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Biomedical subjects

Y Yanagita

Publications and source records attributed to Y Yanagita.

At least 19 recordsLinked to original sources
PubMed2001

The seven amino acids of human RAMP2 (86) and RAMP3 (59) are critical for agonist binding to human adrenomedullin receptors.

When co-expressed with a receptor activity-modifying protein (RAMP) accessory protein, calcitonin receptor-like receptor (CRLR) can function as a calcitonin gene-related peptide receptor (CRLR-RAMP1) or an adrenomedullin (AM) receptor (CRLR-RAMP2/3). Here we report on the structural domain(s) involved in selective AM binding that were examined using various RAMP chimeras and deletion mutants. Co-expression of chimeric RAMPs and CRLR in HEK293 cells revealed that residues 77-101, situated in the extracellular N-terminal domain of human RAMP2 (hRAMP2), were crucial for selective AM-evoked cAMP production. More detailed analysis showed that deletion of hRAMP2 residues 86-92 significantly attenuated high-affinity (125)I-AM binding and AM-evoked cAMP production despite full cell surface expression of the receptor heterodimer and that deletion of hRAMP3 residues 59-65 had a similar effect. There is little sequence identity between hRAMP3 residues 59-65 and hRAMP2 residues 86-92; moreover, substituting alanine for Trp(86) (Ala(87)), Met(88), Ile(89), Ser(90), Arg(91), or Pro(92) of hRAMP2 had no effect on AM-evoked cAMP production. It thus seems unlikely that any one amino acid residue is responsible for determining selective AM binding or that AM binds directly to these peptide segments. Instead these findings suggest that the respective seven-amino acid sequences confer selectivity either by directly contributing to the structure of ligand binding pocket or by allosteric modulation of the conformation of CRLR.

Adrenomedullin↗
PubMed2001

Clinicopathological study of unilateral multiple breast cancer.

BACKGROUND: The tendency for breast cancer to form multiple lesions is important to consider when planning breast-conserving surgery. However, many unknowns remain regarding the pathology and prognosis of multiple breast cancer, and therefore it is clinically significant to investigate its clinicopathological properties. METHODS: Over the past 25 years, in the period between April 1972 and March 1997, we investigated the clinicopathological findings including the 5-year and 10-year survival rates of 66 patients treated for unilateral multiple breast cancer. RESULTS: Of the total of 1,334 female patients with unilateral breast cancer who underwent curative surgery at our hospital, we identified 66 (5.0%) patients with unilateral multiple cancer. The incidence of such cancer has been higher in recent years. Of the 66 patients, 50 (75.8%) were premenopausal, and the remaining patients were postmenopausal, but multiple cancer among postmenopausal women is a recent phenomenon. The ER positivity rate of the main lesion in patients with multiple breast cancer was 69.2% and that of PgR was 50.0%. The 5-and 10-year overall survival rate in all 66 patients with multiple breast cancer was 90.8% and 79.7%, respectively. CONCLUSION: In the past, multiple breast cancer was frequently identified in premenopausal women. However, the current findings indicate that its incidence among postmenopausal women has increased in recent years. In addition, prognoses were comparable for patients with multiple or solitary breast cancer, a relevant finding in the planning of breast-conserving surgery.

Adult↗
PubMed2000

Molecular analysis of the h-warts/LATS1 gene in human breast cancer.

Loss of heterozygosity (LOH) on chromosome 6q is often observed in breast cancer, suggesting the existence of a putative tumor suppressor. Recently, a human homolog of the Drosophila warts tumor suppressor gene, h-warts/LATS1, was identified and mapped at chromosome 6q24-25.1. Mutation analysis of the h-warts/LATS1 was performed using 25 breast cancer tissues by RT-PCR SSCP analysis. Although LOH of the h-warts/LATS1 was found in one patient, no mutations were found. Two polymorphisms were found, but neither of them caused amino acid substitutions. Further investigations are necessary to elucidate the role of the h-warts/LATS1 gene in the carcinogenesis of breast cancer.

Breast Neoplasms↗
PubMed2000

[Anesthetic management of a patient with amyotrophic lateral sclerosis].

A 49-year-old male with amyotrophic lateral sclerosis (ALS) was scheduled for gastrectomy. Anesthetic management was performed under general anesthesia with sevoflurane and epidural anesthesia with lidocaine. He showed increased response to vecuronium under monitoring of neuromuscular block. But he responded favorably to anticholineesterase. He had little pain and showed no progress in neurological symptoms in the postoperative period. Neuromuscular monitoring is essential in administrating non-depolarizing neuromuscular blocking agents to patients with ALS, and epidural anesthesia may be useful for perioperative management of patients with ALS.

Amyotrophic Lateral Sclerosis↗
PubMed2000

[Weekly administration of paclitaxel for advanced or metastatic breast cancer--short-course premedications for outpatients].

A phase II trial has demonstrated that paclitaxel (210 mg/m2/3 hr) showed a 33.3% response rate among anthracycline-resistant breast cancer patients in Japan. Recently, weekly dosing of paclitaxel has been demonstrated to be a well-tolerated, feasible and effective administration schedule. Standard premedication is commonly administered prior to treatment with paclitaxel. However, this regimen requires dexamethasone administration beginning at 12 to 14 hours prior to paclitaxel, which would not be convenient for outpatients. In this study, paclitaxel was administered by 1 hour intravenous infusion at a dose of 80 mg/m2 every week. Administration was continued for 3 weeks with a 1 week rest. A short course premedication schedule consisted of dexamethasone 20 mg i.v. (diluted in 50 ml normal saline, 1 hour prior to paclitaxel), and oral diphenhydramine 50 mg, H2-antagonist and anti-emetic agent i.v. (diluted in 50 ml normal saline, 30 minutes prior to paclitaxel). A total of 14 outpatients were enrolled in the study. There were 10 partial responders and no complete responders, and the overall response rate was 71.4%. No hypersensitivity reactions were observed, and grade 3/4 leukopenia occurred in 43% (6/14). Allopecia was observed in 4 patients, and peripheral neuropathy in 1 patient (both grade 1). Weekly administration of paclitaxel is effective and well-tolerated in patients with advanced or metastatic breast cancer, with a minimum of peripheral neuropathy. In addition to the above, no hypersensitive reaction in the short course premedication schedule suggests that this administration schedule is feasible for outpatients.

Adult↗
PubMed1998

Primary culture of cells from hyperfunctioning thyroid adenoma with an activating mutation of G alphas.

We analyzed cultured cells from hyperfunctioning thyroid adenoma and its surrounding thyroid tissue from a Japanese woman and determined the nucleotide sequences of genes encoding the alpha subunit of the stimulatory G-protein 1 (G alphas) and thyrotropin (TSH) receptor in its tumor tissue. Primary culture of cells from hyperfunctioning thyroid adenoma and its surrounding thyroid tissue revealed that cAMP production was constitutively activated while intracellular Ca2+ concentration was suppressed both at the basal level and in the response to TSH stimulation in the cells from tumor tissue compared with those from non-tumor tissue. Nucleotide sequence analysis demonstrated the somatic missense mutation at codon 201 (CGT(Arg)-CAT(His)) of G alphas gene in tumor tissue but not in its surrounding tissue. No mutation was observed in the transmembrane region of TSH receptor. These results suggest that cAMP regulatory cascade is constitutively activated while phospholipase C-Ca2+ signaling cascade is suppressed in hyperfunctioning thyroid adenoma with an activating mutation of G alphas gene in the present case.

Adenoma↗
PubMed1997

A new fine probe for electric cautery during endoscopic surgery.

The present paper introduces a new fine probe for electric cautery (1.65 mm in diameter, 22 cm long) that can be connected to a conventional cylindrical hand-controlled cautery holder, which is monopolar and widely used in general surgery. When cautery was required, a 14-gauge intravenous catheter was inserted at an appropriate site under the guidance of a videoscope. After removing the steel inner needle, the extra tube was used as the fine surgical port for the cautery probe. The position of insertion could be altered according to the operating field. Cautery was performed by conventional methods. There was no bleeding or air leakage at the site of puncture during or after surgery. The puncture wound was closed without any sutures. Based on these results, the new fine probe for cautery can reduce the number of surgical ports required for instruments during video-assisted surgery, thus improving the ease and safety of endoscopic surgery.

Electrocoagulation↗
PubMed1996

An adenosine derivative cooperates with TSH and Graves' IgG to induce Ca2+ mobilization in single human thyroid cells.

Digital video imaging indicated that about 80% of fura-2-loaded single human thyroid cells responded to TSH, resulting in an increase in intracellular Ca2+ concentration ([Ca2+]i). Most of the TSH-sensitive cells further responded to N6-(L-2-phenylisopropyl)-adenosine (PIA) showing a transient [Ca2+]i rise in a PIA dose-dependent manner. Addition of PIA prior to TSH administration had no effect or showed only a slight [Ca2+]i increase, but in about 80% of the cells, regardless of the response to PIA, the addition of TSH after PIA resulted in a higher transient [Ca2+]i response than that in the absence of PIA. Inactivation of Gi/G(o) by pertussis toxin (PTX) treatment markedly reduced the effect of PIA on TSH action to the level induced by PIA alone. Immunoglobulin fractions obtained from two Graves' patients with high TSAb (antibody activity measured by cAMP response) activity induced [Ca2+]i increase and cooperated with PIA. Under the same conditions, TSH-dependent cAMP accumulation was inhibited by PIA. These results suggest that adenosine Ai receptor is expressed in human thyroid cells in primary culture as well as in FRTL-5 rat thyroid cells, and that in the presence of adenosine. TSH or Graves' IgG signal tends to be directed to the Ca2+ pathway in the human thyroid.

Calcium↗
PubMed1992

Natural cytotoxic T cells responsible for anti-CD3-induced cytotoxicity in mice.

T cells obtained from normal mouse spleen cells showed significant cytotoxic activity against Fc receptor positive tumor cells in the presence of anti-CD3 monoclonal antibody (mAb). This activity was designated as natural cytotoxic T cell (NCT) activity and compared with natural killer (NK) activity. Considerable levels of NCT activity were detected in mouse strains with both high and low NK activity. NCT cells were distributed in both lower and higher density fractions of Percoll discontinuous density gradients, while NK cells were enriched in the lower density fraction of Percoll gradients. Moreover, NCT activity was resistant to in vivo anti-asialo GM1 treatment, in contrast to NK cells. These results indicate that NCT cells, which have different characteristics from NK cells, are present in normal, nonimmunized mouse spleen cells. Unexpectedly, CD4+ T cells sorted from normal mouse spleen T cells revealed significant NCT activity, as did CD8+ T cells. It was also demonstrated that NCT cells require the LFA-1 molecule to lyse tumor cells in the presence of anti-CD3 mAb.

Animals↗
PubMed1989

Cytochrome c-551 from the thermophilic bacterium PS3 grown under air-limited conditions.

A small-sized c-type cytochrome, designated cytochrome c-551, was prepared from membrane fraction of the thermophilic bacterium PS3 grown under air-limited conditions by extraction with cholate, precipitation with polyethylene glycol, and successive chromatographies with DEAE-cellulose and Sephacryl S-200 in the presence of a detergent. The purified sample contained approximately 1 mol of heme c per 10,000 g protein; it showed absorption bands at 551, 522 and 416 nm upon reduction, and a Soret peak at 409 nm upon oxidation. This cytochrome showed a single band of 10 kDa on polyacrylamide gel electrophoresis with sodium dodecyl sulfate. The isoelectric point of this cytochrome c-551 was pH 4.0. Cytochrome c-551 was suggested to play an important role in the respiratory chain with a terminal oxidase cytochrome o, which is produced under air-limited conditions, since cytochrome c-551 could mediate electron transfer between cytochrome bc1(b6f) complex and cytochrome o, showing quinol oxidase activity.

Bacterial Proteins↗
PubMed1987

Polypeptide-dependent protein kinase from bakers' yeast.

The purification and properties of a protein serine kinase (PK-P) extracted with Triton X-100 from membranes of bakers' yeast are described. The enzyme is virtually inactive unless either a histone or a heat-stable polypeptide from yeast membranes and Mg2+ are added. Other divalent cations substitute for Mg2+ poorly or not at all; most of them, including Mn2+, inhibit when added in the presence of 5 mM Mg2+. The enzyme is unstable but can be stabilized by addition of 0.1% Triton X-100 and 20% glycerol. The final preparation shows, on silver-stained electrophoresis gels, two major bands (Mr 41,000 and 35,000). According to gel filtration the molecular weight of the active protein is about 75,000. Of the two subunits, only the smaller one appears to be autophosphorylated. In addition to casein, the enzyme phosphorylates several proteins including the H+-ATPase (Mr 100,000) in the yeast plasma membrane. In order to demonstrate the phosphorylation of the ATPase (up to 0.9 equivalents), exposure of the latter to an acid phosphatase was required. Other phosphorylated proteins include mRNA cap-binding protein from mammalian erythrocytes and yeast, a glucocorticoid receptor protein, and a preparation of the guanine nucleotide-binding proteins Gi and Go from brain. A partial purification of a natural activator from yeast plasma membranes is described.

Chemical Phenomena↗
PubMed1984

High vectorial proton stoichiometry by cytochrome c oxidase from the thermophilic bacterium PS3 reconstituted in liposomes.

The stoichiometry of vectorial H+ ejection, coupled to ferrocytochrome c oxidation by a three-subunit bacterial cytochrome c oxidase (EC 1.9.3.1) from the thermophilic bacterium PS3, was measured. Three methods of measuring the H+/e- ratio were applied to proteoliposomes containing a relatively small amount of PS3 cytochrome oxidase, which showed a relatively low oxidation rate and a very low H+ leakage, as follows: (a) simultaneous measurements of H+ ejection and cytochrome c oxidation upon addition of a yeast ferrocytochrome c pulse, which enable us to calculate the H+/e- ratio as H+ ejected per cytochrome c oxidized; (b) computer simulations to find out the fit for the pH meter trace by changing the H+/e- ratio and the velocity constant of leakage; and (c) two successive measurements of initial rates of H+ movement in the absence and presence of carbonyl cyanide p-trifluoromethoxyphenylhydrazone. The H+/e- ratios obtained were 1.39, the 10-s value after ferrocytochrome c addition in (a), 1.35 in (b), and 1.33 in (c). This high H+/e- stoichiometry observed, exceeding 1 and as high as 1.4, is discussed with respect to the controversy of the H+/e- ratio at the cytochrome oxidase site.

Bacteria↗
PubMed1983

Proton pumping and oxidase activity of thermophilic cytochrome oxidase remain after its extensive proteolysis.

A proton-pumping heme aa3-type cytochrome oxidase purified from the thermophilic bacterium PS3 was treated with trypsin, thermolysin, chymotrypsin, subtilisin, or pronase. The cleavage of the oxidase subunits and the effects of their cleavage on the oxidase activity and proton-pumping in reconstituted vesicles were studied. Trypsin and thermolysin cleaved some of the oxidase subunits without affecting the proton-pumping, but subtilisin and pronase cleaved all the subunits resulting in partial decrease in both activities. Chymotrypsin had an intermediate effect. Subunit II of this enzyme contains heme c which is also cleaved by proteases.

Bacteria↗
PubMed1980

A cross-linking study of apo-low density lipoprotein.

Chemical cross-linking with dimethylsuberimidate was applied to the study of apo B interactions in human serum low density lipoprotein (LDL). Since apo B is known to have a mass of 500,000 to 600,000 daltons in non-ionic detergent solutions (i.e., a dimer of apo B based on the molecular weight of 260,000 for a single peptide of apo B), the possibility was investigated that the cross-linking reagent might be used to identify the interacting site of apo B in LDL. Although extensive cross-linking was observed in our experiment most of the reaction took place not between apo B's in one LDL (intramolecular) but between apo B's of different LDL's (intermolecular). Only a small fraction of cross-linked apo B dimer was formed intramolecularly. We interpret the results as indicating that the exposed or hydrophilic regions of LDL are scattered on the surface of LDL and that the protein-protein interaction site is not accessible to dimethylsuberimidate, probably being hidden under the surface layer of LDL.

Apolipoproteins↗