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A Ooi

Publications and source records attributed to A Ooi.

At least 19 recordsLinked to original sources
PubMed2006

Differential expression and pathological significance of autocrine motility factor/glucose-6-phosphate isomerase expression in human lung carcinomas.

To clarify the involvement of autocrine motility factor (AMF) in the phenotype and biological profiles of human lung carcinomas, we analysed protein and mRNA expression in a total of 180 cases. Immunohistochemistry revealed positive staining in 67.2%, with the highest frequency in squamous cell carcinoma (SCC; 90.8%) and the lowest in small cell carcinoma (SmCC; 27.8%). In SCC, the staining frequency and intensity correlated with the degree of morphological differentiation. Generally, the expression levels in immunoblotting analysis corresponded well with immunohistochemical positivity. However, there was less agreement between protein and mRNA levels: in SmCC and large cell carcinomas (LCCs), mRNA showed higher, but protein showed lower expression. Among non-small cell lung carcinomas (NSCLCs), AMF protein levels correlated inversely with tumour size, but tumours exhibiting lymph node metastasis showed higher mRNA expression. In cultured lung carcinoma cells which comprised all histological subtypes, AMF was detected in the lysates of all ten cell lines. Secreted AMF protein was detected in the conditioned media from six cell lines, most of which were SmCC or LCC. Thus, a particular subset of lung carcinomas secrete AMF, which may promote cell motility via autocrine stimulation through its cognate receptor and cause the biological aggressiveness seen in SmCC and LCC. Moreover, treatment by proteasome inhibitors resulted in increased cellular AMF in five cell lines, suggesting that intracellular AMF levels are regulated by both secretion and proteasome-dependent degradation. In conclusion, AMF was detected in a major proportion of lung carcinomas, and may play a part not only in proliferation and/or progression of the tumours, but also, possibly, in the differentiation of SCC. Furthermore, higher mRNA expression may be related to the high metastatic potential of NSCLC and increased protein secretion, leading to a more aggressive phenotype, such as the invasiveness of SmCC and LCC.

Adenocarcinoma↗
PubMed2005

Frequencies of HER-2/neu expression and gene amplification in patients with oesophageal squamous cell carcinoma.

The utilisation of antitumour T cells induced by cancer vaccination with HER-2 peptides or antibodies (Herceptin) against HER-2, as immunotherapy for oesophageal cancer, is a novel and attractive approach. It is important to clarify the frequencies of HER-2 expression and gene amplification in patients with oesophageal squamous cell carcinoma (SCC) and to evaluate the relationship between HER-2 status and HLA haplotype, since the candidates for HER-2 peptide-based vaccination are restricted to a certain HLA haplotype. We determined the frequency of HER-2 expression using the HercepTest for immunohistochemistry and HER-2 gene amplification by fluorescence in situ hybridisation (FISH) assay in oesophageal SCC (n=66). HER-2-positive tumours (1+/2+/3+) analysed by a HercepTest were observed in 30.3% of all the patients and HER-2 gene amplification evaluated by FISH was observed in 11.0% of all the patients, in which all HercepTest (3+) tumours were found to have gene amplification and three of six moderately positive (2+) tumours showed gene amplification. Furthermore, HER-2-positive cells were present more diffusely and were larger within each tumour in the patients who were HercepTest 3+ than those who were HercepTest 1+. Moreover, the survival rate in HER-2-positive group was significantly worse than that in HER-2-negative group. Also, the survival rate in the patients with HER-2 gene amplification was significantly worse than that without HER-2 gene amplification. In addition, oesophageal SCC patients with both HLA-A24-positive and HER-2-positive tumours (1+/2+/3+) accounted for 26% of these cases, and both HLA-A2- and HER-2-positive tumours accounted for 18% of them.

Aged↗
PubMed2004

Screening for novel ENU-induced rhythm, entrainment and activity mutants.

Chemical mutagenesis has provided an opportunity to develop and expand the repertoire of behavioural mutants for gene function studies. With this in mind, we have established a screen in mice for mutations affecting circadian rhythms, entrainment to light and other wheel-running parameters. The screen consists of an assessment of mouse wheel-running activity in a 12:12 h light/dark cycle for 7-10 days followed by assessment in constant darkness for up to 20 days. Responses to light are assessed using two protocols; a 15 minute light pulse given at circadian time 16 on the tenth day in constant darkness and an additional 12 h of light upon transition from light/dark conditions to constant darkness. To date, approximately 1300 progeny of chemically mutagenised mice have been screened. Computer-aided assessment of wheel-running parameters has helped in identifying abnormal phenotypes in approximately 5% of all animals screened. Inheritance testing of mice with abnormal phenotypes has confirmed the number of robustly inherited mutant phenotypes to be 1% of the total screened. Confirmed mutants including those affecting free-running period, light-responsiveness and wheel-running endurance have been identified. Thus far, low-resolution map positions have been established for four mutants by completing genome scans in backcross progeny. Mutant loci do not correspond with those previously associated with wheel-running behaviour. This result confirms that phenotype-driven approaches such as this should continue to provide material for mammalian gene function studies.

Animals↗
PubMed2003

Boxer's pericardium.

A 65-year-old retired professional boxer presented with progressively worsening shortness of breath, peripheral oedema and mild abdominal swelling over a period of 6 months. His only past medical history was hypertension. Subsequent investigations revealed chylous ascites, pericardial constriction and bilateral chylothorax. He had uneventful pericardectomy, and post-operatively the chylothorax resolved only after administration of octreotide for 10 days. The histopathological features of fibrosis, haemosiderin deposition in the pericardium and abundant haemosiderin-laden macrophages are consistent with chronic resolving haemopericardium. These findings suggested that the cause of pericardial constriction was repeated chest trauma from boxing.

Aged↗
PubMed2001

Protein overexpression and gene amplification of c-erb B-2 in pulmonary carcinomas: a comparative immunohistochemical and fluorescence in situ hybridization study.

Amplification of the c-er bB-2 gene (located on 17q11.2--12) is accompanied by overexpression of its cell surface receptor product, p185(ERBB2). In pulmonary carcinomas, however, there has been disagreement between the reported frequencies of gene amplification and overexpression. To clarify their relationship, the correlation between the cellular expression of p185(ERBB2) and the level of c-erb B-2 gene amplification was studied. A total of 195 pulmonary carcinomas (182 primary and 13 metastatic) were examined immunohistochemically using a polyclonal antibody, which recognizes the internal domain of the human c-erb B-2 protein, and positive tumors were further examined for the gene amplification by dual-color fluorescence in situ hybridization using probes for centromere 17 and 17q11.2--12. By immunohistochemistry, distinct membrane staining was found in an adenocarcinoma, a large cell carcinoma and a metastatic carcinoma from the breast, and cytoplasmic and/or faint membranous staining was observed in 23 non-small cell lung carcinomas. It was in the two primaries and the metastatic carcinoma that more than 8-fold amplification of c-erb B-2 was found by fluorescence in situ hybridization. Especially, in the two primary carcinomas, tumor cells had amplified genes with the signals forming one or two clusters, indicating that the amplified gene was present in homogeneously staining regions. Among the 23 tumors, three tumors showed low-level amplification (less than 3-fold), which was differentiated from polysomy 17 found in the other two. In the 30 non-small cell lung carcinomas selected at random from 151 with negative immunostaining, there were five trisomy 17, but no tumors with the gene amplification. This suggests that although c-erb B-2 amplification in pulmonary carcinoma is rare, it occurs in the form of a homogeneously staining region and is thought to control the overexpression of the protein in the cell membrane. New adjuvant therapy using a humanized antibody to the oncoprotein may be beneficial to patients with these tumors.

Carcinoma, Non-Small-Cell Lung↗
PubMed2001

Numerical modelling of flow and heat transfer in the rotating disc cavities of a turboprop engine.

A numerical analysis of the flow and heat transfer in the cavity between two co-rotating discs with axial inlet and radial outflow of fluid, a configuration common in gas turbine engines, is described. The results are compared with the experimental data of Northrop and Owen. The effectiveness of the k-epsilon turbulence model with the two-layer zonal model for near-wall treatment of Chen and Patel is tested for this type of flow. Using three-dimensional models it is shown that modelling discrete holes at the outlet as opposed to a continuous slot, which is the approximation inherent in the two-dimensional axisymmetric model, has little effect on the predicted Nusselt number distribution along the disc surface. Results of a conjugate heat transfer analysis of a spacer in the turbine section of a turboprop engine are then presented.

Journal Article↗
PubMed2001

Interposed colon between remnants of the small intestine exhibits small bowel features in a patient with short bowel syndrome.

We describe herein the case of a 48-year-old man who underwent emergency massive resection of the small intestine due to a strangulated ileus, which led to short bowel syndrome (SBS), as he was left with only 7 cm of jejunum and 8 cm of ileum with ileocecal valve. He then received interposition of a colon segment between the jejunum and ileum remnants isoperistaltically. For 24 months after the operation, he has been able to tolerate oral intake, but still requires partial home parenteral nutritional support during the night on a bimonthly basis. Biochemical and nutritional parameters, including the analysis of minerals and trace elements, indicated that the patient was in relatively good health. Histological examination revealed that the mucosa of the interposed colon showed hypertrophy and hyperplasia of the crypt glands, and cells resembling Paneth cells which are usually seen in the small intestine, suggesting that the colon segment exhibits adaptive changes to the small intestine. Colon interposition may be a useful technique in patients with SBS when the small bowel is too short for the other surgical considerations.

Anastomosis, Surgical↗
PubMed2001

Plasma, intestine and tumor levels of 5-fluorouracil in mice bearing L1210 ascites tumor following oral administration of 5-fluorouracil, UFT (mixed compound of tegafur and uracil), carmofur and 5'-deoxy-5-fluorouridine.

Several 5-fluorouracil (5-FU) derivatives, 1-hexylcarbamoyl-5-fluorouracil (HCFU), 5'-deoxy-5-fluorouridine (5'-DFUR) and UFT (mixed compound of tegafur and uracil), have been developed and clinically widely used. However, comparative pharmacokinetic studies of the parent compound and other fluorinated drivatives have not been precisely reported. The dosage of the oral clinical use for human cancer of 5-FU, HCFU, 5'-DFUR and UFT as tegafur (FT) is 200-300mg/d, 600mg/d, 800-1,200mg/d and 300-600mg/d respectively. These amounts of the drugs are almost equimolar. Previously, we reported the effect of oral equimolar administration of each four drugs on thymidilate synthase activity, deoxyribonucleotide metabolism and cell cycle progression in L1210 ascites tumor. (1,2) In this study, we examined the antitumor effect and 5-FU concentration in the plasma, intestine and tumor after oral equimolar administrations of each drug using BDF1 mice bearing L1210 ascites tumor. In our study, UFT showed the best life prolongation among these four drugs. The intestine 5-FU level was highest by treatment with 5-FU during the initial 4 h. The plasma 5-FU level was highest by treatment with HCFU for 4 h. But the tumor 5-FU level was highest by treatment with UFT over the 24 h. In spite of the high plasma 5-FU concentration after the treatment with HCFU, the 5-FU concentration in the tumor was below the detectable level until 24 h. These findings suggested that the highest specific accumulation of 5-FU in tumor cells may explain the best therapeutic results of UFT.

Administration, Oral↗
PubMed2000

Secologanin synthase which catalyzes the oxidative cleavage of loganin into secologanin is a cytochrome P450.

Secologanin synthase, an enzyme catalyzing the oxidative cleavage of the cyclopentane ring in loganin to form secologanin, was detected in microsomal preparations from cell suspension cultures of Lonicera japonica. The reaction required NADPH and molecular oxygen, and was blocked by carbon monoxide as well as by several other cytochrome P450 inhibitors, indicating that the reaction was mediated by cytochrome P450. Of the substrates examined, only specificity for loganin was demonstrated. A possible reaction mechanism is described.

Carbon Monoxide↗
PubMed1999

erbB-2 overexpression but no activation of beta-Catenin gene in extramammary Paget's disease.

Our previous study in extramammary Paget's disease showed neither p53 mutations nor allelic loss at selected loci implicated in other cancers, suggesting a pathogenesis of this skin cancer different from other common epithelial malignancies. To examine further the genetic defects in extramammary Paget's disease, we carried out molecular genetic analyses in 31 tumor samples obtained from 27 cases of extramammary Paget's disease without underlying malignancies. Immunohistochemistry using CB-11 monoclonal antibody revealed either membrane or cytoplasmic erbB-2 oncoprotein overexpression in none of the 13 primary in situ tumors, but in one recurrent in situ tumor, 10 of 13 invasive primary tumors and two of four lymph node metastases. Sensitive dual color fluorescence in situ hybridization analysis using probes for erbB-2 gene locus and chromosome 17 pericentromere, however, revealed different erbB-2 gene status in the erbB-2 overexpressing tumors. One recurrent in situ tumor and one lymph node metastasis showed definite gene amplification characterized by multiple scattered signals or a few large clustered erbB-2 signals, whereas four tumors with predominantly cytoplasmic erbB-2 overexpression were thought to have low-grade gene amplification. The remaining six tumors overexpressing erbB-2 showed no increase of erbB-2 copy numbers. No evidence of abnormal activation of the beta-catenin gene, a critical mediator of Wnt signaling pathway, in any tumor by immunohistochemical staining and by direct sequencing and reverse transcription-polymerase chain reaction analysis was found. Frequent overexpression of erbB-2 by either gene amplification or possible transcriptional activation in invasive primary tumors and metastases suggests an important part for this oncogene in the progression of extramammary Paget's disease.

Aged↗
PubMed1998

Amplification of c-erbB-2 in gastric cancer: detection in formalin-fixed, paraffin-embedded tissue by fluorescence in situ hybridization.

A total of 396 adenocarcinomas of the stomach were examined immunohistochemically using antibodies specific for the internal domain of human c-erbB-2 protein. Forty of these (consisting of 35 well-differentiated and 5 undifferentiated types) overexpressed c-erbB-2, as evidenced by cytoplasmic membrane staining; these tumors were further examined by fluorescence in situ hybridization using a cosmid probe for 17q11.2-12 (c-erbB-2 locus) on formalin-fixed, paraffin-embedded tissues. This technique enabled us not only to detect c-erbB-2 amplification on a cell-by-cell basis, but also to compare the gene amplification with the protein expression, observe topographical distribution, and establish quantitative pictures of the amplification in vivo condition. In all 40 tumors, we observed gene amplification and found that the cancer cell with the amplification corresponded to the cells overexpressing c-erbB-2. In eight mucosal carcinomas, signals were coalesced to one or two clusters, indicating that the amplified gene resided in a homogeneous staining region (HSR). Among 32 carcinomas invading beyond muscularis mucosae, approximately half were mostly composed of cells with the amplification; the others had populations of tumor cells with and without amplification, which were sometimes in separate zones or areas and sometimes mixed together. In 22 cancers, the amplified genes were exclusively in HSR; however, cancer cells with multiple scattered signals-suggesting that the amplified genes were translocated to other chromosomes-were found exclusively in 6 tumors and concurrently with HSR in 4 tumors. These findings suggest that: (a) the amplification produces c-erbB-2 in the HSR form generally early in the carcinogenesis of gastric adenocarcinomas; and (b) in the process of cancer development, the amplified gene is lost in some cancer cells by uneven segregation of HSR in mitosis, whereas in others, it is kept in HSR or translocated to other chromosomal positions, thereby preserving overexpression of c-erbB-2 protein.

Adenocarcinoma↗
PubMed1998

Amplification of c-myc, K-sam, and c-met in gastric cancers: detection by fluorescence in situ hybridization.

Gene amplifications of c-myc, K-sam, and c-met were examined in cancer nuclei isolated from 154 primary gastric adenocarcinomas by fluorescence in situ hybridization (FISH) using cosmid probes for 8q24 (c-myc locus) and 7q31 (c-met), as well as a DNA probe for K-sam synthesized by PCR. The results were compared with those of Southern blot analysis. Dual-color FISH using gene locus and chromosome-specific probes detected gene amplifications of c-myc in 24 tumors (15.5%), c-met in 6 tumors (3.9%), and K-sam in 3 tumors (2.9%). The six tumors with c-myc amplification had also been found to have amplified c-erbB-2 in our previous study, and coamplification of c-myc and c-met was found in two other tumors. This technique also differentiated the amplified genes on the homogeneous staining region (HSR) and on double minute chromosomes (DMs) in metaphase spreads and interphase nuclei of cell lines established from poorly differentiated adenocarcinomas, KATO III, SNU 16, and HSC 39. Examination of FISH images of these cell lines suggested that the high-level amplifications of c-myc found in primary tumors occurred mainly on DM in four tumors and on HSR in one, and those of K-sam occured on DM in two tumors and on HSR in one. No high-level amplification of c-met was found. These high-level amplifications were also detected in formalin-fixed, paraffin-embedded tissues from primary gastric tumors and metastatic lymph nodes, in some of which heterogeneity of gene amplification was demonstrated within the same tumor. We conclude that FISH is an important tool for examining the proto-oncogene aberrations in intact cells in solid tumors.

Blotting, Southern↗
PubMed1997

Amplification of the c-erbB-2 (HER-2/neu) gene in gastric cancer cells. Detection by fluorescence in situ hybridization.

Amplification of the c-erbB-2 gene was examined in 120 gastric adenocarcinomas by dual-color fluorescence in situ hybridization (FISH) using probes for centromere 17 and the 17q11.2-12. The results were compared with Southern blot analysis and immunohistochemistry of c-erbB-2 overexpression. FISH was successful in 105 tumors, and the amplification was found in 19 tumors. FISH on 17 tumors revealed high-level amplification; in 15, the predominant cancer populations had amplified c-erbB-2 gene with the signals forming one or two clusters, indicating that the amplified gene was present in homogeneously staining regions. In two tumors, most cancer cells had multiple scattered c-erbB-2 signals, indicating that the amplicon was within double-minute chromosomes. The other two tumors had a few additional copies of the c-erbB-2 gene. Seventeen tumors had increased numbers of the gene probably due to polysomy 17, and sixty-nine tumors had no aberrations of chromosome 17. Immunohistochemically, distinct membrane staining was found only in the 17 tumors with the high-level amplification. It is concluded that, in gastric adenocarcinomas, high-level amplification produces the c-erbB-2 gene principally in homogeneously staining region form and occasionally in double-minute form and is thought to control the over-expression of the protein in the cytoplasmic membrane.

Adenocarcinoma↗
PubMed1996

Numerical chromosome alterations in colorectal carcinomas detected by fluorescence in situ hybridization. Relationship to 17p and 18q allelic losses.

This study concerns DNA ploidy, numerical changes of chromosomes 7, 8, 10, 17 and 18, and allelic losses at chromosomes 17p13.3 (flanking the p53 gene) and 18q21 (location of the DCC gene) in 31 freshly resected colorectal tumours. Cytological smears were used to determine DNA ploidy by image analysis, and chromosome numbers by fluorescence in situ hybridization (FISH) using chromosome-specific pericentromeric alpha-satellite DNA probes. Allelic losses were assessed by Southern blotting and by the polymerase chain reaction loss of heterozygosity method. Approximately 50% of the tumours were aneuploid. There was heterogeneity with respect to chromosome numbers, but gains and losses of chromosomes, or both, were detected in all carcinomas examined, including 10 that were nonaneuploid by image analysis. Trisomy 7 was found in 74% of the tumours, and monosomy of chromosome 18 in 32%. Allelic loss at chromosome 17p13.3 was evident in 13 of 26 informative cases, and only one case exhibited monosomy 17. In comparison monosomy 18 was found in 10 cases; 7 of them corresponded to approximately half of the cases with allelic loss within the DCC gene, and the other three were noninformative. These findings indicate that the loss of one chromosome 18 is an important mechanism producing allelic deletion of the DCC gene in colorectal carcinomas. Our data also suggest that monosomy 18 is a useful indicator for studying colorectal cancer progression on a cell by cell basis.

Aneuploidy↗
PubMed1996

Effects of subtilisin cleavage of monomeric actin on its nucleotide binding.

The kinetics of ATP exchange on subtilisin-cleaved G-actin was investigated by measuring the fluorescence of 1,N6-ethenoadenosine 5'-triphosphate. The apparent dissociation rate of ATP (k-ATP) was 2.8-fold larger than that of intact G-actin in the presence of 300 microM free Ca2+. Analysis of the dependence of k-ATP on free Ca2+ showed that the dissociation rate constant of tightly bound Ca2+ was not significantly changed by subtilisin cleavage. On the other hand, an equilibrium binding study using 8-amino-2-[(2-amino-5-methylphenoxy)-methyl]-6-methoxyquinoline N,N,N',N'-tetraacetic acid (Quin 2) showed that the affinity of tightly bound Ca2+ for G-actin was reduced by about 13-fold after subtilisin treatment. Consequently, the stabilization by Ca2+ of ATP was weak in cleaved G-actin. Furthermore, the kinetic analysis of ATP exchange revealed that the binding equilibrium between ATP and divalent cation-free cleaved G-actin was much slower than that in the case of intact G-actin.

Actins↗
PubMed1996

Analysis of chromosome 17p13 (p53 locus) alterations in gastric carcinoma cells by dual-color fluorescence in situ hybridization.

Chromosome 17 and p53 gene locus alterations were determined on 67 gastric carcinomas by dual-color fluorescence in situ hybridization, using probes for centromere 17 and the 17p13.1 (p53 locus). The results were compared with loss of heterozygosity (LOH) at 17p13.3, direct sequencing of exons 5 to 9 of p53, and nuclear overexpression of p53 protein. Deletion of p53 was found in 26 of 67 tumors (39%). All 26 also showed LOH at 17p13.3, frequently overexpressed p53 protein, and had polysomy 17. The functional loss of p53 gene in these tumors, 85% of which were of intestinal type, appears to be caused by both deletion of 17p13.1 and missense mutation of the remaining allele. There were 9 tumors that had neither deletion nor LOH but had a large proportion of cancer cells that overexpressed p53 election. Despite evidence of LOH, there was no p53 deletion in 11 tumors. Finally, 21 tumors, mostly of diffuse type, showed neither deletions, LOH, nor p53 overexpression. Our data suggest that in gastric cancer, deletion of 17p is principally responsible for the allelic loss at the p53 gene and that analysis of deletions by the dual-color fluorescence in situ hybridization is a sensitive and useful approach to clarify chromosomal aberrations.

Carcinoma↗
PubMed1995

Preparation of specific antibodies against murine IL-1ra and the establishment of IL-1ra as an endogenous regulator of bacteria-induced fulminant hepatitis in mice.

Blocking monoclonal antibodies (mAbs) specific to mouse interleukin-1 receptor antagonist (IL-1ra) were prepared by immunizing Armenian hamsters with recombinant mouse IL-1ra. A sensitive and specific ELISA against mouse IL-1ra was also established. In Propionibacterium acnes-induced liver injury, P. acnes induced transient increase of serum tumor necrosis factor-alpha levels but not those of IL-1ra, IL-1, and IL-6. However, subsequent lipopolysaccharide (LPS) challenge induced the increase of serum levels of all these cytokines and the peak serum IL-1ra level was more than 20 times as high as serum IL-1 levels. Immunohistochemical analysis demonstrated that IL-1ra was predominantly produced by hepatocytes during the course of the priming phase by P. acnes and eliciting phase by LPS challenge. Furthermore, the administration of a mAb to mouse IL-1ra exacerbates the liver injury induced by P. acnes and sublethal dose of LPS, suggesting a protective role of endogenous IL-1ra in this liver injury model.

Animals↗