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

1. Isoprenaline was infused into in utero fetal lambs to examine the effect of this beta-adrenoceptor agonist on left ventricular stroke volume and left ventricular output and test the generally held assumption that the fetal ventricle is markedly limited in its ability to increase ventricular output. 2. Seven in utero lambs (121-133 days of gestation) were instrumented with left ventricular dimension transducers, an ascending aortic electromagnetic flow transducer, a brachiocephalic arterial catheter and electrocardiographic and atrial pacing electrodes. 3. On the day of study, 5-8 days following surgery and 129-137 days of gestation, each lamb received infusions of isoprenaline, via the superior vena cava or left atrium, at rates which ranged from 0.005-0.5 microgram kg-1 min-1. 4. Heart rate and left ventricular stroke volume, output and end-diastolic and end-systolic dimensions were measured under control conditions and during various levels of isoprenaline infusion, with and without controlling heart rate. 5. Analysis of variance was done using the mean cell model. Least-square means and standard errors of the least-square means are reported. F ratios were calculated from type III sums-of-squares; P less than 0.05 was considered significant. 6. The mean heart rate increased with isoprenaline (P less than 0.0001) from a mean control level of 169 +/- 8 to 281 +/- 9 beats min-1 (+/- S.E.M.). 7. Mean left ventricular end-diastolic and end-systolic minor axis dimensions decreased significantly with isoprenaline from 16.7 +/- 0.1 mm (control) to 15.7 +/- 0.2 mm (P less than 0.0004) and from 11.7 +/- 0.1 mm (control) to 10.4 +/- 0.2 mm (P less than 0.0001) respectively. When heart rate was controlled with atrial pacing, mean end-diastolic dimension increased significantly at the higher isoprenaline doses from 14.6 +/- 0.1 mm (control) to 15.3 +/- 0.2 mm (control) (P = 0.0002), while mean end-systolic dimension fell significantly from 10.9 +/- 0.1 to 10.5 +/- 0.1 mm (P less than 0.003). Inasmuch as stroke volume increased, the increase in end-diastolic dimension and the fall in end-systolic dimension indicate an increase in venous return to the left ventricle. 8. During spontaneous rhythm, isoprenaline increased stroke volume from 2.45 +/- 0.06 ml (control) to 2.63 +/- 0.09 ml, not statistically significant. When heart rate was controlled, stroke volume increased with isoprenaline dose from 1.68 +/- 0.06 ml (control) to 2.40 +/- 0.08 ml (P less than 0.0001).(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:The in utero left ventricle of the fetal sheep: the effects of isoprenaline. 208 69

Chronic daily administration of cilazapril (1 X 10 mg/kg/day p.o., from age 4 to 14 weeks) to young spontaneously hypertensive rats (SHR) prevented the development of hypertension. The antihypertensive effect of a single dose of cilazapril persisted greater than 24 h. Discontinuation of long-term treatment resulted in an increase of systolic arterial blood pressure (SAP) to control hypertensive levels within 4 days. Following 10 weeks of drug administration, comparative hemodynamic studies were carried out on age-matched (14 weeks) control SHR and cilazapril-treated SHR. Cilazapril-treated SHR had a significantly lower mean arterial blood pressure (MAP) and total peripheral vascular resistance than did control SHR. The antihypertensive effect of cilazapril was not associated with changes in heart rate (HR). The myocardial performance parameters, cardiac output, and stroke volume, were similar in treated and control SHR, suggesting that the antihypertensive effect of cilazapril following chronic administration to SHR is mainly due to a reduction in peripheral vascular resistance. Vasopressor responses to angiotensin I were significantly lower in cilazapril-treated SHR than in control SHR. By contrast, pressor responses to angiotensin II and a high dose of norepinephrine (1.0 microgram/kg i.v.) were significantly enhanced. Isoproterenol elicited a fall in blood pressure in both groups, the extent of which was dependent upon the magnitude of basal blood pressure levels. Chronic cilazapril treatment resulted in a reduction of heart weight, suggesting that the drug may prevent development of cardiac hypertrophy in SHR. Kidney and adrenal weights were unaffected by the chronic treatment. Specific renin activities (SRA) in tissues of SHR were increased by factors of 20 (plasma) or 2 (kidney and adrenal) following cilazapril administration.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Cilazapril prevents hypertension in spontaneously hypertensive rats. 242 85

Postnatal olfactory learning produces both a conditioned behavioral response and a modified olfactory bulb neural response to the learned odor. The present report describes the role of norepinephrine (NE) on both of these learned responses in neonatal rat pups. Pups received olfactory classical conditioning training from postnatal days (PN) 1-18. Training consisted of 18 trials with an intertrial interval of 24 hr. For the experimental group, a trial consisted of a pairing of unconditioned stimulus (UCS, stroking/tactile stimulation) and the conditioned stimulus (CS, odor). Control groups received either only the CS (Odor only) or only the UCS (Stroke only). Within each training condition, pups were injected with either the NE beta-receptor agonist isoproterenol (1, 20, or 4 mg/kg), the NE beta-receptor antagonist propranolol (10, 20, 40 mg/kg), or saline 30 min prior to training. On day 20, pups received one of the following tests: (1) behavioral conditioned responding, (2) injection with 14C-2-deoxyglucose (2-DG) and exposed to the CS odor, or (3) tested for olfactory bulb mitral/tufted cell single-unit responses to the CS odor. The results indicated that training with either: (1) Odor-Stroke-Saline, (2) Odor-Stroke-Isoproterenol-Propranolol, or (3) Odor only-Isoproterenol (2 mg/kg) was sufficient to produce a learned behavioral odor preference, enhanced uptake of 14C-2-DG in the odor-specific foci within the bulb, and a modified output signal from the bulb as measured by single-cell recordings of mitral/tufted cells. Moreover, propranolol injected prior to Odor-Stroke training blocked the acquisition of both the learned behavior and olfactory bulb responses. Thus, NE is sufficient and may be necessary for the acquisition of both learned olfactory behavior and olfactory bulb responses.
 ...
PMID:Norepinephrine and learning-induced plasticity in infant rat olfactory system. 258 63

The authors studied cardiac performance of 36 patients with dilated cardiomiopathy through cardiac catheterization and left ventriculography in comparison with a control group. It has been verified that the end systolic volume (ESV) is more sensitive than ejection fraction (EF) as an indicator of the presence and degree of systolic dysfunction. Isoproterenol (IP) (18 patients) and D-isosorbitol (IS) (18 patients) have been used in the evaluation of hemodynamic response of DM. It has been verified equivalent responses such as: 1--decrease of ESV and end diastolic pressure (EDP); 2--increase of stroke volume and EF. The contractility indexes of left ventricle, however, showed different responses to the 2 substances: 1--with IP there was an increase of peak dp/dt and common peak isovolumetric pressure (CPIP 45 mmHg); 2--with IS there was no variation. The authors conclude that: 1--IP or similar drugs may be used during cardiac catheterization to evaluate the contractile reserve of the myocardium; 2--IS may be used in ambulatorial treatment of DM to improve ventricular function through a tendency to normalize intracardiac pressure-volume relation.
 ...
PMID:[Cardiac performance and hemodynamic response under the effect of isoproterenol and D-isosorbitol in patients with dilated cardiomyopathy]. 262 88

Hemodynamic activities of dobutamine enantiomers were studied in either control rats or those infused with isoproterenol (400 micrograms/kg/hr) for 4 days. In control animals prazosin attenuated the effects of (+/-)-dobutamine on cardiac output by approximately 50%; remaining activity was blocked by propranolol. After isoproterenol infusion (+/-)-dobutamine was less efficacious and the blocking effects of prazosin were greater than 90%. Isoproterenol infusion had no effect on (-)-dobutamine-mediated (alpha-1 adrenoceptor agonist) increases in cardiac output and these actions were blocked by prazosin. By contrast, compared to (+/-)- and (-)-dobutamine, effects of (+)-dobutamine (beta adrenoceptor agonist) on cardiac output were modest, not altered by prazosin and were blocked by propranolol; (+)-dobutamine was inactive after isoproterenol infusion. (-)-Dobutamine increased systemic vascular resistance in both control and isoproterenol infused rats, whereas (+)-dobutamine was inactive. (+/-)-Dobutamine increased systemic vascular resistance only in isoproterenol-infused rats. All increases in systemic vascular resistance were blocked by prazosin. Neither (+/-)- nor (+)-dobutamine significantly altered stroke volume. By contrast, (-)-dobutamine resulted in prazosin-sensitive increases in stroke volume in both control and isoproterenol-infused rats. In control animals, (+/-)-, (+)- and (-)-dobutamine increased heart rate in a dose-dependent manner; chronotropic effects of (-)-dobutamine were less than those of either (+/-)- or (+)-dobutamine. Chronotropic effects were not demonstrable in isoproterenol-infused animals. These data support the notion that in control rats cardiac output may be increased by either alpha or beta adrenoceptor stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Role of the alpha agonist activity of dobutamine in mediating cardiac output: effects of prolonged isoproterenol infusion. 288 11

A 21-year-old black man with sickle cell disease who has received blood transfusions for 11 years because of recurrent stroke has had a decline in numbers of circulating lymphocytes and T4 cells over the past four years. Two and a half years ago persistent generalized lymphadenopathy developed, associated with a positive test for human immunodeficiency virus (HIV) antibody. For the past seven months he has had a pruritic maculopapular rash, primarily on the extensor surfaces of the extremities. Multiple skin biopsies revealed only nonspecific perivascular infiltrates of mononuclear cells. This rash appears to be an unusual manifestation of HIV infection, and may be an indicator of impending AIDS.
 ...
PMID:Unusual chronic maculopapular rash associated with human immunodeficiency virus infection. 292 31

Patients with pulmonary hypertension challenge the anesthesiologist with complex alterations of hemodynamic function. To study the effects of multiple therapeutic interventions, a stable model of pulmonary hypertension in sheep was developed using continuous infusion of the vasoconstrictor U46619, a thromboxane A2-mimetic. The pulmonary and systemic effects of four pulmonary vasodilators (prostaglandin E1, isoproterenol, prostacyclin, and nifedipine) were compared at doses producing equivalent reduction in systemic blood pressure. Although all four drugs decreased pulmonary artery pressure and resistance, distinct differences in drug hemodynamic profiles were found. Prostaglandin E1 and isoproterenol demonstrated the greatest pulmonary specificity, increased cardiac output significantly, and decreased pulmonary vascular resistance. Prostaglandin E1 produced the largest decrease in pulmonary artery pressure (from 31 +/- 1 to 22 +/- 2 mm Hg). Isoproterenol markedly increased heart rate (from 119 +/- 6 to 182 +/- 10 beats/min) and resulted in significant dysrhythmias that necessitated limiting infusion of this drug; isoproterenol did not affect stroke volume. Prostacyclin demonstrated intermediate pulmonary specificity and produced the largest increase in cardiac output (from 1.7 +/- 0.2 to 3.1 +/- 0.3 L/min). Nifedipine exhibited the least pulmonary specificity and was the least effective agent in decreasing pulmonary artery pressure. In this model different pulmonary vasodilators exerted different hemodynamic effects, suggesting that appropriate drug selection for treatment of pulmonary hypertension should depend on baseline heart rate and rhythm, pulmonary artery pressure, systemic artery pressure, arterial oxygenation, and cardiac output.
 ...
PMID:Hemodynamic profiles of prostaglandin E1, isoproterenol, prostacyclin, and nifedipine in vasoconstrictor pulmonary hypertension in sheep. 329 83

This study investigated vascular responsiveness in stroke-prone spontaneously hypertensive rats (SHRSP) and the effect of antihypertensive treatment on this responsiveness. Weanling (4-week-old) male and female SHRSP and Wistar-Kyoto rats (WKY) received either the antihypertensive combination treatment of hydralazine plus hydrochlorothiazide in drinking water or tap water alone (controls) for 15 weeks. Whereas the antihypertensive combination prevented the development of hypertension in treated SHRSP (SHRSP-T), blood pressure remained unchanged in treated WKY (WKY-T). Femoral arterial smooth muscle responsiveness to KCl, norepinephrine, and calcium (in the presence of either 40 mM KCl or 1 microM norepinephrine) was not altered in SHRSP when compared with WKY. A significant increase in the sensitivity of femoral arteries to KCl and calcium (in the presence of 40 mM KCl) was seen, however, in SHRSP-T and WKY-T. An increased sensitivity to norepinephrine and calcium (in the presence of 1 microM norepinephrine) was seen only in SHRSP-T. Isoproterenol-induced relaxation was significantly attenuated in both SHRSP and SHRSP-T. Relaxation induced by sodium nitroprusside and calcium (membrane stabilization) was not different between the four groups. These results show that femoral arterial smooth muscle responsiveness to vasoconstrictor stimuli is not altered in SHRSP but that beta-adrenergic-mediated relaxation is attenuated. Antihypertensive treatment resulted in an enhanced responsiveness to these vasoconstrictor stimuli but had no effect on the relaxation properties of femoral arterial smooth muscle.
 ...
PMID:Vascular reactivity in the spontaneously hypertensive stroke-prone rat. Effect of antihypertensive treatment. 357 Apr 24

The effects of administration of anabolic steroids (SG, n = 6), endurance training (EG, n = 7) and a combination of steroid administration (Methandienone R) and training (ESG, n = 7) on systolic time intervals (STI) in the dog heart were compared with control dogs (CG, n = 7) by a catheterization technique. Isoproterenol infusion was used as a positive inotropic load. Physical performance was checked with submaximal exercise test, a 30 beats min-1 decrease in heart rate response was considered a sufficient training effect. During isoproterenol infusion, exercise was found to enhance the pump performance of left ventricle and increased stroke volume was related to shortened pre-injection period (PEP) (P less than 0.05), whereas steroid administration failed to induce any significant differences in PEP or PEP/LVET (LVET = left ventricular ejection time) when compared with CG. However, when steroid administration was combined with endurance training, both PEP and PEP/LVET were lengthened significantly in comparison with EG (P less than 0.05 and P less than 0.01, respectively). In conclusion, it seems that the anabolic steroids affected the STIs only, when their administration was combined with endurance training.
 ...
PMID:The effects of anabolic steroids and endurance training on systolic time intervals in the dog. 359 76

The effect of an anabolic steroid on canine left ventricular function was studied by catheterization exposing control (n = 7) and methandienone-treated (n = 6) dogs to pacing, volume and isoproterenol tests at the beginning of the experiment and 6 weeks later. The physical performance of the animals was evaluated by submaximal exercise test (SMT), in which the steroid-treated dogs had lower heart rate than the sedentary controls (P less than 0.001). Heart weight was greater in the steroid than in the control group (P less than 0.05). Isoproterenol infusion increased the maximum value of the left ventricular pressure curve (dP/dtmax) less in the steroid-treated than in the control animals (P less than 0.05). Also heart rate was lower in the steroid than in the control group after inotropic load, while end-diastolic, end-systolic and stroke volumes decreased significantly more in the control group (P less than 0.05). Systemic vascular resistance decreased in the steroid treated animals, but remained unchanged in the control group (P less than 0.05 between the groups). During volume overload dP/dtmax increased in the control group but decreased slightly in the steroid group (P less than 0.05 between the groups). The pressure-volume diagram showed that the left ventricle of the steroid-treated animals worked on higher ventricular volumes than in the control group. In conclusion, long-term methandienone treatment results in cardiac hypertrophy in dogs, reduces its response to an inotropic loads and leads to working on larger ventricular volumes.
 ...
PMID:Anabolic steroids alter the haemodynamic responses of the canine left ventricle. 360 11


<< Previous 1 2 3 4 5 6 7 8 Next >>