8 resultados para substance

em Repositório da Produção Científica e Intelectual da Unicamp


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Multidrug-resistant microbial infections represent an exponentially growing problem affecting communities worldwide. Photodynamic therapy is a promising treatment based on the combination of light, oxygen, and a photosensitizer that leads to reactive oxygen species production, such as superoxide (type I mechanism) and singlet oxygen (type II mechanism) that cause massive oxidative damage and consequently the host cell death. Indigofera genus has gained considerable interest due its mutagenic, cytotoxic, and genotoxic activity. Therefore, this study was undertaken to investigate the effect of crude extracts, alkaloidal fraction, and isolated substance derived from Indigofera truxillensis in photodynamic antimicrobial chemotherapy on the viability of bacteria and yeast and evaluation of mechanisms involved. Our results showed that all samples resulted in microbial photoactivation in subinhibitory concentration, with indigo alkaloid presenting a predominant photodynamic action through type I mechanism. The use of CaCl2 and MgCl2 as cell permeabilizing additives also increased gram-negative bacteria susceptibility to indigo.

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Nitric oxide ( NO) is a substance that acts as a second-messenger and is associated with a number of important physiological functions such as regulation of the vascular tonus, immune modulation and neurotransmission. As a physiological mediator, alteration of its concentration level may cause pathophysiological disfunctions such as hypertension, septic shock and impotence. Possible therapeutic approaches are being developed to control NO levels in vivo. We review herein the main physical and chemical properties of NO, its biological functions and available chemical interventions to reduce and increment its physiological concentration levels. Recent developments in the field are also highlighted.

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The extract of stevia leaves (Stevia rebaudiana Bertoni) is the only sweetener utilized in sucrose substitution which can be produced totally in Brazil. The objective of this study, was determine the temporal characteristic of sweet and bitter taste of stevia and compare with sucrose at 3 and 10% in the same equi-sweet. The time-intensity curves (T-I) for each substance were collected through the software Sistema de Coleta de Dados Tempo-Intensidade - SCDTI for Windows, where the judges recorded through of mouse the perception of each stimuli inside function of time, for each sample. The parameters of T-I curves collected were: time for intensity maxim (TImax), intensity maxim (Imax), time of decay (Td), time of plato (Platô), area under curve (Area) and total time of stimuli duration (Ttot). The parameters Td, Ttot, Area e Plato of T-I curves, for stimuli sweet in both sweetness level, were significativelly superior for stevia, while Timax e Imax were significativelly inferior (p£0,05), at differences between value for both substances were superior DESS at 10%. Sucrose didn?t present any record for simuli bitter as 3 as 10%, while stevia presented a characteristic T-I curve with intensity and total time of stimuli duration dependent of concentration.

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Hyaluronic acid is a polysaccharide of the glycosaminoglycan family present in mammal tissues. In the eye, it can be found in the cornea, the sclera and the vitreous humor. Currently, it has been employed in several medical specialties, including ophthalmology. The objective of this paper is to demonstrate the various current and future ophthalmic applications of this substance.

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A case of neuronal ceroid-lipofuscinosis (NCL) is reported in a 11-year-old girl, whose main symptoms were progressive dementia since the age of 4 years and choreic movements since age 10. Seizures, myoclonus and visual deterioration were absent and optic fundi were normal. A cerebral biopsy disclosed two basic types of stored substance in the cytoplasm of neurons: a) severely balloned nerve cells in cortical layers HI and V contained a non-autofluorescent material, which stained with PAS and Sudan Black B in frozen, but not in paraffin sections; ultrastructurally, these neurons showed abundant corpuscles similar to the membranous cytoplasmic bodies of Tay-Sachs disease and, in smaller amounts, also zebra bodies; b) slightly distended or non-distended neurons in all layers contained lipopigment granules, which were autofluorescent, PAS-positive and sudanophil in both frozen and paraffin sections; their ultrastructure was closely comparable to that of lipofuscin. Similar bodies were found in the swollen segments of axons and in a few astrocytes and endothelial cells. The histochemical and ultrastructural demonstration of large amounts of lipopigments allows a presumptive classification of the case as NCL. However, the presence of involuntary movements, the absence of visual disturbances and the unusual ultrastructural features place the patient into a small heterogeneous group within the NCL. A better classification of such unique instances of the disease must await elucidation of the basic enzymatic defects.

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Universidade Estadual de Campinas . Faculdade de Educação Física

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Universidade Estadual de Campinas . Faculdade de Educação Física