摘要:

In 6 volunteers with normal renal function, we investigated the effects of various kinds of protein (soy, lactoprotein and beef) and various amounts of an intravenously administered amino acid solution on glomerular filtration (GFR) and effective renal plasma flow (ERPF). As for the protein-induced changes in renal function, rises in GFR and ERPF were lowest with soy protein, and highest with beef (baseline GFR, 110 ± 5; soy, 122 ± 5; beef, 131 ± 5 ml/min/1.73 m2; mean ± SEM). High doses of intravenous amino acids induced arise in GFR comparable to that after beef (132 ± 5 ml/min/1.73 m2). In a combined test a liquid mixed meal together with intravenously administered amino acids induced a comparable increase of the GFR (baseline 114 ± 5 versus 129 ± 5 ml/min/1.73 m2). When investigating 9 patients with chronic renal insufficiency after 4 weeks of low protein intake (LP) and after 4 weeks of high protein intake (HP), GFR and ERPF rose significantly under baseline conditions (GFR-LP 41 ± 9 versus GFR-HP 45 ± 9 ml/min/1.73 m2, p < 0.02; ERPF-LP 169 ± 39 versus ERPF-HP 180 ± 40 ml/min/1.73 m2, p < 0.02; paired Wilcoxon). At the end of both dietary periods a comparable rise in renal function could be induced through acute stimulation (GFR-LP 20 ± 5, GFR-HP 16 ± 4; ERPF-LP 23 ± 7, ERPF-HP 22 ± 3%). Glucagon levels tended to fall during a HP diet (glucagon-LP 69 ± 11 versus glucagon HP 50 ± 12 ng/l), whereas an acute rise in glucagon levels could be induced by acute stimulation at the end of both dietary periods (glucagon-LP 163 ± 18, glucagon-HP 173 ± 58%). We conclude that renal function remains variable even in patients with moderate to severe renal insufficiency and that acute stimulation remains possible to the same extent after LP and HP intake. Our results also suggest different underlying mechanisms for the acute and chronic stimulation

ISSN:1660-8151    

DOI:10.1159/000185742

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

We have investigated β2-microglobulin (β2M) synthesis and release by blood leukocytes and isolated mononuclear phagocytes. Recent interest in β2M has developed since the discovery that this protein forms amyloid fibrils in patients undergoing long-term, chronic hemodialysis and that these patients have greatly elevated levels of monomeric β2M in their circulation. Since hemodialysis-related factors that increase β2M production are unknown, we evaluated β2M production by freshly prepared leukocytes and monocyte-derived macrophages under a variety of conditions. We utilized a novel enzyme-linked immunoabsorbant assay to quantitate β2M concentrations, and monitored interleukin-1 and β2M synthesis by immunoprecipitation. Incubation of leukocytes with Cuprophan or Hemophan does not increase β2M release. Adherence of macrophages onto polystyrene or Cuprophan membranes induces neither interleukin-1 nor β2M synthesis or release. In contrast, interaction of macrophages with lipopolysaccharide, γ-interferon, tumor necrosis factor, or interleukin-1 induces synthesis and release of β2M, indicating that β2M synthesis is increased during macrophage activation. Exposing leukocytes or macrophages to changes in osmotic or oncotic pressure induces a rapid release of β2M and interleukin-1 into the cellular medium. These results suggest that during hemodialysis, β2M production is more likely to result from endotoxin contamination, or osmotic and oncotic changes, rather than direct interaction of mononuclear phagocytes with Cupro

ISSN:1660-8151    

DOI:10.1159/000185743

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The effect of intravenous 1α(OH)D3 on circulating intact parathyroid hormone (PTH) and COOH-terminal immunoreactive PTH was examined in 21 patients on chronic hemodialysis. The patients were treated for 3 months with increasing doses of 1α(OH)D3 under careful control of serum Ca2+. 1α(OH)D3 was given intravenously at doses of up to 4 μg three times a week, and blood samples were obtained every week, including 1 week before treatment (basal control). No patients were treated with oral vitamin D metabolites. At the end of the study intact PTH levels were reduced by an average of 67 ± 6%, and COOH-terminal immunoreactive PTH levels were reduced by 35 ± 6%. Serum Ca2+ was kept within normal levels, but showed a slight increase from 1.17 to 1.30 rnmol/l. An effect of calcium on PTH secretion could not be excluded, but an effect of 1α(OH)D3, independent of serum Ca2+ was also found. This effect may be mediated by 1,25(OH)2D3, assuming a large capacity of the 25-hydroxylase in the liver to convert 1α(OH)D3 to 1,25(OH)2D3. Also, the parathyroid glands may possess receptors for 1α(OH)D3 with an effect similar to that established for the 1,25(OH)2D3 receptors. Thus, although the exact mechanisms ofthe action of 1α(OH)D3 have not yet been completely clarified, it is concluded that intravenous administration of 1α(OH)D3 may be of benefit in the treatment of secondary hyperparathyroidism

ISSN:1660-8151    

DOI:10.1159/000185744

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Cardiac arrhythmias were evaluated in 100 patients undergoing regular maintenance hemodialysis for chronic renal failure by Holier ECG monitoring a 72-hour period beginning on the day of hemodialysis. Clinically significant ventricular arrhythmias (more than 700 beats/24 h) were found in 18 patients (the frequent group) in whom premature ventricular contractions (PVCs) were recorded frequently during and for 4 h after hemodialysis. In the frequent group, the values of the serum calcium concentration times those of phosphorus were significantly higher than those of patients without PVCs (the no arrhythmia group) or those with fewer PVCs (less than 700 beats/day; sporadic group) (54.9 ± 3.5 vs. 43.8 ± 3.2, 43.0 ± 1.8, respectively; p < 0.005). Also, in the frequent group, the percent fractional shortening of the left ventricle, as measured by two-dimensional echocardiography, was significantly lower than those in the no arrhythmia and sporadic groups (30.7 ± 1.8% vs. 40.7 ± 1.9%, 37.7 ± 1.1%, respectively; p < 0.01). On the other hand, in those with frequent premature atrial contractions, the left atrial end-diastolic dimension was significantly enlarged (42.1 ± 1.2 mm vs. 36.5 ± 1.1 mm, 38.1 ± 0.9 mm, respectively; p < 0.01). From these results, we conclude that impaired cardiac performance and a high calcium phosphate product predialysis may be correlated with an increased incidence of ventricular arrhythmias in uremic

ISSN:1660-8151    

DOI:10.1159/000185745

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The concentration changes, during hemodialysis treatment, of 18 characteristic uremia compounds, analyzed by high-pressure liquid chromatography in sera of renal patients were studied. Pre- to postdialysis concentration ratios (dialysis ratio, D) varied from 0.83 to 3.04 for the different solutes. A division into three solute groups, on the basis of their D values, could be rationalized qualitatively from data on protein binding and dialyzer clearance. One group showed low dialysis ratios which could be explained from plasma protein binding. The second group had intermediate D values, comparable to those of creatinine. For some of the members of the third group, high D values might indicate a compartmentalization and resistance to mass transfer across biological membranes. Among the latter are the tubularly secreted hippuric acid and p-hydroxyhippuric acid. For most of the (protein-bound) solutes, protein binding was shown to decrease during hemodialysis. Protein binding levels were higher after dialysis only for hippuric acid and the as yet unidentified fluorescent solute designated UFK8. In conclusion, the change of serum concentrations and of protein binding resulting from hemodialysis treatment are presented and are compared for 18 accumulating solutes in sera of patients with end-stage renal failure.

ISSN:1660-8151    

DOI:10.1159/000185746

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Sixteen stable renal transplant patients on chronic ciclosporin (CS, n = 8) or azathioprine (AZA, n = 8) treatment were given trimethoprim (TMP) 160 mg twice a day for 7 days. This TMP dose did not affect glomerular filtration, as 99mTc-DTPA clearance was unchanged in both groups. TMP did, however, increase serum creatinine and reduce creatinine clearance in all patients. This effect was most pronounced in CS-treated patients. We conclude that even at the moderate dosage, as employed presently, TMP blocks tubular secretion of creatinine. This route for creatinine excretion is quite important as the clearance ratio between creatinine and DTPA averaged 1.21 in CS-treated patients and 1.05 in AZA-treated patients before TMP treatment. During TMP the ratio was reduced to 0.95 and 0.99, respectively, suggesting a complete cessation of tubular creatinine secretion by TMP. TMP did not, however, significantly affect other markers of renal tubular function.

ISSN:1660-8151    

DOI:10.1159/000185747

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Pepsinogen A (PGA) and Pepsinogen C (PGC) are circulating low-molecular-weight proteins. Both have been shown to be almost freely filtered through the glomerular basement membrane. In man, only PGA is present in significant amounts in the urine. This prompted us to investigate the tubular reabsorption of PGA and PGC in man. Fifty-eight 24-hour urine specimens and a serum samples were obtained from 21 healthy subjects. Eight serum and urine samples were obtained after raising the serum PGA and PGC levels by oral administration of omeprazole. Filtered loads of PGA and PGC and tubular reabsorptions were calculated. PGA was already present in the urine at filtered loads below the tubular reabsorption maximum (10.6 ± 3.5 mg/24 h; mean ± SD) that was reached at serum PGA levels above 66 μg/l. Furthermore, intraindividual variation in tubular reabsorption of PGA was observed. Urinary excretion of PGC remained very low and the tubular reabsorption maximum for PGC was not reached. These data show that the presence of large amounts of PGA in the urine of healthy volunteers is due to a low affinity of the tubules for PGA. Tubular affinity of PGA changes in time and factors responsible for these changes require further investigation. The absence of PGC from the urine is due to a high affinity of the tubules for PGC and a high capacity compared to normal filtered loads. The similarity between PGA and PGC molecules suggests that minor differences in molecular structure can be responsible for large differences in tubular reabsorpti

ISSN:1660-8151    

DOI:10.1159/000185748

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Serotonin metabolism was investigated in 15 patients (8 women, 7 men) with decreased renal function (clearance of endogenous creatinine = 0.07–0.74 ml/s) and compared to the values obtained in healthy controls. In spite of thrombocytopenia, the patients’ platelet serotonin concentrations (1.99–47.6 nmol/109 platelets) as well as the plasma serotonin levels (190–2,176 nmol/l) were significantly higher than in controls (1.36–7.87 nmol/109 platelets, p < 0.05; 0–500 nmol/l, p < 0.001). The low urinary serotonin output (0–414 to 167–1,187 nmol/24 h in controls, p < 0.001) probably reflects its decreased synthesis in the residual renal parenchyma. 5-Hydroxyindolacetic acid was excreted in normal amounts. The impairment in serotonin metabolism is closely correlated with the decrease in renal function. The data document accumulation of serotonin in the circulation. This impairment could contribute to platelet hyperaggregation and/or consumptive hypocoagulation, maintenance of hypertension, and acceleration of

ISSN:1660-8151    

DOI:10.1159/000185749

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

A rat model of moderate uraemia is described in which uraemic animals attain normal food intake and weight gain. Despite the low levels of the induced uraemia, which has been well defined, changes in plasma amino acid concentrations associated with experimental uraemia still occur. It appears from this study that a reduction in food intake is not a major factor in the aetiology of the plasma amino acid changes seen in uraemia and that the model may prove useful in future studies of experimental chronic renal failure.

ISSN:1660-8151    

DOI:10.1159/000185750

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

We evaluated the effect of indomethacin on renal function in a sodium-restricted state in control subjects and in patients with systemic lupus erythematosus (SLE) without major disease activity and with normal or only slightly impaired glomerular filtration rate (GFR). In the patients with SLE indomethacin 150 mg daily induced a fall in GFR of mean 15.8%, while effective renal plasma flow remained constant. Neither effective renal plasma flow, nor GFR changed significantly in the controls. One should be aware that nonsteroidal anti-inflammatory drugs (NSAID) may decrease GFR in SLE, also in patients without disease activity and with normal or only slightly impaired GFR. As effective renal plasma flow remained constant, it is suggested that the indomethacin-induced fall in GFR in SLE is caused by mesangial contraction.

ISSN:1660-8151    

DOI:10.1159/000185751

出版商:S. Karger AG    

年代:1989

数据来源: Karger