Pathogenicity of Cilia-associated Respiratory (CAR) Bacillus Isolates for F344, LEW, and SD Rats

1997 ◽  
Vol 34 (4) ◽  
pp. 263-270 ◽  
Author(s):  
T. R. Schoeb ◽  
M. K. Davidson ◽  
J. K. Davis
Keyword(s):  
Middle Ear ◽  
Mycoplasma Pulmonis ◽  
Sd Rats ◽  
Colony Forming Units ◽  
Affect Expression ◽  
Sterile Medium ◽  
Nasal Passages

We conducted experiments to test whether rats of F344, LEW, and SD strains differ in susceptibility to mycoplasma-free isolates of cilia-associated respiratory (CAR) bacillus, whether Mycoplasma pulmonis can affect expression of CAR bacillus disease, and whether isolates of CAR bacillus differ in virulence for rats. In the first experiment, 24 rats of each strain were inoculated intranasally with 107 bacilli of CAR bacillus X1428D/AS, and 24 rats of each strain were inoculated with sterile medium (controls). Eight weeks later, eight inoculated rats and eight control rats of each strain were euthanatized, eight inoculated and eight control rats were given 106.5 colony-forming units of M. pulmonis X1428D, and eight inoculated rats and eight control rats were sham inoculated. Four rats of each group were euthanatized 4 or 8 weeks after the second inoculation. Severity of lesions in nasal passages, middle ear, trachea, and lungs was assessed by scoring. Rats of all three strains given CAR bacillus had typical lesions of similar severity; M. pulmonis X1428D was avirulent and did not exacerbate CAR bacillus disease. In the second experiment, groups of eight rats of F344 and SD strains were given 105 or 107 CAR bacillus X1328E, X1428D/AS, or X2450D and euthanatized 8 or 16 weeks later. Isolates X1428D/AS and X2450D caused similar lesions in rats of both strains and at both doses, but CAR bacillus X1328E was avirulent. Rats of the tested strains are similarly susceptible to CAR bacillus disease, but CAR bacillus isolates differ in virulence.

Exacerbation of Murine Respiratory Mycoplasmosis by Sialodacryoadenitis Virus Infection in Gnotobiotic F344 Rats

1987 ◽  
Vol 24 (5) ◽  
pp. 392-399 ◽  
Author(s):  
T. R. Schoeb ◽  
J. R. Lindsey
Keyword(s):  
Virus Infection ◽  
Culture Medium ◽  
Lung Lesion ◽  
Mycoplasma Pulmonis ◽  
Experimental Conditions ◽  
Sterile Culture ◽  
Naturally Occurring ◽  
Colony Forming Units ◽  
Nasal Passages ◽  
F344 Rats

To test the hypothesis that sialodacryoadenitis virus infection could exacerbate respiratory mycoplasmosis in rats, four groups of 40 7- to 9-week-old gnotobiotic F344/N rats were given two intranasal inoculations 7 days apart: Mycoplasma pulmonis, then sialodacryoadenitis virus; M. pulmonis followed by sterile culture medium; medium initially, then virus; or two doses of medium. Immediately and 3, 5, 10, and 20 days after the second inoculation, the nasal passages, middle ears, larynges, tracheas, lungs, and salivary and lacrimal glands of four rats from each group were prepared for histologic examination, and the respiratory organs from four other rats were collected for quantitative culture of M. pulmonis and sialodacryoadenitis virus. To test statistically the effect of virus infection on mycoplasmosis lesions, we determined indices of the severity of respiratory tract lesions by subjective scoring. In rats given both organisms, indices of nasal and tracheal lesions were significantly ( P < 0.05) greater at 3 days and after than in rats given M. pulmonis alone, and middle ear, laryngeal, and lung lesion indices were significantly greater at 5 days and after. Rats given both mycoplasma and virus had significantly more mycoplasmal colony-forming units in the nasal passages at 3 days and after, and in the larynges, tracheas, and lungs at 10 and 20 days, than rats given only mycoplasma. These results show that sialodacryoadenitis virus infection can exacerbate respiratory mycoplasmosis in rats under experimental conditions; therefore, the virus probably also contributes to expression of naturally occurring mycoplasmosis.

Pseudomonas Otitis Media after Eustachian Tube Obstruction

1992 ◽  
Vol 107 (4) ◽  
pp. 511-515 ◽  
Author(s):  
Patrick J. Antonelli ◽  
Steven K. Juhn ◽  
Marcos V. Goycoolea ◽  
G. Scott Giebink
Keyword(s):  
Otitis Media ◽  
Eustachian Tube ◽  
Middle Ear ◽  
Otitis Media With Effusion ◽  
Acute Otitis Media ◽  
Suppurative Otitis Media ◽  
Tube Obstruction ◽  
Colony Forming Units ◽  
Tube Function ◽  
Pseudomonas Infection

Previous experiments have shown that Pseudomonas aeruginosa may infect the middle ears of chinchillas by way of the eustachian tube and that chinchillas with acute otitis media (AOM) are more susceptible to pseudomonas infection than animals without AOM. The purpose of this experiment was to examine the effects of otitis media with effusion (OME), induced by means of eustachian tube obstruction, on middle ear susceptibility to nasal inoculation of P. aeruginosa. Chinchilla eustachian tubes were obstructed with silicone rubber sponge bilaterally; OME developed in eight animals (11 ears)—three bilaterally and five unilaterally—and persisted for 6 months. Ten chinchillas with normal eustachian tube function served as controls. All animals were nasally inoculated with 5 times 104 colony-forming units of P. aeruginosa. Pseudomonas otitis media developed in eight of 11 OME ears with effusion, none of five ears without OME, and four of 20 control ears (X2 = 11.782, p = 0.003). Therefore, P. aeruginosa can infect the middle ear by way of the eustachian tube. Tubal dysfunction may lead to the development of chronic suppurative otitis media by increasing tubotympanic susceptibility to opportunistic pathogens.

An Animal Model of Acute Otitis Media Consequent to β-Lactamase-Producing Nontypable Haemophilus Influenzae

1982 ◽  
Vol 90 (6) ◽  
pp. 831-836 ◽  
Author(s):  
William J. Doyle ◽  
John S. Supance ◽  
Gabriel Marshak ◽  
Erdem I. Cantekin ◽  
Charles D. Bluestone ◽  
...  
Keyword(s):  
Animal Model ◽  
Haemophilus Influenzae ◽  
Otitis Media ◽  
Middle Ear ◽  
Otitis Media With Effusion ◽  
Acute Otitis Media ◽  
Protective Mechanism ◽  
Colony Forming Units ◽  
Direct Inoculation ◽  
The Right

A chinchilla model of acute otitis media with effusion consequent to β-lactamase-producing nontypable Haemophilus influenzae was developed using the method of direct inoculation of 145 colony-forming units (CFU) or 252 CFU of β-lactamase—producing nontypable H influenzae into the right superior bullae of 40 chinchillas. The course of the disease was documented longitudinally by otomicroscopy, tympanometry, and periodic culturing of the middle ears. Onset of the disease occurred in 100% of the animals between two and six days postinoculation and resolution was complete in all ears by day 36. Results of rechallenge with the same organism support the combined effect of a local and weaker systemic middle ear protective mechanism rendering resistance to reinfection with a homologous organism in the chinchilla.

Murine Respiratory Mycoplasmosis in LEW and F344 Rats: Strain Differences in Lesion Severity

1982 ◽  
Vol 19 (3) ◽  
pp. 280-293 ◽  
Author(s):  
J. K. Davis ◽  
G. H. Cassell
Keyword(s):  
Strain Differences ◽  
Inflammatory Cells ◽  
Lymphoid Cells ◽  
Model Systems ◽  
Mycoplasma Pulmonis ◽  
Weanling Rats ◽  
Colony Forming Units ◽  
Gross Lesions ◽  
F344 Rats

Pathogen-free weanling rats of the LEW and F344 strains were caged together for two months to eliminate microbial and environmental differences, and then infected intranasally with 10-fold dilutions of viable Mycoplasma pulmonis. At necropsy 28 days postinoculation, F344 rats had no gross lung lesions, even those given the maximum dose of 1.4 X 109 colony-forming units of M. pulmonis. LEW rats often had extensive gross lesions with a gross-pneumonia-dose50 of 1.1 X 107 colony-forming units/rat. Histological examination of the respiratory tract (nasal passages, larynges, tracheae, and lungs) and tympanic cavities showed both qualitative and quantitative differences in lesions between the two strains, particularly in the lungs. Hyperplasia of bronchus-associated lymphoid tissue occurred in both strains, but was more extensive in LEW rats. Atelectasis, alveolar consolidation (due primarily to mononuclear inflammatory cells), and suppurative bronchitis and bronchiolitis were seen only in LEW rats. Infiltrates of lymphoid cells into the lungs distal to bronchi and around blood vessels also were seen primarily in LEW rats. These differences between the two rat strains provide excellent model systems with which to dissect the role of cell responses in the pathogenesis of a naturally occurring chronic lung disease.

Dispersal ofBacillus thuringiensisvar.kurstakiin an experimental cabbage field

1995 ◽  
Vol 41 (2) ◽  
pp. 118-125 ◽  
Author(s):  
Jens Christian Pedersen ◽  
Bjarne Munk Hansen ◽  
Per Hyldebrink Damgaard ◽  
Jørgen Eilenberg
Keyword(s):  
Population Dynamics ◽  
Bacillus Thuringiensis ◽  
Half Life ◽  
Pieris Brassicae ◽  
Carabid Beetles ◽  
Colony Forming Units ◽  
Sterile Medium ◽  
Surface Active ◽  
Rain Splash

The field population dynamics of Bacillus thuringiensis var. kurstaki DMU67R isolated from cabbage leaves was investigated. Two experimental cabbage plots were spray inoculated with a suspension of sporulated bacteria containing 6.5 × 107colony-forming units (cfu)/mL DMU67R or with a sterile medium control. To study transport between phyllosphere and soil, plastic covering was used during spraying to ensure that DMU67R was applied only on leaves (8.5 × 106cfu/g) or on soil (1.2 × 104cfu/g). Numbers of DMU67R declined five log units during the first 4 weeks after spraying of leaves; the initial half-life (1st week) was 16 h. In topsoil, however, a long-term persistency was demonstrated with a half-life exceeding 100 days. Dispersal by rain splash from topsoil to lower leaves of cabbage was demonstrated. After 1 year, analysis of the top 15 cm of soil showed that 77% of DMU67R remained in the 0- to 2-cm topsoil layer. When DMU67R was applied on leaves, larvae of Pieris brassicae were killed within 7 days after spraying. Germination of DMU67R was demonstrated in dead P. brassicae larvae but not in any leaf or soil sample. Pitfall sampling demonstrated dispersal of DMU67R by means of carabid beetles (up to 135 m) and other surface-active insects carrying 102–103 cfu/g wet mass.Key words: Bacillus thuringiensis, Pieris brassicae, cabbage, soil, dispersal, population dynamics.

The Effect of Stapedectomy on the Loudness of One’s Own Voice

1965 ◽  
Vol 8 (3) ◽  
pp. 223-234 ◽  
Author(s):  
William Melnick
Keyword(s):  
Middle Ear ◽  
Normal Subjects ◽  
Sound Energy ◽  
Loudness Function ◽  
Before And After ◽  
Increased Sensitivity

Five subjects with normal middle ear mechanisms, and otosclerotic patients, before and after stapedectomy, matched the loudness of their voices to the loudness of a 125-cps-sawtooth noise. The results showed loudness matching functions with gradual slopes, less than 1.00, for the normal subjects and the patients prior to stapedectomy. Post-surgically, the loudness function for the patients increased in steepness to considerably more than 1.00. These results are explained, most logically, in terms of increased sensitivity of the altered middle ear to sound energy generated by the listener’s own voice.

Are mucin genes yet to be cloned expressed by human middle ear mucosa?

1998 ◽  
Vol 23 (3) ◽  
pp. 265-265 ◽  
Author(s):  
Hutton ◽  
Birchall ◽  
French ◽  
Kubba ◽  
Severn ◽  
...  
Keyword(s):  
Middle Ear ◽  
Middle Ear Mucosa ◽  
Mucin Genes ◽  
Human Middle Ear
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