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Biomedical subjects

S Okamura

Publications and source records attributed to S Okamura.

At least 73 records · Page 4Linked to original sources
PubMed1999

Labeled carcinoembryonic antigen antibodies excitable by infrared rays: a novel diagnostic method for micro cancers in the digestive tract.

OBJECT: An indocyanine green derivative (ICG-sulfo-OSu) was used as the labeling substance for monoclonal antibody, and a fluorescence imaging system appropriate for ICG-sulfo-OSu excitable by infrared rays (IR) was developed. The goal of this study was to demonstrate antibody labeling at the tissue level using this new imaging system. MATERIALS AND METHODS: ICG-sulfo-OSu labeled mouse anti-human carcinoembryonic antigen (CEA) monoclonal antibody, a newly developed imaging system, and an infrared ray microscope were employed in this experiment. Paraffin sections of human colon cancer previously proven to have cross-reactivity to anti-CEA antibody were examined. RESULTS: Positive staining was seen as a brownish discoloration of oxidized 3,3'-diaminobenzidine tetrahydrochloride (DAB) in sections that reacted with ICG-sulfo-OSu-labeled anti-CEA antibody, and the fluorescence was well-matched with the oxidized DAB-positive sites. CONCLUSION: Specific antibodies labeled with ICG-sulfo-OSu have significant affinity to cancer cells and seem to reflect sufficient amounts of fluorescence by IR to be useful in a system for the endoscopic detection of micro cancers using the immunohistochemical staining method.

Adenocarcinoma↗
PubMed1999

The utility and limitations of an ultrasonic miniprobe in the staging of gastric cancer.

To determine the utility and limitations of an ultrasonic miniprobe (UMP) in the staging of gastric cancer, we evaluated 46 patients who underwent endoscopic ultrasonography (EUS) using an UMP and who were histologically determined to have gastric cancers. In every case, UMP findings were compared with histopathological findings after treatment. The total accuracy of UMP relative to the depth of tumor invasion was 71.7% (33/46 cases). Accuracy with respect to T1-m tumor diagnosis was 75.7% (22/29 cases), and for T1-sm, 76.9% (10/13 cases), but accuracy for T2 tumor diagnosis was low, due to ultrasound attenuation. When the analysis was carried out based on the size of tumor, the accuracy for UMP was 50.0% (9/18 cases) for all tumors over 20 mm and 85.7% (24/28 cases) for all tumors smaller than 20 mm. We conclude that UMP is suitable for investigation of tumor extension when the lesion is superficial and/or small gastric cancers which do not cause ultrasonic attenuation, but not when the tumor is large or located in certain sites, although conventional EUS is useful in some of these cases.

Aged↗
PubMed1999

Isolation and characterization of a novel TP53-inducible gene, TP53TG3.

We applied the differential mRNA display method to isolate genes regulated by wild-type TP53 in cells of a colon-cancer line (SW480) in which we had established an inducible TP53 expression system under the control of the lactose operon. Here we report isolation and characterization of a novel TP53-inducible gene, termed TP53TG3 (TP53 target gene 3). Its DNA sequence was identical to sequences present in two BAC clones that had been mapped to chromosome band 16p13. The gene expressed several transcripts by alternative splicing; the two major transcripts, TP53TG3a and TP53TG3b, encoded 124- and 132-amino-acid peptides that were expressed predominantly in testis. Immunohistochemical analysis using cancer cells (HeLa or H1299) that had been transfected with plasmid DNA designed to express the MYC-fused TP53TG3 proteins indicated that these products were present mainly in the cytoplasm 20 hr after transfection. However, 40 hr after transfection, the recombinant proteins had accumulated in the nuclei of some cells. Because no known nuclear localization domain was present in the amino acid sequence, we suspect that this protein plays an important role in the TP53-mediated signaling pathway, when it forms complexes with other protein(s) and is transferred by them into the nucleus. Genes Chromosomes Cancer 26:329-335, 1999.

Amino Acid Sequence↗
PubMed1999

Identification of seven genes regulated by wild-type p53 in a colon cancer cell line carrying a well-controlled wild-type p53 expression system.

We applied a differential display method to screen mRNAs isolated from a newly established cell line that carried a wild-type p53 transgene under control of the lactose operon. To investigate the p53 signaling pathway, we looked for genes whose expression was significantly induced or suppressed by induction of wild-type p53 protein, and identified seven. DNA sequence analyses revealed that the two genes that were upregulated encoded isozyme 6 of aldehyde dehydrogenase (ALDH6) and subunit I of cytochrome c oxidase (COI). The five genes that were downregulated encoded protein-tyrosine kinase (Syk), high mobility group chromosomal protein 17 (HMG-17), transferrin receptor, human alpha-tubulin, and sds22-like protein. The results indicated that genes related to cell cycle regulation, cell respiration, and cytoskeletal structure are involved in the process of growth arrest induced by wild-type p53.

Cell Cycle↗
PubMed1998

Aggressive non-Hodgkin's lymphoma after successful eradication of Helicobacter pylori and regression of gastric lymphoma of mucosa-associated lymphoid tissue.

A 57-year-old woman presented to our clinic with low-grade gastric lymphoma of mucosa-associated lymphoid tissue (stage IE) and Helicobacter pylori infection. She received a 2-week course of omeprazole and clarithromycin, resulting in eradication of H. pylori and histological disappearance of the lymphoma. However, 9 months later (May 1996), multiple mass lesions were found around the pancreas and hepato-duodenal ligament on abdominal computed tomography. Inguinal lymph node biopsy revealed aggressive nodal type B-cell non-Hodgkin's lymphoma, diffuse large cell type. She received chemotherapy with cyclophosphamide, adriamycin, vincristine, and prednisolone, but failed to achieve remission and died in December 1996. There was no evidence of recurrent gastric lymphoma. This case emphasizes the importance of performing follow-up examinations to detect other neoplasms in patients with gastric lymphoma of mucosa-associated lymphoid tissue.

Diagnosis, Differential↗
PubMed1998

Novel germline mutations of hMSH2 in a patient with hereditary nonpolyposis colorectal cancer (HNPCC) and in a patient with six primary cancers.

We screened for germline mutations of mismatch repair genes, hMLH1 and hMSH2, in five Japanese families carrying hereditary nonpolyposis colorectal cancer (HNPCC) and in a patient with multiple primary cancers. Screening the entire coding regions of both genes using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis, we found two novel germline mutations in hMSH2. One was a 1-bp insertion in exon 12, detected in a patient who had undergone surgery six times for independent tumors (four primary colorectal carcinomas, a small intestinal carcinoma, and an endometrial cancer). The other, in a second patient, was a missense mutation from CTT to TTT at codon 390 in exon 7 that resulted in substitution of phenylalanine for leucine. This conservative alteration was not found in any of 50 normal controls, but we cannot exclude the possibility that it may represent a rare polymorphism rather than a factor in the disease.

Adult↗
PubMed1998

The activation of eNOS by copper ion (Cu2+) in human pulmonary arterial endothelial cells (HPAEC).

We have previously reported that Cu2+ endothelium-dependently dilated rat pulmonary arterial rings in a few minutes by increasing NO production via constitutive endothelial nitric oxide synthase (eNOS) activation in rat pulmonary arterial endothelial cells (Eur. J. Pharmacol., 1997). In the present study, using cultured human pulmonary arterial endothelial cells (HPAEC), we assessed the effects of divalent cations (Cu2+, Mn2+, Zn2+, and Fe2+) on NOS activity in crude cell extracts and intact cells. NO synthase activity was measured by monitoring the conversion of L-[14C] arginine to L-[14C] citrulline. The NOS enzyme in crude HPAEC extract showed similar characteristics to previously reported eNOS from other sources. All the divalent cations tested suppressed the NOS activity in crude cell extract by about 50% at 1 x 10(-4) M, but only Cu2+ from 10(-6) M increased eNOS activation dose dependently with a significant elevation in whole-cell assay. Extracellular Ca2+ was prerequisite to the eNOS activation by Cu2+ in intact cells. Furthermore, we measured NO production determined as NOx (NO, .NO2-, and .NO3-) from HPAEC using NO chemiluminescence analyzer. HPAEC monolayers were treated with either buffer alone, Cu2+ (10(-4) M) or thapsigargin (10(-6) M). The amount of .NOx increased from 10.93 (pmoml/ml/10(6) cells) to 41.27 (pmol/ml/10(6) cells) by thapsigargin (10(-6) M) and to 45.24 (pmol/ml/10(6) cells) by Cu2+ (10(-4) M). The increase in NOx by Cu2+ was inhibited by L-NMMA. These results indicated that Cu2+, but not Mn2+, Zn2+, and Fe2+, causes the activation of eNOS, while Cu2+, Mn2+, Zn2+, and Fe2+ directly suppressed eNOS activity extracted from HPAEC. Further, our study showed that extracellular Ca2+ was essential for eNOS activation by Cu2+.

Arginine↗
PubMed1998

Development of agents for reinforcement of fluorescence on near-infrared ray excitation for immunohistological staining.

Fluorescence intensity of indocyanine green (ICG) derivative (ICG-sulfo-OSu) was too low for its use to detect microlesions. Therefore, we examined the effects of reinforcement agents on ICG-sulfo-OSu labeled antibodies. Solutions of distearoylphosphatic acid sodium salt (DSPA) and octylglucoside (OG) in physiological phosphate buffered saline (PBS) were found to increase the intensity of fluorescence of ICG-sulfo-OSu labeled antibodies, with shift in the fluorescence peak wavelength from 804 to 821 nm.

Antibodies↗
PubMed1998

The activation of nitric oxide synthase by copper ion is mediated by intracellular Ca2+ mobilization in human pulmonary arterial endothelial cells.

The aim of the study was to elucidate the vasodilatory mechanism due to Cu2+ by assessing nitric oxide (NO) production as determined by NOx (NO, NO2-, and NO3-) that is released from human pulmonary arterial endothelial cell (HPAEC) monolayers using a NO chemiluminescence analyzer, and also to assess Ca2+ movement using 45Ca and fura 2 in HPAEC. Cu2+ (10(-6)-10(-4) M) significantly increased NO production in a dose-dependent manner when extracellular Ca2+ was present. 45Ca influx into the adherent cells was dose-dependently enhanced by Cu(2+) (10(-6)-10(-4) M), but not by Mn(2+), Zn(2+) or Fe(2+). [Ca2+]i, measured by monitoring the fluorescence changes of fura 2, was significantly elevated in the presence of Cu2+. The increase in [Ca2+]i induced by Cu2+ was inhibited by either diethyldithiocarbamate (DDC) or the depletion of extracellular Ca2+. The dihydropyridine receptor agonist, BayK8644, significantly attenuated the Cu2+-induced increase in [Ca2+]i in a dose dependent manner and nitrendipine or nifedipine, the dihydropyridine receptor antagonists, dose-dependently inhibited a Cu2+-induced increase in [Ca2+]i. These results suggest that Cu2+ activates eNOS through the mechanism of [Ca2+]i elevation due to Ca2+ influx into HPAEC and that the Cu2+-induced [Ca2+]i elevation in HPAEC is likely due to activation of the dihydropyridine-like receptors.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

Effect of thrombopoietin on proliferation of blasts from CD7-positive acute myelogenous leukaemia.

We investigated the effect of thrombopoietin (TPO) on the growth of leukaemic blasts from 30 acute myelogenous leukaemia (AML) patients according to the surface expression of CD7 and CD34: 10 patients were CD7 positive (CD7+), nine were CD7 negative/CD34+ (CD7-/CD34+) and the remaining 11 were CD7-/CD34-. Significant growth response of leukaemic blasts to TPO was observed in 10/10 CD7+, 5/9 CD7-/CD34+ and 2/11 CD7-/CD34- AML cases using 3H-thymidine incorporation. Synergistic stimulatory effects of TPO with stem cell factor (SCF), interleukin-3 (IL-3), granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor were observed in both TPO-responding cases (9/17) and TPO-non-responding cases (8/13). In a leukaemic blast colony assay. significant growth response to TPO was observed in 5/6 CD7+ and 4/17 CD7-AML cases examined. However, the effect of TPO on the growth of CD7+ leukaemic blasts was not so potent as that of IL-3 and SCF, both of which support the proliferation of primitive haemopoietic progenitors. Expression of c-mpl (TPO receptor) was significantly higher in CD7+ AML cases than in CD7- cases, suggesting a relationship between expression of c-mpl and proliferative response to TPO. These data indicate that CD7+ leukaemic blasts express functional TPO receptors and proliferate in response to TPO. These observations also imply that CD7 expression on AML blasts may indicate involvement of leukaemic progenitors at an early stage of multipotent haemopoietic stem cells.

Adolescent↗
PubMed1998

Action of interleukin-3 on the proliferation of leukaemic progenitor cells from patients with acute myeloblastic leukaemia.

In the present study, we examined the effects of interleukin-3 (IL-3) on the proliferation of leukaemic progenitor cells from 11 Japanese patients with acute myeloblastic leukaemia (AML), including the effect of its combination with granulocyte/macrophage colony-stimulating factor (GM-CSF) or granulocyte colony-stimulating factor (G-CSF). The results showed that IL-3 sufficiently stimulated the proliferation of AML progenitor cells in almost all the cases examined, and that the stimulation pattern of IL-3 was similar to that of GM-CSF, although different from that of G-CSF. Furthermore, IL-3 worked synergistically with G-CSF, whereas IL-3 and GM-CSF together were less actively synergistic (P < 0.05). These findings suggest the possibility of IL-3/G-CSF/cytosine arabinoside (Ara-C) combination therapy, which may be able to enhance the cytotoxic effect of Ara-C on AML progenitor cells powerfully in a wider range of patients including cases refractory for IL-3/Ara-C combination therapy.

Adolescent↗
PubMed1998

Usefulness of surface phenotype study of intrathyroidal lymphocytes obtained by fine needle aspiration cytology in autoimmune thyroid disease and malignant lymphoma of the thyroid.

OBJECTIVES: The surface phenotypes of intrathyroidal lymphocytes have been studied in various thyroid diseases. In most of the previous reports, intrathyroidal lymphocytes were obtained by surgical operation. We evaluated the usefulness of surface phenotype study of intrathyroidal lymphocytes obtained by fine needle aspiration in the diagnosis of Graves' disease, chronic thyroiditis, and malignant lymphoma of the thyroid. PATIENTS AND DESIGN: Eighty-seven untreated patients including 24 with Graves' disease, 59 with chronic thyroiditis, and 4 with malignant lymphoma of the thyroid, and 2 treated patients with malignant lymphoma of the thyroid were studied. Surface phenotypes of the peripheral lymphocytes and the intrathyroidal lymphocytes obtained by fine needle aspiration were analyzed using a FACScan and the monoclonal antibodies: anti-Leu5b/CD2, Leu4/CD3, Leu3a/CD4, Leu2a/CD8, and Leu12/CD19. Percentages of cells positive for each monoclonal antibody were calculated. In one case with malignant lymphoma, monoclonal antibodies to surface-immunoglobulin markers were also studied. RESULTS: In peripheral lymphocytes, the percentage of positive cells in each phenotype was almost normal in each disease. In intrathyroidal lymphocytes, the percentage of CD19 positive cells was increased, and the percentage of CD2 and CD3 positive cells was reduced compared to those of peripheral lymphocytes in each disease. The percentage of intrathyroidal CD19 positive cells was remarkably high in malignant lymphoma, constituting more than 70% of cells. In Graves' disease, a relative decrease in the percentage of intrathyroidal CD4 positive cells and an increase in CD8 positive cells compared to peripheral lymphocytes were observed. In 2 treated patients with malignant lymphoma of the thyroid, the intrathyroidal CD19 positive cells almost disappeared in a patient shortly after successful treatment, and reappeared to constitute 76% of cells in a patient in relapse. In one case with malignant lymphoma in which monoclonal antibodies to surface-immunoglobulin markers were studied, the clonality of the affected cells could be demonstrated; more than 70% of the cells were positive for kappa light-chain and mu and delta heavy-chain. This finding was proved by subsequent immunohistochemical study based on open biopsy. CONCLUSIONS: Surface phenotype study of intrathyroid lymphocytes obtained by fine needle aspiration has limited utility in the evaluation or diagnosis of Graves' disease and chronic thyroiditis. However, this simple rapid method is very helpful in the diagnosis and follow up of malignant lymphoma of the thyroid.

Adult↗
PubMed1998

Identification of a carbohydrate-binding site in Physarum haemagglutinin I.

Carbohydrate-binding peptides from trypsin-digests of Physarum lectins (haemagglutinins I and II) were isolated by affinity column chromatography. The amino acid sequence of the peptide fragment from haemagglutinin I was determined to be 48TVHQSWY54. A similar amino acid sequence was found in the peptide fragment from haemagglutinin II, in which alignment of valine, histidine, tryptophan and tyrosine was identical. Deletion of the heptapeptide sequence (TVHQSWY) by site-directed mutation abolished the haemagglutinating activity. The replacement of Trp53 by alanine resulted in a complete loss of the haemagglutinating activity, suggesting that the tryptophan residue in the heptapeptide sequence is essential for carbohydrate binding.

Amino Acid Sequence↗
PubMed1998

Identification of lipid inhibitor of mammalian phospholipase D.

Phospholipase D (PLD) is implicated in important cellular processes, such as hormone action, inflammation, secretion, mitogenesis, and neural activity. Recent studies using cell-free systems have shown that the enzyme activity is modulated by both positive and negative regulators. During an attempt to purify PLD from pig colon mucosa, we noted the presence of a PLD inhibitor in the tissue extract. The inhibitor was purified and identified as comprising lysophosphatidylserine, phosphatidylinositol, and lysophosphatidylinositol, of which lysophosphatidylserine was the most potent. These lipids affected all of the PLD isoforms examined, oleate-dependent PLD, ARF-dependent PLD (PLD1a, PLD1b), and phosphatidylinositol 4,5-bisphosphate-dependent PLD (PLD2), in the concentration range of the 1 or 10 microM order. In contrast to lysophosphatidylserine, the diacyl counterpart phosphatidylserine was without effect in the same concentration range. PLD inhibition by lysophosphatidylserine could not be reversed by an increase in the concentration of the substrate phosphatidylcholine or activator phosphatidylinositol 4,5-bisphosphate.

Animals↗
PubMed1998

Analysis of the granulocyte colony-stimulating factor receptor gene structure using PCR-SSCP in myeloid leukemia and myelodysplastic syndrome.

The membrane-proximal cytoplasmic region of the granulocyte colony-stimulating factor receptor (G-CSFR) is known to be essential for the proliferation signal, with a more distal region being required for the differentiation signal. Such a separation of functional domains raises the possibility that mutations occurring at these regions may contribute to cell proliferation in the absence of differentiation, this being the most important characteristic in acute leukemia cells. Therefore, we analysed the structural abnormalities at the transmembrane and cytoplasmic region of G-CSFR in a significant number of patients with various myeloid malignancies. When we examined the genomic DNA of G-CSFR obtained from 41 patients with acute myelogenous leukemia (AML), 18 with chronic myelogenous leukemia (CML), 7 with myelodysplastic syndrome (MDS), 2 with chronic myelomonocytic leukemia and 1 with chronic neutrophilic leukemia, we found a polymorphism in 3 patients, but no significant pathogenic mutations in any patients. The screening for this polymorphism in 100 hematologically normal controls revealed that it may be useful as a linkage marker for population and family studies, because the heterozygosity index is at a high level (0.055). While there have been several reports discussing the leukemogenic potential of mutations in the cytokine/hematopoietin receptor superfamily, genetic alterations in the transmembrane and cytoplasmic region of G-CSFR do not seem to play a pathogenic role in leukemia.

Humans↗