Hideaki E. Takahashi

Trabecular minimodeling in human iliac bone

In adult human beings, remodeling creates nearly all of new bone tissue. However, Frost hypothesized that modeling can go on in trabeculae throughout life. As this hypothesis has not been verified, we looked for histologic evidence of trabecular modeling (minimodeling) during bone histomorphometry of transiliac bone biopsy specimens obtained from 34 patients (age range, 38-81 years; mean age, 58.4 years; female, 31/34) at the time of total hip arthroplasty. Before the bone biopsy study, we performed quantitative bone scintigraphy of bilateral hip joints and bilateral iliac crests in 10 other patients with unilateral hip disease and confirmed that the bone biopsy site was not affected by ipsilateral hip joint disease. Patients who had metabolic bone diseases or who had taken medications known to affect bone metabolism were excluded from the study. During modeling where bone formation and bone resorption are not coupled, bone formation can occur on quiescent bone surfaces without preceding bone resorption and create smooth cement lines. Therefore, the combination of fluorochrome labeling and a smooth cement line without interruption of surrounding collagen fibers was regarded as evidence of minimodeling. Histologic evidence of minimodeling was detected in 21 of the entire 34 specimens (62%) and 17 of 27 specimens obtained from postmenopausal patients (63%). Bone volume of minimodeling sites was less than 1% of the trabecular bone volume, and these sites accounted for less than 2% of the entire bone surface on average. However, osteoid volume of minimodeling sites comprised approximately one-tenth of the entire osteoid volume, and their labeled surface constituted one-fourth to half of the entire labeled surface on average. Therefore, when performing bone histomorphometry of adult cancellous bone, minimodeling should be taken into account when dealing with parameters related to osteoid volume and mineralization. A comparison of specimens with and without minimodeling demonstrated that the presence of minimodeling was correlated with smaller physique of patients, accelerated mineralization (as indicated by the higher mean MS/BS and MAR values and the shorter mean Omt), and higher metabolic turn-over of bone (as indicated by the higher mean BFR/BV value). Although the findings still need to be verified in a larger number of normal subjects without hip joint disease, they support Frosts hypothesis that minimodeling can continue throughout human life.

Changes of bone remodeling immediately after parathyroidectomy for secondary hyperparathyroidism

BACKGROUNDnSuccessful parathyroidectomy for secondary hyperparathyroidism alleviates bone pain and is followed by the development of hypophosphatemia and hypocalcemia, as well as an increase in bone mineral density. An increase in osteoblast surface (Ob.S/BS) is not observed several months after surgery. In this study, we investigated early bone changes at 1 week after parathyroidectomy and the mechanism underlying an increase in bone mineral density.nnnMETHODSnFourteen patients with severe secondary hyperparathyroidism underwent iliac bone biopsy before and 1 week after parathyroidectomy. Changes in histomorphometric parameters, including osteoclast surface (Oc.S/BS), eroded surface (ES/BS), erosion depth (E.De), fibrosis volume (Fb.V/TV), Ob.S/BS, osteoid volume (OV/BV), osteoid surface (OS/BS), and osteoid thickness (O.Th), were investigated. Changes in texture of mineralized bone and osteoid seams were also investigated.nnnRESULTSnOc.S/BS (P < 0.001), ES/BS (P < 0.01), and E.De (P < 0.001) decreased, but Fb.V/TV did not change at 1 week postoperatively. In particular, osteoclasts disappeared in almost all patients. Ob.S/BS (P < 0.001) increased, and cuboidal osteoblasts were proliferating on the trabecular surface where osteoclasts had existed before parathyroidectomy. As a result, newly developed osteoblasts coexisted with fibrous tissue after surgery. OV/BV (P < 0.005), OS/BS (P < 0.005), and O.Th (P < 0.005) increased, with lamellar osteoid volume showing a particular increase. Bone mineralization continued despite the low postoperative serum parathyroid hormone level.nnnCONCLUSIONnA rapid decrease in serum parathyroid hormone level after parathyroidectomy appears to suppress bone resorption, as well as cause a transient marked increase in bone formation and an increase in normal lamellar osteoid seams.

Cost-effectiveness of alendronate for the treatment of osteopenic postmenopausal women in Japan.

Many postmenopausal women have osteopenia, a condition characterized by loss of bone mineral density (BMD) that is not as severe as in osteoporosis. The objective of this study was to estimate the cost‐effectiveness of alendronate to prevent fractures in osteopenic postmenopausal women without a history of fracture in Japan. An individual simulation model was developed to predict lifetime costs and quality‐adjusted life years (QALYs) of 5 years of preventive alendronate therapy versus no preventive therapy. The risk of hip and vertebral fracture associated with age and BMD was derived from epidemiologic studies in Japan. We ran the model with different combinations of age (65, 70, and 75 years), BMD (70%, 75%, and 80% of young adult mean [YAM]), and additional clinical risk factors. For 70‐year‐old women with a BMD of 70% of the YAM having one of the following risk factors: a family history of hip fracture, high alcohol intake, or current smoking, the incremental cost‐effectiveness ratio (ICER) of alendronate was

Heterotopic ossification in the knee following encephalitis: a case report with a 10-year follow-up.

92,937,

Maximum Power During Vertical Jump and Isometric Knee Extension Torque Alter Mobility Performance: A Cross-Sectional Study of Healthy Individuals

126,251, and

Behavioral Effect of Short- and Long-Term Exercise on Motor Functional Recovery after Intracerebral Hemorrhage in Rats

129,067 per QALY, respectively. These results were sensitive to age, BMD, and number of clinical risk factors. Probabilistic sensitivity analysis for the base case showed that in the presence of one, two, and three risk factors, alendronate was cost‐effective in 0.2% to 2.6%, 13.1% to 56.1%, and 99.1% of the simulations, respectively, if society is willing to pay

Effects of Streptomycin Administration on Increases in Skeletal Muscle Fiber Permeability and Size Following Eccentric Muscle Contractions: STREPTOMYCIN ADMINISTRATION IN ECC

50,000 per QALY. Additional analysis indicated that alendronate can be a good value in osteopenic women if the 10‐year probability for a osteoporotic hip or vertebral fracture is more than 26.2%. Our results indicate that whether to treat osteopenia with alendronate should be determined on the basis of age, BMD, and number of clinical risk factors in terms of cost‐effectiveness.

Articular chondrocyte alignment in the rat after surgically induced osteoarthritis

We present a case of heterotopic ossification in the bilateral knees of a 26-year-old woman following viral encephalitis. After surgical excision, the patient was followed up for 10 years. Heterotopic ossification in knee joints associated with encephalitis has not been reported previously.

Time-dependent changes in the structure of calcified fibrocartilage in the rat Achilles tendon–bone interface with sciatic denervation

To provide reference values of muscle function (MF) and mobility performance (MP) and to clarify the effects of MF on MP.

Interprofessional Education at Niigata University of Health and Welfare

BACKGROUNDnIn this study, we investigated the effects of short- and long-term exercise on motor functional recovery following intracerebral hemorrhage (ICH) in rats.nnnMETHODSnMale Wistar rats were randomly divided into 5 experimental groups: ICH without training (ICH group), ICH with long-term exercise for 14days from the second day after surgery (ICHu202f+u202fLT group), ICH with short-term exercise for 7days from the second day after surgery (ICHu202f+u202fEST group), ICH with short-term exercise for 7days from the ninth day after surgery (ICHu202f+u202fLST group), and sham operation without training (SHAM group). ICH was induced by collagenase injection into the left striatum. Forelimb sensorimotor function was evaluated using forelimb placing and horizontal ladder tests.nnnRESULTSnIn the behavioral test, the ICHu202f+u202fLT and ICHu202f+u202fEST groups improved significantly compared with the ICH and ICHu202f+u202fLT groups. The ICHu202f+u202fLT and ICHu202f+u202fEST groups recovered motor function in an almost analogous pattern.nnnCONCLUSIONSnOur results indicated that, when exercise was started from an early phase after ICH, both short- and long-term exercises had similar benefits on motor functional recovery. However, continuous training using simple treadmill running may have limitations to motor functional recovery.