| 1. |
- Wold, Agnes E, 1955, et al.
(författare)
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Attachment of Escherichia coli via mannose- or Gal alpha 1----4Gal beta-containing receptors to human colonic epithelial cells.
- 1988
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Ingår i: Infection and immunity. - 0019-9567. ; 56:10, s. 2531-7
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Tidskriftsartikel (refereegranskat)abstract
- The role of bacterial adhesion for the maintenance of the large-intestinal microflora has not been established. In this study, colonic cells from the adenocarcinoma cell line HT-29 or from surgical specimens were tested for the ability to bind Escherichia coli. The E. coli strains were manipulated by transformation or by mutagenesis to express either mannose-specific type 1 fimbriae (strains 506 MS and HU742) or Gal alpha 1----4Gal beta-specific P fimbriae (506 MR and HU824). Binding to HT-29 cells was seen with strains of either receptor specificity and was inhibited by alpha-methyl mannoside or globotetraosylceramide (GalNAc beta 1----3Gal alpha 1----4Gal beta 1----4Glc-ceramide), respectively. The Gal alpha 1----4Gal beta-specific strains interacted with a loosely surface-associated substance, which was sensitive to mechanical treatment and incubation at 37 degrees C, while the mannose-specific strains bound both directly to the cell and to the loosely associated substance. Isolated colonic epithelial cells bound the mannose-specific bacteria in high numbers, while the attachment of the Gal alpha 1----4Gal beta-specific strains depended on the elution method. Cells eluted sequentially with magnetic stirring were unable to bind the Gal alpha 1----4Gal beta-specific bacteria, while elution by a more gentle method resulted in binding of these strains to material loosely associated with the epithelial cells. Thus, the binding pattern of isolated colonic epithelial cells paralleled that of the HT-29 cell line. Conceivably, binding to mannose- and Gal alpha 1----4Gal beta-containing receptors could contribute to the maintenance of E. coli in the human large intestine.
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| 2. |
- Björck, Lars, et al.
(författare)
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Bacterial growth inhibited by a synthetic inhibitor based upon the structure of a human proteinase inhibitor
- 1989
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 337:6205, s. 385-386
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Tidskriftsartikel (refereegranskat)abstract
- Cysteine proteinases are important not only in the intracellular catabolism of peptides and proteins1 and in the processing of prohormones and proenzymes2,3, but also in the penetration of normal human tissue by malignant cells4 and possibly microorganisms5, including viruses. Cystatin C is a human cysteine proteinase inhibitor present in extracellular fluids6. We have synthesized peptide derivatives mimicking the proposed proteinase-binding centre of cystatin C7 and find that they irreversibly inhibit cysteine proteinases. Several bacteria produce proteinases, so we tested a tripeptide derivative (Z-LVG-CHN2) for in vitro anti-bacterial activity against a large number of bacterial strains belonging to thirteen different species. It was found to inhibit specifically the growth of all strains of group A streptococci. The susceptibility of these human pathogens to the peptide was compared with that to well-established anti-streptococcal antibiotics such as tetracy-cline and bacitracin. Moreover, the peptide was active in vivo against group A streptococci: mice injected with lethal doses of these bacteria were cured by a single injection of Z-LVG-CHN2. The cysteine proteinase produced by group A streptococci was isolated and found to be inhibited by Z-LVG-CHN2; moreover, excess proteinase relieved the growth inhibition caused by the peptide derivative, suggesting that the antibacterial activity of Z-LVG-CHN2 is due to inhibition of this cysteine proteinase. This strategy of blocking proteinases with peptide derivatives that mimic naturally occurring inhibitors could be useful in the construction of new agents against other microorganisms, including viruses.
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| 3. |
- Alestig, Kjell, 1931, et al.
(författare)
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Ceftazidime for Pseudomonas meningitis.
- 1985
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Ingår i: Lancet (London, England). - : Elsevier BV. - 0140-6736. ; 1:8421, s. 161-2
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Back, S E, et al.
(författare)
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Age dependence of renal function: clearance of iohexol and p-amino hippurate in healthy males
- 1989
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Ingår i: Scandinavian Journal of Clinical & Laboratory Investigation. - 1502-7686. ; 49:7, s. 641-646
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Tidskriftsartikel (refereegranskat)abstract
- Iohexol, a newly developed non-ionic contrast agent, has been recently documented as a reliable glomerular filtration marker. This study describes the age dependence of the single injection clearance of iohexol in a sample of healthy male volunteers ranging from 21 to 77 years of age. In parallel, renal plasma flow was studied by measuring the total clearance of p-amino hippuric acid administered as a continuous infusion. In subjects older than 50 years a negative correlation to age was found for both p-amino hippuric acid and iohexol clearance, with a reduction of 52 ml/min and 12 ml/min per decade, respectively, whereas no age dependence was found for younger subjects. Correlation between p-amino hippuric acid and iohexol clearances was 0.81. However, the filtration fraction, defined as the ratio of iohexol to p-amino hippuric acid clearance, was higher in the elderly subjects. A consistent discrepancy was found between total and renal clearances of p-amino hippuric acid, indicating significant renal metabolism. Renal clearance of creatinine was poorly correlated to iohexol clearance and did not show any relationship to age.
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| 5. |
- Békássy, Albert, et al.
(författare)
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Arterial occlusion due to Listeria meningoencephalitis in an immunocompromised boy
- 1987
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 1651-1980 .- 0036-5548. ; 19:4, s. 485-489
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Tidskriftsartikel (refereegranskat)abstract
- Sequential CAT scan studies of the brain were performed in a 7-year-old boy with Listeria monocytogenes serotype 1 meningoencephalitis. The infection occurred while he was receiving maintenance chemotherapy for T-cell non-Hodgkin lymphoma. A lesion in the right hemisphere during the infection resulted in an excessive enlargement of the right ventricle 10 months later, most probably caused by arterial occlusion.
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| 6. |
- Bodelsson, Mikael, et al.
(författare)
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Cooling augments contractile response to 5-hydroxytryptamine via an endothelium-dependent mechanism
- 1989
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Ingår i: Blood Vessels. - 0303-6847. ; 26:6, s. 347-359
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between cooling and vasoactive substances, e.g. 5-hydroxytryptamine (5-HT), plays an important role in the pathophysiology of cold-induced vasospasm. Our objective was to study the effect of cooling on the 5-HT vascular response, classify the involved 5-HT receptors, and to analyze the role of the endothelium. Ring segments from the rat jugular vein, a preparation without alpha-adrenergic receptors, were suspended in organ baths to record the circular motor activity. The temperature was initially 37 degrees C and was thereafter either continuously lowered to 10 degrees C or kept constant at different temperatures within this range. 5-HT at low concentrations (10(-11) to 3 x 10(-8) M) induced relaxation at 37 degrees C in segments precontracted by prostaglandin F2 alpha. The relaxation was recognized to be mediated via an endothelium-dependent 5-HT1-like receptor mechanism presumably involving the release of endothelium-derived relaxing factor (EDRF). Cooling to 29 and 20 degrees C diminished the relaxation, probably due to an attenuated release of EDRF. 5-HT at concentrations of more than 10(-8) M induced a contraction in all vessels at 37 degrees C mediated via a 5-HT2 receptor. An increased 5-HT-induced contraction was seen at temperatures below 37 degrees C in vessels with an intact endothelium. Endothelial denudation diminished the cold-induced enhancement of the contraction to 5-HT. These studies suggest that endothelial mechanisms contribute to a cold-induced augmented response to 5-HT.
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| 7. |
- Falkenberg, C, et al.
(författare)
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Purification of streptococcal protein G expressed by Escherichia coli by high performance liquid affinity chromatography using immobilized immunoglobulin G and albumin
- 1987
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Ingår i: Biomedical Chromatography. - : Wiley. - 0269-3879 .- 1099-0801. ; 2:5, s. 5-221
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Tidskriftsartikel (refereegranskat)abstract
- A one-step HPLC method was developed for the purification of protein G, a cell wall molecule from group C and G streptococci with immunoglobulin G- and albumin-binding properties. Lysed Escherichia coli bacteria infected with lambda-phages containing the protein G gene from group G streptococci were used as a starting material for the preparations. The lysate was applied to a column with immobilized human immunoglobulin G or human serum albumin. Protein G was selectively bound and eluted at pH 2.0. A 750-fold purification was achieved. Sodium dodecylsulfate + polyacrylamide gel electrophoresis showed that the highly purified protein G consisted of three sets of doublets with the apparent molecular weight of 64 and 67, 56 and 58, and 45 and 47 kilodaltons, respectively. A specific method for quantitation of small amounts of protein G was developed and used for specific tracing of the protein after the affinity chromatography. Goat polyclonal antibodies were bound to an antigen coated to the plastic walls of microtiter plates, causing the Fc-region of the immunoglobulins to be directed outwards. Unknown samples of protein G were then allowed to compete with radio-iodinated protein G (solid phase radioassay) or protein G coupled to alkaline phosphatase (enzyme linked sorbent assay) for the Fc-regions.
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| 8. |
- Grahn, Eva, 1954-
(författare)
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Bacteriological aspects of treatment failures in streptococcal tonsillitis
- 1986
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- ß-hemolytic streptococci persist in 10-25% of patients with acute streptococal tonsillitis (about 10.000-25.000 per year in Sweden) in spite of treatment with a recommended dosage and schedule of Phenoxymethylpenicillin. The aim of the study was to investigate different bacteriological factors involved in treatment failures of streptococcal tonsillitis. Patients included in the study were 33 patients who underwent tonsillectomy, 62 persons included in a tonsillitis epidemic outbreak, 267 tonsillitis patients contacting the ENT-clinic, Sahlgrenska Hospital, Göteborg, and 20 healthy volunteers taking Phenoxymethylpenicillin. It was found that the Steer's steel pin replicator was a useful tool to study interference between a- and ß-hemolytic streptococci and a guantitative differen ce in. the inhibitory capacity of the different a-strains was noted, a-streptococci with a strong inhibitory capacity on ß-streptococci were isolated mainly from individuals seemingly resistant to ß-streptococcal tonsillitis, while from patients with repeated tonsillitis no or low numbers of inhibiting a-streptococci were demonstrated. Patients with clinical treatment failure had less a-streptococci with inhibiting capacity on their own ß-streptococcal strain compared with the healthy carriers. These treatment failures also showed beta-lactamase activity in their saliva pellet significantly more often than patients in the control groups. In volunteers penicillin was released from ordinary sugar coated tablets already in the mouth resulting in a decrease of the a-strep- tococcal flora. A synergistic effect on ß-hemolytic killing by low concentration of penicillin and inhibition of a-streptococci was noted in vitro and in vivo. Penicillin tolerance was registered in most strains from the treatment failure group, but in none of the strains from the group of successfully treated patients. A co-operation between different bacteriological factors (bacterial interference, beta-lactamase production, penicillin tolerance) seems to be important in treatment failures of streptococcal tonsillitis.
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