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Biomedical subjects

S Y Yoon

Publications and source records attributed to S Y Yoon.

At least 37 records · Page 2Linked to original sources
PubMed2001

Up-Regulation of ninjurin expression in human hepatocellular carcinoma associated with cirrhosis and chronic viral hepatitis.

The cDNA clones, which were highly expressed in liver tissues of hepatocellular carcinoma (HCC) patients, were identified using dot hybridization and reconfirmed by Northern blot analysis. One of the clones, ninjurin (nerve injury induced protein), showed a much higher expression level in the liver tissue of HCC patients than in normal liver tissue. Interestingly, the presence of ninjurin mRNA transcripts was detected with high intensity in HCC tissues when combined with viral infection and cirrhosis, but not with a normal liver or HCC tissue unrelated with viral infection and cirrhosis. We produced a N-terminal part of recombinant ninjurin protein, as well as a monoclonal antibody specific to this polypeptide. The intensity of immunohistochemical staining of the liver tumor tissue, and regenerating tissue for the ninjurin protein, was stronger than that of normal liver tissue. These results suggest that ninjurin may play an important role in the development of HCC combined with cirrhosis and viral infection.

Animals↗
PubMed2001

Grb2 dominantly associates with dynamin II in human hepatocellular carcinoma HepG2 cells.

The two SH3 domains and one SH2 domain containing adaptor protein Grb2 is an essential element of the Ras signaling pathway in multiple systems. The SH2 domain of Grb2 recognizes and interacts with phosphotyrosine residues on activated tyrosine kinases, whereas the SH3 domains bind to several proline-rich domain-containing proteins such as Sos1. To define the difference in Grb2-associated proteins in hepatocarcinoma cells, we performed coprecipitation analysis using recombinant GST-Grb2 fusion proteins and found that several protein components (p170, p125, p100, and p80) differently associated with GST-Grb2 proteins in human Chang liver and hepatocarcinoma HepG2 cells. Sos1 and p80 proteins dominantly bind to Grb2 fusion proteins in Chang liver, whereas p100 remarkably associate with Grb2 in HepG2 cells. Also GST-Grb2 SH2 proteins exclusively bound to the p46(Shc), p52(Shc), and p66(Shc) are important adaptors of the Ras pathway in HepG2 cells. The p100 protein has been identified as dynamin II. We observed that the N-SH3 and C-SH3 domains of Grb2 fusion proteins coprecipitated with dynamin II besides Sos1. These results suggest that dynamin II may be a functional molecule involved in Grb2-mediated signaling pathway on Ras activation for tumor progression and differentiation of hepatocarcinoma cells.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Effect of granulocyte colony-stimulating factor on chemotherapeutic activity of cytosine arabinoside in acute leukemic cell lines.

Recent studies have shown the presence of receptors for granulocyte colony-stimulating factor (G-CSF) on lymphoid leukemic cells. To determine the effect of G-CSF on chemotherapeutic activity of cytosine arabinoside (Ara-C) on lymphoid as well as myeloid leukemic cells, we evaluated cell counts, apoptosis, and growth inhibition in HL-60, KG-1, Molt-4, Jijoye, and CCRF-CEM cell lines after incubation with Ara-C (0.1 and 1 micromol/L) and/or 5 ng/mL G-CSE G-CSF potentiated the effect of Ara-C on 2 of 3 lymphoid leukemic cell lines (Molt-4 and Jijoye), whereas it decreased the apoptosis and the effect of Ara-C on myeloid cell lines (HL-60 and KG-1).

Acute Disease↗
PubMed2001

A phase II trial of pirfenidone (5-methyl-1-phenyl-2-[1H]-pyridone), a novel anti-fibrosing agent, in myelofibrosis with myeloid metaplasia.

The anti-fibrotic and cytokine modulatory properties of pirfenidone suggest its usefulness in the treatment of myelofibrosis with myeloid metaplasia (MMM). In a prospective study, 28 patients with MMM were treated with oral pirfenidone. Twelve patients completed 1 year of therapy; 13 were withdrawn because of disease progression and three because of drug intolerance. Only one patient experienced a clinically relevant benefit with respect to anaemia and splenomegaly. The overall lack of clinical benefit correlated with no significant improvement in the bone marrow morphological features of the disease. We conclude that pirfenidone has no significant clinical or biological activity in MMM.

Administration, Oral↗
PubMed2001

Long-term outcome of kidney transplantation in adult recipients with focal segmental glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is an important cause of nephrotic syndrome and end-stage renal disease. FSGS recurrence after renal transplantation has a potentially detrimental course leading to the loss of renal function. In order to establish FSGS recurrence rates and evaluate the course of the disease on living-related-donor renal transplantation in ethnic Korean adults (> or = 18 years), we reviewed our experiences of 27 kidney transplantations with FSGS over the last 15 years. Of the 27 renal allografts, 13 were found to have recurrent FSGS by graft biopsy. In comparison with background data upon patients with and without recurrence of FSGS, the donor age of patients with recurrent FSGS was significantly higher than that of those without recurrence (median, 39 years vs 26, p < 0.05). In terms of, age at transplantation, length of dialysis period, and mode of dialysis no differences were found between recurrent and nonrecurrent cases. The graft survival rate of recipients from a kidney donor of age less than 40 years was significantly higher than that of recipients from a kidney donor of age more than 40 years, at 5 and 10 years, respectively (87% vs 33%, 41% vs 0%, p < 0.05). The association between clinical variables and recurrence was assessed by multiple logistic regression analysis, and donor age was found to be a risk factor of FSGS recurrence (p<0.05). Variables such as HLA-mismatch numbers and immunosuppression were not found to be associated. In conclusion, the recurrence rate of FSGS in adult recipients with FSGS was 48% and patients that received kidney from an older donor appear to be at higher risk of developing recurrence. The use of a renal graft from a younger donor is considered advisable for adult recipients with FSGS.

Adult↗
PubMed2001

A case of mediastinal angiomyolipoma.

Angiomyolipoma is a common tumor of the kidney but has rarely been found in the mediastinum. We report a case of angiomyolipoma of the posterior mediastinum in a 62-year-old woman. She experienced exertional dyspnea and intermittent cough at admission. Computed tomography indicated a tumor located at the left paravertebral and upper posterior mediastinum and MRI imaging demonstrated a mass with low signal intensity in T1-weighted image at T4-5 level. Thoracotomy was done for surgical removal of the tumor and histologic examination revealed a mesenchymal tumor composed of mature fat, capillaries and smooth muscle fibers. The tumor was immunohistochemically positive for CD34 and factor-VIII (for vascular component) smooth muscle actin (for smooth muscle component) and S-100 protein (for fat component). There have been four case reports about mediastinal angiomyolipoma, namely three Japanese cases and one French case. It is suggested that angiomyolipoma could be considered for the differential diagnosis of mediastinal tumors.

Angiomyolipoma↗
PubMed2001

Bone marrow stromal cell distribution of basic fibroblast growth factor in chronic myeloid disorders.

BACKGROUND AND OBJECTIVES: Basic fibroblast growth factor (bFGF) is a multifunctional cytokine that exerts positive regulation in hematopoiesis and that may also have a role in myelofibrosis and angiogenesis. We used bone marrow immunohistochemical stains to obtain additional insight into the cellular distribution of bFGF in both chronic myeloproliferative diseases (CMPD) and myelodysplastic syndrome (MDS). DESIGN AND METHODS: Bone marrow immunohistochemical stains were used to evaluate the cellular distribution of bFGF in 29 patients with CMPD, 31 patients with MDS, and 5 normal controls. RESULTS: The density of bFGF-expressing stromal cells was markedly increased in 74% of the patients with MDS, compared with in only 3% of those with CMPD. In contrast, the density was markedly decreased in 62% of the patients with CMPD (versus 6% in MDS). The staining pattern in normal controls was similar to that in patients with MDS. The presence or absence of associated bone marrow fibrosis did not influence the particular pattern of bFGF expression in either MDS or CMPD. INTERPRETATION AND CONCLUSIONS: These observations suggest that bone marrow stromal cell bFGF expression in patients with CMPD is abnormally decreased and that the particular staining pattern may complement the morphologic distinction between CMPD and MDS.

Adult↗
PubMed2000

Immunohistochemical staining for megakaryocyte c-mpl may complement morphologic distinction between polycythemia vera and secondary erythrocytosis.

Recent studies have shown decreased megakaryocyte expression of the thrombopoietin receptor (c-mpl) in patients with polycythemia vera (PV) but not in those with reactive erythrocytosis. We examined the diagnostic utility of this observation in 22 patients with PV, 7 patients with secondary erythrocytosis (SE), and 10 normal controls. Commercial antibodies against c-mpl were used with standard immunoperoxidase methods. Megakaryocyte c-mpl staining intensity was uniformly moderate-to-strong in the healthy controls and in all the patients with SE. In contrast, staining intensity in 9 patients with PV (41%) was uniformly weak. Furthermore, in 12 of the remaining 13 patients with PV, the c-mpl staining pattern in each case was heterogeneous and was associated with weak staining intensity in more than 20% of the megakaryocyte population. These preliminary data suggest that c-mpl immunostains may complement bone marrow histopathology in distinguishing PV from nonclonal causes of erythrocytosis. (Blood. 2000;96:771-772)

Bone Marrow↗
PubMed2000

Megakaryocyte c-Mpl expression in chronic myeloproliferative disorders and the myelodysplastic syndrome: immunoperoxidase staining patterns and clinical correlates.

The objectives of this study were to expand on recent observations that have suggested decreased thrombopoietin receptor (c-Mpl) expression in megakaryocytes of patients with polycythemia vera (PV) and agnogenic myeloid metaplasia (AMM). We applied an immunoperoxidase method with anti-c-Mpl antibody to 55 bone marrow sections from previously untreated patients with chronic myeloproliferative disorder (CMPD) or myelodysplastic syndrome (MDS). These included 8 patients with PV, 15 with AMM, 9 with essential thrombocythemia, 5 with chronic myelocytic leukemia, 9 with the 5q-syndrome and 9 with MDS with fibrosis. The findings were compared with those in four patients with reactive erythrocytosis (RE), six with immune thrombocytopenic purpura (ITP) and five normal controls. Staining intensity (SI) was moderate to strong both in normal controls and in patients with RE or ITP. In contrast, SI was weak in variable proportions of the megakaryocytes in every one of the aforementioned clonal myeloid disorders. The staining pattern (SP) was relatively uniform in MDS and heterogeneous in CMPD. Neither SI nor SP was significantly correlated with certain clinical or laboratory parameters. We concluded that altered megakaryocyte c-Mpl expression may be a nonspecific phenomenon in various subtypes of both CMPD and MDS. However, the characteristic staining patterns may complement the morphological distinction between clonal and reactive myeloproliferation.

Adult↗
PubMed2000

Correlation between structure of Bcl-2 and its inhibitory function of JNK and caspase activity in dopaminergic neuronal apoptosis.

To examine the correlation between the structure of Bcl-2 and its inhibitory function of c-Jun N-terminal kinase (JNK) and caspase activity, we established a dopaminergic neuronal cell line, MN9D overexpressing Bcl-2 (MN9D/Bcl-2) or its structural mutants. The mutants comprised a point mutation in the BH1 (G145A; MN9D/BH1) or BH2 (W188A; MN9D/BH2) domain and a deletion mutation in the C-terminal (MN9D/C22), BH3 (MN9D/BH3), or BH4 (MN9D/BH4) domain. As determined by the TUNEL (terminal deoxynucleotidyltransferase nick end-labeling) and MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] reduction assay, apoptotic death of MN9D/Neo cells reached 80-90% within 24 h in response to 1 microM staurosporine. Upon staurosporine treatment, JNK activity increased six- to sevenfold over the basal level within 2-4 h. Treatment of MN9D/Neo with both staurosporine and a caspase inhibitor, Z-VAD, attenuated cell death without suppressing JNK activation. Both staurosporine-induced cell death and JNK activation were attenuated in MN9D/Bcl-2. As determined by cleavage of poly(ADP-ribose) polymerase into 85 kDa, Bcl-2 blocked caspase activity as well. When cells overexpressing one of the Bcl-2 mutants were treated with staurosporine, death was attenuated in MN9D/BH1, MN9D/BH2, and MN9D/C22 but not in MN9D/BH3 and MN9D/BH4. Similarly, both JNK and caspase activation were blocked in MN9D/BH1, MN9D/BH2, and MN9D/C22, whereas they were not suppressed in MN9D/BH3 and MN9D/BH4. Taken together, our data indicate that there exists a close structural and functional correlation of Bcl-2 to JNK and caspase activity in staurosporine-induced dopaminergic neuronal cell death.

Apoptosis↗
PubMed2000

If anthropology is global, then so are its ethical dilemmas.

This paper reviews three personal situations of the author as a student: an NGO activist in the women's movement and a UN official working on women's health and tobacco. Each situation, the kinds of ethical issue posed and lessons for the future direction of ethics in anthropology are outlined. The paper argues that applied anthropology is embedded in the position of the field of anthropology within the politics of the State and that this defines the parameters of individual choice. Contradictions in ethical situations and decision-making are posed by changing from the distant observer to active involvement and these may not be resolved by logic alone. Furthermore, governance and defining global ethical standards such as for the behavior of the tobacco multinational corporations is a fascinating new realm for anthropological ethical resolve.

Anthropology↗
PubMed2000

Cellular distribution of platelet-derived growth factor, transforming growth factor-beta, basic fibroblast growth factor, and their receptors in normal bone marrow.

We performed an immunohistochemical study on 5 normal marrow samples and 3 fibrotic marrow samples to investigate the cellular distribution of various isoforms of platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-beta), basic fibroblast growth factor (bFGF), and their corresponding receptors. Immature hematopoietic precursors strongly expressed PDGF-B, all the TGF-beta isoforms, PDGFRbeta, TGFbetaRI and II, and FGFR1, 3, and 4. Megakaryocytes stained primarily for PDGF-B, TGF-beta2-3, and PDGFRbeta. Histiocytes displayed intense TGF-beta1, bFGF, and FGFR2 expression. Fibroblasts and endothelial cells carried receptors for all the aforementioned cytokines. The last 2 cell types also expressed the ligand cytokines to varied degrees.

Bone Marrow Cells↗
PubMed2000

Effect of high blood flow on the expression of endothelial constitutive nitric oxide synthase in rats with femoral arteriovenous shunts.

The effect of high blood flow on the expression of endothelial nitric oxide synthase has been investigated in the femoral arteriovenous shunt (AVS) rats created by inserting U-shaped polyurethane tubes in the left femoral arteries and veins. Three days after inserting the femoral AVS, the mean aortic blood flow rate in the abdominal aorta of the AVS rats was about 2.0 times higher than that in the control rats (110.0 +/- 8.4 ml/min vs 52.7 +/- 2.7 ml/min, p < 0.001). The competitive reverse transcriptase-polymerase chain reaction (RT-PCR) data revealed that the mRNA expression level of the endothelial constitutive nitric oxide synthase (ecNOS) was increased in the aortas of the femoral AVS rats compared to that in the control rats. Western blot analysis using a monoclonal antibody against ecNOS revealed that the ecNOS protein levels were markedly increased in the aortas of femoral AVS rats, but ecNOS protein levels in aortas without endothelium were not significantly increased. Inducible nitric oxide synthase (iNOS) protein was not expressed in the aortic tissues with and without endothelium in the control rats. This iNOS expression was not increased by the high blood flow in the femoral AVS rats. These findings suggest that high blood flow could up-regulate the expression levels of ecNOS mRNA and proteins in femoral arteriovenous shunt rats.

Animals↗
PubMed2000

Women and tobacco: moving from policy to action.

A gender perspective contributes to a better understanding of the epidemiological trends, social marketing strategies, economic policies, and international actions relating to women and the tobacco epidemic. Evidence is provided in this article for the negative impact of tobacco use by women and of passive smoking on the health of women and children. Use of tobacco by women is increasing and this is related to the tobacco industry's aggressive advertising, sponsorship and promotion strategies. Policy directions are proposed in this article. At all levels, a multi-pronged strategy--including changes in legislation and fiscal policies, improvements in gender-sensitive health services, and cessation programmes--should be considered. Much more gender-specific research on tobacco use is needed, particularly in developing countries. Women's empowerment and leadership should be at the centre of all tobacco control efforts and are essential for the success of national programmes and the recently introduced Framework Convention on Tobacco Control.

Adolescent↗
PubMed2000

Bone marrow histochemical studies of fibrogenic cytokines and their receptors in myelodysplastic syndrome with myelofibrosis and related disorders.

Cellular and extracellular alterations of various fibrogenic cytokines have been described in a number of different chronic myeloid disorders that are associated with myelofibrosis. However, the available information related to both myelodysplastic syndrome with myelofibrosis (MDS-f) and bone marrow histochemical analysis is limited. In the current study, bone marrow immunohistochemical staining for platelet-derived growth factor, transforming growth factor (TGF)-beta, basic fibroblast growth factor (bFGF), and their receptors was performed in 9 patients with MDS-f, 9 patients with essential thrombocythemia (ET), 8 patients with 5q- syndrome, and 5 healthy control subjects. In addition, TGF-beta1 messenger RNA (mRNA) analysis was performed in 5 patients, each with MDS-f, myelofibrosis with myeloid metaplasia (MMM), polycythemia vera (PV), ET, and immune thrombocytopenic purpura, and in healthy control subjects. In general, protein and transcript expression patterns were similar to normal patterns and not significantly different among the various disease groups. The only exception was a reduced concentration of bFGF-expressing stromal cells in patients with PV, ET, and MMM.

Adult↗
PubMed1999

Two distinct mechanisms are involved in 6-hydroxydopamine- and MPP+-induced dopaminergic neuronal cell death: role of caspases, ROS, and JNK.

In this study, we examined the possibility that MPTP and 6-hydroxydopamine (6-OHDA) act on distinct cell death pathways in a murine dopaminergic neuronal cell line, MN9D. First, we found that cells treated with 6-OHDA accompanied ultrastructural changes typical of apoptosis, whereas MPP+ treatment induced necrotic manifestations. Proteolytic cleavage of poly-(ADP-ribose)polymerase by caspase was induced by 6-OHDA, whereas it remained uncleaved up to 32 h after MPP+ treatment and subsequently disappeared. Accordingly, 6-OHDA- but not MPP(+)-induced cell death was significantly attenuated in the presence of a broad-spectrum caspase inhibitor, N-benzyloxy-carbonyl-Val-Ala-Asp-fluomethylketone (Z-VAD-fmk). As measured by fluorometric probes, the level of reactive oxygen species (ROS) significantly increased after 6-OHDA treatment. In contrast, the level of dihydroethidium-sensitive ROS following MPP+ treatment remained unchanged while a slight increase in dichlorofluorescin-sentive ROS was temporarily observed. As demonstrated by immunoblot analysis, the level of superoxide dismutase was down-regulated following 6-OHDA treatment, whereas it remained unchanged after MPP+ treatment. Cotreatment of cells with antioxidants such as N-acetylcysteine or Mn(III)tetrakis(4-benzoic acid)porphyrin chloride (MnTBAP, cell-permeable superoxide dismutase mimetic) rescued 6-OHDA- but not MPP(+)-induced cell death, whereas inclusion of catalase or N(G)-nitro-L-arginine had no effect in both cases. In addition, 6-OHDA induced ROS-mediated c-Jun N-terminal kinase (JNK) activation that was attenuated in the presence of N-acetylcysteine or MnTBAP but not catalase or Z-VAD-fmk. In contrast, MPP+ has little effect on JNK activity, indicating that ROS and/or ROS-induced cell death signaling pathway seems to play an essential role in 6-OHDA-mediated apoptosis but not in MPP(+)-induced necrosis in a mesencephalon-derived, dopaminergic neuronal cell line.

1-Methyl-4-phenylpyridinium↗
PubMed1999

Bone marrow effects of anagrelide therapy in patients with myelofibrosis with myeloid metaplasia.

In a prospective study investigating the therapeutic role of anagrelide in myelofibrosis with myeloid metaplasia, 20 patients received anagrelide in daily oral doses of 0.5-3 mg. 17 patients were evaluable and received anagrelide for a median of 2 years (range 0.5-4 years). No patient had a clinically appreciable benefit. Bone marrow (BM) examinations at baseline and after 6 and 12 months of treatment were available for 17, 17 and 12 patients, respectively. In all evaluable cases, BM megakaryocyte number increased after 6 months of anagrelide treatment. Also, Ulex europaeus agglutinin-1 staining of megakaryocytes revealed a left-shifted maturation pattern in most patients with a platelet response to anagrelide. However, megakaryocyte staining intensity for transforming (TGF-beta) and platelet-derived (PDGF) growth factors was not affected consistently by treatment. No patient had a >/=2 grade change in either BM fibrosis or osteosclerosis. These in-vivo data support our previous in-vitro observations that anagrelide interferes with megakaryocyte maturation rather than proliferation. Lack of a positive treatment effect is consistent with the finding that anagrelide did not significantly alter megakaryocyte expression of TGF-beta and PDGF.

Aged↗