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

In order to determine the effect of lidocaine in focal cerebral ischemia, the left middle cerebral artery was transorbitally occluded in twenty cats. Eleven received lidocaine hydrochloride intravenously. The infusion was begun half an hour prior to clip occlusion and the rate was adjusted to maintain an isoelectric EEG. Nine cats served as controls, receiving an equivalent volume of 5% dextrose 0.2% saline. Thirteen animals (7 lidocaine-treated and 6 control) were sacrificed after six hours of left middle cerebral artery occlusion without reperfusion. In the remaining seven cats, the vessel was occluded for four hours prior to sacrifice. Ischemic neuronal alteration was assessed by both histochemical (2'3'5' triphenyl-2H-tetrazolium hydrochloride reaction) and histological examination. With both durations of ischemia, there was no significant difference in the extent and severity of neuronal alterations between the lidocaine-treated and control groups of animals.
Stroke
PMID:An evaluation of the effect of lidocaine in experimental focal cerebral ischemia. 376 68

Eight ponies were anesthetized with a solution containing 50 mg of guaifenesin, 1 mg of ketamine, and 0.5 mg of xylazine X ml-1 of 5% dextrose in water. Anesthesia was induced by IV injection (1.1 ml X kg-1), followed by continuous IV infusion at 2.75 ml X kg-1 X hr-1. Heart rate, rate-pressure product, mean pulmonary artery pressure, and standard bicarbonate were not significantly changed throughout the study. Systolic, diastolic, and mean arterial pressures and left ventricular stroke work index were significantly decreased at 5 and 15 minutes after a bolus of the anesthetic solution was injected. Systolic blood pressure returned to within the base-line range at 30 minutes, but diastolic and mean arterial pressures were significantly decreased throughout the study. Cardiac index and arterial pH were decreased at 5 minutes only. Systemic vascular resistance was significantly decreased 60 minutes after bolus injection was given. Hypoventilation, as indicated by increased PaCO2, occurred 5 minutes after bolus injection was given.
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PMID:Cardiopulmonary effects of continuous intravenous infusion of guaifenesin, ketamine, and xylazine in ponies. 378 95

A method was developed to measure simultaneously the rate constants for glucose influx and glucose efflux, and the Michaelis-Menten constant (KM) and maximal velocity (Vmax) for glucose transport across the blood-brain barrier (BBB) in any selected brain area. Moreover, on the basis of a mathematical model, the local perfusion rate (LPR) and local unidirectional glucose transport rate (LUGTR) are calculated in terms of parameters of the time-activity curves registered over different brain regions; 11C-methyl-D-glucose (CMG) is used as an indicator. The transaxial distribution of activity in the organism is registered using dynamic positron-emission tomography (dPET). The method was used in 4 normal subjects and 50 patients with ischemic brain disease. In normals, the rate constant for CMG efflux was found to be 0.25 +/- 0.04 min-1 in the cortex and 0.12 +/- 0.02 min-1 in white matter. In the cortex, the KM was found to be 6.42 mumol/g and the Vmax was 2.46 mumol/g per minute. The LUGTR ranged from 0.43 to 0.6 mumol/g per minute in the cortex, and from 0.09 to 0.12 mumol/g per minute in white matter. The LPR was calculated to be 0.80-0.98 ml/g per minute for the cortex and 0.2-0.4 ml/g per minute for white matter. In patients with stroke, the ischemic defects appeared to be larger in CMG scans than in computed x-ray tomography (CT) scans. Prolonged reversible ischemic neurological deficit was associated with a significant fall in the LUGTR but no change in the LPR in the corresponding cerebral cortex. Normal LUGTR and significantly decreased LPR were registered in a patient with progressive occlusion of the middle cerebral artery. In a patient with transient ischemic attacks, a slightly reduced LPR and a disproportionally reduced LUGTR were observed before operation. After extra- and intracranial bypass surgery, the LPR became normal, whereas the LUGTR increased but did not achieve normal values.
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PMID:In vivo determination of the kinetic parameters of glucose transport in the human brain using 11C-methyl-D-glucose (CMG) and dynamic positron emission tomography (dPET). 387 36

The presence of hyperglycemia before brain ischemia increases stroke-related morbidity and mortality in experimental animals and humans. However, little is known of the effect of hyperglycemia on regional cerebral blood flow (rCBF). Acute hyperglycemia was induced in awake but restrained rats by intraperitoneal injection of 50% D-glucose. Regional flow was determined using [14C]iodoantipyrine and quantitative autoradiography. Elevation of plasma glucose from 11 to 39 mM was associated with a 24% reduction in rCBF when compared with controls that received normal saline. Intraperitoneal D-mannitol produced an elevation of plasma osmolality equivalent to that observed with glucose. However, rCBF was only reduced by 10%. Hyperglycemia appears to produce a global decrease in rCBF in awake rats that cannot be completely explained by the attendant increase in plasma osmolality. If a similar influence is present during brain ischemia, hyperglycemia could extend areas of critical flow limitation.
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PMID:Regional cerebral blood flow decreases during hyperglycemia. 392 83

Prenalterol, a beta1 agonist, was given in a single blind acute intravenous study to seven patients with cardiac failure (New York Heart Association class II and III). It was then given in a double blind crossover study of sustained oral prenalterol to six of them. As a result of dose titration studies the oral dose of prenalterol given was 100 mg twice a day in all patients. Erect bicycle sprint tests were performed to exercise tolerance before and after treatment had been started. Cardiac function was assessed at rest and during graded supine bicycle exercise by determining haemodynamic indices using a Swan-Ganz catheter and radionuclide left ventricular ejection fractions. In the intravenous study cardiac function was assessed at rest and during exercise after a control infusion of dextrose and after an infusion of 5 mg prenalterol. In the oral crossover study a placebo or prenalterol were given for two periods of two weeks; at the end of each period exercise tolerance was measured and cardiac function assessed at rest and during exercise. Throughout the study period there was no change in symptoms, medication, or exercise tolerance. Intravenous prenalterol significantly improved cardiac function; left ventricular ejection fraction and cardiac index increased and left ventricular filling pressure fell both at rest and during exercise. Sustained oral treatment with prenalterol, however, did not improve resting left ventricular filling pressure or left ventricular ejection fraction at rest or during exercise but did increase heart rate at rest, and mean blood pressure and peripheral vascular resistance at rest and during exercise; in fact, during exercise left ventricular filling pressure was significantly increased while cardiac index and stroke volume index were decreased by prenalterol. Sustained oral treatment with prenalterol did not have the beneficial effects on cardiac function produced by intravenous treatment and in fact had deleterious effect on the measured indices of cardiac function during exercise.
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PMID:Acute intravenous and sustained oral treatment with the beta1 agonist prenalterol in patients with chronic severe cardiac failure. 632 84

Naloxone and methylprednisolone sodium succinate (MPSS) may act in synergy to improve hemodynamics in patients with septic shock by enhancement of sympathomedullary discharge. This randomized double-blind study describes the effect of various dosing regimens of naloxone and MPSS upon hemodynamics and plasma catecholamines in patients with septic shock (n = 57). Consecutive bolus doses of naloxone were given 30 minutes apart (10 micrograms/kg;-100 micrograms/kg) and a single dose of MPSS (30 mg/kg); bolus doses of 5% dextrose in water solution plus single dose of MPSS as above; bolus dose of naloxone (30 micrograms/kg) followed by continuous infusion (30 micrograms/kg/hr for 1 hour) with single dose of MPSS as above; a bolus and continuous infusion of naloxone as above without MPSS; MPSS alone and standard therapy alone. In patients treated with bolus doses of naloxone in combination with MPSS, plasma levels of epinephrine and norepinephrine were increased approximately five-to tenfold. In patients treated with bolus plus continuous infusion of naloxone given with or without MPSS, only plasma epinephrine levels were increased. Systolic blood pressure and left ventricular stroke work index were improved within 15 minutes in groups which received naloxone and corticosteroids regardless of dose. In those groups, there were no changes in heart rate or filling pressure. Systemic vascular resistance improved significantly only in the group which received low dose bolus and continuous infusion of naloxone and MPSS. Naloxone and MPSS quickly improved cardiac function in patients with septic shock by enhanced sympathomedullary discharge and may be useful as an adjunct in the therapy of this disorder.
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PMID:Naloxone and methylprednisolone sodium succinate enhance sympathomedullary discharge in patients with septic shock. 639 57

Twenty-four urogenital isolates of coagulase-negative staphylococci were selected because of their demonstrated ability to inhibit Neisseria gonorrhoeae growth in vitro. These organisms showed quantitative differences in their growth-interfering capability as revealed by a flip-flop agar overlay method. The composition of the culture medium affected the production of antigonococcal activity. Antigonococcal activity was shown with the following media: GC agar base with Lankford defined supplement, brain heart infusion agar, trypticase soy agar, and dextrose starch agar, but not with the GC agar base with CVA enrichment. An antigonococcal activity was obtained in the liquid phase prepared from semisolid agar cultures for 10 of the 24 staphylococcal isolates, whereas no activity was found in the supernatant from liquid cultures. The production of antigonococcal activity by staphylococci in vitro is influenced by growth conditions.
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PMID:In vitro antigonococcal activity of urogenital coagulase-negative staphylococci. 678 83

Glycerol is a potent osmotic dehydrating agent with additional effects on brain metabolism. In doses of 0.25-2.0 g/kg glycerol decreases intracranial pressure in numerous disease states, including Reye's syndrome, stroke, encephalitis, meningitis, pseudotumor cerebri, central nervous system tumor, and space occupying lesions. It is also effective in lowering intraocular pressure in glaucoma and shrinking the brain during neurosurgical procedures. Hyperosmolality with rebound cerebral overhydration is of concern, especially in patients with altered blood brain barriers. They may be avoided if glycerol is administered on an intermittent rather than a continuous basis. Intravascular hemolysis does not occur with oral use. When administered intravenously, hemolysis can be minimized by using glycerol 10% in dextrose 5% with normal saline at rates of 6 mg/kg/min or less. However, intravenous doses of 1-2 g/kg every 2 hr can be administered safely in severe cases of elevated ICP. In such patients, glycerol serum concentration, serum osmolality and ICP monitoring are required to optimize glycerol therapy.
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PMID:Glycerol: a review of its pharmacology, pharmacokinetics, adverse reactions, and clinical use. 692 4

The capability of positron computed tomography (PCT) to delineate the substructures of the brain and its facility for accurately measuring the local tissue radioactivity concentration allow the application of tracer kinetic models for the study of local cerebral function in man. This principle and an adaptation of the 14C-deoxyglucose (DG) model of Sokoloff et al. with 18F-2-fluoro-deoxy-D-glucose (FDG) is being used at UCLA. Brookhaven National Laboratory, University of Pennsylvania, NIH, and the Massachusetts General Hospital to determine the local cerebral glucose metabolic rate (LCMRGIc) in normal man at rest and during sensory activation and the changes that occur in patients with a variety of cerebral disorders. Kinetic studies with PCT have been employed to measure the rate constants of the model in different gray and white matter structures of the brain in both normal and ischemic states. The precision of the method in normals has been shown to be about +/- 5% for 1.5-2.0 sq cm regions of the brain. Studies in normals have yielded values for hemispheric CMRGIc that are in agreement with measurement using the Kety-Schmidt technique and LCMRGIc values in agreement with values in monkeys using DG autoradiography. Studies in volunteers subjected to visual and auditory stimulation are demonstrating the potential of this technique for investigating the human brain's response to different stimuli. STudies in patients with stroke show excellent correlation between the degree, extent, and particular structures involved and the clinical symptoms. The method consistently detected hypometabolism in cortical, thalamic, and striatal tissues that were dysfunctional due to deactivation or damage but which appeared normal on x-ray CT. Studies in patients with partial epilepsy have shown hypometabolic zones that highly correlated anatomically with interictal EEG spike foci and were associated with normal x-ray CT studies in 77% of the patients studied. The studies on epilepsy at UCLA have resulted in the integration of the LCMRGIc study into the clinical workup of patients with partial epilepsy that are candidates for surgical resection of their epileptogenic focus (effective June 1979). Studies on Huntington's chorea, Parkinson's disease, aphasia, dementia, schizophrenia, and tumors are in early stage of investigation but also are providing exciting new results. Further studies are needed to determine the role of the local function information obtained with the PCT-FDG method in elucidating the basic mechanism and the potential to aid in improving the approach to medical therapy.
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PMID:Positron computed tomography studies of cerebral glucose metabolism in man: theory and application in nuclear medicine. 697 94

The ischemic myocardium utilizes glycogen as metabolic substrate. The effects of oral nutrition on the levels of glycogen in the myocardium and of myocardial glycogen content on myocardial tolerance to ischemia were studied. Rats were divided into groups and fed (a) rat chow, (b) rat chow plus 5% dextrose, and elemental diets (c) Flexical (Mead Johnson) or (d) Vital (Ross Laboratories). Another group was starved. All fed groups gained weight normally while the starved rats lost 23% of their body weight. Compared with the effect on rat chow, myocardial glycogen levels were elevated in the Flexical and starvation groups, while Vital depressed the level (P less than 0.01). Thus, both caloric intake and diet affected myocardial glycogen content. Elevation of myocardial glycogen content after starvation contrasted with glycogen disappearance from the liver. The level of myocardial glycogen and left ventricular function after global ischemia were correlated in dogs under cardiopulmonary bypass conditions. During 30 minutes of normothermic aortic cross-clamping, hearts with a preischemic myocardial glycogen content greater than 0.4 g% had less asystole or ventricular fibrillation. Their left ventricular function (stroke work index, myocardial contractility) upon reperfusion was substantially better than those with a myocardial glycogen level of less than 0.4 g%. Dietary manipulation and the nutritional status can thus affect the myocardial glycogen content and may be useful in protecting the myocardium from ischemia.
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PMID:Protection of ischemic myocardium: the roles of nutrition and myocardial glycogen. 711 54


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