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Biomedical subjects

H Y Choi

Publications and source records attributed to H Y Choi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Diagnostic efficacy of fluorescence cystoscopy for detection of urothelial neoplasms.

BACKGROUND AND PURPOSE: A major problem diagnosing bladder cancer using conventional white-light cystoscopy is that flat and tiny papillary neoplasms can be overlooked. Fluorescence cystoscopy is based on the detection of protoporphyrin IX (PpIX)-induced fluorescence in urothelial neoplasms through the topical administration of 5-aminolevulinic acid (ALA). The diagnostic efficacy of fluorescence cystoscopy in urothelial neoplasms was evaluated in this study. The focus of this investigation was to ascertain whether fluorescence cystoscopy could make a major contribution to staging and improving the choice of adjuvant therapy after transurethral resection. PATIENTS AND METHODS: A series of 62 patients with suspected bladder cancer were investigated by fluorescence cystoscopy. An intravesical instillation of ALA was conducted 2 hours prior to fluorescence. A total of 274 tissue samples were obtained from the fluorescing and nonfluorescing areas of the bladder. RESULTS: The sensitivity and negative predictive value of fluorescence cystoscopy were 98.0% and 94.7%, respectively, but the specificity was low (42.9%). Among a total of 148 lesions of urothelial neoplasm, 58 foci (dysplasia in 5, carcinoma in situ in 19, stage Ta in 15, T1 in 15, above T2 in 4) that were invisible under white-light cystoscopy were detected by fluorescence cystoscopy. The final histopathologic status was changed in 45% of patients (28/62) according to this technique. Among these patients, eight (13%) needed additional therapy, including a radical cystectomy in one patient and intravesical therapy in 10. CONCLUSIONS: The ALA-based fluorescence cystoscopy technique is a safe and simple procedure that enhances the detection of flat and papillary urothelial neoplasms. Moreover, it will be able to provide useful information that will enable proper staging and appropriate further treatment.

Adult↗
PubMed2001

Five cases of microphthalmia with other ocular malformations.

We report five cases of complex microphthalmia with other ocular malformations in infants or children, which were evaluated to investigate the relationship between the corneal diameters and total axial length. The size of the globe was measured by using computerized tomographic scans (CT scan), A-scan ultrasonography, or magnetic resonance imaging (MRI). There is a limited range of well-described malformation, including anterior or posterior segment dysgenesis or combined pathology such as corneal opacity, small cornea, iris hypoplasia, lens dislocation, cataract, chorioretinal coloboma, persistent hyperplastic primary vitreous (PHPV), retinal dysplasia, and intraocular tumor. Corneal diameters were correlated significantly with total axial length (r2 = 0.88) and decreased linearly as the total axial length decreased in these cases. However, there was no relationship seen between the total axial length and posterior segment length (r2 = -0.06). The results of this study may aid the clinical ophthalmologist to accurately understand or assess microphthamia combined with other ocular malformations.

Abnormalities, Multiple↗
PubMed2001

Infantile hemangioendothelioma treated with high dose methylprednisolone pulse therapy.

Infantile hemangioendothelioma is a severe disease with a high mortality. It is characterized by multiple hemangioma affecting the skin and visceral organs. We report that high doses of methylprednisolone pulse therapy improved symptoms and signs of infantile hemangioendothelioma in a male neonate, and completely resolved the hepatic and cutaneous hemangioendothelioma on follow up.

Hemangioendothelioma↗
PubMed2001

Generalized seborrheic dermatitis in an immunodeficient newborn.

We report the case of a female infant with failure to thrive, generalized seborrheic dermatitis, and intermittent diarrhea. Results of laboratory investigation revealed low serum immunoglobulin G IgG levels. She failed to gain additional weight and experienced recurrent infection. She died 3 months later.

Dermatitis, Seborrheic↗
PubMed2000

The effects of ascorbic acid on dopamine-induced death of PC12 cells are dependent on exposure kinetics.

The role of ascorbic acid on dopamine (DA) oxidation-mediated cytotoxicity was studied using the PC12 cell line. DA cytotoxicity was slightly attenuated by ascorbic acid, whereas the cytotoxicity of 6-hydroxydopamine (6-OHDA), a DA oxidation product, was markedly potentiated. To elucidate the relationship between the ascorbic acid effect and the degree of DA oxidation, ascorbic acid was added in a time-dependent fashion after DA treatment. We found greater cell death the later ascorbic acid was applied. Treatment of cells with glutathione alleviated DA- and 6-OHDA-induced cell death, while L-buthionine sulfoximine potentiated DA and 6-OHDA cytotoxicity. Ascorbic acid combined with glutathione eliminated the toxicity of DA and 6-OHDA. These results suggest that the interaction between DA and ascorbic acid is dependent upon the degree of DA oxidation and glutathione availability.

Animals↗
PubMed2000

Angiopoietin-1 inhibits irradiation- and mannitol-induced apoptosis in endothelial cells.

BACKGROUND AND PURPOSE: Angiopoietin-1 (Ang1) is a vasculogenic factor that signals through the endothelial cell-specific Tie2 receptor tyrosine kinase. We recently reported that Ang1 prevented apoptosis induced by serum deprivation in endothelial cells. In this study, we examined whether Ang1 prevents apoptosis in endothelial cells treated with irradiation or clinical concentrations of mannitol. METHODS AND RESULTS: ++Ang1 prevented irradiation- and mannitol-induced apoptosis in human umbilical vein endothelial cells in a dose-dependent manner. Pretreatment with soluble Tie2 receptor, but not Tie1 receptor, blocked the antiapoptotic effect of Ang1. Two phosphatidylinositol 3'-kinase (PI3-kinase)-specific inhibitors, wortmannin and LY294002, blocked the Ang1-induced antiapoptotic effect. The antiapoptotic potency of Ang1 was similar to or greater than that of vascular endothelial growth factor, basic fibroblast growth factor, and endothelin-1. Ang1 also prevented apoptosis in cultured endothelial cells from porcine pulmonary and coronary arteries and in endothelial cells of explanted rat aorta. CONCLUSIONS: Ang1 promotes the survival of endothelial cells in irradiation- and mannitol-induced apoptosis through Tie2 receptor binding and PI3-kinase activation. Pretreatment with Ang1 could be beneficial in maintaining normal endothelial cell integrity during intracoronary irradiation or systemic mannitol therapy.

Angiopoietin-1↗
PubMed2000

Application of flow injection--chemiluminescence to the study of radical scavenging activity in plants.

Chemiluminescence (CL) was observed during the oxidation of luminol (2 mg/L). mediated by 0.06% hydrogen peroxide (H(2)O(2)) and cytochrome c (10 mg/L). CL intensity was decreased by the presence of radical scavengers and the reduction was linearly proportional to the concentration and ability of scavengers; butylated hydroxytoluene (BHT), caffeic acid and gallic acid. The order of effectiveness as radical scavengers was gallic acid > caffeic acid > BHT, which shows that the number of hydroxyl groups (OH) in the B-ring of flavonoids plays a key role in a good radical scavenging activity. Of eight catechins obtained from green tea extracts, (-)-catechin was the least effective and (-)-epigallocatechin gallate (EGCg) showed the strongest activity. This result indicates that the stereoscopic structure between the C-3 group and the B ring of flavonoids as well as substituents at the C-3 position make a contribution to radical scavenging activity. Of the tested Chinese herbal ingredients, five species of ingredients represented more than 90% of the radical scavenging activity.

Butylated Hydroxytoluene↗
PubMed2000

A new method for aesthetic reduction of labia minora (the deepithelialized reduction of labioplasty).

An enlarged labium minus can be bothersome for functional, aesthetic, and social reasons. Labia minora hypertrophy can be congenital or acquired by chronic irritation, exogenous androgenic hormones, or stretching with weights. This can cause inflammation, poor hygiene, interference with sexual intercourse, or intermittent urinary self-catheterization in myelodysplastic women. Aesthetically, an asymmetric or enlarged labium minus causes self-consciousness sexually and when the subject wears tight pants. Previously, labia minora reduction was performed by amputation of the protuberant segment and oversewing the edge, or a wedge of protuberant labial tissue was excised and reapproximated. However, the former technique removes the natural contour and color of the edge of the labium minus, and the latter can result in an incomplete or tight reduction. Therefore, rather than an amputation or a wedge resection, we preserved the natural contour and anatomy of the labium minus by simply reducing its central width through bilateral deepithelialization and reapproximation of the central portion with preservation of the neurovascular supply to the edge. Six patients have undergone this reduction method with excellent results without specific complications.

Adolescent↗
PubMed2000

Pancreatic serous cystadenoma associated with islet cell tumour.

We report the case of a 29-year-old female patient with a diffuse type of serous cystadenoma involving the entire pancreas except for part of the head, which was replaced by islet cell tumour. Ultrasound and CT showed multiple cysts in the entire pancreas and a solid mass with calcification in the head. MRI characterized the fluid content of the cysts and the extent of disease.

Adult↗
PubMed2000

Change of spontaneous reaction of glue and lipiodol mixture during embolization after the addition of tungsten powder: in vitro study.

BACKGROUND AND PURPOSE: We have noted that glue-Lipiodol mixtures harden prematurely in the catheter during embolization of brain arteriovenous malformations. However, we observed that hardening of this embolic material does not occur when tungsten powder is added to the glue mixture. In order to clarify the effect of tungsten powder on the glue mixture, we evaluated the reaction time and hardness of the glue mixture in vitro after the addition of tungsten powder. We also measured the pH of the tungsten solution. METHODS: Six lots of Lipiodol and three lots of Histoacryl Blue were mixed in a 5-cc bottle with a 50% to 25% glue concentration (glue:Lipiodol = 1:1 to 1:3) and this mixture was observed for 2 weeks. The hardness of the polymerized glue mixture was categorized as liquid, gel, semi-solid, or solid. Various series of experiments were performed after the addition of tungsten powder (0.2 g) and blood (a drop) into the glue mixture. We also separately mixed tungsten and tantalum powder in tubes, each with 5 mL of distilled water, and then measured the pH of these three times. The mixed amounts of tungsten and tantalum ranged from 0.1 to 0.5 mg. RESULTS: In a 50% glue concentration, the glue mixture turned into a solid cast within 48 hours. In a 25% concentration, the glue mixture turned into gel within 24 hours. The casts became solid in the 50% and gelled in the 25% concentration, and solid or gel in 28% and 33% glue mixture concentrations. The addition of tungsten powder to 50% and 25% glue mixture concentrations caused the glue mixtures to remain in a liquid state for 2 weeks regardless of the Lipiodol products used. Measurement of acidity achieved using a pH meter in 5 cc of distilled water with tungsten powder (0.1 to 0.5 g) revealed a change of pH from 3.5 to 2.6 according to the amount of tungsten added. Tantalum revealed weak acidity, with a pH range from 6.4 to 5.7. The addition of blood immediately caused the mixture to become solid in 50% and semi-solid in 25% glue concentrations. CONCLUSION: The reaction time of the glue mixture differed according to the lot number of the Lipiodol. The addition of tungsten powder appeared to prevent premature cast formation by decreasing the pH with a mechanism similar to that of adding acetic acid.

Chemical Phenomena↗
PubMed1999

Immune responses to Aspergillus antigen in IL-4-/-mice and the effect of eosinophil ablation.

BACKGROUND: Exposure to Aspergillus fumigatus allergens results in enhanced total serum IgE and peripheral blood eosinophils in mice. The associated pulmonary inflammation and immunologic responses are comparable to those detected in human allergic bronchopulmonary aspergillosis. Allergen-induced cytokines are thought to regulate the inflammatory and immune responses in these animals. METHODS: In the present study, we exposed C57BL/6 and BALB/c mice to A. fumigatus antigen. Both wild-type and IL-4 knockout phenotypes of animals of both strains were used. Some animals were also treated with anti-IL-5 or anti-IFN-gamma. Total serum IgE, Aspergillus species IgG subclass, peripheral blood eosinophils, and lung histology were studied. RESULTS: The results demonstrate similar lung inflammation in all wild-type and IL-4-/- animals exposed to A. fumigatus antigen. Similarly, in spite of the diverse immune response produced by the anticytokine treatment, no major differences were detected among any of the animal groups studied. CONCLUSIONS: It can be concluded that A. fumigatus exposure in an immunologically unaltered host is predominantly of a Th2 type, and that depletion of the Th2 cytokine leads to a similar lung inflammation but with a characteristic Th1 response, suggesting that the pathogenesis of allergic aspergillosis is the result of multiple induction pathways.

Animals↗
PubMed1999

Long-term comparison of a newly designed gold implant with the conventional implant in facial nerve paralysis.

Patients with complete facial nerve palsy are at risk for eye complications resulting from exposure of the cornea and loss of the blinking reflex. Failure of protection predisposes the patient to exposure keratitis, corneal abrasion and, in rare cases, blindness. The mainstays of non-surgical therapy are cumbersome, obscure vision, and are mostly helpful in patients with acute facial paralysis in whom recovery of orbicularis oculi function is expected. Methods of lid-loading using metal implants and gold eyelid weights have been reported in the literature. Between October of 1988 and March of 1995, 32 patients with lagophthalmos due to facial nerve palsy underwent a total of 34 procedures for the insertion of a gold eyelid weight. Each patient had a gold weight inserted into a small pocket between the orbicularis oculi and the tarsal plate of the upper eyelid. The gold implant is curved to fit the curvature of the eye and contains holes for fixation to the tarsus with sutures. Ingrowth of fibrous tissue through the holes may also help fix the weight in position. Between 1988 and 1991, 10 patients received 10 commercially available rectangular gold implants with 2 holes; these implants resulted in adverse effects, such as infection and exposure in up to 30 percent of the cases. Because of the high complication rate with the rectangular gold implant, the authors began using a new, elliptical gold implant with 3 holes, which is longer, thinner, wider in the center, and narrower in the peripheral portion. This new elliptical implant was used on 22 patients (24 implants) from December of 1991 through March of 1995. The mean follow-up time for the 32 patients in the study was 41.3 months (range, 6 to 63 months), 49.8 months for patients with rectangular implants and 32.8 months for patients with elliptical implants. The elliptical gold implant resulted in dynamic closure of the eyelid and in excellent protection and cosmesis. Lagophthalmos and exposure keratitis resolved, visual acuity significantly improved without complications, and most patients could dispense with eyedrops and salves. A lower eyelid supporting procedure (conchal cartilage graft) should be performed simultaneously in patients with lagophthalmos of a moderate or severe degree to achieve complete closure of the eyelid. Use of a tall pillow decreased the incidence of eyelid opening during sleep. Double eyelid fold operations'were performed on the contralateral eyelid after 6 months, resulting in a symmetrical and beautiful eyelid.

Adolescent↗
PubMed1999

Intraoperative radio-guided identification of parathyroid adenomas with the gamma probe: initial experiences in a community hospital.

Previous radiological imaging studies for identification of parathyroid adenomas have generally been unreliable. Currently, preoperative administration of Tc-99m sestamibi improves detection of parathyroid adenomas. Combining preoperative administration of sestamibi radionuclide with the gamma probe intraoperatively can successfully identify the exact location of parathyroid adenomas in a community hospital setting and facilitate a safe and efficient operation. A team approach, including surgeon, radiologist, and technologist, is recommended to facilitate mastery of the learning curve.

Adenoma↗
PubMed1998

Long-term follow-up of cranial bone graft in dorsal nasal augmentation.

A follow-up of 363 cranial bone grafts for nasal reconstruction is presented. The main indications for the surgery were congenital, posttraumatic, or postrhinoplasty deformity. The results were satisfactory in the vast majority of cases. The complications associated with the grafts and with the donor site are discussed, as are the methods to treat and prevent these complications from occurring.

Adult↗
PubMed1996

Minimally differentiated acute myelogenous leukemia presented with multiple cervical lymphadenopathy.

Lymphadenopathy is a relatively uncommon finding of minimally differentiated acute myelogenous leukemia (AML-MO). We experienced a case of AML-MO in a 57-year-old man initially presented with multiple cervical lymphadenopathy. Bone marrow aspiration revealed myeloblasts, which were negative for myeloperoxidase, Sudan black B, Periodic acid-Schiff, non-specific esterase and double esterase reaction. In cell surface marker studies, CD13, CD14, CD33, CD34, CD45 and HLA-DR were present. CT scan of neck demonstrated multiple lymphadenopathy at both internal jugular chains, spinal accessory chains and submandibular area. He died about two weeks after diagnosis without specific treatment.

Fatal Outcome↗