Normal Skin Temperature Research Articles

Skin thermal recovery following cryotherapy: acomparison of liquid nitrogen and liquid nitrous oxide.

Cryotherapy is a common technique used in the management of superficial skin lesions, with current advice on the correct timing for freeze-thaw cycles based on nonscientific visual skin appearances. We investigated the effect of cryotherapy on thermal thawing times by creating a porcine skin model in a laboratory setting maintained at normal skin temperature and comparing liquid nitrogen and liquid nitrous oxide. Thermal assessment was performed using a thermal camera attached to an iPhone 11Pro® smartphone. Liquid nitrogen reduced skin temperature to -60 °C after 5 s of application, recovering to 0 °C after 70 s. Liquid nitrous oxide reduced skin temperature to -34.8°C after 5 s but had a faster recovery to 0 °C after only 20 s. Both cryogens required a thawing period of 5 min to recover to normal skin temperature. We therefore suggest that optimum cellular degradation should allow for 5-min freeze-thaw cryotherapy cycles; a slower thawing period than is in current common practice.

A V-Y shaped flap with digital artery nerve at metacarpophalangeal joint was used to repair the defect of middle and distal phalanx

To explore a surgical method for the reconstruction of volar soft tissue defect and sensory and vascular repair in middle and far phalangeal digits. From January 2016 to January 2020, a total of 14 patients , 9 males and 5 females, ages ranging from 22 to 69 years old, and with volar soft tissue defects in the middle and distal digits 2 to 4, underwent surgical reconstruction using the V-Y shaped flap with digital artery and nerve at the metacarpophalangeal joint. The defect area was (2.0~2.5) cm×(1.5 ~2.0) cm. The procedure involved the harvest of a V-Y shaped flap with the digital artery and nerve from the metacarpophalangeal joint. Flap design, dissection of blood vessels and nerves, and anastomosis with the digital artery and nerve were performed according to a standardized protocol., Functional exercise of affected finger was initiated 3 weeks postoperatively. Subsequent assessments were conducted to evaluate finger pulp sensation, shape and other relevant parameters. According to the upper extremity functional evaluation standard set up by Hand Surgery Branch of Chinese Medical Association, the surgical outcomes were evaluated. All 14 cases demonstrated successful tissue transplantation, , with immediate recovery of sensation observed in 10 cases with distal finger pulp defects. Four patients with middle phalangeal defects experienced gradual sensory recovery within 2 to 3 months postoperatively. Thirteen patients were followed up for a mean duration of (8.8 ± 4.49) months, during which satisfactory outcomes were observed. The average two-point resolution of the finger pulp was 4-6mm, and sensory function evaluation yielded a score of S3 or above. Patients exhibited realistic finger shape, normal skin color and temperature, good wear resistance, and cold resistance. Furthermore, finger joint function was essentially normal. The V-Y shaped flap with digital artery and nerve at the metacarpophalangeal joint offers a suitable solution for repairing the defect of the middle or distal phalangeal finger. This technique is characterized by its simplicity, low risk, and favorable outcomes, including restored finger shape, blood supply and sensation. Moreover, high patient satisfaction was achieved.

In Vitro-In Vivo Correlation of Buprenorphine Transdermal Systems Under Normal and Elevated Skin Temperature.

Application of external heat using a heating pad over buprenorphine transdermal system, Butrans® has been shown to increase systemic levels of buprenorphine in human volunteers. The purpose of this study was to perform in vitro permeation studies at normal as well as elevated temperature conditions to evaluate the correlation of in vitro data with the existing in vivo data. In vitro permeation tests (IVPT) were performed on human skin from four donors. The IVPT study design was harmonized to a previously published clinical study design and skin temperature was maintained at either 32 ± 1°C or 42 ± 1°C to mimic normal and elevated skin temperature conditions, respectively. IVPT studies on human skin were able to demonstrate heat induced enhancement in flux and cumulative amount of drug permeated from Butrans® which was reasonably consistent with the corresponding enhancement observed in vivo. Level A in vitro-in vivo correlation (IVIVC) was established using unit impulse response (UIR) based deconvolution method for both baseline and heat arms of the study. The percent prediction error (%PE) calculated for AUC and Cmax values was less than 20%. The studies indicated that IVPT studies performed under the same conditions as those of interest in vivo may be useful for comparative evaluation of the effect of external heat on transdermal delivery system (TDS). Further research may be warranted to evaluate factors, beyond cutaneous bioavailability (BA) assessed using an IVPT study, that can influence plasma exposure in vivo for a given drug product.

Early Skin Temperature Characteristics of the Kennedy Lesion (Kennedy Terminal Ulcer)

BACKGROUND: Pressure injuries are associated with skin temperature changes, but little is known about skin temperature characteristics of the Kennedy Lesion (KL). PURPOSE: The purpose of this study was to describe early skin temperature changes in KLs using long-wave infrared thermography. METHODS: KLs were identified from chart review in 10 ICU patients. Skin assessments were performed within 24 hours of new skin discoloration. Temperature measurements were performed using a long-wave infrared thermography imaging system. Relative Temperature Differential (RTD) between the discolored area and a selected control point was calculated. RTDs of > +1.2 °C and < -1.2 °C were considered abnormal. Demographic data and observable characteristics of the KL were collected when available. Descriptive statistics (Mean +/- SD; %) were used. RESULTS: The major finding of this study was that there were no early skin temperature differences between the KLs and surrounding skin. CONCLUSION: The early stage of the KL may be limited to microvascular injury which results in a normal skin temperature. More studies are needed to verify this finding and to ascertain whether KL skin temperature changes over time. The study also supports the bedside use of thermography in skin temperature assessment.

Vitamin D Deficiency and its Relation to Lipid Profile

Background Vitamin D deficiency is considered as a major public health problem all over the world. Vitamin D acts as a hormone with multi-functions. The main source of vitamin D is solar UV radiation, which converts 7-dehydrocholesterol to pro-vitamin D which is modified to vitamin D given normal skin temperature. Vitamin D deficiency is a common disorder presents in all ages and in both genders. Vitamin D plays an important role in modulating the immune response to infections and reduction inflammatory response. Vitamin D deficiency has a genetic predisposition. There is a correlation between low 25-hydroxyvitamin D levels and dyslipidemia, so correction of vitamin D deficiency is important for treating disturbance in lipid profile. Repletion of 25-hydroxy vitamin D levels raised serum calcium level and decrease parathyroid hormone levels.

Reproducibility and robustness of motor cortical stimulation to assess muscle relaxation kinetics

Transcranial magnetic stimulation (TMS) of the motor cortex can be used during a voluntary contraction to inhibit corticospinal drive to the muscle and consequently induce involuntary muscle relaxation. Our aim was to evaluate the reproducibility and the effect of varying experimental conditions (robustness) of TMS‐induced muscle relaxation. Relaxation of deep finger flexors was assessed in 10 healthy subjects (5 M, 5 F) using handgrip dynamometry with normalized peak relaxation rate as main outcome measure, that is, peak relaxation rate divided by (voluntary plus TMS‐evoked)force prior to relaxation. Both interday and interrater reliability of relaxation rate were high with intraclass correlation coefficient of 0.88 and 0.92 and coefficient of variation of 3.8 and 3.7%, respectively. Target forces of 37.5% of maximal voluntary force or higher resulted in similar relaxation rate. From 50% of maximal stimulator output and higher relaxation rate remained the same. Only the most lateral position (>2 cm from the vertex) rendered lower relaxation rate (mean ± SD: 11.1 ± 3.0 s−1, 95% CI: 9.0–13.3 s−1) compared to stimulation at the vertex (12.8 ± 1.89 s−1, 95% CI: 11.6–14.1 s−1). Within the range of baseline skin temperatures, an average change of 0.5 ± 0.2 s−1 in normalized peak relaxation rate was measured per 1°C change in skin temperature. In conclusion, interday and interrater reproducibility and reliability of TMS‐induced muscle relaxation of the finger flexors were high. Furthermore, this technique is robust with limited effect of target force, stimulation intensity, and coil position. Muscle relaxation is strongly affected by skin temperature; however, this effect is marginal within the normal skin temperature range. We deem this technique well suited for clinical and scientific assessment of muscle relaxation.

Higher Periwound Temperature Associated with Wound Healing of Pressure Ulcers Detected by Infrared Thermography.

Visual and empirical assessments do not enable the early detection of wound deterioration or necroses. No suitable objective indicator for predicting poor wound-healing is currently available. We used infrared thermography to determine the association between wound temperature and pressure-wound healing. We examined patients with grades 2–4 pressure ulcers from a medical center in southern Taiwan and recorded the temperatures of the wound bed, periwound, and normal skin using infrared thermographic cameras. A total of 50 pressure ulcers and 248 infrared-thermography temperature records were analyzed. Normal skin temperature was not related to pressure ulcer wound healing. In a multivariate analysis, higher malnutrition universal-screening-tool scores were associated with poor wound-healing (p = 0.020), and higher periwound-temperature values were associated with better wound-healing (p = 0.028). In patients who had higher periwound-skin temperature than that of the wound bed, that result was also associated with better wound-healing (p = 0.002). Wound-bed and periwound temperatures differed significantly with the grade of the pressure ulcer, and a high periwound temperature was positively correlated with wound healing. Infrared thermography can objectively serve as indicators for assessing pressure-ulcer healing.

Kick Ring LL: A Multi-Sensor Ring Capturing Respiration, Electrocardiogram, Oxygen Saturation, and Skin Temperature1.

With the growing trend towards personalized health, wearable fitness trackers have become a staple of the consumer electronics industry. As the prevalence of such devices booms, the medical community has been compelled to investigate the potential of such devices and explore how they can be used to create positive clinical outcomes. In this report we detail a smart-ring capable of determining heart rate (HR), respiratory rate (RR), blood oxygen saturation (SpO2), and temperature. The ring implements a photoplethysmogram (PPG), electrocardiogram (ECG), and thermistor to attain these metrics. After evaluation, significant correlation was found between the experimentally reported HR and RR recordings with their respective standards (p<0.05). Experimentally derived SpO2 had trial-dependent similarities with its reference standards, and temperature measurements were within expected values of normal skin temperature.

Effect of Controlled Heat Application on Topical Diclofenac Formulations Evaluated by In Vitro Permeation Tests (IVPT) Using Porcine and Human Skin.

Heat therapy is widely used for pain relief and may unintentionally be used in conjunction with pain relieving topical formulations. The purpose of this study was to evaluate the influence of heat on the permeation of diclofenac through porcine and human skin, comparing four marketed products. In vitro permeation tests (IVPT) were performed on porcine skin from a single miniature pig and human skin from three donors. Skin temperature was maintained at either 32 ± 1°C or 42 ± 1°C to mimic normal and elevated skin temperature conditions, respectively. IVPT studies on porcine and human skin were able to demonstrate heat-induced enhancement in flux and cumulative amount of drug permeated from the four diclofenac products. The pivotal data showed the most significant heat-induced enhancement for the solution, followed by the patch and two gels in decreasing order of significance based on p values. Diclofenac solution showed the highest flux and cumulative amount permeated at both baseline and elevated skin temperature compared to the patch and gels. The studies demonstrated that exposure to heat can alter drug permeation from topical formulations, but the increased levels are not expected to lead to systemic concentrations that are of concern. Formulation design and excipients can influence drug permeation at elevated skin temperature.

A prospective study comparing the FLIR ONE with laser Doppler imaging in the assessment of burn depth by a tertiary burns unit in the United Kingdom.

Introduction:Laser Doppler imaging (LDI) is the ‘gold standard’ tool for the assessment of burn depth. However, it is costly. The FLIR ONE is a novel, mobile-attached, thermal imaging camera used to assess burn wound temperature. This study compares the FLIR ONE and LDI in assessing burn depth and predicting healing times.Methods:Forty-five adult patients with burn wounds, presenting at 1–5 days, were imaged with the FLIR ONE and LDI. Infected, chemical and electrical burns were excluded. Healing potential was determined by comparing wound and normal skin temperature for the FLIR ONE and blood flow changes with the LDI. Healing potential was categorised into wounds healing in less than and over 21 days. Pearson’s test was used to determine the correlation between changes in wound temperature and healing potential.Results:Percent total body surface area (%TBSA) was in the range of 0.5–45. FLIR demonstrated a sensitivity of 66.67% and specificity of 76.67% in predicting healing within 21 days, while LDI demonstrated a sensitivity of 93.33% and specificity of 40%. The FLIR ONE showed a significant difference in the mean temperature changes between burns that healed in less than (0.1933 ± 0.3554) and over 21 days (–1 ± 0.4329) (P = 0.04904). Pearson’s test showed a significant correlation between the difference in wound and normal skin temperature with healing times (P = 0.04517).Conclusion:The inexpensive FLIR ONE shows a significant correlation between changes in wound temperature and healing times. It is useful in predicting healing within 21 days. However, evaporative cooling at the wound surface can lead to overprediction of healing times and overtreatment.Lay Summary Background Laser Doppler imaging is currently the main tool for burn depth assessment. It works by analysing the blood flow in a burn wound. Based on these findings, it can predict the depth of the burn injury and predict if it will heal in less than or over 21 days. The main problem is that it is costly. The FLIR ONE is a novel, mobile-attached, thermal imaging camera. It can be used to assess burn depth by comparing the temperature of the burn wound to the surrounding normal skin. This information can then be used to predict healing times into less than and over 21 days. The issue being explored The usefulness of the FLIR ONE in assessing burn depth and predicting healing time when compared to the LDI. How was the work conducted? Forty-five adult patients who sustained a burn injury within the last five days were imaged with both the FLIR ONE and LDI. Those with infected, electrical or chemical burns were excluded. Healing potential was determined by comparing the temperature of the burn wound with normal skin for the FLIR ONE and by changes in wound blood flow with the LDI. Healing potential was categorised into wounds healing in less than and over 21 days. The correlation between the temperature changes of the burn wound and healing time was evaluated for the FLIR ONE. What we learned from the study This study was able to demonstrate that the FLIR ONE showed a significant correlation between the temperature difference between the burn wound and normal skin with healing times. When compared with the LDI, the FLIR ONE was useful in predicting if a burn wound will heal in less than 21 days. The FLIR ONE has advantages over the LDI, it is low cost, portable and produces instantaneous images. Ultimately, this developing technology may increase access to higher standard burn care in centres where LDI is not affordable.

Effect of Mild Hyperthermia on Transdermal Absorption of Nicotine from Patches.

Application of heat (hyperthermic conditions) on skin is known to enhance drug transfer and facilitate skin penetration of molecules. The aim of this work was to study the effect of hyperthermia on the drug release and skin permeation from nicotine transdermal patches. The drug release and skin permeation were characterized by in vitro release test and in vitro permeation test. The temperature was maintained at 32°C as control (simulating normal physiological skin temperature) and 42°C as hyperthermia condition. The in vitro release test was carried out using USP apparatus 5-Paddle over disk method for a transdermal patch. Skin permeation study was carried out across porcine skin using the flow through cells (PermeGear, Inc.) with an active diffusion area of 0.94cm2. Mechanistic studies (parameters such as partition coefficient, TEWL and electrical resistivity) were also performed to understand the mechanisms involved in determining the influence of hyperthermia on drug delivery from transdermal patches of nicotine. The rate and extent of drug release from nicotine patch was not significantly different at two temperatures (Cumulative release after 12h was 43.99 ± 3.29% at 32°C and 53.70 ± 5.14% at 42°C). Whereas, in case of in vitro permeation studies, the nicotine transdermal permeation flux for patch was threefold higher at 42°C (100.1 ± 14.83μg/cm2/h) than at 32°C (33.3 ± 14.83μg/cm2/h). The mechanistic studies revealed that the predominant mechanism of enhancement of drug permeation by hyperthermia condition is by the way of increasing the skin permeability. There is a potential concern of dumping of higher dose of nicotine via transdermal route.

Thermal photodynamic therapy increases apoptosis and reactive oxygen species generation in cutaneous and mucosal squamous cell carcinoma cells

Thermal photodynamic therapy (PDT) is an emerging modality to optimize treatment of pre-cancerous squamous cell carcinoma (SCC) lesions, known as actinic keratoses. Thermal PDT involves heating the tissue, skin, or mucosa above normal skin temperature during 5-aminolevulinic (5-ALA) incubation and irradiating with blue light, which leads to cell apoptosis and reactive oxygen species (ROS) generation. To our knowledge, thermal PDT has not been studied for the treatment of cutaneous or mucosal SCC. We incubated two SCC cell lines with 5-ALA for 30 minutes at temperatures between 21 °C and 42 °C and then irradiated cells with 1000 seconds of blue light. We measured changes in apoptosis, necrosis, and ROS. At 36 °C, there was a dose-dependent increase in apoptosis and ROS generation. Thermal incubation of 5-ALA at 39° and 42 °C followed by blue light increased cell apoptosis and ROS generation compared to untreated control samples incubated at the same temperatures. Thermal PDT may represent a new treatment option for cutaneous and mucosal SCC cancer. Thermal PDT is associated with an increase in SCC cellular apoptosis and is associated with an upregulation in ROS. Clinical trials are required to determine optimal thermal PDT treatment parameters and efficacy for cutaneous and mucosal SCC.

Differential effects of radiant and mechanically applied thermal stimuli on human C-tactile afferent firing patterns.

C-tactile (CT) afferents respond to gentle tactile stimulation, but only a handful of studies in humans and animals have investigated whether their firing is modified by temperature. We describe the effects of radiant thermal stimuli, and of stationary and very slowly moving mechanothermal stimuli, on CT afferent responses. We find that CT afferents are primarily mechanoreceptors, as they fired little during radiant thermal stimuli, but they exhibited different patterns of firing during combined mechano-cool stimulation compared with warming. CTs fired optimally to gentle, very slowly moving, or stationary mechanothermal stimuli delivered at neutral temperature (~32°C, normal skin temperature), but they responded with fewer spikes (median 67% decrease) and at significantly lower rates (47% decrease) during warm (~42°C) tactile stimuli. During cool tactile stimuli (~18°C), their mean instantaneous firing frequency significantly decreased by 35%, but they often fired a barrage of afterdischarge spikes at a low frequency (~5 Hz) that outlasted the mechanical stimulus. These effects were observed under a variety of stimulus conditions, including during stationary and slowly moving touch (0.1 cm/s), and we complemented these tactile approaches using a combined electrical-thermal stimulation experiment where we found a suppression of spiking during warming. Overall, CT afferents are exquisitely sensitive to tactile events, and we show that their firing is modulated with touch temperatures above and below neutral skin temperature. Warm touch consistently decreased their propensity to fire, whereas cool touch produced lower firing rates but afterdischarge spiking. NEW & NOTEWORTHY C-tactile (CT) afferents are thought to underpin pleasant touch, and previous work has shown that they respond optimally to a slow caress delivered at typical (neutral) skin temperature. Here, we show that, although CTs are primarily mechanoreceptive afferents, they are modified by temperature: warm touch decreases their firing, whereas cool touch produces lower firing rates but long-lasting spiking, frequently seen as afterdischarges. This has implications for the encoding of affective sensory events in human skin.

Clinical application of ultrasound guided Fogarty balloon catheter in arterial crisis

To explore the effectiveness of arterial crisis after replantation of limb treated by ultrasound guided Fogarty balloon catheter. Between January 2012 and July 2016, 27 patients suffered from arterial crisis after replantation of limb were treated with ultrasound guided Fogarty balloon catheter combined with thrombolytic anticoagulant. There were 18 males and 9 females with the age of 19-51 years (mean, 32 years). The limb mutilation position was at knee joint in 3 cases, lower limb in 9 cases, ankle joint in 6 cases, elbow joint in 2 cases, forearm in 4 cases, and wrist joint in 3 cases. The arterial crisis happened at 2.5-18 hours (mean, 7.5 hours) after limb replantation surgery. Color doppler ultrasonography was used to diagnose the arterial thrombosis, finally the anastomotic thrombosis were found in 16 cases, non-anastomotic thrombosis in 7 cases, and combined thrombosis in 4 cases. All the thrombosis were deteced in the arteries with the length of 0.8-3.9 cm. No complication such as vascular perforation, rupture, air embolism, thromboembolism, wound infection, or sepsis happened after operation. Arterial crisis occurred again in 3 cases at 1.5-13.5 hours after limb replantation and treated by arterial exploration, 1 case was treated successfully; 2 cases had arterial occlusion and partial necrosis of limb, and got amputation treatment at last. The rest 24 cases survived with the incision healing by first stage. In the 24 cases, 1 case suffered from acute myonephropathic metabolic syndrome and corrected after hemodialysis; 1 case suffered from acute liver functional damage and corrected by comprehensive treatment of internal medicine. The 24 patients were followed up 7-38 months (mean, 11 months). At last follow-up, blood supply of the limb was good with normal skin temperature and improved sense of feeling, activity, and swelling. According to Chinese Medical Association of hand surgery to the upper extremity function assessment standard, the results were excellent in 12 cases, good in 8 cases, and fair in 4 cases with an excellent and good rate of 83.3%. Ultrasound guided Fogarty balloon catheter treatment of posterior replantation of arterial crisis can accurately locate the thrombosis, get the thrombus fast and invasive minimally to avoid the blind and repeated thrombectomy, and obtain certain effectiveness.

One Dimensional Transient State Finite Element Model to Study Thermal Variations due to Transient Vasoconstriction followed by Persistent Vasodilation during Inflammation in Surgical Wound of Peripheral Tissues of Human Limb

Objectives: This paper compares theoretically the thermal variations in normal tissues, clean surgical wound and contaminated surgical wound in peripheral tissues of human arm and leg during inflammatory phase of healing. Methods/Statistical Analysis: One dimensional finite element model is developed using Bio-heat equation.Values of arterial blood temperature, core body temperature and heat transfer coefficient have been revised. During inflammation blood perfusion rate and metabolic heat generation rate are considered linearly dependent on temperature and spatial coordinate, and exponentially dependent on time.The effect of vasodilation and effect of rate at which vascular changes occur, on temperature profiles,is investigated by varying value of linear coefficient of temperature dependence and coefficient of time variable respectively. Findings: A computer programme in MATLAB is developed to simulate the results. Skin surface temperature in normal tissue are simulated and validated from published experimental data. Maximum blood perfusion rate at maximum vasodilation calculated theoretically is validated with the published experimental data. Temperature difference in contaminated wound and normal tissue are simulated and validated with the published experimental data. Improvements/Applications: Normal skin temperature and thermal variations during vasodilation are modelled well by revising the values of parameters mentioned above and considering temperature dependent parameters.This information may be useful to biomedical scientists in development of treatment regimen for surgical wounds.

One Dimensional Transient State Finite Element Model to Study Thermal Variations due to Transient Vasoconstriction followed by Persistent Vasodilation during Inflammation in Surgical Wound of Peripheral Tissues of Human Limb

Objectives: This paper compares theoretically the thermal variations in normal tissues, clean surgical wound and contaminated surgical wound in peripheral tissues of human arm and leg during inflammatory phase of healing. Methods/ Statistical Analysis: One dimensional finite element model is developed using Bio-heat equation.Values of arterial blood temperature, core body temperature and heat transfer coefficient have been revised. During inflammation blood perfusion rate and metabolic heat generation rate are considered linearly dependent on temperature and spatial coordinate, and exponentially dependent on time.The effect of vasodilation and effect of rate at which vascular changes occur, on temperature profiles,is investigated by varying value of linear coefficient of temperature dependence and coefficient of time variable respectively. Findings: A computer programme in MATLAB is developed to simulate the results. Skin surface temperature in normal tissue are simulated and validated from published experimental data. Maximum blood perfusion rate at maximum vasodilation calculated theoretically is validated with the published experimental data. Temperature difference in contaminated wound and normal tissue are simulated and validated with the published experimental data. Improvements/Applications: Normal skin temperature and thermal variations during vasodilation are modelled well by revising the values of parameters mentioned above and considering temperature dependent parameters.This information may be useful to biomedical scientists in development of treatment regimen for surgical wounds. Keywords: Finite Element Technique ,Non-linear Partial Differential Equation,, Temperature Dependent Blood Perfusion Rate, Temperature Dependent Metabolic Heat Generation Rate, Thermal Variations in Peripheral Tissues of Human Limb, Vasodilation

Evaporation of decamethylcyclopentasiloxane (D5) from selected cosmetic products: Implications for consumer exposure modeling

Consumer exposure to leave-on cosmetics and personal care products (C&PCPs) ingredients of low or moderate volatility is often assumed to occur primarily via dermal absorption. In reality they may volatilize from skin and represent a significant source for inhalation exposure. Often, evaporation rates of pure substances from inert surfaces are used as a surrogate for evaporation from more complex product matrices. Also the influence of partitioning to skin is neglected and the resulting inaccuracies are not known. In this paper we describe a novel approach for measuring chemical evaporation rates from C&PCPs under realistic consumer exposure conditions. Series of experiments were carried out in a custom-made ventilated chamber fitted with a vapor trap to study the disposition of a volatile cosmetic ingredient, decamethylcyclopentasiloxane (D5), after its topical application on either aluminum foil or porcine skin in vitro. Single doses were applied neat and in commercial deodorant and face cream formulations at normal room (23°C) and skin temperature (32°C). The condition-specific evaporation rates were determined as the chemical mass loss per unit surface area at different time intervals over 1–1.25h post-dose. Product weight loss was monitored gravimetrically and the residual D5 concentrations were analyzed with GC/FID. The release of D5 from exposed surfaces of aluminum occurred very fast with mean rates of 0.029mgcm−2min−1 and 0.060mgcm−2min−1 at 23°C and 32°C, respectively. Statistical analysis of experimental data confirmed a significant effect of cosmetic formulations on the evaporation of D5 with the largest effect (2-fold decrease of the evaporation rate) observed for the neat face cream pair at 32°C. The developed approach explicitly considers the initial penetration and evaporation of a substance from the Stratum Corneum and has the potential for application in dermal exposure modeling, product emission tests and the formulation of C&PCPs.

Facial Paralysis - Thermal Patterns

Facial paralysis is a common affliction for the Rehabilitation Medicine practitioner. This type of paralysis is a very disabling condition. The lost sensation and muscle control in the territory of the facial nerve can cause difficulty in speech, swallowing, closing the eye (it can cause blindness if not tended carefully), it ca also cause vertigo (sometimes it’s so severe that the patient is unable to stand or walk) or the loss of taste in the anterior two thirds of the tongue. In healthy individuals the skin temperature distribution is symmetric. Lesions of the facial nerve are associated with an alteration of the normal skin temperature pattern. Infrared thermography is a valuable auxiliary tool for differential diagnosis, as it objectivizes the infrared thermal distribution on the facial skin.

Clinician's Commentary on Bech et al.(1).

Clinician's Commentary on Bech et al.(1).

Contactfree Infrared Thermography for the Determining “Normal Skin Temperature” in 50 Healthy Probands

Definition of “normal temperature” is controversial in many text books on dermatology and physiology and depends on many factors. Thermographic imaging of the hands was performed in 50 healthy volunteers on four different days with an interval of 48-72 hours summing up to a total of 200 measurements. Infrared thermograms were gathered at defined points in each person after an acclimatization period of 30 minutes under standardized conditions according to the recommendations of the American Academy of Thermology. Despite of an acclimatization period of 30 minutes a decrease of temperature in the monitored area independent of gender could be observed. Initial surface temperature after the acclimatization period in these healthy probands ranged from 25.2 to 33.8°C (31.6 ± 2.1°C, median 32.2°C). Severe intra- and interindividual temperature differences could be detected despite standardized room conditions. Skin temperature varies greatly between and within individuals. Contactfree infrared thermography may improve detection of areas with altered perfusion if a symmetrical scan is performed. Nevertheless, screening patients on their general surface temperature does not provide any beneficial information in diagnosing or differentiating diseases unless a certain pathology is suspected in a particular area. DOI: http://dx.doi.org/10.18073/2358-4696/pajmt.v1n1p43-49