Rheumatoid arthritis is a systemic inflammatory disease of unknown causes and a new methods to identify it in early
stages are needed. The main purpose of this work is the biochemical differentiation of sera between normal and RA
patients, through the establishment of a statistical method that can be appropriately used for serological analysis. The
human sera from 39 healthy donors and 39 rheumatics donors were collected and analyzed by Fourier Transform
Infrared Spectroscopy. The results show significant spectral variations with p<0.05 in regions corresponding to protein,
lipids and immunoglobulins. The technique of latex particles, coated with human IgG and monoclonal anti-CRP by
indirect agglutination known as FR and CRP, was performed to confirm possible false-negative results within the groups,
facilitating the statistical interpretation and validation of the technique.
Rheumatoid Arthritis is a systemic chronic inflammatory disease, recurrent and systemic, initiated by
autoantibodies and maintained by inflammatory mechanisms cellular applicants. The evaluation of this
disease to promote early diagnosis, need an associations of many tools, such as clinical, physical
examination and thorough medical history. However, there is no satisfactory consensus due to its
complexity. In the present work, confocal Raman spectroscopy was used to evaluate the biochemical
composition of human serum of 40 volunteers, 24 patients with rheumatoid arthritis presenting clinical
signs and symptoms, and 16 healthy donors. The technique of latex agglutination for the polystyrene
covered with human immunoglobulin G and PCR (protein c-reactive) was performed for confirmation
of possible false-negative results within the groups, facilitating the statistical interpretation and
validation of the technique. This study aimed to verify the changes for the characteristics Raman peaks
of biomolecules such as immunoglobulins amides and protein. The results were highly significant with a
good separation between groups mentioned. The discriminant analysis was performed through the
principal components and correctly identified 92% of the donors. Based on these results, we observed
the behavior of arthritis autoimmune, evident in certain spectral regions that characterize the
serological differences between the groups.
The effects of laser etching, decontamination, and storage treatments on dentin components were studied using Fourier transform (FT)-Raman spectroscopy. Thirty bovine incisors were prepared to expose the dentin surface and then divided in two main groups based upon the decontamination process and storage procedure: autoclaved (group A, n=15) or stored in thymol aqueous solution (group B, n=15). The surfaces of the dentin slices were schematically divided into four areas, with each one corresponding to a treatment subgroup. The specimens were either etched with phosphoric acid (control subgroup) or irradiated with erbium-doped yttrium-aluminum-garnet (Er:YAG) laser (subgroups: I-80 mJ, II-120 mJ, and III-180 mJ, and total energy of 12 J). Samples were analyzed by FT-Raman spectroscopy; we collected three spectra for each area (before and after treatment). The integrated areas of five Raman peaks were calculated to yield average spectra. The areas of the peaks associated with phosphate content (P<0.001), type I collagen, and organic C-H bonds (P<0.05) were reduced significantly in group A (control). Analyses of samples irradiated with reduced laser energies did not show significant changes in the dentin components. These results suggest that thymol storage treatment is advised for in vitro study; furthermore, 12 J of Er:YAG laser energy does not affect dentin components.
KEYWORDS: Raman spectroscopy, Tissues, Tumors, Breast cancer, Mammary gland, In vivo imaging, Tumor growth modeling, Animal model studies, Tissue optics, Breast
Raman spectroscopy has been well established as a powerful method for studying biological tissues and
diagnosing diseases. In this study we have developed a breast cancer animal model and collected in
vivo Raman spectra of mammary glands of 27 Sprague-Dawley female rats treated with DMBA and 5
non-treated used as control group. A dispersive Raman spectrometer with a @785 nm laser excitation
coupled a fiber optic probe and a CCD detector was used to obtain the spectra. The obtained in vivo
transcutaneous Raman spectra have shown important differences between normal and abnormal tissues
when acquired from one side to the other side of the lesion.
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.
FT-Raman spectroscopy was employed to access the biochemical alterations occurring on the degenerative process of
the rotator cuff supraspinatus tendons. The spectral characteristic variations in the 351 spectra of samples of 39 patients
were identified with the help of Principal Components Analysis. The main variations occurred in the 840-911; 1022-
1218; 1257; 1270; 1300; 1452; 1663; and 1751 cm-1 regions corresponding to the vibrational bands of proline,
hydroxiproline, lipids, nucleic acids, carbohydrates, collagen, and elastin. These alterations are compatible with the
pathology alterations reported on the literature. Scattering plots of PC 4 vs PC 2 and PC 3 vs PC 2 contrasted with
histopathological analysis has enabled the spectral classification of the data into normal and degenerated groups of
tendons. By depicting empiric lines the estimated sensibility and specificity were 39,6 % and 97,8 %, respectively for PC
4 vs PC 2 and 36,0 % and 100 %, respectively for PC 3 vs PC 2. These results indicate that Raman spectroscopy can be
used to probe the general tendon quality and could be applied as co adjuvant element in the usual arthroscopy surgery
apparatus to guide the procedure and possibly infer about the probability of rerupture.
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