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Biomedical subjects

T Yagi

Publications and source records attributed to T Yagi.

At least 433 records · Page 24Linked to original sources
PubMed1993

[A case of primary pulmonary artery sarcoma].

A 39-year-old male was admitted with persistent cough, palpitations and dyspnea on exertion. Chest X-ray showed cardiomegaly, left pleural effusion and left hilar mass shadow. Echocardiogram revealed dilatation and hypertrophy of the right atrium and ventricle. Perfusion lung scintigram disclosed a complete defect of the left lung and a partial defect of the right upper lobe. CT scan showed an intravascular tumor mass in the bilateral main pulmonary arteries. Digital subtraction angiography of the pulmonary artery revealed complete obstruction of the left pulmonary artery and stenosis of the right pulmonary artery. MR image showed intravascular tumor infiltrating the mediastinum and surrounding tissue. Sarcoma was highly suspected, but a histopathological diagnosis could not be made. The patient died of heart failure two months after admission to our hospital. Postmortem examination showed that the pulmonary trunk and left main pulmonary artery were markedly dilated and completely occluded by the tumor. Tumor infiltrated into the left upper lobe and mediastinal lymph nodes. The tumor was histologically diagnosed as undifferentiated sarcoma.

Adult↗
PubMed1993

Isolation and characterization of the ND2 polypeptide of the bovine energy-transducing NADH-ubiquinone oxidoreductase (complex I).

The M(r) 30,000 polypeptide of the hydrophobic protein fraction of the energy-transducing NADH-ubiquinone oxidoreductase (complex I) of bovine heart mitochondria was identified as the ND2 gene product based on a comparison of amino acid analysis and partial N-terminal sequencing results with the known DNA sequence of ND2 (Anderson, S. et al. (1982) J. Mol. Biol. 156, 683-717). A simple purification procedure was devised for this ND2 gene product. The procedure, which is described, involves treatment of bovine complex I with a chloroform-methanol (2:1 [v/v]) solution. The antiserum raised against this purified bovine ND2 gene product cross-reacted with the approximately M(r) 39,000 polypeptide extracted from the Paracoccus denitrificans membranes with chloroform-methanol (2:1 [v/v]).

Amino Acid Sequence↗
PubMed1993

Activation of c-mos oncogene by integration of an endogenous long terminal repeat element during transfection of genomic DNA from mouse skin tumor cells.

An activated c-mos oncogene was identified in a transformed clone of golden hamster embryo cells transfected with DNA extracted from cells cultured from a UV-induced mouse skin tumor. Southern blot hybridization with a v-mos oncogene probe showed that the mos oncogene was amplified in the primary and secondary transformed cells but not in the original tumor cells. Expression of the mos oncogene was very high in the primary and secondary transformants, but mos mRNA was undetectable in the original tumor cells. A genomic DNA fragment containing the activated mos oncogene was cloned and sequenced. The upstream mouse sequence of the mos oncogene, which functions as the transcription terminator, was lost and replaced by a mouse endogenous long terminal repeat (LTR) element that provides the promoter sequence, resulting in high expression of the gene. The rearrangement apparently occurred during transfection, since the polymerase chain reaction (PCR) product encompassing the junction region was present in the primary and secondary transformants but not in the original tumor cells. The LTR element is likely to have been amplified during the skin tumor development caused by UV irradiation. Southern blot hybridization showed that the copy number of LTR in the tumor cells was significantly higher than that in normal skin cells. The amplification of the LTR in the cells may have increased the chance of recombination between the LTR and c-mos gene during the DNA transfection.

Animals↗
PubMed1993

[Clinical features and prognosis of Churg-Strauss syndrome].

We studied the clinical features and prognosis of 11 patients with Churg-Strauss syndrome (CSS). Subjects included 1 man and 10 women with a mean age of 56.3 years. All subjects had a history of bronchial asthma prior to the onset of CSS. It was noted that the age of onset of bronchial asthma was high, and most of the patients had suffered from frequent and severe asthmatic attacks during the periods preceding the vasculitis. Skin tests and IgE RAST revealed that less than half of the subjects were atopic. Therefore it is considered that asthmatics with late onset and severe symptoms have a high risk for CSS, and poor control of asthmatic symptoms may contribute to the onset of the vasculitis. Eleven of 12 cases including 1 patient with a relapse were treated with PSL alone (9 cases) or PSL plus cyclophosphamide (2 cases). Three patients died of heart failure or central nerve involvement. Vasculitis was ameliorated in the other cases (75%). Seven patients received maintenance therapy with low-dose of PSL (5 cases) or cyclophosphamide (2 case). None suffered from relapse of vasculitis during maintenance therapy. Discontinuation of therapy in five cases resulted in a relapse in only one case 62 months after the cessation of low-dose PSL. Although maintenance therapy appears to be useful in some CSS patients, the significance and indications for maintenance therapy should be further clarified.

Adult↗
PubMed1993

[Investigation of self-discharged patients of pulmonary tuberculosis].

This study investigates 27 cases in which the patients left hospital care without permission for personal reasons. These patients were classified as "self-discharged patients". Each of the patients had been diagnosed as having pulmonary tuberculosis, and were receiving treatment at the National Chiba Higashi Hospital during the period from January 1988 to July 1991. Disease was in an advanced stage in each of the patients when admitted: all sputum examinations were positive and chest roentgenograms revealed cavities in 26 patients. In addition to pulmonary tuberculosis, the patients were also diagnosed has having a variety of other medical complications such as diabetes mellitus, gastric ulcers and liver disease. Many of them were unemployed or were day labors. Reasons attributed to patients self-discharge from the hospital included repetition of alcohol drinking and unauthorized outings. At the time patients chose to leave hospitalization 11 cases checked positive for sputum examinations, and 16 cases never returned to complete therapy. Many of them were rated as high risk patients for pulmonary tuberculosis because they had no immediate family, did not own a residence or have regular employment thus economic and psychological conditions were very low. There is a high possibility that these individuals will suffer pulmonary tuberculosis relapse and become infectious bacteria carriers. It is important that such patients be hospitalized long enough to receive adequate treatment to prevent then from becoming infectious carriers and spreading disease.

Adolescent↗
PubMed1992

A novel tyrosine kinase, hyk, expressed in murine embryonic stem cells.

To identify tyrosine kinases which play roles in mammalian early development, the 3' rapid amplification of cDNA ends (RACE) was performed on mouse embryonic stem (ES) cells. Among eight tyrosine kinases thus identified, we report here a novel tyrosine kinase, hyk (adhesion structures linked tyrosine kinase). The sequences of the 4.7 kb cDNA indicated the presence of RGD motif and three epidermal growth factor-like domains put between two immunoglobulin-like domains and three fibronectin type III domains in its extracellular region. It is strongly expressed in ES cells and later stages of embryos, but at low levels in midgestation embryos. It is also expressed at a low level in neural precursor cells from 10-day embryos, but at high levels in embryonic day 15 and neonatal brains. In adult tissues it is expressed ubiquitously.

Amino Acid Sequence↗
PubMed1992

Gene cluster of the energy-transducing NADH-quinone oxidoreductase of Paracoccus denitrificans: characterization of four structural gene products.

In previous reports from our laboratory, the three structural genes (NQO1, NQO2, and NQO3) of the energy-transducing NADH-quinone oxidoreductase of Paracoccus denitrificans were characterized [Xu, X., Matsuno-Yagi, A., & Yagi, T. (1991) Biochemistry 30, 6422-6428; (1991) Biochemistry 30, 8678-8684; (1992) Arch. Biochem. Biophys. 296, 40-48]. In this report, the four structural genes NQO4, NQO5, NQO6, and NQO7 of the same Paracoccus denitrificans oxidoreductase were cloned and sequenced. On the basis of sequence homology and immunological cross-reactivity, these genes encode counterparts of the 49-, 30-, and 20-kDa polypeptides and the mitochondrial DNA ND3 polypeptides of bovine mitochondrial complex I. These seven structural genes were found to be located in the same gene cluster. The order of the seven structural genes of the Paracoccus NADH-quinone oxidoreductase in the gene cluster is NQO7, NQO6, NQO5, NQO4, NQO2, NQO1, and NQO3. Upstream of the NQO7 gene, an open reading frame encoding a predicted polypeptide homologous to the UV repair enzyme A of Escherichia coli and Micrococcus lysodeikticus was detected. The 5'-terminus of the gene cluster carrying the Paracoccus NADH-quinone oxidoreductase was studied, and the possible promoter region is discussed. The NQO4 and NQO5 genes appear to code for the M(r) 48,000 and 21,000 polypeptides of the isolated Paracoccus NADH dehydrogenase complex [Yagi, T. (1986) Arch. Biochem. Biophys. 250, 302-311] on the basis of amino acid analyses and N-terminal protein sequence analyses. The antisera to the bovine complex I 49- and 30-kDa polypeptides cross-reacted with the Paracoccus 48- and 21-kDa subunits, respectively.

Amino Acid Sequence↗
PubMed1992

EPR and redox properties of Desulfovibrio vulgaris Miyazaki hydrogenase: comparison with the Ni-Fe enzyme from Desulfovibrio gigas.

We have carried out a detailed redox titration monitored by EPR on the hydrogenase from Desulfovibrio vulgaris Miyazaki. Typical 3Fe and nickel signals have been observed, which are very similar to those given by Desulfovibrio gigas hydrogenase in all the characteristic redox states of the enzyme. This confirms that D. vulgaris Miyazaki hydrogenase is a Ni-Fe enzyme closely related to that from D. gigas, as was recently proposed on the basis of sequence comparisons (Deckers, H.M., Wilson, F.R. and Voordouw, G. (1990) J. Gen. Microb. 136, 2021-2028).

Desulfovibrio vulgaris↗
PubMed1992

Salt tolerance and glycerol accumulation of a respiration-deficient mutant isolated from the petite-negative, salt-tolerant yeast Zygosaccharomyces rouxii.

A respiration-deficient (RD) mutant was isolated from the petite-negative, salt-tolerant yeast Zygosaccharomyces rouxii. One strain among sixteen glycerol-non-utilizing mutants exhibited vigorous liberation of CO2 but no uptake of O2. Furthermore, this strain lacked cytochrome aa3 and had a reduced level of cytochrome b. The few mitochondria found in cells of this strain contained few or no cristae. Salt tolerance and intracellular accumulation of glycerol by the RD strain were almost equal to that of the wild-type strain in media containing NaCl up to 2.5 M. In media with more than 3 M NaCl, the growth of the RD mutant was retarded and the intracellular accumulation of glycerol was depressed in spite of ample production.

Adaptation, Biological↗
PubMed1992

Three-component analysis of caloric nystagmus in humans.

Three-component analysis of caloric nystagmus, focusing on the horizontal, vertical, and torsional, using a computerized eye movement analysis system, was carried out in 10 normal human subjects. The caloric response was induced by cold stimulation to the right ear of the subjects in the supine and prone positions. In the supine position, the three components of nystagmus were toward the left (10 subjects), upward (eight subjects) or downward (two subjects), and clockwise (10 subjects). In the prone position, on the other hand, the three components were directed toward the right (10 subjects), downward (five subjects), upward (three subjects), and counterclockwise (10 subjects); there was no vertical direction in two subjects. These findings indicate that caloric stimulation activates the three semicircular canals simultaneously. Also the changes in the nystagmus direction in the supine and prone positions could be explained, at least partially, by the nonconvective component of caloric stimulation.

Adult↗
PubMed1992

A newly developed hydroxyl radical scavenger, EPC-K1 can improve the survival of swine warm ischemia-damaged transplanted liver grafts.

Using a swine orthotopic liver transplantation (SOLTx) model, we assessed the effect of a new hydroxyl radical scavenger EPC-K1 on warm ischemic damage of the liver graft and recipient survival. Animals were divided into 5 groups. The first group (control group 1) consisted of 5 pigs which were not operated on but served as controls for the indocianine green disappearance rate (K-ICG) determinations. In the second group (control group 2), 10 livers were transplanted without warm ischemia (WI) and the K-ICG values were measured. The third group (control group 3) was the main control group for the study groups and consisted of 5 liver transplants with 30 min of WI without any special treatment. The fourth and fifth groups served as study groups 1 and 2. Five transplants were carried out in each group, as in control group 3. In study group 1 recipients were treated with an additional 5 mg/kg i.v. EPC-K1 and in study group 2 with 20 mg/kg i.v. EPC-K1. Significant improvement in glutamic oxaloacetic transaminase (GOT) and lactate dehydrogenase (LDH) levels, K-ICG values and histological findings were observed in the EPC-K1 treated groups. The intravenous administration of this agent had a strong protective effect on warm ischemic damage after 30 min of WI and could significantly prolong the graft and recipient survival.

Animals↗
PubMed1992

Structural features of the 66-kDa subunit of the energy-transducing NADH-ubiquinone oxidoreductase (NDH-1) of Paracoccus denitrificans.

The structural gene of the Paracoccus denitrificans NADH-ubiquinone oxidoreductase encoding a homologue of the 75-kDa subunit of bovine complex I (NQO3) has been located and sequenced. It is located approximately 1 kbp downstream of the gene coding for the NADH-binding subunit (NQO1) [Xu, X., Matsuno-Yagi, A., and Yagi, T. (1991) Biochemistry 30, 6422-6428] and is composed of 2019 base pairs and codes for 673 amino acid residues with a calculated molecular weight of 73,159. The M(r) 66,000 polypeptide of the isolated Paracoccus NADH dehydrogenase complex is assigned the NQO3 designation on the basis of N-terminal protein sequence analysis, amino acid analysis, and immuno-cross-reactivity. The encoded protein contains a putative tetranuclear iron-sulfur cluster (probably cluster N4) and possibly a binuclear iron-sulfur cluster. An unidentified reading frame (URF3) which is composed of 396 base pairs and possibly codes for 132 amino acid residues was found between the NQO1 and NQO3 genes. When partial DNA sequencing of the regions downstream of the NQO3 gene was performed, sequences homologous to the mitochondrial ND-1, ND-5, and ND-2 gene products of bovine complex I were found, suggesting that the gene cluster carrying the Paracoccus NADH dehydrogenase complex contains not only structural genes encoding water-soluble subunits but also structural genes encoding hydrophobic subunits.

Amino Acid Sequence↗
PubMed1992

UV-induced base substitution mutations in a shuttle vector plasmid propagated in group C xeroderma pigmentosum cells.

To assess the contribution to mutagenesis of human DNA repair defects, the UV-irradiated shuttle vector plasmid pZ189 was propagated in fibroblasts derived from a xeroderma pigmentosum (XP) patient in DNA repair complementation group C. In comparison to results with DNA repair-proficient human cells (WI-38 VA13), UV-irradiated pZ189 propagated in the XP-C (XP4PA(SV)) cells showed fewer surviving plasmids and a higher frequency of mutated plasmids. Base sequence analysis of 67 mutated plasmids recovered from the XP-C cells revealed similar classes of point mutations and mutation spectrum, and a higher frequency of G:C to A:T transitions along with a lower frequency of transversions among plasmids with single or tandem mutations compared to plasmids recovered from the normal line. Most single-base substitution mutations (83%) occurred at G:C base pairs in which the 5'-adjacent base of the cytosine was thymine or cytosine. These results indicate that the DNA repair defects in XP-C, in comparison to data previously reported for XP-A, XP-D and XP-F, result in different UV survival and mutation frequency but in similar types of base substitution mutations.

Base Sequence↗
PubMed1992

Does the type of anomalous arrangement of pancreaticobiliary ducts influence the surgery and prognosis of choledochal cyst?

A new classification of the anomalous arrangement of pancreaticobiliary ducts (APBD) has been proposed following amendments and modificiations of the previous one. Fifty-one cases of choledochal cyst complicated with APBD were extensively examined and analyzed for clear visualization of the APBD system to make a standard classification. APBD were classified broadly into three types: type I, type II, and type III with their subtypes. Type I of APBD was seen in 18 (35.3%), type II in 11 (21.6%) and type III in 22 (43.1%) cases, respectively. A radical operation, including complete excision of the dilated biliary duct followed by reconstruction of the biliary tract was the surgical treatment of choice, because the reflux of the pancreatic juice into the biliary tract is prevented. However, a dilated common channel or accessory pancreatic duct, according to the new Komi type Ib, IIb, and IIIc3 of APBD, could be the cause of relapsing pancreatitis leading to chronic pancreatitis, due to the formation of a protein plug or pancreatic calculus in the dilated duct, even after this radical operation. In two complicated cases of type IIIc3 of APBD in choledochal cyst, we performed a pylorus-preserving pancreatoduodenectomy as one of the operative methods of choice. Long-term follow-up, more than decades, is essential to evaluate the results of surgical procedure for choledochal cyst, especially in those complicated cases with type Ib, IIb, and IIIc3 of APBD according to the new Komi's classification.

Adolescent↗
PubMed1992

Mice develop normally without tenascin.

Tenascin, an extracellular matrix protein, is expressed in an unusually restricted pattern during embryogenesis and has been implicated in a variety of morphogenetic phenomena. To directly assess the function of tenascin in vivo, we generated mutant mice in which the tenascin gene was nully disrupted by replacing it with the lacZ gene. In mutant mice, lacZ was expressed in place of tenascin, and no tenascin product was detected. Homozygous mutant mice were, however, obtained in accordance with Mendelian laws, and both females and males produced offspring normally. No anatomical or histological abnormalities were detected in any tissues, and no major changes were observed in distribution of fibronectin, laminin, collagen, and proteoglycan. The existence of these mutant mice, lacking tenascin yet phenotypically normal, casts doubt on the theory that tenascin plays and essential role in normal development.

Animals↗