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Biomedical subjects

A Ljungh

Publications and source records attributed to A Ljungh.

At least 109 records · Page 6Linked to original sources
PubMed1993

A prospective study of first attacks of inflammatory bowel disease and non-relapsing colitis. Microbiologic findings.

In 105 patients with a first attack of colitis, thorough microbiologic investigations of rectal biopsy, faecal, and serum samples were performed with the aims of identifying the colitis-causing agents and shedding light on factors that may precipitate or aggravate the onset of inflammatory bowel disease. Sixty-one patients were found to have inflammatory bowel disease. In 13 (21%) of these patients microbial findings were positive. Eight of the 61 patients fell ill during or immediately after antibiotic treatment, and 10 while travelling abroad. Forty-one of the 105 patients had non-relapsing colitis. In 32 (78%) of these the microbial findings were positive. Six of these 41 patients fell ill during or immediately after antibiotic treatment, and 14 while travelling abroad. Alteration of the intestinal microflora on travelling, gastrointestinal infection, or treatment with antibiotics seems to precipitate or aggravate the symptoms in latent inflammatory bowel disease. In such patients the mode of onset is often changed from insidious to more acute, which may cause difficulty in differentiation from non-relapsing colitis.

Acute Disease↗
PubMed1993

Expression of vitronectin and fibronectin binding by Candida albicans yeast cells.

Expression of binding to vitronectin (Vn or S-protein) and fibronectin (Fn) was common among clinical isolates of Candida albicans. Growth at 37 degrees C enhanced expression of both Vn and Fn binding. Some strains expressed higher binding after growth in liquid media and others after growth on solid media. Most strains expressed higher cell surface hydrophobicity after growth on agar media. Vn binding was less influenced by expression of cell surface hydrophobicity than Fn binding. Vn binding to yeast cells was optimal around pH 4 and Fn binding around pH 6. Binding to soluble Vn was inhibited by unlabelled Vn and to a lesser extent by Fn. Fn binding to the same C. albicans strain was inhibited by unlabelled Fn, Vn, fibrinogen and to some extent collagens. C. albicans strain 3248 expressed specific high binding of Vn, and high binding of Fn. Binding of both proteins was sensitive to heat and protease treatment, but in different ways. Vn binding differed significantly from the earlier reported Fn binding and may represent a novel type of tissue adherence.

Blood Proteins↗
PubMed1993

Bacterial translocation and reticuloendothelial function after implantation of abdominal drainage in the rat.

Bacterial translocation and reticuloendothelial system (RES) function were measured in the rat after intraperitoneal (IP) implantation of rubber drain pieces (7.5 cm2). Six hours after implantation, enteric bacterial translocation was noted to mesenteric lymph nodes (MLNs), the liver, spleen, lungs, kidneys and portal and caval vein blood. RES function was evaluated in terms of blood clearance and organ uptake of intravenously injected 125I-labelled, heat-killed E. coli. A significant elevation of corrected phagocytic index (alpha) was found 24 hours after IP implantation. Localization of 125I-labeled E. coli was significantly enhanced in systemic organs (kidneys, spleen, liver and lungs) 24 hours after IP implantation, whereas it was locally impaired (MLNs and proximal jejunum) 6 hours after IP implantation and thereafter. An inverse correlation between the localization of radiolabelled E. coli in the liver, spleen and lungs and the incidence of bacterial translocation to these organs was found. The results suggest that an association exists between alterations in RES function and bacterial translocation in the early course following IP implantation of rubber drains.

Abdomen↗
PubMed1992

Surface properties, connective tissue protein binding and Shiga-like toxin production of Escherichia coli isolated from patients with ulcerative colitis.

Escherichia coli strains isolated from intestinal biopsies of patients with ulcerative colitis (n 146), Crohn's disease and colonic polyposis (n 41) were analysed for binding of collagen I, collagen IV, fibronectin and laminin. Strains expressed varying degrees of binding of one or more of the four connective tissue proteins. Only 32 strains did not express binding of any of the proteins. The strains expressed low or moderate cell surface hydrophobicity. There was no correlation between protein binding and expression of cell surface hydrophobicity. E. coli isolated from inflamed rectal mucosa were slightly less negatively charged than strains isolated from healthy intestinal mucosa. Shiga-like toxins I and II were detected in 32 strains from 28 patients. Of these, 5 strains had been isolated from normal or healed tissue. In patients with inflammatory bowel disease, connective tissue proteins are exposed in intestinal ulcerations. Strains expressing binding of one or several of these proteins may have a selective advantage to colonize these lesions.

Adolescent↗
PubMed1992

Proposed mechanism for metronidazole resistance in Helicobacter pylori.

Metronidazole MIC values were determined for ten isolates of Helicobacter pylori. Under microaerobic conditions four were inhibited by less than 0.25 mg/L, two strains required 2.0 mg/L and four strains had MIC greater than 32 mg/L. The strains were tested for their susceptibility to metronidazole after varying lengths of anaerobic exposure prior to or during microaerobic incubation. The susceptibility was determined by E-test and traditional agar dilution technique. The level of susceptibility of primarily susceptible strains was not significantly affected by a 2 to 24 h period of anaerobic incubation. However, the effect on resistant strains was dramatic. These strains were increasingly susceptible when a 2 to 12 h period of anaerobicity was provided anytime during the first 48 h and fully susceptible (MIC less than 0.1 mg/L) if 24 h of anaerobicity was provided. When tested again under microaerobic conditions the strains exhibited their original MIC values. The composition of the medium did not influence the results. We propose that "metronidazole resistance" in H. pylori is due to a decreased ability of these strains to achieve a sufficiently low redox potential under microaerobic conditions for the necessary reduction of metronidazole, and that these strains during short periods of anaerobicity manage to reduce and "store" sufficient amounts of metronidazole to appear fully susceptible after subsequent microaerobic incubation. microaerobic incubation.

Anaerobiosis↗
PubMed1992

Ecological effects of short-term ciprofloxacin treatment of travellers' diarrhoea.

Forty-two subjects travelling to Mexico for 11 days were enrolled in a randomized, double-blind, placebo-controlled trial comparing ciprofloxacin 250 mg twice daily for three days or placebo for treatment of travellers' diarrhoea. Seventeen (41%) subjects were randomized to treatment. By the last treatment day, all seven evaluable subjects in the ciprofloxacin group, and three of eight evaluable subjects in the placebo group were cured (P = 0.04). The mean time to cure was 26 h for ciprofloxacin and 60 h for placebo-treated patients (P = 0.03). Faecal specimen were collected pre-travel, after four days in Mexico, 48 h post-travel and four weeks post-travel. Potentially pathogenic Escherichia coli strains carrying diarrhoeagenic virulence genes were detected by DNA hybridization tests, during or after travel, in 41% of treated and 31% of asymptomatic travellers. Travel, irrespective of diarrhoea and type of treatment, had a minor impact on the aerobic and anaerobic microflora. In travellers with ongoing diarrhoea, a suppression of the numbers of anaerobic bacteria was found, but the microflora was otherwise virtually unaffected. Significantly increased frequencies of E. coli resistant to ampicillin, doxycycline, chloramphenicol and co-trimoxazole were found during and after travel in all categories of travellers, though more frequently in subjects who experienced diarrhoea. The susceptibility of Bacteroides spp. remained unchanged. The sensitivity of E. coli to ciprofloxacin was not affected by travel, except in four ciprofloxacin-treated subjects who acquired multiresistant E. coli with ciprofloxacin MICs of > or = 0.125 mg/L post-travel. Bacteroides strains with MICs of > or = 64 mg/L were isolated post-travel from four ciprofloxacin-treated patients, and from one of the other 34 travellers not treated with ciprofloxacin.

Administration, Oral↗
PubMed1992

Characterization of lactoferrin binding by Aeromonas hydrophila.

Various lactoferrin preparations (iron-saturated and iron-depleted human milk lactoferrins and bovine milk and colostrum lactoferrins) were bound by Aeromonas hydrophila. Binding was (i) reversible (65% of bound lactoferrin was displaced by unlabeled lactoferrin), (ii) specific (lactoferrin but not other iron-containing glycoproteins such as ferritin, transferrin, hemoglobin, and myoglobin inhibited binding), and (iii) significantly reduced by pepsin and neuraminidase treatment of the bacteria. The glycosidic domains of the lactoferrin molecule seem to be involved in binding since precursor monosaccharides of the lactoferrin oligosaccharides (mannose, fucose, and galactose) and glycoproteins which have homologous glycosidic moieties similar to those of the lactoferrin oligosaccharides (asialofetuin or fetuin) strongly inhibited lactoferrin binding. A. hydrophila also binds transferrin, ferritin, cytochrome c, hemin, and Congo red. However, binding of these iron-containing compounds seems to involve bacterial surface components different from those required for lactoferrin binding. Expression of lactoferrin binding by A. hydrophila was influenced by culture conditions. In addition, there was an inverse relationship between lactoferrin binding and siderophore production by the bacterium.

Aeromonas hydrophila↗
PubMed1992

Rapid identification of fibronectin, vitronectin, laminin, and collagen cell surface binding proteins on coagulase-negative staphylococci by particle agglutination assays.

Seventeen strains of ten different species of coagulase-negative staphylococci were shown to interact with collagen, laminin, fibronectin, and vitronectin immobilized on latex beads. Different species of coagulase-negative staphylococci have different capacities to agglutinate proteins. Cells of 18 strains of Staphylococcus haemolyticus reacted more strongly than did cells of 18 Staphylococcus epidermidis strains with proteincoated latex beads, although no significant difference in cell surface hydrophobicity or charge could be shown. The cell surface receptors of S. haemolyticus were more heat and protease resistant than were Staphylococcus aureus receptors. Strains of Staphylococcus saprophyticus isolated from urinary tract infections showed a high capacity to adhere to laminin. The ability to agglutinate fibronectin and collagen was common among coagulase-negative staphylococci isolated from other infections; 55% (31 of 56) and 63% (35 of 56) agglutinated fibronectin and/or collagen. S. haemolyticus and S. epidermidis bound to both N-terminal (29-kDa) and C-terminal (120-kDa) fragments of fibronectin.

Bacteriological Techniques↗
PubMed1992

Cell surface proteins of Helicobacter pylori as antigens in an ELISA and a comparison with three commercial ELISA.

Cell surface proteins of Helicobacter pylori were solubilized by extraction with acidic glycine buffer, N-octyl-glucoside, lithium chloride, and distilled water, and by sonication. The preparations were evaluated as antigens in ELISA to detect serum IgG responses in patients and healthy subjects. SDS-PAGE analyses of the preparations from a type strain (NCTC 11637) and of acidic glycine extracts of 4 clinical isolates showed multiple protein bands. The sera were classified as HP+ve and HP-ve by culture of biopsy and immunoblotting. Sera were considered positive for H. pylori if they detected the specific 120kD antigen or 4-5 other bands. 49 sera were HP+ve; the 51 HP-ve sera did not react in immunoblotting. 35/44 sera (80%) that reacted with the 120kD antigen demonstrated high titers in ELISA with all antigen preparations, and the remaining 9(20%) sera gave discordant results. 4/5 HP+ve sera that did not react with the 120kD antigen, demonstrated high ELISA titers with all 5 antigen preparations. Glycine extracts of 3 isolates did not exhibit the 120kD protein, but were equally sensitive in ELISA. The role of 120kD antigen in our ELISA was not clear. Immunoblotting demonstrated that the 5 antigen preparations share similar antigenic components. All preparations were similarly high in sensitivity and specificity, indicating that surface antigens could be satisfactorily used in our ELISA. Our ELISA using the glycine extract was compared with commercial H. pylori ELISAs developed by Bio-Rad Laboratories, USA (GAP ELISA), Roche, Switzerland (EIA 2G), and Whittaker Bioproducts, USA (Pyloristat).(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Bacterial↗
PubMed1992

Haemagglutination patterns of Helicobacter pylori. Frequency of sialic acid-specific and non-sialic acid-specific haemagglutinins.

Thirty-two Helicobacter pylori strains were screened for haemagglutination (HA) activity with erythrocytes of 11 different animal species. Twenty-three strains (72%) that agglutinated human erythrocytes exhibited a broad-spectrum HA profile. Human, guinea pig and bovine erythrocytes high in sialoglycoconjugates were strongly agglutinated by most strains. Except for two, seven strains (22%) that did not agglutinate human erythrocytes exhibited a narrow-spectrum HA profile, commonly not inhibitable by sialoglycoconjugates or N-acetylneuraminlactose (NANLac). Strains were classified into three major HA classes. HA of 10 strains (31%) in class I was inhibited by different combinations of NANLac, orosomucoid or fetuin, but not by asialofetuin, suggesting the presence of sialic acid-specific HAs probably recognizing NeuAc alpha-(2-3)- Gal isomer. Twelve strains (38%) in class II exhibited a different receptor specificity binding to different combinations of NANLac, orosomucoid and fetuin, as well as asialofetuin. No inhibition was observed with 10 strains (31%) in class III; thus, this receptor seems different from both the other classes. Of 21 strains (66%) in classes I and II, HA of 11 strains (34%) was inhibited with NANLac, 14 strains (44%) with orosomucoid and 15 strains (47%) with fetuin. The great heterogeneity observed in HA patterns indicates that the HAs of different strains may recognize a heterogeneous class of sialoglycoconjugates on the erythrocyte membrane.

Animals↗
PubMed1992

Lactoferrin binding properties of Vibrio cholerae.

The lactoferrin binding properties of Vibrio cholerae, a non-invasive pathogen were investigated. Screening of fifty V. cholerae strains of different serogroups and serotypes, showed that 10% of the V. cholerae strains bound to 125I-labelled lactoferrin, and 40% of the 125I-labelled lactoferrin bound to V. cholerae strain 623 could be displaced by unlabelled lactoferrin. Other iron-binding glycoproteins and ferroproteins like ferritin, transferrin, haemoglobin, and myoglobin inhibited the binding of 125I-lactoferrin to a lesser degree. Monosaccharides (GalNac, Man, Gal, and Fuc), and other glycoproteins such as fetuin and orosomucoid also inhibited the binding to a lesser extent. V. cholerae 623 showed a cell surface associated-proteolytic activity which cleaved off the cell-bound 125I-labelled lactoferrin. The generation of cryptotopes on the V. cholerae cell surface by proteolytic digestion favoured the binding of ferritin, transferrin, haemoglobin, and haemin, as well as Congo red, to cells of V. cholerae 623.

Animals↗
PubMed1991

New lectins and other putative adhesins in Aeromonas hydrophila.

The ability of strains of Aeromonas hydrophila to bind 125I-labelled collagen types I and IV, fibronectin, laminin, lactoferrin, and immobilized mucins and orosomucoid on latex beads was found to be a property common to all the isolated strains. The binding was specific, was inhibited by homologous unlabelled glycoproteins, and was protease sensitive. The nature of the binding is discussed.

Aeromonas↗
PubMed1991

Aeromonas and Plesiomonas as food- and waterborne pathogens.

Aeromonas and Plesiomonas have become increasingly recognized as human enteropathogens. Plesiomonas shigelloides has mainly been recovered from various sea foods, whereas Aeromonas sp. have also been cultured from pigs, broilers, eggs, milk and vegetables. Aeromonas sp. also multiply rapidly at +4 degrees C which is a significant risk in food storage. Aeromonas sp. have furthermore been recovered from fresh water sources, and some isolates are resistant to chlorination which makes it a further risk factor. No large food- or waterborne outbreaks have been reported so far with Aeromonas sp. Various virulence factors involved in intestinal infections are described such as enterotoxins, cytotoxins, and adhesins.

Aeromonas↗
PubMed1991

Comparative study of extracellular matrix protein binding to Aeromonas hydrophila isolated from diseased fish and human infection.

Binding of 125I-labelled types I and IV collagen, fibronectin and laminin to Aeromonas cells is a common characteristic among Aeromonas strains isolated from diseased fish and human infections. The proportion of Aeromonas strains which bind to the various proteins were significantly greater for A. hydrophila than for A. sobria or A. caviae. The binding property was specific since it was inhibited by unlabelled homologous proteins. Bacterial cells incubated with proteolytic enzymes lose the ability of binding to 125I-labelled collagen type I and IV, fibronectin, laminin and vitronectin. A bacterial cell surface protein extract, containing active receptors competes with intact cells for 125I-extracellular matrix protein binding. Culture conditions greatly influence the expression of A. hydrophila cell surface binding structures for extracellular matrix proteins. The presence of calcium ions in the growth medium seems to be an important enhancer of the expression of extracellular matrix protein cell surface receptors.

Aeromonas↗
PubMed1990

Fibronectin, vitronectin, and collagen binding to Escherichia coli of intestinal and extraintestinal origin.

Strains of enteropathogenic Escherichia coli (EPEC, 157 strains), enterotoxigenic E. coli (ETEC, 10 strains), enteroinvasive E. coli (EIEC, 40 strains), enterohaemorrhagic E. coli (EHEC, 10 strains), and enteroadherent E. coli (EAEC, 6 strains), all isolated from children and adults with diarrhoea, uropathogenic E. coli (25 strains) and faecal E. coli (36 strains) isolated from healthy persons were tested for binding to subepithelial connective tissue proteins, viz. fibronectin, collagen and vitronectin (S-protein). Strains expressing high and moderate binding to these proteins were found in all groups including normal stools. The highest incidence of binding strains were found among EAEC, EHEC and EPEC strains. Many strains bound collagen only whereas no strain bound vitronectin only. Binding to these proteins was generally best expressed after overnight growth on CFA agar at 37 degrees C. It is not correlated to surface hydrophobicity, and it is not influenced by O antigens or K1 and K5 antigens. The presence of fimbrial adhesins on extraintestinal isolates did not enhance the binding to soluble form of the matrix proteins. During pathological conditions when subepithelial connective tissue proteins are exposed, strains with the ability to bind fibronectin, collagen and/or vitronectin may have a selective advantage to colonize the tissue.

Bacterial Adhesion↗
PubMed1990

Detection of antibodies to Helicobacter pylori cell surface antigens.

Serum IgG antibodies of Helicobacter pylori were detected in single-dilution ELISA using glycine extracted material. Among 148 endoscopy patients 59% displayed antibodies; as expected, a higher occurrence (90%) was found in patients with positive gastric culture for H. pylori than in culture negative patients (37%). Among 68 blood donors the frequency of H. pylori antibodies was 28%. In 73 children less than 15 years of age examined for unrelated disorders the occurrence was 4%. By immunoblotting using the same extract, 3 prominent bands, 29K, 54K and 60K and several weak bands were identified. These were formed by 57%, 92%, and 65%, respectively, of the ELISA positive patient sera. Comparing culture positive and negative patients, the 3 bands occurred more often among the culture positive subjects though between 18 and 61% of the sera from culture negative patients gave either of the bands. When comparing the glycine extracts of 4 different H. pylori strains with separate haemagglutinating patterns no differences in the position of the major bands emerged. By absorption experiments no immunological cross-reactivity with components of Escherichia coli, Klebsiella pneumoniae, Campylobacter jejuni or C. fetus was found. Thus, the glycine extract seemed specific for the detection of antibodies to H. pylori.

Antibodies, Bacterial↗