Made available in DSpace on 2014-08-13T14:50:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-08-22Bitstream added on 2014-08-13T18:01:17Z : No. of bitstreams: 1 000725296_20150101.pdf: 109418 bytes, checksum: cebf9f97c8e08074ee65a1e7f67f9863 (MD5) Bitstreams deleted on 2015-01-05T11:00:50Z: 000725296_20150101.pdf,Bitstream added on 2015-01-05T11:01:48Z : No. of bitstreams: 1 000725296.pdf: 956123 bytes, checksum: 50d72cefdb85fffba1d5001620776c3f (MD5) / Este estudo foi realizado para caracterizar os achados dermatológicos, oftalmológicos e morfológicos da pele de cavalos com Astenia Dérmica Regional Hereditária Equina (HERDA) e padronizar um ensaio de “High Resolution Melting” (HRM), para determinar a ocorrência de heterozigotos. As avaliações e a padronização do HRM foram realizadas em cinco cavalos afetados (GA) e cinco não afetados (GC). Adicionalmente, cinco animais heterozigotos (GH) foram utilizados para padronizar o HRM. A ocorrência de heterozigotos foi determinada em 690 animais. Diversas regiões da pele foram mensuradas com cutímetro no GA e GC. Biópsias de pele foram submetidas aos exames histopatológico e ultraestrutural. Avaliação histopatológica foi realizada por dois patologistas. O exame oftalmológico incluiu, além das avaliações rotineiras, aferição dos diâmetros da córnea, paquimetria e biometria. Foi extraído DNA do sangue colhido do GA, GC, GH e de 690 cavalos e o HRM foi validado. Observou-se menor espessura de pele no GA. A sensibilidade e especificidade do diagnóstico histopatológico da pele dependeram do avaliador e da região, respectivamente. Foram observados menor espessura e maior curvatura e diâmetros da córnea no GA. O HRM apresentou elevadas acurácia e precisão. A frequência de heterozigotos foi de 4,7%. Apesar do padrão regional dos sinais dermatológicos, a diminuição da espessura da pele não é regional. Para o diagnóstico histopatológico, recomenda-se realizar biópsia de pele no pescoço, garupa ou dorso. A relevância clínica dos achados oftalmológicos deve ser investigada. O ensaio de HRM padronizado será útil na seleção dos acasalamentos, visando minimizar a ocorrência da doença / The present study was conducted to characterize the dermatological, ophthalmological, and morphological findings from horses affected with Hereditary Equine Regional Dermal Asthenia (HERDA) and to standardize a High Resolution Melting (HRM) genotyping assay to determine the frequency of carriers. The evaluations and HRM standardization were performed in five affected (AG) and five non-affected (CG) horses. Additionally, five heterozygous (HG) horses were used to HRM standardization. The frequency of carriers was determined in 690 horses. Several skin regions of both groups were measured with a cutimeter Skin biopsies were submitted to histopathological and ultrastructural evaluations. Histopathological evaluation was performed by two pathologists. Ophthalmology included, besides the routine evaluations, corneal diameters measurement, pachymetry, and biometry. HRM was validated using purified DNA from blood samples of the AG, CG, HG and 690 horses. Skin thickness decrease was observed in the AG. Histopathological sensitivity and specificity to diagnose HERDA was dependent on the evaluator and region, respectively. HERDA horses exhibited decreased corneal thickness and increased corneal curvature and corneal diameters. The HRM assay resulted in high accuracy and precision. The estimated carrier frequency was 4.7%. Despite of the regional pattern of the dermatological signs, the decrease of skin thickness from HERDA horses is not regional. Skin samples of the neck, croup or back are recommended to diagnose HERDA. The relevance of the ocular findings should be further investigated. The standardized HRM assay will be useful in the management of breeding programs to minimize the occurrence of this disease

I choose the topic of phototherapy because of my longlasting interest in this field. Phototherapy is defined as the therapeutic use of light, primarily ultraviolet light. The mode of action on the skin is described as photobiological one and it has been continuously investigated. At its most basic level phototherapy represents the application of energy to skin, which means the delivery of photons to chromophores, the absorbtion of photons in chromophores and the biologic reaction of photon's absorbed energy. This causes the formation of heat and various biochemical effects in the skin. Previously the main role of UV light in phototherapy was thought to be the antimitotic and antiproliferative. Nowadays it is clear that beside them the mode of action is rather immunomodulatory and immunosuppressive. Further possible mechanism of the UV light are detected with increasing investigation of the immune system of skin. The rules and usages of phototherapy in practice at individual dermatological departments and offices differ and there is a need to improve and/or coordinate the protocols in order to reach the optimal risk/benfit ratio. That was one of the reasons for conducting the epidemiological study Phototherapy in Czech Republic. The results shows phototherapy to be an available and relative...

Introduction: Malignant Melanoma is the most lethal of the skin cancers and the UK incidence is rising faster than that of any other cancer. Breslow thickness remains the best predictor of metastasis and Sentinel Lymph Node Biopsy is the only method of detecting nodal spread in clinically node negative patients. Surgery is the only effective therapy. Angiogenesis – the growth of new vessels from pre-existing vasculature - is an absolute requirement for tumour survival and progression beyond a few hundred microns in diameter. Anti- angiogenic isoforms of VEGF have been demonstrated previously to be protective with regard to metastasis. The aims of this thesis were to determine whether VEGF expression within the tumour may allow prediction of the nodal status. Furthermore another aim was to determine whether via the “Seed and Soil” theory, by examination of angiogenic and lymphangiogenic profiles of the tumour and node can we determine that the tumour may control the microenvironment around the Sentinel Node? Finally, as a cohort of false negative patients emerged with a higher mortality rate than their true negative and true positive patient cohort counterparts, could any further patterns be established by performing the same experiments on these patients? Methods: Archived human tumour and corresponding Sentinel Node samples were used and immunohistochemistry was used to investigate the role of pro and anti angiogenic isoforms of VEGF, VEGF-C, LYVE-1 and CD31 within these patients. Results: VEGF-C expression was significantly increased in the intranodal component of positive Sentinel Lymph Nodes (p < 0.01 Bonferroni). This increased expression appeared to be independent of tumoural influences and no strong evidence for the “Seed and Soil” theory was proved. A significantly higher number of lymphatic vessel counts were identified within node negative patients (p < 0.05 ANOVA). No further significant findings were defined on examination of the false negative cohort of patients. Conclusions: This study has shown that positive Sentinel Lymph Nodes exhibit high levels of intranodal VEGF-C. This expression does not appear to be related to tumoural influences. It would therefore appear that VEGF-C expression within Sentinel Nodes warrants further investigation and may aid diagnosis of spread or represent a target to slow or even prevent the onset of metastasis.

Orientador: Alexandre Secorun Borges / Banca: Carlos Alberto Hussni / Banca: João Pessoa Araújo Junior / Banca: Luiz Claudio Nogueira Mendes / Banca: Paulo Henrique Jorge da Cunha / Resumo: Este estudo foi realizado para caracterizar os achados dermatológicos, oftalmológicos e morfológicos da pele de cavalos com Astenia Dérmica Regional Hereditária Equina (HERDA) e padronizar um ensaio de "High Resolution Melting" (HRM), para determinar a ocorrência de heterozigotos. As avaliações e a padronização do HRM foram realizadas em cinco cavalos afetados (GA) e cinco não afetados (GC). Adicionalmente, cinco animais heterozigotos (GH) foram utilizados para padronizar o HRM. A ocorrência de heterozigotos foi determinada em 690 animais. Diversas regiões da pele foram mensuradas com cutímetro no GA e GC. Biópsias de pele foram submetidas aos exames histopatológico e ultraestrutural. Avaliação histopatológica foi realizada por dois patologistas. O exame oftalmológico incluiu, além das avaliações rotineiras, aferição dos diâmetros da córnea, paquimetria e biometria. Foi extraído DNA do sangue colhido do GA, GC, GH e de 690 cavalos e o HRM foi validado. Observou-se menor espessura de pele no GA. A sensibilidade e especificidade do diagnóstico histopatológico da pele dependeram do avaliador e da região, respectivamente. Foram observados menor espessura e maior curvatura e diâmetros da córnea no GA. O HRM apresentou elevadas acurácia e precisão. A frequência de heterozigotos foi de 4,7%. Apesar do padrão regional dos sinais dermatológicos, a diminuição da espessura da pele não é regional. Para o diagnóstico histopatológico, recomenda-se realizar biópsia de pele no pescoço, garupa ou dorso. A relevância clínica dos achados oftalmológicos deve ser investigada. O ensaio de HRM padronizado será útil na seleção dos acasalamentos, visando minimizar a ocorrência da doença / Abstract: The present study was conducted to characterize the dermatological, ophthalmological, and morphological findings from horses affected with Hereditary Equine Regional Dermal Asthenia (HERDA) and to standardize a High Resolution Melting (HRM) genotyping assay to determine the frequency of carriers. The evaluations and HRM standardization were performed in five affected (AG) and five non-affected (CG) horses. Additionally, five heterozygous (HG) horses were used to HRM standardization. The frequency of carriers was determined in 690 horses. Several skin regions of both groups were measured with a cutimeter Skin biopsies were submitted to histopathological and ultrastructural evaluations. Histopathological evaluation was performed by two pathologists. Ophthalmology included, besides the routine evaluations, corneal diameters measurement, pachymetry, and biometry. HRM was validated using purified DNA from blood samples of the AG, CG, HG and 690 horses. Skin thickness decrease was observed in the AG. Histopathological sensitivity and specificity to diagnose HERDA was dependent on the evaluator and region, respectively. HERDA horses exhibited decreased corneal thickness and increased corneal curvature and corneal diameters. The HRM assay resulted in high accuracy and precision. The estimated carrier frequency was 4.7%. Despite of the regional pattern of the dermatological signs, the decrease of skin thickness from HERDA horses is not regional. Skin samples of the neck, croup or back are recommended to diagnose HERDA. The relevance of the ocular findings should be further investigated. The standardized HRM assay will be useful in the management of breeding programs to minimize the occurrence of this disease / Doutor

Trichodysplasia spinulosa (TS) é uma doença proliferativa de pele observada em pacientes imunocomprometidos. Caracteriza-se pela formação de espinhas de queratina conhecidos como espículas, acantose epidérmica, dilatação do folículo piloso, queratose actínica, queda dos pelos, pápulas foliculares e, que normalmente, se manifestam na região facial do paciente e extremidades do corpo (constantemente confundida com danos por exposição prolongada ao sol). A TS resulta da infecção ativa com o poliomavírus TSassociado (TSPyV), onde observa-se alta carga viral, expressão de proteína do vírus e formação de partículas. Este estudo desenvolveu métodos moleculares de detecção e sequenciamento do genoma total e parcial de TSPyV e utilizou-se destes métodos para determinar padrões de excreção e viremia em indivíduos imunocompromentidos e imunocompetentes, bem como explorar possíveis vias de transmissão. Ainda, características genéticas e filogenéticas do TSPyV também foram determinadas. Apesar de observamos alta taxa de excreção urinaria em indivíduos imunocomprometidos (57,7%), o vírus não foi encontrado em amostras de água do meio ambiente. Ainda em termos de excreção urinária do TSPyV, apenas 1,4% dos indivíduos imunocompetentes apresentaram virúria (diferente do que se observa para os poliomavirus JCPyV e BKPyV), mas o vírus foi encontrado em leite materno, sugerindo assim a possibilidade de haver transmissão vertical do TSPyV. As análises filogenéticas revelaram a existência de 2 linhagens de vírus circulantes em nosso meio, com características distintas dos já descritos na literatura. As diferenças observadas foram suficientes para que os vírus sejam caracterizados como novos genótipos circulantes de TSPyV. / Trichodysplasia spinulosa (TS) is a proliferative skin disease seen in immunocompromised patients. It is characterized by the formation of keratin spines known as spicules, epidermal acanthosis, hair follicle dilatation, actinic keratosis, hair loss, follicular papules and, which usually manifest in the facial region and extremities of the body (constantly confounded with damage from prolonged exposure to the sun). TS results from active infection with TS-associated polyomavirus (TSPyV), where high viral load, virus protein expression and particle formation are observed. This study developed molecular methods for detection and sequencing the total and partial genome of TSPyV and, employing these methods, determined patterns of excretion and viremia in immunocompromised and immunocompetent individuals, as well as explored possible transmission pathways. Genetic and phylogenetic characteristics were also determined. Although we observed high rate of urinary shedding in immunocompromised individuals (57.7%), the virus was not found in environmental water samples. Also in terms of urinary excretion of TSPyV, only 1.4% of immunocompetent individuals presented viruria (different from what is observed for polyomaviruses JCPyV and BKPyV), but the virus was found in breast milk, thus suggesting the possibility of vertical transmission. Phylogenetic analyzes revealed the existence of 2 circulating virus strains in our country, with different characteristics from those already described in the literature. The differences seem to be sufficient to characterize the viruses as new genotypes of TSPyV.

Introdução: A hanseníase pode acometer a pele e o sistema nervoso periférico podendo levar a graves deformidades. É causada pelo Mycobacterium leprae, bacilo álcool-ácido resistente, parasita exclusivamente intracelular. Atualmente, a hanseníase é classificada em dois grandes grupos: paucibacilar (menos de cinco lesões) e multibacilar (mais de cinco lesões). É um problema de saúde pública, estando o Brasil entre os países de maior endemicidade no mundo. A morbidade dessa doença milenar se deve ao fato de causar incapacidades, por vezes irreversíveis, além do estigma que a acompanha, levando ao comprometimento da qualidade de vida. Vários trabalhos têm sido realizados a respeito da qualidade de vida em doenças dermatológicas, como psoríase, dermatite atópica, acne, herpes genital, hanseníase, no sentido de se tentar avaliar o grau de comprometimento do bem-estar físico, psicossocial e de atividades da rotina diária, assim como se tentar melhorar a relação médico-paciente e das ações de saúde, com o intuito de se minimizar os problemas decorrentes de cada enfermidade. Objetivo: avaliar o comprometimento da qualidade de vida nos pacientes do grupo paucibacilar de hanseníase em tratamento ambulatorial. Métodos: aplicação dos questionários Dermatology Life Quality Index e Short Form-36. O Dermatology Life Quality Index é um questionário específico para a dermatologia e é constituído de 10 questões, cujo escore varia de zero a 30, sendo o máximo valor (30) relacionado ao maior comprometimento da qualidade de vida. O Short Form-36, questionário mais genérico, abrange oito domínios (Capacidade Funcional, Aspectos físicos, Dor, Estado geral de saúde, Vitalidade, Aspectos sociais, Aspectos emocionais e Saúde mental), distribuídos em 11 questões, cada qual com número variável de itens, perfazendo 36 itens, que nos dá um escore que pode variar de zero a 100, sendo o maior escore (100) atribuído ao menor comprometimento da qualidade de vida. Foram aplicados esses dois questionários em 49 doentes com hanseníase do grupo paucibacilar. Resultados: Dos 49 pacientes que participaram do estudo, 36 do sexo feminino e 13 do sexo masculino, a maioria (63%) não apresentou comprometimento da qualidade de vida, de acordo com os resultados obtidos através do questionário Dermatology Life Quality Index. Ao aplicar o questionário genérico Short Form - 36, os escores alcançados nos diversos domínios também demonstraram pouco comprometimento da qualidade de vida no grupo estudado / Introduction - Leprosy can affect the skin and peripheral nervous system and can lead to severe deformities. It is caused by Mycobacterium leprae, Bacillus acid-resistant, an intracellular parasite exclusively. Currently, leprosy is classified into two major groups: paucibacillary (less than five lesions) and multibacillary (more than five lesions). It is a public health problem, with Brazil among the countries with the highest endemicity in the world. The millennial morbidity of this disease is due to the fact that causes disabilities, sometimes irreversible, besides the stigma that accompanies it, compromising the quality of life. Several studies have been conducted regarding the quality of life in dermatological diseases such as psoriasis, atopic dermatitis, acne, genital herpes, leprosy, in order to try to assess the degree of impairment of physical well-being, psychosocial and daily routine activities as well as try to improve the doctor-patient relationship and health actions in order to minimize problems arising from each disease. Objective: To assess the actual quality of life for patients in group paucibacillary leprosy outpatients. Methods: application of the Dermatology Life Quality Index questionnaire and Short Form-36. The Dermatology Life Quality Index is a dermatology-specific questionnaire and consists of 10 questions which score ranges from zero to 30, with the maximum value (30) related to greater impairment of quality of life. The Short Form-36, more generic questionnaire covers eight domains (Physical Functioning, Role Physical, Pain, General Health, Vitality, Social, Emotional and Mental Health Aspects), distributed in 11 questions, each with varying number of items, totaling 36 items, which gives a score that can range from zero to 100, with the highest score (100) assigned to lower impairment of quality of life. These two questionnaires were applied in 49 patients with paucibacillary leprosy group. Results: Of 49 patients who participated in the study, 36 females and 13 males, most (63%) did not show quality of life compromising, according to the results obtained by the Dermatology Life Quality Index questionnaire. By applying the generic questionnaire SF - 36, the scores achieved in several domains also showed little decrease in quality of life in the studied group

Para analisar a efetividade da teledermatologia assistencial a partir de fotografias digitais de lesões, avaliou-se a sistematização de aspectos técnicos, morfológicos (maculoso, relevo e palpatório) e de representatividade clínica (típico, moderado e atípico). Verificou-se que o comprometimento da qualidade técnica, a morfologia palpatória e menor tipicidade clínica devem ser suplementados pela descrição das lesões e pelas informações clínicas para aumentar sua acurácia diagnóstica. Desenvolveu-se um sistema de interconsulta dermatológica à distância e constatou-se que seu desempenho diagnóstico foi comparável à consulta presencial, devendo ser consideradas todas as hipóteses diagnósticas elaboradas, além da principal / To analyze the effectiveness of a teledermatology system, the systematization of digital photographs from cutaneous lesions on technical quality, morphologic and clinical aspects was performed. The study showed that unsatisfactory technical quality, palpatory morphology and less typical lesions should be supplemented by clinical description of the lesions and patient information to increase diagnostic accuracy. The dermatologic Internet-based teleconsultation system has diagnostic performance comparable to face-to-face consultation, and all the hypotheses, not only first one, should be considered at virtual diagnostic evaluation

Leishmania parasites are digenetic protozoans which infect human hosts and are causative agents of a series of diseases known under the name of leishmaniasis. Macrophages represent the main host. Hence the interaction between Leishmania and macrophages is a fundamental step in the development of the disease. Many studies have been undertaken to understand early stages of the parasite interaction with macrophages; however, few have investigated the later stages of infection. This study was undertaken to develop an experimental model to examine the fate of the parasites when they leave the safe environment represented by their host macrophage. Primarily, the study investigated how Leishmania spread to neighbouring cells without being recognized and killed by the immune system defences. Three Old World species of Leishmania parasites: L. aethiopica, L. major and L. tropica, all responsible for the cutaneous form of the disease, were used. A model of infection was described using two cell lines well known for supporting infection: THP-1 and U937. Axenic amastogotes for L. aethiopica parasites were obtained and used to identify drugs active against the infection. On the basis of the information available in the literature, a model was suggested involving interaction of intracellular parasites with the host cells’ apoptotic machinery. Specifically it was suggested that Leishmania parasites were able to induce incomplete activation of apoptosis in the host cells. This hypothesis was confirmed by the findings that during infection an increased number of host cells showed two features associated with early apoptosis but not the one associated with the later stage. Results were validated in peripheral blood derived human macrophages. The information obtained from comparative proteomics analysis of the infection confirmed that Leishmania regulates apoptotic processes. On the basis of the results obtained a model was presented to explain how induction of apoptosis allows intracellular amastigotes to spread unrecognised to uninfected macrophages without inducing an inflammatory response or losing the host cell’s protection.

Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa are the main multi-drug resistant pathogens associated with deep wound infections which then may cause septicaemia. Treatment is problematic and re-infection is quite common. Free Living Amoebae (FLA), such as Acanthamoeba, are widely distributed in the environment and may also contaminate wounds. It is well known that Acanthamoeba feed on and protect bacteria. The role of Acanthamoeba in wound infections is not very well understood. It is possible that the presence of Acanthamoeba in wounds is one of the key factors for such re-infections. In this study, 140 wound swabs were collected to check for the presence of Acanthamoeba spp. Only one sample was positive for Acanthamoeba spp. Sequencing of the highly variable DF3 region of 18S rRNA gene for the sample showed that this isolate belongs to genotype T4. In addition, clinical isolates of MRSA and Pseudomonas from wound infections were used in this study. The results showed that MRSA and Pseudomonas were able to bind with, invade, survive and multiply inside Acanthamoeba species. One of the essential compounds for microorganisms to grow is iron. The role of iron chelators, including deferiprone and selected novel compounds based on hydroxyl pyridine moiety, was studied. Findings revealed that all novel iron chelators have an antimicrobial activity against both bacteria. In addition, all novel iron chelators were able to kill Acanthamoeba. Cytotoxic effects of MRSA, P. aeruginosa and Acanthamoeba were investigated using the KB epithelial cell line and mesenchymal stem cells (MSC) using a general caspase inhibitor. The results revealed that the ability of live bacteria to induce cell death was higher compared with heat-killed bacteria, bacteria conditioned medium (BCM) and Acanthamoeba conditioned media (CM). The exact trigger for the cell death in this study was not investigated but the relative contributions of apoptosis and necrosis were investigated using fluorescent technique, caspase inhibition and LDH assay. In conclusion, presence of Acanthamoeba in wounds could be the reason of prolong treatment and reinfection in wounds.

Ultraviolet A is a major spectral component of solar electromagnetic energy reaching the surface of the earth. Excessive exposure to solar UVA is a known contributor to skin photoaging and photocarcinogenesis, associated with increased incidence rates and a significant health burden imposed by skin cancer worldwide. However, the molecular mechanisms underlying UVA-induced skin photodamage remain largely undefined. UVA radiation has been shown to cause cutaneous oxidative stress and photosensitization reactions involving the light-driven photochemistry of specific skin chromophores upstream of reactive oxygen species formation, recognized as key players in skin photooxidative damage. Consequently, there has been significant interest in the identification of endogenous compounds that facilitate these reactions serving as endogenous photosensitizers. In my graduate research, we assessed the potential of selected endogenous chromophores, pyridoxal and 6-formylindolo[3,2-b]carbazole (FICZ), to elicit UVA-induced photo- and genotoxicity in relevant models of human skin, and further identified the underlying molecular mechanisms involved. We demonstrated for the first time that the B6-vitamer pyridoxal, previously shown to contain the phototoxic 3-hydroxypyridine moiety, is a micromolar sensitizer of UVA-induced genotoxicity in human primary keratinocytes and human epidermal reconstructs, which may be relevant to human skin exposed to high concentrations of B6-vitamers. Additionally, we have demonstrated that FICZ, a tryptophan photoproduct and endogenous high-affinity aryl hydrocarbon receptor (AhR) agonist, as the most potent endogenous UVA- and visible light-activated photosensitizer identified as of today. FICZ potentiates photooxidative stress, an effect that occurs independent of AhR ligand activity. Given the extraordinary photodynamic potency of FICZ, which surpasses that of any known endogenous photosensitizer, including protoporphyrin IX, and its rapid metabolic turnover, we tested the feasibility of using FICZ for the photodynamic elimination of malignant skin cancer cells in vitro and in vivo. Indeed, light photoactivation of FICZ-induced phototoxidative damage and cytotoxicity in a panel of cultured human malignant skin cells, and furthermore suppressed post-UVB tumorigenic progression in high-risk SKH-1 mice. Based on these pilot studies, follow up experiments will further optimize FICZ-based photodynamic interventions targeting human skin malignancies in relevant model systems. In pursuit of minimizing the need for invasive therapeutic methods, exploitation of stress response pathways has become a topic of interest for interventions aimed at the eradication of skin cancer at early or late progressional stages. Therefore, we tested feasibility of harnessing the cellular metal stress response for the elimination of skin cancer cells using the zinc-ionophore and FDA-approved microbicidal agent zinc pyrithione (ZnPT). Indeed, in a panel of cultured malignant skin cancer cells it was observed that ZnPT treatment caused rapid intracellular zinc overload and redox dysregulation, followed by a loss of genomic integrity and induction of caspase-independent cell death. In a murine photocarcinogenesis model, chronic topical ZnPT-administration post-UV caused epidermal zinc-overload and stress response gene expression with pronounced blockade of tumorigenic progression. These data suggest the feasibility of repurposing a topical OTC-drug for zinc-directed photochemoprevention of solar UV-induced nonmelanoma skin cancer. In summary, these studies contribute to our mechanistic understanding of photosensitizer- and zinc-induced stress responses in human skin, and furthermore provide the molecular basis for innovative therapeutic strategies aimed at the elimination of skin cancer cells.