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Biomedical subjects

K Asada

Publications and source records attributed to K Asada.

At least 91 records · Page 5Linked to original sources
PubMed1994

[Esophageal perforation after replacement of descending thoracic aorta for rupture mycotic aneurysm].

Primary mycotic aneurysm of the thoracic aorta has rarely been reported. The patient was a 61-year-old male who had a ruptured mycotic aneurysm of the descending thoracic aorta without any evidence of infectious disorders in his history. The patient developed esophageal perforation after graft replacement of the descending thoracic aorta. After continuous irrigation of the left pleural cavity and the mediastinum for one month, the thoracic esophagus was resected and reconstructed. However, the patient died of DIC following uncontrolled sepsis on the 98th postoperative day. Pathogenesis of the esophageal perforation and operative procedures that might have been effective in saving the patient were discussed.

Aneurysm, Infected↗
PubMed1994

[Reoperation for mitral valve disease].

From 1978 to March 1994, 95 patients underwent repeated open heart surgery for mitral valve diseases. There were 48 men and 47 women. The mean age was 50 and the mean interval between initial and second operation was 8 years. The initial operations were OMC in 39, MAP in 13, OMC+MAP in 11, MVR in 30 and AVR in 2 patients. The hospital death occurred in 31 cases (32.6%). In recent cases, however the hospital death were reduced to 4 (14.8%). This was attributed to the change in myocardial protection from previous intermittent antegrade crystalloid to recent continuous combined antegrade and retrograde cardioplegia.

Adolescent↗
PubMed1994

cDNA cloning of monodehydroascorbate radical reductase from cucumber: a high degree of homology in terms of amino acid sequence between this enzyme and bacterial flavoenzymes.

The FAD-enzyme monodehydroascorbate (MDA) reductase catalyzes the regeneration of ascorbate from the MDA radical using NAD(P)H as the electron donor [Hossain and Asada (1985) J. Biol. Chem. 260: 12920]. We cloned a cDNA of MDA reductase from cucumber seedlings and deduced its entire sequence of amino acid residues. The cDNA library from cucumber seedlings in the expression vector was screened with an antiserum against cucumber MDA reductase. Inserts from three immunoscreened clones hybridized with two oligonucleotide probes designed on the basis of the sequences of two peptide fragments from the cucumber enzyme. The nucleotide sequences of these three clones were determined and the longest one contained an open reading frame of 1,302 bp in length. The molecular mass of the translation product predicted from the open reading frame was 47 kDa, the same as that determined for the purified enzyme. The amino acid sequences determined from fragments of lysyl endopeptidase-digested MDA reductase could be aligned with that deduced from the open reading frame, although substitution of several residues was apparent. Thus, the open reading frame encoded an isozyme of MDA reductase of cucumber different from the purified enzyme. MDA reductase has the FAD- and NAD(P)H-binding domains of flavoproteins but shares only limited homology in terms of amino acid sequence with flavoenzymes from eukaryotes.

Amino Acid Sequence↗
PubMed1994

[Surgical treatment of infective endocarditis].

Since 1976, 37 patients have undergone valve replacement for infective endocarditis at our institute. Twenty patients required surgery during the active stage and 17 in the inactive stage. The former group consisted of 17 native and three prosthetic valve endocarditis, and all patients in the latter group had native valve endocarditis. Eighteen patients had AVRs, 15 had MVRs and four had DVRs. Congestive heart failure was the indication for surgery in 80% of the active and 100% of the inactive group. There were nine early deaths (45%) and one late death in the active group, and one early (6%) and one late death in the inactive group. Operative mortality in the active group, however, has recently been reduced to 30% for the 10 patients operated upon in the past two years. Two patients with active endocarditis were complicated by rupture of cerebral mycotic aneurysms postoperatively and resulted in one early and one late death, respectively. It is suggested that timely surgical intervention according to the hemodynamic state of the patients is essential in reducing early mortality in infective endocarditis. Attention should be paid to cerebral mycotic aneurysm as one of the problems affecting on postoperative mortality and morbidity.

Adult↗
PubMed1993

Molecular cloning and cDNA sequencing of endoxyloglucan transferase, a novel class of glycosyltransferase that mediates molecular grafting between matrix polysaccharides in plant cell walls.

Endoxyloglucan transferase is a novel class of glycosyltransferase recently purified from Vigna angularis (Nishitani, K,, and Tominaga, R. (1992) J. Biol. Chem. 267, 21058-21064). This enzyme is the first transferase identified that catalyzes molecular grafting between polysaccharide cross-links in the cell wall matrix and participates in reconstruction of the network structure in the cell wall. Based on the NH2-terminal amino acid sequence information of the purified transferase, we have here cloned and sequenced cDNAs derived from five different plant species, V. angularis, Triticum aestivum, Arabidopsis thaliana, Lycopersicon esculentum, and Glycine max. In the five plant species, the amino acid sequence of the mature proteins is conserved in the range of 71-90% throughout their length. The consensus sequence for N-linked glycosylation, and four cysteine residues are all conserved in the five species. Thus, the endoxyloglucan transferase protein is ubiquitous among higher plants. The highly conserved DNA sequence will serve as a promising tool for exploring the molecular process by which cell wall construction, and hence cell growth, is regulated.

Amino Acid Sequence↗
PubMed1993

Alpha-amylase from the hyperthermophilic archaebacterium Pyrococcus furiosus. Cloning and sequencing of the gene and expression in Escherichia coli.

A gene encoding a highly thermostable alpha-amylase from the hyperthermophilic archaebacterium Pyrococcus furiosus was cloned and expressed in Escherichia coli. The nucleotide sequence of the gene predicts a 649-amino acid protein with a calculated molecular mass of 76.3 kDa, which corresponds well with the value obtained from purified enzyme using denaturing polyacrylamide gel electrophoresis. The NH2 terminus of the deduced amino acid sequence corresponds precisely to that obtained from the purified enzyme, excluding the NH2-terminal methionine. The amylase expressed in E. coli exhibits temperature-dependent activation characteristic of of the original enzyme from P. furiosus, but has a higher apparent molecular weight which is attributed to the improper formation of the native quaternary structure. No homology was found with previously characterized promotor or termination sequences. The deduced amino acid sequence displayed strong homology to the alpha-amylase A of Dictyoglomus thermophilum, an obligately anaerobic, extremely thermophilic bacterium. Evolutionary implications of this homology are discussed.

Amino Acid Sequence↗
PubMed1993

Organization and nucleotide sequence of the DNA polymerase gene from the archaeon Pyrococcus furiosus.

We cloned the gene encoding the thermostable DNA polymerase from the archaeon Pyrococcus furiosus. The DNA fragment of 2785 base pair (bp) containing the structural gene for DNA polymerase was sequenced. DNA polymerase (Pfu polymerase), as deduced from the DNA sequence, consisted of 775 amino acids, had a molecular weight of 90, 109, and was structurally homologous to the alpha-like DNA polymerases (family B) represented by human DNA polymerase alpha and Escherichia coli DNA polymerase II. An unrooted phylogenetic tree of the alpha-like DNA polymerases based on the amino acid sequence alignment was constructed. Pfu polymerase, with two other archaeon polymerases, constitutes a group with some animal viruses. The transcription initiation sites of the pol gene were identified by analysis of in vivo transcripts of both from P. furiosus and E. coli, and the promoters were assigned upstream of the pol coding region. A typical promoter sequence for the archaeon was found at a reasonable distance from the transcription initiation site in P. furiosus.

Amino Acid Sequence↗
PubMed1993

Cloning of the DNA polymerase gene of Bacillus caldotenax and characterization of the gene product.

The pol gene of the thermophilic eubacterium Bacillus caldotenax was cloned in a plasmid and expressed in Escherichia coli. The PCR method was used to clone the gene with no previous knowledge of the gene or protein sequence. The 3,329-bp DNA fragment containing the structural gene for DNA polymerase was sequenced. DNA polymerase, as deduced from the DNA sequence, consisted of 877 amino acids, had a molecular weight of 99,452, and was structurally homologous to the DNA polymerases of the Pol I family (family A), which includes E. coli DNA polymerase I and T7 DNA polymerase. B. caldotenax DNA polymerase (Bca polymerase) purified from the recombinant E. coli strain was characterized. Like E. coli Pol I, Bca polymerase had 5'-->3' exonuclease activity. The degraded product with the molecular weight of 65,000 was also purified and found to have polymerase activity. To overproduce this Klenow-type fragment of Bca polymerase, a recombinant expression plasmid pUI205 with a deletion in the 5'-region of the pol structural gene was constructed. The DNA polymerase produced by pUI205 is more suitable for use in the dideoxy sequencing method than the other DNA polymerases that have been used for sequencing.

Amino Acid Sequence↗
PubMed1993

[Cell-associated interleukin 1 production of alveolar macrophages from bleomycin-induced pulmonary fibrosis in rats].

In order to clarify the mechanisms of pulmonary fibrosis, we produced bleomycin (BLM)-induced pulmonary fibrosis in rats and examined the ability of alveolar macrophages (AM) to produce interleukin-1 (IL-1). BLM (0.9 mg) was administered once via the trachea to male Wistar rats weighing about 200 g. Bronchoalveolar lavage was performed at 1, 3, 6, 9 and 12 days after administration. AM were incubated for 24 hours, then extracellular IL-1 in the supernatants and cell-associated IL-1 of AM were measured by proliferation assay of mouse thymocytes. Cell-associated IL-1 activity was measured after fixation by paraformaldehyde (PFA). Extracellular IL-1 was detected in the culture media of AM at only day 1 after administration. On the other hand, cell-associated IL-1 was detected in AM fixed by PFA on days 1, 3, 6 and 9 after administration. AM from BLM-induced pulmonary fibrosis in rats were fixed by PFA and then were treated with anti-IL-1 alpha antibody or anti-IL-1 beta antibody. Cell-associated IL-1 activity was neutralized by treatment with anti-IL-1 alpha antibody and was not neutralized by treatment with anti-IL-1 beta antibody. Following this, the effect of cell-associated IL-1 on pulmonary fibroblasts was examined. This was estimated by the proliferation of pulmonary fibroblasts using incorporation of 3H-thymidine. When pulmonary fibroblasts were incubated with AM fixed by PFA from BLM-induced pulmonary fibrosis in rats, proliferation of pulmonary fibroblasts was inhibited.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Expression of the differentiated phenotype of chondrocytes in newly synthesized acetabulum.

Human cartilaginous cells produce two types of proteoglycan monomers (PGI and PGII) distinguishable by their molecular size in density gradient centrifugation under dissociative conditions. In order to determine whether connective tissues on the sliding surface of the acetabulum on an endoprosthesis are able to differentiate into cartilaginous tissue, we made histological and biochemical analysis of the incorporation of 35S and the distribution of the molecular size of proteoglycans produced. Histologically, dense collagen fibers were observed both on weight-bearing and non-weight-bearing surfaces, but there was little evidence of cartilaginous metaplasia. Biochemical analysis, however, demonstrated that incorporation of 35S in newly synthesized glycosaminoglycan (GAG) was higher than that in non-cartilaginous tissues, suggesting that cartilaginous differentiation of mesenchymal tissues had occurred.

Acetabulum↗
PubMed1993

MR imaging of anomalous lobes of the liver.

Four patients with anomalous lobes of the liver were observed at MR imaging. In one patient the anterior segment of the right hepatic lobe was absent and in 3 patients the left hepatic lobe was anomalous. The hepatic vasculature supporting the information of the anomalous hepatic lobes was well observed in all patients.

Congenital Abnormalities↗
PubMed1993

[Risk factors and therapeutic methods for sternal wound infection following cardiac surgery].

In a study of 1040 patients undergoing cardiac surgery at The Osaka Medical College Hospital from 1984 through 1991, we analyzed the correlation between a variety of preoperative and operative parameters and the risk of postoperative sternal wound infection, as well as the efficacy of various therapeutic method for this condition. Sternal infection or mediastinitis developed after cardiac surgery in 31 patients (3.0%). As the risk factors for wound infections, age, diabetes mellitus, reexploration, duration of cardiopulmonary bypass and use of bilateral internal thoracic artery grafting were listed. Application of pectoral muscle flaps significantly led to shorten a duration between diagnosis of infection and hospital discharge, and increased survival rate, than the other treating methods such as debridement or irrigation. We conclude that bilateral internal thoracic artery grafts should not be used in the cases with diabetes, and closure with pectoral muscle flaps is effective for sternal infection and mediastinitis.

Coronary Artery Bypass↗
PubMed1993

[Neutrophil chemotactic factor in supernatant from pulmonary fibroblasts stimulated with cytokines].

Fibroblasts are important for maintenance of the structural frame network for most tissues, and they also play an important role in the inflammatory process via production of various mediators. In this study, we demonstrated that pulmonary fibroblasts may participate in pulmonary inflammation by production of neutrophil chemotactic factor (NCF). Pulmonary fibroblasts were stimulated with various cytokines (IGF-1, PDGF, IL-1 alpha, IL-1 beta, IL-2, IL-6, TNF, IFNr). Fibroblasts stimulated with either TNF, IL-1 alpha or IL-beta but not IGF, PDGF, IL-2 or IL-6 demonstrated a kinetic and dose-dependent increase in NCF activity. The NCF activity of crude supernatant was heat-stable and was not changed by anti-C5 antibody treatment or ether extraction. Characterization of the NCF activity by gel-filtration using high pressure liquid chromatography showed two active fractions, one with MW greater than 100 kD and the other with MW less than 10 kD. NCF activity in the small molecular weight fraction was demonstrated by inhibition of chemotaxis by addition of anti-IL-8 antibody. These data suggest that cytokine-treated fibroblast-derived NCF may be important in the pathogenesis and expression of a variety of pulmonary disease processes associated with neutrophil accumulation and activation.

Cytokines↗
PubMed1992

Genomic structure of the human caldesmon gene.

The high molecular weight caldesmon (h-CaD) is predominantly expressed in smooth muscles, whereas the low molecular weight caldesmon (l-CaD) is widely distributed in nonmuscle tissues and cells. The changes in CaD isoform expression are closely correlated with the phenotypic modulation of smooth muscle cells. During a search for isoform diversity of human CaDs, l-CaD cDNAs were cloned from HeLa S3 cells. HeLa l-CaD I is composed of 558 amino acids, whereas 26 amino acids (residues 202-227 for HeLa l-CaD I) are deleted in HeLa l-CaD II. The short amino-terminal sequence of HeLa l-CaDs is different from that of fibroblast (WI-38) l-CaD II and human aorta h-CaD. We have also identified WI-38 l-CaD I, which contains a 26-amino acid insertion relative to WI-38 l-CaD II. To reveal the molecular events of the expressional regulation of the CaD isoforms, the genomic structure of the human CaD gene was determined. The human CaD gene is composed of 14 exons and was mapped to a single locus, 7q33-q34. The 26-amino acid insertion is encoded in exon 4 and is specifically spliced in the mRNAs for both h-CaD and l-CaDs I. Exon 3 is the exon that encodes the central repeating domain specific to h-CaD (residues 208-436) together with the common domain in all CaD (residues 73-207 for h-CaD and WI-38 l-CaDs, and residues 68-201 for HeLa l-CaDs). The regulation of h- and l-CaD expression is thought to depend on selection of the two 5' splice sites within exon 3. Thus, the change in expression between l-CaD and h-CaD might be caused by this splicing pathway.

Alternative Splicing↗
PubMed1992

Molecular cloning and nucleotide sequence determination of the regulator region of mecA gene in methicillin-resistant Staphylococcus aureus (MRSA).

Molecular cloning and nucleotide sequence analysis were performed for the identification of the regulator genes of methicillin resistance in the genome of a MRSA strain N315. Two open reading frames (orfs) were identified in the 5'-flanking region of the mecA gene. Predicted amino acid sequences of these orfs showed extensive homology to the co-inducer and the repressor protein of the penicillinase (PCase) production in Staphylococcus aureus as well as in Bacillus licheniformis. These orfs are considered to encode putative co-inducer and repressor proteins specific for the regulation of methicillin resistance in MRSA.

Amino Acid Sequence↗
PubMed1992

'boxA'-like sequence between the 16 S/23 S spacer in rRNA operon of mycoplasmas.

We have found that a boxA-like sequence is conserved in the 16 S and 23 S rRNA intergenic spacer regions of mycoplasmas, and that it always locates on loop regions of the hypothetical secondary stem-loop structures. A nucleotide sequence similar to the '-10' box of prokaryotic promoters was identified at upstream sites of the boxA-like sequence in the 16 S/23 S spacer regions. These structures may represent an internal promoter between the 16 S and 23 S rRNA genes in mycoplasmas.

Base Sequence↗
PubMed1992

Nucleotide sequence of the arginine deiminase gene of Mycoplasma hominis.

The arginine deiminase gene of Mycoplasma hominis was amplified by the polymerase chain reaction, and its entire nucleotide sequence was determined. This gene consists of 1227 base pairs encoding 409 amino acids, and has 35.2% guanine plus cytosine content. Nucleotide sequence homologies of the arginine deiminase gene between M. hominis and M. arginini, and between M. hominis and M. orale were 82.1 and 80.8%, respectively, suggesting that this gene is highly conserved among arginine-utilizing Mycoplasma species.

Amino Acid Sequence↗