This article reviews some of the recent advances in Raman spectroscopy, in areas related to natural tissues and cell biology. It summarizes some of the most widely used peak frequencies and their assignments. The aim of this study is to prepare a database of molecular fingerprints, which will help researchers in defining the chemical structure of the biological tissues introducing most of the important peaks present in the natural tissues. In spite of applying different methods, there seems to be a considerable similarity in defining the peaks of identical areas of the spectra. As a result, it is believed that preparing a unique collection of the frequencies encountered in Raman spectroscopic studies can lead to significant improvements both in the quantity and quality of spectral data and their outcomes. This article is the first review of its kind to provide a precise database on the most important Raman characteristic peak frequencies for researchers aiming to analyze natural tissues by Raman ...

Raman spectroscopy of biological tissues

Exercise Physiology: Energy, Nutrition and Human Performance

The use of low levels of visible or near infrared light for reducing pain, inflammation and edema, promoting healing of wounds, deeper tissues and nerves, and preventing cell death and tissue damage has been known for over forty years since the invention of lasers. Despite many reports of positive findings from experiments conducted in vitro, in animal models and in randomized controlled clinical trials, LLLT remains controversial in mainstream medicine. The biochemical mechanisms underlying the positive effects are incompletely understood, and the complexity of rationally choosing amongst a large number of illumination parameters such as wavelength, fluence, power density, pulse structure and treatment timing has led to the publication of a number of negative studies as well as many positive ones. A biphasic dose response has been frequently observed where low levels of light have a much better effect on stimulating and repairing tissues than higher levels of light. The so-called Arndt-Schulz curve is frequently used to describe this biphasic dose response. This review will cover the molecular and cellular mechanisms in LLLT, and describe some of our recent results in vitro and in vivo that provide scientific explanations for this biphasic dose response.

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Biphasic Dose Response in Low Level Light Therapy

Fluorescence data of replicate samples obtained from different fluorescence spectrometers or by the same spectrometer but with different instrument settings can have great intensity differences. In order to compare such data an intensity calibration must be applied. Here we explain a simple calibration method for fluorescence intensity using only the integrated area of a water Raman peak. By applying this method to data from three different instruments, we show that it is possible to remove instrument-dependent intensity factors, and we present results on a unified scale of Raman units. The method presented is a rapid and simple approach suitable for routine measurements with no need for hazardous chemicals.

Fluorescence Intensity Calibration Using the Raman Scatter Peak of Water

BACKGROUND: Treatment of cancer is increasingly more effective but is associated with short and long term side effects. Oral side effects remain a major source of illness despite the use of a variety of agents to prevent them. One of these side effects is oral mucositis (mouth ulcers). OBJECTIVES: To evaluate the effectiveness of prophylactic agents for oral mucositis in patients with cancer receiving treatment, compared with other potentially active interventions, placebo or no treatment. SEARCH STRATEGY: Electronic searches of Cochrane Oral Health Group and PaPaS Trials Registers (to 16 February 2011), CENTRAL (The Cochrane Library 2011, Issue 1), MEDLINE via OVID (1950 to 16 February 2011), EMBASE via OVID (1980 to 16 February 2011), CINAHL via EBSCO (1980 to 16 February 2011), CANCERLIT via PubMed (1950 to 16 February 2011), OpenSIGLE (1980 to 2005) and LILACS via the Virtual Health Library (1980 to 16 February 2011) were undertaken. Reference lists from relevant articles were searched and the authors of eligible trials were contacted to identify trials and obtain additional information. SELECTION CRITERIA: Randomised controlled trials of interventions to prevent oral mucositis in patients receiving treatment for cancer. DATA COLLECTION AND ANALYSIS: Information regarding methods, participants, interventions, outcome measures, results and risk of bias were independently extracted, in duplicate, by two review authors. Authors were contacted for further details where these were unclear. The Cochrane Collaboration statistical guidelines were followed and risk ratios calculated using random-effects models. MAIN RESULTS: A total of 131 studies with 10,514 randomised participants are now included. Overall only 8% of these studies were assessed as being at low risk of bias. Ten interventions, where there was more than one trial in the meta-analysis, showed some statistically significant evidence of a benefit (albeit sometimes weak) for either preventing or reducing the severity of mucositis, compared to either a placebo or no treatment. These ten interventions were: aloe vera, amifostine, cryotherapy, granulocyte-colony stimulating factor (G-CSF), intravenous glutamine, honey, keratinocyte growth factor, laser, polymixin/tobramycin/amphotericin (PTA) antibiotic pastille/paste and sucralfate. AUTHORS' CONCLUSIONS: Ten interventions were found to have some benefit with regard to preventing or reducing the severity of mucositis associated with cancer treatment. The strength of the evidence was variable and implications for practice include consideration that benefits may be specific for certain cancer types and treatment. There is a need for further well designed, and conducted trials with sufficient numbers of participants to perform subgroup analyses by type of disease and chemotherapeutic agent.

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Interventions for treating oral mucositis for patients with cancer receiving treatment.

Objective: The aim of this study was to investigate if low-level laser therapy (LLLT) can modulate acute inflammation and tumor necrosis factor (TNFα) levels. Background Data: Drug therapy with TNFα-inhibitors has become standard treatment for rheumatoid arthritis, but it is unknown if LLLT can reduce or modulate TNFα levels in inflammatory disorders. Methods: Two controlled animal studies were undertaken, with 35 male Wistar rats randomly divided into five groups each. Rabbit antiserum to ovalbumin was instilled intrabronchially in one of the lobes, followed by the intravenous injection of 10 mg of ovalbumin in 0.5 mL to induce acute lung injury. The first study served to define the time profile of TNFα activity for the first 4 h, while the second study compared three different LLLT doses to a control group and a chlorpromazine group at a timepoint where TNFα activity was increased. The rats in LLLT groups were irradiated within 5 min at the site of injury by a 650-nm Ga-Al-As laser. Results: There was a...

Low-Level Laser Therapy Induces Dose-Dependent Reduction of TNFα Levels in Acute Inflammation

Low-level laser therapy (LLLT) is increasingly being used in the regeneration of soft tissue. In the re- generation of hard tissue, it has already been shown that the biomodulation effect of lasers repairs bones more quickly. We studied the activity in bone cells after LLLT close to the site of the bone injury. The femurs of 48 rats were perforated (24 in the irradiated group and 24 in the control group) and the irradiated group was treated with a GaAlAs laser of 660 nm, 10J/cm 2 of radiant exposure on the 2nd, 4th, 6th and 8th days after surgery (DAS). We carried out histomorphometry analysis of the bone. We found that activity was higher in the irradiated group than in the control group: (a) bone volume at 5 DAS ( p ¼ 0.035); (b) osteoblast surface at 15 DAS ( p ¼ 0.0002); (c) mineral apposition rate at 15 and 25 DAS ( p ¼ 0.0008 and 0.006); (d) osteoclast surface at 5 DAS and 25 DAS ( p ¼ 0.049 and p ¼ 0.0028); and (e) eroded surface ( p ¼ 0.0032). We concluded that LLLT increases the activity in bone cells (resorption and formation) around the site of the repair without changing the bone structure.

Effect of low-power GaAlAs laser (660 nm) on bone structure and cell activity: an experimental animal study.

Background and Objectives

Modern diagnostic methods such as near-infrared Raman spectroscopy (NIRS) allow quantification and evaluation of human atherosclerotic lesions, which can be useful in diagnosing coronary artery disease. The objective of the present study is to obtain feasible diagnostic information to detect atheromatous plaque using NIRS combined with discriminant analysis.



Study Design/Material and Methods

An 830 nm Ti: sapphire laser pumped by an argon laser provides near-infrared excitation. A spectrograph disperses light scattered from arterial tissue and a liquid-nitrogen cooled CCD detects the Raman spectra. A total of 111 arterial fragments were scanned and Raman results were compared with histopathology. Principal components analysis (PCA) and Mahalanobis distance (m-distance) were used to model an algorithm for tissue classification into three categories: non-atherosclerotic (NA), non-calcified (NC), and calcified (C) using Raman spectra. Spectra were randomly separated into training and prospective groups.



Results

It has been found that, for the NA tissue, the algorithm has sensitivity of 84 and 78% and specificity of 91 and 93% for training and prospective groups, respectively. For the NC tissue the algorithm has sensitivity of 88 and 90% and specificity of 88 and 83%. For the C tissue both sensitivity and specificity were maximum, 100%.



Conclusions

An algorithm using PCA and discriminant analysis based on m-distance has been developed and successfully applied to diagnose coronary artery disease by NIRS obtaining good sensitivity and specificity for each tissue category. Lasers Surg. Med. 30:290–297, 2002. © 2002 Wiley-Liss, Inc.

Correlation between near-infrared Raman spectroscopy and the histopathological analysis of atherosclerosis in human coronary arteries.

Current forensic methods for detecting and identifying cocaine and other drugs of abuse are destructive, so evidence cannot be re-analyzed. Raman spectroscopy, based on inelastic light scattering, allows for rapid, inexpensive and nondestructive analysis in forensic science. This review presents the state-of-the-art use of Raman spectroscopy as a confirmatory method for the identification of cocaine and other drugs of abuse in seized samples, including hidden compounds in legal materials such as beverages and clothes, among others, used for trafficking. Quantitative Raman spectroscopy is used to determine the actual drug concentrations in street cocaine and crack rocks and to identify possible adulterants in these samples for forensic toxicology and criminalistics. Finally, recent developments in Raman spectrometers (portable instruments and new excitation wavelengths) and advancements in data analysis offer exciting opportunities for new applications of Raman spectroscopy in the identification and quantification of drugs of abuse, including investigations conducted immediately at the scene of a crime. Copyright © 2016 JohnWiley & Sons, Ltd.

Raman spectroscopy in forensic analysis: identification of cocaine and other illegal drugs of abuse

This work presents the development of a method for rapid bacterial identification based on the autofluorescence spectrum It was demonstrated differences in the autofluorescence spectrum in three bacterial species and the subsequent separation, through the Principal Components Analysis (PCA) technique, in groups with high likeness, that could identify the bacteria in less than 10 min Fluorescence spectra of 60 samples of 3 different bacterial species (Escherichia coli, EC, Enterococcus faecalis, EF and Staphylococcus aureus, SA), previously identified by automated equipment Mini API, were collected in 10 excitation wavelengths from 330 to 510 nm The PCA technique applied to the fluorescence spectra showed that bacteria species could be identified with sensitivity and specificity higher than 90% according to differences that occur within the spectra with excitation of 410 nm and 430 nm This work presented a method of bacterial identification of three more frequent and more clinically significant species based on the autofluorescence spectra in the excitation wavelengths of 410 and 430 nm and the classification of the spectra in three groups using PCA The results demonstrated that the bacterial identification is very efficient with such methodology The proposed method is rapid, ease to perform and low cost compared to standard methods

M.T.T. Pacheco

Papers

Low-Level Laser Therapy Induces Dose-Dependent Reduction of TNFα Levels in Acute Inflammation

Effect of low-power GaAlAs laser (660 nm) on bone structure and cell activity: an experimental animal study.

Correlation between near-infrared Raman spectroscopy and the histopathological analysis of atherosclerosis in human coronary arteries.

Raman spectroscopy in forensic analysis: identification of cocaine and other illegal drugs of abuse

Rapid Identification of Bacterial Species by Fluorescence Spectroscopy and Classification Through Principal Components Analysis