Role of Mas receptor antagonist (A779) in renal hemodynamics in condition of blocked angiotensin II receptors in rats

The vasodilatory effect of angiotensin 1–7 (Ang 1-7) is exerted in the vascular bed via Mas receptor (MasR) gender dependently. However, the crosstalk between MasR and angiotensin II (Ang II) types 1 and 2 receptors (AT1R and AT2R) may change some actions of Ang 1-7 in renal circulation. In this study by blocking AT1R and AT2R, the role of MasR in kidney hemodynamics was described. In anaesthetized male and female Wistar rats, the effects of saline as vehicle and MasR blockade (A779) were tested on mean arterial pressure (MAP), renal perfusion pressure (RPP), renal blood flow (RBF), and renal vascular resistance (RVR) when both AT1R and AT2R were blocked by losartan and PD123319, respectively. In male rats, when AT1R and AT2R were blocked, there was a tendency for the increase in RBF/wet kidney tissue weight (RBF/KW) to be elevated by A779 as compared with the vehicle (P=0.08), and this was not the case in female rats. The impact of MasR on renal hemodynamics appears not to be sexual dimorphism either when Ang II receptors were blocked. It seems that co-blockade of all AT1R, AT2R, and MasR may alter RBF/ KW in male more than in female rats. These findings support a crosstalk between MasR and Ang II receptors in renal circulation

Context Driven Concept Based Image Retrieval

Several semantic image search schemes have been recently proposed to retrieve images from the web. However, the query context is regularly ignored in these techniques and hence, many of the returned images are not adequately relevant. In this paper, we make use of context to further confine the outcome of the semantic search engines. For this purpose, we propose a hybrid search engine which utilizes concept and context for retrieving precise results. In the proposed model, an ontology is exploited for annotating images and accomplishing search process in the semantic level. Furthermore, the query of the user is modified with the concepts available in the ontology. Next, we make use of search context of the user and augment the query with the information extracted from the user’s context to additionally eliminate irrelevant results. Experimental results show that the combination of concept and context is effective in retrieving and presenting the most relevant results to the user

The effect of the various doses of atorvastatin on renal tubular cells; an experimental study

Recent retrospective observational studies suggest that high-potency statin therapy might increase the risk of acute kidney injury, however data on this subject is scares. Objectives: This study, was designed to investigate the renal tubular cell effect of different doses of atorvastatin to detect the possible aggravation of renal function or morphology of the kidney. Materials and Methods: In this experimental study 24 male Wistar rats were designated into 4 equal groups and treated as follows. Control group received phosphate buffer as the vehicle of atorvastatin for 7 days. Groups 1, II and III received atorvastatin at doses of 10, 50 and 150 mg/kg daily for 7 days, then on the day 8, all rats were anesthetized using ketamine and the blood samples were collected for evaluation of creatinine (Cr) and blood urea nitrogen (BUN) levels and then all rats were sacrificed, then the animals’ kidneys were dissected out and histopathological studies were performed Results: Mean (±SD) of scores of injury to renal tubular cells in control group was 4.2 ±2.2 and in groups I, II and III were 6.44 ± 4.9, 15.4± 8.5 and 25.8 ± 12.7 respectively. Group III which received 150 mg/kg/day of atorvastatin had significant renal damage in comparison to control group (P < 0.001). There was no significant difference of renal injury score between control group with groups of I and II. Conclusions: In the present study we found, atorvastatin with a dose of 150 mg/kg/day for 7 days was nephrotoxic for rats, while lower doses at 10 mg/kg/day or 50 mg/kg/day for 7 days were not accompanied by renal injury. These findings imply further attention to the administration of higher doses of atorvastatin in clinical conditions

Ameliorative effects of metformin on renal histologic and biochemical alterations of gentamicin-induced renal toxicity in Wistar rats

Background: The aim of this study was to test the potential properties of metformin (MF) to protect the kidney from gentamicin (GM)-induced renal toxicity. Materials and Methods: In this preclinical study, 50 male Wistar rats were randomly divided into five groups of 10 rats in each. In the first group (group I), they were kept in the same condition as others without receiving drugs for 10 days. In group II, the rats were injected intraperitoneally with 100 mg/kg/day of GM for 10 consecutive days. Group III rats received 100 mg/kg/day MF orally for 10 days. In group IV, the rats received GM (100 mg/kg; intraperitoneally) for 10 days and 100 mg/kg/day MF orally for the next 10 days. In the last group (group V), the rats received a combination of GM 100 mg/kg/day intraperitoneally and MF 100 mg/kg/day orally for 10 days simultaneously. Serum blood urea nitrogen (BUN) and creatinine (Cr) values were measured and renal tissues of the animals were processed for light microscope examination. Results: The levels of BUN in groups II, IV, and V, and also the serum level of Cr in groups II and V were increased significantly after the experiment. Furthermore, post-treatment with MF or co-treatment with MF could prevent the elevation of serum BUN and Cr induced by GM and also attenuates the damage score (P < 0.05). Conclusions: MF may prevent or ameliorate GM-induced acute renal failure, and therefore it might be beneficial in patients under treatment with this medicine

Improving the efficiency of term weighting in set of dynamic documents

In real information systems, there are few static documents. On the other hand, there are too many documents that their content change during the time that could be considered as signals to improve the quality of information retrieval. Unfortunately, considering all these changes could be time-consuming. In this paper, a method has been proposed that the time of analyzing these changes could be reduced significantly. The main idea of this method is choosing a special part of changes that do not make effective changes in the quality of information retrieval; but it could be possible to reduce the analyzing time. To evaluate the proposed method, three different datasets selected from Wikipedia. Different factors have been assessed in term weighting and the effect of the proposed method investigated on these factors. The results of empirical experiments showed that the proposed method could keep the quality of retrieved information in an acceptable rate and reduce the documents\u2018 analysis time as a result

Interference-aware multipath routing protocol for QoS improvement in event-driven wireless sensor networks

The existing multipath routing protocols for wireless sensor networks demonstrate the efficacy of traffic distribution over multiple paths to fulfill the Quality of Service (QoS) requirements of different applications. However, the performance of these protocols is highly affected by the characteristics of the wireless channel and may be even inferior to the performance of single-path approaches. Specifically, when multiple adjacent paths are being used concurrently, the broadcast nature of wireless channels results in interpath interference which significantly degrades end-to-end throughput. In this paper, we propose a Low-Interference Energy-efficient Multipath Routing protocol (LIEMRO) to improve the QoS requirements of event-driven applications. In addition, in order to optimize resource utilization over the established paths, LIEMRO employs a quality-based load balancing algorithm to regulate the amount of traffic injected into the paths. The performance gain of LIEMRO compared to the ETX-based single-path routing protocol is 85, 80, and 25 in terms of data delivery ratio, end-to-end throughput, and network lifetime, respectively. Furthermore, the end-to-end latency is improved more than 60

Role of bradykinin and mas receptor blockade in renal vascular responses to angiotensin 1-7 in adult female rats

Background and purpose: Chronic kidney disease is among the common diseases in the world. Studies show that women are more protected against renal diseases compared to men. On the other hand, vasodilatory axises of renin angiotensin system (angiotensin 1-7 (Ang 1-7)-Mas receptor (MasR)), kallikrein-kinin, and nitric oxide (NO) play key roles in kidney function and circulation in females. Therefore, the purpose of this study was to examine the effect of bradykinin in renal blood flow (RBF) response to Ang 1-7 when MasR was blocked in female rats. Materials and methods: Female Wistar rats were divided into three groups (control, Bradykinine, and Bradykinin + MasR antagonist (A779)). The animals were anesthetized and catheterized in the carotid and femoral arteries and jugular vein to measure mean arterial pressure (MAP), renal perfusion pressure (RPP), and drug administration, respectively. The left kidney was exposed (in situ) and placed in a kidney cup to measure RBF. After the equilibration period, A779 and bradykinin (50 μg/kg/h, 150 μg/kg/h, respectively) were injected and vascular responses to Ang1-7 (100, 300, and 1000 ng kg�1min�1) infusion were determined. At the end of the experiment, blood samples were collected for measuring the level of nitrite. Results: The MAP and RPP were not significantly different between the three groups. Bradykinin exhibited vasodilatory effect on RBF in response to Ang 1-7 in female rats, however, A779 administration increased RBF at low dose of Ang 1-7(Pdose=0.001). The serum level of nitrite significantly decreased when the MasR was blocked (P= 0.04). Conclusion: Bradykinin enhanced RBF response to Ang 1-7 infusion. The effect of bradykinin on RBF response to Ang 1-7 may be modulated via the NO pathway. Interaction of these factors might help to broaden our vision for treatment strategy in future. © 2020, Mazandaran University of Medical Sciences. All rights reserved

Angiotensin 1-7 administration increases renal blood flow in the absence of bradykinin B2 receptor in ovariectomized estradiol treated rats: The role of mas receptor

Renin angiotensin (RAS), kallikrein kinin (KKS), and sex hormonal systems demonstrate a complex contribution in kidney circulation. This study was designed to investigate the role of angiotensin 1-7 (Ang 1-7) receptor (MasR) and of bradykinin B2 receptor (B2R) in renal blood flow (RBF) response to Ang 1-7 infusion in ovariectomized estradiol treated rats. The ovariectomized rats received intramuscular vehicle (group 1, OV) or estradiol valerate (500 µg/Kg/week) (group 2, OVE) for two weeks. Then each group was divided into two subgroups subjected to receive B2R antagonist (HOE-140, subgroup A), or MasR antagonist (A779) plus HOE-140 (subgroup B). RBF and renal vascular resistance (RVR) responses to graded Ang 1-7 infusion were determined. In condition of B2R alone blocking, RBF response to Ang 1-7 in OVE group was significantly greater than that of OV group (P=0.05), however this response difference was failed by co-blockades of MasR and B2R. Estradiol could promote RBF response to graded Ang 1-7 infusion in the absence of B2R alone, however when both receptors (MasR and B2R) were blocked the role of estradiol was limited

Antioxidant activity and preventive effect of aqueous leaf extract of Aloe Vera on gentamicin-induced nephrotoxicity in male Wistar rats

Objective(s): In the present study, the nephroprotective and curative effects of aqueous extract of AV on gentamicin-induced tubular toxicity in male Wistar rats were investigated. Antioxidant activity, phenolic and flavonoid contents of AV were also determined. Materials and Methods: In a preclinical study, 60 male Wistar rats were designated into 6 groups of 10 and treated as follows: Group I: Treated with vehicle (distilled water) and kept as control. Group II: Received 300 mg/kg/d AV for three days then, AV plus GM (80 mg/kg; intraperitoneally) for 7 more days and sacrificed. Group III: Received 300 mg/kg AV orally for 10 days, then sacrificed. Group IV: Received GM for 7 days and sacrificed. Group V: Received GM for 7 days and saline for ten days and sacrificed on 17th day. Group VI: Received GM for 7 days, then AV for 10 days and sacrificed. Results: The levels of flavonoid and phenolic compounds in Aloe vera extract were 43±3.8 mg/g (Rutin equivalent) and 80.1±3.8 mg/g (Gallic acid equivalent), respectively. The antioxidant activity of the extract was 38. The intensity of nephrotoxicity in group 2 that received AV 300 mg/kg/d as prophylaxis was not significantly different from the group I and from the group II which treated with 300 mg/kg/d AV without GM. This finding reveals that AV as prophylaxis could potentially attenuate the GM-induced nephrotoxicity. Conclusion: Aole vera significantly protects the renal cells and reduces the severity of tubular damage caused by gentamicin. However, it cannot regenerate tubular damage. © Societá Editrice Universo (SEU)