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T Mito

Publications and source records attributed to T Mito.

At least 19 recordsLinked to original sources
PubMed2006

The characteristics of karyotype and telomeric satellite DNA sequences in the cricket, Gryllus bimaculatus (Orthoptera, Gryllidae).

The chromosomes derived from the Japanese population of Gryllus bimaculatus were characterized by C-banding and Ag-NOR staining. The chromosome number, 2n = 28 + XX (female)/XO (male), corresponded with that of other populations of G. bimaculatus, but the chromosome configuration in idiograms varied between the populations. NORs were carried on one pair of autosomes and appeared polymorphous. The positive C-bands located at the centromere of all chromosomes and the distal regions of many chromosome pairs, and the size and the distribution pattern of the distal C-heterochromatin showed differences among the chromosomes. In addition, this paper reports on the characteristics of HindIII satellite DNA isolated from the genome of G. bimaculatus. The HindIII repetitive fragments were about 0.54 kb long, and localized at the distal C-bands of the autosomes and the interstitial C-bands of the X chromosome. Molecular analysis showed two distinct satellite DNA sequences, named the GBH535 and GBH542 families, with high AT contents of about 67 and 66%, respectively. The two repetitive families seem to be derived from a common ancestral sequence, and both families possessed the same 13-bp palindrome sequence. The results of Southern blot hybridization suggest that the sequence of the GBH535 family is conserved in the genomic DNAs of Gryllus species, whereas the GBH542 family is a species-specific sequence.

Animals↗
PubMed2003

Gapless magnetic and quasiparticle excitations due to the coexistence of antiferromagnetism and superconductivity in CeRhIn5: a study of 115In NQR under pressure.

We report systematic measurements of ac susceptibility, nuclear-quadrupole-resonance spectrum, and nuclear-spin-lattice-relaxation time (T1) on the pressure (P)-induced heavy-fermion superconductor CeRhIn5. The temperature (T) dependence of 1/T(1) at P=1.6 GPa has revealed that antiferromagnetism (AFM) and superconductivity (SC) coexist microscopically, exhibiting the respective transition at T(N)=2.8 K and T(MF)(c)=0.9 K. It is demonstrated that SC does not yield any trace of gap opening in low-lying excitations below T(onset)(c)=2 K, but T(MF)(c)=0.9 K, followed by a T(1)T=const law. These results point to the unconventional characteristics of SC coexisting with AFM. We highlight that both of the results deserve theoretical work on the gapless nature in the low-lying excitation spectrum due to the coexistence of AFM and SC and the lack of the mean-field regime below T(onset)(c)=2 K.

Journal Article↗
PubMed2003

Sawtooth oscillation in current-carrying plasma in the large helical device.

Sawtooth oscillations have been observed in current-carrying helical plasmas by using electron-cyclotron-emission diagnostics in the Large Helical Device. The plasma current, which is driven by neutral beam injection, reduces the beta threshold of the sawtooth oscillation. When the central q value is increased due to the plasma current, the core region crashes, and, when it is decreased, the edge region crashes annularly. Observed rapid mixture of the plasma in the limited region suggests that these sawtooth crashes are reconnection phenomena. Unlike previous experiments, no precursor oscillation has been observed.

Journal Article↗
PubMed2003

Coexistence of antiferromagnetism and superconductivity near the quantum criticality of the heavy-fermion compound CeRhIn5.

We report a study on the interplay between antiferromagnetism (AFM) and superconductivity (SC) in a heavy-fermion compound CeRhIn5 under pressure P=1.75 GPa. The onset of the magnetic order is evidenced from a clear split of 115In nuclear quadrupole resonance spectrum due to the spontaneous internal field below the Néel temperature T(N)=2.5 K. Simultaneously, bulk SC below T(c)=2.0 K is demonstrated by the observation of the Meissner diamagnetism signal whose size is the same as in the exclusively superconducting phase. These results indicate that the AFM coexists homogeneously with the SC at a microscopic level.

Journal Article↗
PubMed2003

Realistic Virtual Endoscopy of the ventricle system and haptic-based surgical simulator of hydrocefalus treatment.

New methods and software tools for automatic extraction of the ventricle system from magnetic resonance imagery (MRI) data, ventricle part classification, and realistic texturing are proposed to support Virtual Endoscopy (VE). Volume- and surface-based medical atlases are intensively used as templates in the methods. The processed ventricle-related surfaces are then utilized in a haptic-based system, which provides a surgeon with several basic functions simulating "virtual treatment" of hydrocephalus.

Cerebral Ventricles↗
PubMed2001

Unique spin dynamics and unconventional superconductivity in the layered heavy fermion compound CeIrIn5: NQR evidence.

We report measurements of the 115In nuclear spin-lattice relaxation rate ( 1/T1) between T = 0.09 and 100 K in the new heavy fermion (HF) compound CeIrIn5. At 0.4 < or = T< or = 100 K, 1/T1 is strongly T-dependent, which indicates that CeIrIn5 is much more itinerant than known Ce-based HFs. We find that 1/T1T, subtracting that for LaIrIn5, follows a (1 / T+straight theta)3/4 variation with straight theta = 8 K. We argue that this novel feature points to anisotropic, due to a layered crystal structure, spin fluctuations near a magnetic ordering. The bulk superconductivity sets in at 0.40 K below which the coherence peak is absent and 1/T1 follows a T3 variation, which suggests unconventional superconductivity with line-node gap.

Journal Article↗
PubMed2001

An accurate method of predicting mandibular growth potential based on bone maturity.

Mandibular growth prediction provides important information for planning treatment and for evaluating occlusal stability after treatment. At present, several methods can predict mandibular growth, but it is not clear which method is the most accurate. This study compared the predictive error of several methods by using skeletal maturity indicators. Twenty-two longitudinal cephalograms and hand-wrist radiographs of female subjects (average initial age, 8.3 years; final age, 18.4 years) were collected to construct the prediction formula. Another 22 female subjects (initial age, 10.8 years; final age, 18.6 years) were examined to compare differences between the predicted values and the actual values. Mandibular total length (condylion-gnathion) at the final stage can be accurately predicted by (1) the ossification events of the third middle phalanx and the radius, (2) the growth potential method, (3) the growth percentage method, (4) the multiple regression method, and (5) the growth chart method. Bone age as a parameter was calculated by both the Tanner-Whitehouse 2 (TW2) method and the computer-aided skeletal maturity assessment system (CASMAS) that we developed. The average error between the predicted length of condylion to gnathion and the actual length at the final stage for each method was (1) 3.0 mm; (2) 2.1 mm (TW2), 2.4 mm (CASMAS); (3) 2.3 mm (TW2), 2.6 mm (CASMAS); (4) 4.3 mm (TW2), 4.9 mm (CASMAS); and (5) 3.6 mm (TW2), 3.7 mm (CASMAS). The growth potential method and the growth percentage method were the most accurate predictors of mandibular growth potential.

Adolescent↗
PubMed2000

PCR survey of Hox genes in the crinoid and ophiuroid: evidence for anterior conservation and posterior expansion in the echinoderm Hox gene cluster.

To help elucidate the cluster organization of Hox genes in echinoderms, we amplified a homeobox region by polymerase chain reaction (PCR) and cloned and sequenced the PCR products for the comatulid crinoid Oxycomanthus japonicus and the ophiuroid Stegophiura sladeni. The crinoid had at least three anterior, four medial, and four posterior genes, and the ophiuroid had at least one anterior, three medial, and six (one of which being a possible trans-paralog) posterior genes. The survey of the crinoid detected all three anterior complements (PG1-3 genes). It was inferred that the Hox genes of each species are organized into a single cluster and that a novel cognate group of echinoderm posterior genes (tentatively termed HboxP9) exists among echinoderms in addition to the known posterior genes Hbox4, Hbox7, and Hbox10. The results, combined with the data of other echinoderm classes, strongly suggest that the presence of a single Hox gene cluster is a common feature among echinoderms and that the cluster has the general features of the deuterostome Hox gene cluster, i.e., the anterior conservation and posterior expansion. The results of the ophiuroid imply that the posterior genes in this class diversified after the phylum Echinodermata had been established.

Alleles↗
PubMed2000

[Difference in 201TlCl accumulation mechanism in brain tumors: a comparison of their Na(+)-K+ ATPase activities].

The accumulation levels of 201TlCl and Na(+)-K+ ATPase activity in tumor tissue were compared among glioblastoma, benign glioma and meningioma to study the difference in the mechanism of 201TlCl accumulation. The subjects were 19 cases comprised of 6 glioblastoma, 2 oligodendroglioma, 1 fibrillary astrocytoma, 1 pilocytic astrocytoma and 9 meningioma. Preoperative 201TlCl SPECT was performed in all the cases, and Thallium Index (TL index) was calculated by a ratio of 201TlCl in the tumor area and the contralateral area. In addition, cell membrane was extracted from the tumor tissue collected intraoperatively to determine Na(+)-K+ ATPase activity. No statistically significant difference in TL index was noted between the glioblastoma group (6.97 +/- 2.67) and the meningioma group (5.87 +/- 1.99). This fact showed that there was no difference in the accumulation level of 201TlCl between the two groups. On the other hand, the glioblastoma group indicated a higher value of Na(+)-K+ ATPase activity (49.13 +/- 43.76 mumole/hour/mg protein) than the meningioma group (7.73 +/- 13.84 mumole/hour/mg protein) (p < 0.05, t test). These results suggested the involvement of Na(+)-K+ ATPase activity in 201TlCl accumulation in glioblastoma and the influences of other accumulation mechanism than Na(+)-K+ ATPase activity such as the volume of intratumoral vascular bed in meningioma.

Adult↗
PubMed1999

Proteolipid protein gene duplications causing Pelizaeus-Merzbacher disease: molecular mechanism and phenotypic manifestations.

Pelizaeus-Merzbacher disease (PMD) is an X-linked disorder characterized by dysmyelination of the central nervous system (CNS) caused by mutations involving the proteolipid protein gene (PLP). In addition to point and frameshift mutations in the coding region, duplications involving the entire PLP have been recognized recently as a major genetic abnormality causing PMD. We devised an interphase fluorescence in situ hybridization (FISH) assay to establish an efficient screening test for PLP duplication. Thirteen patients from 11 Japanese PMD families were determined to have PLP duplications. This molecular diagnostic FISH test also readily detected female carriers. Molecular analysis revealed that the size of the duplication and location of the breakpoints showed striking variation. Fiber FISH demonstrated that the duplication is tandem in nature. Haplotype analysis indicated an intrachromosomal origin for the duplication. These results suggest that an unequal sister chromatid exchange in male meiosis is likely to be the major mechanism leading to the formation of the duplication. Patients with the duplication commonly present with a mild PMD phenotype. Two patients with an exceptionally severe clinical phenotype carried large duplications, suggesting that either the larger duplicated segment incorporates additional dosage-sensitive genes or that the location of the duplication junction may affect the phenotype.

Adolescent↗
PubMed1999

[Contralateral cerebellar infarction after aneurysmal clipping with pterional craniotomy: report of two cases].

A 77-year-old woman underwent right fronto-temporal craniotomy for a right ruptured IC-PC aneurysm (case 1), and a 44-year-old woman underwent right fronto-temporal craniotomy for a right ruptured BA-SCA aneurysm (case 2). They were clipped completely without any troubles during surgery. But postoperative CT scan demonstrated contralateral cerebellar infarction. We recognized left-hand tremor as a neurological deficit caused by cerebellar infarction in case 1. Concerning the mechanism of contralateral cerebellar infarction after pterional craniotomy, we think that it could be; --1) changing of venous blood flow by overdrainage of cerebrospinal fluid, 2) destruction of the bridging vein because of cerebral transformation with rapid decompression, 3) ischemia caused by brain retraction and compression during operation, 4) hypertension or hypoxia during operation, 5) crossed cerebellar diaschosis, and so on. In our 2 cases, we believe that perioperative CSF overdrainage caused the contralateral cerebellar infarction or CCD. To avoid this kind of infarction, we should try to take more protective and careful procedures as well as closer perioperative management.

Adult↗
PubMed1998

[201T1C1 accumulation dynamics in glioma with different grades of malignancy: an investigation using dynamic SPECT].

Dynamic SPECT was performed using 201TICI in a total of 21 gliomas, 14 cases of glioblastoma multiforme (GM) and 7 cases of anaplastic astrocytoma (AA), to investigate the relationship between test results and malignancy. The accumulation of isotope (counts/pixel) in the tumor was measured every 3 minutes with dynamic SPECT. The initial 3-minute value was reduced from subsequent accumulations (counts/minute) to obtain the time-activity curve (TAC). Thallium index (TL index), the ratio of 15-minute accumulation in the tumor to that in the same region of the contralateral normal brain, was also calculated. TL index was significantly higher (p < 0.05, Mann-Whitney test) in GM (6.25 +/- 1.97) than in AA (4.10 +/- 1.66), although no clear differential value could be determined between the two. TAC in the GM group showed that compared with the initial 3-minute value, accumulation increased significantly (p < 0.05) at every measurement point after isotope injection: 6 minutes, 0.660 +/- 0.671; 9 minutes, 1.322 +/- 1.319; 12 minutes, 1.315 +/- 1.632 and 15 minutes, 1.234 +/- 1.552. The increase in isotope accumulation in the tumor after 6 minutes or later was noted in 11 of the 14 cases in the GM group. In the AA group, however, there were no significant differences between the initial 3-minute value and value after 6 minutes (-0.283 +/- 0.462), 9 minutes (-0.574 +/- 0.681), 12 minutes (-0.690 +/- 0.611) and 15 minutes (-0.707 +/- 0.636) after isotope injection. A decrease in isotope accumulation in the tumor after 6 minutes or later was noted in 6 of the 7 cases in the AA group. Compared with static SPECT, dynamic SPECT, which can be performed easily and quickly, is more useful in clinical settings because of its high ability to differentiate the grade of malignancy of gliomas.

Adult↗
PubMed1997

A PCR survey of hox genes in the sea star, Asterina minor.

The sea star, Asterina minor, was surveyed for Hox genes using the method of PCR and subsequent sequence determination. Seven different Hox-type homeobox fragments and homeobox fragments of two other types, the Gbx-type and the Xlox-type, were identified. The results of comparative analysis with known homeobox sequences suggest that the sea star has only one Hox gene cluster including two genes of the anterior group, four genes of the medial group, and one gene of the posterior group. The existence of a gene of the cognate group 1 has not been known in echinoderm species. Each of the other fragments indicated a definite relationship with one of sea urchin homeoboxes. The hypothetical cluster in the sea star is consistent with the results published for another class of echinoderm, sea urchins, in the putative number of cluster. The present result provides strong evidence that a single Hox cluster is common to echinoderms and its structure in the anterior region is more similar to other deuterostomes than previously thought.

Amino Acid Sequence↗
PubMed1997

Neuronal maturation and N-acetyl-L-aspartic acid development in human fetal and child brains.

The developmental changes in N-acetyl-L-aspartic acid (NAA) were assessed in human fetal and child brains by means of high resolution proton magnetic resonance spectroscopy (MRS). NAA was detected in the cerebral cortex and white matter of fetuses of 16 weeks' gestation. NAA increased gradually from 24 weeks' gestation and remarkably from 40 weeks' gestation to 1 year of age. The developmental changes in tissue NAA in postnatal brains were found to be similar to those of NAA/Cr on clinical proton MRS. As the neuronal cell density in the cerebral cortex decreases with dendritic maturation, an increase in NAA with age may reflect the normal and abnormal development of axons, dendrites and synapses as well as neuronal soma.

Adolescent↗
PubMed1995

Progress of myelination in the human fetal spinal nerve roots, spinal cord and brainstem with myelin basic protein immunohistochemistry.

The early progress of myelination was studied, by means of myelin basic protein (MBP) immunohistochemistry and luxol-fast-blue (LFB) staining, in the spinal cord, spinal nerve roots and brainstem of 66 fetuses and neonates. The degree of myelination was classified from 1 (slight) to 4 (mature). MBP immunoreactivity exhibited slight LFB positivity. Myelination first occurred in the medial longitudinal fasciculus at 20 weeks of age, reaching degree 4 at 34 weeks, but began at 23-24 weeks in the other sites. Myelination of spinal nerve roots progressed with gestation and attained degree 4 at 35-36 weeks. The cuneate fasciculus also reached degree 4 at 34-36 weeks, but corticospinal tracts and solitary tracts, which exhibited long myelinating phases, were slow and incomplete at 40 weeks. This normal development of MBP and LFB myelination can be used for the assessment of delayed myelination in fetal and neonatal diseases.

Brain Stem↗