Effect of haemodialysis after contrast medium administration in patients with renal insufficiency.

BACKGROUND: The study was designed to investigate the influence of haemodialysis on the pharmacokinetics of the non-ionic contrast medium iopentol and the outcome of radiocontrast nephropathy in patients at risk undergoing angiography. METHODS: We prospectively studied 30 patients with reduced renal function (mean serum creatinine concentration (+/- SEM), 2.4 +/- 0.16 mg/dl (212 +/- 14 mumol/l)). Patients were randomly assigned to receive either a haemodialysis procedure for 3 h, started as soon as possible (63 +/- 6 min) after administration of contrast medium, or a conservative treatment. Serum concentrations of iopentol and creatinine were followed for up to 14 days. RESULTS: The extracorporal plasma clearance of contrast medium was 71 +/- 2.5 ml/min. The fraction of the dose eliminated was 32 +/- 3%. The rate of radiocontrast nephropathy (defined as serum creatinine increase of > or = 0.5 mg/dl (44 mumol/l) within 48 h) after administration of contrast medium was similar in both groups (53 and 40% in group 1 (haemodialysis) and group 2 (conservative treatment) respectively). The course of absolute changes in serum creatinine over the whole observation period was not different in both groups. CONCLUSIONS: The data indicate that haemodialysis eliminates contrast medium effectively, but it may not influence the incidence or outcome of contrast induced nephropathy.

[Unilateral diffuse pulmonary involvement in vasculitis with anti-neutrophil cytoplasmic antibodies and anti-glomerular basement membrane antibodies]. / Einseitige diffuse Lungenbeteiligung bei Vaskulitis mit Anti-Neutrophilen-Zytoplasma-Antikörpern sowie Antikörpern gegen glomeruläre Basalmembranen.

A previously healthy 51-year-old man, hospitalized because of fatigue and joint complaints, was found to have left-sided diffuse pulmonary infiltration and a rapid rise in creatinine concentration. Anti-neutrophil cytoplasmic antibodies (cANCA) and anti-glomerular basement antibodies (anti-GBM) were found in serum. Renal biopsy revealed extracapillary glomerulonephritis with diffuse half-moon formations. Immunohistology showed a diffuse granular pattern for immunoglobulin G, M and complement C3, without linear deposits. Immunosuppressive treatment combined with plasmapheresis brought about rapid clinical improvement and normalization of the lung involvement and renal function, as well as a fall in the cANCA titre. During a follow-up period of 5 years there has been no recurrence of symptoms, although the anti-GBM titre remained strongly positive and the cANCA titre twice rose to abnormal levels.

Induction of experimental allergic arthritis with outer surface proteins of Borrelia burgdorferi.

OBJECTIVE: The arthritogenic potential of the cationic outer surface proteins (Osp) from Borrelia burgdorferi was tested in rats. METHODS: Water-soluble Osps were prepared by butanol extraction and were administered by intraarticular injection. Tissue injury was assessed by scintigraphy and histology. RESULTS: A mild arthritis was seen in naive rats. Preimmunized animals had more severe, longer lasting bouts of inflammation. CONCLUSION: The Osps of Borrelia burgdorferi are potent arthritogens in rats. These immunodominant antigens may play a role in the development of Lyme arthritis in humans.

[Color-coded duplex sonography in the diagnosis of renal venous thromboses in the early phase following kidney transplantation]. / Farbkodierte Duplexsonographie zur Diagnostik von Nierenvenenthrombosen in der Frühphase nach Nierentransplantation.

A total of 91 colour-coded duplex Doppler ultrasound scans were performed in the early phase following renal transplantation in 53 out of 109 patients (48.6%) between 1. 1. 1992 and 15. 3. 1993. The indications for the investigation were primary failure of functional improvement in the transplanted kidney or secondary worsening of function. In five of the 53 patients (ten scans) constant retrograde flow in the segmentary arteries provided specific evidence of renal vein thrombosis, this diagnosis being confirmed histologically following nephrectomy. The Pourcelot index was raised (RI > 0.72) in all five cases. The RI was also raised in 35 of 53 patients; however, continuous retrograde diastolic flow was absent. The results of renal biopsy and the clinical course both excluded renal vein thrombosis in these cases. The colour Doppler ultrasound scans were unremarkable in 13 patients. The comparison group consisted of 151 patients in the later posttransplantation phase (> 2 months), in whom 171 colour Doppler ultrasound scans showed no signals associated with renal vein thrombosis. In agreement with the literature, these results show that colour-coded duplex Doppler ultrasound should be regarded as the definitive diagnostic procedure for renal vein thrombosis after transplantation, and if positive findings are obtained further invasive diagnostic procedures can be avoided.

Cationic Yersinia antigen-induced chronic allergic arthritis in rats. A model for reactive arthritis in humans.

Cationic antigens are known to have considerable arthritogenic potential in experimental systems. During a systematic search for suitable, naturally occurring candidates an intracellular protein was isolated from the ribosomal pellet of Yersinia enterocolitica 0:3, a bacterial strain associated with reactive arthritis in humans. The protein is highly cationic, contains two 19-kD polypeptide chains linked by a disulfide bond, and reveals a strong tendency for spontaneous aggregation. It is suggested to be a nucleic acid binding protein. We tested this antigen for its ability to induce arthritis after intra-articular challenge in preimmunized rats. An acute inflammatory phase followed by transition to chronicity was observed both by technetium-99m scintigraphy and from histology. Massive polymorphonuclear leucocyte infiltration of the synovium was seen early on and fibrosis and thickening of the joint capsule occurred in later stages. Control groups showed no evidence of inflammation. Western blot and ELISA analysis of unselected sera from Yersinia enterocolitica 0:3-infected patients revealed antibodies to the antigen in the majority of cases, whereas healthy individuals rarely reacted. This is the first report of a naturally occurring cationic antigen capable of inducing immunologic tissue injury; it justifies the speculation that cationic antigens from prokaryotic cells could trigger reactive arthritis in humans.

Handling of cationic antigens in the joint and induction of chronic allergic arthritis. In vivo studies in the rat.

The aims of the present study were to define, under in vivo conditions, factors governing antigen binding and persistence in the rat joint and to establish a chronic arthritis model by means of a natural polycation. The influence of size as well as charge on antigen handling was examined using a range of chemically cationized proteins and natural polycations. Arthritis was induced by intraarticular challenge in preimmunized rats. Immunofluorescence studies revealed that not only pI, which must exceed pH 8-9, but also molecular size was a decisive parameter: only antigens of more than 40 kD were able to persist for significant periods in joint structures. All existing models of antigen induced chronic arthritis in rodents utilize chemically cationized proteins. We extended this system to natural polycations by showing that lysozyme (pI 11.3; MW 14 kD) in tetrameric, charge conserved form (MW 56 kD) as a model-antigen was able to induce chronic arthritis in the rat. After intraarticular challenge of preimmunized animals the course of inflammation was assessed both by 99mTechnetium-pertechnetate (99mTc) scintigram and from the histology. In contrast to monomeric lysozyme, which evoked only a transient inflammatory response (less than two weeks), tetrameric lysozyme induced a chronic arthritis, which still persisted at day 90. Our results show that the ability of cationic antigens to trigger chronic arthritis is vitally size dependent. This is also the first report of a natural polycation acting as an arthritogen, thus providing an experimental basis justifying the search for cationic microbial antigens in human post infectious reactive arthritis.

Isolation of an outer membrane protein complex from Borrelia burgdorferi by n-butanol extraction and high-performance ion-exchange chromatography.

Borrelia burgdorferi, the causative agent of Lyme disease, expresses two major membrane proteins, designated outer surface proteins A and B, which are of antigenic relevance, especially in the chronic phase of Lyme disease. Both proteins exhibit strain-related molecular weight variation. A method is described for obtaining these proteins from the bacterial membrane, without the use of detergents, by a combination of n-butanol extraction and cation-exchange chromatography on a Mono S fast protein liquid chromatographic column. This method yields up to five times larger amounts of the proteins in aqueous solution than previously described protocols, which applied ionic or non-ionic detergents. A comparison of extracts obtained by this method from different Borrelia burgdorferi strains is reported.

Incidence and prognostic importance of silent ischaemia after PTCA: a prospective study.

To evaluate the influence of PTCA on symptomatic and asymptomatic ischaemic episodes in 94 patients, 24-h ambulatory, electrocardiographic Holter recordings were obtained before and after successful PTCA. Sixty-four per cent of patients had one-vessel disease, 28% two-vessel disease and 8% had three-vessel disease. Ischaemic episodes were present in 36% of patients before PTCA, of which 71% were silent; after PTCA, 23% of patients had ischaemic episodes, of which 98% were silent; thus silent ischaemic episodes were improved by PTCA to a lesser degree than symptomatic ischaemic episodes. Successful PTCA lead to a significant reduction in total number and duration of ischaemic episodes but not to a complete abolition. Patients with silent ischaemic episodes after PTCA had also a higher incidence of silent ischaemic episodes before PTCA. Functional and haemodynamic improvement was comparable in patients with and without silent ischaemic episodes. No specific cause for the persistent or newly appearing silent ischaemic episodes after PTCA could be identified; they are not indicative of an inadequate dilatation and cannot be considered as a risk factor for early restenosis. A possible explanation could be a traumatically induced, increased vascular tone in susceptible patients.