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Biomedical subjects

D J Lim

Publications and source records attributed to D J Lim.

190 records · Page 11Linked to original sources
PubMedDate not supplied

Effect of formalin-fixed Hemophilus influenzae and Streptococcus pneumoniae on dye transport by the chinchilla eustachian tube.

An in situ method for measuring the ability of the middle ear and eustachian tube ciliated epithelium to transport dye to the nasopharynx was used to assess the role endotoxin-containing killed bacteria have on the development of otitis media with effusion. In addition, electron microscopy was used to monitor histological changes induced by exposure to these organisms and the ability of the mucosa to recover. The results indicated that exposure to a killed gram-negative but not a gram-positive otitis media pathogen leads to early production of middle ear fluid, evidence of capillary leakage and significant slowing of mucociliary transport. The damage was, however, reversible with the epithelium returning to normal both functionally and histologically within 7 days of exposure.

Animals↗
PubMedDate not supplied

Structural organization of the outer hair cell wall.

The lateral wall of the mammalian outer hair cell has specialized structures composed of "subplasma lamina" and "micropillars." These structures anchor the subsurface cisternae to the inner leaflet of the cell membrane. The micropillars are arranged in parallel arrays encircling the entire inner side of the outer hair cell. The subplasma lamina appears sheet-like with rows of indentations and ridges in parallel arrays or in grid patterns among the specimens prepared for scanning electron microscopy. It is interpreted that these indentations are formed by the loss of the micropillars due to the osmium digestion. It is suggested that the subplasma lamina and micropillars may provide a rigid structure of the cylindrical shape and also may be involved in the motile activity of the outer hair cell.

Animals↗
PubMedDate not supplied

Distribution of glycoconjugates during cochlea development. A histochemical study.

Specific occurrence and distribution of glycoconjugates in the developing mouse cochlea was investigated using Alcian blue/PAS staining. The AB/PAS positive staining occurred intracellularly, extracellularly, pericellularly, and as glycocalyx. Pericellular staining occurred between certain epithelial cells in early stages of development, and extracellular deposit occurred mostly in mesenchymal tissue surrounding the cochlear duct and later in developing spiral ligament. During early stages of development, mesenchymal tissue and pericellular space of different epithelial cells of the cochlear duct were intensely stained, suggesting that these glycoconjugates may play an important role in the differentiation of the cochlear structures. Different supporting cells (e.g. Deiters' cells, pillar cells) were intensely stained at different development stages coinciding with the time when the subcomponents of the tectorial membrane (TM) were being formed. This finding suggests that glycoconjugates in the TM are produced by these cells.

Alcian Blue↗
PubMedDate not supplied

Immunobarriers of the tubotympanum.

The tubotympanum is protected by an immune system in addition to the mucociliary, secretory (antibacterial substance), and phagocytic defense systems. The immune protection is provided by innate and adaptive immune systems. With the latter, the tubotympanum is protected by both the local (humoral and cellular) and the systemic immunity. The major immunoglobulins involved are IgG, IgM (SIgM), and SIgA, although IgE and IgD may also be involved.

Ear, Middle↗
PubMedDate not supplied

Experimental otitis media in chinchillas. I. Baseline immunological investigation.

Baseline immunological data on the chinchilla were obtained, and a detailed method for purification of each immunoglobulin is described. Antiserum to each chinchilla immunoglobulin was made by immunizing rabbits with immunoglobulins purified from serum and colostrum. The main classes of serum immunoglobulins in the chinchilla are G, A, and M, similar to those in other rodents and humans. The immunohistochemical study showed that the distribution of immunocytes in lymphoid organs is similar to that of other rodents and humans. In the eustachian tube the glandular acinar cells were distinctly positive for IgA staining. A few IgA-forming cells and very rare IgG- and IgM-forming cells were found in the eustachian tube mucosa, but all were very rare in the middle ear mucosa. These findings suggest that the secretory immune system of the chinchilla eustachian tube may be active in the normal state and that the local immune system of the normal middle ear mucosa may be latent but could become active following antigenic stimulation.

Animals↗
PubMedDate not supplied

Experimental otitis media in chinchillas. II. Comparison of the middle ear immune responses to S pneumoniae types 3 and 23.

The present study shows that two different serotypes of Streptococus pneumoniae (type 3 and 23) when inoculated through the bulla elicit distinctly different immune responses in chinchillas. The passive hemagglutination assay shows that type 3 is a better immunogen than type 23 and that type 3 primarily elicits immune responses in the middle ear. When class-specific antibody activity was measured with the red cell linked antigen-antibody reaction test, antibody activities of serum IgG to type 3 slightly declined and of effusion IgM and IgA to type 3 increased following type 3 infection, whereas following type 23 infection antibody activities of serum IgG to type 23 increased and no antibody activities of IgA and IgM to type 23 were present in the effusions.

Animals↗
PubMedDate not supplied

Effect of spermatocele fluid on growth of human prostatic cells in culture.

The present study was carried out to investigate whether testicular fluid derived from a spermatocele contains substance(s) that promote the growth of human prostatic cells in culture. Human spermatocele fluid was centrifuged to sediment spermatozoa. The supernatant was then added to cultures of human prostatic stromal or epithelial cells that were isolated from surgical specimens of benign prostatic hyperplasia. Addition of spermatocele fluid in quantities of 1 microgram/ml of protein resulted in a significant increase in the number of both prostatic stromal and epithelial cells at the end of a 6-day culture period. Human serum at equivalent protein concentrations in the culture medium had no stimulatory effect. At least two separate growth-promoting factors were found in spermatocele fluid, one for stromal cells and one for epithelial cells. The mitogen for stromal cells was heat labile and persisted after treatment with activated charcoal. The factor for epithelial cells was heat stable but was removed by charcoal treatment. These observations are consistent with the concept that the human testis secretes nonandrogenic substances that can promote prostatic growth.

Cell Division↗
PubMedDate not supplied

A bacterial sensitivity test to determine the effectiveness of minocycline HCI (Minocin), erythromycin (Erythrocin) and ampicillin (Ampicin) on the predominant microorganisms present in a diseased periodontium.

The purpose of this study was to determine the effectiveness of the three antimicrobials--Minocycline HCI, Erythromycin and Ampicillin based on the percentage reduction of bacteria present in subgingival microflora and in vitro assessment of antibiotic susceptibility of cultured strains of predominant microorganisms present in a diseased periodontium. Twelve volunteers 18 to 65 years of age, with moderate to severe periodontal disease, were randomly divided into Group A and Group B of 6 members each. Oral lavage procedure was performed to Group A and Group B received systemic administration of antibiotic for five days. Patients 1 & 2, 3 & 4 and 5 & 6 received minocycline HCI, Erythromycin and Ampicillin respectively. Microbiologic samples in the subgingival crevicular area in selected tooth exhibiting clinical periodontal breakdown were obtained from all the subjects prior to and after the oral lavage procedure and systemic drug administration. Streptococcus viridans is the most predominant aerobic microorganism obtained from 83% of samples. However no anaerobic microorganism has been isolated. Bacterial sensitivity testing showed 60% of samples with positive growth of microorganisms (S. viridans) were also equally sensitive to Minocycline HCI, Erythromycin and Ampicillin. Oral lavage proved to be ineffective in reducing the number of bacteria. However, systemic drug administration revealed that there was a reduction in bacterial count after taking such antibiotics for five days which is more favorable to Minocycline HCI.

Adolescent↗