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1.
Skin Health Dis ; 1(2): e19, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35664971

RESUMO

Background: Many classifiers have been developed that can distinguish different types of skin lesions (e.g., benign nevi, melanoma) with varying degrees of success.1-5 However, even successfully trained classifiers may perform poorly on images that include artefacts. While problems created by hair and ink markings have been published, quantitative measurements of blur, colour and lighting variations on classification accuracy has not yet been reported to our knowledge. Objectives: We created a system that measures the impact of various artefacts on machine learning accuracy. Our objectives were to (1) quantitatively identify the most egregious artefacts and (2) demonstrate how to assess a classification algorithm's accuracy when input images include artefacts. Methods: We injected artefacts into dermatologic images using techniques that could be controlled with a single variable. This allows us to quantitatively evaluate the impact on the accuracy. We trained two convolutional neural networks on two different binary classification tasks and measured the impact on dermoscopy images over a range of parameter values. The area under the curve and specificity-at-a-given-sensitivity values were measured for each artefact induced at each parameter. Results: General blur had the strongest negative effect on the melanoma versus other task. Conversely, shifting the hue towards blue had a more pronounced effect on the suspicious versus follow task. Conclusions: Classifiers should either mitigate artefacts or detect them. Images should be excluded from diagnosis/recommendation when artefacts are present in amounts outside the machine perceived quality range. Failure to do so will reduce accuracy and impede approval from regulatory agencies.

2.
Oncogene ; 30(3): 265-74, 2011 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-20838381

RESUMO

Mutations or deletions in the cyclin-dependent kinase inhibitor p16(INK4A) are associated with multiple cancer types, but are more commonly found in melanoma tumors and associated with familial melanoma predisposition. Although p16 is thought to function as a tumor suppressor by negatively regulating the cell cycle, it remains unclear why the genetic compromise of p16 predisposes to melanoma over other cancers. Here we describe a novel role for p16 in regulating oxidative stress in several cell types, including melanocytes. Expression of p16 was rapidly upregulated following ultraviolet-irradiation and in response to H2O2-induced oxidative stress in a p38 stress-activated protein kinase-dependent manner. Knockdown of p16 using small interfering RNA increased intracellular reactive oxygen species (ROS) and oxidative (8-oxoguanine) DNA damage, which was further enhanced by H2O2 treatment. Elevated ROS levels were also observed in p16-depleted human keratinocytes and in whole skin and dermal fibroblasts from Cdkn2a-deficient mice. Aberrant ROS and p38 signaling in Cdkn2a-deficient fibroblasts was normalized by expression of exogenous p16. The effect of p16 depletion on ROS was not recapitulated by the knockdown of retinoblastoma protein (Rb) and did not require Rb. Finally, p16-mediated suppression of ROS could not be attributed to the potential effects of p16 on cell cycle phase. These findings suggest a potential alternate Rb-independent tumor-suppressor function of p16 as an endogenous regulator of carcinogenic intracellular oxidative stress. Compared with keratinocytes and fibroblasts, we also found increased susceptibility of melanocytes to oxidative stress in the context of p16 depletion, which may explain why the compromise of p16 predisposes to melanoma over other cancers.


Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/fisiologia , Estresse Oxidativo/fisiologia , Animais , Inibidor p16 de Quinase Dependente de Ciclina/genética , Humanos , Peróxido de Hidrogênio/farmacologia , Camundongos , Camundongos Knockout , RNA Interferente Pequeno , Espécies Reativas de Oxigênio/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
3.
G Ital Dermatol Venereol ; 145(1): 37-45, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20197744

RESUMO

About 5-10% of human cutaneous malignant melanoma is hereditary and known to involve rare germline mutations in highly penetrant, autosomal dominant genes. These genes are important in cell cycle control but are not responsible for all familial cases of melanoma. Epidemiologic studies have linked specific phenotypic traits including fair skin, light-colored eyes, and poor tanning ability to melanoma risks. The ability to visually discern and define pigmentary phenotypes in humans and in animal models has permitted elucidation of many genes involved in pigmentation and melanin biosynthesis. Additional genetic epidemiological studies have recently identified a subset of these pigmentation genes that are associated with risk for melanoma and other cutaneous malignancies as well as photosensitivity. Genome-wide association studies (GWAS) have unveiled single nucleotide polymorphisms (SNPs) or genetic variants in MC1R, TPCN2, ASIP, KITLG, NCKX5, TYR, IRF4, OCA2, and TYRP1 pigmentation genes. These findings emphasize the contribution of pigmentation pathways to melanoma predisposition and tumorigenesis through gene-environment interactions. Since pigmentation genes in the melanin synthesis pathway also confer risk for cutaneous malignancy, a better understanding of the operative molecular mechanisms involved in this relationship has the potential to impact individual risk assessment for cutaneous malignant melanoma in the future. This paper is an overview of our current understanding of pigmentation gene modifications that have been associated with melanoma risk and how these genes can enrich clinical management, prevention, and early detection of malignant melanoma.


Assuntos
Melanoma/genética , Neoplasias Cutâneas/genética , Pigmentação da Pele/genética , Raios Ultravioleta/efeitos adversos , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Humanos , Melanoma/etiologia , Mutação , Fenótipo , Polimorfismo de Nucleotídeo Único , Medição de Risco , Neoplasias Cutâneas/etiologia
4.
Oncogene ; 25(52): 6968-74, 2006 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-16702945

RESUMO

The inhibitor of apoptosis gene family member Survivin is highly expressed in most tumors, and appears to be a promising target for cancer therapy. Although a variety of Survivin antagonists have been shown to induce apoptosis in malignant cells, the potential utility of these agents is limited by inefficient delivery and cell impermeability. We generated recombinant fusion proteins containing the TAT protein transduction domain and either wild-type Survivin (TAT-Surv-WT) or a dominant-negative mutant (TAT-Surv-T34A). The TAT-Surv proteins were purified by sequential affinity and ion-exchange chromatography, and at 30 nM concentration demonstrated rapid entry into cells at 30 min. Whereas TAT-Surv-WT had minimal effect on YUSAC2 or WM793 melanoma cells, TAT-Surv-T34A induced cell detachment, DNA fragmentation, caspase-3 activation and mitochondrial release of apoptosis-inducing factor at low microM concentrations. Intraperitoneal (i.p.) injection of mice bearing subcutaneous YUSAC2 xenografts with TAT-Surv-T34A (10 mg/kg) was associated with rapid tumor accumulation at 1 h, and increased tumor cell apoptosis and aberrant nuclei formation in situ. Repeated i.p. injection of TAT-Surv-T34A resulted in a 40-50% reduction in growth and mass of established tumors, compared to those similarly injected with saline buffer or TAT-Surv-WT. These studies demonstrate the feasibility of systemic tumor treatment using a cell-permeable Survivin antagonist.


Assuntos
Apoptose/fisiologia , Produtos do Gene tat/uso terapêutico , Melanoma/patologia , Melanoma/terapia , Proteínas Associadas aos Microtúbulos/antagonistas & inibidores , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas Recombinantes de Fusão/uso terapêutico , Animais , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Proliferação de Células/efeitos dos fármacos , Eletroforese em Gel de Poliacrilamida , Citometria de Fluxo , Humanos , Proteínas Inibidoras de Apoptose , Camundongos , Neoplasias Experimentais/terapia , Survivina , Transdução Genética
5.
Radiat Res ; 161(6): 739-45, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15161345

RESUMO

In this study, we examined effects of low-dose ionizing radiation on organ cultured human foreskin and, in particular, on the epidermis. Diagnostic, therapeutic, natural environmental and incidental exposures to moderate to low doses of radiation are inevitable and, although information on cultured cells continues to accumulate, little is known about the effects of low-dose radiation on human tissues. Our hypothesis is that ex vivo organ cultured foreskin is a simple and reliable model to study the biochemical effects of low-dose radiation exposure on skin. A model such as this will aid in the identification and quantification of low-dose radiation-induced changes in proteins in human skin and may be useful in the development of a precise, non-invasive, and reliable assay of exposure. In this work, several aspects of skin responses to culture conditions and radiation were examined. The responses of epidermal TP53 from organ cultured skin irradiated in medium with and without serum were found to be similar. TP53 levels in organ cultured neonatal foreskin epidermis were then examined for baseline TP53 expression. After an initial increase at 4 h, the TP53 D01 signal returned to low steady-state levels for at least 72 h. Irradiated skin samples from different individuals revealed variations in the TP53 D01 signal. The dose and temporal response of dermis and epidermis to radiation were examined by Western blotting from 0 to 24 h after exposure. After irradiation and incubation, the epidermis was removed and assayed by Western blotting and was found to have increases in the TP53 D01 epitope and the TP53 phosphoserine 15 (TP53-S15p) epitope that reached a maximum at about 3 h. In the epidermis, doses of 1-5 cGy of radiation were detectable with the TP53 D01, and CDKN1A antibodies and doses greater than 10 cGy were detectable with the TP53-S15p antibody. When the dermis was compared to epidermis, it was found that dermis had a smaller response to radiation and more phosphorylated TP53.


Assuntos
Ciclinas/metabolismo , Derme/metabolismo , Derme/efeitos da radiação , Pele/metabolismo , Pele/efeitos da radiação , Proteína Supressora de Tumor p53/metabolismo , Técnicas de Cultura , Inibidor de Quinase Dependente de Ciclina p21 , Relação Dose-Resposta à Radiação , Epiderme/metabolismo , Epiderme/efeitos da radiação , Humanos , Recém-Nascido , Masculino , Pênis/metabolismo , Pênis/efeitos da radiação , Fosforilação/efeitos da radiação , Doses de Radiação , Serina/metabolismo
6.
Mod Pathol ; 14(2): 116-28, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11235903

RESUMO

Few human tumors are collected such that RNA is preserved for molecular analysis. Completion of the Human Genome Project will soon result in the identification of more than 100,000 new genes. Consequently, increasing attention is being diverted to identifying the function of these newly described genes. Here we describe a multidisciplinary tumor bank procurement protocol that preserves both the integrity of tissue for pathologic diagnosis, and the RNA for molecular analyses. Freshly excised normal skin was obtained from five patients undergoing wound reconstruction following Mohs micrographic surgery for cutaneous neoplasia. Tissues treated for 24 hours with RNAlater were compared histologically and immunohistochemically to tissues not treated with RNAlater. Immunohistochemical stains studied included: CD45, CEA, cytokeratin AE1/3, vimentin, S-100, and CD34 on formalin-fixed, paraffin embedded tissue and CD45 staining of frozen tissue. Slides were blinded and evaluated independently by three pathologists. The histologic and immunohistochemical parameters of tissue stored in RNAlater were indistinguishable from tissue processed in standard fashion with the exception of S-100 stain which failed to identify melanocytes or Langerhan's cells within the epidermis in any of the RNAlater-treated tissues. Interestingly, nerve trunks within the dermis stained appropriately for S-100. Multiple non-cutaneous autopsy tissues were treated with RNAlater, formalin, liquid nitrogen (LN2), and TRIzol Reagent. The pathologists were unable to distinguish between tissues treated with RNAlater, formalin, or frozen in LN2, but could easily distinguish tissues treated with TRIzol Reagent because of extensive cytolysis. RNA was isolated from a portion of the tissue treated with RNAlater and used for molecular studies including Northern blotting and microarray analysis. RNA was adequate for Northern blot analysis and mRNA purified from RNAlater-treated tissues consistently provided excellent templates for reverse transcription and subsequent microarray analysis. We conclude that tissues treated with RNAlater before routine processing are indistinguishable histologically and immunohistochemically from tissues processed in routine fashion and that the RNA isolated from these tissues is of high quality and can be used for molecular studies. Based on this study, we developed a multidisciplinary tumor bank procurement protocol in which fresh tissue from resection specimens are routinely stored in RNAlater at the time of preliminary dissection. Thus, precious human tissue can be utilized for functional genomic studies without compromising the tissue's diagnostic and prognostic qualities.


Assuntos
Estabilidade de RNA , Bancos de Tecidos , Preservação de Tecido/métodos , Idoso , Idoso de 80 Anos ou mais , Carcinoma/genética , Carcinoma/patologia , Exocitose , Feminino , Genômica , Guias como Assunto , Projeto Genoma Humano , Humanos , Técnicas Imunoenzimáticas , Masculino , Melanoma/genética , Melanoma/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Patologia Cirúrgica/métodos , RNA/isolamento & purificação , Pele/química , Pele/citologia , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia
7.
J Virol ; 74(18): 8700-8, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10954571

RESUMO

A cottontail rabbit papillomavirus (CRPV) E6 DNA vaccine that induces significant protection against CRPV challenge was used in a superior vaccination regimen in which the cutaneous sites of vaccination were primed with an expression vector encoding granulocyte-macrophage colony-stimulating factor (GM-CSF), a cytokine that induces differentiation and local recruitment of professional antigen-presenting cells. This treatment induced a massive influx of major histocompatibility complex class II-positive cells. In a vaccination-challenge experiment, rabbit groups were treated by E6 DNA vaccination, GM-CSF DNA inoculation, or a combination of both treatments. After two immunizations, rabbits were challenged with CRPV at low, moderate, and high stringencies and monitored for papilloma formation. As expected, all clinical outcomes were monotonically related to the stringency of the viral challenge. The results demonstrate that GM-CSF priming greatly augmented the effects of CRPV E6 vaccination. First, challenge sites in control rabbits (at the moderate challenge stringency) had a 0% probability of remaining disease free, versus a 50% probability in E6-vaccinated rabbits, and whereas GM-CSF alone had no effect, the interaction between GM-CSF priming and E6 vaccination increased disease-free survival to 67%. Second, the incubation period before papilloma onset was lengthened by E6 DNA vaccination alone or to some extent by GM-CSF DNA inoculation alone, and the combination of treatments induced additive effects. Third, the rate of papilloma growth was reduced by E6 vaccination and, to a lesser extent, by GM-CSF treatment. In addition, the interaction between the E6 and GM-CSF treatments was synergistic and yielded more than a 99% reduction in papilloma volume. Finally, regression occurred among the papillomas that formed in rabbits treated with the E6 vaccine and/or with GM-CSF, with the highest regression frequency occurring in rabbits that received the combination treatment.


Assuntos
Papillomavirus de Coelho Cottontail/genética , Técnicas de Transferência de Genes , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Papiloma/prevenção & controle , Infecções por Papillomavirus/prevenção & controle , Infecções Tumorais por Vírus/prevenção & controle , Vacinas de DNA/metabolismo , Vacinas Virais/metabolismo , Animais , Biópsia , Papillomavirus de Coelho Cottontail/metabolismo , DNA Viral/genética , DNA Viral/metabolismo , Modelos Animais de Doenças , Intervalo Livre de Doença , Vetores Genéticos , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Imuno-Histoquímica , Hibridização In Situ , Papiloma/patologia , Papiloma/virologia , Infecções por Papillomavirus/patologia , Infecções por Papillomavirus/virologia , Coelhos , Infecções Tumorais por Vírus/patologia , Infecções Tumorais por Vírus/virologia , Vacinas de DNA/genética , Vacinas Virais/genética
8.
Arch Dermatol ; 135(8): 961-5, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10456346

RESUMO

BACKGROUND: Few studies have been done of bone densities in humans receiving retinoids, despite a substantial amount of literature concerning retinoid-induced osteoporosis in animals. We prospectively measured bone density and calcium metabolism in young men (aged 17-25 years) receiving oral isotretinoin for cystic acne and in a group of healthy volunteers (aged 19-26 years). OBSERVATIONS: Compared with that in healthy control subjects, mean bone density was lower at all sites (spine, femoral neck, and Ward triangle) and was considerably more variable at the spine in young men with cystic acne even before treatment. Bone density at the Ward triangle decreased a mean of 4.4% (P = .03) after 6 months of isotretinoin use (1 mg/kg of body weight). Four patients showed decreased density of more than 9% at the Ward triangle. The difference between the mean change in bone density in the patient group and in the control group was significant at the Ward triangle (P = .04) but not at the other sites. Measurements of calcium metabolism did not change over time in either group. CONCLUSIONS: A loss of bone density occurring in the absence of measurable alterations of calcium metabolism is likely to be a direct effect of retinoids on bone. Further study of retinoid-induced osteoporosis in humans and of bone density in patients with cystic acne is needed.


Assuntos
Acne Vulgar/tratamento farmacológico , Densidade Óssea/efeitos dos fármacos , Fármacos Dermatológicos/farmacologia , Isotretinoína/farmacologia , Acne Vulgar/patologia , Adolescente , Adulto , Fármacos Dermatológicos/uso terapêutico , Humanos , Isotretinoína/uso terapêutico , Masculino
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