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Biomedical subjects

H Klinkmann

Publications and source records attributed to H Klinkmann.

At least 127 records · Page 7Linked to original sources
PubMed1985

Blood-membrane interaction: C3a, an indicator of biocompatibility.

An interest in hemodialysis-related patient symptomatology dating back to the beginnings of maintenance hemodialysis (HD) therapy prompted our investigations to determine the etiology of such discomfort. Since the discovery by Craddock et al (1) of the activation of the alternative complement pathway by hemodialyzer membrane, our efforts toward defining the relationship of symptoms to complement activation have been done in collaboration with the Minnesota group. Results of an earlier blinded study, (2) and continuing investigations of HD membranes provide data which support the contention that complement activation, although not necessarily etiologic in the symptoms related to dialysis, serves as an indicator of membrane compatibility. These newer data reveal C3a rises in vivo and in vitro by a Japanese processed cuprammonium membrane for dialysis to be similar to cuprophane. In vivo C3a elevation using Travenol CA-110 hemodialyzers of cellulose acetate are significantly lower and are similar to earlier results obtained by cellulose acetate of CD manufacture.

Cellulose↗
PubMed1985

Cell electrophoretic investigations of peripheral blood lymphocytes during hemodialysis with different membranes.

Determining the relative percentage of LMC in PBL histograms of RDT patients during hemodialysis we observed a temporary decrease of the LMC proportion during the first 15 minutes of hemodialysis using Cuprophan in contrast to AN 69S and MC Cellulose. These results correlate with the increase of C3a plasma concentration and the decrease of total count of granulocytes. In all investigated RDT patients higher proportions of LMC could be found in relation to healthy donors already before dialysis treatment. Our study therefore seems to indicate that the application of cell electrophoresis is a useful method for the characterization of lymphocytes during extracorporeal circulation as an additional parameter of blood compatibility.

Acrylic Resins↗
PubMed1984

[Information content of endogenous creatinine parameters for kidney function diagnosis in glomerulonephropathies].

The functional-diagnostic findings, namely serum creatinine level, 24-h creatinine clearance, 1-h (morning) creatinine clearance and inulin clearance, of 58 glomerulo-nephropathy patients were evaluated using regression and correlation analysis. For clinical nephrology it is recommended not to measure 24-h creatinine clearance. For the purpose of diagnosing kidney function the information content of the serum creatinine level is sufficient if the hyperbolic relation to the GFR is taken into account. For clinical-scientific nephrology standardized short-term creatinine estimation in combination with direct or indirect GFR measurement (and other parameters of kidney function) is advisable.

Creatinine↗
PubMed1984

[Behavior of copper and manganese in serum in hemodialysis].

The extent to which chronic dialysis alters the serum copper and manganese content was examined. The copper content was not significantly altered, whereas the level of manganese in the blood rose highly significantly. This manganese originates from the dialysis fluid. The behaviour of the manganese level during dialysis treatment suggests that the element is deposited in the body. Its transport is clearly connected with protein, since the manganese is not found in the ultrafiltrate. The is no fear of manganese intoxication.

Copper↗
PubMed1984

[An improved connecting system for artificial hearts].

The certain connection of the artificial ventricles to the vascular system has a decisive importance in the implantation of an artificial heart. Demands concerning tightness, reliability, easy attendance, and anatomic fit are to be considered especially in the construction of a suitable connecting system. A modified bayonet system came in use. The connection between the artificial heart and the vascular system is placed here by distortions of a tightening ring.

Animals↗
PubMed1984

Activated charcoal and resin haemoadsorbents: in vitro drug removal and blood compatibility studies.

An investigation has been made of the drug removal properties and blood compatibility of activated charcoal and resin haemoadsorbents . The adsorbents were Norit RBX1 peat-based extruded charcoal, spherical charcoal as used in the Sorin Biomedica Detoxyl 2 column and 2 cross-linked polystyrene-based macroreticular resins. Drug removal properties were assessed in terms of in vitro adsorption efficiency of each adsorbent for 11 different drugs. The blood compatibility of the charcoals and macroreticular resins was evaluated in an in vitro haemoperfusion circuit by measuring the changes in platelet and leucocyte levels in human blood caused by contact with the adsorbent. The results of the investigation indicate advantages in using spherical charcoal haemoadsorbents .

Blood Grouping and Crossmatching↗
PubMed1983

Heparin binding and release properties of DEAE cellulose membranes.

Two cellulose-based membranes, containing 5 and 20% N, N-diethyl-aminoethyl cellulose (DEAE) respectively, were investigated for ionic attachment of heparin and heparin release. Heparinization was achieved by recirculation of a heparin-containing glycine buffer over each membrane. Heparin was determined by chemical analysis or by 99mTc labelling. The heparin uptake was shown to be linearly dependent on the heparin content in the contacting fluid. Heparin release was studied by contacting heparinized membranes with saline, glycine buffer, phosphate buffer and plasma. Incubation with plasma brought about the release of 50% of the attached heparin. Crosslinking of the heparinized membrane with glutaraldehyde reduced the heparin release by one half. The release reaction is more critical in the case of increased heparin uptake and a more efficient immobilization of heparin appears necessary.

Cellulose↗
PubMed1983

Symptoms and activation of granulocytes and complement with two dialysis membranes.

Complement (C) activation, neutropenia, and mild pulmonary dysfunction attend hemodialysis (HD) with cellophane [for example, cuprophan (Cu)] membranes. While usually asymptomatic, these phenomena may cause distress in patients with cardiopulmonary disease, and "start-up" symptoms of HD might be mediated by C-stimulated granulocytes (PMNs). Cellulose acetate (CA) hemodialysis membranes have been devised and claimed more blood compatible than Cu. In a blinded series of HD patients, pruritus, fatigue, and sense of well-being were each scored statistically more favorably by the patients during HD with CA than during HD with Cu (P less than 0.05). Postulating that less C activation might underlie the benefit, we showed that neutropenia was less severe with CA (nadir 77.6% of initial count, +/- 4 SEM) than with Cu (38.3% +/- 2.9; P less than 0.01). In vitro, incubation of CA membranes with plasma led to less C3 conversion (20% vs. 40%), less PMN aggregating activity (5.9 ZAP units vs. 36.3) and less decrement in CH50 (6.5% vs. 22%) than like incubations of Cu. C activation was also less potent in vivo: During HD plasma C3a rose from a mean 401 ng/ml to a peak 6,325 in patients on Cu dialyzers, but from 426 to only 3,637 in patients on CA devices (P less than 0.05). Time-course studies suggested CA was initially as potent an activator as Cu but rapidly lost ability to activate C, possibly because of saturation of C3b binding sites. As an index of PMN activation, we also assayed plasma lactoferrin and found levels significantly higher during Cu than CA dialysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaphylatoxins↗
PubMed1983

[Immunoadsorption using Staphylococcus aureus, COWAN I strain].

Immunoadsorbents bind immunoglobulins, immunocomplexes or immunocytes. Their clinical use could become a new therapeutic principle for diseases in the pathogenesis of which antibodies or immunocomplexes play an important part. Immunoadsorbents are also being tested in the hope that they can at least partially replace the plasmapheresis-plasma exchange therapy at present practised. A report is given on in-vitro studies using protein-A-bearing staphylococci, strain COWAN I. The bacteria bind IgG selectively, IgM to a small extent, IgA, IgD and IgE hardly. The majority of the other plasma proteins tested (e.g. albumin, transferrin, ceruloplasmin, alpha-2-macroglobulin, beta-lipoprotein, alpha-2-glycoprotein, alpha-1-antitrypsin) are bound only non-specifically and in small quantities. The staphylococci can react with acid solutions (glycin-HCl buffer, acetic acid) in several ways. The activation of the complement system by IgG binding to protein A is one of the problems to be solved before immunoadsorbents an be used clinically.

Antigen-Antibody Complex↗
PubMed1983

[Complications in the treatment of chronic glomerulonephritis].

In a retrospective study involving 97 patients with histologically confirmed glomerulonephritis the complications which led to the breaking off or changing of an immunosuppressive therapy [Prednison monotherapy (n = 39), Prednison cyclophospohamide therapy (n = 13), Prednison azathioprin therapy (n = 49), Indometazin therapy (n = 25)] were examined. Of 97 patients treated repeatedly over long periods, 22 suffered complications which caused the therapy to be broken off or changed. Because of the risk involved, immunosuppressive therapy of glomerulonephritis should only be practised by institutions specializing in nephrology.

Azathioprine↗
PubMed1983

[Possibilities for using extracorporeal circulation in the rat].

An extracorporal system of freely mobile, unanaesthetized rats is presented. This model was used in experiments on the biocompatibility of silicone rubber and new types of hollow membranes. The results confirm a sensitive reaction of haematological parameters to various test substances, thus indicating that the model is very suitable. Carrying out a membrane plasma separation in rats makes it possible also to use rats for studies on detoxification and thus to use the advantages offered by this experimental animal to the full.

Animals↗
PubMed1983

[What is the current outlook for an implantable artificial kidney?].

Considering the homeostatic demands made by the organism on an artificial eliminating substitute kidney system, it seems that the haemofiltrative principle for transporting matter is the most suitable for simulating the natural glomerular kidney function in an implantable artificial kidney. Biophysical laws can be used to influence long-term filtrative efficiency and the blood-flow in the haemofilter system can be controlled by technical feedback regulation. Endogenically, the filtration process is, in terms of energy, driven by the aterial blood pressure (specifically, by the trans-membrane pressure thus generated). The definitive ultrafiltrate treatment takes place by intestinal reabsorption and elimination of the end products, whereby these functions may be assisted by the use of sorbents etc. or an adequate substitution therapy if reabsorption is insufficient. These processes can reasonably be triggered by neurohormonal feedback regulation if the homeostasis situation is greatly disturbed by the haemofiltration process. The implantable artificial kidney is thus a biochemical hybrid kidney.

Animals↗
PubMed1983

[Experimental development of hollow cellulose membranes for blood detoxification].

In recent years there have been repeated demands in medical circles for new membranes for various purposes. At present attention is focussed on the development of membranes for the detoxification of blood. Using available technology and resources, it seemed appropriate to develop such hollow membranes out of cellulose by the viscose process. It is possible to give the membrane a suitable structure according to the use intended. The transport of matter and ultrafiltration can be influenced by varying the influence parameter in the spinning process via changes in the pore structure. In this way it is possible to produce hollow membranes for dialysis or ultrafiltration, with varying grades of permeability, out of cellulose by the viscose process.

Blood↗