Role of cholinergic and adrenergic pathways of the medial septal area in the control of water intake and renal excretion in rats

In this study, we investigated an interaction between noradrenergic and cholinergic pathways of the medial septal area (MSA) on the control of water intake and urinary electrolyte excretion by means of injection of their respective agonists. Noradrenaline (a nonspecific α-adrenergic agonist) and clonidine (an α2-adrenergic agonist), but not phenylephrine (an α1-adrenergic agonist), induced natriuresis and kaliuresis. α-Adrenergic activation had no effect on the natriuresis and kaliuresis induced by carbachol (a cholinergic agonist) and it inhibited the antinatriuresis and antikaliuresis induced by isoproterenol (a ß-adrenergic agonist). Interactions related to volume excretion are complex. α-Adrenergic activation induced a mild diuresis and inhibited the antidiuresis induced by isoproterenol, but phenylephrine combined with carbachol induced antidiuresis. The water intake induced by carbachol was inhibited by clonidine and noradrenaline, but not phenylephrine. These results show an asymmetry in the interaction between α-adrenergic and cholinergic receptors concerning water intake and electrolyte excretion. © 1992.

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.

Greater level of physical activity associated with better cognitive function in hemodialysis in end stage renal disease

Patients with chronic kidney disease (CKD) have a lower exercise tolerance and poor functional capacity, carry on a sedentary lifestyle. Another important change found in patients with CKD is cognitive dysfunction. Physical inactivity has been associated with cognitive dysfunction in the general population, but few studies have evaluated this association in CKD. To assess the association between physical activity and cognitive function in patients with CKD on hemodialysis (HD). We evaluated 102 patients undergoing HD. The participants completed the International Physical Activity Questionnaire, which assesses the level of physical activity and the Mini Mental State Examination, used for cognitive screening. Patients were divided into three groups according to their level of physical activity (GI: active/GII: irregularly active/GIII: sedentary). It was applied logistic regression analysis and adopted as outcome variable the presence of cognitive impairment and preserving as independent variables those with a probability of statistical difference between groups of less than 0.1. It was considered statistically significant when p less than 0.05. The groups were similar in age, duration of HD, and smoking. Statistically significant difference regarding race, body mass index, diabetes mellitus, underlying disease and degree of cognitive impairment. Regarding laboratory data, the groups differed in terms of creatinine, glucose, hemoglobin and hematocrit. There was significant association with better physical activity and cognitive function, even adjusting for confounding variables. the highest level of physical activity was associated with better cognitive function in CKD patients undergoing HD.

Norepinephrine responses in rat renal and femoral veins are reinforced by vasoconstrictor prostanoids

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

Behavioral measures to reduce non-adherence in renal transplant recipients: a prospective randomized controlled trial

Solid-organ transplant recipients present a high rate of non-adherence to drug treatment. Few interventional studies have included approaches aimed at increasing adherence. The objective of this study was to evaluate the impact of an educational and behavioral strategy on treatment adherence of kidney transplant recipients. In a randomized prospective study, incident renal transplant patients (n = 111) were divided into two groups: control group (received usual transplant patient education) and treatment group (usual transplant patient education plus ten additional weekly 30-min education/counseling sessions about immunosuppressive drugs and behavioral changes). Treatment adherence was assessed using ITAS adherence questionnaire after 3 months. Renal function at 3, 6, and 12 months, and the incidence of transplant rejection were evaluated. The non-adherence rates were 46.4 and 14.5 % in the control and treatment groups (p = 0.001), respectively. The relative risk for non-adherence was 2.59 times (CI 1.38-4.88) higher in the control group. Multivariate analysis demonstrated a 5.84 times (CI 1.8-18.8, p = 0.003) higher risk of non-adherence in the control group. There were no differences in renal function and rejection rates between groups. A behavioral and educational strategy addressing the patient's perceptions and knowledge about the anti-rejection drugs significantly improved the short-term adherence to immunosuppressive therapy.

Ischemic postconditioning and subanesthetic S(+)-Ketamine infusion: effects on renal function and histology in rats

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

l-amino acid oxidase from Bothrops marajoensis causes nephrotoxicity in isolated perfused kidney and cytotoxicity in MDCK renal cells

Renal alterations caused by Bothrops venom and its compounds are studied to understand these effects and provide the best treatment. Previously, we studied the renal effect of the whole venom of Bothrops marajoensis and its phospholipase A2 (PLA2), but these effects could not to be attributed to PLA2. To continue the study, we report in this short communication the effects of l-amino acid oxidase from B. marajoensis venom (LAAOBm) on renal function parameter alterations observed in the same model of isolated perfused kidney, as well as the cytotoxic effect on renal cells. LAAOBm caused a decrease in PP, RVR, UF, GFR, %TNa(+) and %TCl(-), very similar to the effects of whole venom using the same model. We also demonstrated its cytotoxicity in MDCK cells with IC50 of 2.5 μg/mL and late apoptotic involvement demonstrated by flow cytometry assays. In conclusion, we suggested that LAAOBm is a nephrotoxic compound of B. marajoensis venom.

Bothropoides pauloensis venom effects on isolated perfused kidney and cultured renal tubular epithelial cells

Coordenadação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos da ciclosporina na lesão renal por isquemia-reperfusão em ratos: estudo em modelo experimental

Pós-graduação em Anestesiologia - FMB

Seguimento nutricional de pacientes após episódios de lesão renal aguda e identificação de fatores de riscos nuricionais para o óbito tardio

Pós-graduação em Fisiopatologia em Clínica Médica - FMB

Vivenciar a doença: um estudo com portadores de doença renal crônica

Pós-graduação em Saúde Coletiva - FMB

TNF-alpha and IL-6 immunohistochemistry in rat renal tissue experimentaly infected with Leptospira interrogans serovar Canicola

Leptospirosis is a public health problem worldwide and its etiology remains unclear. Its pathogenesis involves a complex interaction between host and infecting microorganism. The inflammatory reaction that controls the infection process also underscores many pathophysiological events occurring in leptospirosis. We investigated the presence of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in renal tissues by immunohistochemical and histopathological examination in animals experimentally inoculated with Leptospira serovar Canicola. All the tests were carried out 2, 7, 14, 21 or 28 days after inoculation. Although TNF-alpha and IL-6 had been detected in tissues throughout the observation period, these cytokines appeared more intensely during the initial phase of infection. Therefore, both TNF-alpha and IL-6 were associated with the immunopathogenesis of leptospirosis. This profile suggests a high immunocellular response throughout the early infection stages followed by subsequent humoral response.

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.

Efeito do soro de cães portadores de insuficiência renal sobre a apoptose e o metabolismo oxidativo dos polimorfonucleares

In recent years, uremic toxins have been widely investigated as an immunosuppressive factor for nephropathic patients. This study aimed to test the hypothesis that, as it was similarly observed in humans, the rate of apoptosis and superoxide production in polymorphonuclear leukocytes are changed in dogs treated with uremic serum. The superoxide production of polymorphonuclear leukocytes and apoptotic index of 10 healthy dogs incubated with autologous and homologous serum from healthy and uremic dogs was compared. Thus, there was an effect of partial inhibition of oxidative metabolism in uremia without correlation with the acceleration of polymorphonuclear leukocytes apoptosis in dogs.

Morphological, immunohistochemical and molecular study of renal lesions in canine visceral leishmaniasis (CVL)

Canine visceral leishmaniasis (CVL) is an anthropozoonosis characterized by a clinically chronic progressive disease. Non lymphoid organs are also affected, especially the kidneys. Dogs with leishmaniasis usually die with renal failure despite treatment. Haematoxylin-eosin (HE) staining in kidney tissue sections has low sensitivity for parasite identification. Immunohistochemistry (IHC) and polymerase chain reaction (PCR) are efficient methods for Leishmania sp. antigen and DNA detection in cases of low parasite burden. The present study aims to identify renal lesions of CVL and correlate them with microscopic findings determined by histochemistry, IHC and PCR. Both IHC and PCR provided similar positivity for amastigote identification, 3/20 animals (15%), thus increasing detection of the parasite in renal tissues when compared with histopathologic examination. The lesion most commonly observed with visceral leishmaniasis-positive canine kidney tissue was membranoproliferative glomerulonephritis, followed by interstitial nephritis without correlation to the number of amastigotes.