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Biomedical subjects

B Hansen

Publications and source records attributed to B Hansen.

At least 199 records · Page 11Linked to original sources
PubMed1981

Tyrosine A14[125I]monoiodoinsulin: Preparation, Biologic Properties, and long-term stability.

125I-insulin was prepared by reacting 17.4 nmol porcine insulin (100 micrograms) with 5 mCi 125I (about 2.4 nmol) using the lactoperoxidase method. The reaction product was subjected to gel electrophoresis and the band containing A14 [125I]monoiodoinsulin was eluted. This preparation showed a specific activity of about 1.5 Ci/mumol as evaluated by radioimmunoassay and bioassay, i.e., about 75% of the theoretical maximum. The content of radioactive derivatives other than A14 monoiodoinsulin was less than 2%. The binding affinity of tracer A14 monoiodoinsulin to adipocytes, hepatocytes, and cultured human lymphocytes was twice as high as that of A19 monoiodoinsulin. Binding to antibodies was examined to 10 guinea pig anti-insulin sera. Three sera did not distinguish between the two tracers, whereas seven exhibited higher binding of the A14 tracer. A detailed analysis of one of the discriminating sera showed that the average affinity constant was about 2.5 times lower for the A19 tracer than for the A14 tracer. The A14 monoiodoinsulin tracer is remarkably stable. After 200 days the specific activity had declined to about half of its original value which is consistent with the hypothesis that the physical decay of [125I]monoiodoinsulin (T 1/2 equals 60 days) extinguishes the activity of the molecule without causing major damage of other molecules. By this time 96% of the radioactivity migrated with insulin when subjected to gel filtration on Sephadex G-50, 4% was in the void volume, and nothing in the total column volume or later. Binding to receptors was indistinguishable from that obtained at time zero. It is concluded that Tyr A14[125I]monoiodoinsulin represents an advance in biologic work as compared with previous tracers for insulin.

Adipose Tissue↗
PubMed1981

Binding of C-reactive protein to human lymphocytes. I. Requirement for a binding specificity.

Our laboratory previously reported that C-reactive protein (CRP) binds selectively to T lymphocytes and inhibits certain of their reactivities in vitro. However, these findings could not be repeated using more highly purified CRP preparations even under a variety of experimental conditions. Purified CRP alone did not bind to peripheral blood lymphocytes (PBL); however, in the presence of a ligand such as pneumococcal C-polysaccharide (CPS), CRP binding was readily detectable both by immunofluorescence and by a radioassay established for this purpose. The optimal concentration of CRP, ratio of CRP:CPS, and time and temperature for reactivity were determined using both assays. A markedly enhanced rate of binding was observed after pre-equilibration of CRP with calcium. A small percentage (mean 3.0%; range 0.5 to 8.0%) of PBL bound complexed CRP, and saturation was reached with 200 microgram CRP/ml. Reactivity of CRP with a multimeric form of phosphocholine (PC) (KLH-PC44) led to binding comparable to that observed with CPS, whereas monomeric PC inhibited the binding. Thus, in the presence of a multimeric binding specificity, CRP binds to a small fraction of peripheral blood lymphocytes, which are characterized in the accompanying paper.

Binding Sites↗
PubMed1981

Binding of C-reactive protein to human lymphocytes. II. Interaction with a subset of cells bearing the Fc receptor.

In the preceding paper we reported that C-reactive protein (CRP) in the presence of a multimeric binding specificity such as C-polysaccharide (CPS) binds to a small percentage of peripheral blood lymphocytes (PBL). In the present paper additional methods for demonstrating this binding were developed and utilized to help characterize the CRP-binding cell. Heat-modified CRP and E-CPS-CRP each were found to bind to a similar percentage of PBL by microscopic visualization, and an identical degree of binding was observed by cytofluorimetric analysis. Multiple marker studies indicated that CRP-binding cells are found in the T cell, B cell, and null cell categories in a ratio of 2:1:1, respectively. Preferential overlap was seen with IgG FcR-bearing cells, which accounted for 70% of the CRP-binding cells; however, only 12% of the FcR cells bound CRP. These studies indicate that CRP-binding cells predominantly represent a subset of cells bearing FcR, and these cells have the morphologic characteristics of large granular lymphocytes. CRP in the presence of CPS bound to cells of multiple human and murine cultured lines shown to have IgG FcR reactivity, but showed lesser or no binding to cell lines negative for FcR. The precise morphologic and functional characterization of the CRP-binding cells and the nature of the binding site are yet to be established.

Binding Sites↗
PubMed1981

Agglutination of complement-coated erythrocytes by serum amyloid P-component.

Serum amyloid P-component (SAP) is a normal plasma glycoprotein apparently identical with the P-component associated with amyloid deposits. SAP shows extensive amino acid sequence homology with the C-reactive protein, and both have a similar molecular configuration. SAP undergoes calcium-dependent binding to zymosan, agarose, and amyloid fibrils, but its functional properties are not yet known. We report here that SAP agglutinates complement-(C) coated antibody-sensitized erythrocytes by a calcium-dependent reaction. SAP was found to interact predominantly with a modified form of bound C3b. This modification was achieved by prolonged treatment of EAC43 with heated normal human serum or with isolated C3bINA and beta 1H, and reactivity was reduced upon treatment of the cells with trypsin. SAP thus seems to react with fixed C3 in a manner similar to the reaction of C3 with bovine conglutinin, a molecule that also undergoes calcium-dependent binding to zymosan and agarose. These studies identify a new reactivity for SAP and demonstrate an interaction between an amyloid protein and the C system. The close similarity between the calcium-dependent binding specificities of SAP and of bovine conglutinin may assist in characterization of these molecules and in investigation of their function.

Agglutination↗
PubMed1980

Monoiodoinsulin specifically substituted in Tyr A14 or Tyr A19.

Monoiodoinsulin was prepared using ion exchange chromatography. The isolated monoiodoinsulin showed on polyacrylamide gel electrophoresis two bands with different intensities related to the initial method of iodination. Each of the two bands were isolated from the gel, and determination of the iodine distribution among the tyrosyl groups showed that one band contained monoiodoinsulin substituted in Try A19 contaminated with monoiodoinsulin substituted in the B-chain. The other band contained essentially A14 monoiodoinsulin. Polyacrylamide gel electrophoresis is a convenient method to prepare homogeneous A14 monoiodoinsulin with biological activity indistinguishable from that of native insulin.

Amino Acids↗
PubMed1979

Absorption of protamine-insulin in diabetic patients. I. Preparation and characterization of protamine-125I-insulin.

Protamine-125I-insulin with low specific radioactivity was prepared using 125, 127I-insulin, 0.2 I/mole. The preparations were characterized by disc electrophoresis, isoelectric focusing and analytical gel chromatography in order to evaluate the suitability of 125I-insulin as marker for insulin in protamine-insulin. The stability of the preparations was followed up to 90 days at 4 degrees C. The biological and immunological activity was determined in mice, isolated rat fat cells and by radioimmunoassay. It was concluded that both from a chemical and a biological point of view, the protamine-125I-insulin is a satisfactory preparation that might be used in absorption studies.

Absorption↗
PubMed1979

Chorioretinitis of the newborn with herpes simplex virus type 1. Report of a case.

A disseminated herpes simplex virus (HSV) infection involving the central nervous system and accompanied by chrioretinitis in a a 3-week-old girl is described. The aetiologic diagnosis was established on the basis of vrius isolated from skin vesicles, and a significant rise in complement fixing antibodies to HSV type 1. The mode of transmission of the virus to the infant apparently was direct contact with an oral lesion in the mother, that was present at the time of delivery. The patient survived but became blind and microcephalic, with severe neurological sequelae. The virus isolated was identified as HSV type 1, which is an infrequent finding in herpetic chorioretinitis of the newborn.

Adult↗