Efeito da hipóxia e reoxigenação na resposta à angiotensina II em células mesangiais in vitro

INTRODUCTION: Mesangial cells (MC) may be involved in the glomerular alterations induced by ischemia/reperfusion injury. OBJECTIVE: To evaluate the response of immortalized MC (IMC) to 30 minutes of hypoxia followed by reoxygenation periods of 30 minutes (H/R30) or 24 hours (H/R24). METHODS: The intracellular calcium concentration ([Ca+2]i) was measured before (baseline) and after adding angiotensin II (AII, 10-5 M) in the presence and absence of glybenclamide (K ATP channel blocker). We estimated the level of intracellular ATP, nitric oxide (NO) and PGE2. RESULTS: ATP concentration decreased after hypoxia and increased after reoxygenation. Hypoxia and H/R induced increases in basal [Ca+2]i. AII induced increases in [Ca+2]i in normoxia (97 ± 9%), hypoxia (72 ± 10%) or HR30 (85 ± 17%) groups, but there was a decrease in the response to AII in group H/R24 since the elevation in [Ca+2]i was significantly lower than in control (61 ± 10%, p < 0.05). Glybenclamide did not modify this response. It was observed a significant increase in NO generation after 24 hours of reoxygenation, but no difference in PGE2 production was observed. Data suggest that H/R injury is characterized by increased basal [Ca+2]i and by an impairment in the response of cells to AII. Results suggest that the relative insensibility to AII may be at least in part mediated by NO but not by prostaglandins or vasodilator K ATP channels. CONCLUSION: H/R caused dysfunction in IMC characterized by increases in basal [Ca+2]i during hypoxia and reduction in the functional response to AII during reoxygenation.INTRODUÇÃO: Células mesangiais (CM) podem estar envolvidas na lesão glomerular induzida por hipoxia/reperfusão (H/R). OBJETIVO: Avaliar a resposta de CM imortalizadas (CMI) à hipoxia por 30 minutos seguida de reoxigenação por 30 minutos (H/R30) ou 24 horas (H/R24). MÉTODOS: Concentração de cálcio intracelular ([Ca+2]i) foi avaliada antes (basal) e após a adição de angiotensina II (AII, 10-5 M), na presença e na ausência de glibenclamida (bloqueador de canais K ATP). Foram estimados o nível de ATP intracelular, de óxido nítrico (NO) e de PGE2. RESULTADOS: Nível de ATP diminuiu após hipóxia e aumentou após a reoxigenação. H/R induziu aumento na [Ca+2]i basal. A AII elevou a [Ca+2]i nas condições de normoxia (97 ± 9%), hipoxia (72 ± 10%) ou HR30 (85 ± 17%), porém no grupo H/R24, houve diminuição significativa na resposta à AII, uma vez que a elevação da [Ca+2]i foi mais baixa do que no controle (61 ± 10%, p < 0,05). Glibenclamida não alterou esta resposta. Houve um aumento significativo na geração de NO após 24 horas de reoxigenação, mas não foi observada nenhuma diferença na produção de PGE2. Os dados indicam que a injuria celular causada pela hipoxia/reoxigenação é caracterizada pelo aumento na [Ca+2]i basal e por uma diminuição na reatividade celular à AII. Resultados sugerem que a insensibilidade ao agonista constritor pode ser pelo menos em parte, mediada pelo NO, mas não pelas prostaglandinas ou por canais K ATP. CONCLUSÃO: H/R resultou em disfunção das CMI, caracterizada pelo aumento na [Ca+2]i basal durante a hipóxia e redução da resposta funcional a AII durante a reoxigenação.Federal University of São PauloUNIFESPSciEL

Effect of an isotonic rehydration sports drink and exercise on urolithiasis in rats

The objective of the present study was to evaluate the role of physical exercise as well as the influence of hydration with an isotonic sports drink on renal function in male Wistar rats. Four groups were studied over a period of 42 days: 1) control (N = 9); 2) physical exercise (Exe, N = 7); 3) isotonic drink (Drink, N = 8); 4) physical exercise + isotonic drink (Exe + Drink, N = 8). Physical exercise consisted of running on a motor-driven treadmill for 1 h/day, at 20 m/min, 5 days a week. The isotonic sports drink was a commercial solution used by athletes for rehydration after physical activity, 2 ml administered by gavage twice a day. Urine cultures were performed in all animals. Twenty-four-hour urine samples were collected in metabolic cages at the beginning and at the end of the protocol period. Urinary and plasma parameters (sodium, potassium, urea, creatinine, calcium) did not differ among groups. However, an amorphous material was observed in the bladders of animals in the Exe + Drink and Drink groups. Characterization of the material by Western blot revealed the presence of Tamm-Horsfall protein and angiotensin converting enzyme. Physical exercise and the isotonic drink did not change the plasma or urinary parameters measured. However, the isotonic drink induced the formation of intravesical matrix, suggesting a potential lithogenic risk.Universidade Federal de São Paulo (UNIFESP) Departamento de Medicina Disciplina de NefrologiaUniversidade Federal de São Paulo (UNIFESP) Departamento de Farmacologia Disciplina de Fisiologia Cardiovascular e RespiratóriaUNIFESP, Depto. de Medicina Disciplina de NefrologiaUNIFESP, Depto. de Farmacologia Disciplina de Fisiologia Cardiovascular e RespiratóriaSciEL

Effect of vitamin D3 overdose and calcium supplementation in experimental nephrolithiasis model

Introduction:There is little information in the literature relating supplementary oral usage of vitamin D and calcium to the development of kidney stones. Objective:To evaluate the effect of high dose, 200 IU of vitamin D3 (V) with calcium supplementation (Ca). Methods:Experimental model consists of insertion of pellets into the bladder of rats. V was administered for 30 days with or without Ca. The rats were divided in 6 groups: 1. Sham, 2. Pellets control; 3. V control; 4. Pellets + V; 5. Pellets + Ca and 6. Pellets + Ca + V. Results:50% and 17% decreases bladder stones formation in groups 5 and 6, p < 0.005 comparing with the group 2 were observed. There was no hypercalcemia or hypercalciuria in all groups. We observed a significant decrease in calciuria in group 6 (p = 0.03). Conclusion:The administration of the V associated with Ca significantly decreased the formation of stones and caused a significant reduction in urinary calcium, suggesting a protection in the lithogenic pathophysiology.Introdução:Há poucos dados na literatura sobre a suplementação de vitamina D e cálcio e o desenvolvimento de cálculos renais. Objetivo:Avaliar o efeito de doses elevadas de vitamina D3 (V), com suplemento de cálcio (Ca) no desenvolvimento de litíase em modelo experimental. Métodos:Pastilhas foram inseridas na bexiga de ratos, que receberam V com ou sem Ca. Ratos foram divididos em seis grupos: 1. Sham; 2. Controle com pastilha, 3. Controle com V, 4. Pastilha + V, 5. Pastilha + Ca e 6. Pastilha + Ca + V. Resultados:Observou-se 50% e 17% de redução na formação de cálculos, respectivamente nos grupos 5 e 6 em comparação ao grupo 2 (p < 0,005). Não foram observadas hipercalcemia ou hipercalciúria em todos os grupos. Encontramos no grupo 6 (p = 0,03) uma redução significativa na calciúria. Conclusão:A administração de V associada com Ca diminuiu significantemente a formação de cálculos e reduziu significantemente a calciúria, sugerindo uma interferência benéfica na fisiopatologia litogênica.Universidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

Transport system validation and analysis of biological samples sent to a central laboratory

The results obtained from biological sample analysis may be affected by several factors, among them, the conditions of samples transportation from the site of collection to the central laboratory.The aim of this paper was to verify the stability of the samples submitted to the transportation process (from Jundiaí to São Paulo) by comparing the results of 29 clinical laboratory parameters (including microbiology tests) on the same samples submitted or not to transportation. First, we verified the temperature inside a transportation box, during the routine the from Jundiaí to São Paulo, by introducing a special chip able to register it continuously. We observed that the temperature inside the box was kept between 13ºC and 23ºC (similar to room temperature). After that, samples were collected in Jundiaí and divided in two aliquots; one to be analysed at the laboratory in São Paulo. The methodology, apparatus and reagents used on the samples analysis were the same at both laboratories. The statistical analysis showed concordance between both averages trough correlation coefficient intra-class and by the Blan-Altman methods. It was observed that among the 29 parameters: 23 (79,3%) showed good to excellent. On the data from urinalysis we observed a good to excellent concordance in the urocult (88.0%), and as well in the urine I analysis. The data obtained by the correlation between the laboratory results and the graphics of temperature registered by chip are strong indicative of validation of our laboratorial analysis and transportation system, up to 16 hours sample collection.A monitoração de vários interferentes nos resultados das análises clínicas laboratoriais originados do sistema de transporte de amostras biológicas de um posto de coleta para o local da fase analítica propriamente dita é de extrema importância. Com o objetivo de avaliar a estabilidade dos bioanalitos durante o transporte, os autores, neste trabalho, monitoraram a temperatura das caixas térmicas. Através de dispositivos medidores de temperatura (chips) introduzidos no interior de cada caixa térmica, observou-se que elas permaneceram climatizadas em torno de 13º a 23ºC, simulando a temperatura ambiente por todo o percurso e tempo necessários. Compararam-se os resultados de análises clínicas laboratoriais das amostras biológicas sem transporte realizadas no laboratório de origem da coleta (Jundiaí) com os das mesmas amostras biológicas com transporte realizado na central em São Paulo. Inicialmente foram estudados os principais parâmetros bioquímicos e a coagulação do sangue, além da urinálise com bacteriologia. A análise estatística foi de concordância entre as duas médias através do coeficiente de correlação intraclasse e também pela técnica de Bland-Altman, na qual se observou que, entre os 29 analíticos estudados, 23 (79,3%) apresentaram concordância boa a excelente; cinco (17,2%), moderada a boa; e uma (3,5%), fraca a moderada. Quanto às uroculturas, elas apresentaram 88% de concordância, portanto boa a excelente, e a urina I apresentou 94% de concordância na hematúria e 87,5% na leucocitúria, também boa a excelente. Os dados obtidos pelas correlações dos resultados das amostras e dos gráficos de temperatura emitidos pelos dispositivos registradores representaram indicadores de validação do sistema de transporte e das análises laboratoriais em até 16 horas após coleta do material, simulando um posto muito distante.Universidade Federal de São Paulo (UNIFESP)AFIP Medicina LaboratorialUniversidade de São PauloAFIP Medicina Laboratorial setor de BacteriologiaAFIP Medicina Laboratorial setor de BioquímicaUNIFESP Departamento de PsicobiologiaUNIFESP, Depto. de PsicobiologiaSciEL

Receptor-Induced Dilatation in the Systemic and Intrarenal Adaptation to Pregnancy in Rats

Normal pregnancy is associated with systemic and intrarenal vasodilatation resulting in an increased glomerular filtration rate. This adaptive response occurs in spite of elevated circulating levels of angiotensin II (Ang II). In the present study, we evaluated the potential mechanisms responsible for this adaptation. The reactivity of the mesangial cells (MCs) cultured from 14-day-pregnant rats to Ang II was measured through changes in the intracellular calcium concentration ([Cai]). The expression levels of inducible nitric oxide synthase (iNOS), the Ang II-induced vasodilatation receptor AT2, and the relaxin (LGR7) receptor were evaluated in cultured MCs and in the aorta, renal artery and kidney cortex by real time-PCR. The intrarenal distribution of LGR7 was further analyzed by immunohistochemistry. The MCs displayed a relative insensitivity to Ang II, which was paralleled by an impressive increase in the expression level of iNOS, AT2 and LGR7. These results suggest that the MCs also adapt to the pregnancy, thereby contributing to the maintenance of the glomerular surface area even in the presence of high levels of Ang II. The mRNA expression levels of AT2 and LGR7 also increased in the aorta, renal artery and kidney of the pregnant animals, whereas the expression of the AT1 did not significantly change. This further suggests a role of these vasodilatation-induced receptors in the systemic and intrarenal adaptation during pregnancy. LGR7 was localized in the glomeruli and on the apical membrane of the tubular cells, with stronger labeling in the kidneys of pregnant rats. These results suggest a role of iNOS, AT2, and LGR7 in the systemic vasodilatation and intrarenal adaptation to pregnancy and also suggest a pivotal role for relaxin in the tubular function during gestation

The grotesque universe in Dostoyevskys An Unpleasant Anecdot

Esta pesquisa é composta de uma tradução do original em russo da novela Uma anedota desagradável, de Fiódor Dostoiévski, publicada em 1862 na revista Vriêmia, seguida de um breve comentário sobre ela. Para o estudo do texto considerou-se que seu tema está relacionado com artigos publicados pelo escritor, em que ele expõe as suas observações acerca da intelliguentsia e da sociedade russa da época. No que se refere ao tratamento dado ao tema, o escritor empregou amplamente recursos associados ao universo grotesco, como o riso e a paródia, tanto para a descrição das personagens como para a narração dos acontecimentos.This research is composed of a translation from the Russian novella An unpleasant anecdot, by Fyodor Dostoyevsky, published in 1862 in the periodic Vriemia, followed by a brief commentary about the periodic. To the study of the text was considered that the theme is related to the articles published by the author, on which he exposes his observations about the intelliguentsia and the Russian society of that time. Regarding the treatment given to the theme, the writer largely used resources associated to the grotesque universe, like the laughter and the parody, as to the description of the characters as well as to the narration of the events

Hypoxic injury increases the sensitivity of the mesangial cells to angiotensin II (A(II)).

UNIFESP,ESCOLA PAULISTA MED,DIV NEPHROL,SAO PAULO,BRAZILUNIFESP,ESCOLA PAULISTA MED,DIV NEPHROL,SAO PAULO,BRAZILWeb of Scienc