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Biomedical subjects

S K Kang

Publications and source records attributed to S K Kang.

At least 37 records · Page 2Linked to original sources
PubMed2002

Optimization of culture medium for cloned bovine embryos and its influence on pregnancy and delivery outcome.

This study was conducted to establish an effective culture system for supporting in vitro development of cloned bovine embryos and to evaluate whether improved development in the optimal culture system could contribute to enhancing pregnancy and delivery outcomes after transfer. Enucleated oocytes at the metaphase II stage were reconstructed with serum-starved ear fibroblasts and cloned embryos were subsequently cultured for 168 h in vitro. In Experiment 1, cloned embryos were cultured in either modified Charles Rosenkrans 2 amino acid medium (mCR2aa) or modified synthetic oviduct fluid medium (mSOF). More (P < 0.05) 2-cell embryos (78% versus 92%), morulae (51% versus 69%) and blastocysts (2% versus 39%) were obtained after culture in mSOF than after culture in mCR2aa. In Experiment 2, cloned embryos were successively cultured in mSOF supplemented with various macromolecules during different periods of culture. A successive culture of oocytes in BSA-containing medium for 72 h and then in FBS-containing medium for the next 96 h yielded a higher rate of blastocyst formation (49% versus 25-36%) than other combinations (BSA to BSA or PVA to PVA, BSA or FBS). This macromolecule supplementation also significantly increased the number of total blastomeres (117.3 cells/blastocyst) and inner cell mass cells (ICM, 49.7 cells/blastocyst), and the ratio of ICM cells to trophoblast cells (TB, 0.98). In Experiment 3, a total of 85 blastocysts obtained from each 2-step culture were transferred individually to recipient cows at the end of the culture period and 32 pregnancies (38%) were diagnosed on Day 60 after transfer. However, no (P > 0.05) significant differences due to culture were apparent in the pregnancy outcome. Although six calves were produced using the 2-step culture regime of either BSA-BSA or PVA-FBS, no calves were produced using the successive culture of BSA then FBS, which optimized preimplantation development. In conclusion, mSOF has more potential to support the development of clone embryos than mCR2aa, and successive supplementation of BSA and FBS to mSOF further promotes blastocyst formation. However, enhanced development in vitro might not directly contribute to improving pregnancy outcomes.

Animals↗
PubMed2002

The role of cytokines in the changes in bone turnover following bone marrow transplantation.

Osteoporosis is a common disease among patients undergoing transplantation and a loss of bone mass is usually detected after bone marrow transplantation (BMT), particularly during the immediate post-BMT period. Post-BMT bone loss is primarily related to gonadal dysfunction and immunosuppression. Cytokines, especially interleukin 6, play an important role in the pathogenesis of postmenopausal osteoporosis. However, the pathogenetic role of cytokines in post-BMT bone loss is unknown and data on the changes of cytokines in accordance with bone turnover markers are scarce. The aim of this study was to assess the relationship between bone turnover markers and cytokines, which are regularly sampled at peripheral blood and bone marrow before and after allogeneic BMT. This prospective study included two analyses. The first was a study of 46 BMT recipients (M/F 28/18), examining the relationship between bone turnover markers and serum cytokines that were measured before and at 1 week, 2 weeks, 3 weeks, 4 weeks and 3 months after BMT. Serum intact parathyroid hormone was measured before BMT and at 3 weeks after BMT and its relation to other cytokines and bone turnover markers was evaluated. The second analysis was a study of 14 (M/F 9/5) of 46 patients in whom bone marrow plasma cytokines [interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-alpha)] were measured at 3 weeks after BMT. The relationship between bone marrow plasma cytokines and bone turnover markers was studied because bone marrow is the microenvironment where the real changes in bone turnover occur. Serum type I collagen carboxyterminal telopeptide (ICTP), a bone resorption marker, increased progressively until 4 weeks (peak) after BMT and then decreased thereafter. Serum osteocalcin, a bone formation marker, decreased progressively until 3 weeks after BMT and then increased thereafter. Serum IL-6 increased until 2 weeks after BMT and declined thereafter. Serum TNF-alpha increased until 3 weeks after BMT and declined thereafter. There was a significant positive correlation between serum ICTP and bone marrow IL-6 levels at 3 weeks after BMT, when a marked change in bone metabolism occurs following BMT. However, a correlation between bone turnover markers and bone marrow TNF-alpha or peripheral blood cytokines was not found. At 3 months after BMT, there was a significant negative correlation between the mean daily steroid dose and the serum osteocalcin level (r = -0.43, p < 0.05). The correlation between the Mean daily steroid dose and serum ICTP was also significant (r = 0.41, p < 0.05). Our data suggest that the progressive increase in bone resorption during the immediate post-BMT period is related to both steroid dose and the increase in bone marrow IL-6, which is a potent stimulator of bone resorption in vivo.

Adult↗
PubMed2002

Coexistence of CD30-positive anaplastic large cell lymphoma and mycosis fungoides.

Primary cutaneous T-cell lymphomas, including lymphomatoid papulosis, mycosis fungoides and CD30+ anaplastic large cell lymphoma (ALCL) overlap clinicopathologically and form part of a spectrum of lymphoproliferative disorders. There have been several case reports of these diseases coexisting. We describe a 59-year-old Korean man who presented with a recurrent, solitary CD30+ ALCL of 25 years' duration as well as patch stage mycosis fungoides of 11 years' duration. Such occurrences may represent different clinical manifestations of the same clonal T-cell abnormality, and provide further insight into the pathogenesis of these related disorders.

Humans↗
PubMed2001

Cisplatin-induced apoptosis by translocation of endogenous Bax in mouse collecting duct cells.

cis-platinum(II) (cis-diammine dichloroplatinum; cisplatin) is a potent antitumor compound that is widely used for the treatment of many malignancies. An important side-effect of cisplatin is nephrotoxicity, which results from injury to renal tubular epithelial cells and can be manifested as either acute renal failure or a chronic syndrome characterized by renal electrolyte wasting. Recently, apoptosis has been recognized as an important mechanism of cell death mediating the antitumor effect of cisplatin. This study was undertaken to examine the mechanisms of cell death induced by cisplatin in M-1 cells, which were derived from the outer cortical collecting duct cells of SV40 transgenic mice. Treatment of M-1 cells with high concentrations of cisplatin (0.5 and 1 mM) for 2 hr led to necrotic cell death, whereas a 24-hr treatment with 5-20 microM cisplatin led to apoptosis. Antioxidants protected against cisplatin-induced necrosis, but not apoptosis, indicating that reactive oxygen species play a role in mediating necrosis but not apoptosis induced by cisplatin and that the mechanism of cell death induced by cisplatin is concentration dependent. The low concentrations of cisplatin, which induced apoptosis in M-1 cells, did not affect the expression levels of Bcl-2-related proteins and did not activate c-Jun NH2-terminal kinase (SAPK/JNK). Cisplatin induced the translocation of endogenous Bax from the cytosolic to the membrane fractions and, subsequently, the release of cytochrome c. Overexpression of Bcl-2 blocked cisplatin-induced apoptosis and Bax translocation. These observations suggest that the subcellular redistribution of Bax is a critical event in the apoptosis induced by cisplatin.

Animals↗
PubMed2001

Acute urinary toxicity following transperineal prostate brachytherapy using a modified Quimby loading method.

PURPOSE: To examine the acute urinary toxicity following transperineal prostate implant using a modified Quimby loading method with regard to time course, severity, and factors that may be associated with a higher incidence of morbidity. METHODS AND MATERIALS: One hundred thirty-nine patients with prostate adenocarcinoma treated with brachytherapy from 1997 through 1999 had follow-up records available for review. Patients considered for definitive brachytherapy alone included those with prostate specific antigen (PSA) < or = 6, Gleason score (GS) < or = 6, clinical stage < T2b, and prostate volumes generally less than 40 cc. Patients with larger prostate volumes were given neoadjuvant antiandrogen therapy. Those with GS > 6, PSA > 6, or Stage > T2a were treated with external beam radiation therapy followed by brachytherapy boost. Sources were loaded according to a modified Quimby method. At each follow-up, toxicity was graded based on a modified RTOG urinary toxicity scale. RESULTS: Acute urinary toxicity occurred in 88%. Grade I toxicity was reported in 23%, grade II in 45%, and grade III in 20%, with 14% requiring prolonged (greater than 1 week) intermittent or indwelling catheterization. Overall median duration of symptoms was 12 months. There was no difference in duration of symptoms between patients treated with I-125 or Pd-103 sources (p = 0.71). After adjusting for GS and PSA, multivariate logistic regression analysis showed higher incidence of grade 3 toxicity in patients with larger prostate volumes (p = 0.002), and those with more seeds implanted (p < 0.001). Higher incidence of prolonged catheterization was found in patients receiving brachytherapy alone (p = 0.01), with larger prostate volumes (p = 0.01), and those with more seeds implanted (p < 0.001). CONCLUSION: Interstitial brachytherapy for prostate cancer leads to a high incidence of acute urinary toxicity, most of which is mild to moderate in severity. A prolonged need for catheterization can occur in some patients. Patients receiving brachytherapy alone, those with prostate volumes greater than 30 cc, and those implanted with a greater number of seeds have the highest incidence of significant toxicity.

Acute Disease↗
PubMed2001

Differential expression of activin/inhibin subunit and activin receptor mRNAs in normal and neoplastic ovarian surface epithelium (OSE).

Ovarian surface epithelium (OSE) is the tissue of origin for the majority of ovarian cancers. The mechanism underlying the neoplastic transformation of OSE to ovarian cancer is poorly understood. Activin, a member of the transforming growth factor-beta superfamily, has been shown to increase cell proliferation in ovarian cancer cells. The present study was carried out to investigate the expression and regulation of activin/inhibin subunits and activin receptors in normal and neoplastic OSE. Using reverse transcriptase-polymerase chain reaction and Southern blot analysis, the mRNA levels of alpha, betaA and betaB subunits and activin receptor type IIA and IIB were analyzed in normal OSE and the ovarian cancer cell line, OVCAR-3 cells. The alpha and betaA subunits were highly expressed in normal OSE when compared to OVCAR-3 cells. By contrast, betaB subunit was highly expressed in OVCAR-3 cells, when compared to normal OSE cells. Interestingly, activin receptor IIB mRNA levels were significantly higher in OVCAR-3 when compared to normal OSE cells, whereas activin receptor IIA mRNA levels were the same in both cell types. To characterize the growth modulatory role of activin during neoplastic progression, normal OSE and OVCAR-3 cells were treated with recombinant human activin A (rh-activin A). At concentrations of 1,10 and 100 ng/ml, rh-activin A stimulated the growth of OVCAR-3 cells, but not of normal OSE. Treatment with follistatin, binding protein of activin, attenuates the stimulatory effect of activin. To determine whether the growth stimulatory action of activin in the neoplastic OSE is mediated via an autocrine regulatory mechanism, OVCAR-3 cells were treated with rh-activin A in a dose- and time-dependent manner and the expression levels of activin/inhibin subunits and activin receptors were investigated. Treatments with activin increased the alpha and betaA subunit mRNA levels in a dose- and time-dependent manner. However, no difference was observed in levels of betaB subunit, or in activin receptor type IIA and IIB mRNAs following activin treatments in OVCAR-3 cells. Taken together, these results suggest that different levels of activin/inhibin and activin receptor isoforms are expressed in normal and neoplastic OSE cells. In addition, the altered expression of the activin/inhibin subunits, as well as the cell proliferative effect of activin observed in OVCAR-3 but not in normal OSE cells, indicate that activin may act as an autocrine regulator of neoplastic OSE progression.

Activin Receptors↗
PubMed2001

Palladium(0)-catalyzed carbonylation-coupling-cyclization of allenic sulfonamides with aryl iodides and carbon monoxide.

[reaction: see text] alpha-Allenic sulfonamides undergo carbonylation-coupling-endo-cyclization with aryl iodides in the presence of Pd(PPh(3))(4) (5 mol %), K(2)CO(3), and CO (20 atm) to form 3-aroyl-2- or 3-pyrrolines. Alternatively the carbonylation-coupling-exo-cyclization of gamma- and delta-substituted sulfonamides under the same conditions afforded pyrrolidine- or piperidine-substituted enones.

Journal Article↗
PubMed2001

Reproducible fabrication of miniaturized glucose sensors: preparation of sensing membranes for continuous monitoring.

The immobilization process of glucose oxidase(GOx) in the poly(1,3-diaminobenzene) (poly(1,3-DAB)) network was closely investigated in situ using an electrochemical quartz crystal microbalance(EQCM). GOx captured in approximately 50 nm thick poly-1,3-DAB layer causes a 514 Hz frequency increase, corresponding to 541 ng, and distributes mostly in the outer part of the polymer film. The presence of poly-L-lysine and glutaraldehyde during electropolymerization of poly(1,3-DAB) improves sensitivity by raising the amount of GOx immobilized. Adding a protective membrane on to the enzyme layer from poly(tetrafluoroethylene) (PTFE) dispersed in aqueous media lets the entire fabrication procedure finish perfectly without nonaqueous solvent. The finalized needle-type glucose sensors show competent functions in sensitivity, stability, biocompatibility, lifetime, interference and reproducibility.

Biosensing Techniques↗
PubMed2001

Changes in autoimmune thyroid disease following allogeneic bone marrow transplantation.

Autoimmune diseases can be transmitted and eliminated by bone marrow transplantation (BMT). There have been several cases of autoimmune thyroid disease (AITD) occurring after BMT, but AITD remission has been rarely reported. We present four cases in which the remission or transfer of AITD occurred after an allogeneic BMT. Two patients with severe aplastic anemia (SAA) showed evidence of remission of Hashimoto's thyroiditis which they had before allogeneic BMT. One patient with SAA, which developed during treatment with propylthiouracil for Graves' disease, underwent allogeneic BMT and showed evidence of Graves' disease remission following BMT. In one patient, new AITD occurred after an allogeneic BMT from an HLA-matched sibling who already had AITD. These cases support the evidence that the immune system is newly reconstituted after BMT, and severe autoimmune disease can be an indication for BMT. To fully understand the real changes in autoimmune status after BMT, long-term prospective studies are necessary.

Adolescent↗
PubMed2001

Helicobacter pylori-associated iron-deficiency anemia in adolescent female athletes.

OBJECTIVE: The objective was to investigate the role of Helicobacter pylori infection in iron-deficiency anemia (IDA) of pubescent athletes. STUDY DESIGN: Blood sampling and a questionnaire survey were performed on 440 regular high school students and 220 athletes of a physical education high school. Hemoglobin, serum iron, total iron-binding capacity, ferritin, and immunoglobulin G antibody to H. pylori were measured to compare the prevalence of IDA and H. pylori infection in the groups. Nutritional analysis and a questionnaire survey for socioeconomic status were undertaken to compare and control for other risk factors that might influence IDA and H. pylori infection in the groups. In those with IDA coexistent with H. pylori infection, we also determined whether IDA can be managed by H pylori eradication. RESULTS: The prevalence rates of IDA, H pylori infection, and H. pylori -associated IDA in female athletes were higher than in the control group. The relative risk of IDA was 2.9 (95% CI, 1.5 to 5.6) for those with H. pylori infection. Athletes who exhibited H. pylori -associated IDA showed significant increases in hemoglobin, iron, and ferritin levels after H. pylori eradication. The subjects in the control group who were treated orally with iron alone showed no significant changes. CONCLUSION: Adolescent female athletes may have development of H. pylori -associated IDA, which can be managed by H. pylori eradication.

Adolescent↗
PubMed2001

Expression of bisecting N-acetylglucosaminyltransferase-III in human hepatocarcinoma tissues, fetal liver tissues, and hepatoma cell lines of Hep3B and HepG2.

In this paper, uridine diphosphate (UDP)-N-acetylglucosamine/beta-D-mannoside beta-1,4 N-acetylglucosaminyltransferase III (GlcNAc-transferase-III C 2.4.1.144) activity was determined in human hepatoma cell lines of Hep3B and HepG2, and also compared with those of normal liver tissues and primary hepatocytes. GlcNAc-transferase-III enzymes of Hep3B and HepG2 were mainly detected in the membrane fraction. When GlcN,GlcN-biant-PA and UDP-GlcNAc were used as substrates, the Km values (4.7 mM for UDP-GlcNAc and 1.1 mM for GlcN, GlcN-biant-PA) of Hep3B GlcNAc-transferase-III were distinguishable from those of HepG2 GlcNAc-transferase-III (6.8 mM for UDP-GlcNAc and 3.4 mM for GlcN,GlcN-biant-PA). Furthermore, Hep3B enzyme in membrane fraction showed about 1.5-fold higher specific activity (1423 pmol/hr/mg) than that of HepG2 (1066 pmol/hr/mg). Normal liver cells and primary adult hepatocytes are characterized by a very low level of GlcNAc-transferase-III activity, whereas human hepatoma cells exhibited high activities. These data were supported by reverse transcription-polymerase chain reaction results, showing that expression of the GlcNAc-transferase-III mRNA increased in proportion to the enzymatic activities. Although the mechanism underlying the induction of this enzyme is unknown, lectin blot analysis showed that oligosaccharides in many glycoproteins were observed in hepatoma cells. By treating hepatocarcinoma cultures that express GlcNAc-transferase-III with inhibitors (tunicamycin, deoxymannojirimycin, and swainsonine) of different steps of the glycosylation, we provide evidence that expression of GlcNAc-transferase-III mRNA is dependent on glycosylation of cellular proteins.

Adult↗
PubMed2001

Ovarian surface epithelium: biology, endocrinology, and pathology.

The epithelial ovarian carcinomas, which make up more than 85% of human ovarian cancer, arise in the ovarian surface epithelium (OSE). The etiology and early events in the progression of these carcinomas are among the least understood of all major human malignancies because there are no appropriate animal models, and because methods to culture OSE have become available only recently. The objective of this article is to review the cellular and molecular mechanisms that underlie the control of normal and neoplastic OSE cell growth, differentiation, and expression of indicators of neoplastic progression. We begin with a brief discussion of the development of OSE, from embryonic to the adult. The pathological and genetic changes of OSE during neoplastic progression are next summarized. The histological characteristics of OSE cells in culture are also described. Finally, the potential involvement of hormones, growth factors, and cytokines is discussed in terms of their contribution to our understanding of the physiology of normal OSE and ovarian cancer development.

Adult↗