Biomedical subjects

Y H Kim

Publications and source records attributed to Y H Kim.

At least 145 records · Page 8Linked to original sources

PubMed2001

A comparative trial of two retinoids commonly used in the treatment of acne vulgaris.

BACKGROUND: Topical retinoids are highly effective treatments for acne vulgaris. The various formulations and concentrations available allow physicians to tailor therapies to individual patient's needs and minimize the cutaneous irritation that is often observed with the use of these drugs. OBJECTIVE: To compare the efficacy and safety of tretinoin gel microsphere 0.1% with adapalene gel 0.1% in the treatment of acne vulgaris. METHODS: A 12-week double-blind study was conducted, and patients were evaluated at baseline and at weeks 2, 3, 4, 6, 8, 10, and 12. RESULTS: Although the two drugs displayed similar efficacy in the resolution of acne lesions at 12 weeks, a significantly greater reduction in the number of comedones was seen at week 4 among patients treated with tretinoin gel microsphere (p = 0.047). Patients receiving tretinoin gel microsphere had an increased incidence of dryness (weeks 8 and 10) and peeling (weeks 3, 6, 8, and 10) compared with those patients treated with adapalene gel, but the two groups were comparable with respect to erythema, burning/stinging, and itching. CONCLUSION: Both drugs have similar efficacy in the resolution of acne lesions but tretinoin gel microsphere may result in a faster onset of action in the reduction of comedones compared to adapalene.

Acne Vulgaris↗

PubMed2001

Domain and genomic sequence analysis of bdellin-KL, a leech-derived trypsin-plasmin inhibitor.

Bdellin-KL is a trypsin-plasmin inhibitor from Hirudo nipponia, whose N-terminal sequence was identified as a non-classical Kazal-type. A cDNA clone encoding the inhibitor was isolated by reverse transcription-PCR and 5' rapid amplification of cDNA ends. The cDNA showed an open reading frame of 155 amino acids comprising one signal peptide and two separated domains. The C-terminal domain consists of distinct internal repeats, including HHEE and HHDD. The bdellin-KL sequence, from the constructed genomic library of Korean leech, was determined for the 2109 bases comprising the open reading frame and flanking regions (3' and 5'). The promoter region contains potential regulatory sequence motifs, including TATA, CAAT, and GC boxes. To characterize the properties of each domain, an N-terminal fragment was prepared by limited proteolysis of the intact protein. The inhibitory activity of the region was as potent as that of the intact protein. This suggests that the compact domain plays an important part in the inhibitory action of bdellin-KL. The C-terminal domain was revealed to have binding affinity to ions such as Ca(2+), Zn(2+), Fe(3+), and Fe(2+) without an influence on the inhibitory activity. This study demonstrates that bdellin-KL may be a novel bifunctional protein with two distinct domains.

Animals↗

PubMed2001

Comparing the effect on protein stability of methionine oxidation versus mutagenesis: steps toward engineering oxidative resistance in proteins.

The biological activity of some proteins is known to be sensitive to oxidative damage caused by a variety of oxidants. The model protein staphylococcal nuclease was used to explore the effect on protein structural stability of oxidizing methionine to the sulfoxide form. These effects were compared with the effects of substituting methionines with isoleucine and leucine, a potential strategy for stabilizing proteins against oxidative damage. Wild-type nuclease and various mutants were oxidized with hydrogen peroxide. Stabilities of both oxidized and unoxidized proteins were determined by guanidine hydrochloride denaturation. Oxidation destabilized the wild-type protein by over 4 kcal/mol. This large loss of stability supports the idea that in some cases loss of biological activity is linked to disruption of the protein native state. Comparison of mutant protein's stability losses upon oxidation showed that methionines 65 and 98 had a much greater destabilizing effect when oxidized than methionines 26 or 32. While substitution of methionine 98 carried as great an energetic penalty as oxidation, substitution at position 65 was less disruptive than oxidation. Thus a simple substitution mutagenesis strategy to protect a protein against oxidative destabilization is practical for some methionine residues.

Enzyme Stability↗

PubMed2001

Comparison of fixed-bearing and mobile-bearing total knee arthroplasties.

The purpose of the current study was to directly compare the results of fixed-bearing and mobile-bearing total knee arthroplasties in the same patient who had bilateral simultaneous total knee replacements. A fixed-bearing total knee prosthesis (AMK) was implanted in one knee and a mobile-bearing total knee prosthesis (LCS) was implanted in the other knee in 116 patients. The average age of the patients was 65 years (range, 33-70 years). The average followup was 7.4 years (range, 6-8 years). Clinical and radiographic followup was done using Knee Society and Hospital for Special Surgery knee rating systems at 6 weeks, 3 months, 6 months, 1 year after surgery, and yearly thereafter. Total knee score, pain score, mean functional score, and range of motion were comparable in both groups. Two knee replacements (2%) in one patient with AMK prostheses were revised because of complete wear of tibial bearing polyethylene. One knee replacement (1%) in one patient with an LCS prosthesis was revised because of dislocation of the medial tibial bearing polyethylene and one knee replacement (1%) in one patient with an LCS prosthesis was revised because of complete wear of the medial tibial bearing polyethylene. No knee had aseptic loosening or osteolysis in either group. After a minimum followup of 6 years, the results of fixed- and mobile-bearing total knee prostheses in the current series are favorable. However, there is no evidence to prove the superiority of the mobile-bearing total knee design.

Adult↗

PubMed2001

The effect of sildenafil on lower esophageal sphincter and body motility in normal male adults.

OBJECTIVE: Sildenafil relaxes smooth muscle by blocking type 5 phosphodiesterase, which destroys nitric oxide-stimulated cyclic guanosine monophosphate. The aim of this study is to investigate the change of lower esophageal sphincter (LES) and body motility with the lapse of time after sildenafil infusion in normal male adults. METHODS: After basal esophageal manometry in eight healthy male adult volunteers, we infused a 50-mg tablet of sildenafil dissolved in water in the stomach through the manometry catheter and observed the changes of LES and body motility with the lapse of time. We randomized the study population into two groups, and esophageal manometry was repeated in LES and body sequence in four volunteers and in body and LES sequence in the other four volunteers immediately after sildenafil infusion. RESULTS: LES resting pressure significantly decreased after sildenafil infusion. The body peristaltic amplitude gradually decreased and eventually disappeared, and the latency increased significantly after sildenafil infusion in both the proximal and distal esophagus. CONCLUSIONS: These data support that nitric oxide mediates LES relaxation and the timing of esophageal peristalsis. In the future, sildenafil can be tried in some esophageal motor disorders, which have defects in nitric oxide neuromuscular communication.

Adult↗

PubMed2001

Visualization of multiple incoherent sources by the backward prediction of near-field acoustic holography.

When there are multiple noise sources which share the same frequency bands, a sound field measured or estimated by near-field acoustic holography (NAH) is obviously the combination of the sound fields generated by the multiple sources. The objective of this paper is to estimate the sound field generated by each source when the coherence functions between sources are zeros. This objective can be achieved by obtaining signals coherent to sources. This paper proposes a method to obtain the coherent signals by using the spatial information of NAH. The proposed method obtains the coherent signals from pressure signals at source positions estimated by the backward prediction of NAH. Thus it does not require any prior information on source positions, unlike the conventional method, which placed sensors close to sources in order to obtain the coherent signals. The proposed method was verified by a numerical simulation using two incoherent monopole sources.

Journal Article↗

PubMed2001

Visualization of pass-by noise by means of moving frame acoustic holography.

The noise generated by pass-by test (ISO 362) was visualized. The moving frame acoustic holography was improved to visualize the pass-by noise and predict its level. The proposed method allowed us to visualize tire and engine noise generated by pass-by test based on the following assumption; the noise can be assumed to be quasistationary. This is first because the speed change during the period of our interest is negligible and second because the frequency change of the noise is also negligible. The proposed method was verified by a controlled loud speaker experiment. Effects of running condition, e.g., accelerating according to ISO 362, cruising at constant speed, and coasting down, on the radiated noise were also visualized. The visualized results show where the tire noise is generated and how it propagates.

Journal Article↗

PubMed2001

Identification of deoxynivalenol- and nivalenol-producing chemotypes of Gibberella zeae by using PCR.

Gibberella zeae, a major cause of cereal scab, may be divided into two chemotypes based on production of the trichothecenes deoxynivalenol (DON) and nivalenol (NIV). We cloned and sequenced the gene cluster for trichothecene biosynthesis from each chemotype. G. zeae H-11 is a DON producer isolated from corn, and G. zeae 88-1 is a NIV producer from barley. We sequenced a 23-kb gene cluster from H-11 and a 26-kb cluster from 88-1, along with the unlinked Tri101 genes. Each gene cluster contained 10 Tri gene homologues in the same order and transcriptional directions as those of Fusarium sporotrichioides. Between H-11 and 88-1 all of the Tri homologues except Tri7 were conserved, with identities ranging from 88 to 98% and 82 to 99% at the nucleotide and amino acid levels, respectively. The Tri7 sequences were only 80% identical at the nucleotide level. We aligned the Tri7 genes and found that the Tri7 open reading frame of H-11 carried several mutations and an insertion containing 10 copies of an 11-bp tandem repeat. The Tri7 gene from 88-1 carried neither the repeat nor the mutations. We assayed 100 G. zeae isolates of both chemotypes by PCR amplification with a primer pair derived from the Tri7 gene and could differentiate the chemotypes by polyacrylamide gel electrophoresis. The PCR-based method developed in this study should provide a simple and reliable diagnostic tool for differentiating the two chemotypes of G. zeae.

Cloning, Molecular↗

PubMed2001

Determinants of Staphylococcus aureus nasal carriage.

Nasal carriage of Staphylococcus aureus has been identified as a risk factor for community-acquired and nosocomial infections. We screened 230 donors of diverse ethnic and socioeconomic backgrounds and identified 62 (27%) whose nasal secretions were colonized by S. aureus. In 18 donors in whom the various regions of the nasal luminal surface were separately sampled, the predominant region of S. aureus colonization was the moist squamous epithelium on the septum adjacent to the nasal ostium. Nasal fluid from carriers was defective in killing endogenous S. aureus and nasal carrier isolates of S. aureus but not a laboratory S. aureus strain. Transmission electron microscopy revealed that S. aureus isolates incubated in nasal fluid from carriers for 2 h at 37 degrees C were less damaged than those incubated in noncarrier fluid and were coated with an electron-dense layer. Compared with that from healthy donors and patients with acute rhinitis, nasal fluid from carriers contained elevated concentrations of the neutrophil-derived defensins human neutrophil peptides 1 to 3 (47- and 4-fold increases, respectively), indicative of a neutrophil-mediated inflammatory host response to S. aureus colonization. The concentration of the inducible epithelial antimicrobial peptide human beta-defensin 2 was also highly elevated compared to that in healthy donors, in whom the level was below the detection limit, or patients with acute rhinitis (sixfold increase). Thus, nasal carriage of S. aureus takes hold in nasal fluid that is permissive for colonization and induces a local inflammatory response that fails to clear the colonizing bacteria.

Body Fluids↗

PubMed2001

Peripheral T-cell lymphoma of the colon: double-contrast barium enema examination findings in six patients.

PURPOSE: To evaluate radiologic findings of peripheral T-cell lymphoma (PTCL) of the colon at double-contrast barium enema examination. MATERIALS AND METHODS: Double-contrast barium enema findings in six patients with pathologically proved PTCL of the colon were retrospectively evaluated and compared with colonoscopic and histopathologic findings. RESULTS: There was a diffuse involvement of almost all segments of the colon in four patients and a focal segmental involvement in two. Frequent findings at double-contrast barium enema examination included geographic ulcerations (n = 6), aphthous ulcerations (n = 4), pseudopolyps (n = 4), circumferential luminal narrowing (n = 4), and ileocecal deformity (n = 4). CONCLUSION: PTCL of the colon manifested as either a diffuse or a focal segmental lesion and showed extensive mucosal ulceration at double-contrast barium enema examination. These findings are similar to those of inflammatory bowel disease and are different from those of colorectal lymphoma with the B-cell phenotype.

Adult↗

PubMed2001

Fibroblast culture on surface-modified poly(glycolide-co-epsilon-caprolactone) scaffold for soft tissue regeneration.

Novel porous matrices made of a copolymer of glycolide (G) and epsilon-caprolactone (CL) (51 : 49, Mw 103000) was prepared for tissue engineering using a solvent-casting particulate leaching method. Poly(glycolide-co-epsilon-caprolactone) (PGCL) copolymer showed a rubber-like elastic characteristic, in addition to an amorphous property and fast biodegradability. In order to investigate the effect on the fibroblast culture, PGCL scaffolds of varying porosity and pore size, in addition to surface-hydrolysis or collagen coating, were studied. The large pore-sized scaffold (pore size >150 microm) demonstrated a much greater cell adhesion and proliferation than the small pore-sized one. In addition, the higher porosity, the better the cell adhesion and proliferation. The surface-hydrolyzed PGCL scaffold showed enhanced cell adhesion and proliferation compared with the unmodified one. Type I collagen coating revealed a more pronounced contribution for increased cell interactions than the surface-hydrolyzed one. These results demonstrate that surface-modified PGCL scaffold can provide a suitable substrate for fibroblast culture, especially in the case of soft tissue regenerations.

3T3 Cells↗

PubMed2001

Critical role of central facilitation in the glottic closure reflex.

The sphincteric function of the larynx, essential to lower airway protection, is most efficiently achieved through strong reflex adduction by both vocal cords. We hypothesize that central facilitation is an essential component of a bilateral adductor reflex and that its disturbance could result in weakened sphincteric closure. Six adult 50-kg pigs underwent evoked response laryngeal electromyography under 0.5 to 1.0 minimal alveolar concentration (MAC) isoflurane anesthesia. The internal branch of the superior laryngeal nerve was stimulated through bipolar platinum-iridium electrodes, and recording electrodes were positioned in the ipsilateral and contralateral thyroarytenoid muscles. Consistent threshold responses were obtained ipsilaterally from 0.5 to 1.0 MAC anesthesia. However, the contralateral reflex responses approached 0% in successive trials as anesthetic levels approached 1.0 MAC. Alteration of central facilitation by deepening anesthesia abolishes the crossed adductor reflex, predisposing to a weakened glottic closure response. A precise understanding of this effect may improve the prevention of aspiration in patients emerging from prolonged sedation or under heavy psychotropic control.

Anesthesia↗

PubMed2001

Age dependence of laryngeal chemoreflex in puppies.

Previously collected data have indicated that the laryngeal chemoreflex (LCR) response is exaggerated during a critical period of postnatal development in several experimental animals. These animals had fewer anatomic and physiological similarities to humans than do puppies. This investigation of the LCR in 14 anesthetized puppies was undertaken to determine age-related differences in the response to stimulation of the supraglottic laryngeal mucosa by saline solution, distilled water, cow's milk, and acid at pH 1.0. The dogs were divided into 3 age groups: group 1 consisted of 4 dogs that were 2 weeks old, and in groups 2 and 3 there were 5 puppies each, of 4 and 6 weeks of age, respectively. The LCR response (laryngospasm, apnea, respiratory depression, and bradycardia) was found in the puppies only after stimulation of the laryngeal mucosa with acid at pH 1.0, and it was more easily achieved in the 4- and 6-week age groups than in the 2-week group. These findings suggest that the LCR is an age-dependent response that appears in dogs only after 2 weeks of age. The important implication of this finding is that postnatal neural maturation may influence the laryngeal reflex in humans to some extent.

Age Factors↗

PubMed2001

Inhibitory effects of ethaverine, a homologue of papaverine, on monoamine oxidase activity in mouse brain.

The effects of benzylisoquinoline compounds such as ethaverine, laudanosine, and tetrahydropapaverine on monoamine oxidase (MAO, EC 1.4.3.4) activity in mouse brain were investigated. Ethaverine showed an inhibition of MAO activity in a concentration-dependent manner (57.6% inhibition at 40 microm). Papaverine also inhibited MAO activity (38.1% inhibition at 40 microM). However, laudanosine and tetrahydropapaverine did not inhibit MAO activity. The IC50 value of ethaverine for MAO was 25.5 microm. Ethaverine non-competitively inhibited MAO activity with a substrate kynuramine. The Ki value for ethaverine was 11.9 microM. In addition, ethaverine proved to preferentially inhibit type B MAO activity in a concentration-dependent manner, with an IC50 value of 32.8 microm. These results suggest that ethaverine partially contributes to the regulation of catecholamine content.

Animals↗

PubMed2001

Cytotoxic alkaloids and a flavan from the bulbs of Crinum asiaticum var. japonicum.

A new pyrrolophenanthridone alkaloid, criasiaticidine A (1), was isolated from the bulbs of Crinum asiaticum var. japonicum, together with pratorimine (2), lycorine (3) and 4'-hydroxy-7-methoxyflavan (4). The structure of the new alkaloid was determined to be 4,5-etheno-9,10-dihydroxy-6-phenanthridone by spectroscopic means. The cytotoxicity of the isolated compounds 1-4 was evaluated in vitro against Meth-A (mouse sarcoma) and Lewis lung carcinoma (mouse lung carcinoma) tumor cell lines. Furthermore, 3 was examined for in vivo antitumor activity with LLC tumor cells.

Alkaloids↗

PubMed2001

Huge calcified aneurysm of the sinus of Valsalva.

Aneurysms of the sinus of Valsalva often remain undiagnosed until they rupture. A 61-year-old man had a huge, heavily calcified unruptured aneurysm, originating from the right sinus of Valsalva, detected incidentally on a chest radiograph taken for the diagnosis of cardiomegaly. Two-dimensional echocardiography revealed pericardial effusion with a huge calcified mass compressing the right ventricular outflow tract. The Doppler color-flow echocardiogram showed blood flow from the aortic root into the aneurysm. A chest computed tomographic scan revealed a large thrombosed aneurysm originating from the aortic root and measuring 10x10 cm. After pericardiocentesis, cardiac catheterization was performed, which showed that the right ventricular systolic pressure had elevated to 80 mmHg. Aortic root aortography demonstrated a huge unruptured calcified aneurysm in the sinus of Valsalva arising from the right coronary sinus. The patient underwent surgical correction to prevent aneurysmal rupture and to relieve the right ventricular outflow obstruction.

Aortic Aneurysm↗

PubMed2001

Enzymatic synthesis of two ginsenoside Re-beta-xylosides.

Two new beta-xylosyl derivatives of ginsenoside Re, 20(S)-protopanaxatriol 6-O-alpha-L-rhamnopyranosyl-(1 --> 2)-[beta-D-xylopyranosyl-(1 --> 4)]-beta-D-glucopyranosyl-20-O-beta-D-glucopyranoside and 20(S)-protopanaxatriol 6-O-alpha-L-rhamnopyranosyl-(1 --> 2)-[beta-D-xylopyranosyl-(1 --> 6)]-beta-D-glucopyranosyl-20-O-beta-D-glucopyranoside, were respectively synthesized from p-nitrophenyl beta-D-xylopyranoside and phenyl beta-D-xylopyranoside as donors and ginsenoside Re as the acceptor in 25% acetone and acetonitrile by a cellulase preparation from Trichoderma viride and a beta-galactosidase preparation from Aspergillus oryzae. The latter enzyme preparation also catalyzed the hydrolysis of ginsenoside Re to the minor saponin, ginsenoside Rg2.

Aspergillus oryzae↗

PubMed2001

Transglycosylation to ginseng saponins by cyclomaltodextrin glucanotransferases.

Ten new alpha-glucosylginsenosides were found to be synthesized from dextrin and four ginsenosides, -Rb1, -Rc, -Re, and -Rg1, by the successive actions of B. stearothermophilus cyclomaltodextrin glucanotransferase and Rhizopus glucoamylase. Seven of them were isolated in the pure state by extraction with n-butanol saturated with water, silica gel column chromatography, and high pressure liquid chromatography, and identified as 3-O-[alpha-D-glcp-(1-->4)-beta-D-glcp-(1-->2)-beta-D-glcp]-20-O-[beta-D-glcp-(1-->6)-beta-D-glcp]-20(S)-protopanaxadiol, 3-O-[beta-D-glcp-(1-->2)-beta-D-glcp]-20-O-[alpha-D-glcp-(1-->4)-beta-D-glcp-(1-->6)-beta-D-glcp]-20(S)-protopanaxadiol, 3-O-[alpha-D-glcp-(1-->4)-beta-D-glcp-(1-->2)-beta-D-glcp]-20-O-[alpha-L-araf-(1-->6)-beta-D-glcp]-20(S)-protopanaxadiol, 3-O-[beta-D-glcp-(1-->2)-beta-D-glcp]-20-O-[(4G-alpha-D-glcp)-alpha-L-araf-(1-->6)-beta-D-glcp]-20(S)-protopanaxadiol, 6-O-[alpha-L-rhap-(1-->2)-beta-D-glcp]-20-O-[alpha-D-glcp-(1-->4)-beta-D-glcp]-20(S)-protopanaxatriol, 6-O-[alpha-D-glcp-(1-->4)-beta-D-glcp]-20-O-(beta-D-glcp)-20(S)-protopanaxatriol, and 6-O-[alpha-D-glcp-(1-->3)-beta-D-glcp]-20-O-(beta-D-glcp)-20(S)-protopanaxatriol, by spectroscopy (FAB-MS, IR, 1H-NMR and 13C-NMR) and hydrolysis products in 50% acetic acid. The bitterness of these alpha-glucosyl-ginsenosides was less than that of ginsenosides.

Chromatography, High Pressure Liquid↗