An Improved In Vivo Methodology to Visualise Tumour Induced Changes in Vasculature Using the Chick Chorionic Allantoic Membrane Assay

Background/Aim: Decreasing the vascularity of a tumour has proven to be an effective strategy to suppress tumour growth and metastasis. Anti-angiogenic therapies have revolutionized the treatment of advanced-stage cancers, however there is still demand for further improvement. This necessitates new experimental models that will allow researchers to reliably study aspects of angiogenesis. The aim of this study was to demonstrate an in vivo technique in which the highly vascular and accessible chorioallantoic membrane (CAM) of the chick embryo is used to study tumour-induced changes in the macro and microvessels. Materials and Methods: Two cancer cell lines (human melanoma (C8161) and human prostate cancer (PC3)) were selected as model cells. Human dermal fibroblasts were used as a control. One million cells were labelled with green fluorescent protein and implanted on the CAM of the chick embryo at embryonic development day (EDD) 7 and angiogenesis was evaluated at EDDs 10, 12 and 14. A fluorescently-tagged lectin (lens culinaris agglutinin (LCA)) was injected intravenously into the chick embryo to label endothelial cells. The LCA is known to label the luminal surface of endothelial cells, or dextrans, in the CAM vasculature. Macrovessels were imaged by a hand-held digital microscope and images were processed for quantification. Microvessels were evaluated by confocal microscopy. Tumour invasion was assessed by histological and optical sectioning. Results: Tumour cells (C8161 and PC3) produced quantifiable increases in the total area covered by blood vessels, compared to fibroblasts when assessed by digital microscopy. Tumour invasion could be demonstrated by both histological and optical sectioning. The most significant changes in tumour vasculature observed were in the microvascular structures adjacent to the tumour cells, which showed an increase in the endothelial cell coverage. Additionally, tumour intravasation and tumour thrombus formation could be detected in the areas adjacent to tumour cells. The fragility of tumour blood vessels could be demonstrated when tumour cells seeded on a synthetic scaffold were grown on CAM. Conclusion: We report on a modification to a well-studied CAM in vivo assay, which can be effectively used to study tumour induced changes in macro and microvasculature

Generation of inverted heliospheric magnetic flux by coronal loop opening and slow solar wind release

In situ spacecraft observations provide much-needed constraints on theories of solar wind formation and release, particularly the highly variable slow solar wind, which dominates near-Earth space. Previous studies have shown an association between local inversions in the heliospheric magnetic field (HMF) and solar wind released from the vicinity of magnetically closed coronal structures. We here show that in situ properties of inverted HMF are consistent with the same hot coronal source regions as the slow solar wind. We propose that inverted HMF is produced by solar wind speed shear, which results from interchange reconnection between a coronal loop and open flux tube, and introduces a pattern of fast–slow–fast wind along a given HMF flux tube. This same loop-opening process is thought to be central to slow solar wind formation. The upcoming Parker Solar Probe and Solar Orbiter missions provide a unique opportunity to directly observe these processes and thus determine the origin of the slow solar wind

Overcoming scarring in the urethra: Challenges for tissue engineering.

Urethral stricture disease is increasingly common occurring in about 1% of males over the age of 55. The stricture tissue is rich in myofibroblasts and multi-nucleated giant cells which are thought to be related to stricture formation and collagen synthesis. An increase in collagen is associated with the loss of the normal vasculature of the normal urethra. The actual incidence differs based on worldwide populations, geography, and income. The stricture aetiology, location, length and patient's age and comorbidity are important in deciding the course of treatment. In this review we aim to summarise the existing knowledge of the aetiology of urethral strictures, review current treatment regimens, and present the challenges of using tissue-engineered buccal mucosa (TEBM) to repair scarring of the urethra. In asking this question we are also mindful that recurrent fibrosis occurs in other tissues-how can we learn from these other pathologies

Are Amphipod invaders a threat to the regional biodiversity? Conservation prospects for the Loire River

The impact of invasions on local biodiversity is well established, but their impact on regional biodiversity has so far been only sketchily documented. To address this question, we studied the impact at various observation scales (ranging from the microhabitat to the whole catchment) of successive arrivals of non-native amphipods on the amphipod assemblage of the Loire River basin in France. Amphipod assemblages were studied at 225 sites covering the whole Loire catchment. Non-native species were dominant at all sites in the main channel of the Loire River, but native species were still present at most of the sites. We found that the invaders have failed to colonize most of tributaries of the Loire River. At the regional scale, we found that since the invaders first arrived 25 years ago, the global amphipod diversity has increased by 33% (from 8 to 12 species) due to the arrival of non-native species. We discuss the possibility that the lack of any loss of biodiversity may be directly linked to the presence of refuges at the microhabitat scale in the Loire channel and in the tributaries, which invasive species have been unable to colonize. The restoration of river quality could increase the number of refuges for native species, thus reducing the impact of invader

A case report and genetic characterization of a massive acinic cell carcinoma of the parotid with delayed distant metastases.

We describe the presentation, management, and clinical outcome of a massive acinic cell carcinoma of the parotid gland. The primary tumor and blood underwent exome sequencing which revealed deletions in CDKN2A as well as PPP1R13B, which induces p53. A damaging nonsynonymous mutation was noted in EP300, a histone acetylase which plays a role in cellular proliferation. This study provides the first insights into the genetic underpinnings of this cancer. Future large-scale efforts will be necessary to define the mutational landscape of salivary gland malignancies to identify therapeutic targets and biomarkers of treatment failure

Oxygen mapping of melanoma spheroids using small molecule platinum probe and phosphorescence lifetime imaging microscopy

Solid tumours display varied oxygen levels and this characteristic can be exploited to develop new diagnostic tools to determine and exploit these variations. Oxygen is an efficient quencher of emission of many phosphorescent compounds, thus oxygen concentration could in many cases be derived directly from relative emission intensity and lifetime. In this study, we extend our previous work on phosphorescent, low molecular weight platinum(II) complex as an oxygen sensing probe to study the variation in oxygen concentration in a viable multicellular 3D human tumour model. The data shows one of the first examples of non-invasive, real-time oxygen mapping across a melanoma tumour spheroid using one-photon phosphorescence lifetime imaging microscopy (PLIM) and a small molecule oxygen sensitive probe. These measurements were quantitative and enabled real time oxygen mapping with high spatial resolution. This combination presents as a valuable tool for optical detection of both physiological and pathological oxygen levels in a live tissue mass and we suggest has the potential for broader clinical application

Triethyl orthoformate covalently cross-linked chitosan-(poly vinyl) alcohol based biodegradable scaffolds with heparin-binding ability for promoting neovascularisation

There is a need to develop pro-angiogenic biomaterials to promote wound healing and to assist in regenerative medicine. To this end, various growth factors have been exploited which have the potential to promote angiogenesis. However, these are generally expensive and labile which limits their effectiveness. An alternative approach is to immobilize heparin onto biocompatible degradable hydrogels. The heparin in turn will then bind endogenous proangiogenic growth factors to induce formation of new blood vessels.In this study, we continue our development of hydrogels for wound healing purposes by exploring covalently cross-linking chitosan and polyvinyl alcohol hydrogels using triethyl orthoformate. Two concentrations of triethyl orthoformate (4 and 16%) were compared for their effects on the structure of hydrogels - their swelling, pore size, and rate of degradation and for their ability to support the growth of cells and for their heparin-binding capacity and their effects on angiogenesis in a chick chorioallantoic membrane assay.Hydrogels formed with 4 or 16% both triethyl orthoformate cross-linker were equally cyto-compatible. Hydrogels formed with 4% triethyl orthoformate absorbed slightly more water than those made with 16% triethyl orthoformate and broke down slightly faster than non-cross-linked hydrogels. When soaked in heparin the hydrogel formed with 16% triethyl orthoformate showed more blood vessel formation in the CAM assay than that formed with 4% triethyl orthoformate

Repurposing Albendazole: new potential as a chemotherapeutic agent with preferential activity against HPV-negative head and neck squamous cell cancer.

Albendazole is an anti-helminthic drug that has been shown to exhibit anti-cancer properties, however its activity in head and neck squamous cell cancer (HNSCC) was unknown. Using a series of in vitro assays, we assessed the ability of albendazole to inhibit proliferation in 20 HNSCC cell lines across a range of albendazole doses (1 nM-10 μM). Cell lines that responded to treatment were further examined for cell death, inhibition of migration and cell cycle arrest. Thirteen of fourteen human papillomavirus-negative HNSCC cell lines responded to albendazole, with an average IC50 of 152 nM. In contrast, only 3 of 6 human papillomavirus-positive HNSCC cell lines responded. Albendazole treatment resulted in apoptosis, inhibition of cell migration, cell cycle arrest in the G2/M phase and altered tubulin distribution. Normal control cells were not measurably affected by any dose tested. This study indicates that albendazole acts to inhibit the proliferation of human papillomavirus-negative HNSCC cell lines and thus warrants further study as a potential chemotherapeutic agent for patients suffering from head and neck cancer