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Biomedical subjects

C Kim

Publications and source records attributed to C Kim.

At least 199 records · Page 11Linked to original sources
PubMed1998

Temperature-induced momentum-dependent spectral weight transfer in Bi2Sr2CaCu2O8+delta

Angle-resolved photoemission data from the cuprate superconductor Bi2Sr2CaCu2O8+delta above and below the superconducting transition temperature Tc reveal momentum-dependent changes that extend up to an energy of about 0.3 electron volt, or 40kTc (where k is the Boltzmann constant). The data suggest an anomalous transfer of spectral weight from one momentum to another, involving a sizable momentum transfer Q approximately (0.45pi, 0). The observed Q is intriguingly near the charge-order periodicity required if fluctuating charge stripes are present.

Journal Article↗
PubMed1998

Immunological analysis of methamphetamine antibody and its use for the detection of methamphetamine by capillary electrophoresis with laser-induced fluorescence.

An accurate, simple and rapid immunoassay is demonstrated for the detection of methamphetamine in urine by capillary electrophoresis (CE) with laser-induced fluorescence (LIF). An aminobutyl derivative of methamphetamine was conjugated with proteins, and used as an immunogen to produce antibodies for the assay. The methamphetamine derivative was also labeled with fluorescein isothiocyanate (FITC) to compete with free methamphetamine in the sample for the antibody binding site. Levels of free and antibody-bound FITC-labeled methamphetamine were monitored by performing CE-LIF using an untreated fused-silica column. This competitive immunoassay used antiserum instead of purified antibody or antibody fragment, yet was found to have good precision with a sensitivity of lower than 20 ng/ml. Various antibodies were also screened, and cross-reactivity of anti-MA antibody with methamphetamine analogues were also investigated. The results indicate that CE-LIF-based immunoassay is a powerful tool for the screening and characterization of antibody and may have possible applications in the detection of abused drugs in urine.

Animals↗
PubMed1998

Comparison of capillary electrophoresis-based immunoassay with fluorescence polarization immunoassay for the immunodetermination of methamphetamine using various methamphetamine antibodies.

An accurate and simple immunoassay using capillary electrophoresis (CE) with laser-induced fluorescence (LIF) was performed for the detection of methamphetamine (MA) in urine. The CE-LIF was conducted with an untreated fused-silica column using antiserum and a tracer of fluorescein isothiocyanate (FITC)-labeled MA. This CE-LIF system was compared with fluorescence polarization immunoassay (FPIA) in a TDx analyzer in the photo-check mode using the same FITC-labeled tracer and the same antiserum. Various antibodies, not only those prepared by our own immunogens but also those from commercial sources, were screened and characterized in both assay systems with regard to sensitivity, precision, and cross-reactivity. Both systems satisfied analytical precision and gave similar cross-reactivity patterns. However, the CE-LIF-based immunoassay was approximately one order superior to FPIA in sensitivity, requiring less volume of sample, antiserum, and tracer for the assay. Considering that the FPIA system is well known to be a useful tool for screening antibodies and detecting drugs, the CE-LIF-based immunoassay system, which is seemingly more advantageous than the FPIA system, appears to have great power for the characterization of antibodies and for the detection of MA in urine.

Antibodies↗
PubMed1998

Thermotolerance inhibits various stress-induced apoptosis in NIH3T3 cells.

When NIH3T3 cells were exposed to mild heat and recovered at 37 degrees C for various time intervals, they were thermotolerant and resistant to subsequent stresses including heat, oxidative stresses, and antitumor drug methotrexate which are apoptotic inducers. The induction kinetics of apoptosis by stresses were determined by DNA fragmentation and protein synthesis using [35S]methionine pulse labeling. We investigated the hypothesis that thermotolerant cells were resistant to apoptotic cell death compared to control cells when both cells were exposed to various stresses inducing apoptosis. The cellular changes in thermotolerant cells were examined to determine which components are involved in this resistance. At first, the degree of resistance correlates with the extent of heat shock protein synthesis which were varied depending on the heating times at 45 degrees C and recovery times at 37 degrees C after heat shock. Secondly, membrane permeability change was observed in thermotolerant cells. When cells prelabeled with [3H]thymidine were exposed to various amounts of heat and recovered at 37 degrees C for 1/2 to 24 h, the permeability of cytosolic [3H]thymidine in thermotolerant cells was 4 fold higher than that in control cells. Thirdly, the protein synthesis rates in thermotolerant and control cells were measured after exposing the cells to the same extent of stress. It turned out that thermotolerant cells were less damaged to same amount of stress than control cells, although the recovery rates are very similar to each other. These results demonstrate that an increase of heat shock proteins and membrane changes in thermotolerant cells may protect the cells from the stresses and increase the resistance to apoptotic cell death, even though the exact mechanism should be further studied.

3T3 Cells↗
PubMed1998

In vitro induction of HLA-A2402-restricted and carcinoembryonic-antigen-specific cytotoxic T lymphocytes on fixed autologous peripheral blood cells.

HLA-A2402-restricted and carcinoembryonic-antigen(CEA)-specific cytotoxic T lymphocytes (CTL) were induced by culturing human peripheral blood mononuclear cells (PBMC) on formalin-fixed autologous adhesive PBMC that had been loaded with CEA-bound latex beads. The CTL killed the CEA-producing HLA-type matched cancer cells, but not the non-producers of CEA, at an effector/target ratio of 10 within 24 h. On the basis of available HLA-A24-binding peptides, we have also attempted to identify the epitope peptide recognized by the CTL. The peptide CEA652(9), TYACFVSNL, stimulated the CTL most strongly when pulsed on HLA-A2402-expressing target cells. The other nine peptides so far tested were also active, but less efficient in their effect on CTL. The CTL failed to kill target cells pulsed with the HLA-A2-binding CEA peptide, CAP-1. The CTL were also generated on the fixed adherent cells previously pulsed with the peptide CEA652(9). Cytotoxic activity of the CTL was inhibited by monoclonal antibodies against CD3, CD8, and MHC class I molecules. These results suggest that human autologous CTL will be inducible on the autologous fixed PBMC without use of the cultured target cancer cells if tumor antigenic protein is available.

Adenocarcinoma↗
PubMed1998

Long-term outcome of primary glaucoma triple procedure with adjunctive 5-fluorouracil.

PURPOSE: To evaluate the long-term effect of adjunctive subconjunctival 5-fluorouracil (5-FU) on the filtration outcome of primary glaucoma triple procedure (PGTP) in primary open-angle glaucoma (POAG) patients. METHODS: Seventy-four POAG patients were randomly assigned to PGTP alone (36 patients) or PGTP with adjunctive subconjunctival 5-FU (5.0 +/- 1.3 injections of 5 mg each, total of 24.8 mg) (38 patients). After surgery, the patients were examined at regular intervals for intraocular pressure (IOP), visual acuity, medical therapy requirements, and complications. Surgical success was defined as IOP < or = 20 mmHg on postoperative medication < or = 1 without additional glaucoma surgery. RESULTS: Over an average follow-up (+/- SD) of 45.3 +/- 25.0 months, both 5-FU and control groups maintained significant improvement of IOP control and visual acuity. However, there were no statistically significant differences between the 5-FU and control groups with respect to postoperative IOP, number of glaucoma medications, visual acuity outcome, and success rate overall or in selected patients with one or more of the risk factors for filtration failure. CONCLUSIONS: The use of low-dose subconjunctival 5-FU (mean dosage of 24.8 mg in 5.0 +/- 1.3 injections) as an adjunct did not significantly improve the long-term filtration outcome of PGTP in POAG patients.

Aged↗
PubMed1998

Outcomes of primary phakic trabeculectomies without versus with 0.5- to 1-minute versus 3- to 5-minute mitomycin C.

PURPOSE: To compare the intraocular pressure and hypotony outcomes of primary phakic trabeculectomies with no mitomycin C (MMC), shorter MMC, and longer MMC exposure. METHODS: We evaluated primary phakic trabeculectomies with no MMC (36 eyes of 36 patients), 0.5- to 1-minute MMC (50 eyes of 50 patients), and 3- to 5-minute MMC (38 eyes of 38 patients) at the concentration of 0.5 mg/ml. Successful trabeculectomy was defined as an intraocular pressure of 21 mm Hg or less without development of a marked visual acuity loss associated with prolonged hypotony (intraocular pressure < 6 mm Hg over 3 months) and without the need for additional surgery to control intraocular pressure or treat postoperative complications. RESULTS: The three groups were similar in demographics, preoperative intraocular pressure, and medical dependency. However, the incidence of hypotony during the postoperative periods of 3 to 12 months was significantly higher in the 3- to 5-minute MMC group (P < .05, chi-square test). Severe visual acuity loss associated with hypotony was also more frequently found in the 3- to 5-minute MMC group than in the 0.5- to 1-minute (P = .009, chi-square test) group or the control group (P = .014, chi-square test). In addition, the success probabilities were significantly different among the three groups (P = .001, Kaplan-Meier survival analysis with log-rank test) and were the highest in the 0.5- to 1-minute MMC group and the lowest in the 3- to 5-minute MMC group. CONCLUSION: Shorter application (0.5 to 1 minute) of MMC appears to be optimal for the successful outcome of primary phakic trabeculectomy compared with no MMC or longer application of MMC at a concentration of 0.5 mg/ml.

Aged↗
PubMed1998

Limbus-based vs fornix-based conjunctival flap in combined glaucoma and cataract surgery with adjunctive mitomycin C.

PURPOSE: To determine the efficacy and safety of limbus-based vs fornix-based conjunctival flaps in patients with primary open-angle glaucoma undergoing trabeculectomy combined with phacoemulsification and intraocular lens implantation with adjunctive subconjunctival mitomycin C. METHODS: In a prospective study, 69 eyes of 69 patients with primary open-angle glaucoma, visually symptomatic cataracts, and no previous incisional ocular surgery were randomly assigned to limbus-based and fornix-based conjunctival flap groups. All patients received trabeculectomy combined with phacoemulsification and posterior chamber lens implantation with 1-minute (0.5 mg/ ml) application of subconjunctival mitomycin C. RESULTS: The mean intraocular pressures were significantly (P < .05) lower on significantly (P < .05) fewer medications postoperatively at 1 week, 1 month, 3, 6, 9, 12, and 15 to 18 months, and at last follow-up in both groups than they had been preoperatively. However, there were no significant (P > .05) differences in postoperative mean intraocular pressure, mean number of medications, and visual acuity between the two groups at any time interval. Hypotony with wound leak was significantly (P = .019) higher in the limbus-based group. Other postoperative complications were not significantly (P > .05) different between the two groups. CONCLUSIONS: There was no notable difference in glaucoma control or visual outcome between limbus-based and fornix-based conjunctival flaps in primary trabeculectomy combined with phacoemulsification and lens implantation with adjunctive subconjunctival mitomycin C. The fornix-based flap was as safe as, if not safer than, the limbus-based flap in the glaucoma triple procedure with adjunctive subconjunctival mitomycin C.

Aged↗
PubMed1998

Primary glaucoma triple procedure in patients with primary open-angle glaucoma: the effect of mitomycin C in patients with and without prognostic factors for filtration failure.

PURPOSE: To investigate the effect of adjunctive mitomycin C on primary glaucoma triple procedure in patients with primary open-angle glaucoma with and without one or more of the prognostic factors for filtration failure of primary glaucoma triple procedure. Those factors include being of African-American race, having a preoperative intraocular pressure of 20 mm Hg or more on maximum tolerated medications, and being on two or more medications preoperatively. METHODS: Study patients consisted of 197 consecutive patients with primary open-angle glaucoma who were randomly assigned to receive either no adjunctive mitomycin C (101 eyes of 101 patients) or to receive adjunctive subconjunctival mitomycin C (96 eyes of 96 patients) during the primary glaucoma triple procedure. Kaplan-Meier survival analysis comparisons were made between respective subgroups with and without prognostic indicators for filtration failures using a relatively stringent set of criteria for filtration success of primary glaucoma triple procedure. RESULTS: There was no statistically significant (P = .117) difference in filtration success of primary glaucoma triple procedure between the control and mitomycin C groups. Adjunctive mitomycin C significantly (P < .05) improved the filtration outcome of the primary glaucoma triple procedure in the subgroups with each of the three prognostic factors for filtration failure of primary glaucoma triple procedure. On the other hand, in the subgroups without the prognostic factors, adjunctive mitomycin C did not significantly (P > .05) change the filtration outcome of the primary glaucoma triple procedure. CONCLUSION: These findings establish the basis for selective use of mitomycin C in patients with primary open-angle glaucoma undergoing primary glaucoma triple procedure.

Aged↗
PubMed1998

The role of adjunctive mitomycin C in secondary glaucoma triple procedure as compared to primary glaucoma triple procedure.

OBJECTIVE: This study aimed to investigate whether previously failed glaucoma filtration surgery is a risk factor for filtration failure of subsequent trabeculectomy combined with cataract surgery and to determine the role of adjunctive mitomycin C (MMC) in the secondary glaucoma triple procedure (SGTP) as compared to primary glaucoma triple procedure (PGTP). DESIGN: A prospective, controlled study that was randomized with respect to assignment to adjunctive MMC and a case-control design with respect to comparisons between SGTP and PGTP was studied. PARTICIPANTS: The SGTP group consisted of 49 eyes of 49 consecutive patients with primary open-angle glaucoma with a history of glaucoma filtration surgery requiring glaucoma medical therapy and in need of cataract surgery, randomized to adjunctive MMC (SGTP MMC subgroup of 21 eyes) and no adjunctive MMC (SGTP control subgroup of 28 eyes). The PGTP group consisted of 49 PGTP cases closely matched to the SGTP cases with respect to age, race, gender, MMC use, C:D ratio, and systemic diseases. INTERVENTION: Trabeculectomy combined with phacoemulsification and a small incision (5 x 6 mm), all polymethylmethacrylate posterior chamber intraocular lens implantation with or without adjunctive MMC (0.5 mg/ml for 1 minute), was performed. MAIN OUTCOME MEASURES: Surgery failure was defined as the need of an additional intraocular procedure or the need of more than one medication to achieve intraocular pressure control to the target level. Intragroup and intergroup comparisons were made with respect to filtration outcome among the SGTP and PGTP patients. RESULTS: Without adjunctive MMC, filtration success was significantly less in SGTP than in PGTP (P = 0.03). Adjunctive MMC significantly increased the success rate of SGTP (P = 0.02) but not that of PGTP (P = 0.89) over the average follow-up period of 2 years. CONCLUSIONS: Previously failed glaucoma filtration surgery is a significant risk factor for the filtration failure of combined surgery. Intraoperative use of adjunctive MMC significantly improves the filtration success rate of SGTP.

Adult↗
PubMed1998

Decrease of capsular opacification with adjunctive mitomycin C in combined glaucoma and cataract surgery.

OBJECTIVE: The authors investigated the incidence of capsular opacification requiring YAG capsulotomy after primary trabeculectomy combined with phacoemulsification and implantation of all polymethylmethacrylate intraocular lenses. DESIGN: A prospective randomized study. PARTICIPANTS: One hundred seventy-four eyes of 174 nonselected patients with primary open-angle glaucoma (POAG) were randomized to either no adjunctive mitomycin C (MMC) control group of 93 eyes of 93 patients) or adjunctive subconjunctival MMC (MMC group of 81 eyes of 81 patients) during the primary glaucoma triple procedure (PGTP). INTERVENTION: Primary glaucoma triple procedure with and without MMC and YAG laser capsulotomy for posterior capsular opacification (PCO) was performed. MAIN OUTCOME MEASURES: The incidences of YAG capsulotomy for PCO were compared between the control and MMC groups and also between the control group and the MMC subgroups (1 minute, 3 minutes, and 5 minutes of MMC application) using Kaplan-Meier analysis with Mantel-Cox log-rank test. Cox proportional hazard regression analysis also was performed to identify significant factors affecting capsular opacification. RESULTS: The control and MMC groups were similar in preoperative characteristics. However, the probability of PCO requiring YAG capsulotomy was significantly lower in the MMC group than in the control group (P = 0.004). Among the MMC subgroups, MMC application for 3 minutes was most effective and significant when compared with that of the control group (P = 0.002). Although not as significant as the intraoperative use of MMC (P = 0.002), old age (P = 0.026) and presence of diabetes mellitus (P = 0.035) were also identified as significant beneficial factors for decreasing the incidence of YAG capsulotomy for PCO in Cox proportional hazard regression analysis. CONCLUSION: Intraoperative subconjunctival MMC application during combined glaucoma and cataract surgery has a beneficial effect of inhibiting PCO after combined surgery in patients with POAG. Thus, after intraoperative subconjunctival application of MMC at the concentration of 0.5 mg/ml for 3 minutes, the aqueous MMC level must have been great enough to inhibit the lens epithelial cell proliferation to result in a long-term decrease in PCO.

Aged↗
PubMed1998

Individual growth in Class III malocclusions and its relationship to the chin cap effects.

Individual growth characteristics of the maxilla and the mandible in Class III malocclusions were investigated in terms of growth amount, growth direction, and timing of growth; chin cap effects were considered in the context of growth characteristics of the jaws. Longitudinal cephalograms of six untreated Japanese Class III subjects were used for the analysis of jaw growth from 8 to 14 years of age. The facial patterns were classified into the five groups with different effects of therapy by discriminant functions derived from our previous chin cap study. The results obtained were as follows: (1) Among the six subjects, inhibition of maxillary forward growth was found in four subjects at ages before the maximum pubertal growth in body height occurred, resulting from occlusal interference of anterior cross bite. The growth potential of the jaws appeared genetically normal, and the facial patterns were classified into groups in which chin caps have been found to be effective to some extent. (2) A subject with growth characteristics of strong mandibular downward growth was classified in a group showing backward growth of the mandible by chin caps. (3) One of the remaining sample showing the strongest mandibular forward growth was classified in a group where chin caps are not effective. (4) It was concluded that effects of chin cap therapy are closely related to growth characteristics of the mandible in Class III treatment.

Adolescent↗
PubMed1998

Vasopressin and bradykinin regulate secretory processing of the amyloid protein precursor of Alzheimer's disease.

The amyloid protein precursor (APP) can be processed via several alternative processing pathways. Alpha-secretase processing by cleavage within the amyloid beta-peptide domain of APP is highly regulated by several external and internal signals including G protein-coupled receptors, protein kinase C and phospholipase A2. In order to demonstrate that G protein-coupled neuropeptide receptors for bradykinin and vasopressin can increase alpha-secretase processing of APP, we stimulated endogenously expressed bradykinin or vasopressin receptors in cell culture with the neuropeptides and measured the secreted ectodomain (APPs) in the conditioned media. Both bradykinin and vasopressin rapidly increased phosphatidylinositol (PI) turnover in PC-12 and in NRK-49F cells, indicating that these cell lines constitutively expressed functional PI-linked receptors for these neuropeptides. Both bradykinin and vasopressin readily stimulated APPs secretion. Increased APPs secretion was concentration-dependent and saturable, and it was blocked by receptor antagonists indicating specific receptor interaction of the peptides. The bradykinin-induced increase in APPs secretion in PC-12 cells was mediated by protein kinase C (PKC), whereas vasopressin receptors in NRK-49F cells were coupled to APP processing by PKC-independent signalling pathways. Our data show that neuropeptides can modulate APP processing in cell culture. In as much as increased alpha-secretase processing is associated with decreased formation of A beta(1-40), a major constituent of amyloid plaques, our findings suggest a possible role for modulating neuropeptide receptors as a strategy for altering amyloid metabolism in Alzheimer's disease brain.

Alzheimer Disease↗
PubMed1998

Risk assessment of cadmium exposure in Fort Resolution, Northwest Territories, Canada.

The aim of this study is to investigate the cadmium (Cd) exposure level from traditional food in Fort Resolution, Northwest Territories. We used 24-h dietary recalls and traditional food use frequency to obtain information on traditional food consumption, and analysed cadmium concentrations in traditional food. We also estimated total cadmium intake via market and traditional food, and cigarette smoking. Traditional food accounted for only 10% of the dietary energy. About 30 species of wildlife and plants were used. The most important foods in the community were moose, caribou, and whitefish. The range of cadmium concentrations measured was 0 to 1869 micrograms/g wet weight, with the lowest found in cranberry, and the highest in moose kidney. Cadmium concentrations in traditional food groups were comparable with those of Canadian market food. Highest levels of cadmium were found in the liver and kidney of caribou and moose. Cadmium intakes from traditional food estimated by dietary recall ranged from 0.01 to 1713 micrograms/g/day/person. Average cadmium intakes for women and men from traditional food were estimated to be 9% and 6% respectively, of the Provisional Tolerable Weekly Intake (PTWI, 400-500 micrograms) established by the World Health Organization. The average cadmium inhaled from cigarette smoking was 2.31 +/- 1.00 micrograms/day/person. There was no difference between the total cadmium intakes of smokers and nonsmokers. The total cadmium intake via market and traditional food and cigarette smoking was 136.6 micrograms/ week, which was lower than the PTWI. However, about 20% of the population may consume caribou and moose organ more frequently than the others. The potential health effects on this sub-population needs further clarification.

Animals↗
PubMed1998

Anti-human immunodeficiency virus activity and cellular metabolism of a potential prodrug of the acyclic nucleoside phosphonate 9-R-(2-phosphonomethoxypropyl)adenine (PMPA), Bis(isopropyloxymethylcarbonyl)PMPA.

Bis(isopropyloxymethylcarbonyl) 9-R-(2-phosphonomethoxypropyl)adenine [bis(POC)PMPA] has been identified as a novel prodrug of PMPA. The anti-human immunodeficiency virus activity of bis(POC)PMPA was >100-fold greater than that of PMPA in both an established T-cell line and primary peripheral blood lymphocytes. This improved efficacy was shown to be due to a rapid intracellular uptake of the prodrug resulting in an increased intracellular accumulation of PMPA diphosphate (PMPApp), the pharmacologically active metabolite. PMPApp levels in bis(POC)PMPA-treated cells exceeded by >1,000-fold the levels seen in cells treated with unmodified PMPA in both resting and activated peripheral blood lymphocytes. Significant differences in the intracellular catabolism of PMPA metabolites were noted between the resting and activated lymphocytes. The half-life for the disappearance of PMPApp, derived from either bis(POC)PMPA or PMPA, was 12 to 15 h in the activated lymphocytes and 33 to 50 h in the resting lymphocytes. This long persistence of PMPApp, particularly in resting lymphocytes, may be unique to the nucleoside phosphonate analogs and indicates that effective levels of the active metabolite can be achieved and maintained with relatively infrequent administration of the parent drug.

Adenine↗