Search PubMed⌕ Search

Biomedical subjects

C Kim

Publications and source records attributed to C Kim.

At least 19 recordsLinked to original sources
PubMed2006

Alfentanil attenuates phenylephrine-induced contraction in rat aorta.

BACKGROUND AND OBJECTIVES: Alfentanil was reported to relax the rat aorta by direct action on the vascular smooth muscle. The aims of this in vitro study were to examine the effect of alfentanil on phenylephrine-induced contractions in the rat aorta and to determine the cellular mechanism associated with this process. METHODS: Endothelium-denuded aortic rings were suspended in order to record isometric tension. In the rings with or without 10(-6) mol naloxone or 10(-5) mol verapamil, the concentration-response curves for phenylephrine and potassium chloride were generated in the presence or absence of alfentanil (10(-6), 5 x 10(-5), 10(-4) mol). In the rings exposed to a calcium-free isotonic depolarizing solution, the contractile response induced by the addition of calcium was assessed in the presence or absence of alfentanil (5 x 10(-5), 10(-4) mol). RESULTS: Alfentanil (5 x 10(-5), 10(-4) mol) attenuated (P < 0.05) the phenylephrine-induced contraction in the ring with or without 10(-6) mol naloxone but had no effect on the phenylephrine-induced contraction in the rings pretreated with verapamil. Alfentanil (5 x 10(-5), 10(-4) mol) produced a significant rightward shift (P < 0.01) in the potassium chloride dose-response curve, and attenuated the contractile response (P < 0.001) induced by calcium in the calcium-free isotonic depolarizing solution in a dose-dependent manner. CONCLUSIONS: A supraclinical dose of alfentanil attenuates the phenylephrine-induced contraction via an inhibitory effect on calcium influx by blocking the l-type calcium channels in the rat aortic vascular smooth muscle.

Alfentanil↗
PubMed2006

Missing xy-band Fermi surface in 4d transition-metal oxide Sr2RhO4: effect of the octahedra rotation on the electronic structure.

Electronic structures of the 4d transition-metal oxide compound Sr2RhO4 are investigated by angle-resolved photoemission spectroscopy and density-functional electronic structure calculations. In the measured Fermi surfaces (FS) of Sr2RhO4, the xy-band FS sheet expected from the well-established results of the FS of Sr2RuO4 is missing, the volume of which should be different only by one additional electron for Sr2RhO4. The apparent contradiction is resolved by a careful analysis of the band structure where the rotation of octahedra results in the hybridization of e(g) and t(2g) states and thus plays a key role in the determination of the electronic structure near EF. The modification of the FS structure due to the distorted lattice is related to the charge transfer among the orbital states and suggested to be relevant to the metal-insulator transition in Ca(2-x)Sr(x)RuO4.

Journal Article↗
PubMed2006

Impaired long-term memory and long-term potentiation in N-type Ca2+ channel-deficient mice.

Voltage-dependent N-type Ca(2+) channels, along with the P/Q-type, have a crucial role in controlling the release of neurotransmitters or neuromodulators at presynaptic terminals. However, their role in hippocampus-dependent learning and memory has never been examined. Here, we investigated hippocampus-dependent learning and memory and synaptic plasticity at hippocampal CA3-CA1 synapses in mice deficient for the alpha(1B) subunit of N-type Ca(2+) channels. The mutant mice exhibited impaired learning and memory in the Morris water maze and the social transmission of food preference tasks. In particular, long-term memory was impaired in the mutant mice. Interestingly, among activity-dependent long-lasting synaptic changes, theta burst- or 200-Hz-stimulation-induced long-term potentiation (LTP) was decreased in the mutant, compared with the wild-type mice. This type of LTP is known to require brain-derived neurotrophic factor (BDNF). It was found that both BDNF-induced potentiation of field excitatory postsynaptic potentials and facilitation of the frequency of miniature excitatory postsynaptic currents (mEPSCs) were reduced in the mutant. Taken together, these results demonstrate that N-type Ca(2+) channels are required for hippocampus-dependent learning and memory, and certain forms of LTP.

Analysis of Variance↗
PubMed2006

A tyrosine hydroxylase-yellow fluorescent protein knock-in reporter system labeling dopaminergic neurons reveals potential regulatory role for the first intron of the rodent tyrosine hydroxylase gene.

Degeneration of the dopaminergic neurons of the substantia nigra is a hallmark of Parkinson's disease. To facilitate the study of the differentiation and maintenance of this population of dopaminergic neurons both in vivo and in vitro, we generated a knock-in reporter line in which the yellow fluorescent protein (YFP) replaced the first exon and the first intron of the tyrosine hydroxylase (TH) gene in one allele by homologous recombination. Expression of YFP under the direct control of the entire endogenous 5' upstream region of the TH gene was predicted to closely match expression of TH from the wild type allele, thus marking functional dopaminergic neurons. We found that YFP was expressed in dopaminergic neurons differentiated in vitro from the knock-in mouse embryonic stem cell line and in dopaminergic brain regions in knock-in mice. Surprisingly, however, YFP expression did not overlap completely with TH expression, and the degree of overlap varied in different TH-expressing brain regions. Thus, the reporter gene did not identify functional TH-expressing cells with complete accuracy. A DNaseI hypersensitivity assay revealed a cluster of hypersensitivity sites in the first intron of the TH gene, which was deleted by insertion of the reporter gene, suggesting that this region may contain cis-acting regulatory sequences. Our results suggest that the first intron of the rodent TH gene may be important for accurate expression of TH.

Animals↗
PubMed2006

Drosophila homolog of APP-BP1 (dAPP-BP1) interacts antagonistically with APPL during Drosophila development.

beta-Amyloid precursor protein binding protein 1 (APP-BP1) was previously identified based on its binding to the carboxyl terminal of beta-amyloid precursor protein. In this report, we have discovered that a mutation of dAPP-BP1 (Drosophila ortholog of APP-BP1) hinders tissue development, causes apoptosis in imaginal disc cells, and blocks the NEDD8 conjugation pathway. We show that dAPP-BP1 specifically binds the intracellular domain of APP-like protein (APPL). The dAPP-BP1 mutation partially suppresses the abnormal macrochaete phenotype of Appl(d), while overexpression of dAPP-BP1 causes abnormal macrochaetes. When APPL is overexpressed, the normal bristle pattern in the fly thorax is disturbed and apoptosis is induced in wing imaginal discs. APPL overexpression phenotypes are enhanced by reducing the level of dAPP-BP1. APPL overexpression is shown to inhibit the NEDD8 conjugation pathway. APPL-induced apoptosis is rescued by overexpression of dAPP-BP1. Our data suggest that APPL and dAPP-BP1 interact antagonistically during Drosophila development.

Amino Acid Sequence↗
PubMed2006

Influence of quantum size effects on island coarsening.

Surface x-ray scattering and scanning-tunneling microscopy experiments reveal novel coarsening behavior of Pb nanocrystals grown on Si(111)-(7 x 7). It is found that quantum size effects lead to the breakdown of the classical Gibbs-Thomson analysis. This is manifested by the lack of scaling of the island densities. In addition, island decay times tau are orders of magnitude faster than expected from the classical analysis and have an unusual dependence on the growth flux F (i.e., tau is approximately 1/F). As a result, a highly monodispersed 7-layer island height distribution is found after coarsening if the islands are grown at high rather than low flux rates. These results have important implications, especially at low temperatures, for the controlled growth and self-organization of nanostructures.

Journal Article↗
PubMed2006

Quasimonoenergetic electron beam generation by using a pinholelike collimator in a self-modulated laser wakefield acceleration.

A relativistic electron bunch with a large charge (>2 nC) was produced from a self-modulated laser wakefield acceleration configuration. For this experiment, an intense laser beam with a peak power of 2 TW and a duration of 700 fs was focused in a supersonic He gas jet, and relativistic high-energy electrons were observed from the strong laser-plasma interaction. By passing the electron bunch through a small pinholelike collimator, we could generate a quasimonoenergetic high-energy electron beam, in which electrons within a cone angle of 0.25 mrad (f/70) were selected. The beam clearly showed a narrow-energy-spread behavior with a central energy of 4.3 MeV and a charge of 200 pC. The acceleration gradient was estimated to be about 30 GeV/m. Particle-in-cell simulations were performed for comparison study and the result shows that both the experimental and simulation results are in good agreement and the electron trapping is initiated by the slow beat wave of the Raman backward wave and the incident laser pulse.

Journal Article↗
PubMed2006

Development and evaluation of triplex PCR for direct detection of mycobacteria in respiratory specimens.

AIMS: To develop a method for the simultaneous detection of Mycobacterium tuberculosis, Mycobacterium avium-intracellularecomplex (MAC), and other mycobacteria in clinical specimens using triplex PCR. METHODS AND RESULTS: The target of amplification was the internal transcribed spacer region between the l6S and 23S rDNA genes. Twenty-two mycobacterial type strains, 118 M. tuberculosis, 87 other mycobacteria, 75 nonmycobacterial pathogens, 115 respiratory specimens from confirmed cases of tuberculous or other mycobacterial diseases, and sputa from 50 patients with nonmycobacterial respiratory diseases were tested. In M. tuberculosis, 322 bp pan-mycobacterial and 133 bp species-specific bands were observed. In MAC, the respective bands were 322 and 84 bp. The other mycobacteria showed single pan-mycobacterial bands of approx. 300-350 bp. Nonspecific amplicons were not found in any of the nonmycobacterial pathogens. In the tuberculosis specimens, 96.4% of smear-positive specimens and 70.2% of smear-negative specimens showed positive reactions. Specimens from two patients with MAC infection were MAC positive. Only 1 of 50 specimens from nonmycobacterial diseases was positive (2.0%). CONCLUSION, SIGNIFICANCE AND IMPACT OF THE STUDY: Triplex PCR enables accurate and rapid diagnosis of tuberculosis and probably is useful for the detection of MAC and other mycobacteria in respiratory specimens.

Bronchoalveolar Lavage Fluid↗
PubMed2006

A comparison of oral health related quality of life between complete and partial removable denture-wearing older adults in Korea.

The purpose of this study was to compare the oral health related quality of life (OHRQoL) between older Korean adults with complete and partial removable dentures using oral health impact profile (OHIP). A pool of 4250 Korean older adults was identified by random stratification by area from the sample cohort of Korean National Survey of Oral Health in the year of 2000. Out of the potential pool, 445 subjects with removable partial dentures (RPDs) or complete dentures (CDs) agreed to be interviewed by telephone. Each question in the survey was about how frequently each event was experienced during the past 12 months. To analyse the association between OHIP scores and removable denture status, bivariable analysis and multiple linear regression analysis were used. RPD users showed higher scores on eight items than CD users. They were 'breath stale', 'food catching', 'sensitive teeth', 'toothache', 'tense', 'unable to brush teeth', 'less tolerant to family members' and 'irritable with others'. RPD users might be associated with higher scores of functional limitation, physical pain and psychological discomfort than CD users. RPD users had slight tendency to be associated with higher OHIP-49 score than CD users, but it was not statistically significant. The findings of the present study confirm that there is no general OHRQoL difference between RPD and CD users. But in the items and subscales of OHIP, RPD users might experience more impaired OHRQoL than CD users.

Age Distribution↗
PubMed2006

Midazolam depresses carotid body chemoreceptor activity.

BACKGROUND: Although the contribution of the gamma-aminobutyric acid (GABA) receptor system in peripheral chemosensation is unclear, immunohistochemistry has demonstrated the presence of GABA-ergic receptors in mammalian carotid bodies. We hypothesized that an activation of the carotid body GABA receptors would counteract the depolarizing effect of hypoxia. METHODS: The carotid body with arterial supply and the carotid sinus nerve was removed en bloc from New Zealand White rabbits and placed in a perfusion chamber. The carotid body preparation was perfused via the cut common carotid artery with a modified Tyrode's solution at a rate of 3.5-4.5 ml/min with a constant pressure of 45 cmH2O. The carotid sinus nerve firing frequency (Hz) was recorded at two different oxygen tension levels during perfusion with midazolam of 1, 10 and 100 microg/l. RESULTS: The frequency was decreased by midazolam in a dose-dependent manner (n = 8). Firing frequencies (mean +/- SEM) at the low oxygen tension level decreased from 643.13 +/- 67.2 Hz in the control to 554.5 +/- 67.7 Hz (P = 0.054 vs. control), 509.01 +/- 100.5 Hz (P < 0.012 vs. control) and 422.6 +/- 77.3 Hz (P < 0.001 vs. control) during perfusion with midazolam of 1, 10 and 100 microg/l, respectively. CONCLUSION: Midazolam depresses carotid body chemoreceptor activity in a dose-dependent manner.

Action Potentials↗
PubMed2006

Fentanyl reduces desflurane-induced airway irritability following thiopental administration in children.

BACKGROUND: Airway irritation is a major drawback of desflurane anesthesia. This study was designed to evaluate the effect of intravenous fentanyl given before thiopental induction on airway irritation caused by a stepwise increase in desflurane in children. METHODS: Eighty children (2-8 years) were enrolled in a randomized, double-blind study. Forty received saline and 40 received 2 microg/kg of fentanyl intravenously; this was followed by thiopental sodium 5 mg/kg in both groups. Patients were assistant-ventilated with desflurane 1%, which was then increased by 1% every six breaths up to 10%. During this period, cough, secretion, excitation and apnea were graded and the desflurane concentration at which airway irritation symptoms first occurred was recorded. The results were analyzed using Pearson's chi-squared test. RESULTS: The incidence of typical airway irritation events was lower with fentanyl than with saline (cough, 2.5% vs. 42.5%; secretion, 27.5% vs. 82.5%; excitation, 10% vs. 82.5%; apnea, 20% vs. 65%; P < 0.05). The mean expired desflurane concentration at which the first airway irritation symptom occurred was greater with fentanyl than with saline (7.3% vs. 5.5%, P < 0.05). CONCLUSIONS: Intravenous fentanyl in children reduces airway complications caused by desflurane.

Analgesics, Opioid↗
PubMed2006

ICA and water in Korea--overview.

The natural water quality in Korea has improved significantly in the last 20 years since major collective national initiatives were implemented by governmental agencies, non-governmental organizations, and professionals among many others. Recently instrumentation, control, and automation (ICA) technology has become one of the most important technologies for carrying out this task. Korea has become especially well known with a strong reputation for information technology and international business with commercial products like semi-conductors, computers, mobile phones, computer games, and other electronic products. In this paper the background of Korean water quality is reviewed and several of the most significant national projects related to ICA are discussed. The major projects may include the Automatic Monitoring Network of River Water Quality and the Integrated Management System of Wastewater Treatment Plants in Upper Basin Area of Multi-purpose Dams.

Automation↗
PubMed2005

Functionality of the TRPV subfamily of TRP ion channels: add mechano-TRP and osmo-TRP to the lexicon!

Transient receptor potential (TRP) ion channels have been identified as cellular sensors responding to diverse external and internal stimuli. This review will cover the TRPV subfamily that comprises vertebrate and invertebrate members. The six mammalian TRPV channels were demonstrated to function in thermosensation, mechanosensation, osmosensation and Ca(2+) uptake. Invertebrate TRPV channels, five in Caenorhabditis elegans and two in Drosophila, have been shown to play a role in mechanosensation, such as hearing and proprioception in Drosophila and nose touch in C. elegans, and in the response to osmotic and chemical stimuli in C. elegans. We will focus here on the role that TRPV ion channels play in mechanosensation and a related sensory (sub-)modality, osmosensation.

Animals↗
PubMed2005

Role of NF-kappaB signaling pathway in increased tumor necrosis factor-alpha-induced apoptosis of lymphocytes in aged humans.

In human aging, lymphocytes display increased sensitivity to tumor necrosis factor-alpha (TNF-alpha)-induced apoptosis. TNF-alpha induces both survival and apoptotic signals. The survival signal is mediated by the activation of NF-kappaB. Although a role of certain proapoptotic molecules in aging has been reported, a role of altered NF-kappaB signaling pathway has not been explored in detail. In this study, we have compared TNF-alpha-induced activation of NF-kappaB, phosphorylation of IkappaBalpha, and the expression of IKKbeta between lymphocytes from young and aged humans. Furthermore, we have explored a role of IKKbeta in increased susceptibility of lymphocytes from aged humans to TNF-alpha-induced apoptosis. Lymphocytes from aged humans displayed decreased activation of NF-kappaB, reduced phosphorylation of IkappaBalpha, and decreased expression of IKKbeta. In addition, overexpression of IKKbeta in lymphocytes from aged humans normalized TNF-alpha-induced apoptosis to the level of young subjects. These data suggest a deficiency of NF-kappaB signaling pathway and a role of IKKbeta, at least in part, for increased sensitivity of lymphocytes from aged humans to TNF-alpha-induced apoptosis.

Adolescent↗
PubMed2005

'Largest angle to target' in surgery for intermittent exotropia.

PURPOSE: To evaluate the safety of the approach based on the notion that the surgical dose for intermittent exotropia should be based on the largest angle ever measured. DESIGN: Prospective case series of 33 patients. METHODS: A total of 33 patients with intermittent exotropia, in whom angles of misalignment at distance or near showed a difference of 15 prism diopters (PD) or more among visits, were included. All the patients were treated by bilateral lateral rectus recession by the same surgeon (JMH), and all were followed up for a minimum of 6 months postoperatively. Short- and long-term surgical results after the initial procedure for intermittent exotropia were analysed. RESULTS: The short-term average result at a postoperative 1 week was 9.3 PD esotropia at distance (range 30 esotropia-16 exotropia). The long-term average results postoperative 6 or 9 months were 4.8 PD exotropia at distance (range 12 esotropia-30 exotropia). At the last follow-up, no overcorrection over 2 PD esophoria at distance was found, and 9 PD of intermittent esotropia and esophoria at near was observed in two patients, respectively. CONCLUSIONS: The strategy of surgical dose for intermittent exotropia based on the largest angle ever measured did not result in overcorrections and is believed to be safe.

Child↗
PubMed2005

Effect of cryoprotectants on the reconstitution of surfactant-free nanoparticles of poly(DL-lactide-co-glycolide).

Various cryoprotectants were tested to reconstitute the surfactant-free nanoparticles of poly(DL-lactide-co-glycolide) (PLGA). When 2.0% (w/v) of sucrose, trehalose and lactose were used, nanoparticles were completely reconstituted into aqueous solution and particle size was not significantly changed. Above 1.0% (w/v) of sucrose, trehalose and lactose, nanoparticles are well reconstituted whereas it was precipitated with 1.0% (w/v) of mannitol. Drug-encapsulated surfactant-free nanoparticles were quite reconstituted when 2.0% (w/v) of sucrose, trehalose and lactose. Drug release kinetics of nanoparticles was not significantly changed by cryoprotectants.

Cryoprotective Agents↗
PubMed2005

Extrapedicular approach of percutaneous vertebroplasty in the treatment of upper and mid-thoracic vertebral compression fracture.

PURPOSE: To evaluate the clinical outcome of the extrapedicular approach of percutaneous vertebroplasty (PVP) for upper and mid-thoracic vertebral compression fractures in patients. MATERIAL AND METHODS: Extrapedicular vertebroplasty was performed in painful compression fractures at T4-T8 levels. The assessment criteria were changes over time in visual analog scale (VAS) and mobility score. We evaluated the volume of cement injected, the size of needle required, and complications. RESULTS: Procedures were performed in 27 patients with a total of 34 affected vertebral bodies. Early (within a week) and one year later, clinical follow-ups showed that pain intensity had decreased by 50% one day after operation and later by 70-80%. Mobility scores of all patients were improved immediately after the procedure. Average volume of polymethylmethacrylate (PMMA) per vertebral body was 3.8 +/- 1.2 ml. Leakage of PMMA occurred in one vertebral level (intradiskal space), but did not cause clinical complications. CONCLUSION: PVP of upper and mid-thoracic spine with an extrapedicular approach is an efficient and safe procedure for treating painful thoracic vertebral compression fracture under a cautious patient selection and meticulous technical procedure.

Aged↗