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Biomedical subjects

H M Kim

Publications and source records attributed to H M Kim.

At least 253 records · Page 14Linked to original sources
PubMed1996

Stimulation of humoral and cell mediated immunity by polysaccharide from mushroom Phellinus linteus.

Polysaccharide was purified from mycelial culture of Phellinus linteus (PL) and its effect on immunocompetence of normal splenocytes was observed. Overall in vitro immune function was enhanced by addition of PL into culture of mouse spleen lymphocyte and i.p. injection into mouse, while beta-glucans and other polysaccharides only raised the level of T lymphocyte-mediated immunity. PL stimulated immune functions of T lymphocytes, such as proliferation of T lymphocyte induced by mixed lymphocytes reaction and cytotoxicity of cytotoxic T cells responding to alloantigen. Nonspecific immune functions mediated by natural killer cells and macrophages were increased by treatment of PL in vivo and in vitro. PL also stimulated humoral immune function positively, such as T-dependent and T-independent primary antibody response, and acted as a polyclonal activator on B cell. PL exhibited a wider range of immunostimulation and antitumor activity than other polysaccharides isolated from Basidiomycetes.

Animals↗
PubMed1996

Synergistic cooperation between thapsigargin and phorbol ester for induction of nitric oxide synthesis in murine peritoneal macrophages.

The biochemical transductional events involved in NO synthesis are not fully understood. These studies, therefore, were undertaken to elucidate the role of intracellular calcium and protein kinase C (PKC) in the induction of nitric oxide (NO) synthesis in murine peritoneal macrophages. Thapsigargin (TG), Ca(2+)-ATPase inhibitor of endoplasmic reticulum, had modest activity on NO synthesis by itself, whereas phorbol ester, PKC activator, alone had no effect. When TG was used in combination with phorbol ester, there was a marked cooperative induction of NO synthesis in a dose-dependent manner. The optimal effect of phorbol ester was shown in the first 6 h after TG treatment. In addition, the ability of TG with phorbol ester on NO synthesis could be mimicked by another chemically unrelated inhibitor of Ca(2+)-ATPase, 2,5-di-(t-butyl)-1, 4-benzohydroquinone, and Ca2+ ionophore, A23187. This increase of NO synthesis was reflected as increased amount of NO synthase (NOS) mRNA, as determined by Northern blotting. Intracellular Ca2+ transient by TG was not affected in the presence or absence of extracellular Ca2+, indicating that TG must be effective on cytosolic Ca2+ pool. In addition, chelation of intracellular Ca2+ by acetoxymethyl ester of 1,2-bis-(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid (BAPTA/AM), an intracellular Ca2+ chelating agent, blocked TG- or TG + PMA-induced NO production. PKC inhibitors such as staurosporine or polymyxin B reduced only the synergistic cooperative effect of TG with phorbol ester without affecting TG-induced NO production. In addition, when the cells were pretreated with phorbol ester before TG treatment, there was no synergy between TG and phorbol ester, indicating that PKC is not directly involved in the expression of NOS but involved in "triggering" signal. Secretion of NO corresponded with tumor cell killing, but TG plus phorbol ester-activated macrophages failed to kill tumor cell targets in the presence of Ng-monomethyl-L-arginine. Collectively, these data illustrate that mobilization of intracellular Ca2+ provides a "priming" signal for induction of NOS gene expression by itself and it also requires PKC as a "triggering" signal for macrophage tumoricidal activity.

Animals↗
PubMed1996

Rapid determination of in vivo and in vitro antibody responses by suspension hemolytic assay.

A suspension hemolytic (SH) assay newly modified in this laboratory was applied to the measurement of primary IgM antibody responses, such as T-dependent, T-independent, and polyclonal B cell responses in in vivo and in vitro assays. All results of the SH assay were equal to those of the conventional plaque-forming cell (PFC) assay. With the SH assay in in vitro assays, we could separately measure the amount of the IgM that had been produced during the whole immunization period and measure the IgM newly produced during the shorter time of the assay. The immunomodulations by dioxin and glycopeptide were accurately evaluated by the SH and the PFC assay. Our study suggested that the SH assay modified in this laboratory was more advantageous because of the simplicity of the assay and better analysis of data than the PFC assay, and could be used as the primary method in studying the effects of pharmaceutical and toxic agents on humoral immune functions.

Animals↗
PubMed1996

Antianaphylactic activity of Poncirus trifoliata fruit extract.

The effect of an aqueous extract of Poncirus trifoliata (L.) Raf. (Rutaceae) fruits (PTFE) on compound 48/80-induced mortality associated with anaphylaxis was studied in rats. PTFE inhibited compound 48/80-induced anaphylaxis 100% with a dose of 1.6 mg/g body weight (BW) 1 h before or 5 min after injection of compound 48/80. PTFE inhibited compound 48/80-induced anaphylaxis almost 100% with doses above 0.4 mg/g BW intraperitoneally administered. PTFE (1-1000 micrograms/ml) also dose-dependently inhibited the histamine release induced by compound 48/80 (5 micrograms/ml) in rat peritoneal mast cells. The level of cAMP in peritoneal mast cells, when PTFE was added, increased transiently, and significantly increased 53-fold at 10 s compared with that of basal cells. Moreover, PTFE inhibited intracellular calcium release induced by compound 48/80. These results suggest that PTFE has antianaphylactic activity by stabilizing the peritoneal mast cell membrane.

Anaphylaxis↗
PubMed1996

Efficient fixation procedure of human leukemia cells in sulforhodamine B cytotoxicity assay.

The fixation procedures in sulforhodamine B (SRB) assay for human leukemia cells were modified to produce more reliable results. It was found that the concentration of the fixative agent, trichloroacetic acid (TCA), was critical in the selective fixation of cellular protein. While a TCA solution of 80% fixed both cells and serum proteins, a 50% solution fixed only cells with a very low interference of the serum proteins. Accordingly, we selected 50% TCA as a fixative agent which made the final absorbance of the SRB assay to be exactly matched to the cell density with a small deviation and a low background. Besides the change of TCA concentration, a precentifugation of microplate just before fixation also improved the previous assay procedures in the two points of view. The 2-h standing step was simply substituted for only 1 min of centrifugation. Both the rapid and slow application of TCA solution in fixation produced the same extents of fixation. In an actual application, these two kinds of modifications in the previous SRB assay procedure were also proved to be effective in the determination of cytotoxicities of doxorubicin by using human leukemias.

Cell Survival↗
PubMed1996

Role of intracellular calcium as a priming signal for the induction of nitric oxide synthesis in murine peritoneal macrophages.

Because the role of intracellular Ca2+ in the two-signal process for the induction of nitric oxide (NO) synthesis is controversial, this study was undertaken to examine the role of Ca2+ in the transcriptional regulation of inducible NO synthase (iNOS) in murine peritoneal macrophages. Treatment of the cells with thapsigargin (TG) or 2,5-di-(t-butyl)-1,4-benzodihydroquinone (tBuBHQ), which are the specific and potent Ca(2+)-ATPase inhibitors of endoplasmic reticulum (ER), showed modest effects on tumoricidal function, whereas TG or tBuBHQ in combination with interferon-gamma (IFN-gamma) or lipopolysaccharide (LPS) showed marked effects on tumoricidal function of the cells. The tumoricidal effects of the activated macrophages were correlated with the amount of NO synthesis, and totally abrogated by the use of NOS inhibitor, NG-monomethyl-L-arginine (NGMMA). The increases in NO synthesis was reflected as increased amounts of iNOS mRNA by Northern blotting. To confirm that iNOS induction was due to the changes in the intracellular Ca2+ level, the acetoxymethyl ester of 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA-AM), an intracellular Ca2+ chelator, was used. Blocking the increase of cytosolic free Ca2+ significantly decreased the induction of NO synthesis. To demonstrate that intracellular Ca2+ acts as a 'priming' signal rather than a 'triggering' signal on the induction of NO synthesis by murine peritoneal macrophages, we designed several experiments. When the cells were treated with TG 6 hr after the treatment with IFN-gamma, there was no increase in NO synthesis. In addition, when the cells were treated with TG or LPS 6 hr after treatment with tBuBHQ, a synergistic increase on NO synthesis was shown only in the case of LPS. When phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, was added to the cells 6 hr after the treatment with TG, there was a marked co-operative induction of NO synthesis, even though PMA alone has no effect. Based on the results obtained in this study, we suggest that cytosolic Ca2+ might be enough for the expression of iNOS gene as a priming signal and PKC might be involved in the induction of NO synthesis as a triggering signal by post-transcriptional modification of iNOS mRNA or iNOS itself in the activated murine peritoneal macrophages.

Animals↗
PubMed1996

Molecular cloning of a metallothionein-like gene from Nicotiana glutinosa L. and its induction by wounding and tobacco mosaic virus infection.

The cloning and characterization of genes expressed in plant disease resistance could be an initial step toward understanding the molecular mechanisms of disease resistance. A metallothionein-like gene that is inducible by tobacco mosaic virus and by wounding was cloned in the process of subtractive cloning of disease resistance-response genes in Nicotiana glutinosa. One 530-bp cDNA clone (KC9-10) containing an open reading frame of 81 amino acids was characterized. Genomic Southern blot hybridization with the cDNA probe revealed that tobacco metallothionein-like genes are present in few or in one copy per diploid genome. Northern blot hybridization detected strong induction of a 0.5-kb mRNA by wounding and tobacco mosaic virus infection, but only mild induction was detected when copper was tested as an inducer. Methyl jasmonate, salicylic acid, and ethylene were also tested as possible inducers of this gene, but they had no effect on its expression. The possible role of this gene in wounded and pathogen-stressed plants is discussed.

Amino Acid Sequence↗
PubMed1996

Acute effect of qigong training on stress hormonal levels in man.

We observed the acute effects of Qigong training on the levels of human endogenous opioid peptides, such as beta-endorphin, and other stress hormones [adrenocorticotrophic hormone (ACTH), cortisol, and dehydroepiandrosterone-sulfate (DHEA-S)] in a group of ChunDoSunBup Qigong trainees. At pre (-10 min), mid (40 min) and post (70 min) time of training, blood was taken for the determination of plasma level of hormones. The level of beta-endorphin was significantly increased during the mid-time of training while the level of ACTH declined at the mid- and post-time of training. Cortisol and DHEA-S were not significantly changed during training. This result suggests that Qigong training, as a stress coping method, affects and plays a role in hormonal regulation related to the maintenance of homeostasis in man.

Adrenocorticotropic Hormone↗
PubMed1996

Inhibition of histamine synthesis by glycyrrhetinic acid in mast cells cocultured with Swiss 3T3 fibroblasts.

The effect of glycyrrhetinic acid (18-O-beta-glycyrrhetinic acid, GA) on histamine metabolism was investigated in cultured mast cells (CMCs) cocultured with Swiss 3T3 fibroblasts. GA strongly inhibited histamine synthesis in the cocultured CMCs. Since 50 microM GA inhibited about 80% of histidine decarboxylase (HDC) activity, the inhibitory activity of GA for histamine synthesis was considered to be derived from the inhibition of HDC activity. The number of berberine-sulfate-positive cells also decreased in the presence of GA, which indicated that maturation of CMCs was inhibited by GA. Furthermore, we examined the effect of GA on the mRNA expression of novel protein kinase C delta (nPKC delta), a major isoform of CMCs, by northern blot analysis. The expression of nPKC delta mRNA in the presence of GA was significantly lower than in the absence of GA. These results suggest the possibility that the inhibition of histamine synthesis by GA is regulated by nPKC delta.

3T3 Cells↗
PubMed1996

Selective suppression of in vitro T-dependent humoral immunity by synthetic food additive antioxidants.

Effect of antioxidants on humoral immune responses, such as butylated hydroxytoluene (BHT), n-propyl gallate (PG) and dimethyl sulfoxide (DMSO) is suppression in vitro antibody production. These antioxidants all inhibited T-dependent B cell response, not T-independent and polyclonal B cell response. These data suggest that antioxidants suppress humoral immunity by suppression of regulation of T cells or action of macrophages on B cells, not by direct suppression of B cells. The other possible explanation for antioxidant action is the lack of T-B cell contact required for the triggering of the B cell response with T-dependent antigens.

Animals↗
PubMed1996

Characterization of the apatite crystals of bone and their maturation in osteoblast cell culture: comparison with native bone crystals.

Calcium phosphate crystals deposited in the organic matrix synthesized by chick bone osteoblasts in culture were studied by x-ray and electron diffraction, Fourier transform infrared spectroscopy and chemical composition. The amounts of mineral phase deposited with time and the extent of calcification (% of mineral phase in the tissue) were also determined as a function of time, as were the nature of the changes in the short range order of the crystals. The amount of mineral deposited and the extent of calcification increased with time; the tissue not only contained more crystals of apatite, but the extent of calcification also increased with time as it does in vivo. After 30 days of culture the extent of calcification in the cell culture matrix was similar to that in late chick embryonic and early postnatal chick tibiae. The nature of the CO3 and HPD4 environments were similar to those found in vivo although the concentrations of these ions and the changes in their concentrations with time appeared to develop more slowly in cell culture than they do in vivo. However, the general overall pathway of maturation was similar in cell culture to that observed in vivo.

Animals↗
PubMed1996

A comparative study of the surgical procedures to treat advanced Kienböck's disease.

We have treated a total of 16 cases of advanced Kienböck's disease, stage III and IV by Lichtman's classification, with triscaphe fusion, tendon ball replacement arthroplasty after excision of lunate, proximal row carpectomy as a salvage procedure and limited wrist fusion, since 1985. All cases were followed for minimal 16 months after each operation. Tendon ball replacement arthroplasty after excision of lunate could not prevent further carpal collapse with persistent chronic wrist pain. The triscaphe fusion or radio-lunate fusion induced a marked limited wrist motion later, and the triscaphe fusion alone was not fit for the treatment of advanced one because of progressive proximal migration of capitate and continuous wrist pain due to ligamentous carpal instability in follow-up. So we tried to simultaneously combine tendon ball replacement arthroplasty after excision of lunate with triscaphe fusion in far advanced Kienböck's disease, and their end results was favorable. Proximal row carpectomy could be done in far advanced Kienböck's disease with reasonably painless wrist motions. The overall end results of proximal row carpectomy are much better than any form of carpal arthrodesis. Conclusively the proper way to treat advanced Kienböck's disease seems to depend on the patient's age, their job and sex, and the stage of disease. And the cause of wrist pain in advanced Kienböck's disease seems due to ligamentous carpal instability rather than osteoarthritis on radio-lunate joint.

Adult↗
PubMed1996

Laser assisted in situ keratomileusis for high myopia.

BACKGROUND AND OBJECTIVE: We present the clinical results of laser assisted in situ keratomileusis (LASIK) to correct myopia of more than -10.00 diopters (D). PATIENTS AND METHODS: Eighteen eyes are included in this study. Pre-operative spherical equivalent was -16.40 D, range from -10.50 to -21.50 D. Hinge corneal cap techniques were used with automated microkeratome (Steinway, USA). The thickness of the flap was 130 microns. The stromal bed was ablated with the OmniMed II excimer laser, using the standard MKM program (Summit Technology, Inc., Waltham, MA). The ablation zone was between 4.2 and 5.0 mm. RESULTS: At 6 months postoperatively, the mean spherical equivalent was +0.14 D with a range of +3.50 to -2.00 D. A result within 2.00 D of the desired correction was achieved in 93% of eyes, while a result within 1.00 D was achieved in 47%. Uncorrected visual acuity was improved in all cases. One eye lost greater than two lines of pre-operative best corrected vision due to macular hemorrhage. CONCLUSION: These data show that the LASIK procedure appears to be effective for correcting high myopia.

Adult↗
PubMed1995

Involvement of protein kinase C during taxol-induced activation of murine peritoneal macrophages.

Taxol has been known to block cell division by stabilizing microtubules with promising anticancer activity. However, taxol has distinct cell cycle-independent effects. Recently, this novel drug has been shown to provide a second signal for murine macrophage activation to tumoricidal activity via L-arginine-dependent nitric oxide (NO) synthesis. To investigate the mechanism of taxol-induced NO synthesis, we evaluated the ability of protein kinase C (PKC) inhibitors such as staurosporine (STSN) or polymyxin B to block taxol-induced effects. Taxol alone had only a small effect, whereas taxol in combination with rIFN-gamma markedly increased NO synthesis in a dose-dependent manner. STSN and polymyxin B decreased NO synthesis, which had been induced by rIFN-gamma plus taxol. Furthermore, prolonged incubation of the cells with phorbol ester, which down-regulates PKC activity, abolished synergistic cooperative effect of taxol with rIFN-gamma on NO synthesis. Synergy between IFN-gamma and taxol was mainly dependent on taxol-induced TNF-alpha secretion because not only the increase of inducible NO synthase (iNOS) gene expression by rIFN-gamma plus taxol was associated with the increased expression of TNF-alpha gene but also taxol-induced NO production was decreased by the treatment of anti-murine TNF-alpha neutralizing Abs. STSN and polymyxin B potently inhibited taxol-induced TNF-alpha secretion and TNF-alpha gene expression as well as iNOS gene expression by rIFN-gamma plus taxol. However, rIFN-gamma plus TNF-alpha-induced NO synthesis was not blocked by STSN or polymyxin B. This result indicates that TNF-alpha-induced signaling for induction of NO synthesis is not dependent on PKC activation, and further suggests that the point at which TNF-alpha acts on the NO synthesis from rIFN-gamma-primed macrophages lies next to the point of PKC activation. In conclusion, the present results strongly suggest that the capacity of taxol to increase NO synthesis from rIFN-gamma-primed macrophages is the result of taxol-induced TNF-alpha secretion via the signal transduction pathway of PKC activation.

Actins↗
PubMed1995

The Fc gamma RI receptor signals through the activation of hck and MAP kinase.

U937 cells differentiated with IFN-gamma (termed U937IF cells) were used to study Fc gamma RI signaling. IFN induces a functional Fc gamma RI receptor signaling pathway in U937 cells, leading to the activation of the respiratory burst. IFN induces the expression of the nonreceptor protein tyrosine kinase, hck, and cross-linking the Fc gamma RI receptor in U937IF cells results in the activation of hck kinase as evidenced by the three- to fivefold increased tyrosine phosphorylation of hck. In vitro kinase assays demonstrate that the specific kinase activity of hck is increased 10-fold after Fc gamma RI stimulation. hck is observed to associate with two prominent tyrosine-phosphorylated proteins, p72 and p95, after Fc gamma RI-activation. Fc gamma RI cross-linking also results in mobility shift in MAP kinase in U937IF cells, suggesting that the Fc gamma RI receptor signals through the activation of MAP kinase. The data suggest that hck, p72, p95, and MAP kinase are involved in signal transduction through the Fc gamma RI receptor.

Amino Acid Sequence↗
PubMed1995

Fibronectin activates murine peritoneal macrophages for tumor cell destruction in the presence of IFN-gamma.

Increasing evidence indicates that interaction of cells with fibronectin (Fn) affects many aspects of cellular responses including growth, morphology, differentiation, and activation. However, it is not known whether Fn could activate macrophages for the tumor cell killing. Here we report that Fn provides a signal for murine macrophage activation to tumoricidal activity. Tumoricidal activity was determined by the release of 51Cr from prelabeled P815 mastocytoma target cells. Fn alone had no effect, whereas recombinant interferon-gamma (rIFN-gamma) weakly induced C57BL/6 murine macrophages to kill P815 mastocytoma cells. However, combination of Fn with rIFN-gamma synergized to activate macrophages to lyse tumor cells in a dose dependent manner. Secretion of nitric oxide (NO) correlated with tumor cell killing, and the activated macrophages failed to kill tumor cell targets in the presence of NG-monomethyl-L-arginine (NGMMA), a competitive inhibitor of NO synthase (NOS). Fn, unlike lipopolysaccharide (LPS), alone had no effect on NO synthesis by itself and did not induce bioactive tumor necrosis factor-alpha (TNF-alpha) secretion from murine peritoneal macrophages. The data illustrate the potential for Fn to activate macrophage-mediated antitumor mechanisms in addition to its better characterized role as a cell adhesion molecule.

Animals↗
PubMed1995

Structural and chemical characteristics and maturation of the calcium-phosphate crystals formed during the calcification of the organic matrix synthesized by chicken osteoblasts in cell culture.

The calcium-phosphate (CA-P) crystals formed in the extracellular organic matrix synthesized by chicken osteoblasts in cell culture were examined after 30, 40, and 60 days of culture by a number of physical and chemical techniques including chemical analyses, X-ray diffraction, transmission electron microscopy of isolated crystals, and resolution-enhanced Fourier transform infrared spectroscopy. The data reveal that the solid inorganic calcium-phosphate phase consists of a very poorly crystalline apatite, having a low carbonate content and containing acid phosphate groups. The chemical and structural characteristics are generally similar to the apatite crystals found in young newly synthesized bone but there were small but significant differences found. The major significant differences noted were the rate at which maturational changes occurred in the crystals formed in cell culture compared with those noted in vivo and in synthetic carbonate apatite crystals equilibrated with the same cell culture medium, and the persistence of labile groups, especially HPO4(-2) ions during a relatively long period of incubation. Despite extensive chemical efforts to degrade the organic constituents and to disperse the individual crystals isolated from the organic matrix constituents, a large proportion of the crystals were found to be organized in both loosely and densely packed relatively large roughly spherical aggregates. A few of the aggregates were organized in the form of fibrils with the crystals oriented with their c-axes roughly parallel to the long axes of the crystal aggregate. With briefer periods of chemical treatment, larger aggregates of crystals were occasionally observed in which there was a distinct axial periodicity of approximately 70 nm. In such collagen-crystal fragments, the crystals were well-oriented with their c-axis roughly parallel to the long axes of the aggregate similar to the organization and relationships between crystals and collagen fibrils in native bone. Isolated crystals were in the shape of thin plates. At the end of 30 days of culture, many of the crystals were clearly larger than those observed in native chick bone, except for those in the very youngest (7- to 8-day-old) embryos. At the end of 40 and 60 days of culture, the crystal habit remained as thin plates but the crystals were predominantly smaller, similar to those found in older embryo and postnatal chicken bone. The marked tendency of the crystals to form relatively large aggregates that resist dispersion by techniques that readily disperse the crystals of bone, and the presence of a significant number of larger crystals has also been observed in studies of calcified cartilage. Resolution enhanced FTIR spectroscopy revealed the presence of a high concentration of labile phosphate groups, especially after 30 days of culture and just after the plateau of mineralization is reached.

Animals↗