Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.11.18 (MAP)
 7,412 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to determine factors contributing to sodium induced changes of blood pressure, 20 patients with essential hypertension were studied when on their regular sodium intake and after two weeks of a low sodium diet (50 mmol daily) and two weeks of a high sodium diet (300 mmol daily). There were two periods of regular sodium intake, one of four weeks at the beginning and one of two weeks at the end of the study. The change in mean arterial pressure between the high and low salt diets (delta MAP) was regarded as a measure of sodium sensitivity, and was directly correlated with age and initial blood pressure. Compared with non-responders, responders (delta MAP 10 mmHg or more) showed a lesser activation of the renin-angiotensin-aldosterone system during the low salt period. The response to the administration of intravenous frusemide was not helpful in predicting sodium sensitivity. A significant but relatively small (4.2 mmHg) reduction in MAP was obtained during low salt period compared with the first period of regular sodium intake. The data suggest that moderate dietary sodium restriction can help to reduce the blood pressure of the relatively older patient with hypertension.
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PMID:Sodium sensitivity in essential hypertension: role of the renin-angiotensin-aldosterone system and predictive value of an intravenous frusemide test. 653 May 38

Vascular instability represents the most frequent intradialytic complication of uremic patients. Catecholamine impairment, changes in plasma sodium or osmolality and, more recently, temperature (T) of dialysate have been proposed to explain this phenomenon. In order to evaluate the role of T in hemodynamic stability, we studied the effect of cooling dialysate in 5 patients (3 m, 2 f), who often experienced hypotension during dialytic sessions. Dialysate T was lowered, leading to a body T decrease of 1.5 degrees C, measured by a thermistor in the pulmonary artery. Ultrafiltration was kept constant during both "warm" (W) and "cold" (C) hemodialysis (HD). Systemic and pulmonary hemodynamic parameters were studied by thermodilution technique. The evaluation was performed in the same patients during W-HD and C-HD with the same dialysate composition. MAP showed a significant reduction during the first hour under both dialysis conditions. Subsequently a further decrease of MAP was observed in W-HD, while it remained stable in C-HD. CI and SI demonstrated similar trends, whereas HR showed no major changes. TPRI appeared significantly higher during C-HD compared to W-HD, with no clinical symptoms of hypotension. Similarly pulmonary parameters resulted in a better cardiovascular stability during C-HD. Our hemodynamic study confirms the important role played by T on intradialytic vascular stability and may explain the better control observed during hemofiltration compared to standard W-HD.
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PMID:Cold as cardiovascular stabilizing factor in hemodialysis: hemodynamic evaluation. 667 15

In 74 chronic glomerulonephritis (CGN) and 13 hemodialysis patients (HD) blood volume and hemodynamic indices were examined. Significant correlation was observed between MPA and PV in CGN. High PV in high S-Cr group is considered to be correlated with anemia. Salt restriction reduced MAP without the change in BV in the impaired kidney function group in CGN. Volume depletion in HD shifted TPRI to lower level in the group with significant MAP reduction. The results indicate that sodium rather than water will play an important role in this type of hypertension.
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PMID:Hypertension in chronic glomerulonephritis. 675 Jan 90

Baroreflex activity is a determinant of the homeostatic response to alteration in blood pressure. We examined the factors that determine the magnitude of the vasodepressor response to sequential incremental intravenous infusions of sodium nitroprusside (NP), 0.05 to 6.4 micrograms/kg/min, in eight male patients with essential hypertension. Each infusion level was of 10 minutes' duration. Change from control values of mean arterial pressure (delta MAP), heart rate (delta HR) and plasma norepinephrine (delta NE) were obtained at the end of each infusion level. Significant correlations were found between delta MAP vs log dose NP, delta HR vs delta MAP and delta NE vs delta MAP for each patient (p less than 0.05). However, the slopes of these relationships varied widely between subjects and were significantly correlated with the control blood pressure of each patient. In addition, the sympathetic responsiveness, as measured by delta NE vs delta MAP, was inversely correlated with the degree of vasodepressor response seen. Thus, the magnitude of the vasodepressor response was determined by two major factors: 1) the predrug blood pressure, possibly reflecting altered vascular geometry with hypertension; 2) the degree of sympathetic response, which probably acts by mediating the degree of reflex alpha-adrenergic-mediated arteriolar vasoconstriction.
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PMID:Baroreflex sensitivity modulates vasodepressor response to nitroprusside. 684 71

The hypertension immediately after open heart surgery for coronary heart disease was chosen to evaluate the suitability of computer-controlled infusion sodium nitroprusside, to improve the circulatory state in heart failure by reducing the impedance to the left ventricular ejection. Sodium nitroprusside produced a prompt reduction of MAP to a preset level and a rise in cardiac index from an average of 2.1 +/- 0.3 to 2.4 +/- 0.4 when infused alone and to 3.1 +/- 0.5 1/min m2 (p less than 0.05, + 48%) after volume was infused to maintain LAP at a constant level to eliminate the effects of preload. The rise in cardiac index was associated with marked decrease in systemic vascular resistance from 2260 +/- 530 to 1415 +/- 280 and 1130 +/- 1130 +/- 270 dyns (p less than 0.005, 63%) respectively. The initial values of SVR correlated well with the fall of SVR (r = 0.78). Our results suggest that systemic vascular resistance is a strong indicator of the vascular responsiveness to vasodilation, the computer-controlled infusion of sodium-nitroprusside being suitable for the "titration" of the high systemic vascular resistance.
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PMID:[Hemodynamic effects of computer-guided blood pressure-lowering with nitroprusside sodium during the postoperative phase after aortocoronary bypass operations]. 698 28

In a prospective, double-blind, intraindividual, cross-over, placebo-controlled multicenter study, clinical and biochemical effects of once daily postprandial dose regimens of 50, 100, and 200 mg spironolactone were investigated in 45 outpatients with primary hypertension, WHO (World Health Organization) Stage I-II. Each of the three active therapy periods, which were randomly allocated to patients, were of 2 months' duration, with intervening placebo periods, Clinical and biochemical parameters, including furosemide-stimulated plasma renin activity (PRA), were recorded at regular intervals. All three spironolactone doses resulted in statistically significant blood pressure (BP) reductions independent of initial pretreatment levels and yielded satisfactory BP control in more than half of the patients. The 200 mg daily dose of spironolactone was found to be more effective than 50 but not 100 mg. When, correlating blood pressure response (delta MAP) to PRA, the profiling for positive spironolactone responders was characterized by high age and low PRA, irrespective of sex. Spironolactone therapy resulted in decreased serum sodium and magnesium values; potassium, creatinine, urate, and triglyceride levels were increased. However, all treatment values were within normal ranges. Side effects were infrequent and mainly of endocrine nature.
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PMID:Clinical and biochemical effects of spironolactone administered once daily in primary hypertension. Multicenter Sweden study. 699 72

1. To determine if increases in plasma sodium concentration P[Na] have any sustained effects of the renin-aldosterone system, P[Na] was increased in a group of six dogs over a period of 6 days by increasing sodium intake from 10 to 200 mmol per day while a fixed 700 ml per day water intake was maintained along with a continuous i.v. infusion of antidiuretic hormone (ADH) at a rate of 2.4 units per day. 2. P[Na] rose from 137.3 +/- 2.0 to 153.6 +/- 6.5 mmol/l during the high intake period. Plasma potassium concentration, 22Na space, and mean arterial pressure all remained near control levels in response to Na loading. 3. Plasma renin activity (PRA) averaged 1.0 +/- 0.1 ngAI/ml per hour on the final low Na day and fell transiently to 0.6 +/- 0.2 ngAI/ml per hour on the first day of sodium loading. For the duration of the study it remained at the control level. Plasma aldosterone concentration fell from the low Na level of 15.4 +/- 2.4 ng/100 ml to 10.5 +/- 1.5 ng/100 ml on the final day of high Na intake. 4. We conclude that increases in P[Na] in the absence of concomitant changes in P[K], 22Na space and MAP do not have a sustained effect on control of renin release but may exert a negative effect on aldosterone secretion.
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PMID:Effect of sustained hypernatraemia on the renin-aldosterone system in the dog. 701 64

This study evaluated the effect of prostaglandin (PG) on renal function in normal and deoxycorticosterone-acetate (DOCA) hypertensive Yucatan miniature swine. Eight animals were implanted with DOCA impregnated silicone strips. MAP increased in the conscious DOCA animals from a normal pressure of 110-115 mmHg, to 148 +/- 4 mmHg. After 3-4 weeks, the DOCA hypertensive and eight normal (sham or non-implanted) animals were anesthetized with sodium pentobarbital which reduced MAP in the DOCA pigs to normotensive levels. Under anesthesia, PG inhibition (indomethacin or meclofenamate, 2 mg/kg i.v.) increased MAP only in the normal group (P less than .05). PG inhibition caused a significant reduction in renal blood flow in both groups, but only decreased glomerular filtration rate in the DOCA animals (P less than .05). Radioactive microsphere distribution to the other cortex of the normal animals was significantly decreased with PG inhibition, (P less than .05). No consistent changes in electrolyte excretion or urine flow rate was seen in either group following PG inhibition. These data indicate that PG may influence renal hemodynamics in both normal and DOCA hypertensive Yucatan miniature swine. The finding that PG inhibition selectively decreases GFR in the DOCA animals suggests a possible protective role of these hormones in this hypertensive animal model.
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PMID:Effects of prostaglandin inhibition on renal function in deoxycorticosterone-acetate hypertensive Yucatan miniature swine. 732 8

Peritubular capillary hydrostatic and oncotic forces and their relationship to the renal excretion of sodium (UNaV) were examined in 19 patients with moderate and uncomplicated essential hypertension (HT) and compared with data from 20 normotensive subjects (NT). Observations were made in hydropenia (C) and during sustained isotonic saline volume expansion (E; 3% increase in body weight). The intrarenal venous pressure (IRVP) was used as an index of peritubular capillary hydrostatic pressure, and the efferent arteriolar colloid osmotic pressure (COPeff) was estimated from the arterial COP and the filtration fraction. C values (mean +/- SEM) in HT (and NT) were: arterial pressure (MAP) 110 +/- 3 mm Hg (85 +/- 1, p less than 0.001); glomerular filtration rate (GFR) 122 +/- 4 ml/min/1.73 m2 (128 +/- 3, p greater than 0.05); renal blood flow (RBF) 1172 +/- 38 ml/min/1.73 m2 (1298 +/- 48, p less than 0.05); IRVP 25.0 +/- 1.0 mm Hg (24.8 +/- 0.8, p greater than 0.05); COPeff 33.0 +/- 0.7 mm Hg (31.9 +/- 0.6, p greater than 0.05); and UNaV 140 +/- 13 mumole/min (161 +/- 12, p greater than 0.05). During E, the increase of UNaV in HT was more than double that of NT (p less than 0.001) while IRVP did not change in either group (p greater than 0.05); and COPeff fell by 26% (p less than 0.001) in both groups. GFR and RBF increased by 18% (p less than 0.001) and 19% (p less than 0.001) respectively, in HT, but did not change in NT. MAP remained unchanged in both groups. The results indicate that the peritubular capillary physical factors are normal in established essential hypertension, and that these forces are not involved in the exaggerated natriuretic response to volume expansion in essential hypertension.
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PMID:Renal sodium excretion and the peritubular capillary physical factors in essential hypertension. 746 93

Yeast cells can respond and adapt to osmotic stress. In our attempt to clarify the molecular mechanisms of cellular responses to osmotic stress, we cloned seven cDNAs for hyperosmolarity-responsive (HOR) genes from Saccharomyces cerevisiae by a differential screening method. Structural analysis of the clones revealed that those designated HOR1, HOR3, HOR4, HOR5 and HOR6 encoded glycerol-3-phosphate dehydrogenase (Gpd1p), glucokinase (Glk1p), hexose transporter (Hxt1p), heat-shock protein 12 (Hsp12p) and Na+, K+, Li(+)-ATPase (Ena1p), respectively. HOR2 and HOR7 corresponded to novel genes. Gpd1p is a key enzyme in the synthesis of glycerol, which is a major osmoprotectant in S. cerevisiae. Cloning of HOR1/GPD1 as a HOR gene indicates that the accumulation of glycerol in yeast cells under hyperosmotic stress is, at least in part, caused by an increase in the level of GPDH protein. We performed a series of Northern blot analyses using HOR cDNAs as probes and RNAs prepared from cells grown under various conditions and from various mutant cells. The results suggested that all the HOR genes are regulated by common signal transduction pathways. However, the fact that they exhibited certain distinct responses indicated that they might also be regulated by specific pathways in addition to the common pathways. Ca2+ seemed to be involved in the signaling systems. In addition, Hog1p, one of the MAP kinases in yeast, appeared to be involved in the regulation of expression of HOR genes, although its function seemed to be insufficient for the overall regulation of expression of these genes.
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PMID:Cloning and characterization of seven cDNAs for hyperosmolarity-responsive (HOR) genes of Saccharomyces cerevisiae. 750 Sep 33


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