Biomedical subjects

S J Yoon

Publications and source records attributed to S J Yoon.

71 records · Page 4Linked to original sources

PubMed1984

Determination of circulating immune complexes, C3 and C4 complement components and anti-DNA antibody in different classes of lupus nephritis.

Circulating immune complexes (CIC) were measured in 237 sera from children who underwent a renal biopsy during the course of systemic lupus erythematosus. CIC-positive sera contained a lower mean level of C3 but not C4. Anti-DNA antibody was similar in CIC-positive and negative sera. The World Health Organization classification of lupus nephritis was used to categorize the biopsies. CIC, C3, C4 and anti-DNA antibody were determined to assess whether they correlated with the severity of renal lesions. Of 25 sera obtained at renal biopsy from patients with classes 2, 3 and 4, 16 were positive for CIC. C3 was significantly lower in classes 3 and 4 than in class 2. C4 was reduced and anti-DNA antibody was present in classes 2, 3 and 4. Determination of the level of C3 but not C4, CIC or anti-DNA antibody correlates with the severity of lupus nephritis seen on renal biopsies. Nevertheless, performance of a renal biopsy is preferred.

Antibodies, Anti-Idiotypic↗

PubMed1983

Characteristics of a benign subtype of dense deposit disease: comparison with the progressive form of this disease.

Pathologic, clinical and serum complement studies were performed on 18 patients with dense deposit disease (DDD). The patients were divided into 3 groups: group A (10 patients who developed end-stage renal failure within 2.9 +/- 1.0 years of onset) group B (3 patients who developed elevated serum creatinines within 6.8 +/- 4.8 years of onset) and group C (5 patients with no evidence of renal insufficiency after 11.0 +/- 1.4 years of follow-up). Renal biopsies from all patients showed intramembranous, electron-dense deposits in glomerular capillary basement membranes. Most group A and B patients presented with a nephritic and/or nephrotic syndrome and followed an active clinical course. In contrast, group C patients presented with either a nephrotic syndrome or asymptomatic proteinuria +/- hematuria and followed a benign course. Sera from group A and B patients contained reduced concentrations of C3 and factor B and large amounts of C3 nephritic factor (NeF) activity. In contrast, serum of group C patients contained normal amounts of C3 and factor B and low levels of C3 NeF activity. These studies show that some patients with DDD (group C) have a benign illness and that they can be identified by serum levels of C3, factor B and C3 NeF activity.

Child↗

PubMed1982

Circulating immune complexes in patients with progressive systemic sclerosis.

Forty-one patients with progressive systemic sclerosis were studied for the presence of immune complexes by the fluid- and solid-phase C1q binding, C1 activation, and the fluid-phase conglutinin assays. Complement activation and autoantibodies were also studied. Immune complexes were detected in only 6 patients (15%); activation of complement was found in 5 others. The clinical and serologic features of patients with complexes were compared with those in whom complexes were not identified. No significant difference was found with respect to serology. Organ involvement was generally more frequent in the group with immune complexes, but the difference was statistically significant only with respect to lung involvement. The present data suggest that, although complement-fixing immune complexes are infrequently detected in progressive systemic sclerosis, they may play a role in the pathogenesis of lung lesions associated with the disease.

Adult↗

PubMedDate not supplied

Internet-based support for bioscience research: a collaborative genome center for human chromosome 12.

This paper describes an approach that provides Internet-based support for a genome center to map human chromosome 12, as a collaboration between laboratories at the Albert Einstein College of Medicine in Bronx, New York, and the Yale University School of Medicine in New Haven, Connecticut. Informatics is well established as an important enabling technology within the genome mapping community. The goal of this paper is to use the chromosome 12 project as a case study to introduce a medical informatics audience to certain issues involved in genome informatics and in the Internet-based support of collaborative bioscience research. Central to the approach described is a shared database (DB/12) with Macintosh clients in the participating laboratories running the 4th Dimension database program as a user-friendly front end, and a Sun SPARCstation-2 server running Sybase. The central component of the database stores information about yeast artificial chromosomes (YACs), each containing a segment of human DNA from chromosome 12 to which genome markers have been mapped, such that an overlapping set of YACs (called a "contig") can be identified, along with an ordering of the markers. The approach also includes 1) a map assembly tool developed to help biologists interpret their data, proposing a ranked set of candidate maps, 2) the integration of DB/12 with external databases and tools, and 3) the dissemination of the results. This paper discusses several of the lessons learned that apply to many other areas of bioscience, and the potential role for the field of medical informatics in helping to provide such support.

Chromosome Mapping↗

PubMedDate not supplied

A comparison of colour duplex ultrasonography after transurethral alprostadil and intracavernous alprostadil in the assessment of erectile dysfunction.

This study aimed to investigate whether transurethral alprostadil could be used for the diagnosis of erectile dysfunction using colour duplex ultrasound. The ultrasonography results were compared after transurethral and intracavernous alprostadil administration in 20 patients with erectile dysfunction. There were no significant differences in the mean peak systolic velocities (PSVs) between the two routes of administration, but the mean end diastolic velocities (EDVs) showed significant differences, with patients treated with transurethral alprostadil having higher EDVs. Linear regression analysis of the PSVs reached following the two routes of administration showed a moderate relationship, but linear regression analysis of the EDVs showed no relationship. We concluded that transurethral alprostadil was an inappropriate vasoactive drug to use with colour duplex ultrasonography for the evaluation of patients with erectile dysfunction because it required a longer scan time and it was less effective and less reliable than intracavernous alprostadil at stimulating complete corporeal smooth muscle relaxation.

Adult↗

PubMedDate not supplied

Comparing risk-adjusted hospital mortality for CABG and AMI patients.

The objectives of this study were to compare the risk-adjusted mortality of coronary artery bypass graft (CABG) and acute myocardial infarction (AMI) patients simultaneously in six hospitals in Seoul, Korea, and to investigate the relationship between these performance measures by developing a predictive model of mortality. The medical records of 749 AMI and 564 CABG patients were reviewed. A predictive model was developed using logistic regression, including 170 variables selected as risk factors for risk adjustment. The validity of our predictive model was demonstrated to be within an acceptable range. The results showed that one hospital with a significantly low AMI mortality rate also had a low CABG mortality rate, while another hospital with a significantly high AMI mortality rate also had a high CABG mortality rate. Our results implied that hospitals providing good-quality medical management of coronary artery disease also provided a good-quality surgical service.

Adult↗

PubMedDate not supplied

The effect of prostaglandin and its inhibitor on antibody-dependent cellular cytotoxicity against human squamous cell carcinoma of head and neck.

The effects of chimeric monoclonal antibodies (cMAbs), prostaglandin E2(PGE2), and indomethacin (INDO) on antibody-dependent cellular cytotoxicity (ADCC) against human squamous cell carcinoma of head and neck (SCCHN) cell line were examined. Using the PCI-50 SCCHN cell line as target and normal human peripheral blood mononuclear cells as the effector, ADCC was enhanced by the treatment of cMAbs (1.25 micrograms/ml), but was inhibited by exogenous PGE2(5 x 10-7M). The effects of cMAb and PGE2 were dose-dependent. Maximal suppression of activity occurred when PGE2 was present during the entire 4 hour 51Cr-release assay period, whereas pretreatment of effector cells with PGE2 had minimal inhibitory effect after washing. These results indicate that decreased ADCC seen with SCCHN targets treated with PGE2 is related to post-binding events, such as binding of effector and target cells. Pre-treatment of effector cells with INDO (1 microgram/ml) resulted in restoration of NK activity which was inhibited by PGE2. Our in vitro results suggest that INDO can increase tumor cell killing by the reversal of the suppression for many immune functions by PGE2.

Antibody-Dependent Cell Cytotoxicity↗

PubMedDate not supplied

Combination gene therapy of IL-12 and allogeneic MHC class I gene via stimulating NK cytolytic activity.

In this study, we tested whether expressing an allogeneic MHC class I gene and/or a cytokine gene in tumor cells could induce anti-tumor immunity. We compared the potential therapeutic benefit of introducing IL-12 or H-2Kb alone and in combination into CT26 tumor cells. Whereas IL-12 expression in CT26 cells delayed the formation of tumors, the expression of class I molecules alone was apparently insufficient to reduce tumorigenicity. The combined expression of IL-12 and H-2Kb, however, more efficiently reduced tumor growth than did either genes alone. Histological examination of tumors expressing IL-12 and H-2Kb showed a non-specific inflammatory reaction, such as a necrosis, and an increased tissue infiltrate of immune effectors. These results suggest that the combined expression of IL-12 and H-2Kb in tumor cells has potential therapeutic benefit.

Adenocarcinoma↗

PubMedDate not supplied

Characterization of the anticancer activity of DW2282, a new anticancer agent.

DW2282 [(S)-(+)-4-phenyl-1-[N-(4-aminobenzoyl) indoline-5-sulfonyl]-4,5-dihydro-2-imidazolone].hydrochloride] was derived from diarylsulfonylurea and was identified as a prominent new anticancer agent. We examined the characteristics of DW2282 activity on the proliferation of human lung carcinoma cells, A549 and human leukemic cells, K562. DW2282 effectively inhibited cancer cell proliferation in vitro. Colony forming assay and viability tests demonstrated that DW2282 is a cytotoxic agent rather than a cytostatic agent. The isotope uptake test exhibited that DW2282 inhibited or inactivated protein synthesis. Also, under conditions which cause RNA or protein synthesis inhibition, by co-treatment with actinomycin D or cycloheximide, reduced the anticancer effects of DW2282. This means that the cytotoxicity of DW2282 depends partially on RNA or protein synthesis and proteins affected by DW2282 may inactivate or alter the process of the synthesis of another protein. DW2282 activity was highly diminished in the presence of colcemid, a metaphase spindle blocker. This result suggests that DW2282 may be related to the cell cycle. After exposure to DW2282, morphologically apoptotic cells appeared in A549 cells and fragmented DNA was detected in K562 cells. It demonstrated that apoptosis is one of the mechanisms by which DW2282 inhibits the proliferation of A549 and K562 cells.

Antineoplastic Agents↗

PubMedDate not supplied

Development of a new plasmid vector with PSA-promoter and enhancer expressing tissue-specificity in prostate carcinoma cell lines.

Differential expression of the desired gene product in the target tissue is central to the concept of gene therapy. One approach is to use a tissue-specific promoter to drive therapeutic genes, such as the p53 tumor suppressor gene. To determine the feasibility of tissue-specific gene therapy for prostate cancer using prostate specific antigen (PSA) promoter and/or enhancer, in this study, we developed a tissue specific expression vector using a PSA promoter and enhancer. Our results showed that the cloned PSA promoter actively drives gene expression in the PSA-producing prostate cancer cell line (LNCaP). However, barely any promoter activity was detected in the non-PSA producing prostate cancer cell lines (DU145, PC-3) or the non-prostate cell lines (HEK-293, SAOS-2). The wild-type p53 gene driven by this PSA-promoter efficiently suppressed the growth of LNCaP. Moreover, p53 driven by the PSA enhancer-promoter cassette more efficiently suppressed the growth of the PSA-producing prostate cancer cell line (LNCaP) in vitro. This suggest that we were able to manage the tissue specificity by PSA enhancer and promoter. Additionally, the juxtaposed enhancer-promoter cassette showed great enhancement of p53 expression and apoptosis in vitro. Taken together, these results show that PSA enhancer-promoter may be a potential tool for gene therapy for prostate cancer.

Adenocarcinoma↗

PubMedDate not supplied

Reduced expression of MHC class I antigen in human cancer cell lines with defective LMP-7.

The function of major histocompatibility complex (MHC) class I molecule is to sample peptides derived from intracellular proteins and to present these peptides to CD8+ T cells. We analyzed twenty-nine human cancer cell lines for expression of the TAP-1/2 and LMP-2/7 genes and identified whether defects in these genes were associated with the level of expression of MHC molecules in cancer cells. Expression of TAP-1 was positive in 86% (25/29) of the cell lines, TAP-2 expression was positive in 82% (24/29), LPM2 was positive in 86% (25/29), and LMP-7 was positive in 52% (15/29) at the cell lines. In fifteen cell lines that expressed LMP-7, the mean fluorescence intensity (MFI) was 825.1 +/- 123.2; however, in the cell lines that lacked LMP-7, the MFI was 314.7 +/- 77.2. These data suggest that the expression level of MHC class I molecules is associated, in most cases, with the loss of the LMP-7 gene but without the loss of the TAP-1, TAP-2 or LMP-2 genes.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Cationic liposome-enhanced adenoviral gene transfer in a murine head and neck cancer model.

The effect of combining adenoviral vector and cationic liposomes on the efficiency of gene transfer to head and neck tumor cells was investigated. Two human and two murine cell lines were used for the screening of gene transfer efficiency using an adenoviral vector. Cationic liposome-enhanced gene transfer was checked using a murine squamous carcinoma cell line, SCCVII/SF. A considerable difference in the efficiency of gene transduction was observed among the cell lines. The combination of DOSPER and adenoviral vector containing human alkaline phosphatase showed a remarkable enhancing effect in gene transfer in vitro and in vivo, compared to the adenovirus alone or control groups. With an improvement in the efficiency of gene transfer, it may be possible not only to enhance the expression of transduced genes, but also to deliver a smaller amount of virus, as a result, reducing toxicity and the immune response against adenovirus.

Adenoviridae↗

PubMedDate not supplied

Effect of GM-CSF and IL-2 co-expression on the anti-tumor immune response.

We evaluated the effect of potential therapeutic genes, GM-CSF and IL-2 respectively, or in combination of both cytokines, on the activation of systemic antitumor responses. CT26 tumor cells were modified to secrete GM-CSF and/or IL-2. The growth rate of the modified tumor cells versus the parental CT26 cells did not show any difference. When we implanted the CT26 tumor cells which secrete either GM-CSF or IL-2, delayed and suppressed tumorigenicity was observed. However, another CT26 cell line which expresses both GM-CSF and IL-2 (CT26/GMCSF/IL-2) did not form any tumor mass in the immunocompetent syngeneic Balb/c mice, showing the potential immune responses. Immunohistochemical examination of the modified tumor masses implanted with the cells expressing GM-CSF or IL-2 showed increased necrosis and infiltration of NK (CD56+) lineage cells and macrophage/monocytes. In the vaccination model, the growth of rechallenged wild-type CT26 was more suppressed int he mice which were injected with GM-CSF or IL-2, however, the wild-type CT26 tumor formed normal tumor mass in the mice vaccinated with CT26/GM-CSF/IL-2 showing acute non-T-cell mediated immune response. As a treatment, we injected those modified tumor cells into the established tumor. There we could find tumor growth suppression by the injection of cytokine-modified CT26 cells, especially by the CT26/GM-CSF/IL-2. In the present study we could induce the eradication of tumorigenicity by the transfection of both GM-CSF and IL-2 genes and a potent role in the growth suppression of an established tumor.

Animals↗

PubMedDate not supplied

Anti-tumor effect associated with down-regulation of MHC class 1 antigen after co-transfection of GM-CSF and IFN-gamma genes in CT26 tumor cells.

We previously reported that co-expression of GM-CSF and IFN-gamma genes in tumors induces a synergistic anti-tumor effect. Interestingly, we have used flow cytometry to identify two kinds of populations of CT26 cells that co-express GM-CSF and IFN-gamma genes: one population (CT26/G/I-down) that expresses very low levels of MHC class I and a second population (CT26/G/I-up) that expresses high levels of H-2Kd antigen. We have compared the anti-tumor effect between CT26/I-up and CT26/G/I-down cells. When wild-type (wt) CT26 cells were injected subcutaneously into Balb/c mice, tumor was formed 5-7 days after injection. However, when both CT26/G/I-up and CT26/G/I-down cells were injected, we did not identify any tumor. The protection' study showed that both CT26/G/I-up and CT26/G/I-down. cells could induce systemic immunity against secondary challenge with unmodified parental tumor cell. CT26/G/I-down cells showed normal expression of the heavy chain of MHC class I (HC), beta2-microglobulin (beta2m) and the TAP gene. Furthermore, in CT26/G/I-down cell, although the MHC molecules were detected normally in the cytoplasmic fraction, no message was detected in the membrane fraction. Pulse-chase experiments showed that class I antigen was normally synthesized like wt CT26 or CT26/G/I-up cells. Based on our results, non-MHC restricted immune effectors might play the major role in synergistic anti-tumor effects with co-expression of GM-CSF and IFN-gamma in CT26 tumor model.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

[A study of psychiatric patients perceived effect and expectancy of activity therapy].

The intent of this descriptive study is to investigate the patients perceived effect and expectance of activity therapy. The subjects for this study were 56 patients from the psychiatric ward in Severance Hospital. The data were collected during the period from June 1, 1991 to January 18, 1992. The effect and expectance of the activity therapy was measured using a questionnaire developed by this study's investigators. The date were analyzed by descriptive statistics, t-test and one-way ANOVA, using the SPSS program. The results of this study can be summarized as following; 1. For motivation for the activity therapy, the response range was from 64.3% to 89.3%, that is, it showed a relatively positive response. 2. For the degree of improvement according to the nurse's method in the activity therapy, it was shown that the nurses need professional skill and meeting after activity therapy. 3. For the relevance of the nurse in the activity therapy, 90% of the subjects had a positive answer for all of the activity therapy except the painting therapy. 4. For the perceived effect of the activity therapy, the following results were obtained. 1) 92% of the subjects had a positive response to the dance therapy, that is-I am vigorous physically. 2) 90% of the subjects had a positive response to the reading therapy, that is-I acquire good ideas and instruction. 3) 98.1% of the subjects had a positive response to the recreation therapy, that is-I am joyful. 4) 88.9% of the subjects had a positive response to the writing therapy, that is-I am interested and become acquainted with other patients. 5) 86.8% of the subjects had a positive response to the occupation therapy, that is-I am happy when I work. 6) 92.6% of the subjects had a positive response to the painting therapy, that is-I can express myself in painting. 7) 87.3% of the subjects had a positive response to the music therapy, that is-I am comforted. 5. For the expectance related to the activity therapy, 97.1% of the subjects had the most positive response to the music therapy which is a pleasant comfortable time. From the above-mentioned findings, it is suggested that psychiatric nurses need to development systematic and professional group activity therapy, and know the patient premorbid hobbies, interests and occupations.

Analysis of Variance↗

PubMedDate not supplied

Momordins inhibit both AP-1 function and cell proliferation.

The activation of Jun/Fos is a crucial factor in transmitting the tumor promoting signal from the extracellular environment to nuclear transcription machinery. One of the final steps in signal transduction is the binding of Jun/Fos to the AP-1 site in order to express gene transcription. Utilizing this concept, we screened about 100 extracts of natural plants to search for a Jun-Fos function inhibitor. The methanol extract of Ampelopsis radix reduced Jun/Foc retardation remarkably. The active principles of the extract were isolated and purified by repeated column chromatography and their structures were identified as oleanolic acid glycosides known as momordin I, Id, and Ie. These compounds reduced the Jun/Fos-DNA interaction and their activities were quantitated with liquid scintillation counting of corresponding bands. Among them, momordin I had the strongest inhibitory activity, with an IC50 value of 22.8 micrograms/ml. The methanol extract and momordin I, Id and Ie also showed cell cytotoxicity against human cancer cell lines. As expected from a gel shift assay, momordin I showed the strongest cytotoxicity and its IC50 value was from 7.280 micrograms/ml to 16.05 micrograms/ml depending on the cell line. With these data, it may be concluded that the mechanism of anticancer activity of momordin I comes from its inhibitory effect on the protein-DNA interaction. The in vivo test was done only with the methanol extract. The extract showed measurable anticancer activity against murine colon cancer. The wet tumor weight reduction rate was 17.73% at 90 mg/kg dose. We suggest that the Jun/Fos-DNA interaction results in cell cytotoxicity.

Cell Division↗

PubMedDate not supplied

Natural killer cell activity depression in peripheral blood and ascites from gastric cancer patients with high TGF-beta 1 expression.

Transforming growth factor beta 1 (TGF-beta 1) has been shown to inhibit the function of various types of cells in vitro such as natural killer (NK) cells. However, this activity has not been well characterized in vivo. Therefore, twenty three patients with advanced gastric adenocarcinoma (AGC), with cytologically-proven malignant ascites, were evaluated in this study. We determined whether the NK activities of their lymphocytes from either peripheral blood or ascites were suppressed by tumor cell TGF-beta 1 expression. We also examined whether NK activity was more suppressed in peripheral blood versus in ascites where tumor cell-derived TGF-beta 1 is potentially more locally concentrated. The expression of TGF-beta 1 mRNA was examined in the tumor cells from the ascitic fluid of the AGC patients. The NK activities of lymphocytes in peripheral blood and ascites were measured by the 4-hour 51Cr-release assay. We determined that eleven of twenty three patients had tumor cells expressing high levels of TGF-beta 1 mRNA. The NK activity in these eleven patients was significantly lower than the NK activity in peripheral blood and ascites from twelve patients with low TGF-beta 1 expression. In addition, the NK activity in malignant ascites was significantly lower than the activity in peripheral blood in these high TGF-beta 1-expressing cancer patients (p < 0.05). We also monitored survival time in these advanced gastric cancer patients. However, the patients with high expression of TGF-beta 1 showed a trend towards reduced survival although this was not statistically significant. The data in this study are consistent with observations in the previous experiments that showed inhibitory effects of TGF-beta 1 on NK activities in vitro, we reported the same phenomenon in patients with advanced gastric cancer.

Adenocarcinoma↗