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

To elucidate the role of oxygen free radicals and lipid peroxidation in the pathogenesis of early hypertension and atherosclerosis, we studied the native distribution of three primary arterial antioxidant enzymes (AEs). Specific immunohistochemical localization of superoxide dismutase (Cu-Zn SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) was examined in the arterial wall of New Zealand White rabbits: six sham-operated normotensive/normolipidemics (NT/NL), seven coarctation-induced hypertensive/normolipidemics (HT/NL), eight normotensive diet-induced hyperlipidemics (NT/HL), and six hypertensive/hyperlipidemics (HT/HL). All three AEs were confined primarily to the endothelium in NT/NL rabbit aortas. However, in HT and HL rabbits a greater proportion of the arterial wall, including the endothelium, inner media, and middle media, displayed immunolocalization of three AEs. Multiple linear-regression analysis revealed that more than 70% of the total variability in the depth of immunolocalization of arterial AEs could be explained by changes in blood pressure and/or total cholesterol. Also, levels of plasma and arterial cholesterol oxides were significantly different (p less than 0.05) in HT and HL rabbits compared with controls, with twofold increases in NT/HLs, threefold increases in HT/NLs, and fourfold increases in HT/HLs. We conclude that intense free-radical activity in the arterial wall of HT and HL animals is one possibility and that this occurs despite the presence of abundant AEs.
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PMID:Immunolocalization of native antioxidant scavenger enzymes in early hypertensive and atherosclerotic arteries. Role of oxygen free radicals. 155 32

The effect of Apocynum venetum leaf extract on hypertension, hyperlipemia, SOD content of erythrocyte, platelet aggregation rate, pulse wave transmission time (RP interval) and human diploid cell was studied to evaluate if it has some anti-aging effects. The mean BP in 60 cases of the treated group decreased from 171 +/- 19/98 +/- 11 mmHg to 154 +/- 22/91 +/- 10 mmHg and 148 +/- 17/89 +/- 10 mmHg after treatment for 4 and 8 weeks (P less than 0.01). The HDL-C in 40 cases of hyperlipemia increased from 47.5 +/- 13 mg% to 63.9 +/- 18 mg% (P less than 0.01). These results were better than those in the control groups. delta RPF was lengthened from 10.1 +/- 6.0 ms to 15.3 +/- 7.3 ms, which indicated that the cardiac performance was improved. No significant change of platelet aggregation rate was obtained after 5-8 weeks treatment. The retarding effect on cell aging was observed by the morphologic changes of nucleus and the increase of subcultivation from 77 to 80 generations. SOD content of erythrocyte was significantly increased from 546.1 +/- 51 micrograms/gHb to 574.6 +/- 42 micrograms/gHb in 20 cases. So Apocynum venetum leaf extract might have some anti-aging effects.
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PMID:[Observations on the anti-aging, antihypertensive and antihyperlipemic effect of Apocynum venetum leaf extract]. 277 75

The effects of topical application of agents which produce oxygen radicals on cerebral arterioles were studied in anesthetized cats. Xanthine oxidase plus xanthine, which produced superoxide anion radical, hydrogen peroxide, and hydrogen peroxide plus ferrous sulfate, which produced the free hydroxyl radical, induced sustained dilation, reduced responsiveness to the vasoconstrictor effect of hypocapnia, and destructive lesions of the endothelium and of the vascular smooth muscle. Similar effects were produced by arachidonate, 15-HPETE, and PGG2. The effect of arachidonate was inhibited by mannitol, a free hydroxyl radical scavenger, the effect of PGG2 was inhibited by SOD, the effect of 15-HPETE was inhibited by either catalase or SOD. These results suggest that these cerebral vascular abnormalities were produced by a single destructive free radical, probably the hydroxyl free radical, generated via interaction of superoxide and hydrogen peroxide. Cerebral vascular abnormalities similar to those produced by oxygen radicals were also seen after experimental concussive brain injury or after acute hypertension. After brain injury, activation of phospholipase C and increased brain prostaglandin concentration were demonstrated. The vascular effects of brain injury and acute hypertension were inhibited by free radical scavengers. The results suggest that, in these conditions, vascular damage is induced by oxygen radicals generated from arachidonate in association with increased prostaglandin synthesis.
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PMID:Oxygen radicals and vascular damage. 640 99

An enzyme immunoassay has been developed to measure human manganese-superoxide dismutase (Mn-SOD) in serum and urine. The assay can be done in less than 5 h, is highly sensitive (detecting limit, 0.1 ng of Mn-SOD) and simple. There is no interference from factors in serum or urine under assay conditions, and the method is specific for human Mn-SOD. Serum Mn-SOD concentrations were markedly increased in patients with liver diseases, but not in renal diseases. On the other hand, urinary Mn-SOD levels were elevated in a few patients with nephrotic syndrome and lung cancer, but were decreased in patients with hypertension. Furthermore, investigations were conducted on the clinical course of serum Mn-SOD levels in a case of alcoholic hepatitis, and on correlations between serum Mn-SOD and the conventional liver function tests. The localization of Mn-SOD in liver was also explored using immunofluorescent staining. The fluorescence was intense in the degenerated portions of liver tissue from a patient with drug-induced hepatitis.
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PMID:Enzyme immunoassay for manganese-superoxide dismutase in serum and urine. 676 11

Hypertension, cigarette smoking, and nicotine augment the clinical significance of other risk factors associated with cardiovascular diseases by mechanisms which are poorly understood. Since altered trace element metabolism and antioxidant status have also been implicated in these diseases, the present study investigated the interaction of nicotine treatment and hypertension on tissue trace element concentrations and select indices of antioxidant status. Spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats were treated with nicotine, via a time release tablet at an average rate of 75 micrograms/h for 6 weeks. Systolic blood pressure in nicotine-treated SHRs was significantly higher at weeks 3 and 6 of treatment than in the SHR-controls. Blood pressure in WKY rats was not affected by nicotine. Plasma and liver iron concentrations in the nicotine-treated SHR were higher than the SHR-controls and the WKY groups. Nicotine treatment did not affect plasma and liver zinc and copper concentrations or liver manganese (Mn) concentrations. Plasma ceruloplasmin activity was increased by nicotine treatment in the SHRs. Liver Mn superoxide dismutase (MnSOD) activities and glutathione concentrations, and liver and heart glutathione reductase activities, were higher in both groups of SHRs than in the WKY groups. Red cell SOD activity in the nicotine-treated SHR was lower than in the SHR-controls. In summary, blood pressure increased more rapidly in the nicotine-treated SHRs compared to the controls. The marked effects on antioxidant status observed were attributable more to hypertension than to the nicotine treatment.
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PMID:Comparative effects of 6-week nicotine treatment on blood pressure and components of the antioxidant system in male spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats. 774 May 54

Dietary effects of polyunsaturated fatty acids (PUFA) omega-3 on lipid peroxidation (LPO) and antioxidant system were studied in 73 patients with ischemic heart disease, hyperlipoproteinemia (HLPE) type IIa, IIb, IV and essential hypertension. Eiconol-enriched antiatherosclerotic diet has more potent hypolipidemic, hypotensive and thrombolytic action in association with inhibition of LPO, enhances SOD activity, keeps red cell catalase within normal. Vitamin E concentrations were not changed. It is suggested that eiconol addition to antiatherosclerotic diet causes no LPO induction and is pathognomonic for HLPE, hypertension and IHD patients.
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PMID:[Dietary effects of PUFA omega-3 on lipid peroxidation and antioxidant system in patients with IHD, hyperlipoproteinemia and hypertension]. 781 30

Previous results have shown that the contractile response to norepinephrine (NE) was enhanced in isolated aortae from SHR and normotensive Wistar parathyroidectomized rats. In this work we sought to characterize the contribution of endothelium-derived relaxing factor (EDRF) release to this effect which is not linked to hypertension. Parathyroidectomy (PTX) was performed by surgery on 5 week-old male Wistar rats. Five weeks later intact (E+) and rubbed (E-) aortic rings were mounted in an organ chamber for isometric tension recording. KCl-induced contractions were potentiated in PTX E+ aortae compared to sham operated (SO), (P < 0.05), but not in denuded E- aortae. Similarly NE (1 nM- 10 microM) induced a potentiated contractile response in PTX E+ (P < 0.01), but not in PTX E- rings; nevertheless the sensitivity did not change. After removal of endothelium, the expected enhanced contraction and sensitivity observed in SO rats was not present in PTX. The NO synthase inhibitor L-NAME (20 microM), enhanced sensitivity to NE in SO but not in PTX E+ aortic rings. In addition, hemoglobin (Hb, 10 microM) enhanced NE contraction in SO (P < 0.01) aortic rings, but to a lesser extent in PTX rat aortae. Moreover, in the presence of L-NAME or Hb, SO and PTX aortae displayed a similar contraction. Superoxide dismutase (SOD, 150 U/ml) diminished the NE contraction since NO was protected from degradation but the difference was still present between SO and PTX rat aortae, ruling out the possible implication of superoxide anions in the hyperreactivity of PTX aortae. On the other hand, A23187, which induces EDRF release, reduced the level of NE contraction as expected, but suppressed the PTX enhancing effect and in calcium-free solution the enhancement of contraction after PTX was not observed. These experiments extend to the rat the observations previously obtained in rabbit aorta: extracellular calcium is a major determining factor in NO production. Acetylcholine and A23187 (cumulative doses) produced an endothelium-dependent relaxation which was not significantly modified in NE-pre-contracted PTX aortae compared to SO aortae. L-arginine (100 microM), reversed the L-NAME inhibitory effect and induced an attenuated endothelium-dependent relaxation in PTX vessels (P < 0.01). In conclusion, in rat isolated aortae the enhancing effect of parathyroidectomy on norepinephrine and KCl contractions is due to a diminished endothelial nitric oxide production. This might arise via a decrease of the constitutive NO synthase activity in an extracellular calcium-dependent manner.
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PMID:Characterization of endothelium-derived relaxing factor involvement in the potentiating effect of parathyroidectomy on norepinephrine-induced rat aortic contraction. 818 95

Possible involvement of reactive oxygen species and nitric oxide in the pathogenesis of human essential hypertension was investigated. It was observed that both superoxide anion and hydrogen peroxide production by polymorphonuclear leukocytes and the plasma levels of lipid peroxides are higher in uncontrolled essential hypertension compared with normal controls. Nitric oxide levels measured as its stable metabolite nitrite, as an index of nitric oxide synthesis, revealed its levels to be low in hypertensive patients. Superoxide anion, hydrogen peroxide, lipid peroxides and nitric oxide levels reverted to normal values after the control of hypertension by drugs. The concentrations of anti-oxidants such as vitamin E and superoxide dismutase were found to be decreased in patients with uncontrolled hypertension. Several anti-hypertensive drugs inhibited lipid peroxidation in vitro. Angiotensin-II, a potent vasoconstrictor, stimulated free radical generation in normal leukocytes which could be blocked by calmodulin antagonists. These results suggest that an increase in free radical generation and a simultaneous decrease in the production of nitric oxide and anti-oxidants such as SOD and vitamin E occurs in essential hypertension. This increase in free radical generation can inactivate prostacyclin and nitric oxide and decrease their half life which can lead to an increase in peripheral vascular resistance and hypertension.
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PMID:Are free radicals involved in the pathobiology of human essential hypertension? 822 35

Highly active atrial natriuretic peptide III (haANP III) was administered for the treatment of heart failure due to pregnancy induced hypertension (PIH) in 7 patients with success. The heart failure was rapidly controlled within 24-48 hours with lowering of the blood pressure, disappearance of edema and urinary protein and alleviation of subjective symptoms. The plasma level of renin, angiotensin, aldosterone (RAA) and SOD all decreased. The results suggested that haANP III had the ability to facilitate the excretion of sodium and water, dilate the blood vessels and inhibit the action of RAA, and it could effectively reduce heart load and improve the cardiac function. Therefore, haANP III seemed to be an ideal new drug in treating heart failure in PIH, and it would have a wide scope for future development.
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PMID:[The use of synthetic haANP III in the treatment of heart failure in pregnancy induced hypertension]. 824 44

This paper was written on the following base: 31 women with severe pregnancy induced hypertension (PIH) were chosen randomly as an observation group, 32 healthy and gestational age matched pregnant women with uneventful delivery were served as control group. Blood samples were collected from intervillous space of placenta and umbilical cord vein after delivery. The levels of LPO, SOD and atrial natriuretic peptide (ANP) were measured separately. From the placenta point of view, the pathogenic mechanism of PIH and the relation to the occurrence of intrauterine growth retardation (IUGR) were discussed. The results showed: the concentrations of LPO, SOD and ANP of placenta and umbilical cord vein were higher in the PIH group than that in the control group. The difference between 2 groups was statistically significant. A positive correlation between LPO and ANP was found both in PIH group and in control group (r = 0.641, P < 0.02). The birth weight of newborn was 2,174 +/- 142 g in PIH group and 3,460 +/- 187 g in control group. The difference between them was significant (P < 0.01). It suggested that the pathogenesis of PIH and the occurrence of IUGR might be closely related to the high concentration of LPO in placenta and umbilical cord vein.
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PMID:[The relation between the levels of serum lipid peroxide, superoxide dismutase and atrial natriuretic peptide in placenta, umbilical cord vein and intrauterine growth retardation in pregnancy induced hypertension]. 824 46


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