RESUMO

Usnic acid, a lichen metabolite, is known to exert antimitotic and antiproliferative activities against normal and malignant human cells. Many chemotherapy agents exert their activities by blocking cell cycle progression, inducing cell death through apoptosis. Microtubules, protein structure involved in the segregation of chromosomes during mitosis, serve as chemotherapeutical targets due to their key role in cellular division as well as apoptosis. The aim of this work was to investigate whether usnic acid affects the formation and/or stabilisation of microtubules by visualising microtubules and determining mitotic indices after treatment. The breast cancer cell line MCF7 and the lung cancer cell line H1299 were treated with usnic acid 29 µM for 24 hours and two positive controls: vincristine (which prevents the formation of microtubules) or taxol (which stabilizes microtubules). Treatment of MCF7 and H1299 cells with usnic acid did not result in any morphological changes in microtubules or increase in the mitotic index. These results suggest that the antineoplastic activity of usnic acid is not related to alterations in the formation and/or stabilisation of microtubules.

O ácido úsnico, um metabólito de liquens, é conhecido por sua atividade antimitótica e antiproliferativa em células humanas normais e malignas. Muitos quimioterápicos exercem suas atividades bloqueando a progressão do ciclo celular e induzindo morte celular por apoptose. Os microtúbulos, estruturas protéicas envolvidas na segregação dos cromossomos durante a mitose, servem como alvo quimioterapêutico devido ao seu importante papel tanto na divisão celular quanto nos mecanismos de morte celular por apoptose. O objetivo deste trabalho foi investigar se o ácido úsnico afeta a formação e/ou estabilização dos microtúbulos, a partir da visualização de microtúbulos e determinação de índices mitóticos após o tratamento. Células de câncer de mama MCF7 e de câncer de pulmão H1299 foram tratadas por 24 horas com 29 µM de ácido úsnico e dois controles positivos: vincristina (que impede a formação de microtúbulos) e taxol (que estabiliza microtúbulos). O tratamento das células MCF7 e H1299 com o ácido úsnico não resultou em aumento do índice mitótico. Os resultados sugerem que a atividade antineoplásica do ácido úsnico não está relacionada a alterações na formação e/ou estabilização de microtúbulos.

Assuntos

RESUMO

Usnic acid, a lichen metabolite, is known to exert antimitotic and antiproliferative activities against normal and malignant human cells. Many chemotherapy agents exert their activities by blocking cell cycle progression, inducing cell death through apoptosis. Microtubules, protein structure involved in the segregation of chromosomes during mitosis, serve as chemotherapeutical targets due to their key role in cellular division as well as apoptosis. The aim of this work was to investigate whether usnic acid affects the formation and/or stabilisation of microtubules by visualising microtubules and determining mitotic indices after treatment. The breast cancer cell line MCF7 and the lung cancer cell line H1299 were treated with usnic acid 29 µM for 24 hours and two positive controls: vincristine (which prevents the formation of microtubules) or taxol (which stabilizes microtubules). Treatment of MCF7 and H1299 cells with usnic acid did not result in any morphological changes in microtubules or increase in the mitotic index. These results suggest that the antineoplastic activity of usnic acid is not related to alterations in the formation and/or stabilisation of microtubules.(AU)

O ácido úsnico, um metabólito de liquens, é conhecido por sua atividade antimitótica e antiproliferativa em células humanas normais e malignas. Muitos quimioterápicos exercem suas atividades bloqueando a progressão do ciclo celular e induzindo morte celular por apoptose. Os microtúbulos, estruturas protéicas envolvidas na segregação dos cromossomos durante a mitose, servem como alvo quimioterapêutico devido ao seu importante papel tanto na divisão celular quanto nos mecanismos de morte celular por apoptose. O objetivo deste trabalho foi investigar se o ácido úsnico afeta a formação e/ou estabilização dos microtúbulos, a partir da visualização de microtúbulos e determinação de índices mitóticos após o tratamento. Células de câncer de mama MCF7 e de câncer de pulmão H1299 foram tratadas por 24 horas com 29 µM de ácido úsnico e dois controles positivos: vincristina (que impede a formação de microtúbulos) e taxol (que estabiliza microtúbulos). O tratamento das células MCF7 e H1299 com o ácido úsnico não resultou em aumento do índice mitótico. Os resultados sugerem que a atividade antineoplásica do ácido úsnico não está relacionada a alterações na formação e/ou estabilização de microtúbulos.(AU)

Assuntos

RESUMO

Usnic acid, a lichen metabolite, is known to exert antimitotic and antiproliferative activities against normal and malignant human cells. Many chemotherapy agents exert their activities by blocking cell cycle progression, inducing cell death through apoptosis. Microtubules, protein structure involved in the segregation of chromosomes during mitosis, serve as chemotherapeutical targets due to their key role in cellular division as well as apoptosis. The aim of this work was to investigate whether usnic acid affects the formation and/or stabilisation of microtubules by visualising microtubules and determining mitotic indices after treatment. The breast cancer cell line MCF7 and the lung cancer cell line H1299 were treated with usnic acid 29 microM for 24 hours and two positive controls: vincristine (which prevents the formation of microtubules) or taxol (which stabilizes microtubules). Treatment of MCF7 and H1299 cells with usnic acid did not result in any morphological changes in microtubules or increase in the mitotic index. These results suggest that the antineoplastic activity of usnic acid is not related to alterations in the formation and/or stabilisation of microtubules.

Assuntos

Assuntos

RESUMO

Do hospital services, like other services and commerce, contribute to the structuring of geographical regions, as proposed by central place theory? This question raises the issue of the rating of hospital facilities in land use planning policies. According to the theory, a polarized region forms around a central place due to the minimization of transport costs by consumers seeking to satisfy their needs. If a center offers more central functions (rare trades, services for individuals and businesses), its level in the urban hierarchy is raised and its area of influence expands. This theory was validated using a model, the variant of the gravitation model proposed by Huff. Brazil is an excellent testing ground for these hypotheses due to the great variety of geographic situations, economic and social development levels and the availability of sufficient data. Geographic research has resulted in the construction of an urban center hierarchy based on central functions, and the Unified Health System (or SUS) systematically records authorizations for hospital admission (or AIH) throughout the country. Processing of the 12 million AIH for 1996 showed that in a quarter of cases, the individual was admitted to hospital in a town other than their town of residence (exogenous AIH). Mapping the percentage of exogenous AIH makes it possible to delimit the area of influence of health services (observed influence) for the whole of Brazil. In Minas Gerais State, these areas of influence were compared with the estimates made according to the Huff model (calculated influence), with adjustment for distance and the number of hospital beds. Differences between the observed and calculated areas of influence are due to factors not taken into account by the model, such as the heterogeneity of many regions in the country. However, the accuracy of the estimation is satisfying, as is the simplicity of the equations. All the results tend towards a single conclusion: hospital services play a major role in the structuring of geographic space, by increasing the attraction potential of urban centers.

Assuntos

RESUMO

OBJECTIVE: To compare the acceptability, compliance, and effectiveness of two forms of cholestyramine resin in the treatment of hypercholesterolemia in children. STUDY DESIGN: Patients aged 10 to 18 years with familial hypercholesterolemia were enrolled in a randomized, crossover trial of two 8-week periods of either a pill or powder form of cholestyramine at a dose of 8 gm/day. RESULTS: Of 40 children enrolled, 38 completed both medication periods, with a median age of 13 years (range, 10 to 18). At the end of the study, 82% preferred the pill form, 16% the powder form and 2% neither form. Mean (+/-SD) compliance as assessed by the amount of medication taken was significantly greater for pills (61% +/- 31%) than powder (50% +/- 30%, p = 0.01). The form of the medication increased compliance by at least 25% for 16 patients (42%), 13 in favor of pills and 3 in favor of powder. Compliance was not associated with patient attitudes and perceptions of hypercholesterolemia, demographics, family history, previous experience with lipid-lowering medication, or lipid profile parameters. Significant mean reductions in low-density lipoprotein cholesterol concentrations were noted for both pills (-10% +/- 20%, p = 0.006) and powder (-15% +/- 17%, p = 0.0001), with no significant difference between forms (p = 0.16). CONCLUSIONS: A change in bile acid-binding resin formulation from powder to pills significantly increases acceptability and compliance in some children with hypercholesterolemia.

Assuntos

RESUMO

Extracts prepared from Simarouba amara fruits collected in Panama have been found to be active against Plasmodium falciparum in vitro and against Plasmodium berghei in mice. Four active quassinoids have been identified as ailanthinone, 2'-acetylglaucarubinone, glaucarubinone and holacanthone.

Assuntos

Assuntos