ISSN:0250-8095    

DOI:10.1159/000167534

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Several lines of evidence have implicated the kidney as having a pivotal role in the pathogenesis of essential hypertension. Whatever the initiating factors in an individual patient, it is becoming clear that a renal response must be involved to sustain the elevated blood pressure. There are a number of suggested mechanisms by which the kidney may influence arterial blood pressure. The importance of fluid volume and the role of sodium renal perfusion in elevated blood pressure has been well established. Recent investigations have suggested that sodium and calcium transport defects may exist in patients with essential hypertension. The accumulation of sodium can lead to calcium accumulation; calcium may therefore play an important role in the development of hypertension. Since the key role played by calcium ions in many biologic processes has been recognized, the role of calcium on peripheral vessels as well as the microvasculature of the kidney has become an area of stimulating and exciting research efforts.

ISSN:0250-8095    

DOI:10.1159/000167535

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Theoretical considerations suggest that the renal response to calcium antagonists may vary depending on the factors influencing basal vascular tone. Studies were conducted using the isolated perfused rat kidney to determine the response to calcium antagonists under conditions in which the determinants of renal vascular tone were accurately defined. With this model, calcium antagonists elicit vasodilation only in the presence of a vasoconstrictor. In this setting, however, the degree of vasodilation elicited depends on the nature of the vasoconstrictor employed. Thus, the reduction in renal perfusate flow (RPF) elicited by KCl-induced depolarization was completely reversed by the calcium antagonist, nitrendipine. In contrast, identical levels of vasoconstriction elicited by norepinephrine or angiotensin II were only partially reversed, suggesting that these agonists activate the renal vasculature by mechanisms that are more complex than membrane depolarization. Examination of the response of glomerular filtration rate (GFR) revealed that in the presence of norepinephrine and angiotensin II, nitrendipine exerted a preferential augmentation of GFR. Thus, concentrations that produced only modest effects on RPF increased GFR to levels equal to or exceeding control values. This selective augmentation of GFR did not occur during the renal vasoconstriction elicited by KCl. It is proposed that renal microvessels exhibit regional heterogeneity in regard to activation mechanisms and sensitivity to calcium antagonists. Calcium antagonists may selectively attenuate agonist-induced vasoconstriction of preglomerular vessels.

ISSN:0250-8095    

DOI:10.1159/000167536

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

In an attempt to predict outcome in acute renal failure (ARF) we have utilized multiple logistic regression to analyze clinical data from 151 patients with ARF seen over a 15-month period. Recovery of renal function occurred in 60% of patients with a 58% survival. Our analysis demonstrated sepsis, respiratory failure, and oliguria to be the major predictors of nonrecovery of renal function. A logistic equation was generated for prediction of outcome and was validated in a second independent group of patients with ARF. Prediction of outcome could be achieved with a sensitivity of 75% and a specificity of 80%. Maximum sensitivity (100%) was associated with a 17% specificity, while maximum specificity (98%) yielded a sensitivity of 20%.

ISSN:0250-8095    

DOI:10.1159/000167421

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

It is widely believed that the most common morphological lesion in children with the idiopathic nephrotic syndrome who manifest a frequently relapsing steroid-responsive course is the minimal-change lesion. However, there are no prospective renal biopsy studies in such patients to substantiate this assertion. We performed a renal biopsy in all children with early frequently relapsing steroid-responsive nephrotic syndrome during the years 1980–1984. In 16 affected children, only 4 (25%) had minimal-change lesion, 7 had IgM nephropathy, 3 had diffuse mesangial hypercellularity, and 2 had focal segmental glomerulosclerosis. Fourteen of these patients have required immunosuppressive therapy with cyclophosphamide. Long-term follow-up revealed that 10 patients have remained protein free, 4 have persistent proteinuria despite cyclophosphamide therapy, 1 had progressed to end-stage renal disease, and 1 is lost to follow-up. On the basis of these findings, we recommend that all children with nephrotic syndrome and an early frequently relapsing steroid-responsive course undergo a prompt renal biopsy. Such patients constitute a high-risk group with a spectrum of renal histopathological lesions characterized by an unpredictable response to therapy and an unfavorable prognosi

ISSN:0250-8095    

DOI:10.1159/000167422

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

In the isolated perfused rat kidney, the superimposition of a number of calcium entry blockers (CEB) upon norepinephrine vasoconstriction prompts an increase in the glomerular filtration rate (GFR) to a level substantially greater than the original value. A similar acute GFR response to CEB is manifested in the intact anesthetized rat with the renal perfusion pressure remaining constant. This glomerular response to CEB is accentuated in isolated perfused kidneys from Dahl salt-sensitive (DS) rats as compared with kidneys from Dahl salt-resistant (DR) rats. The disparities between DS and DR kidney responses are further amplified in the DS rat kidney after a high NaCl intake and the development of hypertension by the DS rat. In addition, vasoconstrictor responses to BAY-K 8644, a calcium entry facilitator, are accentuated in DS rat kidneys, and even more so following a high NaCl intake or ‘chemical sympathectomy’ with 6-hydroxydopamine. These results suggest that subtle changes in vascular and glomerular calcium entry modulation may be the key determinants of altered renal hemodynamics in salt-dependent hypertens

ISSN:0250-8095    

DOI:10.1159/000167538

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

This report is an attempt to gain more complete knowledge of the causes of the tendency to thrombosis in the nephrotic syndrome. Our purpose was to detect some rheological abnormalities in a group of nephrotic patients having normal renal function. Plasma and blood viscosity, erythrocyte filtration flow (EFF) and some indices of the carbohydrate metabolic state (glycosylated hemoglobin Ale; HbAlc, fasting glycemia and oral glucose tolerance test) were investigated in 10 patients with newly diagnosed primary nephrotic syndrome and 10 healthy subjects. EFF was determined in order to avoid variables depending upon plasma, white cells and hematocrit. The mean level of HbAlc was higher in the nephrotic group, in which we found 4 patients with impaired glucose tolerance according to the criteria of the National Diabetes Data Group. EFF was lower in nephrotic patients than in controls and correlated inversely with HbAlc. These findings indicate that nephrotic patients have a reduced red cell deformability which seems to be related to the abnormal carbohydrate metabolism commonly observed in this syndrome.

ISSN:0250-8095    

DOI:10.1159/000167423

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

Idiopathic diffuse crescentic glomerulonephritis without immune deposits is a variant of rapidly progressive glomerulonephritis which can account for up to 40% of crescentic nephritis. The prognosis may depend on both the severity of histological injury at presentation and the efficacy of treatment. Recent advances in therapy have improved the outlook further, and prolonged stable remissions with mild renal failure can occur which contrast with the previously common evolution towards end-stage renal failure within a few weeks. However, relapses in otherwise stable remission may be seen, and we describe a series of 6 acute relapses interrupting such prolonged remissions. The relapses were defined by clinical and histological means. This modification of the natural history of some crescentic glomerulonephritis may reflect new therapeutic strategies, and the relapses may reflect a cyclical nature to the disease evolution which was previously hidden by hemodialysis. The possibility of successive flares suggests that kidney biopsies should be repeated when a rapid deterioration of renal function occurs, since treatment such as high-dose steroids and/or plasma exchange can be again effective if started early.

ISSN:0250-8095    

DOI:10.1159/000167424

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

The intrarenal tubuloglomerular feedback mechanism operates at the site of contact between the thick ascending limb and glomerulus where specialized macula densa cells detect changes in tubular fluid composition and transmit information to the smooth muscle cells of the afferent arteriole. Increases in tubular fluid osmolality result in the transmission of vasoconstrictor signals and decreases in the rate of filtrate formation. Recent studies have identified two sites at which cytosolic calcium may play important roles. First, studies indicate that tubuloglomerular mediated vasoconstriction involves calcium mediated excitation contraction coupling of smooth muscle cells of the afferent arteriole. This calcium mediated event is sensitive to calcium channel blockade. Second, recent studies suggest that the macula densa cells may detect changes in tubular fluid osmolality through a cytosolic calcium system. The use of intracellular calcium antagonists further suggests that intracellular calcium mobilization is the primary mechanism responsible for increases in macula densa cytosolic calcium with increases in tubular fluid osmolality. Calmodulin and cyclic AMP may serve as modulators of this cytosolic calcium system. These studies suggest that calcium plays important roles in the regulation of renal hemodynamics.

ISSN:0250-8095    

DOI:10.1159/000167539

出版商:S. Karger AG    

年代:1987

数据来源: Karger

摘要:

In the present study, we have evaluated the relationship between serum ferritin (SF) levels, ‘hemochromatosis allele(s)’, blood transfusions and iron parenteral administration in 69 hemodialysis patients. We demonstrated significantly higher SF levels in patients with hemochromatosis allele(s) (HA+) than in patients without hemochromatosis alleles (HA-). In addition, HA+ patients who had received blood transfusions up to 15 months prior to the study had SF levels even higher than those without blood transfusions. On the other hand, HA- patients had normal levels of SF, independent of blood transfusions. After intravenous administration of 1 g iron saccharate, SF levels were significantly higher only in HA+ transfused patients. In conclusion, our study demonstrated that HA+ patients are at a higher risk of iron overload and therefore the use of transfusional and/or parenteral iron should be strictly limi

ISSN:0250-8095    

DOI:10.1159/000167425

出版商:S. Karger AG    

年代:1987

数据来源: Karger