Pigmented Areas Research Articles

Comparing the effectiveness of hyperspectral imaging and Raman spectroscopy: a case study on Armenian manuscripts

There is great practical and scholarly interest in the identification of pigments in works of art. This paper compares the effectiveness of the widely used Raman Spectroscopy (RS), with hyperspectral imaging (HSI), a reflectance imaging technique, to evaluate the reliability of HSI for the identification of pigments in historic works of art and to ascertain if there are any benefits from using HSI or a combination of both. We undertook a case study based on six Armenian illuminated manuscripts (eleventh–eighteenth centuries CE) in the Bodleian Library, University of Oxford. RS, and HSI (380–1000 nm) were both used to analyse the same 10 folios, with the data then used to test the accuracy and efficiency of HSI against the known results from RS using reflectance spectra reference databases compiled by us for the project. HSI over the wavelength range 380–1000 nm agreed with RS at best 93% of the time, and performance was enhanced using the SFF algorithm and by using a database with many similarities to the articles under analysis. HSI is significantly quicker at scanning large areas, and can be used alongside RS to identify and map large areas of pigment more efficiently than RS alone. HSI therefore has potential for improving the speed of pigment identification across manuscript folios and artwork but must be used in conjunction with a technique such as RS.

MODERN VIEW ON THE EXPERIMENTAL AND CLINICAL JUSTIFICATION FOR THE USE OF PRF IN THE PROCESSES OF REPARATIVE SKIN REGENERATION

The article describes the use of fibrin glue, which is quite common in modern medical practice. It can be synthesized from the patient's venous blood or used as ready-made preparations.
 Among fibrin clots, depending on the method of their preparation, one can distinguish:
 
 PRF which is an ordinary fibrin clot and is prepared in vacuum tubes with a plasma activator and centrifuged for about 8-12 minutes at a rate of 3000-3500 revolutions per minute.
 A-PRF (advanced) - in this cluster, growth factors have a higher concentration and a more even distribution, which helps reduce the speed of the centrifuge to 2,000 revolutions per minute, while the centrifugation time is 8-12 minutes.
 i-PRF (injectable) is a fibrinous clot formed after a few minutes after receiving blood plasma by centrifugation. The speed is 1500-2000 rpm, the centrifugation time is 3 minutes.
 Stickybone is a blood plasma that turns into a clot due to the content of fibrin in the plasma itself. The preparation is similar to the usual PRF, but due to the absence of the coagulant activator in the vial, the rate of formation of the fibrin clot is much lower.
 
 The PRF contains an autologous fibrin matrix that is rich in leukocytes, platelets and cytokines, and has a tetramolecular structure that acts as a biodegradable framework. This matrix not only stimulates the development of the microvascular mesh, but also directs the migration of epithelial cells to the surface.
 The effect of PRF and fat cells on the repair of defects in soft tissue of the maxillofacial area was investigated in pigs. It has been found that combined use of PRF and fat cells contributes to more efficient reparative regeneration processes than their single use.
 The use of PRF is common in mucoadhesive surgery, mainly in donor areas, due to the possibility of leaving the fibrin membrane exposed, which stimulates the rapid healing of the wounds with a secondary tension. Also, PRF is used locally for gum recession. According to research by S.K. Agarwa PRF stimulates the increase in the width of the keratinous mucous membrane to 0.8-1.0 mm, reducing the gum recession, which in turn greatly enhances the aesthetics of the patient. The use of PRF is clinically grounded in the surgical treatment of pigmented gum area.
 There was a wide use of PRF in cases of surgical treatment of radicular jaw cysts, including odontogenic facial granulomas, to replace the defect of bone tissue. The use of PRF promotes accelerated bone regeneration within 3 months after surgery. Radiologically, after 6 months, there is a complete recovery of bone tissue and a probable increase in bone density. The use of the PRF membrane helps to prevent inflammatory complications during tooth extraction, such as after an alveolus extraction, and can be used to break down the wall of the alveoli, which accelerates the processes of reparative regeneration in this area and creates better prospects for further dental implantation.
 It is proved that the use of PRF causes the acceleration of the processes of reparative regeneration in various types of tissues, contributing to the improvement of treatment results.

Determining gut transit rates in gilthead seabream larvae fed microdiets

In this study we assessed an easy methodology for testing gut filling dynamics in early fish larvae fed on microdiets by means of image analysis. As model for this study we used gilthead seabream Sparus aurata, a species whose feeding physiology during the larval stage is well-known. Ingestion and food transit assays were carried out at different ages between 9 and 27 days after hatching (dph). Gut content was examined by image analysis in 10 larvae sampled respectively at 0, 20, 40, 60, and 120 min after the first morning meal. Gut fullness level was determined measuring the pigmented area within the digestive cavity. In each sampling point and larvae, relative percentage of shadowed area respect to the total area of intestinal cavity was considered as fullness percentage, assuming that intestinal area and volume are highly correlated. Data obtained were adjusted to an exponential model with maximum asymptotic: C = Cmax(1−e(−bt)), where C = % fullness; Cmax is the asymptote (theoretical percentage of maximum fullness), t = sampling time (min) and b is a regression parameter indicating the slope of the filling curve. Ingestion rate (I) was calculated as I = Cmax∗b. Ingestion rate was considered as Filling rate taken that the determined data are percentages instead of a number of prey items as usual. Filling rate was expressed as % of total gut volume per time unit. The food transit time (time required to fill completely the gut) was calculated as 100/I. Our results demonstrate that the methodology based in the image analysis of the shadowed area by food within the gut is a useful tool to build saturation curves as a function of time in small early larvae, using early seabream larvae as model. Our results also showed that although food intake increases with age the filling rate of digestive tract is practically constant in the range of age assessed. In summary, feeding rates and gut transit time can be estimated by image analysis in early fish larvae while the body still remains transparent. This methodology is particularly useful for advancing in the feeding behaviour of larvae fed on microdiets.

Identification of tumor margins using diffuse reflectance spectroscopy with an extended‐wavelength spectrum in a porcine model

A novel extended-wavelength diffuse reflectance spectroscopy (EWDRS) technique is being developed for future clinical non-invasive tumor margin delineation. In this study, the ability of EWDRS to identify the margins of pigmented skin lesions in an in vivo pig model was evaluated. Extended-wavelength diffuse reflectance spectroscopy recordings (350-1550nm) were made on 13 pigmented skin lesions and non-pigmented skin, as a reference. The hand-held probe was swept toward the pigmented area until the signal changed, thus indicating that the margin had been identified. A needle was inserted as a marker, and tissue samples were sent for histological analysis. The distance between the EWDRS-defined border and the histological border was measured by 3 independent examiners. The median difference between the EWDRS-defined border and the histological border was 70μm toward the pigmented tissue (range: -579 to 538μm). A Pearson correlation coefficient of .95 was obtained for the examiners. Extended-wavelength diffuse reflectance spectroscopy can be used in vivo to delineate the border of pigmented skin lesions in a porcine model with high accuracy, indicating that it may be a useful tool for non-invasive tumor margin delineation in the future.

Iris pigmented lesions as a marker of cutaneous melanoma risk: an Australian case-control study

Early diagnosis of melanoma of the skin leads to a higher chance of successful treatment and survival. Clinicians need to be aware of patients at high risk, such as those with multiple naevi (moles) to enable early detection of melanoma. Pigmented naevi and freckle‐like lesions (spots) are common in the iris, which is the coloured part of the eye around the pupil. It is known that pigmented iris lesions are associated with dysplastic skin naevi, meaning moles that are abnormal‐looking but not cancerous, but a link with melanoma has not been confirmed. The authors, mostly based in Brisbane, Australia, aimed to determine if iris pigmented lesions were a risk factor for melanoma. They examined and took digital eye photographs of 1117 dermatology patients who had been diagnosed with melanoma, and control subjects (without melanoma). They found that there was a 45% increased incidence of melanoma in patients under 40 who had three or more iris pigmented lesions; this was in addition to other risk factors for melanoma. They concluded that multiple areas of iris pigmentation were a risk factor for melanoma in people of European origin.

Dissociating the effect of disruptive colouration on localisation and identification of camouflaged targets

Disruptive camouflage features contrasting areas of pigmentation across the animals’ surface that form false edges which disguise the shape of the body and impede detection. In many taxa these false edges feature local contrast enhancement or edge enhancement, light areas have lighter edges and dark areas have darker edges. This additional quality is often overlooked in existing research. Here we ask whether disruptive camouflage can have benefits above and beyond concealing location. Using a novel paradigm, we dissociate the time courses of localisation and identification of a target in a single experiment. We measured the display times required for a stimulus to be located or identified (the critical duration). Targets featured either uniform, disruptive or edge enhanced disruptive colouration. Critical durations were longer for identifying targets with edge enhanced disruptive colouration camouflage even when presented against a contrasting background, such that all target types were located equally quickly. For the first time, we establish empirically that disruptive camouflage not only conceals location, but also disguises identity. This shows that this form of camouflage can be useful even when animals are not hidden. Our findings offer insights into how edge enhanced disruptive colouration undermines visual perception by disrupting object recognition.

Remediation of adult black dental stains by phototherapy

Introduction and aimsThis study investigates the effects of the application of antimicrobial phototherapy on black-stained tooth surfaces. Key variables were area, color and time taken to reappearance of black stain following dental prophylaxis with and without antimicrobial phototherapy. Differences in bacterial composition of black stain (specifically Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Porphyromonas gingivalis) were analyzed.Material and methodsThe phototherapy device used was GLO™ Science LLC, New York, America, emitting light at 475 nm and a power of 3 W. Light was applied in 2 cycles of 8 min on 31 volunteers. Microbial identification was carried out on DNA extracted from black plaque. This study is registered with ClinicalTrials.gov, number NCT03309748.ResultsFollowing antimicrobial phototherapy, 64.5% of patients displayed reduced pigmentation area. Plaque color was lighter in 48.4% of subjects. Pigmentation area and depth of color returned to normal levels during the course of the study. Colonization by the three bacterial species decreased, although the changes were not statistically significant. We report a key novel finding showing elevated levels of colonization by Tannerella forsythia (83.9%) in adult black stain.ConclusionsApplication of phototherapy results in a reduction in area, color and bacterial colonization of black plaque in adults. The changes were not found to be statistically significant, perhaps owing to the low illumination power of the home-whitening device. For the first time, we document the elevated presence of Tannerella forsythia in adult black stain. We also demonstrate the potential application of a commercially available home-whitening device for black plaque treatment.

Left-right pigmentation pattern of Japanese flounder corresponds to expression levels of melanocortin receptors (MC1R and MC5R), but not to agouti signaling protein 1 (ASIP1) expression

Body coloration in flatfish is one of the most distinctive asymmetries in the animal kingdom, although the fundamental molecular mechanism of the pigmentation is unclear. In the dorso-ventral coloration (countershading) of other teleost fishes, ventral-specific expression of agouti signaling protein 1 (ASIP1), an endogenous antagonist of melanocortin 1 receptor (MC1R), has been reported to play a pivotal role. Contribution of ASIP1 is also suggested in the asymmetrical pigmentation of flatfish. In order to confirm the contribution of ASIP1 and further examine receptor function in the body coloration of Japanese flounder, expression levels of asip1, mc1r, melanocortin 5 receptor (mc5r), and melanin-concentrating hormone receptor 2 (mchr2) were measured in the normally pigmented area of the left side, the normally non-pigmented area of the right side, and the abnormally pigmented (exhibiting hypermelanosis) area of the right side. Measurement was also carried out under conditions of hypermelanosis stimulated by cortisol and during the transition from non-pigmentation to pigmentation in areas of hypermelanosis. Contrary to our expectations, no difference was detected in asip1 expression between pigmented and non-pigmented areas. There was also no difference between normal and hormonally stimulated pigmented conditions in areas of hypermelanosis or during the transition process. Instead, the expression levels of mc1r, mc5r, and mchr2 were consistently higher in pigmented areas, and were especially increased under hormonally stimulated conditions. In addition, expressions of these receptor genes increased prior to pigmentation in areas of future hypermelanosis. Our results suggest that MC1Rand MC5R, but not necessarily ASIP1, contribute to pigmentation and hypermelanosis in Japanese flounder. We propose a yet unknown molecular mechanism for asymmetrical pigmentation in flatfish that is distinct from that of countershading in other vertebrates.

Assessment of skin condition by the modern non-invasive methods in the process of age-related changes correction using the erbium and neodymium lasers

The histological examination method is the «gold standard» in evaluating of age-related skin changes, however in most cases biopsy is an unacceptable option by ethical reasons. An alternative option are non-invasive diagnostic methods, in which the evaluation of changes can be carried out in real time without damaging the skin. Nowadays, such methods as high-frequency ultrasound, optical coherence tomography, laser scanning confocal microscopy, magnetic resonance imaging are used. In addition to the above-mentioned methods, it is necessary to hold a standardized clinical evaluation and determination of the physiological parameters of the skin. The evaluation of age-related skin changes of face zone and neck zone before and after the application of the combined erbium and neodymium laser exposure on the «Fotona» apparatus using the «Fotona 4D» technique has been held. There were 80 examined patients aged from 32 to 66 who, after a comprehensive clinical examination, conducted 2 procedures using the «Fotona 4D» method with an interval of 1 month. There was a significant decrease in the index of evaluation of age-related facial skin changes in the process of correction, which indicates a pronounced clinical effectiveness of the proposed technique (27 points at the screening stage and 12 points at 2 months after correction). There was also a normalization of skin moisture and an improvement in relief, reduction of pore diameter and pigmentation area. Analysis of high-frequency ultrasound data showed a statistically significant increase in skin thickness, mainly due to the dermis.

An endocrine-disrupting agricultural contaminant impacts sequential female mate choice in fish

The environmental impact of endocrine-disrupting chemicals (EDCs)—compounds that interfere with endocrine system function at minute concentrations—is now well established. In recent years, concern has been mounting over a group of endocrine disruptors known as hormonal growth promotants (HGPs), which are natural and synthetic chemicals used to promote growth in livestock by targeting the endocrine system. One of the most potent compounds to enter the environment as a result of HGP use is 17β-trenbolone, which has repeatedly been detected in aquatic habitats. Although recent research has revealed that 17β-trenbolone can interfere with mechanisms of sexual selection, its potential to impact sequential female mate choice remains unknown, as is true for all EDCs. To address this, we exposed female guppies (Poecilia reticulata) to 17β-trenbolone at an environmentally relevant level (average measured concentration: 2 ng/L) for 21 days using a flow-through system. We then compared the response of unexposed and exposed females to sequentially presented stimulus (i.e., unexposed) males that varied in their relative body area of orange pigmentation, as female guppies have a known preference for orange colouration in males. We found that, regardless of male orange pigmentation, both unexposed and exposed females associated with males indiscriminately during their first male encounter. However, during the second male presentation, unexposed females significantly reduced the amount of time they spent associating with low-orange males if they had previously encountered a high-orange male. Conversely, 17β-trenbolone-exposed females associated with males indiscriminately (i.e., regardless of orange colouration) during both their first and second male encounter, and, overall, associated with males significantly less than did unexposed females during both presentations. This is the first study to demonstrate altered sequential female mate choice resulting from exposure to an endocrine disruptor, highlighting the need for a greater understanding of how EDCs may impact complex mechanisms of sexual selection.

Coumestrol Confers Partial Resistance in Soybean Plants Against Cercospora Leaf Blight.

Although previous research showed that the purple symptom of Cercospora leaf blight (CLB) is associated with lower biomass of Cercospora cf. flagellaris and lower concentrations of cercosporin, a reactive oxygen species producer, as compared with blighted leaves, the hypothesis that the purple symptom is a plant reaction to the pathogen has never been tested. In this study, we demonstrated that high levels of coumestrol (COU) were associated with purple symptoms of CLB and that COU has strong antioxidant activity. Additionally, we found that COU is restricted to the pigmented areas of purple leaves, and the pigmentation is restricted to the adaxial surfaces, suggesting that COU may be acting as a sunscreen. Even though COU is associated with the purple leaf symptom, this coumestan is not the direct cause of discoloration in that COU is colorless. Quantification of chlorophyll a and b and total carotenoids suggested that blighted but not purple or asymptomatic leaves were undergoing photooxidative stress. Because the purple symptom is associated with high COU concentrations, lower biomass of C. cf. flagellaris, and lower cercosporin concentrations, we conclude that the purple symptom is a disease resistance reaction, mediated in part by COU, which provides a high level of antioxidant activity and, hence, partial resistance.

One-step crushing & cladding technology and enhanced anticorrosion activity of Zn3(PO4)2@AlH2P3O10 pigment

The high acidity and crushing difficulty of aluminum tripolyphosphate (AlH2P3O10, ATP) have been of great attention due to directly inhibiting its anticorrosive performance. Here, one-step crushing & cladding technology is designed to achieve the modification and crush of ATP concurrently. According to electrochemical impedance spectroscopy experiment, the impedance of Zn3(PO4)2@AlH2P3O10 (ZATP) pigment is 148.94% and 133.44% higher than those of ATP and Zn3(PO4)2 (ZP) pigment, respectively. The enhanced corrosion resistance of ZATP pigment is mostly ascribed to the coefficient of low acidity, spacing crush and surface modification. After the modification, the pH value of ATP pigment is increased from 2.84 to 6.58, thereby reducing the metal destruction caused by acidity. Moreover, the specific surface area (SBET) of ZATP pigment increased by 204.89% lies in the decreased particle size of the pigment significantly. Interestingly, ZP and ATP separately release active inhibitors in early and late corrosion process to form complicated chelate passive films isolating the steel panels from the aggressive electrolytes, exerting a synergistic anticorrosive effect. This technology provides an innovative thought for low-cost metal protection.

Observation of the presence of crypsis in white mulletMugil curema(Pisces: Mugilidae) juveniles under artificial rearing conditions

This study documents the presence of crypsis inMugil curemajuveniles under laboratory culture. Initially, the juveniles were located in one brown tank (BT1), later almost half of the individuals were placed in a white tank (WT) where they showed a pigmentation change to white. After being moved to another brown tank (BT2), the juveniles changed to their brown original colour, but kept a few small white spots on the dorsal axis of the body. The ventral head melanophore pattern also changed in the white specimens. Temperature (°C), oxygen (mg l−1) and Illuminance light (Lux m−2), total length (mm) and total weight (g) were determined by tank. Chromaticity was measured in L*(relative luminance) a*(measurement relating to the redness or greenness of the light) b*(measurement relating to the yellowness or blueness of the light) coordinates where all three values are required to completely describe an object’s colour. One-way ANOVA showed no differences for temperature, oxygen and illuminance light among tanks. Length and weight were similar for BT1 and WT but both were different from BT2. The white juveniles depicted similar L* as the WT background as well as the dorsal area of the brown pigmentation and converted juveniles to the brown tanks BT1 and BT2, respectively. Therefore, the fish's body relative luminance matches the background. To our knowledge this behaviour has not been reported before for any fish mullet either cultured or living in the wild.

A Painted Viking-Age Sculpture from York

This paper records and discusses a recent discovery of a Viking-age stone carving from York, the subsequent cleaning and conservation of which has revealed large areas of original lime plaster priming layer and pigment coating, including the first recorded use in Northumbrian sculpture of lead white.

Phenylketonuria: Our Experience in Nine Years at a Tertiary-level Referral Institute.

Introduction:Phenyl ketonuria is an inborn error of amino acid metabolism resulting in excessive phenyl alanine levels in blood resulting in a spectrum of neurological defects.Patients and Methods:We retrospectively went through the records of patients diagnosed as Phenyl ketonuria in the last nine years in our team and patients who's data could be accessed were analyzed in detail. Details of laboratory tests, imaging clinical features, course were recorded.Observation:A total of 32 patients were identified in nine years of which data was available only for 15 patients. Age at diagnosis varied from 2.5 years to 7 years. 73% were males. Global developmental delay, Microcephaly. Seizures blond hair, spasticity, regression, Ocular Hypertelorism, low set ears, Seborrhea, Hypotonia, Family history of mental retardation and Consanguinity was common one patient showed a large hypo pigmented area in left arm with eczematous rash.Results of Lab Tests:Urine ferric chloride test and DNPH was positive in all cases. Tandem mass spectroscopy showed elevated phenyl alanine, normal tyrosine and elevated PHE tyrosine ratio in all cases. MRI showed symmetrical Flair hyperintensities in T2 weighted images in the parieto occipital region hypo on T1 with no diffusion restriction in 11 cases and MRS was normal. Genetic testing showed one non consanguineous family having carrier state. Follow up is from 1 year to 5 years. Seizures controlled in all. Regular fallow up shows change in hair color and gain of mile stones. There was no mortality.Conclusion:Phenyl ketonuria is a controllable metabolic disease. However there is considerable delay before diagnosis resulting in persistence of sequelae in children with PKU as well as normal children born to PKU mothers which needs attention to prevent these complications.

CHARACTERISTICS OF PIGMENTED LESIONS IN TYPE 2 IDIOPATHIC MACULAR TELANGIECTASIA.

Pigment in the midretina is a characteristic sign in Type 2 idiopathic macular telangiectasia (MacTel) and is considered to characterize the late stage of the disease. Our aim was to investigate its incidence, and relationship with risk factors for MacTel, including outer retinal vascularization and subretinal neovascular proliferation (SRNV). Pigment extent was measured in fundus autofluorescence images of 150 eyes of 75 MacTel probands, using the Region Finder tool of Heidelberg Eye Explorer. A linear mixed model was used to analyze the dynamics of pigment and its associations with other features of the phenotype. The relative incidence of pigment and of outer retinal outer retinal vascularization and SRNV was analyzed within the full MacTel Study cohort (1,244 probands). Mean pigment area at baseline was 0.157 mm (range = 0-1.295 mm, SD = 0.228 mm, n = 101). Progression demonstrated a nonlinear pattern (P < 0.001) at an overall rate of 0.0177 mm/year and was associated with the initial plaque size and with SRNV. There was a strong correlation between fellow eyes (P ≤ 0.0001). In approximately 25% of all SRNV cases, SRNV may coincide with or precede pigment. Our data may be useful for refining the current system for staging disease severity in MacTel.

Oral drug-induced lichenoid reaction in pediatric age group

Mucocutaneous diseases in the pediatric population are extremely rare and, hence, can have both psychological and behavioral bearing. Mucosal conditions in children include herpetic stomatitis, vesiculobullous lesions, aphthous and traumatic ulcerations, candidiasis, lichen planus, and drug-related mucosal lesions. This case report deals with a rare presentation of a 4-year-old child reporting with an extensive involvement of oral cavity with erythematous, ulcerative, and pigmented areas associated with drug intake.

Design and Experiment of a Sorting System for Haploid Maize Kernel

This study designed an automatic sorting system that can separate haploid maize kernels from cross-breeding kernels that are marked with the Navajo label. This system comprises the seed feeding, image acquisition, sorting and system control units. The seed feeding unit distributes the maize kernels over the synchronous belt. The image acquisition unit acquires the images of maize kernels, as well as distinguishes the heterozygous from haploid kernels based on the color feature of the endosperm. The sorting unit contains mechanical arms and solenoid valves that can select the heterozygote kernels using air suction. Lastly, the system control unit is compatible with other units. Four maize varieties, namely, 958-CAU, 1050-37, LC0990-LN75 and LC0995-CAU, were provided by China Agricultural University, National Maize Improvement Center. These varieties were selected for the experiments conducted. The successful unloading rates of the system are 85.56%, 91.39%, 87.22% and 86.39%, respectively. (R[Formula: see text]G)[Formula: see text]G–B[Formula: see text]/B was employed to distinguish the pigmented endosperm area. The accuracy rates of identification for the heterozygous kernels are 92.91%, 95.04%, 88.82% and 92.65% for 958-CAU, 1050-37, LC0990-LN75 and LC0995-CAU, respectively.

Developmental toxicity and inhibition of the fungicide hymexazol to melanin biosynthesis in zebrafish embryos

Hymexazol is an efficacious and widely used fungicide. However, its environmental toxicological assessment has not been well documented. It had no report of its toxicity to fish embryo. Fish embryo acute toxicity tests are highly predictive of aquatic embryotoxicity outcome. In this study, zebrafish (Danio rerio) embryos were exposed to hymexazol at varying concentrations for the study of the developmental toxicity, melanin biosynthesis, biochemical and transcriptional endpoints. The embryotoxicity tests indicated that the 96h LC50 value of hymexazol was 649mg/L with a 95% confidence interval range of 632–667mg/L. Hymexazol at concentrations of 417–738mg/L decreased the heart rate and increased the voluntary swing. Hymexazol inhibited normal development at concentrations above 554mg/L. the 96h EC50 was 411mg/L. Hymexazol in a concentration range of 417–738mg/L induced cardiac edema and yolk sac edema. Exposure of hymexazol at such concentrations to zebrafish embryos for 48h decreased the pigment area density compared with the no hymexazol control. Tyrosinase activity was inhibited by hymexazol relative to the untreated control. The P53 mRNA expression level in embryos upon exposure to 480mg/L or greater of hymexazol was significantly higher than that of the control. The results indicated that hymexazol has quite low acute toxicity and low embryotoxicity to zebrafish

A case of generalized argyria presenting with muscle weakness

BackgroundArgyria is a rare irreversible cutaneous pigmentation disorder caused by prolonged exposure to silver. Herein, we report a case of generalized argyria that developed after chronic ingestion of soluble silver-nano particles and presented with muscle weakness.Case presentationA 74-year-old woman visited our emergency room, complaining of fever and mental deterioration. She was diagnosed with acute pyelonephritis and recovered after antibiotic therapy. At presentation, diffuse slate gray-bluish pigmented patches were noticed on her face and nails. Two months prior to visiting our hospital, she was diagnosed with inflammatory myopathy and given steroid therapy at another hospital. We performed a nerve conduction study that revealed polyneuropathy. In skin biopsies from pigmented areas of the forehead and nose, the histopathologic results showed brown-black granules in basement membranes of sweat gland epithelia, which are diagnostic findings of argyria. We reviewed pathology slides obtained from the left thigh muscles and found markedly degenerated myofibers with disorganization of myofibrils without inflammatory reactions, consistent with unspecified myopathy, rather than inflammatory myopathy. The patient was diagnosed with generalized argyria with polyneuropathy and myopathy and transferred to a rehabilitation institution after being tapered off of steroids.ConclusionsClinicians should be aware of clinical manifestations of argyria and consider it in differential diagnosis when they examine patients who present with skin pigmentation and muscle weakness.