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Biomedical subjects

S Kim

Publications and source records attributed to S Kim.

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

Decision algorithm based on data mining for coagulant type and dosage in water treatment systems.

Water shortages are gradually accelerating because higher standards of living are required and water resources are more heavily utilised. Therefore, effective water treatment is necessary in order to retain the required quality and amount of water. General treatment includes coagulation, flocculation, filtering and disinfection. Coagulation, flocculation and disinfection are major components of water treatment processes. In this paper, a new automatic decision algorithm is proposed for coagulation. The proposed method shows how to determine the coagulant type and amount using data mining techniques.

Algorithms↗
PubMed2006

Efficient design and operation of a data acquisition system for pressurized pipeline systems.

The unsteady flow analysis of pipeline systems provides useful guidelines for implementing data acquisition components such as data filtering ranges, sensor locations and sampling frequencies. A theoretical integration among hydraulics, free vibration analysis and signal processing is proposed for a comprehensive approach aiming at enhanced design and operation of data acquisition system. Transient analysis is performed to extract flow variation by a valve modulation in a pipeline system. Frequency transformation analysis is developed to convert pressure variations between time domain and frequency domain. Free vibration analysis provides spatial distribution of impedance characteristics and pressure variation for determining optimum sensor location. A real-time filter can be designed to secure valid signals of any particular unsteady event. Hypothetical and experimental applications show that the proposed method has potentials of the leakage detection of a pipeline system as well as an efficient design of data acquisition system.

Equipment Failure Analysis↗
PubMed2006

Characteristics of sludge reduction in an integrated pretreatment and aerobic digestion process.

In this study, integrated pretreatments and aerobic digestion processes were investigated in order to provide a feasible alternative that can achieve effective sludge reduction. An ozone treatment in the presence of ionic manganese, a catalyst, increased the sludge reduction ratio three times higher than that of a single ozonation, presumably due to an increase in OH radical production. The ozone treatment yielded the effective sludge reduction ratio with an increasing ozone dosage, and an effective dosage of the catalyst was found to be 4 mg-Mn/g-TS. When a mechanical pretreatment and an ozone/catalyst were applied in a series, the integrated process, even at a half mechanical intensity and a half level of ozone dosage, showed higher and faster sludge reduction than each single process did. In addition, the integrated pretreatment process showed the highest dewaterability of the treated sludges. A ratio of sludge cake generation, which was newly introduced to quantify overall performance of sludge treatment processes, showed that the integrated pretreatment followed by the aerobic digestion yielded approximately a half of the sludge cake volume compared to the single aerobic digestion. Therefore, the integrated pretreatment can be a feasible method for the effective reduction of total suspended solid and the final volume.

Aerobiosis↗
PubMed2006

Detection of Escherichia coli O157:H7 and Salmonella typhimurium using filtration followed by Fourier-transform infrared spectroscopy.

Fourier-transform infrared spectroscopy has been successfully used as a nondestructive method for identifying, distinguishing, and classifying pathogens. In this study, a less time-consuming Fourier-transform infrared procedure was developed to identify Escherichia coli O157:H7 and Salmonella Typhimurium. Samples containing 10(9) CFU/ml were prepared in tryptic soy broth and then serially diluted (up to eight times) to obtain bacterial solutions of 10(9) to 10 CFU/ml. These dilutions were incubated at 37 degrees C for 6 h, samples were filtered through a Metricel filter hourly (for 0 to 6 h), and spectra were obtained using a ZnSe contact attenuated total reflectance accessory on a Continu mum infrared microscope. Midinfrared spectra (4,000 to 700 cm(-1)) of Salmonella Typhimurium and E. coli O157:H7 were generated, and peak areas in the region of 1,589 to 1,493 cm(-1) were used to detect the pathogens. Initially, detection limits were between 10(6) and 10(7) CFU/ml without preenrichment, and samples starting with 500 CFU/ml were detectable following incubation for 6 h, when counts reached at least 10(6) CFU/ ml. Compared with results of previously published studies in which Fourier-transform infrared spectroscopy was used to identify select pathogens, this method is more rapid and less expensive for practical large-scale sample analysis.

Colony Count, Microbial↗
PubMed2005

APOE epsilon2/epsilon4 polymorphism and cerebral microbleeds on gradient-echo MRI.

The association of APOE genotypes with cerebral microbleeds (CMBs) was examined on the basis of the location of CMBs in 414 patients who were admitted primarily because of stroke. With respect to possession of the epsilon2 or epsilon4 allele, the adjusted odds ratio was 1.94 (1.05 to 3.58) for lobar CMBs but 1.21 (0.69 to 2.11) for nonlobar CMBs. This suggests that the pathogenesis of CMBs may differ depending on their location.

Age Factors↗
PubMed2005

Nitric oxide stimulates a large-conductance Ca-activated K+ channel in human skin fibroblasts through protein kinase G pathway.

In order to investigate the large-conductance Ca(2+)-activated K(+) (BK(Ca)) channel and determine the effects of nitric oxide (NO) on the channel in human skin fibroblasts, we performed electrophysiological patch clamp recordings on 5th-passage cells of human genital skin cultures. The whole-cell outward K(+) current was increased with depolarization, and proved to be sensitive to NS1619 (a selective BK(Ca) channel activator) and iberiotoxin (a specific BK(Ca )channel inhibitor). The single-channel currents showed 226 pS of mean conductance in symmetrical K(+). Sodium nitroprusside (SNP; an NO donor) significantly increased the K(+) current amplitude in the whole-cell mode, and open probability of the channel (NPo) in the cell-attached mode, but not in the inside-out mode. S-nitroso-N-acetylpenicillamine (an NO donor) and 8-Br-cGMP (a membrane-permeant cGMP analogue) also increased the BK(Ca )channel activity. The stimulatory effect of SNP on BK(Ca) channels was inhibited by pretreatment with 1H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-1-one (a soluble guanylyl cyclase inhibitor), or KT5823 [a specific protein kinase G (PKG) inhibitor]. Cytoplasmic PKG also increased the channel activity in inside-out patches. In conclusion, the present data indicate that BK(Ca) channels constitute a significant fraction of K(+) current in human skin fibroblasts, and that NO increases NPo of BK(Ca) channels, which are mediated via the cGMP/PKG pathway, without direct effects on the channel.

Benzimidazoles↗
PubMed2005

Interleukin 4 and prolonged hypoxia induce a higher gene expression of lysyl hydroxylase 2 and an altered cross-link pattern: important pathogenetic steps in early and late stage of systemic scleroderma?

The major pathological processes of systemic scleroderma (SSc) comprise inflammation and microvascular damage in the early or acute progressive stage as well as tissue fibrosis and hypoxia in the chronic end stage. Fibrosis seems to be a general phenomenon characterized by an increase of hydroxylysine aldehyde derived collagen cross-links which has been shown in vitro for systemic scleroderma fibroblasts. In the present study, we analyzed the cross-link pattern and the gene expression of lysyl hydroxylase 2 (LH2) in the skin of SSc. Furthermore, we determined the modulatory impact of inflammatory cytokines (interleukin 4, TNF- alphaand interleukin 1alpha/beta) and prolonged hypoxia on the cross-link profile and the gene expression of LH2, respectively. The concentration of hydroxylysine aldehyde derived cross-links was significantly increased in SSc, while the level of lysine aldehyde derived cross-links was not changed. Accordingly, a marked increase of the transcriptional level of LH2 was found. In long term dermal fibroblast cultures, only interleukin 4 induced an increase of hydroxylysine aldehyde derived cross-links accompanied by a higher gene expression of LH2. Furthermore, prolonged hypoxia induced a marked increase of the mRNA level of LH2 in relation to collagen I. The skin of SSc is characterized by an increase of the transcriptional activity of LH2 leading to an altered cross-link pattern. The changes in the quality of the collagenous matrix can also be obtained in cell culture by the exposure of fibroblasts to interleukin 4 or prolonged hypoxia emphasizing the role of this mediator in the acute and the low oxygen tension in the chronic phase of the disease.

Cell Hypoxia↗
PubMed2005

The Akt inhibitor KP372-1 suppresses Akt activity and cell proliferation and induces apoptosis in thyroid cancer cells.

The phosphatidylinositol 3' kinase (PI3K)/phosphatase and tensin homologue deleted on chromosome ten/Akt pathway, which is a critical regulator of cell proliferation and survival, is mutated or activated in a wide variety of cancers. Akt appears to be a key central node in this pathway and thus is an attractive target for targeted molecular therapy. We demonstrated that Akt is highly phosphorylated in thyroid cancer cell lines and human thyroid cancer specimens, and hypothesised that KP372-1, an Akt inhibitor, would block signalling through the PI3K pathway and inhibit cell proliferation while inducing apoptosis of thyroid cancer cells. KP372-1 blocked signalling downstream of Akt in thyroid tumour cells, leading to inhibition of cell proliferation and increased apoptosis. As thyroid cancer consistently expresses phosphorylated Akt and KP372-1 effectively blocks Akt signalling, further preclinical evaluation of this compound for treatment of thyroid cancer is warranted.

Apoptosis↗
PubMed2005

Effects of eplerenone on transcriptional factors and mRNA expression related to cardiac remodelling after myocardial infarction.

OBJECTIVE: To examine the effects of eplerenone, a selective aldosterone blocker, on cardiac function after myocardial infarction (MI) and myocardial remodelling related transcriptional factors and mRNA expression in non-infarcted myocardium. METHODS: MI was induced by ligation of the coronary artery in Wistar rats. Rats were randomly assigned to a vehicle treated group or an eplerenone treated group (100 mg/kg/day). RESULTS: At four weeks after MI, left ventricular (LV) end diastolic pressure, LV weight, and LV end diastolic dimension were increased in MI rats. Eplerenone significantly reduced the increase in LV end diastolic pressure, LV weight, and LV end diastolic dimension. In the MI rats the decreased ejection fraction indicated systolic dysfunction and the increased E wave to A wave ratio and E deceleration rate indicated diastolic dysfunction. Eplerenone significantly attenuated this systolic and diastolic dysfunction. Myocardial interstitial fibrosis, transcriptional activities of activator protein 1 and nuclear factor kappaB, and mRNA expression of monocyte chemoattractant protein 1, plasminogen activator inhibitor 1, atrial natriuretic peptide, brain natriuretic peptide, and collagen types I and III were significantly increased at four weeks after MI. Eplerenone significantly attenuated interstitial fibrosis and suppressed transcriptional activity and mRNA expression of these genes. CONCLUSIONS: When administered after MI, eplerenone prevents cardiac remodelling accompanied by systolic and diastolic dysfunction and inhibits abnormal myocardial transcriptional activities and gene expression.

Animals↗
PubMed2005

Evidence for muon neutrino oscillation in an accelerator-based experiment.

We present results for nu(mu) oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced nu(mu) beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy-dependent disappearance of nu(mu), which we presume have oscillated to nu(tau). The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma).

Journal Article↗
PubMed2005

Dielectric studies of molecular motions in amorphous solid and ultraviscous acetaminophen.

The dielectric permittivity and loss spectra of glassy and ultraviscous states of acetaminophen have been measured over the frequency range 10 Hz-0.4 MHz. The relaxation spectra show an asymmetric distribution of times expressed in terms of the Kohlrausch exponent, beta, which remains constant at 0.79+/-0.02 over the 305-341 K range. The dielectric relaxation time increases on cooling according to the Vogel-Fulcher-Tammann equation. However, the values of the parameters are considerably different from the values deduced from earlier work by other researchers using the heat capacity of ultraviscous acetaminophen and relating it to its molecular mobility. The calorimetric glass softening temperature of 296 K obtained from differential scanning calorimetry is close to the value measured from dielectric relaxation. The equilibrium permittivity of ultraviscous acetaminophen decreases on heating like that of a normal dipolar liquid, as anticipated from the Curie law. But, its value decreases rapidly with time when it begins to crystallize. The equilibrium permittivity of this crystal phase is approximately 3.1 at 300 K and increases with temperature, which indicates a partial, orientational-disordering of its structure. The results show limitations of the procedures used in the modeling of the kinetics of molecular motions, that is, estimating physical stability, using thermodynamic considerations based on thermal analyses of the amorphous solid phase of acetaminophen.

Acetaminophen↗
PubMed2005

The analysis of telomere length and telomerase activity in cloned pigs and cows.

Inefficiency in the production of cloned animals is most likely due to epigenetic reprogramming errors after somatic cell nuclear transfer (SCNT). In order to investigate whether nuclear reprogramming restores cellular age of donor cells after SCNT, we measured telomere length and telomerase activity in cloned pigs and cattle. In normal pigs and cattle, the mean telomere length was decreased with biological aging. In cloned or transgenic cloned piglets, the mean telomere length was elongated compared to nuclear donor fetal fibroblasts and age-matched normal piglets. In cloned cattle, no increases in mean telomere length were observed compared to nuclear donor adult fibroblasts. In terms of telomerase activity, significant activity was observed in nuclear donor cells and normal tissues from adult or new-born pigs and cattle, with relatively higher activity in the porcine tissues compared to the bovine tissues. Cloned calves and piglets showed the same level of telomerase activity as their respective donor cells. In addition, no difference in telomerase activity was observed between normal and transgenic cloned piglets. However, increased telomerase activity was observed in porcine SCNT blastocysts compared to nuclear donor cells and in vitro fertilization (IVF)-derived blastocysts, suggesting that the elongation of telomere lengths observed in cloned piglets could be due to the presence of higher telomerase activity in SCNT blastocysts. In conclusion, gathering from the comparative studies with cattle, we were able to demonstrate that telomere length in cloned piglets was rebuilt or elongated with the use of cultured donor fetal fibroblasts.

Animals↗
PubMed2005

[PM-Scl antibody positive systemic sclerosis associated with inclusion-body myositis].

We describe a 72- year-old patient with a ten year history of anti-PM-Scl positive systemic sclerosis associated with inclusion-body myositis. While the association of dermatomyositis and polymyositis with anti-PM-Scl positive systemic sclerosis is frequently reported, inclusion-body myositis was, to the best of our knowledge, only previously described once in association with anti-PM-Scl-positive systemic sclerosis. The distinction between inclusion-body myositis and other forms of inflammatory myopathy, like the histopathologically well distinguishable polymyositis or dermatomyositis, is relevant because of the poor response of inclusion- body myositis to immunosuppressive treatment. Our case underlines that in patients with anti-PM-Scl-positive systemic sclerosis and treatment resistant progressive myopathy the diagnosis of inclusion body myositis should be considered.

Aged↗
PubMed2005

The role of follow-up endoscopy after total gastrectomy for gastric cancer.

BACKGROUND: Follow-up endoscopy after total gastrectomy for gastric cancer is commonly performed without there being any definite evidence of clinical relevance. Therefore, we investigated the role of the upper endoscopic examinations after total gastrectomy for gastric cancer. METHODS: The medical records of 212 early gastric cancer (EGC) patients and 622 advanced gastric cancer (AGC) patients who underwent follow-up endoscopic examination after total gastrectomy between 1994 and 2001 were reviewed. RESULTS: Two of 212 EGC patients and 233 of 622 AGC patients revealed tumour recurrence at all sites. All the endoscopically accessible local tumour recurrences (n=24) were found in the AGC group. Anastomosis site stenosis was detected in 72 of 834 patients. CONCLUSION: Follow-up endoscopy after total gastrectomy for gastric cancer is useful in detecting complications and tumour recurrence. However, this procedure has a limited role in the clinical management and overall survival for patients with recurrent gastric adenocarcinoma.

Adenocarcinoma↗
PubMed2005

ESHAP plus G-CSF as an effective peripheral blood progenitor cell mobilization regimen in pretreated non-Hodgkin's lymphoma: comparison with high-dose cyclophosphamide plus G-CSF.

The ESHAP (etoposide, methylprednisolone, high-dose cytarabine, and cisplatin) regimen has been shown to be effective as an active salvage therapy for lymphoma. Mobilizing stem cells following ESHAP should decrease time to transplantation by making separate mobilizing chemotherapy (MC) unnecessary, while controlling a patient's lymphoma. We therefore assessed the mobilization potential of ESHAP plus G-CSF in 26 patients (ESHAP group) with non-Hodgkin's lymphoma (NHL) and compared these results with those of 24 patients with NHL who received high-dose (4 g/m2l) cyclophosphamide (HDCY) as MC (HDCY group). The age, sex, and radiotherapy to the axial skeleton were well matched between groups, but the number of patients with poor mobilization predictors was higher in the ESHAP group. Significantly higher numbers of CD34+ cells (x 10(6)/kg) (17.1+/-18.8 vs 5.8+/-5.0, P=0.03) and apheresis day 1 CD34+ cells (x 10(6)/kg) (5.5+/-6.6 vs 1.7+/-2.0, P=0.014) were collected from the ESHAP group than from the HDCY group, and the number of patients who achieved an optimal CD34+ cell target of 5 x 10(6)/kg was higher in the ESHAP group (81 vs 50%, P=0.022). Log-rank test revealed that time to target peripheral blood progenitor cell collection (> or =5 x 10(6)/kg) was shorter in the ESHAP group (P=0.007). These results indicate that ESHAP plus G-CSF is an excellent mobilization regimen in patients with relapsed and poor-risk aggressive NHL.

Adolescent↗
PubMed2005

Treatment of relapsed acute lymphoblastic leukemia after allogeneic bone marrow transplantation with chemotherapy followed by G-CSF-primed donor leukocyte infusion: a prospective study.

Donor leukocyte infusion (DLI) alone has very limited efficacy for patients with acute lymphoblastic leukemia (ALL) who have relapsed after allogeneic bone marrow transplantation (BMT). We, therefore, prospectively tested the efficacy of cytoreductive chemotherapy (intermediate-dose cytarabine+idarubicin+etoposide) followed immediately by G-CSF-primed DLI (Chemo-DLI) in 10 relapsed ALL patients after allogeneic BMT. Seven achieved complete remission (CR) at a median of 25 days (19-73 days) after DLI. Of these seven CR patients, only one remains alive in CR 907 days after DLI. Two CR patients died in CR of graft-versus-host disease. The remaining four CR patients relapsed at a median of 153 days (120-991 days) after DLI. One is alive with leukemia at post-DLI day 1217. The median survival duration after DLI was 175 days (15-1217 days). In summary, although Chemo-DLI for relapsed ALL after allogeneic BMT induced a relatively high CR rate, durable remissions were rare. Although our data should be interpreted cautiously considering the small number of patients, these results suggest that poor outcome of DLI in relapsed ALL may be primarily due to intrinsic resistance to graft-versus-leukemia effect rather than to the rapid pace of the disease.

Adult↗
PubMed2005

Characteristics of submucosal gastric carcinoma with lymph node metastatic disease.

AIM: To study the correlation between lymph node metastatic disease and various pathological parameters. Lymph node metastasis is the most important factor in determining the prognosis of patients with early gastric cancer and is significantly associated with the submucosal invasion of neoplastic cells. However, the depth of submucosal layer as well as the depth of submucosal tumour invasion varies among different cases. METHODS AND RESULTS: We studied various pathological parameters including the macroscopic appearance, location, size, area, differentiation, invasion depth, vascularity and fibrosis of submucosal gastric carcinomas (SMGC), using 248 age- and sex-matched tissue samples. The presence of lymphatic emboli, a larger area, greater size, a non-flat gross type and an increased vascularity of the tumour were significantly associated with node-positive SMGC. Among the three depth-related parameters, the ocular scale measurement, the sm3 method and the sm2 method, only the ocular scale measurement showed a significant correlation with node-positive SMGC. Using multivariate analysis, the incidence of lymph node metastasis increased in the lymphatic tumour emboli and in the tumours that invaded more than half of the submucosal layer. CONCLUSIONS: These histological indicators seem to be a feasible and easy way to predict lymph node metastatic disease from limited surgery specimens. Pathologists should carefully investigate the lymphatic invasion of tumour cells and measure the invasion depth of the tumour.

Adult↗