Performance of the 13C-urea breath test for the diagnosis of H. pylori infection using a substrate synthesized in Brazil: A preliminary study

OBJECTIVE: The 13C-urea breath test is the main non-invasive test for the diagnosis of Helicobacter pylori infection. The availability of this test throughout the country is limited, mainly due to the difficulty in obtaining the labeled isotope from abroad. Recently, researchers from the Nuclear Energy Center in Agriculture at the University of São Paulo (CENA/USP) succeeded in synthesizing 13C-enriched urea for Helicobacter pylori diagnosis. The aim of the study was to compare the performance of the 13C-urea breath test using 13C-urea acquired abroad with that of a test using 13C-urea synthesized in Brazil. METHOD: Sixty-four dyspeptic patients participated in the study (24 men and 40 women). Initially, the patients performed the 13C-urea breath test using the imported substrate (Euriso-Top, France). Seven to fourteen days later, all the patients repeated the test using the Brazilian substrate. The samples from both examinations were processed in an infrared isotope analyzer (IRIS, Wagner Analisen Technik, Germany), and all delta over baseline (DOB) [%] values above four were considered positive results. RESULTS: Twenty-seven patients (42%) exhibited negative results for Helicobacter pylori infection, and thirty-seven patients (58%) exhibited positive results when tested using the foreign substrate (gold standard). There was a 100% concordance regarding the presence or absence of infection when the gold standard results were compared with those obtained using the Brazilian substrate. CONCLUSIONS: Similar performance in the diagnosis of Helicobacter pylori infection was demonstrated when using the 13C-urea breath test with the Brazilian 13C-urea substrate and the test with the substrate produced abroad. This validation represents an important step toward increasing the availability of the 13C-urea breath test throughout the country, which will have a positive influence on the management of Helicobacter pylori infection.

Dinâmica do ecótono floresta-campo no sul do estado do Amazonas no Holoceno, através de estudos isotópicos e fitossociológicos / Vegetation dynamics during the Holocene in a forest-savanna transition, Southern Amazon Basin, based on isotope and phytosociological studies

Com o emprego dos isótopos do carbono (12C, 13C, 14C) da matéria orgânica do solo (MOS) e das plantas, é apresentado um estudo comparativo entre perfis orgânicos de solos formados em depressões de áreas cobertas por ecossistemas de campos e florestas ao sul do estado do Amazonas, visando o entendimento da dinâmica da paleovegetação. A dinâmica da vegetação atual na região foi avaliada utilizando-se estudos fitossociológicos e caracterizações botânica e isotópica (delta13C) das espécies de plantas presentes em duas bordas floresta-campo. Teores de carbono orgânico total foram superiores nas camadas superficiais no campo, quando comparados com a floresta. Dados de delta13C associados à cronologia do 14C indicaram predomínio de plantas C3 no início do Holoceno em ambos os ecótonos. Entre aproximadamente 7.000-3.000 anos AP verificou-se a influência crescente de plantas C4, indicando regressão da floresta com possível presença de um clima mais seco. A partir de aproximadamente 3.000 anos AP os dados sugeriram expansão da floresta provavelmente relacionada ao retorno a um clima mais úmido. A presença de algumas espécies características da borda, como a Sclerolobium paniculatum e Himatanthus sucuuba, nos campos, sugere o atual avanço da floresta sobre os mesmos. Estas espécies estariam sendo as bioindicadoras desse avanço.

This paper presents a comparative study between organic soil horizons formed in depressions located at the forest/savanna boundary in the Southern Amazon Basin. The influence of the paleovegetation dynamics, based on carbon isotope (12C, 13C and 14C) data of soil organic matter (SOM) and plants was evaluated, as well as the present vegetation dynamics, inferred from the modern vegetation structure, composition and phytosociology. The uppermost soil horizon in savanna showed higher total carbon content than in forest. 13C and 14C data from soil samples indicated a predominance of C3 plants in the early Holocene. About 7000 to 3000 14C yr BP the influence of C4 plants increased, indicating savanna expansion probably related to a drier climate in the region. Since approximately 3000 14C yr BP, the carbon isotope data suggest the expansion of forest probably due to a wetter climate. The presence of typical boundary plant species (Sclerolobium paniculatum and Himatanthus sucuuba) in the savanna also suggested present forest expansion.

Implantação de Programas de Gerenciamento de Resíduos Químicos Laboratoriais em universidades: análise crítica e recomendações / Establishment of Laboratory Waste Management Programs in universities: critical review and recommendations

Programas de Gerenciamento de Resíduos Químicos Laboratoriais vêm sendo implantados em várias universidades do país e do mundo, em reconhecimento à necessidade premente de alterar a realidade de descaso para com o ambiente, associado à responsabilidade objetiva do gerador e, principalmente, à consciência de sustentabilidade, em consonância com a Agenda 21. Neste contexto, o presente trabalho relata essa problemática de forma a reunir uma série de informações por meio de revisão da literatura recente, desenvolvendo uma análise crítica e desmistificando alguns (pré) conceitos através de um questionário aplicado aos pesquisadores atuantes nesta área de conhecimento. Esse estudo permitiu, por fim, a proposição de regras básicas a serem adotadas na implementação de um programa de gerenciamento de resíduos laboratoriais.

Laboratory Waste Management Programs have been established in several universities all over the world. These programs are important because they provide the understanding and protection of the environment, encouraging the waste generator's responsibility and, mainly, accomplishing sustainable practice in the laboratory, in accordance with the Agenda 21. In this context, based on a literature review, the present work discusses the subject, introducing some recommendations to be applied in universities. A questionnaire applied to researchers of this area shows important information about the start of the programs, mainly difficulties, among other cares. This study allowed the proposition of basic rules about the establishment of laboratory waste management.