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Biomedical subjects

H W Kim

Publications and source records attributed to H W Kim.

At least 91 records · Page 5Linked to original sources
PubMed1997

Suppressive effects of Ganoderma lucidum on proliferation of peripheral blood mononuclear cells.

The basidiocarps of Ganoderma lucidum have been used for prevention and treatment of various diseases in the Orient. Methanolic extracts of this mushroom were applied to human peripheral blood mononuclear cell (PBMC) culture systems in the presence of various immunostimulating or immunosuppressive agents. Phytohemagglutinin-induced cell proliferation was reduced to 14% of that of the control by a GLE fraction that is the neutral component of the methanolic extracts of the carpophores. 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced cell proliferation was inhibited by the fractions of GLA, GLC, GLE and GLG. However none of these fractions inhibited proliferation of the PBMCs stimulated with TPA plus ionomycin (IM). Treatment of the PBMCs with cyclosporin A (CsA) led to blockage of the cell proliferation to 9% of that of the control. When the cells were cultured with the methanolic fractions in the presence of CsA, concentration dependent inhibition of the cell proliferation was observed by the addition of GLE and GLG fractions. On the contrary, the GLH fraction recovered the CsA induced inhibition of the cell proliferation. Taken together, among the methanolic fractions, GLE showed the highest inhibitory activity. This fraction might inhibit the protein kinase C signal pathway and accelerate the CsA signal pathway.

Basidiomycota↗
PubMed1997

Factors associated with subjective burden in siblings of adults with severe mental illness.

Experiences of subjective burden were analyzed in a sample of 164 siblings of persons with serious mental illness. Findings indicated that the well sibling's experience of burden was consistently related to the symptomatology of the ill sibling. In addition, those who viewed the ill sibling's behavior as outside his or control exhibited lower levels of subjective burden than did those who viewed the behavior as within the sibling's control. Implications for research and clinical intervention are discussed.

Activities of Daily Living↗
PubMed1997

Coordinate regulation of SR Ca(2+)-ATPase and phospholamban expression in developing murine heart.

Phospholamban, the regulator of Ca(2+)-adenosinetriphosphatase (ATPase) activity in cardiac sarcoplasmic reticulum (SR), is an important determinant of basal myocardial performance. To determine whether phospholamban expression is developmentally regulated in the mouse and whether such regulation reflects alterations in Ca2+ pump activity, hearts from different stages of development were processed for molecular biological and biochemical studies. Both phospholamban and Ca(2+)-ATPase mRNAs were approximately 40% of adult (100%) levels at birth and gradually increased to approach adult levels by day 15 of development. These changes in transcript levels were indicative of changes at the protein level for both phospholamban and Ca(2+)-ATPase. Analysis of the initial rates of Ca2+ uptake demonstrated that over the course of development the upregulation of Ca(2+)-ATPase correlated with increases in the maximal rates of Ca2+ uptake and the constant apparent stoichiometric ratio of phospholamban to Ca(2+)-ATPase correlated with maintenance of a constant affinity of this enzyme for Ca2+ (0.25 +/- 0.03 microM Ca2+). Furthermore, targeted ablation of phospholamban in the mouse resulted in a much higher affinity of Ca2+ uptake for Ca2+ (0.10 +/- 0.02 microM Ca2+) than that observed in wild-type hearts, and this increased affinity was also maintained across different stages of postnatal development. These findings suggest that phospholamban is a major regulator of the affinity of Ca(2+)-ATPase for Ca2+, and coordinate regulation of the expression levels of these two SR proteins may be necessary for maintaining Ca2+ homeostasis in the developing mammalian heart.

Aging↗
PubMed1997

Decreased whole blood factor IX activity following hemodilution with hemoglobin A-zero in-vitro.

Previous studies of hemoglobin-based oxygen carriers and their effects on coagulation have shown conflicting results. This study re-examined the effect of hemoglobin solution on blood coagulation in whole blood using highly purified human hemoglobin Ao (HbAo). Citrated human whole blood samples were diluted 1:1 with HbAo (7gHb/dl) or human serum albumin (HSA; 5g/dl) as a protein control, and both activated partial thromboplastin time (aPTT) and prothrombin time (PT) were measured using a mechanically based whole blood coagulometer. Multiple runs were performed with the same volunteer donor sample. The mean aPTT time of HbAo-diluted samples (105.9 +/- 19.9 sec., n = 41) was significantly longer than the undiluted controls (46.4 +/- 5.6 sec., n = 54) or HSA-diluted blood (77.1 +/- 12.7 sec., n = 41) indicating an abnormal intrinsic coagulation pathway. There was no significant difference between the PT times of the HbAo and HSA-diluted samples. To examine the cause of the prolonged aPTT times with HbAo dilution, we performed activity assays of intrinsic factors XII, XI, IX, and VIII in a citrated human whole blood system diluted 1/5 and 1/10 with normal saline solution (NSS), and then 1:1 with either HbAo, HSA, or NSS. Only the Factor IX activity was significantly depressed by hemodilution (1/5 HbAo 50.20 +/- 8.11; HSA 61.05 +/- 6.72; NSS 74.75 +/- 9.83. 1/10 HbAo 46.50 +/- 5.57; HSA 64.97 +/- 11.01; NSS 67.92 +/- 16.03). These results suggest that in-vitro hemodilution with HbAo causes a hypocoagulatory response through interference with Factor IX function.

Blood Coagulation↗
PubMed1996

Contributions of asparagine at alpha 97 to the cooperative oxygenation process of hemoglobin.

According to the X-ray crystallographic results from human deoxyhemoglobin, beta 99Asp at the alpha 1 Beta 2 interface forms hydrogen bonds with alpha 42Tyr and alpha 97Asn. To clarify the structural and functional roles of the hydrogen bond between alpha 97Asn and beta 99Asp, we have engineered a recombinant hemoglobin in which alpha 97Asn is replaced by Ala, and have investigated its oxygen-binding properties, and have used proton nuclear magnetic resonance spectroscopy to determine the structural consequences of the mutation. Recombinant Hb (alpha 97Asn-->Ala) shows a milder alteration of functional properties compared to the severely impaired beta 99 mutants of the human abnormal hemoglobins. The addition of inositol hexaphosphate, an allosteric effector, causes recovery of the functional properties of recombinant Hb (alpha 97 Asn-->Ala) almost to the level of human normal adult hemoglobin without this allosteric effector. r Hb (alpha 97 Asn-->Ala) shows very similar tertiary structure around the heme pockets and quaternary structure in the alpha 1 beta 2 interface compared to those of human normal adult hemoglobin. The proton nuclear magnetic resonance spectrum of the deoxy form of this recombinant hemoglobin shows the existence of an altered hydrogen bond which is believed to be between alpha 42Tyr and beta 99Asp at the alpha 1 beta 2 interface. Thus, the present results suggest that the intersubunit hydrogen bond between alpha 97 Asn and beta 99Asp at the alpha 1 beta 2 interface is not as crucial as the one between alpha 42Tyr and beta 99Asp in the deoxy quaternary structure. Preliminary molecular dynamics simulations have been used to calculate the contributions of specific interactions of several amino acid residues in r Hb (alpha 97Asn-->Ala) to the free energy of cooperativity of this recombinant hemoglobin. The results of these calculations are consistent with the experimental results.

Adult↗
PubMed1996

Blood and cell compatibility of gelatin-carrageenan mixtures cross-linked by glutaraldehyde.

Mixtures of gelatin and iota-carrageenan cross-linked by glutaraldehyde were prepared and their physical properties and blood and cell compatibility were compared to gelatin as a control material. According to scanning electron microscopic observation of fracture surfaces, the mixtures were composed of dispersed and continuous domains which might be generated by phase separation of carrageenan. The thermal degradation temperature of iota-carrageenan in the mixtures rose with increasing gelatin content. The swelling process in the mixtures proceeded slower than in gelatin. Tensile strengths of the mixtures, except that containing 50% iota-carrageenan, increased with increased amounts of iota-carrageenan in the mixtures. The iota-carrageenan contents at the surfaces of the mixtures were generally higher than those admixed originally. Static friction coefficients of the mixtures were lower than that of gelatin. Plasma recalcification times of the mixtures were longer than that of gelatin. Platelet adhesion of the mixtures was lower than that of gelatin, while cell adhesion and growth assays using Chinese hamster ovary cells showed that cell adhesion and growth were not dependent on adding iota-carrageenan. It was concluded that blood compatibility of the mixtures increased and cell compatibility did not decrease, compared to gelatin.

Animals↗
PubMed1996

Lipocortin 1 binding sites on human T-cells: the population of cells with the binding sites is larger in CD8+ T-lymphocytes than in CD4+ T-lymphocytes.

Lipocortin 1 (LC1) is believed to be a mediator of glucocorticoids in displaying anti-inflammatory and immune suppressive responses. The existence of specific LC1 binding sites (putative receptor) on monocytes and neutrophils has been reported. We have studied the distribution of LC1 binding sites in human peripheral blood leukocytes by flow cytometry. The population of cells with LC1 binding sites was much larger in monocytes than in lymphocytes in both rheumatoid arthritis patients (93.1 +/- 2.3% vs 8.8 +/- 1.0%) and healthy volunteers (97.0 +/- 0.9% vs 9.9 +/- 1.5%). The LC1 binding cell population was larger in CD8+ T-lymphocytes than in CD4+ T-lymphocytes in both healthy volunteers (26.4 +/- 4.5% vs 10.6 +/- 2.0%) and rheumatoid arthritis patients (28.8 +/- 4.7% vs 8.7 +/- 2.1%). No difference in LC1 binding cell populations was found between rheumatoid arthritis patients and healthy controls.

Annexin A1↗
PubMed1996

Innominate osteotomy for the treatment of Legg-Calvé-Perthes disease.

A retrospective study was performed in 37 patients who underwent innominate osteotomy for the treatment of Legg-Calvé-Perthes disease. The majority of the patients (81%) were more than 6 years old, and the mean age was 7 years and 6 months. Thirty five hips were Catterall group III or IV, and 2 hips that had clinical and radiological "head at risk" signs were group II. The time interval between surgery and the final follow-up ranged from 2 to 6 years with a mean of 3 years and 10 months. Twenty five of 37 patients had good clinical results, and radiographs showed that the sphericity of the femoral head in the older age (> 8 years) group was poorer, which demonstrated a similar pattern to the clinical results in this age group. We conclude that innominate osteotomy is a safe and effective procedure in severe Legg-Calvé-Perthes disease and this operation should be carefully selected as a treatment method in the appropriate age group.

Age Factors↗
PubMed1995

A novel low oxygen affinity recombinant hemoglobin (alpha96val--> Trp): switching quaternary structure without changing the ligation state.

Using our Escherichia coli expression plasmid (pHE2) in which synthetic human alpha and beta-globin genes are coexpressed with the E. coli methionine aminopeptidase gene under the control of separate tac promoters, we have constructed a new artificial hemoglobin in which the valine residue at position 96 of the alpha chain, located in the alpha 1 beta 2 subunit interface, has been replaced by a tryptophan residue using site-directed mutagenesis. We have determined the oxygen-binding properties of this recombinant hemoglobin, r Hb (alpha 96Val-->Trp), and have used proton nuclear magnetic resonance spectroscopy to investigate its tertiary structure around the heme group and the quaternary structure in the alpha 1 beta 2 subunit interface. This artificial hemoglobin shows a low oxygen affinity, but high cooperativity in oxygen binding, and exhibits no unusual subunit dissociation when ligated. Molecular dynamics simulations suggest that the unique oxygen-binding property of r Hb (alpha 96Val-->Trp) may be due to an extra hydrogen bond between alpha 96Trp and beta 99Asp in the alpha 1 beta 2 subunit interface in the deoxy form. Despite the replacement of a small amino acid residue, valine, by a large tryptophan residue in the alpha 1 beta 2 subunit interface, this artificial hemoglobin shows very similar tertiary structure around the heme pockets and quaternary structure in the alpha 1 beta 2 subunit interface compared to those of human normal adult hemoglobin. Another unique feature of this artificial hemoglobin is that the ligated form, e.g. carbonmonoxy form, of this hemoglobin in the oxy-quaternary structure can be converted to the deoxy-like quaternary structure by the addition of an allosteric effector, inositol hexaphosphate, as well as by lowering the temperature in the absence of inositol hexaphosphate, without changing its ligation state. Thus, this recombinant hemoglobin can be used to gain new insights regarding the nature of subunit interactions in the alpha 1 beta 2 interface and the molecular basis for the allosteric mechanism of hemoglobin.

Base Sequence↗
PubMed1995

Hemoglobin mediated vasoactivity in isolated vascular rings.

To define hemoglobin-based oxygen carrier (HBOC) vasoactivity, a preliminary study with isolated vascular ring preparations was performed. Transverse ring segments of pulmonary artery and aorta were obtained from male SD rats, mounted in a tissue bath containing Krebs buffer (pH = 7.4, 37C) and instrumented to isometrically record changes in circumferential tension. Norepinephrine (NE) 0.1-70uM significantly increased vascular tension (N = 8, P < 0.01). Human stroma-free Hb (SFH) at 1.8nM to 1.8uM Hb caused a dose dependent increase in isometric tension while methemoglobin 2nM-1.2uM had no significant effect (P > 0.05). Vessels preconstricted with SFH significantly relaxed (P < 0.05) with sodium nitroprusside, glyceryl trinitrate, and isoproteranol. SFH at micromolar concentration causes substantial vasoconstriction in isolated vessel preparations. The mechanism of SFH mediated vasoactivity appears to involve Hb interaction with endothelium derived nitric oxide and was reversible with nitrogenous vasodilators and a beta receptor agonist indicating pharmacologic modulation may be possible.

Animals↗
PubMed1995

A giant ureteral stone.

A 55-year-old woman suffered from right flank pain and had a right giant ureteral stone with hydronephrosis. Ureterolithotomy was performed. The ureteral stone was 11cm long and weighed 45gm.

Female↗
PubMed1994

Restoring allosterism with compensatory mutations in hemoglobin.

Abnormal human hemoglobins (HBs) with amino acid substitutions in the alpha 1 beta 2 interface have very high oxygen affinity and greatly reduced cooperativity in O2 binding compared to normal human Hb. In such abnormal Hbs with mutations at position beta 99, the intersubunit hydrogen bonds between Asp-beta 99 and Tyr-alpha 42 and between Asp-beta 99 and Asn-alpha 97 are broken, thus destabilizing the deoxyquaternary structure of these Hbs. A molecular dynamics method has been used to design compensatory amino acid substitutions in these Hbs that can restore their allosteric properties. We have designed a compensatory mutation in a naturally occurring mutant Hb, Hb Kempsey (Asp-beta 99-->Asn), and have produced it using our Escherichia coli expression plasmid pHE2. We have determined the O2 binding properties of this recombinant double mutant Hb, Hb(Asp-beta 99-->Asn and Tyr-alpha 42-->Asp) and have used 1H NMR spectroscopy to investigate the tertiary structures around the heme groups and the quaternary structure in the alpha 1 beta 2 subunit interface. Our results clearly show that the Tyr-alpha 42-->Asp replacement can substantially compensate for the functional defect of Hb Kempsey caused by the Asp-beta 99-->Asn substitution. The structural and functional information derived from this recombinant Hb provides insights into the structural basis of allosterism and the design of compensatory amino acid substitutions to restore the functional properties of other abnormal HBs associated with hemoglobinopathies.

Allosteric Regulation↗
PubMed1994

Diminished tyrosine protein kinase activity in T cells unresponsive to TCR stimulation.

Tyrosine phosphorylation is thought to be one of the earliest steps in antigenic activation of T cells. Three nonreceptor tyrosine kinases, p56lck, p60fyn, and ZAP-70, are known to be involved in T cell receptor (TCR) signaling, albeit their functional roles appear to be different. Whereas p60fyn and ZAP-70 are functionally associated with the T cell antigen receptor, p56lck is essential for TCR signaling without being directly coupled to the TCR. We have studied a mutant variant of the Jurkat T cell line (J32-3.2), in which basal activities of p56lck and p60fyn are 2- to 2.5-fold reduced relative to those in its parental line (J32) while basal activity of ZAP-70 remains unchanged, and compared responses of J32-3.2 and J32 to TCR stimulation. We have demonstrated that tyrosine phosphorylation following CD3 cross-linking in J32-3.2 cells was extremely short-lived and thus insufficient for the induction of subsequent physiological responses. This was at least partially due to the diminished tyrosine kinase activity in these cells. A decrease in the activity of src-related kinases was caused primarily by their lower expression, whereas expression of ZAP-70 was unchanged but its response to CD3 cross-linking was diminished, correlating with the deficient tyrosine phosphorylation of the CD3 zeta-chain, recently observed in J32-3.2. These data are consistent with the idea that src-related kinases phosphorylate the zeta-chain, which in turn recruits ZAP-70 required to sustain the signal.

CD3 Complex↗
PubMed1994

Immunologic analysis of anaphylaxis to protamine component in neutral protamine Hagedorn human insulin.

We report the clinical and immunologic analysis of two patients with diabetes who had anaphylaxis to neutral protamine Hagedorn (NPH) human insulin in the absence of allergy to regular insulin. A 36-year-old woman without a recent history of local insulin reactions or interruption of insulin therapy experienced anaphylaxis within 15 minutes of her usual morning dose of subcutaneously administered NPH human insulin. A 62-year-old man with a history of generalized reactions to NPH human insulin and of anaphylaxis to intravenously administered protamine had generalized urticaria after injection of NPH human insulin. Both patients subsequently tolerated Lente human insulin. Skin test results in both patients were negative to regular and Lente insulin preparations but positive to NPH insulin and to protamine at concentrations tested. In vitro assays demonstrated that both patients had markedly elevated serum levels of IgE and IgG to protamine, but not to regular human insulin, and that their IgE antibodies to protamine recognized protamine antigenic determinants in NPH human insulin. We conclude that the anaphylactic reactions to NPH insulin in our patients were mediated by IgE to protamine, which should be a pathogenetic consideration in the evaluation of immediate-type reactions to protamine-containing insulins.

Adult↗
PubMed1994

Coagulation responses of human plasma after hemodilution with hemoglobin solution in-vitro.

To assess the potential for interference of Hb with the normal coagulation mechanism, we performed in-vitro hemodilution tests. Platelet rich plasma (PRP) was prepared from citrated blood samples of 5 normal volunteers diluted 3:1, 1:1, and 1:3 volume ratio with human stroma-free hemoglobin solution (SFH) or human albumin (HSA). Coagulation kinetics and clot strength were assessed with a thrombelastograph (TEG). Extrinsic and intrinsic coagulation factors were assessed measuring prothrombin time (PT) and activated partial thromboplastin time (aPTT) with an optical coagulation timer. Statistical significance was assessed using ANOVA and Neuman-Keuls tests at p < 0.05. At all dilutions, SFH diluted plasma showed significantly prolonged initial rate of clot formation compared to undiluted control or HSA (p < 0.05). However, there was no difference in formed clot strength between SFH and HSA. At high Hb concentrations Hb seems to interfere with the optical measurements of coagulation times (particularly aPTT). SFH appears to interfere with the initial phase coagulation mechanism in human plasma in-vitro; further study is needed to clarify the cause. In measuring coagulation times of plasma containing Hb a non-optical instrument should be considered.

Blood Coagulation↗