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Biomedical subjects

H Y Kim

Publications and source records attributed to H Y Kim.

At least 91 records · Page 5Linked to original sources
PubMed2000

Development of a newly designed double-fixed Seoul-type keratoprosthesis.

OBJECTIVE: To develop a newly designed double-fixed keratoprosthesis (Seoul-type keratoprosthesis [S-KPro]) and to assess its mechanical stability and biocompatibility. METHODS: Twenty-five rabbits were divided into 4 groups by fixation technique, amniotic membrane (AM) implantation, and skirt material. The eyes were studied with the use of slitlamp, light, and electron microscopy. Stress testing was performed. In addition, 2 human subjects underwent S-KPro implantation. Best-corrected visual acuity was checked, and ophthalmic examination was performed. RESULTS: The average retention period of the group receiving double-fixated polyurethane-S-KPro with AM was longer (>24 weeks) than that of the others. Fibroblast invasions were found in polyurethane pores but not in polytetrafluoroethylene (Gore-Tex) pores on light microscopy. The minimal pressure that induced aqueous leakage was greater than 250 mm Hg in all of the tested eyes. Two human subjects have maintained a good postoperative condition for 18 and 8 months. CONCLUSIONS: The double-fixation technique of applied S-KPro and AM appears to be helpful in improving the stability of the keratoprosthesis. Polyurethane with relatively large pore size (40 microm) may be used successfully as a material for the keratoprosthesis skirt. CLINICAL RELEVANCE: Our results may be important for improving the clinical outcome of keratoprosthesis.

Adult↗
PubMed2000

Accumulation of docosahexaenoic acid in phosphatidylserine is selectively inhibited by chronic ethanol exposure in C-6 glioma cells.

Neuronal membranes are highly enriched with docosahexaenoic acid (22:6n-3), and its content can be altered by ethanol consumption. We have previously reported that the 22:6n-3 status in membrane affects the biosynthesis of phosphatidylserine (PS), a phospholipid class which contains an exceptionally high proportion of 22:6n-3. The aim of the present study is to investigate the effect of chronic ethanol exposure on PS accumulation in relation to the 22:6n-3 status. C-6 glioma cells were enriched with 25 microM 22:6n-3 for 48 h and the PS accumulation was first evaluated in comparison to nonenriched cells as well as cells enriched with arachidonic acid (20:4n-6). Electrospray liquid chromatography-mass spectrometry analysis revealed that cells treated with 22:6n-3 showed significantly higher accumulation of PS in comparison to nonenriched or 20:4n-6-enriched cells, primarily due to an increase of 1-stearoyl-2-docosahexaenoyl-glycerophosphoserine (18:0,22:6-PS). Chronic ethanol exposure selectively affected the accumulation of PS in 22:6n-3-enriched cells. After cells were exposed to 20 or 50 mM ethanol for 4 wk, accumulation of 18:0,22:6-PS upon 22:6n-3 supplementation was significantly lower, resulting in a drastic reduction of total PS. Concomitantly, ethanol-treated cells showed lower incorporation of serine in comparison to control cells. From these data, it was concluded that supplementation of cells with 22:6n-3 promotes the accumulation of PS and chronic ethanol treatment diminishes this effect at least in part through impaired serine incorporation processes. Attenuated accumulation of 22:6n-3 in PS and the reduction of PS thus may have significant implications in pathophysiological effects of ethanol, especially in tissues with abundant 22:6n-3.

Animals↗
PubMed2000

Furanocoumarins from the root of Angelica dahurica.

Five furanocoumarins including a new one were isolated from the root of Angelica dahurica by repeated silica gel column chromatography. Their chemical structures were determined to be isoimperatorin (1), oxypeucedanin hydrate-3"-butyl ether (2), imperatorin (3), knidilin (4), and oxypeucedanin hydrate (5). This represents the first study in which the compound 2 has been isolated and identified. The long-range coupling (5J) in the 1H-NMR spectrum observed in the linear furanocoumarin skeleton was also investigated in detail.

China↗
PubMed2000

Comparison of 2,4,6-trinitrotoluene degradation by seven strains of white rot fungi.

The degradation of 2,4,6-trinitrotoluene (TNT) by seven strains of white rot fungi was examined in two different media containing 50 mg L(-1) of TNT. When TNT was added into a nutrient-rich YMG medium at the beginning of the incubation, four of the fungal strains completely removed TNT during several days of incubation and showed higher removal rates than those of Phanerochaete chrysosporium. TNT added into YMG medium after a 5-day preincubation period completely disappeared within 12 hours, and the removal rates were higher than those in N-limited minimal medium. Isomers of hydroxylamino-dinitrotoluene were identified as the first detectable metabolites of TNT. These were transformed to amino-dinitrotoluenes, which also disappeared during further incubation from cultures of Irpex lacteus. During the initial phase of TNT degradation by I. lacteus, dinitrotoluenes were also detected after the transient formation of a hydride-Meisenheimer complex, indicating that I. lacteus used two different pathways of TNT degradation simultaneously.

Biodegradation, Environmental↗
PubMed2000

n-3 fatty acid deficiency decreases phosphatidylserine accumulation selectively in neuronal tissues.

We have previously shown that the docosahexaenoate (22:6n-3) status in membrane phospholipids influences the biosynthesis and accumulation of phosphatidylserine (PS) in brain microsomes and C6 glioma cells. In the present study, we investigated whether the observed effect of membrane docosahexaenoic acid status on PS accumulation is universal or occurs specifically in neuronal tissues. We observed that rat brain cortex, brain mitochondria, and olfactory bulb, where 22:6n-3 is highly concentrated, contain significantly higher levels of PS in comparison to liver and adrenal, where 22:6n-3 is a rather minor component. Phospholipid molecular species analysis revealed that in brain cortex, mitochondria, and olfactory bulb 18:0,22:6n-3 was the most abundant species representing 45-65% of total PS. In nonneuronal tissues such as liver and adrenal, 18:0,20:4n-6 was the major PS species. Dietary depletion of n-3 fatty acids during prenatal and postnatal developmental periods decreased the brain 22:6n-3 content by more than 80%, with a concomitant increase in 22:5n-6 in all tissues. Under these conditions, an approximately 30-35% reduction in total PS in rat brain cortex, brain mitochondria, and olfactory bulb was observed, while PS levels in liver and adrenal were unchanged. The observed reduction of PS content in neuronal membranes appears to be due to a dramatic reduction of 18:0,22:6n-3-PS without complete replacement by 18:0,22:5n-6-PS. These results establish that variations in membrane 22:6n-3 fatty acid composition have a profound influence on PS accumulation in neuronal tissues where 22:6n-3 is abundant. These data have implications in neuronal signaling events where PS is believed to play an important role.

Adrenal Glands↗
PubMed2000

Nitric oxide-mediated endothelium-dependent relaxation of rat thoracic aorta induced by aqueous extract of red rice fermented with Monascus ruber.

Vasodilatory effects of aqueous extract of red rice fermented with Monascus ruber IFO32318 were examined on the isolated rat aorta. The water phase of fermented rice with Monascus (WP/FRM, 0.1-10 mg/ml) caused a transient relaxation of the endothelium-intact rat aorta precontracted with norepinephrine (NE, 300 nM). The WP/FRM-induced relaxation was abolished by removal of endothelium or in the presence of N(G)-nitro-L-arginine (L-NNA, 10 microM), a nitric oxide (NO) synthase inhibitor. Neither atropine, a muscarinic receptor antagonist (10 microM), nor indomethacin, a cyclooxygenase inhibitor (10 microM), altered the WP/FRM-induced endothelium-dependent relaxation. gamma-Aminobutyric acid (GABA), one of the principle components of the extract, did not affect the muscle tension of the aorta with intact endothelium. In addition, WP/FRM increased the production of NO in primary cultured endothelial cells from human umbilical vein. The enhanced production of NO by WP/FRM was diminished by pretreatment with L-NNA (10 microM). In conclusion, WP/FRM induces relaxation of rat aorta by releasing NO from endothelium. There seem to be some unknown factor(s) other than acetylcholine (Ach) and GABA, in the aqueous extract of red rice, which stimulate vascular endothelial cells to produce and/or release NO leading to endothelium-dependent relaxation by WP/FRM.

Acetylcholine↗
PubMed2000

House dust mite-specific IgE antibodies in induced sputum are associated with sputum eosinophilia in mite-sensitive asthmatics.

BACKGROUND: Although allergen-specific IgE antibodies have been considered to play an important role in the pathogenesis of atopic asthma, the role of IgE antibodies in the development of airway inflammation is not well defined. OBJECTIVE: To evaluate the association between allergen-specific IgE antibodies and inflammation of the asthmatic airway. METHODS: We measured house dust mite (HDM; Dermatophagoides farinae)-specific IgE antibodies in both serum and induced sputum from 16 HDM-sensitive asthmatic patients, and evaluated their association with sputum eosinophilia and eosinophil cationic protein (ECP) levels in induced sputum. RESULTS: Levels of HDM-specific IgE antibodies in induced sputum were significantly higher in asthmatic patients than in controls (P < .01). In asthmatic patients, levels of HDM-specific IgE antibodies were significantly higher in induced sputum samples with eosinophilia (sputum eosinophil count > or = 5% of 200 counted non-squamous cells) than in those without eosinophilia (P < .05). There were no significant differences in serum levels of HDM-specific IgE antibodies between asthmatic patients with sputum eosinophilia and asthmatic patients without sputum eosinophilia. In asthmatic patients, sputum ECP levels were significantly correlated with levels of HDM-specific IgE antibodies (r = 0.60, P = .01) in induced sputum but not with those in serum. CONCLUSION: We conclude that allergen-specific IgE antibodies in induced sputum from atopic asthmatics are associated with sputum eosinophilia. This result suggests that IgE-dependent mechanisms are involved in eosinophilic inflammation of the airway in atopic asthmatics.

Allergens↗
PubMed2000

Two-spotted spider mite (Tetranychus urticae): an important allergen in asthmatic non-farmers symtomatic in summer and fall months.

BACKGROUND: The Tetranychus urticae (two-spotted spider mite, TSM) is a spider mite commonly found on fruit trees, herbaceous plants, and greenhouse flowers. OBJECTIVE: To evaluate the clinical significance of TSM-derived allergens in non-farmers with asthma living around pear orchards, and to assess the allergenic relationship with house dust mite. METHODS: Skin prick tests with TSM were performed in 50 asthmatic non-farmers living around pear orchards. The serum TSM-specific IgE was measured in the 16 asthmatics with a positive skin response to TSM. To diagnose TSM-induced asthma, specific bronchial challenges with TSM were performed in the 16 asthmatics. ELISA inhibition tests were performed to assess the allergenic cross-reactivity with house dust mites. RESULTS: Ten of the 16 asthmatics with positive skin responses to TSM showed a significant bronchoconstriction following inhalation of TSM. Eight of the ten TSM-induced asthmatics had high serum TSM-specific IgE and one showed a positive skin response only to TSM. Their asthmatic symptoms were aggravated seasonally, especially in summer and early fall. On ELISA inhibition tests, partial inhibitions with D. pteronyssinus antigens were noted in sera from five asthmatics with positive skin responses to both TSM and D. pteronyssinus, although no inhibition was noted in serum from an asthmatic with a positive skin response only to TSM. CONCLUSION: Tetranychus urticae may be an important allergen in asthmatic non-farmers living around pear orchards and TSM extracts contain species-specific allergens as well as commonly shared allergens with house dust mite.

Adolescent↗
PubMed2000

Sensitivity to citrus red mite and the development of asthma.

BACKGROUND AND OBJECTIVE: The citrus red mite (Panonychus citri, CRM) is an important allergen in the development of asthma and/or rhinitis in citrus farmers and a common sensitizing allergen among exposed children. The aim of this study was to evaluate CRM-induced skin responses and serum-specific IgE, IgG4, and IgG1 responses, and their role in the development of asthmatic symptoms among exposed adolescents. METHODS: A total of 100 adolescents between the ages of 15 and 16 years (59 males and 41 females) were randomly recruited. All of the subjects responded to the ISAAC questionnaire themselves. Skin prick tests to CRM were carried out and serum-specific IgE, IgG4, and IgG1 levels were measured using ELISA. RESULTS: Fourteen subjects (14%) had experienced wheezing during last 12 months. The wheal size formed by CRM was larger than 3 mm in 23 subjects (23%). Serum-specific IgE levels were elevated in 21 subjects (21%), IgG4 levels were elevated in 32 subjects (32%), and IgG1 levels were elevated in five subjects (5%). The prevalence of wheezing during last 12 months was significantly higher in subjects with positive skin responses and serum-specific IgE responses induced by CRM than in those with negative skin responses and low serum IgE responses (30.4% versus 9.0%, P < .05; 33.3% versus 8.7%, P < .05). The prevalence of wheezing, however, did not differ according to serum-specific IgG4 levels (9.4% versus 16.2%, P > .05). Skin responses to CRM showed a significant correlation with serum-specific IgE levels, but not with IgG1 and IgG4 levels. Serum CRM-specific IgE levels correlated with specific IgG1 and IgG4 levels, but no significant correlation was found between serum IgG1 and IgG4 levels. CONCLUSION: The specific IgE responses induced by CRM were prevalent among adolescents living near citrus farms, and may be important in the development of asthma. The specific IgG4 and IgG responses induced by CRM play a minimal role in the development of asthma symptoms.

Adolescent↗
PubMed2000

Studies of the mechanisms of adduction of 2'-deoxyadenosine with styrene oxide and polycyclic aromatic hydrocarbon dihydrodiol epoxides.

The mechanism of adduction of 2'-deoxyadenosine by styrene oxide and polycyclic aromatic hydrocarbon dihydrodiol epoxides has been explored using (15)N(6)-labeled adenine nucleosides. The extent of reaction at N1 versus N(6) was evaluated by (1)H NMR of the N(6) adducts after allowing Dimroth rearrangement to occur. Products arising from attack at N1 followed by Dimroth rearrangement exhibited a small two-bond (1)H-(15)N coupling constant (N1-H2 J approximately 13 Hz); products from direct attack exhibited a much larger one-bond (1)H-(15)N coupling constant (J approximately 90 Hz). In the case of styrene oxide, all of the N(6) beta adduct arose by initial attack at N1, whereas the majority (70-80%) of the N(6) alpha adducts came from direct attack. The styrene oxide reaction was also studied with a self-complementary oligodeoxynucleotide (24-mer) containing nine (15)N(6)-labeled adenine residues. NMR examination of the N(6) alpha- and beta-styrene oxide adducts isolated after enzymatic degradation of the 24-mer gave very similar results, indicating that N1 attack can occur readily even with a duplexed oligonucleotide. With the PAH dihydrodiol epoxides, only naphthalene dihydrodiol epoxide exhibited significant initial reaction at N1 (50%). No detectable rearranged product was seen in reactions with benzo[a]pyrene dihydrodiol epoxide or non-bay or bay region benz[a]anthracene dihydrodiol epoxide; interestingly, a small amount of N1 attack (5-7%) was seen in the case of benzo[c]phenanthrene dihydrodiol epoxide. It appears that initial attack at N1 is only a significant reaction pathway for epoxides attached to a single aromatic ring.

Base Sequence↗
PubMed2000

Analysis of essential leucine residue for catalytic activity of novel thermostable chitosanase by site-directed mutagenesis.

Bacterial chitosanases share weak amino acid sequence similarities at certain regions of each enzyme. These regions have been assumed to be important for catalytic activities of the enzyme. To verify this assumption, the functional importance of the conserved region in a novel thermostable chitosanase (TCH-2) from Bacillus coagulans CK108 was investigated. Each of the conserved amino acid residues (Leu64, Glu80, Glu94, Asp98, and Gly108) was changed to aspartate and glutamine or asparagine and glutamate by site-directed mutagenesis, respectively. Kinetic parameters for colloidal chitosan hydrolysis were determined with wild-type and 10 mutant chitosanases. The Leu64 --> Arg and Leu64 --> Gln mutations were essentially inactive and kinetic parameters such as Vmax and kcat were approximately 1/10(7) of those of the wild-type enzyme. The Asp98 --> Asn mutation did not affect the Km value significantly, but decreased kcat to 15% of that of wild-type chitosanase. On the other hand, the Asp98 --> Glu mutation affected neither Km nor kcat. The observation that approximately 15% of activity remained after the substitution of Asp98 by Asn indicated that the carboxyl side chain of Asp98 is not absolutely required for catalytic activity. These results indicate that the Leu64 residue is directly involved in the catalytic activity of TCH-2.

Amino Acid Sequence↗
PubMed2000

The role of IL-12 in inflammatory activity of patients with rheumatoid arthritis (RA).

The aim of this study was to investigate the role of IL-12 in patients with RA. IL-12 (p70) and its associated cytokines were measured in sera and synovial fluid (SF) using an enzyme-linked immunosorbent method. Seven American College of Rheumatology (ACR) core set measures as well as IL-12 levels were sequentially monitored at the commencement and 4 months after treatment with a low-dose steroid and disease-modifying anti-rheumatic drugs (DMARDs). In sera, 64 (42.2%) of 152 RA patients had detectable concentrations of IL-12 (p70), whereas one (1.4%) of 69 osteoarthritis (OA) patients and five (10%) of 50 healthy controls had detectable IL-12 (P < 0.001). The median level of circulating IL-12 was also higher in RA patients (P < 0.001). In SF, the number of patients with detectable IL-12 and the median IL-12 levels were significantly higher in RA patients (n = 53) than in OA patients (n = 22). In paired samples (n = 53) of sera and SF from RA patients, IL-12 levels were higher in the SF than in sera (P < 0.001). Patients with detectable IL-12 (n = 51) in sera had higher tender joint scores (P = 0.003), swollen joint scores (P < 0.001) and C-reactive protein (CRP; P = 0.036), than those without (n = 55). Four months after treatment with DMARDs, the improved group showed a larger IL-12 decrease than the non-improved group (P = 0.017). The levels of IL-12 correlated positively with those of IL-2, interferon-gamma, IL-6, and tumour necrosis factor-alpha, but were correlated inversely with those of IL-10. Our results demonstrate that IL-12 levels reflect RA disease activity and that IL-12 is involved in the production of proinflammatory cytokines. An IL-12 blockade could be useful for the treatment of RA.

Adult↗
PubMed2000

Incidence and prevalence of ulcerative colitis in the Songpa-Kangdong District, Seoul, Korea, 1986-1997.

BACKGROUND AND AIMS: Ulcerative colitis (UC) is regarded as a rare disease in developing countries, but accurate data are generally lacking. We performed the present study to evaluate the incidence and prevalence of UC in Korea. METHODS: A retrospective study was performed from 1986 to 1997 in the Songpa-Kangdong district of Seoul, Korea. To recruit UC patients as completely as possible, multiple information sources including all medical facilities in the study area and three referral centres located nearby, but outside the study area were used. The incidence and prevalence rates were adjusted using the 1997 Korean population statistics. RESULTS: During the study period, a total of 94 incident cases were identified, for an adjusted mean annual incidence rate of 0.68 per 100,000 inhabitants. On 31 December 1997, 91 patients with UC lived in the study area, giving an adjusted prevalence rate of 7.57 per 100,000 inhabitants. By using the Poisson regression analysis, the annual incidence rate increased significantly from 0.20 per 100,000 inhabitants in 1986-1988 to 1.23 per 100,000 inhabitants in 1995-1997 (P < 0.005). Patient age at diagnosis, the interval from onset of symptoms to diagnosis, and the disease extent at diagnosis were fairly constant throughout the study period. CONCLUSIONS: The incidence and prevalence of UC in our study area are still low compared with those of Western countries, but the incidence rate is steadily increasing.

Adult↗
PubMed2000

Transthoracic echocardiographic demonstration of massive pulmonary thrombus caused by protein C deficiency.

Few cases of pulmonary embolism detected by transthoracic echocardiography (TTE) have been reported. We present a case of a patient affected by pulmonary embolism caused by protein C deficiency. Transthoracic echocardiography showed a thrombus in transit (ie, visualization of a thrombus within the pulmonary artery). A hypercoagulable state caused by deficiency of protein C is a rare cause of pulmonary thromboembolism. Our experience demonstrates a massive pulmonary thrombus resulting from such a deficiency. Transthoracic echocardiography should be considered as the first diagnostic method for patients with suspected pulmonary embolism.

Adult↗
PubMed2000

A case of primary hepatic lymphoma with hepatitis C liver cirrhosis.

Primary hepatic lymphoma is rare. The usual type is a large-cell, high-grade malignant B-cell lymphoma, although T-cell types have been described. Several cases of primary hepatic lymphoma of B-cell origin developing in patients with chronic hepatitis C virus infection have been reported. Recently, new findings have raised the question of the induction of lymphoma by hepatitis C virus. However, the causal relationship between hepatitis C viral infection and primary hepatic lymphoma remains obscure. This article reports a case of histologically proven primary hepatic lymphoma of T-cell origin, which was confined to the liver, in the setting of hepatitis C liver cirrhosis. This association has not previously been reported.

Aged↗
PubMed2000

Thermostable chitosanase from Bacillus sp. Strain CK4: cloning and expression of the gene and characterization of the enzyme.

A thermostable chitosanase gene from the environmental isolate Bacillus sp. strain CK4, which was identified on the basis of phylogenetic analysis of the 16S rRNA gene sequence and phenotypic analysis, was cloned, and its complete DNA sequence was determined. The thermostable chitosanase gene was composed of an 822-bp open reading frame which encodes a protein of 242 amino acids and a signal peptide corresponding to a 30-kDa enzyme. The deduced amino acid sequence of the chitosanase from Bacillus sp. strain CK4 exhibits 76.6, 15.3, and 14.2% similarities to those from Bacillus subtilis, Bacillus ehemensis, and Bacillus circulans, respectively. C-terminal homology analysis shows that Bacillus sp. strain CK4 belongs to cluster III with B. subtilis. The gene was similar in size to that of the mesophile B. subtilis but showed a higher preference for codons ending in G or C. The enzyme contains 2 additional cysteine residues at positions 49 and 211. The recombinant chitosanase has been purified to homogeneity by using only two steps with column chromatography. The half-life of the enzyme was 90 min at 80 degrees C, which indicates its usefulness for industrial applications. The enzyme had a useful reactivity and a high specific activity for producing functional oligosaccharides as well, with trimers through hexamers as the major products.

Amino Acid Sequence↗
PubMed2000

Intracellular infection by the human granulocytic ehrlichiosis agent inhibits human neutrophil apoptosis.

In patients with human granulocytic ehrlichiosis (HGE), the HGE agent has been seen only in the peripheral blood granulocytes, which have a life span too short for ehrlichial proliferation. To determine if the HGE agent delays the apoptosis of human peripheral blood neutrophils for its advantage, peripheral blood granulocytes consisting mostly of neutrophils were incubated with freshly freed host cell-free HGE agent in vitro. The HGE agent induced a significant delay in morphological apoptosis and the cytoplasmic appearance of histone-associated DNA fragments in the granulocytes. This antiapoptotic effect was dose dependent. Although much weaker than the HGE agent freshly freed from the host cells, noninfectious purified HGE agent stored frozen and thawed also had antiapoptotic effect, which was lost with proteinase K treatment but not with periodate treatment. Treatment of neutrophils with a transglutaminase inhibitor, monodansylcadaverine, blocked the antiapoptotic effect of the HGE agent. Addition of oxytetracycline, however, did not prevent or reverse the antiapoptotic effect of the HGE agent. These results suggest that binding of a protein component(s) of the HGE agent to neutrophils and subsequent cross-linking and/or internalization of the receptor and ehrlichiae are required for antiapoptotic signaling, but ehrlichial protein synthesis and/or proliferation is not required. MG-132, a proteasome inhibitor, and cycloheximide accelerated the apoptosis of neutrophils and overrode the antiapoptotic effect of the HGE agent. Studies with specific inhibitors suggest that protein kinase A, NF-kappaB, and interleukin 1beta are not involved in the antiapoptotic mechanism of the HGE agent.

Apoptosis↗