Biomedical subjects

Y T Kim

Publications and source records attributed to Y T Kim.

At least 73 records · Page 4Linked to original sources

PubMed1999

A case of primary transitional cell carcinoma of the fallopian tube.

The primary carcinoma of the fallopian tube is the rarest of all gynecologic malignancies and histologically most of them are adenocarcinomas. Primary transitional cell carcinomas are extremely rare in the fallopian tube. A 63-year-old postmenopausal woman presenting with lower abdominal pain was found to have a left adnexal mass. Exploratory laparotomy revealed a mass arising from the fallopian tube with the histologic features of transitional cell carcinoma. Light and electron microscopic studies supported the notion of transitional cell carcinoma. The tumor was extended to the muscle layer and confined to the left fallopian tube without metastasis. The patient received 3 courses of systemic cisplatin-based chemotherapy and has been well with no evidence of recurrence until August, 1998.

Abdominal Pain↗

PubMed1999

A precipitation reaction found in patients with hepatitis C as a marker for the purification of virus-like particles.

Even after the molecular cloning of the hepatitis C virus (HCV), an HCV-specific precipitation reaction has not yet been identified. We attempted to develop a precipitation system exclusively for anti-HCV-positive sera as a first step in finding an HCV-specific antigen and HCV-associated particles. In some patients being in a final stage of different liver diseases, we found sera (179/132,761; designated 'a-CK') which specifically precipitated with anti-HCV- and HCV-RNA-positive sera (designated 'CK'). When CK-positive sera were searched for in patients with various liver diseases using standard a-CK-positive plasma, CK was detected in 420 (57.9%) of 726 anti-HCV-positive sera and in none of the 1,630 anti-HCV-negative ones. The nature of CK and a-CK has not been fully clarified yet; CK demonstrated inter-betagamma mobility, whereas a-CK showed beta-globulin mobility; CK was not detected in cryoprecipitate, but HCV RNA was present in precipitates of CK-positive plasma incubated with one that was a-CK positive. Transmission electron microscopy revealed two size ranges of particles in the precipitate of CK- and a-CK-positive plasmas, 23-38 nm and 48-65 nm. We have found a novel precipitation system which is exclusive to anti-HCV-positive sera and which specifically precipitates an HCV-RNA-containing serum fraction and particles. This system can be useful for the purification and characterization of the circulating particles. Furthermore, it may be a new approach to the nature of HCV-RNA-carrying material.

Centrifugation↗

PubMed1999

Correlation between EGFR and c-erbB-2 oncoprotein status and response to neoadjuvant chemotherapy in cervical carcinoma.

Neoadjuvant chemotherapy prior to definitive radical surgery or radiotherapy may be effective in reducing tumor volume or clinical stage and may even enhance pelvic control and survival. However, there are significant limitations to the use of neoadjuvant therapy in the non-responder group. They include delayed total treatment course, the presence of drug resistant clones which result in accelerated tumor growth, and limited bone marrow reserve for subsequent definitive therapy. Thus, there is a need to identify parameters providing a more precise indication of the response to neoadjuvant chemotherapy in patients with invasive cervical cancer. From Jan. 1995 to Jan. 1996, neoadjuvant chemotherapy with 3 courses of cisplatin and vincristine was used in 32 patients with invasive cervical cancer (FIGO stage Ib to IIIb; tumor size greater than 2 cm). Prior to chemotherapy, quantitative tissue levels of epidermal growth factor receptor (EGFR) and c-erbB-2 oncogene protein were measured by using an enzyme-linked immunosorbent assay (ELISA). Tumor size was estimated before and after chemotherapy. Relations between oncoproteins and reductions of tumor size were evaluated. Tumor size prior to neoadjuvant chemotherapy did not show any correlation with either the concentrations of EGFR or c-erbB-2 oncoprotein. As well, the tumor reduction index did not manifest any correlation with EGFR, it did had an inverse linear correlation with the c-erbB-2 oncoprotein levels (Rs = -0.71, P < 0.05). The results of this study suggest that c-erbB-2 oncoprotein is associated with a reduced response to neoadjuvant chemotherapy in primary treatment of invasive cervical cancer and may be useful in directing therapeutic approaches.

Adult↗

PubMed1999

Endoscopic management of uterine myoma.

This study was undertaken to evaluate the various gynecologic endoscopic surgical techniques including resectoscopic myomectomy, laparoscopic myomectomy, and laparoscopy assisted vaginal hysterectomy (LAVH) used in the treatment of uterine myomas. The medical records of 136 cases of uterine myomas treated using one or more of the gynecologic endoscopic surgical techniques in the Department of Obstetrics and Gynecology at Yonsei University were retrospectively reviewed from March 1997 to September 1998. Of the 136 cases reviewed, there were 40 submucosal myomas and 96 intramural and subserosal myomas. For statistical analysis, Student's t-test was used. Submucosal myomectomy using the resectosope was performed in 35 cases (mean age: 39 +/- 1.5 years), laparoscopic myomecotmy in 35 cases (mean age: 36 +/- 1.9 years), and LAVH in 66 cases (mean age: 42 +/- 1.1 years). In cases of huge myomas, the GnRH agonist was used prior to surgery, and in cases of heavy uterine bleeding, angioblock of the uterine artery was undertaken before the endoscopic procedures. The mean operating time was significantly shorter in resectoscopic myomectomy (41 +/- 12 min), followed by laparoscopic myomectomy (85.0 +/- 10.3 min) and LAVH (123 +/- 5.3 min). The mean hospital stay for resectoscopic myomectomy, laparoscopic myomectomy, and LAVH was 1.9 +/- 0.5, 2.5 +/- 0.5, and 3.4 +/- 0.8 days (p < 0.001), respectively. There were 3 cases of complications including pulmonary edema and uterine perforation in the resectoscopic myomectomy group, and 4 cases of complications including bladder, ureter, and epigastric vessel injury in the LAVH group. In conclusion, the therapeutic effect of various gynecologic endoscopic surgical techniques can be maximized in terms of shorter operation time, shorter hospital stay, faster recovery, and less blood loss by the appropriate management of uterine myoma in well-chosen patients.

Adult↗

PubMed1999

Loss of heterozygosity in dysplasia and carcinoma of the gallbladder.

The loss or inactivation of genes at specific chromosomal loci is one of the important mechanisms during the tumor development in humans. To investigate the role of genetic alterations in the carcinogenesis of gallbladder carcinoma, 32 carcinoma cases and 11 dysplasia cases of gallbladder were analyzed for loss of heterozygosity (LOH) and microsatellite instability (MI) on chromosomal regions 3p, 5q, 8p, 9p, 13q, 17p, and 18q with 17 microsatellite markers. Loss of one allele was identified on chromosomes 5q (55%) and 17p (40%) in dysplasias and on chromosomes 3p (52%), 5q (66%), 9p (52%), and 17p (58%) in carcinomas. LOH on chromosomes 13q and 18q was frequent only in advanced stage (III and IV) carcinomas (40% and 31%, respectively). LOH on chromosome 17p was correlated with intranuclear p53 accumulation. LOH on multiple chromosomes was more frequent in advanced carcinomas with metastasis than in cases without metastasis (P < .05). A widespread MI was observed in only one case of carcinoma. We conclude that LOH on 5q is an early change of carcinogenesis in gallbladder and that LOH on 3p and 9p is related to the progression of gallbladder carcinoma LOH on 13q and 18q is likely to be a late event. LOH on 17p occurs not only in dysplasia but also increases during the subsequent stages. Accumulation of LOH may be associated with carcinogenesis of the gallbladder, but the role of MI may not be significant.

Adult↗

PubMed1998

c-erbB-2 oncoprotein assay in ovarian carcinoma and its clinical correlation with prognostic factors.

Overexpression of the c-erbB-2 oncoprotein has been detected in human adenocarcinoma of the breast, cervix and salivary gland, in all of which an association between the overexpression of the c-erbB-2 and a poor prognosis of the disease has been reported. However, the prognostic role of c-erbB-2 oncoprotein in ovarian carcinoma remains controversial. We measured c-erbB-2 oncoprotein with an enzyme-linked immunosorbent assay (ELISA). Patients with invasive ovarian cancer were found to have significantly higher median c-erbB-2 oncoprotein expression than patients with either benign ovarian cyst (P = 0.002) or control groups (P = 0.001). Overexpression of c-erbB-2 oncoprotein was found in seven (21.9%) of 32 epithelial ovarian cancers. Our results suggest that quantitative analysis of c-erbB-2 oncoprotein may be used to define the prognostic significance of ovarian carcinoma.

Adult↗

PubMed1998

The cDNA cloning and ontogeny of mouse alpha-synuclein.

Alpha-synuclein has been implicated in the pathogenesis of Parkinson's disease. To investigate the role of alpha-synuclein in the brain, the cDNA clone encoding the mouse cognate of the human alpha-synuclein was isolated from a mouse brain cDNA library. The open reading frame coded for 140 amino acids that share 95% identity with human alpha-synuclein. Northern blot analysis showed that alpha-synuclein mRNA was primarily expressed in brain and spleen of adult mouse. In situ hybridization histochemistry revealed the highest expression of alpha-synuclein mRNA in the hippocampal formation and neocortex of the adult mouse. alpha-Synuclein mRNA expression in the brain was first observed in the hippocampus and neocortex on postnatal day 1. Levels of alpha-synuclein mRNA in these forebrain areas were nearly maximal at postnatal day 7 and remained relatively high until the adult stage. alpha-Synuclein mRNA was expressed in the liver transiently during embryogenesis.

Amino Acid Sequence↗

PubMed1998

Underexpression of cyclin-dependent kinase (CDK) inhibitors in cervical carcinoma.

Recent studies have revealed a new family of tumor suppressor genes that directly implicate aberrant cell cycle regulation in tumorigenesis. The general function of these gene products is that they prevent cell cycle progression by directly interfering with cyclin/cyclin-dependent kinase (CDK) activation. The importance of these genes is that they are potent inhibitors of CDK. Among these cell cycle inhibitors, p21(WAF1/CIP1) and p16 have been thoroughly studied. However, the role of p21(WAF1/CIP1) and p16 in the tumorigenesis of the uterine cervix has been poorly defined. We used immunohistochemical techniques to study the expression of these cell cycle inhibitors in formalin-fixed, paraffin-embedded cervical tissue to explore the relationship between cyclin/CDK inhibitors and cervical carcinoma. Cervical tissues were analyzed from 46 patients with cervical carcinoma, 30 cases with cervical intraepithelial neoplasia (CIN) and 22 control cases who underwent hysterectomy due to benign gynecologic disease at Yonsei University College of Medicine. All CDK inhibitors were strongly expressed in the reverse cell hyperplasia and koilocytes, whereas they revealed significantly decreased expression in neoplastic tissues (P < 0.05). P16 revealed higher expressions in cases associated with human papillomavirus (HPV) (t test, P < 0.05) than in cases lacking any type of HPV. Our results were consistent with the concept that underexpression of CDK inhibitors may play an important role in neoplastic transformation in cervical carcinoma.

Adult↗

PubMed1998

Synthesis and properties of dextran-5-aminosalicylic acid ester as a potential colon-specific prodrug of 5-aminosalicylic acid.

Dextran-5-aminosalicylic acid ester (dextran-5-ASA) was synthesized as a colon-specific prodrug of 5-aminosalicylic acid (5-ASA) which is active against inflammatory bowel diseases. Chemical stability of dextran-5-ASA in the bath of pH 1.2 or 6.8 was investigated at 37 degrees C for 6 hrs, and 5-ASA was not released on such conditions. Depolymerization (%) of dextran-5-ASA by dextranase with the degree of substitution (DS) of 18, 23, or 30 was 92, 62 or 45 in 8 hrs respectively, but was not affected by the MW of dextran (9,000, 40,600, 80,200 or 580,000). Distribution of 5-ASA in dextran, determined by gel filtration chromatography, appeared to be relatively uniform. Incubation of dextran-5-ASA (DS 18) in cecal contents of rats released 20% (28 g) and 35% (49 g) of 5-ASA in 8 hrs and 24 hrs, respectively, but no 5-ASA was liberated from small intestinal contents.

Aminosalicylic Acids↗

PubMed1998

Formation, properties and antimicrobial activities of cotton xanthate-Cu(II)-homosulfamine complex.

To develop a cotton derivatives with prolonged antimicrobial activities, homosulfamine (Hs) was coupled to cotton xanthate (CX) via chelate bond in the presence of Cu(II) ion by one- and two-bath processes. In one-bath process, CX was treated with Cu(II)-Hs solution. In two-bath process, CX was treated with Cu(II) ion solution to produce CX-Cu(II) complex, which was isolated and treated in turn with Hs solution. Effects of concentration, Cu(II)/Hs ratio, and pH on the binding of Hs were investigated at 10 degrees C. In one-bath process, binding of Hs took place readily with optimum pH around 5-6. The amount of binding increased to give a maximum within 5 min and decreased slowly to establish an equilibrium within an hour. In two-bath process, binding of Hs was much lower than that of one-bath process. Release of Hs from CX-Cu(II)-Hs was investigated by batch and flow method. Antimicrobial activities of CX-Cu(II)-Hs were tested against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli and it showed prolonged activity compared to that of free Hs.

Anti-Bacterial Agents↗

PubMed1998

Identification of polypeptides associated with an enriched cytoskeleton-protein body fraction from developing rice endosperm.

Recent evidence has shown that the prolamine polysomes are attached not only to the endoplasmic reticulum membranes that bound the prolamine protein bodies (PBs) but also to cytoskeleton elements associated with this subcellular fraction. To learn more about the nature of the proteins that are associated with this supra-macromolecular complex, proteins extracted from an enriched cytoskeleton-PB fraction were resolved by two-dimensional polyacrylamide gel electrophoresis under non-equilibrium conditions and analyzed for their composition by immunological and biochemical methods. Immunoblot analysis indicated the presence of the cytoskeletal proteins, actin and tubulin, and the cytoskeletal-associated protein EF1 alpha in this fraction. Microsequencing of selected polypeptides revealed a diversity of protein sequences. In addition to contaminating storage proteins which are selectively solubilized by the isolation procedure, several ribosomal proteins and histone H3 were also identified. Some of the remaining polypeptides showed partial homology to protein sequences deposited in the database, several of which are cytoskeleton-associated proteins.

Amino Acid Sequence↗

PubMed1998

Primary ovarian failure caused by a solvent containing 2-bromopropane.

Sixteen Korean female laborers who had been exposed to a cleaning solvent composed mainly of 2-bromopropane developed primary ovarian failure. Histologic findings from these patients' ovaries were similar to those observed in ovarian failure caused by radiation or chemotherapy, i.e., reduced number and developmental arrest of primary follicles, interstitial fibrosis and hyalinization of blood vessels. We followed their clinical course for 2 years and found that two patients recovered normal ovarian function spontaneously: one became pregnant and delivered a normal full-term baby, and the other resumed regular menstrual periods with normal hormonal values. Our observations support the idea that the increasing prevalence of ovarian failure in recent years might be due to an increase in presently unidentified environmental toxic agents.

Adult↗

PubMed1998

Heterogeneity of IgE response to TDI-HSA conjugates by ELISA in toluene diisocyanate (TDI) -induced occupational asthma (OA) patients.

Toluene diisocyanate (TDI), a low molecular weight reactive chemical, is known to be a main cause of occupational asthma (OA) in Korea. Although it is thought that inhaled TDI may act as a hapten, the precise mechanisms of TDI-induced OA are unknown. In this study, TDI-human serum albumin (HSA) conjugates (5, 10, 20 and 30 min) were prepared in the range of 1.5 to 5.0 TDI mole/HSA mole. Specific binding of serum IgE to TDI-HSA (30 min) was observed using IgE ELISA as well as ELISA inhibition assay. Around 40% of TDI-induced OA patients were positive for serum specific IgE by ELISA. Degrees of serum IgE binding were different depending on which TDI-HSA conjugate was used as an antigen. Moreover, binding patterns were different depending on the individuals. Interestingly, higher binding of IgE to TDI-HSA (5 min) than to TDI-HSA (30 min) which was more highly substituted was observed in some patients. Probably new antigenic epitopes on carrier proteins were targets of the specific IgE. The results of this study indicated that IgE responses to TDI-HSA conjugates were heterogeneous in TDI-induced OA patients and self-proteins modified by reactive chemicals can become a major target antigen of IgE in certain cases.

Antibody Specificity↗

PubMed1997

Loss of FHIT expression in cervical carcinoma cell lines and primary tumors.

Allelic deletions involving the short arm of chromosome 3 (3p13-21.1) have been observed frequently in cervical carcinomas. Recently, a candidate tumor suppressor gene, FHIT (Fragile Histidine Triad), was cloned and mapped to this chromosomal region (3p14.2). Abnormal FHIT transcripts have been identified previously in a variety of tumor cell lines and primary carcinomas, although their significance and the molecular mechanisms underlying their origin remain incompletely defined. In addition, integration of human papillomavirus DNA has been identified at a fragile site (FRA3B) within the FHIT locus in cervical cancer. These observations motivated us to evaluate FHIT mRNA and protein expression in cervical cancer cell lines, primary cervical carcinomas, and normal tissues. Transcripts of the expected size and sequence were the predominant species identified by reverse transcription (RT)-PCR in cultured keratinocytes and all normal tissues evaluated. In contrast, aberrant FHIT transcripts were readily demonstrated in 6 of 7 cervical carcinoma cell lines and 17 of 25 (68%) primary cervical carcinomas. Northern blot analyses demonstrated reduced or absent FHIT expression in the cervical carcinoma cell lines, particularly those with aberrant RT-PCR products. Immunohistochemical analysis of Fhit expression in cervical tissues revealed strong immunoreactivity in nonneoplastic squamous and glandular cervical epithelium and marked reduction or loss of Fhit protein in 25 of 33 (76%) primary cervical carcinomas. In those cervical cancer cell lines and primary tumors with exclusively aberrant or absent FHIT transcripts by RT-PCR, Fhit protein expression was always markedly reduced or absent. The frequent alterations in FHIT expression in many cervical carcinomas, but not in normal tissues, suggest that FHIT gene alterations may play an important role in cervical tumorigenesis.

Acid Anhydride Hydrolases↗

PubMed1997

Recombinant brain 4-aminobutyrate aminotransferases overexpression, purification, and identification of Lys-330 at the active site.

4-Aminobutyrate aminotransferase (4-aminobutyrate: 2-oxoglutarate aminotransferase EC 2.6.1.19) is a key enzyme of the 4-aminobutyric acid shunt. It catalyzes the conversion of 4-aminobutyrate to succinic semialdehyde. In an effort to clarify the structure-function relationships of 4-aminobutyrate aminotransferase, we analyzed 4-aminobutyrate aminotransferase cDNA from pig brain. The inclusion bodies were formed when recombinant 4-aminobutyrate aminotransferase was overexpressed in Escherichia coli. The unfolded overproduced proteins, were purified by hydroxylapatite chromatography in the presence of urea and refolded by a sequential dialysis method. The renatured protein regained its catalytic activity. The lysyl residue at the 330 position of the amino-acid sequence serves as the anchoring site of the cofactor pyridoxal 5'-P. To verify the catalytic site of 4-aminobutyrate aminotransferase, lysine 330 was mutated to arginine by site-specific mutagenesis. Overexpression and purification of the mutated 4-aminobutyrate aminotransferase (K330R) were performed by the same method used the purification of wild-type 4-aminobutyrate aminotransferase. The purified and renatured K330R protein did not show the catalytic activity of wild type 4-aminobutyrate aminotransferase. Furthermore, the mutated protein did not show any absorption band over the spectral range of 320-460 nm characteristic of pyridoxal 5'-P covalently linked to the protein. From the results presented here, it is concluded that lysine 330 is essential for the catalytic function of the aminotransferase.

4-Aminobutyrate Transaminase↗

PubMed1997

Captopril modulates hormone receptor concentration and inhibits proliferation of human mammary ductal carcinoma cells in culture.

The present study evaluated the effect of the angiotensin converting enzyme (ACE) inhibitor captopril on estrogen (ER) and progesterone (PR) receptor concentration and on proliferation in two lines of human mammary ductal carcinoma cells in culture: T-47D (ER+/PR+) and Hs578T (ER-/PR-). The incorporation of [3H]thymidine, validated by cell count, served as an index of proliferation. Compared to control cells, T-47D cells incubated for 48 hrs in 1, 2, or 5 mM captopril (but not in 0.5 mM) exhibited a reduction in ER from 130 +/- 6 to 32 +/- 32 fmol/mg cytosolic protein, and an increase in PR from 1780 +/- 120 to 2740 +/- 400 fmol/ mg protein (p < 0.05). Western analysis confirmed these drug-induced changes in the concentration of immunoreactive receptor proteins. Captopril also induced the appearance of low but detectable PR in the Hs578T cells at concentrations as low as 50 microM. Captopril inhibited the incorporation of [3H]thymidine by both cell types during a 48 hr incubation, although Hs578T cells were 2-3 times more resistant than were T-47D cells. This cytostatic effect of captopril was not due to cytotoxicity as indicated by 51Cr release, and was not accompanied by significant changes in cell cycle distribution as determined by flow cytometry. The incorporation of [3H]uridine (RNA synthesis) and [14C]alanine (protein synthesis) also were inhibited by captopril, suggesting a general antimetabolic effect of the drug in the ductal carcinoma cells. These are novel actions of a common antihypertensive agent. In contrast, the nonthiol ACE inhibitor lisinopril, and penicillamine, a thiol compound with virtually no ACE inhibitory activity, had no effect on any of these endpoints.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1997

Purification and characterization of an endoglucanase from the marine rotifer, Brachionus plicatilis.

The marine rotifer, Brachionus plicatilis, is able to digest Chlorella efficiently, suggesting that the rotifer contains a powerful cellulolytic enzyme system. A multi-component cellulolytic complex, including endoglucanase (CM-cellulase), cellobiohydrolase and beta-glucosidase, was found in Brachionus plicatilis. Endoglucanase (endo-beta-1,4 glucanase) was purified to homogeneity from rotifer homogenates using a sequential chromatographic method. The purified enzyme exhibits a strong hydrolytic activity with carboxymethyl(CM)-cellulose. The optimum temperature and pH for the endoglucanase activity were 37 degrees C and 7.0, respectively. 80% of the CM-cellulase activity was retained in salt mixture that ranged from 150 to 500 mM NaCl equivalent. The purified protein was isolated with a molecular weight of approximately 62 kDa estimated by SDS-polyacrylamide gel electrophoresis.

Animals↗

PubMed1997

Purification and characterization of an extracellular metalloprotease from Pseudomonas fluorescens.

An extracellular metalloprotease was purified from the culture supernatant of Pseudomonas fluorescens strain KT1 to apparent homogeneity and shown to consist of a single polypeptide chain (M(r) 46,000-47,000). The enzyme was strongly inhibited by chelating agents such as EDTA and o-phenanthroline, and activated by certain detergents. Among the peptidyl 4-methylcoumaryl-7-amide (MCA) substrates examined, t-butyloxycarbonyl-Arg-Val-Arg-Arg-MCA was the best one. With this substrate, the enzyme exhibited a pH optimum of around pH 5.5 in the absence of Co2+ ions, whereas it showed two different pH optima (at pHs around 5.5 and 8-9) in the presence of Co2+ ions due to remarkable activation by Co2+ ions in the alkaline pH range. On the other hand, a single broad pH optimum of around 6 to 8 was obtained with some peptides in both the presence and absence of Co2+ ions, and no activation by Co2+ was observed. The enzyme showed trypsin-like specificity, preferentially cleaving certain arginyl peptide bonds, and hydrolyzed the basic protein, histone, most rapidly among various proteins examined. Partial amino acid sequence analysis revealed that the enzyme is highly homologous with proteases of the serralysin family, a group of zinc metalloproteases.

Amino Acid Sequence↗