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D K Kim

Publications and source records attributed to D K Kim.

At least 271 records · Page 15Linked to original sources
PubMed1992

Immunochemical detection of arachidonoyl-preferential phospholipase A2.

Monoclonal antibodies were raised against rabbit platelet cytosolic arachidonoyl-preferential phospholipase A2. The antibodies precipitated the arachidonoyl-preferential phospholipase A2 activity in the soluble fraction of a rabbit platelet lysate in combination with an immobilized anti-mouse immunoglobulin antibody, and reacted predominantly with a protein exhibiting a molecular weight of approximately 88,000 on immunoblotting analysis. All three antibodies established so far reacted with human platelet arachidonoyl-preferential phospholipase A2 as effectively as the rabbit platelet enzyme. One of them reacted with the rat platelet arachidonoyl-preferential enzyme, whereas none of them reacted with rabbit platelet secretory 14-kDa group II phospholipase A2. The existence of an immunologically related phospholipase A2 was further shown in rabbit granulocytes, brain, lung, and liver, rat and mouse mast cells, and human monocytoma U937 cells. Thus, an arachidonoyl-preferential phospholipase A2 with similar structural properties appeared to be expressed in a variety of cells and tissues.

Animals↗
PubMed1992

Longitudinal monitoring for disease progression of localized juvenile periodontitis.

The present study was performed to investigate the factors associated with disease progression in localized juvenile periodontitis (LJP) patients by longitudinal monitoring of microbiological changes. Following a 9-month period, 9 LJP patients were divided into 2 groups based upon attachment loss, progressing and non-progressing. Both groups received scaling, root planing, and modified Widman flaps. Clinical and microbiological data were obtained at baseline, following the observation period, and at 6 and 12 months post-treatment. At 6 and 12 months post-treatment significantly more cocci were persistent in the non-progressing group than in the progressing group. Actinobacillus actinomycetemcomitans was also more frequently isolated in the progressing group than in the non-progressing group initially and following the 9-month observation period. Also after treatment, A. actinomycetemcomitans recolonized earlier in the progressing group than in the non-progressing group. These studies suggest that A. actinomycetemcomitans may play a role in disease progression in LJP; however, they do not eliminate the possibility that other organisms may also play a role, since A. actinomycetemcomitans was not detected in all of the patients in whom disease progressed.

Adolescent↗
PubMed1992

Fleroxacin clinical pharmacokinetics.

Fleroxacin is a new member of the class of fluoroquinolones. The drug has good activity (i.e. minimum inhibitory concentrations at less than 2 mg/L against 90% of strains) against a wide range of Gram-positive and Gram-negative bacteria. High performance liquid chromatography is used to determine concentrations of fleroxacin and its metabolites in biological fluids. Absorption of orally ingested drug is rapid as the peak plasma concentration of approximately 5 mg/L is reached in 1 to 2h after a single dose of 400mg. The systemic availability is close to 100%. Fleroxacin is poorly bound to plasma proteins (23%) and exhibits excellent tissue distribution. Renal clearance accounts for 60 to 70% of elimination. The drug is metabolised to form antimicrobially active N-demethyl-fleroxacin and inactive N-oxide-fleroxacin. In multiple dose studies the accumulation ratio of a once-daily dosage regimen is about 1.3, as predicted from the elimination half-life of 10 to 12h. Compared with ciprofloxacin, fleroxacin has a greater systemic availability and a longer half-life. Fleroxacin concentrations are higher in elderly patients, but further studies are needed to establish whether a dosage reduction should be recommended for this age group. In patients with renal disease dosage adjustment is recommended since a decreased renal clearance of fleroxacin leads to a significant prolongation of the elimination half-life. Fleroxacin is only poorly eliminated by peritoneal dialysis or haemodialysis. The most important drug-drug interaction is a decrease in systemic availability of fleroxacin after ingestion of aluminium- or magnesium-containing antacids. There is no evidence of a significant interaction between fleroxacin and theophylline. Only limited data are available on adverse reactions of fleroxacin. The most important adverse effects appear to be photosensitivity and a dose-dependent incidence of central nervous system reactions including sleep disorders.

Adult↗
PubMed1991

Purification and characterization of human platelet phospholipase A2 which preferentially hydrolyzes an arachidonoyl residue.

A phospholipase A2 with an arachidonoyl residue preference was purified about 11,700-fold from human platelet soluble fraction to near homogeneity. The purified phospholipase A2 exhibited a molecular mass of about 90 kDa on SDS polyacrylamide gel electrophoresis and hydrolyzed phospholipids with an arachidonoyl residue more effectively than those with a linoleoyl residue. The catalytic activity of the purified enzyme detected with phosphatidylcholine as a substrate increased sharply between 3 x 10(-7) and 10(-6) M free calcium ion. Thus, the 90-kDa phospholipase A2 is considered to be a novel enzyme, distinct from the 14-kDa one previously purified from human platelets. The 90-kDa phospholipase A2 may participate mainly in arachidonate metabolism of platelets.

Arachidonic Acid↗
PubMed1991

Purification and characterization of rabbit platelet cytosolic phospholipase A2.

A phospholipase A2 was purified from rabbit platelet cytosolic fraction to near homogeneity by sequential column chromatographies on heparin-Sepharose, DEAE-Sephacel, butyl-Toyopearl, DEAE-5PW ion-exchange HPLC, and TSK gel G3000SW gel-filtration HPLC. The final preparation with an estimated specific activity of 8630 nmol/min per mg protein, showed a single band with a molecular mass of about 88 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by silver staining. The 88-kDa phospholipase A2 exhibited a fatty acid preference; it hydrolyzed phospholipid bearing an arachidonoyl residue at the sn-2 position more effectively than that with a linoleoyl residue. The catalytic activity of the purified enzyme with phosphatidylcholine or phosphatidylethanolamine increased sharply in the presence of between 10(-7) and 10(-6) M calcium ion, indicating that it could be regulated by less than micromolar concentration of calcium. These characteristics differ from those of platelet secretory 14-kDa phospholipase A2 reported previously. Therefore, this 88-kDa enzyme is a novel phospholipase A2 and may participate in the stimulus-dependent release of arachidonoyl residues in rabbit platelets.

Animals↗
PubMed1991

Purification and some properties of a phospholipase A2 from bovine platelets.

An intracellular form of phospholipase A2 was purified about 47,500-fold to near homogeneity from bovine platelets 100,000 x g supernatant by sequential use of column chromatographies on Heparin-Sepharose, DEAE-Sephacel, Butyl-Toyopearl, Sephacryl S-300, DEAE-5PW HPLC, TSK G 3000 SW HPLC and Mono Q FPLC. The final preparation showed a single band on SDS-polyacrylamide gel, and its molecular mass was estimated to be approximately 100,000 daltons. The purified PLA2 showed maximal activity at alkaline pH(pH 9.0-10.0) and considerable activity at 0.3-1.0 microM calcium concentration. It hydrolyzed phosphatidylcholine containing arachidonate at sn-2 position with high selectivity in comparison to linoleate.

Animals↗
PubMed1991

Physical characteristics of Ti-6A1-4V implants fabricated by electrodischarge compaction.

Physical characteristics of a Ti-6A1-4V implant were evaluated following fabrication using a new electrodischarge compaction technique. Ti-6A1-4V atomized powders were loaded into Pyrex tubes (3.3 mm ID) and subjected to a high-voltage, high-current-density pulse in air for a period of less than 300 microseconds. Single pulses (1.0, 1.5, 2.0 and 2.5 KJ/grampowder) were applied from a capacitor bank (240, 480 or 720 microF) to produce solid core implants with porous surface layers. Implants were evaluated microscopically for core size, neck size, pore size, grain structure, and incorporated oxide film. Hardness was also evaluated. Implants were compared with Ti-6A1-4V commercial powders. Core size increased and pore size decreased with increases in energy and capacitance. The cores were composed of equiaxed grains which were free of oxide at the grain boundary. Porous layers, consisting of particles connected in three dimensions by necks, were free of oxide films at the connecting interfaces. Neck size increased with increases in input energy and capacitance. Hardness readings of the core, necks, and porous particles resulted in readings higher than or similar to control materials. Electrodischarge compaction did not alter the physical characteristics during compaction.

Alloys↗
PubMed1991

Effects of beta-hydroxybutyrate on oxidative metabolism and phosphorylation potential in canine heart in vivo.

beta-Hydroxy-butyrate (HBA) is an effective substrate for mitochondrial respiration (MVO2) in the heart. Myocardial HBA oxidation is associated with high mitochondrial NADH and an inhibition of glycolytic flux. The purpose of this study was to investigate if the infusion of HBA in vivo could modify the coupling mechanisms between myocardial MVO2 and work in the presence and absence of epinephrine. The extraction of several oxidized metabolites, O2, and HBA was measured during the infusion of HBA as well as the high-energy phosphate metabolites using 31P-nuclear magnetic resonance spectroscopy. HBA infusion did not affect the MVO2 or function of the heart with or without epinephrine infusion. However, HBA increased the phosphorylation potential by decreasing inorganic phosphate and the calculated free ADP concentration under both conditions. This is consistent with HBA increasing the mitochondrial NADH, which results in an increase in the phosphorylation potential without modifying function. These data demonstrate that substrates, specifically HBA, can modulate the cardiac phosphorylation potential in vivo. The most likely mechanism for this effect is through the mitochondrial NADH concentration.

3-Hydroxybutyric Acid↗
PubMed1990

Detection and subcellular localization of rabbit platelet phospholipase A2 which preferentially hydrolyzes an arachidonoyl residue.

Like rat platelets, rabbit platelets contain a secretory 14-kDa group II phospholipase A2 [Mizushima, H., Kudo, I., Horigome, K., Murakami, M., Hayakawa, M., Kim, D.K., Kondo, E., Tomita, M., & Inoue, K. (1989) J. Biochem. 105, 520-525]. The present study was undertaken to determine whether or not, in addition to that of the 14-kDa group II enzyme, rabbit platelets exhibit another phospholipase A2 activity. A rabbit platelet soluble fraction was prepared by sonication and centrifugation. When this soluble fraction was subjected to heparin-Sepharose column chromatography, phospholipase A2 activity was detected in both heparin-binding and heparin-non-binding fractions. The activity detected in the heparin-binding fraction appeared to belong to the secretory 14-kDa phospholipase A2, because it bound to anti-human 14-kDa group II phospholipase A2 monoclonal antibody. The activity found in the heparin-non-binding fraction did not appreciably react with the same antibody. When platelets were gently disrupted by the nitrogen cavitation method, the heparin-non-binding activity was mainly recovered in the platelet cytosolic fraction. The heparin-non-binding phospholipase A2 hydrolyzed a phospholipid bearing an arachidonoyl residue at the sn-2 position more effectively than one with a linoleoyl residue. The biochemical features of the activity observed in the heparin-non-binding fraction generally resembled those of human platelet soluble phospholipase A2 [Kim, D.K., Kudo, I., & Inoue, K. (1988) J. Biochem. 104, 492-494].(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Acetylcholine-activated ionic currents in parasympathetic neurons of bullfrog heart.

1. The electrical and pharmacologic properties of acetylcholine (ACh)-induced current (IACh) were studied in the parasympathetic neurons isolated from bullfrog heart with the use of the concentration-clamp technique, which allows intracellular perfusion and rapid change of external solution within 2 ms under the single-electrode voltage-clamp condition. 2. The IACh consisted of an initial transient peak component and a successive steady-state plateau component. Both currents increased in a sigmoidal fashion with increasing ACh concentration. The dissociation constant (Kd value) and the Hill coefficient for each component were 2.2 X 10(-5) M and 1.6, respectively. 3. In the K(+)-free solution, the reversal potential (EACh) of IACh was close to the Na+ equilibrium potential (ENa). The current-voltage (I-V) relation showed inward rectification at positive potentials. 4. Nicotine mimicked only the peak component of IACh. However both peak and steady-state components were blocked nonselectively by the nicotinic blockers d-tubocurarine and hexamethonium. 5. Carbamylcholine (CCh) mimicked the steady-state component of IACh. The steady-state component was selectively inhibited by atropine at concentrations 1,000 times lower than that required for inhibition of the peak component. The steady state was blocked equally by either pirenzepine (M1 blocker) or AF-DX-116 (M2 blocker). 6. It was concluded that the IACh consisted of a peak component having double exponential activation and inactivation, mediated through the nicotinic actions, and a steady-state component having no inactivation, mediated through the muscarinic action.

Acetylcholine↗
PubMed1990

Proton-gated sodium current in parasympathetic ganglion cells of frog heart.

1. The proton-gated current was investigated in whole-cell configuration of the neurons isolated from bullfrog heart parasympathetic ganglia with the use of the "concentration-clamp" technique, which combines intracellular perfusion and extremely rapid exchange of external solution within 1-2 ms, under a single-electrode voltage-clamp condition. 2. In all isolated neurons, a "step" decrease in extracellular pH (pHo) induced a transient inward current that was followed by a complete inactivation within 1 s. 3. The proton-gated current increased in a sigmoidal fashion as pHo decreased. In the external solution containing 2 mM Ca2+, the threshold of current activation was at pHo 7.4, and the maximum response appeared at pHo 6.5-5.5. The dissociation constant (Kd) and Hill coefficient were 7.1 and 3.2, respectively. 4. The proton-gated current was reduced by decreasing the extracellular Na+ concentration. In the absence of K+, the current produced by reduced extracellular pH reversed at the Na+ equilibrium potential (ENa), indicating that the current was carried by Na+. 5. Kinetics of both the activation and inactivation phases of proton-induced current were single exponential. The time constants of activation (tau a) and inactivation (tau i) had no potential dependence but decreased slightly by decreasing pHo. 6. In the inactivation curve of the proton-induced current obtained by decreasing pHo from various conditioning pHos to 6.5, the half-maximum inactivation occurred at pHo 7.75. 7. The proton-gated current was suppressed as the extracellular Ca2+ concentration [( Ca2+]o) increased from 0.1 to 10 mM, and the half inhibition occurred at greater than 10 mM [Ca2+]o.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

A nonparametric method for estimating interaction effect of age and period on mortality.

In this paper we introduce a new model and develop an estimation strategy to analyze mortality data. The model we dealt with has the specific structure E[log qij] = mu + alpha i + beta j + rho ij subject to the linear restrictions sigma i alpha i/sigma 2i = sigma j beta j = sigma i pij/sigma 2i = sigma j rho ij = 0 for any i and j; here, qij denotes the mortality for the jth period category and ith age category, mu denotes the overall mean, alpha i denotes the ith age effect in antichronological order, beta j the jth period effect, rho ij the general interaction effect; and sigma 2i is the common error variance of log qij for the ith age group. We propose a combined technique of ANOVA and nonparametric smoothing for estimating these parameters. The methods described are illustrated by mortality data on rectum cancer in Japanese males and females between 1950-1986.

Age Factors↗
PubMed1989

Protein kinase C-dependent and -independent mechanisms of cloned murine T cell proliferation. The role of protein kinase C translocation and protein kinase C activity.

PMA can induce the proliferation of several CTL clones but not of several Th clones derived and tested in our laboratory. The PMA-stimulated proliferation of our CTL clones (which do not make IL-2 mRNA or protein) occurs independently of IL-2 and is not accompanied by lymphokine release. We now report, however, that protein kinase C (PKC) translocation is induced by PMA in CTL clones as well as in Th clones, which lack a proliferative response to PMA. These results suggest that PKC translocation itself is not a sufficient regulatory mechanism to account for cloned T cell proliferation. Moreover, IL-2 did not induce PKC translocation in a CTL clone, which proliferates when stimulated with IL-2. Thus, PKC translocation may not be necessary for activation of CTL proliferation. Nonetheless, cellular PKC activity appears to be required for the proliferative response of T cell clones after stimulation by PMA/PMA + calcium ionophore (A23187) or by triggering through the TCR: chronic PMA treatment, which depletes intracellular PKC activity, abrogates the proliferative response of T cell clones stimulated by PMA/PMA + A23187 or triggered through the TCR. T cell clones depleted of PKC activity, however, retain the ability to proliferate when challenged with IL-2. Murine T cell clones, therefore, possess PKC-dependent and PKC-independent pathways of proliferation that are not regulated by PKC translocation alone.

Animals↗
PubMed1989

The poor statistical properties of the Fe-plot.

The poor statistical properties of the Fe-plot as a method of estimating the alpha/beta ratio in the linear quadratic model for multifraction data are summarized. A Monte Carlo simulation of quantal response data shows that the Fe-plot method of analysis is about half as efficient as logistic regression, indicating that twice the amount of data would be needed to obtain the same accuracy in the estimate of alpha/beta if the Fe-plot was used rather than logistic regression. In addition, the confidence intervals from the Fe-plot are inappropriately too narrow and do not have the correct coverage rate. Model-based statistical methods which directly link the treatment variables, dose and number of fractions to the response are advocated.

Dose-Response Relationship, Radiation↗
PubMed1989

Purification of rabbit platelet secretory phospholipase A2 and its characteristics.

It was reported previously that rat platelets release phospholipase A2 upon in vitro stimulation by thrombin, ADP, or A23187 (Horigome, K., Hayakawa, M., Inoue, K., & Nojima, S. (1987) J. Biochem. 101, 53-61). Secretion of phospholipase A2 was also observed with rabbit platelets. Rabbit platelets seem to release phospholipase A2 upon stimulation in vivo, because the rabbit plasma taken immediately after intravenous injection of PAF contained an appreciable level of phospholipase A2 activity and fewer platelets. Rabbit platelet phospholipase A2 released in vitro was purified by column chromatography using Sepharose CL-4B conjugated with anti-rat platelet derived phospholipase A2 monoclonal antibody, followed by reversed-phase HPLC. The purified enzyme was subjected to structural analysis by HPLC peptide mapping and primary sequence determination of the separated peptides. Based on the homology with rat platelet secretory phospholipase A2 (Hayakawa, M., Kudo, I., Tomita, M., Nojima, S., & Inoue, K. (1988) J. Biochem. 104, 767-772), a partial primary structure (62 amino acid residues) of the rabbit enzyme was tentatively determined; the two sequences were highly homologous (72%). The rabbit sequence was also nearly identical to that of rabbit ascitic fluid phospholipase A2, which was determined by Forst et al. (Forst, S., Weiss, J., Elsbach, P., Maraganore, J.M., Reardon, I., & Heinrikson, R.L. (1986) Biochemistry 25, 8381-8385). Phospholipase A2 from the membrane fraction of rabbit platelets was also purified; it had the same characteristics and th same amino-terminal sequence as the purified secretory enzyme. Secretory and membrane-bound phospholipase A2 of rabbit platelets may in fact be identical.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1989

Changes of serum IgG antibody reactivity to protein antigens of Treponema pallidum in syphilis patients after treatment.

The changes of serum IgG antibody reactivity to protein antigens of Treponema pallidum after treatment of syphilis were observed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. Until 9 to 12 months after treatment, it was seen that there was a loss of several antibodies and some diminution in their reactivity in primary, secondary and early latent syphilis, but no changes occurred in late latent and reinfected syphilis. In primary syphilis, there was a significant loss of two IgG antibodies to the treponemal antigens of molecular weights 68,500 and 47,000 at 11 months after treatment. According to our previous study, the treponemal antigen of molecular weight 68,500 was T. pallidum specific and appeared only in primary syphilis, and that of molecular weight 47,000 was one of the major antigens of T. pallidum. The reaction between serum IgG antibodies of 14 patients who had been treated for secondary, early latent and late latent syphilis 2 to 14 years ago and major antigens of T. pallidum was observed and any loss or decrease in reactivity was not discovered. From the results obtained, it was concluded that the observation of serum IgG antibody reactivity to protein antigens of T. pallidum is not helpful in evaluating the efficacy of treatment in secondary, early latent, late latent and reinfected syphilis. However, serum IgG antibodies to treponemal antigens of molecular weights 68,500 and 47,000 could possibly be useful in the assessment of the efficacy of treatment in primary syphilis.

Antibodies, Bacterial↗
PubMed1989

Clinical and morphological features of hypertrophic cardiomyopathy in Korean patients.

Thirty three cases of hypertrophic cardiomyopathy (HCMP) were reviewed to estimate the relative frequencies of the subtypes of HCMP and to clarify whether there is any racial difference in clinical and morphological features of HCMP. The diagnosis was made by echocardiography, cardiac catheterization and left ventriculography. Twenty four patients underwent coronary angiogram. Numbers of cases by the types of HCMP were 20 (61%) with asymmetrical septal hypertrophy (ASH), 11 (33%) with apical hypertrophy (APH) and 2 (6%) with midventricular hypertrophy (MVH). Mean ages of the patients with APH, ASH and MVH were 54, 46 and 31 years respectively, and the differences were statistically significant (p less than 0.05). The giant negative T wave on electrocardiogram was seen in 4 patients (20%) of ASH and 5 patients (45%) of APH. On echocardiogram mean ratio of interventricular septal to left ventricular posterior wall thickness was 1.9 in ASH, 1.2 in APH and 1.6 in MVH, and the differences were statistically significant (p less than 0.05). All patients with APH showed "spade of ace" deformity in left ventriculography. Coronary angiograms were normal in all patients who had the procedure. Our study showed high frequency of APH of which characteristics were similar to those of the Japanese type APH.

Adult↗