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

In order to investigate the vasopressor role of ADH in the regulation of blood pressure, passive immunization experiments with an antibody to AVP were carried out in experimentally hypertensive rats. In hypertensive rats treated with deoxycorticosterone acetate (DOCA), spontaneously hypertensive rats (SHR) and spontaneously hypertensive stroke-prone rats (SHR-sp), the intravenous injection of a specific vasopressin antibody resulted in a transient fall of blood pressure of 11 approximately 25mmHg, while in rats with two-kidney Goldblatt hypertension and normal rats, the blood pressure was not affected. This strongly suggests that ADH contributed to systemic vaso-constriction in DOCA hypertension and spontaneous hypertension in rats.
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PMID:[The vasopressor role of ADH in the maintenance of blood pressure in experimentally hypertensive rats (author's transl)]. 49 16

Seven chronically prepared dogs (electromagnetic flow transducers around the pulmonary and left renal artery, left atrial catheter) maintained on a controlled sodium and water intake were studied. About 20 h after the last intake of food and water, the effects of i.v. methohexitone (initial dose: 6.10 +/- 0.84 mg/kg bw; sustaining infusion: 0.34 +/- 0.10 mg/min.kg bw) on renal excretion of sodium, potassium, urea and water as well as on several haemodynamic values were investigated over a period of 60 min (MP) after a control period (CP) of 60 min in the unanaesthetized state. In 18 of 19 experiments water diuresis (U/Posm less than 1) was observed between 20 and 40 min after starting the administration of methohexitone. Urine volume increased from 44 +/- 21 microliter/min.kg bw (CP) to 104 +/- 62 microliter/min.kg bw (MP).I.v. administration of arginine-vasopressin (ADH) completely abolished water diuresis. During MP, there was a decrease in cardiac output (-11%), stroke volume (-36%) and left atrial pressure (-27%), heart rate increased (+ 43%). Mean arterial blood pressure and renal blood flow did not change. It is assumed-as plasma osmolality did not change-that the central release of antidiuretic hormone is suppressed by methohexitone.
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PMID:[Water diuresis during methohexitone anaesthesia. Studies in chronically instrumented dogs (author's transl)]. 65 67

A patient, 38-year-old man, with hemorrhage into a prolactin-secreting pituitary adenoma, or pituitary apoplexy, is reported. On his admission, clinical examinations revealed typical stigmata indicating that he suffered from an acute attack of pituitary apoplexy probably induced by acute meningitis. He survived the acute attack and recovered spontaneously without an urgent operation. Although there was no suspicious sign and symptom of hypopituitarism, the first study performed immediately after the attack suggested strongly that hypopituitarism might acutely developed during the hemorrhage into the tumor. Moreover, the follow-up studies indicated that TSH, LH and ADH recovered spontaneously from the initial damage following the resorption of hemorrhage for the next 3 months.
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PMID:A case of pituitary apoplexy with spontaneous recovery. 68 74

Cases which present abnormality in water-electrolyte before and after operation of pituitary adenoma are occasionally reported. The authors have encountered a case in which neurological symptoms became aggravated abruptly with pituitary apoplexy after admission, hyponatremia was noted before operation and polyuria, not hypotonic urine was observed after operation. As a result of an endocrinological examination which may have an influence on water-electrolyte (ADH, aldosterone, ANP, etc.) the ADH level in hyponatremia before operation was high at 6.8 pg/ml; so, it was taken as SIADH. According to a study at the time of polyuria after operation, the ADH level was normal at 2.4 pg/ml, the ANP level was abnormally high at 140 pg/ml and the specific gravity of the urine was kept at 1.010 or more. So, polyuria was considered due to abnormally increased content of serum ANP. In polyuria due to abnormally increased content of serum ANP, the osmotic pressure of the urine is maintained relatively well, which is a clinical feature evidently different from diabetes insipidus. After operation for pituitary adenoma, water-electrolyte should be controlled with polyuria due to abnormally increased content of serum ANP in addition to diabetes insipidus taken into consideration.
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PMID:[An interesting case of pituitary apoplexy showing abnormality in water-electrolyte before and after surgery]. 214 44

In 12 of 76 stroke patients complicated by the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), a significant increase in urinary prostaglandin E (PGE) (p less than 0.005), and a significant positive relationship between the plasma arginine vasopressin (AVR) level and urinary PGE excretion were observed (r = 0.72, p less than 0.05). The experimental results are consistent with the view that renal PGE acts as a modulator of ADH. Nowadays acetylsalicylic acid (ASA), an inhibitor of prostaglandin biosynthesis, is widely used in ischemic stroke, it was felt necessary to study the effect of this drug on urinary PGE excretion. Therefore various daily doses of ASA were given orally for 3 days to patients with ischemic stroke. PGE values in 24-hour urine samples were measured every day for 3 days before administration of the drug and for 3 days during ASA administration. In 10 patients who took 75 mg of ASA, the decrease in urinary PGE excretion was not statistically significant. On the other hand when ASA was administered 300 mg once in 19 patients or 300 mg 4 times in 11 cases, urinary PGE excretion decreased significantly (p less than 0.05 and p less than 0.05 respectively). In another group of 8 patients who were observed before, during and after the ASA administration, a daily oral dose of 300 mg for 3 days caused a significant decrease in urinary PGE excretion during these 3 days (p less than 0.05). The urinary PGE excretion returned to the control level within 3 days after cessation of the ASA administration.
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PMID:Effect of acetylsalicylic acid on urinary excretion of prostaglandin E in stroke patients. 356 67

Congestive heart failure is associated with ventricular hypertrophy and dilatation, increased circulating catecholamines, and peripheral vasoconstriction. The extent to which these changes occur, whether they are a favorable "compensatory mechanism" or contribute to cardiocirculatory dysfunction, depends on the cause and severity of the heart failure. The addition of new sarcomeres through ventricular hypertrophy distributes the excess workload of the failing ventricle over more contractile units. In ventricular pressure overload, hypertrophy primarily increases wall thickness and ventricular volume is not usually increased; the converse is true with ventricular volume overload. Hypertrophy can result in enhanced or depressed contractile performance, depending on the stimulus for hypertrophy and method by which contractility is evaluated. The "ventricular function curve," which relates stroke volume to ventricular filling pressure or volume, overestimates the role played by the "Starling principle" as a compensatory mechanism and underestimates how well contractile performance is preserved. The evaluation of end systolic pressure-volume relationships under conditions of variable afterload closely reflects the isometric length-tension relationship and is therefore a more accurate way to quantitate cardiac muscle performance. Pressure overload hypertrophy usually leads to a depression in contractility whereas volume overload may not. An exaggerated sympathoadrenal response is another hallmark of severe heart failure that enhances contractility, helps initiate hypertrophy, and maintains arterial perfusion pressure. A generalized increase in peripheral vascular resistance occurs and is most prominent in those circulations most susceptible to neurohumoral control (renal, splanchnic, cutaneous). This favors perfusion of the cerebral and coronary circulations. Vasoconstriction is further enhanced by the activation of the renin-angiotensin-aldosterone system and secretion of ADH. This results in sodium retention and plasma volume expansion. In early mild heart failure, vasomotor tone may be normal at rest; however, the sympathoadrenal response to exercise may be intense. Moderate alpha receptor stimulation reduces skeletal muscle blood supply and favors the intramuscular redistribution of blood flow from inactive to active muscle fibers, thereby maintaining a normal oxygen consumption. During the later stages of heart failure, increased vascular stiffness due to increased sodium content and excessive norepinephrine appears to restrict nutritional blood flow to exercising muscle at the conductance-vessel level. Vasodilator drugs may reduce aortic impedance and improve cardiac output, may lower ventricular filling pressure, and relieve congestive symptoms, and may result in complex but favorable changes in the distribution of blood flow to the regional circulations.
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PMID:Cardiocirculatory dynamics in the normal and failing heart. 645 90

The mechanisms by which elevated levels of vasopressin (ADH) in man and animals cause serious myocardial dysfunction, evidenced by arrhythmias, reduction in cardiac output and coronary blood flow, are not settled. Experiments were conducted in 16 isolated working left ventricles to examine their metabolic and hemodynamic responses to the infusion of vasopressin and the combination of vasopressin and epinephrine. Contractile performance was evaluated by analysis of positive dP/dt, contractile element velocities, and ventricular work-curves using stroke work/end-diastolic pressure. Relaxation parameters, including negative dP/dt and the early diastolic relaxation time constant, were also studied. Coronary blood flow was reduced 22% or less by vasopressin while cardiac output was maintained at a constant level. Myocardial oxygen consumption, lactate and potassium balances were determined from arterial and coronary sinus concentrations. Vasopressin produced myocardial dysfunction indicated by decrements in contractile and relaxation indices, without evidence of global ischemia. Epinephrine restored the mechanical performance to normal without significant change in coronary blood flow, myocardial oxygen consumption, or lactate and potassium balance.
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PMID:Mechanisms of impaired cardiac function by vasopressin. 736 15

To determine the influence of hydration state upon circulatory controls, we studied four relatively fit subjects during duplicate 30-min cycle ergometer exercise bouts (55% VO2max) in euhydrated, hypohydrated, and hyperhydrated conditions. Ambient temperature was 35 degrees C. Hypohydration was achieved by 4 days of diuretic administration and resulted in a whole-body weight loss of 2.2 kg and a plasma volume decrease of approximately 700 ml. Hyperhydration was achieved by ADH administration plus ingestion of 2 liters water but caused only a minor increase volume. Hypohydration resulted in a significantly reduced cardiac output during exercise; this the result of a reduction in stroke volume of 17 ml.beat-1 without adequate elevation in heart rate. the internal temperature (Tes) threshold for cutaneous vasodilation was elevated by 0.42 degree C in hypohydrated conditions; but once vasodilation occurred, the slope of the arm blood flow:Tes relation was unchanged from control. Maximal arm blood flow was reduced by nearly 50% in hypohydration. These restrictions in cutaneous blood flow served to maintain an already compromised venous return, but due to the limitation of core-to-skin heat transfer, forced Tes to nearly 39 degrees C, significantly higher than in euhydrated conditions.
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PMID:Effect of hydration state of circulatory and thermal regulations. 744 Feb 85

We report an 82-year-old retired man who developed syndrome of inappropriate secretion of ADH (SIADH) caused by sodium valproate (VPA). He had been taking VPA for treatment of symptomatic epilepsy due to cardioembolic stroke. Although he was clinically asymptomatic, he was found to have decreased level of serum sodium concentration (128 mEq/l). Association of hyponatremia, normal urinary sodium concentration, high urine osmolality and increased concentration of serum ADH strongly suggested the presence of SIADH. There were no underlying disorders which can cause SIADH, such as malignant neoplasm with autonomous ADH release, non-malignant pulmonary diseases and active disorders of the central nervous system. Eight days after discontinuation of VPA administration serum sodium level increased (142 mEq/l) to the normal level. Then, we started the administration of VPA again to confirm that VPA was responsible for developing hyponatremia. As a result, he developed SIADH with hyponatremia (128 mEq/l) again, which improved after discontinuation of the administration. Therefore, we concluded that the SIADH might have been caused by administration of VPA. This is the first report on adverse effect of VPA causing SIADH.
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PMID:[Valproate related syndrome of inappropriate secretion of antidiuretic hormone (SIADH)--a case report]. 782 Sep 67

Hemodynamic and hormonal responses to lower body negative pressure (LBNP) after 12-h head-down tilt (HDT) were examined to investigate the mechanism of orthostatic intolerance following spaceflight. Ten young healthy male volunteers participated in the experiment. After 6 degrees HDT for 12 h, the tolerance to 1 h continuous -30 mm Hg LBNP was tested. Variables were measured before and after HDT, during LBNP, and 1 and 10 min after LBNP. Significant reduction in leg volume and plasma volume were observed at the end of 12-h HDT (500 ml and 5.5%, respectively). In the tolerant group, stroke volume index (SI) was decreased by 35% after 15 min LBNP, and carotid arterial blood flow (CBF), by 27% at the end of LBNP compared to the pre-LBNP value. Of the 10 subjects, 5 developed presyncope during LBNP; they exhibited remarkable reduction in SI, CBF, and heart rate, and increased secretion of ADH and adrenaline during or just prior to presyncope. This non-tolerant group tended to be hemo-concentrated from the start of the experiment. However, it will require a prospective study to determine if this variable is a reliable predictor of the outcome of the post-HDT LBNP test from data collected at the end of HDT.
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PMID:Hemodynamic and hormonal correlates with exposure to lower body negative pressure after 12 hours head-down tilt. 835 12


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