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A Forsgren

Publications and source records attributed to A Forsgren.

At least 37 records · Page 2Linked to original sources
PubMed1997

Association between Helicobacter pylori and gastric carcinoma in the city of Malmö, Sweden. A prospective study.

BACKGROUND: We have investigated the association between Helicobacter pylori and gastric carcinoma through a nested case-control study in a single city. METHODS: From a cohort of 32,906 residents recruited from 1974 through 1992, 56 cases of gastric adenocarcinoma and 224 matched controls were selected. The mean interval between serum collection and diagnosis was 5.7 years. Frozen serum or plasma samples were analysed for IgG antibodies against H. pylori with an enzyme-linked immunosorbent assay. RESULTS: The overall seropositivity prevalence in gastric cancer cases was 82%, compared with 49% in controls, giving an odds ratio (OR) of 5.0 (95% confidence interval (CI), 2.2-11.5). Partial gastrectomy because of peptic ulcer 5 to 36 year before diagnosis of gastric cancer could be a confounding factor. With exclusion of 10 such cases, H. pylori seropositivity among cases was 78%, as compared with 50% in matched controls (OR, 3.9; 95% CI, 1.7-9.2). Tumours of the cardia were not associated with H. pylori (OR, 0.92; 95% CI, 0.23-3.7), which is in contrast to tumours of the fundus, corpus, and antrum, which were significantly associated (OR, 11.1; 95% CI, 2.4-71.8). This difference in location was significant (P < 0.01). CONCLUSION: There is a significant association between prior infection with H. pylori and later development of gastric carcinoma, and the association is related to noncardia gastric cancer.

Adenocarcinoma↗
PubMed1997

Antimicrobial susceptibility testing in Sweden. I. The work of the Swedish Reference Group for Antibiotics (SRGA and SRGA-M).

The Swedish Reference Group for Antibiotics (SRGA) is an expert committee within the Swedish Medical Society and has been working with different aspects of susceptibility testing of bacteria to antibiotics since 1978. The emphasis has been on standardization of methodology, evaluation of the in vitro activity of new and old antibiotics, and the detection and significance of resistance mechanisms in bacteria. In the following a review is presented of the work conducted by the SRGA.

Anti-Bacterial Agents↗
PubMed1996

Effect of Haemophilus influenzae type b conjugate vaccine in combination with peroral immunization with Escherichia coli on experimental otitis media.

The protective ability of a conjugated Haemophilus influenzae type b vaccine, ACT-HIB, used singly or in combination with orally administered Escherichia coli, was investigated in a rat model for acute otitis media. The humoral response to ACT-HIB was also analyzed. The study demonstrated that ACT-HIB vaccination resulted in a prompt antibody response, and that ACT-HIB was efficient in preventing middle ear infections caused by Haemophilus influenzae type b. The efficiency increased if the vaccine was combined with Escherichia coli. The results suggest that Escherichia coli could possibly be useful in the future as a vaccine vehicle, and since Haemophilus influenzae acute mastoiditis seems to be almost exclusively due to serotype b, the incidence of this infection may be reduced with the conjugated Haemophilus influenzae type b vaccines.

Acute Disease↗
PubMed1996

Laminin binding to a heat-modifiable outer membrane protein of Actinobacillus actinomycetemcomitans.

The interaction of Actinoabacillus actinomycetemcomitans with the basement membrane protein, laminin, was examined in a 125I-labeled protein-binding assay. The binding of laminin increased by lowering the pH. The ability to bind laminin was decreased in cells at the stationary phase of growth and by the presence of blood in the culture medium. Laminin binding to this bacterium was saturable, and the affinity constant was 4.6 nM. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis and Western blot (ligand blot) analysis of cell-envelope and outer membrane of A. actinomycetemcomitans displayed a 125I-laminin-reactive protein band with a molecular weight of 29 k. The laminin-binding protein was the previously described outer membrane protein A of A. actinomycetemcomitans. It was identified by its heat-modifiable property, detergent-solubility profile and reactivity with outer membrane protein A-specific polyclonal antiserum. At acidic pH, 25I laminin bound to several cell-envelope components of A. actinomycetemcomitans, but at neutral pH, laminin bound only to the heat-modifiable protein. Despite the existence of the laminin-binding protein, cells grown in blood-containing media did not bind laminin. Several mammalian proteins interfered with laminin-bacterial interaction, including lactoferrin, which binds to the same bacterial protein that inhibited and displaced the laminin-bacterial interaction.

Aggregatibacter actinomycetemcomitans↗
PubMed1996

Biological activity of serum antibodies to a nonacylated form of lipoprotein D of Haemophilus influenzae.

Protein D, a surface-exposed 42-kDa membrane lipoprotein, is well conserved among both type b and nontypeable Haemophilus influenzae strains, and it is considered a vaccine against H. influenzae infections. Here, we report the large-scale purification of a nonacylated form of protein D (PDm) from the periplasmic space of Escherichia coli overexpressing PDm. Screening of human sera for levels of antibodies to PDm demonstrated that the immunoglobulin G (IgG) antibody level is above background levels in infants less than 6 months of age. Following a drop to background values in the age group 6 months to 1 year, IgG antibody levels start to increase, together with IgA antibody levels, after 1 year of age. The first appearance of serum IgM antibodies is in 6-month- to 1-year-old infants whose IgG antibody levels have dropped to the postnatal background level. Affinity-purified antibodies from humans and from PDm-immunized rats detected epitopes of protein D which are normally exposed on the bacterial surface. Affinity-isolated human anti-PDm antibodies eluted in acidic buffer were not bactericidal against H. influenzae. Loss of bactericidal activity may occur in this buffer, as was demonstrated in pooled human sera with high bactericidal activity after incubation in the same buffer. Hyperimmunization of rats with PDm induced high levels of serum IgG and IgA antibodies against PDm and significant bactericidal activity against homologous and heterologous H. influenzae strains.

Acylation↗
PubMed1996

Local and systemic antibody levels against protein D of Haemophilus influenzae following immunization and infection in rats.

Outer membrane proteins of Haemophilus influenzae are considered as possible vaccine candidates against non-typable H. influenzae (NTHi), a major cause of respiratory infections. Here, we study local and systemic antibody responses to protein D, a well-conserved 42-kDa membrane protein, following local and systemic immunization, and experimental acute otitis media (AOM) with NTHi and H. influenzae type b (Hib) in rats. Animals that were challenged and rechallenged in the middle ear with Hib strain Minn A or NTHi strain 1161 developed IgG and IgA antibodies in serum but not in middle ear lavage (MEL) material or saliva. In contrast, following per oral immunization with NTHi strain 772 and Escherichia coli JM83 (pHIC348) (containing protein D gene) and, to a lesser degree after intranasal inoculation of NTHi strain 772, high saliva IgA antibodies to protein D developed, but there was no rise in antibodies to protein D in the MEL material or the sera of these animals. These results show that protein D can elicit different systemic and local antibody responses depending on the site of delivery and the form of administration. Furthermore, experimental AOM with NTHi and Hib induces systemic IgG and IgA antibodies to protein D but fails to induce a mucosal immune response.

Animals↗
PubMed1995

Enhancement of the immunosuppressive effect of cyclosporin A by ciprofloxacin in a rat cardiac allograft transplantation model.

Ciprofloxacin hyperinduces interleukin-2 production in stimulated human and mouse lymphocytes. In this study, an enhanced and prolonged interleukin-2 response was also detected in polyclonally stimulated rat splenocytes in the presence of ciprofloxacin (5-80 micrograms/ml) compared to control cells without any antibiotic. Ciprofloxacin was able to counteract the immunosuppressive effect of 10 ng/ml cyclosporin A (CyA) but did not interfere with higher CyA concentrations. In parallel, ciprofloxacin did not influence thymidine uptake in mixed lymphocyte reactions in the presence of CyA. To obtain an in vivo application of these findings, graft survival was studied by performing rat cardiac allograft transplantations in the presence or absence of CyA. Brown Norway rats served as donors and Wistar Furth rats as recipients. Ciprofloxacin was injected intraperitoneally either at a high-dose regimen (240 mg/kg per 24 h) into rats every 8th h starting 1 day before transplantation until day 21 or graft loss, or it was injected at a low and clinically relevant dose regimen (45 mg/kg per 24 h) until day 9. CyA was administered orally (10 mg/kg per 24 h) from day 1 through day 9. Ciprofloxacin given alone at a high-dose regimen resulted in a median graft survival of 14.8 days, which was significantly longer than graft survival in rats without treatment (median 8.0 days). A low-dose regimen of ciprofloxacin alone did not affect graft survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

CP-115,953 stimulates cytokine production by lymphocytes.

The cytotoxic quinolone CP-115,953 specifically exerts its inhibitory effect upon eukaryotic topoisomerase II. CP-115,953 stimulates DNA cleavage mediated by topoisomerase II with a potency approximately 600 times greater than that of ciprofloxacin, a quinolone antibacterial agent that currently is in clinical use. Because ciprofloxacin has been reported to strongly enhance interleukin-2 production, we considered it important to study the effect of CP-115,953 on interleukin-2 and gamma interferon (IFN-gamma) mRNA and protein expression in mitogen-stimulated human peripheral blood lymphocytes. For comparison, novobiocin and the antineoplastic drug etoposide were also included in the study. CP-115,953 (25 microM) enhanced interleukin-2 mRNA levels up to 8-fold and IFN-gamma mRNA concentrations up to 6.5-fold. In contrast, ciprofloxacin (282 microM) induced mRNAs for interleukin-2 and IFN-gamma up to 20-fold and 7.8-fold, respectively. However, CP-115,953 showed more prolonged kinetics of IFN-gamma mRNA production than ciprofloxacin. At high concentrations (> or = 141 microM), ciprofloxacin was a greater inducer of interleukin-2 production and exhibited a higher level of stimulatory action than CP-115,953 on IFN-gamma synthesis. At low concentrations, however, CP-115,953 (< or = 25 microM) was more potent than ciprofloxacin in inducing interleukin-2 and IFN-gamma synthesis. Etoposide or novobiocin did not influence cytokine mRNA expression. Thus, among the topoisomerase II inhibitors tested, fluoroquinolones are unique in stimulating cytokine synthesis in lymphocyte cultures.

Anti-Infective Agents↗
PubMed1995

Serum antibody response to proteins of Moraxella (Branhamella) catarrhalis in patients with lower respiratory tract infection.

We searched for antibodies against Moraxella (Branhamella) catarrhalis proteins in the sera of patients with lower respiratory tract infection. Sera from 48 patients with M. catarrhalis and 39 patients without M. catarrhalis in their lower respiratory tract specimens were studied by a gel electrophoresis-immunoperoxidase technique; sera from 23 healthy adult blood donors were also included. Immunoglobulin G (IgG) antibodies against a 28-kDa protein were found significantly more frequently in patients with M. catarrhalis in lower respiratory tract specimens (71%) than in patients without M. catarrhalis in lower respiratory tract specimens (28%) or healthy adult blood donors (22%). Seroconversion, from the acute to the convalescent stages, occurred in at least eight patients with M. catarrhalis and in one patient without detectable M. catarrhalis. IgG antibodies against other M. catarrhalis proteins were found in most sera, including those obtained from blood donors. By adsorption experiments the 28-kDa protein was demonstrated to be surface exposed. IgM antibodies against an 85-kDa protein were found in serum from one patient from whom M. catarrhalis and Streptococcus pneumoniae were isolated from the lower respiratory tract, while IgA antibodies against M. catarrhalis proteins could not be detected in any serum specimen.

Acute Disease↗
PubMed1995

The gene encoding protein D (hpd) is highly conserved among Haemophilus influenzae type b and nontypeable strains.

The molecular conservation of a surface-exposed lipoprotein, protein D, of Haemophilus influenzae was studied by cloning and sequencing of the gene encoding protein D from three encapsulated type b strains and three nontypeable strains of H. influenzae. These nucleotide sequences were analyzed with previously reported sequences from one type b strain and one nontypeable strain. The nucleotide sequences and the deduced amino acid sequences for protein D were highly conserved. The deduced amino acid sequence (364 amino acids) of protein D from six strains differed only in two amino acids near the C-terminal end. The remaining two strains, one type b and one nontypeable, differed from the consensus sequence in 7 amino acids each. Protein D is 64 and 36% identical and 77 and 56% similar to the glycerophosphodiester phosphodiesterases (GlpQ) of Escherichia coli and Bacillus subtilis.

Amino Acid Sequence↗
PubMed1994

Superinduction of cytokine gene transcription by ciprofloxacin.

In addition to their antibacterial properties, certain antibiotics are also biologic response modifiers. The fluorinated 4-quinolone, ciprofloxacin, for example, up-regulates IL-2 and IFN-gamma production in PBLs stimulated in vitro. In the present study, ciprofloxacin was shown to increase the levels of mRNA for IL-1 alpha, IL-2 and its receptor, IFN-gamma, IL-3, IL-4, granulocyte-macrophage/CSF, TNF-alpha, and lymphotoxin. As investigated with different T cell mitogens and alloantigens, the up-regulation of IL-2 production by ciprofloxacin was found to be independent of the mode of stimulation. Analysis of transcription activity showed that ciprofloxacin enhances IL-2 gene induction. The concentrations of nuclear factor of activated T cells (NF-AT-1) and AP-1 were also found to be increased by ciprofloxacin. Thus, ciprofloxacin interferes with a regulative pathway common to several cytokines.

Ciprofloxacin↗
PubMed1994

Evidence that the antibiotic ciprofloxacin counteracts cyclosporine-dependent suppression of cytokine production.

The fluoroquinolone antibiotic ciprofloxacin (cipro) has been reported to upregulate interleukin 2 and interferon-gamma production in lectin-stimulated lymphocytes. The aim of this study was to elucidate whether cipro and the immunosuppressive agent CsA have antagonistic action on cytokine synthesis. Accumulation of IL-2 and IFN-gamma protein and mRNA were analyzed in polyclonally (PHA or Con A) or alloantigen-stimulated human peripheral blood lymphocytes. CsA added simultaneously with PHA partially blocked cytokine synthesis. The present study also shows that cipro supplemented with CsA and PHA resulted in significant higher concentrations of IL-2 (up to 60 times) and IFN-gamma (4.3 times) as compared with PHA and CsA alone. Similar results were obtained with primary mixed lymphocyte reactions. In parallel, a greater amount of IL-2 and IFN-gamma mRNA was observed in lymphocytes incubated with both cipro and CsA as compared with CsA alone. Our results reveal that CsA-dependent inhibition of both IL-2 and IFN-gamma expression is counteracted by high concentrations of cipro. These findings may be of importance in clinical transplantation.

Blotting, Northern↗
PubMed1994

Effect of lactoferrin on interaction of Prevotella intermedia with plasma and subepithelial matrix proteins.

A lactoferrin-binding protein with an estimated molecular mass of 57 kDa was identified in the cell envelope of Prevotella intermedia by gel electrophoresis and Western-blot analysis. Peroxidase-labeled bovine lactoferrin and human lactoferrin showed similar specific binding to this protein. Whole cells of P. intermedia were also examined for interactions with 5 125I-labeled plasma and subepithelial matrix proteins. A high degree of binding was found with fibronectin, collagen type I and type IV and laminin, whereas a moderate interaction was detected with fibrinogen. The ability of bovine lactoferrin to affect the interactions of the above proteins with P. intermedia was examined. In the presence of unlabeled bovine lactoferrin, a dose-dependent inhibition of binding was observed with all 5 proteins tested. Unlabeled bovine lactoferrin also dissociated the bacterial complexes with these proteins. The complexes with laminin or collagen type I were more effectively dissociated than fibronectin or fibrinogen, whereas the interaction with collagen type IV was affected to a lesser extent. A strain-dependent variation in the effect of bovine lactoferrin was observed. These data establish the presence of a specific lactoferrin-binding protein in the cell envelope of P. intermedia. The ability of lactoferrin to inhibit the binding of some plasma and subepithelial matrix proteins to P. intermedia could be a protective mechanism against the establishment of this pathogen in the periodontal pocket.

Animals↗
PubMed1994

Antimicrobial susceptibility of bacterial isolates in south Sweden including a 13-year follow-up study of some respiratory tract pathogens.

The antibiotic susceptibility of consecutive isolates of the upper respiratory tract pathogens Streptococcus pyogenes, Streptococcus pneumoniae, Haemophilus influenzae, Branhamella catarrhalis, and Staphylococcus aureus, (100 strains of each species collected each year during March through April 1985, 1988 and 1992) to penicillin V, amoxycillin, cefaclor, cefuroxime, doxycycline, erythromycin, and cotrimoxazole was investigated by MIC determination on PDM and PDM II agar. The MICs of the upper respiratory isolates from 1992 supplemented with 100 isolates each of Escherichia coli, Klebsiella spp., Enterobacter cloacae, Proteus mirabilis and Staphylococcus saprophyticus collected during 1992 were determined against the above antibiotics plus cefadroxil, cefpodoxime, roxithromycin, ciprofloxacin, ofloxacin, and BAY Y 3118. Beta-lactamase production was found in 10% of H. influenzae and 80-90% of S. aureus and B. catarrhalis in 1992. Among H. influenzae isolates, non-beta-lactamase-induced resistance to all beta-lactam antibiotics was first detected in 1988 and amounted to 3% of isolates in 1992. Decreased susceptibility of S. preumoniae to penicillin (> or = 0.12 mg/l), co-trimoxazole > or = 32 mg/l, doxycycline (> or = 2 ml/l) and erythromycin (> or = 1 mg/l) was detected in 11%, 7%, and 8%, respectively, in 1992, which is significantly higher than in previous years at the same laboratory. Decreased susceptibility of S. pyogenes to doxycycline and erythromycin was detected in 11% and 9% in 1992. The two most recently developed antibiotics, cefpodoxime and BAY Y 3118, showed high antibacterial activity. The study emphasizes the need to screen for resistance mechanisms such as beta-lactamase production and lowered penicillin affinity.

Anti-Bacterial Agents↗
PubMed1994

Limited effects of temafloxacin compared with ciprofloxacin on T-lymphocyte function.

Temafloxacin increased interleukin-2 production and mRNA levels and enhanced thymidine incorporation in stimulated lymphocyte cultures. Gamma interferon mRNA levels were unaffected. Temafloxacin also stimulated interleukin-2 gene induction, as revealed in a chloramphenicol acetyltransferase reporter gene system. However, temafloxacin exerted significantly weaker effects in these respects than did ciprofloxacin.

Anti-Infective Agents↗
PubMed1994

Protein D, the glycerophosphodiester phosphodiesterase from Haemophilus influenzae with affinity for human immunoglobulin D, influences virulence in a rat otitis model.

A mutant lacking the ability to express the surface-exposed lipoprotein protein D was constructed by linker insertion and deletion mutagenesis of a cloned DNA insert containing the protein D structural gene from a nontypeable Haemophilus influenzae strain (NTHi). An isogenic NTHi mutant was isolated after transformation of genetically competent bacteria. The transformant was unreactive to a protein D-specific monoclonal antibody in a colony immunoassay. In addition, the mutant lacked the ability to synthesize detectable levels of protein D by protein staining, immunoblot methods, glycerophosphodiester phosphodiesterase activity, and binding studies of radiolabelled immunoglobulin D. The isogenic protein D-deficient mutant was compared with its parental strain for its ability to induce experimental otitis media in rats challenged with bacteria. An approximately 100-times-higher concentration of the mutant compared with that of the wild-type strain was required in order to cause otitis among all rats challenged with that given dose. The protein D mutant exhibited a generation time that was equal to that of the wild-type strain in complex broth medium. No difference in lipopolysaccharide expression was found between the mutant and the parental strain. These results suggest that protein D may influence the pathogenesis of NTHi in the upper respiratory tract.

Animals↗
PubMed1994

Lactoferrin binds to porins OmpF and OmpC in Escherichia coli.

Lactoferrin (Lf) is an iron-binding antimicrobial protein present in milk and on mucosal surfaces, with a suggested role in preimmune host defense. Certain strains of Escherichia coli (bacterial whole cells) demonstrate specific interaction with 125I-labeled Lf. A band with a mass of approximately 37 kDa, which was reactive with horseradish peroxidase-labeled Lf, was identified in the boiled cell envelope and outer membrane preparations of an Lf-binding E. coli strain, E34663, and a non-Lf-binding strain, HH45, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting (immunoblotting). Such a band was not detected in the unboiled native cell envelope and outer membrane preparations. The molecular mass and the property of heat modifiability suggested that the Lf-binding proteins were porins. The native trimeric form of porin OmpF isolated from strain B6 and its dissociated monomeric form both reacted with horseradish peroxidase-labeled Lf and with monoclonal antibodies specific for OmpF. Furthermore, by using E. coli constructs with defined porin phenotypes, OmpF and OmpC were identified as the Lf-binding proteins by urea-SDS-PAGE and Western blotting and by 125I-Lf binding studies with intact bacteria. These data establish that Lf binds to porins, a class of well-conserved molecules common in E. coli and many other gram-negative bacteria. However, in certain strains of E. coli these pore-forming proteins are shielded from Lf interaction.

Escherichia coli↗