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Biomedical subjects

W Samtleben

Publications and source records attributed to W Samtleben.

At least 55 records · Page 3Linked to original sources
PubMed1991

[MRT in dialysis-associated destructive spondylarthropathy of the atlantoaxial region].

Destructive bone and joint diseases in patients on longterm haemodialysis increase in frequency and are often caused by beta 2-microglobulin-related amyloid deposits. Due to the excellent visualisation of amyloid, MRI with T1-weighted and out-of-phase gradient recalled long TR images is the diagnostic modality of choice. 5 patients, 13 to 21 years on haemodialysis, were investigated. In four patients we found involvement of the atlantoaxial region, one patient was asymptomatic, the other three had severe neurological deficiencies.

Adult↗
PubMed1989

Recombinant human erythropoietin in nephrology.

rEPO therapy provides a unique opportunity to correct anemia in end-stage renal failure patients. Complete correction of the anemia, although possible, has some obvious disadvantages over a partial correction with a target hemoglobin of 10-13 g/dl or a hematocrit of 30-35%, respectively. Unresponsiveness to rEPO seems to be rare; in most cases the predicted hemoglobin increase could be seen as soon as an underlying iron deficiency was treated adequately. Blood loss and aluminum toxicity are the next most frequent reasons for an inadequate response to rEPO. Hypertension (and its complications) as well as fistula clotting are the most important side-effects which require close attention when patients at risk for these complications are treated with rEPO.

Acute Kidney Injury↗
PubMed1987

Ex vivo biocompatibility evaluation of a new modified cellulose membrane.

To evaluate membrane biocompatibility, an open loop ex vivo model was designed simulating the hemodialysis procedure. Blood was withdrawn continuously from healthy nonuremic donors, heparinized, and pumped through a module containing the membrane to be studied. C3a generation in the module was determined at various time points comparing the cuprammonium cellulose (CC) membrane and four types of modified cellulose (MC) membrane, each with a different degree of hydroxyl (OH-) group substitution. In other studies, C3a generation in the ex vivo mode was compared with that during in vivo dialysis. In the ex vivo model, C3a generation with MC membranes was reduced by 70% compared with CC. However, within the MC group, the degree of C3a generation did not correlate with the degree of OH-group substitution. In vivo studies confirmed the reduced degree of C3a generation with the MC membrane compared with CC. Additionally, validation studies using the CC membrane showed excellent agreement between C3a generation during ex vivo perfusion and in vivo dialysis. The results suggest that a group of new MC membranes causes substantially less complement activation than the CC membrane but that the degree of complement activation with various subtypes of MC membranes is not related to the degree of OH-group substitution.

Anaphylaxis↗
PubMed1987

Ex vivo and in vivo protein A perfusion: background, basic investigations, and first clinical experiences.

During the past several years clinical protein A perfusion has attracted much attention because it allows to selectively remove IgG subclasses 1, 2, 4 and probably IgG-containing immune complexes, and has a tumoricidal effect in experimental animals and in some cancer patients. Due to several drawbacks, this therapy is not yet generally accepted. Our first experience with laboratory and clinical protein A perfusions confirms several limitations of this new apheresis therapy. Plasma IgG extraction in the ex vivo system under investigation and during clinical application of protein A perfusion reached a 10:1 ratio of grams IgG removed per gram solid-phase protein A only in 2 of 5 runs. Nevertheless, the absolute amount of IgG removed was very low in all runs due to the restricted protein A load (maximum 200 mg) per column. Removal capacity can be increased by a two-column switch-over system with subsequent perfusion and elution. Furthermore, the side effects observed in both in vivo treatments exceeded by far those of other extracorporeal therapies and had not been observed in more than 1,200 unselective plasma exchanges or in 50 cascade filtrations in our center. C3a generation in protein A perfusion is, however, comparable to cascade filtration, but exceeds that of unselective plasma exchange and is lower than in hemodialysis. Consequently, side effects in protein A perfusion cannot be correlated with the total amount of anaphylatoxin generated but may be due to a leakage of protein A or contaminants. Clinical application of protein A perfusion needs a more detailed elaboration in respect to biocompatibility, removal capacity, and the significance of the induced biological effects.

Adsorption↗
PubMed1986

[Are C1q binding immune complexes appropriate as markers for infected ventriculo-atrial shunts?].

Routine C1q-fluid phase radioimmunoassay identified high levels of C1q-binding immune complexes in 3 patients with infected ventriculoatrial shunts (VAS). Accordingly, C1q-binding activity was prospectively studied in additional 36. VAS patients to learn whether the observed immune complex activity was secondary to bacterially contaminated shunts or was a normal sequela of continuous intravenous infusion of cerebrospinal fluid into the vascular space. Pathological levels of C1q-binding activity were detected in only 3 out of 32 patients without evidence of shunt infection. However, extremely high C1q-binding activities were measured in 4 more patients with proven shunt infections. Thus, elevated levels of C1q-binding immune complexes correlate with infected VAS. As shunt infection is otherwise difficult to detect, serum C1q-binding activity may prove to be a valuable diagnostic tool for this condition.

Adolescent↗