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D J Lim

Publications and source records attributed to D J Lim.

At least 55 records · Page 3Linked to original sources
PubMed1994

Effect of endotoxin on cultured rat middle ear epithelium, rat meatal epidermis, and human keratinocytes.

Several factors seem to contribute to the series of events in the pathogenesis of otitis media and cholesteatoma. Endotoxin is likely to be one of these factors, since it has been found in human middle ear effusions and since injection of this substance into the middle ear, in animal experiments, gave rise to prominent reactions. Provoking of epithelial cells in vitro with endotoxin led to distinct cell responses that might be associated with cholesteatoma formation. In this study the effect of endotoxin on serially cultured rat middle ear epithelium, rat meatal epidermis, and human keratinocytes was investigated. Endotoxin strongly stimulated the proliferation of middle ear epithelium and human keratinocytes and inhibited that of meatal epidermis. Furthermore, endotoxin affected the morphology of the three types of tissue. Rat middle ear epithelium revealed epithelial cell tracks with interconnecting bridge-like structures protruding above the culture plane, whereas rat meatal epidermis showed increased terminal differentiation expressing large areas of blister-like structures detaching from the culture dish. Cross-linked envelope analysis of human keratinocytes showed an increased terminal differentiation that was morphologically confirmed but was not confirmed by cytokeratin analysis. The results of this study support the hypothesis that endotoxin may play an important role in the pathogenesis of otitis media and cholesteatoma.

Animals↗
PubMed1993

Ubiquitous presence of chromogranin A in the inner ear of guinea pig.

Chromogranin A (CGA), which is supposed to be responsible for the calcium storage of secretory vesicles and is also considered to be a marker protein of neurons and endocrine cells, has been found in a variety of organs and tissues. In the present study, soluble proteins from the organ of Corti, saccule, crista, utricle, tectorial membrane, stria vascularis, and the spiral ligament from the inner ear of guinea pig were extracted, and probed with both polyclonal and monoclonal CGA antibodies to determine the presence of CGA. A 75 kDa protein reactive to both antibodies was found in the organ of Corti, saccule, crista, utricle, stria vascularis, and the spiral ligament, suggesting the widespread presence of CGA in the inner ear.

Animals↗
PubMed1993

Growth of an androgen-sensitive human prostate cancer cell line, LNCaP, in nude mice.

This study was undertaken to establish an androgen-sensitive model of human prostatic carcinoma in nude mice. The androgen-sensitive prostatic carcinoma cell line, LNCaP, was suspended in reconstituted basement membrane (Matrigel) and injected subcutaneously into nude mice. The LNCaP cell line was chosen for the study, because the cell line is androgen-sensitive and secretes prostate specific antigen (PSA) into culture media. Following injection of 1 x 10(6) LNCaP cells with 0.25 ml of Matrigel, 88% of mice exhibited palpable tumor burdens after 12 weeks of observation. In addition, significant levels of PSA were observed in the serum of LNCaP-bearing mice. Bilateral orchiectomy of mice resulted in tumor regression and stabilization of serum PSA levels, compared to testis-intact controls. A significant correlation of PSA to tumor volume and weight was observed. The castrate level of testosterone was confirmed by radioimmunoassay and was similar to testosterone levels in female nude mice. Matrigel allows for a conducive environment to propagate LNCaP cells in nude mice. Furthermore, the growth can be manipulated by castration, leading to involution of tumor and stabilization of serum PSA level. This in vivo model of hormone-sensitive human prostate cancer cell line will serve as a model for the study of prostate tumor biology and treatment.

Animals↗
PubMed1993

Computerized tomography in the preoperative staging for pulmonary metastases in patients with renal cell carcinoma.

Computerized tomography (CT) is the state of the art technology for pulmonary staging of many extrathoracic malignancies. From 1976 to 1990, 120 of 330 patients with renal cell carcinoma treated at our hospital underwent chest radiography and chest CT. These patients were reviewed to evaluate the role of CT in examining the chest for staging of renal cell carcinoma. Median followup was 24 months. Agreement between the 2 imaging modalities was found in 105 patients. The results of chest radiography and chest CT were normal in 82 and abnormal in 23 patients. Of the 15 patients with disagreement between the 2 studies 13 had normal chest radiography with abnormal chest CT and 2 had abnormal chest radiography with normal chest CT. The 13 patients with normal chest radiography and abnormal CT were further divided into 2 groups: 8 patients with small borderline lesions seen on CT only and 5 patients with evidence of advanced, bulky disease outside the chest at presentation. A substantial agreement, more than chance alone, between chest radiography and CT existed (p < 0.0001). Followup records and survival data have shown no significant impact as a result of the disagreement between the 2 imaging modalities on the treatment decision or ultimate outcome. Based on this information, we believe that in patients with a relatively small tumor (stage T1) a normal chest radiograph suffices for pulmonary staging. The indications for additional chest CT would include solitary nodule on chest radiograph before salvage resection of metastasis, chest symptoms suggestive of endobronchial metastasis or extensive regional disease.

Aged↗
PubMed1993

Pyelovenous lymphatic migration of transitional cell carcinoma following flexible ureterorenoscopy.

Ureterorenoscopy has enhanced the diagnosis and treatment of upper urinary tract disorders. However, the irrigation necessary for visualization and distention of the lumen may increase renal pelvic pressure, resulting in pyelovenous lymphatic backflow. We report a case of renal pelvic transitional cell carcinoma that may have migrated to submucosal venous and lymphatic spaces during flexible ureterorenoscopy.

Aged↗
PubMed1993

Multilocular prostatic cystadenoma presenting as a large complex pelvic cystic mass.

Symptomatic prostatic cysts are not common. We report a case of a large complex cystic pelvic mass encountered in a Jordanian man that proved to be a huge midline prostatic cyst with seminal vesicle contained within the wall. This finding represents a variation of the newly proposed diagnosis, multilocular prostatic cystadenoma.

Cystadenoma↗
PubMed1993

Modeling adenovirus type 1-induced otitis media in the chinchilla: effect on ciliary activity and fluid transport function of eustachian tube mucosal epithelium.

Previous studies have shown that viral upper respiratory tract (URT) infection predisposes to the development of bacterial otitis media (OM). The mechanisms underlying this phenomenon have been well defined for influenza A virus in the chinchilla model of experimental OM but have not been for adenovirus because of the heretofore lack of an appropriate model. In this study, chinchillas were inoculated intranasally or transbullarly with type 1 adenovirus to assess whether or not the chinchilla could serve as a suitable model for future investigation of adenovirus predisposition to bacterial OM. Data indicated that the chinchilla readily supported an active infection by and responded serologically to this agent and that route of inoculation markedly influenced otoscopic findings, elicitation of middle ear fluids, onset and location of histopathology, and progression of disease. The time course of disease onset and recovery and an assessment of the effect of this virus isolate on the mucosal epithelial integrity and on both the ciliary activity and transport function of the eustachian tube epithelium for both routes of inoculation are presented.

Adenoviridae Infections↗
PubMed1993

Development of secretory elements in murine tubotympanum: lysozyme and lactoferrin immunohistochemistry.

Secretory activity, particularly of antibacterial agents such as lysozyme and lactoferrin, is an important aspect of the mucosal defense mechanism, and the development of these agents may have a direct bearing on the susceptibility of the ear to infection. In this study, the secretory cells of the murine tubal epithelium were first observed at gestational day 17. Although tubal glands began to develop on gestational day 18, their secretory activity was first shown on postnatal day 3. The number of secretory cells of the tubal epithelium increased rapidly immediately after birth, while that of the tubal glands showed a gradual increase from postnatal day 3. The epithelial secretory cells in the tubotympanum matured at birth, but the tubal glands matured gradually after birth. Lysozyme was first recognized in the epithelial secretory cells on postnatal day 1, while lactoferrin was first detected in the tubal glands on postnatal day 3. Both lysozyme and lactoferrin were co-localized in the serous cells of the tubal glands. The secretion of lysozyme and lactoferrin seemed to reflect the maturation of the secretory cells in the murine tubotympanum.

Alcian Blue↗
PubMed1993

Effect of influenza A virus on ciliary activity and dye transport function in the chinchilla eustachian tube.

Previous studies have shown that influenza A virus inoculated via a transbullar approach can cause severe disorders of the chinchilla eustachian tube. In this study, we inoculated chinchillas both intranasally and transbullarly with influenza A virus (A/Alaska/6/77) to assess the effect of this virus on both the ciliary activity of eustachian tube epithelium and eustachian tube transport function. Data indicated that while the nature of the major lesions was indistinguishable, the differing routes of inoculation did influence the time course and initial location of virus-induced histopathology. Analysis of ciliary beat frequency and dye transport function indicated a maximal decrease approximately 7 to 14 days postinoculation, with return to normal function by 28 days postinoculation. Light and transmission electron microscopic observations of the evolution of histopathology and return to normal histology correlated well with functional assessment data.

Administration, Intranasal↗
PubMed1993

Culture of middle ear epithelium: a review.

We discuss several techniques of culturing middle ear epithelium from several species, which was formerly difficult but is now possible because of recent advances in culture methods. The three main methods of initiating a culture are organ culture, primary explant culture, and cell culture. Although each method has both advantages and disadvantages, investigators can choose the method most suitable to their purpose. A few researchers, including ourselves, have succeeded in obtaining serial culture of middle ear epithelium. Using 3T3 feeder layer technique or conditioned medium enabled us to develop a fibroblast-free cultured middle ear epithelium. The availability of cultured middle ear epithelium provides a potential tool in future middle ear research.

Animals↗
PubMed1993

Cytological and histological changes in the middle ear after inoculation of influenza A virus.

Experimental otitis media induced in the chinchilla by inoculation of influenza A virus into the middle ear resulted in capillary engorgement, subepithelial hemorrhage, tissue edema and acute inflammatory cell infiltration. Quantitative morphometric measurements were made for 28 days. Ciliated cells appeared to be the primary target of this strain of influenza virus and demonstrated the greatest degree of damage. Three weeks were required to restore the ciliated epithelium in the tubotympanum to normal levels.

Animals↗
PubMed1992

A membrane-based force generation mechanism in auditory sensory cells.

Auditory outer hair cells can elongate and shorten at acoustic frequencies in response to changes of plasma membrane potential. We show that this fast bidirectional contractile activity consists of an electromechanical transduction process that occurs at the lateral plasma membrane and can be activated and analyzed independently in small membrane patches inside a patch electrode. Bidirectional forces are generated by increases and decreases in membrane area in response to hyperpolarization and depolarization, respectively. We suggest that the force generation mechanism is driven by voltage-dependent conformational changes within a dense array of large transmembrane proteins associated with the site of electromechanical transduction.

Animals↗
PubMed1992

Changes in the structure of the cell surface carbohydrates of the chinchilla tubotympanum following Streptococcus pneumoniae-induced otitis media.

Streptococcus pneumoniae (Spn) are among the most frequently isolated pathogens in acute otitis media (AOM) and in otitis media with effusion (OME). Recently, the specific receptor for Spn has been identified as the trisaccharide unit Gal beta 1-4 GlcNAc beta 1-3 Gal beta with GlcNAc beta 1-3 Gal beta as the principal binding site. During the colonization of mucosal surfaces, pneumococci produce a variety of enzymes. This study was conducted to identify any resulting changes in the cell surface carbohydrate structure due to the action of these enzymes during pneumococcal otitis media (OM) in chinchillas. Using a lectin histochemical method with seven different lectins (SNA, LFA, WGA, Succ WGA, BSL II, PNA, ECL), the labeling pattern revealed not only the removal of the terminal sialic acid, but also the exposure of N-acetyl-glucosamine. These results suggested that Spn-produced enzymes uncover part of their own receptor structure and thus may facilitate adherence and subsequent infection.

Acute Disease↗
PubMed1992

Effect of endotoxin on cultured chinchilla middle ear epithelium.

The effect of endotoxin on the growth and morphology of cultured chinchilla middle ear epithelium was examined. Within 24 hours of culture, cells maintained in medium containing endotoxin exhibited dose-dependent morphological changes. The highest concentration of endotoxin (100 mg) resulted in cell death. The growth curve of the cells in culture demonstrated a dose-dependent, significant increase in cell number when endotoxin was added to the medium.

Animals↗
PubMed1992

Expression of sialic acids in the developing murine tubotympanum.

Sialoglycoconjugates in the developing murine tubotympanum were characterized using lectin histochemistry with wheat germ agglutinin (WGA), Limax flavus agglutinin (LFA), Sambucus nigra agglutinin (SNA), Maackia amurensis agglutinin (MAA), peanut agglutinin (PNA), and neuraminidase treatment. WGA, LFA, MAA, and neuraminidase-PNA labeled epithelial goblet cells, glandular mucous cells, and cell surfaces of adult and newborn murine tubotympanum. SNA did not label any secretory components. PNA labeled secretory cells and cell surfaces of the fetal tubotympanum without neuraminidase treatment. After birth, these secretory cells and cell surfaces were labeled with PNA only after neuraminidase treatment. These results revealed that: Sialoglycoconjugates are produced from glandular mucous cells and epithelial goblet cells and are present on cell surfaces and within the mucous blanket; their terminal tri-saccharide linkage appears to be the sequence Neu5Ac(alpha 2-3)Gal(beta 1-3)GalNAc; sialic acids appear before birth and gradually increase; terminal galactose residues are masked by sialic acids after birth.

Aging↗
PubMed1992

Development of the mucociliary system in the eustachian tube and middle ear: murine model.

In order to describe the developmental anatomy of the murine eustachian tube and its related structures, seventy six mice of ages ranging from gestational day 11 to postnatal day 21 were investigated through the light and electron microscopic observations. Development of the ciliated cells was seen concurrently in both the eustachian tube and middle ear on the 16 th gestation day, one day earlier than the epithelial secretory cells appeared in both the eustachian tube and middle ear. The number of ciliated cells and secretory cells increased rapidly after birth. Tubal glands were well identified with evidence of secretory activity around the time of birth. Thus, the findings of this study indicate that the mucociliary defense system starts to develop during the fetal stage and is well established immediately after birth.

Animals↗