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Biomedical subjects

M Ozawa

Publications and source records attributed to M Ozawa.

At least 109 records · Page 6Linked to original sources
PubMed1996

[A case of surgically treated hypertrophic obstructive cardiomyopathy suffering from angina pectoris during hemodialysis].

Surgical procedure for hypertrophic obstructive cardiomyopathy (HOCM) in a patient chronic hemodialysis has not been reported in Japan. This is a case report of a 61-year-old male who had been suffering from angina pectoris during hemodialysis. Cardiac catheterization showed a systolic pressure gradient of 79 mmHg at the left ventricular outflow tract and left ventriculogram demonstrated severe mitral regurgitation. He underwent mitral valve replacement and left ventricular myectomy with hemodialysis and extracorporeal ultrafiltration method during cardiopulmonary bypass. Postoperative catheterization showed a decrease of pressure gradient to 19 mmHg at the left ventricular outflow tract, and relief of angina was obtained.

Angina Pectoris↗
PubMed1996

[Infections mononucleosis with pleural effusion].

A 24-year-old man was admitted to our hospital for further examination of pleural effusion. On physical examination, he had a temperature of 39 degrees C, the pharynx was painful and liver and spleen were enlarged. The leukocyte count was 5,700/microliters (atypical lymphocyte 6%). The serum LDH, GOT, GPT, ALP and gamma-GTP levels were elevated, and antibodies to Epstein-Barr viral capsid, early, and nuclear antigens were diagnostic of a primary Epstein-Barr virus infection. The CD4/CD8 ratio of peripheral blood lymphocyte was decreased to 0.2. The pleural effusion was exudate, and infiltration of mononuclear cells was noted. The CD4/CD8 ratio of lymphocytes in the effusion also was decreased to 1.1. The result of pleural biopsy showed a perivascular infiltration of mononuclear cells and immunological stain showed that the infiltrated cells were dominantly T-lymphocytes (about 90%). These findings suggested that the pathogenesis of pleural effusion in infectious mononucleosis was a pleulitis due to the infiltration of T-lymphocytes. Pleural effusion is known as a rare complication of infectious mononucleosis.

Adult↗
PubMed1996

[Interference of antibody reaction with porcine pancreatic amylase in enzymatic assay of total calcium].

Unreliable results were obtained in an enzymatic assay of total calcium (Ca) in a patient's serum using porcine pancreatic amylase (PPA). Besides, the result was different from that obtained by the atomic absorption analysis. Fractionation of the patient's serum by ultrafiltration and Sephadex G-200 gel filtration revealed the presence of an interference substance with a large molecular size of more than 200kDa. This interference substance was absorbed on a Protein A column. Furthermore, an immune precipitate was observed between the patient's serum and PPA by Ouchterlony double immunodiffusion. An antibody against PPA may exist in the patient's serum and interfere with the enzymatic assay of Ca using PPA.

Aged↗
PubMed1996

Immunohistochemical localization of cytosolic sialidase in photoreceptor cells.

The binding sites of the antibody to cytosolic sialidase on the rat and monkey photoreceptor cells were examined immunohistochemically using the avidin-biotinylated peroxidase method. In the rat photoreceptor cells, the antibody bound diffusely to the inner segment and the outer nuclear layers which are composed chiefly of rod cells. In the monkey photoreceptor cells, the antibody bound to the rod inner segments which were clearly distinct, morphologically, from the cone inner segments. The antibody also bound to the rod cell bodies in the outer nuclear layer. These binding patterns show that the antibody bound preferentially to rod photoreceptor cells. This observation is consistent with previous lectin histochemical findings that sialoglycans are preferentially present on the surfaces of rod photoreceptors, and in the rod-associated interphotoreceptor matrix. Sialidase in rod inner segments may function by balancing with sialyltransferase, also preferentially expressed in rod inner segments, to form sialyl residues on the termini of sugar chains in the rod-associated sialoglycoconjugates.

Animals↗
PubMed1996

HLA matching.

1. HLA matching exerts a profound influence on graft outcome. The difference in 3-year graft survival rates between best and worst matched cases was 17% for first grafts and 18% for retransplants. This HLA matching effect persists despite recent improvements in graft outcome. The matching effect at 3-years was 12% for transplants since 1991. 2. Surprisingly, HLA matching is especially important for recipients over age 60. The increase in the HLA matching effect to 20% in patients older than 60 can be attributed to the additive effects of HLA matching on both functional and patient survival. Consequently, graft survival for zero-MM recipients is similar for patients older and younger than age 60. 3. The difference in 3-year survival between zero and 0-MM kidneys was 10% for White and 15% for Black recipients. 4. Transplants with zero-broad but split A,B mismatches had graft outcomes similar to one-A,B,DR MM kidneys. Split DR MM did not affect the outcome of zero-MM kidneys. 5. HLA-matched transplants can be classified according to the degree of identity between the donor and recipient: 6-antigen match, phenotypic match, and zero-MM. Outcome for zero-MM was lower in transplants before 1990, but the 3 types have similar outcomes in recent transplants. The change in UNOS matching policy in 1995 to include zero-MM kidneys doubled the number of shared kidneys. 6. HLA typing from over 150 centers resulted in an error rate for shipped kidneys of less than 5%. Donor antigens retyped at the recipient center resulted in identical antigens for 70% of cases, a broad DR MM for 2.2%, and an A,B MM in 2.6% of the retyped cases. 7. Although increasing cold ischemia time (CIT) had a deleterious effect on survival of MM kidneys, no effect was seen for zero-MM kidneys. 8. An effect of a possible sex-linked minor histocompatibility antigen was demonstrated with improved outcome for male to male zero-MM cadaveric and parent-to-child transplants. 9. Zero-MM kidneys from pediatric donors and donors older than 60 years of age had poorer outcome than MM kidneys before 1991, but the recent experience shows a matching effect even with these marginal donors.

Adult↗
PubMed1995

A novel point mutation in the mitochondrial tRNA(Ser(UCN)) gene detected in a family with MERRF/MELAS overlap syndrome.

We found a new point mutation in the mitochondrial tRNA(Ser(UCN)) gene in a family with MERRF/MELAS overlap syndrome by screening for heteroplasmy by means of chemical cleavage of mismatch (CCM). Our strategy was based on the previous observations that most pathogenic mtDNA mutations in mitochondrial encephalomyopathies are heteroplasmic, whereas almost all neutral mitochondrial polymorphisms are homoplasmic. CCM followed by nucleotide sequencing of the corresponding region of the mitochondrial genome revealed a heteroplasmic mutation at nt 7512 in the tRNA(Ser(UCN)) gene. The 7512 (T to C) mutation disrupts a highly conserved base pair in the acceptor stem, and this mutation was not found in any of 120 normal controls, or in 43 patients with mitochondrial diseases. The proportion of the mutant mtDNA was 93% in muscle, 76 and 87% in the blood of the patients. A family member without apparent neuromuscular symptoms carried less mutant mtDNA. These findings support the view that this mutation is pathogenic in this family. Detection of heteroplasmy by CCM is an efficient means of screening pathogenic mtDNA point mutations.

Adult↗
PubMed1995

Midkine is present in the early stage of cerebral infarct.

Expression of midkine (MK), a growth factor with neurotrophic activities, was examined immunohistochemically in experimental cerebral infarct of rats. From postoperative day 1 to day 7 after the onset of infarct, anti-MK immunoreactivity was observed in the surrounding ischemic zone of the infarct but not in the necrotic lesion. The immunoreactive material was identified to be MK by Western blotting. On day 14, anti-MK immunoreactivity became negative. Absence of MK in the normal brain was verified both by immunohistochemical staining and Western blotting. The induced expression of MK is an early event: increased expression of glial fibrillary acidic protein (GFAP), a marker of astrocytes, started on day 4 and continued to day 14. These findings suggest that MK is produced around the site of nerve damage and plays a role as a reparative neurotrophic factor during the early phase of cerebral infarct.

Animals↗
PubMed1995

Sequencing of an 18.8 kb fragment from Saccharomyces cerevisiae chromosome VI.

The nucleotide sequence of lambda phage clone 4121, which contains the 18.8 kb fragment of Saccharomyces cerevisiae chromosome VI left arm, was determined. This sequence had seven open reading frames (ORFs), four of which were identical to known genes (ACT1, YPT1, TUB2 and RPO41). Another three ORFs (4121orfR003, 4121orfR004 and 4121orfRN001) were highly homologous to FET3 multi-copper oxidase, glucose transport protein, and hypothetical protein of YIL106w on chromosome IX, respectively. 4121orfRN01 is suggested to contain an intron.

Amino Acid Sequence↗
PubMed1995

Novel mutation at the initiation codon in the Norrie disease gene in two Japanese families.

We have identified a new mutation of Norrie disease (ND) gene in two Japanese males from unrelated families; they showed typical ocular features of ND but no mental retardation or hearing impairment. A mutation was found in both patients at the initiation codon of exon 2 of the ND gene (ATG to GTG), with otherwise normal nucleotide sequences. Their mothers had the normal and mutant types of the gene, which was expected for heterozygotes of the disease. The mutation of the initiation codon would cause the failure of ND gene expression or a defect in translation thereby truncating the amino terminus of ND protein. In view of the rarity and marked heterogeneity of mutations in the ND gene, the present apparently unrelated Japanese families who have lived in the same area for over two centuries presumably share the origin of the mutation.

Base Sequence↗
PubMed1995

A transgenic mouse line with alpha-1,3/4-fucosyl-transferase cDNA: production and characteristics.

cDNA of human alpha-1,3/4-fucosyltransferase (Fuc-TIII) was placed under the control of the chicken beta-actin promoter and cytomegalovirus enhancer, then introduced into male pronuclei of fertilized mouse eggs. A transgenic mouse line thus obtained exhibited enhanced expression of Lex (4C9) antigen in endothelial cells located in the glomerulus, sinusoidal capillaries of the liver and capillaries of the heart. Furthermore, in the transgenic mice, sialyl dimeric Lex (FH6) and sialyl Lea (2D3) antigens were strongly expressed in the glomerular endothelial cells.

Animals↗
PubMed1995

Relationship between morphological classification of the degree of maturation and the ploidy of micromegakaryocytes in myelodysplastic syndrome patients.

To clarify the biological behavior of micromegakaryocytes in myelodysplastic syndrome (MDS), the relationship between the morphological classification and the ploidy of megakaryocytes was studied in bone marrow aspirates obtained from patients with MDS and from normal controls. The morphology was determined according to Feinendegen's classification, which is considered to reflect megakaryocytic maturation, and the ploidy was determined by microcytofluorometry, using 4',6-diamidino-2-phenylindole (DAPI) staining after the removal of Wright-Giemsa stain. Most micromegakaryocytes (i.e., megakaryocytes < 20 microns in diameter) in MDS were morphologically mature, as were those in the normal controls. The peak micromegakaryocytic ploidy was 4N or 8N, whereas that of the megakaryocytes in normal controls was 16N. These findings indicated that the micromegakaryocytes in MDS were morphologically mature but had impaired polyploidization.

Adult↗
PubMed1995

The 8,344 mutation in mitochondrial DNA: a comparison between the proportion of mutant DNA and clinico-pathologic findings.

Ten patients, two men and eight women with mitochondrial encephalomyopathy, had an A-G mutation at nucleotide pair 8,344 in the mitochondrial DNA, the most common genetic defect in myoclonus epilepsy with ragged-red fibers (MERRF). Eight patients had the clinical and pathologic characteristics of MERRF including myoclonus, seizures, cerebellar ataxia and myopathy with ragged-red fibers. Two patients had atypical symptoms such as early onset of fatal cardiac failure and late onset of rapid mental deterioration, respectively. The striking feature in our patients with the 8,344 mutation cardiac involvement and two developed progressive heart failure. In the typical MERRF patients, the proportion of mutant mitochondrial DNA in their skeletal muscles, quantified by a single strand conformation polymorphism analysis, was above 85%. However, there was no significant correlation between clinical severity, histopathological findings and the proportion of mutant mtDNA in muscle biopsy samples, suggesting that non-ragged-red fibers play an important role in the phenotype expression of the mutants.

Adolescent↗
PubMed1995

Analysis of the nucleotide sequence of chromosome VI from Saccharomyces cerevisiae.

The complete nucleotide sequence of Saccharomyces cerevisiae chromosome VI (270 kb) has revealed that it contains 129 predicted or known genes (300 bp or longer). Thirty-seven (28%) of which have been identified previously. Among the 92 novel genes, 39 are highly homologous to previously identified genes. Local sequence motifs were compared to active ARS regions and inactive loci with perfect ARS core sequences to examine the relationship between these motifs and ARS activity. Additional ARS sequences were predominantly observed in 3' flanking sequences of active ARS loci.

Base Composition↗
PubMed1995

Lewis X structure increases cell substratum adhesion in L cells.

cDNAs of alpha-1,3-fucosyltransferase as well as alpha-1,3/4-fucosyltransferase were placed under the control of a beta-actin promoter and cytomegalovirus enhancer and were introduced into L cells. The transfected cells expressing Le(x) antigen showed increased cell substratum adhesion as compared to the antigen-negative cells, when they were cultured for 2 to 4 h in Dulbecco-modified minimum essential medium containing 0.05% bovine serum albumin. The increased cell substratum adhesion was completely inhibited by cycloheximide and anti-integrin antiserum, and partly by an RGD peptide and EGTA. These findings indicate that Le(x) structure promotes cell adhesion to substratum-bound material secreted by cells, and that the increased adhesion is mediated by integrin. Western blotting experiments have revealed an 85 kDa protein and a 50-60 kDa protein as carriers of Le(x) antigen in transfected cells. The latter is likely to be basigin, which is a member of the immunoglobulin superfamily and is considered to be an integrin-associated protein. We hypothesize that fucosylation of basigin enhances integrin-mediated cell substratum adhesion.

Animals↗
PubMed1995

The fourth armadillo repeat of plakoglobin (gamma-catenin) is required for its high affinity binding to the cytoplasmic domains of E-cadherin and desmosomal cadherin Dsg2, and the tumor suppressor APC protein.

Plakoglobin is a member of a protein family with a repeated amino acid motif, the armadillo repeat, and is a cytoplasmic protein found in both adherens junctions and desmosomes. Plakoglobin has been shown to form distinct complexes with cadherins or desmosomal cadherins. Also, plakoglobin has been shown to complex with APC, the tumor suppressor gene product. Recently we isolated a cDNA clone encoding plakoglobin lacking the fourth armadillo repeat of the original 13-repeat protein [Ozawa et al. (1995) J. Biochem. 118, 836-840]. In this study, we established an in vitro assay system to study the molecular interaction of plakoglobin with cadherins, the APC gene product, and alpha-catenin. Establishment of the system and cloning of an alternate form of plakoglobin cDNA allowed us to examine the biological activity of plakoglobin lacking the fourth armadillo repeat. Experiments with the bacterially expressed 12-repeat plakoglobin revealed that the protein binds to E-cadherin, desmoglein (Dsg2), and APC with lower affinity than the 13-repeat form does. Consistent with the observation that the affinity of alpha-catenin for these two alternate forms was similar, we found amino acid residues 104 to 145 of plakoglobin, the residues present in both isoforms, are sufficient for its binding to alpha-catenin.

Adenomatous Polyposis Coli Protein↗
PubMed1995

Cloning of a human homologue of mouse reticulocalbin reveals conservation of structural domains in the novel endoplasmic reticulum resident Ca(2+)-binding protein with multiple EF-hand motifs.

Recently, we described the isolation of a mouse cDNA clone encoding a novel Ca(2+)-binding protein, tentatively designated as reticulocalbin [Ozawa, M. and Muramatsu, T. (1993) J. Biol. Chem. 268, 699-705]. Reticulocalbin is a lumenal protein of the endoplasmic reticulum (ER) with a molecular weight of 44,000 and has six repeats of a domain containing the high affinity EF-hand Ca(2+)-binding motif. The protein has the sequence, His-Asp-Glu-Leu (HDEL), at its carboxy terminus, which serves as a signal for its retention in the ER of cells. To examine the importance of the putative Ca(2+)-binding domains as well as the carboxy-terminal HDEL sequence, we have cloned the human homologue of reticulocalbin. The sequence of this clone revealed a novel protein with 95% identity in amino acid sequence to the mouse reticulocalbin, indicating that this molecule has been evolutionarily conserved in mammals. As was found for the mouse reticulocalbin, the human homologue showed six repeats of a domain containing EF-hand motifs. Interestingly, conservation of the amino acid sequence was not restricted to the Ca(2+)-binding motifs, consistent with the possibility that reticulocalbin plays some role(s) besides Ca(2+)-binding. As was found for the mouse homologue, the protein has the HDEL sequence at its carboxy terminus instead of the Lys-Asp-Glu-Leu (KDEL) sequence, which is more common as a signal for the retention of resident proteins in the ER of animal cells. The conservation of the HDEL sequence in reticulocalbin in both species raises the possibility that this sequence has some roles in the function(s) of this protein family.

Amino Acid Sequence↗