Detection of skin wrinkles and quantification of roughness using a novel image processing technique from a dermatoscope device.

OBJECTIVE: Cutaneous relief analysis is crucial in the development of new skincare products, as well as in the evaluation of dermatological treatments. The analysis can be performed by qualitative or quantitative methods. We propose a new algorithm to detect wrinkles and quantify skin roughness by image processing from a dermatoscope. METHODS: A clinical study was carried out with 33 research participants, and images were collected with the dermatoscope and PRIMOS equipment for wrinkle evaluation at two different times: Day 0 (D0) and 45 days (D45) after the use of a dermocosmetic product. Later, a new algorithm was developed to detect wrinkles in the acquired images by applying filters and image transformations that generate a segmented image highlighting the wrinkles. A roughness calculation method is proposed from the pixels belonging to wrinkles. RESULTS: Correlation between the values obtained by the PRIMOS equipment and the proposed system was verified. No correlation was found for data obtained at D0; however, there was correlation at time D45 by Spearman's similarity coefficient. By comparing roughness between times D0 and D45, the treatment was statistically significant for both PRIMOS and the proposed methodology data. CONCLUSION: The wrinkle detection algorithm, in addition to the roughness calculation, demonstrated a sensitivity comparable to the PRIMOS system in evaluating the effectiveness of the dermocosmetic treatment. SIGNIFICANCE: Considering the simplicity of the dermatoscope design compared to other established devices such as PRIMOS, the proposed system is promising as an alternative for dermatological evaluations.

In vivo Raman spectroscopic characteristics of different sites of the oral mucosa in healthy volunteers.

OBJECTIVES: Investigate the biochemistry of in vivo healthy oral tissues through Raman spectroscopy. We aimed to characterize the biochemical features of healthy condition in oral subsites (buccal mucosa, lip, tongue, and gingiva) of healthy subjects. More specifically, we investigated Raman spectral characteristics and biochemical content of in vivo healthy tissues on Brazilian population. This characterization can be used to better define normal tissue and improve the detection of oral premalignant conditions in future studies. MATERIALS AND METHODS: For spectroscopic analysis a Raman spectrometer (Kaiser Optical Systems imaging spectrograph Holospec, f / 1.8i-NIR) coupled with a laser 785 nm, 60 mW was used. Raman measurements were obtained by means of an optical fiber (EMVision fiber optic probe) coupled between the laser and the spectrometer. Three spectra per site were acquired from the lip, buccal mucosa, tongue, and gingiva of ten healthy volunteers. This resulted in 30 spectra per oral sub-site and in total 120 spectra. RESULTS: We report detailed biochemical information on these subsites and their relative composition based on deconvolution studies of their spectra. Finally, we also report classification efficiency of 61, 83, 41, and 93% for buccal, gingiva, lip, and tongue respectively after applying multivariate statistical tools. CONCLUSIONS: We quantitated the contribution of various biochemicals in terms of percentage, and this will enable comparison not only across anatomical sites but also across studies. Raman spectroscopy can rapidly probe tissue biochemistry of healthy oral regions. Moreover, the study suggests the possibility of using Raman spectroscopy combined with signal processing and multivariate analysis methods to differentiate the oral sites in healthy conditions and compare with pathological conditions in future studies. CLINICAL RELEVANCE: The spectral characterization of the healthy condition of oral tissues by a noninvasive, label-free, and real-time analytical techniques is important to create a spectral reference for future diagnosis of pathological conditions.

Effect of non-thermal atmospheric plasma on the dentin-surface topography and composition and on the bond strength of a universal adhesive.

This study investigated the effect of application of non-thermal atmospheric plasma (NTAP) on the topography and composition of the dentin surface, as well as the microtensile bond strength (µTBS) of a universal adhesive to NTAP-treated dentin. Exposed flat dentin surfaces from human third molars were either treated with NTAP for 10 and 30 s or untreated (control). The dentin-surface topography and chemical composition were characterized by atomic force microscopy (n = 3) and Raman confocal spectroscopy (n = 5), respectively. The µTBS (n = 8) of Scotchbond Universal to dentin was determined after storage for 24 h and 1 yr, either by direct water exposure or under simulated pulpal pressure. In-situ zymography was used to evaluate the influence of NTAP on the dentin-enzymatic activity. Non-thermal atmospheric plasma produced no remarkable topographical or chemical alterations at the dentin surface; only the amount of phosphate decreased following 10 s of treatment with NTAP. After 1 yr of direct water exposure, the µTBS of NTAP-treated specimens did not differ statistically significantly from that of untreated controls, whereas simulated pulpal pressure-aging resulted in a significantly higher µTBS for NTAP-treated dentin. The dentin-enzymatic activity appeared to be treatment-dependent, but the untreated controls showed more intense fluorescence within the hybrid layer. Scotchbond Universal maintained its µTBS strength after 1 yr of direct water exposure and simulated pulpal pressure, although remarkable statistical differences between treatments were observed depending on the aging condition.

Raman spectroscopic analysis of oral cells in the high wavenumber region.

Raman spectroscopy can provide a molecular-level signature of the biochemical composition and structure of cells with submicrometer spatial resolution and could be useful to monitor changes in composition for early stage and non-invasive cancer diagnosis, both ex-vivo and in vivo. In particular, the fingerprint spectral region (400-1800cm-1) has been shown to be very promising for optical biopsy purposes. However, limitations for discrimination of dysplastic and inflammatory processes based on the fingerprint region have been demonstrated. In addition, the Raman spectral signal of dysplastic cells is one important source of misdiagnosis of normal versus pathological tissues. The high wavenumber region (2800-3600cm-1) provides more specific information based on NH, OH and CH vibrations and can be used to identify the subtle changes which could be important for discrimination of samples. In this study, we demonstrate the potential of the high-wavenumber spectral region in this context by collecting Raman spectra of nucleolus, nucleus and cytoplasm from oral epithelial cancer (SCC-4) and dysplastic (DOK) cell lines and from normal oral epithelial primary cells, in vitro, in water immersion, which were then analyzed by principal components analysis as a method to discriminate the spectra. Analysis was performed before and after digital subtraction of the bulk water signal. In the normal cell line, the three subcellular regions are well differentiated before water subtraction, although the discrimination of the two nuclear regions is less well defined after water subtraction. Comparing the respective subcellular regions of the three cell lines, before water subtraction, the cell lines can be discriminated using sequential PCA and Feature Discriminant Analysis with up to ~100% sensitivity and 97% specificity for the cytoplasm, which is improved to 100% sensitivity and 99% specificity for the nucleus. The results are discussed in terms of discrimination comparing the CH vibrational modes of nucleic acids, proteins and lipids. The potential role of the OH vibrations, considering free water and confined water, in the discrimination of cell cultures and pathological processes are also discussed.

Complex nanoemulsion for vitamin delivery: droplet organization and interaction with skin membranes.

Lipid nanoemulsions are promising nanomaterials for drug delivery applications in food, pharmaceutical and cosmetic industries. Despite the noteworthy commercial interest, little is known about their supramolecular organization, especially about how such multicomponent formulations interact with cell membranes. In the present work, coarse-grained molecular dynamics simulations have been employed to study the self-assembly of a 15-component lipid nanoemulsion droplet containing vitamins A and E for skin delivery. Our results display aspects of the unique "onion-like" agglomeration between the chemical constituents in the different layers of the lipid nanodroplet. Vitamin E molecules are more concentrated in the center of the droplet together with other hydrophobic constituents such as the triglycerides with long tails. On the other hand, vitamin A occupies an intermediate layer between the core and the co-emulsifier surface of the nanodroplet, together with lecithin phospholipids. Coarse-grained molecular dynamics simulations were also performed to provide insight into the first steps involved in absorption and penetration of the nanodroplet through skin membrane models, representing an intracellular (hair follicle infundibulum) and intercellular pathway (stratum corneum) through the skin. Our data provide a first view on the complex organization of commercial nanoemulsion and its interaction with skin membranes. We expect our results to open the way towards the rational design of such nanomaterials.

Effects of heating by steam autoclaving and Er:YAG laser etching on dentin components.

The simultaneous need for infection-control protocols in sample preparations and for safe laser irradiation parameters prompted this study about the effects of heat produced by both sample sterilization and laser etching on dentin components. The dentin was exposed on 30 bovine incisors, and then divided into two main groups: autoclaved (group A) or thymol treatment (group B). The surface of the dentin was schematically divided into four areas, with each one corresponding to a treatment subgroup. The specimens were either etched with phosphoric acid (control-CG) or irradiated with Er:YAG laser (subgroups: I-80 mJ, II-120 mJ, and III-180 mJ). Elemental distribution maps were done by energy-dispersive X-ray fluorescence (µ-EDXRF) on each treatment area. The dentin surface in depth was exposed and line-scan maps were performed. The B_CG treatment produced the best distribution of calcium (Ca) and phosphorus (P) content throughout the dentin surface. Er:YAG laser etching produced irregular patterns of elemental distribution in the dentin. Laser energies of 120 and 180 mJ produced the highest maximum calcium values. The Er:YAG laser energy of 180 mJ produced a localized increase in Ca and P content on the superficial layer of the dentin (∼ 0-0.10 mm). The autoclaving treatment of samples in experiments is not recommended since it produced damaging effects on dentin components. Er:YAG laser irradiation produced a heterogeneous Ca and P distribution throughout the dentin surface with areas of increased Ca concentration, and this may affect clinically the permeability, solubility, or adhesive characteristics of dental hard tissues with restorative procedures.

Conversion degree of indirect resin composites and effect of thermocycling on their physical properties.

PURPOSE: This study evaluated the degree of conversion (DC) of four indirect resin composites (IRCs) with various compositions processed in different polymerization units and investigated the effect of thermal aging on the flexural strength and Vicker's microhardness. MATERIALS AND METHODS: Specimens were prepared from four IRC materials, namely Gr 1: Resilab (Wilcos); Gr2: Sinfony (3M ESPE); Gr3: VITA VMLC (VITA Zahnfabrik); Gr4: VITA Zeta (VITA Zahnfabrik) using special molds for flexural strength test (N = 80, n = 10 per group) (25 x 2 x 2 mm(3), ISO 4049), for Vicker's microhardness test (N = 80, n = 10 per group) (5 x 4 mm(2)) and for DC (N = 10) using FT-Raman Spectroscopy. For both flexural strength and microhardness tests, half of the specimens were randomly stored in distilled water at 37 degrees C for 24 hours (Groups 1 to 4), and the other half (Groups 5 to 8) were subjected to thermocycling (5000 cycles, 5 to 55 +/- 1 degree C, dwell time: 30 seconds). Flexural strength was measured in a universal testing machine (crosshead speed: 0.8 mm/min). Microhardness test was performed at 50 g. The data were analyzed using one-way and two-way ANOVA and Tukey's test (alpha= 0.05). The correlation between flexural strength and microhardness was evaluated with Pearson's correlation test (alpha= 0.05). RESULTS: A significant effect for the type of IRC and thermocycling was found (p= 0.001, p= 0.001) on the flexural strength results, but thermocycling did not significantly affect the microhardness results (p= 0.078). The interaction factors were significant for both flexural strength and microhardness parameters (p= 0.001 and 0.002, respectively). Thermocycling decreased the flexural strength of the three IRCs tested significantly (p < 0.05), except for VITA Zeta (106.3 +/- 9.1 to 97.2 +/- 14 MPa) (p > 0.05) when compared with nonthermocycled groups. Microhardness results of only Sinfony were significantly affected by thermocycling (25.1 +/- 2.1 to 31 +/- 3.3 Kg/mm(2)). DC values ranged between 63% and 81%, and were not significantly different between the IRCs (p > 0.05). While a positive correlation was found between flexural strength and microhardness without (r = 0.309) and with thermocycling (r = 0.100) for VITA VMLC, negative correlations were found for Resilab under the same conditions (r =-0.190 and -0.305, respectively) (Pearson's correlation coefficient). CONCLUSION: Although all four IRCs presented nonsignificant DC values, flexural strength and microhardness values varied between materials with and without thermocycling.

Unraveling the molecular and cellular mechanisms of stretch marks.

BACKGROUND: Striae distensae, commonly known as stretch marks, are cutaneous lesions that accompany the hormonal upheavals of the major stages of life: puberty and pregnancy. Stretch marks occur in 90% of women, and they appear as red or purple lines that slowly fade to pale lines on the skin. There have been few studies regarding stretch mark origins, and new preventive and corrective treatments are needed. AIMS: The aim of this work was to understand the primary genes and proteins involved in the regulation of striae compared to normal skin and to identify the differentially expressed genes and biochemical aspects of SA and SR Importantly, this is the first published study to use a molecular high-throughput approach combined with in vivo evaluation. METHODS: In this study, we analyzed the molecular differences between skin with and without stretch marks (rubra [SR] and alba [SA]) of female volunteers using DNA microarray (Whole Human Genome Microarray Kit, 4×44 K, Agilent Technologies) analyses of cutaneous biopsies (2 mm) and in vivo confocal Raman spectroscopy of selected buttock regions, a technique recently introduced as a noninvasive skin evaluation method. RESULTS: We identified gene expression alterations related to ECM, cellular homeostasis, and hormones such as secretoglobulins. Spectral analyses of collagen, fibrillin, and glycosaminoglycans were conducted by Raman spectroscopy at different skin depths. The main differences observed when comparing skin with and without stretch marks were at depths between 75 and 95 µm, corresponding to the dermal-epidermal junction and dermis regions and showing differences between normal skin and stretched skin regarding collagen, collagen hydration, and elastin fibers. CONCLUSION: The results obtained by RNA and protein analyses are complementary and show that significant changes occur in the skin affected by stretch marks. These results suggest new strategies and opportunities to treat this skin disorder and for the development of new and eficiente cosmetic products.

Can ethanol affect the cell structure? A dynamic molecular and Raman spectroscopy study.

The role that tobacco consumption plays in the etiology of oral cancer carcinogenesis, and of alcohol consumption acting as a co-factor, have been well established. However, in recent years, the contribution of alcohol consumption alone to oral cancer has been proposed. In fact, a high percentage of patients who develop oral cancer have both habits (tobacco and alcohol consumption), and other small patient groups only consume alcohol or do not have any other identifiable bad habits. In the present study we demonstrate, using a combination of dynamic molecular modelling and Raman spectroscopy, that ethanol has a significant effect on oral cells in vitro, mainly interacting with the lipids of the cell membrane, changing their conformation. Thus, it is possible to conclude that ethanol can affect the cell permeability, and by consequence serve as a possible trigger in oral carcinogenesis.

Thyroid tissue analysis through Raman spectroscopy.

The diagnosis of thyroid pathologies is usually made by cytologic analysis of the fine needle aspiration (FNA) material. However, this procedure has a low sensitivity at times, presenting a variation of 2-37%. The application of optical spectroscopy in the characterization of alterations could result in the development of a minimally invasive and non-destructive method for the diagnosis of thyroid diseases. Thus, the objective of this work was to study the biochemical alterations of tissues and hormones (T3 and T4) of the thyroid gland by means of molecular vibrations probed by FT-Raman spectroscopy. Through the discriminative linear analysis of the Raman spectra of the tissue, it was possible to establish (in percentages) the correct classification index among the groups: goitre adjacent tissue, goitre nodular region, follicular adenoma, follicular carcinoma and papillary carcinoma. As a result of the comparison between the groups goitre adjacent tissue versus goitre nodular region, an index of 58.3% of correct classification was obtained; this percentage was considered low, and it was not possible to distinguish the Raman spectra of these groups. Between goitre (nodular region and adjacent tissue) versus papillary carcinoma, the index of correct classification was 64.9%, which was considered good. A relevant result was obtained in the analysis of the benign tissues (goitre and follicular adenoma) versus malignant tissues (papillary and follicular carcinomas), for which the index was 72.5% and considered good. It was also possible, by means of visual observation, to find similar vibrational modes in the hormones and pathologic tissues. In conclusion, some biochemical alterations, represented by the FT-Raman spectra, were identified that could possibly be used to classify histologic groups of the thyroid. However, more studies are necessary due to the difficulty in setting a standard for pathologic groups.

DNA Extraction Systematics for Spectroscopic Studies.

Study of genetic material allows the comprehension the origin of the many biochemical changes that follow diseases, like cancer, promoting the development of early preventive inquiry and more efficient individual treatments. Raman spectroscopy can be an important tool in DNA study, since it allows probe molecular vibrations of genetic material in a fast way. The present work established a systematic way for extract DNA in suitable concentrations and structural integrity allowing studies by Raman spectroscopy or other spectroscopic technique, including bio-analytical sensors for probing genetic alterations.

Erratum: Raman spectral post-processing for oral tissue discrimination - a step for an automatized diagnostic system: erratum.

[This corrects the article on p. 5218 in vol. 8, PMID: 29188115.].

Comparative study of transdermal drug delivery systems of resveratrol: High efficiency of deformable liposomes.

Trans-resveratrol (3, 5, 4' trihydroxystilbene, RSV) is a natural compound that shows antioxidant, cardioprotective, anti-inflammatory and anticancer properties. The transdermal, painless application of RSV is an attractive option to other administration routes owing to its several advantages like avoiding gastrointestinal problems and first pass metabolism. However, its therapeutic potential is limited by its low solubility and low stability in water and the reduced permeability of stratum corneum. To overcome these inconveniences the encapsulation of this compound in a drug delivery system is proposed here. In order to find the best carrier for transdermal application of RSV various liposomal nanoparticulate carriers like conventional liposomes (L-RSV), deformable liposomes (LD-RSV), ultradeformable liposomes (LUD-RSV) and ethosomes (Etho-RSV) were assayed. Transmission electron microscopic (TEM) and dynamic light scattering (DLS) studies were performed to analyze the surface morphology of these carriers. Structural characterization for these formulations was performed by confocal Raman spectroscopy. The spectroscopic results were analysed in conjunction with calorimetric data to identify the conformational changes and stability of formulations in the different nanoparticles induced by the presence of RSV. Comparison of the results obtained with the different carrier systems (L-RSV, LD-RSV, LUD-RSV and Etho-RSV) revealed that the best RSV carrier was LD-RSV. The increase in the fluidity of the bilayers in the region of the hydrophobic chains of the phospholipid by ethanol probably facilitates the accommodation of the RSV in the bilayer and contributes to the improved encapsulation of RSV without affecting the mobility of this carrier.

Raman spectral post-processing for oral tissue discrimination - a step for an automatized diagnostic system.

Most oral injuries are diagnosed by histopathological analysis of a biopsy, which is an invasive procedure and does not give immediate results. On the other hand, Raman spectroscopy is a real time and minimally invasive analytical tool with potential for the diagnosis of diseases. The potential for diagnostics can be improved by data post-processing. Hence, this study aims to evaluate the performance of preprocessing steps and multivariate analysis methods for the classification of normal tissues and pathological oral lesion spectra. A total of 80 spectra acquired from normal and abnormal tissues using optical fiber Raman-based spectroscopy (OFRS) were subjected to PCA preprocessing in the z-scored data set, and the KNN (K-nearest neighbors), J48 (unpruned C4.5 decision tree), RBF (radial basis function), RF (random forest), and MLP (multilayer perceptron) classifiers at WEKA software (Waikato environment for knowledge analysis), after area normalization or maximum intensity normalization. Our results suggest the best classification was achieved by using maximum intensity normalization followed by MLP. Based on these results, software for automated analysis can be generated and validated using larger data sets. This would aid quick comprehension of spectroscopic data and easy diagnosis by medical practitioners in clinical settings.

Photodynamic damage predominates on different targets depending on cell growth phase of Candida albicans.

Photodynamic inactivation (PDI) has been reported to be effective to eradicate a wide variety of pathogens, including antimicrobial-resistant microorganisms. The aim of this study was to identify the potential molecular targets of PDI depending on growth phase of Candida albicans. Fungal cells in lag (6h) and stationary (48h) phases were submitted to PDI mediated by methylene blue (MB) combined with a (662±21) nm-LED, at 360mW of optical power. Pre-irradiation time was 10min and exposure times were 12min, 15min and 18min delivering radiant exposures of 129.6J/cm2, 162J/cm2 and 194.4J/cm2, respectively, on a 24-well plate of about 2cm2 at an irradiance of 180mW/cm2. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force spectroscopy (AFS) and Fourier transform infrared spectroscopy (FT-IR) were employed to evaluate the photodynamic effect in young and old fungal cells following 15min of irradiation. Morphological analysis revealed wrinkled and shrunk fungal cell membrane for both growth phases while extracellular polymeric substance (EPS) removal was only observed for old fungal cells. Damaged intracellular structures were more pronounced in young fungal cells. The surface nanostiffness of young fungal cells decreased after PDI but increased for old fungal cells. Cellular adhesion force was reduced for both growth phases. Fungal cells in lag phase predominantly showed degradation of nucleic acids and proteins, while fungal cells in stationary phase showed more pronounced degradation of polysaccharides and lipids. Taken together, our results indicate different molecular targets for fungal cells in lag and stationary growth phase following PDI.

An FT-Raman, FT-IR, and Quantum Chemical Investigation of Stanozolol and Oxandrolone.

We have studied the Fourier Transform Infrared (FT-IR) and the Fourier transform Raman (FT-Raman) spectra of stanozolol and oxandrolone, and we have performed quantum chemical calculations based on the density functional theory (DFT) with a B3LYP/6-31G (d, p) level of theory. The FT-IR and FT-Raman spectra were collected in a solid phase. The consistency between the calculated and experimental FT-IR and FT-Raman data indicates that the B3LYP/6-31G (d, p) can generate reliable geometry and related properties of the title compounds. Selected experimental bands were assigned and characterized on the basis of the scaled theoretical wavenumbers by their total energy distribution. The good agreement between the experimental and theoretical spectra allowed positive assignment of the observed vibrational absorption bands. Finally, the calculation results were applied to simulate the Raman and IR spectra of the title compounds, which show agreement with the observed spectra.

In vivo confocal Raman spectroscopy and molecular dynamics analysis of penetration of retinyl acetate into stratum corneum.

OBJECTIVE: The purpose of this study is to elucidate the behavior of retinyl acetate in penetrating human skin without the presence of enhancers by using confocal Raman spectroscopy and molecular dynamics simulation. METHODS: In this study, in vivo confocal Raman spectroscopy was combined with molecular dynamics simulation to investigate the transdermal permeation of the aqueous suspension of retinyl acetate. RESULTS: Permeation was measured after 30min, and retinyl acetate was found up to 20µm deep inside the stratum corneum. The delivery of retinyl acetate inside a skin membrane model was studied by molecular dynamics. The membrane model that was used represented normal young skin containing a lipid bilayer with 25% ceramide, 36% fatty acid, 30% cholesterol, and 6% cholesterol sulfate. CONCLUSION: Spectroscopy data indicate that retinyl acetate permeates into the stratum corneum. Molecular dynamics data showed that retinyl acetate permeates in the membrane model and that their final location is deep inside the lipid bilayer. We showed, for the first time, a correlation between Raman permeation data and computational data.

Chemical, morphological and thermal effects of 10.6-microm CO2 laser on the inhibition of enamel demineralization.

Studies have shown that enamel can be modified by pulsed CO2 laser to form a more acid-resistant substrate. This study evaluated the effects of a 10.6-microm CO2 laser on enamel surface morphology and chemical composition as well as monitored intrapulpal temperature changes during irradiation. Human teeth were irradiated with fluences of 1.5-11.5 J/cm2, and pulpal thermal as well as chemical and morphological modifications on enamel were assessed. The teeth were submitted to a pH-cycling model, and the mineral loss was determined by means of cross-sectional microhardness. For all irradiated groups, intrapulpal temperature changes were below 3 degrees C. FT-Raman spectroscopy and scanning electron microscopy indicated that fluences as low as 6.0 J/cm2 were sufficient to induce chemical and morphological changes in enamel. Then, for fluences reaching or exceeding 10.0 J/cm2, laser-induced inhibitory effects on demineralization were observed. It was thus concluded that laser energy density in the range of 10.0 and 11.5 J/cm2 could be applied to dental enamel in order to produce chemical and morphological changes and reduce the acid reactivity of enamel without compromising the pulp vitality.

Molecular analysis of Er:YAG laser irradiation on dentin.

The aim of this study was to evaluate by dispersive Raman spectroscopy the mineral and organic components of human dentin before and after laser irradiation and acid etching. The occlusal enamel of six non-carious human third molars was removed providing 6 dentin discs, which were divided in four quadrants each of them receiving a different surface treatment: etching with a 37% phosphoric acid gel (control); irradiation by Er:YAG laser (KaVo Key Laser II) with 80 mJ, 3 Hz, 30 s (group I); 120 mJ, 3 Hz, 30 s (group II); and 180 mJ, 3 Hz, 30 s (group III). The Raman spectra of normal (untreated) and treated dentin were analyzed and the mineral and the organic component were evaluated. Results were submitted to statistical analysis by ANOVA and Tukey's test at 5% significance level. The minerals and organic content were less affected in the control group and group I (p>0.05). Group II presented more reduction in mineral content (p<0.01) whereas in group III the inorganic (p<0.05) and organic (p<0.01) content were more affected. Dispersive Raman spectroscopy provided valid information of dentin chemical constituents with non-chemical sampling preparation.

Raman spectroscopy study of atherosclerosis in human carotid artery.

Fourier-transform (FT)-Raman spectroscopy has been used for identification and evaluation of human artherosclerotic lesions, providing biochemical information on arteries. In this work, fragments of human carotid arteries postmortem were analyzed using a FT-Raman spectrometer operating at an excitation wavelength of 1064 nm, power of 200 mW, and spectral resolution of 4 cm(-1). A total of 75 carotid fragments were spectroscopically scanned and FT-Raman results were compared with histopathology. Discriminant analysis using Mahalanobis distance was applied over principal components scores for tissue classification into three categories: nonatherosclerotic, atherosclerotic plaque without calcification and with calcification. Nonatherosclerotic artery, atherosclerotic plaque, and calcified plaque exhibit spectral signatures related to biochemicals presented in each tissue type, such as bands of collagen and elastin (proteins), cholesterol and its esters, and calcium hydroxyapatite and carbonate apatite, respectively. Spectra of nonatherosclerotic artery were then classified into two groups: normal and discrete diffuse thickening of the intima layer (first group) and moderate and intense diffuse thickening of the intima layer (second group). FT-Raman could identify and classify the tissues found in the atherosclerotic process in human carotid in vitro and had the ability to identify alterations to the diffuse thickening of the intima layer and classify it depending on the intensity of the thickening.