Longitudinal study of proteins in plasma and dialysate during continuous ambulatory peritoneal dialysis (CAPD)

The aim was to evaluate plasma proteins during continuous ambulatory peritoneal dialysis (CAPD) in relation to dialysis losses, membrane permeability, renal insufficiency, and time on CAPD. Ten male patients, established on CAPD for at least 14 months, were studied every 8 weeks for 56 weeks. Blood and dialysate from the morning exchange were analysed for urea, creatinine, and 7 proteins, and used to calculate dialysate to plasma concentration ratios (D/P). These ratios were not significantly changed suggesting that permeability remained constant. However, there was a trend for beta 2-microglobulin, creatinine, and urea to increase progressively. After 56 weeks, beta 2-microglobulin had increased from 27.9 to 31.3 mg/L (p less than 0.05) and creatinine 1006 to 1099 mumoL/L (p less than 0.05) and both correlated with time on CAPD (p less than 0.001). Plasma alpha 1-acid glycoprotein, albumin, transferrin, IgG, IgA, and complement C3 were not significantly changed, although IgA and complement C3 were each negatively correlated with time on CAPD (r = -0.70 and -0.67, respectively), creatinine (r = 0.51 and -0.54), and urea (r = -0.61 and -0.61) (p less than 0.001 for all). It is concluded that increases in beta 2-microglobulin, creatinine, and urea are not due to loss of membrane permeability but reflect a slight increase in uraemia. Long-term decreases in immunological proteins may be caused by uraemia or progressive depletion.     

Effects of antihypertensive drugs on renal function and atrial natriuretic polypeptide in spontaneously hypertensive rats with renal ablation

To determine whether pharmacological control of blood pressure could affect the renal function and levels of atrial natriuretic polypeptide (ANP) in spontaneously hypertensive rats (SHR) with renal ablation, and to ascertain the benefits of antihypertensive drugs, we studied effects of oral administration of captopril (50 mg/kg/day), an inhibitor of angiotensin converting enzyme, benidipine (3 mg/kg/day) and nilvadipine (10 mg/kg/day), newly developed blockers of calcium channel, and indapamide (10 mg/kg/day) for 14 days on systolic blood pressure, serum creatinine, blood urea nitrogen, and plasma ANP concentration in SHR subjected to surgical removal of the left kidney and infarction of two-thirds of the right kidney (5/6 nephrectomy) a week before. Three weeks after the surgery, systolic blood pressure (mmHg) in the untreated group was 253 +/- 9 (n = 10), in the captopril group 156 +/- 9 (n = 7, p less than 0.05), in the benidipine group 197 +/- 9 (n = 7, p less than 0.05), in the nilvadipine group 146 +/- 9 (n = 7, p less than 0.05) and in the indapamide group 206 +/- 5 (n = 7, p less than 0.05). Serum creatinine (mg/100 ml) was lower in the captopril group (0.58 +/- 0.02, n = 7, p less than 0.05) and in the benidipine group (0.50 +/- 0.03, n = 7, p less than 0.05) but not in the nilvadipine group and in the indapamide group 3 weeks after 5/6 nephrectomy compared to the untreated group. Blood urea nitrogen was also lower in the captopril group and in the benidipine group but not in the nilvadipine group and in the indapamide group. Plasma ANP concentration was significantly reduced by the treatment with captopril and benidipine but not with nilvadipine and indapamide. These results suggest that the reduction of blood pressure by the inhibition of angiotensin converting enzyme with captopril has the potential to ameliorate renal function of the SHR with remnant kidney, a model of chronic renal failure with hypertension, associated with the decreased concentration of plasma ANP. However, it remains to be determined whether the reduction of blood pressure by calcium channel blockers may be involved in the delayed progression of renal failure in this model since there were disparate effects on renal function and plasma ANP concentration with these two calcium channel blockers.     

Sensitive enzyme immunoassay for human 28 kDa calbindin-D.

A sandwich-type enzyme immunoassay for human 28 kDa vitamin D-dependent calcium binding protein (calbindin-D) was established with a sensitivity of 1 pg/tube. Antisera were generated in rabbits injected with highly purified human kidney calbindin-D, and specific antibodies to calbindin-D were purified by the use of a column of calbindin-D-coupled Sepharose. The purified antibodies showed a single band at the position corresponding to calbindin-D on an immunoblotting test with a crude extract of human kidney. The assay system consisted of polystyrene balls with immobilized F(ab')2 antibodies and the same antibodies labeled with beta-D-galactosidase from Escherichia coli. The assay was specific to 28 kDa calbindin-D, showing no cross-reactivity with other calcium binding proteins such as S-100a0 (alpha alpha), S-100b (beta beta), parvalbumin and calmodulin. The assay was also reproducible (coefficients of variation between assays were less than 10%). With the present method, immunoreactive calbindin-D could be detected in various human tissues, with major concentrations in kidney and brain. The values for immunoreactive calbindin-D in various body fluids of healthy subjects varied from undetectable in serum and semen to 3.8 +/- 2.0 (SD) micrograms/g creatinine in urine and 2.9 +/- 0.8 (SD) micrograms/l in cerebrospinal fluid. Immunohistochemically, the calbindin-D in human kidney was localized in epithelial cells of distal tubules.     

Plasma concentrations of atrial natriuretic peptide in various diseases

Using a radioimmunoassay for atrial natriuretic peptide (ANP) we studied plasma concentrations of immunoreactive ANP in order to investigate the pathophysiological role of ANP in patients with various diseases. Plasma ANP levels were elevated in patients with congestive heart failure (394 +/- 260 pg/ml, n = 8) and chronic renal failure (219 +/- 86 pg/ml, n = 11). In patients undergoing hemodialysis plasma ANP levels were markedly high and decreased after hemodialysis from 433 +/- 166 pg/ml to 204 +/- 92 pg/ml (n = 11). ANP was removed from blood to dialysate (21 +/- 13 pg/ml of dialysate, n = 6, dialysate flow: 500 ml/min). Plasma ANP level was conversely correlated with creatinine clearance (r = -0.812, p less than 0.001) in patients with renal diseases (n = 29). In patients with atrial fibrillation, pace maker implantation, lung disease, chronic glomerulonephritis, nephrotic syndrome, essential hypertension, liver disease and cerebrovascular disease, plasma ANP levels were not significantly different from those in normal subjects (70 +/- 32 pg/ml, n = 28). These results suggest that ANP may be a circulating hormone playing pathophysiological roles in congestive heart failure and chronic renal failure.     

Plasma bone Gla protein concentrations in healthy adults. Dependence on sex, age, and glomerular filtration

Plasma bone Gla protein (BGP) was determined by radio-immunoassay in 266 healthy adults, men (n = 132) and women (n = 134), aged 20-79 years. In the women aged 30-69 years, plasma BGP increased significantly with age (r = 0.44, p less than 0.001), and a particularly steep increase was seen from 1.1 +/- 0.5 (mean +/- 1 SD) in the fifth decade to 2.0 +/- 1.4 nmol/l in the seventh decade. In men, aged 30-69 years, no correlation was found between plasma BGP and age (r = -0.07, NS). Plasma bone Gla protein is removed from the circulation mainly by the kidneys and the increased plasma BGP in the women could be caused by decreased renal clearance. The interrelationship was analysed by means of partial correlation. When creatinine clearance was held constant in women, BGP still correlated positively with age (r = 0.40, p less than 0.001), but not with creatinine clearance (r = 0.003, NS) when age was fixed. Plasma BGP was significantly increased above normal in 35 patients with chronic renal failure (10.2 +/- 14.6 nmol/l). Non-linear regression analysis showed that plasma BGP was within the normal range when 24-h creatinine clearance was greater than 30 ml/min, and large increases in plasma BGP did not occur until the 24-h creatinine clearance was below 20 ml/min. We conclude that, in normal subjects and patients with mild to moderate renal failure, plasma elevations of BGP reflect increased bone turnover rather than decreased renal clearance.     

Falsely elevated plasma aldosterone concentration by direct radioimmunoassay in chronic renal failure

Plasma aldosterone concentration (PAC) in patients with chronic renal failure was measured by radioimmunoassay with and without dichloromethane extraction before the assay. Blood samples were obtained from patients with chronic renal failure who were undergoing maintenance hemodialysis, from patients with chronic renal failure who were not undergoing hemodialysis, and from age-matched normal subjects. With the three radioimmunoassay kits tested, the direct assays without extraction in normal subjects gave PAC values comparable to those obtained after the dichloromethane extraction; in contrast, in patients with chronic renal failure, the direct plasma radioimmunoassays yielded consistently higher values than those obtained after the extraction (p less than 0.001). When various plasma steroid metabolite fractions were separated by high-pressure liquid chromatography (HPLC) with a reverse-phase column, and each fraction was assayed for PAC with the three radioimmunoassay kits, high immunoreactivities were found in the polar fractions in the plasma from patients with chronic renal failure but not in normal plasma. The ratios of the immunoreactivities of these polar fractions to that of the aldosterone fraction, determined after HPLC separation, showed a significant positive correlation (r = 0.746, p less than 0.001) with serum creatinine concentrations in plasma from patients with chronic renal failure who were not undergoing hemodialysis. These results indicate that the values for PAC are falsely elevated in chronic renal failure when PAC is measured by radioimmunoassay kits without prior extraction. Furthermore, plasma from patients with chronic renal failure contains a polar substance(s) that cross-reacts with antialdosterone antibodies. This so far-unidentified substance increases with advancing renal impairment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Plasma beta-thromboglobulin and platelet factor 4 in patients with chronic renal failure and effect of hemodialysis

Significantly increased levels of plasma beta-thromboglobulin (beta-TG) (76.8 +/- 25.5 ng/ml, p less than 0.01) were observed in 24 patients with chronic renal failure (blood urea nitrogen (BUN) greater than 20 mg/100 ml), as compared with normal subjects (13.2 +/- 5.6 ng/ml). The increase in beta-TG was highly correlated with BUN (r = 0.651, p less than 0.01), creatinine (r = 0.778, p less than 0.01) and creatinine clearance ( t = -0.723, p less than 0.01). Plasma platelet factor 4 (PF4) and normal 5.0 +/- 2.0 ng/ml) also increased significantly to 8.5 +/- 3.4 ng/ml (p less than 0.01). However, statistical correlation between beta-TG and PF4 was not found in these patients. The reason is thought to be due to differences in molecular weight (PF4 8,000 MW; beta-TG 36,000 MW) and half-life time (PF4 30 min; beta-TG 100 min), and due to the difficulty in calculating statistically the correlation because of the narrow distribution of PF4 levels. The high levels of beta-TG (89.4 +/- 3.4 ng/ml) showed a further increase (109.4 +/- 5.8 ng/100 ml, p less than 0.01) after dialysis. This is thought to be due to hemoconcentration, because other blood factors such as RBC, WBC, platelets, fibrinogen, etc were elevated by about 20% during hemodialysis and because no adhesion of platelets to the cellulose membrane did occur. The increase in PF4 levels at 15 min (55.2 +/- 19.6 ng/ml, p less than 0.01) and 1 hr (23.7 +/- 8.4 ng/ml, p less than 0.01) of hemodialysis from the level before it (7.7 +/- 1.3 ng/ml) is thought to be caused the effect of heparin infusion. The change in PF4 was not accompanied by the change in beta-TG. During hemodialysis the decrease of other platelet functions such as adhesiveness, aggregation induced by ADP, collagen and PF3 remained unchanged.     

Effect of parathyroid hormone activity on gentamicin nephrotoxicity

Dietary calcium (CA++) supplementation attenuates gentamicin nephrotoxicity in rats. It has been proposed that this protective effect results from the ability of Ca++ to interfere with gentamicin binding to renal cell membranes. However, calcium supplementation also suppresses parathyroid hormone (PTH) activity, which may affect gentamicin nephrotoxicity by altering renal brush border phospholipid composition or renal calcium handling. We therefore compared gentamicin nephrotoxicity in PTH-stimulated control rats and parathyroidectomized (PTX) rats. Although their pretreatment serum ionized calcium concentration was significantly higher (1.27 +/- 0.01 vs. 0.88 +/- 0.06 mmol/L; P less than 0.001), PTH-stimulated rats had higher peak renal cortical gentamicin concentrations (543 +/- 20 vs. 395 +/- 49 micrograms/gm; P less than 0.025) and serum creatinine concentrations (3.0 +/- 0.8 vs. 0.9 +/- 0.3 mg/dl; P less than 0.05). Structural injury and depression of renal cortical slice uptake of p-aminohippurate were also less severe in PTX rats. Gentamicin treatment also caused increased urinary Ca++ excretion in control rats (from 2.12 +/- 0.64 mumol/mg creatinine per day [pretreatment] to 16.86 +/- 2.07 mumol/mg creatinine per day; P less than 0.001) but not in PTX rats. Control rats ingesting chow containing a standard Ca++ content (1.2%) resembled PTX rats. These results indicate that PTH stimulation exacerbates gentamicin nephrotoxicity. Increased peak renal cortical gentamicin concentrations in PTH-stimulated rats may be caused by increased gentamicin transport across the brush border as a consequence of PTH-mediated alteration of plasma membrane phospholipid composition, turnover, or both.(ABSTRACT TRUNCATED AT 250 WORDS)     

Different cation transport inhibitor in malignant renal hypertension and in uraemia

1. We investigated whether the previously reported circulating frusemide-like factor in rats with malignant renal hypertension was specific to this syndrome, or was also present in rats with chronic uraemia. 86Rb uptake (K+ transport) of monolayers of vascular smooth muscle cells was measured in the plasma of rats with malignant one-kidney, one-clip hypertension and of uraemic rats (60-70% nephrectomy). 2. Compared with control plasma, ouabain-insensitive 86Rb uptake of cells was reduced and ouabain-sensitive 86Rb uptake was unchanged in the plasma of rats with malignant hypertension. The reverse was found in the plasma of uraemic rats. 3. Inhibition of ouabain-sensitive 86Rb uptake of cells occurred in the plasma of rats with malignant hypertension when an angiotensin II antagonist was added to the reaction mixture. 4. The findings confirm the presence of a frusemide-like plasma factor in malignant hypertension and a ouabain-like plasma factor in uraemic. The presence of a ouabain-like plasma factor in malignant hypertension is camouflaged by an elevated circulating angiotensin II level, which stimulates K+ transport.     

Evidence of oxidative stress in the renal cortex of diabetic rats: favourable effect of vitamin E

The aim of this study was to determine whether there are any disturbances of red/ox balance in the renal cortex of rats during the course of experimental diabetes. In the renal cortex of rats with streptozotocin-induced diabetes, the activity of superoxide dismutase (SOD) isoenzymes, glutathione peroxidase (GSH-Pox), glutathione S-transferase (GST) and glutathione reductase (GSH-RED) was measured in the 5th, 10th and 15th weeks of diabetes. Free radical cell damage was assessed on the basis of malonyldialdehyde (MDA) concentration. The influence of lipophilic antioxidant vitamin E on these analytes was also studied. An increase in MDA concentration in the 10th and 15th weeks of diabetes correlated significantly with plasma glucose concentration (r = 0.47; p < 0.001). Moreover, MDA concentration was influenced by time (+); p < 0.001, diabetes (+); p < 0.001, vitamin E (-) p < 0.001 (ANOVA). Plasma creatinine concentration in rats was elevated by diabetes (p < 0.001), whereas vitamin E decreased the concentration (p < 0.05). Vitamin E lowered the activity of GSHPox (p < 0.001) and GST (p < 0.01) (ANOVA). Our results indicate that during experimental diabetes, disturbances of red/ox balance lead to disturbance in renal function manifested as increased creatinine blood concentration. We suggest that oral supplementation of vitamin E protects the renal cortex of rats during experimental diabetes.     

Red blood cell calcium level in chronic renal failure: effect of continuous ambulatory peritoneal dialysis

Red blood cell (RBC) calcium, calcium 45 influx, and calcium extrusion as indicated by Ca-stimulated, Mg-dependent adenosine triphosphatase (CaATPase) was determined in patients with chronic renal failure (CRF), patients with CRF receiving continuous ambulatory peritoneal dialysis (CAPD) treatment, and controls. Cell calcium, which in the controls was 5.5 mumol/L of cells, was elevated in patients with CRF--30.6 +/- 6.8 mumol/L of cells (p less than 0.002)--and in patients receiving CAPD-23.6 +/- 6.7 mumol/L of cells (p less than 0.02). Basal CaATPase activity in controls was 850.7 +/- 66.7 nmol inorganic phosphate per milligram of protein per hour. It was suppressed in patients with CRF and patients receiving CAPD: 504.9 +/- 34.4 nmol inorganic phosphate per milligram of protein per hour and 618.2 +/- 47.3 nmol inorganic phosphate per milligram of protein per hour, respectively (p less than 0.01). Calmodulin-stimulated CaATPase revealed a pattern similar to that of CaATPase basal activity. RBC calcium showed an inverse correlation with CaATPase activity (r = -0.935, p less than 0.005) in patients with CRF. Calcium influx was increased in patients with CRF and in patients receiving CAPD: 12.00 +/- 1.34 mumol/L of cells per hour and 13.60 +/- 1.70, respectively, compared with 4.61 +/- 0.39 mumol/L of cells per hour in controls (p less than 0.001). Patients with CRF have elevated RBC calcium levels mainly related to decreased extrusion and to increased influx. CAPD fails to improve substantially these abnormalities. Plasma vanadium levels were markedly elevated in patients undergoing hemodialysis and marginally in patients receiving CAPD.(ABSTRACT TRUNCATED AT 250 WORDS)     

Red blood cell calcium homeostasis in patients with end-stage renal disease

Low cell calcium level is essential for preservation of red blood cell (RBC) membrane deformability and survival. RBCs from patients with end-stage renal disease (ESRD) demonstrate reduction in membrane deformability, possibly as a result of increased RBC cellular calcium level. To evaluate calcium homeostasis in RBCs from patients with ESRD, we measured cell calcium level, basal and "calmodulin"-stimulated calcium-stimulated Mg-dependent ATPase (CaATPase) activity, and calcium 45 efflux were measured before and after hemodialysis. The in vitro effect of uremic plasma and of urea on CaATPase activity of normal RBCs was tested, and 45Ca influx into RBCs of patients undergoing hemodialysis also was determined. A morphologic evaluation of red cells from patients with ESRD was performed with a scanning electron microscope. RBC calcium level in patients (mean +/- SEM 21.2 +/- 2.8 mumol/L of cells; n = 28) was higher than in controls (4.9 +/- 0.3 mumol/L of cells; n = 24; p less than 0.001). Hemodialysis had no effect on cell calcium level. Both basal and "calmodulin"-stimulated RBC CaATPase activities in patients with ESRD (n = 9) were reduced by approximately 50% (p less than 0.01), but after hemodialysis, enzyme activity returned to normal. 45Ca efflux from calcium-loaded cells, which was 2574.0 +/- 217.0 mumol/L of cells per 0.5 hours before hemodialysis, increased to 3140.7 +/- 206.8 mumol/L of cells per 0.5 hours after hemodialysis (p less than 0.005). In vitro incubation of normal RBCs with uremic plasma depressed CaATPase activity, but incubation with urea had no effect. RBCs of patients with ESRD revealed increased 45Ca influx, 7.63 +/- 1.15 mumol/L of cells per hour versus 4.61 +/- 0.39 mumol/L of cells per hour (p less than 0.025). RBCs of patients revealed a high incidence of spherocytosis and echynocytosis, which correlated with a high cell calcium level (r = 0.894, p less than 0.01). These results indicate that RBC calcium level is elevated in patients with ESRD and suggest that a dialyzable uremic factor inhibits RBC CaATPase activity and thereby calcium efflux, which may account for the elevated cell calcium level. The increased calcium influx further increases cellular calcium level. These abnormalities are associated with spherocytosis and echynocytosis and may contribute to the shortened survival of RBCs in uremia.     

Association between increased atrial natriuretic peptide and reduced cisplatin nephrotoxicity in rats.

Plasma atrial natriuretic peptide (ANP) concentrations were monitored in two experimental models of protection from cisplatin nephrotoxicity. Sprague-Dawley rats made diabetic with streptozotocin (65 mg/kg) were protected from cisplatin-induced nephrotoxicity when compared to control rats as indicated by reduced plasma creatinine (0.49 +/- 0.02 vs. 0.9 +/- 0.06 mg/dl; P less than .001) and blood urea nitrogen concentrations (18.51 +/- 1.4 vs. 43.08 +/- 2.1 mg/dl; P less than .001). Plasma ANP was also increased with experimental diabetes (76.5 +/- 8.98 fmol/ml) vs. normoglycemic controls (43.8 +/- 8.9 fmol/ml; P less than .02). When diabetic rats were treated with insulin, the renal protection observed with the diabetic state was reversed (creatinine, 0.70 +/- .05 mg/dl); plasma ANP concentrations were also reduced (52.2 +/- 15.2 fmol/ml). Renal platinum concentrations were significantly lower in the diabetic group and the reversal of diabetic-induced renal protection with insulin was associated with increased renal platinum concentrations. In rats given a single i.p. dose of cisplatin (5 mg/kg), a reduction in cisplatin-induced nephrotoxicity was observed when 5% NaCl was the vehicle of choice compared to that seen in rats given the same dose of drug in 0.9% saline (creatinine, 0.43 +/- 0.07 with 5% NaCl vs. 0.63 +/- 0.03 with 0.09% NaCl). NaCl (5%) administration also resulted in increased plasma ANP concentrations when compared to rats receiving equivalent volumes of 0.9% NaCl (88.4 +/- 6.2 vs. 50.5 +/- 5.6 fmol/ml, respectively). These data suggest that increased endogenous ANP may be a mechanism of renal protection common to both experimental diabetes and hypertonic saline administration. Chronically increased ANP may prevent renal accumulation of platinum in the kidney.     

Plasma calcitonin in chronic renal failure: relation to other factors of importance in bivalent ion metabolism.

1. Plasma concentrations of human calcitonin were measured in groups of patients with chronic renal failure, treated either conservatively or by haemodialysis, and compared with a normal group of persons. 2. Plasma calcitonin was statistically significantly elevated in both groups with renal failure. 3. When the data from the three groups were pooled, plasma calcitonin was found to be inversely correlated with total calcium and directly correlated with plasma creatinine.     

Seasonal variation of serum bone GLA protein

The seasonal variation of serum Bone Gla Protein (BGP) was investigated in 15 normal young individuals (seven women and eight men, aged 27-39 years). Serum BGP exhibited a significant seasonal variation of 23% around the yearly mean (p less than 0.001) with zenith in February and nadir in July. Significant seasonal variations were noted also for serum alkaline phosphatase (p less than 0.01) and serum phosphate (p less than 0.01). Serum calcium, bone mineral content (BMC) and creatinine clearance revealed no significant seasonal variation. The seasonal variation of BGP did not follow the variation in serum total alkaline phosphatase. The seasonal variation of BGP has to be taken into account when using the protein as a marker of bone remodelling activity. The variation was probably caused by changes in the production rate of the protein, since the renal excretion of the protein, as reflected in creatinine clearance, remained unchanged throughout the year.     

The course of chronic kidney failure during acetate and bicarbonate hemodialysis]

In patients with chronic renal failure (CRF) given acetate (n = 55) and bicarbonate (n = 45) hemodialysis, the dynamics of the progress of uremia symptoms estimated in marks, the index of the lean body weight, the rate of urea generation, the magnitudes of the dialysis indices according to creatinine and urea, TACur and TADur were studied on a monthly basis for many years. The actual survival rates were calculated. It has been demonstrated that as compared to acetate hemodialysis, in patients on bicarbonate hemodialysis, the progress of uremia symptoms is significantly decelerated (p less than 0.05) and hypercatabolism of proteins is decreased by the 4th year of the observation period. This enhances the patients' medical rehabilitation and noticeably increases the actual survival of the patients (p less than 0.001). Advantages of the treatment of CRF patients by bicarbonate hemodialysis are under discussion.     

Plasma noradrenaline in Goldblatt models of renovascular hypertension in the rat, before and after surgical reversal

Plasma noradrenaline (NA), blood pressure (BP) and heart rate (HR) were measured simultaneously in conscious rats under basal conditions in the early phase (4-6 weeks) of one-kidney, one-clip hypertension (1K1C), in the early (4-6 weeks) and chronic (greater than 16 weeks) phases of the two-kidney, one-clip model (2K1C) and in age-matched loose clip control animals before and 2 days after unclipping. The elevated BP in all three hypertensive groups fell to normal after unclipping, whereas removal of the constricting clip in loose clip controls had no effect on BP. Plasma NA was elevated in 1K1C hypertension (P less than 0.05) and fell slightly but non-significantly on unclipping. However, in the early phase of 2K1C hypertension plasma NA was unaltered before and rose significantly (P less than 0.05) after unclipping. Plasma NA did not change with unclipping in the chronic phase of 2K1C hypertension and was not different from controls. Unclipping loose clip control animals produced no change in plasma NA. Changes in HR on unclipping followed a similar pattern to changes in plasma NA: changes in the two variables were significantly correlated in all three models (1K1C: r = 0.61, P less than 0.005; early 2K1C: r = 0.45, P less than 0.05; chronic 2K1C: r = 0.62, P less than 0.01). However, BP was only correlated with plasma NA in 1K1C hypertension (r = 0.49, P less than 0.02) and not in either phase of the 2K1C model. There was also a highly significant correlation between HR and plasma NA in 1K1C hypertension (r = 0.71, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Untoward effects of chronic dual renin-angiotensin system blockade: influence of previous chronic renal failure

Dual blockade of the renin-angiotensin system (RAS) has increased antiproteinuric effects and so a higher incidence of secondary effects can be expected when this kind of treatment is administered. The aim of this study was to assess the safety of dual blockade of RAS. Seventy-five (54 men and 21 women) patients has been treated in our unit with dual RAS blockade due to proteinuria higher than 1 g/24 h. Mean age was 57.1 +/- 14.0 years. Fifty-three patients had chronic renal failure (CRF) at baseline. Analytical data of 6 months visit and last follow-up visit were recorded. A small reduction of systolic blood pressure and diastolic blood pressure was observed in both treatment groups throughout the study. Neither the CRF patients nor those with normal renal function showed any reduction in mean plasma haemoglobin levels, but differences between groups were significant at the second and third visits (anova). No change was detected in haematocrit. Mean K+ significantly increase at the second visit in the CRF group (from 4.80 +/- 0.64 to 5.23 +/- 0.81 mmol/l, p < 0.001, Student's t-test). There were no changes in normal kidney function group (4.58 +/- 0.37 vs. 4.63 +/- 0.44). At baseline plasmatic creatinine was higher in the CRF group (2.09 +/- 0.60 0.20 mg/dl vs. 0.99 +/- 0.20 mg/dl, p < 0.001, Student's t-test) and creatinine clearance was lower (48.6 +/- 20.7 ml/min vs. 107.0 +/- 0.30 ml/min, p < 0.001, Student's t-test). There was a small increase in creatinine along the follow-up when compared with the normal renal function group (p < 0.001, anova). Conversely, creatinine clearance remain unchanged in the normal renal function group, and there was a decrease in creatinine in CRF patients (p < 0.001). Dual RAS blockade seems to be safe in renal patients even when mild to moderate renal failure is present. Severe hyperkalaemia is uncommon. Small increments in plasmatic creatinine can be seen but they are hardly dangerous. Combined treatment does not significantly influence erythropoiesis.     

Intra-individual variation of some analytes in serum of patients with chronic renal failure

Biological intra-individual variation in the concentration of 15 biochemical analytes in serum was estimated for 17 patients with chronic renal failure (CRF) and compared with results for apparently healthy individuals. The ratio of the average intra-individual variation in CRF patients to that in normal subjects was 1.5 to 2.0 for sodium, chloride, calcium, and creatinine; 1.2 to 1.5 for hemoglobin, total protein, albumin, globulin, uric acid, cholesterol, and alpha-amylase. The intra-individual CVs for urea, high-density-lipoprotein cholesterol, triglycerides, and alkaline phosphatase did not differ significantly between groups. The intra-individual variation of calcium and the concentration of creatinine in serum correlate significantly (r = 0.661, p less than 0.01). Individual values showed a gaussian distribution for all analytes. There was no time dependence of the intra-individual variation during a three-week interval, except for calcium and cholesterol. The estimated biological component of intra-individual variation and the analytical variation can be used to derive decision-making criteria in monitoring CRF.     

尿毒净液延缓慢性肾功能衰竭的机理探讨

目的:研究尿毒净液对5/6肾切除鼠慢性肾功能不全模型的疗效及其作用机理。方法:建立5/6肾切除大鼠慢性肾功能不全模型,观察12周内尿毒净液和洛丁新对尿素氮、肌酐、24h尿蛋白量及肾小球平均截面积的影响。结果:尿毒净液组和洛丁新组尿素氮、肌酐明显低于对照组,尿蛋白量低于对照组,尿毒净液组肾小球平均截面积均显著低于模型对照组和洛丁新组。结论:尿毒净液能改善5/6肾切除大鼠的肾功能。