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Biomedical subjects

B Nilsson

Publications and source records attributed to B Nilsson.

At least 379 records · Page 21Linked to original sources
PubMed1989

Elevated NK-mediated lysis of Raji and Daudi cells carrying fixed iC3b fragments.

Raji and Daudi cells were opsonized with C3b, iC3b, and C3d fragments by using purified complement components. The sensitivity of C3-opsonized cells to lysis mediated by low density blood lymphocytes was studied. Raji and Daudi cells carrying C3b or C3d fragments were lysed with similar efficiencies as the nonopsonized cells. The presence of iC3b on the target surface imposed elevated NK sensitivity. The iC3b-mediated enhancement of NK lysis was inhibited when iC3b fragments or rabbit anti-human C3 antibodies were included into the lytic assays. These results indicate that the iC3b fragments fixed on the targets bind to the CR3 on the lymphocytes. Results obtained in immobilized conjugate-lytic assays showed that iC3b-opsonized targets interact more readily with the lymphocytes. This was reflected by the elevated proportion of lymphocytes that were bound to the iC3b-carrying targets. The proportions of conjugates in which target damage occurred were similar with the control and with the iC3b-carrying cells. It seems therefore that opsonization of targets with iC3b leads to recruitment of effector lymphocytes due to contact with their CR3. However, once the effector-target contact is established, the triggering of lytic function does not seem to be influenced by the iC3b/CR3 bridge.

Burkitt Lymphoma↗
PubMed1989

Reversed-phase liquid chromatographic determination of idarubicin and its 13-hydroxy metabolite in human plasma.

A method is given for the determination of idarubicin and its main metabolite, idarubicinol, in plasma from cancer patients. Idarubicin and idarubicinol are extracted from 2-ml samples of buffered plasma (pH 8.1) using chloroform-1-heptanol (9:1). After reextraction into phosphoric acid (0.1 M), separation is performed by reversed-phase liquid chromatography on a LiChrosorb RP-2 column (5 microns) with a mobile phase of acetonitrile-water, acidified with phosphoric acid. The absolute recovery in the range 5-100 ng/ml was greater than 83% with a precision better than 8% (relative standard deviation), using photometric detection at 484 nm. Proper handling of whole blood samples containing idarubidin is essential to avoid metabolic conversion into idarubicinol. Prolonged storage of the drug and its main metabolite under alkaline conditions should be avoided to prevent chemical degradation.

Chemical Phenomena↗
PubMed1989

Glycosphingolipids in lectin-resistant variants of mouse Lewis lung carcinoma cells.

Neutral glycolipids and gangliosides from murine Lewis lung carcinoma cell line LL2 and its lectin-resistant variants, differing in metastatic properties, were studied by fast-atom-bombardment mass spectrometry (FAB-MS), exoglycosidase treatment and an immunostaining procedure. The neutral glycolipids identified in all cell lines studied included CMH, CDH, CTH, asialo GM2, globoside and a glycolipid with a preliminary structure of Hex-Hexl-4HexNAc-Hex-Hex-Cer. The major gangliosides were GM3, GM2, GM1 and GD1a. No qualitative differences in glycosphingolipid expression were found between the metastatic cell lines (LL2 and LL2AAA) and the weakly metastatic variants (LL25, LL28, LL230 and LL2RCA II). Some quantitative differences were observed between the cell lines, e.g., in the level of ganglioside-bound sialic acid, which was not apparently correlated with the metastatic capacities.

Animals↗
PubMed1989

Engineering subtilisin BPN' for site-specific proteolysis.

A combination of protein engineering and substrate optimization was used to create variants of the serine protease, subtilisin BPN', which efficiently and specifically cleave a designed target sequence in a fusion protein. The broad substrate specificity of wild-type subtilisin BPN' is greatly restricted by substitution of the catalytic histidine-containing of the catalytic histidine 64 with alanine (H64A) so that certain histidine-containing substrates are preferentially hydrolysed (Carter, P., Wells, J.A. Science 237:394-399, 1987). The catalytic efficiency, (kcat/Km), of this H64A variant was increased almost 20-fold by judicious choice of substrate and by installing three additional mutations which increase the activity of wild-type subtilisin. The most favorable substrate sequence identified was introduced as a linker in a fusion protein between a synthetic IgG binding domain of Staphylococcus aureus protein A and Escherichia coli alkaline phosphatase. The fusion protein (affinity purified on an IgG column) was cleaved by the prototype H64A enzyme and its improved variant, efficiently and exclusively at the target site, to liberate an alkaline phosphatase product of the expected size and N-terminal sequence. Several features of H64A variants of subtilisin make them attractive for site-specific proteolysis of fusion proteins: they have exquisite substrate specificity on the N-terminal side of the cleavage site and yet are broadly specific on the C-terminal side; they can be produced in large quantities and remain highly active even in the presence of detergents, reductants (modest concentrations), protease inhibitors, at high temperatures, or when specifically immobilized on a solid support.

Amino Acid Sequence↗
PubMed1989

Urine-TPA (tissue polypeptide antigen), flow cytometry and cytology as markers for tumor invasiveness in urinary bladder carcinoma.

Urine-Tissue Polypeptide Antigen (U-TPA) was measured in 81 patients with a previously diagnosed bladder carcinoma. U-TPA was elevated in 74% of the patients with invasive bladder cancer as compared to only 15% of the patients with superficial tumors. Only one patient without a tumor recurrence had an elevated U-TPA level (4%). The results were compared with cytological grading and flow-DNA measurements in a multivariate analysis with T-category as the result variable. U-TPA and grade showed each, independently, a significant relation (P much less than 0.001) to T-category whereas the result of the DNA measurements did not explain the variation in T-category when U-TPA and grade were already in the equation. For diagnostic purposes U-TPA seems to be of limited value but may serve as an indicator of tumor recurrence in bladder cancer patients.

Antigens, Neoplasm↗
PubMed1989

Glycosphingolipids of human urothelial cell lines with different grades of transformation.

Neutral glycolipids and gangliosides from seven human urothelial cell lines, differing in grades of transformation (TGr), were characterized by fast atom bombardment mass spectrometry, exoglycosidase treatment and an immunostaining procedure. The major neutral glycolipids identified in all cell lines studied included CMH, CDH, CTH, globoside and paragloboside, the gangliosides were GM3, GM2, sialosylparagloboside and GD1a. The following observations were made: 1. GM2 was the major ganglioside in the TGrII cell lines (non-tumorigenic, non-invasive), but a minor component in the TGrIII cell lines (tumorigenic, invasive). 2. All components showed C16:0 and C24:0 as major fatty acids, but in the TGrIII cell lines the fatty acid composition of CMH and some of the gangliosides were more complex showing unsaturated and hydroxy-fatty acids as well.

Antibodies, Monoclonal↗
PubMed1989

Voluntary relaxation of the external anal sphincter.

In this study five volunteers with special training in anal sphincter exercise (Scandinavian Yoga School) managed voluntarily to reduce anal pressure. The mean reduction of anal pressure was 20 mm Hg. In one of the subjects, this was shown by manometry during low spinal anesthesia and electromyography to be caused by relaxation of the external anal sphincter.

Anal Canal↗
PubMed1989

Structural and immunochemical analysis of three alpha-limit dextrin oligosaccharides.

Complete structures are described for three urinary oligodextrins from one patient with type II and one patient with type III glycogen storage disease. GLC-MS, direct probe MS, and 1H NMR demonstrate two heptasaccharides and one hexasaccharide containing only alpha 1-4 and alpha 1-6 linkages. The observation that all three oligosaccharides were present in urine of both patients and the occurrence of alpha 1-4 and alpha 1-6 linkages in characteristic sequences indicates that the oligodextrins are limit dextrins derived from alpha-amylolytic degradation of glycogen. The binding affinities of the oligodextrins for a monoclonal antibody (401/6) raised against Glc alpha 1-6Glc alpha 1-4Glc alpha 1-4Glc, were determined by frontal analysis. The highest affinity was exhibited by Glc alpha 1-6Glc alpha 1-4Glc alpha 1-4Glc followed by the two heptasaccharides and the hexasaccharide. The results from quantitative affinity measurements agree with results of structural analysis by physical methods in that all oligodextrins containing the nonreducing terminal sequence, Glc alpha 1-6Glc alpha 1-4Glc . . . , are specifically bound by the antibody with similar affinities, but the affinity is somewhat higher for chains containing the tetrasaccharide sequence Glc alpha 1-6Glc alpha 1-4Glc alpha 1-4Glc at the nonreducing terminal. Utilization of affinity methods offers clear advantages for isolation and characterization of oligosaccharides with very similar structures.

Antibodies, Monoclonal↗
PubMed1989

Secretory pattern of growth hormone regulates steroid sulfatase activity in rat liver.

Steroid sulfatase activity was quantified in liver microsomes from hypophysectomized adult female rats treated with estradiol and continuous or intermittent human growth hormone (hGH). Hypophysectomy clearly enhanced sulfatase activity as compared to intact female rats. Normal female values were completely restored by continuous infusion of hGH (1.4 i.u./kg/day). Neither the same dose of hGH given as two daily injections nor estrogen replacement therapy had any effect. It is concluded that liver microsome sulfatase activity in the non-pregnant rat is regulated by the sexually dimorphic secretory pattern of GH.

Animals↗
PubMed1989

Distinctive expression of neoantigenic C3(D) epitopes on bound C3 following activation and binding to different target surfaces in normal and pathological human sera.

Binding of C3 to sheep erythrocytes in a serum-free milieu (EAC14oxy2, EAC142) has previously been shown to mimic the antigenic change that occurs upon denaturation of C3 in sodium dodecyl sulphate (SDS), whereby neoantigenic C3(D) epitopes are exposed. The present paper deals with C3 bound to various target surfaces which are known to modulate the functional properties of C3 in different ways. Bound C3 fragments on serum-treated human aggregated gammaglobulin, zymosan, rabbit and sheep erythrocytes, and on circulating immune complexes isolated from sera of patients with rheumatoid arthritis and systemic lupus erythematosus, were shown to be mainly in the iC3b form. By RIAs, employing polyclonal antibodies, the range of C3(D) antigenic epitopes of 125I-labelled SDS denatured C3 expressed by the particle-bound iC3b was monitored. The physiologically bound iC3b on all tested particles expressed wide range of C3(D) epitopes and each type of particle-bound C3 exposed its individual range. By competition ELISA specific C3(D) alpha epitopes were monitored, employing monoclonal antibodies. A distinct difference in the expression of these epitopes was observed in iC3b bound to various test particles in the presence of normal serum and in iC3b present on circulating immune complexes from pathological sera. Considering that the neoantigenic C3(D) epitopes have been shown to be associated with different functions of C3, the distinctive antigenic expression of each type of serum-treated particle might reflect different functional forms of the protein.

Antibodies, Monoclonal↗
PubMed1989

A method to evaluate the cleaning and disinfectant action of surface disinfectants.

Surface disinfection tests, used to evaluate new disinfectants, do not take into account the effects of detergents or of the mechanical cleaning process. We describe methods which evaluate both the disinfection and cleaning effect of disinfectants on organic matter. When testing alcohols at high concentrations (greater than or equal to 70%) on blood spots contaminated with Staphylococcus aureus, we found that the organisms were trapped and fixed to the test surface, probably due to denaturation of the blood. This gave a low inactivating factor (IF), as well as a poor subjective cleaning effect (SC). If serum was used instead of blood, we observed less pronounced trapping, resulting in a high IF although the SC was still poor. When broth was used, both IF and SC were satisfactory. With alcohols at a concentration of 42%, trapping was markedly reduced which improved the SC in blood contamination, with serum or broth contamination trapping did not occur. However, 42% ethanol lost its killing effect (i.e. low IF), whereas 42% isopropanol still demonstrated a high IF.

Bacteria↗