Differences In Skin Thickness Research Articles

The Assessment of the Long-Term Impact of Radiotherapy on Biophysical Skin Properties in Patients after Head and Neck Cancer.

Background and Objectives: Chronic radiotherapy-induced skin injury (cRISI) is an irreversible and progressive condition that can significantly impact a patient's quality of life. Despite the limited literature available on the assessment of the epidermal barrier in cRISI, there is a consensus that appropriate skincare, including the use of emollients, is the primary therapeutic approach for this group of patients. The aim of this study was to evaluate the biophysical properties of the skin during the late period (at least 90 days) following radiation therapy (RT) for head and neck cancer. Materials and Methods: This was a single-center prospective non-randomized study. It involved the analysis of 16 adult patients with head and neck cancer who underwent RT at the Greater Poland Cancer Center, along with 15 healthy volunteers. The study and control groups were matched for gender and age (p = 0.51). Clinical assessment, based on the LENT-SOMA scale, was conducted for all patients. Evaluation of the skin's biophysical properties included: an analysis of transepidermal water loss (TEWL), stratum corneum hydration (SCH), and skin visualization using high-frequency ultrasonography (HF-USG). Results: A significantly higher TEWL was observed in the irradiated area compared to the control area in the study group (p = 0.004). However, there was no statistically significant difference in SCH (p = 0.073). Additionally, no significant difference was observed in the values of TEWL and SCH in the irradiated area between the group of patients with and without clinically obvious RISI (p = 0.192 and p = 0.415, respectively). The skin thickness of the irradiated area, assessed by HF-USG, did not differ significantly from the skin thickness of the control area (p = 0.638). Furthermore, no difference in skin thickness was observed in patients with clinical features of cRISI in the irradiated and control areas (p = 0.345). The mean time after RT was 6.1 years. Conclusions: This study marks the first demonstration of epidermal barrier damage in patients in the long term following RT for head and neck cancer. The impairment of the epidermal barrier was observed independently of evident cRISI features. This observation underscores the necessity to recommend appropriate skin care, including the use of emollients, for all patients following RT. We also suggest that HF-USG examination is generally inconclusive in determining the degree of skin damage in the late period after RT.

Evaluating Skin Involvement in Systemic Sclerosis Using High-Frequency Ultrasound and Virtual Touch Tissue Imaging

ObjectiveThis study aimed to explore the diagnostic significance of high-frequency ultrasound combined with visual touch tissue imaging quantification (VTIQ) in the diagnosis and management of systemic sclerosis (SSc). MethodsPatients diagnosed with SSc and normal volunteers were recruited and divided into an experimental group and a control group, with 30 cases in each group, respectively. The skin thickness at six sites was assessed using high-frequency ultrasound, and the shear wave velocity (SWV) was determined using the VTIQ method. The differences in skin thickness and SWV between the experimental group and the control group were compared and a receiver operating characteristic (ROC) curve was plotted. The value of high-frequency ultrasound, VTIQ, and high-frequency ultrasound combined with VTIQ for evaluating skin involvement in SSc was determined. ResultsThe difference in SWV sum at six sites and the thickness sum was statistically significant (all p = 0.000 < 0.05) from that of the control group, and there was a strong association between the SWV sum, thickness sum, and Rodnan skin score at the six sites in the experimental group (p = 0.000, r = 0.726; p = 0.000, r = 0.679). Based on the ROC curve, the area under the curve (AUC) for high-frequency ultrasound examination was 0.789. The AUC for VTIQ examination was 0.893, while the AUC for high-frequency ultrasound combined with VTIQ examination was 0.923. The combined examination method showed the highest AUC, indicating the best diagnostic performance. ConclusionThe integration of high-frequency ultrasound and VTIQ provides a quantitative approach for assessing the extent of skin involvement in SSc patients, offering valuable insights for clinical diagnosis and treatment purposes.

Impact of nuclear structure on longitudinal flow decorrelations in high-energy isobar collisions

Fluctuations of harmonic flow along pseudorapidity, known as flow decorrelations, are an important probe of the initial state geometry of the quark-gluon plasma. The flow decorrelations are shown to be sensitive to the collective structure of the colliding nuclei, as revealed clearly by comparing 96Ru+96Ru collisions and 96Zr+96Zr collisions, which have different nuclear structures. The flow decorrelations in central collisions are mostly sensitive to nuclear deformations, while those in the mid-central collisions are primarily sensitive to differences in skin thickness between 96Ru and 96Zr. Longitudinal flow decorrelations in heavy-ion collisions are a new tool to probe the structure of colliding nuclei.

Separating the Impact of Nuclear Skin and Nuclear Deformation in High-Energy Isobar Collisions.

Bulk nuclear structure properties, such as radii and deformations, leave distinct signatures in the final state of relativistic heavy-ion collisions. Isobaric collisions offer an easy route to establish explicit connections between the colliding nuclei's structure and the observable outcomes. Here, we investigate the effects of nuclear skin thickness and nuclear deformations on the elliptic flow (v_{2}) and its fluctuations in high-energy ^{96}Ru+^{96}Ru and ^{96}Zr+^{96}Zr collisions. Our findings reveal that the difference in skin thickness between these isobars only influences the inherent ellipticity of the collision systems, v_{2}^{rp}. In contrast, differences in nuclear deformations solely impact the fluctuations of v_{2} around v_{2}^{rp}. Hence, we have identified a data-driven method to disentangle the effects of nuclear skin and nuclear deformations, marking a significant step toward assessing the consistency of nuclear phenomena across energy scales.

Resolving trapdoor phenomenon without secondary procedure after forehead flap on medial canthal region.

Herein, we present a case of basal cell carcinoma in a 59-yearold woman. It presented with painless itchy, black, gradually enlarged patches which were easily bled under her left eye since three years ago. A dermatological examination of the left medial canthus region obtained hyperpigmented plaques (2x0.8x0.1 cm) with uneven skin texture, irregular borders, and erosion on the center of the lesion. We performed forehead flap technique surgery followed by eight-month monitoring, resulting in a satisfying outcome in both function and appearance. The thinning technique and adjusting the flap size from the forehead area to the medial canthus should be as thin as possible to avoid differences in skin thickness and post-reconstruction hypertrophic scars. A bulging appears on the surgical site a month after the procedure, known as the trapdoor phenomenon, on the 8th month of followup, the trapdoor phenomenon disappeared.

Optical bone densitometry insensitive to skin thickness.

Skin thickness, including the adipose layer, which varies from individual to individual, affects the bone density measurement using light. In this study, we proposed a method to measure skin thickness using light and to correct the bias caused by differences in skin thickness and verified the proposed method by experiments using a phantom. We measured simulated skin of different thicknesses and bovine trabecular bone of different bone mineral densities (BMDs) using an optical system consisting of lasers of 850 and 515nm wavelengths, lenses, and slits. Although the slope of the light intensity distribution formed on the surface of the material when irradiated by the 850nm laser is affected by the thickness of the skin phantom. The difference of the intensity distribution peaks (δy) between the 850 and 515nm lasers was strongly correlated with the thickness of the skin phantom. The coefficient of determination between the measurements and the BMD was improved by correcting the 850nm laser measurements with δy. This result suggests that the method is applicable to optical bone densitometry, which is insensitive to differences in skin thickness.

An analysis of skin thickness in the Dezhou donkey population and identification of candidate genes by RNA-seq.

The aim of the present study was to analyze the main factors that have a significant impact on skin thickness, and to further identify the genes and signaling pathways regulating skin growth by RNA-seq in Dezhou donkeys. Skin samples from different body regions of 15 slaughtered donkeys were obtained to study variations in skin thickness over the bodies. Skin thickness data for another 514 donkeys was obtained by minimally invasive skin sampling from the back, and measurements of the donkeys' body size traits and pedigree data were also collected. These data were used to analyze changes in skin thickness and estimate genetic parameters. In addition, transcriptomic analysis was conducted on the skin tissues of individuals from two groups with significant differences in skin thickness. Our results showed that skin thickness over the bodies ranged from 1.08 to 4.36mm. The skin from the back was the thickest and had the highest correlation with that of other regions of the body. The skin thickness decreased from the back to the side of the ventral abdomen, and the skin thickness on the limbs increased from the proximal end to the distal end. The results also showed that the skin from the same body regions of jacks was thicker than that of jennies in the same age group. The skin thickness of jennies increased from birth to the age of 2 and then clearly decreased after 2years of age. The estimated heritability of skin thickness was 0.15, and the genetic correlations between skin thickness and body size traits were negligible. Transcriptome analysis showed that the thick-skin group had 65 up-regulated genes and 38 down-regulated genes compared with the thin-skin group. The differentially expressed genes were highly enriched in epidermal development and cell adhesion molecule signaling pathways. We identified the candidate genes responsible for variations in skin thickness in the Dezhou donkey, including KRT10, KRT1, CLDN9, MHCII and MMP28. These results contribute to a better understanding of the growth and development of donkey skin, reveal the molecular mechanism responsible for donkey skin thickness and suggest directions for genetic selection in the Dezhou donkey population.

Skin barrier before and after topical Adipose Stem Cell-Conditioned Medium (ASC-CM) treatment in photoaging

Background: Photoaging is a type of aging mainly caused by ultraviolet irradiation. The skin barrier is affected in photoaging and it will result in coarseness, roughness and dry skin. It is probably because Ultraviolet (UV) affects the extracellular matrix in the skin. Adipose Stem Cell-Conditioned Medium (ASC-CM), which contains many growth factors, becomes a potential agent as a novel anti-photoaging treatment by repairing the skin barrier. This study aims to evaluate the skin barrier function before and after treatment with ASC-CM in photoaging skin by evaluating changes in Transepidermal Water Loss (TEWL) and skinfold thickness.Methods: A true experimental study was conducted among 28 male Wistar rats aged 10-12 weeks. They were acclimated for 1 week and randomly divided into 4 groups: UV irradiated group with topical ASC-CM (Group P1); UV irradiated group with topical vehicle only (Group P2); only topical ASC-CM, non-UV irradiated (Group P3), and non-UV irradiated and no topical treatment (Group P0). The ASC-CM was given twice a day for four weeks and the total irradiance dose for 6 weeks was 4,2 J/cm2. Data were analyzed using SPSS version 20 for Windows.Results: There was a statistically significant difference of TEWL between pre-and post-treatment in group P3 (p=0.043) and P0 (p=0.018). In addition, a statistically significant difference in skin thickness was also found between pre-and post-treatment in group P2 (p=0.005) and P3 (p=0.003). There was a statistically significant difference in skin thickness post-treatment (p=0.000); however, there was no statistically significant difference of TEWL post-treatment by One-Way ANOVA test (p=0.138).Conclusion: ASC-CM could be a potential option for photoaging skin based on the TEWL and skin thickness evaluation. However, a longer study period was needed to know the further effect of ASC-CM.

Low-intensity ultrasound combined with allogenic adipose-derived mesenchymal stem cells (AdMSCs) in radiation-induced skin injury treatment

Mesenchymal stem cells are mechano-sensitive cells with the potential to restore the function of damaged tissues. Low-intensity ultrasound has been increasingly considered as a bioactive therapeutic apparatus. Optimizing transplantation conditions is a critical aim for radiation-induced skin tissue injury. Therefore, the therapeutic function of adipose-derived mesenchymal stem cells to ultrasound stimulus was examined based on the mechanical index (MI). Mesenchymal stem cells were isolated from the adipose tissues of mature guinea pigs. An ultrasound system (US) was constructed with a 40 kHz frequency. The radiation-induced skin injury model was produced on the abdominal skin of guinea pigs by 60 Gy of radiation. Then, they were divided to 7 groups (n = 42): control, sham, US (MI = 0.7), AdMSCs injection, US AdMSCs (AdMSCs, under US with MI = 0.2), AdMSCs + US (AdMSCs transplantation and US with MI = 0.7) and US AdMSCs + US (combining the last two groups). The homing of stem cells was verified with fluorescence imaging. The groups were followed with serial photography, ultrasound imaging, tensiometry, and histology. The thickness of the skin was analyzed. Functional changes in skin tissue were evaluated with Young’s modulus (kPa). One-way ANOVA tests were performed to analyze differences between treatment protocols (p < 0.05). The results of Kumar’s score showed that radiation injury was significantly lower in the treatment groups of US AdMSCs and US AdMSCs + US than other groups after 14 days (p < 0.05). There was a significant difference in skin thickness between treatment groups with control, sham, and US groups after 60 Gy radiation and were closer to the thickness of healthy skin. Young’s modulus in US AdMSCs + US, US AdMSCs, and AdMSCs + US groups demonstrated a significant difference with the other groups (p < 0.05). Young’s modulus in US AdMSCs + US and US AdMSCs treatment groups were closer to Young’s modulus of the healthy skin. The histological results confirmed the improvement of acute radiation damage in the combined treatment method, especially in US AdMSCs + US and US AdMSCs groups with increasing the epithelialization and formation of collagen. An ultrasonic treatment plan based on a mechanical index of the target medium could be used to enhance stem cell therapy.

Photodynamic Therapy Using HMME for Port-Wine Stains: Clinical Effectiveness and Sonographic Appearance.

This study aims at exploring the clinical efficacy and sonographic changes of photodynamic therapy (PDT) using Hematoporphyrin Monomethyl Ether (HMME) for the treatment of port-wine stains (PWS). Forty-five patients with PWS were recruited between March 2017 and June 2018 from the Department of Dermatology of The Third Affiliated Hospital of Soochow University. Five cases were of the pink type, thirty-nine cases were of the purple-red type, and one case was of the thickened type. All patients received three treatment sessions of PDT. After covering normal skin outside the treated area, patients received an intravenous injection of 5 mg/kg HMME within 20 minutes. The affected areas were exposed to a 532 nm LED light and were kept vertically at a distance of 10 cm. The irradiation energy density was set between 80 and 110 J/cm2 in 15-minute sessions. Intermittent power density adjustment was performed at a rate of 5 mW/cm2, and the treatment was withheld when the endpoint reaction appeared. Three follow-ups were performed before and after treatment, respectively, and the efficacy, thickness, and density of skin before and after treatment were evaluated with high-frequency ultrasound. The overall efficacy rate was 97.78% in forty-five cases after treatment for three sessions. Efficacy was related to age (P = 0.029) and lesion severity (P < 0.001). There were significant differences in the efficacy between the groups of <18 years old, 18-29 years old, and >29 years old (P = 0.029). A marked decrease in the numbers of distorted enlarged blood vessels per unit of the lesion was observed under high-frequency ultrasound. There were significant differences in skin thickness and skin density before and after treatment (F = 14.528, 5.428, P < 0.001). The swelling was reported to varying degrees in the treated areas in 23 patients with cheek lesion and in 6 frontal lesions. Hyperpigmentation after inflammation was observed in four patients that faded spontaneously after two months. In conclusion, photodynamic therapy for the treatment of PWS using HMME is effective and safe with few adverse reactions. Moreover, monitoring the changes in skin thickness and density of lesion tissue using high-frequency ultrasound can objectively evaluate the clinical efficacy of HMME photodynamic therapy and provide the basis for the formulation of individualized photodynamic therapy.

Quantitative assessment of temporal skin elasticity using shear wave elastography in pediatric cochlear implant users

ObjectiveTo evaluate temporal skin thicknesses and stiffness values using shear wave elastography (SWE) in asymptomatic pediatric patients who underwent cochlear implantation. Subjects and methodsSixty-four deafened pediatric patients with unilateral cochlear implant (CI) who had no complications were enrolled. The age, sex, weight, height, body mass index (BMI), CI side, duration of CI use and CI device brand of all participants were noted. Temporal skin thickness and stiffness values were measured from implanted and contralateral unimplanted sides using SWE. ResultsThe mean skin thickness measurements of implanted and unimplanted sides were 11.87 ± 3.42 and 5.34 ± 1.56 mm, respectively. The mean skin stiffness measurements of implanted and unimplanted sides were 3.08 ± 0.7 and 1.29 ± 0.26 m/s, respectively. There were statistically significant differences in skin thickness and stiffness between implanted and unimplanted sides (P < .001, P < .001). The mean skin thickness and stiffness measurements did not differ among types of CI devices (P = .948, P = .362). Age had positive correlation with implanted (P < .001, P = .019) and unimplanted sides (P < .001, P < .001) skin thickness and stiffness. BMI had positive correlation with implanted (P < .001, P = .023) and unimplanted sides (P < .001, P < .001) skin thickness and stiffness. Duration of CI use had positive correlation with implanted side skin thickness (P < .001) and stiffness (P = .031). ConclusionTemporal skin thickness and stiffness increase after CI surgery. SWE has the potential to improve diagnostic accuracy, and our results may provide important data for evaluation of clinical entities that affect temporal skin structures.

Морфологічна характеристика шкіри та волосся клінічно здорових собак та котів

The article describes the histological characteristics of the skin of clinically healthy domestic dogs and cats, presents morphometric data on the thickness of the skin, layers of the epidermis, the area of the sebaceous glands and hair follicles; describes sexual and seasonal skin replacements in domestic dogs and cats, common in the east of Ukraine. The material for research is the skin of clinically healthy dogs and cats. Research method is histological. Punch-biopsy of skin fragments was performed in animals on the right from the middle of the lateral surface of the back. Fragments of skin after fixation in 10 % neutral formalin were examined by paraffin, followed by staining of slides with hematoxylin-eosin and by gelatin impregnation, staining with Sudan II, hematoxylin of Karachi. In horizontal and vertical skin sections, the following was investigated: the thickness of the epidermis, papillary and reticular layers, the length and width of the sweat and sebaceous glands, follicle of the hair, the location of hair bundles and the ratio of secondary follicles to primary ones. The histological characteristics of skin and derivatives in dogs and cats have been established. The information obtained from morphometric histostudies indicates significant fluctuations in the values in cats depending on the season; the difference in skin thickness in winter and summer reached 1407 μM and had the same parameters in females and males. The papillary and reticular layers of the dermis correlated with the total skin thickness as 53.9 and 60.3 % in winter and 45.4 and 38.7% in summer, respectively. Epidermal seasonal changes were less significant. The papillary layer of the skin of the domestic cat was more developed than the reticular layer, in contrast to the dogs. The area of the basal sebaceous glands in cats averaged 0.05 mm2 in summer and 0.013 mm2 in winter. In domestic dogs, skin thickness and hair density did not depend on seasonal changes, but on the sex of the animals; in females, the skin was on average 496 + 183 microns thick, and the density was not significantly higher than in males. The area of the sebaceous glands averaged 0,020 mm2 in dog, in cats 0.013 mm2 in summer and in winter – 0.05 mm2.

Identification Of Three Key Factors Contributing To The Aetiology Of Dark Circles By Clinical And Instrumental Assessments Of The Infraorbital Region.

BackgroundThe aetiology of infraorbital dark circles is complex and multi-factorial. The aim of this research was to measure and characterize dark circles and to determine the physiological changes associated with the occurrence of this aesthetically unpleasing issue.Materials and methodsClinical, photographic and instrumental assessments were performed on Caucasian skin to determine the most appropriate methodologies to measure dark circles, comparing different zones of the infraorbital region in subjects with and without dark circles. Exploratory studies were also carried out on African and Far East Asian skin, as well as on tracking the natural variation of dark circles over seven days in Caucasian subjects.ResultsUnder-eye dark circles in Caucasian subjects are characterized by significantly darker coloured skin and higher colour deviations between the dark circle region and surrounding areas of skin. Multispectral image analysis produced a higher melanin index in subjects with dark circles, suggesting hyperpigmentation in the affected area, in addition to a higher haemoglobin index. The higher haemoglobin index, combined with preliminary assessments of the vascular network by videocapillaroscopy, suggests there may be more dilated, thicker or increased numbers of capillaries in subjects with dark circles. Ultrasound analysis showed a significant difference in skin thickness between the two groups of subjects linking the appearance of dark circles to thinner skin under the eye. Many of these trends were also observed in African and Far East Asian skin. The results also showed intra-individual, intra-day and inter-day variability of dark circle intensity in subjects with Caucasian skin.ConclusionThree key physiological factors associated with the occurrence of infraorbital dark circles are hyperpigmentation, a tendency for more dilated, thicker or increased number of capillaries and thinner skin in the under-eye area. The combination of these three factors provides a robust indication of the presence of infraorbital dark circles.

Skin thickness measurements for optimal intradermal injections in children

BackgroundIn the context of precision medicine and in response to the highly needed capacity of rapid interventions towards new infectious diseases and pandemic outbreaks, intradermal immunization is gaining increased attention. However, the currently used Mantoux technique for ID injection is difficult to standardize and requires training, especially when used in children.To allow determining the maximum penetration depth and needle characteristics for the development of a platform of medical devices suited for intradermal injection, VAX-ID® and to ensure an accurate ID injection in children, the epidermal and dermal thickness at the proximal ventral and dorsal forearm (PVF & PDF) and at the deltoid region in children aged 8 weeks to 18 years were assessed. The lateral part of the upper leg was assessed as well in children aged 8 weeks to 2 years since it is a commonly used injection site in this population. Materials & MethodsMean thickness of the PVF, PDF, lateral part of the upper leg and deltoid were measured using high-frequency ultrasound. Association with gender, age and BMI was assessed using Mann-Whitney U Test, Spearman correlation and Wilcoxon Signed Ranks Test, respectively. ResultsResults showed an overall mean skin thickness of 0.99 mm (SD: 0.14 mm) at the PVF, 1.20 mm (SD: 0.17) at the PDF, 1.28 mm (SD: 0.16) at the lateral part of the upper leg and increasing to 1.32 mm (0.25) at the deltoid region. Age and BMI correlated significantly (p < 0.001) with skin thickness at all investigated body sites. Gender did not affect skin thickness in the investigated population. ConclusionSignificant differences in skin thickness at the PVF, PDF and deltoid region were seen according to age and BMI. An optimal needle length of 0.7 mm is advised to guarantee intradermal injection in children at all investigated injection sites. (NCT02727114).

The Efficacy of Hyaluronidase in Early Surgery of Nasal Bone Fracture.

A nasal bone fracture is one of the most common facial injuries and is often treated by closed reduction. Typically, 2 to 3 weeks are needed for patients to return to daily life because the operation is performed after swelling around the fracture site is reduced. This study aimed to investigate that hyaluronidase injection could reduce swelling, perform early operation and return to daily life accelerated.From January 2017 to December 2017, 181 patients with nasal bone fracture were analyzed. 60 patients underwent hyaluronidase injection and massage to reduce edema, then performed surgery within 2 to 4 days. The remaining patients were treated conservatively (massage alone); they then underwent surgery. Ultrasonography was used to measure changes in skin thickness, and the treatment duration, outcome, and patient satisfaction were compared.The duration from injury to surgery was short in the early operation group, and the period of recovery and return to ordinary life was significantly shorter than in the conventional group. The difference in skin thickness after hyaluronidase injection and massage was 0.8 mm in the early operation group; there was no significant difference in the conventional group. There was no statistically significant difference in satisfaction between the 2 groups, but the mean satisfaction was higher in the early operation group.In patients with nasal bone fracture after facial trauma, hyaluronidase injection, and massage led to reduced edema. This might improve patient satisfaction by allowing earlier operation and earlier return to daily life.

Examining the relationship between sexual dimorphism in skin anatomy and body size in the white-lipped treefrog, Litoria infrafrenata (Anura: Hylidae).

Amphibians transport water, oxygen, carbon dioxide and various ions (e.g. sodium and potassium) across their skin. This cutaneous permeability is thought to affect their ability to respond to environmental change and to play a role in global population declines. Sexual dimorphism of skin anatomy has been accepted in some species, but rejected in others. The species in which such dimorphism has been detected have all been sexually dimorphic in body size, with males that are smaller and have thinner skin. It is unclear whether this difference in skin thickness manifests a functional difference or if it is related to body size alone. Skin thickness (epidermis, spongy dermis, compact dermis and total thickness) was examined in males and females of the white-lipped treefrog (Litoria infrafrenata). Although the skin of males is absolutely thinner than that of females, this difference is explained by body size differences between the sexes. Overall, we conclude that skin thickness in male and female L. infrafrenata correlates with body size dimorphism and suggest that future studies on amphibian skin anatomy include measures of body size, test the ecological significance of sexually dimorphic skin anatomy and better document the prevalence of sexually dimorphic amphibian skin anatomy.

High frequency ultrasound to assess skin thickness in healthy adults

BackgroundIntradermal immunization is gaining increased attention due to multiple factors: (1) intradermal (ID) vaccination has been shown to induce improved immunogenicity compared to intramuscular (IM) vaccination; (2) ID vaccination has been shown to have a dose-sparing potential over IM leading to a reduced vaccine cost and an increased availability of vaccines worldwide. However, the currently used Mantoux technique for ID injection is difficult to standardize and requires training.The aim of the study was (1) to assess the epidermal and dermal thickness at the proximal ventral and dorsal forearm (PVF & PDF) and deltoid in adults aged 18–65years (2) to determine the maximum penetration depth and needle characteristics for the development of a platform of medical devices suited for intradermal injection, VAX-ID™. Materials and methodsMean thickness of the PVF, PDF and deltoid were measured using high-frequency ultrasound of healthy adults aged 18–65years. Correlation with gender, age and BMI was assessed using Mann-Whitney U Test, Spearman correlation and Wilcoxon Signed Ranks Test, respectively. ResultsResults showed an overall mean skin thickness of 1.19mm (0.65–1.55mm) at the PVF, 1.44mm (0.78–1.84mm) at the PDF, and 2.12mm (1,16–3.19mm) at the deltoid. Thickness of PVF & PDF and deltoid were significantly different for men vs women (pmean<0.001, <0.001, <0.001, and pmin<0.001, 0.012, <0.001, respectively). A significant association was found for age at the deltoid region (p<0.001). Skin thickness for PVF, PDF & deltoid was significantly associated to BMI (p<0.001). ConclusionSignificant differences in skin thickness were seen for the PVF, PDF and deltoid region for gender, and BMI. Age only influenced the skin thickness at deltoid region. A needle length of 1.0mm is best option for intradermal injection at the dorsal forearm (NCT02363465).

A custom tailored model to investigate skin penetration in porcine skin and its comparison with human skin

Reliable models for the determination of skin penetration and permeation are important for the development of new drugs and formulations. The intention of our study was to develop a skin penetration model which (1) is viable and well supplied with nutrients during the period of the experiment (2) is mimicking human skin as far as possible, but still is independent from the problems of supply and heterogeneity, (3) can give information about the penetration into different compartments of the skin and (4) considers specific inter-individual differences in skin thickness. In addition, it should be quick and inexpensive (5) and without ethical implications (6). Using a chemically divers set of four topically approved active pharmaceutical ingredients (APIs), namely diclofenac, metronidazole, tazarotene, and terbinafine, we demonstrated that the model allows reliable determination of drug concentrations in different layers of the viable epidermis and dermis. For APIs susceptible for skin metabolism, the extent of metabolic transformation in epidermis and dermis can be monitored. Furthermore, a high degree of accordance in the ability for discrimination of skin concentrations of the substances in different layers was found in models derived from porcine and human skin. Viability, proliferation, differentiation and markers for skin barrier function were surveyed in the model. This model, which we call ‘Hamburg model of skin penetration’ is particularly suited to support a rational ranking and selection of dermatological formulations within drug development projects.

The aesthetic unit principle of facial aging.

In youth, facial aesthetic units flow together without perceptible division. The face appears as a single dynamic structure with a smooth contour and very little if any shadowing between different anatomical regions. As one ages, facial aesthetic units slowly become distinct. This process may be a consequence of differences in skin thickness, composition of subcutaneous tissue, contour of the facial skeleton, and location of facial ligaments. Although the impact of aesthetic unit separation is clinically apparent, its fundamental role in perceived facial aging has not yet been defined empirically. To evaluate and define the effect of aesthetic unit separation on facial aging and to empirically validate the rationale for the blending of aesthetic units as a principle for facial rejuvenation. We prepared the photographs of 7 women for experimental evaluation of the presence or absence of facial aesthetic unit separation. Photographic stimuli were then presented to 24 naive observers in a blinded paired comparison. For each stimulus pair, observers were asked to select the facial photograph that they considered to be more youthful in appearance. Each stimulus was compared with all others. We calculated a preference score for the total number of times any photograph was chosen to be more youthful compared with all others. Paired t tests were used to compare the preference scores between the facial stimuli with and without aesthetic unit separation. We generated 4032 responses for analysis. Photographs without facial aesthetic unit separation were consistently judged to be more youthful than their aged original or modified counterparts, with mean preference scores of 0.66 and 0.33, respectively (P ≤ .047). When we selected the paired stimulus that directly compared one photograph with aesthetic unit separation with another with blended aesthetic units (2015 pairs), observers indicated that the photograph with the blended aesthetic unit was younger 95% of the time. Within-rater reliability was found to be very good (r = 0.88). Our data support the hypothesis that facial aesthetic unit separation influences perceived facial youthfulness among photographs of women. The presence of facial aesthetic unit separation results in a less youthful appearance. Based on these empirical data, the concept of facial aesthetic unit separation appears to play a significant role in perceived facial aging. NA.

The effects of transcranial direct current stimulation on conscious perception of sensory inputs from hand palm and dorsum.

Conscious perception of sensory signals depends in part on stimulus salience, relevance and topography. Letting aside differences at skin receptor level and afferent fibres, it is the CNS that makes a contextual selection of relevant sensory inputs. We hypothesized that subjective awareness (AW) of the time at which a sensory stimulus is perceived, a cortical function, may be differently modified by cortical stimulation, according to site and type of the stimulus. In 24 healthy volunteers, we examined the effects of transcranial direct current stimulation (tDCS) on the assessment of AW to heat pain or weak electrical stimuli applied to either the hand palm or dorsum. We also recorded the vertex-evoked potentials to the same stimuli. The assessment was done before, during and after cathodal or anodal tDCS over the parietal cortex contralateral to the hand receiving the stimuli. At baseline, AW to thermal stimuli was significantly longer for palm than for dorsum (P<0.01), while no differences between stimulation sites were observed for the electrical stimuli. Both cathodal and anodal tDCS caused a significant shortening of AW to thermal stimuli in the palm but not in the dorsum, and no effects on AW to electrical stimuli. Longer AW in the palm than in the dorsum may be attributable to differences in skin thickness. However, the selectivity of the effects of tDCS on AW to thermal stimulation of the glabrous skin reflects the specificity of CNS processing for site and type of sensory inputs.