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T Hofstad

Publications and source records attributed to T Hofstad.

At least 91 records · Page 5Linked to original sources
PubMed1977

Endotoxic activities of lipopolysaccharides of microorganisms isolated from an infected root canal in Macaca cynomolgus.

Lipopolysaccharides (LPS) prepared from a strain of Bacteroides oralis, a strain of Fusobacterium necrophorum, and a strain of F. nucleatum, all isolated from an infected root canal in monkey (Macaca cynomolgus), were examined for endotoxic activities using primary skin reactions in rabbits and induction of leukocyte chemotaxis in rats. LPS of B. oralis showed considerably lower ability to cause skin inflammation than LPS of the fusobacteria. However, the leukotactic effect of the LPS preparations as determined by the wound chamber method in rats was approximately of the same proportion. In both tests the reactions were compared with those of commercial LPS of Salmonella typhi. This study shows that endotoxic LPS can be isolated from oral Gram-negative bacteria, which have infected the root canal. Therefore LPS may play a role in the development and maintenance of chronic inflammation of the periapical tissues.

Animals↗
PubMed1977

Cross-reactivity of Bacteroides fragilis O antigens.

The cross-reactivity of O antigens prepared from Bacteroides fragilis, other Bacteroides species and from Fusobacterium has been examined by indirect haemagglutination and inhibition of haemagglutination. Fifteen of 20 B. fragilis ss. fragilis strains showed O-antigenic cross-reactivity with one or more of the test strains of B. fragilis ss. fragilis: NCTC 9343, Lille E 323 and SBL B55. The same applies also to 3 strains classified as B. coagulans, B. hypermegas and B. putredinis. The multispecificity of B. fragilis O antigens is pronounced. Test systems for demonstration of 9 specificities, all harboured by one or more of the 3 test strains, have been worked out.

Antigens, Bacterial↗
PubMed1977

Chemical composition, serological reactivity and endotoxicity of lipopolysaccharides extracted in different ways from Bacteroides fragilis, Bacteroides melaninogenicus and Bacteroides oralis.

Lipopolysaccharides (LPS) extracted from strains of Bacteroides fragilis, Bacteroides melaninogenicus and Bacteroides oralis with phenol-water, trichloroacetic acid, EDTA or liquid phenol-chloroform-petroleum ether (PCP) and isolated by ultracentrifugation, varied considerably in their quantitative chemical composition. Negligible yields of LPS were obtained by PCP-extraction. All preparations were more or less serologically active. All methods (except PCP) extracted the same O-antigenic determinants from B. fragilis. Endotoxic activity, as measured by primary skin inflammations in rabbits, was low but was present in all preparations. Proteins (and/or lipoproteins) co-precipitated with LPS in the ultracentrifuge.

Bacteroides↗
PubMed1977

Lethality for mice and chick embryos, pyrogenicity in rabbits and ability to gelate lysate from amoebocytes of Limulus polyphemus by lipopolysaccharides from Bacteroides, Fusobacterium and Veillonella.

Phenol-water extracted lipopolysaccharides (LPS) from Veillonella, Fusobacterium nucleatum, Bacteroides fragilis and Bacteroides melaninogenicus were lethal for mice and 11-days-old chick embryos, pyrogenic in rabbits, and gelated Limulus amoebocyte lysate. Mouse lethality was considerably enhanced by actinomycin-D. In all test systems the endotoxin activity of Veillonella and Fusocbacterium LPS was comparable to that of LPS from Salmonella enteritidis, which was included as a reference endotoxin. The endotoxicity of the Bacteroides LPS was very low. While nanograms of the Veillonella and Fusobacterium LPS killed the chick embryos and gelated the Limulus lysates, microgram amounts of the Bacteroides LPS were needed to give positive reaction in the same test systems. As much as 74 microgram of the most active B. fragilis LPS were required to give a typical biphasic fever response in rabbits. A significant correlation was found between all test results (r = 0.90-0.98, p less than 0.001).

Animals↗
PubMed1977

Chemical structure of the lipid A component of lipopolysaccharides from Fusobacterium nucleatum.

The lipid A component of lipopolysaccharides from Fusobacterium nucleatum Fev 1 consists of beta-1',6-linked D-glucosamine disaccharides, which carry two phosphate groups: one in glycosidic and one in ester linkage. The amino groups of the glucosamine disaccharides are substituted by D-3-hydroxyhexadecanoic acid. The hydroxyl groups of the disaccharide backbone are acylated by tetradecanoic, hexadecanoic, and D-3-hydroxytetradecanoic acids. Part of the ester-bound D-3-hydroxytetradecanoic acid is 3-O-substituted by tetradecanoic acid. Whereas a similar pattern of fatty acids was detected in lipopolysaccharides from two other F. nucleatum strains, the amide-bound fatty acid in F. varium and F. mortiferum was D-3-hydroxytetradecanoic acid. The chemical relationships of lipid A from Fusobacteria and other gram-negative bacteria are discussed.

Chemical Phenomena↗
PubMed1977

Stagnant loop syndrome in patients with continent ileostomy (intra-abdominal ileal reservoir).

Intestinal absorption and bacteriology of the ileal contents were compared in seven patients with continent ileostomy and seven patients with conventional ileostomy. The absorption of vitamin B12 was reduced in five patients with continent ileostomy and subnormal in two patients with conventional ileostomy. Steatorrhoea was present in four patients with continent and one patient with conventional ileostomy. Increased concentrations of total anaerobic bacteria and Bacteroides were found in the ileum of the patients with continent ileostomy. After an oral dose of (1-14C) glycocholic acid there was no difference in the faecal excretion of radioactivity, whereas the 14CO2-expiration was increased in two patients with continent ileostomy. In four patients with continent ileostomy and malabsorption of B12, there was evidence of a stagnant loopsyndrome as oral lincomycin treatment resulted in increased absorption of B12 decreased excretion of faecal fat, and decreased concentrations of Bacteroides in the ileum.

Adult↗
PubMed1976

Immunoglobulins in fluid from non-keratinizing jaw cysts.

Thirty-six fluids from non-keratinizing jaw cysts have been examined together with autologous sera by immunoelectrophoresis and double diffusion in agar or agrose gels. Except for one cyst fluid which contained electrophoretically homogeneous ("monoclonal") IgG of the kappa type together with free kappa chains, IgG of cyst fluid was electrophoretically heterogeneous. For the most, IgA of cyst fluid migrated more slowly than IgA of serum, whereas the IgM migrated similarly. The three immunoglobulins showed reactions of antigenic identity with the corresponding Ig classes of serum when examined with rabbit antisera against human IgG, IgA, and IgM. Fluid from the median palatine cyst contained secretory component, which showed a reaction of identity with free secretory component isolated from human saliva, and probably also IgA of the secretory type. Two cyst fluids also precipitated a component in rabbit serum.

Cysts↗
PubMed1976

Purification of the O antigen of Bacteroides fragilis ss. fragilis NCTC 9343 from phenol-water extracts by gel filtration and chromatography on deae-cellulose and hydroxylapatite.

O antigen extracted from whole cells of Bacteroides fragilis ss. fragilis NCTC 9343 with 45 per cent aqueous phenol has been purified by gel filtration and chromatography. First, the water phase was treated with RNase and DNase and passed through a column of agarose. The chromatographic procedures included ion exchange on a column of DEAE-cellulose and adsorption to hydroxylapatite. The O antigen was eluted from the DEAE-cellulose with a gradient of NaCl, and from the column of hydroxylapatite with 1 M phosphate buffer, pH 6.8. Inhibition of indirect haemagglutination was used to detect the O antigen in the eluates.

Antigens, Bacterial↗
PubMed1976

Use of preformed cavities in rabbits for the quantitation of leukocyte chemotaxis caused by bacterial lipopolysaccharides.

Wound chambers implanted subcutaneously in rabbits proved suitable for measurements of leukocyte chemotaxis. Injection of bacterial lipopolysaccharide (LPS) in the chambers the sixth day after implantation was followed by a marked increase of polymorphonuclear leukocytes in the wound chamber fluid, the number of which was dependent on the time after application of LPS. Up to a certain amount of LPS, the concentration of leukocytes in the chamber fluid was dose-dependent. The histopathological appearance of the granulation tissue lining the chamber wall one day after the injection of LPS from Veillonella revealed aggregation of blood cells plugging the lumina of small vessels and many eosinophilic leukocytes.

Animals↗
PubMed1975

Immunochemistry of a cell wall polysaccharide isolated from Eubacterium saburreum, strain L49.

A polymer isolated from E. saburreum strain L49 contained O-acetylated glycero-galacto-heptose as the main constituent, and in addition an unknown aldose. The polymer was located at the outer part of the bacterial cell wall. The polymer reacted with antiserum to L49 microorganisms by precipitation and complement fixation. Two antigenic specificities were detected, one of which was destroyed by de-acetylation. The rabbit antibodies to both specificities were low-molecular-weight antibodies.

Animals↗
PubMed1975

O-antigenic specificity of lipopolysaccharides from Bacteroides fragilis ss. fragilis.

Lipopolysaccharides (LPS) isolated from three strains of Bacteroides fragilis ss. fragilis were examined by indirect haemagglutination and inhibition of haemagglutination in unabsorbed and absorbed rabbit antisera. Six different antigenic specificities were detected. All serological activity was destroyed by oxidation of LPS with periodate.

Animals↗
PubMed1975

The uptake of vitamin B12 by the sediment of jejunal contents in patients with the blind-loop syndrome.

Following preincubation of intrinsic factor- (IF-) bound 57CoB12 with the jejunal sediments of 6 patients with the blind-loop syndrome, the mean uptake by the sediments of IF-57CoB12 (28.1 percent plus or minus 4.2 percent S,E.M.) was significantly higher than the mean uptake by jejunal sediments from 5 control patients (5.8 per cent plus or minus 3.5 percent) (p smaller than 0.01). The uptake by the sediments significantly decreased when the incubations were carried out in the presence of lincomycin and neomycin. The jejunal sediments from the patients with the blind-loop syndrome inhibited the uptake of IF-57CoB12 by perfused rat intestinal segments (p smaller than 0.01), whereas the sediments from the control patients had no such inhibitory effect (p smaller than 0.5).

Aged↗