Carla Conti

Microimaging FTIR of head and neck tumors. IV.

On continuing our studies on head and neck neoplasia, specimens from salivary gland tumors have been explored by using infrared microimaging spectroscopy to discern healthy from neoplastic tissues. Samples with Warthin tumor, epithelial displasia, marginal B‐cell lymphoma, low‐grade adenocarcinoma, and adenoid cystic carcinoma pathologies have been investigated by using conventional light sources. Changes were monitored at the molecular level, probing spectral markers such as Amide I and II, phosphate, nucleic acids, and carbohydrates vibrational modes. In all cases, supervised and unsupervised spectral analyses resulted in satisfactory agreement with histopathological findings. Microsc. Res. Tech., 2009.

FT-IR study of two [2-oxo-pyrrolidin-4-yl]carboxylate diastereomers in different solvent systems

Abstract The infrared study of the solvent effect on two diasteroisomeric (3R)- and (3S)-1-[(R)-1-phenylethyl]-2-oxo-pyrrolidin-4-yl-carboxylates ( A and B ) acting as homo- β -proline inhibitory neurotransmitter precursors, is reported. Apart from the slight red shift of the carbonyl bands of A , the interactions of the title compounds with the solvents are comparable. In hydroxylic solvents, the solutes are hosts in intermolecularly H-bonded alcohol clusters, the percentage of specific solute–solvent interaction being higher for compound A . This result confirms theoretical findings and X-ray diffraction studies.

Histological and microscopy FT-IR imaging study on the proliferative activity and angiogenesis in head and neck tumours.

Micro Fourier transform infrared spectroscopy enables one to study small samples because of the high quality spectra that can be obtained. Biochemical and morphological changes between control and pathological tissues of head and neck tumours have been monitored drawing three-dimensional chemical maps of the main vibrational modes in the regions of interest. Comparison between spectral and histological data shows a satisfactory degree of accordance. Among all, proliferating and regressive states of the tumours can be identified.

FTIR microspectroscopy of melanocytic skin lesions: a preliminary study

Fourier transform infrared (FTIR) microspectroscopy has been employed to investigate benign (ordinary dermal and Reed nevi), dysplastic and malignant (invasive melanoma) skin lesions through the analysis of spectral changes of melanocytes as well as in the evaluation of the presence of melanin. Hierarchical cluster analysis and principal component analysis led to a satisfactory separation of malignant from dysplastic and normal melanocytes. Also, on enlarging the clustering with spectra from Reed and dermal nevi, the multivariate analysis segregated well the spectral data into discrete clusters, allowing the obtaining of reliable average spectra for analysis at the molecular level of the main groups or components responsible for the biological and biochemical changes. The most significant spectral characteristics appear to be related to differences in secondary protein structures, in nucleic acid conformation, in intra- and intermolecular bonding. In all cases, supervised and unsupervised spectral analyses resulted in satisfactory agreement with histopathological findings.

Vibrational mapping of sinonasal lesions by Fourier transform infrared imaging spectroscopy

Abstract. Fourier transform infrared imaging (FTIRI) is a powerful tool for analyzing biochemical changes in tumoral tissues. The head and neck region is characterized by a great variety of lesions, with different degrees of malignancy, which are often difficult to diagnose. Schneiderian papillomas are sinonasal benign neoplasms arising from the Schneiderian mucosa; they can evolve into malignant tumoral lesions (squamous cell carcinoma). In addition, they can sometimes be confused with the more common inflammatory polyps. Therefore, an early and definitive diagnosis of this pathology is mandatory. Progressing in our research on the study of oral cavity lesions, 15 sections consisting of inflammatory sinonasal polyps, benign Schneiderian papillomas, and sinonasal undifferentiated carcinomas were analyzed using FTIRI. To allow a rigorous description of these pathologies and to gain objective diagnosis, the epithelial layer and the adjacent connective tissue of each section were separately investigated by following a multivariate analysis approach. According to the nature of the lesion, interesting modifications were detected in the average spectra of the different tissue components, above all in the lipid and protein patterns. Specific band-area ratios acting as spectral markers of the different pathologies were also highlighted.

FT-IR of unsaturated β-amino acids in different solvents systems

Abstract The infrared study of the solvent effect on 2-methylen-3-phenyl-3-aminocarbonyl compounds, precursors of γ-hydroxy-β-amino acids, is reported. Intramolecular hydrogen bonding between NH and ester carbonyl group is present in apolar solvents, while in polar or/and protic solvents specific solute–solvent interactions are pre-dominant. In mixtures of chloroform and cyclohexane, various equilibria are present; the composition of the solute–solvent different complexes differs as the mol% of the solvent system changes. Conformational analysis confirms the infrared findings.

Microimaging FT-IR of Head and Neck Tumours. The case of salivary glands

This technique aims to further exploit the potentiality of infrared spectroscopy in isolating and defining spectral profiles in salivary glands attributable to various kinds of cancer: Warthin tumour, polymorphous low-grade adenocarcinoma, oral epithelium with dysplasia, adenoid cystic carcinoma, lymphoma, and the corresponding healthy tissues. Thirty three samples from patients with diagnosed salivary gland pathology were analyzed. Two adjacent sections of tissues (5 μm thickness) were used for both histopathological and FTIR analysis.

Infrared microscopy characterisation of carotid plaques and thyroid tissue biopsies

Fourier Transform Infrared Microscopy enables to study small samples by means of high quality spectra. Biochemical and morphological changes in carotid plaques and thyroid tissues have been displayed by drawing three-dimensional chemical maps of the main vibrational modes in regions of interest. A huge number of spectra were collected that allow to point out even subtle changes in the main components. Micro FT-IR spectroscopy is suited for in vivo clinical diagnostics, immunocytochemical analysis and ex vivo histological determinations to establish a suitable protocol for the study of lesions in human tissues, even at an early stage.

Damaged polyethylene acetabular cups microscopy FT-IR and mechanical determinations

Attenuated total reflectance (ATR) microscopy FT-IR and micro-hardness determinations have been used to study defects in polyethylene acetabular cups for hip prosthesis. The morphology of polymer chains and the distribution of crystalline zones can cause anomalous wear, granulomatosis and, consequently, the failure of the implant. The results have been corroborated by applying a structural analysis by means of the finite element method (FEM).

Spectroscopic and Mechanical Properties of a New Generation of Bulk Fill Composites

Objectives: The aims of this study were to in vitro evaluate the degree of conversion and the microhardness properties of five bulk fill resin composites; in addition, the performance of two curing lamps, used for composites polymerization, was also analyzed. Materials and Methods: The following five resin-based bulk fill composites were tested: SureFil SDR®, Fill Up!™, Filtek™, SonicFill™, and SonicFill2™. Samples of 4 mm in thickness were prepared using Teflon molds filled in one increment and light-polymerized using two LED power units. Ten samples for each composite were cured using Elipar S10 and 10 using Demi Ultra. Additional samples of SonicFill2, (3 and 5 mm-thick) were also tested. The degree of conversion (DC) was determined by Raman spectroscopy, while the Vickers microhardness (VMH) was evaluated using a microhardness tester. The experimental evaluation was carried out on top and bottom sides, immediately after curing (t0), and, on bottom, after 24 h (t24). Two-ways analysis of variance was applied to evaluate DC and VMH-values. In all analyses, the level of significance was set at p < 0.05. Results: All bulk fill resin composites recorded satisfactory DCs on top and bottom sides. At t0, the top of SDR and SonicFill2 showed the highest DCs-values (85.56 ± 9.52 and 85.47 ± 1.90, respectively), when cured using Elipar S10; using Demi Ultra, SonicFill2 showed the highest DCs-values (90.53 ± 2.18). At t0, the highest DCs-values of bottom sides were recorded by SDR (84.64 ± 11.68), when cured using Elipar S10, and Filtek (81.52 ± 4.14), using Demi Ultra. On top sides, Demi Ultra lamp showed significant higher DCs compared to the Elipar S10 (p < 0.05). SonicFill2 reached suitable DCs also on bottom of 5 mm-thick samples. At t0, VMH-values ranged between 24.4 and 69.18 for Elipar S10, and between 26.5 and 67.3 for Demi Ultra. Using both lamps, the lowest VMH-values were shown by SDR, while the highest values by SonicFill2. At t24, all DC and VMH values significantly increased. Conclusions: Differences in DC and VMH among materials are suggested to be material and curing lamp dependent. Even at t0, the three high viscosity bulk composites showed higher VMH than the flowable or dual curing composites.