Biomedical subjects

A Naito

Publications and source records attributed to A Naito.

At least 109 records · Page 6Linked to original sources

PubMed1994

The cortico-nigral projection in the rat: an anterograde tracing study with biotinylated dextran amine.

The projection from the cortex to the substantia nigra (SN) in the rat was studied using the biotinylated dextran amine (BDA) anterograde tracing method. Injections of BDA into the prefrontal cortex consistently yielded labeling of the thin nerve fibers with small boutons in the SN pars compacta (SNc) and the pars reticulata (SNr). The cortico-nigral projection had a loose medio-lateral and rostro-caudal arrangement. Injections of BDA into the precentral lateral, the parietal, the temporal, and the occipital cortices resulted in sparse or no labeling of boutons in the SN. The density of boutons in the most heavily labeled region of the SN was 0.23/10(3) micron3. For comparison, similar measurement was performed in the cortico-striatal projection. The density of the boutons in the the neostriatum was 4.9/10(3) micron3. This study indicates that the entire prefrontal cortex projects to the SNc and SNr and that the terminal density of this projection is much less than the cortico-striatal projection.

Animals↗

PubMed1994

Expression of cripto in human pancreatic tumors.

The expression of cripto gene product was examined immunohistochemically in 45 surgically resected pancreatic tumors, including 32 invasive ductal carcinomas, 4 intraductal papillary adenocarcinomas, 4 intraductal papillary adenomas, 2 mucinous cystadenomas, 2 islet cell tumors, and one solid and cystic tumor, and compared with that in 32 areas of accompanying chronic pancreatitis present in the cases of invasive ductal carcinomas and 5 non-tumorous areas of pancreas without pancreatitis. All pancreatic ductal tumors including adenomas and carcinomas showed positive staining with no difference in terms of staining intensity among intraductal tumors and invasive carcinomas with or without mucin hypersecretion. Islet cell tumors were positively stained but the solid and cystic tumor was negative. Duct epithelial cells and acinar cells were negative but islet cells were positive in the pancreas tissues without pancreatitis. Cells arranged in duct-like structures in areas of accompanying chronic pancreatitis were positively stained. The results suggest that cripto expression might be associated with a growth advantage of tumor cells and also with differentiation to form duct-like structures.

Biomarkers, Tumor↗

PubMed1994

Antioxidative action of the nitrovasodilator nicorandil: inhibition of oxidative activation of liver microsomal glutathione S-transferase and lipid peroxidation.

Antioxidative effects of the nitrovasodilator nicorandil (SG-75) and denitrated SG-75 (SG-86) were examined in vivo and in vitro. When the isolated rat liver was reperfused with Krebs-Henseleit solution after a 90-min ischemia, microsomal GSH S-transferase activity was increased significantly by oxidative modification of the sulfhydryl group of the enzyme. The increase in the transferase activity after ischemia/reperfusion was depressed by SG-75 but not by SG-86. Furthermore, only SG-75 significantly inhibited lipid peroxidation and the activation of microsomal GSH S-transferase induced by hydrogen peroxide treatment of liver microsomes. These data indicate that SG-75 has an antioxidative action and the nitro group of SG-75 may play a critical role for this action.

Animals↗

PubMed1994

Electrophysiological studies of the biceps brachii activities in supination and flexion of the elbow joint.

Activities of the biceps brachii (long head: BiL, short head: BiS) on the elbow joint were studied using an electrical neuromuscular stimulation (ENS) and an electromyography (EMG). In ENS study, ENS to BiL or BiS was performed in seven volunteers. Before ENS, the volunteer relaxed the upper extremity on a table with the elbow extended and the forearm pronated. Then ENS-induced movements of the upper extremity were examined. Movements of elbow flexion and forearm supination were induced simultaneously by ENS to BiS in all volunteer and by ENS to BiL in six volunteers. ENS to BiL of one volunteer resulted in only elbow flexion. In EMG study, averaged EMGs of BiL and BiS during a to-and-fro motion from prone to supine of the forearm with holding a load were analyzed in eight volunteers. The volunteer acted the movements with keeping the elbow joint in different angles. Although an increase and a decrease of EMG activities in BiL and BiS were observed accompanied by the degree of forearm supination, patterns of changes in quantities of EMG activities to changing elbow angles varied from individual to individual. These findings seem to indicate that each human subject has an individual use of the biceps brachii for supination movements, while the action of the muscle on the elbow joint is similar among the subjects.

Adult↗

PubMed1994

Functional electrical stimulation (FES) to the biceps brachii for controlling forearm supination in the paralyzed upper extremity.

Control of forearm supination using the functional electrical stimulation (FES) to the biceps brachii was studied in a C4 quadriplegic patient. As a result of FES to the biceps brachii, and the other elbow flexors and extensors, supination was induced in maintenance of the elbow in the maximum flexion and extension, respectively. Although a range of the movements was still small and limited, these findings indicated a possibility of FES to the biceps brachii for controlling supination in paralyzed upper extremities.

Adult↗

PubMed1994

Study on the elbow movement produced by functional electrical stimulation (FES).

Functional electrical stimulation (FES)-induced movements of the upper extremity using the electromyography (EMG)-based stimulation data, which were created on the basis of EMG analysis of elbow flexion and extension in a normal human subject, were examined. As a result of the FES to the elbow flexors and extensors in another normal subject, smooth and reproducible elbow flexion and extension were controlled. This result seems to indicate not only an advantage of EMG-based stimulation data in the FES but also a great potential of FES as a new technique for the functional anatomy of the human extremities.

Elbow Joint↗

PubMed1994

Patients' reactions to angioplasty: realistic or not?

BACKGROUND: A major problem limiting the success of angioplasty is the high restenosis rate. In addition, coronary artery disease is an ongoing process requiring lifestyle changes to prevent disease progression. OBJECTIVE: To examine patient concerns and risk factor modification behaviors during early recovery from angioplasty. Specific attention was directed to: (1) expectation of restenosis, (2) occurrence of angina, (3) achievement of expected benefits, (4) tension/anxiety levels, (5) self-efficacy for and actual performance of needed lifestyle changes. METHODS: For this descriptive study the Self-Report of Recovery (a project-derived questionnaire) and the Profile of Mood States were mailed to 54 patients at 1, 6, and 12 weeks of recovery. The study group comprised 37 men and 17 women (mean age, 57 years) who had undergone first-time successful angioplasty at a midwestern medical center. At 12 weeks 78% remained. RESULTS: A majority of patients did not expect restenosis to occur. At 3 months 83% reported that they were angina-free, 90% reported that they would repeat the procedure if needed, all scores on the tension/anxiety scale were normal, and 86% had achieved some benefits they had expected. Most expressed high confidence in their ability to reduce risk factors, with 90% reporting initiation of at least one lifestyle change. CONCLUSION: We concluded that patients had positive feelings about their angioplasty experience and were not overly concerned about restenosis.

Adult↗

PubMed1994

[Catheter intervention to venous system using expandable metallic stents].

Superior vena cava syndrome mainly associated with malignant tumors, is usually resistant to any therapy. Although mechanical dilation of narrowed lumen is ideal for relief of symptoms, conventional balloon angioplasty has not been effective method. Surgical intervention is not a good choice in patients with advanced malignant tumors. Recently developed expandable metallic stents have been adopted to superior vena cava syndrome with good results. In this article, characteristics of expandable metallic stents is reviewed, and our experience of expandable metallic stents (Gianturco stent and Wallstent) in venous system is indicated. In addition, percutaneous insertion of inferior vena cava filter (Greenfield filter) is also mentioned.

Adult↗

PubMed1993

A high-resolution solid-state 13C-NMR study on [1-13C]Ala and [3-13C]Ala and [1-13C]Leu and Val-labelled bacteriorhodopsin. Conformation and dynamics of transmembrane helices, loops and termini, and hydration-induced conformational change.

We have recorded 100.7-MHz high-resolution solid-state 13C-NMR spectra of [3-13C]Ala, [1-13C]Ala-labelled, Leu-labelled and Val-labelled bacteriorhodopsin (bR), to analyze the conformation and dynamics of transmembrane alpha helices and hydration-induced conformational changes. We assigned the 13C-NMR signals of these 13C-labelled amino acid residues to portions of the transmembrane alpha helices, loops and N-terminus and C-terminus, based on the conformation-dependent 13C chemical shift. The assignment of peaks to the transmembrane alpha helices is straightforward in view of the characteristic 13C chemical shifts of the C beta and carbonyl carbons, referred to the data of the model system. The signals of the transmembrane alpha helices were further divided into three or four peaks which are ascribed to either a dispersion of torsion angles of the alpha helices or variation of environments around the helices. In addition, we found that conformation of the N-terminus and C-terminus of bR is virtually the random-coil form which undergoes rapid reorientational motion in the hydrated system. Further, we show that the higher-order (secondary and/or tertiary) structure of bR is influenced by the hydration/dehydration process of the purple membrane, as viewed from the peak profile of the Ala C beta 13C signals. This change of structure occurs between relative humidities of 2% and 4%, consistent with the shift of the absorption maxima of retinal, which arise from the protonation/deprotonation processes of the Schiff base. In contrast, no such change of the carbonyl signals occurs for the Leu, Val and Ala residues. For the latter two residues, some spectral changes were noted at the stage of full hydration.

Alanine↗

PubMed1993

Increase in liver microsomal glutathione S-transferase activity by phenobarbital treatment of rats. Possible involvement of oxidative activation via cytochrome P450.

The possible involvement of oxidative activation of liver microsomal glutathione (GSH) S-transferase by the cytochrome P450 system was investigated. When rats were given phenobarbital (PB) intraperitoneally for 3 days, liver microsomal GSH S-transferase activity was stimulated 1.3-1.4-fold and the effect of PB on the transferase was potentiated by combination with a catalase inhibitor, 3-amino-1,2,4-triazole. Immunoblotting of microsomal proteins from PB-treated rats with anti-microsomal GSH S-transferase antibody after SDS-PAGE showed the presence of a dimer of the transferase. When microsomal suspensions prepared from PB-treated rats were placed on ice without GSH, the microsomal GSH S-transferase activity gradually increased with time and reached 200% of the initial level at 3 hr when activation of the transferase by N-ethylmaleimide was lost. The time-dependent increase in GSH S-transferase activity in PB-treated microsomes was prevented by addition of 0.1 mM GSH. The increase in microsomal GSH S-transferase activity by NADPH was depressed by cytochrome P450 inhibitors such as SKF 525-A (2-diethylaminoethyl-2,2-diphenylvalerate), metyrapone or isoniazid in agreement with the concomitant decrease in generation of hydrogen peroxide in microsomes. These results indicate that the increase in GSH S-transferase activity in liver microsomes by PB treatment of rats is due to the oxidative modification of the enzyme by reactive oxygen species which are concomitantly increased following induction of cytochrome P450.

Amitrole↗

PubMed1993

Oxidative stress-induced activation of microsomal glutathione S-transferase in isolated rat liver.

The activation of microsomal glutathione (GSH) S-transferase in isolated rat liver by oxidative stress was investigated using both ischemia/reperfusion and perfusion with hydrogen peroxide. When the isolated liver was reperfused for 30 min and 60 min after 90 min ischemia, microsomal GSH S-transferase activity, but not cytosolic transferase activity, was increased 1.2-fold and 1.3-fold, respectively. In addition, microsomal GSH peroxidase activity was also significantly increased after 60 min reperfusion following ischemia. The increase in microsomal GSH S-transferase activity by ischemia/reperfusion was reversed by dithiothreitol. When N-ethylmaleimide, which activates microsomal GSH S-transferase by covalent binding to the cysteine residue of the enzyme, was incubated with microsomes, transferase activity was increased to 526% in control microsomes and to 399% in liver that underwent ischemia/reperfusion liver. These data indicate that microsomal GSH S-transferase is activated by ischemia/reperfusion of the liver by means of disulfide bond formation. When rats were pretreated with a catalase inhibitor 3-amino-1,2,4-triazole for 6 weeks, microsomal GSH S-transferase activity was increased 1.4-fold by ischemia/reperfusion, corresponding to a 1.8-fold increase as compared to the non-perfused liver of untreated rats. Perfusion of the isolated liver with hydrogen peroxide (1 mM, 15 min) also caused a significant increase in microsomal GSH S-transferase activity with a concomitant decrease in GSH content, confirming that liver microsomal GSH S-transferase in rats was activated in vivo by oxidative stress.

Animals↗

PubMed1993

A specific host factor binds at a cis-acting transcriptionally silent locus required for stability control of yeast plasmid pSR1.

A cis-acting locus, Z, of plasmid pSR1 functions in stable maintenance of the plasmid in the native host, Zygosaccharomyces rouxii. The Z locus was shown to be located in a 482 bp sequence in the 5' upstream region of an open reading frame, P, by subcloning various DNA fragments in a plasmid replicating via the ARS1 sequence of the Saccharomyces cerevisiae chromosome. Northern analysis revealed that the Z region is not transcribed in either the native host Z. rouxii or the heterologous host S. cerevisiae. The Z region is protected from micrococcal nuclease attack in Z. rouxii but not in S. cerevisiae, its protection depending on the product of the S gene encoded by pSR1. Gel retardation assays suggested that a factor present in nuclear extracts of Z. rouxii cells, irrespective of the presence or absence of a resident pSR1 plasmid, binds to a 111 bp RsaI-SacII sequence in the Z region. These findings suggest that a host protein binds to the Z locus and that the S product interacts with this DNA-protein complex and stabilizes pSR1.

Base Sequence↗

PubMed1993

Clinical value of enzyme immunoassay of epidermal growth factor receptor in human breast cancer.

Epidermal growth factor receptor (EGFr) levels were analyzed in 140 primary breast cancer specimens by immunohistochemical assay (ICA), competitive binding assay (BA), or enzyme immunoassay (EIA). Thirty-nine of 118 specimens (33.1%) were scored as positive by ICA, 30 of 116 (25.9%; cut-off level 10 fmol/mg protein) by BA, and 31 of 80 (38.9%: cut-off level 5 fmol/mg protein) by EIA. Agreement on EGFr status was 72.3% (68/94) between ICA and BA, 77.0% (57/74) between BA and EIA, and 73.8% (59/80) between EIA and ICA. These discrepancies are based on assay differences and the heterogeneous distribution of cancer cells within specimens. Regardless of the assay method used, EGFr status had a significantly negative correlation with estrogen receptor status. Although EGFr-ICA and BA status had no relationship with prognosis, patients with medium and high EGFr-EIA level tumors (over 5 fmol/mg protein) had shorter relapse-free periods than those with low level tumors. However, the prognostic value of positive EGFr-EIA status was weaker than that of c-erbB-2 overexpression.

Adult↗

PubMed1993

New HIV plaque titration; application to the assay of neutralizing antibody.

A simple, sensitive and accurate plaque assay was developed using HPB-Ma, a variant of the human T-cell line HPB-ALL, which becomes adherent to the substratum after infection with an amphotropic murine sarcoma virus (MSVa). The simplicity of this novel plaque assay allowed us to examine a large number of serum samples from patients with HIV infection for neutralizing antibody activity against two human immunodeficiency virus type-1 (HIV-1) strains. During the progression of clinical disease, the neutralizing activity in the sera from two individual patients remained unchanged or increased. A patient with a known time of HIV infection produced cross-neutralizing antibody at 25-34 weeks. The neutralizing activity in the sera from 17 asymptomatic carriers, four patients with AIDS-related complex and four AIDS patients was also examined and was found to be unrelated to the clinical stage.

Cell Line↗

PubMed1993

Analysis of oncogenes and tumor suppressor genes in human breast cancer.

Oncogenes (c-erbB-2, c-myc, and some genes linked to the 11q13 lesion), tumor suppressor genes (retinoblastoma gene, p53) and an antimetastatic gene (nm23/nucleoside diphosphate kinase) play important roles in breast cancer progression. Amplification of c-erbB-2, c-myc, and int-2, and expression of RB, p53(mutant), and NDP kinase were determined in 77 primary breast cancer specimens. nm23-H1 allelic loss was also studied. c-erbB-2 and c-myc amplification, loss of RB expression, p53(mutant) expression, and nm23-H1 allelic loss were also found in non-invasive carcinoma. int-2 amplification was significantly correlated with lymph node status (P = 0.02) and a significant association was found between p53(mutant) expression and tumor size (P = 0.04). c-erbB-2 amplification was strongly associated with disease-free and overall survival in multivariate analysis (P = 0.002). All of the c-erbB-2 amplified cases and all but one of the int-2 amplified cases in node-positive patients had relapsed within 2 years post resection. The cancer cells may acquire new proliferative pathways sequentially as a result of multiple genetic alterations which enable them to bypass the estrogen-dependent proliferation.

Breast Neoplasms↗

PubMed1992

Automatic elimination of unnecessary bacterial sequences from yeast vectors.

Most vectors for Saccharomyces cerevisiae are shuttle vectors which can be both propagated and selected in Escherichia coli. The DNA segments, however, which are required for propagation in E. coli are unnecessary and moreover toxic in S. cerevisiae. To delete these harmful DNA fragments from the vector after it is introduced into S. cerevisiae cells, we propose a specific gene conversion mechanism of a yeast plasmid, pSR1. Plasmid pSR1 has a pair of inverted repeats (IRs) that divides the plasmid molecule into two unique regions. Intramolecular recombination frequently occurs at a pair of specific recombination sites in IRs catalyzed by recombinase R, encoded by a pSR1 plasmid gene. This R-mediated recombination is often accompanied by gene conversion in IRs. Thus, a 2.1-kb pBR322 sequence for the E. coli host ligated into one of the IRs of a composite plasmid was automatically and effectively eliminated when the plasmid was introduced into S. cerevisiae cells.

DNA, Bacterial↗

PubMed1992

A high-resolution solid-state 13C-NMR study on crystalline bovine heart cytochrome-c oxidase and lysozyme. Dynamic behavior of protein and detergent in the complex.

We have recorded 100.6-MHz high-resolution solid-state 13C-NMR spectra of crystalline cytochrome-c oxidase from bovine heart muscle and hen egg-white lysozyme, to compare conformation and dynamics of a typical membrane-protein complex with those of lysozyme. The absence of severe interference with the solid-state 13C-NMR spectra, from both the line broadenings from paramagnetic centers and overlapping of intense detergent signals, provided spectral resolution of 13C-NMR feature of cytochrome-c oxidase crystals comparable to that of lysozyme crystal and better than that of dissolved or lyophilized samples. In fact, the observed peak intensities of the polar heads of the detergents BL8SY and Brij 35 were only about 10% and 3% of the anticipated values, respectively. The dynamic behavior of the backbone and side chains of cytochrome-c oxidase was compared with that of lysozyme on the basis of the 13C spin-lattice relaxation times (T1): the backbone of the cytochrome-c oxidase turned out to be more flexible than that of lysozyme. Molecular motions of the detergent molecules attached to the proteins are found to be highly heterogeneous. Detergent molecules undergo rapid tumbling motions in the crystals in about 10 ns as detected by T1. In addition to rapid motions, slow motions were detected by 1H spin-lattice relaxation time in the rotating frame (TH1 rho) and cross-polarization time (TCH), together with data from static spectra, indicating that the aliphatic portion of the detergent interacts more strongly with hydrophobic protein surfaces than do the polar heads.

Crystallography↗

PubMed1992

Similarity of the genomic structure between the two members in a new family of heparin-binding factors.

By differential hybridization of cDNA libraries from Fv-1 restrictive and non-restrictive somatic mutant mouse cells, we isolated a cDNA clone specifically present in the Fv-1 restrictive cells. Its sequence was found identical to that of heparin-binding growth-associated molecule or pleiotrophin (HB-GAM/PTN). We report here its genomic organization which has not been yet reported. Although the exon organization was similar to that of midkine, another member of the same family of heparin-binding factors, the sizes of introns were much larger and occupied more than a three-fold larger chromosomal region than midkine. As its introduction into Fv-1 non-restrictive cells failed to confer the Fv-1 restrictive character, HB-GAM/PTN is probably unrelated to Fv-1 restriction.

Animals↗