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BACKGROUND: Most of large epidemiological studies on melanoma susceptibility have been conducted on fair skinned individuals (US, Australia and Northern Europe), while Southern European populations, characterized by high UV exposure and dark-skinned individuals, are underrepresented. OBJECTIVES: We report a comprehensive pooled analysis of established high- and intermediate-penetrance genetic variants and clinical characteristics of Mediterranean melanoma families from the MelaNostrum Consortium. METHODS: Pooled epidemiological, clinical and genetic (CDKN2A, CDK4, ACD, BAP1, POT1, TERT, and TERF2IP and MC1R genes) retrospective data of melanoma families, collected within the MelaNostrum Consortium in Greece, Italy and Spain, were analysed. Univariate methods and multivariate logistic regression models were used to evaluate the association of variants with characteristics of families and of affected and unaffected family members. Subgroup analysis was performed for each country. RESULTS: We included 839 families (1365 affected members and 2123 unaffected individuals). Pathogenic/likely pathogenic CDKN2A variants were identified in 13.8% of families. The strongest predictors of melanoma were ≥2 multiple primary melanoma cases (OR 8.1; 95% CI 3.3-19.7), >3 affected members (OR 2.6; 95% CI 1.3-5.2) and occurrence of pancreatic cancer (OR 4.8; 95% CI 2.4-9.4) in the family (AUC 0.76, 95% CI 0.71-0.82). We observed low frequency variants in POT1 (3.8%), TERF2IP (2.5%), ACD (0.8%) and BAP1 (0.3%). MC1R common variants (≥2 variants and ≥2 RHC variants) were associated with melanoma risk (OR 1.4; 95% CI 1.0-2.0 and OR 4.3; 95% CI 1.2-14.6, respectively). CONCLUSIONS: Variants in known high-penetrance genes explain nearly 20% of melanoma familial aggregation in Mediterranean areas. CDKN2A melanoma predictors were identified with potential clinical relevance for cancer risk assessment.
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Melanoma , Neoplasias Cutâneas , Humanos , Neoplasias Cutâneas/epidemiologia , Neoplasias Cutâneas/genética , Estudos Retrospectivos , Mutação , Predisposição Genética para Doença , Melanoma/epidemiologia , Melanoma/genética , Melanoma/patologia , Inibidor p16 de Quinase Dependente de Ciclina/genética , Mutação em Linhagem Germinativa , Receptor Tipo 1 de Melanocortina/genéticaRESUMO
We studied the proton-rich T_{z}=-1 nucleus ^{70}Kr through inelastic scattering at intermediate energies in order to extract the reduced transition probability, B(E2;0^{+}â2^{+}). Comparison with the other members of the A=70 isospin triplet, ^{70}Br and ^{70}Se, studied in the same experiment, shows a 3σ deviation from the expected linearity of the electromagnetic matrix elements as a function of T_{z}. At present, no established nuclear structure theory can describe this observed deviation quantitatively. This is the first violation of isospin symmetry at this level observed in the transition matrix elements. A heuristic approach may explain the anomaly by a shape change between the mirror nuclei ^{70}Kr and ^{70}Se contrary to the model predictions.
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BACKGROUND: MC1R polymorphisms interact with CDKN2A mutations modulating melanoma risk and contribute to a less suspicious clinical and dermoscopic appearance of melanomas. Different strategies, including dermoscopic comparative approach and digital monitoring, are used for the melanoma diagnosis in this context. OBJECTIVE: To analyse the diagnostic accuracy of the morphologic approach and comparative approach in dermoscopy, and to detect melanoma in familial melanoma (FamMM) patients according to different genetic backgrounds. METHODS: Two independent readers evaluated 415 lesions belonging to 25 FamMM: 26 melanomas (62% in situ, 36% early invasive) and 389 naevi, blinded for dermoscopic and histopathologic diagnosis, following two different steps. First step-Randomized: all lesions were randomly located in one single folder. Second step-Comparative approach: the lesions were clustered by patient. Sensitivity, specificity and number needed to excise (NNE) for melanoma diagnosis were calculated for both diagnostic strategies. Sensitivity and specificity were also assessed regarding the genetic background. RESULTS: The comparative approach showed lower sensitivity compared to the morphologic approach (69.2 and 73.1 vs. 76.9 both readers) but better specificity (95.9 and 95.1 vs. 84.3 and 90.2, respectively). NNE was better in the comparative approach. The readers had more difficulties diagnosing lesions from CDKN2A mutation carriers with red hair colour (RHC) MC1R variants. CONCLUSION: The comparative approach can be useful in high-risk patients to decrease the NNE. Early melanomas in CDKN2A carriers with RHC polymorphisms are more difficult to diagnose even with the comparative approach and benefit from the detection of changes during digital dermoscopy monitoring for early diagnosis.
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Melanoma , Neoplasias Cutâneas , Dermoscopia , Diagnóstico Precoce , Genótipo , Humanos , Melanoma/diagnóstico , Melanoma/genética , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/genéticaRESUMO
BACKGROUND: The p.V600E mutation in the BRAF protein is the most frequent mutation in cutaneous melanoma and is a recurrent alteration found in common benign naevi. Analysis of the cell-free BRAF c.1799T>A, p.V600E mutation (cfBRAFV 600E ) in plasma has emerged as a biomarker for monitoring prognosis and treatment response in patients with melanoma. OBJECTIVES: To quantify cfBRAFV 600E levels in plasma from patients with melanoma and from patients without melanoma undergoing regular follow-up of their melanocytic lesions, in order to assess the clinical significance of the test. METHODS: We quantified cfBRAFV 600E by droplet digital polymerase chain reaction in plasma from 146 patients without melanoma undergoing continuous dermatological screening, from 26 stage III and seven stage IV patients with BRAF-mutant melanoma, and from 32 patients with melanoma who were free of disease for 3 or more years. RESULTS: Among disease-free patients and individuals without melanoma, 52% presented a high naevus count (> 50) and 49% had clinically atypical naevi. cfBRAFV 600E was detected in 71% of patients with stage IV melanoma and 15% with stage III, and in 1·4% of individuals without melanoma. No cfBRAFV 600E mutation was detected in disease-free patients with melanoma. Individuals without melanoma had lower cfBRAFV 600E levels than patients with melanoma. We established a variant allelic frequency of 0·26% or 5 copies mL-1 of cfBRAFV 600E as the optimal cutoff value for identifying patients with melanoma with > 99% specificity. CONCLUSIONS: This study suggests that naevus-related factors do not influence the detection of cfBRAFV 600E in individuals without melanoma, and supports the clinical diagnostic value of plasma cfBRAFV 600E quantification in patients with melanoma. What's already known about this topic? The analysis of the BRAF c.1799T>A (p.V600E) mutation in cell-free (cf)DNA has emerged as a potential biomarker for monitoring prognosis and treatment response in patients with metastatic BRAFV600E melanoma. The BRAFV600E alteration is a common genetic alteration found in benign proliferations such as melanocytic naevi. No information exists about the impact of the number of common acquired naevi or the presence of clinically atypical naevi in cfBRAFV600E detection in an individual. What does this study add? The cfBRAFV600E mutation is detected in plasma from a reduced number of individuals without melanoma undergoing continuous dermatological follow-up. A high number of naevi or the presence of clinically atypical naevi are factors that do not influence cfBRAFV600E detection in an individual. Both total cfBRAF concentration and cfBRAFV600E frequency are effective biomarkers in patients with advanced melanoma but not in patients at early stages or with micrometastases. What is the translational message? Detection of cfBRAFV600E in an individual is not influenced by naevus-related factors. cfBRAFV600E is a robust and reliable biomarker that can be used in dermatological surveillance programmes.
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Melanoma , Nevo Pigmentado , Proteínas Proto-Oncogênicas B-raf , Neoplasias Cutâneas , Humanos , Melanoma/diagnóstico , Melanoma/genética , Mutação/genética , Nevo Pigmentado/genética , Reação em Cadeia da Polimerase , Proteínas Proto-Oncogênicas B-raf/análise , Proteínas Proto-Oncogênicas B-raf/genética , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/genéticaRESUMO
BACKGROUND: Germline mutations in telomere-related genes such as POT1 and TERT predispose individuals to familial melanoma. OBJECTIVES: To evaluate the prevalence of germline mutations in POT1 and TERT in a large cohort of Spanish melanoma-prone families (at least two affected first- or second-degree relatives). METHODS: Overall, 228 CDKN2A wild-type melanoma-prone families were included in the study. Screening of POT1 was performed in one affected person from each family and TERT was sequenced in one affected patient from 202 families (26 families were excluded owing to DNA exhaustion/degradation). TERT promoter sequencing was extended to an additional 30 families with CDKN2A mutation and 70 patients with sporadic multiple primary melanoma (MPM) with a family history of other cancers. RESULTS: We identified four families with potentially pathogenic POT1 germline mutations: a missense variant c.233T>C (p.Ile78Thr); a nonsense variant c.1030G>T (p.Glu344*); and two other variants, c.255G>A (r.125_255del) and c.1792G>A (r.1791_1792insAGTA, p.Asp598Serfs*22), which we confirmed disrupted POT1 mRNA splicing. A TERT promoter variant of unknown significance (c.-125C>A) was detected in a patient with MPM, but no germline mutations were detected in TERT promoter in cases of familial melanoma. CONCLUSIONS: Overall, 1·7% of our CDKN2A/CDK4-wild type Spanish melanoma-prone families carry probably damaging mutations in POT1. The frequency of TERT promoter germline mutations in families with melanoma in our population is extremely rare.
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Predisposição Genética para Doença , Melanoma/genética , Regiões Promotoras Genéticas/genética , Neoplasias Cutâneas/genética , Telomerase/genética , Proteínas de Ligação a Telômeros/genética , Adulto , Idoso , Códon sem Sentido , Estudos de Coortes , Inibidor p16 de Quinase Dependente de Ciclina/genética , Análise Mutacional de DNA , Feminino , Testes Genéticos , Mutação em Linhagem Germinativa , Humanos , Masculino , Anamnese , Melanoma/epidemiologia , Pessoa de Meia-Idade , Mutação , Mutação de Sentido Incorreto , Linhagem , Complexo Shelterina , Neoplasias Cutâneas/epidemiologia , Espanha/epidemiologia , Melanoma Maligno CutâneoRESUMO
First described in 1961, photoonycholysis (PO) is a rare nail alteration that may result from drug intake, from topical aminolevulinate photodynamic therapy or from photosensitive conditions such as porphyria or pseudoporphyria. Spontaneous PO is rare. This review updates the numerous causes of PO and highlights some new ways producing this condition. Four different types of PO are clearly recognized without relationship with the responsible drug. An updated list of potential inducing drug is provided. Some practical points on PO have been raised. The inability to reproduce photoonycholysis experimentally should be emphasized, and the pathogenesis of PO still needs to be clarified.
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Antibacterianos/efeitos adversos , Furocumarinas/efeitos adversos , Onicólise/etiologia , Terapia PUVA/efeitos adversos , Porfirias/complicações , Humanos , Fotoquimioterapia/efeitos adversos , Fármacos Fotossensibilizantes/efeitos adversosRESUMO
Congenital erythropoietic porphyria is a rare autosomal recessive disease caused by a deficiency of uroporphyrinogen III synthase, owing to mutations in UROS in chromosome 10. Occasionally, patients show a mild, late-onset disease, without germline UROS mutations, associated with haematological malignancies. We report a 65-year-old patient with photosensitivity, overexcretion of porphyrins and thrombocytopenia. Bone marrow analysis gave a diagnosis of myelodysplastic syndrome (MDS) with the presence of a derivative chromosome 3, possibly due to an inversion including 3q21 and 3q26 break points. After allogeneic stem-cell transplantation, complete remission of MDS and uroporphyria was achieved. To our knowledge, this is the first reported case of acquired erythropoietic uroporphyria associated with MDS, with chromosome 3 alterations.
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Cromossomos Humanos Par 3/genética , Transtornos de Início Tardio/diagnóstico , Síndromes Mielodisplásicas/diagnóstico , Porfiria Eritropoética/diagnóstico , Idoso , Antimetabólitos Antineoplásicos/uso terapêutico , Azacitidina/uso terapêutico , Transfusão de Sangue , Medula Óssea/patologia , Transplante de Medula Óssea , Inversão Cromossômica , Humanos , Transtornos de Início Tardio/etiologia , Transtornos de Início Tardio/patologia , Transtornos de Início Tardio/terapia , Masculino , Síndromes Mielodisplásicas/complicações , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/terapia , Porfiria Eritropoética/etiologia , Porfiria Eritropoética/patologia , Porfiria Eritropoética/terapia , Porfirinas/sangue , Porfirinas/urina , Pele/patologia , Resultado do TratamentoRESUMO
INTRODUCTION: Polymorphic light eruption (PLE) is a common idiopathic photodermatosis that typically presents with pruritic papular or papulovesicular lesions on sun-exposed skin between spring and autumn. In many subjects PLE is mild, and can usually be prevented by the use of broad-spectrum topical sunscreens and a gradual increase in sunlight exposure. However, in some individuals, sunlight exposure results in florid PLE and they often benefit from prophylactic desensitization treatment using phototherapy in early spring, an artificial method that induces a "hardening" phenomenon. OBJECTIVE: To describe and evaluate the efficacy of a short desensitization protocol, based on a one-month-treatment, administered twice a week with narrow band UVB in subjects with severe polymorphic light eruption (PLE). METHODS: A retrospective, open planned and non-randomized study to assess the efficacy of UVB phototherapy in prevention of polymorphic light eruption. RESULTS: Fifteen subjects diagnosed with severe PLE were treated with the standard protocol in our Photobiology Unit between 2014 and 2015. The effect of hardening was sustained during follow up in 87.5% of desensitization treatments. A statistically significant association (p<0.05) between the years of duration of the PLE and the response to treatment was found. CONCLUSIONS: The effect of hardening was maintained in the vast majority of subjects, obtaining a good benefit with no PLE episodes during all the summer. We demonstrate that our standard protocol is effective, and produces a successful outcome for the majority of PLE subjects. Our protocol is shorter than those currently applied, being favourable both for the patient and the physician.
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Transtornos de Fotossensibilidade/radioterapia , Dermatopatias Genéticas/radioterapia , Terapia Ultravioleta/métodos , Adolescente , Adulto , Anticorpos Antinucleares/análise , Terapia Combinada , Seguimentos , Antagonistas dos Receptores Histamínicos/uso terapêutico , Humanos , Pessoa de Meia-Idade , Transtornos de Fotossensibilidade/tratamento farmacológico , Transtornos de Fotossensibilidade/imunologia , Estudos Retrospectivos , Estações do Ano , Pele/efeitos da radiação , Dermatopatias Genéticas/tratamento farmacológico , Dermatopatias Genéticas/imunologia , Luz Solar/efeitos adversos , Resultado do Tratamento , Adulto Jovem , beta Caroteno/uso terapêuticoRESUMO
BACKGROUND: Solar urticaria is a chronic inducible urticaria also classified as an idiopathic dermatosis. The objective of this paper is to define the phenotypic characteristics of solar urticaria and to evaluate its incidence. MATERIAL AND METHOD: This was a retrospective multicenter study in which data were gathered on the epidemiology and clinical, photobiologic, laboratory, and therapeutic characteristics of solar urticaria. RESULTS: A total of 224 patients (141 women and 83 men) were included from 9 photobiology units. The mean age of the patients was 37.9 years (range, 3-73 years). A history of atopy was detected in 26.7%, and the most common presentation was allergic rhinitis (16.5%). Clinical signs were limited to sun-exposed areas in 75.9% of patients. The light spectrum most commonly implicated was visible light only (31.7%), and in 21% of cases it was only possible to trigger solar urticaria with natural light. The treatments most widely used by photobiology experts were oral antihistamines (65.46%), followed by different forms of phototherapy (34%). Complete resolution was observed most often in patients with solar urticaria triggered exclusively by visible or natural light, with statistically significant differences with respect to other wavelengths (P<.05). No increase in the annual incidence of solar urticaria was observed. CONCLUSIONS: We have presented the largest series of solar urticaria published to date. The epidemiological, clinical, and photobiologic findings confirm previously reported data, although there was a particularly high rate of negative phototests in our series. Reactivity exclusively to visible or natural light was associated with a higher probability of resolution. No increasing trend was observed in the annual incidence.
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Transtornos de Fotossensibilidade/etiologia , Luz Solar/efeitos adversos , Urticária/etiologia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Antagonistas dos Receptores Histamínicos/uso terapêutico , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Fenótipo , Transtornos de Fotossensibilidade/epidemiologia , Transtornos de Fotossensibilidade/patologia , Transtornos de Fotossensibilidade/terapia , Fototerapia , Estudos Retrospectivos , Espanha/epidemiologia , Urticária/epidemiologia , Urticária/patologia , Urticária/terapia , Adulto JovemRESUMO
The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-Z target. Positron polarization up to 82% have been measured for an initial electron beam momentum of 8.19 MeV/c, limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community.
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In an experiment with the BigRIPS separator at the RIKEN Nishina Center, we observed two-proton (2p) emission from ^{67}Kr. At the same time, no evidence for 2p emission of ^{59}Ge and ^{63}Se, two other potential candidates for this exotic radioactivity, could be observed. This observation is in line with Q value predictions which pointed to ^{67}Kr as being the best new candidate among the three for two-proton radioactivity. ^{67}Kr is only the fourth 2p ground-state emitter to be observed with a half-life of the order of a few milliseconds. The decay energy was determined to be 1690(17) keV, the 2p emission branching ratio is 37(14)%, and the half-life of ^{67}Kr is 7.4(30) ms.
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Deficiency of uroporphyrinogen III synthase (UROS) causes congenital erythropoietic porphyria (CEP). The disease, originating from the inheritance of mutations within the UROS gene, presents a recessive form of transmission. In a few patients, a late-onset CEP-like phenotype without UROS mutations appears to be associated with a myelodysplastic syndrome. We report a 60-year-old man with late-onset signs of cutaneous porphyria and accumulation in urine, plasma and faeces of type I porphyrin isomers characteristic of CEP. Analysis of DNA from peripheral leucocytes, skin and bone marrow aspirate showed that he was a heterozygous carrier of a Cys73Arg (c.217 T>C) mutation within UROS. Sequencing of cDNA from peripheral blood confirmed heterozygosity and expression of the normal allele. Measurement of UROS enzymatic activity in erythrocytes showed values ~70% of normal, indirectly indicating expression of the normal allele. Differently from other cases of late-onset uroporphyria, the patient did not present thrombocytopenia or any evidence of a myelodysplastic syndrome. Five years of clinical follow-up showed persistence of skin signs and increased excretion of porphyrins, independently of lifestyle factors or changes in medication regimes. We hypothesize acquired mosaicism (in the bone marrow) affecting the UROS gene. Thus, unstable cellular clones initiated overproduction of isomer I porphyrins leading to a CEP phenotype. This could be explained either by a clonal expansion of the porphyric (Cys73Arg) allele or by loss of function of the normal allele. Cellular turnover would facilitate release of uroporphyrins into circulation and subsequent skin lesions. This is the first case of a CEP heterozygous carrier presenting clinical manifestations.
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Dermatoses da Mão/genética , Transtornos de Início Tardio/genética , Mutação de Sentido Incorreto/genética , Porfirias/genética , Uroporfirinogênio III Sintetase/genética , Heterozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Porfirinas/metabolismoRESUMO
We studied simultaneously the (4)He(e,e'p), (4)He(e,e'pp), and (4)He(e,e'pn) reactions at Q(2)=2(GeV/c)(2) and x(B)>1, for an (e,e'p) missing-momentum range of 400 to 830 MeV/c. The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A=2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum, in a region where the nucleon-nucleon (NN) force is expected to change from predominantly tensor to repulsive. The abundance of neutron-proton pairs is reduced as the nucleon momentum increases beyond â¼500 MeV/c. The extracted fraction of proton-proton pairs is small and almost independent of the missing momentum. Our data are compared with calculations of two-nucleon momentum distributions in (4)He and discussed in the context of probing the elusive repulsive component of the NN force.
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BACKGROUND: The identification of BRAF mutations in melanoma led to the development and implementation of new and effective therapies. Few clinical and histological features have been associated with this mutational status. OBJECTIVES: The main objective of this study was to investigate clinical, histopathological and dermoscopic characteristics of primary melanomas according to BRAF or NRAS mutational status. METHODS: An observational retrospective study including melanoma dermoscopy images assessed for somatic mutations in BRAF and NRAS. RESULTS: Seventy-two patients were included, 30 women (42%) and 42 men (58%), mean age was 59 ± 15.51 years. BRAF-mutated melanomas were more frequently located on the trunk (n = 18, 64% for BRAF-mutated vs. n = 11, 29% for wild-type melanomas, P = 0.013). Histological ulceration was associated with the presence of BRAF mutations [odds ratio (OR) 3.141; 95% confidence interval (CI) 1.289-7.655; P = 0.002]. The Breslow index tended to be thicker in BRAF-mutated compared with wild-type (P = 0.086). BRAF mutations were present in 28 (39%) patients and only four cases were positive for NRAS mutations (6%), BRAF and NRAS mutations being mutually exclusive. The presence of dermoscopic peppering was associated with MAPK mutations (BRAF and NRAS) (OR 1.68; 95% CI 1.089-2.581; P = 0.015). Dermoscopic ulceration was also associated with BRAF mutations excluding acral and facial melanomas (OR 2.64; 95% CI 1.032-6.754). CONCLUSIONS: This study showed a correlation between BRAF and NRAS status and dermoscopic findings of 'peppering' as an expression of regression and melanophages in the dermis, suggesting a morphological consequence of immune behaviour in BRAF-mutated melanomas.
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Genes ras/genética , Melanoma/genética , Mutação/genética , Proteínas Proto-Oncogênicas B-raf/genética , Neoplasias Cutâneas/genética , Dermoscopia , Feminino , Humanos , Masculino , Melanoma/patologia , Pessoa de Meia-Idade , Estudos Retrospectivos , Neoplasias Cutâneas/patologiaRESUMO
BACKGROUND: Phototesting is a technique that assesses the skin's sensitivity to UV radiation by determining the smallest dose of radiation capable of inducing erythema (minimal erythema dose [MED]) and anomalous responses to UV-A radiation. No phototesting protocol guidelines have been published to date. METHODOLOGY: This was a multicenter prospective cohort study in which 232 healthy volunteers were recruited at 9 hospitals. Phototests were carried out with solar simulators or fluorescent broadband UV-B lamps. Each individual received a total of 5 or 6 incremental doses of erythemal radiation and 4 doses of UV-A radiation. The results were read at 24hours. RESULTS: At hospitals where solar simulators were used, the mean (SD) MED values were 23 (8), 28 (4), 35 (4), and 51 (6) mJ/cm(2) for skin phototypes i to iv, respectively. At hospitals where broadband UV-B lamps were used, these values were 28 (5), 32 (3), and 34 (5) mJ/cm(2) for phototypes ii to iv, respectively. MED values lower than 7, 19, 27, and 38 mJ/cm(2) obtained with solar simulators were considered to indicate a pathologic response for phototypes I to IV, respectively. MED values lower than 18, 24, and 24mJ/cm(2) obtained with broadband UV-B lamps were considered to indicate a pathologic response for phototypes ii to iv, respectively. No anomalous responses were observed at UV-A radiation doses of up to 20J/cm(2). CONCLUSIONS: Results were homogeneous across centers, making it possible to standardize diagnostic phototesting for the various skin phototypes and establish threshold doses that define anomalous responses to UV radiation.
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Eritema/classificação , Eritema/etiologia , Pele/efeitos da radiação , Raios Ultravioleta , Adulto , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Testes Cutâneos , Luz Solar , Adulto JovemRESUMO
BACKGROUND: Cutaneous melanoma tumour is classified into clinicohistopathological subtypes that may be associated with different genetic and host factors. Variation in the MC1R gene is one of the main factors of risk variation in sporadic melanoma. The relationship between MC1R variants and the risk of developing a specific subtype of melanoma has not been previously explored. OBJECTIVES: To analyse whether certain MC1R variants are associated with particular melanoma subtypes with specific clinicohistopathological features. METHODS: An association study was performed between MC1R gene variants and clinicopathological subtypes of primary melanoma derived from 1679 patients. RESULTS: We detected 53 MC1R variants (11 synonymous and 42 nonsynonymous). Recurrent nonsynonymous variants were p.V60L (30·0%), p.V92M (11·7%), p.D294H (9·4%), p.R151C (8·8%), p.R160W (6·2%), p.R163Q (4·2%) p.R142H (3·3%), p.I155T (3·8%), p.V122M (1·5%) and p.D84E (1·0%). Melanoma subtypes showed differences in the total number of MC1R variants (P = 0·028) and the number of red hair colour variants (P = 0·035). Furthermore, an association between p.R163Q and lentigo maligna melanoma was detected under a dominant model of heritance (odds ratio 2·16, 95% confidence interval 1·07-4·37; P = 0·044). No association was found between p.R163Q and Fitzpatrick skin phototype, eye colour or skin colour, indicating that the association was independent of the role of MC1R in pigmentation. No association was observed between MC1R polymorphisms and other melanoma subtypes. CONCLUSIONS: Our findings suggest that certain MC1R variants could increase melanoma risk due to their impact on pathways other than pigmentation, and may therefore be linked to specific melanoma subtypes.
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Sarda Melanótica de Hutchinson/genética , Melanoma/genética , Polimorfismo Genético/genética , Receptor Tipo 1 de Melanocortina/genética , Neoplasias Cutâneas/genética , Cor de Olho/genética , Variação Genética/genética , Cor de Cabelo/genética , Humanos , Região do Mediterrâneo/etnologia , Melanoma/etnologia , Nucleotídeos/genética , Fenótipo , Estudos Retrospectivos , Fatores de Risco , Neoplasias Cutâneas/etnologia , Melanoma Maligno CutâneoRESUMO
Previous studies describe six factors accounting for interspecific diversity of electric organ discharge (EOD) waveforms in Gymnotus. At the cellular level, three factors determine the locally generated waveforms: (1) electrocyte geometry and channel repertoire; (2) the localization of synaptic contacts on electrocyte surfaces; and (3) electric activity of electromotor axons preceding the discharge of electrocytes. At the organismic level, three factors determine the integration of the EOD as a behavioral unit: (4) the distribution of different types of electrocytes and specialized passive tissue forming the electric organ (EO); (5) the neural mechanisms of electrocyte discharge coordination; and (6) post-effector mechanisms. Here, we reconfirm the importance of the first five of these factors based on comparative studies of a wider diversity of Gymnotus than previously investigated. Additionally, we report a hitherto unseen aspect of EOD diversity in Gymnotus. The central region of the EO (which has the largest weight on the conspecific-received field) usually exhibits a negative-positive-negative pattern where the delay between the early negative and positive peaks (determined by neural coordination mechanisms) matches the delay between the positive and late negative peaks (determined by electrocyte responsiveness). Because delays between peaks typically determine the peak power frequency, this matching implies a co-evolution of neural and myogenic coordination mechanisms in determining the spectral specificity of the intraspecific communication channel. Finally, we define four functional species groups based on EO/EOD structure. The first three exhibit a heterogeneous EO in which doubly innervated electrocytes are responsible for a main triphasic complex. Group I species exhibit a characteristic cephalic extension of the EO. Group II species exhibit an early positive component of putative neural origin, and strong EO auto-excitability. Group III species exhibit an early, slow, negative wave of abdominal origin, and variation in EO auto-excitability. Representatives of Group IV generate a unique waveform comprising a main positive peak followed by a small, load-dependent negative component.
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Órgão Elétrico/anatomia & histologia , Órgão Elétrico/fisiologia , Gimnotiformes/anatomia & histologia , Gimnotiformes/fisiologia , Animais , Evolução Biológica , Órgão Elétrico/citologia , Órgão Elétrico/inervação , Especificidade da EspécieRESUMO
Recombinant protein purification with affinity tags is a widely employed technique. One of the most common tags used for protein purification is the histidine tag (Histag). In this work, we use a tandem starch-binding domain (SBDtag) as a tag for protein purification. Four proteins from different sources were fused to the SBDtag, and the resulting fusion proteins were purified by affinity chromatography using the Histag or the SBDtag. The results showed that the SBDtag is superior to the Histag for protein purification. The efficient adsorption of the fusion proteins to raw corn starch was also demonstrated, and two fusions were selected to test purification directly using raw starch from rice, corn, potato, and barley. The two fusion proteins were successfully recovered from crude bacterial extract using raw starch, thus demonstrating that the SBDtag can be used as an efficient affinity tag for recombinant protein purification on an inexpensive matrix.