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Biomedical subjects

D B Webster

Publications and source records attributed to D B Webster.

62 records · Page 4Linked to original sources
PubMedDate not supplied

Reversible conductive hearing loss in mice.

Fibrin tissue adhesive was injected into the right ears of four 7-week-old CBA/J mice. Auditory brain stem responses (ABRs) were used to monitor changes in auditory sensitivity over the next 26 days, after which the middle ears and cochleas were examined histologically. Mean maximum ABR threshold shifts were as great as 36 dB, and were larger for higher frequencies than for lower. Maximum shifts occurred between 1 and 8 days; by 26 days, thresholds had returned to intensity levels observed before injection.

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PubMedDate not supplied

Cochlear nerve projections following organ of corti destruction.

Experimental organ of Corti destruction results in (1) secondary loss of all type I spiral ganglion neurons, (2) development of type III spiral ganglion neurons, (3) degeneration of most cochlear nerve myelinated fibers, and (4) terminal degeneration in the ventral and dorsal cochlear nuclei. The first signs of degenerative changes occur by eight days after organ of Corti destruction and degeneration debris remains until 28 weeks after destruction.

Animals↗
PubMedDate not supplied

Incomplete maturation of brainstem auditory nuclei in genetically induced early postnatal cochlear degeneration.

In the Shaker-2 mouse mutant, a cochleo-saccular type of genetically induced inner ear degeneration occurs. Morphological signs of degeneration are evident in the 3rd postnatal week and a severe and almost total degeneration has occurred by the age of 6-9 weeks. There are no qualitative differences between the brain of the normal CBA/J mouse and that of the Shaker-2 mouse. The growth of the auditory brainstem nuclei (dorsal cochlear nucleus and ventral cochlear nucleus) in the mutant Sh-2 mouse has stopped by 14 days of age--but not in the normal CBA/J mouse. The brainstem as a whole continues to grow between 14 and 140 days of age in both strains. The early cochlear degeneration coincides with the critical period when a normal input from the peripheral receptor organ is necessary for the maturation of the central auditory pathway.

Animals↗
PubMedDate not supplied

IgA deficiency in juvenile chronic polyarthritis.

Immunoglobulins measured sequentially in 582 juvenile chronic polyarthritis patients revealed 12 with persistently absent IgA and 15 consistently below 20 mg/dl. There was an increased presentation with pauciarticular onset but systemic disease was the same as in the whole group. Follow-up showed that 9 of the 12 without IgA developed polyarthritis as have 11 of the 15 with low IgA; in contrast to previous studies, the disease has been severe in at least half of the patients.

Adolescent↗