Biomedical subjects
Publications and source records attributed to W Opferkuch.
A new method to estimate the bactericidal activity of peritoneal macrophages is described. This method allows to calculate with great accuracy the number of phagocytised bacteria per macrophage. In serial experiments different degrees of activation of macrophages in respect to their bactericidal activity against listeria monocytogenes has been shown.
Patients on chronic hemodialysis may suffer from a latent protein deficiency, and therapy with essential amino acids has been recommended. In a double blind cross-over study, 13 hemodialysis patients received orally 15.7 g of essential amino acids daily over a 3-month period. Patients were on a liberal diet, containing 1 g of protein per kilogram of body weight per day. Hemodialysis was adequate. Therapy resulted in an increase in urea, uric acid, C3 c complement factor and a fall in C4. Lysine levels increased and phenylalanine fell. Malnutrition could not account for the observed metabolic changes, which are more likely due to uremic metabolic disturbances. A liberal diet of 1 g of protein per kilogram of body weight appears sufficient for patients on hemodialysis. Treatment with essential amino acids offers no advantage.
The interaction of the first component of complement with two serum-sensitive strains of Escherichia coli and Klebsiella pneumoniae was studied. It could be demonstrated that highly purified C1, free of immunoglobulin G and immunoglobulin M, binds to E. coli or K. pneumoniae. C1 binding was also found with specifically absorbed human serum, after incubation of bacteria with normal serum in the presence of ethylenediaminetetraacetate or agammaglobulinemic serum; the number of C1 molecules taken up by the bacteria was not influenced, indicating that C1 binding was independent of naturally occurring antibodies. C1 bound to bacteria was still able to cleave C4, the natural substrate of C1. From these observations, it is concluded that C1 in an enzymatically active state can be bound directly to bacteria independently of antibody.
The Autobac I provides an automated method for the rapid measurement of antimicrobial susceptibility of fast growing pathogenic microorganisms. To check instrument accuracy, 477 cultures were tested by the Bauer-Kirby method for comparison. According to the DIN limits, the results were comparable in 81.8%, whereas within the NCCLS limits the agreement was 86.5%. The discrepancy was found to be due to incorrect disc mass and different limits of inhibitory zone diameters. Another reason for disagreement seemed to be the incubation time, since its influence on the results varied when different bacterium/antibiotic combinations were used.
The multitude of antibiotics is divided into groups according to their chemical origin and therapeutical demands. The knowledge of antimicrobial activity and side effects is essential for an effective antibiotic therapy. Clinical cases are exposed to demonstrate the main rules of antibiotic medication: a) Bacteria with solid or with varying susceptibility ratio; b) susceptibility testing.
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It is intended to summarize the latest research in the complement field. After a short comment on the biochemical behaviour of proteins participating in the complement reaction, biochemistry of the complement reaction itself and its biological activities are described. The question of participation of the complement system in disease is examined by specifying the possibilities to analyse the complement system in clinical problems, and, on the other hand, by giving a review on our latest knowledge of modifications of the complement system in disease.
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Using purified human complement components, the participation of C5 in phagocytosis was investigated. The addition of C5 to EAC 1423 increased both rosette formation and phagocytosis of the intermediates by human polymorphonuclear leukocytes. The opsonizing activity of C5b was not affected after decay of its hemolytic activity. Both C3- and C5-dependent phagocytosis is abolished either in the presence of chelating agents or by pretreatment of the polymorphonuclear leukocytes with trypsin. The enhancing effect of C5b in phagocytosis can be reduced either by further reaction with C6 and C7 or with anti-C5 F(ab)2 fragments.
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The family of an individual was studied who lacks the seventh component of complement in his serum (C7 homozygous deficiency). Both parents are C7 heterozygous-deficient. In this investigation, the following parameters were determined: complement components in functional and immunochemical tests; HLA-A,B antigens, HLA-D (MLC) determinants; the Bf system; glyoxalase I and B cell antigens. No evidence for linkage between the immunogenetic linkage group on chromosome 6 and gene(s) controlling the synthesis of the seventh component of complement was obtained. This is in according with the assumption that only genes controlling components of the initiating rather than the membrane attack unit of complement are linked to the HLA region.
In vitro phagocytosis by guinea pig peritoneal macrophages of immune complexes (EA) was shown to be dependent on IgG antibody in a dose-dependent fashion. C3b enhanced phagocytosis of EA at limited IgG antibody concentrations only. When IgM antibody was used for sensitization of sheep red blood cells (SRBC), phagocytosis and rosette formation did not occur in the absence of bound C3. The polyanion, dextran sulfate 500 (DS), was shown to depress both rosette formation and phagocytosis of EAIgG, C1423 and EAIgMC1423, as well as immune adherence of human group 0 erythrocytes and hemolytic activity of C3. This effect of DS was seen only when it was actually present in the incubation medium.
Phagocytosis of SRBC by guinea-pig peritoneal macrophages is enhanced by opsonizing IgG antibody alone. IgM antibody requires the presence of bound C3. Treatment of C3b coated SRBC with purified C3b inactivator (yielding EAIgM C1423d) does not reduce attachment to, and phagocytosis by, peritoneal macrophages. This finding suggests the existence of a C3d receptor on peritoneal macrophages. EC43b intermediates which have been produced by removing IgM antibody by mercaptoethanol treatment and by subsequent removal of C1 and C2, are phagocytosed despite the absence of IgM antibody. Furthermore, treatment of EC43b with C3b inactivator does not change phagocytosis. Thus, IgM antibody does not appear to be a necessary prerequisite for the stimulation of phagocytosis, C3b or C3d alone being sufficient.
A method is described which allows a quality control for demonstrating mycobacteria in the diangosis of tuberculosis. It does not test the differentiating procedures, but the manner of culturing and concentrating the bacteria by applying a statistical evaluation of serial experiments, thus allowing the statistically proven determination of the bacterial count. For this an evaluation method given by Cavalli-Storza was employed.
Evidence is presented that guinea pig peritoneal macrophages possess membrane receptors able to recognize the C3b inactivator-cleaved third component of complement. This conclusion is based on the finding that rosette formation and phagocytosis by macrophages of EA-IgM-C1423 were equal regardless of whether EA-IgM-C1423 had been pretreated with C3b inactivator or not.
Sheep erythrocytes were sized by an electrical method during lysis by antibody and complement. No volume changes were observed upon to the EAC1-8 cell intermediate. Three steps could be distinguished in the reaction of C9 with EAC1-8 cells: fixation of C9 to EAC1-8 cells, a process which proceeds also at 0 degrees C; temperature-dependent swelling of the EAC1-9 cells; and lysis of the cells. We could show that swelling of the erythrocytes induced by the complement reaction is independent of protein osmotic forces and is caused by an alteration of the erythrocyte membrane.
The serum of a 13-year-old healthy boy was found to be deficient in whole complement activity. The seventh component of complement could not be detected by functional assays whereas the titres of the other components were found within the normal range. An attempt to detect C7 by immunodiffusion against an antiserum to human C7 also failed. The functions of C1-C6 were normal with respect to opsonizing activity, immune adherence, and the ability to generate chemotactic activity. However, those functions that require the whole complement sequence such as bactericidal and haemolytic activity were found to be absent. Furthermore, the occurrence of a C7-inactivating principle was demonstrated in the C7-deficient serum. This principle inactivated C7 both in the fluid phase and in its cell-bound state. Some physicochemical parameters of the inactivator are described and its possible nature is discussed.