Koji Kanayama | Kyushu University (original) (raw)

Papers by Koji Kanayama

Historia Scientiarum Second Series International Journal of the History of Science Society of Japan, Mar 31, 2013

This paper examines the relationship between Soviet scientific community and authority in the Sta... more This paper examines the relationship between Soviet scientific community and authority in the Stalin era by investigating how specialists of physical sciences and communist ideologues deal with interpretation of physical theories or concepts in the 1920s and 1930s. Soviet physico-philosophical disputes have often been regarded as a persistent attack on modem physical theories by well allied ideologues or ignoramuses. Minute study of historical documents with a consideration of socio-political context tells us, however, that this view must be radically revised. Attacks on leading physicists were not well formed, except for the comparatively short period of the Great Terror. Physicists also sought to find the way of description of physics, which is compatible with Marxist ideology dialectical materialism. We will suggest that it will be suitable to grasp the process of dispute as one of acquiring "Soviet Newspeak", not as a success on showing the correctness or usefulness of physics by leading physicists.

Plastic and Reconstructive Surgery - Global Open, 2015

Although various injection techniques of hyaluronic acid (HA) filler for facial rejuvenation have... more Although various injection techniques of hyaluronic acid (HA) filler for facial rejuvenation have been developed, correction of deep wrinkles/grooves, such as the nasolabial fold (NLF), with intradermal or subdermal injections remains difficult. We tested the intradermal HA injection method to place multiple HA struts by (1) inserting a small needle perpendicularly to the wrinkle and (2) injecting HA as intradermal struts with the skin fully stretched by the practitioner&amp;amp;amp;#39;s fingers. The results of both NLFs in 10 patients suggest that this technique improves NLFs and maintain the effects more consistently than conventional techniques, although the effects of both methods were almost lost after 6 months. Selective and/or combined application of this technique may enhance the current approach to facial rejuvenation with dermal fillers.

Regenerative medicine, Jan 6, 2015

Despite the clinical potential of adipose-derived stem/stromal cells (ASCs), there are some clini... more Despite the clinical potential of adipose-derived stem/stromal cells (ASCs), there are some clinical difficulties due to the regulation of cell therapies. Micronized cellular adipose matrix (MCAM) injectable was prepared through selective extraction of connective tissue fractions in fat tissue only through mechanical minimal manipulation procedures. It retained some capillaries and ASCs, but most adipocytes were removed. The presence of viable ASCs, vascular endothelial cells was confirmed and ASCs of MCAM kept intact mesenchymal differentiation capacity. In diabetic mice, skin wounds treated with MCAM showed significantly accelerated healing compared with phosphate-buffered saline-treated ones. The proven potential of MCAM to accelerate healing in ischemic diabetic ulcers may offer a simple, safe and minimally invasive means for tissue repair and revitalization.

Stem cells translational medicine, Jan 22, 2015

: Three-dimensional culture of mesenchymal stem/stromal cells for spheroid formation is known to ... more : Three-dimensional culture of mesenchymal stem/stromal cells for spheroid formation is known to enhance their therapeutic potential for regenerative medicine. Spheroids were prepared by culturing human adipose-derived stem/stromal cells (hASCs) in a non-cross-linked hyaluronic acid (HA) gel and compared with dissociated hASCs and hASC spheroids prepared using a nonadherent dish. Preliminary experiments indicated that a 4% HA gel was the most appropriate for forming hASC spheroids with a relatively consistent size (20-50 µm) within 48 hours. Prepared spheroids were positive for pluripotency markers (NANOG, OCT3/4, and SOX-2), and 40% of the cells were SSEA-3-positive, a marker of the multilineage differentiating stress enduring or Muse cell. In contrast with dissociated ASCs, increased secretion of cytokines such as hepatocyte growth factor was detected in ASC spheroids cultured under hypoxia. On microarray ASC spheroids showed upregulation of some pluripotency markers and downregulation of genes related to the mitotic cell cycle. After ischemia-reperfusion injury to the fat pad in SCID mice, local injection of hASC spheroids promoted tissue repair and reduced the final atrophy (1.6%) compared with that of dissociated hASCs (14.3%) or phosphate-buffered saline (20.3%). Part of the administered hASCs differentiated into vascular endothelial cells. ASC spheroids prepared in a HA gel contain undifferentiated cells with therapeutic potential to promote angiogenesis and tissue regeneration after damage. This study shows the therapeutic value of human adipose-derived stem cell spheroids prepared in hyarulonic acid gel. The spheroids have various benefits as an injectable cellular product and show therapeutic potential to the stem cell-depleted conditions such as diabetic chronic skin ulcer.

Regenerative Medicine, 2015

Cells, tissues, organs, 2014

Ionizing radiation is often used to treat progressive neoplasms. However, the consequences of lon... more Ionizing radiation is often used to treat progressive neoplasms. However, the consequences of long-term radiation exposure to healthy skin tissue are poorly understood. We aimed to evaluate the short- and long-term radiation damage to healthy skin of the same irradiation given either as single or fractional doses. C57BL/J6 mice were randomly assigned to one of three groups: a control and two exposure groups (5 Gy ×2 or 10 Gy ×1). The inguinal area was irradiated (6-MeV beam) 1 week after depilation in the treatment groups. Skin samples were evaluated macroscopically and histologically for up to 6 months after the final exposure. After anagen hair follicle injury by irradiation, hair cycling resumed in both groups, but hair graying was observed in the 10 Gy ×1 group but not in the 5 Gy ×2 group, suggesting the dose of each fractional exposure is more relevant to melanocyte stem cell damage than the total dose. On the other hand, in the long term, the fractional double exposures induc...

Plastic and Reconstructive Surgery, 2015

Plastic and reconstructive surgery, Jan 20, 2015

Recent research indicates that the adipose tissue of non-vascularized grafts is completely remode... more Recent research indicates that the adipose tissue of non-vascularized grafts is completely remodeled within 3 months, although origins of next-generation cells are unclear. Inguinal fat pads of GFP mice and wild-type mice were cross-transplanted beneath the scalp. At 1, 2, 4, and 12 weeks post-transplantation, grafted fat was harvested, weighed and analyzed through immunohistochemistry, whole-mount staining, and flow cytometry of cell isolates. Bone marrow of GFP mice was transplanted to wild-type mice (after irradiation). Eight weeks later, these mice also received fat grafts, which were analyzed as well. The majority of host-derived cells detected during remodeling of grafted fat were macrophages (>90% at early stage; 60% at 12 weeks). Cell origins were analyzed at 12 weeks (i.e., when completely regenerated). At this point, mature adipocytes largely were derived from adipose stem/stromal cells (ASCs) of grafts. Although vascular wall constituents chiefly were graft-derived, va...

Plastic and reconstructive surgery. Global open, 2014

Hyperbaric oxygenation has been used for various purposes, but its clinical application is limite... more Hyperbaric oxygenation has been used for various purposes, but its clinical application is limited due to its pulmonary toxicity. We evaluated the therapeutic value of normobaric hyperoxygenation (NBO) for vascularized and nonvascularized tissue transplantation. Tissue oxygen partial pressure (PtO2) was measured for various organs in mice under inspiratory oxygen of 20%, 60%, or 100%. A rectangular skin flap (1 × 4 cm) or a composite skin graft (2 × 2 cm) was made on the back of mice, which were housed under 20% or 60% oxygen for the first 3 days after surgery. Cell survival was also examined in organ culture skin samples. PtO2 varied among tissues/organs, but increased depending on inspiratory oxygen concentration in all tissues/organs. Although NBO with 100% O2 was toxic, NBO with 60% O2 was safe even when used continuously for a long period. NBO did not significantly improve survival of the rectangular skin flap. On the other hand, in the composite skin graft model, the engraftme...

Plastic and reconstructive surgery, 2014

Fat grafting is a promising modality for soft-tissue augmentation/reconstruction. However, grafte... more Fat grafting is a promising modality for soft-tissue augmentation/reconstruction. However, grafted fat tissue is not initially perfused and relies on plasmatic diffusion from the recipient bed until revascularization occurs. The authors evaluated the therapeutic effects of normobaric hyperoxygenation for enhancing fat graft retention. Aspirated human fat tissue was cultured under tissue hypoxia (1% oxygen), normoxia (6%), and hyperoxia (20%) levels, and evaluated for adipocyte viability. Inguinal fat pads were autografted under mouse scalps (n=36), and mice were housed in either 20% (control) or 60% (normobaric hyperoxygenation) atmospheric oxygen for the first 3 days, and then returned to normoxia. Samples harvested at 0, 1, 2, 4, 8, and 12 weeks were analyzed immunohistochemically for adipocyte viability and regeneration. Organ culture adipocytes died more quickly under lower oxygen tensions; thus, hyperoxygenation of recipient tissues may delay adipocyte death after fat grafting....

Stem cells translational medicine, 2015

Stage-specific embryonic antigen-3 (SSEA-3)-positive multipotent mesenchymal cells (multilineage ... more Stage-specific embryonic antigen-3 (SSEA-3)-positive multipotent mesenchymal cells (multilineage differentiating stress-enduring [Muse] cells) were isolated from cultured human adipose tissue-derived stem/stromal cells (hASCs) and characterized, and their therapeutic potential for treating diabetic skin ulcers was evaluated. Cultured hASCs were separated using magnetic-activated cell sorting into positive and negative fractions, a SSEA-3(+) cell-enriched fraction (Muse-rich) and the remaining fraction (Muse-poor). Muse-rich hASCs showed upregulated and downregulated pluripotency and cell proliferation genes, respectively, compared with Muse-poor hASCs. These cells also released higher amounts of certain growth factors, particularly under hypoxic conditions, compared with Muse-poor cells. Skin ulcers were generated in severe combined immunodeficiency (SCID) mice with type 1 diabetes, which showed delayed wound healing compared with nondiabetic SCID mice. Treatment with Muse-rich cell...

Plastic and Reconstructive Surgery, 2014

Fat grafting is promising, but clinical outcomes are not always predictable. The mechanisms of ti... more Fat grafting is promising, but clinical outcomes are not always predictable. The mechanisms of tissue revascularization/regeneration, and tissue necrosis and subsequent absorption/fibrosis of the graft, are poorly understood. An autologous inguinal fat pad was transplanted under the scalp of mice, and detailed cellular events during the first 3 months were investigated with immunohistochemistry. Except for the most superficial surviving zone, death of all adipocytes was confirmed at 1 week. Perilipin-positive small new adipocytes appeared at 1 week and peaked in number at 4 weeks in the regenerating zone (the second zone). In the most central necrotizing zone, adipogenesis did not occur and many inflammatory cells were observed after 2 weeks. CD34+/Ki67+ proliferating adipose stem/progenitor cells were seen at 1 to 4 weeks, but the majority of proliferating cells were MAC2+ monocytes/macrophages. Although CD206+ M1 macrophages surrounded oil droplets for phagocytosis, CD206+ M2 macrophages appeared in areas where adipocyte replacement failed and formed multiple layers for cicatrization of oil drop spaces. Adipogenesis was complete by 12 weeks, but stabilization of nonregenerated areas was still ongoing at that time. Lipid droplets derived from dead adipocytes were absorbed slowly and thus aided adipose remodeling by maintaining the space until adipocyte regeneration. Dynamic remodeling after fat grafting was confirmed. Adipocyte fate differed, depending on the microenvironment: intact survival, replacement with a new adipocyte, or replacement with cicatrization/oil cyst. This detailed understanding will help refine surgical grafting procedures and postoperative evaluation.

Journal of Materials Science, 1991

Electro-conductive ZrB2-based composite ceramics, containing SiC and B4C, were machined with an e... more Electro-conductive ZrB2-based composite ceramics, containing SiC and B4C, were machined with an electro-discharge machining (EDM) process. The EDMed surfaces were covered with resolidified ZrB2 layers. Many open pores and surface cracks were observed on the surfaces. The strength degradation of the ceramics caused by machining was evaluated by three point bending tests of the partially EDMed bending specimens. The effects

Heteroatom Chemistry, 2001