Publications by authors named "Azusa Seki"

Boron neutron capture therapy (BNCT) with p-boronophenylalanine (BPA) is expected to have less effect on the decrease in normal bone strength than X-ray therapy. However, the compound biological effectiveness (CBE) value necessary to convert the boron neutron capture reaction (BNCR) dose into a bioequivalent X-ray dose has not been determined yet. The purpose of this study was to evaluate the influence of BNCT on normal bone in mice and to elucidate the CBE factor.

View Article and Find Full Text PDF

Osteocytes, osteoblasts (bone-forming cells), and osteoclasts (bone-resorbing cells) are the primary types of cells that regulate bone metabolism in mammals. Sclerostin produced in bone cells activates osteoclasts, inhibiting bone formation; excess production of sclerostin, therefore, leads to the loss of bone mass. Fish scales have been reported to have morphological and functional similarities to mammalian bones, making them a useful experimental system for analyzing vertebrate bone metabolism in vitro.

View Article and Find Full Text PDF

Melatonin has recently been found to be a possible new regulator of bone metabolism. However, the influence of melatonin in natural age-related osteoporosis has not been fully elucidated yet, although there have been some reports regarding postmenopausal osteoporosis with melatonin treatments. The present study investigated the effects of long-term melatonin administration during the aging process on bone metabolism.

View Article and Find Full Text PDF

The following articles have been retracted by the Editorial Board of Experimental Animals, because some parts of their contents were published elsewhere.

View Article and Find Full Text PDF
Article Synopsis
  • * The study used goldfish scales to investigate how melatonin affects bone metabolism in microgravity, finding that melatonin can suppress osteoclast (bone-resorbing cells) activity.
  • * Melatonin increased the expression of Calcitonin (which inhibits osteoclasts) and decreased the factors that promote osteoclast formation, suggesting its potential as a drug to prevent bone loss in astronauts during space missions.
View Article and Find Full Text PDF

The following articles have been retracted by the Editorial Board of Experimental Animals, because some parts of their contents were published elsewhere.

View Article and Find Full Text PDF

The following articles have been retracted by the Editorial Board of Experimental Animals, because some parts of their contents were published elsewhere.

View Article and Find Full Text PDF

The effects of low-intensity pulsed ultrasound (LIPUS) on osteoclastogenesis were examined using fish scales that had both osteoclasts and osteoblasts. The binding of the receptor activator of NF-κB ligand (RANKL) in osteoblasts to the receptor activator of NF-κB (RANK) in osteoclasts induced osteoclastogenesis. Therefore, we focused on RANK/RANKL signaling.

View Article and Find Full Text PDF

Calcium phosphate cements (CPCs), consisting of a mixture of calcium phosphate powders and setting liquid, have been widely used in orthopedic applications. One of the drawbacks of CPCs is their poor resorbability in the living body, which hinders substitution with natural bones. One of the strategies to facilitate the resorption of CPCs is the incorporation of bioresorbable or water-soluble pore-generating particles (porogens), such as gelatin, in the CPC matrices.

View Article and Find Full Text PDF

Teriparatide (TPTD) is known to increase the cortical thickness and porosity. The purpose of the present study was to determine whether switching from TPTD to ibandronate (IBN) would be useful for improving cortical bone parameters as assessed using high-resolution quantitative computed tomography (HR-QCT) analyses in mature rabbits. Forty-two female New Zealand white rabbits (18-22 weeks old) were randomized into six groups of 7 animals each as follows: 4-week vehicle administration group, 4-week TPTD administration group (20 μg/kg, subcutaneously [s.

View Article and Find Full Text PDF

Bazedoxifene (BZA) is used for the treatment of post-menopausal osteoporosis. To elucidate changes in collagen, mineralization, and structural properties and their relationship to bone strength after treatment with BZA in ovariectomized (OVX) monkeys, the levels of collagen and enzymatic immature, mature, and non-enzymatic cross-links were simultaneously examined, as well as trabecular architecture and mineralization of vertebrae. Adult female cynomolgus monkeys were divided into 4 groups (n=18 each) as follows: Sham group, OVX group, and OVX monkeys given either 0.

View Article and Find Full Text PDF

This study investigated the effects of combined teriparatide (an anabolic agent) and monthly risedronate (an anti-resorptive agent) therapy on cancellous bone mass in orchidectomized (ORX) rats. Fifty 14-week-old male Sprague-Dawley rats were randomized into five groups of ten animals each: sham-operation + vehicle; ORX + vehicle; ORX + risedronate (90 μg/kg subcutaneous, every 4 weeks); ORX + teriparatide (30 μg/kg subcutaneous, three times per week); and ORX + risedronate + teriparatide. After the 12-week experimental period, cancellous bone in the tibial proximal metaphysis was examined by static and dynamic histomorphometric analyses.

View Article and Find Full Text PDF

Rats with dwarfism accompanied by skeletal abnormalities, such as shortness of the limbs, tail, and body (dwarf rats), emerged in a Jcl-derived Sprague-Dawley rat colony maintained at the Institute for Animal Experimentation, St. Marianna University Graduate School of Medicine. Since the dwarfism was assumed to be due to a genetic mutation based on its frequency, we bred the dwarf rats and investigated their characteristics in order to identify the causative factors of their phenotypes and whether they could be used as a human disease model.

View Article and Find Full Text PDF

High-dose glucocorticoids reduce cortical bone gain in rats. The aim of the present study was to examine the effect of the intermittent administration of human parathyroid hormone (1-34) (hPTH[1-34]) on cortical bone in rats treated with high-dose prednisolone (PSL). Twenty-five female Sprague-Dawley rats (6 weeks old) were randomized into the following three groups: a vehicle administration (control) group, a PSL (10 mg/kg s.

View Article and Find Full Text PDF

The purpose of the present study was to determine whether teriparatide and monthly minodronic acid would have an additive effect on cancellous bone mass in ovariectomized rats. Seven-week-old female Sprague-Dawley rats were randomized into five groups of 10 animals each, including a sham-operation+vehicle group, an ovariectomy (OVX)+vehicle group, an OVX+minodronic acid (6 μg/kgs.c.

View Article and Find Full Text PDF

Various techniques for forming TiO(2) coatings on Ti have been investigated for the improvement of the osteoconductivity of Ti implants. However, it is not clear how the oxidizing process affects this osteoconductivity. In this study, TiO(2) coatings were prepared using the following three processes: anodizing in 0.

View Article and Find Full Text PDF

Renal insufficiency induces cortical bone loss in rats. The present study examined the influence of vitamin K(2) on renal function, cortical bone mass, and bone strength in rats with renal insufficiency. Thirty male Sprague-Dawley rats (8 weeks old) were randomized by the stratified weight method to the following three groups of 10 animals each: sham operation (control), 5/6 nephrectomy, and 5/6 nephrectomy + oral vitamin K(2) (menaquinone-4, menatetrenone, 30 mg/kg, 5 days/week).

View Article and Find Full Text PDF

The present study examined changes of cancellous and cortical bone in rats with combined methionine-choline deficiency (MCD). In addition, the effects of vitamin K2 on cortical and cancellous bone mass and hepatic lipids were investigated in rats with MCD. Six-week-old male Sprague-Dawley rats were randomized into three groups of ten, including an age-matched control (standard diet) group, an MCD diet group, and an MCD diet+vitamin K2 (menatetrenone at 30mg/kg/d orally, 5 times a week) group.

View Article and Find Full Text PDF

The purpose of the present study was to examine the effect of vitamin K₂ on cancellous and cortical bone mass in rats with streptozotocin (STZ)-induced type 1 diabetes. Twenty-seven male Sprague-Dawley rats aged 12 weeks were randomized by the weight-stratified method into the following three groups: age-matched control group, STZ + vehicle group, and STZ + vitamin K₂ group. STZ (40 + 50 mg/kg) was administered intravenously twice during the initial 1-week period.

View Article and Find Full Text PDF

Red ginger (Zingiber officinale var. Rubra) has been prescribed as an analgesic for arthritis pain in Indonesian traditional medicine. The surface color of the rhizome is purple because of the anthocyanidins in its peel.

View Article and Find Full Text PDF

The purpose of the present preclinical study was to determine whether vitamin K(2) would promote bone healing in a rat femoral osteotomy model with or without glucocorticoid (GC) treatment. Thirty-eight 6 week-old female Sprague-Dawley rats underwent a unilateral osteotomy of the femoral diaphysis followed by intramedullary wire fixation and then were randomized into four groups that received the following treatment schedules: vehicle, vitamin K(2), GC + vehicle, and GC + vitamin K(2). GC (prednisolone, 2.

View Article and Find Full Text PDF

Purpose: To examine the influence of ovariectomy (OVX) on bone turnover and trabecular bone mass at the 3 clinically important skeletal sites in mature cynomolgus monkeys.

Materials And Methods: Six female cynomolgus monkeys, aged 17-21 years, were randomized into 2 groups by the stratified weight: the OVX and sham-operation groups (n = 3 in each group). The experimental period was 16 months.

View Article and Find Full Text PDF

We investigated the effect of eel calcitonin (elcatonin) on the process of fracture repair in the osteotomized femur of cynomolgus monkeys, since they possess a Haversian remodeling system similar to that of humans. Alendronate was used for comparison. Twenty female cynomolgus monkeys (Macaca fascicularis), aged 18-22 years, were allocated into five groups: control (CNT, n = 4), low-dose elcatonin group (0.

View Article and Find Full Text PDF

The purpose of the present study was to examine the effects of combined administration of alfacalcidol (ALF) and risedronate (RIS) on cancellous and cortical bone mass of the tibia in glucocorticoid (GC)-treated young rats. One hundred and nine female Sprague-Dawley rats, 3 months of age, were randomly divided by the stratified weight method into eleven groups according to the following treatment schedule: baseline control, a 4-week age-matched control, and a 4-week GC administration with a 4-week concomitant administration of vehicle, ALF, RIS, or ALF+RIS, and an 8-week age-matched control and 8-week GC administration with a 4-week administration of vehicle, ALF, RIS, or ALF+RIS that was initiated after a 4-week administration of GC. The GC (methylprednisolone sodium succinate, 5.

View Article and Find Full Text PDF

Several reports indicate that melatonin is involved in the regulation of bone metabolism. To examine the direct effect of melatonin on osteoclasts and osteoblasts, we developed an in vitro assay using fish scales that contain osteoclasts, osteoblasts, and bone matrix, all of which are similar to those found in mammalian membrane bone. Using the assay, we demonstrated that melatonin suppressed osteoclastic and osteoblastic activities.

View Article and Find Full Text PDF