Infrared Spectroscopy Based Study of Biochemical Changes in Saliva during Maximal Progressive Test in Athletes.

This study aims to explore biochemical changes in saliva during cardiorespiratory exercise using attenuated-total-reflectance-Fourier-transform-infrared-spectroscopy (ATR-FTIR). Saliva and blood samples were obtained from six athletes at rest, and after running at speeds of 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20 kilometers-per-hour (km/h) on a treadmill (maximal stress test). Saliva ATR-FTIR spectra were analyzed using deconvolution and multivariate analysis. Area-under-the-curve calculations suggest differential changes in glucose, lactate, protein, lipids, carbohydrate and phosphate content in saliva during the test. Increases in glucose and lactate levels with increasing speeds were verified by simultaneous measurement of blood glucose and lactate levels using standard equipment (Roche®). Multivariate principal-component-analysis (PCA) showed discrete clusters for low (rest-14 km/h) and high (15 - 20 km/h) speeds, and PCA-linear-discriminant-analysis showed 100% classification of 18 - 20 km/h as high speed. Overall, results suggest the possibility of using this non-invasive saliva-based ATR-FTIR method for biochemical assessment during sports exercise and stress tests.

Saliva Preparation Method Exploration for ATR-FTIR Spectroscopy: Towards Bio-fluid Based Disease Diagnosis.

Saliva has garnered a lot of interest as a non-invasive, easy to collect, and biochemical rich sample for attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) based disease diagnosis. Although a large number of studies have explored its potential, the preparation methods used differ greatly. For large scale clinical studies to aid translation into clinics, the collection/processing methodology needs to be standardized. Therefore, in this study, we explored different saliva collection (spitting, method A/cotton soaking, method B) and processing protocols (unprepared, TS; supernatant from the centrifugation, CS; and drying, C) to find which gives the best ATR-FTIR signals. Analysis showed highest proteins, carbohydrates, amino acids, and nucleic acid + proteins/lipids in BTS, BCS, ACS, and BC, respectively. Notably, only BC shows a 1377 cm-1 nucleic acid band that is also uniquely identified in multivariate analysis. We conclude that the collection-processing protocol should be based on a biochemical component that best gives a differential diagnosis.

Raman spectroscopy-multivariate analysis related to morphological surface features on nanomaterials applied for dentin coverage.

Raman spectroscopy and scanning electron microscopy (SEM) were used to investigate the effect of coating materials and acidulated phosphate fluoride gel (APF) treatment on dentin before and after erosion-abrasion cycles. A multi-walled carbon nanotube/graphene oxide hybrid carbon-based material (MWCNTO-GO), nanohydroxyapatite (nHAp), or a combined composite (nHAp/MWCNTO-GO) were used as a coating. Seventy root dentin fragments obtained from 40 bovine teeth were prepared and divided into groups (n = 10): negative control, artificial saliva - C, positive control - APF; nHAp; MWCNTO-GO; APF_nHAp; APF_MWCNTO-GO and APF_nHAp/MWCNTO-GO. All samples were subjected to cycles of demineralization (orange juice, pH ~3.7, room temperature, 1 min) followed by remineralization (saliva, 37 °C, 1 h). The remineralization procedures were followed by tooth brushing (150 strokes). The above cycle was repeated 3×/day for 5 days. The previous APF treatment of dentin allowed a better affinity of nHAp and MWCNTO-GO with the inorganic and organic portion of dentin, respectively. This interaction indicates the formation of a protective layer for the dentin surface and for the collagen giving possible protection against erosion. SEM micrographs illustrated the formation of a protective layer after application of the biomaterials and that it was partially or totally removed after the erosion and abrasion. Raman spectroscopy combined with multivariate analysis could distinguish samples with respect to treatment efficacy. The APF_nHAP/MWCNT-GO composite has shown to be a promising material since it has binding characteristics both to the inorganic and organic portion of the dentin and reduced solubility. Mineral-to-matrix ratio (MMR) parameter analysis confirmed the binding capability of MWCNTO-GO-based materials to dentin.

Adverse effects of respiratory disease medicaments and tooth brushing on teeth: A scanning electron microscopy, X-ray fluorescence and infrared spectroscopy study.

The present study aims to evaluate the effect of brushing with fluoride dentifrice on teeth severely affected by erosion due to respiratory medicaments. Enamel (n = 50) and dentin (n = 50) bovine specimens were prepared and treated with artificial saliva (S-control), acebrofilin hydrochloride (AC), ambroxol hydrochloride (AM), bromhexine hydrochloride (BR), and salbutamol sulfate (SS) and subjected to cycles of demineralization (immersing in 3 mL, 1 min, three times a day at intervals of 1 hr, for 5 days) followed by remineralization (saliva, 37°C, 1 hr). Simulated brushing with fluoridated toothpaste was performed using 810 strokes in a reciprocal-action brushing simulator. Scanning electron microscopy, micro energy dispersive X-ray fluorescence (µ-EDXRF) spectroscopy and attenuated total reflection Fourier transform infrared (ATR FTIR) spectroscopy were then performed. µ-EDXRF images showed extensive erosion after treatment with all medicaments. SEM images showed enamel erosion in order SS > BR > AC = AM > S after brushing and fluoridation. FTIR results were in agreement. In case of dentin, µ-EDXRF measurements showed significant difference in mineral content (percent weight of calcium and phosphate) in SS + brushing + fluoridation treated enamel compared to control, while µ-EDXRF images showed erosive effects in the order SS > AM>BR > AC = S post brushing + fluoridation. SEM images showed erosion in the order SS > AM = BR > AC > S post brushing + fluoridation. Again, FTIR multivariate results were in agreement. Overall, our study shows that proper oral care is critical when taking certain medication. The study also demonstrates the possible use of FTIR for rapid clinical monitoring of tooth erosion in clinics.

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.].

Tendinopathy diagnosis and treatment monitoring using attenuated total reflectance-Fourier transform infrared spectroscopy.

Tendinopathy, an important sports injury afflicting athletes and general public, is associated with huge economic losses. The currently used diagnostic tests are subjective, show moderate sensitivity and specificity; while treatment failures persist despite advances in therapy. This highlights the need for tendinopathy diagnostic and treatment monitoring tools. This study investigates tendon injury, natural healing and effect of treatment using ATR-FTIR complemented with histopathology. Control (C), injured (I) and treated (T) rat tendons were extracted 3, 7, 14 and 28 days post-injury/treatment, representing phases of healing; and subjected to hematoxylin & eosin staining as well as spectroscopy. While C showed no change, I- and T-related histological changes could be clearly observed in stained sections. ATR-FTIR spectra highlighted the biochemical changes within groups. Multivariate analysis could classify C, I and T with 75%; different days between groups with 84%; and different days within group with 65% efficiency. Results suggest that such analysis can not only identify C, I or T but also different phases of healing. Difference between I and T at different time points also suggest change in rate of healing. Further studies may help develop this technique for clinical diagnosis and treatment monitoring in future.

ATR-FTIR spectroscopy and µ-EDXRF spectrometry monitoring of enamel erosion caused by medicaments used in the treatment of respiratory diseases.

Medicaments essential for alleviation of diseases may sometime adversely affect dental health by eroding the enamel, owing to their acidic nature. It is therefore highly desirable to be able to detect these effects quickly and reliably. In this study, we evaluated the erosive capacity of four most commonly prescribed respiratory disease syrup medicaments on enamel using micro-energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). Fifty-five enamel fragments obtained from 30 bovine teeth were treated with artificial saliva (S), acebrofilin hydrochloride (AC), ambroxol hydrochloride (AM), bromhexine hydrochloride (BR), and salbutamol sulfate (SS); by immersing in 3 mL of respective solutions for 1 min, three times a day at intervals of 1 hr, for 5 days. µ-EDXRF analysis of enamel surface did not reveal significant erosion caused by the medications. However, ATR-FTIR showed a detectable shift in the phosphate (PO4 ) antisymmetric stretching mode (ν3 ) at ∼985 cm-1 for AM, BR, and SS, indicating erosion. Multivariate statistical analysis showed that AC, AM, SS, and BR could be classified with 70%, 80%, 100%, and 100% efficiency from S (control), further highlighting the ability of ATR-FTIR to identify degree of erosion. This suggests ATR-FTIR may be used to rapidly and nondestructively investigate erosive effects of medicaments.

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.

Fast monitoring of tooth erosion caused by medicaments used in the treatment of respiratory diseases by ATR-FTIR and µ-EDXRF analysis.

The present study aimed to evaluate the erosive potential of four most commonly prescribed syrup medicaments for respiratory diseases. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy combined with multivariate statistical analysis and micro-energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF) mapping was performed. Fifty-five root dentin fragments obtained from the buccal surface of 30 bovine teeth were prepared and divided into five experimental groups (n = 10): control-artificial saliva (S), acebrofilin hydrochloride (AC), ambroxol hydrochloride (AM), bromhexine hydrochloride (BR), and salbutamol sulfate (SS). The S group was stored only in artificial saliva and the other groups were treated with the medicaments (immersed for 1 min in 3 mL of the medication, three times daily, with 1-h intervals between the immersion cycles, during 5 days, 15 immersion cycles). There were a significant decrease in the Ca and P weight percentages (wt%) for dentin after medication treatments, except for AC (p > 0.05). Mineral content of dentin showed a clear gradation with increasing Ca and P wt% reduction in the order S < AC < AM < BR < SS. SS resulted in a significant increase in Ca/P ratio when compared to the control (p < 0.001). ATR-FTIR combined with multivariate, statistical analysis can quickly and reliably indicate extent of dentin erosion. Considering syrups with high-erosive potential should always follow with proper oral hygiene practices or search for an alternative medications void of such detrimental effects. Regular and prolonged use of these medicaments might bear the risk of causing erosion.