As low fluence Q-switched Nd:YAG laser treatment for melasma, Laser Toning, is becoming popular, the numbers of cases with adverse reactions are rapidly increasing these days. These cases include melasma darkening and punctate leukoderma formation after finishing treatment. Laser Toning performed at ordinary clinics should be prohibited or suspended until its effectiveness and safety are authorized by some academic organizations.

Athletes train for important games or competitions. Although some strategies have been used for conditioning the athletes, currently, the use of laser therapy is uncommon. This paper discusses the comparative effect of different timing of irradiation during laser therapy and their mechanisms on muscle fatigue

Laser vaporization of the prostate is expected as a less invasive treatment by photothermal effect for benign prostatic hyperplasia (BPH). In order to develop safer and more effective laser vaporization of the prostate, it is essential to set optimal irradiation parameters based on quantitative evaluation of temperature distribution and thermally denatured depth in prostate tissue. Therefore, a simulation model with light propagation and heat transfer calculation was constructed, and the vaporized and thermally denatured depths were estimated by the simulation model. The results of the simulation were compared with those of an ex vivo experiment and clinical trial. As the result, the vaporized depth strongly depended on the distance between the optical fiber and the prostate tissue, and it was suggested that contact laser irradiation could vaporize the prostate tissue most effectively. Additionally, it was suggested by analyzing thermally denatured depth comprehensively that laser irradiation at the distance of 3 mm between the optical fiber and the prostate tissue was useful for hemostasis. This study enabled quantitative and reproducible analysis of laser vaporization for BPH and will play a role in clarification of safety and efficacy of this treatment.

The discovery of channelrhodopsin (ChR) molecules opened the door to new research field of optogenetics allowing us to optically control biological functions. ChR is the first light-gated cation channels found in flagellated green algae, functioning as a sensory photoreceptor for optimal light environment. By various technologies such as spectroscopy, electrophysiology, structural analysis and molecular dynamics, the molecular function of ChR has been emerged to explain the channel activation and ion conduction, which are induced by chromophore photo-isomerization and structural changes of the molecule. Furthermore these studies would enable us to engineer new ChRs which have more appropriate properties for optogenetics applications.

Optogenetics has been rapidly grown up since a start of pioneering works utilizing channelrhodopsin to generate action potentials of nerve cells in light dependent manner. Elucidation of molecular mechansims of microbial rhodopsins including channelrhodopsin gives guides for rational designs toward their functional alteration by genetic engineering. In this review article, the light-induced infrared difference spectroscopy is introduced as a powerful technique for investigation of light-responsive mechanisms of microbial rhodopsins.

Microbial rhodopsins are photoreceptive membrane proteins which transport various ions upon light absorption. Particularly, light-driven ion pump rhodopsins unidirectionally transport ions against concentration gradient. Whereas most ubiquitous pumps are outward H⁺ pump, inward Cl^- and outward Na⁺ pumps are also known. Here, the ion transport mechanisms of ion pump rhodopsins are reviewed.

Since its creation, optogenetics has mostly been applied to controlling neuronal activity. However, the idea of controlling cell activity with light can be applied to any other cell type as well. As a multicellular organism, we are able to perform coherent activity and maintain individuality by signals that circulates among multiple cells and organs. In this paper, I will introduce an example of the use of optogenetics outside of the conventional neuroscience, where we chose to optically control the activity of glial cells. Possible future use of optogenetics in system biology will also be discussed.

Optogenetics is a powerful tool to manipulate neuronal activities. This review article describes the history of the neuroscience at first and then the author comments how this innovative technology contributes to the progress in the current neuroscience field. Lastly the author gives his opinion regarding the possible application of optogenetics in the psychiatry.

The optogenetics that combines optical technology and genetic engineering techniques, have been reported to control the cellular function by light. In this review, we summarize the prospects for the therapeutic applications of optogenetics using the channelrhodopsin 2, which is a typical light receptor, and our recent research results.

Pharmaceuticals and Medical Devices Agency（PMDA） is summarizing the actual use and basic thoughts about medical laser through the discussion with academia and industry. This activity is expected to promote the novel medical laser development as well as to supply the medical laser in a suitable manner. This article introduces the background and the contents of this PMDA’s activity.

Recently medical laser devices have become to be the clinically-essential equipment for proper diagnosis and treatments. New laser equipment and peripheral technologies have been developed since 1980s, and currently the medical laser devices have many functions for various clinical indications. We, the users of medical laser devices, are demanded to enhance the knowledge and skills concerning about new laser technologies. And more, the users should recognize that the daily checking of laser devices, such as the output of laser beam, the irradiation pattern, the optical plane and etc., is needed for the reproducibility of laser treatment and the laser safety. We have to intensify the activity to raise awareness for importance of the scheduled checking of laser devices.

This document explains the challenges faced by the industry at the point of our presentation at the 35^th Annual Meeting of Japan Society for Laser Surgery and Medicine, introducing the objectives, history and current activities of Japan Medical Laser Association as well as its path to issuance of “Notification of non-necessity of clinical test.” Also mentioned here is our past approach and future direction toward the said Notification, on which PMDA recently announced its intention of review.

The pulsed-dye laser has been a first choice treatment of a port-wine stain (PWS) since a quarter century ago, and the long-pulsed dye laser with a cold air cooling system is seen as the gold standard treatment for a PWS currently. Selectively the laser irradiation damaged an ectatic blood vessels of PWS without scarring, but the dye laser were limited to a depth and diameter of ectatic blood vessels. We observed significant redarkening of a PWS at long-term follow up after the dye laser therapy. Finally practical problems in dye laser treatment of PWS were discussed.

Syringoma is benign multiple tiny tumor that occurs mainly on periorbital site or on the whole body. Although pulsed carbon dioxide laser has been established as the only modality to remove it, immediate erosion, prolonged erythema and post hyperpigmentation as well as the risk of scar is the problem to be solved. Fractional carbon dioxide laser might be an alternative to the conventional deep ablation to reduce this downtime. The balance of the effect of ablation and thermal coagulation should be considered dependent on the pathology.

In almost all countries are changing into aging countries, pigmented lesions on the face are main factor which damages quality of life (QOL) seriously in a cosmetic point of view. Seborreic keratosis is most popular pigmented elevated lesion in aged person faces. To cure the lesions makes them happy, and increases their QOL. I introduce the treatment using cabon dioxide laser for seborrheic keratosis of the aged personsin this paper.