Fluoreszenzzystoskopie: Perspektiven in Klinik und Forschung

Zusammenfassung: Viele Studien bestätigen das klinische Interesse an der photodynamischen Diagnostik (PDD) zur Behandlung des nicht muskelinvasiven Harnblasenkarzinoms. Die PDD oder Fluoreszenzzystoskopie ist bei der Detektion okkulter Urothelkarzinome von großem Wert und mag einen positiven Einfluss auf die rezidivfreie Überlebenszeit und die Prognose haben. Dennoch wird ihre Spezifität mit hoher Variabilität, hauptsächlich in Relation mit den verschiedenen Krankheitsprofilen, in den einzelnen Studien angegeben. Neue Bildgebungstechniken zur Verbesserung der visuellen Beurteilung der Harnblasenwand werden daher entwickel

Angiostasis-induced vascular normalization can improve photodynamic therapy

In a recent issue, Cellular and Molecular Life Sciences published on the combination of photodynamic therapy (PDT) and anti-angiogenesis for the treatment of cancer [1]. In this paper, Bhuvaneswari and colleagues elegantly review this field. The idea behind combining these two therapeutic strategies is based on the observation that PDT can lead to vessel closure, and hence hypoxia, as well as other tissue damage resulting in inflammation. This combination of hypoxia and inflammation can in turn cause the enhanced release of angiogenic growth factors (vascular endothelial growth factor, VEGF) followed by the regrowth of the targeted neoplastic tissue. Thus, it appeared logical to try to block the VEGF pathways after PDT, for instance by applying antibodies against VEGF. This type of combination therapy is not limited to the treatment of cancer. Indeed, for the treatment of certain forms of exudative macular degeneration, recently published results from a phase II clinical study demonstrate great promise for the combination of PDT (Visudyne) together with anti-VEGF-A therapy using humanized antibody fragments (Lucentis). PDT as a monotherapy has clearly been shown to be effective in treating some early stage superficial cancers. However, for more advanced cancers, where PDT monotherapy appears to be less effective, the usefulness of the photodynamic approach followed by anti-VEGF therapy has not yet been extensively demonstrated in the clinic.ISSN:1420-682XISSN:1420-907

Low-Dose Vascular Photodynamic Therapy Decreases Tumor Interstitial Fluid Pressure, which Promotes Liposomal Doxorubicin Distribution in a Murine Sarcoma Metastasis Model.

INTRODUCTION: Solid tumors are known to have an abnormal vasculature that limits the distribution of chemotherapy. We have recently shown that tumor vessel modulation by low-dose photodynamic therapy (L-PDT) could improve the uptake of macromolecular chemotherapeutic agents such as liposomal doxorubicin (Liporubicin) administered subsequently. However, how this occurs is unknown. Convection, the main mechanism for drug transport between the intravascular and extravascular spaces, is mostly related to interstitial fluid pressure (IFP) and tumor blood flow (TBF). Here, we determined the changes of tumor and surrounding lung IFP and TBF before, during, and after vascular L-PDT. We also evaluated the effect of these changes on the distribution of Liporubicin administered intravenously (IV) in a lung sarcoma metastasis model. MATERIALS AND METHODS: A syngeneic methylcholanthrene-induced sarcoma cell line was implanted subpleurally in the lung of Fischer rats. Tumor/surrounding lung IFP and TBF changes induced by L-PDT were determined using the wick-in-needle technique and laser Doppler flowmetry, respectively. The spatial distribution of Liporubicin in tumor and lung tissues following IV drug administration was then assessed in L-PDT-pretreated animals and controls (no L-PDT) by epifluorescence microscopy. RESULTS: L-PDT significantly decreased tumor but not lung IFP compared to controls (no L-PDT) without affecting TBF. These conditions were associated with a significant improvement in Liporubicin distribution in tumor tissues compared to controls (P < .05). DISCUSSION: L-PDT specifically enhanced convection in blood vessels of tumor but not of normal lung tissue, which was associated with a significant improvement of Liporubicin distribution in tumors compared to controls

Fluoreszenzzystoskopie. Perspektiven in Klinik und Forschung [Fluorescence cystoscopy : Perspective in clinical practice and research = Cystoscopie de fluorescence : Perspective clinique et recherche]

Many studies confirm the clinical interest of photodynamic diagnostics (PDD) in non-muscle invasive bladder cancer management. PDD or fluorescence cystoscopy is not only of great value in occult urothelial cancer detection, but may have a positive impact on disease-free survival and prognosis. Yet, its specificity is found to be highly variable between studies mainly in relation to different disease profiles. New imaging techniques aimed at enhancing visualization to assess the bladder wall are under development

Multiplexed five-color molecular imaging of cancer cells and tumor tissues with carbon nanotube Raman tags in the near-infrared

Single-walled carbon nanotubes (SWNTs) with five different C13/C12 isotope compositions and well-separated Raman peaks have been synthesized and conjugated to five targeting ligands in order to impart molecular specificity. Multiplexed Raman imaging of live cells has been carried out by highly specific staining of cells with a five-color mixture of SWNTs. Ex vivo multiplexed Raman imaging of tumor samples uncovers a surprising up-regulation of epidermal growth factor receptor (EGFR) on LS174T colon cancer cells from cell culture to in vivo tumor growth. This is the first time five-color multiplexed molecular imaging has been performed in the near-infrared (NIR) region under a single laser excitation. Near zero interfering background of imaging is achieved due to the sharp Raman peaks unique to nanotubes over the low, smooth autofluorescence background of biological species.Comment: Published in Nano Researc

An objective comparison of detection and segmentation algorithms for artefacts in clinical endoscopy

We present a comprehensive analysis of the submissions to the first edition of the Endoscopy Artefact Detection challenge (EAD). Using crowd-sourcing, this initiative is a step towards understanding the limitations of existing state-of-the-art computer vision methods applied to endoscopy and promoting the development of new approaches suitable for clinical translation. Endoscopy is a routine imaging technique for the detection, diagnosis and treatment of diseases in hollow-organs; the esophagus, stomach, colon, uterus and the bladder. However the nature of these organs prevent imaged tissues to be free of imaging artefacts such as bubbles, pixel saturation, organ specularity and debris, all of which pose substantial challenges for any quantitative analysis. Consequently, the potential for improved clinical outcomes through quantitative assessment of abnormal mucosal surface observed in endoscopy videos is presently not realized accurately. The EAD challenge promotes awareness of and addresses this key bottleneck problem by investigating methods that can accurately classify, localize and segment artefacts in endoscopy frames as critical prerequisite tasks. Using a diverse curated multi-institutional, multi-modality, multi-organ dataset of video frames, the accuracy and performance of 23 algorithms were objectively ranked for artefact detection and segmentation. The ability of methods to generalize to unseen datasets was also evaluated. The best performing methods (top 15%) propose deep learning strategies to reconcile variabilities in artefact appearance with respect to size, modality, occurrence and organ type. However, no single method outperformed across all tasks. Detailed analyses reveal the shortcomings of current training strategies and highlight the need for developing new optimal metrics to accurately quantify the clinical applicability of methods

Novel colorectal endoscopic in vivo imaging and resection practice: a short practice guide for interventional endoscopists

Colorectal cancer remains a leading cause of cancer death in the UK. With the advent of screening programmes and developing techniques designed to treat and stage colorectal neoplasia, there is increasing pressure on the colonoscopist to keep up to date with the latest practices in this area. This review looks at the basic principles behind endoscopic mucosal resection and forward to the potential endoscopic tools, including high-magnification chromoscopic colonoscopy, high-frequency miniprobe ultrasound and confocal laser scanning endomicroscopic colonoscopy, that may soon become part of routine colorectal cancer management