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1.
Goldblatt hypertension was induced in rats by constricting the renal artery on one side. In one group of animals the contralateral kidney remained untouched (two-kidney hypertension), while in the other it was removed (one-kidney hypertension). In the two-kidney hypertension group, renin activity was higher than in the control animals, the fibrinogen was normal both in arterial and venous blood while in one-kidney hypertension the PRA was normal, but the fibrinogen was increased. A close significant correlation could be demonstrated between blood pressure and fibrinogen.  相似文献   

2.
Vascular duplex ultrasound duplex with simultaneous ECG registration was made to estimate the quantitative and time parameters of blood flow in the renal arteries with grade 1-2 arterial hypertension. There were increases in vascular resistance indices and acceleration phase index and a reduction in systolic phase index. There were correlations of the time parameters of blood flow in the renal arteries with age and lipidogram values.  相似文献   

3.
OBJECTIVE--To compare the mean nocturnal blood pressure of patients with various forms of renal and endocrine hypertension with that in patients with primary and white coat hypertension, and normal blood pressure. DESIGN--Ambulatory monitoring of blood pressure over 24 hours in a prospective study. SETTING--Two German centres for outpatients with hypertension and kidney diseases. SUBJECTS--176 normotensive subjects, 490 patients with primary hypertension including mild and severe forms, 42 with white coat hypertension, 208 patients with renal and renovascular hypertension, 43 with hypertension and endocrine disorders, and three with coarctation of the aorta. MAIN OUTCOME MEASURES--Fall in nocturnal blood pressure. RESULTS--Blood pressure in normotensive subjects fell by a mean of 14 mm Hg (11%) systolic and 13 mm Hg (17%) diastolic overnight (2200 to 0600). The falls in patients with primary and white coat hypertension were not significantly different. In all patients with renal and renovascular hypertension, however, the fall was significantly reduced (range of fall from 3/3 mm Hg to 7/9 mm Hg). In patients with hypertension and endocrine disorders the pattern of night time blood pressure was not uniform: patients with hyperthyroidism, primary hyperaldosteronism, and Cushing''s syndrome had significantly smaller reductions in blood pressure (6/8, 4/7, 3/6 mm Hg, respectively). In patients with phaeochromocytoma the mean night time blood pressure increased by 4/2 mm Hg. In patients with hypertension, primary hyperparathyroidism, and unoperated coarctation of the aorta the falls in blood pressure were normal. CONCLUSIONS--In normotensive subjects and those with primary hypertension there is usually a reduction in blood pressure at night. In all renal forms of secondary hypertension and in most endocrine forms the reduction in blood pressure is only a third to a half of normal. Patients with primary hyperparathyroidism and unoperated coarctation of the aorta show a normal reduction.  相似文献   

4.
The subjects who underwent diagnostic coronarography and detailed examination included 274 patients with lesions in the left coronary artery and its branches and 50 subjects without pathological changes in the coronary arteries or left ventricle. The authors also examined 149 patients with unchanged coronary arteries (67 with small vessel disease 42 with cardiomyopathy of various etiology; and 40 with other pathologies, such as the WPW syndrome, arterial hypertension, aortic stenosis, etc.). In addition to routine retrograde left heart catheterization and recording of the hemodynamic parameters demonstrated by ventriculography, the coronary blood flow was measured in all patients. Its normalized (specific) values are a basis for the coronary blood flow quantification in normal subjects, patients with the coronary heart disease (with insufficient oxygen supply to the myocardium), and those with cardiomyopathy of various genesis (when the myocardial oxygen demand increases together with the left ventricular myocardium mass).  相似文献   

5.
The ultrasonic location technique was used to measure the intima-media thickness (IMT) as well as the internal systolic diameter of and the linear blood velocity (LBV) in the cervical arteries in subjects with initial stages of hypertension. Correlation analysis elicited a temporal contingency between these parameters and daily average values of atmospheric pressure. Thus, the common carotid artery IMT tended to increase on high-pressure days. In addition, diameters of the common and internal carotid arteries and vertebral artery were narrowed and, consequently, LBV in these vessels increased. This relationship is more evident in men than women and in elderly subjects than young. These results are suggestive of a vasoconstrictive effect of high atmospheric pressure on these arteries. The relationship is not universal, as it is nonlinear for the diameter of the internal carotid artery and inverse for the external one. This implies different sensitivity of arteries to the factor under study and possible blood redistribution in the arterial tree depending on external pressure. The relationship was observed equally on the day of investigation and previous days, which points to its temporal stability.  相似文献   

6.
Urinary kallikrein excretion was studied in a number of animal models of hypertension. Kallikrein excretion was subnormal in spontaneously hypertensive rats as compared to Wistar/Kyoto rats and in rats made hypertensive by a clip on one renal artery. Kallikrein excretion was supranormal in rats made hypertensive by desoxycorticosterone and salt and in rats receiving desoxycorticosterone alone. It was subnormal after bilateral adrenalectomy. Kallikrein excretion increased in normotensive rats fed a low-sodium diet but was unchanged by a high-sodium diet. Thus, kallikrein excretion responded to changes in activity of sodium-retaining steroids and was not correlated with excretion of salt or water. In studies in dogs with stenosis of one renal artery kallikrein excretion was decreased on the stenoic side and the decrease correlated highly with the reduction in renal blood flow. While the role of the kallikrein-kinin system is still unclear the data indicate that the kidney may modify the initiation or maintenance of hypertension via this potent vasodilator system.  相似文献   

7.
《Médecine Nucléaire》2007,31(8):388-391
IntroductionDynamic renal scintigraphy with 99mTc-DTPA and captopril test is a non-invasive functional method for the diagnosis of renovascular hypertension. It allows differentiating between hypertension induced by renal arterial stenosis from primary arterial hypertension with an incidental stenosis.Case reportA 14-year-old girl, without previous medical history, developed a severe arterial hypertension with cephalgias and ears buzzing. Auscultation revealed a murmur in the left lumbar pit. Renal angiography objectified a stenosis of the infrarenal aorta due to a circumferential parietal thickening associated to renal arteries stenosis more marked in the left side. Dynamic renal scintigraphy after administration of captopril highlighted a marked collapse of the rate of tracer uptake exceeding 40% on the left side with an increase in the time of collecting on the right side testifying a frankly positive test prevailing on the left. A transluminal angioplasty of the left renal artery and a revascularisation surgery on the right side were carried out. The evolution was marked by an improvement of blood pressure figures.DiscussionDynamic renal scintigraphy using 99mTc-DTPA with captopril test constitutes a non-invasive process with a low dosimetry for the patients. Its principal goal is to affirm the role of renovascular stenosis in the origin of arterial hypertension and to determine which hypertensive patients with renal arterial stenosis can be treated successfully by surgical or endoscopic revascularisation of the kidney.  相似文献   

8.
Based on morphometric data, we calculate the structural parameters of the coronary vasculature as an optimal branching bed. We show (i) significant correlations between the diameters of the larger daughter and the parent vessel and between the diameter of the smaller daughter vessel and the asymmetry coefficient; (ii) differences in the structural parameters for two types of artery that deliver and distribute blood in the cardiac muscle; and (iii) the length-diameter relationships for different arteries. The coronary vasculature is characterized by asymmetrical branching and thus should be modeled with self-similar asymmetrical tree-like systems.  相似文献   

9.
We have recently concentrated our efforts on bioassay of plasma supernatant from animals with experimental low-renin hypertension (one-kidney, one-wrapped in dogs, and one-kidney, one-clip, and reduced renal mass in rats) for sodium-potassium pump inhibiting activity. We have observed changes compatible with inhibitory activity by using three different in vitro bioassays: 1) ouabain-sensitive 86Rb uptake by the normal rat tail artery, 2) short-circuit current in the toad bladder, and 3) membrane potential in the rat tail artery. We have also generated evidence suggesting that the humoral pump inhibitor(s) comes from or is influenced by the anteroventral third ventricle area of the brain and that it acts on the vascular smooth muscle cell at least in part by depolarizing the membrane. These findings are compatible with our 1976 hypothesis in which we proposed that in volume-expanded hypertension there is a circulating agent that suppresses cardiovascular membrane Na+,K+-ATPase, which results in reduced activity of the Na+-K+ pump and hence increased contractility of heart, arteries, and veins and that in blood vessels the increased contractility may be secondary to depolarization. We attempt to relate these findings to those in the literature on monovalent ion transport in blood cells of hypertensive subjects.  相似文献   

10.
Blood flow in the circle of Willis (CoW) is modelled using the 1-D equations of pressure and flow wave propagation in compliant vessels. The model starts at the left ventricle and includes the largest arteries that supply the CoW. Based on published physiological data, it is able to capture the main features of pulse wave propagation along the aorta, at the brachiocephalic bifurcation and throughout the cerebral arteries. The collateral ability of the complete CoW and its most frequent anatomical variations is studied in normal conditions and after occlusion of a carotid or vertebral artery (VA). Our results suggest that the system does not require collateral pathways through the communicating arteries to adequately perfuse the brain of normal subjects. The communicating arteries become important in cases of missing or occluded vessels, the anterior communicating artery (ACoA) being a more critical collateral pathway than the posterior communicating arteries (PCoAs) if an internal carotid artery (ICA) is occluded. Occlusions of the VAs proved to be far less critical than occlusions of the ICAs. The worst scenario in terms of reduction in the mean cerebral outflows is a CoW without the first segment of an anterior cerebral artery combined with an occlusion of the contralateral ICA. Furthermore, in patients without any severe occlusion of a carotid or VA, the direction of flow measured at the communicating arteries corresponds to the side of the CoW with an absent or occluded artery. Finally, we study the effect of partial occlusions of the communicating arteries on the cerebral flows, which again confirms that the ACoA is a more important collateral pathway than the PCoAs if an ICA is occluded.  相似文献   

11.
In renal artery stenosis severe enough to cause hypertension, angiotensin II maintains glomerular filtration rate (GFR) both in the initial high renin phase of hypertension and later when plasma levels are normal. Angiotensin II also maintains GFR in less severe stenosis, which does not cause hypertension. This homeostatic action of angiotensin II to maintain GFr has minimal effects on blood flow. In renal-wrap hypertension, plasma renin levels are elevated for longer than after renal artery stenosis, but in other respects this initial phase of the hypertension is similar to that after renal artery stenosis. GFR is reduced, the rate of development of hypertension is accelerated by angiotensin II, and angiotensin II maintains the glomerular filtration fraction. Renal resistance is markedly increased owing to both compression of the kidney by the hypertrophying renal capsule and to angiotensin II. Thus angiotensin II apparently plays a primarily homeostatic role in renovascular hypertension to maintain glomerular ultrafiltration. It is suggested that the angiotensin II may be formed intrarenally and may act on sites other than resistance blood vessels.  相似文献   

12.
Two cases of severe fibromuscular dysplasia of the renal arteries are described in which the diagnosis was made 12 and 11 years after renal angiography had shown the arteries to be normal. The discovery of hypertension preceded the diagnosis by two and 11 years respectively, and in one case hypertension was present at the time of the normal renal angiogram. The report suggests that fibromuscular dysplasia of the renal arteries is acquired and may not be present from birth. The importance of regular review in cases of severe hypertension is emphasised.  相似文献   

13.
The concentration of plasma adenosine 3'',5''-cyclic monophosphate (cyclic AMP) and plasma renin activity (PRA) were measured concomitantly in blood from both renal veins and in arterial blood in 22 hypertensive patients. In the nine patients with true renovascular hypertension the concentration of plasma cyclic AMP was greater in the venous effluent of the kidney affected by the renal artery stenosis than in that of the unaffected or less affected kidney. The arteriovenous difference in cyclic AMP concentration was less on the affected side in all but one patient. The arteriovenous differences in PRA identified the affected kidney as the source of hyper-reninemia and showed that renin release from the other kidney was suppressed. In the 13 patients with hypertension associated with but unrelated to renal artery stenosis there were no consistent patterns of cyclic AMP concentration or PRA in the venous effluent of the kidneys or of their arteriovenous differences. In renovascular hypertension the venous effluent of the kidney affected by renal artery stenosis contains not only more renin but also more cyclic AMP, owing to either increased cyclic AMP production or decreased excretion or extraction of cyclic AMP by the affected kidney. This unilateral increase in cyclic AMP concentration may become a complementary diagnostic feature of true renovascular hypertension.  相似文献   

14.
Vascular duplex ultrasound study with simultaneous ECG recording was performed to estimate the timing parameters of blood flow in the common carotid, internal carotid, and middle cerebral arteries in patients with grades 1 and 2 arterial hypertension. There was an increase in the blood flow acceleration phase index in the common carotid and middle cerebral arteries and a reduction in the systolic phase index in the internal carotid arteries. There were correlations of phasic blood flow parameters in the extra- and intracranial arteries with age and lipidogram readings.  相似文献   

15.
Studies in rat aorta have shown that the Na-K-2Cl cotransporter NKCC1 is activated by vasoconstrictors and inhibited by nitrovasodilators, contributes to smooth muscle tone in vitro, and is upregulated in hypertension. To determine the role of NKCC1 in systemic vascular resistance and hypertension, blood pressure was measured in rats before and after inhibition of NKCC1 with bumetanide. Intravenous infusion of bumetanide sufficient to yield a free plasma concentration above the IC(50) for NKCC1 produced an immediate drop in blood pressure of 5.2% (P < 0.001). The reduction was not prevented when the renal arteries were clamped, indicating that it was not due to a renal effect of bumetanide. Bumetanide did not alter blood pressure in NKCC1-null mice, demonstrating that it was acting specifically through NKCC1. In third-order mesenteric arteries, bumetanide-inhibitable efflux of (86)Rb was acutely stimulated 133% by phenylephrine, and bumetanide reduced the contractile response to phenylephrine, indicating that NKCC1 influences tone in resistance vessels. The hypotensive effect of bumetanide was proportionately greater in rats made hypertensive by a 7-day infusion of norepinephrine (12.7%, P < 0.001 vs. normotensive rats) but much less so when hypertension was produced by a fixed aortic coarctation (8.0%), again consistent with an effect of bumetanide on resistance vessels rather than other determinants of blood pressure. We conclude that NKCC1 influences blood pressure through effects on smooth muscle tone in resistance vessels and that this effect is augmented in hypertension.  相似文献   

16.
The vertebrobasilar system (VBS) is unique in human anatomy in that two arteries merge into a single vessel, and it is especially important because it supplies the posterior circulation of the brain. Atherosclerosis develops in this region, and atherosclerotic plaques in the vertebrobasilar confluence can progress with catastrophic consequences, including artery occlusion. Quantitative assessments of the flow characteristics in the VBS could elucidate the factors that influence flow patterns in this confluence, and deviations from normal patterns might then be used to predict locations to monitor for potential pathological changes, to detect early signs of disease, and to evaluate treatment options and efficacy. In this study, high-field MRI was used in conjunction with computational fluid dynamics (CFD) modeling to investigate the hemodynamics of subject-specific confluence models (n = 5) and to identify different geometrical classes of vertebrobasilar systems (n = 12) of healthy adult subjects. The curvature of the vessels and their mutual orientation significantly affected flow parameters in the VBS. The basilar artery geometry strongly influenced both skewing of the velocity profiles and the wall shear stress distributions in the VBS. All five subjects modeled possessed varying degrees of vertebral asymmetry, and helical flow was observed in four cases, suggesting that factors other than vertebral asymmetry influence mixing of the vertebral artery flow contributions. These preliminary studies verify that quantitative, MR imaging techniques in conjunction with subject-specific CFD models of healthy adult subjects may be used to characterize VBS hemodynamics and to predict flow features that have been related to the initiation and development of atherosclerosis in large arteries. This work represents an important first step towards applying this approach to study disease initiation and progression in the VBS.  相似文献   

17.
Summary The ultrastructure of the unconstricted superficial epigastric and femoral arteries is described in normal rats and in animals with hypertension induced by unilateral nephrectomy, by subcutaneous injections of desoxycorticosterone acetate and drinking of 1% NaCl. The femoral artery showed by far the greater response to the DOCA-saline treatment. In both vessels, the smooth-muscle cells changed from the normal spindle shape to a blunt ended outline with numerous pinocytotic vesicles and prolific collagen production. With long term hypertension, particularly in the femoral artery, the smooth-muscle cell profiles became very irregular. Hypertrophy of the organelles of the smooth-muscle cells was associated with an increase in the intercellular material which gradually changed from a mainly collagenous character to mainly vesicular. Lysosomal activity indicated cell disintegration. White blood cells adhere to the endothelium in hypertensive rats and there was an increase in subendothelial material. The number of intimal smooth-muscle cells increased noticeably in the femoral artery. In both arteries, the adventitial fibroblasts hypertrophied in hypertensive rats. In animals with an elevated blood pressure the morphological response was observed as early as 4 to 7 days after initiation of treatment.This work was supported by grants from the British Columbia Heart Foundation and the Medical Research Council of Canada.The authors are indebted to Miyoshi Nakashima for her invaluable assistance with these experiments.  相似文献   

18.
TGR(mREN2)27 (TGR) rats develop severe hypertension and an inverted circadian blood pressure profile with peak blood pressure in the daytime rest phase. The present study investigated the in vitro responsiveness of different arteries of TGR rats during day and night. Twelve-week-old TGR rats and normotensive Sprague-Dawley (SPRD) controls, synchronized to 12h light, 12h dark (LD 12:12) (light 07:00 19:00), were killed at 09:00 (during rest) and 21:00 (during activity), and endothelium-dependent relaxation by acetylcholine and vascular contraction by angiotensin II were studied by measuring isometric force in ring segments of abdominal aorta and mesenteric and renal arteries. In SPRD rats, consistent day-night variation was found, with greater responses to angiotensin II during the daytime rest span. In TGR rats, biological time-dependent differences were found in the renal vasculature, but not in the aorta and mesenteric artery. Relaxation of SPRD rat aorta and mesenteric artery by acetylcholine was greater at 09:00, whereas in TGR rats, day-night variation was absent (mesenteric artery) or inverted (aorta). In conclusion, based on the study of two time points, daynight variation in vascular contractility of aorta and mesenteric artery is blunted in TGR rats, whereas renal artery segments showed an unchanged daynight pattern compared to SPRD controls. (Chronobiology International, 18(4), 665 681, 2001)  相似文献   

19.
Acute experiments on cats have demonstrated the presence of renal artery sensitivity to the bloodstream velocity; the artery is enlarged with the blood flow increase and is narrowed with its decrease. The dilatation of the artery caused by the double increase of the blood flow (from 20 to 40 ml/min) is 23 +/- 8%. It has been established experimentally that carotid, femoral and renal arteries of cats respond to minor changes (of the order of 1 ml/min) in the volumetric velocity of the bloodstream by changing their diameters. Therefore, the arteries continuously follow the bloodstream velocity changes by changing their diameters. It may thus be concluded that the bloodstream itself is the artery dilatation factor.  相似文献   

20.
Renal function, the anatomic and functional status of the vena cava inferior, renal arteries and veins, and spermatic veins were evaluated in healthy individuals and patients with varicocele before and 12 months after laparoscopic ligation of the left spermatic vein. The renal vessels were assessed by color Doppler ultrasonography and renal function was examined by complex radionuclide study with 99mTc-pentatech. There were no significant changes in the diameter of renal arteries and vena cava inferior and the right arterial blood flow velocities in healthy individuals and patients. No difference were found in the diameter of renal veins and in the blood flow velocity in renal arteries and veins. The enlarged renal veins and decreased mean blood flow velocity in the left renal vein in healthy persons and patients with varicocele and lower blood flow in the left renal artery than in the right one indicate left-sided renal hypertension that is attributable to left renal vein overload due to a great variety of collaterals and to compression at the site of "a forcepts". At the same time 12-month postoperative ultrasonic, Doppler and complex radionuclide studies revealed no significant changes in the diameter and blood flow velocity in the left renal vein.  相似文献   

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