Biomedical subjects

K Ando

Publications and source records attributed to K Ando.

At least 19 recordsLinked to original sources

PubMed2006

Effects of glycine betaine on bone marrow death and intestinal damage by gamma rays and carbon ions.

In this study, we investigated the effects of glycine betaine (GB) on bone marrow death and intestinal damage by gamma rays or carbon ions. C(3)H/He female mice received an i.p.-injection of GB before or after whole-body irradiation with gamma rays or 50 keV microm(-1) carbon ions. The irradiated mice were observed to determine the mortality for 30 days after exposure. Mice were also killed at 3.5 days after the exposure to determine the intestinal damage. The numbers of crypts per transverse circumference were counted using a microscope. For the bone marrow death, GB (93 mg GB per mouse) significantly (p < 0.05) increased the percentage survival for both radiations. For the intestinal damage, GB (93 mg GB per mouse) significantly (p < 0.05) increased the crypt survival for gamma rays, but not for carbon ions. GB might be a potential protector against normal tissue damage as a side effect in radiotherapy.

Animals↗

PubMed2006

Maturation-dependent change and regional variations in acoustic stiffness of rabbit articular cartilage: an examination of the superficial collagen-rich zone of cartilage.

OBJECTIVE: The purpose of the study was to investigate maturation-dependent changes of acoustic (ultrasound) stiffness and other ultrasound features of articular cartilage in healthy rabbit knees. METHODS: Five groups of rabbits of various ages (3 weeks, 8 weeks, 6 months, 1 year, 2.5 years) consisting of five rabbits per group were examined. Signal intensity (index of stiffness), signal duration (index of surface irregularity) and interval between signals (index of thickness) of the ultrasound reflection from articular cartilage were examined at four sites: posterior lateral femoral condyle, posterior medial femoral condyle, lateral tibial plateau, and medial tibial plateau. The sites were observed macroscopically and microscopically with a light microscope and a polarized light microscope. RESULTS: At the lateral and medial condyles and the lateral tibial plateau, signal intensity was least in 3-week-old specimens. The intensity increased until 6 months or 1 year of age. At these sites, the signal durations and intervals between signals were least at the ages of 6 months or 1 year. At the medial tibial plateau, the intensity was the least at 2.5 years of age and the interval between signals was least at 3 weeks of age; there was no effect of age on signal duration. Cartilage surfaces of all specimens were smooth and no degenerative changes were macroscopically or microscopically evident. The surface brightness of cartilage under the polarized light microscope was consistent with signal intensity values. CONCLUSIONS: The response of articular cartilage to ultrasound was maturation-dependent. Acoustic properties differed from mechanical stiffness properties, which were determined using indentation. Ultrasound may detect properties of the surface collagen of the articular cartilage.

Aging↗

PubMed2006

Comparative study on DNA sequences of ribosomal DNA and cytochrome c oxidase subunit 1 of mitochondrial DNA among five species of gnathostomes.

The nucleotide sequences of partial 18S, complete internal transcribed spacer region 1 (ITS1), complete 5.8S, complete ITS2 and partial 28S of ribosomal DNA (rDNA) and cytochrome c oxidase subunit 1 of mitochondrial DNA (MCOI) from five species of gnathostomes (G. spinigerum, G. doloresi, G. nipponicum, G. hispidum and G. binucleatum with the former four species being distributed in Japan and Asia) that cause human gnathostomiasis were compared by direct polymerase chain reaction cycle-sequencing. The nucleotide sequences of each region of the18S (613 bp), 5.8S (158 bp) and 28S (598 bp) rDNA from the five species were almost identical. The ITS1 region was different in length for the five species. The nucleotide sequences of each region of ITS2 and partial MCO1 regions were different among the five species. Therefore, these two regions can be used as genetic markers for identification of worms.

Animals↗

PubMed2006

Expression of CD90 on keratinocyte stem/progenitor cells.

BACKGROUND: The identification and purification of keratinocyte stem cells (KSCs) that are capable of self-renewal and maintenance of differentiating cell populations could contribute both to our understanding of the biology of these cells, and to significant clinical applications, such as the culturing of keratinocytes for transplantation to severe burn wounds. Here, we report the detection of CD90(+) cells in cultured normal human epidermal keratinocytes and adult skin. OBJECTIVES: To investigate the biological function of CD90(+) and CD90(-) keratinocytes. METHODS: CD90(+) and CD90(-) keratinocytes were purified from adult skin and cultured keratinocytes using fluorescent activated cell sorting, and their biological abilities were analysed using both in vitro and in vivo assays. RESULTS: Flow cytometry (FCM) analysis identified approximately 18% of post-primary neonatal keratinocytes as CD90(+). However, during expansion of the culture, the expression level of CD90 rapidly decreased to about 2.5% at passage 10, while most of the keratinocytes maintained expression of alpha6 integrin. Purified CD90(+) keratinocytes demonstrated a sixfold higher cell growth rate than CD90(-) cells and the ability to form large (over 3 mm in diameter) colonies. We then quantitatively evaluated both populations using a previously described in vivo human epidermal cyst formation assay. Enhanced green fluorescent protein (EGFP)-labelled CD90(+) or CD90(-) keratinocytes were subcutaneously injected into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. Six weeks after transplantation, EGFP(+) cell clusters in human epidermal cysts were evaluated using image analysis software. EGFP(+) cell cluster areas in the basal layer, derived from EGFP(+) CD90(+) cells, were eightfold larger than clusters of EGFP(+) CD90(-) cells. Furthermore, immunohistochemical staining and FCM analysis indicated that CD90 was expressed in most of the basal layer of the normal human epidermis. CONCLUSIONS: These results indicated that CD90 is a useful marker for the detection of human KSC-enriched populations in cultured human keratinocytes.

Adult↗

PubMed2005

Origin of the tunnel anisotropic magnetoresistance in Ga(1-x)Mn(x)As/ZnSe/Ga(1-x)Mn(x)As magnetic tunnel junctions of II-VI/III-V heterostructures.

We investigated spin-dependent transport in magnetic tunnel junctions made of III-V Ga(1-x)Mn(x)As electrodes and II-VI ZnSe tunnel barriers. The high tunnel magnetoresistance (TMR) ratio up to 100% we observed indicates high spin polarization at the barrier/electrodes interfaces. We found anisotropic tunneling conductance having a magnitude of 10% with respect to the direction of magnetization to linearly depend on the magnetic anisotropy energy of Ga(1-x)Mn(x)As. This proves that the spin-orbit interactions in the valence band of Ga(1-x)M(x)As are responsible for the tunnel anisotropic magnetoresistance (TAMR) effect.

Journal Article↗

PubMed2005

Transplantation of human neural stem cells for spinal cord injury in primates.

Recent studies have shown that delayed transplantation of neural stem/progenitor cells (NSPCs) into the injured spinal cord can promote functional recovery in adult rats. Preclinical studies using nonhuman primates, however, are necessary before NSPCs can be used in clinical trials to treat human patients with spinal cord injury (SCI). Cervical contusion SCIs were induced in 10 adult common marmosets using a stereotaxic device. Nine days after injury, in vitro-expanded human NSPCs were transplanted into the spinal cord of five randomly selected animals, and the other sham-operated control animals received culture medium alone. Motor functions were evaluated through measurements of bar grip power and spontaneous motor activity, and temporal changes in the intramedullary signals were monitored by magnetic resonance imaging. Eight weeks after transplantation, all animals were sacrificed. Histologic analysis revealed that the grafted human NSPCs survived and differentiated into neurons, astrocytes, and oligodendrocytes, and that the cavities were smaller than those in sham-operated control animals. The bar grip power and the spontaneous motor activity of the transplanted animals were significantly higher than those of sham-operated control animals. These findings show that NSPC transplantation was effective for SCI in primates and suggest that human NSPC transplantation could be a feasible treatment for human SCI.

Animals↗

PubMed2005

Expression and characterization of disulfide bond use of oligomerized A2-Pancortins: extracellular matrix constituents in the developing brain.

The region-specific characteristics of the extracellular matrix are crucial for diverse functions in the brain. Pancortins/neuron-specific olfactomedin-related glycoproteins are components of the extracellular matrix. They comprise four alternatively spliced variants, Pancortin-1 to -4, which share a common portion, the B part, in the middle of their structure, have two pairs of alternatively spliced 5' regions, A1 and A2, and 3' regions, C1 and C2. Here we demonstrate that in mice, Pancortin-3 (A2-B-C1) and Pancortin-4 (A2-B-C2), which we have grouped together the A2-Pancortins, were transcribed early during the development of the brain in a region specific manner and were expressed very stably in vivo. They are N-glycosylated and secreted. Furthermore, we examined their ontogenetical expression profiles in the developing thalamus using antiserum against the common B region, since transient expressions of their mRNAs were notable there. In the developing thalami, they lasted long in oligomerized form even after the transcription of their mRNAs decreased to an undetectable level. Further analyses revealed that cysteine residues that are located in the common B part are important for homo- and hetero-oligomer formation of A2-Pancortins. When we substituted cysteine residues 45 and 47 with serine residues in that common B part, oligomerization of the A2-Pancortins was highly disturbed.

Age Factors↗

PubMed2005

The association of antidiuretic hormone levels with an attack of Meniere's disease.

OBJECTIVES: An elevation of the plasma antidiuretic hormone (ADH) levels has frequently been observed in Meniere's disease patients. However, little is known regarding the mechanism behind such an elevation of ADH level in Meniere's disease patients. Therefore, we measured the plasma ADH in Meniere's disease patients and other vertigo patients to elucidate the association between the ADH levels, stress levels and the development of Meniere's symptom. DESIGN AND SETTING: The plasma ADH levels and plasma osmotic pressure were determined in 23 definite Meniere's disease patients and 160 patients with other types of vertigo/dizziness. All participants were administered questionnaire regarding their psychological status including their stress levels. RESULTS: The ADH levels of Meniere's disease patients in the acute phase (5.80 +/- 1.37 pg/mL) were significantly higher in comparison with that of Meniere's disease patients in the remission phase (2.26 +/- 0.41 pg/mL) (P < 0.05). In other peripheral vertigo patients, the ADH level in the acute phase (1.71 +/- 0.23 pg/mL) was not significantly different from that in the remission phase (1.45 +/- 0.15 pg/mL). Meniere's disease patients in the acute phase had a significantly higher stress score (114 +/- 23) than Meniere's disease patients in the remission phase (56 +/- 13) (P < 0.05). However, there was no significant correlation between their stress score and the ADH levels. CONCLUSIONS: These results suggest that the elevation of the plasma ADH levels in Meniere's disease patients in the acute phase is, therefore, associated with the pathogenesis of Meniere's disease attacks rather than with stress.

Acute Disease↗

PubMed2005

Comparative assessment of the gelatin particle agglutination test and an enzyme-linked immunosorbent assay for diagnosis of strongyloidiasis.

The performances of the gelatin particle agglutination test (GPAT) and enzyme-linked immunosorbent assay (ELISA) for the diagnosis of strongyloidiasis with reference to the results of the agar plate culture technique (APCT) were evaluated with samples from 459 individuals from communities in northeast Thailand where strongyloidiasis is endemic. The prevalence of strongyloidiasis in five sample groups determined by GPAT varied between 29.3 and 61.5% (mean, 38.8%). ELISA and APCT, employed concurrently, gave lower prevalence rates of 27.5% (range, 21.6 to 42.1%) and 22.7% (range, 12.7 to 53.8%), respectively. By using APCT as the standard method, the sensitivity of GPAT was generally higher than that of ELISA (81 versus 73%). The specificity of GPAT was slightly lower than that of ELISA (74 versus 86%). The resulting GPAT titers exhibited positive linear relationships with the ELISA values (optical density at 490 nm) (P < 0.05), which suggests that the GPAT titer also reflects the levels of specific antibody comparable to those reflected by the ELISA values. Based on the relative ease and simplicity of use of the technique as well as the acceptable rates of sensitivity and specificity of the test, GPAT is more practical for screening for strongyloidiasis than the conventional ELISA.

Agar↗

PubMed2004

Characterization of 4-O-methyl-ascochlorin-induced apoptosis in comparison with typical apoptotic inducers in human leukemia cell lines.

Apoptosis can be induced by various stimuli such as the ligands of death receptors, chemotherapeutic drugs and irradiation. It is generally believed that chemotherapeutic drugs induce mitochondrial damage, cytochrome c release and activation of caspase-9, leading to apoptosis. Here, we found that an isoprenoid antibiotic, 4-O-methyl ascochlorin, significantly induces typical apoptotic events in Jurkat cells including the degradation of poly (ADP-ribose) polymerase, DNA fragmentation, activation of caspase-3, -9 and -8, and cytochrome c release from mitochondria. Similar to Fas stimulation, 4-O-methyl ascochlorin but not staurosporine, cycloheximide and actinomycin D, induced apoptosis in SKW6.4 cells, in which apoptosis is strongly dependent on death-inducing signaling-complex. Bcl-2 overexpression in Jurkat cells completely suppressed the apoptosis, but procaspase-9 processing was partially induced. A caspase-8 inhibitor, IETD-fmk, effectively suppressed poly (ADP-ribose) polymerase cleavage and cytochrome c release. However, 4-O-methyl ascochlorin induced apoptosis in Jurkat cells deficient of caspase-8 or Fas-associated death domain protein. These results suggest that 4-O-methyl ascochlorin induces apoptosis through the mechanism distinct from conventional apoptosis inducers.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Complex chromosomal rearrangements induced in vivo by heavy ions.

It has been suggested that the ratio complex/simple exchanges can be used as a biomarker of exposure to high-LET radiation. We tested this hypothesis in vivo, by considering data from several studies that measured complex exchanges in peripheral blood from humans exposed to mixed fields of low- and high-LET radiation. In particular, we studied data from astronauts involved in long-term missions in low-Earth-orbit, and uterus cancer patients treated with accelerated carbon ions. Data from two studies of chromosomal aberrations in astronauts used blood samples obtained before and after space flight, and a third study used blood samples from patients before and after radiotherapy course. Similar methods were used in each study, where lymphocytes were stimulated to grow in vitro, and collected after incubation in either colcemid or calyculin A. Slides were painted with whole-chromosome DNA fluorescent probes (FISH), and complex and simple chromosome exchanges in the painted genome were classified separately. Complex-type exchanges were observed at low frequencies in control subjects, and in our test subjects before the treatment. No statistically significant increase in the yield of complex-type exchanges was induced by the space flight. Radiation therapy induced a high fraction of complex exchanges, but no significant differences could be detected between patients treated with accelerated carbon ions or X-rays. Complex chromosomal rearrangements do not represent a practical biomarker of radiation quality in our test subjects.

Aged↗

PubMed2004

Differentially expressed Maf family transcription factors, c-Maf and MafA, activate glucagon and insulin gene expression in pancreatic islet alpha- and beta-cells.

A basic-leucine zipper transcription factor, MafA, was recently identified as one of the most important transactivators of insulin gene expression. This protein controls the glucose-regulated and pancreatic beta-cell-specific expression of the insulin gene through a cis-regulatory element called RIPE3b/MARE (Maf-recognition element). Here, we show that MafA expression is restricted to beta-cells of pancreatic islets in vivo and in insulinoma cell lines. We also demonstrate that c-Maf, another member of the Maf family of transcription factors, is expressed in islet alpha-cells and in a glucagonoma cell line (alphaTC1), but not in gamma- and delta-cells. An insulinoma cell line, betaTC6, also expressed c-Maf, albeit at a low level. Chromatin immunoprecipitation assays demonstrated that Maf proteins associate with insulin and glucagon promoters in beta- and alpha-cell lines, respectively. c-Maf protein stimulated glucagon promoter activity in a transient luciferase assay, and activation of the glucagon promoter by c-Maf was more efficient than by the other alpha-cell-enriched transcription factors, Cdx2, Pax6, and Isl-1. Furthermore, inhibition of c-Maf expression in alphaTC1 cells by specific short hairpin RNA resulted in marked reduction of the glucagon promoter activity. Thus, c-Maf and MafA are differentially expressed in alpha- and beta-cells where they regulate glucagon and insulin gene expression, respectively.

Animals↗

PubMed2003

Washout measurement of radioisotope implanted by radioactive beams in the rabbit.

Washout of 10C and 11C implanted by radioactive beams in brain and thigh muscle of rabbits was studied. The biological washout effect in a living body is important in the range verification system or three-dimensional volume imaging in heavy ion therapy. Positron emitter beams were implanted in the rabbit and the annihilation gamma-rays were measured by an in situ positron camera which consisted of a pair of scintillation cameras set on either side of the target. The ROI (region of interest) was set as a two-dimensional position distribution and the time-activity curve of the ROI was measured. Experiments were done under two conditions: live and dead. By comparing the two sets of measurement data, it was deduced that there are at least three components in the washout process. Time-activity curves of both brain and thigh muscle were clearly explained by the three-component model analysis. The three components ratios (and washout half-lives) were 35% (2.0 s), 30% (140 s) and 35% (10 191 s) for brain and 30% (10 s), 19% (195 s) and 52% (3175 s) for thigh muscle. The washout effect must be taken into account for the verification of treatment plans by means of positron camera measurements.

Animals↗

PubMed2003

Room-temperature ferromagnetism in a II-VI diluted magnetic semiconductor Zn(1-x)Cr(x)Te.

The magnetic and magneto-optical properties of a Cr-doped II-VI semiconductor ZnTe were investigated. Magnetic circular dichroism measurements showed a strong interaction between the sp carriers and localized d spins, indicating that Zn(1-x)Cr(x)Te is a diluted magnetic semiconductor. The Curie temperature of the film with x=0.20 was estimated to be 300+/-10 K, which is the highest value ever reported for a diluted magnetic semiconductor in which sp-d interactions were confirmed. In spite of its high Curie temperature, Zn(1-x)Cr(x)Te film shows semiconducting electrical transport properties.

Journal Article↗

PubMed2003

Serum stem cell growth factor for monitoring hematopoietic recovery following stem cell transplantation.

Stem cell growth factor (SCGF) is a novel cytokine for primitive hematopoietic progenitor cells. Although it has burst-promoting activity and granulocyte/macrophage colony-promoting activity in vitro, its significance in hematopoiesis in vivo has not been elucidated. In this study, we have established enzyme-linked immunosorbent assay (ELISA) to quantify human SCGF and measured serum cytokines in normal volunteers and 27 patients undergoing stem cell transplantation (SCT), including six autologous and 21 allogeneic transplants. SCGF levels gradually increased after SCT regardless of graft-versus-host disease or type of transplant. The maximum level of SCGF was observed during the rapid granulocyte recovery phase in patients subjected to an autologous transplantation, and during the granulocyte stabilization phase in allogeneic patients. SCGF levels in PBSCT patients began to rise earlier than in BMT patients. Two patients with no increment of SCGF after SCT showed delayed engraftment. The source of SCGF was further analyzed by RT-PCR and we found that SCGF was highly expressed in bone marrow (BM) CD34(+) and CD34(-)CD33(+) cells, but not in BM CD34(-)CD33(-) cells, BM stromal cells and peripheral blood cells. The cell population expressing SCGF in BM possess the colony-forming cell activity. Therefore, serum SCGF can be an indicator of hematopoietic recovery following SCT.

Adolescent↗

PubMed2003

Isolation and characterization of an alternatively spliced variant of transcription factor Islet-1.

The LIM homeodomain protein Islet-1 (Isl1), one of the earliest markers for motor neuron differentiation, is also expressed in all classes of islet cells in the pancreas. Isl1 is known to bind and regulate the promoters of the insulin, glucagon and somatostatin genes. In this study, we describe isolation of a novel isl1 cDNA species from the mouse islet beta cell line betaTC6, which arose from the utilization of an alternative splicing acceptor site in the fifth exon. This shorter cDNA encodes an Isl1 isoform (Isl1-beta) lacking the carboxy-terminal 23 amino acids of the previously reported product Isl1-alpha. Although the level of isl1-beta mRNA is much lower than that of isl1-alpha, isl1-beta is preferentially expressed in murine insulinoma cell lines but not in glucagonoma cell line. Upon transient transfection, both Isl1-alpha and Isl1-beta accumulate in the nuclei of murine insulinoma cells. We found that Isl1-beta is a relatively more potent transcriptional activator of the insulin promoter than Isl1-alpha and that the Isl1-alpha isoform undergoes phosphorylation. Therefore, the transcriptional activity of Isl1 is potentially regulated by the alternative splicing of its mRNA and by phosphorylation.

Alternative Splicing↗

PubMed2002

Expression of tenascin in bile duct cancer of hamster liver by combined treatment of dimethylnitrosamine with Opisthorchis viverrini infections.

Tenascin is an extracellular matrix glycoprotein known to be an essential factor for the modulation of reciprocal interactions between the epithelium and mesenchyme during embryogenesis and tumourigenesis. The interactions between the expression of tenascin in the liver of Syrian golden hamster and the development of bile duct cancer in an Opisthorchis viverrini-associated cholangiocarcinoma model were investigated. The tenascin was expressed in connective tissues surrounding the dilated ducts, ductal rims and the stroma of cancers, and strongly in the stroma flame of necrotic cancer nodules. The mRNA signal for tenascin was also recognized in the stroma cells. The potential roles of tenascin as prognostic tumour markers are discussed.

Animals↗

PubMed2002

Nitric oxide-mediated bystander effect induced by heavy-ions in human salivary gland tumour cells.

PURPOSE: To investigate the signal factor and its function in the medium-mediated bystander effect during heavy-ion irradiation of human salivary gland (HSG) neoplastic cells. MATERIALS AND METHODS: Unirradiated recipient HSG cells were co-cultivated with HSG donor cells irradiated with 290 MeV/u carbon beams having different LET values. Cell proliferation and micronucleus (MN) induction in recipient cells with and without treatment of a NO scavenger (PTIO) were measured and the concentration of nitrite in the co-culture medium was detected. As a direct control, the effects of a nitric oxide (NO) generator (sper/NO) on cell proliferation and MN induction were also examined. RESULTS: Increases in cell proliferation and MN induction were found in the recipient HSG cells as a result of co-culturing and cell proliferation was obviously enhanced during a further subculture. In comparison with 13keV/microm, 100keV/microm carbon-ion irradiation was found to be a more efficient inducer of the medium-mediated bystander effect. The treatment of cells by PTIO resulted in elimination of such effects, which supports a role for NO in the medium-mediated bystander effect. As an oxidization product of NO, nitrite was detected in the co-culture medium, and the dose-response for its concentration was similar to that of cell proliferation and MN induction in the recipient cells. When the HSG cells were treated by sper/NO with a concentration of less than 20 microM cell proliferation was enhanced, whereas MN increased along with sper/NO concentration. CONCLUSION: NO participated in the medium-mediated bystander effects on cell proliferation and MN induction, depending on the LET of irradiation.

Cell Division↗