Leiomyoma of the breast in a 50-year-old woman receiving tamoxifen.
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Antineoplastic Agents, Hormonal↗
Biomedical subjects
E K Kim
Publications and source records attributed to E K Kim.
A simple method for the removal of epithelium grown beneath the hinge after LASIK.
The purpose of this study is to demonstrate a method of how to remove epithelium grown beneath the hinge area after laser in situ keratomileusis (LASIK) without affecting the refractive part of the lenticule. In three cases, an incision was made at the base of the hinge by RK diamond knife to free the lenticule from the stroma. The lenticule was lifted from the nasal edge. The epithelium grown along the interface beneath the hinge area was removed with a Bard-Parker No. 15 knife. The lenticular flap was repositioned with interrupted sutures using 10-0 nylon. No further epithelial ingrowth was observed. The central cornea remained clear leaving a peripheral ring-shaped opacity without affecting the preoperative naked visual acuity. In conclusion, epithelial ingrowth along the interface after LASIK can be removed safely without affecting the refractive part by the incision of the hinge area with a RK diamond knife, removal of the epithelium, and suturing of the lenticule to the stromal bed.
Adult↗
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↗
Three-dimensional gray scale ultrasonographic imaging of the celiac axis: preliminary report.
The vessels of the celiac axis were evaluated in 16 healthy volunteers with three-dimensional gray scale ultrasonography. Sonographic volume data sets were obtained from both sagittal and transverse planes. The visualization of specific branches of the celiac artery (hepatic, splenic, left gastric, gastroduodenal, left hepatic, right hepatic, right gastric) was evaluated, and each vessel was placed in one of four categories on the basis of the appearance of the specific vessel and image clarity (not seen, poorly seen, adequately seen, well seen). Each vessel was evaluated on an initial two-dimensional scan and on a second scan using the entire volume to optimize and follow the designated vessel using rotating, referencing, and scrolling display capabilities. The ability to manipulate an entire volume improved visualization of the selected vessels as noted by an improved score. The proportion of vessels in the "not seen" and "poorly seen" categories decreased from the initial scan (62.5%) to the scan utilizing the entire volume (36%). Alternatively, the percentage of vessels in the "adequately seen" to "well seen" categories improved from 37.50% on the initial examination to 64% on the scans using the entire volume to depict vascular anatomy. The optimal plane to image each vessel depended on the course of a specific vessel. For optimal imaging of all the selected vessels, both sagittal and transverse volume acquisitions and both sagittal and transverse planes were needed. Three-dimensional imaging provided a new imaging plane (coronal) that was useful in following and identifying vessels, especially those vessels coursing in a right to left direction. Vascular variants were identified by this technique in two of 16 subjects. Vascular imaging was improved with three-dimensional ultrasonography, and this imaging method may provide additional assistance in decision making when evaluating abdominal vessels.
Adult↗
Corneal endothelial damage by air bubbles during phacoemulsification.
OBJECTIVE: To characterize the mechanism by which air bubbles damage the corneal endothelium during phacoemulsification. MATERIALS AND METHODS: A series of experiments was conducted to expose the corneal endothelium of New Zealand white rabbit and human eyes that were obtained from an eye bank to air under different conditions. Phacoemulsification at different power settings and irrigation with and without the introduction of air into the anterior chamber were performed. Corneal endothelial perfusion experiments were conducted with air bubbles that were introduced into the perfusion chamber for 2 seconds to 1 hour. Air was also injected into the anterior chambers of anesthetized rabbits for 2 minutes to 3 hours. Corneas were stained with nitrobenzo-xadiazole-phallacidin and examined with fluorescence microscopy. Selected corneas were also examined with scanning and transmission electron microscopy. RESULTS: Intracameral air bubbles during phacoemulsification, irrigation, and perfusion studies resulted in a severe injury to the corneal endothelium in as little as 20 seconds. Intracameral air bubbles in a living rabbit resulted in a slower injury that was morphologically different from the more rapid injury. CONCLUSIONS: Air bubbles in intraocular fluids with a high surface tension can cause a ring-shaped pattern of damage to the corneal endothelium. The mechanism that caused this pattern of damage appears to be a surface tension phenomenon.
Air↗
Enhancement of thermostability and catalytic efficiency of AprP, an alkaline protease from Pseudomonas sp., by the introduction of a disulfide bond.
A site-directed mutagenesis in AprP, an alkaline protease isolated from Pseudomonas sp. KFCC 10818 was carried out in order to obtain increased thermostability. Sites for cysteine substitutions to form disulfide bond within AprP were chosen by comparing the sequences with aqualysin I, an alkaline thermostable serine protease whose disulfide bonds seems to be important for its thermostability. Gly199 and Phe236 residues were each replaced with cysteine by site-directed mutagenesis. The G199C/F236C mutant enzyme appeared to form a disulfide bond spontaneously during its expression. It also showed improved kinetic parameters for the hydrolysis of a synthetic peptide substrate at pH 8.5 and 10.5 compared to those of the wild-type enzyme. The half-life of the G199C/F236C mutant was found to be 2 to 4.8 times longer than that of wild-type under various experimental conditions, except when tested under reducing condition, where no significant differences in the half-life of the two types were observed. Therefore, it is concluded that the introduction of the disulfide bond enhanced the thermostability and the catalytic efficiency of the enzyme AprP.
Alkaline Phosphatase↗
A study on fetal urinary tract anomaly: antenatal ultrasonographic diagnosis and postnatal follow-up.
OBJECTIVE: To evaluate the incidence, associated anomalies, and the type of congenital urinary tract anomaly and to know the cause of congenital hydronephrosis. METHODS: In 4.5 years, 5,442 fetuses had ultrasonography and 48 cases of fetal urinary tract anomaly were detected. Ultrasonogram was done after delivery with further examination as necessary. RESULTS: The incidence of all types of anomaly was 4.3% (236/5,442) and the incidence of urinary tract anomaly was 0.9% (48/5,442, 8.8/1,000 births) of all babies born and 20.3% (48/236) of entire anomaly. Types of urinary tract anomaly were as follows; hydronephrosis (37 cases), multicystic dysplastic kidney (5 cases), polycystic kidney disease (2 cases), renal agenesis (2 cases), ectopic kidney (1 case) and hypoplastic kidney (1 case). Associated anomalies were found in 8 cases (16.7%) among 48. Causes of hydronephrosis were ureteropelvic obstruction in 13 cases, ureterovesical obstruction in 4 cases, vesicoureteral reflux in 2 cases, proximal ureteral obstruction in 2 cases, and no specific causes in 16 cases. CONCLUSIONS: Antenatal ultrasonography is a very useful diagnostic tool in the detection of urinary tract anomaly and a careful search for other anomalies is indicated when urinary tract anomaly is found.
Female↗
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↗
Section directed cryosectioning of specimens for scanning electron microscopy: a new method to study cardiac development.
A new method to study the developing heart was developed. Using this "section directed" cryosectioning method, appropriate fixed embryos can be trimmed optimally to obtain sectional planes that, if necessary, can be matched with histologically treated sections. As a result, the morphological information obtained with the scanning electron microscope can be compared in detail with the information on the molecular phenotypes of the subpopulations of cells as deducted from staining patterns of the sections. This method allows combination of the specific advantages of sophisticated histological techniques, such as immunohistochemistry and in situ hybridisation, with those of the scanning electron microscope.
Animals↗
Glutamate efflux from rat brain slices and cultures: a comparison of the depolarizing agents potassium, 4-aminopyridine, and veratrine.
The major excitatory amino acid neurotransmitter in the mammalian brain is glutamate (GLU). GLU release from nerve terminals is both calcium-dependent and -independent, yet these mechanisms of release are not fully understood. Potassium, 4-aminopyridine (4-AP) and veratrine are commonly used depolarizing agents that were studied for their ability to stimulate GLU efflux from brain slices. These agents produced significant regional variations in GLU efflux from rat brain slices. Potassium was the most potent of the three secretogogues tested. 4-AP produced a significant GLU efflux only in the cerebellum. Veratrine produced consistent stimulation of GLU efflux from all brain regions tested. Potassium was the only depolarizing agent tested that stimulated GLU release from primary astroglial cultures of rat cerebral cortex. All three agents also demonstrated an ability to inhibit GLU reuptake in brain slice preparations. This data suggest that both GLU release and uptake are modulated in a regionally selective manner, and that commonly used depolarizing agents affect not only calcium-dependent neuronal release, but also uptake and glial responses.
4-Aminopyridine↗
Characterization of 11 beta-hydroxysteroid dehydrogenase activity in fetal and adult ovine tissues.
11 Beta-hydroxysteroid dehydrogenase (11 beta-HSD) converts 11-hydroxycorticosteroids to 11-oxocorticosteroids, thereby influencing the availability of bioactive cortisol or corticosterone in target tissues. The activity of this enzyme was investigated in sheep by: (1) measuring relative 11 beta-HSD activities in kidney, liver and placenta, and in various areas of the brain (hypothalamus, hippocampus, and brainstem); (2) characterizing the optimum pH of activities in the tested tissues; (3) investigating the possible effect of gonadal steroids on 11 beta-HSD activity in adult hypothalamus and kidney; and (4) investigating possible developmental changes in activities in the tested tissues. The optimum pH in liver and placenta was pH 9-10, whereas the optimum pH in kidney was pH 7-8. In tissues from adult ewes, 11 beta-HSD activity was highest in liver (84.6 +/- 3.8%) and kidney (49.8 +/- 11.6%), lower but measurable in pituitary (38.8 +/- 3.7%), and near the limit of detection in hypothalamus and hippocampus (2.7 +/- 0.9% and 3.2 +/- 0.8% respectively). Liver, kidney and pituitary from late-gestation fetal sheep contained activities which were similar to those in the adult (76.9 +/- 4.5%, 66.0 +/- 6.7% and 26.3 +/- 3.0% respectively). Activity in the pituitary was not related to fetal gestational age. Placenta also contained measureable 11 beta-HSD activity (21.4 +/- 4.7%). However, no activity was detected in hypothalamus (-1.7 +/- 0.2%), hippocampus (-0.2 +/- 0.6%) or brainstem (-1.0 +/- 0.6%) in late-gestation fetal or neonatal sheep. Enzyme activities in kidney and hypothalamus did not change significantly when the circulating concentrations of ovarian steroids were altered over a 1-3-week period. It is concluded that the ovine kidney, liver and placenta, but not hypothalamus or cerebral cortex, contain 11 beta-HSD activity. In addition, there is no change in 11 beta-HSD activity between late-gestation fetal life and adult life, and the relative activities are not altered by the ovarian steroid milieu.
11-beta-Hydroxysteroid Dehydrogenases↗
Prenatal ultrasonographic diagnosis of congenital kyphosis due to anterior segmentation failure.
A few cases of congenital scoliosis due to segmentation failure have so far reported and the antenatal detection of pure congenital kyphosis without scoliosis due to segmentation failure has not been reported. We report the first prenatal identification using ultrasound of a fetus affected with pure congenital kyphosis due to anterior segmentation failure of the vertebral body between the second and third lumbar spine which was associated with ventriculomegaly, cleft palate, and hydramnios.
Adult↗
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↗
The 18S ribosomal RNA gene of an anthozoan Anthopleura kurogane: a comparison with Anemonia sulcata.
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Animals↗
Comparison of neural network and k-NN classification methods in medical image and voice recognitions.
We make a comparison of classification ability between BPN (Back Propagation Neural Network) and k-NN (k-Nearest Neighbor) classification methods. Voice data and patellar subluxation images are used. The result was that the average recognition rate of BPN was 9.2 percent higher than that of the k-NN classification method. Although k-NN classification is simple in theory, classification time was fairly long. Therefore, it seems that real time recognition is difficult. On the other hand, the BPN method is long in learning time but is very short in recognition time. Especially if the number of dimensions of the samples is large, it can be said that BPN is better than k-NN in classification ability.
Algorithms↗
Corneal endothelial cytoskeletal changes in F-actin with aging, diabetes, and after cytochalasin exposure.
We investigated the changes in endothelial cytoskeletal F-actin that occur with aging, diabetes, and exposure to cytochalasin D. Rabbit corneas, human donor corneas (with or without polymegethism), and corneas of diabetic individuals were studied. Endothelial F-actin was stained using nitrobenzoxadiazole-phallacidin. Results of these experiments demonstrated that F-actin of the rabbit and human corneal endothelium was arranged in linear circumferential strands that formed a hexagonal array. After in vitro perfusion of cytochalasin D to the corneal endothelium, the F-actin became randomly distributed throughout the cytoplasm, the hexagonal shape of the endothelial cell was disrupted, and endothelial permeability to carboxyfluorescein increased. Changes in F-actin were also observed in the endothelium of the human corneas with polymegethism, and in donor tissue having had previous posterior chamber intraocular lens implantation. The corneas of diabetic individuals also showed marked irregular F-actin fibers crossing the endothelial cell cytoplasm. These abnormal patterns of F-actin may contribute in part to the polymegethism observed in the corneal endothelial cells and may be the result of constant stress in cell volume regulation, particularly in the corneas of diabetic individuals.
Actins↗
An in vitro model to test relative antioxidant potential: ultraviolet-induced lipid peroxidation in liposomes.
Since antioxidants have been shown to play a major role in preventing some of the effects of aging and photoaging in skin, it is important to study this phenomenon in a controlled manner. This was accomplished by developing a simple and reliable in vitro technique to assay antioxidant efficacy. Inhibition of peroxidation by antioxidants was used as a measure of relative antioxidant potential. Liposomes, high in polyunsaturated fatty acids (PUFA), were dispersed in buffer and irradiated with ultraviolet (UV) light. Irradiated liposomes exhibited a significantly higher amount of hydroperoxides than liposomes containing antioxidants in a dose- and concentration-dependent manner. Lipid peroxidation was determined spectrophotometrically by an increase in thiobarbituric acid reacting substances. To further substantiate the production of lipid peroxides, gas chromatography was used to measure a decrease in PUFA substrate. In order of decreasing antioxidant effectiveness, the following results were found among lipophilic antioxidants: BHA greater than catechin greater than BHT greater than alpha-tocopherol greater than chlorogenic acid. Among hydrophilic antioxidants, ascorbic acid and dithiothreitol were effective while glutathione was ineffective. In addition, ascorbic acid was observed to act synergistically with alpha-tocopherol, which is in agreement with other published reports on the interaction of these two antioxidants. Although peroxyl radical scavengers seem to be at a selective advantage in this liposomal/UV system, these results demonstrate the validity of this technique as an assay for measuring an antioxidant's potential to inhibit UV-induced peroxidation.
Antioxidants↗
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↗