The osteocytic cytoplasmic processes show regularly-arranged three-dimensional structure, a cellular network called osteocytic lacunar-canalicular system (OLCS). We have demonstrated the ultrastructure of the cellular network of OLCS by means of a structured illumination microscope method (SIM) and a Focused Ion Beam-Scanning Electron Microscope (FIB-SEM). We also attempted to localize exogenously-administered minodronate, a new generation of bisphosphonate, as well as calcium deposition onto the bone forming surface, using an isotope microscope system. Recent devised microscopic technique may provide new insights in the research field of bone.

Osteocyte

Source

Cite

Citations (2)

Histological observation on the initial stage of vascular invasion into the secondary ossification of murine femoral epiphyseal cartilage

Biomedical Research (2021)

Keiji Hashimoto Tomoka Hasegawa Tomomaya Yamamoto Hiromi Hongo Y IMIN

It remains unknown whether the histology of vascular invasion during secondary ossification of epiphyseal cartilage is the same as that seen in primary ossification; we examined the initial processes of vascular invasion of secondary ossification in the murine femora. Many endomucin-immunoreactive blood vessels gathered at the central region of the articular surface, and buds of soft tissue, including glomerular loops of endomucin-immunoreactive blood vessels and TNALPase- immunopositive osteoblastic cells accompanied by TRAP-positive osteoclasts, had begun to invade the epiphyseal cartilage. The invading soft tissues formed cartilage canals displaying MMP9 immunoreactivity in the tip region, and cartilaginous collagen fibrils were not visible in the vicinity of the vascular wall of the blood vessels. Thus, the histological profile marked by invading glomerular vasculature and the erosion of the cartilage matrix near the vascular walls during secondary ossification differs from that seen during primary ossification.

Histology

Ossification center

10.2220/biomedres.42.139

Cite

Citations (0)

Altered distribution of bone matrix proteins and defective bone mineralization in klotho-deficient mice

Bone (2013)

Muneteru Sasaki Tomoka Hasegawa Tamaki Yamada Hiromi Hongo Paulo Henrique Luiz de Freitas

matrix Gla protein

Klotho

Bone matrix

Matrix (chemical analysis)

Bone cell

Osteocyte

10.1016/j.bone.2013.08.008

Cite

Citations (38)

Biological application of focus ion beam-scanning electron microscopy (FIB-SEM) to the imaging of cartilaginous fibrils and osteoblastic cytoplasmic processes

Journal of Oral Biosciences (2016)

Tomoka Hasegawa Takashi Endo Erika Tsuchiya Ai Kudo Shen Zhao

Osteoid

Trabecula (gastropod)

Matrix (chemical analysis)

10.1016/j.job.2016.11.004

Cite

Citations (22)

[Encouragement for developing research mind of dental students].

PubMed (2013)

Norio Amizuka Hiromi Hongo Yukina Miyamoto Tomoka Hasegawa Muneteru Sasaki

The School of Dental Medicine in Japan nurtures well-trained professionals who are at the cutting edge of the present knowledge in the fields of Dentistry and Dental Technology. As an important part of its mission, many Schools of Dental Medicine in Japan, including Hokkaido University, also encourages dental students to pursue basic research in the many aspects of Dentistry. It is of importance to cultivate research-minded students in Dental Medicine. Laboratory assignment conducted by the School of Dental Medicine, Hokkaido University, is one process of education curriculum to assign students in the fifth and sixth grade to laboratories of basic sciences. Every dental student should belong to one laboratory, which accepts the fixed number of the students. By means of the research activity of the laboratory assignments, some students obtain new insights on their research projects, and will often have an opportunity for presenting their findings in some academic meetings. Meanwhile, many academic meetings in Japan, including The Japanese Association of Anatomists, often feature special sessions where undergraduate students can present their findings under the guidance of their mentors. Such initiatives led by the Dental School and the academic meetings are geared towards raising interest in research and preparing young investigators for the future.

Dental education

Dental research

Source

Cite

Citations (0)

リン酸三カルシウム(TCP)およびリン酸化プルラン(PPL)含有新規骨補填剤による新生骨誘導における組織学的解析

日本解剖学会総会・全国学術集会講演プログラム・抄録集 (2019)

Morimoto Yasuhito Tomoka Hasegawa Kyu Shisen Matsumoto Aiko Kirikoshi Akiko

Source

Cite

Citations (0)

Histochemical examination of cathepsin K, MMP1 and MMP2 in compressed periodontal ligament during orthodontic tooth movement in periostin deficient mice

Journal of Molecular Histology (2013)

Shengyu Lv Hongrui Liu Jian Cui Tomoka Hasegawa Hiromi Hongo

Periodontal fiber

Periostin

Cathepsin K

MMP1

Cathepsin L

MMP2

10.1007/s10735-013-9548-x

Cite

Citations (29)

Osteocytic Osteolysis in PTH-treated Wild-type andRankl^−/−Mice Examined by Transmission Electron Microscopy, Atomic Force Microscopy, and Isotope Microscopy

Journal of Histochemistry & Cytochemistry (2020)

Hiromi Hongo Tomoka Hasegawa Masami Saito Kanako Tsuboi Tomomaya Yamamoto

To demonstrate the ultrastructure of osteocytic osteolysis and clarify whether osteocytic osteolysis occurs independently of osteoclastic activities, we examined osteocytes and their lacunae in the femora and tibiae of 11-week-old male wild-type and Rankl −/− mice after injection of human parathyroid hormone (PTH) [1-34] (80 µg/kg/dose). Serum calcium concentration rose temporarily 1 hr after PTH administration in wild-type and Rankl −/− mice, when renal arteries and veins were ligated. After 6 hr, enlargement of osteocytic lacunae was evident in the cortical bones of wild-type and Rankl −/− mice, but not so in their metaphyses. Von Kossa staining and transmission electron microscopy showed broadly demineralized bone matrix peripheral to enlarged osteocytic lacunae, which contained fragmented collagen fibrils and islets of mineralized matrices. Nano-indentation by atomic force microscopy revealed the reduced elastic modulus of the PTH-treated osteocytic perilacunar matrix, despite the microscopic verification of mineralized matrix in that region. In addition, 44 Ca deposition was detected by isotope microscopy and calcein labeling in the eroded osteocytic lacunae of wild-type and Rankl −/− mice. Taken together, our findings suggest that osteocytes can erode the bone matrix around them and deposit minerals on their lacunar walls independently of osteoclastic activity, at least in the murine cortical bone. (J Histochem Cytochem 68: –XXX, 2020)

Osteocyte

Matrix (chemical analysis)

10.1369/0022155420961375

Cite

Citations (8)