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

Information defining the renin-angiotension-aldosterone axis as a control system concurrently regulating salt balance and blood pressure has been applied to reexamine the role of renin in experimental and clinical forms of renovascular and renal hypertension, and thence to develop criteria for differentiating these entities. Experimentally, there are two models of renovascular hypertension; one is characterized by excess renin with reduced sodium (vasoconstrictor form) and the other by excess sodium with reduced renin (volume form). But with sodium depletion, the volume form converts to a vasoconstrictor form illustrating how the two factors coordinate to maintain blood pressure. In man, renovascular and renal hypertensions appear to be sustained by the same two mechanisms. Studies in man show that, in the absence of unilateral disease, the supine renal venous renin level in each kidney is consistently 24 percent higher than the peripheral level. Because of this constant relationship, the peripheral renin level is a measure of the renal secretion rate. Our studies indicate the curable unilateral renovascular hypertension is, in fact, renin-dependent vasoconstrictor hypertension. Three criteria, derived from four renin measurements, identify this situation: (1) Hypersecretion of renin is reflected by a high peripheral level when indexed against sodium excretion. (2) Lateralization of renin secretion with contralateral suppression rules out occult bilateral disease. It is indicated by V-A equal 0 from the uninvolved kidney. (3) (V-A)/A greater than 48 per cent from the ipsilateral kidney supports unilateralization. With data derived from patients with essential hypertension as a reference, the degree to which (V-A)/A is greater than 0.48 can be used to estimate the degree of renal ischemia, using Fick's principle. Corroborative evidence to support these three criteria can be developed from the blood pressure response to angiotensin blocking drugs or to antirenin therapy with propranolol. Clinical analysis validates these criteria to identify curable hypertension from unilateral renovascular or parenchymal disease. In patients with either occult or overt bilateral renal disease, the volume factor often predominates and is expressed by some suppression of plasma renin levels. Continued
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PMID:The renin axis and vasoconstriction volume analysis for understanding and treating renovascular and renal hypertension. 23 77

Three hundred fifteen patients with essential hypertension were classified according to low (18 percent), normal (59 percent) or high (23 percent) renin-sodium index. The proportion of patients with low renin hypertension progressively increased with increasing age and blood pressure, there being no difference between the sexes. Two high renin groups emerged: a younger group with early moderate hypertension, and an older group with severe hypertension consequent to possibly ischemic renal disease. Long-term beta blocking monotherapy in 137 patients resulted in a reduction of idastolic pressure to 95 mm Hg or less in 65 percent: 85 percent in those with high and 73 percent in those with normal renin activity; pressure was reduced to this level in only 1 of 24 patients (4 percent) with a low renin index. Antihypertensive efficacy was also related to age, since diastolic pressure was normalized in 80 percent of patients under age 40 years, in 50 percent of those aged 40 to 60 years, but in only 20 percent of those over age 60 years. Age may heolp in patient selection but is no substitute for the more reliable renin index, especially in patients over age 40 years, or with high pressure. Using studiew with propranolol as a standard, similar renin responses were obtained with two cardioselective beta1 type blocking drugs, atenolol and metoprolol, as well as with two nonselective beta2+1 receptor antagonists, LL21945 exhibiting prolonged receptor affinity and oxprenolol in slow release form. These long-acting drugs, which proved effective in single daily doses, could be of value in improving patient compliance...
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PMID:Antihypertensive beta blocking action as related to renin and age: a pharmacologic tool to identify pathogenetic mechanisms in essential hypertension. 24 9

In a consecutive series of 88 cases of carcinoma of the kidney and upper urinary tract seen at one hospital, 31 had malignant urothelial tumours of the renal pelvis or ureter. Forty-two per cent of these transitional-cell carcinomas occurred in patients with renal papillary necrosis following upon prolonged and heavy analgesic ingestion. Other possible aetiological factors were heavy cigarette smoking (61% of cases), long standing urinary obstruction or infection (23%) and possible occupational exposure (6%); in only four cases (13%) was there no identifiable aetiological factor. Those cases with analgesic nephropathy were characterised by renal functional impairment, hypertension and interstitial nephritis, but there was no difference in the clinical behaviour or pathological appearances of the tumours in the two groups. The clinical and experimental evidence that certain metabolites of phenacetin are carcinogenic is reviewed.
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PMID:Analgesic abuse, renal parenchymal disease and carcinoma of the kidney or ureter. 27 65

1. Direct intra-arterial blood pressure (radial artery) has been compared with indirect blood pressures using a regular sized adult cuff and a thigh cuff, with a mercury sphygmomanometer, in 24 hypertensive patients aged 62--84 years, and in 16 hypertensive patients aged 29--59 years. 2. The patients were studied because they were suspected of having a false elevation of their indirect blood pressure, since they had diastolic pressures over 100 mmHg, without hypertensive retinopathy, cardiac hypertrophy, or nephropathy. 3. Indirect diastolic pressure was falsely elevated by 30 mmHg or more in 12 out of 24 of the subjects over age 60, and in four of the 16 of those under age 60. Pseudohypertension (indirect diastolic greater than 100 mmHg, direct diastolic greater than 90 mmHg) was present in 12 subjects over age 60 and 5 under age 60. 4. Errors in indirect measurement of blood pressure are a serious problem, particularly in the elderly. Direct intra-arterial measurement may be useful in the management of hypertension.
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PMID:Pseudohypertension in the elderly. 28 97

Two major categories of membranoproliferative glomerulonephritis (MPGN) designated type 1 and 2 MPGN are currently recognized, largely on the basis of characteristic morphologic and immunofluorescence features. In contrast to experience reported from outside the United States, type 2 MPGN has been observed rather infrequently in this country. In a retrospective clinicopathologic study, 24 kidney specimens obtained from 10 children and young adults including seven females and three males (mean age: 13 years) with type 2 MPGN were identified using light, immunofluorescence, and electron microscopy. The histopathologic findings were related to the clinical course of each patient. When initially seen all patients had hematuria and proteinuria, three were nephrotic, and five were mildly hypertensive. A single patient was mildly azotemic. Eight patients had experienced an upper respiratory ifnection preceding their illness, although only one patient had evidence of a streptococcal pharyngitis. During a period of follow-up averaging 10 years, eight patients were nephrotic at some time during their illness and seven were persistently so. Hypertension was a major problem in eight patients and renal function declined markedly within a year of its onset in five. Persistence of the nephrotic syndrome from early onset of the disease, especially when associated with hypertension, was an additional sign of poor prognosis. Four patients developed chronic renal failure and three received one or more renal allografts. Histologic evidence of recurrent disease was found in allografts from the three patients as early as 7 months after transplantation in the absence of clinical features indicative of recurrent glomerulonephritis. It is concluded that type 2 MPGN is a chronic progressive renal disease of unknown etiology and pathogenesis which chiefly afflicts children and young adults. Hypertension and the early and persistent presence of the nephrotic syndrome suggest a poor prognosis. The disease appears to be largely unresponsive to conventional forms of therapy. The disease recurs with great frequency in allografts, often in the absence of clinical evidence of recurrent glomerulonephritis.
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PMID:Membranoproliferative glomerulonephritis with dense intramembranous alterations. A clinicopathologic study. 32 95

The survival of 305 patients with chronic renal failure treated at the Vancouver General Hospital by centre and home peritoneal dialysis, centre and home hemodialysis and cadaver renal transplantation over a 12-year period was analysed. There was decreasing survival with age except in patients undergoing home dialysis. Hypertension and analgesic nephropathy as primary causes of renal disease were associated with a poor prognosis. Hence age and diagnosis appear to be two of the main determinants of survival. Cardiovascular disease was the commonest cause of death but seven deaths were due to dialysis dementia. The results compare favourably with other published statistics.
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PMID:Results of 12 years' treatment of chronic renal failure by dialysis and transplantation. 34 97

We reviewed retrospectively 75 renal transplant arteriograms done during a 7-year period. Acute rejection and vasomotor nephropathy were not differentiated. Generalized cortical ischemia was diagnosed correctly in 23 of 30 cases but there were 7 falsely negative results. Renal artery stenosis was found in 7 of 17 cases in which the main indication for arteriography was hypertension. We conclude that the major role of transplant arteriography is in the diagnosis of larger vessel disease.
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PMID:Angiography in the diagnosis of renal allograft dysfunction. 34 73

The relationship of renal transplantation to new onset or persistence of previously established hypertension was analyzed in 164 transplant recipients in whom the renal allograft functioned for six months or longer. Of the 164, thirty-seven (23%) had normal blood pressure and 127 (77%) were hypertensive prior to transplantation. Following transplantation 83 patients (51%) were normotensive; high blood pressure was found in 81 (49%). Posttransplant hypertension could not be correlated with the recipient's original renal disease, age, sex, renal donor source, donor age, or maintenance dose of prednisone. More normotensive paients had undergone prior binephrectomy when compared with the hypertensive group (P less than .05). Mean serum creatinine levels was higher (2.0 mg/dl) in hypertensives than in normotensives (1.54 mg/dl) (P greater than .05). Selective renal veins' renin measurements in patients with severe hypertension were not helpful in predicting the beneficial effects of either bilateral nephrectomy or surgical correction of transplant renal artery stenosis.
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PMID:Relationship of renal transplantation to hypertension in end-stage renal failure. 35 41

Twenty-one insulin-dependent diabetics with azotemic nephropathy were evaluated for renal transplantation by selective coronary angiography and cine left ventriculography. All had hypertension, retinopathy, neuropathy, and required salt restriction plus diuretics for volume overload. There was no clinical or electrocardiographic evidence of ischemic coronary artery disease in twenty. Ten patients (five males, five females, mean age 29.3 years; mean duration of diabetes 21.9 years; mean serum cholesterol 239 mg%) had significant coronary artery disease, seven demonstrating focal abnormalities in left ventricular wall motion. Two patients (one male, one female; mean age 36.5 years; mean duration of diabetes 28.5 years; mean serum cholesterol 250 mg%) had no significant coronary artery disease, but demonstrated diffusely abnormal left ventricular wall motion with diminished ejection fraction. Thirty-eight percent had significant coronary artery disease unpredictable by electrocardiographic or clinical data. The finding of no significant coronary artery disease in 52% of a group with severe renal-hypertensive complications of diabetes is surprising. Two patients may have a demonstrated cardiomyopathy.
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PMID:Asymptomatic coronary artery disease: angiographic assessment of diabetics evaluated for renal transplantation. 36 Dec 77

Analgesic abuse is a major public health hazard in Australia, and analgesic nephropathy with consequent terminal renal failure is the underlying cause in 20% of the patients requiring dialysis and transplantation. Analgesics are invariably taken in the form of compounds and mixtures. In the aspirin-phenacetin-caffeine (APC) mixture, aspirin appears to be the major nephrotoxic agent and phenacetin appears to play a secondary and synergistic role. The renal disease associated with abuse of analgesics is characteristic and is part of a much wider clinical syndrome, the analgesic syndrome, which includes peptic ulcer disease (35%), anemia (60 to 90%), hypertension (15 to 70%), ischemic heart disease (35%), psychological and psychiatric manifestations, pigmentation, and possible gonadal- and pregnancy-related effects. The primary lesion in analgesic nephropathy is renal papillary necrosis (RPN), and this is a nephrotoxic effect common to all nonsteroid antiinflammatory agents. The most important factor in the management of patients with analgesic nephropathy is the cessation of analgesic abuse, and this leads to improvement and stabilization of renal function. A small proportion of patients will, however, deteriorate in relation to accelerated hypertension, persistent proteinuria, ischemic heart disease, and complications leading to nephrectomy. Patients with analgesic nephropathy are poor risk patients and have a poor prognosis, even after dialysis and transplantation.
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PMID:Analgesic nephropathy: etiology, clinical syndrome, and clinicopathologic correlations in Australia. 36 34


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