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A Fujiwara

Publications and source records attributed to A Fujiwara.

At least 19 recordsLinked to original sources
PubMed2006

Therapeutic efficacy of leukocytapheresis in a pregnant woman with severe active ulcerative colitis.

Leukocytapheresis has recently been used to induce remission in patients with ulcerative colitis (UC) who fail to respond to corticosteroids. We could not find a report in the literature on leukocytapheresis for UC with gestational exacerbation. We have recently encountered this unique condition and report the details here. A 30-year-old Japanese woman with left-sided severe UC was corticosteroid-dependent and had recurrence of the active disease during tapering of corticosteroid. She declined any dose increase and the use of any immunosuppressive agent because she was in the 13th week of pregnancy. Then, concomitant leukocytapheresis was performed without increasing the corticosteroid dose. Recovery was rapid and dramatic. Mucous and bloody stool decreased after the first session, and she had remission 2 weeks later. She underwent a total of four sessions without complications. After 6 weeks, she was discharged from our hospital and underwent maintenance treatment as an outpatient with mesalazine and corticosteroid tapering. Subsequently, she gave birth to a healthy baby girl by an uncomplicated vaginal delivery while keeping the remitted stage of UC.

Adult↗
PubMed2006

Valley polarization in Si(100) at zero magnetic field.

The valley splitting, which lifts the degeneracy of the lowest two valley states in a SiO(2)/Si(100)/SiO(2) quantum well, is examined through transport measurements. We demonstrate that the valley splitting can be observed directly as a step in the conductance defining a boundary between valley-unpolarized and -polarized regions. This persists to well above liquid helium temperature and shows no dependence on magnetic field, indicating that single-particle valley splitting and valley polarization exist in (100) silicon even at zero magnetic field.

Journal Article↗
PubMed2006

Near-infrared spectral results of asteroid Itokawa from the Hayabusa spacecraft.

The near-infrared spectrometer on board the Japanese Hayabusa spacecraft found a variation of more than 10% in albedo and absorption band depth in the surface reflectance of asteroid 25143 Itokawa. Spectral shape over the 1-micrometer absorption band indicates that the surface of this body has an olivine-rich mineral assemblage potentially similar to that of LL5 or LL6 chondrites. Diversity in the physical condition of Itokawa's surface appears to be larger than for other S-type asteroids previously explored by spacecraft, such as 433 Eros.

Journal Article↗
PubMed2006

The rubble-pile asteroid Itokawa as observed by Hayabusa.

During the interval from September through early December 2005, the Hayabusa spacecraft was in close proximity to near-Earth asteroid 25143 Itokawa, and a variety of data were taken on its shape, mass, and surface topography as well as its mineralogic and elemental abundances. The asteroid's orthogonal axes are 535, 294, and 209 meters, the mass is 3.51 x 10(10) kilograms, and the estimated bulk density is 1.9 +/- 0.13 grams per cubic centimeter. The correspondence between the smooth areas on the surface (Muses Sea and Sagamihara) and the gravitationally low regions suggests mass movement and an effective resurfacing process by impact jolting. Itokawa is considered to be a rubble-pile body because of its low bulk density, high porosity, boulder-rich appearance, and shape. The existence of very large boulders and pillars suggests an early collisional breakup of a preexisting parent asteroid followed by a re-agglomeration into a rubble-pile object.

Journal Article↗
PubMed2006

Touchdown of the Hayabusa spacecraft at the Muses Sea on Itokawa.

After global observations of asteroid 25143 Itokawa by the Hayabusa spacecraft, we selected the smooth terrain of the Muses Sea for two touchdowns carried out on 19 and 25 November 2005 UTC for the first asteroid sample collection with an impact sampling mechanism. Here, we report initial findings about geological features, surface condition, regolith grain size, compositional variation, and constraints on the physical properties of this site by using both scientific and housekeeping data during the descent sequence of the first touchdown. Close-up images revealed the first touchdown site as a regolith field densely filled with size-sorted, millimeter- to centimeter-sized grains.

Journal Article↗
PubMed2006

A comparative map of macrochromosomes between chicken and Japanese quail based on orthologous genes.

In order to develop a comparative map between chicken and quail, we identified orthologous gene markers based on chicken genomic sequences and localized them on the Japanese quail Kobe-NIBS linkage map, which had previously been constructed with amplified fragment length polymorphisms. After sequencing the intronic regions of 168 genes located on chicken chromosomes 1-8, polymorphisms among Kobe-NIBS quail family parents were detected in 51 genes. These orthologous markers were mapped on eight Japanese quail linkage groups (JQG), and they allowed the comparison of JQG to chicken macrochromosomes. The locations of the genes and their orders were quite similar between the two species except within a previously reported inversion on quail chromosome 2. Therefore, we propose that the respective quail linkage groups are macrochromosomes and designated as quail chromosomes CJA 1-8.

Animals↗
PubMed2006

Difference in stretching of sarcomeres between medial gastrocnemius and tibialis anterior by tibial lengthening: an experiment in rabbits.

PURPOSE: To compare the degree of stretching of sarcomeres--in the medial gastrocnemius versus the tibialis anterior--acutely extended by tibial lengthening. METHODS: The right lower legs of 6 New Zealand White rabbits were acutely distracted by 6.3 mm using an external fixator, whereas the left lower legs served as controls. Immediately after distraction, the ankle was dorsiflexed at 50 degrees and the knee flexed at 140 degrees, with respect to the posture of resting on the ground. Both legs were immersed in 10% buffered formalin for fixation, and the medial gastrocnemius and tibialis anterior were removed. Length of the 2 sarcomeres was measured by a laser diffraction technique using isolated muscle fibre bundles. RESULTS: The mean lengths of sarcomeres in the medial gastrocnemius and tibialis anterior were 3.0 microm and 2.3 microm in the lengthened legs, and 2.4 microm and 2.1 microm in control legs, respectively. The degree of stretching of corresponding sarcomeres was therefore 25% and 10%, this difference being significant (p<0.01). CONCLUSION: Sarcomeres of the medial gastrocnemius are more stretchable than those of the tibialis anterior following tibial lengthening.

Animals↗
PubMed2005

Construction of a genetic linkage map of Japanese quail (Coturnix japonica) based on AFLP and microsatellite markers.

The Japanese quail (Coturnix japonica) is a notably valuable egg and meat producer but has also been used as a laboratory animal. In the present study, we constructed a Japanese quail linkage map with 1735 polymorphic amplified fragment length polymorphisms markers, and nine chicken microsatellite (MS) markers, as well as sex and phenotypes of two genetic diseases; a muscular disorder (LWC) and neurofilament-deficient mutant (Quv). Linkage analysis revealed 578 independent loci. The resulting linkage map contained 44 multipoint linkage groups covering 2597.8 cM and an additional 218.2 cM was contained in 21 two-point linkage groups. The total map was 2816 cM in length with an average marker interval of 5.5 cM. The Quv locus was located on linkage group 5, but linkage was not found between the LWC locus and any of the markers. Comparative mapping with chicken using orthologous markers revealed chromosomal assignments of the quail linkage group 1 to chicken chromosome 2 (GGA2), 5 to GGA22, 2 to GGA5, 8 to GGA7, 27 to GGA11, 29 to GGA1 and 45 to GGA4.

Animals↗
PubMed2002

Activation of caspases in intestinal villus epithelial cells of normal and nematode infected rats.

BACKGROUND: Small intestinal epithelial cells (IEC) show apoptosis in physiological turnover of cells and in certain inflammatory diseases. AIMS: To investigate the role of caspases in the progression of IEC apoptosis in vivo. METHODS: IEC were separated along the villus-crypt axis from the jejunum of normal and Nippostrongylus brasiliensis infected rats at 4 degrees C. Caspases were examined by a fluorometric assay method, histochemistry, and immunoblotting. RESULTS: Villus cell rich IEC from normal rats exhibited a high level of caspase-3-like activity whereas activities of caspase-1, -8, and -9 were negligible. Immunoblotting analysis of villus cell rich IEC revealed partial cleavage of procaspase-3 into a 17 kDa molecule as well as cleavage of a caspase-3 substrate, poly(ADP-ribose) polymerase (PARP), whereas in crypt cell rich IEC, caspase-3 cleavage was less significant. Caspase-3 activity was also observed histochemically in villus epithelium on frozen sections of the normal small intestine. IEC prepared at 4 degrees C did not reveal nuclear degradation whereas subsequent incubation in a suspension at 37 degrees C induced intense nuclear degradation within one hour in accordance with increases in active caspase-3. This apoptosis was partially suppressed by the caspase inhibitor Z-VAD-fmk. Nematode infected animals showed villus atrophy together with significant increases in levels of caspase-3 in IEC but not of caspase-1, -8, or -9. CONCLUSION: Caspase-3 may have an important role in the physiological replacement of IEC as well as in progression of IEC apoptosis induced by nematode infection.

Animals↗
PubMed2001

Biomechanical evaluation of diagonal fixation in pedicle screw instrumentation.

STUDY DESIGN: Flexibility tests and finite element analyses were performed for the biomechanical evaluation of diagonal transfixation in pedicle screw instrumentation. OBJECTIVE: To assess the biomechanical advantages of diagonal transfixation compared with conventional horizontal transfixation. SUMMARY AND BACKGROUND DATA: A few pedicle screw instrumentation systems allow the use of cross-links in the diagonal direction. Such a diagonal transfixation is anticipated to improve the surgical construct stability, but its biomechanical qualities have not been completely evaluated. METHODS: Flexibility tests were performed on 10 calf lumbar spines (L2-L5). Specimens were subjected to pure moments up to 8.2 Nm in flexion, extension, lateral bending, and extension while the resulting movements of L3 and L4 were measured by a three-dimensional motion analysis system. The tested cases included (1) intact, (2) pedicle screw fixation without transfixation after total removal of the L3-L4 disc, (3) pedicle screw fixation with diagonal transfixation, and (4) pedicle screw fixation with horizontal transfixation. Three-dimensional finite element models of the tested surgical constructs were also developed by use of three-dimensional beam elements to investigate the effect of diagonal transfixation and horizontal transfixation on the construct stability and the corresponding stress changes in the screws. RESULTS: When compared with no transfixation, horizontal transfixation significantly improved the lateral bending and axial rotation stability by 15.7% and 13.9%, respectively, but there was no improvement of stability in flexion and extension. By contrast, diagonal transfixation significantly improved the flexion and extension stability by 12% and 10.7%, respectively, but not the lateral bending and axial rotation stability in comparison with no transfixation. Comparison between horizontal transfixation and diagonal transfixation showed that the stabilizing effect of diagonal transfixation was greater in flexion and extension (13% and 11%, P < 0.01) than that of horizontal transfixation but smaller in lateral bending (11%, P < 0.05) and axial rotation (6.6%, P > 0.1). Finite element model predictions of the motion changes were similar to the changes observed in flexibility tests. In horizontal transfixation, the load changes, compared with no transfixion, were a 0.02% increase in flexion-extension, a 27.5% increase in lateral bending, and a 58% decrease in axial rotation, and the magnitudes of the moments applied on both the right and left pedicle screws were identical. However, when diagonal transfixation was achieved by connecting the left superior screw and the right inferior screw, the loads in the left screw were increased by 11.5% in flexion-extension, 43.6% in lateral bending, and 7.9% in axial rotation, whereas the loads in the right screw were decreased by 10.9% in flexion-extension, increased by 0.06% in lateral bending, and decreased by 18.1% in axial rotation. CONCLUSIONS: The results of this study showed that diagonal transfixation provides more rigid fixation in flexion and extension but less in lateral bending and axial rotation in comparison with horizontal transfixation. Furthermore, greater stresses in the pedicle screws were predicted in the diagonal transfixation model. These limitations of diagonal transfixation should be considered carefully for clinical application.

Animals↗
PubMed2001

Reduced IP3 sensitivity of IP3 receptor in Purkinje neurons.

The inositol 1,4,5-trisphosphate receptor (IP3R) is highly expressed in Purkinje neurons (PNs) and is thought to be essential for the induction of long-term depression at parallel-fiber-PN synapses. Here, by imaging the fluorescence intensity of the low-affinity Ca2+ indicator inside the Ca2+ stores in the permeabilized single PNs, we analyzed the kinetics of Ca2+ release via the IP3R in controlled cytoplasmic environments. The rate of Ca2+ release is dependent on the IP3 concentration with an EC50 of 25.8 microM, which is > 20-fold greater than that of the IP3R in the isolated preparations or in peripheral cells. This property would be advantageous in inducing the release of Ca2+ in a localized space adjacent to the site of synaptic inputs.

Animals↗
PubMed2001

Morphologic changes in the lumbar intervertebral foramen due to flexion-extension, lateral bending, and axial rotation: an in vitro anatomic and biomechanical study.

STUDY DESIGN: A biomechanical and anatomic study with human cadaveric lumbar spine. OBJECTIVES: The purpose of this study is to examine the morphologic changes in the intervertebral foramen during flexion, extension, lateral bending, and axial rotation of the lumbar spine and to correlate these changes with the flexibility of the spinal motion segments. SUMMARY OF BACKGROUND DATA: Previous studies showed morphologic changes in the intervertebral foramen during flexion and extension; however, those changes during lateral bending and axial rotation were not well known. METHODS: There were 81 motion segments obtained from 39 human cadaveric lumbar spines (mean age 69 years). The motion segments were imaged with CT scanner with 1-mm thick consecutive sections. For biomechanical testing each motion segment was applied with incremental pure moments of flexion, extension, lateral bending, and axial rotation. Rotational movements of the motion segment were measured using VICON cameras. After application of the last load, the specimens were frozen under load, and then CT was performed with the same technique described above. Six parameters of the intervertebral foramen were measured, including foraminal width (maximum and minimum), foraminal height, disc bulging, thickness of ligamentum flavum, and cross-sectional area of the foramen. RESULTS: Flexion increased the foraminal width (maximum and minimum), height, and area significantly while significantly decreasing the disc bulging and thickness of ligamentum flavum (P < 0.05). However, extension decreased the foraminal width (maximum and minimum), height, and area significantly. Lateral bending significantly decreased the foraminal width (maximum and minimum), height, and area at the bending side, whereas lateral bending significantly increased the foraminal width (minimum), height, and area at the opposite side of bending. Likewise, axial rotation decreased the foraminal width (minimum) and area at the rotation side significantly while significantly increasing the foraminal height and foraminal area at the opposite side. The percent change in the foraminal area was found significantly correlated with the amount of segmental spinal motion except for the extension motion. CONCLUSIONS: This study showed that the intervertebral foramen of the lumbar spine changed significantly not only on flexion-extension but also on lateral bending and axial rotation. The percent change in cross-sectional foraminal area was correlated with the amount of segmental motion except for extension motions. Further studies are needed to assess the morphologic changes in the intervertebral foramen in vivo and to correlate clinically.

Adult↗
PubMed2001

Manipulation of elementary charge in a silicon charge-coupled device.

The ultimate limit in the operation of an electronic device is the manipulation of a single charge. Such a limit has been achieved in single-electron tunnelling devices. However, these devices are based on multiple tunnel barriers and conductive islands, which are complex structures to fabricate. Here we demonstrate another type of device that can also manipulate elementary charge, but which is more suitable for large-scale integration. The device consists of two closely packed silicon wire-MOSFETs, which are commonly used building blocks of electronic circuits. We have developed a scheme to generate and store holes in the channels of either of these MOSFETs. Subsequently, holes can be transferred between the two MOSFETs at the level of an elementary charge, and their exact position can be monitored. This single-charge transfer device, which is operated at 25 K, is in effect a charge-coupled device. This is also the first realization of a silicon-based device that manipulates elementary charge.

Journal Article↗
PubMed2001

Direct measurement of HDL cholesterol: method eliminating apolipoprotein E-rich particles.

It has been reported that the existing direct method of high density lipoprotein (HDL) cholesterol measures particles enriched with apolipoprotein E (apoE). The aim of our study was to investigate a new analytical protocol to directly measure HDL cholesterol that eliminates apoE-rich particles. The interactions of four lipoproteins (HDL(3), HDL(2), LDL, and VLDL + chylomicron) with surfactants, divalent cations, sugars, and lectins were investigated. By analyzing sera, HDL(3), and HDL(2), we examined the relationships among the measurements obtained by our protocol, a precipitation method using heparin-MnCl(2), and a commercially available kit for this direct method. A significant difference was found between the direct method and the heparin-MnCl(2) method, but not between our protocol and the heparin-MnCl(2) method. Multiple regression analysis showed that the difference between the direct method and the heparin MnCl(2) method is dependent on sources of apoE-rich HDL. In conclusion, our protocol enables a direct measurement of HDL cholesterol that eliminates apoE-rich particles.

Apolipoproteins E↗
PubMed2001

Improved fish lymphocyte culture for chromosome preparation.

Cytogenetic methodology is still underdeveloped in fishes compared with mammals. Culture condition for fish lymphocytes was optimized to improve chromosome preparation using the rainbow trout (Oncorhynchus mykiss) as a model after changing the combination of parameters such as mitogens, incubation periods, media, cell components, and freshness of blood. The optimized culture condition included isolation of lymphocytes from fresh blood by a stirring method, their culture in medium 199 supplemented with 10% FBS, 18 microg/ml of phytohemagglutinin (PHA-W) and 100 microg/ml of lipopolysaccharide (LPS) as mitogens, and harvested at 6 days after culture. This condition provided a notably increased mitotic index (MI) of 4.3-10.0% in rainbow trout lymphocytes. In addition, the condition was highly reproducible as shown by the similar level of MI in cultured lymphocytes from 181 individuals without failure. Applicability of this method in a wide range of fish groups was also proven with Ml of 1.1-13.3% in cultured lymphocytes from other 16 freshwater species of Acipenseridae, Anguillidae, Solmonidae, Cyprinidae, and Centrarchidae, and five marine species of Sparidae, Kyphosidae, Paralichthyidae, and Scorpaenidae. Chromosome preparations of improved quality by the present method were successfully applied for the replication R-banding with incorporation of 5-bromo-2'-deoxyuridine and direct R-banding fluorescence in situ hybridization.

Animals↗
PubMed2001

Sex identification by male-specific growth hormone pseudogene (GH-psi) in Oncorhynchus masou complex and a related hybrid.

It is often difficult to identify sexes of many fish species by conventional cytological method because of the lack of heteromorphic sex chromosomes. Isolation of sex-specific molecular markers is thus important for sexing and for understanding sex chromosome evolution in these species. We have identified genetic sexes by PCR-based male-specificity of a growth hormone pseudogene (GH-psi) in masu and Biwa salmon, two subspecies of the Oncorhynchus masou complex, and their hybrid Honmasu. PCRs with primers designed from sequences of chinook salmon GH genes amplified GH-I and GH-II fragments in both sexes, but a third GH-psi fragment was detected in predominant proportion of males and very few phenotypic females. The consistency of phenotypic sex with genetic sex identified by GH-psi for masu salmon, Biwa salmon and Honmasu was 93.1, 96.7 and 94%, respectively. The remaining individuals showed inconsistency or deviation from sex-specificity: a few phenotypic males lacked the GH-psi, whereas a few phenotypic females possessed the GH-psi. Sequence of the putative GH-psi fragment from such females was identical to that from genetic males, and shared about 95% homology with the corresponding GH-psi fragment from chinook salmon. This result confirmed that these females were really GH-psi-bearing individuals. PCR analyses with primers designed from masu salmon GH-psi gave identical results, indicating that the absence of GH-psi in a few males was not resulted from primer mismatching. These GH-psi-bearing females and GH-psi-absent males were more likely to originate from spontaneous sex reversion than from crossing-over between GH-psi and the sex determination gene/region.

Animals↗
PubMed2001

Effects of Ca2+ on flavin-linked complex enzymes in mitochondria isolated from eggs and embryos of sea urchin.

Mitochondria isolated from sea urchin embryos in early development show almost the same activities of cytochrome c oxidase and flavin-linked complex enzymes, which are estimated by cytochrome c reductases as in those isolated from unfertilized eggs. The activities of these cytochrome c reductases are inhibited by Ca2+ at above 10-5 M more strongly than cytochrome c oxidase. To investigate the changes in intramitochondrial Ca2+ concentration at fertilization, the activity of pyruvate dehydrogenase, another mitochondrial enzyme, was measured. The activity of this enzyme was controlled by phosphorylation and Ca2+-dependent dephosphorylation of the catalytic unit. The enzyme activity increased for 30 min after fertilization, decreased and became close to zero within ~60 min. Then, the activity appreciably increased again after hatching. This seems to reflect changes in the intramitochondrial Ca2+ concentration. The enzyme activity was enhanced by pre-incubation with Ca2+ at concentrations up to 10-5 M but was made quite low at above 10-4 M Ca2+ and 10-3 M adenosine triphosphate. Although the changes in pyruvate dehydrogenase activity observed at fertilization will reflect the changes in the intramitochondrial calcium concentration, the intramitochondrial Ca2+ concentration of unfertilized eggs cannot be estimated from these results because high (> 10-4 M) or low (10-6 M) Ca2+ can inhibit the enzyme. Measurement of respiration of a single egg showed that injection of ethyleneglycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid released the mitochondrial electron transport in the unfertilized egg. The possibility that changes in intramitochondrial calcium concentration occur at fertilization is discussed in relation to activation of both mitochondrial respiration and pyruvate dehydrogenase.

Animals↗