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Biomedical subjects

I Petersen

Publications and source records attributed to I Petersen.

At least 109 records · Page 6Linked to original sources
PubMed1985

Complement-mediated solubilization of immune complexes and their interaction with complement C3 receptors.

Some of the molecular events in the complement (C)-mediated solubilization of immune complexes (IC) have been clarified in recent years. The solubilization is primarily mediated by alternative C pathway proteins whereas factors in the classical pathway accelerate the process. Components of the membrane attack complex do not participate in the reaction. Besides affecting the size and solubility of circulating IC the interaction with C factors influences the reactivities of the complexes towards fluid phase reactants and mediates the reversible binding of IC to cellular C3 receptors. Our knowledge of the cellular localization, expression and structure of the C3 receptors, especially the C3b (CR1) receptor, has been considerably extended in the last few years, whereas our understanding of the physiological role of these receptors is still fragmentary. However, it is becoming increasingly evident that impaired solubilization of IC in patients with compromised C function may permit the complexes to deviate from their normal pattern of interaction with C3 receptors probably influencing both the organ distribution and clearance of IC and thereby also their phlogistic potentials.

Antigen-Antibody Complex↗
PubMed1984

Complement-mediated solubilization of immune complexes. Solubilization inhibition and complement factor levels in SLE patients.

Thirty-two of 36 serum samples from 19 SLE patients showed reduced capacity to mediate complement-dependent solubilization of immune complexes (IC). SLE patients with nephritis exerted the lowest complement-mediated solubilization capacity (CMSC) whereas sera from patients with inactive disease gave the highest CMSC values, with three out of four samples within the normal reference range. Thirty-five of the 36 serum samples showed inhibition of CMSC in a newly developed CMSC inhibition assay. The strongest CMSC inhibition was exerted by sera from newly discovered cases of SLE who received no medical treatment and the lowest inhibition by sera from patients with inactive disease. There was a significant negative correlation between CMSC and CMSC inhibition (r = -0.67, P less than 0.001). Sera with low concentrations of C1q, C3, factor B or high C3d levels showed markedly reduced CMSC values. Pronounced CMSC inhibition was observed only in samples with normal or high factor H values. No significant correlation was found between CMSC or CMSC inhibition and circulating IC levels, but pronounced CMSC inhibition was registered only in strongly IC positive sera.

Adolescent↗
PubMed1984

Solubilization of immune complexes in complement factor deficient sera and the influence of temperature, ionic strength and divalent cations on the solubilization reaction.

The complement-mediated solubilization (CMS) of immune complexes (IC) and the initial kinetics (IKS) of this reaction in human sera depleted of or deficient in C2, C3, C8, factors B, P and I were investigated. Sera depleted of B or P and those lacking native C3 or factor I showed virtually no CMS whereas the IKS and CMS capacity of a C8-deficient serum were within the reference range. The IKS of a C2-deficient serum was markedly retarded while the CMS capacity was normal. Addition of C2 normalized the kinetics of the reaction. There was a good correlation between the kinetics of CMS determined by a radioassay and kinetic data for the binding of C3b to preformed immune complexes. The CMS capacity reached maximum at 39-41 degrees C and at an ionic strength of approximately 0.20 mu. Selective chelation of Mg2+ completely abolished the CMS of IC. Maximal CMS was observed at Mg2+ concentration of about 2mM. Chelation of Ca2+ in serum by Mg2+-ethylene glycol tetraacetic acid reduced the CMS capacity by up to 50% and the IKS was markedly retarded. Varying the Zn2+ or Mn2+ ion concentrations in serum influenced neither the IKS nor the CMS capacity.

Antigen-Antibody Complex↗
PubMed1983

Estradiol-induced hepatic protein synthesis and transaminase activity in the male flounder, Platichthys flesus (L.).

A continued accumulation of vitellogenin was observed in the serum through 28 days after administration of spaced large doses of estradiol. The level of estradiol in the serum reached a maximum on Day 4, followed by a continued decrease until a basal concentration was reached at Day 15. The estradiol treatment increased the in vitro hepatic protein synthesis activity, measured as polyphenylalanine synthesis per unit cytoplasmic RNA, within 2-4 days reaching a maximum after 7 days. The effect was transitory and reduced to less than 50% within 15 days. After restimulation a second rise in protein synthesis activity was observed. The cellular content of bulk RNA i the liver showed a slow but steady accumulation through the 28 days. The specific activity of glutamate-oxaloacetate transaminase and glutamate-pyruvate transaminase in the liver decreased 35 and 20% relative to control, respectively, within 7 days after the first stimulation and again 14 days after restimulation. The concentration of serum protein showed a steady increase throughout the experimental period. The concentration of serum ninhydrine positive substances was lowered to 50% relative to the controls within the first 7 days after start of treatment with hormone.

Alanine Transaminase↗
PubMed1983

Intratypic differentiation of poliovirus strains by enzyme-linked immunosorbent assay (ELISA): poliovirus type 1.

A double antibody sandwich-ELISA has been developed for the detection of antigenic differences between wild and vaccine derived strains of Poliovirus type 1. Poliovirus strains antibodies were prepared in rabbits by immunization with virus suspensions of: Sabin LSc2ab (vaccine derived) and Brunhilde and Mahoney (wild types). IgG fractions were purified from antiserum by precipitation with ammonium sulphate and DEAE-Sephadex A50 chromatography. Purified IgG antibodies were used for coating of microtest plates (catching antibodies). The same reagents labeled with horseradish peroxidase were used as conjugates (detecting antibodies). Detecting antibodies were made strain specific by cross-absorption with the heterologous virus strain. Absorbed and non-absorbed detecting antibodies were subsequently used for detection and quantitation of the poliovirus antigen(s) bound to IgG-coated surfaces. Poliovirus laboratory strains and isolates from sixty-six individuals were differentiated intratypically as vaccine derived or wild types when the ELISA was performed using absorbed conjugates. No intermediate strains were found, and all clinical samples tested fell in two distinct categories. Conversely, when detecting antibodies were used before absorption a high degree of homology between wild and vaccine strains was demonstrated and the differentiation between the two groups was poorly achieved. The ELISA has been optimized in terms of specificity and sensitivity. Less than 10 ng of poliovirus antigens could be detected by non-absorbed detecting antibodies whereas 18 ng was the minimal amount detected by the same antibodies after absorption. Preparation of strain specific antibodies did not require a previous concentration of the poliovirus suspension used for the absorption. It is proposed that the developed ELISA is capable of: 1) detection of low amounts of poliovirus antigens in clinical samples, and 2) intratypic differentiation of poliovirus antigens as either vaccine derived or wild types.

Antibodies, Viral↗
PubMed1983

Reduced complement-mediated immune complex solubilizing capacity and the presence of incompletely solubilized immune complexes in SLE sera.

Reduced complement-mediated solubilization (CMS) of pre-formed immune complexes (IC) was demonstrated in sera from 11 out of 12 SLE patients. The presence of incompletely solubilized endogeneous IC in SLE sera was indicated by the following findings: (1) When IC positive SLE sera with reduced CMS capacity were mixed with normal donor sera they inhibited the CMS of the latter sera. (2) Resuspended PEG (2.75%) precipitates obtained from SLE sera inhibited the CMS of normal donor sera. (3) Non-solubilized or incompletely complement solubilized IC in SLE sera give a strong response in the PEG-CC assay for IC. The IC activity of SLE sera was clearly reduced in this assay when the endogeneous IC were solubilized prior to testing. In contrast, sera of 14 rheumatoid arthritis (RA) patients exhibited normal CMS. IC which could be further solubilized by complement were not demonstrable although all RA sera were IC positive.

Adult↗
PubMed1981

Antigenic potency of inactivated poliovirus vaccines.

The potency of inactivated poliovirus vaccines have been determined in vitro using ELISA and the values compared with the in vivo potency as expressed in antibody titres and antigenic extinction limits, revealing three possible expressions of vaccine quality.

Animals↗
PubMed1981

The monitoring of antigen levels during inactivated poliovirus vaccine production: evaluation of filtration techniques.

The use of ELISA to estimate poliovirus antigen concentration has permitted an evaluation of the methodology used in vaccine production and allowed exploration of less wasteful filtration-techniques. The replacement of Seitz-EKS-1B filtration with either Seitz-Supra-EKS or Pall-filtration in the preparation of the vaccine could make a large saving in the total antigen yield, but the results in the safety test excluded their possible use in our process as it stands at the moment.

Animals↗
PubMed1981

Cultivation of second and third passage cells from Cercopithecus monkey kidneys in monolayer cultures.

In order to further reduce the amount of monkeys used for production of inactivated poliovaccine without expensive investments, cultivation of second and third passage cells from Cercopithecus monkey kidneys in monolayer cultures has been attempted. Steep growth curves were obtained for all three passages. But the initial loss of cells in the first passage was a problem. Another one was the increased risk of contamination when higher passages of monolayer cultures were used. For practical purposes it may therefore be more favourable to use second instead of third passage cells.

Animals↗