Clinical and metabolic aspects of continuous ambulatory peritoneal dialysis (CAPD)

Experience with CAPD in 14 patients, treated for periods of 2–10 months, is presented. Clinical and biochemical control of uremia appeared adequate in all patients except one. Control of extracellular volume and hypertension was easier with CAPD than with intermittent peritoneal dialysis (IPD). Nine episodes of peritonitis occurred in 5 patients (one peritonitis/8 patients months). Mean protein loss was 9.7 ± 2.7 g per day. In 6 patients on IPD oral glucose tolerance test resulted in a paradoxical rise of HGH, whereas this was not observed after 4 months of CAPD.

Side Effects of Hybrid Liver Support Therapy: TNF-α Liberation in Pigs, Associated with Extracorporeal Bioreactors

During acute liver failure, hybrid liver support therapy could serve as a bridge to liver transplantation. In this desired temporary use, immune competent cell responses, such as the production of cytokines, might be of limiting relevance. We have investigated the Tumor Necrosis Factor-α (TNF) liberation in two models using pigs, connected with an extracorporeal bioreactor with homologous hepatocytes: TNF liberation was measured in arterial plasma during a 4 day perfusion time in untreated animals, model (i), and during short term perfusion of hepatectomized pigs in model (ii). Animals four days after catheter implantation in model (i) had TNF values of < 5 pg/ml. After connecting the system without hepatocytes, TNF rose to 9.7 ± 2 within 120 min and rose further to 32.6 ± 6 pg/ml within 4 hours after filling the system with the homologous hepatocytes. After 24 hours of continuous perfusion and during four days of perfusion, the TNF levels were lowered to baseline levels. In model (ii), TNF rose to 220 ± 130 pg/ml within 180 min and decreased to 110 ± 10 pg/ml within six hours, whereas controls without hepatocytes showed mean levels with a maximum of 120 ± 20 pg/ml. In both models, there was no correlation between TNF levels and clinical abnormalities such as fever or shock symptoms. There is evidence for an activation of blood cells during experimental extracorporeal hybrid support. No typical side effects were, however, observed. Thus, TNF mediated extracorporeal cell activation does not appear to limit the application of homologous hybrid liver support therapy.

Variables Associated with the Assessment of Systemic Tumor Necrosis Factor Alpha Levels during Hemodialysis

Conflicting results have been published concerning the systemic induction of the cytokine tumor necrosis factor alpha (TNFα) during hemodialysis (HD). We therefore evaluated in vitro TNFα production in whole blood as well as in vivo variability of TNFα levels in patients on long-term HD. Whole blood was incubated at room temperature (RT) with or without exogenously added endotoxin (ET), and plasma-TNFα was measured after 5, 30, 120, 240, and 960 min by specific enzyme immunoassay. Additionally, plasma-TNFα before and after 120 and 240 min HD was studied longitudinally once a week over a period of 4 weeks in 36 patients on Cuprophan® (CU, n=23) or polysulfone-F60 (PSu, n=13) HD. Mean plasma TNFα levels in vitro rose from (mean) 8 pg/ml after 5 min to 12 pg/ml (120′) and 32 pg/ml (960′) even without ET addition, and to 18 pg/ml (after 120′) and 88 pg/ml (after 960′) when 0.1 μg/ml ET were added. Pre-dialytic as well as intradialytic TNFα levels in patients showed high intra-individual variability. A substantial (> 100%) increase in plasma TNFα was observed during only 14 out of 84 treatments with CU and 20 out of 47 with PSu, however, the increase in TNFα was not statistically significant in either group. We conclude that the sampling procedure, if not carefully standardized, is a potential source of artifacts with regard to “systemic” TNFα levels. The high intra and inter-individual variability of plasma TNFα suggests that results of cross-sectional studies are questionable.

Leukotriene Release from Neutrophils of Patients on Hemodialysis with Cellulose Membranes

The role of cytokines in patients with chronic renal failure is currently under investigation. We therefore studied the release of leukotriene B4 (LTB4) from polymorphonuclear leukocytes (PMN) in stable dialysis patients treated with two different cellulose membranes, Cuprophan and Hemophan®, a modified cellulose with less complement activation. Six patients were treated for four weeks with Cuprophan then switched to Hemophan® for another four weeks. Before and after the last treatment of each period, PMN were separated from 20 ml heparinized blood by FICOLL density gradient centrifugation. Portions of 5x106 PMN were resuspended in Hanks' buffer and stimulated for 5 minutes with calcium ionophore A23187 (5 /μg/ml). LTB4 in cell supernatants was determined by specific radioimmunoassay. PMN from dialysis patients before HD released significantly (p<0.01) more LTB4 than healthy donors. No significant difference between pre- and post-dialysis values was observed with Cuprophan or Hemophan® dialyzers. Our data suggest that the acute effects of blood membrane interaction with either complement activating or non-activating dialyzers do not lead to changes in post-dialysis leukotriene metabolism, but leukotriene production is enhanced chronically in dialysis patients.

[Initial experiences with combined balloon angioplasty and rtPA thrombolysis in dialysis shunt failure]

The 23 interventions performed by us on 18 patients had a very high success rate both in intraarterial lysis therapy of obstructed haemodialysis shunts and in balloon angioplasty (19/23). Shunt failure had to be primarily treated by surgery in 3 cases only. The complications were confined to a rupture of a vessel that required surgical care. 14 shunts were found to be patent in a total of 18 patients (18 being of course as small patient group). Our experience leads us to believe that patients suffering from shunt insufficiency should always be primarily treated endoluminally if angiography confirms that intervention is possible. Surgical intervention is always advisable even if the result may occasionally be negative in a few rare cases.

A new method to evaluate the CAPD-catheter-exit and other percutaneous devices

A method that has proved to be the most sensitive approach for the early diagnosis of infection of the oral mucosa around dental implants has been used to monitor the exit-sites of percutaneous devices. For three months the state of the skin-catheter interface of 13 CAPD-patients was examined every four weeks. This examination included the measurement of pocket depth with the aid of a periodontal probe, the measurement of SFFR (sulcus-fluid-flow-rate) using standardized filter paper strips and a bacteriological swab of the exit-site. The results obtained demonstrated that SFFR can be measured around percutaneous implants. The measurement of SFFR appeared to be more useful in the monitoring of exit-sites of percutaneous devices than the measurement of pocket depth or the use of bacteriological swabs. Further studies for prolonged periods are necessary to determine whether measurement of SFFR can reliably predict onset of exit-site infection before clinical signs become evident.

[99mTc-MAG3 and 131I-OIH in patients with kidney insufficiency and with normal kidneys]

Renal clearance of 99mTc-mercaptoacetyltriglycine (MAG3) and 131J-orthoidohippurate (OIH) were compared by simultaneous measurement in 50 patients. Renal time-activity-curves of both radiopharmaceuticals were compared in 50 patients. With regard to the clearance, good correlation (r = 0.95) with a mean ratio MAG3-/OIH-clearance of 0.62 was found. No significant difference between patients with normal (n = 30) and impaired (n = 20) renal function could be demonstrated. Renal time activity curves and relative renal function showed good correspondence in patients with normal (n = 13) and impaired (n = 7) renal function. It is concluded that MAG3 may be used as substitute for OIH in patients with normal and impaired renal function.

Failure to detect naturally occurring serum inhibitors of hepatitis B virus deoxyribonucleic acid polymerase

Sera of patients with past or ongoing hepatitis -B virus infection were tested for the presence of inhibitors of hepatitis -B virus-specific deoxyribonucleic acid (DNA) polymerase activity. None of the sera tested, which included those from anti-hepatitis B surface- and anti-hepatitis B core antigen-positive hemophiliacs, anti-hepatitis Bc antigen-positive hepatitis B surface antigen carriers, patients with hepatitis B surface antigen-positive chronic active hepatitis, hepatitis B surface antigen-positive hemodialysis patients, tumor patients with minimal hepatitis, patients with acute type B, type A, and type non-A, non-B hepatitis and individuals with autoimmune phenomena, contained inhibitors of DNA polymerase activity. This implies that the DNA polymerase test is not affected when utilized to quantitate DNA-containing Dane particles. In addition, there is no evidence that inhibitors of DNA polymerase activity play some pathogenic role in the course of hepatitis B virus infection.

[Radioimmunological determination of HBeAg/anti-HBe in HBsAg-positive liver diseases and in "healthy" HBsAg carriers]

This paper describes a "solid-phase"-radioimmunoassay for the demonstration of HBeAg and anti-HBe. The investigations revealed the following results: 1. HBeAg is positive in all patients with acute type B-hepatitis during the acute phase of illness. During the normal course of the disease HBeAg turns to negative followed by an anti-HBe lasting for several months. 2. Cases with a persistent virus B-replication as HBsAg-positive CPH, CAH or patients on hemodialysis are positive for HBeAg in their serum. By means of the fluorescent antibody technique these patients have demonstrable HBcAg and HBeAg in their liver biopsies. 3. Healthy HBsAg carriers are anti-HBe-positive in their serum. In their liver biopsies there are no signs of an on-going virus B-replication (HBsAg and HBeAg negative). 4. The radioimmunological determination of HBeAg and anti-HBe enables us to differentiate between the groups with HBsAg positive acute or chronic hepatitis and the group of healthy HBsAg-carriers.

[Quantitative computerized tomographic bone mineral analysis in patients treated by regular haemodialysis (author's transl)]

Quantitative bone measurement has been done on the forearms of 40 patients (aged 20 to 67 years) undergoing long-term haemodialysis treatment. It turned out that trabecular bone shows a more substantial change of the mineralization than does cortical bone. In comparison to an age-correlated undialysed normal range the mean trabecular bone density was found decreased up to 100 percent, whereas cortical bone with a mean demineralization of 10 percent did not appear to be affected by the renal osteodystrophic alterations to that degree. Finally the results show that throughout the course of dialysis treatment there was a trend toward distinct loss of bone mineral with time. No relationship could be demonstrated between the bone mineral values and various biochemical parameters. The estimation of osseous mineral content in both trabecular and cortical bone was done with the aid of an improved computer assisted tomographic method introduced by Rutherford and Pullan.

[Bone density measurements by computer tomography (author's transl)]

The suitability of the E.M.I. mark I computer scanner for carrying out bone densitometry has been tested, using the forearm. Within the region of interest there was an almost linear relationship between CT densities and the concentration of the bone equivalent substance K2HPO4. By means of a special computer programme, the spongiosa and cortex of both forearm bones could be analysed quantitatively. The reproducibility of the results (coefficient of variation 5%) was similar to that of other procedures in current use. The advantage of the method lies in the fact that it is possible to estimate the spongiosa and cortex separately. Investigations on patients with normal bones have shown that senile demineralisation affects the cortex most severely. On the other hand, in renal osteopathies of chronically dialysed patients, demineralisation in the forearm predominantly involves the spongiosa.

[Bone scintigraphy in renal osteopathy]

25 Patients with chronic renal disease are investigated. In 16 cases with conservative treatment the bone scintigram showed pathological uptake according to the creatinine level, mainly in the joints of iliosacrum, hip, knee and ankles. In three patients increased uptake in the skull was found. The bone uptake found by scintigraphy was highly pronounced in the patients treated by dialysis. The most frequently involved regions were the joints of iliosacrum and hip, facial cranium, skull, pelvis and metatarsus. The count-rate ratio of cranium to chest was significantly increased in 6 patients. The investigations 6 months later showed in 4 cases a further increase compared with the first values. Count-rates of the skull were found to be comparable to the highly increased uptake in Paget's disease. Bone scintigraphy is a suitable method to estimate semiquantitatively the bone turnover in renal disease.

Knochenszintigraphie bei der renalen Osteopathie

Es wurden 25 Patienten mit chronischen Nierenerkrankungen untersucht. Bei 16 Patienten, die konservativ behandelt wurden, fand sich im Knochen-szintigramm in Abhängigkeit von der Höhe des Krea-tininspiegels pathologische Umbauvorgänge, vorwiegend im Bereich der lliosakral-, Hüft-, Knie- und Sprunggelenke sowie im Mittelfuß. 3 Patienten zeigten einen erhöhten Umbau in der Schädelkalotte. Die szintigraphisch nachweisbaren Knochenumbauvorgänge waren bei den 9 Dialysepatienten besonders ausgeprägt. Am häufigsten betroffen waren: lliosakral- und Hüftgelenke, Gesichtsschädel, Schädelkalotte, Beckenkamm, Schulter- und Kniegelenke und Mittelfuß. Das Impulsratenverhältnis aus Schädel und Thorax war bei 6 Patienten signifikant erhöht. Die Kontrolluntersuchung nach ca. 6 Monaten zeigte bei 4 Patienten eine weitere Erhöhung des Ausgangswertes. Es wurden Umbauraten im Bereich des Schädels erreicht, wie sie sonst nur beim M. Paget zu sehen sind. Nach den vorliegenden Untersuchungen ist die Knochenszintigraphie eine geeignete Methode zur semiquantitativen Beurteilung der Knochenumbauvorgänge bei der renalen Osteopathie.