Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.511
Filtrar
1.
PLoS One ; 15(8): e0237023, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785244

RESUMO

OBJECTIVE: Melanocytes play a central role in skin homeostasis. In this study, we focus on the function of melanocyte releasing exosomes as well as exosomal microRNAs (miRNAs) and investigate whether ultraviolet B (UVB) irradiation exerts an impact on it. MATERIALS AND METHODS: Exosomes derived from human primary melanocytes were isolated through differential centrifugation and were identified in three ways, including transmission electron microscopy observation, nanoparticle tracking analysis, and Western blot analysis. Melanocytes were irradiated with UVB for the indicated time, and then melanin production and exosome secretion were measured. The exosomal miRNA expression profile of melanocytes were obtained by miRNA sequencing and confirmed by real-time PCR. RESULTS: Exosomes derived from human primary melanocytes were verified. UVB irradiation induced melanin production and increased the exosome release by the melanocytes. In total, 15 miRNAs showed higher levels in UVB-irradiated melanocyte-derived exosomes compared with non-irradiated ones, and the top three upregulated exosomal miRNAs were miR-4488, miR-320d, and miR-7704 (fold change > 4.0). CONCLUSION: It is verified for the first time that UVB irradiation enhanced the secretion of exosomes by melanocytes and changed their exosomal miRNA profile. This findings open a new direction for investigating the communication between melanocytes and other skin cells, and the connection between UVB and skin malignant initiation.


Assuntos
Exossomos/genética , Melanócitos/metabolismo , Melanócitos/efeitos da radiação , Secreções Corporais/metabolismo , Exossomos/metabolismo , Humanos , Melaninas/análise , MicroRNAs/genética , Cultura Primária de Células , Transcriptoma/genética , Raios Ultravioleta/efeitos adversos
2.
BMC Neurol ; 20(1): 262, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32605601

RESUMO

BACKGROUND: In this study, we explored whether the proposed short-echo-time magnitude (setMag) image derived from quantitative susceptibility mapping (QSM) could resemble NM-MRI image in substantia nigra (SN), by quantitatively comparing the spatial similarity and diagnosis performances for Parkinson's disease (PD). METHODS: QSM and NM-MRI were performed in 18 PD patients and 15 healthy controls (HCs). The setMag images were calculated using the short-echo-time magnitude images. Bilateral hyperintensity areas of SN (SNhyper) were manually segmented on setMag and NM-MRI images by two raters in a blinded manner. The inter-rater reliability was evaluated by the intraclass correlation coefficients (ICC) and the Dice similarity coefficient (DSC). Then the inter-modality (i.e. setMag and NM-MRI) spatial similarity was quantitatively assessed using DSC and volume of the consensual voxels identified by both of two raters. The performances of mean SNhyper volume for PD diagnosis on setMag and NM-MRI images were evaluated using receiver operating characteristic (ROC) analysis. RESULTS: The SNhyper segmented by two raters showed substantial to excellent inter-rater reliability for both setMag and NM-MRI images. The DSCs of SNhyper between setMag and NM-MRI images showed substantial to excellent voxel-wise overlap in HCs (0.80 ~ 0.83) and PD (0.73 ~ 0.76), and no significant difference was found between the SNhyper volumes of setMag and NM-MRI images in either HCs or PD (p > 0.05). The mean SNhyper volume was significantly decreased in PD patients in comparison with HCs on both setMag images (77.61 mm3 vs 95.99 mm3, p < 0.0001) and NM-MRI images (79.06 mm3 vs 96.00 mm3, p < 0.0001). Areas under the curve (AUCs) of mean SNhyper volume for PD diagnosis were 0.904 on setMag and 0.906 on NM-MRI images. No significant difference was found between the two curves (p = 0.96). CONCLUSIONS: SNhyper on setMag derived from QSM demonstrated substantial spatial overlap with that on NM-MRI and provided comparable PD diagnostic performance, providing a new QSM-based multi-contrast imaging strategy for future PD studies.


Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Melaninas/análise , Doença de Parkinson/diagnóstico por imagem , Substância Negra/diagnóstico por imagem , Idoso , Feminino , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Curva ROC , Reprodutibilidade dos Testes
3.
Int J Mol Sci ; 21(1)2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31906476

RESUMO

Bioactive collagen/chitosan complexes were prepared by an ion crosslinking method using fish skin collagen and chitosan solution as raw materials. Scanning electron microscopy observation confirmed that the collagen/chitosan complexes were of a uniform spherical shape and uniform particle size. The complexes were stable at different pH values for a certain period of time through swelling experiments. Differential scanning calorimetry (DSC) showed the collagen/ chitosan complexes were more stable than collagen. X-ray diffraction (XRD) showed that the complexes had a strong crystal structure, and Fourier transform infrared spectroscopy (FTIR) data revealed the changes in the secondary structure of the protein due to chitosan and TPP crosslinking. The content of malondialdehyde (MDA) in the complex treatment group was considerably lower, but the content of SOD was significantly higher than that of the collagen group or chitosan group. In addition, the collagen/chitosan complexes could considerably reduce melanin content, inhibit tyrosinase activity, and down-regulate tyrosinase mRNA expression. In conclusion, the collagen/chitosan complexes were potential oral protein preparation for antioxidant enhancement and inhibiting melanin synthesis.


Assuntos
Antioxidantes/farmacologia , Quitosana/química , Colágeno/química , Colágeno/farmacologia , Melaninas/biossíntese , Monofenol Mono-Oxigenase/antagonistas & inibidores , Animais , Varredura Diferencial de Calorimetria , Quitosana/farmacologia , Colágeno/ultraestrutura , Feminino , Concentração de Íons de Hidrogênio , Masculino , Malondialdeído/análise , Malondialdeído/metabolismo , Melaninas/análise , Melaninas/metabolismo , Melanoma Experimental , Camundongos , Microscopia Eletrônica de Varredura , Monofenol Mono-Oxigenase/genética , Monofenol Mono-Oxigenase/metabolismo , Tamanho da Partícula , Conformação Proteica , Espectroscopia de Infravermelho com Transformada de Fourier , Superóxido Dismutase/análise , Superóxido Dismutase/metabolismo , Difração de Raios X
4.
J Invest Dermatol ; 140(2): 257-268.e8, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31980058

RESUMO

Pigmentation of the skin and hair represents the result of melanin biosynthesis within melanosomes of epidermal melanocytes, followed by the transfer of mature melanin granules to adjacent keratinocytes within the basal layer of the epidermis. Natural variation in these processes produces the diversity of skin and hair color among human populations, and defects in these processes lead to diseases such as oculocutaneous albinism. While genetic regulators of pigmentation have been well studied in human and animal models, we are still learning much about the cell biological features that regulate melanogenesis, melanosome maturation, and melanosome motility in melanocytes, and have barely scratched the surface in our understanding of melanin transfer from melanocytes to keratinocytes. Herein, we describe cultured cell model systems and common assays that have been used by investigators to dissect these features and that will hopefully lead to additional advances in the future.


Assuntos
Técnicas de Cultura de Células , Melaninas/análise , Melanossomas/química , Transtornos da Pigmentação/patologia , Pigmentação da Pele/fisiologia , Animais , Técnicas de Cocultura , Humanos , Processamento de Imagem Assistida por Computador , Microscopia Intravital/métodos , Queratinócitos/metabolismo , Melaninas/metabolismo , Melanossomas/metabolismo , Melanossomas/ultraestrutura , Microscopia Eletrônica de Transmissão/métodos , Microscopia de Fluorescência/métodos , Projetos de Pesquisa , Espectrofotometria/métodos
5.
Int J Colorectal Dis ; 35(2): 213-222, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31823053

RESUMO

BACKGROUND: Melanosis coli (MC) is a colonoscopic finding in which the colonic mucosa appears darkly pigmented than usual and generally caused by extended anthranoid laxative use. METHODS: We performed a retrospective study at Zhuhai Hospital to investigate the risk of MC for CR neoplasm development. A total of 12,776 patients who underwent colonoscopy from 2013 to 2016 including 250 diagnosed with MC and 500 controls were included in this study. Odds ratios (OR) and 95% confidence intervals (95%CI) for associations of MC with CR neoplasm detection were estimated using univariate and multivariable multinomial logistic analyses for known risk factors. RESULTS: The presence of MC was associated with a significant increase in the CR neoplasm detection rate compared with controls (OR = 1.701, 95% CI = 1.252-2.31; P = 0.001). The effect was also observed in different tumor sites, age group, gender, and lifestyle. Using univariate multinomial analysis, patients with MC were significantly associated with both hyperplastic polyp (OR = 2.069, 95% CI = 1.253-3.415; P = 0.005) and low-grade (LG) adenoma (OR = 1.585, 95% CI = 1.115-2.254; P = 0.010). However, there was no significant difference with adenocarcinoma (OR = 1.701, 95% CI = 0.990-2.924; P = 0.055). Using multivariate multinomial analysis, MC patients remained associated with increased hyperplastic polyp (OR = 1.870, 95% CI = 1.119-3.125; P = 0.017) and LG adenoma (OR = 1.474, 95% CI = 1.027-2.114; P = 0.035), but not adenocarcinoma (OR = 1.620, 95% CI = 0.914-2.871; P = 0.098). A significant increase in CR neoplasm rate was observed with drinker, smoker, and elderly patients but not with gender. CONCLUSION: Patients with MC were more likely to have both hyperplastic polyp and LG adenoma. If confirmed, such findings could suggest the discontinuation of anthranoid laxative use particularly in the elderly.


Assuntos
Pólipos Adenomatosos/epidemiologia , Colo/patologia , Doenças do Colo/epidemiologia , Pólipos do Colo/epidemiologia , Colonoscopia , Neoplasias Colorretais/epidemiologia , Mucosa Intestinal/patologia , Melanose/epidemiologia , Pólipos Adenomatosos/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , China/epidemiologia , Colo/química , Doenças do Colo/patologia , Pólipos do Colo/patologia , Neoplasias Colorretais/patologia , Feminino , Humanos , Mucosa Intestinal/química , Masculino , Melaninas/análise , Melanose/patologia , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prevalência , Prognóstico , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Adulto Jovem
6.
Drug Test Anal ; 12(2): 230-238, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31655024

RESUMO

Hair analysis has become a valuable tool in forensic toxicology to assess drug or alcohol abstinence. Yet, hair adulteration by cosmetic products presents a major challenge for forensic hair analysis. Oxidative treatments, e.g. bleaching, may lead to analyte loss and thereby to false negative results. Currently, the eumelanin degradation product 1H-pyrrole-2,3,5-tricarboxylic acid (PTCA) serves as a marker for oxidative hair treatment, but requires the definition of cut-off values. To investigate further eumelanin degradation products as markers for oxidative hair treatment, hair samples with and without in vitro bleaching (hydrogen peroxide (H2 O2 ) concentrations 1.9% up to 12%; incubation times 15 min, 30 min, 60 min) were analyzed by liquid chromatography coupled to high-resolution time of flight mass spectrometry (HPLC-HRMS). The distribution of eumelanin degradation products along the hair shaft was investigated for routine applicability after segmentation of cosmetically untreated hair samples and authentically treated hair samples. The signals of the eumelanin degradation products PTCA, 1H-pyrrole-2,3,4-tricarboxylic acid (isoPTCA), and 1H-pyrrole-2,3,4,5-tetracarboxylic acid (PTeCA) were found to be significantly elevated after in vitro bleaching already with low H2 O2 concentrations and after short incubation times. In contrast to PTCA and isoPTCA, PTeCA was not detectable in cosmetically untreated segments up to 12 cm from hair root and was only formed through the oxidation process. The results of the study show that the detection of PTeCA within the proximal 3 to 6 cm segment can be applied to reliably detect hair adulteration attempts through hair bleaching.


Assuntos
Ácidos Carboxílicos/análise , Cabelo/química , Peróxido de Hidrogênio/química , Pirróis/análise , Cromatografia Líquida de Alta Pressão , Contaminação de Medicamentos , Toxicologia Forense , Humanos , Melaninas/análise , Oxirredução
7.
J Biomed Opt ; 24(12): 1-11, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31820596

RESUMO

When analyzing multidiameter single-fiber reflectance (MDSFR) spectra, the inhomogeneous distribution of melanin pigments in skin tissue is usually not accounted for. Especially in heavily pigmented skins, this can result in bad fits and biased estimation of tissue optical properties. A model is introduced to account for the inhomogeneous distribution of melanin pigments in skin tissue. In vivo visible MDSFR measurements were performed on heavily pigmented skin of type IV to VI. Skin tissue optical properties and related physiological properties were extracted from the measured spectra using the introduced model. The absorption of melanin pigments described by the introduced model demonstrates a good correlation with the co-localized measurement of the well-known melanin index.


Assuntos
Melaninas/análise , Pele , Análise Espectral/métodos , Algoritmos , Humanos , Imagens de Fantasmas , Pele/química , Pele/diagnóstico por imagem
8.
Dermatol Online J ; 25(9)2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31738846

RESUMO

A 28-year-old man with a history of mycosis fungoides presented for evaluation of multiple dark-brown macules and hyperpigmented dome-shaped papules on the distal tongue. A shave biopsy of the tongue revealed melanin pigment in the basal keratinocytes and melanophages in the lamina propria, consistent with pigmented fungiform papillae of the tongue. Relevant clinical and histologic features of this diagnosis are reviewed.


Assuntos
Hiperpigmentação/patologia , Melaninas , Papilas Gustativas/patologia , Doenças da Língua/patologia , Adulto , Humanos , Hiperpigmentação/etiologia , Masculino , Melaninas/análise , Micose Fungoide/complicações , Neoplasias Cutâneas/complicações , Doenças da Língua/etiologia
9.
Fish Shellfish Immunol ; 95: 514-518, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31682998

RESUMO

In order to understand the pathophysiology of melanomcrophage centers (MMCs) formation during the tilapia defense response to bacterial infections, the present study evaluated the response, in terms of area, number and pigment constitution, of splenic MMCs of Oreochromis niloticus subjected to intraperitoneal (i.p.) infection with Aeromonas hydrophila and Mycobacterium marinum. Eighty-four fish (396.9 ±â€¯21.0 g) were randomly distributed into twelve plastic tanks (300 L), to constitute three treatments with 28 animals each: control group (inoculated with PBS); Infected with A. hydrophila (1 × 107 UFC mL-1); Infected with M. marinum (1 × 106 UFC mL-1). The spleen was collected in seven fish per treatment on the 3rd, 7th, 14th and 21st day post-infection (DPI). The results revealed the participation of MMCs in the defense response of tilapia during bacterial infection by A. hydrophila and M. marinum, since there was an increase in the number and size of these cell aggregates. Variation of pigment accumulation with significant increase of hemosiderin, in infected tilapias by A. hydrophila, bacteria responsible for causing hemolytic anemia in fish was also found. On the other hand, M. marinum-infected tilapia had high amount of melanin in MMCs. In general, mycobacterial infections are notoriously difficult to treat, being characterized as a chronic disease. These findings demonstrate different strategies of fish response during the evolution of these bacterial diseases.


Assuntos
Ciclídeos/imunologia , Doenças dos Peixes/imunologia , Infecções por Bactérias Gram-Negativas/imunologia , Macrófagos/imunologia , Infecções por Mycobacterium não Tuberculosas/veterinária , Baço/imunologia , Aeromonas hydrophila/imunologia , Animais , Ciclídeos/microbiologia , Feminino , Doenças dos Peixes/microbiologia , Hemossiderina/análise , Masculino , Melaninas/análise , Infecções por Mycobacterium não Tuberculosas/imunologia
10.
J Food Biochem ; 43(12): e13077, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31608463

RESUMO

The water-soluble melanins (SM) of Randia echinocarpa fruit possess interesting biological activities and have been scarcely characterized. In this study, SM were obtained at boiling (SMBT) and room (SMRT) temperatures and characterized by UV-Vis, IR, thermogravimetric analysis, and GC-MS of the hydrolysis products of the SM; besides, the solid-state 13 C NMR, elemental analysis, and acute and sub-acute toxicity of the SMBT were determined. SMBT and SMRT contain organic acids and carbohydrates and their spectroscopic signals and thermograms were similar, but the SMBT yield was higher. The SMBT were characterized by their elemental composition (C 48.260 ± 0.011%, N 3.693 ± 0.009% and H 6.093 ± 0.076%) consistent with the presence of aromatic rings and eumelanins, degradation temperature at 300°C, 13 C NMR signals supporting melanin-bonding with carbohydrates and organic acids, and innocuity in Balb/C mice (acute assay, LD50  > 5 g/kg b.w.; sub-acute assay, no lethality at 500 mg/kg b.w. for 30 days). PRACTICAL APPLICATIONS: The consumption of melanins has been associated with health benefits because of their biological activities (e.g., antioxidant, immunostimulatory, UV- and radiation-protective). Randia echinocarpa is employed in Mexican traditional medicine against chronic degenerative diseases (e.g., cancer and diabetes) and ailments of organs (e.g., kidney and lung) and systems (e.g., circulatory and gastrointestinal). The R. echinocarpa fruit contains water-soluble melanins (SM) that inhibit carbohydrate-digestive enzymes and show high antioxidant activity; thus, SM could be useful for the prevention and treatment of diabetes. This study showed that the SM structure contains melanin-bonding organic acids and carbohydrates, which could be associated with the SM solubility and higher yield, and that SMBT were innocuous in the acute and sub-acute assays in mice. Thus, the R. echinocarpa SMBT could be used as safe potential ingredients to develop functional products.


Assuntos
Frutas/química , Melaninas/análise , Extratos Vegetais/análise , Animais , Camundongos , Camundongos Endogâmicos BALB C , Rubiaceae , Solubilidade , Testes de Toxicidade
11.
Nature ; 573(7772): 122-125, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31413368

RESUMO

Fossilized eyes permit inferences of the visual capacity of extinct arthropods1-3. However, structural and/or chemical modifications as a result of taphonomic and diagenetic processes can alter the original features, thereby necessitating comparisons with modern species. Here we report the detailed molecular composition and microanatomy of the eyes of 54-million-year-old crane-flies, which together provide a proxy for the interpretation of optical systems in some other ancient arthropods. These well-preserved visual organs comprise calcified corneal lenses that are separated by intervening spaces containing eumelanin pigment. We also show that eumelanin is present in the facet walls of living crane-flies, in which it forms the outermost ommatidial pigment shield in compound eyes incorporating a chitinous cornea. To our knowledge, this is the first record of melanic screening pigments in arthropods, and reveals a fossilization mode in insect eyes that involves a decay-resistant biochrome coupled with early diagenetic mineralization of the ommatidial lenses. The demonstrable secondary calcification of lens cuticle that was initially chitinous has implications for the proposed calcitic corneas of trilobites, which we posit are artefacts of preservation rather than a product of in vivo biomineralization4-7. Although trilobite eyes might have been partly mineralized for mechanical strength, a (more likely) organic composition would have enhanced function via gradient-index optics and increased control of lens shape.


Assuntos
Artrópodes/anatomia & histologia , Artrópodes/química , Dípteros/anatomia & histologia , Dípteros/química , Fósseis , Pigmentos Biológicos/análise , Pigmentos Biológicos/química , Animais , Biomarcadores/análise , Biomarcadores/química , Feminino , Tentilhões , Masculino , Melaninas/análise , Melaninas/química , Óptica e Fotônica
12.
Int J Mol Sci ; 20(16)2019 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-31412656

RESUMO

The generic term "melanin" describes a black pigment of biological origin, although some melanins can be brown or even yellow. The pigment is characterized as a heterogenic polymer of phenolic or indolic nature, and the classification of eu-, pheo- and allo- melanin is broadly accepted. This classification is based on the chemical composition of the monomer subunit structure of the pigment. Due to the high heterogeneity of melanins, their analytical characterization can be a challenging task. In the present work, we synthesized the current information about the analytical methods which can be applied in melanin analysis workflow, from extraction and purification to high-throughput methods, such as matrix-assisted laser desorption/ionization mass-spectrometry or pyrolysis gas chromatography. Our thorough comparative evaluation of analytical data published so far on melanin analysis has proven to be a difficult task in terms of finding equivalent results, even when the same matrix was used. Moreover, we emphasize the importance of prior knowledge of melanin types and properties in order to select a valid experimental design using analytical methods that are able to deliver reliable results and draw consistent conclusions.


Assuntos
Melaninas/análise , Melaninas/isolamento & purificação , Animais , Fracionamento Químico , Fenômenos Químicos , Humanos , Estrutura Molecular , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Análise Espectral
14.
J Comp Neurol ; 527(18): 2973-3001, 2019 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-31152440

RESUMO

Melanin-concentrating hormone (MCH) is a conserved neuropeptide, predominantly located in the diencephalon of vertebrates, and associated with a wide range of functions. While functional studies have focused on the use of the traditional mouse laboratory model, critical gaps exist in our understanding of the morphology of the MCH system in this species. Even less is known about the nontraditional animal model Neotomodon alstoni (Mexican volcano mouse). A comparative morphological study among these rodents may, therefore, contribute to a better understanding of the evolution of the MCH peptidergic system. To this end, we employed diverse immunohistochemical protocols to identify key aspects of the MCH system, including its spatial relationship to another neurochemical population of the tuberal hypothalamus, the orexins. Three-dimensional (3D) reconstructions were also employed to convey a better sense of spatial distribution to these neurons. Our results show that the distribution of MCH neurons in all rodents studied follows a basic plan, but individual characteristics are found for each species, such as the preeminence of a periventricular group only in the rat, the lack of posterior groups in the mouse, and the extensive presence of MCH neurons in the anterior hypothalamic area of Neotomodon. Taken together, these data suggest a strong anatomical substrate for previously described functions of the MCH system, and that particular neurochemical and morphological features may have been determinant to species-specific phenotypes in rodent evolution.


Assuntos
Hormônios Hipotalâmicos/metabolismo , Hipotálamo/citologia , Hipotálamo/metabolismo , Melaninas/metabolismo , Melanóforos/metabolismo , Hormônios Hipofisários/metabolismo , Animais , Feminino , Hormônios Hipotalâmicos/análise , Hipotálamo/química , Masculino , Melaninas/análise , Camundongos , Camundongos Endogâmicos C57BL , Filogenia , Hormônios Hipofisários/análise , Ratos , Ratos Sprague-Dawley , Especificidade da Espécie
15.
Pigment Cell Melanoma Res ; 32(6): 809-816, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31233275

RESUMO

Melanin in the skin can be divided into eumelanin and pheomelanin subtypes. Simultaneous quantification of these subtypes could clarify their relation to skin type and skin cancer development. We describe a novel, sensitive liquid chromatography-tandem mass spectrometry method to quantify two eumelanin markers, pyrrole-2,3,5-tricarboxylic acid (PTCA) and pyrrole-2,3-dicarboxylic acid (PDCA), and two pheomelanin markers, thiazole-4,5-dicarboxylic acid (TDCA) and thiazole-2,4,5 tricarboxylic acid (TTCA), performed in a single run using the same biopsy. Volunteers with either Fitzpatrick skin type (FST) I/II or III/IV (n = 30) each provided a 4-mm punch biopsy from the buttock. Upon analysis, the FST I + II group had significantly less of all four melanin biomarkers (PTCA, 0.75 ng/mm2 ; PDCA, 0.08 ng/mm2 ; TTCA, 0.24 ng/mm2 ; and TDCA, 0.10 ng/mm2 ) versus the FST III + IV group (PTCA, 4.89 ng/mm2 ; PDCA, 0.22 ng/mm2 ; TTCA, 2.61 ng/mm2 ; and TDCA, 0.72 ng/mm2 ), p ≤ 0.003. We find that this new LC-MS/MS method is sensitive enough to quantify eumelanin and pheomelanin markers even in the lightest skin types.


Assuntos
Melaninas/análise , Pele/metabolismo , Pele/efeitos da radiação , Espectrometria de Massas em Tandem/métodos , Raios Ultravioleta , Biomarcadores/análise , Biópsia , Cromatografia Líquida , Humanos , Limite de Detecção , Padrões de Referência , Pele/patologia
16.
Nat Commun ; 10(1): 2250, 2019 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-31113945

RESUMO

Recent progress has been made in paleontology with respect to resolving pigmentation in fossil material. Morphological identification of fossilized melanosomes has been one approach, while a second methodology using chemical imaging and spectroscopy has also provided critical information particularly concerning eumelanin (black pigment) residue. In this work we develop the chemical imaging methodology to show that organosulfur-Zn complexes are indicators of pheomelanin (red pigment) in extant and fossil soft tissue and that the mapping of these residual biochemical compounds can be used to restore melanin pigment distribution in a 3 million year old extinct mammal species (Apodemus atavus). Synchotron Rapid Scanning X-ray Fluorescence imaging showed that the distributions of Zn and organic S are correlated within this fossil fur just as in pheomelanin-rich modern integument. Furthermore, Zn coordination chemistry within this fossil fur is closely comparable to that determined from pheomelanin-rich fur and hair standards. The non-destructive methods presented here provide a protocol for detecting residual pheomelanin in precious specimens.


Assuntos
Extinção Biológica , Fósseis , Melaninas/análise , Animais , Cabelo/química , Melaninas/química , Murinae , Imagem Óptica/instrumentação , Imagem Óptica/métodos , Paleontologia/métodos , Análise Espectral/instrumentação , Análise Espectral/métodos , Enxofre/química , Zinco/química
17.
Eur J Neurol ; 26(11): 1408-1416, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31136060

RESUMO

BACKGROUND AND PURPOSE: Whether the neuromelanin-positive substantia nigra pars compacta area (NM-SNc) on neuromelanin magnetic resonance imaging (NM-MRI) and the specific binding ratio (SBR) on 123 I-N-v-fluoropropyl-2b-carbomethoxy3b-(4-iodophenyl)nortropane single photon emission computed tomography (DaT-SPECT) can be correlated with motor fluctuations (MFs) in advanced Parkinson's disease (PD) was investigated. METHODS: Thirty-five PD patients (60 ± 13 years) and 23 healthy individuals as controls (59 ± 19 years) were enrolled. The relationships between NM-MRI and DaT-SPECT were prospectively examined in two subgroups divided according to the presence or absence of MFs. Multivariate analysis was performed using the Cox proportional hazard model to screen for association factors. RESULTS: The NM-SNc size was correlated with the SBR (Spearman's ρ = 0.43, P < 0.05). The NM-SNc size was significantly reduced in PD with MFs compared with the subgroup without (P < 0.001), whereas the SBR did not significantly differ between the groups. NM-SNc size was a significant association factor for MFs (hazard ratio 0.94, P = 0.04). In receiver operating characteristic analysis of the factors for MF occurrence, the area under the receiver operating characteristic curve of the NM-SNc size showed a significant difference of 0.89 (P < 0.05) but no significant difference was found in the SBR. CONCLUSIONS: NM-SNc size was significantly correlated with the SBR in PD, but several factors in advanced PD were more closely associated with NM-SNc size than the SBR. NM-MRI might reflect the status of advanced PD more accurately than DaT-SPECT. Therefore, NM-MRI appears to provide a better marker for discriminating advanced PD than DaT-SPECT.


Assuntos
Melaninas/análise , Doença de Parkinson/diagnóstico , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Transtornos dos Movimentos/etiologia , Transtornos dos Movimentos/fisiopatologia , Estudos Prospectivos , Valores de Referência
18.
J Biol Chem ; 294(27): 10471-10489, 2019 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-31118223

RESUMO

Melanins are synthesized macromolecules that are found in all biological kingdoms. These pigments have a myriad of roles that range from microbial virulence to key components of the innate immune response in invertebrates. Melanins also exhibit unique properties with potential applications in physics and material sciences, ranging from electrical batteries to novel therapeutics. In the fungi, melanins, such as eumelanins, are components of the cell wall that provide protection against biotic and abiotic elements. Elucidation of the smallest fungal cell wall-associated melanin unit that serves as a building block is critical to understand the architecture of these polymers, its interaction with surrounding components, and their functional versatility. In this study, we used isopycnic gradient sedimentation, NMR, EPR, high-resolution microscopy, and proteomics to analyze the melanin in the cell wall of the human pathogenic fungus Cryptococcus neoformans We observed that melanin is assembled into the cryptococcal cell wall in spherical structures ∼200 nm in diameter, termed melanin granules, which are in turn composed of nanospheres ∼30 nm in diameter, termed fungal melanosomes. We noted that melanin granules are closely associated with proteins that may play critical roles in the fungal melanogenesis and the supramolecular structure of this polymer. Using this structural information, we propose a model for C. neoformans' melanization that is similar to the process used in animal melanization and is consistent with the phylogenetic relatedness of the fungal and animal kingdoms.


Assuntos
Parede Celular/metabolismo , Cryptococcus neoformans/metabolismo , Melaninas/química , Cryptococcus neoformans/classificação , Levodopa/química , Espectroscopia de Ressonância Magnética , Melaninas/análise , Melaninas/metabolismo , Microscopia Eletrônica de Transmissão , Nanopartículas/química , Tamanho da Partícula , Filogenia , Proteômica
19.
Sci Total Environ ; 673: 237-244, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-30991315

RESUMO

Intraspecific diversity buffers populations from deleterious impacts of environmental change. Nevertheless, the consequences of climate warming for phenotypic and genetic diversity within populations and species remain poorly understood. The goal of our study was to explore among-year variations in the phenotypic structure of populations and their relationships with climate variability and population dynamics. We analysed multiyear (1992-2018) data on colour morph frequencies within populations of the leaf beetle, Chrysomela lapponica, from multiple sites in the Kola Peninsula (northwestern Russia). We observed a strong decline in the proportion of dark (melanic) morphs among overwintered beetles during the study period; this decline was consistent across all study sites. Using model selection procedures, we explained declines in the dark morph of overwintered beetles by increases in minimum spring (May-June) daily temperatures. Other climatic characteristics, pollution load, and beetle population density were unrelated to variation in colour morph frequencies. Among newly emerged beetles (August), dark morph frequencies also decreased with an increase in average spring temperatures, but were unrelated to mean temperatures during the larval development period (July). These results suggest that the two-fold decline in dark morph frequencies during the past 26 years has been driven by the 2.5 °C increase in spring temperatures, most likely because dark males lose the mating advantages over light males that they obtain during cold springs. The continued loss of dark morphs and related decrease in within-population diversity may render leaf beetle populations more vulnerable to future environmental changes, in particular to those expressed in extreme weather fluctuations. Our study demonstrates that declines in within-population diversity are already underway in subarctic areas, and that these declines are likely driven by climate warming.


Assuntos
Mudança Climática , Besouros/fisiologia , Aquecimento Global , Melaninas/análise , Animais , Cor , Monitoramento Ambiental , Dinâmica Populacional , Federação Russa
20.
Photodermatol Photoimmunol Photomed ; 35(6): 415-419, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31006159

RESUMO

BACKGROUND: The main chromophores of human skin are melanins and hemoglobins along with carotenoids, bilirubin, and other compounds. In an effort to study the spectral signatures of skin melanin, we measured absorption spectra in a variety of situations, including a method to show early signs of re-pigmentation in vitiligo. METHODS: To measure skin in vivo, the essential component was a "Bifurcated Optical Fiber" with one end connected to the light source and the second end connected to the spectrometer while the common end was placed on the skin. RESULTS: In a typical in situ "melanin in skin" spectrum, the absorbance values first rise gradually, from 750 to 600 nm, then rise moderately from 600 to 450 nm, and rise sharply from 450 nm to a broad peak at 335 nm, below which it gradually rolls down to much lower values. CONCLUSION: We successfully studied melanin spectroscopically in subjects with vitiligo lesions, obtaining the differential spectra. Higher melanin levels can be shown by steeper negative slopes of a straight line fitted between 620 and 720 nm. Also, absorption peak at 335 nm showed the presence of melanin.


Assuntos
Epiderme/química , Melaninas/análise , Pigmentação da Pele , Vitiligo/metabolismo , Humanos , Espectrofotometria
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...