[Validity of iohexol clearance in patients with chronic renal failure and normal renal function in comparison to (99m)Tc-DTPA-clearance]

BACKGROUND AND OBJECTIVE

The most common method used for testing dynamic renal function is creatinine clearance, but it has some limitations, e. g. variable muscle mass and tubular secretion of creatinine. The use of radionuclides as an exact method is limited in terms of availability, cost and time needed for examination. We compared the plasma clearance of iohexol with the established (99m)Tc-diethylenetriaminepentaacetate acid (DTPA) clearance. The aim of the present study was to validate iohexol clearance as a simple and suitable method for measuring to determine GFR with a comparable sensitivity to radioisotopic methods.

METHODS

120 patients (49 females, 71 males), mean age of 56 (range 20 to 84) years with normal renal function and different stages of renal failure, mean creatinine clearance of 61.6 +/- 44,9 (range 1.8 - 181.1) ml/min/1.73 m2 received a bolus injection of 10 ml iohexol, a non-ionic low osmolar x-ray contrast medium. Using the one-compartment model, plasma samples were taken after 150, 240 and 480 minutes. The total plasma disappearance of iohexol was measured by x-ray fluorescence analysis and the clearance was calculated. The (99m)Tc-DTPA clearance was determined in accordance with a standard protocol.

RESULTS

A high correlation was found between the clearance of iohexol and (99m)Tc-DTPA (r = 0.95). The average deviation between Iohexol and (99m)Tc-DTPA clearance was 7.4 ml/min/1.73 m2. Allergic and nephrotoxic side effects were not observed.

CONCLUSION

Iohexol clearance is a valid method for measuring GFR in patients at any stages of renal failure. It is easy to perform and inexpensive.

The effects of prolonged physical exercise on renal function, electrolyte balance and muscle cell breakdown

BACKGROUND

Postexercise proteinuria, hematuria and changes in serum electrolyte balance as well as increased levels of plasma indicators for muscle leakage are believed to be transient and of benign character.

METHODS

A group of 51 healthy athletes took part in a 100 km race over 14.25 hours. All of them had to reach the finish together. Urine and blood samples were collected before (a) and immediately after running (b) as well as 6 hours after the race (c).

RESULTS

The serum concentrations of potassium (4.8 +/- 0.5 (a) vs. 4.0 +/- 0.3 (c) mmol/l), protein (73.1 +/- 5.2 (a) vs. 71.1 +/- 3.9 (c) g/l) and albumin (44.0 +/- 2.85 (a) vs. 42.9 +/- 2.8 (c) g/l) decreased significantly (p < 0.0001, p < 0.05, p < 0.05, respectively) but remained within physiological ranges. The serum sodium concentration decreased immediately after the race (136.9 +/- 4.5 (a) vs. 131.1 +/- 2.4 (b) micromol/l, p < 0.0001). The fractional sodium excretion decreased 6 hours, but not immediately after the race (0.78 +/- 0.59 (a) vs. 0.48 +/- 0.82 (c), p < 0.05). Myoglobin (31.8 +/- 6.9 (a), 291.5 +/- 197.2 (b) and 182.2 +/- 135.3 (c) microg/l, p < 0.0001) and creatine kinase (1.13 +/- 0.45 (a), 10.76 +/- 6.9 (b) and 9.46 +/- 15.5 (c) pmol/l, p < 0.0001) increased dramatically. Troponin I was also significantly increased at finish (0.0186 +/- 0.0121 (a) vs. 0.0213 +/- 0.0165 (b) ng/ml, p < 0.05) and positively correlated with myoglobin and creatine kinase, but remained far below the pathologic range. Serum creatinine and urea remained almost unchanged. Glucosuria and hematuria occurred 6 hours after the run in 9.1% and 6.8%, respectively. The erythrocytes examined by phase-contrast microscopy were not damaged in terms of dysmorphic cells. Glomerular-type proteinuria was found in 11.4% of the participants 6 hours after the race.

CONCLUSIONS

We conclude that long lasting, mild exertion is harmless for renal function, electrolyte balance and skeletal muscle as well as myocardial metabolism in healthy persons.

Liver function after bilateral nephrectomy

Consequences of bilateral nephrectomy (NX) for liver functions and for hepatic excretion of various endogenous substances were characterized in rats 24 h after NX. Plasma concentrations of urea, creatinine, fibrinogen, and glutathione increased significantly after NX, whereas the concentrations of total protein, albumin, and lipids decreased. The hepatic excretion of urea, creatinine, phospholipids, cholesterol, and aldosterone significantly increased in uremia, and excretions of protein and glutathione diminished. Active biliary transport can be diminished after NX by the effects of uremic toxins on the liver cells or by the competition phenomena between endogenous substances, which are normally excreted in urine, at the hepatocellular level. Reduced glutathione content and increased lipid peroxidation in hepatocytes have been found. Changes in lipid and protein metabolism after NX can be proved.

Determination of enzyme activities in serum for the detection of xenobiotic effects on the liver

The determinations of enzyme activities in the serum are of considerable importance in detecting xenobiotic effects on the liver. After a brief introduction to the basics of enzyme diagnostics, the enzymes ALAT, ASAT, ICDH, LDH, SDH, GLDH, AP, gamma-GT, CHE are characterized with regard to their occurrence, their half-life periods in the serum and their clinical value. They are followed by enzyme levels and the presentation of the dynamics of enzyme activities in the serum after xenobiotic influences on the liver in humans.

The influence of selected urinary constituents on the adhesion process of Escherichia coli to human uroepithelial cells

In the pathogenesis of infectious diseases, great importance is attached to the problem of adhesion of bacteria to cells. In 100 urine specimens from normal test persons, patients with infections of the lower urinary tract, with chronic pyelonephritis and glomerulonephritis were studied. The adhesion of strains of Escherichia coli to human uroepithelial cells depended on the concentration of single urinary factors. While increased concentrations of urea and creatinine favored the adhesion process, a statistically significant negative influence was found with regard to potassium, immunoglobulins and pH value. Considering the multifactorial effects of the urinary constituents, we found in a multivariate comparison that none of the studied physiological features alone exerts a fundamental influence upon adhesion, but in their entirety they determine the environmental conditions for the adhesion of bacteria to cells in the urine.

[Significance of parathyroid hormone (PTH) within the scope of central nervous system disorders in hemodialysis patients]

The role of PTH as possible uraemic toxin within the scope of disturbances of the central nervous system (progressive dialysis encephalopathy, PDE) was investigated in 88 patients undergoing haemodialysis. A radioimmunoassay covering the C-terminal PTH fragment was used. Patients undergoing haemodialysis with a PDE showed the highest values with 2,015.4 +/- 457.9 pg/ml, and also in the preclinical stage of a PDE the PTH values with 1,845.7 +/- 663.1 pg/ml lay significantly above those ones of the patients undergoing haemodialysis without PDE (794.8 +/- 364.7 pg/ml). The findings speak for the importance of PTH in the development of complications of the central nervous system within the scope of the uraemia syndrome.

[Morphometric and histochemical studies of the skeletal muscles of patients with chronic renal failure and dialysis patients]

In 19 patients with chronic renal insufficiency in the stage of compensated retention, 20 patients undergoing dialysis and 24 patients with normal renal function muscle tissue was taken by an open biopsy and investigated histologically, histochemically as well as morphometrically. A neurogenic atrophy stood in the foreground of the histologic changes of the striated musculature in uraemia, a pure type II atrophy was found more infrequently. In the patients undergoing dialysis frequency and size of these disturbances were more distinct. Except for a possible influence of a disturbed calcium metabolism other pathogenetic factors supposed in literature could not be found.

No tissue level abnormality of vitamin A concentration despite elevated serum vitamin A of uremic patients

In 57 patients with chronic renal failure (CRF) [44 patients on regular dialysis treatment (RDT), 33 renal transplant patients (RT) and 26 normal patients (NP)] and in a further 11 patients with CRF (8 patients on RDT and 17 patients without any renal disease in the post mortem) the vitamin A content of the serum obtained from the tissue of the liver, the stomach, the subcutaneous adipose tissue and the bone were analyzed. The vitamin A content of the serum was increased significantly for all groups of patients in comparison with the control group, but hypervitaminotic ranges were not reached in any case. The vitamin A content decreased depending on the time of dialysis treatment and the period after kidney transplantation. The retinol-binding protein accumulated even more than vitamin A in CRF and RDT. This statement is not in conformity with that of a hypervitaminosis A, of which normal respectively decreased RBP levels are characteristic. The serum prealbumin concentration was near the upper limit of the normal range in all groups of patients. The serum content of beta-carotene in patients with CRF and RDT was raised in comparison with NP and RT patients. As to the vitamin A content of the organs, a distinctive decrease appeared in the liver, so that a marginal supply must be assumed. In the stomach and the subcutaneous adipose tissue no changes, in comparison with the control patients, resulted. Due to renal insufficiency the results indicated an unphysiological situation in the vitamin A metabolism. Connections with disturbances of the fat-household could not be set up.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal effects of aluminium in uraemic rats and in rats with intact kidney function

The effect on renal function following administration of aluminium (i.p., five times weekly (0.05 or 0.5 mg kg-1 body weight) for 12 weeks) to partially nephrectomized (5/6 NX) or intact female rats was examined. The observed loss of concentrating ability, characterized by increased urine volume and an increased sodium excretion, as well as increased renal excretion of p-aminohippurate (demonstrable after low-dose treatment with nephrotoxins) can be interpreted as an initiation of kidney function injury. No distinct differences in response were observed between partially nephrectomized and intact animals.

[Vitamin A status of patients with chronic renal failure in relation to renal osteodystrophy]

In patients with chronic renal insufficiency and dialysis patients as well as in normal persons determinations of vitamin A in the serum and in the bone were performed and related to the parameters of the bone metabolism and to the histomorphometric investigation of the bone. The vitamin A serum levels were significantly increased in the two groups of patients, however, did not show any differences between the patients with an osteoidosis or the combination of osteoidosis and fibroosteoclasia. There were no correlations to calcium, phosphorus, PTH and to the alkaline phosphatase as well as to the individual histomorphometric data. The vitamin A content of the bone was low and did not show any differences to the normal persons. On the other hand, there were significant relations between the parathormone and the parameters of the regeneration and the absorption of the bones. An additional influence of vitamin A on the bone disturbance, eventually by the activation of the osteoclasts cannot be excluded.

Pharmacokinetics and pharmacodynamic effects of furosemide in patients with liver cirrhosis

Ten patients with compensated cirrhosis of the liver, 7 patients with portal decompensated cirrhosis of the liver and 10 patients with intact liver function were investigated. After intravenous injection of 40 mg furosemide elimination half-life, total and excretory clearance were not significantly different in the 3 groups investigated, but renal clearance was enhanced in the 2 cirrhosis groups and nonrenal clearance diminished in patients with decompensated cirrhosis of the liver. In those patients distributional volumes were significantly higher than in the control group. According to the increased urinary excretion of unchanged furosemide in patients with cirrhosis of the liver, the pharmacodynamic effect of the drug is enhanced: In the first 4-h-collecting period the excretion of water, chloride and sodium is significantly more increased than in the control group. After a period of 24 h this effect is still noticeable. The effect of furosemide on the excretion of potassium, creatinine and urea nitrogen is not significantly influenced by liver disease. Doubling the dose from 40 to 80 mg furosemide did not enhance the diuretic effect of the drug despite the doubled urinary excretion of unchanged furosemide.

Pharmacokinetic and pharmacodynamic effects of furosemide in patients with impaired renal function

Three groups of patients with kidney diseases were investigated: I. creatinine in serum less than 100 mumol/l, II. creatinine in serum 100-250 mumol/l, III. creatinine in serum greater than 250 mumol/l. After intravenous injection of 40 mg and 80 mg furosemide, serum concentrations and urinary excretion of the unchanged drug were measured fluorometrically. Moreover, urinary excretion of water, electrolytes, creatinine and urea nitrogen were estimated in order to check the pharmacodynamic effect of the drug. The pharmacokinetic parameters calculated were similar in group I and II. In group III t 1/2 was prolonged, renal clearance of furosemide was diminished. The diuretic effect of furosemide was noticeable during the first 4 hours following the injection of 40 mg in all 3 groups. Doubling the dose did not enhance the effect. Creatinine and urea nitrogen excretion in urine were not influenced by furosemide.

[Furosemide effects in patients with chronic renal insufficiency]

In 8 patients with a slight restriction of the renal function (serum creatinine 150-300 mumol/l), 10 patients with a severe restriction of the renal function (serum creatinine greater than 300-1,200 mumol/l) and in 10 control persons with intact renal function on 2 subsequent days after 40 and 80 mg furosemide the pharmacokinetic data were calculated intravenously from the course of the serum concentration and the renale excretion as well as pharmacodynamic parameters. In comparison to the control persons in patients with creatinine values of more than 200 mumol/l still 4 hours after intravenous injection furosemide could be proved in the serum. According to this the excretion of the unchanged furosemide was clearly decreased in the 24-hour-urine. In decreased renal clearance of furosemide the elimination half-life period was prolonged. In all three groups of patients the diuretic effect of furosemide was very distinctly marked in the first four hours after injection of 40 mg, a doubling of the dose did not increase this effect. Only in the first four hours also an increased excretion of sodium, chloride and calcium occurred; in the 24-hour-collection period no differences between the three groups were the result. The excretion of creatinine and urea-N in the urine was not influenced by furosemide. Thus also in the chronic renal insufficiency there is the indication of the furosemide therapy only then, when the extracellular space or the intravasal volume are enlarged. As individual dose 40 mg are recommended intravenously.

Long term toxicological studies on the progestin STS 557

The toxicity of 17 alpha-cyanomethyl-17 beta-hydroxy-estra-4, 9-dien-3-one (STS 557) was studied by its oral administration of 0.1, 1.0 or 10.0 mg/kg/day to Wistar rats for six months, and of 0.01, 0.1 or 1.0 mg/kg/day to beagle dogs for six months, respectively. Levonorgestrel at a dose of 1.0 mg/kg/day was used as the standard in the dog study. With respect to the progestational activity of the compound the main target organs were the hypophysis, the reproductive organs and the adrenals. Mammary hyperplasia was observed in dogs treated with STS 557 or levonorgestrel at the dose of 1.0 mg/kg/day, but in no case mammary nodules could be detected. At the dose of 1.0 mg/kg/day STS 557 and levonorgestrel were found to increase the plasma insulin response to i.v. glucose in bitches, but neither the mean blood glucose levels nor the glucose utilization were affected. Moreover, during administration of both steroids to dogs temporary changes in serum concentrations of triglycerides and total cholesterol were noted. The results obtained in rats and dogs from functional and morphological investigations did not reveal any toxic side effects of STS 557 on the liver, the kidneys, the bone marrow or on blood coagulation. The effects on the reproductive organs observed following STS 557 especially in dogs are related to both the hormonal effects of the compound and the specific response of the dog to potent progestagens.

Influence of hemoperfusion with XAD-4 resin on the concentration of biologic constituents in the blood

13 patients, who had been subjected to hemoperfusion with Amberlite XAD-4 resin (Haemoresin, Fa. Braun), because of acute intoxications, were examined for the adsorption of bioactive material from the blood. A mean treatment period of four hours at a blood flow rate of 200 ml/min. resulted in a marked thrombocyte decrease by 43% and changes in the concentrations of proteins, complement components C3 and C4 (16-26%) triglycerides (33%), aldosterone (33%) and testosterone (20%). Low molecular weight substances and electrolytes, however, were only slightly or not affected. Thus hemoperfusion system with its poor biocompatibility and inability to remove BUN, electrolytes and water is only suitable for short-term treatment and cannot be used without detailed control of possible side effects and perhaps substitution for treatment of chronic renal or hepatic failure. Hemoperfusion has proved an efficient method of treating various exogenous intoxications. The adsorption of biologically active material from the blood constitutes several side effects which contraindicate long-term treatment, above all of endogenous intoxications such as chronic renal failure and hepatic failure. With the type of adsorber used - various charcoal preparations, resins etc. such as uncoated material or coated with different substances - these side effects vary and have not yet been investigated in a systematic, comparative and comprehensive way. The present investigations are meant to check the adsorption behaviour of Amberlite XAD-4 Resin in vivo towards some selected blood constituents and the influence of hemoperfusion on the concentrations.

[The effect of hemoperfusion with XAD-4 resin on biological constituents of the blood]

13 patients who had undergone a haemoperfusion therapy with Amberlite XAD-4 resin (Haemoresin, Braun, F.R.G.) because of acute intoxication were examined for adsorption of biological material from the blood. Treatment lasting on average 4 hours at a blood-circulation rate of 200 ml/min resulted in a 43% reduction of thrombocytes and in changes in the concentrations of proteins, complement factors, triglycerides, aldosterone and testosterone. Low-molecular substances and electrolytes were however, except for sodium, only slightly influenced. Thus this haemoperfusion system is only suitable for shortterm application and cannot be used without substitution for chronic treatment of terminal renal insufficiency.