Necrosis papilar renal bilateral de resolución espontánea como causa de hematuria microscópica. Caso clínico / Bilateral renal papillary necrosis of spontaneous resolution as a cause of microscopic hematuria. Report of one case

Renal papillary necrosis is an infrequent cause of hematuria characterized by ischemic necrosis of the renal medulla, especially the papilla. Its most common cause is analgesic abuse. Despite being oligo-symptomatic, in many cases its presence is associated with serious functional sequelae. Imaging, especially computed tomography, is essential to make the diagnosis. We report a 63-year-old female studied for an asymptomatic microscopic hematuria whose tomographic study showed a bilateral renal papillary necrosis. No etiology was found, and she evolved with a spontaneous complete remission.

Renal expression of AQP1 in the high-fat nutritional obesity of rat / Expresión renal de AQP1 en la obesidad nutricional alta en grasas en ratas

AQP1 plays an essential role in maintaining body water balance. In the kidney, AQP1 is localized to the apical and basolateral membrane of epithelial cells in the proximal tubule and descending thin limb of Ansa nephroni (Henle's loop) where it reabsorbs the vast majority of filtered water. The growing epidemic of obesity and metabolic diseases particularly obesity-related kidney disease is getting more and more attention in this century. However, a full understanding of mechanisms involved to the progressive renal disease is still unclear, in particular AQPs in the kidney of obesity. In this paper, we examined the localization of AQP1 in renal cortex and medulla of ND (normal diet) and HFD (high-fat diet) at rats. In the renal cortex and medulla, immunolight microscopy revealed weak expression of AQP1 in the apical and basolateral membrane of epithelial cells at the proximal straight/convoluted tubule of HFD compared with ND, respectively. The same result was confirmed in the thick descending limb and descending thin limb of Henle's loop. In the high-fat nutritional obesity of rats, decreased AQP1 levels may not directly cause serious obesity-related kidney disease, e.g. chronic kidney disease, even end-stage renal disease. But at least, AQPs (AQP1 in this study) was one of initially conditions to the incentive of obesity-related kidney disease.

Las acuoporinas tipo 1 (AQP1) constituyen una parte esencial en el mantenimiento del equilibrio del agua en el cuerpo. En el riñón, la AQP1 se localiza en la membrana apical y basolateral de las células epiteliales, en el túbulo proximal y en el segmento descendente del Ansa nephroni o asa nefrónica (asa de Henle), donde reabsorbe la gran mayoría de agua filtrada. La creciente epidemia de obesidad y enfermedades metabólicas en el siglo actual, hacen que la enfermedad renal relacionada con la obesidad esté recibiendo cada vez más atención. Sin embargo, aún no existe un conocimiento definitivo de los mecanismos implicados en la enfermedad renal progresiva, en particular los relacionados a las acuoporinas renales en la obesidad. En este trabajo, examinamos la localización de AQP1 en la corteza y la médula renales de la dieta normal (DN) y dieta alta en grasa (DAG) en ratas. En la corteza y médula renales, la microscopía de luz reveló una expresión débil de AQP1 en la membrana apical y basolateral de las células epiteliales en el túbulo contorneado proximal del grupo DAG en comparación con el grupo DN, respectivamente. El mismo resultado se confirmó en la porción descendente gruesa y en la porción descendente delgada del asa nefrónica. En ratas del grupo DAG, la disminución de los niveles de AQP1 pudo no ser la causa directa de una enfermedad renal grave relacionada con obesidad, como por ejemplo, enfermedad renal crónica, o una enfermedad renal terminal. No obstante, en este estudio, la expresión renal de AQP1 constituyó una de las condiciones iniciales para inducir la enfermedad renal relacionada con obesidad.

Expression of V2R and AQPs in the renal medulla of high-fat nutritional obesity of rat / Expresión de V2R y AQPs en la médula renal de ratas con obesidad nutricional alta en grasas

Recent evidence has indicated that adipose tissue produces bioactive substances that contribute to obesity-related kidney disease, altering the renal function and structure. Eight of the AQPs are expressed in the kidney, where several of them contribute to water absorption and maintenance of body water balance. In the study, we mainly examined the localization of AQP2, AQP3 and V2R in renal medulla of Normal Diet (ND) and High-fat Diet (HFD) of rats, respectively. In renal medulla of HFD, immunolight microscopy revealed weak expression of AQP2 at the apical plasma membrane and intracellular vesicles of principal cells of the IMCD and OMCD. AQP3 and V2R expression also observed a decrease in immunolabelling in the IMCD and OMCD. It was suggested that excess lipid accumulation may lead to lipotoxicity and may be the major driver of organ dysfunction such as water reabsorption dysfunction, which may be resulted from abnormal response of rphan G-protein-coupled receptors in kidney.

La evidencia reciente ha indicado que el tejido adiposo produce sustancias bioactivas que contribuyen a la enfermedad renal relacionada con la obesidad, alterando la función y la estructura renal. Ocho de los AQP se expresan en el riñón, donde varios de ellos contribuyen a la absorción de agua y al mantenimiento del equilibrio hídrico corporal. En el estudio, examinamos principalmente la localización de AQP2, AQP3 y V2R en la médula renal de ratas con dieta normal (ND) y ratas con dieta alta en grasas (HFD). En la médula renal del grupo HFD, la microscopía electrónica de barrido reveló una expresión débil de AQP2 en la membrana plasmática apical y las vesículas intracelulares de las células principales de IMCD y OMCD. La expresión de AQP3 y V2R también observó una disminución en el inmunomarcador en IMCD y OMCD. Se sugiere que el exceso de acumulación de lípidos puede conducir a lipotoxicidad y ser el principal impulsor de la disfunción orgánica, como la disfunción de reabsorción de agua, que puede ser el resultado de la respuesta anormal de los receptores acoplados a proteína rphan G en el riñón.

Expression of aquaporin 2, aquaporin 3 and aquaporin 4 in renal medulla of Bactrian camel ( Camelus bactrianus ) / Expresión de acuaporina 2, acuaporina 3 y acuaporina 4 en la médula renal del camello bactriano ( Camelus bactrianus )

SUMMARY: Aquaporins (AQPs) are members of the aquaporin water channel family that play an important role in reabsorption of water from the renal tubular fluid to concentrate urine. Using immunohistochemical staining on paraffin sections, We studied expression of AQP2, AQP3 and AQP4 in renal medulla of Bactrian camel (Camelus bactrianus). The renal medulla of cattle (Bos taurus) acted as the control. Compared with the control, strong expression of AQP2 was observed at the apical plasma membrane and intracellular vesicles, in both the outer medullary collecting duct (OMCD) and the inner medullary collecting duct (IMCD) of camel. Strong expression of AQP3 was observed at the basolateral plasma membrane of the IMCD of camel. Strong AQP4 expression, however, was observed at the basolateral plasma membrane in the OMCD of camel. Moreover, moderate AQP4 expression was detected in endothelium of capillary in medullary region of camels, whereas very weak/absent expression was detected in endothelium of capillary of cattle. We concluded that expression of AQP2, AQP3 and AQP4 in the camel kidney showed some differences from cattle in renal trans-epithelial water transport. It may enhance our better understanding of special water metabolism mechanisms that enable camels to survive in extreme environments.

RESUMEN: Las acuaporinas (AQP) son miembros de las proteínas de transporte que desempeñan un papel importante en la reabsorción de agua del líquido tubular renal para concentrar la orina. Estudiamos la expresión de AQP2, AQP3 y AQP4 en la médula renal del camello bactriano (Camelus bactrianus) usando tinción inmunohistoquímica en secciones de parafina. La médula renal del bovino (Bos taurus) se usó como control. En comparación con el control, se observó una fuerte expresión de AQP2 en la membrana plasmática apical y vesículas intracelulares tanto en el conducto colector medular externo (CCME) como en el conducto colector medular interno (CCMI) del camello. Se observó una fuerte expresión de AQP3 en la membrana plasmática basolateral del CCMI del camello. También se observó una expresión fuerte de AQP4 en la membrana plasmática basolateral en el CCME de camello. Además, se detectó una expresión moderada de AQP4 en el endotelio de los capilares en la región medular de los camellos, mientras que en el endotelio de los capilares del bovino se detectó una expresión muy débil. Concluimos que la expresión de AQP2, AQP3 y AQP4 en el riñón de camello mostró algunas diferencias con el bovino en el transporte trans-epitelial de agua renal. El estudio podría mejorar nuestra comprensión de los mecanismos especiales del metabolismo del agua que permiten a los camellos sobrevivir en ambientes extremos.

Effect of aqueous extract of [eryngium campestre] on the prevention of pathologic alterations caused by calcium oxalate crystals induced by ethylene glycol in the cortex and medulla of rats' kidneys

Background and Aim: Due to the effects of herbs in the prevention of kidney stones, the present study aimed at assessing the effect of aqueous eryngium campestre on the prevention of pathologic alterations caused by calcium oxalate crystals induced by ethylene glycol in the cortex and medulla of rats'kidneys

Materials and Methods: To conduct the study 40 male Wistar rats, weighing 200 - 250 gr were randomly divided into 5 equal groups; i.e. the healthy control group that just received water, the negative control group receiving water with 1% ethylene glycol, the prevention groups, which in addition to 1% ethylene glycol in water were daily gavaged with 100 mg/kg, 200mg/kg, and 400 mg/kg of the plant extract. After 30 days all rats were killed and slides from each one's kidneys were prepared. The slides were stained applying H/E method and the number of their calcium oxalate crystals was checked

Results: It was found that there was a significant difference between the number of their calcium oxalate crystals in the control health and negative groups [P<0.05]. But, in the prevention group gavaged 100 mg/kg there was no significant difference with the negative group, [P>0.05]. However, in the 200mg/kg prevention group compared to the negative control one there was a significant difference in reducing the number of the crystals [P<0.05]. But in 400mg/kg the prevention group there was no significant difference with the negative control group [P>0.05]

Conclusion: It was discovered that aqueous extract of eryngium campestre is effective in preventing the accumulation of calcium oxalate crystals in the kidney

Possible senescence associated change in the predominant &alpha -Na+/K+ ATP-ase isoform in the renal cortex of the rat

With aging the kidney exhibits progressive deterioration, with a decrease in renal function. Most of the filtered Na+ is actively reabsorbed in the proximal tubules through different transporters located in apical membrane. This process is possible because basolateral Na+/K+-ATP-ase generates electrochemical conditions necessary for energetically favorable Na+ transport. The α-subunit is the catalytic domain of Na+/K+-ATP-ase. There are three isoforms of the α/subunit present in rat kidney. The present study was undertaken to examine the expression pattern of rat α-Na+/K+-ATP-ase during senescence. We tested the impact of aging on mRNA expression of α-Na+/K+-ATP-ase in cortex and medulla of aged Wistar rats. We observed a significant expression decrease in mRNA levels and a possible change of isoform in the cortex of aged animals. These expression changes observed for αsubunit could be contributing to affect the renal function in conditions of water and salt stress.

Con el avance de la edad los riñones exhiben un deterioro funcional progresivo con disminución de la función renal. La mayor parte del sodio (Na+) filtrado es reabsorbido activamente en los túbulos proximales a través de diferentes transportadores ubicados en la membrana apical. Este proceso es posible por la existencia de la Na+/K+-ATP-asa basolateral, que genera las condiciones electroquímicas necesarias para que el transporte de Na+ sea energéticamente favorable. La subunidad αde la Na+/K+-ATP-asa es el dominio catalítico de la enzima. Existen tres isoformas de subunidad α, que están presentes en el riñón de la rata. En este trabajo se examinan los patrones de expresión de la α-Na+/K+-ATP-asa durante la senescencia. Se estudió así si el aumento de la edad incidía en la expresión del ARNm de la α-Na+/K+-ATP-asa en corteza y médula renal de ratas Wistar senescentes. Se observó una disminución en la expresión del ARNm de la subunidad αy un posible cambio de isoforma predominante en la corteza de los animales senescentes. Los cambios observados para la expresión de la subunidad αpodrían contribuir a afectar la función renal en condiciones de estrés hídrico y salino.

Avaliação da morfometria renal através do método ultrassonográfico de fêmeas caprinas (Capra hircus) normais da raça Saanen / Renal morphometric evaluation by ultrasonographic techniques in normal female Saanen goats (Capra hircus)

A utilização de técnicas ultrassonográficas na área de Medicina Veterinária está cada vez mais presente e a capacitação nesta área tornou-se indispensável para o clínico, auxiliando-o na obtenção de informações rápidas e valiosas das afecções patológicas que podem acometer os animais. O exame ultrassonográfico renal revelou-se de grande importância neste âmbito, com o objetivo de avaliar e mensurar os parâmetros morfométricos renais normais de fêmeas caprinas (Capra hircus). Por meio de técnicas ultrassonográficas procedeu-se o estudo de 30 fêmeas da raça Saanen, divididas em três grupos: fêmeas com idade inferior a 6 meses (3,0±1,0 meses), de 6-18 meses (9,0±4,3 meses) e com idade superior a 18 meses (46,3±17,4 meses). Realizaram-se imagens dos rins, em secções longitudinais, medidas de comprimento e largura e, em secções transversais, medidas de altura (ou espessura). Com estes valores calcularam-se volumes renais, corticais e medulares, além da relação cortico-medular. Com relação ao comprimento renal os grupos com idade inferior a 6 meses, de 6-18 meses e com idade superior a 18 meses obtiveram média e desvio padrão de 4,20±0,36cm, 5,56±0,40cm e 6,77±0,64cm, respectivamente. Tratando-se do volume renal, estes grupos apresentaram média e desvio padrão de 17,02±3,99cm³, 19,99±5,86cm³; e, 41,23±13,05cm³. Comparou-se a equivalência métrica das médias entre os dois rins de forma que os parâmetros volumétricos e lineares renais com diferença entre si são comprimento renal, volume renal e volume cortical para o grupo de fêmeas com idade de 6-18 meses, e comprimento renal e comprimento medular para o grupo com idade superior a 18 meses. Entre diferentes grupos observou-se que somente o comprimento medular esquerdo apresentou média equivalente em todos os grupos, ou seja, entre o grupo com idade inferior a 6 meses e o grupo com idade de 6-18 meses e, entre este último e o grupo com idade superior a 18 meses. Os resultados mostraram correlações diretas e positivas entre peso corporal e idade com os parâmetros lineares e volumétricos, a relação cortico-medular esquerda foi a única que apresentou correlação significativa com o peso (r= -0,365; P = 0,047). Para aqueles parâmetros que apresentaram correlação significativa foi realizada análise de regressão, obtendo-se a linha de melhor ajuste das variáveis.

The veterinary ultrasonographic techniques have increased in the veterinary doctor's daily work, therefore training and knowing how to use ultrasound equipment have become needful to the animals healthcare professionals. It's important remember that ultrasound equipment makes possible getting valuable pathological data from animals' health. In this background, the renal ultrasonographic test has gotten an important place and, nowadays, it is possible measure with accuracy the caprine renal morphometrics parameters (Capra hircus). Through ultrasonographic techniques, it has done a stocktaking with three groups of normal goats: older than 18 months (46.3±17.4 months), younger than 6 months (3.0±1.0 months) and age between 6 and 18 months (9.0 4.3 months), totalizing 30 samples of the female Saanen kind. In longitudinal section of the kidneys, measured the length and breadth and, in transverse section, measured the height (or thickness). The values obtained calculated the renal, cortical and medullary volumes, besides corticomedullary correlation. The renal length of the groups younger than 6 months, age between 6 and 18 months and older than 18 months had mean and standard deviation of 4.20±0.36cm; 5.56±0,40cm; and, 6.77±0.64cm, respectively. To the renal volume theses groups had mean and standard deviation of 17.02±3.99cm³; 19.99±5.86cm³; and, 41.23±13.05cm³. It was compared the metrical equivalence of the mean between the two kidneys, to the group with age between 6 and 18 months the parameters showed difference were renal length, renal volume and cortical volume, in other hand to the group older than 18 months it was renal length and medullar length. Comparing different groups was noted that only the left medullar length had equivalent mean in all the groups, it means, the group younger than 6 months, older than 18 months and from 6 to 18 months of age. The results showed direct and positive correlation between corporal weight and age with the linear and volumetric parameters The left corticomedullary correlation was the only of its kind to exhibit significant correlation with the weight (r= -0.365; P value 0.047). The parameters with significant correlation had the regression analysis done, obtained the better line of adjust of the variables.

Tubulocystic carcinoma of kidney associated with papillary renal cell carcinoma.

Tubulocystic renal cell carcinoma (TCRCC) is a rare variant of renal cell carcinoma, which has distinct histology but there is some controversy about its association with papillary renal cell carcinoma (PRCC) and cell of origin in literature. We report an 18-year-old girl with the rare TCRCC of kidney associated with PRCC with metastases to the para-aortic nodes. The patient presented with hematuria and a right renal mass with enlarged regional nodes for which a radical nephrectomy with retroperitoneal lymph node dissection was done. On gross examination, a solid cystic lesion involving the lower pole and middle pole of the kidney measuring 12x9x9 cm was seen along with an additional cystic lesion in upper pole of kidney. Microscopically the main tumor showed the typical histology of a tubulocystic carcinoma with multiple cysts filled with secretions lined by variably flattened epithelium with hobnailing of cells. The mass in the upper pole was a high-grade PRCC and the nodal metastases had morphology similar to this component. To conclude, at least a small but definite subset of TCRCC is associated with PRCC, and cases associated with PRCC do seem to have a higher propensity for nodal metastasis as in the case we report.

Role of nitric oxide and prostaglandin in the maintenance of cortical and renal medullary blood flow

This study was undertaken in anesthetized dogs to evaluate the relative participation of prostaglandins (PGs) and nitric oxide (NO) in the maintenance of total renal blood flow (TRBF), and renal medullary blood flow (RMBF). It was hypothesized that the inhibition of NO should impair cortical and medullary circulation because of the synthesis of this compound in the endothelial cells of these two territories. In contrast, under normal conditions of perfusion pressure PG synthesis is confined to the renal medulla. Hence PG inhibition should predominantly impair the medullary circulation. The initial administration of 25 µM kg-1 min-1 NG-nitro-L-arginine methyl ester produced a significant 26 percent decrease in TRBF and a concomitant 34 percent fall in RMBF, while the subsequent inhibition of PGs with 5 mg/kg meclofenamate further reduced TRBF by 33 percent and RMBF by 89 percent. In contrast, the initial administration of meclofenamate failed to change TRBF, while decreasing RMBF by 49 percent. The subsequent blockade of NO decreased TRBF by 35 percent without further altering RMBF. These results indicate that initial PG synthesis inhibition predominantly alters the medullary circulation, whereas NO inhibition decreases both cortical and medullary flow. This latter change induced by NO renders cortical and RMBF susceptible to a further decrease by PG inhibition. However, the decrease in medullary circulation produced by NO inhibition is not further enhanced by subsequent PG inhibition.

The investigation of macrophage infiltration in the early phase of ischemic acute renal failure in mice

BACKGROUND/AIMS: Inflammation plays a key role in ischemic acute renal failure (ARF). The present study investigated the infiltration of macrophages in the early phase of ischemic ARF in mice. METHODS: Ischemic ARF was induced by renal clamping for 22 min, while the control mice underwent sham surgery (no clamping). The serum creatinine and blood urea nitrogen (BUN) levels were measured in the control and post-ischemia mice. Immunofluorescence staining was used to measure the number of CD 11b-positive cells in the kidney tissue sections to determine the amount of post-ischemic macrophage infiltration. Lipo-Cl2MBP (clodronate) for macrophages depletion was injected via a tail vein 5 d before ischemia induction and again 2 d before ischemia induction. RESULTS: The study found that the post-ischemia mice had higher levels of serum creatinine and BUN at 16 and 24 h compared to the controls. Immunofluorescence staining showed there were more macrophages in the post-ischemic tissue at 2, 8, 16 and 24 h compared to the control tissue, and that most of these macrophages were located in the outer medulla. The mice treated with clodronate prior to ischemia induction were found to have lower levels of serum creatinine compared to those mice that weren't treated with clodronate. CONCLUSIONS: There was significant infiltration of macrophages from the early phase of ischemic ARF, and this peaked at 16-24 h. Macrophage depletion using clodronate was protective against ischemic ARF.

Solubilization of Na, K-ATPase from rabbit kidney outer medulla using only C12E8

SDS, C12E8, CHAPS or CHAPSO or a combination of two of these detergents is generally used for the solubilization of Na,K-ATPase and other ATPases. Our method using only C12E8 has the advantage of considerable reduction of the time for enzyme purification, with rapid solubilization and purification in a single chromatographic step. Na,K-ATPase-rich membrane fragments of rabbit kidney outer medulla were obtained without adding SDS. Optimum conditions for solubilization were obtained at 4ºC after rapid mixing of 1 mg of membrane Na,K-ATPase with 1 mg of C12E8/ml, yielding 98 percent recovery of the activity. The solubilized enzyme was purified by gel filtration on a Sepharose 6B column at 4ºC. Non-denaturing PAGE revealed a single protein band with phosphomonohydrolase activity. The molecular mass of the purified enzyme estimated by gel filtration chromatography was 320 kDa. The optimum apparent pH obtained for the purified enzyme was 7.5 for both PNPP and ATP. The dependence of ATPase activity on ATP concentration showed high (K0.5 = 4.0 æM) and low (K0.5 = 1.4 mM) affinity sites for ATP, with negative cooperativity. Ouabain (5 mM), oligomycin (1 æg/ml) and sodium vanadate (3 æM) inhibited the ATPase activity of C12E8-solubilized and purified Na,K-ATPase by 99, 81 and 98.5 percent, respectively. We have shown that Na,K-ATPase solubilized only with C12E8 can be purified and retains its activity. The activity is consistent with the form of (alphaß)2 association

Hipertensión arterial dependiente de sal / Salt-sensitive arterial hypertension

En cerca del 50 por ciento de los pacientes hipertensos esenciales la hipertensión es sensible a sal, esta característica se acentúa y su frecuencia aumenta con la edad y se asocia con un mayor riesgo de complicaciones cardiovasculares y de nefropatía. El mecanismo responsable no se ha establecido en precisión, aunque se ha sugerido de participación de distintos factores vasoactivos. La sensibilidad a sal implica una alteración en la relación presión arterial excreción de sodio o "natriuresis de presión" la cual se desplaza a la derecha, es decir que se requiere una presión arterial más alta para mantener la excreción normal de sal. Estudios experimentales sugieren que esta alteración es producida por aumento en la resistencia de vasos preglomerulares secundaria a hipertrofia de la pared vascular, y disminución de la permeabilidad glomerular, además ocurren alteraciones tubulointersticiales que dan lugar a generación local de factores vasoactivos, citocinas y factores de crecimiento, que acentúan los cambios hemodinámicos y disminuyen la excreción renal de sodio.

Correlaçäo entre quimerismo hematopoético e doença residual mínima em pacientes portadores de leucemia mielóide crônica submetidos a transplante alogênico de medula óssea, através da análise comparativa do VNTR, FISH e RT-PCR multiplex / Correlation between hematopoietic chimerism and minimal residual disease in patients with chronic myelogenous leukemia submitted to allogenic bone marrow transplantation by cooperative analysis of VNTR, FISH and RT-PCR multiplex

OBJETIVO: Identificaçao de quimerismo hematopoético após transplante de, medula óssea alogênico em pacientes portadores de leucemia mielóide, crônica, e compará-lo à avaliaçao de doença residual mínima detectada pela análise molecular do rearranjo gênico bcr-abl MÉTODO: Foram avaliados 29 pacientes em duas fases distintas do TMO e, seus respectivos doadores em relaçao ao quimerismo hematopoético através da análise do VNTR pela técnica de PCR através dos primers APO-, B e D1 S80. A observaçao da fusao gênica bcr-abl foi realizada na fase final deste estudo por dois métodos. O primeiro, RT-PCR Multiplex, utilizou os, primers BCR (b2), BCR (rev) e ABL (a3). O segundo, FISH, que utilizou a sonda de thibridizaçao bcr-abl, detectou o rearranjo bcr-abl através da, observaçao em microscópio de fluorescência. O padrao ouro foi definido como a recaída hematológica. RESULTADOS: A comparaçao dos VNTR dos doadores e pacientes nas duas fases pré-estabelecidas mostrou que houve tendência à significância na comparaçao do quimerismo misto do D1 S80 com o padrao ouro e significância com a recaída molecular avaliada pelo FISH e RT-PCR Multiplex. A análise do primer APO-B nao mostrou significância quando comparada ao D1 S80, FISH, RT-PCR Multiplex ou padrao ouro. Quando o FISH e o RT-PCR Multiplex foram comparados com o padrao ouro, a concordância foi de 78,2 por cento e 44,2 por cento, respectivamente. A concordância entre ambos foi de 61 por cento...(au)

Standardization of a fluorimetric assay for the determination of tissue angiotensin-converting enzyme activity in rats

The tripeptide Hip-His-Leu was used to standardize a fluorimetric method to measure tissue angiotensin-converting enzyme (ACE) activity in rats. The fluorescence of the o-phthaldialdehyde-His-Leu adduct was compared in the presence and absence of the homogenate (25 µl) to determine whether the homogenate from different tissues interfered with the fluorimetric determination of the His-Leu product. Only homogenates from lung and renal medulla and cortex showed significantly altered fluorescence intensity. To overcome this problem, the homogenate from these tissues were diluted 10 times with assay buffer. The specificity of the assay was demonstrated by the inhibition of ACE activity with 3 µM enalaprilat (MK-422). There was a linear relationship between product formation and incubation time for up to 90 min for homogenates of renal cortex and medulla and liver, for up to 60 min for ventricles and adrenals and for up to 30 min for the aorta, lung and atrium homogenates. In addition, there was a linear relationship between product formation and the amount of protein in the homogenates within the following range: lung, 30-600 µg; renal cortex and medulla, 40-400 µg; atrium and ventricles, 20-200 µg; adrenal, 20-100 µg; aorta, 5-100 µg; liver, 5-25 µg. No peptidase activity against the His-Leu product (31 nmol), assayed in borate buffer (BB), was detected in the different homogenates except the liver homogenate, which was inhibited by 0.1 mM r-chloromercuribenzoic acid. ACE activity in BB was higher than in phosphate buffer (PB) due, at least in part, to a greater hydrolysis of the His-Leu product in PB. ACE activity of lung increased 20 percent when BB plus Triton was used. Enzyme activity was stable when the homogenates were stored at -20o or -70oC for at least 30 days. These results indicate a condition whereby ACE activity can be easily and efficiently assayed in rat tissue samples homogenized in BB using a fluorimetric method with Hip-His-Leu as a substrate.

Hiperecogenicidad transitoria de las papilas renales en recién nacidos sanos / Echogenic renal pyramids in neonates

El objetivo del presente trabajo fue estudiar la morfoestructura renal en neonatos sanos de 1 a 15 días de vida, evaluando si la hiperecogenicidad transitoria de las papilas renales (HTPR) observada es una variante de la normalidad, con revisión y puesta al día de la literatura sobre el tema. De los 574 examinados el 7,1 por ciento (41 pacientes) presentó HTPR en ambos riñones. Se controlaron dentro del primer mes de vida a 39 pacientes constatándose en todos los casos desaparición del fenómeno. Consideramos éste hallazgo ecográfico como una variante normal diferente de otras patologías que manifiestan con imágenes semejantes. Si existieran dudas desde el punto de vista clínico sugerimos realizar el seguimiento ecográfico a partir de los 15 días de vida siendo la evolución natural de la HTPR su completa desaparición

Changes in antioxidant enzyme activities and lipid peroxidation related to bromoethylamine-induced renal cytotoxicity

Background. The effect of bromoethylamine (BEA) administration on lipid peroxidation and on the activieties of antioxidant enzymes was studied. Methods. Adult rats received BEA at 1.2 mmol/kg, a dose that produces renal papillary necrosis. Lipid peroxidation assessed by maximal rate in MDA formation, the activities of catalase, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the levels of non-protein sulfhydryls (NPSH) were measured in renal cortex and papilla of control and BEA-treated animals. Results. After BEA treatment, an increment in lipid peroxidation in papilla and cortex was found after 1.5 and 24 hours of treatment. Catalase activity decreased in both regions, but earlier cortex. Conclusion. These data suggest some role of oxidative stress in the mechanism of BEAinduced papillary necrosis

La presión del intersticio renal en el control crónico de la presión arterial / The role of renal interstitial pressure on the chronic control of arterial blood pressure

Existe extensa evidencia de que el riñón participa en forma importante en la generación y mantenimiento de la hipertensión arterial. Esta evidencia proviene de modelos animales experimentales, de cepas de ratas con hipertensión genética y de estudios en humanos. Todos los genes identificados hasta la fecha en los que mutaciones puntuales producen alteraciones crónicas en la presión arterial, codifican para proteínas que participan en una vía común que tiene, con fin la reabsorción renal de sodio. La natriuresis de presión constituye el mecanismo de enlace entre la presión arterial y la excreción urinaria de sodio; en los últimos años hemos empleado a entender cómo se da la conexión entre presión arterial y natriuresis ya que se ha reconocido, la importancia de la presión del intersticio renal en este fenómeno. Parte del nuevo entendimiento de la fisiología de la excreción urinaria de sodio se debe al desarrollo de nuevas estrategias como la videomicroscopía y flujometría doppler-laser que permiten medir, con alto grado de certeza, los flujos sanguíneos de corteza y médula renales en forma independiente que, en combinación con estrategias ya conocidas como la implantación de cápsulas para determinación de la presión intersticial renal, muestran que la presión del intersticio renal es la responsable de la conexión entre la presión arterial sistémica y la natriuresis y por tanto, modula la presión arterial a largo plazo

Na, K-ATPase: a molecular target for Leptospira interrogans endotoxin

On the basis of our report that a glycolipoprotein fraction (GLP) extracted from Leptospira interrogans contains a potent inhibitor of renal Na,K-ATPase, we proposed that GLP-induced inhibition of Na,K-ATPase might be the primary cellular defect in the physiopathology of leptospirosis. The present study was designed to test this hypothesis by determining whether or not 1) GLP inhibits all the isoforms of Na,K-ATPase which are expressed in the tissues affected by leptospirosis, 2) Na,K-ATPase from leptospirosis-resistant species, such as the rat, is sensitive to GLP, 3) GLP inhibits Na,K-ATPase from intact cells, and 4) GLP inhibits ouabain-sensitive H,K-ATPase. The results indicate that in the rabbit, a leptospirosis-sensitive species, GLP inhibits with similar efficiency (apparent IC5O: 120-220 mug protein GLP/ml) all isoforms of Na,K-ATPase known to be expressed in target tissues for the disease. Na,K-ATPase from rat kidney displays a sensitivity to GLP similar to that of the rabbit kidney enzyme (apparent IC50: 25-80 and 50-150 mug protein GLP/ml for rat and rabbit, respectively), indicating that resistance to the disease does not result from the resistance of Na,K-ATPase to GLP. GLP also reduces ouabain-sensitive rubidium uptake in rat thick ascending limbs (pmol mm-1 min-1 ñ SEM; control: 23.8 ñ 1.8; GLP, 88 mug protein/ml: 8.2 ñ 0.9), demonstrating that it is active in intact cells. Finally, GLP had no demonstrable effect on renal H,K-ATPase activity, even on the ouabain-sensitive form, indicating that the active principle of GLP is more specific for Na,K-ATPase than ouabain itself. Although the hypothesis remains to be demonstrated in vivo, the present findings are compatible with the putative role of GLP-induced inhibition of Na,K-ATPase as an initial mechanism in the physiopathology of leptospirosis.

Factors affecting the ability of the renal medulla to exert an antihypertensive function.

To examine whether changes in renomedullary osmolality and the activity of the renin-angiotensin system may influence the ability of the renal medulla to exert an antihypertensive function, rats were exposed to several manoeuvers. These affected either the medullary osmolality or the renin-angiotensin system (salt or saccharose load, salt depletion, treatment with captopril alone or in combination with salt depletion). A comparison of the antihypertensive capacity of the renal medulla was studied by transplanting renal medullae from the various groups into one-kidney one-clip hypertensive rats. A significant and quantitatively similar reduction in blood pressure was observed in hypertensive rats that received transplants of the medullae from control, salt or saccharose loaded rats and captopril treated rats. In contrast, medullae from salt depleted rats did not affect blood pressure when transplanted into hypertensive animals. The addition of captopril restored the antihypertensive function of renal medulla in salt depleted rats. The results do not support the view that osmolality of the renal medulla regulates its antihypertensive capacity, and suggest that angiotensin II may restrain renomedullary antihypertensive function.