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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of oxygen saturation and PCO2 on brain uptake of glucose analogues was studied in rabbits. Using a modified Oldendorf technique, 14C-labeled glucose analogues with a 3H2O reference standard were introduced into the cerebral circulation via the common carotid artery, and the radioactivity of the ipsilateral cerebral cortex was counted and expressed in terms of a brain uptake index (BUI). Severe hypoxia (oxygen saturation less than or equal to 18%) resulted in approximately a 40% decrease in the BUI of 2-deoxy-D-glucose and a 45% decrease in the BUI of 3-0-methyl-D-glucose. Severe hypercapnia (PCO2 = 100 mm Hg) caused a 45% decrease in the BUI of both of these glucose analogues. Hypercapnia superimposed on severe hypoxia had no additional effect. Hypocapnia (PCO2 = 15 mm Hg) increased the BUI of 3-0-methyl-D-glucose by 35% of the control value, and this increase was extremely sensitive to competitive inhibition. When BUI values were plotted against pH rather than PCO2 for the same experiments, there was a good correlation with the calculated linear regression. These results are compared with previous findings on pathologically induced changes in brain uptake of glucose analogues, and the possible role of blood flow is considered in detail.
Stroke
PMID:Effects of oxygen saturation and pCO2 on brain uptake of glucose analogues in rabbits. 0 Aug 21

In healthy, closed-chest dogs, dose-dependent depression of ventricular function was produced by the anesthetics halothane, methoxyflurane, and fluroxene, as evidence by decreases in left venticular stroke volume, stroke work, dP/dt, and an increased enddiastolic pressure. Myocardial blood flow and oxygen consumption decreased concomitantly and were correlated with aortic blood pressure decreases. There was no change in myocardial lactate extraction with halothane and methoxyflurane, suggesting that myocardial oxygenation was adequate in spite of the decrease in blood flow. However, even with marked increases in arterial lactate concentration during fluroxene anesthesia, extraction did not chance and, in fact, tended to decrease. The hemodynamic effects of halothane and methoxyflurane are similar to those previously reported in man, but those of fluroxene are different. Consequently, clinical speculation from these results is not justified at this time.
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PMID:Effects of inhalation anesthetics on cardiac function and metabolism in the intact dog. 0 33

Cerebral hemispheric blood flow and metabolism were measured before and after therapy with intracarotid infusion of combined PBZ and PPL in 15 patients with recent cerebral infarction. HBF was unaltered despite decrease in cerebral perfusion pressure. Cerebral hemispheric oxygen comsumption and carbon dioxide production decreased while cerebral hemispheric lactate production increased. Biphasic cerebral uptake of tyrosine was observed during and immediately after PBZ and PPL infusion. CSF HVA increased, indicating altered DA turnover. CSF 5HIAA levels also increased, suggesting altered 5HT turnover after PBZ and PPL. Release of cyclic AMP from ischemic brain into cerebral venous blood seen in the steady state was abolished after therapy. Cerebral hemodynamic studies suggest a functional balance between monaminergic neurogenic influences in the control of cerebral circulation. Imbalance of such controlling factors in ischemic brain may lead to paradoxical vascular responses to induced hypertension and hypotension. PBZ and PPL enhance such responses perhaps by increasing central neurotransmitter turnover and release. Further shift toward cerebral anaerobic metabolism may occur in ischemic brain following the use of phenoxybenzamine and propranolol. Worsening of neurological deficit occurred in four cases. Combined therapy with PBZ and PPL does not appear beneficial in the therapy of patients with recent stroke.
Stroke
PMID:Influence of adrenergic receptor blockade on circulatory and metabolic effects of disordered neurotransmitter function in stroke patients. 0 7

Cardiovascular and metabolic parameters were studied in dogs anesthetized with pentobarbital sodium, and while awake resting or exercising for 30 min at either 6.4 km/h, 10% grade (32% VO2 max) or 8.0 km/h, 16% grade (50% VO2 max). The anesthetized dogs had lower cardiac outputs, stroke volumes, arterial-mixed venous oxygen differences, oxygen uptakes, rectal temperatures, and higher diastolic and mean arterial pressures than awake resting dogs. Heart rates and arterial systolic pressures were similar in the two conditions. The increased oxygen uptakes during exercise were associated with approximately equal percentage increments in cardiac outputs and oxygen extractions. Cardiac output increases during exercise were largely due to increases in heart rates. Arterial CO2 tension and CO2 contents as well as venous O2 and CO2 gas tensions and contents declined, and pH and rectal temperatures increased during exercise. The dogs became alkalotic during exercise. Elevated central body temperatures appeared to be the major factor controlling respiration.
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PMID:Cardiovascular, respiratory, and metabolic adjustments to exercise in dogs. 1 2

Awake domestic pigeons, either maintained at 22 degrees C (series I) or acutely exposed at 2 degrees C (series II), were studied in a hypobaric chamber at 140 m and at various stages during a 4-week exposure to 4000 m. Steady-state pulmonary ventilation (Vg) and breathing pattern (VT, fr), oxygen consumption (MO2), O2 concentrations and pressures in the arterial (a) and mixed venous blood (v), hematocrit (Ht) and acid-base status in arterial blood, systolic blood pressure and heart frequency (fH) were measured. From these data cardiac output (Vb) and stroke volume (Vs), ventilatory and circulatory requirements (Vg/MO2, Vb/MO2), extraction of O2 from inspired air (EgO2) and blood EbO2), and capacitance coefficient of blood for oxygen (betabo2) were calculated. At 140 m, by comparison with predicted values for mammals of same body weight, pigeons at 22 degrees C extracted more O2 from the inspired gas, with lower fR, larger VT, similar Vg; they extracted O2 from the blood like mammals, with lower fH, larger VS, greater Vb, similar betabO2=70 mumol-L-1-torr-1. Acute exposure to 2 degrees C provoked a two-fold increase in MO2 which was achieved by doubling Vg and increasing O2 extraction from the blood. At 4000 m, in both series, pigeons hyperventilated within the first 30 min, with a resultant hypocapnic alkalosis comparable to that in mammals. Further hyperventilation with consequent greater hypocapnia and increase of arterial PO2 was complete beyond 3 hr. After a few weeks, the pH remained 0.07 above control normoxic value, Ht increased from 45 to 52%, betabO2 reached about 172 mumol-L-1-torr-1. At 2 degrees C, Vb also increased, mainly due to tachycardia.
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PMID:Ventilatory and circulatory O2 convection at 4000 m in pigeon at neutral or cold temperature. 1 65

The application of the Starling resistor concept of the lungs during continuous positive pressure ventilation (CPPV) was evaluated. Ventilation and hemodynamics were studied in eight anesthetized and paralyzed dogs before and during the use of CPPV. CPPV resulted in an increase in transpulmonary pressure and functional residual capacity (FRC), and a decrease in arterial pH and mixed venous oxygen tension (PvO2). Cardica index decreased 32% (p less than 0.01) and stroke volume 51% (p less than 0.01). Neither right nor left transmural pressures changed but pulmonary vascular resistance increased 189% (p less than 0.01). This study supports the concept that the pulmonary vasculature behaves as a Starling resistor during the use of CPPV. The increase in pulmonary vascular resistance must be considered when transpulmonary pressure is raised by CPPV.
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PMID:Application of the Starling resistor concept to the lungs during CPPV. 1 9

1. Oxygen consumption and central haemodynamics were recorded at rest and during exercise in fifty-one men with essential hypertension (W.H.O. stage I) and repeated after 1 year on a single drug: alprenolol (n equals 10), atenolol (13) metoprolol (12) and timolol (16). 2. Mean arterial pressure was significantly reduced in all groups at rest (11-18%) and during exercise (5-11%). Heart rate was significantly reduced in all groups (20-28%) at rest and (17-26%) during exercise. Owing to increase in supine resting and exercise stroke volume in the alprenolol and atenolol group, cardiac index decreased less than heart rate---in contrast to the timolol group where cardiac index was decreased 26-32%. The calculated post-treatment total peripheral resistance was significantly increased at rest and during exercise in the timolol group. In the other groups the total peripheral resistance was significantly increased at rest when sitting, but not at rest when supine and during exercise. 3. It is concluded that the major haemodynamic changes induced in subjects with moderate and mild essential hypertension by these different beta-receptor blockers are the same, but that minor differences exist with respect to effect upon stroke volume and total peripheral resistance.
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PMID:Haemodynamic long-term effects of beta-receptor-blocking agents in hypertension: a comparison between alprenolol, atenolol, metoprolol and timolol. 1 59

We reported on the haemodynamic effects of 0.03 mg/kg flunitrazepam during surgical procedures in neuroleptanalgesia in 39 patients with congenital or acquired heart diseases, functional class II-IV. The benzodiazepine derivative did not cause any relevant effect on the inotropic state of the myocardium. There were only minor changes in cardiac index, stroke index, right and left atrial pressure. Changes in arterial pressure and left ventricular pressure during and immediately after surgical procedures, and in arterial perfusion pressure during extracorporeal circulation, as well as an only short lasting increase in heart rate were demonstrative a peripheral vasodilator effect. The decrease in ventricular work and myocardial oxygen consumption are of value in patients with coronary heart disease, especially immediately after surgical procedures. Flunitrazepam is considered an additional drug during neuroleptanalgesia, when hypertension is causing some problems.
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PMID:[Cardiovascular effects of flunitrazepam (rohypnol, RO-5-4200) (author's transl)]. 1 70

The study was undertaken to investigate the acute haemodynamic effects of bunitrolol (0-2-hydroxy-3-(tert.butylamino)-propoxy)-bity. Right and left heart catheterization was performed in eleven patients with documented coronary artery disease. After bunitrolol (10 mg i.v.), there was a statistically significant decrease in left ventricular and aortic systolic pressures left ventricular end-diastolic pressure, aortic diastolic and mean pressures, pressure-rate product and compliance index (delta P/delta V). Left ventricular dp/dt, left ventricular dp/dt over isovolumic pressure, systemic resistance and heart rate tended to decrease, stroke volume and left ventricular stroke work index tended to increase, without statistical significance. Cardiac index showed individual variations, the mean values for the group being unchanged. Correlation of left ventricular end-diastolic pressure and left ventricular stroke work index showed a shift toward improved ventricular function curve in most cases, deterioration in no instance. Supine exercise was performed in ten patients. Angina occurred in nine patients; in five only before and in four before and after beta-blockade. Post-drug exercise heart rate, pressure-rate product and left ventricular end-diastolic pressure were significantly lower, the latter also in the four patients who still presented exercise angina. It is concluded that certain beta-blockers can improve cardiac performance at rest and during exercise in patients with coronary artery disease. This is explainable on the basis of a more favourable balance between oxygen supply and demand, together with a less marked negative inotropic effect due to the partial agonist activity of the agent used in the study.
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PMID:Evidence for improved cardiac performance after beta-blockade in patients with coronary artery disease. 1 74

1. 2-Ethyl-3-(4-gamma-di-n-butylaminopropoxy-benzoyl)-indolizine hydrochloride (L 9394) induced in the ananesthetized dog a marked and long-lasting decrease in heart rate together with a transient reduction in blood pressure. 2. L 9394 decreased Robinson's index, an effect which suggests that the substance reduces the oxygen requirements of the heart. 3. L 9394 markedly increased coronary arterial blood flow. 4. L 9394 is endowed with non-competitive antiadrenergic properties. 5. L 9394 did not impair cardiac function since cardiac output and stroke volume increased appreciably during the initial phase of action and did not fall below the control values at any time thereafter. 6. The overall haemodynamic properties of L 9394, which were similar to those of amiodarone, are considered to be potentially valuable for the long-term treatment of angina pectoris.
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PMID:Amiodarone-like haemodynamic and non-competitive antiadrenergic properties of a benzoyl-indolizine. 2 Jan 16


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