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Y Kim

Publications and source records attributed to Y Kim.

At least 847 records · Page 47Linked to original sources
PubMed1987

Altered lipoxygenase metabolites and leukocyte involvement in an acute occlusion-reperfusion model of canine myocardial infarction.

We compared amounts of lipoxygenase products with the extent of leukocyte infiltration in the ischemic myocardium with an occlusion-reperfusion model of open-chest dog. Changes in peripheral leukocyte count and leukocyte function estimated by neutrophil aggregation induced by calcium ionophore A23187 were also examined. The ischemic tissue (120 +/- 40 ng/g, mean +/- SEM) showed a marked increase in 12-hydroxyeicosatetraenoic acid (HETE) production compared with the normal tissue (13 +/- 1 ng/g, p less than 0.01). The production of 5-HETE in the ischemic tissue was also augmented as well. When we examined the correlation between production of either 12-HETE or 5-HETE and leukocyte infiltration in the ischemic tissue, the former was augmented markedly in proportion to the extent of the latter. Leukocyte count in peripheral circulation was gradually increased after reperfusion. Similarly, neutrophil aggregation was significantly augmented during reperfusion. These results indicate that production of lipoxygenase metabolites associated with leukocyte infiltration in the reperfused ischemic tissue was increased during the course of myocardial infarction, which was accompanied by activation of leukocyte in peripheral circulation. Further studies should be done to clarify the importance of lipoxygenase metabolites in the evolution of reperfusion-induced myocardial injury.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1987

[[Recent life expectancy of Koreans in Japan, 1980 and 1985]].

Two abridged life tables for Koreans living in Japan for 1980 and 1985 are constructed using vital statistics and census data. Among the findings are that "the expectations of life at birth of Korean males in Japan are 68.4 in 1980 and 70.3 in 1985, whereas those values of Korean females in Japan are 78.3 in 1980 and 78.7 in 1985, respectively. Recent life expectancies of Koreans in Japan have come to resemble those of Japanese more than those of Koreans in Korea." (SUMMARY IN ENG)

Asia↗
PubMed1986

Primary structure of CTP:CMP-3-deoxy-D-manno-octulosonate cytidylyltransferase (CMP-KDO synthetase) from Escherichia coli.

The gene coding for CTP:CMP-3-deoxy-D-mannooctulosonate cytidylyltransferase (CMP-KDO synthetase), kds B, was previously cloned on a 9-kilobase Pst insert of Escherichia coli DNA into pBR 322 (Goldman, R. C., and Kohlbrenner, W. E. (1985) J. Bacteriol. 163, 256-261). Using a transposon mutagenesis approach we have now located kds B on this insert, which facilitated the isolation and sequencing of a 1.3-kilobase segment of DNA containing kds B and putative RNA polymerase and ribosome binding sites. The primary structure of CMP-KDO synthetase predicted by this nucleotide sequence was verified by amino acid composition and sequence analysis of purified CMP-KDO synthetase and cleavage fragments. Our results show that kds B consists of a 744-base open reading frame coding for a 248-amino acid peptide. The molecular weight of CMP-KDO synthetase calculated from the translated sequence is 27,486, taking into account the loss of the N-terminal methionine. These data define the transcriptional unit of kds B and its translation product in molecular terms, information prerequisite to our understanding of both the mechanism of CMP-KDO formation and the regulation of the KDO metabolic pathway in Gram-negative bacteria.

Amino Acid Sequence↗
PubMed1986

Protein phosphorylation in rat hippocampal synaptic plasma membranes in response to neurohypophyseal peptides.

The effect of arginine vasopressin (AVP) on protein phosphorylation in rat hippocampal synaptic plasma membranes (SPM) was examined. With a crude SPM preparation, AVP (10(-8)-10(-5) M) stimulated phosphorylation of a number of proteins which included a brain-specific protein of 48 kDa called B50 or protein F1, which is thought to be related to synaptic plasticity. Equimolar levels of oxytocin also stimulated B50/F1 phosphorylation. AVP and oxytocin at higher concentrations (10(-4)-10(-3) M) reduced SPM protein phosphorylation. When SPM was treated with both AVP and oxytocin, the effects were not additive; on the other hand, the effects of the phorbol ester (TPA) and AVP were additive. With SPM, partially purified by sucrose density centrifugation, only the inhibitory effect of AVP on B50/F1 phosphorylation was seen. These results suggest that AVP and oxytocin stimulation of B50/F1 phosphorylation requires cellular factors which are removed from SPM during membrane purification. In contrast, the inhibitory mechanism triggered by AVP and oxytocin appears to be associated with, or an integral part of, the synaptic membrane itself. Because the effects on membrane protein phosphorylation with maximal amounts of AVP and oxytocin were not additive, they must bind to the same sites on the membrane. This conclusion is supported by the additivity of the effects of AVP and phorbol ester, since the phorbol ester can act directly on the kinase and does not require a membrane recognition site.

Animals↗
PubMed1986

Solid-phase sequencing on the gas-phase sequencer.

Automated Edman degradation has been successfully used for determining the primary structure of numerous peptides and proteins. Quantitative solid-phase Edman degradation has great potential use for amino acid sequence analysis of synthetic peptides assembled on resin support by the Merrifield procedure. We report here the combined use of a modified gas-phase sequencer program and our improved reversed-phase HPLC analysis for PTH-amino acids to carry out the sequence analysis on synthesized peptide resins. This approach is far more sensitive than using glass beads on the conventional solid-phase sequencer. The peptide was assembled on copoly (styrene-1% divinylbenzene) resin beads at an initial substitution of 0.54 mmol/g. On a routine basis, 10-15 resin beads are used, and a repetitive yield of 94% is obtained: as few as 4 beads can be successfully sequenced. The HPLC PTH-amino acid analysis is sensitive down to subpicomole quantities. This procedure offers a sensitive and rapid analytical tool for checking the purity of peptides as they are being assembled on solid support.

Amino Acid Sequence↗
PubMed1986

Purification of canine surfactant-associated glycoproteins A. Identification of a collagenase-resistant domain.

A procedure for purification of surfactant-associated glycoproteins A from canine surfactant was established utilizing preparative isoelectric focusing as a major purification step in absence of detergents. The proteins migrated as charge trains, isoelectric points 4.2-5.0. Unglycosylated forms of surfactant-associated protein A1 (26 kDa) and glycoproteins A2 and A3 (32-36 kDa) were identified by silver-staining and immunoblot analysis. These forms were demonstrated to be identical polypeptides by fingerprint analysis of 125I-labeled peptides generated by tryptic-chymotryptic digests of the iodinated proteins. Size and charge heterogeneity were related to varying amounts of N-linked complex carbohydrates, including sialic acid, which were sensitive to endoglycosidase F and neuraminidase but resistant to endoglycosidase H. A collagenase-sensitive region was demonstrated which was required for sulfhydryl-dependent oligomerization of the molecule. Collagenase treatment resulted in removal of approx. 10 kDa from the glycoprotein molecule. Collagenase-resistant fragments of 21-23 kDa migrated with carbohydrate-dependent size and charge heterogeneity and were reduced to 16 kDa by endoglycosidase F. Amino acid composition of the surfactant glycoproteins demonstrated high glycine content which was diminished after digestion with collagenase. Several glycine-rich tryptic peptides were isolated by reverse-phase chromatography. Partial sequence information shows Gly-X-Y repeat sequences containing hydroxyproline residues. The major canine surfactant-associated proteins, glycoproteins A contain complex-type N-linked carbohydrate. In addition, a separate collagen-like peptide domain is present and is required for sulfhydryl-dependent oligomerization.

Acetylglucosaminidase↗
PubMed1986

A quantitative method for the analysis of cell shape and locomotion.

A rapid, semiautomated system to quantitate and analyze leukocyte shape and locomotion was developed. Video images of moving leukocytes were obtained using a Vidicon camera mounted on a Nikon phase microscope. The video signal was either inputted directly, or indirectly via a video cassette recorder, to a Datacube video analog-digital, digital-analog converter. A Digital Equipment Corporation LSI 11/23 computer using the RT-11/TSX-Plus operating system and computer programs written in FORTRAN and MARCO assembly language permitted image segmentation, image display, and calculation of position, speed, direction of movement and orientation of each leukocyte at 10 s intervals. These data were stored on a winchester disk for subsequent evaluation of the leukocyte orientation, speed and direction of movement using statistical and graphical methods. The reproducibility of measurements made with the video system was tested by comparison with manual measurements; a correlation coefficient of 0.998 was obtained for the two methods. Rates of chemokinesis were then determined for unstimulated and chemokinetically stimulated polymorphonuclear leukocytes (PMNs) and found to average 12.8 micron/min and 18.1 micron/min, respectively. The high speed, ease of data analysis, and potential for multiparameter evaluation makes this system useful for directly evaluating leukocyte locomotion.

Cell Movement↗
PubMed1986

Predicted role of particular phonons in the strand separation melting of the DNA double helix.

The frequency-dependent vibrational fluctuation of the hydrogen bonds around a nucleation defect for the strand separation melting of a DNA polymer poly(dG)-poly(dC) is studied using a modified self-consistent phonon theory. There are two critical frequency bands around the defect at 340 K which is near the temperature at which the hydrogen bonds in neighboring cells melt. The first band is between 60 cm-1 and 120 cm-1 which is essential for the melting proceeding in +z direction(3'----5' in the G backbone). The second is the band under 20 cm-1 which is important for the melting proceeding in -z direction.

DNA, Superhelical↗
PubMed1986

Calcium binding to cardiac sarcolemmal vesicles: potential role as a modifier of contraction.

Passive Ca binding to cardiac sarcolemmal vesicles isolated from rabbit ventricles was measured under ionic conditions similar to intracellular and extracellular media. The first of two main goals was to evaluate whether certain agents induce changes in Ca binding at the external sarcolemmal surface that might contribute to the overall effect of these agents on cardiac muscle contraction. The agents studied were ouabain, verapamil, nifedipine, Bay K 8644, caffeine, ryanodine, and milrinone over a broad range of concentrations, including concentrations at which these agents exert strong effects on cardiac contractile performance. None of these agents produced significant alterations in Ca binding, such that it is unlikely that any part of their actions can be attributed to changes in Ca binding to the external sarcolemmal surface. In contrast, when [Na] is reduced from 140 mM, sarcolemmal Ca binding increases or decreases depending on what replacement is used to avoid changes of osmolarity. Thus the possible effect of Na reduction on surface Ca must be considered in physiological experiments where extracellular [Na] is changed. The second main goal was to evaluate the effects of membrane potential, Na and Mg on Ca bound to the inner surface of the sarcolemma under ionic conditions similar to those expected intracellularly (e.g., [Ca] = 0.3-5.0 microM). Ca binding was inhibited by physiological concentrations of Na and Mg and was sensitive to membrane potential such that depolarization of a normally polarized cell would cause Ca to be released from these sarcolemmal sites. From a quantitative standpoint, it is not clear whether the effect of depolarization would be to contribute sarcolemmal Ca to the activation of the myofilaments or merely to limit the ability of the inner sarcolemmal surface to buffer the rise in intracellular [Ca] associated with contraction.

Alamethicin↗