In this study the dielectric properties are reported for human skin tissues over the frequency range 1-450 MHz at 36 degrees C. Healthy volunteers, collagen disease patients and dialysis patients are studied in order to investigate, primarily, the variability among (1) different regions of one individual, (2) the same region ...

AIM: Photodynamic therapy (PDT) involves the use of photosensitizing drugs combined with light to treat tumors. Laser systems, the current source of light for PDT, have several inherent drawbacks: the spectrum is essentially monochromatic which may be problematic for second generation photosensitizers, the systems are bulky and nearly impossible to ...

Laser and flash-lamp technology now offers the potential for rapid, safe, and effective treatment of unwanted hair. An ever-increasing number of published studies have confirmed the long-term efficacy of laser and flash-lamp treatment. The benefits of this technology have largely been limited to individuals with dark hair and relatively fair ...

BACKGROUND AND OBJECTIVE: New, non-ablative methods can be used in skin rejuvenation. Histologic analysis of non-ablative IPL effects on facial, sun-damaged skin. STUDY DESIGN/MATERIALS AND METHODS: Five female subjects, wrinkle class I or II and Fitzpatrick skin types I, II, and III. IPL treatment: once monthly, 560-nm cut-off filters, spot ...

Functional reach (FR) significantly increases with additional sensory information from the fifth metacarpal surface of the dominant hand. The purpose of this study was to determine the relationship between the innervation density of the skin above the fifth metacarpal surface of the palm and the increase of FR with an ...

Species of Collinsia and Tonella, the two sister genera of self-compatible annuals that constitute tribe Collinsieae, show extensive variation in floral size and morphology and in patterns of stamen and style elongation during the life of the flower (anthesis). We used a nuclear ribosomal ITS phylogeny, independent contrasts, and phylogenetically ...

BACKGROUND AND OBJECTIVES: Previous studies with PhotoDynamic Therapy (PDT) in bladder and bronchi have shown that due to scattering and reflection, the actually delivered fluence rate on the surface in a hollow organ can be significantly higher than expected. In this pilot study, we investigated the differences between the primary ...

BACKGROUND AND OBJECTIVES: Helicobacter pylori (HP) is an endemic pathogenic bacterium causing gastritis and gastroduodenal ulceration in humans and is linked to the development of gastric malignancies. These first human in vivo studies investigated the photoeradication of HP using laser and white light. STUDY DESIGN/MATERIALS AND METHODS: In 13 HP-positive ...

OBJECTIVES: Vibrotactile thresholds on the fingers were compared using two alternative methods of controlling contact with a vibrating probe: control of the force of contact with the probe (force control) and control of skin indentation produced by the probe (indentation control). Both systems had the same control of push force ...

BACKGROUND AND OBJECTIVES: Oral bacteria can be killed by light in the presence of a suitable photosensitizer, and this could be used in the treatment of oral infections. In these diseases, however, bacteria are present as biofilms, which are refractive to antimicrobial agents. The purpose of this study was to ...

Noninvasive and real-time analysis of skin properties is useful in a wide variety of applications. In particular, the quantitative assessment of skin in terms of hemoglobin and melanin content, as well as in terms of its light scattering properties, is a challenging problem in dermatology. We present here a technique ...

Different types of melanin pigments have recently been identified and recognized as critical determinants of the photosensitivity of individuals. Eumelanin, the black to brown melanin pigments, are believed to protect against ultraviolet-induced cell damage, while phaeomelanin, the reddish brown variant, is thought to be photosensitizing. The relative, qualitative and absolute ...

Skin cells produce endogenous opioids in response to light. This results in increased skin and plasma levels of endogenous opioids. Increased plasma levels of endogenous opioids may improve mood and affect behavior. The author suggests that improvement in mood after exposure to light may be related to the light-induced increase ...

One of the most important physical processes occurring in Rb frequency standards is the light shift, which depends strongly on the intensity and the optical frequency detuning of the pumping light. This paper presents a method to compensate the light shift by means of two-laser pumping. The two-laser pumping schemes ...

The aim of this study was to differentiate the response pattern characteristics of sympathetic skin responses (SSR) between unmedicated first psychotic subjects and healthy controls. We recorded SSR to novel auditory stimuli in 13 psychotic subjects and in 19 controls. There was no constant delay between a sudden change in ...

Melanosomes in keratinocytes of Black skin are larger and distributed individually whereas those within keratinocytes of Caucasian skin are smaller and distributed in clusters. This disparity contributes to differences in skin pigmentation and photoprotection, but the control of these innate distribution patterns is poorly understood. To investigate this process, cocultures ...

OBJECTIVE: The high melanin concentration in dark skin prevents the observation of a blanch response to light finger pressure. The objective of this study was to determine the ability of visible and near-infrared spectroscopy (the technique used in pulse oximetry) to monitor a blanch response from in vivo spectra in ...

In situ light dosimetry during photodynamic therapy (PDT) of malignant pleural mesothelioma (MPM) after tumour resection facilitates the delivery of a controlled light distribution to the inner thoracic surface. Illumination of the diaphragm-induced sinus, however, remains difficult. Our aim was to develop a wedge-shaped light applicator with incorporated light dosimetry ...

BACKGROUND: Aminolevulinic acid hydrochloride (ALA, Levulan) applied topically to actinic keratoses (AKs) leads to accumulation of the photosensitizer protoporphyrin IX, which, when activated by exposure to light, eradicates AKs. OBJECTIVE: We examined the safety and efficacy of photodynamic therapy using topical 20% ALA in a solution formulation and varying blue ...

Light damage research began during the early years of laser light exploration. There is a clear and significant literature that identifies an easily demonstrated retina-pigment epithelium pathology which is associated with short wavelength exposures below 520 nm. Recent interest has expanded because of the growing evidence for a blue light ...

Photoinactivation was employed to eliminate EHDV-2 from in vitro produced bovine embryos experimentally exposed to this virus. Immature oocytes were matured, fertilized, and cultured in chemically defined conditions. All treatments were performed on zygotes. Developmental potential of zygotes and cell numbers of resulting hatched blastocysts were assessed after exposure to ...

BACKGROUND: Ultraviolet radiation (UVR) has a variety of effects on human skin. Best known are the effects of UVB (290-320 nm) and UVA2 (320-340 nm), which cause DNA damage and increased risk of cancer. However, the effects of UVA1 (340-400 nm) have been not completely investigated. METHODS: The effects of ...

BACKGROUND: Photodynamic therapy (PDT) is useful for treatment of epidermal neoplasia but may also have a role in the treatment of inflammatory dermatoses. OBJECTIVES: To study the effect of PDT in patients with acne. METHODS: Three men and 10 women who suffered from intractable acne vulgaris were treated using PDT ...

The reactive nature of species derived from oxygen, such as singlet oxygen and hydrogen peroxide, has been exploited in the clinical setting for targeting bacteria, viruses, and tumor cells by photodynamic excitation of a variety of chromophores. This modality, termed photodynamic therapy (PDT), is currently being used to treat some ...

OBJECTIVE: The purpose of this study was to assess and to formulate physically an irreducible set of irradiation parameters that could be relevant in the achieving reproducible light-induced effects in biological systems, both in vitro and in vivo. BACKGROUND DATA: Light-tissue interaction studies focusing on the evaluation of irradiation thresholds ...

BACKGROUND AND OBJECTIVE: The goal of this study was to evaluate various creams for their capability to protect photosensitized skin from visible light. STUDY DESIGN/MATERIALS AND METHODS: Two cover creams and creams containing various combinations of Vaseline with TiO(2), ZnO, and Fe(2)O(3) were used to measure the reduced light transmission ...

BACKGROUND AND OBJECTIVE: A human glioma spheroid model is used to investigate the efficacy of different light delivery schemes in 5-aminolevulinic acid (ALA)--mediated photodynamic therapy (PDT). The results provide the rationale for the development of an indwelling balloon applicator for optimizing light delivery. STUDY DESIGN/MATERIALS AND METHODS: Human glioma spheroids ...

BACKGROUND AND OBJECTIVE: Application of laser irradiation targeting the inner ear has to be investigated for therapeutic effectiveness in cochlear injury and dysfunction. In vitro data demonstrate low-level laser-induced photochemical and photobiologic cell response, depending on cell type and irradiation parameters such as light dose. The aim of the presented ...

Light fractionation with dark periods of the order of hours has been shown to considerably increase the efficacy of 5-aminolevulinic acid-photodynamic therapy (ALA-PDT). Recent investigations have suggested that this increase may be due to the resynthesis of protoporphyrin IX (PpIX) during the dark period following the first illumination that is ...

Wrinkle formation caused by photoaging clearly involves changes of extracellular matrix components and mechanical properties of the skin. Recently, it was reported that the topical application of 1alpha, 25-dihydroxyvitamin D(3) to hairless mouse skin induced wrinkling. Here we have evaluated the effect of topical application of 1alpha, 25-dihydroxyvitamin D(3), which ...

OBJECTIVE: To evaluate the safety of sodium bisulfate for use in horse barn environments by determining its irritant effect on skin and hooves. ANIMALS: 6 female mixed-breed ponies. PROCEDURE: Sodium bisulfate was applied to clipped intact skin of 6 ponies to evaluate its irritant effect after single (48 hours) and ...

Using spatially resolved, steady state diffuse reflectometry, a directional dependence was found in the propagation of visible and near infrared light through human skin in vivo. The skin's reduced scattering coefficient mu(s)' varies by up to a factor of two between different directions of propagation at the same position. This ...

Application of non-ionising radiation with or without photosensitizers is rather common in dermatology. Though the method itself was described in ancient times, its routine use in medicine based on scientific research started in the second half of the 20th century. Light can be used in three different patterns: phototherapy (UV-A ...

OBJECTIVES: To assess (i) the optical properties and depth of penetration of varying wavelengths of light in ex-vivo human bladder tissue, using specimens of normal bladder wall, transitional cell carcinoma (TCC) and bladder tissue after exposure to ionizing radiation; and (ii) to estimate the depth of bladder wall containing cancer ...

Neurosensory tactile functions were investigated in human subjects by two different and complementary experimental approaches. First, a conventional psychophysical method (two-point gap discrimination) was used to determine the tactile discrimination threshold by analyzing the subjects' ability to detect a gap of variable width between two contact points when a series ...

BACKGROUND: Photodamaged skin is characterized not only by rhytides, but also by epidermal and dermal atrophy, rough skin texture, irregular pigmentation, telangiectasias, laxity, and enlarged pores. There is growing interest in the development of noninvasive methods to treat photodamaged skin. Skin photorejuvenation is the visible improvement of photodamaged skin using ...

Based on the opinion that 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) may be disadvantageous to Oriental patients with dark skin, including Japanese, because the competing chromophore melanin inhibits the photochemical reaction, we assessed the therapeutic effects when Japanese AK were treated with ALA-PDT. Fifty-three lesions in ten patients were followed up ...

Photodynamic therapy (PDT) has been studied and applied to various disease processes. The potential of PDT for selective destruction of target tissues is especially appealing in cardiovascular disease, in which other existing interventional tools are somewhat nonselective and carry substantial risk of damage to the normal arterial wall. Enthusiasm for ...

The ability of a spatial population of cutaneous, Adelta, and C mechano-nociceptors to encode the location and intensity of a noxious, cutaneous indentation was examined using an isolated preparation in a rat model. Skin and its intact innervation were harvested from the medial thigh of the rat hindlimb and placed ...

We have used two modern computerized handheld reflectometers, the Photovolt ColorWalk colorimeter (a tristimulus colorimeter; Photovolt, UMM Electronics, Indianapolis, IN) and the DermaSpectrometer (a specialized narrow-band reflectometer; Cortex Technology, Hadsund, Denmark), to compare two methods for the objective determination of skin and hair color. These instruments both determine color by ...

The self-tanning agent dihydroxyacetone (DHA) was applied to human skin samples, and its effect on light absorption was followed in time to study the DHA influence inside the different layers of skin. Application of DHA shows increased light absorption in the visible light region, as evidenced by skin tanning. The ...

Recent investigations have reported contradictory results on the influence of low-power laser light on wound healing. Low-power laser with a power output of 250 mW and an emitted laser light of 670 nm have been insufficiently investigated to date. The effect of a 250-mW/670-nm laser light on the healing of ...

OBJECTIVE: To test the effectiveness of 5-aminolevulinic acid (ALA)-induced photodynamic endometrial ablation in the rhesus monkey under varying conditions of light delivery (fractionated versus continuous) and steroid priming. METHODS: Photodynamic endometrial ablation was carried out in 17 rhesus monkeys that were either postmenopausal or in the early proliferative phase. Four ...

The effectiveness of different types of auditory prepulses in eliciting skin conductance orienting and in producing prepulse inhibition (PPI) of the acoustic startle eyeblink was studied in two experiments. A discrete white noise prepulse produced greater PPI than either a continuous white noise, a discrete tone, or a continuous tone. ...

A laser-based method of increasing the enantiomeric excess of a chiral enantiomer in a racemic mixture is described. Neither the initial reagents nor the incident light need be chiral. Both formal and computational results show that enhancement of the enantiomer of choice, controlled by laser parameters, can be extensive.

Phenomena occurring at the interface between skin and a glass pad, alternatively moved at its surface, are described by direct observation and measured by recording the force on the pad induced by the skin displacement. Static and dynamic friction coefficients are determined as a function of the load applied on ...

OBJECTIVES: To assess the effectiveness of low level laser therapy in the treatment of venous leg ulcers. SEARCH STRATEGY: Searches of 19 databases, hand searching of journals and conference proceedings from 1948 onwards, and examination of bibliographies. SELECTION CRITERIA: Randomised controlled trials comparing low level laser therapy with: sham laser; ...

Conventional treatment options for hypertrichosis and hirsutism are tedious and time consuming. Laser hair removal offers an efficient way to permanently reduce excessive hair growth. Hair is damaged using the principle of selective photothermolysis with wavelengths of light well absorbed by follicular melanin and pulse durations that selectively thermally damage ...

A new set-up of a small Cs clock has been successfully experimentally tested. The short-term stability (2x10(-12)) and the long-term stability (3.5x10(-13) for a day sample time) have been measured. Only one laser is needed without any frequency shift device. The light frequency shift caused by diffuse light was calculated ...

To test theoretical assumptions supporting the use of near-infrared spectroscopy (NIRS) in clinical practice, we examined the behaviour of NIR light transmission and attenuation in the human head. Sterile probes for emitting and detecting NIR light at a fixed separation of 40 mm were placed in turn on intact skin, ...