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Biomedical subjects

N Miyamoto

Publications and source records attributed to N Miyamoto.

At least 19 recordsLinked to original sources
PubMed1998

Rainbow trout Sox24, a novel member of the Sox family, is a transcriptional regulator during oogenesis.

We isolated a cDNA clone encoding a novel SRY-type HMG box (Sox) protein, designated Sox24, from a rainbow trout ovary cDNA library. On the basis of the HMG box amino acid sequence, Sox24 can be categorized into the same subgroup of Sox proteins as SOX4, SOX11, and SOX22. The proteins in this group also share a highly conserved sequence at the C-terminus. The Sox24 mRNA is expressed at high levels in the ovary, and in-situ hybridization localized its expression to oocytes. The recombinant protein containing the Sox24 HMG box region bound to an AACAAT sequence strongly in a gel retardation assay. Upon co-transfection into CHO cells, the full-length Sox24 transactivated transcription from a reporter plasmid through the AACAAT binding motif. We used GAL4/Sox24 chimeras with the DNA binding domain of yeast GAL4 at the N-terminus to map the transactivation function to the C-terminal region, which included the conserved sequence. These results suggest that Sox24 plays a role as a transcriptional regulator during oogenesis.

Amino Acid Sequence↗
PubMed1998

Transient increase in CD45RO expression on T lymphocytes in infected newborns.

Although infections are a significant cause of mortality and long-term morbidity of newborns, the early diagnosis of neonatal infections remains difficult. It has been shown recently that up-regulation of CD45RO expression on umbilical cord lymphocytes might be a good indicator for intrauterine viral infections. To evaluate clinical relevance of changes in CD45 isoforms to the diagnosis of neonatal infections, we examined CD45RA and CD45RO expression on total, CD4+, and CD8+ lymphocytes from newborns. Lymphocytes from 55 newborns who were hospitalized in Kiyose Metropolitan Children's Hospital or Yamanashi Medical University Hospital were analyzed. Newborns were classified into three groups according to the possibility of bacterial or viral infection; I ("no" infection, n = 24), II ("possible" infection, n = 17), and III ("definite" infection, n = 14). Results were compared between two of three groups. The CD45RO expression on total or CD4+ lymphocytes in group III (bacterial 12, viral 2) was significantly higher than that in group I or II. Particularly, the CD45RO expression on CD4+ lymphocytes was always greater than 10% in group III, and showed no overlap with the respective value in group I. After termination of infection, the increased CD45RO expression in group III gradually returned to normal levels. These results indicate that not only viral but also bacterial infections trigger transient and reversible changes in CD45 isoform expression by neonatal CD4+ T lymphocytes. This may be a novel marker for the early diagnosis of neonatal infections.

CD3 Complex↗
PubMed1998

Magnetic resonance imaging of Bland-White-Garland syndrome--a case of anomalous origin of the left coronary artery from the pulmonary trunk in a 22-year-old woman.

Selective right coronary angiography in a 22-year-old woman demonstrated an enormous right coronary artery, with the contrast medium opacifying to the left coronary artery through a well-developed collateral circulation and draining into the pulmonary artery. The diagnosis of anomalous origin of the left coronary artery from the pulmonary trunk [also known as Bland-White-Garland (BWG) syndrome] was thus established. Magnetic resonance imaging (MRI) showed a dilated right coronary artery arising from the aorta, the left coronary artery from the pulmonary trunk but not from the aorta, and well-developed channels in the interventricular septum. MRI could be a useful tool for diagnosing anomalous origin of the left coronary artery from the pulmonary trunk.

Coronary Vessel Anomalies↗
PubMed1997

Kinetics of the ascension of NTHi from the nasopharynx to the middle ear coincident with adenovirus-induced compromise in the chinchilla.

To determine the kinetics of ascension of the eustachian tube (ET) by non-typeable Haemophilus influenzae (NTHi) in situ from the nasopharynx to the middle ear using an experimental model of otitis media (OM), we examined snap-frozen sections of chinchilla ET and middle ear mucosa for adherent bacteria over a 14 day time period. Via fluorescent- and transmission electron-microscopy, we found that NTHi preferentially adhered not to the epithelial cells but to the mucus in the ET and gradually ascended this tubal organ, reaching the middle ear approximately 10 days after intranasal inoculation of adenovirus-infected animals. The number of NTHi adherent to mucus at the pharyngeal portion of the ET increased significantly in the first 4 days after inoculation of the nares whereas the number of adherent bacteria in both the mid and tympanic portions of the ET increased more gradually over time. NTHi were not observed in the middle ear until approximately 7-10 days after inoculation of the nares which was coincident with the onset of clinical signs of OM. These data confirmed our earlier in vitro investigation which suggested that adherence to and growth within stagnant mucus within a ET compromised by adenovirus was a possible mechanism by which NTHi, resident in the nasopharynx, might gain access to the middle ear and induce OM.

Acoustic Impedance Tests↗
PubMed1997

Changes in the expression of adenylyl cyclases in the rat uterus during the course of pregnancy.

The changes in the expression of the various adenylyl cyclases (ACs) in the rat uterus during the course of pregnancy and after delivery were examined by Northern blot analysis and AC assay. Northern blot analysis revealed that five isoforms of ACs (AC2, AC4, AC6, AC7, and AC9) were expressed in the rat uterus, AC6 being the most abundant. The level of expression of these ACs increased 1.7- to 3.4-fold during the course of pregnancy and diminished near term and after delivery. The highest level of expression in each type of AC was consistently seen on Day 17 of pregnancy, and the relative increase of expression, as compared to that in nonpregnant rats, was as follows: AC2 > AC4 > AC7 > AC9 > AC6. In agreement with these findings, both basal and forskolin-stimulated AC activities exhibited a 2- to 3-fold increase during the course of pregnancy, followed by a decrease near term. Our data indicate that post-receptor events, namely marked changes in the level of AC mRNA (and presumably proteins) occur during pregnancy and after delivery and that they contribute to the essential role of cAMP in maintaining uterus quiescence.

Adenylyl Cyclases↗
PubMed1997

Expression of adenylyl cyclase mRNAs in the adult, in developing, and in the Brattleboro rat kidney.

The activity and expression of adenylyl cyclases (AC) were examined in the adult rat renal cortex and medulla. Northern blot analysis and in situ hybridization demonstrated that AC-6 was the predominant isoform in the adult rat kidney, whereas AC-4, -5, and -9 had a lower expression. AC-4 expression was higher in the cortex, and AC-5 and AC-6 were higher in the medulla. AC-9 expression was at the same level in both regions. AC activity was high in the fetus and declined in the adult. At all stages, AC activity was sensitive to parathyroid hormone, whereas no stimulation by vasopressin and isoproterenol was found in the fetus and the neonate. AC-5 and AC-6 mRNAs increased at day 1 and then markedly decreased, paralleling the decline in AC activity. The mRNA of AC-4 did not change and that of AC-9 increased markedly until adult. In the homozygous Brattleboro rat kidney, the expression of all these isoforms was decreased.

Adenylyl Cyclases↗
PubMed1997

Emx1 and Emx2 functions in development of dorsal telencephalon.

The genes Emx1 and Emx2 are mouse cognates of a Drosophila head gap gene, empty spiracles, and their expression patterns have suggested their involvement in regional patterning of the forebrain. To define their functions we introduced mutations into these loci. The newborn Emx2 mutants displayed defects in archipallium structures that are believed to play essential roles in learning, memory and behavior: the dentate gyrus was missing, and the hippocampus and medial limbic cortex were greatly reduced in size. In contrast, defects were subtle in adult Emx1 mutant brain. In the early developing Emx2 mutant forebrain, the evagination of cerebral hemispheres was reduced and the roof between the hemispheres was expanded, suggesting the lateral shift of its boundary. Defects were not apparent, however, in the region where Emx1 expression overlaps that of Emx2, nor was any defect found in the early embryonic forebrain caused by mutation of the Emx1 gene, of which expression principally occurs within the Emx2-positive region. Emx2 most likely delineates the palliochoroidal boundary in the absence of Emx1 expression during early dorsal forebrain patterning. In the more lateral region of telencephalon, Emx2-deficiency may be compensated for by Emx1 and vice versa. Phenotypes of newborn brains also suggest that these genes function in neurogenesis corresponding to their later expressions.

Animals↗
PubMed1997

Defects of urogenital development in mice lacking Emx2.

The homeobox gene Emx2 is a mouse homologue of a Drosophila head gap gene empty spiracles (ems) and is essential for the development of dorsal telencephalon (Yoshida, M., Suda, Y., Matsuo, I., Miyamoto, N., Takeda, N., Kuratani, S. and Aizawa, S. (1997) Development 124, 101-111). At the same time, Emx2 is expressed in the epithelial components of the developing urogenital system and, in Emx2 mutant mice, the kidneys, ureters, gonads and genital tracts were completely missing. Pax-2 and c-ret expressions in the Wolffian duct and WT-1 and GDNF expressions in the metanephric blastema were initially normal in the mutant. The ureteric bud grew and invaded the metanephric mesenchyme where Pax-2 expression was normally induced. Subsequently, however, Pax-2, c-ret and Lim1 expressions in the ureteric bud and GDNF expression in the mesenchyme were greatly reduced. Wnt-4 expression was never found in the mesenchyme. The tip of the ureteric bud never dilated and branching of the bud did not occur. Neither pretubular cell aggregates nor epithelialization were found in the mesenchyme. Instead the ureteric bud soon degenerated and apoptotic figures were prominent in mesenchymal cells. In explant culture, the mutant ureteric bud did not induce the epithelial transformation of the wild-type mesenchyme, and branching of the mutant ureteric bud was not induced by wild-type mesenchyme. In contrast, defects were not apparent in the mutant mesenchyme by co-culture with wild-type ureteric bud or spinal cord. These results suggest that, in metanephrogenesis, Emx2 is essential for the ureteric bud functions subsequent to Pax-2 induction in the metanephric mesenchyme. Degeneration of the Wolffian duct and mesonephric tubules was also abnormally accelerated without the formation of the Mullerian duct.

Animals↗
PubMed1997

[Pulmonary arterial reconstruction with autologous pulmonary arterial tissue for pulmonary artery sling].

One-year and two-month-old boy with pulmonary artery sling underwent pulmonary artery reconstruction with autologous pulmonary arterial tissue. Surgical repair consisted of the transection of the left pulmonary artery at its origin with trimming a button hole and the creation of an oval hole with the same size to the left pulmonary button. An autologous pulmonary patch and the left pulmonary button were exchanged and sutured to the former partner's place. He recovered uneventfully in post-operative course. Postoperative CT revealed a well developed left pulmonary artery from 5 mm to 10 mm in diameter without any distortion or stenosis. This exchange method could allow the natural growth of the anastomotic places without narrowing or distortion.

Anastomosis, Surgical↗
PubMed1997

[Surgical treatment of thoracic aorta for elderly patient].

From 1986 to 1996, 237 patients underwent surgical treatment of thoracic aorta in our institute. We classified them as follows: group 1 is 41 patients older than 75: group 2 is 196 patients younger than 74. The number of patients of elective surgery, emergent surgery for acute dissection type A and emergent surgery for rupture or impending rupture were 28, 9, 4 in group 1 and 123, 47, 26 in group 2. Operative death (within 30 days) of elective surgery, emergent surgery for acute dissection type A and emergent surgery for rupture or impending rupture were 1 (3.6%, MOF), 1 (11%, liver failure), 2 (50%, brain damage) in group 1 and 8 (6.5), 3 (6.4%), 9 (35%) in group 2, respectively. Hospital deaths (after 30 days and cannot discharge) were 3 (11%), 0.1 (25%) in group 1 and 3 (2.4%), 1 (2.1%), 1 (3.8%) in group 2. There was no significant difference between two groups. Survival rate of each group were 48% and 80% for five-year survival rate. Complications in elderly patients were common (88%). Respiratory insufficiency is the most frequent (51%). Otherwise survival rate of patients who had no surgical treatment of diseased thoracic aorta was reported poor by several researches. We will perform operation for elderly patients positively if we can get agreement of patients.

Acute Disease↗
PubMed1997

[Cord blood stem cell transplantation for infantile acute lymphoblastic leukemia after primary cytomegalovirus infection].

We report a 1-year-old boy with infantile lymphoblastic leukemia in first complete remission who received a cord blood stem cell transplantation (CBSCT) from an HLA identical sibling. We collected 120 ml of cord blood when his brother was born, which contained 4.2 x 10(8) mononuclear cells (4.2 x 10(7)/kg) and 3.1 x 10(5) CFU-GM (3.1 x 10(4)/kg). One month prior to transplantation, he showed persistent fever and liver dysfunction, and was finally diagnosed as having primary cytomegalovirus (CMV) infection which was demonstrated by elevation of serum anti-CMV-IgM. The administration of ganciclovir dramatically improved the clinical symptoms and abnormal laboratory findings, and was continued up to 1 month after transplantation to suppress the CMV reactivation. The preconditioning regimen consisted of busulfan (16 mg/kg/4 days) and cyclophosphamide (120 mg/kg/2 days), and cyclosporin A (CyA) alone was used for graft-versus-host disease (GVHD) prophylaxis. Fever suspicious of grade I GVHD developed on day 19, but subsided by increasing the dose of CyA. The WBC and platelet counts reached greater than 1,000/microliter and 50 x 10(3)/microliter on days 12 and 42, respectively. It is now at 13 months since transplantation, and he remains in a disease free state.

Antiviral Agents↗
PubMed1996

Selective adherence of non-typeable Haemophilus influenzae (NTHi) to mucus or epithelial cells in the chinchilla eustachian tube and middle ear.

Frozen sections of chinchilla Eustachian tube (ET) and middle ear mucosa were incubated with either FITC-labeled non-typeable Haemophilus influenzae (NTHi) or Bordetella pertussis. The number of bacteria adherent to "roof" vs "floor" regions was compared for each of three anatomic portions of the ET and for middle ear epithelium noting whether bacteria adhered to mucus or to epithelial cells. NTHi strains adhered significantly greater to mucus in the ET lumen whereas B. pertussis preferentially adhered to epithelial cells lining the ET (P < or = 0.05). A non-fimbriated isogenic mutant of NTHi adhered significantly less to mucus than the parental isolate at all sites of the ET floor (P < or = 0.05). Isolated fimbrin protein adhered to ET mucus and blocked adherence of whole organisms. Treatment with the mucolytic agent N-acetyl-L-cysteine resulted in significantly reduced adherence of NTHi to mucus (P < or = 0.001) and eliminated the ability to detect binding of isolated fimbrin protein. N-acetyl-L-cysteine treatment did not affect adherence of either B. pertussis or NTHi to epithelial cells. These data indicated that NTHi may mediate ascension of the ET from the nasopharynx primarily via adherence to and growth in mucus overlying the floor region of the tubal lumen. The OMP P5-homologous fimbriae were shown to contribute to this binding.

Acetylcysteine↗