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

Review of the epidemiology of atherothrombotic brain infarction (ABI) based largely on 18 years of prospective data from the Framingham cohort reveals that stroke is a potent force in morbidity and mortality, that hypertension is its dominant precursor, that it can be predicted and suggests that only a preventive approach can substantially reduce stroke morbidity. Data from Framingham on the relative frequency of the major types of stroke found in the community reveal that 57 percent are due to ABI and only 17 percent to intracranial hemorrhage--two-thirds of which is subarachnoid. Lacunar infarcts are common accounting for 13 percent of ABI's in men and 23 percent in women. Despite the sizeable geographic, seasonal and secular trends in stroke mortality, few environmental determinants of stroke have been uncovered. However, established hallmarks of the candidate for an atherothrombotic stroke include: hypertension (systolic or diastolic), glucose intolerance, high normal hemoglobin, the cigarette habit (men only), abnormal lipids (under age 60) and cardiac impairments. Many unresolved issues remain. Nevertheless, it is possible to identify a tenth of the general population from which half the strokes will emerge. This provides a rational basis for establishing a program of prevention.
Milbank Mem Fund Q Health Soc 1975
PMID:An evaluation of the epidemiology of atherothrombotic brain infarction. 104 23

A significant part of transient or permanent cerebral ischemic attacks (CIA) are due to arterio-arterial emboli issued from carotid plaques. Surgery for carotid disobstruction aims to take out emboligenic plaques by endarterectomy (associated to angioplasty or not). The adversaries of surgical treatment sustain two main assertions: 1. carotid stenoses are not very dangerous, because the definitive thromboses they create are easily compensated by the development of collaterals, so that the risk for stroke is low. 2. this low and late risk of spontaneous carotid thrombosis is not greater than the immediate one following carotid surgery. Those objections have been encountered in randomized North American studies (Nascet & Veterans) that have been published in 1991 and 1993. They show the usefulness of correctly done surgical correction as well as for symptomatic as asymptomatic stenoses. So do we it, presenting the results of our series (2.282 procedures in 1.868 patients). The results of our series show a low combined morbidity-mortality rate (1.7%), and a yearly stroke of 1.4%.
Bull Mem Acad R Med Belg 1994
PMID:[Role of carotid surgery in the prevention of cerebral infarction]. 779 52

In a transplanted heart, increased stroke volume secondary to the Starling mechanism and increased heart rate and contractility secondary to noradrenaline effect appear sequentially whereas they appear simultaneously in normal innervated heart. Cardiac output adaptation at exercise is thus delayed and responsible for metabolic acidosis and abnormally high exercise ventilation. Moreover, stroke volume adaptation to exercise is compromised by abnormally high right and left afterload and by systolic and diastolic impairement of the ventricular function related with chronic rejections' episodes.
Bull Mem Acad R Med Belg 1993
PMID:[Adaptation of the denervated heart to physical effort]. 831 53

In a logographic language culture, repeated (hand) writing is a common memory strategy for learning letters and Chinese characters. The purpose of this paper is to determine whether this strategy facilitates children's memory for pseudologographic characters and foreign letters. It also explores which aspect of writing, the use of stroke orders or the writing action itself, is responsible for the effect. First, third, and fifth grade Japanese children participated in the study. Results showed that, for all the subjects, characters and letters were better recalled when learned by writing rather than by looking only (Experiments 1 and 4). The advantage of writing was decreased, however, when the proper writing action prevented (i.e., when subjects were instructed to trace or write without feedback; Experiments 3 and 4) but not when the proper stroke orders were prevented (i.e., when subjects were instructed to write in reverse or random orders; Experiment 2). The results indicate that the writing action, rather than the use of stroke orders, is responsible for the effect.
Mem Cognit 1998 Jul
PMID:Repeated writing facilitates children's memory for pseudocharacters and foreign letters. 970 71

Recent theories suggest that the human cerebellum may contribute to the performance of cognitive tasks. We tested a group of adult patients with cerebellar damage attributable to stroke, tumor, or atrophy on four experiments involving verbal learning or attention shifting. In experiment 1, a verb generation task, participants produced semantically related verbs when presented with a list of nouns. With successive blocks of practice responding to the same set of stimuli, both groups, including a subset of cerebellar patients with unilateral right hemisphere lesions, improved their response times. In experiment 2, a verbal discrimination task, participants learned by trial and error to pick the target words from a set of word pairs. When age was taken into account, there were no performance differences between cerebellar patients and control subjects. In experiment 3, measures of spatial attention shifting were obtained under both exogenous and endogenous cueing conditions. Cerebellar patients and control subjects showed similar costs and benefits in both cueing conditions and at all SOAs. In experiment 4, intra- and interdimensional shifts of nonspatial attention were elicited by presenting word cues before the appearance of a target. Performance was substantially similar for cerebellar patients and control subjects. These results are presented as a cautionary note. The experiments failed to provide support for current hypotheses regarding the role of the cerebellum in verbal learning or attention. Alternative interpretations of previous results are discussed.
Learn Mem
PMID:Preserved performance by cerebellar patients on tests of word generation, discrimination learning, and attention. 1045 11

Early olfactory preference learning in rat pups occurs when novel odors are paired with tactile stimulation, for example stroking. cAMP-triggered phosphorylation of cAMP response element binding protein (pCREB) has been implicated as a mediator of learning and memory changes in various animals (Frank and Greenberg 1994). In the present study we investigate whether CREB is phosphorylated in response to conditioned olfactory training as might be predicted given the proposed role of the phosphorylated protein in learning. On postnatal day 6, pups were trained for 10 min using a standard conditioned olfactory learning paradigm in which a conditioned stimulus, Odor, was either used alone or paired with an unconditioned stimulus, Stroking (using a fine brush to stroke the pup). In some instances stroking only was used. The pups were sacrificed at 0, 10, 30, or 60 min after the training. Using Western blot analysis, we observed that the majority of olfactory bulbs in conditioned pups (Odor + Stroking) had a greater increase in pCREB activation at 10 min after training than pups given nonlearning training (Odor only or Stroking only). The phosphorylated protein levels were low at 0 min and at 60 min after training. This is in keeping with the slightly delayed and short-lived activation period for this protein. The localization of pCREB increases within the olfactory bulb as seen by immunocytochemistry. Naive pups were not exposed to odor or training. There was a significantly higher level of label in mitral cell nuclei within the dorsolateral quadrant of the bulb of pups undergoing odor-stroke pairing. No significant differences were observed among nonlearning groups (Naive, Odor only, or Stroking only) or among any training groups in the granule or periglomerular cells of the dorsolateral region. The localized changes in the nuclear protein are consistent with studies showing localized changes in the bulb in response to a learned familiar odor. The present study demonstrates that selective increases in pCREB occur as an early step following pairing procedures that normally lead to the development of long-term olfactory memories in rat pups. These results support the hypothesized link between pCREB and memory formation.
Learn Mem
PMID:pCREB in the neonate rat olfactory bulb is selectively and transiently increased by odor preference-conditioned training. 1064 65

We quantified systemic ventriculo-arterial coupling in the pressure-volume (PV) plane, using a model of elastic chambers of the cardio-vascular system. In such a model, the ratio between left ventricular (LV) end-systolic elastance, and effective arterial elastance measures the coupling between the heart and the systemic vasculature, and the effects of cardiac diseases and of vasoactive agents on the coupling relationship can be independently evaluated in vivo. Furthermore, the analysis in the PV plane gives insights into LV mechanical efficiency, defined by the ratio between stroke work and pressure-volume area. Our results demonstrating that an augmentation of aortic compliance decreases the energetic cost of LV ejection should be considered when replacing the thoracic aorta by an artificial prosthesis. The homeometric autoregulation, suggesting a mechanism by which the heart can maintain a constant stroke volume, in the face of increased afterload, without using the Starling mechanism and independently of baroreflex integrity, is of paramount importance in heart transplant patients. Indeed, such patients, although lacking cardiac innervation, can adapt their cardiac output, stroke volume, end-systolic and end-diastolic pressures, without simultaneous changes in heart rate. Finally, our data demonstrate that the acutely ischemic LV must face an hostile hemodynamic environment, characterised by early vasoconstriction, later combined with decreased vascular compliance. These results are important when choosing vasoactive agents in the setting of acute myocardial infarction.
Bull Mem Acad R Med Belg 2002
PMID:[Experimental study of systemic ventriculo-arterial coupling. Effects of modifications of thoracic aortic mechanical properties and myocardial ischemia on left ventricular performance]. 1255 77

The Women's Health Initiative Study is the first large randomized controlled trial for primary prevention, comparing the beneficial or adverse effects of an oral continuous-combined regimen of conjugated estrogens + medroxyprogesterone acetate, vs placebo in late postmenopausal women. This study brings evidence for an absence of preventive cardiovascular effects of hormone replacement therapy (HRT), shows for the first time a small increase in risk for coronary disease, and confirms a small increased risk for invasive breast cancer from four-five years of treatment on, a reduction of risk of colorectal cancer and osteoporotic fractures, and a moderate increase in other already known cardiovascular risks during HRT, such as venous thromboembolism and stroke. Although this study has inherent limitations and may be criticised, and the observed risks are restricted, it forces the physician to better respect known contra-indications (a.o. vascular) to HRT, to carefully weigh the benefit/risk balance of the patients, shorten HRT administration (4-5 years?), use minimal effective hormone dosages, preferably by non-oral route, and change for new compounds with more selective estrogenic action, which are under development.
Bull Mem Acad R Med Belg 2003
PMID:[What scientific and clinical findings will result from the controlled trial "Women's Health Initiative"?]. 1285 99

Despite their purported neuroanatomic and functional isolation, empirical evidence suggests that sometimes conscious explicit processes can influence implicit motor skill learning. Our goal was to determine if the provision of explicit information affected implicit motor-sequence learning after damage to the basal ganglia. Individuals with stroke affecting the basal ganglia (BG) and healthy controls (HC) practiced a continuous implicit motor-sequencing task; half were provided with explicit information (EI) and half were not (No-EI). The focus of brain damage for both BG groups was in the putamen. All of the EI participants were at least explicitly aware of the repeating sequence. Across three days of practice, explicit information had a differential effect on the groups. Explicit information disrupted acquisition performance in participants with basal ganglia stroke but not healthy controls. By retention (day 4), a dissociation was apparent--explicit information hindered implicit learning in participants with basal ganglia lesions but aided healthy controls. It appears that after basal ganglia stroke explicit information is less helpful in the development of the motor plan than is discovering a motor solution using the implicit system alone. This may be due to the increased demand placed on working memory by explicit information. Thus, basal ganglia integrity may be a crucial factor in determining the efficacy of explicit information for implicit motor-sequence learning.
Learn Mem
PMID:Providing explicit information disrupts implicit motor learning after basal ganglia stroke. 1528 81

Oxidative stress underlies many forms of vascular disease as well as tissue injury following ischemia and reperfusion. The major source of oxidative stress in the artery wall is an NADPH oxidase. This enzyme complex as expressed in vascular cells differs from that in phagocytic leucocytes both in biochemical structure and functions. The crucial flavin-containing catalytic subunits, Nox1 and Nox4, are not found in leucocytes, but are highly expressed in vascular cells and upregulated with vascular remodeling, such as that found in hypertension and atherosclerosis. The difference in catalytic subunits offers the opportunity to develop "vascular specific" NADPH oxidase inhibitors that do not compromise the essential physiological signaling and phagocytic functions carried out by reactive oxygen and nitrogen species. Nitric oxide and targeted inhibitors of NADPH oxidase that block the source of oxidative stress in the vasculature are more likely to prevent the deterioration of vascular function that leads to stroke and heart attack, than are conventional antioxidants. The roles of Nox isoforms in other inflammatory conditions are yet to be explored.
Mem Inst Oswaldo Cruz 2005 Mar
PMID:Mechanisms for suppressing NADPH oxidase in the vascular wall. 1596 5


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