Biomedical subjects

D S Kim

Publications and source records attributed to D S Kim.

At least 73 records · Page 4Linked to original sources

PubMed2001

Development of C-20 modified betulinic acid derivatives as antitumor agents.

Chemical modifications were performed on C-20 position of betulinic acid for a structure-activity relationship study. The evaluation of the compounds using human colon carcinoma HCT-116, human prostate adenocarcinoma PC3, and human melanoma cell lines M14-MEL, SK-MEL-2, and UACC-257 did not show any selective cytotoxicity towards melanoma cells. The results from both MTT reduction assay and SRB staining assay were comparable that no remarkable differences in cytotoxicity profile of the compounds were noticed. The C-20 position was found to be sensitive to the size and the electron density of the substituents in retaining the cytotoxicity of betulinic acid and was found to be undesirable position to derivatize.

Adenocarcinoma↗

PubMed2001

Fuc-TVII is required for T helper 1 and T cytotoxic 1 lymphocyte selectin ligand expression and recruitment in inflammation, and together with Fuc-TIV regulates naive T cell trafficking to lymph nodes.

To determine how the alpha(1,3)fucosyltransferases Fuc-TIV and Fuc-TVII, and the selectin ligands they control may contribute to the adaptive immune response, contact hypersensitivity (CHS) was characterized in mice deficient in either or both enzymes. We find a substantial CHS deficiency in Fuc-TVII(-/-) mice, and a complete deficiency in Fuc-TIV(-/-)/Fuc-TVII(-/-) mice. These defects are not accounted for by alterations in the number or function of epidermal Langerhans cells required for cutaneous antigen processing and presentation. By contrast, defective CHS in Fuc-TVII(-/-) mice or Fuc-TIV(-/-)/Fuc-TVII(-/-) mice is attributed in part to prominent, or nearly complete deficiencies, respectively, in the complement of naive T lymphocytes available in lymph nodes for antigen-dependent activation, expansion, differentiation, and dissemination. Fuc-TVII deficiency also deletes expression of E- and P-selectin ligands by Th1 and T cytotoxic 1 (Tc1) lymphocytes, annuls T cell trafficking to inflamed cutaneous sites in vivo, and thereby controls an essential component of the efferent phase of the cutaneous immune response. These observations indicate that collaborative contributions of Fuc-TIV and Fuc-TVII to L-selectin ligand synthesis, and to lymphocyte recruitment, are requisite components of the primary cellular immune response, and assign an essential role to Fuc-TVII in control of E- and P-selectin ligand expression by Th1 and Tc1 lymphocytes.

Animals↗

PubMed2001

Localized cerebral blood flow response at submillimeter columnar resolution.

Functional magnetic resonance imaging (fMRI) has been widely used for imaging brain functions. However, the extent of the fMRI hemodynamic response around the active sites, at submillimeter resolution, remains poorly understood and controversial. With the use of perfusion-based fMRI, we evaluated the hemodynamic response in the cat visual cortex after orientation-specific stimuli. Activation maps obtained by using cerebral blood flow fMRI measurements were predominantly devoid of large draining vein contamination and reproducible at columnar resolution. Stimulus-specific cerebral blood flow responses were spatially localized to individual cortical columns, and columnar layouts were resolved. The periodic spacing of orientation columnar structures was estimated to be 1.1 +/- 0.2 mm (n = 14 orientations, five animals), consistent with previous findings. The estimated cerebral blood flow response at full width at half-maximum was 470 microm under single-stimulus conditions without differential subtraction. These results suggest that hemodynamic-based fMRI can indeed be used to map individual functional columns if large-vessel contributions can be minimized or eliminated.

Animals↗

PubMed2001

Production of granular activated carbon from waste walnut shell and its adsorption characteristics for Cu(2+) ion.

Production of granular activated carbon by chemical activation has been attempted employing walnut shells as the raw material. The thermal characteristics of walnut shell were investigated by TG/DTA and the adsorption capacity of the produced activated carbon was evaluated using the titration method. As the activation temperature increased, the iodine value increased. However, a temperature higher than 400 degrees C resulted in a thermal degradation, which was substantiated by scanning electron microscopy (SEM) analysis, and the adsorption capacity decreased. Activation longer than 1h at 375 degrees C resulted in the destruction of the microporous structure of activated carbon. The iodine value increased with the increase in the concentration of ZnCl2 solution. However, excessive ZnCl2 in the solution decreased the iodine value. The extent of activation by ZnCl2 was compared with that by CaCl2 activation. Enhanced activation was achieved when walnut shell was activated by ZnCl2. Applicability of the activated carbon as adsorbent was examined for synthetic copper wastewater. Adsorption of copper ion followed the Freundlich model. Thermodynamic aspects of adsorption have been discussed based on experimental results. The adsorption capacity of the produced activated carbon met the conditions for commercialization and was found to be superior to that made from coconut shell.

Adsorption↗

PubMed2001

Differential usage of multiple brain-derived neurotrophic factor promoter in rat dorsal root ganglia following peripheral nerve injuries and inflammation.

The brain-derived neurotrophic factor (BDNF) may act as either an autocrine or paracrine survival factor for the dorsal root ganglion (DRG) neurons and may also serve as a neurotransmitter or neuromodulator within the dorsal horn of the spinal cord. The rat BDNF gene consists of four short 5' exons linked to separate promoters and one 3' exon encoding the mature BDNF protein. An exon-specific reverse transcription-polymerase chain reaction analysis was used to study the differential utilization of multiple promoters in the DRG following unilateral sciatic axotomy, dorsal rhizotomy and peripheral inflammation. The exon I transcript showed the highest induction rate with the ipsilateral expression elevated 4.3-5.8 times that of contralateral expression. Both exon II and III mRNAs showed a smaller increase 1 day after the three kinds of stimuli. In addition, exon IV mRNA transcription increased slightly only after rhizotomy, but not after axotomy and peripheral inflammation after 1 day. Furthermore, the elevated exon I mRNA levels 1 day after rhizotomy were sustained for up to 7 days. In contrast, those of the exon I mRNA after axotomy had declined 2.8 times the control level after 7 days. These findings suggest that the promoter linked to exon I may provide a major regulatory point of BDNF mRNA expression by peripheral nerve injuries and inflammation. In addition, both exon I and IV mRNA expression may show different temporal activation patterns according to the types of injury.

Animals↗

PubMed2001

Studies on the interfacial characterization of O/W emulsion for the optimization of its treatment.

Wastewater produced in the form of an o/w emulsion is difficult to treat properly because of its complex behavior. To acquire information for the optimization of emulsion controlling processes, the interfacial features of emulsion systems have been investigated in this work. The surface tension is found to decrease as the oil content is increased, and contact angle is influenced by the hydrophobicity of the substrate. The work of adhesion for substrates with different degrees of hydrophobicity has been estimated from the contact angle and surface tension. Temperature and pH have a significant influence on the turbidity and surface tension, and it is observed that electrophoretic characteristics of oil droplets are closely related with turbidity. Also, effects of inorganic salts and surfactants on the electrokinetic properties of emulsions have been considered, and the influence of coagulant on the stability is discussed through the calculation of potential energy of interaction between oil droplets. Adsorption and electrocoagulation processes have been attempted under various conditions in order to examine the practical treatment efficiencies of emulsion in relation to its interfacial characteristics.

Adsorption↗

PubMed2001

Large-fiber neuropathy in distal sensory neuropathy with normal routine nerve conduction.

Near-nerve needle sensory nerve conduction of plantar nerves in 100 patients with distal sensory neuropathy with normal routine nerve conduction (DSN-NNC) found the definite neuropathy pattern (abnormality in more than three of six tested nerves) in 65%, axonal neuropathy in 35%, and the known cause in 37% of patients. Absent or diminished reflexes were a reliable indicator for large fiber neuropathy (LFN). This near-nerve needle plantar nerve study provides useful and unequivocal evidence of its value in identifying neuropathy in DSN-NNC by finding LFN in 65% of patients.

Action Potentials↗

PubMed2001

The neuron restrictive silencer factor can act as an activator for dynamin I gene promoter activity in neuronal cells.

The neuron restrictive silencer element (NRSE) has been identified in several neuronal genes and confers neuron specificity by silencing transcription in nonneuronal cells. We have previously reported that Sp1 and an NF-kappaB-like element (NE-1) are required for the promoter activity of mouse dynamin I gene. In the present study, we found that the upstream regulatory region of the dynamin I promoter has an NRSE-like sequence and showed that neuron restrictive silencer factor (NRSF) binds to this element in neuronal cells as well as in nonneuronal cells. We also showed that NRSF activates the promoter activity of dynamin I gene in neuronal cells. From the results in this study, we suggest that NRSE might be involved in the neuron restriction of dynamin I expression, and NRSF could act as an activator for promoter activity of dynamin I gene in neuronal cells.

Animals↗

PubMed2001

Curcuminoids from Curcuma longa L. (Zingiberaceae) that protect PC12 rat pheochromocytoma and normal human umbilical vein endothelial cells from betaA(1-42) insult.

beta-Amyloid (betaA) induced oxidative stress is a well-established pathway of neuronal cell death in Alzheimer's disease. From turmeric, Curcuma longa L. (Zingiberaceae), three curcuminoids, curcumin, demethoxycurcumin, and bisdemethoxycurcumin, were found to protect PC12 rat pheochromocytoma and normal human umbilical vein endothelial (HUVEC) cells from betaA(1-42) insult, as measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide reduction assay. ED(50) values of curcumin, demethoxycurcumin, and bisdemethoxycurcumin toward PC12 and HUVEC cells were 7.1+/-0.3, 4.7+/-0.1, 3.5+/-0.2 microg/ml and 6.8+/-0.4, 4.2+/-0.3, and 3.0+/-0.3 microg/ml, respectively. These compounds were better antioxidants than alpha-tocopherol as determined by DPPH radical trapping experiment. alpha-Tocopherol did not protect the cells from betaA(1-42) insult even at>50 microg/ml concentration. The results suggest that these compounds may be protecting the cells from betaA(1-42) insult through antioxidant pathway.

Alzheimer Disease↗

PubMed2001

Vascular effects of synthetic or natural progestagen combined with conjugated equine estrogen in healthy postmenopausal women.

BACKGROUND: Synthetic, not natural, progestagen may negate the favorable effects of estrogen. Nonetheless, observational studies report no differences in risk for clinical cardiovascular events between users of unopposed estrogen and users of estrogen combined with synthetic progestin. METHODS AND RESULTS: In a double-blind study, we randomly assigned 20 healthy postmenopausal women to micronized progesterone (MP) 200 mg or medroxyprogesterone acetate (MPA) 10 mg for 10 days with conjugated equine estrogen (CEE) 0.625 mg for 25 days and the remaining 5 days off cyclically during 2 months, followed by crossover to the alternate therapy. CEE+MP and CEE+MPA significantly improved the percent flow-mediated dilator response to hyperemia relative to baseline measurements (P=0.004 by ANOVA) by a similar degree (P=0.863). Both therapies significantly decreased E-selectin, intercellular adhesion molecule (ICAM)-1, and vascular cell adhesion molecule (VCAM)-1 levels from baseline values (P<0.001, P=0.048, and P=0.016 by ANOVA, respectively) by a similar degree (P=0.977 for ICAM-1 and P=0.541 for VCAM-1, respectively). CEE+MPA decreased E-selectin levels more than CEE+MP did (P=0.040). Both therapies significantly decreased monocyte chemoattractant protein-1 levels from baseline values (P<0.005 by ANOVA) by a similar degree (P=0.194). Both therapies significantly decreased tissue factor antigen and increased tissue factor activity levels from baseline values (P=0.003 and P<0.001 by ANOVA, respectively) by a similar degree (P=0.652 for antigen and P=0.173 for activity). Both therapies significantly lowered plasma plasminogen activator inhibitor-1 levels from baseline values (P<0.001 by ANOVA) by a similar degree (P=0.533). CONCLUSIONS: CEE+MP and CEE+MPA provide similar improvement in endothelium-dependent vasodilator responsiveness and effects on markers of inflammation, hemostasis, and fibrinolysis inhibition in healthy postmenopausal women.

Chemokine CCL2↗

PubMed2001

Mechanisms for the generation of coherent longitudinal-optical phonons in GaAs /AlGaAs multiple quantum wells.

We show that coherent optical phonons in GaAs multiple quantum wells are generated in a completely different way as compared to bulk GaAs. Unlike in bulk GaAs where the ultrafast screening of electric fields by photogenerated charge carriers is known to be dominant, three distinctive generation mechanisms contribute simultaneously in multiple quantum wells. The interplay between impulsive Raman scattering, forbidden Raman scattering, and screening of surface electric fields, whose relative strengths are determined by laser intensity, detuning from the exciton resonance, and the barrier width, generates a rich variety of new phenomena.

Journal Article↗

PubMed2001

Aberrant expression of cyclin D1 is associated with poor prognosis in early stage cervical cancer of the uterus.

OBJECTIVE: Many investigators have studied the expression of G1 phase regulatory protein in uterine cervical cancer. However, it is unclear which step of the genetic expression participates in cyclin D1 expression and what its prognostic meaning is. The aims of this study were to evaluate the regulatory level of cyclin D1 expression and the relationship between the expression of cyclin D1 and its inhibitor, p21WAF1/CIP1, and to evaluate their impact on the prognosis of early stage cervical cancer. METHODS: The presence of cyclin D1 mRNA was studied using Northern blot in 6 normal cervices and 7 invasive cervical cancer specimens. Western blot was used to detect the cyclin D1 protein in 8 normal cervices and 8 invasive cancer specimens. Thirty-two cases of FIGO stage Ib-IIa cervical cancers (28 squamous cell carcinomas, 3 adenocarcinomas, 1 adenosquamous cell carcinoma), 31 cases of cervical intraepithelial neoplasia 3 (CIN 3), and 28 normal cervices were stained for cyclin D1 and p21(WAF1/CIP1) using monoclonal antibody. Statistical analysis was performed to assess the differences in expression and their prognostic significance. RESULTS. Cyclin D1 mRNA was found to be underexpressed in cervical cancer. Western blot also revealed underexpression of cyclin D1 protein in cervical cancer compared to normal controls. Positive immunohistochemical staining of cyclin D1 was noted in 28/28 (100%) of the normal controls, 1/31 (3%) cases of CIN 3, and 9/32 (28%) cases of invasive cancer. The number of positively stained specimens was lower than that of normal controls in CIN 3 and cervical cancer specimens (P = 0.005). Fifteen of 28 (54%) normal controls, 15/31 cases (48%) of CIN 3, and 27/32 cases (84%) of invasive cancer were proved positive for p21WAF1/CIP1 immunohistochemistry. p21WAF1/CIP1 was more highly expressed in cervical cancer than in that of either normal controls or CIN specimens (P = 0.001). Positive immunostaining of cyclin D1 and p21WAF1/CIP1 was not related to high-risk factors (pelvic lymph node metastasis, deep cervical stromal invasion, parametrial invasion, large tumor size, and unusual histologic type) and human papilloma virus infection. Positive cyclin D1 immunostaining was associated with decreased disease-free survival and a lower overall survival (P = 0.0175 and 0.0189, respectively). On multivariate analysis, positive cyclin D1 expression was a significant prognostic variable for recurrence (P = 0.0004). CONCLUSION: Underexpression of cyclin D1 was regulated at the level of transcription in cervical cancer. Although cyclin D1 was underexpressed in cervical neoplasias, it was more frequently expressed in malignant lesions. p21WAF1/CIP1 was more highly expressed in cervical cancers than in either normal cervices or CIN 3 specimens. Unfavorable prognoses were associated with cyclin D1 expression, and not with the expression of its inhibitor, p21WAF1/CIP1.We conclude that immunohistochemical assessment of cyclin D1 can be a useful molecular marker for predicting prognosis in early stage cervical cancer of the uterus.

Blotting, Northern↗

PubMed2001

Ten-year survival of patients with locally advanced, stage ib-iib cervical cancer after neoadjuvant chemotherapy and radical hysterectomy.

OBJECTIVE(S): The aim of this study was to evaluate the effects of neoadjuvant chemotherapy and radical hysterectomy on long-term survival in stage IB-IIB locally advanced cervical cancer by conducting a 10-year follow-up. METHODS: Between August 1983 and May 1990, 80 locally advanced, stage IB-IIB cervical cancer patients with tumor diameter greater than or equal to 4 cm were treated with neoadjuvant VBP chemotherapy (cisplatin, vinblastine, and bleomycin) followed by radical hysterectomy with pelvic lymphadenectomy. After this therapeutic modality, patients were followed for more than 10 years. Ten-year survival rates and factors affecting recurrence after this therapy were evaluated. RESULTS: Of 80 patients, 75 (93.7%) showed a reduction in tumor size after neoadjuvant chemotherapy. At pathologic examination, stage reduction was noted in 53 (66.2%) patients and 20 patients (25%) showed no residual or microinvasive cervical tumor. Pelvic lymph node metastases were found in 17 patients (21.3%). During the 10-year follow up, 2 patients were lost and 16 patients recurred. Overall 5-year and 10-year disease-free actual survival rates were 82.0 (64/78) and 79.4% (62/78), respectively. Clinical stage, initial tumor size, clinical response, and residual tumor size were not risk factors for recurrence after this therapy. However, pelvic lymph node metastasis was a significant risk factor for recurrence. CONCLUSION(S): Neoadjuvant VBP chemotherapy followed by radical hysterectomy in locally advanced, stage IB-IIB cervical cancer patients seemed to improve the long-term survival rate for these patients compared to that of conventional therapy. However, randomized controlled trials are needed to confirm this result.

Adenocarcinoma↗

PubMed2001

Allergenicity test of genetically modified soybean in Sprague Dawley rats.

Allergenicity of genetically-modified (GM) soybean was evaluated in male Sprague Dawley rats. To confirm the GM soybean used in this study, the polymerase chain reaction (PCR) was performed using the chromosomal DNA of soybeans. The PCR result provided the clear discrimination of genetically-modified (GM) soybeans. To evaluate the allergenicity of GM soybean and non-GM control one, the soybean homogenate was sensitized subcutaneously 3 times a week for 3 weeks. The doses of soybean were 0, 2 and 20 mg/kg in the protein basis. A week after the last sensitization, antisera were recovered from individual animals. When the sera were injected intradermally on the clipped back of unsensitized rats with various dilutions, followed by a challenge with 20 mg/kg of soybean homogenate containing 1% Evans blue, no sign of passive cutaneous anaphylaxis reaction was detected. In addition, when the sera were treated in the cultures of peritoneal mast cells, the increase of histamine release by anti-(GM soybean) sera was not observed when compared to that by anti-(non-GM soybean) sera. The present results indicate that the GM soybean might not act as a strong allergen in male Sprague Dawley rats.

Animals↗

PubMed2001

Comparison of the response to the prone position between pulmonary and extrapulmonary acute respiratory distress syndrome.

OBJECTIVES: To determine whether the response to the prone position differs between acute respiratory distress syndrome (ARDS) resulting from a pulmonary cause (ARDSp) and that from an extrapulmonary cause (ARD-Sexp). DESIGN AND SETTING: Prospective observational study in a medical ICU of a university-affiliated hospital. SUBJECTS: A consecutive series of 31 patients with ARDSp and 16 with ARDSexp within 3 days of onset of ARDS. INTERVENTION: Prone position for at least 2 h. MEASUREMENTS AND RESULTS: In ARDSp, compared with the supine position (121 +/- 49 mmHg), PaO2/FIO2 was not increased after 0.5 h but was increased after 2 h in the prone position (158 +/- 60 mmHg). In ARDSexp, compared with the supine position (106 +/- 53 mmHg), PaO2/FIO2 was increased after 0.5 h (155 +/- 91 mmHg), but was not further changed after 2 h. Marked oxygenation response (increase in PaO2/FIO2 > 40% from baseline) after 0.5 h was 23% in ARDSp and 63% in ARDSexp, and that after 2 h was 29% and 63%, respectively. Static respiratory compliance decreased in the prone position in ARDSexp (30 +/- 11 ml/cmH2O at baseline, 27 +/- 11 after 0.5 h and 25 +/- 9 after 2 h) but not in ARDSp. Consolidation score as determined on the first chest radiography taken in the prone position decreased to a greater degree in ARDSexp (-2.4 +/- 4.1) than in ARDSp (0.3 +/- 4.1). CONCLUSION: Pulmonary ARDS and extrapulmonary ARDS in their early stages respond differently to the prone position with regard to the time course of oxygenation, respiratory mechanical behaviour, and radiographic change. These findings suggest that the early pathophysiology of ARDS differs according to the type of primary insult to the lung.

Aged↗

PubMed2001

Selective posterior rhizotomy in children with cerebral palsy: a 10-year experience.

We reviewed our 10-year experience of selective posterior rhizotomy (SPR), with an emphasis on surgical outcome concentrated on improvements in functional ability and adverse effects. We had performed SPR in 208 patients between 1990 and 1999. All patients showed an overall improvement (over 95%) in spasticity, passive range of motion, and gait pattern. Preoperative ambulatory functional level and age were very important predictive factors for further improvements in postoperative functional ability. Compared with the younger children, the older ones lacked a full range of motion preoperatively, and they continued to lack a full range of motion postoperatively, despite the decrease in tone achieved by SPR. Most postoperative complications such as hypotonia, urinary retention, spinal deformities, and sensory changes were temporary and not functionally important. We conclude that SPR is an effective method of alleviating spasticity and provides lasting functional benefits at acceptable complication levels in spastic children with cerebral palsy.

Activities of Daily Living↗

PubMed2001

Biochemical characterization of a thrombin-like enzyme and a fibrinolytic serine protease from snake (Agkistrodon saxatilis) venom.

A thrombin-like enzyme and a fibrinolytic serine protease were purified to homogeneity from the venom of a Korean snake Agkistrodon saxatilis emelianov. Both the purified enzymes migrated as a single protein band corresponding to 39 kDa in SDS-PAGE. However, the molecular mass was reduced to 28 kDa by enzymatic removal of the N-linked carbohydrates in those two different enzyme species. Although the thrombin-like enzyme and the fibrinolytic protease show homologous features in their molecular sizes and N-terminal amino acid sequences, yet they can be clearly distinguished from each other in terms of substrate specificity, susceptibility to inhibitors and fibrinogen degradation. It is postulated that these two enzymes are capable of functioning in a cooperative manner to effectively remove fibrinogen and consequently to reduce the blood viscosity.

Amino Acid Sequence↗

PubMed2001

Crab shell for the removal of heavy metals from aqueous solution.

The ability of crab shell to remove heavy metals from aqueous solution was evaluated by comparing with that of several sorbents (cation exchange resin, zeolite, granular activated carbon, powdered activated carbon). All experiments were conducted using several heavy metal ion solutions (Pb, Cd, Cu, Cr). The orders of heavy metal removal capacity and initial heavy metal removal rate were found as crab shell > cation exchange resin > zeolite > powdered activated carbon>granular activated carbon. Therefore, crab shell is satisfactory as a good biosorbent for the heavy metal removal. The study indicates that the removal of these heavy metals is selective, with Pb and Cr being removed in preference to Cd and Cu. The sorption equilibrium of heavy metal ions on sorbents was modeled on the applications of Langmuir and Freundlich.

Adsorption↗