Keratocyte apoptosis: implications on corneal wound healing, tissue organization, and disease.
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Animals↗
Biomedical subjects
W J Kim
Publications and source records attributed to W J Kim.
Keratocyte apoptosis after corneal surgery.
PURPOSE: Programmed cell death (apoptosis) is the controlled death of cells that occurs with minimal collateral damage to surrounding cells or tissue during development, homeostasis, and wound healing. The authors hypothesize the keratocyte apoptosis is an initiating factor in the wound-healing response after refractive surgical procedures. To evaluate the effects of different corneal manipulations, keratocyte apoptosis was examined qualitatively and quantitatively after traditional epithelial scrape-photorefractive keratectomy (PRK), transepithelial PRK, removal of a cap of superficial cornea using a microkeratome, production of a flap of superficial cornea with a microkeratome, and laser-assisted in situ keratomileusis (LASIK) compared with unwounded controls in rabbit corneas. METHODS: Refractive surgical procedures or their components were performed in rabbit eyes. Keratocyte apoptosis was monitored using the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labeling assay to detect DNA fragmentation. Cellular morphologic changes were evaluated by electron microscope examination. RESULTS: Keratocyte apoptosis was noted with each refractive procedure or corneal manipulation and was variable from eye to eye with each procedure. Transepithelial PRK was associated with the lowest levels of central corneal apoptosis, even if the stromal surface was scraped after the procedure. Keratocyte apoptosis is confined to the superficial stroma extending to a depth of approximately 50 microns to 75 microns after epithelial scrape-PRK and transepithelial PRK. Apoptosis was noted in the deeper central corneal keratocytes located anteriorly and posteriorly to the lamellar cut in LASIK. CONCLUSIONS: There are qualitative and quantitative differences in keratocyte apoptosis between LASIK, epithelial scrape-PRK, and transepithelial PRK. Epithelial injury is an important factor modulating keratocyte apoptosis. The level and distribution of keratocyte apoptosis, along with subsequent repopulation by activated stromal keratocytes, are likely to be important determinants of corneal wound healing associated with variability and regression after PRK and LASIK. Transepithelial PRK induces low levels of keratocyte apoptosis, and, therefore, this approach may be useful for treating higher levels of myopia and for retreatment after regression.
Animals↗
Bone morphogenic proteins 2 and 4 and their receptors in the adult human cornea.
PURPOSE: To examine the expression of transforming growth factor family members bone morphogenic proteins 2 and 4 (BMP2, BMP4), their receptor mRNAs, and BMP2 and BMP4 proteins in the cells of the human cornea. The effects of BMP2 and BMP4 on corneal fibroblast proliferation and apoptosis were also examined. METHODS: Reverse transcription-polymerase chain reaction, immunoprecipitation, and western blot analysis were used to examine mRNA and protein expression in cultured human corneal cells. Immunocytochemistry was applied to examine protein localization in fresh frozen human cornea cells. Stimulation and inhibition of nuclear factor-kappaB (NF-kappaB) activation was evaluated by gel shift assay. Apoptosis was examined using trypan blue exclusion, laddering of DNA, CPP32 assay, and transmission electron microscopy. Proliferation was monitored by counting cells. RESULTS: BMP2 and BMP4 mRNAs and proteins were expressed in cultured human corneal epithelial cells, keratocytes, and corneal endothelial cells. BMP2 and BMP4 were detected in each major corneal cell type in fresh frozen human cornea. BMP receptor IA, IB, and II mRNAs were also detected in cultured human corneal epithelial cells, keratocytes, and endothelial cells. BMP2 and BMP4 stimulated activation of NF-kappaB. Actinomycin D and SN50 peptide, but not SN50M control peptide, inhibited NF-kappaB activation in response to BMP2 or BMP4. BMP2 and BMP4 stimulated apoptosis of corneal fibroblast cells when NF-kappaB activation was inhibited with the nonselective inhibitor actinomycin D or selective inhibitor SN50. The nonsteroidal anti-inflammatory agents ketorolac tromethamine and diclofenac sodium augmented the effect of BMP2 on corneal fibroblast apoptosis. BMP2 and BMP4 both stimulated proliferation of corneal fibroblast cells in the absence of inhibitors of NF-kappaB activation. CONCLUSIONS: BMP2, BMP4, and their receptors are expressed in the cells of the adult human cornea. The functions regulated by these cytokines may include keratocyte proliferation and apoptosis.
Adult↗
Effect of silkworm hemolymph on the expression of E. coli beta-galactosidase in insect cell lines infected with recombinant baculoviruses.
The effects of silkworm hemolymph on the expression of foreign genes by recombinant baculoviruses in cell lines were studied. The expression efficiency of beta-galactosidase by recombinant virus containing the E. coli lacZ gene at various concentrations of hemolymph and FBS was determined in BmN and Sf cell lines. The addition of hemolymph to the medium containing FBS accelerated the expression of beta-galactosidase by recombinant viruses in both cells. It was more effective in BmN cells than in Sf cells. Hemolymph was most effective in enhancing virus multiplicity under conditions of 5% FBS.
Animals↗
Rapid purification, partial characterization, and antimicrobial spectrum of the bacteriocin, Pediocin AcM, from Pediococcus acidilactici M.
The bacteriocin from Pediococcus acidilactici M, designated as Pediocin AcM, was rapidly purified to homogeneity by the pH mediated cell adsorption-desorption method and semi-preparative reversed-phase HPLC. The purification yield was 40.4% and the specific activity was increased by 2450-fold. It gave a single band and a single peak on SDS-PAGE and HPLC analysis, respectively. When subjected to electrospray LC-MS analysis, the protein was found to be highly pure and the molecular weight was determined as 4,618 Da. High concentration of the bacteriocin (> 50 micrograms/ml) showed good resistance to extremes of pH (1-12) and temperature (121 degrees C). Pediocin AcM was deduced to be a monomer with an intra-peptide disulfide bond from the results of reversed-phase analytical HPLC analyses after reduction, oxidation and trypsin digestion. P. acidilactici M inhibited a large number of bacteria, including Staphylococcus aureus, Listeria monocytogenes, Clostridium perfringens, Bacillus coagulans, B. cereus, and Aeromonas hydrophila.
Bacteriocins↗
Adding posterior lumbar interbody fusion to pedicle screw fixation and posterolateral fusion after decompression in spondylolytic spondylolisthesis.
STUDY DESIGN: This is a retrospective study analyzing 76 patients treated by decompression, pedicle screw instrumentation, and fusion for spondylolytic spondyiolisthesis with symptomatic spinal stenosis. OBJECTIVES: To verify the advantages of adding posterior lumbar interbody fusion to the usual posterolateral fusion with pedicle screw instrumentation. SUMMARY OF BACKGROUND DATA: Stabilization after decompression of spondylolytic spondylolisthesis is difficult because of a lack of fusional bone bases, gap between the transverse process bases, and incompetent anterior disc support. Posterior lumbar interbody fusion offers anterior support, reduction, and a broad fusion base. METHODS: Forty patients were treated with posterolateral fusion, and 36 were treated with additional posterior lumbar interbody fusion. They were compared for union, reduction of the deformity, and clinical results. RESULTS: The patients were followed up for more than 2 years. Nonunion was observed in three patients who underwent posterolateral fusion (7.5%), and no cases of nonunion was found in patients who underwent posterior lumbar interbody fusion. Reduction of slippage was 28.3% in those who underwent posterolateral fusion and 41.6% in those who had posterior lumbar interbody fusion (P = 0.05). In the posterolateral fusion group, eight patients (20%) had recurrence of deformity, with loss of reduction more than 50%. Hardware failures occurred in two patients who had posterolateral fusion. There was no major neurologic complications in both groups. Both groups had satisfactory results in more than 90% of patients, with marked improvement of claudication. However, subjective improvement of back pain by Kirkaldy-Willis criteria revealed differences in the excellent results. An excellent result was reported by 45% in the posterolateral fusion group and by 75% in posterior lumbar interbody fusion group. CONCLUSIONS: The addition of posterior lumbar interbody fusion to posterolateral fusion after a complete decompression and pedicle screw fixation is a recommended procedure for the treatment of spondylolytic spondylolishesis with spinal stenosis.
Adult↗
Apoptosis in the cornea: further characterization of Fas/Fas ligand system.
This study was performed to further characterize expression and function of the Fas/Fas ligand system in the cornea. Specifically, these experiments examined (1) the effect of genetic inactivation of Fas or Fas ligand genes on keratocyte apoptosis in response to corneal epithelial wounding, (2) whether cultured human corneal epithelial and endothelial cells are competent to undergo apoptosis in response to Fas activation, (3) expression of membrane bound and soluble Fas and Fas ligand in corneal cells, and (4) the effect of IL-1 on expression of Fas and Fas ligand in corneal fibroblasts. Keratocyte apoptosis in response to corneal epithelial scrape detected by TUNEL assay and transmission electron microscopy was significantly decreased, but not eliminated, in Fas ligand -/- mice compared with control +/+ mice. There was also a decrease in Fas -/- mice that did not reach statistical significance. Thus, while the Fas/Fas ligand system is likely involved in regulating keratocyte apoptosis in response to epithelial wounding, systems with redundant function probably also modulate this response. Activation of the Fas receptor triggered death with ultrastructural changes characteristic of apoptosis in corneal epithelial and endothelial cells in culture. Since these cell types express both Fas and Fas ligand in vivo, systems must be in place to prevent uncontrolled activation via autocrine ligand-receptor interaction. Messenger RNAs coding for both membrane bound and soluble splicing variants of Fas were expressed in each corneal cell type, suggesting that soluble Fas production could be one mechanism to antagonize membrane bound Fas activation. Soluble Fas ligand protein was expressed in wounded ex vivo corneal epithelium, providing a mechanism for Fas ligand from epithelium to mediate keratocyte apoptosis. IL-1, however, also stimulated corneal fibroblasts to express Fas ligand mRNA and protein. Therefore, an alternative mode for epithelial injury to trigger keratocyte apoptosis may be by release of IL-1, subsequent induction of Fas ligand in keratocytes, and apoptosis mediated by autocrine mechanisms.
Animals↗
Multifactorial involvement of multidrug resistance-associated [correction of resistance] protein, DNA topoisomerase II and glutathione/glutathione-S-transferase in nonP-glycoprotein-mediated multidrug resistance in human bladder cancer cells.
BACKGROUND: Multiple mechanisms are important in multidrug resistance in urothelial cancers. We investigated the acquisition of a multidrug resistance phenotype in human bladder cancer cells exposed to doxorubicin. METHODS: Human bladder cancer cell line 5637 and 2 doxorubicin drug-resistant sublines (5637/DR5.5 and 5637/DR50) were used. Measurements were made of the steady state mRNA levels of the multidrug resistance gene (mdr1), multidrug resistance-associated protein (MRP), glutathione-S-transferase-pi and DNA topoisomerase II (topo II) genes, P-glycoprotein (PgP) and MRP expression, glutathione (GSH) and GSH enzyme activity, and topo II catalytic activity. The pharmacokinetics were compared between the parent and the drug-resistant sublines. RESULTS: 5637/DR5.5 and 5637/DR50 cells were 7.6- and 16.2-fold more resistant to doxorubicin and 16.7- and 48.3-fold more resistant to etoposide, respectively, compared with 5637 cells. A dose escalation of doxorubicin increased the MRP expression, GSH levels and glutathione-S-transferase (GST) activity, although no PgP expression was observed in any cell line. Resistance was brought about by decreased drug accumulation through drug efflux, although intracellular daunorubicin concentrations were similar between DR5.5 and DR50 cells. Topo II catalytic activity was undetectable in DR50 cells, but maintained in both the parent and DR5.5 cells. CONCLUSION: Reduced drug accumulation in doxorubicin-resistant cells was mediated by MRP instead of PgP indicating that MRP-mediated drug efflux functions in a limited manner for drug resistance. An increase in drug efflux via MRP, reduced topo II activity, and increased GSH levels/GSH-related enzyme activities may play major roles in nonPgP-mediated multidrug resistance in urothelial cancers treated with anthracyclines.
ATP Binding Cassette Transporter, Subfamily B, Mem↗
Single photon emission computed tomography-EEG relations in temporal lobe epilepsy.
The role of single photon emission computed tomography (SPECT) as an independent confirmation test in presurgical evaluation of medically intractable temporal lobe epilepsy has not been critically investigated. Because spreading ictal discharges may cause a concomitant increase of cerebral blood flow in remote cerebral regions, a careful analysis of peri-injection EEG patterns and their relation to ictal SPECT may be important in evaluating the reliability of ictal SPECT. Both interictal and ictal EEG and SPECT were reviewed in 19 patients with temporal lobe epilepsy who achieved a successful seizure outcome after surgery. Patients were divided into unitemporal and bitemporal groups according to the lateralization of interictal epileptiform discharges (IED). Ictal EEG features were classified into lateralized and nonlateralized groups. The concordance between SPECT and EEG lateralizations was examined in each patient and correlated to the documented epileptogenic temporal lobe. Interictal SPECT correctly lateralized in eight of nine patients with unitemporal IED and in five of 10 patients with bitemporal IED. Ictal SPECT was highly concordant with the peri-injection ictal EEG but correctly lateralized the epileptogenic region in only 11 of 19 patients. When both pre- and postinjection EEG epochs lateralized ipsilaterally, all ictal SPECT images showed concordant lateralization. If pre- and postinjection EEG epochs were either different in lateralization or nonlateralization, ictal SPECT images often showed complex patterns of cerebral perfusion with a high incidence of false lateralization. Interictal SPECT was more sensitive and reliable in patients with unitemporal IED than in patients with bitemporal IEDs. Ictal SPECT was closely related with peri-injection EEG epochs but with frequent false lateralization. The role of ictal SPECT as an independent confirmation test in presurgical evaluation should be reappraised.
Adolescent↗
Experiences of epilepsy surgery in intractable seizures with past history of CNS infection.
We studied the clinical characteristics, location of epileptogenic regions, and the surgical outcomes in 18 patients with intractable epilepsy associated with previous CNS infections. All patients underwent an extensive presurgical evaluation and 11 patients had intracranial EEG monitoring. On the basis of presurgical evaluation, epileptic regions were localized to the mesial temporal (n = 12) and the neocortical (n = 6) regions. The age of the time of CNS infection was significantly younger and the latent period of non-febrile seizures after CNS infection was longer in patients with mesial temporal lobe epilepsy (MTLE). MRI showed hippocampal atrophy and hippocampal signal changes in 11 of 12 patients with MTLE. Among 6 patients with neocortical epilepsy (NE) 5 patients had normal MRI and one showed cerebral hemi-atrophy. Surgery was successful (class I & II) in all patients with MTLE, however, in the patients with neocortical epilepsy, seizure-free results were not achieved in any patients after resective surgery (6 patients) and only 2 patients achieved Class II outcomes after a second epilepsy surgery consisting of neocortical resection. Patients with MTLE after CNS infection were differentiated from the group of neocortical epilepsy by an earlier onset of CNS infection, a prolonged latent period and a higher frequency of meningitis. The characteristic pathology in this group was hippocampal sclerosis and the surgical result was excellent. Neocortical epilepsy following CNS infection usually had no focal lesion on MRI and was associated with a relatively poor surgical result. This study suggested that the surgical outcome was influenced by the type of epileptic syndromes rather than the etiology of seizures. The association of MTLE with the younger age of CNS infections and with meningitis more frequently suggested that the neocortical neurons during infancy or early childhood may be more resistant to the epileptogenesis, or that the CNS infections in patients with MTLE might be milder in severity to cause selective injuries to the hippocampal neurons during their vulnerable stage.
Adolescent↗
Overexpression of human mutT homologue gene messenger RNA in renal-cell carcinoma: evidence of persistent oxidative stress in cancer.
Data regarding oxidatively modified DNA bases suggest that cancer cells are more exposed to oxidative stress than adjacent non-tumorous tissue. This novel concept may contribute to the understanding of certain aspects of tumor biology such as activated transcription factors, genetic instability, chemotherapy-resistance and metastasis. We therefore tested this concept in human renal-cell carcinomas (RCCs) by evaluating the expression of hMTH1, an enzyme preventing the misincorporation into DNA of 8-oxo-dGTP (8-oxo-7,8-dihydrodeoxyguanosine triphosphate), an oxidized form of dGTP in the nucleotide pool. The expression of hMTH1 messenger RNA (mRNA) in RCC was significantly higher than that in adjacent non-tumorous kidney. Moreover, advanced-stage tumors showed significantly higher hMTH1 mRNA expression than early-stage tumors, and there was a modest linear correlation between hMTH1 expression and c-myc expression. The results provide logical support for the concept of "persistent oxidative stress in cancer" and suggest a role of hMTH1 mRNA level as a prognostic marker.
Bacterial Proteins↗
Effect of optic zone size on the outcome of photorefractive keratectomy for myopia.
PURPOSE: To determine the effect of optic zone size on the outcome of photorefractive keratectomy (PRK) for myopia. SETTING: Department of Ophthalmology, Samsung Medical Center, Seoul, Korea. METHODS: Twenty patients, 10 with myopia under 6.00 diopters (D) and 10 with myopia over 6.00 D, had bilateral PRK with identical dioptric corrections in both eyes. One eye was treated with a 5.0 mm diameter optic zone and the other with a 6.0 mm diameter optic zone. An identical postoperative eyedrop regimen was used. During the 6 month follow-up, changes in refraction, uncorrected visual acuity, and corneal anterior stromal haze were evaluated. At the end of the follow-up, patients completed a questionnaire on night-vision disturbance, foreign-body sensation, tenderness, and preference. RESULTS: Two weeks postoperatively, eyes with a 5.0 mm optic zone had a significantly greater hyperopic shift than those with a 6.0 mm optic zone. Eyes with myopia over 6.00 D and a 6.0 mm optic zone had significantly faster recovery of uncorrected visual acuity at 2 and 12 weeks. There was no increased anterior stromal haze in the 6.0 mm optic zone eyes, despite the deeper stromal ablation. Night-vision problems were more prevalent in the 5.0 mm optic zone group, which also had a greater incidence of ablation decentration. CONCLUSION: A 6.0 mm optic zone for myopic PRK seems to produce better outcomes. Further evaluation of long-term results is needed.
Adult↗
Expression of multidrug resistance-related genes (mdrl, MRP, GST-pi and DNA topoisomerase II) in urothelial cancers.
OBJECTIVE: To characterize the multidrug resistance (MDR) phenotype in human urothelial cancers, the expression levels of four MDR-related genes (multidrug resistance, mdrl; multidrug resistance-associated protein, MRP; glutathione S-transferase-pi, GST-pi; and DNA topoisomerase II, topo II) were analysed in urothelial cancers. MATERIALS AND METHODS: Fifty-two tumour tissue and three normal urothelial mucosa samples were obtained from 44 patients with urothelial cancers. The expression of each gene was analysed with a reverse-transcription polymerase chain reaction (RT-PCR) method using beta 2-microglobulin (b2m) mRNA as an endogenous control. Levels of expression were expressed as the ratio of the specific products of the target gene to those specific to b2m. RESULTS: In primary urothelial cancer tissues, the mean (SD) expression of mdrl, MRP, GST-pi and topo II relative to b2m expression were 0.067 (0.061), 0.27 (0.23), 0.35 (0.31) and 0.12 (0.05), respectively. The mean expressions of MRP and GST-pi were higher than those of mdrl and topo II. The mean ratios of mdrl/b2m, MRP/b2m, GST-pi/b2m and topo II/b2m in normal urothelial mucosa were 0.06 (0.03), 0.12 (0.09), 0.30 (0.32) and 0.14 (0.01), respectively. There was no significant association of the expression of each gene with either the grade or extent of the primary tumour. The level of MRP expression in each sample was correlated significantly with the expression of mdrl and GST-pi in the urothelial cancers (r = 0.637 and 0.537, respectively). Chemotherapy did not markedly influence the induction of expression of the MDR-related genes, except for one case in which mdrl expression was 15 times greater than before chemotherapy. The expression of GST-pi in the patients not receiving chemotherapy was significantly higher than in those that did. CONCLUSIONS: These results suggest that the activation of MRP and GST-pi expression occurs during the tumorigenesis of urothelial cancers and that it may confer de novo and acquired drug resistance on urothelial cancers. These results should provide further insight into the complex role postulated for MDR-related genes in chemotherapy, carcinogenesis and tumour progression.
DNA Topoisomerases, Type II↗
Behavioral manifestations of genetic disorder.
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Adolescent↗
Expression patterns of multidrug-resistance (MDR1), multidrug resistance-associated protein (MRP),glutathione-S-transferase-pi (GST-pi) and DNA topoisomerase II (Topo II) genes in renal cell carcinomas and normal kidney.
PURPOSE: Expression levels of the multidrug-resistance (mdr1), multidrug resistance-associated protein (MRP), glutathione-S-transferase-pi (GST-pi) and DNA topoisomerase II (Topo II) genes in normal kidney and renal cell carcinomas were analyzed to study the complexity of the roles of these genes. MATERIALS AND METHODS: The reverse transcription-polymerase chain reaction (RT-PCR) assay was used with beta 2 microglobulin (beta 2 m) as the internal control. RESULTS: In normal kidneys, the expression levels of the 4 genes in individual normal kidney samples correlated significantly with one another. Comparisons of the expression levels between normal kidneys and renal cell carcinomas showed that only the mean MRP gene expression level was higher in renal cell carcinomas than in normal kidneys (p = 0.018). The expression patterns of the 4 genes in renal cell carcinomas differed markedly for nonpapillary and papillary tumors. The mean MRP/beta 2 m ratio for the papillary type was significantly lower than that for the nonpapillary alveolar type carcinoma (p = 0.004). The 4 genes showed moderate positive correlations with one another in alveolar type renal carcinoma similar to the correlations observed in normal kidneys. In contrast, in papillary type, MRP expression was inversely correlated with mdr1 and Topo II expression. CONCLUSION: Differences in cytogenetic changes, origins and natural histories between papillary and nonpapillary carcinoma may be associated with these distinct expression patterns of the resistance-related genes. Further study is required to clarify whether the differences in the expression patterns between these 2 structural types of carcinoma affect their chemosensitivities and clinical outcomes.
ATP-Binding Cassette Transporters↗
Segmental pedicle screw fixation in the treatment of thoracic idiopathic scoliosis.
STUDY DESIGN: This retrospective clinical study compared the results of correction of idiopathic thoracic scoliosis using Cotrel-Dubousset segmental pedicle screw fixation with those of hooks and screws inserted in a hook pattern. OBJECTIVES: The study's objective was to evaluate the efficacy and safety of segmental pedicle screw fixation in the management of idiopathic thoracic scoliosis. SUMMARY OF BACKGROUND DATA: Seventy-eight idiopathic thoracic scoliosis patients were treated with Cotrel-Dubousset instrumentation from 1987 to 1991. Thirty-one were treated with hooks; 23 were treated with pedicle screws inserted in a hook pattern; and 24 were treated with segmental pedicle screws. METHODS: After a minimum follow-up of 2 years (range, 25-52 months), the results of frontal, sagittal, and rotational correction of each group were compared and statistically analyzed using analysis of variance. RESULTS: Major curve correction was 55% with hooks, 66% with hook pattern screws, and 72% with segmental screws, with loss of correction of 6%, 2%, and 1%, respectively. Compensatory curve correction was 57% with hooks, 67% with hook pattern screws, and 70% with segmental pedicle screws. In patients with hypokyphosis, all showed significant improvement with best restoration in segmental screws. Rotational correction of the apical vertebra measured by the Perdriolle method was 19% with hooks, 26% with hook pattern screws, and 59% with segmental screws. Thirteen screws (3%) were malpositioned, but they did not cause neurologic impairment or adversely affect the results of treatment. CONCLUSIONS: Segmental pedicle screw fixation is a safe and effective method for correcting the triplanar deformity of the idiopathic thoracic scoliosis.
Adult↗
International adoption: a case review of Korean children.
In contrast to the controversial transracial adoption of African American children by Caucasian families in the U.S., international, transracial adoption of Asian children has not received much scientific or societal attention. There has been a steady increase in this unnoticed minority group, made up largely of Korean children. This paper reviews the developmental characteristics of post-adoption adjustments among Korean adoptees and discusses the dynamics of their positive adjustments. Sociopolitical issues of international adoptions are also addressed.
Acculturation↗
A training guideline of cultural competence for child and adolescent psychiatric residencies.
The author proposes a curriculum guideline of cultural competence for child and adolescent psychiatric residencies, including specific educational objectives, didactic topics and suggested references. These guidelines can be easily incorporated into the existing training curriculum and stress ethnogeneric and developmental perspectives, which can be expanded further to include ethnospecific issues depending on the needs of each training program and trainee.
Adolescent↗