Biomedical subjects

T Abe

Publications and source records attributed to T Abe.

At least 343 records · Page 19Linked to original sources

PubMed2000

An improved rapid procedure for fluorescence in situ hybridization that is applicable to intraoperative cancer cytodiagnosis.

Fluorescence in situ hybridization (FISH) is among the most simple and useful methods for detecting numerical and structural aberration of chromosomes but it requires 12-24 h to complete. We devised a rapid FISH method that can be performed within 2 h. Here we describe the technique, which we have found to be extreme simple and as sensitive and specific as standard FISH, making it highly suitable for clinical use.

Adult↗

PubMed2000

Does prolactin releasing peptide receptor regulate prolactin-secretion in human pituitary adenomas?

Prolactin-releasing peptide (PrRP) and its receptor (PrRP-R) have recently been characterized and cloned. PrRP functions as a prolactin-secreting factor through binding with PrRP-R, which is extensively expressed in the human pituitary. We studied the expression of PrRP-R in human pituitary adenomas. Pituitary adenomas were collected from 13 patients by transsphenoidal resection. Six patients had prolactin-secreting adenomas, three had adrenocorticotropic hormone-secreting adenomas, one had a growth hormone -secreting adenoma, and three had non-secreting adenomas. All pituitary adenomas examined by reverse transcription-polymerase chain reaction analysis expressed PrRP-R. When semiquantitative competitive PCR was performed to determine the relative amounts of the PrRP-R mRNA expression level, there was no correlation between plasma prolactin levels and PrRP-R expression levels. These results suggest that the plasma prolactin level is regulated by means other than signal transduction through PrRP-R activation.

Adrenocorticotropic Hormone↗

PubMed2000

Novel arbekacin- and amikacin-modifying enzyme of methicillin-resistant Staphylococcus aureus.

An aminoglycoside-modifying enzyme in arbekacin-resistant methicillin-resistant Staphylococcus aureus (MRSA), exhibiting 4'''-N-acetylation, was examined. Although the MRSA strain with AAC(4''') had no AAC(6')-APH(2") activity, a DNA fragment of the AAC(6')-APH(2") gene was amplified by PCR and the purified N-terminal 30-amino acid sequence of this AAC(4''') was identical to AAC(6')-APH(2"). Direct DNA sequencing of this 'silent' AAC(6')-APH(2") gene revealed a single point mutation leading to a substitution of Gly for Asp80, through which the secondary structure is affected. A change in protein conformation could lead to a cleavage and a change of the enzymatic activity. We propose a new aminoglycoside-resistance mediated by AAC(4''') is caused by a mutation-modified AAC(6')-APH(2").

Acetyltransferases↗

PubMed2000

Molecular identification of a rat novel organic anion transporter moat1, which transports prostaglandin D(2), leukotriene C(4), and taurocholate.

We have isolated a rat novel multispecific organic anion transporter, moat1. The isolated clones were originated by alternative splicing of the moat1 mRNA. The nucleotide sequences predict a protein of 682 amino acids with moderate sequence similarity to LST-1, the oatp family, and the prostaglandin transporter. Northern blot analysis of rat moat1 identified a predominant transcript of 4.4 kilonucleotides in all tissues. Northern blot and in situ hybridization analyses of rat brain further indicated that moat1 mRNA is widely distributed in neuronal cells of the central nervous system, especially in the hippocampus and cerebellum. moat1 transports prostaglandin D(2) (K(m); 35.5 nM), leukotriene C(4) (K(m); 3.2 microM) and taurocholate (K(m); 17.6 microM) in a sodium-independent manner. moat1 also transports prostaglandin E(1), E(2), thromboxane B(2), and iloprost but not dehydroepiandrosterone sulfate and digoxin, of which the substrate specificity is similar, but definitively different from those of any other organic anion transporters.

Alternative Splicing↗

PubMed2000

Expression of cyclooxygenase 2 (COX-2) in human glioma and in vitro inhibition by a specific COX-2 inhibitor, NS-398.

The up-regulation of cyclooxygenase 2 (COX-2) expression is a frequent occurrence in a variety of different tumors. In this study, COX-2 protein expression was investigated in 50 glioma and 3 normal brain specimens by immunohistochemistry. Expression of COX-2 protein was observed in all normal brain and glioma specimens by immunohistochemistry, regardless of histological grade. The immunoreactive score was significantly higher in high-grade glioma than low-grade glioma and normal brain specimens. For a subset of these tumors (nine gliomas and three normal brain), Western blot analysis was also performed. COX-2 protein was detected in all specimens by Western blot analysis. The effect of the specific COX-2 inhibitor NS-398 on monolayer cell cultures and three-dimensional glioma spheroids was investigated using U-87MG and U-251MG human glioblastoma cell lines. The proliferation rate was assessed in monolayer cultures. In addition, a growth assay, a migration assay, an apoptosis assay, and a tumor invasion assay were performed in a three-dimensional spheroid culture system. NS-398 was able to reduce the proliferation of monolayer cell cultures, as well as the growth of spheroids and tumor cell migration, in a dose-dependent manner. There was also a moderate increase in the number of apoptotic cells in the treated spheroids. NS-398 did not have an inhibitory effect on tumor invasion in the coculture spheroid system. Our study provides evidence that COX-2 is up-regulated in the majority of high-grade gliomas and that a potential role of COX-2 inhibitors as an adjuvant therapy for brain tumors may exist.

Adult↗

PubMed2000

An F-Box/WD40 repeat-containing protein important for Dictyostelium cell-type proportioning, slug behaviour, and culmination.

FbxA is a novel member of a family of proteins that contain an F-box and WD40 repeats and that target specific proteins for degradation via proteasomes. In fruiting bodies formed from cells where the fbxA gene is disrupted (fbxA(-) cells), the spore mass fails to fully ascend the stalk. In addition, fbxA(-) slugs continue to migrate under environmental conditions where the parental strain immediately forms fruiting bodies. Consistent with this latter behaviour, the development of fbxA(-) cells is hypersensitive to ammonia, the signaling molecule that regulates the transition from the slug stage to terminal differentiation. The slug comprises an anterior prestalk region and a posterior prespore region and the fbxA mRNA is highly enriched in the prestalk cells. The prestalk zone of the slug is further subdivided into an anterior pstA region and a posterior pstO region. In fbxA(-) slugs the pstO region is reduced in size and the prespore region is proportionately expanded. Our results indicate that FbxA is part of a regulatory pathway that controls cell fate decisions and spatial patterning via regulated protein degradation.

Amino Acid Motifs↗

PubMed2000

Novel way of separating polyfluorocarboxylic acids by ion-exclusion chromatography.

Ion-exclusion chromatography has been successfully applied to the separation of a number of polyfluorocarboxylic acids. The separation of various mono- and dibasic polyfluorocarboxylic acids having a different alkyl group was investigated using a polymethacrylate-based weakly acidic cation-exchange resin (TSK gel OApak-A) in the H -form and conductimetric detection. When water was used as the eluent, polyfluorocarboxylic acids could not be resolved. When an aqueous solution of sulfuric acid, benzoic acid, o-phthalic acid, 1,3,5-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, and tartaric acid was used, the separation of polyfluorocarboxylic acids occurred for monobasic ones. While, for fluorine-containing dibasic acids, imperfect separation of peaks occurred. In order to improve their separation, the effect of an addition of organic modifiers such as methanol, 2,2,2-trifluoroethanol and 2H-hexafluoro-2-propanol in the eluent was also investigated.

Carboxylic Acids↗

PubMed2000

FK409, a spontaneous nitric oxide releaser, attenuates allograft vasculopathy in a rat aortic transplant model.

Although systemic administration of NO donors has been shown to attenuate the development of neointimal hyperplasia in the balloon injury model, this strategy has not been tested in a model of allograft vasculopathy. In this study, we investigated the effect of FK409, a spontaneous NO releaser, on the development of allograft vasculopathy, using a rat aortic transplant model. Thoracic aortas from ACI rats were transplanted heterotopically into the abdominal aorta of Wistar-Furth rats. Postoperatively, recipients received FK409 orally every 8 hours from the day of transplantation to the time of euthanization. Morphometric and immunohistochemical analyses were performed on the aortic grafts 8 weeks after transplantation. Control allografts showed severe neointimal hyperplasia, which consists mainly of alpha-actin-containing vascular smooth muscle cells. The FK409-treated allografts showed a dose-dependent reduction (statistically significant compared with the control) in the neointimal thickness as the dose increased from 1 to 10 mg/kg (thrice per day). However, there was no significant difference in the neointimal thickness between groups treated with 10 and with 20 mg/kg. FK409 treatment (10 mg/kg) caused a significant decrease in DNA synthesis (5-bromo-2-deoxyuridine [BrdU] uptake), an increase in DNA fragmentation (terminal deoxynucleotidyltransferase-mediated uridine nick-end labeling [TUNEL]), and upregulation of Fas expression, in the neointimal vascular smooth muscle cells. These data suggest that FK409 attenuates the allograft vasculopathy in a rat aortic transplant model.

Animals↗

PubMed2000

AML1-MTG8 leukemic protein induces the expression of granulocyte colony-stimulating factor (G-CSF) receptor through the up-regulation of CCAAT/enhancer binding protein epsilon.

The t(8;21) translocation is one of the most frequent chromosomal abnormalities associated with acute myeloid leukemia (AML). In this translocation, the AML1 (CBFA2/PEBP2aB) gene is disrupted and fused to the MTG8 (ETO) gene. The ectopic expression of the resulting AML1-MTG8 fusion gene product in L-G and 32Dcl3 murine myeloid precursor cells stimulates cell proliferation without inducing morphologic terminal differentiation into mature granulocytes in response to granulocyte-colony stimulating factor (G-CSF). This study found that the ectopic expression of AML1-MTG8 elevates the expression of the G-CSF receptor (G-CSFR). Analysis of the promoter region of the G-CSFR gene revealed that up-regulation of G-CSFR expression by AML1-MTG8 does not depend on the AML1-binding sequence, but on the C/EBP (CCAAT/enhancer binding protein) binding site. The results suggest that the overproduction of G-CSFR is at least partly mediated by C/EBPepsilon, whose expression is activated by AML1-MTG8. The ectopic expression of G-CSFR in L-G cells induced cell proliferation in response to G-CSF, but did not inhibit cell differentiation into mature neutrophils. Overexpression of C/EBPepsilon in L-G cells also stimulated G-CSF-dependent cell proliferation. High expression levels of G-CSFR were also found in the leukemic cells of AML patients with t(8;21). Therefore, G-CSF-dependent cell proliferation of myeloid precursor cells may be implicated in leukemogenesis.

Animals↗

PubMed2000

High-precision measurement of the left-right Z Boson cross-section asymmetry.

We present a measurement of the left-right cross-section asymmetry ( A(LR)) for Z boson production by e(+)e(-) collisions. The measurement includes the final data taken with the SLD detector at the SLAC Linear Collider during the period 1996-1998. Using a sample of 383 487 Z decays collected during the 1996-1998 runs we measure the pole value of the asymmetry, A(0)(LR), to be 0.150 56+/-0.002 39 which is equivalent to an effective weak mixing angle of sin (2)straight theta(eff)(W) = 0.231 07+/-0.000 30. Our result for the complete 1992-1998 data set comprising approximately 537 000 Z decays is sin (2)straight theta(eff)(W) = 0.230 97+/-0.000 27.

Journal Article↗

PubMed2000

Determination of N-acetyl- and N-glycolylneuraminic acids in gangliosides by combination of neuraminidase hydrolysis and fluorometric high-performance liquid chromatography using a GM3 derivative as an internal standard.

A highly sensitive method for quantification of sialic acids in gangliosides was developed. The sialic acids, released by hydrolysis of gangliosides, were converted to fluorescent derivatives with 1,2-diamino-4,5-(methylenedioxy)benzene (DMB) and separated on a reversed-phase C18 column with an isocratic elution. As little as 0.1-1.0 nmol of sialic acid in ganglioside was quantified. The use of acetate buffer instead of water in the mobile phase could prevent damage on the column and reduce background peaks derived from the reagents. When gangliosides were subjected to acid hydrolysis, the velocity of hydrolysis varied depending on their structures and a part of the sialic acid liberated decomposed with prolonged heating time. Therefore gangliosides were hydrolyzed by Arthrobacter ureafaciens neuraminidase in the presence of sodium cholate after addition of an internal standard. For the internal standard, GM3 with N-propionylneuraminic acid (GM3(NeuPr)) was synthesized from GM3(NeuAc) by N-deacylation followed by N-propionylation. Folch partition was used to decrease lipophilic materials included in the sample, and the sialic acids released were recovered from the upper phase. The present method has a satisfactory sensitivity in the simultaneous quantification of NeuAc and NeuGc in purified gangliosides as well as in crude lipid fractions containing a variety of gangliosides.

Carbohydrate Sequence↗

PubMed2000

Investigation of possible involvement of several genes related to development of hepatocarcinogenesis in rats.

A comparative study on the possible involvement of several genes in the susceptibility of chemical carcinogenesis was carried out using carcinogen-resistant DRH rat and -sensitive Donryu and F344 rats. Previously, we observed that the induction of glutathione S-transferase placental form (GST-P) in the liver of Donryu rats by 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB) was significantly greater than that of DRH rats. In the present study, we tentatively determined base sequences of the enhancer region including GPE-I and GPE-II (GST-P enhancers I and II) of GST-P genes of DRH, Donryu and F344 rats, but we did not observe any nucleotide polymorphism around these regions. Furthermore, the mRNA levels of silencer binding protein (NFA-1) for the GST-P promoter of rat liver were also similar in the DRH and Donryu rats. Since clonal expansion of putative preneoplastic GST-P-positive foci in the DRH rat liver was significantly suppressed during 3'-Me-DAB administration, we examined whether two opposite growth controlling factors, TGF-alpha and TGF-beta, may participate in such suppression of growth. It was supposed that mannose 6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R), at least in part, activates TGF-beta preproprotein. However, we observed that the levels of M6P/IGF2R mRNA in the livers of DRH were not higher than those of Donryu rats after being fed 3'-Me-DAB for 8 weeks. Another important factor in the carcinogenesis is insulin-like growth factor II itself. Although liver tumors induced by 3'-Me-DAB in F344 had high levels of IGF-II mRNA, little IGF-II gene expression existed in normal adult livers of Donryu, F344 and DRH rats. High levels of IGF-II mRNA were detected similarly in the livers of neonates from all these three strains of rats. Finally, we detected a significant increase of AFP (alpha-fetoprotein) mRNA in the livers of Donryu rats around 6 to 8 weeks from the start of 3'-Me-DAB feeding, which is in parallel with detrimental effects of this carcinogen on these rats. A reduced induction of AFP mRNA was observed in DRH rats under the same conditions. Further study will be needed to explain the lower tumor susceptibility in the DRH rat.

Animals↗

PubMed2000

Expression of the 37-kDa laminin binding protein in murine lung tumor cell correlates with tumor angiogenesis.

Expression of the 37-kDa laminin binding protein (37LBP), a precursor protein of the 67-kDa laminin receptor, correlates well with the biological aggressiveness of cancer cells. Previously, we have established murine lung cancer cell lines T11 and T15, in which 37LBP expression was remarkably diminished, and reported that the mean survival time of the T11 and the T15-recipients was significantly prolonged compared with that of the control cell lines (P29 and T42). In the present study, immunohistochemical findings of the tumors demonstrated that the microvessel density in the T11 (28. 1+/-7.2/mm(2)) and in the T15 tumor (29.7+/-6.5/mm(2)) were significantly lower than that observed in P29 (46.3+/-8.7/mm(2)) or in T42 (50.5+/-4.4/mm(2)). Expression of vascular endothelial growth factor (VEGF) was repressed in T11 and T15 compared with its expression in P29 and T42. It was also shown that conditioned media of T11 and T15 cells exhibited significantly reduced proliferation and migration of the capillary endothelial cells. These results suggest that decreased expression of 37LBP in antisense-RNA transfectant may relate to its low tumorigenicity, and that this effect may be partly caused by the diminished tumor angiogenesis of murine lung cancer.

Animals↗

PubMed2000

Girl with accelerated growth, hearing loss, inner ear anomalies, delayed myelination of the brain, and del(22)(q13.1q13.2).

We report on an 18-month-old Japanese girl with 46,XX,del(22)(q13.1q13.2). To our knowledge, this is the first report of a case of interstitial deletion of a 22q13.1-q13.2 segment. Clinical features included hearing loss accompanied by inner ear anomalies, hypotonia and minor anomalies, such as a long philtrum, full eyelids, epicanthus, left transverse palmar crease and psychomotor developmental delay. Despite the chromosomal deletion, her physical growth was accelerated: her height was between the 75th and 90th percentiles for her age. Her brain MRI showed signs of delayed myelination. The three-dimensional MRI of the inner ear showed abnormalities of the cochlea and vestibule in both ears. Clinical features of the patient are similar to those of a patient with a del(22)(q13.1q13.33) karyotype previously reported by Romain et al.

Abnormalities, Multiple↗

PubMed2000

Amplification and over-expression of the AIB1 nuclear receptor co-activator gene in primary gastric cancers.

Our analysis of chromosomal aberrations in primary gastric cancers using comparative genomic hybridization has revealed novel, high and frequent copy number increases in the long arm of chromosome 20, indicating that this region contains novel amplified genes involved in gastric cancer progression. AIB1, a member of the steroid receptor co-activator-1 family, has been cloned on 20q12 as a candidate target gene for this amplification in human breast cancers. In this study, we examined the numbers of AIB1 copies as well as their expression and relation to clinico-pathological features in 72 primary gastric cancers. AIB1 amplification was observed in 7% and over-expression in 40% of the specimens. AIB1 amplification always coincided with its over-expression, but several cases showed AIB1 over-expression without amplification, suggesting that expression of AIB1 is regulated not only by gene amplification but also by other mechanisms, such as transcriptional activation, in human gastric cancer. Gastric cancers with AIB1 amplification showed extensive lymph node metastases, liver metastases and poorer prognosis compared to those without amplification. Our results suggest that amplification and over-expression of AIB1 are likely to increase the number of malignant phenotypes of gastric cancers and that it can be expected to be useful as a marker of poor prognosis.

Adult↗

PubMed2000

In vivo conformation of mitochondrial DNA revealed by pulsed-field gel electrophoresis in the true slime mold, Physarum polycephalum.

Pulsed-field gel electrophoresis (PFGE) was used to examine the in vivo and in vitro conformations of Physarum polycephalum mitochondrial DNA (mtDNA). We used plugs containing isolated mitochondria, isolated mitochondrial nucleoids (mt-nuclei), and isolated mtDNA, in addition to whole cells. The mtDNA contained in the myxamoebae, plasmodia, isolated mitochondria, and isolated mt-nuclei was circular, but most of the isolated mtDNA had been site-specifically fragmented and linearized during DNA preparation and storage under low ionic strength conditions. Restriction mapping of Physarum mtDNA by the direct digestion of the isolated mt-nuclei from two different strains, DP89 x AI16 and KM88 x AI16, resulted in the circular form. A linear mitochondrial plasmid, mF, is known to promote mitochondrial fusion and integration of itself into the mtDNA in Physarum. Linearization of mtDNA by the integration of the mF plasmid was demonstrated when we used PFGE to analyze isolated mitochondria from the plasmodial strain DP89 x NG7 carrying the mF plasmid (mF+). The PFGE system can be used not only to determine whether the form of mtDNA is linear or circular but also to analyze the dynamic conformational changes of mtDNA.

Animals↗

PubMed2000

Inhibition of HIV-1 replication by a new type of circular dumbbell RNA/DNA chimeric oligonucleotides.

We have designed a new class of oligonucleotides, "dumbbell RNA/DNA chimeric phosphodiesters," containing two alkyl loop structures with RNA/DNA base pairs [sense (RNA) and antisense (DNA)] in the double helical stem. The reaction of nicked (NDRDON-gag-AUG) and circular (CDRDON-gag-AUG) dumbbell RNA/DNA chimeric oligonucleotides with RNaseH gave the corresponding antisense phosphodiester oligonucleotide together with the sense RNA cleavage products. The liberated antisense phosphodiester oligodeoxynucleotide was bound to the target RNA. The circular dumbbell RNA/DNA chimeric oligoncleotide showed more nuclease resistance and cellular uptake than the linear antisense phosphorothioate oligodeoxynucleotide (S-ODN-gag-AUG) and nicked dumbbell RNA/DNA chimeric oligonucleotide. The CDRDON-gag-AUG with an AUG initiation codon sequence, as the target of the HIV-1 gag-gene (779-801), was synthesized and tested for inhibitory effects using peripheral blood mononuclear cells. The circular dumbbell RNA/DNA chimeric oligonucleotide (CDRDON-gag-AUG) showed highly inhibitory effects compared to the antisense phosphorothioate oligonucleotide (S-ODN-gag-AUG), indicating sequence-specific inhibition of HIV-1 replication without the inhibition of reverse transcriptase and/or the viral entry process such as antisense phosphorothioate oligonucleotides.

Base Sequence↗

PubMed2000

Lymph node metastases identified with mediastinoscopy in a patient with superficial carcinoma of the esophagus.

Superficial esophageal cancers limited to the lamina propria are not associated with lymph node metastases. Mediastinoscopic transhiatal esophagectomy was planned in a patient with widespread superficial cancer of the midthoracic esophagus. Sampling of the upper mediastinal lymph nodes revealed metastases. The operation was converted to a transthoracic esophagectomy with radical lymphadenectomy. Histopathologic examination of the resection specimen showed three metastatic lymph nodes, despite local invasion limited to the lamina propria. This is the first report of a patient with superficial esophageal cancer and lymph node metastases.

Carcinoma, Squamous Cell↗