Role of the alpha(1)- and alpha(2)-adrenoceptors of the paraventricular nucleus on the water and salt intake, renal excretion, and arterial pressure induced by angiotensin II injection into the medial septal area

In this study we investigated the influence of cu-adrenergic antagonists injections into the paraventricular nucleus (PVN) of the hypothalamus on the thirst and salt appetite, diuresis, natriuresis, and presser effects of angiotensin II (ANG II) stimulation of medial septal area (MSA). ANG II injection into the MSA induced water and sodium intake, diuresis, natriuresis, and presser responses. The previous injection of prazosin (an alpha (1)-adrenergic antagonist) into the PVN abolished, whereas previous administration of yohimbine (an alpha (2)-adrenergic antagonist) into the PVN increased the water and sodium intake, urinary, natriuretic, and presser responses induced by ANG ii injected into the MSA. Previous injection of a nonselective alpha -adrenergic antagonist, regitin, into the PVN blocked the urinary excretion, and reduced the water and sodium intake, sodium intake, and presser responses induced by ANG II injected into the MSA. The present results suggest that alpha -adrenergic pathways involving the PVN are important for the water and sodium excretion, urine and sodium excretion, and presser responses, induced by angiotensinergic activation of the MSA. (C) 2001 Elsevier B.V.

Ischaemia and reperfusion effects on skeletal muscle tissue: morphological and histochemical studies

This was a study on the oxidative stress due to ischaemia (I) and reperfusion (R) in skeletal muscle tissue. Using a tourniquet, groups of rats were submitted to ischaemia for 4 h, followed by different reperfusion periods. The animals were divided in four groups: control; 4 h of ischaemia (IR); 4 h of ischaemia plus 1 h reperfusion (IR-1 h); 4 h of ischaemia plus 24 h reperfusion (IR-24 h); and 4 h of ischaemia plus 72 h reperfusion (IR-72 h). At the end of the procedures, samples of soleus muscle were collected and frozen in n-hexane at -70 degrees C. Cryostat sections were submitted to haematoxylin-eosin, succinate dehydrogenase (SDH) and nicotinamide adenine dinucleotide-tetrazolium reductase (NADH-TR) stains. An additional muscle sample was processed for electron microscopy. No alterations were found in control animals. IR group showed fibres had normal aspect besides some round, acidophilic and hypertrophic fibres. There were several fibres with angular outlines and smaller diameters in this group compared with control group. NADH-TR/SDH reaction was moderately intense in most fibres. In some fibres, cytoplasm showed areas without activity and other fibres had very intense reactivity. IR-1 h group showed oedema hypercontracted fibres with disorganized myofibrils, mitochondria with focal lesions and dilated sarcoplasmic reticulum. NADH-TR/SDH reaction was moderate to weak. IR-24 h showed intense inflammatory infiltrate in the endomysium and perimysium. NADH-TR/SDH reaction was similar to IR-1 h. IR-72 h showed necrotic fibres, areas with inflammatory infiltrate, reduced muscle fibres at different stages of necrosis and phagocytosis, and many small round and basophilic fibres characterizing a regeneration process. NADH-TR/SDH reaction was weak to negative. Our results suggest that ischaemia and the subsequent 1-, 24- and 72-h reperfusions induced progressive histological damage. Although progressive, it may be reversible because there were ultrastructural signs of recovery after 72-h reperfusion. This recovery could in part be due to the low oxidative stress identified by the morphological and histochemical analysis.

Avaliação de dois modelos experimentais de isquemia e reperfusão cerebral em ratos com oclusão temporária carotídea associada ou não à oclusão vertebral

OBJETIVO: Avaliar a reprodutibilidade de dois modelos experimentais de isquemia e reperfusão cerebral. MÉTODOS: 60 ratos foram distribuídos, aleatoriamente, em três grupos experimentais, com 20 animais cada: I - pinçamento temporário de artéria carótida esquerda; II - cauterização prévia das artérias vertebrais e pinçamento temporário da artéria carótida esquerda; simulado - sem isquemia nem reperfusão. Todos os animais tiveram oclusão definitiva de artéria carótida direita e os três grupos foram subdivididos em dois períodos de reperfusão: A - 60 minutos e B - 120 minutos. Os parâmetros verificados foram: medidas de pressão arterial média sistêmica e fluxo sangüíneo carotídeo; medida de malondialdeído cerebral através do teste TBARS e avaliação histológica do hemisfério cerebral submetido à isquemia e reperfusão. Foi feito também um estudo complementar com angiografia cerebral em 5 animais adicionais. RESULTADOS: Não houve diferenças significativas nas dosagens de malondialdeído cerebral e na freqüência e gravidade das alterações histológicas cerebrais entre os três grupos. Nos grupos GI e GII, a PAM foi significantemente maior no período de isquemia. O fluxo sangüíneo entre os períodos pré e pós-pinçamento aumentou nos grupos IA e IIB, diminuiu no grupo IB e no grupo IIA manteve-se inalterado. As angiografias do estudo complementar mostraram aporte sangüíneo para cérebro através de circulação colateral. CONCLUSÃO: Os modelos de isquemia e reperfusão estudados não demonstraram alterações consistentes de marcadores de lesão cerebral, seja quanto à produção de lipoperóxidos ou de lesões histológicas.

Is coronary sinus blood oxygen tension behavior determined by myocardial oxygen tension variation during cardiac reperfusion?

The relationship between coronary sinus blood oxygen tension (CSPO 2) and myocardial oxygen tension (MPO 2) variations during cardiac ischemia and reperfusion was studied in anesthetized open-chest dogs. Oxygen tension was measured by a polarographic method. Ischemia resulted in a slightly decreased CSPO 2 and a more pronounced reduction of MPO 2. After reperfusion the CSPO 2 rose rapidly and transiently before it returned gradually to the control level. By contrast, during the recovery period, the MPO 2 increased slowly, with recovery occurring long after the peak of CSPO 2. These data suggest that during the reperfusion phase, the CSPO 2 variation is probably due to opening of the myocardial arteriovenous shunts instead of an increase of flow through the myocardial capillary bed.

Efeitos do alopurinol em rins isquemicos de caes anestesiados com pentobarbital sodico

Background and Objectives - Allopurinol is a drug which inhibits the formation of noxious renal free radicals. The aim of this study was to evaluate the protecting renal effects of allopurinol in ischemic kidneys of dogs. Methods - Sixteen dogs were anesthetized with sodium pentobarbital and submitted to extracellular volume expansion (1.4 ml.kg-1.min-1), to mechanic ventilation with air, to right nephrectomy and to left renal artery clamping. Changes which might occur in renal morphology and function after 30 min of total ischemia and posterior reperfusion were studied in Group 1 (G1), in addition to the action of allopurinol (50 mg.kg-1) on those kidneys, when administered 24 h before the experiment and 1 h before the ischemic procedure in Group 2 (G2). The following parameters: heart rate, inferior vena cava pressure, mean blood pressure, PAH clearance (PAH(c)), renal blood flow (RBF), renal vascular resistance (RVR), creatinine clearance (Cr(c)), filtration fraction, urine output, plasma and urine osmolality, osmolar clearance, free water, sodium and potassium clearance, urine and fractional sodium and potassium excretion, hematocrit, rectal temperature, and left kidney histology were evaluated in four moments: M1 control, and M2, M3, M4 obtained immediately, 15 and 30 min after unclamping of the left renal artery. In G2, M1, M2, M3 and M4 were obtained 45, 90, 105, and 120 min after the second allopurinol dose. Results - Both groups showed the highest values for PAH(c), RBF, and Cr(c), and the lowest values for RVR in M1. Animals were tachycardiac since the beginning of the experiment both in G1 and in G2. The other parameters were not changed. Left kidney histological evaluation showed alterations compatible with acute tubular necrosis in both experimental groups. Conclusions - Alterations found in renal hemodynamics were compatible with the release of vasoconstrictor substances due to renal ischemia. Allopurinol was not effective in preventing renal alterations caused by ischemia and reperfusion.

Lesões intestinais decorrentes de isquemia e reperfusão: Fisiopatologia e modelos experimentais

The intestinal ischemia is unusual in vascular surgery emergency. Its main causes are embolisms and arterial thrombosis. In addition to severe ischemia, reperfusion of the ischemic tissues can lead to several complications that may worsen the ischemic lesion and produce a life threatening situation caused by systemic alterations. Intestinal tissue injuries due to ischemia and reperfusion have been demonstrated in clinical and experimental studies, in which pathophysiology and adequate treatment were also studied. The great variety of experimental models used and results achieved reflect the need for an intestinal ischemia and reperfusion experimental model that is simple, reproducible and consistent, in order to search for treatments that can reduce the damage caused by this situation. In this review, the main pathophysiologic aspects and the most used experimental models will be reviewed. Copyright © 2005 by Sociedade Brasileira de Angiologia e Cirurgia Vascular.

Estudo da ação do ácido trissódio-cálcio-dietileno-triaminopentaacético (CaNa3DTPA) nas lesões de isquemia-reperfusão em membro posterior de rato

Pós-graduação em Bases Gerais da Cirurgia - FMB

Ultrasound analysis of a canine patient with renal disease and chronic liver disease undergoing treatment with intravenous stem cells

With the improvement in quality of life of animals, it is increasingly frequent clinical care of elderly patients, which present renal disorders, including chronic renal failure. Recent studies report the use of stem cells to treat renal failure, which would improve the levels of urea and creatinine, and in renal ultrasound evaluation. With the present work, the idea is to report a case of ultrasonographic evaluation in a patient with chronic renal failure, liver disease and splenic nodule, which underwent stem cell therapy, where there was an improvement in the sonographic evaluation of part of the liver.

Undernutrition fetal programming: effects on kidney morphology, renal steroid and angiotensin receptors expression and urinary sodium excretion

Maternal undernutrition affects the foetal development, promoting renal alterations and adult hypertension. The present study investigates, in adult male rats, the effect of food restriction in utero on arterial blood pressure changes (AP), and its possible association with the number of nephrons, renal function and angiotensin II (AT1R/AT2R), glucocorticoid (GR) and mineralocorticoid (MCR) receptors expression. The daily food supply to pregnant rats was measured and one group (n=5) received normal quantity of food (NF) while the other group received 50% of that (FR50) (n=5). The AP was measured weekly. At 16 weeks of life, fractionator’s method was used to estimate glomeruli number in histological slices. The renal function was estimate by creatinine and lithium clearances. Blood and urine samples were collected to biochemical determination of creatinine, sodium, potassium and lithium. At 90th and 23rd days of life, kidneys were also processed to AT1R, AT2R, GR and MCR immunolocalization and for western blotting analysis. FR50 offspring shows a significant reduction in BW (FR50: 5.67 ± 0.16 vs. 6.84 ± 0.13g in NF, P<0.001) and increased AP from 6th to 12nd week (6thwk FR50: 149.1 ± 3.4 vs. 125.1 ± 3.2mmHg in NF, P<0.001and, 12ndwk FR50: 164.4 ± 4.9 vs. 144.0 ± 3.3 mmHg in NF, P=0.02). Expression of AT1R and AT2R were significantly decreased in FR50 (AT1, 59080 ± 2709 vs. 77000 ± 3591 in NF, P=0.05; AT2, 27500 ± 95.50 vs. 67870 ± 1509 in NF, P=0.001) while the expression of GR increased in FR50 (36090 ± 781.5 vs. 4446 ± 364.5 in NF, P=0.0007). The expression of MCR did not change significantly. We also verified a pronounced decrease in fractional urinary sodium excretion in FR50 offspring (0.03 ± 0.02 vs. 0.06 ± 0.04 in NF, p=0.03). This occurred despite unchanged creatinine clearance. The study led us to suggest that fetal undernutrition, with increased fetal exposure... (Complete abstract click electronic access below)

Avaliação do efeito do citral na dor neuropática e na inflamação

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparison of imaging methods for diagnosis of renal tumors and their calcifications

Background: To establish the best methodology for diagnosis and management of patients with solid and complex renal masses by comparing the costs and benefits of different imaging methods and to improve differential diagnosis of these benign and malignant lesions, particularly by investigating tumour calcifications. Methods: We performed a prospective study on 31 patients with solid or complex masses by submitting them to Abdominal Ultrasonography (US), Doppler Ultrasonography of the renal mass (US Dop), Computed Tomography (CT), and Magnetic Resonance Imaging (MRI). Results: We found 28 patients with malignant and three with benign masses. Of the 28 malignant, 17 showed calcifications at CT; 16 central and one was of the pure peripheral curvilinear type (egg shell). Excretory Urography (IVP) had a significantly lower detection rate for central calcifications than both US and CT. Benign and malignant masses appeared as described in literature, with US, CT and MRI showing high sensitivity and specificity in renal tumor diagnosis. The exception was US Dop where we obtained lower sensitivity for the characterization of malignant tumor flow. Conclusions: In this series we were surprised to find that CT revealed central calcifications in 51.6% of patients, all with malignant lesions, while, literature reports a frequency of calcification in renal cell carcinoma between 8 and 22%, in studies using abdominal films and EU (IVP). This finding is of great importance when we consider that these calcifications occur particularly in malignant neoplasms. As a result of comparing these different imaging methods we have developed a better methodology for renal tumor investigation.

Role of α1-, and α2- and β-adrenoceptors of the median preoptic area on the water intake, renal excretion, and arterial pressure induced by ANG II

The present experiments were conducted to investigate the role of the α1-, α2- and β-adrenergic receptors of the median preoptic area (MnPO) on the water intake and urinary electrolyte excretion, elicited by central injections of angiotensin II (ANG II). Prazosin (an α1-adrenergic receptor antagonist) and yohimbine (an α2-adrenergic receptor antagonist) antagonized the water ingestion, Na +, K +, and urine excretion induced by ANG II. Administration of propranolol, a β-adrenergic receptor antagonist increased the Na +, K +, and urine excretion induced by ANG II. Previous treatment with prazosin and yohimbine reduced the pressor responses to ANG II. These results suggest that the adrenergic neurotransmission in the MnPO may actively participate in ANG II-induced dipsogenesis, natriuresis, kaliuresis, diuresis and pressor responses in a process that involves α1-, α2-, and β-adrenoceptors.

Alterações ultraestruturais nas vilosidades do jejuno de equinos após distensão

O objetivo do presente estudo foi analisar as alterações ultraestruturais nas vilosidades do jejuno de seis equinos submetidos à distensão intraluminal com solução salina. A pressão intraluminal foi mantida em 25cm de água durante duas horas. As amostras de mucosa intestinal colhidas às: zero hora; duas horas de distensão; e duas horas e 12h de descompressão foram analisadas por meio de microscopia eletrônica de varredura. Avaliaram-se a área e o perímetro das vilosidades e sua densidade, usando-se um programa computacional de análise de imagens (Image J). A distensão luminal promoveu aumentos da área e do perímetro das vilosidades intestinais. Essa alteração ultraestrutural ocorreu somente 12h após a descompressão e considerou-se que a provável causa seria o edema promovido por aumento da permeabilidade vascular decorrente de um processo de isquemia e reperfusão da mucosa intestinal. Concluiu-se que a distensão intraluminal do jejuno equino promoveu, tardiamente, aumento das dimensões das vilosidades intestinais.

Efeito do geraniol sobre a doença ulcerosa péptica experimental

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)