**2. Materials and methods**

20 samples from carotid and coronary arteries from patients (60-85 years old) who underwent endarterectomy were used for the study (Figure 4). Representative sections of the Carotid atheromatic plaques and coronary arteries were restored in formalin. The FT-IR spectra were obtained with a Nicolet 6700 thermoscientific spectrometer, connected to an attenuated total reflection, ATR, accessory. For each region a series of spectra were recorded and every spectrum consisted of 120 co-added spectra at a resolution of 4 cm−1 and the OMNIC 7.1 software was used for data analysis. All the spectra for each patient and region were obtained in the same way. The analysis of bacterial morphology was performed by Scanning Electron Microcopy –SEM using a Fei Co at an accelerating potential 25 kV. Uncoated freeze dried cells were examined with LFD and BSED detectors. Qualitive elemental data analysis of the samples was determined by EDX (Energy-dispersive X-ray spectroscopy).

Fig. 4. Sample from carotid arteryA: atheromatous plaque, B: adventitia , C: intima
