The skin of fast-swimming sharks exhibits riblet structures aligned in the direction of flow that are known to reduce skin friction drag in the turbulent-flow regime. Structures have been fabricated for study and application that replicate and improve upon the natural shape of the shark-skin riblets, providing a maximum drag ...

The aim of our study was to investigate, whether masked hypertension (MH) and sustained hypertension (HT) are associated with alteration of resting skin blood flow and flowmotion. Subjects recruited to the study were assigned to three groups according to the results of blood pressure (BP) measurements. Resting blood flow (RF) ...

Decubitus ulcers (pressure ulcers) are localized areas of tissue breakdown in the skin and the underlying regions. Decubitus ulcers affect approximately 3 million people in the USA every year, including seniors, individuals with diabetes, and those who spend long periods in wheelchairs. Experimental studies demonstrate that static or dynamic normal ...

The aim of this study was to explore heat acclimation effects on cutaneous vascular responses and sweating to local ACh infusions and local heating. We also sought to examine whether heat acclimation altered maximal skin blood flow. ACh (1, 10, and 100 mM) was infused in 20 highly trained cyclists ...

This study examined the skin of two 1- to 2-year-old male giraffes and one adult male, determining skin thickness and histological structure with reference to it functioning as a component of the features required for the maintenance of blood pressure, dermal armor, or thermoregulation. It has been argued that a ...

Diffuse reflectance spectroscopy (DRS) uses the steady-state diffuse reflectance measured from the tissue surface to determine absorption and scattering properties of sampled tissue. Many inverse models used to determine absorber properties have assumed a homogeneous distribution of blood. However, blood in tissue is confined to blood vessels that occupy a ...

As people age, and especially for older people with diabetes, there is increased susceptibility to burns. However, this is not true for all older people or all people with diabetes. The factors that predict burn susceptibility in specific members of the population with diabetes have not been elucidated. To understand ...

Difficulty healing wounds and skin defects is a frequent problem in patients on chronic hemodialysis (HD) because of malnutrition, inflammation, and atherosclerosis (MIA) syndrome. The aim of the present study was to estimate the influence of peripheral blood flow changes during HD on the development of foot defects and its ...

Laser Doppler flowmetry (LDF) can be used for assessing the microcirculatory perfusion. However, conventional LDF (cLDF) gives only a relative perfusion estimate for an unknown measurement volume, with no information about the blood flow speed distribution. To overcome these limitations, a model-based analysis method for quantitative LDF (qLDF) is proposed. ...

Metal oxide nanoparticles are commonly used in personal-care formulations as protective agents against exposure to ultraviolet radiation. Although previous research has concluded that nanoparticles do not penetrate healthy skin, it remains contentious whether this conclusion holds under normal conditions of sunscreen use. Humans (n = 20) were exposed to sunscreens ...

Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, ...

Skin blood flow responses in the human forearm, assessed by three commonly used technologies-single-point laser-Doppler flowmetry, integrated laser-Doppler flowmetry, and laser-Doppler imaging-were compared in eight subjects during normothermic baseline, acute skin-surface cooling, and whole body heat stress (Δ internal temperature=1.0±0.2 degrees C; P<0.001). In addition, while normothermic and heat stressed, ...

Heat in blood pumps is generated by losses of the electrical motor and bearings. In the presented study the influence of tempered surfaces on bulk blood and adhesions on these surfaces was examined. Titanium alloy housing dummies were immersed in 25 mL heparinized human blood. The dummies were constantly tempered ...

To investigate how temperature influences changes in finger circulation induced by hand-transmitted vibration in healthy subjects, and the variability in individual response to both vibration and temperature. With two room temperatures (20 and 28°C), finger blood flow (FBF) and finger skin temperature (FST) were measured on the left middle fingers ...

OBJECTIVE: This study's objective was to determine the effect of therapeutic massage on peripheral blood flow utilizing dynamic infrared thermography in a constant temperature/humidity thermal chamber to assess noncontact skin temperature. DESIGN: The design was a repeated-measures crossover experimental design; the independent variable was treatment condition (massage, light touch, control). ...

Multispectral images of skin contain information on the spatial distribution of biological chromophores, such as blood and melanin. From this, parameters such as blood volume and blood oxygenation can be retrieved using reconstruction algorithms. Most such approaches use some form of pixelwise or volumetric reconstruction code. We explore the use ...

Skin functions and structure are significantly influenced by nutrients. Antioxidants protect the supportive layer of the skin against any damaging irradiation effects and the action of free radicals. A lack of suitable methods means that the pharmacokinetic properties of systemically applied carotenoids transferred into the skin remain poorly understood. In ...

We compared the inter-day reproducibility of post-occlusive reactive hyperemia (PORH) assessed by single-point laser Doppler flowmetry (LDF) and laser speckle contrast analysis (LSCI), and the reproducibility of local thermal hyperemia (LTH) assessed by LDF, laser Doppler imaging (LDI) and LSCI. We also tested whether skin blood flow assessment by LDF ...

The aim of the study was to investigate the skin microcirculation blood flow and flowmotion response to heat stress in normotensive subjects with familial predisposition to hypertension and in hypertensive patients. Normotensives without [NT(-)] or with [NT(+)] familial predisposition and subjects with newly diagnosed hypertension (HT) were studied. Clinic blood ...

BACKGROUND: To evaluate the correlation between ankle:brachial indices (ABI) and visible light reflectance spectroscopy hyperspectral imaging (HSI) determinations of oxygenated and deoxygenated hemoglobin (oxyHgb and deoxyHgb) levels in the skin of the distal lower extremity. This is a prospective, open, comparator trial which took place at the Vascular laboratory of ...

Both structural and functional evaluations of the endothelium exist in order to diagnose cardiovascular disease (CVD) in its asymptomatic stages. Vascular reactivity, a functional evaluation of the endothelium in response to factors such as occlusion, cold, and stress, in addition to plasma markers, is the most widely accepted test and ...

Human skin blood flow is controlled via dual innervation from the sympathetic nervous system. Reflex cutaneous vasoconstriction and vasodilation are both impaired with primary aging, rendering the aged more vulnerable to hypothermia and cardiovascular complications from heat-related illness. Age-related alterations in the thermoregulatory control of skin blood flow occur at ...

Ear (aural) hematomas occur when blood vessels in the pinna rupture secondary to trauma or excessive head shaking. Blood fills the space between the skin and the cartilage, causing pain and potential deformity of the ear. In this column, I discuss surgical treatment of aural hematomas in the dog.

Non-suicidal self-injury (NSSI) is a growing clinical problem, especially among adolescents and young adults. Anecdotal accounts, clinical reports, and popular media sources suggest that observing the blood resulting from NSSI often plays an important role in the behavior's reinforcement. However, research to date has not systematically assessed the role of ...

The purposes of this study were to quantify the nonlinear properties of sacral skin blood flow oscillations (BFO) and to explore their relationships with impaired vasodilatory function in people at risk for pressure ulcers. A total of 25 people with various levels of vasodilatory functions were studied, 10 people with ...

The perfusion of forearm skin with blood was studied by the method of laser Doppler flowmetry (LDF) in 94 healthy volunteers. We studied the reaction of the microvascular bed to the transient ischemia, which was initiated by the forearm occlusion. After occlusion, we registered, on average, a 4-fold increase of ...

Cutaneous vasodilation associated with whole-body heat stress occurs via withdrawal of adrenergic vasoconstriction and engagement of cholinergic "active" vasodilation, the latter of which attenuates cutaneous vasoconstrictor responsiveness. However, the precise neurotransmitter(s) responsible for this sympatholytic-like effect remain unknown. In skeletal muscle, ATP inhibits adrenergically mediated vasoconstriction. ATP also may be ...

Assessment of blood circulation in pressure ulcers can be beneficial for predicting the severity of tissue damage and making the prognosis. Here, we evaluated the usefulness of laser speckle flowgraphy (LSFG) for assessing skin blood flow in pressure-induced ischemic wounds in rats in comparison with skin temperature measurements by thermography, ...

Cold intolerance is an inability to tolerate cold temperatures and is accompanied by symptoms including headache, shoulder discomfort, dizziness and palpitations. The current study was performed to examine whether reflexology therapy affected cold intolerance in human subjects and whether the treatment was systemically effective. Ten female volunteer examinees with subjective ...

The structure and function of blood vessels varies along the vascular tree. Endothelial dysfunction is a hallmark of increased cardiovascular (CV) risk that can be assessed by several methods, some of which are invasive and of restricted application. The aim of this study was to determine whether the laser Doppler ...

Hypoxia decreases core body temperature in animals and humans during cold exposure. In addition, hypoxia increases skin blood flow in thermoneutral conditions, but the impact of hypoxic vasodilation on vasoconstriction during cold exposure is unknown. In this study, skin blood flow was assessed using laser-Doppler flowmetry, and cutaneous vascular conductance ...

The cold hand sign (CHS) is a distinct feature of multiple system atrophy (MSA), but its pathophysiology is poorly understood. We, therefore, conducted a study to examine the skin temperature and the skin blood flow at rest and after local heating in 6 age-matched MSA patients with CHS (MSA + ...

Different topical local anaesthetics have varying effects on skin blood flow and vascular reactivity. We compared the vasoactive properties of Rapydan, a new topical local anaesthetic, with those of Ametop and EMLA creams in 20 healthy volunteers. Blood flow and vascular reactivity in the forearm skin were assessed by laser ...

BACKGROUND: Facial skin exhibits unique biophysical properties that are distinct from skin belonging to other areas of the body. Small to large regional differences in biophysical properties between facial sites are observed. Technological advances in dermatological research allow a quantitative study of the biophysical qualities of the face and its ...

Hydrotherapy and whirlpool are used to increase skin blood flow and warm tissue. However, recent evidence seems to show that part of the increase in skin blood flow is not due to the warmth itself but due to the moisture content of the heat. Therefore, two series of experiments were ...

PURPOSE: To examine the relationship between optic nerve head (ONH) and finger blood flow in subjects with and without a primary vascular dysregulation (PVD). METHODS: ONH blood flow and finger blood flow was measured in 15 subjects with PVD and in 24 subjects without PVD. PVD was defined as being ...

The enhancement of blood fluidity may lead to improvements in skin problems resulting from unsmooth circulation or blood stagnation. Since a 50% ethanolic extract (CH-ext) obtained from unripe Citrus hassaku fruits may be a useful ingredient in skin-whitening cosmetics, the present study was designed to examine the effect of CH-ext ...

The aim of this preliminary study was to review the actual state of knowledge concerning the mechanisms underlying compression medical stockings action on the skin blood flow (SBF) in capillaries. SBF was assessed by measuring the thermal conductivity of living-tissues using μHematron ambulatory device. The investigation was performed for different ...

Regular physical activity leads to increased endothelium-dependent vasodilatation. Postocclusive reactive hyperemia (PRH) is a transient increase of blood flow after the release of an arterial occlusion and has been used as a clinical tool to estimate endothelial function. The aim of our study was to assess the potential effect of ...

Vector-borne diseases are still a major mortality factor in Africa and South-east Asia and effective mosquito repellents are therefore needed. An efficient and safe in-vitro assay system using artificial blood and skin substitute could facilitate the development of novel repellents, as most assays currently rely on human subjects or vertebrate ...

To study optic nerve lesions, changes in blood flow to the optic nerve, and permeability of micro blood vessels and histopathology in diabetic rats. Male Wistar rats (n=20) were randomly divided into control and diabetic groups. The diabetic model was prepared by a single injection of streptozotocin (50mg/kg) into the ...

Laser Doppler imaging (LDI) is a relatively new method for assessing the functional aspect of superficial skin blood flow in systemic sclerosis (SSc) and Raynaud's phenomenon. The present study investigated the dynamic behavior of digital skin microvascular blood flow before and after cold stimulus (CS) in SSc patients and in ...

Our previous studies found that segmental effect of spinal nerve plays an important role in acupuncture stimulation (AS) on nail-fold microcirculation. Calcitonin-gene related peptide (CGRP) is a potent endogenous vasodilator. Therefore, the aim of the present study was to investigate the effect of AS on skin blood flow (SBF) and ...

The past 10-15 years has been a time of focus on the mechanisms of control in the human cutaneous circulation. Methodological developments have provided powerful means for resolving the important contributors to the reflex control of skin blood flow (thermoregulatory control) and also for the equally impressive effects of direct ...

Dietary antioxidants exert a photoprotective effect against UV radiation. However, the mechanism underlying the beneficial effects on skin of orally administered antioxidant is not very clear. The present study aimed to investigate the UVB-induced total antioxidant capacity (TAC) perturbation both in skin and blood and to study the beneficial mechanism ...

A 43-year-old African-American female with anemia secondary to uterine leiomyomas and menorrhagia presented with induration and stiffness of the right arm and hand four weeks after receiving intravenous iron infusions at multiple infusion sites along the right proximal forearm. Multiple intravenous sites between her right antecubital fossa and wrist had ...

Acute mental stress induces sympathetic activation and influences vasomotor control in various organs. In the present study, to better understand the effect of physical training on peripheral vasomotor control during acute mental stress, we compared the skin vascular responses to mental arithmetic (MA) in physically trained and untrained humans. Eight ...

Flow around two circular cylinders in a side-by-side arrangement normal to the free stream with heat release from one of the cylinders is studied experimentally. This flow, with no heat release, is known to exhibit a range of flow regimes at different cylinder spacings. In particular, the wake exhibits well-known ...

BACKGROUND: To protect against ischemia, pressure-induced vasodilation (PIV) causes an increase in skin blood flow. Endothelial dysfunction, which is commonly found in older patients and those with diabetes, and global temperatures can affect the resting blood flow in skin, which may reduce the blood flow during and after the application ...

Experiments on rats showed that complete Freund's adjuvant-induced low-grade fever and pyrogenal-induced fever are accompanied by an increase in the content of Mn, Cu, Zn, and Se in the thoracic duct lymph. Our results indicate that the lymphatic system supplies trace elements to the circulation, which compensates for a deficiency ...