Science.gov

Sample records for arterial baroreceptor function

  1. Role of arterial baroreceptors in mediating cardiovascular response to exercise

    NASA Technical Reports Server (NTRS)

    Mcritchie, R. J.; Vatner, S. F.; Patrick, T. A.; Braunwald, E.; Boettcher, D.; Heyndrickx, G. R.

    1976-01-01

    Experiments were conducted to define the role of the major arterial baroreceptors during moderately severe exercise by comparing the responses of untethered conscious dogs instrumented for the measurement of aortic pressure and cardiac output with those of dogs with total arterial baroreceptor denervation. The reflex heart rate responses to intravenous bolus doses of methoxamine were also examined in intact animals, both at rest and during exercise. Methoxamine is found to cause striking bradycardia at rest, but little bradycardia during exercise. Experimental findings suggest that the arterial baroreceptor reflex is normally inhibited during severe exercise and therefore plays little role in modulating the cardiovascular response to exercise.

  2. Role of arterial baroreceptors in mediating cardiovascular response to exercise

    NASA Technical Reports Server (NTRS)

    Mcritchie, R. J.; Vatner, S. F.; Patrick, T. A.; Braunwald, E.; Boettcher, D.; Heyndrickx, G. R.

    1976-01-01

    Experiments were conducted to define the role of the major arterial baroreceptors during moderately severe exercise by comparing the responses of untethered conscious dogs instrumented for the measurement of aortic pressure and cardiac output with those of dogs with total arterial baroreceptor denervation. The reflex heart rate responses to intravenous bolus doses of methoxamine were also examined in intact animals, both at rest and during exercise. Methoxamine is found to cause striking bradycardia at rest, but little bradycardia during exercise. Experimental findings suggest that the arterial baroreceptor reflex is normally inhibited during severe exercise and therefore plays little role in modulating the cardiovascular response to exercise.

  3. Arterial baroreceptor input contributes to long-term control of blood pressure.

    PubMed

    Thrasher, Terry N

    2006-06-01

    A little more than three decades ago, there was little doubt that baroreceptors were crucial for both the short-term and long-term control of mean arterial blood pressure (MAP). Then, in 1970 it was reported that baroreceptors reset completely within 48 hours in hypertensive rats. Three years later, it was reported that MAP was near normal in dogs with both aortic and carotid baroreceptors denervated based on continuous measurements, thus discrediting numerous reports of denervation-induced hypertension. These two observations quickly led to a reevaluation of the importance of baroreceptor input in long-term control mechanisms. Finally, a consensus emerged that baroreceptor input could not be involved in long-term control of MAP, and this conclusion can be found in all modern textbooks of physiology used in the instruction of medical students. However, recent experimental observations have challenged the conclusion that baroreceptor input plays no role in the long-term control of MAP. In this article, the principal arguments against baroreceptor involvement in long-term control of MAP are summarized, and the new findings that suggest that a reappraisal of our current concept is required are reviewed.

  4. [Influence of vascular surgery on baroreceptors of carotid artery and blood pressure--a literature review].

    PubMed

    Pasternak-Swirska, Marta; Krefftk, Michał; Witkiewicz, Wojciech

    2013-01-01

    According to available literature, surgical interventions and endovascu. lar treatment of carotid artery affect the function of baroreceptors located in carotid sinus. Consequently, intraoperational and in the perioperative period abnormal pressure control is noted, as well as fixed changes in blood pressure homeostasis. The study collected and discusses and the results of the latest research on this subject. The level of severity of baroreflex dysfunction is pronounced differently depending on whether the patient was subjected to conventional endarterectomy, eversion technique endarterectomy, angioplasty or stenting with the best result in the latter. Some authors suggest that stenting procedure may cause changes in the mechanical properties of carotid artery wall and thus increases the sensitivity of the baroreflex. The literature also points to a different effect depending on whether surgery was one or both sides of a lot worse pressure control after bilateral surgery. Frequently recorded the influence of procedures on disorder of vascular heart rate. There are also reports of a significant drop in pressure after stenting and carotid angioplasty with its neurological consequences, as well as an increase in blood pressure and hyperperfusion syndrome. An important observation is the occurrence of changes in blood pressure during surgery now due to mechanical stimulation of baroreceptors, which entails the consequences in the postoperative course.

  5. Estimation of arterial and cardiopulmonary total peripheral resistance baroreflex gain values: validation by chronic arterial baroreceptor denervation.

    PubMed

    Mukkamala, Ramakrishna; Kim, Jong-Kyung; Li, Ying; Sala-Mercado, Javier; Hammond, Robert L; Scislo, Tadeusz J; O'Leary, Donal S

    2006-05-01

    Feedback control of total peripheral resistance (TPR) by the arterial and cardiopulmonary baroreflex systems is an important mechanism for short-term blood pressure regulation. Existing methods for measuring this TPR baroreflex mechanism typically aim to quantify only the gain value of one baroreflex system as it operates in open-loop conditions. As a result, the normal, integrated functioning of the arterial and cardiopulmonary baroreflex control of TPR remains to be fully elucidated. To this end, the laboratory of Mukkamala et al. (Mukkamala R, Toska K, and Cohen RJ. Am J Physiol Heart Circ Physiol 284: H947-H959, 2003) previously proposed a potentially noninvasive technique for estimating the closed-loop (dimensionless) gain values of the arterial TPR baroreflex (GA) and the cardiopulmonary TPR baroreflex (GC) by mathematical analysis of the subtle, beat-to-beat fluctuations in arterial blood pressure, cardiac output, and stroke volume. Here, we review the technique with additional details and describe its experimental evaluation with respect to spontaneous hemodynamic variability measured from seven conscious dogs, before and after chronic arterial baroreceptor denervation. The technique was able to correctly predict the group-average changes in GA and GC that have previously been shown to occur following chronic arterial baroreceptor denervation. That is, reflex control by the arterial TPR baroreflex was virtually abolished (GA = -2.1 +/- 0.6 to 0.3 +/- 0.2; P < 0.05), while reflex control by the cardiopulmonary TPR baroreflex more than doubled (GC = -0.7 +/- 0.4 to -1.8 +/- 0.2; P < 0.05). With further successful experimental testing, the technique may ultimately be employed to advance the basic understanding of TPR baroreflex functioning in both humans and animals in health and disease.

  6. Arterial baroreceptors and brain histamine contribute to bradycardia to peripheral hyperosmolality.

    PubMed

    Kenney, M J; Bealer, S L

    1993-10-01

    The purpose of this study was to determine whether the bradycardic response to peripheral hyperosmolality in conscious rats is dependent on afferent baroreceptor mechanisms and whether central histamine H2 receptors play a role in baroreflex-mediated changes in heart rate (HR). Mean arterial pressure (MAP) and HR were recorded continuously during a 30-min infusion of 2.5 M NaCl (10 microliters.100 g-1.min-1) hypertonic saline (HTS). HTS infusion significantly increased MAP (21 +/- 4 mmHg) and reduced HR (-62 +/- 10 beats/min) in rats with intact arterial baroreceptors. In sinoaortic-denervated rats, HR remained unchanged from control despite a significant increase in MAP. After intracerebroventricular (lateral ventricle) administration of cimetidine or ranitidine (H2-receptor antagonists) in intact rats, HTS infusion significantly increased MAP (19 +/- 2 and 17 +/- 2 mmHg, respectively) but the bradycardia was abolished (-12 +/- 10 and -10 +/- 10 beats/min, respectively). In contrast, central H2-receptor blockade did not alter reflex HR responses to the intravenous administration of phenylephrine and nitroprusside or to the central administration of histamine or angiotensin II. These results indicate that the bradycardic response to HTS infusion is mediated through the arterial baroreceptor reflex and involves in part a selective histaminergic pathway.

  7. Bionic baroreceptor corrects postural hypotension in rats with impaired baroreceptor.

    PubMed

    Hosokawa, Kazuya; Ide, Tomomi; Tobushi, Tomoyuki; Sakamoto, Kazuo; Onitsuka, Ken; Sakamoto, Takafumi; Fujino, Takeo; Saku, Keita; Sunagawa, Kenji

    2012-09-04

    Impairment of the arterial baroreflex causes orthostatic hypotension. Arterial baroreceptor sensitivity degrades with age. Thus, an impaired baroreceptor plays a pivotal role in orthostatic hypotension in most elderly patients. There is no effective treatment for orthostatic hypotension. The aims of this investigation were to develop a bionic baroreceptor (BBR) and to verify whether it corrects postural hypotension. The BBR consists of a pressure sensor, a regulator, and a neurostimulator. In 35 Sprague-Dawley rats, we vascularly and neurally isolated the baroreceptor regions and attached electrodes to the aortic depressor nerve for stimulation. To mimic impaired baroreceptors, we maintained intracarotid sinus pressure at 60 mm Hg during activation of the BBR. Native baroreflex was reproduced by matching intracarotid sinus pressure to the instantaneous pulsatile aortic pressure. The encoding rule for translating intracarotid sinus pressure into stimulation of the aortic depressor nerve was identified by a white noise technique and applied to the regulator. The open-loop arterial pressure response to intracarotid sinus pressure (n=7) and upright tilt-induced changes in arterial pressure (n=7) were compared between native baroreceptor and BBR conditions. The intracarotid sinus pressure-arterial pressure relationships were comparable. Compared with the absence of baroreflex, the BBR corrected tilt-induced hypotension as effectively as under native baroreceptor conditions (native, -39±5 mm Hg; BBR, -41±5 mm Hg; absence, -63±5 mm Hg; P<0.05). The BBR restores the pressure buffering function. Although this research demonstrated feasibility of the BBR, further research is needed to verify its long-term effect and safety in larger animal models and humans.

  8. Evidence for unloading arterial baroreceptors during low levels of lower body negative pressure in humans

    PubMed Central

    Fu, Qi; Shibata, Shigeki; Hastings, Jeffrey L.; Prasad, Anand; Palmer, M. Dean; Levine, Benjamin D.

    2009-01-01

    Low levels (i.e., ≤20 mmHg) of lower body negative pressure (LBNP) have been utilized to unload “selectively” cardiopulmonary baroreceptors in humans, since steady-state mean arterial pressure and heart rate (HR) have been found unchanged at such levels. However, transient reductions in blood pressure (BP), followed by reflex compensation, may occur without detection, which could unload arterial baroreceptors. The purposes of this study were to test the hypothesis that the arterial baroreflex is engaged even during low levels of LBNP and to determine the time course of changes in hemodynamics. Fourteen healthy individuals (age range 20–54 yr) were studied. BP (Portapres and Suntech), HR (ECG), pulmonary capillary wedge pressure (PCWP) or pulmonary artery diastolic pressure (PDP) and right atrial pressure (RAP) (Swan-Ganz catheter) and hemodynamics (Modelflow) were recorded continuously at baseline and −15- and −30-mmHg LBNP for 6 min each. Application of −15-mmHg LBNP resulted in rapid and sustained falls in RAP and PCWP or PDP, progressive decreases in cardiac output and stroke volume, followed subsequently by transient reductions in both systolic and diastolic BP, which were then restored through the arterial baroreflex feedback mechanism after ∼15 heartbeats. Additional studies were performed in five subjects using even lower levels of LBNP, and this transient reduction in BP was observed in three at −5- and in all at −10-mmHg LBNP. The delay for left ventricular stroke volume to fall at −15-mmHg LBNP was about 10 cardiac cycles. An increase in systemic vascular resistance was detectable after 20 heartbeats during −15-mmHg LBNP. Steady-state BP and HR remained unchanged during mild LBNP. However, BP decreased, while HR increased, at −30-mmHg LBNP. These results suggest that arterial baroreceptors are consistently unloaded during low levels (i.e., −10 and −15 mmHg) of LBNP in humans. Thus “selective” unloading of cardiopulmonary

  9. Vasopressin responses to unloading arterial baroreceptors during cardiac nerve blockade in conscious dogs

    NASA Technical Reports Server (NTRS)

    O'Donnell, C. P.; Keil, L. C.; Thrasher, T. N.

    1992-01-01

    We examined the relative contributions of afferent input from the heart and from arterial baroreceptors in the stimulation of arginine vasopressin (AVP) secretion in response to hypotension caused by thoracic inferior vena caval constriction (TIVCC). Afferent input from cardiac receptors was reversibly blocked by infusing 2% procaine into the pericardial space to anesthetize the cardiac nerves. Acute cardiac nerve blockade (CNB) alone caused a rise in mean arterial pressure (MAP) of 24 +/- 3 mmHg but no change in plasma AVP. If the rise in MAP was prevented by TIVCC, plasma AVP increased by 39 +/- 15 pg/ml, and if MAP was allowed to increase and then was forced back to control by TIVCC, plasma AVP increased by 34 +/- 15 pg/ml. Thus the rise in MAP during CNB stimulated arterial baroreceptors, which in turn compensated for the loss of inhibitory input from cardiac receptors on AVP secretion. These results indicate that the maximum secretory response resulting from complete unloading of cardiac receptors at a normal MAP results in a mean increase in plasma AVP of 39 pg/ml in this group of dogs. When MAP was reduced 25% below control levels (from 95 +/- 5 to 69 +/- 3 mmHg) by TIVCC during pericardial saline infusion, plasma AVP increased by 79 +/- 42 pg/ml. However, the same degree of hypotension during CNB (MAP was reduced from 120 +/- 5 to 71 +/- 3 mmHg) led to a greater (P less than 0.05) increase in plasma AVP of 130 +/- 33 pg/ml. Because completely unloading cardiac receptors can account for an increase of only 39 pg/ml on average in this group of dogs, the remainder of the increase in plasma AVP must be due to other sources of stimulation. We suggest that the principal stimulus to AVP secretion after acute CNB in these studies arises from unloading the arterial baroreceptors.

  10. Vasopressin responses to unloading arterial baroreceptors during cardiac nerve blockade in conscious dogs

    NASA Technical Reports Server (NTRS)

    O'Donnell, C. P.; Keil, L. C.; Thrasher, T. N.

    1992-01-01

    We examined the relative contributions of afferent input from the heart and from arterial baroreceptors in the stimulation of arginine vasopressin (AVP) secretion in response to hypotension caused by thoracic inferior vena caval constriction (TIVCC). Afferent input from cardiac receptors was reversibly blocked by infusing 2% procaine into the pericardial space to anesthetize the cardiac nerves. Acute cardiac nerve blockade (CNB) alone caused a rise in mean arterial pressure (MAP) of 24 +/- 3 mmHg but no change in plasma AVP. If the rise in MAP was prevented by TIVCC, plasma AVP increased by 39 +/- 15 pg/ml, and if MAP was allowed to increase and then was forced back to control by TIVCC, plasma AVP increased by 34 +/- 15 pg/ml. Thus the rise in MAP during CNB stimulated arterial baroreceptors, which in turn compensated for the loss of inhibitory input from cardiac receptors on AVP secretion. These results indicate that the maximum secretory response resulting from complete unloading of cardiac receptors at a normal MAP results in a mean increase in plasma AVP of 39 pg/ml in this group of dogs. When MAP was reduced 25% below control levels (from 95 +/- 5 to 69 +/- 3 mmHg) by TIVCC during pericardial saline infusion, plasma AVP increased by 79 +/- 42 pg/ml. However, the same degree of hypotension during CNB (MAP was reduced from 120 +/- 5 to 71 +/- 3 mmHg) led to a greater (P less than 0.05) increase in plasma AVP of 130 +/- 33 pg/ml. Because completely unloading cardiac receptors can account for an increase of only 39 pg/ml on average in this group of dogs, the remainder of the increase in plasma AVP must be due to other sources of stimulation. We suggest that the principal stimulus to AVP secretion after acute CNB in these studies arises from unloading the arterial baroreceptors.

  11. Aortic Baroreceptors Display Higher Mechanosensitivity than Carotid Baroreceptors

    PubMed Central

    Lau, Eva On-Chai; Lo, Chun-Yin; Yao, Yifei; Mak, Arthur Fuk-Tat; Jiang, Liwen; Huang, Yu; Yao, Xiaoqiang

    2016-01-01

    Arterial baroreceptors are mechanical sensors that detect blood pressure changes. It has long been suggested that the two arterial baroreceptors, aortic and carotid baroreceptors, have different pressure sensitivities. However, there is no consensus as to which of the arterial baroreceptors are more sensitive to changes in blood pressure. In the present study, we employed independent methods to compare the pressure sensitivity of the two arterial baroreceptors. Firstly, pressure-activated action potential firing was measured by whole-cell current clamp with a high-speed pressure clamp system in primary cultured baroreceptor neurons. The results show that aortic depressor neurons possessed a higher percentage of mechano-sensitive neurons. Furthermore, aortic baroreceptor neurons show a lower pressure threshold than that of carotid baroreceptor neurons. Secondly, uniaxial stretching of baroreceptor neurons, that mimics the forces exerted on blood vessels, elicited a larger increase in intracellular Ca2+ rise in aortic baroreceptor neurons than in carotid baroreceptor neurons. Thirdly, the pressure-induced action potential firing in the aortic depressor nerve recorded in vivo was also higher. The present study therefore provides for a basic physiological understanding on the pressure sensitivity of the two baroreceptor neurons and suggests that aortic baroreceptors have a higher pressure sensitivity than carotid baroreceptors. PMID:27630578

  12. Cardiopulmonary and arterial baroreceptor unloading during passive hyperthermia does not contribute to hyperthermia-induced hyperventilation

    PubMed Central

    Lucas, Rebekah A. I.; Pearson, James; Schlader, Zachary J.; Crandall, Craig G.

    2016-01-01

    This study tested the hypothesis that baroreceptor unloading during passive hyperthermia contributes to increases in ventilation and decreases in end-tidal partial pressure of carbon dioxide (PET,CO2) during that exposure. Two protocols were performed, in which healthy subjects underwent passive hyperthermia (increasing intestinal temperature by ~1.8°C) to cause a sustained increase in ventilation and reduction in PET,CO2. Upon attaining hyperthermic hyperventilation, in protocol 1 (n = 10; three females) a bolus (19 ± 2 ml kg−1) of warm (~38°C) isotonic saline was rapidly (5–10 min) infused intravenously to restore reductions in central venous pressure, whereas in protocol 2 (n = 11; five females) phenylephrine was infused intravenously (60–120 μg min−1) to return mean arterial pressure to normothermic levels. In protocol 1, hyperthermia increased ventilation (by 2.2 ± 1.7 l min−1, P < 0.01), while reducing PET,CO2 (by 4 ± 3 mmHg, P = 0.04) and central venous pressure (by 5 ± 1 mmHg, P <0.01). Saline infusion increased central venous pressure by 5 ± 1 mmHg (P < 0.01), restoring it to normothermic values, but did not change ventilation or PET,CO2 (P > 0.05). In protocol 2, hyperthermia increased ventilation (by 5.0 ± 2.7l min−1, P <0.01) and reduced PET ,CO2 (by 5 ± 2 mmHg, P < 0.01) and mean arterial pressure (by 9 ± 7 mmHg, P <0.01). Phenylephrine infusion increased mean arterial pressure by 12 ± 3 mmHg (P < 0.01), restoring it to normothermic values, but did not change ventilation or PET,CO2 (P > 0.05). The absence of a reduction in ventilation upon reloading the cardiopulmonary and arterial baroreceptors to pre-hyperthermic levels indicates that baroreceptor unloading with hyperthermia is unlikely to contribute to hyperthermic hyperventilation in humans. PMID:26299270

  13. In vivo transfection of manganese superoxide dismutase gene or nuclear factor κB shRNA in nodose ganglia improves aortic baroreceptor function in heart failure rats.

    PubMed

    Zhang, Dongze; Liu, Jinxu; Tu, Huiyin; Muelleman, Robert L; Cornish, Kurtis G; Li, Yu-Long

    2014-01-01

    Arterial baroreflex sensitivity is attenuated in chronic heart failure (CHF) state, which is associated with cardiac arrhythmias and sudden cardiac death in patients with CHF. Our previous study showed that CHF-induced sodium channel dysfunction in the baroreceptor neurons was involved in the blunted baroreflex sensitivity in CHF rats. Mitochondria-derived superoxide overproduction decreased expression and activation of the sodium channels in the baroreceptor neurons from CHF rats. However, the molecular mechanisms responsible for the sodium channel dysfunction in the baroreceptor neurons from CHF rats remain unknown. We tested the involvement of nuclear factor κB (NFκB) in the sodium channel dysfunction and evaluated the effects of in vivo transfection of manganese superoxide dismutase gene and NFκB shRNA on the baroreflex function in CHF rats. CHF was developed at 6 to 8 weeks after left coronary artery ligation in adult rats. Western blot and chromatin immunoprecipitation data showed that phosphorylated NFκB p65 and ability of NFκB p65 binding to the sodium channel promoter were increased in the nodose ganglia from CHF rats. In vivo transfection of adenoviral manganese superoxide dismutase gene or lentiviral NFκB p65 shRNA into the nodose ganglia partially reversed CHF-reduced sodium channel expression and cell excitability in the baroreceptor neurons and improved CHF-blunted arterial baroreflex sensitivity. Additionally, transfection of adenoviral manganese superoxide dismutase also inhibited the augmentation of phosphorylated NFκB p65 in the nodose neurons from CHF rats. The present study suggests that superoxide-NFκB signaling contributes to CHF-induced baroreceptor dysfunction and resultant impairment of baroreflex function.

  14. Effects of chronic lesions of the anteroventral third ventricle region on baroreceptor reflex function in conscious rats

    NASA Technical Reports Server (NTRS)

    Lewis, S. J.; Whalen, E. J.; Beltz, T. G.; Johnson, A. K.

    1999-01-01

    This study determined baroreceptor reflex (BR) function in conscious rats which had received sham or electrolytic lesions of the anteroventral third ventricle (AV3V) 54-56 days previously. Resting mean arterial pressure (MAP) and heart rate (HR) values of the AV3V-lesion rats were similar to those of sham-lesion rats (P>0.05 for both comparisons). The sensitivity of the BR-mediated tachycardia in AV3V-lesion was greater than in sham-lesion rats (-9. 92+/-1.00 vs. -4.54+/-0.45 bpm/mmHg, P<0.05). The sensitivity of the BR-mediated bradycardia in AV3V-lesion rats was also greater than in rats with sham lesions (-3.56+/-0.38 vs. -2.06+/-0.42 bpm/mmHg, P<0. 05). The AV3V lesions did not affect other BR parameters. These findings demonstrate that chronic lesions of the AV3V region increase the sensitivity of the baroreceptor HR reflex in conscious rats. Copyright 1999 Published by Elsevier Science B.V.

  15. Effects of chronic lesions of the anteroventral third ventricle region on baroreceptor reflex function in conscious rats

    NASA Technical Reports Server (NTRS)

    Lewis, S. J.; Whalen, E. J.; Beltz, T. G.; Johnson, A. K.

    1999-01-01

    This study determined baroreceptor reflex (BR) function in conscious rats which had received sham or electrolytic lesions of the anteroventral third ventricle (AV3V) 54-56 days previously. Resting mean arterial pressure (MAP) and heart rate (HR) values of the AV3V-lesion rats were similar to those of sham-lesion rats (P>0.05 for both comparisons). The sensitivity of the BR-mediated tachycardia in AV3V-lesion was greater than in sham-lesion rats (-9. 92+/-1.00 vs. -4.54+/-0.45 bpm/mmHg, P<0.05). The sensitivity of the BR-mediated bradycardia in AV3V-lesion rats was also greater than in rats with sham lesions (-3.56+/-0.38 vs. -2.06+/-0.42 bpm/mmHg, P<0. 05). The AV3V lesions did not affect other BR parameters. These findings demonstrate that chronic lesions of the AV3V region increase the sensitivity of the baroreceptor HR reflex in conscious rats. Copyright 1999 Published by Elsevier Science B.V.

  16. System identification of dynamic closed-loop control of total peripheral resistance by arterial and cardiopulmonary baroreceptors

    NASA Technical Reports Server (NTRS)

    Aljuri, A. N.; Bursac, N.; Marini, R.; Cohen, R. J.

    2001-01-01

    Prolonged exposure to microgravity in space flight missions (days) impairs the mechanisms responsible for defense of arterial blood pressure (ABP) and cardiac output (CO) against orthostatic stress in the post-flight period. The mechanisms responsible for the observed orthostatic intolerance are not yet completely understood. Additionally, effective counter measures to attenuate this pathophysiological response are not available. The aim of this study was to investigate the ability of our proposed system identification method to predict closed-loop dynamic changes in TPR induced by changes in mean arterial pressure (MAP) and right atrial pressure (RAP). For this purpose we designed and employed a novel experimental animal model for the examination of arterial and cardiopulmonary baroreceptors in the dynamic closed-loop control of total peripheral resistance (TPR), and applied system identification to the analysis of beat-to-beat fluctuations in the measured signals. Grant numbers: NAG5-4989. c 2001. Elsevier Science Ltd. All rights reserved.

  17. System identification of dynamic closed-loop control of total peripheral resistance by arterial and cardiopulmonary baroreceptors

    NASA Astrophysics Data System (ADS)

    Nikolai Aljuri, A.; Bursac, Nenad; Marini, Robert; Cohen, Richard J.

    2001-08-01

    Prolonged exposure to microgravity in space flight missions (days) impairs the mechanisms responsible for defense of arterial blood pressure (ABP) and cardiac output (CO) against orthostatic stress in the post-flight period. The mechanisms responsible for the observed orthostatic intolerance are not yet completely understood. Additionally, effective counter measures to attenuate this pathophysiological response are not available. The aim of this study was to investigate the ability of our proposed system identification method to predict closed-loop dynamic changes in TPR induced by changes in mean arterial pressure (MAP) and right atrial pressure (RAP). For this purpose we designed and employed a novel experimental animal model for the examination of arterial and cardiopulmonary baroreceptors in the dynamic closed-loop control of total peripheral resistance (TPR), and applied system identification to the analysis of beat-to-beat fluctuations in the measured signals.

  18. System identification of dynamic closed-loop control of total peripheral resistance by arterial and cardiopulmonary baroreceptors

    NASA Technical Reports Server (NTRS)

    Aljuri, A. N.; Bursac, N.; Marini, R.; Cohen, R. J.

    2001-01-01

    Prolonged exposure to microgravity in space flight missions (days) impairs the mechanisms responsible for defense of arterial blood pressure (ABP) and cardiac output (CO) against orthostatic stress in the post-flight period. The mechanisms responsible for the observed orthostatic intolerance are not yet completely understood. Additionally, effective counter measures to attenuate this pathophysiological response are not available. The aim of this study was to investigate the ability of our proposed system identification method to predict closed-loop dynamic changes in TPR induced by changes in mean arterial pressure (MAP) and right atrial pressure (RAP). For this purpose we designed and employed a novel experimental animal model for the examination of arterial and cardiopulmonary baroreceptors in the dynamic closed-loop control of total peripheral resistance (TPR), and applied system identification to the analysis of beat-to-beat fluctuations in the measured signals. Grant numbers: NAG5-4989. c 2001. Elsevier Science Ltd. All rights reserved.

  19. Effects of chronic carotid baroreceptor activation on arterial stiffness in severe heart failure.

    PubMed

    Gronda, Edoardo; Brambilla, GianMaria; Seravalle, Gino; Maloberti, Alessandro; Cairo, Matteo; Costantino, Giuseppe; Lovett, Eric; Vanoli, Emilio; Mancia, Giuseppe; Grassi, Guido

    2016-10-01

    Heart failure with reduced ejection fraction (HFrEF) is characterized by activation of the sympathetic nervous system and increased arterial stiffness, leading to an impaired ventricular-vascular coupling. Baroreflex activation therapy (BAT) has been shown to reduce muscle sympathetic nerve activity (MSNA) and improve clinical status of patients with HFrEF. The purpose of this investigation was to determine the effects of BAT on arterial stiffness in HFrEF. MSNA, clinical variables, and parameters of central blood pressure (BP) and arterial stiffness were collected in 18 NYHA Class III HFrEF patients, nine receiving BAT and nine continuing with optimal medical management alone. Patients were followed for 3 months, with measurements at that time compared to baseline evaluation. Baseline characteristics of the groups were well matched. At 3 months, BAT did not improve central BP and arterial stiffness despite a significant amelioration of MSNA, NYHA class, Minnesota living with heart failure questionnaire score, number of heart failure medications and six-minute walking distance. The control group exhibited no significant changes in all the measured variables. Despite significant reductions in MSNA and clinical improvement, BAT does not appear to chronically modify arterial stiffness within this HFrEF cohort. Additional study is required to determine if this result applies to the HFrEF population as a whole.

  20. Participation of the anterior hypothalamus in the baroreceptor reflex

    PubMed Central

    Hilton, S. M.; Spyer, K. M.

    1971-01-01

    1. On the basis of discrete electrical stimulation in the pre-optic region and anterior hypothalamus of anaesthetized cats, a depressor area has been defined, stimulation of which elicits a fall of arterial blood pressure of 30-50 mm Hg and a bradycardia of some 25%, caused by inhibition of sympathetic vasomotor tone and by vagal activation respectively. These are accompanied by a reduction in rate and depth of respiration. 2. The depressor area, from which this pattern of response is elicited, lies ventral and caudal to the anterior commissure, and extends caudally in the dorsal hypothalamus, dorsal to the fornix. 3. The pattern of response elicited from identified points in the depressor area was shown to be indistinguishable from that to baroreceptor afferent stimulation. 4. A lesion destroying the hypothalamic depressor area bilaterally reduced the response to baroreceptor afferent stimulation. Lesions in the medullary depressor area which spared a large part of the nucleus of the tractus solitarius also reduced, but did not abolish, the baroreceptor reflex response. The two lesions combined abolished the reflex. 5. It is concluded that the whole brain-stem depressor area, from the hypothalamus through the mid-brain to the medulla, constitutes a functional unit which integrates the response to baroreceptor afferent stimulation. PMID:5124567

  1. Altered central nervous system processing of baroreceptor input following hindlimb unloading in rats

    NASA Technical Reports Server (NTRS)

    Moffitt, J. A.; Schadt, J. C.; Hasser, E. M.

    1999-01-01

    The effect of cardiovascular deconditioning on central nervous system processing of baroreceptor afferent activity was evaluated following 14 days of hindlimb unloading (HU). Inactin-anesthetized rats were instrumented with catheters, renal sympathetic nerve electrodes, and aortic depressor nerve electrodes for measurement of mean arterial pressure, heart rate, renal sympathetic nerve activity (RSNA), and aortic depressor nerve activity (ADNA). Baroreceptor and baroreflex functions were assessed during infusion of phenylephrine and sodium nitroprusside. Central processing of baroreceptor afferent input was evaluated by linear regression relating RSNA to ADNA. The maximum baroreflex-elicited increase in RSNA was significantly reduced in HU rats (122 +/- 3.8 vs. 144 +/- 4.9% of baseline RSNA), whereas ADNA was not altered. The slope (-0.18 +/- 0.04 vs. -0.40 +/- 0.04) and y-intercept (121 +/- 3.2 vs. 146 +/- 4.3) of the linear regression relating increases in efferent RSNA to decreases in afferent ADNA during hypotension were significantly reduced in HU rats. There were no differences during increases in arterial pressure. Results demonstrate that the attenuation in baroreflex-mediated increases in RSNA following HU is due to changes in central processing of baroreceptor afferent information rather than aortic baroreceptor function.

  2. Altered central nervous system processing of baroreceptor input following hindlimb unloading in rats

    NASA Technical Reports Server (NTRS)

    Moffitt, J. A.; Schadt, J. C.; Hasser, E. M.

    1999-01-01

    The effect of cardiovascular deconditioning on central nervous system processing of baroreceptor afferent activity was evaluated following 14 days of hindlimb unloading (HU). Inactin-anesthetized rats were instrumented with catheters, renal sympathetic nerve electrodes, and aortic depressor nerve electrodes for measurement of mean arterial pressure, heart rate, renal sympathetic nerve activity (RSNA), and aortic depressor nerve activity (ADNA). Baroreceptor and baroreflex functions were assessed during infusion of phenylephrine and sodium nitroprusside. Central processing of baroreceptor afferent input was evaluated by linear regression relating RSNA to ADNA. The maximum baroreflex-elicited increase in RSNA was significantly reduced in HU rats (122 +/- 3.8 vs. 144 +/- 4.9% of baseline RSNA), whereas ADNA was not altered. The slope (-0.18 +/- 0.04 vs. -0.40 +/- 0.04) and y-intercept (121 +/- 3.2 vs. 146 +/- 4.3) of the linear regression relating increases in efferent RSNA to decreases in afferent ADNA during hypotension were significantly reduced in HU rats. There were no differences during increases in arterial pressure. Results demonstrate that the attenuation in baroreflex-mediated increases in RSNA following HU is due to changes in central processing of baroreceptor afferent information rather than aortic baroreceptor function.

  3. Baroreceptor sensitivity and diabetes mellitus.

    PubMed

    Rowaiye, Olumide Olatubosun; Jankowska, Ewa Anita; Ponikowska, Beata

    2013-01-01

    Diabetes mellitus (DM) is a disease of increasing incidence and prevalence. Arterial baroreceptors are stretch-sensitive receptors, which in a reflex manner are involved in the homeostatic control of arterial blood pressure. Diabetic subjects have depressed baroreflex sensitivity (BRS), although the exact pathomechanisms are unclear. In this review, we discuss the features, clinicaland prognostic implications of reduced BRS for diabetic patients and the potential involvement of cardiovascular autonomic neuropathy and atherosclerosis. Finally, we demonstrate evidence on interventions (e.g. pioglitazone, alpha-lipoic acid, leptin, fluvastatin, physicaltraining etc.) which could improve BRS and ameliorate cardiovascular autonomic dysfunction in diabetic patients.

  4. Sympathetic and baroreceptor reflex function in neurally mediated syncope evoked by tilt.

    PubMed Central

    Mosqueda-Garcia, R; Furlan, R; Fernandez-Violante, R; Desai, T; Snell, M; Jarai, Z; Ananthram, V; Robertson, R M; Robertson, D

    1997-01-01

    The pathophysiology of neurally mediated syncope is poorly understood. It has been widely assumed that excessive sympathetic activation in a setting of left ventricular hypovolemia stimulates ventricular afferents that trigger hypotension and bradycardia. We tested this hypothesis by determining if excessive sympathetic activation precedes development of neurally mediated syncope, and if this correlates with alterations in baroreflex function. We studied the changes in intraarterial blood pressure (BP), heart rate (HR), central venous pressure (CVP), muscle sympathetic nerve activity (MSNA), and plasma catecholamines evoked by upright tilt in recurrent neurally mediated syncope patients (SYN, 5+/-1 episodes/mo, n = 14), age- and sex-matched controls (CON, n = 23), and in healthy subjects who consistently experienced syncope during tilt (FS+, n = 20). Baroreflex responses were evaluated from changes in HR, BP, and MSNA that were obtained after infusions of phenylephrine and sodium nitroprusside. Compared to CON, patients with SYN had blunted increases in MSNA at low tilt levels, followed by a progressive decrease and ultimately complete disappearance of MSNA with syncope. SYN patients also had attenuation of norepinephrine increases and lower baroreflex slope sensitivity, both during tilt and after pharmacologic testing. FS+ subjects had the largest decrease in CVP with tilt and had significant increases in MSNA and heart rate baroreflex slopes. These data challenge the view that excessive generalized sympathetic activation is the precursor of the hemodynamic abnormality underlying recurrent neurally mediated syncope. PMID:9169504

  5. Baroreceptor output during normal and obstructed breathing and Mueller maneuvers.

    PubMed

    Fitzgerald, R S; Robotham, J L; Anand, A

    1981-05-01

    Cardiovascular control during asthma and other forms of obstructed breathing has not been extensively investigated. Previous studies in dogs have shown that obstructed breathing or an inspiratory effort against a blocked airway (Mueller maneuver) provoke large oscillations in blood pressure. During the inspiratory phase transmural systolic pressure relative to atmosphere drops initially, but transmural systolic pressure relative to intrathoracic pressure can remain unchanged or even increase. Because the carotid baroreceptors are located in the extrathoracic circulation, whereas the aortic baroreceptors are located in the intrathoracic circulation, and each responds to local transmural arterial pressure, simultaneous baroreceptor output from these two areas was measured in the anesthetized cat during normal and obstructed breathing and during Mueller maneuvers. Both whole-nerve and single-fiber preparations showed a significantly decreased output from the carotid baroreceptors during obstructed inspiratory efforts, whereas aortic baroreceptor output decreased significantly less or not at all. Transmural systolic pressure decreased significantly less in the aorta than in the carotid regions. Further, the aortic baroreceptors were more sensitive to changes in pulse pressure than were the carotid baroreceptors. These results suggest a mechanism for stabilizing the cardiac responses to precipitous falls in blood pressure that occur in obstructed breathing.

  6. The Ion Channel ASIC2 is Required for Baroreceptor and Autonomic Control of the Circulation

    PubMed Central

    Lu, Yongjun; Ma, Xiuying; Sabharwal, Rasna; Snitsarev, Vladislav; Morgan, Donald; Rahmouni, Kamal; Drummond, Heather A.; Whiteis, Carol A.; Costa, Vivian; Price, Margaret; Benson, Christopher; Welsh, Michael J.; Chapleau, Mark W.; Abboud, François M.

    2009-01-01

    SUMMARY Arterial baroreceptors provide a neural sensory input that reflexly regulates the autonomic drive of the circulation. Our goal was to test the hypothesis that a member of the acid sensing ion channel (ASIC) subfamily of the DEG/ENaC superfamily is an important determinant of the arterial baroreceptor reflex. We found that aortic baroreceptor neurons in the nodose ganglia and their terminals express ASIC2. Conscious ASIC2 null mice developed hypertension, had exaggerated sympathetic and depressed parasympathetic control of the circulation, and a decreased gain of the baroreflex, all indicative of an impaired baroreceptor reflex. Multiple measures of baroreceptor activity each suggests that mechanosensitivity is diminished in ASIC2- null mice. The results define ASIC2 as an important determinant of autonomic circulatory control and of baroreceptor sensitivity. The genetic disruption of ASIC2 recapitulates the pathological dysautonomia seen in heart failure and hypertension and defines a molecular defect that may be relevant to its development. PMID:20064394

  7. Influence of low and high pressure baroreceptors on plasma renin activity in humans

    NASA Technical Reports Server (NTRS)

    Mark, A. L.; Abboud, F. M.; Fitz, A. E.

    1977-01-01

    The effects of low and high pressure baroreceptors on plasma renin activity (immunoassay) were evaluated using graded lower body suction (LBS) in six healthy men. LBS at -10 and -20 mmHg for 10 min decreased central venous pressure without changing arterial pressure and thereby presumably reduced low but not high pressure baroreceptor inhibition of renin release. LBS at these levels produced forearm vasoconstriction, but did not increase renin. LBS at -40 mmHG decreased central venous and arterial pulse pressure and thus reduced both low and high pressure baroreceptor inhibition. LBS at this level produced forearm vasoconstriction and tachycardia and increased renin. In summary, reduction in low pressure baroreceptor inhibition in humans did not increase renin in the presence of physiological tonic inhibition from high pressure baroreceptors. Increases in renin did not occur until there was combined reduction of high and low pressure baroreceptor inhibition on plasma renin activity.

  8. [Physiology and methods for studying the baroreceptor reflex].

    PubMed

    Hilz, M J; Stemper, B; Neundörfer, B

    2000-01-01

    The baroreflex is of major importance for the moment-to-moment maintenance of arterial pressure particularly during orthostatic stress. Blood pressure increase stimulates the receptors e.g. in the carotid sinuses and the aortic arch, and rapidly increases the receptor discharge rate. Blood pressure decrease induces arrest of impulse transmission to the nucleus of the solitary tract. The impulses are modulated by the nucleus ambiguous, the rostral ventrolateral medulla, the dorsal nucleus of the vagus nerve, parabrachial and paraventricular nuclei and other central structures. Blood pressure increase induces an increase of cardiovagal activity resulting in cardiodeceleration and a decrease of sympathetic peripheral vasoconstrictor outflow. The receptor firing rates show adaptation and resetting to longer lasting blood pressure changes, hysteresis, i.e. firing rates that are higher with rapid blood pressure increase than during the return to baseline pressure. The receptors interact with respiration, chemoreceptor stimulation, central stimuli, exercise and sleep, etc. Baroreceptor function and interaction e.g. with chemoreceptors is compromised in diseases such as diabetic autonomic neuropathy. Guillain-Barré syndrome, arterial hypertension, heart failure and probably in most stroke patients. Fatal complications may result from baroreceptor malfunction. Subtle analysis of the baroreflex is therefore crucial for a refined pathophysiological understanding of these diseases. Pharmacological testing and "neck chamber" negative pressure stimulation of the receptors are as useful as the non-invasive computerized analysis of the interaction of spontaneous blood pressure and heart rate fluctuations.

  9. Caudal ventrolateral medulla mediates baroreceptor afferent inputs to subfornical organ angiotensin II responsive neurons.

    PubMed

    Ciriello, John

    2013-01-23

    Although anatomical data indicates that the caudal ventrolateral medulla (CVLM) projects directly to the subfornical organ (SFO), little is known about the afferent information relayed through the CVLM to SFO. Experiments were done in the anesthetized rat to investigate whether CVLM neurons mediate baroreceptor afferent information to SFO and whether this afferent information alters the response of SFO neurons to systemic injections of angiotensin II (ANG II). Extracellular single unit recordings were made from 78 spontaneously discharging single units in SFO. Of these, 32 (41%) responded to microinjection of L-glutamate (L-Glu; 0.25M; 10nl) into CVLM (27/32 were inhibited and 5/32 were excited). All 32 units also were excited by systemic injections of ANG II (250ng/0.1ml, ia). However, only those units inhibited by CVLM (n=27) were found to be inhibited by the reflex activation of baroreceptors following systemic injections of phenylephrine (2μg/kg, iv). Activation of CVLM or arterial baroreceptors in conjunction with ANG II resulted in an attenuation of the SFO unit's response to ANG II. Finally, microinjections (100nl) of the synaptic blocker CoCl(2) or the non-specific glutamate receptor antagonist kynurenic acid into CVLM attenuated (10/13 units tested) the SFO neuron's response to activation of baroreceptors, but not the unit's response evoked by systemic ANG II. Taken together, these data suggest that baroreceptor afferent information relayed through CVLM functions to modulate of the activity of neurons within SFO to extracellular signals of body fluid balance. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Neuronal expression of nuclear transcription factor MafG in the rat medulla oblongata after baroreceptor stimulation.

    PubMed

    Kumaki, Iku; Yang, Dawei; Koibuchi, Noriyuki; Takayama, Kiyoshige

    2006-03-06

    The medulla oblongata is the site of central baroreceptive neurons in mammals. These neurons express specific basic-leucine zipper transcription factors (bZIP) after baroreceptor stimulation. Previously we showed that activation of baroreceptors induced expression of nuclear transcription factors c-Fos and FosB in central baroreceptive neurons. Here we studied the effects of baroreceptor stimulation on induction of MafG, a member of small Maf protein family that functions as dimeric partners for various bZIP transcription factors by forming transcription-regulating complexes, in the rat medulla oblongata. To determine whether gene expression of MafG is induced by stimulation of arterial baroreceptors, we examined the expression of its mRNA by semi-quantitative reverse transcription-PCR method and its gene product by immunohistochemistry. We found that the number of MafG transcripts increased significantly in the medulla oblongata after baroreceptor stimulation. MafG-immunoreactive neurons were distributed in the nucleus tractus solitarii, the dorsal motor nucleus of the vagus nerve, the ambiguous nucleus and the ventrolateral medulla. The numbers of MafG-immunoreactive neurons in these nuclei were significantly greater in test rats than in saline-injected control rats. We also found approximately 20% of MafG-immunoreactive neurons coexpress FosB after baroreceptor stimulation. Our results suggest that MafG cooperates with FosB to play critical roles as an immediate early gene in the signal transduction of cardiovascular regulation mediated by baroreceptive signals in the medulla oblongata.

  11. Respiratory muscle training improves hemodynamics, autonomic function, baroreceptor sensitivity, and respiratory mechanics in rats with heart failure.

    PubMed

    Jaenisch, Rodrigo B; Hentschke, Vítor S; Quagliotto, Edson; Cavinato, Paulo R; Schmeing, Letiane A; Xavier, Léder L; Dal Lago, Pedro

    2011-12-01

    Respiratory muscle training (RMT) improves functional capacity in chronic heart-failure (HF) patients, but the basis for this improvement remains unclear. We evaluate the effects of RMT on the hemodynamic and autonomic function, arterial baroreflex sensitivity (BRS), and respiratory mechanics in rats with HF. Rats were assigned to one of four groups: sedentary sham (n = 8), trained sham (n = 8), sedentary HF (n = 8), or trained HF (n = 8). Trained animals underwent a RMT protocol (30 min/day, 5 day/wk, 6 wk of breathing through a resistor), whereas sedentary animals did not. In HF rats, RMT had significant effects on several parameters. It reduced left ventricular (LV) end-diastolic pressure (P < 0.01), increased LV systolic pressure (P < 0.01), and reduced right ventricular hypertrophy (P < 0.01) and pulmonary (P < 0.001) and hepatic (P < 0.001) congestion. It also decreased resting heart rate (HR; P < 0.05), indicating a decrease in the sympathetic and an increase in the vagal modulation of HR. There was also an increase in baroreflex gain (P < 0.05). The respiratory system resistance was reduced (P < 0.001), which was associated with the reduction in tissue resistance after RMT (P < 0.01). The respiratory system and tissue elastance (Est) were also reduced by RMT (P < 0.01 and P < 0.05, respectively). Additionally, the quasistatic Est was reduced after RMT (P < 0.01). These findings show that a 6-wk RMT protocol in HF rats promotes an improvement in hemodynamic function, sympathetic and vagal heart modulation, arterial BRS, and respiratory mechanics, all of which are benefits associated with improvements in cardiopulmonary interaction.

  12. Baroreceptor reflex failure: Review of the literature and the potential impact on patients with head and neck cancer.

    PubMed

    Shah-Becker, Shivani; Pennock, Michael; Sinoway, Lawrence; Goldenberg, David; Goyal, Neerav

    2017-10-01

    Baroreceptor dysfunction and reflex failure may occur after surgery affecting the carotid artery. The implications for patients undergoing treatment for head and neck cancer are not well described. A literature search of PubMed was performed between March 2016 and May 2016. Search terms used individually and in combination included: "baroreflex failure," "carotid sinus sensitivity," "carotid endarterectomy," "carotid body tumor," and "head and neck cancer." Bibliographies of included articles were also reviewed for additional pertinent articles. There is evidence of baroreceptor failure in certain patients after interventions associated with the carotid artery, including carotid endarterectomy and carotid body tumor excision. Few studies have been performed investigating the potential effect of head and neck surgery treatment, including surgery and/or radiation, on baroreflex function. Head and neck cancer treatment has the potential to cause baroreflex failure, and this is likely an underrecognized and underdiagnosed condition. © 2017 Wiley Periodicals, Inc.

  13. Mitochondria-derived superoxide and voltage-gated sodium channels in baroreceptor neurons from chronic heart-failure rats

    PubMed Central

    Tu, Huiyin; Liu, Jinxu; Zhu, Zhen; Zhang, Libin; Pipinos, Iraklis I.

    2012-01-01

    Our previous study has shown that chronic heart failure (CHF) reduces expression and activation of voltage-gated sodium (Nav) channels in baroreceptor neurons, which are involved in the blunted baroreceptor neuron excitability and contribute to the impairment of baroreflex in the CHF state. The present study examined the role of mitochondria-derived superoxide in the reduced Nav channel function in coronary artery ligation-induced CHF rats. CHF decreased the protein expression and activity of mitochondrial complex enzymes and manganese SOD (MnSOD) and elevated the mitochondria-derived superoxide level in the nodose neurons compared with those in sham nodose neurons. Adenoviral MnSOD (Ad.MnSOD) gene transfection (50 multiplicity of infection) into the nodose neurons normalized the MnSOD expression and reduced the elevation of mitochondrial superoxide in the nodose neurons from CHF rats. Ad.MnSOD also partially reversed the reduced protein expression and current density of the Nav channels and the suppressed cell excitability (the number of action potential and the current threshold for inducing action potential) in aortic baroreceptor neurons from CHF rats. Data from the present study indicate that mitochondrial dysfunction, including decreased protein expression and activity of mitochondrial complex enzymes and MnSOD and elevated mitochondria-derived superoxide, contributes to the reduced Nav channel activation and cell excitability in the aortic baroreceptor neurons in CHF rats. PMID:22072507

  14. Carotid baroreceptor influence on forearm vascular resistance during low level lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Thompson, Cynthia A.; Ludwig, David A.; Convertino, Victor A.

    1991-01-01

    The degree of forearm vasoconstriction induced by low levels of lower body negative pressure (LBNP) provides a measure of the responsiveness of the cardiopulmonary baroreflex. The validity of this measurement is based on the assumption that this vasoconstriction response is not influenced by unloading of carotid baroreceptors. To test the hypothesis that arterial baroreceptor unloading does not alter the degree of forearm vascular resistance during low levels of LBNP, 12 subjects were exposed to -15 and -20 mm Hg LBNP with and without additional artificial (+ 10 mm Hg neck pressure) unloading of the carotid baroreceptors. There was no measurable influence of carotid unloading on forearm vascular resistance at either level of LBNP. It is concluded that forearm vascular resistance measured during cardiopulmonary baroreceptor unloading is unaffected by carotid baroreceptor unloading within the magnitude encountered during low levels of LBNP.

  15. Effects of baroreceptor stimulation on performance of the Sternberg short-term memory task: a cardiac cycle time study.

    PubMed

    Quelhas Martins, Amadeu; McIntyre, David; Ring, Christopher

    2014-12-01

    Activation of arterial baroreceptors can affect cortical activity. Cardiac cycle time studies have established that natural variations in baroreceptor activation are associated with changes in basic sensorimotor function whereas few have investigated more complex cognitive function. Aiming to improve our understanding of this phenomenon, this study examined performance on the Sternberg memory task as a function of the phase of the cardiac cycle. In each trial, participants were shown either two or six digits followed by a probe digit that either had or had not been presented previously and were required to press one of two response buttons to indicate a match and mismatch, respectively. Response latency per additional digit was greater for stimuli presented late compared to early in the cardiac cycle whereas the zero intercept was greatest at the start of the cardiac cycle and reduced as the cycle progressed. These findings provide evidence that natural baroreceptor stimulation can affect complex cognitive processes, such as serial-comparison in short-term memory, as well as basic sensorimotor processes. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Responses to circulatory pressures, and conduction velocity, of pulmocutaneous baroreceptors in Bufo marinus.

    PubMed Central

    Van Vliet, B N; West, N H

    1987-01-01

    1. Baroreceptor activity was recorded within the recurrent laryngeal branch of the toad vagus in forty-four preparations. The receptive fields of the receptors were located in the pulmocutaneous artery (p.c.a.), generally within 5 mm of its separation from the truncus. However, the most easily recorded afferents in this nerve were mechanoreceptors which responded to punctate stimulation of the lip of the glottis. 2. The conduction velocities of p.c.a. baroreceptor and mechanoreceptive glottal afferents recorded in the recurrent laryngeal nerve ranged from 0.3-0.7 (0.5 +/- 0.1) m s-1 and 2.2-14.0 (6.8 +/- 0.8) m s-1 respectively, which suggests that baroreceptor afferent fibres are non-myelinated and that glottal afferent fibres are myelinated. 3. The p.c.a. baroreceptor discharge was largely confined to a period of systole in which systemic and p.c.a. arterial pressure profiles were identical. The maximum discharge frequency, number of spikes per cycle, and the duration of discharge increased, and the discharge latency decreased, as p.c.a. pressures were elevated. The latency of the discharge was pronounced at low p.c.a. pressures, and could be partially accounted for by the conduction time of the baroreceptor afferents to the electrodes (up to 100 ms). 4. Carotid and aortic arterial baroreceptor and pharyngeal afferents were recorded in two pharyngeal branches of the vagus nerve which were closely associated with the carotid and aortic arterial arches. 5. It is suggested that baroreceptor populations with their receptive fields in the third- (carotid) and sixth- (p.c.a. or pulmonary) arch arteries should be considered homologous in anurans and mammals, but that those of the fourth- (aorta) arch artery should not, since the vagal branches in which their afferents are carried do not appear to be equivalent in anurans and mammals. Images Fig. 8 PMID:3116216

  17. CHBPR Proton Magnetic Resonance Spectroscopy Detection of Neurotransmitters in Dorsomedial Medulla Correlate with Spontaneous Baroreceptor Reflex Function

    PubMed Central

    Garcia-Espinosa, Maria A.; Shaltout, Hossam A.; Olson, John; Westwood, Brian M.; Robbins, Mike E.; Link, Kerry; Diz, Debra I.

    2010-01-01

    Control of heart rate variability (HRV) via modulation of sympathovagal balance is a key function of nucleus tractus solitarii (nTS) and dorsal motor nucleus of the vagus localized in the dorsomedial medulla oblongata. Normal blood pressure regulation involves precise balance of glutamate-glutamine-GABA (Glu-Gln-GABA) transmitter systems, and angiotensin (Ang) II modulates these transmitters to produce tonic suppression of reflex function. It is not known, however, whether other brain transmitters/metabolites are indicators of baroreflex function. This study establishes the concept that comprehensive baseline transmitter/metabolite profiles obtained using in vivo 1H Magnetic Resonance Spectroscopy (1H MRS) in rats with well characterized differences in resting blood pressure and baroreflex function can be used as indices of autonomic balance or baroreflex sensitivity. Glu concentration in dorsal medulla is significantly higher in ASrAogen rats compared to either SD and (mRen2)27. Glu levels and the ratio of Glu/Gln correlated positively with indices of higher vagal tone consistent with the importance of these neurotransmitters in baroreflex function. Interestingly, the levels of choline containing metabolites showed a significant positive correlation with spontaneous baroreflex sensitivity and a negative correlation with sympathetic tone. Thus, we demonstrate the concept that non-invasive assessment of neurochemical biomarkers may be used as an index of baroreflex sensitivity. PMID:20065146

  18. Effect of osmotic stimuli on the carotid baroreceptor and chemoreceptor discharges in cats.

    PubMed

    Trzebski, A; Chruścielewski, L; Majcherczyk, S

    1978-01-01

    In 15 cats under chloralose-urethan anaesthesia carotid sinus area was arterially isolated and perfused with artificially pulsatile pressures. Solutions of NaCl, of various osmolality, mannitol, glucose and bicarbonate were locally perfused through the isolated carotid area and the single baroreceptor and chemoreceptor fibre activity was recorded with standard technique. An increase in the osmolality of the perfused fluid evoked an increase of the single baroreceptor discharge. Each pulse pressure produced more spikes of higher frequency in big A type baroreceptor fibres. Clear effects were observed during perfusion of 300 mM NCl solutions. Solutions of higher osmolility transformed rhythmical pulse pressure discharge into continuous baroreceptor firing. The excitatory effects of hyperosmolar solutions were reversible after switching to the perfusion fluids of normal osmolality. An increased activity was also observed in the single carotid chemoreceptor fibres. It is concluded that both baro- and chemoreceptors are sensitive to osmotic stimulation.

  19. Phase dependencies of the human baroreceptor reflex

    NASA Technical Reports Server (NTRS)

    Seidel, H.; Herzel, H.; Eckberg, D. L.

    1997-01-01

    We studied the influence of respiratory and cardiac phase on responses of the cardiac pacemaker to brief (0.35-s) increases of carotid baroreceptor afferent traffic provoked by neck suction in seven healthy young adult subjects. Cardiac responses to neck suction were measured indirectly from electrocardiographic changes of heart period. Our results show that it is possible to separate the influences of respiratory and cardiac phases at the onset of a neck suction impulse by a product of two factors: one depending only on the respiratory phase and one depending only on the cardiac phase. This result is consistent with the hypothesis that efferent vagal activity is a function of afferent baroreceptor activity, whereas respiratory neurons modulate that medullary throughput independent of the cardiac phase. Furthermore, we have shown that stimulus broadening and stimulus cropping influence the outcome of neck suction experiments in a way that makes it virtually impossible to obtain information on the phase dependency of the cardiac pacemaker's sensitivity to vagal stimulation without accurate knowledge of the functional shape of stimulus broadening.

  20. Phase dependencies of the human baroreceptor reflex

    NASA Technical Reports Server (NTRS)

    Seidel, H.; Herzel, H.; Eckberg, D. L.

    1997-01-01

    We studied the influence of respiratory and cardiac phase on responses of the cardiac pacemaker to brief (0.35-s) increases of carotid baroreceptor afferent traffic provoked by neck suction in seven healthy young adult subjects. Cardiac responses to neck suction were measured indirectly from electrocardiographic changes of heart period. Our results show that it is possible to separate the influences of respiratory and cardiac phases at the onset of a neck suction impulse by a product of two factors: one depending only on the respiratory phase and one depending only on the cardiac phase. This result is consistent with the hypothesis that efferent vagal activity is a function of afferent baroreceptor activity, whereas respiratory neurons modulate that medullary throughput independent of the cardiac phase. Furthermore, we have shown that stimulus broadening and stimulus cropping influence the outcome of neck suction experiments in a way that makes it virtually impossible to obtain information on the phase dependency of the cardiac pacemaker's sensitivity to vagal stimulation without accurate knowledge of the functional shape of stimulus broadening.

  1. Modeling the Carotid Sinus Baroreceptor

    PubMed Central

    Srinivasan, Ramachandra; Nudelman, Harvey B.

    1972-01-01

    A mathematical model that describes the relationship between sinus pressure and nerve discharge frequency of the carotid sinus baroreceptor is presented. It is partly based upon the single-fiber data obtained by Clarke from the sinus nerve of a dog. The model takes into account what is currently known about the physiology of the baroreceptor. It consists of two nonlinear ordinary differential equations and eight free parameters. With one set of values for these eight parameters, the model reproduces well the experimental results reported by Clarke for positive ramp pressure inputs. Only three parameters needed to be adjusted in order to fit the dynamic data. The remaining five were obtained from static and steady-state data. PMID:5056961

  2. Experimenting With Baroreceptor Reflexes

    NASA Technical Reports Server (NTRS)

    Eckberg, Dwain L.; Goble, Ross L.

    1988-01-01

    Carotid arteries stimulated by pressure or suction on neck. Baro-Cuff is silicone-rubber chamber that fits on front of subject's neck. Electronic system, stepping motor, bellows, and umbilical tube furnish controlled pressure to chamber. Pressure sensor provides feedback to microprocessor in electronic system. Developed to study blood-pressure-reflex responses of astronauts in outer space. Useful for terrestrial studies of patients with congestive heart failure, chronic diabetes mellitus, and other conditions in which blood-pressure-reflex controls behave abnormally.

  3. Carotid baroreceptor-muscle sympathetic relation in humans.

    PubMed

    Rea, R F; Eckberg, D L

    1987-12-01

    The purpose of this study was to define the relation between carotid distending pressure and muscle sympathetic activity in humans. Carotid baroreceptors of nine healthy subjects were compressed or stretched for 5 s with graded neck pressure or suction (+40 to -65 mmHg), and muscle sympathetic nerve activity was recorded. The results delineate several features of human baroreflex function. First, the carotid-muscle sympathetic relation is well described by an inverse sigmoid function. Second, a linear relation exists between carotid distending pressure and sympathetic outflow over a range of approximately 25 mmHg. Third, sympathetic responses to changes of carotid pressures are asymmetric; increases of sympathetic activity during carotid compression are much greater than reductions of sympathetic activity during carotid stretch. Fourth, at rest, normal subjects operate near the threshold level for sympathetic excitation. Thus the carotid-muscle sympathetic baroreflex is poised to oppose reductions more effectively than elevations of arterial pressure, and the range of pressures over which the reflex is active is wider than thought hitherto.

  4. Short-duration spaceflight impairs human carotid baroreceptor-cardiac reflex responses

    NASA Technical Reports Server (NTRS)

    Fritsch, Janice M.; Charles, John B.; Bennett, Barbara S.; Jones, Michele M.; Eckberg, Dwain L.

    1992-01-01

    The effect of a spaceflight on the vagally mediated baroreceptor-cardiac reflex responses of humans were investigated by measuring the responses (provoked by neck pressure changes) in supine position and the heart rate and blood pressure in the supine and standing positions in 16 astronauts before and after 4- to 5-day long Space Shuttle missions. The results showed that exposures to spaceflight resulted in reduced baseline levels of the vagal-cardiac outflow and the vagally mediated responses to changes of the arterial baroreceptor input and that these changes contribute to postflight reductions of astronauts' ability to maintain standing arterial pressures.

  5. Cardiopulmonary baroreceptor control of muscle sympathetic nerve activity in heat-stressed humans

    NASA Technical Reports Server (NTRS)

    Crandall, C. G.; Etzel, R. A.; Farr, D. B.

    1999-01-01

    Whole body heating decreases central venous pressure (CVP) while increasing muscle sympathetic nerve activity (MSNA). In normothermia, similar decreases in CVP elevate MSNA, presumably via cardiopulmonary baroreceptor unloading. The purpose of this project was to identify whether increases in MSNA during whole body heating could be attributed to cardiopulmonary baroreceptor unloading coincident with the thermal challenge. Seven subjects were exposed to whole body heating while sublingual temperature, skin blood flow, heart rate, arterial blood pressure, and MSNA were monitored. During the heat stress, 15 ml/kg warmed saline was infused intravenously over 7-10 min to increase CVP and load the cardiopulmonary baroreceptors. We reported previously that this amount of saline was sufficient to return CVP to pre-heat stress levels. Whole body heating increased MSNA from 25 +/- 3 to 39 +/- 3 bursts/min (P < 0. 05). Central blood volume expansion via rapid saline infusion did not significantly decrease MSNA (44 +/- 4 bursts/min, P > 0.05 relative to heat stress period) and did not alter mean arterial blood pressure (MAP) or pulse pressure. To identify whether arterial baroreceptor loading decreases MSNA during heat stress, in a separate protocol MAP was elevated via steady-state infusion of phenylephrine during whole body heating. Increasing MAP from 82 +/- 3 to 93 +/- 4 mmHg (P < 0.05) caused MSNA to decrease from 36 +/- 3 to 15 +/- 4 bursts/min (P < 0.05). These data suggest that cardiopulmonary baroreceptor unloading during passive heating is not the primary mechanism resulting in elevations in MSNA. Moreover, arterial baroreceptors remain capable of modulating MSNA during heat stress.

  6. Cardiopulmonary baroreceptor control of muscle sympathetic nerve activity in heat-stressed humans

    NASA Technical Reports Server (NTRS)

    Crandall, C. G.; Etzel, R. A.; Farr, D. B.

    1999-01-01

    Whole body heating decreases central venous pressure (CVP) while increasing muscle sympathetic nerve activity (MSNA). In normothermia, similar decreases in CVP elevate MSNA, presumably via cardiopulmonary baroreceptor unloading. The purpose of this project was to identify whether increases in MSNA during whole body heating could be attributed to cardiopulmonary baroreceptor unloading coincident with the thermal challenge. Seven subjects were exposed to whole body heating while sublingual temperature, skin blood flow, heart rate, arterial blood pressure, and MSNA were monitored. During the heat stress, 15 ml/kg warmed saline was infused intravenously over 7-10 min to increase CVP and load the cardiopulmonary baroreceptors. We reported previously that this amount of saline was sufficient to return CVP to pre-heat stress levels. Whole body heating increased MSNA from 25 +/- 3 to 39 +/- 3 bursts/min (P < 0. 05). Central blood volume expansion via rapid saline infusion did not significantly decrease MSNA (44 +/- 4 bursts/min, P > 0.05 relative to heat stress period) and did not alter mean arterial blood pressure (MAP) or pulse pressure. To identify whether arterial baroreceptor loading decreases MSNA during heat stress, in a separate protocol MAP was elevated via steady-state infusion of phenylephrine during whole body heating. Increasing MAP from 82 +/- 3 to 93 +/- 4 mmHg (P < 0.05) caused MSNA to decrease from 36 +/- 3 to 15 +/- 4 bursts/min (P < 0.05). These data suggest that cardiopulmonary baroreceptor unloading during passive heating is not the primary mechanism resulting in elevations in MSNA. Moreover, arterial baroreceptors remain capable of modulating MSNA during heat stress.

  7. Tonic blood pressure modulates the relationship between baroreceptor cardiac reflex sensitivity and cognitive performance.

    PubMed

    Del Paso, Gustavo A Reyes; González, M Isabel; Hernández, José Antonio; Duschek, Stefan; Gutiérrez, Nicolás

    2009-09-01

    This study explored the effects of tonic blood pressure on the association between baroreceptor cardiac reflex sensitivity and cognitive performance. Sixty female participants completed a mental arithmetic task. Baroreceptor reflex sensitivity was assessed using sequence analysis. An interaction was found, indicating that the relationship between baroreceptor reflex sensitivity and cognitive performance is modulated by blood pressure levels. Reflex sensitivity was inversely associated to performance indices in the subgroup of participants with systolic blood pressure above the mean, whereas the association was positive in participants with systolic values below the mean. These results are in accordance with the findings in the field of pain perception and suggest that tonic blood pressure modulates the inhibitory effects of baroreceptor stimulation on high central nervous functions.

  8. Measuring How Elastic Arteries Function.

    ERIC Educational Resources Information Center

    DeMont, M. Edwin; MacGillivray, Patrick S.; Davison, Ian G.; McConnell, Colin J.

    1997-01-01

    Describes a procedure used to measure force and pressure in elastic arteries. Discusses the physics of the procedure and recommends the use of bovine arteries. Explains the preparation of the arteries for the procedure. (DDR)

  9. Measuring How Elastic Arteries Function.

    ERIC Educational Resources Information Center

    DeMont, M. Edwin; MacGillivray, Patrick S.; Davison, Ian G.; McConnell, Colin J.

    1997-01-01

    Describes a procedure used to measure force and pressure in elastic arteries. Discusses the physics of the procedure and recommends the use of bovine arteries. Explains the preparation of the arteries for the procedure. (DDR)

  10. Familial dysautonomia (Riley-Day syndrome): when baroreceptor feedback fails.

    PubMed

    Norcliffe-Kaufmann, Lucy; Kaufmann, Horacio

    2012-12-24

    Familial dysautonomia (FD) is a rare hereditary disorder caused by mutations within the gene that encodes for I-κ-B kinase complex associated protein (IKAP). A deficiency of IKAP affects the development of primary sensory neurons including those carrying baroreflex afferent volleys, a feature that explains their characteristic sensory loss and labile blood pressure. This review describes the history, the genotype of FD and the unusual cardiovascular autonomic phenotype of these patients. We outline the main consequences of a failure to receive information from arterial baroreceptors, including the characteristic "autonomic storms" and severe end-organ target damage. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Enhanced baroreceptor control of the cardiovascular system by polyunsaturated Fatty acids in heart failure patients.

    PubMed

    Radaelli, Alberto; Cazzaniga, Maria; Viola, Andrea; Balestri, Giulia; Janetti, Maria Bianchi; Signorini, Maria G; Castiglioni, Paolo; Azzellino, Arianna; Mancia, Giuseppe; Ferrari, Alberto U

    2006-10-17

    The intention of this study was to test the hypothesis that, in heart failure patients, dietary supplementation of polyunsaturated fatty acids (PUFA) enhances arterial baroreceptor control of the cardiovascular system. Administration of PUFA reduces the risk of life-threatening arrhythmias in patients surviving myocardial infarction. This might result from potentiation of arterial baroreflexes, but whether or not PUFA enhance baroreflex function has never been studied in humans. Patients with post-myocardial infarction left ventricular dysfunction underwent beat-to-beat blood pressure (BP) (Finapres, Ohmeda Inc., Englewood, Colorado) and R-R interval (electrocardiogram) recording; baroreceptor reflexes were assessed from the bradycardic and depressor responses to graded neck suction (NS) as well as by computation of the alpha "spontaneous" baroreflex sensitivity index. Assessments were repeated after prolonged treatment with PUFA (2 g/die, n = 15) or placebo (n = 10). Baseline BP and R-R interval were unaffected by PUFA. Both reflex depressor and bradycardic responses to NS increased after PUFA (respectively from -0.09 +/- 0.01 to -0.16 +/- 0.01 mm Hg x mm Hg(-1), p < 0.01, and from 1.25 +/- 0.9 to 1.76 +/- 1.1 ms x mm Hg(-1), p < 0.04) but not after placebo. The spontaneous baroreflex sensitivity increased in the PUFA (from 8.99 +/- 1.4 to 12.2 +/- 1.2 ms x mm Hg(-1), p < 0.02) but not in the placebo group. Polyunsaturated fatty acids (but not placebo) treatment also significantly increased R-R interval total variance and low-frequency and high-frequency spectral powers. Dietary PUFA supplementation markedly potentiates baroreflex function and enhances heart rate variability in patients with stable congestive heart failure.

  12. Contribution of potassium channels to the discharge properties of rat aortic baroreceptor sensory endings.

    PubMed

    Reynolds, P J; Yang, M; Andresen, M C

    1994-11-28

    The expression of several types of membrane potassium channel at the cell body and central synaptic terminal of the rat aortic arch baroreceptor has been reported by others. It is not known if any of the same channels function at the peripheral sensory terminal of these afferent nerves. Our study examined the effect of three potassium channel blocking agents on the pressure-evoked discharge of such baroreceptors. Thirty-one single unit, regularly discharging baroreceptors were studied using an in vitro aortic arch-aortic nerve preparation. Discharge thresholds and suprathreshold pressure sensitivities were derived from responses of receptors to slowly rising ramps of pressure applied to the aortic arch. Vessel diameter was recorded along with receptor discharge to assess any drug-induced changes in vascular smooth muscle. The blocking agents tested have a range of specificities for classes of potassium channels: tetraethylammonium (TEA), 4-aminopyridine (4-AP) and charybdotoxin. TEA depressed the pressure sensitivity of all baroreceptors tested (n = 3) in a dose-dependent manner. Baroreceptor responses to 4-AP were complex (n = 22) and varied widely across individuals. Three were unaffected by 5 mM 4-AP. Most baroreceptors were generally depressed by 4-AP. Some of the 4-AP effects appeared to be related to actions at vascular smooth muscle. None of the baroreceptors tested (n = 6) was affected by charybdotoxin. The results of selective potassium channel blockade are generally consistent with what would be expected from a sustained depolarization of baroreceptor endings such as has been reported with raising extracellular potassium and probably includes effects of inactivation of other voltage-dependent channels.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. From supine to standing: in vivo segregation of myogenic and baroreceptor vasoconstriction in humans.

    PubMed

    Estañol, Bruno; Rivera, Ana Leonor; Martínez Memije, Raúl; Fossion, Ruben; Gómez, Fermín; Bernal, Katherine; Murúa Beltrán, Sofía; Delgado-García, Guillermo; Frank, Alejandro

    2016-12-01

    Myogenic vascular response is a form of systemic and regional vasoconstriction produced increasing the intra-arterial pressure by gravity. Here, the vasoconstriction due to the myogenic response, induced by the gravitational action in a dependent limb, is separated from that caused by the baroreceptor reflex. Regional changes of skin blood flow (SBF), total blood volume of the finger (TBVF), pulse pressure (PP), heart rate (HR), systolic, and diastolic blood pressure (BP) were analyzed in 10 healthy young subjects in supine and upright positions. By lowering the arm in supine position, SBF decreased compared to its basal measurement, PR increased, and PP contracted, indicating arterial vasoconstriction that rise BP TBVF increased, demonstrating an increment in venous volume. HR did not change, reflecting no action of the baroreceptor reflex. In upright position with lowered arm, there was an additional increase in BP variables, demonstrating vasoconstriction. Moreover, BP and HR showed oscillations at 0.1 Hz reflecting the entrance of the baroreceptor reflex. The action of gravity in a dependent limb in supine position induces a regional vasoconstriction and an increase of BP due to activation of the myogenic response, while the baroreceptor reflex or other neural factors do not appear to operate. In the upright position with the arm dependent, there is a further increase in regional vasoconstriction and BP with reciprocal changes in HR, indicating the entrance of the baroreceptor superimposed to the myogenic response. This study demonstrates that the myogenic and baroreceptor vasoconstriction can be separated in vivo. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  14. Arterial endothelial function measurement method and apparatus

    DOEpatents

    Maltz, Jonathan S; Budinger, Thomas F

    2014-03-04

    A "relaxoscope" (100) detects the degree of arterial endothelial function. Impairment of arterial endothelial function is an early event in atherosclerosis and correlates with the major risk factors for cardiovascular disease. An artery (115), such as the brachial artery (BA) is measured for diameter before and after several minutes of either vasoconstriction or vasorelaxation. The change in arterial diameter is a measure of flow-mediated vasomodification (FMVM). The relaxoscope induces an artificial pulse (128) at a superficial radial artery (115) via a linear actuator (120). An ultrasonic Doppler stethoscope (130) detects this pulse 10-20 cm proximal to the point of pulse induction (125). The delay between pulse application and detection provides the pulse transit time (PTT). By measuring PTT before (160) and after arterial diameter change (170), FMVM may be measured based on the changes in PTT caused by changes in vessel caliber, smooth muscle tone and wall thickness.

  15. [Long time regulation of arterial blood pressure: facts and hypothesis].

    PubMed

    Tsyrlin, V A

    2013-01-01

    The date about long time increase of blood pressure in conditions of excessive salt intake, constriction of renal artery in animals with initial low baroreceptor reflex is presented. Arterial hypertension in this case is accompanied by increase activity of sympathetic nervous system. The supposition that arterial baroreceptor reflex place a role in long time regulation of arterial blood pressure is expressed.

  16. Arterial function of carotid and brachial arteries in postmenopausal vegetarians

    PubMed Central

    Su, Ta-Chen; Torng, Pao-Ling; Jeng, Jiann-Shing; Chen, Ming-Fong; Liau, Chiau-Suong

    2011-01-01

    Background: Vegetarianism is associated with a lower risk of cardiovascular disease. However, studies of arterial function in vegetarians are limited. Methods: This study investigated arterial function in vegetarianism by comparing 49 healthy postmenopausal vegetarians with 41 age-matched omnivores. The arterial function of the common carotid artery was assessed by carotid duplex, while the pulse dynamics method was used to measure brachial artery distensibility (BAD), compliance (BAC), and resistance (BAR). Fasting blood levels of glucose, lipids, lipoprotein (a), high-sensitivity C-reactive protein, homocysteine, and vitamin B12 were also measured. Results: Vegetarians had significantly lower serum cholesterol, high-density and low-density lipoprotein, and glucose compared with omnivores. They also had lower vitamin B12 but higher homocysteine levels. Serum levels of lipoprotein (a) and high-sensitivity C-reactive protein were no different between the two groups. There were no significant differences in carotid beta stiffness index, BAC, and BAD between the two groups even after adjustment for associated covariates. However, BAR was significantly lower in vegetarians than in omnivores. Multiple linear regression analysis revealed that age and pulse pressure were two important determinants of carotid beta stiffness index and BAD. Vegetarianism is not associated with better arterial elasticity. Conclusion: Apparently healthy postmenopausal vegetarians are not significantly better in terms of carotid beta stiffness index, BAC, and BAD, but have significantly decreased BAR than omnivores. Prevention of vitamin B12 deficiency might be beneficial for cardiovascular health in vegetarians. PMID:21915169

  17. Arterial function of carotid and brachial arteries in postmenopausal vegetarians.

    PubMed

    Su, Ta-Chen; Torng, Pao-Ling; Jeng, Jiann-Shing; Chen, Ming-Fong; Liau, Chiau-Suong

    2011-01-01

    Vegetarianism is associated with a lower risk of cardiovascular disease. However, studies of arterial function in vegetarians are limited. This study investigated arterial function in vegetarianism by comparing 49 healthy postmenopausal vegetarians with 41 age-matched omnivores. The arterial function of the common carotid artery was assessed by carotid duplex, while the pulse dynamics method was used to measure brachial artery distensibility (BAD), compliance (BAC), and resistance (BAR). Fasting blood levels of glucose, lipids, lipoprotein (a), high-sensitivity C-reactive protein, homocysteine, and vitamin B12 were also measured. Vegetarians had significantly lower serum cholesterol, high-density and low-density lipoprotein, and glucose compared with omnivores. They also had lower vitamin B12 but higher homocysteine levels. Serum levels of lipoprotein (a) and high-sensitivity C-reactive protein were no different between the two groups. There were no significant differences in carotid beta stiffness index, BAC, and BAD between the two groups even after adjustment for associated covariates. However, BAR was significantly lower in vegetarians than in omnivores. Multiple linear regression analysis revealed that age and pulse pressure were two important determinants of carotid beta stiffness index and BAD. Vegetarianism is not associated with better arterial elasticity. Apparently healthy postmenopausal vegetarians are not significantly better in terms of carotid beta stiffness index, BAC, and BAD, but have significantly decreased BAR than omnivores. Prevention of vitamin B12 deficiency might be beneficial for cardiovascular health in vegetarians.

  18. Additive Role of the Vestibular End Organ and Baroreceptors on the Regulation of Blood Pressure in Rats

    PubMed Central

    Lan, Yan; Yang, Yan-Zhao; Jiang, Xian; Li, Li-Wei; Jin, Guang-Shi; Kim, Min Sun

    2013-01-01

    Contribution of the vestibular end organ to regulation of arterial pressure was quantitatively compared with the role of baroreceptors in terms of baroreflex sensitivity and c-Fos protein expression in the rostral ventrolateral medulla (RVLM). Baroreflex sensitivity and c-Fos protein expression in the RVLM were measured in conscious rats that had undergone bilateral labyrinthectomy (BL) and/or baroreceptor unloading. BL attenuated baroreflex sensitivity during intravenous infusion of sodium nitroprusside (SNP), but did not significantly affect the sensitivity following infusion of phenylephrine (PE). Baroreflex sensitivity became positive following sinoaortic denervation (SAD) during infusion of PE and attenuated sensitivity during infusion of SNP. Baroreflex sensitivity also became positive following double ablation (BL+SAD) during infusion of PE, and attenuated sensitivity during infusion of SNP. c-Fos protein expression increased significantly in the RVLM in the sham group after SNP administration. However, the BL, SAD, and SAD+BL groups showed significant decreases in c-Fos protein expression compared with that in the sham group. The SAD group showed more reduced c-Fos protein expression than that in the BL group, and the SAD+BL group showed less expression than that in the SAD group. These results suggest that the vestibular system cooperates with baroreceptors to maintain arterial pressure during hypotension but that baroreceptors regulate arterial pressure during both hypotension and hypertension. Additionally, afferent signals for maintaining blood pressure from the vestibular end organs and the baroreceptors may be integrated in the RVLM. PMID:23946697

  19. Diet-induced obesity severely impairs myelinated aortic baroreceptor reflex responses.

    PubMed

    McCully, Belinda H; Brooks, Virginia L; Andresen, Michael C

    2012-05-15

    Diet-induced obesity (DIO) attenuates the arterial cardiac baroreceptor reflex, but the mechanisms and sites of action are unknown. This study tested the hypothesis that DIO impairs central aortic baroreceptor pathways. Normal chow control (CON) and high-fat-chow obesity-resistant (OR) and obesity-prone (OP) rats were anesthetized (inactin, 120 mg/kg) and underwent sinoaortic denervation. The central end of the aortic depressor nerve (ADN) was electrically stimulated to generate frequency-dependent baroreflex curves (5-100 Hz) during selective activation of myelinated (A-fiber) or combined (A- and C-fiber) ADN baroreceptors. A mild stimulus (1 V) that activates only A-fiber ADN baroreceptors induced robust, frequency-dependent depressor and bradycardic responses in CON and OR rats, but these responses were completely abolished in OP rats. Maximal activation of A fibers (3 V) elicited frequency-dependent reflexes in all groups, but a dramatic deficit was still present in OP rats. Activation of all ADN baroreceptors (20 V) evoked even larger reflex responses. Depressor responses were nearly identical among groups, but OP rats still exhibited attenuated bradycardia. In separate groups of rats, the reduced heart rate (HR) response to maximal activation of ADN A fibers (3 V) persisted in OP rats following pharmacological blockade of β(1)-adrenergic or muscarinic receptors, suggesting deficits in both parasympathetic nervous system (PNS) and sympathetic nervous system (SNS) reflex pathways. However, the bradycardic responses to direct efferent vagal stimulation were similar among groups. Taken together, our data suggest that DIO severely impairs the central processing of myelinated aortic baroreceptor control of HR, including both PNS and SNS components.

  20. Integrating the theories of Darwin and Bernoulli: maladaptive baroreceptor network dysfunction may explain the pathogenesis of aortic aneurysms.

    PubMed

    Conley, Buford R; Doux, John D; Lee, Patrick Y; Bazar, Kimberly A; Daniel, Stephanie M; Yun, Anthony J

    2005-01-01

    Current treatment options for aortic aneurysms are suboptimal and their pathogenic mechanisms remain unclear. We propose the existence of a coordinated multi-node baroreceptor network that measures pressures at all vascular bifurcations and enables system-wide hemodynamic coordination and vasomotor regulation, in accordance with the principle of Bernoulli. While the presence of baroreceptors at bifurcations remains unknown, behavior at the level of systems predicts their existence, possibly as glomus cell derivatives. We propose that pressure misregistration among sensor nodes at different vascular bifurcations can precipitate feed-forward dysfunctions that promote thrombosis, inflammation, and vasomotor dysregulation resulting in aneurysm formation. One example of this phenomenon is aortic aneurysm, which is currently attributed to focal anatomic defects. As plaque builds in the infrarenal aorta, the increased blood velocity through this segment can widen the difference between pressures sensed at the iliac and the renal artery bifurcations. Due to the Bernoulli effect, this change creates an incorrect impression of reduced dynamic pressure at the kidneys. The erroneous perception of hypovolemia can induce a pernicious cycle of maladaptive adrenergia and associated coagulation and thrombosis, particularly in the infrarenal aortic segment as the body attempts to normalize renal perfusion. Atherosclerosis can further exacerbate baroreceptor dysfunction by interfering with sensor biology in feed-forward fashion. Hypertension may be a consequence as well as a source of atherosclerosis and aneurysm. The described system may have evolved when trauma-related hypovolemia was a far more prevalent driver of natural selection but may be rendered maladaptive in the setting of modern stressors. Failure to address these factors may explain the suboptimal long-term outcomes with current surgical and endovascular treatments for aneurysms. Implications for other potential sensor

  1. Alteration of renal baroreceptor by salt intake in control of plasma renin activity in conscious dogs.

    PubMed

    Farhi, E R; Cant, J R; Barger, A C

    1983-07-01

    We investigated the relationship between renal arterial pressure (RAP) and systemic plasma renin activity (PRA) in five uninephrectomized conscious dogs on normal salt (80 meq Na+/day) and low salt (10 meq Na+/day) diets. The RAP was controlled by an inflatable cuff placed around the origin of the renal artery. In both salt states the PRA was an exponential function of the RAP: log (PRA) = (-0.026 X RAP) + 2 on the normal salt diet (r = 0.96) and log (PRA) = (-0.026 X RAP) + 2.5 on the low salt diet (r = 0.99). At any RAP, the value of the low salt PRA was 3 times that of the normal salt PRA. Accordingly, a reduction in salt intake increases the sensitivity of the renal baroreceptor so that the absolute value of PRA increases at any RAP, but the percentage change in PRA caused by any change in RAP is the same in both normal and low salt states.

  2. Baroreceptor sensitivity in supine man following inhalation of amyl nitrite

    SciTech Connect

    Rubal, B.J.; Moody, J.M.; Bailey, S.R. Univ. of Texas, San Antonio )

    1991-03-15

    This study compares baroreceptor sensitivity derived from high-fidelity central aortic blood pressure (BP) measurements following amyl nitrite inhalation (ANI) during BP fall and recovery in seven male subjects undergoing diagnostic catheterization for chest pain syndrome. Continuous beat-by-beat plots of BP va pulse interval revealed that all subjects exhibited a counter-clockwise loop with varying degrees of hysteresis. Baroreceptor sensitivity was derived from the slope of a linear plot of systolic BP vs pulse interval and central aortic BP. When baroreceptor sensitivities were compared during BP fall and recovery, the mean values did not differ for the group; however, the slope of regression lines differed in six of the seven subjects. In summary, this study: describes the use of hi-fi central aortic pressure recordings in assessments of baroreceptor sensitivity which avoids the influence of local BP wave reflections in determining baroreceptor sensitivity, and demonstrates the complex nature of the baroreceptor responses to ANI.

  3. Baroreceptor sensitive neurones in the anterior hypothalamus of the cat

    PubMed Central

    Spyer, K. M.

    1972-01-01

    1. The activity of 372 neurones, located within or close to the hypothalamic depressor area, was recorded on raising the pressure within a vascularly isolated carotid sinus. 2. When the intrasinusal pressure was raised abruptly to 200 mm Hg the activity of fifteen neurones was enhanced and of six inhibited. 3. The neurones exhibiting excitation on baroreceptor afferent stimulation were broadly divisible into two groups. Nine neurones responded with a marked increase in discharge frequency, the other six responded with a `burst-on' discharge with a minimum latency of 90 msec. Excitation in both cases was always within 500 msec of the presentation of the stimulus. No functional distinction has been drawn from these responses. 4. Evidence has been obtained suggesting that the responses of both types of neurone showing excitation may be potentiated using a pulsatile rather than static stimulus. 5. The role of the neurones in the integration of the carotid sinus baroreceptor reflex is discussed. It is suggested that the hypothalamic depressor area represents the rostral extension of the integrative centre for the reflex. PMID:5039985

  4. [Left ventricular function in pulmonary arterial hypertension].

    PubMed

    Khomaziuk, V A

    1998-12-01

    Echocardiographic evaluation was done of left ventricular functional state in 90 patients with primary and secondary pulmonary arterial hypertension with and without intercavitary shunting. Changes in left ventricular function were identified in 86% cases; they reflected disturbances in both ventricles compensatory interaction. The degree of changes depended on the degree of dilatation of the right ventricle and level of interchamber shunting.

  5. Inhibition of the baroreceptor reflex on stimulation in the brain stem defence centre

    PubMed Central

    Coote, J. H.; Hilton, S. M.; Perez-Gonzalez, J. F.

    1979-01-01

    1. In anaesthetized cats, the pattern of cardiovascular response characteristic of the defence reaction has been elicited by localized electrical stimulation within the appropriate region of the hypothalamus. The baroreceptor reflex response has been elicited by raising the pressure in a blind sac preparation of the carotid sinus or by electrical stimulation of the sinus nerve. 2. In addition to arterial blood pressure, heart rate and regional blood flows, activity was recorded in cardiac and renal sympathetic nerves, to assess more precisely the cardiomotor and vasomotor changes during interactions between brain stem stimulation and baroreceptor activation. 3. The sympatho-inhibitory and depressor effects of carotid sinus stimulation or electrical stimulation of the sinus nerve could be completely suppressed by stimulation within the hypothalamic defence area, as could the reflex bradycardia. It is concluded that this suppression is effected through the central nervous system. 4. Stimulation at points in the hypothalamus close to, but outside, the defence area, and which elicited increases in arterial pressure and sympathetic activity of similar magnitude to those from the defence area itself, did not abolish the sympatho-inhibitory or depressor effects of baroreceptor activation, though the reflex bradycardia was usually inhibited. It is suggested that this less localized change results from augmentation of the central inspiratory drive which inhibits the vagal outflow to the heart. ImagesFig. 1Fig. 3Fig. 4 PMID:572871

  6. Alterations in the baroreceptor-heart rate reflex in conscious inbred polydipsic (STR/N) mice.

    PubMed

    Chu, C P; Cui, B R; Kannan, H; Qiu, D L

    2015-01-01

    STR/N is an inbred strain of mice which is known to exhibit extreme polydipsia and polyuria. We previously found central administration of angiotensin II enhanced cardiovascular responses in STR/N mice than normal mice, suggesting that STR/N mice might exhibit different cardiovascular responses. Therefore, in this study, we investigated daily mean arterial blood pressure and heart rate, and changes in the baroreceptor-heart rate reflex in conscious STR/N mice and control (ICR) mice. We found that variability in daily mean arterial blood pressure and heart rate was significantly larger in STR/N mice than in ICR mice (p<0.05). There was a stronger response to phenylephrine (PE) in STR/N mice than in ICR mice. For baroreceptor reflex sensitivity, in the rapid response period, the slopes of PE and sodium nitroprusside (SNP) were more negative in STR/N mice than in ICR mice. In the later period, the slopes of PE and SNP were negatively correlated between heart rate and blood pressure in ICR mice, but their slopes were positively correlated in STR/N mice. These results indicated that STR/N mice exhibited the different cardiovascular responses than ICR mice, suggesting that the dysfunction of baroreceptor reflex happened in conscious STR/N mice.

  7. Effects of horizontal body casting on the baroreceptor reflex control of heart rate

    NASA Technical Reports Server (NTRS)

    Billman, G. E.; Dickey, D. T.; Sandler, H.; Stone, H. L.

    1982-01-01

    The purpose of this study was to investigate the effects of long-term horizontal body position on baroreceptor reflex control of heart rate. Six male rhesus monkeys (6.2-9.4 kg) were given bolus injections of 4.0 microgram/kg, phenylephrine during each of the following conditions: awake, anesthetized (10 mg/kg ketamine HCl), and after beta-blockade (1 mg/kg propranolol HCl) before, 7, 14, and 28 days after being placed in a horizontal body cast. R-R interval vs. systolic arterial pressure was plotted, and the slope was determined by least-squares-fit linear regression. Baroreceptor slope was significantly reduced by 7 days of horizontal body position and remained attenuated throughout the 28-day restraint period both before and after beta-receptor blockade. These data are consistent with the thesis that prolonged exposure to a zero-gravity environment impairs autonomic reflex regulation of the cardiovascular system.

  8. Effects of horizontal body casting on the baroreceptor reflex control of heart rate

    NASA Technical Reports Server (NTRS)

    Billman, G. E.; Dickey, D. T.; Sandler, H.; Stone, H. L.

    1982-01-01

    The purpose of this study was to investigate the effects of long-term horizontal body position on baroreceptor reflex control of heart rate. Six male rhesus monkeys (6.2-9.4 kg) were given bolus injections of 4.0 microgram/kg, phenylephrine during each of the following conditions: awake, anesthetized (10 mg/kg ketamine HCl), and after beta-blockade (1 mg/kg propranolol HCl) before, 7, 14, and 28 days after being placed in a horizontal body cast. R-R interval vs. systolic arterial pressure was plotted, and the slope was determined by least-squares-fit linear regression. Baroreceptor slope was significantly reduced by 7 days of horizontal body position and remained attenuated throughout the 28-day restraint period both before and after beta-receptor blockade. These data are consistent with the thesis that prolonged exposure to a zero-gravity environment impairs autonomic reflex regulation of the cardiovascular system.

  9. A new method to identify dynamic transduction properties of aortic baroreceptors.

    PubMed

    Sugimachi, M; Imaizumi, T; Sunagawa, K; Hirooka, Y; Todaka, K; Takeshita, A; Nakamura, M

    1990-03-01

    We identified, in 17 alpha-chloralose-anesthetized rabbits, the dynamic transduction characteristics of the aortic arch baroreceptors using a "white-noise technique." We recorded aortic pressure and aortic depressor nerve activity while perturbing pressure by rapid, intermittent ventricular pacing (400 beats/min). Dividing the cross-power spectrum between nerve activity and pressure by the power spectrum of pressure yielded the transfer function. The gain of the transfer function increased threefold as the frequency increased from 0.005 to 5 Hz, suggesting that the baroreceptors responded primarily to dynamic rather than to static changes in pressure. To quantify the nonlinear properties of baroreceptor transduction, we compared measured instantaneous nerve activity with that linearly predicted. We demonstrated that the major nonlinearity was attributable to "threshold". The overall baroreceptor transduction properties could be represented by a cascade connection of a linear subsystem followed by a nonlinear subsystem with threshold. The white-noise technique made it possible to identify the unbiased linear properties in a nonlinear system, and thus was very useful in identifying complex biological systems.

  10. Carotid baroreceptor reflexes in humans during orthostatic stress.

    PubMed

    Cooper, V L; Hainsworth, R

    2001-09-01

    Orthostatic stress, including standing, head-up tilting and lower body suction, results in increases in peripheral vascular resistance but little or no change in mean arterial pressure. This study was undertaken to determine whether the sensitivity of the carotid baroreceptor reflex was enhanced during conditions of decreased venous return. We studied eight healthy subjects and determined responses of pulse interval (ECG) and forearm vascular resistance (mean finger blood pressure divided by Doppler estimate of brachial artery blood velocity) to graded increases and decreases in carotid transmural pressure, effected by a neck suction/pressure device. Responses were determined with and without the application of lower body negative pressure (LBNP) at -40 mmHg. Stimulus-response curves were determined as the responses to graded neck pressure changes and the differential of this provided estimates of reflex sensitivity. Changes in carotid transmural pressure caused graded changes in R-R interval and vascular resistance. The cardiac responses were unaffected by LBNP. Vascular resistance responses, however, were significantly enhanced during LBNP and the peak gain of the reflex was increased from 1.2 +/- 0.3 (mean +/- S.E.M.) to 2.2 +/- 0.3 units (P < 0.05). The increased baroreflex gain may contribute to maintenance of blood pressure during orthostatic stress and limit the pressure decreases during prolonged periods of such stress.

  11. [The effect of halothane and enflurane as well as of propanidid and ketamin on the aortic baroreceptor discharge of decerebrated cats (author's transl)].

    PubMed

    Hagenau, W; Pietsch, D; Arndt, J O

    1976-07-01

    The effect of halothane, enflurane, propanidid and ketamine on the sensitivity of the aortic baroreceptors and its quantitative relationship with arterial pressure were studied in decerebrated cats. Receptor response curves (single baroreceptor fibres of the depressor nerve) were constructed by plotting the average discharge rate (spikes/sec) against the aortic mean pressure and the effect of the anaesthetics on them was analysed. The blood pressure was changed over wide ranges by inflating a balloon placed in the thoracic part of the descending aorta through a femoral artery. Receptor sensitivity increased with halothane and enflurane, yet it decreased with propanidid. It remained uneffected duringanesthesia with ketamine. Thus, different anesthetics act differently on the afferent impulse traffic of baroreceptors. The possible role of these effects on blood pressure control during anaesthesia is discussed.

  12. Haemostatic function in coronary artery disease (CAD).

    PubMed

    Gupta, A; Sikka, M; Madan, N; Dwidedi, S; Rusia, U; Sharma, S

    1997-04-01

    Tests to evaluate haemostatic function bleeding time (BT), prothrombin time (PT) partial thromboplastin time with kaolin (PTTK), thrombin time (TT), platelet count, platelet function tests (platelet adhesiveness and microthrombus index) and plasma fibrinogen levels were performed in 30 patients of coronary artery disease (14 myocardial infarction, 16 angina pectoris) and 20 age and sex matched controls. There was no statistically significant difference in platelet adhesiveness and mean microthrombus index in patients and controls. The BT, PT, PTTK and TT were normal in all patients and controls. Stepwise logistic regression analysis showed that plasma fibrinogen was an independent risk factor in the production of CAD.

  13. Sensing of blood pressure increase by transient receptor potential vanilloid 1 receptors on baroreceptors.

    PubMed

    Sun, Hao; Li, De-Pei; Chen, Shao-Rui; Hittelman, Walter N; Pan, Hui-Lin

    2009-12-01

    The arterial baroreceptor is critically involved in the autonomic regulation of homoeostasis. The transient receptor potential vanilloid 1 (TRPV1) receptor is expressed on both somatic and visceral sensory neurons. Here, we examined the TRPV1 innervation of baroreceptive pathways and its functional significance in the baroreflex. Resiniferatoxin (RTX), an ultrapotent analog of capsaicin, was used to ablate TRPV1-expressing afferent neurons and fibers in adult rats. Immunofluorescence labeling revealed that TRPV1 immunoreactivity was present on nerve fibers and terminals in the adventitia of the ascending aorta and aortic arch, the nodose ganglion neurons, and afferent fibers in the solitary tract of the brainstem. RTX treatment eliminated TRPV1 immunoreactivities in the aorta, nodose ganglion, and solitary tract. Renal sympathetic nerve activity, blood pressure, and heart rate were recorded in anesthetized rats. The baroreflex was triggered by lowering and raising blood pressure through intravenous infusion of sodium nitroprusside and phenylephrine, respectively. Inhibition of sympathetic nerve activity and heart rate by the phenylephrine-induced increase in blood pressure was largely impaired in RTX-treated rats. The maximum gain of the baroreflex function was significantly lower in RTX-treated than vehicle-treated rats. Furthermore, blocking of TRPV1 receptors significantly blunted the baroreflex and decreased the maximum gain of baroreflex function in the high blood pressure range. Our findings provide important new information that TRPV1 is expressed along the entire baroreceptive afferent pathway. TRPV1 receptors expressed on baroreceptive nerve endings can function as mechanoreceptors to detect the increase in blood pressure and maintain the homoeostasis.

  14. Baroreceptor reflex dysfunction in the BACHD mouse model of Huntington's disease.

    PubMed

    Schroeder, Analyne M; Loh, Dawn H; Jordan, Maria C; Roos, Kenneth P; Colwell, Christopher S

    2011-11-04

    Huntington's disease is a progressive, neurodegenerative disorder that presents with a triad of clinical symptoms, which include movement abnormalities, emotional disturbance and cognitive impairment. Recent studies reported dysfunction of the autonomic nervous system in Huntington's disease patients, which may contribute to the increased incidence of cardiovascular events in this patient population that often leads to death. We measured the baroreceptor reflex, a process dependent on proper autonomic function, in the BACHD mouse model of Huntington's disease. We found a blunted response of the baroreceptor reflex as well as significantly higher daytime blood pressure in BACHD mice compared to WT controls, which are both indications of autonomic dysfunction. BACHD mice had increased heart weight to tibia length ratios at 7 and 12 mo of age suggesting hypertrophic changes of the heart, which we speculate is a response to the increased blood pressure and aberrant baroreceptor reflex. Despite these structural changes, the hearts of BACHD mice continue to function normally as assessed by echocardiographic analysis. Studies of autonomic and cardiovascular function in BACHD mice may help elucidate the pathophysiology of Huntington's disease and aid in the development of clinical strategies to offset the incidence of fatal cardiovascular events in the Huntington's disease patient population.

  15. Effect of baroreceptor reflex stimulation on blood flow to an atelectatic lung.

    PubMed

    Strawn, W B; Hall, S M; Levitzky, M G

    1982-05-01

    The effect of baroreceptor reflex stimulation by carotid sinus hypotension on the pulmonary vascular response to atelectasis was studied in eight dogs anesthetized with chloralose. Closed-chest dogs with electromagnetic flow probes previously implanted on their left (QL) and main (QT) pulmonary arteries had their left and right lungs ventilated separately. Their carotid sinuses were isolated bilaterally and perfused by a pulsatile pump with a physiological salt solution. After an initial period of bilateral 100% O2 ventilation with carotid sinus perfusion pressures (CSPP) set at each animal's initial mean arterial pressure (98 +/- 19 Torr), the left airway was occluded, QL/QT fell from 0.33 +/- 0.01 to 0.24 +/- 0.02 and PO2 fell from 323 +/- 35 Torr to 74 + 7 Torr. When CSPP was lowered to 21 +/- 3 Torr, there were no changes in QL/QT and PO2. These results suggest that stimulation of the baroreceptor reflex by carotid sinus hypotension does not interfere with the diversion of pulmonary blood flow away from a unilaterally atelectatic lung.

  16. Arterial structure and function in vascular ageing: are you as old as your arteries?

    PubMed

    Thijssen, Dick H J; Carter, Sophie E; Green, Daniel J

    2016-04-15

    Advancing age may be the most potent independent predictor of future cardiovascular events, a relationship that is not fully explained by time-related changes in traditional cardiovascular risk factors. Since some arteries exhibit differential susceptibility to atherosclerosis, generalisations regarding the impact of ageing in humans may be overly simplistic, whereas in vivo assessment of arterial function and health provide direct insight. Coronary and peripheral (conduit, resistance and skin) arteries demonstrate a gradual, age-related impairment in vascular function that is likely to be related to a reduction in endothelium-derived nitric oxide bioavailability and/or increased production of vasoconstrictors (e.g. endothelin-1). Increased exposure and impaired ability for defence mechanisms to resist oxidative stress and inflammation, but also cellular senescence processes, may contribute to age-related changes in vascular function and health. Arteries also undergo structural changes as they age. Gradual thickening of the arterial wall, changes in wall content (i.e. less elastin, advanced glycation end-products) and increase in conduit artery diameter are observed with older age and occur similarly in central and peripheral arteries. These changes in structure have important interactive effects on artery function, with increases in small and large arterial stiffness representing a characteristic change with older age. Importantly, direct measures of arterial function and structure predict future cardiovascular events, independent of age or other cardiovascular risk factors. Taken together, and given the differential susceptibility of arteries to atherosclerosis in humans, direct measurement of arterial function and health may help to distinguish between biological and chronological age-related change in arterial health in humans.

  17. Impact of radial artery cannulation for coronary angiography and angioplasty on radial artery function.

    PubMed

    Burstein, Jason M; Gidrewicz, Dominica; Hutchison, Stuart J; Holmes, Kate; Jolly, Sanjit; Cantor, Warren J

    2007-02-15

    The radial artery is commonly used as a conduit in coronary artery bypass grafting. No data exist on the effects of radial sheath insertion on radial artery function. Because many patients considered for coronary artery bypass grafting have had previous radial procedures, it is important to understand any effects radial sheath insertion may have on radial artery function. Twenty-two patients who underwent elective coronary angiography or angioplasty with a 6Fr sheath through the right radial artery were studied. Radial artery function was assessed using ultrasound to measure flow-mediated dilation (FMD). Reactive hyperemia was produced by 5-minute cuff inflation on the arm to suprasystolic pressures. Radial artery diameter was measured at rest and 1 minute after cuff deflation. FMD was expressed as percent change in radial diameter compared with at rest. In all cases, the left radial artery was studied as a control. Patients were studied before sheath insertion, immediately after sheath insertion, and 6 weeks after sheath insertion. The FMD of the cannulated arm was 13.2% before sheath insertion versus 3.6% immediately after sheath insertion (p <0.01) and 0.2% (p <0.01) 9 weeks after sheath insertion. In contrast, there were no significant changes in the noncannulated arm at either time point. In conclusion, radial artery sheath insertion for coronary angiography or angioplasty results in immediate and persistent blunting of FMD, suggesting severe vasomotor dysfunction. Radial artery sheath insertion has important effects on radial artery function that must be considered when selecting radial conduits for coronary artery bypass grafting.

  18. Signal transduction of aortic and carotid sinus baroreceptors is not modified by central command during spontaneous motor activity in decerebrate cats.

    PubMed

    Matsukawa, Kanji; Ishii, Kei; Kadowaki, Akito; Ishida, Tomoko; Idesako, Mitsuhiro; Liang, Nan

    2014-05-15

    Our laboratory has suggested that central command provides selective inhibition of the cardiomotor component of aortic baroreflex at the start of exercise, preserving carotid sinus baroreflex. It is postulated that central command may modify the signal transduction of aortic baroreceptors, so as to decrease aortic baroreceptor input to the cardiovascular centers, and, thereby, can cause the selective inhibition of aortic baroreflex. To test the hypothesis, we directly analyzed the responses in multifiber aortic nerve activity (AoNA) and carotid sinus nerve activity (CsNA) during spontaneous motor activity in decerebrate, paralyzed cats. The increases of 62-104% in mean AoNA and CsNA were found during spontaneous motor activity, in proportion to a rise of 35 ± 3 mmHg (means ± SE) in mean arterial blood pressure (MAP), and had an attenuating tendency by restraining heart rate (HR) at the lower intrinsic frequency of 154 ± 6 beats/min. Brief occlusion of the abdominal aorta was conducted before and during spontaneous motor activity to produce a mechanically evoked increase in MAP and, thereby, to examine the stimulus-response relationship of arterial baroreceptors. Although the sensitivity of the MAP-HR baroreflex curve was markedly blunted during spontaneous motor activity, the stimulus-response relationships of AoNA and CsNA were not influenced by spontaneous motor activity, irrespective of the absence or presence of the HR restraint. Thus, it is concluded that aortic and carotid sinus baroreceptors can code beat-by-beat blood pressure during spontaneous motor activity in decerebrate cats and that central command is unlikely to modulate the signal transduction of arterial baroreceptors. Copyright © 2014 the American Physiological Society.

  19. Inhibition of atrial receptor-induced renal responses by stimulation of carotid baroreceptors in anaesthetized dogs.

    PubMed Central

    Karim, F; Majid, D S

    1991-01-01

    excitation of carotid baroreceptors can completely inhibit the reflex renal haemodynamic and functional responses to atrial receptor stimulation. PMID:1886066

  20. Spaceflight alters autonomic regulation of arterial pressure in humans

    NASA Technical Reports Server (NTRS)

    Fritsch-Yelle, Janice M.; Charles, John B.; Jones, Michele M.; Beightol, Larry A.; Eckberg, Dwain L.

    1994-01-01

    Spaceflight is associated with decreased orthostatic tolerance after landing. Short-duration spaceflight (4 - 5 days) impairs one neutral mechanism: the carotid baroreceptor-cardiac reflex. To understand the effects of longer-duration spaceflight on baroreflex function, we measured R-R interval power spectra, antecubital vein plasma catecholamine levels, carotid baroreceptor-cardiac reflex responses, responses to Valsalva maneuvers, and orthostatic tolerance in 16 astronauts before and after shuttle missions lasting 8 - 14 days. We found the following changes between preflight and landing day: (1) orthostatic tolerance decreased; (2) R-R interval spectral power in the 0.05- to 0.15-Hz band increased; (3) plasma norepinephrine and epinephrine levels increased; (4) the slope, range, and operational point of the carotid baroreceptor cardiac reflex response decreased; and (5) blood pressure and heart rate responses to Valsalva maneuvers were altered. Autonomic changes persisted for several days after landing. These results provide further evidence of functionally relevent reductions in parasympathetic and increases in sympathetic influences on arterial pressure control after spaceflight.

  1. Functional impairment of precerebral arteries in Huntington disease.

    PubMed

    Kobal, Jan; Cankar, Ksenija; Pretnar, Janja; Zaletel, Marjan; Kobal, Lucijan; Teran, Natasa; Melik, Ziva

    2017-01-15

    Cardiovascular pathology of Huntington disease (HD) appears to be complex; while microvascular dysfunction seems to appear early, deaths from cardiomyopathy and stroke might occur in the late phase of HD. Our study evaluated global risk factors for coronary heart disease (CHD), structure and function of precerebral arteries in 41 HD subjects and 41 matched controls. HD subjects were divided into groups by the United Huntington disease rating scale (presymptomatic-PHD, early-EHD, midstage-MHD and late-LHD). CHD risk factors assessment and Doppler examination of precerebral arteries were performed, including measurements of the carotid artery intima-media thickness (IMT), and parameters indicating local carotid artery distensibility (stiffness index β, pulse wave velocity, pressure strain elasticity module and carotid artery compliance). In the HD and controls we identified a comparable number of non-obstructive plaques (<50% lumen narrowing). No obstructive plaques (>50% lumen narrowing) were found. There was significantly increased IMT in MHD. In PHD and EHD the parameters of arterial stiffness were significantly higher and the carotid artery compliance was significantly lower. Our results reveal functional vascular pathology in PHD, EHD, and MHD. Precerebral arteries dysfunction in HD therefore appears to be mostly functional and in agreement with recently described autonomic nervous system changes in HD. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Peripheral Endothelial Function After Arterial Switch Operation for D-looped Transposition of the Great Arteries.

    PubMed

    Sun, Heather Y; Stauffer, Katie Jo; Nourse, Susan E; Vu, Chau; Selamet Tierney, Elif Seda

    2017-03-27

    Coronary artery re-implantation during arterial switch operation in patients with D-looped transposition of the great arteries (D-TGA) can alter coronary arterial flow and increase shear stress, leading to local endothelial dysfunction, although prior studies have conflicting results. Endothelial pulse amplitude testing can predict coronary endothelial dysfunction by peripheral arterial testing. This study tested if, compared to healthy controls, patients with D-TGA after arterial switch operation had peripheral endothelial dysfunction. Patient inclusion criteria were (1) D-TGA after neonatal arterial switch operation; (2) age 9-29 years; (3) absence of known cardiovascular risk factors such as hypertension, diabetes, hypercholesterolemia, vascular disease, recurrent vasovagal syncope, and coronary artery disease; and (4) ability to comply with overnight fasting. Exclusion criteria included (1) body mass index ≥85th percentile, (2) use of medications affecting vascular tone, or (3) acute illness. We assessed endothelial function by endothelial pulse amplitude testing and compared the results to our previously published data in healthy controls (n = 57). We tested 20 D-TGA patients (16.4 ± 4.8 years old) who have undergone arterial switch operation at a median age of 5 days (0-61 days). Endothelial pulse amplitude testing indices were similar between patients with D-TGA and controls (1.78 ± 0.61 vs. 1.73 ± 0.54, p = 0.73).In our study population of children and young adults, there was no evidence of peripheral endothelial dysfunction in patients with D-TGA who have undergone arterial switch operation. Our results support the theory that coronary arterial wall thickening and abnormal vasodilation reported in these patients is a localized phenomenon and not reflective of overall atherosclerotic burden.

  3. Static and dynamic responses of carotid sinus baroreceptors in dogs with chronic volume overload.

    PubMed Central

    Niebauer, M; Zucker, I H

    1985-01-01

    In this study we determined if there are any alterations in carotid sinus baroreceptor discharge in a model of heart failure in the dog. The left carotid sinus was isolated and perfused at 100 mmHg with a modified Krebs-Henseleit solution. Two groups of dogs were used: a normal group and a group with a chronic aorto-caval fistula (a.v.f.) of up to 20 weeks duration. The a.v.f. group had a significantly elevated heart rate and left ventricular end diastolic pressure as well as an increased arterial pulse pressure compared to normals. However, mean arterial pressure measured in the aortic arch was not significantly different. Carotid sinus pressure-discharge curves were constructed during increases in carotid sinus pressure by steps and by ramps of pressure change up to 200 mmHg/s. Carotid sinus diameter was also measured using sonomicrometer crystals. In six dogs from each group the sodium, potassium and water content of the right carotid sinus was measured. Several parameters of second order polynomial curves that were fitted to the data were compared between the two groups for step and ramp increases in pressure. These included maximum baroreceptor gain, threshold pressure and plateau pressure. Baroreceptor gain was significantly lower in the a.v.f. group for the step and lowest ramp rate pressure changes. Threshold pressure was significantly higher for the a.v.f. group for steps and the three slowest ramp rates. Plateau pressures were significantly higher for the steps and lowest ramp rate. The carotid sinus strain that was produced at any given carotid sinus pressure was not significantly different between the two groups. In addition, there was no difference in the sodium, potassium or water content of the carotid sinus between the two groups. It was concluded that there is a depression of the static discharge characteristics in this model of heart failure which is not due to an alteration in electrolyte or water content or to the compliance of the carotid sinus

  4. Lateralization of expression of neural sympathetic activity to the vessels and effects of carotid baroreceptor stimulation

    PubMed Central

    Diedrich, André; Porta, Alberto; Barbic, Franca; Brychta, Robert J.; Bonizzi, Pietro; Diedrich, Laura; Cerutti, Sergio; Robertson, David; Furlan, Raffaello

    2009-01-01

    Human studies suggest that cardiovascular neural sympathetic control is predominantly modulated by the right cerebral hemisphere. It is unknown whether post-ganglionic sympathetic activity [muscle sympathetic nerve activity (MSNA)] shows any functional asymmetry. Eight right-handed volunteers (3 women and 5 men, 32 ± 2 yr of age) underwent ECG, beat-by-beat blood pressure, respiratory activity, and simultaneous right and left MSNA recordings during spontaneous and controlled breathing (CB, 15 breaths/min, 0.25 Hz). Dynamic carotid baroreceptor stimulation was obtained by 0.1-Hz sinusoidal suction, from 0 to −50 mmHg, randomly applied to the right, left, and combined right and left sides of the neck during CB. Laterality was assessed by changes in the MSNA burst rate (in bursts/min, and bursts/100 beats), strength [amplitude (A) and area (AA)], and the oscillatory component at 0.1 Hz during baroreceptor stimulation. Amplitude parameters were normalized by CB burst mean amplitude and area of the same side. At rest, the right and left MSNA burst rate and total MSNA activity were similar. Conversely, the right MSNA normalized burst AN (1.36 ± 0.18) and AAN (1.31 ± 0.16) were larger than the left MSNA AN (1.04 ± 0.09) and AAN (1.02 ± 0.08). Unilateral and bilateral carotid baroreflex stimulation abolished the right prevalence of AN and AAN. In conclusion, the right lateralization of sympathetic activity to the vessels is indicated by normalized burst strength parameters of bilateral MSNA recordings at rest during spontaneous breathing. Carotid baroreceptor stimulation disrupted such expression of MSNA lateralization possibly by disturbing the synchronizing action of right cerebral hemisphere. PMID:19363133

  5. Intermediate-term survival and functional results after arterial repair for transposition of the great arteries.

    PubMed

    Lupinetti, F M; Bove, E L; Minich, L L; Snider, A R; Callow, L B; Meliones, J N; Crowley, D C; Beekman, R H; Serwer, G; Dick, M

    1992-03-01

    An assessment of late morbidity and mortality is essential before arterial repair can be considered truly corrective for patients with transposition of the great arteries. We describe the early and intermediate-term results in 126 patients who underwent arterial repair. Operation was performed at a median age of 6 days, with 76 patients operated on within the first 7 days of life. Coronary artery anatomy differed from the usual arrangement in 37 patients. Simultaneous procedures included ventricular septal defect closure (35) and repair of interrupted aortic arch (2) or coarctation (5). Hospital mortality was seven of 126 (5.5%), with three deaths among the most recent 100 patients (3%). There were one late, noncardiac death and one late death after reoperation. Reoperation for pulmonary artery stenosis was required in 10 of the first 63 patients (16%), all of whom underwent pulmonary artery reconstruction with separate patches for closure of the coronary excision sites. Of the last 63 patients, all of whom underwent pulmonary artery reconstruction with a single pantaloon-shaped pericardial patch, one (2%) required reoperation for pulmonary artery stenosis. Doppler flow studies and echocardiography performed in 115 of 119 surviving patients at a mean of 12 months after repair demonstrated normal left ventricular function, minimal left ventricular outflow gradients, and no more than trivial aortic regurgitation. Peak gradient across the right ventricular outflow tract was 19 +/- 3 mm Hg in patients with separate pulmonary artery patches and 5 +/- 2 mm Hg in those with a single pantaloon patch (p = 0.0001). Follow-up is 96% complete from 1 month to 8 years after operation (mean 2.5 years). The actuarial survival rate at 5 years, including operative mortality, was 92%. All patients are in sinus rhythm, and none requires antiarrhythmic medications. These data suggest that pulmonary artery reconstruction with a single pantaloon patch may be associated with a decreased

  6. Greater impairments in cerebral artery compared with skeletal muscle feed artery endothelial function in a mouse model of increased large artery stiffness.

    PubMed

    Walker, Ashley E; Henson, Grant D; Reihl, Kelly D; Morgan, R Garrett; Dobson, Parker S; Nielson, Elizabeth I; Ling, Jing; Mecham, Robert P; Li, Dean Y; Lesniewski, Lisa A; Donato, Anthony J

    2015-04-15

    Increased large artery stiffness is a hallmark of arterial dysfunction with advancing age and is also present in other disease conditions such as diabetes. Increased large artery stiffness is correlated with resistance artery dysfunction in humans. Using a mouse model of altered arterial elastin content, this is the first study to examine the cause-and-effect relationship between large artery stiffness and peripheral resistance artery function. Our results indicate that mice with genetically greater large artery stiffness have impaired cerebral artery endothelial function, but generally preserved skeletal muscle feed artery endothelial function. The mechanisms for impaired cerebral artery endothelial function are reduced nitric oxide bioavailability and increased oxidative stress. These findings suggest that interventions that target large artery stiffness may be important to reduce disease risk associated with cerebral artery dysfunction in conditions such as advancing age. Advancing age as well as diseases such as diabetes are characterized by both increased large artery stiffness and impaired peripheral artery function. It has been hypothesized that greater large artery stiffness causes peripheral artery dysfunction; however, a cause-and-effect relationship has not previously been established. We used elastin heterozygote mice (Eln(+/-) ) as a model of increased large artery stiffness without co-morbidities unrelated to the large artery properties. Aortic stiffness, measured by pulse wave velocity, was ∼35% greater in Eln(+/-) mice than in wild-type (Eln(+/+) ) mice (P = 0.04). Endothelium-dependent dilatation (EDD), assessed by the maximal dilatation to acetylcholine, was ∼40% lower in Eln(+/-) than Eln(+/+) mice in the middle cerebral artery (MCA, P < 0.001), but was similar between groups in the gastrocnemius feed arteries (GFA, P = 0.79). In the MCA, EDD did not differ between groups after incubation with the nitric oxide (NO) synthase inhibitor N

  7. Adapted Transfer Function Design for Coronary Artery Evaluation

    NASA Astrophysics Data System (ADS)

    Glaßer, Sylvia; Oeltze, Steffen; Hennemuth, Anja; Wilhelmsen, Skadi; Preim, Bernhard

    We present an approach for adapted transfer function (TF) specification to highlight pathologic changes of the coronary artery vessel wall based on contrast medium-enhanced computed tomography (CT) datasets. The TFs are combined with common visualization techniques for the evaluation of coronary arteries in CT image data. The presented mapping of CT values in Hounsfield Units (HU) to optical properties such as color and opacity leads to a different color coding for different plaque types.

  8. [Disorders of neurocognitive function after coronary artery bypass grafting].

    PubMed

    Ieva, Norkiene; Samalavicius, Robertas; Misiūriene, Irina; Valaikiene, Jurgita; Baublys, Alis; Uzdavinys, Giedrius

    2004-01-01

    Neurocognitive dysfunction still remains a frequent problem after heart surgery, complicating early recovery and strongly affecting postoperative quality of life. The aim of our study was to determine incidence of cognitive dysfunction after coronary artery bypass grafting for patients of low risk group and to find operative and postoperative factors associated with early cognitive impairment. Using exclusion criteria, which are known as risk factors for postoperative neurological complications we selected a group of 30 coronary artery bypass grafting patients. The day before surgery and 7 to 8 days after operation we evaluated cognitive function of each patient using MMSE and standardized test battery of five neuropsychological tests. The incidence of cognitive decline was evaluated using composite z scores and 1 SD criteria. Preoperative ultrasound screening of asymptomatic carotid artery was performed for each patient. Early postoperative cognitive dysfunction was present in 13 (46.3%) of patients. Patients with cognitive decline more often had asymptomic, hemodynamicly significant carotid artery stenosis. Duration of operation and coronary artery bypass time was longer in cognitive dysfunction group. As well there were more grafts performed to this group of patients. We noticed a relationship between lower temperature during coronary artery bypass and cognitive impairment. Incidence of cognitive dysfunction for patients of low risk group was 46.3%. Cognitive decline was associated with prolonged coronary artery bypass, operation time and number of grafts.

  9. Baroreceptor mediated blood pressure regulation is not affected during dose dependent inhibition of prostatic contractions by terazosin.

    PubMed

    Pawar, A; Fahim, M

    2004-10-01

    Benign prostatic hyperplasia (BPH), common in aging males is often treated with alpha1-adrenoceptor (AR) antagonists. In view of known hypotensive effect of most of the alpha1-AR antagonists, this work examined the effect of a selected alpha1-AR antagonist, terazosin on the baroreceptor mediated regulation of blood pressure. The three doses of terazosin (10, 100, 300 microg/kg body weight) used in anesthetized dogs inhibited in a dose-dependent manner the prostatic contractions and rise in blood pressure induced by phenylphrine. Impairment of arterial baroreflex, an important neural regulatory mechanism for the maintenance of normal arterial pressure, by alpha1-AR antagonist (prazosin) has been suggested in an earlier study. Hence, the effects of terazosin in doses 10, 100 and 300 microg/kg on baroreflex sensitivity (calculated as the ratio of heart rate change to acute increase in blood pressure by phenylephrine) were investigated. Terazocin did not produce any change in the baroreflex sensitivity. Therefore, in the absence of any adverse effect on the baroreceptor mediated regulation of the blood pressure, terazosin can be treated as a safer drug for the symptomatic treatment of BPH.

  10. Effects of chronic baroreceptor unloading on blood pressure in the dog.

    PubMed

    Thrasher, Terry N

    2005-04-01

    We have developed a new model of chronic baroreceptor unloading (CBU) in the dog. Initial characterization of the model indicated that CBU increased mean arterial pressure (MAP) by an average of 22 mmHg for 7 days. The goal of the present study was to replicate the previous study using telemetry to record MAP continuously and to determine the effects of CBU (n = 7) on chronic regulation of MAP. We also prepared a group of dogs with sinoaortic denervation (SAD, n = 6) to compare the time course of changes in MAP in the two models. Control levels (7 day average +/- SE) of MAP in the CBU and SAD groups were 94 +/- 2 and 94 +/- 1 mmHg, respectively. MAP averaged 124 +/- 8 and 103 +/- 4 mmHg during the first and second weeks after SAD (both P < 0.05) and then declined to levels not different from control during weeks 3-5. In the CBU group, MAP averaged 120 +/- 4 mmHg during the first week, declined to 111 +/- 4 mmHg during the second week, and stabilized at 104 mmHg during weeks 3-5 (all P < 0.05 compared with control). Plasma norepinephrine levels were increased significantly for the first week after SAD and for 2 wk after CBU but were not different from control for the remainder of the study. These results indicate that the initial increase in MAP after CBU is not sustained but declines to a level that is modestly higher than control. However, because MAP did not fall to control levels, the results are compatible with the hypothesis that baroreceptor input can influence the long-term level of MAP.

  11. Quantitative Amyloid Imaging Using Image-Derived Arterial Input Function

    PubMed Central

    Su, Yi; Blazey, Tyler M.; Snyder, Abraham Z.; Raichle, Marcus E.; Hornbeck, Russ C.; Aldea, Patricia; Morris, John C.; Benzinger, Tammie L. S.

    2015-01-01

    Amyloid PET imaging is an indispensable tool widely used in the investigation, diagnosis and monitoring of Alzheimer’s disease (AD). Currently, a reference region based approach is used as the mainstream quantification technique for amyloid imaging. This approach assumes the reference region is amyloid free and has the same tracer influx and washout kinetics as the regions of interest. However, this assumption may not always be valid. The goal of this work is to evaluate an amyloid imaging quantification technique that uses arterial region of interest as the reference to avoid potential bias caused by specific binding in the reference region. 21 participants, age 58 and up, underwent Pittsburgh compound B (PiB) PET imaging and MR imaging including a time-of-flight (TOF) MR angiography (MRA) scan and a structural scan. FreeSurfer based regional analysis was performed to quantify PiB PET data. Arterial input function was estimated based on coregistered TOF MRA using a modeling based technique. Regional distribution volume (VT) was calculated using Logan graphical analysis with estimated arterial input function. Kinetic modeling was also performed using the estimated arterial input function as a way to evaluate PiB binding (DVRkinetic) without a reference region. As a comparison, Logan graphical analysis was also performed with cerebellar cortex as reference to obtain DVRREF. Excellent agreement was observed between the two distribution volume ratio measurements (r>0.89, ICC>0.80). The estimated cerebellum VT was in line with literature reported values and the variability of cerebellum VT in the control group was comparable to reported variability using arterial sampling data. This study suggests that image-based arterial input function is a viable approach to quantify amyloid imaging data, without the need of arterial sampling or a reference region. This technique can be a valuable tool for amyloid imaging, particularly in population where reference normalization

  12. Quantitative amyloid imaging using image-derived arterial input function.

    PubMed

    Su, Yi; Blazey, Tyler M; Snyder, Abraham Z; Raichle, Marcus E; Hornbeck, Russ C; Aldea, Patricia; Morris, John C; Benzinger, Tammie L S

    2015-01-01

    Amyloid PET imaging is an indispensable tool widely used in the investigation, diagnosis and monitoring of Alzheimer's disease (AD). Currently, a reference region based approach is used as the mainstream quantification technique for amyloid imaging. This approach assumes the reference region is amyloid free and has the same tracer influx and washout kinetics as the regions of interest. However, this assumption may not always be valid. The goal of this work is to evaluate an amyloid imaging quantification technique that uses arterial region of interest as the reference to avoid potential bias caused by specific binding in the reference region. 21 participants, age 58 and up, underwent Pittsburgh compound B (PiB) PET imaging and MR imaging including a time-of-flight (TOF) MR angiography (MRA) scan and a structural scan. FreeSurfer based regional analysis was performed to quantify PiB PET data. Arterial input function was estimated based on coregistered TOF MRA using a modeling based technique. Regional distribution volume (VT) was calculated using Logan graphical analysis with estimated arterial input function. Kinetic modeling was also performed using the estimated arterial input function as a way to evaluate PiB binding (DVRkinetic) without a reference region. As a comparison, Logan graphical analysis was also performed with cerebellar cortex as reference to obtain DVRREF. Excellent agreement was observed between the two distribution volume ratio measurements (r>0.89, ICC>0.80). The estimated cerebellum VT was in line with literature reported values and the variability of cerebellum VT in the control group was comparable to reported variability using arterial sampling data. This study suggests that image-based arterial input function is a viable approach to quantify amyloid imaging data, without the need of arterial sampling or a reference region. This technique can be a valuable tool for amyloid imaging, particularly in population where reference normalization may

  13. Impact of pubertal development on endothelial function and arterial elasticity.

    PubMed

    Marlatt, Kara L; Steinberger, Julia; Dengel, Donald R; Sinaiko, Alan; Moran, Antoinette; Chow, Lisa S; Steffen, Lyn M; Zhou, Xia; Kelly, Aaron S

    2013-11-01

    Little is known about the relation of pubertal development on endothelial function and arterial elasticity in children and adolescents; therefore, we compared brachial artery flow-mediated dilation and carotid artery elasticity across Tanner (pubertal) stages in children and adolescents. Blood pressure, fasting lipids, glucose and insulin, body fat, insulin sensitivity adjusted for lean body mass, brachial flow-mediated dilation (percent dilation and area under the curve), endothelium-independent dilation (peak dilation and area under the curve), and carotid artery elasticity were evaluated across pubertal stages (Tanner I vs Tanner II-IV vs Tanner V) in 344 children and adolescents (184 males, 160 females; ages 6 to 21 years). One hundred twenty-four subjects (mean age 8.23 ± 0.15 years; 52 females) were Tanner stage I; 105 subjects (mean age 13.19 ± 0.17 years; 47 females) were Tanner stages II-IV; and 115 subjects (mean age 17.19 ± 0.16 years; 61 females) were Tanner stage V. There were no significant differences for any of the measures of vascular structure and function across pubertal stages. Results of the current study indicate that smooth-muscle and endothelial function, as well as carotid artery elasticity, do not differ throughout pubertal development and that accounting for pubertal stage when reporting vascular data in children and adolescents may be unnecessary. Copyright © 2013 Mosby, Inc. All rights reserved.

  14. Renal Artery Stenting in Patients with a Solitary Functioning Kidney

    SciTech Connect

    Cioni, Roberto; Vignali, Claudio; Petruzzi, Pasquale; Neri, Emanuele; Caramella, Davide; Vagli, Paola; Bargellini, Irene; Napoli, Vinicio; Pinto, Stefania; Bartolozzi, Carlo

    2001-12-15

    Purpose: To retrospectively evaluate the results of renal artery stenting in patients with renovascular disease and a solitary functioning kidney.Methods: Palmazstents were placed in 16 patients with a solitary functioning kidney,renal artery stenosis, hypertension and renal failure. Stenoses were evaluated with color Doppler ultrasound, MR angiography and digital subtraction angiography (DSA). Indications for stenting were: recoil after percutaneous transluminal renal angioplasty (PTRA) (63%),arterial dissection after PTRA (13%) and primary stenting (25%).Immediate results were evaluated by DSA. On follow-up (6-36 months),patients underwent periodical evaluation of clinical conditions (blood pressure and serum creatinine level) and stent patency, by means of color Doppler ultrasound.Results: Stent placement was successful in all patients (100%). Cumulative primary patency rate was: 100% at 1 day, 93.75% at 6 months, 81.25% at 12 months and 75% at 24 months. A significant reduction in diastolic blood pressure occurred (mean {+-} SD 104 {+-} 6 vs 92 {+-} 3;p < 0.05); renal function improved or stabilized in over 80% of patients. However, there was no significant difference in the creatinine values before and after treatment (mean {+-} SD 200 {+-} 142 mmol/l vs 197 {+-} 182 mmol/l; p> 0.05).Conclusion: Renal artery stenting, both after PTRA and as primary stenting, represents a safe procedure, able to preserve renal function in patients with a solitary functioning kidney.

  15. Chemoreceptors, Baroreceptors, and Autonomic Deregulation in Children with Obstructive Sleep Apnea

    PubMed Central

    Gozal, David; Hakim, Fahed; Kheirandish-Gozal, Leila

    2012-01-01

    Obstructive sleep apnea (OSA) is highly prevalent sleep disorder of breathing in both adults and children that is fraught with substantial cardiovascular morbidities, the latter being attributable to a complex interplay between intermittent hypoxia (IH), episodic hypercapnia, recurrent large intra-thoracic pressure swings, and sleep disruption. Alterations in autonomic nervous system function could underlie the perturbations in cardiovascular, neurocognitive, immune, endocrine and metabolic functions that affect many of the patients suffering from OSA. Although these issues have received substantial attention in adults, the same has thus far failed to occur in children, creating a quasi misperception that children are protected. Here, we provide a critical overview of the evidence supporting the presence of autonomic nervous system (ANS) perturbations in children with OSA, draw some parallel assessments to known mechanisms in rodents and adult humans, particularly, peripheral and central chemoreceptor and baroreceptor pathways, and suggest future research directions. PMID:22954503

  16. Circulating Angiogenic Cell Populations, Vascular Function, and Arterial Stiffness

    PubMed Central

    Cheng, Susan; Wang, Na; Larson, Martin G.; Palmisano, Joseph N.; Mitchell, Gary F.; Benjamin, Emelia J.; Vasan, Ramachandran S; Levy, Daniel; McCabe, Elizabeth L.; Vita, Joseph A.; Wang, Thomas J.; Shaw, Stanley Y.; Cohen, Kenneth S.; Hamburg, Naomi M.

    2011-01-01

    Objective Several bone marrow-derived cell populations have been identified that may possess angiogenic activity and contribute to vascular homeostasis in experimental studies. We examined the extent to which lower quantities of these circulating angiogenic cell phenotypes may be related to impaired vascular function and greater arterial stiffness. Methods We studied 1,948 Framingham Heart Study participants (mean age, 66±9 years; 54% women) who were phenotyped for circulating angiogenic cells: CD34+, CD34+/KDR+, and early outgrowth colony forming units (CFU). Participants underwent non-invasive assessments of vascular function including peripheral arterial tone (PAT), arterial tonometry, and brachial reactivity testing. Results In unadjusted analyses, higher CD34+ and CD34+/KDR+ concentrations were modestly associated with lower PAT ratio (β=−0.052±0.011, P<0.001 and β=−0.030±0.011, P=0.008, respectively) and with higher carotid-brachial pulse wave velocity (β=0.144±0.043, P=0.001 and β=0.112±0.043, P=0.009), but not with flow-mediated dilation; higher CD34+ was also associated with lower carotid-femoral pulse wave velocity (β=−0.229±0.094, P=0.015) However, only the association of lower CD34+ concentration with higher PAT ratio persisted in multivariable analyses that adjusted for standard cardiovascular risk factors. In all analyses, CFU was not associated with measures of vascular function or arterial stiffness. Conclusions In our large, community-based sample of men and women, circulating angiogenic cell phenotypes largely were not associated with measures of vascular function or arterial stiffness in analyses adjusting for traditional risk factors. PMID:22093724

  17. Arterial stiffness and arterial function in adult cyanotic patients with congenital heart disease.

    PubMed

    Trojnarska, Olga; Szczepaniak-Chicheł, Ludwina; Gabriel, Marcin; Bartczak-Rutkowska, Agnieszka; Rupa-Matysek, Joanna; Tykarski, Andrzej; Grajek, Stefan

    2017-07-01

    Mortality in cyanotic patients with congenital heart diseases (CHD) is high, mainly due to cardiovascular complications. It is known that endothelial dysfunction, increased arterial stiffness, and impaired vascular function have negative influence on cardiovascular prognosis. The aim of the study was to assess parameters of arterial stiffness and vascular dysfunction in cyanotic patients with CHD as well as their potential relation to impaired blood oxygen saturation and polycythemia parameters typical for cyanosis. A total of 36 CHD cyanotic patients (17 males) (42.3±16.3 years) and 35 healthy individuals (16 males) (39.6±10.4 years) were enrolled. Assessed parameters were intima media thickness and flow-mediated dilatation (FMD). Assessed parameters using applanation tonometry methods were aortic systolic pressure, aortic pulse pressure (AoPP), augmentation pressure (AP), augmentation index (AI), pulse pressure amplification (PPampl), and pulse wave velocity (PWV). AoPP (37.3±11.1mmHg vs. 29±6.5mmHg; p=0.002), AP (10.1±7.3mmHg vs. 1.1±3.9mmHg; p=0.00001), AI (24.7±13.5% vs. 3.0±13.6%; p=0.00001), and PWV (7.4±2.1m/s vs. 6.3±0.7m/s; p=0.003) were higher, and PPampl was lower (135.3±16.1% vs. 160.4±12.8%; p=0.00001) in the studied group compared to controls and proved the presence of the increased stiffness of arteries. Impairment of FMD was observed (9.0±5.6 vs. 10.9±4.7; p=0.04). No significant correlations were found between analyzed arterial parameters and biochemical ones characterizing cyanotic patients depicting rheological properties of blood. Cyanotic patients with CHD are characterized by increased arterial stiffness estimated with pulse wave analysis parameters and by deteriorated arterial function expressed with worse vasodilatative response in comparison with healthy population. It may confirm relevance of those mechanisms in development of increased rate of cardiovascular events in this population. Association between oxygen saturation

  18. Baroreceptor unloading does not limit forearm sweat rate during severe passive heat stress.

    PubMed

    Schlader, Zachary J; Gagnon, Daniel; Lucas, Rebekah A I; Pearson, James; Crandall, Craig G

    2015-02-15

    This study tested the hypothesis that sweat rate during passive heat stress is limited by baroreceptor unloading associated with heat stress. Two protocols were performed in which healthy subjects underwent passive heat stress that elicited an increase in intestinal temperature of ∼1.8°C. Upon attaining this level of hyperthermia, in protocol 1 (n = 10, 3 females) a bolus (19 ml/kg) of warm (∼38°C) isotonic saline was rapidly (5-10 min) infused intravenously to elevate central venous pressure (CVP), while in protocol 2 (n = 11, 5 females) phenylephrine was infused intravenously (60-120 μg/min) to return mean arterial pressure (MAP) to normothermic levels. In protocol 1, heat stress reduced CVP from 3.9 ± 1.9 mmHg (normothermia) to -0.6 ± 1.4 mmHg (P < 0.001), while saline infusion returned CVP to normothermic levels (5.1 ± 1.7 mmHg; P > 0.999). Sweat rate was elevated by heat stress (1.21 ± 0.44 mg·cm(-2)·min(-1)) but remained unchanged during rapid saline infusion (1.26 ± 0.47 mg·cm(-2)·min(-1), P = 0.5), whereas cutaneous vascular conductance increased from 77 ± 10 to 101 ± 20% of local heating max (P = 0.029). In protocol 2, MAP was reduced with heat stress from 85 ± 7 mmHg to 76 ± 8 mmHg (P = 0.048). Although phenylephrine infusion returned MAP to normothermic levels (88 ± 7 mmHg; P > 0.999), sweat rate remained unchanged during phenylephrine infusion (1.39 ± 0.22 vs. 1.41 ± 0.24 mg·cm(-2)·min(-1); P > 0.999). These data indicate that both cardiopulmonary and arterial baroreceptor unloading do not limit increases in sweat rate during passive heat stress.

  19. Baroreceptor unloading does not limit forearm sweat rate during severe passive heat stress

    PubMed Central

    Schlader, Zachary J.; Gagnon, Daniel; Lucas, Rebekah A. I.; Pearson, James

    2014-01-01

    This study tested the hypothesis that sweat rate during passive heat stress is limited by baroreceptor unloading associated with heat stress. Two protocols were performed in which healthy subjects underwent passive heat stress that elicited an increase in intestinal temperature of ∼1.8°C. Upon attaining this level of hyperthermia, in protocol 1 (n = 10, 3 females) a bolus (19 ml/kg) of warm (∼38°C) isotonic saline was rapidly (5–10 min) infused intravenously to elevate central venous pressure (CVP), while in protocol 2 (n = 11, 5 females) phenylephrine was infused intravenously (60–120 μg/min) to return mean arterial pressure (MAP) to normothermic levels. In protocol 1, heat stress reduced CVP from 3.9 ± 1.9 mmHg (normothermia) to −0.6 ± 1.4 mmHg (P < 0.001), while saline infusion returned CVP to normothermic levels (5.1 ± 1.7 mmHg; P > 0.999). Sweat rate was elevated by heat stress (1.21 ± 0.44 mg·cm−2·min−1) but remained unchanged during rapid saline infusion (1.26 ± 0.47 mg·cm−2·min−1, P = 0.5), whereas cutaneous vascular conductance increased from 77 ± 10 to 101 ± 20% of local heating max (P = 0.029). In protocol 2, MAP was reduced with heat stress from 85 ± 7 mmHg to 76 ± 8 mmHg (P = 0.048). Although phenylephrine infusion returned MAP to normothermic levels (88 ± 7 mmHg; P > 0.999), sweat rate remained unchanged during phenylephrine infusion (1.39 ± 0.22 vs. 1.41 ± 0.24 mg·cm−2·min−1; P > 0.999). These data indicate that both cardiopulmonary and arterial baroreceptor unloading do not limit increases in sweat rate during passive heat stress. PMID:25525210

  20. Receding horizon controller for the baroreceptor loop in a model for the cardiovascular system.

    PubMed

    Mutsaers, Mark; Bachar, Mostafa; Batzel, Jerry; Kappel, Franz; Volkwein, Stefan

    2008-03-01

    In this article, we discuss the design and implementation of a receding horizon control (RHC) which will be used to represent the control for the baroreceptor loop in the human cardiovascular system (CVS). This control will be applied to a model of the CVS developed in a previous work by Kappel and Peer. In that earlier work, a linear quadratic control strategy (LQR) was implemented to represent this baroreflex control which was designed to stabilize the system under an ergometric workload. The RHC approach will be examined as an alternate to the LQR implementation. The control parameters in the cost functional of the RHC will be estimated using the same experimental data as was used in the LQR study. The results of the RHQ implementation will be compared with the LQR implementation.

  1. Forearm and Hand Function after Radial Artery Harvest for Coronary Artery Bypass Grafting: Subjective Patients' Assessment.

    PubMed

    Drohomirecka, Anna; Kwinecki, Paweł; Gwóźdź, Witold; Mieczyński, Mariusz; Stępiński, Piotr; Jasiński, Jarosław; Stręk, Krzysztof; Cichoń, Romulad

    2016-08-23

    As arterial myocardial revascularization is proved to provide great results, radial artery use as a graft and its consequences remain an important issue. The aim of the study was to evaluate how patients assess their forearm and hand function after radial artery harvest for coronary artery bypass grafting (CABG). 50 patients (mean age 52.2 ± 7.4 years) who underwent CABG at least 6 months (median follow up 11.75 months) earlier filled in a questionnaire concerning hand and forearm efficiency and discomfort. The global efficiency of the operated upper extremity was scored mean 8.87 ± 1.26 points on a 10-point scale and it was worse in patients who noticed at least one sort of disorder than in patients with no problems (8.6 ± 1.4 versus 9.4 ± 0.7 points; P = .04). Paresthesias were the most often reported disorders; 21 patients felt some tingling and/or numbness, but in only 14 (28%) could the symptoms be considered as related to the operation. 20 patients (40%) declared that they felt some scar-related discomfort. Reduced grip strength and excessive hand fatigue were reported by 20% and 10% of patients, respectively. None of those interviewed answered that symptoms reported affected his or her life activity on any level. The hand and forearm efficiency after radial artery harvest for CABG was highly evaluated by the majority of patients. Despite the fact that many patients reported some surgery-related problems, they did not notice extremity dysfunction that could limit their life activity.

  2. Effects of head-up tilting on baroreceptor control in subjects with different tolerances to orthostatic stress.

    PubMed

    Cooper, V L; Hainsworth, R

    2002-09-01

    During orthostatic stress, an increase in peripheral vascular resistance normally results in arterial blood pressure being well maintained, despite a decrease in cardiac output. The present study was undertaken to determine whether the sensitivity of the carotid baroreceptor reflex was increased during orthostatic stress and whether failure to develop this increase was associated with poor orthostatic tolerance. Three groups of subjects were studied: asymptomatic controls; patients investigated for suspected posturally related syncope but who had normal responses to an orthostatic stress test (normal patients); and patients who were shown to have low orthostatic tolerance (early fainters). We determined responses of R-R interval and forearm vascular resistance (mean arterial pressure/brachial artery velocity by Doppler ultrasonography) to the loading and unloading of carotid baroreceptors by application of pressures of -30 and +30 mmHg to a chamber fitted over the neck. Responses were determined after 20 min of supine rest and after 10 min of head-up tilt at 60 degrees. Responses of cardiac interval were not significantly different between the three groups, and they were not altered by the postural change. Vascular responses also did not differ between the groups during supine rest. However, in healthy volunteers and in normal patients, responses to both neck suction and pressure were significantly enhanced during head-up tilt. In controls, responses to suction were increased by tilt from 0.04+/-0.1 to -1.01+/-0.2%.mmHg(-1) (means+/-S.E.M.; P<0.001) and those to neck pressure from -0.6+/-0.3 to -3.1+/-1.1%.mmHg(-1) (P<0.05). In the normal patients, the corresponding changes were: during suction, from -0.2+/-0.1 to -0.7+/-0.1%.mmHg(-1) (P<0.05); during pressure, from -0.7+/-0.1 to -1.5+/-0.3%.mmHg(-1) (P<0.05). In contrast, in patients with low orthostatic tolerance, posture had no effect on the reflex (neck suction, from -0.3+/-0.1 to -0.3+/-0.1%.mmHg(-1); neck

  3. [Lung function testing in patients with pulmonary arterial hypertension].

    PubMed

    Escribano, P Martín; Sánchez, M A Gómez; de Atauri, M J Díaz; Frade, J Palomera; García, I Martín

    2005-07-01

    The main objective was to describe the results of lung function testing in a series of 120 patients with pulmonary arterial hypertension, and the secondary objective was to compare these findings with hemodynamic variables. This was a descriptive study of lung function in 120 patients with stable pulmonary arterial hypertension (Evian/Venice groups 1 and 4) studied until January 2002 in the Pulmonary Hypertension and Lung Transplant Working Group attached to the Cardiology Department of the Hospital Universtario 12 de Octubre in Madrid, Spain. Data were collected retrospectively for the first 47 patients (1981 to 1995) and prospectively thereafter for the remaining 73 patients. The diagnosis was idiopathic arterial hypertension or hypertension associated with collagenosis, chronic pulmonary embolism, cardiac shunt, or toxic oil syndrome (30 cases). In the group as a whole, forced vital capacity, forced expiratory volume in 1 second, and total lung capacity were normal; mean (SD) values revealed low carbon dioxide diffusing capacity (67.6% [23.2%]), and moderate hypoxemia (65.8 [15.4] mm Hg). No significant associations were observed between lung function and hemodynamic parameters. Mean age in the toxic oil syndrome group was lower (33.7 [11.4] years), and these patients had higher mean scores on the New York Heart Association scale (3.3 [0.5]) and for pulmonary vascular resistance (20.3 [8.1] kPa.L(-1).s). Lung function was studied in a series of 120 patients with pulmonary arterial hypertension (Evian/ Venice groups 1 and 4), 30 of whom had toxic oil syndrome. No significant associations were found between lung function and hemodynamic parameters.

  4. Pulmonary Function and Arterial Stiffness in Chronic Heart Failure

    PubMed Central

    Hu, Bangchuan; Gong, Shijin; Yu, Yihua; Dai, Haiwen

    2016-01-01

    Arterial stiffness contributes to heart failure and is decreased by angiotensin receptor blockers (ARBs). This cross-sectional study aimed to assess associations of lung function and ARB with arterial stiffness in patients with chronic heart failure. 354 outpatients (168 males; 186 females; 68.2 ± 7.2 years old) with chronic heart failure were evaluated. Lung function parameters, including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and FEV1 to FVC ratio (FEV1/FVC), were assessed. The cardio-ankle vascular index (CAVI) was used to estimate arterial stiffness. Unadjusted correlation analyses revealed a positive association of CAVI with ARB but not ACEI, and a negative correlation with FEV1 (r = −0.2987, p < 0.0001). Multiple stepwise regression analyses showed that ARB and FEV1 (p < 0.0001) were independent predicting factors for CAVI. These findings suggest that reduced pulmonary function is associated with increased CAVI. Pulmonary function protection could be used to improve the prognosis in heart failure, but additional studies are necessary. PMID:28097138

  5. Greater impairments in cerebral artery compared with skeletal muscle feed artery endothelial function in a mouse model of increased large artery stiffness

    PubMed Central

    Walker, Ashley E; Henson, Grant D; Reihl, Kelly D; Morgan, R Garrett; Dobson, Parker S; Nielson, Elizabeth I; Ling, Jing; Mecham, Robert P; Li, Dean Y; Lesniewski, Lisa A; Donato, Anthony J

    2015-01-01

    Advancing age as well as diseases such as diabetes are characterized by both increased large artery stiffness and impaired peripheral artery function. It has been hypothesized that greater large artery stiffness causes peripheral artery dysfunction; however, a cause-and-effect relationship has not previously been established. We used elastin heterozygote mice (Eln+/–) as a model of increased large artery stiffness without co-morbidities unrelated to the large artery properties. Aortic stiffness, measured by pulse wave velocity, was ∼35% greater in Eln+/– mice than in wild-type (Eln+/+) mice (P = 0.04). Endothelium-dependent dilatation (EDD), assessed by the maximal dilatation to acetylcholine, was ∼40% lower in Eln+/– than Eln+/+ mice in the middle cerebral artery (MCA, P < 0.001), but was similar between groups in the gastrocnemius feed arteries (GFA, P = 0.79). In the MCA, EDD did not differ between groups after incubation with the nitric oxide (NO) synthase inhibitor Nω-nitro-l-arginine methyl ester (P > 0.05), indicating that lower NO bioavailability contributed to the impaired EDD in Eln+/– mice. Superoxide production and content of the oxidative stress marker nitrotyrosine was higher in MCAs from Eln+/− compared with Eln+/+ mice (P < 0.05). In the MCA, after incubation with the superoxide scavenger TEMPOL, maximal EDD improved by ∼65% in Eln+/– (P = 0.002), but was unchanged in Eln+/+ mice (P = 0.17). These results indicate that greater large artery stiffness has a more profound effect on endothelial function in cerebral arteries compared with skeletal muscle feed arteries. Greater large artery stiffness can cause cerebral artery endothelial dysfunction by reducing NO bioavailability and increasing oxidative stress. PMID:25627876

  6. Carotid baroreceptor stimulation alters cutaneous vascular conductance during whole-body heating in humans

    PubMed Central

    Keller, David M; Davis, Scott L; Low, David A; Shibasaki, Manabu; Raven, Peter B; Crandall, Craig G

    2006-01-01

    Prior studies investigating carotid baroreflex control of the cutaneous vasculature have yielded mixed findings. However, previously used methodological and analytical techniques may limit the ability to detect carotid baroreflex-mediated changes in cutaneous vascular conductance (CVC). The aim of this study was to test the hypothesis that dynamic carotid baroreceptor stimulation (i.e. 5 s trials) using neck pressure (NP, simulated carotid hypotension) and neck suction (NS, simulated carotid hypertension) will decrease and increase CVC, respectively, during normothermic and whole-body heating conditions in resting humans. Data were obtained from nine subjects (age, 31 ± 2 year). The ratio of forearm skin blood flux (laser-Doppler flowmetry) and arterial blood pressure (Finapres) was used as an index of CVC. Multiple 5 s trials of NP (+40Torr) and NS (−60Torr), as well as breath-hold/airflow control trials, were applied during end-expiratory breath-holds while subjects were normotheric and heat stressed (change in core temperature ∼0.75°C). CVC responses to each NP and NS trial were averaged into 1 s intervals during the following periods: 3 s prestimulus, 5 s during stimulus, and 5 s poststimulus. Peak CVC responses (3 s average) to NP and NS were compared to prestimulus values using paired t test. During normothermia, NP decreased CVC by 0.032 ± 0.007 arbitrary units (a.u.) mmHg−1; (P < 0.05); however, breath-hold/airflow control trials resulted in similar decreases in CVC. NS did not change CVC (Δ = 0.002 ± 0.005 a.u. mmHg−1; P = 0.63). During whole-body heating, NP decreased CVC (by 0.16 ± 0.04 a.u. mmHg−1; (P < 0.05), whereas NS increased CVC by 0.07 ± 0.03 a.u. mmHg−1; (P < 0.05). Furthermore, these changes were greater than, or directionally different from, the breath-hold/airflow control trials. These findings indicate that carotid baroreceptor stimulation elicits dynamic changes in CVC and that these changes are more apparent during whole

  7. Discharges of aortic and carotid sinus baroreceptors during spontaneous motor activity and pharmacologically evoked pressor interventions.

    PubMed

    Matsukawa, Kanji; Ishii, Kei; Kadowaki, Akito; Ishida, Tomoko; Idesako, Mitsuhiro; Liang, Nan

    2014-07-01

    Our laboratory has demonstrated that the cardiomotor component of aortic baroreflex is temporarily inhibited at the onset of spontaneous motor activity in decerebrate cats, without altering carotid sinus baroreflex. A reason for this dissociation may be attributed to a difference in the responses between aortic nerve activity (AoNA) and carotid sinus nerve activity (CsNA) during spontaneous motor activity. The stimulus-response curves of AoNA and CsNA against mean arterial blood pressure (MAP) were compared between the pressor interventions evoked by spontaneous motor activity and by intravenous administration of phenylephrine or norepinephrine, in which the responses in heart rate (HR) were opposite (i.e., tachycardia vs. baroreflex bradycardia), despite the identical increase in MAP of 34-40 mmHg. In parallel to the pressor response, mean AoNA and CsNA increased similarly by 78-81 and by 88 % of the baseline control, respectively, irrespective of whether the pressor response was evoked by spontaneous motor activity or by a pharmacological intervention. The slope of the stimulus-response curve of the mean AoNA became greater (P < 0.05) during spontaneous motor activity as compared to the pharmacological intervention. On the other hand, the stimulus-response curve of the mean CsNA and its slope were equal (P > 0.05) between the two pressor interventions. Furthermore, the slopes of the stimulus-response curves of both diastolic AoNA and CsNA (defined as the minimal value within a beat) exhibited a greater increase during spontaneous motor activity. All differences in the slopes of the stimulus-response curves were abolished by restraining HR at the intrinsic cardiac frequency. In conclusion, mean mass activities of both aortic and carotid sinus baroreceptors are able to encode the beat-by-beat changes in MAP not only at rest but also during spontaneous motor activity and spontaneous motor activity-related reduction of aortic baroreceptor activity is denied

  8. Relation of left ventricular midwall function to cardiovascular risk factors and arterial structure and function.

    PubMed

    Devereux, R B; de Simone, G; Pickering, T G; Schwartz, J E; Roman, M J

    1998-04-01

    Left ventricular (LV) midwall shortening (MWS) is subnormal in relation to LV circumferential end-systolic stress (ESS) (ESS-corrected MWS) in many hypertensive patients with normal LV chamber function and predicts subsequent morbidity and mortality. However, little is known of the relations of LV midwall function to demographic and metabolic variables or to arterial geometry. Asymptomatic, unmedicated normotensive (n=366) or hypertensive (n=282) adults were assessed with echocardiography and carotid ultrasound. In normal adults, lower LV MWS and ESS-corrected MWS, an index of LV contractility, were related independently to high total peripheral resistance, high heart rate, and male gender (all P<.00001), lower serum HDL cholesterol (P=.001) and diastolic pressure (P=.003), and for ESS-corrected MWS only, arterial relative wall thickness (RWT, P=.03). Among hypertensive patients, lower values for both midwall function indices were associated independently with higher peripheral resistance (P<.00001), heart rate (P<.00005), body mass index (P<.01), and arterial RWT (P=.04), as well as male gender (P<.0002). In the entire population, lower LV MWS was independently related to higher peripheral resistance, heart rate (both P<.00001), body mass index (P=.0006) and arterial RWT (P=.009); male gender (P<.00001); and lower age (P=.004), diastolic pressure (P=.042), and systolic carotid artery expansion (P=.032). Lower ESS-corrected MWS in the entire population was independently associated with higher peripheral resistance and heart rate (both P<.00001), body mass index (P=.0006), arterial RWT (P=.004); male gender; and lower diastolic pressure (both P<.00001), age (P<.00005), arterial expansion in systole (P=.006), and serum HDL cholesterol levels (P=.04). Among a subset (n=60), ESS-corrected MWS was positively related to apolipoprotein A1 (P=.004) and negatively to hemoglobin A1c (P<.01). Thus, higher LV midwall function is associated with female gender and more favorable

  9. Pontomedullary transection attenuates central respiratory modulation of sympathetic discharge, heart rate and the baroreceptor reflex in the in situ rat preparation.

    PubMed

    Baekey, David M; Dick, Thomas E; Paton, Julian F R

    2008-07-01

    Previous studies have indicated a major role for the pons in the genesis of the respiratory pattern. The respiratory rhythm is coupled to the cardiovascular system to ensure optimal matching of minute ventilation and cardiac output. Since much of this coupling results from cross-talk between brainstem circuits, we have assessed the role of the pons in both the co-ordination of respiratory and cardiovascular efferent activities and the baroreceptor reflex efficacy. Using the arterially perfused in situ rat preparation, we recorded neural activities from the left phrenic nerve, central end of the vagus nerve, thoracic sympathetic chain (T8-T10) and heart rate. Respiratory sinus arrhythmia, respiratory modulation of sympathetic nerve activity (and Traube-Hering waves in arterial pressure) and postinspiratory discharges recorded from vagal efferents were eliminated after pontine transection. We also found that although the sympathetic arterial baroreflex remained intact, respiratory gating of the baroreceptor reflex (i.e. both bradycardia and sympathoinhibition) was abolished after pontine removal. We propose that neural activity of the pons is essential for physiological coupling of centrally generated respiratory and cardiovascular efferent activities.

  10. Effect of dark chocolate on arterial function in healthy individuals.

    PubMed

    Vlachopoulos, Charalambos; Aznaouridis, Konstantinos; Alexopoulos, Nikolaos; Economou, Emmanuel; Andreadou, Ioanna; Stefanadis, Christodoulos

    2005-06-01

    Epidemiologic studies suggest that high flavonoid intake confers a benefit on cardiovascular outcome. Endothelial function, arterial stiffness, and wave reflections are important determinants of cardiovascular performance and are predictors of cardiovascular risk. The effect of flavonoid-rich dark chocolate (100 g) on endothelial function, aortic stiffness, wave reflections, and oxidant status were studied for 3 h in 17 young healthy volunteers according to a randomized, single-blind, sham procedure-controlled, cross-over protocol. Flow-mediated dilation (FMD) of the brachial artery, aortic augmentation index (AIx), and carotid-femoral pulse wave velocity (PWV) were used as measures of endothelial function, wave reflections, and aortic stiffness, respectively. Plasma oxidant status was evaluated with measurement of plasma malondialdehyde (MDA) and total antioxidant capacity (TAC). Chocolate led to a significant increase in resting and hyperemic brachial artery diameter throughout the study (maximum increase by 0.15 mm and 0.18 mm, respectively, P < .001 for both). The FMD increased significantly at 60 min (absolute increase 1.43%, P < .05). The AIx was significantly decreased with chocolate throughout the study (maximum absolute decrease 7.8%, P < .001), indicating a decrease in wave reflections, whereas PWV did not change to a significant extent. Plasma MDA and TAC did not change after chocolate, indicating no alterations in plasma oxidant status. Our study shows for the first time that consumption of dark chocolate acutely decreases wave reflections, that it does not affect aortic stiffness, and that it may exert a beneficial effect on endothelial function in healthy adults. Chocolate consumption may exert a protective effect on the cardiovascular system; further studies are warranted to assess any long-term effects.

  11. Acute presentations of renal artery stenosis in three patients with a solitary functioning kidney.

    PubMed

    Pun, E; Dowling, R J; Mitchell, P J

    2004-12-01

    Renal artery stenosis can present uncommonly in the acute state as flash pulmonary oedema and hypertensive encephalopathy. We present three such cases in patients with a solitary functioning kidney, with successful management via renal artery angioplasty and stent insertion.

  12. TRPC5 channels participate in pressure-sensing in aortic baroreceptors

    PubMed Central

    Lau, On-Chai; Shen, Bing; Wong, Ching-On; Tjong, Yung-Wui; Lo, Chun-Yin; Wang, Hui-Chuan; Huang, Yu; Yung, Wing-Ho; Chen, Yang-Chao; Fung, Man-Lung; Rudd, John Anthony; Yao, Xiaoqiang

    2016-01-01

    Blood pressure is maintained within a normal physiological range by a sophisticated regulatory mechanism. Baroreceptors serve as a frontline sensor to detect the change in blood pressure. Nerve signals are then sent to the cardiovascular control centre in the brain in order to stimulate baroreflex responses. Here, we identify TRPC5 channels as a mechanical sensor in aortic baroreceptors. In Trpc5 knockout mice, the pressure-induced action potential firings in the afferent nerve and the baroreflex-mediated heart rate reduction are attenuated. Telemetric measurements of blood pressure demonstrate that Trpc5 knockout mice display severe daily blood pressure fluctuation. Our results suggest that TRPC5 channels represent a key pressure transducer in the baroreceptors and play an important role in maintaining blood pressure stability. Because baroreceptor dysfunction contributes to a variety of cardiovascular diseases including hypertension, heart failure and myocardial infarction, our findings may have important future clinical implications. PMID:27411851

  13. Arterial structure and function and environmental exposure to cadmium.

    PubMed

    Schutte, R; Nawrot, T; Richart, T; Thijs, L; Roels, H A; Van Bortel, L M; Struijker-Boudier, H; Staessen, J A

    2008-06-01

    Few studies have addressed the effect of cadmium toxicity on arterial properties. We investigated the possible association of 24 h urinary cadmium excretion (an index of lifetime exposure) with measures of arterial function in a randomly selected population sample (n = 557) from two rural areas with low and high environmental exposure to cadmium. 24 h urinary cadmium excretion was significantly higher in the high compared with the low exposure group (p<0.001). Even though systolic (p = 0.42), diastolic (p = 0.14) and mean arterial pressure (p = 0.68) did not differ between the high and low exposure groups, aortic pulse wave velocity (p = 0.008), brachial pulse pressure (p = 0.026) and femoral pulse pressure (p = 0.008) were significantly lower in the high exposure group. Additionally, femoral distensibility (p<0.001) and compliance (p = 0.001) were significantly higher with high exposure. Across quartiles of 24 h urinary cadmium excretion (adjusted for sex and age), brachial (p for trend = 0.015) and femoral (p for trend = 0.018) pulse pressure significantly decreased and femoral distensibility (p for trend = 0.008) and compliance (p for trend = 0.007) significantly increased with higher cadmium excretion. After full adjustment, the partial regression coefficients confirmed these associations. Pulse wave velocity (beta = -0.79+/-0.27; p = 0.004) and carotid (beta = -4.20+/-1.51; p = 0.006), brachial (beta = -5.43+/-1.41; p = 0.001) and femoral (beta = -4.72+/-1.74; p = 0.007) pulse pressures correlated negatively, whereas femoral compliance (beta = 0.11+/-0.05; p = 0.016) and distensibility (beta = 1.70+/-0.70; p = 0.014) correlated positively with cadmium excretion. Increased cadmium body burden is associated with lower aortic pulse wave velocity, lower pulse pressure throughout the arterial system, and higher femoral distensibility.

  14. Trans-arterial Onyx Embolization of a Functional Thoracic Paraganglioma

    PubMed Central

    Chacón-Quesada, Tatiana; Maud, Alberto; Ramos-Duran, Luis; Torabi, Alireza; Fitzgerald, Tamara; Akle, Nassim; Cruz Flores, Salvador; Trier, Todd

    2015-01-01

    Paragangliomas are rare tumors of the endocrine system. They are highly vascular and in some cases hormonally active, making their management challenging. Although there is strong evidence of the safety and effectiveness of preoperative embolization in the management of spinal tumors, only five cases have been reported in the setting of thoracic paragangliomas. We present the case of a 19-year-old man with a large, primary, functional, malignant paraganglioma of the thoracic spine causing a vertebral fracture and spinal cord compression. To our knowledge this is the first report of preoperative trans-arterial balloon augmented Onyx embolization of a thoracic paraganglioma. PMID:25763296

  15. [Effect of intracerebroventricular injection of histamine on carotid sinus baroreceptor reflex in anesthetized rats and its mechanism].

    PubMed

    Wang, Guo-Qing; Zhou, Xi-Ping; Huang, Wei-Qiu

    2002-12-25

    The changes in carotid sinus baroreceptor reflex (CSR) performance induced by intracerebroventricular injection (i.c.v.) of histamine (HA) were investigated. The effects of pretreatment with HA receptors antagonists into the cerebroventricle or nucleus of solitary tract (NTS) on the responses of CSR to HA were also examined. Intracarotid sinus pressure (ISP)-mean arterial pressure (MAP) relationship curve was constructed by fitting to the logistic function with five parameters in 50 Wistar rats anesthetized with pentobarbital sodium. The left and right carotid sinus regions were isolated from the systemic circulation and the ISP was altered in a stepwise manner. The main results obtained are as follows. (1) i.c.v. injection of HA (100 ng) significantly shifted the ISP-MAP relationship curve upwards and moved the middle part of ISP-Gain relationship curve downwards, and reduced the MAP range and maximum gain (G(max)), but increased the threshold pressure (TP), saturation pressure (SP) and ISP at G(max) (ISP (Gmax)). (2) The pretreatment with H(1) or H(2) receptors antagonist, chlorpheniramine (CHL, 5 microg) or cimetidine (CIM, 15 microg), could obviously diminish the above-mentioned changes in CSR performance induced by HA, but the effect of CIM was less remarkable than that of CHL. (3) The pretreatment with both CHL and CIM (5 microg and 15 microg) at the same time abolished the responses of CSR performance to HA completely. (4) After microinjection of CHL (0.5 microg) or CIM (1.5 microg) into the NTS, the responses of CSR to HA were similar to those after i.c.v. CHL or CIM, but the change in TP was significantly decreased. These findings suggest that the intracerebroventricular administration of HA results in a rapid resetting of CSR and a decrease in reflex sensitivity. The response of CSR to HA might be mediated by both central H(1) and H(2) receptors, especially by H(1) receptors. The effects of the central HA on CSR might be related to a histaminergic

  16. Blood pressure and mesenteric resistance arterial function after spaceflight

    NASA Technical Reports Server (NTRS)

    Hatton, Daniel C.; Yue, Qi; Chapman, Justin; Xue, Hong; Dierickx, Jacqueline; Roullet, Chantal; Coste, Sarah; Roullet, Jean Baptiste; McCarron, David A.

    2002-01-01

    Ground studies indicate that spaceflight may diminish vascular contraction. To examine that possibility, vascular function was measured in spontaneously hypertensive rats immediately after an 18-day shuttle flight. Isolated mesenteric resistance arterial responses to cumulative additions of norepinephrine, acetylcholine, and sodium nitroprusside were measured using wire myography within 17 h of landing. After flight, maximal contraction to norepinephrine was attenuated (P < 0.001) as was relaxation to acetylcholine (P < 0.001) and sodium nitroprusside (P < 0.05). At high concentrations, acetylcholine caused vascular contraction in vessels from flight animals but not in vessels from vivarium control animals (P < 0.05). The results are consistent with data from ground studies and indicate that spaceflight causes both endothelial-dependent and endothelial-independent alterations in vascular function. The resulting decrement in vascular function may contribute to orthostatic intolerance after spaceflight.

  17. Blood pressure and mesenteric resistance arterial function after spaceflight

    NASA Technical Reports Server (NTRS)

    Hatton, Daniel C.; Yue, Qi; Chapman, Justin; Xue, Hong; Dierickx, Jacqueline; Roullet, Chantal; Coste, Sarah; Roullet, Jean Baptiste; McCarron, David A.

    2002-01-01

    Ground studies indicate that spaceflight may diminish vascular contraction. To examine that possibility, vascular function was measured in spontaneously hypertensive rats immediately after an 18-day shuttle flight. Isolated mesenteric resistance arterial responses to cumulative additions of norepinephrine, acetylcholine, and sodium nitroprusside were measured using wire myography within 17 h of landing. After flight, maximal contraction to norepinephrine was attenuated (P < 0.001) as was relaxation to acetylcholine (P < 0.001) and sodium nitroprusside (P < 0.05). At high concentrations, acetylcholine caused vascular contraction in vessels from flight animals but not in vessels from vivarium control animals (P < 0.05). The results are consistent with data from ground studies and indicate that spaceflight causes both endothelial-dependent and endothelial-independent alterations in vascular function. The resulting decrement in vascular function may contribute to orthostatic intolerance after spaceflight.

  18. [Effects of weightlessness on baroreflex function].

    PubMed

    Shen, Xian-yun

    2002-12-01

    The declination of baroreceptor reflex function is one of the important factor causing orthostatic intolerance after space flight. The change of baroreceptor reflex function during weightlessness and simulated weightlessness is introduced, and the influence of elevatory upper body blood pressure and electrolyte changes caused by weightlessness on baroreflex function are analyzed.

  19. Obesity, arterial function and arterial structure - a systematic review and meta-analysis.

    PubMed

    Ne, J Y A; Cai, T Y; Celermajer, D S; Caterson, I D; Gill, T; Lee, C M Y; Skilton, M R

    2017-06-01

    Obesity is an established risk factor for cardiovascular disease. The mechanisms by which obesity affects cardiovascular risk have not been fully elucidated. This paper reports a comprehensive systematic review and meta-analysis on obesity and two key aspects of vascular health using gold-standard non-invasive measures - arterial endothelial function (brachial flow-mediated dilatation) and subclinical atherosclerosis (carotid intima-media thickness). Electronic searches for 'Obesity and flow-mediated dilatation' and 'Obesity and intima-media thickness' were performed using Ovid Medline and Embase databases. A meta-analysis was undertaken for brachial flow-mediated dilatation and carotid intima-media thickness to obtain pooled estimates for adults with obesity and those with healthy weight. Of the 5,810 articles retrieved, 19 studies on flow-mediated dilatation and 19 studies on intima-media thickness were included. Meta-analysis demonstrated that obesity was associated with lower flow-mediated dilatation (-1.92 % [95% CI -2.92, -0.92], P = 0.0002) and greater carotid intima-media thickness (0.07 mm [95% CI 0.05, 0.08], P < 0.0001). Obesity is associated with poorer arterial endothelial function and increased subclinical atherosclerosis, consistent with these aspects of vascular health at least partially contributing to the increased risk of cardiovascular events in adults with obesity. These estimated effect sizes will enable vascular health benefits in response to weight loss treatment to be put in greater perspective, both in the research setting and potentially also clinical practice.

  20. Transcutaneous measurement of the arterial input function in positron emission tomography

    SciTech Connect

    Litton, J.E.; Eriksson, L. )

    1990-04-01

    Positron emission tomography (PET) provides a powerful tool in medical research. Biochemical function can be both precisely localized and quantitatively measured. To achieve reliable quantitation it is necessary to know the time course of activity concentration in the arterial blood during the measurement. In this study the arterial blood curve from the brachial artery is compared to the activity measured in the internal carotid artery with a new transcutaneous detector.

  1. Deterioration in Renal Function Is Associated With Increased Arterial Stiffness

    PubMed Central

    2014-01-01

    BACKGROUND Higher levels of baseline pulse wave velocity (PWV) have been associated with longitudinal decline in renal function in patients with kidney disease. We examined longitudinal decline in renal function in relation to levels of PWV. We hypothesized that longitudinal decline in renal function in a community-based, nonclinic sample would be associated with higher levels of PWV. METHODS We conducted a 4–5 year longitudinal study with 482 community-living individuals free from acute stroke, dementia, and end-stage renal disease (mean age = 60.9 years; 59% women; 93.2% white; 10% with diabetes mellitus; mean estimated glomerular filtration rate (eGFR) = 79.2ml/min/1.73 m2). Multiple linear regression analyses were used to examine the association between changes in renal function (eGFR and serum creatinine) from baseline to follow-up and PWV levels at follow-up, the outcome measure. Regression coefficients were adjusted for age, sex, education, race/ethnicity, weight, activity level, mean arterial pressure, treatment of hypertension, and cardiovascular risk factors. RESULTS With adjustment for covariables, decline in renal function was associated with higher levels of PWV over a mean follow-up of 4.68 years. CONCLUSIONS Decline in renal functioning from baseline levels measured 4–5 years before measurement of PWV is related to higher levels of PWV in a community sample. PMID:24080989

  2. Influence of physical exercise on baroreceptor sensitivity during pregnancy.

    PubMed

    Carpenter, R E; Emery, S J; Uzun, O; Rassi, D; Lewis, M J

    2017-03-01

    Baroreceptor sensitivity (BRS) refers to the magnitude of change in the heart rate in response to change in blood pressure (e.g. upon standing). The impact of regular antenatal exercise on maternal BRS is unclear. To determine whether supervised weekly exercise influences BRS, and to determine if posture and calculation method are important in antenatal BRS measurement. Eighty-one healthy pregnant women were randomly assigned to an exercise or control group. The exercise group attended weekly classes from the 20th week of pregnancy onwards. Cardiovascular assessments (beat-to-beat blood pressure, heart rate) were performed at 12-16, 26-28, 34-36 weeks and 12 weeks following birth. BRS was calculated using two methods ("sequence" and "beat-to-beat"). Fifty-one women (63%) completed the study. Mean BRS reduced progressively in all women (p < 0.025) and was lowest in those who exercised (0.046 < p < 0.002). Postnatal increases in BRS were independent of posture. Training-induced BRS (beat-to-beat) reduction occurred earlier than BRS (sequence), and only BRS (sequence) was affected by posture. Heart rate variability reduced with advancing gestation (p < 0.002) and was more pronounced in the exercise group (p < 0.029). Weekly exercise exaggerated the reductions in BRS and HRV during pregnancy and is likely linked to diminished parasympathetic activity.

  3. Autocrine/paracrine modulation of baroreceptor activity after antidromic stimulation of aortic depressor nerve in vivo.

    PubMed

    Santana-Filho, Valter J; Davis, Greg J; Castania, Jaci A; Ma, Xiuying; Salgado, Helio C; Abboud, Francois M; Fazan, Rubens; Chapleau, Mark W

    2014-02-01

    Activation of the sensory nerve endings of non-myelinated C-fiber afferents evokes release of autocrine/paracrine factors that cause localized vasodilation, neurogenic inflammation, and modulation of sensory nerve activity. The aims of this study were to determine the effect of antidromic electrical stimulation on afferent baroreceptor activity in vivo, and investigate the role of endogenous prostanoids and hydrogen peroxide (H2O2) in mediating changes in nerve activity. Baroreceptor activity was recorded from the left aortic depressor nerve (ADN) in anesthetized rats before and after stimulating the ADN for brief (5–20 s) periods. The rostral end of the ADN was crushed or sectioned beforehand to prevent reflex changes in blood pressure. Antidromic stimulation of ADN using parameters that activate both myelinated A-fibers and non-myelinated C-fibers caused pronounced and long-lasting (> 1 min) inhibition of baroreceptor activity (n = 9, P < 0.05), with the magnitude and duration of inhibition dependent on the duration of the stimulation period (n = 5). Baroreceptor activity was only transiently inhibited after selective stimulation of A-fibers. The inhibition of activity after antidromic stimulation of A and C fibers was prolonged after administration of the cyclooxygenase inhibitor indomethacin (5 mg/kg, IV, n = 7) and abolished after administration of PEG-catalase (104 units/kg, IV, n = 7), an enzyme that catalyzes the decomposition of H2O2 to water and oxygen. The results demonstrate a long-lasting inhibition of baroreceptor activity after antidromic stimulation of ADN and suggest that endogenous prostanoids and H2O2 oppose and mediate the inhibition, respectively. These mechanisms may contribute to rapid baroreceptor resetting during acute hypertension and be engaged during chronic baroreceptor activation therapy in patients with hypertension.

  4. Impaired arterial smooth muscle cell vasodilatory function in methamphetamine users.

    PubMed

    Nabaei, Ghaemeh; Oveisgharan, Shahram; Ghorbani, Askar; Fatehi, Farzad

    2016-11-15

    Methamphetamine use is a strong risk factor for stroke. This study was designed to evaluate arterial function and structure in methamphetamine users ultrasonographically. In a cross-sectional study, 20 methamphetamine users and 21 controls, aged between 20 and 40years, were enrolled. Common carotid artery intima-media thickness (CCA-IMT) marker of early atherogenesis, flow-mediated dilatation (FMD) determinants of endothelium-dependent vasodilation, and nitroglycerine-mediated dilatation (NMD) independent marker of vasodilation were measured in two groups. There were no significant differences between the two groups regarding demographic and metabolic characteristics. The mean (±SD) CCA-IMT in methamphetamine users was 0.58±0.09mm, versus 0.59±0.07mm in the controls (p=0.84). Likewise, FMD% was not significantly different between the two groups [7.6±6.1% in methamphetamine users vs. 8.2±5.1% in the controls; p=0.72], nor were peak flow and shear rate after hyperemia. However, NMD% was considerably decreased in the methamphetamine users [8.5±7.8% in methamphetamine users vs. 13.4±6.2% in controls; p=0.03]. According to our results, NMD is reduced among otherwise healthy methamphetamine users, which represents smooth muscle dysfunction in this group. This may contribute to the high risk of stroke among methamphetamine users. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Ovarian function after uterine artery embolization and hysterectomy.

    PubMed

    Healey, Sarah; Buzaglo, Karen; Seti, Laurent; Valenti, David; Tulandi, Togas

    2004-08-01

    To evaluate the effect of uterine artery embolization (UAE) and hysterectomy on ovarian function. Prospective case control study (Canadian Task Force classification II-2). University teaching hospital. Eighty-four healthy premenopausal women with symptomatic uterine myoma(s) undergoing UAE or hysterectomy. Patients had blood drawn to measure follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) levels and underwent transvaginal ultrasound to measure volume of the myoma(s) and uterus on cycle day 3 before the procedures. These measurements were repeated 3 and 6 months after treatment. The main outcome was the differences in serum FSH, LH, E2, and ultrasound findings before and after UAE or hysterectomy. Of the 68 patients who underwent UAE and 16 who underwent hysterectomy, 48 and 13 respectively, completed 6-month follow-up. The mean age of the patients in the UAE group was 44.9 +/- 3.8 years and 43.7 +/- 5.6 years in the hysterectomy group. There was no significant difference in serum FSH before (8.9 +/- 0.7 IU/L) and 6 months after UAE (9.9 +/- 1.0 lU/L), and between the baseline (10.4 +/- 1.8 lU/L) and 6 months posthysterectomy (7.8 +/- 1.8 lU/L). The uterine volume 6 months after UAE (361 +/- 50 mL) was significantly smaller than before UAE(538 +/- 38mL; p =.005, 95% CI 44-241). Compared with baseline (154 +/- 20 mL), the dominant myoma volume was smaller at 6 months after UAE (97 +/- 16 mL; p <.05, 95% CI 1.57-62). Uterine artery embolization is associated with a significant reduction in myoma and uterine volume. Ovarian function at 6 months, as indicated by day 3 FSH levels, is not affected by UAE or hysterectomy.

  6. Effect of baroreceptor stimulation on the respiratory pattern: Insights into respiratory-sympathetic interactions✰

    PubMed Central

    Baekey, David M.; Molkov, Yaroslav I.; Paton, Julian F.R.; Rybak, Ilya A.; Dick, Thomas E.

    2013-01-01

    Sympathetic nerve activity (SNA) is modulated by respiratory activity which indicates the existence of direct interactions between the respiratory and sympathetic networks within the brainstem. Our experimental studies reveal that TE prolongation evoked by baroreceptor stimulation varies with respiratory phase and depends on the pons. We speculate that the sympathetic baroreceptor reflex, providing negative feedback from baroreceptors to the rostral ventrolateral medulla and SNA, has two pathways: one direct and independent of the respiratory–sympathetic interactions and the other operating via the respiratory pattern generator and is hence dependent on the respiratory modulation of SNA. Our experimental studies in the perfused in situ rat preparation and complementary computational modelling studies support the hypothesis that baroreceptor activation during expiration prolongs the TE via transient activation of post-inspiratory and inhibition of augmenting expiratory neurones of the Bötzinger Complex (BötC). We propose that these BötC neurones are also involved in the respiratory modulation of SNA, and contribute to the respiratory modulation of the sympathetic baroreceptor reflex. PMID:20837166

  7. Vascular and baroreceptor abnormalities in young males with a family history of hypertension.

    PubMed

    Boutcher, Yati N; Park, Young J; Boutcher, Stephen H

    2009-12-01

    Vascular and baroreceptor abnormalities in 44 young males, mean age 21 years, comprising of offspring with (FH(+); n = 22) and without (FH(-); n = 22) hypertensive parents, were investigated. Peak forearm blood flow (FBF), which was defined as the highest blood flow obtained following reactive hyperaemia, was assessed using strain gauge plethysmography following 5 min of ischemia. Cardiopulmonary baroreceptor sensitivity was assessed using lower body negative pressure for 5 min at -20 mmHg and was determined by calculating change of stroke volume and forearm vascular resistance (FVR) to lower body negative pressure. Carotid baroreceptor sensitivity was assessed using neck suction at -20, -40, -60, and -80 mmHg and was calculated by dividing RR interval by systolic blood pressure. Augmentation index, a measure of wave reflection, was assessed using applanation tonometry and was calculated as the ratio of augmented pressure and pulse pressure. Peak FBF of FH(+) was 19% lower than the FH(-) (p = 0.02). Also FH(+) had 17% higher peak FVR compared to FH(-) (p = 0.04). However, there were no significant differences between groups for cardiopulmonary, carotid baroreceptor sensitivity, and augmentation index. These results suggest that peripheral vascular dysfunction appears earlier than abnormal baroreceptor sensitivity in young males with a family history of hypertension.

  8. Characterizing Resting-State Brain Function Using Arterial Spin Labeling

    PubMed Central

    Jann, Kay; Wang, Danny J.J.

    2015-01-01

    Abstract Arterial spin labeling (ASL) is an increasingly established magnetic resonance imaging (MRI) technique that is finding broader applications in studying the healthy and diseased brain. This review addresses the use of ASL to assess brain function in the resting state. Following a brief technical description, we discuss the use of ASL in the following main categories: (1) resting-state functional connectivity (FC) measurement: the use of ASL-based cerebral blood flow (CBF) measurements as an alternative to the blood oxygen level-dependent (BOLD) technique to assess resting-state FC; (2) the link between network CBF and FC measurements: the use of network CBF as a surrogate of the metabolic activity within corresponding networks; and (3) the study of resting-state dynamic CBF-BOLD coupling and cerebral metabolism: the use of dynamic CBF information obtained using ASL to assess dynamic CBF-BOLD coupling and oxidative metabolism in the resting state. In addition, we summarize some future challenges and interesting research directions for ASL, including slice-accelerated (multiband) imaging as well as the effects of motion and other physiological confounds on perfusion-based FC measurement. In summary, this work reviews the state-of-the-art of ASL and establishes it as an increasingly viable MRI technique with high translational value in studying resting-state brain function. PMID:26106930

  9. Evaluation of ventricular function in patients with coronary artery disease

    SciTech Connect

    Rocco, T.P.; Dilsizian, V.; Fischman, A.J.; Strauss, H.W.

    1989-07-01

    The recent expansion of interventional cardiovascular technologies has stimulated a concomitant expansion of noninvasive cardiac studies, both to assist in diagnosis and to evaluate treatment outcomes. Radionuclide ventricular function studies provide a reliable, reproducible means to quantify global left ventricular systolic performance, a critical determinant of prognosis in patients with cardiovascular disease. In addition, the ability to evaluate regional left ventricular wall motion and to assess ventricular performance during exercise have secured a fundamental role for such studies in the screening and treatment of patients with coronary artery disease. Radionuclide techniques have been extended to the evaluation of left ventricular relaxation/filling events, left ventricular systolic/diastolic function in the ambulatory setting, and with appropriate technical modifications, to the assessment of right ventricular performance at rest and with exercise. As a complement to radionuclide perfusion studies, cardiac blood-pool imaging allows for thorough noninvasive description of cardiac physiology and function in both normal subjects and in patients with a broad range of cardiovascular diseases. 122 references.

  10. Characterizing Resting-State Brain Function Using Arterial Spin Labeling.

    PubMed

    Chen, J Jean; Jann, Kay; Wang, Danny J J

    2015-11-01

    Arterial spin labeling (ASL) is an increasingly established magnetic resonance imaging (MRI) technique that is finding broader applications in studying the healthy and diseased brain. This review addresses the use of ASL to assess brain function in the resting state. Following a brief technical description, we discuss the use of ASL in the following main categories: (1) resting-state functional connectivity (FC) measurement: the use of ASL-based cerebral blood flow (CBF) measurements as an alternative to the blood oxygen level-dependent (BOLD) technique to assess resting-state FC; (2) the link between network CBF and FC measurements: the use of network CBF as a surrogate of the metabolic activity within corresponding networks; and (3) the study of resting-state dynamic CBF-BOLD coupling and cerebral metabolism: the use of dynamic CBF information obtained using ASL to assess dynamic CBF-BOLD coupling and oxidative metabolism in the resting state. In addition, we summarize some future challenges and interesting research directions for ASL, including slice-accelerated (multiband) imaging as well as the effects of motion and other physiological confounds on perfusion-based FC measurement. In summary, this work reviews the state-of-the-art of ASL and establishes it as an increasingly viable MRI technique with high translational value in studying resting-state brain function.

  11. Assessment of vascular autonomic function using peripheral arterial tonometry.

    PubMed

    Hamada, Satomi; Oono, Ai; Ishihara, Yuri; Hasegawa, Yuki; Akaza, Miho; Sumi, Yuki; Inoue, Yoshinori; Izumiyama, Hajime; Hirao, Kenzo; Isobe, Mitsuaki; Sasano, Tetsuo

    2017-03-01

    Peripheral autonomic function is impaired in diabetic polyneuropathy. However, it is difficult to evaluate it due to the lack of non-invasive quantitative assessment. We aimed to establish a novel index to evaluate vascular autonomic function using reactive hyperemia peripheral arterial tonometry (RH-PAT), a widely performed endothelial function test. Sixty-five subjects were enrolled, including healthy subjects, cases with sympathetic nerve blockers, and diabetic patients. RH-PAT was performed with 5-min blood flow occlusion in unilateral arm. We calculated the reduction ratio of the post-occlusion pulse amplitude to the baseline in the non-occluded arm (RPN), with 1-min sliding window. In healthy subjects, RPN gradually increased with time-dependent manner. However, this phenomenon was eliminated in cases with sympathetic nerve blockers. Plasma concentration of norepinephrine was measured before and after the blood flow occlusion, which showed a significant increase. We then compared RPNs with the change in heart rate variability (HRV) parameters. RPN calculated at 5 min after the reperfusion had the highest correlation with the change in sympathetic HRV parameter, and thus, we named sympathetic hypoemia index (SHI). Finally, we studied the relationship between SHI and diabetes. SHI was significantly lower in diabetic patients than matched controls. SHI, a novel index derived from RH-PAT, represented the peripheral sympathetic activity. SHI may be useful for assessing the vascular autonomic activity in diabetic patients.

  12. High sugar intake via the renin-angiotensin system blunts the baroreceptor reflex in adult rats that were perinatally depleted of taurine.

    PubMed

    Thaeomor, Atcharaporn; Wyss, J Michael; Jirakulsomchok, Dusit; Roysommuti, Sanya

    2010-08-24

    Perinatal taurine depletion leads to several physiological impairments in adult life, in part, due to taurine's effects on the renin-angiotensin system, a crucial regulator of growth and differentiation during early life. The present study tests the hypothesis that perinatal taurine depletion predisposes adult female rats to impaired baroreceptor control of arterial pressure by altering the renin-angiotensin system. Female Sprague Dawley (SD) rats were fed normal rat chow and from conception to weaning drank 3% beta-alanine in water (taurine depletion, TD) or water alone (Control, C). Female offspring ate a normal rat chow and drank water with (G) or without (W) 5% glucose throughout the experiment. To test the possible role of the renin-angiotensin system, 50% of the rats received captopril (an angiotensin converting enzyme inhibitor, 400 mg/L) from 7 days before parameter measurements until the end of experiment. At 7-8 weeks of age, arterial pressure, heart rate, baroreflex control of heart rate and renal nerve activity were studied in either conscious, freely moving or anesthetized rats. Perinatal taurine depletion did not alter resting mean arterial pressure or heart rate in the adult female offspring that received either high or normal sugar intake. Captopril treatment slightly decreased mean arterial pressure but not heart rate in all groups. Compared to controls, only the TDG rats displayed blunted baroreflex responses. Captopril treatment normalized baroreflex sensitivity in TDG. The present data indicate that in perinatal taurine depleted female rats, the renin-angiotensin system underlines the ability of high sugar intake to blunt baroreceptor responses.

  13. Control of the Myocardial Contractile State by Carotid Chemo- and Baroreceptor and Pulmonary Inflation Reflexes in Conscious Dogs

    PubMed Central

    Vatner, Stephen F.; Rutherford, John D.

    1978-01-01

    The effects of carotid chemoreceptor stimulation with intracarotid injections of either nicotine, 0.2 μg/kg, or cyanide, 2 μg/kg, were compared with the effects of bilateral carotid occlusion on left ventricular (LV) pressure, dP/dt, and diameter in conscious dogs instrumented with ultrasonic diameter gauges and miniature pressure gauges. With heart rate maintained constant, carotid chemoreceptor stimulation increased mean arterial pressure by 27±3%, LV and diastolic diameter by 4±0.9% and LV dP/dt by 21±2%. With ventilation controlled during succinylcholine infusion, carotid chemoreceptor stimulation increased mean arterial pressure by 43±2% and dP/dt by 37±5%, values significantly greater, P < 0.01, than were observed in dogs with spontaneous ventilation. Similarly, in dogs with spontaneous ventilation after vagotomy, carotid chemoreceptor stimulation also increased dP/dt by a greater amount, i.e., by 48±9%. The increases in LV end diastolic diameter were not affected significantly by either cholinergic blockade with atropine or beta adrenergic blockade with propranolol. Although cholinergic blockade did not affect the inotropic or pressor responses significantly, beta adrenergic blockade attenuated the pressor response and essentially abolished the inotropic response. Bilateral carotid occlusion increased mean arterial pressure and LV end diastolic diameter by similar amounts to those observed with chemoreceptor stimulation, but increased dP/dt significantly less, P < 0.02, i.e., by 13±2%. As was observed with chemoreceptor stimulation, inotropic responses were not affected significantly by cholinergic blockade, but were essentially abolished by beta adrenergic blockade. Thus, in the conscious dog with heart rate constant, carotid chemoreceptor stimulation induces a clear positive inotropic effect, which is greater in the absence of the attenuating influences of pulmonary inflation reflexes, and for an equal elevation in arterial pressure appears to

  14. Alterations in arterial function after high-voltage electrical injury

    PubMed Central

    2012-01-01

    Introduction The aim of this study was to evaluate the functional changes of the arterial endothelium and smooth muscle after a high-voltage electrical injury (HVEI), using flow-mediated dilation (FMD) and nitrate-mediated dilation (NMD). Methods Twenty-five male patients injured in the upper extremities by current due to contact with more than 20,000 volts were enrolled in the study. FMD and NMD were measured on the brachial artery within 48 hours after HVEI, and follow-up FMD and NMD were evaluated six weeks later. In addition, we enrolled an age, sex and body mass index matched healthy control group consisting of 25 individuals. Including FMD and NMD, all the variables of the control group were investigated one time and compared with the initial and six week follow-up data of the HVEI group. Results A significantly lower initial FMD was seen in the HVEI group compared with the control group (2.1 ± 1.2% versus 13.6 ± 3.4%, P < 0.01). At the six week follow-up, the FMD of the HVEI group had significantly improved compared to the initial FMD (2.1 ± 1.2% versus 5.1 ± 2.1%, P < 0.01), but it was still lower than the FMD of the control group (5.1 ± 2.1% versus 13.6 ± 3.4%, P < 0.01). A significantly lower NMD was seen both initially and at the six week follow-up compared with the NMD of the control group (7.3 ± 4.7% versus 20.4 ± 4.1%, P < 0.01 and 11.4 ± 6.7% versus 20.4 ± 4.1%, P < 0.01, respectively). The FMD study of the contralateral arm which was uninjured by HVEI was available in six patients. In those patients, the six week follow-up FMD was significantly improved in the HVEI arm compared with the initial FMD (1.8 ± 0.6% versus 4.4 ± 1.6%, P < 0.01). However, in the contralateral uninjured arm, there was no difference between the initial and the six week follow-up FMDs (5.5 ± 1.4% versus 6.9 ± 2.2%, P = 0.26). Conclusions After HVEI, the endothelial and smooth muscle functions of the brachial artery were significantly decreased for at least six

  15. Outcomes of anatomical versus functional testing for coronary artery disease.

    PubMed

    Douglas, Pamela S; Hoffmann, Udo; Patel, Manesh R; Mark, Daniel B; Al-Khalidi, Hussein R; Cavanaugh, Brendan; Cole, Jason; Dolor, Rowena J; Fordyce, Christopher B; Huang, Megan; Khan, Muhammad Akram; Kosinski, Andrzej S; Krucoff, Mitchell W; Malhotra, Vinay; Picard, Michael H; Udelson, James E; Velazquez, Eric J; Yow, Eric; Cooper, Lawton S; Lee, Kerry L

    2015-04-02

    Many patients have symptoms suggestive of coronary artery disease (CAD) and are often evaluated with the use of diagnostic testing, although there are limited data from randomized trials to guide care. We randomly assigned 10,003 symptomatic patients to a strategy of initial anatomical testing with the use of coronary computed tomographic angiography (CTA) or to functional testing (exercise electrocardiography, nuclear stress testing, or stress echocardiography). The composite primary end point was death, myocardial infarction, hospitalization for unstable angina, or major procedural complication. Secondary end points included invasive cardiac catheterization that did not show obstructive CAD and radiation exposure. The mean age of the patients was 60.8±8.3 years, 52.7% were women, and 87.7% had chest pain or dyspnea on exertion. The mean pretest likelihood of obstructive CAD was 53.3±21.4%. Over a median follow-up period of 25 months, a primary end-point event occurred in 164 of 4996 patients in the CTA group (3.3%) and in 151 of 5007 (3.0%) in the functional-testing group (adjusted hazard ratio, 1.04; 95% confidence interval, 0.83 to 1.29; P=0.75). CTA was associated with fewer catheterizations showing no obstructive CAD than was functional testing (3.4% vs. 4.3%, P=0.02), although more patients in the CTA group underwent catheterization within 90 days after randomization (12.2% vs. 8.1%). The median cumulative radiation exposure per patient was lower in the CTA group than in the functional-testing group (10.0 mSv vs. 11.3 mSv), but 32.6% of the patients in the functional-testing group had no exposure, so the overall exposure was higher in the CTA group (mean, 12.0 mSv vs. 10.1 mSv; P<0.001). In symptomatic patients with suspected CAD who required noninvasive testing, a strategy of initial CTA, as compared with functional testing, did not improve clinical outcomes over a median follow-up of 2 years. (Funded by the National Heart, Lung, and Blood Institute

  16. Outcomes of Anatomical versus Functional Testing for Coronary Artery Disease

    PubMed Central

    Douglas, Pamela S.; Hoffmann, Udo; Patel, Manesh R.; Mark, Daniel B.; Al-Khalidi, Hussein R.; Cavanaugh, Brendan; Cole, Jason; Dolor, Rowena J.; Fordyce, Christopher B.; Huang, Megan; Khan, Muhammad Akram; Kosinski, Andrzej S.; Krucoff, Mitchell W.; Malhotra, Vinay; Picard, Michael H.; Udelson, James E.; Velazquez, Eric J.; Yow, Eric; Cooper, Lawton S.; Lee, Kerry L.

    2015-01-01

    BACKGROUND Many patients have symptoms suggestive of coronary artery disease (CAD) and are often evaluated with the use of diagnostic testing, although there are limited data from randomized trials to guide care. METHODS We randomly assigned 10,003 symptomatic patients to a strategy of initial anatomical testing with the use of coronary computed tomographic angiography (CTA) or to functional testing (exercise electrocardiography, nuclear stress testing, or stress echocardiography). The composite primary end point was death, myocardial infarction, hospitalization for unstable angina, or major procedural complication. Secondary end points included invasive cardiac catheterization that did not show obstructive CAD and radiation exposure. RESULTS The mean age of the patients was 60.8±8.3 years, 52.7% were women, and 87.7% had chest pain or dyspnea on exertion. The mean pretest likelihood of obstructive CAD was 53.3±21.4%. Over a median follow-up period of 25 months, a primary end-point event occurred in 164 of 4996 patients in the CTA group (3.3%) and in 151 of 5007 (3.0%) in the functional-testing group (adjusted hazard ratio, 1.04; 95% confidence interval, 0.83 to 1.29; P = 0.75). CTA was associated with fewer catheterizations showing no obstructive CAD than was functional testing (3.4% vs. 4.3%, P = 0.02), although more patients in the CTA group underwent catheterization within 90 days after randomization (12.2% vs. 8.1%). The median cumulative radiation exposure per patient was lower in the CTA group than in the functional-testing group (10.0 mSv vs. 11.3 mSv), but 32.6% of the patients in the functional-testing group had no exposure, so the overall exposure was higher in the CTA group (mean, 12.0 mSv vs. 10.1 mSv; P<0.001). CONCLUSIONS In symptomatic patients with suspected CAD who required noninvasive testing, a strategy of initial CTA, as compared with functional testing, did not improve clinical outcomes over a median follow-up of 2 years. (Funded by the

  17. Superficial femoral artery plaque and functional performance in peripheral arterial disease: walking and leg circulation study (WALCS III).

    PubMed

    McDermott, Mary M; Liu, Kiang; Carroll, Timothy J; Tian, Lu; Ferrucci, Luigi; Li, Debiao; Carr, James; Guralnik, Jack M; Kibbe, Melina; Pearce, William H; Yuan, Chun; McCarthy, Walter; Kramer, Christopher M; Tao, Huimin; Liao, Yihua; Clark, Elizabeth Talley; Xu, Dongxiang; Berry, Jarett; Orozco, Jennifer; Sharma, Leena; Criqui, Michael H

    2011-07-01

    We studied associations of magnetic resonance imaging measurements of plaque area and relative percent lumen reduction in the proximal superficial femoral artery with functional performance among participants with peripheral arterial disease. The clinical significance of directly imaged plaque characteristics in lower extremity arteries is not well established. A total of 454 participants with an ankle brachial index <1.00 underwent magnetic resonance cross-sectional imaging of the proximal superficial femoral artery and completed a 6-min walk test, measurement of 4-m walking velocity at usual and fastest pace, and measurement of physical activity with a vertical accelerometer. Adjusting for age, sex, race, body mass index, smoking, statin use, comorbidities, and other covariates, higher mean plaque area (1st quintile [least plaque]: 394 m, 2nd quintile: 360 m, 3rd quintile: 359 m, 4th quintile: 329 m, 5th quintile [greatest plaque]: 311 m; p trend <0.001) and smaller mean percent lumen area (1st quintile [greatest plaque]: 319 m, 2nd quintile: 330 m, 3rd quintile: 364 m, 4th quintile: 350 m, 5th quintile: 390 m; p trend <0.001) were associated with shorter distance achieved in the 6-min walk test. Greater mean plaque area was also associated with slower usual-paced walking velocity (p trend = 0.006) and slower fastest-paced 4-m walking velocity (p trend = 0.003). Associations of mean plaque area and mean lumen area with 6-min walk distance remained statistically significant even after additional adjustment for the ankle brachial index and leg symptoms. Among participants with peripheral arterial disease, greater plaque burden and smaller lumen area in the proximal superficial femoral artery are associated independently with poorer functional performance, even after adjusting for the ankle brachial index and leg symptoms. Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  18. Surgical neuroangiography. Vol. 1: Functional anatomy of craniofacial arteries

    SciTech Connect

    Lasjaunias, P.; Berenstein, A.

    1987-01-01

    The contents of this book are: Arterial Anatomy: Introduction. - The Internal Maxillary System. - The Pharyngo-occipital System. - The Upper Cervical Vertebral Column: The Cervical Arteries. - The Musculocutaneous Elements of the Head and Mouth. - Thyrolaryngeal Arteries. - The Transosseous Peripheral Nervous System Arterial Supply. - Dangerous Vessels. - Collateral Circulation. - The Pharyngoocipital Collateral Pattern. - The Internal Maxillary Collateral Pattern. - The Linguofacial Collateral Pattern. - Multiple Constraints and Chronology of the Collateral Response. - Angiographic Protocols. - Angiographic Protocol of the Parasellar Region. - Angiographic Protocol of the Posterior Base of the Skull. - Angiographic Protocol of the Carotid Region. - Angiographic Protocol of the Nasomaxillaary Region. - Angiographic Protocol of the Maxillomandibular Region. - Angiographic Protocol of the Temporofacial and Scalp Region. - Angiographic Protocol of the Thyrolaryngeal Region. - References. - Subject Index.

  19. Influence of central venous pressure upon sinus node responses to arterial baroreflex stimulation in man

    NASA Technical Reports Server (NTRS)

    Mark, A. L.; Takeshita, A.; Eckberg, D. L.; Abboud, F. M.

    1978-01-01

    Measurements were made of sinus node responses to arterial baroreceptor stimulation with phenylephrine injection or neck suction, before and during changes of central venous pressure provoked by lower body negative pressure or leg and lower truck elevation. Variations of central venous pressure between 1.1 and 9.0 mm Hg did not influence arterial baroreflex mediated bradycardia. Baroreflex sinus node responses were augmented by intravenous propranolol, but the level of responses after propranolol was comparable during the control state, lower body negative pressure, and leg and trunk elevation. Sinus node responses to very brief baroreceptor stimuli applied during the transitions of central venous pressure also were comparable in the three states. The authors conclude that physiological variations of central venous pressure do not influence sinus node responses to arterial baroreceptor stimulation in man.

  20. Prognostic Value of Gai's Plaque Score and Agatston Coronary Artery Calcium Score for Functionally Significant Coronary Artery Stenosis

    PubMed Central

    Zhang, Chuang; Yang, Shuang; Gai, Lu-Yue; Han, Zhi-Qi; Xin, Qian; Yang, Xiao-Bo; Yang, Jun-Jie; Jin, Qin-Hua

    2016-01-01

    Background: The prognostic values of the coronary computed tomography angiography (CCTA) score for predicting future cardiovascular events have been previously demonstrated in numerous studies. However, few studies have used the rich information available from CCTA to detect functionally significant coronary lesions. We sought to compare the prognostic values of Gai's plaque score and the coronary artery calcium score (CACS) of CCTA for predicting functionally significant coronary lesions, using fractional flow reserve (FFR) as the gold standard. Methods: We retrospectively analyzed 107 visually assessed significant coronary lesions in 88 patients (mean age, 59.6 ± 10.2 years; 76.14% of males) who underwent CCTA, invasive coronary angiography, and invasive FFR measurement. An FFR <0.80 indicated hemodynamically significant coronary stenosis. Lesions were divided into two groups using an FFR cutoff value of 0.80. We compared Gai's plaque scores and CACS between the two groups and evaluated the correlations of these scores with FFR. The statistical methods included unpaired t-test, Mann-Whitney U-test, and Spearman's correlation coefficients. Results: Coronary lesions with FFR <0.80 had higher Gai's scores than those with FFR ≥0.80. Gai's score had the strongest correlation with FFR (r = −0.48, P < 0.01) and had a greater area under the curve = 0.72 (95% confidence interval: 0.61–0.82; P < 0.01) than the CACS of whole arteries and a single artery. Conclusions: Both CACS in a single artery and Gai's plaque score demonstrated a good capacity to assess functionally significant coronary artery stenosis when compared to the gold standard FFR. However, Gai's plaque score was more predictive of FFR <0.80. Gai's score can be easily calculated in daily clinical practice and could be used when considering revascularization. PMID:27900990

  1. Assessments of arterial stiffness and endothelial function using pulse wave analysis.

    PubMed

    Stoner, Lee; Young, Joanna M; Fryer, Simon

    2012-01-01

    Conventionally, the assessments of endothelial function and arterial stiffness require different sets of equipment, making the inclusion of both tests impractical for clinical and epidemiological studies. Pulse wave analysis (PWA) provides useful information regarding the mechanical properties of the arterial tree and can also be used to assess endothelial function. PWA is a simple, valid, reliable, and inexpensive technique, offering great clinical and epidemiological potential. The current paper will outline how to measure arterial stiffness and endothelial function using this technique and include discussion of validity and reliability.

  2. Interaction of semicircular canal stimulation with carotid baroreceptor reflex control of heart rate

    NASA Technical Reports Server (NTRS)

    Convertino, V. A.

    1998-01-01

    The carotid-cardiac baroreflex contributes to the prediction of orthostatic tolerance; experimental attenuation of the reflex response leads to orthostatic hypotension in humans and animals. Anecdotal observations indicate that rotational head movements about the vertical axis of the body can also induce orthostatic bradycardia and hypotension through increased parasympathetic activity. We therefore measured the chronotropic response to carotid baroreceptor stimulation in 12 men during varying conditions of vestibulo-oculomotor stimulation to test the hypothesis that stimulation of the semicircular canals associated with head movements in the yaw plane inhibits cardioacceleration through a vagally mediated baroreflex. Carotid-cardiac baroreflex response was assessed by plotting R-R intervals (ms) at each of 8 neck pressure steps with their respective carotid distending pressures (mmHg). Calculated baroreflex gain (maximal slope of the stimulus-response relationship) was measured under 4 experimental conditions: 1) sinusoidal whole-body yaw rotation of the subject in the dark without visual fixation (combined vestibular-oculomotor stimulation); 2) yaw oscillation of the subject while tracking a small head-fixed light moving with the subject (vestibular stimulation without eye movements); 3) subject stationary while fixating on a small light oscillating in yaw at the same frequency, peak acceleration, and velocity as the chair (eye movements without vestibular stimulation); and 4) subject stationary in the dark (no eye or head motion). Head motion alone and with eye movement reduced baseline baroreflex responsiveness to the same stimulus by 30%. Inhibition of cardioacceleration during rotational head movements may have significant impact on functional performance in aerospace environments, particularly in high-performance aircraft pilots during high angular acceleration in aerial combat maneuvers or in astronauts upon return from spaceflight who already have

  3. Interaction of semicircular canal stimulation with carotid baroreceptor reflex control of heart rate

    NASA Technical Reports Server (NTRS)

    Convertino, V. A.

    1998-01-01

    The carotid-cardiac baroreflex contributes to the prediction of orthostatic tolerance; experimental attenuation of the reflex response leads to orthostatic hypotension in humans and animals. Anecdotal observations indicate that rotational head movements about the vertical axis of the body can also induce orthostatic bradycardia and hypotension through increased parasympathetic activity. We therefore measured the chronotropic response to carotid baroreceptor stimulation in 12 men during varying conditions of vestibulo-oculomotor stimulation to test the hypothesis that stimulation of the semicircular canals associated with head movements in the yaw plane inhibits cardioacceleration through a vagally mediated baroreflex. Carotid-cardiac baroreflex response was assessed by plotting R-R intervals (ms) at each of 8 neck pressure steps with their respective carotid distending pressures (mmHg). Calculated baroreflex gain (maximal slope of the stimulus-response relationship) was measured under 4 experimental conditions: 1) sinusoidal whole-body yaw rotation of the subject in the dark without visual fixation (combined vestibular-oculomotor stimulation); 2) yaw oscillation of the subject while tracking a small head-fixed light moving with the subject (vestibular stimulation without eye movements); 3) subject stationary while fixating on a small light oscillating in yaw at the same frequency, peak acceleration, and velocity as the chair (eye movements without vestibular stimulation); and 4) subject stationary in the dark (no eye or head motion). Head motion alone and with eye movement reduced baseline baroreflex responsiveness to the same stimulus by 30%. Inhibition of cardioacceleration during rotational head movements may have significant impact on functional performance in aerospace environments, particularly in high-performance aircraft pilots during high angular acceleration in aerial combat maneuvers or in astronauts upon return from spaceflight who already have

  4. From Newborn to Senescence Morphological and Functional Remodeling Leads to Increased Contractile Capacity of Arteries.

    PubMed

    Ivic, Ivan; Vamos, Zoltan; Cseplo, Peter; Koller, Akos

    2017-04-01

    Aging induces substantial morphological and functional changes in vessels. We hypothesized that due to morphological remodeling the total contractile forces of arteries increase, especially in older age as a function of age. Mean arterial blood pressure of rats and morphological and functional characteristics of isolated carotid arteries rats, from newborn to senescent, were assessed. The arterial blood pressure of rats increased significantly from 0.25 to the age of 6 months, and then it reached a level, which was maintained until age of 30 months. Wall lumen and wall thickness increased with age, mostly due to media (smooth muscle) thickening, whereas wall tension gradually reduced with age. Contractions of arteries to nonreceptor-mediated vasomotor agent (KCl, 60mM) increased in three consecutive age groups, whereas contractility first increased (until 2 months), then it did not change further with aging. Norepinephrine-induced contractions initially increased in young age and then did not change further in older age. These findings suggest that during normal aging due to remodeling of arterial wall (smooth muscle) the contractile capacity of arteries increases, which seems to be independent from systemic blood pressure. Thus, arterial remodeling can favor the development of increased circulatory resistance in older age.

  5. Posterior cerebral artery laterality on magnetic resonance angiography predicts long-term functional outcome in middle cerebral artery occlusion.

    PubMed

    Ichijo, Masahiko; Miki, Kazunori; Ishibashi, Satoru; Tomita, Makoto; Kamata, Tomoyuki; Fujigasaki, Hiroto; Mizusawa, Hidehiro

    2013-02-01

    Prominent posterior cerebral artery (PCA) laterality upon 3-dimensional time-of-flight magnetic resonance angiography is often encountered in patients with middle cerebral artery occlusion. We hypothesized that this sign is correlated with improved functional outcome in patients with middle cerebral artery occlusion treated with intravenous recombinant tissue plasminogen activator. Fifty acute ischemic stroke patients with middle cerebral artery occlusion were treated with intravenous recombinant tissue plasminogen activator from April 2007 to October 2009. All patients routinely underwent initial (first 3 hours) magnetic resonance scans on admission, and additional follow-up (14-21 days after stroke onset) computed tomography scans. Two film readers blinded to all clinical information assessed the presence or absence of PCA laterality on magnetic resonance angiography. We retrospectively analyzed the clinical and radiologic data on all patients. Out of 50 patients, 20 showed PCA laterality on magnetic resonance angiography. National Institute of Health Stroke Scale score 7 days after stroke onset was significantly lower (P=0.007), and infarct volume on follow-up computed tomography was significantly smaller (P=0.009) in patients with PCA laterality than in patients without this sign. Multivariate logistic regression analyses showed an adjusted odds ratio of 8.49 for a favorable outcome (modified Rankin Scale score 0-1 at 6 months) in patients with PCA laterality (95% CI: 1.82 to 55.8, P=0.005). The presence of PCA laterality on magnetic resonance angiography before intravenous recombinant tissue plasminogen activator can be used as a predictor of favorable functional outcome in patients with middle cerebral artery occlusion, probably due to improvement of recanalization rate.

  6. Arterial endothelial function in a porcine model of early stage atherosclerotic vascular disease

    PubMed Central

    Turk, James R; Henderson, Kyle K; Vanvickle, Gregory D; Watkins, Justin; Laughlin, M Harold

    2005-01-01

    Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the United States and is projected to become the leading cause of mortality in the world. Atherosclerosis is the most important single factor contributing to this disease burden. In this study, we characterize relationships between endothelial dysfunction and vascular disease in an animal model of diet-induced, early-stage atherosclerotic vascular disease. We tested the hypothesis that hypercholesterolaemia induces vascular disease and impairs endothelium-dependent relaxation (EDR) in conduit arteries of adult male Yucatan pigs. Pigs were fed a normal fat (NF) or high fat cholesterol (HFC) diet for 20–24 weeks. Results indicate that, while the HFC diet did not alter EDR in femoral or brachial arteries, EDR was significantly decreased in both carotid and coronary arteries. Sudanophilic fatty streaks were significantly present in the abdominal aorta and common carotid artery. Histopathology revealed increased intima-media thickness (IMT) and foam cell accumulation in Stary Stage I–III lesions in the abdominal aorta, common carotid artery and femoral arteries. In the coronary arteries, the accumulation of foam cells in Stary Stage I and II lesions resulted in a trend for increased IMT. There was no evidence of vascular disease in the brachial arteries. These results indicate that early stages of CVD (Stary Stage I–III) precede decreases in EDR induced by HFC diet, because femoral arteries exhibited foam cell accumulation and an increased IMT but no change in endothelial function. PMID:16191105

  7. Effect of habitual aerobic exercise on body weight and arterial function in overweight and obese men.

    PubMed

    Miyaki, Asako; Maeda, Seiji; Yoshizawa, Mutsuko; Misono, Maiko; Saito, Yoko; Sasai, Hiroyuki; Kim, Maeng-Kyu; Nakata, Yoshio; Tanaka, Kiyoji; Ajisaka, Ryuichi

    2009-09-15

    The effect of habitual exercise on vascular function, including central arterial distensibility and endothelial function, in obese subjects has not yet been clarified. We investigated whether aerobic exercise training affects central arterial distensibility and endothelial function in middle-age overweight and obese men. A total of 21 overweight and obese men (age 50 +/- 2 years, body mass index 30 +/- 1 kg/m(2)) completed a 12-week aerobic exercise intervention. Aerobic exercise training significantly reduced their body weight and resulted in a significant decrease in body mass index. After the weight-reduction exercise program, carotid arterial compliance (determined by simultaneous B-mode ultrasonography and arterial applanation tonometry on the common carotid artery) significantly increased; and the beta-stiffness index, an index of arterial compliance adjusted for distending pressure, significantly decreased. The concentrations of plasma endothelin-1, a potent vasoconstrictor peptide produced by vascular endothelial cells, significantly decreased and plasma nitric oxide (measured as the stable end product [nitrite/nitrate]), a potent vasodilator produced by vascular endothelial cells, significantly increased after the weight-reduction exercise program. In conclusion, weight reduction by aerobic exercise training in overweight and obese men increased the central arterial distensibility. This increase might contribute to the improvement in endothelial function, as assessed by a decrease in endothelin-1 and an increase in nitric oxide, after exercise training-induced weight loss.

  8. Evidence for local relaxin ligand-receptor expression and function in arteries.

    PubMed

    Novak, Jacqueline; Parry, Laura J; Matthews, Julianna E; Kerchner, Laurie J; Indovina, Kimberly; Hanley-Yanez, Karen; Doty, Ketah D; Debrah, Dan O; Shroff, Sanjeev G; Conrad, Kirk P

    2006-11-01

    Relaxin is a 6 kDa protein hormone produced by the corpus luteum and secreted into the blood during pregnancy in rodents and humans. Growing evidence indicates that circulating relaxin causes vasodilatation and increases in arterial compliance, which may be among its most important actions during pregnancy. Here we investigated whether there is local expression and function of relaxin and relaxin receptor in arteries of nonpregnant females and males. Relaxin-1 and its major receptor, Lgr7, mRNA are expressed in thoracic aortas, small renal and mesenteric arteries from mice and rats of both sexes, as well as in small renal arteries from female tammar wallabies (an Australian marsupial). Using available antibodies for rat and mouse Lgr7 receptor and rat relaxin, we also identified protein expression in arteries. Small renal arteries isolated from relaxin-1 gene-deficient mice demonstrate enhanced myogenic reactivity and decreased passive compliance relative to wild-type (WT) and heterozygous mice. Taken together, these findings reveal an arterial-derived, relaxin ligand-receptor system that acts locally to regulate arterial function.

  9. Functional assessment of a left coronary-pulmonary artery fistula by coronary flow reserve

    PubMed Central

    Sasi, Viktor; Forster, Tamás; Ungi, Imre

    2014-01-01

    We report a 71-year-old man who presented with atypical chest pain. Coronary angiography did not reveal left main or proximal left anterior descending coronary artery stenosis, but a fistulous communication with a stronger tube-like fistula was present originating from the proximal left anterior descending coronary artery and emptying into the main pulmonary artery. Fractional flow reserve and coronary flow reserve measurements were performed to gain more data on the potential functional aspects of this fistula. With the present case, the importance of functional evaluation of these fistulas is demonstrated. PMID:25061466

  10. Arterial Stiffness and Wave Reflection: Sex Differences and Relationship with Left Ventricular Diastolic Function

    PubMed Central

    Russo, Cesare; Jin, Zhezhen; Palmieri, Vittorio; Homma, Shunichi; Rundek, Tatjana; Elkind, Mitchell S.V.; Sacco, Ralph L.; Di Tullio, Marco R.

    2012-01-01

    Increased arterial stiffness and wave reflection have been reported in heart failure with normal ejection fraction (HFNEF) and in asymptomatic left ventricular (LV) diastolic dysfunction, a precursor of HFNEF. It is unclear whether women, who have higher frequency of HFNEF, are more vulnerable than men to the deleterious effects of arterial stiffness on LV diastolic function. We investigated in a large community-based cohort, whether sex differences exist in the relationship between arterial stiffness, wave reflection and LV diastolic function. Arterial stiffness and wave reflection were assessed in 983 participants from the Cardiovascular Abnormalities and Brain Lesions (CABL) study using applanation tonometry. Central pulse pressure/stroke volume index (cPP/SVi), total arterial compliance, pulse pressure amplification and augmentation index were used as parameters of arterial stiffness and wave reflection. LV diastolic function was evaluated by two-dimensional echocardiography and tissue-Doppler imaging. Arterial stiffness and wave reflection were greater in women compared to men, independent of body size and heart rate (all p<0.01), and showed inverse relationships with parameters of diastolic function in both sexes. Further adjustment for cardiovascular risk factors attenuated these relationships; however, higher cPP/SVi predicted LV diastolic dysfunction in women [odds ratio (OR) 1.54, 95% confidence intervals (CI) 1.03–2.30] and men (OR: 2.09, 95% CI 1.30–3.39) independent of other risk factors. In conclusion, in our community-based cohort study, higher arterial stiffness was associated with worse LV diastolic function in men and women. Women’s higher arterial stiffness, independent of body size, may contribute to their greater susceptibility to develop HFNEF. PMID:22753223

  11. Differential effect of central command on aortic and carotid sinus baroreceptor-heart rate reflexes at the onset of spontaneous, fictive motor activity.

    PubMed

    Matsukawa, Kanji; Ishii, Kei; Kadowaki, Akito; Liang, Nan; Ishida, Tomoko

    2012-08-15

    Our laboratory has reported that central command blunts the sensitivity of the aortic baroreceptor-heart rate (HR) reflex at the onset of voluntary static exercise in conscious cats and spontaneous contraction in decerebrate cats. The purpose of this study was to examine whether central command attenuates the sensitivity of the carotid sinus baroreceptor-HR reflex at the onset of spontaneous, fictive motor activity in paralyzed, decerebrate cats. We confirmed that aortic nerve (AN)-stimulation-induced bradycardia was markedly blunted to 26 ± 4.4% of the control (21 ± 1.3 beats/min) at the onset of spontaneous motor activity. Although the baroreflex bradycardia by electrical stimulation of the carotid sinus nerve (CSN) was suppressed (P < 0.05) to 86 ± 5.6% of the control (38 ± 1.2 beats/min), the inhibitory effect of spontaneous motor activity was much weaker (P < 0.05) with CSN stimulation than with AN stimulation. The baroreflex bradycardia elicited by brief occlusion of the abdominal aorta was blunted to 36% of the control (36 ± 1.6 beats/min) during spontaneous motor activity, suggesting that central command is able to inhibit the cardiomotor sensitivity of arterial baroreflexes as the net effect. Mechanical stretch of the triceps surae muscle never affected the baroreflex bradycardia elicited by AN or CSN stimulation and by aortic occlusion, suggesting that muscle mechanoreflex did not modify the cardiomotor sensitivity of aortic and carotid sinus baroreflex. Since the inhibitory effect of central command on the carotid baroreflex pathway, associated with spontaneous motor activity, was much weaker compared with the aortic baroreflex pathway, it is concluded that central command does not force a generalized modulation on the whole pathways of arterial baroreflexes but provides selective inhibition for the cardiomotor component of the aortic baroreflex.

  12. Insulin Enhances Endothelial Function Throughout the Arterial Tree in Healthy But Not Metabolic Syndrome Subjects

    PubMed Central

    Jahn, Linda A.; Hartline, Lee; Rao, Nagashree; Logan, Brent; Kim, Justin J.; Aylor, Kevin; Gan, Li-Ming; Westergren, Helena U.

    2016-01-01

    Context: Insulin reportedly impairs endothelial function in conduit arteries but improves it in resistance and microvascular arterioles in healthy humans. No studies have assessed endothelial function at three arterial levels in healthy or metabolic syndrome (METSYN) subjects. Objective: The objective of the study was to compare endothelial responsiveness of conduit arteries, resistance, and microvascular arterioles to insulin in healthy and METSYN subjects. Design: We assessed conduit, resistance, and microvascular arterial function in the postabsorptive and postprandial states and during euglycemic hyperinsulinemia (insulin clamp). Setting: The study was conducted at a clinical research unit. Participants: Age-matched healthy and METSYN subjects participated in the study. Interventions: We used brachial flow-mediated dilation, forearm postischemic flow velocity, and contrast-enhanced ultrasound to assess the conduit artery, resistance arteriole, and microvascular arteriolar endothelial function, respectively. We also assessed the conduit artery stiffness (pulse wave velocity and augmentation index) and measured the plasma concentrations of 92 cardiovascular disease biomarkers at baseline and after the clamp. Results: Postabsorptive and postprandial endothelial function was similar in controls and METSYN in all tested vessels. METSYN subjects were metabolically insulin resistant (P < .005). In controls, but not METSYN subjects, during euglycemic hyperinsulinemia, endothelial function improved at each level of arterial vasculature (P < .05 or less for each). Conduit vessel stiffness (pulse wave velocity) was increased in the METSYN group. Twelve of 92 biomarkers differed at baseline (P < .001) and remained different at the end of the insulin clamp. Conclusions: We conclude that insulin enhances arterial endothelial function in health but not in METSYN, and this vascular insulin resistance may underlie its increased cardiovascular disease risk. PMID:26756115

  13. Development of functional in vivo imaging of cerebral lenticulostriate artery using novel synchrotron radiation angiography

    NASA Astrophysics Data System (ADS)

    Lin, Xiaojie; Miao, Peng; Mu, Zhihao; Jiang, Zhen; Lu, Yifan; Guan, Yongjing; Chen, Xiaoyan; Xiao, Tiqiao; Wang, Yongting; Yang, Guo-Yuan

    2015-02-01

    The lenticulostriate artery plays a vital role in the onset and development of cerebral ischemia. However, current imaging techniques cannot assess the in vivo functioning of small arteries such as the lenticulostriate artery in the brain of rats. Here, we report a novel method to achieve a high resolution multi-functional imaging of the cerebrovascular system using synchrotron radiation angiography, which is based on spatio-temporal analysis of contrast density in the arterial cross section. This method provides a unique tool for studying the sub-cortical vascular elasticity after cerebral ischemia in rats. Using this technique, we demonstrated that the vascular elasticity of the lenticulostriate artery decreased from day 1 to day 7 after transient middle cerebral artery occlusion in rats and recovered from day 7 to day 28 compared to the controls (p < 0.001), which paralleled with brain edema formation and inversely correlated with blood flow velocity (p < 0.05). Our results demonstrated that the change of vascular elasticity was related to the levels of brain edema and the velocity of focal blood flow, suggesting that reducing brain edema is important for the improvement of the function of the lenticulostriate artery in the ischemic brain.

  14. Improvement of left ventricular exercise hemodynamic function after aorta-coronary artery bypass grafting.

    PubMed

    Vlietstra, R E; Chesebro, J H; Frye, R L; Wallace, R B

    1981-01-01

    In 39 patients with coronary artery disease and angina pectoris, exercise hemodynamic evaluation, left ventriculography, and coronary arteriography were performed both before and 3 to 36 months (mean 17 months) after aorta-coronary artery bypass grafting. Of the 32 patients with abnormal exercise hemodynamic responses before operation, 11 returned to normal at the postoperative study (Group N) and 21 remained abnormal (Group A). Preoperative characteristics (mean age, functional class, prior myocardial infarction, left ventriculographic appearance, mean ejection fraction, and mean number of vessels diseased) were similar in the two groups. Of the perioperative and postoperative characteristics examined (mean number of grafts, operative myocardial infarction, postoperative functional class, treadmill test result, and adequacy of left coronary artery revascularization), only the adequacy of left coronary artery revascularization differed between Groups N and A. Eight of 11 Group N and only three of 20 Group A patients had complete revascularization, with patent grafts, of the left coronary artery. We conclude that improved exercise hemodynamic function does occur in some patients after aorta-coronary artery bypass operations. Such improvement is most likely when all major lesions of the left coronary artery are completely revascularized.

  15. Arterial Smooth Muscle Mitochondria Amplify Hydrogen Peroxide Microdomains Functionally Coupled to L-Type Calcium Channels

    PubMed Central

    Chaplin, Nathan L.; Nieves-Cintrón, Madeline; Fresquez, Adriana M.; Navedo, Manuel F.; Amberg, Gregory C.

    2015-01-01

    Rationale Mitochondria are key integrators of convergent intracellular signaling pathways. Two important second messengers modulated by mitochondria are calcium and reactive oxygen species. To date, coherent mechanisms describing mitochondrial integration of calcium and oxidative signaling in arterial smooth muscle are incomplete. Objective To address and add clarity to this issue we tested the hypothesis that mitochondria regulate subplasmalemmal calcium and hydrogen peroxide microdomain signaling in cerebral arterial smooth muscle. Methods and Results Using an image-based approach we investigated the impact of mitochondrial regulation of L-type calcium channels on subcellular calcium and ROS signaling microdomains in isolated arterial smooth muscle cells. Our single cell observations were then related experimentally to intact arterial segments and to living animals. We found that subplasmalemmal mitochondrial amplification of hydrogen peroxide microdomain signaling stimulates L-type calcium channels and that this mechanism strongly impacts the functional capacity of the vasoconstrictor angiotensin II. Importantly, we also found that disrupting this mitochondrial amplification mechanism in vivo normalized arterial function and attenuated the hypertensive response to systemic endothelial dysfunction. Conclusions From these observations we conclude that mitochondrial amplification of subplasmalemmal calcium and hydrogen peroxide microdomain signaling is a fundamental mechanism regulating arterial smooth muscle function. As the principle components involved are fairly ubiquitous and positioning of mitochondria near the plasma membrane is not restricted to arterial smooth muscle, this mechanism could occur in many cell types and contribute to pathological elevations of intracellular calcium and increased oxidative stress associated with many diseases. PMID:26390880

  16. Application of speckle-tracking in the evaluation of carotid artery function in subjects with hypertension and diabetes.

    PubMed

    Yang, Eric Y; Brunner, Gerd; Dokainish, Hisham; Hartley, Craig J; Taffet, George; Lakkis, Nasser; Taylor, Addison A; Misra, Arunima; McCulloch, Marti L; Morrisett, Joel D; Virani, Salim S; Ballantyne, Christie M; Nagueh, Sherif F; Nambi, Vijay

    2013-08-01

    Speckle-tracking enables direct tracking of carotid arterial wall motion. Timing intervals determined with carotid speckle-tracking and slopes calculated from carotid artery area versus cardiac cycle curves may provide further information on arterial function and stiffness. The proposed arterial stiffness parameters were examined in healthy controls (n = 20), nondiabetic patients with hypertension (n = 20), and patients with type 2 diabetes (n = 21). Bilateral electrocardiographically gated ultrasonograms of the distal common carotid artery were acquired using a 12-MHz vascular probe. Four timing intervals were derived from speckle-tracked carotid arterial strain curves: (1) carotid predistension period, (2) peak carotid arterial strain time, (3) arterial distension period, and (4) arterial diastolic time. In addition, carotid artery area curves were recorded over the cardiac cycle and subdivided into four segments, S1 to S4, relating to arterial distention and contraction periods. Mean far wall predistension period and peak carotid arterial strain time were more delayed in patients with diabetes and hypertension than in controls. Global mean arterial distension period was prolonged and arterial diastolic time was shorter in patients with hypertension and diabetes than in controls. Slopes of segments S2 and S4 were markedly steeper in the combined group of patients with hypertension and diabetes compared with healthy controls (P = .03 and P = .02, respectively). Speckle-tracking-based measures of arterial stiffness may provide potential additive value in assessing vascular function in patients at risk for cardiovascular disease. Published by Mosby, Inc.

  17. Chronic Interactions Between Carotid Baroreceptors and Chemoreceptors in Obesity Hypertension.

    PubMed

    Lohmeier, Thomas E; Iliescu, Radu; Tudorancea, Ionut; Cazan, Radu; Cates, Adam W; Georgakopoulos, Dimitrios; Irwin, Eric D

    2016-07-01

    Carotid bodies play a critical role in protecting against hypoxemia, and their activation increases sympathetic activity, arterial pressure, and ventilation, responses opposed by acute stimulation of the baroreflex. Although chemoreceptor hypersensitivity is associated with sympathetically mediated hypertension, the mechanisms involved and their significance in the pathogenesis of hypertension remain unclear. We investigated the chronic interactions of these reflexes in dogs with sympathetically mediated, obesity-induced hypertension based on the hypothesis that hypoxemia and tonic activation of carotid chemoreceptors may be associated with obesity. After 5 weeks on a high-fat diet, the animals experienced a 35% to 40% weight gain and increases in arterial pressure from 106±3 to 123±3 mm Hg and respiratory rate from 8±1 to 12±1 breaths/min along with hypoxemia (arterial partial pressure of oxygen=81±3 mm Hg) but eucapnia. During 7 days of carotid baroreflex activation by electric stimulation of the carotid sinus, tachypnea was attenuated, and hypertension was abolished before these variables returned to prestimulation values during a recovery period. After subsequent denervation of the carotid sinus region, respiratory rate decreased transiently in association with further sustained reductions in arterial partial pressure of oxygen (to 65±2 mm Hg) and substantial hypercapnia. Moreover, the severity of hypertension was attenuated from 125±2 to 116±3 mm Hg (45%-50% reduction). These findings suggest that hypoxemia may account for sustained stimulation of peripheral chemoreceptors in obesity and that this activation leads to compensatory increases in ventilation and central sympathetic outflow that contributes to neurogenically mediated hypertension. Furthermore, the excitatory effects of chemoreceptor hyperactivity are abolished by chronic activation of the carotid baroreflex. © 2016 American Heart Association, Inc.

  18. Polygenic overlap between kidney function and large artery atherosclerotic stroke.

    PubMed

    Holliday, Elizabeth G; Traylor, Matthew; Malik, Rainer; Bevan, Stephen; Maguire, Jane; Koblar, Simon A; Sturm, Jonathan; Hankey, Graeme J; Oldmeadow, Christopher; McEvoy, Mark; Sudlow, Cathie; Rothwell, Peter M; Coresh, Josef; Hamet, Pavel; Tremblay, Johanne; Turner, Stephen T; de Andrade, Mariza; Rao, Madhumathi; Schmidt, Reinhold; Crick, Peter A; Robino, Antonietta; Peralta, Carmen A; Jukema, J Wouter; Mitchell, Paul; Rosas, Sylvia E; Wang, Jie Jin; Scott, Rodney J; Dichgans, Martin; Mitchell, Braxton D; Kao, W H Linda; Fox, Caroline S; Levi, Christopher; Attia, John; Markus, Hugh S

    2014-12-01

    Epidemiological studies show strong associations between kidney dysfunction and risk of ischemic stroke (IS), the mechanisms of which are incompletely understood. We investigated whether these associations may reflect shared heritability because of a common polygenic basis and whether this differed for IS subtypes. Polygenic models were derived using genome-wide association studies meta-analysis results for 3 kidney traits: estimated glomerular filtration rate using serum creatinine (eGFRcrea: n=73 998), eGFR using cystatin C (eGFRcys: n=22 937), and urinary albumin to creatinine ratio (n=31 580). For each, single nucleotide polymorphisms passing 10 P value thresholds were used to form profile scores in 4561 IS cases and 7094 controls from the United Kingdom, Germany, and Australia. Scores were tested for association with IS and its 3 aetiological subtypes: large artery atherosclerosis, cardioembolism, and small vessel disease. Polygenic scores correlating with higher eGFRcrea were associated with reduced risk of large artery atherosclerosis, with 5 scores reaching P<0.05 (peak P=0.004) and all showing the epidemiologically expected direction of effect. A similar pattern was observed for polygenic scores reflecting higher urinary albumin to creatinine ratio, of which 3 associated with large artery atherosclerosis (peak P=0.01) and all showed the expected directional association. One urinary albumin to creatinine ratio-based score also associated with small vessel disease (P=0.03). The global pattern of results was unlikely to have occurred by chance (P=0.02). This study suggests possible polygenic correlation between renal dysfunction and IS. The shared genetic components may be specific to stroke subtypes, particularly large artery atherosclerotic stroke. Further study of the genetic relationships between these disorders seems merited. © 2014 American Heart Association, Inc.

  19. Effects of Renal Denervation on Renal Artery Function in Humans: Preliminary Study

    PubMed Central

    Doltra, Adelina; Hartmann, Arthur; Stawowy, Philipp; Goubergrits, Leonid; Kuehne, Titus; Wellnhofer, Ernst; Gebker, Rolf; Schneeweis, Christopher; Schnackenburg, Bernhard; Esler, Murray; Fleck, Eckart; Kelle, Sebastian

    2016-01-01

    Aim To study the effects of RD on renal artery wall function non-invasively using magnetic resonance. Methods and Results 32 patients undergoing RD were included. A 3.0 Tesla magnetic resonance of the renal arteries was performed before RD and after 6-month. We quantified the vessel sharpness of both renal arteries using a quantitative analysis tool (Soap-Bubble®). In 17 patients we assessed the maximal and minimal cross-sectional area of both arteries, peak velocity, mean flow, and renal artery distensibility. In a subset of patients wall shear stress was assessed with computational flow dynamics. Neither renal artery sharpness nor renal artery distensibility differed significantly. A significant increase in minimal and maximal areas (by 25.3%, p = 0.008, and 24.6%, p = 0.007, respectively), peak velocity (by 16.9%, p = 0.021), and mean flow (by 22.4%, p = 0.007) was observed after RD. Wall shear stress significantly decreased (by 25%, p = 0.029). These effects were observed in blood pressure responders and non-responders. Conclusions RD is not associated with adverse effects at renal artery level, and leads to an increase in cross-sectional areas, velocity and flow and a decrease in wall shear stress. PMID:27003912

  20. MR and CT imaging of the structural and functional changes of pulmonary arterial hypertension

    PubMed Central

    Schiebler, Mark L.; Bhalla, Sanjeev; Runo, James; Jarjour, Nizar; Roldan, Alejandro; Chesler, Naomi; François, Christopher J.

    2013-01-01

    The current Dana Point classification system (2009) divides elevation of pulmonary artery pressure into Pulmonary Arterial Hypertension (PAH) and Pulmonary Hypertension (PH). Fortunately, pulmonary arterial hypertension (PAH) is not a common disease. However, with the aging of the first world’s population, heart failure is now an important cause of pulmonary hypertension with up to 9% of the population involved. PAH is usually asymptomatic until late in the disease process. While there are indirect features of PAH found on noninvasive imaging studies, the diagnosis and management still requires right heart catheterization. Imaging features of PAH include: 1. Enlargement of the pulmonary trunk and main pulmonary arteries, 2. Decreased pulmonary arterial compliance, 3. Tapering of the peripheral pulmonary arteries, 4. Enlargement of the inferior vena cava, and 5. Increased mean transit time. The chronic requirement to generate high pulmonary arterial pressures measurably affects the right heart and main pulmonary artery. This change in physiology causes the following structural and functional alterations that have been shown to have prognostic significance: Relative area change of the pulmonary trunk, RVSVindex, RVSV, RVEDVindex, LVEDVindex, and baseline RVEF <35%. All of these variables can be quantified non-invasively and followed longitudinally in each patient using MRI to modify the treatment regimen. Untreated PAH frequently results in a rapid clinical decline and death within 3 years of diagnosis. Unfortunately, even with treatment, less than 1/2 of these patients are alive at four years. PMID:23612440

  1. Vascular Function and Intima-media Thickness of a Leg Artery in Peripheral Artery Disease: A Comparison of Buerger Disease and Atherosclerotic Peripheral Artery Disease.

    PubMed

    Iwamoto, Akimichi; Kajikawa, Masato; Maruhashi, Tatsuya; Iwamoto, Yumiko; Oda, Nozomu; Kishimoto, Shinji; Matsui, Shogo; Kihara, Yasuki; Chayama, Kazuaki; Goto, Chikara; Noma, Kensuke; Aibara, Yoshiki; Nakashima, Ayumu; Higashi, Yukihito

    2016-11-01

    Both vascular function and structure are independent predictors of cardiovascular events. The purpose of this study was to evaluate vascular function and structure of a leg artery in patients with peripheral artery disease (PAD). We measured flow-mediated vasodilatation (FMD) and nitroglycerine-induced vasodilation (NID) as indices of vascular function and intima-media thickness (IMT) as an index of vascular structure of the popliteal artery in 100 subjects, including 20 patients with Buerger disease and 30 patients with atherosclerotic PAD, 20 age- and sex-matched subjects without Buerger disease (control group) and 30 age- and sex-matched patients without atherosclerotic PAD (control group). IMT was significantly larger in the Buerger group than in the control group (Buerger, 0.63± 0.20 mm; control, 0.50±0.07 mm; P=0.01), whereas there were no significant differences in FMD and NID between the two groups. IMT was significantly larger in the atherosclerotic PAD group than in the control group (atherosclerotic PAD, 0.80±0.22 mm; control, 0.65±0.14 mm; P<0.01), and FMD and NID were significantly smaller in the atherosclerotic PAD group than in the control group (FMD: atherosclerotic PAD, 3.9%±1.1%; control, 5.0%±1.8%; P<0.01; and NID: atherosclerotic PAD, 6.1%±2.0%; control, 8.4%±2.1%; P<0.01). These findings suggest that vascular function is preserved in patients with Buerger disease and that both vascular function and vascular structure are impaired in patients with atherosclerotic PAD.

  2. H(1) and H(2) receptors in the locus ceruleus are involved in the intracerebroventricular histamine-induced carotid sinus baroreceptor reflex resetting in rats.

    PubMed

    Wang, Guo-Qing; Sun, Wan-Ping; Zhu, Yong-Jin; Zou, Rong; Zhou, Xi-Ping

    2006-07-01

    Objective To investigate the role of H(1) and H(2) receptors in the locus ceruleus (LC) in carotid sinus baroreceptor reflex (CSR) resetting induced by intracerebroventricular (i.c.v.) injection of histamine (HA). Methods The left and right carotid sinus regions were isolated from the systemic circulation in 18 male Sprague-Dawley rats anesthetized with pentobarbital sodium. The intracarotid sinus pressure (ISP) was altered in a stepwise manner in vivo. ISP-mean arterial pressure (MAP) relationship curve and its characteristic parameters were constructed by fitting to the logistic function with five parameters. The changes in CSR performance induced by i.c.v. HA and the effects of pretreatment with H(1) or H(2) receptors selective antagonist, chlorpheniramine (CHL) or cimetidine (CIM) into the LC, on the responses of CSR to HA were examined. Results I.c.v. HA (100 ng in 5 mu l) significantly shifted the ISP-MAP relationship curve upwards (P < 0.05) and obviously decreased the value of the reflex parameters such as MAP range and maximum gain (P < 0.05), but increased the threshold pressure, saturation pressure and ISP at maximum gain (P < 0.05). The pretreatment with CHL (0.5 mu g in 1 mu l) or CIM (1.5 mu g in 1 mu l) into the LC could obviously attenuate the changes mentioned above in CSR performance induced by HA, but the alleviative effect of CIM was less remarkable than that of CHL (P < 0.05). Respective microinjection of CHL or CIM alone into the LC with the corresponding dose and volume did not change CSR performance significantly (P > 0.05). Conclusion Intracerebroventricular administration of HA results in a rapid resetting of CSR and a decrease in reflex sensitivity, and the responses of CSR to HA may be mediated, at least in part, by H(1) and H(2) receptors activities in the LC, especially by H(1) receptors. Moreover, the effects of the central HA on CSR might be related to a histaminergic descending pathway from the hypothalamus to LC.

  3. Arterial stiffness, body fat compartments, central hemodynamics, renal function and left atrial size.

    PubMed

    Katulska, Katarzyna; Milewska, Agata; Wykretowicz, Mateusz; Krauze, Tomasz; Przymuszala, Dagmara; Piskorski, Jaroslaw; Stajgis, Marek; Guzik, Przemyslaw; Wysocki, Henryk; Wykrętowicz, Andrzej

    2013-10-01

    Left atrial (LA) size is an important predictor of stroke, death, and atrial fibrillation. It was demonstrated recently that body fat, arterial stiffness and renal functions are associated with LA diameter. However, data are lacking for comprehensive assessments of all these risk factors in a single population. Therefore, the aim of the present study was to investigate the association between LA size and different fat descriptors, central hemodynamics, arterial stiffness, and renal function in healthy subjects. To this end, body fat percentage, abdominal, subcutaneous fat, and general descriptors of body fat were estimated in 162 healthy subjects (mean age 51 years). Echocardiography was performed to assess LA diameter. Arterial stiffness and peripheral and central hemodynamics were estimated by digital volume pulse analysis and pulse wave analysis. Glomerular filtration rate was estimated by MDRD formula. There were significant (p < 0.05) bivariate correlations between LA diameter and all descriptors of body fat (except subcutaneous fat). Arterial stiffness and estimated glomerular filtration rate (eGFR) were also significantly correlated with LA size. Multiple regression analysis including all significant confounders, such as sex, mean arterial pressure, arterial stiffness, eGFR and body fat descriptors, explained 35% of variance in LA diameter. In conclusion, the present study reveals significant, independent relationships between body fat, arterial stiffness, and LA size.

  4. Device for rapid quantification of human carotid baroreceptor-cardiac reflex responses

    NASA Technical Reports Server (NTRS)

    Sprenkle, J. M.; Eckberg, D. L.; Goble, R. L.; Schelhorn, J. J.; Halliday, H. C.

    1986-01-01

    A new device has been designed, constructed, and evaluated to characterize the human carotid baroreceptor-cardiac reflex response relation rapidly. This system was designed for study of reflex responses of astronauts before, during, and after space travel. The system comprises a new tightly sealing silicon rubber neck chamber, a stepping motor-driven electrodeposited nickel bellows pressure system, capable of delivering sequential R-wave-triggered neck chamber pressure changes between +40 and -65 mmHg, and a microprocessor-based electronics system for control of pressure steps and analysis and display of responses. This new system provokes classic sigmoid baroreceptor-cardiac reflex responses with threshold, linear, and saturation ranges in most human volunteers during one held expiration.

  5. [Improved methods for researching isolated carotid sinus baroreceptors automatically controlling for sinus pressure].

    PubMed

    Wei, Hua; Zhao, Hai-Yan; Liu, Ping; Huang, Hai-Xia; Wang, Wei; Fu, Xiao-Suo; Niu, Wei-Zhen

    2013-01-01

    To develop a system for automatically controlling carotid sinus pressure in the study on baroreceptors. The preparation containing carotid sinus with parts of the connected vessels and carotid sinus nerve (CS-CSN) were isolated and perfused. A critical pressure controlling component (PRE-U, Hoerbiger, Deutschland) dictated by a computer was integrated into the system to clamp the intrasinus pressure. The pressure command and the relevant intrasinus pressure were compared to evaluate the validity of the pressure controlling system. A variety of sinus pressure-controlling patterns, including pulsation, ramp and step pressures, could be achieved accurately by using the system, and the pressure-dependent discharge activities of sinus nerve were confirmed. This system for clamping carotid sinus pressure could realize multiple pressure-controlling patterns and is a useful and flexible pressure controlling method that could applied in the study on mechano-electric transduction of baroreceptors.

  6. Periodic posture stimulation of the baroreceptors and the local vasomotor reflexes.

    PubMed

    Nasimi, S G; Harness, J B; Marjanović, D Z; Knight, T; Mearns, A J

    1992-07-01

    In a supine subject, lowering of the foot from heart level to 50 cm below is known to stimulate the local reflex response and the baroreceptor outflow. We lowered and raised the leg of a supine subject periodically, with the leg stationary between movements (square wave). The Traube-Hering-Mayer wave (THM congruent to 0.1 Hz) was captured by or locked on to the leg movement over a certain frequency range, this is usually called the entrainment range. Square wave periodic leg movement in this manner on 10 male subjects, mean age 22 years, demonstrated that the THM frequency can be entrained. The lower limit of the entrainment bandwidth is 0.0841 (SD 0.0030) Hz and the upper limit is 0.1176 (SD 0.0013) Hz. Further examination showed that this phenomenon is independent of the breathing input. Comparison with the Traube-Hering-Mayer entrainment techniques of breathing and periodic neck suction using the Eckberg collar which stimulates the baroreceptors showed similar results. This work supports the hypothesis that the local reflex response and the baroreceptor outflow entrain the THM frequency.

  7. Visceral and Subcutaneous Adiposity and Brachial Artery Vasodilator Function

    PubMed Central

    Parikh, Nisha I.; Keyes, Michelle J.; Larson, Martin G.; Pou, Karla M.; Hamburg, Naomi M.; Vita, Joseph A.; O'Donnell, Christopher J.; Vasan, Ramachandran S.; Mitchell, Gary F.; Hoffmann, Udo; Fox, Caroline S.; Benjamin, Emelia J.

    2011-01-01

    Endothelial dysfunction may link obesity to cardiovascular disease (CVD). We tested the hypothesis that visceral abdominal tissue (VAT) as compared with subcutaneous abdominal tissue (SAT) is more related to endothelium-dependent vasodilation. Among Framingham Offspring and Third Generation cohorts (n=3020, mean age 50 years, 47% women) We used multivariable linear regression adjusted for CVD and its risk factors to relate computed tomography-assessed VAT and SAT, body mass index (BMI) and waist circumference (WC), with brachial artery measures. In multivariable-adjusted models, BMI, WC, VAT and SAT were positively related to baseline artery diameter and baseline mean flow velocity (all p<0.001), but not hyperemic mean flow velocity. In multivariable-adjusted models, BMI (p=0.002), WC (p=0.001) and VAT (p=0.01), but not SAT (p=0.24) were inversely associated with FMD%. However there was little incremental increase in the proportion of variability explained by VAT (R2=0.266) as compared to SAT (R2=0.265), above and beyond traditional risk factors. VAT, but not SAT was associated with FMD% after adjusting for clinical covariates. Nevertheless, the differential association with VAT as compared to SAT was minimal. PMID:19282819

  8. Growth hormone (GH) and atherosclerosis: changes in morphology and function of major arteries during GH treatment.

    PubMed

    Pfeifer, M; Verhovec, R; Zizek, B

    1999-04-01

    Patients with hypopituitarism have increased carotid artery intima-media thickness and reduced arterial distensibility. The effect of 2 years of growth hormone (GH) replacement therapy on these parameters was studied in 11 GH-deficient men (age range, 24-49 years) with hypopituitarism and compared with 12 healthy, age-matched men with no evidence of pituitary or vascular disease. Before treatment the intima-media of the common carotid arteries and the carotid bifurcations were significantly thicker in patients (P < 0.001) than in the control group. Treatment with GH normalized the intima-media thickness of the common carotid artery within 6 months and of the carotid bifurcation within 3 months. The changes in intima-media thickness of the carotid artery were negatively correlated with changes in serum levels of insulin-like growth factor I during treatment. There was a significant improvement in flow-mediated, endothelium-dependent dilation of the brachial artery at 3 months, which was sustained at 6, 18 and 24 months of GH treatment (P < 0.05). Thus, GH replacement therapy in GH-deficient men reverses early morphological and functional atherosclerotic changes in major arteries, and may reduce rates of vascular morbidity and mortality.

  9. Effect of dark chocolate on arterial function in healthy individuals: cocoa instead of ambrosia?

    PubMed

    Vlachopoulos, Charalambos; Alexopoulos, Nikolaos; Stefanadis, Christodoulos

    2006-06-01

    Cocoa has been consumed for at least 2500 years, and for long time it has been regarded as a medicine. Arterial function is of paramount importance for the proper function and integrity of the cardiovascular system. Dark chocolate and flavonoid-rich cocoa have beneficial acute and short-term effects on endothelial function and wave reflections in normal individuals, in adults with cardiovascular risk factors, and in patients with coronary artery disease. Furthermore, dark chocolate and flavonoid-rich cocoa may have a blood pressure-lowering effect. These effects can be attributed to flavonoids and are mainly mediated through increased nitric oxide bioavailability. Further research is needed to demonstrate whether these effects of chocolate on arterial function are translated into clinical benefit.

  10. Application of Nexfin noninvasive beat-to-beat arterial blood pressure monitoring in autonomic function testing.

    PubMed

    Sipkens, Laura M; Treskes, Kaij; Ariese-Beldman, Karin; Veerman, Derk P; Boer, Christa

    2011-10-01

    Evaluation of autonomic function responses is increasingly important for risk prediction and hemodynamic evaluation in the ambulant and perioperative setting, but requires a noninvasive arterial blood pressure measurement device. This study describes whether a novel noninvasive beat-to-beat arterial blood pressure measurement device (Nexfin HD) is able to reproducibly reflect autonomic function responses in healthy volunteers. Noninvasive beat-to-beat arterial blood pressure measurements (Nexfin HD) were performed in 20 healthy men of 22 ± 3 years. Measurements were performed during supine steady state, controlled breathing (0.125 Hz), passive leg raising, a controlled Valsalva maneuver, and a quick stand test. Finally, relative changes in pulse pressure during autonomic function testing and the test-retest reproducibility were determined. Autonomic function tests induced beat-to-beat arterial blood pressure changes that were accurately monitored by the Nexfin device. The intraclass correlation coefficients for systolic and diastolic arterial blood pressure measurements during supine steady state were agreeable [0.91 (0.82-0.96) and 0.84 (0.69-0.93), respectively]. The reproducibility of blood pressure changes during controlled breathing, passive leg raising, and Valsalva maneuver averaged 0.92 (0.82-0.96), 0.76 (0.50-0.90), and 0.94 (0.89-0.97), respectively. The reproducibility of the pulse pressure variation (PPV) as calculated from controlled breathing-induced changes in the arterial blood pressure (13 ± 5%) was high [0.96 (0.93-0.98)]. This study shows that noninvasive beat-to-beat Nexfin HD arterial blood pressure measurements reproducibly reflect autonomic function responses in healthy volunteers.

  11. Non-voltage-gated Ca2+ influx through mechanosensitive ion channels in aortic baroreceptor neurons.

    PubMed

    Sullivan, M J; Sharma, R V; Wachtel, R E; Chapleau, M W; Waite, L J; Bhalla, R C; Abboud, F M

    1997-06-01

    The mechanisms underlying mechanotransduction in baroreceptor neurons (BRNs) are undefined. In this study, we specifically identified aortic baroreceptor neurons in primary neuronal cell cultures from nodose ganglia of rats. Aortic baroreceptor neurons were identified by labeling their soma with the fluorescent dye 1,1'-dioleyl-3,3,3',3'-tetramethylin-docarbocyanine (DiI) applied to the aortic arch. Using Ca2+ imaging with fura 2, we examined these BRNs for evidence of Ca2+ influx and determined its mechanosensitivity and voltage dependence. Mechanical stimuli were produced by ejecting buffer from a micropipette onto the cell surface with a pneumatic picopump, producing a shift in the center of mass of the cell that was related to intensity of stimulation. Ninety-three percent of DiI-labeled neurons responded to mechanical stimulation with an increase in [Ca2+]i. The magnitude of the increases in [Ca2+]i was directly related to the intensity of the stimulus and required the presence of external Ca2+. The trivalent cations Gd3+ or La3+ in equimolar concentrations (20 mumol/L) eliminated the K(+)-induced rises in [Ca2+]i, demonstrating that both trivalent cations are equally effective at blocking voltage-gated Ca2+ channels in these baroreceptor neurons. In contrast, the mechanically induced increases in [Ca2+]i were blocked by Gd3+ (20 mumol/L) only and not by La3+ (20 mumol/L). Stretch-activated channels (SACs) have been shown in other preparations to be blocked by Gd3+ specifically. Our data demonstrate that (1) BRNs, specifically identified as projecting to the aortic arch, have ion channels that are sensitive to mechanical stimuli; (2) mechanically induced Ca2+ influx in these cells is mediated by a Gd(3+)-sensitive ion channel and not by voltage-gated Ca2+ channels; (3) the magnitude of the Ca2+ influx is dependent on the intensity of the stimulus and the degree and duration of deformation; and (4) repeated stimuli of the same intensity result in comparable

  12. Baroreflex function in anurans from different environments.

    PubMed

    Hedrick, Michael S; McNew, Kadi A; Crossley, Dane A

    2015-01-01

    Anurans from terrestrial environments have an enhanced ability to maintain mean arterial blood pressure (P(m)) through lymph mobilization in response to desiccation or hemorrhage compared with semiaquatic or aquatic species. Because short term blood pressure homeostasis is regulated by arterial baroreceptors, we compared baroreflex function in three species of anurans that span a range of environments, dehydration tolerance and an ability to maintain P(m) with dehydration and hemorrhage. The cardiac limb of the baroreflex loop was studied using pharmacological manipulation of P(m) with phenylephrine and sodium nitroprusside (20–200 μg kg(− 1)), and the resulting changes in heart rate (f(H)) were quantitatively analyzed using a four-parameter sigmoidal logistic function. Resting P(m) in the aquatic species, Xenopus laevis, was 3.6 ± 0.3 kPa and was significantly less (P < 0.005) than for the semiaquatic species, Lithobates catesbeianus (4.1 ± 0.2 kPa), or the terrestrial species, Rhinella marina (4.7 ± 0.2 kPa). The maximal baroreflex gain was not different among the three species and ranged from 12.1 to 14.3 beats min( −1) kPa( −1) and occurred at P(m )ranging from 3.0 to 3.8 kPa, which were slightly below the resting P(m) for each species. Mean arterial blood pressures at rest in the three species were near the saturation point of the baroreflex curve which provides the animals with a greater fH response range to hypotensive, rather than hypertensive, changes in P(m). This is consistent with the hypothesis that arterial baroreceptors are key sensory components that allow anurans to maintain P(m) possibly by mobilization of lymphatic return in response to hypotension.

  13. Age-associated Pro-inflammatory Remodeling and Functional Phenotype in the Heart and Large Arteries

    PubMed Central

    Wang, Mingyi; Shah, Ajay M

    2015-01-01

    The aging population is increasing dramatically. Aging–associated stress simultaneously drives proinflammatory remodeling, involving angiotensin II and other factors, in both the heart and large arteries. The structural remodeling and functional changes that occur with aging include cardiac and vascular wall stiffening, systolic hypertension and suboptimal ventricular-arterial coupling, features that are often clinically silent and thus termed a silent syndrome. These age-related effects are the result of responses initiated by cardiovascular proinflammatory cells. Local proinflammatory signals are coupled between the heart and arteries due to common mechanical and humoral messengers within a closed circulating system. Thus, targeting proinflammatory signaling molecules would be a promising approach to improve age-associated suboptimal ventricular-arterial coupling, a major predisposing factor for the pathogenesis of clinical cardiovascular events such as heart failure. PMID:25665458

  14. Effects of cranberry juice consumption on vascular function in patients with coronary artery disease

    USDA-ARS?s Scientific Manuscript database

    Cranberry juice contains polyphenolic compounds that could improve endothelial function and reduce cardiovascular disease risk. The objective was to examine the effects of cranberry juice on vascular function in subjects with coronary artery disease. We completed an acute pilot study with no placebo...

  15. Polygenic overlap between kidney function and large artery atherosclerotic stroke

    PubMed Central

    Holliday, Elizabeth G.; Traylor, Matthew; Malik, Rainer; Bevan, Stephen; Maguire, Jane; Koblar, Simon A.; Sturm, Jonathan; Hankey, Graeme J.; Oldmeadow, Christopher; McEvoy, Mark; Sudlow, Cathie; Rothwell, Peter M.; Coresh, Josef; Hamet, Pavel; Tremblay, Johanne; Turner, Stephen T.; de Andrade, Mariza; Rao, Madhumathi; Schmidt, Reinhold; Crick, Peter A.; Robino, Antonietta; Peralta, Carmen A.; Jukema, J. Wouter; Mitchell, Paul; Rosas, Sylvia E.; Wang, Jie Jin; Scott, Rodney J.; Dichgans, Martin; Mitchell, Braxton D.; Linda Kao, W. H.; Fox, Caroline S.; Levi, Christopher; Attia, John; Markus, Hugh S

    2014-01-01

    Background and Purpose Epidemiological studies show strong associations between kidney dysfunction and risk of ischaemic stroke, the mechanisms of which are incompletely understood. We investigated whether these associations may reflect shared heritability due to a common polygenic basis and whether this differed for ischaemic stroke subtypes. Methods Polygenic models were derived using GWAS meta-analysis results for three kidney traits: estimated glomerular filtration rate using serum creatinine (eGFRcrea: N=73,998), eGFR using cystatin C (eGFRcys: N=22,937) and urinary albumin to creatinine ratio (UACR: N=31,580). For each, SNPs passing ten P-value thresholds were used to form profile scores in 4,561 ischaemic stroke cases and 7,094 controls from the UK, Germany and Australia. Scores were tested for association with ischaemic stroke and its three aetiological subtypes: large artery atherosclerosis (LAA), cardioembolism (CE) and small vessel disease (SVD). Results Polygenic scores correlating with higher eGFRcrea were associated with reduced risk of LAA, with five scores reaching P<0.05 (peak P=0.004) and all showing the epidemiologically expected direction of effect. A similar pattern was observed for polygenic scores reflecting higher UACR, of which three associated with LAA (peak P=0.01) and all showed the expected directional association. One UACR-based score also associated with SVD (P=0.03). The global pattern of results was unlikely to have occurred by chance (P=0.02). Conclusions This study suggests possible polygenic correlation between renal dysfunction and ischaemic stroke. The shared genetic components may be specific to stroke subtypes, particularly large artery atherosclerotic stroke. Further study of the genetic relationships between these disorders appears merited. PMID:25352485

  16. In vitro function of porcine carotid arteries preserved in UW, HTK and Celsior solutions.

    PubMed

    Abrahamse, S T L; Dinant, S; Pfaffendorf, M; van Gulik, T M

    2002-12-01

    We compared the efficacy of histidine-tryptophan-ketoglutarate (HTK) and University of Wisconsin (UW) solution with Celsior solution using hypothermically-preserved porcine carotid arteries and studied the importance of different components of these solutions by preserving carotid arteries in modified HTK solutions. Excised carotid arteries were stored at 4 degrees C in 0.9% (w/v) NaCl, UW, HTK, Celsior, or a modified HTK solution for up to 14 days. Preservation-induced changes in smooth muscle cell and endothelial cell function were determined using an organ bath for isometric tension recording. Short-term preservation (1-3 days) in UW, HTK and Celsior did not significantly alter contractile and relaxation responses of arterial segments when compared to freshly-excised segments, but significantly impaired these responses in arterial segments stored in 0.9% (w/v) NaCl solution. Long-term hypothermic preservation of arterial segments (7 and 14 days) in 0.9% (w/v) NaCl and HTK solution almost completely abolished all responses, but only slightly reduced the responses of arterial segments stored in UW solution. Intermediate results were obtained for Celsior. Modifying HTK by replacement of chloride for sulfate and phosphate resulted in improved contractile and relaxation responses after long-term preservation. With respect to smooth muscle and endothelial function, UW is superior to HTK and Celsior and the absence of chloride or presence of sulfate and phosphate plays a relevant role in this in vitro model of hypothermic preservation of porcine carotid arteries.

  17. Left ventricular function during lower body negative pressure

    NASA Technical Reports Server (NTRS)

    Ahmad, M.; Blomqvist, C. G.; Mullins, C. B.; Willerson, J. T.

    1977-01-01

    The response of the human left ventricle to lower body negative pressure (LBNP) and the relation between left ventricular function and hemodynamic response were investigated. Ventricular function curves relating stroke volume to end-diastolic volume were obtained in 12 normal men. Volume data were derived from echocardiographic measurements of left ventricular end-systolic and end-diastolic diameters at rest and during lower body negative pressure (LBNP) at minus 40 mm Hg. End-diastolic volume decreased by 19% and stroke volume by 22%. There were no significant changes in heart rate, arterial blood pressure, or end-systolic volume. Thus, moderate levels of LBNP significantly reduce preload and stroke volume without affecting contractile state. The absence of significant changes in heart rate and arterial blood pressure in the presence of a significant reduction in stroke volume is consistent with an increase in systemic peripheral resistance mediated by low-pressure baroreceptors.

  18. Effect of posture on arterial baroreflex control of heart rate in humans

    NASA Technical Reports Server (NTRS)

    Harrison, M. H.; Rittenhouse, D.; Greenleaf, J. E.

    1986-01-01

    The effects of blood-volume redistribution induced by postural changes on baroreflex activity are investigated. The central blood volume and baroreceptor functions of ten males between 23-51 years old were examined while they were in the head-up tilt (HUT), head-down tilt (HDT), and supine positions. It is observed that during HDT at 15 deg the pulse interval over the first five cardiac cycles following neck suction onset is 51 + or - 18 ms longer, at 30 deg it is 61 + or - 20 ms longer, and at 45 deg it is 74 + or - 35 ms longer than at supine; during HUT at 15 deg the pulse interval is 25 + or - 9 ms shorter than when supine, but for the 30 and 45 deg there is no significant difference in pulse interval detected. The data reveal that posture does modify arterial baroreflex control of heart rate.

  19. Effect of posture on arterial baroreflex control of heart rate in humans

    NASA Technical Reports Server (NTRS)

    Harrison, M. H.; Rittenhouse, D.; Greenleaf, J. E.

    1986-01-01

    The effects of blood-volume redistribution induced by postural changes on baroreflex activity are investigated. The central blood volume and baroreceptor functions of ten males between 23-51 years old were examined while they were in the head-up tilt (HUT), head-down tilt (HDT), and supine positions. It is observed that during HDT at 15 deg the pulse interval over the first five cardiac cycles following neck suction onset is 51 + or - 18 ms longer, at 30 deg it is 61 + or - 20 ms longer, and at 45 deg it is 74 + or - 35 ms longer than at supine; during HUT at 15 deg the pulse interval is 25 + or - 9 ms shorter than when supine, but for the 30 and 45 deg there is no significant difference in pulse interval detected. The data reveal that posture does modify arterial baroreflex control of heart rate.

  20. The effects of acute hypobaric hypoxia on arterial stiffness and endothelial function and its relationship to changes in pulmonary artery pressure and left ventricular diastolic function.

    PubMed

    Boos, C J; Hodkinson, P; Mellor, A; Green, N P; Woods, D R

    2012-06-01

    This study investigated, for the first time, the effects of simulated high altitude, following acute hypobaric hypoxia (HH), on simultaneous assessment of large artery stiffness and endothelial function and its inter-relationship to left ventricular (LV) diastolic function, pulmonary artery systolic pressure (PASP), and estimated PA vascular resistance (PVR). Ten healthy subjects were studied at baseline pre and following acute HH to 4800 m for a total of 180 minutes. Assessments of LV diastolic function, mitral inflow, estimated LV filling pressure (E/e'), PVR, and PASP were undertaken using transthoracic echocardiography. Simultaneous assessments of arterial stiffness index (SI), systemic vascular resistance (SVR), vascular tone, and endothelial function (reflective index [RI]) were performed using pulse contour analysis of the digital arterial waveform. Acute hypoxia led to a fall in SpO₂ (98.1±0.7 vs. 71.8±7.1%; p=0.0002), SVR (1589.1±191.2 vs. 1187.8±248.7; p=0.004), and RI (50.8±10.3 vs. 33.0±6.5%; p=0.0008) with an increase in PASP (24.3±2.2 to 35.0±5.3 mmHg; p=0.0001) and estimated PVR (116.40±19.0 vs. 144.6±21.5; p<0.001). There was no rise in either SI (p=0.13), mitral early annular early e' filling velocity or E/e'. There was a significant inverse correlation between SpO₂ and PASP (r=-0.77; p<0.0001), PVR (r=-0.57; p=0.008) and between the fall in SpO₂ and change (Δ) in RI (baseline vs. 150 min, r=-0.52; p<0.001). There was a modest inverse correlation between ΔRI (lower ΔRI=worsening endothelial function) and ΔPAP (r=-0.55; p=0.10) and a strong inverse correlation between ΔRI and ΔPVR (r=-0.89; p=0.0007). Acute hypobaric hypoxia does not significantly alter large artery stiffness or cause overt LV diastolic function. However, the degree of hypoxia influences both the systemic endothelial and pulmonary vascular responses. This noted association is intriguing and requires further investigation.

  1. Protocadherin-12 deficiency leads to modifications in the structure and function of arteries in mice.

    PubMed

    Philibert, C; Bouillot, S; Huber, P; Faury, G

    2012-02-01

    We studied the role of protocadherin-12 on arterial function. This protein belongs to the cadherin superfamily and is located at the intercellular junctions of endothelial cells where it promotes homotypic cellular adhesion. We previously showed that mice deficient for PCDH12 exhibited developmental growth retardation owing to placenta defects without altering neither survival nor fertility. Here, we investigated the effects of PCDH12 deficiency on the structural, mechanical properties and functionality of arteries from adult mice. Histological studies of the PCDH12(-/-) mouse arteries have shown age-independent modifications such as ramifications of medial elastic lamellae, accompanied by the appearance of radial fibers linking together two successive concentric elastic lamellae. Mechanical studies also revealed some age-independent modifications in the PCDH12(-/-) mice arteries such as an increase in inner-diameter and circumferential mid-wall stress. Moreover, the PCDH12(-/-) mice exhibited a mild reduction of blood pressure, thus maintaining the inner-diameter close to its normal value and a normal circumferential wall stress for vascular cells. This is likely a compensation mechanism enabling normal blood flow in the arteries. The vascular phenotypic differences observed between PCDH12(-/-) and wild type mice arteries did not seem to be age-dependent, except for some results regarding the carotid artery: the reactivity to acetylcholine and the circumferential mid-wall stress decreased with ageing in the PCDH12(-/-) mice, as opposed to the increase observed in the wild types. In conclusion, deficiency in one specific interendothelial junction component leads to significant changes in the structure and function of the vascular wall. Possible explanations for the observed modifications are discussed.

  2. Binding and functional pharmacological characteristics of gepant-type antagonists in rat brain and mesenteric arteries.

    PubMed

    Sheykhzade, Majid; Amandi, Nilofar; Pla, Monica Vidal; Abdolalizadeh, Bahareh; Sams, Anette; Warfvinge, Karin; Edvinsson, Lars; Pickering, Darryl S

    2017-03-01

    The neuropeptide calcitonin gene-related peptide (CGRP) is found in afferent sensory nerve fibers innervating the resistance arteries and plays a pivotal role in a number of neurovascular diseases such as migraine and subarachnoid bleedings. The present study investigates the binding and antagonistic characteristics of small non-peptide CGRP receptor antagonists (i.e. gepants) in isolated rat brain and mesenteric resistance arteries. The antagonistic behavior of gepants was investigated in isolated rat mesenteric arteries using a wire myograph setup while binding of gepants to CGRP receptors was investigated in rat brain membranes using a radioligand competitive binding assay. Furthermore, the histological location of the key components of CGRP receptor (RAMP1 and CLR) was assessed by immunohistochemistry. Our functional studies clearly show that all gepants are reversible competitive antagonists producing Schild plot slopes not significantly different from unity and thus suggesting presence of a uniform CGRP receptor population in the arteries. A uniform receptor population was also confirmed by radioligand competitive binding studies showing similar affinities for the gepants in rat brain and mesenteric arteries, the exception being rimegepant which had 50-fold lower affinity in brain than mesenteric arteries. CLR and RAMP1 were shown to be located in both vascular smooth muscle and endothelial cells of rat mesenteric arteries by immunohistochemistry. The present results indicate that, despite species differences in the CGRP receptor affinity, the antagonistic nature of these gepants, the distribution pattern of CGRP receptor components and the mechanism behind CGRP-induced vasodilation seem to be similar in resistance-sized arteries of human and rats. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Oral trehalose supplementation improves resistance artery endothelial function in healthy middle-aged and older adults

    PubMed Central

    Kaplon, Rachelle E.; Hill, Sierra D.; Bispham, Nina Z.; Santos-Parker, Jessica R.; Nowlan, Molly J.; Snyder, Laura L.; Chonchol, Michel; LaRocca, Thomas J.; McQueen, Matthew B.; Seals, Douglas R.

    2016-01-01

    We hypothesized that supplementation with trehalose, a disaccharide that reverses arterial aging in mice, would improve vascular function in middle-aged and older (MA/O) men and women. Thirty-two healthy adults aged 50-77 years consumed 100 g/day of trehalose (n=15) or maltose (n=17, isocaloric control) for 12 weeks (randomized, double-blind). In subjects with Δbody mass<2.3kg (5 lb.), resistance artery endothelial function, assessed by forearm blood flow to brachial artery infusion of acetylcholine (FBFACh), increased ∼30% with trehalose (13.3±1.0 vs. 10.5±1.1 AUC, P=0.02), but not maltose (P=0.40). This improvement in FBFACh was abolished when endothelial nitric oxide (NO) production was inhibited. Endothelium-independent dilation, assessed by FBF to sodium nitroprusside (FBFSNP), also increased ∼30% with trehalose (155±13 vs. 116±12 AUC, P=0.03) but not maltose (P=0.92). Changes in FBFACh and FBFSNP with trehalose were not significant when subjects with Δbody mass≥2.3kg were included. Trehalose supplementation had no effect on conduit artery endothelial function, large elastic artery stiffness or circulating markers of oxidative stress or inflammation (all P>0.1) independent of changes in body weight. Our findings demonstrate that oral trehalose improves resistance artery (microvascular) function, a major risk factor for cardiovascular diseases, in MA/O adults, possibly through increasing NO bioavailability and smooth muscle sensitivity to NO. PMID:27208415

  4. Association of Hypertension With Erectile Function in Chronic Peripheral Arterial Insufficiency Patients

    PubMed Central

    Spessoto, Luis Cesar Fava; Facio, Fernando Nestor; de Arruda, Jose Germano Ferraz; Arruda, Pedro Francisco F.; Gatti, Marcio; Antoniassi, Thiago Silveira; Facio, Maria Fernanda Warick; de Godoy, Jose Maria Pereira

    2016-01-01

    Background Risk factors may influence the improvement or worsening of erectile dysfunction (ED). The aim of the current study was to evaluate the effect of systemic hypertension on ED in patients with peripheral arterial disease. Methods The effect of hypertension on ED was assessed in 125 consecutive patients in a cross-sectional quantitative study. The ages of the patients ranged from 19 to 88 years old (mean: 59.82 ± 10.48 years). The only exclusion criterion was the amputation of one or both legs. The ankle-arm index was assessed and the international index of ED questionnaire was applied to all participants in the study. Results Of the 125 patients, 22 (17.6%) had mild (grade 1), 50 (40.0%) had moderate (grade 2) and 53 (42.4%) had severe (grade 3) ED. Hypertensive patients have more ED, with ED in hypertensive patients being associated to chronic arterial disease. However, in comparison with normotensive patients, hypertension exerts an immediate protective effect on erectile function. Conclusions In conclusion, although erectile function is initially protected by systemic arterial hypertension in patients with chronic arterial disease, both chronic arterial disease and ED deteriorate over the long term in hypertensive patients. PMID:27429678

  5. Embolic stroke after ligation of the pulmonary artery in patients with functional single ventricle.

    PubMed

    Oski, J A; Canter, C E; Spray, T L; Kan, J S; Cameron, D E; Murphy, A M

    1996-10-01

    In the setting of functional single ventricle with pulmonary overcirculation, pulmonary artery banding is frequently used to alleviate symptoms and to prepare for staged repair. At subsequent cavopulmonary anastomosis or Fontan procedure, the pulmonary artery may be ligated at the site of the pulmonary band. This article describes the association of embolic stroke and thrombus in a ligated or divided pulmonary artery stump in three patients with functional single ventricle. These events occurred from 1990 through 1992 among the 1700 inpatient pediatric cardiology admissions at two institutions. The patients, ranging in age from 15 months to 9 years, had cerebral infarctions documented by computed axial tomography scan or magnetic resonance imaging associated with the echocardiographic finding of thrombus in the proximal pulmonary artery stump after the embolic strokes. The strokes occurred 5 days to 5 years after surgery. Two patients had a second infarction within 2 to 5 weeks of the initial stroke. It is concluded that the presence of the ligated pulmonary artery stump may place patients at risk for embolic stroke. Surgical approaches to reduce the risk of thrombus formation should be considered prospectively in this patient group.

  6. Hemodynamics and right-ventricle functional characteristics of a swine carotid artery-jugular vein shunt model of pulmonary arterial hypertension: An 18-month experimental study

    PubMed Central

    Luo, Xiaoju; Huang, Yuanyuan; He, Yun; Li, Zhixian

    2015-01-01

    The continuous changes in pulmonary hemodynamic properties and right ventricular (RV) function in pulmonary arterial hypertension (PAH) have not been fully characterized in large animal model of PAH induced by a carotid artery–jugular vein shunt. A minipig model of PAH was induced by a surgical anastomosis between the left common carotid artery and the left jugular vein. The model was validated by catheter examination and pathologic analyses, and the hemodynamic features and right-ventricle functional characteristics of the model were continuously observed by Doppler echocardiography. Of the 45 minipigs who received the surgery, 27 survived and were validated as models of PAH, reflected by mean pulmonary artery pressure ≥25 mmHg, and typical pathologic changes of pulmonary arterial remodeling and RV fibrosis. Non-invasive indices of pulmonary hemodynamics (pulmonary artery accelerating time and its ratio to RV ventricular ejection time) were temporarily increased, then reduced later, similar to changes in tricuspid annular displacement. The Tei index of the RV was elevated, indicating a progressive impairment in RV function. Surgical anastomosis between carotid artery and jugular vein in a minipig is effective to establish PAH, and non-invasive hemodynamic and right-ventricle functional indices measured by Doppler echocardiography may be used as early indicators of PAH. PMID:25595189

  7. Correlation of CT cerebral vascular territories with function. 3. Middle cerebral artery

    SciTech Connect

    Berman, S.A.; Hayman, L.A.; Hinck, V.C.

    1984-05-01

    Schematic displays are presented of the cerebral territories supplied by branches of the middle cerebral artery as they would appear on axial and coronal computed tomographic (CT) scan sections. Companion diagrams of regional cortical function and a discussion of the fiber tracts are provided to simplify correlation of clinical deficits with coronal and axial CT abnormalities.

  8. Spontanous periodic breathing is associated with sympathetic hyperreactivity and baroreceptor dysfunction in hypertension.

    PubMed

    Binggeli, Christian; Sudano, Isabella; Corti, Roberto; Spieker, Lukas; Jenni, Rolf; Lüscher, Thomas F; Noll, Georg

    2010-05-01

    Intermittent periods of hypoxemia such as during periodic breathing are associated with hypertension and increased sympathetic activity. In patients with sleep apnea syndrome, hypertension is common. Treating apnea improves hypertension and reduces sympathetic outflow. The aim of the present study was to investigate the phenomenon and mechanisms of spontaneous periodic breathing in patients with hypertension. We examined 43 hypertensive patients with untreated hypertension without left-ventricular dysfunction, heart failure or sleep apnea syndrome. Muscle sympathetic nerve activity (MSA), heart rate (HR), blood pressure (BP) and respiration were continuously recorded at rest and during cold-pressor testing. Oxygen and a CO2-enriched gas were used to test central and peripheral chemoreceptors, respectively. Baroreceptor gain was measured using the alpha method. Seven out of 43 patients showed spontaneous periodic breathing while awake. No difference in MSA, HR and BP was seen between patients with and without periodic breathing at rest except the breathing pattern. However, the cold-pressor test caused a larger increase of MSA in patients with periodic breathing (203 +/- 62 vs. 62 +/- 8%, P < 0.0001 by ANOVA), as well as systolic (46 +/- 6 vs. 25 +/- 3 mmHg, P = 0.002) and diastolic BP (26 +/- 5 vs. 12 +/- 1 mmHg, P = 0.004, ANOVA). Baroreceptor gain was markedly higher in patients with periodic breathing. Chemoreceptor sensitivity was comparable. Spontaneous periodic breathing is relatively common in patients with hypertension and is associated with greatly enhanced responses to cold-pressor testing. We suggest increased baroreceptor gain and sympathetic outflow as a cause for the oscillatory respiration pattern via barorespiratory coupling.

  9. Effect of age on left ventricular function during exercise in patients with coronary artery disease

    SciTech Connect

    Hakki, A.H.; DePace, N.L.; Iskandrian, A.S.

    1983-10-01

    The purpose of this study was to assess the effect of age on left ventricular performance during exercise in 79 patients with coronary artery disease (greater than or equal to 50% narrowing of one or more major coronary arteries). Fifty patients under the age of 60 years (group I) and 29 patients 60 years or older (group II) were studied. Radionuclide angiograms were obtained at rest and during symptom-limited upright bicycle exercise. The history of hypertension, angina or Q wave myocardial infarction was similar in both groups. Multivessel coronary artery disease was present in 30 patients (60%) in group I and in 19 patients (66%) in group II (p . not significant). There were no significant differences between the two groups in the hemodynamic variables (at rest or during exercise) of left ventricular ejection fraction, end-diastolic volume, end-systolic volume and cardiac index. Exercise tolerance was higher in group I than in group II (7.8 +/- 0.4 versus 5.7 +/- 0.4 minutes, p . 0.009), although the exercise heart rate and rate-pressure product were not significantly different between the groups. There was poor correlation between age and ejection fraction, end-diastolic volume and end-systolic volume at rest and during exercise. Abnormal left ventricular function at rest or an abnormal response to exercise was noted in 42 patients (84%) in group I and in 25 patients (86%) in group II (p . not significant). Thus, in patients with coronary artery disease, age does not influence left ventricular function at rest or response to exercise. Older patients with coronary artery disease show changes in left ventricular function similar to those in younger patients with corresponding severity of coronary artery disease.

  10. Effect of age on left ventricular function during exercise in patients with coronary artery disease.

    PubMed

    Hakki, A H; DePace, N L; Iskandrian, A S

    1983-10-01

    The purpose of this study was to assess the effect of age on left ventricular performance during exercise in 79 patients with coronary artery disease (greater than or equal to 50% narrowing of one or more major coronary arteries). Fifty patients under the age of 60 years (group I) and 29 patients 60 years or older (group II) were studied. Radionuclide angiograms were obtained at rest and during symptom-limited upright bicycle exercise. The history of hypertension, angina or Q wave myocardial infarction was similar in both groups. Multivessel coronary artery disease was present in 30 patients (60%) in group I and in 19 patients (66%) in group II (p = not significant). There were no significant differences between the two groups in the hemodynamic variables (at rest or during exercise) of left ventricular ejection fraction, end-diastolic volume, end-systolic volume and cardiac index. Exercise tolerance was higher in group I than in group II (7.8 +/- 0.4 versus 5.7 +/- 0.4 minutes, p = 0.009), although the exercise heart rate and rate-pressure product were not significantly different between the groups. There was poor correlation between age and ejection fraction, end-diastolic volume and end-systolic volume at rest and during exercise. Abnormal left ventricular function at rest or an abnormal response to exercise was noted in 42 patients (84%) in group I and in 25 patients (86%) in group II (p = not significant). Thus, in patients with coronary artery disease, age does not influence left ventricular function at rest or response to exercise. Older patients with coronary artery disease show changes in left ventricular function similar to those in younger patients with corresponding severity of coronary artery disease.

  11. Effects of CYP2C19 Polymorphism on Endothelial Function, Arterial Stiffness and Inflammation in Coronary Artery Disease Patients Under Clopidogrel Treatment.

    PubMed

    Siasos, Gerasimos; Zaromitidou, Marina; Oikonomou, Evangelos; Mourouzis, Konstantinos; Tsalamandris, Sotiris; Kioufis, Stamatios; Kokkou, Eleni; Vavuranakis, Manolis; Zografos, Theodoros; Antonopoulos, Alexis; Dimitropoulos, Stathis; Stefanadis, Christodoulos; Papavassiliou, Athanasios G; Tousoulis, Dimitris

    2015-01-01

    Clopidogrel's ability to inhibit platelet function determined its clinical usefulness. The role of CYP2C19*2 genotype on antiplatelet treatment is recently under question. Arterial wall properties and inflammation are key players in atherosclerosis development. Hence, we evaluated the impact of CYP2C19*2 genetic polymorphism on endothelial function, arterial stiffness and inflammation in coronary artery disease (CAD) patients receiving clopidogrel treatment. In this study we enrolled 408 consecutive patients with stable CAD under dual antiplatelet therapy (clopidogrel 75mg/day, aspirin 100mg/day), 30 days after percutaneous coronary intervention. Measurement of flow-mediated dilation (FMD) of the brachial artery was used to evaluate endothelial function. Carotid-femoral pulse wave velocity (PWV) and augmentation index (AIx) was measured to estimate arterial stiffness. Real time polymerase chain reaction was used for the genotyping of CYP2C19*2. Levels of tumor necrosis factor alpha (TNF-a) and interleukin 6 (IL-6) were measured with ELISA. We found no difference in basic clinical and demographic characteristics nor in FMD, PWV, AIx and inflammatory status (p=NS for all) between CYP2C19 homozygotes for the wild type; carriers of reduced function allele and homozygotes for the reduced function allele. CYP2C19*2 loss of action polymorphism causes no impact on vascular function and inflammatory status in stable CAD patients receiving clopidogrel treatment.

  12. Effect of electron radiation on vasomotor function of the left anterior descending coronary artery

    NASA Astrophysics Data System (ADS)

    Sanzari, Jenine K.; Billings, Paul C.; Wilson, Jolaine M.; Diffenderfer, Eric S.; Arce-Esquivel, Arturo A.; Thorne, Pamela K.; Laughlin, Maurice H.; Kennedy, Ann R.

    2015-01-01

    The left anterior descending (LAD, interventricular) coronary artery provides the blood supply to the mid-region of the heart and is a major site of vessel stenosis. Changes in LAD function can have major effects on heart function. In this report, we examined the effect of electron simulated solar particle event (eSPE) radiation on LAD function in a porcine animal model. Vasodilatory responses to adenosine diphosphate (ADP; 10-9-10-4 M), bradykinin (BK; 10-11-10-6 M), and sodium nitroprusside (SNP; 10-10-10-4 M) were assessed. The LAD arteries from Control (non-irradiated) and the eSPE (irradiated) animals were isolated and exhibited a similar relaxation response following treatment with either ADP or SNP. In contrast, a significantly reduced relaxation response to BK treatment was observed in the eSPE irradiated group, compared to the control group. These data demonstrate that simulated SPE radiation exposure alters LAD function.

  13. Modification of sympathetic neuronal function in the rat tail artery by dietary lipid treatment

    SciTech Connect

    Panek, R.L.; Dixon, W.R.; Rutledge, C.O.

    1985-06-01

    The effect of dietary lipid treatment on sympathetic neuronal function was examined in isolated perfused tail arteries of adult rats. The hypothesis that dietary manipulations alter the lipid environment of receptor proteins which may result in the perturbation of specific membrane-associated processes that regulate peripheral adrenergic neurotransmission in the vasculature was the basis for this investigation. In the present study, rats were fed semisynthetic diets enriched in either 16% coconut oil (saturated fat) or 16% sunflower oil (unsaturated fat). The field stimulation-evoked release of endogenous norepinephrine and total /sup 3/H was decreased significantly in rats receiving the coconut oil diet when compared to either sunflower oil- or standard lab chow-fed rats. Norepinephrine content in artery segments from coconut oil-treated rats was significantly higher compared to either sunflower oil- or standard lab chow-fed rats. Tail arteries from rats receiving the coconut oil diet displayed significantly lower perfusion pressure responses to nerve stimulation at all frequencies tested when compared to the sunflower oil- or standard lab chow-fed rats. Vasoconstrictor responses of perfused tail arteries exposed to exogenous norepinephrine resulted in an EC50 for norepinephrine that was not changed by the dietary treatment, but adult rats receiving the sunflower oil diet displayed a significantly greater maximum response to exogenous norepinephrine (10(-5) M) compared to arteries from either coconut oil- or standard lab chow-fed rats.

  14. Transfer Function Analysis of the Longitudinal Motion of the Common Carotid Artery Wall

    PubMed Central

    Yli-Ollila, Heikki; Tarvainen, Mika P.; Laitinen, Tomi P.; Laitinen, Tiina M.

    2016-01-01

    The longitudinal motion of the carotid wall is a potential new measure of arterial stiffness. Despite the over decade long research on the subject, the driving force and the specific longitudinal kinetics of the carotid wall has remained unclear. In this study, a transfer function analysis with 20 healthy subjects is presented to derive how the energy from the blood pressure moves the innermost arterial wall longitudinally and how the kinetic energy is then transferred to the outermost arterial layer. The power spectrums display that the main kinetic energy of the longitudinal motion is on band 0–3 Hz with a peak on the 1.1 Hz frequency. There is a large variation among the individuals, how the energy from the blood pressure transfers into the longitudinal motion of the arterial wall since the main direction of the longitudinal motion varies individually and because early arterial stiffening potentially has an effect on the time characteristics of the energy transfer. The energy transfer from the innermost to the outermost wall layer is more straightforward: on average, a 17% of the longitudinal amplitude is lost and an 18.9 ms delay is visible on the 1.0 Hz frequency. PMID:28082917

  15. Percutaneous renal artery embolisation of non-functioning allograft. Preliminary experience.

    PubMed

    Larini, Pietro; Marcato, Carla; Monaco, Delio; Bresciani, Paolo; Capocasale, Enzo; Mazzoni, Maria Patrizia; Dalla Valle, Raffaele; Busi, Nicola

    2005-01-01

    Percutaneous renal artery embolisation has been introduced as an alternative to nephrectomy in patients with non-functioning allograft and Graft Intolerance Syndrome (GIS). The symptoms resulting from GIS include fever, local pain, hypertension and haematuria. From April to October 2003, five patients were treated using this technique. The intraparenchymal renal arteries were embolized by injection of calibrated tris-acryl gelatin microspheres of increasing size (from 100-300 to 700-900 microns) and occlusion was completed by the insertion of 5mm to 8mm steel coils into the renal artery. The procedure was well tolerated in all cases and no major complications occurred. In 3 patients GIS-related symptoms disappeared immediately. One patient required a second embolisation due to collateral circulation arising from a lumbar artery with resolution of symptoms. In the last case, the patient underwent nephrectomy because of septic fever. On the basis of our preliminary experience we believe that, in selected patients, percutaneous renal artery embolisation is an effective, repeatable and minimally invasive alternative to nephrectomy with no significant serious complications.

  16. Analysis of pulsatile blood flow in constricted bifurcated arteries with vorticity-stream function approach.

    PubMed

    Chakravarty, S; Sen, S

    2008-01-01

    This theoretical investigation deals with an analysis of pulsatile blood flow in a model bifurcated artery having a stenosis in the parent arterial lumen. The geometry of the bifurcated arterial segment with an implanted stenosis in the parent duct is given an appropriate mathematical shape with the introduction of suitable curvature at the lateral junction and the flow divider. The vascular wall deformability is duly accounted for although the development of atherosclerosis in the arteries reduces its elastic property to some extent. The streaming blood contained in the bifurcated artery is treated to be Newtonian. The flow dynamic analysis applies two-dimensional unsteady incompressible nonlinear Navier-Stokes equations rewritten in the vorticity-stream function formulation. Following a radial coordinate transformation, these equations are solved numerically by a finite difference scheme with the approximate choice of the inlet and boundary conditions in concert with the biophysical point of view. The final numerical results are highlighted at the end of the paper through the exhibition of the wall shear stress and several time-variant patterns of streamlines and vorticity contours of the flow phenomena, which are highly influenced by the severity of the stenosis and the angle of bifurcation. The applicability of the present model is thus established.

  17. Functional and structural changes in internal pudendal arteries underlie erectile dysfunction induced by androgen deprivation

    PubMed Central

    Alves-Lopes, Rhéure; Neves, Karla B; Silva, Marcondes AB; Olivon, Vânia C; Ruginsk, Silvia G; Antunes-Rodrigues, José; Ramalho, Leandra NZ; Tostes, Rita C; Carneiro, Fernando Silva

    2017-01-01

    Androgen deficiency is strongly associated with erectile dysfunction (ED). Inadequate penile arterial blood flow is one of the major causes of ED. The blood flow to the corpus cavernosum is mainly derived from the internal pudendal arteries (IPAs); however, no study has evaluated the effects of androgen deprivation on IPA's function. We hypothesized that castration impairs IPAs reactivity and structure, contributing to ED. In our study, Wistar male rats, 8-week-old, were castrated and studied 30 days after orchiectomy. Functional and structural properties of rat IPAs were determined using wire and pressure myograph systems, respectively. Protein expression was determined by Western blot and immunohistochemistry. Plasma testosterone levels were determined using the IMMULITE 1000 Immunoassay System. Castrated rats exhibited impaired erectile function, represented by decreased intracavernosal pressure/mean arterial pressure ratio. IPAs from castrated rats exhibited decreased phenylephrine- and electrical field stimulation (EFS)-induced contraction and decreased acetylcholine- and EFS-induced vasodilatation. IPAs from castrated rats exhibited decreased internal diameter, external diameter, thickness of the arterial wall, and cross-sectional area. Castration decreased nNOS and α-actin expression and increased collagen expression, p38 (Thr180/Tyr182) phosphorylation, as well as caspase 3 cleavage. In conclusion, androgen deficiency is associated with impairment of IPA reactivity and structure and increased apoptosis signaling markers. Our findings suggest that androgen deficiency-induced vascular dysfunction is an event involving hypotrophic vascular remodeling of IPAs. PMID:27391248

  18. Loss of Elastic Fiber Integrity Compromises Common Carotid Artery Function: Implications for Vascular Aging.

    PubMed

    Ferruzzi, J; Bersi, M R; Mecham, R P; Ramirez, F; Yanagisawa, H; Tellides, G; Humphrey, J D

    2016-06-01

    Competent elastic fibers endow central arteries with the compliance and resilience that are fundamental to their primary mechanical function in vertebrates. That is, by enabling elastic energy to be stored in the arterial wall during systole and then to be used to work on the blood during diastole, elastic fibers decrease ventricular workload and augment blood flow in pulsatile systems. Indeed, because elastic fibers are formed during development and stretched during somatic growth, their continual tendency to recoil contributes to the undulation of the stiffer collagen fibers, which facilitates further the overall compliance of the wall under physiologic pressures while allowing the collagen to limit over-distension during acute increases in blood pressure. In this paper, we use consistent methods of measurement and quantification to compare the biaxial material stiffness, structural stiffness, and energy storage capacity of murine common carotid arteries having graded degrees of elastic fiber integrity - normal, elastin-deficient, fibrillin-1 deficient, fibulin-5 null, and elastase-treated. The finding that the intrinsic material stiffness tends to be maintained nearly constant suggests that intramural cells seek to maintain a favorable micromechanical environment in which to function. Nevertheless, a loss of elastic energy storage capability due to the loss of elastic fiber integrity severely compromises the primary function of these central arteries.

  19. Functional up-regulation of KCNA gene family expression in murine mesenteric resistance artery smooth muscle

    PubMed Central

    Fountain, S J; Cheong, A; Flemming, R; Mair, L; Sivaprasadarao, A; Beech, D J

    2004-01-01

    This study focused on the hypothesis that KCNA genes (which encode KVα1 voltage-gated K+ channels) have enhanced functional expression in smooth muscle cells of a primary determinant of peripheral resistance – the small mesenteric artery. Real-time PCR methodology was developed to measure cell type-specific in situ gene expression. Profiles were determined for arterial myocyte expression of RNA species encoding KVα1 subunits as well as KVβ1, KVα2.1, KVγ9.3, BKCaα1 and BKCaβ1. The seven major KCNA genes were expressed and more readily detected in endothelium-denuded mesenteric resistance artery compared with thoracic aorta; quantification revealed dramatic differential expression of one to two orders of magnitude. There was also four times more RNA encoding KVα2.1 but less or similar amounts encoding KVβ1, KVγ9.3, BKCaα1 and BKCaβ1. Patch-clamp recordings from freshly isolated smooth muscle cells revealed dominant KVα1 K+ current and current density twice as large in mesenteric cells. Therefore, we suggest the increased RNA production of the resistance artery impacts on physiological function, although there is quantitatively less K+ current than might be expected. The mechanism conferring up-regulated expression of KCNA genes may be common to all the gene family and play a functional role in the physiological control of blood pressure. PMID:14742730

  20. Androgenic anabolic steroids and arterial structure and function in male bodybuilders.

    PubMed

    Sader, M A; Griffiths, K A; McCredie, R J; Handelsman, D J; Celermajer, D S

    2001-01-01

    The study examined arterial and cardiac structure and function in bodybuilders using androgenic anabolic steroids (AAS), compared to non-steroid-using bodybuilder controls. Adverse cardiovascular events have been reported in bodybuilders taking anabolic steroids. The cardiovascular effects of AAS, however, have not been investigated in detail. We recruited 20 male bodybuilders (aged 35 +/- 3 years), 10 actively using AAS and 10 who denied ever using steroids. Serum lipid and hormone levels, carotid intima-media thickness (IMT), arterial reactivity, and left ventricular (LV) dimensions were measured. Vessel diameter was measured by ultrasound at rest, during reactive hyperemia (an endothelium-dependent response, leading to flow-mediated dilation, FMD), and after sublingual nitroglycerin (GTN, an endothelium-independent dilator). Arterial reactivity was also measured in 10 age-matched non-bodybuilding sedentary controls. Use of AAS was associated with significant decreases in high density lipoprotein cholesterol, sex hormone binding globulin, testosterone and gonadotrophin levels, and significant increases in LV mass and self-reported physical strength (p < 0.05). Carotid IMT (0.60 +/- 0.04 mm vs. 0.63 +/- 0.07 mm), arterial FMD (4.7 +/- 1.4% vs. 4.1 +/- 0.7%) and GTN responses (11.0 +/- 1.9% vs. 14.4 +/- 1.7%) were similar in both bodybuilding groups (p > 0.2). The GTN responses were significantly lower and carotid IMT significantly higher in both bodybuilding groups, however, compared with the non-bodybuilding sedentary controls (p = 0.01). Although high-level bodybuilding is associated with impaired vascular reactivity and increased arterial thickening, the use of AAS per se is not associated with significant abnormalities of arterial structure or function.

  1. Renal function after off-pump versus on-pump coronary artery bypass grafting.

    PubMed

    Singh, Rana Sandip; Thingnam, Shyam Kumar Singh; Mishra, Anand Kumar; Verma, Indu; Kumar, Vikas

    2017-01-01

    Background Renal dysfunction is a well-recognized major complication after coronary artery bypass grafting. Off-pump coronary artery bypass theoretically appears to have less impact on renal function. We estimated preoperative and postoperative creatinine clearance as a marker of renal dysfunction in patients undergoing off-pump and on-pump coronary artery bypass. Methods Thirty patients undergoing coronary artery bypass were randomly allocated to undergo either on-pump ( n = 15) or off-pump surgery ( n = 15). The two groups had similar preoperative demographic characteristics. Serum creatinine and creatinine clearance were measured for 4 days postoperatively and the results were compared with preoperative levels. Results The rise in serum creatinine on postoperative day 1 was 0.28 mgċdL(-1) in the on-pump group and 0.22 mgċdL(-1) in the off-pump group ( p = 0.27); on postoperative day 4 it was 0.15 mgċdL(-1) and 0.10 mgċdL(-1), respectively, ( p = 0.28). Similarly, the fall in creatinine clearance was 17.34 mLċmin(-1) in the on-pump group and 19.62 mLċmin(-1) in the off-pump group on postoperative day 1 ( p = 0.42), and 10.9 and 10.94 mLċmin(-1), respectively, on postoperative day 4 ( p = 0.64). Conclusion Renal function is not affected by the technique of coronary artery bypass surgery, whether with or without cardiopulmonary bypass, in spite of the theoretical advantage of off-pump surgery. Our study suggests that off-pump coronary artery bypass surgery does not confer significant protection from postoperative renal dysfunction in low-risk patients, when compared with on-pump surgery.

  2. [Involvement of cross interaction between central cholinergic and histaminergic systems in the nucleus tractus solitarius in regulating carotid sinus baroreceptor reflex].

    PubMed

    Hu, Li-Xun; Zhang, Guo-Xing; Zhang, Yu-Ying; Zhao, Hong-Fen; Yu, Kang-Ying; Wang, Guo-Qing

    2013-12-25

    The carotid sinus baroreceptor reflex (CSR) is an important approach for regulating arterial blood pressure homeostasis instantaneously and physiologically. Activation of the central histaminergic or cholinergic systems results in CSR functional inhibitory resetting. However, it is unclear whether two systems at the nucleus tractus solitarius (NTS) level display cross interaction to regulate the CSR or not. In the present study, the left or right carotid sinus region was isolated from the systemic circulation in Sprague-Dawley rats (sinus nerve was reserved) anesthetized with pentobarbital sodium. Respective intubation was conducted into one side isolated carotid sinus and into the femoral artery for recording the intracarotid sinus pressure (ISP) and mean arterial pressure (MAP) simultaneously with pressure transducers connection in vivo. ISP was set at the level of 0 mmHg to eliminate the effect of initial internal pressure of the carotid sinus on the CSR function. To trigger CSR, the ISP was quickly elevated from 0 mmHg to 280 mmHg in a stepwise manner (40 mmHg) which was added at every step for over 4 s, and then ISP returned to 0 mmHg in similar steps. The original data of ISP and corresponding MAP were fitted to a modified logistic equation with five parameters to obtain the ISP-MAP, ISP-Gain relationship curves and the CSR characteristic parameters, which were statistically compared and analyzed separately. Under the precondition of no influence on the basic levels of the artery blood pressure, the effects and potential regulatory mechanism of preceding microinjection with different cholinoceptor antagonists, the selective cholinergic M1 receptor antagonist, i.e., pirenzepine (PRZ), the M2 receptor antagonist, i.e., methoctramine (MTR) or the N1 receptor antagonist, i.e., hexamethonium (HEX) into the NTS on the changes in function of CSR induced by intracerebroventricular injection (i.c.v.) of histamine (HA) in rats were observed. Meanwhile, the actions and

  3. Automated Determination of Arterial Input Function for Dynamic Susceptibility Contrast MRI from Regions around Arteries Using Independent Component Analysis

    PubMed Central

    Lai, Jui-Jen; Chang, Chin-Ching

    2016-01-01

    Purpose. Quantitative cerebral blood flow (CBF) measurement using dynamic susceptibility contrast- (DSC-) MRI requires accurate estimation of the arterial input function (AIF). The present work utilized the independent component analysis (ICA) method to determine the AIF in the regions adjacent to the middle cerebral artery (MCA) by the alleviated confounding of partial volume effect. Materials and Methods. A series of spin-echo EPI MR scans were performed in 10 normal subjects. All subjects received 0.2 mmol/kg Gd-DTPA contrast agent. AIFs were calculated by two methods: (1) the region of interest (ROI) selected manually and (2) weighted average of each component selected by ICA (weighted-ICA). The singular value decomposition (SVD) method was then employed to deconvolve the AIF from the tissue concentration time curve to obtain quantitative CBF values. Results. The CBF values calculated by the weighted-ICA method were 41.1 ± 4.9 and 22.1 ± 2.3 mL/100 g/min for cortical gray matter (GM) and deep white matter (WM) regions, respectively. The CBF values obtained based on the manual ROIs were 53.6 ± 12.0 and 27.9 ± 5.9 mL/100 g/min for the same two regions, respectively. Conclusion. The weighted-ICA method allowed semiautomatic and straightforward extraction of the ROI adjacent to MCA. Through eliminating the partial volume effect to minimum, the CBF thus determined may reflect more accurate physical characteristics of the T2⁎ signal changes induced by the contrast agent. PMID:27547451

  4. Systemic leukotriene B4 receptor antagonism lowers arterial blood pressure and improves autonomic function in the spontaneously hypertensive rat.

    PubMed

    Marvar, Paul J; Hendy, Emma B; Cruise, Thomas D; Walas, Dawid; DeCicco, Danielle; Vadigepalli, Rajanikanth; Schwaber, James S; Waki, Hidefumi; Murphy, David; Paton, Julian F R

    2016-10-15

    Evidence indicates an association between hypertension and chronic systemic inflammation in both human hypertension and experimental animal models. Previous studies in the spontaneously hypertensive rat (SHR) support a role for leukotriene B4 (LTB4 ), a potent chemoattractant involved in the inflammatory response, but its mode of action is poorly understood. In the SHR, we observed an increase in T cells and macrophages in the brainstem; in addition, gene expression profiling data showed that LTB4 production, degradation and downstream signalling in the brainstem of the SHR are dynamically regulated during hypertension. When LTB4 receptor 1 (BLT1) receptors were blocked with CP-105,696, arterial pressure was reduced in the SHR compared to the normotensive control and this reduction was associated with a significant decrease in systolic blood pressure (BP) indicators. These data provide new evidence for the role of LTB4 as an important neuro-immune pathway in the development of hypertension and therefore may serve as a novel therapeutic target for the treatment of neurogenic hypertension. Accumulating evidence indicates an association between hypertension and chronic systemic inflammation in both human hypertension and experimental animal models. Previous studies in the spontaneously hypertensive rat (SHR) support a role for leukotriene B4 (LTB4 ), a potent chemoattractant involved in the inflammatory response. However, the mechanism for LTB4 -mediated inflammation in hypertension is poorly understood. Here we report in the SHR, increased brainstem infiltration of T cells and macrophages plus gene expression profiling data showing that LTB4 production, degradation and downstream signalling in the brainstem of the SHR are dynamically regulated during hypertension. Chronic blockade of the LTB4 receptor 1 (BLT1) receptor with CP-105,696, reduced arterial pressure in the SHR compared to the normotensive control and this reduction was associated with a significant

  5. Assessments of endothelial function and arterial stiffness are reproducible in patients with COPD

    PubMed Central

    Rodriguez-Miguelez, Paula; Seigler, Nichole; Bass, Leon; Dillard, Thomas A; Harris, Ryan A

    2015-01-01

    Background Elevated cardiovascular disease risk is observed in patients with COPD. Non-invasive assessments of endothelial dysfunction and arterial stiffness have recently emerged to provide mechanistic insight into cardiovascular disease risk in COPD; however, the reproducibility of endothelial function and arterial stiffness has yet to be investigated in this patient population. Objectives This study sought to examine the within-day and between-day reproducibility of endothelial function and arterial stiffness in patients with COPD. Methods Baseline diameter, peak diameter, flow-mediated dilation, augmentation index, augmentation index at 75 beats per minute, and pulse wave velocity were assessed three times in 17 patients with COPD (six males, eleven females, age range 47–75 years old; forced expiratory volume in 1 second =51.5% predicted). Session A and B were separated by 3 hours (within-day), whereas session C was conducted at least 7 days following session B (between-day). Reproducibility was assessed by: 1) paired t-tests, 2) coefficients of variation, 3) coefficients of variation prime, 4) intra-class correlation coefficient, 5) Pearson’s correlations (r), and 6) Bland–Altman plots. Five acceptable assessments were required to confirm reproducibility. Results Six out of six within-day criteria were met for endothelial function and arterial stiffness outcomes. Six out of six between-day criteria were met for baseline and peak diameter, augmentation index and pulse wave velocity, whereas five out of six criteria were met for flow-mediated dilation. Conclusion The present study provides evidence for within-day and between-day reproducibility of endothelial function and arterial stiffness in patients with COPD. PMID:26396509

  6. Reprint of "Baroreflex function in anurans from different environments".

    PubMed

    Hedrick, Michael S; McNew, Kadi A; Crossley, Dane A

    2015-08-01

    Anurans from terrestrial environments have an enhanced ability to maintain mean arterial blood pressure (Pm) through lymph mobilization in response to desiccation or hemorrhage compared with semiaquatic or aquatic species. Because short term blood pressure homeostasis is regulated by arterial baroreceptors, we compared baroreflex function in three species of anurans that span a range of environments, dehydration tolerance and an ability to maintain Pm with dehydration and hemorrhage. The cardiac limb of the baroreflex loop was studied using pharmacological manipulation of Pm with phenylephrine and sodium nitroprusside (20-200μgkg(-1)), and the resulting changes in heart rate (fH) were quantitatively analyzed using a four-parameter sigmoidal logistic function. Resting Pm in the aquatic species, Xenopus laevis, was 3.6±0.3kPa and was significantly less (P<0.005) than for the semiaquatic species, Lithobates catesbeianus (4.1±0.2kPa), or the terrestrial species, Rhinella marina (4.7±0.2kPa). The maximal baroreflex gain was not different among the three species and ranged from 12.1 to 14.3beatsmin(-1)kPa(-1) and occurred at Pm ranging from 3.0 to 3.8kPa, which were slightly below the resting Pm for each species. Mean arterial blood pressures at rest in the three species were near the saturation point of the baroreflex curve which provides the animals with a greater fH response range to hypotensive, rather than hypertensive, changes in Pm. This is consistent with the hypothesis that arterial baroreceptors are key sensory components that allow anurans to maintain Pm possibly by mobilization of lymphatic return in response to hypotension.

  7. Neural control of circulation and exercise: a translational approach disclosing interactions between central command, arterial baroreflex, and muscle metaboreflex

    PubMed Central

    Michelini, Lisete C.; O'Leary, Donal S.; Raven, Peter B.

    2015-01-01

    The last 100 years witnessed a rapid and progressive development of the body of knowledge concerning the neural control of the cardiovascular system in health and disease. The understanding of the complexity and the relevance of the neuroregulatory system continues to evolve and as a result raises new questions. The purpose of this review is to articulate results from studies involving experimental models in animals as well as in humans concerning the interaction between the neural mechanisms mediating the hemodynamic responses during exercise. The review describes the arterial baroreflex, the pivotal mechanism controlling mean arterial blood pressure and its fluctuations along with the two main activation mechanisms to exercise: central command (parallel activation of central somatomotor and autonomic descending pathways) and the muscle metaboreflex, the metabolic component of exercise pressor reflex (feedback from ergoreceptors within contracting skeletal muscles). In addition, the role of the cardiopulmonary baroreceptors in modulating the resetting of arterial baroreflex is identified, and the mechanisms in the central nervous system involved with the resetting of baroreflex function during dynamic exercise are also described. Approaching a very relevant clinical condition, the review also presents the concept that the impaired arterial baroreflex function is an integral component of the metaboreflex-mediated exaggerated sympathetic tone in subjects with heart failure. This increased sympathetic activity has a major role in causing the depressed ventricular function observed during submaximal dynamic exercise in these patients. The potential contribution of a metaboreflex arising from respiratory muscles is also considered. PMID:26024683

  8. Optical imaging of resting-state functional connectivity in a novel arterial stiffness model.

    PubMed

    Guevara, Edgar; Sadekova, Nataliya; Girouard, Hélène; Lesage, Frédéric

    2013-01-01

    This study aims to assess the impact of unilateral increases in carotid stiffness on cortical functional connectivity measures in the resting state. Using a novel animal model of induced arterial stiffness combined with optical intrinsic signals and laser speckle imaging, resting state functional networks derived from hemodynamic signals are investigated for their modulation by isolated changes in stiffness of the right common carotid artery. By means of seed-based analysis, results showed a decreasing trend of homologous correlation in the motor and cingulate cortices. Furthermore, a graph analysis indicated a randomization of the cortex functional networks, suggesting a loss of connectivity, more specifically in the motor cortex lateral to the treated carotid, which however did not translate in differentiated metabolic activity.

  9. Impact of splenic artery ligation after major hepatectomy on liver function, regeneration and viability.

    PubMed

    Carrapita, Jorge; Abrantes, Ana Margarida; Campelos, Sofia; Gonçalves, Ana Cristina; Cardoso, Dulce; Sarmento-Ribeiro, Ana Bela; Rocha, Clara; Santos, Jorge Nunes; Botelho, Maria Filomena; Tralhão, José Guilherme; Farges, Olivier; Barbosa, Jorge Maciel

    2016-10-11

    It was reported that prevention of acute portal overpressure in small-for-size livers by inflow modulation results in a better postoperative outcome. The aim is to investigate the impact of portal blood flow reduction by splenic artery ligation after major hepatectomy in a murine model. Forty-eight rats were subjected to an 85% hepatectomy or 85% hepatectomy and splenic artery ligation. Both groups were evaluated at 24, 48, 72 and 120 post-operative hours: liver function, regeneration and viability. All methods and experiments were carried out in accordance with Coimbra University guidelines. Splenic artery ligation produces viability increase after 24 h, induces a relative decrease in oxidative stress during the first 48 hours, allows antioxidant capacity increment after 24 h, which is reflected in a decrease of half-time normalized liver curve at 48 h and at 72 h and in an increase of mitotic index between 48 h and 72 h. Splenic artery ligation combined with 85% hepatectomy in a murine model, allows portal inflow modulation, promoting an increase in hepatocellular viability and regeneration, without impairing the function, probably by inducing a less marked elevation of oxidative stress at first 48 hours.

  10. Impact of splenic artery ligation after major hepatectomy on liver function, regeneration and viability

    PubMed Central

    Carrapita, Jorge; Abrantes, Ana Margarida; Campelos, Sofia; Gonçalves, Ana Cristina; Cardoso, Dulce; Sarmento-Ribeiro, Ana Bela; Rocha, Clara; Santos, Jorge Nunes; Botelho, Maria Filomena; Tralhão, José Guilherme; Farges, Olivier; Barbosa, Jorge Maciel

    2016-01-01

    It was reported that prevention of acute portal overpressure in small-for-size livers by inflow modulation results in a better postoperative outcome. The aim is to investigate the impact of portal blood flow reduction by splenic artery ligation after major hepatectomy in a murine model. Forty-eight rats were subjected to an 85% hepatectomy or 85% hepatectomy and splenic artery ligation. Both groups were evaluated at 24, 48, 72 and 120 post-operative hours: liver function, regeneration and viability. All methods and experiments were carried out in accordance with Coimbra University guidelines. Splenic artery ligation produces viability increase after 24 h, induces a relative decrease in oxidative stress during the first 48 hours, allows antioxidant capacity increment after 24 h, which is reflected in a decrease of half-time normalized liver curve at 48 h and at 72 h and in an increase of mitotic index between 48 h and 72 h. Splenic artery ligation combined with 85% hepatectomy in a murine model, allows portal inflow modulation, promoting an increase in hepatocellular viability and regeneration, without impairing the function, probably by inducing a less marked elevation of oxidative stress at first 48 hours. PMID:27725728

  11. Impaired function of alpha-2 adrenoceptors in smooth muscle of mesenteric arteries from spontaneously hypertensive rats.

    PubMed

    Feres, T; Borges, A C; Silva, E G; Paiva, A C; Paiva, T B

    1998-11-01

    The alpha2-adrenoceptor function in mesenteric arteries of spontaneously hypertensive rats (SHR) was investigated by comparing membrane potential changes in response to adrenergic agonists in preparations from female SHR, Wistar-Kyoto (WKY) and normotensive Wistar rats (NWR). Resting membrane potential was found to be less negative in mesenteric arteries from SHR than in those from NWR and WKY. Apamin induced a decrease in the membrane potential of mesenteric artery rings without endothelium from NWR and WKY, but had no effects in those from SHR. Both UK 14,304 and adrenaline, in the presence of prazosin, induced a hyperpolarization that was significantly lower in de-endothelialized mesenteric rings from SHR than in those from NWR and WKY. In mesenteric rings with endothelium, however, similar hyperpolarization was observed in the three strains. In NWR mesenteric rings with endothelium the hyperpolarization induced by activation of alpha2-adrenoceptors was abolished by apamin, whereas in intact SHR mesenteric rings this hyperpolarization was slightly reduced by apamin and more efficiently reduced by Nomega-nitro-L-arginine. It is concluded that the activity of potassium channels coupled to alpha2-adrenoceptors is altered in the smooth muscle cells of SHR mesenteric arteries, contributing to their less negative membrane potential. On the other hand, the endothelial alpha2-receptors are functioning in mesenteric vessels from SHR and their stimulation induces a hyperpolarization mainly through the release of nitric oxide.

  12. Characterization of 5-HT receptors on human pulmonary artery and vein: functional and binding studies

    PubMed Central

    Cortijo, Julio; Martí-Cabrera, Miguel; Bernabeu, Eva; Domènech, Teresa; Bou, Josep; Fernández, Andrés G; Beleta, Jorge; Palacios, José M; Morcillo, Esteban J

    1997-01-01

    This study aimed to investigate the 5-hydroxytryptamine (5-HT) receptors mediating contraction of ring preparations isolated from human pulmonary arteries and veins. In functional studies, the responses to 5-HT, sumatriptan, ergotamine, serotonin-O-carboxymethyl-glycyl-tyrosinamide (SCMGT), α-methyl 5-HT (α-Me) and 2-methyl 5-HT (2-Me) were studied with WAY100635, GR127935, ritanserin, zacopride and SB204070 as antagonists.All agonists produced concentration-dependent contractions of human pulmonary artery and vein preparations. The order of potency (−log EC50 values) was ergotamine (6.88)>5-HT (6.41)⩾SCMGT (6.20)=sumatriptan (6.19) ⩾α-Me (6.04) in the artery, and ergotamine (7.84)>5-HT (6.96)>sumatriptan (6.60)=α-Me (6.56)>SCMGT (6.09) in the vein. The potency of each agonist, except for SCMGT, was greater in vein than in artery preparations. Contractile responses to 5-HT were similar in intact and endothelium-denuded preparations but responses to sumatriptan were enhanced in artery rings without endothelium.GR127935 (1 nM to 0.5 μM) produced an unsurmountable antagonism of the response to 5-HT, sumatriptan, ergotamine and SCMGT. Ritanserin (1 nM to 1 μM) also reduced the maximum contractile responses to 5-HT, ergotamine and α-Me in artery and vein preparations without affecting those to sumatriptan and SCMGT. In endothelium-denuded preparations, surmountable antagonism of sumatriptan by GR127935 (in the presence of ritanserin) and of α-Me by ritanserin (in the presence of GR127935) allowed for the calculation of the apparent pKB values of GR127935 (9.17±0.11 in artery and 9.11±0.05 in vein) and ritanserin (8.82±0.09 in artery and 8.98±0.12 in vein).WAY100635 (1 nM to 1 μM), zacopride (1 nM to 1 μM), or SB204070 (1 nM) did not significantly alter the concentration-response curves for 5-HT, sumatriptan, ergotamine, SCMGT or 2-Me in human pulmonary artery or vein thus indicating that 5-HT1A, 5-HT3 and 5-HT4 receptors are

  13. Characterization of 5-HT receptors on human pulmonary artery and vein: functional and binding studies.

    PubMed

    Cortijo, J; Martí-Cabrera, M; Bernabeu, E; Domènech, T; Bou, J; Fernández, A G; Beleta, J; Palacios, J M; Morcillo, E J

    1997-12-01

    1. This study aimed to investigate the 5-hydroxytryptamine (5-HT) receptors mediating contraction of ring preparations isolated from human pulmonary arteries and veins. In functional studies, the responses to 5-HT, sumatriptan, ergotamine, serotonin-O-carboxymethyl-glycyl-tyrosinamide (SCMGT), alpha-methyl 5-HT (alpha-Me) and 2-methyl 5-HT (2-Me) were studied with WAY100635, GR127935, ritanserin, zacopride and SB204070 as antagonists. 2. All agonists produced concentration-dependent contractions of human pulmonary artery and vein preparations. The order of potency (-log ECS0 values) was ergotamine (6.88) > 5-HT (6.41) > or = SCMGT (6.20) = sumatriptan (6.19) > or = alpha-Me (6.04) in the artery, and ergotamine (7.84) > 5-HT (6.96) > sumatriptan (6.60) = alpha-Me (6.56) > SCMGT (6.09) in the vein. The potency of each agonist, except for SCMGT, was greater in vein than in artery preparations. Contractile responses to 5-HT were similar in intact and endothelium-denuded preparations but responses to sumatriptan were enhanced in artery rings without endothelium. 3. GR127935 (1 nM to 0.5 microM) produced an unsurmountable antagonism of the response to 5-HT, sumatriptan, ergotamine and SCMGT. Ritanserin (1 nM to 1 microM) also reduced the maximum contractile responses to 5-HT, ergotamine and alpha-Me in artery and vein preparations without affecting those to sumatriptan and SCMGT. In endothelium-denuded preparations, surmountable antagonism of sumatriptan by GR127935 (in the presence of ritanserin) and of alpha-Me by ritanserin (in the presence of GR127935) allowed for the calculation of the apparent pK(B) values of GR127935 (9.17+/-0.11 in artery and 9.11+/-0.05 in vein) and ritanserin (8.82+/-0.09 in artery and 8.98+/-0.12 in vein). 4. WAY100635 (1 nM to 1 microM), zacopride (1 nM to 1 microM), or SB204070 (1 nM) did not significantly alter the concentration-response curves for 5-HT, sumatriptan, ergotamine, SCMGT or 2-Me in human pulmonary artery or vein thus

  14. Relationship between left ventricular diastolic function and arterial stiffness in asymptomatic patients with diabetes mellitus.

    PubMed

    Roos, Cornelis J; Auger, Dominique; Djaberi, Roxana; de Koning, Eelco J; Rabelink, Ton J; Pereira, Alberto M; Bax, Jeroen J; Delgado, Victoria; Jukema, J Wouter; Scholte, Arthur J

    2013-03-01

    Left ventricular (LV) diastolic dysfunction and increased arterial stiffness are common in patients with diabetes mellitus (DM). However, the relation between these two pathophysiological factors remains unclear. The aim of this study was to investigate the relationship between LV diastolic function and arterial stiffness as assessed with applanation tonometry. In 142 asymptomatic patients with DM (mean age 48 years, 75 (53 %) men, 72 (51 %) patients with type 2 DM) LV diastolic function was assessed with echocardiography. Arterial stiffness was evaluated measuring the aortic pulse wave velocity (PWV) whereas wave reflection was assessed measuring central systolic blood pressure (cSBP), central pulse pressure (cPP), and augmentation index (AIx) with applanation tonometry. Mean E/A ratio, E' and E/E' ratio were 1.1 ± 0.3, 8.1 ± 2.3 and 9.2 ± 3.3 cm/s, respectively. Mean PWV, mean cSBP, median cPP and mean AIx were 7.9 ± 2.4 m/s, 122 ± 17 mmHg, 40 [35-51] mmHg and 17.9 ± 12.1 %, respectively. PWV was independently associated with LV diastolic dysfunction grade (β = 0.76, p = 0.03). In contrast, measures of wave reflection, cPP, cSBP and AIx were independently related with E/A ratio, but not with the LV diastolic dysfunction grade. Parameters of arterial stiffness and wave reflection are associated with echocardiographic indices of LV diastolic function in asymptomatic patients with DM. Therapies that prevent progression of arterial stiffness and reduce late-systolic pressure overload may help to reduce the prevalence of LV diastolic dysfunction in this population.

  15. Effects of cigarette smoke on endothelial function of pulmonary arteries in the guinea pig

    PubMed Central

    2009-01-01

    Background Cigarette smoking may contribute to pulmonary hypertension in chronic obstructive pulmonary disease by altering the structure and function of pulmonary vessels at early disease stages. The objectives of this study were to evaluate the effects of long-term exposure to cigarette smoke on endothelial function and smooth muscle-cell proliferation in pulmonary arteries of guinea pigs. Methods 19 male Hartley guinea pigs were exposed to the smoke of 7 cigarettes/day, 5 days/week, for 3 and 6 months. 17 control guinea pigs were sham-exposed for the same periods. Endothelial function was evaluated in rings of pulmonary artery and aorta as the relaxation induced by ADP. The proliferation of smooth muscle cells and their phenotype in small pulmonary vessels were evaluated by immunohistochemical expression of α-actin and desmin. Vessel wall thickness, arteriolar muscularization and emphysema were assessed morphometrically. The expression of endothelial nitric oxide synthase (eNOS) was evaluated by Real Time-PCR. Results Exposure to cigarette smoke reduced endothelium-dependent vasodilatation in pulmonary arteries (ANOVA p < 0.05) but not in the aorta. Endothelial dysfunction was apparent at 3 months of exposure and did not increase further after 6 months of exposure. Smoke-exposed animals showed proliferation of poorly differentiated smooth muscle cells in small vessels (p < 0.05) after 3 months of exposure. Prolonged exposure resulted in full muscularization of small pulmonary vessels (p < 0.05), wall thickening (p < 0.01) and increased contractility of the main pulmonary artery (p < 0.05), and enlargement of the alveolar spaces. Lung expression of eNOS was decreased in animals exposed to cigarette smoke. Conclusion In the guinea pig, exposure to cigarette smoke induces selective endothelial dysfunction in pulmonary arteries, smooth muscle cell proliferation in small pulmonary vessels and reduced lung expression of eNOS. These changes appear after 3 months of

  16. Effects of cigarette smoke on endothelial function of pulmonary arteries in the guinea pig.

    PubMed

    Ferrer, Elisabet; Peinado, Víctor Ivo; Díez, Marta; Carrasco, Josep Lluís; Musri, Melina Mara; Martínez, Anna; Rodríguez-Roisin, Robert; Barberà, Joan Albert

    2009-08-14

    Cigarette smoking may contribute to pulmonary hypertension in chronic obstructive pulmonary disease by altering the structure and function of pulmonary vessels at early disease stages. The objectives of this study were to evaluate the effects of long-term exposure to cigarette smoke on endothelial function and smooth muscle-cell proliferation in pulmonary arteries of guinea pigs. 19 male Hartley guinea pigs were exposed to the smoke of 7 cigarettes/day, 5 days/week, for 3 and 6 months. 17 control guinea pigs were sham-exposed for the same periods. Endothelial function was evaluated in rings of pulmonary artery and aorta as the relaxation induced by ADP. The proliferation of smooth muscle cells and their phenotype in small pulmonary vessels were evaluated by immunohistochemical expression of alpha-actin and desmin. Vessel wall thickness, arteriolar muscularization and emphysema were assessed morphometrically. The expression of endothelial nitric oxide synthase (eNOS) was evaluated by Real Time-PCR. Exposure to cigarette smoke reduced endothelium-dependent vasodilatation in pulmonary arteries (ANOVA p < 0.05) but not in the aorta. Endothelial dysfunction was apparent at 3 months of exposure and did not increase further after 6 months of exposure. Smoke-exposed animals showed proliferation of poorly differentiated smooth muscle cells in small vessels (p < 0.05) after 3 months of exposure. Prolonged exposure resulted in full muscularization of small pulmonary vessels (p < 0.05), wall thickening (p < 0.01) and increased contractility of the main pulmonary artery (p < 0.05), and enlargement of the alveolar spaces. Lung expression of eNOS was decreased in animals exposed to cigarette smoke. In the guinea pig, exposure to cigarette smoke induces selective endothelial dysfunction in pulmonary arteries, smooth muscle cell proliferation in small pulmonary vessels and reduced lung expression of eNOS. These changes appear after 3 months of exposure and precede the development

  17. The biomechanical function of arterial elastin in solutes.

    PubMed

    Zou, Yu; Zhang, Yanhang

    2012-07-01

    Elastin is essential to accommodate physiological deformation and provide elastic support for blood vessels. As a long-lived extracellular matrix protein, elastin can suffer from cumulative effects of exposure to chemical damage, which greatly compromises the mechanical function of elastin. The mechanical properties of elastin are closely related to its microstructure and the external chemical environments. The purpose of this study is to investigate the changes in the macroscopic elastic and viscoelastic properties of isolated porcine aortic elastin under the effects of nonenzymatic mediated in vitro elastin-lipid interactions and glycation. Sodium dodecyl sulfate (SDS) was used for elastin-lipid interaction, while glucose was used for glycation of elastin. Elastin samples were incubated in SDS (20 mM) or glucose (2 M) solutions and were allowed to equilibrate for 48 h at room temperature. Control experiments were performed in 1  ×  Phosphate buffered saline (PBS). Biaxial tensile and stress relaxation experiments were performed to study the mechanical behavior of elastin with solute effects. Experimental results reveal that both the elastic and viscoelastic behaviors of elastin change in different biochemical solvents environments. The tangent stiffness of SDS treated elastin decreases to 63.57 ± 4.7% of the control condition in circumference and to 58.43 ± 2.65% in the longitude. Glucose treated elastin exhibits an increase in stiffness to 145.06 ± 1.48% of the control condition in the longitude but remains similar mechanical response in the circumferential direction. During stress relaxation experiments with a holding period of half an hour, elastin treated with SDS or glucose shows more prominent stress relaxation than the untreated ones.

  18. Associations among cerebral microbleeds, cerebral large-artery diseases and endothelial function.

    PubMed

    Peng, Qing; Huang, Yining; Sun, Wei; Xing, Haiying

    2014-01-01

    Endothelial dysfunction is not only an early stage of atherosclerosis, but also involved in the pathogenesis of cerebral small-vessel diseases. Patients with cerebral microbleeds (CMBs) may have arteriolosclerosis as well as systemic atherosclerosis. However, little is known about the associations among CMBs, atherosclerosis of cerebral large arteries, and endothelial function. Our study aimed to investigate the relationships among them. This was a cross-sectional study. Ninety patients hospitalized in Peking University First Hospital with acute ischemic stroke were enrolled consecutively between November 1, 2007 and January 31, 2008. All subjects underwent transcranial Doppler and carotid color duplex ultrasonography to record the intima-media thickness (IMT) of common carotid artery, carotid plaque, and cerebral artery stenosis. Brain magnetic resonance imaging (MRI) routine sequences and gradient recall-echo T2(*)-weighted imaging were performed to count CMBs with clinical data blindness. Endothelial function was evaluated using flow-mediated dilation (FMD) and nitroglycerin-mediated dilation (NMD) of the brachial artery. FMD and NMD were examined by an experienced vascular sonographer using a high-resolution ultrasound. Thirty cases (33.3%) had CMBs with counts ranging from 1 to 30. Both FMD ((9.9 ± 4.8)% vs. (15. 2 ± 7.4)%, P = 0.001) and NMD ((13.7 ± 6.1)% vs. (19.0 ± 7.4)%, P = 0.001) were significantly decreased in CMB-positive patients than in CMB-negative patients. No significant relationships were demonstrated between CMBs and intracranial and/or extracranial artery stenosis. The frequencies of CMBs in patients with IMT≥1.0 mm, carotid plaque, and extracranial artery stenosis were 37.5%, 39.4%, and 47.6% respectively, with no significant difference, but much higher than in patients with IMT <1.0 mm (5%, P < 0.05). In Logistic regression analysis, impaired FMD (OR = 5.783, 95% CI 1.652-6.718, P = 0.007) and high pulse pressure (OR = 6.228, 95% CI 1

  19. Estimation of Total Baroreflex Gain Using an Equilibrium Diagram Between Sympathetic Nerve Activity and Arterial Pressure

    DTIC Science & Technology

    2007-11-02

    drawback that an isolation technique of the baroreceptor regions is not applicable to clinical settings. Accordingly, baroreflex sensitivity (BRS) of...Abstract- The arterial baroreflex system may be divided into the mechano-neural arc from pressure input to sympathetic nerve activity (SNA) and the...neuro-mechanical arc from SNA to arterial pressure (AP). We explored a new strategy to estimate total baroreflex gain (Gbaro) using an equilibrium

  20. Improved hepatic arterial fraction estimation using cardiac output correction of arterial input functions for liver DCE MRI

    NASA Astrophysics Data System (ADS)

    Chouhan, Manil D.; Bainbridge, Alan; Atkinson, David; Punwani, Shonit; Mookerjee, Rajeshwar P.; Lythgoe, Mark F.; Taylor, Stuart A.

    2017-02-01

    Liver dynamic contrast enhanced (DCE) MRI pharmacokinetic modelling could be useful in the assessment of diffuse liver disease and focal liver lesions, but is compromised by errors in arterial input function (AIF) sampling. In this study, we apply cardiac output correction to arterial input functions (AIFs) for liver DCE MRI and investigate the effect on dual-input single compartment hepatic perfusion parameter estimation and reproducibility. Thirteen healthy volunteers (28.7  ±  1.94 years, seven males) underwent liver DCE MRI and cardiac output measurement using aortic root phase contrast MRI (PCMRI), with reproducibility (n  =  9) measured at 7 d. Cardiac output AIF correction was undertaken by constraining the first pass AIF enhancement curve using the indicator-dilution principle. Hepatic perfusion parameters with and without cardiac output AIF correction were compared and 7 d reproducibility assessed. Differences between cardiac output corrected and uncorrected liver DCE MRI portal venous (PV) perfusion (p  =  0.066), total liver blood flow (TLBF) (p  =  0.101), hepatic arterial (HA) fraction (p  =  0.895), mean transit time (MTT) (p  =  0.646), distribution volume (DV) (p  =  0.890) were not significantly different. Seven day corrected HA fraction reproducibility was improved (mean difference 0.3%, Bland-Altman 95% limits-of-agreement (BA95%LoA)  ±27.9%, coefficient of variation (CoV) 61.4% versus 9.3%, ±35.5%, 81.7% respectively without correction). Seven day uncorrected PV perfusion was also improved (mean difference 9.3 ml min-1/100 g, BA95%LoA  ±506.1 ml min-1/100 g, CoV 64.1% versus 0.9 ml min-1/100 g, ±562.8 ml min-1/100 g, 65.1% respectively with correction) as was uncorrected TLBF (mean difference 43.8 ml min-1/100 g, BA95%LoA  ±586.7 ml min-1/ 100 g, CoV 58.3% versus 13.3 ml min-1/100 g, ±661.5 ml min-1/100 g, 60.9% respectively with correction

  1. Impact of excess body weight on arterial structure, function, and blood pressure in firefighters.

    PubMed

    Fahs, Christopher A; Smith, Denise L; Horn, Gavin P; Agiovlasitis, Stamatis; Rossow, Lindy M; Echols, George; Heffernan, Kevin S; Fernhall, Bo

    2009-11-15

    Cardiovascular disease is the leading cause of death among firefighters. The purpose of the present study was to examine the effect of excess body weight on arterial structure and function and blood pressure (BP) in relatively young, apparently healthy, firefighters. The body mass index, brachial BP, carotid BP, aortic BP, radial augmentation index, central pulse wave velocity, forearm blood flow, forearm vasodilatory capacity, carotid arterial compliance, carotid intima-media thickness, and brachial flow-mediated dilation were assessed in 110 firefighters (aged 29.7 +/- 8.0 years). The group was divided into equal tertiles according to the body mass index (<25.9, 25.9 to 29.4, and >or=29.5 kg/m(2)). Group differences in hemodynamics, anthropometrics, microvascular function, and macrovascular structure and function were tested using multivariate analysis of variance. The obese group was older, heavier, and had a larger waist circumference compared to the lean and overweight groups (p <0.05). The overweight group was also older, heavier, and had a larger waist circumference than the lean group (p <0.05). Compared to the lean group, the overweight and obese groups had a greater systolic BP (p <0.05). The obese group also had a significantly greater mean arterial BP and carotid systolic BP than the lean group (p <0.05). The obese group had greater beta stiffness and elastic modulus compared to the lean and overweight groups (p <0.05), but no group differences were found in endothelial function. In conclusion, in a population of relatively young firefighters, an increased body mass index was associated with elevated peripheral BP and arterial stiffness, with no apparent decrements in endothelial function.

  2. Exercise training and artery function in humans: nonresponse and its relationship to cardiovascular risk factors.

    PubMed

    Green, Daniel J; Eijsvogels, Thijs; Bouts, Yvette M; Maiorana, Andrew J; Naylor, Louise H; Scholten, Ralph R; Spaanderman, Marc E A; Pugh, Christopher J A; Sprung, Victoria S; Schreuder, Tim; Jones, Helen; Cable, Tim; Hopman, Maria T E; Thijssen, Dick H J

    2014-08-15

    The objectives of our study were to examine 1) the proportion of responders and nonresponders to exercise training in terms of vascular function; 2) a priori factors related to exercise training-induced changes in conduit artery function, and 3) the contribution of traditional cardiovascular risk factors to exercise-induced changes in artery function. We pooled data from our laboratories involving 182 subjects who underwent supervised, large-muscle group, endurance-type exercise training interventions with pre-/posttraining measures of flow-mediated dilation (FMD%) to assess artery function. All studies adopted an identical FMD protocol (5-min ischemia, distal cuff inflation), contemporary echo-Doppler methodology, and observer-independent automated analysis. Linear regression analysis was used to identify factors contributing to changes in FMD%. We found that cardiopulmonary fitness improved, and weight, body mass index (BMI), cholesterol, and mean arterial pressure (MAP) decreased after training, while FMD% increased in 76% of subjects (P < 0.001). Training-induced increase in FMD% was predicted by lower body weight (β = -0.212), lower baseline FMD% (β = -0.469), lower training frequency (β = -0.256), and longer training duration (β = 0.367) (combined: P < 0.001, r = 0.63). With the exception of a modest correlation with total cholesterol (r = -0.243, P < 0.01), changes in traditional cardiovascular risk factors were not significantly related to changes in FMD% (P > 0.05). In conclusion, we found that, while some subjects do not demonstrate increases following exercise training, improvement in FMD% is present in those with lower pretraining body weight and endothelial function. Moreover, exercise training-induced change in FMD% did not correlate with changes in traditional cardiovascular risk factors, indicating that some cardioprotective effects of exercise training are independent of improvement in risk factors.

  3. Associations of arterial stiffness and cognitive function with physical fitness in patients with chronic stroke.

    PubMed

    Lee, Yong Hee; Yoon, Eun Sun; Park, Soo Hyun; Heffernan, Kevin S; Lee, Chong; Jae, Sae Young

    2014-05-01

    To determine whether arterial stiffness is associated with cognitive function after adjustment for physical fitness in patients with chronic stroke. Cross-sectional analyses were conducted in 102 patients with chronic stroke who participated in an exercise rehabilitation programme. Carotid femoral pulse wave velocity and augmentation index were measured as indices of arterial stiffness and central systolic loading. Cognitive function was assessed with the Mini Mental State Examination. Parameters of physical fitness included the 6-min walk test, flexibility, balance, and muscle strength tests. Carotid femoral pulse wave velocity was significantly associated with Mini Mental State Examination (r = -0.45, p < 0.01) and parameters of physical fitness (r = -0.45~ -0.55, p  < 0.01, all). Mini Mental State Examination was significantly associated with parameters of physical fitness (r = 0.32~0.46, p < 0.01, all). In multivariable linear regression models, carotid femoral pulse wave velocity was inversely associated with Mini Mental State Examination after adjustment for multiple risk factors (beta = -0.33, p = 0.01). However, the association was attenuated and became non-significant after additional adjustment for physical fitness (beta = -0.11, p = 0.39). Arterial stiffness measured by carotid femoral pulse wave velocity is associated with cognitive function in patients with chronic stroke, but not after adjustment for physical fitness. Maintaining appropriate levels of physical fitness may have a favourable effect on both vascular and cognitive function in patients with stroke.

  4. Botulinum toxin as a treatment for functional popliteal artery entrapment syndrome.

    PubMed

    Isner-Horobeti, Marie-Eve; Muff, Guillaume; Masat, Julien; Daussin, Jean-Luc; Dufour, Stephane P; Lecocq, Jehan

    2015-06-01

    Functional popliteal artery entrapment syndrome is responsible for exercise-induced muscle leg pain. This syndrome is caused, in most of the cases, by the excessive size of the gastrocnemius muscles. Currently, its treatment is based only on surgery with variable results. We report the case of a young professional soldier in a combat unit with bilateral functional popliteal artery entrapment syndrome that was confirmed by dynamic arteriography, magnetic resonance angiography, and ultrasonography and did not improve after bilateral popliteal arteriolysis without resection of the gastrocnemius medial head. Treatment by injecting botulinum toxin in the proximal part of the gastrocnemius muscles was proposed and carried out. Regular follow-up (from 1 month to 3 yr after botulinum toxin treatment) showed the disappearance of exercise-induced pain and the improvement of the patient's physical and sports performance. Results of follow-up ultrasonography during dynamic maneuvers at 2.5 months and 2 yr after botulinum toxin injection were normal. Neither adverse effects nor motor deficit of the gastrocnemius muscles was reported. This case report suggests that botulinum toxin treatment could be an alternative to surgery for patients with functional popliteal artery entrapment syndrome. Botulinum toxin could reduce functional compression and, consequently, exercise-induced pain by decreasing the volume of the gastrocnemius muscle.

  5. Endothelin receptor subtypes and their functional relevance in human small coronary arteries

    PubMed Central

    Pierre, Lisa N; Davenport, Anthony P

    1998-01-01

    The potent constrictor peptide endothelin (ET) has been implicated in various cardiovascular disorders including myocardial infarction and atherosclerosis. We have investigated the nature of ET receptor subtypes present on human small coronary arteries.Small coronary arteries were mounted in a wire-myograph for in vitro pharmacology. To investigate the ET receptor subtypes present in different segments of the coronary vascular tree, arteries were grouped according to internal diameter. Responses in arteries with small internal diameters (mean 316.7±7.9 μm; Group B) were compared to those in larger arteries (mean 586.2±23.1 μm; Group A).ET-1 consistently and potently contracted arteries from Group A and B, with EC50 values of 1.7 (0.9–3.2) nM (n=15) and 2.3 (1.4–4.2) nM (n=14), respectively. No correlation was observed between ET-1 potency and internal diameter. The response to ET-1 was potently antagonized by the selective ETA receptor antagonist PD156707 in both Group A and Group B, yielding pA2 values of 8.60±0.12 (n=4–6) and 8.38±0.17 (n=4–6), respectively. Slopes from Schild regression were not significantly different from unity.In contrast to ET-1, individual responses to ET-3 were variable. While all arteries from Group A responded to ET-3 (EC50∼69 (23–210) nM) (n=12), no response was obtained in 5 of the 14 tested in Group B. Of those responding, many failed to reach a maximum at concentrations up to 1 μM. ET-1 was more potent than ET-3 in all arteries tested. A biphasic ET-3 response was observed in 8 arteries suggesting that a small ETB population was also present in some patients. The selective ETB receptor agonist sarafotoxin S6c had little or no effect up to 10 nM (n=4–6).Responses to ET-1 and ET-3 were unaffected by removal of the endothelium in arteries from both groups suggesting a lack of functional, relaxant ETB receptors on endothelial cells (n=5).Using autoradiography, specific high density binding of the non

  6. Cardiovascular Risk Factors and Disease Characteristics Are Consistently Associated with Arterial Function in Rheumatoid Arthritis.

    PubMed

    Gunter, Sule; Robinson, Chanel; Norton, Gavin R; Woodiwiss, Angela J; Tsang, Linda; Dessein, Patrick H; Millen, Aletta M E

    2017-08-01

    Arterial properties influence cardiovascular disease (CVD) risk. We identified potential determinants of arterial function in patients with rheumatoid arthritis (RA). Relationships of traditional cardiovascular risk factors and RA characteristics with arterial stiffness (pulse wave velocity), wave reflection (augmentation index, reflected wave pressure, and reflection magnitude), and pressure pulsatility (central systolic and pulse pressure, peripheral pulse pressure, pulse pressure amplification, and forward wave pressure) were identified in multivariable backward regression models among 177 patients without established CVD (118 white, 32 Asian, 22 black, 5 mixed ancestry). Recorded characteristics explained 37% (pulse wave velocity) to 71% (reflected wave pressure) of the variability in arterial function. These factors were particularly associated with wave reflection and pressure pulsatility: RA duration (p = 0.04), rheumatoid factor status (p = 0.01 to 0.03), leukocyte counts (p = 0.02 to 0.05), and total cholesterol (p < 0.01 to 0.03). Body mass index (p < 0.01 to 0.02) and insulin resistance (p < 0.01 to 0.01) were related to reduced wave reflection and peripheral pulse pressure. Exercise (p = 0.02) and alcohol consumption (p < 0.01) were associated with increased pulse pressure amplification and decreased peripheral pulse pressure, respectively. Tumor necrosis factor-α inhibition (p < 0.01) was related to reduced pulse wave velocity, and tetracycline use (p = 0.02) to decreased peripheral pulse pressure. Traditional cardiovascular risk factors and disease characteristics are consistently associated with vascular hemodynamic alterations in RA. The relative effect of arterial stiffness, wave reflection, and pressure pulsatility on CVD risk in RA needs further study.

  7. Fenofibrate effects on arterial endothelial function in adults with type 2 diabetes mellitus: A FIELD substudy.

    PubMed

    Harmer, Jason A; Keech, Anthony C; Veillard, Anne-Sophie; Skilton, Michael R; Marwick, Thomas H; Watts, Gerald F; Meredith, Ian T; Celermajer, David S

    2015-09-01

    Dislipidaemia in type 2 diabetes mellitus contributes to arterial endothelial dysfunction and an increased risk of cardiovascular disease. Fenofibrate, a lipid-regulating peroxisome proliferator-activated receptor-α (PPARα) agonist, has been shown to reduce vascular complications in adults with type 2 diabetes. However, the mechanisms for such benefit are not well understood. We examined the effects of fenofibrate on brachial artery endothelial function in adults with type 2 diabetes. In a prospectively designed substudy of the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study, we assessed arterial flow-mediated dilatation (FMD; endothelium-dependent dilatation) and dilator responses to glyceryl trinitrate (GTN, an endothelium-independent dilator) in a subset of 193 representative adults. Traditional risk factors were assessed at baseline, 4 months and 2 years after randomised treatment allocation to fenofibrate (200 mg daily) or placebo. The prespecified primary study endpoint was the difference in FMD between treatment groups at 4 months. Fenofibrate was associated with a significant improvement at 4 months compared with placebo (+1.05% (absolute); P=0.03); GTN-dilator responses were unchanged (P=0.77). After 2 years, FMD was similar in both groups (P=0.46). In multivariable models, none of the fenofibrate-related changes in lipoproteins and lipids were significantly associated with improved FMD on fenofibrate at 4 months. Treatment with fenofibrate significantly improved arterial endothelial function after 4 months. However, the effect was no longer apparent after 2 years. The long-term beneficial vascular effects of fenofibrate in type 2 diabetes are likely to be mediated via mechanisms other than improvement in endothelium-dependent dilatation of conduit arteries, and may differ for the microcirculation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Beta-1-Selective Beta-Blockers and Cognitive Functions in Patients With Coronary Artery Disease: A Cross-Sectional Study.

    PubMed

    Burkauskas, Julius; Noreikaite, Aurelija; Bunevicius, Adomas; Brozaitiene, Julija; Neverauskas, Julius; Mickuviene, Narseta; Bunevicius, Robertas

    2016-01-01

    The association between current beta-1-selective beta-blocker use and cognitive function was evaluated in 722 patients with coronary artery disease without dementia. Beta-1-selective beta-blocker use was associated with worse incidental learning independently of sociodemographic characteristics, clinical coronary artery disease severity, and depression/anxiety.

  9. [Asymmetric function of the pes hippocampi in experimental stress-induced arterial hypertension of albino rats].

    PubMed

    Ljowschina, I P; Hecht, K

    1976-01-01

    Relations between a unilateral lesion of circumscribed structures of the Pes hippocampi on the one hand, and stress-induced blood-pressure and learning behaviour, on the other, were studied. An asymmetric functioning of the CNS was analyzed, in which unilateral exclusion of right-hand hippocampal structures stimulates processes of excitation, while lesion of left-hand structures causes prevalence of inhibitory processes. The resulting impairment of the emotional equilibrium potentiates the stress action's contribution to the development of arterial hypertension.

  10. Ketoprofen combined with artery graft entubulization improves functional recovery of transected peripheral nerves.

    PubMed

    Mohammadi, Rahim; Mehrtash, Moein; Nikonam, Nima; Mehrtash, Moied; Amini, Keyvan

    2014-12-01

    The objective was to assess the local effect of ketoprofen on sciatic nerve regeneration and functional recovery. Eighty healthy male white Wistar rats were randomized into four experimental groups of 20 animals each: In the transected group (TC), the left sciatic nerve was transected and nerve cut ends were fixed in the adjacent muscle. In the treatment group the defect was bridged using an artery graft (AG/Keto) filled with 10 microliter ketoprofen (0.1 mg/kg). In the artery graft group (AG), the graft was filled with phosphated-buffer saline alone. In the sham-operated group (SHAM), the sciatic nerve was exposed and manipulated. Each group was subdivided into four subgroups of five animals each and regenerated nerve fibres were studied at 4, 8, 12 and 16 weeks post operation. Behavioural testing, sciatic nerve functional study, gastrocnemius muscle mass and morphometric indices showed earlier regeneration of axons in AG/Keto than in AG group (p < 0.05). Immunohistochemical study clearly showed more positive location of reactions to S-100 in AG/Keto than in AG group. When loaded in an artery graft, ketoprofen improved functional recovery and morphometric indices of the sciatic nerve. Local usage of this easily accessible therapeutic medicine is cost saving and avoids the problems associated with systemic administration.

  11. Relationship between occupational exposure to lead and local arterial stiffness and left ventricular diastolic function in individuals with arterial hypertension

    SciTech Connect

    Poreba, Rafal; Gac, Pawel; Poreba, Malgorzata; Antonowicz-Juchniewicz, Jolanta; Andrzejak, Ryszard

    2011-08-01

    Relationship between occupational exposure to lead and frequency of complications in persons with arterial hypertension has been poorly investigated. This study aimed at evaluation of the relationship between occupational exposure to lead and manifestation of an increased local arterial stiffness and left ventricular diastolic dysfunction. The studies included 105 men (mean age: 44.47 {+-} 9.12 years) with arterial hypertension, treated with hypotensive drugs: group I - men occupationally exposed to lead (n = 53), and group II - men not exposed to lead (n = 52). In echocardiographic examination, the left ventricular diastolic dysfunction was diagnosed significantly more frequently in group I than in group II. In eTracking examination mean values of stiffness parameter ({beta}), augmentation index (AI) and one-point pulse wave velocity (PWV-{beta}) were significantly higher and mean values of arterial compliance (AC) were significantly lower in group I than in group II. The logistic regression showed that in the group of persons with arterial hypertension occupationally exposed to lead a more advanced age, higher blood lead concentration and higher mean values of augmentation index represent independent risk factors of left ventricular diastolic dysfunction. The multifactorial regression showed that amongst persons with arterial hypertension occupationally exposed to lead higher blood zinc protoporphyrin concentration, a more advanced age and higher value of body mass index (BMI) represent independent risk factors of an increased local arterial stiffness. In summary, we should note that in the group of persons with arterial hypertension occupationally exposed to lead the study has demonstrated a significantly more frequent manifestation of left ventricular diastolic dysfunction and an increase in local arterial stiffness. - Highlights: > Amongst persons with AH exposed to Pb higher ZnPP represent independent risk factor of increased local arterial stiffness

  12. Uterine artery function in pregnant rats fed a diet supplemented with animal lard.

    PubMed

    Taylor, P D; Khan, I Y; Lakasing, L; Dekou, V; O'Brien-Coker, I; Mallet, A I; Hanson, M A; Poston, L

    2003-05-01

    We hypothesised that maternal uterine artery vascular dysfunction could contribute to cardiovascular dysfunction in offspring of rats fed a diet rich in fat. Sprague-Dawley rats were fed for 10 days prior to pregnancy and throughout gestation either: (a) a control breeding diet, or (b) the same diet supplemented with 20 % w/w lard, vitamins, essential micronutrients and protein to control values. At 20 days gestation vascular function was assessed in uterine arteries and third-order mesenteric arteries. Vascular reactivity in response to application of potassium, noradrenaline, the thromboxane analogue U46619, acetylcholine and nitric oxide was assessed. Maternal plasma concentrations of factors likely to contribute to endothelial dysfunction were measured. Maximum acetylcholine-induced relaxation was impaired in the mesenteric arteries of the lard-fed dams (max % relaxation: lard-fed, 69.7 +/- 6.48; control, 85.37 +/- 2.69, P = 0.03). Uterine artery vascular function was similar in the two groups (max % acetylcholine-induced relaxation: lard-fed, 73.7 +/- 4.01; control, 77.5 +/- 4.72, P = 0.98). Concentrations of plasma lipids, 8-epi-PGF(2alpha) and leptin were normal, whereas insulin and corticosterone concentrations were raised in the lard-fed group (insulin (ng ml(-1)): lard-fed, 8.04 +/- 0.47; control, 1.35 +/- 0.37, P < 0.0001; corticosterone (ng ml(-1)): lard-fed, 1164.0 +/- 170.9; control, 541.9 +/- 96.3, P = 0.005). Fetal and placental weights were reduced in lard-fed dams (fetus (g): lard-fed, 4.27 +/- 0.38; control, 2.96 +/- 0.40, P = 0.025; placenta (g): lard-fed, 0.72 +/- 0.06; control, 0.57 +/- 0.04, P = 0.05). Cardiovascular dysfunction in offspring is not associated with reduced uterine artery endothelial function but is associated with activation of the hypothalamic-pituitary-adrenal axis, hyperinsulinaemia and fetoplacental growth retardation.

  13. Effects of repeated long duration +2Gz load on man's cardiovascular function.

    PubMed

    Iwasaki, K; Hirayanagi, K I; Sasaki, T; Kinoue, T; Ito, M; Miyamoto, A; Igarashi, M; Yajima, K

    1998-01-01

    Usefulness of a short-arm human centrifuge is expected when it is used in space as a countermeasure against cardiovascular deconditioning, problem of bone-calcium metabolism, etc. However, nothing is solidly established regarding the most desirable program for artificial G application. Accordingly, this study was designed to analytically evaluate the effects of repeated long duration +Gz load on human cardiovascular function. Recently heart rate spectral analysis has been recognized as a powerful tool for quantitatively evaluating parasympathetic and sympathetic activity separately in human. It is reported that power of the high frequency component (HF-p) is mediated selectively by parasympathetic activity and the power ratio of low to high frequency components(LF/HF) is indicative of cardiac sympathetic activity or cardiac sympathovagal balance. Sequence method is developed to examine spontaneous baroreceptor reflex sensitivity (BRS). We studied cardiovascular control function by using these methods in 9 healthy men before and after 7 days of daily repeated 1hour +2Gz load. When compared with the data of pre-G load period, post-G load period, decrease of HR, increases of HF-p and BRS were statistically significant. SBP, DBP and LF/HF tended to decrease, however, these changes were not statistically significant. This results indicate that repeated +2Gz load increases parasympathetic activity and arterial baroreceptor-cardiac reflex sensitivity. In recent years, many investigators suggest that space flight and head-down bedrest leads to impaired baroreceptor-cardiac reflex responses and decrease of parasympathetic activity, which may contribute to orthostatic intolerance. So our results suggest that daily repeated 1hour +2Gz load would be useful in preventing post-flight orthostatic intolerance.

  14. Effects of repeated long duration +2Gz load on man's cardiovascular function

    NASA Astrophysics Data System (ADS)

    Iwasaki, Ken-ichi; Hirayanagi, Kaname; Sasaki, Tsuyoshi; Kinoue, Takaaki; Ito, Masao; Miyamoto, Akira; Igarashi, Makoto; Yajima, Kazuyoshi

    Usefulness of a short-arm human centrifuge is expected when it is used in space as a countermeasure against cardiovascular deconditioning, problem of bone-calcium metabolism, etc. However, nothing is solidly established regarding the most desirable program for artificial G application. Accordingly, this study was designed to analytically evaluate the effects of repeated long duration +Gz load on human cardiovascular function. Recently heart rate spectral analysis has been recognized as a powerful tool for quantitatively evaluating parasympathetic and sympathetic activity separately in human. It is reported that power of the high frequency component (HF-p) is mediated selectively by parasympathetic activity and the power ratio of low to high frequency components(LF/HF) is indicative of cardiac sympathetic activity or cardiac sympathovagal balance. Sequence method is developed to examine spontaneous baroreceptor reflex sensitivity (BRS). We studied cardiovascular control function by using these methods in 9 healthy men before and after 7 days of daily repeated 1hour +2Gz load. When compared with the data of pre-G load period, post-G load period, decrease of HR, increases of HF-p and BRS were statistically significant. SBP, DBP and LF/HF tended to decrease, however, these changes were not statistically significant. This results indicate that repeated +2Gz load increases parasympathetic activity and arterial baroreceptor-cardiac reflex sensitivity. In recent years, many investigators suggest that space flight and head-down bedrest leads to impaired baroreceptor-cardiac reflex responses and decrease of parasympathetic activity, which may contribute to orthostatic intolerance. So our results suggest that daily repeated 1hour +2Gz load would be useful in preventing post-flight orthostatic intolerance.

  15. Hepatic artery duplex Doppler ultrasound in severe alcoholic hepatitis and correlation with Maddrey's discriminant function.

    PubMed

    Abhilash, Haridas; Mukunda, Madhavan; Sunil, Premaletha; Devadas, Krishnadas; Vinayakumar, Katoor Ramakrishnan Nair

    2015-01-01

    Alcoholic hepatitis is associated with altered hepatic artery hemodynamics. Maddrey's discriminant function (MDF) can identify patients with poor prognosis (DF >32). We studied hepatic artery hemodynamic parameters of hepatic artery diameter (HAD), resistive index (RI) and pulsatility index (PI) in severe acute alcoholic hepatitis (SAAH) and for the presence of correlation of parameters with severity factor MDF. A total of 20 consecutive SAAH patients defined as MDF >32 and a group of 20 alcoholic cirrhosis patients without alcoholic hepatitis formed the two study groups. Hepatic artery Doppler parameters HAD, RI, PI were determined after admission in the Gastroenterology Department, Government Medical College, Thiruvananthapuram, India. MDF score of SAAH was calculated at the time of admission to the hospital. The mean HAD showed statistically significant increase in SAAH compared with cirrhosis (3.96±0.51 vs. 2.86±0.41, P<0.001). There was statistically significant decrease in mean RI (0.49±0.08 vs. 0.81±0.09, P<0.001) and mean PI (1.67±0.13 vs. 1.80±0.13, P<0.001) in SAAH compared with alcoholic cirrhosis. Statistically significant correlation between MDF and HAD (r=0.63, P<0.003) was found in SAAH. On linear regression, 36% of the variability in MDF could be independently predicted by HAD. Hepatic artery parameters of HAD, RI, PI had a significant difference in SAAH compared with alcoholic cirrhosis patients thereby being useful as a diagnostic tool. HAD showed correlation with MDF score assessing the severity of alcoholic hepatitis and may be a useful non-invasive prognostic tool.

  16. Mild central chemoreflex activation does not alter arterial baroreflex function in healthy humans

    PubMed Central

    Simmons, Grant H; Manson, Julie M; Halliwill, John R

    2007-01-01

    We have previously shown that activation of peripheral chemoreceptors with isocapnic hypoxia resets arterial baroreflex control of heart rate and sympathetic vasoconstrictor outflow to higher pressures, without changes in baroreflex gain. We tested the hypothesis that activation of central chemoreceptors with mild hyperoxic hypercapnia also causes resetting of the arterial baroreflex, but that this resetting would not occur with matched volume and frequency hyperpnoea. Baroreflex control of heart rate (n = 16) and muscle sympathetic nerve activity (microneurography; n = 11) was assessed in healthy men and women, age 20–33 years, using the modified Oxford technique during hyperoxic eucapnia, hyperoxic hyperpnoea and hyperoxic hypercapnia (end-tidal PCO2+ 5 mmHg above eucapnia). Baroreflex trials were separated by 30 min of rest. While neither hyperpnoea nor hypercapnia changed mean arterial pressure (92.0 ± 1.8 during eucapnia versus 91.0 ± 1.2 and 90.7 ± 1.4 mmHg during hyperpnoea and hypercapnia; P = 0.427) or muscle sympathetic nerve activity (2301 ± 687 during eucapnia versus 2959 ± 987 and 2272 ± 414 total integrated units min−1 during hyperpnoea and hypercapnia; P = 0.653), heart rate was increased from 59.3 ± 2.7 during eucapnia to 63.2 ± 3.0 and 62.4 ± 2.8 beats min−1 during hyperpnoea and hypercapnia (both P < 0.017). Baroreflex gain was not altered by hyperpnoea or hypercapnia. Thus, acute activation of central chemoreceptors with mild hyperoxic hypercapnia does not affect arterial pressure, sympathetic vasoconstrictor outflow, or baroreflex gain. Heart rate is elevated during hyperoxic hypercapnia, but this response is not different from the increase in heart rate produced by matched volume and frequency hyperpnoea. Therefore, mild activation of central chemoreceptors does not appear to alter arterial baroreflex function. PMID:17640930

  17. Effects of weight loss on structural and functional alterations of subcutaneous small arteries in obese patients.

    PubMed

    De Ciuceis, Carolina; Porteri, Enzo; Rizzoni, Damiano; Corbellini, Claudia; La Boria, Elisa; Boari, Gianluca E M; Pilu, Annamaria; Mittempergher, Francesco; Di Betta, Ernesto; Casella, Claudio; Nascimbeni, Riccardo; Rosei, Claudia Agabiti; Ruggeri, Giuseppina; Caimi, Luigi; Rosei, Enrico Agabiti

    2011-07-01

    Structural alterations of subcutaneous small resistance arteries, as indicated by an increased media:lumen ratio, are frequently present in hypertensive and/or diabetic patients and may represent the earliest alteration observed. In addition, media:lumen ratios of small arteries have a strong prognostic significance. However, no data are available about the structure of small resistance arteries of obese patients, particularly after weight loss. We have investigated 27 patients with severe obesity. Twelve of them were normotensive, and 15 were hypertensive. All of the obese patients underwent bariatric surgery. We compared results obtained with those observed in 13 normotensive lean controls and in 13 hypertensive lean patients. All of the subjects and patients underwent a biopsy of subcutaneous fat during surgical intervention. In 8 obese patients, a second biopsy was obtained after consistent weight loss, during a surgical intervention for abdominoplasty. Subcutaneous small resistance arteries were dissected and mounted on a wire myograph, and structural parameters were measured. A concentration-response curve to acetylcholine was performed to evaluate endothelial function. Obese patients, independent from the presence of hypertension, show the presence of an increased media:lumen ratio and media cross-sectional area, together with an impaired endothelial-dependent vasodilatation. After surgical correction of obesity and consistent weight loss, a significant improvement of microvascular structure and of some oxidative stress/inflammation markers were observed. In conclusion, our data suggest that the presence of obesity is associated with structural alterations of subcutaneous small resistance arteries, mainly characterized by hypertrophic remodeling. Weight loss may improve microvascular structure.

  18. Acute effects of self-myofascial release using a foam roller on arterial function.

    PubMed

    Okamoto, Takanobu; Masuhara, Mitsuhiko; Ikuta, Komei

    2014-01-01

    Flexibility is associated with arterial distensibility. Many individuals involved in sport, exercise, and/or fitness perform self-myofascial release (SMR) using a foam roller, which restores muscles, tendons, ligaments, fascia, and/or soft-tissue extensibility. However, the effect of SMR on arterial stiffness and vascular endothelial function using a foam roller is unknown. This study investigates the acute effect of SMR using a foam roller on arterial stiffness and vascular endothelial function. Ten healthy young adults performed SMR and control (CON) trials on separate days in a randomized controlled crossover fashion. Brachial-ankle pulse wave velocity (baPWV), blood pressure, heart rate, and plasma nitric oxide (NO) concentration were measured before and 30 minutes after both SMR and CON trials. The participants performed SMR of the adductor, hamstrings, quadriceps, iliotibial band, and trapezius. Pressure was self-adjusted during myofascial release by applying body weight to the roller and using the hands and feet to offset weight as required. The roller was placed under the target tissue area, and the body was moved back and forth across the roller. In the CON trial, SMR was not performed. The baPWV significantly decreased (from 1,202 ± 105 to 1,074 ± 110 cm·s-1) and the plasma NO concentration significantly increased (from 20.4 ± 6.9 to 34.4 ± 17.2 μmol·L-1) after SMR using a foam roller (both p < 0.05), but neither significantly differed after CON trials. These results indicate that SMR using a foam roller reduces arterial stiffness and improves vascular endothelial function.

  19. Effects of cranberry juice consumption on vascular function in patients with coronary artery disease123

    PubMed Central

    Dohadwala, Mustali M; Holbrook, Monika; Hamburg, Naomi M; Shenouda, Sherene M; Chung, William B; Titas, Megan; Kluge, Matthew A; Wang, Na; Palmisano, Joseph; Milbury, Paul E; Blumberg, Jeffrey B; Vita, Joseph A

    2011-01-01

    Background: Cranberry juice contains polyphenolic compounds that could improve endothelial function and reduce cardiovascular disease risk. Objective: The objective was to examine the effects of cranberry juice on vascular function in subjects with coronary artery disease. Design: We completed an acute pilot study with no placebo (n = 15) and a chronic placebo-controlled crossover study (n = 44) that examined the effects of cranberry juice on vascular function in subjects with coronary artery disease. Results: In the chronic crossover study, subjects with coronary heart disease consumed a research preparation of double-strength cranberry juice (54% juice, 835 mg total polyphenols, and 94 mg anthocyanins) or a matched placebo beverage (480 mL/d) for 4 wk each with a 2-wk rest period between beverages. Beverage order was randomly assigned, and participants refrained from consuming other flavonoid-containing beverages during the study. Vascular function was measured before and after each beverage, with follow-up testing ≥12 h after consumption of the last beverage. Mean (±SD) carotid-femoral pulse wave velocity, a measure of central aortic stiffness, decreased after cranberry juice (8.3 ± 2.3 to 7.8 ± 2.2 m/s) in contrast with an increase after placebo (8.0 ± 2.0 to 8.4 ± 2.8 m/s) (P = 0.003). Brachial artery flow-mediated dilation, digital pulse amplitude tonometry, blood pressure, and carotid-radial pulse wave velocity did not change. In the uncontrolled pilot study, we observed improved brachial artery flow-mediated dilation (7.7 ± 2.9% to 8.7 ± 3.1%, P = 0.01) and digital pulse amplitude tonometry ratio (0.10 ± 0.12 to 0.23 ± 0.16, P = 0.001) 4 h after consumption of a single 480-mL portion of cranberry juice. Conclusions: Chronic cranberry juice consumption reduced carotid femoral pulse wave velocity—a clinically relevant measure of arterial stiffness. The uncontrolled pilot study suggested an acute benefit; however, no chronic effect on measures of

  20. Association of sarcoidosis with endothelial function, arterial wall properties, and biomarkers of inflammation.

    PubMed

    Siasos, Gerasimos; Tousoulis, Dimitris; Gialafos, Elias; Oikonomou, Evangelos; Zaromitidou, Marina; Aggeli, Constantina; Korompelis, Porfyrios; Kallianos, Anastasios; Rapti, Aggeliki; Zisimos, Konstantinos; Marinos, Georgios; Stefanadis, Christodoulos; Papavassiliou, Athanasios G

    2011-06-01

    Sarcoidosis is an inflammatory disease, which may affect vascular function. The study was designed to assess the impact of sarcoidosis on endothelial function and arterial stiffness. Eighty-seven sarcoidosis patients and eighty-seven matched healthy subjects (Cl) were included in the study. Sarcoidosis patients were divided into two groups. Group 1 included patients never treated and group 2 included patients receiving cortisone treatment. Endothelial function was evaluated by flow-mediated dilatation (FMD). Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness and augmentation index (AI75) as a measure of arterial wave reflections. Serum levels of soluble intercellular adhesion molecule-1 and tumor necrosis factor-α (TNF-α), were measured. In the totality of the population, sarcoidosis patients had significantly lower FMD (P < 0.01) and significantly higher AI75 (P < 0.05). There was also a significant difference, between group 1, and Cl in FMD and AI75, but there was no difference between group 2 and Cl in FMD and AI75. AI75 values were significantly correlated with serum levels of intercellular adhesion molecule-1 (ICAM-1) (r = 0.370, P < 0.01) and TNF-α (r = 0.219, P = 0.049). In the present study, we have shown that sarcoidosis patients have impaired endothelial function and increased arterial stiffness. Sarcoidosis patients on cortisone treatment had no differences compared to controls on the vascular parameters. Moreover, there was a significant correlation between inflammatory process and vascular function impairment. These findings indicate that sarcoidosis patients have impaired vascular function and increased inflammatory status, which may improve with cortisone treatment.

  1. Arterial-cardiac baroreflex function: insights from repeated squat-stand maneuvers.

    PubMed

    Zhang, Rong; Claassen, Jurgen A H R; Shibata, Shigeki; Kilic, Sinem; Martin-Cook, Kristin; Diaz-Arrastia, Ramon; Levine, Benjamin D

    2009-07-01

    To assess baroreflex function under closed-loop conditions, a new approach was used to generate large and physiological perturbations in arterial pressure. Blood pressure (BP) and R-R interval were recorded continuously in 20 healthy young (33 +/- 8 yr) and eight elderly subjects (66 +/- 6 yr). Repeated squat-stand maneuvers at the frequencies of 0.05 and 0.1 Hz were performed to produce periodic oscillations in BP to provoke the baroreflex. To assess the effects of the muscle reflex and/or central command on the baroreflex, passive squat-stand maneuvers were conducted using a pulley system to assist changes in body position. Transfer function between changes in BP and R-R interval was estimated to assess the arterial-cardiac baroreflex. Relative to resting conditions, large and coherent oscillations in BP and R-R interval were produced during both active and passive squat-stand maneuvers. However, changes in BP were smaller during passive than during active maneuvers. Changes in R-R interval were reduced commensurately. Therefore, transfer function gain did not change between the two maneuvers. Compared with the young, transfer function gain was reduced and the phase became more negative in the elderly, demonstrating the well-known effects of aging on reducing baroreflex sensitivity. Collectively, these findings suggest that the changes in R-R interval elicited by BP perturbations during squat-stand maneuvers are mediated primarily by a baroreflex mechanism. Furthermore, baroreflex function can be assessed using the transfer function method during large perturbations in arterial pressure.

  2. Can selective arterial clamping with fluorescence imaging preserve kidney function during robotic partial nephrectomy?

    PubMed Central

    McClintock, Tyler R.; Bjurlin, Marc A.; Wysock, James S.; Borofsky, Michael S.; Marien, Tracy P.; Okoro, Chinonyerem; Stifelman, Michael D.

    2015-01-01

    Objectives To compare renal functional outcomes in robotic partial nephrectomy (RPN) with selective arterial clamping guided by near infrared fluorescence (NIRF) imaging to a matched cohort of patients who underwent RPN without selective arterial clamping and NIRF imaging. Methods From April 2011 to December 2012, NIRF imaging-enhanced RPN with selective clamping was utilized in 42 cases. Functional outcomes of successful cases were compared with a cohort of patients, matched by tumor size, preoperative eGFR, functional kidney status, age, sex, body mass index, and American Society of Anesthesiologists score, who underwent RPN without selective clamping and NIRF imaging. Results In matched-pair analysis, selective clamping with NIRF was associated with superior kidney function at discharge, as demonstrated by postoperative eGFR (78.2 vs 68.5 ml/min per 1.73m2; P=0.04), absolute reduction of eGFR (−2.5 vs −14.0 ml/min per 1.73m2; P<0.01) and percent change in eGFR (−1.9% vs −16.8%, P<0.01). Similar trends were noted at three month follow up but these differences became non-significant (P[eGFR]=0.07], P[absolute reduction of eGFR]=0.10, and P[percent change in eGFR]=0.07). In the selective clamping group, a total of four perioperative complications occurred in three patients, all of which were Clavien I-III. Conclusion Utilization of NIRF imaging was associated with improved short-term renal functional outcomes when compared to RPN without selective arterial clamping and NIRF imaging. With this effect attenuated at later follow-up, randomized prospective studies and long-term assessment of kidney-specific functional outcomes are needed to further assess the benefits of this technology. PMID:24909960

  3. Modelling Arterial Pressure Waveforms Using Gaussian Functions and Two-Stage Particle Swarm Optimizer

    PubMed Central

    Zhuang, Tao; Zhao, Lina; Chang, Faliang; Liu, Changchun; Wei, Shoushui; Li, Qiqiang

    2014-01-01

    Changes of arterial pressure waveform characteristics have been accepted as risk indicators of cardiovascular diseases. Waveform modelling using Gaussian functions has been used to decompose arterial pressure pulses into different numbers of subwaves and hence quantify waveform characteristics. However, the fitting accuracy and computation efficiency of current modelling approaches need to be improved. This study aimed to develop a novel two-stage particle swarm optimizer (TSPSO) to determine optimal parameters of Gaussian functions. The evaluation was performed on carotid and radial artery pressure waveforms (CAPW and RAPW) which were simultaneously recorded from twenty normal volunteers. The fitting accuracy and calculation efficiency of our TSPSO were compared with three published optimization methods: the Nelder-Mead, the modified PSO (MPSO), and the dynamic multiswarm particle swarm optimizer (DMS-PSO). The results showed that TSPSO achieved the best fitting accuracy with a mean absolute error (MAE) of 1.1% for CAPW and 1.0% for RAPW, in comparison with 4.2% and 4.1% for Nelder-Mead, 2.0% and 1.9% for MPSO, and 1.2% and 1.1% for DMS-PSO. In addition, to achieve target MAE of 2.0%, the computation time of TSPSO was only 1.5 s, which was only 20% and 30% of that for MPSO and DMS-PSO, respectively. PMID:24967415

  4. Characterization of endothelial function in the brachial artery via affine registration of ultrasonographic image sequences

    NASA Astrophysics Data System (ADS)

    Lamata, Pablo; Laclaustra, Martin; Frangi, Alejandro F.

    2003-05-01

    The assessment and characterization of the endothelial function is a current research topic as it may play an important role in the diagnosis of cardiovascular diseases. Flow mediated dilatation may be used to investigate endothelial function, and B-mode ultrasonography is a cheap and non-invasive way to assess the vasodilation response. Computerized analysis techniques are very desirable to give higher accuracy and objectivity to the measurements. A new method is presented that solves some limitations of existing methods, which in general depend on accurate edge detection of the arterial wall. This method is based on a global image analysis strategy. The arterial vasodilation between two frames is modeled by a superposition of a rigid motion model and a stretching perpendicular to the artery. Both transformation models are recovered using an image registration algorithm based on normalized mutual information and a multi-resolution search framework. Temporal continuity of in the variation of the registration parameters is enforced with a Kalman filter, since the dilation process is known to be a gradual and continuous physiological phenomenon. The proposed method presents a negligible bias when compared with manual assessment. It also eliminates artifacts introduced by patient and probe motion, thus improving the accuracy of the measurements. Finally, it is also robust to typical problems of ultrasound, like speckle noise and poor image quality.

  5. First-ever ischemic stroke in elderly patients: predictors of functional outcome following carotid artery stenting

    PubMed Central

    Lin, Chih-Ming; Chang, Yu-Jun; Liu, Chi-Kuang; Yu, Cheng-Sheng; Lu, Henry Horng-Shing

    2016-01-01

    Age is an important risk factor for stroke, and carotid artery stenosis is the primary cause of first-ever ischemic stroke. Timely intervention with stenting procedures can effectively prevent secondary stroke; however, the impact of stenting on various periprocedural physical functionalities has never been thoroughly investigated. The primary aim of this study was to investigate whether prestenting characteristics were associated with long-term functional outcomes in patients presenting with first-ever ischemic stroke. The secondary aim was to investigate whether patient age was an important factor in outcomes following stenting, measured by the modified Rankin scale (mRS). In total, 144 consecutive patients with first-ever ischemic stroke who underwent carotid artery stenting from January 2010 to November 2014 were included. Clinical data were obtained by review of medical records. The Barthel index (BI) and mRS were used to assess disability before stenting and at 12-month follow-up. In total, 72/144 patients showed improvement (mRS[+]), 71 showed stationary and one showed deterioration in condition (mRS[−]). The prestenting parameters, ratio of cerebral blood volume (1.41 vs 1.2 for mRS[−] vs mRS[+]), BI (75 vs 85), and high-sensitivity C-reactive protein (hsCRP 5.0 vs 3.99), differed significantly between the two outcome groups (P<0.05). The internal carotid artery/common carotid artery ratio (P=0.011), BI (P=0.019), ipsilateral internal carotid artery resistance index (P=0.003), and HbA1c (P=0.039) were all factors significantly associated with patient age group. There was no significant association between age and poststenting outcome measured by mRS with 57% of patients in the ≥75 years age group showing mRS(−) and 43% showing mRS(+) (P=0.371). Our findings indicate that in our elderly patient series, carotid artery stenting may benefit a significant proportion of carotid stenotic patients regardless of age. Ratio of cerebral blood volume, BI, and

  6. Use of functional mass in renal scintigraphy to detect segmental arterial lesions

    SciTech Connect

    Stibolt, T.B. Jr.; Bacher, J.D.; Dunnick, N.R.; Lock, A.; Jones, A.E.; Bailey, J.J.

    1982-04-01

    Renography using a gamma camera, a minicomputer, (/sup 123/I)orthoiodohippurate ((/sup 123/I)OIH), and a canine model was employed to evaluate computer-generated maps of regional renal function. Renograms were obtained before and after ligations of the right renal arterial branch in four dogs, with subsequent angiographic and histologic confirmation of the lesions. Postoperative time-activity curves were normal. Washout and persistence index in three of four right kidneys showed regional abnormality. Functional renal mapping may provide a clinical technique for evaluating human renal vascular hypertension.

  7. Bifurcations in a nonlinear model of the baroreceptor-cardiac reflex

    NASA Astrophysics Data System (ADS)

    Seidel, H.; Herzel, H.

    1998-04-01

    We investigate the dynamic properties of a nonlinear model of the human cardio-baroreceptor control loop. As a new feature we use a phase effectiveness curve to describe the experimentally well-known phase dependency of the cardiac pacemaker's sensitivity to neural activity. We show that an increase of sympathetic time delays leads via a Hopf bifurcation to sustained heart rate oscillations. For increasing baroreflex sensitivity or for repetitive vagal stimulation we observe period-doubling, toroidal oscillations, chaos, and entrainment between the rhythms of the heart and the control loop. The bifurcations depend crucially on the involvement of the cardiac pacemaker's phase dependency. We compare the model output with experimental data from electrically stimulated anesthetized dogs and discuss possible implications for cardiac arrhythmias.

  8. Measurement of arterial input function of 17O water tracer in rat carotid artery by using a region-defined (REDE) implanted vascular RF coil.

    PubMed

    Zhang, Xiaoliang; Zhu, Xiao-Hong; Tian, Runxia; Zhang, Yi; Merkle, Hellmut; Chen, Wei

    2003-07-01

    A method of determining arterial input function (AIF) by continuously detecting the (17)O MR signal changes of (17)O-labeled water tracer in the rat carotid artery using a region-defined (REDE) implanted vascular RF coil at 9.4 Tesla is reported. This coil has a compact physical size of 1 mm inner diameter, 3 mm outer diameter and 11 mm in length. It can be readily implanted into the rat neck and wrapped around the rat carotid artery for achieving adequate MR detection sensitivity for determining AIF with minimal surgical trauma. Water phantom and in vivo MR experiments were conducted for validating the coil's performance. A signal-to-noise ratio of approximately 20:1 was achieved for the (17)O signal acquired from naturally abundant H(2)(17)O in a small amount of blood (approximately 7 microl) inside the rat carotid artery with an acquisition time of 11 s. The REDE RF coil design electromagnetically isolates the rat carotid artery from surrounding tissues and ensures that the MR signal detected by the RF coil is only attributable to the artery blood. It also minimizes the electromagnetic coupling between the implanted RF coil and a head surface coil tuned at the same operating frequency (two-coil configuration). This configuration allowed simultaneous measurements of dynamic changes of (17)O MR signal of the H(2)(17)O tracer in both rat carotid artery and brain. Compared to most contemporary MR approaches, the REDE implanted RF provides a simple, accurate, and promising solution for determination of AIF in small experimental animals.

  9. Intima-media thickness of brachial artery, vascular function, and cardiovascular risk factors.

    PubMed

    Iwamoto, Yumiko; Maruhashi, Tatsuya; Fujii, Yuichi; Idei, Naomi; Fujimura, Noritaka; Mikami, Shinsuke; Kajikawa, Masato; Matsumoto, Takeshi; Kihara, Yasuki; Chayama, Kazuaki; Noma, Kensuke; Nakashima, Ayumu; Higashi, Yukihito

    2012-09-01

    Cardiovascular diseases are associated with impaired flow-mediated vasodilation (FMD) and increase in carotid intima-media thickness (IMT). Both FMD and IMT are independent predictors for cardiovascular outcomes. When measuring FMD and nitroglycerine-induced vasodilation in the brachial artery, IMT can also be simultaneously assessed in the same brachial artery. The purpose of this study was to determine the relationships between IMT of the brachial artery, vascular function, and cardiovascular risk factors. We measured brachial IMT, FMD, and nitroglycerine-induced vasodilation by ultrasound in 388 subjects who underwent health examination (mean age, 45±22 years; age range, 19-86), including patients with cardiovascular diseases. Univariate regression analysis revealed that brachial IMT significantly correlated with age (r=0.71; P<0.001), body mass index (r=0.27; P<0.001), systolic blood pressure (r=0.40; P<0.001), diastolic blood pressure (r=0.31; P<0.001), heart rate (r=0.15; P=0.002), glucose level (r=0.18; P=0.01), and smoking pack-years (r=0.42; P<0.001), as well as Framingham risk score, a cumulative cardiovascular risk index for heart attack (r=0.49; P<0.001). FMD and nitroglycerine-induced vasodilation were inversely associated with brachial IMT (r=-0.39, P<0.001; r=-0.32, P<0.001, respectively). In addition, there was a significant relationship between brachial IMT and carotid IMT (r=0.58; P<0.001). Multivariate analysis revealed that age, sex, hypertension, and brachial artery diameter were independent predictors of brachial IMT. These findings suggest that brachial IMT may be a marker of the grade of atherosclerosis and may be used as a marker of vascular function, providing additive information for stratifying subjects with cardiovascular risk factors.

  10. Deep-breathing exercises reduce atelectasis and improve pulmonary function after coronary artery bypass surgery.

    PubMed

    Westerdahl, Elisabeth; Lindmark, Birgitta; Eriksson, Tomas; Friberg, Orjan; Hedenstierna, Göran; Tenling, Arne

    2005-11-01

    To investigate the effects of deep-breathing exercises on pulmonary function, atelectasis, and arterial blood gas levels after coronary artery bypass graft (CABG) surgery. In a prospective, randomized trial, patients performing deep-breathing exercises (n = 48) were compared to a control group (n = 42) who performed no breathing exercises postoperatively. Patient management was similar in the groups in terms of assessment, positioning, and mobility. The patients in the deep-breathing group were instructed to perform breathing exercises hourly during daytime for the first 4 postoperative days. The exercises consisted of 30 slow, deep breaths performed with a positive expiratory pressure blow-bottle device (+ 10 cm H(2)O). Spirometric measurements, spiral CT (three transverse levels), arterial blood gas analysis, and scoring of subjective experience of the breathing exercises were performed on the fourth postoperative day. Atelectasis was only half the size in the deep-breathing group compared to the control group, amounting to 2.6 +/- 2.2% vs 4.7 +/- 5.7% (p = 0.045) at the basal level and 0.1 +/- 0.2% vs 0.3 +/- 0.5% (mean +/- SD) [p = 0.01] at the apical level. Compared to the control subjects, the patients in the deep-breathing group had a significantly smaller reduction in FVC (to 71 +/- 12%, vs 64 +/- 13% of the preoperative values; p = 0.01) and FEV(1) (to 71 +/- 11%, vs 65 +/- 13% of the preoperative values; p = 0.01). Arterial oxygen tension, carbon dioxide tension, fever, or length of ICU or hospital stay did not differ between the groups. In the deep-breathing group, 72% of the patients experienced a subjective benefit from the exercises. Patients performing deep-breathing exercises after CABG surgery had significantly smaller atelectatic areas and better pulmonary function on the fourth postoperative day compared to a control group performing no exercises.

  11. Uteroplacental insufficiency and lactational environment separately influence arterial stiffness and vascular function in adult male rats.

    PubMed

    Tare, Marianne; Parkington, Helena C; Bubb, Kristen J; Wlodek, Mary E

    2012-08-01

    Early life environmental influences can have lifelong consequences for health, including the risk of cardiovascular disease. Uteroplacental insufficiency causes fetal undernutrition and impairs fetal growth. Previously we have shown that uteroplacental insufficiency is associated with impaired maternal mammary development, compromising postnatal growth leading to hypertension in male rat offspring. In this study we investigated the roles of prenatal and postnatal nutritional environments on endothelial and smooth muscle reactivity and passive wall stiffness of resistance arteries of male rat offspring. Fetal growth restriction was induced by maternal bilateral uterine vessel ligation (restricted) on day 18 of pregnancy. Control offspring were from mothers that had sham surgery (control) and another group from mothers with their litter size reduced (reduced; litter size reduced to 5 at birth, equivalent to the restricted group). On postnatal day 1, offspring (control, restricted, and reduced) were cross-fostered onto control or restricted mothers. At 6 months, mesenteric and femoral arteries were studied using wire and pressure myography. In restricted-on-restricted rats, wall stiffness was increased, and sensitivity to phenylephrine and relaxation evoked by endothelium-derived hyperpolarizing factor and sodium nitroprusside were impaired in mesenteric arteries. In femoral arteries, relaxation to sodium nitroprusside was reduced, whereas wall stiffness was unaltered. Cross-fostering restricted offspring onto control mothers alleviated deficits in vascular stiffness and reactivity. Control or reduced offspring who suckled a restricted mother had marked vascular stiffening. In conclusion, prenatal and early postnatal environments separately influence vascular function and stiffness. Furthermore, the early postnatal lactational environment is a determinant of later cardiovascular function.

  12. Human investigations into the arterial and cardiopulmonary baroreflexes during exercise.

    PubMed

    Fadel, Paul J; Raven, Peter B

    2012-01-01

    After considerable debate and key experimental evidence, the importance of the arterial baroreflex in contributing to and maintaining the appropriate neural cardiovascular adjustments to exercise is now well accepted. Indeed, the arterial baroreflex resets during exercise in an intensity-dependent manner to continue to regulate blood pressure as effectively as at rest. Studies have indicated that the exercise resetting of the arterial baroreflex is mediated by both the feedforward mechanism of central command and the feedback mechanism associated with skeletal muscle afferents (the exercise pressor reflex). Another perhaps less appreciated neural mechanism involved in evoking and maintaining neural cardiovascular responses to exercise is the cardiopulmonary baroreflex. The limited information available regarding the cardiopulmonary baroreflex during exercise provides evidence for a role in mediating sympathetic nerve activity and blood pressure responses. In addition, recent investigations have demonstrated an interaction between cardiopulmonary baroreceptors and the arterial baroreflex during dynamic exercise, which contributes to the magnitude of exercise-induced increases in blood pressure as well as the resetting of the arterial baroreflex. Furthermore, neural inputs from the cardiopulmonary baroreceptors appear to play an important role in establishing the operating point of the arterial baroreflex. This symposium review highlights recent studies in these important areas indicating that the interactions of four neural mechanisms (central command, the exercise pressor reflex, the arterial baroreflex and cardiopulmonary baroreflex) are integral in mediating the neural cardiovascular adjustments to exercise.

  13. Right heart function during simulated altitude in patients with pulmonary arterial hypertension

    PubMed Central

    Seccombe, Leigh M; Chow, Vincent; Zhao, Wei; Lau, Edmund M T; Rogers, Peter G; Ng, Austin C C; Veitch, Elizabeth M; Peters, Matthew J; Kritharides, Leonard

    2017-01-01

    Objective Patients with pulmonary arterial hypertension (PAH) are often recommended supplemental oxygen for altitude travel due to the possible deleterious effects of hypoxia on pulmonary haemodynamics and right heart function. This includes commercial aircraft travel; however, the direct effects and potential risks are unknown. Methods Doppler echocardiography and gas exchange measures were investigated in group 1 patients with PAH and healthy patients at rest breathing room air and while breathing 15.1% oxygen, at rest for 20 min and during mild exertion. Results The 14 patients with PAH studied were clinically stable on PAH-specific therapy, with functional class II (n=11) and III (n=3) symptoms when tested. Measures of right ventricular size and function were significantly different in the PAH group at baseline as compared to 7 healthy patients (p<0.04). There was no evidence of progressive right ventricular deterioration during hypoxia at rest or under exertion. Pulmonary arterial systolic pressure (PASP) increased in both groups during hypoxia (p<0.01). PASP in hypoxia correlated strongly with baseline PASP (p<0.01). Pressure of arterial oxygen correlated with PASP in hypoxia (p<0.03) but not at baseline, with three patients with PAH experiencing significant desaturation. The duration and extent of hypoxia in this study was tolerated well despite a mild increase in symptoms of breathlessness (p<0.01). Conclusions Non-invasive measures of right heart function in group 1 patients with PAH on vasodilator treatment demonstrated a predictable rise in PASP during short-term simulated hypoxia that was not associated with a deterioration in right heart function. PMID:28123765

  14. Evidence for a possible role of oxygen free radicals in the abnormal functional arterial vasomotion in insulin dependent diabetes.

    PubMed

    Ceriello, A; Quatraro, A; Caretta, F; Varano, R; Giugliano, D

    1990-01-01

    A functional arterial spasm, revealed by reduced post-ischemic response, is present in diabetic subjects with no overt evidence of vascular damage. The administration of three different antioxidant agents, vitamin C, thiopronine and glutathione, produces an increase of basal blood flow in both diabetic and normal subjects, and ameliorates significantly the vascular functional response in diabetes. These data suggest that free radicals may play a role in the regulation of arterial resistance in humans, and that a de-regulation of their action may be involved in the development of arterial dysfunction in diabetes.

  15. Impact of Intensive Physiotherapy on Cognitive Function after Coronary Artery Bypass Graft Surgery

    PubMed Central

    Cavalcante, Elder dos Santos; Magario, Rosmeiri; Conforti, César Augusto; Cipriano Júnior, Gerson; Arena, Ross; Carvalho, Antonio Carlos C.; Buffolo, Enio; Luna Filho, Bráulio

    2014-01-01

    Background Coronary artery bypass graft (CABG) is a standard surgical option for patients with diffuse and significant arterial plaque. This procedure, however, is not free of postoperative complications, especially pulmonary and cognitive disorders. Objective This study aimed at comparing the impact of two different physiotherapy treatment approaches on pulmonary and cognitive function of patients undergoing CABG. Methods Neuropsychological and pulmonary function tests were applied, prior to and following CABG, to 39 patients randomized into two groups as follows: Group 1 (control) – 20 patients underwent one physiotherapy session daily; and Group 2 (intensive physiotherapy) – 19 patients underwent three physiotherapy sessions daily during the recovery phase at the hospital. Non-paired and paired Student t tests were used to compare continuous variables. Variables without normal distribution were compared between groups by using Mann-Whitney test, and, within the same group at different times, by using Wilcoxon test. The chi-square test assessed differences of categorical variables. Statistical tests with a p value ≤ 0.05 were considered significant. Results Changes in pulmonary function were not significantly different between the groups. However, while Group 2 patients showed no decline in their neurocognitive function, Group 1 patients showed a decline in their cognitive functions (P ≤ 0.01). Conclusion Those results highlight the importance of physiotherapy after CABG and support the implementation of multiple sessions per day, providing patients with better psychosocial conditions and less morbidity. PMID:25352459

  16. Model-free arterial spin labelling for cerebral blood flow quantification: introduction of regional arterial input functions identified by factor analysis.

    PubMed

    Knutsson, Linda; Bloch, Karin Markenroth; Holtås, Stig; Wirestam, Ronnie; Ståhlberg, Freddy

    2008-05-01

    To identify regional arterial input functions (AIFs) using factor analysis of dynamic studies (FADS) when quantification of perfusion is performed using model-free arterial spin labelling. Five healthy volunteers and one patient were examined on a 3-T Philips unit using quantitative STAR labelling of arterial regions (QUASAR). Two sets of images were retrieved, one where the arterial signal had been crushed and another where it was retained. FADS was applied to the arterial signal curves to acquire the AIFs. Perfusion maps were obtained using block-circulant SVD deconvolution and regional AIFs obtained by FADS. In the volunteers, the ASL experiment was repeated within 24 h. The patient was also examined using dynamic susceptibility contrast MRI. In the healthy volunteers, CBF was 64+/-10 ml/[min 100 g] (mean+/-S.D.) in GM and 24+/-4 ml/[min 100 g] in WM, while the mean aBV was 0.94% in GM and 0.25% in WM. Good CBF image quality and reasonable quantitative CBF values were obtained using the combined QUASAR/FADS technique. We conclude that FADS may be a useful supplement in the evaluation of ASL data using QUASAR.

  17. Relation of arterial structure and function to left ventricular geometric patterns in hypertensive adults.

    PubMed

    Roman, M J; Pickering, T G; Schwartz, J E; Pini, R; Devereux, R B

    1996-09-01

    The present study sought to determine whether conduit artery structure and function vary according to the pattern of left ventricular adaptation to hypertension. Although left ventricular geometric pattern has been shown to predict cardiovascular events in hypertension, the arterial status in patients with the different patterns is unknown. We evaluated arterial structure and function by carotid ultrasound and applanation tonometry in 271 unmedicated hypertensive patients classified by echocardiography as having normal ventricular geometry (n = 176), concentric remodeling (n = 54), concentric hypertrophy (n = 16) or eccentric hypertrophy (n = 25). All groups were similar in age, gender distribution and body size. Patients with concentric and eccentric hypertrophy had similar blood pressures (mean 173/100 and 171/99 mm Hg, respectively) and left ventricular mass, but compared with patients with normal left ventricular geometry and concentric remodeling, only those with concentric hypertrophy had increased arterial wall thickness (0.96 +/- 0.20 vs. 0.80 +/- 0.18 mm, p < 0.05), end-diastolic diameter (6.38 +/- 0.97 vs. 5.76 +/- 0.87 mm, p < 0.05), cross-sectional area (22.1 +/- 5.71 vs. 16.6 +/- 5.4 mm(1)2 p < 0.05) and elastic modulus (713 +/- 265 vs. 471 +/- 241 dynes/cm2 x 10(-5), p < 0.05). Patients with concentric remodeling and eccentric hypertrophy had similar values for these measures (0.85 +/- 0.22 and 0.89 +/- 0.21 mm, 5.67 +/- 0.77 and 6.04 +/- 0.44 mm, 17.2 +/- 5.4 and 19.7 +/- 5.9 mm2, 558 +/- 263 and 614 +/- 257 dynes/cm2 x 10(-6), respectively), despite lower systolic blood pressures in the former group (156/94 mm Hg, p < 0.001). The prevalence of plaque was comparable in patients with concentric (56%) and eccentric (42%) hypertrophy and significantly greater than that in patients [corrected] with normal geometry (21%). Among patients with generally mild, uncomplicated systemic hypertension, arterial structure and function are most abnormal when

  18. The Effect of Elective Percutaneous Coronary Intervention of the Right Coronary Artery on Right Ventricular Function

    PubMed Central

    Nikdoust, Farahnaz; Tabatabaei, Seyed Abdolhosein; Shafiee, Akbar; Mostafavi, Atoosa; Mohamadi, Maryam; Mohammadi, Sareh

    2014-01-01

    Background: Right Ventricular (RV) dysfunction has been introduced as a predictor of mortality in acute myocardial infarction. Objectives: This study aimed to investigate the effect of right coronary revascularization on systolic and diastolic RV dysfunction. Patients and Methods: This study was conducted on unstable angina patients who were candidate for elective Percutaneous Revascularization Intervention (PCI) on the right coronary artery. The participants were initially evaluated by transthoracic echocardiography and tissue Doppler imaging prior to PCI and the RV function parameters were assessed. Echocardiography was repeated two months after PCI and the results were compared with baseline. Paired t-test was used to compare the pre- and post-procedural measurements. Besides, Pearson’s correlation was used to find out the linear association between the RV function parameters and Left Ventricular Ejection Fraction (LVEF). P value < 0.05 was considered as statistically significant. Results: This study was conducted on 30 patients (mean age = 60.00 ± 8.44 years; 24 [80%] males). In the pre-procedural echocardiography, 15 patients (50%) had normal RV function, 14 patients (46.7%) had grade-1 RV dysfunction, and only 1 patient (3.3%) had grade-2 RV dysfunction. Following PCI, however, all the patients had normal systolic and diastolic RV functions. Comparison of echocardiographic RV function parameters showed an improvement in both systolic and diastolic functional parameters of the RV. Nonetheless, no significant correlation was observed between these parameters and Left Ventricular (LV) function. Conclusions: A significant improvement was found in RV function, but not LV function, after right coronary PCI. Revascularization of the right coronary artery may be beneficial for the patients who suffer from RV failure due to ischemia. PMID:25614857

  19. Defining a local arterial input function for perfusion MRI using independent component analysis.

    PubMed

    Calamante, Fernando; Mørup, Morten; Hansen, Lars Kai

    2004-10-01

    Quantification of cerebral blood flow (CBF) using dynamic-susceptibility contrast MRI relies on the deconvolution of the arterial input function (AIF), which is commonly estimated from the signal changes in a major artery. However, it has been shown that the presence of bolus delay/dispersion between the artery and the tissue of interest can be a significant source of error. These effects could be minimized if a local AIF were used, although the measurement of a local AIF can be problematic. This work describes a new methodology to define a local AIF using independent component analysis (ICA). The methodology was tested on data from patients with various cerebrovascular abnormalities and compared to the conventional approach of using a global AIF. The new methodology produced higher CBF and shorter mean transit time values (compared to the global AIF case) in areas with distorted AIFs, suggesting that the effects of delay/dispersion are minimized. The minimization of these effects using the calculated local AIF should lead to a more accurate quantification of CBF, which can have important implications for diagnosis and management of patients with cerebral ischemia.

  20. Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans.

    PubMed

    Brunt, Vienna E; Howard, Matthew J; Francisco, Michael A; Ely, Brett R; Minson, Christopher T

    2016-09-15

    A recent 30 year prospective study showed that lifelong sauna use reduces cardiovascular-related and all-cause mortality; however, the specific cardiovascular adaptations that cause this chronic protection are currently unknown. We investigated the effects of 8 weeks of repeated hot water immersion ('heat therapy') on various biomarkers of cardiovascular health in young, sedentary humans. We showed that, relative to a sham group which participated in thermoneutral water immersion, heat therapy increased flow-mediated dilatation, reduced arterial stiffness, reduced mean arterial and diastolic blood pressure, and reduced carotid intima media thickness, with changes all on par or greater than what is typically observed in sedentary subjects with exercise training. Our results show for the first time that heat therapy has widespread and robust effects on vascular function, and as such, could be a viable treatment option for improving cardiovascular health in a variety of patient populations, particularly those with limited exercise tolerance and/or capabilities. The majority of cardiovascular diseases are characterized by disorders of the arteries, predominantly caused by endothelial dysfunction and arterial stiffening. Intermittent hot water immersion ('heat therapy') results in elevations in core temperature and changes in cardiovascular haemodynamics, such as cardiac output and vascular shear stress, that are similar to exercise, and thus may provide an alternative means of improving health which could be utilized by patients with low exercise tolerance and/or capabilities. We sought to comprehensively assess the effects of 8 weeks of heat therapy on biomarkers of vascular function in young, sedentary subjects. Twenty young, sedentary subjects were assigned to participate in 8 weeks (4-5 times per week) of heat therapy (n = 10; immersion in a 40.5°C bath sufficient to maintain rectal temperature ≥ 38.5°C for 60 min per session) or thermoneutral water

  1. [Primary culture and functional identification of distal pulmonary artery smooth muscle cells in mice].

    PubMed

    Li, M C; Chen, Y Q; Zhang, C T; Jiang, Q; Lu, W J; Wang, J

    2017-02-12

    Objective: To establish a method of isolation and primary culture of mice distal pulmonary artery smooth muscle cells (PASMCs) and identify the functional properties. Methods: PASMCs were harvested from the distal pulmonary artery (PA) tissue of mice by enzymatic digestion of collagenaseⅠand papain; and the growth characteristics were observed under inverted microscope and identified by Immunofluorescence technique. Effects on the intracellular calcium ion concentration of distal PASMCs were detected by Fura-2-AM fluorescent probe tracer under a fluorescence microscope in Krebs solution containing clopiazonic acid (CPA) and nifedipin (Nif). Results: PASMCs density reached approximately to 80% in a typical valley-peak-like shape after 6 days. Cell α-smooth muscle actin (α-SMA) immunofluorescence identified that 95% of the cultured cells were PASMCs. More than 95% PASMCs responded well to calcium-potassium Krebs solution (potassium ion concentration of 60 mmol/L) and showed a rapid increase in basal [Ca(2+) ](i) after 1 minute's perfusion (Δ[Ca(2+) ](i)>50), which demonstrated that the voltage-dependent calcium channels (VDCC) of distal PASMCs were in good function; after the perfusion of calcium Krebs, calcium-free/calcium-Krebs containing CPA and Nif, distal PASMCs showed two typical peaks, indicated the full function of store-operated calcium channel (SOCC) in distal PASMCs. Conclusion: This experiment successfully established a stable and reliable mice distal PASMCs model and the study of pulmonary vascular diseases could benefit from its higher purity and better functional condition.

  2. Effect of electron radiation on vasomotor function of the left anterior descending coronary artery

    PubMed Central

    Sanzari, Jenine K.; Billings, Paul C.; Wilson, Jolaine M.; Diffenderfer, Eric S.; Arce-Esquivel, Arturo A.; Thorne, Pamela K.; Laughlin, M. H.; Kennedy, Ann R.

    2015-01-01

    The left anterior descending (LAD, interventricular) coronary artery provides the blood supply to the mid-region of the heart and is a major site of vessel stenosis. Changes in LAD function can have major effects on heart function. In this report, we examined the effect of electron simulated solar particle event (eSPE) radiation on LAD function in a porcine animal model. Vasodilatory responses to adenosine diphosphate (ADP; 10−9 – 10−4 M), bradykinin (BK; 10−11 – 10−6 M), and sodium nitroprusside (SNP; 10−10 – 10−4 M) were assessed. The LAD arteries from Control (non-irradiated) and the eSPE (irradiated) animals were isolated and exhibited a similar relaxation response following treatment with either ADP or SNP. In contrast, a significantly reduced relaxation response to BK treatment was observed in the eSPE irradiated group, compared to the control group. These data demonstrate that simulated SPE radiation exposure alters LAD function. PMID:26072960

  3. Effects of dark chocolate and cocoa consumption on endothelial function and arterial stiffness in overweight adults.

    PubMed

    West, Sheila G; McIntyre, Molly D; Piotrowski, Matthew J; Poupin, Nathalie; Miller, Debra L; Preston, Amy G; Wagner, Paul; Groves, Lisa F; Skulas-Ray, Ann C

    2014-02-01

    The consumption of cocoa and dark chocolate is associated with a lower risk of CVD, and improvements in endothelial function may mediate this relationship. Less is known about the effects of cocoa/chocolate on the augmentation index (AI), a measure of vascular stiffness and vascular tone in the peripheral arterioles. We enrolled thirty middle-aged, overweight adults in a randomised, placebo-controlled, 4-week, cross-over study. During the active treatment (cocoa) period, the participants consumed 37 g/d of dark chocolate and a sugar-free cocoa beverage (total cocoa = 22 g/d, total flavanols (TF) = 814 mg/d). Colour-matched controls included a low-flavanol chocolate bar and a cocoa-free beverage with no added sugar (TF = 3 mg/d). Treatments were matched for total fat, saturated fat, carbohydrates and protein. The cocoa treatment significantly increased the basal diameter and peak diameter of the brachial artery by 6% (+2 mm) and basal blood flow volume by 22%. Substantial decreases in the AI, a measure of arterial stiffness, were observed in only women. Flow-mediated dilation and the reactive hyperaemia index remained unchanged. The consumption of cocoa had no effect on fasting blood measures, while the control treatment increased fasting insulin concentration and insulin resistance (P= 0·01). Fasting blood pressure (BP) remained unchanged, although the acute consumption of cocoa increased resting BP by 4 mmHg. In summary, the high-flavanol cocoa and dark chocolate treatment was associated with enhanced vasodilation in both conduit and resistance arteries and was accompanied by significant reductions in arterial stiffness in women.

  4. Molecular and functional significance of Ca2+-activated Cl− channels in pulmonary arterial smooth muscle

    PubMed Central

    Forrest, Abigail S.; Ayon, Ramon J.; Wiwchar, Michael; Angermann, Jeff E.; Pritchard, Harry A. T.; Singer, Cherie A.; Valencik, Maria L.; Britton, Fiona; Greenwood, Iain A.

    2015-01-01

    Abstract Increased peripheral resistance of small distal pulmonary arteries is a hallmark signature of pulmonary hypertension (PH) and is believed to be the consequence of enhanced vasoconstriction to agonists, thickening of the arterial wall due to remodeling, and increased thrombosis. The elevation in arterial tone in PH is attributable, at least in part, to smooth muscle cells of PH patients being more depolarized and displaying higher intracellular Ca2+ levels than cells from normal subjects. It is now clear that downregulation of voltage-dependent K+ channels (e.g., Kv1.5) and increased expression and activity of voltage-dependent (Cav1.2) and voltage-independent (e.g., canonical and vanilloid transient receptor potential [TRPC and TRPV]) Ca2+ channels play an important role in the functional remodeling of pulmonary arteries in PH. This review focuses on an anion-permeable channel that is now considered a novel excitatory mechanism in the systemic and pulmonary circulations. It is permeable to Cl− and is activated by a rise in intracellular Ca2+ concentration (Ca2+-activated Cl− channel, or CaCC). The first section outlines the biophysical and pharmacological properties of the channel and ends with a description of the molecular candidate genes postulated to encode for CaCCs, with particular emphasis on the bestrophin and the newly discovered TMEM16 and anoctamin families of genes. The second section provides a review of the various sources of Ca2+ activating CaCCs, which include stimulation by mobilization from intracellular Ca2+ stores and Ca2+ entry through voltage-dependent and voltage-independent Ca2+ channels. The third and final section summarizes recent findings that suggest a potentially important role for CaCCs and the gene TMEM16A in PH. PMID:26064450

  5. Arterial input function placement effect on computed tomography lung perfusion maps.

    PubMed

    Jimenez-Juan, Laura; Mehrez, Hatem; Dey, Chris; Homampour, Shabnam; Oikonomou, Anastasia; Ursani, Fatima; Paul, Narinder

    2016-02-01

    A critical source of variability in dynamic perfusion computed tomography (DPCT) is the arterial input function (AIF). However, the impact of the AIF location in lung DPCT has not been investigated yet. The purpose of this study is to determine whether the location of the AIF within the central pulmonary arteries influences the accuracy of lung DPCT maps. A total of 54 lung DPCT scans were performed in three pigs using different rates and volumes of iodinated contrast media. Pulmonary blood flow (PBF) perfusion maps were generated using first-pass kinetics in three different AIF locations: the main pulmonary trunk (PT), the right main (RM) and the left main (LM) pulmonary arteries. A total of 162 time density curves (TDCs) and corresponding PBF perfusion maps were generated. Linear regression and Spearman's rank correlation coefficient were used to compare the TDCs. PBF perfusion maps were compared quantitatively by taking twenty six regions of interest throughout the lung parenchyma. Analysis of variance (ANOVA) was used to compare the mean PBF values among the three AIF locations. Two chest radiologists performed qualitative assessment of the perfusion maps using a 3-point scale to determine regions of perfusion mismatch. The linear regression of the TDCs from the RM and LM compared to the PT had a median (range) of 1.01 (0.98-1.03). The Spearman rank correlation between the TDCs was 0.88 (P<0.05). ANOVA analysis of the perfusion maps demonstrated no statistical difference (P>0.05). Qualitative comparison of the perfusion maps resulted in scores of 1 and 2, demonstrating either identical or comparable maps with no significant difference in perfusion defects between the different AIF locations. Accurate PBF perfusion maps can be generated with the AIF located either at the PT, RM or LM pulmonary arteries.

  6. Correlation of coronary artery stenosis evaluation with left heart structure and function by multi-slice computed tomography.

    PubMed

    Song, L N; Cao, A D; Niu, Y J; Liu, N

    2014-08-07

    The aim of this study was to determine the impact of multi-slice computed tomography (MSCT) evaluation of coronary artery stenosis on left heart structure and systolic function. Coronary artery CT angiography was performed in 200 patients diagnosed with coronary heart disease, and then according to the AHA coronary artery 17-segment fractionation method, the Gensini score (GS) was determined for every narrow segment, and one-stop assessment of the correlation between left heart structure and function was performed. After the grouping of GS quartiles from low to high, there were differences between different patients with regard to LVDD, LADD, LVEDV, LVESV, MM, LVEF, and FS, while no difference in SV and CO. GS showed linear negative correlation with LVEF and FS, and linear positive correlation with LVDD, LADD, LVEDV, LVESV, and MM, while no correlation with SV and CO. That is, GS of coronary artery stenosis was negatively correlated with left ventricular systolic function and positively correlated with myocardial mass. The narrower the coronary artery, the worse the cardiac function and the higher the myocardial hypertrophy. Coronary artery stenosis was one of the important causes of the decrease in left ventricular systolic function and cardiac remodeling.

  7. Two functional polymorphisms of ROCK2 enhance arterial stiffening through inhibiting its activity and expression.

    PubMed

    Liao, Yi-Chu; Liu, Ping-Yen; Lin, Hsiu-Fen; Lin, Wen-Yi; Liao, James K; Juo, Suh-Hang H

    2015-02-01

    Derangement of Rho-associated kinases (ROCKs) has been related to coronary artery disease and stroke. ROCK2, rather than ROCK1, plays a predominant role in vascular contractility. The present study aims to test (1) the associations between ROCK2 single nucleotide polymorphisms (SNPs) and arterial stiffness, and (2) the molecular mechanism accounting for their effects. Stiffness parameters including beta (β), elasticity modulus (Ep) and pulse wave velocity (PWV) were obtained by carotid ultrasonography. Seven tagging SNPs of ROCK2 were initially genotyped in 856 subjects and significant SNPs were replicated in another group of 527 subjects. Two SNPs in complete linkage disequilibrium were found to be significantly associated with arterial stiffness. The major alleles of rs978906 (A allele) and rs9808232 (C allele) were associated with stiffer arteries. SNP rs978906 was predicted to influence microRNA(miR)-1183 binding to ROCK2, while rs9808232 causes amino acid substitution. To determine their functional impact, plasmid constructs carrying different alleles of the significant SNPs were created. Compared to rs978906G-allele constructs, cells transfected with rs978906A-allele constructs had higher baseline luciferase activities and were less responsive to miR-1183 changes. Oxidized-low density lipoprotein (Ox-LDL) suppressed miR-1183 levels and increased ROCK2 protein amounts. For rs9808232, cells transfected with C-allele constructs had significantly higher ROCK activities than those with A-allele constructs. Leukocyte ROCK activities were further measured in 52 healthy subjects. The average ROCK activity was highest in human subjects with CC genotype at rs9808232, followed by those with AC and lowest in AA. Taken together, the present study showed that two functional SNPs of ROCK2 increase susceptibility of arterial stiffness in the Chinese population. Non-synonymous SNP rs9808232 influences ROCK2 activity, while 3' UTR SNP rs978906 affects the ROCK2 protein

  8. Histopathological Differences Between the Anterior and Posterior Brain Arteries as a Function of Aging.

    PubMed

    Roth, William; Morgello, Susan; Goldman, James; Mohr, Jay P; Elkind, Mitchell S V; Marshall, Randolph S; Gutierrez, Jose

    2017-03-01

    We tested the hypothesis that posterior brain arteries differ pathologically from anterior brain arteries and that this difference varies with age. Brain large arteries from 194 autopsied individuals (mean age 56±17 years, 63% men, 25% nonwhite, 17% with brain infarcts) were analyzed to obtain the areas of arterial layers and lumen as well as the relative content of elastin, collagen, and amyloid. Visual rating was used to determine the prevalence of atheroma, calcification, vasa vasorum, pattern of intima thickening, and internal elastic lamina gaps. We used multilevel models adjusting for age, sex, ethnicity, vascular risk factors, artery type and location, and multiple comparisons. Of 1362 large artery segments, 5% had vasa vasorum, 5% had calcifications, 15% had concentric intimal thickening, and 11% had atheromas. Posterior brain arteries had thinner walls, less elastin, and more concentric intima thickening than anterior brain arteries. Compared to anterior brain arteries, the basilar artery had higher arterial area encircled by the internal elastic lamina, whereas the vertebral arteries had higher prevalence of elastin loss, concentric intima thickening, and nonatherosclerotic stenosis. In younger individuals, vertebral artery calcifications were more likely than calcification in anterior brain arteries, but this difference attenuated with age. Posterior brain arteries differ pathologically from anterior brain arteries in the degree of wall thickening, elastin loss, and concentric intimal thickening. © 2017 American Heart Association, Inc.

  9. Effects of pentaerythritol tetranitrate on endothelial function in coronary artery disease: results of the PENTA study.

    PubMed

    Schnorbus, Boris; Schiewe, Robert; Ostad, Mir Abolfazl; Medler, Christoph; Wachtlin, Daniel; Wenzel, Philip; Daiber, Andreas; Münzel, Thomas; Warnholtz, Ascan

    2010-02-01

    Pentaerythritol tetranitrate (PETN) differs from other organic nitrates by the lack of tolerance induction and by antioxidative properties. The purpose of this study was to determine the effect of PETN on endothelial function in patients with coronary artery disease (CAD). We hypothesized that the treatment with PETN improves endothelial function in patients with CAD. In a prospective, double-blind study, we randomly assigned 80 patients to treatment for 8 weeks with oral PETN 80 mg t.i.d. (PETN) or placebo (C). The primary endpoint was the absolute change in brachial artery flow-mediated dilation (FMD) from baseline to follow-up. Furthermore, changes in nitroglycerin-mediated dilation (NMD), digital peripheral arterial tonometry (PAT) index, vascular shear stress, mean flow velocity, plasma bilirubin, C-reactive protein (CRP) and thiobarbituric acid reactive substances (TBARS), serum ferritin, and the activity of the PETN bioactivating enzyme aldehyde dehydrogenase-2 (ALDH-2) in peripheral blood mononuclear cells were analyzed. Raw data entry, data monitoring and statistical analysis were performed independently. The treatment groups were comparable regarding demographics, cardiovascular risk and concomitant medication. There was no difference in the change in FMD between the two treatment groups (mean +/- SD: PETN: +1.6 +/- 3.3% vs. C: +1.4 +/- 4.1%; P = 0.7). NMD increased after treatment with PETN and was higher compared with C (PETN: +3.8 +/- 5.5% vs. C: +0.6 +/- 4.2%; P = 0.004). Mean PAT index and ALDH-2 activity remained unchanged. Relative changes in mean flow volume (P = 0.04) and mean flow velocity (P = 0.01) upon ischemia increased in the PETN group versus C. Changes in bilirubin, ferritin, TBARS and CRP did not differ between the groups. We conclude that chronic PETN therapy in patients with CAD may be established for symptomatic treatment without adverse effects on endothelial function and with beneficial effects on the microcirculation.

  10. Highland mountain hiking and coronary artery disease: exercise tolerance and effects on left ventricular function.

    PubMed

    Huonker, M; Schmidt-Trucksäss, A; Sorichter, S; Irmer, M; Dürr, H; Lehmann, M; Keul, J

    1997-12-01

    Physical exercise has become a well-established concept in the secondary prevention of coronary artery disease. We investigated the exercise requirements of extensive highland mountain hiking (8.7 km, 470 m to 1220 m over sea level, average incline 8.5%, mean walking velocity < 3 km x h-1) in 11 regularly exercising male patients with history of MI and stable coronary artery disease (CAD; mean age +/- SD:61.0 +/- 3.9 yr) and 9 age-matched male healthy controls (CO; mean age +/- SD:61.2 +/- 5.0 yr). All subjects underwent continuous ECG monitoring; arterial blood pressure and blood lactate concentrations were measured several times during mountain hiking. Before and after exercise, cardiac dimensions and functions were assessed by two-dimensional echocardiography and Doppler echocardiography. The mean exercise levels for heart rate and blood lactate were compared with the corresponding data of a multistage upright cycle ergometry. Clinical manifestations of coronary insufficiency, left ventricular myocardial dysfunction, or cardiac arrhythmias > Lown IIIb were not observed in any case. No significant differences in left atrial and left ventricular dimensions and no changes in systolic left ventricular function compared with the preexercise values were found after the mountain hike tour. Doppler echocardiography demonstrated significant changes in diastolic left ventricular function in CAD, but not in CO. The peak exercise intensity during mountain hiking was equivalent to a workload of 100-125 W (1.25-1.5 W x kg-1 body weight) in a multistage upright cycle ergometry. Extensive highland mountain hiking may be a low risk alternative within the outpatient rehabilitation program for secondary prevention of CAD for MI patients with a cycle ergometric exercise tolerance > 1.5 W x kg-1 body weight.

  11. Protective effect of beraprost sodium, a new chemically stable prostacyclin analogue, against the deterioration of baroreceptor reflex following transient global cerebral ischaemia in dogs.

    PubMed Central

    Kurihara, J.; Sahara, T.; Kato, H.

    1990-01-01

    1. A possible cerebroprotective effect of a chemically stable prostacyclin analogue, beraprost sodium, was investigated in a canine model of cerebral ischaemia. Cerebral ischaemia was produced by the combined occlusions of the left subclavian and the brachiocephalic arteries with preceding ligations of the intercostal arteries. 2. The decrease in baroreceptor reflex sensitivity (BRS), measured by phenylephrine-induced reflex bradycardia, following 5 min ischaemia was used to assess the cerebroprotective effect. 3. Beraprost (1 microgram kg-1 min-1 i.v., infused for 15 min just before ischaemia) completely prevented the decrease in BRS. Although the lower dose of beraprost (0.1 microgram kg-1 min-1 i.v.) failed to show such a protective effect, its inhibitory effect on ADP-induced platelet aggregation was as potent as that of the higher dose. 4. The extent of decrease in BRS was inversely correlated with the extent of the residual blood flow in the medulla oblongata during ischaemia. Since beraprost did not affect the extent of the residual blood flow during ischaemia, its cerebroprotective effect could not be ascribed to the reduction of the degree of ischaemia by increasing collateral blood flow to the brain. 5. Post-ischaemic reduction of the regional blood flow in the medulla and the cerebral cortex was completely prevented by the higher dose of beraprost. 6. The present study suggests that the cerebroprotective effect of beraprost may be independent of its anti-aggregatory and vasodilator effects. It is possible that the protection may be due to a prostacyclin-like cytoprotective effect through membrane stabilization. PMID:2110014

  12. Improved factor analysis of dynamic PET images to estimate arterial input function and tissue curves

    NASA Astrophysics Data System (ADS)

    Boutchko, Rostyslav; Mitra, Debasis; Pan, Hui; Jagust, William; Gullberg, Grant T.

    2015-03-01

    Factor analysis of dynamic structures (FADS) is a methodology of extracting time-activity curves (TACs) for corresponding different tissue types from noisy dynamic images. The challenges of FADS include long computation time and sensitivity to the initial guess, resulting in convergence to local minima far from the true solution. We propose a method of accelerating and stabilizing FADS application to sequences of dynamic PET images by adding preliminary cluster analysis of the time activity curves for individual voxels. We treat the temporal variation of individual voxel concentrations as a set of time-series and use a partial clustering analysis to identify the types of voxel TACs that are most functionally distinct from each other. These TACs provide a good initial guess for the temporal factors for subsequent FADS processing. Applying this approach to a set of single slices of dynamic 11C-PIB images of the brain allows identification of the arterial input function and two different tissue TACs that are likely to correspond to the specific and non-specific tracer binding-tissue types. These results enable us to perform direct classification of tissues based on their pharmacokinetic properties in dynamic PET without relying on a compartment-based kinetic model, without identification of the reference region, or without using any external methods of estimating the arterial input function, as needed in some techniques.

  13. Progenitor cell release plus exercise to improve functional performance in peripheral artery disease: the PROPEL Study.

    PubMed

    Domanchuk, Kathryn; Ferrucci, Luigi; Guralnik, Jack M; Criqui, Michael H; Tian, Lu; Liu, Kiang; Losordo, Douglas; Stein, James; Green, David; Kibbe, Melina; Zhao, Lihui; Annex, Brian; Perlman, Harris; Lloyd-Jones, Donald; Pearce, William; Taylor, Doris; McDermott, Mary M

    2013-11-01

    Functional impairment, functional decline, and mobility loss are major public health problems in people with lower extremity peripheral artery disease (PAD). Few medical therapies significantly improve walking performance in PAD. We describe methods for the PROgenitor cell release Plus Exercise to improve functionaL performance in PAD (PROPEL) Study, a randomized controlled clinical trial designed to determine whether granulocyte-macrophage colony stimulating factor (GM-CSF) combined with supervised treadmill walking exercise improves six-minute walk distance more than GM-CSF alone, more than supervised treadmill exercise alone, and more than placebo plus attention control in participants with PAD, respectively. PROPEL Study participants are randomized to one of four arms in a 2 by 2 factorial design. The four study arms are GM-CSF plus supervised treadmill exercise, GM-CSF plus attention control, placebo plus supervised exercise therapy, or placebo plus attention control. The primary outcome is change in six-minute walk distance at 12-week follow-up. Secondary outcomes include change in brachial artery flow-mediated dilation (FMD), change in maximal treadmill walking time, and change in circulating CD34+ cells at 12-week follow-up. Outcomes are also measured at six-week and six-month follow-up. Results of the PROPEL Study will have important implications for understanding mechanisms of improving walking performance and preventing mobility loss in the large and growing number of men and women with PAD.

  14. Left Ventricular Diastolic Function Assessment of a Heterogeneous Cohort of Pulmonary Arterial Hypertension Patients

    PubMed Central

    Hernandez-Suarez, Dagmar F.; Lopez Menendez, Francisco R.; Palm, Denada; Lopez-Candales, Angel

    2017-01-01

    Background Pulmonary arterial hypertension (PAH) is known to trigger right ventricular (RV) remodeling that might compromise left ventricular (LV) filling due to inter-ventricular interdependence. In this study, we aimed to examine standard echocardiographic measurements of LV diastolic function in PAH patients. Methods In this retrospective study, we identified clinical as well as complete echocardiographic data from 128 chronic PAH patients to fully assess LV diastolic dysfunction (LVDD) using standard recommended Doppler guidelines. Accordingly, patients were divided into three groups: LVDD 0, LVDD 1 and LVDD 2. Results The mean age of the studied population was 57 ± 14 years with a mean pulmonary artery systolic pressure (PASP) of 55 ± 21 mm Hg. A total of 36% of the study patients had normal LV diastolic function. However, 64% had LVDD with LVDD stage 1 being the most common (48%). In terms of echocardiographic data, significant differences were found among the three LVDD groups in regards to PASP, LV end systolic and diastolic volumes, tricuspid annular plane systolic excursion, right ventricular fractional area change as well as many other tissue Doppler imaging parameters. Finally, just age and PASP were predictors of abnormal LV diastolic function (P < 0.05). Conclusions Impaired relaxation is a common abnormality in PAH patients. Additional studies are warranted to determine whether LVDD alters prognosis or is related to changes in the symptomatic profile of this group of patients. PMID:28270896

  15. Non-invasive imaging in coronary artery disease including anatomical and functional evaluation of ischaemia and viability assessment

    PubMed Central

    Pakkal, M; Raj, V; Mccann, G P

    2011-01-01

    Coronary artery disease has an important impact on the morbidity and mortality statistics and health economics worldwide. Diagnosis of coronary artery disease is important in risk stratification and guides further management. Invasive coronary angiography is the traditional method of imaging the coronary arteries and remains the gold standard. It detects luminal stenosis but provides little information about the vessel wall or plaques. Besides, not all anatomical lesions are functionally significant. This has lent itself to a wide variety of imaging techniques to identify and assess a flow-limiting stenosis. The approach to diagnosis of coronary artery disease is broadly based on anatomical and functional imaging. Coronary CT and MRI of coronary arteries provide an anatomical assessment of coronary stenosis. Coronary calcium score and coronary CT assess subclinical atherosclerosis by assessing the atherosclerotic plaque burden. The haemodynamic significance of a coronary artery stenosis can be assessed by stress radioisotope studies, stress echocardiography and stress MRI. The more recent literature also focuses on plaque assessment and identification of plaques that are likely to give rise to an acute coronary syndrome. There is an explosion of literature on the merits and limitations of the different imaging modalities. This review article will provide an overview of all the imaging modalities in the diagnosis of coronary artery disease. PMID:22723535

  16. Arterial Structure and Function in Women and Men Following Long Duration Bed Rest

    NASA Technical Reports Server (NTRS)

    Lee, Stuart M. C.; Stenger, Michael B.; Martin, David S.; Platts, Steven H.

    2008-01-01

    Orthostatic intolerance is a well-recognized consequence of space flight and bed rest (BR), with a greater incidence reported in women. We hypothesized that leg, but not arm, arterial structure and function would be altered following prolonged BR, as a model of space flight, and that women would be more susceptible to BR-induced deconditioning than men. METHODS: Ten volunteers (5 males, 5 females) completed 90 d of 6 head-down BR. Subjects participated in tests of brachial (BA) and anterior tibial (AT) artery endothelium-dependent (flow mediated dilation [FMD] following 5-7 min of arterial occlusion) and endothelium-independent (0.4 mg sublingual nitroglycerin [SN]) vasodilation before BR (PRE) and on days 7 (BR7), 21 (BR21), and 90 (BR90) of BR. Vessel diameter and intimal medial thickness (IMT) were measured by ultrasound. IMT, baseline diameter, and percent change in diameter from baseline during FMD and SN tests were compared across BR and between genders using repeated measures two-way ANOVA with Bonferroni post-hoc tests in which PRE and women were control conditions. RESULTS: Baseline vessel diameter was lower in women than in men in both the BA (p=0.005) and AT (p=0.01) across all days. Baseline AT diameter decreased during BR (p=0.01) and tended to be more profound in women (interaction, p=0.06). AT diameter was reduced in women at BR21 and BR90 (p<0.01) but not in men. In contrast, there was no BR effect on baseline BA diameter. IMT also decreased in the AT (p<0.001) but not in the BA during BR; AT IMT was reduced by BR21 (p<0.05). As a group, there was no effect of BR on AT FMD, BA FMD, and AT SN-dilation, although BA SN-dilation was significantly reduced on BR21 (p=0.01). Across all BR days, women exhibited higher AT FMD (p=0.03), BA FMD (p=0.02), and BA SN-dilation (p=0.01) and tended to demonstrate greater AT SN-dilation (p=0.11). CONCLUSIONS: These preliminary results suggest that arterial remodeling occurs during BR in the leg (decreased diameter

  17. Arterial Structure and Function in Women and Men Following Long Duration Bed Rest

    NASA Technical Reports Server (NTRS)

    Lee, Stuart M. C.; Stenger, Michael B.; Martin, David S.; Platts, Steven H.

    2008-01-01

    Orthostatic intolerance is a well-recognized consequence of space flight and bed rest (BR), with a greater incidence reported in women. We hypothesized that leg, but not arm, arterial structure and function would be altered following prolonged BR, as a model of space flight, and that women would be more susceptible to BR-induced deconditioning than men. METHODS: Ten volunteers (5 males, 5 females) completed 90 d of 6 head-down BR. Subjects participated in tests of brachial (BA) and anterior tibial (AT) artery endothelium-dependent (flow mediated dilation [FMD] following 5-7 min of arterial occlusion) and endothelium-independent (0.4 mg sublingual nitroglycerin [SN]) vasodilation before BR (PRE) and on days 7 (BR7), 21 (BR21), and 90 (BR90) of BR. Vessel diameter and intimal medial thickness (IMT) were measured by ultrasound. IMT, baseline diameter, and percent change in diameter from baseline during FMD and SN tests were compared across BR and between genders using repeated measures two-way ANOVA with Bonferroni post-hoc tests in which PRE and women were control conditions. RESULTS: Baseline vessel diameter was lower in women than in men in both the BA (p=0.005) and AT (p=0.01) across all days. Baseline AT diameter decreased during BR (p=0.01) and tended to be more profound in women (interaction, p=0.06). AT diameter was reduced in women at BR21 and BR90 (p<0.01) but not in men. In contrast, there was no BR effect on baseline BA diameter. IMT also decreased in the AT (p<0.001) but not in the BA during BR; AT IMT was reduced by BR21 (p<0.05). As a group, there was no effect of BR on AT FMD, BA FMD, and AT SN-dilation, although BA SN-dilation was significantly reduced on BR21 (p=0.01). Across all BR days, women exhibited higher AT FMD (p=0.03), BA FMD (p=0.02), and BA SN-dilation (p=0.01) and tended to demonstrate greater AT SN-dilation (p=0.11). CONCLUSIONS: These preliminary results suggest that arterial remodeling occurs during BR in the leg (decreased diameter

  18. Hypertension during Pregnancy is Associated with Coronary Artery Calcium Independent of Renal Function

    PubMed Central

    Cassidy-Bushrow, Andrea E.; Bielak, Lawrence F.; Rule, Andrew D.; Sheedy, Patrick F.; Turner, Stephen T.; Garovic, Vesna D.

    2009-01-01

    Abstract Background Hypertension during pregnancy (HDP) increases the risk of future coronary heart disease (CHD), but it is unknown whether this association is mediated by renal injury. Reduced renal function is both a complication of HDP and a risk factor for CHD. Methods Logistic regression models were fit to examine the association between a history of HDP and the presence and extent of coronary artery calcification (CAC), a measure of subclinical coronary artery atherosclerosis, in 498 women from the Epidemiology of Coronary Artery Calcification Study (mean age 63.3 ± 9.3 years). Results Fifty-two (10.4%) women reported a history of HDP. After adjusting for age at time of study participation, HDP was associated with increased serum creatinine later in life (p = 0.014). HDP was positively associated with the presence of CAC after adjusting for age at time of study participation (OR = 2.7, 95% CI 1.4-5.4). This association was slightly attenuated with adjustment for body size and blood pressure (OR = 2.4, 95% CI 1.2-4.9) but was not further attenuated with adjustment for serum creatinine and urinary albumin/creatinine ratio (OR = 2.6, 95% CI 1.3-5.3). Results were similar for CAC extent. Conclusions HDP may increase a woman's risk of future CHD beyond traditional risk factors and renal function. Women with a history of HDP should be monitored for potential increased risk of CHD as they age. PMID:19785565

  19. Exercise training improves conduit vessel function in patients with coronary artery disease.

    PubMed

    Walsh, Jennifer H; Bilsborough, William; Maiorana, Andrew; Best, Matthew; O'Driscoll, Gerard J; Taylor, Roger R; Green, Daniel J

    2003-07-01

    It is well established that endothelial dysfunction is present in coronary artery disease (CAD), although few studies have determined the effect of training on peripheral conduit vessel function in patients with CAD. A randomized, crossover design determined the effect of 8 wk of predominantly lower limb, combined aerobic and resistance training, in 10 patients with treated CAD. Endothelium-dependent dilation of the brachial artery was determined, by using high-resolution vascular ultrasonography, from flow-mediated vasodilation (FMD) after ischemia. Endothelium-independent vasodilation was measured after administration of glyceryl trinitrate (GTN). Baseline function was compared with that of 10 control subjects. Compared with matched healthy control subjects, FMD and GTN responses were significantly impaired in the untrained CAD patients [3.0 +/- 0.8 (SE) vs. 5.8 +/- 0.8% and 14.5 +/- 1.9 vs. 20.4 +/- 1.5%, respectively; both P < 0.05]. Training significantly improved FMD in the CAD patients (from 3.0 +/- 0.8 to 5.7 +/- 1.1%; P < 0.05) but not responsiveness to GTN (14.5 +/- 1.9 vs. 12.1 +/- 1.4%; P = not significant). Exercise training improves endothelium-dependent conduit vessel dilation in subjects with CAD, and the effect, evident in the brachial artery, appears to be generalized rather than limited to vessels of exercising muscle beds. These results provide evidence for the benefit of exercise training, as an adjunct to routine therapy, in patients with a history of CAD.

  20. Transmural differences in myocardial function and metabolism during direct left ventricular to coronary artery sourcing.

    PubMed

    de Zeeuw, Sandra; Borst, Cornelius; Verlaan, Cees W J; Gründeman, Paul F

    2005-07-01

    We investigated the hypothesis that in the absence of collateral circulation, a left ventricle-coronary artery (LV-CA) bypass will maintain normal LV wall function and metabolism transmurally, both at rest and during stress, when the left anterior descending coronary artery (LAD) is acutely occluded proximally. In 18 anesthetized pigs (74 +/- 7 kg, mean +/- standard deviation), a covered stent was placed transmurally in the lateral wall of the beating LV and connected to the proximal LAD via an arterial graft. Subepicardial and subendocardial segmental shortening as well as interstitial lactate and glucose concentrations were measured regionally by sonomicrometry and microdialysis, respectively. When the LAD was occluded proximally, direct left ventricular sourcing decreased the net LAD flow to 64 +/- 25% of the native flow (n = 18, all animals). In the subepicardium, systolic shortening (SS) decreased to 87 +/- 18% of baseline (p = 0.124), with the appearance of minor postsystolic shortening (PSS), and minor changes in interstitial lactate and glucose levels. In the subendocardium, in contrast, SS decreased to 54 +/- 20% (p = 0.001). Marked PSS concurred with a sixfold increase in lactate (p = 0.008), and a 65 +/- 31% decrease in glucose (p = 0.003), indicating subendocardial anaerobic metabolism. Stress induced by infusion of dobutamine increased lactate and decreased glucose concentration in the subepicardium to subendocardial levels, indicating transmural anaerobic metabolism. In the anesthetized pig, direct sourcing by a LV-CA bypass distal to an acute coronary occlusion resulted in a 36% decrease in net forward coronary flow, subendocardial anaerobic metabolism, and loss of subendocardial contractile function at rest. These adverse effects extended into the subepicardium when the heart was stressed.

  1. The Effect of Endovascular Revascularization of Common Iliac Artery Occlusions on Erectile Function

    SciTech Connect

    Gur, Serkan; Ozkan, Ugur; Onder, Hakan; Tekbas, Gueven; Oguzkurt, Levent

    2013-02-15

    To determine the incidence of erectile dysfunction in patients with common iliac artery (CIA) occlusive disease and the effect of revascularization on erectile function using the sexual health inventory for males (SHIM) questionnaire. All patients (35 men; mean age 57 {+-} 5 years; range 42-67 years) were asked to recall their sexual function before and 1 month after iliac recanalization. Univariate and multivariate analyses were performed to determine variables effecting improvement of impotence. The incidence of impotence in patients with CIA occlusion was 74% (26 of 35) preoperatively. Overall 16 (46%) of 35 patients reported improved erectile function after iliac recanalization. The rate of improvement of impotence was 61.5% (16 of 26 impotent patients). Sixteen patients (46%), including seven with normal erectile function before the procedure, had no change. Three patients (8%) reported deterioration of their sexual function, two of whom (6%) had normal erectile function before the procedure. The median SHIM score increased from 14 (range 4-25) before the procedure to 20 (range 1-25) after the procedure (P = 0.005). The type of recanalization, the age of the patients, and the length of occlusion were related to erectile function improvement in univariate analysis. However, these factors were not independent factors for improvement of erectile dysfunction in multivariate analysis (P > 0.05). Endovascular recanalization of CIA occlusions clearly improves sexual function. More than half of the patients with erectile dysfunction who underwent endovascular recanalization of the CIA experienced improvement.

  2. Impaired motor activity and motor learning function in rat with middle cerebral artery occlusion.

    PubMed

    Ding, Yuchuan; Zhou, Yandong; Lai, Qin; Li, Jie; Park, Hun; Diaz, Fernando G

    2002-04-15

    The poor quality of life after a stroke is largely attributed to deficits in cognitive-motor functioning. The goals of this study were to detect if damaged motor learning function were attributed to motor deficits in rats following a transient middle cerebral artery (MCA) occlusion. Stroke was induced by a 2-h occlusion of the MCA using an intraluminal filament. Motor functions were evaluated from 5 up to 28 days after reperfusion in ischemic and control rats. Motor function was detected by a series of motor tests (runway traversing and beam balancing, as well as foot fault placing, parallel bar crossing, rope and ladder climbing), and motor learning behavior was determined by analyzing the rate of improvement of impaired function during performance of the motor tasks. Significant (P<0.001) motor deficits were detected in the stroke group (n=10) while performing motor tasks that involve extensive coordination, in comparison to the controls (n=12). Although motor behavior was improved with repeated behavior testing, unparalleled rate of improvement of motor performance on rope and ladder climbing tests was found between the two groups, suggesting an impaired motor learning function. Brain tissue damage was detected in the ischemic animals 28 days after surgery, demonstrated by 40% infarct volume of contralateral hemisphere. Both motor learning and motor function were impaired in ischemic rats. The motor tests used in this study are sensitive, semi-quantitative, and reproducible measurements of functional impairment in rats following an ischemic stroke.

  3. Can selective arterial clamping with fluorescence imaging preserve kidney function during robotic partial nephrectomy?

    PubMed

    McClintock, Tyler R; Bjurlin, Marc A; Wysock, James S; Borofsky, Michael S; Marien, Tracy P; Okoro, Chinonyerem; Stifelman, Michael D

    2014-08-01

    To compare renal functional outcomes in robotic partial nephrectomy (RPN) with selective arterial clamping guided by near-infrared fluorescence (NIRF) imaging to a matched cohort of patients who underwent RPN without selective arterial clamping and NIRF imaging. From April 2011 to December 2012, NIRF imaging-enhanced RPN with selective clamping was used in 42 cases. Functional outcomes of successful cases were compared with a cohort of patients, matched by tumor size, preoperative estimated glomerular filtration rate (eGFR), functional kidney status, age, sex, body mass index, and American Society of Anesthesiologists score, who underwent RPN without selective clamping and NIRF imaging. In matched-pair analysis, selective clamping with NIRF was associated with superior kidney function at discharge, as demonstrated by postoperative eGFR (78.2 vs 68.5 mL/min/1.73 m(2); P = .04), absolute reduction of eGFR (-2.5 vs -14.0 mL/min/1.73 m(2); P <.01), and percent change in eGFR (-1.9% vs -16.8%; P <.01). Similar trends were noted at 3 month follow-up, but these differences became nonsignificant (P[eGFR] = .07; P[absolute reduction of eGFR] = .10; and P[percent change in eGFR] = .07). In the selective clamping group, a total of 4 perioperative complications occurred in 3 patients, all of which were Clavien grade I-III. Use of NIRF imaging was associated with improved short-term renal functional outcomes when compared with RPN without selective arterial clamping and NIRF imaging. With this effect attenuated at later follow-up, randomized prospective studies and long-term assessment of kidney-specific functional outcomes are needed to further assess the benefits of this technology. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Integrative functional genomics identifies regulatory mechanisms at coronary artery disease loci

    PubMed Central

    Miller, Clint L.; Pjanic, Milos; Wang, Ting; Nguyen, Trieu; Cohain, Ariella; Lee, Jonathan D.; Perisic, Ljubica; Hedin, Ulf; Kundu, Ramendra K.; Majmudar, Deshna; Kim, Juyong B.; Wang, Oliver; Betsholtz, Christer; Ruusalepp, Arno; Franzén, Oscar; Assimes, Themistocles L.; Montgomery, Stephen B.; Schadt, Eric E.; Björkegren, Johan L.M.; Quertermous, Thomas

    2016-01-01

    Coronary artery disease (CAD) is the leading cause of mortality and morbidity, driven by both genetic and environmental risk factors. Meta-analyses of genome-wide association studies have identified >150 loci associated with CAD and myocardial infarction susceptibility in humans. A majority of these variants reside in non-coding regions and are co-inherited with hundreds of candidate regulatory variants, presenting a challenge to elucidate their functions. Herein, we use integrative genomic, epigenomic and transcriptomic profiling of perturbed human coronary artery smooth muscle cells and tissues to begin to identify causal regulatory variation and mechanisms responsible for CAD associations. Using these genome-wide maps, we prioritize 64 candidate variants and perform allele-specific binding and expression analyses at seven top candidate loci: 9p21.3, SMAD3, PDGFD, IL6R, BMP1, CCDC97/TGFB1 and LMOD1. We validate our findings in expression quantitative trait loci cohorts, which together reveal new links between CAD associations and regulatory function in the appropriate disease context. PMID:27386823

  5. Stem cells cardiac patch from decellularized umbilical artery improved heart function after myocardium infarction.

    PubMed

    Li, Na; Huang, RanRan; Zhang, XiaoXia; Xin, Yi; Li, Jia; Huang, YiMin; Cui, Wei; Stoltz, Jean-Francois; Zhou, YuJie; Kong, QingYu

    2017-01-01

    The construction of the high biocompatible biomaterials pretreated with MSC offers a promising strategy to improve the effects of stem cell therapy for the myocardial infarction (MI). However, assembling vascularized three-dimensional (3-D) myocardial tissues remains an enormous challenge. In this study, we optimized the decellularization protocol with the umbilical artery to construct microporous 3-D scaffold which is suitable for the stem cells (SC) proliferation. The SD rats underwent proximal left coronary ligation and a 5-mm diameter microporous SC patch was implanted directly on the infarct area (SC patch group). The LV contractile function, regional myocardial wall compliance, and tissue histology were assessed 4 weeks after patch implantation. The MSC patch integrated to the local heart tissue and the neo-vessels have been observed in the MSC patch. The vessels in the MSC patch were positive for the CD31 (marker for the mature endothelial cells). The left ventricle wall was thicker in the MSC patch group than the control group (p<0.05 vs. empty patch group). And the LVEF has been improved in the MSC patch group than empty patch group (59±6.7% vs. 31±4.5%, p<0.05). Our results showed that the implantation of the MSC patch improved cardiac contractile function in heart infarction rat model. The construction of artificial tissue from the decellularized umbilical artery and the MSC may open a promising perspective for the tissue therapy for MI.

  6. [A brief history of the baroreceptor reflex: from Claude Bernard to Arthur C. Guyton. Illustrated with some classical experiments].

    PubMed

    Estañol, Bruno; Porras-Betancourt, Manuel; Padilla-Leyva, Miguel Ángel; Sentíes-Madrid, Horacio

    2011-01-01

    The baroreceptor reflex is poorly known by most physicians even though is fundamental in stabilizing the blood pressure on a beat to beat basis and is crucial for survival. Its fascinating history is briefly reviewed in this article. In 1852 Claude Bernard discovered that the sympathetic nerves of the neck innervate the blood vessels of the skin of the rabbit. Edgar Douglas Adrian in 1932 demonstrated that the sympathetic nerves that innervate the blood vessels discharge spontaneously at a rate of 4-6 per second and thus discovered the physiological basis of the vasomotor tone. In the XIX century Ludwig Traube and Karl Constantine Ewald Hering discovered that blood pressure fluctuates synchronously with respiratory movements and Sigmund Mayer observed that there are also slow non respiratory fluctuations of blood pressure. In 1921 Heinrich Ewald Hering found that high pressure baroreceptors are located in the carotid sinuses and demonstrated that the stimulation of the afferent nerve that innervates it induces bradycardia and hypotension. These studies were further advanced by Corneille Heymans who won the Nobel Prize for these studies in 1938. Later Cowley and Guyton produced sino-aortic denervation in dogs and thereby could demonstrate the fundamental importance of the baroreceptor reflex in the stabilization of blood pressure.

  7. The effect of plasma osmolality and baroreceptor loading status on postexercise heat loss responses.

    PubMed

    Paull, Gabrielle; Dervis, Sheila; Barrera-Ramirez, Juliana; McGinn, Ryan; Haqani, Baies; Flouris, Andreas D; Kenny, Glen P

    2016-03-15

    We examined the separate and combined effects of plasma osmolality and baroreceptor loading status on postexercise heat loss responses. Nine young males completed a 45-min treadmill exercise protocol at 58 ± 2% V̇o2 peak, followed by a 60-min recovery. On separate days, participants received 0.9% NaCl (ISO), 3.0% NaCl (HYP), or no infusion (natural recovery) throughout exercise. In two additional sessions (no infusion), lower-body negative (LBNP) or positive (LBPP) pressure was applied throughout the final 45 min of recovery. Local sweat rate (LSR; ventilated capsule: chest, forearm, upper back, forehead) and skin blood flow (SkBF; laser-Doppler flowmetry: forearm, upper back) were continuously measured. During HYP, upper back LSR was attenuated from end-exercise to 10 min of recovery by ∼0.35 ± 0.10 mg·min(-1)·cm(-2) and during the last 20 min of recovery by ∼0.13 ± 0.03 mg·min(-1)·cm(-2), while chest LSR was lower by 0.18 ± 0.06 mg·min(-1)·cm(-2) at 50 min of recovery compared with natural recovery (all P < 0.05). Forearm and forehead LSRs were not affected by plasma hyperosmolality during HYP (all P > 0.28), which suggests regional differences in the osmotic modulation of postexercise LSR. Furthermore, LBPP application attenuated LSR by ∼0.07-0.28 mg·min(-1)·cm(-2) during the last 30 min of recovery at all sites except the forehead compared with natural recovery (all P < 0.05). Relative to natural recovery, forearm and upper back SkBF were elevated during LBPP, ISO, and HYP by ∼6-10% by the end of recovery (all P < 0.05). We conclude that 1) hyperosmolality attenuates postexercise sweating heterogeneously among skin regions, and 2) baroreceptor loading modulates postexercise SkBF independently of changes in plasma osmolality without regional differences.

  8. [Cognitive functions in patients with stenosing lesion of brachio-cephalic arteries].

    PubMed

    Gavrilova, O V; Buklina, S B; Stakhovskaia, L V; Usachev, D Iu; Lukshin, V A; Beliaev, A Iu; Akhmetov, V V; Skvortsova, V I

    2011-01-01

    Authors studied cognitive functions in 97 patients with different clinical presentations, lateralization and number of stenotic brachio-cephalic vessels. The Luria's syndrome neuropsychological analysis distinctly revealed the topics of cognitive deficits. Wechsler verbal memory tests, the Stroop test (words-figures), the Schulte test were administered as well. Disturbances of high psychic functions were found in 97.9% of patients. The bilateral pathology of lobe regions was noted most often. The dysfunction of parietal and temporal lobes was mainly unilateral and was linked with the side of stenosing process. Disturbances of neurodynamic parameters of mental activity were correlated with the age (higher frequency in patients older than 50 years), a side of stenosis and/or lesion of stroke, bilateral lesions of carotid arteries. The results allow a more precise assessment of clinical significance of carotid stenosis in the development of cognitive dysfunction that may assist in recommendation of surgical treatment.

  9. Pulmonary artery wave propagation and reservoir function in conscious man: impact of pulmonary vascular disease, respiration and dynamic stress tests.

    PubMed

    Su, Junjing; Manisty, Charlotte; Simonsen, Ulf; Howard, Luke S; Parker, Kim H; Hughes, Alun D

    2017-08-17

    Wave travel plays an important role in cardiovascular physiology. However, many aspects of pulmonary arterial wave behaviour remain unclear. Wave intensity and reservoir-excess pressure analyses were applied in the pulmonary artery in subjects with and without pulmonary hypertension during spontaneous respiration and dynamic stress tests. Arterial wave energy decreased during expiration and Valsalva manoeuvre due to decreased ventricular preload. Wave energy also decreased during handgrip exercise due to increased heart rate. In pulmonary hypertension patients, the asymptotic pressure at which the microvascular flow ceases, the reservoir pressure related to arterial compliance and the excess pressure caused by waves increased. The reservoir and excess pressures decreased during Valsalva manoeuvre but remained unchanged during handgrip exercise. This study provides insights into the influence of pulmonary vascular disease, spontaneous respiration and dynamic stress tests on pulmonary artery wave propagation and reservoir function. Detailed haemodynamic analysis may provide novel insights into the pulmonary circulation. Therefore, wave intensity and reservoir-excess pressure analyses were applied in the pulmonary artery to characterize changes in wave propagation and reservoir function during spontaneous respiration and dynamic stress tests. Right heart catheterization was performed using a pressure and Doppler flow sensor tipped guidewire to obtain simultaneous pressure and flow velocity measurements in the pulmonary artery in control subjects and patients with pulmonary arterial hypertension (PAH) at rest. In controls, recordings were also obtained during Valsalva manoeuvre and handgrip exercise. The asymptotic pressure at which the flow through the microcirculation ceases, the reservoir pressure related to arterial compliance and the excess pressure caused by arterial waves increased in PAH patients compared to controls. The systolic and diastolic rate constants

  10. Measurement of brachial artery endothelial function using a standard blood pressure cuff

    PubMed Central

    Maltz, Jonathan S; Tison, Geoffrey H; Alley, Hugh F; Budinger, Thomas F; Owens, Christopher D; Olgin, Jeffrey

    2016-01-01

    The integrity of endothelial function in major arteries (EFMA) is a powerful independent predictor of heart attack and stroke. Existing ultrasound-based non-invasive assessment methods are technically challenging and suitable only for laboratory settings. EFMA, like blood pressure (BP), is both acutely and chronically affected by factors such as lifestyle and medication. Consequently, lab-based measurements cannot fully gauge the effects of medical interventions on EFMA. EFMA and BP have, arguably, comparable (but complementary) value in the assessment of cardiovascular health. Widespread deployment of EFMA assessment is thus a desirable clinical goal. To this end, we propose a device based on modifying the measurement protocol of a standard electronic sphygmomanometer. Methods The protocol involves inflating the cuff to sub-diastolic levels to enable recording of the pulse waveform before and after vasodilatory stimulus. The mechanical unloading of the arterial wall provided by the cuff amplifies the distension that occurs with each pulse, which is measured as a pressure variation in the cuff. We show that the height of the rising edge of each pulse is proportional to the change in lumen area between diastole and systole. This allows the effect of vasodilatory stimuli on the artery to be measured with high sensitivity. We compare the proposed cuff flow-mediated dilation (cFMD) method to ultrasound FMD (uFMD). Results We find significant correlation (r=0.55, p = 0.003, N=27) between cFMD- and uFMD-based metrics obtained when the release of a 5-minute cuff occlusion is employed to induce endothelial stimulus via reactive hyperemia. cFMD is approximately proportional to the square of uFMD, representing a typical increase in sensitivity to vasodilation of 300–600%. Conclusion This study illustrates the potential for an individual to conveniently measure his/her EFMA by using a low-cost reprogrammed home sphygmomanometer. PMID:26393958

  11. Automated detection of arterial input function in DSC perfusion MRI in a stroke rat model

    NASA Astrophysics Data System (ADS)

    Yeh, M.-Y.; Lee, T.-H.; Yang, S.-T.; Kuo, H.-H.; Chyi, T.-K.; Liu, H.-L.

    2009-05-01

    Quantitative cerebral blood flow (CBF) estimation requires deconvolution of the tissue concentration time curves with an arterial input function (AIF). However, image-based determination of AIF in rodent is challenged due to limited spatial resolution. We evaluated the feasibility of quantitative analysis using automated AIF detection and compared the results with commonly applied semi-quantitative analysis. Permanent occlusion of bilateral or unilateral common carotid artery was used to induce cerebral ischemia in rats. The image using dynamic susceptibility contrast method was performed on a 3-T magnetic resonance scanner with a spin-echo echo-planar-image sequence (TR/TE = 700/80 ms, FOV = 41 mm, matrix = 64, 3 slices, SW = 2 mm), starting from 7 s prior to contrast injection (1.2 ml/kg) at four different time points. For quantitative analysis, CBF was calculated by the AIF which was obtained from 10 voxels with greatest contrast enhancement after deconvolution. For semi-quantitative analysis, relative CBF was estimated by the integral divided by the first moment of the relaxivity time curves. We observed if the AIFs obtained in the three different ROIs (whole brain, hemisphere without lesion and hemisphere with lesion) were similar, the CBF ratios (lesion/normal) between quantitative and semi-quantitative analyses might have a similar trend at different operative time points. If the AIFs were different, the CBF ratios might be different. We concluded that using local maximum one can define proper AIF without knowing the anatomical location of arteries in a stroke rat model.

  12. Brachial artery retrograde flow increases with age: relationship to physical function

    PubMed Central

    Credeur, Daniel P.; Dobrosielski, Devon A.; Arce-Esquivel, Arturo A.; Welsch, Michael A.

    2010-01-01

    The purpose of this study was to examine the flow velocity pattern of the brachial artery and to determine its relationship to measures of physical function. Subjects from the Louisiana Healthy Aging Study (n = 95; age = 84 ± 10 years) were evaluated. Brachial artery flow velocities and dimensions were measured using high-resolution ultrasonography. The continuous scale of physical function and performance test (CS-PFP10) was used to assess physical function. This test is based on the performance of 11 activities of daily living. Total CS-PFP10 score was 39.51 ± 21.21 U. Mean antegrade and retrograde velocities at rest were 14.2 ± 4.7 and 3.6 ± 2.2 cm/s, respectively. Ante-/retrograde ratio was 5.5 ± 4.6. Brachial artery diameter was 4.3 ± 0.7 mm. Pulse pressure and vascular conductance were 66 ± 18 mmHg, and 0.9 ± 0.5 ml/min/mmHg, respectively. Vascular conductance (r = −0.34), ante-/retrograde ratio (r = −0.42) and CS-PFP10 (r = −0.65) were inversely and retrograde velocity (r = 0.40) and pulse pressure (r = 0.36), were directly associated with age. Retrograde velocity was inversely related to vascular conductance (r = −0.27) and CS-PFP10 total score (r = −0.45). A MANOVA revealed that those with the higher CS-PFP10 scores had a lower retrograde velocity (P = 0.0001), but this association was, in part, age-dependent. Among nonagenarians (n = 52), those in the lower tertiles of the CS-PFP10 scores had significantly higher retrograde velocities compared to those in the higher tertiles (P = 0.035). These data indicate an increase in brachial retrograde velocity with age. These hemodynamic changes are related to a decline in physical function. PMID:19565260

  13. Breast feeding in infancy and arterial endothelial function later in life. The Cardiovascular Risk in Young Finns Study.

    PubMed

    Järvisalo, M J; Hutri-Kähönen, N; Juonala, M; Mikkilä, V; Räsänen, L; Lehtimäki, T; Viikari, J; Raitakari, O T

    2009-05-01

    Breast feeding in infancy may be associated with reduced cardiovascular morbidity in adulthood. We examined the association between breast feeding in infancy and arterial function and structure in adulthood in a population-based cohort of Finnish adults. Noninvasive ultrasound was used to measure brachial artery flow-mediated dilatation (FMD), carotid artery intima-media thickness (IMT) and carotid artery compliance (CAC) in 1667 young adults participating in the Cardiovascular Risk in Young Finns Study with data on early nutrition. Maximal FMD was higher in breast-fed men compared to formula-fed men (7.2+/-4.0 vs 5.9+/-3.4%, P=0.029) while no differences were seen between breast-fed and formula-fed women (8.9+/-4.5 vs 8.8+/-5.0%, P=0.84). In men, the multivariable correlates of FMD included the group variable for breast feeding (P=0.014), birth weight (P=0.043), waist circumference (P<0.001) and baseline brachial artery diameter (P<0.001). In women, the multivariable correlates of FMD were birth weight (P=0.02), waist circumference (P<0.001) and brachial artery baseline diameter (P<0.001). Breast feeding was not significantly associated with IMT or CAC in multivariable models. Adult men who have been breast fed have better brachial endothelial function compared to men who have been formula fed.

  14. Regional myocardial functional and electrophysiological alterations after brief coronary artery occlusion in conscious dogs.

    PubMed Central

    Heyndrickx, G R; Millard, R W; McRitchie, R J; Maroko, P R; Vatner, S F

    1975-01-01

    The time relationship for recovery of mechanical function, the intramyocardial electrogram and coronary flow after brief periods of regional myocardial ischemia, was studied in conscious dogs. Total left vemtricular (LV) function was assessed with measurements of LV systolic and diastolic pressures, rate of change of LV pressure (dP/dt), and dP/dt/P. Regional LV function was assessed with measurements of regional segment length and velocity of shortening. An implanted hydraulic occluder on either the left anterior descending or circumflex coronary artery was inflated for 5- and 15-min periods on separate days. A 5-min occlusion depressed overall LV function transiently, but just before release of occlusion overall function had nearly returned to control. At this time regional function in the ischemic zone was still depressed to the point of absent shorteining or paradoxical motion during systole and was associated with marked ST segment elevation (+ 10 +/- 2.2 mV) at the site where function was measured. With release of occlusion and reperfusion the intramyocardial electrogram returned to normal within 1 min, and reactive hyperemia subsided by 5-10 min. In contrast to the rapid return to preocclusion levels for coronary flow and the electrogram, regional mechanical function remained depressed for over 3 h. A 15-min coronary occlusion resulted in an even more prolonged (greater than 6 h) derangement of function in the ischemic zone. Thus, brief periods of coronary occlusion result in prolonged impairement of regional myocardial function which could not have been predicted from the rapid return of the electrogram and coronary flow. These observations indicate that brief interruptions of coronary flow result either in a prolonged period of local ischemia or that alterations of mechanical induced by ischemia far outlast the repayment of the oxygen debt. PMID:1159098

  15. Is there an association between altered baroreceptor sensitivity and obstructive sleep apnoea in the healthy elderly?

    PubMed

    Sforza, Emilia; Martin, Magali Saint; Barthélémy, Jean Claude; Roche, Frédéric

    2016-07-01

    Obstructive sleep apnoea (OSA) is associated with a rise in cardiovascular risk in which increased sympathetic activity and depressed baroreceptor reflex sensitivity (BRS) have been proposed. We examined this association in a sample of healthy elderly subjects with unrecognised OSA. 801 healthy elderly (aged ≥65 years) subjects undergoing clinical, respiratory polygraphy and vascular assessment were examined. According to the apnoea-hypopnoea index (AHI), the subjects were stratified into no OSA, mild-moderate OSA and severe OSA cases. OSA was present in 62% of the sample, 62% being mild-moderate and 38% severe. No differences were found for BRS value according to sex and OSA severity. 54% of the group had normal BRS value, 36% mild impairment and 10% severe dysfunction. BRS was negatively associated with body mass index (p=0.006), 24-h systolic (p=0.001) and diastolic pressure (p=0.001), and oxygen desaturation index (ODI) (p=0.03). Regression analyses revealed that subjects with lower BRS were those with hypertension (OR 0.41, 95% CI 0.24-0.81; p=0.002) and overweight (OR 0.42, 95% CI 0.25-0.81; p=0.008), without the effect of AHI and ODI. In the healthy elderly, the presence of a severe BRS dysfunction affects a small amount of severe cases without effect on snorers and mild OSA. Hypertension and obesity seem to play a great role in BRS impairment.

  16. Is there an association between altered baroreceptor sensitivity and obstructive sleep apnoea in the healthy elderly?

    PubMed Central

    Martin, Magali Saint; Barthélémy, Jean Claude; Roche, Frédéric

    2016-01-01

    Obstructive sleep apnoea (OSA) is associated with a rise in cardiovascular risk in which increased sympathetic activity and depressed baroreceptor reflex sensitivity (BRS) have been proposed. We examined this association in a sample of healthy elderly subjects with unrecognised OSA. 801 healthy elderly (aged ≥65 years) subjects undergoing clinical, respiratory polygraphy and vascular assessment were examined. According to the apnoea–hypopnoea index (AHI), the subjects were stratified into no OSA, mild–moderate OSA and severe OSA cases. OSA was present in 62% of the sample, 62% being mild–moderate and 38% severe. No differences were found for BRS value according to sex and OSA severity. 54% of the group had normal BRS value, 36% mild impairment and 10% severe dysfunction. BRS was negatively associated with body mass index (p=0.006), 24-h systolic (p=0.001) and diastolic pressure (p=0.001), and oxygen desaturation index (ODI) (p=0.03). Regression analyses revealed that subjects with lower BRS were those with hypertension (OR 0.41, 95% CI 0.24–0.81; p=0.002) and overweight (OR 0.42, 95% CI 0.25–0.81; p=0.008), without the effect of AHI and ODI. In the healthy elderly, the presence of a severe BRS dysfunction affects a small amount of severe cases without effect on snorers and mild OSA. Hypertension and obesity seem to play a great role in BRS impairment. PMID:27957483

  17. Neurotransmission of autonomic components of aortic baroreceptor afferents in the NTS of awake rats.

    PubMed

    Machado, B H; Castania, J A; Bonagamba, L G; Salgado, H C

    2000-07-01

    The effect of sequential blockade of N-methyl-D-aspartic acid (NMDA) receptors with DL-2-amino-5-phosphonopentanoic acid (AP-5) and non-NMDA receptors with 6,7-dinitroquinoxaline-2,3 dione (DNQX) in the nucleus tractus solitarii (NTS) on the cardiovascular responses to electrical stimulation (ES) of the aortic depressor nerve (ADN) was evaluated in awake rats. Two protocols were used. In protocol 1, bilateral microinjection of AP-5 into the NTS (n = 7) reduced the hypotensive response to ES of the ADN; subsequent microinjection of DNQX produced additional reduction in this response. AP-5 reduced the bradycardic response, and DNQX almost abolished this response. In protocol 2, bilateral microinjection of DNQX into the NTS (n = 6) reduced the hypotensive response, and subsequent microinjection of AP-5 significantly reduced this response. DNQX produced a significant reduction in bradycardic response, and AP-5 abolished this response. The data indicate that processing of the parasympathetic component of the NTS aortic baroreceptor afferents is mediated by both NMDA and non-NMDA receptors, whereas processing of the sympathoinhibitory component seems to be only partially mediated by ionotropic receptors.

  18. The predictive value of arterial stiffness on major adverse cardiovascular events in individuals with mildly impaired renal function

    PubMed Central

    Han, Jie; Wang, Xiaona; Ye, Ping; Cao, Ruihua; Yang, Xu; Xiao, Wenkai; Zhang, Yun; Bai, Yongyi; Wu, Hongmei

    2016-01-01

    Objectives Despite growing evidence that arterial stiffness has important predictive value for cardiovascular disease in patients with advanced stages of chronic kidney disease, the predictive significance of arterial stiffness in individuals with mildly impaired renal function has not been established. The aim of this study was to evaluate the predictive value of arterial stiffness on cardiovascular disease in this specific population. Materials and methods We analyzed measurements of arterial stiffness (carotid–femoral pulse-wave velocity [cf-PWV]) and the incidence of major adverse cardiovascular events (MACEs) in 1,499 subjects from a 4.8-year longitudinal study. Results A multivariate Cox proportional-hazard regression analysis showed that in individuals with normal renal function (estimated glomerular filtration rate [eGFR] ≥90 mL/min/1.73 m2), the baseline cf-PWV was not associated with occurrence of MACEs (hazard ratio 1.398, 95% confidence interval 0.748–2.613; P=0.293). In individuals with mildly impaired renal function (eGFR <90 mL/min/1.73 m2), a higher baseline cf-PWV level was associated with a higher risk of MACEs (hazard ratio 2.334, 95% confidence interval 1.082–5.036; P=0.031). Conclusion Arterial stiffness is a moderate and independent predictive factor for MACEs in individuals with mildly impaired renal function (eGFR <90 mL/min/1.73 m2). PMID:27621605

  19. Anatomical and Functional Estimations of Brachial Artery Diameter and Elasticity Using Oscillometric Measurements with a Quantitative Approach.

    PubMed

    Yoshinaga, Keiichiro; Fujii, Satoshi; Tomiyama, Yuuki; Takeuchi, Keisuke; Tamaki, Nagara

    2016-07-01

    Noninvasive vascular function measurement plays an important role in detecting early stages of atherosclerosis and in evaluating therapeutic responses. In this regard, recently, new vascular function measurements have been developed. These new measurements have been used to evaluate vascular function in coronary arteries, large aortic arteries, or peripheral arteries. Increasing vascular diameter represents vascular remodeling related to atherosclerosis. Attenuated vascular elasticity may be a reliable marker for atherosclerotic risk assessment. However, previous measurements for vascular diameter and vascular elasticity have been complex, operator-dependent, or invasive. Therefore, simple and reliable approaches have been sought. We recently developed a new automated oscillometric method to measure the estimated area (eA) of a brachial artery and its volume elastic modulus (VE). In this review, we further report on this new measurement and other vascular measurements. We report on the reliability of the new automated oscillometric measurement of eA and VE. Based on our findings, this measurement technique should be a reliable approach, and this modality may have practical application to automatically assess muscular artery diameter and elasticity in clinical or epidemiological settings. In this review, we report the characteristics of our new oscillometric measurements and other related vascular function measurements.

  20. Anatomical and Functional Estimations of Brachial Artery Diameter and Elasticity Using Oscillometric Measurements with a Quantitative Approach

    PubMed Central

    Yoshinaga, Keiichiro; Fujii, Satoshi; Tomiyama, Yuuki; Takeuchi, Keisuke; Tamaki, Nagara

    2016-01-01

    Noninvasive vascular function measurement plays an important role in detecting early stages of atherosclerosis and in evaluating therapeutic responses. In this regard, recently, new vascular function measurements have been developed. These new measurements have been used to evaluate vascular function in coronary arteries, large aortic arteries, or peripheral arteries. Increasing vascular diameter represents vascular remodeling related to atherosclerosis. Attenuated vascular elasticity may be a reliable marker for atherosclerotic risk assessment. However, previous measurements for vascular diameter and vascular elasticity have been complex, operator-dependent, or invasive. Therefore, simple and reliable approaches have been sought. We recently developed a new automated oscillometric method to measure the estimated area (eA) of a brachial artery and its volume elastic modulus (VE). In this review, we further report on this new measurement and other vascular measurements. We report on the reliability of the new automated oscillometric measurement of eA and VE. Based on our findings, this measurement technique should be a reliable approach, and this modality may have practical application to automatically assess muscular artery diameter and elasticity in clinical or epidemiological settings. In this review, we report the characteristics of our new oscillometric measurements and other related vascular function measurements. PMID:27493898

  1. Peripheral endothelial function and arterial stiffness in women with migraine with aura: a case-control study.

    PubMed

    Liman, T G; Neeb, L; Rosinski, J; Wellwood, I; Reuter, U; Doehner, W; Heuschmann, P U; Endres, M

    2012-04-01

    Vascular dysfunction may be involved in migraine pathophysiology and contribute to the increased risk of ischemic stroke in migraine, particularly in women with migraine with aura (MA). However, data on endothelial function in MA are controversial. Here, we investigated whether systemic endothelial function and arterial stiffness are altered in women with MA, using a novel peripheral arterial tonometry device for the first time. Twenty-nine female MA patients without comorbidities and 30 healthy women were included, and carotid intima-media thickness was assessed by a standardized procedure. Endothelial function was assessed using peripheral arterial tonometry. Reactive hyperaemic response of digital pulse amplitude was measured following 5 minutes of forearm occlusion of the brachial artery. Arterial stiffness was assessed by fingertip tonometry derived and heart-rate-adjusted augmentation index. No differences were found in peripheral arterial tonometry ratio (2.3 ± 0.6 vs 2.2 ± 0.8; p = 0.58) and left carotid intima-media thickness (in µm: 484 ± 119 vs 508 ± 60; p = 0.37). Women with MA had higher heart-rate-averaged augmentation index [median (interquartile range, IQR) of 5 (IQR 0.5 to 18) vs -5 (IQR -16.8 to 8.3), p = 0.005] and heart-rate-adjusted augmentation index [1 (IQR -6 to 12.5) vs -8 (IQR -20.3 to 2.5), p = 0.008] than healthy controls. Peripheral endothelial function is not impaired in women with MA, but they have greater arterial stiffness. This may contribute to the increased stroke risk in women with MA.

  2. Functional differences between the arteries perfusing gas exchange and nutritional membranes in the late chicken embryo.

    PubMed

    Mohammed, Riazudin; Cavallaro, Giacomo; Kessels, Carolina G A; Villamor, Eduardo

    2015-10-01

    The chicken extraembryonic arterial system comprises the allantoic arteries, which irrigate the gas exchange organ (the chorioallantoic membrane, CAM) and the yolk sac (YS) artery, which irrigates the nutritional organ (the YS membrane). We compared, using wire myography, the reactivity of allantoic and YS arteries from 19-day chicken embryos (total incubation 21 days). The contractions induced by KCl, the adrenergic agonists norepinephrine (NE, nonselective), phenylephrine (α1), and oxymetazoline (α2), electric field stimulation (EFS), serotonin, U46619 (TP receptor agonist), and endothelin (ET)-1 and the relaxations induced by acetylcholine (ACh), sodium nitroprusside (SNP, NO donor), forskolin (adenylate cyclase activator), and isoproterenol (β-adrenergic agonist) were investigated. Extraembryonic allantoic arteries did not show α-adrenergic-mediated contraction (either elicited by exogenous agonists or EFS) or ACh-induced (endothelium-dependent) relaxation, whereas these responses were present in YS arteries. Interestingly, the intraembryonic segment of the allantoic artery showed EFS- and α-adrenergic-induced contraction and ACh-mediated relaxation. Moreover, glyoxylic acid staining showed the presence of catecholamine-containing nerves in the YS and the intraembryonic allantoic artery, but not in the extraembryonic allantoic artery. Isoproterenol- and forskolin-induced relaxation and ET-1-induced contraction were higher in YS than in allantoic arteries, whereas serotonin- and U46619-induced contraction and SNP-induced relaxation did not significantly differ between the two arteries. In conclusion, our study demonstrates a different pattern of reactivity in the arteries perfusing the gas exchange and the nutritional membranes of the chicken embryo.

  3. Catheter-based anatomic and functional assessment of coronary arteries in anomalous aortic origin of a coronary artery, myocardial bridges and Kawasaki disease.

    PubMed

    Qureshi, Athar M; Agrawal, Hitesh

    2017-06-13

    Most diagnostic testing in patients with anomalous aortic origins of coronary arteries, myocardial bridges, and coronary artery changes after Kawasaki disease are performed with the use of noninvasive techniques. In some cases, however, further diagnostic information is needed to guide the clinician in treating these patients. In such instances, cardiac catheterization with invasive anatomic and functional testing is an invaluable tool. Moreover, interventional treatment in the cardiac catheterization laboratory may be performed in a small subset of these patients. As the diagnosis of these conditions is now becoming more common, it is important for pediatric interventional cardiologists to be familiar with these techniques. In this article, the role of angiography, intravascular ultrasound, fractional flow reserve, and optical coherence tomography in these patients is reviewed. © 2017 Wiley Periodicals, Inc.

  4. Effect of coronary artery recanalization on right ventricular function in patients with acute myocardial infarction

    SciTech Connect

    Verani, M.S.; Tortoledo, F.E.; Batty, J.W.; Raizner, A.E.

    1985-05-01

    The effects of coronary artery recanalization by intracoronary administration of streptokinase on left ventricular function during acute myocardial infarction have received increasing attention in recent years. Although myocardial dysfunction is often more pronounced in the right ventricle than in the left ventricle in patients with acute inferior wall myocardial infarction, the effect of coronary artery recanalization on right ventricular dysfunction has not been previously addressed. Accordingly, in this investigation, 54 patients who participated in a prospective, controlled, randomized trial of recanalization during acute myocardial infarction were studied. Among 30 patients with inferior wall infarction, 19 had right ventricular dysfunction on admission; 11 of these 19 had positive uptake of technetium-99m pyrophosphate in the right ventricle, indicative of right ventricular infarction. Patients with successful recanalization exhibited improved right ventricular ejection fraction from admission to day 10. However, control patients and patients who did not undergo recanalization also exhibited improvement. These data indicate that the right ventricular dysfunction commonly associated with inferior wall infarction is often transient, and improvement is the rule, irrespective of early recanalization of the infarct vessel.

  5. Blood pressure, arterial function, structure, and aging: the role of hormonal replacement therapy in postmenopausal women.

    PubMed

    Scuteri, Angelo; Ferrucci, Luigi

    2003-01-01

    The occurrence of natural menopause may indicate that a woman is entering a period of increased risk for cardiovascular disease, due to both chronologic aging and lower levels of estrogen. This brief review aims to demonstrate the relevance of changes in blood pressure and large artery structure and function occurring after menopause. These changes, i.e., thickening and stiffening of large arteries (which, in turn would also result in increased systolic and pulse pressures), were found to predict subsequent cardiovascular events, independently of other known cardiovascular risk. The benefits of early hormone replacement therapy on the life expectancy of women have dramatically lost consensus since publication of the Womens Health Initiative study results. However, the authors believe that those results should increase the attention paid by clinicians and public health researchers to the individualization of hormone replacement therapy prescription for postmenopausal women, and to a better characterization of those vascular parameters and profiles identifying postmenopausal women who are most likely to benefit from specific hormone replacement therapy in terms of cardiovascular protection.

  6. Polymeric stent materials dysregulate macrophage and endothelial cell functions: implications for coronary artery stent

    PubMed Central

    Wang, Xintong; Zachman, Angela L.; Chun, Young Wook; Shen, Fang-Wen; Hwang, Yu-Shik; Sung, Hak-Joon

    2014-01-01

    Background Biodegradable polymers have been applied as bulk or coating materials for coronary artery stents. The degradation of polymers, however, could induce endothelial dysfunction and aggravate neointimal formation. Here we use polymeric microparticles to simulate and demonstrate the effects of degraded stent materials on phagocytic activity, cell death and dysfunction of macrophages and endothelial cells. Methods Microparticles made of low molecular weight polyesters were incubated with human macrophages and coronary artery endothelial cells (ECs). Microparticle-induced phagocytosis, cytotoxicity, apoptosis, cytokine release and surface marker expression were determined by immunostaining or ELISA. Elastase expression was analyzed by ELISA and the elastase-mediated polymer degradation was assessed by mass spectrometry. Results We demonstrated poly(D,L-lactic acid) (PLLA) and polycaprolactone (PCL) microparticles induced cytotoxicity in macrophages and ECs, partially through cell apoptosis. The particle treatment alleviated EC phagocytosis, as opposed to macrophages, but enhanced the expression of vascular cell adhesion molecule-1 (VCAM) along with decreased nitric oxide production, indicating ECs were activated and lost their capacity to maintain homeostasis. The activation of both cell types induced release of elastase or elastase-like protease, which further accelerated polymer degradation. Conclusions This study revealed that low molecule weight PLLA and PCL microparticles increased cytotoxicity and dysregulated endothelial cell function, which in turn enhanced elastase release and polymer degradation. These indicate polymer or polymer-coated stents impose a risk of endothelial dysfunction after deployment which can potentially lead to delayed endothelialization, neointimal hyperplasia and late thrombosis. PMID:24820736

  7. Functional assessment of cerebral artery stenosis: A pilot study based on computational fluid dynamics.

    PubMed

    Liu, Jia; Yan, Zhengzheng; Pu, Yuehua; Shiu, Wen-Shin; Wu, Jianhuang; Chen, Rongliang; Leng, Xinyi; Qin, Haiqiang; Liu, Xin; Jia, Baixue; Song, Ligang; Wang, Yilong; Miao, Zhongrong; Wang, Yongjun; Liu, Liping; Cai, Xiao-Chuan

    2017-07-01

    The fractional pressure ratio is introduced to quantitatively assess the hemodynamic significance of severe intracranial stenosis. A computational fluid dynamics-based method is proposed to non-invasively compute the FPRCFD and compared against fractional pressure ratio measured by an invasive technique. Eleven patients with severe intracranial stenosis considered for endovascular intervention were recruited and an invasive procedure was performed to measure the distal and the aortic pressure ( Pd and Pa). The fractional pressure ratio was calculated as [Formula: see text]. The computed tomography angiography was used to reconstruct three-dimensional (3D) arteries for each patient. Cerebral hemodynamics was then computed for the arteries using a mathematical model governed by Navier-Stokes equations and with the outflow conditions imposed by a model of distal resistance and compliance. The non-invasive [Formula: see text], [Formula: see text], and FPRCFD were then obtained from the computational fluid dynamics calculation using a 16-core parallel computer. The invasive and non-invasive parameters were tested by statistical analysis. For this group of patients, the computational fluid dynamics method achieved comparable results with the invasive measurements. The fractional pressure ratio and FPRCFD are very close and highly correlated, but not linearly proportional, with the percentage of stenosis. The proposed computational fluid dynamics method can potentially be useful in assessing the functional alteration of cerebral stenosis.

  8. Functional polymorphisms in matrix metalloproteinases -1, -3, -9 and -12 in relation to cervical artery dissection

    PubMed Central

    Buss, Armin; Pech, Katrin; Roelver, Susanne; Bloemeke, Brunhilde; Klotzsch, Christoph; Breuer, Sebastian

    2009-01-01

    Background Cervical artery dissection is a leading cause of cerebral ischemia in young adults. Morphological investigations have shown alterations in the extracellular matrix (ECM) of affected vessel walls. As matrix metalloproteinases (MMP) play a central role in the regulation of the ECM, an increased expression of these enzymes might lead to the endothelial damage in spontaneous cervical artery dissection (sCAD). Five different DNA polymorphisms in MMP-1, -3, -9 and -12 were tested for their frequency in patients with sCAD and compared with those of a control population. Methods Blood was sampled from 70 unrelated patients presenting consecutively in the department of neurology of the Aachen University Medical School with sCAD and from 87 control subjects living in the same area as the patients. The MMP polymorphisms were analyzed with hybridization probes using the LightCycler™ (Roche Diagnostics), by sequencing using the ABI 310 Genetic Analyzer (Applied Biosystems) and with the GeneScan program on a ABI 310 Genetic Analyzer. Results No statistically significant differences in the allelic distribution were found between sCAD patients and the controls. Conclusion Alleles of these 5 functional polymorphisms of MMPs seem not to be associated with structural alterations in the blood vessel wall of sCAD patients. However, this does not exclude a pathogenetic role for MMPs in sCAD via secondary factors such as cytokines that are able to induce these enzymes in cervical blood vessel walls. PMID:19664242

  9. Pulmonary Artery Dilation and Right Ventricular Function in Acute Kawasaki Disease.

    PubMed

    Numano, Fujito; Shimizu, Chisato; Tremoulet, Adriana H; Dyar, Dan; Burns, Jane C; Printz, Beth F

    2016-03-01

    Coronary artery inflammation and aneurysm formation are the most common complications of Kawasaki disease (KD). Valvulitis and myocarditis are also well described and may lead to valvar regurgitation and left ventricular dysfunction. However, functional changes in the right heart have rarely been reported. We noted several acute KD patients with dilated pulmonary arteries (PA) and thus sought to systematically characterize PA size and right-heart function in an unselected cohort of KD patients cared for at a single clinical center. Clinical, laboratory, and echocardiographic data from 143 acute KD subjects were analyzed. PA dilation was documented in 23 subjects (16.1 %); these subjects had higher median right ventricle myocardial performance index (RV MPI), higher ratio of early tricuspid inflow velocity to tricuspid annular early diastolic velocity (TV E/e'), and lower median TV e' velocity compared to the non-PA dilation group (0.50 vs 0.38 p < 0.01, 4.2 vs 3.6 p < 0.05, and 13.5 vs 15.2 cm/s p < 0.01, respectively). Almost all subjects with PA dilation had improved PA Z-score, RV MPI, and TV E/e' in the subacute phase (p < 0.01). There were no significant differences in indices of left ventricle function between PA dilation group and non-PA dilation group. In summary, PA dilation was documented in 16 % of acute KD subjects. These subjects were more likely to have echocardiographic indices consistent with isolated RV dysfunction that improved in the subacute phase. The long-term consequence of these findings will require longitudinal studies of this patient population.

  10. Collateral vessel number, plaque burden, and functional decline in peripheral artery disease.

    PubMed

    McDermott, Mary M; Carr, James; Liu, Kiang; Kramer, Christopher M; Yuan, Chun; Tian, Lu; Criqui, Michael H; Guralnik, Jack M; Ferrucci, Luigi; Zhao, Lihui; Xu, Dongxiang; Kibbe, Melina; Berry, Jarett; Carroll, Timothy J

    2014-08-01

    Associations of collateral vessels and lower extremity plaque with functional decline are unknown. Among people with peripheral artery disease (PAD), we determined whether greater superficial femoral artery (SFA) plaque burden combined with fewer lower extremity collateral vessels was associated with faster functional decline, compared to less plaque and/or more numerous collateral vessels. A total of 226 participants with ankle-brachial index (ABI) <1.00 underwent magnetic resonance imaging of lower extremity collateral vessels and cross-sectional imaging of the proximal SFA. Participants were categorized as follows: Group 1 (best), maximum plaque area < median and collateral vessel number ≥6 (median); Group 2, maximum plaque area < median and collateral vessel number <6; Group 3, maximum plaque area > median and collateral vessel number ≥6; Group 4 (worst), maximum plaque area > median and collateral vessel number <6. Functional measures were performed at baseline and annually for 2 years. Analyses adjust for age, sex, race, comorbidities, and other confounders. Annual changes in usual-paced walking velocity were: Group 1, +0.01 m/s; Group 2, -0.02 m/s; Group 3, -0.01 m/s; Group 4, -0.05 m/s (p-trend=0.008). Group 4 had greater decline than Group 1 (p<0.001), Group 2 (p=0.029), and Group 3 (p=0.010). Similar trends were observed for fastest-paced 4-meter walking velocity (p-trend=0.018). Results were not substantially changed when analyses were repeated with additional adjustment for ABI. However, there were no associations of SFA plaque burden and collateral vessel number with decline in 6-minute walk. In summary, a larger SFA plaque burden combined with fewer collateral vessels is associated with a faster decline in usual and fastest-paced walking velocity in PAD.

  11. [Effects of inhaled aerosolized iloprost in adult patients with pulmonary arterial hypertension on right heart functions].

    PubMed

    Guo, Xiao-xiao; Tian, Zhuang; Liu, Yong-tai; Wang, Qian; Li, Meng-tao; Zeng, Xiao-feng; Zhu, Wen-ling; Fang, Quan

    2011-11-01

    To explore the immediate effects of inhaled aerosolized iloprost on right heart function in adult patients with pulmonary arterial hypertension (PAH). A total of 30 PAH patients were recruited. Right heart catheterization and echocardiography were performed before and immediately after the inhalation of iloprost (20 µg). After inhalation, the values of mean pulmonary artery pressure (PAPm) and pulmonary vascular resistances (PVR) decreased markedly (42.5 ± 9.6 to 34.4 ± 11.9 mm Hg, P < 0.001; 9.6 ± 5.7 Wood unit to 7.1 ± 4.8 Wood unit, P < 0.001). And the value of tricuspid annular systolic motion peak velocity (TASm) increased markedly [(10.7 ± 2.1) cm/s vs (11.9 ± 2.5) cm/s, P < 0.01]. The baseline level of TASm was higher in acute responders than non-responders [(12.0 ± 2.2) cm/s vs (10.1 ± 1.8) cm/s, P = 0.01] and TASm increased markedly after inhalation in non-responders [(10.1 ± 1.8) cm/s vs (11.6 ± 2.3) cm/s, P < 0.01]. The inhalation of iloprost decreases the levels of PAPm and PVR and improve right heart functions in adult PAH patients. For non-responders, right heart function is worse and more benefits may be achieved after the inhalation of iloprost.

  12. Effects of sevoflurane on cardiopulmonary function in patients undergoing coronary artery bypass.

    PubMed

    Zhang, J; Wang, S

    2016-01-01

    The objective of the current study was to investigate effects of sevoflurane on cardiopulmonary function in patients undergoing coronary artery bypass grafting (CABG). In this study, 60 cases of patients with coronary heart disease (CHD) were selected and randomly divided into the sevoflurane group (group S) and the control group C (group C) with 30 cases in each group. The two groups received intravenous anesthesia. The patients of group C were only given oxygen mask and physiological saline to keep vein open; while the patients of group S were administered with 1% sevoflurane immediately after the beginning of cardiopulmonary bypass (CPB) until the end of the treatment. The cardiopulmonary functions at 30 min before operation (T0), postoperative 2 h (T1), 6h (T2), 24h (T3) and 48 (T4) were observed. The mean arterial pressure (MAP) of the group S at T1, T2, T3 was lower than that of the group C, as were the heart rate (HR) and left ventricular ejection fraction (LVEF). The creatine kinase isoenzyme (CK-MB) during T1 to T4 in the group S was less than that of the group C, and there were significant differences between the two groups (P less than 0.05). The tidal volume (Vt), vital capacity (Vc) and oxygenation index (PaO2/FiO2) of the two groups during T1 and T2 were decreased, while respiratory frequency (RR) and alveolar-arterial blood oxygen partial pressure (PA-aO2) were increased and they began to decrease during T3 and T4. Vt and Vc of the group S were higher during T1 and T2 periods than those of the group C, while RR was lower than that of the group C; PaO2 / FiO2 during T1 to T4 period of group S was higher than that of group C, while PA-aO2 was significantly lower than that of the control group (P less than 0.05). In conclusion, although LVEF was not improved in the sevoflurane group, sevoflurane may contribute to stabilizing the cardiopulmonary function and preventing from myocardial injury.

  13. Association of Skin Autofluorescence Levels With Kidney Function Decline in Patients With Peripheral Artery Disease.

    PubMed

    Schutte, Elise; de Vos, Lisanne C; Lutgers, Helen L; Lambers Heerspink, Hiddo J; Wolffenbuttel, Bruce H R; Vart, Priya; Zeebregts, Clark J; Gansevoort, Ron T; Lefrandt, Joop D

    2016-08-01

    Skin autofluorescence (SAF), a measure of advanced glycation end product accumulation, is associated with kidney function. We investigated the association of SAF with rate of kidney function decline in a cohort of patients with peripheral artery disease. We performed a post hoc analysis of an observational longitudinal cohort study. We included 471 patients with peripheral artery disease, and SAF was measured at baseline. Primary end point was rate of estimated glomerular filtration rate (eGFR) decline. Secondary end points were incidence of eGFR <60 and <45 mL/min/1.73 m(2) and rapid eGFR decline, defined as a decrease in eGFR of >5 mL/min/1.73 m(2)/y. During a median follow-up of 3 years, the mean change in eGFR per year was -1.8±4.4 mL/min/1.73 m(2)/y. No significant difference in rate of eGFR decline was observed per 1 arbitrary unit increase in SAF (-0.1 mL/min/1.73 m(2)/y; 95% confidence interval, -0.7 to 0.5; P=0.8). Analyses of the secondary end points showed that there was an association of SAF with incidence of eGFR <60 and <45 mL/min/1.73 m(2) (hazard ratio, 1.54; 95% confidence interval, 1.13-2.10; P=0.006 and hazard ratio, 1.76; 95% confidence interval, 1.20-2.59; P=0.004, respectively), but after adjustment for age and sex, significance was lost. There was no association of SAF with rapid eGFR decline. In conclusion, in this cohort of patients with peripheral artery disease, elevated SAF was associated with lower baseline eGFR. Although SAF has previously been established as a predictor for cardiovascular disease and mortality, it did not predict the rate of kidney function decline during follow-up in this study. © 2016 American Heart Association, Inc.

  14. Association between arterial stiffness and left ventricular diastolic function in relation to gender and age

    PubMed Central

    Kim, Hack-Lyoung; Lim, Woo-Hyun; Seo, Jae-Bin; Chung, Woo-Young; Kim, Sang-Hyun; Kim, Myung-A.; Zo, Joo-Hee

    2017-01-01

    Abstract Left ventricular (LV) diastolic dysfunction and subsequent overt heart failure are more prevalent in elderly women. Close interaction between arterial stiffness and LV morphology/function has been reported. The aim of this study was to investigate whether there is an age- and gender-dependent relationship between arterial stiffness and LV diastolic function. A total of 819 subjects (58.6 ± 13.3 years, 50.2% men) without structural heart disease (LV ejection fraction ≥50%) were retrospectively analyzed. All participants underwent transthoracic echocardiography and brachial-ankle pulse wave velocity (baPWV) measurement on the same day. The association of baPWV with septal e′ velocity and average E/e′ was assessed. In the total study subjects, baPWV was negatively correlated with septal e′ velocity (r = 0.383, P < 0.001), and positively correlated with E/e′ (r = −0.266, P < 0.001). These linear correlations remained significant even after stratificaion of the study subjects by age (<65 years vs ≥65 years) and genders (P < 0.05 for each). There were obvious differences in baPWV according to groups with normal LV diastolic function, intermediate profile and LV diastolic dysfunction in young (P = 0.010) and elderly (≥65 years) women (P < 0.001) and eldery men (P = 0.012) but not in elderly men (P = 0.270). There was a significant association of baPWV with septal e′ velocity (β = −0.258, P = 0.020) and E/e′ (β = 0.122, P = 0.030) in elderly women even after controlling for multiple clinical covariates. This independent association was not seen in younger women and men (P > 0.05 for each). In conclusion, baPWV was independently associated with septal e′ velocity and E/e′ in elderly women but not in younger women or men. The results of this study provide additional evidence that increased arterial stiffness plays an important role in the development of heart failure with

  15. Predictors of cognitive function in candidates for coronary artery bypass graft surgery.

    PubMed

    Ernest, Christine S; Elliott, Peter C; Murphy, Barbara M; Le Grande, Michael R; Goble, Alan J; Higgins, Rosemary O; Worcester, Marian U C; Tatoulis, James

    2007-03-01

    Candidates for coronary artery bypass graft surgery have been found to exhibit reduced cognitive function prior to surgery. However, little is known regarding the factors that are associated with pre-bypass cognitive function. A battery of neuropsychological tests was administered to a group of patients listed for bypass surgery (n = 109). Medical, sociodemographic and emotional predictors of cognitive function were investigated using structural equation modeling. Medical factors, namely history of hypertension and low ejection fraction, significantly predicted reduced cognitive function, as did several sociodemographic characteristics, namely older age, less education, non-English speaking background, manual occupation, and male gender. One emotional variable, confusion and bewilderment, was also a significant predictor whereas anxiety and depression were not. When significant predictors from the three sets of variables were included in a combined model, three of the five sociodemographic characteristics, namely age, non-English speaking background and occupation, and the two medical factors remained significant. Apart from sociodemographic characteristics, medical factors such as a history of hypertension and low ejection fraction significantly predicted reduced cognitive function in bypass candidates prior to surgery.

  16. Serum 25-hydroxyvitamin D and Ethnic Differences in Arterial Stiffness and Endothelial Function

    PubMed Central

    Alvarez, Jessica A.; Gower, Barbara A.; Calhoun, David A.; Judd, Suzanne E.; Dong, Yanbin; Dudenbostel, Tanja; Scholl, Jenni; Ashraf, Ambika P.

    2012-01-01

    Background Vitamin D reportedly influences vascular function, which is worse in African Americans (AAs) relative to European Americans (EAs). It is not clear if ethnic differences in 25(OH)D mediate differences in vascular function. This study examined the relationships of serum 25-hydroxyvitamin D (25(OH)D) with indicators of vascular function among healthy, young AA and EA adults. Methods This is a cross sectional study involving 23 AAs and 22 EAs. The main outcomes were augmentation index (AIx75), central aortic pressure, pulse wave velocity (PWV), flow-mediated dilation (FMD), and seated and supine blood pressures. Results Results indicated that 25(OH)D was inversely associated with AIx75, supine systolic blood pressure (SBP), central aortic SBP and central aortic diastolic blood pressure (DBP), independent of age, sex, and percent body fat (standardized β= -0.29 to -0.43, P < 0.05 for all). AAs had greater AIx75 (P = 0.04) and PWV (P = 0.07) and lower FMD (P = 0.02) compared to EA after adjusting for age and percent body fat; further adjustment for 25(OH)D reduced the ethnic differences (P = 0.44, 0.53, and 0.20, respectively). Conclusion The 25(OH)D was associated with vascular function in healthy adults, and lower 25(OH)D among AAs may contribute to their greater arterial stiffness and reduced endothelial function (Clinical trials.gov NCT01041365, NCT01041547). PMID:22719806

  17. Acute effect of iloprost inhalation on right atrial function and ventricular dyssynchrony in patients with pulmonary artery hypertension.

    PubMed

    Gabrielli, Luigi; Ocaranza, María Paz; Sitges, Marta; Kanacri, Andrés; Saavedra, Rodrigo; Sepulveda, Pablo; Sepulveda, Luis; Rossel, Victor; Zagolin, Monica; Verdejo, Hugo E; Baraona, Fernando; Zalaquett, Ricardo; Chiong, Mario; Lavandero, Sergio; Castro, Pablo F

    2017-01-01

    Right atrium function and ventricular function have significant prognostic value in pulmonary arterial hypertension patients. Acute changes in right ventricular synchrony and right atrium function postiloprost inhalation have not been evaluated. Cross-sectional study. Consecutive pulmonary arterial hypertension patients (group I from Nice classification) were included. Echocardiographic right atrium and right ventricular function pre- and postiloprost inhalation, including a right ventricular dyssynchrony index and right atrium function using speckle tracking, were performed in all patients. Twenty pulmonary arterial hypertension patients, 44±7 years and 90% females, were included. After iloprost inhalation, we observed a significant increment in right ventricular fractional area change and a significant decrease in right ventricular dyssynchrony index (21.4±5.6% vs 26.1±4.0 %, P=.007 and 79±44 vs 32±22 mseconds, P<.01, respectively), also an improvement in right atrium reservoir function (8.6±3.1% vs 11.7±3.5 %, P=.002). Iloprost inhalation induces acute changes in right ventricular function, dyssynchrony, and right atrium performance that may add relevant clinical information in the management and risk stratification of pulmonary arterial hypertension patients. © 2016, Wiley Periodicals, Inc.

  18. Cardiovascular function in space flight

    NASA Technical Reports Server (NTRS)

    Nicogossian, A. E.; Charles, J. B.; Bungo, M. W.; Leach-Huntoon, C. S.

    1990-01-01

    Postflight orthostatic intolerance and cardiac hemodynamics associated with manned space flight have been investigated on seven STS missions. Orthostatic heart rates appear to be influenced by the mission duration. The rates increase during the first 7-10 days of flight and recover partially after that. Fluid loading is used as a countermeasure to the postflight orthostatic intolerance. The carotid baroreceptor function shows only slight responsiveness to orthostatic stimulation. Plots of the baroreceptor function are presented. It is concluded that an early adaptation to the space flight conditions involves a fluid shift and that the subsequent alterations in the neutral controlling mechanisms contribute to the orthoststic intolerance.

  19. Cardiovascular function in space flight

    NASA Technical Reports Server (NTRS)

    Nicogossian, A. E.; Charles, J. B.; Bungo, M. W.; Leach-Huntoon, C. S.

    1990-01-01

    Postflight orthostatic intolerance and cardiac hemodynamics associated with manned space flight have been investigated on seven STS missions. Orthostatic heart rates appear to be influenced by the mission duration. The rates increase during the first 7-10 days of flight and recover partially after that. Fluid loading is used as a countermeasure to the postflight orthostatic intolerance. The carotid baroreceptor function shows only slight responsiveness to orthostatic stimulation. Plots of the baroreceptor function are presented. It is concluded that an early adaptation to the space flight conditions involves a fluid shift and that the subsequent alterations in the neutral controlling mechanisms contribute to the orthoststic intolerance.

  20. Heterogeneous function of ryanodine receptors, but not IP3 receptors, in hamster cremaster muscle feed arteries and arterioles.

    PubMed

    Westcott, Erika B; Jackson, William F

    2011-05-01

    The roles played by ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (IP₃Rs) in vascular smooth muscle in the microcirculation remain unclear. Therefore, the function of both RyRs and IP₃Rs in Ca(²+) signals and myogenic tone in hamster cremaster muscle feed arteries and downstream arterioles were assessed using confocal imaging and pressure myography. Feed artery vascular smooth muscle displayed Ca(²+) sparks and Ca(²+) waves, which were inhibited by the RyR antagonists ryanodine (10 μM) or tetracaine (100 μM). Despite the inhibition of sparks and waves, ryanodine or tetracaine increased global intracellular Ca(²+) and constricted the arteries. The blockade of IP₃Rs with xestospongin D (5 μM) or 2-aminoethoxydiphenyl borate (100 μM) or the inhibition of phospholipase C using U-73122 (10 μM) also attenuated Ca(2+) waves without affecting Ca(²+) sparks. Importantly, the IP₃Rs and phospholipase C antagonists decreased global intracellular Ca(2+) and dilated the arteries. In contrast, cremaster arterioles displayed only Ca(²+) waves: Ca(²+) sparks were not observed, and neither ryanodine (10-50 μM) nor tetracaine (100 μM) affected either Ca(²+) signals or arteriolar tone despite the presence of functional RyRs as assessed by responses to the RyR agonist caffeine (10 mM). As in feed arteries, arteriolar Ca(²+) waves were attenuated by xestospongin D (5 μM), 2-aminoethoxydiphenyl borate (100 μM), and U-73122 (10 μM), accompanied by decreased global intracellular Ca(²+) and vasodilation. These findings highlight the contrasting roles played by RyRs and IP₃Rs in Ca(²+) signals and myogenic tone in feed arteries and demonstrate important differences in the function of RyRs between feed arteries and downstream arterioles.

  1. Heterogeneous function of ryanodine receptors, but not IP3 receptors, in hamster cremaster muscle feed arteries and arterioles

    PubMed Central

    Westcott, Erika B.

    2011-01-01

    The roles played by ryanodine receptors (RyRs) and inositol 1,4,5-trisphosphate receptors (IP3Rs) in vascular smooth muscle in the microcirculation remain unclear. Therefore, the function of both RyRs and IP3Rs in Ca2+ signals and myogenic tone in hamster cremaster muscle feed arteries and downstream arterioles were assessed using confocal imaging and pressure myography. Feed artery vascular smooth muscle displayed Ca2+ sparks and Ca2+ waves, which were inhibited by the RyR antagonists ryanodine (10 μM) or tetracaine (100 μM). Despite the inhibition of sparks and waves, ryanodine or tetracaine increased global intracellular Ca2+ and constricted the arteries. The blockade of IP3Rs with xestospongin D (5 μM) or 2-aminoethoxydiphenyl borate (100 μM) or the inhibition of phospholipase C using U-73122 (10 μM) also attenuated Ca2+ waves without affecting Ca2+ sparks. Importantly, the IP3Rs and phospholipase C antagonists decreased global intracellular Ca2+ and dilated the arteries. In contrast, cremaster arterioles displayed only Ca2+ waves: Ca2+ sparks were not observed, and neither ryanodine (10–50 μM) nor tetracaine (100 μM) affected either Ca2+ signals or arteriolar tone despite the presence of functional RyRs as assessed by responses to the RyR agonist caffeine (10 mM). As in feed arteries, arteriolar Ca2+ waves were attenuated by xestospongin D (5 μM), 2-aminoethoxydiphenyl borate (100 μM), and U-73122 (10 μM), accompanied by decreased global intracellular Ca2+ and vasodilation. These findings highlight the contrasting roles played by RyRs and IP3Rs in Ca2+ signals and myogenic tone in feed arteries and demonstrate important differences in the function of RyRs between feed arteries and downstream arterioles. PMID:21357503

  2. Impaired renal function impacts negatively on vascular stiffness in patients with coronary artery disease

    PubMed Central

    2013-01-01

    Background Chronic kidney disease (CKD) and coronary artery disease (CAD) are independently associated with increased vascular stiffness. We examined whether renal function contributes to vascular stiffness independently of CAD status. Methods We studied 160 patients with CAD and 169 subjects without CAD. The 4-variable MDRD formula was used to estimate glomerular filtration rate (eGFR); impaired renal function was defined as eGFR <60 mL/min. Carotid-femoral pulse wave velocity (PWV) was measured with the SphygmoCor® device. Circulating biomarkers were assessed in plasma using xMAP® multiplexing technology. Results Patients with CAD and impaired renal function had greater PWV compared to those with CAD and normal renal function (10.2 [9.1;11.2] vs 7.3 [6.9;7.7] m/s; P < 0.001). In all patients, PWV was a function of eGFR (β = −0.293; P < 0.001) even after adjustment for age, sex, systolic blood pressure, body mass index and presence or absence of CAD. Patients with CAD and impaired renal function had higher levels of adhesion and inflammatory molecules including E-selectin and osteopontin (all P < 0.05) compared to those with CAD alone, but had similar levels of markers of oxidative stress. Conclusions Renal function is a determinant of vascular stiffness even in patients with severe atherosclerotic disease. This was paralleled by differences in markers of cell adhesion and inflammation. Increased vascular stiffness may therefore be linked to inflammatory remodeling of the vasculature in people with impaired renal function, irrespective of concomitant atherosclerotic disease. PMID:23937620

  3. Dependence of baroreceptor-mediated sympathetic outflow on biventricular assist device driving frequency.

    PubMed

    Yambe, T; Nitta, S; Katahira, Y; Sonobe, T; Naganuma, S; Kakinuma, Y; Akiho, H; Izutsu, K; Kikuchi, Y; Tanaka, M

    1993-01-01

    To investigate the drive condition of the artificial heart from a neurophysiological point of view, the dynamic transduction characteristics of the baroreflex system were analyzed by means of sympathetic neurograms. Two pneumatically actuated ventricular assist devices were implanted as biventricular bypasses (BVBs) in adult mongrel dogs to compare the natural heart circulation and prosthetic circulation. After BVB pumping was initiated, the natural heart was electrically fibrillated. Renal sympathetic nerve activity (RSNA) was recorded to analyze sympathetic outflow. Coherence function between the arterial pressure and RSNA was calculated to evaluate the linearity of the baroreflex system. The largest peak coherency was observed when BVB was driven at the frequency of natural heart beat prior to electrical fibrillation, which suggests that the baroreflex system shows the largest linearity at this frequency. These results suggest the possibility that the natural heart beat frequency is the setting frequency at which the baroreflex system transfers the hemodynamic rhythm to the sympathetic outflow.

  4. ITPKC functional polymorphism associated with Kawasaki disease susceptibility and formation of coronary artery aneurysms.

    PubMed

    Onouchi, Yoshihiro; Gunji, Tomohiko; Burns, Jane C; Shimizu, Chisato; Newburger, Jane W; Yashiro, Mayumi; Nakamura, Yoshikazu; Yanagawa, Hiroshi; Wakui, Keiko; Fukushima, Yoshimitsu; Kishi, Fumio; Hamamoto, Kunihiro; Terai, Masaru; Sato, Yoshitake; Ouchi, Kazunobu; Saji, Tsutomu; Nariai, Akiyoshi; Kaburagi, Yoichi; Yoshikawa, Tetsushi; Suzuki, Kyoko; Tanaka, Takeo; Nagai, Toshiro; Cho, Hideo; Fujino, Akihiro; Sekine, Akihiro; Nakamichi, Reiichiro; Tsunoda, Tatsuhiko; Kawasaki, Tomisaku; Nakamura, Yusuke; Hata, Akira

    2008-01-01

    Kawasaki disease is a pediatric systemic vasculitis of unknown etiology for which a genetic influence is suspected. We identified a functional SNP (itpkc_3) in the inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) gene on chromosome 19q13.2 that is significantly associated with Kawasaki disease susceptibility and also with an increased risk of coronary artery lesions in both Japanese and US children. Transfection experiments showed that the C allele of itpkc_3 reduces splicing efficiency of the ITPKC mRNA. ITPKC acts as a negative regulator of T-cell activation through the Ca2+/NFAT signaling pathway, and the C allele may contribute to immune hyper-reactivity in Kawasaki disease. This finding provides new insights into the mechanisms of immune activation in Kawasaki disease and emphasizes the importance of activated T cells in the pathogenesis of this vasculitis.

  5. ITPKC functional polymorphism associated with Kawasaki disease susceptibility and formation of coronary artery aneurysms

    PubMed Central

    Onouchi, Yoshihiro; Gunji, Tomohiko; Burns, Jane C; Shimizu, Chisato; Newburger, Jane W; Yashiro, Mayumi; Nakamura, Yoshikazu; Yanagawa, Hiroshi; Wakui, Keiko; Fukushima, Yoshimitsu; Kishi, Fumio; Hamamoto, Kunihiro; Terai, Masaru; Sato, Yoshitake; Ouchi, Kazunobu; Saji, Tsutomu; Nariai, Akiyoshi; Kaburagi, Yoichi; Yoshikawa, Tetsushi; Suzuki, Kyoko; Tanaka, Takeo; Nagai, Toshiro; Cho, Hideo; Fujino, Akihiro; Sekine, Akihiro; Nakamichi, Reiichiro; Tsunoda, Tatsuhiko; Kawasaki, Tomisaku; Nakamura, Yusuke; Hata, Akira

    2010-01-01

    Kawasaki disease is a pediatric systemic vasculitis of unknown etiology for which a genetic influence is suspected. We identified a functional SNP (itpkc_3) in the inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) gene on chromosome 19q13.2 that is significantly associated with Kawasaki disease susceptibility and also with an increased risk of coronary artery lesions in both Japanese and US children. Transfection experiments showed that the C allele of itpkc_3 reduces splicing efficiency of the ITPKC mRNA. ITPKC acts as a negative regulator of T-cell activation through the Ca2+/NFAT signaling pathway, and the C allele may contribute to immune hyper-reactivity in Kawasaki disease. This finding provides new insights into the mechanisms of immune activation in Kawasaki disease and emphasizes the importance of activated T cells in the pathogenesis of this vasculitis. PMID:18084290

  6. The effect of septoplasty on pulmonary artery pressure and right ventricular function in nasal septum deviation.

    PubMed

    Ozkececi, Gulay; Akci, Onder; Bucak, Abdulkadir; Ulu, Sahin; Yalım, Zafer; Aycicek, Abdullah; Onrat, Ersel; Avsar, Alaettin

    2016-11-01

    Nasal septum deviation (NSD) can cause obstruction of the upper airway, which may lead to increased pulmonary artery pressure (PAP) and right ventricle dysfunction. The aim of the present study was to evaluate the effect of septoplasty on right ventricular function and mean PAP of patients with marked NSD. 25 patients with marked NSD (mean age = 31.8 ± 12.3 years) and 27 healthy volunteers (mean age = 34.5 ± 10.8 years) were enrolled. Echocardiography was performed for all subjects and right ventricular function and mean PAP were evaluated before and 3 months after septoplasty. Tricuspid annular plane systolic excursion (TAPSE) and tricuspid annulus early diastolic myocardial velocity (E') were significantly lower in patients with NSD than control subjects, while right ventricle myocardial performance index (RVMPI) and mean PAP were significantly higher (respectively, p = 0.006, 0.037, 0.049, 0.046). When preoperative and postoperative findings were compared, the mean PAP decreased whereas TAPSE increased significantly (respectively, p = 0.007, 0.03). The results of the present study demonstrated that mean PAP increased and right ventricular function worsened in patients with NSD. However, mean PAP decreased and right ventricular function tended to recover after septoplasty.

  7. The effects of functional electrical stimulation leg ergometry training on arterial compliance in individuals with spinal cord injury

    PubMed Central

    Zbogar, Dominik; Eng, Janice J.; Krassioukov, Andrei V.; Scott, Jessica M.; Esch, Ben T.A.; Warburton, Darren E.R.

    2011-01-01

    Study design A prospective intervention of functional electrical stimulation leg cycle ergometry (FES-LCE) of four women with spinal cord injury (SCI). Objective To evaluate the effect of FES-LCE training on arterial compliance in individuals with chronic SCI of traumatic origin. Setting Tertiary rehabilitation center in Canada. Methods Large and small artery compliance were measured at the radial artery before and after a 3 month training program using FES-LCE. Results There was no significant change in large artery compliance after FES-LCE (16.0 ± 4.2 to 16.8 ± 6.1 mL/mmHg × 10, p = n.s.). There was a marked (63%) increase in small artery compliance after the FES training program (4.2 ± 1.8 to 6.9 ± 3.2 mL/mmHg × 100, p < 0.05). Conclusion It appears that FES-LCE is effective in improving small artery compliance in females with SCI. PMID:18414425

  8. Non-clinical and Pre-clinical Testing to Demonstrate Safety of the Barostim Neo Electrode for Activation of Carotid Baroreceptors in Chronic Human Implants

    PubMed Central

    Wilks, Seth J.; Hara, Seth A.; Ross, Erika K.; Nicolai, Evan N.; Pignato, Paul A.; Cates, Adam W.; Ludwig, Kip A.

    2017-01-01

    The Barostim neo™ electrode was developed by CVRx, Inc.to deliver baroreflex activation therapy (BAT)™ to treat hypertension and heart failure. The neo electrode concept was designed to deliver electrical stimulation to the baroreceptors within the carotid sinus bulb, while minimizing invasiveness of the implant procedure. This device is currently CE marked in Europe, and in a Pivotal (akin to Phase III) Trial in the United States. Here we present the in vitro and in vivo safety testing that was completed in order to obtain necessary regulatory approval prior to conducting human studies in Europe, as well as an FDA Investigational Device Exemption (IDE) to conduct a Pivotal Trial in the United States. Stimulated electrodes (10 mA, 500 μs, 100 Hz) were compared to unstimulated electrodes using optical microscopy and several electrochemical techniques over the course of 27 weeks. Electrode dissolution was evaluated by analyzing trace metal content of solutions in which electrodes were stimulated. Lastly, safety testing under Good Laboratory Practice guidelines was conducted in an ovine animal model over a 12 and 24 week time period, with results processed and evaluated by an independent histopathologist. Long-term stimulation testing indicated that the neo electrode with a sputtered iridium oxide coating can be stimulated at maximal levels for the lifetime of the implant without clinically significant dissolution of platinum or iridium, and without increasing the potential at the electrode interface to cause hydrolysis or significant tissue damage. Histological examination of tissue that was adjacent to the neo electrodes indicated no clinically significant signs of increased inflammation and no arterial stenosis as a result of 6 months of continuous stimulation. The work presented here involved rigorous characterization and evaluation testing of the neo electrode, which was used to support its safety for chronic implantation. The testing strategies discussed

  9. Impaired microvascular reactivity and endothelial function in patients with Cushing's syndrome: influence of arterial hypertension.

    PubMed

    Prázný, M; Jezková, J; Horová, E; Lazárová, V; Hána, V; Kvasnicka, J; Pecen, L; Marek, J; Skrha, J; Krsek, M

    2008-01-01

    The aim of the study was to evaluate skin microvascular reactivity (MVR) and possible influencing factors (fibrinolysis, oxidative stress, and endothelial function) in patients with Cushing's syndrome. Twenty-nine patients with active Cushing's syndrome (ten of them also examined after a successful operation) and 16 control subjects were studied. Skin MVR was measured by laser Doppler flowmetry during post-occlusive (PORH) and thermal hyperemia (TH). Malondialdehyde and Cu,Zn-superoxide dismutase were used as markers of oxidative stress. Fibrinolysis was estimated by tissue plasminogen activator (tPA) and its inhibitor (PAI-1). N-acetyl-beta-glucosaminidase, E-selectin, P-selectin, and ICAM-1 were used as markers of endothelial function. Oxidative stress and endothelial dysfunction was present in patients with hypercortisolism, however, increased concentration of ICAM-1 was also found in patients after the operation as compared to controls (290.8+/-74.2 vs. 210.9+/-56.3 ng.ml(-1), p<0.05). Maximal perfusion was significantly lower in patients with arterial hypertension during PORH and TH (36.3+/-13.0 vs. 63.3+/-32.4 PU, p<0.01, and 90.4+/-36.6 vs. 159.2+/-95.3 PU, p<0.05, respectively) and similarly the velocity of perfusion increase during PORH and TH was lower (3.2+/-1.5 vs. 5.2+/-3.4 PU.s(-1), p<0.05, and 0.95+/-0.6 vs. 1.8+/-1.1 PU.s(-1), p<0.05, respectively). The most pronounced impairment of microvascular reactivity was present in patients with combination of arterial hypertension and diabetes mellitus.

  10. Mapping Long-Term Functional Changes in Cerebral Blood Flow by Arterial Spin Labeling

    PubMed Central

    Ssali, Tracy; Anazodo, Udunna C.; Bureau, Yves; MacIntosh, Bradley J.; Günther, Matthias; St. Lawrence, Keith

    2016-01-01

    Although arterial spin labeling (ASL) is appealing for mapping long-term changes in functional activity, inter-sessional variations in basal blood flow, arterial transit times (ATTs), and alignment errors, can result in significant false activation when comparing images from separate sessions. By taking steps to reduce these sources of noise, this study assessed the ability of ASL to detect functional CBF changes between sessions. ASL data were collected in three sessions to image ATT, resting CBF and CBF changes associated with motor activation (7 participants). Activation maps were generated using rest and task images acquired in the same session and from sessions separated by up to a month. Good agreement was found when comparing between-session activation maps to within-session activation maps with only a 16% decrease in precision (within-session: 90 ± 7%) and a 13% decrease in the Dice similarity (within-session: 0.75 ± 0.07) coefficient after a month. In addition, voxel-wise reproducibility (within-session: 4.7 ± 4.5%) and reliability (within-session: 0.89 ± 0.20) of resting grey-matter CBF decreased by less than 18% for the between-session analysis relative to within-session values. ATT variability between sessions (5.0 ± 2.7%) was roughly half the between-subject variability, indicating that its effects on longitudinal CBF were minimal. These results demonstrate that conducting voxel-wise analysis on CBF images acquired on different days is feasible with only modest loss in precision, highlighting the potential of ASL for longitudinal studies. PMID:27706218

  11. Is carotid sonography a useful tool for predicting functional capabilities in ischemic stroke patients following carotid artery stenting?

    PubMed Central

    Lin, Chih-Ming; Su, Jian-Chi; Chang, Yu-Jun; Liu, Chi-Kuang; Lu, Henry Horng-Shing; Jong, Yuh-Jyh

    2017-01-01

    Abstract Carotid stenosis is a major cause of stroke and timely intervention with stenting manipulation can significantly reduce the risk of secondary stroke. The impact of stenting procedures on patient functional capabilities has not yet been explored. The primary aim of this study was to examine associations between periprocedural carotid sonography parameters and post-treatment functional capabilities in stroke patients. Sixty-seven patients who received carotid stenting at 1 angiography laboratory were included. Prestenting and poststenting carotid duplex data were recorded and resistance index (RI) differences at various carotid system locations were compared. The modified Rankin Scale (mRS) was used to assess functional capability. All of the studied parameters were analyzed by SPSS (version 16.0, SPSS Inc, Chicago, IL). Following stenting, mRS scores improved (n = 44) or remained stationary (n = 23). Net contralateral internal carotid artery (ICA) RI for patients with improved mRS was lower compared to that for patients with stationary mRS (median = 0.040 vs 0.11; P = 0.003). The contralateral common carotid artery RI before and after stenting differed significantly (P < 0.050) in both. The ipsilateral ICA RI differed (P < 0.050) only in patients with improved mRS. The difference in mean transit time, Barthel index, net ipsilateral ICA RI, net contralateral external carotid artery RI, postipsilateral common carotid artery RI, and postipsilateral ICA RI differed significantly between different baseline stroke severity groups (P < 0.050). Carotid artery stenting improved physical function in a proportion of ischemic stroke patients with carotid stenosis. Carotid ultrasound is a useful assessment tool to predict likely functional outcomes following carotid artery stenting. PMID:28328821

  12. Endothelial function, arterial stiffness, and adherence to the 2010 Dietary Guidelines for Americans: a cross-sectional analysis

    PubMed Central

    Sauder, Katherine A.; Proctor, David N.; Chow, Mosuk; Troy, Lisa M.; Wang, Na; Vita, Joseph A.; Vasan, Ramachandran S.; Mitchell, Gary F.; Jacques, Paul F.; Hamburg, Naomi M.; West, Sheila G.

    2015-01-01

    Endothelial dysfunction and arterial stiffness are early predictors of cardiovascular disease. Intervention studies suggest that diet is related to vascular health, but most prior studies tested individual foods or nutrients and relied on small samples of younger adults. The purpose of this study was to examine relations between adherence to the 2010 Dietary Guidelines for Americans and vascular health in a large, cross-sectional analysis. In 5887 adults in the Framingham Heart Study Offspring and Third Generation cohorts, diet quality was quantified with the 2010 Dietary Guidelines for Americans Index (DGAI-2010). Endothelial function was assessed via brachial artery ultrasound and arterial stiffness via arterial tonometry. In age-, sex-, and cohort-adjusted analyses, higher DGAI-2010 score (greater adherence) was modestly associated with lower resting flow velocity, hyperemic response, mean arterial pressure, carotid-femoral pulse wave velocity, and augmentation index, but not associated with resting arterial diameter or flow-mediated dilation. In multivariable models adjusting for cardiovascular risk factors, only the association of higher DGAI-2010 with lower baseline flow and augmentation index persisted (β=−0.002, P=0.003 and β=−0.05 ± 0.02, P<0.001, respectively). Age-stratified multivariate-adjusted analyses suggested that the relation of higher DGAI-2010 scores with lower mean arterial pressure, pulse wave velocity, and augmentation index was more pronounced among adults younger than 50 years. Better adherence to the 2010 Dietary Guidelines for Americans, particularly in younger adults, is associated with lower peripheral blood flow velocity and arterial wave reflection but not flow-mediated dilation. Our results suggest a link between adherence to the Dietary Guidelines and favorable vascular health. PMID:25885520

  13. Molecular and functional characterization of Kv 7 channels in penile arteries and corpus cavernosum of healthy and metabolic syndrome rats.

    PubMed

    Jepps, T A; Olesen, S P; Greenwood, I A; Dalsgaard, T

    2016-05-01

    KCNQ-encoded voltage-dependent potassium channels (Kv 7) are involved in the regulation of vascular tone. In this study we evaluated the influence of Kv 7 channel activation on smooth muscle relaxation in rat penile arteries and corpus cavernosum from normal and spontaneously hypertensive, heart failure-prone (SHHF) rats - a rat model of human metabolic syndrome. Quantitative PCR and immunohistochemistry were used to determine the expression of KCNQ isoforms in penile tissue. Isometric tension was measured in intracavernous arterial rings and corpus cavernosum strips isolated from normal and SHHF rats. Transcripts for KCNQ3, KCNQ4 and KCNQ5 were detected in penile arteries and corpus cavernosum. KCNQ1 was only found in corpus cavernosum. Immunofluorescence signals to Kv 7.4 and Kv 7.5 were found in penile arteries, penile veins and corpus cavernosum. The Kv 7.2-7.5 activators, ML213 and BMS204352, relaxed pre-contracted penile arteries and corpus cavernosum independently of nitric oxide synthase or endothelium-derived hyperpolarization. Relaxations to sildenafil, a PDE5 inhibitor, and sodium nitroprusside (SNP), an nitric oxide donor, were reduced by blocking Kv 7 channels with linopirdine in penile arteries and corpus cavernosum. In SHHF rat penile arteries and corpus cavernosum, relaxations to ML213 and BMS204352 were attenuated, and the blocking effect of linopirdine on sildenafil-induced and SNP-induced relaxations reduced. KCNQ3, KCNQ4 and KCNQ5 were down-regulated, and KCNQ1 was up-regulated in corpus cavernosum from SHHF rats. KCNQ1-5 transcripts remained unchanged in penile arteries from SHHF rats. These data suggest that Kv 7 channels play a role in erectile function and contribute to the pathophysiology of erectile dysfunction, an early indicator of cardiovascular disease. © 2016 The British Pharmacological Society.

  14. Molecular and functional characterization of Kv7 channels in penile arteries and corpus cavernosum of healthy and metabolic syndrome rats

    PubMed Central

    Jepps, T A; Olesen, S P; Greenwood, I A

    2016-01-01

    Background and Purpose KCNQ‐encoded voltage‐dependent potassium channels (Kv7) are involved in the regulation of vascular tone. In this study we evaluated the influence of Kv7 channel activation on smooth muscle relaxation in rat penile arteries and corpus cavernosum from normal and spontaneously hypertensive, heart failure‐prone (SHHF) rats – a rat model of human metabolic syndrome. Experimental Approach Quantitative PCR and immunohistochemistry were used to determine the expression of KCNQ isoforms in penile tissue. Isometric tension was measured in intracavernous arterial rings and corpus cavernosum strips isolated from normal and SHHF rats. Key Results Transcripts for KCNQ3, KCNQ4 and KCNQ5 were detected in penile arteries and corpus cavernosum. KCNQ1 was only found in corpus cavernosum. Immunofluorescence signals to Kv7.4 and Kv7.5 were found in penile arteries, penile veins and corpus cavernosum. The Kv7.2–7.5 activators, ML213 and BMS204352, relaxed pre‐contracted penile arteries and corpus cavernosum independently of nitric oxide synthase or endothelium‐derived hyperpolarization. Relaxations to sildenafil, a PDE5 inhibitor, and sodium nitroprusside (SNP), an nitric oxide donor, were reduced by blocking Kv7 channels with linopirdine in penile arteries and corpus cavernosum. In SHHF rat penile arteries and corpus cavernosum, relaxations to ML213 and BMS204352 were attenuated, and the blocking effect of linopirdine on sildenafil‐induced and SNP‐induced relaxations reduced. KCNQ3, KCNQ4 and KCNQ5 were down‐regulated, and KCNQ1 was up‐regulated in corpus cavernosum from SHHF rats. KCNQ1–5 transcripts remained unchanged in penile arteries from SHHF rats. Conclusions and Implications These data suggest that Kv7 channels play a role in erectile function and contribute to the pathophysiology of erectile dysfunction, an early indicator of cardiovascular disease. PMID:26802314

  15. Multimarker assessment for the prediction of renal function improvement after percutaneous revascularization for renal artery stenosis

    PubMed Central

    Partovi, Sasan; Zeller, Thomas; Breidthardt, Tobias; Kaech, Max; Boeddinghaus, Jasper; Puelacher, Christian; Nestelberger, Thomas; Aschwanden, Markus; Mueller, Christian

    2016-01-01

    Background Identifying patients likely to have improved renal function after percutaneous transluminal renal angioplasty and stenting (PTRA) for renal artery stenosis (RAS) is challenging. The purpose of this study was to use a comprehensive multimarker assessment to identify those patients who would benefit most from correction of RAS. Methods In 127 patients with RAS and decreased renal function and/or hypertension referred for PTRA, quantification of hemodynamic cardiac stress using B-type natriuretic peptide (BNP), renal function using estimated glomerular filtration rate (eGFR), parenchymal renal damage using resistance index (RI), and systemic inflammation using C-reactive protein (CRP) were performed before intervention. Results Predefined renal function improvement (increase in eGFR ≥10%) at 6 months occurred in 37% of patients. Prognostic accuracy as quantified by the area under the receiver-operating characteristics curve for the ability of BNP, eGFR, RI and CRP to predict renal function improvement were 0.59 (95% CI, 0.48–0.70), 0.71 (95% CI, 0.61–0.81), 0.52 (95% CI, 0.41–0.65), and 0.56 (95% CI, 0.44–0.68), respectively. None of the possible combinations increased the accuracy provided by eGFR (lower eGFR indicated a higher likelihood for eGFR improvement after PTRA, P=ns for all). In the subgroup of 56 patients with pre-interventional eGFR <60 mL/min/1.73 m2, similar findings were obtained. Conclusions Quantification of renal function, but not any other pathophysiologic signal, provides at least moderate accuracy in the identification of patients with RAS in whom PTRA will improve renal function. PMID:27280085

  16. Impact of recovery of renal function on long-term mortality after coronary artery bypass grafting.

    PubMed

    Mehta, Rajendra H; Honeycutt, Emily; Patel, Uptal D; Lopes, Renato D; Shaw, Linda K; Glower, Donald D; Harrington, Robert A; Califf, Robert M; Sketch, Michael H

    2010-12-15

    Whether prognosis differs in acute renal failure (ARF) after coronary artery bypass grafting (CABG) in patients with and without recovery of renal function is not known. We studied patients who had CABG at Duke University Medical Center (1995 to 2008). ARF was defined as an increase in peak creatinine ≥50% after CABG or ≥0.7 mg/dl above baseline or need for new dialysis. Patients were categorized into 3 groups: (1) no ARF after CABG, (2) ARF after CABG and completely recovered renal function at day 7 (return of creatinine to no higher than baseline and no dialysis), or (3) ARF after CABG with no recovery of renal function at day 7 (creatinine no higher than baseline or new dialysis). Main outcome measurement was risk-adjusted long-term mortality (excluding death ≤7 days). ARF after CABG occurred in 2,083 of 10,415 patients (20%) and completely recovered in 703 (33.7%). Risk-adjusted mortality was highest in patients with ARF without recovery of renal function (hazard ratios 1.47, 95% confidence interval 1.34 to 1.62) and intermediate in those with ARF but completely recovered renal function (hazard ratios 1.21, 95% confidence interval 1.07 to 1.37, referent no-ARF group). Mortality was lower in patients with ARF compared to those without complete recovery of renal function (p = 0.0083). In conclusion, in patients with ARF after CABG, complete recovery of renal function was associated with significantly lower long-term mortality compared to those without such recovery, although this was significantly higher than in those without ARF. Thus, major emphasis should be on prevention of ARF in patients undergoing CABG.

  17. Severity of coronary artery disease is an independent risk factor for decline in kidney function.

    PubMed

    Turak, Osman; Afsar, Baris; Siriopol, Dimitrie; Yayla, Cagri; Oksuz, Fatih; Cagli, Kumral; Burlacu, Alexandru; Covic, Adrian; Kanbay, Mehmet

    2016-09-01

    Chronic kidney disease (CKD) and cardiovascular disease are closely interrelated and the presence of one condition synergistically affects the prognosis of the other, in a negative manner. There are surprisingly very few data on the relationship between baseline coronary artery disease (CAD) severity and subsequent decline in kidney function. We aimed to evaluate for the first time whether baseline coronary artery lesion severity predicts the decline in kidney function. The study population was derived from a series of consecutive patients presenting with stable angina pectoris or angina equivalents, who underwent coronary angiography. SYNTAX score for each patient was calculated to define severity of CAD. Change in kidney function was defined by calculating the rates of change in eGFR. Among the 823 patients included in our study, the mean age was 59.2±10.7years, 78.4% were males, and 32% had diabetes. The mean baseline eGFR was 87.3±24.9ml/min/1.73m(2) and the median Syntax score was 14 (IQR=10-20). The median length of follow-up was 2.75years (IQR=2.42-3.50). The mean yearly change for eGFR in the entire study population was 4.06 (95% CI: 3.59-4.51)ml/min/1.73m(2). A higher Syntax score was associated with a significantly faster decline in eGFR in all (unadjusted and adjusted) models. During the follow-up, 103 patients developed CKD. A higher Syntax score, analyzed both as continuous and categorical variable, was associated with incident CKD in all models. We have demonstrated for the first time that severity of CAD is an independent risk factor for the decline in kidney function. Studies are needed to highlight the potential mechanisms regarding the association between severity of CAD and decline in kidney function. Copyright © 2016 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  18. Regulation of sympathetic nervous system function after cardiovascular deconditioning

    NASA Technical Reports Server (NTRS)

    Hasser, E. M.; Moffitt, J. A.

    2001-01-01

    Humans subjected to prolonged periods of bed rest or microgravity undergo deconditioning of the cardiovascular system, characterized by resting tachycardia, reduced exercise capability, and a predisposition for orthostatic intolerance. These changes in cardiovascular function are likely due to a combination of factors, including changes in control of body fluid balance or cardiac alterations resulting in inadequate maintenance of stroke volume, altered arterial or venous vascular function, reduced activation of cardiovascular hormones, and diminished autonomic reflex function. There is evidence indicating a role for each of these mechanisms. Diminished reflex activation of the sympathetic nervous system and subsequent vasoconstriction appear to play an important role. Studies utilizing the hindlimb-unloaded (HU) rat, an animal model of deconditioning, evaluated the potential role of altered arterial baroreflex control of the sympathetic nervous system. These studies indicate that HU results in blunted baroreflex-mediated activation of both renal and lumbar sympathetic nerve activity in response to a hypotensive stimulus. HU rats are less able to maintain arterial pressure during hemorrhage, suggesting that diminished ability to increase sympathetic activity has functional consequences for the animal. Reflex control of vasopressin secretion appears to be enhanced following HU. Blunted baroreflex-mediated sympathoexcitation appears to involve altered central nervous system function. Baroreceptor afferent activity in response to changes in arterial pressure is unaltered in HU rats. However, increases in efferent sympathetic nerve activity for a given decrease in afferent input are blunted after HU. This altered central nervous system processing of baroreceptor inputs appears to involve an effect at the rostral ventrolateral medulla (RVLM). Specifically, it appears that tonic GABAA-mediated inhibition of the RVLM is enhanced after HU. Augmented inhibition apparently

  19. Regulation of sympathetic nervous system function after cardiovascular deconditioning

    NASA Technical Reports Server (NTRS)

    Hasser, E. M.; Moffitt, J. A.

    2001-01-01

    Humans subjected to prolonged periods of bed rest or microgravity undergo deconditioning of the cardiovascular system, characterized by resting tachycardia, reduced exercise capability, and a predisposition for orthostatic intolerance. These changes in cardiovascular function are likely due to a combination of factors, including changes in control of body fluid balance or cardiac alterations resulting in inadequate maintenance of stroke volume, altered arterial or venous vascular function, reduced activation of cardiovascular hormones, and diminished autonomic reflex function. There is evidence indicating a role for each of these mechanisms. Diminished reflex activation of the sympathetic nervous system and subsequent vasoconstriction appear to play an important role. Studies utilizing the hindlimb-unloaded (HU) rat, an animal model of deconditioning, evaluated the potential role of altered arterial baroreflex control of the sympathetic nervous system. These studies indicate that HU results in blunted baroreflex-mediated activation of both renal and lumbar sympathetic nerve activity in response to a hypotensive stimulus. HU rats are less able to maintain arterial pressure during hemorrhage, suggesting that diminished ability to increase sympathetic activity has functional consequences for the animal. Reflex control of vasopressin secretion appears to be enhanced following HU. Blunted baroreflex-mediated sympathoexcitation appears to involve altered central nervous system function. Baroreceptor afferent activity in response to changes in arterial pressure is unaltered in HU rats. However, increases in efferent sympathetic nerve activity for a given decrease in afferent input are blunted after HU. This altered central nervous system processing of baroreceptor inputs appears to involve an effect at the rostral ventrolateral medulla (RVLM). Specifically, it appears that tonic GABAA-mediated inhibition of the RVLM is enhanced after HU. Augmented inhibition apparently

  20. Minimized extracorporeal circulation does not impair cognitive brain function after coronary artery bypass grafting.

    PubMed

    Reineke, David; Winkler, Bernhard; König, Tobias; Meszaros, Katharina; Sodeck, Gottfried; Schönhoff, Florian; Erdoes, Gabor; Czerny, Martin; Carrel, Thierry

    2015-01-01

    Objective evaluation of the impact of minimized extracorporeal circulation (MECC) on perioperative cognitive brain function in coronary artery bypass grafting (CABG) by electroencephalogram P300 wave event-related potentials and number connection test (NCT) as metrics of cognitive function. Cognitive brain function was assessed in 31 patients in 2013 with a mean age of 65 years [standard deviation (SD) 10] undergoing CABG by the use of MECC with P300 auditory evoked potentials (peak latencies in milliseconds) directly prior to intervention, 7 days after and 3 months later. Number connection test, serving as method of control, was performed simultaneously in all patients. Seven days following CABG, cognitive P300 evoked potentials were comparable with preoperative baseline values [vertex (Cz) 376 (SD 11) ms vs 378 (18) ms, P = 0.39; frontal (Fz) 377 (11) vs 379 (21) ms, P = 0.53]. Cognitive brain function at 3 months was compared with baseline values [(Cz) 376 (11) ms vs 371 (14 ms) P = 0.09; (Fz) 377 (11) ms vs 371 (15) ms, P = 0.04]. Between the first postoperative measurement and 3 months later, significant improvement was observed [(Cz) 378 (18) ms vs 371 (14) ms, P = 0.03; (Fz) 379 (21) vs 371 (15) ms, P = 0.02]. Similar clearly corresponding patterns could be obtained via the number connection test. Results could be confirmed in repeated measures analysis of variance for Cz (P = 0.05) and (Fz) results (P = 0.04). MECC does not adversely affect cognitive brain function after CABG. Additionally, these patients experience a substantial significant cognitive improvement after 3 months, evidentiary proving that the concept of MECC ensures safety and outcome in terms of brain function. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  1. MRI-derived arterial input functions for PET kinetic modelling in rats

    NASA Astrophysics Data System (ADS)

    Evans, Eleanor; Sawiak, Stephen J.; Adrian Carpenter, T.

    2013-02-01

    Simultaneous PET-MR acquisition provides the high temporal and spatial resolution of MRI with the specificity of PET. In PET, accurate modelling of physiological function in vivo requires the time-activity curve of tracer in blood plasma, known as the arterial input function (AIF). As the gold standard method of blood sampling is inherently prohibitive in the small animal case, here we discuss how we prepare to rapidly sample MRI signals from gadolinium-doped tracer to obtain the tracer input functions from a simultaneous PET-MR measurement. ΔR2* measurements taken from EPI images were used to obtain first pass bolus AIFs in the rat brain from DSC-MRI datasets of 5 rats. AIFs obtained using our automatic algorithm were found to be consistent between animals and compared well with manual methods without need for a priori voxel selection. A variable flip angle FLASH sequence used for T1 mapping was successfully tested in a phantom study, providing accurate measurements of Gd concentration.

  2. [Effect of sanatorium treatment on endothelial function in children with primary arterial hypertension].

    PubMed

    Ianina, T Iu

    2014-01-01

    To study the effect of sanatorium treatment (ST) using sodium chloride baths and metabolic drug mildronat on the dynamics of the ambulatory blood pressure monitoring (ABPM), markers of endothelial function in children with primary arterial hypertension (PAH). ABPM and held defined level of asymmetric dimethylarginine (ADMA), endothelin-1 (ET-1) and nitric oxide (NO) in the serum of 114 children with PAH aged 12-17. The positive dynamics of ABPM in all groups, but significantly (P < 0.05) decrease in mean BP was noted in the group with combined ST using sodium chloride baths. When analyzing the level of NO a positive trend (P < 0.01) in the group was using metabolic therapy, but significantly (P < 0.001) pronounced effect was observed when it is combined balneotherapy and metabolic therapy. Analysis of ET-1 and ADMA at ST in conjunction with therapy and metabolic rate of sodium chloride baths there was a significant (P < 0.01) decrease in these parameters in comparison with those before treatment. In children with PAH have been identified violations of the functional activity of the endothelium, which is reflected in increased levels of ET-1, ADMA and reducing NO. Conducting rehabilitation inclusion complex balneotherapy and metabolic therapy helps to reduce average daily blood pressure, normalization of functional activity of the endothelium as a normalization of the synthesis of NO (P < 0.,001), a significant decrease of ET-1 (P < 0.01) and ADMA (P < 0.01).

  3. Real-time functional MRI using pseudo-continuous arterial spin labeling.

    PubMed

    Hernandez-Garcia, Luis; Jahanian, Hesamoddin; Greenwald, Mark K; Zubieta, Jon-Kar; Peltier, Scott J

    2011-06-01

    The first implementation of real-time acquisition and analysis of arterial spin labeling-based functional magnetic resonance imaging time series is presented in this article. The implementation uses a pseudo-continuous labeling scheme followed by a spiral k-space acquisition trajectory. Real-time reconstruction of the images, preprocessing, and regression analysis of the functional magnetic resonance imaging data were implemented on a laptop computer interfaced with the MRI scanner. The method allows the user to track the current raw data, subtraction images, and the cumulative t-statistic map overlaid on a cumulative subtraction image. The user is also able to track the time course of individual time courses and interactively selects a region of interest as a nuisance covariate. The pulse sequence allows the user to adjust acquisition and labeling parameters while observing their effect on the image within two successive pulse repetition times. This method is demonstrated by two functional imaging experiments: a simultaneous finger-tapping and visual stimulation paradigm, and a bimanual finger-tapping task.

  4. Angioplasty and stenting for severe vertebral artery orifice stenosis: effects on cerebellar function remodeling verified by blood oxygen level-dependent functional magnetic resonance imaging

    PubMed Central

    Liu, Bo; Li, Zhiwei; Xie, Peng

    2014-01-01

    Vertebral artery orifice stenting may improve blood supply of the posterior circulation of the brain to regions such as the cerebellum and brainstem. However, previous studies have mainly focused on recovery of cerebral blood flow and perfusion in the posterior circulation after interventional therapy. This study examined the effects of functional recovery of local brain tissue on cerebellar function remodeling using blood oxygen level-dependent functional magnetic resonance imaging before and after interventional therapy. A total of 40 Chinese patients with severe unilateral vertebral artery orifice stenosis were enrolled in this study. Patients were equally and randomly assigned to intervention and control groups. The control group received drug treatment only. The intervention group received vertebral artery orifice angioplasty and stenting + identical drug treatment to the control group. At 13 days after treatment, the Dizziness Handicap Inventory score was compared between the intervention and control groups. Cerebellar function remodeling was observed between the two groups using blood oxygen level-dependent functional magnetic resonance imaging. The improvement in dizziness handicap and cerebellar function was more obvious in the intervention group than in the control group. Interventional therapy for severe vertebral artery orifice stenosis may effectively promote cerebellar function remodeling and exert neuroprotective effects. PMID:25657727

  5. Testicular microlithiasis: Correlation with doppler sonography of testicular arteries and sperm function.

    PubMed

    Mahafza, Waleed S; Alarini, Mahmoud Y; Awadghanem, Ahmed F; Odwan, Ghazi; Juweid, Malik E

    2016-10-01

    To determine the prevalence of testicular microlithiasis and its correlation with Doppler parameters of testicular arteries and sperm function. Reports of 1,200 consecutive scrotal sonographic examinations performed at our hospital were reviewed. Patients diagnosed with testicular microlithiasis were recalled for detailed scrotal sonographic examination, including Doppler sonography and sperm function. The same examinations were performed in an age-matched control group and the findings compared. Testicular microlithiasis was found in 64 cases (5.3%). Doppler sonography showed mean resistance index, Vmax, and Vmin of 61.1 ± 9.3%, 18.2 ± 4.7 cm/s, and 7.7 ± 2.3 cm/s, respectively, in the testicular microlithiasis group versus 62.4 ± 10.4%, 18.4 ± 5.7 cm/s, and 7.3 ± 2.4 cm/s, respectively, in the control group (p = 0.49, 0.84 and 0.35, respectively). Sperm function tests demonstrated sperm count, motility, and normal morphology (normal oval head) of 29.6 ± 20.4 × 10(6) /mL, 35.3 ± 16.2%, and 44.4 ± 12%, respectively, in patients with testicular microlithiasis versus 54.3 ± 22.4 × 10(6) /mL, 50.2% ± 14.4%, and 66.4 ± 11.6% in control subjects (p < 0.02). Prevalence of testicular microlithiasis of 5.3% in Jordanian patients is similar to what has been reported in the literature. Testicular microlithiasis does not have a significant effect on Doppler parameters of testicular arteries. The apparent impairment of sperm function in patients with testicular microlithiasis warrants further studies. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:474-479, 2016. © 2016 Wiley Periodicals, Inc.

  6. Prediction of severe coronary artery disease using computerized ECG measurements and discriminant function analysis.

    PubMed

    Moussa, I; Rodriguez, M; Froning, J; Froelicher, V F

    1992-01-01

    This study tested the hypothesis that discriminant function analysis of clinical and exercise-test variables including computerized ST measurements could improve the prediction of severe coronary artery disease. Secondary objectives were to demonstrate the effect of digoxin and/or resting electrocardiographic (ECG) abnormalities, and to evaluate the relative importance of ST measurements made during the recovery phase and in the three lead group areas. The design was a retrospective analysis of data collected during exercise testing and coronary angiography. The ECG data were gathered and stored in digital format on optical discs and all ST measurements were made off-line using the authors' own software. Univariate and multivariate analytic methods were used to analyze all pretest characteristics as well as hemodynamic and computerized ECG responses to exercise. A 1,000-bed Veterans Affairs Medical Center served as the setting. The study included 446 male veterans who underwent a sign or symptom limited treadmill exercise test and coronary angiography. Analysis was also performed on a subset of this population formed by excluding patients receiving digoxin or with resting ECGs exhibiting left ventricular hypertrophy or ST depression (n = 328). In the total study population, the authors derived a treadmill score using discriminant function analysis. This score included: (1) the time-slope area in lead V5 during recovery; (2) delta heart rate; (3) angina pectoris during the exercise test; and (4) presence of diagnostic Q waves on the resting ECG. This score was effective in predicting triple vessel/left main disease and outperformed exercise-induced ST depression for predicting severe coronary artery disease. After exclusion of patients with ECGs exhibiting left ventricular hypertrophy or resting ST depression and patients receiving digoxin, discriminant function analysis chose: (1) the time-slope area in lead V5 during recovery and (2) delta heart rate. Exclusion of

  7. Coronary angioplasty and left ventricular function in single vessel coronary artery disease.

    PubMed

    Najm, Y C; Timmis, A D; Maisey, M N; Pinies, L M; Salinas, A; Curry, P V; Sowton, E

    1989-03-01

    Left ventricular function was investigated in 86 patients with single vessel coronary artery disease before and three to six months after successful angioplasty. Before angioplasty thallium-201 perfusion scintigraphy and technetium-99m gated equilibrium ventriculography in most patients showed that stress testing (exercise and ice water stimulation and isometric handgrip respectively) induced myocardial perfusion defects that were associated with a mean (SD) drop in left ventricular ejection fraction from 64 (6)% to 56 (7)%. After angioplasty there was residual coronary stenosis of less than or equal to 20% of the diameter of the vessel in 78 patients (group 1) and of between 20 and 50% in eight patients (group 2). After the procedure the perfusion defects seen during stress resolved in 86% of group 1 and in 87% of group 2. Despite the apparent improvement in myocardial perfusion left ventricular dysfunction persisted in group 2--that is during stress the left ventricular ejection fraction fell from 65% (6) to 56% (5). In group 1, on the other hand, the improvement in myocardial perfusion was associated with significant improvement in left ventricular function with a normal increase in ejection fraction from 63 (5) at rest to 67 (6) during stress. Radionuclide studies, one to six weeks after angioplasty in 30 group 1 patients showed continuing left ventricular decompensation during stress in nine (30%) of them despite correction of perfusion defects. But reinvestigation three to six months after the procedure showed recovery of left ventricular function with an increase in ejection fraction from 66 (5) at rest to 69 (7) during stress. These data indicate that coronary angioplasty procedures that give a residual stenosis of functional improvement may be delayed for up to three months, however, possibly because arterial healing at the angioplasty site is delayed. On the other

  8. Identification of neural firing patterns, frequency and temporal coding mechanisms in individual aortic baroreceptors

    PubMed Central

    Gu, Huaguang; Pan, Baobao

    2015-01-01

    In rabbit depressor nerve fibers, an on-off firing pattern, period-1 firing, and integer multiple firing with quiescent state were observed as the static pressure level was increased. A bursting pattern with bursts at the systolic phase of blood pressure, continuous firing, and bursting with burst at diastolic phase and quiescent state at systolic phase were observed as the mean level of the dynamic blood pressure was increased. For both static and dynamic pressures, the firing frequency of the first two firing patterns increased and of the last firing pattern decreased due to the quiescent state. If the quiescent state is disregarded, the spike frequency becomes an increasing trend. The instantaneous spike frequency of the systolic phase bursting, continuous firing, and diastolic phase bursting can reflect the temporal process of the systolic phase, whole procedure, and diastolic phase of the dynamic blood pressure signal, respectively. With increasing the static current corresponding to pressure level, the deterministic Hodgkin-Huxley (HH) model manifests a process from a resting state first to period-1 firing via a subcritical Hopf bifurcation and then to a resting state via a supercritical Hopf bifurcation, and the firing frequency increases. The on-off firing and integer multiple firing were here identified as noise-induced firing patterns near the subcritical and supercritical Hopf bifurcation points, respectively, using the stochastic HH model. The systolic phase bursting and diastolic phase bursting were identified as pressure-induced firings near the subcritical and supercritical Hopf bifurcation points, respectively, using an HH model with a dynamic signal. The firing, spike frequency, and instantaneous spike frequency observed in the experiment were simulated and explained using HH models. The results illustrate the dynamics of different firing patterns and the frequency and temporal coding mechanisms of aortic baroreceptor. PMID:26379539

  9. Static versus dynamic techniques for characterizing the carotid sinus baroreceptor reflex in conscious rabbits.

    PubMed

    Faris, I B; Jamieson, G G; Ludbrook, J

    1982-01-01

    1. We have studied in conscious rabbits the dynamic (AC) characteristics of the carotid sinus baroreceptor reflex by effecting sinusoidal pressure changes across the all of the carotid sinus of 28, 55 and 103 mmHg amplitude at frequencies of 0.005, 0.01 and 0.01 Hz. 2. The amplitudes of the reflex oscillations of blood pressure and heart rate were dependent on both input frequency and amplitude. The output amplitude for blood pressure was maximal at 0.005 Hz, for heart rate at 0.02 Hz: i.e. blood pressure output exhibited frequency attenuation, heart rate output frequency amplification. 3. AC gain was similarly dependent on input frequency, and was inversely associated, for both blood pressure and heart rate, with input amplitude. 4. Phase lag for heart rate behind carotid transmural pressure was small (3-4 degrees), suggesting that vagal efferent mechanisms predominated. For blood pressure it was positively associated with input frequency, and was much larger (30 degrees, 19 degrees and 12 degrees). 5. The reflex was also elicited by intermittent static (DC) input. The AC and DC output amplitudes were similar at high input amplitudes, but DC gain was always greater than AC except for the case of heart rate at high input frequency and low input amplitude. 6. The AC characteristics of the reflex were satisfactorily reproducible over 2-15 days. AC output amplitude provides a measure of the performance limits of the reflex, AC gain of its capacity to buffer rapidly changing disturbances, while phase lag reflects the inertia of the reflex.

  10. Zebrafish Sox7 and Sox18 function together to control arterial-venous identity.

    PubMed

    Pendeville, Hélène; Winandy, Marie; Manfroid, Isabelle; Nivelles, Olivier; Motte, Patrick; Pasque, Vincent; Peers, Bernard; Struman, Ingrid; Martial, Joseph A; Voz, Marianne L

    2008-05-15

    Sox7 and Sox18 are members of the F-subgroup of Sox transcription factors family and are mostly expressed in endothelial compartments. In humans, dominant mutations in Sox18 are the underlying cause of the severe hypotrichosis-lymphedema-telangiectasia disorder characterized by vascular defects. However little is known about which vasculogenic processes Sox7 and Sox18 regulate in vivo. We cloned the orthologs of Sox7 and Sox18 in zebrafish, analysed their expression pattern and performed functional analyses. Both genes are expressed in the lateral plate mesoderm during somitogenesis. At later stages, Sox18 is expressed in all axial vessels whereas Sox7 expression is mainly restricted to the dorsal aorta. Knockdown of Sox7 or Sox18 alone failed to reveal any phenotype. In contrast, blocking the two genes simultaneously led to embryos displaying dysmorphogenesis of the proximal aorta and arteriovenous shunts, all of which can account for the lack of circulation observed in the trunk and tail. Gene expression analyses performed with general endothelial markers on double morphants revealed that Sox7 and Sox18 are dispensable for the initial specification and positioning of the major trunk vessels. However, morphants display ectopic expression of the venous Flt4 marker in the dorsal aorta and a concomitant reduction of the artery-specific markers EphrinB2a and Gridlock. The striking similarities between the phenotype of Sox7/Sox18 morphants and Gridlock mutants strongly suggest that Sox7 and Sox18 control arterial-venous identity by regulating Gridlock expression.

  11. Polymeric stent materials dysregulate macrophage and endothelial cell functions: implications for coronary artery stent.

    PubMed

    Wang, Xintong; Zachman, Angela L; Chun, Young Wook; Shen, Fang-Wen; Hwang, Yu-Shik; Sung, Hak-Joon

    2014-07-01

    Biodegradable polymers have been applied as bulk or coating materials for coronary artery stents. The degradation of polymers, however, could induce endothelial dysfunction and aggravate neointimal formation. Here we use polymeric microparticles to simulate and demonstrate the effects of degraded stent materials on phagocytic activity, cell death and dysfunction of macrophages and endothelial cells. Microparticles made of low molecular weight polyesters were incubated with human macrophages and coronary artery endothelial cells (ECs). Microparticle-induced phagocytosis, cytotoxicity, apoptosis, cytokine release and surface marker expression were determined by immunostaining or ELISA. Elastase expression was analyzed by ELISA and the elastase-mediated polymer degradation was assessed by mass spectrometry. We demonstrated that poly(D,L-lactic acid) (PLLA) and polycaprolactone (PCL) microparticles induced cytotoxicity in macrophages and ECs, partially through cell apoptosis. The particle treatment alleviated EC phagocytosis, as opposed to macrophages, but enhanced the expression of vascular cell adhesion molecule (VCAM)-1 along with decreased nitric oxide production, indicating that ECs were activated and lost their capacity to maintain homeostasis. The activation of both cell types induced the release of elastase or elastase-like protease, which further accelerated polymer degradation. This study revealed that low molecule weight PLLA and PCL microparticles increased cytotoxicity and dysregulated endothelial cell function, which in turn enhanced elastase release and polymer degradation. These indicate that polymer or polymer-coated stents impose a risk of endothelial dysfunction after deployment which can potentially lead to delayed endothelialization, neointimal hyperplasia and late thrombosis. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  12. Functional analysis of the TRIB1 associated locus linked to plasma triglycerides and coronary artery disease.

    PubMed

    Douvris, Adrianna; Soubeyrand, Sébastien; Naing, Thet; Martinuk, Amy; Nikpay, Majid; Williams, Andrew; Buick, Julie; Yauk, Carole; McPherson, Ruth

    2014-06-03

    The TRIB1 locus has been linked to hepatic triglyceride metabolism in mice and to plasma triglycerides and coronary artery disease in humans. The lipid-associated single nucleotide polymorphisms (SNPs), identified by genome-wide association studies, are located ≈30 kb downstream from TRIB1, suggesting complex regulatory effects on genes or pathways relevant to hepatic triglyceride metabolism. The goal of this study was to investigate the functional relationship between common SNPs at the TRIB1 locus and plasma lipid traits. Characterization of the risk locus reveals that it encompasses a gene, TRIB1-associated locus (TRIBAL), composed of a well-conserved promoter region and an alternatively spliced transcript. Bioinformatic analysis and resequencing identified a single SNP, rs2001844, within the promoter region that associates with increased plasma triglycerides and reduced high-density lipoprotein cholesterol and coronary artery disease risk. Further, correction for triglycerides as a covariate indicated that the genome-wide association studies association is largely dependent on triglycerides. In addition, we show that rs2001844 is an expression trait locus (eQTL) for TRIB1 expression in blood and alters TRIBAL promoter activity in a reporter assay model. The TRIBAL transcript has features typical of long noncoding RNAs, including poor sequence conservation. Modulation of TRIBAL expression had limited impact on either TRIB1 or lipid regulatory genes mRNA levels in human hepatocyte models. In contrast, TRIB1 knockdown markedly increased TRIBAL expression in HepG2 cells and primary human hepatocytes. These studies demonstrate an interplay between a novel locus, TRIBAL, and TRIB1. TRIBAL is located in the genome-wide association studies identified risk locus, responds to altered expression of TRIB1, harbors a risk SNP that is an eQTL for TRIB1 expression, and associates with plasma triglyceride concentrations. © 2014 The Authors. Published on behalf of the

  13. The functional and structural changes in the basilar artery due to overpressure blast injury

    PubMed Central

    Toklu, Hale Z; Muller-Delp, Judy; Yang, Zhihui; Oktay, Şehkar; Sakarya, Yasemin; Strang, Kevin; Ghosh, Payal; Delp, Michael D; Scarpace, Philip J; Wang, Kevin KW; Tümer, Nihal

    2015-01-01

    Overpressure blast-wave induced brain injury (OBI) leads to progressive pathophysiologic changes resulting in a reduction in brain blood flow, blood brain barrier breakdown, edema, and cerebral ischemia. The aim of this study was to evaluate cerebral vascular function after single and repeated OBI. Male Sprague-Dawley rats were divided into three groups: Control (Naive), single OBI (30 psi peak pressure, 1 to 2 msec duration), and repeated (days 1, 4, and 7) OBI (r-OBI). Rats were killed 24 hours after injury and the basilar artery was isolated, cannulated, and pressurized (90 cm H2O). Vascular responses to potassium chloride (KCl) (30 to 100 mmol/L), endothelin-1 (10−12 to 10−7 mol/L), acetylcholine (ACh) (10−10 to 10−4 mol/L) and diethylamine-NONO-ate (DEA-NONO-ate) (10−10 to 10−4 mol/L) were evaluated. The OBI resulted in an increase in the contractile responses to endothelin and a decrease in the relaxant responses to ACh in both single and r-OBI groups. However, impaired DEA-NONO-ate-induced vasodilation and increased wall thickness to lumen ratio were observed only in the r-OBI group. The endothelin-1 type A (ETA) receptor and endothelial nitric oxide synthase (eNOS) immunoreactivity were significantly enhanced by OBI. These findings indicate that both single and r-OBI impairs cerebral vascular endothelium-dependent dilation, potentially a consequence of endothelial dysfunction and/or vascular remodelling in basilar arteries after OBI. PMID:26104291

  14. The functional and structural changes in the basilar artery due to overpressure blast injury.

    PubMed

    Toklu, Hale Z; Muller-Delp, Judy; Yang, Zhihui; Oktay, Şehkar; Sakarya, Yasemin; Strang, Kevin; Ghosh, Payal; Delp, Michael D; Scarpace, Philip J; Wang, Kevin K W; Tümer, Nihal

    2015-12-01

    Overpressure blast-wave induced brain injury (OBI) leads to progressive pathophysiologic changes resulting in a reduction in brain blood flow, blood brain barrier breakdown, edema, and cerebral ischemia. The aim of this study was to evaluate cerebral vascular function after single and repeated OBI. Male Sprague-Dawley rats were divided into three groups: Control (Naive), single OBI (30 psi peak pressure, 1 to 2 msec duration), and repeated (days 1, 4, and 7) OBI (r-OBI). Rats were killed 24 hours after injury and the basilar artery was isolated, cannulated, and pressurized (90 cm H2O). Vascular responses to potassium chloride (KCl) (30 to 100 mmol/L), endothelin-1 (10(-12) to 10(-7) mol/L), acetylcholine (ACh) (10(-10) to 10(-4) mol/L) and diethylamine-NONO-ate (DEA-NONO-ate) (10(-10) to 10(-4) mol/L) were evaluated. The OBI resulted in an increase in the contractile responses to endothelin and a decrease in the relaxant responses to ACh in both single and r-OBI groups. However, impaired DEA-NONO-ate-induced vasodilation and increased wall thickness to lumen ratio were observed only in the r-OBI group. The endothelin-1 type A (ET(A)) receptor and endothelial nitric oxide synthase (eNOS) immunoreactivity were significantly enhanced by OBI. These findings indicate that both single and r-OBI impairs cerebral vascular endothelium-dependent dilation, potentially a consequence of endothelial dysfunction and/or vascular remodelling in basilar arteries after OBI.

  15. Alterations in Perivascular Sympathetic and Nitrergic Innervation Function Induced by Late Pregnancy in Rat Mesenteric Arteries

    PubMed Central

    Caracuel, Laura; Callejo, María; Balfagón, Gloria

    2015-01-01

    Background and Purpose We investigated whether pregnancy was associated with changed function in components of perivascular mesenteric innervation and the mechanism/s involved. Experimental Approach We used superior mesenteric arteries from female Sprague-Dawley rats divided into two groups: control rats (in oestrous phase) and pregnant rats (20 days of pregnancy). Modifications in the vasoconstrictor response to electrical field stimulation (EFS) were analysed in the presence/absence of phentolamine (alpha-adrenoceptor antagonist) or L-NAME (nitric oxide synthase-NOS- non-specific inhibitor). Vasomotor responses to noradrenaline (NA), and to NO donor DEA-NO were studied, NA and NO release measured and neuronal NOS (nNOS) expression/activation analysed. Key Results EFS induced a lower frequency-dependent contraction in pregnant than in control rats. Phentolamine decreased EFS-induced vasoconstriction in segments from both experimental groups, but to a greater extent in control rats. EFS-induced vasoconstriction was increased by L-NAME in arteries from both experimental groups. This increase was greater in segments from pregnant rats. Pregnancy decreased NA release while increasing NO release. nNOS expression was not modified but nNOS activation was increased by pregnancy. Pregnancy decreased NA-induced vasoconstriction response and did not modify DEA-NO-induced vasodilation response. Conclusions and Implications Neural control of mesenteric vasomotor tone was altered by pregnancy. Diminished sympathetic and enhanced nitrergic components both contributed to the decreased vasoconstriction response to EFS during pregnancy. All these changes indicate the selective participation of sympathetic and nitrergic innervations in vascular adaptations produced during pregnancy. PMID:25951331

  16. Effects of melatonin and Pycnogenol on small artery structure and function in spontaneously hypertensive rats.

    PubMed

    Rezzani, Rita; Porteri, Enzo; De Ciuceis, Carolina; Bonomini, Francesca; Rodella, Luigi F; Paiardi, Silvia; Boari, Gianluca E M; Platto, Caterina; Pilu, Annamaria; Avanzi, Daniele; Rizzoni, Damiano; Agabiti Rosei, Enrico

    2010-06-01

    It was suggested that oxidative stress has a key role in the development of endothelial dysfunction, as well as microvascular structural alterations. Therefore, we have investigated 2 substances with antioxidant properties: melatonin and Pycnogenol. We treated 7 spontaneously hypertensive rats (SHRs) with melatonin and 7 with Pycnogenol for 6 weeks. We compared results obtained with those observed in 7 SHRs and 7 Wistar-Kyoto normotensive control rats kept untreated. Mesenteric small resistance arteries were dissected and mounted on a wire myograph, and a concentration-response curve to acetylcholine was performed. Aortic contents of metalloproteinase 2, Bax, inducible NO synthase, and cyclooxygenase 2 were evaluated, together with the aortic content of total collagen and collagen subtypes and apoptosis rate. A small reduction in systolic blood pressure was observed. A significant improvement in mesenteric small resistance artery structure and endothelial function was observed in rats treated with Pycnogenol and melatonin. Total aortic collagen content was significantly greater in untreated SHRs compared with Wistar-Kyoto control rats, whereas a full normalization was observed in treated rats. Apoptosis rate was increased in the aortas of untreated SHRs compared with Wistar-Kyoto control rats; an even more pronounced increase was observed in treated rats. Bax and metalloproteinase 2 expressions changed accordingly. Cyclooxygenase 2 and inducible NO synthase were more expressed in the aortas of untreated SHRs compared with Wistar-Kyoto control rats; this pattern was normalized by both treatments. In conclusion, our data suggest that treatment with Pycnogenol and melatonin may protect the vasculature, partly independent of blood pressure reduction, probably through their antioxidant effects.

  17. Association of lipoprotein subfractions with endothelial function and arterial stiffness in acute ischemic stroke.

    PubMed

    Šiarnik, Pavel; Čarnická, Zuzana; Krivošíková, Zuzana; Klobučníková, Katarína; Žitňanová, Ingrid; Kollár, Branislav; Sýkora, Marek; Turčáni, Peter

    2017-02-01

    Hypercholesterolemia represents a risk factor for the development of atherosclerosis. Lipoprotein research has recently been focused on the phenomenon of atherogenic and non-atherogenic lipoproteins. The aim of this study was to explore the association of lipoprotein subfractions with a measure for endothelial function (represented by reactive hyperemia index [RHI]) and arterial stiffness (represented by augmentation index [AI]) in patients with acute ischemic stroke. We enrolled 51 patients with acute ischemic stroke. Blood samples were obtained within 24 h after the stroke onset in a fasting condition. Electrophoresis method on polyacrylamide gel was used for the analysis of plasma lipoproteins. RHI and AI was measured by peripheral arterial tonometry (EndoPAT2000 device). We failed to find any significant correlation between RHI and baseline characteristics of the population. Significant correlation was found between AI and age, hypertension, low density lipoprotein cholesterol (LDL) 1, LDL 3-7, score for anti-atherogenic risk and atherogenic profile. Age (beta = .362, p = .006) and LDL1 (beta = -0.283, p = .031) were the only independent variables significantly associated with AI in regression analysis. Significantly higher AI was found in an atherogenic lipoprotein profile compared to a non-atherogenic profile population (median 25% vs. median 11.5%, p = .043). In conclusion, our results suggest significant inverse correlation between levels of LDL 1 subfraction and measures of AI in patients with acute ischemic stroke. Significantly higher values of AI were observed in the population with an atherogenic lipoprotein profile.

  18. TRPV1 channels in human skeletal muscle feed arteries: implications for vascular function.

    PubMed

    Ives, Stephen J; Park, Song Young; Kwon, Oh Sung; Gifford, Jayson R; Andtbacka, Robert H I; Hyngstrom, John R; Richardson, Russell S

    2017-09-01

    What is the central question of this study? We sought to determine whether human skeletal muscle feed arteries (SFMAs) express TRPV1 channels and what role they play in modulating vascular function. What is the main finding and its importance? Human SMFAs do express functional TRPV1 channels that modulate vascular function, specifically opposing α-adrenergic receptor-mediated vasocontraction and potentiating vasorelaxation, in an endothelium-dependent manner, as evidenced by the α1 -receptor-mediated responses. Thus, the vasodilatory role of TRPV1 channels, and their ligand capsaicin, could be a potential therapeutic target for improving vascular function. Additionally, given the 'sympatholytic' effect of TRPV1 activation and known endogenous activators (anandamide, reactive oxygen species, H(+) , etc.), TRPV1 channels might contribute to functional sympatholysis during exercise. To examine the role of the transient receptor potential vanilloid type 1 (TRPV1 ) ion channel in the vascular function of human skeletal muscle feed arteries (SMFAs) and whether activation of this heat-sensitive receptor could be involved in modulating vascular function, SMFAs from 16 humans (63 ± 5 years old, range 41-89 years) were studied using wire myography with capsaicin (TRPV1 agonist) and without (control). Specifically, phenylephrine (α1 -adrenergic receptor agonist), dexmedetomidine (α2 -adrenergic receptor agonist), ACh and sodium nitroprusside concentration-response curves were established to assess the role of TRPV1 channels in α-receptor-mediated vasocontraction as well as endothelium-dependent and -independent vasorelaxation, respectively. Compared with control conditions, capsaicin significantly attenuated maximal vasocontraction in response to phenylephrine [control, 52 ± 8% length-tensionmax (LTmax ) and capsaicin, 21 ± 5%LTmax ] and dexmedetomidine (control, 29 ± 12%LTmax and capsaicin, 2 ± 3%LTmax ), while robustly enhancing maximal vasorelaxation

  19. An Inquiry-Based Teaching Tool for Understanding Arterial Blood Pressure Regulation and Cardiovascular Function.

    ERIC Educational Resources Information Center

    Collins, Heidi L.; Rodenbaugh, David W.; Murphy, Todd P.; Kulics, Jennifer M.; Bailey, Cynthia M.; DiCarlo, Stephen E.

    1999-01-01

    Presents a laboratory exercise designed to introduce students to the hemodynamic variables (heart rate, stroke volume, total peripheral resistance, and compliance) that alter arterial pressure. (Author/CCM)

  20. An Inquiry-Based Teaching Tool for Understanding Arterial Blood Pressure Regulation and Cardiovascular Function.

    ERIC Educational Resources Information Center

    Collins, Heidi L.; Rodenbaugh, David W.; Murphy, Todd P.; Kulics, Jennifer M.; Bailey, Cynthia M.; DiCarlo, Stephen E.

    1999-01-01

    Presents a laboratory exercise designed to introduce students to the hemodynamic variables (heart rate, stroke volume, total peripheral resistance, and compliance) that alter arterial pressure. (Author/CCM)

  1. Comparing Arterial Function Parameters for the Prediction of Coronary Heart Disease Events: The Multi-Ethnic Study of Atherosclerosis (MESA).

    PubMed

    Hom, Elizabeth K; Duprez, Daniel A; Jacobs, David R; Bluemke, David A; Brumback, Lyndia C; Polak, Joseph F; Peralta, Carmen A; Greenland, Philip; Magzamen, Sheryl L; Lima, João A C; Redheuil, Alban; Herrington, David M; Stein, James H; Vaidya, Dhananjay; Ouyang, Pamela; Kaufman, Joel D

    2016-12-15

    Arterial dysfunction has been linked to decline in cardiac function and increased risk of cardiovascular disease events. We calculated the value of arterial function, measured at baseline (2000-2002), in predicting time to first coronary heart disease (CHD) event (median follow-up, 10.2 years) among participants in the Multi-Ethnic Study of Atherosclerosis (MESA). Measures included the following: C1 and C2, derived from diastolic pulse contour analysis from the radial artery blood pressure waveform obtained by tonometry (n = 6,336); carotid distensibility and Young's elastic modulus at the carotid artery, derived from carotid artery ultrasonography (n = 6,531 and 6,528); and aortic distensibility, measured using cardiac magnetic resonance imaging (n = 3,677). After adjustment, the hazard ratio for a CHD event per standard-deviation increment in arterial function was 0.97 (95% confidence interval (CI): 0.86, 1.10) for C1, 0.73 (95% CI: 0.63, 0.86) for C2, 0.98 (95% CI: 0.86, 1.11) for carotid distensibility, 0.99 (95% CI: 0.90, 1.09) for Young's modulus, and 0.90 (95% CI: 0.74, 1.10) for aortic distensibility. We examined the area under the receiver operating characteristic curve for the model with full adjustment plus the addition of each measure individually. C2 provided additional discrimination for the prediction of CHD (area under the curve = 0.736 vs. 0.743; P = 0.04). Lower C2 was associated with a higher risk of future CHD events.

  2. Analysis of the Baroreceptor and Vestibular Receptor Inputs in the Rostral Ventrolateral Medulla following Hypotension in Conscious Rats

    PubMed Central

    Lan, Yan; Lu, Huan-Jun; Jiang, Xian; Li, Li-Wei; Yang, Yan-Zhao; Jin, Guang-Shi; Park, Joo Young; Kim, Min Sun

    2015-01-01

    Input signals originating from baroreceptors and vestibular receptors are integrated in the rostral ventrolateral medulla (RVLM) to maintain blood pressure during postural movement. The contribution of baroreceptors and vestibular receptors in the maintenance of blood pressure following hypotension were quantitatively analyzed by measuring phosphorylated extracellular regulated protein kinase (pERK) expression and glutamate release in the RVLM. The expression of pERK and glutamate release in the RVLM were measured in conscious rats that had undergone bilateral labyrinthectomy (BL) and/or sinoaortic denervation (SAD) following hypotension induced by a sodium nitroprusside (SNP) infusion. The expression of pERK was significantly increased in the RVLM in the control group following SNP infusion, and expression peaked 10 min after SNP infusion. The number of pERK positive neurons increased following SNP infusion in BL, SAD, and BL+SAD groups, although the increase was smaller than seen in the control group. The SAD group showed a relatively higher reduction in pERK expression when compared with the BL group. The level of glutamate release was significantly increased in the RVLM in control, BL, SAD groups following SNP infusion, and this peaked 10 min after SNP infusion. The SAD group showed a relatively higher reduction in glutamate release when compared with the BL group. These results suggest that the baroreceptors are more powerful in pERK expression and glutamate release in the RVLM following hypotension than the vestibular receptors, but the vestibular receptors still have an important role in the RVLM. PMID:25729278

  3. Evaluation of Cardiac and Valvular Function after Arterial Switch Operation: A Midterm Follow-Up

    PubMed Central

    Amoozgar, Hamid; Salaminia, Shirvan; Amirghofran, Ahmad Ali; Cheriki, Sirous; Borzoee, Mohammad; Ajami, Gholamhossein; Peiravian, Farah

    2013-01-01

    Objectives Transposition of Great Arteries (TGA) is a serious congenital heart disease and anatomic correction in the first few weeks of life has revealed good outcomes nowadays. In this study, we aimed to evaluate the myocardial and valvular function at midterm postoperative follow-up. Patients and Methods In this study, thirty-three patients with TGA and Arterial Switch Operation (ASO) were evaluated by 2-dimensional, M-mode, Doppler, and pulsed Tissue Doppler. These patients were compared with 33 healthy children of the same age and gender as the normal control group. Student’s t-test and Pearson correlation were used to analyze the data. Besides, P<0.05 was considered as statistically significant. Results The mean follow up time was 40.9±5.6 months. Among the 33 patients with ASO, 6% had mild pulmonary stenosis, while 3% had mild pulmonary insufficiency. Aortic stenosis and aortic insufficiency of trivial to mild degree was seen in 12% and 12% of the patients, respectively. The patients’ systolic velocity of tricuspid (S), early diastolic velocity of tricuspid (Ea), and late velocity of tricuspid valve (Aa) were significantly different from those of the controls (P<0.001). Also, pulmonary annulus diameter was significantly dilated in the patients compared to the controls (1.67±0.41 vs. 1.29±0.28, P≤0.001). Besides, aortic annulus diameter (1.56±0.42 vs. 1.24±0.21, P=0.001) and also aortic sinus diameter (2.06±0.41 vs. 1.44±0.34, P=0.002) were significantly dilated, while sinutuboar junction diameter (1.65±0.5 vs. 1.28±0.29, P=0.094) was not dilated. Left ventricular function was in the normal range. Conclusions This study showed good left ventricular function, but some abnormalities in lateral tricuspid tissue Doppler velocities. Neoaortic and pulmonary diameters were significantly dilated, while aortic and pulmonary insufficiencies were clinically insignificant in most of the patients. Long-term follow-up is necessary in these patients. PMID

  4. Nitrotyrosine impairs mitochondrial function in fetal lamb pulmonary artery endothelial cells

    PubMed Central

    Wu, Tzong-Jin; Afolayan, Adeleye J.; Konduri, Girija G.

    2015-01-01

    Nitration of both protein-bound and free tyrosine by reactive nitrogen species results in the formation of nitrotyrosine (NT). We previously reported that free NT impairs microtubule polymerization and uncouples endothelial nitric oxide synthase (eNOS) function in pulmonary artery endothelial cells (PAEC). Because microtubules modulate mitochondrial function, we hypothesized that increased NT levels during inflammation and oxidative stress will lead to mitochondrial dysfunction in PAEC. PAEC isolated from fetal lambs were exposed to varying concentrations of free NT. At low concentrations (1–10 μM), NT increased nitration of mitochondrial electron transport chain (ETC) protein subunit complexes I–V and state III oxygen consumption. Higher concentrations of NT (50 μM) caused decreased microtubule acetylation, impaired eNOS interactions with mitochondria, and decreased ETC protein levels. We also observed increases in heat shock protein-90 nitration, mitochondrial superoxide formation, and fragmentation of mitochondria in PAEC. Our data suggest that free NT accumulation may impair microtubule polymerization and exacerbate reactive oxygen species-induced cell damage by causing mitochondrial dysfunction. PMID:26491046

  5. Facial mimetic, cosmetic, and functional standardized assessment of the facial artery musculomucosal (FAMM) flap.

    PubMed

    Jowett, Nathan; Hadlock, Tessa A; Sela, Eyal; Toth, Miklos; Knecht, Rainald; Lörincz, Balazs B

    2017-04-01

    To objectively assess donor site morbidity after harvesting the facial artery musculomucosal flap. Use of the FAMM-flap in oral cavity reconstruction remains sporadic. This case series describes our newly developed standardized assessment of this flap in a floor of mouth (FOM) reconstructive setting. Standardized postoperative assessment of the FAMM flap for donor site wound complications, functional, facial mimetic and oncologic outcomes. There were no wound complications. Oral competence remained intact, tongue mobility was good to excellent, average word articulation score was 98%, and mimetic function excellent in all patients. Three patients experienced ipsilateral upper lip anesthesia, and five patients were noted to have slight dysfunction of the orbicularis oris resulting in a loss of lip height at rest. The FAMM flap is a reliable option for reconstruction of ablative defects of the FOM, and should be considered a workhorse flap for oral cavity defects. Unlike the submental island flap, a complete level I dissection may be concurrently performed without compromising the vascular supply to the FAMM flap. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Impaired endothelial function in adolescents with overweight or obesity measured by peripheral artery tonometry.

    PubMed

    Pareyn, Aagje; Allegaert, Karel; Verhamme, Peter; Vinckx, Joseph; Casteels, Kristina

    2015-03-01

    Overweight and obesity in adolescents are associated with a subsequent increased mortality due to cardiovascular disease in adulthood. The reactive hyperemia-peripheral artery tonometry (RH-PAT) is a non-invasive method for endothelial function assessment. The goal of this study is to investigate endothelial function as assessed with the RH-PAT in adolescents with overweight or obesity. In 27 adolescents with overweight or obesity (16 males, 11 females) and 25 control subjects (12 males, 13 females) (age 12-20 yr) RH-PAT score and baseline pulse amplitude were measured after an overnight fast. Confounding risk factors for endothelial dysfunction, including smoking and diabetes mellitus were excluded. RH-PAT score was lower in adolescents with overweight or obesity compared to healthy controls, whereas their baseline pulse amplitude was higher (p = 0.027 and p < 0.0001, respectively). A significantly positive correlation was seen between baseline pulse amplitude and body mass index standard deviation score in the group with overweight or obese subjects. Endothelial dysfunction, measured by lower RH-PAT score and higher baseline pulse amplitude, was present in overweight adolescents. Interestingly, we also report for the first time in the literature a significant difference in baseline pulse amplitude between overweight adolescents compared to their peers. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Effect of mastication on functional recoveries after permanent middle cerebral artery occlusion in rats.

    PubMed

    Kawanishi, Katsuya; Koshino, Hisashi; Toyoshita, Yoshifumi; Tanaka, Maki; Hirai, Toshihiro

    2010-01-01

    We evaluated whether solid feed is more effective for functional recoveries than liquid feed in rats with ischemic brain injury after permanent middle cerebral artery occlusion (MCAO). A total of 36 male Wistar/ST rats were subjected to MCAO or sham surgery. After MCAO or sham surgery, all rats were provided liquid feed for 14 days. Then, all rats were divided into 3 groups: the solid feeding group, the liquid feeding group, and the solid feeding group of sham. Effect of mastication on functional recoveries after permanent MCAO in rats was evaluated by the limb placement test and Morris water maze (MWM) task. After surgery, limb placement test scores were equal in both MCAO groups. In the acquisition trials of MWM task, statistically significant differences in escape latency were observed between the liquid feeding group and sham groups at all days, and between the solid feeding group and sham groups at days 3 and 4 of the trials. In the probe trial, statistically significant differences in time spent were observed between the liquid feeding group and sham group. On day 5 of acquisition trials, the time spent in the periphery of the pool in MWM task was significantly different among the 3 groups. This study suggested that solid diet mastication could be effective for the rehabilitation of sensorimotor and learning/memory dysfunction induced by cerebral infarction. Copyright (c) 2010 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  8. Sex differences in vascular dysfunction and cardiovascular outcomes: The cardiac, endothelial function, and arterial stiffness in ESRD (CERES) study.

    PubMed

    Guajardo, Isabella; Ayer, Amrita; Johnson, Alexander D; Ganz, Peter; Mills, Claire; Donovan, Catherine; Scherzer, Rebecca; Shah, Sanjiv J; Peralta, Carmen A; Dubin, Ruth F

    2017-03-08

    Recent studies suggest that women with end-stage renal disease (ESRD) may have higher rates of mortality than men, but it is unknown whether sex differences in vascular function explain this disparity. The cardiac, endothelial function, and arterial stiffness in ESRD (CERES) study is an ongoing, prospective observational study designed to investigate vascular function, myocardial injury, and cardiovascular outcomes in ESRD. Among 200 CERES participants (34% women), we evaluated arterial wave reflections as augmentation index normalized to a heart rate of 75 (AIx75), arterial stiffness as pulse wave velocity, and macro- and microvascular endothelial dysfunction as flow-mediated dilation and velocity time integral (VTI). Over a median of 14 months, participants were followed for the composite outcome of cardiovascular hospitalization or all-cause death. Women had higher arterial wave reflection (Mean, SD AIx75 30% ± 9% for women vs. 21% ± 10% for men; P < 0.001) and worse microvascular function (VTI 55 ± 30 cm for women vs. 70 ± 27 cm for men; P = 0.007). After multivariable adjustment, female sex remained associated with a 0.5-SD higher AIx75 (95% CI [0.01, 0.9]) and 0.3-SD lower VTI (95%CI [0.1, 0.7]). Women experienced higher adjusted rates of the composite outcome (HR 2.5; 95%CI [1.1, 5.6]; P = 0.03), and further adjustment for arterial wave reflection attenuated this risk. Vascular dysfunction may partly explain the association of female sex with higher cardiovascular risk and mortality in patients with ESRD. Further studies are needed to explore whether sex differences in vascular function predict long-term outcomes, and whether hormonal or inflammatory factors explain these associations. © 2017 International Society for Hemodialysis.

  9. Effect of coronary artery bypass graft surgery on left ventricular systolic function

    PubMed Central

    Koene, Ryan J.; Kealhofer, Jessica V.; Adabag, Selcuk; Vakil, Kairav

    2017-01-01

    Background Changes in left ventricular (LV) systolic function in response to coronary artery bypass grafting (CABG) have not been fully assessed. Methods Between January 2001 and December 2014, 2,838 consecutive patients underwent isolated CABG at the Minneapolis Veterans Affairs Health Care System. Of these, 375 had echocardiographic assessment of LV function before (within 6 months) and after (3 to 24 months) CABG and were included in this analysis. Results While the mean LV ejection fraction (LVEF) did not change following CABG [(49±13)% vs. (49±12)%, P=0.51], LVEF decreased in the subgroup with normal (≥50%) pre-operative LVEF [from (59±5)% to (56±9)%, P<0.001] and improved in those with decreased (<50%) pre-operative LVEF [from (36±9)% to (41±12)%, P<0.001]. There was a significant reduction in LV internal diameter during end-diastole (LVIDd) (5.4±0.8 vs. 5.3±0.9, P=0.002) and an increase in left atrial diameter (LAD) (4.4±0.7 vs. 4.6±0.7, P<0.001). There were no perioperative changes in LV internal diameter during end-systole, LV mass, posterior wall thickness, or septal wall thickness. LVEF improved by >5% in 24% of the study population, did not change (+/− 5%) in 55%, and worsened by >5% in 21%. Patients with improved EF were less often diabetic and had lower pre-operative LVEF, and greater LV dimensions at baseline. Conclusions After CABG, there was a decrease in LVIDd and an increase in LAD. Also, a decrease in LV systolic function with CABG was observed in patients with normal pre-operative LVEF and an improvement in LV systolic function was observed in patients with decreased pre-operative LVEF. PMID:28275473

  10. Arterial blood gases, pulmonary function and pathology in rats exposed to 0. 75 or 1. 0 ppM ozone

    SciTech Connect

    Pepelko, W.E.; Mattox, J.K.; Yang, Y.Y.

    1980-06-01

    Arterial blood gases, residual lung volume (RV), deflation pressure volume (PV) curves, pulmonary pathology and body weight changes were studied in rats exposed up to 14 days to either 0.75 or 1.0 ppM ozone. Arterial PO2 and body weights decreased progressively with length of exposure while PaCO2 and RV increased. The slope of the PV curve decreased in all groups exposed to ozone. Pathological changes in the lung increased in severity with concentration and length of exposure. The present findings have shown that arterial blood gas measurements represent a sensitive index of altered lung function in rats, a species very sensitive to ozone exposure.

  11. [Brachial artery endothelial function in teenagers with obesity depending on severity of clinical, trophological and metabolic disorders].

    PubMed

    Maskova, G S; Chernaia, N L; Nagornova, E Iu; Fomina, O V; Byteva, T A

    2014-01-01

    We carried out complex examination of 68 adolescents aged 11-17 years with primary obesity which in addition to assessment of clinical-anamnestic, laboratory data and functional parameters of cardiovascular system included registration of reaction of brachial artery endothelium to reactive hyperemia. Vascular endothelial dysfunction (VED) was found in 66% of obese teenagers. Obesity in adolescents with VED was characterized by aggravated course with higher fat mass index (36.8 +/- 4.39%) and prevalence of hypothalamic (42%) and metabolic (8.8%) syndromes. Stable arterial hypertension (AH) found in 37% of examined adolescents was 1.5 times more often registered in those with VED. We distinguished 4 groups of adolescents with various degree of risk of development of cardiovascular disorders: with stable AH and VED (group I), with stable AH and normal function of vascular endothelium (group II), with normal or labile arterial pressure with VED (group III), with normal or labile arterial pressure with normal function of vascular endothelium. It is expedient to supplement examination of obese adolescents with assessment of the state of vascular endothelium aiming at determination of degree of risk of development of atherosclerosis and/or stable AH.

  12. Fibrinolytic system related to pulmonary arterial pressure and lung function of patients with idiopathic pulmonary fibrosis.

    PubMed

    Ban, Chengjun; Wang, Tongde; Zhang, Shu; Xin, Ping; Liang, Lirong; Wang, Chen; Dai, Huaping

    2017-09-01

    To investigate urokinase-(uPA) and tissue-type (tPA) plasminogen activator and plasminogen activator inhibitor type-1 (PAI-1) levels in patients with idiopathic pulmonary fibrosis (IPF) and to determine the relationship between fibrinolytic system and pulmonary arterial pressure and pulmonary function. Seventy-nine patients with IPF were included. Bronchoalveolar lavage fluid (BALF) and blood samples were collected. The concentrations of tPA, uPA and PAI-1 were measured using enzyme-linked immunosorbent assay. Doppler echocardiography was used to detect tricuspid regurgitation pressure gradient (TRPG) to estimate pulmonary arterial pressure. BALF tPA elevated (P < 0.005), circulatory PAI-1 decreased (P = 0.05) and the ratio of uPA and PAI-1 decreased (P = 0.01) in BALF in IPF patients with pulmonary hypertension (PH) compared to those without PH. Positive linear correlations were found: BALF tPA and TRPG (r = 0.558, P = 0.013); the predicted percentage of diffusion capacity of lung for carbon monoxide adjustments for alveolar volume and BALF uPA (r = 0.319, P = 0.035). Negative linear correlations were as follows: BALF PAI-1 and the predicted percentage of VCmax (r = -0.325, P = 0.020), or total lung capacity (r = -0.312, P = 0.033); circulatory PAI-1 and TRPG (r = -0.697, P = 0.003). The change of alveolar fibrolytic system in IPF, especially the uPA reduction and the PAI-1elevation, contributes to the deterioration of lung function. During the lung injury initiating fibrosis, tPA and PAI-1 might be leaked out of the pulmonary capillaries into alveoli, resulting in their elevation in alveoli and reduction in circulation, and finally contributing to the development of PH in IPF. © 2015 John Wiley & Sons Ltd.

  13. Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans

    NASA Technical Reports Server (NTRS)

    Wilson, T. E.; Cui, J.; Crandall, C. G.

    2001-01-01

    1. Prior findings suggest that baroreflexes are capable of modulating skin blood flow, but the effects of baroreceptor loading/unloading on sweating are less clear. Therefore, this project tested the hypothesis that pharmacologically induced alterations in arterial blood pressure in heated humans would lead to baroreflex-mediated changes in both skin sympathetic nerve activity (SSNA) and sweat rate. 2. In seven subjects mean arterial blood pressure was lowered (approximately 8 mmHg) and then raised (approximately 13 mmHg) by bolus injections of sodium nitroprusside and phenylephrine, respectively. Moreover, in a separate protocol, arterial blood pressure was reduced via steady-state administration of sodium nitroprusside. In both normothermia and heat-stress conditions the following responses were monitored: sublingual and mean skin temperatures, heart rate, beat-by-beat blood pressure, skin blood flow (laser-Doppler flowmetry), local sweat rate and SSNA (microneurography from peroneal nerve). 3. Whole-body heating increased skin and sublingual temperatures, heart rate, cutaneous blood flow, sweat rate and SSNA, but did not change arterial blood pressure. Heart rate was significantly elevated (from 74 +/- 3 to 92 +/- 4 beats x min(-1); P < 0.001) during bolus sodium nitroprusside-induced reductions in blood pressure, and significantly reduced (from 92 +/- 4 to 68 +/- 4 beats x min(-1); P < 0.001) during bolus phenylephrine-induced elevations in blood pressure, thereby demonstrating normal baroreflex function in these subjects. 4. Neither SSNA nor sweat rate was altered by rapid (bolus infusion) or sustained (steady-state infusion) changes in blood pressure regardless of the thermal condition. 5. These data suggest that SSNA and sweat rate are not modulated by arterial baroreflexes in normothermic or moderately heated individuals.

  14. Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans

    PubMed Central

    Wilson, Thad E; Cui, Jian; Crandall, Craig G

    2001-01-01

    Prior findings suggest that baroreflexes are capable of modulating skin blood flow, but the effects of baroreceptor loading/unloading on sweating are less clear. Therefore, this project tested the hypothesis that pharmacologically induced alterations in arterial blood pressure in heated humans would lead to baroreflex-mediated changes in both skin sympathetic nerve activity (SSNA) and sweat rate. In seven subjects mean arterial blood pressure was lowered (≈8 mmHg) and then raised (≈13 mmHg) by bolus injections of sodium nitroprusside and phenylephrine, respectively. Moreover, in a separate protocol, arterial blood pressure was reduced via steady-state administration of sodium nitroprusside. In both normothermia and heat-stress conditions the following responses were monitored: sublingual and mean skin temperatures, heart rate, beat-by-beat blood pressure, skin blood flow (laser-Doppler flowmetry), local sweat rate and SSNA (microneurography from peroneal nerve). Whole-body heating increased skin and sublingual temperatures, heart rate, cutaneous blood flow, sweat rate and SSNA, but did not change arterial blood pressure. Heart rate was significantly elevated (from 74 ± 3 to 92 ± 4 beats min−1; P < 0.001) during bolus sodium nitroprusside-induced reductions in blood pressure, and significantly reduced (from 92 ± 4 to 68 ± 4 beats min−1; P < 0.001) during bolus phenylephrine-induced elevations in blood pressure, thereby demonstrating normal baroreflex function in these subjects. Neither SSNA nor sweat rate was altered by rapid (bolus infusion) or sustained (steady-state infusion) changes in blood pressure regardless of the thermal condition. These data suggest that SSNA and sweat rate are not modulated by arterial baroreflexes in normothermic or moderately heated individuals. PMID:11600694

  15. Absence of arterial baroreflex modulation of skin sympathetic activity and sweat rate during whole-body heating in humans

    NASA Technical Reports Server (NTRS)

    Wilson, T. E.; Cui, J.; Crandall, C. G.

    2001-01-01

    1. Prior findings suggest that baroreflexes are capable of modulating skin blood flow, but the effects of baroreceptor loading/unloading on sweating are less clear. Therefore, this project tested the hypothesis that pharmacologically induced alterations in arterial blood pressure in heated humans would lead to baroreflex-mediated changes in both skin sympathetic nerve activity (SSNA) and sweat rate. 2. In seven subjects mean arterial blood pressure was lowered (approximately 8 mmHg) and then raised (approximately 13 mmHg) by bolus injections of sodium nitroprusside and phenylephrine, respectively. Moreover, in a separate protocol, arterial blood pressure was reduced via steady-state administration of sodium nitroprusside. In both normothermia and heat-stress conditions the following responses were monitored: sublingual and mean skin temperatures, heart rate, beat-by-beat blood pressure, skin blood flow (laser-Doppler flowmetry), local sweat rate and SSNA (microneurography from peroneal nerve). 3. Whole-body heating increased skin and sublingual temperatures, heart rate, cutaneous blood flow, sweat rate and SSNA, but did not change arterial blood pressure. Heart rate was significantly elevated (from 74 +/- 3 to 92 +/- 4 beats x min(-1); P < 0.001) during bolus sodium nitroprusside-induced reductions in blood pressure, and significantly reduced (from 92 +/- 4 to 68 +/- 4 beats x min(-1); P < 0.001) during bolus phenylephrine-induced elevations in blood pressure, thereby demonstrating normal baroreflex function in these subjects. 4. Neither SSNA nor sweat rate was altered by rapid (bolus infusion) or sustained (steady-state infusion) changes in blood pressure regardless of the thermal condition. 5. These data suggest that SSNA and sweat rate are not modulated by arterial baroreflexes in normothermic or moderately heated individuals.

  16. Partial baroreceptor dysfunction and low plasma nitric oxide bioavailability as determinants of salt-sensitive hypertension: a reverse translational rat study

    PubMed Central

    Rodríguez-Pérez, A.S.; López-Rodríguez, J.F.; Calvo-Turrubiartes, M.Z.; Saavedra-Alanís, V.M.; Llamazares-Azuara, L.; Rodríguez-Martínez, M.

    2013-01-01

    This study determined whether clinical salt-sensitive hypertension (cSSHT) results from the interaction between partial arterial baroreceptor impairment and a high-sodium (HNa) diet. In three series (S-I, S-II, S-III), mean arterial pressure (MAP) of conscious male Wistar ChR003 rats was measured once before (pdMAP) and twice after either sham (SHM) or bilateral aortic denervation (AD), following 7 days on a low-sodium (LNa) diet (LNaMAP) and then 21 days on a HNa diet (HNaMAP). The roles of plasma nitric oxide bioavailability (pNOB), renal medullary superoxide anion production (RMSAP), and mRNA expression of NAD(P)H oxidase and superoxide dismutase were also assessed. In SHM (n=11) and AD (n=15) groups of S-I, LNaMAP-pdMAP was 10.5±2.1 vs 23±2.1 mmHg (P<0.001), and the salt-sensitivity index (SSi; HNaMAP−LNaMAP) was 6.0±1.9 vs 12.7±1.9 mmHg (P=0.03), respectively. In the SHM group, all rats were normotensive, and 36% were salt sensitive (SSi≥10 mmHg), whereas in the AD group ∼50% showed cSSHT. A 45% reduction in pNOB (P≤0.004) was observed in both groups in dietary transit. RMSAP increased in the AD group on both diets but more so on the HNa diet (S-II, P<0.03) than on the LNa diet (S-III, P<0.04). MAP modeling in rats without a renal hypertensive genotype indicated that the AD*HNa diet interaction (P=0.008) increases the likelihood of developing cSSHT. Translationally, these findings help to explain why subjects with clinical salt-sensitive normotension may transition to cSSHT. PMID:24141614

  17. The effect of regular physical activity on the left ventricle systolic function in patients with chronic coronary artery disease.

    PubMed

    Panovský, R; Kukla, P; Jančár, R; Meluzín, J; Jančík, J; Kincl, V; Poloková, K; Mífková, L; Havelková, A; Látalová, R; Dobšák, P; Pešl, M

    2011-01-01

    The purpose of this study was to assess the influence of aerobic training on the left ventricular (LV) systolic function. Thirty patients with stable coronary artery disease, who had participated in the conducted 3-month physical training, were retrospectively divided into 2 cohorts. While patients in the cohort I (n=14) had continued training individually for 12 months, patients in the cohort II (n=16) had stopped training after finishing the conducted program. Rest and stress dobutamine/atropine echocardiography was performed in all patients before the training program and 1 year later. The peak systolic velocities of mitral annulus (Sa) were assessed by tissue Doppler imaging for individual LV walls. In addition, to determine global LV systolic longitudinal function, the four-site mean systolic velocity was calculated (Sa glob). According to the blood supply, left ventricular walls were divided into 5 groups: A- walls supplied by nonstenotic artery; B- walls supplied by coronary artery with stenosis ≤50 %; C- walls supplied by coronary artery with stenosis 51-70 %; D- walls with stenosis of supplying artery 71-99 %; and E- walls with totally occluded supplying artery. In global systolic function, the follow-up values of Sa glob in cohort I were improved by 0.23±0.36 as compared with baseline values at rest, and by 1.26±0.65 cm/s at the maximal load, while the values of Sa glob in cohort II were diminished by 0.53±0.22 (p=NS), and by 1.25±0.45 cm/s (p<0.05), respectively. Concerning the resting regional function, the only significant difference between cohorts in follow-up changes was found in walls E: 0.37±0.60 versus -1.76±0.40 cm/s (p<0.05). At the maximal load, the significant difference was found only in walls A (0.16±0.84 versus -2.67±0.87 cm/s; p<0.05). Patients with regular 12-month physical activity improved their global left ventricle systolic function mainly due to improvement of contractility in walls supplied by a totally occluded coronary

  18. Daily short-period gravitation can prevent functional and structural changes in arteries of simulated microgravity rats.

    PubMed

    Sun, Biao; Zhang, Li-Fan; Gao, Fang; Ma, Xiao-Wu; Zhang, Miao-Li; Liu, Jian; Zhang, Le-Ning; Ma, Jin

    2004-09-01

    This study was designed to clarify whether simulated microgravity-induced differential adaptational changes in cerebral and hindlimb arteries could be prevented by daily short-period restoration of the normal distribution of transmural pressure across arterial vasculature by either dorsoventral or footward gravitational loading. Tail suspension (Sus) for 28 days was used to simulate cardiovascular deconditioning due to microgravity. Daily standing (STD) for 1, 2, or 4 h, or +45 degrees head-up tilt (HUT) for 2 or 4 h was used to provide short-period dorsoventral or footward gravitational loading as countermeasure. Functional studies showed that Sus alone induced an enhancement and depression in vasoconstrictor responsiveness of basilar and femoral arterial rings, respectively, as previously reported. These differential functional alterations can be prevented by either of the two kinds of daily gravitational loading treatments. Surprisingly, daily STD for as short as 1 h was sufficient to prevent the differential functional changes that might occur due to Sus alone. In morphological studies, the effectiveness of daily 4-h HUT or 1-h STD in preventing the differential remodeling changes in the structure of basilar and anterior tibial arteries induced by Sus alone was examined by histomorphometry. The results showed that both the hypertrophic and atrophic changes that might occur, respectively, in cerebral and hindlimb arteries due to Sus alone were prevented not only by daily HUT for 4 h but also by daily STD even for 1 h. These data indicate that daily gravitational loading by STD for as short as 1 h is sufficient to prevent differential adaptational changes in function and structure of vessels in different anatomic regions induced by a medium-term simulated microgravity.

  19. Association between arterial stiffness, disease activity and functional impairment in ankylosing spondylitis patients: a cross-sectional study.

    PubMed

    Avram, Claudiu; Drăgoi, Răzvan Gabriel; Popoviciu, Horațiu; Drăgoi, Mihai; Avram, Adina; Amaricăi, Elena

    2016-08-01

    Cardiovascular risk is an important factor for increased morbidity and mortality in patients with ankylosing spondylitis. The aim of this study is to assess arterial stiffness in relation to the disease activity and functional limitation in patients with ankylosing spondylitis. Twenty-four patients (mean age 45.8 ± 11.7 years) suffering of ankylosing spondylitis (disease duration 11.1 ± 5.1 years) and 24 gender and age-matched healthy controls were included in the study. Clinical, biological, and functional status of ankylosing spondylitis patients was recorded. Arterial stiffness was assessed by measuring pulse wave velocity (PWV) and pulse wave analysis (PWA) was performed using applanation tonometry. We found significant differences between ankylosing spondylitis patients and healthy controls in regard to PWV (p = 0.047), aortic augmentation pressure-AP (p = 0.028), augmentation index-AIx (p = 0.038) and aortic augmentation index adjusted for heart rate-AIx75 (p = 0.011). PWV and AIx75 were significantly associated with the disease functioning score-BASFI (p = 0.012, r = 0.504; p = 0.041, r = 0.421). Aortic AP and augmentation indexes (AIx and AIx75) were all associated to ASDAS score (p = 0.028, r = 0.448; p = 0.005, r = 0.549; p = 0.025, r = 0.455). Our study showed that ankylosing spondylitis patients have a higher arterial stiffness than the age-matched controls, leading to an increased cardiovascular risk. We found that arterial stiffness is positively associated with disease activity and functional impairment. Chronic spondiloarthropaties should be screened for arterial stiffness, even in the absence of traditional cardiovascular risk factors, in order to benefit from primary prevention measures.

  20. Assessment of left ventricular function long term after arterial switch operation for transposition of the great arteries by dobutamine stress echocardiography.

    PubMed

    Hui, L; Chau, A K T; Leung, M P; Chiu, C S W; Cheung, Y F

    2005-01-01

    To use dobutamine stress echocardiography to determine left ventricular (LV) function and wall motion of children long term after arterial switch operation (ASO) for transposition of the great arteries. 31 patients (24 boys) with ASO performed at a mean (SD) of 15.5 (4.3) days of life were studied at an age of 9.4 (2.0) years. All had normal coronary angiographic findings. LV echocardiographic indexes, including fractional shortening, ejection fraction, rate corrected velocity of circumferential fibre shortening (VCFc), and wall stress, as well as LV wall motion abnormalities were determined at rest and under dobutamine stress. The results were compared with those of 20 healthy age matched control participants. Tertiary paediatric cardiac centre. Fractional shortening, ejection fraction, and VCFc were significantly lower in patients than in controls at rest (all with p < 0.001). Stress-velocity index detected impaired LV contractility in 19 (61%) patients at rest. An older age at operation (p = 0.01), longer bypass (p = 0.01) and circulatory arrest times (p = 0.045), and an unusual coronary artery pattern (p = 0.059) were associated with impaired resting LV contractility. Dobutamine stress echocardiography unmasked wall motion abnormalities in 23 (74%) patients. Exercise myocardial perfusion scan, performed in 22 patients, showed reversible myocardial perfusion defects in 17. These defects corresponded to segments of hypokinesia as detected by dobutamine stress echocardiography. A significant proportion of children, albeit asymptomatic, had impaired baseline LV contractility and reversible myocardial perfusion defects and mild wall motion abnormalities on stress after ASO.

  1. Influence of various therapeutic strategies on right ventricular morphology, function and hemodynamics in pulmonary arterial hypertension.

    PubMed

    Badagliacca, Roberto; Raina, Amresh; Ghio, Stefano; D'Alto, Michele; Confalonieri, Marco; Correale, Michele; Corda, Marco; Paciocco, Giuseppe; Lombardi, Carlo; Mulè, Massimiliano; Poscia, Roberto; Scelsi, Laura; Argiento, Paola; Sciomer, Susanna; Benza, Raymond L; Vizza, Carmine Dario

    2017-08-26

    In idiopathic pulmonary arterial hypertension (IPAH) treatment goals include improving right ventricular (RV) function, hemodynamics and symptoms to move patients to a low-risk category for adverse clinical outcomes. No data are available on the effect of upfront combination therapy on RV improvement as compared with monotherapy. The aim of this study was to evaluate echocardiographic RV morphology and function in patients affected by IPAH and treated with different strategies. Sixty-nine consecutive, treatment-naive IPAH patients treated with first-line upfront combination therapy at 10 centers were retrospectively evaluated and compared with 2 matched cohorts treated with monotherapy after short-term follow-up. Evaluation included clinical, hemodynamic and echocardiographic parameters. At 155 ± 65 days after baseline evaluation, patients in the oral+prostanoid group (Group 1) had the most clinical and hemodynamic improvement compared with the double oral group (Group 2), the oral monotherapy group (Group 3) and the prostanoid monotherapy group (Group 4). The more extensive reduction of pulmonary vascular resistance in Groups 1, 2 and 4 was associated with significant improvement in all RV echocardiographic parameters compared with Group 3. Considering the number of patients who reached the target goals suggested by established guidelines, 8 of 27 (29.6%) and 7 of 42 (16.7%) patients in Groups 1 and 2, respectively, achieved low-risk status, as compared with 2 of 69 (2.8%) and 6 of 27 (22.2%) in Groups 3 and 4, respectively. In advanced treatment-naive IPAH patients, an upfront combination therapy strategy seems to significantly improve hemodynamics and RV morphology and function compared with oral monotherapy. The most significant results seem to be achieved with prostanoids plus oral drug, whereas the use of the double oral combination and prostanoids as monotherapy seem to produce similar results. Copyright © 2017 International Society for the Heart and Lung

  2. Mildronate treatment improves functional recovery following middle cerebral artery occlusion in rats.

    PubMed

    Svalbe, Baiba; Zvejniece, Liga; Vavers, Edijs; Pugovics, Osvalds; Muceniece, Ruta; Liepinsh, Edgars; Dambrova, Maija

    2011-09-12

    Mildronate (3-(2,2,2-trimethylhydrazinium) propionate) is an inhibitor of l-carnitine biosynthesis and an anti-ischemic drug. In the present study, we investigated the effects of mildronate in rats following focal cerebral ischemia. Male Wistar rats were subjected to transient occlusion of the middle cerebral artery (MCAO) for 90min, followed by the intraperitoneal administration of mildronate at doses of 100 and 200mg/kg 2h after reperfusion and then daily for an additional 14days. The beam-walking, rota-rod and cylinder tests were used to assess sensorimotor function, and vibrissae-evoked forelimb-placing and limb-placing tests examined responses to tactile and proprioceptive stimulation. Following behavioural testing, the infarct volume was measured. The cerebellar concentrations of l-carnitine, γ-butyrobetaine (GBB) and mildronate were also measured. The results showed that saline-treated MCAO rats had minor or no spontaneous recovery in sensorimotor and proprioceptive function up to 14days post-stroke. Treatment with mildronate at a dose of 200mg/kg was found to accelerate recovery of motor and proprioceptive deficits in limb-placing, cylinder and beam-walking tests. Analysis of rat cerebellar tissue extracts revealed that l-carnitine and GBB concentrations changed with mildronate treatment; the concentration of l-carnitine was significantly decreased by mildronate treatment, whereas the concentration of GBB was significantly increased. Cerebellar concentrations of mildronate also increased in a dose-dependent manner following systemic administration. Infarct size did not differ among the experimental groups on post-stroke day 14. The present study suggests that mildronate treatment improves the functional outcome in MCAO rats without influencing infarct size.

  3. Effects of low and high doses of fosinopril on the structure and function of resistance arteries.

    PubMed

    Rizzoni, D; Castellano, M; Porteri, E; Bettoni, G; Muiesan, M L; Cinelli, A; Rosei, E A

    1995-07-01

    It has been suggested that angiotensin-converting enzyme inhibitors may induce a significant regression of cardiovascular hypertrophy not only through blood pressure reduction but also as a possible consequence of growth factor inhibition. The aim of this study was to evaluate the effects of the angiotensin-converting enzyme inhibitor fosinopril, given either at a hypotensive high dose or a nonhypotensive low dose, on structural and functional alterations of mesenteric resistance arteries and on cardiac mass in spontaneously hypertensive rats (SHR) and control Wistar-Kyoto rats. Fosinopril was administered in the drinking water from 6 to 12 weeks of age. Rats were killed at 12 weeks, and the ratio of heart weight to body weight was measured. Mesenteric arterioles were dissected and mounted on a micromyograph (Mulvany's technique). Vascular morphology (media-lumen ratio, media thickness) and endothelial function (response to acetylcholine) were then assessed. During the 6 weeks of treatment, systolic pressure in SHR treated with high-dose fosinopril was significantly lower compared with that in untreated SHR, whereas no difference was observed with low-dose fosinopril. In SHR treated with both high-dose and low-dose fosinopril, a statistically significant reduction of vascular structural alterations, in terms of both media-lumen ratio and media thickness, was observed. The ratio of heart weight to body weight was reduced only in SHR treated with high-dose fosinopril. An improvement in the endothelium-dependent relaxation to acetylcholine was observed in SHR treated with high-dose fosinopril compared with untreated SHR, whereas in SHR treated with low-dose fosinopril no improvement in endothelial function was detected.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Decompressive craniectomy for malignant middle cerebral artery infarction: Impact on mortality and functional outcome

    PubMed Central

    Raffiq, Mohammad Azman Mohammed; Haspani, Mohammed Saffari Mohammad; Kandasamy, Regunath; Abdullah, Jafri Malin

    2014-01-01

    Background: Malignant middle cerebral artery (MCA) infarction is a devastating clinical entity affecting about 10% of stroke patients. Decompressive craniectomy has been found to reduce mortality rates and improve outcome in patients. Methods: A retrospective case review study was conducted to compare patients treated with medical therapy and decompressive surgery for malignant MCA infarction in Hospital Kuala Lumpur over a period of 5 years (from January 2007 to December 2012). A total of 125 patients were included in this study; 90 (72%) patients were treated with surgery, while 35 (28%) patients were treated with medical therapy. Outcome was assessed in terms of mortality rate at 30 days, Glasgow Outcome Score (GOS) on discharge, and modified Rankin scale (mRS) at 3 and 6 months. Results: Decompressive craniectomy resulted in a significant reduction in mortality rate at 30 days (P < 0.05) and favorable GOS outcome at discharge (P < 0.05). Good functional outcome based on mRS was seen in 48.9% of patients at 3 months and in 64.4% of patients at 6 months (P < 0.05). Factors associated with good outcome include infarct volume of less than 250 ml, midline shift of less than 10 mm, absence of additional vascular territory involvement, good preoperative Glasgow Coma Scale (GCS) score, and early surgical intervention (within 24 h) (P < 0.05). Age and dominant hemisphere infarction had no significant association with functional outcome. Conclusion: Decompressive craniectomy achieves good functional outcome in, young patients with good preoperative GCS score and favorable radiological findings treated with surgery within 24 h of ictus. PMID:25101197

  5. Galectin-3 levels are associated with right ventricular functional and morphologic changes in pulmonary arterial hypertension.

    PubMed

    Fenster, Brett E; Lasalvia, Luis; Schroeder, Joyce D; Smyser, Jamey; Silveira, Lori J; Buckner, J Kern; Brown, Kevin K

    2016-06-01

    The response of the right ventricle (RV) to pulmonary arterial hypertension (PAH) involves changes in contractile function, chamber size, hypertrophy, and extracellular matrix (ECM). Galectin-3 (Gal-3) is a mediator of myocardial ECM metabolism and biomarker for left heart remodeling, yet its ability to reflect RV remodeling is unknown. We hypothesized that serum Gal-3 levels correlate with RV morphology and function in PAH, and that Gal-3 is associated with circulating markers of ECM. Fifteen subjects with PAH and 10 age-matched controls underwent same-day echocardiography, cardiac magnetic resonance (CMR) imaging, and phlebotomy for Gal-3 and ECM biomarkers including N-terminal propeptide of type III collagen type (PIIINP), tissue inhibitor of metalloproteinase-1 (TIMP-1), and hyaluronic acid (HA). RV ejection fraction, end diastolic volume index, end systolic volume index, and mass index were calculated using CMR. Echocardiography was used to estimate RV systolic pressure and measure RV strain. Serum Gal-3, TIMP-1, and HA levels were all significantly increased in PAH subjects when compared to controls. Gal-3 correlated with RV ejection fraction (ρ -0.44, p 0.03), end diastolic volume index (ρ 0.42, p 0.03), end systolic volume index (ρ 0.44, p 0.027), mass index (ρ 0.47, p 0.016), systolic pressure (ρ 0.55, p < 0.001), and strain (ρ 0.43, p 0.03). Gal-3 levels positively correlated with the ECM markers TIMP-1 and HA but not with PIIINP. In conclusion, Gal-3 levels are associated with multiple indices of RV function and morphology. Gal-3 may represent a novel biomarker for RV remodeling and associated ECM turnover in PAH.

  6. Arterial spin labelling shows functional depression of non-lesion tissue in chronic Wernicke's aphasia.

    PubMed

    Robson, Holly; Specht, Karsten; Beaumont, Helen; Parkes, Laura M; Sage, Karen; Lambon Ralph, Matthew A; Zahn, Roland

    2017-07-01

    Behavioural impairment post-stroke is a consequence of structural damage and altered functional network dynamics. Hypoperfusion of intact neural tissue is frequently observed in acute stroke, indicating reduced functional capacity of regions outside the lesion. However, cerebral blood flow (CBF) is rarely investigated in chronic stroke. This study investigated CBF in individuals with chronic Wernicke's aphasia (WA) and examined the relationship between lesion, CBF and neuropsychological impairment. Arterial spin labelling CBF imaging and structural MRIs were collected in 12 individuals with chronic WA and 13 age-matched control participants. Joint independent component analysis (jICA) investigated the relationship between structural lesion and hypoperfusion. Partial correlations explored the relationship between lesion, hypoperfusion and language measures. Joint ICA revealed significant differences between the control and WA groups reflecting a large area of structural lesion in the left posterior hemisphere and an associated area of hypoperfusion extending into grey matter surrounding the lesion. Small regions of remote cortical hypoperfusion were observed, ipsilateral and contralateral to the lesion. Significant correlations were observed between the neuropsychological measures (naming, repetition, reading and semantic association) and the jICA component of interest in the WA group. Additional ROI analyses found a relationship between perfusion surrounding the core lesion and the same neuropsychological measures. This study found that core language impairments in chronic WA are associated with a combination of structural lesion and abnormal perfusion in non-lesioned tissue. This indicates that post-stroke impairments are due to a wider disruption of neural function than observable on structural T1w MRI. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Impaired Cerebrovascular Function in Coronary Artery Disease Patients and Recovery Following Cardiac Rehabilitation

    PubMed Central

    Anazodo, Udunna C.; Shoemaker, J. K.; Suskin, Neville; Ssali, Tracy; Wang, Danny J. J.; St. Lawrence, Keith S.

    2016-01-01

    Coronary artery disease (CAD) poses a risk to the cerebrovascular function of older adults and has been linked to impaired cognitive abilities. Using magnetic resonance perfusion imaging, we investigated changes in resting cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to hypercapnia in 34 CAD patients and 21 age-matched controls. Gray matter volume (GMV) images were acquired and used as a confounding variable to separate changes in structure from function. Compared to healthy controls, CAD patients demonstrated reduced CBF in the superior frontal, anterior cingulate (AC), insular, pre- and post-central gyri, middle temporal, and superior temporal regions. Subsequent analysis of these regions demonstrated decreased CVR in the AC, insula, post-central and superior frontal regions. Except in the superior frontal and precentral regions, regional reductions in CBF and CVR were identified in brain areas where no detectable reductions in GMV were observed, demonstrating that these vascular changes were independent of brain atrophy. Because aerobic fitness training can improve brain function, potential changes in regional CBF were investigated in the CAD patients after completion of a 6-months exercise-based cardiac rehabilitation program. Increased CBF was observed in the bilateral AC, as well as recovery of CBF in the dorsal aspect of the right AC, where the magnitude of increased CBF was roughly equal to the reduction in CBF at baseline compared to controls. These exercise-related improvements in CBF in the AC is intriguing given the role of this area in cognitive processing and regulation of cardiovascular autonomic control. PMID:26779011

  8. Impact of pacing on systemic ventricular function in L-transposition of the great arteries.

    PubMed

    Hofferberth, Sophie C; Alexander, Mark E; Mah, Douglas Y; Bautista-Hernandez, Victor; del Nido, Pedro J; Fynn-Thompson, Francis

    2016-01-01

    To assess the impact of univentricular versus biventricular pacing (BiVP) on systemic ventricular function in patients with congenitally corrected transposition of the great arteries (ccTGA). We performed a retrospective review of all patients with a diagnosis of ccTGA who underwent pacemaker insertion. From 1993 to 2014, 53 patients were identified from the cardiology database and surgical records. Overall mortality was 7.5% (n = 4). One patient required transplantation and 3 late deaths occurred secondary to end-stage heart failure. Median follow-up was 3.7 years (range, 4 days to 22.5 years). Twenty-five (47%) underwent univentricular pacing only, of these, 8 (32%) developed significant systemic ventricular dysfunction. Twenty-eight (53%) received BiVP, 17 (26%) were upgraded from a dual-chamber system, 11 (21%) received primary BiVP. Fourteen (82%) of the 17 undergoing secondary BiVP demonstrated systemic ventricular dysfunction at the time of pacer upgrade, with 7 (50%) demonstrating improved systemic ventricular function after pacemaker upgrade. Overall, 42 (79%) patients underwent univentricular pacing, with 22 (52%) developing significant systemic ventricular dysfunction. In contrast, the 11 (21%) who received primary BiVP had preserved systemic ventricular function at latest follow-up. Late-onset systemic ventricular dysfunction is a major complication associated with the use of univentricular pacing in patients with ccTGA. All patients with ccTGA who develop heart block should undergo primary biventricular pacing, as this prevents late systemic ventricular dysfunction. Preemptive placement of BiVP leads at the time of anatomical repair or other permanent palliative procedure will facilitate subsequent BiVP should heart block develop. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  9. Effectiveness of an early mobilization program on functional capacity after coronary artery bypass surgery: A randomized controlled trial protocol

    PubMed Central

    da Costa Torres, Daniel; dos Santos, Priscila Maria Ramos; Reis, Helder José Lima; Paisani, Denise Moraes; Chiavegato, Luciana Dias

    2016-01-01

    Background: Muscle atrophy and prolonged inactivity are associated with an increased sensation of fatigue and reduced functional capacity in the postoperative period in patients undergoing coronary artery bypass grafting. Cardiac rehabilitation after hospital discharge is highly recommended and contributes to improvement in functional capacity and quality of life. However, few studies have evaluated the effectiveness of early mobilization protocols during hospitalization on the patterns of physical activity and functional capacity after coronary artery bypass grafting. Objective: To investigate the effectiveness of an early mobilization program on the functional capacity of patients undergoing coronary artery bypass grafting in the short and long term. Methods: This is a prospective, randomized, controlled, single-blind trial protocol that will evaluate 66 consecutive patients undergoing coronary artery bypass grafting. Patients will be randomized into two training groups: the control group (N = 33), which will perform breathing exercises and the intervention group (N = 33), which will perform breathing exercises and aerobic exercises. The groups will receive treatment from first to the seventh postoperative day, twice daily. In the preoperative period, the following outcomes will be assessed: physical activity level (Baecke Questionnaire), Functional Independence Measure, and functional capacity (6-min walking test). Functional capacity will be reassessed after the 7th and 60th postoperative day. Pulmonary complications and length of hospital stay will also be evaluated. Statistical analysis will be calculated using linear mixed models and will be based on intention-to-treat. The level of significance will be set at α = 5%. PMID:28348739

  10. Preoperative Renal Function Predicts Hospital Costs and Length of Stay in Coronary Artery Bypass Grafting.

    PubMed

    LaPar, Damien J; Rich, Jeffrey B; Isbell, James M; Brooks, Charles H; Crosby, Ivan K; Yarboro, Leora T; Ghanta, Ravi K; Kern, John A; Brown, Michael; Quader, Mohammed A; Speir, Alan M; Ailawadi, Gorav

    2016-02-01

    Renal failure remains a major source of morbidity after cardiac surgery. Whereas the relationship between poor renal function and worse cardiac surgical outcomes is well established, the ability to predict the impact of preoperative renal insufficiency on hospital costs and health care resource utilization remains unknown. Patient records from a statewide The Society for Thoracic Surgeons (STS) database linked with estimated cost data were evaluated for isolated coronary artery bypass graft (CABG) operations (2000 to 2012). Patients with documented preoperative renal failure/dialysis were excluded. Preoperative renal function was determined using calculated creatinine clearance (CrCl). Multivariable regression analyses utilizing restricted cubic splines evaluated the continuous relationship between CrCl and risk-adjusted outcomes. A total of 46,577 isolated CABG operations were evaluated with a median STS predicted risk of mortality score of 1.2% (interquartile range, 0.7% to 2.4%), including 9% off-pump CABG. Median CrCl was 85 mL/min (range, 2 to 120 mL/min), and median total cost was $25,011. After adjustment for preoperative risk factors, worsening CrCl (declining renal function) was highly associated with greater total costs of hospitalization (coefficient = -122, p < 0.001) and postoperative length of stay (coefficient = -0.03, p < 0.001). Furthermore, predicted total costs were incrementally increased by 10%, 20%, and 30% with worsening of CrCl from 80 mL/min to 60, 40, and 20 mL/min. As expected, decreasing CrCl was also associated with an increased risk-adjusted likelihood for hemodialysis and mortality (both p < 0.001). Preoperative renal function is highly associated with the cost of CABG. Assessment of renal function may be used to preoperatively predict cost and resource utilization. Optimizing renal function preoperatively has the potential to improve patient quality and costs by approximately 6% ($1,250) for every 10 mL/min improvement in

  11. Impact of Intensive Physiotherapy on Cognitive Function after Coronary Artery Bypass Graft Surgery.

    PubMed

    Cavalcante, Elder Dos Santos; Magario, Rosmeiri; Conforti, César Augusto; Cipriano Júnior, Gerson; Arena, Ross; Carvalho, Antonio Carlos C; Buffolo, Enio; Luna Filho, Bráulio

    2014-11-01

    Background: Coronary artery bypass graft (CABG) is a standard surgical option for patients with diffuse and significant arterial plaque. This procedure, however, is not free of postoperative complications, especially pulmonary and cognitive disorders. Objective: This study aimed at comparing the impact of two different physiotherapy treatment approaches on pulmonary and cognitive function of patients undergoing CABG. Methods: Neuropsychological and pulmonary function tests were applied, prior to and following CABG, to 39 patients randomized into two groups as follows: Group 1 (control) - 20 patients underwent one physiotherapy session daily; and Group 2 (intensive physiotherapy) - 19 patients underwent three physiotherapy sessions daily during the recovery phase at the hospital. Non-paired and paired Student t tests were used to compare continuous variables. Variables without normal distribution were compared between groups by using Mann-Whitney test, and, within the same group at different times, by using Wilcoxon test. The chi-square test assessed differences of categorical variables. Statistical tests with a p value ≤ 0.05 were considered significant. Results: Changes in pulmonary function were not significantly different between the groups. However, while Group 2 patients showed no decline in their neurocognitive function, Group 1 patients showed a decline in their cognitive functions (P ≤ 0.01). Conclusion: Those results highlight the importance of physiotherapy after CABG and support the implementation of multiple sessions per day, providing patients with better psychosocial conditions and less morbidity.Fundamento: A cirurgia de revascularização miocárdica (CRM) é a opção cirúrgica padrão para pacientes com placas arteriais difusas e significativas. Tal procedimento, no entanto, não é desprovido de complicações pós-operatórias, especialmente distúrbios pulmonares e cognitivos. Objetivo: Comparar o impacto de duas abordagens fisioterap

  12. The functional significance of calcification of coronary arteries as detected on CT.

    PubMed

    Timins, M E; Pinsk, R; Sider, L; Bear, G

    1991-12-01

    We evaluated the coronary arteries on computed tomography (CT) scans of the chest and on coronary angiograms of 27 patients who underwent both studies. We related the presence or absence of coronary artery calcification on CT to percentage stenosis on angiogram. For the left anterior descending artery (LAD), the likelihood of calcification rose proportionately with degree of stenosis; this was less true for the circumflex, and not true for the right coronary artery (RCA). The sensitivity of CT in detecting coronary artery calcification in patients with angiographic criteria of significant coronary artery disease (CAD) was 78% for the LAD, 63% for the circumflex, and 16% for the RCA. Specificities were 78%, 80%, and 100%, and positive predictive values were 88%, 83%, and 100%. The high positive predictive values suggest that coronary artery calcification diagnosed by chest CT has a high correlation with clinically significant CAD. Therefore, when we detect such calcification in a patient without documented heart disease, we suggest that a cardiac workup is indicated.

  13. Sequential changes of left ventricular function after cineangiography in normal heart and coronary artery disease.

    PubMed

    Kaku, K; Hirota, Y; Shimizu, G; Furubayashi, K; Kawamura, K

    1984-06-01

    To evaluate the effect of contrast material on left ventricular (LV) function, LV pressure and its first derivative were continuously monitored during and after LV cineangiography with Mikro-tip angiocatheters in 15 normal subjects (Group 1) and patients with coronary artery disease (CAD) without LV asynergy (Group 2, n = 10), with mild asynergy (Group 3, n = 12) and severe asynergy (Group 4, n = 13). In all 4 groups, systolic hypotension, decrease of negative dP/dt, and prolonged time constant of LV pressure fall (T) were observed in 30 seconds after dye injection, and all these parameters returned to the control value in 2 minutes. LV end-diastolic pressure (EDP) began to elevate at one minute, reached its peak at 2 minutes, and stayed elevated for 7 minutes. Although significant decrease in LV systolic pressure was seen, indexes of LV contractility, peak positive dP/dt and (dP/dt)/DP40, showed increase in all groups. No different directional changes of these parameters were observed among 4 groups. The degree of LVEDP elevation was parallel to the diastolic elastic stiffness constant (K) in Group 1 (r = 0.64, (p less than 0.05). It is concluded that systolic hypotension and prolonged relaxation are only transient, and elevation of LVEDP after the contrast material injection seems to be the effect of only acute volume overload.

  14. Real-Time Functional MRI Using Pseudo-Continuous Arterial Spin Labeling

    PubMed Central

    Hernandez-Garcia, Luis; Jahanian, Hesamoddin; Greenwald, Mark K.; Zubieta, Jon-Kar; Peltier, Scott J.

    2011-01-01

    The first implementation of real-time acquisition and analysis of Arterial Spin Labeling (ASL) based functional MRI time series is presented in this article. The implementation uses a pseudo-continuous labeling scheme followed by a spiral k-space acquisition trajectory. Real-time reconstruction of the images, preprocessing and regression analysis of the fMRI data were implemented on a laptop computer interfaced with the MRI scanner. The method allows the user to track the current raw data, subtraction images, and the cumulative t-statistic map overlaid on a cumulative subtraction image. The user is also able to track the time course of individual time courses, and interactively select an ROI as a nuisance covariate. The pulse sequence allows the user to adjust acquisition and labeling parameters while observing their effect on the image within two successive TRs. This method is illustrated on a stimulation paradigm consisting of simultaneous finger-tapping and visual stimulation and on a bimanual finger tapping task alternating hands. PMID:21446035

  15. Influence of cigarette smoking on human autonomic function

    NASA Technical Reports Server (NTRS)

    Niedermaier, O. N.; Smith, M. L.; Beightol, L. A.; Zukowska-Grojec, Z.; Goldstein, D. S.; Eckberg, D. L.

    1993-01-01

    BACKGROUND. Although cigarette smoking is known to lead to widespread augmentation of sympathetic nervous system activity, little is known about the effects of smoking on directly measured human sympathetic activity and its reflex control. METHODS AND RESULTS. We studied the acute effects of smoking two research-grade cigarettes on muscle sympathetic nerve activity and on arterial baroreflex-mediated changes of sympathetic and vagal neural cardiovascular outflows in eight healthy habitual smokers. Measurements were made during frequency-controlled breathing, graded Valsalva maneuvers, and carotid baroreceptor stimulation with ramped sequences of neck pressure and suction. Smoking provoked the following changes: Arterial pressure increased significantly, and RR intervals, RR interval spectral power at the respiratory frequency, and muscle sympathetic nerve activity decreased. Plasma nicotine levels increased significantly, but plasma epinephrine, norepinephrine, and neuropeptide Y levels did not change. Peak sympathetic nerve activity during and systolic pressure overshoots after Valsalva straining increased significantly in proportion to increases of plasma nicotine levels. The average carotid baroreceptor-cardiac reflex relation shifted rightward and downward on arterial pressure and RR interval axes; average gain, operational point, and response range did not change. CONCLUSIONS. In habitual smokers, smoking acutely reduces baseline levels of vagal-cardiac nerve activity and completely resets vagally mediated arterial baroreceptor-cardiac reflex responses. Smoking also reduces muscle sympathetic nerve activity but augments increases of sympathetic activity triggered by brief arterial pressure reductions. This pattern of autonomic changes is likely to influence smokers' responses to acute arterial pressure reductions importantly.

  16. Influence of cigarette smoking on human autonomic function

    NASA Technical Reports Server (NTRS)

    Niedermaier, O. N.; Smith, M. L.; Beightol, L. A.; Zukowska-Grojec, Z.; Goldstein, D. S.; Eckberg, D. L.

    1993-01-01

    BACKGROUND. Although cigarette smoking is known to lead to widespread augmentation of sympathetic nervous system activity, little is known about the effects of smoking on directly measured human sympathetic activity and its reflex control. METHODS AND RESULTS. We studied the acute effects of smoking two research-grade cigarettes on muscle sympathetic nerve activity and on arterial baroreflex-mediated changes of sympathetic and vagal neural cardiovascular outflows in eight healthy habitual smokers. Measurements were made during frequency-controlled breathing, graded Valsalva maneuvers, and carotid baroreceptor stimulation with ramped sequences of neck pressure and suction. Smoking provoked the following changes: Arterial pressure increased significantly, and RR intervals, RR interval spectral power at the respiratory frequency, and muscle sympathetic nerve activity decreased. Plasma nicotine levels increased significantly, but plasma epinephrine, norepinephrine, and neuropeptide Y levels did not change. Peak sympathetic nerve activity during and systolic pressure overshoots after Valsalva straining increased significantly in proportion to increases of plasma nicotine levels. The average carotid baroreceptor-cardiac reflex relation shifted rightward and downward on arterial pressure and RR interval axes; average gain, operational point, and response range did not change. CONCLUSIONS. In habitual smokers, smoking acutely reduces baseline levels of vagal-cardiac nerve activity and completely resets vagally mediated arterial baroreceptor-cardiac reflex responses. Smoking also reduces muscle sympathetic nerve activity but augments increases of sympathetic activity triggered by brief arterial pressure reductions. This pattern of autonomic changes is likely to influence smokers' responses to acute arterial pressure reductions importantly.

  17. Cognitive impairment and neurovascular function in patients with severe steno-occlusive disease of a main cerebral artery.

    PubMed

    Ishikawa, Mami; Saito, Haruna; Yamaguro, Tomotaka; Ikoda, Masashi; Ebihara, Akira; Kusaka, Gen; Tanaka, Yuichi

    2016-02-15

    Patients with severe steno-occlusive disease of a main cerebral artery may demonstrate cognitive impairment without identification of causative lesions on magnetic resonance imaging. We investigated whether cognitive impairment in these patients is associated with regional cerebral blood flow (rCBF), leukoaraiosis, risk factors of atherosclerosis and cerebrovascular reserve (CVR), which shows so-called clinical neurovascular function. In 65 patients with severe steno-occlusive disease of an internal carotid artery or a middle cerebral artery (MCA) and no cerebral infarction (CI), we examined cognitive function with COGNISTAT, grades of leukoaraiosis, and CBF and CVR as calculated by iodine-123-N-isopropyl-p-iodoamphetamine single photon emission computed tomography and blood data. We compared such values of the left and right sided diseases. rCBF and CVR on the affected side were compared to other side. Logistic regression analysis revealed that CVR correlated with cognitive impairment. There was no significant difference in rCBF, CVR, or COGNISTAT score when comparing the left and right sided diseases. There were good correlations between CBF or CVR of the ipsilateral MCA area and ipsilateral and contralateral other areas. Cognitive impairment is associated with CVR in the whole brain. Nonselective widespread neurovascular mild dysfunction can be a reason for cognitive impairment in patients with severe steno-occlusive disease of a main cerebral artery and no CI. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Pressure Myography to Study the Function and Structure of Isolated Small Arteries.

    PubMed

    Schjørring, Olav L; Carlsson, Rune; Simonsen, Ulf

    2015-01-01

    Small arteries play an important role in regulation of peripheral resistance and organ perfusion. Here we describe a series of methods allowing measurements in pressurized segments of small arteries from the systemic and coronary circulation of mice as well as other species. The pressure myography techniques described include measurements of wall structure, wall stress, strain, and myogenic tone. The pressurized perfused small arteries also allow evaluation of responses to increases in pressure, flow, and drugs, where the main readout is changes in vascular diameter.

  19. Relative sensitivities of DCE-MRI pharmacokinetic parameters to arterial input function (AIF) scaling.

    PubMed

    Li, Xin; Cai, Yu; Moloney, Brendan; Chen, Yiyi; Huang, Wei; Woods, Mark; Coakley, Fergus V; Rooney, William D; Garzotto, Mark G; Springer, Charles S

    2016-08-01

    Dynamic-Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) has been used widely for clinical applications. Pharmacokinetic modeling of DCE-MRI data that extracts quantitative contrast reagent/tissue-specific model parameters is the most investigated method. One of the primary challenges in pharmacokinetic analysis of DCE-MRI data is accurate and reliable measurement of the arterial input function (AIF), which is the driving force behind all pharmacokinetics. Because of effects such as inflow and partial volume averaging, AIF measured from individual arteries sometimes require amplitude scaling for better representation of the blood contrast reagent (CR) concentration time-courses. Empirical approaches like blinded AIF estimation or reference tissue AIF derivation can be useful and practical, especially when there is no clearly visible blood vessel within the imaging field-of-view (FOV). Similarly, these approaches generally also require magnitude scaling of the derived AIF time-courses. Since the AIF varies among individuals even with the same CR injection protocol and the perfect scaling factor for reconstructing the ground truth AIF often remains unknown, variations in estimated pharmacokinetic parameters due to varying AIF scaling factors are of special interest. In this work, using simulated and real prostate cancer DCE-MRI data, we examined parameter variations associated with AIF scaling. Our results show that, for both the fast-exchange-limit (FXL) Tofts model and the water exchange sensitized fast-exchange-regime (FXR) model, the commonly fitted CR transfer constant (K(trans)) and the extravascular, extracellular volume fraction (ve) scale nearly proportionally with the AIF, whereas the FXR-specific unidirectional cellular water efflux rate constant, kio, and the CR intravasation rate constant, kep, are both AIF scaling insensitive. This indicates that, for DCE-MRI of prostate cancer and possibly other cancers, kio and kep may be more suitable imaging

  20. Sonographic Evaluation of Endothelial Function in Brachial Arteries of Adult Stroke Patients.

    PubMed

    Omisore, Adeleye Dorcas; Ayoola, Oluwagbemiga Oluwole; Ibitoye, Bolanle Olubunmi; Fawale, Michael Bimbola; Adetiloye, Victor Adebayo

    2017-02-01

    Brachial artery flow-mediated dilatation on sonography is used to evaluate endothelial dysfunction, which is a key event in the development of atherosclerosis and predates structural atherosclerotic lesions by many years. Atherosclerosis has been implicated in the pathophysiologic mechanisms of ischemic stroke. The aim of this study was to determine the association between brachial flow-mediated dilatation, the presence of cardiovascular risk factors, and acute stroke. We evaluated right brachial arteries of 150 participants (50 stroke patients, 50 patients with cardiovascular risk factors, and 50 healthy control individuals) with B-mode sonography before and 5 minutes after sphygmomanometer cuff application to their forearms. Analysis of variance for multiple comparisons was used between each group. Mean ages of the stroke, risk factor, and control groups ± SD were 57.5 ± 14.8, 52.4 ± 16.0, and 56.1 ± 14.9 years, respectively (P = .235). Flow-mediated dilatation rates were 4.37% ± 1.50%, 5.62% ± 1.23%, and 10.33% ± 1.96% in the stroke, risk factor, and control groups (P ≤ .001). Dilatation was 3.79% ± 0.92% in ischemic stroke compared with 6.02% ± 1.62% in intracerebral hemorrhage (P < .001), but there was no significant difference in dilatation between ischemic stroke subtypes according to the Trial of ORG 10172 in Acute Stroke Treatment classification (P = .301). Brachial flow-mediated dilatation was significantly lower in patients with acute stroke compared with controls matched for vascular risk factors and healthy controls. Decreased vascular endothelial function in stroke patients was particularly related to cerebral infarction compared with intracerebral hemorrhage. Brachial flow-mediated dilatation did not differentiate ischemic stroke subtypes by the Trial of ORG 10172 in Acute Stroke Treatment classification. Flow-mediated dilatation was therefore found to be a marker of cardiovascular risk

  1. Relative sensitivities of DCE-MRI pharmacokinetic parameters to arterial input function (AIF) scaling

    NASA Astrophysics Data System (ADS)

    Li, Xin; Cai, Yu; Moloney, Brendan; Chen, Yiyi; Huang, Wei; Woods, Mark; Coakley, Fergus V.; Rooney, William D.; Garzotto, Mark G.; Springer, Charles S.

    2016-08-01

    Dynamic-Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) has been used widely for clinical applications. Pharmacokinetic modeling of DCE-MRI data that extracts quantitative contrast reagent/tissue-specific model parameters is the most investigated method. One of the primary challenges in pharmacokinetic analysis of DCE-MRI data is accurate and reliable measurement of the arterial input function (AIF), which is the driving force behind all pharmacokinetics. Because of effects such as inflow and partial volume averaging, AIF measured from individual arteries sometimes require amplitude scaling for better representation of the blood contrast reagent (CR) concentration time-courses. Empirical approaches like blinded AIF estimation or reference tissue AIF derivation can be useful and practical, especially when there is no clearly visible blood vessel within the imaging field-of-view (FOV). Similarly, these approaches generally also require magnitude scaling of the derived AIF time-courses. Since the AIF varies among individuals even with the same CR injection protocol and the perfect scaling factor for reconstructing the ground truth AIF often remains unknown, variations in estimated pharmacokinetic parameters due to varying AIF scaling factors are of special interest. In this work, using simulated and real prostate cancer DCE-MRI data, we examined parameter variations associated with AIF scaling. Our results show that, for both the fast-exchange-limit (FXL) Tofts model and the water exchange sensitized fast-exchange-regime (FXR) model, the commonly fitted CR transfer constant (Ktrans) and the extravascular, extracellular volume fraction (ve) scale nearly proportionally with the AIF, whereas the FXR-specific unidirectional cellular water efflux rate constant, kio, and the CR intravasation rate constant, kep, are both AIF scaling insensitive. This indicates that, for DCE-MRI of prostate cancer and possibly other cancers, kio and kep may be more suitable imaging

  2. Functional Expression Profile of Voltage-Gated K(+) Channel Subunits in Rat Small Mesenteric Arteries.

    PubMed

    Cox, Robert H; Fromme, Samantha

    2016-06-01

    Multiple K v channel complexes contribute to total K v current in numerous cell types and usually subserve different physiological functions. Identifying the complete compliment of functional K v channel subunits in cells is a prerequisite to understanding regulatory function. It was the goal of this work to determine the complete K v subunit compliment that contribute to functional K v currents in rat small mesenteric artery (SMA) myocytes as a prelude to studying channel regulation. Using RNA prepared from freshly dispersed myocytes, high levels of K v 1.2, 1.5, and 2.1 and lower levels of K v 7.4 α-subunit expressions were demonstrated by quantitative PCR and confirmed by Western blotting. Selective inhibitors correolide (K v 1; COR), stromatoxin (K v 2.1; ScTx), and linopirdine (K v 7.4; LINO) decreased K v current at +40 mV in SMA by 46 ± 4, 48 ± 4, and 6.5 ± 2 %, respectively, and K v current in SMA was insensitive to α-dendrotoxin. Contractions of SMA segments pretreated with 100 nmol/L phenylephrine were enhanced by 27 ± 3, 30 ± 8, and 7 ± 3 % of the response to 120 mmol/L KCl by COR, ScTX, and LINO, respectively. The presence of K v 6.1, 9.3, β1.1, and β1.2 was demonstrated by RT-PCR using myocyte RNA with expressions of K vβ1.2 and K v 9.3 about tenfold higher than K vβ1.1 and K v 6.1, respectively. Selective inhibitors of K v 1.3, 3.4, 4.1, and 4.3 channels also found at the RNA and/or protein level had no significant effect on K v current or contraction. These results suggest that K v current in rat SMA myocytes are dominated equally by two major components consisting of K v 1.2-1.5-β1.2 and K v 2.1-9.3 channels along with a smaller contribution from K v 7.4 channels but differences in voltage dependence of activation allows all three to provide significant contributions to SMA function at physiological voltages.

  3. Endogenous angiotensin II in the paraventricular nucleus regulates arterial pressure during hypotension in rat, a single-unit study.

    PubMed

    Khanmoradi, Mehrangiz; Nasimi, Ali

    2017-01-01

    The hypothalamic paraventricular nucleus (PVN) controls cardiovascular regulation through vasopressin and sympathetic system. The PVN contains angiotensin II (AngII) and AngII receptors. We have already shown that microinjection of AngII into PVN produced a pressor response concomitant with an increase in firing rate of some PVN neurons. This study was performed to find if PVN AngII plays a regulatory function during hypotension. Hypovolemic-hypotension was induced and the possible role of the PVN AngII in returning arterial pressure toward normal was assessed by monitoring cardiovascular response and single-unit activity of the PVN neurons. Hemorrhage augmented the pressor, tachycardic and single-unit responses to AngII. After-hemorrhage injection of PD123319, an AT2 antagonist, into PVN resulted in a significant decrease in firing rate of some neurons, indicating that AngII was released into the PVN due to hemorrhage. Using single-unit recording, we found that PVN receives electrical signals from baroreceptors and from circulating AngII through circumventricular organs. In addition, by producing hemorrhagic-hypotension and bilateral blockade of AT2 receptors of the PVN, we found that AngII regulates arterial pressure toward normal during hypotension. So for the first time, it was verified that brain renin-angiotensin system is also a major regulatory system of the cardiovascular system. Copyright © 2016 Elsevier Ireland Ltd and Japan Neuroscience Society. All rights reserved.

  4. The Effects of Right Ventricular Apical Pacing Frequency on Left Ventricle Function and Pulmonary Artery Pressure.

    PubMed

    Fanari, Zaher; Hammami, Sumaya; Hammami, Muhammad Baraa; Hammami, Safa; Shuraih, Mossaab

    2015-08-01

    We studied the effect of the frequency of right ventricular (HV) pacing on left ventricle (LV) function pulmonary hypertension. The incidence of new or worsening pulmonary hypertension after permanent pacemaker (PPM) or implantable cardioverter defibrillator (lCD) lead placement has not been well investigated. We reviewed the charts of all patients undergoing PPM or ICD lead placement in our electrophysiology laboratory from December 2007 to December 2012. Two hundred and six patients (120 with PPM and 86 with ICD) had baseline echocardiography within six months before, and a follow up study at least six months after lead insertion. The mean age was 74 ± 14 years; 56 percent were men. The follow-up period was 29 ± 19 months. RV pacing was associated with a worsening of left ventricular ejection fraction (LVEF) in patients with high frequency of RV (55 ± 16 vs. 44 ± 18; P = 0.001), but not with those with low frequency pacing (55 ± 16 vs. 54 ± 17; P = 0.87). Similarly, RV pacing was associated with a worsening in both right ventricular systolic pressure (RVSP) (42 ± 14 vs. 48 ± 15; P = 0.01) and Pulmonary Artery Systolic Pressure (PASP) (50 ± 17 vs. 56 ± 18; P = 0.005) in patients with high frequency RV, but not in those with low frequency RV pacing [RVSP (43 ± 12 vs. 46 ± 13; P = 0.06) and PASP (51 ± 15 vs. 54 ± 16; P = 0.11)]. PPM or IICD lead implantation worsens LV function and pulmonary hypertension in patients with high frequency of RV pacing frequency. This is probably caused by the mechanical dyssynchrony induced by RV pacing.

  5. Impact of Diabetes and Peripheral Arterial Occlusive Disease on the Functional Microcirculation at the Plantar Foot

    PubMed Central

    Kabbani, Mohammad; Rotter, Robert; Busche, Marc; Wuerfel, Waldemar; Jokuszies, Andreas; Knobloch, Karsten; Vogt, Peter M.

    2013-01-01

    Background: Plastic and reconstructive surgeons are commonly faced with chronic ulcerations and consecutive wound infections of the feet as complications in patients with diabetes and/or peripheral arterial occlusive disease (PAOD). Microcirculatory changes seem to play an important role. However, the evaluation of functional changes in the soft tissue microcirculation at the plantar foot using combined Laser-Doppler and Photospectrometry System has not yet been performed in patients with DM or PAOD. Methods: A prospective, controlled cohort study was designed consisting of a total of 107 subjects allocated to 1 of 3 groups—group A: healthy subjects (57% males, 63.3 y); group B: patients with diabetes mellitus (DM) (53% males, 59.4 y); and group C: patients with PAOD (81% males, 66.1 y). Microcirculatory data were assessed using a combined Laser-Doppler and Photospectrometry System. Results: Global cutaneous oxygen saturation microcirculation at the plantar foot of healthy individuals was 8.4% higher than in patients with DM and 8.1% higher than in patients with PAOD (both P = 0.033). Patients with diabetes did not show significant differences in global cutaneous blood flow when compared with either healthy subjects or patients suffering from PAOD. Conclusions: Functional microcirculation at the plantar foot differs between healthy subjects and patients suffering from diabetes or PAOD of the same age. Patients with either diabetes or PAOD demonstrate deteriorated cutaneous oxygen saturation with equivalent blood perfusion at the plantar foot. More clinical studies have to be conducted to evaluate therapeutical methods that might ameliorate cutaneous oxygen saturation within diabetic foot disease and PAOD. PMID:25289243

  6. Control of arterial pressure and renal function during glucocorticoid excess in dogs.

    PubMed

    Hall, J E; Morse, C L; Smith, M J; Young, D B; Guyton, A C

    1980-01-01

    This study was designed to investigate the long-term effects of glucocorticoids on the control of mean arterial pressure (MAP) and renal function. Infusion of 10 mg/day of methylprednisolone (MP), a glucocorticoid with minimal mineralocorticoid activity, for 10 days in six intact conscious dogs maintained on a sodium intake of 78 mEq/day resulted in a decrease in MAP from 98 +/- 1 to 89 +/- 2 mm Hg, a decrease in sodium iothalamate space to 89 +/- 2% of control, and a marked increase in glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and urinary sodium excretion. Chronic infusion of MP at doses of 2--800 mg/day in four dogs maintained on low (5 mEq/day) or high sodium intakes (160--223 mEq/day) also caused increases in GFR and ERPF, as well as natriuresis and decreased sodium iothalamate space, while causing either no change or a slight reduction in MAP. To determine whether glucocorticoids potentiate the chronic effects of angiotensin II (AII) on MAP and renal function, MP was infused in dogs undergoing AII infusion (5 ng/kg/min). During AII hypertension, chronic infusion of 5 or 10 mg/day of MP also resulted in a marked renal vasodilation, natriuresis, and reductions in sodium iothalamate space, while causing small reductions in MAP. Thus, we found no evidence that chronic glucocorticoid excess causes hypertension in dogs, or that glucocorticoids potentiate the blood pressure or renal effects of AII. Instead, glucocorticoids tended to reduce MAP, probably because of chronic renal vasodilation, increased excretion of sodium, and volume depletion.

  7. Translational informatics approach for identifying the functional molecular communicators linking coronary artery disease, infection and inflammation.

    PubMed

    Sharma, Ankit; Ghatge, Madankumar; Mundkur, Lakshmi; Vangala, Rajani Kanth

    2016-05-01

    Translational informatics approaches are required for the integration of diverse and accumulating data to enable the administration of effective translational medicine specifically in complex diseases such as coronary artery disease (CAD). In the current study, a novel approach for elucidating the association between infection, inflammation and CAD was used. Genes for CAD were collected from the CAD‑gene database and those for infection and inflammation were collected from the UniProt database. The cytomegalovirus (CMV)‑induced genes were identified from the literature and the CAD‑associated clinical phenotypes were obtained from the Unified Medical Language System. A total of 55 gene ontologies (GO) termed functional communicator ontologies were identified in the gene sets linking clinical phenotypes in the diseasome network. The network topology analysis suggested that important functions including viral entry, cell adhesion, apoptosis, inflammatory and immune responses networked with clinical phenotypes. Microarray data was extracted from the Gene Expression Omnibus (dataset: GSE48060) for highly networked disease myocardial infarction. Further analysis of differentially expressed genes and their GO terms suggested that CMV infection may trigger a xenobiotic response, oxidative stress, inflammation and immune modulation. Notably, the current study identified γ‑glutamyl transferase (GGT)‑5 as a potential biomarker with an odds ratio of 1.947, which increased to 2.561 following the addition of CMV and CMV‑neutralizing antibody (CMV‑NA) titers. The C‑statistics increased from 0.530 for conventional risk factors (CRFs) to 0.711 for GGT in combination with the above mentioned infections and CRFs. Therefore, the translational informatics approach used in the current study identified a potential molecular mechanism for CMV infection in CAD, and a potential biomarker for risk prediction.

  8. Preservation of retinal structure and function after cilioretinal artery occlusion: a case report

    PubMed Central

    Brown, Craig J

    2016-01-01

    Cilioretinal artery occlusion is a cause of sudden, often catastrophic loss of central vision. There are no established effective treatments. Recently, a patient presented 24 hours after a cilioretinal artery occlusion, following a cardiac catheterization prior to which her blood thinners had been discontinued. Lacking an effective way to address the severe retinal ischemic oxidative stress, she was offered, under compassionate use, a multivitamin complex designed to address retinal ischemia and oxidative stress. Significant components of this product are L-methylfolate and n-acetyl cysteine. The patient experienced a rapid unexpected improvement in vision and preservation of retinal structure, suggesting that marked improvement in retinal artery occlusions outcomes may be possible as late as 24 hours postocclusion. This is the third reported case of cilioretinal artery occlusion associated with cardiac catheterization. PMID:26929671

  9. Endothelin receptors mediating functional responses in human small arteries and veins.

    PubMed Central

    Riezebos, J.; Watts, I. S.; Vallance, P. J.

    1994-01-01

    1. In the present study, responses of human omental small arteries and veins to endothelin-1 and endothelin-3 were characterized by use of the ETB receptor selective agonist, sarafotoxin S6c, the ETA receptor antagonist, BQ123, the ETB receptor antagonist, IRL1038, the NO-synthase inhibitor NG-monomethyl-L-arginine (L-NMMA, 300 microM) and indomethacin (10 microM). 2. Small arteries (internal diameter 413 +/- 22 microns) and parallel running veins (646 +/- 35 microns) were mounted in a myograph under a normalized tension equivalent to 90% of a transmural pressure of 100 mmHg and 19 mmHg in vivo, respectively. 3. In small arteries and veins, endothelin-1 caused a concentration-dependent increase in wall tension (Emax = 3.90 +/- 0.56 mN mm-1 and 1.90 m +/- 0.32 mN mm-1 respectively, P < 0.05) and was equipotent (arteries: pD2 = 8.91 +/- 0.11; veins: pD2 = 8.63 +/- 0.08, NS). In endothelium intact arteries, L-NMMA significantly enhanced the sensitivity to endothelin-1 (pD2 control: 8.92 +/- 0.16; pD2 L-NMMA: 9.37 +/- 0.11; P < 0.05). L-NMMA did not affect the sensitivity of veins to endothelin-1. Indomethacin was without effect in arteries and veins. In veins, endothelin-3 was about a hundred times less potent than endothelin-1 and showed a biphasic response curve. Small arteries did not contract to endothelin-3. Neither small arteries nor veins contracted to sarafotoxin S6c. Furthermore, no relaxation to endothelin-1 or sarafotoxin S6c was seen in any precontracted vessels.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8004404

  10. Modulation of human muscle spindle discharge by arterial pulsations--functional effects and consequences.

    PubMed

    Birznieks, Ingvars; Boonstra, Tjeerd W; Macefield, Vaughan G

    2012-01-01

    Arterial pulsations are known to modulate muscle spindle firing; however, the physiological significance of such synchronised modulation has not been investigated. Unitary recordings were made from 75 human muscle spindle afferents innervating the pretibial muscles. The modulation of muscle spindle discharge by arterial pulsations was evaluated by R-wave triggered averaging and power spectral analysis. We describe various effects arterial pulsations may have on muscle spindle afferent discharge. Afferents could be "driven" by arterial pulsations, e.g., showing no other spontaneous activity than spikes generated with cardiac rhythmicity. Among afferents showing ongoing discharge that was not primarily related to cardiac rhythmicity we illustrate several mechanisms by which individual spikes may become phase-locked. However, in the majority of afferents the discharge rate was modulated by the pulse wave without spikes being phase locked. Then we assessed whether these influences changed in two physiological conditions in which a sustained increase in muscle sympathetic nerve activity was observed without activation of fusimotor neurones: a maximal inspiratory breath-hold, which causes a fall in systolic pressure, and acute muscle pain, which causes an increase in systolic pressure. The majority of primary muscle spindle afferents displayed pulse-wave modulation, but neither apnoea nor pain had any significant effect on the strength of this modulation, suggesting that the physiological noise injected by the arterial pulsations is robust and relatively insensitive to fluctuations in blood pressure. Within the afferent population there was a similar number of muscle spindles that were inhibited and that were excited by the arterial pulse wave, indicating that after signal integration at the population level, arterial pulsations of opposite polarity would cancel each other out. We speculate that with close-to-threshold stimuli the arterial pulsations may serve as an

  11. The effects of atorvastatin therapy on endothelıal function in patients with coronary artery disease

    PubMed Central

    Yildiz, Ahmet; Cakar, M Akif; Baskurt, Murat; Okcun, Barıs; Guzelsoy, Deniz; Coskun, Ugur

    2007-01-01

    Background Statins improve the endothelial function in patients with coronary artery disease (CAD). However, they contribute to the substantial decrease in coronary heart disease by reducing plasma cholesterol levels. They also, reduce oxidative stress, stabilize the atherosclerotic plaque and inhibit inflammatory response. These functions of statins have been briefly described as pleiotropic effects. The aim of our study was to evaluate the effect of atorvastatin therapy on endothelial functions in patients with CAD. Methods Fourty-nine patients (40 men, 9 women, mean age 59 +/- 11 years) with diagnosed CAD were selected as the study group. The patients were given 10 mg/day atorvastatin for 12 weeks. If the target cholesterol levels has not been achieved 6 weeks after the treatment, then the daily atorvastatin dosage has been increased. The endothelial function was evaluated by flow mediated dilatation (FMD) of the brachial artery. Results It has been figured out that 12 weeks later, atorvastatin caused a statistically significant decrease in the plasma levels of LDL-cholesterol and total cholesterol (p < 0,0001). Meanwhile, it was determined that the FMD got statistically significant improved 12 weeks after the atorvastatin therapy (8,1%–4,2%, p < 0,001). However there was no statistically significant change in non-endothelium dependent dilatation (NID). Conclusion Endothelium derived vasodilatation (EBD), which was non-invasively detected via brachial artery ultrasonography, had statistically significant improvment within 12 weeks of atorvastatin therapy whereas non-endothelium dependent dilatation (NID) had no change. PMID:18163915

  12. Intra-arterial transplantation of low-dose stem cells provides functional recovery without adverse effects after stroke.

    PubMed

    Fukuda, Yuhtaka; Horie, Nobutaka; Satoh, Katsuya; Yamaguchi, Susumu; Morofuji, Youichi; Hiu, Takeshi; Izumo, Tsuyoshi; Hayashi, Kentaro; Nishida, Noriyuki; Nagata, Izumi

    2015-04-01

    Cell transplantation therapy for cerebral infarction has emerged as a promising treatment to reduce brain damage and enhance functional recovery. We previously reported that intra-arterial delivery of bone marrow mesenchymal stem cells (MSCs) enables superselective cell administration to the infarct area and results in significant functional recovery after ischemic stroke in a rat model. However, to reduce the risk of embolism caused by the transplanted cells, an optimal cell number should be determined. At 24 h after middle cerebral artery occlusion and reperfusion, we administered human MSCs (low dose: 1 × 10(4) cells; high dose: 1 × 10(6) cells) and then assessed functional recovery, inflammatory responses, cell distribution, and mortality. Rats treated with high- or low-dose MSCs showed behavioral recovery. At day 8 post-stroke, microglial activation was suppressed significantly, and interleukin (IL)-1β and IL-12p70 were reduced in both groups. Although high-dose MSCs were more widely distributed in the cortex and striatum of rats, th