摘要:

SUMMARY The relative roles of tbe sympathetic nerrous system and renin-angiotefisin system in the development of two-kidney renal hypertension were studied using four groups of rats: Group I = vehicle control; Group II = 6-OH-dopamine (2 weeks prior to renal clipping then weekly throughout the study); Group III = adrenal medullectomy plus vehicle; Group IV = o-OHndopamlne plus adrenal medullectomy. Six weeks after clipping of a single renal artery, plasma renln activity (PRA) was comparably elevated in all groups. However, mean blood pressure (MBP) of Group II was lower than that of Group I controls (154.7 ± 6.8 vs 1973 ± 6.6 mm Hg respectively). Tbe MBP of Group III (207.0 ± 5.2 mm Hg) was not different from that of Group I whereas in Group IV (134.2 ± 18.0 mm Hg) it was markedly lower. All groups of rats were given a single dose of captopril (30 mg/kg p.o.) to inhibit the renin-angiotensin system. Despite differences in starting MBP, captopril caused similar reductions (38-50%) of MBP and increases in PRA in all groups. Similar results were obtained in two-kidney renal hypertensive rats with hypertension of 12 weeks' duration. It is concluded that the sympathetic nervous system does not contribute to the elevated PRA in two-kidney renal hypertensive rats but does contribute significantly to the development of hypertension In this model.

ISSN:0194-911X    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARY The acute effect of the orally-active converting enzyme inhibitor, captopril, was compared to that of saralasin in 13 patients with rations forms of hypertension on ad libitum sodium intake. A significant difference between the effects of the two drugs on mean arterial pressure (MAP) was found (&#151; 11 ± 3 mm Hg with saralasin, −2 4 ± 4.5 mm Hg after captopril). This difference was not correlated with control plasma renin activity (PRA). To determine the influence of the endogenous kallikrein-kinin system in the antibypertensive action of captopril, the effect of aprotinln (Apro), an inhibitor of kinin generation, on the MAP level achieved by captopril was assessed in five normal subjects and 15 patients with hypertension on ad libitum sodium intake. In normal subjects, captopril did not alter MAP, nor did Apro have any effect. In six patients with essential hypertension and normal PRA, MAP decreased by 5.5 ± 2 mm Hg following captopril, and Apro did not modify this level. In nine patients with renorascular hypertension (RVH), MAP fell by 22 ± 3 mm Hg after captopril administration, and Apro infusion induced a rise in MAP of 13 ± 1.7 mm Hg. A positive correlation between log control PRA and the effect of aprotinin was obtained (r= 0.63, p< 0.005). Apro had no effect in two patients with RVH who experienced a large drop in MAP during salasin. These results suggest that endogenous kinins as well as other substances, the generation of which is inhibited by aprotinin, may participate to the antihypertensire effect of captopril in patients with angiotensin-dependent hypertension. The lack of an aprotinin effect on the MAP level achieved during saralasin infusion suggests that the influence of the kallikrein-kinin system is related to the effect of captopril rather than the fall in arterial pressure resulting from angiotensin blockade.

ISSN:0194-911X    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARY Indices of structural change were examined in blood vessel walls subjected to increased tangential load in a new, in vitro model system. Ring segments of rabbit ear artery were maintained in organ culture medium for times up to 9 days. Tangential load was chronically applied with small, intraluminal springs made of 0.010 in. diameter stainless steel wire. The applied load was considered to produce lerels of circumferential wall tension corresponding to those induced by a range of levels of blood pressure. The indices of stnicturai change examined were the uptake of radioactively-labelled proline and thymidine, which indicate protein synthesis and cell division respectively. Increased uptake of both proline and thymidine was noted in artery segments under elevated mechanical tension after a latency of 3 to 4 days. The degree of uptake was related to the degree of calculated wall tension elevation. The work indicated that cell division and protein synthesis can be induced in the blood vessel wall by increased wall tension alone, in vitro.

ISSN:0194-911X    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARY In 307 Natire American (NA), 1784 black (B), and 7777 white (W) children in grades 1,2, and 3 in Minneapolis schools (99% overall response rate), blood pressure (BP) was measured supine in the right arm after 5 minutes' rest by trained technicians using a random zero BP device. In addition, height, weight, pulse rate, and triceps skinfold thickness were measured. Among children aged 6 through 9 years, NA children had slightly higher systolic BP (SBP) than B or W children overall (mean SBP: NA 106, B 104, W 105 mm Hg) and for nearly all age sex groups. In contrast, Phase 4 and 5 diastollc BP (DBP) were consistently lower in NA children (mean DBP4: NA 64, B 69, W 67 mm Hg); NA children also had lower pulse rates, greater pulse pressures, similar or slightly lower mean BP, similar height, greater weight, body mass index, and triceps skinfold. Multiple regression analyses revealed that the slightly higher SBP in NA children was explained almost entirely by greater ponderosity. However, the lower DBP could not be explained statistically by any of the variables measured.

ISSN:0194-911X    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARY Normal plasma contains inactive renin, which becomes active when plasma is dialyzed to pH3.3 and to pH 7.5, or treated with pepsin or trypsin. Under optimal conditions, each of these procedures activated the same quantity of renin, which was not further increased by repeating or combining two procedures, thus suggesting that the same pool of inactive renin was activated by each procedure. When plasma was fractionated by gel filtration, dialysis activated very little renin in eluates. Trypsin activated renin, but under some conditions also destroyed renin. Pepsin fully activated the inactive renin in eluates without evidence of destruction of renin. The pepsin-activated renin of normal plasma eluted from Sephadex G-100 in a peak of apparent molecular weight (MW) 58,000 and from Sephacryl S-200 with apparent MW 53,000, like big renin in plasma of patients with diabetic nephropathy. Inactive renin was usually increased in amount in plasma of sodiumdepleted normal men, but the elution volume did not change with sodium intake. When renin was fully activated in plasma incubated with pepsin or trypsin, the apparent MW of the main peak of big renin did not change appreciably. Inactive renin in plasma was usually increased after sodium depletion, but the elution volume did not change. Active renin of normal plasma had an apparent MW near 41,000 on both gels. Thus, we conclude that big renin is present in normal plasma in amounts at least equal to and usually greater than active renin (the ratio depending on sodium intake) and that pepsin activation readily demonstrates big renin in eluates from gel filtration.

ISSN:0194-911X    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARY Measurement of patient compliance is essential if management of low compliance is to be performed efficiently. We assessed the ralue of several easily obtained clinical assessments compared to quantitative pill counts among 134 newly treated hypertensive male steelworkers during the first 6 months of their treatment with antihypertensJve medication. Patient's self-reports obtained on structured interview correlated best with pill count compliance (r= 0.74, p< 0.0001). Patients overestimated their compliance by an average of 17% but 90% of those who admitted to being noocompliant were found so. Qualitative urinary chlorthalidone and hydrochlorothiazide levels and changes in serum potassium, uric acid, and blood pressure also correlated with pill count compliance but were less accurate than interviews. Assessment of the patient's"health beliefs" and a variety of sociodemographic and health traits and perceptions did not provide useful information on compliance. Interviewing the patient is a simple and useful approach in assessing compliance with antihypertensive therapy.

ISSN:0194-911X    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARY Malignant hypertension was induced in rats by aortic ligation above the left renal artery. After 7- and 28-day periods of hypertension, the characteristics of the vascular disease were studied and the kidney below the aortic ligation was removed. The blood pressure and the vascular disease were reexamined at the end of the first and fourth weeks after nephrectomy. The evolution of the vascular disease was assessed in the contralateral kidney, in the heart, and in the superior mesentery. The results obtained allowed the following conclusions: 1) when the predominant lesions are of fibrinoid necrosis and moderate intimal hyperplasia without fibromucoid changes (initial phase), the hypertension and the hypertensive vascular disease are completely reversible after the nephrectomy; 2) when the predominant lesions are proliferative endarteritis with fibromucoid changes (chronic phase), neither the hypertension nor the vascular disease are reversible after the left nephrectomy and during the period of follow-up. Therefore, the type of vascular lesion seems to be one important determinant of the reversibility of the hypertensive process after nephrectomy.

ISSN:0194-911X    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARY 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 normotensire subjects (NT). Observations were made in hydropenia (C) and during sustained isotonlc saline volume expansion (E; 3% increase in body weight). The intrarenal renous pressure (IRVP) was used as an index of peritubular capillary hydrostatic pressure, and the efferent arteriolar colloid osmotic pressure (COP,n) 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< 0.001); glomerular filtration rate (GFR) 122 ± 4 ml/min/1.73 m* (128 ± 3, p> 0.05); renal blood flow (RBF) 1172 ± 38 ml/min/1.73 m1(1298 ± 48, p< 0.05); IRVP 25.0 ± 1.0 mm Hg (24.8 ± 0.8, p> 0.05); COP.tt33.0 ± 0.7 mm Hg (31.9 ± 0.6, p> 0.05); and UN.V 140 ± 13 $mole/min (161 ± 12, p> 0.05). During E, the increase of UH.V in HT was more than double that of NT (p< 0.001) while IRVP did not change in either group (p> 0.05) and COP.frfell by 26% (p< 0.001) in both groups. GFR and RBF increased by 18% (p< 0.001) and 19% (p< 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.

ISSN:0194-911X    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARY Experimental aortic coarctation in rats is accompanied by non-pressure-related increases in hindlimb total vascular resistance and its neurogenic and structural components. To investigate the role of the sympattaoadrenergic system, we partially constricted or sham-constricted toe abdominal aorta in rats age 6 weeks that had had adrenal demedullation and guanethidine injections to produce peripheral sympatfaectomy (SYMP rats, N&#149;= 13-coarcted, 14-sham-coarcted) and in sham-sympatbectomized, sham-demedullated control rats (SHAM rats, n = 14-coarcted, 11-sham-coarcted). In both SHAM and SYMP rats with coarctation, tail and femoral arterial pressures did not increase but carotid pressures rose by 18-25% (p< 0.01), accompanied by significant increases in heart weight/body weight. However, arterial pressures in SYMP were 30% lower than those in SHAM rats (p< 0.005). In the pump-perfused (blood, lml/min), innervated, isolated hindlimbs of SYMP, compared to SHAM rats, the effect of acute section of local nerves on resistance was reduced and denervation hypersensitivity was documented. In contrast to SHAM, coarctation in SYMP rats was not accompanied by increases in total hindlimb resistance and its neurogenic component; there were, however, significant rises in the humoral-myogenic (p< 0.01) and structural (p< 0.05) components. Thus, the sympatho-adrenergic system influences arterial blood pressure and accounts for the elevated neurogenic component of peripheral vascular resistance in coarctation hypertension In rats, but does not account for the elevated structural component of resistance. An unknown humoral factor, or factors, may be incriminated in the latter.

ISSN:0194-911X    

出版商:OVID    

年代:1980

数据来源: OVID

摘要:

SUMMARY The relationships between urinary kallikrein (Uk.,), and plasma renin activity (PRA), urinary aldosterone (U«ldo), Na+balance, SK+, and renal function were studied in essential hypertensives (EHT) and normals. Utalwas measured by a radiochemical esterolytic assay. We studied 18 white patients with EHT (15 men, 3 women) ages 31.6 ± 2.1 (SEM) yrs, BP 138 ± 2/95 ± 2 mm Hg. and 12 white normals (NLS) (7 men, 5 women) ages 30.2 ± 2 3 yrs, BP 112 ± 4/71 ± 2 mm Hg. All received a 5-day diet of 400 raEq Na+, 80 mEq K+/day, and 5 days of 10 mEq Na+, 80 mEq K+/day. All achieved Na+balance by Day 5. On Day 5 of the low Na+diet, 24 hr. U$, in EHT was 15.8 ± 2.4 (esterase units/24 hr) rs NLS, 17.0 ± 2.8. PRA was the same in EHT and NLS, but U.ldowas higher in NLS. (Day 5, low Na+, EHT, U«ld0− 29.4 ± 33 Mg/24h. vs NLS 41.8 ± 4.7, p< 0.02). Analysis of individuals showed that all NLS increased U after salt restriction, while 3 EHT decreased U$j after salt restriction. This abnormal response In EHT was not related to abnormalities in Undo, PRA, Na+balance, SK+, or creatinine clearance. In 3 EHT with low-renln EHT, toe UkaJresponse was normal. In two of four patients with primary aldosteronism, Ut., was normal despite increasedU.ido- The Urn response to salt restriction is abnormal in some EHT, unrelated to U$ao or PRA, suggesting either a primary defect in U$, and/or the presence of other factors modulating U$, in EHT.

ISSN:0194-911X    

出版商:OVID    

年代:1980

数据来源: OVID