Individualized anticoagulation with dermatan sulphate for haemodialysis in chronic renal failure

Background: Dermatan sulphate (DS) is a selective thrombin inhibitor with antithrombotic properties and low bleeding potential. In preliminary studies it was reported to be effective for preventing clot formation in the haemodialysis circuit. Methods: Ten patients on maintenance haemodialysis for chronic renal failure underwent three consecutive investigation phases. In phase 1 (individual dose titration), repeated dialyses were preformed with increasing doses of DS until successful dialysis was obtained in two sessions at the same dose. In phase 2, individualized DS doses were validated by a randomized crossover comparison with the individual heparin dose of each patient. In phase 3, each patient underwent 24 consecutive dialyses with DS over 8 weeks. Successful dialysis was defined as completion of the procedure without visible clot formation in the bubble traps and lines or a greater than 20% decrease in dialyser capacity. Dialysis efficiency (decrease in serum urea and creatinine, Kt/V), APTT prolongation, bleeding time, and DS plasma concentrations were also assessed. Results: Phase 1: successful dialysis was achieved in nine patients with 4 mg/kg DS as a predialysis intravenous bolus followed by continuous infusion of 0.65 mg/kg/h. One patient required 5 mg/kg plus 1.3 mg/kg/h. Phase 2: no statistically significant differences were found between DS and heparin in any of the investigated variables. Residual dialyser capacity and dialysis efficiency indexes indicated equivalent efficacy. Phase 3: residual dialyser capacity and dialysis efficiency did not change with time. There was no accumulation of DS in plasma. No bleeding or thrombocytopenia were observed. Conclusions: The dose of DS can be individually titrated to suppress clot formation during haemodialysis as efficiently as with individualized heparin. Such an individualized DS regimen maintains its anticoagulant efficacy and is safe in prolonged use. Key words: anticoagulation; clinical trial; dermatan sulphate; haemodialysis; heparin      

Severe glomerular epithelial cell damage does not prevent passive Heyman nephritis in rats.

Analysis of the local cell-mediated immunity within the central nervous system is limited by the small amount of material available. In the present report we describe that T lymphocyte clones can be expanded directly from the cerebrospinal fluid (CSF) using T cell growth factor and irradiated feeder cells. Without in vitro restimulation such clones can reproducibly be generated from fresh or cryopreserved CSF lymphocytes. From a patient with tuberculous meningitis, T lymphocyte clones were obtained that showed tuberculin (PPD) specific proliferative responses restricted by a single HLA-DR antigen. One of these clones was restricted by an antigen different from the serologically defined HLA-DR since this clone recognized PPD only on autologous but not on HLA-DR matched monocytes. These experiments show that T lymphocytes involved in the in situ immune response can be cloned directly from the site of inflammation.     

Candesartan pretreatment is cerebroprotective in a rat model of endothelin-1-induced middle cerebral artery occlusion

Endogenous levels of angiotensin II (Ang II) are increased in the cortex and hypothalamus following stroke, and Ang II type 1 receptor blockers (ARBs) have been shown to attenuate the deleterious effects in animal stroke models using middle cerebral artery (MCA) intraluminal occlusion procedures. However, the endothelin-1 (ET-1)-induced middle cerebral artery occlusion (MCAO) model of cerebral ischaemia is thought to more closely mimic the temporal events of an embolic stroke. This method provides rapid occlusion of the MCA and a gradual reperfusion that lasts for 16–22 h. The aim of the present study was to evaluate whether systemic administration of an ARB prior to ET-1-induced MCAO would provide cerebroprotection during this model of ischaemic stroke. Injection of 3 μl of 80 μ m ET-1 adjacent to the MCA resulted in complete occlusion of the vessel that resolved over a period of 30–40 min. Following ET-1-induced MCAO, rats had significant neurological impairment, as well as an infarct that consisted of 30% of the ipsilateral grey matter. Systemic pretreatment with 0.2 mg kg⁻¹ day⁻¹ candesartan for 7 days attenuated both the infarct size and the neurological deficits caused by ET-1-induced MCAO without altering blood pressure. This study confirms the cerebroprotective properties of ARBs during ischaemic stroke and validates the ET-1-induced MCAO model for examination of the role of the brain renin–angiotensin system in ischaemic stroke.     

Effects of hemodialytic treatment on uremic polyneuropathy

Summary The involvement of the peripheral motor and sensory nerve, at least on a subclinical level, is a nearly constant event with chronic renal failure. The study of the motor and sensory propagation velocity indicates that a widespread functional lesion of the axon with a peripheral point of attack and secondary demyelination, may be the basic pathogenetic event of uremic polyneuropathy. Prolonged hemodialytic treatment is substantially unable to influence the evolution of uremic polyneuropathy. The electrophysiological follow-up study of the peripheral nerve does not seem to be an index of adequate dialysis.

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Zusammenfassung Die Beteiligung des peripheren motorischen und sensiblen Nerven, zumindest subklinisch, ist bei chronischer Niereninsuffizienz Regel. Die Untersuchung der motorischen und sensorischen Erregungsleitungsgeschwindigkeit spricht dafür, daß bei der urämischen Polyneuropathie als wesentliches pathologisches Geschehen das Axon besonders distal ausgedehnt betroffen ist mit einer sekundären Demyelinisation. Auch langdauernde Hämodialyse scheint nicht in der Lage zu sein, die Entwicklung der urämischen Polyneuropathie zu beeinflussen. Die elektrophysiologische fortlaufende Kontrolle des peripheren Nerven scheint nicht ein brauchbarer Parameter für eine wirksame Dialyse zu sein.

     

Factor VIII--related protein on vascular intima of patients with chronic renal failure and prolonged bleeding times.

To determine whether the prolonged bleeding time so common to chronic renal failure (CRF) was due to defective factor VIII-related activities, as in von Willebrand's disease, vascular-factor VIII-related protein was measured in patients with CRF. Factor VIII-related protein was detected by immunofluorescence on the vascular intima of all 13 patients with CRF and greatly prolonged bleeding times. This protein was also present on the vascular intima of a patient with CRF and moderate von Willebrand's disease. These findings support a previous suggestion that the disturbed haemostasis in patients with CRF is not linked to defective factor VIII-related activities.     

Complication of cochlear implantation surgery

After experiencing gradual, progressive sensorineural hearing loss, a patient underwent cochlear implant (CI) surgery. Postoperatively, the patient experienced vestibular symptoms with no improvement in hearing. High-resolution temporal bone CT scanning demonstrated extracochlear positioning of the CI electrode in the superior semicircular canal.     

Management of myeloma kidney: an anti-light-chain approach

This report describes the course of 23 patients with multiple myeloma and severe renal failure treated with a combination of plasmapheresis, chemotherapy, and supportive measures. Eight of ten patients with acute renal failure (ARF) obtained recovery of renal function, and in five of them serum creatinine concentration returned to normal. The remaining two patients died before the effect of treatment could be evaluated. Eleven of 13 patients with chronic renal failure (CRF) had substantial, albeit incomplete, improvement in renal function. The extent of functional recovery appeared to depend on the type of renal lesions, probably related to the duration of exposure to light chains. The median survival of the whole series of patients was 9 months, and five patients lived longer than 3 years. No clear-cut difference in survival was found between the group with ARF and that with CRF, although the latter presented higher values of serum creatinine at the time of diagnosis and residual renal insufficiency after the completion of treatment. Moreover, no significantly different survival times were found when the group with complete recovery of renal function was compared to that with minor improvement. Thus, renal failure, with the availability of effective forms of treatment of uremia, did not play a major prognostic role in our series. In contrast, the response to chemotherapy appeared to be the outstanding factor conditioning the duration of survival in these patients.