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Biomedical subjects

H B Kim

Publications and source records attributed to H B Kim.

At least 55 records · Page 3Linked to original sources
PubMed1998

Microchimerism and tolerance after in utero bone marrow transplantation in mice.

BACKGROUND: Donor-specific tolerance has been induced after both fetal and neonatal hematopoietic stem cell (HSC) transplantation in mice. However, the relationship between hematopoietic microchimerism and tolerance in these models has not been defined due to the insensitivity of donor cell detection methodology. To address this problem we developed a semiquantitative polymerase chain reaction (PCR)-based assay for detection of microchimerism after major histocompatibility (MHC) class I disparate HSC transplantation. This assay was used to examine the relationship between microchimerism and tolerance after fetal and neonatal transplantation of fully allogeneic bone marrow cells. MATERIALS AND METHODS: C57BL/6 mice (H2-Kb) were used as adult bone marrow donors and Balb/c mice (H2-Kd) were used as fetal or newborn recipients. A dose of 10(10) BM cells/kg was injected intraperitoneally into recipient animals. Peripheral blood of animals which survived beyond 3 weeks of age was analyzed by PCR for the presence of donor MHC class I DNA. Tolerance was tested by placement of donor-specific skin grafts after determination of chimerism status. RESULTS: Our assay was found to be specific for H2-Kb donor cells in an H2-Kd background with a sensitivity of <0.0001%. Of 49 animals injected in utero 19 (38%) had donor DNA present in peripheral blood at low levels (<0.1%) whereas only 1 of 18 neonatally injected animals had detectable donor cells (P < 0.01). Tolerance to donor-specific skin grafts was found in 6 of 9 animals which were chimeric after in utero HSC transplantation whereas none of the 18 neonatally injected animals including the chimeric animal were tolerant. CONCLUSIONS: Our results indicate the following. ( 1) Hematopoietic microchimerism can be detected by PCR in peripheral blood after in utero injection of fully allogeneic HSCs. ( 2) Fetal injections yield a higher incidence of microchimerism than newborn injections. ( 3) Tolerance can be induced across a fully allogeneic barrier by in utero HSC transplantation and this is associated with the presence of peripheral blood microchimerism.

Animals↗
PubMed1998

Analysis of zonular-free zone and lens size in relation to axial length of eye with age.

PURPOSE: To evaluate the anatomical relationships of the zonular-free zone (ZFZ) of the anterior capsule and crystalline lens diameter in relation to the axial length of the eye with age. SETTING: Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea, and Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHOD: Various ocular structures in 122 eyes obtained post-mortem were measured without prior preparation. The correlation between age, anterior-posterior (A-P) length and globe size, and diameters of the cornea, crystalline lens, and ZFZ were analyzed. RESULTS: The average A-P globe length, and corneal, lens, and ZFZ diameters were 24.48, 11.67, 9.65, and 6.93 mm, respectively. There was no significant relationship between A-P length and globe size and corneal diameter in different age groups. The ZFZ size varied negligibly among age groups. There was a statistically significant correlation between lens diameter and age (correlation coefficient = 0.2647; P < .01) and lens diameter and A-P globe length (correlation coefficient = 0.3183; P < .001). CONCLUSIONS: When choosing an intraocular lens, one should consider the patient's age and the A-P globe length. Six eyes (5%) showed unusual anterior insertion of zonular attachment, which reminds us to be prudent with a large paracentral capsulorhexis.

Adult↗
PubMed1998

Ideal size of an intraocular lens for capsular bag fixation.

PURPOSE: To determine the ideal size of an intraocular lens (IOL) for proper capsular bag fixation in different sizes of evacuated capsular bags. SETTING: Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea, and Storm Eye Institute Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Fifteen eyes obtained post-mortem were divided by crystalline lens size into three groups. Intraocular lenses of five different sizes were implanted in each capsular bag. The arc of contact between the haptics and capsular equator and the capsular bag distortion with each IOL were measured and compared using posterior-view analysis. RESULTS: The arc of contact was directly proportional to the IOL size and inversely related to the lens size. The smallest arc of contact was 2.0 mm with the smallest IOL implanted in the largest lens group. The maximum capsular bag distortion was 2.6 mm in the case of the largest IOL implantation in the smallest lens group. CONCLUSION: Implanting an IOL smaller than 12.5 mm in a large capsular bag can result in unstable fixation, while implanting an IOL larger than 12.5 mm in a small capsular bag can result in excessive stretching and distortion of the capsular bag and surrounding zonules.

Aged↗
PubMed1998

Comparison of corneal centering in photorefractive keratectomy.

The present study compares three centering methods for excimer laser photorefractive keratectomy (PRK. VISX 20/20) by analyzing the corneal topography. The subjects were grouped according to three different centering methods used in the procedure: an ablation using a light reflex from the patient's cornea pursued by both eyes of the surgeon (Group 1, n = 49); an ablation using a red light reflex from the patient's cornea pursued by the surgeon's left eye only while the right eye remained closed (Group 2, n = 27); an ablation using the patient's center of the pupil pursued by the surgeon's left eye only while the right eye remained closed (Group 3, n = 21). The mean distance from the center of ablation zone to the center of the pupil were; 0.69 +/- 0.45 mm for Group 1, 1.05 +/- 0.48 mm for Group 2 and 0.63 +/- 0.28 mm for Group 3. The degree of deviation in Group 2 was significantly greater than in Group 1 or Group 3. The deviation was greater in the right eyes than the left eyes in Group 2 only. The decentration of the right eye in Group 2 was due to angle Kappa with misalignment of the fixation light and viewing tube containing reticule.

Adult↗
PubMed1997

Orthodontic adhesives and bond strength testing.

A bracket bond failure is a frustrating occurrence in orthodontic practice. Because the location of the bond failure may indicate the probable cause, it is important to understand the significance of "bond strength" in a clinical application. Bonding in orthodontics can be studied using controlled clinical models or in vitro using simulated clinical models or more fundamental, isolated substrate models, in which bonding of an adhesive to tooth structure or a bracket is studied independently. With numerous adhesives and orthodontic band and bracket materials available as well as other orthodontic substrates besides enamel, such as esthetic ceramic restorations, in vitro models play an important role in characterizing the bonding potential of new systems. This article reviews bonding of orthodontic brackets and bands using various orthodontic adhesives to dental substrates from the perspective of bond strength and its measurement.

Acid Etching, Dental↗
PubMed1997

Ophthalmologic manifestation of Behçet's disease.

Loss of vision in Behçet's disease is one of the most common, as well as one of the most serious, of its varied manifestations. Total blindness may often be the eventual outcome. The underlying problem in the eye, as well as in other organ systems, is an occlusive vasculitis. Although the most common ocular symptom is that of iridocyclitis, the presence of retinovascular lesions, especially necrotizing retinitis, is well known but often obscured by the severity of the anterior reaction, which precludes a good view of the retina. While Behçet's disease is characterized by spontaneous remissions and relapses, no external factors have been found to explain the length of remissions. Blindness, which occurs in up to 25% of patients, is one of the major causes of permanent disability.

Behcet Syndrome↗
PubMed1996

Orthotopic liver transplantation for inflammatory myofibroblastic tumor of the liver hilum.

Inflammatory myofibroblastic tumor is a rare gastrointestinal neoplasm. The authors report the case of a 5-year-old girl who initially presented with gastric outlet obstruction secondary to an inflammatory myofibroblastic tumor along the lesser gastric curvature. A subtotal gastrectomy and wedge resection of a left hepatic lobe nodule were performed. Obstructive jaundice developed one month postoperatively. Computerized tomography, percutaneous transhepatic cholangiography, and selective celiac and mesenteric arteriography showed a mass that involved the left hepatic lobe, with concomitant high-grade biliary obstruction and portal venous encasement. Percutaneous biliary drainage was performed. During laparotomy, the tumor was found to be unresectable, and the patient was referred to the Liver Transplant Service at The Children's Hospital of Philadelphia. A total hepatectomy with temporary portocaval shunt was performed, leaving the inferior vena cava in situ. At the back table, an ex vivo left trisegmentectomy was performed, followed by reimplantation of the posterior segment of the right hepatic lobe. The reimplanted liver segment functioned poorly, and completion hepatectomy with portocaval shunt was performed 24 hours postoperatively, because of severe coagulopathy, intraabdominal bleeding, and hemodynamic instability. The patient's condition stabilized, and she was listed for urgent liver transplantation. The anhepatic state was managed with intermittent plasmapheresis. She had transplantation 72 hours later, and was discharged from the hospital 3 weeks postoperatively after an uneventful recovery. She remains disease-free and has normal liver function 8 months after transplantation.

Child, Preschool↗
PubMed1996

The effect of photorefractive keratectomy in Korea.

To assess the predictability and accuracy of photorefractive keratectomy (PRK) in myopia, we reviewed the charts of 182 patients who underwent PRK and were followed up for more than 12 months. The mean visual acuity was improved from 0.11 to 0.80 at 12 months postoperatively, and the mean refraction change shows from -7.94D to -0.89D. 47% of the treated eyes achieved final visual acuity of 1.0, and 97% achieved 0.5 or better. In the case of postoperative refraction, 96% of cases who were less than -6 D myopia achieved final refraction within +/- 1D, while 66% of cases who were more than -6 D myopia did. These results suggest that PRK is a safe and predictable procedure in treating mild to moderate myopia.

Adult↗
PubMed1995

Modification of the scleral openings to reduce tissue breakdown and exposure after hydroxyapatite implantations.

We compared the incidence of exposure of the hydroxyapatite implant after evisceration according to the position of scleral windows which allow rapid fibrovascularization into the implant. Three patients (10%) developed tissue breakdown and exposure of the hydroxyapatite, out of 30 patients who had external scleral windows located in a position just anterior to the insertion of each of the rectus muscles, whereas no patient developed exposure, out of 24 patients who had internal scleral windows located in a position just position just posterior to the insertion of each of the rectus muscles. Internal windows sealed with rectus muscles could prevent direct contact between implant and the overlying Tenon's capsule and conjunctiva. These findings seem to indicate that the rough spicular surface of the hydroxyapatite irritates and erodes the overlying Tenon's capsule and conjunctiva.

Biocompatible Materials↗
PubMed1995

Management of an abdominal cerebrospinal fluid pseudocyst using laparoscopic techniques.

Abdominal cerebrospinal fluid (CSF) pseudocysts are reported to occur in < 1% of ventriculoperitoneal shunts. Management options include various types of shunt revisions with or without aspiration or excision of the pseudocyst. We report a case in which laparoscopy was utilized in a 12-year-old boy to excise a portion of the pseudocyst, remove the shunt catheter tip from the residual pseudocyst, and reposition it in the peritoneal cavity. The patient experienced no complications from the procedure, and there has been no recurrence of the pseudocyst after 12 months of follow-up observation. This case report demonstrates a novel approach to the management of CSF pseudocysts that is minimally invasive, allows direct drainage of the pseudocyst, and permits manipulation and optimal repositioning of the shunt catheter.

Child↗
PubMed1994

Endothelial F-actin changes in the alkali burned rabbit cornea.

The healing mechanism of corneal endothelium after alkali burn was not completely understood. Rabbit cornea was burned with 1N sodium hydxoside for 1 minute. Endothelial F-actin was stained with NBD-phallacidin in regular sequence to find out the details of endothelial healing after alkali burn. F-actin was completely destroyed leaving a sharp margin against the unaffected area 1 hour after the burn. In the 3, 5 and 7 day specimens, highly active F-actin reactions were noted at the wound margin. New multiple F-actin layers, arising from the intact endothelium near the wound margin, were noted in the 9 day specimen. In the 8 1/2 month specimen, the endothelial defected area was covered by large primitive cells, each of which showed F-actin fiber bundles in the cytoplasm with a large nuclear shadow. Nearly all of the large primitive cells showed F-actin fibers arranged in shapes of cell junctions. Twelve months after the burn, endothelial defects were not found. Nearly all of the endothelial cells were normal in size and shape except for some mushroom-like projections toward the anterior chamber in some areas. Nineteen months after the burn, the endothelial cells were normal. Endothelial wound healing process can be continued even 1 year after the alkali burn in rabbit cornea.

Actins↗
PubMed1993

Digitally assisted laparoscopic drainage of multiple intraabdominal abscesses.

Laparoscopic drainage of multiple walled off intraabdominal abscesses may be difficult to perform safely due to a lack of tactile sensation. A single finger introduced through a small abdominal incision can be used to aid in the dissection and may obviate the need for open laparotomy in some cases. Digitally-assisted laparoscopic exploration and dissection utilizes the superior visualization of laparoscopy without completely sacrificing the benefits of tactile sensation. A case is reported in which this technique was successfully employed to drain multiple intraabdominal abscesses in a young boy.

Abdomen↗
PubMed1991

Cellular morphogenesis in the Saccharomyces cerevisiae cell cycle: localization of the CDC3 gene product and the timing of events at the budding site.

Budding cells of the yeast Saccharomyces cerevisiae possess a ring of 10-nm-diameter filaments, of unknown biochemical nature, that lies just inside the plasma membrane in the neck connecting the mother cell to its bud. Electron microscopic observations suggest that these filaments assemble at the budding site coincident with bud emergence and disassemble shortly before cytokinesis (Byers, B. and L. Goetsch. 1976. J. Cell Biol. 69:717-721). Mutants defective in any of four genes (CDC3, CDC10, CDC11, or CDC12) lack these filaments and display a pleiotropic phenotype that involves abnormal bud growth and an inability to complete cytokinesis. We showed previously by immunofluorescence that the CDC12 gene product is probably a constituent of the ring of 10-nm filaments (Haarer, B. and J. Pringle. 1987. Mol. Cell. Biol. 7:3678-3687). We now report the use of fusion proteins to generate polyclonal antibodies specific for the CDC3 gene product. In immunofluorescence experiments, these antibodies decorated the neck regions of wild-type and mutant cells in patterns suggesting that the CDC3 gene product is also a constituent of the ring of 10-nm filaments. We also used the CDC3-specific and CDC12-specific antibodies to investigate the timing of localization of these proteins to the budding site. The results suggest that the CDC3 protein is organized into a ring at the budding site well before bud emergence and remains so organized for some time after cytokinesis. The CDC12 product appears to behave similarly, but may arrive at the budding site closer to the time of bud emergence, and disappear from that site more quickly after cytokinesis, than does the CDC3 product. Examination of mating cells and cells responding to purified mating pheromone revealed novel arrangements of the CDC3 and CDC12 products in the regions of cell wall reorganization. Both proteins were present in normal-looking ring structures at the bases of the first zygotic buds.

Antibodies, Fungal↗
PubMed1991

Activity of chloramphenicol acetyltransferase overproduced in E. coli with wild-type and mutant GroEL.

The homo-oligomeric protein chloramphenicol acetyltransferase (CAT) has previously been shown to interact with a chaperone GroEL in vitro, suggesting a possible involvement of GroEL in CAT assembly. CAT was overproduced to various levels in the presence and absence of GroEL overproduction, and in groEL mutants. CAT was accumulated to 9-45% of total cellular protein in a fully soluble form, without formation of inclusion bodies. In all cases, even with groEL mutants, CAT specific activity was shown proportional to the amount of protein produced, indicating the formation of active trimer CAT structure does not need GroEL in Escherichia coli.

Bacterial Proteins↗
PubMed1990

Pharmacokinetics of intravitreally injected liposome-encapsulated tobramycin in normal rabbits.

Bacterial endophthalmitis, which is a devastating complication of intraocular surgery or eye trauma, has a poor prognosis. Intravitreal injection of antimicrobial agents has become a part of the standard treatment of endophthalmitis. The authors investigate the pharmacokinetics of intravitreal liposome-encapsulated tobramycin as a possible method of prolonging the duration of therapeutic concentrations. Tobramycin was encapsulated into liposomes of phosphatidylcholine, phosphatidic acid, and alpha-tocopherol by the reverse phase evaporation method. The final liposomal suspension contained tobramycin, 7.0 mg/ml, 60.5% encapsulated. One eye received an intravitreal injection of either liposome-encapsulated tobramycin (LET), tobramycin phosphated-buffered saline (TS) or a mixture of tobramycin and liposome-encapsulated saline (TEL), and the results were as follows: 1. Concentrations of free tobramycin were significantly lower with LET than with TS or TEL at 1 hour after intravitreal injection. 2. Concentrations of free and total tobramycin were significantly higher with LET than with TS or TEL at 5 and 8 days after intravitreal injection. Concentrations of free tobramycin with TS were lower than the minimal inhibitory concentration(MIC) of tobramycin for Pseudomonas aeruginosa at 8 days after intravitreal injection, while those with LET were higher than the MIC of tobramycin for Pseudomonas aeruginosa 18 days after injection.

Animals↗
PubMed1989

The incidence of congenital color deficiency among Koreans.

It is important to investigate the incidence of congenital color deficiency and to determine the type and degree because the color deficiency can effect as a handicap to certain occupations. The incidence of congenital color deficiency is remarkably constant among Caucasians but other races show considerable variations. We investigated the incidence of congenital color deficiency among Koreans by the use of H-R-R pseudoisochromatic plates. The present study revealed that the incidence of congenital color deficiency among Koreans was 31.5% (5.90% in men, 0.44% in women).

Color Vision Defects↗
PubMed1977

Marginal corneal ulcer due to beta-streptococcus.

A 72-year-old woman with a low-grade nasolacrimal duct obstruction developed a hyperacute conjunctivitis caused by beta-hemolytic streptococci. This condition has been termed "conjunctivitis of Morax". An unusual feature consisting of a large, marginal furrow-like corneal ulcer was noted associated with a plastic iritis. The condition improved with the use of topical erythromycin, irrigation of the lacrimal sac with aqueous penicillin and oral penicillin. We believe that the marginal corneal ulcer was an actual infection of the corneal stroma resulting from the intense conjunctival chemosis trapping the exudate between the conjunctiva and the corneal epithelium, thus causing a breakdown of the corneal epithelium and allowing the organism to gain access to the stroma. Conjunctivitis of Morax can be clinically differentiated from a conjunctivitis associated with pneumococcal dacryocystitis and from the acute and hyperacute purulent conjunctivis due to infection with Neisseria.

Aged↗