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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Amezinium metilsulfate is a new, indirectly acting sympathomimetic drug which exclusively affects postganglionic sympathetic neurons and inhibits both intraneuronal monoamine oxidase and norepinephrine reuptake. We examined the short-term effects of amezinium in five patients with severe neurogenic orthostatic hypotension. Single-dose administration of amezinium (10 mg) raised both the supine and sitting mean blood pressures by 15 to 45 mm Hg for 8 hours, with a slight increase in the plasma norepinephrine level. Repeated administration of amezinium (10 to 40 mg/d) produced an increase in sitting blood pressure in three patients and improvement of the orthostatic symptoms in all patients without remarkable recumbent hypertension. The heart rate was increased in two patients. The results indicate that amezinium is of therapeutic value for the treatment of neurogenic orthostatic hypotension. The adrenergic effect of amezinium on the blood pressure and heart rate apparently was related to a slight increase in endogenous norepinephrine in the presence of alpha- and beta-adrenoreceptor supersensitivity.
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PMID:Treatment of neurogenic orthostatic hypotension with amezinium metilsulfate, a new indirect sympathomimetic drug. 338 28

Questions concerning the proper management of hypertension in surgical patients often arise in primary care practice. Currently available literature and our own clinical experience lead us to make the following recommendations. 1. Continue antihypertensive therapy up to and including the morning of surgery, when the dose should be given with a small sip of water. 2. If possible, adjust antihypertensive therapy so blood pressure is less than 160/90 mm Hg for at least two weeks prior to surgery. 3. Discontinue all monoamine oxidase inhibitors at least one week prior to surgery and substitute alternative antihypertensive or antidepressant medication as necessary. 4. Be attentive to the patient's preoperative volume status and any evidence of cardiovascular disease. 5. In patients with postoperative hypertension, search for specific aggravating factors and treat them primarily. 6. Discuss with the anesthesiologist any difficulties in blood pressure control.
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PMID:Perioperative hypertension. The primary care physician's role. 339 67

The effect of an acute i.v. infusion of noradrenaline (NA) on regional cerebral blood flow (rCBF) was investigated in the awake rat using [14C]iodoantipyrine as diffusible tracer. The contribution of vascular monoamine oxidase (MAO) to the efficiency of the enzymatic blood-brain barrier (BBB) to catecholamines was assessed by measuring the multiregional cerebrovascular response to circulating NA given alone or after i.v. administration of the monoamine oxidase inhibitor, clorgyline. Since i.v. infusion of NA elevates blood pressure, the influence of NA on the cerebrovascular bed was first studied by determining the relationship between rCBF and the mean arterial pressure (MAP). When the MAP was only slightly increased (to approximately 130 mm Hg), a trend to flow decrease under NA infusion was observed. Secondly, we compared the effects of NA on rCBF in animals treated or not treated with clorgyline. This was performed under moderate hypertension (within the 'autoregulated' range of MAP) to avoid any risk of mechanical damage to the BBB. Clorgyline administration alone did not significantly modify rCBF, but the subsequent i.v. infusion of NA induced an increase in rCBF (weighted mean 14%) in all structures investigated. The differences being statistically significant (P less than 0.05) in 5 out of 13 structures by up to 20%. Compared to studies involving disruption of the morphological BBB in which plasma NA elicits a widespread important increase in blood flow, the weak cerebrovascular effects we observed provide indirect evidence for the efficiency of the BBB to catecholamines in the conscious rat within the autoregulated range of arterial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of monoamine oxidase inhibition on the regional cerebral blood flow response to circulating noradrenaline. 340 3

This study on the role of the sympathetic nervous system in the development of hypertension involves the measurement of dopamine and norepinephrine accumulation in various tissues of the hypertensive and random-bred normotensive strains of mice at basal levels, and following a pargyline-L-dopa treatment. Under such a treatment, designed to suppress the homeostatic action of monoamine oxidase and to better expose the relationship between dopamine and norepinephrine, the brain and heart of the hypertensive mice accumulated more dopamine than the normotensive mice. There was a significantly lower norepinephrine accumulation in the heart of the hypertensive mice in spite of comparable dopamine-beta-hydroxylase activity in this tissue between the two strains of mice. Under the pargyline-L-dopa treatment, the brain and heart of the older mice in both hypertensive and normotensive strains accumulated significantly (p less than 0.05) more dopamine than those of their younger counterparts, while their norepinephrine accumulation remained unchanged. The results demonstrated different patterns of response of dopamine and norepinephrine in the development of hypertension.
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PMID:L-dopa metabolism in genetically hypertensive mice: effect of pargyline. 344 95

Anxiety is the fifth most common clinical diagnosis in the primary care setting. Panic disorder, a severe episodic form of anxiety, has been found to occur in approximately 6% of primary care patients. These patients often selectively focus on one of the frightening autonomic symptoms and are frequently misdiagnosed. The three most common presentations of panic disorder in the medical setting are cardiac symptoms (chest pain, tachycardia), neurologic symptoms (headache, dizziness/vertigo, syncope), and gastrointestinal symptoms, especially epigastric distress. The presentation of cardiac symptoms by patients with panic disorder is especially likely to lead to expensive and potentially iatrogenic medical testing. Hypertension and peptic ulcer are the most commonly associated medical diagnoses in patients with panic disorder. Major depression, alcohol abuse, simple phobias, and posttraumatic stress disorder are the most frequently associated psychiatric diagnoses. Psychopharmacologic treatment of panic disorder has been demonstrated to be highly effective in double-blind, placebo-controlled studies. Effective psychopharmacologic agents include the tricyclic antidepressants (notably imipramine and desipramine), the monoamine oxidase inhibitors (phenelzine), and the high-potency benzodiazepines (alprazolam).
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PMID:Panic disorder: epidemiology, diagnosis, and treatment in primary care. 353 Nov 89

A young woman taking tranylcypromine for depression was hospitalized with severe chest pain and hypertension after eating cheese. Electrocardiography initially showed arrhythmias and precordial ST segment depression. Myocardial creatine kinase values were elevated, and echocardiography showed regional ventricular dysfunction, suggestive of focal cardiac myonecrosis. The cardiovascular pathophysiology of tyramine hypertensive crisis and related catecholamine excess states, including pheochromocytoma and clonidine withdrawal, is reviewed. Cardiac myonecrosis is a potential adverse effect of the hypertensive crisis associated with monoamine oxidase inhibitor use. Psychiatric indications for monoamine oxidase inhibitors may be expanding, but clinicians should continue to exercise caution in the use of these agents.
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PMID:Cardiac myonecrosis in hypertensive crisis associated with monoamine oxidase inhibitor therapy. 357 43

Using a radioenzymatic assay, placental monoamine oxidase (MAO) activity was measured at term after delivery in normal and high-risk pregnancies where decreases in placental blood flow previously were shown. MAO activity in placentas of healthy controls after spontaneous labor was similar to that after elective cesarean section not in labor (mean +/- SE, 133 +/- 18 versus 100 +/- 15 nmol/min/mg protein, respectively). Compared to controls, there was a significant reduction in placental MAO activity in high-risk pregnancies (chronic hypertension, toxemia, and diabetes mellitus), 71 +/- 14, 69 +/- 22, and 69 +/- 7, respectively (P less than 0.05). These differences also were maintained when data were expressed per total placental weight. Effects of antihypertensive drugs on MAO activity in healthy placental tissue were assessed. In homogenates, both hydralazine and magnesium sulfate reduced enzyme activity, while in explants this was not observed. The effects of certain metabolites (which are elevated in plasma of diabetic patients) on healthy homogenates also were studied. Only butyrate reduced enzyme activity. In conclusion, placental MAO activity in vitro is low in term high-risk pregnancies. This may reduce local metabolic inactivation of catecholamines and serotonin and consequently lead to a decrease in blood flow. Such a direct relationship must be confirmed in further studies.
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PMID:Monoamine oxidase activity in the term human placenta. 371 43

New England Deaconess Hospital rats implanted with a pheochromocytoma P259 became hypertensive and showed high concentrations of plasma dopamine (42.0 +/- 14.6 ng/ml) and norepinephrine (45.7 +/- 8.4 ng/ml). However, the norepinephrine content of several peripheral tissues of these rats did not differ from those of the New England Deaconess Hospital control rats, and their dopamine content, although slightly higher, was much lower than would have been expected from the plasma dopamine levels. Methylation by catechol-O-methyltransferase did not appear to play a major role in the inactivation of tissue catecholamines since there were no noticeable increases of normetanephrine or 3-methoxytyramine in the tissues of the rats with pheochromocytoma. There was also no increase in conjugated dopamine, in either the sulfate or glucuronide form, in the plasma or tissue of the hypertensive rats, although injection of L-dopa induced a large increase in dopamine sulfate in the plasma and urine of these rats. This finding indicated that, although their sulfoconjugation mechanism was intact and not affected by the pheochromocytoma, it did not participate in the metabolism of dopamine released by the tumor into the blood. On the other hand, plasma and urine of tumor-bearing rats exhibited abnormally high concentrations of homovanillic acid, the main metabolite of dopamine resulting from monoamine oxidase action. In contrast to the control rats, intravenous infusion of free dopamine in rats with pheochromocytoma had no effect on plasma free dopamine levels but increased homovanillic acid levels considerably. The present data underline the important role of monoamine oxidase in the removal of excessive quantities of catecholamines released by the tumor in New England Deaconess Hospital rats with the pheochromocytoma implant.
Hypertension 1986 Oct
PMID:Metabolism and storage of catecholamines in rats with pheochromocytoma implants. 375 28

The effects of sino-aortic denervation (SAD) on cardiac noradrenaline stores, turnover and neuronal re-uptake were examined in normotensive rabbits and rabbits with two-kidney, two wrapped hypertension. Ten to 12 days after SAD, left ventricular (LV) noradrenaline stores were reduced in renal hypertensives to 43% of that of the sham-operated rabbits, although there was no overt evidence of heart failure. This did not occur after SAD of normotensive rabbits. The reduction in noradrenaline content was accompanied by a reduction in [3H]-noradrenaline turnover time (4.4 h) compared with renal hypertensive (7.4 h) and the normotensive subgroups (9.3 h). Noradrenaline turnover rates were elevated by 25% in hypertensive compared with normotensive rabbits. Left ventricular tyrosine hydroxylase, dopamine-beta-hydroxylase and type A monoamine oxidase activities were similar in normotensive and hypertensive rabbits and were unaffected by SAD. Following SAD of hypertensive rabbits cardiac neuronal uptake for alpha-methylnoradrenaline was reduced by 33% compared with either the hypertensive or the normotensive rabbits. Sino-aortic denervation did not affect neuronal uptake in normotensives. These results suggest that following SAD of hypertensive rabbits, cardiac noradrenaline stores are depleted by enhanced cardiac sympathetic activity (reduction in [3H]-noradrenaline turnover time) and a reduction in neuronal re-uptake. It appears that the hypertensive hypertrophied heart is less able to tolerate chronic sympathetic overactivity and/or liability in coronary oxygen supply brought about by SAD.
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PMID:Differential effects of sino-aortic denervations on cardiac noradrenaline stores, turnover and neuronal re-uptake in normotensive and renal hypertensive rabbits. 377 95

A total of 127 patients with bronchial asthma of infectious-allergic genesis and chronic obstructive bronchitis were examined for the central and regional hemodynamics as well as for the blood levels of serotonin and monoamine oxidase. The combination of chronic bronchial obstruction with stable "pulmogenic" arterial hypertension was associated with a significantly decreased cardiac index, a reduction in the pulse blood filling of the brain as well as an increase in the peripheral vascular resistance, the pressure in the pulmonary artery, serotonin levels and monoamine oxidase activity. A multiple modality therapy (hydralazin, talinolol, hydrochlorothiazide) elicited an improvement of the hemodynamic and normalization of the biochemical parameters.
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PMID:[Arterial hypertension in chronic bronchial obstruction and various problems of its treatment]. 384 Feb 15


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