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Nishi-Tokyo-shi, Japan

Kimura-Suda H.,Chitose Institute of Science and Technology | Kuwahara M.,Kureha Corporation | Hidaka K.,Chitose Institute of Science and Technology | Kanazawa K.,Chitose Institute of Science and Technology | And 7 more authors.
Molecular Crystals and Liquid Crystals | Year: 2012

End stage kidney disease (ESKD) patients are characterized to reduce bone strength due to disordering of calcium and phosphorous homeostasis. We demonstrate the use of Fourier transform infrared imaging and Raman spectroscopy to characterize bone quality in ESKD rats. Eleven-week male rats treated 5/6-nephrectomy and sham-operated rats were kept for 16 weeks, and then each femur was removed for measurements. We observe excess bone resorption compared to bone formation in ESKD rat, and bone mineral loss in endosteum is observed rather than in periosteum. We also find trabecular bone and epiphysis have a rapid turnover rate compared to cortical bone. © 2012 Taylor & Francis Group, LLC.

The bone histomorphometry is well-known as the histological evaluation method for the investigation of the efficacy of various kinds of medicine on bone metabolism disorder. Recently, in addition, it is indispensable for bone researchers to clarify characteristic of bone metabolism in genetically-modified mice by means of bone histomorphometry. Thus, bone histomorphometry has broad utility. However, it would not be an exaggeration to say that researchers are interested in only numerical value of various kinds of parameters without understanding lots of information obtained from morphological observation. Especially, we have to pay attention to measurement and interpretation of parameters of bone histomorphometry in case of growing bone, because growing bone is changing its size of longitudinal and width. In this review, we would like to explain how to measure with bone histomorphometry for modeling bone in growing animals.

Iwasaki Y.,Oita University of Nursing and Health Sciences | Kazama J.J.,Niigata University | Yamato H.,Kureha Corporation | Yamato H.,Kureha Special Laboratory Co. | Fukagawa M.,Tokai University
Bone | Year: 2011

Bone fragility is a complication of chronic kidney disease (CKD). Patients on dialysis have higher risk of fracture than the general population, but the reason remains obscure. Bone strength is determined by bone mass and bone quality. Although factors affecting bone quality include microarchitecture, remodeling activity, mineral content, and collagen composition, it remains unclear which factor is critically important for bone strength in CKD. We conducted an in vivo study to elucidate the factors that reduce bone mechanical property in CKD. Rats underwent thyroparathyroidectomy and progressive partial nephrectomy (TPTx-Nx). Bone mechanical property, bone mineral density (BMD), and cortical bone chemical composition (all in femur) as well as histomorphometry (in tibia) were determined. The storage modulus, which is a mechanical factor, was reduced in CKD model rats compared with controls that underwent thyroparathyroidectomy alone (TPTx). There were no differences in BMD and histomorphometric parameters between groups. However, cortical bone chemical composition differed: mineral to matrix ratio and carbonate substitution increased whereas crystallinity decreased in TPTx-Nx. In addition, enzymatic crosslinks ratio and pentosidine to matrix ratio also increased. These changes were significant in TPTx-Nx rats with most impaired renal function. Stepwise multiple regression analysis identified mature to immature crosslink ratio and crystallinity as independent contributors to storage modulus. Deteriorated bone mechanical properties in CKD may be caused by changes in chemical composition of the cortical bone, and is independent of BMD or cancellous bone microarchitecture. © 2011 Elsevier Inc.

Miyagawa K.,Kanagawa Dental College | Miyagawa K.,Research Institute for Maternal and Child Health | Kozai Y.,Kanagawa Dental College | Ito Y.,Yokohama Training Center | And 9 more authors.
Journal of Bone and Mineral Metabolism | Year: 2011

Our goal in this study was to determine to what extent the physiologic consequences of ovariectomy (OVX) in bones are exacerbated by a lack of daily activity such as walking. We forced 14-week-old female rats to be inactive for 15 weeks with a unique experimental system that prevents standing and walking while allowing other movements. Tibiae, femora, and 4th lumbar vertebrae were analyzed by peripheral quantitative computed tomography (pQCT), microfocused X-ray computed tomography (micro-CT), histology, histomorphometry, Raman spectroscopy, and the three-point bending test. Contrary to our expectation, the exacerbation was very much limited to the cancellous bone parameters. Parameters of femur and tibia cortical bone were affected by the forced inactivity but not by OVX: (1) cross-sectional moment of inertia was significantly smaller in Sham-Inactive rat bones than that of their walking counterparts; (2) the number of sclerostinpositive osteocytes per unit cross-sectional area was larger in Sham-Inactive rat bones than in Sham-Walking rat bones; and (3) material properties such as ultimate stress of inactive rat tibia was lower than that of their walking counterparts. Of note, the additive effect of inactivity and OVX was seen only in a few parameters, such as the cancellous bone mineral density of the lumbar vertebrae and the structural parameters of cancellous bone in the lumbar vertebrae/tibiae. It is concluded that the lack of daily activity is detrimental to the strength and quality of cortical bone in the femur and tibia of rats, while lack of estrogen is not. Our inactive rat model, with the older rats, will aid the study of postmenopausal osteoporosis, the etiology of which may be both hormonal and mechanical. © The Japanese Society for Bone and Mineral Research and Springer 2011.

Matsumoto N.,Kureha Special Laboratory Co. | Matsumoto N.,Tokushima University | Hemmi A.,Nihon University | Yamato H.,Kureha Special Laboratory Co. | And 4 more authors.
Journal of Medical Investigation | Year: 2010

The "in vivo cryotechnique" (IVCT) is a new method of morphological analysis which has the advantage of freezing tissues in living animals without stopping their blood circulation. The purpose of this study was to investigate the effect of parathyroid hormone (PTH) on renal type II Na-Pi transporters (NaPi-IIa and NaPi-IIc) and "cryobiopsy" (CB) using special cryoforceps as a simple method of the IVCT. The kidney tissues were biopsied at various time points after PTH administration by CB using liquid nitrogen as the cryogen. By hematoxylin-eosin (HE) staining the kidney tissues, well-frozen areas without visible ice crystals were obtained in the tissue surface areas, and the brush border membrane (BBM) of proximal tubules was well preserved at a light microscopic level. Immunohistochemical evaluation showed that PTH downregulated NaPi-IIa and NaPi-IIc at the BBM, being controlled by a different mechanism. In this method, the PTH-induced internalization of NaPi-IIc from microvilli to subapical compartments was not observed in the tissue preparations. NaPi-IIc protein appears to be degraded in microvilli of the proximal tubular cells after the injection of PTH. We suggest that CB using liquid nitrogen is useful to investigate renal type II Na-Pi transporters at the light microscopic level.

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