Biomedical subjects

Y Kim

Publications and source records attributed to Y Kim.

At least 145 records · Page 8Linked to original sources

PubMed2001

A novel human lysyl oxidase-like gene (LOXL4) on chromosome 10q24 has an altered scavenger receptor cysteine rich domain.

We have identified a novel 14-exon human lysyl oxidase-like gene, LOXL4, on chromosome 10q24. The cDNA and derived amino acid sequence of LOXL4 demonstrates a conserved C-terminal region including the characteristic copper-binding site, lysyl and tyrosyl residues and a cytokine receptor-like domain. One of the four N-terminal SRCR domains contains a 13 amino acid insertion encoded by a short exon not present within the closely homologous LOXL2 and LOXL3 genes. The 3.5-kb LOXL4 mRNA is present in pancreas and testis and at lower levels in several other tissues. Fibroblasts, smooth muscle and osteosarcoma (HOS) cells express LOXL4. No expression was detected in HCT-116 and DLD-1 colon, MCF-7 breast and DU-145 prostate cancer cell lines.

3' Untranslated Regions↗

PubMed2001

Structure of cephalosporin acylase in complex with glutaryl-7-aminocephalosporanic acid and glutarate: insight into the basis of its substrate specificity.

BACKGROUND: Semisynthetic cephalosporins are primarily synthesized from 7-aminocephalosporanic acid (7-ACA), which is obtained by environmentally toxic chemical deacylation of cephalosporin C (CPC). Thus, the enzymatic conversion of CPC to 7-ACA by cephalosporin acylase (CA) would be of great interest. However, CAs use glutaryl-7-ACA (GL-7-ACA) as a primary substrate and the enzyme has low turnover rates for CPC. RESULTS: The binary complex structures of CA with GL-7-ACA and glutarate (the side-chain of GL-7-ACA) show extensive interactions between the glutaryl moiety of GL-7-ACA and the seven residues that form the side-chain pocket. These interactions explain why the D-alpha-aminoadipyl side-chain of CPC yields a poorer substrate than GL-7-ACA. CONCLUSIONS: This understanding of the nature of substrate specificity may be useful in the design of an enzyme with an improved performance for the conversion of CPC to 7-ACA. Additionally, the catalytic mechanism of the deacylation reaction was revealed by the ligand bound structures.

Catalysis↗

PubMed2001

Acemannan purified from Aloe vera induces phenotypic and functional maturation of immature dendritic cells.

Acemannan, a major carbohydrate fraction of Aloe vera gel, has been known to have antiviral and antitumoral activities in vivo through activation of immune responses. The present study was set out to define the immunomodulatory activity of acemannan on dendritic cells (DCs), which are the most important accessory cells for the initiation of primary immune responses. Immature DCs were generated from mouse bone marrow (BM) cells by culturing in a medium supplemented with GM-CSF and IL-4, and then stimulated with acemannan, sulfated acemannan, and LPS, respectively. The resultant DCs were examined for phenotypic and functional properties. Phenotypic analysis for the expression of class II MHC molecules and major co-stimulatory molecules such as B7-1, B7-2, CD40 and CD54 confirmed that acemannan could induce maturation of immature DCs. Functional maturation of immature DCs was supported by increased allogeneic mixed lymphocyte reaction (MLR) and IL-12 production. The differentiation-inducing activity of acemannan was almost completely abolished by chemical sulfation. Based on these results, we propose that the adjuvant activity of acemannan is at least in part due to its capacity to promote differentiation of immature DCs.

Adjuvants, Immunologic↗

PubMed2001

Neuroprotective constituents from Hedyotis diffusa.

In a bioassay-guided search for neuroprotective compounds from medicinal plants, a MeOH extract of whole plants of Hedoytis diffusa yielded five flavonol glycosides, kaempferol 3-O-[2-O-(6-O-E-feruloyl)-beta-D-glucopyranosyl]-beta-D-galactopyranoside (1), quercetin 3-O-[2-O-(6-O-E-feruloyl)-beta-D-glucopyranosyl]-beta-D-galactopyranoside (2), quercetin 3-O-[2-O-(6-O-E-feruloyl)-beta-D-glucopyranosyl]-beta-D-glucopyranoside (3), kaempferol 3-O-(2-O-beta-D-glucopyranosyl)-beta-D-galactopyranoside (4), and quercetin 3-O-(2-O-beta-D-glucopyranosyl)-beta-D-galactopyranoside (5), and four O-acylated iridoid glycosides (6-9). Compounds 1 and 2 are previously unreported natural products, and all nine compounds exhibited significant neuroprotective activity in primary cultures of rat cortical cells damaged by L-glutamate.

Animals↗

PubMed2001

Antibacterial, antitumor and hemolytic activities of alpha-helical antibiotic peptide, P18 and its analogs.

The alpha-helical antibiotic peptide (P18: KWKLFKKIPKFLHLAKKF-NH2) designed from the cecropin A(1-8)-magainin 2 (1-12) hybrid displayed strong bactericidal and tumoricidal activity without inducing hemolysis. The effect of the Pro9 residue at central position of P18 on cell selectivity was investigated by Pro9 --> Leu or Pro9 --> Ser substitution. Either substitution markedly reduced the antibacterial activity of P18 and increased hemolysis, although it did not significantly affect cytotoxicity against human transformed tumor and normal fibroblast cells. These results suggest that a proline kink in alpha-helical antibiotic peptide P18 serves as a hinge region to facilitate ion channel formation on bacterial cell membranes and thus plays an important role in providing high selectivity against bacterial cells. Furthermore, to investigate the structure-antibiotic activity relationships of P18, a series of N- or C-terminal deletion and substitution analogs of P18 were synthesized. The C-terminal region of P18 was related to its antibiotic activity and alpha-helical conformation on lipid membranes rather than N-terminal one. Higher alpha-helicity of the peptides was involved in the hemolytic and antitumor activity rather than antibacterial activity. Except for [L9]-P18 and [S9]-P18, all the designed peptides containing a Pro residue showed potent antibacterial activity, although they did not induce a cytolytic effect against human erythrocyte and normal fibroblast cells at the concentration required to kill bacteria. In particular, P18 and some analogs (N-1, N-2, N-3, N-3L and N-4L) with potent bactericidal and tumoricidal activity and little or no normal cell toxicity may serve as an attractive candidate for the development of novel anti-infective or antitumor agents.

Amino Acid Sequence↗

PubMed2001

What is satisfying about satisfying events? Testing 10 candidate psychological needs.

Three studies compared 10 candidate psychological needs in an attempt to determine which are truly most fundamental for humans. Participants described "most satisfying events" within their lives and then rated the salience of each of the 10 candidate needs within these events. Supporting self-determination theory postulates (Ryan & Deci, 2000)--autonomy, competence, and relatedness, were consistently among the top 4 needs, in terms of both their salience and their association with event-related affect. Self-esteem was also important, whereas self-actualization or meaning, physical thriving, popularity or influence, and money-luxury were less important. This basic pattern emerged within three different time frames and within both U.S. and South Korean samples and also within a final study that asked, "What's unsatisfying about unsatisfying events?" Implications for hierarchical theories of needs are discussed.

Affect↗

PubMed2001

Conditioning with high-dose cyclophosphamide may not be sufficient to provide a long-term remission of paroxysmal nocturnal hemoglobinuria following syngeneic peripheral blood stem cell transplantation.

A patient with paroxysmal nocturnal hemoglobinuria (PNH) received a syngeneic peripheral blood stem cell transplant (PBSCT) with high-dose cyclophosphamide (CY) conditioning. He had a reasonable engraftment and complete hematologic recovery. However, at 12 months after PBSCT, he became symptomatic and peripheral blood cells were almost entirely composed of glycosylphosphatidylinositol-anchored proteins deficient cells. This case suggests that high-dose CY may not exert a significant effect on PNH clones in the long term, although it had been effective in allogeneic BMT. In view of the possible autoimmune basis, it seems to be necessary to include other immunosuppressive therapy including ALG in addition to CY.

Adult↗

PubMed2001

Autonomic activity during human sleep as a function of time and sleep stage.

While there is a developing understanding of the influence of sleep on cardiovascular autonomic activity in humans, there remain unresolved issues. In particular, the effect of time within the sleep period, independent of sleep stage, has not been investigated. Further, the influence of sleep on central sympathetic nervous system (SNS) activity is uncertain because results using the major method applicable to humans, the low frequency (LF) component of heart rate variability (HRV), have been contradictory, and because the method itself is open to criticism. Sleep and cardiac activity were measured in 14 young healthy subjects on three nights. Data was analysed in 2-min epochs. All epochs meeting specified criteria were identified, beginning 2 h before, until 7 h after, sleep onset. Epoch values were allocated to 30-min bins and during sleep were also classified into stage 2, slow wave sleep (SWS) and rapid eye movement (REM) sleep. The measures of cardiac activity were heart rate (HR), blood pressure (BP), high frequency (HF) and LF components of HRV and pre-ejection period (PEP). During non-rapid eye movement (NREM) sleep autonomic balance shifted from sympathetic to parasympathetic dominance, although this appeared to be more because of a shift in parasympathetic nervous system (PNS) activity. Autonomic balance during REM was in general similar to wakefulness. For BP and the HF and LF components the change occurred abruptly at sleep onset and was then constant over time within each stage of sleep, indicating that any change in autonomic balance over the sleep period is a consequence of the changing distribution of sleep stages. Two variables, HR and PEP, did show time effects reflecting a circadian influence over HR and perhaps time asleep affecting PEP. While both the LF component and PEP showed changes consistent with reduced sympathetic tone during sleep, their pattern of change over time differed.

Adolescent↗

PubMed2001

Epstein-Barr virus infection, drug resistance and prognosis in Korean T- and NK-cell lymphomas.

T-cell lymphomas are a biologically heterogeneous group of diseases with varying clinical presentations and outcomes. We tried to understand the effect of Epstein-Barr virus (EBV) on lymphogenesis, prognostic factors and drug resistance of T-cell lymphomas, and to establish their relationship with international prognostic factors. Formalin-fixed paraffin-embedded tissue sections from 35 patients (12 women and 23 men) with T-cell lymphomas were examined to detect the presence of EBV using RNA in situ hybridization for EBV-encoded small nuclear RNA (EBER) 1/2 and immunohistochemical stain for latent membrane protein (LMP)-1. We also tried to establish the expression of p53 and P-glycoprotein (P-gp) using immunohistochemistry. The distribution according to the subgroup was: two T-lymphoblastic lymphomas, 13 NK/T-cell lymphomas, one angioimmunoblastic T-cell lymphoma, 17 peripheral T-cell lymphomas, unspecified, and two anaplastic large cell lymphomas. The EBER was detected in 15 of 35 T-cell lymphomas (42.9%) and among these it was detected in five of 17 nodal lymphomas (29.4%) and 10 of 18 extranodal lymphomas (55.6%). There was close correlation between EBER positivity and NK/T-cell lymphoma (P = 0.032). Expression of LMP was found in a proportion of tumor cells in seven of the 15 EBER-positive cases (46.7%). There was no correlation between EBER expression and complete response (CR rate), but coexpression of EBER and p53 was associated with treatment failure (P = 0.047). The 18 patients (51.4%) with p53 expression had significantly poorer outcomes compared with the 17 patients without p53 expression (CR rate, P < 0.0005; overall survival, P = 0.0102). Twenty of 35 patients (57.1%) were positive for P-gp expression. P-gp expression was significantly associated with treatment failure (P = 0.001) and overall survival (P = 0.0089). Seventeen of 35 patients (48.6%) treated with systemic chemotherapy or radiation therapy achieved a CR after initial treatment. When the prognostic factors were grouped using the international prognostic index, the CR rate was 58.8% for the low risk group, 50.0% for the low-intermediate risk group, 14.3% for the high-intermediate risk group, and 0% for the high risk group. In conclusion, high incidence of EBV was detected among Korean patients with T-cell lymphomas. Our study supports the prediction that patients who express p53 and P-gp have a poorer prognosis than those who do not and this should be considered when treatment strategies for individual patients are selected.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

Quantitative immunoelectron microscopy of type VI collagen in glomeruli in type I diabetic patients.

BACKGROUND: The nature of the extracellular matrix (ECM) accumulating in the glomerular basement membrane (GBM) and mesangium (Mes) in diabetes is unknown. Type IV collagen (Col IV) as estimated by quantitative immunoelectron microscopy was reduced in type I diabetic patients (D) with rapid ("fast-track") compared with slow ("slow-track") development of diabetic nephropathy (DN) lesions and controls (C). Col VI is another ECM component suggested to account for Mes matrix (MM) expansion in DN. METHODS: Col VI ECM density was evaluated in eight "slow-track" {Mes fractional volume [Vv(Mes/glom)] <0.32, duration> 20 years} and seven "fast-track" patients [Vv(Mes/glom)> 0.37, duration <20 years diabetes] and in eight C. Quantitative immunoelectron microscopy was performed using polyclonal antibodies to Col VI. Gold particle density (PDG) in MM and the inner layer (IL) of the GBM was measured using stereologic methods. RESULTS: GBM IL PDG was decreased in both fast-track (1.7 +/- 1.6/microm2, mean +/- SD, P < 0.002) and slow-track (3.9 +/- 2.4, P < 0.02) D versus C (10.8 +/- 7.9). GBM IL PDG was also lower in the fast-track versus slow-track D (P < 0.04). Mes matrix PDG/microm2 was decreased in fast-track D (3.2 +/- 3.6) versus C (14.1 +/- 14.6, P < 0.02); a similar trend was seen in slow-track D (5.7 +/- 5.6, P < 0.1). There was no significant difference in MM PDG between the slow-track and fast-track D. CONCLUSION: Col VI density in MM and GBM is decreased in diabetic patients with slowly and rapidly developing renal lesions. This leaves the nature of ECM accumulation in DN unexplained. At least in part, glomerular ECM compositional change is related to diabetes per se and may be independent of the severity of lesions.

Adult↗

PubMed2001

From the chromosome to DNA: Restriction fragment length polymorphism analysis and its clinical application.

Understanding how chromosomal alterations contribute to acquired and inherited human disease requires the ability to manage the enormous physical and informational complexity of the deoxyribonucleic acid (DNA) packaged within. Important concepts and techniques involved in the analysis of DNA include restriction enzymes, Southern blotting, and restriction fragment length polymorphism/linkage analysis. These techniques have been essential in the understanding and diagnosis of several syndromes associated with the head and neck. The purpose of this article is to introduce DNA structure, describe some techniques fundamental to DNA analysis, and provide a brief overview of the clinical applications of this technology with respect to dentinogenesis imperfecta and oral field cancerization.

Blotting, Southern↗

PubMed2001

Comparison between 1-hour and 24-hour drain clamping using diluted epinephrine solution after total knee arthroplasty.

A prospective study was conducted to determine the optimal clamping time in the drain-clamping method after total knee arthroplasty. In a randomized trial, 44 primary total knee arthroplasties were studied after the drain-clamping method using diluted epinephrine solution was applied for 1 hour or 24 hours. The mean blood loss into the drains was less in the 24-hour group compared with the 1-hour group (35 mL in the 24-hour group and 247 mL in the 1-hour group). No statistically significant difference was found in hemoglobin or hematocrit levels between the 2 groups after surgery. Only 1 patient (4.5%) in the 1-hour group and 2 patients (9.1%) in the 24-hour group received blood transfusion. There were significantly more complications in the 24-hour group (P <.05). Two patients (9.1%) in this group required additional surgery. One-hour clamping is preferable to 24-hour clamping in the drain-clamping method for minimizing complications.

Aged↗

PubMed2001

Effect of genistein analogs on oxygen radical production in leukocytes stimulated by unopsonized zymosan.

Effects of genistein analogs on oxygen radical production have been analyzed in human neutrophils, human monocytes or murine macrophages Raw264.7 stimulated with unopsonized zymosan by lucigenin- and luminol-enhanced chemiluminescence assays. Genistein exhibited IC50 values of 10.7-11.5 microM on the oxygen radical production in human neutrophils, 10.9-11.0 microM in human monocytes, and 14.8-27.3 microM in Raw264.7 cells. Orobol, a genistein analog with an additional hydroxy group at the 3' position, exhibited IC50 values of 3.0-3.3 microM on the oxygen radical production in human neutrophils, 2.8-3.1 microM in human monocytes, and 1.5-3.9 microM in Raw264.7 cells. Genistin and sophoricoside are genistein glycosides with a glucose moiety at 7 or 4' position, respectively. The genistein glycosides exhibited 23-37% inhibitory effects at 100 microM on the oxygen radical production.

Animals↗

PubMed2001

Immunological alterations associated with Plasmodium vivax malaria in South Korea.

Various haematological and immunological studies on patients infected with Plasmodium vivax were undertaken, at diagnosis (day 0), after treatment with chloroquine but during primaquine treatment (day 10) and after all treatment (day 59), in South Korea (where there has been a recent and abrupt increase in the incidence of such infection). The main aims were to gain an understanding of the haemto-immunological alterations of this malarial infection, both before and after treatment, and to identify at least one useful marker for the diagnosis and post-treatment monitoring of P. vivax malaria. Thirty-eight patients with P. vivax malaria were compared with 20, apparently healthy controls. At diagnosis, the patients had lymphopenia, marked eosinopenia (the eosinophil count being correlated with the platelet count) and thrombopenia. Cells of most of the lymphocyte subsets investigated [i.e. CD3+, CD8+, CD19+, CD56+, CD3-/CD56+ and CD8+/CD56+ but not CD4+, CD3+/CD56+ or CD25+] were significantly less common among the lymphocytes of patients at diagnosis than among those of the controls. After initiating treatment, the numbers of CD19+ lymphocytes gradually increased (to normal values by day 59), whereas those of CD3+/56+ lymphocytes remained abnormally low throughout the follow-up period. The proportions of lymphocytes identified as CD4+ appeared to be unaffected by treatment. Although serum concentrations of IgE (and, to a lesser extent, IgM) were elevated in the patients at diagnosis, they were subnormal on day 10 post-treatment and normal at the day-59 follow-up. Serum concentrations of IgG and IgA in the patients were always found to be similar to those in the controls. At diagnosis the serum concentrations of complements C3 and C4 were significantly elevated in the patients. C3 remained at the same high concentration during follow-up but the concentration of C4, like that of IgE, was found to be subnormal on day 10 and normal 7 weeks later. The level of parasitaemia (%) was only found to be significantly correlated with haemoglobin concentration. The observation of eosinopenia with elevated IgE and C4 could be a useful indicator of P. vivax malaria, and treatment response could be followed by serial monitoring of serum concentrations of IgE and C4.

Adolescent↗

PubMed2001

Interactions between mastoparan B and the membrane studied by 1H NMR spectroscopy.

Mastoparan B (MP-B) is an antimicrobial cationic tetradecapeptide amide isolated from the venom of the hornet Vespa basalis. NMR spectroscopy was used to study the membrane associated structures of MP-B in various model membrane systems such as 120 mM DPC micelles, 200 mM SDS micelles, and 3%(w/v) DMPC/DHPC (1:2) bicelles. In all systems, MP-B has an amphiphilic alpha-helical structure from Lys2 to Leu14. NOESY experiments performed on MP-B in nondeuterated SDS micelles show that protons in the indole ring of Trp9 are in close contact with methylene protons of SDS micelles. T1 relaxation data and NOE data revealed that the bound form of MP-B may be dominant in SDS micelles. The interactions between MP-B and zwitterionic DPC micelles were much weaker than those between MP-B and anionic SDS micelles. By substitution of Trp9 with Ala9, the pore-forming activity of MP-B was decreased dramatically. All of these results imply that strong electrostatic interactions between the positively charged Lys residues in MP-B and the anionic phospholipid head groups must be the primary factor for MP-B binding to the cell membrane. Then, insertion of the indole ring of Trp9 into the membrane, as well as the amphiphilic alpha-helical structures of MP-B may allow MP-B to span the lipid bilayer through the C-terminal portion. These structural features are crucial for the potent antibiotic activities of MP-B.

Alanine↗

PubMed2001

Morphologic evaluation and integrin expression profile of renal tubular cells cultured from percutaneous renal biopsy specimen.

Kidney biopsy is an indispensible procedure for making a pathologic diagnosis of renal diseases by fixing and staining the biopsy specimen. However, it is not a routine procedure to culture the cells from a renal biopsy specimen directly, or to utilize the cultured cells for any kind of diagnostic or functional evaluation. In this study, primary culture of the renal tubular epithelial cells was tried from a piece of percutaneous kidney biopsy specimen. Successive passages of the cells were possible until fourth passage. With these cells, morphologic characteristics of the cultured cells and integrin expression profiles were investigated. On light and electron microscopy, these cells were characterized by the cobblestone-like growth, presence of microvilli and tight junction, and the preservation of polarity. Immunohistochemical studies demonstrated the epithelial nature of these cells and particularly their differentiation from renal tubular epithelial cells, of either proximal or distal nephronic segment. The integrin profile confirms the epithelial nature of the cell. We hope that our results facilitate the understanding of pathophysiology of renal tubular cells from the patient directly.

Biopsy↗

PubMed2001

Impact of the term schizophrenia on the culture of ideograph: the Japanese experience.

The ideographic Chinese writing system (in use in Asian countries that account for about a quarter of the world's population) directly expresses the meaning of schizophrenia as "the disease of disorganized mind." The term directly challenges a deeply ingrained concept of personal autonomy, and this is stigmatizing. Japanese psychiatrists are thus reluctant to tell their patients that they are suffering from schizophrenia, and, as a result, no more than 20 percent of sufferers actually do know about their diagnosis. Because taking medication is based on informed consent and the exercise of the patient's autonomy, such lack of information has important negative effects. It is unlikely that this problem can be resolved by education or information alone, and it may well be the case that in cultures using ideographs, the illness will need to be renamed. This article suggests some alternatives.

Attitude to Health↗

PubMed2001

Early c-Fos induction after cerebral ischemia: a possible neuroprotective role.

The role of c-Fos in neurodegeneration or neuroprotection after cerebral ischemia is controversial. To investigate whether early c-Fos induction after ischemia is associated with neuroprotection, rats were subjected to 10 minutes of transient forebrain ischemia and c-Fos expression was examined. Resistant dentate granule cells and neurons in CA2-4 displayed more robust immunoreactivity than vulnerable neurons in the CA1 region of hippocampus during early hours of reperfusion. By 6 hours after reperfusion, c-Fos immunoreactivity was greatly diminished in all areas of the hippocampus. Administration of N-acetyl-O-methyldopamine (NAMDA), a compound previously shown to protect CA1 neurons against ischemia, increased c-Fos immunoreactivity in the CA1 vulnerable region at 6 hours after ischemia and protected SK-N-BE(2)C neurons from oxygen glucose deprivation. Further in vitro study showed that NAMDA potentiated phorbol-12 myristate-13 acetate (PMA)-induced c-Fos expression, AP1 binding activity, and late gene expression determined by chloramphenicol acetyltransferase (CAT) activity from AP1 containing tyrosine hydroxylase promoter-CAT fusion gene in SK-N-BE(2)C neurons. In vivo and in vitro results showed that a neuroprotectant, NAMDA, in concert with another stimulus (for example, ischemia or PMA) up-regulates c-Fos expression and suggested that the early rise of NAMDA-induced c-Fos expression in vulnerable CA1 neurons may account for neuroprotection by means of up-regulating late gene expression for survival.

Animals↗