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Biomedical subjects

N Okamoto

Publications and source records attributed to N Okamoto.

At least 181 records · Page 10Linked to original sources
PubMed1995

Two c-myc genes from a tetraploid fish, the common carp (Cyprinus carpio).

Two c-myc genes have been isolated from a tetraploid fish, the common carp (Cyprinus carpio). The nucleotide (nt) sequences of the two genes and their flanking regions (CAM1, 8675 bp and CAM2, 5784 bp) have been determined. Both genes contain two coding exons which are homologs of c-myc exons 2 and 3 in higher vertebrates. The nt sequence homologous to c-myc exon 1 of higher vertebrates has not been found. Carp CAM1 and CAM2 presumably encode peptides of 394 and 401 amino acids (aa), respectively. These two peptides share 55-91% aa identity with those of humans, chickens, frog, rainbow trout and zebra fish. The two carp c-Myc have a Glu stretch at the beginning region of exon 3. This Glu stretch is also present in zebra fish, suggesting that it may be characteristic to c-myc genes of cyprinid fishes. The existence of two c-myc in carp is attributed to the tetraploid nature of carp. These two genes share 92.4% nt identity in the coding region and 84.2% in the intron. The two deduced peptides share 94.2% aa identity, suggesting that the tetraploid event probably occurred 58 million years ago. Both of the genes' cDNA clones were obtained from a cDNA library of carp peripheral blood leukocytes, implying that both of the genes are expressed.

Amino Acid Sequence↗
PubMed1995

Indocyanine green videoangiographic findings in choroidal metastatic tumor.

BACKGROUND: Indocyanine green videoangiography (ICGV) has recently advanced and become widely available as a clinical tool. We tested the efficacy of ICGV in evaluating metastatic choroidal tumors. METHODS: ICGV using Topcon 50-IA was performed in five patients with clinically diagnosed choroidal metastatic tumors. The findings were compared with those of conventional fluorescein angiography (FAG). RESULTS: Compared with FAG, ICGV demonstrated more smooth and regular hypofluorescent lesions, precisely indicating the exact size of the tumor. In all cases, no tumor vessels were found. The choroidal vascular integrity around the tumors was observed. FAG, however, was more sensitive in detecting the tumor development than ICGV when the extent of the hypofluorescent lesion could be seen clearly in the early phase. FAG provided more information regarding retinal pigment epithelial dysfunction in the outer blood retinal barrier overlying the tumor. CONCLUSION: Since ICGV enables visualization of tumors through the retina, it is very useful, particularly in cases of associated secondary retinal detachment around the tumors. ICGV combined with FAG provides more precise assessment of the tumors themselves and their response to treatment than FAG alone.

Adenocarcinoma↗
PubMed1995

A patient with Schinzel-Giedion syndrome and a review of 20 patients.

The Schinzel-Giedion syndrome is characterized by severe midface retraction, multiple skull anomalies, clubfeet, and cardiac and renal malformations. So far, 20 patients have been reported. This is the first report of the syndrome demonstrated in Oriental patients. In surviving patients, severe growth and developmental deficiency is a common finding.

Abnormalities, Multiple↗
PubMed1995

A new fluorochromasia method using a fluorescence microplate reader for assay of cytotoxic activity of carp leucocytes.

A new fluorochromasia method using a fluorescence microplate reader has been established to assay spontaneous cytotoxic activity of carp leucocytes. This method is characterized by using propidium iodide (PI) for staining dead target cells and a fluorescence microplate reader for measurement of the fluorescence of PI. K562 as target cells were prepared in 96-well flat-bottom microplates, and carp leucocytes were added as effector cells. After 2.5 h incubation, PI was added to each well. After an additional 1.5 h incubation, fluorescence of each well was measured. Correlation between this method and 51Cr-release assay was obtained. The results demonstrated that this new fluorochromasia method can be used to assay cytotoxic activity of carp leucocytes.

Animals↗
PubMed1995

Band 4.2 Komatsu: 523 GAT-->TAT (175 Asp-->Tyr) in exon 4 of the band 4.2 gene associated with total deficiency of band 4.2, hemolytic anemia with ovalostomatocytosis and marked disruption of the cytoskeletal network.

A novel mutation of 523 GAT-->TAT (175 Asp-->Tyr) in exon 4 of the band 4.2 gene was detected in a 37-year-old Japanese patient with total lack of band 4.2 protein, designated as allele 4.2 Komatsu. In this patient, moderate uncompensated hemolytic anemia (red cell count 3.38 x 10(6)/microliters, hemoglobin 10.8 g/dl, hematocrit 30.9%, reticulocytes 12.4%, indirect bilirubin 1.84 mg/dl) with ovalostomatocytosis and increased osmotic fragility had been noted since birth. Family studies revealed no overt hemolytic anemia in other family members, essentially normal red cell morphology, and a normal profile of red cell membrane proteins including band 4.2. Genetic studies proved that the proband was homozygous and all the family members studied were heterozygous with respect to the mutation of 523 GAT-->TAT of the band 4.2 gene. Although band 4.2 was completely absent in the proband, trace amounts of 72 kDa and 74 kDa peptides were detected in the red cells of all the family members, in which the mutation of 424 GCT-->ACT at exon 3 of the band 4.2 gene (Nippon type) was not present. Electron microscopic studies with the surface replica method and the quick-freeze deep-etching method showed the most marked disorganization of the cytoskeletal network in the patient's red cells in situ among the cases of band 4.2 deficiencies we have studied. This suggests that the amino acid of the band 4.2 protein, which was affected by the present mutation in exon 4, is much more crucial for the functioning of band 4.2 protein than that at codon 142 in exon 3. The cytoplasmic domain of band 3 in the proband's red cells was essentially normal in protein chemistry and in gene analysis with single-stranded conformation polymorphism (SSCP).

Adult↗
PubMed1995

Band 4.2 Shiga: 317 CGC-->TGC in compound heterozygotes with 142 GCT-->ACT results in band 4.2 deficiency and microspherocytosis.

A novel compound heterozygous mutation of 317 CGC-->TGC with 142 GCT-->ACT in human red cell band 4.2 deficiency is described. A proband and his son suffered from compensated haemolysis with nearly complete deficiency of red cell band 4.2. Their red cell morphology exhibited microspherocytosis resembling classic hereditary spherocytosis (HS). Sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed band 4.2 to be nearly missing (< 1% of normal controls) with the presence of 74 kD and 72 kD isoforms in trace amounts. Other family members (daughters older and younger than the son) exhibited nearly normal amounts of 72kD as a wild form of band 4.2 on SDS-PAGE with the presence of the 74kD isoform in a trace amount. The proband and his son demonstrated two compound heterozygous mutations in trans: i.e. nucleotide (nt) 949 CGC-->TGC (codon 317 Arg-->Cys) in exon 7 and nt 424 GCT--ACT (codon 142 Ala-->Thr) in exon 3 of the band 4.2 gene. The two daughters demonstrated only the mutation of nt 949 CGC-->TGC in exon 7 in heterozygous states, but no 142 mutation. Therefore the proband and his son were compound heterozygotes of these two mutations in trans. It is interesting to note that the 74 kD isoform of band 4.2 protein existed in a trace amount in the two daughters in spite of the absence of the 142 Ala-->Thr mutation. In addition, even in the presence of the 142 mutation in one allele in the proband and his son, their red cell morphology demonstrated classic HS with microspherocytosis, although a homozygous state of the 142 mutation known as the Nippon type of band 4.2 deficiency exhibits ovalostomatocytosis.

Aged↗
PubMed1995

Expression of intercellular adhesion molecule 1 on pancreatic beta-cells accelerates beta-cell destruction by cytotoxic T-cells in murine autoimmune diabetes.

Intercellular adhesion molecule 1 (ICAM-1) plays an important role in the pathogenesis of insulin-dependent diabetes mellitus (IDDM) by being involved in the extravasation of lymphocytes from the circulation into the inflamed pancreas. However, the mechanism of beta-cell destruction by which expression of ICAM-1 on beta-cells may facilitate adhesion of effector cells still remains to be elucidated. Several lines of evidence suggest that this adhesion molecule is involved in the destruction of pancreatic beta-cells by killer lymphocytes in the NOD mouse, which shows an autoimmune diabetic syndrome similar to that of human IDDM. Immunohistochemical study under light microscopy demonstrated that all of the mononuclear cells infiltrating the islets strongly expressed ICAM-1 and leukocyte function-associated antigen 1 (LFA-1), a counterreceptor of ICAM-1, whereas ICAM-1 expression on islet cells was not apparent. However, immunohistochemical staining under electron microscopy revealed that islet beta-cells adjacent to infiltrating lymphocytes were clearly stained by an anti-ICAM-1 monoclonal antibody (mAb). Flow cytometric analysis showed that the ICAM-1 expression on NOD islet cells and NOD-derived insulinoma cells (MIN6N8a) was inducible by interferon (IFN)-gamma or tumor necrosis factor-alpha. These cytokines had an additive effect on the ICAM-1 induction. Susceptibility of MIN6N8a cells to lysis by a NOD islet-derived CD8+ cytotoxic T-cell clone was greatly enhanced by IFN-gamma pretreatment, and this enhancement was abolished by anti-ICAM-1 and anti-LFA-1 mAbs. When both mAbs were administered into NOD mice with spontaneous or adoptively transferred diabetes, the development of diabetes was significantly prevented.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Optic disc and choroidal circulation detected by dye-filling rate in indocyanine green angiography].

Dye-filling rate of optic disc and choroid in normal human subjects was investigated using indocyanine green infra-red videoangiography and computerized image analysis. Only relative changes in the circulation of disc and choroid could be studied and the ratio (D/M) of dye-filling rate in normal subjects (age ranged 23-62) in disc (D) to choroid (M) was reliable. Intraocular pressure (IOP) was elevated to two levels with a pneumatic suction-cup. When D/M at normal IOP was 1, mean D/M was 1. 29 when mean IOP was 26.8 mmHg, and 1.48 when mean IOP was 38.4 mmHg. The results suggest that IOP elevation produced less change in the disc circulation than in the choroid. The ratio of dye-filling rate of the disc at 38.4 mmHg to normal IOP was significantly correlated (P < 0.05) with perfusion pressure at normal IOP, showing that the autoregulatory mechanisms in the disc blood flow may possibly reach the limit especially in subjects whose perfusion pressure is low.

Adult↗
PubMed1994

[Estimation of vasopressin treatment in the upper GI bleeding using Doppler flowmetry].

The effect of intravenous vasopressin infusion in 5 patients with upper GI bleeding was studied by measuring portal blood flow velocity with pulsed Doppler ultrasound technique. In 4 of 5 patients portal blood flow velocity decreased at 1 hr after vasopressin infusion. In all patients the velocity decreased at 24 or 48 hrs. We think doppler is safe and useful method in the evaluation of vasopressin infusion therapy.

Adult↗
PubMed1994

Developmentally regulated postsynaptic localization of a metabotropic glutamate receptor in rat rod bipolar cells.

The retinal bipolar cell receiving glutamate transmission from photoreceptors mediates a key process in segregating visual signals into ON center and OFF center pathways. This transmission involves a G protein-coupled metabotropic glutamate receptor (mGluR). Immunocytochemical and immunoelectron microscopic studies indicate that restricted localization of a specific mGluR subtype, mGluR6, at the postsynaptic site of the rat rod bipolar cell. This specialization is developmentally regulated: mGluR6 is initially distributed in both the soma and dendrites and is finally concentrated on the postsynaptic site. The mGluR6 localization is reversed when photoreceptors degenerate in the mutant rat with retinal dystrophy. Evidence is thus presented indicating specialized, developmentally regulated receptor distribution in the central nervous system and the crucial role of mGluR6 in photoreceptor-bipolar cell synaptic transmission.

Amino Acid Sequence↗
PubMed1994

Expression of mRNAs of L-AP4-sensitive metabotropic glutamate receptors (mGluR4, mGluR6, mGluR7) in the rat retina.

Expression patterns of mRNAs of L-AP4-sensitive metabotropic glutamate receptors (mGluR4, mGluR6, mGluR7) in the rat retina were examined by northern blot analysis and in situ hybridization histochemistry. Expression patterns of mGluR4 and mGluR7 mRNAs were quite different from that of mGluR6 mRNA which was expressed at the outer part of the inner nuclear layer. The mGluR4 mRNA was expressed on the cell bodies of the ganglion cells, but not in the inner or outer nuclear layer. The expression of mGluR7 mRNA was observed throughout the entire region of the inner nuclear layer and on the cell bodies of the ganglion cells.

Aminobutyrates↗
PubMed1994

Molecular characterization of a new metabotropic glutamate receptor mGluR7 coupled to inhibitory cyclic AMP signal transduction.

A cDNA clone for a new rat metabotropic glutamate receptor termed mGluR7 was isolated through polymerase chain reaction-mediated DNA amplification by using primer sequences conserved among the metabotropic receptor (mGluR) family and by the subsequent screening of a rat forebrain cDNA library. The cloned mGluR7 subtype consists of 915 amino acid residues and exhibits a structural architecture common to the mGluR family with a large extracellular domain preceding the seven putative membrane-spanning domains. mGluR7 shows the highest sequence similarity to mGluR4 and mGluR6 among the members of the mGluR family. Similar to mGluR4 and mGluR6, mGluR7 inhibits forskolin-stimulated cyclic AMP accumulation in response to agonist interaction and potently reacts with L-2-amino-4-phosphonobutyrate and L-serine-O-phosphate in Chinese hamster ovary cells transfected with the cloned cDNA. RNA blot and in situ hybridization analyses of mGluR7 mRNA indicated that it is widely expressed in many neuronal cells of the central nervous system and is thus different from the more limitedly expressed mGluR4 or mGluR6 mRNA. mGluR7 together with mGluR4 thus corresponds to the putative L-2-amino-4-phosphonobutyrate receptor which plays an important role in modulation of glutamate transmission in the central nervous system.

Amino Acid Sequence↗
PubMed1994

Diagnosis of carbohydrate-deficient glycoprotein syndrome by matrix-assisted laser desorption time-of-flight mass spectrometry.

Serum transferrin from patients with carbohydrate-deficient glycoprotein syndrome was analysed by matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF mass spectrometry). Abnormal molecular species with a defect of one or two oligosaccharide chains of 2200 Da were clearly identified. MALDI-TOF mass spectrometry will serve to diagnose this aetiologically unknown, metabolic disease.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1994

Laser desorption time-of-flight mass spectrometric analysis of transferrin precipitated with antiserum: a unique simple method to identify molecular weight variants.

Serum transferrin precipitated with anti-transferrin serum was analysed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS). The transferrin-antibody complex in the immunoprecipitates was separated into transferrin and IgG in an acidic pH, which is the usual condition of loading on MALDI-TOFMS. Ions of IgG and other minor components were not superimposed on the transferrin ions. Transferrin isoforms with different carbohydrate contents could be identified by this simple method easier than by affinity chromatography requiring the time-consuming preparation of an insolubilized specific antibody. The transferrin isoform with a molecular weight of approximately 2.2 kDa smaller than normal transferrin, which is contained in the serum from patients with carbohydrate-deficient glycoprotein (CDG) syndrome, was identified by this method. In addition to the M(1+) ion detected using sinapinic acid as a matrix, the M(2+) and M(3+) ions of transferrin were clearly detected using alpha-cyano-4-hydroxycinnamic acid as matrix and the molecular weight heterogeneity was identified more clearly in multivalent ions than that in the M(1+) ion. The MALDI-TOF analysis of immunoprecipitates may serve as a simple and sensitive method to identify the molecular weight heterogeneity of various biological materials.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1994

Homogeneous fluorescence detection method for human leukocyte antigen-DR typing following polymerase chain reaction amplification with sequence-specific primer.

A fluorescent homogeneous method for the detection of sequence-specific amplification of human leukocyte antigen (HLA) alleles has been developed. In this approach, polymerase chain reaction sequence-specific primers (PCR-SSP) are used to amplify DRB1, DRB3, and DRB4 alleles. Lambda exonuclease and Exonuclease I are added to reduce background by digesting template DNA, partial primer dimer, and primer. PCR amplicons are then detected following the addition of a fluorescent dye (thiazole yellow dimer) which binds to double-stranded DNA. No transfer or wash steps are required. Thus, the risk of sample contamination, which is a major source of inaccuracy for DNA amplification methods, is greatly reduced. This approach is also faster and more easily automated than the standard approach using gel electrophoresis and ethidium bromide staining. Speed and automation are important considerations for HLA typing since the number of possible alleles for each HLA type is substantial. A homogeneous HLA-SSP typing method may be especially useful for clinical labs doing large numbers of samples and for the eventual automation of HLA DNA typing.

Alleles↗
PubMed1994

A Japanese patient with the Costello syndrome.

The Costello syndrome is characterized by dwarfism, unique cutaneous lesions, distinct facial gestalt, and mental retardation. We present a Japanese patient with the Costello syndrome. She showed high serum IgM level during the early infantile period. Nissen's fundplication was carried out to treat severe gastroesophageal reflux. Endocrinological investigations revealed a partial deficiency of growth hormone.

Abnormalities, Multiple↗