Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Orthostatic dysregulation (OD), originally a German-Scandinavian term partially corresponding to an Anglo-American concept of sympathotonic orthostatic hypotension, is characterised by altered cardiovascular control on standing, and its clinical features include dizziness, palpitation and, occasionally, orthostatic hypotension. The symptomatology suggests presence of cardiovascular adrenoceptor dysfunction, although the aetiology of OD has not been elucidated. The above situation prompted us to investigate autonomic nervous function in OD. The subjects were 8 patients with OD (20 +/- 2 years old; mean +/- SD), all of them fulfilled the diagnostic criteria accepted in Japan, and 6 healthy controls (17 +/- 3 years old). Noradrenaline and isoproterenol infusion tests and conventional haemodynamic functional tests (70 degrees passive head-up tilt, cold pressor test, Valsalva manoeuvre and Aschner's eye-ball pressure test) were carried out upon the subjects under the continuous measurement of blood pressure, pulse rate and respiration. Plasma vasoactive substances (noradrenaline, adrenaline, arginine-vasopressin and renin activity) were also determined in supine position and at 15 minutes after the 70 degrees passive head-up tilt. In noradrenaline infusion test, different doses (0.01 microgram/kg, 0.02 microgram/kg, 0.05 microgram/kg and 0.1 microgram/kg) of noradrenaline were administered by means of intravenous bolus injection, and a degree of subsequent rise in blood pressure was used as an index for the cardiovascular alpha-adrenoceptor sensitivity. In isoproterenol infusion tests cardiovascular beta 1- and beta 2-adrenoceptor sensitivities were assessed, respectively, by a degree of an increase in pulse rate and a degree of a fall in blood pressure following bolus injection of the drug (0.001 microgram/kg, 0.002 microgram/kg, 0.005 microgram/kg and 0.01 microgram/kg).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Cardiovascular alpha- and beta-adrenoceptor sensitivities in orthostatic dysregulation]. 216 87

A 15-year-old boy with diarrhea, dizziness, dysesthesias, and depression is described. On admission, his blood pressure was 110/84 reclining but less than 40 systolic while standing. Vibratory sensation and nerve conduction velocities were decreased in his lower extremities. CSF protein concentration was normal but sural nerve biopsy demonstrated generalized demyelination. Extensive toxicologic and metabolic screening proved unremarkable. Norepinephrine concentrations in plasma and urine, and CSF concentration of 3-methoxy-4-hydroxy phenylglycol (MHPG) were markedly reduced. The patient demonstrates a combination of autonomic dysfunction, peripheral neuropathy, and affective disorder. This collection of clinical and neurochemical findings represents a previously unreported entity involving a defect of both central and peripheral noradrenergic systems.
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PMID:Autonomic dysfunction, peripheral neuropathy, and depression. 285 34

Orthostatic intolerance (OI) syndromes are frequent and share symptoms like dizziness and orthostatic syncope. Their pathophysiology however seems to be different. The aim of our work was to evaluate autonomic and hemodynamic behaviour in patients with familial amyloidotic polyneuropathy and neurally mediated syncope in supine position and after acute orthostatic passive stress. We studied 12 patients with autonomic failure (group A), 12 patients with neurally mediated syncope (group B) and 16 aged matched normal controls (group C), in supine position and during the first 10 min of head-up tilt test (HUTT). Beat-by-beat blood pressure and heart rate were continuously monitored and digitised at 500 Hz. The baroreceptor alfa-index gain (vagal reflex-BRG), high frequency of RR variability (HFRR, vagal tonus) and low frequency of systolic arterial pressure variability (LFSAP, sympathetic tone) were calculated. Catecholamines, plasma brain (BNP) and atrial natriuretic (ANP) peptides were also measured. Hemodynamic data were derived and calculated by the non-invasive modelflow method. During supine position, cardiac output (CO) and stroke volume (SV) were similar in all groups. Mean arterial pressure (MAP) and BNP were higher in group A. Noradrenaline (NOR), BRG, HFRR and LFSAP were extremely low in this group. BRG and adrenaline (ADR) were higher in group B than in controls. Within the first 10 min of HUTT, there was a huge drop of CO, SV and MAP in group A, maintenance of very low levels of neurohormones and lack of autonomic function. HR, LFSAP and ADR had a higher rise at HUTT in group B compared with controls (p<0.01) but a significant decrease of BRG was noted (p<0.05). ANP or BNP did not change with tilt in any group. Different orthostatic intolerance syndromes may show important hormonal, autonomic and hemodynamic differences during supine rest and enhanced after passive orthostatism.
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PMID:Hemodynamic, autonomic and neurohormonal behaviour of familial amyloidotic polyneuropathy and neurally mediated syncope patients during supine and orthostatic stress. 1684 44