Laser-induced fluorescence and X-ray spectral analysis of carious process in hard dental tissues.

Morphological and spectral X-ray analysis of carious and noncarious extracted teeth showed the patterns of dentin ossification in caries of different degree. Parietal ectopic ossification of the canal and cavity lumens in stages III and IV dental caries is regarded as a specific structural marker of pathological regeneration. The X-ray spectral analysis showed that the progress of carious process is paralleled by loss of mineral components. Laser-induced fluorescent study of tissues in extracted teeth showed 4 spectral bands corresponding to mineral and protein components of the tooth. The progress of carious process was associated with reduction of the fluorescence intensities of the spectral bands characteristic of dental collagen and mineral components.

[Transformation of bioprosthesis-artery anastomotic area after blood exposure: the effect of suture material].

Vascular graft implantation is accompanied with tissue reaction which is determined partially by the nature of suture material. In experiments in vitro edges of arterial diepoxid-preserved bioprostheses were sutured with Prolene filament, nickelide-titanium wire (TiNi) or absorbable polydioxanone monofilament (PDS). Morphological changes in anastomotic area after blood exposure were assessed with scanning electronic microscope. Protein deposits in anastomotic area were detected 5 min after blood exposure, being more loose and bulky around Prolene sutures. The protein layer became more compact 120 min since blood exposure. Most homogeneous protein sorption was over TiNi-sutured anastomoses. Suture material affected blood cells as well - some red cells have transformed into echinocytes. Heparin-modified samples demonstrated less negative impact of suture material in anastomotic area. The worst results after 120 min of blood exposure were obtained for PDS filaments.

Influence of mineral components on laser-induced fluorescence spectra of calcified human heart-valve tissues.

Laser-induced fluorescence (LIF) spectra of calcified human heart-valve tissue and LIF spectra of macroscopic calcinosis fragments dissected from human heart valves were compared with LIF spectra of pig myocardium tissues. Excitation was provided by an excimer laser with wavelength lambda = 248 nm. Fluorescence bands that were due to mineral and organic tissue components were identified by measurement of LIF spectra of macroscopic fragments of calcified tissues that had been heat treated at 700 degrees C. The studies showed that LIF spectra of calcified tissues include fluorescence emission from tryptophan, collagen, elastin, and a mineral component of tissue, hydroxylapatite. The observed differences in LIF spectra of normal and calcified tissues with different pathologies may result not only from calcification-induced changes in relative collagen and elastin concentrations but also from additional (absent in normal heart tissue) fluorescence of hydroxylapatite. The calcification-induced changes in the LIF spectra of human heart-valve tissues, characterized by a 330/450 nm ratio, were found to be quite appreciable, which suggests that this ratio can be used with LIF measurements to evaluate the degree of heart-tissue calcification.