LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 4 of total 4

Search options

  1. Article ; Online: L-arginine augments cardiac vagal control in healthy human subjects.

    Chowdhary, Saqib / Nuttall, Sarah L / Coote, John H / Townend, Jonathan N

    Hypertension (Dallas, Tex. : 1979)

    2002  Volume 39, Issue 1, Page(s) 51–56

    Abstract: Cardiac vagal control has prognostic significance in cardiac disease, but the control mechanisms of this system remain poorly understood. We have previously demonstrated a role for NO in promoting vagal control of heart rate in humans. Here we examine ... ...

    Abstract Cardiac vagal control has prognostic significance in cardiac disease, but the control mechanisms of this system remain poorly understood. We have previously demonstrated a role for NO in promoting vagal control of heart rate in humans. Here we examine the influence of L-arginine, the substrate for NO synthase, on this mechanism in healthy human subjects. Eleven healthy volunteers (9 men; age, 20 to 25 years) underwent measurement of heart rate variability and baroreflex sensitivity before and during a systemic infusion of L-arginine (1 g/min; total, 30 g). To control for the fall in blood pressure, comparison was made with an infusion of the control vasodilator hydralazine. Stereospecificity of observed effects was investigated by infusion of D-arginine. Urinary nitrate and nitrite (NO(x)) and cGMP concentrations were measured as indexes of NO generation. L-Arginine infusion produced a drop in mean arterial pressure of 5 mm Hg. This fall in blood pressure was matched by hydralazine infusion and was not observed with either D-arginine or saline infusion. Although RR interval duration, heart rate variability, and baroreflex sensitivity all fell significantly with hydralazine, the same degree of baroreflex unloading with L-arginine produced an increase in RR interval duration and no change or even slight increases in heart rate variability and baroreflex sensitivity. In contrast, D-arginine produced falls in high-frequency indexes of heart rate variability compared with saline. Only L-arginine increased urinary NO(x) and cGMP excretion. In conclusion, these data demonstrate that short-term L-arginine infusion facilitates vagal control of heart rate in healthy humans, probably via increased NO synthesis.
    MeSH term(s) Adult ; Arginine/pharmacology ; Baroreflex/drug effects ; Baroreflex/physiology ; Blood Pressure/drug effects ; Cross-Over Studies ; Female ; Heart/drug effects ; Heart/physiology ; Heart Rate/drug effects ; Heart Rate/physiology ; Humans ; Hydralazine/pharmacology ; Male ; Nitric Oxide/metabolism ; Nitric Oxide/physiology ; Single-Blind Method ; Stereoisomerism ; Vagus Nerve/drug effects ; Vagus Nerve/physiology ; Vasodilator Agents/pharmacology
    Chemical Substances Vasodilator Agents ; Hydralazine (26NAK24LS8) ; Nitric Oxide (31C4KY9ESH) ; Arginine (94ZLA3W45F)
    Language English
    Publishing date 2002-01
    Publishing country United States
    Document type Clinical Trial ; Journal Article ; Randomized Controlled Trial ; Research Support, Non-U.S. Gov't
    ZDB-ID 423736-5
    ISSN 1524-4563 ; 0194-911X ; 0362-4323
    ISSN (online) 1524-4563
    ISSN 0194-911X ; 0362-4323
    DOI 10.1161/hy0102.098308
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 1488: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  2. Article: Vitamin C improves resistance but not conduit artery endothelial function in patients with chronic renal failure.

    Cross, Jenny M / Donald, Ann E / Nuttall, Sarah L / Deanfield, John E / Woolfson, Robin G / Macallister, Raymond J

    Kidney international

    2003  Volume 63, Issue 4, Page(s) 1433–1442

    Abstract: Background: Chronic renal failure is associated with impaired endothelium-dependent vasodilation and accelerated atherogenesis. To examine whether endogenous reactive oxygen species (ROS) modify endothelial function in renal failure, we evaluated the ... ...

    Abstract Background: Chronic renal failure is associated with impaired endothelium-dependent vasodilation and accelerated atherogenesis. To examine whether endogenous reactive oxygen species (ROS) modify endothelial function in renal failure, we evaluated the effect of the antioxidant vitamin C on endothelium-dependent responses in both the conduit and resistance vasculature of subjects with severe renal impairment.
    Methods: Endothelial function of the forearm resistance vasculature was assessed using plethysmography to measure the dilator response to intra-arterial acetylcholine (Ach) (25 to 100 nmol/min). Endothelial function of radial and brachial arteries was assessed using vascular ultrasound to measure the dilator response to flow during reactive hyperemia [flow-mediated dilatation (FMD)]. Studies were performed before and after administration of vitamin C by intra-arterial infusion (25 mg/min) in 33 predialysis patients or by intravenous infusion (3 g) in 17 hemodialysis patients.
    Results: Parenteral administration of vitamin C resulted in a 100-fold increase (intra-arterial studies) and a 4.5-fold increase (intravenous studies) in serum antioxidant activity. Vitamin C administration increased the dilator response to ACh in resistance vessels (P = 0.01), but did not alter the dilator response to flow in conduit vessels of either dialysis (P = 0.3) or predialysis subjects (P = 0.8). In the presence of the nitric oxide (NO) synthase inhibitor NGmonomethyl-L-arginine (L-NMMA), there was no effect of vitamin C on resistance vessel endothelial function. In all cases the dilator response to the endothelium-independent dilators was unaffected by vitamin C.
    Conclusion: Acute administration of vitamin C reduces oxidant stress in renal failure and improves NO-mediated resistance vessel dilatation.
    MeSH term(s) Adult ; Antioxidants/administration & dosage ; Ascorbic Acid/administration & dosage ; Biomarkers ; Brachial Artery/physiology ; Endothelium, Vascular/drug effects ; Endothelium, Vascular/physiology ; Female ; Humans ; Kidney Failure, Chronic/drug therapy ; Kidney Failure, Chronic/physiopathology ; Male ; Middle Aged ; Nitric Oxide/metabolism ; Oxidative Stress/drug effects ; Radial Artery/physiology ; Renal Dialysis ; Vascular Resistance/drug effects ; Vasodilation/drug effects
    Chemical Substances Antioxidants ; Biomarkers ; Nitric Oxide (31C4KY9ESH) ; Ascorbic Acid (PQ6CK8PD0R)
    Language English
    Publishing date 2003-04
    Publishing country United States
    Document type Clinical Trial ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 120573-0
    ISSN 1523-1755 ; 0085-2538
    ISSN (online) 1523-1755
    ISSN 0085-2538
    DOI 10.1046/j.1523-1755.2003.00852.x
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 797: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  3. Article: Anti-oxidative properties of beta-blockers and angiotensin-converting enzyme inhibitors in congestive heart failure.

    Chin, Bernard S P / Langford, Nigel J / Nuttall, Sarah L / Gibbs, Christopher R / Blann, Andrew D / Lip, Gregory Y H

    European journal of heart failure

    2003  Volume 5, Issue 2, Page(s) 171–174

    Abstract: Background: Chronic elevation of plasma catecholamines and sympathetic stimulation in chronic heart failure (CHF) leads to increased production of free radicals, and so possibly to endothelial damage/dysfunction and atheroma formation. Abnormal ... ...

    Abstract Background: Chronic elevation of plasma catecholamines and sympathetic stimulation in chronic heart failure (CHF) leads to increased production of free radicals, and so possibly to endothelial damage/dysfunction and atheroma formation. Abnormal oxidative stress may therefore be related to some of the high mortality and morbidity in CHF. The objective of the present prospective open study was to compare the effects of beta-blockers and ACE inhibitors in relation to oxidative stress and endothelial damage in CHF.
    Methods: We studied 66 outpatients with CHF: 46 patients were established on an ACE inhibitor and were then started on a beta-blocker, and 20 patients not previously on ACE-inhibitors were started on lisinopril. Baseline levels of the measured parameters were compared to 22 healthy control subjects. Serum lipid hydroperoxides (LHP) and total antioxidant capacity (TAC) were determined as indices of oxidative damage and antioxidant defence, and plasma von Willebrand factor (vWf) as an index of endothelial damage/dysfunction.
    Results: Baseline indices for the measures of oxidative damage and endothelial function in the 66 CHF patients were significantly higher than healthy control subjects [median LHP 7.5 (5.9-12.6) vs. 4.8 micromol/l, P=0.0022; TAC 428 (365-567) vs. 336 Trollox Eq. Units, P=0.0005; mean vWf 134+/-27 vs. 89+/-23 IU/dl, P<0.0001]. Following 3 months of maintenance therapy with beta-blockers, there was significant reduction in LHP levels, but not TAC or vWf. ACE inhibitor therapy also significantly reduced vWf levels, but failed to have any statistically significant effects on LHP or TAC.
    Conclusion: This pilot study suggests that oxidative stress in CHF may be due to increased free radical production or inefficient free radical clearance by scavengers. beta-Blockers, but not ACE inhibitors, reduced lipid peroxidation in patients with CHF. No relation was demonstrated between a reduction in oxidative damage and endothelial damage/dysfunction.
    MeSH term(s) Adrenergic beta-Antagonists/therapeutic use ; Aged ; Angiotensin-Converting Enzyme Inhibitors/therapeutic use ; Biomarkers/blood ; Bisoprolol/therapeutic use ; Blood Pressure/drug effects ; Carbazoles/therapeutic use ; Carvedilol ; Endothelium, Vascular/drug effects ; Endothelium, Vascular/metabolism ; Endothelium, Vascular/physiopathology ; Female ; Follow-Up Studies ; Heart Failure/blood ; Heart Failure/drug therapy ; Heart Failure/epidemiology ; Humans ; Lipid Peroxides/blood ; Lisinopril/therapeutic use ; Male ; Middle Aged ; Oxidative Stress/drug effects ; Oxidative Stress/physiology ; Propanolamines/therapeutic use ; Prospective Studies ; Risk Factors ; Treatment Outcome ; von Willebrand Factor/metabolism
    Chemical Substances Adrenergic beta-Antagonists ; Angiotensin-Converting Enzyme Inhibitors ; Biomarkers ; Carbazoles ; Lipid Peroxides ; Propanolamines ; von Willebrand Factor ; Carvedilol (0K47UL67F2) ; Lisinopril (E7199S1YWR) ; Bisoprolol (Y41JS2NL6U)
    Language English
    Publishing date 2003-03
    Publishing country England
    Document type Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1483672-5
    ISSN 1879-0844 ; 1388-9842
    ISSN (online) 1879-0844
    ISSN 1388-9842
    DOI 10.1016/s1388-9842(02)00251-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

    Full text online

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Zs.A 5299: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

  4. Article: Nitric oxide and cardiac parasympathetic control in human heart failure.

    Chowdhary, Saqib / Ng, G Andre / Nuttall, Sarah L / Coote, John H / Ross, Hamish F / Townend, Jonathan N

    Clinical science (London, England : 1979)

    2002  Volume 102, Issue 4, Page(s) 397–402

    Abstract: Cardiac parasympathetic control has prognostic significance in heart failure, but the control mechanisms of this system remain poorly defined. We have demonstrated previously a facilitatory role for nitric oxide (NO) in the parasympathetic control of ... ...

    Abstract Cardiac parasympathetic control has prognostic significance in heart failure, but the control mechanisms of this system remain poorly defined. We have demonstrated previously a facilitatory role for nitric oxide (NO) in the parasympathetic control of heart rate in young healthy human subjects. In view of the complex abnormalities of regional NO activity observed in chronic heart failure, we now aim to establish if this mechanism is active in subjects with this condition. Groups of 12 heart failure patients [NYHA class II-III; mean age 52 years (range 38-67 years)] and 12 age/sex-matched healthy control subjects [mean age 50 years (range 36-62 years)] were studied. Heart rate variability and baroreflex sensitivity were measured during inhibition of endogenous NO production with N(G)-monomethyl-l-arginine (l-NMMA; 3 mg.h(-1).kg(-1)) and during administration of an equipressor dose of the control vasoconstrictor phenylephrine (12-36 microg.h(-1).kg(-1)). Basal levels of nitrate+nitrite were measured in the plasma as an indication of systemic NO production. In the heart failure patients, despite an equal rise in blood pressure with both drugs, high-frequency indices of heart rate variability increased less with l-NMMA than with phenylephrine: RMSSD (root mean square of successive RR-interval differences) increased by 4+/-2 compared with 26+/-8 ms (P<0.001) and high-frequency power increased by 97+/-62 compared with 1372+/-861 ms(2) (P<0.001). The increases in cross-spectral baroreflex sensitivity were also lower with l-NMMA than with phenylephrine [high-frequency alpha-index, 2.2+/-1.3 and 12.6+/-3.8 ms/mmHg respectively (P<0.001); low-frequency alpha-index, 1.3+/-0.9 and 4.3+/-1.7 ms/mmHg respectively (P<0.05)]. Healthy subjects showed a similar discrepancy in the response of high-frequency indices of heart rate variability to the two drugs, although baroreflex sensitivity responses were significantly different only for the high-frequency alpha-index. Levels of plasma nitrate+nitrite were significantly higher in the heart failure patients compared with controls. These data demonstrate that baroreflex-mediated cardiac parasympathetic activation in human heart failure, as in health, is dependent upon endogenous NO synthesis.
    MeSH term(s) Adult ; Aged ; Baroreflex/drug effects ; Blood Pressure/drug effects ; Cardiotonic Agents/pharmacology ; Cross-Over Studies ; Enzyme Inhibitors/pharmacology ; Female ; Heart Failure/physiopathology ; Heart Rate/drug effects ; Humans ; Male ; Middle Aged ; Nitrates/pharmacology ; Nitric Oxide/physiology ; Nitric Oxide Synthase/antagonists & inhibitors ; Nitrites/pharmacology ; Parasympathetic Nervous System/physiopathology ; Phenylephrine/pharmacology ; Single-Blind Method ; Vasoconstrictor Agents/pharmacology ; omega-N-Methylarginine/pharmacology
    Chemical Substances Cardiotonic Agents ; Enzyme Inhibitors ; Nitrates ; Nitrites ; Vasoconstrictor Agents ; Phenylephrine (1WS297W6MV) ; omega-N-Methylarginine (27JT06E6GR) ; Nitric Oxide (31C4KY9ESH) ; Nitric Oxide Synthase (EC 1.14.13.39)
    Language English
    Publishing date 2002-04
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 760216-9
    ISSN 0143-5221 ; 0144-9664
    ISSN 0143-5221 ; 0144-9664
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

    In stock of ZB MED Cologne/Königswinter

    Ua VI Zs.220 -Suppl.: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 2021: Bestellungen von Artikeln über das Online-Bestellformular
    ab Jg. 2022: Lesesaal (EG)

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

To top