Sampling time for different matrices in stress assessment of farmed Atlantic salmon post-smolt.

The sustainability of commercial aquaculture production depends critically on prioritizing fish welfare management. Besides monitoring welfare parameters such as fish behaviour and water quality, fish stress level can also provide a reliable measure of the welfare status of farmed fish. Cortisol and 5 of its metabolites (5ß-THF, cortisone, 5ß-DHE, 5ß-THE, ß-cortolone) were previously identified by the authors as suitable stress biomarkers of farmed Atlantic salmon. Based on this knowledge, the present study aimed to investigate the time-related dynamics of these metabolites in plasma, skin mucus, bile and faeces over a 72 h- period. The objective was to determine the optimal sampling time for each matrix and to understand the clearance pathway of these metabolites following stress. An experiment was carried out using a total of 90 Atlantic salmon with an average weight of 438 (±132) g. The average sea temperature was 6.9 °C during the experimental period. A control group of 10 fish was first collected before the remaining 80 fish were submitted to a stress of netting and subsequent relocation into two separate cages. From each of these two stress groups, 10 fish were sampled at 1 h, 2 h, 4 h, 6 h and 12 h, 24 h, 48 h, 72 h after the stress event respectively. The concentrations of cortisol and its metabolites were measured at each of the sampling timepoint. The results demonstrated that plasma cortisol metabolites reached the highest concentration 4 h after stress and remained elevated despite the slight decrease for the remaining timepoints. The peak level was observed at 12 h post-stress in skin mucus and 24 h in bile and faeces. The findings suggest that these timepoints are the optimal for sampling Atlantic salmon post-smolt following stressful events in acute stress studies. Furthermore, the results reveal that analysing cortisol and its metabolites, both in free and conjugated forms, rather than free cortisol provides greater flexibility as their concentrations are less affected by sampling procedure. This study confirms the appropriateness of skin mucus and faeces as less-invasive sample matrices for fish stress evaluation and provides a basis for further developing low invasive tools for monitoring the welfare of farmed salmonid.

Recent Advances in Skin-Interfaced Wearable Sweat Sensors: Opportunities for Equitable Personalized Medicine and Global Health Diagnostics.

Recent advances in skin-interfaced wearable sweat sensors enable the noninvasive, real-time monitoring of biochemical signals associated with health and wellness. These wearable platforms leverage microfluidic channels, biochemical sensors, and flexible electronics to enable the continuous analysis of sweat-based biomarkers such as electrolytes, metabolites, and hormones. As this field continues to mature, the potential of low-cost, continuous personalized health monitoring enabled by such wearable sensors holds significant promise for addressing some of the formidable obstacles to delivering comprehensive medical care in under-resourced settings. This Perspective highlights the transformative potential of wearable sweat sensing for providing equitable access to cutting-edge healthcare diagnostics, especially in remote or geographically isolated areas. It examines the current understanding of sweat composition as well as recent innovations in microfluidic device architectures and sensing strategies by showcasing emerging applications and opportunities for innovation. It concludes with a discussion on expanding the utility of wearable sweat sensors for clinically relevant health applications and opportunities for enabling equitable access to innovation to address existing health disparities.

Monitoring the skin structure during edema in vivo with spatially resolved diffuse reflectance spectroscopy.

Significance: Edema occurs in the course of various skin diseases. It manifests itself in changes in water concentrations in skin layers: dermis and hypodermis and their thicknesses. In medicine and cosmetology, objective tools are required to assess the skin's physiological parameters. The dynamics of edema and the skin of healthy volunteers were studied using spatially resolved diffuse reflectance spectroscopy (DRS) in conjunction with ultrasound (US). Aim: In this work, we have developed a method based on DRS with a spatial resolution (SR DRS), allowing us to simultaneously assess water content in the dermis, dermal thickness, and hypodermal thickness. Approach: An experimental investigation of histamine included edema using SR DRS under the control of US was conducted. An approach for skin parameter determination was studied and confirmed using Monte-Carlo simulation of diffuse reflectance spectra for a three-layered system with the varying dermis and hypodermis parameters. Results: It was shown that an interfiber distance of 1 mm yields a minimal relative error of water content determination in the dermis equal to 9.3%. The lowest error of hypodermal thickness estimation was achieved with the interfiber distance of 10 mm. Dermal thickness for a group of volunteers (7 participants, 21 measurement sites) was determined using SR DRS technique with an 8.3% error using machine learning approaches, taking measurements at multiple interfiber distances into account. Hypodermis thickness was determined with root mean squared error of 0.56 mm for the same group. Conclusions: This study demonstrates that measurement of the skin diffuse reflectance response at multiple distances makes it possible to determine the main parameters of the skin and will serve as the basis for the development and verification of an approach that works in a wide range of skin structure parameters.

Controllable-Swelling Microneedle-Assisted Ultrasensitive Paper Sensing Platforms for Personal Health Monitoring.

Microneedle (MN) patches, which allow the extraction of skin interstitial fluid (ISF) without a pain sensation, are powerful tools for minimally invasive biofluid sampling. Herein, an MN-assisted paper-based sensing platform that enables rapid and painless biofluid analysis with ultrasensitive molecular recognition capacity is developed. First, a controllable-swelling MN patch is constructed through the engineering of a poly(ethylene glycol) diacrylate/methacrylated hyaluronic acid hydrogel; it combines rapid, sufficient extraction of ISF with excellent structural integrity. Notably, the analyte molecules in the needles can be recovered into a moist cellulose paper through spontaneous diffusion. More importantly, the paper can be functionalized with enzymatic colorimetric reagents or a plasmonic array, enabling a desired detection capacity-for example, the use of paper-based surface-enhanced Raman spectroscopy sensors leads to label-free, trace detection (sub-ppb level) of a diverse set of molecules (cefazolin, nicotine, paraquat, methylene blue). Finally, nicotine is selected as a model drug to evaluate the painless monitoring of three human volunteers. The changes in the nicotine levels can be tracked, with the levels varying significantly in response to the metabolism of drug in different volunteers. This as-designed minimally invasive sensing system should open up new opportunities for precision medicine, especially for personal healthcare monitoring.

Systematic Review of Reflection Spectroscopy-Based Skin Carotenoid Assessment in Children.

Assessing children's skin carotenoid score (SCS) using reflection spectroscopy (RS) is a non-invasive, widely used method to approximate fruit and vegetable consumption (FVC). The aims for the current review were to (1) identify distributions of SCS across demographic groups, (2) identify potential non-dietary correlates for RS-based SCS, (3) summarize the validity and reliability of RS-based SCS assessment, and (4) conduct meta-analyses of studies examining the correlation between RS-based SCS with FVC. A literature search in eight databases in June 2021 resulted in 4880 citations and peer-reviewed publications written in English that investigated children's (2-10 years old) SCS using RS. We included 11 studies (intervention = 3, observational = 8). Potential covariates included weight status, ethnicity, seasonal variation, age, sex, and income. Studies reported criterion validity with children's FVC but not with plasma carotenoid. Additionally, no studies reported the reliability of RS-based SCS in children. Among the 726 children included in the meta-analysis, the correlation between RS-based SCS and FVC was r = 0.2 (p < 0.0001). RS-based SCS is a valid method to quantify skin carotenoids for children's FVC estimation with the potential for evaluating nutrition policies and interventions. However, future research should use standardized protocol for using RS and establish how RS-based SCS can translate to the amount of daily FVC in children.

Assessment of Brassica oleraceae L. (Brassicaceae) extract loaded ethosomal gel as a versatile vesicular carrier system for dermocosmetic application: A noninvasive split-faced study.

BACKGROUND: Plant extracts with rich ascorbic acid contents have greater antioxidant capability; extensively employed in skin beautifying products and protect skin from detrimental photodamaging environmental effects. Brassica oleraceae is having a substantial prospective toward cosmeceuticals owed by its profound activity against oxidation. AIM: To develop an effective topical ethosomal gel loaded with Brassica oleraceae leaves extract with significant antioxidant activity. METHODOLOGY: Valuation of antioxidant capability of plant leaves extract by 2,2-diphenyl-1-picrylhydrazyl (DPPH), and quantification of ascorbic acid was done through high performance liquid chromatography (HPLC). Ethosomes were prepared by cold method. Optimized suspension containing extract was incorporated in 2% Carbopol gel (test) along with extract solution (control). Noninvasive in vivo studies were performed for final product to assess its effects on skin by measuring melanin and erythema, sebum level, elasticity, moistness level, facial pores count and their area, skin wrinkling, and smoothness. RESULTS: Brassica oleraceae (red cabbage) leaves extract exhibited significant antioxidant potential (85.64 ± 1.28%) with 14.22 µg/g of ascorbic acid; expressed prominent cosmetic effects in terms of skin melanin, erythema, sebum, elasticity, hydration, facial pores, wrinkles, and smoothness when incorporated in ethosomes. ANOVA test also exhibited positive significant (p ≤ 0.05) effects on skin. CONCLUSION: Brassica oleraceae extract is a strong antioxidant with remarkable dermocosmetic benefits for skin.

Optimization of Enzymatic Degreasing of Sheep Leather for an Efficient Approach and Leather Quality Improvement Using Fractional Experimental Design.

Leather industry is making significant contributions to economic development. However, it is notably leading to a serious environmental pollution. Recently, the enzyme technology developments offer new opportunities for enzymatic application in leather making. In the present investigation, microbial lipases were studied and used in degreasing process of sheep leathers. In order to optimize degreasing efficiency, a fractional experimental design with four parameters (enzyme source, processing stage, lipase amount, and degreasing duration) was used. Lipases A from Aspergillus niger, F from Rhizopus oryzae, R from Penicillium roqueforti, and AY from Candida rugosa were selected for leather degreasing. Enzymatic treatment of sheep skin was carried out during two stages of beamhouse operations: deliming-bating and pickling. Obtained results showed that enzymatic degreasing efficiency is higher than those obtained with the conventional process. Lipase F from Rhizopus oryzae demonstrated the most interesting hydrolysis with yields of 58.3% and 37.2% for delimed and pickled skins, respectively. An enzymatic degreasing process on pickled leather using 0.125% (w/v) of lipase F during 3.5 h is the most promising for an industrial application with a 76.03 of degreasing efficiency. Results of the physico-mechanical tests of leathers having undergone enzymatic treatment complied with industry requirement. The enzymatic treatment may be carried out in the same conditions as employed in leather manufacturing process. Results suggested that the enzymatic degreasing improves the leather quality and reduces the use of chemical compounds and surfactant.

Nile tilapia skin (Oreochromis niloticus) for burn treatment: ultrastructural analysis and quantitative assessment of collagen.

Nile tilapia (Oreochromis niloticus) skin is a well-known biomaterial used as an occlusive dressing for burn treatment. It is also an inexpensive and important source of collagen. This study aims to describe the ultrastructural aspects of Nile tilapia skin, assess its collagen amount and organization, and compare quantitative methods of histochemical and immunohistochemical analysis (in all sterilization steps for use in burn dressings). One sample (0.5 × 0.5 cm) of ten different fish skins was divided in four groups: in natura skin (IN), chemical sterilization (CH), additional irradiation (30 kGy) (IR), and skins used in burn treatment (BT) to compare histochemical and immunohistochemical findings of collagen amount and describe ultrastructural aspects through scanning electron microscopy. The amount of type I collagen decreased during sterilization and clinical use owing to gradual reduction of immunostaining (anti-collagen-I) and decreasing fiber thickness of the collagen, when compared to type III (Picrosirius-red-polarized light). The collagen fibers were rearranged at each sterilization step, with a low collagen percentage and large structural disorganization in BT. The amount of type-I collagen was further reduced after BT (p < 0.05). Both the methods did not exhibit a quantified value difference (p = 0.247), and a positive correlation (r = 0.927; 95 % CI = 0.720-0.983) was observed between them, with concordance for collagen quantification in similar samples, presenting a low systematic error rate (Dalberg coefficient: 6.70). A significant amount of type-I collagen is still observed despite sterilization, although clinical application further reduces type I collagen. Its quantification can be performed both by immunohistochemistry and/or Picrosirius Red reliably.

Ecological Momentary Assessment of Alcohol Consumption and Its Concordance with Transdermal Alcohol Detection and Timeline Follow-Back Self-report Among Adults Experiencing Homelessness.

BACKGROUND: Studies of alcohol use presume valid assessment measures. To evaluate this presumption, we examined the concordance of alcohol use as measured by ecological momentary assessment (EMA) self-reports, transdermal alcohol concentration readings via the Secure Continuous Remote Alcohol Monitor (SCRAM), and retrospective self-reports via the Timeline Follow-Back (TLFB) among adults experiencing homelessness. METHODS: Forty-nine adults who reported alcohol misuse (mean age = 47, SD = 9; 57% Black; 82% men) were recruited from a homeless shelter. For 4 weeks, alcohol use was assessed: (i) 5 times or more per day by EMA, (ii) every 30 minutes by a SCRAM device worn on the ankle, and (iii) by TLFB for the past month at the end of the study period. There were 1,389 days of observations of alcohol use and alcohol use intensity for 49 participants. RESULTS: EMA and SCRAM alcohol use data agreed on 73% of days, with an interrater agreement Kappa = 0.46. A multilevel analysis of concordance of 3 measures for alcohol use yielded statistically significant correlations of 0.40 (day level) and 0.63 (person level) between EMA and SCRAM. Alcohol use was detected on 49, 38, and 33% of days by EMA, SCRAM, and TLFB, respectively. For alcohol use intensity, EMA and SCRAM resulted in statistically significant correlations of 0.46 (day level) and 0.78 (person level). The concordance of TLFB with either EMA or SCRAM was weak, especially at the day level. CONCLUSIONS: This is the first study to examine concordance of alcohol use estimates using EMA, SCRAM, and TLFB methods in adults experiencing homelessness. EMA is a valid approach to quantifying alcohol use, especially given its relatively low cost, low participant burden, and ease of use. Furthermore, any stigma associated with wearing the SCRAM or reporting alcohol use in person may be attenuated by using EMA, which may be appealing for use in studies of stigmatized and underserved populations.

Temperature induced changes in the optical properties of skin in vivo.

Knowledge of temperature-induced changes of skin optical properties is required for accurate dosimetry of photothermal treatments. We determined and compared in vivo optical properties of mouse ear skin at different temperatures. The diffuse reflectance, total and diffuse transmittance were measured in the spectral range from 400 to 1650 nm using an integrating sphere spectrometer at the temperatures of 25 °C, 36 °C and 60 °C. Target temperatures were attained and maintained using an automated heater equipped with a sensor for feed-back and control. Temperature and temperature induced morphological changes of skin were monitored using an infrared thermal camera and reflectance confocal microscopy, respectively. An inverse Monte Carlo technique was utilized to determine absorption, scattering, and anisotropy factors from the measured quantities. Our results indicate significant differences between the optical properties of skin at different temperatures. Absorption and scattering coefficients increased, whereas anisotropy factors decreased with increasing temperature. Changes in absorption coefficients indicate deoxygenation of hemoglobin, and a blue shift of water absorption bands. Confocal imaging confirmed that our observations can be explained by temperature induced protein denaturation and blood coagulation. Monitoring spectral responses of treated tissue may become a valuable tool for accurate dosimetry of light treatments.

Quantitative Assessment of Eosinophils in Dermatomyositis Skin Biopsies With Correlation of Eosinophils to Pruritus and Other Clinical Features.

ABSTRACT: The objective of this retrospective study was to analyze dermatomyositis skin biopsies for the presence of eosinophils and correlate this finding with other histopathologic and clinical characteristics. Cases of dermatomyositis evaluated in a single dermatologist's adult autoimmunity practice over a 2.5-year period were identified via ICD-10 diagnosis code. Dermatopathology archives were then searched for any corresponding biopsies consistent with dermatomyositis, and those identified were assessed for eosinophils, adnexal involvement, epidermal atrophy, dermal mucin, and basement membrane thickening. Histopathologic findings were correlated with key clinical features, including itch. A total of 39 biopsies from 17 patients were included. Eosinophils were noted in 44% of biopsies (n = 17) from 12 patients. Dermal mucin deposition and adnexal interface dermatitis were noted in 72% (n = 28) and 44% (n = 17) of biopsy specimens, respectively. Of 12 patients with eosinophils present in at least 1 biopsy specimen, 11 (92%) patients had a clinical history of pruritus of their skin lesions (P = 0.052). Limitations of this study include retrospective design and small number of patients.

Assessment of Transdermal Delivery of Topical Compounds in Skin Scarring Using a Novel Combined Approach of Raman Spectroscopy and High-Performance Liquid Chromatography.

Objective: The goal of any topical formulation is efficient transdermal delivery of its active components. However, delivery of compounds can be problematic with penetration through tough layers of fibrotic dermal scar tissue. Approach: We propose a new approach combining high-performance liquid chromatography (HPLC) and Raman spectroscopy (RS) using a topical of unknown composition against a well-known antiscar topical (as control). Results: Positive detection of compounds within the treatment topical using both techniques was validated with mass spectrometry. RS detected conformational structural changes; the 1,655/1,446 cm-1 ratio estimating collagen content significantly decreased (p < 0.05) over weeks 4, 12, and 16 compared with day 0. The amide I band, known to represent collagen and protein in skin, shifted from 1,667 to 1,656 cm-1, which may represent a change from ß-sheets in elastin to α-helices in collagen. Confirmatory elastin immunohistochemistry decreased compared with day 0, conversely the collagen I/III ratio increased in the same samples by week 12 (p < 0.05, and p < 0.0001, respectively), in keeping with normal scar formation. Optical coherence tomography attenuation coefficient representing collagen deposition was significantly decreased at week 4 compared with day 0 and increased at week 16 (p < 0.05). Innovation: This study provides a platform for further research on the simultaneous evaluation of the effects of compounds in cutaneous scarring by RS and HPLC, and identifies a role for RS in the therapeutic evaluation and theranostic management of skin scarring. Conclusions: RS can provide noninvasive information on the effects of topicals on scar pathogenesis and structural composition, validated by other analytical techniques.

Luliconazole loaded lyotropic liquid crystalline nanoparticles for topical delivery: QbD driven optimization, in-vitro characterization and dermatokinetic assessment.

Fungal infections are an important cause of morbidity and pose a serious health concern especially in immunocompromised patients. Luliconazole (LUL) is a topical imidazole antifungal drug with a broad spectrum of activity. To overcome the limitations of conventional dosage forms, LUL loaded lyotropic liquid crystalline nanoparticles (LCNP) were formulated and characterized using a three-factor, five-level Central Composite Design of Response Surface Methodology. LUL loaded LCNP showed particle size of 181 ± 12.3 nm with an entrapment efficiency of 91.49 ± 1.61 %. The LUL-LCNP dispersion in-vitro drug release showed extended release up to 54 h. Ex-vivo skin permeation studies revealed transdermal flux value (J) of LUL-LCNP gel (7.582 µg/h/cm2) 2 folds higher compared to marketed cream (3.3706 µg/h/cm2). The retention of LUL in the stratum corneum was ∼1.5 folds higher and ∼2 folds higher in the epidermis and other deeper layers in comparison to the marketed cream. The total amount of drug penetrated (AUC0-∞) with LCNP formulation was 4.7 folds higher in epidermis and 6.5 folds higher in dermis than marketed cream. The study's findings vouch that LCNP can be a promising and effective carrier system for the delivery of antifungal drugs with enhanced skin permeation.

Wearable Circuits Sintered at Room Temperature Directly on the Skin Surface for Health Monitoring.

A soft body area sensor network presents a promising direction in wearable devices to integrate on-body sensors for physiological signal monitoring and flexible printed circuit boards (FPCBs) for signal conditioning/readout and wireless transmission. However, its realization currently relies on various sophisticated fabrication approaches such as lithography or direct printing on a carrier substrate before attaching to the body. Here, we report a universal fabrication scheme to enable printing and room-temperature sintering of the metal nanoparticle on paper/fabric for FPCBs and directly on the human skin for on-body sensors with a novel sintering aid layer. Consisting of polyvinyl alcohol (PVA) paste and nanoadditives in the water, the sintering aid layer reduces the sintering temperature. Together with the significantly decreased surface roughness, it allows for the integration of a submicron-thick conductive pattern with enhanced electromechanical performance. Various on-body sensors integrated with an FPCB to detect health conditions illustrate a system-level example.

Handheld multispectral imager for quantitative skin assessment in low-resource settings.

SIGNIFICANCE: Spatial frequency domain imaging (SFDI) is a quantitative imaging method to measure absorption and scattering of tissue, from which several chromophore concentrations (e.g., oxy-/deoxy-/meth-hemoglobin, melanin, and carotenoids) can be calculated. Employing a method to extract additional spectral bands from RGB components (that we named cross-channels), we designed a handheld SFDI device to account for these pigments, using low-cost, consumer-grade components for its implementation and characterization. AIM: With only three broad spectral bands (red, green, blue, or RGB), consumer-grade devices are often too limited. We present a methodology to increase the number of spectral bands in SFDI devices that use RGB components without hardware modification. APPROACH: We developed a compact low-cost RGB spectral imager using a color CMOS camera and LED-based mini projector. The components' spectral properties were characterized and additional cross-channel bands were calculated. An alternative characterization procedure was also developed that makes use of low-cost equipment, and its results were compared. The device performance was evaluated by measurements on tissue-simulating optical phantoms and in-vivo tissue. The measurements were compared with another quantitative spectroscopy method: spatial frequency domain spectroscopy (SFDS). RESULTS: Out of six possible cross-channel bands, two were evaluated to be suitable for our application and were fully characterized (520 ± 20 nm; 556 ± 18 nm). The other four cross-channels presented a too low signal-to-noise ratio for this implementation. In estimating the optical properties of optical phantoms, the SFDI data have a strong linear correlation with the SFDS data (R2 = 0.987, RMSE = 0.006 for µa, R2 = 0.994, RMSE = 0.078 for µs'). CONCLUSIONS: We extracted two additional spectral bands from a commercial RGB system at no cost. There was good agreement between our device and the research-grade SFDS system. The alternative characterization procedure we have presented allowed us to measure the spectral features of the system with an accuracy comparable to standard laboratory equipment.

Chondroitin/dermatan sulfate purified from corb (Sciaena umbra) skin and bone: In vivo assessment of anticoagulant activity.

The present work deals with the extraction and purification of chondroitin sulfate/dermatan sulfate from skin (CSG) and bone (CBG) of corb (Sciaena umbra). Electrophoresis of these polymers in barium acetate buffer on cellulose acetate revealed two fractions similar to dermatan sulfate and chondroitin sulfate. The in vivo anticoagulant activity of both chondroitin sulfate/dermatan sulfate (CS/DS) were evaluated, at 25 and 75 mg kg-1 of body weight (b.w), using activated partial thromboplastin time (aPTT), prothrombine time (TT) and thrombin time (PT) tests. Results showed that aPTT of CSG and CBG at 75 mg kg-1 of b.w were prolonged by 1.59 and 1.48-fold respectively, compared with the control. Further, toxicity studies on liver performed by the catalytic activity of transaminases in plasma, oxidative stress markers and hepatic morphological changes demonstrated that CSG and CBG at both doses are not toxics. In summary, the higher activity and lower toxicity of both CS/DS, especially at 25 mg kg-1 of b.w, recommended these compounds as a better drug candidate.

Comprehensive assessment of Nile tilapia skin collagen sponges as hemostatic dressings.

Nile tilapia skin collagen sponge was fabricated by lyophilization and cross-linked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide in the presence of N-hydroxysuccinimide (EDC/NHS). The physicochemical properties were examined. The EDC/NHS cross-linked collagen sponge presented an enhanced water absorption capacity. In addition, biocompatibility and hemostatic efficiency were evaluated by acute systemic toxicity assay, dermal irritation test, intradermal reaction test, sensitization test, cytotoxicity, blood clotting assay in vitro, and liver and femoral artery hemorrhage models in vivo. Results showed that the produced collagen sponges before and after EDC/NHS cross-linking had excellent biocompatibility. Furthermore, EDC/NHS cross-linking promoted fibroblast cells viability and proliferation reflected by the MTT reduction assay. Meanwhile, EDC/NHS cross-linked collagen sponge exhibited the best blood clotting ability and hemostatic efficiency in rat femoral artery hemorrhage model in comparison with non-crosslinked and commercial collagen sponges. Our results demonstrated that the fabricated collagen sponges could be used as perfect hemostatic dressings.

Decellularized matrices for tumor cell modeling.

Collagen is the main component of the extracellular matrix and it plays a key role in tumor progression. Commercial collagen solutions are derived from animals, such as rat-tail and bovine or porcine skin. Their cost is quite high and the product is stable only at low temperature, with the disadvantage of a short expiring date. Most importantly, lot-to-lot variability can occur and the reconstituted collagen gels differ significantly from native tissues in terms of both structure and stiffness. In this chapter, we describe a straightforward method to use native, collagen rich skin samples derived from by-products of the tanning industry. The protocol proposed preserves the microstructure of the ovine skin collagen network, offering structurally competent and more relevant model to investigate cell behavior in vitro. Other advantages of the proposed procedure consist in the cost-effectiveness of the process and an increased level of reproducibility. The decellularized ovine skin samples support the adhesion and growth of different cancer cell lines (pancreatic, breast and melanoma cells). The proposed decellularized skin scaffolds are meant as future low-cost competitors for conventional porous scaffold derived by biomaterials, since they offer a biomimetic environment for the cells.

Comprehensive Assessment of Nile Tilapia Skin (Oreochromis niloticus) Collagen Hydrogels for Wound Dressings.

Collagen plays an important role in the formation of extracellular matrix (ECM) and development/migration of cells and tissues. Here we report the preparation of collagen and collagen hydrogel from the skin of tilapia and an evaluation of their potential as a wound dressing for the treatment of refractory wounds. The acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) were extracted and characterized using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), differential scanning calorimetry (DSC), circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) analysis. Both ASC and PSC belong to type I collagen and have a complete triple helix structure, but PSC shows lower molecular weight and thermal stability, and has the inherent low antigenicity. Therefore, PSC was selected to prepare biomedical hydrogels using its self-aggregating properties. Rheological characterization showed that the mechanical strength of the hydrogels increased as the PSC content increased. Scanning electron microscope (SEM) analysis indicated that hydrogels could form a regular network structure at a suitable PSC content. Cytotoxicity experiments confirmed that hydrogels with different PSC content showed no significant toxicity to fibroblasts. Skin repair experiments and pathological analysis showed that the collagen hydrogels wound dressing could significantly accelerate the healing of deep second-degree burn wounds and the generation of new skin appendages, which can be used for treatment of various refractory wounds.

Nephrogenic Systemic Fibrosis Risk Assessment and Skin Biopsy Quantification in Patients with Renal Disease following Gadobenate Contrast Administration.

BACKGROUND AND PURPOSE: Nephrogenic systemic fibrosis following administration of intravenous gadobenate during MR imaging is rare. This study aimed to analyze any nephrogenic systemic fibrosis-related risks and quantify skin gadolinium levels in patients with impaired renal function but without nephrogenic systemic fibrosis who had received gadobenate. MATERIALS AND METHODS: In this retrospective study with a prospective skin biopsy phase, patients with estimated glomerular filtration rates of <60 mL/min/1.73 m2 undergoing contrast-enhanced MR imaging from July 2007 through June 2014 were screened for nephrogenic systemic fibrosis using a questionnaire. This was highly sensitive but not specific and reliably excluded nephrogenic systemic fibrosis if responses to at least 6 of the 8 questions were negative. If no nephrogenic systemic fibrosis was detected, a skin biopsy was requested. RESULTS: Of 2914 patients who met these criteria, 1988 were excluded for various reasons. Of the remaining 926 patients, 860 were screened negative for nephrogenic systemic fibrosis. Of these, 17 (2%) had estimated glomerular filtration rates of <15 mL/min/1.73 m2, 51 (6%) had levels of 15 < 30 mL/min/1.73 m2, 234 (27%) had levels of 30 < 45 mL/min/1.73 m2, and 534 (62%) had levels of 45 < 60 mL/min/1.73 m2. Of the 66 who were not cleared of nephrogenic systemic fibrosis by the questionnaire, 6 patients were evaluated by a dermatologist and confirmed not to have nephrogenic systemic fibrosis (no biopsy required). CONCLUSIONS: A diagnosis of nephrogenic systemic fibrosis was excluded in 860 patients with impaired renal function who were followed up and received gadobenate during MR imaging. In 14 such patients who underwent at least 1 gadobenate-enhanced MR imaging examination and did not have nephrogenic systemic fibrosis, gadolinium levels in the skin were exceedingly low.