Biocompatibility of a cuprophane charcoal-based detoxification device in cirrhotic patients with hepatic encephalopathy.

Extracorporeal detoxification has been proposed to treat patients with hepatic encephalopathy (HE) not responding to standard therapy. To investigate the biocompatibility of a cuprophane charcoal-based detoxification device, a prospective, randomized, controlled study was performed. Of 41 consecutive patients with cirrhosis and HE grade II or III who did not improve with conventional treatment, 20 patients (median age, 56 years; range, 33 to 71 years; 13 men) were randomly assigned to either ongoing conventional treatment or one additional 6-hour treatment with a sorbent suspension dialysis system. Main outcome parameters were physiological function and blood parameters of biocompatibility. In the 10 patients undergoing combined conventional and sorbent suspension dialysis treatment, blood pressure remained unchanged and body temperature and heart rate increased (P: < 0.01). Platelet count decreased (medians, from 75 to 26 g/L; P: < 0.001) and international normalized ratio increased after combined treatment (2.0 to 2.2; P: < 0.001). Three patients developed bleeding complications during treatment or shortly after. Treated patients showed increases in levels of plasma elastase (104 to 586 microg/L; P: = 0.001), tumor necrosis factor-alpha (5.4 to 7.5 pg/mL; P: = 0.04), and interleukin-6 (118 to 139 pg/mL; P: = 0.04), but not interferon-gamma and E-selectin. No changes were observed in the 10 patients treated conventionally. In conclusion, despite technical refinements compared with charcoal hemoperfusion, biocompatibility of sorbent suspension dialysis is still very limited. Clinical complications were apparently caused by blood-membrane interactions and disseminated intravascular coagulation. We suggest further developments in design and appropriate strategies of anticoagulation to improve the biocompatibility of artificial liver support.

Quantification of leukocyte migration: improvement of a method.

Eighteen different permeable membrane supports with and without confluent endothelial cell monolayers were incubated with normal donor derived neutrophils in the upper chambers of a 24 multiwell double chamber system. In order to study transmembrane or transendothelial leukocyte migration leukocytes were stimulated by chemoattractants, or endothelial cells were activated by IL-1. After coincubation the membrane supports building the upper chambers were discarded. Using this technique, leukocytes that had migrated into the lower chamber were exposed to the fluorescent dye calcein AM without additional washing or transfer steps. Absolute cell counts were determined computer assisted using dilution series of calcein AM labeled leukocytes as standards. Serial dilutions of neutrophils exposed to calcein AM showed reproducible linear fluorescence intensity, and relative fluorescence intensity correlated significant with cell counts (r2 = 0.974, p < 0.0001). Out of 18 membrane supports only one was suitable for our assay set up. Best technical and optical performance was achieved with a membrane made of polyethylene terephtalate with a pore size of 3 mm at a pore density of 0.8 x 10(6)/cm2. Stimulation of leukocytes or endothelium by FMLP or IL-1 revealed an increase of transendothelial migration to 7.2 +/- 1.8 x 10(5) PMN and 5.1 +/- 0.7 x 10(5) PMN respectively if compared with medium (0.6 +/- 0.2 x 10(5) PMN). IL-1 induced migration of neutrophils was inhibited by anti IL-1 autoantibodies derived from chronic renal failure patients (IL-1: 100% of PMN migrated, anti IL-1 antibody: 39% of PMN migrated, control antibody: 84% of PMN migrated). In summary, a simple fluorimetric assay was established for the quantification of transmembrane and transendothelial leukocyte migration.

Disturbed latex immunoassays for C-reactive protein and ferritin in a renal transplant patient due to polyclonal IgM hypergammaglobulinaemia.

BACKGROUND: C-reactive protein (CRP) and ferritin serum levels represent routine laboratory parameters in the monitoring of renal failure patients. Analysis of CRP, ferritin and other serum proteins can be performed using latex-enhanced or non-latex-enhanced immunoassays. We report on a renal transplant patient with polyclonal IgM hypergammaglobulinaemia having markedly elevated serum CRP and ferritin levels (as detected by latex-enhanced immunoassays) in the absence of clinical signs of an infectious or malignant disorder. METHODS: CRP and ferritin serum levels were determined with various immunoassays with and without latex enhancement. To characterize the causative agent for the elevated CRP and ferritin values, the patient's and a control serum were fractionated by gel filtration on a Sephacryl S-300 column. Serum fractions were subjected to further analysis for reactivity in CRP and ferritin assays. In addition, patient's serum samples were investigated for reactivity with various other latex-based immunoassays (rheumatoid factor, antistreptolysin O, antistreptococcal DNase B). RESULTS: Using latex-enhanced CRP and ferritin immunoassays, markedly elevated serum levels were obtained (CRP 726 mg/l determined by turbidimetry, 398 mg/l determined by nephelometry; ferritin, 20,000 micrograms/l determined by turbidimetry). In contrast, assays without latex enhancement revealed levels within the normal range for both serum proteins (CRP < 5 mg/l, ferritin 52 micrograms/l). The analysis of the patient's serum by gel filtration revealed an interference of the patient's IgM with latex particles used in the CRP and ferritin assays. CONCLUSION: Our study demonstrates that even polyclonal IgM hypergammaglobulinaemia can disturb a large array of latex-enhanced immunoassays used for routine diagnostic procedures. This is of particular interest for the management of allograft recipients in whom monoclonal and polyclonal gammaglobulinaemia are frequently observed. We therefore recommend reanalysis of the respective plasma proteins by latex-free assays in patients with hypergammaglobinaemia showing no clinical signs of an acute infectious disease or malignant disorder.

Supraclavicular approach to the subclavian/innominate vein for large-bore central venous catheters.

Infraclavicular and internal jugular catheterization are commonly used techniques for hemodialysis access, but may at times be impeded in patients whose anatomy makes cannulation difficult. In an effort to enlarge the spectrum of alternative access sites, we evaluated the supraclavicular approach for large-bore catheters. During an 18-month period we prospectively collected data on success rate and major and minor complications of the supraclavicular access for conventional dialysis catheters as well as Dacron-cuffed tunneled devices in 175 adult patients admitted for various extracorporeal therapies and bone marrow transplantation. Two hundred eight large-bore catheters (99 conventional dialysis catheters, 63 semirigid tunneled Dacron-cuffed catheters, and 46 Hickman catheters) were successfully placed in 164 patients (success rate, 93.8%), 58 (33.1%) of whom had been previously catheterized. Complications included pneumothorax (one patient), arterial puncture (seven patients), and puncture of the thoracic duct (two patients) without sequelae. Postinsertional chest radiographs demonstrated impressive coaxial lie of most catheters. Catheter malpositions occurred only sporadically (1%). Difficulty of introducing the catheter via a placed sheath was rarely observed. There was no clinically significant evidence of catheter-induced venous thrombosis or stenosis. We conclude that the supraclavicular route is an easy and safe first approach for large-bore catheters, as well as a useful alternative to traditional puncture sites for precatheterized and anatomically problematic patients.