Biomedical subjects

Akihiro Yamashita

Publications and source records attributed to Akihiro Yamashita.

7 recordsLinked to original sources

PubMed2006

Stable top-up operation at SPring-8.

Top-up operation allows SPring-8 to provide highly stable X-ray beams with arbitrary filling patterns. The implementation of top-up operation is described, with a focus on the simultaneous achievement of stability of stored current, beam orbit, purity of an isolated single bunch, and beam injection efficiency. Stored-current fluctuations have been routinely reduced to a level of 10(-3). Stored-beam oscillation on frequent beam injection, which was originally regarded as the most serious problem, has been successfully suppressed to a sufficiently low level that it never perturbs imaging experiments. Current impurities in nominally empty buckets have been reduced to a level of 10(-9) over more than one week of operation, making possible the measurement of time-resolved spectra using high-current bunches. Finally, excellent injection efficiency, higher than 80%, is routinely obtained, even for small undulator gaps, which is critical for preventing radiation damage to insertion-device magnets and to reduce leakage radiation. The process of achieving highly stabilized top-up operation at SPring-8 and its utility for user experiments are described.

Electrons↗

PubMed2006

Transient suppression of PPARgamma directed ES cells into an osteoblastic lineage.

Osteoblasts and adipocytes are believed to share a common progenitor. Peroxisome proliferator-activated receptor gamma (PPARgamma) plays a key role in the switching of these two cell lineages. Here, we demonstrated the differentiation of ES cells into an osteoblastic lineage using siRNA against PPARgamma without the addition of any osteogenic factors. We found that PPARgamma-siRNA downregulated the expression of aP2 mRNA and lipid accumulation, whereas it upregulated the expression of osteocalcin and calcium deposition. These results suggested that ES cells were directed into an osteoblastic lineage. Therefore, transient suppression using PPARgamma-siRNA may be a novel tool to induce differentiation of ES cells into osteoblasts.

Adipocytes↗

PubMed2006

Venous malformation of the tongue in a child treated by sclerotherapy with ethanolamine oleate: a case report.

We describe a 3-year-old boy with a huge venous malformation (VM) in the tongue, which was treated by direct injection of ethanolamine oleate (EO). After the injection of 5% EO, the VM shrank and good tongue movement was obtained without problematic side effects. Our findings in this case suggest that sclerotherapy with EO is a safe and effective method for treating VM in the oral region.

Child, Preschool↗

PubMed2006

Monkey embryonic stem cells differentiate into adipocytes in vitro.

Production of functional adipocytes is important in adipocyte research and regenerative medicine. In this paper, we describe the differentiation of monkey embryonic stem (ES) cells into insulin-responsive adipocytes. Treatment of embryoid body (EB) outgrowth with adipogenic hormones induced the expression of adipocyte-specific genes, such as PPARgamma, C/EBPalpha, aP2, insulin receptor, and GLUT4. Expression of adipocytokines, leptin and adiponectin, was also detected. Furthermore, translocation of GLUT4 was observed by insulin stimulation in differentiated adipocytes. These results suggested that monkey ES cells can be a useful tool for studying adipogenesis in primate.

Adipocytes↗

PubMed2005

Efficient gene silencing and cell differentiation using siRNA in mouse and monkey ES cells.

Small interfering RNA (siRNA) has been widely used for suppressing gene expression in various organisms. Here, we describe efficient methods to suppress target genes (EGFP or Oct4) using siRNA in mouse and monkey ES cells, and differentiation. In mouse ES cells, FACS analysis revealed that EGFP expression was suppressed in 97% of transfected cells at 48 h after transfection. In addition, cells expressed Hand1 and Cdx2, which are the marker genes of trophoblast lineage by the transient suppression of Oct4. In the case of monkey ES cells, highly efficient suppression was achieved in 98% of cells at 96 h post-transfection using the Sendai virus (hemagglutinating virus of Japan, HVJ) envelope as a carrier of siRNA. These efficient transfection methods using synthetic siRNA should contribute to evaluate specific gene function in ES cells and can be used to differentiate ES cells into desired cell lineages.

Animals↗

PubMed2005

Osteoblastic differentiation of monkey embryonic stem cells in vitro.

Monkey embryonic stem (ES) cell is a useful tool for preclinical studies of regenerative medicine. In this paper, we investigated whether monkey ES cells can be differentiated into osteoblasts in vitro using factors known to promote osteogenesis. We prepared embryoid bodies (EB) in the presence of retinoic acid (RA) and subsequently differentiated in the medium containing either dexamethasone (DEX) or bone morphogenetic protein (BMP)-2 in addition to osteogenic supplements (OS), specifically ascorbic acid and beta-glycerophosphate. RA treatment during EB formation induced osteoblastic marker genes, such as collagen type 1, osteopontin, and Cbfa1. For the expression of osteocalcin, however, cultivation with medium containing either DEX or BMP-2 in addition to OS was required. These results showed that osteoblasts could be derived from monkey ES cells in vitro and BMP-2 + OS was effective to induce calcification.

Animals↗

PubMed2003

[Music therapy used on a patient in the terminal stage of cancer who narrated a tale based on her fantasy].

Music therapy was used on a patient in the terminal stage of cancer who described a fantastic tale built around her imagined pregnancy. We believe that psychiatric intervention was successful through the introduction of music therapy as part of her palliative treatment. Particularly notable in this case was that the patient dealt with the development of ascites by telling a fantastic tale related to a pregnancy--i.e., becoming pregnant with the therapist's child. Her tale started by statements such as "I am pregnant and suffering from morning sickness" and "I am in the third month of pregnancy with the child of my therapist." This progressed in parallel with the actual changes in her physiological symptoms. Among the attending physician, the patient, and her family, this imaginary tale was an important means of communication. The theme of pregnancy, love, and family developed from an unconscious dynamic process between the physician and patient, which could be interpreted as a family-related story originating in the mind of a terminally ill patient. Through this family romance with a major theme of pregnancy, the patient was able to sense her physical crises. This process may be thought of as a product of the so-called "mythgenerating capacity" under limited conditions, which was proposed by Ellenberger. Being aware of this situation, the attending physician and others in charge of her care did not insist on negating her story: instead they accepted her fantasy, and through it they succeeded in establishing psychiatric communications. The process may be considered a form of the narrative approach that is currently attracting attention. In this example, the "process of mourning" and "stages of accepting death" in the terminal state found an outlet in the creation of a fantasy. We believe that this case illustrates the important role of communication between the physician and a patient through the acceptance by the former of a fantastic tale given by the latter; and of a psychotherapeutic intervention, i.e., a sincere interaction between them through music therapy.

Aged↗