Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A quantitative electron microscopic study was performed to determine the extent of the ciliary surface area of the middle ear epithelium in cats. In normal cats, 97.8% of the middle ear mucosa in the hypotympanum and 45.9% in the upper part of the bulla were covered by cilia. Eustachian tube obstruction (ETO) significantly reduced the ciliary area to 73.1% in the hypotympanum and to 16.2% in the upper part of bulla at 1 week after ETO. Instillation of Escherichia coli lipopolysaccharide (LPS) or cat polymorphonuclear leukocyte (PMN) lysate into the middle ear cavity followed by ETO did not reduce the ciliary area, compared with ETO induced alone. Our results indicate that ETO reduces the ciliary area of the middle ear mucosa and that LPS or neutrophils do not enhance reduction of the ciliary area compared to ETO induced alone in this experimental condition.
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PMID:A quantitative study of the ciliary area of experimental otitis media with effusion in cats. 186 5

The present study focused on structural changes of the round window membrane (RWM) from agents that evoke transient or permanent impairment of the auditory brainstem response when applied into the RW niche. Escherichia coli (E. coli) lipopolysaccharide (LPS) in sterile water (SW) and a 2% suspension of hydrocortisone (CORT), micronized in SW, were instilled into the round window (RW) niche of Sprague-Dawley rats. The morphology of the RWM was analyzed 3 to 21 days after instillation of either substance. Both substances caused minor structural alterations at the light microscopic level. The RWM showed a slight thickening and an invasion of inflammatory cells. At the ultrastructural level, the CORT-treated specimens showed an increased epithelial height and numerous microvilli, whereas the epithelium of the LPS-treated specimens was extended and contained few microvilli resembling those in the normal RWM. We postulate that the RWM may undergo dynamic structural changes when exposed to various agents. The structural alterations per se can influence the passage of substances from the middle ear to the inner ear.
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PMID:Structural changes in the round window membrane following exposure to Escherichia coli lipopolysaccharide and hydrocortisone. 220 57

A quantitative analysis of immunocompetent cells in the middle ear mucosa of mice was carried out by an indirect immunostaining method using various monoclonal antibodies. Mice bred in germ-free, specific pathogen-free, and conventional conditions were used to examine nonimmunized middle ear mucosa. Middle ear mucosae of otitis media-induced mice were also examined. In normal middle ear mucosa, mast cells were substantial, followed by Mac-1-positive cells and lymphocytes. Even though IgA-, IgM-, and Lyt-1-positive cells were seen in the mucosa of conventional mice, IgM-positive cells were seen only in mucosae of specific pathogen-free and germ-free mice. In otitis media-induced mice by inoculation with nontypable Haemophilus influenzae or lipopolysaccharide, Mac-1-positive cells were dominant. Although the numbers of IgM- and Lyt-1-positive cells increased markedly, the numbers of other lymphocyte subsets did not increase until 14 days after inoculation. These findings suggest that the middle ear is immunologically a potential organ as long as it is not exposed to antigenic stimulation. It is considered to be an immunoreactive site only after it has been activated with pathogens.
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PMID:Analysis of immunocompetent cells in the middle ear mucosa. 240 71

Inner ear function was assessed by a frequency-specific (+/-100 Hz) auditory brainstem response (ABR) technique after a single instillation of a suspension of purified E. coli lipopolysaccharide in sterile water into the round window (RW) niche in rats. Instillation of endotoxin caused a transient concentration and tonotopically dependent dysfunction of the inner ear. The largest threshold impairment occurred in the high-frequency region anatomically located close to the RW. At 31.5 kHz the threshold impairment persisted throughout the study. Morphologic damage to the inner ear was not detected at the light microscopic level when using serial sections from decalcified specimens. Our study supports the clinical hypothesis that remnants of non-viable bacteria such as endotoxins, when trapped in the middle ear, can promote middle ear effusion and dysfunction of the inner ear.
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PMID:Inner ear disturbances following inoculation of endotoxin into the middle ear. 264 47

Lipopolysaccharide (10 micrograms/mL) derived from Klebsiella pneumoniae was injected into the middle ear of guinea pigs. The animals were killed painlessly on days 1, 3, and 7 after inoculation, and the mucosal samples from two sites within the tympanic cavity, close to the tympanic orifice and distal to the orifice, were examined for ciliary activity and epithelial morphology. At day 1 and day 3 serous effusion was observed and deterioration of ciliary activity and morphologic changes were observed. No effusion was recognized at day 7, when the ciliary activity in the distal mucosa was still diminished and that in the proximal mucosa had recovered to a normal level. Our data have shown that lipopolysaccharide extracted from K pneumoniae can produce otitis media with effusion in laboratory animals, and dysfunction of cilia due to lipopolysaccharide probably is responsible for the accumulation of middle ear effusion. The mucociliary system is indeed an important defense system and failure of such a system, especially in the mucosa close to the tympanic orifice, can cause the buildup of effusions.
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PMID:Mucociliary disease of the middle ear during experimental otitis media with effusion induced by bacterial endotoxin. 265 18

We inoculated 100 micrograms/ml of lipopolysaccharide (LPS) from Klebsiella pneumoniae into the tympanic cavity of guinea pigs and examined the mucociliary pathology in the middle ear. Serous effusion was observed in the tympanic cavity of every animal on the first, third, and seventh day following the procedure, but the volume of the effusion had decreased to 0.2 ml on day 7. By that time, the ciliary activity in the opening to the eustachian tube within the middle ear had recovered to some extent, but in the middle ear distal to the opening no recovery was apparent. Our results show that cilia close to the eustachian tube play a more significant role in middle ear clearance than those in the middle ear distal to the tube. Compared with our previous study using 10 micron/ml of LPS, this study also demonstrates that inoculations with a higher concentration of LPS induces longer-term middle ear effusions.
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PMID:Experimental otitis media with effusion induced by lipopolysaccharide from Klebsiella pneumoniae: mucociliary pathology of the middle ear. 304 64

A 10-micrograms/mL solution of lipopolysaccharide derived from Klebsiella pneumoniae was inoculated into the middle ears of guinea pigs. The animals were killed painlessly on the first, third, or seventh day after inoculation, and the mucosal samples from the bony portion of the eustachian tube were examined for ciliary activity and epithelial morphology. On the first and third days, when middle ear effusions were present, deterioration of ciliary activity and morphologic changes in the mucociliary system were observed. On the seventh day, when middle ear effusions were absent, the ciliary activity had recovered to normal. Our data show that endotoxin extracted from K pneumoniae can produce otitis media with effusion and that dysfunction of cilia caused by endotoxin is a factor responsible for the manifestation of otitis media.
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PMID:Functional disorder of eustachian tube in experimental otitis media with effusion following inoculation of bacterial endotoxin. 304 30

The discovery of endotoxin in effusion of otitis media with effusion (OME) has suggested the possibility that bacterial endotoxin may be involved in the pathogenesis and development of OME. In this study, we investigated the direct effects of lipopolysaccharide (LPS), possessing the major part of endotoxin activity, on the ciliary activity in the tubotympanum. The study shows that LPS deteriorates ciliary activity in a dose-response fashion and that even low levels can, with extended exposure, cause dysfunction of cilia. It can be postulated that endotoxin in middle ear effusions aggravates the condition of mucociliary dysfunction thus leading to chronic OME.
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PMID:Effects of bacterial endotoxin on ciliary activity in the tubotympanum. 328 76

In the present study, we have examined the hitherto unknown effects of long-term exposure to lipopolysaccharide (LPS), possessing the major parts of biological activity of endotoxin, on ciliary activity in the middle ear. Our results show that LPS can affect the ciliary activity in a dose-response fashion: 1) LPS does not impair the ciliary activity up to 168 h if the concentration is 1 ng/ml or less; 2) 10 ng/ml of LPS does not impair ciliary activity in the middle ear close to the tympanic orifice up to 168 h, but can cause reduced activity distal to the orifice after extended exposure (more than 96 h); 3) 100 ng/ml or more of LPS can cause dysfunction of cilia in the tympanic cavity, and in particular 1 microgram/ml or more of LPS can quickly disable the ciliary activity in the middle ear distal to the orifice.
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PMID:Effects of bacterial endotoxin on the ciliary activity in the in vitro middle ear mucosa. 343 72

Otitis media with effusion was induced in guinea pigs by intratympanic instillation of lipid A, the lipid moiety of gram-negative bacterial lipopolysaccharide from Salmonella minnesota Re595. Lipid A was chosen as an inducer because of its similar composition among various bacterial species. Animals were killed from the first to 14th day after instillation of various concentrations (0.2, 2, 20, 200 micrograms/ml) of lipid A in 0.5% triethylamine. By 3 days after instillation, all experimental animals developed serous middle ear effusion. The histologic findings included hemorrhage, mucosal edema, capillary engorgement, and migration of infiltrative cells including macrophages, polymorphonuclear neutrophils, and lymphocytes. These findings were most prominent 3 days after instillation, and the recovery of the middle ear epithelium was observed within 14 days. Repeated instillation of lipid A (2 micrograms/ml) at an interval of 14 days reinforced the local response accompanied by serous middle ear effusion. These findings indicate that lipid A can induce the inflammatory changes with middle ear effusion and that lipid A plays an important role in the pathogenesis of otitis media with effusion.
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PMID:Experimental otitis media with effusion induced by intratympanic lipid A instillation. 357 74


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