| 1. |
- Janson, Håkan, et al.
(författare)
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Effects on the ciliated epithelium of protein D-producing and -nonproducing nontypeable Haemophilus influenzae in nasopharyngeal tissue cultures
- 1999
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Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 180:3, s. 737-746
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Tidskriftsartikel (refereegranskat)abstract
- A pair of isogenic, nontypeable Haemophilus influenzae strains, one expressing protein D and the other protein D-negative, was compared in their ability to cause damage in a human nasopharyngeal tissue culture model. Damage was assessed by measuring the ciliary beat frequency (CBF) of tissue specimens at 12 h intervals. Cultures inoculated with H. influenzae manifested a decrease in CBF beginning after 12 h, with a maximum decrease after 36 h. The impairment of ciliary function by the protein D-expressing strain was significantly greater than that caused by the protein D-negative mutant (P<.01). Tissue specimens examined by scanning and transmission electron microscopy after 24 h appeared normal. After 48 h of incubation, the protein D-expressing strain caused a significant loss of cilia. These findings suggest that protein D is involved in the pathogenesis of upper respiratory tract infections due to nontypeable H. influenzae, probably by enhancing functional and morphological damage to cilia.
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| 2. |
- Kristinsson, K G, et al.
(författare)
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Effective treatment of experimental acute otitis media by application of volatile fluids into the ear canal
- 2005
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Ingår i: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 191:11, s. 1876-1880
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Tidskriftsartikel (refereegranskat)abstract
- Essential oils are volatile and can have good antimicrobial activity. We compared the effects of oil of basil ( Ocimum basilicum) and essential oil components ( thymol, carvacrol, and salicylaldehyde) to those of a placebo when placed in the ear canal of rats with experimental acute otitis media caused by pneumococci or Haemophilus influenzae. Progress was monitored by otomicroscopic examination and middle ear cultures. The treatment with oil of basil or essential oil components cured or healed 56%-81% of rats infected with H. influenzae and 6%-75% of rats infected with pneumococci, compared with 5.6%-6% of rats in the placebo group. Essential oils or their components placed in the ear canal can provide effective treatment of acute otitis media.
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| 3. |
- Magnúsdóttir, Anna Björk, et al.
(författare)
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Experimental study of the virulence of Streptococcus pneumoniae with reduced susceptibility to penicillin
- 2000
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Ingår i: International Journal of Pediatric Otorhinolaryngology. - 0165-5876 .- 1872-8464. ; 55:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Streptococcus pneumoniae is a major cause of morbidity and mortality in all age groups. In a few years, penicillin non-susceptible pneumococci (PNSP) have emerged worldwide as a new threat. In order to better understand the mechanisms behind the rapid expansion of these strains, the virulence of 10 clinical and two transformed PNSP strains were compared with the virulence of three fully susceptible strains in a mouse model of bacteremia and a rat model of acute otitis media. Serotype, antibiotic susceptibility, and to some extent also genetic profile and growth rate of the strains were investigated before inoculation. The animals were monitored for up to 7 days after challenge by clinical examinations/otomicroscopy and cultures from middle ears and blood. The results of the study demonstrated that the PNSP strains had a significantly reduced ability to persist at the infectious site, and to some extent also to induce infections, compared with fully susceptible strains. The reduction was most evident for strains isolated from sources other than blood. It is therefore possible that other factors than virulence factors are of importance for the ability of PNSP strains to expand.
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