Search published articles


Showing 58 results for Subject: Cardivascular system

Mohammad Kazem Gharib Naseri, Akbar Heidari,
Volume 10, Issue 1 (4-2006)
Abstract

Introduction: Our previous studies showed that hydroalcoholic extract of leaf of Vitis vinifera relaxes the phenylephrine-induced contraction in rat thoracic aorta. This effect was dependent on endothelial integrity and NO-cGMP system. The vasorelaxant effect of extract was much lesser on KCl-induced contraction. We, therefore, postulated that K+ channels are involved. The main aim of the present study was to determine the type of K+ channels involved in this vasorelaxant effect. Methods: Thoracic aorta with intact endothelium was removed from adult male Wistar rats (170-220g). The aorta was mounted in an organ bath containing Krebs-Henseleit (37 ºC, pH 7.4) bubbled with O2. Aortic contractions were recorded isometrically under 1 g resting tension. The aorta endothelium was considered intact if acetylcholine (1 μM) could induce more than 70% aorta relaxation on 1μM phenylephrine-induced contraction. Extract was prepared by maceration method using 70% alcohol and the solvent was then evaporated. Results: The results showed that in the presence of tetraethylammonium (10 mM), the vasorelaxant effect of extract (0.25, 0.5, 1 and 2 mg/ml) was reduced (P<0.001, n=7). In contrast, glibenclamide (1 μM) had no effect. In calcium-free (plus 0.1 mM of EDTA) Krebs-Henseleit solution, the vasorelaxant effect of extract (0.25, 0.5 and 1 mg/ml) was reduced (P<0.0001, n=8). Furthermore, the vasorelaxant effect of extract was unaffected by indomethacin (1 μM). Conclusion: These results suggest that Vitis vinifera leaf hydroalcoholic extract induces relaxation in rat aorta possibly by opening the Ca2+ -operated K+ channels but, not ATP- sensitive K+ channels and extracellular calcium was essential for inducing vasorelaxation by extract. Furthermore, cyclooxigenase was not involved in this vasorelaxant effect.
Hamdollah Panahpour, Ali Akbar Nekooeian, Gholam Abbas Dehghani,
Volume 11, Issue 2 (8-2007)
Abstract

Introduction: Development of brain edema following focal cerebral ischemia exacerbates primary ischemic injury. Blood brain barrier (BBB) opening is an important part of edema named as vasogenic brain edema. In this study, quantitative alterations of BBB permeability is experimentally evaluated using transient focal cerebral ischemia in the rat. Methods: Two groups of male rats (ischemic and sham) were anesthetized with chloral hydrate. In the ischemic group, middle cerebral artery (MCA) was occluded for 60 minutes using intraluminal filament method followed by reperfusion, whereas, in the sham group the same procedure, except MCA occlusion, was used. An IV injection of Evans blue (EB) was done 30 minutes after surgery. After 24 hours of reperfusion the neurological deficit score (NDS) was evaluated with a standard test. Then the animal was killed, the brain excised and prepared for quantitative evaluation of BBB permeability by detection of Evans blue (EB) extravasation. Results: The mean of NDS in sham and ischemic groups were 1 and 2.25±0.31 respectively, indicating severe motor disabilities due to cerebral ischemia. In the ischemic group the concentration of EB in the right hemisphere (ischemic) was 12.48±1.94µg/g which was significantly higher than of the left hemisphere (non ischemic 1.44±0.39µg/g) or both hemispheres of the sham group. Furthermore, a direct correlation seems to exist between NDS and EB concentration in both groups. Conclusion: This study is indicating that quantitative detection of Evans blue extravasation technique is capable of measuring the alterations of BBB permeability in cerebral ischemia in the rat.
Mohsen Alipour, Davood Sohrabi, Feridoun Hydarpour, Ramazan Falah, Mustafa Mohammadi,
Volume 11, Issue 3 (12-2007)
Abstract

Few studies have investigated the effect of exercise on homocysteine and 15-F21-isoprostane in animal models. The present study was designed to examine the effect of long-term exercise and/ or high cholesterol diet on MDA, 15-F21-isoprostane and total homocysteine in the aorta and plasma of rabbits. Methods: 56 male rabbits were divided into four groups: normal diet (control), normal diet with exercise, high-cholesterol diet without exercise and high cholesterol diet with exercise. Animals of exercise groups ran on a treadmill at 0.88 km/h for 7.5 –90 min/day (5 days/week) for 12 weeks. At the end of exercise protocol, blood samples were collected and tHcy, 15-F21-isoprostane were measured using enzyme immunoassay (EIA) kits. MDA levels were determined by the thiobarbituric acid assay. Thoracic aorta was isolated to evaluate atherosclerosis as well as tHcy, 15-F21-isoprostane and MDA levels. Results: Exercise reduced atherogenic diet-induced atherosclerotic lesions in aorta along with positive changes in plasma cholesterol profile. Atherogenic diet significantly increased plasma and aorta concentrations of MDA and tHcy. Exercise significantly reduced diet-increased plasma and aorta concentrations of 15-F21-isoprostane and tHcy in normal animals. MDA levels did not show significant change due to exercise and/or high cholesterol diet feeding. There was a positive correlation among plasma cholesterol, homocysteine and 15-F21-isoprostane in exercised groups compared with control. Conclusion: Our results suggest that elevated homocysteine level can be considered as one of the multiple risk factors in the development of atherosclerosis. In addition, exercise may effectively reduce plasma and aorta homocysteine and 15-F21-isoprostane and may be effective in prevention and attenuation of atherosclerosis.
Mohammad Reza Bigdeli, Sohrab Hajizadeh, Mehdi Frouzandeh, Ali Khoshbaten,
Volume 11, Issue 3 (12-2007)
Abstract

Introduction: Prolonged and intermittent oxygen pre-exposure is associated with protection against ischemic reperfusion (IR) injury. In the current study, attempts were made to investigate the relationship between exposure to prolonged and intermittent normobaric hyperoxia (NBHO) and expression of excitatory amino acids transporters (EAATs) and TNF-α level. Method: Rats were divided into four main experimental groups, each of 21 animals. The first two were exposed to 95% inspired NBHO 4 h/day for 6 consecutive days (intermittent NBHO) or for 24 continuous hours (prolonged NBHO). The second two groups considered as controls and were exposed to 21% oxygen in the same chamber (normobaric normoxia, NBNO). Each main group was subdivided to MCAO (middle cerebral artery occlusion), sham-operated (without MCAO) and intact (without any surgery) subgroups. After 24h, MCAO subgroups were subjected to 60 min of right MCAO. After 24 h reperfusion, neurologic deficit scores (NDS) were assessed in MCAO-operated subgroups. Immediately and 48 h after pretreatment, blood sampling were done for assessing level of serum TNF-α. The effect of intermittent and prolonged NBHO on EAATs expression level was also measured using western blotting. Result: Preconditioning with prolonged and intermittent NBHO decreased NDS and up-regulated EAAT1, EAAT2, and EAAT3, significantly. Also, oxygen exposure of prolonged and intermittent NBHO increased the level of serum TNF-α. Conclusion: Although further studies are needed to clarify the protective mechanisms OF hyperoxia, the intermittent and prolonged NBHO seems to partly exert their effects via increasing the serum level of TNF-α and upregulation of glutamate transporters. However, the intermittent NBHO seems to have appropriate effects with low toxicity.
Moslem Najafi, Afshin Gharakhani, Hamed Ghavemi, Tahereh Eteraf Oskouei,
Volume 11, Issue 3 (12-2007)
Abstract

Introduction: In the current study, protective effect of natural honey applied during ischemia/reperfusion (I/R) was studied on infarct size in ischemic heartheart. Methods: Ischemic hearthearts (n=8 per group) were mounted on a Langendorff apparatus at constant pressure then subjected to 30 min regional ischemia followed by 120 min reperfusion. In control group, the hearts were perfused by a modified Krebs-Henseleit solution throughout the experiment, however, in the test groups they were perfused by Krebs solution enriched by natural honey (0.125, 0.25, 0.5 and 1%). At the end of reperfusion, the infarct size was determined by triphenyltetrazolium chloride and computerized planimetry methods. Results: The results showed that perfusion of ischemic hearthearts with natural honey produces significant reduction in infarct size and volume of infracted tissue. In the control group, infarct size was 45.6±3.4%, while honey (0.125, 0.25, 0.5 and 1%) reduced it to 14.8±5.1 (p<0.001), 24.6±7.3 (p<0.01), 31.4±7.3 (p<0.05) and 42.6±6.1% (p>0.05), respectively. In addition, infracted volume was lowered from 229±22mm3 (control) to 78±26 (p<0.001), 120±30 (p<0.01), 160±31 (p<0.05) and 201±45mm3 (p>0.05), respectively. Conclusion: The results of this study showed protective effects of natural honey against I/R injuries as reduction of infarct size. Probably, antioxidant activity of honey, scavenging of free radicals and presence of energy sources such as glucose are involved in its cardioprotective effect. Lower honey concentration seems to be more effective.
Zahra Barabadi, Sohrab Hajizadeh, Mohammad Javan, Batool Erfani, Ali Heidarian Pour,
Volume 11, Issue 4 (1-2008)
Abstract

Introduction: Endothelium and smooth muscle dysfunction are the most important complications of diabetes. In type 1 diabetic patients, absence of insulin leads to vasoconstriction and lower skin blood perfusion. Release of some mediators by endothelium which is induced by insulin causes vasodilation, but the exact mechanism of insulin vasodilatory effect is not detected properly. At present study we investigated the role of NO as a vasodilator and KATP channels and their intraction in the vasodilatory effect of insulin on the skin vessles. Methods: Male wistar rats (200-250 gr) were made diabetic by streptozocin (50mg/kg, s.c). After 40 days of diabetes induction, skin blood flow was measured by Laser Doppler Flowmetry technique (LDF). Insulin, LNNA (NO blocker) and Glibenclamide (KATP blocker) infusion were made by infusion pump subcutaneousely. Results: 1- Insulin increases skin blood flow in both control and diabetic groups and this increase was significantly higher in diabetic group. 2- Insulin vasodilatory effect was decreased by LNNA. 3- The vasodilatory effect of insulin was decreased by Glibenclamide. 4- Simultaneous block of both NO and KATP was more effective. Conclusion: Insulin induces vasodilation in part by NO release and partly by activation of K ATP channels. However some interaction has been seen between both routes. Although by block of both these routes, blood flow has not been completely inhibited. So it is supposed that other factors may be involved in this effect and yet to be illucidated.
Iran Pouraboli, Sohrab Hajizadeh, Hamid Najafipour, Ali Khoshbaten, Mohammadjavad Rasaei,
Volume 12, Issue 1 (5-2008)
Abstract

Abstract Introduction: In this study the role of PGE2 as an important inflammatory mediator in Indomethacine and Theophylline effects on joint diameter and vascular response of chronically inflamed rat knee joint to saphenous nerve stimulation was investigated. Methods: Inflammation was induced by intraarticular injection of 0.2 ml Freund,s Complete Adjuvant (FCA) and 3, 7, 14, 21 days post injection knee joint diameter, blood flow changes to saphenous nerve stimulation and PGE2 content of joint were assessed using micrometer, laser Doppler flowmeter and enzyme immunoassay kit respectively. In another three groups, control and inflamed receiving Indomethacin or Theophylline also these variables determined. Results: After inflammation induction in rat knee joint constrictory response of joint vessels to saphenous nerve stimulation reduced but joint diameter enhanced significantly. Furthermore in inflamed rats received Theophylline both vascular response of knee joint to nerve stimulation and joint diameter decreased however, daily reception of Indomethacine had no effect on joint edema but increased constrictory response of joint vessels to nerve stimulation. Furthermore PGE2 content increased in inflamed knee joint in comparison with control (uninflamed) during two weeks but in rats receiving Indomethacine it reduced significantly on days 3, 14. Also in inflamed rats treated by Theophylline PGE2 content was significantly decreased only in day 14. Conclusion: In chronic inflammation PGE2 as an inflammatory mediator play an important role in edema and modulation of constrictory response of joint vessels to nerve stimulation. Furthermore antiedematotic effect of Theophylline also may be mediated by PGE2 through decrement of vascular permeability.
Rafati Rafati, Manijhe Mokhtari-Dizaji, Hajir Saberi, Hosein Chegini,
Volume 12, Issue 1 (5-2008)
Abstract

Instruction: Measurement of brachial artery diameter variation by ultrasound methods has commonly been used to test the endothelial function. It is known that the artery diameter is increased by flow stimulation. Therefore in the present study, the effect of external obstruction, as flow stimulation, on the radial strain of the brachial artery was assessed. Also the biomechanical behavior of the artery due to the changes in obstruction cuff position was evaluated. Methods: Firstly, for evaluating the effect of flow stimulation on healthy men's brachial artery, 200 mmHg pressure and 5 minutes of obstruction was applied. Then, without flow stimulation, it was evaluated by ultrasonic method. In order to evaluate the optimum cuff position with maximum biomechanical variation of the brachial artery, arteries of two regions including the proximal brachial (upper arm) and middle forearm of 10 healthy men were obstructed by 200 mmHg of stress. By acquiring artery diameter variation and estimation of radial strain, multiple frames of the B-mode ultrasonic images were saved on personal computer and maximum artery diameter in the systolic phase, artery diameter in the end of the diastolic phase and the shape of offline were measured. According to relative diameter variations, radial strain percentages were estimated. The effects of external obstruction and the position of this obstruction on the radial strain of the brachial artery were analyzed by t-test. Results: In the first stage, the results of ultrasonic evaluation of the left brachial artery showed that the radial strain induced by stress (200 mmHg) was significantly increased 3.5 times compared to the normal condition without stress. Evaluation of the obstruction's location and its effect on the relative brachial artery diameter showed that with the application of 200 mmHg obstruction in 1/3 of the superior arm and the middle forearm, the radial strain of the artery were 10.44 ± 2.63 % and 4.97 ± 3.61 %, respectively. The statistical analysis of the brachial artery radial strain showed a significant difference between the two obstruction's locations and 33% increase of the obstructed brachial artery's diameter variation in 1/3 of the superior arm. Conclusion: The brachial artery's radial strain is increased by the external obstruction of the artery. This increase seems to be larger in the upper arm region of the artery compared to the middle forearm region.
Marzeieh Hoseini, Sohrab Hajizadeh, Yaghoub Fathollahi, Mojtaba Golmohammadi, Batoul Erfani, Ali Heidarian Pour,
Volume 12, Issue 1 (5-2008)
Abstract

Introduction:Adenosine as a potent vasodilator has physiological role in regulation of regional cerebral blood flow (rCBF). Metod: Laser-Dِoppler flowmetry technique was used to study pial vessels blood flow responses to adenosine receptors agonists and antagonist. Male Sprague Dawley rats (250-350g) that were housed in standard conditions, were anesthetized with Urethane (1.5g/kg). Adenosine (general agonist), NECA (A2Aand A2B receptor agonist) and CGS-21380(A2Aselective agonist), were used in absence and presence of A2A receptors- selective antagonist, ZM-243185, in naive and morphine-dependent rats. Results: Adenosine, NECA and CGS-21680 increased pial vessels blood flow in naive and dependent rats dose dependently. These responses were blocked significantly by ZM-243185. Responses of pial vessels to adenosine (10-4, 10-5, 10-6 M) and NECA (10-4, 10-5, 10-6 M) were increased significantly in morphine- dependent rats in comparison to naive rats. Pial vessels responses to CGS-21680 had not shown any significant deferences between morphine- dependent and naive rats. Conclusion:Based on these results it could be concluded that the role of A2B receptors in regulation of rCBF in morphine-dependent rats is more effective than A2A receptors.
Khalil Pourkhalili, Sohrab Hajizadeh, Ali Khoshbaten, Taki Tiraihi,
Volume 12, Issue 2 (8-2008)
Abstract

Abstract Introduction: Resent studies have been shown beneficial effects of hyperoxia pretreatment against ischemia-reperfusion injury in different organs. The aim of the present study was to investigate early and late effects of normobaric hyperoxia (≥95% O2) pretreatment on ischemia-reperfusion injuries in isolated rat hearts. Methods: Following 60 and 180 minutes of hyperoxia, rat hearts were isolated immediately (H60 and H180) or 24 hours later (H60/24 and H180/24), and subjected to 30 minutes of regional ischemia followed by 120 minutes of reperfusion. Incidence and severity of ventricular arrhythmias, mechanical function of the heart and coronary flow were assessed during 120 min of reperfusion. LDH and CK release and infarct size were also assessed. Results: Incidence and severity of reperfusion arrhythmias significantly reduced by hyperoxia pretreatment, especially in the early phase of treanment. H180 reduced the incidence of ventricular fibrillation (VF) to 0% vs. 50% of normoxic control, p<0.05). VF duration decreased in H180 group (0 vs. 50±31s in the NC group, p<0.05) and duration of VT decreased in H60 and H180 groups compared to normoxic control group (NC) (1.5±0.7 s and 7.5±2.5 s vs. 17.7±3.3 s respectively, p<0.05). Hyperoxia improves mycardial contractile function and improves coronary flow during reperfusion. Infarct size and enzymes release were also significantly decreased in early and late phase of hyperoxia pretreatment. Conclusions: These results indicate that hyperoxia pretreatment before induction of regional heart ischemia reduces cardiac infarct size and attenuates reperfusion induced arrhythmias in isolated rat heart. Keywords: Hyperoxia, Ischemia-reperfusion injury, Heart protection, Arrhythmias
Sohrab Hajizadeh, Batool Erfani, S. Mohammad Faghihi, Zahra Barabadi, Marzeieh Hosseini,
Volume 12, Issue 3 (11-2008)
Abstract

Beta-2 adrenoceptors in blood vessels are one of the active factors that play a role in regulation of tissue blood flow. in diabetic angiopathy, responsiveness of these receptors is decreased, while that is increased in inflammation. According to these opposite effects, the aim of this study was to investigate the vasodilatory response of knee joint blood vessels to salbutamol (Beta-2 adrenoceptor agonist) in IDDM with combination of acute inflammation. Acute knee joint inflammation was induced by intraarticular injection of kaolin 4% and induction of diabetes was performed by streptozotocine (55 mg/kg). Wistar rats weighting 200-300 gr were used. The animals divided in 5 groups as: the control, saline, diabetic, inflammatory and diabetic- inflammatory. Blood flow of knee joint was measured using Laser Doppler Flowmeter Technique (LDF). Vasodilatation of articular micro vascular was measured in response to topical application of different concentration (10 -11 -10 -1) of salbutamol. Results obtained in this study showed that: 1- Increased knee joint diameter and perimeter due to acute inflammation in diabetic rat knee joint were significantly lesser than that of inflammatory rats. 2- Responsiveness of Beta-2 adrenoceptors were increased in kaolin- induced acute inflammation. 3- In diabetic rats, kaolin- induced acute inflammation could not increase the responsiveness of Beta-2 adrenoceptors. Based on above mentioned results, we conclude that diabetes inhibits the increasing effects of acute inflammation on responsiveness of Beta-2 adrenoceptors.
Vahid Khori, Mohsen Nayebpour, Jafar Golalipour, Smp Firouzabadi,
Volume 12, Issue 4 (1-2009)
Abstract

Introduction: 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. Methods: 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). Results: 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. Conclusion: 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.
Asghar Ghasemi, Leila Siadmoradi, Amir Abbas Momenan, Saleh Zahedi Asl,
Volume 12, Issue 4 (1-2009)
Abstract

Introduction: Cigarette smoking affects nitric oxide production. The aim of this study was to determine associations between tobacco smoke and serum nitric oxide metabolites (NOx) concentration. Methods: Serum NOx concentration was measured by the Griess method in 230 nonsmokers, 238 active, 196 passive and 29 waterpipe smokers. Subjects were selected from participants of Tehran Lipid and Glucose Study and blood samples were taken 12-14 h after overnight fasting. Mean NOx values were compared between groups by analysis of variance and p values less than 0.05 were considered significant. Results: Serum NOx concentration was significantly higher in smokers (28.2±1.0 μmol/l) compared to passive (25.8±1.0 μmol/l) and nonsmokers (25.3±1.0 μmol/l) (p<0.05), while no significant difference was found in the level of NOx between passive and waterpipe smokers (29.0 ±1.1 μmol/l) compared to nonsmokers. Conclusion: Serum NOx concentration is increased in active smokers, which may be involved in the development of vascular diseases.
Vahid Khori, Mohsen Nayebpour, Abbas Mirabbasi, Mona Pourabouk,
Volume 13, Issue 1 (4-2009)
Abstract

  Introduction : 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.

  Methods : 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.

  Results : 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.

  Conclusion : 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.

 


Mojtaba Golmohammadi, Sohrab Hajizadeh, Mohammad Faghihi, Marzeieh Hosein, Kambiz Rohampour,
Volume 13, Issue 2 (8-2009)
Abstract

Introduction: In recent study both endothelium-dependent and endothelium-independent mechanisms have been reported for the action of β-adrenoceptor. The aim of this study was to investigate on the role of nitric oxide (NO) and cyclic guanosin monophosphate (cGMP) in vasodilation mechanisms of β2-adrenoceptors (β2-AR) in rat skin vessels. Methods: All drugs were injected subcutaneous into planar skin of hind paw. Injection volume was 10µl (5µl/min). Induction of anesthesia was perform with urethane 1.5 g/kg. Laser Doppler Flowmetery (LDF) technique was used for skin blood flow (SBF) monitoring. Results: The results obtained in this study showed that different doses of salbutamol, selective β2-AR agonist (1µM) caused a significant increase of SBF, but there was not any significant different in the response of different doses. Atenolol, selective β1-adrenoceptor antagonist (10µM) alone and with salbutamol had no significant effect on SBF. Propranolol, non selective β-adrenoceptor antagonist (1µM) by itself did not changed SBF, but significantly reduced the vasodilatory effect of salbutamol. LNNA, NO inhibitor (10µM) and methylen blue, cGMP inhibitor (3µM) caused a significant decrease of SBF 6/95% and 7/91% respectively. Salbutamol injection after LNNA and NO raised the SBF to 24/7% and 22.5% respectively, which shows a significant reduction in comparison to salbutamol’s effect (42.73%). Conclusion: The results indicated that, salbutamol dilate rat skin vessels via β2- ARs. NO and cGMP involved in β2-ARs mediated vasodilation and contribute to regulation of vascular skin tone. To elucidate the exact mechanism of this response more studies are needed.
Aref Salehi, Vahid Khori, Mohsen Nayebpour, Elnaz Rakhshan,
Volume 13, Issue 2 (8-2009)
Abstract

Objectives: 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). Material &Methods: 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. Results: 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). Conclusion: 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.
Farzaneh Ketabchi, Seyed Mostafa Shid Moosavi, Norbert Weissmann, Gholam Abas Dehghani,
Volume 13, Issue 2 (8-2009)
Abstract

Introduction: Acute respiratory disorders such as obstructive pulmonary diseases and hypoventilation may lead to alveolar hypoxia and hypercapnia which their effects on pulmonary vascular beds are controversial. The aim of this study was to establish the isolated perfused lung setup and investigate the effects of alveolar hypoxia and hypercapnia on pulmonary vascular resistance. Methods: White New Zealand rabbits anaesthetized and anticoagulated with heparin and trachea cannulated. Then the lung exposed and perfused with Krebs solution through pulmonary artery cannula. The ventilated-perfused lung was carefully excised from the chest and the healthy lungs were randomly divided into three groups (n=7 for each). Ventilation performed for 30 min with normoxic-normocapnic , or hypoxic-normocapnic, or hypoxic-hypercapnic gas mixtures. The percent changes of pulmonary vascular resistance per min (%PVR) and their maximum values were evaluated. Results: Hypoxic-normocapnic ventilation resulted in an initial sharp rise in PVR that after 8 min of exposure reversed to a slow decline. After 12 min of exposure a second steady rise in PVR occurred and continued until the end of the experiment. The rate of rise of PVR during hypoxic-hypercapnia was steeper (17.3±2.4% /min) compared to hypoxic-normocapnia (8.86±1.6% /min), but the maximum increases observed in PVR were similar in both conditions. Conclusion: In the isolated ventilated perfused lung, acute alveolar hypoxia had a complex influence on PVR and combination of hypoxia with hypercapnia transiently strengthened PVR without affecting its maximum level.
Mehravar Rafati, Manijhe Mokhtari-Dizaji, Hajir Saberi, Hadi Grailu,
Volume 13, Issue 3 (11-2009)
Abstract

Introduction: This study presents a computerized analyzing method for detection of instantaneous changes of far and near walls of the common carotid artery in sequential ultrasound images by applying the maximum gradient algorithm. Maximum gradient was modified and some characteristics were added from the dynamic programming algorithm for our applications. Methods: The algorithm was evaluated on the common carotid artery of 10 healthy volunteers. Local measurements of vessel intensity, intensity gradient and boundary continuity are extracted for all of the sequential ultrasonic frames throughout three cycles. We extracted the instantaneous changes of far and near arterial walls and hence the lumen diameter. The manual measurements were applied and compared for validation of the automatic method. Peak systolic, end diastolic and mean diameters extracted by the automated method were compared with the same parameters measured by the manual method throughout three cycles. Results: There was no significant difference between automated and manual methods (p>0.05) with paired t-test analysis. In the verification study, correlation between automated and manual methods was excellent (R2 = 0.85, p<0.05) with a negligible bias (0.003 mm) as determined by Bland Altman analysis. Conclusion: It is concluded that computerized analyzing method can automatically detect the instantaneous changes of the arterial walls in sequential B-mode images.
Fatemeh Mohagheghi, Mohammad Reza Bigdeli, Bahram Rasoulian, Ali Asghar Zeinanloo,
Volume 13, Issue 4 (1-2010)
Abstract

Background: Relationship between olive oil consumption and low cardiovascular mortality and mobility is the aim of current study. We were investigated of dietary virgin olive oil (VOO) effects on serum lipids profile. Methods: Experimental mature male rats were treated with VOO for 30 days at 0.25, 0.5 and 0.75 ml/kg/day and control group treated with saline at the same time via gastric gavage (n=6). At the end of day 30, serum cholesterol, triglycerides, HDL, LDL, VLDL levels and atherogenic indices were determined. Results: Analysis showed that main unsaturated fatty acid in VOO is oleic acid. After VOO administration, cholesterol, triglyceride, HDL and VLDL levels vs. control group increased significantly (P<0.05). The LDL levels were decreased by virgin olive oil in all doses in a dose dependent manner that in 0.75 ml/Kg/day vs. control group was significantly. Olive oil attenuated LDL/HDL ratio vs. control group significantly in a dose dependent manner (in 0.25, 0.5, and 0.75 ml/kg/day groups was 4.27±0.64, 3.85± 0.72, and 1.78±0.48, respectively vs. 8.55±0.2 mg/dl).VOO decrease TG/HDL ratio in 0.25 and 0.75 ml/kg/day (13.21± 1.07 and 12.45± 0.41 respectively vs. 16.51± 0.94 mg/dl). Conclusion: Result of this study showed that VOO can attenuate atherogenic indices possibly due to enrichment of this oil of oleic acid.
Habibolah Saadat, Seyed Ali Ziai, Sima Nasri, Mina Sakenshaft, Atefe Ansarian,
Volume 13, Issue 4 (1-2010)
Abstract

Introduction: Angiotensin converting enzyme (ACE) is an exopeptidase that converts Angiotensin I to Angiotensin II. Angiotensin II is a potent vasoconstrictor and releases aldosterone, and have a critical role in hypertension. In this study, ACE insertion / deletion (I/D) polymorphism and ACE activity was determined in patients with coronary artery disease (CAD) and normal subjects. The correlation of these parameters with important CAD risk factors were also evaluated. Methods: 204 subjects were assigned to patients and normal groups based on their angiography results. Serum ACE activities were assayed by HPLC and I/D polymorphism were analyzed by PCR method. Important risk factors such as diabetes mellitus, hypertension, lipid profiles, ejection fraction, smoking and opium consumption were also recorded. Results: CAD was higher in DD genotype subjects (OR= 2.45 CI= 1.05-5.73), and ACE activity was about twice in DD compared to II genotypes. ACE activity was higher in hypertensives and diabetics in CAD group (p<0.001), but in the normal group it did not have any correlation with these risk factors. The rate of opium use was higher in ID and DD subjects. Conclusion: DD genotype is a risk factor for CAD and ACE activity is higher in this genotype. However, there is not any correlation between ACE activity and CAD.

Page 1 from 3    
First
Previous
1