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Lasers and New Technologies in Hair Diseases
Published in Rubina Alves, Ramon Grimalt, Techniques in the Evaluation and Management of Hair Diseases, 2021
Giselle Martins Pinto, Patricia Damasco
It has been long known that red and near-infrared laser light promotes tissue repair, regeneration, and stimulates cellular activity. Endre Mester, a Hungarian physician, in the late 1960s, discovered the biological effects of low-power lasers [1]. Mester had obtained an example of the newly invented ruby laser and commenced a series of experiments on the carcinogenic potential of lasers. However, the ruby laser did not have sufficient power to produce cures in an experimental tumor, Mester found that incisions that had been made healed more rapidly in the laser-treated animals than in controls, and the hair started to grow faster on the irradiated skin area compared to the nonirradiated skin [2]. He named this phenomenon “laser biostimulation” and it later became known as low-level laser therapy (LLLT) [2]. Other names have also been used, such as photobiomodulation, red light therapy, cold laser, and soft laser [3]. The use of the photobiomodulation (PBM) term to replace LLLT was considered in an international consensus for three reasons [4]. First, the words low and level are vague and not accurately definable. Second, the growing realization that other types of light devices such as light-emitting diodes (LEDs) and broadband light sources are currently used for this application. Third, the understanding that many of the applications involved inhibition of biological processes meant that the term modulation was more appropriate [4].
Acquisition and Preservation of Tissue for Microarray Analysis
Published in Brian Leyland-Jones, Pharmacogenetics of Breast Cancer, 2020
Recently, focus has shifted away from whole-tumor microarray analysis to analysis of individual cell types within a tumor. A tumor is composed of a heterogeneous group of cells, malignant cells, premalignant cells, normal parenchymal cells, and supportive cells. This cellular heterogeneity must be taken into account when applying array-based techniques (25). Numerous successful expression-profiling studies have been performed using whole-tumor macromolecular extraction (26–28). These analyses thus incorporate a variety of different cell types. Laser capture microdissection allows one to isolate histologically distinct cell types and perform subsequent analysis. The technique employs an infrared laser in conjunction with light microscopy. Prepared histologic slides are covered with a transfer film. When cells of interest are identified, the laser is activated over the cells. This process causes the cells to attach to the transfer film. The remainder of the sample remains, and the isolated cells can undergo extraction procedures. Notably, this procedure can result in lower yields of cells requiring amplification of nucleic acids for use in microarray experiments (29,30). Laser capture microdissection has the potential to not only improve our understanding of cellular deregulation but also to help determine how other cells within the tumor contribute to the overall tumor phenotype. Immune cells, vascular structures, and normal parenchymal cells within a tumor may contribute significantly to the growth and metastatic potential. Expression analysis of these individual cell types may help elucidate their roles.
Display Technologies
Published in Terry M. Peters, Cristian A. Linte, Ziv Yaniv, Jacqueline Williams, Mixed and Augmented Reality in Medicine, 2018
The simplicity of this kind of setup, however, introduces certain limitations as a compromise. Glossop and wang [58] suggested a laser projector that makes trajectories of the laser appear as lines due to the persistence of vision effect. The images are limited to a certain number of bright monochrome lines or dots and non-raster images. The system also includes an infrared laser for interactive patient digitization. Sasama et al. [59] used two lasers for mere guidance. Each of these lasers creates a plane by means of a moving mirror system. The intersection of both planes is used to guide laparoscopic instruments in two ways. The intersecting lines of the laser on the patient mark the spot of interest, such as an incision point. The laser plane scan can also be used to determine an orientation in space. The system manipulates the two laser planes in such a way that their intersecting line defines the desired orientation. If both lasers are projected in parallel to the instrument, the latter has the correct orientation. The system can only guide instruments to points and lines in space, but it cannot show contours or more complex structures.
Mass spectrometry in the lipid study of cancer
Published in Expert Review of Proteomics, 2021
Md. Mahamodun Nabi, Md. Al Mamun, Ariful Islam, Md. Mahmudul Hasan, A.S.M. Waliullah, Zinat Tamannaa, Tomohito Sato, Tomoaki Kahyo, Mitsutoshi Setou
MALDI is a soft ionization technique that uses a pulsed laser source for irradiation of the matrix-coated sample surface under vacuum conditions. A suitable matrix is required for the proper ionization of lipids. The commonly used matrix are 2,5-dihydroxybenzoic acid, α-cyanocinnamic acid, 9-aminoacridine, and N-(1-naphthyl)ethylenediamine hydrochloride, which have been shown to be useful for the ionization of lipids [60,61]. The sample stage, laser, and mass analyzer are essential parts of the MALDI setup. The laser beam excites the matrix and causes rapid localized heating, which results in the ejection of neutral and charged analyte molecules [36]. The commonly used lasers in MALDI–MSI are Nd: YAG lasers (355 nm) or infrared laser pulses [62]. It is widely used for PLs imaging in cancer [63,64].
Effect of Nd:YAG and Er:YAG laser tooth conditioning on the microleakage of self-adhesive resin cement
Published in Biomaterial Investigations in Dentistry, 2021
Azita Kaviani, Niloofar Khansari Nejad
Nd:YAG laser is a pulsed infrared laser that is highly absorbable in pigmented tissues. This laser can be applied to tooth hard structures to increase resistance to acid attack, remineralize primary caries, alter enamel pits and fissures to prevent caries, disinfect and debride cavities, treat dentin hypersensitivity, sterilize irradiated surfaces, and increase fluoride absorption by the enamel [18]. It might also produce a glass-like appearance on the surface due to enamel and dentin heat liquefaction and re-crystallization [19]. However, the impact of laser irradiation on the surface properties of dental tissue has not been completely elucidated as to whether such irradiation can improve the surface properties of dental tissues. Laboratory studies of microleakage are often performed with the dye penetration test in class V restorations since it is a reliable, clear, and simple procedure [20,21]. Accordingly, this study aimed to compare the microleakage of self-adhesive resin cement with Er:YAG and Nd:YAG laser tooth conditioning. The null hypothesis stated that there would be no differences in microleakage score of self-adhesive resin cement after three different surface conditioning procedures: Er:YAG laser, Nd:YAG laser, nonconditioning.
Laser ablation and topical drug delivery: a review of recent advances
Published in Expert Opinion on Drug Delivery, 2019
Chien-Yu Hsiao, Shih-Chun Yang, Ahmed Alalaiwe, Jia-You Fang
The term laser is an abbreviation of light amplification by stimulated emission of radiation. Laser is a modality producing an intense beam of coherent monochromatic radiation by photon emission stimulation from excited molecules or atoms. The first laser device was developed in 1955 by Dr. Theodore Maiman at Hughes Research Laboratories [7]. The first experience of employing laser for medicinal practice was the use of a ruby laser in tattoo removal by Dr. Leon Goldman [8]. Over the last few decades, lasers have largely been used in dermatology for treating wrinkling, photoaging, hyperpigmentation, actinic keratosis, and scars. The laser is also useful to treat cancers in the presence of photothermal effect. For instance, the near infrared laser in combination with photothermal agents can be applied to deliver anticancer drugs for tumor inhibition [9–11]. The concept of laser-assisted drug transport is based on the reversible ablation or disruption of skin by irradiation to increase skin absorption of the drugs and allow deeper penetration. The first approval of laser-assisted skin delivery was reported by Jacques et al. in 1987 [12]. In that paper, an excimer laser (193 nm) was used to ablate SC from in vitro human skin. The laser fluence at 70 mJ/cm2 produced a 124-fold enhancement of tritiated water permeation, which is similar to that obtained after SC stripping or epidermal removal by mild heat treatment. Since then, some research groups put their efforts into studying drug absorption enhancement by a variety of laser modalities.