RESUMO Considerando que, entre todas as fontes de erro analítico, a hemólise é a mais importante na rotina laboratorial, o presente estudo teve como objetivo investigar o efeito da hemólise in vitro sobre os principais biomarcadores plasmáticos de estresse oxidativo mensurados (BPEO) de cães. Para tal, amostras de sangue total de 19 cães clinicamente saudáveis foram hemolisadas em diferentes graus por ação mecânica. Amostras controle contendo baixa concentração de hemoglobina (Hb) no plasma foram comparadas com quatro graus de hemólise (<0,36; 0,36-0,60; 0,61-1,0; 1,1-4g/L Hb). Imediatamente após a hemólise, foram mensuradas as concentrações plasmáticas de ácido úrico (AU), albumina, bilirrubina, gamaglutamiltransferase (GGT), capacidade antioxidante total (TAC) e concentração de oxidante total (TOC). Os erros relativos causados pelos diferentes graus de hemólises foram calculados e confrontados com o erro total aceitável (ETA) e com o limite de erro permitido (LEP) empregados nos programas de controle de qualidade de exames laboratoriais. Foi observado que mesmo pequeno grau de hemólise gera algum erro analítico não aceitável (ETA e/ou LEP) nos BPEO mensurados, exceto na bilirrubina. Foi possível concluir que a hemólise é um fator limitante para avaliação do estresse oxidativo sistêmico mensurado no plasma, podendo causar erros que potencialmente comprometem o diagnóstico clínico.

ABSTRACT Among all the various sources of analytical error, hemolysis is the most important in the laboratory routine. The present study aimed to investigate the effect of hemolysis "in vitro" on the main plasma biomarkers of oxidative stress (BPEO) dogs. For this purpose, whole blood samples from 19 healthy dogs were hemolyzed in different degrees by mechanical action. Control samples containing low concentration of hemoglobin (Hb) levels in plasma were compared with four degrees of hemolysis (<0.36, from 0.36 to 0.60, 0.61 to 1.0, 1.1 to 4g/L Hb). Immediately after causing hemolysis, plasma concentrations of uric acid (UA), albumin, bilirubin, gamma glutamyl transferase (GGT), total antioxidant capacity (TAC), and total oxidant concentration (TOC) were measured. The relative errors caused by several levels of hemolysis were calculated and compared with the total acceptable error (TAE) and allowed error limit (LEP) by employees in quality control programs for laboratory tests. Even small levels of hemolysis generate unacceptable analytical error (TAE and / or LEP) in BPEO measured, except for bilirubin. Hemolysis is a limiting factor for the assessment of systemic oxidative stress measured in plasma and may cause errors that potentially compromise clinical diagnosis.

Resumo O conhecimento local acerca da biodiversidade vem sendo utilizado em pesquisas voltadas ao uso e manejo de recursos naturais aliados à conservação. Entre estes recursos, destaca-se o Pequi (Caryocar brasiliense Cambess.) devido à sua importância econômica e alimentar para comunidades que vivem no Cerrado. No quilombo de Pontinha, localizado na região central do estado de Minas Gerais, um estudo etnoecológico sobre o Pequi foi desenvolvido, a fim de subsidiar iniciativas de geração de trabalho e renda para esta comunidade. Informações foram obtidas por meio de entrevistas semiestruturadas, observação participante e travessia. Alimentação familiar (97%), produção de sabão (67%), produção de óleo (37%), tratamento medicinal (17%) e comércio (3%) foram os principais usos do Pequi citados pelos comunitários. Abelhas foram os visitantes florais com maior Índice de Saliência (S=0,639). Dentre os frugívoros que se alimentam de frutos não caídos, as aves apresentaram maior Saliência (S=0,359) e os insetos foram os mais importantes frugívoros entre os que utilizam frutos caídos (S=0,574). Brocas, lagartas folívoras e que atacam troncos e raízes foram as pragas mais citadas. Os indivíduos jovens de Pequi são, segundo os entrevistados, os mais afetados pelo fogo devido ao menor porte e por ter a casca menos espessa. O reconhecimento da importância cultural e ecológica do Pequi tem mobilizado a comunidade, que demonstra interesse em fazer dessa espécie uma alternativa de renda.

Abstract Local knowledge of biodiversity has been applied in support of research focused on utilizing and management of natural resources and promotion of conservation. Among these resources, Pequi (Caryocar brasiliense Cambess.) is important as a source of income and food for communities living in the Cerrado biome. In Pontinha, a “quilombola” community, which is located in the central region of State of Minas Gerais, Brazil, an ethnoecological study about Pequi was conducted to support initiatives for generating income for this community. Data were collected through semi-structured interviews, participant observation, and crossing. The most relevant uses of Pequi were family food (97%), soap production (67%), oil production (37%), medical treatments (17%), and trade (3%). Bees were the floral visitors with the highest Salience Index (S=0.639). Among frugivores that feed on unfallen fruits, birds showed a higher Salience (S=0.359) and among frugivores who use fallen fruits insects were the most important (S=0.574). Borers (folivorous caterpillars) that attack trunks and roots were the most common pests cited. According to the respondents, young individuals of Pequi are the most affected by fire due to their smaller size and thinner bark. Recognition of the cultural and ecological importance of Pequi has mobilized the community, which has shown interest in incorporating this species as an alternative source of income.

Objective. We analyze the most suitable time to perform tracheostomy in neurocritically ill patients. We compare morbimortality and use of resources between those patients in which tracheostomy was done early (< 9 days) and those in which it was perform later (>9 days), in a selected group of patients. Material and methods. We made an observational prospective study involving a group of patients diagnosed as traumatic brain injury (TBI) or stroke, whose tracheostomy was performed during their stay at the Intensive Care Unit. We compared two groups: a) early tracheostomy (during first 9 days of ICU stay); b) late tracheostomy (made on 10th day or later). As variables, we studied: demographic data, severity of illness at admission, admittance department, diagnosis, length of intubation, length of mechanical ventilation (LMV), sedation and antibiotic treatment needs, ventilatorassociated pneumonia (VAP) events, ICU length of stay and mortality. We calculated relative risk of suffering from pneumonia and made a multivariate logistic regression to establish which factors were associated with an increased risk of developing pneumonia. Statistical signification p < 0.05. Results. We analyzed 118 patients, 60% with TBI. Mean length of intubation before tracheostomy was 12 days and mean LMV was 20 days. 94 VAP events were diagnosed in 81 patients (68.6%). Early tracheostomy group showed lower length of mechanical ventilation and ICU stay, lower length of sedation and antibiotic treatment, and less pneumonia events (p<0,001). The precocity of tracheostomy didn't have any influence either on hospital length of stay (p=0.844), ICU mortality (p=0.924) or in-hospital mortality (p=0.754). At the TBI group mean age was lower (p<0.001), tracheostomy was made later (p=0.026), and patients needed a longer sedation (p=0.001) and a longer antibiotic treatment (p=0.002). Length of intubation (p=0.034, OR 1.177) and ICU length of stay (p=0.003, OR 1.100) were factors independently associated with development of pneumonia. Relative risk of suffering from pneumonia when tracheostomy was made after 9 days of ICU stay was 1.55 (IC 95%: 1.10-2.16). The number needed to treat (NNT) for early tracheostomy avoiding one pneumonia event was 3.13. VAP was not associated with a higher ICU (p=0.558) or in-hospital mortality (p=0.370). Conclusions. Early tracheostomy (<9 days) provides significant advantages in neurocritically ill patients: it shortens length of mechanical ventilation and ICU stay and decreases antibiotic and sedatives requirements. Although later tracheostomy is not directly related with mortality, it increases considerably the risk of suffering from pneumonia, particularly in patients with TBI. These clinical circumstances should be evaluated individually in each patient, so the best time to perform tracheostomy in neurocritically ill patients could be established.

Objetivos. Analizar el momento más adecuado para la realización de la traqueotomía en enfermos neurocríticos, comparando en una población seleccionada de pacientes las diferencias de morbimortalidad y consumo de recursos entre el grupo en que se realizó la traqueotomía precozmente (<9 días) y aquéllos en los que fue más tardía (>9 días). Material y métodos. Estudio prospectivo y observacional en una población de pacientes con diagnóstico de traumatismo craneoencefálico (TCE) o accidente cerebrovascular (ACVA) que precisaron traqueotomía durante su ingreso en UCI. Se compararon los datos en dos grupos de pacientes: a) traqueotomía precoz (TP) en los primeros 9 días; b) traqueotomía tardía (TT) a partir del 10º día. Variables estudiadas: datos demográficos, gravedad al ingreso, procedencia, diagnóstico, duración de la intubación orotraqueal (IOT) y de la ventilación mecánica (VM), necesidades de sedación y de antibioterapia, frecuencia de neumonía asociada a ventilación mecánica (NAV), duración de la estancia y mortalidad. Se calculó el riesgo relativo de padecer neumonía y un modelo de regresión logística multivariante para determinar los factores asociados al desarrollo de neumonía. Significación estadística para una p<0.05. Resultados. Se estudiaron 118 pacientes, 60% con TCE. La media de IOT previa a la traqueotomía (TRQ) fue de 12 días y la duración de la VM de 20 días. Se diagnosticaron 94 episodios de NAV en 81 pacientes (68.6%). El grupo de TP muestra menor duración de la VM, de la sedación, de la antibioterapia y de la estancia en UCI, con menor incidencia de neumonía (p<0.001). La precocidad de la TRQ no influyó en la duración de la estancia hospitalaria (p=0.844), ni en la mortalidad en UCI (p=0.924), ni en la hospitalaria (p=0.754). La media de edad fue menor en el grupo con TCE (p<0.001), además la TRQ se realiza más tarde (p=0.026) y requieren más días de sedación (p=0.001) y de tratamiento antibiótico (p=0.002). Los factores independientemente asociados con el desarrollo de neumonía fueron los días de IOT (p=0.034, OR 1.177) y los días de estancia en UCI (p=0.003, OR 1.100). El riesgo relativo de padecer neumonía si la TRQ se realiza después de 9 días es 1.55 mayor (IC 95%: 1.10-2.16). Número necesario de pacientes a tratar (NNT) para que la TRQ precoz evite un episodio de neumonía: 3.13. La presencia de NAV no se asocia con una mayor mortalidad en UCI (p=0.558) ni hospitalaria (p=0.370). Conclusiones. La traqueotomía precoz (<9 días) en los enfermos neurocríticos aporta ventajas apreciables, acortando los días de ventilación mecánica y de estancia en UCI, con menores requerimientos de sedación y de antibioterapia. Aunque la TRQ más tardía no se relaciona directamente con la mortalidad, se eleva considerablemente el riesgo de padecer neumonía, de manera especial en pacientes con TCE. Estas circunstancias clínicas deben valorarse individualmente en cada caso a fin de establecer el momento más adecuado para practicar la TRQ en los pacientes neurocríticos.

A falha ou perda da eficácia relativa dos resíduos culturais compromete o controle da erosão hídrica por meio da cobertura do solo em sistemas conservacionistas de preparo do solo. Com o objetivo de investigar a falha de resíduos culturais em diferentes situações no sistema de semeadura direta, foi instalado um experimento na Estação Experimental Agronômica da UFRGS, em Eldorado do Sul (RS), sobre um Argissolo Vermelho distrófico típico com 0,105 m m-1 de declividade média. Os tratamentos consistiram de resíduos recém-colhidos de aveia preta (out/97) e soja (maio/98) e resíduos semidecompostos de milho e soja (150 e 175 dias após a colheita, out/97 e 98, respectivamente), em diferentes quantidades e formas de manejo. Aplicou-se chuva simulada nas parcelas experimentais com intensidade constante de 63,5 mm h-1, até obtenção da taxa constante de enxurrada e, então, iniciou-se, concomitantemente à aplicação de chuva, a adição de fluxos extras de água limpa na cabeceira das parcelas, para simular comprimentos de rampa mais longos. Os dez níveis de fluxos extras de água planejados variaram de 16 a 197 (10-5) m³ s-1 m-1, com duração de 7 min cada nível. A falha do resíduo foi identificada e o equivalente comprimento crítico de rampa calculado, a partir da observação visual no campo e do uso de critério teórico baseado na relação da taxa de erosão com a taxa de descarga da enxurrada. Os intervalos de ocorrência dos comprimentos críticos de rampa obtidos variaram de 29-58 m (3.950 kg ha-1 de resíduos semidecompostos de soja, soltos) a 152-164 m (6.200 kg ha-1 de resíduos semidecompostos de milho, semi-ancorados). No tratamento com 5.600 kg ha-1 de resíduos de aveia preta, semi-ancorados, não foi observada falha do resíduo. Os resultados comprovaram que existem limites de comprimento de rampa no sistema de semeadura direta, dependendo do regime de chuva, solo, declividade e condições de manejo.

Erosion control benefits provided by conservation tillage can be diminished if mulch fails or loses its effectiveness. A field experiment was carried out at the Agriculture Experimental Station of the Federal University of Rio Grande do Sul in Eldorado do Sul, RGS, Brazil, on a 0.105 m m-1 slope, sandy loam Ultisol, to investigate mulch failure for different forms of residue management under no-till system. Simulated rainfall (63.5 mm h-1) was applied with the rotating-boom rainfall simulator until steady-runoff rates were obtained, when extra-inflow consisting of clear water was added at the upper end of the plots to simulate longer slope lengths. Ten-levels of extra-inflow ranged from 16 to 197 (10-5) m³ s-1 m-1, with a duration of 7-min each. Treatments consisted of fresh oat (Oct/97) and soybean (May/98) residues, and semi-decomposed corn and soybean residues (150 and 175 days after harvesting, Oct/97-98, respectively), in different rates and management forms. Mulch failure was identified, and critical slope lengths calculated, using visual observations in the field and a theoretical criterion, based on the relationship between erosion and discharge rates at the midpoint of the plot. Calculated, critical slope-length intervals ranged from 29-58 m (3,950 kg ha-1 of unanchored, semi-decomposed soybean residue) to 152-164 m (6,200 kg ha-1 of semi-anchored, semi-decomposed corn residue). There was no evidence of mulch failure for the 5,600 kg ha-1 semi-anchored oat residue treatment. The results proved that slope-length limits may exist under no-till system, and that mulch failure criteria can be helpful for a better RUSLE's C-factor evaluation, as well as for determining terrace spacing in this system, resulting in its increased effectiveness for erosion control. Critical slope lengths, however, will vary with rainfall, soil, slope, and management decisions.