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

Reactions of the blood flow and of the diameter of mesentery arterioles were studied in vivo after the application of histamine (100--500 gamma) and adrenaline (1--10 gamma) in normal rats and in the animals with renal hypertension. A decrease of sensitivity of the microvessels, 10--30 mu in diameter, to the action of these substances was shown in the animals with hypertension.
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PMID:[Responses of the mesenteric microcirculatory bed of rats with experimental renal hypertension to histamine and adrenaline]. 111 35

The Page kidney is a remediable form of renal hypertension. It is usually seen in young male patients with an antecedent history of blunt renal trauma, followed by a subcapsular or perirenal hematoma causing compression of the renal parenchyma and hypertension. Radiographic studies demonstrate the presence of an extrinsic mass compressing the kidney. Divided function studies and renal vein renin determinations confirm the functional significance of this process in the etiology of hypertension. Treatment may initially consist of observation. However, if hypertension persists then decortication and evacuation of the encysted fluid are indicated. In long-standing cases, although nephrectomy may be necessary, the chance of relieving hypertension is excellent.
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PMID:The Page kidney: a correctable form of arterial hypertension. 111 14

The sympathetic tone of the splanchnic nerve was quantified in renal and deoxycorticosterone (DOC) hypertensive rats under pentobarbital anesthesia by measuring equivalent stimulation frequency (ESF). ESF is the frequency of stimulus to the peripheral cut end of the nerve required to restore the preseverance level of arterial pressure. It is assumed to represent the average discharge rate of the nerve before severance. ESF was markedly increased in DOC hypertension 2 weeks after initiation of the DOC-salt treatment. It was relatively decreased after 10 weeks, but was still higher than in the controls. In renal hypertension (clipping of the left renal artery), ESF was decreased considerably 2 weeks and slightly 10 weeks after clipping. When the contralateral kidney had been removed simultaneously with clipping (clip plus uninephrectomy, ESF was not significantly changed. It is suggested that the sympathetic nervous system participates greatly in the pathogenesis of DOC hypertension but not of renal hypertension.
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PMID:Sympathetic nervous activity in renal and DOC hypertensive rats. 112 Nov 43

The changes in systolic blood pressure, plasma renin activity (PRA), and sodium balance were studied during the first 3 weeks of the development of renal hypertension in rats with an undisturbed contralateral kidney. Moderate hypertension (160 to 180 mm Hg) was reached after application of a 0.25-mm solid clip; severe hypertension (200 to 230 mm Hg) developed after application of a 0.20-mm solid clip. Basal levels of PRA in peripheral blood increased only in rats with a 0.20-mm clip, when blood pressure had already risen to 160 to 180 mm Hg. Elevated peripheral PRA, however, may have contributed to the initial increase of blood pressure in both groups of hypertensive rats, as indicated by higher late-afternoon PRA values at the peak of the normal diurnal rhythm of PRA. PRA in renal venous blood from the clipped kidney increased during the development of both moderate and severe hypertension at a rate quantitatively related to the rise in blood pressure. During the first 8 to 10 days after application of both sizes of clips, sodium retention per gram gain in body weight was significantly higher than in the sham-operated controls. Subsequently, sodium balance and blood pressure stabilized in animals with a 0.25-mm clip. In the rats with a 0.20-mm clip, sodium balance returned to control levels and became even lower than in the sham-operated group. Despite this negative sodium balance, blood pressure showed a further rise. These results suggest that in rats with an undisturbed contralateral kidney, a positive sodium balance has a role in the early phase of the development of renal hypertension. The enhanced plasma renin activity also probably contributes to the early phase, but appears to make a major contribution to the further development of severe hypertension.
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PMID:Plasma renin and sodium balance during development of moderate and severe renal hypertension in rats. 113 77

To test the hypothesis that renin is circulating in pressor amounts in renal hypertension, two-kidney Goldblatt hypertension was produced in rats. After hypertension had been present for a variable period of time (4 to 21 days), the ischemic kidney was removed, and an infusion of rat renin was started immediately to replace the endogenous renin that the ischemic kidney had been releasing. Since the amount of renin released by the clipped kidney was not known, the amount infused was regulated by a feedback mechanism set to keep the mean blood pressure at the same level as before ipsilateral nephrectomy. Hypertension remission was therefore prevented by this procedure. The PRA at the end of the renin infusion was similar to that prior to the ipsilateral nephrectomy. This finding indicates that the levels of the PRA circulating in renal hypertension are within the pressor range, thus supporting the hypothesis that renin plays a role in the pathogenesis of the acute or semiacute phase of renal hypertension. However, the participation of other factors cannot be ruled out since no correlation was found between PRA and blood pressure.
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PMID:Role of renin in the pathogenesis of renal hypertension. 113 78

1. The acute malignant phase of hypertension in rats with an untouched contralateral kidney is characterized by salt and fluid loss, increased fluid intake, decrease in body-weight gain, and reduced food consumption. Plasma concentrations of sodium and potassium were reduced, and plasma angiotensin II rose to about four times normal. 2. To investigate the significance of an untouched contralateral kidney for the development of the acute malignant phase in renal hypertensive rats, comparative studies were undertaken in unilaterally nephrectomized rats with stenosis of the remaining renal artery and in rats with bilateral renal artery stenosis. In addition, the effect of declamping one renal artery in rats with bilateral stenosis was studied. 3. In unilaterally nephrectomized rats, no signs of sodium and fluid loss were demonstrable, despite marked increase in blood pressure. Similarly, rats with bilateral renal artery stenosis had no acute malignant phase of hypertension. 4. In hypertensive rats with bilateral stenosis, removal of the clip from one renal artery was followed by an immediate fall in blood pressure and a subsequent gradual increase. Eleven of sixteen rats lost salt and fluid and developed an acute malignant phase. Plasma angiotensin II was high and serum urea elevated. 5. Consumption of 2% saline in addition to water as drinking fluid had a beneficial effect, since only five of fourteen rats showed signs of the acute malignant phase, which were milder than in rats on water only. 6. It is concluded that the untouched contralateral kidney is responsible for the negative salt and water balance and its consequences, which are characteristic of the acute malignant phase of experimental renal hypertension.
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PMID:Salt loss as a possible mechanism eliciting an acute malignant phase in renal hypertensive rats. 114 33

The authors report a case of hypertension due to dysplasia of the renal arteries in a young man, and found the same disease in siblings. Two sisters and one brother also had renal hypertension, whereas the other relatives were unaffected. Two similar cases found in the world literature, did not permit the authors to determine the cause of this disease. This case is reported in order to stimulate research and the discovery of new cases.
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PMID:[Familial reno-vascular hypertension (author's transl)]. 115 15

Reduction of the (expanded) body fluid volumes found in some patients with renal hypertension may be essential in the management of these cases. Illustrative examples are given of this "volume dependent" form of hypertension. In such patients, plasma renin activity (PRA) is low. Other forms of hypertension may be regarded as caused by "inappropriate renin secretion". Most often, however, both factors are operative. This concept is supported by experimental evidence obtained in animals. The combined effect of salt depletion (which increases PRA) and beta-adrenergic blockade with propranolol (during which treatment PRA is lowered) was systematically studied in 3 groups of hypertensive patients (including one group with chronic renal insufficiency). The results indicate that this combined therapy lowers the blood pressure in various types of hypertension, the effect being sometimes more than additive. There was, however, no correlation between the PRA levels and the blood pressure decrease after salt depletion or after propranolol. Consequently, on the basis of the PRA values, no group of patients could be identified for which this treatment would be specifically indicated.
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PMID:Observations of the role of body fluid volumes and plasma renin activity in the management of hypertension. 115 38

The difference of the prognosis between essential and renal hypertension (chronic glomerulonephritis) was examined by compairing the survival rate of the patients, and the effect of lability of blood pressure and the effect of the response to hypotensive drugs on the prognosis of the two types of hypertension was observed. The prognosis of renal hypertensives was remarkedly worse when it was compaired with the prognosis of essential hypertensives. More then 80% of the latter was still alive after ten years, while the mortality rate of the former after 5 years was only 20%. Each factor of severity (diastolic pressure, optic fundi, cardiac, cerebrovascular and renal complication) in non severe patients (group O-II) did not differently affect the survival rate of both hypertensives. Diverse prognosis was observed in severe patients (group III-IV), depending on each factor of severity. In renal hypertension the survival rate was extremely low when the patients had high diastolic pressure, severe cardiac and cerebrovascular complication. It was not so low in the patients with severe ophthalmoscopic change. The prognosis of essential hypertension was poor in the order of severe cerebrovascular complication, renal complication and cardiac complication. The survival rate of the patients with high diastolic pressure or severe ophthalmoscopic change was considerably high. The patients with both renal and essential hypertension showed greater survival rate when the blood pressure was much more reduced by bed rest or antihypertensive drugs during the first hospitalization.
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PMID:Comparison of the prognosis of hypertension associated with chronic glomerulonephritis with that of essential hypertension. 115 38

1. The relationships between the renin-angiotensin-aldosterone system, sodium and potassium balance and systolic blood pressure were studied during development of moderate (160-180 mmHg; clip i.d. 0.25 mm) and severe (200-230 mmHg; clip i.d. 0.20 mm) renal hypertension in rats with an undisturbed contralateral kidney. 2. In severely hypertensive rats renin activity in the peripheral plasma increased from day 9, by which time the systolic blood pressure was elevated to 160-180 mmHg. The rate of total corticosteroid and aldosterone production in vitro increased from day 14 and plasma renin substrate concentration increased from day 24. In moderately hypertensive rats, none of these changes occurred. 3. During the first 10 days after the application of 0.25 and 0.20 mm clips, sodium and potassium retention/g gain in body weight were higher than in sham-operated controls. During the next 10 days, the positive balance stabilized in animals with a 0.25 mm clip whereas, in animals with a 0.20 mm clip, sodium and potassium balance returned to the level of the sham-operated controls through increased renal losses. Despite these changes the systolic pressure rose further in animals with a 0.20 mm clip. 4. The initial sodium retention could be a factor in the early rise of blood pressure and could account for the delay in the rise of peripheral plasma renin activity. The subsequent loss of the retained sodium and potassium during the development of severe hypertension could have facilitated the rise in peripheral plasma renin activity, but did not initiate this rise.
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PMID:Changes in the renin-angiotensin-aldosterone system and in sodium and potassium balance during development of renal hypertension in rats. 116 91


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