Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 10.953
Filtrar
1.
Anticancer Res ; 40(11): 6505-6511, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33109590

RESUMO

BACKGROUND/AIM: This study aimed to investigate the bolus practice among Italian radiation oncologists. PATIENTS AND METHODS: In 2018, a survey on bolus application was sent to all members of the Italian Association of Radiotherapy and Clinical Oncology. RESULTS: The survey was joined by 102 radiation oncologists. Not all respondents answered to every question. A 69.5% of 82 respondents used bolus in case of skin infiltration and 52 of 68 respondents (76.5%) applied it every day. Skin was included as part of chest wall Clinical Target Volume both in the absence or the presence of breast reconstruction. Five mm bolus was the most used. 3D Conformal radiotherapy was the most used technique, in 73.5% of cases. Acute RTOG G2-G3 skin toxicity was recorded by 93.9% physicians. CONCLUSION: There was heterogeneity in the use of bolus, though an agreement was found in some topics. The achievement of a National Consensus may represent an interesting future goal.


Assuntos
Neoplasias da Mama/epidemiologia , Neoplasias da Mama/radioterapia , Radioterapia Adjuvante/métodos , Pele/efeitos da radiação , Idoso , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Terapia Combinada , Relação Dose-Resposta à Radiação , Feminino , Humanos , Itália/epidemiologia , Mamoplastia , Mastectomia , Oncologia/tendências , Pessoa de Meia-Idade , Padrões de Prática Médica , Radio-Oncologistas , Radioterapia Conformacional , Pele/patologia , Parede Torácica/patologia , Parede Torácica/efeitos da radiação
2.
Adv Exp Med Biol ; 1268: 257-283, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32918223

RESUMO

Nonmelanoma skin cancers including basal and squamous cell carcinomas (SCC and BCC) represent a significant clinical problem due to their relatively high incidence, imposing an economic burden to healthcare systems around the world. It is accepted that ultraviolet radiation (UVR: λ = 290-400 nm) plays a crucial role in the initiation and promotion of BCC and SCC with UVB (λ = 290-320 nm) having a central role in this process. On the other hand, UVB is required for vitamin D3 (D3) production in the skin, which supplies >90% of the body's requirement for this prohormone. Prolonged exposure to UVB can also generate tachysterol and lumisterol. Vitamin D3 itself and its canonical (1,25(OH)2D3) and noncanonical (CYP11A1-intitated) D3 hydroxyderivatives show photoprotective functions in the skin. These include regulation of keratinocyte proliferation and differentiation, induction of anti-oxidative responses, inhibition of DNA damage and induction of DNA repair mechanisms, and anti-inflammatory activities. Studies in animals have demonstrated that D3 hydroxyderivatives can attenuate UVB or chemically induced epidermal cancerogenesis and inhibit growth of SCC and BCC. Genomic and non-genomic mechanisms of action have been suggested. In addition, vitamin D3 itself inhibits hedgehog signaling pathways which have been implicated in many cancers. Silencing of the vitamin D receptor leads to increased propensity to develop UVB or chemically induced epidermal cancers. Other targets for vitamin D compounds include 1,25D3-MARRS, retinoic orphan receptors α and γ, aryl hydrocarbon receptor, and Wnt signaling. Most recently, photoprotective effects of lumisterol hydroxyderivatives have been identified. Clinical trials demonstrated a beneficial role of vitamin D compounds in the treatment of actinic keratosis. In summary, recent advances in vitamin D biology and pharmacology open new exciting opportunities in chemoprevention and treatment of skin cancers.


Assuntos
Neoplasias Cutâneas/etiologia , Neoplasias Cutâneas/prevenção & controle , Vitamina D/química , Animais , Progressão da Doença , Humanos , Receptores de Calcitriol/metabolismo , Pele/efeitos dos fármacos , Pele/metabolismo , Pele/efeitos da radiação , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Raios Ultravioleta/efeitos adversos , Vitamina D/metabolismo , Vitamina D/farmacologia , Vitaminas/química , Vitaminas/metabolismo , Vitaminas/farmacologia
3.
Adv Exp Med Biol ; 1268: 387-405, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32918230

RESUMO

Exposure to sunlight is a major source of vitamin D for most people. Yet public health advice has focused overwhelmingly on avoiding exposure of unprotected skin because of the risks of erythema and skin cancer. Given that there are also health risks associated with low vitamin D status, we explore the possibilities of achieving a range of targets associated with vitamin D and the accompanying erythema risk. We have calculated the exposure required to gain a number of proposed oral-equivalent doses of vitamin D, as functions of latitude, season, skin type and skin area exposed, together with the associated risk of erythema, expressed in minimum erythema doses. The model results show that a recommended daily intake of 400 IU is readily achievable through casual sun exposure in the midday lunch hour, with no risk of erythema, for all latitudes some of the year, and for all the year at some (low) latitudes. We also show that such daily, sub-erythemal doses at lunchtime during the summer months is sufficient to avoid winter-time vitamin D deficiency for the UK all-weather climate, provided that lower arms and legs are exposed in the warmer months. At the higher proposed vitamin D dose of 1000 IU, lunchtime sun exposure is still a viable route to the vitamin but requires the commitment to expose greater areas of skin and is effective for a shorter period of the year. The highest vitamin D requirement considered was 4000 IU per day. For much of the globe and much of the year, this is not achievable in a lunchtime hour and where it is possible large areas of skin must be exposed to prevent erythema. When the only variable considered was skin type, latitudinal and seasonal limits on adequate vitamin D production were more restrictive for skin type 5 than skin type 2.


Assuntos
Eritema/etiologia , Pele/metabolismo , Pele/efeitos da radiação , Raios Ultravioleta/efeitos adversos , Vitamina D/biossíntese , Humanos , Medição de Risco , Pele/patologia , Deficiência de Vitamina D/prevenção & controle
4.
Clin Dermatol ; 38(4): 485-488, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32972607

RESUMO

Many factors affect the health and physiology of human skin, with some of them arising from outer space. This contribution explores four celestial influences on the skin: (1) the sun's ultraviolet light, which has both beneficial and deleterious dermatologic effects, (2) meteorite injuries, (3) possible lunar effects on the body's health, and (4) cosmic radiation as a risk factor for skin cancer and pregnancy-related complications. Some of these extraterrestrial influences on skin health have taken on added significance as human beings increasingly spend more time at higher altitudes in aircraft, spaceships, and space stations.


Assuntos
Radiação Cósmica/efeitos adversos , Neoplasias Cutâneas/etiologia , Pele/lesões , Pele/efeitos da radiação , Luz Solar/efeitos adversos , Raios Ultravioleta/efeitos adversos , Aeronaves , Altitude , Dermatite de Contato/etiologia , Feminino , Humanos , Masculino , Meteoroides , Lua , Gravidez , Complicações na Gravidez/etiologia
5.
Pract Radiat Oncol ; 10(6): e529-e537, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32781247

RESUMO

PURPOSE: Historically, the standard of care for total skin electron beam therapy (TSEBT) delivered 30 to 36 Gy over 5 to 10 weeks. Given the high risk of relapse, a majority of patients require additional treatments. Therefore, attempts to use a shortened course of TSEBT have been investigated. METHODS AND MATERIALS: We conducted a single-institution retrospective review to evaluate disease response, control, and toxicity using a low-dose, hypofractionated course of TSEBT (HTSEBT) in patients with mycosis fungoides. RESULTS: Forty patients received 57 courses of HTSEBT. Median dose (Gy)/fractionation was 12/3, spanning a median time of 2.4 weeks. Overall response rate of patients assessed (n = 54) was 100%. Thirty-one courses (57.4%) resulted in a complete response and 23 courses (42.6%) resulted in a partial response. Cumulative incidence of progressive skin disease at 3 months was 37.2%, at 6 months, 56.9%, and at 1 year, 81.5%. Of the 40 patients treated with a first course of HTSEBT, 31 received subsequent courses of radiotherapy. Cumulative incidence of subsequent treatment was 28.0% at 3 months, 46.8% at 6 months, and 70.0% at 1 year. Patients who underwent repeat courses of HTSEBT continued to have similar treatment responses to repeat courses without increased toxicities. Toxicities from all courses were acceptable with the exception of 1 patient, who experienced grade 4 skin toxicity (moist desquamation requiring hospitalization). CONCLUSIONS: Low-dose HTSEBT provides good palliation in patients with cutaneous T-cell lymphoma with a satisfactory response and toxicity profile. HTSEBT allows therapy to be completed in far fewer treatments. Low-dose HTSEBT is an appropriate treatment option for patients unable to come for daily treatment. HTSEBT provides a way to decrease exposure to other patients and staff during public health emergencies such as the coronavirus disease 2019 (COVID-19) pandemic.


Assuntos
Linfoma Cutâneo de Células T/radioterapia , Pele/efeitos da radiação , Tomografia Computadorizada por Raios X/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Dosagem Radioterapêutica , Estudos Retrospectivos , Pele/patologia
6.
PLoS One ; 15(8): e0235948, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785216

RESUMO

INTRODUCTION: Surgical site infection is one of the most severe complications of surgical treatments. However, the optimal procedure to prevent such infections remains uninvestigated. Ultraviolet radiation C (UVC) with a short wavelength has a high bactericidal effect; however, it is cytotoxic. Nonetheless, given that UVC with a wavelength of 222 nm reaches only the stratum corneum, it does not affect the skin cells. This study aimed to investigate the safety of 222-nm UVC irradiation and to examine its skin sterilization effect in healthy volunteers. METHODS: This trial was conducted on 20 healthy volunteers. The back of the subject was irradiated with 222-nm UVC at 50-500 mJ/cm2, and the induced erythema (redness of skin) was evaluated. Subsequently, the back was irradiated with a maximum amount of UVC not causing erythema, and the skin swabs before and after the irradiation were cultured. The number of colonies formed after 24 hours was measured. In addition, cyclobutene pyrimidine dimer (CPD) as an indicator of DNA damage was measured using skin tissues of the nonirradiated and irradiated regions. RESULTS: All subjects experienced no erythema at all doses. The back of the subject was irradiated at 500 mJ/cm2, and the number of bacterial colonies in the skin swab culture was significantly decreased by 222-nm UVC irradiation. The CPD amount produced in the irradiated region was slightly but significantly higher than that of the non-irradiated region. CONCLUSION: A 222-nm UVC at 500 mJ/cm2 was a safe irradiation dose and possessed bactericidal effects. In the future, 222-nm UVC irradiation is expected to contribute to the prevention of perioperative infection.


Assuntos
Dano ao DNA/efeitos da radiação , Microbiota/efeitos da radiação , Pele/efeitos da radiação , Esterilização/métodos , Raios Ultravioleta/efeitos adversos , Adulto , Dorso , Biópsia , Contagem de Colônia Microbiana , Eritema/diagnóstico , Eritema/etiologia , Voluntários Saudáveis , Humanos , Masculino , Dímeros de Pirimidina/análise , Dímeros de Pirimidina/efeitos da radiação , Pele/microbiologia , Infecção da Ferida Cirúrgica/microbiologia , Infecção da Ferida Cirúrgica/prevenção & controle , Resultado do Tratamento
7.
Surg Clin North Am ; 100(4): 695-705, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32681870

RESUMO

Wound healing is affected by several factors. Preexisting diagnoses may significantly alter, delay, or inhibit normal wound healing. This is most commonly seen with chronic disorders, such as diabetes and renal failure, but also occurs secondary to aging and substance abuse. Less commonly, genetic or inflammatory disorders are the cause of delayed wound healing. In some cases, it is not the illness, but the treatment that can inhibit wound healing. This is seen in patients getting chemotherapy, radiation, steroids, methotrexate, and a host of other medications. Understanding these processes may help treat or avoid wound healing problems.


Assuntos
Falência Renal Crônica/fisiopatologia , Cicatrização/fisiologia , Ferimentos e Lesões/fisiopatologia , Fatores Etários , Antineoplásicos/efeitos adversos , Doenças Autoimunes/complicações , Doenças Autoimunes/fisiopatologia , Doença Crônica , Doenças Genéticas Inatas/complicações , Doenças Genéticas Inatas/fisiopatologia , Humanos , Infecções/complicações , Infecções/fisiopatologia , Falência Renal Crônica/complicações , Transtornos Nutricionais/complicações , Transtornos Nutricionais/fisiopatologia , Lesões por Radiação/complicações , Lesões por Radiação/fisiopatologia , Pele/efeitos da radiação , Dermatopatias/complicações , Dermatopatias/fisiopatologia , Fumar/efeitos adversos , Fumar/fisiopatologia , Ferimentos e Lesões/complicações
8.
Lasers Med Sci ; 35(8): 1681-1687, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32514864

RESUMO

Laser surgery is becoming an increasingly efficacious and customizable treatment modality for the management of pediatric vascular lesions. Proper use requires a thorough understanding of the scientific principles of laser surgery and knowledge of the various lasers available. Moreover, each laser has a multitude of settings that can be employed to properly target the lesion at hand. Each patient will present with unique challenges and variations in the presentation of their vascular lesion. This requires understanding of the most effective laser to use for each lesion and the factors that may alter the desired device settings. Using key search terms, a literature search was conducted on laser surgery for pediatric vascular lesions using PubMed/MEDLINE and Embase for articles published in English or French. Ultimately, 52 articles met our search criteria. The laser indications, limitations, and settings utilized for each type of vascular lesion were compiled for the purposes of this summative review. Laser surgery is an effective and appropriate option for the treatment of certain pediatric vascular lesions. Knowledge of optimal device parameters in every setting is essential to good clinical practice.


Assuntos
Terapia a Laser/instrumentação , Anormalidades da Pele/cirurgia , Pele/irrigação sanguínea , Pele/patologia , Criança , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Pele/efeitos da radiação
9.
Proc Natl Acad Sci U S A ; 117(25): 14412-14420, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32513688

RESUMO

Nucleotide excision repair (NER) removes helix-destabilizing adducts including ultraviolet (UV) lesions, cyclobutane pyrimidine dimers (CPDs), and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs). In comparison with CPDs, 6-4PPs have greater cytotoxicity and more strongly destabilizing properties of the DNA helix. It is generally believed that NER is the only DNA repair pathway that removes the UV lesions as evidenced by the previous data since no repair of UV lesions was detected in NER-deficient skin fibroblasts. Topoisomerase I (TOP1) constantly creates transient single-strand breaks (SSBs) releasing the torsional stress in genomic duplex DNA. Stalled TOP1-SSB complexes can form near DNA lesions including abasic sites and ribonucleotides embedded in chromosomal DNA. Here we show that base excision repair (BER) increases cellular tolerance to UV independently of NER in cancer cells. UV lesions irreversibly trap stable TOP1-SSB complexes near the UV damage in NER-deficient cells, and the resulting SSBs activate BER. Biochemical experiments show that 6-4PPs efficiently induce stable TOP1-SSB complexes, and the long-patch repair synthesis of BER removes 6-4PPs downstream of the SSB. Furthermore, NER-deficient cancer cell lines remove 6-4PPs within 24 h, but not CPDs, and the removal correlates with TOP1 expression. NER-deficient skin fibroblasts weakly express TOP1 and show no detectable repair of 6-4PPs. Remarkably, the ectopic expression of TOP1 in these fibroblasts led them to completely repair 6-4PPs within 24 h. In conclusion, we reveal a DNA repair pathway initiated by TOP1, which significantly contributes to cellular tolerance to UV-induced lesions particularly in malignant cancer cells overexpressing TOP1.


Assuntos
Quebras de DNA de Cadeia Simples/efeitos da radiação , Reparo do DNA , DNA Topoisomerases Tipo I/metabolismo , Raios Ultravioleta/efeitos adversos , Sistemas CRISPR-Cas/genética , DNA Polimerase beta/genética , DNA Polimerase beta/metabolismo , Fibroblastos , Técnicas de Inativação de Genes , Humanos , Células MCF-7 , Cultura Primária de Células , Pele/citologia , Pele/patologia , Pele/efeitos da radiação , Proteína 1 Complementadora Cruzada de Reparo de Raio-X/genética , Proteína 1 Complementadora Cruzada de Reparo de Raio-X/metabolismo , Xeroderma Pigmentoso/etiologia , Xeroderma Pigmentoso/patologia , Proteína de Xeroderma Pigmentoso Grupo A/genética , Proteína de Xeroderma Pigmentoso Grupo A/metabolismo
10.
PLoS One ; 15(5): e0233258, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32442228

RESUMO

The purpose of this paper is to characterize the skin deterministic damage due to the effect of proton beam irradiation in mice occurred during a long-term observational experiment. This study was initially defined to evaluate the insurgence of myelopathy irradiating spinal cords with the distal part of a Spread-out Bragg peak (SOBP). To the best of our knowledge, no study has been conducted highlighting high grades of skin injury at the dose used in this paper. Nevertheless these effects occurred. In this regard, the experimental evidence of significant insurgence of skin injury induced by protons using a SOBP configuration will be shown. Skin damages were classified into six scores (from 0 to 5) according to the severity of the injuries and correlated to ED50 (i.e. the radiation dose at which 50% of animals show a specific score) at 40 days post-irradiation (d.p.i.). The effects of radiation on the overall animal wellbeing have been also monitored and the severity of radiation-induced skin injuries was observed and quantified up to 40 d.p.i.


Assuntos
Terapia com Prótons/efeitos adversos , Lesões por Radiação/patologia , Pele/efeitos da radiação , Animais , Modelos Animais de Doenças , Relação Dose-Resposta à Radiação , Escala de Gravidade do Ferimento , Camundongos
11.
Plast Reconstr Surg ; 145(6): 1037e-1049e, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32459770

RESUMO

BACKGROUND: The major intrinsic cause of facial skin degeneration is age, associated with extrinsic factors such as exposure to sun. Its major pathologic causes are degeneration of the elastin matrix, with loss of oxytalan and elaunin fibers in the subepidermal region, and actinic degeneration of elastin fibers that lose their functional properties in the deep dermis. Therapy using autologous adipose mesenchymal stem cells for regeneration of extracellular matrix in patients with solar elastosis was addressed in qualitative and quantitative analyses of the dermal elastic fiber system and the associated cells. METHODS: Mesenchymal stem cells were obtained from lipoaspirates, expanded in vitro, and introduced into the facial skin of patients submitted after 3 to 4 months to a face-lift operation. In the retrieved skin, immunocytochemical analyses quantified elastic matrix components; cathepsin K; matrix metalloproteinase 12 (macrophage metalloelastase); and the macrophage M2 markers CD68, CD206, and hemeoxygenase-1. RESULTS: A full de novo formation of oxytalan and elaunin fibers was observed in the subepidermal region, with reconstitution of the papillary structure of the dermal-epidermal junction. Elastotic deposits in the deep dermis were substituted by a normal elastin fiber network. The coordinated removal of the pathologic deposits and their substitution by the normal ones was concomitant with activation of cathepsin K and matrix metalloproteinase 12, and with expansion of the M2 macrophage infiltration. CONCLUSION: The full regeneration of solar elastosis was obtained by injection of in vitro expanded autologous adipose mesenchymal stem cells, which are appropriate, competent, and sufficient to elicit the full structural regeneration of the sun-aged skin. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.


Assuntos
Tecido Adiposo/citologia , Transplante de Células-Tronco Mesenquimais/métodos , Cuidados Pré-Operatórios/métodos , Ritidoplastia , Envelhecimento da Pele , Idoso , Biópsia , Brasil , Elastina/análise , Elastina/metabolismo , Matriz Extracelular/metabolismo , Proteínas da Matriz Extracelular/análise , Proteínas da Matriz Extracelular/metabolismo , Face , Feminino , Seguimentos , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Rejuvenescimento , Pele/patologia , Pele/efeitos da radiação , Luz Solar/efeitos adversos , Transplante Autólogo/métodos , Resultado do Tratamento
12.
Nat Commun ; 11(1): 2414, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32415098

RESUMO

Plumage is among the most well-studied components of integumentary colouration. However, plumage conceals most skin in birds, and as a result the presence, evolution and function of skin colour remains unexplored. Here we show, using a database of 2259 species encompassing >99% of bird genera, that melanin-rich, black skin is found in a small but sizeable percentage (~5%) of birds, and that it evolved over 100 times. The spatial distribution of black skin follows Gloger's rule, which states that pigmentation of endothermic animals increases towards the equator. Furthermore, most black-skinned birds inhabit high irradiation regions, and tend to be bald and/or have white feathers. Thus, taken together, our results suggest that melanin-rich, black skin helps to protect birds against ultraviolet irradiation. More generally, our results illustrate that feathered skin colour varies taxonomically, ontogenetically and temporally, providing an additional dimension for avian colour research.


Assuntos
Plumas/fisiologia , Pigmentação da Pele/efeitos da radiação , Pele/efeitos da radiação , Raios Ultravioleta , Animais , Evolução Biológica , Aves , Bases de Dados Factuais , Feminino , Geografia , Masculino , Melaninas/biossíntese , Filogenia , Especificidade da Espécie
13.
Phys Med Biol ; 65(15): 155016, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32442990

RESUMO

Monte Carlo simulations are used to investigate skin dose resulting from chest wall radiotherapy with bolus. A simple model of a female thorax is developed, which includes a 2 mm-thick skin layer. Two representative 6 MV source models are considered: a tangents source model consisting of a parallel opposed pair of medial and lateral fields and subfields, and an arc source model. Tissue equivalent (TE) boluses (thicknesses of 3, 5 and 10 mm) and brass mesh bolus are considered. Skin dose distributions depend on incident photon obliquity: for tangents, radiation is incident more obliquely, resulting in longer path lengths through the bolus and higher skin dose compared to the arc source model in most cases. However, for thicker TE boluses, attenuation of oblique photons becomes apparent. Brass bolus and 3 mm TE bolus result in similar mean skin dose. This relatively simple computational model allows for consideration of different bolus thicknesses, materials and usage schedules based on desired skin dose and choice of either tangents or an arc beam technique. For example, using a 5 mm TE bolus every second treatment would result in mean skin doses of 89% and 85% for tangents and the arc source model, respectively. The hot spot metric D[Formula: see text] would be 103% and 99%, respectively.


Assuntos
Método de Monte Carlo , Imagens de Fantasmas , Doses de Radiação , Planejamento da Radioterapia Assistida por Computador/instrumentação , Pele/efeitos da radiação , Parede Torácica/efeitos da radiação , Feminino , Humanos , Órgãos em Risco/efeitos da radiação , Fótons/efeitos adversos , Fótons/uso terapêutico , Radiometria , Dosagem Radioterapêutica
14.
Lasers Med Sci ; 35(7): 1589-1597, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32277406

RESUMO

Laser therapy has been widely used to treat port-wine stain (PWS) and other cutaneous vascular lesions via selective photothermolysis. High incident laser fluence is always prohibited in clinic to prevent the thermal damage in normal skin tissue, leading to insufficient energy deposition on the target blood vessel and incomplete clearance of PWS lesion. In this study, repeated multipulse laser (RMPL) irradiation was proposed to induce acute thermal damage to target blood vessels with low incident fluence (40 J/cm2 for 1064-nm Nd:YAG laser). The feasibility of the method was investigated using animal models. Repeated multipulse irradiation cycles with 10-min intervals were performed in RMPL. A hamster dorsal skin chamber model with a visualization system was constructed to investigate the instant generation of thermal coagulum and relevant hemostasis by thrombus formation during and after irradiation under 1064 nm Nd:YAG single multipulse laser (SMPL) and RMPL irradiation. The diameter of the target blood vessel and the size of thermal coagula were measured before and after laser irradiation. The reflectance spectra of the dorsal skin were measured by a reflectance spectrometer during RMPL. Stasis thermal coagula that clogged the vessel lumen were generated during SMPL irradiation with low incident fluence. However, there was no acute thermal damage of blood vessels. Reflectance spectra measurement showed that the generation of thermal coagula and subsequent thrombus formation increases blood absorption by more than 10% within the first 10 min after laser irradiation. Acute vessel thermal damage could be induced in the target blood vessel by RMPL with low incident fluence of 40 J/cm2. Compared with our previous SMPL study, nearly 30% reduction in incident laser fluence was achieved by RMPL. Low fluence RMPL may be a promising approach to improve the therapeutic outcome for patients with cutaneous vascular lesions by improving energy deposition on the target blood vessel.


Assuntos
Vasos Sanguíneos/efeitos da radiação , Hemostasia/efeitos da radiação , Lasers de Estado Sólido/uso terapêutico , Pele/irrigação sanguínea , Pele/efeitos da radiação , Temperatura , Animais , Cricetinae , Feminino , Humanos , Camundongos , Mancha Vinho do Porto/cirurgia
15.
Phys Med Biol ; 65(8): 085001, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-32126542

RESUMO

Brachytherapy accelerated partial breast irradiation (APBI) is well tolerated, but reported acute toxicities including moist desquamation rates range from 7% to 39%. Moist desquamation is correlated to long-term skin toxicity and high skin dose is the main risk factor. This study uses radiochromic films for in vivo skin dosimetry of low dose rate (LDR) APBI brachytherapy and prediction of skin toxicity. Patients participating in a clinical trial assessing skin toxicity of LDR seed brachytherapy were included in this study. Following the seed implantation procedure, patients were asked to wear a customized oval shaped radiochromic film on the skin projection of the planned target volume (PTV) for 24 h. Exposed films were collected, and maximum point doses were measured. In addition, maximum doses to a small skin volume (D0.2cc) were calculated on the pre- and post-implant CT-scan. Acute skin toxicities (redness, pigmentation, induration and dermatitis) were scored by the treating physician for 2 months during follow-up visits. Skin dose measurements and acute toxicity were available for 18 consecutive patients. The post-implant calculated maximum skin doses (D0.2cc), 60.8 Gy (SD ± 41.0), were on average 30% higher than those measured in vivo (Dmax-film), 46.6 Gy (SD ± 19.3), but those values were highly significantly correlated (Spearman's rho 0.827, p < 0.001). Also, dermatitis and induration were significantly correlated with higher in vivo measured and post-implant calculated skin dose. Pre-implant dosimetry was not correlated with measured or post-implant skin dose or side effects. Radiochromic films can reliably diagnose excess dose to the skin during the first 24 h and predict skin toxicity, which enables preventative measures. Trial registration: Nederlands Trial Register (www.trialregister.nl), NTR6549, the trial was registered prospectively on 27 June 2017. ABR number: NL56210.078.16.


Assuntos
Braquiterapia/efeitos adversos , Neoplasias da Mama/radioterapia , Dosimetria Fotográfica , Pele/efeitos da radiação , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Dosagem Radioterapêutica , Medição de Risco
16.
Radiat Res ; 193(4): 351-358, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32126188

RESUMO

Millimeter waves (MMW) are broadband frequencies that have recently been used in several applications in wireless communications, medical devices and nonlethal weapons [i.e., the nonlethal weapon, Active Denial Systems, (ADS) operating at 94-95 GHz, CW]. However, little information is available on their potential effects on humans. These radio-frequencies are absorbed and stopped by the first layer of the skin. In this study, we evaluated the effects of 94 GHz on the gene expression of skin cells. Two rat populations consisting of 17 young animals and 14 adults were subjected to chronic long-term 94 GHz MMW exposure. Each group of animals was divided into exposed and sham subgroups. The two independent exposure experiments were conducted for 5 months with rats exposed 3 h per day for 3 days per week to an incident power density of 10 mW/cm2, which corresponded to twice the ICNIRP limit of occupational exposure for humans. At the end of the experiment, skin explants were collected and RNA was extracted. Then, the modifications to the whole gene expression profile were analyzed with a gene expression microarray. Without modification of the animal's temperature, long-term chronic 94 GHz-MMW exposure did not significantly modify the gene expression of the skin on either the young or adult rats.


Assuntos
Regulação da Expressão Gênica/efeitos da radiação , Ondas de Rádio/efeitos adversos , Pele/efeitos da radiação , Tecnologia sem Fio , Animais , Humanos , Ratos , Ratos Pelados/genética , Ratos Pelados/metabolismo , Medição de Risco , Pele/metabolismo , Transcriptoma/efeitos da radiação
17.
Artigo em Inglês | MEDLINE | ID: mdl-32121219

RESUMO

Ultraviolet radiation (UVR) is a ubiquitous exposure which may contribute to decreased folate levels. Skin pigmentation mediates the biological effect of UVR exposure, but its relationship to folate levels is unexamined. Interactions may exist between UVR and pigmentation genes in determining folate status, which may, in turn, impact homocysteine levels, a potential risk factor for multiple chronic diseases. Therefore, independent and interactive influences of environmental UVR and genetic variants related to skin pigmentation (MC1R-rs1805007, IRF4-rs12203592 and HERC2-rs12913832) on folate (red blood cell (RBC) and serum) and homocysteine levels were examined in an elderly Australian cohort (n = 599). Genotypes were assessed by RT/RFLP-PCR, and UVR exposures were assessed as the accumulated erythemal dose rate accumulated over 4 months (4M-EDR). Multivariate analysis found significant negative associations between 4M-EDR and RBC folate (p < 0.001, ß = -0.19), serum folate (p = 0.045, ß = -0.08) and homocysteine levels (p < 0.001, ß = -0.28). Significant associations between MC1R-rs1805007 and serum folate levels (p = 0.020), and IRF4-rs12203592 and homocysteine levels (p = 0.026) occurred but did not remain significant following corrections with confounders. No interactions between 4M-EDR and pigmentation variants in predicting folate/homocysteine levels were found. UVR levels and skin pigmentation-related variants are potential determinants of folate and homocysteine status, although, associations are mixed and complex, with further studies warranted.


Assuntos
Ácido Fólico/sangue , Homocisteína/sangue , Pigmentação da Pele/genética , Pele/efeitos da radiação , Raios Ultravioleta , Idoso , Austrália , Feminino , Genótipo , Humanos , Masculino
18.
PLoS One ; 15(3): e0230175, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32191734

RESUMO

High energy laser, particularly 532 nm, is widely used in defense and medical applications and there is need to address its occupational safety. Thermal and non-thermal effects of 532 nm high energy laser on skin are cause of concern. This study indicates impact of 532 nm laser on rat skin and first of its kind of attempt to understand transcriptional activation of genes as an early response following laser exposure. Skin of experimental rats were exposed to 532 nm radiance at 0.1, 0.25 and 0.50 W/cm2 for 10 sec. Thermographic changes of skin exposed to 532 nm laser exhibited increased Tmax temperature in radiance dependent manner. After thermal imaging, skin of experimental rats was collected 1 h post laser exposure for studying differential gene expression. The skin exposed to lower power density (0.1 W/cm2) did not show significant changes in expression of gene pathways studied. At moderate radiance (0.25 W/cm2), predominantly canonical wnt/B-catenin pathway genes notch1, axin2, ccdn1, wnt5a and redox homeostasis genes; txn1, nqo1 and txnrd1 were expressed. At higher radiance (0.5 W/cm2), significant repression of genes related to wound healing process particularly notch/wnt pathway viz. hes5, wnt1, wn3b with higher expression of dab2 was recorded. The data obtained from these studies would help in drawing safety limits for skin exposure to 532 nm laser. Further, genes expressed at moderate and high level of radiance exposure to skin were distinct and differential and provide new avenue to configure pathway to counteract laser induced delay in tissue injury and hair follicular damage.


Assuntos
Lasers/efeitos adversos , Pele/efeitos da radiação , Fatores de Transcrição/genética , Transcrição Genética/efeitos da radiação , Animais , Expressão Gênica/efeitos da radiação , Masculino , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos da radiação , Ativação Transcricional/efeitos da radiação , Via de Sinalização Wnt/efeitos da radiação , beta Catenina/genética
19.
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
20.
Ecotoxicol Environ Saf ; 192: 110268, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32036099

RESUMO

Present study highlighted the ultramicroscopic (SEM) alterations of the skin, eye, barbel, and fins of spawn of an air-breathing teleost (Clarias batrachus, Linn. 1758) induced by UV-B radiation (280-320 nm) at a dose (@4.07 × 10-20J/photon/m2) under the time-frame of 5, 10 and 15 min/d in the laboratory condition for the periods of 5 and 10 days. Limnological parameters revealed no significant changes throughout the period of experimentation which were measured by PCS Testr 35 Multi-Parameter. Morphometric analysis revealed that during the extended exposure period of 10 days the spawn size and weight were reduced as analysed through Specific Growth Rate (SGR). SGR values in terms of weight for 5 and 10 days under 3 time-frames were 17.12%, 12.52%, 11.46% and 9.09%, 6.43%, 6.09% respectively, which revealed a declined trend along with the exposure days. In the skin of C. batrachus, the compact regular orientation of the stratified epithelial cells and mucous cells became distorted and the microridges and double-ridged structures showed destruction and fragmentations. The body striations and microfolds became shrinked and swollen and finally degenerated to form a mass. The distribution of mucous cells throughout the epidermis was disorganised and releasing secretory contents on the surface through small pores. Appearance of huge quantity of biogenic semi-hexagonal plate like crystals (guanine platelets) on the skin surface of the body was the most significant observations during UV-B radiation. In the developmental phases the eyeball showed shrinkage loosing normal regular concave structure and to become a dome-shaped one. The supportive connective infoldings became loosened. The choroid coat displayed deformities and the iris deformed the pupil. The fibroblast on the epithelium and melanocytes depicted dispersed arrangement. The pairs of ventral barbels near the mouth depicted the presence of taste buds that became severely damaged exposing the sensory as well as neuroepithelial cells. Compact regular arrangement of the SECs was completely destroyed leaving long and deep channels inbetween them; the disintegrated concentric MRs also showed a mass.


Assuntos
Nadadeiras de Animais/efeitos da radiação , Peixes-Gato , Olho/efeitos da radiação , Pele/efeitos da radiação , Raios Ultravioleta/efeitos adversos , Nadadeiras de Animais/ultraestrutura , Animais , Relação Dose-Resposta à Radiação , Epiderme/efeitos da radiação , Epiderme/ultraestrutura , Epitélio/efeitos da radiação , Epitélio/ultraestrutura , Olho/ultraestrutura , Pele/ultraestrutura
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA