ISSN:1660-8151    

DOI:10.1159/000186591

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

To test the accuracy of urea kinetic modeling (UKM), the classic fixed-volume model UKMf, two variable-volume models (UKMvb and UKMvd), direct dialysis quantification (DDQ) and a partial dialysate collection method (PDC) were evaluated in 15 stable, high-hematocrit patients. Urea generation rate (G) was also determined from a 1-week collection of total dialysate and urine (OWC). The results, except distribution volumes, were highly correlated. However, Kt/V, the normalized whole-body urea clearance, was about 8% higher with UKMvb and UKMvd. Two of three simple equations for Kt/V rendered grossly deviating, but highly correlating, results. The normalized protein catabolic rate was 8% higher with UKMvd. With OWC as reference, UKMvb and UKMvd overestimated G by 19 and 15%, respectively. All results of PDC closely followed those of DDQ. This method may be an alternative for exact quantification. Before using a new UKM method it should be compared to an established reference method.

ISSN:1660-8151    

DOI:10.1159/000186592

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

The tubular transport of urate was studied in 40 hypertensive patients and in 20 normal subjects by means of pyrazinamide and benzbromarone tests. There was a marked decrease in urate excretion per nephron in hyperuricemic patients with essential hypertension. Serum uric acid correlated inversely with fractional excretion of urate (r = -0.7450, p < 0.001). Presecretory and postsecretory reabsorption of urate did not significantly differ between hypertensive patients with high uric acid levels and control subjects. Urate secretion was significantly reduced in hypertensive patients and in those with hyperuricemia showed a twofold decrease. Serum uric acid correlated inversely with tubular secretion of urate (r = -0.7091, p < 0.001) in hyperuricemic, hypertensive patients. These findings indicate that impaired tubular secretion of urate is a potential mechanism of hyperuricemia in essential hypertension.

ISSN:1660-8151    

DOI:10.1159/000186593

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

The possibility that the renal hemodynamic abnormalities associated with ciclosporin (CS) administration are enhanced in nephrotic patients (NP), leading to severe impairment of renal function and/or to modifications in proteinuria, has not hitherto been tested. Ten NP and 8 healthy subjects (NC) were examined before and after oral CS administration (10 mg/kg body weight in NP and 12 mg/kg body weight in NC: a lower dosage was adopted in NP because of edema overestimating the actual body weight) under water diuresis by standard renal clearance methods. Basal blood volume was lower in NP. Blood CS levels were not significantly different in the two groups. Basal glomerular filtration rate (GFR) was similar in NP and NC, while renal plasma flow (RPF) was lower in NP. After CS, both GFR and RPF significantly decreased in the two groups, but the percent decrease in inulin clearance was greater in NP. Filtration fraction increased only in NC. Basal renal vascular resistances were greater in NP, and significantly increased after CS in both groups. Basal fractional sodium excretion (FENa) was lower in NP: after CS FENa decreased only in NC. Neither plasma renin activity, nor plasma aldosterone changed after CS. When urinary protein excretion (Up) was corrected by GFR, no change was observed after CS; by contrast, selectivity of proteinuria (as assessed by the CigG/CTransferrin ratio) markedly increased. Our data indicate that CS induces a greater fall in the GFR in hypovolemic NP than in healthy subjects, probably because in the former GFR becomes extremely plasma flow dependent. No change in UP per unit of GFR is observed after CS, while a striking improvement in urinary protein selectivity occurs, probably as a result of a fall in glomerular ultrafiltration coefficient by CS.

ISSN:1660-8151    

DOI:10.1159/000186594

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

The determination of renal antigens in the urine with an immunoassay, based on monoclonal antibodies (moabs), is a noninvasive test system for the analysis and monitoring of renal injury. New moabs allowing an immunohistologic dissection of the human nephron were generated by a direct intrasplenic immunization of mice with pathologic urine samples. A sandwich enzyme immunoassay was developed to quantitate renal cell membrane antigens in the urine. While antigen excretion in healthy individuals is low, preliminary data of a clinical investigation suggest the usefulness of these assay systems in diagnosis of tubular injury in human kidney transplant recipients. The immunoassay can provide very early hints of renal graft rejection prior to the appearance of clinical symptoms or the detection by routine clinical laboratory investigations.

ISSN:1660-8151    

DOI:10.1159/000186595

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

Primary as well as secondary hyperparathyroidism may be associated with anemia, and parathyroidectomy (PTx) may improve or even heal it. The precise link between the two conditions is still matter of dicussion. The purpose of the present study was to investigate possible effects of PTx on serum immunoreactive erythropoietin (iEPO) in secondary (group I, n = 23), and primary (group II, n = 16) hyperparathyroidism patients, and in 3 patients undergoing cervicotomy for thyroid mass removal (group III). In group I patients, circulating iEPO levels rose from 23.1 ± 4.8 mU/ml before PTx to 28.2 ± 5.0 and 245 ± 125 mU/ml (mean ± SEM) at day 7 (p = NS) and 14 after PTx (p < 0.003), respectively. Reticulocyte count increased 2 weeks after PTx: from 61,000 ± 13,317 to 86,533 ± 13,462/mm3 (p < 0.05, n = 23). In 4 of these patients serum iEPO levels could be measured again 12–24 months after PTx. They were slightly higher than those determined before PTx: 37.0 ± 8.4 versus 31.8 ± 13.5 mU/ml. Their hematocrits were also higher than before PTx: 12.8 ± 0.9 versus 11.0 ± 0.9 g/dl. In group II patients, serum iEPO levels remained unchanged after PTx: 17.5 ± 2.0 mU/ml before PTx and 20.0 ± 3.0 mU/ml 14 days after PTx. The reticulocyte count, however, increased significantly 2 weeks after PTx: from 25,103 ± 3,000 to 40,827 ± 4,080/mm3 (p < 0.01). In group III patients, serum iEPO, reticulocyte count, and hemoglobin remained stable after surgery. Since all group I patients had received vitamin D supplementation after PTx, we studied an additional group of 14 chronic dialysis patients (group IV) who received either calcitriol (1 μg/day, n = 7) or placebo (n = 7) during 14 days. The patients on calcitriol treatment, but not those on placebo, had a significant decrease of serum iEPO: 18.6 ± 4.9 versus 16.0 ± 4.2 mU/ml (p < 0.03). In conclusion, PTx led to a striking increase of serum iEPO and blood reticulocytes in uremic patients with secondary hyperparathyroidism, and an increase of reticulocyte count, but not of iEPO, in patients with primary hyperparathyroidism. Marked changes of circulating PTH, extra- or intracellular calcium and phosphorus concentrations as well as of tissue sensitivity to EPO after PTx could all be responsible. In contrast, the surgical procedure and the therapeutic increase in plasma calcitriol do not app

ISSN:1660-8151    

DOI:10.1159/000186596

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

It has been reported that patients with azotemia have reduced red blood cell (RBC) deformability. Since this is a major determinant of whole-blood viscosity (WBV) and rigid RBCs increase WBV disproportionately relative to the level of hematocrit, it is conceivable that sustained improvement of hematocrit with recombinant human erythropoietin (rhEPO) therapy in azotemic patients might result in abnormally raised WBV. To address this concern, WBV and plasma viscosity (PV) were measured in 9 adult patients (4 men, 5 women) with anemia (mean hematocrit 29.2 ± 2.7%) and azotemia [mean serum creatinine concentration 339.85 ± 102.44 μmol/l (3.8 ± 1.1 mg/dl)] before and after 6 months of treatment with rhEPO (50–175 U/kg given intravenously thrice weekly). Baseline and post-treatment hematocrit, WBV and PV were compared to values derived in 50 normal adult subjects with normal renal function [25 women, 25 men; mean serum creatinine concentration 79.56 ± 8.84 μmol/l (0.9 ± 0.1 mg/dl), mean hematocrit 42.4 ± 3.7%]. To compare rheologic factors at subnormal hematocrits, blood from subjects with normal renal function was diluted with autologous plasma to achieve a range of hematocrits from 20 to 50%. Because hematocrit is higher in men than in women, we compared men and women study patients with a normal group of the same sex. After 6 months of treatment with rhEPO, (1) mean hematocrit rose 38% from 28.3 ± 2.8 to 39.0 ± 1.0% in men (p = 0.005) and 32% from 30.0 ± 2.9 to 39.6 ± 0.8% in women (p = 0.004); (2) WBV increased in proportion to the ratio noted in our healthy reference group with respect to hematocrit (r = 0.64); (3) WBV measured at high (230 s-1) and low (23.0 s-1) rates of shear in men and women was not significantly different from normals (p = 0.5) for all values of hematocrit studied; (4) PV [1.65 ± 0.15 millipascal · second (mPa s) for men, 1.64 ± 0.07 mPa s for women] did not change in either sex and was not significantly different from that of normals (1.63 ± 0.14 mPa s for men, 1.57 ± 0.08 mPa s for women). We conclude that treatment with rhEPO (1) restores hematocrit to normal in anemic nondialysis patients with renal insufficiency, (2) WBV increases appropriately in both sexes with respect to the rhEPO-induced rise in hematocrit and (3) PV is unaltere

ISSN:1660-8151    

DOI:10.1159/000186597

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

The pharmacokinetics and dose response of recombinant human erythropoietin (rhEPO), administered intravenously and subcutaneously, were studied in chronic haemodialysis (HD) patients and in patients on chronic ambulatory peritoneal dialysis (CAPD). Furthermore, two products differing in the presence of albumin as preservative were compared. Although the pharmacokinetics differed after intravenous and subcutaneous administration, the dose response was the same. There is no statistically significant difference in the pharmacokinetics between the rhEPO in HD and CAPD, nor had the presence of albumin as preservative an influence on the pharmacokinetics.

ISSN:1660-8151    

DOI:10.1159/000186598

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

Hypotheses concerning the development of uric acid and gouty nephropathy suggest that the initiating disease mechanism involves an interaction between uric acid or monosodium urate monohydrate (MSUM) crystals and renal tubular epithelial cells. We have studied the interaction of these crystals with Madin-Darby canine kidney (MDCK) cells, which exhibit many of the characteristics of cells of the collecting duct epithelium. Addition of MSUM crystals to monolayer cultures of MDCK cells leads to the formation of reaction sites, localised areas which are raised above the monolayer forming a 3-dimensional structure. These reaction sites are evident within 4–8 h and appear to be initiated by the interaction of a single crystal or small number of crystals with a single cell. With time, both cells and crystals accumulate at the site. By 24 h most reaction sites involve 6–12 cells and numerous crystals. Interaction of MSUM crystals and MDCK cells not only involves the attachment of crystals to cells but, by 8 h, some crystals appear to be completely or partially covered by the cell membrane, and MDCK cells appear to react by growing around the crystals. Transmission electron microscopy shows that crystals are found not only within cells, but also within the intercellular spaces. Within the cells, crystals have been shown in vacuoles containing lysosomal enzymes, indicating the formation of a phagolysosome. Ultimately, enzyme release occurs. These studies support the hypothesis that some interstitial deposits of urate and uric acid in the kidney may be derived from intratubular deposits that react with the tubular epithelium and pass into the interstitium; loss of tubular integrity may not be a prerequisite for crystal migrat

ISSN:1660-8151    

DOI:10.1159/000186599

出版商:S. Karger AG    

年代:1991

数据来源: Karger

摘要:

We investigated the effect of excess complement factor D on the immune complex solubilization activity (ICSA) of serum. First, we estimated the concentration of factor D, ICSA and the hemolytic activity via the classical complement pathway (CH50) in the sera of 16 healthy individuals and 36 patients on hemodialysis for end-stage renal failure. The serum concentration of factor D in these patients (mean ± SD: 12.12 ± 2.38 μg/ml) was significantly higher (p < 0.001) than that in the healthy subjects (1.02 ± 0.11 μg/ml). In this study, peroxidase and antiperoxidase rabbit IgG were used as immune precipitates for ICSA. The ICSA in patients (45.8 ± 7.4 normal human serum %, NHS%) was significantly lower (p < 0.001) than that in the healthy subjects (100.2 ± 12.5 NHS%). There was no difference in CH50 between the sera of the patients (31.8 ± 2.5) and that of the healthy group (32.4 ± 2.6). Second, we determined that increasing amounts of purified factor D added to fresh serum resulted in a decrease in ICSA. This occurred in the serum of a healthy individual as well as in that of a patient. CH50 did not change regardless of the concentration of factor D used. There was an increase in C3 conversion in the sera to which purified factor D had been added, as observed by crossed immunoelectrophoresis. It is suggested that ICSA had deteriorated due to the excess of factor D, which had activated the alternative pathway of co

ISSN:1660-8151    

DOI:10.1159/000186600

出版商:S. Karger AG    

年代:1991

数据来源: Karger