| 1. |
- Ekdahl, Karl, et al.
(författare)
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Bronchoscopic diagnosis of pulmonary infections in a heterogeneous, nonselected group of patients
- 1993
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Ingår i: Chest. - 1931-3543. ; 103:6, s. 1743-1748
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Tidskriftsartikel (refereegranskat)abstract
- Fiberoptic bronchoscopy with bronchoalveolar lavage and protected specimen brush technique has become an established method for etiologic diagnosis in severe forms of pulmonary infections during recent years. In this study, including 62 bronchoscopies in 53 patients, a standardized program, covering all important pulmonary pathogens, has been evaluated in a heterogeneous group of patients. Results providing therapeutic guidelines were obtained in 53 percent (16/30) of the immunocompromised patients (including 5 bronchoscopies on HIV-positive patients), but only 19 percent (6/32) of the immunocompetent patients (p < 0.001). We conclude that bronchoscopy is of great value for diagnosing pulmonary infections in immunocompromised patients. In immunocompetent patients, the diagnostic yield is lower and the indication for bronchoscopy must be established for each individual patient based on clinical importance, resources, and risk. When bronchoscopy is performed, we believe that a standardized program like ours reduces the risk of missing important pathogens.
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| 2. |
- Abate, Getahun, et al.
(författare)
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Direct colorimetric assay for rapid detection of rifampin-resistant Mycobacterium tuberculosis
- 2004
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Ingår i: Journal of Clinical Microbiology. - 1098-660X. ; 42:2, s. 871-871
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Tidskriftsartikel (refereegranskat)abstract
- The colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was standardized for direct detection of rifampin-resistant Mycobacterium tuberculosis in sputum samples. The sensitivity and specificity of the direct MTT assay matched those of the standard indirect susceptibility assay on 7H10 medium, and interpretable results were obtained for 98.5% of the samples within 2 weeks. Traditional methods of in vitro drug susceptibility testing are time consuming and laborious. Susceptibility tests on clinical isolates require 6 to 9 weeks, and tests conducted directly on smear-positive samples take about 3 weeks (International Union Against Tuberculosis and Lung Disease, The public health service national tuberculosis reference laboratory and the national laboratory network. Minimum requirements, role and operation in a low-income country, Paris, France, 1998, and P. T. Kent and G. P. Kubica, Public health mycobacteriology. A guide for the level III laboratory, Centers for Disease Control and Prevention, Atlanta, Ga., 1985). More-rapid methods are available but are very expensive for routine use under program conditions in countries with high levels of tuberculosis endemicity.
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| 3. |
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| 4. |
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| 5. |
- Björck, Lars, et al.
(författare)
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On the interaction between beta 2-microglobulin and group A streptococci
- 1984
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Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 1365-3083 .- 0300-9475. ; 20:1, s. 69-79
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Tidskriftsartikel (refereegranskat)abstract
- beta 2-microglobulin (beta 2m) was found to interact with many group A streptococcal strains. The interaction appeared to require multipoint attachment, since monomeric beta 2m in solution showed no binding, whereas both beta 2m monomers bound to liposomes, and beta 2m in aggregates showed affinity for the bacteria. Aggregated HLA antigens (-A, -B and -C) and aggregated beta 2m exhibited the same binding patterns when tested in binding experiments with various group A streptococcal strains. Furthermore, beta 2m aggregates in excess completely blocked the binding of aggregated HLA antigens, thereby demonstrating that beta 2m is able to interact with streptococcal surface structures also when it is part of the HLA antigen complex. M protein-positive group A streptococcal strains bound significantly more beta 2m than M protein-negative variants of these strains. Purified M 12 protein partly inhibited the binding of radiolabelled beta 2m aggregates to whole streptococci, and in gel filtration and affinity chromatography experiments, the M 12 protein interacted with beta 2m. These various data suggest that the interaction between beta 2m and group A streptococci could be mediated by M protein. Lipoteichoic acid (LTA) is a constituent of the streptococcal cell wall that has been reported to form complexes with M protein at the bacterial cell surface. However, LTA did not influence the interaction between beta 2m and streptococci, suggesting that the binding of beta 2m to streptococcal M protein represents a pure protein-protein interaction. In vivo such an interaction could be established between infecting streptococci and host cells. Among 45 strains of different M types large differences in beta 2m binding were recorded, whereas among 60 strains of the classical nephritogenic M types 12 and 49, all were highly beta 2m-reactive, which points towards a role for beta 2m in streptococcal pathogenicity.
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| 6. |
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| 7. |
- Brimnes, J, et al.
(författare)
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Reactions of N-N and N-O compounds with horseradish peroxidase and peroxidases from Mycobacterium tuberculosis
- 1999
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Ingår i: APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. - 1600-0463. ; 107:6, s. 555-565
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Tidskriftsartikel (refereegranskat)abstract
- Several N-N-and N-O-containing compounds were analysed for their ability to act as substrates for horseradish peroxidase and peroxidases in Mycobacterium tuberculosis extracts. Aminoguanidine, diaminoguanidine, isoniazid, hydroxylamine and hydrazine were found to be weak substrates for horseradish peroxidase in reaction I and to inhibit the reaction of horseradish peroxidase with hydrogen peroxide. The same compounds inhibited the reaction of Mycobacterium tuberculosis peroxidase-catalase with hydrogen peroxide, and hydroxylamine was found to be a weak substrate for this enzyme. In growth inhibition experiments, diaminoguanidine inhibited the growth of M. tuberculosis H37Rv at 50 microg/mL, but not the growth of two isoniazid-resistant strains. Isonicotinic acid hydroxamate inhibited the reaction of the peroxidases with hydrogen peroxide, but was not itself a substrate and had no growth-inhibitory effects. On the basis of these results we suggest that the effect of isoniazid on growth of M. tuberculosis results from increased oxidative stress due to inhibition of catalase-peroxidase as well as from generation of toxic radicals with the structure [structure in text].
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| 8. |
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| 9. |
- Gebre, Negussie, et al.
(författare)
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Improved microscopical diagnosis of pulmonary tuberculosis in developing countries
- 1995
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Ingår i: Transactions of the Royal Society of Tropical Medicine and Hygiene. - : Oxford University Press (OUP). - 1878-3503 .- 0035-9203. ; 89:2, s. 191-193
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Tidskriftsartikel (refereegranskat)abstract
- The diagnosis of pulmonary tuberculosis (TB) relies on the bacteriological examination of sputum. However, microscopy of smears made directly from sputum has a low sensitivity and there is an urgent need for improved methods. We have compared microscopy of smears made directly from sputum with microscopy after liquefaction of sputum with household bleach (NaOCl) and concentration of bacteria by centrifugation. In 3 studies performed in Ethiopia and India, the use of the NaOCl method increased the number of samples positive for acid-fast bacilli by more than 100%. The technique is appropriate for developing countries and its application would increase the efficiency of TB control programmes. As a potent disinfectant, NaOCl also has the advantage of lowering the risk of laboratory infection.
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| 10. |
- Holst, Elisabet, et al.
(författare)
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In vitro activities of cefcanel and some other cephalosporins against Pasteurella multocida
- 1989
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Ingår i: Antimicrobial Agents and Chemotherapy. - 1098-6596. ; 33:12, s. 2142-2143
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-five strains of Pasteurella multocida from humans and animals were tested for susceptibility to five cephalosporins by a broth dilution method. Cefcanel showed high activity against all isolates (MIC and MBC, less than or equal to 0.64 micrograms/ml). The corresponding figure for cefaclor and cefuroxime was 2.56 micrograms/ml. Cefadroxil and cephalexin were the least active compounds tested.
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| 11. |
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| 12. |
- Larsson, Inger, et al.
(författare)
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Interferon production in glia and glioma cell lines
- 1978
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Ingår i: Infection and Immunity. - 1098-5522. ; 22:3, s. 786-789
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Tidskriftsartikel (refereegranskat)abstract
- Interferon (IF) was produced in glia and glioma cell lines in titers comparable to those produced by human fibroblasts. It was inducible by both Sendai virus and polyriboinosinic:polyribocytidylic acid. "Superinduction" resulted in up to 500-fold-higher titers of IF. The IF appeared to be of the fibroblast type, as revealed by experiments using heat treatment, assay of antiviral activity in heterologous cell lines, and neutralization with specific antisera. Since large amounts of IF may easily be produced with glioma cell lines, such cells may be suitable for mass production of IF.
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| 13. |
- Lorentzon, Siri, et al.
(författare)
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The diagnosis of bacteriuria during pregnancy
- 1990
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Ingår i: Scandinavian Journal of Primary Health Care. - : Informa UK Limited. - 0281-3432 .- 1502-7724. ; 8:2, s. 81-83
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Tidskriftsartikel (refereegranskat)abstract
- Three diagnostic tests, Nitur, Urobact, and Uricult, were evaluated in the detection of bacteriuria in 865 pregnant women. As reference method agar culture was performed. Heavy growth (greater than 10(5) CFU/ml) of urinary tract bacteria was considered a true positive result and demonstrated in 58 (6.7%) of the women, 14 of whom had gram-negative rods. The sensitivity of the nitrite test was extremely low (0.13). The test gave negative results in eight of 17 specimens yielding heavy growth of Escherichia coli or Proteus mirabilis. Although the Urobact test was highly sensitive as regards gram-negative infection, it had an unacceptably low (0.27) predictive value in positive tests. The sensitivity of the Uricult test was low (0.35) in this study. The predictive value (0.50) of a positive test result may be acceptable, since just over half of the false positive results were explainable by moderate growth of urinary tract pathogens (10(4)-10(5) CFU/ml). It is argued that semi-quantitative urine culture may be preferable to the rapid diagnostic methods studied for the screening of bacteriuria in pregnant women.
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| 14. |
- Lundgren, E, et al.
(författare)
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Effects of leukocyte and fibroblast interferon on events in the fibroblast cell cycle
- 1979
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Ingår i: Journal of General Virology. - : Microbiology Society. - 1465-2099 .- 0022-1317. ; 42:3, s. 589-595
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Tidskriftsartikel (refereegranskat)abstract
- Serum-depleted human foetal skin fibroblasts were stimulated by addition of 10% foetal calf serum to proliferate synchronously for at least one cell cycle. This proliferation was suppressed by leukocyte or fibroblast interferon (IF), which prolonged the G1 phase and diminished the rate of DNA synthesis during the S phase in a dose-dependent manner. When used in identical concentration, as judged in terms of units of antiviral activity, fibroblast IF had more pronounced effects on cell cycle events than leukocyte IF. Interferon exerted its effect in early G1, before the cells were irreversibly committed to DNA synthesis.
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| 15. |
- Miörner, Håkan, et al.
(författare)
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30 år av framgångsrik mykobakterieforskning. AHRI i Addis Abeba unik forskningsmiljö i u-land
- 1999
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Ingår i: Läkartidningen. - 0023-7205. ; 96:6, s. 585-587
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Tidskriftsartikel (refereegranskat)abstract
- The Armauer Hansen Research Institute (AHRI) in Addis Abeba, Ethiopia, was established by the Swedish and Norwegian Save the Children organisations in collaboration with the University of Bergen, with the principal objective of pursuing basic research in leprosy. The institute has a commendable record of achievement, and has made significant contributions to our understanding of leprosy and its control, and to the training of scientists from Ethiopia and other African countries. Recently, the Ethiopian, Swedish and Norwegian governments agreed to continue supporting the AHRI as an autonomous research centre. Its main objectives will be to conduct research in mycobacterial diseases, particularly tuberculosis, and to promote the enhancement of human resources in health research through instruction, supervision, and scientific collaboration.
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| 16. |
- Miörner, Håkan, et al.
(författare)
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Assay of type-specific M antigens on whole group A streptococci
- 1984
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Ingår i: European journal of clinical microbiology. - 0722-2211. ; 3:1, s. 14-18
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Tidskriftsartikel (refereegranskat)abstract
- A novel radioimmunoassay of type-specific M antigens on whole group A streptococcal cells is described. Absorbed rabbit anti-M antisera directed against M types 12 and 49 were used for determining M antigens on intact bacterial organisms. Staphylococcal protein A labelled with 125I was used as an anti-antibody reagent. The absorbed antisera were tested against ten homologous and 48 heterologous serotypes. All homologous serotypes gave an unequivocal reaction distinct from the weaker reaction with the heterologous serotypes. The type-specificity of the reaction was confirmed by the removal of type-specific antibodies after absorption to purified M protein coupled to Sepharose 4B. The results indicate that the described method is a simple and reliable technique for the recognition of M types of group A streptococci and offers a valuable tool for studies of M antigen in situ.
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| 17. |
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| 18. |
- Miörner, Håkan, et al.
(författare)
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Diagnosis of tuberculous meningitis: a comparative analysis of 3 immunoassays, an immune complex assay and the polymerase chain reaction
- 1995
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Ingår i: Tubercle and Lung Disease. - : Elsevier BV. - 0962-8479. ; 76:5, s. 381-386
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To compare 3 immunoassays, an immune complex assay, and an application of the polymerase chain reaction (PCR) for the diagnosis of tuberculous meningitis (TBM). MATERIAL: Cerebrospinal fluid (CSF) from 33 patients with TBM and from 34 control patients with infectious and non-infectious CNS diseases was analysed. RESULTS: The antibody immunoassays were either nonspecific or insensitive. However, detection of mycobacterial IgG immune complexes correlated strongly with infection, as they were detected in the CSF from 64% of the patients with TBM compared to only 3 (9%) of the control samples. PCR analysis, using Mycobacterium tuberculosis-specific oligonucleotide primers, also strongly correlated with infection, as DNA was amplified from 54% of the samples from patients with TBM, but from only 2 (6%) of the control samples. Both 'false positive' samples were also positive in the immune complex assay and came from 2 patients with otogenic brain abscesses. It is conceivable that these patients suffered from otogenic tuberculosis with secondary non-mycobacterial meningitis. When combining the immune complex assay with DNA-detection by PCR, 100% of the culture positive and 74% of culture negative samples were found to be positive, while maintaining a high specificity. CONCLUSION: Parallel analysis to detect mycobacterial immune complexes and M. tuberculosis-specific DNA by PCR from the CSF of patients may offer a sensitive and specific tool for the diagnosis of TBM.
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| 19. |
- Miörner, Håkan, et al.
(författare)
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Effect of specific binding of human albumin, fibrinogen, and immunoglobulin G on surface characteristics of bacterial strains as revealed by partition experiments in polymer phase systems
- 1980
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Ingår i: Infection and Immunity. - 1098-5522. ; 29:3, s. 879-885
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Tidskriftsartikel (refereegranskat)abstract
- Four strains of gram-positive cocci with different combinations of positive binding of human proteins were investigated with respect to changes in physicochemical surface properties after specific protein binding. Staphylococcus aureus Cowan I, two group A beta-hemolytic streptococci, and one group G streptococcal strain were studied; they represented three different combinations of reactivity for human serum albumin, human immunoglobulin G, and fibrinogen. Using single-tube partition of bacterial cells in a dextran-polyethylene glycol system of constant polymer concentration but varying ionic compositions, it was possible to detect changes in the partition of bacteria after specific protein binding. There was a correlation between the binding of radiolabled human proteins to the bacterial strains and the effect of human proteins on the partition of the bacteria in the phase systems. Thus, the specific binding of proteins to the bacteria changes their physicochemical surface properties. These types of bacteria-protein interactions may play an important role in modulating host-parasite relationships.
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| 20. |
- Miörner, Håkan, et al.
(författare)
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Improved isolation of mycobacteria other than Mycobacterium tuberculosis on isoniazid-containing Lowenstein-Jensen medium
- 1988
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Ingår i: European Journal of Clinical Microbiology & Infectious Diseases. - 1435-4373. ; 7:1, s. 47-49
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Tidskriftsartikel (refereegranskat)abstract
- The benefit of including isoniazid-containing Lowenstein-Jensen medium for primary isolation of mycobacteria was evaluated in 3,726 clinical specimens. This media increased the primary isolation of mycobacteria other than Mycobacterium tuberculosis by 9.2%, facilitated macroscopical reading and aided presumptive identification of the isolated mycobacteria.
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| 21. |
- Miörner, Håkan, et al.
(författare)
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Isoelectric points and surface hydrophobicity of Gram-positive cocci as determined by cross-partition and hydrophobic affinity partition in aqueous two-phase systems
- 1982
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Ingår i: Infection and Immunity. - 1098-5522. ; 36:1, s. 227-234
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Tidskriftsartikel (refereegranskat)abstract
- Thirty-nine streptococcal strains belonging to groups A, C, and G and 12 staphylococcal strains were investigated with respect to surface charge and hydrophobicity. Isoelectric points of the bacteria were determined by cross-partition experiments in dextran-polyethylene glycol two-phase systems containing charged polymers. The results obtained indicate that group A, C, and G streptococci have isoelectric points of pH 3.75 +/- 0.15 standard deviation. Staphylococci show an isoelectric point of around pH 2 and thereby differ markedly from the streptococci. Pretreatment of bacteria with human serum resulted in a significant change in the isoelectric points of streptococci. In a second series of experiments, an aqueous dextran-polyethylene glycol two-phase system containing polyethylene glycol palmitate or stearate was used to study the hydrophobic surface properties of the bacterial cells. The partition of the staphylococci was not influenced by the addition of up to 1% (wt/wt) polyethylene glycol palmitate or stearate, whereas the streptococci showed a large variation in affinity for polyethylene glycol-bound hydrophobic groups. The bacterial strains included in the study were also tested for uptake of human serum proteins. A positive correlation was found between the hydrophobic affinity of group A streptococci and the density of receptors for aggregated beta-2-microglobulin.
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| 22. |
- Miörner, Håkan, et al.
(författare)
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Lipoteichoic acid is the major cell wall component responsible for surface hydrophobicity of group A streptococci
- 1983
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Ingår i: Infection and Immunity. - 1098-5522. ; 39:1, s. 336-343
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Tidskriftsartikel (refereegranskat)abstract
- The contribution of lipoteichoic acid (LTA) to the hydrophobic surface properties of group A streptococci was investigated in aqueous dextran-polyethylene glycol two-phase systems. Enzymatic digestions were performed to characterize the hydrophobic surface structure. The results obtained indicated that LTA is a major factor responsible for the hydrophobic character of the cell surface of group A streptococci. This was further supported by the similarity of partition in polymer two-phase systems between whole group A streptococci and tritiated LTA extracted from a group A streptococcal strain. Surface LTA was also determined on intact organisms by a new method measuring the adsorption of antibodies to LTA to the bacterial surface. A correlation was found between the content of surface LTA and the hydrophobicity of the group A streptococci. We conclude that surface-associated LTA is the major factor determining surface hydrophobicity of group A streptococci.
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| 23. |
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| 24. |
- Miörner, Håkan, et al.
(författare)
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Regulation of mitogen-induced lymphocyte DNA synthesis by human interferon of different origins
- 1978
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Ingår i: Cellular Immunology. - : Elsevier BV. - 0008-8749. ; 35:1, s. 15-24
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Tidskriftsartikel (refereegranskat)abstract
- Human fibroblast and leukocyte interferons were found to suppress lymphocyte mitogenesis induced by optimal doses of phytohemagglutinin and concanavalin A. In certain situations (low doses of mitogen and/or low doses of interferon), however, interferon significantly enhanced mitogenesis. In experiments using varying concentrations of interferon, dose-response curves with different slopes were obtained for fibroblast and leukocyte interferons. The effect of interferon was apparently exerted during early stages of the lymphocyte cell cycle. There was no inhibitory effect of interferon if the lymphocytes were washed with medium before being exposed to mitogen. Interferon increased the binding of radiolabeled mitogens to cells. The results suggest that the immunological effects of interferon are consequences of actions on lymphoid cells. Fibroblast and leukocyte interferons seem to have different modes of action, or to bind differently to target cells. Possible mechanisms for the suppressive and enhancing effects of interferons on lymphoid cells are discussed.
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| 25. |
- Miörner, Håkan, et al.
(författare)
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Surface characteristics of group A streptococci with and without M-protein
- 1984
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Ingår i: Acta pathologica, microbiologica, et immunologica Scandinavica. Section B, Microbiology. - 0108-0180. ; 92:1, s. 23-30
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Tidskriftsartikel (refereegranskat)abstract
- Twenty M protein-positive and eight M protein-negative strains of group A streptococci were investigated with respect to surface hydrophobicity and amount of lipoteichoic acid (LTA). Surface hydrophobicity as determined in polymer two-phase systems varied substantially between individual strains and there was no correlation to the presence of antiphagocytic M protein. The amount of LTA on the surface of the bacteria varied with hydrophobic affinity of the cells. Strains with a high content of surface LTA were found among both M-positive and M-negative streptococci. Cellular and extracellular LTA was estimated on six strains by the ability of hot phenol extracts and culture fluids to sensitize erythrocytes and by rocket immunoelectrophoretic quantitation. Differences in content of surface LTA did not correlate to differences in the total amount of cellular LTA. Pepsin digestion of M-positive group A streptococci at suboptimal pH resulted in a loss of M antigen whereas surface LTA and the hydrophobic interaction liability was retained. The results indicate that the degree of surface hydrophobicity as measured by two-phase partitioning is not correlated to either the type-specific or the antiphagocytic moiety of M protein. The results support the correlation between surface LTA and surface hydrophobicity of group A streptococci.
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