Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Arch Dermatol Res ; 316(6): 275, 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38796546

RESUMO

PURPOSE: A skin lesion refers to an area of the skin that exhibits anomalous growth or distinctive visual characteristics compared to the surrounding skin. Benign skin lesions are noncancerous and generally pose no threat. These irregular skin growths can vary in appearance. On the other hand, malignant skin lesions correspond to skin cancer, which happens to be the most prevalent form of cancer in the United States. Skin cancer involves the unusual proliferation of skin cells anywhere on the body. The conventional method for detecting skin cancer is relatively more painful. METHODS: This work involves the automated prediction of skin cancer and its types using two stage Convolutional Neural Network (CNN). The first stage of CNN extracts low level features and second stage extracts high level features. Feature selection is done using these two CNN and ABCD (Asymmetry, Border irregularity, Colour variation, and Diameter) technique. The features extracted from the two CNNs are fused with ABCD features and fed into classifiers for the final prediction. The classifiers employed in this work include ensemble learning methods such as gradient boosting and XG boost, as well as machine learning classifiers like decision trees and logistic regression. This methodology is evaluated using the International Skin Imaging Collaboration (ISIC) 2018 and 2019 dataset. RESULTS: As a result, the first stage CNN which is used for creation of new dataset achieved an accuracy of 97.92%. Second stage CNN which is used for feature selection achieved an accuracy of 98.86%. Classification results are obtained for both with and without fusion of features. CONCLUSION: Therefore, two stage prediction model achieved better results with feature fusion.


Assuntos
Melanoma , Redes Neurais de Computação , Neoplasias Cutâneas , Humanos , Melanoma/diagnóstico , Melanoma/patologia , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/patologia , Pele/patologia , Pele/diagnóstico por imagem , Aprendizado de Máquina , Aprendizado Profundo , Interpretação de Imagem Assistida por Computador/métodos , Melanoma Maligno Cutâneo , Dermoscopia/métodos
2.
J Neurosci ; 41(8): 1779-1787, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33380469

RESUMO

Allelic variation in CHRNA3, the gene encoding the α3 nicotinic acetylcholine receptor (nAChR) subunit, increases vulnerability to tobacco dependence and smoking-related diseases, but little is known about the role for α3-containing (α3*) nAChRs in regulating the addiction-related behavioral or physiological actions of nicotine. α3* nAChRs are densely expressed by medial habenula (mHb) neurons, which project almost exclusively to the interpeduncular nucleus (IPn) and are known to regulate nicotine avoidance behaviors. We found that Chrna3tm1.1Hwrt hypomorphic mice, which express constitutively low levels of α3* nAChRs, self-administer greater quantities of nicotine (0.4 mg kg-1 per infusion) than their wild-type littermates. Microinfusion of a lentivirus vector to express a short-hairpin RNA into the mHb or IPn to knock-down Chrna3 transcripts markedly increased nicotine self-administration behavior in rats (0.01-0.18 mg kg-1 per infusion). Using whole-cell recordings, we found that the α3ß4* nAChR-selective antagonist α-conotoxin AuIB almost completely abolished nicotine-evoked currents in mHb neurons. By contrast, the α3ß2* nAChR-selective antagonist α-conotoxin MII only partially attenuated these currents. Finally, micro-infusion of α-conotoxin AuIB (10 µm) but not α-conotoxin MII (10 µm) into the IPn in rats increased nicotine self-administration behavior. Together, these data suggest that α3ß4* nAChRs regulate the stimulatory effects of nicotine on the mHb-IPn circuit and thereby regulate nicotine avoidance behaviors. These findings provide mechanistic insights into how CHRNA3 risk alleles can increase the risk of tobacco dependence and smoking-related diseases in human smokers.SIGNIFICANCE STATEMENT Allelic variation in CHRNA3, which encodes the α3 nicotinic acetylcholine receptor (nAChR) subunit gene, increases risk of tobacco dependence but underlying mechanisms are unclear. We report that Chrna3 hypomorphic mice consume greater quantities of nicotine than wild-type mice and that knock-down of Chrna3 gene transcripts in the habenula or interpeduncular nucleus (IPn) increases nicotine intake in rats. α-Conotoxin AuIB, a potent antagonist of the α3ß4 nAChR subtype, reduced the stimulatory effects of nicotine on habenular neurons, and its infusion into the IPn increased nicotine intake in rats. These data suggest that α3ß4 nAChRs in the habenula-IPn circuit regulate the motivational properties of nicotine.


Assuntos
Habenula/metabolismo , Núcleo Interpeduncular/metabolismo , Receptores Nicotínicos/metabolismo , Tabagismo/metabolismo , Animais , Feminino , Predisposição Genética para Doença/genética , Variação Genética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Ratos , Ratos Wistar , Receptores Nicotínicos/genética , Tabagismo/genética
3.
Nicotine Tob Res ; 22(8): 1364-1373, 2020 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-32396625

RESUMO

INTRODUCTION: During adolescence, exposure to nicotine or cannabis independently induces effects on neuromaturation and later cognitive function. However, the potential effect of both drugs under co-use conditions has become of increasing concern given the prevalence of e-cigarettes, legalization of cannabis, and availability of synthetic "spice" cannabinoid agonists. AIMS AND METHODS: The current studies investigated the effects of exposure to a cannabinoid receptor agonist (WIN55,212-2) and/or nicotine over a discrete time period in mid-adolescence on later intravenous nicotine self-administration in adult male and female mice. We further examined whether cannabinoid agonist administration in adulthood would alter nicotine reinforcement, with either acute or chronic pairing across 7 days. RESULTS: We found that adult males exhibited increased nicotine self-administration at a lower, rewarding nicotine dose following adolescent cannabinoid exposure, either alone or with nicotine coadministration. In contrast, adult females demonstrated an opposing effect in which adolescent cannabinoid and nicotine coexposure resulted in decreased nicotine intake compared with the nicotine only and control groups. Furthermore, after maintaining nicotine self-administration across sessions, pretreatment with a low dose of the cannabinoid agonist decreased nicotine intake in both male and female control mice, and this lowering effect was evidenced after both acute and chronic treatment. However, the cannabinoid agonist was ineffective in altering nicotine intake in mice previously exposed to nicotine, cannabinoid agonist, or both during adolescence. CONCLUSIONS: These data provide evidence that adolescent drug exposure can alter later nicotine reinforcement in a sex-specific manner and can further modulate the effectiveness of interventions in reducing nicotine intake during adulthood. IMPLICATIONS: These studies demonstrate a significant impact of nicotine, cannabinoids, or coexposure on developmental processes during adolescence. Differential effects were observed within each sex, with opposing results found for cannabinoid exposure on nicotine intake in males and females. Intriguingly, we also evidenced resistance to the lowering effects of a cannabinoid agonist on nicotine intake in adulthood based on adolescent drug exposure. Thus, these findings have important implications for our understanding of the impact of nicotine and cannabinoids (eg, Δ9-tetrahydrocannabinol (THC) and synthetic "spice" cannabinoids) during development, with further implications for the effectiveness of therapeutic interventions based on prior drug exposure in youth.


Assuntos
Canabinoides/administração & dosagem , Sistemas Eletrônicos de Liberação de Nicotina/estatística & dados numéricos , Nicotina/administração & dosagem , Reforço Psicológico , Recompensa , Autoadministração/métodos , Adolescente , Adulto , Animais , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL
4.
Anticancer Res ; 40(2): 719-722, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32014913

RESUMO

AIM: A commercially available light emitting diode (LED) that transmitted narrow band ultraviolet B (UVB) radiation was evaluated for its efficacy and efficiency to produce vitamin D3 in human skin. MATERIALS AND METHODS: Human skin samples were obtained from surgical procedures. The LED had peak emission wavelength of 295 nm. Skin samples were exposed to the UVB-LED for varying times and then were analyzed by high-pressure liquid chromatography (HPLC) to determine the vitamin D3 content. RESULTS: There was a statistically significant time- and dose-dependent increase in the percent of 7-dehydrocholesterol that was converted to vitamin D3 in the skin type II samples; 1.3%±0.5, 2.3%±0.6 and 4.5%±1.67 after exposure to 0.75 (11.7 mJ/cm2), 1.5 (23.4 mJ/cm2) and 3 (46.8 mJ/cm2) minimal erythemal doses (MEDs), respectively. CONCLUSION: The UVB-LED was effective and efficient in generating vitamin D3 in human skin, in vitro. The amount of vitamin D3 production increased in a dose-dependent fashion with increased UVB energy. UVB-LEDs can be developed for devices that can efficiently produce vitamin D3 in human skin.


Assuntos
Colecalciferol/biossíntese , Pele/metabolismo , Pele/efeitos da radiação , Raios Ultravioleta , Colecalciferol/metabolismo , Cromatografia Líquida de Alta Pressão , Desidrocolesteróis/metabolismo , Relação Dose-Resposta à Radiação , Humanos
5.
PLoS One ; 14(1): e0211346, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30703155

RESUMO

Nicotine and cannabis use during adolescence has the potential to induce long lasting changes on affective and cognitive function. Here, we examined whether adolescent exposure to nicotine, the cannabinoid agonist WIN55-212,2 (WIN), or co-exposure to both would alter operant learning, locomotion, and anxiety- and reward-related behaviors in male and female mice during adulthood. Males exposed to a moderate dose of WIN (2 mg/kg) or co-exposed to nicotine and the moderate dose of WIN exhibited decreased anxiety-associated behaviors and increased cognitive flexibility, but did not differ in operant learning or generalized locomotion. In contrast, differences were not found among the females in these measures at the moderate WIN dose or in both sexes with exposure to a low WIN dose (0.2 mg/kg). Furthermore, a sex-dependent dissociative effect was found in natural reward consumption. Males exposed to the moderate dose of WIN or co-exposed to nicotine and the moderate dose of WIN demonstrated increased sucrose consumption. In contrast, females exposed to the moderate dose of WIN exhibited a decrease in sucrose consumption, which was ameliorated with co-administration of nicotine. Together, these novel findings demonstrate that adolescent exposure to cannabinoids in the presence or absence of nicotine results in altered affective and reward-related behaviors during adulthood.


Assuntos
Ansiedade/tratamento farmacológico , Benzoxazinas/efeitos adversos , Morfolinas/efeitos adversos , Naftalenos/efeitos adversos , Nicotina/efeitos adversos , Animais , Condicionamento Operante/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Humanos , Locomoção/efeitos dos fármacos , Masculino , Camundongos , Recompensa , Caracteres Sexuais , Sacarose/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA