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Biomedical subjects

J H Choi

Publications and source records attributed to J H Choi.

At least 91 records · Page 5Linked to original sources
PubMed2001

Idiopathic eruptive macular pigmentation: report of 10 cases.

Idiopathic eruptive macular pigmentation (IEMP) is a rare disease. IEMP is characterized by asymptomatic, pigmented macules involving the neck, trunk, and proximal extremities. This study describes 10 cases of idiopathic eruptive macular pigmentation seen during a 9-year period at the Asan Medical Center, Seoul, Korea. We present these characteristic consecutive cases to provide more insight into the clinical picture and course of IEMP. Skin lesions of 8 patients were multiple brown macules involving the trunk, face, neck, and extremities. In 2 patients, multiple dark brown macules and patches were noted. The age of onset varied from 1 to 20 years. Tentative diagnoses were usually ashy dermatosis (erythema dyschromicum perstans), fixed drug eruption, or mastocytosis. The history of any erythema and drug medication was absent. Darier's sign was absent. Skin biopsy specimens showed increased pigmentation of the basal layer in an otherwise normal epidermis. Pigmentary incontinence, melanophages, and mild perivascular lymphohistiocytic infiltrate in the papillary dermis were also revealed. Mast cells could not be found. The lesions gradually disappeared during a period of several months to years. The alleged rarity of IEMP may be partially caused by medical unfamiliarity with this entity, despite its clinical and histopathologic characteristic picture. Treatment of IEMP is unnecessary because spontaneous resolution of the lesions can be expected within several months to a few years.

Adolescent↗
PubMed2001

Distortion product otoacoustic emissions in diabetics with normal hearing.

In 18 diabetic patients with normal hearing, distortion product otoacoustic emissions (DPOAEs) were measured. DPOAEs' amplitude and latency were analysed and compared with the data obtained from non-diabetic controls. The mean amplitude and latency were lower in diabetics than in controls. These results suggested that diabetes mellitus may induce the functional alteration of outer hair cells even in the normal hearing group. Further studies should be performed to evaluate the predictability of DPOAEs in hearing loss of the diabetic patient.

Adult↗
PubMed2001

Application of synthetic poly(DADM) flocculants for dye wastewater treatment.

Poly(DADM) flocculants were synthesized and applied for the removal of color, turbidity and organic materials from dye wastewater. The effect of poly(DADM) on color removal was investigated by comparing two treatments: (i) alum alone and (ii) alum/poly(DADM) in combination. The effects of poly(DADM) flocculant, poly(DADM) concentration, poly(DADM) types and pH on the removal efficiency of coloring materials were investigated. Poly(DADM) flocculants were highly efficient in the removal of color and turbidity from dye wastewater. Compared to treatment with alum alone, the addition of a small amount of poly(DADM) (25 mg l(-1)) reduced alum dosage by 50% while improving color removal efficiency. Highly efficient color removal was obtained in wide pH ranges by adding poly(DADM) as a flocculant. Our results indicate that the use of poly(DADM) flocculant is cost effective in dye wastewater treatment by reducing sludge production and the dosage of inorganic coagulant. Effects of zeta potential were also investigated.

Coloring Agents↗
PubMed2001

Vitamin E improves microsomal phospholipase A2 activity and the arachidonic acid cascade in kidney of diabetic rats.

The purpose of the present study was to investigate the effects of vitamin E on microsomal phospholipase A2 activity and the arachidonic acid cascade in the kidneys of streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley male rats weighing 100 +/- 10 g were randomly assigned to one normal and three STZ-induced diabetic groups. The diabetic groups were fed a vitamin E-free diet (the DM-0E group), 40 mg vitamin E/kg diet (the DM-40E group) or a 400 mg vitamin E/kg diet (the DM-400E group). The kidney vitamin E concentrations were 59 and 49% lower in the DM-0E and DM-40E groups, respectively, than in the normal group. The kidney thiobarbituric acid reactive substance concentrations in the DM-0E, DM-40E and DM-400E groups were 119, 84 and 33% greater, respectively, than that in the normal group. The concentration in the DM-400E group was 39% lower than that in the DM-0E group. The phospholipase A2 (PLA2) activity in the kidney microsomes of the DM-0E-40E and DM-400E groups were 88, 58 and 35% greater, respectively, than that in the normal group. The activity in the DM-400E group was 28% lower than that in the DM-0E group and 16% lower than that in the DM-40E group. The differences in the phospholipids in the kidney microsomes included reductions in the phosphatidylcholine and phosphatidylethanolamine compositions. Phosphatidylethanolamine hydrolysis in the kidney microsomes of the DM-0E and DM-40E groups were 84 and 64%, which did not differ from the DM-400E group. The formation of thromboxane A2 (TXA2) in the kidney microsomes was 137 and 70% greater in the DM-0E and DM-40E groups, respectively, than in the normal group. TXA2 formation did not differ between the DM-400E and normal groups. The formation of prostacyclin in the kidney microsomes was 60 and 44% lower in the DM-0E and DM-40E groups, respectively, than in the normal group, whereas the DM-400E group did not differ from that in the normal group. The ratio of prostacyclin to TXA2 was 82 and 65% lower than normal in the DM-0E and DM-40E groups, respectively. Kidney function appears to be improved by vitamin E supplementation due to its antithrombus action, which in turn controls the arachidonic acid cascade system.

Animals↗
PubMed2001

Glucocorticoid-mediated repression of inflammatory cytokine production in fibroblast-like rheumatoid synoviocytes is independent of nuclear factor-kappaB activation induced by tumour necrosis factor alpha.

OBJECTIVE: To determine whether steroids inhibit the production of inflammatory cytokines by the inhibition of nuclear factor kappaB (NF-kappaB) activation in fibroblast-like rheumatoid synoviocytes (FLSs) under inflammatory conditions, and to determine whether steroids stimulate the induction of synthesis of the inhibitory protein IkappaB-alpha in the anti-inflammatory immune response of these cells. METHODS: Expression of the interleukin-6 (IL-6) and interleukin-1beta (IL-1beta) genes was measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), and the secreted IL-6 was measured with the enzyme-linked immunosorbent assay. Inhibition of the NF-kappaB activation was examined with the electrophoretic mobility shift assay (EMSA). In order to study dexamethasone (DEX)-dependent regulation of IkappaB-alpha expression, we performed Western blotting before and after stimulation with tumour necrosis factor alpha (TNF-alpha). RESULTS: The inflammatory cytokine study showed that DEX suppressed gene expression and the production of protein in FLSs. EMSA demonstrated that identical amounts of NF-kappaB were present in the nucleus of the FLSs stimulated by TNF-alpha, with or without pretreatment with DEX. Treatment of FLSs with DEX did not induce an increase in IkappaB-alpha sufficient to prevent nuclear translocation of NF-kappaB on stimulation with TNF-alpha. CONCLUSION: DEX may suppress the production of inflammatory cytokines, such as IL-6 and IL-1beta, but it neither prevents the translocation of NF-kappaB to the nucleus nor induces the synthesis of IkappaB-alpha protein in FLSs stimulated by TNF-alpha.

Arthritis, Rheumatoid↗
PubMed2001

A case of juvenile xanthogranuloma arising on a nevus sebaceus.

Various epithelial and mesenchymal neoplasms can arise in nevus sebaceus (NS). Juvenile xanthogranuloma arising on an NS has not been reported previously. Juvenile xanthogranuloma, a disease characterized by reactive histiocytic proliferation, could be included in the list of secondary alterations arising on an NS.

Adolescent↗
PubMed2001

Laser blepharoplasty for making double eyelids in Asians.

The double-eyelid operation is a cosmetic procedure performed primarily on Asians who have no supratarsal folds. The goal in Oriental blepharoplasty is to ensure a stable double-eyelid fold with predictable and long-lasting results. Candidates for this procedure desire attractive eyelids with a natural-looking fold. Today, the CO2 laser is used as a surgical tool by plastic surgeons, and its use in cosmetic surgery has recently been expanded to blepharoplasties. We used the high-power CO2 laser (UltraPulse; Coherent, Santa Clara, Calif.) in the double-eyelid operation. Between September of 1995 and September of 1999, a total of 241 patients underwent laser double-eyelid operations at Korea University Medical Center and Dr. Choi's Aesthetic Clinic, with an average follow-up of 18 months. By using the CO2 laser, we could create a stable double-eyelid fold with long-lasting results. The rate of fold release was 2 percent, which was less than the rate using the conventional scalpel incision method. The CO2 laser contributed to a reduction in pain or discomfort after the operation; therefore, patient comfort and early recovery could be enhanced after double-eyelid surgery. In the healing of the incision line, it showed mild redness for 3 weeks, but long-term follow-up showed the scar produced by the laser appeared to be equal in quality compared with the conventional method. Laser blepharoplasty is a useful and effective method to create a stable and attractive double eyelid for Asian patients.

Adolescent↗
PubMed2001

Clinicohistopathologic comparison of adult type and juvenile type xanthogranulomas in Korea.

Xanthogranuloma (XG) is an uncommon benign disorder characterized by solitary or multiple yellow-red papulonodules on the skin, and occasionally, in other organs. It is predominantly a disease of infancy or early childhood, although adults may rarely be affected. To compare the clinicohistopathological featues of juvenile-type xanthogranulomas UXGs) and adult-type xanthogranulomas (AXGs) (>14 years) in Korea, 30 cases of JXGs and 15 cases of AXGs were compared clinically and histopathologically. Except for the fact AXGs were more often solitary and larger and showed neither other associated systemic diseases nor spontaneous regression, the clinical features such as color, mean number, or site of the lesions in AXGs were not statistically different from JXGs. Histologically, AXCs were not significantly different in amounts of foamy cells, giant cells including Touton cells, and inflammatory cells, although subcutaneous involvement was seen only in the two infant cases. In conclusion, in contrast to AXGs, JXGs need special attention to accompanying systemic diseases and do not need excisional procedures, considering their frequent spontaneous regression.

Adolescent↗
PubMed2001

Chronic tophaceous gout presenting as hyperpigmented nodules in the limbs of a patient with coexisting psoriasis.

We describe a 53-year-old male renal transplant recipient with hypertension and triglyceridemia, who showed rare manifestations of gout presenting as brownish nodules on the arms and legs as well as chronic tophaceous gouty arthritis of the hands and feet mimicking rheumatoid arthritis, in association with subsequently developed psoriasis of the palms. In elderly Asian men, hypertension and renal insufficiency may be risk factors predisposing to the development of multiple hyperpigmented nodules of tophi in the more proximal extremities.

Arm↗
PubMed2001

A case of cutaneous low-grade myofibroblastic sarcoma.

A 28-year-old woman presented with a recurrent nodule on the lower margin of her left nostril after laser surgery. Histologically, the nodule had an indistinct margin and was composed of interlacing fascicles of plump, spindled or stellate tumor cells with mild cytologic atypia. The tumor cells were revealed to be myofibroblasts by positivity to smooth muscle actin and negativity to desmin. A diagnosis of low grade myofibroblastic sarcoma (LGMS) was made.

Actins↗
PubMed2001

Expression profile of histone deacetylase 1 in gastric cancer tissues.

Although histone deacetylases (HDACs) appear to play a crucial role in carcinogenesis, the expression status of HDACs in primary human cancer tissues has not yet been reported. In this study, we investigated the expression level of HDAC1 in 25 paired primary human gastric cancer (GC) tissues and corresponding normal tissues through semi-quantitative RT-PCR and immunoblot analysis. The HDAC1 expression pattern was also topologically examined through immunohistochemistry. Overexpression of HDAC1 mRNA was detected in 68% of GC tissues (17 of 25), and the relative density of HDAC1 mRNA in GC tissue was increased 1.8-fold versus the normal counterpart (P < 0.01). Elevated expression of HDAC1 protein was also detected in 61% of GC samples (11 of 18), which also showed an increased mRNA level of HDAC. Immunohistochemically, overexpression of HDAC1 was predominantly localized in the nuclei of most neoplastic cells, including embolic tumor cells, whereas normal glandular epithelial cells revealed only weak HDAC1 expression that was focal in distribution. Thus, the present study clearly demonstrates that HDAC1 is overexpressed in GC and probably plays a significant role in gastric carcinogenesis.

Blotting, Western↗
PubMed2001

Investigation of human brain hemodynamics by simultaneous near-infrared spectroscopy and functional magnetic resonance imaging.

The aim of this study was to compare functional cerebral hemodynamic signals obtained simultaneously by near infrared spectroscopy (NIRS) and by functional magnetic resonance imaging (fMRI). The contribution of superficial layers (skin and skull) to the NIRS signal was also assessed. Both methods were used to generate functional maps of the motor cortex area during a periodic sequence of stimulation by finger motion and rest. In all subjects we found a good collocation of the brain activity centers revealed by both methods. We also found a high temporal correlation between the BOLD signal (fMRI) and the deoxy-hemoglobin concentration (NIRS) in the subjects who exhibited low fluctuations in superficial head tissues.

Brain↗
PubMed2001

Tectorigenin, an isoflavone of Pueraria thunbergiana Benth., induces differentiation and apoptosis in human promyelocytic leukemia HL-60 cells.

Cytotoxic effects of six isoflavonoids, tectorigenin, glycitein, tectoridin, glycitin, 6''-O-xylosyltectoridin, and 6''-O-xylosylglycitin isolated from the flower of Pueraria thunbergiana Benth. together with genistein, a known differentiation and apoptosis inducer, were examined. Among these isoflavonoids, tectorigenin and genistein exhibited cytotoxicity against various human cancer cells; glycitein showed only mild cytotoxicity. These results suggest that the isoflavone structure and 5-hydroxyl group are crucial for the cytotoxic properties and that glycosides are inactive. Moreover, tectorigenin induced differentiation of human promyelocytic leukemia HL-60 cells to granulocytes and monocytes/macrophages, and caused apoptotic changes of DNA in the cells, as did genistein. Tectorigenin also inhibited autophosphorylation of epidermal growth factor (EGF) receptor by EGF and decreased the expression of Bcl-2 protein, with less activity than genistein. From these results, tectorigenin may be a possible therapeutic agent for leukemia.

Anti-Inflammatory Agents, Non-Steroidal↗