In order to evaluate the relationship between reactive oxygen species (ROS) production from human neutrophils and the health of the organism, we developed a new technique and apparatus to measure ROS, and studied the relationship between ROS production and many kinds of environmental factors, such as the circadian rhythm, various degrees of exercise loading and training, diet, alcohol, smoking, and other environmental factors. ROS production and serum opsonic activity did not significantly change at levels of up to 50-60% of VO2max, as advocated by the Japanese Ministry of Health, Labour and Welfare, but in the case of exercise overloading to more than 65% VO2max, ROS production increased. On the other hand, when neutrophils were exposed to environmental factors, e.g., ethanol, minerals, interferon, laser, ultraviolet light and so on, at a low density, ROS production from neutrophils was only slightly enhanced. However, when neutrophils were exposed to the same environmental factors at an excessive density, ROS production significantly decreased. Given that small increases in ROS production from neutrophils are beneficial to the organism, as many researchers have reported, ROS production at low density exposure to environmental factors may increase the autoimmunocompetency of the organism, in other words, it is good for the health. Furthermore, ROS production and serum opsonic activity showed an inverse relationship in many kinds of environment, indicating a mutual compensatory mechanism to maintain the homeostasis of the autoimmune system.
Inflammation of many different aetiologies is a condition affecting almost 100% of all patients presenting at dental clinics, and the complete management of inflammation is often extremely important before any orthodontic surgery can be carried out. The lymphatic system is one of the body’s main lines of defence against inflammation, with the lymph nodes playing an extremely major role. laser therapy, or LLLT, has become much more common in dental offices, and is associated with pain attenuation, wound healing and anti-inflammatory properties. The last of these is mediated amongst others by the effect of LLLT on the lymphatic system, which has been shown to enhance lymphatic drainage concomitantly with increasing local blood flow to the treated area. Infected areas and those with viral contamination have been suggested as contraindications for laser therapy. The possibility of treating these difficult-to-manage entities through laser therapy-accelerated drainage of the affected lymphatics offers another approach. Although lymphatic drainage is frequently used in the clinical setting, its application in dentistry is less common than it should be. An illustrated review of the lymphatic system of the head and neck is presented, with relevance to the use of infrared diode laser therapy in inducing lymphatic drainage in the management of inflammation associated with acute infectious processes such as pericoronitis, endodontic abscesses, alveolitis and herpes. A case report is presented illustrating the success of this therapeutic approach for labial herpes simplex. Infrared diode laser therapy-mediated lymphatic drainage offers an interesting and efficacious approach in the management of infectious and contaminated areas, without actually irradiating the areas themselves.
There have been many reports on the applications of low reactive level laser therapy (LLLT) for pain attenuation or pain removal. Our group has reported previously on the effects of in vitro low level laser irradiation (LLLI) particularly on the human neutrophil function using luminol-dependent chemiluminescence (LmCL) for measurement of reactive oxygen species (ROS) production from human neutrophils. However, the change in production by LLLI for each ROS e.g. superoxide, hydroxyl radicals, hydrogen peroxide, singlet oxygen, hypochlorite and so on are however not yet fully understood. In this study, we used luminol-dependent and lucigenin-dependent chemiluminescence (LmCL and LgCL, respectively) to measure the effects of LLLI on the ROS-production process of human neutrophils. Two soluble action stimuli, N-formyl-Met-Leu-Phe (fMLP) and phorbol myristate acetate (PMA) were used to avoid the possible influence of lag-time from recognition to uptake of particles at ROS production. When fMLP was used as the stimulus, the maximum intensity of the chemiluminescence response in LmCL increased but in LgCL it decreased following LLLI. When PMA was used as a stimulus, the times to reach the maximum intensity of the chemiluminescence response of LmCL and LgCL were shortened by LLLI but there was no effect on the maximum intensity of the chemiluminescence response of both. These results suggest that LLLI enhances the ROS production capability, and activates the conversion from superoxide to singlet oxygen and hypochlorite.
Sumo wrestling is a very powerful and competitive contact sport played by extremely fit and highly trained competitors. Due to the extremely competitive nature of the sport and the required training, injuries are common both during training and the actual competition. Long-term lay-up of the competitor has to be avoided in order to maintain the level of muscle tone and mental concentration generated by the grueling training, so postinjury recovery time is kept to a minimum. A noninvasive therapy is therefore required, and the recent interest in the successful application of low level laser therapy (LLLT) in pain attenuation for a large number of pain types suggested that it might offer a new tool for sumo-related injuries. The current trial, with ten sports university sumo wrestlers, examined the effect of LLLT on injuries of the knee (five subjects) and foot (five subjects), using laser speckle flowmetry to assess the possible increase in superficial blood flow which has been associated with both pain attenuation and accelerated wound healing. An 830 nm 60 mW GaAlAs diode LLLT system was applied on one point for 5 min (approximately 15 J/cm2), and laser speckle flowmetry was performed before, during, immediately after, at 30 min and 60 min after irradiation. Decreased blood flow was seen intrairradiation, but an increase, significant in 7 of the 10 subjects was seen immediately postirradiation. This was maintained at significantly elevated levels in 4 subjects, while the remaining six decreased slightly, but in all ten subjects elevated levels of superficial blood flow were seen at one hour postirradiation, compared with preirradiation. LLLT is noninvasive, easy to apply, well tolerated and adverse side effect free. It is suggested that, following further trials to elucidate dosimetry and possible wavelength specificity, LLLT may well offer an exciting new tool to the sports clinician treating injured sumo wrestlers.
Laser surgery is now an accepted reality. What has not yet been completely accepted, and remains at best only partly understood is the athermal reaction which accompanies with very few exceptions all photothermal reactions associated with the surgical laser. One particular field where this athermal reaction plays a role at least as important as the thermal reactions is in the application of nonablative light sources in the rejuvenation of photoaged skin. This field is expanding rapidly, but the photobiology behind the processes by which a particular type and dose of light can repair damage (which was actually also caused in the first place by light) is imperfectly understood. Although the main concept of nonablative skin rejuvenation is centred on the creation of a controlled zone of delivered thermal damage (DTD) in the upper dermis under a cooled epidermis, the incident light energy, in the form of photons, does not simply stop at the DTD zone but continues on into the surrounding dermal tissue, mediating athermal photoreactions in the periphery of that thermal effect. These athermal reactions, at a cellular and subcellular level, contribute a great deal to the modulation of the wound healing process instigated by the DTD to produce the final hoped-for results. This article examines the range of athermal photoreactions which occur simultaneously with the thermally-mediated effects in nonablative skin rejuvenation, to a great extent in laser ablative resurfacing and indeed in any surgical application of the laser, and attempts to show the importance of these photobioreactions in achieving good clinical results. This first part of the series may well appear as ‘old hat’ to experienced users of lasers and light sources, but we feel it is important to start from the basics, rather than having to return to them to try and discover why tissue has failed to react to the incident light in the expected manner, and a possibly unhappy patient as a result. A thorough understanding of the basic properties of light and its parameters is extremely important when trying to appreciate the complexities of light-tissue interaction. Without this understanding, moreover, no-one should be using any form of light source on patients.