Imaging adipocytes

The blue netlike surface in Plate 2 is also a contour map of a three-dimensional function. It represents a surface on which the electron density p(x,y,z) of adipocyte lipid binding protein (ALBP) is constant. Imagine that the net encloses 98% (or some specified value) of the protein s electron density, and so the net is in essence an image of the protein s surface. 

Fig. 6.14. Label-free chemical imaging of the penetration pathways for the topically applied drug diffusion enhancer dimethyl sulfoxide (DMSO) into mouse skin tissue Dual-frequency SRS imaging tuned into the characteristic vibration of DMSO at 670 cm-1 (bright gray regions) and the CH2 vibration of lipid-rich adipocytes at 2845 cm-1 (dark gray regions) at a depth of 65pm into the tissue. DMSO is hydrophilic and hence avoids lipid structures such as adipocytes (Image courtesy of Brian Saar, Chris Freudiger, and Wei Min [12])...

E. Gazi, P. Gardner, N. P. Lockyer, C. A. Hart, N. W. Clarke and M. D. Brown, Probing Lipid Translocation Between Adipocytes and Prostate Cancer Cells with Imaging FTIR Microspectroscopy, J. Lipid Res., 2007, 48, 1846 1856. 

The Raman image was collected from the same sample at a step size of 20 pm for comparison with the FT-IR image. Here, the spectral unmixing algorithm identified three main components. Beside proteins (cyan), the lipid fraction was further discriminated into cholesterol ester (yellow) and triglycerides (red) - with the latter assigned predominantly to adventitial adipocytes in perivascular tissue at the top and bottom. The concentrations of the components are presented in Figure 3.14e, the Raman spectra in 3.14 h. 

Figure 47. Black and white scan of an infrared image of human adipocyte cultures treated with rotenone and FCCP. Confluent human adipocytes were cultured in 96-well microtitre plates (50 pl/well). Dose responses are shown on the thermogenic effects of rotenone and FCCP on human adipocytes. The cells were treated for 10 min with either agent before the images were analyzed by infrared thermography. Representative data are presented from experiments performed in triplicate (Reproduced from Reference [14] with permission).

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