pre-marked areas using argon beamer coagulation spots after intravenous application of fluorescein. Sequences had to be recorded within the first 8 minutes of injection. Biopsies were taken from the same areas for standard histopathology. All CLM sequences were put into a random order and analyzed by a single investigator who was blinded to any clinical or histopathological data. Five still images per sequence were analyzed for MVD using a specially designed software algorithm. The primary endpoint was determination of vessel diameter and MVD in relation to neoplastic or non-neoplastic Barrett's esophagus.

RESULTS

We evaluated 750 still CLM images from 150 sequences/biopsy sites. Histopathology revealed 69 biopsies as non-neoplastic Barrett's esophagus (46.0 %), 11 as neoplastic Barrett's esophagus (7.3 %), 64 as cardiac mucosa (42.7 %), and six as squamous mucosa (4.0 %). Mean vessel diameter as determined by CLM was similar in all four groups (P = 0.2). However, MVD was significantly higher in CLM sequences of neoplastic Barrett's esophagus compared with benign conditions (neoplastic Barrett's esophagus 23.6 %; Barrett's esophagus 14.2 %; cardiac mucosa 15.8 %; squamous epithelium 20.6 %; neoplastic Barrett's esophagus vs. Barrett's esophagus P < 0.001, T-test).

CONCLUSION

Fibered fluorescein-guided CLM helps to detect angiogenesis in malignant and non-malignant Barrett's esophagus in vivo. These data might help to improve the diagnostic yield of detecting Barrett's neoplasia but also to facilitate monitoring of antiangiogenetic therapy.

Coefficient of tangential restitution for viscoelastic spheres

The collision of frictional granular particles may be described by an interaction force whose normal component is that of viscoelastic spheres while the tangential part is described by the model by Cundall and Strack (Géotechnique 29, 47 (1979)) being the most popular tangential collision model in Molecular Dynamics simulations. Albeit being a rather complicated model, governed by 5 phenomenological parameters and 2 independent initial conditions, we find that it is described by 3 independent parameters only. Surprisingly, in a wide range of parameters the corresponding coefficient of tangential restitution, epsilont, is well described by the simple Coulomb law with a cut-off at epsilont = 0. A more complex behavior of the coefficient of restitution as a function on the normal and tangential components of the impact velocity, gn and gt, including negative values of epsilont, is found only for very small ratio gt/gn. For the analysis presented here we neglect dissipation of the interaction in normal direction.