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. Arterial baroreceptors in the management of systemic hypertension

    PubMed Central

    Kougias, Panagiotis; Weakley, Sarah M.; Yao, Qizhi; Lin, Peter H.; Chen, Changyi

    2010-01-01

    Summary Hypertension is a multifactorial disease associated with significant morbidity. Increased sympathetic nervous system activity has been noted as an important etiologic factor and is, in part, regulated by afferent input arising from arterial and cardiopulmonary baroreceptors, activation of which causes inhibition of sympathetic output. It was thought for many years that baroreceptors control only short-term blood pressure changes, a conclusion stemming from observations in sinoaortic denervation (SAD) animal models and the phenomenon of rapid baroreceptor resetting, also seen in animal models. Newer observations, however, indicate that SAD is rather imperfect and resetting is rarely complete. Recent studies reveal that baroreceptors control sympathetic output on a more long-term basis and participate in fluid volume regulation by the kidney, and thus have the potential to adjust blood pressure chronically. Importantly, these findings are consistent with studies and observations in humans. Meanwhile, a model of electrical stimulation of the carotid sinus has been developed and successfully tested in animals. Following these encouraging results human trials to evaluate the clinical application of electrical carotid sinus manipulation in the treatment of systemic hypertension have commenced, and results so far indicate that this represents an exciting potential tool in the clinician’s armament against chronic arterial hypertension. PMID:20037502

  3. Brain-Derived Neurotrophic Factor in Arterial Baroreceptor Pathways: Implications for Activity-Dependent Plasticity at Baroafferent Synapses

    PubMed Central

    Martin, Jessica L.; Jenkins, Victoria K.; Hsieh, Hui-ya; Balkowiec, Agnieszka

    2008-01-01

    Functional characteristics of the arterial baroreceptor reflex change throughout ontogenesis, including perinatal adjustments of the reflex gain and adult resetting during hypertension. However, the cellular mechanisms that underlie these functional changes are not completely understood. Here, we provide evidence that brain-derived neurotrophic factor (BDNF), a neurotrophin with a well-established role in activity-dependent neuronal plasticity, is abundantly expressed in vivo by a large subset of developing and adult rat baroreceptor afferents. Immunoreactivity to BDNF is present in the cell bodies of baroafferent neurons in the nodose ganglion (NG), their central projections in the solitary tract, and terminal-like structures in the lower brainstem nucleus tractus solitarius (NTS). Using ELISA in situ combined with electrical field stimulation, we show that native BDNF is released from cultured newborn NG neurons in response to patterns that mimic the in vivo activity of baroreceptor afferents. In particular, high-frequency bursting patterns of baroreceptor firing, which are known to evoke plastic changes at baroreceptor synapses, are significantly more effective at releasing BDNF than tonic patterns of the same average frequency. Together, our study indicates that BDNF expressed by first-order baroreceptor neurons is a likely mediator of both developmental and post-developmental modifications at first-order synapses in arterial baroreceptor pathways. PMID:19054281

  4. Brain-derived neurotrophic factor in arterial baroreceptor pathways: implications for activity-dependent plasticity at baroafferent synapses.

    PubMed

    Martin, Jessica L; Jenkins, Victoria K; Hsieh, Hui-ya; Balkowiec, Agnieszka

    2009-01-01

    Functional characteristics of the arterial baroreceptor reflex change throughout ontogenesis, including perinatal adjustments of the reflex gain and adult resetting during hypertension. However, the cellular mechanisms that underlie these functional changes are not completely understood. Here, we provide evidence that brain-derived neurotrophic factor (BDNF), a neurotrophin with a well-established role in activity-dependent neuronal plasticity, is abundantly expressed in vivo by a large subset of developing and adult rat baroreceptor afferents. Immunoreactivity to BDNF is present in the cell bodies of baroafferent neurons in the nodose ganglion, their central projections in the solitary tract, and terminal-like structures in the lower brainstem nucleus tractus solitarius. Using ELISA in situ combined with electrical field stimulation, we show that native BDNF is released from cultured newborn nodose ganglion neurons in response to patterns that mimic the in vivo activity of baroreceptor afferents. In particular, high-frequency bursting patterns of baroreceptor firing, which are known to evoke plastic changes at baroreceptor synapses, are significantly more effective at releasing BDNF than tonic patterns of the same average frequency. Together, our study indicates that BDNF expressed by first-order baroreceptor neurons is a likely mediator of both developmental and post-developmental modifications at first-order synapses in arterial baroreceptor pathways. PMID:19054281

  5. Reflexes from pulmonary arterial baroreceptors in dogs: interaction with carotid sinus baroreceptors

    PubMed Central

    Moore, Jonathan P; Hainsworth, Roger; Drinkhill, Mark J

    2011-01-01

    Abstract In contrast to the reflex vasodilatation occurring in response to stimulation of baroreceptors in the aortic arch, carotid sinuses and coronary arteries, stimulation of receptors in the wall of pulmonary arteries results in reflex systemic vasoconstriction. It is rare for interventions to activate only one reflexogenic region, therefore we investigated how these two types of reflexes interact. In anaesthetized dogs connected to cardiopulmonary bypass, reflexogenic areas of the carotid sinuses, aortic arch and coronary arteries and the pulmonary artery were subjected to independently controlled pressures. Systemic perfusion pressure (SPP) measured in the descending aorta (constant flow) provided an index of systemic vascular resistance. In other experiments, sympathetic efferent neural activity was recorded in fibres dissected from the renal nerve (RSNA). Physiological increases in pulmonary arterial pressure (PAP) induced significant increases in SPP (+39.1 ± 10.4 mmHg) and RSNA (+17.6 ± 2.2 impulses s−1) whereas increases in carotid sinus pressure (CSP) induced significant decreases in SPP (−42.6 ± 10.8 mmHg) and RSNA (−42.8 ± 18.2 impulses s−1) (P < 0.05 for each comparison; paired t test). To examine possible interactions, PAP was changed at different levels of CSP in both studies. With CSP controlled at 124 ± 2 mmHg, the threshold, ‘set point’ and saturation pressures of the PAP–SPP relationship were higher than those with CSP at 60 ± 1 mmHg; this rightward shift was associated with a significant decrease in the reflex gain. Similarly, increasing CSP produced a rightward shift of the PAP–RSNA relationship, although the effect on reflex gain was inconsistent. Furthermore, the responses to changes in CSP were influenced by setting PAP at different levels; increasing the level of PAP from 5 ± 1 to 33 ± 3 mmHg significantly increased the set point and threshold pressures of the CSP–SPP relationship; the reflex gain was not

  6. Aortic wall properties and baroreceptor behaviour at normal arterial pressure and in acute hypertensive resetting in dogs.

    PubMed Central

    Coleridge, H M; Coleridge, J C; Poore, E R; Roberts, A M; Schultz, H D

    1984-01-01

    In order to throw light on the mechanism of acute hypertensive baroreceptor resetting, we examined the relationship between aortic baroreceptor firing and aortic wall properties in anaesthetized dogs as pressure was varied in a number of ways. We recorded baroreceptor impulses from the left aortic nerve, and measured aortic pressure with a catheter-tip transducer and external aortic diameter with ultrasonic transit-time transducers. Narrow anticlockwise hysteresis loops were evident in the pressure-diameter relationship of the upper thoracic aorta, both during the rapid pulsatile pressure changes of the cardiac cycle and during the slow excursions of mean pressure imposed for construction of baroreceptor pressure--response curves. In contrast to the 'phase-lag' response of diameter to pressure, the baroreceptor response was 'phaselead' in character, decreasing when stress-induced creep occurred in the aortic wall. When the mean arterial pressure set-point was increased from 100 to 125 mmHg for 20 min, the hysteresis loops relating mean diameter to mean pressure in the range 60-200 mmHg were displaced along the diameter axis in the direction of wall creep. A reduction in the baroreceptor response to pressure (i.e. resetting) always accompanied this displacement. Administration of ouabain (25-35 micrograms/kg) had no consistent effect on baroreceptor resetting. It has been suggested that acute baroreceptor resetting is akin to adaptation. To investigate the possibility that the two processes are accompanied by similar changes in aortic wall properties, we converted the aorta into a closed sac and distended it with a square wave of pressure. Like resetting, adaptation of the baroreceptor response to maintained pressure was associated with a small degree of creep of the aortic wall. Our results are compatible with the hypothesis that acute hypertensive resetting of aortic baroreceptors is similar to adaptation, both phenomena being attributable to relaxation of

  7. Involvement of vasodilator mechanisms in arterial pressure lability after sino-aortic baroreceptor denervation in rat.

    PubMed Central

    Zhang, Z Q; Barrès, C; Julien, C

    1995-01-01

    1. To examine the regional haemodynamic basis of arterial pressure lability seen after sino-aortic baroreceptor denervation (SAD), simultaneous beat-to-beat recordings of arterial pressure and indices of regional blood flows (Doppler probes around the subdiaphragmatic and lower abdominal aortae and the superior mesenteric artery) were performed in the same conscious rats (n = 7) before, 1 and 14 days after SAD. 2. Acute SAD increased arterial pressure, decreased regional blood flows and vascular conductances, and potentiated the depressor and vasodilator effects of ganglionic blockade with trimethaphan, suggesting sympathetic overactivity. All parameters chronically returned to or near normal. 3. Both acute and chronic SAD increased the variability of arterial pressure and of regional conductances. Arterial pressure lability was characterized by a mixture of depressor and pressor events which were associated with regional vasodilatations and vasoconstrictions, respectively. This haemodynamic pattern was not affected by acute beta-adrenoceptor blockade with propranolol. 4. In conscious rats, the baroreceptor reflex acts to buffer the spontaneous variability of regional vascular conductances and thereby stabilizes arterial pressure. Sino-aortic baroreceptor denervation-induced arterial pressure lability does not depend on the level of sympathetic activation, and is determined by the relative contribution of depressor and pressor events accompanied by extensive vasodilatations and vasoconstrictions, respectively. Vasodilatations are not caused by the stimulation of vascular beta 2-adrenoceptors. PMID:7714834

  8. 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.

  9. 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.

  10. Afferent fibres from pulmonary arterial baroreceptors in the left cardiac sympathetic nerve of the cat

    PubMed Central

    Nishi, K.; Sakanashi, M.; Takenaka, F.

    1974-01-01

    1. Afferent discharges were recorded from the left cardiac sympathetic nerve or the third sympathetic ramus communicans of anaesthetized cats. Twenty-one single units with baroreceptor activity were obtained. 2. The receptors of each unit were localized to the extrapulmonary part of the pulmonary artery, determined by direct mechanical probing of the wall of the pulmonary artery after death of the animals. Conduction velocity of the fibres ranged from 2·5 to 15·7 m/sec. 3. Afferent discharges occurred irregularly under artificial ventilation. The impulse activity was increased when pulmonary arterial pressure was raised by an intravenous infusion of Locke solution, or by occlusion of lung roots, and decreased by bleeding the animal from the femoral artery. 4. Above a threshold pressure, discharges occurred synchronously with the systolic pressure pulse in the pulmonary artery. A progressive further rise in pressure did not produce an increase in the number of impulses per heart beat. Occlusion of lung roots initially elicited a burst of discharges but the number of impulses for each cardiac cycle gradually decreased. 5. The receptors responded to repetitive mechanical stimuli up to a frequency of 10/sec, but failed to respond to stimuli delivered at 20/sec. 6. The results provide further evidence for the presence of afferent fibres in the cardiac sympathetic nerve. These afferent fibres are likely to provide the spinal cord with specific information only on transient changes in pulmonary arterial pressure. PMID:4850456

  11. Right prefrontal activation produced by arterial baroreceptor stimulation: a PET study.

    PubMed

    Weisz, J; Emri, M; Fent, J; Lengyel, Z; Márián, T; Horváth, G; Bogner, P; Trón, L; Adám, G

    2001-10-29

    This study was performed to test the hypothesis of greater right hemispheric involvement in the processing of baroreceptor stimuli. Carotid sinus baroreceptors were stimulated by rhythmically decreasing air pressure in a neck chamber, and under control conditions the thorax was stimulated in a similar manner. Changes in regional cerebral blood flow (rCBF) were measured by PET. Baroreceptor stimulation resulted in rCBF increase in the right anterior-inferior prefrontal cortex (Brodmann areas (BA) 10/44/47) and bilaterally in BA 6/8. We conclude that in at least some stages of baroreceptor information processing the right hemisphere plays a greater role than the left hemisphere. PMID:11711862

  12. Expression of messenger RNAs for peptides and tyrosine hydroxylase in primary sensory neurons that innervate arterial baroreceptors and chemoreceptors.

    PubMed

    Czyzyk-Krzeska, M F; Bayliss, D A; Lawson, E E; Millhorn, D E

    1991-08-01

    Retrograde fiber tracing and in situ hybridization were used to determine expression of mRNAs for preprotachykinin A (ppTA), calcitonin gene related peptide (CGRP), preproenkephalin A (ENK), neuropeptide tyrosine (NPY) and somatostatin (SOM) as well as tyrosine hydroxylase (TH) in the petrosal ganglia primary sensory neurons which innervate carotid sinus baroreceptors and carotid body chemoreceptors. Perfusion of the carotid sinus with the retrogradely transported dye (Fluoro-Gold) labeled primary sensory neurons in petrosal ganglion. Numerous somata in the petrosal ganglion labeled with dye contained mRNAs for all the above peptides, except SOM. Moreover, TH mRNA was found in a substantial number of retrogradely labeled cells in the petrosal ganglion. This study provides information concerning which of the numerous peptides identified in sensory neurons of petrosal ganglion may be involved in modulation of the arterial baroreceptor and chemoreceptor reflexes. PMID:1681484

  13. 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.

  14. 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.

  15. Angiotensin II-superoxide-NFκB signaling and aortic baroreceptor dysfunction in chronic heart failure

    PubMed Central

    Zhang, Dongze; Muelleman, Robert L.; Li, Yu-Long

    2015-01-01

    Chronic heart failure (CHF) affects approximately 5.7 million people in the United States. Increasing evidence from both clinical and experimental studies indicates that the sensitivity of arterial baroreflex is blunted in the CHF state, which is a predictive risk factor for sudden cardiac death. Normally, the arterial baroreflex regulates blood pressure and heart rate through sensing mechanical alteration of arterial vascular walls by baroreceptor terminals in the aortic arch and carotid sinus. There are aortic baroreceptor neurons in the nodose ganglion (NG), which serve as the main afferent component of the arterial baroreflex. Functional changes of baroreceptor neurons are involved in the arterial baroreflex dysfunction in CHF. In the CHF state, circulating angiotensin II (Ang II) and local Ang II concentration in the NG are elevated, and AT1R mRNA and protein are overexpressed in the NG. Additionally, Ang II-superoxide-NFκB signaling pathway regulates the neuronal excitability of aortic baroreceptors through influencing the expression and activation of Nav channels in aortic baroreceptors, and subsequently causes the impairment of the arterial baroreflex in CHF. These new findings provide a basis for potential pharmacological interventions for the improvement of the arterial baroreflex sensitivity in the CHF state. This review summarizes the mechanisms responsible for the arterial baroreflex dysfunction in CHF. PMID:26528122

  16. Decreased excitability and voltage-gated sodium currents in aortic baroreceptor neurons contribute to the impairment of arterial baroreflex in cirrhotic rats.

    PubMed

    Lee, Choong-Ku; Park, Kwang-Hwa; Baik, Soon-Koo; Jeong, Seong-Woo

    2016-06-01

    Cardiovascular autonomic dysfunction, which is manifested by an impairment of the arterial baroreflex, is prevalent irrespective of etiology and contributes to the increased morbidity and mortality in cirrhotic patients. However, the cellular mechanisms that underlie the cirrhosis-impaired arterial baroreflex remain unknown. In the present study, we examined whether the cirrhosis-impaired arterial baroreflex is attributable to the dysfunction of aortic baroreceptor (AB) neurons. Biliary and nonbiliary cirrhotic rats were generated via common bile duct ligation (CBDL) and intraperitoneal injections of thioacetamide (TAA), respectively. Histological and molecular biological examinations confirmed the development of fibrosis in the livers of both cirrhotic rat models. The heart rate changes during phenylephrine-induced baroreceptor activation indicated that baroreflex sensitivity was blunted in the CBDL and TAA rats. Under the current-clamp mode of the patch-clamp technique, cell excitability was recorded in DiI-labeled AB neurons. The number of action potential discharges in the A- and C-type AB neurons was significantly decreased because of the increased rheobase and threshold potential in the CBDL and TAA rats compared with sham-operated rats. Real-time PCR and Western blotting indicated that the NaV1.7, NaV1.8, and NaV1.9 transcripts and proteins were significantly downregulated in the nodose ganglion neurons from the CBDL and TAA rats compared with the sham-operated rats. Consistent with these molecular data, the tetrodotoxin-sensitive NaV currents and the tetrodotoxin-resistant NaV currents were significantly decreased in A- and C-type AB neurons, respectively, from the CBDL and TAA rats compared with the sham-operated rats. Taken together, these findings implicate a key cellular mechanism in the cirrhosis-impaired arterial baroreflex. PMID:26984890

  17. 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.

  18. Arterial baroreceptor reflex control of renal sympathetic nerve activity following chronic myocardial infarction in male, female, and ovariectomized female rats.

    PubMed

    Pinkham, Maximilian I; Whalley, Gillian A; Guild, Sarah-Jane; Malpas, Simon C; Barrett, Carolyn J

    2015-07-15

    There is controversy regarding whether the arterial baroreflex control of renal sympathetic nerve activity (SNA) in heart failure is altered. We investigated the impact of sex and ovarian hormones on changes in the arterial baroreflex control of renal SNA following a chronic myocardial infarction (MI). Renal SNA and arterial pressure were recorded in chloralose-urethane anesthetized male, female, and ovariectomized female (OVX) Wistar rats 6-7 wk postsham or MI surgery. Animals were grouped according to MI size (sham, small and large MI). Ovary-intact females had a lower mortality rate post-MI (24%) compared with both males (38%) and OVX (50%) (P < 0.05). Males and OVX with large MI, but not small MI, displayed an impaired ability of the arterial baroreflex to inhibit renal SNA. As a result, the male large MI group (49 ± 6 vs. 84 ± 5% in male sham group) and OVX large MI group (37 ± 3 vs. 75 ± 5% in OVX sham group) displayed significantly reduced arterial baroreflex range of control of normalized renal SNA (P < 0.05). In ovary-intact females, arterial baroreflex control of normalized renal SNA was unchanged regardless of MI size. In males and OVX there was a significant, positive correlation between left ventricle (LV) ejection fraction and arterial baroreflex range of control of normalized renal SNA, but not absolute renal SNA, that was not evident in ovary-intact females. The current findings demonstrate that the arterial baroreflex control of renal SNA post-MI is preserved in ovary-intact females, and the state of left ventricular dysfunction significantly impacts on the changes in the arterial baroreflex post-MI. PMID:25994953

  19. Unilateral baroreceptor activation therapy: the beauty of asymmetry.

    PubMed

    de Leeuw, Peter W

    2015-01-01

    With respect to paired internal organs, we commonly think that these are symmetrical and have identical physiological functions. This, however, appears not to be the case. A particular organ where asymmetry comes to expression is the baroreceptor system. Clinical data in patients with resistant hypertension who are treated with device-based baroreceptor activation clearly show that there are functional differences between the left and the right baroreceptor systems. This has implications for our understanding of certain diseases. PMID:26106932

  20. 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.

  1. Baroreceptor reflex sensitivity in human neonates: the effect of postmenstrual age

    PubMed Central

    Andriessen, Peter; Oetomo, Sidarto Bambang; Peters, Chris; Vermeulen, Barbara; Wijn, Pieter FF; Blanco, Carlos E

    2005-01-01

    We performed a cross-sectional study in human infants to determine if indices of R–R interval variability, systolic blood pressure (SBP) variability, and baroreceptor reflex sensitivity change with postmenstrual age (PMA: gestational age + postnatal age). The electrocardiogram, arterial SBP and respiration were recorded in clinically stable infants (PMA, 28–42 weeks) in the quiet sleep state in the first days after birth. (Cross-)spectral analyses of R–R interval series and SBP series were performed to calculate the power of low-frequency (LF, indicating baroreceptor reflex activity, 0.04–0.15 Hz) and high-frequency (HF, indicating parasympathetic activity, individualized between the p-10 and p-90 values of respiratory frequency) fluctuations, and transfer function phase and gain. The mean R–R interval, and LF and HF spectral powers of R–R interval series increased with PMA. The mean SBP increased with PMA, but not the LF and HF spectral powers of SBP series. In the LF range, cross-spectral analysis showed high coherence values (> 0.5) with a consistent negative phase shift between R–R interval and SBP, indicating a ∼3 s lag in R–R interval changes in relation to SBP. Baroreceptor reflex sensitivity, calculated from LF transfer gain, increased significantly with PMA, from 5 (preterm) to 15 ms mmHg−1 (term). Baroreceptor reflex sensitivity correlated significantly with the (LF and) HF spectral powers of R–R interval series, but not with the LF and HF spectral powers of SBP series. The principal conclusions are that baroreceptor reflex sensitivity and spectral power in R–R interval series increase in parallel with PMA, suggesting a progressive vagal maturation with PMA. PMID:16051623

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. [Anesthesia management in implantation of baroreceptor stimulators].

    PubMed

    Werner, T; Lebar, L; Wittmann, S; Keyser, A; Fischer, M; Schmidli, J; Graf, B M; Zausig, Y A

    2015-09-01

    Baroreceptor stimulators are novel implantable devices that activate the carotid baroreceptor reflex. This results in a decrease in activity of the sympathetic nervous system and inhibition of the renin-angiotensin-aldosterone system. In patients with drug-resistant hypertension, permanent electrical activation of the baroreceptor reflex results in blood pressure reduction and cardiac remodeling. For correct intraoperative electrode placement at the carotid bifurcation, the baroreceptor reflex needs to be activated several times. Many common anesthetic agents, such as inhalation anesthetics and propofol dampen or inhibit the baroreceptor reflex and complicate or even prevent successful placement. Therefore, a specific anesthesia and pharmacological management is necessary to ensure successful implantation of baroreceptor reflex stimulators. PMID:26275386

  7. Differential distribution of voltage-gated channels in myelinated and unmyelinated baroreceptor afferents.

    PubMed

    Schild, John H; Kunze, Diana L

    2012-12-24

    Voltage gated ion channels (VGC) make possible the frequency coding of arterial pressure and the neurotransmission of this information along myelinated and unmyelinated fiber pathways. Although many of the same VGC isoforms are expressed in both fiber types, it is the relative expression of each that defines the unique discharge properties of myelinated A-type and unmyelinated C-type baroreceptors. For example, the fast inward Na⁺ current is a major determinant of the action potential threshold and the regenerative transmembrane current needed to sustain repetitive discharge. In A-type baroreceptors the TTX-sensitive Na(v)1.7 VGC contributes to the whole cell Na⁺ current. Na(v)1.7 is expressed at a lower density in C-type neurons and in conjunction with TTX-insensitive Na(v)1.8 and Na(v)1.9 VGC. As a result, action potentials of A-type neurons have firing thresholds that are 15-20 mV more negative and upstroke velocities that are 5-10 times faster than unmyelinated C-type neurons. A more depolarized threshold in conjunction with a broader complement of non-inactivating K(V) VGC subtypes produces C-type action potentials that are 3-4 times longer in duration than A-type neurons and at markedly lower levels of cell excitability. Unmyelinated baroreceptors also express KCa1.1 which provides approximately 25% of the total outward K⁺ current. KCa1.1 plays a critically important role in shaping the action potential profile of C-type neurons and strongly impacts neuronal excitability. A-type neurons do not functionally express the KCa1.1 channel despite having a whole cell Ca(V) current quite similar to that of C-type neurons. As a result, A-type neurons do not have the frequency-dependent braking forces of KCa1.1. Lack of a KCa current and only a limited complement of non-inactivating K(V) VGC in addition to a hyperpolarization activated HCN1 current that is nearly 10 times larger than in C-type neurons leads to elevated levels of discharge in A-type neurons, a

  8. 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.

  9. 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.

  10. 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)

  11. Inappropriate mediastinal baroreceptor reflex as a possible cause of sudden infant death syndrome - Is thorough burping before sleep protective?

    PubMed

    Flaig, Christian

    2007-01-01

    Despite extensive research, a link between the assumed mechanisms of death and known risk factors for sudden infant death syndrome (SIDS) has not yet been established. Modifiable risk factors such as prone sleeping position, nicotine exposure and thermal stress and non-avoidable risk factors like male gender and some risky socio-economic conditions could be detected, but the etiology of SIDS remains unknown. In many SIDS cases histopathological findings suggest an involvement of vital autonomic control functions and unidentified trigger factors seem to play a role. From a hypothetical point of view, a developmental sympatheticovagal imbalance of the cardiovascular reflex control could cause a predisposition for SIDS. An assumed gastroesophageal trigger impulse is possibly developed during the first weeks of life and could lead to the infant's vagal reflex death. Air swallowed during feeding escapes through the esophagus while the infant is sleeping. The temporarily bloated esophagus exerts pressure on neighboring mediastinal baroreceptors, which is potentially misinterpreted as a rise in arterial pressure. The following cardiodepressoric baroreceptor reflex could lead to arterial hypotension, bradycardia and cardiac arrest. Sleeping in prone position may create an increased thoracic pressure on mediastinal baroreceptors, causing a more pronounced vagal reflex and an increased likelihood of SIDS. Prone position in connection with soft objects in the infant's sleeping environment potentially generates an increased oculobulbar pressure, resulting in an additional cardiodepressoric condition (Aschner-Dagnini phenomenon). From the sixth month of life onwards the sympatheticovagal balance seems to have matured sufficiently to compensate the life-threatening challenges in most infants. Insufficient postprandial burping could either create another independent modifiable risk factor or present the missing link to a common trigger mechanism for SIDS. Further investigations

  12. Chronic inhibition of endothelial nitric oxide synthase activity in nucleus tractus solitarii enhances baroreceptor reflex in conscious rats

    PubMed Central

    Waki, Hidefumi; Kasparov, Sergey; Wong, Liang-Fong; Murphy, David; Shimizu, Tsuyoshi; Paton, Julian F R

    2003-01-01

    In acute experiments, we demonstrated previously that nitric oxide (NO) donors exogenously applied to the nucleus tractus solitarii (NTS) depressed the baroreceptor cardiac reflex. In this study, we determined a role for endogenous endothelial nitric oxide synthase (eNOS) activity in the NTS for chronically regulating baroreceptor reflex function in conscious rats. A recombinant adenoviral vector directing expression of a truncated form of eNOS was microinjected bilaterally into the NTS to inhibit endogenous eNOS activity. Arterial pressure was monitored continuously using radio-telemetry in freely moving animals and spontaneous baroreceptor reflex gain (sBRG) determined by a time-series method. sBRG showed a gradual increase from day 7 to 21 after gene transfer and the value at day 21 (1.68 ± 0.20 ms mmHg−1, n = 6) was significantly higher than that before gene transfer (1.13 ± 0.09 ms mmHg−1, P < 0.001). This value was also significantly higher than that in rats in which enhanced green fluorescent protein (eGFP) was expressed in the NTS (1.04 ± 0.21 ms mmHg−1; n = 6, P < 0.01) and saline-treated groups (1.12 ± 0.15 ms mmHg−1; n = 4, P < 0.05), which did not change from control levels. In addition, heart rate decreased from 336 ± 6 to 318 ± 8 b.p.m. (P < 0.05) 21 days after gene transfer. This value was also significantly lower than that in control groups (eGFP: 348 ± 9 b.p.m., n = 6, P < 0.01; saline: 347 ± 5 b.p.m., n = 4, P < 0.05). Gene transfer did not affect arterial pressure. These findings suggest that in the conscious rat eNOS is constitutively active within the NTS and is a factor regulating baroreceptor reflex gain and heart rate. PMID:12509491

  13. Arterial endothelial function measurement method and apparatus

    SciTech Connect

    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.

  14. 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

  15. 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

  16. Effects of acute and chronic baroreceptor denervation on diving responses in ducks.

    PubMed

    Smith, F M; Jones, D R

    1990-04-01

    To investigate the effects of barodenervation on the cardiovascular responses to forced submersion, we implanted snares around the aortic nerves innervating the baroreceptors in anesthetized (pentobarbital sodium, 35-45 mg/kg) ducks (Anas platyrhynchos). Snares were withdrawn 1 wk after surgery to effect barodenervation in the absence of complications from surgical trauma or anesthesia. After barodenervation, resting heart rate (HR), hind limb vascular resistance (HLVR), and mean arterial pressure (MAP) all increased, with different time courses, over the 16-day observation period. Bradycardia developed during forced submersion in ducks before and after barodenervation, although this response was reduced for 1-3 days after nerve section. The HR response to diving intensified 4-5 days after denervation, and the level of dive bradycardia at 16 days was similar to that before denervation. End-dive MAP fell further, as a proportion of predive MAP, with time after baroreceptor loss. The absolute level of HLVR reached during diving was unaffected by barodenervation. These results show that diving responses develop in the absence of baroreceptors, but MAP in the dive is not maintained as well in barodenervates as in baroreceptor-intact animals. PMID:2331033

  17. Functional arteries grown in vitro.

    PubMed

    Niklason, L E; Gao, J; Abbott, W M; Hirschi, K K; Houser, S; Marini, R; Langer, R

    1999-04-16

    A tissue engineering approach was developed to produce arbitrary lengths of vascular graft material from smooth muscle and endothelial cells that were derived from a biopsy of vascular tissue. Bovine vessels cultured under pulsatile conditions had rupture strengths greater than 2000 millimeters of mercury, suture retention strengths of up to 90 grams, and collagen contents of up to 50 percent. Cultured vessels also showed contractile responses to pharmacological agents and contained smooth muscle cells that displayed markers of differentiation such as calponin and myosin heavy chains. Tissue-engineered arteries were implanted in miniature swine, with patency documented up to 24 days by digital angiography. PMID:10205057

  18. Effect of simvastatin in the autonomic system is dependent on the increased gain/sensitivity of the baroreceptors

    PubMed Central

    Moreira, Edson D; Mostarda, Cristiano T; Moraes-Silva, Ivana C; Ferreira, Janaina B; dos Santos, Fernando; Lacchini, Silvia; De Angelis, Kátia; Rodrigues, Bruno; Irigoyen, Maria Cláudia

    2013-01-01

    A number of mechanisms have been proposed to explain the pleiotropic effect of statin therapy to reduce sympathetic outflow in cardiovascular disease. We tested the hypothesis that statin treatment could improve baroreflex gain-sensitivity triggered by morphological adaptations in the mechanoreceptor site, thus reducing sympathetic activity, regardless of arterial pressure (AP) level reduction. Male spontaneously hypertensive rats (SHR) were divided into control (SHR, n = 8) and SHR-simvastatin (5 mg/kg/day, for 7 days) (SHR-S, n = 8). After treatment, AP, baroreflex sensitivity (BRS) in response to AP-induced changes, aortic depressor nerve activity, and spectral analyses of pulse interval (PI) and AP variabilities were performed. Internal and external carotids were prepared for morphoquantitative evaluation. Although AP was similar between groups, sympathetic modulation, represented by the low frequency band of PI (SHR: 6.84 ± 3.19 vs. SHR-S: 2.41 ± 0.96 msec2) and from systolic AP variability (SHR: 3.95 ± 0.36 vs. SHR-S: 2.86 ± 0.18 mmHg2), were reduced in treated animals. In parallel, simvastatin induced an increase of 26% and 21% in the number of elastic lamellae as well as a decrease of 9% and 25% in the carotid thickness in both, external and internal carotid, respectively. Moreover, improved baroreceptor function (SHR: 0.78 ± 0.03 vs. SHR-S: 1.06 ± 0.04% mv/mmHg) was observed in addition to a 115% increase in aortic depressor nerve activity in SHR-S rats. Therefore, our data suggest that the reduction of sympathetic outflow in hypertension by simvastatin treatment may be triggered by structural changes in the carotid arteries and increased BRS in response to an improvement of the baroreceptors discharge and consequently of the afferent pathway of the baroreflex arch. PMID:24303130

  19. 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.

  20. 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.

  1. Sensitization of aortic and cardiac baroreceptors by arginine vasopressin in mammals.

    PubMed Central

    Abboud, F M; Aylward, P E; Floras, J S; Gupta, B N

    1986-01-01

    Vasopressin facilitates the baroreflex control of the circulation. The peptide may act at several sites to augment the baroreflex. In this study we examined the effect of vasopressin on aortic baroreceptors in anaesthetized rabbits and on left ventricular mechanoreceptors in anaesthetized cats. Vasopressin (16 mu./kg. min) did not change resting nerve discharge in single fibres from aortic baroreceptors. Vasopressin (16 mu./kg. min) significantly enhanced the response of single aortic nerve fibre discharge to elevation in arterial pressure. The slope relating nerve activity to mean arterial pressure increased from 0.24 +/- 0.05 (mean +/- S.E. of mean) to 0.50 +/- 0.16 impulses/cardiac cycle. mmHg (P less than 0.05) in ten aortic medullated fibres and from 0.06 +/- 0.03 to 0.18 +/- 0.04 impulses/cardiac cycle. mmHg (P less than 0.05) in three non-medullated fibres. Vasopressin (16 mu./kg. min) did not change resting nerve discharge in single fibres from left ventricular mechanoreceptors. Vasopressin (16 mu./kg. min) significantly enhanced the response of single nerve fibre discharge from left ventricular mechanoreceptors in response to elevation of left ventricular end-diastolic pressure. The slope relating nerve activity to left ventricular end-diastolic pressure increased from 0.24 +/- 0.07 to 0.32 +/- 0.07 impulses/cardiac cycle. mmHg (P less than 0.05) in six medullated fibres and from 0.10 +/- 0.01 to 0.15 +/- 0.02 impulses/cardiac cycle. mmHg (P less than 0.05) in four non-medullated fibres. These data show that vasopressin sensitizes high and low pressure baroreceptors and suggest a mechanism by which vasopressin may facilitate the baroreflex control of the circulation. PMID:3795090

  2. 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. PMID:26140618

  3. Plasma leptin inhibits the response of nucleus of the solitary tract neurons to aortic baroreceptor stimulation.

    PubMed

    Ciriello, John

    2013-08-01

    Leptin receptors have been identified within the nucleus of the solitary tract (NTS) and leptin injections into the caudal NTS inhibit the baroreceptor reflex. However, whether plasma leptin alters the discharge of NTS neurons mediating aortic baroreceptor reflex activity is not known. A series of electrophysiological single unit recording experiments was done in the urethane-chloralose anesthetized, paralyzed and artificially ventilated Wistar and Zucker obese rat with either their neuroaxis intact or with mid-collicular transections. Single units in NTS antidromically activated by electrical stimulation of depressor sites in the caudal ventrolateral medulla (CVLM) were found to display a cardiac cycle-related rhythmicity. These units were tested for their responses to stimulation of the aortic depressor nerve (ADN) and intra-carotid injections of leptin (50-200ng/0.1ml). Of 63 single units tested in NTS, 33 were antidromically activated by stimulation of CVLM depressor sites and 18 of these single units responded with a decrease in discharge rate after intracarotid injections of leptin. Thirteen of these leptin responsive neurons (∼72%) were excited by ADN stimulation. Furthermore, the excitatory response of these single units to ADN stimulation was attenuated by about 50% after the intracarotid leptin injection. Intracarotid injections of leptin (200ng/0.1ml) in the Zucker obese rat did not alter the discharge rate of NTS-CVLM projecting neurons. These data suggest that leptin exerts a modulatory effect on brainstem neuronal circuits that control cardiovascular responses elicited during the reflex activation of arterial baroreceptors. PMID:23792336

  4. Medullary raphe neurones and baroreceptor modulation of the respiratory motor pattern in the cat

    PubMed Central

    Lindsey, B G; Arata, A; Morris, K F; Hernandez, Y M; Shannon, R

    1998-01-01

    Perturbations of arterial blood pressure change medullary raphe neurone activity and the respiratory motor pattern. This study sought evidence for actions of baroresponsive raphe neurones on the medullary respiratory network.Blood pressure was perturbed by intravenous injection of an α1-adrenergic receptor agonist, unilateral pressure changes in the carotid sinus, or occlusion of the descending aorta in thirty-six Dial-urethane-anaesthetized, vagotomized, paralysed, artificially ventilated cats. Neurones were monitored with microelectrode arrays in two or three of the following domains: nucleus raphe obscurus-nucleus raphe pallidus, nucleus raphe magnus, and rostral and caudal ventrolateral medulla. Data were analysed with cycle-triggered histograms, peristimulus time and cumulative sum histograms, cross-correlograms and spike-triggered averages of efferent phrenic nerve activity.Prolongation of the expiratory phase and decreased peak integrated phrenic amplitude were most frequently observed. Of 707 neurones studied, 310 had altered firing rates during stimulation; changes in opposite directions were monitored simultaneously in fifty-six of eighty-seven data sets with at least two baroresponsive neurones.Short time scale correlations were detected between neurones in 347 of 3388 pairs. Seventeen pairs of baroresponsive raphe neurones exhibited significant offset correlogram features indicative of paucisynaptic interactions. In correlated raphe-ventrolateral medullary neurone pairs with at least one baroresponsive neurone, six of seven ventrolateral medullary decrementing expiratory (E-Decr) neurones increased their firing rate during baroreceptor stimulation. Thirteen of fifteen ventrolateral medullary inspiratory neurones correlated with raphe cells decreased their firing rate during baroreceptor stimulation.The results support the hypothesis that raphe neuronal assemblies transform and transmit information from baroreceptors to neurones in the ventral

  5. Cardiac hypertrophy and telemetered blood pressure 6 wk after baroreceptor denervation in normotensive rats.

    PubMed

    Van Vliet, B N; Hu, L; Scott, T; Chafe, L; Montani, J P

    1996-12-01

    We investigated cardiac morphometry 6 wk after sinoaortic baroreceptor denervation (SAD) in Long-Evans rats. SAD (n = 19) was associated with an 11% increase in the weight of the left ventricle (LV) plus septum (P < 0.001) and a 39% increase in that of the right ventricular (RV) free wall (P < 0.001), relative to sham-operated rats (n = 18). RV wall thickness was significantly increased in SAD animals, but there was no difference in the LV wall thickness and volumes of the RV and LV between groups. Constrictor responses to methoxamine and dilation responses to acetylcholine were assessed in an in vitro perfused mesenteric circulation preparation, but neither response was affected by SAD. Baroreceptor denervation was associated with marked and significant increases in the variability (2.8-fold) and daily peak (39 mmHg) levels of telemetered mean arterial pressure (MAP) and small (5%) but significant increases in the daily mean MAP level. Our results are consistent with an effect of increased MAP variability on ventricular weight but cannot rule out possible contributions from other mechanisms. PMID:8997380

  6. Static and dynamic changes in carotid artery diameter in humans during and after strenuous exercise

    PubMed Central

    Studinger, Péter; Lénárd, Zsuzsanna; Kováts, Zsuzsanna; Kocsis, László; Kollai, Mark

    2003-01-01

    Arterial baroreflex function is altered by dynamic exercise, but it is not clear to what extent baroreflex changes are due to altered transduction of pressure into deformation of the barosensory vessel wall. In this study we measured changes in mean common carotid artery diameter and the pulsatile pressure: diameter ratio (PDR) during and after dynamic exercise. Ten young, healthy subjects performed a graded exercise protocol to exhaustion on a bicycle ergometer. Carotid dimensions were measured with an ultrasound wall-tracking system; central arterial pressure was measured with the use of radial tonometry and the generalized transfer function; baroreflex sensitivity (BRS) was assessed in the post-exercise period by spectral analysis and the sequence method. Data are given as means ± s.e.m. Mean carotid artery diameter increased during exercise as compared with control levels, but carotid distension amplitude did not change. PDR was reduced from 27.3 ± 2.7 to 13.7 ± 1.0 μm mmHg−1. Immediately after stopping exercise, the carotid artery constricted and PDR remained reduced. At 60 min post-exercise, the carotid artery dilated and the PDR increased above control levels (33.9 ± 1.4 μm mmHg−1). The post-exercise changes in PDR were closely paralleled by those in BRS (0.74 ≤ r ≤ 0.83, P < 0.05). These changes in mean carotid diameter and PDR suggest that the mean baroreceptor activity level increases during exercise, with reduced dynamic sensitivity; at the end of exercise baroreceptors are suddenly unloaded, then at 1 h post-exercise, baroreceptor activity increases again with increasing dynamic sensitivity. The close correlation between PDR and BRS observed at post-exercise underlies the significance of mechanical factors in arterial baroreflex control. PMID:12766246

  7. 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

  8. [Ischemic white matter lesions may be caused by the baroreceptor reflex are dysfunction].

    PubMed

    Obi, T

    1995-08-01

    Muscle sympathetic nerve activity (MSNA, bursts/min) was recorded microneurographically from the tibial nerve in the control group (8 males and 8 females) and the cerebral infarction group (12 males and 12 females) with ischemic white matter lesions (WMLs) diagnosed on T2-weighted MR imaging. Subjects in the latter group were more hypertensive. A significant positive correlation between age and the MSNA at rest was detected in the control group, but not in the cerebral infarction group. The MSNA at rest was significantly low exclusively in infarcted females. Although the blood pressure did not decrease in either group during a 30 degrees head-up tilt, the MSNA was enhanced in the control group alone. On the cold pressor test, the control group demonstrated a significant pressor response, but not an increase in MSNA. In contrast, the cerebral infarction group showed a significant increase in MSNA, and, within the group, only infarcted females lacked a clear pressor response. These results indicated the existence of an insensitivity in the baroreceptor reflex arc on the part of infarcted males, as already indicated in hypertensive patients. On the other hand, on infarcted females, there were both a hypofunction of the baroreceptor reflex arc and a decline of the vascular reactivity, possibly due to an inadequate development of the sympathetic nervous system and a low level of estrogen. Interestingly mean WMLs%, which was calculated as total WMLs areas x 100/total subdural areas on four horizontal T2-weighted MR images, 10, 20, 30, 40 mm above the bicommisural plane, was significantly larger in infarcted females (8.7 +/- 0.7%, mean +/- S.E.) than males (5.1 +/- 0.7%). This discrepancy may be caused by the above-mentioned difference on the results between them. WMLs are mostly distributed in the watershed zone supplied by the long penetrating arteries. Therefore, the lesions may be produced by wide fluctuations in blood pressure as the result of a dysfunction of the

  9. Leptin in nucleus of the solitary tract alters the cardiovascular responses to aortic baroreceptor activation.

    PubMed

    Ciriello, John

    2013-06-01

    Recent data suggests that neurons expressing the long form of the leptin receptor form at least two distinct groups within the caudal nucleus of the solitary tract (NTS): a group within the lateral NTS (Slt) and one within the medial (Sm) and gelantinosa (Sg) NTS. Discrete injections of leptin into Sm and Sg, a region that receives chemoreceptor input, elicit increases in arterial pressure (AP) and renal sympathetic nerve activity (RSNA). However, the effect of microinjections of leptin into Slt, a region that receives baroreceptor input is unknown. Experiments were done in the urethane-chloralose anesthetized, paralyzed and artificially ventilated Wistar or Zucker obese rat to determine leptin's effect in Slt on heart rate (HR), AP and RSNA during electrical stimulation of the aortic depressor nerve (ADN). Depressor sites within Slt were first identified by the microinjection of l-glutamate (Glu; 0.25M; 10nl) followed by leptin microinjections. In the Wistar rat leptin microinjection (50ng; 20nl) into depressor sites within the lateral Slt elicited increases in HR and RSNA, but no changes in AP. Additionally, leptin injections into Slt prior to Glu injections at the same site or to stimulation of the ADN were found to attenuate the decreases in HR, AP and RSNA to both the Glu injection and ADN stimulation. In Zucker obese rats, leptin injections into NTS depressor sites did not elicit cardiovascular responses, nor altered the cardiovascular responses elicited by stimulation of ADN. Those data suggest that leptin acts at the level of NTS to alter the activity of neurons that mediate the cardiovascular responses to activation of the aortic baroreceptor reflex. PMID:23535030

  10. A single air dive reduces arterial endothelial function in man

    PubMed Central

    Brubakk, AO; Duplancic, D; Valic, Z; Palada, I; Obad, A; Bakovic, D; Wisloff, U; Dujic, Z

    2005-01-01

    During and after decompression from dives, gas bubbles are regularly observed in the right ventricular outflow tract. A number of studies have documented that these bubbles can lead to endothelial dysfunction in the pulmonary artery but no data exist on the effect of diving on arterial endothelial function. The present study investigated if diving or oxygen breathing would influence endothelial arterial function in man. A total of 21 divers participated in this study. Nine healthy experienced male divers with a mean age of 31 ± 5 years were compressed in a hyperbaric chamber to 280 kPa at a rate of 100 kPa min−1 breathing air and remaining at pressure for 80 min. The ascent rate during decompression was 9 kPa min−1 with a 7 min stop at 130 kPa (US Navy procedure). Another group of five experienced male divers (31 ± 6 years) breathed 60% oxygen (corresponding to the oxygen tension of air at 280 kPa) for 80 min. Before and after exposure, endothelial function was assessed in both groups as flow-mediated dilatation (FMD) by ultrasound in the brachial artery. The results were compared to data obtained from a group of seven healthy individuals of the same age who had never dived. The dive produced few vascular bubbles, but a significant arterial diameter increase from 4.5 ± 0.7 to 4.8 ± 0.8 mm (mean ± s.d.) and a significant reduction of FMD from 9.2 ± 6.9 to 5.0 ± 6.7% were observed as an indication of reduced endothelial function. In the group breathing oxygen, arterial diameter increased significantly from 4.4 ± 0.3 mm to 4.7 ± 0.3 mm, while FMD showed an insignificant decrease. Oxygen breathing did not decrease nitroglycerine-induced dilatation significantly. In the normal controls the arterial diameter and FMD were 4.1 ± 0.4 mm and 7.7 ± 0.2.8%, respectively. This study shows that diving can lead to acute arterial endothelial dysfunction in man and that oxygen breathing will increase arterial diameter after return to breathing air. Further studies

  11. A single air dive reduces arterial endothelial function in man.

    PubMed

    Brubakk, A O; Duplancic, D; Valic, Z; Palada, I; Obad, A; Bakovic, D; Wisloff, U; Dujic, Z

    2005-08-01

    During and after decompression from dives, gas bubbles are regularly observed in the right ventricular outflow tract. A number of studies have documented that these bubbles can lead to endothelial dysfunction in the pulmonary artery but no data exist on the effect of diving on arterial endothelial function. The present study investigated if diving or oxygen breathing would influence endothelial arterial function in man. A total of 21 divers participated in this study. Nine healthy experienced male divers with a mean age of 31 +/- 5 years were compressed in a hyperbaric chamber to 280 kPa at a rate of 100 kPa min(-1) breathing air and remaining at pressure for 80 min. The ascent rate during decompression was 9 kPa min(-1) with a 7 min stop at 130 kPa (US Navy procedure). Another group of five experienced male divers (31 +/- 6 years) breathed 60% oxygen (corresponding to the oxygen tension of air at 280 kPa) for 80 min. Before and after exposure, endothelial function was assessed in both groups as flow-mediated dilatation (FMD) by ultrasound in the brachial artery. The results were compared to data obtained from a group of seven healthy individuals of the same age who had never dived. The dive produced few vascular bubbles, but a significant arterial diameter increase from 4.5 +/- 0.7 to 4.8 +/- 0.8 mm (mean +/- s.d.) and a significant reduction of FMD from 9.2 +/- 6.9 to 5.0 +/- 6.7% were observed as an indication of reduced endothelial function. In the group breathing oxygen, arterial diameter increased significantly from 4.4 +/- 0.3 mm to 4.7 +/- 0.3 mm, while FMD showed an insignificant decrease. Oxygen breathing did not decrease nitroglycerine-induced dilatation significantly. In the normal controls the arterial diameter and FMD were 4.1 +/- 0.4 mm and 7.7 +/- 0.2.8%, respectively. This study shows that diving can lead to acute arterial endothelial dysfunction in man and that oxygen breathing will increase arterial diameter after return to breathing air. Further

  12. 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.

  13. Endothelial function and coronary artery disease.

    PubMed

    Kinlay, S; Libby, P; Ganz, P

    2001-08-01

    The endothelium produces a number of vasodilator and vasoconstrictor substances that not only regulate vasomotor tone, but also the recruitment and activity of inflammatory cells and the propensity towards thrombosis. Endothelial vasomotor function is a convenient way to assess these other functions, and is related to the long-term risk of cardiovascular disease. Lipids (particularly low density lipoprotein cholesterol) and oxidant stress play a major role in impairing these functions, by reducing the bioavailability of nitric oxide and activating pro-inflammatory signalling pathways such as nuclear factor kappa B. Biomechanical forces on the endothelium, including low shear stress from disturbed blood flow, also activate the endothelium increasing vasomotor dysfunction and promoting inflammation by upregulating pro-atherogenic genes. In contrast, normal laminar shear stress promotes the expression of genes that may protect against atherosclerosis. The sub-cellular structure of endothelial cells includes caveolae that play an integral part in regulating the activity of endothelial nitric oxide synthase. Low density lipoprotein cholesterol and oxidant stress impair caveolae structure and function and adversely affect endothelial function. Lipid-independent pathways of endothelial cell activation are increasingly recognized, and may provide new therapeutic targets. Endothelial vasoconstrictors, such as endothelin, antagonize endothelium-derived vasodilators and contribute to endothelial dysfunction. Some but not all studies have linked certain genetic polymorphisms of the nitric oxide synthase enzyme to vascular disease and impaired endothelial function. Such genetic heterogeneity may nonetheless offer new insights into the variability of endothelial function. PMID:11507322

  14. Gadolinium inhibits mechanoelectrical transduction in rabbit carotid baroreceptors. Implication of stretch-activated channels.

    PubMed Central

    Hajduczok, G; Chapleau, M W; Ferlic, R J; Mao, H Z; Abboud, F M

    1994-01-01

    Gadolinium (Gd3+) has been shown to prevent mechanoelectrical transduction believed to be mediated through stretch-activated channels. We investigated the possible role of Gd(3+)-sensitive channels in mediating baroreceptor activity in the carotid sinus of rabbits. Baroreceptor activity induced by a ramp increase of carotid sinus pressure was reduced significantly during exposure to Gd3+. The inhibition was dose-related and reversible, and was not associated with alteration of carotid sinus wall mechanics as the pressure-strain relationship was unaffected. Veratrine triggered action potentials from single- and multiple-baroreceptor fibers when their response to pressure was inhibited by Gd3+. This suggests that the effect of Gd3+ on baroreceptors in the isolated carotid sinus was specific to their mechanical activation. The results suggest that stretch-activated ion channels sensitive to Gd3+ may be the mechanoelectrical transducers of rabbit carotid sinus baroreceptors. PMID:7527431

  15. From anatomy to function: diagnosis of atherosclerotic renal artery stenosis.

    PubMed

    Odudu, Aghogho; Vassallo, Diana; Kalra, Philip A

    2015-12-01

    Atherosclerotic renal artery stenosis (ARAS) affects 7% of the over 65 s and will be increasingly common with an ageing population. ARAS obstructs normal renal perfusion with adverse renal and cardiovascular consequences. Drug therapy is directed at reducing atherosclerotic risk. Two recent major trials of revascularization for ARAS showed that clinical outcomes were not improved beyond those offered by optimal drug therapy in most patients. This reflects experimental data showing that restoration of blood flow alone may not attenuate a cascade of tissue injury. A shift from anatomic to functional imaging of ARAS coupled to novel therapies might improve clinical outcomes in selected patients. This review outlines the case for separately assessing hemodynamic significance of arterial stenosis and functional reserve of renal parenchymal tissue. The authors consider current and emerging diagnostic techniques for ARAS and their potential to allow individualized and functionally directed treatments. PMID:26480218

  16. Arterial Compliance and Autonomic Functions in Adult Male Smokers

    PubMed Central

    Saxena, Yogesh; Gupta, Rani

    2016-01-01

    Introduction Smoking is known to augment sympathetic activity and may lead to increased arterial stiffness. Several studies have reported association of increased sympathetic activity and arterial stiffness to cardiovascular risks among smokers. Pulse Wave Velocity (PWV) of peripheral arteries, instead of aorta can be used as a non-invasive indicator of arterial stiffness. Aim To measure non-invasively, the autonomic functions and peripheral arterial stiffness in smokers, and to find out whether the aforementioned factors are modified by the level of physical activity in these smokers. Materials and Methods This cross-sectional analytical study was conducted in the Department of Physiology, HIMS, Dehradun, over a period of 12 months (2013-2014) on 100 adult males (20-40 years); 50 smokers and 50 non-smokers. The parameters analysed include relevant anthropometric and cardiovascular parameters, Pulse Wave Velocity (PWV), sustained Hand Grip Test (HGT) and Heart Rate Variability (HRV) domains. Data interpretation and analysis was carried out using SPSS 17.0. Comparison of the above mentioned parameters amongst groups was done with unpaired t-test. The relationship of pack-years & physical activity with vascular functions was assessed by Pearson’s correlation. Interaction of various grades of smoking and physical activity with Cardiovascular System (CVS) parameters was assessed by one-way ANOVA. Results Smokers had higher values of PWV (5.7±0.5m/s) as compared to non-smokers (4.8±0.4m/s) (p<0.001). ΔDBP during HGT was lower (7±3.18mmHg) among smokers as compared to non-smokers (19.4±3.5mmHg) (p<0.001). Smoking (pack-years) was positively related to PWV (r= .03) but showed a weak negative relationship with change in Diastolic Blood Pressure (ΔDBP) (r= -0.084, p=0.56) showing that, more the frequency of smoking, the more was arterial stiffening and the lesser was the sympathetic response to the HGT. The smokers had significantly higher sympathetic activity; Low

  17. Effects of Bariatric Surgery on Human Small Artery Function

    PubMed Central

    Aghamohammadzadeh, Reza; Greenstein, Adam S.; Yadav, Rahul; Jeziorska, Maria; Hama, Salam; Soltani, Fardad; Pemberton, Phil W.; Ammori, Basil; Malik, Rayaz A.; Soran, Handrean; Heagerty, Anthony M.

    2013-01-01

    Objectives The aim of this study was to investigate the effects of bariatric surgery on small artery function and the mechanisms underlying this. Background In lean healthy humans, perivascular adipose tissue (PVAT) exerts an anticontractile effect on adjacent small arteries, but this is lost in obesity-associated conditions such as the metabolic syndrome and type II diabetes where there is evidence of adipocyte inflammation and increased oxidative stress. Methods Segments of small subcutaneous artery and perivascular fat were harvested from severely obese individuals before (n = 20) and 6 months after bariatric surgery (n = 15). Small artery contractile function was examined in vitro with wire myography, and perivascular adipose tissue (PVAT) morphology was assessed with immunohistochemistry. Results The anticontractile activity of PVAT was lost in obese patients before surgery when compared with healthy volunteers and was restored 6 months after bariatric surgery. In vitro protocols with superoxide dismutase and catalase rescued PVAT anticontractile function in tissue from obese individuals before surgery. The improvement in anticontractile function after surgery was accompanied by improvements in insulin sensitivity, serum glycemic indexes, inflammatory cytokines, adipokine profile, and systolic blood pressure together with increased PVAT adiponectin and nitric oxide bioavailability and reduced macrophage infiltration and inflammation. These changes were observed despite the patients remaining severely obese. Conclusions Bariatric surgery and its attendant improvements in weight, blood pressure, inflammation, and metabolism collectively reverse the obesity-induced alteration to PVAT anticontractile function. This reversal is attributable to reductions in local adipose inflammation and oxidative stress with improved adiponectin and nitric oxide bioavailability. PMID:23665100

  18. 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

  19. Carotid Baroreceptor Stimulation and Arteriovenous Shunts for Resistant Hypertension.

    PubMed

    Paivanas, Nicholas; Bisognano, John D; Gassler, John P

    2015-01-01

    Pharmacologic therapy for hypertension is effective for the majority of patients with hypertension, but there is a subset of the population with treatment-resistant hypertension who cannot achieve their blood pressure goal despite taking multiple medications. Since these patients are at increased risk of cardiovascular disease and end-organ damage, additional therapies must be considered. This review discusses several novel interventional therapies-including baroreflex activation therapy, baroreceptor stenting, and creation of an arteriovenous shunt-that may provide alternative options for blood pressure control in those with treatment-resistant hypertension. All of these therapies remain investigational, and each has its own strengths and weaknesses that will be critical to assess as they come to market. PMID:27057291

  20. Predictive Value of Endothelial Function by Non-invasive Peripheral Arterial Tonometry for Coronary Artery Disease

    PubMed Central

    Matsuzawa, Yasushi; Li, Jing; Aoki, Tatsuo; Guddeti, Raviteja R.; Kwon, Taek-Geun; Cilluffo, Rebecca; Widmer, R. Jay.; Gulati, Rajiv; Lennon, Ryan J.; Lerman, Lilach O.; Lerman, Amir

    2014-01-01

    Background Endothelial dysfunction is a key step in the initiation and progression of atherosclerosis and subsequent cardiovascular complications. We examined whether peripheral endothelial function, as assessed by fingertip reactive hyperemia-peripheral arterial tonometry (RH-PAT) can provide additional clinical value to traditional risk factors for cardiovascular diseases in predicting coronary artery disease (CAD). Methods We included 118 stable patients who were referred for coronary angiography for chest pain evaluation or abnormal stress test. A natural logarithmic value of RH-PAT index (Ln_RHI) was obtained before cardiac catheterization by an independent operator. Significant CAD was defined as luminal stenosis ≥70% (≥50% at left main) and/or fractional flow reserve ≤0.80 in one or more major coronary arteries or their major branches. Results Levels of Ln_RHI were significantly lower in patients with CAD (n=60) compared to patients without CAD (n=58) (0.69±0.29 vs. 0.88±0.27, p<0.001). Ln_RHI was significantly associated with CAD independent from traditional risk factors (odds ratio [OR] for 0.1 decrease in Ln_RHI 1.25, 95% confidence interval [CI] 1.04 to 1.52, p=0.01). The net reclassification index was improved when Ln_RHI was added to traditional risk factors (0.62, 95% CI: 0.27 to 0.97, p=0.001). Conclusions Peripheral endothelial function, as assessed by RH-PAT, improved risk stratification when added to traditional risk factors. RH-PAT is potentially useful for identifying patients at high risk for CAD. PMID:25503420

  1. 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

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

    PubMed

    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

  3. 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

  4. Phrenic and diaphragm function after coronary artery bypass grafting.

    PubMed Central

    Estenne, M; Yernault, J C; De Smet, J M; De Troyer, A

    1985-01-01

    We studied respiratory mechanics and phrenic nerve and diaphragm function in 12 patients on the day before and eight to 13 days after coronary artery bypass grafting. The average vital capacity, functional residual capacity, and total lung capacity decreased by 20.5%, 9.5%, and 14.7% respectively after operation. Eleven patients showed less negative maximum inspiratory mouth pressures at any given lung volume after surgery and the magnitude of the change correlated with the reduction in total lung capacity. In 11 of the 12 patients the conduction times of the right and left phrenic nerves did not change substantially after operation and the ratio of inspiratory electrical activity (Edi) of left and right hemidiaphragms was similar before and after the procedure. One patient, however, showed a considerable increase in left phrenic nerve conduction time and a reduction in the left to right Edi ratio postoperatively. In three patients diaphragm function was also assessed by changes in transdiaphragmatic pressure during supramaximal phrenic nerve stimulation and voluntary increase in inspired volume; in none of the three patients did the transdiaphragmatic pressure swings show any significant change in the postoperative period. These data indicate that phrenic nerve paralysis only occasionally accounts for the postoperative loss of lung volume after coronary artery bypass grafting surgery. The mechanism of these abnormalities therefore remains to be determined. PMID:3875161

  5. Congestive cardiac failure: central role of the arterial blood pressure.

    PubMed Central

    Harris, P

    1987-01-01

    A review of the history of our knowledge and understanding of the peripheral oedema of congestive cardiac failure points to the conclusion that an inability of the heart to maintain the arterial pressure is of central importance in this condition. Although the function of the circulation is to perfuse the tissues, the body monitors the adequacy of its perfusion, not not through metabolic messengers carried from the tissues in the blood stream, but by sensing the arterial pressure; and the mechanisms evoked act to maintain the arterial pressure. In the short term this is achieved by autonomic regulation of the heart and blood vessels; in the longer term the arterial pressure is maintained through an increase in the blood volume by a retention of salt and water by the kidney. To support the latter process, intrinsic renal mechanisms are successively magnified by the renin-angiotensin-aldosterone system and by the activities of the sympathetic system and vasopressin. The natriuretic influence mediated through volume receptors and the release of atrial peptide is overruled by the arterial baroreceptors, so that the body maintains the arterial pressure at the expense of an increase in blood volume. In these ways the syndrome of congestive cardiac failure may be regarded as one which arises when the heart becomes chronically unable to maintain an appropriate arterial pressure without support. PMID:3311096

  6. Beneficial effects of lifelong caloric restriction on endothelial function are greater in conduit arteries compared to cerebral resistance arteries.

    PubMed

    Walker, Ashley E; Henson, Grant D; Reihl, Kelly D; Nielson, Elizabeth I; Morgan, R Garrett; Lesniewski, Lisa A; Donato, Anthony J

    2014-04-01

    Endothelial dysfunction occurs in conduit and cerebral resistance arteries with advancing age. Lifelong caloric restriction (CR) can prevent the onset of age-related dysfunction in many tissues, but its effects on cerebral resistance artery function, as compared with conduit artery function, have not been determined. We measured endothelium-dependent dilation (EDD) in the carotid artery and middle cerebral artery (MCA) from young (5-7 months), old ad libitum fed (AL, 29-32 months), and old lifelong CR (CR, 40 % CR, 29-32 months) B6D2F1 mice. Compared with young, EDD for old AL was 24 % lower in the carotid and 47 % lower in the MCA (p < 0.05). For old CR, EDD was not different from young in the carotid artery (p > 0.05), but was 25 % lower than young in the MCA (p < 0.05). EDD was not different between groups after NO synthase inhibition with N(ω)-nitro-L-arginine methyl ester in the carotid artery or MCA. Superoxide production by the carotid artery and MCA was greater in old AL compared with young and old CR (p < 0.05). In the carotid, incubation with the superoxide scavenger TEMPOL improved EDD for old AL (p > 0.05), with no effect in young or old CR (p > 0.05). In the MCA, incubation with TEMPOL or the NADPH oxidase inhibitor apocynin augmented EDD in old AL (p < 0.05), but reduced EDD in young and old CR (p < 0.05). Thus, age-related endothelial dysfunction is prevented by lifelong CR completely in conduit arteries, but only partially in cerebral resistance arteries. These benefits of lifelong CR on EDD result from lower oxidative stress and greater NO bioavailability. PMID:24065292

  7. 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.

  8. Improvement of renal function after opening occluded atherosclerotic renal arteries.

    PubMed

    Kanamori, Hiroshi; Toma, Masanao; Fukatsu, Atsushi

    2009-09-01

    Percutaneous transluminal renal angioplasty (PTRA) with stenting has been effective in the control of hypertension, renal function and pulmonary edema caused by atherosclerotic renal artery stenosis (ARAS). However, concerning the viability of renal function, this procedure has not been fully established, especially in the presence of renal atrophy or severe renal parenchymal disease. We report a dramatically improved case of acute renal failure caused by acute worsening ARAS treated by stenting. A 72-year-old female was admitted for accelerated renal dysfunction (serum ceatinine; 1.2-2.3 mg/dl) and hypertension (190/100 mmHg). At 10 days after admission, the patient's serum ceatinine increased to 6.7 mg/dl, her pulmonary edema was exaggerated and hemodialysis was required. Ultrasonography showed bilateral high-echoic kidneys, but no apparent finding of renal artery stenosis (RAS). At day 15, computed tomographic angiography indicated bilateral ostial RAS. Renal angiography demonstrated total occlusion of the right and severe (90%) disease in the left. ARAS was diagnosed by intravascular ultrasonography. The guidewire was inserted in both renal arteries, PTRA with stenting was performed in the right and a stent was directly implanted in the left. Immediately, each kidney enlarged to almost normal size, leading to satisfactory urination. She was released from hemodialysis the next day since her serum creatinine was normal and the pulmonary edema was improved. Although there is still no reliable prognostic factor including resistive index or kidney size, it is important that PTRA with stenting in ARAS should be considered in a case of accelerated renal dysfunction because of the possible improvement. PMID:19726830

  9. 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.

  10. Direct Characterization of Arterial Input Functions by Fluorescence Imaging of Exposed Carotid Artery to Facilitate Kinetic Analysis

    PubMed Central

    Elliott, Jonathan T.; Tichauer, Kenneth M.; Samkoe, Kimberley S.; Gunn, Jason R.; Sexton, Kristian J.; Pogue, Brian W.

    2014-01-01

    Purpose With the goal of facilitating tracer kinetic analysis in small-animal planar fluorescence imaging, an experimental method for characterizing tracer arterial input functions is presented. The proposed method involves exposing the common carotid arteries by surgical dissection, which can then be imaged directly during tracer injection and clearance. Procedures Arterial concentration curves of IRDye-700DX-carboxylate, IRDye-800CW-EGF, and IRDye-800CW conjugated to anti-EGFR Affibody are recovered from athymic female mice (n=12) by directly imaging exposed vessels. Images were acquired with two imaging protocols: a slow-kinetics approach (temporal resolution=45 s) to recover the arterial curves from two tracers simultaneously, and a fast-kinetics approach (temporal resolution=500 ms) to characterize the first-pass peak of a single tracer. Arterial input functions obtained by the carotid imaging technique, as well as plasma curves measured by blood sampling were fit with a biexponential pharmacokinetic model. Results Pharmacological fast- and slow-phase rate constants recovered with the proposed method were 0.37±0.26 and 0.007±0.001 min−1, respectively, for the IRDye700DX-C. For the IRDye800CW-EGF, the rate constants were 0.11±0.13 and 0.003±0.002 min−1. These rate constants did not differ significantly from those calculated previously by blood sampling, as determined by an F test; however, the between-subject variability was four times lower for arterial curves recovered using the proposed technique, compared with blood sampling. Conclusions The proposed technique enables the direct characterization of arterial input functions for kinetic analysis. As this method requires no additional instrumentation, it is immediately deployable in commercially available planar fluorescence imaging systems. PMID:24420443

  11. 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.

  12. Vascular endothelial function of patients with stable coronary artery disease

    PubMed Central

    Wang, Zhe; Yang, Xinchun; Cai, Jun; Shi, Hui; Zhong, Guangzhen; Chi, Hongjie

    2015-01-01

    Objectives: To evaluate vascular endothelial function and contributing factors in coronary heart disease (CHD) patients. Methods: One hundred twenty six CHD outpatients were randomly recruited. Reactive hyperemia index (RHI) <1.67 indicates endothelial dysfunction. Correlation between RHI and different biochemical parameters was evaluated. Results: RHI in patients receiving statins treatment was significantly higher than patients without statins treatment (P<0.05). RHI in patients with more than 3 risk factors for CHD was also markedly lower than that in patients with ≤2 risk factors (P<0.05). Patients with lesions at several branches of coronary artery had a markedly lower RHI when compared with those with coronary lesions at a single branch (P<0.05). For patients without statins treatment, RHI increased significantly after statins treatment for 1 month (P=0.01). In patients with endothelial dysfunction, FBG, HbA1C, hs-CRP and Hcy were significantly higher than those in patients with normal endothelial function (P<0.05 for all). Smokers with CHD had a remarkably lower RHI when compared with non-smokers (P<0.05). Conclusions: Smoking, FBG, HbA1C, Hcy and hs-CRP are significantly associated with endothelial dysfunction. Endothelial dysfunction is also related to the numbers of risk factors for CHD, degree of coronary lesions and statins. Statins treatment may significantly improve the endothelial function of CHD patients. PMID:26150839

  13. [Modern morpho-functional concepts in cephalic arterial distribution].

    PubMed

    Scutariu, M D; Ciupilan, Corina

    2005-01-01

    The present paper provides a general morphofunctional study of the oro-maxillary-facial cephalic arterial area that shows some particular hemodynamic characteristics. The internal maxillary artery supplies a very large territory, with numerous and wide anastomoses. In order to understand the hemodynamic characteristics of this artery, we analyzed some older theories, such as: Ludwig von Bertalanffy's General Systems Theory, Walter Zimmermann's Telome Theory, and some general rheological principles also. PMID:16607795

  14. 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

  15. Dynamic Susceptibility Contrast MRI with Localized Arterial Input Functions

    PubMed Central

    Lee, J.J.; Bretthorst, G.L.; Derdeyn, C.P.; Powers, W.J.; Videen, T.O.; Snyder, A.Z.; Markham, J.; Shimony, J.S.

    2010-01-01

    Compared to gold-standard measurements of cerebral perfusion with positron emission tomography (PET) using H2[15O] tracers, measurements with dynamic susceptibility contrast (DSC) MR are more accessible, less expensive and less invasive. However, existing methods for analyzing and interpreting data from DSC MR have characteristic disadvantages that include sensitivity to incorrectly modeled delay and dispersion in a single, global arterial input function (AIF). We describe a model of tissue microcirculation derived from tracer kinetics which estimates for each voxel a unique, localized AIF (LAIF). Parameters of the model were estimated using Bayesian probability theory and Markov-chain Monte Carlo, circumventing difficulties arising from numerical deconvolution. Applying the new method to imaging studies from a cohort of fourteen patients with chronic, atherosclerotic, occlusive disease showed strong correlations between perfusion measured by DSC MR with LAIF and perfusion measured by quantitative PET with H2[15O]. Regression to PET measurements enabled conversion of DSC MR to a physiological scale. Regression analysis for LAIF gave estimates of a scaling factor for quantitation which described perfusion accurately in patients with substantial variability in hemodynamic impairment. PMID:20432301

  16. [Functional-anatomical prerequisites of revascularization of the femoro-popliteal arterial segment].

    PubMed

    Losev, R Z; Nikolenko, V N; Mikul'skaia, E G; Eliseev, A A; Burov, Iu A

    2008-01-01

    Improved results of surgical treatment of patients with critical ischemia of lower extremities can be obtained by using the collateral bed. The condition of the profound femoral artery and the popliteal artery, especially in the zone of its trifurcation, is of the greatest significance for the decision on the volume of surgery. The carrying capacity of the collateral bed of the profound femoral artery in occlusion of the femoral artery was on average 284 ml/min. A positive prognostic criterion of recovered circulation in the extremity using the profound femoral artery is preservation of the patent trifurcation of the popliteal artery and/or the anterior tibial artery. The blood flow volume along the profound femoral artery under the given functional-anatomical conditions should be not less than 150 ml/min. Semiclosed loop endarterectomy of the superficial femoral and popliteal arteries with multilevel lesions of the lower extremity arteries allows the main zones of the collateral bed of the femoro-popliteal-tibial segment to be included in the blood flow. PMID:18411661

  17. 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.

  18. Assessments of Arterial Stiffness and Endothelial Function Using Pulse Wave Analysis

    PubMed Central

    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. PMID:22666595

  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. 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

  1. 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. PMID:17077312

  2. 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.

  3. 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

  4. 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

  5. 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. PMID:27160198

  6. Poor left ventricular function is not a contraindication for robotic totally endoscopic coronary artery bypass grafting.

    PubMed

    Rehman, Atiq; Garcia, Jose; Deshpande, Seema; Fitzpatrick, Mollie; Odonkor, Patrick; Zimrin, David; Griffith, Bartley; Bonatti, Johannes

    2009-06-01

    Robotic technology has enabled performance of totally endoscopic coronary artery bypass grafting (TECABG). Published series on TECABG were primarily performed in low-risk patients, and little is known about the outcome after totally endoscopic coronary surgery in patients with severely impaired left ventricular function. We report successful endoscopic placement of a left internal mammary artery bypass graft to the left anterior descending artery using the daVinci robotic system in a patient with a severely reduced left ventricular ejection fraction. PMID:19546067

  7. 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.

  8. Rab25 influences functional Cav1.2 channel surface expression in arterial smooth muscle cells.

    PubMed

    Bannister, John P; Bulley, Simon; Leo, M Dennis; Kidd, Michael W; Jaggar, Jonathan H

    2016-06-01

    Plasma membrane-localized CaV1.2 channels are the primary calcium (Ca(2+)) influx pathway in arterial smooth muscle cells (myocytes). CaV1.2 channels regulate several cellular functions, including contractility and gene expression, but the trafficking pathways that control the surface expression of these proteins are unclear. Similarly, expression and physiological functions of small Rab GTPases, proteins that control vesicular trafficking in arterial myocytes, are poorly understood. Here, we investigated Rab proteins that control functional surface abundance of CaV1.2 channels in cerebral artery myocytes. Western blotting indicated that Rab25, a GTPase previously associated with apical recycling endosomes, is expressed in cerebral artery myocytes. Immunofluorescence Förster resonance energy transfer (immunoFRET) microscopy demonstrated that Rab25 locates in close spatial proximity to CaV1.2 channels in myocytes. Rab25 knockdown using siRNA reduced CaV1.2 surface and intracellular abundance in arteries, as determined using arterial biotinylation. In contrast, CaV1.2 was not located nearby Rab11A or Rab4 and CaV1.2 protein was unaltered by Rab11A or Rab4A knockdown. Rab25 knockdown resulted in CaV1.2 degradation by a mechanism involving both lysosomal and proteasomal pathways and reduced whole cell CaV1.2 current density but did not alter voltage dependence of current activation or inactivation in isolated myocytes. Rab25 knockdown also inhibited depolarization (20-60 mM K(+)) and pressure-induced vasoconstriction (myogenic tone) in cerebral arteries. These data indicate that Rab25 is expressed in arterial myocytes where it promotes surface expression of CaV1.2 channels to control pressure- and depolarization-induced vasoconstriction. PMID:27076616

  9. Functional Prostacyclin Synthase Promoter Polymorphisms. Impact in Pulmonary Arterial Hypertension

    PubMed Central

    Cornelius, Amber R.; Lu, Xiao; Conklin, David S.; Del Rosario, Mark J.; Lowe, Anita M.; Elos, Mihret T.; Fettig, Lynsey M.; Wong, Randall E.; Hara, Naoko; Cogan, Joy D.; Phillips, John A.; Taylor, Matthew R.; Graham, Brian B.; Tuder, Rubin M.; Loyd, James E.; Geraci, Mark W.

    2014-01-01

    Rationale: Pulmonary arterial hypertension (PAH) is a progressive disease characterized by elevated pulmonary artery pressure, vascular remodeling, and ultimately right ventricular heart failure. PAH can have a genetic component (heritable PAH), most often through mutations of bone morphogenetic protein receptor 2, and idiopathic and associated forms. Heritable PAH is not completely penetrant within families, with approximately 20% concurrence of inactivating bone morphogenetic protein receptor 2 mutations and delayed onset of PAH disease. Because one of the treatment options is using prostacyclin analogs, we hypothesized that prostacyclin synthase promoter sequence variants associated with increased mRNA expression may play a protective role in the bone morphogenetic protein receptor 2 unaffected carriers. Objectives: To characterize the range of prostacyclin synthase promoter variants and assess their transcriptional activities in PAH-relevant cell types. To determine the distribution of prostacyclin synthase promoter variants in PAH, unaffected carriers in heritable PAH families, and control populations. Methods: Polymerase chain reaction approaches were used to genotype prostacyclin synthase promoter variants in more than 300 individuals. Prostacyclin synthase promoter haplotypes’ transcriptional activities were determined with luciferase reporter assays. Measurements and Main Results: We identified a comprehensive set of prostacyclin synthase promoter variants and tested their transcriptional activities in PAH-relevant cell types. We demonstrated differences of prostacyclin synthase promoter activities dependent on their haplotype. Conclusions: Prostacyclin synthase promoter sequence variants exhibit a range of transcriptional activities. We discovered a significant bias for more active prostacyclin synthase promoter variants in unaffected carriers as compared with affected patients with PAH. PMID:24605778

  10. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  12. 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

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

    2015-10-01

    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

  13. Reduced baroreceptor sensitivity during hypotension in ANP-knockout mice.

    PubMed

    Ackermann, U; Deliva, R D

    2001-03-01

    We studied baroreflex gain in inactin-anesthetized mice that had been genetically modified to be depleted of atrial natriuretic peptide (ANP -/-). Wild-type mice (ANP +/+) served as controls. ANP -/- mice had a significantly higher basal arterial blood pressure (ABP) than ANP +/+ mice [112+/-7 vs. 80+/-5 mmHg (mean +/- SEM)]. Their basal heart rates were not different (491+/-13 vs. 446+/-19 bpm). A third group, composed of ANP +/+ mice only, was rendered acutely hypertensive by an intravenous infusion of arginine vasopressin acetate (0.3 pg bolus followed by 0.3 pg/h) so as to serve as a control for the elevated ABP in the ANP -/- mice. Transient changes in ABP were caused by bolus injections of oxymetazoline hydrochloride (1.5-3 ng) or sodium nitroprusside (20-100 ng). Baroreflex gain was calculated as the ratio of the peak heart rate change that followed the peak change in mean ABP resulting from injection of oxymetazoline or nitroprusside. There were no significant differences among the groups in their responses to transient hypertension. On the other hand, the ANP -/- mice showed a significantly depressed tachycardic response to transient hypotension when compared with the other two groups. We conclude that the ANP -/- mice are unable to increase efferent sympathetic nervous activity adequately above the high basal activity that is a feature of this animal model. PMID:11294595

  14. 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.

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

    PubMed

    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

    2016-06-01

    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 less than 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

  16. 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

  17. Off-pump versus on-pump coronary artery revascularization: effects on pulmonary function.

    PubMed

    e Silva, Ana M R P; Saad, Roberto; Stirbulov, Roberto; Rivetti, Luiz A

    2010-07-01

    Many studies have shown important changes in lung function tests after coronary artery surgeries. It is controversial if off-pump surgery can give a better and shorter recovery than the on-pump. A prospective study was conducted on 42 patients submitted to coronary artery surgery and divided into two groups: 21 off-pump using intraluminal shunt (G (I)) and 21 on-pump (G (II)), matched by the anatomical location of the coronary arteries lesions. All patients had spirometric evaluation, blood gas measurements and alveolo-arterial oxygen gradient (A-aDO(2)), at the fourth and 10th postoperative days (PO(4) and PO(10)). Preoperatively, G(I) and G(II) had similar results (P>0.372). Spirometry showed decreases at PO(4) and remained decreased until PO(10) for both groups, with significant differences between the groups. The blood gas measurements showed reduction in arterial oxygen pressure (PaO(2)) and carbon dioxide pressure (PaCO(2)), while there was an increase in A-aDO(2) at PO(4) and PO(10) in both groups. The results suggest that different changes occur in pulmonary function when the surgery is performed with or without cardiopulmonary bypass. The off-pump patients showed significantly greater improvement than the on-pump group. PMID:20403972

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Muscle metaboreceptors modulate postexercise sweating, but not cutaneous blood flow, independent of baroreceptor loading status.

    PubMed

    Paull, Gabrielle; Dervis, Sheila; McGinn, Ryan; Haqani, Baies; Flouris, Andreas D; Kondo, Narihiko; Kenny, Glen P

    2015-12-01

    We examined whether sustained changes in baroreceptor loading status during prolonged postexercise recovery can alter the metaboreceptors' influence on heat loss. Thirteen young males performed a 1-min isometric handgrip exercise (IHG) at 60% maximal voluntary contraction followed by 2 min of forearm ischemia (to activate metaboreceptors) before and 15, 30, 45, and 60 min after a 15-min intense treadmill running exercise (>90% maximal heart rate) in the heat (35°C). This was repeated on three separate days with continuous lower body positive (LBPP, +40 mmHg), negative (LBNP, -20 mmHg), or no pressure (Control) from 13- to 65-min postexercise. Sweat rate (ventilated capsule; forearm, chest, upper back) and cutaneous vascular conductance (CVC; forearm, upper back) were measured. Relative to pre-IHG levels, sweating at all sites increased during IHG and remained elevated during ischemia at baseline and similarly at 30, 45, and 60 min postexercise (site average sweat rate increase during ischemia: Control, 0.13 ± 0.02; LBPP, 0.12 ± 0.02; LBNP, 0.15 ± 0.02 mg·min(-1)·cm(-2); all P < 0.01), but not at 15 min (all P > 0.10). LBPP and LBNP did not modulate the pattern of sweating to IHG and ischemia (all P > 0.05). At 15-min postexercise, forearm CVC was reduced from pre-IHG levels during both IHG and ischemia under LBNP only (ischemia: 3.9 ± 0.8% CVCmax; P < 0.02). Therefore, we show metaboreceptors increase postexercise sweating in the middle to late stages of recovery (30-60 min), independent of baroreceptor loading status and similarly between skin sites. In contrast, metaboreflex modulation of forearm but not upper back CVC occurs only in the early stages of recovery (15 min) and is dependent upon baroreceptor unloading. PMID:26377560

  3. 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

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

    PubMed

    Chen, Sharon; Tyan, Yu-Chang; 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

  5. 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

  6. [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

  7. Serial assessment of arterial structure and function in patients with coarctation of the aorta undergoing stenting.

    PubMed

    Jesus, Carlos A; Assef, Jorge E; Pedra, Simone R F F; Ferreira, Waldinai P; Davoglio, Tathiane A; Petisco, Ana Cláudia G P; Saleh, Mohamed H; Le Bihan, David C S; Barretto, Rodrigo B M; Pedra, Carlos A C

    2016-05-01

    Stenting for CoA has become an acceptable treatment modality in the last 20 years. However little is known about arterial changes after this procedure. To assess arterial structure and function including peripheral reactivity and stiffness and intima-media thickness (IMT) pre and post stenting for coarctation of the aorta (CoA). Twenty-one patients [median age: 15 years (8-39)] were studied at baseline, 1 day, 6 months and 1 year after stenting. Twenty-one healthy subjects (1:1 matched) were used as controls. Left ventricular (LV) mass, ejection fraction, flow-mediated dilation (FMD) and nitrate-mediated dilation (NMD) of left brachial artery, common carotid (CC) and right subclavian artery (RSCA) IMT and pulse wave velocity (PWV) were assessed by echocardiography and vascular ultrasound. CoA patients had higher LV indexed mass (p < 0.0001), impaired FMD (p < 0.0001) and NMD (p < 0.0001), increased PWV (p < 0.0001), carotid and RSCA IMT (both p < 0.0001). All procedures were successful and resulted in significant gradient reduction (p < 0.001). One year after stenting there was improvement in LV function (p = 0.034) and although there was significant reduction of LV mass (103.29 ± 24.77 vs. 74.39 ± 22.07 g/m(2), p < 0.0001) values did not normalize. There was no significant change in FMD, NMD, PWV and CC or RSCA IMT. In patients with CoA, arterial reactivity is impaired and LV mass, arterial stiffness and thickness are increased. Although stenting is successful to relieve the obstruction resulting in better LV function and mass reduction, arterial structure and function remains abnormal after 1 year of follow-up. PMID:26723574

  8. An adaptive transfer function for deriving the aortic pressure waveform from a peripheral artery pressure waveform.

    PubMed

    Swamy, Gokul; Xu, Da; Olivier, N Bari; Mukkamala, Ramakrishna

    2009-11-01

    We developed a new technique to mathematically transform a peripheral artery pressure (PAP) waveform distorted by wave reflections into the physiologically more relevant aortic pressure (AP) waveform. First, a transfer function relating PAP to AP is defined in terms of the unknown parameters of a parallel tube model of pressure and flow in the arterial tree. The parameters are then estimated from the measured PAP waveform along with a one-time measurement of the wave propagation delay time between the aorta and peripheral artery measurement site (which may be accomplished noninvasively) by exploiting preknowledge of aortic flow. Finally, the transfer function with its estimated parameters is applied to the measured waveform so as to derive the AP waveform. Thus, in contrast to the conventional generalized transfer function, the transfer function is able to adapt to the intersubject and temporal variability of the arterial tree. To demonstrate the feasibility of this adaptive transfer function technique, we performed experiments in 6 healthy dogs in which PAP and reference AP waveforms were simultaneously recorded during 12 different hemodynamic interventions. The AP waveforms derived by the technique showed agreement with the measured AP waveforms (overall total waveform, systolic pressure, and pulse pressure root mean square errors of 3.7, 4.3, and 3.4 mmHg, respectively) statistically superior to the unprocessed PAP waveforms (corresponding errors of 8.6, 17.1, and 20.3 mmHg) and the AP waveforms derived by two previously proposed transfer functions developed with a subset of the same canine data (corresponding errors of, on average, 5.0, 6.3, and 6.7 mmHg). PMID:19783780

  9. Metabotropic glutamate receptors depress vagal and aortic baroreceptor signal transmission in the NTS.

    PubMed

    Liu, Z; Chen, C Y; Bonham, A C

    1998-11-01

    We sought to determine whether metabotropic glutamate receptors contribute to frequency-dependent depression of vagal and aortic baroreceptor signal transmission in the nucleus of the solitary tract (NTS) in vivo. In alpha-chloralose-anesthetized rabbits, we determined the number of extracellular action potentials synaptically evoked by low (1 Hz)- or high-frequency vagal (3-20 Hz) or aortic depressor nerve (ADN) (6-80 Hz) stimulation and postsynaptically evoked by the ionotropic glutamate receptor agonist alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA). The metabotropic glutamate receptor agonist (2S,1'S, 2'S)-2-(carboxycyclopropyl)glycine (L-CCG-I) attenuated NTS responses monosynaptically evoked by 1-Hz vagus stimulation by 34% (n = 25; P = 0.011), while augmenting AMPA-evoked responses by 64% (n = 17; P = 0.026). The metabotropic glutamate receptor antagonist alpha-methyl-4-phosphonophenylglycine (MPPG) did not affect NTS responses to low-frequency vagal stimulation (n = 11) or AMPA (n = 10) but augmented responses to high-frequency stimulation by 50% (n = 25; P = 0.0001). MPPG also augmented NTS responses to high-frequency ADN stimulation by 35% (n = 9; P = 0.048) but did not affect responses to low-frequency stimulation (n = 9) or AMPA (n = 7). The results suggest that metabotropic glutamate receptors, presumably at presynaptic sites, contribute to frequency-dependent depression of vagal and aortic baroreceptor signal transmission in NTS. PMID:9815076

  10. 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

  11. Sox7 controls arterial specification in conjunction with hey2 and efnb2 function.

    PubMed

    Hermkens, Dorien M A; van Impel, Andreas; Urasaki, Akihiro; Bussmann, Jeroen; Duckers, Henricus J; Schulte-Merker, Stefan

    2015-05-01

    SoxF family members have been linked to arterio-venous specification events and human pathological conditions, but in contrast to Sox17 and Sox18, a detailed in vivo analysis of a Sox7 mutant model is still lacking. In this study we generated zebrafish sox7 mutants to understand the role of Sox7 during vascular development. By in vivo imaging of transgenic zebrafish lines we show that sox7 mutants display a short circulatory loop around the heart as a result of aberrant connections between the lateral dorsal aorta (LDA) and either the venous primary head sinus (PHS) or the common cardinal vein (CCV). In situ hybridization and live observations in flt4:mCitrine transgenic embryos revealed increased expression levels of flt4 in arterial endothelial cells at the exact location of the aberrant vascular connections in sox7 mutants. An identical circulatory short loop could also be observed in newly generated mutants for hey2 and efnb2. By genetically modulating levels of sox7, hey2 and efnb2 we demonstrate a genetic interaction of sox7 with hey2 and efnb2. The specific spatially confined effect of loss of Sox7 function can be rescued by overexpressing the Notch intracellular domain (NICD) in arterial cells of sox7 mutants, placing Sox7 upstream of Notch in this aspect of arterial development. Hence, sox7 levels are crucial in arterial specification in conjunction with hey2 and efnb2 function, with mutants in all three genes displaying shunt formation and an arterial block. PMID:25834021

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

    PubMed Central

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

    2016-01-01

    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

  13. Platelet Consumption by Arterial Prostheses: The Effects of Endothelialization and Pharmacologic Inhibition of Platelet Function

    PubMed Central

    Harker, Laurence A.; Slichter, Sherrill J.; Sauvage, Lester R.

    1977-01-01

    The thrombogenic mechanism of arterial grafts has been studied by determining the relative utilization of platelets, fibrinogen and plasminogen by human arterial prostheses, and by direct examination of arterial grafts in a baboon model. Forty-one survival and turnover measurements of 51Crplatelets, 131I-fibrinogen and 125I-plasminogen in ten patients with aortofemoral knitted Dacron prostheses demonstrated platelet consumption after graft placement (platelet survival 4.2 days ± 0.5 and turnover 68,000 plat/ul/day ±10,000 compared with 8.2 days ± 0.3 and 35,000 plat/ul/day ± 5,000 respectively for control subjects with stable vascular disease, p < 0.01). In vitro platelet function test results were normal. Platelet consumption was interrupted by dipyridamole or a combination of dipyridamole and acetylsalicylic acid, and platelet survival normalized spontaneously during nine months postoperatively. No significantly increased consumption of fibrinogen or plasminogen was found in these patients with arterial grafts. Placement of impervious knitted Dacron velour aortic grafts in baboons reproduced platelet consumption that progressively normalized over six weeks postoperatively. Platelet survival measurements correlated directly with endothelial cell coverage of the graft luminal surface in these animals implying that endothelialization of the graft surface was also occurring postoperatively in patients. ImagesFig. 4.Fig. 5. PMID:411428

  14. Determinants of Functional and Structural Properties of Large Arteries in Healthy Individuals

    PubMed Central

    Tolezani, Elaine Cristina; Costa-Hong, Valéria; Correia, Gustavo; Mansur, Alfredo José; Drager, Luciano Ferreira; Bortolotto, Luiz Aparecido

    2014-01-01

    Background Changes in the properties of large arteries correlate with higher cardiovascular risk. Recent guidelines have included the assessment of those properties to detect subclinical disease. Establishing reference values for the assessment methods as well as determinants of the arterial parameters and their correlations in healthy individuals is important to stratify patients. Objective To assess, in healthy adults, the distribution of the values of pulse wave velocity, diameter, intima-media thickness and relative distensibility of the carotid artery, in addition to assessing the demographic and clinical determinants of those parameters and their correlations. Methods This study evaluated 210 individuals (54% women; mean age, 44 ± 13 years) with no evidence of cardiovascular disease. The carotid-femoral pulse wave velocity was measured with a Complior® device. The functional and structural properties of the carotid artery were assessed by using radiofrequency ultrasound. Results The means of the following parameters were: pulse wave velocity, 8.7 ± 1.5 m/s; diameter, 6,707.9 ± 861.6 μm; intima-media thickness, 601 ± 131 μm; relative distensibility, 5.3 ± 2.1%. No significant difference related to sex or ethnicity was observed. On multiple linear logistic regression, the factors independently related to the vascular parameters were: pulse wave velocity, to age (p < 0.01) and triglycerides (p = 0.02); intima-media thickness, to age (p < 0.01); diameter, to creatinine (p = 0.03) and age (p = 0.02); relative distensibility, to age (p < 0.01) and systolic and diastolic blood pressures (p = 0.02 and p = 0.01, respectively). Pulse wave velocity showed a positive correlation with intima media thickness (p < 0.01) and with relative distensibility (p < 0.01), while diameter showed a positive correlation with distensibility (p = 0.03). Conclusion In healthy individuals, age was the major factor related to aortic stiffness, while age and diastolic blood pressure

  15. 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

  16. 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. PMID:23575360

  17. Effect of periodontal therapy on arterial structure and function among aboriginal australians: a randomized, controlled trial.

    PubMed

    Kapellas, Kostas; Maple-Brown, Louise J; Jamieson, Lisa M; Do, Loc G; O'Dea, Kerin; Brown, Alex; Cai, Tommy Y; Anstey, Nicholas M; Sullivan, David R; Wang, Hao; Celermajer, David S; Slade, Gary D; Skilton, Michael R

    2014-10-01

    Observational studies and nonrandomized trials support an association between periodontal disease and atherosclerotic vascular disease. Both diseases occur frequently in Aboriginal Australians. We hypothesized that nonsurgical periodontal therapy would improve measures of arterial function and structure that are subclinical indicators of atherosclerotic vascular disease. This parallel-group, randomized, open label clinical trial enrolled 273 Aboriginal Australians aged ≥18 years with periodontitis. Intervention participants received full-mouth periodontal scaling during a single visit, whereas controls received no treatment. Prespecified primary end points measured 12-month change in carotid intima-media thickness, an indicator of arterial structure, and 3- and 12-month change in pulse wave velocity, an indicator of arterial function. ANCOVA used complete case data to evaluate treatment group differences. End points could be calculated for 169 participants with follow-up data at 3 months and 168 participants at 12 months. Intima-media thickness decreased significantly after 12 months in the intervention group (mean reduction=-0.023 [95% confidence interval {CI}, -0.038 to -0.008] mm) but not in the control group (mean increase=0.002 [95% CI, -0.017 to 0.022] mm). The difference in intima-media thickness change between treatment groups was statistically significant (-0.026 [95% CI, -0.048 to -0.003] mm; P=0.03). In contrast, there were no significant differences between treatment groups in pulse wave velocity at 3 months (mean difference, 0.06 [95% CI, -0.17 to 0.29] m/s; P=0.594) or 12 months (mean difference, 0.21 [95% CI, -0.01 to 0.43] m/s; P=0.062). Periodontal therapy reduced subclinical arterial thickness but not function in Aboriginal Australians with periodontal disease, suggesting periodontal disease and atherosclerosis are significantly associated. PMID:24958498

  18. Correlation of arterial blood pressure and compliance with left ventricular structure and function in the very elderly.

    PubMed

    Rosendorff, Clive; Go, Orson; Schmeidler, James; Silverman, Jeremy M; Beeri, Michal S

    2012-01-01

    There are very few data on the relationship between systolic blood pressure (SBP), diastolic blood pressure (DBP), arterial compliance, and left ventricular structure and function, particularly left ventricular hypertrophy (LVH), in the very elderly (>75 years). SBP and arterial stiffness increase with age, and the question is: which of the two is the main stimulus to LVH? This is a cross-sectional study to compare blood pressure and arterial stiffness measures with regard to their correlations with echocardiographic parameters of LV structure and function, controlling for age and cardiovascular risk factors, in a very elderly population. Arterial stiffness was determined by radial pulse waveform using pulse contour analysis. LV dimensions were measured by transthoracic M-mode echocardiography, and diastolic function by tissue Doppler measurements of diastolic mitral annular velocities. There were 179 subjects, all male, with a mean age of 81.8 years. Using age-adjusted partial correlations, SBP, DBP, and mean arterial pressure (MAP) were correlated with parameters of LV structure and function. Correlation coefficients were: SBP versus left ventricular mass index (LVMI), r = 0.246; SBP versus early diastolic mitral annular velocity (MAV), r = -0.179; DBP versus LVMI, r = 0.199; DBP versus MAV, r = -0.199; MAP versus LVMI, r = 0.276; and MAP versus MAV, r = -0.206, all with P < .05. However, neither capacitative nor reflective arterial compliance was significantly correlated with any parameter of LV structure and function. After controlling for age and 10 cardiovascular and metabolic risk factors, the correlation between blood pressure and the measured LV parameters was substantially unchanged, as was the lack of correlation between indices of arterial compliance and the LV indices. Arterial blood pressure is correlated with LV structure and function in the very elderly, but arterial stiffness, as measured by diastolic pulse contour analysis, is not. PMID:22243840

  19. 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

  20. 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

  1. Functional assessment of the stenotic carotid artery by CFD-based pressure gradient evaluation.

    PubMed

    Liu, Xin; Zhang, Heye; Ren, Lijie; Xiong, Huahua; Gao, Zhifan; Xu, Pengcheng; Huang, Wenhua; Wu, Wanqing

    2016-09-01

    The functional assessment of a hemodynamic significant stenosis base on blood pressure variation has been applied for evaluation of the myocardial ischemic event. This functional assessment shows great potential for improving the accuracy of the classification of the severity of carotid stenosis. To explore the value of grading the stenosis using a pressure gradient (PG)-we had reconstructed patient-specific carotid geometries based on MRI images-computational fluid dynamics were performed to analyze the PG in their stenotic arteries. Doppler ultrasound image data and the corresponding MRI image data of 19 patients with carotid stenosis were collected. Based on these, 31 stenotic carotid arterial geometries were reconstructed. A combinatorial boundary condition method was implemented for steady-state computer fluid dynamics simulations. Anatomic parameters, including tortuosity (T), the angle of bifurcation, and the cross-sectional area of the remaining lumen, were collected to investigate the effect on the pressure distribution. The PG is highly correlated with the severe stenosis (r = 0.902), whereas generally, the T and the angle of the bifurcation negatively correlate to the pressure drop of the internal carotid artery stenosis. The calculation required <10 min/case, which made it prepared for the fast diagnosis of the severe stenosis. According to the results, we had proposed a potential threshold value for distinguishing severe stenosis from mild-moderate stenosis (PG = 0.88). In conclusion, the PG could serve as the additional factor for improving the accuracy of grading the severity of the stenosis. PMID:27371686

  2. Modelling arterial pressure waveforms using Gaussian functions and two-stage particle swarm optimizer.

    PubMed

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

    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

  3. 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.

  4. Clinical characteristics of functional recovery after coronary artery bypass graft surgery in Japanese octogenarians

    PubMed Central

    Tobita, Ryo; Iwata, Kentaro; Kamisaka, Kenta; Yuguchi, Satoshi; Tahara, Masayuki; Oura, Keisuke; Morisawa, Tomoyuki; Ohhashi, Satoko; Kumamaru, Megumi; Hanafusa, Yusuke; Kato, Michitaka; Saitoh, Masakazu; Sakurada, Koji; Takahashi, Tetsuya

    2016-01-01

    [Purpose] This study aimed to elucidate characteristics of postoperative physical functional recovery in octogenarians undergoing coronary artery bypass graft surgery. [Subjects and Methods] This was a multi-center, retrospective study. Nine hundred and twenty-seven elective isolated coronary artery bypass graft surgeries were evaluated (746 males and 181 females, mean age: 68.6 years, range: 31–86 years). Participants were stratified according to age < 80 years (n = 840; mean age, 67.1; range, 31–79) or > 80 years (n = 87; mean age, 82.2; range, 80–86). Patient characteristics and postoperative physical functional recovery outcomes were compared between groups. [Results] There was no significant difference between groups when considering the postoperative day at which patients could sit on the edge of the bed, stand at bedside, or walk around the bed. The postoperative day at which patients could walk 100 m independently was later in octogenarians, when compared with non-octogenarians (6.1 ± 3.2 days vs. 4.9 ± 3.9 days). In octogenarians, the percentage of patients who could walk 100 m independently within 8 days after surgery was 79.5%. [Conclusion] A postoperative target time in octogenarians for independent walking, following coronary artery bypass grafting, can be set at approximately 6 days. PMID:27065553

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

    PubMed

    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. 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

  7. 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.

  8. Exercise training improves endothelial function in resistance arteries of young prehypertensives.

    PubMed

    Beck, D T; Martin, J S; Casey, D P; Braith, R W

    2014-05-01

    Prehypertension is associated with reduced conduit artery endothelial function and perturbation of oxidant/antioxidant status. It is unknown whether endothelial dysfunction persists to resistance arteries and whether exercise training affects oxidant/antioxidant balance in young prehypertensives. We examined resistance artery function using venous occlusion plethysmography measurement of forearm (FBF) and calf blood flow (CBF) at rest and during reactive hyperaemia (RH), as well as lipid peroxidation (8-iso-PGF2α) and antioxidant capacity (Trolox-equivalent antioxidant capacity; TEAC) before and after exercise intervention or time control. Forty-three unmedicated prehypertensive and 15 matched normotensive time controls met screening requirements and participated in the study (age: 21.1±0.8 years). Prehypertensive subjects were randomly assigned to resistance exercise training (PHRT; n=15), endurance exercise training (PHET; n=13) or time-control groups (PHTC; n=15). Treatment groups exercised 3 days per week for 8 weeks. Peak and total FBF were lower in prehypertensives than normotensives (12.7±1.2 ml min(-1) per100 ml tissue and 89.1±7.7 ml min(-1) per 100 ml tissue vs 16.3±1.0 ml min(-1) per 100 ml tissue and 123.3±6.4 ml min(-1) per 100 ml tissue, respectively; P<0.05). Peak and total CBF were lower in prehypertensives than normotensives (15.3±1.2 ml min(-1) per 100 ml tissue and 74±8.3 ml min(-1) per 100 ml tissue vs 20.9±1.4 ml min(-1) per 100 ml tissue and 107±9.2 ml min(-1) per 100 ml tissue, respectively; P<0.05). PHRT and PHET improved humoral measures of TEAC (+24 and +30%) and 8-iso-PGF2α (-43 and -40%, respectively; P < or = 0.05). This study provides evidence that young prehypertensives exhibit reduced resistance artery endothelial function and that short-term (8 weeks) resistance or endurance training are effective in improving resistance artery endothelial function and oxidant

  9. EXERCISE TRAINING IMPROVES ENDOTHELIAL FUNCTION IN RESISTANCE ARTERIES OF YOUNG PREHYPERTENSIVES

    PubMed Central

    Beck, Darren T.; Martin, Jeffrey S.; Casey, Darren P.; Braith, Randy W.

    2013-01-01

    Prehypertension is associated with reduced conduit artery endothelial function and perturbation of oxidant/antioxidant status. It is unknown if endothelial dysfunction persists to resistance arteries and if exercise training effects oxidant/antioxidant balance in young prehypertensives. We examined resistance artery function using venous occlusion plethysmography measurement of forearm (FBF) and calf blood flow (CBF) at rest and during reactive hyperemia, as well as lipid peroxidation (8-iso-PGF2α) and antioxidant capacity (Trolox-equivalent antioxidant capacity; TEAC) before and after exercise intervention or time-control. Forty-three unmedicated prehypertensive and fifteen matched normotensive time-controls met screening requirements and participated in the study (age: 21.1±0.8 years). Prehypertensive subjects were randomly assigned to resistance exercise training (PHRT; n=15), endurance exercise training (PHET; n=13) or time-control groups (PHTC; n=15). Treatment groups exercised 3 days per week for 8 weeks. Peak and total FBF were lower in prehypertensives than normotensives (12.7±1.2 ml/min/100ml tissue and 89.1±7.7 ml/min/100ml tissue vs. 16.3±1.0 ml/min/100ml tissue and 123.3±6.4 ml/min/100ml tissue, respectively; p<0.05). Peak and total CBF were lower in prehypertensives than normotensives (15.3±1.2 ml/min/100ml tissue and 74±8.3 ml/min/100ml tissue vs. 20.9±1.4 ml/min/100ml tissue and 107±9.2 ml/min/100ml tissue, respectively; p<0.05). PHRT and PHET improved humoral measures of Trolox-equivalent antioxidant-capacity (TEAC) (+24% and +30%) and 8-iso-PGF2α (−43% and −40%, respectively; p<0.05). This study provides evidence that young prehypertensives exhibit reduced resistance artery endothelial function and that short term (8weeks) resistance or endurance training are effective in improving resistance artery endothelial function and oxidant/antioxidant balance in young prehypertensives. PMID:24172292

  10. Functional Development of the Coronary Collateral Circulation During Coronary Artery Occlusion in the Conscious Dog

    PubMed Central

    Bloor, Colin M.; White, Francis C.

    1972-01-01

    We studied changes in the coronary collateral circulation during coronary artery occlusion in 14 conscious dogs by: a) determining simultaneous changes in peripheral coronary pressure (PCP) and retrograde flow (RF) after abrupt coronary artery occlusion; b) correlating these functional indices with quantitative anatomic indices (AI) of coronary collateral development (Menick et al: Am Heart J 82:503-510, 1971); and c) observing changes in these indices after repeated reocclusions of a coronary artery. These dogs were subjected to left circumflex coronary artery (LCCA) occlusions for 2 hours to 8 days; pressure tubes were implanted in the aorta and LCCA, the latter tube placed distal to an occlusive cuff for PCP and RF measurements. Afterwards the animals were sacrificed, their hearts injected with a modified Schlesinger's gelatin mass, and AI determined. During 2 to 24 hour LCCA occlusions (11 dogs) mean PCP rose to levels 50 to 80% of prevailing aortic pressure. During repreated 2- to 24-hour occlusions (2 dogs) in the same dog, the rate at which PCP rose increased. Retrograde flow was unchanged during 2- to 24-hour occlusions. Anatomic indices of these dogs were in the same range as those observed in unoccluded controls. When LCCA occlusion was maintained for more than 4 days (3 dogs), mean PCP rose during the first 24 hours and then remained stable; RF did not change until 4 days into occlusion and then increased. Anatomic indices of dogs occluded for more than 4 days were significantly greater (P < 0.001) than those of the 2- to 24-hour occlusion groups. Our study shows that: a) the early PCP rise after occlusion is not associated with an increase in RF, b) RF is a better index of collateral function and c) RF correlated well with the anatomic development of the collateral bed. ImagesFig 2Fig 1 PMID:5033259

  11. 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

  12. Peripheral artery disease is associated with severe impairment of vascular function.

    PubMed

    Kiani, Soroosh; Aasen, Jonathan G; Holbrook, Monika; Khemka, Abhishek; Sharmeen, Farhana; LeLeiko, Rebecca M; Tabit, Corey E; Farber, Alik; Eberhardt, Robert T; Gokce, Noyan; Vita, Joseph A; Hamburg, Naomi M

    2013-04-01

    Patients with peripheral artery disease (PAD) have higher cardiovascular event rates than patients with established coronary artery disease (CAD) and abnormal endothelial function predicts cardiovascular risk in PAD and CAD. We investigated the hypothesis that PAD is associated with a greater degree of impairment in vascular function than CAD. We used several non-invasive tests to evaluate endothelial function in 1320 men and women with combined PAD and CAD (n = 198), PAD alone (n = 179), CAD alone (n = 466), or controls aged > 45 years without CAD or PAD (n = 477). Patients with PAD had lower brachial artery flow-mediated dilation (5.1 ± 3.9% PAD and CAD, 5.9 ± 4.4% PAD alone) compared to patients with CAD alone (7.0 ± 4.5%) and no PAD or CAD (8.1 ± 5.1%, p < 0.0001). In multivariable models adjusting for clinical covariates and the presence of CAD, PAD remained associated with lower flow-mediated dilation (p < 0.0001). PAD was associated also with lower nitroglycerin-mediated dilation and reactive hyperemia. Patients with both PAD and CAD had a lower digital pulse amplitude tonometry (PAT) ratio in unadjusted models but not in adjusted models. Flow-mediated dilation was modestly associated with PAT ratio in patients with atherosclerotic disease (r = 0.23, p < 0.0001) but not among control participants (r = 0.008, p = 0.93). Our findings indicate that patients with PAD have greater impairment of vasodilator function and are consistent with the possibility that endothelial dysfunction may contribute to adverse cardiovascular prognosis in PAD. PMID:23509089

  13. Peripheral artery disease is associated with severe impairment of vascular function

    PubMed Central

    Kiani, Soroosh; Aasen, Jonathan G; Holbrook, Monika; Khemka, Abhishek; Sharmeen, Farhana; LeLeiko, Rebecca M; Tabit, Corey E; Farber, Alik; Eberhardt, Robert T; Gokce, Noyan; Vita, Joseph A; Hamburg, Naomi M

    2013-01-01

    Patients with peripheral artery disease (PAD) have higher cardiovascular event rates than patients with established coronary artery disease (CAD) and abnormal endothelial function predicts cardiovascular risk in PAD and CAD. We investigated the hypothesis that PAD is associated with a greater degree of impairment in vascular function than CAD. We used several non-invasive tests to evaluate endothelial function in 1320 men and women with combined PAD and CAD (n = 198), PAD alone (n = 179), CAD alone (n = 466), or controls aged > 45 years without CAD or PAD (n = 477). Patients with PAD had lower brachial artery flow-mediated dilation (5.1 ± 3.9% PAD and CAD, 5.9 ± 4.4% PAD alone) compared to patients with CAD alone (7.0 ± 4.5%) and no PAD or CAD (8.1 ± 5.1%, p < 0.0001). In multivariable models adjusting for clinical covariates and the presence of CAD, PAD remained associated with lower flow-mediated dilation (p < 0.0001). PAD was associated also with lower nitroglycerin-mediated dilation and reactive hyperemia. Patients with both PAD and CAD had a lower digital pulse amplitude tonometry (PAT) ratio in unadjusted models but not in adjusted models. Flow-mediated dilation was modestly associated with PAT ratio in patients with atherosclerotic disease (r = 0.23, p < 0.0001) but not among control participants (r = 0.008, p = 0.93). Our findings indicate that patients with PAD have greater impairment of vasodilator function and are consistent with the possibility that endothelial dysfunction may contribute to adverse cardiovascular prognosis in PAD. PMID:23509089

  14. Effect of coronary artery bypass grafting on left ventricular diastolic function.

    PubMed

    Lawson, W E; Seifert, F; Anagnostopoulos, C; Hills, D J; Swinford, R D; Cohn, P F

    1988-02-01

    Because left ventricular (LV) diastolic function is abnormal in patients with coronary artery disease (CAD), pulsed Doppler echocardiography was used to evaluate LV filling before and after coronary artery bypass grafting (CABG). Filling was evaluated by Doppler in 2 studies: (1) in a group of 41 unpaired patients (11 with angiographically normal coronary arteries, 14 with CAD but without CABG and 16 at 1 week after CABG) and (2) in a group of 12 patients with CAD before and 1 week after CABG. Doppler sampling at the level of the mitral anulus was analyzed for the deceleration half-time and for the ratio of peak late (A) to peak early (E) filling velocity, measures reflecting early ventricular filling and the relative contribution of atrial contraction to ventricular filling. In the first study the deceleration half-time was significantly prolonged in both CAD and CABG groups. The late to early peak transmitral velocity ratio, however, was significantly prolonged only in the nonrevascularized CAD patients. In the second group of CAD patients studied before and 1 week after surgical revascularization, both the late to early peak transmitral velocity ratio and the deceleration half-time showed significant postoperative improvement. Thus, patients with CAD showed impairment in early LV filling and a compensatory increase in the proportion of filling with active atrial contraction. Successful CABG appears to result in normalization of early filling and decreased reliance on active atrial transport. PMID:3257633

  15. 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

  16. 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

  17. Circulating MicroRNAs Characterizing Patients with Insufficient Coronary Collateral Artery Function

    PubMed Central

    Hakimzadeh, Nazanin; Nossent, A. Yaël; van der Laan, Anja M.; Schirmer, Stephan H.; de Ronde, Maurice W. J.; Pinto-Sietsma, Sara-Joan; van Royen, Niels; Quax, Paul H. A.; Hoefer, Imo E.; Piek, Jan J.

    2015-01-01

    Background Coronary collateral arteries function as natural bypasses in the event of coronary obstruction. The degree of collateral network development significantly impacts the outcome of patients after an acute myocardial infarction (AMI). MicroRNAs (miRNAs, miRs) have arisen as biomarkers to identify heterogeneous patients, as well as new therapeutic targets in cardiovascular disease. We sought to identify miRNAs that are differentially expressed in chronic total occlusion (CTO) patients with well or poorly developed collateral arteries. Methods and Results Forty-one CTO patients undergoing coronary angiography and invasive assessment of their coronary collateralization were dichotomized based on their collateral flow index (CFI). After miRNA profiling was conducted on aortic plasma, four miRNAs were selected for validation by real-time quantitative reverse transcription polymerase chain reaction in patients with low (CFI<0.39) and high (CFI>0.39) collateral artery capacity. We confirmed significantly elevated levels of miR423-5p (p<0.05), miR10b (p<0.05), miR30d (p<0.05) and miR126 (p<0.001) in patients with insufficient collateral network development. We further demonstrated that each of these miRNAs could serve as circulating biomarkers to discriminate patients with low collateral capacity (p<0.01 for each miRNA). We also determined significantly greater expression of miR30d (p<0.05) and miR126 (p<0.001) in CTO patients relative to healthy controls. Conclusion The present study identifies differentially expressed miRNAs in patients with high versus low coronary collateral capacity. We have shown that these miRNAs can function as circulating biomarkers to discriminate between patients with insufficient or sufficient collateralization. This is the first study to identify miRNAs linked to coronary collateral vessel function in humans. PMID:26331273

  18. Effects of Recombinant Human Erythropoietin on Resistance Artery Endothelial Function in Stage 4 Chronic Kidney Disease

    PubMed Central

    Briet, Marie; Barhoumi, Tlili; Mian, Muhammad Oneeb Rehman; Sierra, Cristina; Boutouyrie, Pierre; Davidman, Michael; Bercovitch, David; Nessim, Sharon J.; Frisch, Gershon; Paradis, Pierre; Lipman, Mark L.; Schiffrin, Ernesto L.

    2013-01-01

    Background Recent studies have raised concern about the safety of erythropoiesis‐stimulating agents because of evidence of increased risk of hypertension and cardiovascular morbidity and mortality in chronic kidney disease (CKD) patients. In the present study, we investigated the effects of recombinant human erythropoietin (EPO) on endothelial function of gluteal subcutaneous resistance arteries isolated from 17 stage 4 patients (estimated glomerular filtration rate 21.9±7.4 mL/min per 1.73 m2) aged 63±13 years. Methods and Results Arteries were mounted on a pressurized myograph. EPO impaired endothelium‐dependent relaxation in a concentration‐dependent manner. The maximal response to acetylcholine with EPO at 1, 10, and 20 IU/mL was reduced by 12%, 34%, and 43%, respectively, compared with the absence of EPO (P<0.001). EPO‐induced endothelial dysfunction was significantly associated with carotid stiffness and history of cardiovascular events. EPO had no effect on norepinephrine‐induced vasoconstriction or sodium nitroprusside–induced relaxation. ABT‐627, an endothelin type A receptor antagonist, and tempol, a superoxide dismutase mimetic, partially reversed the altered endothelial function in the presence of EPO (P<0.01). Increased expression of endothelin‐1 was found in the vessel wall after incubation with EPO. Conclusions EPO alters endothelial function of resistance arteries in CKD patients via a mechanism involving in part oxidative stress and signaling through an endothelin type A receptor. EPO‐induced endothelial dysfunction could contribute to deleterious effects of EPO described in large interventional trials. PMID:23584809

  19. Intra-Arterial Administration of Multipotent Mesenchymal Stromal Cells Promotes Functional Recovery of the Brain After Traumatic Brain Injury.

    PubMed

    Silachev, D N; Plotnikov, E Yu; Babenko, V A; Danilina, T I; Zorov, L D; Pevzner, I B; Zorov, D B; Sukhikh, G T

    2015-08-01

    We compared the efficiency of delivery of multipotent mesenchymal stem cells into the brain after their intravenous and intra-arterial injection. Analysis of the therapeutic effects of cells after experimental traumatic brain injury revealed improvement of the neurological status and motor functions of the damaged hemisphere, the effect being more pronounced after intraarterial injection of cells. Intra-arterial administration was followed by rapid infiltration of the cells into the brain tissue and their number considerably surpassed that after intravenous infusion. Targeted delivery of multipotent mesenchymal stromal cells into the brain after their injection into the carotid arteries substantially potentiated their neuroprotective effects in traumatic brain injury. PMID:26388566

  20. Physiological functions of transient receptor potential channels in pulmonary arterial smooth muscle cells.

    PubMed

    Yang, Xiao-Ru; Lin, Mo-Jun; Sham, James S K

    2010-01-01

    The transient receptor potential (TRP) gene superfamily, which consists of 7 subfamilies with at least 28 mammalian homologues, is known to encode a wide variety of cation channels with diverse biophysical properties, activation mechanisms, and physiological functions. Recent studies have identified multiple TRP channel subtypes, belonging to the canonical (TRPC), melastatin-related (TRPM), and vanilloid-related (TRPV) subfamilies, in pulmonary arterial smooth muscle cells (PASMCs). They operate as specific Ca(2+) pathways responsive to stimuli, including Ca(2+) store depletion, receptor activation, reactive oxygen species, growth factors, and mechanical stress. Increasing evidence suggests that these channels play crucial roles in agonist-induced pulmonary vasoconstriction, hypoxic pulmonary vasoconstriction, smooth muscle cell proliferation, vascular remodeling, and pulmonary arterial hypertension. This chapter highlighted and discussed these putative physiological functions of TRP channels in pulmonary vasculatures. Since Ca(2+) ions regulate many cellular processes via specific Ca(2+) signals, future investigations of these novel channels will likely uncover more important regulatory mechanisms of pulmonary vascular functions in health and in disease states. PMID:20204726

  1. 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.

  2. Impact of acute caffeine ingestion on endothelial function in subjects with and without coronary artery disease.

    PubMed

    Shechter, Michael; Shalmon, Guy; Scheinowitz, Mickey; Koren-Morag, Nira; Feinberg, Micha S; Harats, Dror; Sela, Ben Ami; Sharabi, Yehonatan; Chouraqui, Pierre

    2011-05-01

    Although coffee is a widely used, pharmacologically active beverage, its impact on the cardiovascular system is controversial. To explore the effect of acute caffeine ingestion on brachial artery flow-mediated dilation (FMD) in subjects without coronary artery disease (CAD; controls) and patients with CAD, we prospectively assessed brachial artery FMD in 40 controls and 40 age- and gender-matched patients with documented stable CAD on 2 separate mornings 1 week to 2 weeks apart. After overnight fasting, discontinuation of all medications for ≥12 hours, and absence of caffeine for >48 hours, participants received capsules with caffeine 200 mg or placebo. One hour after drug ingestion, participants underwent brachial artery FMD and nitroglycerin-mediated dilation (NTG) using high-resolution ultrasound. As expected, patients with CAD were more often diabetic, hypertensive, obese, dyslipidemic, and smoked more than controls (p <0.01 for all comparisons). Aspirin, Clopidogrel, angiotensin-converting enzyme inhibitors, β blockers, and statins were significantly more common in patients with CAD than in controls (p <0.01 for all comparisons). At baseline, FMD, but not NTG, was significantly lower in patients with CAD compared to controls. Acute caffeine ingestion significantly increased FMD (patients with CAD 5.6 ± 5.0% vs 14.6 ± 5.0%, controls 8.4 ± 2.9% vs 18.6 ± 6.8%, p <0.001 for all comparisons) but not NTG (patients with CAD 13.0 ± 5.2% vs 13.8 ± 6.1%, controls 12.9 ± 3.9% vs 13.9 ± 5.8%, p = NS for all comparisons) and significantly decreased high-sensitivity C-reactive protein (patients with CAD 2.6 ± 1.4 vs 1.4 ± 1.2 mg/L, controls 3.4 ± 3.0 vs 1.2 ± 1.0 mg/L, p <0.001 for all comparisons) in the 2 groups compared to placebo. In conclusion, acute caffeine ingestion significantly improved endothelial function assessed by brachial artery FMD in subjects with and without CAD and was associated with lower plasma markers of inflammation. PMID:21349479

  3. 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

  4. 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.

  5. Transfer function for vital infrasound pressures between the carotid artery and the tympanic membrane.

    PubMed

    Furihata, Kenji; Yamashita, Masato

    2013-02-01

    While occupational injury is associated with numerous individual and work-related risk factors, including long working hours and short sleep duration, the complex mechanisms causing such injuries are not yet fully understood. The relationship between the infrasound pressures of the tympanic membrane [ear canal pressure (ECP)], detected using an earplug embedded with a low-frequency microphone, and the carotid artery [carotid artery pressure (CAP)], detected using a stethoscope fitted with the same microphone, can be quantitatively characterized using systems analysis. The transfer functions of 40 normal workers (19 to 57 years old) were characterized, involving the analysis of 446 data points. The ECP waveform exhibits a pulsatile character with a slow respiratory component, which is superimposed on a biphasic recording that is synchronous with the cardiac cycle. The respiratory ECP waveform correlates with the instantaneous heart rate. The results also revealed that various fatigue-related risk factors may affect the mean magnitudes of the measured pressures and the delay transfer functions between CAP and ECP in the study population; these factors include systolic blood pressure, salivary amylase activity, age, sleep duration, postural changes, chronic fatigue, and pulse rate. PMID:23363133

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

    PubMed

    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

  7. 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

  8. TRPV3 expression and vasodilator function in isolated uterine radial arteries from non-pregnant and pregnant rats.

    PubMed

    Murphy, Timothy V; Kanagarajah, Arjna; Toemoe, Sianne; Bertrand, Paul P; Grayson, T Hilton; Britton, Fiona C; Leader, Leo; Senadheera, Sevvandi; Sandow, Shaun L

    2016-08-01

    This study investigated the expression and function of transient receptor potential vanilloid type-3 ion channels (TRPV3) in uterine radial arteries isolated from non-pregnant and twenty-day pregnant rats. Immunohistochemistry (IHC) suggested TRPV3 is primarily localized to the smooth muscle in arteries from both non-pregnant and pregnant rats. IHC using C' targeted antibody, and qPCR of TRPV3 mRNA, suggested pregnancy increased arterial TRPV3 expression. The TRPV3 activator carvacrol caused endothelium-independent dilation of phenylephrine-constricted radial arteries, with no difference between vessels from non-pregnant and pregnant animals. Carvacrol-induced dilation was reduced by the TRPV3-blockers isopentenyl pyrophosphate and ruthenium red, but not by the TRPA1 or TRPV4 inhibitors HC-030031 or HC-067047, respectively. In radial arteries from non-pregnant rats only, inhibition of NOS and sGC, or PKG, enhanced carvacrol-mediated vasodilation. Carvacrol-induced dilation of arteries from both non-pregnant and pregnant rats was prevented by the IKCa blocker TRAM-34. TRPV3 caused an endothelium-independent, IKCa-mediated dilation of the uterine radial artery. NO-PKG-mediated modulation of TRPV3 activity is lost in pregnancy, but this did not alter the response to carvacrol. PMID:27073026

  9. Changes in functional status and functional capacity following coronary artery bypass surgery.

    PubMed

    Douki, Z Esmaeili; Vaezzadeh, N; Zakizad, M; Shahmohammadi, S; Sadeghi, R; Mohammadpour, R A

    2010-04-01

    The aim of the present study was to compare changes in health related-quality of life (H-RQOL) on physical functioning and mental health domains, changes in functional capacity before and 18 months after CABG surgery. Comprehensive data on 187 patients who underwent CABG surgery were prospectively collected, including preoperative factors and postoperative morbidity. Assessing functional status, the change in physical functioning score and change in mental health score were obtained using the physical functioning and mental health subscales out of the eight total subscales of the (SF-36) questionnaire. Also, functional capacity was estimated according to New York Heart Association (NYHA) class. The results showed 18 months after CABG surgery survival rates were (95.7%). Significant improvements in functional status were seen in physical functioning (p < 0.001), mental health (p < 0.000). However, there were no significant changes in the mean of functional status scores among patients in three age groups. Other significant improvement was found in functional capacity and NYHA class before and the 18 months after CABG. Functional status markedly and significantly improved after CABG surgery, particularly in physical functioning. However, the functional status among survivors of CABG surgery is worse than that of the general population. It seems further research is needed to identify factors explaining the change in H-RQOL to develop interventions to support patients. PMID:20836288

  10. LOWER EXTREMITY MANIFESTATIONS OF PERIPHERAL ARTERY DISEASE: THE PATHOPHYSIOLOGIC AND FUNCTIONAL IMPLICATIONS OF LEG ISCHEMIA

    PubMed Central

    McDermott, Mary McGrae

    2015-01-01

    Lower extremity peripheral artery disease (PAD) is frequently under-diagnosed, in part because of the wide variety of leg symptoms manifested by patients with PAD and in part because of the high prevalence of asymptomatic PAD. In primary care medical practices, 30% to 60% of PAD patients report no exertional leg symptoms and approximately 45–50% report exertional leg symptoms that are not consistent with classic intermittent claudication. The prevalence and extent of functional impairment and functional decline in PAD may also be underappreciated. Functional impairment and functional decline is common in PAD, even among those who are asymptomatic. Lower extremity ischemia is also associated with pathophysiologic changes in calf skeletal muscle including smaller calf muscle area, increased calf muscle fat content, impaired leg strength, and impaired metabolic function. People with severe PAD have poorer peroneal nerve conduction velocity compared to people with mild PAD or no PAD. The degree of ischemia-related pathophysiologic changes in lower extremity muscles and peripheral nerves of people with PAD are associated with the degree of functional impairment. New interventions are needed to improve functional performance and prevent mobility loss in the large number of PAD patients, including in those who are asymptomatic or who have exertional leg symptoms other than claudication. PMID:25908727

  11. Orthostatic hypotension and the Holmes-Adie syndrome. A study of two patients with afferent baroreceptor block.

    PubMed

    Johnson, R H; McLellan, D L; Love, D R

    1971-10-01

    Two patients who presented with symptoms due to orthostatic hypotension were found on examination to have the Holmes-Adie syndrome. Physiological investigation suggested that they both had an afferent block from baroreceptors in contrast to the efferent autonomic block found in most other cases of idiopathic orthostatic hypotension, including the cases of multisystem disease, now often called the Shy-Drager syndrome. PMID:5122384

  12. Increase in Ultrasonic Intensity of Blood Speckle across Moderate Coronary Artery Stenosis Is an Independent Predictor of Functional Coronary Artery Stenosis Measured by Fractional Flow Reserve: Pilot Study

    PubMed Central

    Tanno, Jun; Nakano, Shintaro; Kasai, Takatoshi; Ako, Junya; Nakamura, Sunao; Senbonmatsu, Takaaki; Nishimura, Shigeyuki

    2015-01-01

    Background and Aims The degree of coronary artery stenosis should be assessed both anatomically and functionally. We observed that the intensity of blood speckle (IBS) on intravascular ultrasound (IVUS) is low proximal to a coronary artery stenosis, and high distal to the stenosis. We defined step-up IBS as the distal minus the proximal IBS, and speculated that this new parameter could be used for the functional evaluation of stenosis on IVUS. The aims of this study were to assess the relationships between step-up IBS and factors that affect coronary blood flow, and between step-up IBS and fractional flow reserve (FFR). Methods and Results This study enrolled 36 consecutive patients with angina who had a single moderate stenosis in the left anterior descending artery. All patients were evaluated by integrated backscatter IVUS and intracoronary pressure measurements. FFR was calculated from measurements using a coronary pressure wire during hyperemia. Conventional gray-scale IVUS images were recorded, and integrated backscatter was measured in three cross-sectional slices proximal and distal to the stenosis. Step-up IBS was calculated as (mean distal integrated backscatter value) − (mean proximal integrated backscatter value). Stepwise multiple linear regression analysis showed that the heart rate (r = 0.45, P = 0.005), ejection fraction (r = −0.39, P = 0.01), and hemoglobin level (r = −0.32, P = 0.04) were independently correlated with step-up IBS, whereas proximal and distal IBS were not associated with these factors. There was a strong inverse correlation between step-up IBS and FFR (r = −0.84, P < 0.001), which remained significant on stepwise multiple linear regression analysis. Conclusions The newly defined parameter of step-up IBS is potentially useful for the functional assessment of coronary artery stenosis. PMID:25607986

  13. [Peculiarities of cardiac contractile function in patients with arterial hypertension depending on temperament and anxiety state].

    PubMed

    2011-01-01

    The aim of the work was to elucidate the relationship between temperament and personal anxiety and between left ventricular myocardium hypertrophy, contractility and diastolic function in 671 men (mean age 54 +/- 1.8 yr) with newly diagnosed grade II arterial hypertension who took no antihypertensive drugs before the study. The tone of vegetative nervous system, serum levels of cortisol, aldosterone, thyroxin, and insulin were measured. EchoCG was used to determine left ventricular myocardium mass (LVMM), LVMM index, the ratio of transmitral blood flow at the beginning and end of diastole, left ventricular ejection and shortening fractions, end-systolic and diastolic size and volume. Phlegmatic and melancholic patients differed from cholerics and sanguinics in the predominance of parasympathetic influences, elevated blood aldosterone and insulin levels in combination with higher LVMM and LVMM index but lower left ventricular systolic and diastolic function. These characteristics were especially well apparent in anxious subjects comprising a risk group for cardiac insufficiency. PMID:22420192

  14. [Structural, developmental and functional evaluation of the family of individuals with arterial hypertension].

    PubMed

    Radovanovic, Cremilde Aparecida Trindade; Cecilio, Hellen Pollyanna Mantelo; Marcon, Sonia Silva

    2013-03-01

    The objective of the study was to evaluate the structure, development and functionality of the family that suffers from arterial hypertension. This is a qualitative study, developed with two families using the Calgary Model of Family Evaluation. It proposes the use of three categories of analysis: structural developmental and functional, and the use of a genogram and an ecomap. The two families are nuclear, however one is formed by the couple and their three sons who are married and reside in different homes. The other is a single-parent family established by the mother and children. The married son resides at another house in the same backyard with wife and daughter The application of the model of family evaluation allowed knowing the aspects related to the structure, operation and development of the two families that interfere impair or favor the development of the care in their quotidian. PMID:23781723

  15. Measurement of brachial artery endothelial function using a standard blood pressure cuff.

    PubMed

    Maltz, Jonathan S; Tison, Geoffrey H; Alley, Hugh F; Budinger, Thomas F; Owens, Christopher D; Olgin, Jeffrey

    2015-11-01

    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, laboratory-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. 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 flow-mediated dilation (uFMD). 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 min 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%. This study illustrates the potential for an individual to conveniently measure his/her EFMA by using a low-cost reprogrammed home sphygmomanometer. PMID:26393958

  16. 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

  17. 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. PMID:26764055

  18. 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

  19. 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

  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. Sirtuin 3 deficiency is associated with inhibited mitochondrial function and pulmonary arterial hypertension in rodents and humans.

    PubMed

    Paulin, Roxane; Dromparis, Peter; Sutendra, Gopinath; Gurtu, Vikram; Zervopoulos, Sotirios; Bowers, Lyndsay; Haromy, Alois; Webster, Linda; Provencher, Steeve; Bonnet, Sebastien; Michelakis, Evangelos D

    2014-11-01

    Suppression of mitochondrial function promoting proliferation and apoptosis suppression has been described in the pulmonary arteries and extrapulmonary tissues in pulmonary arterial hypertension (PAH), but the cause of this metabolic remodeling is unknown. Mice lacking sirtuin 3 (SIRT3), a mitochondrial deacetylase, have increased acetylation and inhibition of many mitochondrial enzymes and complexes, suppressing mitochondrial function. Sirt3KO mice develop spontaneous PAH, exhibiting previously described molecular features of PAH pulmonary artery smooth muscle cells (PASMC). In human PAH PASMC and rats with PAH, SIRT3 is downregulated, and its normalization with adenovirus gene therapy reverses the disease phenotype. A loss-of-function SIRT3 polymorphism, linked to metabolic syndrome, is associated with PAH in an unbiased cohort of 162 patients and controls. If confirmed in large patient cohorts, these findings may facilitate biomarker and therapeutic discovery programs in PAH. PMID:25284742

  2. 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.

  3. A functional SNP in FLT1 increases risk of coronary artery disease in a Japanese population.

    PubMed

    Konta, Atsuko; Ozaki, Kouichi; Sakata, Yasuhiko; Takahashi, Atsushi; Morizono, Takashi; Suna, Shinichiro; Onouchi, Yoshihiro; Tsunoda, Tatsuhiko; Kubo, Michiaki; Komuro, Issei; Eishi, Yoshinobu; Tanaka, Toshihiro

    2016-05-01

    Coronary artery disease (CAD) including myocardial infarction is one of the leading causes of death in many countries. Similar to other common diseases, its pathogenesis is thought to result from complex interactions among multiple genetic and environmental factors. Recent large-scale genetic association analysis for CAD identified 15 new loci. We examined the reproducibility of these previous association findings with 7990 cases and 6582 controls in a Japanese population. We found a convincing association of rs9319428 in FLT1, encoding fms-related tyrosine kinase 1 (P=5.98 × 10(-8)). Fine mapping using tag single-nucleotide polymorphisms (SNPs) at FLT1 locus revealed that another SNP (rs74412485) showed more profound genetic effect for CAD (P=2.85 × 10(-12)). The SNP, located in intron 1 in FLT1, enhanced the transcriptional level of FLT1. RNA interference experiment against FLT1 showed that the suppression of FLT1 resulted in decreased expression of inflammatory adhesion molecules. Expression of FLT1 was observed in endothelial cells of human coronary artery. Our results indicate that the genetically coded increased expression of FLT1 by a functional SNP implicates activation in an inflammatory cascade that might eventually lead to CAD. PMID:26791355

  4. Validating a local Arterial Input Function method for improved perfusion quantification in stroke

    PubMed Central

    Willats, Lisa; Christensen, Soren; K Ma, Henry; A Donnan, Geoffrey; Connelly, Alan; Calamante, Fernando

    2011-01-01

    In bolus-tracking perfusion magnetic resonance imaging (MRI), temporal dispersion of the contrast bolus due to stenosis or collateral supply presents a significant problem for accurate perfusion quantification in stroke. One means to reduce the associated perfusion errors is to deconvolve the bolus concentration time-course data with local Arterial Input Functions (AIFs) measured close to the capillary bed and downstream of the arterial abnormalities causing dispersion. Because the MRI voxel resolution precludes direct local AIF measurements, they must be extrapolated from the surrounding data. To date, there have been no published studies directly validating these local AIFs. We assess the effectiveness of local AIFs in reducing dispersion-induced perfusion error by measuring the residual dispersion remaining in the local AIF deconvolved perfusion maps. Two approaches to locating the local AIF voxels are assessed and compared with a global AIF deconvolution across 19 bolus-tracking data sets from patients with stroke. The local AIF methods reduced dispersion in the majority of data sets, suggesting more accurate perfusion quantification. Importantly, the validation inherently identifies potential areas for perfusion underestimation. This is valuable information for the identification of at-risk tissue and management of stroke patients. PMID:21629260

  5. Thrombospondin-4 knockout in hypertension protects small-artery endothelial function but induces aortic aneurysms.

    PubMed

    Palao, Teresa; Rippe, Catarina; van Veen, Henk; VanBavel, Ed; Swärd, Karl; Bakker, Erik N T P

    2016-06-01

    Thrombospondin-4 (TSP-4) is a multidomain calcium-binding protein that has both intracellular and extracellular functions. As an extracellular matrix protein, it is involved in remodeling processes. Previous work showed that, in the cardiovascular system, TSP-4 expression is induced in the heart in response to experimental pressure overload and infarction injury. Intracellularly, it mediates the endoplasmic reticulum stress response in the heart. In this study, we explored the role of TSP-4 in hypertension. For this purpose, wild-type and TSP-4 knockout (Thbs4(-/-)) mice were treated with angiotensin II (ANG II). Hearts from ANG II-treated Thbs4(-/-) mice showed an exaggerated hypertrophic response. Interestingly, aortas from Thbs4(-/-) mice treated with ANG II showed a high incidence of aneurysms. In resistance arteries, ANG II-treated wild-type mice showed impaired endothelial-dependent relaxation. This was not observed in ANG II-treated Thbs4(-/-) mice or in untreated controls. No differences were found in the passive pressure-diameter curves or stress-strain relationships, although ANG II-treated Thbs4(-/-) mice showed a tendency to be less stiff, associated with thicker diameters of the collagen fibers as revealed by electron microscopy. We conclude that TSP-4 plays a role in hypertension, affecting cardiac hypertrophy, aortic aneurysm formation, as well as endothelial-dependent relaxation in resistance arteries. PMID:26968543

  6. Collateral vessel number, plaque burden, and functional decline in peripheral artery disease

    PubMed Central

    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

    2015-01-01

    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. PMID:25047855

  7. 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. PMID:26681305

  8. Carotid baroreceptor stimulation prevents arrhythmias induced by acute myocardial infarction through autonomic modulation.

    PubMed

    Liao, Kai; Yu, Lilei; He, Bo; Huang, Bing; Yang, Kang; Saren, Gaowa; Wang, Songyun; Zhou, Xiaoya; Jiang, Hong

    2014-11-01

    : Electrical carotid baroreceptor stimulation (CBS) has shown therapeutic potential for resistant hypertension and heart failure by resetting autonomic nervous system, but the impacts on arrhythmias remains unclear. This study evaluated the effects of CBS on ventricular electrophysiological properties in normal dog heart and arrhythmias after acute myocardial infarction (AMI). In the acute protocol, anesthetized open chest dogs were exposed to 1 hour left anterior descending coronary occlusion as AMI model. Dogs were received either sham treatment (Control group, n = 8) or CBS (CBS group, n = 8), started 1 hour before AMI. CBS resulted in pronounced prolongation of ventricular effective refractory period and reduction of the maximum action potential duration restitution slope (from 0.85 ± 0.15 in the baseline state to 0.67 ± 0.09 at the end of 1 hour, P < 0.05) before AMI. Number of premature ventricular contractions (277 ± 168 in the Control group vs. 103 ± 84 in the CBS group, P < 0.05) and episodes of ventricular tachycardia/ventricular fibrillation (7 ± 3 in the Control group vs. 3 ± 2 in the CBS group, P < 0.05) was decreased compared with the control group during AMI. CBS buffered low-frequency/high-frequency ratio raise during AMI. Ischemic size was not affected by CBS. CBS may have a beneficial impact on ventricular arrhythmias induced by AMI through modulation of autonomic tone. PMID:24979392

  9. Material coefficients of the strain energy function of pulmonary arteries in normal and cigarette smoke-exposed rats.

    PubMed

    Liu, S Q; Fung, Y C

    1993-11-01

    The effect of cigarette smoke on the stress-strain relationship of pulmonary arteries was studied in 2- and 3-month smoke-exposed rats. The animals were exposed to cigarette smoke in a smoke-generating system 10 times daily with one cigarette each time. The smoke density and the puffing duration and frequency of the system were regulated in accordance with reference values measured from human smokers. The mechanical properties of the pulmonary arteries about 450 microns in external diameter (at zero pressure) were determined in vitro by inflation and deflation tests. The average stress and middle-wall strain of the selected pulmonary arteries were determined on the basis of experimental data including inflation and deflation pressures during loading and unloading processes, respectively, and vessel diameter and length at various pressure levels, and vessel circumferential and longitudinal lengths at zero-stress state. A constitutive equation for the pulmonary arteries was derived from an energy function depending on circumferential and longitudinal Green's strains. The coefficients of the strain energy function of the pulmonary arteries were determined in both the smoke-exposed and control rats by fitting the experimental stress-strain data with the constitutive equation. It was found that the wall stress of the pulmonary arteries at a given strain and most of the coefficients of the strain energy function were increased in both the 2- and 3-month smoke-exposed rats in comparison with those in the corresponding controls. These results indicated that cigarette smoke induced an increase in the wall stiffness of the pulmonary arteries in the rats. PMID:8262988

  10. 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

  11. Selective down-regulation of KV2.1 function contributes to enhanced arterial tone during diabetes.

    PubMed

    Nieves-Cintrón, Madeline; Nystoriak, Matthew A; Prada, Maria Paz; Johnson, Kenneth; Fayer, William; Dell'Acqua, Mark L; Scott, John D; Navedo, Manuel F

    2015-03-20

    Enhanced arterial tone is a leading cause of vascular complications during diabetes. Voltage-gated K(+) (KV) channels are key regulators of vascular smooth muscle cells (VSMCs) contractility and arterial tone. Whether impaired KV channel function contributes to enhance arterial tone during diabetes is unclear. Here, we demonstrate a reduction in KV-mediated currents (IKv) in VSMCs from a high fat diet (HFD) mouse model of type 2 diabetes. In particular, IKv sensitive to stromatoxin (ScTx), a potent KV2 blocker, were selectively reduced in diabetic VSMCs. This was associated with decreased KV2-mediated regulation of arterial tone and suppression of the KV2.1 subunit mRNA and protein in VSMCs/arteries isolated from HFD mice. We identified protein kinase A anchoring protein 150 (AKAP150), via targeting of the phosphatase calcineurin (CaN), and the transcription factor nuclear factor of activated T-cells c3 (NFATc3) as required determinants of KV2.1 suppression during diabetes. Interestingly, substantial reduction in transcript levels for KV2.1 preceded down-regulation of large conductance Ca(2+)-activated K(+) (BKCa) channel β1 subunits, which are ultimately suppressed in chronic hyperglycemia to a similar extent. Together, our study supports the concept that transcriptional suppression of KV2.1 by activation of the AKAP150-CaN/NFATc3 signaling axis contributes to enhanced arterial tone during diabetes. PMID:25670860

  12. Endothelial function, arterial stiffness and adherence to the 2010 Dietary Guidelines for Americans: a cross-sectional analysis.

    PubMed

    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

    2015-06-14

    Endothelial dysfunction and arterial stiffness are early predictors of CVD. Intervention studies have suggested that diet is related to vascular health, but most prior studies have tested individual foods or nutrients and relied on small samples of younger adults. The purpose of the present study was to examine the relationships 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 Adherence Index (DGAI-2010). Endothelial function was assessed via brachial artery ultrasound and arterial stiffness via arterial tonometry. In age-, sex- and cohort-adjusted analyses, a higher DGAI-2010 score (greater adherence) was modestly associated with a lower resting flow velocity, hyperaemic response, mean arterial pressure, carotid-femoral pulse wave velocity (PWV), and augmentation index, but not associated with resting arterial diameter or flow-mediated dilation (FMD). In multivariable models adjusting for cardiovascular risk factors, only the association of a higher DGAI-2010 score with a lower baseline flow velocity 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 relationship of higher DGAI-2010 scores with lower mean arterial pressure, PWV 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 a lower peripheral blood flow velocity and arterial wave reflection, but not FMD. The present results suggest a link between adherence to the Dietary Guidelines and favourable vascular health. PMID:25885520

  13. 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

  14. [Functional assessment of the hepatic arterial blood flow by pharmacoradiography (author's transl)].

    PubMed

    Stellamor, K; Hruby, W; Peschl, L

    1981-12-01

    By means of celiacography it was possible to demonstrate that parenteral medication with parathormone creates a selective dilatation of the liver vessels in man, provided that they are dilatable. This hemodynamic hormone effect could not be traced in the other mesenteric vessels. The increase of portal hypertension resulting from cirrhosis leads to a loss of the dilating ability of liver vessels. This regressive reaction is well demonstrated on the parathormon-celiaco-gram. Thus a functional assessment of the hepatic blood flow is possible. The extent of the dilatability of the liver artery seems to be of great importance for the prognosis and indication of the porto-systemic shunt-operation. Moreover we could show that an increase in the liver perfusion demonstrates pathologic liver processes in a better way. PMID:7323629

  15. 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

  16. Arterial input function and gray matter cerebral blood volume measurements in children

    PubMed Central

    Withey, Stephanie B.; Novak, Jan; MacPherson, Lesley

    2015-01-01

    Purpose To investigate how arterial input functions (AIFs) vary with age in children and compare the use of individual and population AIFs for calculating gray matter CBV values. Quantitative measures of cerebral blood volume (CBV) using dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) require measurement of an AIF. AIFs are affected by numerous factors including patient age. Few data presenting AIFs in the pediatric population exists. Materials and Methods Twenty‐two previously treated pediatric brain tumor patients (mean age, 6.3 years; range, 2.0–15.3 years) underwent DSC‐MRI scans on a 3T MRI scanner over 36 visits. AIFs were measured in the middle cerebral artery. A functional form of an adult population AIF was fitted to each AIF to obtain parameters reflecting AIF shape. The relationship between parameters and age was assessed. Correlations between gray matter CBV values calculated using the resulting population and individual patient AIFs were explored. Results There was a large variation in individual patient AIFs but correlations between AIF shape and age were observed. The center (r = 0.596, P < 0.001) and width of the first‐pass peak (r = 0.441, P = 0.007) were found to correlate significantly with age. Intrapatient coefficients of variation were significantly lower than interpatient values for all parameters (P < 0.001). Differences in CBV values calculated with an overall population and age‐specific population AIF compared to those calculated with individual AIFs were 31.3% and 31.0%, respectively. Conclusion Parameters describing AIF shape correlate with patient age in line with expected changes in cardiac output. In pediatric DSC‐MRI studies individual patient AIFs are recommended. J. Magn. Reson. Imaging 2016;43:981–989 PMID:26514288

  17. Cardiovascular and neurohumoral postural responses and baroreceptor abnormalities during a course of adjunctive vasodilator therapy with felodipine for congestive heart failure.

    PubMed

    Kassis, E; Amtorp, O

    1987-06-01

    Studies in patients with congestive heart failure (CHF) have demonstrated an abnormal beta-adrenergic reflex vasodilation during orthostatic tilt. Baroreflex modulation of vascular resistance in patients with CHF was investigated during therapy with a vasoselective calcium antagonist, felodipine. Eight patients on conventional therapy for severe CHF were studied after a 3 week course of additional felodipine or placebo treatment under randomized, double-blind, and crossover conditions. Forearm subcutaneous vascular resistance (FSVR) was estimated with use of the local 133Xe washout. Aortic pulsatile stretch, expressed as the systolic distension in percent of diastolic diameter, was calculated from echocardiographic measurements of aortic root diameters. At 3 weeks, felodipine reduced the arterial pressure, systemic vascular resistance, and FSVR, preserved cardiac filling pressures and heart rate, and increased cardiac output, stroke volume, and aortic pulsatile stretch. Upright tilt (45 degrees) was used to study baroreflex-mediated cardiovascular responses. The unloading of cardiopulmonary baroreceptors during upright tilt was substantial and about equal during both treatment courses, but the pulse pressure was maintained during the placebo and decreased during the felodipine period. During tilt, the patients on placebo failed to increase heart rate and their FSVR, systemic vascular resistance, and arterial mean pressure were decreased, whereas during tilt after felodipine, heart rate and systemic vascular resistance increased to maintain arterial mean pressure and FSVR also tended to increase. Both the stroke volume and aortic pulsatile stretch increased during tilt in patients on placebo but they decreased in those on felodipine. The tilt caused increments in circulating norepinephrine and epinephrine levels during both treatment regimens. Regulation of FSVR during the sympathetic stimulation of orthostatic stress was further elucidated. Proximal neural blockade

  18. 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

  19. The influence of coronary angioplasty of the infarct-dependent artery on systolic and diastolic function of the left ventricle.

    PubMed

    Khalilov, Sh D; Guluzade, V U; Alieva, Kh A; Mirzakhanova, L R; Imanov, G G

    2009-01-01

    The target of research is to compare the changes of systolic and diastolic functions of the left ventricle in patients with at least one month infarction after infarct-dependent artery recanalization through elective stenting. The group of 60 patients was selected, 47 men and 13 women, who underwent hospitalization in Central Hospital of Oilworkers in 2006-2007. The investigation was conducted on 30 patients (24 men and 6 women), who underwent elective stenting of LAD. The control group was composed of 30 patients (23 men and 7 women) after anterior myocardial infarction without further stenting of infarct-dependent artery. The clinical diagnosis was confirmed by coronary ventriculography. The patients underwent the echocardiography the day before stenting. The "Sonoline G60 (Siemens, Germany)" machine with 2.5MHz probe has been used. The echocardiography was repeated after 7 days and 3, 6, 12 months after stent implantation. The standard parameters of systolic and diastolic function of the left ventricle were identified during investigation. The statistical processing was delivered through PC with Excel program set. All data are presented in (M+/-m), where the M--mean value, m--standard mean fault. Comparison of the data was conducted with Student criterion. The results of treatment of patients with and without further stenting of infarct-dependent artery were compared. It was found that the stenting of infarct-dependent artery with standard therapy in patients after myocardial infarction has better impact on systolic function, than traditional medical therapy without further reperfusion. The stenting of infarct-dependent artery facilitates earlier improvement of the systolic and diastolic function of the left ventricle. The diastolic relaxation grade of the left ventricle after stenting of the left coronary artery is higher, than in patients without further revascularization. PMID:19644191

  20. Perinatal Taurine Alters Arterial Pressure Control and Renal Function in Adult Offspring

    PubMed Central

    Roysommuti, Sanya; Lerdweeraphon, Wichaporn; Malila, Pisamai; Jirakulsomchok, Dusit; Wyss, J. Michael

    2009-01-01

    The present study investigates the effect of perinatal taurine exposure on renal function in adult, female rats on a high sugar diet. Perinatal taurine depleted (TD), supplemented (TS) or untreated control (C) female offspring were fed normal rat chow and tap water (CW,TDW or TSW) or tap water with 5% glucose (CG, TDG or TSG) after weaning. At 7–8 weeks of age, renal function was studied in the conscious, restrained rats. Mean arterial pressure was significantly higher in TDW, TDG, and TSG rats. Plasma sodium concentration was significantly lower in all glucose treated animals, but the greatest decrease was in TDW rats. Basal renal blood flow was lowest in TSW and TSG, and the responses to a saline load were also lowest in those two groups. These changes were consistent with increased renal vascular resistance. The basal glomerular filtration rate was lowest in TSW, but the responses to a saline load were similar in all of the groups. Water excretion was lower in TSG and TSW, consistent with increased renal tubular water reabsorption. These data suggest that perinatal taurine exposure alters normal renal function and renal responses to dietary sugar in adult female offspring. PMID:19239145

  1. [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). PMID:24908958

  2. 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.

  3. Functional Class and Targeted Therapy Are Related to the Survival in Patients with Pulmonary Arterial Hypertension

    PubMed Central

    Park, Yae Min; Choi, Deok Young; Baek, Han Joo; Jung, Sung Hwan; Choi, In Suck; Shin, Eak Kyun

    2014-01-01

    Purpose Pulmonary arterial hypertension (PAH) is an orphan disease showing poor prognosis. The purpose of study was to evaluate clinical factors influencing outcomes in PAH. Materials and Methods Patients who were diagnosed with PAH at a single center were reviewed retrospectively. Forty patients (34.9±14.5 years, 80% of female) were enrolled. Results Causes were congenital heart disease in 24 (60%), connective tissue disease in 8 (20%) and idiopathic PAH in 6 (15%). Sixteen patients (40%) were WHO functional class III or IV at the time of diagnosis. Twenty seven patients (67.5%) received molecular targeted therapy. During follow-up (53.6±45.5 months), 10 patients (25%) died and 1-, 2-, and 8 year survival rates were 91.3%, 78.7%, and 66.8%, respectively. As expected, median survival of patients with functional class I or II were significantly longer than patients with III or IV (p=0.041). Interestingly, patients with molecular targeted therapy showed longer survival than conventional therapy (p=0.021). Conclusion WHO functional class at the time of diagnosis was the strong predictor of survival, and molecular targeted therapy could significantly improve the survival. Therefore, early screening and intensive management would be crucial to improve the prognosis in the patient with PAH. PMID:25323888

  4. Parameters of arterial function and structure in adult patients after coarctation repair.

    PubMed

    Trojnarska, Olga; Mizia-Stec, Katarzyna; Gabriel, Marcin; Szczepaniak-Chicheł, Ludwina; Katarzyńska-Szymańska, Agnieszka; Grajek, Stefan; Tykarski, Andrzej; Gąsior, Zbigniew; Kramer, Lucyna

    2011-07-01

    Regardless of a successful operation, patients with coarctation of aorta (CoAo) are exposed to the risk of hypertension and a propensity to vascular and end-organ damage. The aim of this study is to evaluate the influence of residual aorta stenosis as well as the age at the operation on the parameters of arterial function and structure in patients after CoAo repair. Eighty-five patients after CoAo repair (53 males; mean age: 34.6 ± 10.3 years, mean age at the repair: 10.9 ± 8.2 years) were enrolled in the study. The control group consisted of 30 healthy subjects (18 males; mean age: 33.6 ± 8.2 years). Indices of systemic arterial remodeling [flow-mediated dilatation (FMD), nitroglycerine-mediated vasodilatation (NMD), carotid intima-media thickness (IMT), pulse wave velocity (PWV)] were analyzed in all study patients. In normotensive patients after CoAo repair (47/55%), a significantly increased PWV was observed in comparison to the control group (6.8 ± 1.2 vs. 5.4 ± 0.9 m/s; p = 0.003), with no difference in IMT values (0.53 ± 0.1 vs. 0.51 ± 0.1 mm; p = 0.06). Mean FMD (4.8 ± 2.8 vs. 8.5 ± 2.3%; p = 0.00003) and NMD (11.3 ± 4.6 vs. 19.8 ± 7.2%; p = 0.00001) were lower than in the controls. In patients with a residual aorta stenosis (46/54%), defined as an arm-leg pressure gradient ≥ 20 mmHg, no differences were found within the scope of both systolic and diastolic blood pressure and of all of the examined vascular parameters. No significant correlations were revealed between the vascular parameters and the gradient across descending aorta as well as the age at the operation. Residual stenosis in the descending aorta does not affect the arterial vasodilatation nor stiffness in patients after CoAo repair. An early surgery does not influence the remodeling of the vessels, which supports the thesis that CoAo is a generalized vascular disease and that even an early operation cannot prevent the progressive and vascular changes and end-organ damage. PMID

  5. 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.

  6. 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. PMID:26119481

  7. 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

  8. Short-term exercise training improves vascular function in hypercholesterolemic rabbit femoral artery.

    PubMed

    Jen, Chauying J; Liu, Yu-Fan; Chen, Hsiun-Ing

    2005-06-30

    Chronic exercise in healthy or hypercholesteremic animals for at least two months improves their vascular functions. This study is to examine whether short-term exercise training protocols can correct early-stage vascular dysfunction induced by high-cholesterol diet feeding. Male New Zealand White rabbits were fed for 2, 4 or 6 weeks with rabbit chow with or without the addition of 2% (w/w) cholesterol. They were further divided into control and exercise groups. Animals in exercise groups ran on a leveled treadmill for the same time periods as diet intervention. At the end of experiments, femoral arteries were dissected, loaded with fura 2-AM, and mounted in a tissue flow chamber. Phenylephrine-precontracted vessel specimens were exposed to acetylcholine. The endothelial intracellular calcium elevation and vasorelaxation were determined simultaneously under an epifluorescence microscope with ratio imaging capability. En face oil red O staining was used to evaluate fatty streak formation. Our results showed that 1) high-cholesterol diet feeding for > or = 4 weeks caused lipid deposition, reduced the acetylcholine-evoked endothelial calcium signaling, and impaired both endothelium-dependent and endothelium-independent vascular responses in a time-dependent manner; 2) vasorelaxation at given levels of endothelial intracellular calcium elevation decreased in hypercholesterolemia; 3) concomitant exercise program had reverse effects. We conclude that high-cholesterol diet intervention for as short as 4 weeks induces vascular structural changes, impairs endothelial intracellular calcium signaling and vasodilatation in rabbit femoral arteries. Short-term exercise training in parallel completely eliminates these adverse effects so long as the diet intervention is no more than 6 weeks. PMID:16201452

  9. 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

  10. 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. PMID:20421515

  11. 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. PMID:26104291

  12. 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

  13. Arterial Structure and Function in Ambulatory Adolescents with Cerebral Palsy Are Not Different from Healthy Controls

    PubMed Central

    Martin, Audra A.; Cotie, Lisa M.; Timmons, Brian W.; Gorter, Jan Willem; MacDonald, Maureen J.

    2012-01-01

    Physical inactivity in youth with cerebral palsy (CP) places them at increased risk of developing cardiovascular disease. The current study assessed indices of arterial health in adolescents with CP, classified as levels I-II of the Gross Motor Function Classification System (GMFCS) (n = 11, age 13.2 ± 2.1 yr), in comparison to age- and sex-matched controls (n = 11, age 12.4 ± 2.3 yr). Groups were similar in anthropometric measurements, resting blood pressures, and heart rates. There were no group differences in brachial flow-mediated dilation (11.1 ± 7.8 versus 6.1 ± 3.6), carotid intima-media thickness (0.42 ± 0.04 versus 0.41 ± 0.03 mm), and distensibility (0.008 ± 0.002 versus 0.008 ± 0.002 mmHg) or central (4.3 ± 0.6 versus 4.1 ± 0.9 m/s) and peripheral pulse wave velocity (7.1 ± 1.7 versus 7.6 ± 1.1 m/s); CP versus healthy controls, respectively. Vigorous intensity physical activity (PA) was lower in the CP group (CP: 38 ± 80 min versus controls: 196 ± 174 min); groups were similar in light and moderate intensity PA levels. Arterial health of ambulatory youth with CP is not different from a control group despite lower vigorous PA levels. Similar studies need to examine individuals with more pronounced mobility limitations (GMFCS level III–V). PMID:22778755

  14. 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

  15. Increased plasma neopterin levels are associated with reduced endothelial function and arterial elasticity in hypertension.

    PubMed

    Zhang, Y-Y; Tong, X-Z; Xia, W-H; Xie, W-L; Yu, B-B; Zhang, B; Chen, L; Tao, J

    2016-07-01

    Inflammation has been shown to play a pivotal role in the pathogenesis and development of hypertensive vascular injury. Neopterin is a novel marker of immune activation produced mainly by activated macrophages. Few data are available to show the association between neopterin and vascular function in hypertension. The present study was designed to investigate the relationship between neopterin levels related to arterial stiffness and endothelial function in patients with hypertension, and their changes after blood pressure-lowering treatment. Twenty-four hypertensive patients and 30 age- and gender-matched healthy volunteers were recruited. Plasma neopterin levels were higher in hypertensive patients compared with their counterparts (log-neopterin: 0.77±0.18 versus 0.61±0.16, P=0.003). Increased neopterin levels were correlated with increased brachial-ankle pulse wave velocity (baPWV; control: r=0.659, P<0.001; hypertension: r=0.487, P=0.021), and inversely associated with impaired brachial flow-mediated dilation (FMD; control: r=-0.735, P<0.001; hypertension: r=-0.557, P=0.005). Fifteen hypertensives received 3 months of standard antihypertensive treatment. Three months later, their plasma neopterin levels decreased (log-neopterin: 0.63±0.17 versus 0.50±0.19, P=0.001), whereas arterial elasticity (baPWV: 1764±101 versus 1685±96 cm s(-1), P=0.272) and endothelial function (FMD: 5.92±1.43% versus 7.73±1.31%, P<0.05) were improved. The decline in neopterin levels was linearly correlated with baPWV decrease (r=0.800, P<0.001), FMD improvement (r=0.670, P=0.006) and blood pressure reduction (r=0.548, P=0.042). Our present study demonstrated for the first time that neopterin is closely correlated with vascular dysfunctions, and measurement of plasma neopterin levels might be used as a surrogate biomarker for the clinical evaluation of vascular damage and risk stratification of future atherosclerotic cardiovascular disease in patients with hypertension. PMID

  16. Analysis of the Baroreceptor and Vestibular Receptor Inputs in the Rostral Ventrolateral Medulla following Hypotension in Conscious Rats.

    PubMed

    Lan, Yan; Lu, Huan-Jun; Jiang, Xian; Li, Li-Wei; Yang, Yan-Zhao; Jin, Guang-Shi; Park, Joo Young; Kim, Min Sun; Park, Byung Rim; Jin, Yuan-Zhe

    2015-03-01

    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

  17. The Genetic Basis for Altered Blood Vessel Function in Disease: Large Artery Stiffening

    PubMed Central

    Agrotis, Alex

    2005-01-01

    The progressive stiffening of the large arteries in humans that occurs during aging constitutes a potential risk factor for increased cardiovascular morbidity and mortality, and is accompanied by an elevation in systolic blood pressure and pulse pressure. While the underlying basis for these changes remains to be fully elucidated, factors that are able to influence the structure and composition of the extracellular matrix and the way it interacts with arterial smooth muscle cells could profoundly affect the properties of the large arteries. Thus, while age and sex represent important factors contributing to large artery stiffening, the variation in growth-stimulating factors and those that modulate extracellular production and homeostasis are also being increasingly recognized to play a key role in the process. Therefore, elucidating the contribution that genetic variation makes to large artery stiffening could ultimately provide the basis for clinical strategies designed to regulate the process for therapeutic benefit. PMID:17315605

  18. 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.

  19. 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

  20. Effect of Percutaneous Coronary Intervention on Left Ventricular Diastolic Function in Patients With Coronary Artery Disease

    PubMed Central

    Salehi, Nahid; Saidi, Mohammadreza; Rai, Alireza; Najafi, Farid; Javeedannejad, Seedmokhtar; Babanejad, Mehran; Tadbiri, Hooman

    2016-01-01

    Background: There is considerable disagreement over the effects of percutaneous coronary intervention (PCI) on left ventricular diastolic function that has necessitated the investigation of diastolic indices. The present study was conducted to evaluate left ventricular diastolic function and its indices, three months after performing the PCI procedure in patients with coronary artery disease (CAD). Methods: In a quasi-experimental clinical trial study (before and after), 51 patients with CAD scheduled for elective PCI were investigated provided that their Ejection Fraction (EF) was > 30%. Before and three months after PCI, echocardiography was carried out to evaluate left ventricular diastolic indices including the E/Ea as the most important criteria for diagnosis of diastolic heart failure (DHF). Results: Based on the E/Ea indices and after PCI, the number of patients with DHF decreased significantly: 40 patients (78.4%) before PCI versus 28 patients (54.9%) after PCI (p<0.05). The Mean and Standard error of deceleration time (DT), isovolumic relaxation time (IVRT), early diastolic mitral annulus velocity; Ea (E’), E/Ea and left ventricular ejection function (LVEF) indices underwent significant changes. In addition, MVA dur/PVA dur, PVs/PVd, and E/Ea indices had changed significantly after PCI in both genders. However, no significant difference was reported for the other indices. Conclusion: The E/Ea ratio as an important criterion for diagnosis of DHF was improved after PCI. Improvement of several other diastolic indices was observed after the PCI procedure. It can be concluded that PCI can be an effective treatment modality in patients with left ventricular diastolic indices. PMID:26234973

  1. Left ventricular diastolic function in young adults: the Coronary Artery Risk Development in Young Adults Study.

    PubMed

    Xie, X; Gidding, S S; Gardin, J M; Bild, D E; Wong, N D; Liu, K

    1995-01-01

    Doppler transmitral flow velocities have been used to assess left ventricular diastolic function. Associations of transmitral velocities with specific physiologic variables and cardiovascular risk factors have not been reported previously in a large population-based study of young adults. We performed Doppler analysis of left ventricular inflow in 3492 black and white men and women (aged 23 to 35 years) in the year-5 examination of the Coronary Artery Risk Development in Young Adults (CARDIA) Study. First third filling fraction, peak flow velocity in early diastole (PFVE), peak flow velocity in late diastole (PFVA), and the PFVA/PFVE ratio were measured. Women had higher PFVE and PFVA than had men (PFVE: 0.81 +/- 0.13 m/sec versus 0.76 +/- 0.13 m/sec; PFVA: 0.47 +/- 0.11 m/sec versus 0.43 +/- 0.10 m/sec; both p < 0.001). Gender-specific multiple regression analyses showed that age, heart rate, systolic blood pressure, left ventricular percent fractional shortening, and body weight were independently and positively related to PFVA (all p < 0.001) in men and women. Age, heart rate, and forced expiratory lung capacity in 1 second were inversely related to PFVE and first third filling fraction (both p < 0.01). Left ventricular percent fractional shortening was positively related to PFVE and first third filling fraction (p < 0.001). Age, heart rate, and body weight were positively correlated with the PFVA/PFVE ratio (all p < 0.001). Height had weak negative associations with PFVA and PFVE in women only. These results suggest that, in young adults, Doppler measures of left ventricular diastolic filling are related to age, sex, body weight, blood pressure, heart rate, left ventricular systolic function, and lung function. PMID:8611277

  2. Assessment of left ventricular function in coronary artery disease with the nuclear probe during intervention studies.

    PubMed Central

    Lahiri, A; Bowles, M J; Jones, R I; Crawley, J C; Raftery, E B

    1984-01-01

    The nuclear probe was used for measuring left ventricular function in 11 normal subjects and the results compared with those using a digital gammacamera. The probe was then used to measure left ventricular function in patients with coronary artery disease during dynamic exercise and stress atrial pacing. The ability of the probe to detect changes induced by glyceryl trinitrate was also evaluated in separate parallel studies. In the 11 normal subjects there was a good correlation between the left ventricular ejection fraction measured by the gammacamera and the nuclear probe both at rest and during exercise. Exercise increased this value by at least 5% in all normal subjects during measurements with both the gammacamera and the nuclear probe. The mean (SD) difference was -0.3% (2.60) at rest and 2.3% (5.02) at peak exercise. Both exercise and pacing produced angina in the patient group and the mean (SEM) value fell from 52% (3.5) to 28% (2.6) and from 46% (5.1) to 34% (3.2) respectively. Glyceryl trinitrate prolonged the exercise and pacing times, and the corresponding falls in ejection fraction were significantly reduced. The non-imaging nuclear probe is a cheap and portable instrument capable of assessing left ventricular function in patients with cardiac disease. It is designed for high count rate acquisition over a short period of time and can thus provide both beat to beat and summated left ventricular time activity curves suitable for quantitative analysis. It therefore has important advantages in the clinical setting and during controlled interventions compared with the gammacameras. PMID:6433946

  3. Variability of residual platelet function despite clopidogrel treatment in patients with peripheral arterial occlusive disease.

    PubMed

    Linnemann, Birgit; Schwonberg, Jan; Toennes, Stefan W; Mani, Helen; Lindhoff-Last, Edelgard

    2010-04-01

    Residual platelet function despite treatment with clopidogrel may predict an unfavourable cardiovascular outcome. The majority of studies have investigated the effects of clopidogrel administration in conjunction with aspirin in patients undergoing percutaneous coronary intervention. The primary objective of the present study was to assess the platelet response to clopidogrel in the absence of aspirin in patients with peripheral arterial occlusive disease (PAOD) and to investigate whether non-responsiveness to clopidogrel is reproducible during long-term follow-up. Fifty-four clinically stable PAOD patients on a maintenance dose of 75 mg/d clopidogrel were enrolled in this study. Platelet function was assessed at baseline and after a median follow-up of 18 months using light transmittance aggregometry (LTA) with 2 microM ADP as an agonist. HPLC-coupled mass spectrometry was used to detect clopidogrel and clopidogrel carboxylic acid, the main metabolite of clopidogrel. Residual platelet function, as defined by late aggregation values within the reference range (i.e., >43%), was observed in 35.2% of patients at baseline and 17.6% during follow-up. During the observation period, 26.5% had switched from responder to non-responder status or vice versa. Among non-responders, either clopidogrel or its metabolite was detected in 89.5% and 83.3% of patients at baseline and at follow-up, respectively. We conclude that non-responsiveness to clopidogrel as determined by ADP-induced LTA is not stable over time. This phenomenon cannot be attributed to non-compliance alone. PMID:20153859

  4. 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

  5. Identification of Functional Voltage-gated Na+ Channels in Cultured Human Pulmonary Artery Smooth Muscle Cells

    PubMed Central

    Sison, Tiffany; Yuan, Jason X.-J.

    2005-01-01

    Electrical excitability, which plays an important role in excitation-contraction coupling in the pulmonary vasculature, is regulated by transmembrane ion flux in pulmonary artery smooth muscle cells (PASMC). This study aimed to characterize the electrophysiological properties and molecular identities of voltage-gated Na+ channels in cultured human PASMC. We recorded tetrodotoxin-sensitive and rapidly inactivating Na+ currents with properties similar to those described in cardiac myocytes. Using RT-PCR, we detected transcripts of seven Na+ channel α genes (SCN2A, 3A, 4A, 7A, 8A, 9A, and 11A), and two β subunit genes (SCN1B and 2B). Our results demonstrate that human PASMC express TTX-sensitive voltage-gated Na+ channels. Their physiological functions remain unresolved, although our data suggest that Na+ channel activity does not directly influence membrane potential, intracellular Ca2+ release, or proliferation in normal human PASMC. Whether their expression and/or activity are heightened in the pathological state is discussed. PMID:16052353

  6. Low levels of adiponectin predict worsening of arterial morphology and function.

    PubMed

    Störk, Stefan; Bots, Michiel L; Angerer, Peter; von Schacky, Clemens; Grobbee, Diederick E; Angermann, Christiane E; Seufert, Jochen

    2007-10-01

    Adipocytokines are under investigation as mediators of cardiovascular risk. In 142 non-diabetic postmenopausal women, we investigated whether plasma levels of adiponectin and leptin are associated with changes in carotid intima-media thickness (IMT) and distensibility as assessed by high-resolution ultrasound. Adiponectin but not leptin correlated weakly with baseline measures of IMT and distensibility. After 12 months, carotid IMT showed a significant progression [0.023 mm (95% CI, 0.014-0.031 mm)] whereas stiffness was unaltered. A threshold was identified for the relation of adiponectin with both progression of IMT and stiffness. Age-adjusted adiponectin levels in the lowest quartile versus second to fourth quartile were related to progression of IMT (odds ratio, 2.99; 95% CI, 1.81-5.09) and stiffness (odds ratio, 1.71; 95% CI, 1.19-4.07). Adjustment for possible confounding factors and intermediates weakened this association only to a minor degree. No such associations were observed for leptin. We conclude that low levels of adiponectin are associated with adverse changes in morphology and function of central arteries over time independently of other cardiovascular risk factors in postmenopausal non-diabetic women. PMID:17239889

  7. Functional reconstitution of receptors for bradykinin and des argZ-bradykinin from pulmonary artery membranes

    SciTech Connect

    Cahill, M.C.; Polgar, P.; Dickey, B.F.; Fishman, J.B.

    1987-05-01

    Bradykinin (BK) is a vasoactive peptide which mediates a number of vascular functions, including activation of prostaglandin biosynthesis and modulation of vasomotor tone. BK and its kinase II metabolite, des argZ-BK, have been reported to activate the B2 and B1 receptors, respectively. The authors prepared membranes from the bovine pulmonary artery and solubilized membrane proteins using the zwitterionic detergent CHAPS (3-((3-cholamidopropyl) dimethylammonio)-1-propanesulfonate). The solubilized proteins were reconstituted into liposomes via a gel filtration method. The vesicles specifically bound both TH-BK and TH-des argZ-BK, although the latter bound with significantly lower affinity. The binding of TH-BK was inhibited 65% by guanosine 5'-0-thiotriphosphate S while the binding of TH-des argZ-BK was unaffected. This suggests that the receptor for BK was associated with a guanine-nucleotide binding protein whereas the receptor for des argZ-BK was not. Since des argZ-BK has recently been reported to be considerably less potent than BK at activating the turnover of phosphatidylinositol, the authors data suggest that this is due to the des argZ-BK receptor not being coupled to a G-protein. Further work towards characterizing these receptors is now underway.

  8. Mutant LRP6 Impairs Endothelial Cell Functions Associated with Familial Normolipidemic Coronary Artery Disease.

    PubMed

    Guo, Jian; Li, Yang; Ren, Yi-Hong; Sun, Zhijun; Dong, Jie; Yan, Han; Xu, Yujun; Wang, Dao Wen; Zheng, Gu-Yan; Du, Jie; Tian, Xiao-Li

    2016-01-01

    Mutations in the genes low-density lipoprotein (LDL) receptor-related protein-6 (LRP6) and myocyte enhancer factor 2A (MEF2A) were reported in families with coronary artery disease (CAD). We intend to determine the mutational spectrum of these genes among hyperlipidemic and normolipidemic CAD families. Forty probands with early-onset CAD were recruited from 19 hyperlipidemic and 21 normolipidemic Chinese families. We sequenced all exons and intron-exon boundaries of LRP6 and MEF2A, and found a novel heterozygous variant in LRP6 from a proband with normolipidemic CAD. This variant led to a substitution of histidine to tyrosine (Y418H) in an evolutionarily conserved domain YWTD in exon 6 and was not found in 1025 unrelated healthy individuals. Co-segregated with CAD in the affected family, LRP6Y418H significantly debilitated the Wnt3a-associated signaling pathway, suppressed endothelial cell proliferation and migration, and decreased anti-apoptotic ability. However, it exhibited no influences on low-density lipoprotein cholesterol uptake. Thus, mutation Y418H in LRP6 likely contributes to normolipidemic familial CAD via impairing endothelial cell functions and weakening the Wnt3a signaling pathway. PMID:27455246

  9. Mutant LRP6 Impairs Endothelial Cell Functions Associated with Familial Normolipidemic Coronary Artery Disease

    PubMed Central

    Guo, Jian; Li, Yang; Ren, Yi-Hong; Sun, Zhijun; Dong, Jie; Yan, Han; Xu, Yujun; Wang, Dao Wen; Zheng, Gu-Yan; Du, Jie; Tian, Xiao-Li

    2016-01-01

    Mutations in the genes low-density lipoprotein (LDL) receptor-related protein-6 (LRP6) and myocyte enhancer factor 2A (MEF2A) were reported in families with coronary artery disease (CAD). We intend to determine the mutational spectrum of these genes among hyperlipidemic and normolipidemic CAD families. Forty probands with early-onset CAD were recruited from 19 hyperlipidemic and 21 normolipidemic Chinese families. We sequenced all exons and intron-exon boundaries of LRP6 and MEF2A, and found a novel heterozygous variant in LRP6 from a proband with normolipidemic CAD. This variant led to a substitution of histidine to tyrosine (Y418H) in an evolutionarily conserved domain YWTD in exon 6 and was not found in 1025 unrelated healthy individuals. Co-segregated with CAD in the affected family, LRP6Y418H significantly debilitated the Wnt3a-associated signaling pathway, suppressed endothelial cell proliferation and migration, and decreased anti-apoptotic ability. However, it exhibited no influences on low-density lipoprotein cholesterol uptake. Thus, mutation Y418H in LRP6 likely contributes to normolipidemic familial CAD via impairing endothelial cell functions and weakening the Wnt3a signaling pathway. PMID:27455246

  10. Arterial input functions (AIFs) measured directly from arteries with low and standard doses of contrast agent, and AIFs derived from reference tissues

    PubMed Central

    Wang, Shiyang; Fan, Xiaobing; Medved, Milica; Pineda, Federico D.; Yousuf, Ambereen; Oto, Aytekin; Karczmar, Gregory S.

    2016-01-01

    Measurements of arterial input function (AIF) can have large systematic errors at standard contrast agent doses in dynamic contrast enhanced MRI (DCE-MRI). We compared measured AIFs from low dose (AIFLD) and standard dose (AIFSD) contrast agent injections, as well as the AIF derived from a muscle reference tissue and artery (AIFref). Twenty-two prostate cancer patients underwent DCE-MRI. Data were acquired on a 3 T scanner using an mDixon sequence. Gadobenate dimeglumine was injected twice, at doses of 0.015 and 0.085 mmol/kg. Directly measured AIFs were fitted with empirical mathematical models (EMMs) and compared to the AIF derived from a muscle reference tissue (AIFref). EMMs accurately fitted the AIFs. The 1st and 2nd pass peaks were visualized in AIFLD, but not in AIFSD, thus the peak and shape of AIFSD could not be accurately measured directly. The average scaling factor between AIFSD and AIFLD in the washout phase was only 56% of the contrast dose ratio (~6:1). The shape and magnitude of AIFref closely approximated that of AIFLD after empirically determined dose-dependent normalization. This suggests that AIFref may be a good approximation of the local AIF. PMID:26523650

  11. Functional characterization of voltage-gated K+ channels in mouse pulmonary artery smooth muscle cells.

    PubMed

    Ko, Eun A; Burg, Elyssa D; Platoshyn, Oleksandr; Msefya, Joseph; Firth, Amy L; Yuan, Jason X-J

    2007-09-01

    Mice are useful animal models to study pathogenic mechanisms involved in pulmonary vascular disease. Altered expression and function of voltage-gated K(+) (K(V)) channels in pulmonary artery smooth muscle cells (PASMCs) have been implicated in the development of pulmonary arterial hypertension. K(V) currents (I(K(V))) in mouse PASMCs have not been comprehensively characterized. The main focus of this study was to determine the biophysical and pharmacological properties of I(K(V)) in freshly dissociated mouse PASMCs with the patch-clamp technique. Three distinct whole cell I(K(V)) were identified based on the kinetics of activation and inactivation: rapidly activating and noninactivating currents (in 58% of the cells tested), rapidly activating and slowly inactivating currents (23%), and slowly activating and noninactivating currents (17%). Of the cells that demonstrated the rapidly activating noninactivating current, 69% showed I(K(V)) inhibition with 4-aminopyridine (4-AP), while 31% were unaffected. Whole cell I(K(V)) were very sensitive to tetraethylammonium (TEA), as 1 mM TEA decreased the current amplitude by 32% while it took 10 mM 4-AP to decrease I(K(V)) by a similar amount (37%). Contribution of Ca(2+)-activated K(+) (K(Ca)) channels to whole cell I(K(V)) was minimal, as neither pharmacological inhibition with charybdotoxin or iberiotoxin nor perfusion with Ca(2+)-free solution had an effect on the whole cell I(K(V)). Steady-state activation and inactivation curves revealed a window K(+) current between -40 and -10 mV with a peak at -31.5 mV. Single-channel recordings revealed large-, intermediate-, and small-amplitude currents, with an averaged slope conductance of 119.4 +/- 2.7, 79.8 +/- 2.8, 46.0 +/- 2.2, and 23.6 +/- 0.6 pS, respectively. These studies provide detailed electrophysiological and pharmacological profiles of the native K(V) currents in mouse PASMCs. PMID:17581857

  12. 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

  13. 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. PMID:21357503

  14. 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.

  15. 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. PMID:27035874

  16. Translational informatics approach for identifying the functional molecular communicators linking coronary artery disease, infection and inflammation

    PubMed Central

    SHARMA, ANKIT; GHATGE, MADANKUMAR; MUNDKUR, LAKSHMI; VANGALA, RAJANI KANTH

    2016-01-01

    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 identifed 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. PMID:27035874

  17. Preservation of retinal structure and function after cilioretinal artery occlusion: a case report.

    PubMed

    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

  18. 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

  19. Cardiac structure and function, and ventricular-arterial interaction 11 years following a pregnancy with preeclampsia.

    PubMed

    Al-Nashi, Maha; Eriksson, Maria J; Östlund, Eva; Bremme, Katarina; Kahan, Thomas

    2016-04-01

    Preeclampsia (PE) is associated with acute left ventricular dysfunction. Whether these changes eventually resolve remains unclear. This study assessed left and right ventricular structure and function, and ventricular-arterial interaction in 15 women 11 years after a pregnancy with PE and 16 matched control subjects with a normal pregnancy. We found normal left and right ventricular dimensions, systolic function, and global left ventricular strain, with no differences between the groups. In addition, indices of diastolic function, left and right atrial size, and amino-terminal pro-brain natriuretic peptide were normal and did not differ between the groups. Women with a previous PE had impaired night/day ratios for systolic and diastolic ambulatory blood pressure. However, indices of aortic stiffness or ventricular-arterial coupling did not differ between the groups. In conclusion, we could not demonstrate remaining alterations in systolic or diastolic left or right ventricular function, or in ventricular-arterial interaction in women 11 years after PE. PMID:26852291

  20. Weight Loss Alone Improves Conduit and Resistance Artery Endothelial Function in Young and Older Overweight/Obese Adults

    PubMed Central

    Pierce, Gary L.; Beske, Stacy D.; Lawson, Brooke R.; Southall, Kara L.; Benay, Francoise J.; Donato, Anthony J.; Seals, Douglas R.

    2010-01-01

    Obesity is associated with vascular endothelial dysfunction, as indicated by impaired endothelium-dependent dilation (EDD). Presently there is no direct evidence that energy intake restricted weight loss alone improves conduit or resistance artery EDD, the mechanisms involved, or if improvements differ with patient age. A total of 40 overweight or obese (body mass index ≥ 25<40 kg/m2) non-diabetic men and women aged 21–69 years completed 12 weeks of reduced energy intake (n=26, 15M) or attention control (n=14, 9M) and 4 weeks of weight maintenance (randomized trial). Energy intake restriction reduced estimated total energy intake (33%), body weight (10.5%), total and abdominal body fat, plasma leptin, oxidized LDL, and improved some metabolic risk factors. Brachial artery flow mediated dilation (FMD) was increased by 30% (6.0 ± 0.7 vs. 7.9 ± 0.7 % Δ, P=0.01, n=17). Peak forearm blood flow during intra-brachial artery infusion of acetylcholine was increased by 26% (16.8 ± 1.4 vs. 21.1± 1.9 ml/100ml/min, P<0.05, n=15); this was inversely related to the reduction in abdominal visceral:subcutaneous fat ratio (r=−0.46, P<0.05) and was abolished by inhibition of nitric oxide synthesis with Ng-monomethyl L-arginine. Improvements in EDD were not related to age: mean increases in subjects >50 years were similar to or greater than those <50. Energy intake restricted weight loss alone is an effective intervention for improving peripheral conduit and resistance artery endothelial function in young and older overweight/obese adults. The improvements in resistance artery function are mediated by an increase in nitric oxide bioavailability and are related to reductions in abdominal visceral fat. PMID:18504322

  1. Monitoring changes in heart tissue temperature and evaluation of graft function after coronary artery bypass grafting surgery.

    PubMed

    Lekas, Raimundas; Jakuska, Povilas; Krisciukaitis, Algimantas; Veikutis, Vincentas; Dzemyda, Gintautas; Mickevicius, Tomas; Morkūnaite, Kristina; Vilke, Alina; Treigys, Povilas; Civinskiene, Genuvaite; Andriuskevicius, Jonas; Vanagas, Tomas; Skauminas, Kestutis; Bernatoniene, Jurga

    2009-01-01

    Thermography is a relatively new contact-free method used in experimental and clinical studies and in cardiovascular surgery to investigate the myocardium and coronary artery function. Objects of complex study included mongrel dogs and patients with coronary artery disease who underwent cardiac surgery. For active dynamic thermography, we used a thermovision camera "A20V" (FLIR Systems, USA). Our data indicate that both experimental and clinical study performed on beating hearts could be an important approach to interoperation inspection of autovenous graft function. An infrared camera also can be successfully used to determine the extent of ischemic damage to the myocardium, heart, and blood vessels during surgery as a significant prognostic tool for evaluating outcome after cardiac operation. PMID:19357452

  2. [Coronary artery disease, myocardial perfusion and ventricular function in Q-wave and non-Q-wave myocardial infarcts].

    PubMed

    Macieira-Coelho, E; Garcia-Alves, M; da Costa, B; Cantinho, G; Pedro, P; Dionisio, I; Gouveia, A; de Padua, F

    1997-04-01

    Controversy remains in considering non-Q wave myocardial infarction (NQMI) a distinct pathophysiological entity of Q wave myocardial infarction (QMI). In order to analyze the severity of coronary artery disease, extension of myocardial scar or myocardial ischemia and ventricular function, 78 consecutive patients with QMI and 32 with NQMI, mean age 55.4 +/- 8.5, not submitted to thrombolytic therapy, were studied. Coronary angiography, exercise thallium scintigraphy and radionuclide ventriculography were performed in all at least within 3 months of a prior myocardial infarction. In the present study the occurrence of QMI was significantly more frequent in older patients than NQMI. There was no prevalence of occlusion either in the right, left circumflex or left anterior descending coronary arteries in both groups. Ejection fraction, degree of occlusion and presence of collateral circulation showed an equal prevalence in QMI and NQMI patients. A higher incidence of multivessel disease was found in NQMI that had less necrosis than QMI patients. The prevalence of exercise induced thallium-201 redistribution defects within the infarct zone was substantially higher and involved more scar segments in NQMI patients. Physiological and clinical consequences of coronary thrombosis depends on the size and the number of diseased arteries, the approach the pathophysiologic consequences of coronary disease in terms of fractal structure has been suggested. A pronounced heterogeneity in regional myocardial blood flow in a fractal branching arterial network may be responsible for the pathophysiologic differences of coronary thrombosis between Q-wave and non Q-wave infarction. PMID:9341032

  3. Resveratrol Decreases TXNIP mRNA and Protein Nuclear Expressions With an Arterial Function Improvement in Old Mice.

    PubMed

    Bedarida, Tatiana; Baron, Stephanie; Vibert, Françoise; Ayer, Audrey; Henrion, Daniel; Thioulouse, Elizabeth; Marchiol, Carmen; Beaudeux, Jean-Louis; Cottart, Charles-Henry; Nivet-Antoine, Valerie

    2016-06-01

    Aging leads to a high prevalence of glucose intolerance and cardiovascular diseases, with oxidative stress playing a potential role. Resveratrol has shown promising effects on glucose tolerance and tends to improve endothelial function in elderly patients. Thioredoxin-interacting protein (TXNIP) was recently proposed as a potential link connecting glucose metabolism to oxidative stress. Here, we investigated the resveratrol-induced improvement of arterial aging phenotype in old mice and the expression of aortic TXNIP. Using an in vivo model of old mice with or without 3-month resveratrol treatment, we investigated the effects of resveratrol on age-related impairments from a cardiovascular Doppler analysis, to a molecular level, by studying inflammation and oxidative stress factors. We found a dual effect of resveratrol, with a decrease of age-related glucose intolerance and oxidative stress imbalance leading to reduced matrix remodeling that forestalls arterial aging phenotype in terms of intima-media thickness and arterial distensibility. These results provide the first evidence that aortic TXNIP mRNA and protein nuclear expressions are increased in the arterial aging and decreased by resveratrol treatment. In conclusion, we demonstrated that resveratrol helped to restore several aging impaired processes in old mice, with a decrease of aortic TXNIP mRNA and protein nuclear expressions. PMID:26041427

  4. Kinetic quantitation of cerebral PET-FDG studies without concurrent blood sampling: statistical recovery of the arterial input function.

    PubMed

    O'Sullivan, F; Kirrane, J; Muzi, M; O'Sullivan, J N; Spence, A M; Mankoff, D A; Krohn, K A

    2010-03-01

    Kinetic quantitation of dynamic positron emission tomography (PET) studies via compartmental modeling usually requires the time-course of the radio-tracer concentration in the arterial blood as an arterial input function (AIF). For human and animal imaging applications, significant practical difficulties are associated with direct arterial sampling and as a result there is substantial interest in alternative methods that require no blood sampling at the time of the study. A fixed population template input function derived from prior experience with directly sampled arterial curves is one possibility. Image-based extraction, including requisite adjustment for spillover and recovery, is another approach. The present work considers a hybrid statistical approach based on a penalty formulation in which the information derived from a priori studies is combined in a Bayesian manner with information contained in the sampled image data in order to obtain an input function estimate. The absolute scaling of the input is achieved by an empirical calibration equation involving the injected dose together with the subject's weight, height and gender. The technique is illustrated in the context of (18)F -Fluorodeoxyglucose (FDG) PET studies in humans. A collection of 79 arterially sampled FDG blood curves are used as a basis for a priori characterization of input function variability, including scaling characteristics. Data from a series of 12 dynamic cerebral FDG PET studies in normal subjects are used to evaluate the performance of the penalty-based AIF estimation technique. The focus of evaluations is on quantitation of FDG kinetics over a set of 10 regional brain structures. As well as the new method, a fixed population template AIF and a direct AIF estimate based on segmentation are also considered. Kinetics analyses resulting from these three AIFs are compared with those resulting from radially sampled AIFs. The proposed penalty-based AIF extraction method is found to

  5. Baroreceptor reflex during forced expiratory maneuvers in individuals with chronic spinal cord injury.

    PubMed

    Legg Ditterline, Bonnie E; Aslan, Sevda C; Randall, David C; Harkema, Susan J; Ovechkin, Alexander V

    2016-07-15

    Pulmonary and cardiovascular dysfunctions are leading causes of morbidity and mortality in patients with chronic Spinal Cord Injury (SCI). Impaired respiratory motor function and decreased Baroreflex Sensitivity (BS) are predictors for the development of cardiopulmonary disease. This observational case-controlled clinical study was undertaken to investigate if respiratory motor control deficits in individuals with SCI affect their ability to perform the Valsalva maneuver, and to determine if a sustained Maximum Expiratory Pressure (MEP) effort can serve as an acceptable maneuver for determination of the BS in the event that the Valsalva maneuver cannot be performed. The BS outcomes (ms/mmHg) were obtained using continuous beat-to-beat arterial blood pressure (BP) and heart rate (HR) recordings during Valsalva or MEP maneuvers in thirty nine individuals with chronic C3-T12 SCI. Twenty one participants (54%) reported signs of intolerance during the Valsalva maneuver and only 15 individuals (39%) were able to complete this task. Cervical level of injury was a significant risk factor (p=0.001) for failing to complete the Valsalva maneuver, and motor-complete injury was a significant risk factor for symptoms of intolerance (p=0.04). Twenty eight participants (72%) were able to perform the MEP maneuver; the other 11 participants failed to exceed the standard airway pressure threshold of 27cm H2O. Neither level nor completeness of injury were significant risk factors for failure of MEP maneuver. When the required airway pressure was sustained, there were no significant differences between BS outcomes obtained during Valsalva and MEP maneuvers. The results of this study indicate that individuals with high-level and motor-complete SCI are at increased risk of not completing the Valsalva maneuver and that baroreflex-mediated responses can be evaluated by using sustained MEP maneuver when the Valsalva maneuver cannot be performed. PMID:27137412

  6. Effects of Clopidogrel Therapy on Oxidative Stress, Inflammation, Vascular Function and Progenitor Cells in Stable Coronary Artery Disease

    PubMed Central

    Ramadan, Ronnie; Dhawan, Saurabh S.; Syed, Hamid; Pohlel, F. Khan; Binongo, Jose Nilo G.; Ghazzal, Ziyad B.; Quyyumi, Arshed A.

    2014-01-01

    Background Traditional cardiovascular risk factors lead to endothelial injury and activation of leucocytes and platelets that initiate and propagate atherosclerosis. We proposed that clopidogrel therapy in patients with stable CAD imparts a pleiotropic effect that extends beyond anti-platelet aggregation to other athero-protective processes. Methods Forty-one subjects were randomized in a double-blind, placebo-controlled crossover study to either clopidogrel 75 mg daily or placebo for 6-weeks, and then transitioned immediately to the other treatment for an additional 6 weeks. We assessed 1) endothelial function as flow-mediated dilation of the brachial artery, 2) arterial stiffness and central augmentation index using applanation tonometry, 3) vascular function as fingertip reactive hyperemia index, 4) inflammation by measuring plasma CD40 ligand and serum high-sensitivity c-reactive protein levels, 5) oxidative stress by measuring plasma aminothiols, and 6) circulating progenitor cells, at baseline and at the end of each 6-week treatment period. Results Clopidogrel therapy resulted in a significant reduction in soluble CD40 ligand (p=0.03), a pro-thrombotic and pro-inflammatory molecule derived mainly from activated platelets. However, clopidogrel therapy had no effect on endothelial function, arterial stiffness, inflammatory and oxidative stress markers, or progenitor cells. Conclusions Our findings suggest a solitary anti-platelet effect of clopidogrel therapy in patients with stable CAD, with no effect on other sub-clinical markers of cardiovascular disease risk. PMID:24336012

  7. Direct binding and functional studies on muscarinic cholinoceptors in porcine coronary artery.

    PubMed

    Yamada, S; Yamazawa, T; Nakayama, K

    1990-02-01

    The muscarinic cholinoceptors in porcine coronary artery were identified and characterized by a binding assay using (-)-[3H]quinuclidinyl benzilate (QNB) and also by pharmacological method. Specific (-)-[3H]QNB binding in the coronary artery was saturable and of high affinity (Kd = 0.08 nM), and it showed a pharmacological specificity as well as stereoselectivity which characterized muscarinic receptors. Muscarinic antagonists competed with the (-)-[3H]QNB binding in order: nonlabeled QNB greater than dexetimide greater than atropine greater than pirenzepine greater than AF-DX 116 greater than levetimide greater than gallamine. Dexetimide was approximately 2000 times as potent as levetimide. The potencies (pKi) of these muscarinic antagonists in competing for (-)-[3H]QNB binding sites in porcine coronary artery correlated well with their pharmacological potencies (pA2 for antagonistic effect of acetylcholine-induced contraction of coronary artery). The decrease in the (-)-[3H]QNB binding by atropine and pirenzepine was due to a reduction in the apparent affinity with little change in the number of maximal binding sites, suggesting a competitive antagonism. Specific (-)-[3H]QNB binding (Kd and maximal number of binding sites) in porcine coronary artery was not changed by the removal of endothelium. We conclude: 1) (-)-[3H]QNB selectively labels the physiologically relevant muscarinic receptors in porcine coronary artery and 2) the majority of these receptors is localized on vascular smooth muscles and the receptors mediate the acetylcholine-induced contractile response of coronary artery. PMID:2313599

  8. Echocardiographic assessment of right ventricular functions in patients with proximal right coronary artery chronic total occlusion.

    PubMed

    Missiri, Ahmed Mohamed El; Guindy, Ramez Raouf

    2016-06-01

    To assess right ventricular functions by echocardiography in patients with proximal right coronary artery (RCA) CTO and correlating it with clinical and angiographic variables. We studied 60 consecutive patients with CTO of the proximal RCA and no other significant lesions in the left coronary system. Echocardiography was performed in order to measure left ventricular (LV) dimensions, LVEF, RV end diastolic area (RVEDA), RV end systolic area (RVESA), RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), Doppler myocardial performance index (MPI), trans-tricuspid E and A waves, E/A ratio, S', e' and a'. Grades of coronary collaterals was assessed. Doppler MPI showed negative correlation with TAPSE (r = -0.8997, p < 0.0001) and RVFAC (r = -0.928, p < 0.0001). Positive correlation with trans-tricuspid E/A ratio (r = 0.893, p < 0.0001) and E/e' ratio (r = 0.783, p < 0.0001). Patients with no evidence of MI had more well-developed (grade 3) coronary collaterals (83.8 vs. 17.4 %). Patients with evidence of MI had lower RVFAC 38.13 ± 5.39 versus 45.08 ± 4.99 % (p < 0.0001), lower TAPSE 20.17 ± 3.85 versus 25.35 ± 3.46 mm (p < 0.0001), higher MPI 0.4 ± 0.08 versus 0.31 ± 0.05 (p < 0.0001), higher trans-tricuspid E/A ratio 1.79 ± 0.38 versus 1.13 ± 0.36 (p < 0.0001) and E/e' ratio 5.23 ± 1.02 versus 3.61 ± 0.88 (p < 0.0001). Patients with poorly developed collaterals had lower TAPSE and RVFAC and a higher MPI (p < 0.0001 for each). Patients with proximal RCA CTOs and evidence of inferior wall MI have significant impairment of RV functions in addition to poorly developed coronary collaterals. Those with proximal RCA CTOs and well-developed coronary collaterals have better RV functions. PMID:26850438

  9. Do preoperative pulmonary function indices predict morbidity after coronary artery bypass surgery?

    PubMed Central

    Najafi, Mahdi; Sheikhvatan, Mehrdad; Mortazavi, Seyedeh Hamideh

    2015-01-01

    Context: The reported prevalence of chronic obstructive pulmonary disease (COPD) varies among different groups of cardiac surgical patients. Moreover, the prognostic value of preoperative COPD in outcome prediction is controversial. Aims: The present study assessed the morbidity in the different levels of COPD severity and the role of pulmonary function indices in predicting morbidity in patients undergoing coronary artery bypass graft (CABG). Settings and Design: Patients who were candidates for isolated CABG with cardiopulmonary bypass who were recruited for Tehran Heart Center-Coronary Outcome Measurement Study. Methods: Based on spirometry findings, diagnosis of COPD was considered based on Global Initiative for Chronic Obstructive Lung Disease category as forced expiratory volume in 1 s [FEV1]/forced vital capacity <0.7 (absolute value, not the percentage of the predicted). Society of Thoracic Surgeons (STS) definition was used for determining COPD severity and the patients were divided into three groups: Control group (FEV1 >75% predicted), mild (FEV1 60–75% predicted), moderate (FEV1 50–59% predicted), severe (FEV1<50% predicted). The preoperative pulmonary function indices were assessed as predictors, and postoperative morbidity was considered the surgical outcome. Results: This study included 566 consecutive patients. Patients with and without COPD were similar regarding baseline characteristics and clinical data. Hypertension, recent myocardial infarction, and low ejection fraction were higher in patients with different degrees of COPD than the control group while male gender was more frequent in control patients than the others. Restrictive lung disease and current cigarette smoking did not have any significant impact on postoperative complications. We found a borderline P = 0.057 with respect to respiratory failure among different patients of COPD severity so that 14.1% patients in control group, 23.5% in mild, 23.4% in moderate, and 21.9% in severe

  10. The effect of hypoxia-induced intrauterine growth restriction on renal artery function.

    PubMed

    Verschuren, M T C; Morton, J S; Abdalvand, A; Mansour, Y; Rueda-Clausen, C F; Compston, C A; Luyckx, V; Davidge, S T

    2012-10-01

    The risk of developing cardiovascular diseases is known to begin before birth and the impact of the intrauterine environment on subsequent adult health is currently being investigated from many quarters. Following our studies demonstrating the impact of hypoxia in utero and consequent intrauterine growth restriction (IUGR) on the rat cardiovascular system, we hypothesized that changes extend throughout the vasculature and alter function of the renal artery. In addition, we hypothesized that hypoxia induces renal senescence as a potential mediator of altered vascular function. We demonstrated that IUGR females had decreased responses to the adrenergic agonist phenylephrine (PE; pEC50 6.50 ± 0.05 control v. 6.17 ± 0.09 IUGR, P < 0.05) and the endothelium-dependent vasodilator methylcholine (MCh; E max 89.8 ± 7.0% control v. 41.0 ± 6.5% IUGR, P < 0.001). In IUGR females, this was characterised by increased basal nitric oxide (NO) modulation of vasoconstriction (PE pEC50 6.17 ± 0.09 IUGR v. 6.42 ± 0.08 in the presence of the NO synthase inhibitor N-nitro-l-arginine methyl ester hydrochloride (l-NAME; P < 0.01) but decreased activated NO modulation (no change in MCh responses in the presence of l-NAME), respectively. In contrast, IUGR males had no changes in PE or MCh responses but demonstrated increased basal NO (PE pEC50 6.29 ± 0.06 IUGR v. 6.42 ± 0.12 plus l-NAME, P < 0.01) and activated NO (E max 37.8 ± 9.4% control v. -0.8 ± 13.0% plus l-NAME, P < 0.05) modulation. No significant changes were found in gross kidney morphology, proteinuria or markers of cellular senescence in either sex. In summary, renal vascular function was altered by hypoxia in utero in a sex-dependent manner but was unlikely to be mediated by premature renal senescence. PMID:25102262

  11. Nogo-B Receptor Modulates Pulmonary Artery Smooth Muscle Cell Function in Developing Lungs.

    PubMed

    Tadokoro, Kent S; Rana, Ujala; Jing, Xigang; Konduri, G Ganesh; Miao, Qing R; Teng, Ru-Jeng

    2016-06-01

    Nogo-B and its receptor (NgBR) are involved in blood vessel growth in developing lungs, but their role in pulmonary artery smooth muscle cell (PASMC) growth is unknown. We hypothesized that NgBR regulates growth of PASMCs by modulating the function of endoplasmic reticulum (ER) and formation of reactive oxygen species (ROS). In utero constriction of the ductus arteriosus created pulmonary hypertension in fetal lambs (hypertensive fetal lamb [HTFL]). PASMCs isolated 8 days after surgery were assessed for the alteration of protein levels by immunoblots and ROS formation by dihydroethidium and Cell ROX deep red fluorescence. NgBR small interfering RNA and plasmid DNA were used to manipulate NgBR levels. Proliferation and wound healing were assessed by cell counts and scratch recovery assay, respectively. Acute ER stress was induced by tunicamycin. Differences of mitogen-activated protein kinase and Akt pathway activation in HTFL versus control PASMCs were evaluated. Results showed that HTFL PASMCs had decreased NgBR levels and increased proliferation, wound healing, ER stress, and ROS formation compared with controls. Knockdown of NgBR in control PASMCs generated a phenotype similar to HTFL, and overexpression in HTFL restored the defective phenotype to control. Decreased NgBR levels were associated with increased ROS formation in HTFL PASMCs. Subsequently, scavenging ROS decreased proliferation and wound healing. Mechanistically, ROS formation decreases NgBR expression, which induces ER stress. This leads to extracellular signal-regulated kinase pathway activation and PASMC phenotype alteration. Our data suggest that decreased NgBR expression in pulmonary hypertension of the newborn contributes to increased PASMC proliferation and oxidative stress, which lead to the pathogenesis of lung injury. PMID:26652754

  12. Coronary Artery Calcium and Physical Function in Older Adults: The Cardiovascular Health Study

    PubMed Central

    Inzitari, Marco; Naydeck, Barbara L.; Newman, Anne B.

    2016-01-01

    Background In older adults without clinical cardiovascular disease, coronary artery calcium (CAC) is associated with other subclinical vascular diseases, which, in turn, predict physical dysfunction. However, the association between CAC and physical function is unstudied. Methods In 387 older community-dwellers from the Cardiovascular Health Study without clinical cardiovascular diseases (mean age ± standard deviation = 78.7 ± 3.7, 35% men, 22% African Americans), CAC was measured using electron beam tomography, and physical performance was assessed by usual pace gait speed, chair stand, and tandem stand. Differences in physical performance across CAC quartiles were investigated in the whole cohort and by gender. Associations with gait speed (m/s) were assessed in multivariable models using both the continuous form of CAC score (log(CAC)) and quartiles of CAC, adjusting for demographics and comorbidities. Results No differences in physical performance were observed across CAC quartiles in the whole group. In gender-stratified analyses, a significant association was shown among women, who had progressively lower gait speed across CAC quartiles: Those with CAC > 220 walked more than 0.1 m/s slower than those with CAC < 35 (age-adjusted ptrend =.017). After multivariable adjustment, the association remained statistically significant for women in both linear (log(CAC) and gait speed, p =.025) and logistic models: Each of the top three CAC quartiles (35–220, 221–659, and ≥660) had a more than twofold odds of walking slower than 1 m/s, compared to the lowest CAC quartile (< 35; p =.021). Conclusions In this sample of older community-dwellers without overt cardiovascular disease, CAC was inversely related to gait speed in women, but not in men. PMID:18948563

  13. Intrapericardial denervation - Radial artery blood flow and heart rate responses to LBNP

    NASA Technical Reports Server (NTRS)

    Mckeever, Kenneth H.; Skidmore, Michael G.; Keil, Lanny C.; Sandler, Harold

    1990-01-01

    The effects of intrapericardial denervation on the radial artery blood flow velocity (RABFV) and heart rate (HR) responses to LBNP in rhesus monkeys were investigated by measuring the RABFV transcutaneously by a continuous-wave Doppler ultrasonic flowmeter in order to derive an index of forearm blood flow response to low (0 to -20 mm Hg) and high (0 to -60 mm Hg) ramp exposures during supine LBNP. Four of the eight subjects were subjected to efferent and afferent cardiac denervation. It was found that, during low levels of LBNP, monkeys with cardiac denervation exhibited no cardiopulmonary baroreceptor-mediated change in the RABFV or HR, unlike the intact animals, which showed steady decreases in RABFV during both high- and low-pressure protocols. It is suggested that forearm blood flow and HR responses to low-level LBNP, along with pharmacological challenge, are viable physiological tests for verifying the completeness of atrial and cardiopulmonary baroreceptor denervation.

  14. Arterial Stiffness

    PubMed Central

    Avolio, Alberto

    2013-01-01

    Stiffness of large arteries has been long recognized as a significant determinant of pulse pressure. However, it is only in recent decades, with the accumulation of longitudinal data from large and varied epidemiological studies of morbidity and mortality associated with cardiovascular disease, that it has emerged as an independent predictor of cardiovascular risk. This has generated substantial interest in investigations related to intrinsic causative and associated factors responsible for the alteration of mechanical properties of the arterial wall, with the aim to uncover specific pathways that could be interrogated to prevent or reverse arterial stiffening. Much has been written on the haemodynamic relevance of arterial stiffness in terms of the quantification of pulsatile relationships of blood pressure and flow in conduit arteries. Indeed, much of this early work regarded blood vessels as passive elastic conduits, with the endothelial layer considered as an inactive lining of the lumen and as an interface to flowing blood. However, recent advances in molecular biology and increased technological sophistication for the detection of low concentrations of biochemical compounds have elucidated the highly important regulatory role of the endothelial cell affecting vascular function. These techniques have enabled research into the interaction of the underlying passive mechanical properties of the arterial wall with the active cellular and molecular processes that regulate the local environment of the load-bearing components. This review addresses these emerging concepts. PMID:26587425

  15. Unique Expression of Angiotensin Type-2 Receptor in Sex-Specific Distribution of Myelinated Ah-Type Baroreceptor Neuron Contributing to Sex-Dimorphic Neurocontrol of Circulation.

    PubMed

    Liu, Yang; Zhou, Jia-Ying; Zhou, Yu-Hong; Wu, Di; He, Jian-Li; Han, Li-Min; Liang, Xiao-Bo; Wang, Lu-Qi; Lu, Xiao-Long; Chen, Hanying; Qiao, Guo-Fen; Shou, Weinian; Li, Bai-Yan

    2016-04-01

    This study aims to understand the special expression patterns of angiotensin-II receptor (AT1R and AT2R) in nodose ganglia and nucleus of tractus solitary of baroreflex afferent pathway and their contribution in sex difference of neurocontrol of blood pressure regulation. In this regard, action potentials were recorded in baroreceptor neurons (BRNs) using whole-cell patch techniques; mRNA and protein expression of AT1R and AT2R in nodose ganglia and nucleus of tractus solitary were evaluated using real time-polymerase chain reaction, Western blot, and immunohistochemistry at both tissue and single-cell levels. The in vivo effects of 17β-estradiol on blood pressure and AT2R expression were also tested. The data showed that AT2R, rather than AT1R, expression was higher in female than age-matched male rats. Moreover, AT2R was downregulated in ovariectomized rats, which was restored by the administration of 17β-estradiol. Single-cell real time-polymerase chain reaction data indicated that AT2R was uniquely expressed in Ah-type BRNs. Functional study showed that long-term administration of 17β-estradiol significantly alleviated the blood pressure increase in ovariectomized rats. Electrophysiological recordings showed that angiotensin-II treatment increased the neuroexcitability more in Ah- than C-type BRNs, whereas no such effect was observed in A-types. In addition, angiotensin-II treatment prolonged action potential duration, which was not further changed by iberiotoxin. The density of angiotensin-II-sensitive K(+) currents recorded in Ah-types was equivalent with iberiotoxin-sensitive component. In summary, the unique, sex- and afferent-specific expression of AT2R was identified in Ah-type BRNs, and AT2R-mediated KCa1.1 inhibition in Ah-type BRNs may exert great impacts on baroreflex afferent function and blood pressure regulation in females. PMID:26883269

  16. Effects of age and sex on cerebrovascular function in the rat middle cerebral artery

    PubMed Central

    2014-01-01

    Background Although the mechanisms underlying the beneficial effects of estrogen on cerebrovascular function are well known, the age-dependent deleterious effects of estrogen are largely unstudied. It was hypothesized that age and sex interact in modulating cerebrovascular reactivity to vasopressin (VP) by altering the role of prostanoids in vascular function. Methods Female (F) Sprague–Dawley rats approximating key stages of “hormonal aging” in humans were studied: premenopausal (mature multigravid, MA, cyclic, 5–6 months) and postmenopausal (reproductively senescent, RS, acyclic, 10–12 months). Age-matched male (M) rats were also studied. Reactivity to VP (10−12–10−7 M) was measured in pressurized middle cerebral artery segments in the absence or presence of selective inhibitors of COX-1 (SC560, SC, 1 μM) or COX-2 (NS398, NS, 10 μM). VP-stimulated release of PGI2 and TXA2 were measured using radioimmunoassay of 6-keto-PGF1α and TXB2 (stable metabolites, pg/mg dry wt/45 min). Results In M, there were no changes in VP-induced vasoconstriction with age. Further, there were no significant differences in basal or in low- or high-VP-stimulated PGI2 or TXA2 production in younger or older M. In contrast, there were marked differences in cerebrovascular reactivity and prostanoid release with advancing age in F. Older RS F exhibited reduced maximal constrictor responses to VP, which can be attributed to enhanced COX-1 derived dilator prostanoids. VP-induced vasoconstriction in younger MA F utilized both COX-1 and COX-2 derived constrictor prostanoids. Further, VP-stimulated PGI2 and TXA2 production was enhanced by endogenous estrogen and decreased with advancing age in F, but not in M rats. Conclusions This is the first study to examine the effects of age and sex on the mechanisms underlying cerebrovascular reactivity to VP. Interestingly, VP-mediated constriction was reduced by age in F, but was unchanged in M rats. Additionally, it was observed

  17. [The biological reaction of inflammation, methylglyoxal of blood plasma, functional and structural alterations in elastic type arteries at the early stage of hypertension disease].

    PubMed

    Titov, V N; Dmitriev, V A; Oshchepkov, E V; Balakhonova, T V; Tripoten', M I; Shiriaeva, Iu K

    2012-08-01

    The article deals with studying of the relationship between biologic reaction of inflammation with glycosylation reaction and content of methylglyoxal in blood serum. The positive correlation between pulse wave velocity and content of methylglyoxal, C-reactive protein in intercellular medium and malleolar brachial index value was established. This data matches the experimental results concerning involvement of biological reaction of inflammation into structural changes of elastic type arteries under hypertension disease, formation of arteries' rigidity and increase of pulse wave velocity. The arterial blood pressure is a biological reaction of hydrodynamic pressure which is used in vivo by several biological functions: biological function of homeostasis, function of endoecology, biological function of adaptation and function of locomotion. The biological reaction of hydrodynamic (hydraulic) pressure is a mode of compensation of derangement of several biological functions which results in the very high rate of hypertension disease in population. As a matter of fact, hypertension disease is a syndrome of lingering pathological compensation by higher arterial blood pressure of the biological functions derangements occurring in the distal section at the level of paracrine cenoses of cells. The arterial blood pressure is a kind of in vivo integral indicator of deranged metabolism. The essential hypertension disease pathogenically is a result of the derangement of three biological functions: biological function of homeostasis, biological function of trophology - nutrition (biological reaction of external feeding - exotrophia) and biological function of endoecology. In case of "littering" of intercellular medium in vivo with nonspecific endogenic flogogens a phylogenetically earlier activation of biological reactions of excretion, inflammation and hydrodynamic arterial blood pressure occur. In case of derangement of biological function of homeostasis, decreasing of

  18. New Insight into Effects of β-Blockers on Arterial Functions

    PubMed Central

    Eguchi, Kazuo

    2016-01-01

    The effects of β-blockers on arterial properties are not well investigated. In our recent study, we compared the effects of the two β-blockers celiprolol and bisoprolol on blood pressure, baroreflex sensitivity (BRS), flow-mediated vasodilatation, and vascular stiffness. We found that bisoprolol achieved a greater reduction in the pulse rate and improved BRS and vascular stiffness, whereas celiprolol reduced the central blood pressure level. In this review, the mechanisms of different types of β-blockers and their effects on arteries are discussed, and the appropriate use of β-blockers in hypertensive subjects will be proposed. PMID:27195240

  19. Preserved structural and functional characteristics of common carotid artery in properly treated normoglycemic women with gestational diabetes mellitus.

    PubMed

    Vastagh, Ildikó; Horváth, T; Garamvölgyi, Z; Rosta, K; Folyovich, A; Rigó, J; Kollai, M; Bereczki, D; Somogyi, A

    2011-09-01

    Women with gestational diabetes mellitus (GDM) are at high risk of subsequently developing type 2 diabetes mellitus which is an important cardiovascular risk factor. We have evaluated whether preclinical morphological and functional arterial changes are present in GDM. Diameter, intima-media thickness (IMT), intima-media cross-section area (IMCSA) and elasticity features (compliance, distensibility coefficient, circumferential strain, stiffness index (SI) α and β, incremental elastic modulus) of the common carotid arteries (CCA) were studied in the 3rd trimester in 25 women with GDM, and 17 normal pregnant women matched for age and body mass index using an ultrasonographic vessel wall-movement tracking system and applanation tonometry. Mean IMT, IMCSA and SI α tended to be larger, whereas compliance was smaller in women with GDM but none of these differences were significant. Serum glucose (4.99 ± 0.51 vs. 4.79 ± 0.61 mmol/L, p=0.37) and HbA1c (5.33 ± 0.27 vs. 5.36 ± 0.47 mmol/L, p=0.85) proved normoglycemia in both groups. In conclusion, by the combination of methods we applied in this case control study, neither morphological nor functional characteristics of large elastic arteries differ significantly between well-treated normoglycemic women with GDM and non-diabetic pregnant women in the 3rd trimester. PMID:21893468

  20. Atherosclerotic renal artery stenosis in the post-CORAL era part 1: the renal penumbra concept and next-generation functional diagnostic imaging.

    PubMed

    Sag, Alan Alper; Inal, Ibrahim; Okcuoglu, John; Rossignol, Patrick; Ortiz, Alberto; Afsar, Baris; Sos, Thomas A; Kanbay, Mehmet

    2016-04-01

    After three neutral trials in which renal artery stenting failed to improve renal function or reduce cardiovascular and renal events, the controversy surrounding diagnosis and treatment of atherosclerotic renal artery stenosis and renovascular hypertension has led to paradigm shifts in the diagnostic algorithm. Noninvasive determination of earlier events (cortex hypoxia and renal artery hemodynamic changes) will supersede late sequelae (calcific stenosis, renal cortical thinning). Therefore, this review proposes the concept of renal penumbra in defining at-risk ischemic renal parenchyma. The complex field of functional renal magnetic resonance imaging will be reviewed succinctly in a clinician-directed fashion. PMID:26944791

  1. 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. PMID:27169859

  2. High dietary fructose does not exacerbate the detrimental consequences of high fat diet on basilar artery function.

    PubMed

    Toklu, H Z; Muller-Delp, J; Sakaraya, Y; Oktay, S; Kirichenko, N; Matheny, M; Carter, C S; Morgan, D; Strehler, K Y E; Tumer, N; Scarpace, P J

    2016-04-01

    The objective of the study was to determine the effects of a high fat (HF) diet alone or with high fructose (HF/F) on functional and structural changes in the basilar arteries and cardiovascular health parameters in rats. Male Sprague Dawley rats were fed either a HF (30%) or HF/F (30/40%) diet for 12 weeks. The basilar artery was cannulated in a pressurized system (90 cm H2O) and vascular responses to KCl (30 - 120 mM), endothelin (10(-11) - 10(-7) M), acetylcholine (ACh) (10(-10) - 10(-4) M), diethylamine (DEA)-NONO-ate (10(-10) - 10(-4) M), and papaverine (10(-10) - 10(-4) M) were evaluated. Rats were also monitored for food intake, body weight, blood lipids, blood pressure, and heart rate. At death, asymmetrical dimethyl arginine level (ADMA) and leptin were assayed in serum. Although there was no significant difference in weight gain and food intake, HF and HF/F diets increased body fat composition and decreased the lean mass. HF/F diet accelerated the development of dyslipidemia. Although resting blood pressure remained unchanged, stress caused a significant elevation in blood pressure and a modest increase in heart rate in HF fed rats. Both HF and HF/F diet resulted in decreased response to endothelium-dependent and -independent relaxation, whereas increased basilar artery wall thickness was observed only in HF group. Serum leptin levels positively correlated with wall thickness. Moreover serum ADMA was increased and eNOS immunofluorescence was significantly decreased with both diets. These data suggest that the presence of high fructose in a HF diet does not exacerbate the detrimental consequences of a HF diet on basilar artery function. PMID:27226180

  3. Characterization of the image-derived carotid artery input function using independent component analysis for the quantitation of [18F] fluorodeoxyglucose positron emission tomography images

    NASA Astrophysics Data System (ADS)

    Chen, K.; Chen, X.; Renaut, R.; Alexander, G. E.; Bandy, D.; Guo, H.; Reiman, E. M.

    2007-12-01

    We previously developed a noninvasive technique for the quantification of fluorodeoxyglucose (FDG) positron emission tomography (PET) images using an image-derived input function obtained from a manually drawn carotid artery region. Here, we investigate the use of independent component analysis (ICA) for more objective identification of the carotid artery and surrounding tissue regions. Using FDG PET data from 22 subjects, ICA was applied to an easily defined cubical region including the carotid artery and neighboring tissue. Carotid artery and tissue time activity curves and three venous samples were used to generate spillover and partial volume-corrected input functions and to calculate the parametric images of the cerebral metabolic rate for glucose (CMRgl). Different from a blood-sampling-free ICA approach, the results from our ICA approach are numerically well matched to those based on the arterial blood sampled input function. In fact, the ICA-derived input functions and CMRgl measurements were not only highly correlated (correlation coefficients >0.99) to, but also highly comparable (regression slopes between 0.92 and 1.09), with those generated using arterial blood sampling. Moreover, the reliability of the ICA-derived input function remained high despite variations in the location and size of the cubical region. The ICA procedure makes it possible to quantify FDG PET images in an objective and reproducible manner. Image-derived input function by ICA for FDG-PET.

  4. SOD1 Overexpression Preserves Baroreflex Control of Heart Rate with an Increase of Aortic Depressor Nerve Function.

    PubMed

    Hatcher, Jeffrey; Gu, He; Cheng, Zixi Jack

    2016-01-01

    Overproduction of reactive oxygen species (ROS), such as the superoxide radical (O2 (∙-)), is associated with diseases which compromise cardiac autonomic function. Overexpression of SOD1 may offer protection against ROS damage to the cardiac autonomic nervous system, but reductions of O2 (∙-) may interfere with normal cellular functions. We have selected the C57B6SJL-Tg (SOD1)2 Gur/J mouse as a model to determine whether SOD1 overexpression alters cardiac autonomic function, as measured by baroreflex sensitivity (BRS) and aortic depressor nerve (ADN) recordings, as well as evaluation of baseline heart rate (HR) and mean arterial pressure (MAP). Under isoflurane anesthesia, C57 wild-type and SOD1 mice were catheterized with an arterial pressure transducer and measurements of HR and MAP were taken. After establishing a baseline, hypotension and hypertension were induced by injection of sodium nitroprusside (SNP) and phenylephrine (PE), respectively, and ΔHR versus ΔMAP were recorded as a measure of baroreflex sensitivity (BRS). SNP and PE treatment were administered sequentially after a recovery period to measure arterial baroreceptor activation by recording aortic depressor nerve activity. Our findings show that overexpression of SOD1 in C57B6SJL-Tg (SOD1)2 Gur/J mouse preserved the normal HR, MAP, and BRS but enhanced aortic depressor nerve function. PMID:26823951

  5. SOD1 Overexpression Preserves Baroreflex Control of Heart Rate with an Increase of Aortic Depressor Nerve Function

    PubMed Central

    Hatcher, Jeffrey; Gu, He; Cheng, Zixi (Jack)

    2016-01-01

    Overproduction of reactive oxygen species (ROS), such as the superoxide radical (O2∙−), is associated with diseases which compromise cardiac autonomic function. Overexpression of SOD1 may offer protection against ROS damage to the cardiac autonomic nervous system, but reductions of O2∙− may interfere with normal cellular functions. We have selected the C57B6SJL-Tg (SOD1)2 Gur/J mouse as a model to determine whether SOD1 overexpression alters cardiac autonomic function, as measured by baroreflex sensitivity (BRS) and aortic depressor nerve (ADN) recordings, as well as evaluation of baseline heart rate (HR) and mean arterial pressure (MAP). Under isoflurane anesthesia, C57 wild-type and SOD1 mice were catheterized with an arterial pressure transducer and measurements of HR and MAP were taken. After establishing a baseline, hypotension and hypertension were induced by injection of sodium nitroprusside (SNP) and phenylephrine (PE), respectively, and ΔHR versus ΔMAP were recorded as a measure of baroreflex sensitivity (BRS). SNP and PE treatment were administered sequentially after a recovery period to measure arterial baroreceptor activation by recording aortic depressor nerve activity. Our findings show that overexpression of SOD1 in C57B6SJL-Tg (SOD1)2 Gur/J mouse preserved the normal HR, MAP, and BRS but enhanced aortic depressor nerve function. PMID:26823951

  6. Noise Reduction in Arterial Spin Labeling Based Functional Connectivity Using Nuisance Variables.

    PubMed

    Jann, Kay; Smith, Robert X; Rios Piedra, Edgar A; Dapretto, Mirella; Wang, Danny J J

    2016-01-01

    Arterial Spin Labeling (ASL) perfusion image series have recently been utilized for functional connectivity (FC) analysis in healthy volunteers and children with autism spectrum disorders (ASD). Noise reduction by using nuisance variables has been shown to be necessary to minimize potential confounding effects of head motion and physiological signals on BOLD based FC analysis. The purpose of the present study is to systematically evaluate the effectiveness of different noise reduction strategies (NRS) using nuisance variables to improve perfusion based FC analysis in two cohorts of healthy adults using state of the art 3D background-suppressed (BS) GRASE pseudo-continuous ASL (pCASL) and dual-echo 2D-EPI pCASL sequences. Five different NRS were performed in healthy volunteers to compare their performance. We then compared seed-based FC analysis using 3D BS GRASE pCASL in a cohort of 12 children with ASD (3f/9m, age 12.8 ± 1.3 years) and 13 typically developing (TD) children (1f/12m; age 13.9 ± 3 years) in conjunction with NRS. Regression of different combinations of nuisance variables affected FC analysis from a seed in the posterior cingulate cortex (PCC) to other areas of the default mode network (DMN) in both BOLD and pCASL data sets. Consistent with existing literature on BOLD-FC, we observed improved spatial specificity after physiological noise reduction and improved long-range connectivity using head movement related regressors. Furthermore, 3D BS GRASE pCASL shows much higher temporal SNR compared to dual-echo 2D-EPI pCASL and similar effects of noise reduction as those observed for BOLD. Seed-based FC analysis using 3D BS GRASE pCASL in children with ASD and TD children showed that noise reduction including physiological and motion related signals as nuisance variables is crucial for identifying altered long-range connectivity from PCC to frontal brain areas associated with ASD. This is the first study that systematically evaluated the effects of

  7. Noise Reduction in Arterial Spin Labeling Based Functional Connectivity Using Nuisance Variables

    PubMed Central

    Jann, Kay; Smith, Robert X.; Rios Piedra, Edgar A.; Dapretto, Mirella; Wang, Danny J. J.

    2016-01-01

    Arterial Spin Labeling (ASL) perfusion image series have recently been utilized for functional connectivity (FC) analysis in healthy volunteers and children with autism spectrum disorders (ASD). Noise reduction by using nuisance variables has been shown to be necessary to minimize potential confounding effects of head motion and physiological signals on BOLD based FC analysis. The purpose of the present study is to systematically evaluate the effectiveness of different noise reduction strategies (NRS) using nuisance variables to improve perfusion based FC analysis in two cohorts of healthy adults using state of the art 3D background-suppressed (BS) GRASE pseudo-continuous ASL (pCASL) and dual-echo 2D-EPI pCASL sequences. Five different NRS were performed in healthy volunteers to compare their performance. We then compared seed-based FC analysis using 3D BS GRASE pCASL in a cohort of 12 children with ASD (3f/9m, age 12.8 ± 1.3 years) and 13 typically developing (TD) children (1f/12m; age 13.9 ± 3 years) in conjunction with NRS. Regression of different combinations of nuisance variables affected FC analysis from a seed in the posterior cingulate cortex (PCC) to other areas of the default mode network (DMN) in both BOLD and pCASL data sets. Consistent with existing literature on BOLD-FC, we observed improved spatial specificity after physiological noise reduction and improved long-range connectivity using head movement related regressors. Furthermore, 3D BS GRASE pCASL shows much higher temporal SNR compared to dual-echo 2D-EPI pCASL and similar effects of noise reduction as those observed for BOLD. Seed-based FC analysis using 3D BS GRASE pCASL in children with ASD and TD children showed that noise reduction including physiological and motion related signals as nuisance variables is crucial for identifying altered long-range connectivity from PCC to frontal brain areas associated with ASD. This is the first study that systematically evaluated the effects of

  8. Impact of age on the vasodilatory function of human skeletal muscle feed arteries.

    PubMed

    Park, Song-Young; Ives, Stephen J; Gifford, Jayson R; Andtbacka, Robert H I; Hyngstrom, John R; Reese, Van; Layec, Gwenael; Bharath, Leena P; Symons, John D; Richardson, Russell S

    2016-01-15

    Although advancing age is often associated with attenuated skeletal muscle blood flow and skeletal muscle feed arteries (SMFAs) have been recognized to play a regulatory role in the vasculature, little is known about the impact of age on the vasodilatory capacity of human SMFAs. Therefore, endothelium-dependent and -independent vasodilation were assessed in SMFAs (diameter: 544 ± 63 μm) obtained from 24 (equally represented) young (33 ± 2 yr) and old (71 ± 2 yr) subjects in response to three stimuli: 1) flow-induced shear stress, 2) ACh, and 3) sodium nitropusside (SNP). Both assessments of endothelium-dependent vasodilation, flow (young subjects: 68 ± 1% and old subjects: 32 ± 7%) and ACh (young subjects: 92 ± 3% and old subjects: 73 ± 4%), were significantly blunted (P < 0.05) in SMFAs of old compared with young subjects, with no such age-related differences in endothelium-independent vasodilation (SNP). In response to an increase in flow-induced shear stress, vasodilation kinetics (time constant to reach 63% of the amplitude of the response: 55 ± 1 s in young subjects and 92 ± 7 s in old subjects) and endothelial nitric oxide synthase (eNOS) activation (phospho-eNOS(s1177)/total eNOS: 1.0 ± 0.1 in young subjects and 0.2 ± 0.1 in old subjects) were also significantly attenuated in old compared with young subjects (P < 0.05). Furthermore, the vessel superoxide concentration was greater in old subjects (old subjects: 3.9 ± 1.0 area under curve/mg and young subjects: 1.7 ± 0.1 area under the curve/mg, P < 0.05). These findings reveal that the endothelium-dependent vasodilatory capacity, including vasodilation kinetics but not smooth muscle function, of human SMFAs is blunted with age and may be due to free radicals. Given the potential regulatory role of SMFAs in skeletal muscle blood flow, these findings may explain, at least in part, the often observed attenuated perfusion of skeletal muscle with advancing age that may contribute to exercise

  9. The relation of arterial stiffness to endothelial function in healthy subjects.

    PubMed

    Wright, C I; Brouwer-de Cock, K A J; Kroner, C I; Hoeks, A P G; Draijer, R

    2007-05-01

    Local wall stiffness affects endothelial responsiveness but how global measures affect responsiveness is unanswered. We assessed this by comparing reactive hyperaemic responses of brachial diameter (RHRBD) with central (heart-to-brachial artery pulse wave velocity (PWV); large (C1)) and peripheral (C2) arterial stiffness. Twelve healthy subjects were investigated. RHRBD was induced via an upper- or forearm occluding cuff. Arterial diameter changes were measured using echo ultrasound. Arterial stiffness and RHRBD were compared using a Pearson correlation coefficient (r) and Bland-Altman analysis of Z-scores (indicated as 95% confidence intervals (CI) and expressed in units of standard deviation (SD) from the mean). Weak relations were found between upper-arm RHRBD responses and C2 (r = 0.56, P = 0.06; 95% CI +/- 1.84 SDs) and C1 (r = 0.55, P = 0.06; 95% CI +/- 1.86 SDs). An inverse relation was found between upper-arm RHRBD responses and PWV (r = -0.55, P = 0.06), but Bland-Altman plots revealed no agreement between these parameters (P > 0.05; 95% CI +/- 3.46 SDs). Forearm RHRBD were not related to PWV, C1 or C2 (P > 0.05; 95% CI > 2 SDs). The weak relation between upper-arm endothelial responses and C2 and C1 seems to suggest that C2, and also C1, is not a good and reliable method for assessments of endothelial health. Furthermore, if anything, upper-arm mediated RHRBD responses are more affected by arterial stiffness than forearm responses. PMID:17470989

  10. Exercise reduces GABA synaptic input onto NTS baroreceptor second-order neurons via NK1 receptor internalization in spontaneously hypertensive rats

    PubMed Central

    Chen, Chao-Yin; Bechtold, Andrea G.; Tabor, Jocelyn; Bonham, Ann C.

    2009-01-01

    A single bout of mild to moderate exercise can lead to a post-exercise decrease in blood pressure in hypertensive subjects, namely post-exercise hypotension (PEH). The full expression of PEH requires a functioning baroreflex, hypertension and activation of muscle afferents (exercise), suggesting that interactions in the neural networks regulating exercise and blood pressure result in this fall in blood pressure. The nucleus tractus solitarii (NTS) is the first brain site that receives inputs from nerves carrying blood pressure and muscle activity information, making it an ideal site for integrating cardiovascular responses to exercise. During exercise, muscle afferents excite NTS GABA neurons via substance P and microinjection of a substance P-neurokinin 1 receptor (NK1-R) antagonist into the NTS attenuates PEH. The data suggest that an interaction between the substance P NK1-R and GABAergic transmission in the NTS may contribute to PEH. We performed voltage-clamping on NTS baroreceptor second-order neurons in spontaneously hypertensive rats (SHRs). All animals were sacrificed within 30 min and the patch-clamp recordings were performed 2-8 hr after the sham/exercise protocol. The data showed that a single bout of exercise reduces 1) the frequency but not the amplitude of GABA spontaneous inhibitory synaptic currents (sIPCs), 2) endogenous substance P influence on sIPSC frequency, and 3) sIPSC frequency response to exogenous application of substance P. Furthermore, immunofluorescence labeling in NTS show an increased substance P NK1-R internalization on GABA neurons. The data suggest that exercise-induced NK1-R internalization results in a reduced intrinsic inhibitory input to the neurons in the baroreflex pathway. PMID:19261870