954 resultados para RAYLEIGH-TAYLOR INSTABILITY


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The larynx is the third most commonly involved organ in paracoccidioidomycosis (PCM). While a few studies have evaluated laryngeal sequelae, there have not been any investigations of voice abnormalities in PCM patients. To evaluate persistent dysphonia and laryngeal lesions, we studied 15 normal subjects and 30 post-treatment PCM patients, i.e., 15 with only pulmonary and 15 with both laryngeal and pulmonary involvement. Perceptual and acoustic voice analysis were performed with all patients, while endoscopic studies were also conducted with the 15 laryngeal patients. Voice analysis showed instability by perceptual analysis (P < 0.01) in both groups, but more severe dysphonia was noted in the laryngeal group (P < 0.01). The dysponia, seen in 66.7% of these patients (dysphonia index < 7.0), was characterized by roughness and breathness. The Dr. Speech (Tiger Electronics) analysis program did not accept five voices from the laryngeal group due to the severe dysphonia. Jitter was elevated in five laryngeal lesion patients. Endoscopy showed that 80% of patients with laryngeal lesion had two or more laryngeal structures involved. Vocal fold alterations were seen in all laryngeal lesion patients, which included involvement of the arythenoids, epiglottis, and vestibular folds. This first functional study of laryngeal sequelae in PCM revealed frequent and severe dysphonia that may have important social consequences for patients.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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4-Nitroquinotine 1-oxide (4NQO)-induced rat tongue carcinogenesis is a useful model for studying oral squamous cell carcinoma. The aim of this study was to investigate the level of DNA damage induced by 4NQO in oral mucosa cells by the single cell get (comet) assay. Mate Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution by drinking water for 4, 12 or 20 weeks. Ten animals were used as negative control. Statistically significant increase of DNA damage was observed in non-neoplastic oral cells at four weeks of 4NQO administration when compared with control (P < 0.05). The level of DNA damage was directly associated with the severity of histological changes. The results suggest that histologically normal tissue is able to harbor genetically unstable cells contributing to the initiation of oral carcinogenesis. Genomic instability appears to be associated with the risk and progression of oral cancer. (C) 2004 Elsevier Ltd. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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OBJECTIVE: Propose a new experimental model of bladder instability in rabbits after partial bladder obstruction. MATERIALS and METHODS: Thirty North Folk male rabbits, weighting 1,700 to 2,820 g (mean: 2,162 g) were studied. The animals were distributed in 2 experimental groups, formed by 15 rabbits each: Group 1 - clinical control. In this group there was no surgical intervention; Group 2 - bladder outlet obstruction. In this group, after anesthetizing the animal, urethral cannulation with Foley catheter 10F was performed and then an adjustable plastic bracelet was passed around the bladder neck. It was then adjusted in order to not constrict the urethra. The following parameters were studied in M1 - pre-operative period; M2 - 4 weeks post-operatively moments: 1)- urine culture; 2)- cystometric study; 3)- serum creatinine and BUN. RESULTS: Bladder weight was 2.5 times larger in the group with obstruction than in the control group. Cystometric evaluation showed a significant increase in maximal vesical volume in the final moment at Group G2. However, there was no statistically significant difference among the groups studied. There was no statistically significant difference between maximal detrusor pressure and vesical compliance in the different moments or in the studied groups. There was an absence of uninhibited detrusor contractions in all the animals in group 1, and involuntary contractions were detected in 93% of group 2 animals. There was no significant variation in BUN and serum creatinine either among the groups or in the same group. CONCLUSIONS: We observed in the group with obstruction a bladder weight 2.5 higher than normal bladders. We detected involuntary contractions in 93% of the animals in group 2, establishing this experimental model as appropriate to secondary bladder instability and partial bladder outlet obstruction.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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We employ a time- dependent mean- field- hydrodynamic model to study the generation of bright solitons in a degenerate fermion - fermion mixture in a cigar- shaped geometry using variational and numerical methods. Due to a strong Pauli- blocking repulsion among identical spin- polarized fermions at short distances there cannot be bright solitons for repulsive interspecies interactions. Employing a linear stability analysis we demonstrate the formation of stable solitons due to modulational instability of a constant-amplitude solution of the model equations for a sufficiently attractive interspecies interaction. We perform a numerical stability analysis of these solitons and also demonstrate the formation of soliton trains by jumping the effective interspecies interaction from repulsive to attractive. These fermionic solitons can be formed and studied in laboratory with present technology.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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A partir de reflexão sobre uma hipotética transição do capitalismo em sua natureza manufatureira ao socialismo, procura-se deixar marcada a razão pela qual, seguindo a proposta de Marx, essa transição exige que a produção se realize sob a égide da maquinaria. Consegue-se, como parte dessa reflexão, identificar, para o caso da manufatura, um trade-off entre eficiência produtiva e humanização das atividades de trabalho. Procura-se esclarecer que, dada a natureza do taylorismo-fordismo como reinvenção da manufatura, o exercício de início especulativo passa a ter sentido histórico. Busca-se argumentar que a ampla assimilação do taylorismo-fordismo pela experiência de implantação do socialismo na União Soviética a aprisionou ao mencionado trade-off , fazendo com que a primeira experiência de superação do capitalismo se impregnasse perversamente da mediocridade imanente ao taylorismo-fordismo. Finalmente, são feitos rápidos comentários acerca dos desdobramentos da recente automação de base microeletrônica sobre a natureza de um projeto socialista.

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CONTEXTO: Vários estudos de perda de heterozigozidade na região 9p21-p22, que abriga os genes supressores tumorais CDKN2a/p16INK4a, p19ARF e p15INK4b, têm sido realizados em uma ampla série de tumores humanos, incluindo os melanomas familiares. Perdas e ganhos em outras regiões do cromossomo 9 também têm sido observados com freqüência e podem indicar mecanismos adicionais no processo de tumorigênese dos carcinomas basocelulares da pele. OBJETIVO: Investigar o equilíbrio alélico existente na região 9p21-p22 em carcinomas basocelulares. TIPO DE ESTUDO: Análise molecular de marcadores de microssatélites em tumores e controles. LOCAL: Dois serviços de dermatologia de atendimento terciário em universidades públicas de São Paulo e o Laboratório de Genética Molecular do Câncer da Universidade Estadual de Campinas (UNICAMP), Brasil. PARTICIPANTES: Examinamos 13 casos benignos, incluindo 4 queratoses solares, 3 queratoacantomas, 3 nevos melanocíticos, 2 doenças de Bowen e 1 neurofibroma cutâneo, além de 58 tumores malignos da pele: 14 de células escamosas, 40 carcinomas basocelulares e 4 melanomas; em pacientes consecutivamente encaminhados à clínica de Dermatologia da Unicamp e que concordaram em participar do estudo. VARIÁVEIS ESTUDADAS: O tumor principal e uma porção normal de pele não-adjacente foram removidos cirurgicamente de pacientes que consecutivamente procuraram os ambulatórios de dermatologia da Universidade Estadual de Campinas (UNICAMP) e da Universidade Estadual de São Paulo (Unesp), São Paulo, por causa de lesões cutâneas. Extraímos DNA tanto de tecido tumoral como do correspondente tecido normal de cada paciente. Para amplificar regiões de repetição polimórfica de microssatélites do cromossomo 9, foram utilizados quatro pares de primers, sendo dois deles destinados à região 9p21-p22. RESULTADOS: Identificamos oito casos (20%) de desequilíbrio alélico entre os carcinomas basocelulares, sendo dois casos de perda de heterozigozidade e seis casos de instabilidade de microssatélite na região 9p21-p22. Outros marcadores também mostravam anormalidades em três destes tumores, enquanto nenhuma alteração foi detectada entre os casos benignos e nos outros tumores malignos. CONCLUSÃO: Esta dependência fenotípica sugere que existem diferenças importantes no comportamento das formas mais comuns de tumores cutâneos não-melanocíticos em relação à sua tendência para instabilidade de microssatélite no cromossomo 9. Considerando-se que os genes CDKN2a/p16INK4a, p19ARF e p15INK4b não parecem responsáveis pelas anormalidades observadas, outros genes em 9p21-p22 podem estar envolvidos na etiopatogenia e na progressão dos carcinomas basocelulares.

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After in vitro culture, we analyzed cytogenetically four acoustic nerve neurinomas, one intraspinal neurinoma and one neurofibroma obtained from unrelated patients. Monosomy of chromosomes 22 and 16 was an abnormality common to all cases, followed in frequency by loss of chromosomes 18 (three cases) and chromosomes 8, 17 and 19 (two cases). Trisomy of chromosome 20 was also detected in two cases. Structural rearrangements were detected at low frequencies, with del(10)(p12) being present in two cases. In addition, we observed cell subpopulations showing a certain degree of genetic instability, reflected by the presence of polyploid cells with inconsistent abnormalities, endoreduplications and telomeric associations resulting in dicentric chromosomes. It is probable that these cytogenetic abnormalities represent some kind of evolutionary advantage for the in vitro progression of nerve sheath tumors.