Water-Filtered Infrared A Irradiation in Combination with Visible Light Inhibits Acute Chlamydial Infection

New therapeutic strategies are needed to overcome drawbacks in treatment of infections with intracellular bacteria. Chlamydiaceae are Gram-negative bacteria implicated in acute and chronic diseases such as abortion in animals and trachoma in humans. Water-filtered infrared A (wIRA) is short wavelength infrared radiation with a spectrum ranging from 780 to 1400 nm. In clinical settings, wIRA alone and in combination with visible light (VIS) has proven its efficacy in acute and chronic wound healing processes. This is the first study to demonstrate that wIRA irradiation combined with VIS (wIRA/VIS) diminishes recovery of infectious elementary bodies (EBs) of both intra- and extracellular Chlamydia (C.) in two different cell lines (Vero, HeLa) regardless of the chlamydial strain (C. pecorum, C. trachomatis serovar E) as shown by indirect immunofluorescence and titration by subpassage. Moreover, a single exposure to wIRA/VIS at 40 hours post infection (hpi) led to a significant reduction of C. pecorum inclusion frequency in Vero cells and C. trachomatis in HeLa cells, respectively. A triple dose of irradiation (24, 36, 40 hpi) during the course of C. trachomatis infection further reduced chlamydial inclusion frequency in HeLa cells without inducing the chlamydial persistence/stress response, as ascertained by electron microscopy. Irradiation of host cells (HeLa, Vero) neither affected cell viability nor induced any molecular markers of cytotoxicity as investigated by Alamar blue assay and Western blot analysis. Chlamydial infection, irradiation, and the combination of both showed a similar release pattern of a subset of pro-inflammatory cytokines (MIF/GIF, Serpin E1, RANTES, IL-6, IL-8) and chemokines (IL-16, IP-10, ENA-78, MIG, MIP-1α/β) from host cells. Initial investigation into the mechanism indicated possible thermal effects on Chlamydia due to irradiation. In summary, we demonstrate a non-chemical reduction of chlamydial infection using the combination of water-filtered infrared A and visible light.     

UV-induced free radicals in the skin detected by ESR spectroscopy and imaging using nitroxides

Reactive free radicals and reactive oxygen species (ROS) induced by ultraviolet irradiation in human skin are strongly involved in the occurrence of skin damages like aging and cancer. In the present work an ex vivo method for the detection of free radicals/ROS in human skin biopsies during UV irradiation is presented. This method is based on the Electron Spin Resonance (ESR) spectroscopy and imaging and uses the radical trapping properties of nitroxides. The nitroxides 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO), 3-Carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (PCM), and 3-Carboxy-2,2,5,5-tetramethylpyrrolidine-1-oxyl (PCA), were investigated for their applicability of trapping reactive free radicals and reactive oxygen species in skin during UV irradiation. As a result of the trapping process the nitroxides were reduced to the EPR silent hydroxylamins. The reduction rate of TEMPO was due to both the UV radiation and the enzymatic activity of the skin. The nitroxides PCM and PCA are sufficiently stable in the skin and are solely reduced by UV-generated free radicals/ROS. The nitroxide PCA was used for imaging the spatial distribution of UV-generated free radicals/ROS. As a result of the homogeneous distribution of PCA in the skin, it was possible to estimate the penetration of UVA and UVB irradiation: The UV irradiation decreased the PCA intensity corresponding to its irradiance and penetration into the skin. This reduction was shown to be caused mainly by UVA radiation (320-400 nm).     

The role of melanocytes in protection against photooxidative stress Krystyna Stepień

Excessive exposure to solar ultraviolet radiation is an essential etiological factor for skin cancer. UV radiation, directly or indirectly through the generation of reactive oxygen species (ROS), causes damage to DNA, proteins and lipids, and induces inflammation and immunosuppression. Cutaneous pigmentation afforded by melanocytes is the main photoprotective mechanism in human skin. In response to UV, melanocytes produce melanin pigments and transfer them to adjacent keratinocytes. This review describes: (i) the photoprotective action of melanin; (ii) the regulation of UV-induced melanogenesis and the role of p53 in this process; (iii) the relation between melanogenic and antioxidant activities in melanocytes. The possible involvement of UV-induced ROS in the stimulation of melanin synthesis is also discussed.     

Wavelength,dose, skin type and skin model related radical formation in skin

The exposure to sun radiation is indispensable to our health; however, a long-term and high exposure could lead to cell damage, erythema, premature skin aging, and promotion of skin tumors. An underlying pathomechanism is the formation of free radicals which may induce oxidative stress at elevated concentrations. Different skin models, such as porcine-, murine-, human- ex vivo skin, reconstructed human skin (RHS) and human skin in vivo, were investigated during and after irradiation using X- and L-band EPR spectroscopy within different spectral regions (UVC to NIR). The amount of radical formation was quantified with the spin probe PCA and the radical types were measured ex vivo with the spin trap DMPO. The radiation dose influences the types of radicals formed in the skin. While reactive oxygen species (ROS) are always pronounced at low doses, there is an increase in lipid oxygen species (LOS) at high doses. Furthermore, the radical types arise independent from the irradiation wavelength, whereas the general amount of radical formation differs with the irradiation wavelength. Heat pre-stressed porcine skin already starts with higher LOS values. Thus, the radical type ratio might be an indicator of stress and the reversal of ROS/LOS constitutes the point where positive stress turns into negative stress.Compared to light skin types, darker types produce less radicals in the ultraviolet, similar amounts in the visible and higher ones in the infrared spectral region, rendering skin type-specific sun protection a necessity.     

Irradiation of Cells with Ultraviolet-A (320-400 nm) in the Presence of Cell Culture Medium Elicits Biological Effects Due to Extracellular Generation of Hydrogen Peroxide

Biological effects of ultraviolet A (UVA) irradiation have been ascribed to the photochemical generation of singlet oxygen. Not all effects described in the literature, however, are explicable solely by the generation of singlet oxygen, but rather resemble effects elicited by hydrogen peroxide (H 2 O 2 ). Here, we show that when cells are kept in cell culture media during exposure to UVA, stress kinases, including ERK 1 and ERK 2 as well as Akt (protein kinase B), are activated, whereas there is no or only minor activation when cells are kept in phosphate-buffered saline during irradiation. Indeed, the exposure of cell culture media to UVA (30 J/cm 2 ) results in the generation of significant amounts of H 2 O 2 , with concentrations of about 100 &#119 M. H 2 O 2 concentrations are at least three-fold higher in HEPES-buffered culture media after UVA irradiation. From experiments with solutions of riboflavin, tryptophan or HEPES, as well as combinations thereof, it is concluded that riboflavin mediates the photooxidation of either tryptophan or HEPES, resulting in the generation of H 2 O 2 . Thus, if signaling effects of UVA radiation are to be investigated in cell culture systems, riboflavin and HEPES/tryptophan should be avoided during irradiation because of artificial H 2 O 2 generation. It should be taken into account, however, that in vivo tryptophan and riboflavin might play an important role in the generation of reactive oxygen species by UVA as both substances are abundant in living tissues.     

UVA and endogenous photosensitizers--the detection of singlet oxygen by its luminescence

UVA irradiation (320-400 nm) comprises about 95 percent of incident midday solar ultraviolet irradiation. It penetrates skin much deeper than UVB irradiation. The absorption of UVA irradiation in endogenous chromophores frequently leads to the generation of reactive oxygen species such as singlet oxygen ((1)O(2)). (1)O(2) is an important biochemical intermediate in multiple biological processes. Beside other procedures, the direct detection of (1)O(2) by its luminescence is a powerful tool that helps to understand the generation of (1)O(2) during UVA exposure in solution, in vitro and in vivo. This article describes the endogenous photosensitizers, their ability to generate (1)O(2) under UVA irradiation, and the detection technology to visualize the action of (1)O(2).     

Irradiation of cells with ultraviolet-A (320-400 nm) in the presence of cell culture medium elicits biological effects due to extracellular generation of hydrogen peroxide

Biological effects of ultraviolet A (UVA) irradiation have been ascribed to the photochemical generation of singlet oxygen. Not all effects described in the literature, however, are explicable solely by the generation of singlet oxygen, but rather resemble effects elicited by hydrogen peroxide (H 2 O 2 ). Here, we show that when cells are kept in cell culture media during exposure to UVA, stress kinases, including ERK 1 and ERK 2 as well as Akt (protein kinase B), are activated, whereas there is no or only minor activation when cells are kept in phosphate-buffered saline during irradiation. Indeed, the exposure of cell culture media to UVA (30 J/cm 2 ) results in the generation of significant amounts of H 2 O 2 , with concentrations of about 100 μM. H 2 O 2 concentrations are at least three-fold higher in HEPES-buffered culture media after UVA irradiation. From experiments with solutions of riboflavin, tryptophan or HEPES, as well as combinations thereof, it is concluded that riboflavin mediates the photooxidation of either tryptophan or HEPES, resulting in the generation of H 2 O 2 . Thus, if signaling effects of UVA radiation are to be investigated in cell culture systems, riboflavin and HEPES/tryptophan should be avoided during irradiation because of artificial H 2 O 2 generation. It should be taken into account, however, that in vivo tryptophan and riboflavin might play an important role in the generation of reactive oxygen species by UVA as both substances are abundant in living tissues.     

Singlet oxygen mediates the UVA-induced generation of the photoaging-associated mitochondrial common deletion.

Mutations of mitochondrial (mt) DNA accumulate during normal aging. The most frequent mutation is a 4,977-base pair deletion also called the common deletion, which is increased in photoaged skin. Oxidative stress may play a major role in the generation of large scale mtDNA deletions, but direct proof for this has been elusive. We therefore assessed whether the common deletion can be generated in vitro through UV irradiation and whether reactive oxygen species are involved in this process. Normal human fibroblasts were repetitively exposed to sublethal doses of UVA radiation and assayed for the common deletion employing a semiquantitative polymerase chain reaction technique. There was a time/dose-dependent generation of the common deletion, attributable to the generation of singlet oxygen, since the common deletion was diminished when irradiating in the presence of singlet oxygen quenchers, but increased when enhancing singlet oxygen half-life by deuterium oxide. The induction of the common deletion by UVA irradiation was mimicked by treatment of unirradiated cells with singlet oxygen produced by the thermodecomposition of an endoperoxide. These studies provide evidence for the involvement of reactive oxygen species in the generation of aging-associated mtDNA lesions in human cells and indicate a previously unrecognized role of singlet oxygen in photoaging of human skin.     

Natural phenolics in the prevention of UV-induced skin damage. A review

UV skin exposure induces extensive generation of reactive oxygen species (ROS). These can react with DNA, proteins, fatty acids and saccharides causing oxidative damage. Such injuries result in a number of harmful effects: disturbed cell metabolism, morphological and ultrastructural changes, attack on the regulation pathways and, alterations in the differentiation, proliferation and apoptosis of skin cells. These processes can lead to photoaging and skin cancer development. One approach to protecting human skin against the harmful effects of UV irradiation is to use antioxidants as photoprotectives. In recent years naturally occurring herbal compounds such as phenolic acids, flavonoids, and high molecular weight polyphenols have gained considerable attention as beneficial protective agents. In this review, we strive to summarize the findings of studies performed to date, regarding the photoprotective effects of plant phenolics on the skin damage induced by UV radiation.     

Generation of reactive oxygen species in water under exposure of visible or infrared irradiation at absorption band of molecular oxygen

It is found that in bidistilled water saturated with oxygen hydrogen peroxide and hydroxyl radicals are formed under the influence of visible and infrared radiation in the absorption bands of molecular oxygen. Formation of reactive oxygen species (ROS) occurs under the influence of both solar and artificial light sourses, including the coherent laser irradiation. The oxygen effect, i.e. the impact of dissolved oxygen concentration on production of hydrogen peroxide induced by light, is detected. It is shown that the visible and infrared radiation in the absorption bands of molecular oxygen leads to the formation of 8-oxoguanine in DNA in vitro. Physicochemical mechanisms of ROS formation in water when exposed to visible and infrared light are studied, and the involvement of singlet oxygen and superoxide anion radicals in this process is shown.     

Generation of reactive oxygen species in water under exposure to visible or infrared irradiation at absorption bands of molecular oxygen

It is found that in bidistilled water saturated with oxygen, hydrogen peroxide and hydroxyl radicals are formed under the influence of visible and infrared radiation in the absorption bands of molecular oxygen. Formation of reactive oxygen species (ROS) occurs under the influence of both solar and artificial light sources, including the coherent laser irradiation. The oxygen effect, i.e. the impact of dissolved oxygen concentration on production of hydrogen peroxide induced by light, is detected. It is shown that the visible and infrared radiation in the absorption bands of molecular oxygen leads to the formation of 8-oxoguanine in DNA in vitro. Physicochemical mechanisms of ROS formation in water when exposed to visible and infrared light are studied, and the involvement of singlet oxygen and superoxide anion radicals in this process is shown.     

Investigating the role of melanin in UVA/UVB- and hydrogen peroxide-induced cellular and mitochondrial ROS production and mitochondrial DNA damage in human melanoma cells

Skin cancer incidence is dramatically increasing worldwide, with exposure to ultraviolet radiation (UVR) a predominant factor. The UVA component initiates oxidative stress in human skin, although its exact role in the initiation of skin cancer, particularly malignant melanoma, remains unclear and is controversial because there is evidence for a melanin-dependent mechanism in UVA-linked melanoma studies. Nonpigmented (CHL-1, A375), moderately pigmented (FM55, SKmel23), and highly pigmented (FM94, hyperpigmented FM55) human melanoma cell lines have been used to investigate UVA-induced production of reactive oxygen species using FACS analysis, at both the cellular (dihydrorhodamine-123) and the mitochondrial (MitoSOX) level, where most cellular stress is generated. For the first time, downstream mtDNA damage (utilizing a quantitative long-PCR assay) has been investigated. Using UVA, UVB, and H(2)O(2) as cellular stressors, we have explored the dual roles of melanin as a photoprotector and photosensitizer. The presence of melanin has no influence over cellular oxidative stress generation, whereas, in contrast, melanin protects against mitochondrial superoxide generation and mtDNA damage (one-way ANOVA with post hoc Tukey's analysis, P<0.001). We show that if melanin binds directly to DNA, it acts as a direct photosensitizer of mtDNA damage during UVA irradiation (P<0.001), providing evidence for the dual roles of melanin.     

The formation of DNA single-strand breaks and alkali-labile sites in human blood lymphocytes exposed to 365-nm UVA radiation

The potency of UVA radiation, representing 90% of solar UV light reaching the earth׳s surface, to induce human skin cancer is the subject of continuing controversy. This study was undertaken to investigate the role of reactive oxygen species in DNA damage produced by the exposure of human cells to UVA radiation. This knowledge is important for better understanding of UV-induced carcinogenesis. We measured DNA single-strand breaks and alkali-labile sites in human lymphocytes exposed ex vivo to various doses of 365-nm UV photons compared to X-rays and hydrogen peroxide using the comet assay. We demonstrated that the UVA-induced DNA damage increased in a linear dose-dependent manner. The rate of DNA single-strand breaks and alkali-labile sites after exposure to 1 J/cm² was similar to the rate induced by exposure to 1 Gy of X-rays or 25 μM hydrogen peroxide. The presence of either the hydroxyl radical scavenger dimethyl sulfoxide or the singlet oxygen quencher sodium azide resulted in a significant reduction in the UVA-induced DNA damage, suggesting a role for these reactive oxygen species in mediating UVA-induced DNA single-strand breaks and alkali-labile sites. We also showed that chromatin relaxation due to hypertonic conditions resulted in increased damage in both untreated and UVA-treated cells. The effect was the most significant in the presence of 0.5 M Na⁺, implying a role for histone H1. Our data suggest that the majority of DNA single-strand breaks and alkali-labile sites after exposure of human lymphocytes to UVA are produced by reactive oxygen species (the hydroxyl radical and singlet oxygen) and that the state of chromatin may substantially contribute to the outcome of such exposures.     

Optical radiation and the eyes with special emphasis on children

The Sun is the most abundant source of optical radiation for the child eye. New hand-held visible lasers are a threat to the child eye. Some scientific data suggest that near infrared radiation may cause cumulative damage in the ocular lens. The child eye usually is exposed to ambient solar radiation, gazing at the horizon. Ambient Sun ultraviolet radiation (UVR) exposure to the child is complex due to atmospheric scattering and strong dependence on background reflection. Solar exposure causes biological damage, only by photochemical mechanisms. UVR exposure to a child eye is mainly a threat to the anterior segment of the eye, but also age dependently to the retina. Above threshold exposure to UVR, for short delay onset of damage, causes a toxic reaction on the surface of the eye, snow blindness, and cataract. Sub-threshold daily exposure to UVR over decades is associated with several ocular surface pathologies and eye lid cancer. Visible radiation is a threat to the retina. A single above threshold exposure, for short delay onset of damage to the retina causes immediate photochemical Type II retinal damage, Sun blindness. A single exposure of the retina to a very high intensity laser beam may cause thermal or thermo-mechanical damage in the retina. In environments with high irradiance of optical radiation, the child eye should be protected. Legislation and public information is required for avoidance of damage from high intensity laser systems. More research is urgently needed to exclude the potential hazard of near infrared radiation.     

Radiation frost susceptibility and the association between sky exposure and leaf size

Plants growing in exposed and sheltered habitats have characteristic leaf structure and physiology that are traditionally associated with the total amount of incident sunlight. However, greater sky exposure also increases the susceptibility of leaves to radiation frost. Plants with large horizontal broadleaves are particularly susceptible to both overheating during the day and freezing at night. Moreover, the combined effects of high daytime sun-exposure and nighttime frost susceptibility could be particularly stressful to plant tissues. The purpose of this study was to evaluate the influence of elevation and microsite exposure (i.e. net loss of longwave radiation) on frost susceptibility, as well as the corresponding intraspecific variation in leaf size in the subalpine daisy (Erigeron peregrinus). Measured decreases in upper hemisphere infrared radiation (sky IR) of 0.014 W m^-2 m^-1 occurred with increasing elevation, beyond decreases predicted due to changes in air temperature and water content, resulting in an average decrease of 0.029 W m^-2 m^-1. Previous equations of sky IR based on air temperature and humidity were improved by adding this elevational term (r ² improved from 0.52 to 0.71). In contrast, a mean decrease of 6.5 W m^-2 m^-1 occurred with increasing sky exposure across a subalpine meadow. Leaf size in Taraxacum officinale decreased linearly with increasing elevation and a corresponding decline in sky IR. No difference in daily solar irradiance was measured across the same elevational gradient. Also, E. peregrinus had smaller leaves at high elevation microsites with greater sky exposure and decreased sky IR, while there was a much weaker association between leaf size and the amount of total daily solar irradiance. Differences in plant leaf structure and physiology traditionally associated with daytime sun-exposure may also be influenced by nighttime sky exposure and the susceptibility to radiation frosts.     

Oxidative inhibition of receptor-type protein-tyrosine phosphatase kappa by ultraviolet irradiation activates epidermal growth factor receptor in human keratinocytes

Ultraviolet (UV) irradiation rapidly increases tyrosine phosphorylation (i.e. activates) of epidermal growth factor receptors (EGFR) in human skin. EGFR-dependent signaling pathways drive increased expression of matrix metalloproteinases, whose actions fragment collagen and elastin fibers, the primary structural protein components in skin connective tissue. Connective tissue fragmentation, which results from chronic exposure to solar UV irradiation, is a major determinant of premature skin aging (photoaging). UV irradiation generates reactive oxygen species, which readily react with conserved cysteine residues in the active site of protein-tyrosine phosphatases (PTP). We report here that EGFR activation by UV irradiation results from oxidative inhibition of receptor type PTP-kappa (RPTP-kappa). RPTP-kappa directly counters intrinsic EGFR tyrosine kinase activity, thereby maintaining EGFR in an inactive state. Reversible, oxidative inactivation of RPTP-kappa activity by UV irradiation shifts the kinase-phosphatase balance in favor of EGFR activation. These data delineate a novel mechanism of EGFR regulation and identify RPTP-kappa as a key molecular target for antioxidant protection against skin aging.     

Effects of Ultraviolet-B Radiation Stress on the Abscisic Acid Status of Rumex patientia Leaves

To determine if increased abscisic acid (ABA) levels are associated with ultraviolet-B (UV-B) radiation (288–320 nm) stress, Rumex patientia L. plants were exposed to visible light with high or low (control) UV-B irradiance and then assayed for ABA by gas chromatography. Though leaf growth was inhibited by the UV-B irradiation, no differences in levels of free ABA were found between leaves from the two treatments after 1, 3 or 5 days of exposure. Unlike the situation in most environmental stresses, increased ABA levels are not associated with UV-B radiation stress. Further, photolysis or isomerization are not likely explanations for the absence of ABA increase. Calculations indicate that if ABA in the leaf were fully exposed to solar UV-B radiation only about 6.7% would be photolyzed by existing daily radiation at 40°N latitude, and 11.3% by radiation resulting from a 40% decrease in atmospheric ozone. The quantum yield for isomerization of cistrans-ABA by radiation in the 288–312 nm waveband was determined. Existing daily solar UV-B irradiation is capable of isomerizing ABA in solution to an equilibrium mixture of 50% cisjrans and 50%irans, trans-ABA., However, because of radiation attenuation in the leaf, it is estimated that only a small fraction of the cistrans-A.BA. would be isomerized.     

Differential responses of Nostoc sphaeroides and Arthrospira platensis to solar ultraviolet radiation exposure

During October to December 2003 we carried out experiments to assess the impact of high solar radiation levels (as normally occurring in a tropical region of Southern China) on the cyanobacteria Nostoc sphaeroides and Arthrospira (Spirulina) platensis. Two types of experiments were done: a) Short-term (i.e., 20 min) oxygen production of samples exposed to two radiation treatments (i.e., PAR+UVR—280–700 nm, and PAR only—400–700 nm, PAB and P treatments, respectively), and b) Long-term (i.e., 12 days) evaluation of photosynthetic quantum yield (Y) of samples exposed to three radiation treatments (i.e., PAB; PA (PAR+UV-A, 320–700 nm) and P treatments, respectively). N. sphaeroides was resistant to UVR, with no significant differences (P>0.05) in oxygen production within 20 min of exposure, but with a slight inhibition of Y within hours. A fast recovery of Y was observed after one day even in samples exposed to full solar radiation. A. platensis, on the other hand, was very sensitive to solar radiation (mainly to UV-B), as determined by oxygen production and Y measurements. A. platensis had a circadian rhythm of photosynthetic inhibition, and during the first six days of exposure to solar radiation, it varied between 80 and 100% at local noon, but cells recovered significantly during afternoon hours. There was a significant decrease in photosynthetic inhibition after the first week of exposure with values less than 50% at local noon in samples receiving full solar radiation. Samples exposed to PA and P treatments recovered much faster (within 2–3 days), and there were no significant differences in Y between the three radiation treatments when irradiance was low (late afternoon to early morning). Long-term acclimation seems to be important in A. platensis to cope with high UVR levels however, it is not attained through the synthesis of UV-absorbing compounds but it seems to be mostly related to adaptive morphological changes.     

Photoprotective Potential of Penta-O-Galloyl-β-DGlucose by Targeting NF-κB and MAPK Signaling in UVB Radiation-Induced Human Dermal Fibroblasts and Mouse Skin

Exposure of the skin to ultraviolet radiation can cause skin damage with various pathological changes including inflammation. In the present study, we identified the skin-protective activity of 1,2,3,4,6-penta-O-galloyl-β-D-glucose (pentagalloyl glucose, PGG) in ultraviolet B (UVB) radiation-induced human dermal fibroblasts and mouse skin. PGG exhibited antioxidant activity with regard to intracellular reactive oxygen species (ROS) generation as well as ROS and reactive nitrogen species (RNS) scavenging. Furthermore, PGG exhibited anti-inflammatory activity, inhibiting the activation of nuclear factor-kappaB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling, resulting in inhibition of the expression of pro-inflammatory mediators. Topical application of PGG followed by chronic exposure to UVB radiation in the dorsal skin of hairless mice resulted in a significant decrease in the progression of inflammatory skin damages, leading to inhibited activation of NF-κB signaling and expression of pro-inflammatory mediators. The present study demonstrated that PGG protected from skin damage induced by UVB radiation, and thus, may be a potential candidate for the prevention of environmental stimuli-induced inflammatory skin damage.     

Electromagnetic wave emitting products and “Kikoh” potentiate human leukocyte functions

Tourmaline (electric stone, a type of granite stone), common granite stone, ceramic disks, hot spring water and human palmar energy (called “Kikoh” in Japan and China), all which emit electromagnetic radiation in the far infrared region (wavelength 4–14 µm). These materials were thus examined for effects on human leukocyte activity and on lipid peroxidation of unsaturated fatty acids. It was revealed that these materials significantly increased intracellular calcium ion concentration, phagocytosis, and generation of reactive oxygen species in neutrophils, and the blastogenetic response of lymphocytes to mitogens. Chemotactic activity by neutrophils was also enhanced by exposure to tourmaline and the palm of “Kikohshi” i.e., a person who heals professionally by the laying on of hands. Despite the increase in reactive oxygen species generated by neutrophils, lipid peroxidation from unsaturated fatty acid was markedly inhibited by these four materials. The results suggest that materials emitting electromagnetic radiation in the far infrared range, which are widely used in Japan for cosmetic, therapeutic, and preservative purposes, appear capable of potentiating leukocyte functions without promoting oxidative injury.