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1.
Int J Radiat Oncol Biol Phys ; 71(1): 281-9, 2008 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-18406892

RESUMO

PURPOSE: Respiratory motion presents a significant challenge in stereotactic body radiosurgery. Respiratory tracking that follows the translational movement of the internal fiducials minimizes the uncertainties in dose delivery. However, the effect of deformation, defined as any changes in the body and organs relative to the center of fiducials, remains unanswered. This study investigated this problem and a possible solution. METHODS AND MATERIALS: Dose delivery using a robotic respiratory-tracking system was studied with clinical data. Each treatment plan was designed with the computed tomography scan in the end-expiration phase. The planned beams were applied to the computed tomography scan in end-inspiration following the shift of the fiducials. The dose coverage was compared with the initial plan, and the uncertainty due to the deformation was estimated. A necessary margin from the clinical target volume to the planning target volume was determined to account for this and other sources of uncertainty. RESULTS: We studied 12 lung and 5 upper abdomen lesions. Our results demonstrated that for lung patients with properly implanted fiducials a 3-mm margin is required to compensate for the deformation and a 5-mm margin is required to compensate for all uncertainties. Our results for the upper abdomen tumors were still preliminary but indicated a similar result, although a larger margin might be required. CONCLUSION: The effect of body deformation was studied. We found that adequate dose coverage for lung tumors can be ensured with proper fiducial placement and a 5-mm planning target volume margin. This approach is more practical and effective than a recent proposal to combine four-dimensional planning with respiratory tracking.


Assuntos
Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/cirurgia , Movimento , Radiocirurgia/métodos , Respiração , Robótica/métodos , Neoplasias Abdominais/diagnóstico por imagem , Expiração , Ouro , Humanos , Pulmão/anatomia & histologia , Pulmão/diagnóstico por imagem , Neoplasias Pulmonares/patologia , Próteses e Implantes , Radiografia
2.
Riv Biol ; 100(1): 39-54, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17592818

RESUMO

Flavonoids are naturally occurring polyphenolic plant compounds that are capable of inhibiting histamine and cytokine release from several cells. Many studies suggest that flavonoids are anticancer agents with an apoptotic effect on tumor cells. Studies with animal tumour models have found vitamin deficiency to enhance susceptibility to chemical carcinogenesis and large doses of anti-oxidant vitamins and flavonoids to inhibit carcinogenesis. In some studies flavonoids and/or vitamins were found to reduce the predisposition to develop tumours in animals and humans. In conclusion, in this review we describe the role of flavonoids and vitamins in cancer.


Assuntos
Flavonoides/uso terapêutico , Neoplasias/prevenção & controle , Vitaminas/uso terapêutico , Animais , Humanos
3.
Riv Biol ; 99(2): 227-49, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17115370

RESUMO

Protein-carbohydrate interactions are used for intercellular communication. Mammalian cells are known to bear a variety of glycoconjugates. Lectins, first discovered in plants, are proteins which can specifically bind carbohydrates. Given the high affinity of plant lectins for carbohydrates, they have always been important as molecular tools in the identification, purification and stimulation of specific glycoproteins on human cells. Lectins have provided important clues to the repertoire of carbohydrate structures in animal cells. The discovery of plant lectins gave a great impulse to modern glycobiology. They represent important biochemical reagents for numerous applications in the biomedical field and in research. Sequence determinations and structural characterization helped to understand the mechanism of action in many biologic systems. Plant lectins have been fundamental in human immunological studies because some of them are mitogenic/activating to lymphocytes. Understanding the molecular basis of lectin-carbohydrate interactions and of the intracellular signalling evoked holds promise for the design of novel drugs for the treatment of infectious, inflammatory and malignant diseases. It may also be of help for the structural and functional investigation of glycoconjugates and their changes during physiological and pathological processes.


Assuntos
Pesquisa Biomédica , Lectinas de Plantas/genética , Lectinas de Plantas/imunologia , Glicoproteínas/metabolismo , Humanos , Indicadores e Reagentes , Ligantes , Mitógenos/genética , Neoplasias/terapia , Lectinas de Plantas/metabolismo , Lectinas de Plantas/uso terapêutico , Plantas/metabolismo
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