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Biomedical subjects

D J Lim

Publications and source records attributed to D J Lim.

At least 109 records · Page 6Linked to original sources
PubMed1983

The behavior and vestibular nuclear morphology of otoconia-deficient pallid mutant mice.

Pallid mutant mice with no otoconia in their gravity receptors were behaviorally tested and their vestibular nuclei measured to determine if this developmental sensory deprivation had any detrimental effect on central vestibular structure and function. This absence of otoconia was correlated with disorientation in water and absence of air righting reflexes. The inferior and superior vestibular nuclei were smaller than normal, but neurons within regions that receive direct gravity receptor input were smaller only unilaterally in medial vestibular nucleus. It was tentatively concluded that the sensory deprivation resulting from reduced gravity receptor input was responsible for the behavioral and central morphological abnormalities.

Animals↗
PubMed1982

Immunologic study on the inner ear. Immunoglobulins in perilymph.

The immunoglobulin composition of perilymph (PL) was measured using electroimmunodiffusion, and transfer of serum antibodies to PL was studied using a passive hemagglutination test in chinchillas and guinea pigs. The mean values of IgG an albumin in PL were two to four times greater than those in CSF. In guinea pigs, IgA was found in 93% of the PL and 32% of the CSF samples, but in chinchillas only trace amounts of IgA were found in 50% of the PL and 15% of the CSF samples. No IgM was detected in PL or CSF of either species. This study suggests that a greater portion of the immunoglobulins in PL probably is derived from perilymphatic blood vessels as a filtrate and that the perilymphatic inner ear immune system is independent from that of the CSF.

Animals↗
PubMed1982

Panel discussion: pathogenesis of otitis media. Bacteriology and immunology.

Three features of otitis media with effusion (OME) are important in understanding its pathogenesis: 1. it is most common among children, when the eustachian tube is poorly developed; 2. it is most common during the winter months, when the common cold is prevalent; and 3. bacteria are found in a large number of middle ear effusions from OME patients. Although middle ear effusions are conventionally thought to be sterile, numerous recent investigations favor a bacterial pathogenesis of OME. Four possibilities can be considered: 1. bacteria are modified by antibiotics or antibodies, causing a lingering inflammation; 2. early antibiotic treatment may interfere with the development of local immunity; 3. bacterial antigen trapped in the middle ear causes immune injury leading to OME; and 4. bacterial endotoxin and inflammatory mediators cause middle ear effusions.

Animals↗
PubMed1980

Cochlear anatomy related to cochlear micromechanics. A review.

The sensory cilia of the mammalian cochlea show an orderly gradation in height along the length of the cochlea. The cilia are taller in the apex and shorter in the base. Differences in ciliary gradation also exist between the different rows of outer hair cell cilia along the length of the cochlea. There are gradations in width and thickness in the moveable portion of the tectorial membrane paralleling those in the basilar membrane. There are also gradations in the relationship between the tectorial membrane and the slope of the reticular lamina along the length of the cochlea. This suggests that there may be additional mechanical fine-tuning capability built into the organ of Corti besides the basilar membrane. The tectorial membrane is firmly attached to the outer hair cell cilia along the entire length of the cochlea in all species examined. The inner hair cell cilia do not have the same firm attachment to the tectorial membrane as outer hair cell cilia. This suggests that the modes of mechanical coupling between the tectorial membrane and the inner and outer hair cell cilia are different.

Animals↗
PubMed1979

Otitis media with effusion. Cytological and microbiological correlates.

A quantitative cytologic study of 83 middle ear effusions from children with otitis media with effusion (OME) was made with the use of cytocentrifuge-prepared smears and was correlated with bacteriological findings. The identification of the types of cell present in an effusion was confirmed by electron microscopic findings. The most common cell types were neutrophilic leukocytes, lymphocytes, and macrophages, but a few eosinophils were found in only one case. The cytologic profile of an effusion correlated well with the bacterial culture results. Neutrophil counts were significantly higher in effusions that contained pathogenic bacteria (P less than .01) than in culture-negative effusions. Lymphocytes were the dominant cell type in culture-negative effusions. The results support the idea that bacteria are involved in the pathogenesis of many cases of OME.

Cell Count↗
PubMed1975

Chronic middle ear effusions. Immunochemical and bacteriological investigations.

Middle ear effusions from 100 patients (ages 6 months to 10 years) with serous otitis media were examined. The IgA, IgG, and lysozyme were demonstrated at a higher level in the effusions than the corresponding sera, indicating local production. The mucoid type contained higher level of immunoglobulins and lysozyme compared to serous type effusions. Bacteria were found in 77 percent of the effusions by means of a smear, and 52 percent yielded positive bacterial culture. The incidence of positive culture in effusions of the patients less than 6 years of age was 60 percent, while the group older than 6 years old was 32%, and the group over 8 was only 22 percent. Bacterial recovery rate was inversely related to the dramatic increase with age of IgA and IgG and lysozyme levels in effusions.

Age Factors↗
PubMed1975

Surface-active agent in Eustachian Tube Function.

Using 15 fresh guinea pig temporal bones, Eustachian tubal function was tested repeatedly before and after saline washing to demonstrate the effect of surface-active agent. Although tubal opening pressures for the 15 ears varied considerably, in each ear tested, a higher pressure was required to open the Eustachian tube after saline washing (P less than .001). A significant statistical difference in Eustachian tube opening pressure was also found between consecutive trials before washing the Eustachian tube with saline (P less than .001). This phenomenon disappeared after saline washing. It is possible that these phenomena occurred as a result of surface-active agent (surfactant) functioning in the Eustachian tube.

Air Pressure↗
PubMed1975

Trisomy 18. A temporal bone report.

Since Edwards first described the trisomy 17-18 syndrome in 1960, the findings in the temporal bones of only four patients with this condition have been reported. They varied widely, ranging from a normal temporal bone, to severe malformations of both the middle and inner ear structures. This study describes the temporal bone findings in a patient with this syndrome. Many of the abnormalities described previously were present as well as the following unreported findings: complete bony atresia of the external canal, an aberrant tensor tympani muscle that did not insert into the malleus but rather attached to a dehiscent area in the Fallopian canal, wide short utricular and saccular ducts, and a widely patent cochlear aqueduct. There was also a developmental arrest of the membranous structures within the cochlea that probably occurred during the 12th week of fetal life.

Autopsy↗