OBJECTIVETo study the differences of cardiovascular system between men and women in response to exercise stress.

METHODSForty healthy youth were tested according to Bruce protocol of exercise stress. They were detected by ultrasonography during the rest, peak exercise, and recovery stages, respectively. The left ventricular diastolic elastance (Ed), effective arterial elastance (Ea), left ventricular end-systolic elatance (Ees), ventricular-vascular coupling index (VVI), and total stiffness index (TSI) were measured and calculated according to the formulas. The results of all stages were compared according to genders.

RESULTSAll stages, the Ed, TSI, and VVI of women were higher than those of men, but the Ees was lower than that of men (all P<0.05); there was no significant difference in Ea between men and women. The Ed, Ees, Ea, and TSI were closely related with left ventricular oxygen consumption and heart function, and women showed more closely. Before and after exercise, the changes were different in Ed, Ees, Ea, TSI, and VVI (all P<0.05), and VVI changed least.

CONCLUSIONSBefore and after exercise, the ventricular stiffness matched well with arterial stiffness and maintained within a narrow range. For women, the tolerance of exercise was lower than that of men.

Adult ; Diastole ; physiology ; Exercise ; physiology ; Female ; Humans ; Male ; Sex Characteristics ; Vascular Resistance ; physiology ; Vascular Stiffness ; physiology ; Ventricular Function, Left ; physiology

In order to study the cardiovascular hemodynamic characteristics and evaluate the blood pump, we made a series of cardiovascular simulation devices which could reflect the hemodynamics of blood circulation system by the elastic chamber model, and tested the relations between cardiovascular hemodynamic parameters (such as systole pressure, diastole pressure, average pressure, pulsative pressure, flow rate) and ventricular afterload (peripheral resistance and vascular compliance) as well as cardiac output, diastolic period, systole period and preload. The effect of the parameters on the arterial pressure and flow rate was estimated when any one of the parameters was changed. The result of simulating experiment was coincided with that deduced from mathematical model and physiologic condition. Therefore the series of cardiovascular simulation devices can reflect the hemodynamics of blood circulation.
Blood Pressure ; physiology ; Cardiac Output ; physiology ; Cardiovascular Physiological Phenomena ; In Vitro Techniques ; Models, Cardiovascular ; Vascular Resistance ; physiology

Mechanisms of acupuncture and moxibustion for treatment of hypertension have been studied extensively from poly-aspects, poly-levels and poly-links. The present paper reviews the studies on nervous regulation, humoral regulation and regulation of peripheral vessel resistance and other pathways and their relationships in recent ten years, and indicates further perfecting these studies from the following aspects: studies on the mechanism of section and combination of blood pressure-decreasing points, relationship of time-effect and dose-effect of acupuncture and moxibustion, and studies on mechanisms of functions of nerve-endocrine-immune system.
Acupuncture Therapy ; Brain ; physiology ; Endothelins ; physiology ; Humans ; Hypertension ; physiopathology ; therapy ; Moxibustion ; Neurotransmitter Agents ; physiology ; Peripheral Nerves ; physiology ; Renin-Angiotensin System ; physiology ; Vascular Resistance

Pulsatile blood flow plays an important role in maintaining normal vascular endothelial function. Quantitative measurement of pulsatility of artery blood pressure and blood flow in dogs and effects of enhanced external counterpulsation (EECP) on the pulsatility were taken in this study. Common carotid artery blood pressure and blood flow were measured in 6 beagle dogs that had suffered from an acute myocardial infarction 6 weeks before. A 6F tip transducer catheter was inserted into the right common carotid artery to measure blood pressure, and blood flow was measured in the left common carotid artery by an electromagnetic blood flow probe under anesthesia before and during EECP. Blood pulse pressure, pulsatility index (ratio of peak pressure to end diastolic pressure) and standard deviation of blood pressure were calculated to evaluate the pulsatility of arterial blood pressure. Blood pulse flow, pulsatility index (ratio of peak flow to trough flow) and standard deviation of blood flow were calculated to evaluate the pulsatility of blood flow. Mean vascular resistance (MVR) was calculated as MVR = mean blood pressure/mean blood flow. Blood pulse pressure, pulsatility index and standard deviation of blood pressure were elevated from 30 +/- 9 mmHg, 1.26 +/- 0.05 and 8.7 +/- 2.5 mmHg to 43 +/- 8 mmHg (P < 0.05), 1.54 +/- 0.13 and 12.4 +/- 2.0 mmHg (P < 0.05) before and during EECP, respectively. Blood pulse flow, pulsatility index and standard deviation of blood flow were elevated from 317 +/- 48 ml/min, 2.85 +/- 0.21 and 96 +/- 21 ml/min to 447 +/- 88 ml/min, 4.56 +/- 0.90 and 131 +/- 39 ml/min before and during EECP (P < 0.05). MVR was decreased from 578 +/- 72 before EECP to 476 +/- 85 Wood units during EECP(P < 0.05). These data demonstrate that EECP gives an elevation of pulsatility to blood pressure and blood flow, thus it may lead to the decrease of vascular resistance.
Animals ; Blood Pressure ; Carotid Arteries ; physiology ; Counterpulsation ; Dogs ; Hemodynamics ; Pulsatile Flow ; Regional Blood Flow ; Vascular Resistance

Portal hypertension (PHT) is associated with changes in the intrahepatic, systemic and portosystemic collateral circulations. Alteration in vasoreactivity (vasodilation and vasoconstriction) plays a central role in the pathogenesis of PHT by contributing to increased intrahepatic resistance, hyperdynamic circulation and the expansion of the collateral circulation. PHT is also importantly characterized by changes in vascular structure; termed vascular remodeling, which is an adaptive response of the vessel wall that occurs in response to chronic changes in the environment such as shear stress. Angiogenesis, the sprouting of new blood vessels, also occurs in PHT, especially in the expansion of the portosystemic collateral circulation. These complementary processes of vasoreactivity, vascular remodeling and angiogenesis represent important targets in the research for the treatment of portal hypertension.
Collateral Circulation/physiology ; Endothelial Cells/metabolism ; Hepatic Stellate Cells/metabolism ; Humans ; Hypertension, Portal/*etiology ; Liver Circulation/physiology ; Vascular Resistance

AIMThrough studying local regulatory mechanisms in pulmonary arteries (PA) and thoracic aortae (TA) under simulated microgravity (SM), to collect some data for the researches of adaptive mechanisms in pulmonary and systemic arteries and for the mechanisms accounting for orthostatic intolerance after SM.

METHODSCardiopulmonary circulatory function during 7-day 6 degrees head down bed rest (HDT) in male young volunteers was measured with a XXH-2000 pulmonary circulation and cardiac function instrument. - 30 degrees C tail suspended (TS) rats were used as the model to simulate the physiological effects of M. The PA and TA changes of vasoreactivity were respectively observed by vitro vessel rings perfusion.

RESULTSThe changes in volume of PA and pulmonary vein during a cardiac cycle and the preload in left cardiac ventricle in men increased significantly in the initial HDT. The super-regulatory phenomena appeared in both pulmonary and systemic circulation, but earlier and more obviously in pulmonary circulation than systemic circulation during 96-144 h. The dilatory reactivity in TS7 PA increased significantly, tended to decrease in TS14. The dilatory reactivity of TA in TS7 had a significant increase, had a slight increase in TS14. The contractile reactivity of PA decreased slightly in TS7 from CON, and were attenuated significantly in TS14. The contractile reactivity of TA in TS14 decreased significantly. The responsiveness to KCl, phenylephrine and sodium nitroprusside in VEC- removed PA had no differences among all groups.

CONCLUSIONThe differences in changes between pulmonary and systemic arteries under SM could be an important sign of depressed local regulatory function, which might be mainly due to dilatory function in VEC and contribute to the occurrence of orthostatic intolerance after SM.

Animals ; Aorta, Thoracic ; physiology ; Humans ; Male ; Pulmonary Artery ; physiology ; Rats ; Rats, Wistar ; Vascular Resistance ; Weightlessness ; Weightlessness Simulation ; Young Adult

Pulse waves contain abundant physiological and pathological information of human body. Research of the relationship between pulse wave and human cardiovascular physiological parameters can not only help clinical diagnosis and treatment of cardiovascular diseases, but also contribute to develop many new medical instruments. Based on the traditional double elastic cavity model, the human cardiovascular system was established by using the electric network model in this paper. The change of wall pressure and blood flow in artery was simulated. And the influence of the peripheral resistance and vessel compliance to the distribution of blood flow in artery was analyzed. The simulation results were compared with the clinical monitoring results to predict the physiological and pathological state of human body. The result showed that the simulation waveform of arterial wall pressure and blood flow was stabile after the second cardiac cycle. With the increasing of peripheral resistance, the systolic blood pressure of artery increased, the diastolic blood pressure had no significant change, and the pulse pressure of artery increased gradually. With the decreasing of vessel compliance, the vasoactivity became worse and the pulse pressure increased correspondingly. The simulation results were consistent with the clinical monitoring results. The increasing of peripheral resistance and decreasing of vascular compliance indicated that the incidence of hypertension and atherosclerosis was increased.
Aorta ; Arteries ; physiology ; Atherosclerosis ; Blood Pressure ; Cardiovascular Diseases ; Electricity ; Heart ; physiology ; Hemodynamics ; Humans ; Hypertension ; Models, Cardiovascular ; Vascular Resistance

BACKGROUND/AIMS: Despite the clinical importance and widespread use of pulse wave velocity (PWV), there are no standards for pulse sensors or for system requirements to ensure accurate pulse wave measurement. We assessed the reproducibility of PWV values using a newly developed PWV measurement system. METHODS: The system used in this study was the PP-1000, which simultaneously provides regional PWV values from arteries at four different sites (carotid, femoral, radial, and dorsalis pedis). Seventeen healthy male subjects without any cardiovascular disease participated in this study. Two observers performed two consecutive measurements in the same subject in random order. To evaluate the reproducibility of the system, two sets of analyses (within-observer and between-observer) were performed. RESULTS: The means+/-SD of PWV for the aorta, arm, and leg were 7.0+/-1.48, 8.43+/-1.14, and 8.09+/-0.98 m/s as measured by observer A and 6.76+/-1.00, 7.97+/-0.80, and 7.97+/-0.72 m/s by observer B, respectively. Betweenobserver differences for the aorta, arm, and leg were 0.14+/-0.62, 0.18+/-0.84, and 0.07+/-0.86 m/s, respectively, and the correlation coefficients were high, especially for aortic PWV (r=0.93). All the measurements showed significant correlation coefficients, ranging from 0.94 to 0.99. CONCLUSIONS: The PWV measurement system used in this study provides accurate analysis results with high reproducibility. It is necessary to provide an accurate algorithm for the detection of additional features such as flow wave, reflection wave, and dicrotic notch from a pulse waveform.
Adult ; Blood Flow Velocity/*physiology ; Carotid Arteries/*physiology ; Femoral Artery/*physiology ; Foot/*blood supply ; Humans ; Male ; Middle Aged ; Radial Artery/*physiology ; Reference Values ; Regional Blood Flow/*physiology ; Reproducibility of Results ; Vascular Diseases/diagnosis ; Vascular Resistance/physiology ; Young Adult

A new method for constructing the model of vascular trees was proposed in this paper. By use of this method, the arterial trees in good agreement with the actual structure could be grown. In this process, all vessels in the vascular tree were divided into two groups: the conveying vessels, and the delivering branches. And different branches could be built by different ways. Firstly, the distributing rules of conveying vessels were ascertained by use of measurement data, and then the conveying vessels were constructed in accordance to the statistical rule and optimization criterion. Lastly, delivering branches were modeled by constrained constructive optimization (CCO) on the conveying vessel-trees which had already been generated. In order to compare the CCO method and stepwise method proposed here, two 3D arterial trees of human tongue were grown with their vascular tree having a special structure. Based on the corrosion casts of real arterial tree of human tongue, the data about the two trees constructed by different methods were compared and analyzed, including the averaged segment diameters at respective levels, the distribution and the diameters of the branches of first level at respective directions. The results show that the vascular tree built by stepwise method is more similar to the true arterial of human tongue when compared against the tree built by CCO method.
Algorithms ; Arteries ; anatomy & histology ; physiology ; Blood Pressure ; physiology ; Computer Simulation ; Hemodynamics ; physiology ; Humans ; Imaging, Three-Dimensional ; Models, Cardiovascular ; Vascular Resistance ; physiology

The present study was designed to investigate the effects of high-saturated and high-unsaturated fatty acid diets on relaxation and contraction of the renal arteries in insulin resistance (IR) rats. Wistar rats were fed normal chow diet (control), high-saturated fatty acid diet or high-unsaturated fatty acid diet for 6 months (n=14 in each group). IR was evaluated by glucose infusion rate (GIR) of hyperinsulinemic euglycemic clamp. Blood pressure was measured via the tail-cuff method. Body weight (BW), plasma total triglyceride (TG), free fatty acid (FFA), insulin, fasting blood glucose (FBG) and nitric oxide metabolite (NO2(-)/NO3(-)) were compared among the three groups. The rats were sacrificed and the renal arterial rings were placed in the physiological tissue baths for measurement of vascular response to various agents. After the arterial rings were constricted with 3 mmol/L noradrenaline (NA), endothelium-dependent vasorelaxation to acetylcholine (ACh) and endothelium-independent vasorelaxation to sodium nitroprusside (NTP) were measured. Endothelium-dependent vasorelaxation to ACh was also observed in renal arterial rings incubated with L-arginine (L-Arg), N(omega)-nitro-L-arginine (L-NNA) and methylene blue (MB), respectively. Arterial contractility was evaluated from concentration-response curves to 10 nmol/L-100 micromol/L NA. Saturated or unsaturated fatty acids led to moderate rises in blood pressure (P<0.05). It was associated with higher levels of plasma lipids and lower whole body insulin sensitivity (P<0.01). There were no significant differences in BW, FBG, TG, insulin and FFA between saturated and unsaturated fatty acid-fed rats. A decrease in endothelium-dependent vasorelaxation of the renal arteries in saturated and unsaturated fatty acid-fed rats was observed (P<0.01), but there was no marked difference between the two high-fatty acid diet groups. Endothelium-dependent vasorelaxation was increased when the arteries were incubated with L-Arg and decreased when incubated with L-NNA and MB in both high-fatty acid diet groups (P<0.05, P<0.01). But no difference was found before and after incubation with L-Arg, L-NNA and MB in the control rats. In the mean time, endothelium-independent maximal vasorelaxation response of renal arteries to NTP and renal arterial contractile responses to cumulative dose of NA were assayed, and there was no difference among the three groups (P>0.05). Endothelium-dependent vasorelaxation was negatively correlated with systolic blood pressure and TG, and positively correlated with NO2(-)/NO3(-) and GIR. There was a significantly negative correlation between FFA and NO2(-)/NO3(-). The present study suggests that both high-saturated and unsaturated fatty acid diets result in hypertension associated with significantly decreased endothelium-dependent vasorelaxation, dyslipidemia and IR, and that decreased endothelium-dependent vasorelaxation induced by high fatty acid diets is associated with impaired L-Arg-NO-cGMP pathways.
Animals ; Dietary Fats, Unsaturated ; administration & dosage ; Endothelium, Vascular ; physiology ; Fatty Acids ; administration & dosage ; Insulin Resistance ; Male ; Nitric Oxide ; physiology ; Rats ; Rats, Wistar ; Renal Artery ; physiology ; Systole ; Vasoconstriction ; Vasodilation