Localization of Diacylglycerol Kinase ζ in the Kidney of Adult Rats: Its Dominant Expression in Collecting Tubules and its Selective Lack in Proximal Tubules / Localización de Diacilglicerol Quinasa ζ en el Riñón de Ratas Adultas: su Expresión Dominante en Túbulos Colectores y su Carencia Selectiva en Túbulos Proximales

SUMMARY: Diacylglycerol kinase (DGK) exerts balancing the intracellular level between two-second messengers, diacylglycerol and phosphatidic acid, by its phosphorylation activity. DGK ζ is often localized in cell nuclei, suggesting its involvement in the regulation of intranuclear activities, including mitosis and apoptosis. The present immunohistochemical study of rat kidneys first revealed no detection levels of DGK ζ -immunoreactivity in nuclei of most proximal tubule epithelia in contrast to its distinct occurrence in cell nuclei of collecting and distal tubules with the former more dominant. This finding suggests that DGK ζ is a key factor regulating vulnerability to acute kidney injury in various renal tubules: its low expression represents the high vulnerability of proximal tubule cells, and its distinct expression does the resistance of collecting and distal tubule cells. In addition, this isozyme was more or less localized in nuclei of cells forming glomeruli as well as in endothelial nuclei of peritubular capillaries and other intrarenal blood vessels, and epithelial nuclei of glomerular capsules (Bowman's capsules) and renal calyces, including intrarenal interstitial cells.

La diacilglicerol quinasa (DGK) ejerce el equilibrio del nivel intracelular entre dos segundos mensajeros, diacilglicerol y ácido fosfatídico, por su actividad de fosforilación. La DGK ζ a menudo se localiza en los núcleos celulares, lo que sugiere su participación en la regulación de las actividades intranucleares, incluidas la mitosis y la apoptosis. El presente estudio inmunohistoquímico en riñones de rata no reveló niveles de detección de inmunorreactividad de DGK ζ en los núcleos de la mayoría de los epitelios de los túbulos proximales, en contraste a la detección en los núcleos celulares de los túbulos colectores y distales, siendo el primero más dominante. Este hallazgo sugiere que DGK ζ es un factor clave que regula la vulnerabilidad a la lesión renal aguda en varios túbulos renales: su baja expresión representa la alta vulnerabilidad de las células del túbulo proximal, y su expresión distinta hace a la resistencia de las células del túbulo colector y distal. Además, esta isoenzima estaba más o menos localizada en los núcleos de las células que forman los glomérulos, así como en los núcleos endoteliales de los capilares peritubulares y otros vasos sanguíneos intrarrenales, y en los núcleos epiteliales de las cápsulas glomerulares (cápsulas de Bowman) y los cálices renales, incluidas las células intersticiales intrarrenales.

Diagnóstico de infección por VIH por el hallazgo incidental de alteraciones ultraestructurales en una biopsia renal: Report of one case / Ultrastructural alterations in renal biopsy leading to the diagnosis of HIV infection

HIV infection has different clinical presentations. We report a 21-year-old male with longstanding isolated microscopic hematuria attributed to thin glomerular basement membrane disease, who after 15 years of follow-up presented with significant proteinuria. A kidney biopsy was performed, revealing the presence of tubulo-reticular inclusions in the glomerular endothelial cells. This finding led to suspect an HIV infection, which was verified. Antiretroviral therapy, angiotensin-converting enzyme and angiotensin II receptor blockers were prescribed. At 6 years of diagnosis the patient is asymptomatic and has normal kidney function. Microscopic hematuria and low level proteinuria persists.

Low-Intensity physical activity beneficially alters the ultrastructural renal morphology of spontaneously hypertensive rats

INTRODUCTION AND OBJECTIVE: Kidney disorders can cause essential hypertension, which can subsequently cause renal disease. High blood pressure is also common among those with chronic kidney disease; moreover, it is a well-known risk factor for a more rapid progression to kidney failure. Because hypertension and kidney function are closely linked, the present study aimed to observe the beneficial effects of low-intensity physical activity on structural and ultrastructural renal morphology and blood pressure in normotensive and spontaneously hypertensive rats. METHOD: Male Wistar-Kyoto rats and spontaneously hypertensive rats were randomly allocated into four groups: sedentary or exercised Wistar-Kyoto and sedentary or exercised spontaneously hypertensive rats. The exercise lasted 20 weeks and consisted of treadmill training for 1 hour/day, 5 days/week. RESULTS: The exercised, spontaneously hypertensive rats showed a significant blood pressure reduction of 26 percent. The body masses of the Wistar-Kyoto and spontaneously hypertensive strains were significantly different. There were improvements in some of the renal structures of the animals treated with physical activity: (i) the interdigitations of the proximal and distal convoluted tubules; (ii) the basal membrane of the proximal and distal convoluted tubules; and (iii) in the basal membrane, slit diaphragm and pedicels of the glomerular filtration barrier. The spontaneously hypertensive rats also showed a decreased expression of connexin-43. CONCLUSION: Physical exercise could be a therapeutic tool for improving kidney ultrastructure and, consequently, renal function in hypertensive individuals.

Ultrastructural changes of the renal tubular cells and hepatocytes of neonatal rats suckled milk from mothers subjected to subchronic toxicity of cadmium chloride

Neonatal off springs from female rats administered cadmium chloride by the oral route [0.5 mg.kg[-1]. day[-1] throughout their entire gestation and lactation periods. The pups were nursed their mothers until they weaned at the age of 28 days. At the end of the experiment, neonatal rats were anaesthetized by ether, then dissected and liver and kidney tissues were rapidly removed and processed for transmission electron microscopic examination. The uItrastructural observations of the proximal convoluted tubules were the absent of the apical microvilli, basal striation and endocytotic-lysosomal apparatus. Meanwhile hepatocytes showed few, sporadic mitochondria in concomitant with ill developed rough and smooth endoplasmic reticula. In addition to the apoptosis of hepatocytes. In conclusion, cadmium was transmitted via milk to the rat pups and potentially toxic to proximal convoluted tubular cells and to less extent to hepatocytes with multifactor mechanisms of cadmium toxicity

Idiopathic intranuclear inclusion bodies in the renal tubular epithelia of Japanese quail (Coturnix coturnix japonica)

We report idiopathic intranuclear inclusion bodies in the renal tubular epithelia of two cases of among the 960 Japanese quail (Coturnix coturnix japonica) in the course of the acute oral toxicity and dietary toxicity test. Basophilic inclusion bodies were seen only in the nuclei of renal tubular epithelia. We could not classify our case into any adenovirus infection by clinical signs and lesions. The inclusion bodies were only identified as adenovirus-like particles based upon the electronmicroscopical features.

Structure of the kidney of Bufo arenarum: intermediate segment, distal tubule and collecting tubule

The ultrastructure of the intermediate segment (IS), distal tubule and collecting tubule (CT) of the south american toad Bufo arenarum, was studied by light and transmission electron microscopy. The IS is composed of cubical ciliated cells which propel the urine along the renal tubule. The distal tubule is divided into two portions: the early distal tubule (EDT) and the late distal tubule (LDT). The EDT is characterized by only one type of cells with well developed basolateral interdigitations and numerous elongated mitochondria, which are oriented normal to the basal surface. The "macula densa--like" is a specialized zone of the EDT in contact with the vascular pole, where cells are more tightly packed than in the rest of the tubule. The LDT shows two types of cells called dark and light cells according to the appearance of their cytoplasm. Dark cells have microplicae and few but long microvilli at their luminal surface, and abundant mitochondria in their cytoplasm. Light cells show basal and lateral infoldings and few mitochondria. The CT, which is composed of dark and light cells, exhibits an enlarged lumen with an undulated surface and dilated spaces between neighbouring cells. This work is a contribution to the knowledge of the kidney of B. arenarum; frequently used as an experimental model for physiological and biochemical studies.

Efecto del carcinogeno dimetilnitrosamina sobre el rinon del vison / Efect of carcinogen dimethylnitrasamine on the kidney of mink

Visones de un criadero que recibian alimentos, sobre la base de restos de pescado, evidenciaron un significativo aumento en su mortalidad, presencia de canceres hepaticos y alteraciones renales revelables histologicamente. Esos efectos fueron atribuibles a presencia, en el alimento, de dimetilnitrosamina (NDMA), en concentraciones 1,8 ug/g. En este trabajo se estudia en detalle el efecto de la NDMA sobre el rinon del vison. Visones que fueron tratados ip con NDMA(7 mg/kg en sol. fis.), mostraron dano evidenciable ultraestructuralmente en la corteza renal. El dano fue mayor en los tubulos proximales, que en los distales, pero era de naturaleza similar. Las celulas epiteliales tubulares de los animales intoxicados mostraron: a)Condensacion de la cromatina nuclear y dilatacion de la membrana perinuclear. b)Marcada hinchazon mitocondrial y ruptura de sus crestas con perdida de contenida de la matriz mitocondrial. c)Despegue de ribosomas y dilatacion del reticulo endoplasmico. d)Aumento del numero y tamano de las vacuolas autofagicas. e)Aparicion de gotas lipidicas en el citiplasma. En contraste con lo previamente establecido, para el caso de cancer hepatico del vison, el mecanismo del dano renal por NDMA no se pudo correlacionar directamente con la union de metabolitos reactivos de esta a proteinas o acidos nucleicos o la biotransformacion microsomal o mitocondrial de la NDMA o formaldehido. No obstante, el rinon biotransforma la NDMA a CO2, pero lo hace 3-4 veces menos intensamente que el rinon de rata. Los resultados sugeririan la presencia, en el caso del dano renal por NDMA, de mecanismos distintos de accion, a los habitualmente aceptados como responsables del dano hepatico o el renal en otras especies. Alternativamente, el dano renal puede deberse a dano hepatico concomitante

Sequência evolutiva dos lisossomos anormais encontrados nos túbulos renais do camundongo beige (Síndrome de Chediak-Higashi) / Evolutive sequence of abnormal lysosomes found in the kidney tubules of the beige mouse (Chediak-Higashi syndrome)

Estudamos as modificaçöes que podem ocorrer no rim do camundongo beige, em seqüência evolutiva acompanhada desde o nascimento até a idade adulta, usando a reaçäo para localizar a ß-glucoronidase e a reaçäo do ácido periódico-reativo de Schiff (PAS). Os resultados mostraram que ao nascimento ocorre um acúmulo de Schiff (PAS). Os resultados mostraram que ao nascimento ocorre um acúmulo de grânulos PAS positivos no primeiro segmento dos túbulos proximais representando glico proteínas que atravessaram os vaso glomerulares. Com o aumento da atividade enzimática as glico proteínas säo absorvidas pelas células da regiäo S3, acumulando-se sob a forma de grânulos PAS positivos nos camundongos beige. Isso seria motivado pelo fato de que apesar do aumento da atividade enzimática, os lisossomos seriam deficientes e näo conseguiriam degradar as proteínas

Specific cytochemical localization of sodium-potassium dependent adenosine-triphosphatase (Na -K -atp-ASE) activity in cortical renal tubules of rat kidney

Utilizid para-nitrophenil-phosphate as an unspecific substrate cytochemical methods have described for and electron microscopi localizarion of Na -K -ATP-ase activity (ATP-ase-A). However, when applied to renal tubules, these methods did not clearly reveal the quantitative and quantitative distribution of the enzime. In an attempt to improve this method, we evaluated shorter fixation times, using freh paraformaldehyde after immersion of the renal tissue in an isosmotic sucrose tris buffer solution and utilized ATP as the specific substrate for the ATP-ase. The results indicated good preservation of the tissue, and under these conditions ATP was able to penetrate of the cells allowing a reliable identification at the ultrastructural level, of the ATP-ase-A, associated with subcellular structures for with the enzymatic reaction was positive. The activity observed suggest that the basolateral plasma membranes of proximal and distal renal tubules are the major sites of sites of Na -K -ATP-ase localization. However, there was also significant hydrolitic activity detectived on the surface (brush border) of proximal convoluted tubules, that disappeared with the elimination of the Na and K from the incubation medium. In both cases enzymatic activities were insensitive to 10 mM Ouabain in the medium