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Biomedical subjects

C K Joo

Publications and source records attributed to C K Joo.

46 records · Page 3Linked to original sources
PubMed1995

T-cell mediated responses in a murine model of orthotopic corneal transplantation.

PURPOSE: To evaluate the role that delayed-type hypersensitivity (DTH) and cytotoxic T lymphocyte responses play in a murine model of orthotopic corneal allograft transplantation. METHODS: Corneal transplantation was performed by grafting C57BL/6 donor corneas into BALB/c corneal beds. After transplantation, the mice were observed by slit lamp biomicroscopy on a weekly basis and graded for signs of graft rejection and delayed-type hypersensitivity (DTH) and cytotoxic T lymphocyte (CTL) responses to donor alloantigens assessed at selected times after grafting. RESULTS: It was determined that between 40% and 65% of BALB/c mice rejected C57BL/6 corneas by 8 weeks after engraftment. Mice with opacity scores > 2 demonstrated significantly greater DTH responses than did mice with opacity scores < 2 at 2, 3, and 4 weeks after engraftment. After 4 weeks, the DTH responses for all groups were essentially the same as for naive BALB/c mice. The DTH responses were specific for C57BL/6 alloantigens and are primarily directed against non-major histocompatibility complex (MHC) C57BL/6 alloantigens and are primarily directed against non-major histocompatibility complex C57BL/6 alloantigens, as evidenced by the ability of B10.D2 cells to elicit DTH responses whereas C.B10-H-2b cells did not. However, although BALB/c mice engrafted with C57BL/6 tail skin demonstrated significantly greater CTL activity than naive BALB/c mice, there was no significant difference in CTL activity between BALB/c mice whose C57BL/6 corneal allografts displayed opacity scores greater than (rejected) or less than (accepted) 2. CONCLUSIONS: The mechanism whereby corneal allografts in this strain combination are rejected is best associated with the ability to generate strong DTH responses and not CTL activity. This DTH response also demonstrates alloantigen specificity and appears to be primarily directed against the non-MHC component of the corneal transplant.

Animals↗
PubMed1994

In vitro propagation of primary and extended life span murine corneal endothelial cells.

PURPOSE: To establish primary and extended life span cell cultures of murine corneal endothelial cells for a model system investigating corneal endothelial cell replacement and the immunologic features of corneal graft rejection. METHODS: The authors have been able to grow corneal endothelium in culture by isolating adult murine Descemet's membrane and allowing the endothelial cells to proliferate from the explants. To isolate extended life span murine corneal endothelial cells, cells were infected with an adenovirus-SV40 hybrid virus (Ad12-SV40). RESULTS: The primary cells from adult corneas proliferated to passage 3 before growth arrest-senescence was observed. However, the extended life span cells remained proliferative through passage 36 and maintained a structure similar to the primary cells. Immunohistochemical analysis demonstrate that the extended life span cells are SV40 large T antigen positive, and both the primary and extended life span murine corneal endothelial cells exhibit the common expression of several growth factor receptors and TGF-beta. CONCLUSIONS: This is the first report of the isolation and culture of mouse corneal endothelial cells. Additionally, these cells have been infected with a virus carrying the SV40 large T antigen, which yields extended life span mouse corneal endothelial cells. These cells will be of interest in establishing a murine model for corneal cell transplantation, and the authors are currently establishing protocols for the specific introduction and manipulation of these cells in both in vitro and in vivo systems. These types of analyses may provide an important animal model specific to in vivo corneal endothelial cell replacement for the treatment of endothelial-related keratopathies and can be a useful model in delineating the immunologic parameters of corneal graft rejection.

Animals↗
PubMed1993

Malignant melanoma in ten-month-old patient diagnosed by magnetic resonance imaging.

Here we report a case of choroidal malignant melanoma in a 10-month-old child, who has café-au-lait spots on the abdomen. She had suffered from enlargement of the eyeball since 5 months old due to a tumor-like mass in the vitreous cavity. It was examined with slitlamp biomicroscopy, indirect ophthalmoscopy, orbit computerized tomography and magnetic resonance imaging (MRI). Retinoblastoma or neurofibroma was suspected from the clinical diagnosis, and from the tomographic point of view, it could be choroidal hemangioma, however, the MRI study, unexpectedly suggested the possibility of choroidal malignant melanoma, and it could be confirmed by the results of a histopathologic examination.

Choroid Neoplasms↗
PubMed1992

Effect of neodymium:YAG laser photodisruption on intraocular lenses in vitro.

Poly(methyl methacrylate) (PMMA) based intraocular lenses (IOLs) such as injection-molded PMMA and lathe-cut PMMA IOLs and soft IOLs such as silicone and poly(hydroxyethyl methacrylate)(polyHEMA) IOLs were tested for vulnerability to Nd:YAG laser photodisruption. The laser beam was focused on the posterior surface and inside of the IOLs in balanced salt solution. Cracks and central defects with radiating fractures were observed in PMMA IOLs; blistered lesions and localized pits were observed in silicone and polyHEMA IOLs, respectively. A molten edge surrounding the large hole, which was an indication of the thermal effect of the laser, was observed in the injection-molded PMMA while only a minute lesion was found in the polyHEMA IOL which contained 38% water. The size of the superficial damage of the IOL increased as the power of laser irradiation increased and PMMA IOLs showed greater damage than soft IOLs (P < .05).

Lasers↗
PubMed1992

Compatibility of intraocular lenses with blood and connective tissue cells measured by cellular deposition and inflammatory response in vitro.

Injection molded poly(methyl methacrylate) (IM-PMMA), lathe-cut PMMA (LC-PMMA), heparin surface modified PMMA (HSM-PMMA), silicone, and polyhydroxyethyl methacrylate (polyHEMA) intraocular lenses (IOLs) were incubated with platelets, granulocytes, mouse macrophage-like RAW 264.7 cells and mouse fibrosarcoma L929 cells to examine their compatibility. The number of cells attached to the IOL was counted after the central IOL area (0.04 mm2) was photographed with an inverted light microscope. Cell morphology was examined by scanning electron microscopy (SEM). More platelets and granulocytes were attached to the IM-PMMA and silicone IOLs than to the HSM-PMMA and polyHEMA IOLs (P less than .05). RAW 264.7 and L929 cells grew on PMMA-based and silicone IOLs, whereas HSM-PMMA and polyHEMA IOLs did not support an abundant growth of these cells. Granulocytes were incubated with the IOLs in the presence of Luminol and the generation of chemiluminescence was measured. Poly(methyl methacrylate)-based IOLs caused granulocytes to release significant amounts of oxygen radicals, while the polyHEMA IOL was almost inactive in stimulating granulocytes. Silicone and HSM-PMMA IOLs showed an intermediate level of stimulating activity. The light intensity reached a peak within 14 minutes with the IM-PMMA IOL, and in about 18 minutes with the other IOLs. Our results suggest that IOL hydrophilicity prevents attachment of cells and that a hydrophilic, soft surface can discourage granulocyte stimulation.

Animals↗
PubMed1992

Prostaglandin E in rabbit aqueous humor after Nd-YAG laser photodisruption of iris and the effect of topical indomethacin pretreatment.

Ocular changes (prostaglandin E, protein, pupil diameter, and intraocular pressure) induced by photodisruption of pigmented rabbit iris with neodymium-yttrium aluminum garnet (Nd-YAG) laser and the effect of topical indomethacin upon those changes were examined. Concentrations of prostaglandin E in laser-treated eyes (1,3,5,10, and 20 lesions) were substantially greater than those in normal eyes and were associated with an initial hypertensive response. This finding was particularly striking in the case of 20 lesions. In that case, concentrations of prostaglandin E increased 50-fold, from 99 pg/ml of control level to 5049 pg/ml 60 min after irradiation. Disruption of blood aqueous barrier measured by protein concentration, changes in intraocular pressure, and pupil diameter occurred at a similar dose range of laser application. Concentration of protein and changes in pupil diameter already were prominent at 15 min after laser treatment, and changes in intraocular pressure were prominent at 60 min. Indomethacin pretreatment abolished most of these responses, suggesting that acute reactions following photodisruption largely depended on prostaglandin synthesis in iris tissue.

Administration, Topical↗
PubMedDate not supplied

Inhibitory effect of 2'-O-benzoylcinnamaldehyde on vascular endothelial cell proliferation and migration.

PURPOSE: To evaluate the inhibitory effect of the farnesyl transferase inhibitor 2'-O-benzoylcinnamaldehyde (CB 2'-ph) on proliferation and migration of vascular endothelial cells. METHODS: Bovine lens epithelial cells, bovine corneal endothelial cells, bovine keratocytes, bovine aortic endothelial cells (BAECs) and human umbilical vein endothelial cells (HUVECs) were treated with CB 2'-ph to determine its cell type specificity and antiproliferative effect. For inhibition of vascular endothelial cell growth factor (VEGF)- or basic fibroblast growth factor (bFGF)-induced proliferation of HUVECs, these cells were treated with various concentrations of CB 2'-ph. To assess the proliferation, MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) assay was used. The migration assay was also performed to determine the effect of CB 2'-ph on HUVECs. The distance of HUVEC outgrowth was measured from the scraped edge of a monolayer after treatment with CB 2'-ph concentrations of 0, 1.5 and 2.5 microg/ml for 24, 48 and 72 h. RESULTS: The CB 2'-ph had an inhibitory effect on all tested types of cell proliferation but only HUVEC and BAEC proliferation was specifically inhibited in a dose-dependent manner. In addition, CB 2'-ph inhibited VEGF- or bFGF-induced proliferation and migration of HUVECs in a dose-dependent manner. CONCLUSIONS: These results indicate that CB 2'-ph, a farnesyl transferase inhibitor is thought to be an effective inhibitor of vascular endothelial cell proliferation and migration.

Acrolein↗
PubMedDate not supplied

The expression of multiple cytokines and inducible nitric oxide synthase in experimental melanin-protein-induced uveitis.

We investigated the kinetics of multiple cytokines and inducible nitric oxide synthase (iNOS) in experimental uveitis induced by bovine melanin protein (BMP) for the proper treatment of uveitis. Experimental uveitis was induced in male Lewis rats by injection of BMP. The levels of various inflammatory cytokines and iNOS mRNAs were semiquantified by the reverse-transcriptase reaction followed by PCR. The uveitis was started to develop at approximately day 14 and peaked around 21 days after immunization. The signs of uveitis disappeared by 4 weeks after immunization. When the inflammation was severest, TNF-alpha, IL-1alpha, IL-10, IFN-gamma and iNOS mRNA increased to their peak, which varied with the degree of induction and different time course. We concluded that both cytokines and iNOS might modulate the inflammation at different states of experimental melanin-protein-induced uveitis. Their combination will be necessary for an effective treatment of inflammation.

Animals↗
PubMedDate not supplied

Photorefractive keratectomy in 202 myopic eyes: one year results.

We performed one-step procedures of photorefractive keratectomy (PRK) with the use of the excimer laser (193 nm) on 1519 myopic eyes during 1 year. From this group, we prospectively evaluated visual and refractive results of 202 (13%) consecutive myopic eyes that were followed for more than 1 year. Myopic eyes were divided into two groups according to the amount of myopia: group I, 135 eyes, 87 patients, less than -7.00 D, and group II, 67 eyes, 48 patients (-7.25 D to -13.50 D). The excimer laser system used was the ExciMed 200UV (Summit Technology, Inc, Waltham, Mass), the one-step computer program was fixed at a maximum ablation up to -6.00 D correction. Uncorrected visual acuity of 20/25 or better was achieved in 89.6% of eyes in group I and 47.8% in group II at 1 year. Best spectacle corrected visual acuity was equal to, or better than, the preoperative level in 93.8% of eyes. The difference between attempted and achieved refractive correction was within +/- 1.00 D in 91.4% in group I, and 51.7% in group II. The mean reduction of manifest (spherical equivalent) refraction in group II was 6.84 D at 1 year. Keratometric readings and central corneal thickness showed gradual changes until 6 months after surgery. Corneal haze disappeared in most of eyes at 1 year. The most common subjective complaint was glare and/or decreased vision at night or under dim light.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗