OBJECTIVETo evaluate the effects of polyethylene oxide (PEO) on blood perfusion in hind limb skeletal muscles in a rat model of chronic hind limb ischemia.

METHDOSTwelve rat models of chronic hind limb ischemia established by unilateral femoral artery ligation were randomized into PEO and control groups (n=6) and treated with intravenous infusion of PEO and saline through the internal jugular vein every other day for 2 weeks. Contrast-enhanced ultrasonography was performed after the treatments to evaluate the blood flow in the skeletal muscles at different time points and blood flow reserve in the ischemic hind limbs on day 28.

RESULTSStarting from 7 days after femoral artery ligation, blood flow in the ischemic hind limb skeletal muscles was significantly higher in PEO group than in the control group (P<0.05). On day 28, blood flow reserve in the ischemic hind limb was significantly higher (P=0.012), and blood volume was significantly increased in PEO group as compared that in the control group (P=0.024).

CONCLUSIONSPEO can increase blood flow, blood flow reserve and vascular volume in the hind limb skeletal muscles in rats with chronic hind limb ischemia, suggesting that PEO can promote angiogenesis and arterial formation by increasing blood flow shear stress to improve blood supply of ischemic hind limbs.

OBJECTIVETo study value of velocity vector imaging (VVI) in assessment of normal left ventricular diastolic function and the corresponding reference values.

METHODSNinety-seven healthy subjects were selected by combined clinical, ultrasound, and NT-proBNP examinations. Using a Siemens Acuson Sequoia C512 echocardiograph, VVI was adopted to examine the myocardial early diastolic velocity (E) of the septal, lateral, anterior, inferior, anterior septum, and posterior wall of the left ventricle at the level of mitral annulus. The images were analyzed for VVI and the mean diastolic velocity (E(m)) and hence the E/E(m) ratio was calculated based on the offline workstation interface.

RESULTSThe reference range of E/E(m) ratio derived from the data of the 97 healthy subjects was (unilateral boundaries with 95% limit) and (1, 22.935), was (1, 22.300) in male subjects and (1, 24.766) in female subjects. The reference E/E(m) range was (0, 22.413) in male subjects under 50 years of age, (1, 24.766) in female subjects under 50 years, (1, 22.300) in male subjects over 50 years, and (1, 24.766) in female subjects over 50 years.

CONCLUSIONVVI is a good method for non-invasive evaluation of the left ventricular diastolic function and provides an accurate and reliable means for clinical assessment of the left ventricular diastolic function.

Adolescent ; Adult ; Aged ; Blood Flow Velocity ; physiology ; Diastole ; physiology ; Echocardiography ; methods ; Female ; Humans ; Male ; Middle Aged ; Reference Values ; Ventricular Function, Left ; physiology ; Young Adult

OBJECTIVETo investigate the drag-reducing effect of polyethylene oxide (PEO) on the velocity of red blood cells in rat cremaster microcirculation.

METHODSBlood samples were collected from 6 Wistar male rats (100-110 g) via the post-orbital venous plexus. The red blood cells were separated by centrifugation and labeled by fluorescinisothiocyate (FITC). After successful establishment of cremaster model, the labeled red blood cells were injected into the jugular vein, and the microcirculation was observed and recorded under fluorescence microscope. The hemodynamic parameters and microcirculation video was recorded every 4 min since 4 min before PEO or normal saline injection. Both PEO (10 ppm) and normal saline was injected into the same rat in random sequence at a constant rate of 3.5 ml/h for 20 min followed by observation for another 20 min. The velocity of the labeled-red blood cells was determined by IPP 6.0 software.

RESULTSCompared with normal saline, PEO significantly increased the velocity of the red blood cells in the rat cremaster microcirculation (498.7-/+182.89 microm/s vs 773.54-/+308.27 microm/s, P=0.012). No significant changes in the heart rate and arterial blood pressure were observed during the experiment (P=0.836, P=0.420).

CONCLUSIONPEO at an extremely low concentration can significantly increase the velocity of the red blood cells in rat cremaster microcirculation and produces no significant impact on heart rate and arterial blood pressure.

Animals ; Blood Flow Velocity ; drug effects ; Male ; Microcirculation ; drug effects ; physiology ; Muscle, Smooth ; blood supply ; Polyethylene Glycols ; pharmacology ; Rats ; Rats, Wistar ; Testis

OBJECTIVETo observe the effect of polyethylene oxide (PEO) solution at different concentrations on abdominal aortic blood flow and vascular resistance in rats and evaluate the safety and drag-reducing effect of PEO solution.

METHODSThirty-two rats were anesthetized and randomly divided into 4 groups. An ultrasonic flow probe was deployed on the abdominal aorta (5 mm above the common iliac artery) to measure the blood flow. The carotid artery pressure, iliac artery pressure, iliac vein pressure, central venous pressure (CVP) and ECG were also monitored. Saline or different concentrations of PEO [(1x10(-6)(low), 1x10(-5)(middle) and 5x10(-5)(high) g/ml)] were injected in the 4 groups of rats through the caudal vein at a constant rate of 5 ml/h for 20 min, and the changes of the vascular resistance was observed. RESULTS After injections of 1x10(-6) and 1x10(-5) g/ml PEO, the abdominal aortic flow increased significantly (P<0.05) while the vascular resistance was reduced (P(low)=0.052, P(middle)<0.001) as compared to those in the saline control group. Following the injection with 5x10(-5) g/ml PEO, the abdominal aortic flow increased to a threshold in the initial 4 min, after which it rapidly decreased to approach the baseline levels despite continuous infusion. Blood pressure remained stable after the injections except for 5x10(-5) g/mlPEO injection, which resulted in a reduction of the blood pressure by about 10 mmHg (P=0.014). The heart rate and CVP both underwent no significant changes following the injections.

CONCLUSIONThe drag-reducing effect of PEO is closely related to its concentration, and compared with 1x10(-6) g/ml, 1x10(-5) g/ml PEO more effectively increases the blood flow and decreases the resistance. The effectiveness and safety of EPO are attenuated at a concentration higher than 5x10(-5) g/ml.

Animals ; Aorta, Abdominal ; physiology ; Blood Flow Velocity ; drug effects ; Dose-Response Relationship, Drug ; Male ; Polyethylene Glycols ; pharmacology ; Random Allocation ; Rats ; Rats, Wistar ; Vascular Resistance ; drug effects

OBJECTIVETo investigate the impact of high-dose microbubbles induced by high mechanical index myocardial contrast echocardiography (MCE) on vascular permeability and its recovery time in rats.

METHODSThirty male Wistar rats were randomized into 4 MCE groups (groups A-D) and a control group. In the MCE groups, Evans blue was injected at 10 s before MCE (A), immediately after the end of MCE (B), and at 5 min (C) and 20 min after the end of MCE (D). In the control group, the microbubbles and Evans blue were injected at the end of a 5-min ultrasound exposure. All the rats were sacrificed 5 min after Evans blue injection, and the content of Evans blue in the myocardium and the percentage of Evans blue leakage area were determined.

RESULTSThe percentage of Evans blue leakage area in groups A, B and C were significantly higher than that in the control group (P<0.05), while the percentage was similar between group D and the control group (P>0.05). Evans blue contents in groups A and B were significantly higher than that in the control group (P<0.05), but groups C and D showed comparable contents with the control group E (P>0.05). No significant changes of the heart rates and premature beat number were observed during and after MCE in these groups (P>0.05).

CONCLUSIONHigh mechanical index MCE and a high contrast dose may induce increased microvascular leakage in rats, and the vascular permeability can recover in 20 min after MCE.

Animals ; Capillary Permeability ; drug effects ; Contrast Media ; pharmacology ; Coronary Vessels ; physiopathology ; Echocardiography ; Male ; Microbubbles ; Rats ; Rats, Wistar

OBJECTIVETo evaluate the changes of cerebral blood flow (CBF) with real-time contrast-enhanced ultrasound (CEU) in a canine model of acute cerebral ischemia.

METHODSCerebral perfusion was assessed in 6 dogs subjected to craniotomy with CEU at the time of 0, 30, 60, 90 and 120 min after occlusion of the left common carotid artery (LCCA). The microvascular volume (A) and blood flow velocity (beta) in the brain were measured from the time-versus-acoustic intensity plots, and the value of Axbeta were calculated. 99mTc-ECD brain single photon emission computed tomography (SPECT) was performed on the day before the experiment and at 120 min after LCCA occlusion. The radioactive counts on both sides of the cerebral cortex were calculated.

RESULTSA significant correlation was found between Axbeta from CEU and volume of the blood flow of the CCA from Doppler flowmetry. A, beta and Axbeta values varied significantly between the different time points (P>0.001). The ipsilateral hemisphere showed a low-perfusion state while the contralateral hemisphere showed a high-perfusion state immediately after the occlusion.

CONCLUSIONSThe changes of beta is the main regulation mechanism during acute cerebral ischemia in dogs.

Animals ; Blood Flow Velocity ; Brain ; blood supply ; Brain Ischemia ; diagnostic imaging ; Cerebrovascular Circulation ; Dogs ; Male ; Regional Blood Flow ; Ultrasonography

OBJECTIVETo assess the value of velocity vector imaging (VVI) and quantitative tissue velocity imaging (QTVI) in assessing left ventricular diastolic function of the dogs with acute myocardial ischemia.

METHODSSix healthy mongrel dogs were subjected to ligation of the left circumflex artery or left anterior descending artery to induce coronary artery stenosis of varying degrees. The mean peak diastolic velocity (Em) of the ventricular walls around the mitral annulus was recorded with VVI or QTVI in the coronary blood flow. The left ventricular end diastolic pressure (LVEDP) was measured with pigtail catheter in the left ventricle.

RESULTSAs the coronary blood flow decreased, LVEDP was gradually increased, and Em measured by VVI or QTVI were also gradually decreased. A good linear correlation was shown between Em measured by VVI or QTVI and LVEDP (r=-0.834, P<0.001, and r=-0.68, P<0.001, respectively). A significant difference was observed in the correlation coefficient between VVI and QTVI (Z=2.625, P=0.0087).

CONCLUSIONVVI and QTVI both provide good noninvasive means for measuring left ventricular diastolic function. VVI, a new echocardiographic modality without angular dependence, is better than QTVI in evaluating left ventricular diastolic function.

Animals ; Disease Models, Animal ; Dogs ; Echocardiography ; methods ; Male ; Myocardial Ischemia ; diagnostic imaging ; physiopathology ; Ventricular Function, Left

OBJECTIVETo investigate the feasibility of bone marrow mesenchymal stem cell (MSC) transplantation with ultrasound-targeted microbubble destruction.

METHODSTwenty-one Wistar rats were divided into MSCs-iv group (MSCs-iv), ultrasound+MSCs-iv group (US+MSCs-iv), ultrasound+microbubble+MSCs-iv group (US+MB+MSCs-iv) with intravenous MSC transfer, ultrasound and microbubble treatment as indicated. The skeletal muscles were obtained from the rats for microscopic examination with HE staining. The hindlimb gracilis and semimembranosus muscles were sampled 7 days after MSC transplantation, and the transplanted MSCs were detected by immunohistochemistry. The vital organs were collected from rats in US+MB+MSCs-iv group for immunohistochemistry.

RESULTSIn US+MB+MSCs-iv group, HE staining demonstrated the presence of red blood cell leakage into the tissue space in the gracilis and semimembranosus muscles, and immunohistochemistry identified large numbers of transplanted MSCs in the the gracilis and semimembranosus muscles and the spleen, whereas no labeled cells were detected in the skeletal muscles in other groups.

CONCLUSIONUltrasound-targeted microbubble destruction provides a useful means for enhancing the efficiency of stem cell transplantation.

Animals ; Bone Marrow Cells ; cytology ; Cell Movement ; radiation effects ; Female ; Male ; Mesenchymal Stem Cell Transplantation ; methods ; Mesenchymal Stromal Cells ; cytology ; Microbubbles ; Muscle, Skeletal ; cytology ; Rats ; Rats, Wistar ; Ultrasonics

Objective To validate the efficacy of velocity vector imaging (VVI) and quantitative tissue velocity imaging (QTVI) for evaluating left ventricular diastolic function. Methods Fifty-one patients underwent left heart catheterization were included in this study. Mean of peak early diastolic velocity (Em), EF and the ratio of early (E) to late (A) mitral valve flow velocity (E/A) were measured by echocardiography and the ratio of E to Em (E/Em) was calculated. Left ventricular end diastolic pressure (LVEDP) was measured during catheterization examination. Results E/Em derived from VVI or QTVI was significantly correlated with LVEDP(r=0. 808, P<0.01 and r=0.692, P<0.01, respectively) and the correlation coefficient between VVI and LVEDP was significantly higher than that between QTVI and LVEDP (Z=2.246, P=0.025). Em derived from VVI and QTVI also negatively correlated with LVEDP (r= -0.740, P<0.01 and r=-0.567, P<0.01)and the correlation coefficient between VVI and LVEDP was significantly higher than that between QTVI and LVEDP (Z=2.595, P=0.009). However, there was no correlation between E/A and LVEDP (r=0.117, P=0.415). Conclusion E/Em and Em derived from VVI and QTVI are valuable parameters for evaluating LV diastolic function.

OBJECTIVETo evaluate the direct effects of dobutamine as compared to adenosine on the coronary microcirculation in both normal and stenotic segments using myocardial contrast echocardiography (MCE).

METHODSLeft anterior descending (LAD) coronary artery stenosis, which was not flow limiting at rest, was established in 9 dogs. At the baseline and during intracoronary infusion of dobutamine (2 mg.kg(-1).min(-1)) and adenosine (5 mg.kg(-1).min(-1)), the radiolabeled microsphere (RM)-derived myocardial blood flow (MBF) were determined, and the double product (DP) and myocardial vascular resistance (MVR) were calculated. MCE was performed to determine the myocardial blood volume (MBV, represented by A) and microbubble velocity (beta).

RESULTSAs compared to the baseline level, the MBF increased and MVR decreased significantly in both the normal and abnormal beds during infusion of both drugs (P<0.05). In the normal bed, adenosine had no effect on MBV, the decrease in MVR was the result of decreased arteriolar (plus venular) resistance, and the increase in MBF was predominately due to the increase in b (deltabeta/ deltaA=13.6). Dobutamine caused a 28% increase in MBV, responsible for 32% of the decrease in the total MVR, but the increase in MBF arose mainly from the increase in b (deltabeta/deltaA=5.9). In the abnormal bed, both the drugs caused a similar increase in MBF entirely by increasing b, and 14% and 15% of the increases in capillary resistance were associated with the capillary derecruitment during administration of dobutamine and adenosine, respectively.

CONCLUSIONThe direct effects of intracoronary dobutamine infusion on the coronary microcirculation are similar to that of adenosine, and the increase in MBF occurs mostly as the result of increased myocardial blood velocity.

Adenosine ; pharmacology ; Adrenergic beta-Agonists ; pharmacology ; Animals ; Blood Flow Velocity ; drug effects ; Coronary Circulation ; drug effects ; Coronary Stenosis ; diagnostic imaging ; Coronary Vessels ; diagnostic imaging ; Dobutamine ; pharmacology ; Dogs ; Echocardiography ; methods ; Microcirculation ; drug effects ; Vasodilator Agents ; pharmacology