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Biomedical subjects

B Nilsson

Publications and source records attributed to B Nilsson.

At least 451 records · Page 25Linked to original sources
PubMed1987

The effect of low molecular weight heparin on experimental thrombosis and haemostasis--the influence of production method.

Three low molecular weight heparins prepared by enzymatic depolymerization, chemical degradation, and fractionation, respectively were studied in experimental thrombosis and haemostasis models in vivo and in biological assays in vitro. The three low molecular weight heparins, which had comparable molecular weight distributions, showed very similar activities both in vitro and in vivo. All three showed dose dependent thromboprophylactic effect. The antithrombotic effects of the low molecular weight heparins and conventional heparin administered in the same dose (30 XaI u/kg b.w.) did not differ. Neither LMW heparin nor conventional heparin (60 or 90 XaI u/kg b.w.) showed significant effects on the haemostatic plug formation time in the rabbit mesenteric microcirculation. These experiments confirm that low molecular weight heparins are potential antithrombotic drugs, which by intravenous administration have effects similar to those of standard heparin. The method of preparation seems to be of no or minor importance, at least if the molecular weight distributions of the products are similar.

Animals↗
PubMed1987

Anti-idiotypic antibodies in antisera against human C3 and factor H and their application in the enrichment of antibodies specific for H-binding domains of C3.

Antisera separately raised against C3 and factor H should contain antibodies against the binding domains by which these factors interact. Because these interacting domains are likely to be sterically complementary to each other, antibodies specific for these domains should also be sterically complementary or of anti-idiotypic specificity. To test this hypothesis, rabbit anti-human C3 IgG antibodies which bound to Sepharose-coupled rabbit anti-factor H IgG (anti-H-binding anti-C3) were separated by affinity chromatography. In a control experiment, the anti-human factor H column was found to bind 10 times more anti-C3 antibodies than a Sepharose column coupled with nonimmune rabbit IgG. The binding specificity of the control eluate was indistinguishable from the original anti-C3 preparation, whereas the anti-H-binding anti-C3 was shown to be enriched in regard to antibodies directed against the 42 kd fragment of the C3 alpha-chain of C3c, as demonstrated by immunoblotting of electrophoretically separated polypeptides of C3c and C3d in polyacrylamide gels. In competition binding studies, factor H was 25 times more potent as inhibitor of the anti-H-binding anti-C3 than of the original anti-C3 preparation. This similarity in binding specificity also paralleled a functional similarity in that anti-H-binding anti-C3 in the presence of factor I effected a 20% degradation of the alpha'-chain of C3b into fragments of 65, 45, and 42 kd which are the normal degradation products in the presence of factors I and H. These results suggest that the affinity procedure described resulted in the enrichment of anti-C3 antibodies with selective specificities for factor H-binding domains of C3, from a polyclonal antibody source.

Antibody Specificity↗
PubMed1987

Alternative pathway of complement activation by stimulated T lymphocytes. II. Elevation of cytotoxic potential against complement receptor-carrying cell lines.

Exposure of lectin-stimulated (concanavalin A, phytohemagglutinin and pokeweed mitogen) blood lymphocytes to human serum or to purified C3 increased their cytotoxic capacity towards complement receptor positive targets such as Raji and Daudi cells. The lysis of complement receptor-negative lymphoblastoid cell lines was not influenced. The lytic capacity of lymphocytes exposed to 12-O-tetradecanoylphorbol 13-acetate was not elevated by human serum. Lectin-stimulated lymphocytes were previously shown to activate and bind C3. The results using lymphocytes activated in different ways and targets with or without complement receptor expression suggest that the C3b deposited on lymphocytes binds to the complement receptor on the targets. This contact elevates the avidity between the two cells as indicated also by the increased frequency of the lymphocyte-target conjugates. On the basis of immune adherence the C3 fragment bound on the lymphocytes was identified as C3b. The increase of the conjugate formation and cytotoxicity was abrogated when the target cells, Raji, were pre-exposed to purified C3d which occupy the CR2 receptor. The majority of lymphocytes responsible for the cytotoxicity were CD8+.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1987

Cloning and expression of the gene for a fibronectin-binding protein from Staphylococcus aureus.

The gene encoding the fibronectin-binding protein (FNBP) from Staphylococcus aureus strain 8325-4 was isolated from a gene bank in pBR322. The original clone, containing a 6.5-kb insert, gave a functional product present in the periplasm of Escherichia coli. Analysis of polypeptides isolated after affinity chromatography on fibronectin-Sepharose followed by ion-exchange chromatography revealed two gene products, 87 and 165 kd in mol. wt. The amino acid compositions of these two polypeptides and a native FNBP from S. aureus strain Newman were very similar. Antibodies raised against the native FNBP from strain Newman precipitated the 125I-labelled 165-kd polypeptide, and unlabeled 165- and 87-kd polypeptides as well as native FNBP inhibited the immunoprecipitation reactions. The region of the fnbp-gene encoding the fibronectin-binding activity has been identified and subcloned in an expression vector based on the staphylococcal protein A gene. The resulting product in E. coli is an extracellular fusion protein consisting of two IgG-binding domains of protein A followed by a fibronectin-binding region. The fusion protein binds to fibronectin and completely inhibits the binding of fibronectin to intact cells of S. aureus.

Cloning, Molecular↗
PubMed1987

Quantitation and antigenic characterization of bound C3 of circulating immune complexes in systemic lupus erythematosus, rheumatoid arthritis, and primary biliary cirrhosis.

In recent years defective function of the complement-mediated clearance of immune complexes (IC) has been reported in patients with immune complex disease. The defect has been found at different levels in the clearance system. An important event in this sequential system is the binding of C3-coated particles to C3 receptors on erythrocytes and phagocytes. This study focuses on immunochemical properties of IC-bound C3 that reflect the functional state of the molecule. Sera from patients with primary biliary cirrhosis (PBC), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE) and from normal subjects were analyzed for their level of C3 precipitable in 2.7% (w/v) polyethylene glycol (PEG). The mean levels for the patient categories were significantly higher than that for the normal subjects. The immunochemical study revealed several differences among the different forms of PEG-precipitable C3. All forms expressed C3(D) antigens which are expressed by immune complex-associated and denatured forms but not by soluble physiological forms of C3. The expression of these antigens was proportionately lower for the complex-associated C3 of PBC compared to that of RA and SLE. Furthermore, employing monoclonal anti-C3(D) antibodies against the C3c and the C3d domain, distinct differences could be detected among all forms of PEG-precipitable C3. Sera from RA and SLE, in particular, contained PEG-precipitable C3 that exhibited distinctive immunochemical features with respect to these epitopes.

Antibodies↗
PubMed1987

Production of mouse monoclonal antibodies that detect distinct neoantigenic epitopes on bound C3b and iC3b but not on the corresponding soluble fragments.

Polyclonal antibodies raised in rabbits against sodium dodecyl sulphate (SDS)-denatured and reduced human complement factor C3 have in recent studies been shown to lack any reactivity towards native C3 but to react with antigens distinctly expressed by SDS-denatured C3 (C3(D) antigens). These antigens are also neoantigens specific for physiologically bound C3 and appear to be involved in the interaction of C3 with other complement components. The present investigation deals with production of mouse monoclonal antibodies against C3(D) antigens. To accomplish this two different immunization and screening procedures employing C3 preparations of known C3(D) expression were tested. From each group 14 clones were randomly selected and the reactivity of these and of a control group of 14 additional monoclonal anti-human C3 antibody preparations raised against native soluble C3 and C3b, was investigated in ELISA and immunoblotting. The procedure which employed denatured reduced C3 as both immunogen as well as screening antigen was shown to be superior for obtaining anti-C3(D) antibodies. Altogether 16 clones producing antibodies against C3(D) antigens were found. All of them bound to the C3 alpha-chain, 14 to C3c and one to C3d, and eight monoclonal antibodies specific for neoantigens of C3(D) type on bound C3b and/or iC3b were obtained. The majority of these detected neoantigenic epitopes in the 25,000 N-terminal fragment of the C3 alpha-chain specifically exposed by bound iC3b, but one monoclonal antibody was specific for the 36,000 C-terminal alpha-chain fragment and for both bound C3b and iC3b.

Animals↗
PubMed1987

Blood clonal B cell excess (CBE) at diagnosis in patients with non-Hodgkin lymphoma (NHL). Relation to clinical stage, histopathology and response to treatment.

Untreated non-leukemic (lymphocytes less than or equal to 4.0 X 10(9)/l) patients with non-Hodgkin lymphoma (NHL) of B cell type often show an excess of B cells in peripheral blood bearing the same light chain isotype as the lymph node tumor cells which may indicate a leukemic spread of the disease. The ratio between kappa- and lambda-bearing lymphocytes (normal range 1.0-3.3) was studied to evaluate the prognostic significance of clonal B cell excess (CBE) at diagnosis in 110 NHL patients. In total 43% had a CBE in peripheral blood. Fifty-two per cent of the patients in clinically advanced stages had CBE and 30% of the patients in stages I and II. CBE was detected in 49% of all patients with low-grade malignant lymphoma and in 32% with high-grade malignancy. Patients with a normal kappa:lambda ratio at diagnosis entered complete remission more often than those with CBE (P less than 0.01). In patients with high-grade but not with low-grade malignant lymphomas remission duration was longer for those with normal kappa:lambda distribution than for the patients with an abnormal ratio (P less than 0.01). Survival was not statistically significantly influenced.

Adult↗
PubMed1987

A gene fusion system for generating antibodies against short peptides.

A novel method to obtain specific antibodies against short peptides is described, involving synthesis of the corresponding oligodeoxynucleotides followed by cloning into a new set of fusion vectors, pEZZ8 and pEZZ18, based on two synthetic IgG-binding domains (ZZ) of Staphylococcus aureus protein A. The soluble gene fusion product thus obtained, can be collected from the culture medium of Escherichia coli and rapidly recovered in a one-step procedure by IgG affinity chromatography. The system was used to express a fusion protein consisting of the two Z fragments and the C-terminal part [amino acids (aa) 57-70] of human insulin-like growth factor I (IGF-I). This 16-kDa protein was purified by affinity chromatography on IgG Sepharose and antibodies were raised in rabbits. The fusion protein elicited peptide-specific antibodies, as measured by solid-phase radioimmuno assay and Western blotting, reactive with both synthetic C-terminal peptide and the native human IGF-I protein. The results suggests that the gene fusion system can be used for efficient antibody production against short peptides encoded by synthetic oligodeoxynucleotides.

Amino Acid Sequence↗
PubMed1987

Production and detection of coliphage T4 endonuclease V polyclonal and monoclonal antibodies using staphylococcal protein-A hybrid proteins.

To facilitate the production of antibodies against endonuclease V, a pyrimidine dimer-specific DNA glycosylase produced in bacteriophage T4-infected Escherichia coli, we constructed plasmids containing protein-A-endonuclease V fusion genes under control of the E. coli tac promoter. Induction with isopropyl-beta-D-thiogalactopyranoside produced large amounts of fusion proteins, which could easily be purified on human IgG agarose columns. The affinity-purified fusion proteins were injected into rabbits and mice to produce polyclonal and monoclonal antibodies, and also used for the screening of the monoclonal antibodies. These antibodies recognized endonuclease V on immunoblots, and also inhibited the DNA-glycosylase activity in vitro. Epitope mapping of monoclonal antibodies showed that they all (6/6) recognized determinants in the C-half of endonuclease V. A convenient way to detect primary antibodies on nitrocellulose was also developed using a crude protein extract containing protein-A-beta-galactosidase fusion protein and subsequent detection with a mixture of dyes.

Antibodies, Monoclonal↗
PubMed1987

Variables predicting bacterial and fungal infections after allogeneic marrow engraftment.

Sixty-seven consecutive patients with aplastic anemia or leukemia who had been treated by allogeneic marrow transplantation and had survived for more than 1 month were surveyed in order to determine the incidence of nonviral infections occurring from 1 month to 3 years after transplantation. Twenty-eight of the 67 patients had one or more infections during this period. Around 20% suffered from pulmonary infections and 20% were classified as having a systemic infection. Ten patients died of bacterial or fungal infection, of whom 6 had graft-versus-host disease. In multivariate analyses acute graft-versus-host disease (P less than 0.0009), splenectomy (P less than 0.02), cytomegalovirus infection (P less than 0.05), and a low marrow cell dose (P less than 0.07) were correlated with nonviral infections.

Adolescent↗
PubMed1987

Blood clonal B cell excess at diagnosis in multiple myeloma: relation to prognosis.

112 patients with multiple myeloma have been studied at diagnosis for the presence of blood clonal B-cell excess (CBE), defined as a ratio between kappa+ and lambda+ lymphocytes outside the normal range (0.9-3.5). 48 patients (43%) had CBE. The increase in light chain-bearing lymphocytes was always that of the M component light chain isotype. The proportions of patients exhibiting CBE were the same in different stages. The response frequency was not influenced by the presence of CBE. However, patients with CBE had a shorter remission duration time (p less than 0.001) and total survival (p less than 0.05) than those without CBE. This was also noticed when each clinical stage was analyzed separately. Moreover, survival was shorter in patients with a large fraction of CBE than in those with a small one. Cox regression analysis revealed that CBE was a much stronger predictor of remission duration than age, clinical stage and renal dysfunction. CBE and response to initial treatment independently were the best factors to indicate survival. It is suggested that analysis of CBE should be included in the clinical characterization of untreated patients with multiple myeloma.

Adult↗
PubMed1987

T lymphocyte subpopulations in chronic lymphocytic leukemia of B cell type in relation to immunoglobulin isotype(s) on the leukemic clone and to clinical features.

Total blood T lymphocytes and subpopulations (OKT4+ and OKT8+ cells) were studied in 59 patients with B cell chronic lymphocytic leukemia (B-CLL). In 48 previously untreated patients, total T lymphocytes were higher as compared to healthy controls (p less than 0.001). T-cells and OKT8+ cells were significantly increased in patients in advanced clinical stage and with progressive disease in comparison to patients with low stage and indolent disease. High numbers of OKT8+ lymphocytes were also seen in patients with a dominance of mu heavy chains on the leukemic clone. Moreover, in this patient group the OKT8+ subpopulation correlated with total B cells (r = 0.68, p less than 0.001) while in patients with a mu delta phenotype no such correlation was seen. After successful cytostatic therapy there was a reduction in total numbers of both OKT4+ and OKT8+ cells, in particular, with a concomitant increase in OKT4/OKT8 ratios.

Adult↗
PubMed1987

Receptor-specific agglutination tests for detection of bacteria that bind globoseries glycolipids.

Specific binding to the globoseries of glycolipid receptors explains the adherence of uropathogenic Escherichia coli to host cells. The minimal receptor disaccharide Gal alpha 1----4Gal beta [galactose alpha (1----4)galactose beta] is recognized by most attaching clinical isolates. However, wild-type isolates can express adhesins with several different receptor specificities. Bioassays do not permit separate analysis of each receptor specificity, since the target cells contain multiple potentially receptor-active molecules. In this study, bacterial adhesins were analyzed by using receptors immobilized into latex beads in one of two ways. In one way, di- and trisaccharides were covalently linked via a spacer arm to latex beads coupled with bovine serum albumin. In the other way, receptor-active glycolipids were coated onto the bovine serum albumin-latex beads. The latex beads were subsequently used for agglutination by using type strains with known receptor specificity. The composition was optimized regarding receptor structure and size of latex beads. Gal alpha 1----4Gal beta was as active as the trisaccharide derivative Gal alpha 1----4Gal beta 1----3glucose or Gal alpha 1----4Gal beta 1----3glucosamine. Among the natural glycolipids tested, globotetraosylceramide was the most active. Subsequently, the sensitivity and specificity of the Gal alpha 1----4Gal beta-latex and globotetraosylceramide-latex reagents were compared for 733 E. coli urinary isolates. Hemagglutination of human erythrocytes was used as the positive standard. No significant difference in the specificity or sensitivity of the latex reagents was found; the sensitivity ranged from 86%, when isolates agglutinating human erythrocytes of blood groups P1 and p were included, to 93%, when those isolates agglutinating erythrocytes of blood group p were excluded. These reagents provide tools for bacterial identification in patients with urinary tract infection.

Adhesins, Escherichia coli↗
PubMed1987

Binding to galactose alpha 1----4galactose beta-containing receptors as potential diagnostic tool in urinary tract infection.

The diagnosis of urinary tract infection is based largely on quantitative urine cultures. The usefulness of qualitative information about the virulence of the infecting bacteria remains undefined. Ability to attach to human uroepithelial cells is one characteristic of the pyelonephritogenic clones, as well as a virulence factor per se. The identification of host cell receptors for attaching bacteria has permitted the construction of agglutination tests for simple detection of bacterial binding properties. In the present study, the reactivity with Gal alpha 1----4Gal beta-latex [galactose alpha (1----4)galactose beta-latex] and globotetraosylceramide-latex was analyzed for strains from patients with acute pyelonephritis (n = 135), acute cystitis (n = 121), and asymptomatic bacteriuria (n = 119) and from the fecal flora of healthy children (n = 120) and compared with agglutination of human blood group P1 and p, as well as guinea pig, erythrocytes. The reactivity by bioassay and the receptor-specific assays were significantly correlated. The frequency of positive reactions among the pyelonephritis isolates was 78.5% with the globotetraosylceramide-latex reagent, compared with 41% for the cystitis isolates, 25% for the asymptomatic bacteriuria isolates, and 13% for the fecal isolates. The combination of bioassays and receptor-specific assays increased the resolution of adhesins. Thus, adhesins reacting with human p erythrocytes frequently were coexpressed with Gal alpha 1----4Gal beta-specific adhesins. The receptor-specific assays provide a refined reagent to resolve bacterial binding specificities, as well as a potential tool for clinical diagnosis.

Adhesins, Escherichia coli↗
PubMed1987

Acute thrombogenicity of a compliant polyurethane urea graft compared with polytetrafluoroethylene: an experimental study in sheep.

The acute thrombogenicity of a new polyurethane urea graft has been compared with polytetrafluoroethylene (PTFE) grafts using labelled homologous platelets in the carotid arteries of sheep in a low-flow model. There was no difference in patency. Thrombus weight and thrombus free surface were the same in both types of graft after 4 h. The accumulation of homologous 32P platelets was measured at the 2 anastomoses and at a midgraft position. At no point was there any statistically significant difference between the 2 grafts, but the activity was always somewhat higher in the polyurethane grafts. Although more compliant, in this study polyurethane urea grafts behaved much like PTFE ones.

Animals↗
PubMed1987

Treatment of invasive grade 3 transitional cell bladder cancer. A retrospective study of 10 years' experience with external irradiation, and preoperative irradiation and cystectomy.

Three hundred and seventy-four patients with invasive grade 3 bladder cancer treated with either external irradiation or preoperative irradiation and cystectomy were re-evaluated. Cancer-free survival was markedly better for patients who underwent preoperative irradiation and operation than irradiation only, even if a complete clinical response had occurred initially.

Aged↗
PubMed1987

Incidence of infectious symptoms after radiation therapy for breast cancer. Long-term effects.

The incidence of symptoms generally associated with infectious disease was assessed by a questionnaire sent out to 519 disease-free breast cancer patients 7 to 12 years after primary treatment. All patients were treated in the context of a randomized trial where pre- and postoperative radiation (45 Gy) was evaluated versus surgery only. The results indicate a significantly higher morbidity among patients treated with preoperative irradiation compared with those irradiated postoperative (p less than 0.05). This increased morbidity mainly seemed to be caused by symptoms usually associated with respiratory tract infection (p less than 0.05). Although statistically not significant the preoperatively irradiated patients also had a higher morbidity than those treated with surgery alone. There was no difference between postoperatively irradiated patients and patients treated with surgery only. A significantly higher integral dose (absorbed energy within the body) of the pre- compared with the postoperative group (p less than 0.025) is associated with the differences in morbidity between the two irradiated groups. An explanation for the increased morbidity seems to be that the volume of lung tissue, encompassed within the full-dose target volume, is the crucial factor. This volume was considerable in the preoperatively treated patients but kept at a minimum in the postoperative group.

Adult↗