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

The extracellular matrix of blood vessel walls contains elastin, collagen, and proteoglycans, all of which can affect vascular resistance and, hence, blood pressure by virtue of their biomechanical properties. In the present study, we have begun to explore the possibility that proteoglycans may play a role in the pathophysiology of hypertension by analyzing, qualitatively and quantitatively, the polysaccharide components of proteoglycans from aorta of two normotensive rat strains, Wistar Kyoto (WKY) and Wistar rats, and from spontaneously hypertensive (SH) rats of the Okamoto strain. The total concentration of aorta glycosaminoglycans in the SH rat was 33% higher than in the WKY rat, due to a 164% increase in chondroitin 4- and 6-sulfate. The content of dermatan sulfate (DS), hyaluronic acid (HA), and heparan sulfate (HS) was similar in the two strains. The 4-wk-old SH rat also had an increase in chondroitin sulfate (CS) compared to the 4-wk-old WKY rat, without any change in DS, HA, or HS. The Wistar rat had approximately the same concentration of CS und DS in the aorta as the WKY rat, but HS und HA were reduced by 62 and 37%, respectively. The galactosaminoglycans (CS and DS) were heterogeneous on cellulose acetate electrophoresis and exhibited a different pattern for each of the three strains. Undersulfated CS accounted for 15% of the total CS in WKY aorta but was present in only trace amounts in the SH aorta; 2% of the CS from the Wistar aorta was undersulfated. In all three strains, DS was exclusively 4-sulfated, and the CS contained approximately equal amounts of 4- and 6-sulfated galactosamine residues. Ultrastructural studies demonstrated that the HS was localized in the subendothelial matrix and the pericellular region surrounding the medial smooth muscle cells. CS and DS were primarily associated with collagen in the media. In the SH rat aorta the subendothelial matrix was thicker, and there was a relative increase in the CS/DS in the smooth muscle cell pericellular matrix. We suggest that, if similar alterations in CS proteoglycans are present in the resistance vessels, these changes may contribute to the increased peripheral vascular resistance in the hypertensive animal.
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PMID:Proteoglycans and hypertension. I. A biochemical and ultrastructural study of aorta glycosaminoglycans in spontaneously hypertensive rats. 372 Feb 75

Catecholamine sulfates were found to be inactive at vascular receptor sites. Only at one nonvascular receptor site important for blood pressure (BP) regulation was dopamine-3-O-sulfate found to be an inhibitory modulator of the adrenocortical secretion of aldosterone in vitro. However, sulfation of catecholamines (CA) does play an important role in BP regulation, as shown by the following observations: Sulfoconjugated CA with a long half-life are sometimes better markers of CA release than free CA, which have short half-lives. This is particularly true of dopamine (DA) sulfate because free DA, being rapidly sulfoconjugated, is usually undetectable. This led to the recognition of a previously unsuspected role of DA in paroxysmal hypertension and orthostatic hypotension. Measurements of CA sulfates reveal potentially important storage functions for sulfoconjugation that can rapidly inactivate excessive circulating free CA and so mitigate their cardiovascular impact while building up a pool of conjugated CA. The possibility that free CA can be generated from this pool through deconjugation whenever a need for them arises should be further investigated. Reproducible individual differences in the velocity of the sulfoconjugation of infused free CA can be detected, which suggests a genetic control of certain components of the sulfoconjugating process. These differences in sulfoconjugation probably modulate the cardiovascular action of CA and of some drugs with similar structure that also undergo sulfoconjugation.
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PMID:Role of sulfate conjugation of catecholamines in blood pressure regulation. 372 Sep 64

The effect of hypertension in pregnant women on fetal maturation is an issue of considerable importance. Because of a possible role of prolactin in fetal adrenal steroidogenesis and in fetal lung maturation, we have investigated the relationship between hypertension in pregnant women and levels of prolactin and dehydroepiandrosterone sulfate in serum of newborn infants. It was found that with the mild-to-moderate form of pregnancy-induced hypertension (PIH), there was little effect on prolactin levels in newborn serum. In newborns of women with severe PIH, however, serum prolactin levels were significantly greater (p less than 0.01) than those in newborns of women with uncomplicated pregnancies. Conversely, umbilical serum concentrations of dehydroepiandrosterone sulfate in newborns of women with severe PIH were significantly less (p less than 0.05) than those in newborns of women with uncomplicated pregnancies. These findings are supportive of the view that pituitary function and adrenocortical function of fetuses of women with PIH are different from those of fetuses of normotensive women. These findings are suggestive that PIH alters the function of the fetal pituitary and adrenal cortex.
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PMID:Prolactin levels in umbilical cord serum and its relation to fetal adrenal activity in newborns of women with pregnancy-induced hypertension. 374 60

The concentrations of unconjugated plasma dopamine (PDA) were studied in patients with various types of hypertension. Catecholamines were extracted from plasma specimens (1.0-3.0 ml) through an Amberlite CG50 (Li+-form) microcolumn and eluted by a magnesium sulfate - ethanol solution. The elute was then desalinated and deproteinized by the ethanol-treated precipitation procedure and dried in a vacuum oven at 25 degrees C. A fraction of catecholamines was assayed with the modified procedures of the COMT-mediated radio-enzymatic method. This assay system was sensitive enough to permit an accurate measurement of PDA as low as 6.0 pg per ml of plasma without any detectable contamination of the conjugated dopamine. The resting levels of PDA were 10.1 +/- 1.0 pg/ml (mean +/- SEM), 9.5 +/- 1.0 and 13.7 +/- 0.6 in patients with borderline hypertension (BH, n = 25), essential hypertension (EH, n = 22) and renovascular hypertension (RVH, n = 8), respectively. The values in EH patients were significantly smaller than those in age-matched normal controls (13.0 +/- 1.4, n = 14, p less than 0.05). Remarkably increased PDA values were observed in patients with pheochromocytoma (76.5 +/- 25.4, n = 9, p less than 0.01). Significantly raised PDA values were also found in patients with primary aldosteronism (PA, 27.8 +/- 9.0, n = 6, p less than 0.05), while their plasma norepinephrine levels (PNE, 169 +/- 39 pg/ml) tended to be lower than those of normal controls (206 +/- 20), showing an apparent dissociation between the values of PDA and PNE. Upright posture for 15 minutes induced a significant rise in PDA (p less than 0.05) in all subjects except PA patients. The postural changes of PDA, however, were invariably smaller than those of PNE (p less than 0.05). The resting values of PDA in normal, BH and EH patients showed a significant negative correlation with their mean arterial pressures (r = -0.301, n = 61, p less than 0.05) and a positive correlation with those of PNE (r = 0.381, p less than 0.01). There was no correlation between PDA and age in any group studied. These findings indicate that PDA might not be only a precursor fraction of neurotransmitters released from the sympathetic nervous system but could also represent a physiological function of the dopaminergic regulatory system. The varied but distinctive features of PDA status in various types of hypertension suggest the possibility that the peripheral dopaminergic mechanisms play an inherent role in the pathogenesis of hypertension.
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PMID:[Plasma dopamine concentrations in various types of hypertension]. 375 30

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 prevalence of hypertension among Kazak, Han, and Uygur nationalities living in Xinjiang Autonomous Region was 15.3%, 4.2%, and 2.1%, respectively; 257 men (92, 92, 83 subjects, respectively), aged 40-59 years were studied. The variables analyzed were serum total cholesterol, total protein, albumin, alpha-GT, triglyceride, plasma fibrinogen, and glucose concentrations; and urinary Na, K, Ca, Mg, urea nitrogen, taurine, sulfate, and NaCNS (an index of smoking), content. The data on nutritional variables indicated that Kazak subjects have a higher intake of sheep meat and milk, add salt to milk and tea, and take little starchy food, fresh fruits, and vegetables, as compared with Han and, especially, Uygur subjects. Statistical analysis showed Na intake (Na/K) exerted a prehypertensive effect; Ca (Ca/Mg) was implicated in blood pressure regulation; an antihyperlipidemic factor may exist in the Kazak diet; animal protein is correlated with elevated blood pressure; alcohol consumption may contribute to hypertension; and a mosaic model of metabolic disturbances, including high blood pressure, high blood sugar, impaired fibrinolytic activity, and hyperlipidemia, appear to exist.
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PMID:Nutrition, metabolism, and hypertension. A comparative survey between dietary variables and blood pressure among three nationalities in China. 376 Sep 14

Identification of inactive prorenin in the kidney has been difficult due to rapid proteolytic conversion of the inactive zymogen to its active form in the tissue or during homogenization and purification. Immunochemical methods, Western blotting, direct radioimmunoassay, and immunoaffinity chromatography were used to isolate and identify rat kidney renin and prorenin and to determine their molecular weights without complete purification. Antisera to pure rat renin were raised in rabbits. A specific reaction between the antisera and rat renin was demonstrated by double immunodiffusion, inhibition of enzyme activity, and competitive radioimmunoassay. The anti-rat renin IgG did not cross-react with purified human renin or rat spleen or kidney cathepsin D. The IgG showed binding affinity to both inactive renin as well as active enzyme. A combination of affinity chromatographies consisting of pepstatin-Sepharose, IgG-Sepharose, and Affi-Gel Blue permitted rapid and complete separation of inactive renin from active renin in rat kidney extract. Neither inactive nor active renin preparations exhibited aspartyl protease activity on hemoglobin used as substrate. The apparent molecular weight of inactive renin was estimated as 50,000 by gel filtration. Electrophoresis of partially purified inactive renin in sodium dodecyl sulfate (SDS) polyacrylamide gel followed by transblotting of proteins to a nitrocellulose sheet and immunochemical staining with anti-renin IgG showed a single protein band with a molecular weight of 48,000. Activation of inactive renin by trypsin was accompanied by the reduction of the 48,000-dalton native protein to a 39,000-dalton protein as determined by the SDS polyacrylamide gel electrophoresis and the transblotting.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension
PMID:Application of immunochemical methods to the identification and characterization of rat kidney inactive renin. 388 4

A syndrome, including microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and renal insufficiency, has been recognized to occur as a complication of antineoplastic therapy with mitomycin. The clinical presentation can vary from a chronic course with mild anemia and slowly progressive renal dysfunction to a fulminant course with severe anemia, rapid deterioration of renal function, and death. The optimal treatment of the mitomycin-associated MAHA syndrome is unknown. Therapy with steroids, antiplatelet agents, and heparin sodium has failed to reverse the MAHA. Plasmapheresis has improved the MAHA in a few patients without reversing the renal failure. We treated two patients who had MAHA and renal dysfunction during chemotherapy that included mitomycin; the MAHA and hypertension both objectively improved after treatment that included vincristine sulfate.
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PMID:Treatment of mitomycin-associated microangiopathic hemolytic anemia with vincristine. 395 31

Three patients with primary aldosteronism were treated surgically between February and September 1984. All patients had suffered from hypertension with U waves in ECG and laboratory examinations revealed hypokalemia, hyperaldosteronemia and suppressed plasma renin activity. The localization of the adrenal tumor was diagnosed accurately in all 3 patients by adrenal vein sampling and in 2 of the patients by PRP, CT scan, adrenal scanning with 131I-iodo cholesterol and adrenal venography. Adrenal tumors were surgically removed by unilateral adrenalectomy through the flank approach in all cases. Histological examinations of removed specimens showed adrenocortical adenoma. Removal of the adenoma caused a prompt reversal of the laboratory serum abnormalities and hypertension was normalized within 2 weeks postoperatively in all cases. Severe ventricular tachycardia (Torsades de Pointes) was observed suddenly in one of the patients after about 5 hours postoperatively. Therapy including conventional antiarrhythmic drugs, such as lidocaine or procainamide, and potassium administration failed to prevent the arrhythmia. Ventricular tachycardia was successfully treated and disappeared with the use of magnesium sulfate (MgSO4) intravenously. The serum potassium concentration was normal during the episode and the serum magnesium concentration, which was not detected before or just after the operation, was under the limit of normal range (1.4 mEq/l) after the use of magnesium sulfate. Hypomagnesemia which is retrospectively thought to be the result of primary aldosteronism may be responsible for the episode of postoperative ventricular tachycardia.
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PMID:[Three cases of primary aldosteronism including one case with postoperative ventricular tachycardia]. 396 10

A study to measure the pressor substance, called active pressor principle (APP), which is generated in incubated human plasma was performed using anesthetized and ganglion blocked rats. It was found that APP has properties characteristic of protein. APP was not extractable with mixtures of chloroform: methanol. APP was present at 50 to 70% saturation with ammonium sulfate. By treating the plasma with Pronase, the pressor activity of the plasma was almost completely abolished. The molecular weight of APP as determined by gel filtration was about 68,000. By adding diisopropyl fluorophosphate before incubation of the plasma, the generation of vasopressor substance was prevented. Treatment of the rat with captopril was ineffective in inhibiting the pressor effect of incubated plasma. It was found that the plasma of normal pregnant women generated significantly higher amounts of APP than the plasma of nonpregnant women. The plasma obtained from patients with pregnancy-induced hypertension generated significantly lower amounts of APP than the plasma of normal pregnant women. These findings suggest that a vasoactive protein (APP) is generated during simple incubation of plasma, and a serine protease is involved in the formation of this substance. Concerning the relevance of these results to blood pressure regulation in pregnancy-induced hypertension, probably APP is involved in blood pressure regulation via a compensatory mechanism.
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PMID:[Some properties of a vasopressor substance generated in human plasma by incubation and its clinical significance in pregnancy-induced hypertension]. 397 49


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