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Biomedical subjects

T Hatta

Publications and source records attributed to T Hatta.

At least 37 records · Page 2Linked to original sources
PubMed2000

Mouse Ror2 receptor tyrosine kinase is required for the heart development and limb formation.

BACKGROUND: A mouse receptor tyrosine kinase (RTK), mRor2, which belongs to the Ror-family of RTKs consisting of at least two structurally related members, is primarily expressed in the heart and nervous system during mouse development. To elucidate the function of mRor2, we generated mice with a mutated mRor2 locus. RESULTS: Mice with a homozygous mutation in mRor2 died just after birth, exhibiting dwarfism, severe cyanosis, and short limbs and tails. Whole-mount in situ hybridization analysis showed that mRor2 was expressed in the branchial arches, heart and limb/tailbuds, in addition to the developing nervous system. The mutants had cardiac septal defects, mainly a ventricular septal defect. In addition, an examination of the skeletal systems revealed that the mutants had shorter limbs, vertebrae and facial structure, with a particular defect in their distal portions, and that almost no calcification was observed in their distal limbs. Histological examination showed abnormalities in the chondrocytes. CONCLUSIONS: Our findings suggest that mRor2 plays essential roles in the development of the heart and in limb/tail formation, in particular cardiac septal formation and ossification of distal portions of limbs and tails.

Animals↗
PubMed2000

Fluorescence microscopic visualization of a DNA-cationic fullerene complex.

Cationic fullerene derivative 1, which is soluble in aqueous medium, bound to double stranded DNA. Observation of Coliphage T4 DNA in the absence and presence of 1 by fluorescence microscopy suggested that 1 bound to DNA along its groove. Upon irradiation of visible light on the DNA complex of 1, DNA was cleaved dramatically. The process of DNA photo-cleavage could be monitored continuously by fluorescence microscopy.

Bacteriophage T4↗
PubMed2000

Implications of the symbol figure representations: information from the direction and spatial location used by Japanese students.

Meanings of physical distance, spatial location, and direction of symbolic figure in the Doll Location Test were investigated with 283 normal college students in Japan. They were asked to indicate eight symbolic figures of hypothetical people such as reliable father, unreliable mother on a recording sheet. The physical dyadic distance from the self, spatial location, and direction of symbolic figures were analyzed. Positive persons were placed twice as close as a negative person. Analysis of direction showed that more than 90% of the positive people were represented in either the same direction as or facing self, whereas a negative person was represented either in the opposite or in an unrelated direction from the self. Spatial location of the symbolic figures did not yield evaluative values.

Adult↗
PubMed2000

How Japanese students characterize information from web-sites.

How 352 Japanese university students regard web-site information was investigated by two kinds of survey. Application of correspondence analysis and cluster analysis to the questionnaire responses to the web-site advertisement showed students regarded a web-site as a new alien medium which is different from current media. Students regarded web-sites as simply complicated, intellectual, and impermanent, or not memorable. Students got precise information from web-sites but they did not use it in making decisions to purchase goods.

Adolescent↗
PubMed2000

Interpersonal constructs of pregnant married women during pregnancy and postpartum period as perceptions of family members.

Interpersonal constructs and their dynamics in pregnant women during the perinatal period were investigated using a symbol figure placement technique and a semantic differential test. 16 pregnant women represented their interpersonal perceptions of family members (husband, mother, father, mother-in-law, father-in-law, and child) at four different times (34 weeks of pregnancy, 37 weeks of pregnancy, and 3 days and 30 days after delivery). Two tests indicated positive perceptions of the pregnant women (cohesion, confidence, and dependence) of family members changed over the perinatal period and their interpersonal perceptions of self-husband and self-child were the most positive next to self-mother. Based upon these findings, the support system for pregnant women was discussed.

Adult↗
PubMed1999

PcpA, which is involved in the degradation of pentachlorophenol in Sphingomonas chlorophenolica ATCC39723, is a novel type of ring-cleavage dioxygenase.

The pentachlorophenol (PCP) mineralizing bacterium Sphingomonas chlorophenolica ATCC39723 degrades PCP via 2,6-dichlorohydroquinone (2,6-DCHQ). The pathway converting PCP to 2,6-DCHQ has been established previously; however, the pathway beyond 2,6-DCHQ is not clear, although it has been suggested that a PcpA plays a role in 2, 6-DCHQ conversion. In this study, PcpA expressed in Escherichia coli was purified to homogeneity and shown to have novel ring-cleavage dioxygenase activity in conjunction with hydroquinone derivatives, and converting 2,6-DCHQ to 2-chloromaleylacetate.

Amino Acid Sequence↗
PubMed1999

Isolation and characterization of a thermophilic Bacillus sp. JF8 capable of degrading polychlorinated biphenyls and naphthalene.

Bacillus sp. strain JF8, which was isolated from compost, utilizes naphthalene and biphenyl as carbon sources at 60 degrees C. Biphenyl grown cells of strain JF8 barely degraded naphthalene while naphthalene grown cells did not degrade p-chlorobiphenyl, suggesting the existince of two independent degradation pathways. Isolation of JF8N, a mutant strain which can not utilize biphenyl as a carbon source while retaining the ability to utilize naphthalene, supports this hypothesis. Biphenyl grown cells of strain JF8 can degrade several polychlorinated biphenyl congeners including tetra- and pentachlorobiphenyl. bph and nah probes from mesophilic organisms failed to hybridize to strain JF8 DNA.

Bacillus↗
PubMed1999

Traumatic cardiac herniation diagnosed by echocardiography and chest CT scanning: report of a case.

A 62-year-old man who had suffered fractures of the left chest wall and hemothorax 1 year earlier was admitted to our hospital with multiple injuries as a result of a traffic accident. Chest drainage was immediately performed under the diagnosis of left hemothorax followed by immobilization of fractures of the femur and radius. On the second day after admission, he suddenly developed severe chest pain and dyspnea after sitting up in bed. Echocardiography and chest computed tomography (CT) showed herniation of the left ventricle into the left thoracic cavity, whereby a diagnosis of cardiac herniation due to rupture of the pericardium was made and an emergency surgical repair was successfully performed. Only eight cases of patients surviving after traumatic cardiac herniation have been reported in Japan; however, this is the first in which a preoperative diagnosis was made by echocardiography and chest CT scanning prior to surgical repair.

Accidents, Traffic↗
PubMed1999

Apoptosis during inner ear development in human and mouse embryos: an analysis by computer-assisted three-dimensional reconstruction.

Apoptosis in the developing inner ear tissue of human (Carnegie stage 14 to 21, approximately 5 to 8 weeks of gestation) and mouse (10.5 to 14 days of gestation) embryos was systematically analyzed by a computer-assisted three-dimensional reconstruction of the serial histological sections and by the TUNEL method. Morphogenetic events such as folding between the utricular portion and endolymphatic duct, constriction of the junction of the saccule with the cochlea and folding of the vestibular portion to form the semicircular ducts were accompanied by a localized distribution of apoptosis. The apoptosis was also related to the innervation of the cochlear and vestibular epithelia from the sensory ganglion of the eighth cranial nerve and the differentiation of the otic epithelia into the sensory epithelia. These results suggest that apoptosis plays an important role in the development of the inner ear.

Animals↗
PubMed1999

Cloning and sequence analysis of hydroxyquinol 1,2-dioxygenase gene in 2,4,6-trichlorophenol-degrading Ralstonia pickettii DTP0602 and characterization of its product.

A gene encoding hydroxyquinol 1,2-dioxygenase was cloned from 2,4,6-trichlorophenol-degrading Ralstonia (Pseudomonas) pickettii strain DTP0602. Cell-free extracts of Escherichia coli containing a cloned 1.4-kb StuI-XhoI DNA fragment of R. pickettii DTP0602 hydroxyquinol 1,2-dioxygenase converted hydroxyquinol into maleylacetate and also degraded 6-chlorohydroxyquinol. The 1.4-kb DNA fragment contained one open reading frame (designated hadC) composed of 948 nucleotides. The molecular mass of 34,591 deduced from the gene product (HadC) was in agreement with the size (35 kDa) of the purified HadC protein determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The amino acid sequence of HadC exhibited high homology to that of the hydroxyquinol 1,2-dioxygenase of 2,4,5-trichlorophenoxyacetic acid-degrading Burkholderia cepacia AC1100 (Daubaras, D. L. et al., Appl. Environ. Microbiol., 61, 1279-1289, 1995). The active enzyme had a molecular mass of 68 kDa, suggesting that it is functional as a homodimer. The enzyme also catalyzed the oxidation of pyrogallol and 3-methylcatechol, possible intermediates in the degradation of 2,4,6-trichlorophenol, in addition to 6-chlorohydroxyquinol and hydroxyquinol. The dioxygenase catalyzed both ortho- and meta-cleavage of 3-methylcatechol.

Journal Article↗
PubMed1999

Antisense oligonucleotides directed against the viral RNA polymerase gene enhance survival of mice infected with influenza A.

We have investigated the ability of antisense phosphorothioate oligonucleotides to enhance the survival of mice infected with influenza A virus. The oligonucleotides were complementary to sequences surrounding the translation initiation codons of the viral PB2 or PA genes (PB2-as or PA-as, respectively) of the influenza A virus RNA polymerases. Intravenous administration of PB2-as in a complex with a cationic liposome, Tfx-10, significantly prolonged the mean survival time in days and increased overall survival rates of mice infected with the influenza A virus. Liposomally encapsulated PB2-as inhibited viral growth in lung tissues and reduced pulmonary consolidations. Liposomally encapsulated PB2-as could be an effective therapeutic agent against influenza A virus.

Animals↗
PubMed1999

Spatio-temporally regulated expression of receptor tyrosine kinases, mRor1, mRor2, during mouse development: implications in development and function of the nervous system.

BACKGROUND: Drosophila neurospecific receptor tyrosine kinases (RTKs), Dror and Dnrk, as well as Ror1 and Ror2 RTKs, isolated from human neuroblastoma, have been identified as a structurally related novel family of RTKs (Ror-family RTKs). Thus far, little is known about the expression and function of mammalian Ror-family RTKs. RESULTS: We have identified murine Ror-family RTKs, mRor1 and mRor2. Both mRor1 and mRor2 genes are induced upon neuronal differentiation of P19EC cells. During neuronal differentiation in vitro, the expression of mRor2 is transiently induced, although that of mRor1 increases continuously. During embryogenesis, the mRor1 gene is expressed in the developing nervous system within restricted regions and in the developing lens epithelium. The expression of mRor1 is sustained in the nervous system and is also detected in non-neuronal tissues after birth. In contrast, the expression of mRor2 is detected mainly in the developing nervous system within broader regions and declines after birth. Possible relationships of mRor1 and mRor2 genes with previously identified mutants have also been examined. CONCLUSIONS: The developmental expressions of mRor1 and mRor2, in particular in the nervous system, are differentially regulated, reflecting their expression patterns in vitro. mRor1 and mRor2 may thus play differential roles during the development of the nervous system.

Amino Acid Sequence↗
PubMed1999

Developmental neurotoxicity of phenytoin on granule cells and Purkinje cells in mouse cerebellum.

Phenytoin (PHT) is a primary antiepileptic drug. Cerebellar malformations in human neonates have been described following intrauterine exposure to PHT. The neonatal period of development in the cerebellum in mice corresponds to the last trimester in humans. To examine the neurotoxic effects of PHT in the developing cerebellum, we administered PHT orally to newborn mice once a day during postnatal days 2-4. We observed many apoptotic cells in the external granular layer (EGL) on postnatal day 5, labeled cells in the EGL still remaining 72 h after labeling with 5-bromo-2'-deoxyuridine, and EGL thicker than that in the control on postnatal day 14. These results showed that PHT induced cell death of external granule cells and inhibited migration of granule cells in cerebella. In specimens immunostained with antibody against inositol 1,4,5-trisphosphate receptor type 1, Purkinje cells in the treated group had poor and immature arbors, and partially showed an irregular arrangement. The motor performance of the treated mice in a rotating rod test was impaired, although there were no changes in muscular strength or in walking pattern at the period of maturity. These findings indicate that PHT induces neurotoxic damage to granule cells and Purkinje cells in the developing cerebellum and impairs selected aspects of motor coordination ability.

Animals↗
PubMed1999

Acute in vivo effects of ACTH by exo utero microinjection on differentiation, steroidogenesis and proliferation of fetal mouse adrenocytes.

Mouse embryos on embryonic day (E)13 or 14 were treated with ACTH1-24 by exo utero microinjection and the adrenal was examined after 16 and 32 h. Light microscopic morphometry showed that the ACTH treatment increased cell size and decreased cell density of the adrenocortical cells. Bromodeoxyuridine-labeling index did not alter significantly after the ACTH treatment. By immunohistochemistry, both number of cells expressing 11beta-hydroxylase and the staining intensity increased in the ACTH-treated glands compared to controls whereas expression of aldosterone synthase was detectable in neither the treated nor control groups. Ultrastructurally, the adrenocytes of the inner cortical zone of the ACTH-treated glands were characterized by strikingly increased content of the smooth endoplasmic reticulum, increased mitochondria with more vesicular cristae, lipid droplets with a much higher electron density along with the distribution altered from that in controls. All of the significant differences between the ACTH-treated and control glands occurred at 16 h but not at the 32 h interval. The present results indicated that the mouse fetal adrenocytes are already sensitive to ACTH during early period (E13 and 14) of their functional differentiation. In vivo acute treatment of ACTH stimulates cell-size, increase of fetal adrenocytes but not proliferation, and may directly or indirectly regulate multiple steps of the steroidogenic process of the fetal mouse adrenal.

Adrenal Cortex↗
PubMed1999

Hemisphere specialisation and categorical spatial relations representations.

Hemisphere specialisation in two- and three-dimensional categorical spatial relations tasks was investigated using normal adult subjects. In Experiment 1, subjects were asked to indicate the rightmost (or leftmost) card in stimuli consisting of three overlapping cards as quickly and as accurately as possible. The results showed no significant visual field difference in either response times or error rates. In Experiment 2, stimuli identical to those of Experiment 1 were used and subjects were asked to indicate the card most to the front or the one most to the back. The error rates showed a strong tendency towards a left visual field advantage in accuracy while no visual field difference was shown in response times. Based on these findings, relations between the hemisphere specialisation and categorical spatial relations encoding subsystems in Kosslyn's (1987) model of visual information processing are discussed.

Journal Article↗
PubMed1999

DNA coated with cationic fullerene derivative. A possible microwire in water.

Fullerene derivative 2 carrying pyridinium cation bound to sonicated calf thymus DNA in water. The binding ratio was 1 fullerene unit to 1 phosphate residue, giving the complex where DNA strand is seemingly coated with electron-conducting fullerenes. Cyclic voltammetry shows three-step redox couples in the complex, and the current peaks were broadened and shifted to positive side as compared to uncomplexed 2. Binding of 2 onto grooves of DNA double helix was suggested.

Carbon↗
PubMed1999

Myogenic determination and differentiation of the mouse palatal muscle in relation to the developing mandibular nerve.

The vertebrate palatal muscles are derived from the cranial paraxial mesoderm and start myogenesis by the expression of myogenic regulatory factors (MRFs). Predetermined myogenic cells migrate from the cranial paraxial mesoderm into the branchial arches, followed by myogenic differentiation. The objective of this study was to elucidate whether the determination, migration, and differentiation of myogenic cells during the myogenesis of the palatal muscles, particularly the tensor veli palatini (TVP), are related to the extending mandibular nerve in mouse embryos. By immunohistochemical staining at embryonic day (E) 9.5, MyoD1 and myogenin have been expressed in the mandibular arch, into which the mandibular nerve had not yet extended. At E11.5, these myogenic cells encircled the extending mandibular nerve and were distributed from the distal and lateral to the trigeminal ganglion and into the mandibular arch to form the muscle plate, a girdle-like structure. By E12.5, these myogenic cells lost their girdle-like pattern, vacated the trunk area of the mandibular nerve, and were separated into several incompletely divided masses encircling the collateral branches of the mandibular nerve. The TVP started differentiation at E13.5 with the appearance of myofilaments and acetylcholinesterase (AchE), whereas the other palatal muscles began differentiation at E14.5. We defined the differentiation process of mouse palatal muscles into five stages based on the present findings. These results suggest that the determination and initial migration of the palatal myogenic cells into the mandibular arch occur before the mandibular nerve extends out of the trigeminal ganglion, whereas the myogenic cells migrating into the final sites of differentiation intimately relate to the extending nerve.

Acetylcholinesterase↗