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Biomedical subjects

K Sveen

Publications and source records attributed to K Sveen.

At least 19 recordsLinked to original sources
PubMed1993

Stimulation of B lymphocytes by lipopolysaccharides from anaerobic bacteria.

Lipopolysaccharides (LPSs) from anaerobic gram-negative bacteria, including those of low endotoxic activity that are isolated from Bacteroides, Prevotella, and Porphyromonas are potent inducers of DNA replication and polyclonal immunoglobulin production in murine B lymphocytes. The activation is dose-dependent and T cell-independent. Replication of DNA and production of immunoglobulins were also stimulated by lipid A and by the LPS heteropolysaccharide that were isolated by mild acid hydrolysis of the LPSs of Bacteroides fragilis and Fusobacterium nucleatum. Combinations of LPS, lipid A, and acid-degraded polysaccharide amplified the blastogenic response. Antibodies that react with the polysaccharide part of LPSs isolated from members of the Bacteroidaceae are present in healthy human serum.

Animals↗
PubMed1992

Comparative mitogenicity and polyclonal B cell activation capacity of eight oral or nonoral bacterial lipopolysaccharides in cultures of spleen cells from athymic (nu/nu-BALB/c) and thymic (BALB/c) mice.

Optimal stimulatory doses of purified phenol-water extracted lipopolysaccharides (LPS) from 5 selected strains of 3 putative periodontopathogens (Fusobacterium nucleatum, Prevotella intermedia, and Veillonella), 3 strains of 2 nonoral bacterial species (Bacteroides fragilis and Salmonella enteritidis), and pokeweed mitogen (PWM) induced significantly higher maximum mitogenic responses and polyclonal Ig production in cultures of unfractionated spleen cells from nu/nu-BALB/c (nude) than from BALB/c (normal) mice. Compared with PWM, the LPS were stronger mitogens showing relative mitogenic capacities: B. fragilis LPS greater than F. nucleatum LPS greater than S. enteritidis LPS, Veillonella LPS, and P. intermedia LPS. B. fragilis LPS was the most and S. enteritidis LPS the least effective polyclonal B cell activator of total Ig, IgG2a, IgG2b, IgG3, IgA, and IgM secretion. IgG1 was not detected. P. intermedia LPS was the strongest IgA inducer. Kinetic observations indicated mitogenic responses and polyclonal B cell activation in a close sequential order in nude and normal cells. The LPS were potent Ag- and T cell-independent polyclonal B cell activators and LPS of subgingival plaque bacteria may therefore play a nonspecific role in the pathogenesis of periodontal diseases.

Animals↗
PubMed1991

Synergistic effect on blastogenesis in murine spleen cells of lipopolysaccharide, lipid A, and acid-degraded polysaccharide from Fusobacterium nucleatum.

Interchangeable combinations of Fusobacterium nucleatum Fev1 lipopolysaccharide (LPS) with its split products by acetic acid hydrolysis, i.e. lipid A (LA) and degraded polysaccharide (PS), amplified the blastogenic response in murine spleen cell cultures as measured by [3H]thymidine uptake. Athymic murine spleen cells precultured with LPS-Fev1 for 48 h (stage 1), washed twice and cultured together with fresh cells and either LA or PS for 72 h (stage 2) gave a synergistic response over that found in spleen cell cultures of thymic mice. Spleen cells pre-cultured with LA or PS and with fresh cells and LPS-Fev1 added to stage 2 cultures gave less significant amplification compared with precultures of LPS and either LA or PS together with fresh cells added to stage 2. Precultures with LA, PS or LPS-Fev1 and with pokeweed mitogen (PWM) and fresh cells added produced an additional increment of synergy which was most pronounced in spleen cell cultures of normal mice.

Acetates↗
PubMed1990

Blastogenesis and polyclonal immunoglobulin synthesis in murine spleen cells stimulated with lipopolysaccharide, lipid A and acid-degraded polysaccharide from Fusobacterium nucleatum.

Lipopolysaccharide of Fusobacterium nucleatum strain Fevl was split by acid hydrolysis. The split products, i.e. lipid A and degraded polysaccharide were mitogenic for murine spleen cells as measured by uptake of [3H]thymidine. The uptake of [3H]thymidine was dose-dependent. Incubation of spleen cells with stimulants for 3 days resulted in a polyclonal activation of immunoglobulin synthesis. Higher mitogenic response and immunoglobulin production were found in spleen cells of athymic mice compared to those of thymic mice. The activity of lipid A in stimulating immunoglobulin synthesis was comparable with the parent lipopolysaccharide-Fevl, the degraded polysaccharide being the less potent stimulator.

Animals↗
PubMed1987

Effect of iopentol on coagulation and platelet function in vitro and in vivo.

The effect on hemostatic parameters of two non-ionic contrast media, iopentol and iohexol in concentrations of 350 mg I/ml, were tested in vitro. The new medium iopentol had similar effects to those of iohexol, both with respect to the intrinsic coagulation system and platelet aggregation. As part of a human pharmacologic study the effects of iopentol on hemostatic parameters were tested in 8 volunteers in vivo. Iopentol induced a slightly decreased coagulability and aggregability in venous blood. It was concluded that the effects were of very little consequence for hemostasis as a whole.

Blood Coagulation↗
PubMed1985

Clearance of Bacteroides fragilis lipopolysaccharide in vivo.

The clearance of bacterial lipopolysaccharide (LPS) from Bacteroides fragilis was studied, using wound chambers implanted subcutaneously in rabbits. The primary skin inflammatory reaction, the Limulus amoebocyte lysate test and the haemagglutination inhibition test all demonstrated a more rapid elimination of LPS from the wound chambers after the second injection, compared to the elimination rate after the first injection given three days earlier. The clearance rate of LPS was significantly higher (0.003 greater than or equal to p greater than or equal to 0.0006) and the number of accumulated leukocytes in the inflammatory exudate significantly lower (p less than or equal to 0.05) after the second injection. Antibodies to B. fragilis LPS in the exudate before the second endotoxin injection was of the 19S IgM class. This suggests that phagocytes in the granulation tissue lining the chamber walls may be of importance in the elimination of endotoxin.

Animals↗
PubMed1985

Intravascular studies with iohexol (Omnipaque). Results from the first 49 clinical trials.

In order to assess the vascular clinical trial program of iohexol (Omnipaque) in Europe, the results from the first 49 vascular trials are collectively reported. The included iohexol material comprises 1742 patients. In 40 comparative trials, other contrast media like metrizamide (Amipaque), ioxaglate (Hexabrix) and various monomeric ionic media were administered in 1292 patients included in this analysis. No severe or unexpected adverse reactions related to iohexol were encountered. No clinically significant differences in radiographic image quality between the media were documented. The overall tolerability of iohexol was superior to that of monomeric ionic media and seemed to be as good as that of metrizamide.

Adolescent↗
PubMed1983

Tolerability of iohexol after injection into healthy volunteers.

The effects of iohexol, a new non-ionic contrast medium, after intravenous injection into humans are reported. After injection of small doses into 2 subjects, iohexol was injected intravenously into 20 healthy male volunteers in doses of 125 to 500 mg I/kg body weight. A large number of physiologic, biochemical, hematologic and pharmacokinetic parameters were analysed. The results indicated that iohexol was well tolerated and that clinical trials in patients could be undertaken.

Adult↗
PubMed1983

Phase II studies in urography, cardioangiography and cerebral angiography with iohexol. An evaluation of the clinical trial program and the clinical findings.

The first experience in patients (phase II studies) with iohexol (Omnipaque) - a new non-ionic contrast medium - in intravenous urography (34 patients), cardioangiography (45 patients) and cerebral angiography (38 patents) is collectively reported. A non-comparative, multicentre design was used in all 3 applications. The objective was to assess the efficacy (the opacity to X-rays) and the tolerability of iohexol using routine contrast medium doses in a well defined adult population. No unexpected or severe reactions occurred in the 117 included or 9 excluded patients. Good efficacy was confirmed, and the contrast medium was well tolerated. The results warrant advancing iohexol into comparative phase III trials. The iohexol phase II studies and initial research in patients with contrast media in general are discussed.

Adolescent↗
PubMed1982

Induction of leukochemotaxis, primary skin inflammation and local Shwartzman reaction by Neisseria gonorrhoeae extract.

The leukochemotactic activity of ultrasonicate of the N. gonorrhoeae strain 8551 was studied by in vitro and in vivo experiments. No chemotactic activity was observed with extract incubated in Gey's solution alone or with heat-inactivated rabbit serum. Activity attracting polymorphonuclear cells was generated on injection of the extract into chambers implanted subcutaneously in rabbits, and in vitro when incubated with fresh rabbit serum, normal guinea pig serum or serum deficient in C4. Chemotactic activity was not observed on incubation with mouse serum deficient in C5. The extract showed pronounced activity in the preparing of rabbits for the local Shwartzman reaction and in inducing primary skin inflammatory reaction. Gonococci this contain chemotaxigens that induce chemotaxin production by means of complement activation via the alternative pathway, and these or other components initiate strong inflammatory responses in vivo.

Animals↗
PubMed1981

Changes of lateral soft tissue profile after surgical correction of mandibular prognathism.

The lateral soft tissue profile was recorded in 10 patients with slight to moderate degrees of mandibular prognathism, preoperatively, and 6 weeks after subcondylar sliding osteotomy had been performed. The recording method was mechanical. Only small and insignificant profile changes were found in the submandibular and occlusal plane regions as well as in the ramus region. The only significant change of profile was found in the mandibular body region, probably as a result of firm connection between soft tissue and underlying distally moved bone. The lack of significant profile change in the osteotomy region was in accordance with subjective observations and was probably due to local remodelling and adaptation processes. The facial width was thus found to be unaltered 6 weeks postoperatively.

Adult↗
PubMed1981

A polypeptide antigen from a strain of Staphylococcus simulans. 2. Antigenic and biological properties.

A purified polypeptide antigen from Staphylococcus simulans CCM 2705 produced one precipitation line by double diffusion in agar with rabbit antiserum against homologous whole bacteria. The purified antigen did not induce antibody production in rabbits. However, when the antigen was complexed with methylated bovine serum albumin, antibodies with specificity against the polypeptide were produced. The antigen did not sensitize normal or tanned erythrocytes for agglutination in antiserum. The polypeptide antigen induced a primary skin reaction and was toxic for mice. It also induced production of MIF as demonstrated by the migration inhibition test. The polypeptide was found to be a leukotaxigen. No difference between C4 normal and C4 deficient serum was noted. C5 was found to be necessary for the induction of chemotaxis.

Animals↗
PubMed1980

Selection of allogenic tooth graft using HLA-A, -B, -C and DR typing and the MLC test.

An allotransplantation of a partly developed premolar from a 12-year-old daughter to her mother is reported. The tooth graft was selected by the use of HLA-A, -B, -C and DR typing and the MLC tests. Follow-up over a 3-year period included periodic identically taken radiographs, electric and galvanic pulp tests and tests for cytotoxic antibodies. Almost complete closure of the apex of the tooth has occurred with no sign of root resorption. The transplant has remained vital, and no production of antibodies against the graft has occurred.

Adult↗
PubMed1980

Bone resorption stimulated by lipopolysaccharides from Bacteroides, Fusobacterium and Veillonella, and by the lipid A and the polysaccharide part of Fusobacterium lipopolysaccharide.

Lipopolysaccharides (LPS) isolated from oral strains of Veillonella, Fusobacterium and Bacteroides stimulated the release of 45Ca from prelabeled fetal rat bones in culture. There was a typical dose-response relationship between the quantities of released 45Ca and LPS used for stimulation. Bacteroides-LPS proved to be the less active inducer of 45Ca release. LPS had no stimulating effect on the release of 45Ca from devitalized bone. The stimulated 45Ca release was paralleled by an increase in the culture medium of hydroxyproline and lactate. This, together with the findings of numerous osteoclasts in stained histological specimens of the experimental bones, indicates that LPS stimulated the osteoclasts to bone resorption. Heparin, which did not directly induce 45Ca release, potentiated the bone resorption stimulating capability of LPS. The lipid A and the polysaccharide portion of Fusobacterium LPS also stimulated bone resorption and, remarkably, the polysaccharide portion showed the greatest activity. This may explain the mode of action of LPS lacking a typical lipid A. It is suggested that stimulation of osteoclasts by LPS may result from activation of complement components by lipid A or its polysaccharide portion.

Animals↗