Good biocompatibility of the polyamide hemofilter

Chronic hemofiltration (HF) is now a well-established method, especially for elderly uremic patients and those suffering from cardiovascular problems. This is due to the fact that chronic HF offers superior treatment comfort with less hypotensive episodes, vomiting, muscle cramps and febrile reactions. Apart from the different blood purification techniques involved in chronic HF compared to hemodialysis (i.e. convection versus diffusion), it might well be that the better treatment comfort is attributable to a certain extent to the polyamide HF membrane used in our HF treatments. We studied different biocompatibility parameters and received the following data: (a) leukocytes and thrombocytes remained unchanged during a treatment session; (b) elastase increased slightly but there was no difference between the polyamide and polycarbonate membrane, and (c) arterial and venous concentrations of C5a and C3d remained almost unchanged. The superior treatment comfort and better vascular stability of HF over hemodialysis might also be due to the improved biocompatibility of the applied hemofilter as the polyamide membrane induces no changes in different biocompatibility parameters such as leukocytes, thrombocytes, C5a or C3d.

[Balloon dilatation in unstable angina pectoris and acute myocardial infarct]

Early results after percutaneous transluminal coronary angioplasty (PTCA) in patients with unstable angina or acute myocardial infarction were compared with those in patients with stable angina. The primary success rate in 115 patients with unstable angina was 72%, in 73 with acute myocardial infarction 78%, and in 213 with stable angina 79%, i.e. there was no difference between the three groups. In patients with acute myocardial infarction and primary successful PTCA control angiography was performed one month after PTCA, in patients with unstable and stable angina 6 months after PTCA. Angiographic findings were identical in the three groups. But the results after successful balloon dilatation were dependent on the extent of primary success: in all three groups, patients in whom the post-dilatation control angiography revealed recurrence of stenosis the primary results were worse than in those without. There was no difference between those patients with lasting success and those with recurrence as regards cholesterol level, arterial hypertension, diabetes, and smoking habits. It is concluded that in every patient with acute symptoms of coronary heart disease the indication for PTCA should be considered.

Iron overload, but not treatment with desferrioxamine favours the development of septicemia in patients on maintenance hemodialysis

During a 19-month period we determined the incidence of bacterial infection among 39 patients treated with desferrioxamine who had end-stage renal disease and were undergoing maintenance hemodialysis. Twenty-three received desferrioxamine because of aluminum-related bone disease, and 16 because of iron overload. A control group of 193 patients on maintenance hemodialysis but without desferrioxamine was used. No difference was found in the incidence of septicemia or of all bacterial infections between the patients with aluminum-related bone disease treated with desferrioxamine and the control patients (0.12 vs. 0.12 septicemia per patient-therapy-year, p greater than 0.05; 0.23 vs. 0.26 bacterial infections per patient-therapy-year, p greater than 0.05). The incidence of septicemia in patients treated with desferrioxamine for iron overload, however, was almost three times that in the control patients (0.36 vs. 0.12 septicemia per patient-therapy-year, p less than 0.01). To assess the effect of iron overload itself, we determined the frequency of bacterial infection in patients on regular hemodialysis who have never received desferrioxamine. These were subdivided into three groups according to serum ferritin level which indicated normal or low iron stores (Group I: serum ferritin 10-330 micrograms/l, n = 125), moderate (Group II: serum ferritin 331-1000 micrograms/l, n = 49) or more advanced iron overload (Group III: serum ferritin 1001-2000 micrograms/l, n = 10). Compared to patients with normal or low serum ferritin levels (Group I), we found a significantly higher rate of bacterial infection among patients in Group II compared with Group I (0.18 vs. 0.34 infections per patient-therapy-year, p less than 0.05) and Group III compared with Group I (0.18 vs. 0.58 infections per patient-therapy-year, p less than 0.01). These results suggest that treatment with desferrioxamine does not favour the development of septicemia or bacterial infection independently of iron overload and that iron overload itself may predispose patients on regular hemodialysis to bacterial infection.

Unintentional Weight Loss in Chronic Hemodialysis Patients - A Diagnostic Dilemma

Reasons for an unintentional weight loss were investigated in a retrospective study of 26 (13.5%) patients who, out of 192 patients, had revealed a continuous linear weight loss of more than 4 kg since commencing hemodialysis treatment. The investigated serum parameters were not indicative, nor were the regularly performed tuberculin tests and the computer tomography helpful for the diagnosis. However, from the analysis of the causes for hospital admission it appears that hemodialysis patients with wasting suffer especially frequently from a sepsis. Physicians should be aware of this complication which induces further body weight loss.

Unintentional weight loss in chronic hemodialysis patients--a diagnostic dilemma

Reasons for an unintentional weight loss were investigated in a retrospective study of 26 (13.5%) patients who, out of 192 patients, had revealed a continuous linear weight loss of more than 4 kg since commencing hemodialysis treatment. The investigated serum parameters were not indicative, nor were the regularly performed tuberculin tests and the computer tomography helpful for the diagnosis. However, from the analysis of the causes for hospital admission it appears that hemodialysis patients with wasting suffer especially frequently from a sepsis. Physicians should be aware of this complication which induces further body weight loss.

Renal osteodystrophy in asymptomatic hemodialysis patients: evidence of a sex-dependent distribution and predictive value of serum aluminum measurements

Bone histologies and serum concentrations of calcium, phosphate, alkaline phosphatase, iPTH, 25 OHD, 1,25(OH)2D3, and aluminum were obtained from 113 chronically hemodialyzed patients free of symptoms and signs of renal osteodystrophy. All patients had a pathologic bone histology; in 69.0%, a mixed form with predominant osteitis fibrosa and concomitant osteoidosis. In 30.1%, we found pure hyperosteoidosis, nearly half of these cases showing osseous aluminum deposits. Hyperosteoidosis was much more frequent in women (35.7%) than in men (20.9%), although the prescribed intake of aluminum-containing phosphate binders was the same. It is possible that female hemodialysis patients were more prone to aluminum accumulation or that they had a better compliance in taking the aluminum hydroxide. Serum parameters alone were not very helpful in predicting the underlying bone disease. Mean iPTH concentrations tended to be lower in the patients with hyperosteoidosis than in those with the mixed lesion, but there was wide variation. Serum aluminum was only predictive for aluminum deposits in the bone when concentrations exceeded 100 micrograms/L.

The occurrence of fever during hemodialysis and hemofiltration. A comparative study

The occurrence of fever during various blood purification methods was evaluated in a retrospective study. It could be demonstrated, that patients treated chronically by conventional hemodialysis experience six times more febrile episodes than patients on chronic hemofiltration (4.84% versus 0.81%). Since many of the increased temperatures could not be explained by conventional means, it has to be assumed that the treatment itself caused the fever, possibly activating the monocyte hormone interleukin 1. It is of further note that there was no difference in the magnitude of the temperature due to septicaemia or to no obvious cause. This finding necessitates in our opinion an early antibiotic therapy in those cases where fever develops without clear explanation.

HTLV-III antibodies in hemodialysis patients--a consequence of blood transfusions?

An investigation for HTLV-III antibodies in chronic hemodialysis patients revealed in four out of 276 patients a positive result using the ELISA and western blot techniques. All HTLV-III positive patients had received blood transfusions. As it has been shown that a needle stick could transmit the HTLV-III, it is suggested that hemodialysis patients who have received frequent blood transfusions should be screened.

Hypercalcemia and elevated serum 1,25-dihydroxyvitamin D3 in a patient with Hodgkin's lymphoma

A 74-year-old woman was hospitalized because of decreased appetite, fatigue, and weight loss. The laboratory examination revealed hypercalcemia, a slightly increased serum creatinine level, and a markedly elevated serum level of 1,25-dihydroxyvitamin D3. The most important finding the physical examination revealed was enlarged inguinal lymph nodes. A biopsy disclosed lymphocyte-depleted Hodgkin's disease. After steroids, but not after calcitonin, both the elevated calcitriol concentration and serum calcium normalized. In spite of intensive chemotherapy, a further episode with hypercalcemia occurred and increased 1,25-dihydroxyvitamin D3 serum levels were observed. According to the available evidence it seems probable that the humoral hypercalcemia in this patient resulted from production of 1,25-dihydroxyvitamin D3 in the tumor.

Performance and biocompatibility of a new hemodialysis membrane

Performance studies and investigations of the biocompatibility of a new hemodialysis membrane were conducted in patients being chronically hemodialyzed. The investigated polycarbonate membrane revealed a very satisfying performance with regard to clearance values and the ultrafiltration rate. The biocompatibility studies showed a significant leukopenia and an increase of C5a, platelet factor 4 and granulocyte elastase. Thrombocytes and C3d remained unchanged. Long-term studies have to confirm whether or not the new membrane is more biocompatible, a suggestion which could be advanced, as no febrile episodes were observed during any treatment, a finding which is not typical for Cuprophan hemodialysis.

Effect of long-term administration of 1,25-dihydroxyvitamin D3 and 1 alpha-hydroxyvitamin D3 on the calcium content of the aorta, heart and kidney of normal and uremic rats

Studies in uremic rats were performed to see whether or not the long-term administration of therapeutical doses of 1,25-Dihydroxyvitamin D3 or 1 alpha-hydroxyvitamin D3 would induce histological changes in the aorta or increase the calcium content of the aorta or the heart. In contrast to observations of others, no effect of both vitamin D sterols could be observed on both investigated tissues. However, the remnant kidneys of the rats treated with both vitamin D compounds showed a significantly increased calcium content. According to these results one cannot exclude that the chronic application of active vitamin D metabolites has induced a calcium deposition in the remnant kidney. This finding deserves special attention, although we found, on the other hand, no evidence that an underlying arterial disease is aggravated by this therapy.

Effect of an acute protein load on the creatinine clearance in healthy vegetarians

In normal man an acute protein load increases the glomerular filtration rate (GFR) significantly, which seems to represent a renal functional reserve. Healthy vegetarians are known to have a statistically reduced baseline GFR. We performed three creatinine clearance studies (24-h study design) on each of nine healthy vegetarian subjects. The first clearance was measured as baseline, the second one was done on day 2 after an oral protein load of 100 g vegetarian protein (1.2-2.0 g/kg body wt.), respectively, ingested within half an hour. The third clearance, serving as a control, was done on day 14. All subjects had their normal vegetarian meals during the study. All vegetarians had at all times a normal serum creatinine level. The mean baseline creatinine clearance was 65.4 +/- 33.3 ml/min. 1.73 m2. In five of nine vegetarians we found a significant increase of the creatinine clearance after the protein load of 66.0% (mean) and a decrease to the baseline values, respectively, when the control clearance was measured. The remaining four vegetarians did not increase their creatinine clearance immediately after the protein challenge and their control clearances were found to be significantly reduced (-40.2%) compared to the individual baseline.

Endotoxin-induced acute renal failure in mice. Effects of indomethacin and the thromboxane-synthetase antagonist UK 38.485

Functional acute renal failure (ARF) was induced within 24 h following i.p. injection of 200 micrograms E. coli endotoxins (ET) into C3H/HeHan mice. Pre- and post-treatment with either UK 38.485, a selective thromboxane (TX)-synthetase inhibitor, or with the cyclo-oxigenase inhibitor, indomethacin (IM), does not prevent acute renal failure in these mice. Histologically, only very little fibrin degradation and few microthrombi are present 24 h later in the kidneys, so that disseminated intravascular coagulation (DIC) mechanisms cannot have caused the significant azotemia. Slight histological changes are accentuated in the UK 38.485-treated group. Only the indomethacin group has a significantly increased mortality as compared to all other groups. We conclude from our study that with low dosages of endotoxins functional ARF can be induced in mice without a circulatory shock and early mortality and that both UK 38.485 and IM are of little value in preventing it.

Parathyroid hormone and 1,25-dihydroxyvitamin D3 affect the tissue concentrations of zinc in uremic rats

The tissue concentration of zinc was studied in normal and uremic rats. Differences between the groups only reached significance when either parathyroid hormone or 1,25-dihydroxyvitamin D3 were administered. Uremic rats having obtained these compounds showed a significantly higher concentration of zinc in their liver, whereas their serum content of zinc was decreased.

Effect of diets containing varying concentrations of essential fatty acids and triglycerides on renal function in uremic rats and NZB/NZW F1 mice

Influences of essential fatty acids (EFA) and triglycerides as reasons for the progression of chronic renal failure are still in debate. We studied the outcome of four diets containing different concentrations of triglycerides and EFA in 5/6 nephrectomized rats and in NZB/W mice up to 45 weeks. The results showed no significant differences in the outcome of survival rate, proteinuria, urea, and creatinine levels as well as histological findings in the different groups of both animal models. We conclude that diets containing EFA up to C18:2 or being free of EFA or that triglyceride-enriched diets have no influence on the natural course of the renal disease in these both experimental models.

[Analysis of antibiotic therapy in 500-bed hospital: indications, administration and possibilities of cost reduction]

The introduction of a justification form in a 500-bed acute hospital before starting therapy with antibiotics resulted in a more than 30% decrease of current antibiotics costs. The cost reduction was mainly caused by reduced consumption of very expensive antibiotics. Moreover, analysis of the justification form revealed that more than 20% of diseases such as pneumonia, bronchitis, postsurgical complications, or skin and bone infections were diagnosed and treated without sufficient clinical and bacteriological documentation. The use of a justification form for antibiotics is therefore not only useful for cutting costs, but also for educating physicians in how to administer rational prophylaxis and therapy with antibiotics.

Failure to show a temperature-dependent vascular stability during hemofiltration

The effect of different blood temperatures on the vascular stability during hemofiltration was evaluated in 10 patients being in the regular chronic hemofiltration program. In contrast to recent data, no differences could be observed with regard to the heart rate, systolic blood pressure or mean arterial pressure, when the blood returned to the patient either with a temperature of 34.68 degrees C or 36.22 degrees C. According to these data it is therefore presently not justified to consider differences in the blood temperature as a critical determinant for the vascular stability during HF.

Successful hemodialysis for acute renal failure in late pregnancy

The occurrence of an acute renal failure during pregnancy does not necessarily imply the termination of the gestation. A 21-year-old pregnant woman was successfully dialyzed because of an acute azotemia developing in the 27th week of pregnancy. After repeated hemodialysis treatments the renal function recovered and the patient gave birth to a healthy child at full term. It is suggested that hemodialysis should be performed as often as possible (twice daily) in order to avoid any dramatic changes of the serum chemistry and the fluid content of the body. Furthermore, such a regimen allows the regular intake of calories, which is considered as especially important in such an event.

[Vitamin D 1980--a stocktaking (author's transl)]

Vitamin D3 and its various metabolites have a central position in the regulation of the calcium- and phosphorus metabolism. Of special importance is 1,25-dihydroxyvitamin D3, which is almost exclusively synthesized in the kidney. Its production is dependent upon several hormonal stimuli and of course occurs normally only in intact renal tissue. The multifactorial regulation of its formation implies that a variety of diseases could cause disturbances in the metabolism of vitamin D. 1,25-dihydroxyvitamin D3 exerts its biological effects not only at the intestine, bone and kidney, but as well presumably in organs as the parathyroid glands, hypophysis, pancreas and skin. 24,25-dihydroxyvitamin D3--although its biological value is still in debate--represents possibly a second vitamin D-hormone of importance. Inspite of intensive research work the metabolic fate of vitamin D3 and its full biological significance is not yet entirely understood.

Digoxin-quinidine interaction in patients with renal failure

Investigations were performed in order to study whether or not quinidine would exert similar effects on the serum digoxin concentration in patients with renal failure as in normal subjects. Fourteen out of fifteen patients showed a significant increase of the serum digoxin level after four days of quinidine application. This indicates, that the quinidine effect is not solely caused by a decrease of the renal digoxin clearance, although nine patients, not being hemodialysed, revealed a correlation between their creatinine clearance and the rise of the serum digoxin concentration after quinidine. As however, the patients on hemodialysis did not show higher digoxin levels than those treated conservatively, it is suggested that the degree of the uremic intoxication might be responsible for the observed correlation.

Failure to show a correlation between serum parathyroid hormone, nerve conduction velocity and serum lipids in hemodialysis patients

The proposed role of parathyroid hormone as an important agent for the development of certain uremic complications could not be confirmed in studies correlating, in dialysis patients, the nerve conduction velocity and the serum lipids with four different immunochemically defined forms of circulating parathyroid hormone. To a certain extent the data invalidate suggestions which favor parathyroid hormone as a leading uremic toxin.

[Treatment of renal osteopathy with 5,6-trans-25-hydroxycholecalciferol (author's transl)]

The influence of 5,6-trans-25-hydroxycholecalciferol on renal osteopathy was investigated in a total of 132 patients in 26 dialysis centres. Various doses were used, the average being 4000-6000 IU/day. In 32 patients a daily dose of 6000-9000 IU was used. The average individual duration of treatment was 276 days with a maximum of 910 days. Histologically there was an improvement in the renal osteopathy in 55.9% of evaluable cases (n = 34) and in 25.3% there was no deterioration. Radiographically these results were found in 21% and in 70.5% of evaluable cases (n = 105). Serum calcium increased in 46.6% of cases (n = 131), remained the same in 32.8% and decreased in 20.6%. The changes in alkaline phosphatase were similar : it dropped in 42.1% of patients, remained the same in 28.1% and rose in 29.8%. Immunoreactive parathormone which was invariably raised at the beginning of treatment (n = 36), fell in 25.0%, remained the same in 44.4% and rose further in 30.6%. The clinical symptoms of renal osteopathy which had been present in 57 patients improved in 51.0%, remained the same in 46.0% and deteriorated in 3.0%. Signs of intolerance and side effects were rare. Severe hypercalcaemia did not occur.

Chronic hemofiltration. A critical evaluation of a new method for the treatment of blood

The experiences which have been compiled in more than 2400 hemofiltrations confirm that this method represents an alternative way of treating uremic patients. The main advantages of chronic hemofiltration are the comfort of the patient and the ease in handling excess overhydration without extending treatment time, which is less than 3 X 3 hours/week if adequate hemofilters are used. With regard to the improvement of such typical uremic complications as severe hypertension, hypertriglyceridemia or neuropathy, hemofiltration does not seem to be superior to hemodialysis. However, since most hemofiltration patients do not require phosphate binders and, additionally, remarkable amounts of parathyroid hormone are removed during one hemofiltration, it appears possible that hemofiltration might be an important therapeutic alternative for those renal patients who suffer from severe hyperphosphatemia and secondary hyperparathyroidism.

[Investigations on the pharmacokinetics of pentoxifylline in chronic renal failure (authors transl)]

The pharmacokinetical behaviour of 14C-labelled pentoxifylline was investigated in normal volunteers and in patients with different stages of impaired renal function. It was shown that in patients, having a creatinine-clearance of less than 10,0 ml/min., occurs an accumulation of pentoxifylline. This finding leads to the conclusion that in patients with advanced renal failure the daily dose of pentoxifylline should be adjusted to the diminished renal elimination.

The hemofiltration system: variations of the negative pressure

The physical conditions of the hemofiltration process are briefly discussed to describe the applied system that is characterized by a negative pressure pump which is directly attached behing the filter. A schema is presented that shows the characteristics of a fully automatic hemofiltration apparatus that is presently in development.

Parathyroid hormone-, 25-OH-vitamin D-, and digoxin levels in patients treated by chronic hemofiltration

Immunoreactive parathyroid hormone (iPTH) was measured in the serum and filtrate before, during and after hemofiltration. iPTH regularly declines during hemofiltration; one patient, investigated for a longer period, showed a normalization of iPTH serum level with this treatment. The iPTH values found in the hemofiltrate were remarkably high, a finding that could be explained by non-specific effects, by the occurrence of hormone fragments or by an increased secretion rate. At any rate, the results suggest a filtration of parathyroid hormone and/or hormone fragments. On the other hand, it was impossible to detect any 25-OH-vitamin D in the hemofiltrate. Finally, digoxin could be found in the filtrate, but only in very low concentrations.

Clinical aspects of hemofiltration

We report on clinical experiences obtained in 7 uremic patients treated since January 1976 3 times weekly by chronic hemofiltration. The observations which we collected in more than 300 treatments suggest that hemofiltration might be superior to conventional hemodialysis. The main advantages of this treatment are characterized by its better control of hypertension, hyperhydration, and possibly of uremic bone disease. Furthermore, the applied acrylonitrile membrane allows the removal of substances with a molecular weight up to 60,000, similar to the glomerular basement membrane. Additionally, we report on methodological problems, on the compatibility of hemofiltration, and finally on its efficiency for removal of different uremic solutes.

[Immunoreactive parathyroid hormone, 25-hydroxycalciferol and bone histology in renal osteodystrophy (author's transl)]

Immunoreactive parathyroid hormone (iPTH) and 25-hydroxycalciferol (25(OH)D) serum levels were determined in 32 patients with renal osteopathy, they were correlated with the results of bone biopsy and other clinical parameters. iPTH was closely related to bone histology, it did not correspond to serum calcium and alkaline phosphatase, but the correlation to serum phosphate was statistically significant. 25(OH)D levels were not related to the histological findings of osteomalacia or increased bone resorption, while a correlation between the vitamin D metabolite and serum calcium could be observed. Since iPTH and 25(OH)D levels exhibited a significant correlation, an inhibitory effect of 25(OH)D on parathyroid gland function in renal failure was discussed.

[Effect of pentoxyfylline on the organ distribution of 47Ca and on intestinal Ca absorption and secretion in the rat (author's transl)]

The influence of 3,7-dimethyl-1-(5-oxo-hexyl)-xanthine (pentoxyfylline, Trental) on organ distribution of 47Ca and on intestinal Ca absorption and secretion was studied in rats. Oral application of 4 mg/kg bodyweight pentoxifylline was followed after 30 min by a significantly higher accumulation of orally applied 47Ca in the intestinal wall as compared to untreated controls, while in other organs the 47Ca activity was lower than in control animals. When 47Ca was given i.p. and pentoxifylline at the same dose was applied orally 24 h later, there was no difference in organ distribution of 47Ca between treated rats and untreated controls after 30 min. There was likewise no difference in serum Ca concentration. On the other hand, i.v. infusion of 20.8 mg/kg bodyweight pentoxifylline was followed by a significant fall of serum Ca. At the same time, there was a significant reduction of intestinal Ca net absorption, as demonstrated by the intestinal perfusion technique, while Ca net secretion was not influenced. The possible mechanisms causing the pentoxifylline induced reduction of serum Ca concentration are discussed.

Pharmacokinetics of 5,6-trans-25-hydroxycholecalciferol, a synthetic analogue of vitamin D3, in man

Vitamin D analogues of high biological activity are probably useful in the treatment of renal osteodystrophy. The pharmacokinetics of the synthetic compound 5,6-trans-25-hydroxycholecalciferol have been studied in healthy subjects who were of normal vitamin D status. In comparison to natural 25-hydroxy-cholecalciferol, serum levels of the analogue were lower and its half-life in blood after oral or intravenous administration was considerably shorter. In normal subjects no increase of dihydroxylated metabolites in serum was observed within seven days of an intravenous dose.

The effect of Solanum malacoxylon on rachitic bone lesions in the rat

The plant Solanum malacoxylon (S.M.) is known to cause severe soft tissue calcifications in cattle and sheep and has recently become of special interest since it exerts biological actions which resemble those of vitamin D. In order to investigate whether S.M. is capable to improve the rachitic bone changes in vitamin D and phosphate deficient rats, a watery extract of 50, 100 and 200 mg S.M. was fed daily to these animals over a period of 10 days. The width of epiphyseal plates was compared after the time with those of rats treates with 0, 0.225, 0.45, and 0.9 IU of vitamin D3 daily. There was a dose related curative effect of S.M. on the epiphyseal lesions very similar to that of vitamin D3. The hypercalcemic and hyperphosphatemic effect of S.M. was identical to that of vitamin D3. The 25-hydroxy-vitamin D serum levels remained almost undetectable in the S.M. treated rats as well as in the vitamin D3 treated animals.

The metabolism and organ distribution of 5,6-trans-25-hydroxycholecalciferol, an analog of vitamin D-3 in vitamin D-deficient rats

Investigations have been performed on the metabolism and organ distribution of 5,6-trans-25(OD)D-3, which represents an analog of vitamin D-3 being active in uremia. This analog is rapidly metabolized into at least two more metabolites. The main storage organ for this compound seems to be fat, whereas liver and intestinal mucosa showed at 24 hrs the highest concentration of polar metabolites. In contrast to 25(OH)D-3 5,6-trans-25(OH)D-3 is much less absorbed from the intestinal tract, which should be considered if this compound is applied for treatment of uremic bone diseases.