فهرست مطالب وحید خوری

The aim of the present study was to use the Maillard reaction as a means to glycosylate protein hydrolysates obtained from Cajanus cajan and to evaluate the effects of this chemical modification on antioxidant and emulsifying properties. Chemical properties, amino acid composition, and molecular weight distribution of the hydrolysates were evaluated. Glucose, galactose, and maltodextrin in the ratios of 1:2, 1:1, and 2:1 (hydrolysate: sugar, dry weight basis) were used for glycosylation. Antioxidant activity was evaluated by 1, 1- diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and nitric oxide scavenging. The sonication technique was used to prepare the (oil/water) emulsions. The droplet size distribution and zeta potential of the emulsions were measured during 4 days of storage. Results showed that glycosylation by glucose in the ratio of 2:1 increased DPPH scavenging activity from 37.96% to 85.53% and nitric oxide inhibition activity from 14.50% to 54.83%. Although glycosylation improved emulsifying stability of glycosylated hydrolysates compared to non-glycosylated hydrolysates, no significant difference was observed between the three examined sugars.

Proteins are being hydrolyzed to generate various properties such as antioxidant activity and nutritional values. Enzymatic hydrolysis is carried out in milder condition and is more controllable. The produced protein hydrolysates’ properties are dependent to the hydrolysis condition. So by optimizing the hydrolysis conditions, proteins with higher antioxidant abilities are achieved. Response surface method is a statistical way to optimize and model the process more efficiently. The aim of present study was to optimize and model the hydrolysis condition to produce and antioxidant protein hydrolysate with high nutritional value   from Cajanus cajan by pepsin.

First, Cajanus cajan’s proteins solubility was measured. After reaching the pHs with the most and least solubility, protein extraction was carries out by using NaOH and HCl. Enzyme concentration (1, 2, 3%), temperature (30, 35, 40 °C) and time (2, 3.5, 5 h) as independent variables were given to the Design Expert software and protein hydrolysis was done in a shaker incubator according to the 20 treatments suggested by the software. 1, 1- diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, hydroxyl radical scavenging activity, Reducing power and total antioxidant activity were measured as dependent variables. Antioxidant assays were modeled by the software and the optimum condition was evaluated. The obtained optimum condition was validated by repeating the antioxidant assays for the protein hydrolysate produced in the optimum condition. The amino acid profile of the protein hydrolysate was measured using HPLC-MS and chemical score was measures. Then, the molecular weight distribution of the protein concentrate and protein hydrolysate was evaluated by FPLC. Chemical composition of the samples was also measured.

The optimum condition for achieving antioxidant protein hydrolysate was enzyme concentration 2.15%, temperature 39.99 °C and time 4.52 h. Model validation results for this point were including DPPH scavenging activity 58.49%, reducing power 0.31 nm, hydroxyl radical scavenging activity 38.2% and total antioxidant capacity 0.63 nm. The protein concentrate consisted of 215.84 mg/g hydrophobic and 57.04 mg/g of them were aromatic amino acids. These amino acids are responsible for antioxidant activity of the protein hydrolysates. Chemical scores for essential amino acids were good. Most of the peptides in the protein hydrolysate had molecular weights below 10 kD that is considered to have antioxidant activities. Hydrolysis also increased the protein and ash content while fat and water content decreased compared to the Cajanus cajan’s flour and protein concentrate. Results showed that Cajanus cajan’s protein hydrolysate can be a good source of antioxidants and play a positive role in human nutrition.

A brief and short duration episode of ischemia is recorded in ischemic preconditioning (IPC). This latter condition provides a status in which large region of heart is protected when prolonged ischemia occurred. Levothyroxine play a protective role in IPC induction, and simultaneously with stress oxidative. This study was conducted to determine the protective effect of levothyroxine with oxidative stress reduction mechanism in ischemic preconditioning model in rat heart.
This experimental study was performed on 30 male Wistar rats in three groups of 10, as follows. In the reperfusion ischaemia group (IR), the heart of the animal was placed in a Langendorff apparatus. In the ischemic preconditioning group (IPC), prior to major ischemia, was exposed to 4 periods of 5-minute ischemia with reperfusion. In the intraperitoneally administered group, levothyroxine at a dose of 25 microgram per 100 g of body weight, the heart was exposed to reperfusion ischemia. The area of infarct and the level of malondialdehyde in the heart tissue were measured.
The volume of Infarcted region in IR and IPC groups was 26.55 and 11.11 respectively. The same index for the Levothyroxine receiver was 12.56. Based on these findings it was demonstrated that Levothyroxine injection reduced the Infarcted region significantly similar with IPC (P Injection of levothyroxine with ischemic preconditioning reduced the effect of reperfusion maladaptive ischemia in rat heart.

Ventricular fibrillation is one of the main causes of sudden death. In order to evaluate the efficacy and mechanism of anti-arrhythmic drugs, various experimental models of arrhythmia have been developed. In the present study some in vitro models of ventricular arrhythmia in rat isolated heart are presented. Furthermore, efficacy of a smart ablation protocol to suppress ventricular rate is examined.

Five groups of 5 Wistar rats were used in this study. In group I, ventricular fibrillation (VF) was induced in the isolated heart by stepwise increased electrical stimulation (0-5 mA). In group II, VF was induced by stepwise increase in end diastolic pressure (25-100 mmHg). Group III (computerized VF model), computerized electrical stimulation was executed during 2 s in the range of 25-125 ms by AV node pack software. Group IV (hypokalemia-induced VF), VF was induced by diminution of potassium to 2.5-2.9mM in Krebs Henseleit solution. Group V, it was same as group III but smart ablation of the left ventricle was carried out by 110 volt DC power to terminate the VF.

Premature ventricular beat, ventricular tachycardia and VF were successfully induced in the first 4 groups. The minimum and maximum threshold of arrhythmia was observed in groups II (0.1 ± 0.07 mA) and III (1.2 ± 0.05 mA), respectively. The longest duration of arrhythmia induced by hypokalemia (240 ± 45 s), while the shortest one provoked by electrical stimulation (10 ± 4 s). The maximum dominant frequency of arrhythmia was observed in group III (14.9 ± 1.2 Hz), while the lowest dominant frequency was related to group I (7.1 ± 1.6). The mean number of ablation was 20 ± 3 and VF terminated in 10% of all arrhythmias.

Experimental arrhythmia can be induced in rat isolated heart by the all 4 protocols. However, increasing end diastolic pressure and hypokalemia are the most efficient methods for induction of ventricular arrhythmia. Left ventricular ablation by using DC voltage and AV node pack software is a useful method to terminate ventricular arrhythmias.

In this study, effects of digoxin on the cardiac electrophysiology and mechanical properties were examined in a rat model of heart failure induced by doxorubicin.

In order to induce heart failure, doxorubicin 5 mg/kg was injected to rat, i.p., once per week for 3 weeks. Heart failure was confirmed after 5 weeks, by measuring electrical, mechanical and histological changes in 12 isolated hearts. Isolated Langendorff perfused hearts were then treated with digoxin (0.1-80 µM) during a 60 min period and functional outcomes were assessed.

Effect of digoxin on the heart was biphasic. In concentrations below 80 µM (the first phase) digoxin significantly increased LVDP (left ventricular diastolic pressure) and RPP (heart rate × LVDP) .LVDP and RPP were also increased at the concentrations higher than 80 µM (the second phase). However, coronary flow, heart rate, left ventricular developed pressure and cardiac output were significantly decreased in the second phase.

Effects of digoxin on doxorubicin cardiomyopathy are biphasic. Electrical and functional changes in the second phase can be considered as an indicator of digoxin cardiotoxicity.

Intranodal pathways of atrioventricular (AV) node play a vital role in the delay of conduction time in response to various atrial inputs. The present study was aimed to determine the frequency-dependent electrophysiological properties of concealed slow pathway according to a functional model of isolated rabbit atrioventricular node preparation after fast pathway ablation. Experiments were carried out in rabbit isolated heart AV-nodal preparations (N=8) by superfused/perfused mode. Extracellular recording was carried out from transitional cells of posterior and anterior extension of AV-node and upper part of atrium and its bundle. Unipolar silver electrode (100 μm) and direct voltage (100-110 V) was applied to create AV-nodal fast pathway ablation. Minimum conduction time (AHmin) was significantly increased after fast pathway ablation (p<0.05). Fast pathway ablation had no significant impact on fatigue phenomenon but significantly reduced facilitation value (p<0.05). Rate-dependency properties of concealed slow pathway were explained according to functional nodal model. The mathematical functional model accurately simulated frequency-dependent electrophysiological properties of concealed slow pathway after fast pathway ablation, but some modifications are necessary for accurate prediction of nodal behavior in various cycle lengths and in arrhythmia. Concealed slow pathway may be considered as a potential electrophysiological substrate of fatigue and facilitation phenomenon

The aim of the present study was to determine direct effects of NO modulation on protective electrophysiological properties of atrioventricular node (AV node) in the experimental model of AF in rabbit. Isolated perfused rabbit AV nodal preparations were used in two groups. In the first group (N=7), LNAME (50μM) was applied. In the second group (N=12), different concentrations of L - argenine (250 μM - 5000 μM) were added to the solution. Programmed stimulation protocols were used to quantify AV nodal conduction time, refractoriness and zone of concealment. AF protocol was executed by software with coupling intervals (ranging from 75 – 125 msec). L-NAME had depressive effects on basic AV nodal properties. L-Arginine (250μM) had direct inhibitory effects on nodal conduction time, Wenckebach and refractoriness. Significant increases in the number of concealed beats were induced by L-Arginine (500 μM). Number of concealed beats were increased from 700.7 ± 33.7 to 763 ±21 msec (P<0.05). Trend of zone of concealment prolongation in a frequency-dependent model was abrogated by Larginine (250, 5000 μM). NO at low concentration (in the presence of L-NAME) had facilitatory role on AV nodal properties, but at high concentration (in the presence of L-arginine) enhanced protective role of AV node during AF. Biphasic modulatory role of NO may affect protective behavior of AV node during AF.

Considering the long traditional history of anti-inflammatory and anti-spasmodic effects of Matricria spices on the gastrointestinal system, the present study aimed to investigate the role of calcium channels and Histamine receptors in the inhibitory effects of hydroalcoholic dry extract of German chamomile (Matricaria recutita L.) on the isolated rabbit jejunum. All experiments were done on the isolated jejunum of New Zealand rabbits (1.8-2.5 kg). Dry extract of aerial parts of M. recutita was obtained by the maceration technique. The study was performed on two groups (n=6 in each group). In the first group, the effects of cumulative concentrations of M. recutita (3×10-3-1×10-2 mg/ml) on normal and K+-induced contractions (50 mM) of isolated jejunum were studied. In the second group, the inhibitory role of M. recutita (3 – 13×10-3 mg/ml) was evaluated in the presence and absence of histamine and cetrizine. In the presence and absence of 10 μM certizine, a histamine H1-antagonist, a concentration-dependent inhibitory effect of M. recutita extract in the range of 3-13×10-3 mg/ml was recorded the rabbit jejunum. Results showed that EC50 of M. recutita in the absence and presence of K+ was 6.3×10-3 and 6.5×10- 3mg/ml, respectively. IC50 values for two concentrations of M. recutita (8×10-3, 1×10-2) to abrogated contractive phase of Histamine was 9.55 × 10-6 and 1.57 × 10-6 μM. Cetrizine (10 μM) abolished inhibitory effects of M. recutita (IC50=3.6×10-3), (p< 0.001). Dry extract of matricaria recutita had inhibitory effects on the contractions of isolated rabbit jejunum. Calcium channels and histamine were involved in these antispasmodic effects

Developmental changes in atrioventricular nodal conduction time and refractoriness have been shown in several studies. Prevalence of atrioventricular nodal reentrant tachycardia (AVNRT) is clearly age-dependent. The purpose of this study was to determine developmental changes of basic and frequency-dependent electrophysiological properties of the atrioventricular node (AV-node) in neonatal and adult rabbits. In this study, the effects of increasing age on the basic and rate-dependent properties of isolated perfused AV-node were analyzed in neonatal (2-week-old) and adult (12-week-old) New Zealand rabbits. Specific stimulation protocols of recovery, facilitation and fatigue were separately applied in each group (n=7). Unipolar extracellular field potential was recorded by a silver electrode (100 M). The results showed that the basic nodal properties (ERP, FRP, WBCL and AHmax) were significantly shorter in neonates compared to the adult group. The magnitude of fatigue was also decreased in the neonatal group compared to control (18.9 ±3.3 vs. 11.1 ± 1.2 msec). Time constant of recovery of the adult group was significantly higher than the neonatal group (P<0.05). The results of this study showed that nodal basic and frequency-dependent properties are age-related and different developmental changes of slow and fast pathways are responsible for this behavior and may reveal the grater susceptibility of AVNRT in young adults compared to infants.

Recent studies have shown acute cardioprotective effects of cyclosporine. The aim of the present study was to determine the protective role of cyclosporine on the model simulated the rotational nodal arrhythmia (AVNRT) by using extracellular field potential recordings of isolated atrioventricular-node (AV-node) of rabbit. This study was performed on isolated double-perfused AV-node of male New Zealand rabbits (1.5-2.5 kg) in one group (n=7). Basic and rate-dependent stimulation protocols (recovery, facilitation, fatigue) and arrhythmia threshold (index of refractoriness) and % Gap incidence were measured for assessment of electrophysiological properties of the AV- node. All stimulation protocols were repeated in control step and in the presence of various cumulative concentrations of cyclosporine (0.5 - 10 μm). Cyclosporine prolonged the effective refractory period from 114.3±7.9 to 142±7.3 msec at the concentration of 10 μm. It also prolonged the functional refractory period from 162±3.3 to 178.6±5 msec and increased the time of Wenckebach at the concentrations of 5 - 10 μM. Various concentrations of cyclosporine increased fatigue and reached a significant level at 10 μm. Gap incidence was 82%, 16.6% and 20% in the control and treatments with 0.5 and 10 μm of cyclosporine, respectively. Block of MPTP by cyclosporine caused inhibition of basic and rate-dependent properties of atrioventricular node. Cyclosporine, by raising the threshold of arrhythmia, could be possibly considered as an anti- AVNRT drug.

Despite extensive studies about effects of Crataegus monogyna on cardiovascular diseases yet, a few study has been undertaken antiarrhythmic property of this plant. Aims of the present study were: 1) To determine the protective role of methanolic extract of C.monogyna on the rate-dependent model and the concealed conduction. 2) To explore the role of Na+-K+ A TPase in the protective role of C.monogyna. In all experiments were used of male New Zealand rabbits (1.5-2kg). Stimulation protocols were used to measure basic and rate-dependent (recovery, atrial fibrilation and zone of concealment) AV nodal properties in two groups(N=14). In the first group all the stimulation protocols before and after different concentrations of C.monogyna extract were repeated (n=7) in the second group (n=7) in the presence of all stimulation protocols Ouabaine(0.05 m M) and extract were repeated. All results have been shown as Mean±SE. Basic and rate-dependent properties of node were inhibited after addition of plant extract of C.monogyna to KerebsHenselite solution. At the maximum concentration of cratagus.m(30 mg/l),WBCL cycle longth is increased significantly from 156.5±3.4 to 173±5.8 ms and nodal functional refractory is prolonged from 164.4±4.1 to 182.7±3.8 ms(P < 0.05).Was recorded Significant decreases of ventricular rhythm in both selective concentrations of plant. The depressent electrophysiologic effect of C.monogyna on the AV node did abolish inhibt by ouabaine.(Selective inhibitore Na+-K+ A TPase Enzyme). All results are indicating the potential anti-arrhythmic and protective effects of C.monogyna. The effect of plant in increasing nodal refractory period and widen concealment zone might be the major mechanism of this plant. The protective role of cratagus.m does not related to the Na+-K+ A TPase activity.

Herbal remedies are suitable alternatives for synthetic drugs due to their availability, minimal side effects and lower price. Biologically active substances of plant origin represent an essential branch of modern cardiovascular pharmacotherapy. The aim of the present study is to investigate rate-dependent electrophysiological effects of Crocus sativus on extra-cellular field potential of isolated rabbit heart in-vitro. Male Newsland rabbits (.5- kg) were used in all of experiments; various experimental stimulating protocols (WBCL, Recovery, rate-dependent protocols) were applied to study electrophysiological properties of Node (N=5). All of the stimulated protocols repeated in the presence and absence different concentration of saffron (54,08 mg). Results were shown as mean ± SE. Saffron inhibited basic and rate-dependent electrophysiological properties of AV-Node. Significant prolongation of WBCL from 4±4.7 to 65.9±6.7 msec "in control and saffron group" was recorded (p<0.05). Rate-dependent protective role of plant to increases difference between atrial and nodal effective refractory period and was observed (from 0 ± 5.5 to 3.6 ± 7.4 msec in control and saffron) (p<0.05). Rate-dependent minor inhibitory role of Crocus sativus in AV-Node can modify protective role of AV-Node during arrhythmia.

Electrophysiological studies have demonstrated a relationship between aging and atrioventricular (AV) nodal conduction and refractoriness. The aim of the present study was to determine the effects of nodal aging on dynamic AV nodal field potential recording during atrial fibrillation (AF) in rabbit. Two groups of male New Zealand rabbits (neonatal 2-week-olds and adult 12-week-olds, n=14 each group) were used in this study. Field potential recordings were executed by silver electrodes with a diameter of 100 M. Pre-defined stimulation protocols of AF, zone of concealment (ZOC) and concealed conduction for determination of the electrophysiological properties of the AV-node were separately applied in each group. Results of the study showed that mean ventricular rate (HH) during atrial fibrillation was smaller in the neonatal compared to the adult group (229.1 ± 8.3 versus 198.6 ± 13.1 msec, respectively). Also ventricular distribution conduction pattern showed two peaks in the adult and one peak in the neonatal group. Analyzing the zone of concealment in different rates and after concealed beat indicated that the zone of concealment in neonates were significantly smaller compared with adult rabbits and increasing zone of concealment, which is accompanied with increasing ventricular rate is abrogated in the neonatal group (5 ± 3.3, 12.2 ± 6.3 msec). The results of this study showed that the electrophysiological protective dynamic behavior of the AV node during atrial fibrillation is smaller in neonates compared to adults. Narrower zone of concealment, abrogation rate dependent trend of the zone of concealment and shorter nodal refractoriness can account for the specific nodal electrophysiological properties of neonatal rabbits.

Recent evidence has indicated that statins can reduce the incidence of both supraventricular and ventricular arrhythmias with various mechanisms. The primary goal of the present study was to determine direct protective role of simvastatin in modifying concealed conduction and the zone of concealment in a simulated model of atrial fibrillation (AF) in an isolated atrioventricular (AV) node in rabbits. Male Newsland rabbits (1.5-2 kg) were used in all experiments. Stimulating protocols (recovery, AF, zone of concealment) were used to study electrophysiological properties of the node in one group (N=8). All of the stimulated protocols were repeated in the presence and absence of different doses of simvastatin (0.5-10 μm). Results were shown as mean ± S.E. Significant inhibition of the basic properties of the AV node was observed after the addition of simvastatin. Significant prolongation of Wenkebakh index (wbcl) from 138.7±5.6 to 182.1±6.9 and functional refractory period (FRP) from 157.7±5.9 to 182.1±6 msec at the concentration of 10 μM was observed. Maximum efficacy of simvastatin in atrial fibrillation (AF) protocol was observed at the concentration of 3.10 μM, that was accompanied with prolonged HH interval and increased number of concealed beats. Zone of concealment significantly increased at the concentrations of 1.3 and 10 μM. This study shows the protective effect of simvastatin in the prolongation of ventricular beats during atrial fibrillation. The effect of simvastatin in increasing AV-nodal refractory period and zone of concealment are probably the anti-arrhythmic mechanisms of this drug.

Recent studies showed that nitrergic system have specific modulatory effects on electrophysiological properties of atrioventricular (AV) node. The aim of this study was to determine the effects of nitric oxide (NO) on the electrophysiological properties of isolated rabbit AV node and to investigate the role of adrenergic and cholinergic receptors in the mechanism of its action. In our laboratory, an experimental model of isolated double-perfused AV-node of rabbits weighing 1.5-2 kg was used. Specific experimental protocols of recovery, Facilitation, Fatigue and Wenckbach were applied in both control and in the presence of the drug. A total number of 35 rabbits were divided randomly into the following groups (n=7): 1) L-Arg (NO donor) (250, 750 and 1000 μmol), 2) L- NAME, a NO synthesis inhibitor (25, 50 and 100 μmol), 3) L-Arg + L- NAME, 4) Nadolol (1 μmol), 5) Atropine (3 μmol). All data were shown as mean ± SE. The level of statistical significance was set at p<0.05. Our results revealed the depressant effect of L-Arg on the basic and rate-dependent electrophysiological properties of AV-node. L- NAME did not deteriorate the effects of L-Arg on the basic and rate-dependent properties, nevertheless, at high concentration (100 μmol) it had a direct inhibitory effect on the AV-node. Nadolol and atropine could prevent the effects of NO on the basic nodal characteristics and the fatigue phenomenon, respectively. Nitergic system can affect basic and rate-dependent electrophysiological properties of the AV-node through adrenergic and cholinergic receptors.

The aim of this study is to obtain new insight into possible relation between functional properties of slow concealed pathway and rate-dependent properties of AV-node. Rate-dependent nodal properties of recovery, facilitation, and fatigue were characterized by stimulation protocols in one groups of (N=7) isolated superfused AV-Nodal rabbits. Small miniature lesions were made by delivering constant voltage (110 V-100 s) with unipolar silver electrode. Fast pathway ablation significantly decreased facilitation and had no effect on fatigue and nodal refractoriness. The most important effect of fast pathway ablation was prolongation of minimum conduction time. The FP-ablation revealed the presence of the concealed SP. Rate-dependent property of node is dependent to dynamic interaction between concealed slow with slow pathway. Fast pathway involved in the mechanism of facilitation.

Dual pathways have a determinant role in the occurrence of atrio nodal tachyarrhythmia (AVNRT). The aim of present study is to determine the role of slow pathway (SP) in the concealment zone and protective role of AV node during atrial fibrillation (AF). In 7 isolated nodal rabbit preparation zone of concealment and concealed conduction is quantified by Specific pacing protocols. The differences between effective refractory period of atrial and AV node in the basic cycle length and after introducing concealed beat was considered as Zone of concealment. AَF was simulated by high-rate atrial pacing with random coupling intervals. Small miniature lesions were made in superior compact node by delivering constant voltage100-110 v. FP ablation resulted in longer minimum nodal conduction time, but without change of nodal effective and functional refractory period. Zone of concealment was determined as 10±4. 8 ms. After fast pathway modification nodal characteristics during AF did not change significantly (average H–H intervals, number of concealed beats and zone of concealment). Fast pathway has not a determinant role in the mechanism of concealed conduction and zone of concealment. During AF, the wave fronts did not used fast pathway to conduct to ventricles.

The ablation technique is one of the important therapeutic interventions for treatment of AV Nodal tachyarrhythmia. Different animal models have been developed to study the effects of ablation on the functional interanodal structure. The aim of the present study was to develop a new model of computer analysis to produce lesions by using direct voltage in isolated perfused rabbit AV-Node. The model of Superfused-perfused isolated AV-Node of rabbit was used in our study. Posterior nodal extension (slow pathway) and anterior nodal approaches (fast pathway) were ablated by using direct voltage (100-110 V) in 30 sec. All stimulation protocols and computer analysis were performed by the custom made software that has been developed in the Electrophysiology laboratory of Golestan Cardiovascular Research Center. All protocols were applied to 2 groups (5 rabbits in each group). His deflection was detected by software (AV-Node pack) and nodal recovery curved was constructed on line. By using specific electrophysiological criteria, we could precisely predict the place of nodal ablation. Slow pathway ablation caused significant ERP and AHmax prolongation and fast pathway ablation caused significant AHmin prolongation. Histology examination confirmed the ablation results. Computer analysis of nodal ablation is a new method to induce specific lesions in AV-nodal pathways. Changing dynamic electrophysiological behavior of AV-node after ablation is an important index for predication of outcome of ablations.

Background and Preliminary studies have been established to examine the cardiotonic effect of Citrus bigaradia extract, by implenenting various mechanisms. The functional protective role of this plant against supraventricular tachyarrhythmia remains to be determined.The present study is designed to assess the role of hydroalcoholic extract of Citrus bigaradia by modifing the electrophysiological properties of atrioventricular node, during simulated experimental atrial fibrillation in rabbits and also, to determine the role of adrenoceptores regarding effects of Citrus bigaradia on the AV node. In this present study, Newsland male rabbits(1.5-2 kg) was used. Programmed stimulation protocols (Recovery, Wenckbach, Atrial fibrilation and Zone of concealment) were applied in two groups (N=23) to assess electrophysiological properties of isolated rabbit AV node. In the first group (N=10), different concentrations of hydroalcoholic extract of Citrus bigaradia were added to thyrods to detect nodal concealed conduction. In the second group (N=13), the effects of extracts (54-108 mg/L) were analysied in the presence of β-adereceptor blocker(Nadolol 2 µm). AF protocol was simulated by high-rate atrial pacing with random coupling intervals (range 75-125 ms). All data have been shown as Mean±SE. Citrus bigaradia, had biphasic concentration-effect pattern, such as in low and intermediate concentrations (0.8-3.2 mg/L), shortened nodal functional refractory period and Wenckebach. We observed a non-significant decrease in the average H-H intervals and numbers of concealed beats in all concentrations of Citrus bigaradia. Zone of concealment was shortened by this plant. Nadolol (2 µm) prevented the whole effects of Citrus bigaradia on the nodal conduction time, refractoriness and concealed conduction. The above results indicate the potential pro-arrhythmic effects of Citrus bigaradia in worsing supraventricular tachyarrhythmia. The effects of plant to decrease the AV-nodal refractory period and concealment zone may be considered the major mechanism of this plant.At least some parts of effects of Citrus is mediated through β-adrenoceptores.

To determine average consultation time and evaluate its determinants in general practitce in Gorgan, Iran. 620 consultations from 62 general practitioners were evaluated. In addition physician consultation time was measured with a stopwatch. After the consultation, a questionnaire was completed for all patients. Data was analyzed by SPSSv11.5 software. The average consultation time of general practitioners in Gorgan was 6.9±2.6 minutes. Consultation time was directly correlated with patient’s interruption, educational level of patient and prescribing volume of physician. This study showed that consultation time in Gorgan is lower than many developed and developing countries. High number of patients in waiting rooms and high prescription volume might explain shorter consultation time in Gorgan.

Background and Previous studies have demonstrated the cardiovascular effects of Urtica dioica (Nettle) such as anti-hypertensive, and negative inotropic effects on heart. The effects of plant on atrioventricular node has not been explored yet.Inhibitory Na+-K+-ATPas pump has been shown ny U. dioica. The aims of the present study were: 1) to determine concentration-dependent effects of ethanolic extract of nettle on the nodal basic and functional properties. 2) to campare mechanism of action nettel with ouabaine and verapamil. This was an experimental study. Male New Zealand rabbits (1-1.3 kg) were used in all of the experiments Various experimental stimulating protocols (Wbcl Recovery, Facilitation, Fatigue) were applied to assess electrophysiological properties of Node. We used isolated perfused AV-nodal preparation (n=18). All protocols were repeated in the presence and absence (control) of different concentration (0.2-0.4 g/l) of Nettle, verapamil (0.1μM) and ouabaine (0.25μM). Results were shown as Mean ± SE and a probability of 5% was used to indicate statistical significance. In the presence of Nettel, significant increases in WBCL (150.7± 4.3 to 180 ±15.2msec), AVCT (44±2.5 to 54±1.7msec), ERP (125±13 to 149 ±20.6msec) and magnitude of fatigue (ΔAH) 6 ± 0.9 msec were observed. The nettel has less inhibitory activity than verapamil, such as ERP of Nettel was 40% of verapamil. Also, Nettel had similar electrophysiological effects in regard to ouabain. In the present study, negative dormotropic effect of extract, Citrus bigaradia of Nettel, was observed on the isolated AV-nodal preparation. The same electrophsiological trend of ouabain and Nettel, may indicate the role of Na+-K+-ATPas pump in the deppresant effect of Nettel.

Drug interactions are among the most important medication errors and often can potentially cause adverse drug reactions that may affect treatment course. In the present study we evaluated the effects of face to face education on reduction of drug interactions on insured prescription of physicians. We selected the physician’s prescriptions and identified drug interactions of physician’s prescriptions. The prepared questionnaire was introduced to physicians through face to face education, feed back of information and designation of pamphlets. Having educated the physicians, their prescriptions were reevaluated. The incidence of drug interaction was %8.49, however, mean number of drug interaction was significantly reduced after education (p<0.001). Meanwhile, a significant increment was observed in physicians’ knowledge towards possible mechanism, pharmacologic classification and drug interactions (p<0.001). Our results revealed the importance of active education in reducing the percentage of drug interactions and the effects of education in increased physician’s knowledge towards drug interactions.