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Biomedical subjects

M Naito

Publications and source records attributed to M Naito.

At least 181 records · Page 10Linked to original sources
PubMed1998

Idiopathic renal arteriovenous fistula demonstrating a huge aneurysm with a high risk of rupture: report of a case.

This paper reports a case of an idiopathic renal arteriovenous fistula demonstrating a huge guitar-shaped aneurysm, which required a total nephrectomy. Although the patient insisted on having been asymptomatic, echocardiography and cardiac catheterization clearly revealed that the influence on hemodynamics was unexpectedly significant. Interestingly, the aneurysm was also considered to have a high risk of rupture, which was preoperatively suggested by an aneurysm wall projection discernible on both computerized tomograms and angiograms, and this suspicion was also convincingly supported by the perioperative and histopathological findings.

Aneurysm↗
PubMed1998

Myocardial CD36 expression and fatty acid accumulation in patients with type I and II CD36 deficiency.

Long-chain fatty acids (LCFA) are one of the major cardiac energy substrates, so understanding LCFA metabolism may help in elucidating the mechanisms of various heart diseases. CD36 is a multifunctional membrane glycoprotein that acts not only as a receptor for thrombospondin, collagen and oxidized low density lipoprotein but also as a receptor for LCFA. We investigated the relationship between CD36 expression in myocardial capillary endothelial cells and myocardial LCFA uptake in patients with CD36 deficiency. We analyzed CD36 expression in blood cells from 250 patients with heart diseases by means of a flow cytometer. In 218 patients, myocardial LCFA scintigraphy was performed with 123I-beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP). In 5 patients, myocardial capillary endothelial cells were examined immunohistochemically for CD36 expression. Eleven patients (4%) showed signs of type I CD36 deficiency (neither platelets nor monocytes expressed CD36). Twenty patients (8%) had type II CD36 deficiency (monocytes expressed CD36 but platelets did not). In all 11 patients with type I CD36 deficiency, no BMIPP accumulation was observed in the heart, but in 13 patients with type II CD36 deficiency, BMIPP accumulation in the heart was focally reduced, but there were no patients without BMIPP accumulation in the heart. Although the myocardial capillary endothelial cells from two CD36-positive patients expressed CD36, those from two patients with type I CD36 deficiency did not. In a patient with type II CD36 deficiency, some capillary endothelial cells displayed patchy CD36 expression. CD36 deficiency was documented in 31 (12%) patients with heart diseases. Because CD36 was not expressed in the myocardial capillary endothelial cells in patients with type I CD36 deficiency, type I CD36 deficiency is closely related to lack of myocardial LCFA accumulation and metabolism in the myocardium.

Adult↗
PubMed1998

Monoclonal antibodies to P-glycoprotein: preparation and applications to basic and clinical research.

P-Glycoprotein, a member of the ABC transporter group, plays an important role in anticancer drug resistance. Many monoclonal antibodies to P-glycoprotein have been developed and used to study the molecular and cellular functions of P-glycoprotein. These monoclonal antibodies were used for gene cloning, purification and reconstitution of P-glycoprotein, analysis of transport functions of P-glycoprotein, immunological detection and selective killing of tumors that express P-glycoprotein for diagnostic, and therapeutic purposes.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Gene therapy for hepatic micrometastasis of murine colon carcinoma.

BACKGROUNDS/AIMS: Pit cells are located in the hepatic sinusoids and are organ-associated natural killer cells that contribute to immune surveillance in the liver. In the present study, the interleukin-2 gene was introduced into hepatocytes using an adenovirus vector to induce interleukin-2 production in an attempt to enhance the natural killer activity of pit cells, leading to inhibition of metastasis of colon carcinoma. METHODS: The recombinant adenovirus vector "Adex1CAmIL2" was constructed by inserting an expression unit which was composed of the CAG promotor (cytomegalovirus enhancer plus chicken beta-actin promotor), murine interleukin-2 cDNA, and a rabbit beta-globin polyadenylation signal. After administration of Adex1CAmIL2 to mice (4x10(7) pfu per animal), the expression of murine interleukin-2 in hepatocytes was examined by immunostaining and in situ hybridization, and the natural killer activity of hepatic mononuclear cells was measured. Inhibition of hepatic metastasis of colon carcinoma was examined after infusion of colon 38 tumor cells into the superior mesenteric vein. RESULTS: After administration of Adex1CAmIL2, interleukin-2 mRNA expression was demonstrated in hepatocytes until day 7, and the serum interleukin-2 level was increased. The natural killer activity of hepatic mononuclear cells was markedly enhanced for 7-10 days. Hepatic metastasis was inhibited by administration of Adex1CAmIL2 until day 7 after tumor cell inoculation. CONCLUSION: These results suggest that gene therapy using Adex1CAmIL2 could be potentially useful for inhibiting hepatic micrometastasis by enhancing the natural killer activity of pit cells.

Actins↗
PubMed1998

Comparison of four monoclonal antibodies reacting with gastric gland mucous cell-derived mucins of rat and frog.

Features of four monoclonal antibodies (MAbs), PGM36, PGM37, PGM38 and HIK1083, reacting with the mucin derived from rat gastric gland mucous cells were compared. By applying enzyme linked immunosorbent assay, all of these MAbs reacted not only with the mucins purified from both rat and frog stomach, but also with the oligosaccharides obtained from the antigenic mucins by alkaline borohydride treatment. These MAbs could be characterized as distinct MAbs due to the immunohistochemical observation of rat cecal mucosa and the reactivity to paranitrophenyl derivatives of monosaccharides. These MAbs might be useful tools to compare the gastric gland-type mucins in different species of vertebrates and to investigate the heterogeneity of the carbohydrate structure of the mucin molecules of various origins.

Animals↗
PubMed1998

Enhanced metastasis of B16 melanoma cells by unexpected elevated expression of the metastasis-associated TI-241 (LRF-1-, Jun-Fos-related) gene treated with antisense oligonucleotide.

B16-F10 is a B16 mouse melanoma subline that preferentially metastasizes to the lung following intravenous injection. Previously we isolated TI-241 (LRF-1 homologue related to Jun-Fos) gene that was expressed higher in the high metastatic clone B16-F10 than the low metastatic clone F1. Transfection of TI-241 into F1 converted it into a high-metastatic cell. We studied the effect of antisense oligonucleotide designed to reduce the expression of TI-241 in B16-F10 cells, and observed an unexpected increase in the TI-241 level. The increase in the expression was maximal at 30 h, then it decreased during further culture with or without TI-241 antisense oligonucleotide. This increased TI-241 expression by antisense oligonucleotide was also observed in B16-F1 cells whereas sense oligonucleotide did not affect the expression. B16-F10 cells cultured with TI-241 antisense oligonucleotide showed enhanced experimental metastatic potential to the mouse lungs compared with untreated B16-F10 and B16-F10 cultured with TI-241 sense oligonucleotide.

Activating Transcription Factor 3↗
PubMed1998

Specific chromomeres on the chicken W lampbrush chromosome contain specific repetitive DNA sequence families.

Chromomeres 1 and 3 of the chicken W lampbrush chromosome contain most of the EcoRI and XhoI repeat sequence families respectively. These chromomeres were stained with DAPI and their sizes relative to other W chromomeres were observed. Their relative contents of EcoRI and XhoI repeats were determined using fluorescence in situ hybridization with genomic probes for each of the two repeat families. There were two types of W chromosome in the chickens (White Leghorn and Rhode Island Red) used in this study with respect to the amount of EcoRI repeat. A high-copy-number type has about 4000 copies of the 1.2-kb repeat per genome and shows a large fluorescence signal on W chromomere 1. A low-copy-number type has about 700 copies per genome and does not have a detectable chromomere 1 on W chromosome, nor does it show FISH labelling in the region normally occupied by chromomere 1. The genome of Fayoumi chickens has about one-sixth the amount of the XhoI sequence family of White Leghorns. W lampbrush chromomere 3 is much smaller and its FISH labelling with the XhoI probe is much weaker in Fayoumis than in White Leghorns. These results demonstrate that in the chicken W chromosome, specific chomomeres are occupied by specific DNA repeat sequence families.

Animals↗
PubMed1998

Establishment of a mutant from human monocytic leukaemia U937 that exhibits a genetically dominant resistance to TNF alpha-induced apoptosis.

Tumour necrosis factor-alpha (TNF alpha) is a cytokine that induces apoptosis in various cell systems by binding to a TNF receptor (TNFR). To study TNF alpha-induced apoptosis, we isolated and characterized a novel TNF alpha resistant variant, U937/TNF clone II-5, from human monocytic leukaemia U937 cells. The II-5 cells resist apoptosis by TNF alpha and anti-Fas antibody but not by anticancer drugs, such as VP-16 and Ara-C. Somatic cell hybridization between U937 and II-5 showed that the apoptosis resistance to TNF alpha in II-5 was genetically dominant. This dominant mutation in II-5 cells blocks TNF alpha-induced disruption of mitochondrial membrane potential and caspase-3 activation. Expression of TNFR, Fas and Bcl-2 family proteins were not changed in II-5 cells. These results suggest that the apoptosis-resistant II-5 cells could have a functional defect in apoptosis signalling from TNFR to mitochondria and caspase activation. The II-5 cells could be useful in studying the signalling linkage between TNFR and mitochondria.

Journal Article↗
PubMed1998

Older (but not younger) siblings facilitate false belief understanding.

Results from 4 experiments and an analysis in which all data from 444 English and Japanese children are pooled show (a) a linear increase in understanding false belief with the number of older siblings, (b) no such effect for children younger than 3 years 2 months, (c) no helpful effect of younger siblings at any age (despite the large sample), (d) no effect of siblings' gender, and (e) no helpful effect of siblings on a task measuring children's understanding of how they know something. Discussion involves speculation about how older siblings may assist children (e.g., through pretend play and mental state language) and how different aspects of a theory of mind may develop through different means.

Age Factors↗
PubMed1998

Selective induction of apoptosis in Philadelphia chromosome-positive chronic myelogenous leukemia cells by an inhibitor of BCR - ABL tyrosine kinase, CGP 57148.

The BCR - ABL tyrosine kinase has been implicated as the cause of Philadelphia chromosome (Ph1)-positive leukemias. We report herein that CGP 57148, a selective inhibitor of the ABL tyrosine kinase, caused apoptosis specifically in bcr - abl-positive chronic myelogenous leukemia (CML) cells, K562 and KYO-1. Upon treatment with CGP 57148, CRKL, a specific substrate for BCR - ABL that propagates signals via phosphatidylinositol-3' kinase (PI3K), was dephosphorylated, indicating inhibition of BCR - ABL tyrosine kinase at the cellular level. Likewise, MAPK/ERK, a downstream mediator of Ras, was also dephosphorylated. Caspase activation and cleavage of retinoblastoma protein (pRB) accompanied the development of CGP 57148-induced apoptosis. Inhibition of caspase suppressed apoptosis and the cleavage of pRB, and in turn arrested cells in the G1 phase. These results indicate that CGP 57148 shows apoptogenic and anti-proliferative effects on bcr - abl-positive cells by blocking BCR - ABL-initiated signaling pathways.

Apoptosis↗
PubMed1998

Peritoneal macrophages play an important role in eliminating human cells from severe combined immunodeficient mice transplanted with human peripheral blood lymphocytes.

To elucidate the mechanism of human cell elimination from severe combined immunodeficient (SCID) mice transplanted with human peripheral blood lymphocytes (hu-PBL-SCID mice), we explored the immunocytes in the peritoneal cavity in SCID mice where human PBL were transferred. When the phenotype of peritoneal exudate cells (PEC) was compared by flow cytometry among three congenic strains of SCID mice that differ in their acceptability for human PBL, the PEC in NOD-scid mice, which exhibit the highest acceptability, contained the smallest number of F4/80lo/-Mac-1(+)-activated macrophages. Moreover, the proportions of natural killer cells in PEC of the three strains of SCID mice were not always correlated with the acceptability. These findings suggest the possibility that peritoneal macrophages eliminate human cells in hu-PBL-SCID mice. To verify this hypothesis, we evaluated the engraftment of human PBL into SCID mice that were treated with liposome-encapsulated dichloromethylene diphosphonate, which selectively depletes macrophages by inducing apoptosis, or 8-aminoguanidine hemisulphate salt, an inhibitor of inducible nitric oxide synthase of macrophages. As a result, both of these regimens improved engraftment of human PBL, indicating that peritoneal macrophages take part in human cell elimination in the peritoneal cavity of hu-PBL-SCID mice and that it is mediated, at least in part, by direct macrophage cytotoxicity utilizing nitric oxide.

Animals↗
PubMed1998

Immunological characterization of alpha antigen of Mycobacterium kansasii: B-cell epitope mapping.

Mapping of B-cell epitopes on alpha antigen of Mycobacterium kansasii (K-alpha) was carried out by using recombinant truncated K-alpha fusion peptides. We observed that two immunodominant B-cell epitopes (amino acids 222-268 and 267-306) and one minor epitope (amino acid 249-286) were located in the C-terminal region of K-alpha. The other three minor B-cell epitopes were mapped in N-terminal (amino acids 80-98 and 99-166) and central (amino acid 174-204) regions of K-alpha. All defined epitopes were common to Mycobacterium tuberculosis and M. kansasii. Besides these common epitopes, a region in K-alpha (amino acid 290-319) revealed different reactivities between antibodies against K-alpha and alpha antigen of M. tuberculosis. These findings may provide a basis for development of serodiagnosis that can distinguish between M. kansasii and M. tuberculosis infections.

Animals↗
PubMed1998

Donor primordial germ cell-derived offspring from recipient germline chimaeric chickens: absence of long-term immune rejection and effects on sex ratios.

1. Germline chimaeric chickens were produced by the transfer of primordial germ cells, and the generation of donor-derived offspring was examined for a maximum of 146 weeks. 2. The frequencies of donor-derived offspring from the chimaeras were 47% to 97%, and no apparent changes in frequency were observed with increasing age during the test period. 3. Differentiation of donor primordial germ cells into functional gametes appeared to be restricted to a degree at some developmental stage in the gonads of chimaeric chickens of the opposite sex.

Animals↗
PubMed1998

MR and CT cholangiography in evaluation of the biliary tract.

OBJECTIVE: To compare MR and CT cholangiography (MRC and CTC) in evaluating the anatomy of the extrahepatic biliary tract and the pathology related to the gallbladder. MATERIAL AND METHODS: Twenty-three patients underwent MRC and CTC with a biliary contrast medium for investigation of biliary disease. 3D displays of both were also obtained. Endoscopic retrograde cholangiography was performed in 17 patients, and the pathology of all 23 was evaluated. RESULTS: Overall, the image quality was higher with CTC than with MRC (4.7 vs 3.9, p < 0.05). The cystic duct was demonstrated better by CTC than MRC (p < 0.05). Multiplanar reformation (MPR) and source images provided additional information to that obtained from 3D MRC and CTC images. Gallstones were revealed in 6 patients by CTC and in 5 of these 6 by MRC. In 2 patients with cholecystitis, CTC demonstrated gallbladder wall thickening but MRC did not. In 3 patients with adenomyomatosis. MRC demonstrated Rokitansky-Aschoff sinuses (RAS) while CTC demonstrated focal gallbladder wall thickening in all 3 and RAS in 1 of them. CONCLUSION: Both MRC and CTC provided anatomical and pathological information about the biliary system. With both techniques, however, either MPR or source images proved necessary in addition for evaluating the biliary system anatomy and pathology. The gallbladder wall was depicted clearly in source CTC, but MRC is recommended for the evaluation of adenomyomatosis because it depicts RAS clearly.

Adult↗
PubMed1998

Sesamolin inhibits lipid peroxidation in rat liver and kidney.

Although the sesame lignans, sesaminol and sesamolinol, have been shown to possess antioxidative activity, less is known about the metabolism and antioxidative properties of sesamolin, a major constituent of sesame oil. To determine the ability of sesamolin to act as an antioxidant in vivo, we fed rats a diet containing 1% sesamolin for 2 wk and studied its metabolism and its effects on oxidative stress. About 75% of the ingested sesamolin was excreted unmetabolized in feces, but it was not detected in urine. Sesamolin and its metabolites, sesamol and sesamolinol, were excreted primarily as sulfates and glucuronides. The amount of sesamolin and its metabolites was lower in the plasma than in the liver or kidneys. When we compared rats fed a diet containing 1% sesamolin for 14 d with those fed a control diet, we found that liver weight was significantly greater in the former group. Lipid peroxidation activity, measured as 2-thiobarbituric acid reactive substances, was significantly lower in the kidneys and liver of the sesamolin-fed rats than in the controls. In addition, the amount of 8-hydroxy-2'-deoxyguanosine excreted in the urine was significantly lower in the sesamolin-fed rats. These results suggest that sesamolin and its metabolites may contribute to the antioxidative properties of sesame seeds and oil and support our hypothesis that sesame lignans reduce susceptibility to oxidative stress.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1998

Therapeutic approach to drug resistant tumors.

Drug resistance is a major problem in cancer chemotherapy. P-glycoprotein plays a major role in multidrug resistance in cancer cells. P-glycoprotein is expressed in some normal tissues and has physiological functions. These include protecting the brain against toxic substances at the blood-brain barrier site, excreting toxic substances from the liver, kidney, and gastrointestinal tracts, and transporting steroidal hormones in the adrenal grand. Once expressed in cancer cells. P-glycoprotein effluxes a variety of anticancer drugs, such as doxorubicin, vinca alkaloids, etoposide and taxol, and thereby allows cancer cells to show resistance to these drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Immunological quantitation of DT-diaphorase in carcinoma cell lines and clinical colon cancers: advanced tumors express greater levels of DT-diaphorase.

NAD(P)H:quinone oxidoreductase (DT-diaphorase; DTD) plays a major role in activating mitomycin C (MMC) in human colon and gastric carcinoma cell lines. Thus, measurement of DTD in clinical tumor samples could be beneficial in designing adjuvant chemotherapy. We explored immunological quantitation of DTD protein using a monoclonal antibody against DTD, demonstrating a close correlation between protein expression and enzyme activity of DTD in colon and gastric carcinoma cell lines and in colorectal tumor samples. This indicates that such immunoblot analysis is a simple alternative method for quantitating DTD in clinically excised samples. In most colorectal tumor samples, the tumors expressed larger amounts of DTD than did the peripheral normal tissues, suggesting a selective toxicity of MMC toward tumor cells. Also tumors with nodal metastases showed significantly higher DTD levels than did tumors without metastasis. These results raise the possibility that DTD expression is related to tumorigenesis and malignant progression of colorectal tumors. Measurement of DTD by the immunological method described here could be beneficial in designing a rational adjuvant chemotherapy with MMC.

Adenocarcinoma↗