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

Eleven patients with Takayasu Arteritis (TA) underwent angioplasty and stent placement in aorta, renal, carotid, subclavian and coronary arteries. Five wall stents were deployed in aorta in four patients. Indications for angioplasty and stent placement in aorta included hypertension in four patients and claudication and erectile impotence in one patient each. Post-procedure the peak systolic pressure gradient across the stenotic segment in the aorta disappeared. Six patients underwent angioplasty and stent placement in carotid arteries. Indications were syncope in 6 patients, loss of vision, stroke, transient ischaemic attack and seizures in one patients each. There was a marked improvement in symptoms in the patients following the procedure. For chronic total occlusion of subclavian arteries, two stents were deployed in two patients. Following the stent placement pulses in upper limb reappeared. Stents were also deployed to treat near total occlusion of right coronary artery and flow limited dissection of renal artery in one patient each. Complications of the procedure included pain in the back, mild hypertension, transient bradycardia and conduction block in one patient each. In conclusion, the stenotic and obliterative vascular lesions in TA can be managed successfully with angioplasty and stent placement. A long term follow up is required to determine the re-stenosis rate.
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PMID:Stent supported angioplasty in Takayasu arteritis. 995 22

Modern molecular biology has revealed vast numbers of large and complex proteins and genes that regulate body function. By contrast, discoveries over the past ten years indicate that crucial features of neuronal communication, blood vessel modulation and immune response are mediated by a remarkably simple chemical, nitric oxide (NO). Endogenous NO is generated from arginine by a family of three distinct calmodulin- dependent NO synthase (NOS) enzymes. NOS from endothelial cells (eNOS) and neurons (nNOS) are both constitutively expressed enzymes, whose activities are stimulated by increases in intracellular calcium. Immune functions for NO are mediated by a calcium-independent inducible NOS (iNOS). Expression of iNOS protein requires transcriptional activation, which is mediated by specific combinations of cytokines. All three NOS use NADPH as an electron donor and employ five enzyme cofactors to catalyze a five-electron oxidation of arginine to NO with stoichiometric formation of citrulline. The highest levels of NO throughout the body are found in neurons, where NO functions as a unique messenger molecule. In the autonomic nervous system NO functions NO functions as a major non-adrenergic non-cholinergic (NANC) neurotransmitter. This NANC pathway plays a particularly important role in producing relaxation of smooth muscle in the cerebral circulation and the gastrointestinal, urogenital and respiratory tracts. Dysregulation of NOS activity in autonomic nerves plays a major role in diverse pathophysiological conditions including migraine headache, hypertrophic pyloric stenosis and male impotence. In the brain, NO functions as a neuromodulator and appears to mediate aspects of learning and memory. Although endogenous NO was originally appreciated as a mediator of smooth muscle relaxation, NO also plays a major role in skeletal muscle. Physiologically muscle-derived NO regulates skeletal muscle contractility and exercise-induced glucose uptake. nNOS occurs at the plasma membrane of skeletal muscle which facilitates diffusion of NO to the vasculature to regulate muscle perfusion. nNOS protein occurs in the dystrophin complex in skeletal muscle and NO may therefore participate in the pathophysiology of muscular dystrophy. NO signalling in excitable tissues requires rapid and controlled delivery of NO to specific cellular targets. This tight control of NO signalling is largely regulated at the level of NO biosynthesis. Acute control of nNOS activity is mediated by allosteric enzyme regulation, by posttranslational modification and by subcellular targeting of the enzyme. nNOS protein levels are also dynamically regulated by changes in gene transcription, and this affords long-lasting changes in tissue NO levels. While NO normally functions as a physiological neuronal mediator, excess production of NO mediates brain injury. Overactivation of glutamate receptors associated with cerebral ischemia and other excitotoxic processes results in massive release of NO. As a free radical, NO is inherently reactive and mediates cellular toxicity by damaging critical metabolic enzymes and by reacting with superoxide to form an even more potent oxidant, peroxynitrite. Through these mechanisms, NO appears to play a major role in the pathophysiology of stroke, Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis.
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PMID:Endogenous nitric oxide synthesis: biological functions and pathophysiology. 1063 Jun 82

Disturbances of the autonomic nervous system are common in patients with various cerebrovascular diseases. They are attributed to damage of the central autonomic network, particularly in the frontoparietal cortical areas and in the brain stem, or to a disruption of the autonomic pathways descending from the hypothalamus via the mesencephalon, pons, and medulla to the spinal cord. The most common clinical problems include abnormalities in heart rate and blood pressure regulation, reflecting cardiovascular autonomic dysfunction, and asymmetric sweating with cold hemiplegic limbs, reflecting changes in the sudomotor and vasomotor regulatory systems. Bladder and bowel dysfunction and impotence are also frequent complaints after stroke, but the present knowledge concerning their prevalence and clinical significance is still limited. Cardiovascular autonomic dysfunction, which is mainly related to increased sympathetic activity, is most evident in the acute phase of stroke, whereas other autonomic disorders, such as abnormal sweating, are long-standing or even irreversible. In addition to the well-established sympathetic hyperfunction, abnormalities of the parasympathetic nervous system may also contribute to the autonomic imbalance after stroke. Reliable recognition of autonomic dysfunction using quantitative analysis methods is important, because these disturbances are not only subjectively disabling and uncomfortable, but they may also be prognostically unfavorable. Moreover, quantitative measurements also form the ground for successive treatment of various stroke-related autonomic disorders.
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PMID:Autonomic nervous system disorders in stroke. 1063 6

Diuretics in low doses have the greatest support among current available antihypertensives in that they have been shown to reduce total mortality, coronary mortality, stroke, and congestive heart failure in an important meta-analysis by Psaty. Recently, Messerli has linked longterm diuretic use to renal cell carcinoma in women. In some patients, diuretic use leads to increasing blood cholesterol and blood sugar levels. Impotence is a recognized side effect, with rates rising about twofold with low-dose chlorthalidone and fourfold with a higher dose. Certain population groups such as younger (<60 years) white males often do not respond to low-dose diuretic therapy with an adequate blood pressure fall. In females of a similar age group, Messerli calculates that prolonged diuretic therapy will prevent only one stroke and no coronary events nor any deaths for every renal cell carcinoma that is provoked. Despite these evident problems, the outcome data on hard endpoints in trials with initial low-dose diuretic therapy remain valid and convincing. Thus, it is argued, low- but not high-dose diuretics retain their primacy in the ranking of antihypertensive therapy.
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PMID:Diuretic downsides--but in low doses they still seem among the best authenticated antihypertensives. 1099 47

In Africa, a rise in complications of diabetes mellitus has gone in hand with the growing disease prevalence, clearly demonstrating the importance of assessing complications. Diabetes mellitus constitutes a major financial burden in developing countries in Africa with relatively limited resources. Ketoacidosis is observed in 24% of juvenile diabetes and is the inaugural sign in 76% of all cases, progressing to coma in 34%. Even in type 2 diabetes, acidoketosis occurs in 34% of the cases. Infection is particularly frequent and is often fatal in tropical Africa because of the involvement of Staphyococcus and Gram-negative microorganisms. Hyperleukocytosis and anemia are correlated with ineffective antibiotic therapy. Pulmonary tuberculosis is the ninth most frequent complication of diabetes. Overall mortality is 14.9 per 1000 person-years of diabetes. Mean age at death is 51.6 years for women and 57.6 years for men after a mean 12.5 year disease duration. Thirty percent of all deaths result from acute metabolic complications, infections and stroke. More than half of the patients with insulin-dependent-diabetes have retinopathy. Differences observed in patients with different ethnic origins is linked basically to unfavorable social and economic conditions that worsen the risk of poor blood glucose control. Retinopathy accounts for 32% of all ocular complications, similar to other African data and more generally in ophthalmology centers. The rate of neuropathy is high, reaching 70% in patients with microangiopathy. Impotence concerns 48.7% of the diabetic population with a mean age of 41.4+/-15.5 years. Coronary artery disease had a recognized influence on hemoglobin diseases, particularly when the coronarography is normal. Lower limb arteriopathy is observed in 18% of the diabetic patients.
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PMID:[Main complications of diabetes mellitus in Africa]. 1117 5

This review evaluates the current position of calcium channel blockers (CCB) in antihypertensive treatment in the light of three major comparative studies and two extensive meta-analyses. The latter both show that CCB are equivalent to conventional (initial beta-blocker or diuretic therapy) when total and cardiovascular mortality are the end points. Divergent points between the meta-analyses include stroke and myocardial infarction (MI). One meta-analysis compared CCB with conventional therapy, to find a small 13% reduction in stroke and a small, nonsignificant 12% increase in MI. The other meta-analysis found a 26% increase in MI when CCB were compared with all other therapies including the angiotensin converting enzyme (ACE) inhibitors. This increase was most robust (P < .001) when comparing CCB with ACE inhibitors, consonant with proposed protective effects of ACE inhibitors on cardiovascular risk. At present, only the comparison of CCB with conventional therapy, and not that with ACE inhibitors, rests on secure comparative data. When cost is compelling, conventional therapy is less expensive. For the individual patient, issues of quality of life (for example, impotence with diuretics and beta-blockers) might be decisive. Nonetheless, beta-blockers are preferred in postinfarct patients or in those with heart failure or unstable angina (a contraindication to dihydropyridines in the absence of beta-blockade). In others, the benefits of only a borderline stroke reduction with CCB versus an equally borderline increase in MI should be evaluated for each individual patient, taking into account the age group and the patient's preferences. In conclusion, overall CCB are neither better nor worse than conventional therapy, allowing for possible small differences in stroke and MI. The ACE inhibitors may protect better, although data are incomplete.
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PMID:Calcium channel blockers in hypertension: reappraisal after new trials and major meta-analyses. 1171 Jul 89

The objectives of treating hypertension are to achieve adequate control of blood pressure (BP) and maintain it under tight control. Maintenance of tight control of BP will most likely prevent stroke, heart attack, and heart failure, cause regression of left ventricular hypertrophy, and quite possibly preserve or improve renal function. The last two salutary effects combined will further reduce the morbidity and mortality in the treated hypertensive subjects. Choice of antihypertensive drugs is of significant importance so that our efforts to control hypertension do not grossly alter the quality of life. The cost of therapy is also an important consideration. Thus, thiazide diuretics, beta-blockers, and central inhibitors that are relatively inexpensive and adequately lower BP should be a common choice. However, if drowsiness interferes with work, or impotence becomes a threat for the marital partner or significant other, adjustment has to be made. The metabolic abnormalities consisting mainly of impaired glucose tolerance, hypercholesterolemia, and insulin resistance often induced by these relatively inexpensive drugs have put calcium channel blocker and ACE inhibitor group of drugs on the top of the list for antihypertensive therapy. They are far more expensive, yet offer no greater antihypertensive advantage than a diuretic or central inhibitor, except in special circumstances.
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PMID:Profiling Antihypertensive Therapy. 1185 Jul

Diabetes is now the leading cause of end-stage renal disease, blindness, lower-extremity amputations and impotence. In addition, the risk of death from cardiovascular disease such as myocardial infarction and stroke is more than doubled in diabetics. In September 2001, scientists from around the world met in Melbourne to discuss the mechanisms underlying neuronal and vascular changes in diabetic complications. This report summarizes the meeting and attempts to identify potential targets for drug intervention in diabetic complications. (c) 2001 Prous Science. All rights reserved.
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PMID:Targets to trials in diabetic complications. 1273 70

Over the past decade, national and international guidelines have proposed beta-blockers to be used on an equal footing with diuretics for initial therapy of hypertension. This preferred status was supposedly based on evidence documenting a reduction in morbidity and mortality with beta-blocker therapy in hypertension. We systematically analyzed all available outcome studies and found no evidence that beta-blocker based therapy, despite lowering blood pressure, reduced the risk of heart attacks or strokes. Despite the inefficacy of beta-blockers, the incidence of adverse effects is substantial. In the MRC study, for every heart attack or stroke prevented, three patients withdrew from atenolol because of impotence, and another seven withdrew because of fatigue. Thus the risk/benefit ratio of beta-blockers is characterized by lack of efficacy and multiple adverse effects. Given that many thorough, prospective, randomized trials attest to efficacy and safety of diuretics, calcium antagonists, ACE inhibitors, and angiotensin receptor inhibitors, the time has come to admit that beta-blockers should no longer be considered appropriate for first-line therapy in uncomplicated hypertension.
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PMID:beta-Blockers in hypertension-the emperor has no clothes: an open letter to present and prospective drafters of new guidelines for the treatment of hypertension. 1455 68

Nitric oxide is a key intercellular messenger in the human and animal bodies. The identification of nitric oxide (NO) as the endothelium-derived relaxing factor (EDRF) has driven an enormous effort to further elucidate the chemistry, biology and therapeutic actions of this important molecule. It has found that nitric oxide is involved in many disease states such as such as chronic heart failure, stroke, impotent (erectile dysfunction). The bioactivity of nitric oxide intrinsically linked to its diffusion from its site production to the sites of action. Accurate reliable in real time detection of NO in various biological systems is therefore crucial to understanding its biological role. However, the instability of NO in aqueous solution and its high reactivity with other molecules can cause difficulties for its measurement depending on the detection method employed. Although a variety of methods have been described to measure NO in aqueous environments, it is now generally accepted that electrochemical (amperometric) detection using NO-specific electrodes is the most reliable and sensitive technique available for real-time in situ detection of NO. In 1992 the first commercial NO electrode-based amperometric detection system was developed by WPI. The system has been used successfully for a number of years in a wide range of research applications, both in vitro and in vivo. Recently, many new electrochemical nitric sensors have been invented and commercialized. Here we describe some of the background principles in NO sensors design, methodology and their applications.
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PMID:Real time and in vivo monitoring of nitric oxide by electrochemical sensors--from dream to reality. 1535 68


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