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Biomedical subjects

H Klinkmann

Publications and source records attributed to H Klinkmann.

At least 109 records · Page 6Linked to original sources
PubMed1987

[Noninvasive monitoring of pneumatically driven blood pumps based on measurements of air volume flow in the drive hose].

A computer-assisted measuring system for the noninvasive control of pneumatically driven blood pumps in the artificial total heart replacement and in assist-systems is described. Air volume current measurements with heat wire anemometer in the driving tube underlie as principle. The technique takes into consideration losses of valves, depending upon driving parameters and central circulatory parameters. The dependences established base on measurements at the circulation model. The methods demonstrated allow to qualitatively characterize the signals of the air volume current in the driving tube and approximatively to determine central circulatory parameters on the basis of comparative measurements at the circulation model. Animal-experimental experiences confirm the necessary application of such systems for the measurement of the cardiac output and for the control of the pumping function of pneumatically driven blood pumps. Analyses at the circulation model let expect a measuring error for the volume of output smaller than 20%. By increased measuring exactness of the heat wire anemometer this error can be diminished. For final evidence concerning the measuring exactness animal-experimental investigations and comparisons with reference techniques are provided.

Algorithms↗
PubMed1987

Adsorption of immunologically relevant molecules--its present and future.

The development of numerous adsorbents of various types oblige us to define the used terms. Adsorbents functioning on the same principle as that of the binding between antigen and antibody should be designated as specific adsorbents or immunoadsorbents. All other kinds of adsorbing materials act more or less selectively. A review is given concerning investigations about selective adsorbents. The removal of IgG antibodies is possible with adsorbents of the protein A type. Synthetic materials with IgE and IgM binding properties are presented and are under development. The blocking of the complement system by binding certain components and breakdown products can be a worthwhile feature in view of the biocompatibility of adsorbing materials.

Animals↗
PubMed1987

In vitro investigations with selective adsorbents for IgE and IgM.

In vitro studies were carried out with IM-T. This adsorbent consists of polyvinyl alcohol joined with tryptophan side chains and was delivered by ASAHI Medical Co., Ltd., Tokyo/Japan. It was found that IM-T binds immunoglobulins G and M and also immune complexes only moderately but IgE was adsorbed in remarkable amounts. A clear dose-dependent was adsorbed in remarkable amounts. A clear dose-dependent manner of the IgE adsorption could be stated. Kinetic studies revealed that the binding was only slow and gradual.

Animals↗
PubMed1987

A clinical study on different cellulosic dialysis membranes.

A controlled clinical study was performed over a period of 8 weeks in two dialysis centres (Rostock, GDR, and Munich, FRG). The aim was to compare a dialysis membrane made of modified cellulose (Hemophan) with classical regenerated cellulose (Cuprophan). Dialysers containing these membranes, together with a cellulose acetate dialyser, were therefore incorporated in a cross-over programme and clinical and biochemical investigations undertaken. The efficacy of the modified cellulosic membrane with respect to urea and creatinine clearance was shown to be comparable to that of regenerated cellulose and cellulose acetate. However, modified cellulose showed an increased clearance for inorganic phosphate, significantly different from that demonstrated by both regenerated cellulose and cellulose acetate. Blood compatibility studies, which included the assessment of C3a activation and the reduction of white blood cell (WBC) and platelet count, clearly demonstrated that in comparison to regenerated cellulose, modified cellulose resulted in significantly less complement activation and WBC reduction. Similarly in comparison to cellulose acetate, modified cellulose showed reduced complement-activating and WBC-reducing properties. The reason for the improved blood compatibility of modified cellulose is not, as was originally assumed, related to binding of complement-inhibiting heparin, but appears instead to be due to the substitution of hydroxyl groups of regenerated cellulose.

Biocompatible Materials↗
PubMed1987

[Recommendations for a clinical classification of chronic glomerulonephritis].

As a result of the long-term treatment of 360 patients with histologically ascertained glomerulonephritis including 41 dead patients who had suffered from uraemia a clinical classification of the chronic glomerulonephritis (Ratner, M.) is presented. In detail 5 types of clinical course are characterized: Nephritic types of course: maximally active nephritic type of course, active nephritic type of course, inactive nephritic type of course. Nephrotic types of course: nephrotic type of course without hypertension, nephrotic type of course with hypertension. The elaborated clinical classification allows conclusions to underlying renal histology, tendency of the progression of the disease and prognosis, including survival time.

Adolescent↗
PubMed1986

[Current status and future perspectives of extracorporeal blood purification].

After the description of the main indications for an extracorporeal blood purification the authors enter the at present existing and applied detoxication methods on the basis of membranes and absorbents, respectively. A short characterization of the most important membrane separation techniques peritoneal dialysis, haemodialysis, haemofiltration, haemodiafiltration and membrane plasma separation, respectively, is given. Moreover, an estimation of the cascade methods is given, i.e. the application of several separation filters. As adsorptive methods the haemoperfusion and the plasma perfusion, respectively, are assessed with their advantages and disadvantages and the authors enter the possibility of the combination of the procedures mentioned. As problems which are to be solved still in the first place the deficient blood compatibility, selectivity, individualization and continuity are discussed and ways of solution are shown which up to now are entered upon for the improvement and optimization, respectively, of the problems mentioned. In this case particularly the surface modification of materials and the search for new materials, respectively, as well as the use of special models is emphasized as important for future. In the field of selectivity adsorptive methods are to be developed in the first place which without danger of complications remove relevant metabolites from the organism. For the future is above all to be reckoned with the further development of so-called hybrid organs, since such organs may best repeat biological processes.

Acute Kidney Injury↗
PubMed1986

[Review. The status of plasmapheresis and apheresis].

The paper surveys the technical and clinical development of plasmaexchange therapy. Until today there is no agreement on a unique treatment protocol, the variation ranges from 3-4 treatments in multiple sclerosis to biweekly chronic treatment in hypercholesterolaemia. An exchange volume of 1-1.5 of the plasma volume is recommended. Despite occasional complications, mostly due to replacement fluid, the method is regarded as safe. The first clinical application dates back to 1952, when Adams reported on the treatment of hyperviscosity syndrome. With rheumatoid arthritis plasmaexchange therapy of immunological mediated diseases started in 1963. In the following years a lot of enthusiastic case reports caused a general therapeutic optimism which was to be corrected by controlled trials. There is no proven benefit of plasmapheresis in rheumatoid arthritis and rapid glomerulonephritis for instance. For lymphoplasmapheresis in rheumatoid arthritis and for plasmapheresis in multiple sclerosis and renal graft rejection the results are contradictive. The paper discusses the different indications for apheresis therapy including hematologic disorders to be treated with plasmapheresis or cytapheresis.

Autoimmune Diseases↗
PubMed1986

[New results concerning the effectiveness of therapy of chronic glomerulonephritis. Results of cytostatics-anticoagulants-aggregation inhibitors, cystostatics-anticoagulants-aggregation inhibitors-prednisone and cystostatics-prednisone therapy, derived from a retrospective study].

The indication and effectiveness of the immunosuppressive therapy of chronic glomerulonephritis is now as ever controversial. As a result of a retrospective therapy study in an at least one-year therapy with cytostatics, thrombocyte aggregation inhibitors and anticoagulants (CAA-therapy, n = 27), additional prednisone therapy (CAAP-therapy, n = 95) and cytostatic-prednisone therapy (CP-therapy, n = 33) we find favourable results for the CAA/CAAP-therapy in the nephrotic syndrome and glomerulonephritides with distinct clinical exacerbation also in sclerosations in histology. Clinically inactive nephritides with exclusive urinary findings and sclerosations cannot be influenced therapeutically.

Anticoagulants↗
PubMed1986

[Results of a multicenter study of the early detection of glomerulonephritis. 1].

In the framework of a multicentric retrospective study between selected clinics of the Republic Austria and the GDR anamnestic, clinical and paraclinical data were investigated in their valency for the early recognition of glomerulonephritis. Data of 583 patients were evaluated. Hereby it was shown that independent of the size of excretion and the reproducibility the findings "proteinuria" are of particular significance for the early recognition. The serological investigations usually performed within the diagnostic of glomerulonephritis proved as insignificant for the early recognition. Since the establishing of an exact diagnosis is up to now possible only with the help of invasive methods, a call on research is made to develop reliable, non-invasive diagnostic methods.

Adult↗
PubMed1986

Preclinical evaluation of haemosorbents.

The selection of assessment procedures for the preclinical evaluation of haemosorbents and the relationship between such procedures and the intended application are exemplified by examination of the design and utilization of procedures based on the rat. Procedures are described for haemoperfusion and for membrane plasma separation followed by on-line sorbent treatment of plasma (plasma perfusion). These procedures are suitable for single or repeated use, with the animal in an unrestrained and conscious state. The relevance to the intended application is demonstrated with respect to artificial liver support by the ability of rat extracorporeal circuits to provide information on the relationship between sorbent properties and liver regeneration as determined by the proliferative response following partial hepatectomy.

Adsorption↗
PubMed1986

Surgical principle in total artificial heart--an experimental review.

Based on implantation experiments in calves resulted some experiences for the implantation technic of artificial hearts. After resection of the natural ventricles and of the valvular parts of the aorta and pulmonary artery the connectors should be adapted and implanted. The first connected left ventricle get a caudal-lateral traction especially under supervision of the pulmonary veins and optimal development of the aorta. During connection of the right ventricle it is necessary to check up the inflow - and outflow tract situation. May be, the left ventricle get with this maneuver an unfavourable caudal kinking. Careful preparation and splitting of the pericardium is necessary to avoid obstructions for the venous flow. The closing of the chest and initial changes in position of the animal may alternate good positions of the heart, if the resection as well as preparation, adaptation and bedding don't remarked the discussed principles. One of the most relevant aspects in achieving the consistent survival of an animal undergoing the experimental implantation of a total artificial heart is obviously related to the correct anatomic placement of prosthetic ventricles inside the chest. In this case, the skillful surgical procedures based on an established surgical principle are considered to be attributable in obtaining the optimal hemodynamic situation. Description of the surgical procedures has been made elsewhere. However, it has been difficult to find a well defined surgical principle although particular milestone has already been made by a clinical application of the total artificial heart in 1982. Although the presently available prosthetic ventricles generally fit better in the chest, the problems in design and size of the prosthesis still exist.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Surgical Procedures↗
PubMed1986

Experiments with continuous hemofiltration and hemofiltrate regeneration in the rat.

Experimental studies were made with continuous hemofiltration treatment for bilaterally nephrectomized rats and initial observations regarding the effects of such treatment on leukocyte and thrombocyte counts are reported. Hemofiltration of unanesthetized rats able to move freely within their cage could be continued for up to 30 h using a pump-driven ECC system. Blood parameters recorded during this treatment indicate that the detoxification was effective. In another series of experiments the water and electrolyte reabsorption capacity of the colon ascendens of healthy rats was tested by continuously supplying NaCl solution into the colon via a fistula. A large proportion, if not all, of the hemofiltrate can be discharged into the colon without diarrhoea. A final series of experiments showed that the three-stage operation (implantation of permanent catheters, connection of a permanent intestinal fistula and bilateral nephrectomy) is possible with the rat.

Animals↗