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)

We reported earlier that brain activation by 10 s of cortical electroshock caused prolonged elevation of brain lactate without significant change in intracellular pH, brain high-energy phosphorylated metabolites, or blood gases. The metabolic state of the elevated lactate has been investigated in further experiments using combined, in vivo 1H-observed 13C-edited nuclear magnetic resonance spectroscopy (NMRS), homonuclear J-edited 1H-NMRS, and high-resolution 1H-NMRS of perchloric acid extracts to monitor concentrations and 13C-isotopic fractions of brain and blood lactate and glucose. We now report that electroshock-elevated lactate pool in rabbit brain approaches equilibrium with blood glucose within 1 h. There was nearly complete turnover of the raised lactate pool in brain; any pool of metabolically inactive lactate could not have been > 5% of the total. In the same experiments, blood lactate underwent < 50% turnover in 1 h. The new 1H-spectroscopic methods used for these experiments are readily adaptable for the study of human brain and may be useful in characterizing the metabolic state of elevated lactate pools associated with epilepsy, stroke, trauma, tumors, and other pathological conditions.
 ...
PMID:Cerebral lactate turnover after electroshock: in vivo measurements by 1H/13C magnetic resonance spectroscopy. 140 Jun 41

From August 1987 through December 1989 all consecutive conscious patients younger than 70 years with a recent (less than 48 h) brain infarction of the carotid territory were prospectively included in the study. Blood samples for fasting blood glucose and glycosylated haemoglobin (HbA1c) were taken after a median delay of 23 h of the onset of symptoms. The severity of hemiparesis was assessed on admission, at 1 week, 3 weeks, and 3 months. The functional outcome was assessed at 3 months. Computed cerebral tomography was performed on admission, and later on at 3 weeks or 3 months. The brain infarct volume was measured from the CTs. The patients were diagnosed to have prestroke normoglycemia (n = 76) and prestroke hyperglycemia (n = 23) on basis of the HbA1c level. The case fatality rate, severity of hemiparesis, functional outcome, and infarct size did not differ between these 2 groups. On the other hand, fasting blood glucose level of the non-diabetics correlated strongly with the severity of hemiparesis and predicted stroke outcome. A statistically significant correlation was observed between blood glucose values and the volumes of cortical infarcts in non-diabetics. Because prestroke blood glucose level, in contrast to post-stroke blood glucose level, did not have any predictive value concerning stroke outcome it is concluded that high fasting blood glucose values after stroke reflect a stress response to a more severe ischemic brain lesion.
 ...
PMID:Blood glucose, glycosylated haemoglobin, and outcome of ischemic brain infarction. 140 98

A consecutive series of 327 patients (188 males, 139 females; mean age 68.4, SEM 1.33) were hospitalized within 12 h of the onset of their first-ever hemispheric infarct. Three groups of patients were identified: diabetics (n = 70), non-diabetic hyperglycaemics (n = 93) and normoglycaemics (n = 164). Case-fatality ratios at 30 days after stroke were 38.6%, 22.6% and 9.2% (P less than 0.001) respectively, whereas the causes of death and functional outcome of survivors were not significantly different between the groups. Mean admission serum glucose levels (SGLs) of decreased, impaired/unchanged and improved patients within each one of the three groups, were also not significantly different as opposed to their mean Canadian Neurological Scale (CNS) scores at entry (P less than 0.01). Among patients with less severe initial neurological deficit (i.e., CNS score greater than or equal to 7.0), 82.6% of non-diabetic hyperglycaemic subjects fared well, in comparison with 56.5% of diabetic and 70.1% of normoglycaemic individuals. The size of the infarcted areas at the second CT correlated with mean CNS scores (P less than 0.01) but not with mean SGLs on admission. The site of the ischaemic areas did not correlate with mean SGLs at entry. Therefore the influence of initial SGLs on the clinical course of the present series of patients is questionable or, alternatively, varied probably according to the pattern of residual cerebral blood flow after arterial occlusion.
 ...
PMID:Does hyperglycaemia play a role on the outcome of acute ischaemic stroke patients? 140 20

Ingestion of approximately 30-60 g of carbohydrate during each hour of exercise will generally be sufficient to maintain blood glucose oxidation late in exercise and delay fatigue. Since the average rates of gastric emptying and intestinal absorption exceed 1,250 ml.h-1 for water and solutions containing up to 8% carbohydrate, exercising people can be supplemented with both carbohydrate and fluids at relatively high rates. When cyclists exercise at competitive intensities for 2 h in the heat with a sweat rate of 1,400 ml.h-1, it is clear that the closer that fluid consumption matches sweating rate (at least up to 80% of sweating rate), the better. Increasing dehydration, due to inadequate fluid consumption, directly impairs stroke volume, cardiac output, and skin blood flow, which results in larger increases in body core temperature, heart rate, and ratings of the difficulty of exercise. This same phenomenon probably also applies to running, which argues against the notion that a certain amount of dehydration (i.e., up to 3%) is permissible and without major cardiovascular consequences. However, runners generally drink only 500 ml.h-1 of fluid and thus allow themselves to dehydrate at rates of 500-1,000 ml.h-1. The performance question boils down to "Will the time lost as a result of drinking larger volumes be compensated by the physiological benefits drinking produces and the faster running pace that might be achieved during the last half of the race?" However, if the goal is safety, which means minimizing hyperthermia, there is no question that the closer that the rate of drinking can match the rate of dehydration, the better.
 ...
PMID:Benefits of fluid replacement with carbohydrate during exercise. 140 5

To investigate further the relations between cortical energy metabolism and neuropsychological impairment after unilateral thalamic lesion, 55 patients underwent positron emission tomography studies of either cortical oxygen consumption or glucose utilisation, including eight repeat studies, at times ranging from 4 days to 98 months after the onset of the lesion [stroke (n = 44) or stereotaxic VL-Vim thalamotomy performed for movement disorders (n = 11)]. Patients with thalamotomy were also studied preoperatively and the surgery induced a significant fall in cortical metabolism on both sides (more so ipsilaterally); post-operatively the magnitude of the ipsilateral cortex hypometabolism was positively correlated to the severity of global neuropsychological impairment; similar but less significant findings were obtained for the ipsilateral/contralateral cortical metabolic asymmetry. With respect to the whole patient sample, the cortical metabolic asymmetry was initially pronounced, with subsequent monoexponential recovery, in the cognitively impaired study group, but it was only mild and showed no meaningful trend for recovery in the cognitively unaffected study group; yet even soon (< 3 months) after thalamic lesion there was a noticeable overlap of individual asymmetry values among the two study groups. These results lend further support to the view that the neuropsychological impairment that frequently follows unilateral thalamic lesions is reflected in a depression of synaptic activity in both the overlying and the contralateral cerebral cortices. For individual patients, this study also illustrates the potentially misleading nature of the measured cortical metabolic asymmetry with respect to neuropsychological status, especially at late times after lesion, in part because side to side metabolic ratios do not reflect bilateral changes.
 ...
PMID:Thalamocortical diaschisis: positron emission tomography in humans. 143 57

The introduction of positron emission tomography (PET) as a powerful imaging modality has played a major role in the understanding of the pathophysiological bases for cerebrovascular disorders. PET is the only technique that allows measurement of regional cerebral blood flow, blood volume, oxygen extraction fraction, and oxygen and glucose metabolism with detail and accuracy. Using PET, these physiological parameters can be measured to determine the extent of the disease from the early stages of cerebrovascular disorders to acute cerebral infarction. Significant hemodynamic and metabolic abnormalities are noted in chronic ischemia, but no structural changes are noted on anatomic images. PET studies have shown that in many patients in the early phases (10 to 12 hours) of clinically diagnosed acute stroke, a substantial area of ischemia exists, which, if untreated, will become irreversibly damaged. Similar to the results achieved in patients with acute myocardial infarction, appropriate intervention in patients with cerebrovascular disorders may significantly reduce the extent of injury to the brain. PET also has been useful in predicting functional recovery and monitoring the effects of various therapeutic approaches. Although functional imaging of the brain with single photon emission computed tomography can successfully be used in the investigation of several disorders of the brain, its role in cerebrovascular disorders is quite limited. PET is a unique modality that studies ischemic diseases of the brain, and it potentially could play a significant role in the management of patients with cerebrovascular disease. This will be further realized when aggressive approaches are used routinely in the future.
 ...
PMID:Positron emission tomography in cerebrovascular disorders. 143 68

Positron emission tomographic studies of cerebral glucose metabolism have shown high diagnostic specificity in distinguishing among the degenerative dementias and differentiating between Alzheimer's disease (AD) and normal aging. The current investigation was undertaken to characterize the regional glucose metabolic deficits in AD, using cross-sectional and longitudinal study designs. All subjects met the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for AD (n = 45) or were normal (n = 20), and the AD subjects were subdivided into incipient and mild AD and moderate plus moderately severe subgroups based on the Global Deterioration Scale. The subjects underwent a non-contrast computed tomographic scan and a positron emission tomographic (PETT VI) scan. The AD subjects (n = 14) and normal control subjects (n = 15) received evaluations 2 to 3 years after baseline study. The brain regions that show glucose metabolic deficits cross-sectionally (temporal and parietal association areas, with lesser degrees of deficit in subcortical gray matter structures), over the stages of AD, also show further deficits longitudinally within the same AD subjects. The reduction in glucose metabolism is greater than would be expected from the degree of brain atrophy. The glucose metabolic deficits are discussed in the context of neuropathologic findings and neurotransmitter deficits in AD.
 ...
PMID:Topography of cross-sectional and longitudinal glucose metabolic deficits in Alzheimer's disease. Pathophysiologic implications. 144 81

1. Studies in animal models of stroke have provided an invaluable contribution to our current understanding of the pathogenesis of cerebral ischaemia. The strengths of stroke research in animals are: 1) the ability to control the severity, duration, location and cause of the ischaemia, variables which confound interpretation of human stroke data; 2) co-existent disease states and variations in cerebrovascular anatomy are avoided; and 3) physiological parameters such as blood pressure, blood gases, temperature and plasma glucose (all of which influence the magnitude of the ischaemic lesion) can be closely monitored and controlled. Taking all these things on board, it is possible to induce a consistent focal ischaemic lesion in animal models of stroke (e.g. the permanent occlusion of the middle cerebral artery (MCA) in the rat). This has resulted in the wide use of animal models for assessment of anti-ischaemic drug efficacy as well as for research into the pathophysiological sequelae of stroke. 2. Traditionally focal ischaemia models involved permanent occlusion of a major cerebral artery such as the MCA. However, since vessel occlusion is seldom permanent in human stroke more recent developments have incorporated reperfusion (following ischaemia) into the design of the animal model. This has been achieved by reversible occlusion of cerebral vessels using 1) intraluminal filaments; 2) microclips; 3) the abluminal application of potent and prolonged vasoconstrictors; or 4) the introduction of emboli into the cerebral circulation.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:New models of focal cerebral ischaemia. 145 62

This article reviews the evidence on pharmacologic therapy of hypertension in reducing morbidity and mortality from stroke and coronary heart disease (CHD) and considers the possible generalizability of these findings to diabetics. For malignant hypertension, benefits are large and obvious from uncontrolled case series. For severe hypertension, conclusive benefits have been shown in several randomized trials. For mild to moderate hypertension, however, it is necessary to consider meta-analyses of all individual trials. The most comprehensive of these shows reductions of 42% for total stroke (95% Cl, -33 to -50%; P < 0.0001) and 14% for all CHD (95% Cl, -4 to -22%; P < 0.01). The applicability to diabetics is unclear because they were excluded from most of the trials. The Hypertension Detection and Follow-Up Program included diabetics and reported subgroup analyses. The reduction in mortality among the actively treated diabetics of 5% was less than the 17% achieved in nondiabetics. It is unclear, however, whether the mortality reductions are truly different or reflect the play of chance. Because of the higher incidence of CHD events among diabetics with hypertension, a similar relative benefit would result in a much greater absolute risk reduction. Further, the drugs used adversely affect lipid and glucose metabolism. New antihypertensive drugs without these side effects may further improve the risk-to-benefit ratio of antihypertensive treatment, especially in diabetics, who are at a several-fold absolute increased risk or cardiovascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Pharmacologic therapy of mild to moderate hypertension: possible generalizability to diabetics. 145 56

Knowledge of the natural history of certain stroke subtypes is essential for the proper analysis and interpretation of clinical trials of stroke therapy. We evaluated the degree of weakness on admission and again 7 to 10 days later in 62 patients with pure motor hemiparesis (PMH) and 280 patients with motor deficits from other stroke syndromes (OSS). During the 7-to-10-day study interval, we found that the OSS group worsened slightly in motor function, whereas the PMH group improved (p = 0.01). Among those who improved in both groups, those in the PMH group improved to a greater extent than did those in the OSS group (p = 0.02). This occurred despite a greater frequency of worsening during the first 12 hours after stroke onset in the PMH group. By the fourth day following PMH onset, a majority of patients had improved, and this improvement was sustained until day 10. The two groups did not differ significantly in age, race, sex, history of cardiac disease, hematocrit, anticoagulation treatment, blood glucose, or medical complications in hospital. Lacunar infarcts occurred in 84% of PMH and 23% of OSS. Patients with PMH show significant spontaneous improvement in weakness within 7 to 10 days of admission, compared with patients with OSS. Stratification by admission stroke syndrome in clinical trials may be necessary before judging the efficacy, or lack thereof, of a therapeutic agent.
 ...
PMID:Neurologic improvement in pure motor hemiparesis: implications for clinical trials. 151 58


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>