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Biomedical subjects

H J Woo

Publications and source records attributed to H J Woo.

35 records · Page 2Linked to original sources
PubMed1999

Pylephlebitis associated with appendicitis.

Pylephlebitis usually occurs secondary to infection in the region drained by the portal venous system. A most common antesecent focus of infection is diverticulitis and the most common blood isolate is E. coli (54%), followed by Proteus mirabilis (23%). Overall mortality is 32% and most of the patients who had died had severe sepsis prior to the initiation of antibiotic therapy. We describe a case of pylephlebitis which had appendicitis and consequent septic thrombosis of the portal vein and its branches, with dissemination of infection to the liver. The patient had recovered due to timely antibiotic treatment alone and resulted in complete resolution. Early diagnosis and treatment are basic to a favorable clinical course.

Adult↗
PubMed1998

Heterogeneous HBV mutants coexist in Korean hepatitis B patients.

Although many hepatitis B virus (HBV) mutants have been found in all open reading frames since the precore defective mutant was initially reported, systematic investigations of diverse HBV mutant populations in hepatitis B patients have not been performed. Therefore, we examined whether heterogeneous mutant populations simultaneously exist in Korean hepatitis B patients. In order to detect hepatitis B virus mutants, we amplified a conserved core region and a surface antigen region of HBV DNA by PCR from sera of 27 Korean chronic hepatitis B patients, and then performed single strand conformational polymorphism analysis followed by DNA sequencing analysis. The results showed that heterogeneous HBV mutants in both regions were present in a single as well as in various hepatitis B patients. Sequence analysis revealed a defective interfering particle with missense mutation in the core region. We also found that two subtypes of adr and adw coexisted in a single patient. In addition, a point mutation causing a stop codon in the surface antigen region was observed. We are further analyzing the clinical implications of HBV mutants to identify their roles in the pathogenesis of chronic hepatic disorders induced by HBV.

Adult↗
PubMed1998

307-bp fragment in HOXA7 upstream sequence is sufficient for anterior boundary formation.

The HOX genes are expressed in a positionally and temporally restricted manner involving anteroposterior axial pattern formation during early embryogenesis. Previously, we studied the sequence and function of an upstream regulatory region of the human HOXA7 gene. To identify a critical cis-acting element, a deletion analysis was performed along the human control region (HCR) (about 1.1 kb), which was sufficient for setting the anterior boundary of expression in transgenic mice. We demonstrated that a 307-bp control region contains a cis-acting element(s) specifying an anterior boundary as well as a dorsal-ventral restriction in the neural tube at day 12.5 postconception (p.c.). The distinct anterior limit of expression was noted at the level of C7/T1 in the neural tube and spinal ganglia. In addition, our deletion experiments revealed that the HCR consisted of several cis-acting elements which were individually capable of driving regionally restricted expression patterns in the neural tube and limb buds.

Animals↗
PubMed1997

Primers determine the sensitivity of PCR-mediated hepatitis B virus DNA detection and pretreatment of PCR mixture with 8-methoxypsoralen eliminates false-positive results.

Most methods for the diagnosis of hepatitis B virus (HBV) infection largely depend on viral DNA detection by polymerase chain reaction (PCR) or radioimmunological assay of viral antigens or antibodies. The quality assurance program recently established in Europe reported that PCR-mediated HBV DNA detection methods used in many laboratories produced a high rate of false-positive and false-negative results. Thus, we attempted to improve the conditions of current PCR methods for detection of HBV DNA. In the present study, we applied a recently developed method of releasing HBV DNA from virion by NaOH treatment of patient serum. Using four different primer sets specific to the HBV core region, we found that the sensitivity of first-round PCR can be improved by more than two orders of magnitude depending on the primers. The second round of PCR using nested primers was sensitive enough to detect up to 10(-6) pg of the HBV DNA, which is equivalent to approximately 3 copies of the HBV genome. Among the approximately 800 HBV-infected patient sera investigated in our laboratory, more than 60% of the tested samples gave positive results in the first-round PCR. The rate of positive results obtained using our experimental conditions is very high in comparison with other reports. The reamplification of the first-round PCR reaction mixture with the nested primers produced practically 100% positive results. For diagnosis of HBV infection, we routinely used 1 microliter of patient serum, which was found to be optimum in our laboratory. Surprisingly, from 20% of our positive results, even serum diluted to 1/100 (0.01 microliter) produced a stronger signal than 1 microliter. This observation suggests that direct PCR amplification of HBV DNA released from serum by NaOH treatment has to be compensated by other DNA detection methods for correct quantitation. In order to eliminate the false positive signal resulting from the carry-over due to massive screening of a large number of samples, PCR reaction mixture containing 8-methoxypsoralen was exposed to ultraviolet light prior to thermal cycle amplification. This exercise did not decrease the sensitivity of the detection method, but almost completely removed the false positive results caused by contaminated templates. We are in the process of improving PCR-mediated HBV DNA detection methods to attain more reliable and easily applicable methods.

Base Sequence↗
PubMed1991

Carbohydrate-binding protein 35 (Mac-2), a laminin-binding lectin, forms functional dimers using cysteine 186.

Carbohydrate-binding protein 35 (CBP35), also known as the macrophage surface antigen Mac-2, is a lactosamine-specific lectin whose extracellular properties include the ability to agglutinate cells and to bind avidly to the basement membrane glycoprotein laminin. Although these and other properties would be facilitated by dimerization of this lectin, previous studies have argued against multimeric forms of this protein. We report here that macrophage CBP35, purified by laminin affinity chromatography, exists as several distinct species (Mr 35,000, 67,000, and 80,000) when analyzed under non-reducing conditions. This unexpected finding prompted us to study the biochemistry of multimerization using recombinant CBP35 (rCBP35). rCBP35 expressed in Escherichia coli forms disulfide-linked homodimers (Mr 67,000). The dimeric form of CBP35 binds to laminin with higher affinity than does monomer and by a lactosamine-dependent mechanism. Site-directed mutagenesis indicated that cysteine 186, the single cysteine residue in CBP35, is required for dimerization. These results raise the possibility that homo- and heterodimeric forms of CBP35 contribute to its postulated functions in cell-matrix interactions and growth regulation.

Amino Acid Sequence↗
PubMed1991

Carbohydrate-binding protein 35 is the major cell-surface laminin-binding protein in colon carcinoma.

The interaction of tumor cells with laminin is thought to be critical in invasion and metastasis. We found that an endogenous lectin, carbohydrate-binding protein 35 (CBP-35), is the major laminin-binding protein on human colon carcinoma cells and that its surface expression suggests involvement in metastasis. We identified CBP-35 by laminin-affinity chromatography and immunoblotting. Surface expression of CBP-35 on eight human colon carcinoma cell lines was compared by flow cytometry. Poorly differentiated cell lines and DLD-2, a signet-ring carcinoma cell line, expressed more surface CBP-35 than well-differentiated cell lines. Poorly differentiated cell lines and DLD-2 are characterized as aggressive cell lines because they adhere to and invade through reconstituted basement membrane significantly better than well-differentiated cell lines. These data suggest that CBP-35 is involved in tumor cell-basement membrane interactions and that an increase in CBP-35 surface expression may facilitate metastatic potential of colon carcinoma cells.

Antigens, Differentiation↗
PubMed1990

The major non-integrin laminin binding protein of macrophages is identical to carbohydrate binding protein 35 (Mac-2).

Current data indicate that cell adhesion to laminin, the major basement membrane glycoprotein, is mediated by specific integrins, a family of adhesion receptors. In addition, most cell types express a complement of high affinity non-integrin laminin binding proteins (LBPs). Despite considerable effort, the function of these LBPs has not been elucidated. We report here that the major non-integrin LBP of murine macrophages exhibits an Mr of 35,000 and is expressed on the cell surface. Protein microsequencing data revealed that this protein is identical to carbohydrate binding protein 35. This murine galactose-specific lectin is the macrophage antigen Mac-2. Thus, these data suggest that the non-integrin LBPs may contribute to laminin adhesion by a mechanism involving protein-carbohydrate interactions.

Amino Acid Sequence↗
PubMed1988

A human macrophage hybridoma producing a cytotoxic factor distinct from TNF, LT, and IL-1.

A stable human macrophage hybridoma was established by somatic cell fusion between human peripheral blood monocyte-derived macrophages and an 8-azaguanine resistant clone of a human histiocytic lymphoma cell line U-937 (clone U-937-F9). The hybrid cell line (F9P) exhibited typical macrophage-like morphology and had 30 more chromosomes than U-937-F9 cells. Its macrophage characteristics were confirmed by the manifestation of intracellular nonspecific esterase, the detection of Mo-2 and LEU-M3 antigens on the cell surface, and the demonstration of phagocytic activity. Furthermore, when stimulated with lipopolysaccharide (LPS), this cell line could secrete a considerable amount of a cytotoxic factor (CTF). Distinct from the hybrid cell line, the parental U-937-F9 cells expressed neither Mo-2 nor LEU-M3 antigens on the cell surface, did not show phagocytic activity, and their culture supernatants did not show cytotoxic activity even after LPS stimulation. The activity of CTF in the culture supernatant of the LPS-stimulated hybrid cells could not be neutralized with anti-tumor necrosis factor, anti-interleukin-1, or anti-lymphotoxin antibodies. The CTF had a relative molecular mass of 45-60 x 10(3) daltons as determined by gel filtration on a column of Superose 12, and an isoelectric point of 5.1. The cytotoxic activity was also induced when the hybrid cells were stimulated with the concentrated supernatants of a human T-cell hybridoma containing macrophage activating factor for cytotoxicity or with LP3 tumor cells which were used as target cells.

Antibodies↗
PubMed1988

Functional deficiencies of spleen dendritic cells in autoimmune MRL/lpr mice.

We investigated functional aspects of splenic dendritic cells (DC) obtained from MRL/MpJ-lpr/lpr (MRL/l) mice, and their normal counterparts, MRL/MpJ-+/+ (MRL/+) mice. In vitro antigen-presenting activity of DC obtained from MRL/l mice was impaired compared with that of DC from MRL/+ mice. Another major functional aspect of DC, i.e., stimulator cell activity in the allogeneic mixed lymphocyte reaction (MLR), was also found to be impaired in MRL/l mice. MRL/l mice and MRL/+ mice were also examined for co-operation between macrophages (M luminal diameter) and DC. We found peritoneal resident M luminal diameter obtained not only from MRL/+ mice but also from MRL/l mice released a soluble factor which enhanced the activity of DC from the respective mice. Furthermore, DC from both MRL/l and MRL/+ mice responded to the culture supernatant of a mouse macrophage hybridoma clone, S44, which releases a factor that enhances the antigen-presenting activity of DC, and their activity as stimulator cells in the allogeneic MLR was enhanced. However, the degree of enhancement was less in MRL/l mice than in MRL/+ mice.

Animals↗
PubMed1988

Homologous human macrophage hybridomas that produce a novel cytotoxic factor in their culture supernatants.

Homologous human macrophage hybridoma cell lines were obtained by somatic cell fusion between peripheral blood monocyte-derived macrophages and a subclone of the myelomonocytic cell line, U937-F9. The hybridoma cell lines grown in vitro for more than a year were confirmed by manifestations of phagocytosis, adherence, nonspecific esterase, acid phosphatase, chromosome numbers and other cell surface antigens. Cell surface antigens on hybridomas were detected by flow cytometry analysis with monoclonal antibodies. With interclonal differences, a typical phenotype of hybridoma cells was CDw14+, OKM5+, Mac-1+ (equivalent to OKM1 and Mol), OKT9+, HLA-DR- and CD20+. After stimulation with lipopolysaccharide and calcium ionophore A23187, culture supernatants of clones c18A and c29A showed cytotoxic activity against human melanoma A375 Met-Mix and other cell lines which were resistant to the tumor necrosis factor, lymphotoxin and interleukin 1. This cytotoxic factor was found to be distinct from the tumor necrosis factor, lymphotoxin and interleukin 1 using the anti-tumor necrosis factor, anti-lymphotoxin and anti-interleukin 1 antisera.

Antibodies, Monoclonal↗
PubMed1988

Dendritic cell activating factor produced by mouse macrophage hybridoma.

A mouse macrophage (M phi) hybridoma which produces a soluble factor responsible for the cooperation between M phi and spleen dendritic cells (DC) was constructed. The antigen-presenting activity and the stimulator cell activity in the allogeneic or syngeneic mixed leukocyte reaction of DC were significantly augmented when DC were incubated with the culture supernatant of the hybridoma treated with various stimulants including latex beads. The monokine present in the culture supernatant of the hybridoma, called dendritic cell-activating factor (DCAF), augmented the production of lymphocyte-activating factor by DC while Ia expression of DCAF-treated DC was not altered. DCAF had no effect on the antigen-presenting activity of peritoneal resident M phi or B cell blasts while the antigen-presenting activity of spleen M phi was enhanced, but the degree of the enhancement was much less than that of spleen DC. DCAF was found to have the following properties: its pI value is between pH 4 and 5; it is stable at pH 2 to 10; and it loses its activity on incubation at 75 C for 30 min. When the culture supernatant of the hybridoma stimulated with latex beads was subjected to gel filtration, the DCAF activity was detected in the 20 Kd to 25 Kd, 30 Kd to 40 Kd, and 50 Kd to 60 Kd molecular weight regions. The 30 Kd to 40 Kd fraction, which is the major peak fraction, was further purified by ion-exchange chromatography followed by gel-filtration chromatography. When each fraction was subjected to SDS-PAGE, a 30 Kd band corresponding to the DCAF activity was observed and DCAF was purified to about 90% purity.

Animals↗
PubMed1986

The production of a cytotoxic factor by mouse peritoneal macrophages and macrophage hybridomas treated with various stimulating agents.

Murine peritoneal macrophages elicited with a streptococcal preparation, OK-432, produced as much of a cytotoxic factor after stimulation with lipopolysaccharide (LPS) as BCG-elicited macrophages did. Proteose peptone-elicited macrophages produced a very small amount, if any, of the factor, and resident peritoneal macrophages did not release it at all even after LPS-stimulation. A newly established macrophage hybridoma, D/O-3.3, produced the factor after LPS-stimulation, but another hybridoma, D/O-3.2, did not. Experiments using these peritoneal macrophages and macrophage hybridomas demonstrated that macrophages can be divided into three subpopulations with regard to stages of activation for production of the cytotoxic factor. The first is fully activated macrophages which produce the factor after stimulation with LPS or MAF-C alone, the second is partially activated macrophages which produce the factor only after stimulation with a combination of recombinant interferon-gamma (rIFN-gamma) and LPS or rIFN-gamma and macrophage activating factor for cytotoxicity (MAF-C), and the third is nonactivated macrophages which cannot produce the factor at all.

Animals↗
PubMed1985

Mouse macrophage hybridomas secreting a cytotoxic factor and interleukin 1.

Stable mouse macrophage hybridomas were produced by somatic cell fusion between proteose peptone-elicited peritoneal macrophages and NS-1 myeloma cells. Three cloned hybrid cell lines, designated as N/P-5-3, -6-2, and -7-1, exhibited typical macrophage-like morphology. Moreover, their macrophage characteristics were confirmed by the manifestation of intracellular nonspecific esterase, the detection of Mac-1 antigens and Fc-receptors on the cell surface, and the demonstration of phagocytic and antigen-presenting activities. Furthermore, these cell lines, stimulated with LPS, secreted considerable amounts of a cytotoxic factor and interleukin 1. Cultured cells of various tumor cell lines were sensitive to the cytotoxic factor, but normal thymocytes, spleen cells, and liver cells were not killed by the factor.

Animals↗
PubMed1985

Purification and characterization of a cytotoxic factor produced by a mouse macrophage hybridoma.

A mouse macrophage cytotoxic factor was purified to homogeneity from the serum-free culture supernatant of a mouse macrophage hybridoma clone, N/P-7-1, stimulated with lipopolysaccharide by gel filtration, affinity chromatography, anion-exchange chromatography, and polyacrylamide gel electrophoresis. The purified material was judged to be homogeneous as to the criteria of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and has a relative molecular mass of 17,500, as determined by SDS-PAGE, or 55,000, as determined by gel filtration on columns of both Sephacryl S-200 and TSK G3000SW. It has an isoelectric point of 5.0, and is trypsin sensitive, stable at 56 degrees C and labile at pH less than 6. The cytotoxic activity of the purified factor could not be inhibited by various sugars and lectins. The production of the factor from N/P-7-1 triggered by macrophage-activating factor for cytotoxicity, but not by mouse recombinant gamma-interferon. The factor should be synthesized after lipopolysaccharide stimulation because treatment of N/P-7-1 cells with a metabolic inhibitor, emetine or actinomycin D, prevents the production.

Animals↗
PubMedDate not supplied

An environmental research on trace elements in freshwater fish by neutron activation analysis.

For a case study of environmental contamination, radiochemical activation analysis has been applied to the crucians collected in the Han River. Sixteen trace elements (Hg, Cd, As, Br, Cu, Na, K, Se, Cr, Hf, Rb, Fe, Zn, Co, La, and Cs) were separated into three groups using distillation and diethyldithiocarbamate extraction methods, and their contents were determined by a single comparator method. Compared with the values 15 years ago, the values for mercury and cadmium have been drastically decreased at the middle and lower part of the river, but no typical change is found in other elements.

Animals↗
PubMedDate not supplied

Immunohistochemical detection of galectin-3 in canine gastric carcinomas.

Galectin-3 was detected immunohistochemically in nine canine gastric carcinomas. In normal gastric tissue adjacent to the neoplasms, the gastric epithelial cells showed faint immunolabelling for galectin-3, but in all the tumours the neoplastic cells showed moderate to strong immunolabelling. Galectin-3 was localized in the cytoplasm of the normal mucosal cells, whereas it was found in both the cytoplasm and the nucleus of the neoplastic cells. Positive cells typically exhibited dark brown coloration of the nucleus or cytoplasm, without background labelling. The results suggest that galactin-3 has a pathophysiological role in canine gastric carcinoma.

Animals↗