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Biomedical subjects

K H Kim

Publications and source records attributed to K H Kim.

At least 37 records · Page 2Linked to original sources
PubMed2006

Multidetector-row CT angiography of cerebral vasospasm after aneurysmal subarachnoid hemorrhage: comparison of volume-rendered images and digital subtraction angiography.

BACKGROUND AND PURPOSE: Cerebral vasospasm remains a major problem in patients recovering after surgical treatment of cerebral aneurysms. The purpose of this study was to evaluate cerebral vasospasm at multidetector-row spiral CT angiography (MDCTA) compared with digital subtraction angiography (DSA) in patients with aneurysmal subarachnoid hemorrhages (SAHs). METHODS: Seventeen patients suspected of having vasospasm on clinical findings underwent both postoperative MDCTA and DSA. MDCTA was analyzed by using volume-rendered images as well as axial images. A total of 251 arterial segments were analyzed for vasospasm by using a 5-point grading system. The MDCTA results were then compared with findings on the corresponding DSA images. Sensitivity, specificity, and accuracy of MDCTA for detection of hemodynamically significant spasms were also calculated, with findings at DSA used as the reference standard. RESULTS: On DSA, 74 spasmatic segments were found among the 251 segments evaluated, and 40 segments with hemodynamically significant vasospasms were present. The overall agreement between MDCTA and DSA was 95.2%. We had 12 (4.8%) cases of disagreement between MDCTA and DSA. In 11 segments, the degree of stenosis was overestimated at MDCTA. Overall accuracy, sensitivity and specificity of MDCTA in the detection of hemodynamically significant vasospasm were 97.5%, 98.1%, and 98.0%, respectively, with positive and negative predictive values of 90.7% and 99.5%. CONCLUSION: MDCTA appears to be a reliable alternative imaging technique to DSA in the assessment of patients with cerebral vasospasm after aneurysmal SAH.

Adult↗
PubMed2005

Methanolic extract of Pterocarpus santalinus induces apoptosis in HeLa cells.

Ptercarpus santalinus (Fabaceae) has been used as a folk remedy in Korea, and it has been shown to exhibit antiinflammations, antiulcers and anticancer effects. In this study, therefore, we report the cytotoxic activity and the mechanism of cell death exhibited by the methanol extract of Ptercarpus santalinus (MEPS) against human cervical adenocarcinoma cell line, HeLa. Treatment of HeLa cells with various concentrations of MEPS resulted in growth inhibition and induction of apoptosis in a dose-dependent manner as determined by cell viability, chromatin condensation, DNA fragmentation and sub-G1 phase accumulation. In Western blot analysis, apoptosis in the HeLa cells was associated with the release of cytochrome C from mitochondria into the cytosol, activation of caspases-3, -8, -9 and proteolytic cleavage of PARP. These results suggest that MEPS exhibits antiproliferative effect on HeLa cells via apoptosis, and it may be a potential candidate in field of anticancer drug discovery.

Apoptosis↗
PubMed2005

Inhomogeneous level splitting in Pr 2-x BixRu2O7.

We report that Bi doping drives Pr 2-x BixRu2O7 from an antiferromagnetic insulator (x = 0) to a metallic paramagnet (x approximately 1) with a broad low T maximum in C/T. Neutron scattering reveals local low energy spin excitations (variant Planck's omega approximately 1 meV) with a spectrum that is unaffected by heating to k(B)T >> variant Planck's omega. We show that a continuous distribution of splittings of the non-Kramers Pr3+ ground-state doublet such as might result from various types of lattice strain can account for all the data.

Journal Article↗
PubMed2005

Spatial chemical inhomogeneity and local electronic structure of Mn-doped Ge ferromagnetic semiconductors.

We have investigated the chemical distributions and the local electronic structure of potential diluted magnetic semiconductor Ge0.94Mn0.06 single crystals using scanning photoelectron microscopy (SPEM), x-ray absorption spectroscopy (XAS), and photoemission spectroscopy (PES). The SPEM image shows the stripe-shaped microstructures, which arise from the chemical phase separation between the Mn-rich and Mn-depleted phases. The Mn 2p XAS shows that the Mn ions in the Mn-rich region are in the divalent high-spin Mn2+ states but that they do not form metallic Mn clusters. The Mn 3d PES spectrum exhibits a peak centered at approximately 4 eV below E(F) and the negligible spectral weight near E(F). This study suggests that the observed ferromagnetism in Ge1-xMnx arises from the phase-separated Mn-rich phase.

Journal Article↗
PubMed2005

Muon-spin-rotation measurements of the penetration depth of the infinite-layer electron-doped Sr0.9La0.1CuO2 cuprate superconductor.

Muon-spin-rotation (muSR) measurements of the in-plane penetration depth lambda(ab) have been performed in the infinite-layer electron-doped Sr0.9La0.1CuO2 high-T(c) superconductor (HTS). Absence of the magnetic rare-earth ions in this compound allowed us to measure for the first time the absolute value of lambda(ab)(0) in electron-doped HTSs using muSR. We found lambda(ab)(0)=116(2) nm. The zero-temperature depolarization rate sigma(0) proportional, variant 1/lambda(2)(ab)(0)=4.6(1) micros(-1) is more than 4 times higher than expected from the Uemura line. Therefore, this electron-doped HTS does not follow the Uemura relation found for hole-doped HTSs.

Journal Article↗
PubMed2005

Immunochemical and biological analysis of allergenicity with excretory-secretory products of anisakis simplex third stage larva.

BACKGROUND: Anisakis simplex third stage larvae (L3) are parasites that frequently give rise to allergic responses. The larvae molt into fourth stage larvae (L4), and at each stage they produce L3-excretory-secretory products (L3-ESP) and L4-ESP, respectively, which are different in their main protein constituents. Although the allergenicity of L4-ESP has been investigated by several research groups, research on the allergenicity of L3-ESP has not been carried out by any researcher. In this investigation, the allergenicity and antigenicity of L3-ESP were investigated in comparison with L4-ESP, using rat sera. METHODS: Rat sera were produced by L3 oral infection two times with a 9-week interval. Larvae ESP prepared by culture were concentrated and fractioned using lyophilizer and a centrifugal filter device, respectively. Immunochemical analysis was performed using both indirect ELISA and immunoblot. Biological allergenicity was analyzed by RBL-2H3 exocytosis. RESULTS: With the indirect ELISA, the optical density (OD) value of the nonfractioned (NF)-L3ESP was only one third of that of the NF-L4ESP in both specific IgM and IgG. On measuring specific IgE, the OD of NF-L3ESP was less than one tenth of that of NF-L4ESP. In addition, neither antigen nor allergen was shown in NF-L3ESP, but it was shown in NF-L4ESP with immunoblot. However, the biological allergenicity of NF-L3ESP was comparable to that of NF-L4ESP. To demonstrate the presence of any allergen, L3-ESP was fractioned and found to carry twelve visualized allergen bands from 10 to 186 kDa by immunoblot. CONCLUSIONS: These results indicate that L3-ESP may include the important allergens necessary to induce the allergy by L3 oral infection, as compared to L4-ESP.

Allergens↗
PubMed2005

Design of antagonists for NMDA and AMPA receptors.

Determinants of antagonism of NMDA and calcium permeable AMPA receptor channels by organic cations were studied using several homologous series of mono- and dicationic derivatives of adamantane, phenylcyclohexyl, triphenylmethane, diphenylmethane. Antagonism by these drugs was studied on native receptors of isolated rat brain neurons and on recombinant GluR1 receptors expressed by Xenopus oocytes. The major action of these compounds was on the open channel, although minor competitive or closed channel antagonism cannot be ruled out. Analysis of structure-activity relationships suggests that all organic monocations are selective antagonists of NMDA receptors. Compounds exhibiting trapping block are more potent than those exhibiting weakly-trapping block. AMPA and NMDA receptor channels are blocked by dicationic organic compounds, the former requiring a certain distance between the hydrophobic moiety and the terminal charged group. Variations of their terminal ammonium group demonstrated that trimethylammonium derivatives are the most potent antagonists of AMPA receptors, whereas the terminal amino group is optimal for block of NMDA receptors. Based on the action of 38 compounds, topographical models of the binding sites of these compounds on NMDA and AMPA receptor channels are presented. These models will help to design channel-blocking drugs with defined potency and selectivity of action.

Adamantane↗
PubMed2005

Refined suture techniques to prevent bleeding from accidental slippage of vascular clamps during living donor hepatectomy.

Accidental slippage of vascular clamps during living donor hepatectomy can induce brisk bleeding and even imperil the donor. After practicing more than 1000 cases of living donor hepatectomy, the investigators realized that specialized suture techniques were important to secure the vascular closure to prevent unnecessary bleeding. For secure division of intrahepatic vein branches, we devised a continuous penetration suture method in which the orders of procedures were changed to clamping-closure-cut sequence. For secure division of the main and accessory hepatic vein branches from the inferior vena cava, we applied stay sutures at each corner and midpoint of the hepatic vein stump so as not to permit its slippage. After application of these methods, we did not experience any episode of accidental clamp slippage. We are sure that these suture techniques are beneficial to prevent unnecessary bleeding during living donor hepatectomy and to make surgeons feel at ease during the living donor operation.

Blood Loss, Surgical↗
PubMed2005

Complete sequence and structure of the mitochondrial genome of the human tapeworm, Taenia asiatica (Platyhelminthes; Cestoda).

The complete Taenia asiatica mitochondrial genome was amplified by long extension polymerase chain reaction (long PCR) to yield overlapping fragments that were then completely sequenced. The whole mitochondrial genome was 13 703 bp long and contained 12 protein-encoding, 2 ribosomal RNA (small and large subunits), 22 transfer RNA genes and a short non-coding region. Thus, its gene contents are like those typically found in metazoan animal mitochondrial genomes (apart from the absence of atp8). All the genes were transcribed from the same strand. The 3' end 34 bp region of nad4L overlapped with the 5' end portion of nad4. The tRNA genes were 61-69 bp long, and the secondary structures of 18 tRNAs had typical clover-leaf shapes with paired DHU arms. However, trnC, trnS1, trnS2 and trnR had unpaired DHU arms that were 7-12 bp in length. The tRNAs that transferred serine lacked a DHU arm, as is also observed in a number of parasitic platyhelminths and metazoans. However, the trematode trnRs have paired DHU arms. The T. asiatica mtDNA non-coding region was like that in other cestodes since it was composed of a short non-coding region of 72 nucleotides and a long non-coding region of 176 nucleotides separated by a trnL1/, trnS2/, trnL2/, trnR/, nad5 gene cluster. The sequences of the cox1 genes between T. asiatica and T. saginata differ by 4.6%, while the T. asiatica cob gene differs by 4.1% and 12.9% from the cob genes of T. saginata and T. solium, respectively. In conclusion, the T. asiatica mitocondrial genome should provide a resource for comparative mitochondrial genomics and systematic studies of parasitic cestodes.

Animals↗
PubMed2005

Intussusception after gastric surgery.

Intussusception following gastric surgery is a rare postoperative complication. It may develop in clinical situations following gastroenterostomy, Billroth II gastric surgery with or without Braun anastomosis, or Roux-en-Y gastrojejunostomy. The patients may present with either an acute surgical emergency or with a chronic, relapsing form. The mortality may be up to 50 % in these cases if not treated appropriately, but little is known about the mechanism underlying the condition. Early diagnosis with a high index of suspicion and prompt treatment of the acute form are therefore important. Surgical reduction with laparotomy is mandatory, although definitive corrective and preventative measures have not yet been established.

Adult↗
PubMed2005

Intra- and extra-pericardial lengths of the superior vena cava in vivo: implication for the positioning of central venous catheters.

To reduce the possibility of cardiac tamponade, a rare but lethal complication of central venous catheters, the tip of the central venous catheter should be located above the cephalic limit of the pericardial reflection, not only above the superior vena cava-right atrium junction. This study was performed to measure the superior vena cava lengths above and below the pericardial reflection in cardiac surgical patients. Cardiac surgical patients (n = 61; 27 male), whose age [mean +/- SD (range)] was 47 +/- 15 (15-75) years, were studied. The intrapericardial and extrapericardial lengths, and the length of the medial duplicated part were measured separately. The whole vertical lengths of the superior vena cava on either side were calculated respectively by adding the intra-and extrapericardial and medial duplication lengths. The lateral extrapericardial was 29.1 +/- 6.5 (Mean +/- SD) (9-49) mm (range), and lateral extrapericardial length was 32.6 +/- 6.9 (20-53) mm. The medial extrapericardial length was 23.3 +/- 5.0 (11-39) mm, medical duplicated length was 7.2 +/- 3.3 (4-20) mm, and medial intrapericardial was 28.3 +/- 7.0 (20-52) mm. The averaged superior vena cava length of both sides was 60.3 +/- 9.0 (44.5-90) mm. Almost half of the superior vena cava was found to be within the pericardium and half out. This information may be helpful in deciding how far a central venous catheter should be withdrawn beyond the superior vena cava-right atrial junction during right atrial electrocardiographic guided insertion, and in the prediction of optimal central venous catheter insertion depth.

Adolescent↗
PubMed2004

The study on photoreflectance characteristic of semi-insulating GaAs surface region by its exposure to 6 MeV electron beam.

Photoreflectance measurements were performed to investigate the optical properties in the electron beam irradiation semi-insulating GaAs(e-beam irradiation GaAs) and semi-insulating GaAs(SI-GaAs). A considerable increase of the PR amplitudes has been registered after the e-beam irradiation in comparison with the GaAs. It is that result of a higher electron scattering on the lattice defects created by the e-beam.

Arsenicals↗
PubMed2004

Competing magnetic phases on a kagomé staircase.

We present thermodynamic and neutron data on Ni3V2O8, a spin-1 system on a kagomé staircase. The extreme degeneracy of the kagomé antiferromagnet is lifted to produce two incommensurate phases at finite T--one amplitude modulated, the other helical--plus a commensurate canted antiferromagnet for T-->0. The H-T phase diagram is described by a model of competing first and second neighbor interactions with smaller anisotropic terms. Ni3V2O8 thus provides an elegant example of order from subleading interactions in a highly frustrated system.

Journal Article↗
PubMed2004

Partial trisomy of chromosome 10(q22-q24) due to maternal insertional translocation (15;10).

Interchromosomal insertional translocations are rare chromosome rearrangements with an incidence of about 1:80,000 live births. We report on the clinical and cytogenetic findings of a newborn baby with partial trisomy 10q22-10q24 due to a maternal insertional translocation 15;10. Partial trisomy of the long arm of chromosome 10 is a distinctive chromosome aberration characterized by prenatal-onset growth retardation and craniofacial, skeletal, and other somatic anomalies. Most cases are unbalanced products from reciprocal chromosome translocations, and insertional translocations are rarely involved. The proband was initially referred because of severe intrauterine growth retardation, and fluorescence in situ hybridization (FISH) using painting probes confirmed the maternal balanced (15;10) insertion.

Abnormalities, Multiple↗
PubMed2004

Nexus between quantum criticality and phase formation in U(Ru1-xRhx)2Si2.

Simplification of the magnetic field-versus-temperature phase diagram and quantum criticality in URu2Si2 dilutely doped with Rh are studied by measuring the magnetization and resistivity in magnetic fields of up to 45 T. For x=4%, the hidden order is completely destroyed, leaving a single field-induced phase II. A correlation between the field dependence of this phase and that of the quantum critical point, combined with the suppression of the T2 coefficient of the resistivity within it, implicates field-tuned quantum criticality as an important factor in phase formation.

Journal Article↗
PubMed2004

Core-level x-ray photoemission satellites in ruthenates: a new mechanism revealing the Mott transition.

Core-level x-ray photoemission spectra for the Mott-Hubbard systems are calculated by the dynamical mean-field theory based on the exact diagonalization method. The spectra show a two-peak structure, screened and unscreened peaks. The screened peak is absent in a Mott insulator, but develops into the main peak when the correlation strength becomes weak and the system turns metallic. The calculated spectral behavior is consistent with the experimental Ru 3d core-level spectra of various ruthenates. This new mechanism of the core-level photoemission satellite can be utilized to reveal the Mott transition phenomenon in various strongly correlated electron systems, especially in nanoscale devices and phase-separated materials.

Journal Article↗
PubMed2004

Charge-density waves survive the Pauli paramagnetic limit.

Measurements of the resistance of single crystals of (Per)2Au(mnt)2 have been made at magnetic fields B of up to 45 T, exceeding the anticipated Pauli paramagnetic limit of Bp approximately 37 T. The continued presence of nonlinear charge-density wave electrodynamics at B> or =37 T establishes the survival of the charge-density wave state above this limit, and the probable emergence of an inhomogeneous phase analogous to that anticipated to occur in superconductors.

Journal Article↗