Autistic Spectrum Disorder (ASD), considered a neurological development disorder, is characterized by different degrees of deficit in communication, social interaction, and learning, accompanied by repetitive and stereotyped patterns of behavior. The diagnosis of ASD is extremely complex due to the unknown etiopathogenesis and the diversity of symptoms presented by the individuals. This study aimed to evaluate the effectiveness of Fourier Transform Infrared Spectroscopy (FT-IR) as a tool for the diagnosis of ASD in saliva. Saliva samples from 14 volunteers, 7 with ASD (G-A) and 7 Neurotypical (G-N) were analyzed. The collected samples were centrifuged, 20 µL of supernatant was deposited on calcium fluoride (CaF2) windows and dehydrated for 10 min. The FT-IR spectra were obtained by a spectrophotometer coupled to a microscope, in the spectral range of 4000 cm-1 - 900 cm-1 , with 32 scans, and spectral resolution of 4 cm-1 . A total of 112 spectra were collected, and their averages were submitted to Cluster analysis by the second derivative, aiming to group the results by similarity. FT-IR Spectroscopy was able to separate approximately 86% of the samples in the corrected group. The results showed an increase in bands related to proteins and hormones. Individuals diagnosed with ASD often have increased levels of stress, difficulty in interpersonal relationships, and reduced salivary flow compared to neurotypical individuals. ASD patients present a higher concentration of proteins and cortisol release in the saliva. FT-IR spectroscopy is a promising tool to differentiate saliva samples from ASD patients from neurotypical individuals.
The Raman-based optical diagnosis of normal cervix, inflammative cervix (cervicitis), and cervical intraepithelial neoplasia was investigated on samples of 63 patients. The main alterations were found in the 857 cm−1 (CCH deformation aromatic); 925 cm−1 (C–C stretching); ~1247 cm−1 (CN stretch, NH bending of Amide III); 1370 cm−1 (CH2 bending); and 1525 cm−1 (C=C/C=N stretching) vibrational bands in accordance with previously reported in the literature comparing normal and malignant cervical tissue. The statistical analysis (principal components analysis, clustering, and logistic regression models) applied to the spectral data indicated that the full discrimination among normal and neoplastic tissues of cervix by Raman optical biopsy is seriously affected by the presence of inflammatory infiltrates, which increases the false-positive rate. This fact is specially relevant once cervicitis is a very common state (noncancerous) of the cervix of sexually active woman. The results suggest that, for the correct Raman-based diagnosis of normal cervix from cervical intraepithelial neoplasia, it is necessary to use an auxiliary way to discriminate the contribution from the inflammatory infiltrates.
The histogenesis of the breast Paget's disease was investigated by the optical diagnosis technique using
Raman spectroscopy. A total of 15 spectra of the associated breast lesion, 21 spectra of the eczematoid
skin lesion and 396 spectra of invasive breast cancer not otherwise specified were compared by
clustering the spectral data between 800 - 1800 cm-1 at level of similarity of 95%, using a correlation
distance measurement by computing the covariance matrix. The Raman spectral-biochemical
characterization of invasive breast cancer and breast Paget's disease with eczematoid skin lesion
associated with underlying invasive breast lesion tissues enabled one concludes that the parenchymal
disease had similar characteristics to the skin's Paget lesion. This could indicate a similar histogenesis
for both. Thus, the findings of the present work adds a relevant experimental evidence that agrees with
the epidermotropic theory of Paget's disease, that states that the cells originate in the breast ducts and
migrate to the nipple's skin.
The Fourier transform (FT)-Raman spectroscopy technique is used to assess the biochemical alterations that occur in the degenerative process of the rotator cuff supraspinatus tendon. The main alterations observed occur in the glycine, proline, hydroxyproline, cysteine, cistine, phenylalanine, tyrosine, collagen I and III, nucleic acid, lipids, glycosaminoglycans, and metalloproteinases bands. An increasing intensity for these bands is found in degenerated tendons, a finding well correlated with hyaline state and cellular activity. Statistical analysis (principal components analysis and clustering) shows a clear separation of the spectra into nonhyalinized and hyalinized clusters, which enables the construction of a binary diagnosis model based on logistic regression. Best diagnosis provided a sensitivity of 66.0% and a specificity of 74.7% with 79.6% concordant pairs. The discriminating power of the diagnostic test is assessed by computing the area under the receiving-operator characteristic curve (AUC), which indicates good accuracy (AUC=0.81). In principle, these results indicate that Raman spectroscopy can be used as an auxiliary aid to improve shoulder tendon surgery quality by guiding anchoring onto more healthy (nonhyaline) pieces of tendons. This should contribute to a decrease in the current high rerupture rate (13 to 68%) for this procedure.
Raman Spectroscopy was used to examine the distribution of the mineral and organic components in the human dentin before and after the chemical and thermal etching process. Polished dentin disks (n = 6/group) with 4mm thickness from twelve third molars were irradiated with Er:YAG laser. The dentin disks were prepared by polishing through a series of SiO2 papers with water and cleaned by ultrasonic system. Four pretreatment were performed. The disks were etched with 37% phosphoric acid (group I), Er:YAG laser 80mJ, 3Hz, 30s. (group II), Er:YAG laser 120mJ, 3Hz, 30s. (group III) and Er:YAG laser 180mJ, 3Hz, 30s. (group IV). The Raman spectra obtained from normal and treated dentin were analyzed. Attention was paid to the mineral PO4 (962 cm-1), CO3 (1073 cm-1) and to the organic component (1453cm-1). Raman spectroscopy showed that the mineral and organic dentin content were more affected in autoclaved teeth than in the specimens treated by Thymol. Peak area reduction in the specimens treated by Thymol in group I and II showed to be the most conservative procedures regarding to changes in organic and inorganic dentin components. Pulse energies of 120 and 180mJ showed to produce more reduction in the organic and inorganic content associated with more reduction in the peak areas at 960 and 1453cm-1.
FT-Raman spectroscopy is a modern analytical tool and it is believed that its use for skin cancer diagnosis will lead to several advantages for patients, e.g., faster results and a minimization of invasivity. This article reports results of an ex Vivo study of the FT-Raman spectra regarding differentiation between non-diseased and malignant human skin lesions, Basal Cell Carcinoma (BCC). A Nd: YAG laser at 1064nm was used as the excitation source in the FT-Raman, RFS 100/S Spectrometer, Bruker. Thirty-nine sets of human skin samples, 18 histopathologically diagnosed as non-diseased, and 21 as BCC, were obtained during routine therapeutic procedures required by the primary disease. No sample preparation was needed to promote the FT-Raman spectra collection. The main spectral features, which may differentiate the sample, were found in the shift region of Amide I (1640 to 1680 cm-1), Amide III (1220 to 1330cm-1), proteins and lipids (1400 to 1500 cm-1), amino acids (939 to 940 cm-1) and deoxyribonucleic acid (1600 to 1620cm-1). Principal Components Analysis (PCA) was applied to FT-Raman spectra of Basal Cell Carcinoma. Analysis was performed on mean-normalized and mean-centered data of the non-diseased skin and BCC spectra. The dynamic loading of PCA was expanded into 2D contour by calculating a variance-covariance matrix. PCA was used to verify the statistical differences in the sample. This technique applied over all samples identified tissue type within 83% of sensitivity and 100% specificity. The PCA technique proved efficient for analysis in skin tissue ex vivo, results were significant and coherent.
Raman Spectroscopy was used to examine the distribution of the organic components in the human dentin before and after the chemical and thermal etching process. Polished dentin disks (n = 6/group) with 4mm thickness from twelve third molars were irradiated with Er:YAG laser. The dentin disks were prepared by polishing through a series of SiO2 papers with water and cleaned by ultrasonic system. Four pretreatment were performed. The disks were etched with 37% phoshporic acid for 15 s (group 1), Er:YAG laser 80 mJ, 3Hz, 30s. (group II), Er:YAG laser 120 mJ, 3Hz, 30s. (group III) and Er:YAG laser 180mJ, 3Hz, 30s. (group IV). The Raman spectra obtained from normal and treated dentin were analyzed. Attention was paid to the organic component (1453cm-1). Raman spectroscopy showed that the organic dentin content were more affected in autoclaved teeth than in the specimens treated by Thymol. Peak area reduction in the specimens treated by Thymol in group I and II showed to be the most conservative procedures regarding to changes in organic dentin components. Pulse energies of 120 and 180 mJ showed to preduce more reduction in the organic content associated with more reduction in the peak areas at 1453 cm-1.
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