Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eleven resting patients with an implanted DDD pacemaker were studied. After 30 minutes of AV sequential pacing at a rate of 80 beats/min with three consecutive atrioventricular delays (AVDs; 100, 150, and 200 msec) peripheral venous blood was drawn for further analyses by specific radioimmunoassays of atrial natriuretic peptide (ANP) and the ANP second messenger, cyclic guanosine monophosphate (cGMP). Relative changes in left ventricular (LV) stroke volume following alterations of AVD were assessed by means of pulsed-Doppler echocardiography through measurement of LV outflow time-velocity integrals (TVI). The optimal AVD (oAVD) was defined in individual patients as that which was associated with the greatest TVI and with improvement over both other AVDs of more than 4%. The oAVD was found in nine patients. For these nine patients no significant differences in either plasma ANP or cGMP between various AVDs were observed. However, we found such differences with respect to values measured at oAVD; both ANP and cGMP levels were lowest at oAVD. Pooling together the data obtained in 11 patients at three AVDs, a positive correlation between ANP and cGMP levels was found (r = 0.7, P < 0.0001, n = 33). Moreover, changes of plasma ANP and cGMP induced by every AVD increment of 50 msec were also correlated (r = 0.6, P < 0.01, n = 22). It is concluded that in AV sequential pacing at rest plasma ANP reaches minimal levels at the AVD, which provides the best LV performance. Although levels of cGMP changed in parallel with those of ANP, low relative values of cGMP differences may limit the usefulness of cGMP assays in optimization of the AVD.
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PMID:Plasma ANP and cyclic GMP levels versus left ventricular performance at different AV delays in AV sequential pacing. 751 46

The aim of the present study was to determine whether the level of plasma atrial natriuretic peptide (ANP), an indicator of atrial stretching, correlates with the formation of a thrombus in the left atrium during cardioembolic stroke with atrial fibrillation. Plasma concentrations of immunoreactive ANP and thrombin-antithrombin III complex (TAT) were measured in five age-matched groups including: 16 patients with acute cardioembolic stroke and atrial fibrillation (group 1), 26 patients with chronic cardioembolic stroke and atrial fibrillation (group 2), 27 patients with atrial fibrillation without previous stroke (group 3), 21 patients with acute lacunar stroke (group 4), and 27 healthy controls. The plasma ANP levels were higher in group 1, regardless of the stage, than those estimated at chronic stage in group 4 and in healthy controls. There were no stage-related differences between groups 1, 2 and 3. Plasma levels of ANP in group 2, a high risk group of cardioembolic stroke, were higher than in group 3, a low risk group. There was no correlation between plasma levels of ANP and mean blood pressure, pulse rate or plasma levels of TAT in any group. These results indicate that the determination of plasma ANP concentration is useful to distinguish a high risk patient from a low risk patient and also a cardioembolic stroke patient from a lacunar stroke patient. They also underscore the difficulties in recognizing left atrial thrombus formation by determining the plasma ANP concentration in cardioembolic stroke.
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PMID:Plasma concentrations of atrial natriuretic peptide in cardioembolic stroke with atrial fibrillation. 756 67

The plasma levels of endothelin-1 (ET-1) and atrial natriuretic peptide (ANP) have been measured in 37 patients with acute ischemic stroke, on admission and 3 and 7 days thereafter. The plasma ET-1 levels at the onset of symptoms were about two-fold those observed in age-matched normal volunteers (3.5 +/- 2.26 v 1.54 +/- 0.9 pg/mL, respectively; P < .001). These levels remained significantly elevated during the 7-day study period. The neurologic deficit was assessed daily by Mathew's modified scale (MS). A significant correlation was found between neurologic status on admission and ET-1 plasma values; patients with worse neurologic status (MS < 45 points) had higher ET-1 plasma values than those with better neurologic status (MS > 45 points) (5.4 +/- 2.34 v 3.05 +/- 2.04 pg/mL, respectively, P < .05). The plasma ET-1 values did not correlate either with the site of the infarction or with its primary cause (cardioembolic, lacunar, or atherothrombotic). No significant differences were seen in plasma ET-1 concentrations between patients who eventually died and those who survived the acute event. The plasma ANP were about 18-fold higher in ischemic stroke patients on admission than in controls at admission (110.9 +/- 29.5 v 5.84 +/- 3.96 pg/mL, respectively, P < .01). These values remained significantly elevated on days 3 and 7. There was no correlation between the ANP plasma values and the neurologic status, the site or mechanism of the stroke, or the plasma ET-1 levels. In conclusion, ischemic stroke is associated with marked acute and long-duration increases of ET-1 and ANP.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:High plasma levels of endothelin-1 and atrial natriuretic peptide in patients with acute ischemic stroke. 770 3

We compared plasma atrial natriuretic peptide (ANP) and cGMP levels during normal pregnancy--a condition characterized by hypervolemia, high cardiac output, and decreased vascular resistance--with postpartum levels and assessed their relation to pregnancy-induced hemodynamic changes. Humoral and hemodynamic variables were measured in healthy women subjects in the supine and upright postures at each trimester of pregnancy and postpartum. Supine plasma ANP was increased throughout pregnancy (32 +/- 5, 21 +/- 3, and 19 +/- 2 versus 15 +/- 1 pmol.L-1, respectively, at each trimester versus postpartum), as was cGMP (8.6 +/- 1, 7.1 +/- 1, and 6.6 +/- 1 versus 5.6 +/- 1 nmol.L-1), and their increments were directly related (r = .68, P < .01). Both ANP and cGMP levels did not differ from postpartum levels after subjects stood. Supine stroke volume was initially increased but declined below postpartum levels in late pregnancy (69 +/- 4, 60 +/- 3, and 44 +/- 3 versus 58 +/- 4 mL.m-2), whereas after subjects stood it was always higher (56 +/- 3, 58 +/- 3, and 49 +/- 2 versus 44 +/- 2 mL.m-2); thus, stroke volume tended to increase in response to standing in late pregnancy. Supine cardiac index had a similar trend, which was opposite to that of total peripheral resistance (1213 +/- 62, 1265 +/- 79, and 1729 +/- 89 versus 1654 +/- 92 dyne.s-1.cm-5.m-2).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Atrial natriuretic peptide and hemodynamic changes during normal human pregnancy. 772 8

Head-down tilt (HDT) bed rest was used in this study to achieve physiological manipulation of the plasma concentrations of atrial natriuretic peptide (ANP) and the hormones of the renin-angiotensin system. The purpose of this was to achieve a parallel with previous animal experiments in which blockade of the renin-angiotensin system caused significant increases in low-frequency spectral power of heart rate variability, presumably as a consequence of increased blood pressure variability, although this was not measured in these animal experiments. Eight healthy young men completed 10 h of seated control and 6 degrees HDT. To gain a more complete understanding of the interactions between hormonal and neural factors involved in cardiovascular regulation, we measured heart rate, systolic and diastolic pressure variabilities, plasma hormone concentrations, and blood flow to selected vascular beds by pulsed Doppler. Resting R-R interval was not significantly different between seated and HDT tests. Stroke volume and cardiac output were elevated in the first 1-2 h of HDT (P < 0.05), whereas each of systolic (P < 0.01) and diastolic (P < 0.0001) pressures was lower during HDT. Plasma ANP increased as much as 70% during HDT (P < 0.0001). Total variability in each of R-R interval and diastolic blood pressure was reduced during HDT (P < 0.001). Thus, at a time when plasma renin activity was decreased as much as 40% (P < 0.0001), there was in fact a decrease in the variability of R-R interval and diastolic blood pressure in contrast to the hypothesized increase such as found in previous animal experimentation. The data were compatible with tighter autonomic regulation of heart rate about the ideal mean value during HDT.
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PMID:Investigation of hormonal effects during 10-h head-down tilt on heart rate and blood pressure variability. 775 28

To investigate the mechanism by which an increase in pacing frequency or distension increases the secretion of atrial natriuretic peptide (ANP), the changes in atrial volume during contraction (atrial stroke volume), transmural transport of the extracellular fluid (ECF), and ANP secretion were quantified in the beating perfused rabbit atria. The atrium was stimulated by transmural field stimulation or by atrial distension induced by an increase in intraatrial pressure. Atrial stretch and incremental increases in pacing frequency up to 2 Hz activated the secretion of ANP coincident with an increase in atrial stroke volume and the transendocardial translocation of the ECF. These results showed positive relationships between changes in the secretion of ANP and the atrial stroke volume or the translocation of the ECF. The translocation of the ECF was also positively correlated with the change in atrial stroke volume. The accentuated secretion of ANP and translocation of the ECF waned at higher stimulating rates to show a peak value. Even under this condition, the secretion of ANP was a function of the translocation of the ECF. These data suggest that the increases in atrial stroke volume and translocation of ECF are fundamental factors in the ANP stimulation in response to atrial stretch and increases in atrial rate.
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PMID:Mechanical basis of ANP secretion in beating atria: atrial stroke volume and ECF translocation. 777 72

The effects of 150 ng/kg iv injections of arginine vasotocin (AVT), eel atrial natriuretic peptide (ANP), and epinephrine (Epi) on the cardiovascular dynamics of resting freshwater eels, Anguilla rostrata were studied. Injection of AVT into the caudal vein significantly increased cardiac output (CO) from 15.3 to 23.6 ml.min-1.kg-1 primarily by increasing stroke volume. Mean dorsal aortic pressure (PDA) also increased. Estimated branchial shunting (2.54 ml.min-1.kg-1) was elevated by 130% because of an increased proportion of CO, indicating a vasoconstriction of the branchial arterioarterial pathway. In contrast, Epi reduced the fraction of CO perfusing the arteriovenous pathway. Epi also produced a positive chronotropic effect, increased CO and systemic vasoconstriction, resulting in a vasopressor response. These changes occurred earlier than those of AVT and ANP. Pressor responses triggered by AVT and Epi preceded the increases in CO. Injections of 150 and 200 ng/kg ANP caused a reduction in PDA due to a decrease in CO (and SV) but failed to modulate systemic resistance. The change in CO was the primary contributor to the pressor (and depressor) responses elicited by the three hormones.
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PMID:Cardiovascular effects of arginine vasotocin, atrial natriuretic peptide, and epinephrine in freshwater eels. 777 90

The purpose was to determine whether extracellular volume or osmolality was the major contributing factor for reduction of thirst in air and head-out water immersion in hypohydrated subjects. Eight males (19-25 yr) were subjected to thermoneutral immersion and thermoneutral air under two hydration conditions without further drinking: euhydration in water (Eu-H2O) and euhydration in air, and hypohydration in water (Hypo-H2O) and hypohydration in air (3.7% wt loss after exercise in heat). The increased thirst sensation with Hypo-H2O decreased (P < 0.05) within 10 min of immersion and continued thereafter. Mean plasma osmolality (288 +/- 1 mosmol/kgH2O) and sodium (140 +/- 1 meq/l) remained elevated, and plasma volume increased by 4.2 +/- 1.0% (P < 0.05) throughout Hypo-H2O. A sustained increase (P < 0.05) in stroke volume accompanied the prompt and sustained decrease in plasma renin activity and sustained increase (P < 0.05) in plasma atrial natriuretic peptide during Eu-H2O and Hypo-H2O. Plasma vasopressin decreased from 5.3 +/- 0.7 to 2.9 +/- 0.5 pg/ml (P < 0.05) during Hypo-H2O but was unchanged in Eu-H2O. These findings suggest a sustained stimulation of the atrial baroreceptors and reduction of a dipsogenic stimulus without major alterations of extracellular osmolality in Hypo-H2O. Thus it appears that vascular volume-induced stimuli of cardiopulmonary baroreceptors play a more important role than extracellular osmolality in reducing thirst sensations during immersion in hypohydrated subjects.
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PMID:Mechanism of thirst attenuation during head-out water immersion in men. 790 Aug 99

Diurnal variation has been demonstrated for blood pressure and heart function. Several hormones influence these hemodynamic parameters. This study investigates the diurnal variation in plasma prorenin in relation to renin, atrial natriuretic peptide (ANP), norepinephrine, and hemodynamic changes. Circulating plasma prorenin may be able to serve as a marker for the activity of the local renin-angiotensin system. In 12 healthy male volunteers who were allowed to carry out quiet activity, hemodynamic factors and the plasma levels of hormones were monitored at 2-h intervals for 26 h. Blood pressure was measured every hour. In accordance with the literature, during the night blood pressure (4%), cardiac index (19%), stroke index (10%), and heart rate (10%) decreased in a classic day-night pattern. Systemic vascular resistance increased during the night (23%). No classic day-night pattern was found for ANP, although it increased (15%) at night and showed a peak early in the night. This peak seemed to be influenced by posture. A classic day-night pattern was demonstrated for norepinephrine and prorenin. Norepinephrine was lower (18%) at night and increased as soon as the subjects awoke, while they were still in bed. Therefore, plasma norepinephrine levels seemed to be related to awakening. Plasma prorenin decreased at night (6%). Renin fluctuated throughout the day, but showed no clear day-night pattern. In conclusion, renin fluctuated throughout the day and did not show a classic day-night pattern. In contrast, prorenin fluctuated less and showed 6% higher levels during the day compared to the night. The origin and clinical significance of this small diurnal variation in prorenin is not clear yet.
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PMID:Diurnal variation in prorenin in relation to other humoral factors and hemodynamics. 798 63

The systemic and pulmonary haemodynamic effects of i.v. infusion (1 ml/s) of high doses (4 ml/kg) of 2 non-ionic, isoosmolar dimeric contrast media (CM) were investigated in 17 female pigs. The 2 CM were iodixanol and iotrolan. Both CM induced a significant increase of the following parameters: mean arterial, mean right atrial, mean pulmonary arterial, mean pulmonary arterial occlusion pressure, cardiac output, stroke volume, and diuresis. The plasma concentration of atrial natriuretic peptide was significantly increased following infusion of the 2 CM. A significant decrease was seen in the systemic and pulmonary vascular resistance.
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PMID:Systemic and pulmonary haemodynamic effects of intravenous infusion of non-ionic isoosmolar dimeric contrast media. An investigation in the pig of two ratio 6 contrast media. 801 90


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