جستجوی مقالات مرتبط با کلیدواژه « پرفیوژن » در نشریات گروه « پزشکی »

The isolated perfused rat liver is an accepted method in toxicology studies. The isolated perfused rat liver (IPRL) is a useful experimental system for evaluating hepatic function without the influence of other organ systems، undefined plasma constituents، and neural-hormonal effects. The untreated male rats (180-220gr body weight) were anesthetised with ether and then surgery with proper method. The abdomen was opened through a midline and one transversal incision and the bile duct was cannulated. Heparin sodium solution (0. 5 ml; 500 U/ml in 0. 9% NaCl) was injected via the abdominal vena cava to prevent blood clotting. The liver inferior venacava was cannulated with PE-10 tubing and secured. The portal vein was immediately cannulated with an 23gr catheter which was secured and then liver was perfused in situ by Krebs- Henseleit buffer (pH 7. 4; saturated with 95% O2 and 5% CO2; 37°C) at a flow rate of 20 ml/min for 3hr. Temperature، perfusion pressure، flow rate and perfusion fluid pH were closely monitored during the perfusion. Transferase enzymes (ALT، AST) alterations can be widely used as a measure of biochemical alterations in order to assess liver damage due to use of drugs such as isoniazid (INH) and animal and plant toxins. Accumulated material in gallbladder are valuable samples to assess the level of Glutathione (GSH). Sections of perfused liver tissue can also be effectively analyzed for pathological aspects such as necrosis، fibrosis، cellularity. The isolated perfused rat liver (IPRL) is a useful and Sutible experimental system for evaluating hepatic function. In this system، the effects of adjacent organs، on the liver is minimized.

In recent years, the role of reactive oxygen species (ROS) in ischemia-reperfusion injury (IRI) is established and different methods including ischemic preconditioning and postconditioning (POC) are introduced to reduce the damage. One of the possible protective mechanisms of POC is a reduction in ROS formation. According to the significance and prevalence of renal IRI, in the present study, the protective effect of POC on the reduction of IR-induced renal injury was evaluated. After right nephrectomy, male Sprague-Dawley rats were randomly assigned into three groups (n= 6). In IR group, with the use of bulldog clamp 45 min of left renal artery was induced followed by 24 hours of reperfusion. In sham group, all of the above surgical procedures were applied except that IR was not induced. In POC group, after induction of 45 min ischemia, 4 cycles of 10 seconds of intermittent ischemia and reperfusion were applied before restoring of blood to the kidney. At the end of the experiments, serum and renal tissue samples were collected for renal functional monitoring and oxidative stress evaluation. POC prevented the IR-induced increase in blood urea Nitrogen and serum creatinine and improved the kidney oxidative status demonstrated by a decrease in malondialdehyde level and an increase in superoxide dismutase. ‍ POC has a protective role on renal function by a reduction in IR-induced oxidative stress.

Cardiopulmonary bypass often causes a stress hormonal response with subsequent changes in hemodynamic and organ perfusion. Human studies involving cardiopulmonary bypass have shown that very low doses of ketamine can attenuate inflammatory and stress markers, without adverse effects. The aim of this study was to investigate whether low dose infusion of ketamine have hemodynamic stability effect in coronary artery bypass surgery.

In this double blind-controlled trial, 50 patients undergoing on-pump CABG were randomly assigned to receive either 1.25mcg/kg/min of ketamine infusion (Ketamine group, n=25) or normal saline infusion (Control group, n=25) during 48 hours after induction of anesthesia. hemodynamic measurement including blood pressure, heart rate, central venous pressure, cardiac output, cardiac index, systemic venous resistance, arterial blood gas and lactate were measured previous to induction (T1), 4 h, 24h, and48h after the surgery (T2,T3 and T4). The data were evaluated with using of variance analyzing test and repeated measurement.

There were significant interaction effect between time (pre operation, 4, 24 and 48 hours after operation) and group of study (ketamine and placebo) in assessment of systolic blood pressure (p=0.0001), diastolic blood pressure(p=0.0001), heart rate (p=0.004), central venous pressure (p=0.0001) and lactate (p=0.035). These indicate that ketamine caused decrement in tissue perfusion. Those interactions were not statistically significant for other parameters (p>0.05).

low dose ketamine during and 48 hours after operation not only didn`t show hemodynamic stability effect but also decreased tissue perfusion slightly.

Co-administration of cyclosporine and erythromycin can cause nephrotoxicity which could be a result of interaction in absorption and/or metabolism level. The purpose of this work was to investigate the interaction of erythromycin and cyclosporine in absorption level to evaluate the effect of erythromycin on cyclosporine absorption quantitatively. The stability of drug at 37°C and its adsorption to plastic syringe and tubes were also investigated. 32 Wistar rats weighting between 200-300 g were used in the present study. They were divided into 4 test groups and 4 control groups. A jejunal segment of anaesthetized rat was cannulated and perfused by concentrations of 20, 15, 10 and 5 micromolar of drug in the presence and absence of 150 micromolar erythromycin by flow rate of 0.2 ml/min. Samples were obtained up to 90 min. Drug concentrations were assayed in different time points. The drug effective permeability values were calculated for its different concentrations in different experiments. A reverse-phase HPLC method was used for analysis of all samples. The cyclosporine effective permeability values were increased from 22.1-33.4 (10-6) cm/sec in control group to 37.2-53.4 (10-6) cm/sec in test group that this difference was significant (p<0.05). Moreover cyclosporine was stable and only 4-5% loss of drug was observed at the end of experiment. However there was a significant adsorption of drug to syringe and tubing. Based on obtained results cyclosporine is a low solubility and high permeability drug. At least some part of clinical interaction between cyclosporine and erythromycin is due to interaction in absorption level.

Background and

Perfused rat liver and isolated hepatocytes are useful to study specific metabolism of this organ. Traditionally, mechanical, chemical and enzymatic methods have been used to isolate hepatocytes, and it appears that a mixed method is the preferred choice.

The rat liver perfused in situe in three subsequent steps, 10 minutes with Krebs-Ringer solution containing ethylene diamine tetra-acetic acid (EDTA, 2mM) without calcium and magnesium, and 1 minute with the same solution, however, without EDTA in open non-recirculatory pathway. This followed by 10 minutes with Krebs-Ringer solution, containing collagenase (200 IU/mL) in closed recirculatory system. The hepatocytes were isolated, collected and incubated (6-8 × 106 cells/mL) for 3-hours in Krebs-Ringer solution, under the atmosphere of O2:CO2 (95:5). The cell viability was assessed with tripan blue exclusion and lactate dehydrogenase (LDH) leakage.

Assay of LDH activity, the marker of cytosolic enzyme, show that more than 92% and 88% of the enzyme had been retained in the cells, with less than 8% and 12% leakage from the damaged cells in the beginning and end of incubation, respectively. Microscopic evaluation showed that the majority of the cells had intact plasma membrane without vacuoles. When the cells were stained with dye, less than 5% of vital dye included these cells.

The results showed that perfusion of the rat liver with the solution containing calcium chealator and collagenase can yield about 10 mL of hepatocytes with a viability of more than 90%.

Phytolacca americana is a native plant in several states of USA and mostly its boiled leaves are used as a popular salad (called grandmother salad) in American diet. It grows widely in the coastal areas and forests in northern parts of Iran but is rarely used. In spite of having several medicinal properties, its side effect is digestive toxicity (especially hepatotoxicity). To date, the hepathotoxicity of this plant from northern of Iran has not been studied. Therefore, this study was aimed to investigate the hepatotoxicity of P. americana using Isolated Rat Liver Perfusion (IRLP) system. The albino rats weighted 180-220 g were desighdted into 6 groups. Subsequently, the male rat’s anesthetized using ether, were used for experiments. The inferior vena cava was cannnulated with PE-10 tubing. The portal vein was immediately cannulated with a 23 g catheter. Then the liver was perfused in site by Krebs-Henseleit buffer at 37°C with a rate of 20ml/min for 3hr. After 30-45 min of perfusion, various doses (10, 20, 40, 50, 100 mg/kg) of aqueous and methanol extracts and CHCl3, ETOAC & MEOH fraction (10, 20, 40mg/kg) were added to the buffer and perfused for 2 hr. Samples of perfused fluid were collected every 30min and analyzed for any liver injury by measuring the serum enzymes (ALT, AST). Sections of liver tissue were also examined for pathological changes. The results showed that the activity of aminotransferase enzymes increased significantly and dose-dependently (p<0.01). Also, methanol extract fractionates were increased compared with the control group (p<0.05). The histopathological changes in the liver tissue were dose-dependent and confirmed the previous data. The enzymatic differences between the test groups and the control group showed the most difference at 60 min. The finding showed that the hepatotoxic effect of P. americana is dose dependent. Therefore, decreasing the administrated dose may be effective in prevention of its hepatic side effects.