Objective: To describe the effect of low ambient temperature on skin temperature and capillary refill (CR) time in forehead, sternum and finger pulp.
Methods: An observational, nonrandomized experimental study on 15 healthy subjects (6 females) in a cold room (8°C). Outcome measures were skin temperature and quantified CR test after application of a standardized blanching pressure (9 N/cm ) using digital photographic polarization spectroscopy to generate CR times.
To use Bioengineering methodology is used to achieve, at five anatomical sites, a detailed, quantitative assessment of the return of blood content to the blanched area, during the Capillary Refill (CR) test. An observational, non-randomized, experimental study on 23 healthy subjects (14 females) was performed in our climate controlled skin physiology laboratory. Our main outcome measures were based on the chronological assessment and quantification of red blood cell concentration (RBC) after the release of blanching pressure in the CR test, using Tissue Viability Imaging (TiVi), a digital photographic technique based on polarisation spectroscopy.
View Article and Find Full Text PDFBackground: Cosmetic products are known to be able to induce contact dermatitis. Contact dermatitis may also be induced by nickel, and it is estimated that up to 17% of women are allergic to nickel.
Objectives: The aim of the present study was to investigate whether nickel sensitized individuals react to make-up products containing pigments with nickel as an impurity.
Studying microvascular responses to iontophoresis of vasoconstricting drugs contributes to a better understanding of the regulatory mechanisms of cutaneous vessels, but measuring these responses with laser-Doppler flowmetry at basal blood flow conditions is technically challenging. This study aimed to investigate whether the measurement of cutaneous vasoconstrictor responses to noradrenaline (NA) and phenylephrine (PE), delivered by iontophoresis, is facilitated by predilatation of the microvascular bed using local heating. We used different drug delivery rates (100 s × 0.
View Article and Find Full Text PDFIn routine clinical phototesting and in basic research, naked eye dermatological assessment is the "gold standard" for determining the patient's minimal erythemal dose (MED). In UV-B testing with a divergent, radially attenuating beam of characterised dosimetry, laser Doppler perfusion imaging has been previously used to give quantitative description of reactivity to doses above the MED in addition to a "single-dose" objective determination of the MED itself. In the present paper, the recently developed tissue viability imaging (TiVi) technology is presented for the first time as a reliable, easily applicable, high-resolution alternative to LDPI in the divergent beam testing concept.
View Article and Find Full Text PDFBackground/aims: Skin is a viscoelastic material, comprised of fluidic and fibrous components. Changes in viscoelasticity can arise due to a number of conditions including dehydration, swelling (associated with injury or disease), impaired heart function, rehydration therapy, ageing, scarring, sun exposure and genetic conditions affecting connective tissue. Quantification of changes in skin viscoelasticity due to these processes is of great clinical interest in the fields of therapy monitoring, wound healing and disease screening.
View Article and Find Full Text PDFTissue Viability (TiVi) imaging is a promising new technology for the assessment of microcirculation in the upper human dermis. Although the technique is easily implemented and develops large amounts of observational data, its role in the clinical workplace awaits the development of standardised protocols required for routine clinical practice. The present study investigates the use of TiVi technology in a human, in vivo, localized, skin blood flow occlusion protocol.
View Article and Find Full Text PDFWhen one is studying the physiology of the cutaneous microcirculation there is a need for relevant non-invasive and versatile techniques. In this study we used a new optical device, the tissue viability imager (TiVi), to map changes in cutaneous microvascular concentrations of red blood cells during iontophoresis of vasoactive substances (noradrenaline (NA) and phenylephrine (Phe) for vasoconstriction and acetylcholine (ACh) and sodium nitroprusside (SNP) for vasodilatation). We aimed to present data both individually and pooled, using a four-variable logistic dose response model that is commonly used in similar in vitro vascular studies.
View Article and Find Full Text PDFSkin Res Technol
February 2009
Background: Operator-independent assessment of skin blanching is important in the development and evaluation of topically applied steroids. Spectroscopic instruments based on hand-held probes, however, include elements of operator dependence such as difference in applied pressure and probe misalignment, while laser Doppler-based methods are better suited for demonstration of skin vasodilatation than for vasoconstriction.
Objective: To demonstrate the potential of the emerging technology of Tissue Viability Imaging (TiVi) in the objective and operator-independent assessment of skin blanching.
Background: Tissue Viability Imaging (TiVi) is an emerging bioengineering technology intended for two-dimensional mapping of skin erythema and blanching. Before TiVi can be effectively used in studies of diseased or damaged skin, the variability in normal skin red blood cell concentration (RBC(conc)) requires evaluation.
Objective: To demonstrate how TiVi maps spatial and temporal variations in normal skin RBC(conc) at the dorsal side of the hand at rest and during post-occlusive hyperemia.
Background: Tissue Viability Imaging (TiVi) is a new bioengineering technology intended for remote two-dimensional mapping of skin red blood cell concentration (RBC(conc)). Before use in the laboratory, work-site and dermatology clinic, critical performance parameters of this emerging technology require careful evaluation.
Objective: To assess short- and long-term stability, image uniformity, distance and image size dependence, ambient light and curvature influence in a production batch of Tissue Viability Imagers.
Background/aims: Many clinical conditions that affect the microcirculation of the skin are still diagnosed and followed up by observational methods alone in spite of the fact that non-invasive, more user-independent and objective methods are available today. Limited portability, high cost, lack of robustness and non-specificity of findings are among the factors that have hampered the implementation of these methods in a clinical setting. The aim of this study is to present and evaluate a new, portable and easy-to-use imaging technology for investigation of the red blood cell (RBC) concentration in the skin microvasculature based on the method of polarization light spectroscopy using modified standard digital camera technology.
View Article and Find Full Text PDFCurrent knowledge about vascular function stems mainly from pharmacological in vitro studies using mounted vascular strips on a strain gauge. We know of no paper that has systematically examined the possibility of assessing the conventional dose-response effects of iontophoresis and laser Doppler investigation of vasoactive substances and compared those relations to data obtained from strips mounted on a strain gauge. We used the vasoactive substances acetylcholine (endothelium dependent) and sodium nitroprusside (endothelium independent) and an antagonist (atropine) to enable further investigations in the receptor physiology of iontophoresis.
View Article and Find Full Text PDFA method was developed to produce a composite image of microvascular networks with grayscales proportional to volumetric flows. Velocities in arterioles and venules were assessed with a high-resolution laser Doppler imager (LDI). The vascular structures were quantified from the micrograph with a computerized vessel detection algorithm.
View Article and Find Full Text PDFIontophoresis of vasoactive substances is a promising tool for studying pharmacological aspects of the (patho)physiology of the microvasculature. However, nonspecific microvascular responses are a common problem in most protocols used. We studied the effect of current density (mA/cm2), charge density (mC/cm2), drug concentration (mass %) and vehicle concentration (M) on the nonspecific vasodilatation during iontophoresis of sodium chloride, acetylcholine (ACh) and sodium nitroprusside (SNP).
View Article and Find Full Text PDFA method for the prediction of the average photon pathlength in turbid media has been developed. The method is based on spatially resolved diffuse reflectance with discrete source detector distances up to 2 mm. Light reflectance was simulated using a Monte Carlo technique with a one-layer model utilizing a wide range of optical properties, relevant to human skin.
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