Fluorescence contrast

The synthesis and characterization of a somatostatin receptor-specific peptide H2N-(DPhe)-cyclo[Cys-Phe-(D-Trp)-Lys-Thr-Cys]-Thr-OH, labeled with an indo-dicarbo- and an indotricarbocyanine dye at the V-terminal amino group were described in [34], The ability of these fluorescent contrast agents to target the somatostatin receptor was demonstrated by flow cytometry in vitro, wherein the indotricarbocyanine conjugate led to elevated cell-associated fluorescence on somatostatin receptor-expressing tumor cells. The intracellular localization was visualized using NIR fluorescence microscopy. 

The synthesis of a fluorescent photochromic system 274a with a high fluorescence contrast ratio by covalently joining a highly fluorescent zinc bis(acylamidine) allowing effective energy transfer from the excited state of the dye to the photochromic component has been reported (08JPP(A) (200)74). 

The best fluorescence contrast between tumor and normal tissue is obtained if the tumor accumulates porphyrins as much as possible and the normal tissue accumulates very few porphyrins. Fluorescence studies show that superficial lesions of BCC exhibit a maximum porphyrin fluorescence 6 h post ALA application, whereas in nodular lesions the observed intensity is highest after 2-4 h [15]. Detailed biochemical analyses prove that the respective fluorescence intensity correlates well with the extracted quantity of porphyrins [16-19]. In epithelial skin tumors, the porphyrin maxima are achieved 1-4 h after ALA application. In normal skin, porphyrin... 

E.M. Sevick-Muraca, A. Godavarty, J.P. Houston, A.B. Thompson, R. Roy, Near-infrared imaging with fluorescence contrast agents. In M.-A. Mycek, B.W. Pogue (eds.), Handbook of Biomedical Fluorescence, Marcel Dekker New York, Basel, 445-527 (2003)... 

A.B. Thompson, E.M. Sevick-Muracka, Near-infrared fluorescence contrast-enhanced imaging with intensified charge-coupled device homodyne detection measurement precision and accuracy, J. Biomed. Opt. 8, 111-120 (2003)... 

Figure 11.8 NSOM fluorescence contrast image (1 pm x 1 pm) of a bright spot/sphere on the Au blended P30T film (a) along with the emission spectra at different distances...

Fig. 3. Left Optical micrograph of a water condensation pattern on APTE (bright) squares surrounded by a trimethylsilane layer (HMDS, dark). Middle FITC-stained APTE/HMDS surface pattern with inverted fluorescence contrast. Right Photobleaching of the fluorescence at the FITC-stained surface pattern.

An image-processing-based method to quantify the rate of extravasation of fluorescent contrast agents from tumor microvessels was developed, and the effect of combretastatin A-4-P... 

In situ methods of quantification are based on visual, manual, or instrumental measurements of spots directly on the layer. In addition to the above requirements, in situ determination requires that a detection reagent, if needed, be chosen that produces a zone (colored or fluorescent) contrasting sharply with the background the reagent must be applied uniformly, usually by dipping the intensity of the zone must be reproducible and proportional to the amount of substance present and the reagent must react completely with the highest concentration of... 

Higgins, D. A., X. Liao, J. E. Hall and E. Mei (2001). "Simultaneous near-field optical birefringence and fluorescence contrast sqjplied to the study of dye-doped polymer-dispersed liquid crystals." Journal of Physical Chemistry B 105(25) 5874-5882. 

It is anticipated that real-time and accurate diagnosis of small-sized colorectal cancers can be realized through the observation of a clear fluorescence contrast between the normal and tumor tissues after intracolonic administration of the imaging agent under a standard florescence endoscope with or without magnification. 

K. V El-Naggar, A. K. Gillenwater, A. M. Richards-Kortum, R. R. A far-red fluorescent contrast agent to image epidermal growth factor receptor expression. Photochem. Photobiol. 2004, 79, 272-279. 

---