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In recent years, some treatments for esthetic and pathologic skin conditions have increasingly been based on the use of non-ablative neodymium-doped yttrium aluminum garnet (Nd:YAG) laser due to its greater penetration ability than other types of lasers, few contraindications, minimal side effects, no damage for epidermidis and the rapid recovery of the treated patients. The skin is frequently exposed to many stressors such as radiation, toxic substances, metabolites, foods, mechanical insults, and allergen exposition that cause oxidative damage and have a decisive influence on the aging process. The imbalance between reactive oxygen species, reactive nitrogen species, and the malfunctioning of the antioxidant defense system promotes the establishment of an excessive inflammatory process, which can induce various diseases including cancer and neurodegenerative disorders. The present study investigated the cytoprotective function of Q-switched Nd:YAG laser against stress aging and cell injury in HaCaT cells. We evaluated the effect of the laser on antioxidant defenses, inflammation, metalloproteinases' expression, and the AhR-Nrf2 pathway. Q-switched Nd:YAG is able to upregulate the AhR pathway and the expression of IL-6 and TGF-ß, which are involved in wound repair process, and to downregulate the expression of MMP-2 and 9, so preventing the collagen degradation. Q-switched Nd:YAG can stimulate the cellular antioxidant defenses by activating the AhR-Nrf2 system.
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Lasers de Estado Sólido , Humanos , Lasers de Estado Sólido/uso terapêutico , Fator 2 Relacionado a NF-E2 , Antioxidantes , Queratinócitos/efeitos da radiação , Inflamação/radioterapia , Inflamação/patologia , Estresse OxidativoRESUMO
During the last years, several attempts have been accomplished to improve the wound healing. Device application aimed at enhancing skin ability to reconstruct its damaged sites through a proper dermal regenerative process. In particular, Q-switched Nd-YAG laser (Medlite C6 laser, Conbio, USA) applied with a fluence of 8 J/cm2, a pulse width of 5 ns, and a spot size of 4 mm exerts a photo-mechanical action that improve skin repair. Besides, hyaluronan hybrid cooperative complexes (HCC) widely exploited in dermoesthetic applications proved specific actions on keratinocytes and fibroblasts monolayer repair. We evaluated this specific laser treatment in vitro on a wound healing model based on human keratinocytes (HaCaT) alone and in combination with HCC. In addition, we evaluated key biomarkers of dermal repair. Scratched HaCaT monolayers were treated with laser and successively with HA-based formulations (HHA and HCC). For each treatment and the control samples, at least 3 different wells were analyzed. Wound closure was quantified, measuring five view filed for each well at increasing incubation time, exploiting time lapse videomicroscopy and image analysis, permitting to compare the different healing rate of treatments respect to control. By real-time PCR and western blotting, we evaluated biomarkers of wound regeneration, such as integrins, aquaporin three (AQP3), and proinflammatory cytokines. The ANOVA test was used to assess statistical significance of the results obtained. Laser-treated cells achieved wound closure in about 37 h, faster than the control, while when coupled to HCC, the complete reparation was obtained in 24 h. Integrin αV was upregulated by treatments, with in particular about four-fold increase respect to the control when HCC + laser was used. In addition, integrin ß3 was upregulated by all treatments especially with the combination of laser and HCC proved more efficient than others (~ 14-folds). A slighter but significant increase of AQP3 gene expression of 61% was found for laser treatment while the latter combined with HCC determined an upregulation of 72%. By coupling laser treatment and HCC, further healing improvement and consistent biomarker modulation was observed. Our results may support clinical implementation of new dermatology protocols conjugating laser treatments with topical or injective HA formulations as a valid tool in treatments to repair scars or other skin defects.
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Ácido Hialurônico/farmacologia , Queratinócitos/efeitos dos fármacos , Queratinócitos/efeitos da radiação , Lasers de Estado Sólido/uso terapêutico , Cicatrização/efeitos dos fármacos , Biomarcadores/metabolismo , Géis , Humanos , Queratinócitos/citologia , Queratinócitos/metabolismoRESUMO
BACKGROUND: Surgical blepharoplasty is one of the most common plastic surgical procedures performed worldwide. It is carried out for treating both aesthetic and functional indications. As with any surgical procedures, the technique is not free from complications. The growing request for non-invasive, effective procedures, and safe technology for aesthetic treatments of eyelids has implied the research for novel treatment strategies marked by a good efficacy and less collateral effects when compared to surgical procedures. The choice fell on the relatively recent plasma skin regeneration technique. AIMS: The aim of this study is to evaluate the effectiveness of plasma radiofrequency ablation in non-surgical blepharoplasty performed with DAS Medical device (Technolux), a tool working with long-wave plasma radiofrequency principles. PATIENTS/METHODS: Ten patients affected by aesthetically unpleasant dermatochalasis, excess of tissue and fine wrinkles of the eyelids, were enrolled for non-surgical blepharoplasty with long-wave plasma radiofrequency ablation device. The treatment consisted of two sessions carried out at interval of 30 days. RESULTS: Treatments were well tolerated by all patients with no adverse effects and optimal aesthetic results. CONCLUSIONS: The technique consists of a modeling of the eyelids that must be sculpted reducing excess of skin, improving the appearance of eyelids, rejuvenating the eyes, and reducing eyelid heaviness. Long-wave plasma radiofrequency ablation could be an effective treatment for non-surgical blepharoplasty, and could offer an alternative choice to surgical procedures for aesthetic treatments of eyelids.
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Blefaroplastia/métodos , Ablação por Cateter/métodos , Pálpebras/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Adulto , Idoso , Blefaroplastia/efeitos adversos , Ablação por Cateter/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Gases em Plasma/uso terapêutico , Procedimentos de Cirurgia Plástica/efeitos adversos , Envelhecimento da Pele , Resultado do TratamentoRESUMO
BACKGROUND: In the latest few years, plasma radiofrequency ablation has turned out a good option for treatment of several benign skin lesions. The technique can be easily performed to treat skin lesions with limited tissue invasion and no residual scars or hypo/hyperpigmentation areas. OBJECTIVE: The aim of this study was to assess the effects of plasma radiofrequency ablation in treatment of benign skin lesions, through clinical and reflectance confocal microscopy outcomes. METHODS: Six patients who presented benign skin lesions underwent long-wave plasma radiofrequency ablation treatment with DAS medical device (Technolux, Italia). Reflectance confocal microscopy analysis was performed at baseline and after 1 month. RESULTS: The treatment was well tolerated; only a slight erythema and a thin crust on the treated area were referred for 3-7 days after treatment. After one month from treatments, we observed the complete disappearance of the lesions and no significant signs of inflammation, redness, hypo/hyperpigmentation, or scars on the site of the treated areas; these clinical data were also confirmed by reflectance confocal microscopy analysis. CONCLUSIONS: Long-wave plasma radiofrequency ablation actually can be considered a well-tolerated, painless, safe, effective, and low-cost procedure for skin treatments.
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Ablação por Cateter/métodos , Microscopia Confocal/métodos , Neoplasias Cutâneas , Feminino , Humanos , Masculino , Pele/diagnóstico por imagem , Pele/patologia , Neoplasias Cutâneas/diagnóstico por imagem , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/terapia , Resultado do TratamentoRESUMO
Skin represents an interface between internal and external environment; it protects human body by regulating the water loss and the maintenance of body temperature, defending against irritant and pathogen agents, and against physical, chemical, and UV damage. It provides to essential physiological functions, such as the important antioxidant defense capacity; its protective/defensive function is performed by a high number of proteins, and shows important functions in maintenance of skin barrier homeostasis. Keratinocytes and fibroblasts play a pivotal role to determine or prevent skin aging in response to intrinsic or extrinsic stimuli, modulating cytokines and several biochemical factors. Non-ablative technologies are playing an increasing role in the management of skin aging, inducing a dermal remodeling without a visible epidermal damage. The objective of this study was to evaluate the effect of Q-switched 1064 Nd-YAG laser (Medlite Conbio C6 Nd-YAG laser, Cynosure USA) in skin barrier function, analyzing the constituents which are strongly altered in aging skin. Particularly, we evaluated the expression of filaggrin, TGase, HSP70, and aquaporins, on HaCaT cells. The expression of proinflammatory cytokines has been investigated too.As a second step of the study, we analyzed the modulation of the rejuvenation molecular markers on human skin fibroblasts (HDFs) stimulated with keratinocytes conditioned medium (KCM).Our results demonstrated that Q-switched 1064 nm Nd:YAG laser acts on the skin barrier function, increasing the expression of aquaporins, filaggrin, TGase, and HSP70, modulating the proinflammatory cytokines. In fibroblasts stimulated with keratinocytes conditioned medium (KCM) and irradiated with Q-switched 1064 nm Nd:YAG laser, we can observe a reduction of MMP-1 and an increase in procollagen, collagen type I, and elastin. Our results highlight that Q-switched 1064 nm Nd:YAG laser treatment could represent an effective weapon to fight skin aging.
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Biomarcadores/metabolismo , Comunicação Celular , Fibroblastos/efeitos da radiação , Queratinócitos/efeitos da radiação , Lasers de Estado Sólido/uso terapêutico , Rejuvenescimento , Pele/efeitos da radiação , Comunicação Celular/efeitos da radiação , Linhagem Celular , Sobrevivência Celular/efeitos da radiação , Citocinas/genética , Citocinas/metabolismo , Fibroblastos/citologia , Proteínas Filagrinas , Regulação da Expressão Gênica/efeitos da radiação , Humanos , Mediadores da Inflamação/metabolismo , Queratinócitos/citologia , Envelhecimento da Pele/efeitos da radiação , ÁguaRESUMO
Cytochrome P450 CYP1A1 and CYP1B1 enzymes are regulated by the aryl hydrocarbon receptor (AhR), a transcription factor activated by a variety of ligands among which Malassezia metabolites. In this study, we analyzed the modulation of CYP1A1, CYP1B1, and AhR in human keratinocytes infected with different strains of Malassezia pachydermatis, as well as the upregulation of some genes involved in the epidermal homeostasis. We demonstrated that all the strains induced AhR activation and its nuclear translocation in HaCaT cells infected for 24 h, compared to untreated cells. The expression of CYP1A1 and CYP1B1, prototypical markers of the AhR signaling pathway, were upregulated with the level of CYP1A1 mRNA approximately 100-fold greater than that for CYP1B1. Filaggrin, involucrin, and TGaseI, proteins involved in epidermal differentiation, were all modulated by Malassezia pachydermatis strains, with the strongest induction observed for filaggrin. By contrast, quinone oxidoreductase 1 (NQO1), which is part of the antioxidant defense system involved in detoxification, was not modulated in our experimental model. In conclusions, our findings suggest that Malassezia pachydermatis infection of human keratinocytes induces activation of the AhR, and increases the expression of its responsive genes and markers of epidermal differentiation, paving the way for occurrence/exacerbation of pathological skin conditions.
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Fatores de Transcrição Hélice-Alça-Hélice Básicos/biossíntese , Citocromo P-450 CYP1A1/biossíntese , Queratinócitos/metabolismo , Queratinócitos/microbiologia , Malassezia/crescimento & desenvolvimento , Receptores de Hidrocarboneto Arílico/biossíntese , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Linhagem Celular , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1B1/biossíntese , Citocromo P-450 CYP1B1/genética , Proteínas Filagrinas , Perfilação da Expressão Gênica , Humanos , RNA Mensageiro/análise , RNA Mensageiro/genética , Receptores de Hidrocarboneto Arílico/genética , Transcrição GênicaRESUMO
In the published online version of the article, the authors' given and family names were incorrectly captured. The corrected names are shown in the author group section above.
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Candida albicans is an opportunistic pathogen commensal in the oral cavity, vagina, and healthy skin. Common therapeutic options for fungal infections are topical or systemic antifungal drugs. Recently, in cutaneous pathologies, lasers and light-based treatments have emerged showing few contraindications and minimal side effects. The Q-switched (Nd-YAG) laser at a wavelength of 1064 nm has been shown to be useful in dermatology, dentistry, and some other medical specialties. It is used to treat onychomycoses, warts, and wounds and in some other treatments. We analyzed the effect of Q-switched (Nd-YAG) laser 1064 nm on human keratinocytes infected with C. albicans. In particular, we evaluated the effect of laser on invasiveness of C. albicans and on inflammatory and protective response of HaCaT cells infected. The results obtained did not show inhibitory, fungicidal, or fungistatic effects of laser on yeast; in addition, laser did not affect HaCaT vitality. HaCaT cells infected with C. albicans and irradiated with laser showed a reduction of invasiveness of TNF-α and IL8 gene expression and an increase of immunomodulatory cytokines such as TGFß. Furthermore, laser induces a significant over-expression of HSP70B (heat shock protein) and of HBD-2 (Human ß defensin-2) in HaCaT infected with C. albicans, compared to the untreated control. The use of Q-switched Nd:YAG laser in skin mycosis caused by C. albicans reduces yeast invasiveness in keratinocytes, downregulates inflammatory activities, and facilitates cytoprotection and antimicrobial defense. Our results offer a promising therapeutic strategy in the management of skin candidiasis, also in combination with conventional therapies.
Assuntos
Candida albicans/efeitos da radiação , Imunidade Inata/efeitos da radiação , Queratinócitos/imunologia , Queratinócitos/microbiologia , Lasers de Estado Sólido/uso terapêutico , Linhagem Celular , Sobrevivência Celular/efeitos da radiação , Feminino , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Humanos , Inflamação/patologia , Queratinócitos/patologia , Queratinócitos/efeitos da radiação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Regulação para Cima/efeitos da radiação , beta-Defensinas/genética , beta-Defensinas/metabolismoRESUMO
Defensins are a group of antimicrobial peptides (AMPs) found in different living organisms, and are involved in the first line of defense in the innate immune response against pathogens. The increase in the resistance of bacteria to conventional antibiotics and the need for new antibiotics has stimulated interest in the use of AMPs as new therapeutic agents. The inducible nature of human defensin genes suggests that it is possible to increase the endogenous production by utilizing small molecules of various origins to enhance, even selectively, the expression of these peptides. In the light of their role in immunomodulation, angiogenesis, wound healing, inflammation and cancer, as well as their antimicrobial activity, it is possible induce their expression or create analogs with increased specific activity or various degrees of selectivity, or obtain human defensins with genetic engineering to optimize the potency and safety in order to reduce cytotoxicity and potential proinflammatory activity and susceptibility to protease and salt. Restoring the balance between immunostimulating and immunosuppressive molecules may be an important strategy to correct expression defects in specific diseases.
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Fatores Imunológicos/farmacologia , Imunossupressores/farmacologia , beta-Defensinas/farmacologia , Animais , Tratamento Farmacológico , Humanos , Imunidade Inata , Fatores Imunológicos/química , Fatores Imunológicos/genética , Fatores Imunológicos/imunologia , Imunomodulação , Imunossupressores/química , Imunossupressores/imunologia , beta-Defensinas/química , beta-Defensinas/genética , beta-Defensinas/imunologiaRESUMO
Malassezia pachydermatis is a yeast belonging to the microbiota of the skin and mucous membranes of dog and cat, but it can also act as pathogen, causing dermatitis. The aim of this work was to evaluate the genetic variability of M. pachydermatis strains isolated from symptomatic dogs and cats and determine a correlation between genotype and phenotype. For this purpose eleven strains of M. pachydermatis were molecularly classified by nested-polymerase chain reaction (nested-PCR) based on ITS-1 and ITS-2 regions, specific for fungal rRNA genes. Furthermore, random amplification of polymorphic DNA (RAPD) was applied for genetic typing of M. pachydermatis isolates identifying four different genotypes. Strains belonging to genotype 1 produced the highest amount of biofilm and phospholipase activity. The inflammatory response induced by M. pachydermatis strains in immortalized human keratinocytes (HaCat cells) was significantly different when we compared the results obtained from each strain. In particular, HaCat cells infected with the strains belonging to genotypes 1 and 2 triggered the highest levels of increase in TLR-2, IL-1ß, IL-6, IL-8, COX-2 and MMP-9 expression. By contrast, cells infected with the strains of genotype 3 and those of genotype 4 did not significantly induce TLR-2 and cytokines. The results obtained might suggest a possible association between genotype and virulence factors expressed by M. pachydermatis strains. This highlights the need for a more accurate identification of the yeast to improve the therapeutic approach and to monitor the onset of human infections caused by this emergent zoonotic pathogen.
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Doenças do Gato/microbiologia , Dermatomicoses/veterinária , Doenças do Cão/microbiologia , Malassezia/genética , Malassezia/metabolismo , Fatores de Virulência/metabolismo , Animais , Gatos , DNA Fúngico/genética , Dermatomicoses/microbiologia , Cães , Regulação Fúngica da Expressão Gênica , Variação Genética , Genótipo , Fatores de Virulência/genéticaRESUMO
Over the centuries, traditional Chinese medicine (TCM) and Western medicine have traveled along parallel lines with no opportunity for collaboration. In recent decades, while an interest in TCM has been growing among Western clinicians, progress has been made in the comprehension of pathogenic mechanisms of skin disorders, and the communication between Western and Eastern medicines has become more and more intensive. In this paper, the authors discuss TCM remedies used in the treatment of autoimmune bullous disorders (pemphigus and bullous pemphigoid) and lichen planus. Future studies on the active components of the TCM will certainly shed new light on the still obscure aspects of some dermatologic diseases.
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Doenças Autoimunes/terapia , Medicamentos de Ervas Chinesas/uso terapêutico , Líquen Plano/terapia , Medicina Tradicional Chinesa , Dermatopatias Vesiculobolhosas/terapia , HumanosRESUMO
Traditional Chinese medicine (TCM) is increasingly being used in the Western world particularly in specialty areas such as gynecology, pediatrics, nutrition, and dermatology. TCM is an alternative method of therapy that proposes to treat symptoms that Western medicine is unable to manage by treating the underlying causes of disease. The authors provide a general overview of TCM remedies used in the treatment of various dermatologic disorders (acne, psoriasis, atopic dermatitis) for dermatologists interested in this unconventional therapeutic approach.
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Acne Vulgar/terapia , Medicina Tradicional Chinesa/métodos , Psoríase/terapia , Dermatopatias/terapia , Acne Vulgar/patologia , Dermatite Atópica/tratamento farmacológico , Medicamentos de Ervas Chinesas/uso terapêutico , Humanos , Psoríase/patologia , Dermatopatias/patologiaRESUMO
Idiopathic facial aseptic granuloma is a chronic, benign, and painless facial nodule occurring exclusively in childhood. Its pathogenesis is unclear, although some interesting hypotheses have been advanced. On the basis of the relationship existing between this disease and recurrent chalazions and conjunctivitis, we hypothesize that it could be considered to be a possible marker of childhood rosacea.
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Dermatoses Faciais/diagnóstico por imagem , Dermatoses Faciais/etiologia , Granuloma/complicações , Granuloma/diagnóstico por imagem , Rosácea/complicações , Rosácea/diagnóstico por imagem , Idade de Início , Pré-Escolar , Feminino , Humanos , UltrassonografiaRESUMO
Oral Candidiasis (OC) is an opportunistic fungal infection of the oral cavity, frequently reported under local and systemic predisposing circumstances. While the recurrence of OC HIV-infected subjects has been well described and reported, the association between oral candidiasis and the SARS-CoV-2 infection is a recent finding that still is worthy of further study. The present paper focuses on this novel association, reporting the incidence and prevalence of OC occurring during and after COVID-19 and the possible etiopathogenic mechanisms underlying the onset of OC in COVID-19 subjects. The work found that the immune inflammatory hypo reactions and immunosuppression found in children and adults with COVID-19 could favor the proliferation colonization of Candida species and the following infection. At the same time, poor oral hygiene and iatrogenic causes seem to be the main risk factors.
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The skin serves as the first barrier against pathogen attacks, thanks to its multifunctional microbial community. Malassezia furfur is a commensal organism of normal cutaneous microflora but is also a cause of skin diseases. It acts on different cell pattern recognition receptors (TLRs, AhR, NLRP3 inflammasome) leading to cellular damage, barrier impairment, and inflammatory cytokines production. Lactobacillus spp. Is an endogenous inhabitant of healthy skin, and studies have proven its beneficial role in wound healing, skin inflammation, and protection against pathogen infections. The aim of our study is to demonstrate the ability of live Lactiplantibacillus plantarum to interfere with the harmful effects of the yeast on human keratinocytes (HaCat) in vitro. To enable this, the cells were treated with M. furfur, either alone or in the presence of L. plantarum. To study the inflammasome activation, cells require a stimulus triggering inflammation (LPS) before M. furfur infection, with or without L. plantarum. L. plantarum effectively counteracts all the harmful strategies of yeast, reducing the phospholipase activity, accelerating wound repair, restoring barrier integrity, reducing AhR and NLRP3 inflammasome activation, and, consequently, releasing inflammatory cytokines. Although lactobacilli have a long history of use in fermented foods, it can be speculated that they can also have health-promoting activities when topically applied.
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Oral candidiasis (OC) is an opportunistic fungal infection of the oral mucosae, sustained by Candida albicans or other non-albican Candida species (NAC), usually eradicated by conventional antifungals of the classes of azoles, polyenes, or derivative from echinocandins. OC usually occurs under predisposing local or systemic factors. C. lusitaniae is an opportunistic strain that is rarely responsible for human infection and occurs mainly in severe immunocompromised states. The present work reported an unconventional case of OC in an otherwise healthy immunocompetent woman sustained by C. lusitaniae and a multi-resistant strain of C. albicans.
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In addition to the direct impact of the SARS-CoV-2 infection, the COVID-19 pandemic reports multiple effects on people's health and psycho-physical well-being. In the dental field, oral hygiene sessions, regular dental check-ups, and aerosol-generating procedures were commonly postponed, thus resulting in repercussions on oral health also favored by the changing eating and oral hygiene habits during the multiple lockdowns. Furthermore, dental settings and practices were generally perceived as at high risk for SARS-CoV-2 transmission, thus unsafe, and by general and pediatric dentists themselves. Last, the consequences of stress related to deprivation of social life and playful activities should not be underestimated in children, exposing them to the deleterious effects of bad oral habits, with repercussions on the balanced growth and development of the stomatognathic system. The present work intends to analyze the medium-term and long-term impact of COVID-19 on pediatric oral and dental care provision, reviewing pediatric dentistry practice and oral and dental needs of pedodontics patients during the first peak and the various waves of the COVID-19 pandemic, and lessons learned.
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This paper introduces a dynamic clustering methodology based on multi-valued descriptors of dermoscopic images. The main idea is to support medical diagnosis to decide if pigmented skin lesions belonging to an uncertain set are nearer to malignant melanoma or to benign nevi. Melanoma is the most deadly skin cancer, and early diagnosis is a current challenge for clinicians. Most data analysis algorithms for skin lesions discrimination focus on segmentation and extraction of features of categorical or numerical type. As an alternative approach, this paper introduces two new concepts: first, it considers multi-valued data that scalar variables not only describe but also intervals or histogram variables; second, it introduces a dynamic clustering method based on Wasserstein distance to compare multi-valued data. The overall strategy of analysis can be summarized into the following steps: first, a segmentation of dermoscopic images allows to identify a set of multi-valued descriptors; second, we performed a discriminant analysis on a set of images where there is an a priori classification so that it is possible to detect which features discriminate the benign and malignant lesions; and third, we performed the proposed dynamic clustering method on the uncertain cases, which need to be associated to one of the two previously mentioned groups. Results based on clinical data show that the grading of specific descriptors associated to dermoscopic characteristics provides a novel way to characterize uncertain lesions that can help the dermatologist's diagnosis.
Assuntos
Algoritmos , Dermoscopia/métodos , Melanoma/patologia , Neoplasias Cutâneas/patologia , Dermoscopia/normas , Análise Discriminante , Humanos , Melanoma/diagnóstico , Neoplasias Cutâneas/diagnóstico , Melanoma Maligno CutâneoRESUMO
The recruitment of circulating endothelial progenitor cells (EPCs) might have a beneficial effect on the clinical course of several diseases. Endothelial damage and detachment of endothelial cells are known to occur in infection, tissue ischemia, and sepsis. These detrimental effects in EPCs are unknown. Here we elucidated whether human EPCs internalize Bartonella henselae constituting a circulating niche of the pathogen. B. henselae invades EPCs as shown by gentamicin protection assays and transmission electron microscopy (TEM). Dil-Ac-LDL/lectin double immunostaining and fluorescence-activated cell sorting (FACS) analysis of EPCs revealed EPC bioactivity after infection with B. henselae. Nitric oxide (NO) and its precursor l-arginine (l-arg) exert a plethora of beneficial effects on vascular function and modulation of immune response. Therefore, we tested also the hypothesis that l-arg (1-30 mM) would affect the infection of B. henselae or tumor necrosis factor (TNF) in EPCs. Our data provide evidence that l-arg counteracts detrimental effects induced by TNF or Bartonella infections via NO (confirmed by DETA-NO and L-NMMA experiments) and by modulation of p38 kinase phosphorylation. Microarray analysis indicated several genes involved in immune response were differentially expressed in Bartonella-infected EPCs, whereas these genes returned in steady state when cells were exposed to sustained doses of l-arg. This mechanism may have broad therapeutic applications in tissue ischemia, angiogenesis, immune response, and sepsis.