Aspectos ultrassonogr��ficos associados �� morbidade de formas cl��nicas cr��nicas de esquistossomose mans��nica, utilizando-se protocolo proposto pela Organização Mundial da Sa��de

OBJETIVO: Avaliar aspectos ultrassonogr��ficos associados �� morbidade em pacientes com formas cl��nicas cr��nicas de esquistossomose mans��nica, utilizando-se protocolo proposto pela Organização Mundial da Sa��de (OMS). MATERIAIS E M��TODOS: Foram avaliadas duas popula����es distintas: a) ��rea end��mica e b) institucional terci��ria, com histopatol��gico confirmando fibrose. Crit��rios de inclus��o: diagn��stico confirmado por parasitol��gico de fezes para Schistosoma mansoni (m��todo Kato-Katz). Crit��rios de exclus��o: sorologia positiva para HIV, HTLV-1, VHB ou VHC. Foi utilizado protocolo ultrassonogr��fico de Niamey, proposto pela OMS. RESULTADOS: Avaliando-se isoladamente as medidas dos espa��os periportais, estas se mostraram sem altera����es em 21% dos indiv��duos com doen��a avan��ada da institui����o terci��ria. Utilizando-se todos os par��metros do protocolo, 100% dos indiv��duos da institui����o terci��ria, com forma grave da doen��a, apresentaram fibrose periportal avan��ada. Em pacientes hepatoespl��nicos da ��rea end��mica n��o se identificou fibrose �� ultrassonografia. CONCLUS��O: O protocolo ultrassonogr��fico proposto pela OMS detecta fibrose periportal avan��ada nos pacientes com forma grave da doen��a, com maior sensibilidade do que a medida do espa��o periportal isoladamente. A complexidade de identifica����o das fases iniciais da fibrose periportal, em ��reas end��micas, pela ultrassonografia, pode suscitar o campo da complementa����o diagn��stica e a continuidade do aprimoramento dos protocolos ultrassonogr��ficos nestas ��reas.

Rela����o entre as massas ��mida, seca e de cinza em materiais biol��gicos - uma ferramenta para amostragens em campo e an��lise de amostras

Little is known about the amount of water and ash in brazilian foodstuffs and plants. The relationships between fresh, dry and ash weight were determined in 40 different biological samples. It could be an important tool when one studies biological material containing low concentration of the chemical elements. This study address to determine these relationships and to provide the amount of biological material that one needs to collect. It aims to supply information that could be used to improve the detection limit, precision and accuracy of the analytical methodology utilized.

Utiliza����o de endoper��xidos de derivados de naftaleno como fontes qu��micas de oxig��nio singlete em sistemas biol��gicos

Molecular oxygen, in the first excited state (singlet oxygen, ��O2), has a substantial reactivity towards electron-rich organic molecules, such as biological targets, including unsaturated fatty acids, proteins, RNA and DNA. Considering the complexity of biological systems and the great variety of reactive species generated by photochemistry, efforts have been devoted to develop suitable ��O2 generators based on the thermolysis of water soluble naphthalene endoperoxides. These compounds are chemically inert and have been employed as versatile sources of ��O2. The synthesis is based on structural modifications in position 1,4 of dimethylnaphtalene, grafting hydrophilic substituents. The correspondent endoperoxide can be generated using photochemical method, or molybdate-catalyzed disproportionation of hydrogen peroxide.

M��todos de extra����o e/ou concentra����o de compostos encontrados em fluidos biol��gicos para posterior determina����o cromatogr��fica

When organic compounds present in biological fluids are analysed by chromatographic methods, it is generally necessary to carry out a prior sample preparation due the high complexity of this type of sample, especially when the compounds to be determinated are found in very low concentrations. This article describes some of the principal methods for sample preparation in analyses of substances present in biological fluids. The methods include liquid-liquid extraction, solid phase extraction, supercritical fluid extraction and extraction using solid and liquid membranes. The advantages and disadvantages of these methods are discussed.

O impacto do cr��mio nos sistemas biol��gicos

The impact of biological chromium's activity may be beneficial or not. This review presents the most relevant chemical aspects of these "two faces" of chromium by covering first, the efforts toward a clearer understanding of the carcinogenic properties of chromium compounds. The biomimetic chemistry of Cr(V) complexes illustrates the interactions of the intermediates formed by Cr(VI) reduction with DNA or oligonucleotides. The importance of trivalent chromium as an essential element is also emphasized by summarizing the recent results of the investigations on trinuclear chromium complexes as models of the cofactor responsible for the insulin activity, as well as good candidates for new nutritional supplements.

As percep����es dos professores de qu��mica geral sobre a sele����o e a organização conceitual em sua disciplina

The teaching of general chemistry involves both the choice and the organization of its concepts. Although College Teachers make their choices, frequently the text books play an important role in this selection. In the present project we intend to show what are Teachers' perceptions of conceptual organization and selection as well as their perceptions of how to teach general chemistry. This demonstration is carried out through the use of metaphors from new information technologies.

G��nero Baccharis (Asteraceae): aspectos qu��micos, econ��micos e biol��gicos

The Baccharis genus is represented by more than 500 species distributed mainly in the tropical areas of South America. Many of them are extensively used in folk medicine in the treatment or prevention of anemias, inflammations, diabetes and stomach, liver and prostate diseases. Phytochemical and biological investigations in about 120 species resulted mainly in the isolation of clerodane and labdane diterpenes and flavonoid aglicones with the flavone unit being the most frequent.

��cidos si��licos: da compreens��o do seu envolvimento em processos biol��gicos ao desenvolvimento de f��rmacos contra o agente etiol��gico da gripe

Sialic acids are nine-carbon carbohydrates that occur widely in nature and occupy the terminal portions of some glycoproteins and glycolipids of cell membranes. These carbohydrates are closely involved in cell-cell interactions and in processes such as microbial infection, inflammation, etc. Studies on the participation of sialic acids in biological processes have provided comprehension about their role in the infection by the influenza virus, the causal agent of flu. In this article, we present an overview of the importance of sialic acids in the influenza virus infection and how the knowledge of their involvement in this process has allowed the development of selective and efficient drugs against the virus.

Contribui����o �� organização da pesquisa em Qu��mica e os desafios da intera����o com outras ��reas do conhecimento

This article provides some aspects that allow making a current reading of the situation of the Brazilian Chemistry that permit us considerate it as a strategic area. They are still presented some initial proposals related to the organization of the research as well as to win the challenges of the relationship with the other areas of the knowledge.

Interfaces e organização da pesquisa no Brasil: da Qu��mica �� Nanotecnologia

Nanotechnology can be viewed as a powerful tool, capable of shaping the chemistry of atoms and molecules, converting them into exciting nanosized and nanostructured materials, devices and machines. However, in pursuing this task, an exceptional ability is required to deal with complex inter- and multidisciplinary approaches, as imposed by the nanoscale. A new research organization framework, capable of promoting cooperative interactions in many complementary areas, including the industries, is demanded. In this sense, an interesting example are the nanotechnology networks and millenium institutes recently created in Brazil. The highlights and weakness of such cooperative research networks are discussed, in addition to relevant nanotechnology themes focusing on the special needs and resources from the developing nations.

Organização de pesquisa no Brasil: li����es do passado, propostas para o futuro

Chemical research in Brazil has grown significantly in the past 20 years, largely thanks to the Brazilian S&T Development Program of the federal government (PADCT). However, the newly achieved levels of highly qualified manpower and research infra-structure require new research organization frameworks to make science, technology and innovation really useful and meaningful for the citizens. The current requirements for creating viable networks of academic and industry researchers are presented and discussed as well as some structural and procedural bottlenecks that have to be eliminated, to achieve maximum high-quality science, technology and relevant innovation output.

Aspectos f��sico-qu��micos e biol��gicos relacionados �� ocorr��ncia de Biomphalaria glabrata em focos litor��neos da esquistossomose em Pernambuco

This study analyzes the physico-chemical and biological parameters of freshwater aquatic environments in coastal areas of the State of Pernambuco, Brazil, where snail vector foci and cases of schistosomiasis have been recorded. The tests were carried out using standard methods and sediments were analyzed using the X-ray fluorescence technique. The micro-algae were analyzed using conventional microscopy. The most abundant chemical elements in the sediments were Fe, Ca, Si and Al and there were high concentrations of electrolytes in comparison with data published in the literature. The mean values for salinity (7.7 g/L) and sulfate (489 mg/L) were much higher than normal for freshwater environments. The micro-algae identified are those that inhabit environments with higher levels of salinity. The snail Biomphalaria glabrata seems, therefore, to be more tolerant to salty environments and this constitutes a risk of spread of schistosomiasis.

Aspectos qu��micos, biol��gicos e etnofarmacol��gicos do g��nero Cassia

Species of Cassia are widely distributed in tropical and subtropical regions throughout the world, and have been extensively investigated chemically and pharmacologically.They are known to be a rich source of phenolic derivatives, most of them with important biological and pharmacological properties. Some Asian, African and Indian tribes use these species as a laxative, purgative, antimicrobial, antipyretic, antiviral and anti-inflammatory agent. Among a number of other classes of secondary metabolites, such as anthracene derivatives, antraquinones, steroids and stilbenoids, biologically active piperidine alkaloids are an especially important bioactive class of compounds that showed to be restricted to a small group of Cassia species. In this paper we present an overview of the chemical, biological and ethnopharmacological data on Cassia piblished in the literature.

Microextra����o em fase l��quida (LPME): fundamentos da t��cnica e aplica����es na an��lise de f��rmacos em fluidos biol��gicos

The analysis of drugs and metabolites in biological fluids usually requires extraction procedures to achieve sample clean-up and analyte preconcentration. Commonly, extraction procedures are performed using liquid-liquid extraction or solid-phase extraction. Nevertheless, these extraction techniques are considered to be time-consuming and require a large amount of organic solvents. On this basis, microextraction techniques have been developed. Among them, liquid-phase microextraction has been standing out. This review describes the liquid-phase microextraction technique based on hollow fibers as a novel and promising alternative in sample preparation prior to chromatographic or electrophoretic analysis. The basic concepts related to this technique and its applicability in extraction of drugs are discussed.

Determina����o voltam��trica de metais em ��guas e fluidos biol��gicos empregando mineraliza����o de amostras com radia����o ultravioleta

This work describes the optimization of pretreatment steps for the destruction of organic matter in samples of waters and biological fluids, by using an UV irradiation system with a high power UV radiation source (400 W). The efficiency of the system constructed for the photo-decomposition of samples of model waters, natural waters and biological fluids was investigated by performing recovery experiments of the metallic species Zn(II), Cd(II), Pb(II), Cu(II), Al(III) and Fe(III). The use of UV irradiation allowed the liberation of metals bound to the organic matrix and the determination of the total content of elements in the samples.