Biomedical subjects

S Miyazawa

Publications and source records attributed to S Miyazawa.

At least 19 recordsLinked to original sources

PubMed1992

Carboxyl-terminal consensus Ser-Lys-Leu-related tripeptide of peroxisomal proteins functions in vitro as a minimal peroxisome-targeting signal.

The minimal sequence requirement for a peroxisome-targeting signal was investigated using an in vitro import system. Carboxyl-terminal sequences Ser-Lys-Leu (SKL) and Leu-Gln-Ser-Lys-Leu (LQSKL) of acyl-CoA oxidase (AOX) directed to peroxisomes the fused proteins with import-incompetent forms of AOX and catalase that had been truncated, implying that the SKL tripeptide functions as a targeting signal. Elimination of the entire SKL sequence or deletion of any 1 or 2 amino acids in the sequence abolished the import activity of AOX. Substitution of alanine for serine did not affect the import activity. Topogenic activity was retained when lysine was mutated to either arginine or histidine, whereas mutation to glutamic acid completely abolished the activity. A synthetic peptide comprising the carboxyl-terminal 10 amino acid residues of AOX inhibited the import of the authentic AOX polypeptide, whereas other peptides in which SKL was mutated, deleted, or internally located were not effective. The uptake of AOX was little affected by the peptide with an amidated alpha-carboxyl group. These results strongly suggest that the carboxyl-terminal SKL motif sequence (Ser/Ala)-(Lys/Arg/His)-Leu functions as a topogenic signal in translocation of proteins into peroxisomes, requiring the whole tripeptide sequence with a free alpha-COOH group at the carboxyl terminus.

Acyl-CoA Oxidase↗

PubMed1992

Electron microscopic X-ray microanalysis of metals deposited in oral mucosa.

A 35-year-old woman exhibited bluish-brown discoloration of her buccal mucosa suggesting malignant melanoma. Histopathological examination revealed that the pigment was not melanin but caused by metal deposits. Electron microscopically, metallic particles were located on the lamina densa of basal laminae at mucosal epithelium, nerve fibers, and blood vessels and on the microfilaments of elastic fibers as well as in macrophages and fibroblasts. Electron microscopic point X-ray microanalysis revealed that these metallic particles were composed of Ag, Se, Fe, Co, Cu, and S. Analysis suggests that these metals were derived from dental amalgam and that the discoloration was caused by amalgam tattoo.

Adult↗

PubMed1992

Hapten synthesis for (+)-6-(2-chlorophenyl)-3-cyclopropanecarbonyl-8,11-dimethyl-2,3,4,5-tet rahydro-8H-pyrido[4',3':4,5]thieno[3,2-f] triazolo[4,3-a][1,4]diazepine (E6123).

(+)-6-(2-Chlorophenyl)-3-cyclopropanecarbonyl-8,11-dimethyl-2,3,4, 5-tetrahydro-8H-pyrido[4',3':4,5]thieno[3,2-f]triazolo[4,3-a] [1,4]diazepine (E6123) is a very potent platelet-activating factor (PAF) receptor antagonist and shows potent anti-PAF activities at the microgram level in a variety of animal models. In order to examine the pharmacokinetics of E6123 at low doses, establishment of a radioimmunoassay is required. On the basis of the metabolic pattern of E6123, we synthesized 6-[2-chloro-4-(3-carboxypropyl) phenyl]-3-cyclopropanecarbonyl-8,11-dimethyl-2,3,4,5-tetrahydro-8H -pyrido[4',3':4,5]thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepine 22 as a potential hapten. In the synthesis of 22, we developed butynyl carbamate as a piperidine ring N-protecting group to prevent possible side reaction, namely oxidation of the methylene at position 2. This protecting group is stable under usual basic and acidic conditions.

Azepines↗

PubMed1992

Pitfalls in the double labelling immunoelectron microscopy using one face of the grid.

We compared two procedures in the double labelling immunoelectron microscopic method of hormone-storing cells: one-faced and two-faced procedures. With the two-faced procedure we got convincing results consistent with morphological finding, while we often got false results with the one-faced procedure. By the misleading one-faced procedure, the cell storing any one hormone will be misinterpreted as a multihormone storing cell. Therefore, it is concluded that the two-faced method is safer for the double labelling immunoelectron microscopic study.

Amylases↗

PubMed1992

[A case with cerebral embolism due to the recurrence of thrombotic valve five years after the reoperation].

Between April 1972 and May 1990, a total of 300 patients in our institution underwent insertion of a Björk-Shiley aortic valve prosthesis, and development of a thrombosed valve was observed only in 4 female cases. It was considered that the thrombosed valves in all 4 cases were caused by inadequacy of the anticoagulant agents. As reoperative procedures, thrombectomy, resection of the excessive granulation under the valve, and a method of turning the opening direction of the valve 180 degrees were used. These procedures were reported previously. One case died late in the day after the operation, while the remaining 3 cases progressed favorably. Although control of one of these three cases was favorably maintained after reoperation, a restriction of 43.2 degrees of the opening angle of the valve was again observed by valve-fluoroscopy performed in the 3rd postoperative year. However, progress of this patient was observed on an outpatient basis because flow velocity at the position of aortic valve was also within normal range. This was shown Doppler's test using ultrasonic waves and the patient showed no symptoms. However, this patient was admitted to our institute due to sudden right hemiplegia on May 1990 in the 5th year after reoperation. The cerebral embolism due to the recurrent thrombosed valve was diagnosed because a low density in the middle cerebral area was observed by CT, and increase of the opening angle of the valve (compared with that at ambulation) was also noted by valve-fluoroscopy. The hemiplegia remained even though this patient was saved from death. (ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗

PubMed1992

[Right aortic arch with mirror-image branching and coarctation of the aorta--a case report].

The right aortic arch with coarctation of the aorta was reported. A 56-year-old woman admitted to the hospital because of headache and hypertension. Cardiac catheterization revealed the right aortic arch with coarctation of the aorta and 80 mmHg pressure gradient across the coarctation. The bypass operation with a 14 mm Dacron graft between the ascending to descending aorta was performed. There was no peak systolic pressure gradient between the ascending and descending aorta after bypass operation. This patient is the fourth case report with both mirror-image type right aortic arch and coarctation of the aorta.

Aorta, Thoracic↗

PubMed1991

Amino-terminal presequence of the precursor of peroxisomal 3-ketoacyl-CoA thiolase is a cleavable signal peptide for peroxisomal targeting.

To examine the function of the amino-terminal presequence of rat peroxisomal 3-ketoacyl-CoA thiolase precursor, fusion proteins of various amino-terminal regions of the precursor with non-peroxisomal enzymes were expressed in cultured mammalian cells. On immunofluorescence microscopy, all constructs carrying the presequence part exhibited punctate patterns of distribution, identical with that of catalase, a peroxisomal marker. Proteins lacking all or a part of the prepiece were found in the cytosol. These results indicate that the presequence of the thiolase has sufficient information for peroxisomal targeting.

Acetyl-CoA C-Acyltransferase↗

PubMed1991

Structure-activity studies on triazolothienodiazepine derivatives as platelet-activating factor antagonists.

A series of triazolodiazepines was synthesized and evaluated for anti-platelet activating factor (PAF) activities. Structure-activity relationship (SAR) studies on this series revealed that the introduction of a methyl group into the 8-position of the thienodiazepine nucleus can lead to a lengthening of the duration of action. Introduction of a methyl group produced an asymmetric center and the enantiomers so formed were separated with an optical resolving column. In the in vitro assay system, the (+)-isomers displayed 50-200 times more potent anti-PAF activity than the (-)-isomers. After comparison of toxicology and pharmacokinetics, (+)-6-(2-chlorophenyl)-3- cyclopropanecarbonyl-8,11-dimethyl-2,3,4,5-tetrahydro-8H-pyrido[4' ,3':4,5]thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepine (35(+)-isomer, E6123) was selected from among the compounds synthesized as a candidate for clinical study.

Animals↗

PubMed1990

Effects of a novel PAF antagonist, E6123, on PAF-induced biological responses.

E6123 is a new member of the benzodiazepine class of PAF antagonists. Although it has similar activity in vitro to the two representative antagonists WEB2347 and Y24180, in vivo it is far more active than these compounds. Thus E6123 was effective in inhibiting dose-dependently PAF-induced bronchoconstriction when administered orally or intravenously (IC50 1.0 and 1.3 micrograms/Kg, respectively, at 3 hr), and had a minimum effective dose of 10 micrograms/Kg and 3 micrograms/Kg, respectively, against PAF-induced hematoconcentration and edema at 3 hr after oral administration. Furthermore, E6123 protects mice from PAF-induced death dose-dependently (ED50 7 micrograms/Kg at 3 hr). In conclusion, E6123 should prove valuable in pharmacological and clinical research into the roles of PAF, and in therapy of diseases such as asthma, in which PAF is assumed to play a pathological role.

Animals↗

PubMed1990

Effects of a novel PAF antagonist, E6123, on passive anaphylaxis.

E6123 inhibited antigen-induced bronchoconstriction, the development of bronchial hyperreactivity and eosinophil infiltration in the airway in passively sensitized guinea pigs and protected mice from anaphylactic death. The inhibitory effects of E6123 on anaphylactic response were very potent compared with those of WEB 2347 and Y-24180.

Anaphylaxis↗

PubMed1990

Basigin, a new, broadly distributed member of the immunoglobulin superfamily, has strong homology with both the immunoglobulin V domain and the beta-chain of major histocompatibility complex class II antigen.

Lotus tetragonolobus agglutinin (LTA) binds preferentially to early embryonic cells in the mouse. The affinity-purified antibody raised against LTA receptors from embryonal carcinoma cells were used to screen a lambda gt11 expression library of F9 embryonal carcinoma cells, resulting in detection of a cDNA clone specifying a new glycoprotein termed "basigin." The glycoprotein has been suggested to be a transmembrane one, and was found to be a new member of the immunoglobulin (Ig) superfamily. The molecular weight of basigin was largely in the range between 43,000 and 66,000, while that of the peptide portion with a putative signal sequence was inferred to be about 30,000. Significant levels of basigin mRNA were detected not only in embryonal carcinoma cells, but also in mouse embryos at 9-15 days of gestation and in various organs of the adult mouse. The Ig-like domain of basigin is unique, since it has strong homology to both the beta-chain of major histocompatibility class II antigen and the Ig V domain. The number of amino acids between the two conserved cysteine residues is intermediate between those of the Ig V and C domains. Therefore, basigin is an interesting protein in connection with the molecular evolution of the superfamily.

Amino Acid Sequence↗

PubMed1990

Pharmacological activities of a novel thienodiazepine derivative as a platelet-activating factor antagonist.

(S)-(+)-6-(2-Chlorophenyl)-3-cyclopropanecarbonyl-8,11- dimethyl - 2,3,4,5 - tetrahydro - 8H - pyrido[4',3':4,5] thieno[3,2-fl-[1,2,4]triazolo]4,3-a][1,4]diazepine (E-6123) is a newly synthesized platelet-activating factor (PAF) antagonist. The effects of E-6123 on in vitro and in vivo PAF-induced responses were investigated. The IC50 values of E-6123 on 3H-PAF binding to human and guinea pig platelets were 2.7 and 3.0 nmol/l, respectively, and those on PAF-induced platelet aggregation in platelet-rich plasma of human, guinea pig and beagle dog were 10.1, 14.7 and 16 nmol/l, respectively. Oral administration of E-6123 at 3 and 10 micrograms/kg to dogs inhibited ex vivo PAF-induced platelet aggregation in a dose-dependent manner. In guinea pigs, E-6123 at 3 micrograms/kg completely inhibited ex vivo PAF-induced platelet aggregation up to 8 h and the inhibition was still significant at 24 h after administration. Occupancy of the platelet PAF receptor by E-6123 at 3 h and 24 h after administration amounted to 80% and 56%, respectively. Bronchoconstriction induced by PAF injection in guinea pigs was inhibited dose-dependently by oral or intravenous administration of E-6123 at similar doses. The IC50 value of E-6123 at 3 h after oral administration was 1 microgram/kg. Oral administration of E-6123 at 3 micrograms/kg inhibited the bronchoconstriction by more than 90% up to 8 h. Hemato-concentration induced by PAF injection in guinea pigs was inhibited by oral administration of E-6123 at 10 micrograms/kg. E-6123 also protected mice from PAF injection-induced death in a dose-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1990

[A comparative study of myocardial scintigraphy with 99mTc-SQ-30,217 and 201Tl in cases with myocardial infarction].

A comparative study of myocardial scintigraphy with 99mTc-SQ-30217 (SQ) and 201Tl was performed in 6 patients having ischemic heart diseases which were confirmed by the coronary angiography. The SQ study was done 1 week after the 201Tl study. Both studies were performed in exercise and resting state. Degree of perfusion defect was compared between SQ and 201Tl SPECT by means of scoring 0-2 (0: no defect, 1: equivocal, 2: definite defect) by five doctors (two physicians and three radiologists). Ability of this agent to detect the ischemic lesions was similar to that of 201Tl except for two regions. Effect of the liver image on the evaluation of the inferior wall of the left ventricle was small on this study, although the hepatic accumulation of the tracer was prominent. This agent is a promising tracer for the evaluation of myocardial perfusion in the cases with myocardial infarction.

Heart↗

PubMed1990

[The relation among the life style and the clinical laboratory data].

The concept of risk pattern is introduced as the new point of view for the cancer prevention. The risk pattern should be got by drawing out the feature of the human information composed of dietary habit, life style, family history, laboratory data. Using the large scale health screening data in Nagano (total population = 93, 403, 1,140 byte/person), the risk pattern is analysed and the relation among the variables are discussed.

Analysis of Variance↗

PubMed1990

[Doppler echocardiographic measurement of flow velocity in cases with a Björk-Shiley aortic prosthesis and diagnosis of prosthetic valve dysfunction].

115 patients with a Björk-Shiley aortic valve prosthesis were studied by means of the ultrasonic Doppler method. The maximum flow velocity at the prosthetic valve was measured by the continuous wave Doppler method, and the velocity at the left ventricular outflow tract was measured by the pulsed wave Doppler method. In addition, flow velocity measured by Doppler method was compared to the valve opening angle obtained by cinefluoroscopy. 1) The maximum velocities at the prosthetic valve in the patients with normally functioning prosthesis were 3.1 +/- 0.4, 2.7 +/- 0.5, 2.2 +/- 0.4, 1.9 +/- 0.3, 1.7 +/- 0.3 m/sec for valve sizes of 21, 23, 25, 27, and 29 mm, respectively. Statistical differences were recognized between the valve size groups. In a case with a thrombosed valve, the maximum velocity was faster than in cases with normally functioning valves and it reached 4.5 m/sec. 2) Flow velocities at the left ventricular outflow tract in patients with normally functioning valves were 0.86 +/- 0.15, 0.86 +/- 0.16, 0.79 +/- 0.14, 0.82 +/- 0.16, 0.75 +/- 0.18 m/sec for valve sizes of 21, 23, 25, 27, 29 mm, respectively. No statistical difference was recognized. In the patients with perivalvular leakage, velocity was faster than in the patients with normally functioning valves. But, in the case with thrombosed valve, it remained within the normal range. 3) No significant correlation was observed between flow velocities and valve opening angles in the cases with normally functioning valves. But, in the cases with malfunctioning valves, flow velocities were faster than normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1989

Only DFL16, DSP2, and DQ52 gene families exist in mouse immunoglobulin heavy chain diversity gene loci, of which DFL16 and DSP2 originate from the same primordial DH gene.

In mice, 12 germ-line DH genes belonging to three different families (DQ52, DSP2 and DFL16) have been identified. The DH genes other than DQ52 are clustered in the 60 kb-long region located between VH and JH genes. Since there are seven DH gene families (DHQ52, DXP, DA, DK, DN, DM and DLR) in humans, we tried to identify new DH gene families in the 60 kb-long region using human DH gene probes. Mouse and human DH genes showing the highest similarity were mouse DFL16 genes and human DA genes. Southern hybridization of the mouse clones covering the 60-kb region with human DH probes did not detect any other DH genes. Nucleotide sequence analysis of the 4.0-kb fragment containing the DFL16.1 gene confirmed this conclusion. Comparison of the 12 germ-line DH genes and more than 150 somatic DH sequences also indicated that there are not more germ-line DH genes in the mouse genome. Moreover, comparison of nucleotide sequences of DFL16.1 and DSP2.2 genes and their surrounding regions suggests that both DH gene families originate from the same primordial DH gene. Using the flanking sequences of both DH genes, the divergence date between DFL16 and DSP2 genes was estimated at around 37 million years ago.

Animals↗

PubMed1989

Peroxisome targeting signal of rat liver acyl-coenzyme A oxidase resides at the carboxy terminus.

To identify the topogenic signal of peroxisomal acyl-coenzyme A oxidase (AOX) of rat liver, we carried out in vitro import experiments with mutant polypeptides of the enzyme. Full-length AOX and polypeptides that were truncated at the N-terminal region were efficiently imported into peroxisomes, as determined by resistance to externally added proteinase K. Polypeptides carrying internal deletions in the C-terminal region exhibited much lower import activities. Polypeptides that were truncated or mutated at the extreme C terminus were totally import negative. When the five amino acid residues at the extreme C terminus were attached to some of the import-negative polypeptides, the import activities were rescued. Moreover, the C-terminal 199 and 70 amino acid residues of AOX directed fusion proteins with two bacterial enzymes to peroxisomes. These results are interpreted to mean that the peroxisome targeting signal of AOX residues at the C terminus and the five or fewer residues at the extreme terminus have an obligatory function in targeting. The C-terminal internal region also has an important role for efficient import, possibly through a conformational effect.

Acyl Coenzyme A↗

PubMed1989

[2-dimensional and Doppler echocardiographic follow-up on degenerative changes in Ionescu-Shiley pericardial xenograft].

Using Ionescu-Shiley pericardial xenograft (ISPX), mitral and tricuspid valve replacement was performed on 64 cases during a period of time 1980-1984. On 48 of these 64 cases, ISPX was followed up and observed for its secular change using 2-dimensional echocardiography and ultrasonic Doppler method. The results revealed the following: 1) For ISPX at the mitral position, incidence of obvious cuspal hypertrophy or calcification was 5, 31, and 46% for 3, 5, and 6 years, respectively. 2) Including up to fine changes such as only a slight increase of echo brightness, rate of change detection was as high as 15, 28, 52, and 61% for 2, 3, 5, and 6 years, respectively. 3) Maximum velocity at the left ventricular inflow tract was 1.2-1.5 m/s and remained unchanged so long as ISPX has normally been functioning. Once regurgitation occurred, the flow velocity become greater, and those cases in which it reached 2 m/s needed re-placement. 4) Obvious cuspal hypertrophy showed a tendency to occurring mainly at those cusps which were situated anterior (on the side of outflow tract of left ventricle) regardless of the inserting direction of the prosthetic valve. 5) Five ISPXs at the tricuspid position showed no abnormality. Of 64 cases, 6 (9.4%) showed valvular dysfunction, and even those cases which showed no such dysfunction proved to be subjected to cuspal degeneration at a high rate. For prosthetic valve replacement by ISPX, both frequent examinations by means of echocardiography and Doppler method and careful observation of the course are necessary.

Adult↗