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Biomedical subjects

Y Yoshida

Publications and source records attributed to Y Yoshida.

At least 829 records · Page 46Linked to original sources
PubMed1994

[Allograft (homograft) valve surgery: current status in Japan].

The advance of cryopreservation techniques has dramatically increased the durability of human allograft valves, resulting in the wide-spread use of allograft valves in many western countries except Japan. The superiority of the allograft valve to other prosthetic valves has become apparent in some specific situations such as active endocarditis, small aortic root and hemorrhagic conditions. In this manuscript, we described the setting-up of the cryopreservation laboratory, quality control and the clinical use of allograft valves in our institute. The authors believe that surgeons should have an option of utilizing allograft valves in selected patients in Japan.

Adult↗
PubMed1994

[Coronary artery bypass surgery-redo operation particularly in patients with a functioning ITA graft or with a patent atheromatous vein graft].

An experience with redo-CABG in 20 patients is described. The incidence of reoperation in patients undergoing primary CABG in our hospital was 1.4%, relatively low even in Japanese population. The low incidence of redo-CABG in our hospital depends on the relatively short period of follow-up of 14 years, the prevalence of interventional cardiology and the early routine use of ITA grafts. The main cause of reoperation was the failure of a SVG to the LAD in 70 to 80% of the cases. The most important and difficult decision-making in redo-CABG is the selection of surgical approaches and cardioprotective methods in patients with a patent functioning ITA graft, and the management of an atherosclerotic patent SVG. Surgical strategies in these situations are discussed.

Adult↗
PubMed1993

Effects of metal chelating agents on the oxidation of lipids induced by copper and iron.

The non-enzymatic oxidations of soybean phosphatidylcholine liposomes, methyl linoleate micelles and low-density lipoprotein in aqueous dispersions induced by copper and iron have been studied aiming specifically at elucidating the action of the metal chelating agents such as ethylenediaminetetraacetic acid disodium salt (EDTA), nitrilotriacetic acid (NTA), adenosine-5'-diphosphate disodium salt (ADP), desferrioxamine (DFO), penicillamine (PCM), and triethylene tetramine (TTM). The effects of chelators on chemiluminescence emitted from its probe luminol in the decomposition of tert-butyl hydroperoxide by metal ion were also studied. The effects of chelators on the oxidations depended both on the metal ion and the substrate. Namely, in the oxidations of both liposomes and micelles, EDTA and NTA suppressed the copper-induced oxidations, whereas they enhanced the oxidations induced by iron. ADP had little effect, while PCM and TTM had accelerating effect for both metal ions. On the other hand, in the oxidation of LDL, none of these chelators enhanced the oxidation. Especially, TTM and PCM suppressed the copper-induced oxidation of LDL, suggesting that the chelating agents blocked the access of the metal ion to the hydroperoxide within LDL. The effects of chelators on chemiluminescence emission were similar to those on the oxidations of liposomes and micelles. The cyclic voltammograms of metal complexes were also measured. The multiple effects of chelators on the rate of non-enzymatic, metal-catalyzed oxidations of lipids were interpreted by their influence on redox-potential and accessibility to hydroperoxide of the metal-chelator complex.

Chelating Agents↗
PubMed1993

Cloning of a cDNA which encodes a novel ubiquitin-like protein.

The cloning of a mouse cDNA, Nedd-8, which encodes a small novel protein of 81 amino acid residues with a relative molecular mass of 9 kDa, is described. The putative Nedd-8 product is approximately 60% identical to ubiquitin protein. The 0.6 kb mRNA for Nedd-8 gene can be detected in various mouse tissues and cell lines derived from various sources. Nedd-8 probe hybridizes to genomic DNA from various vertebrate species as well as yeast, indicating high degree of interspecies conservation. These data suggest that like ubiquitin, the product of this gene may play some essential role in eukaryotic cellular metabolism.

Amino Acid Sequence↗
PubMed1993

Pro-major basic protein has three types of sugar chains at the pro-portion.

The amino-acid sequence of purified recombinant pro-major basic protein from Chinese hamster kidney cells was determined to verify the primary structure and glycosylation sites. Reduced and S-carboxamidemethylated protein was first digested with Achromobacter proteinase I. Each peptide was characterized by amino-acid analysis and amino-acid sequence analysis. We could identify all the peptides which were expected from the pro-major basic protein cDNA sequence. Sequence analysis and deglycosylation study revealed that Ser-8, Thr-9, Ser-46 and Asn-70 were glycosylated. The results indicated that proMBP has three types of sugar chains, O-glycoside, N-glycoside and glycosaminoglycan, in the pro-portion.

Amino Acid Sequence↗
PubMed1993

[An evaluation of prognostic factors in patients with esophageal carcinoma].

We evaluated the relationship between clinicopathological findings and the prognosis of 101 patients who underwent esophagectomy for primary esophageal cancers in our institution, from 1980 to 1991, and investigated the prognostic factors of esophageal carcinoma. There were significant relationships between the prognosis and the depth of cancer invasion (P < 0.05), lymph nodes involvement (P < 0.05), lymphatic invasion (P < 0.01), venous invasion (P < 0.05) and histological stages (P < 0.01). The stages were decided by the depth of invasion and the lymph nodes metastasis. There were also no positive relationships between the prognosis and lymphatic and venous invasion in the patients groups of both n (-) and n3 + 4. Therefore, we concluded that the most important prognostic factors were the depth of cancer invasion (invasion into the neighboring structures) and lymph nodes involvement. We suggest that lymphatic and venous invasion may play an important part in the prognosis of the patients in the n1 + 2 positive group.

Carcinoma, Squamous Cell↗
PubMed1993

Archaebacterial lipids: highly proton-impermeable membranes from 1,2-diphytanyl-sn-glycero-3-phosphocholine.

Unlike ordinary glycero-lipids such as egg-yolk lecithin, 1,2-diphytanyl-sn-glycero-3-phosphocholine, which was employed as a model lipid of archaebacterial acidophiles, gave liposomal membranes which were highly resistant to proton permeation in a wide temperature range (about 10-50 degrees C); the permeability coefficient and activation energy of the flux were 0.7 x 10(-5) cm/s at 20 degrees C and 24.5 kcal/mol, respectively. The high resistance to proton flow was attributed to a fluid and bulky isoprenoid chain-layer of the membrane.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1993

Effect of downstream message secondary structure on the secretory expression of the Streptomyces subtilisin inhibitor.

The contribution of downstream message secondary structure to the production of Streptomyces subtilisin inhibitor (SSI) was investigated in Streptomyces lividans 66 using a cloned gene. By deletion analysis, two inverted repeats located downstream from the stop codon in the SSI gene were found to exhibit a marked effect on the amount and homogeneity of SSI gene transcript and, consequently, the efficiency of SSI productivity.

Bacterial Proteins↗
PubMed1993

Detection of Mg(2+)-dependent endonuclease activity in myeloid leukemia cell nuclei capable of producing internucleosomal DNA cleavage.

We detected Mg(2+)-dependent, Ca(2+)-independent endonuclease activity in non-apoptotic myeloid leukemia cell nuclei using autodigestion method which cleaved the chromatin of the autologous leukemia cells to an oligonucleosomal length pattern. Similar endonuclease activity could be successfully recovered in the protein extracts of the human leukemia cell nuclei. The extracts consistently elicited characteristic DNA cleavage of another leukemia cell (KG-1) nuclei as the target, the enzyme activity of which had been inactivated. We propose that this method is a useful tool for the study of endonucleases involved in apoptosis.

Animals↗
PubMed1993

Isolation of mitochondrial cyclophilin from bovine heart.

Peptidyl-Prolyl cis-trans isomerase was isolated from bovine heart mitochondrial matrix. The enzyme has a M(r) of 19,000 and its activity was inhibited by cyclosporin A (inhibition constant, 6.9 nM), but not by FK-506. The mitochondrial content of the enzyme is in good agreement with the number of binding sites for cyclosporin A (85 pmol/mg of matrix protein). Partial amino acid sequencing showed that the enzyme has a serine-rich N-terminal extension and is similar to human cyclophilin 3 (Bergsma et al. (1991) J. Biol. Chem. 266, 23204-23214) rather than the cytosolic and endoplasmic reticulum isoforms. We conclude that this protein is mitochondrial cyclophilin and a homologue of human cyclophilin 3.

Amino Acid Isomerases↗
PubMed1993

Concordant p53 and DCC alterations and allelic losses on chromosomes 13q and 14q associated with liver metastases of colorectal carcinoma.

To identify genetic alterations associated with acquisition of metastatic ability in colorectal carcinoma, 31 liver metastases and 40 primary tumors of colorectal carcinoma from 55 patients were analyzed for loss of chromosomal heterozygosity using 46 polymorphic DNA markers covering 15 chromosomes. Loss of heterozygosity (LOH) and/or rearrangement at the TP53 and DCC loci were detected in all liver metastases (10 of 10 at TP53 and 19 of 19 at DCC), and were observed in 59% (10 of 17) at TP53 and 75% (18 of 24) at DCC respectively in the primary tumors. Furthermore, the incidence of LOH on chromosomes 13q and 14q was higher than that on other chromosomes in liver metastasis, and it was higher in liver metastases than in primary tumors (20/30 vs. 18/39, p = 0.072 on chromosome 13q and 21/31 vs. 16/40, p = 0.018 on chromosome 14q). In 4 cases, LOH or rearrangement at loci on chromosomes 13q, 14q and 18q not detected in primary tumors was observed in liver metastases from the same patients. These results suggest that concordant p53 and DCC alterations and inactivation of several other tumor-suppressor genes, especially those on chromosomes 13q and 14q, play important roles in the acquisition of metastatic potential of colorectal carcinoma.

Alleles↗
PubMed1993

Ca(2+)-induced, phospholipase-independent injury during reoxygenation of anoxic mitochondria.

Reoxygenation of rat-liver mitochondria after anoxic incubation induced release of matrix proteins. As assessed by release of a matrix enzyme, it was proportional to the rate of H2O2 production. The release was not observed with low concentrations of extramitochondrial free Ca2+, indicating a Ca(2+)-dependent pathway. Phospholipase A2 was not involved in the reoxygenation injury, because non-esterified fatty acids did not increase on reoxygenation even when re-acylation was inhibited and because inhibitors of phospholipase A2 had little effect on enzyme release. Cyclosporin A, ATP, ADP and inhibitors of pyridine nucleotide oxidation had a protective effect, strongly suggesting involvement of so-called Ca(2+)-dependent permeability transition. Ca2+ was also released from reoxygenated mitochondria and inhibition of reuptake of released Ca2+ attenuated the enzyme release. Similar releases of aspartate aminotransferase and Ca2+ were observed with mitochondria in an oxygen radical-generating system, hypoxanthine and xanthine oxidase. In this system, lecithin-cardiolipin liposomes also released entrapped Ca2+ without disruption of the membrane. From these results, we conclude that during reoxygenation, Ca2+ release and subsequent reuptake induced permeability transition of mitochondria, resulting in reoxygenation injury.

Animals↗
PubMed1993

Comparative study of human and rabbit cell infection with cell-free HTLV-I.

Infection of human and rabbit cells with cell-free HTLV-I was studied by PCR analysis. Both human and rabbit PBL were infected similarly by cell-free virus of both human and rabbit cell origin. Cells were infected with the cell-free virus without prior treatment and regardless of the concentration of the culture supernatant containing the virus. Human and rabbit cell lines were also infected similarly by the cell-free virus, the proviral DNA persisting for more than two months. The culture supernatants of HTLV-I-producing cells could thus be a potential cause of laboratory infections.

Animals↗
PubMed1993

Improved leader and putative terminator sequences for high-level production of Streptomyces subtilisin inhibitor in Escherichia coli.

A high-level production system in Escherichia coli for an alkaline serine protease inhibitor, termed Streptomyces subtilisin inhibitor (SSI), from S. albogriseolus S-3253 was established by replacing the SSI signal sequence with the OmpA signal sequence using the inducible pIN-III-ompA vector. Significant amounts of recombinant SSI, resulting from accurate cleavage of the OmpA signal peptide, were accumulated in the periplasmic space or excreted into the culture medium. The inhibitory activity of the processed protein against subtilisin BPN' was identical with that of authentic SSI. Furthermore, deletion of one of the putative dual terminators (terminator 1) resulted in a 1.9-fold increase in production. This effect on SSI gene expression efficiency was found to be governed mainly at the transcription level.

Amino Acid Sequence↗