Search PubMed⌕ Search

Biomedical subjects

Hideki Yoshikawa

Publications and source records attributed to Hideki Yoshikawa.

At least 37 records · Page 2Linked to original sources
PubMed2006

Kinematics of the cervical spine in lateral bending: in vivo three-dimensional analysis.

STUDY DESIGN: Kinematics of the cervical spine during lateral bending were investigated using a novel system of three-dimensional motion analysis. OBJECTIVES: To demonstrate in vivo intervertebral coupled motions of the cervical spine during lateral bending of the neck. SUMMARY OF BACKGROUND DATA: No previous studies have successfully documented in vivo three-dimensional intervertebral motions of the cervical spine during lateral bending. METHODS: Twelve healthy volunteers underwent three-dimensional magnetic resonance imaging (MRI) of the cervical spine in 7 positions with 10 degrees increments of lateral bending. Relative motions of the cervical spine were calculated automatically by superimposing a segmented three-dimensional-MRI of the vertebra in the neutral position over images of each position using volume registration. RESULTS: Mean maximum lateral bending of the cervical spine to one side was 1.6 degrees to 5.7 degrees at each level. Coupled axial rotation opposite to lateral bending was observed in the upper cervical levels (Oc-C1, 0.2 degrees ; C1-C2, 17.1 degrees ), while in the subaxial cervical levels, it was observed in the same direction as lateral bending except for at C7-T1. Coupled flexion-extension motion was small at all vertebral levels (<1.1 degrees). CONCLUSIONS: We succeeded in identifying in vivo coupled motions of the cervical spine in lateral bending for the first time.

Adult↗
PubMed2006

Cloning and regulation of the vertebrate homologue of lin-41 that functions as a heterochronic gene in Caenorhabditis elegans.

The Caenorhabditis elegans gene lin-41 is the one of the heterochronic genes that regulate the timing of many developmental events. MicroRNA let-7 negatively regulates the expression of lin-41 through RNA-RNA interaction on its 3' untranslated region (UTR). Here, we report the isolation of chick and mouse homologues of lin-41 that encode the RBCC-NHL family protein and their expression patterns. C. elegans lin-41 is one of the RBCC-NHL families and the predicted amino acid sequences of isolated two genes encode the same family proteins. Chick and mouse lin-41 expression was also observed in developing limb buds, branchial arches, and tail buds. The 3'UTRs of the mouse and chick lin-41 genes contain multiple let-7 complementary sites. Using luciferase assay, we showed that lin-41 expression can be regulated through let-7 complementary sites.

3' Untranslated Regions↗
PubMed2006

Dual hydroxyapatite composite with porous and solid parts: experimental study using canine lumbar interbody fusion model.

Hydroxyapatite (HA) has been evaluated for use in a variety of applications in bone reconstruction surgery because of its high affinity with host bone and biocompatibility. However, because of the difficulty in combining porosity (for bone ingrowth) and strength in HA, it is generally considered inappropriate to use HA for high-load applications such as spinal interbody fusion. In the present study, we constructed a HA implant for spinal interbody fusion, composed of a dual HA composite (DHC) that combines two HA materials with different porosities: HA with 75% porosity, for bone ingrowth; and HA with 0% porosity, for load bearing. We used a canine lumbar interbody fusion model to evaluate bone conduction of the implant and its efficacy for bony fusion. Six months after the operation, DHC exhibited almost the same efficacy for bony fusion as iliac bone grafts. Moreover, pores of the porous part of the DHC were completely filled with newly formed bone and bone marrow cells. The present findings indicate that DHC is suitable for use as an implant material for spinal interbody fusion as a substitute for iliac bone grafts, which could eliminate the disadvantages associated with autograft harvesting.

Animals↗
PubMed2006

Longitudinal quantitative evaluation of lesion size change in femoral head osteonecrosis using three-dimensional magnetic resonance imaging and image registration.

It remains controversial whether some lesions of femoral head osteonecrosis regress during the natural course of the disease. With image registration, accurately matched image sets of the same subject can be acquired at different times. We applied image registration to evaluate lesion size change and assessed accuracy and usefulness compared to volume measurements and a conventional method. We also investigated whether lesions regress with this technique and with volume measurements. Baseline and 1 year minimum follow-up scans were conducted on 25 patients (31 hips) without radiological evidence of collapse. A three-dimensional (3D) spoiled gradient recalled echo sequence was used in the coronal direction (slice thickness = 2 mm; slice pitch = 1 mm). Size change was evaluated on all contiguous pairs of matched images after image registration. As a conventional method, coronal images (slice thickness = 5 mm) were reconstructed, and size change was evaluated on the five representative coronal slices. Evaluation with the conventional method identified eight lesions with apparent reduction; assessments using image registration and volume measurements identified three lesions, all within a year of initial steroid treatment and remaining at ARCO stage I at follow up. Evaluation of lesion size change using image registration was comparable to volume measurements. Inaccurate estimation of lesion size change due to mismatching of slice planes can be excluded. We demonstrated that some early lesions detected less than a year after initial steroid treatment can show size reduction with image registration as well as with volume measurements.

Adolescent↗
PubMed2006

In vivo three-dimensional motion analysis of the forearm with radioulnar synostosis treated by the Kanaya procedure.

Attempts to separate congenital radioulnar synostosis and restore forearm rotation had been disappointing until a new mobilization technique was developed by Kanaya and colleagues using free vascularized fascio-fat graft interposition. This technique provides a functional rotation arc, but postoperative forearm motion is difficult to evaluate given the inaccuracies in determining the range of motion and rotational axis using conventional x-rays or computed tomography. This study represents an attempt to analyze in vivo three-dimensional motion of the forearm with radioulnar synostosis treated by Kanaya's operation using a markerless bone registration technique. Six patients with seven postoperative forearms (six with congenital and one with posttraumatic radioulnar synostosis) underwent 3D computed tomography with the forearm in neutral, fully pronated, and fully supinated positions. Range of motion according to this method was 30 +/- 18 degrees, significantly smaller than the 82 +/- 29 degrees from manual examination. Improvements in range of motion were significantly greater in cases without dislocation of the radial head (46 +/- 13 degrees) than in cases with dislocation (19 +/- 10 degrees). Dislocation of the radial head was also significantly correlated with an abnormal axis of rotation of the forearm.

Adipose Tissue↗
PubMed2006

3D kinematic analysis of the acromioclavicular joint during arm abduction using vertically open MRI.

Many researchers have evaluated the motions of the shoulder girdle, especially scapular and humeral motion. However, few reports exist that describe motions of the acromioclavicular joint. The purpose of the present study was to analyze the 3D kinematics of the acromioclavicular joint during arm abduction using 3D MR images obtained by a vertically open MRI. Fourteen shoulders of seven volunteers were examined in seven static positions from 0 degrees to the maximum abduction in a seated position. 3D surface models of the clavicle and scapula were created, and the movements of the acromioclavicular joint from 0 degrees to each position were calculated using the volume-based registration technique. From these calculations, the translations were evaluated and the rotational motions were analyzed using the concept of the screw axis. In the anteroposterior direction, the clavicle translated most posteriorly (-1.9 +/- 1.3 mm) at 90 degrees of abduction and most anteriorly (1.6 +/- 2.7 mm) at maximum abduction. In the superoinferior direction, the clavicle translated slightly superiorly (0.9 +/- 1.9 mm). When analyzing relative motion of the scapula with respect to the clavicle, the scapula generally rotated about a specific screw axis passing through the insertions of both the acromioclavicular and the coracoclavicular ligaments on the coracoid process. The average rotation was 34.9 +/- 8.4 degrees.

Acromioclavicular Joint↗
PubMed2006

Prevalence and clinical features of Paget's disease of bone in Japan.

The present study aimed to evaluate the prevalence and clinical presentation of Paget's disease of bone (PDB) in Japan. As PDB is a very rare disease in Japan, a nationwide mail survey was conducted targeting doctors in the specialty most frequently diagnosing and treating PDB patients in Japan. First, the literature for all case reports in Japan published between January 1990 and December 2002 was reviewed to determine who was diagnosing and treating PDB in Japan. This literature review for all case reports in Japan revealed that 72.1% of cases in Japan were reported from departments of orthopedic surgery. A nationwide two-phase mail survey was conducted for the departments of orthopedic surgery of 2,320 general hospitals accredited by the Japanese Orthopaedic Association. Phase 1 involved determining how many patients with PDB were followed at each hospital. If the answer was one or more, phase 2 of the survey gathered information on the clinical presentation of current patients. The mail survey yielded a final response rate of 75.4% for phase 1 and 87.6% for phase 2. Phase 1 indicated that the prevalence of PDB in Japan is about 2.8 cases per million capita. Phase 2 revealed a slight female predominance, lower frequency of familial clustering, higher frequency of femoral fracture in the affected femur, and a higher ratio of symptomatic PDB in Japan compared with findings in countries displaying a higher prevalence of PDB. The present epidemiological study revealed that the disorder is extremely rare in Japanese individuals, and that some differences exist with regard to the clinical features of PDB between Japanese patients and patients from high-prevalence countries.

Adult↗
PubMed2006

Imatinib mesylate inhibits osteoclastogenesis and joint destruction in rats with collagen-induced arthritis (CIA).

Macrophage colony-stimulating factor (M-CSF) is a key factor for osteoclastogenesis at the bone-pannus interface in patients with rheumatoid arthritis as well as a receptor activator of NF-kappaB ligand (RANKL). Imatinib mesylate inhibits the phosphorylation of c-fms, a receptor for M-CSF. The present study investigates the effect of imatinib mesylate on joint destruction in rats with collagen-induced arthritis (CIA) and on osteoclastogenesis in vitro. Imatinib mesylate (50 or 150 mg/kg), dexamethasone, or vehicle was administered daily to CIA rats for 4 weeks from the onset of arthritis. Hind-paw swelling and body weight were measured weekly. At weeks 2 and 4, the metatarsophalangeal (MTP) joints and the ankle and subtalar joints were radiographically and histologically assessed. The effect of imatinib mesylate on osteoclast formation from rat bone marrow cells with M-CSF and soluble RANKL (sRANKL) in vitro was also examined. Radiographic assessment showed that 150 mg/kg imatinib mesylate suppressed the destruction of the MTP and the ankle and subtalar joints at week 2, and MTP joint destruction at week 4 in CIA rats, although hind-paw swelling was not suppressed. The number of TRAP-positive cells at the bone-pannus interface was significantly reduced in the group administered with 150 mg/kg imatinib mesylate compared with that given vehicle at week 4. Imatinib mesylate dose-dependently inhibited the proliferation of M-CSF-dependent osteoclast precursor cells in vitro as well as osteoclast formation induced by M-CSF and sRANKL. These findings suggest that imatinib mesylate could prevent joint destruction in patients with rheumatoid arthritis.

Animals↗
PubMed2006

Guidelines for diagnosis and management of Paget's disease of bone in Japan.

We here propose guidelines for the diagnosis and management of Paget's disease of bone (PDB) in Japan. These guidelines provide basic information on the epidemiology, pathophysiology, clinical signs and symptoms, diagnosis, indications for treatment, and available therapy, including orthopedic surgery. PDB is a chronic disorder characterized by focal abnormalities of bone turnover. The characteristic feature of PDB is excessive osteoclastic bone resorption coupled to increased and disorganized bone formation. The most common symptom of PDB is pain in involved bones. The most serious complication of PDB is malignant bone or soft-tissue tumor. PDB is uncommon in Japan; our survey in 2003 found 169 patients with PDB. The prevalence of PDB in Japan is 0.15/100 000; in patients aged 55 years or more, the proportion reaches 0.41/100 000. A careful medical history and physical examination are essential for the diagnosis. The diagnosis of PDB is based on finding the typical features on radiographs. Bone scintigraphy and measurement of serum alkaline phosphatase are sensitive means of screening for PDB. Since PDB is a rare disease in Japan, bone biopsy is quite often used to exclude bone metastases. The only evidence-based indication for treatment of PDB is pain in involved bones. In Japan, etidronate and calcitonin are approved by the Ministry of Health, Labour and Welfare for treating PDB, but currently risedronate is also under development for treating PDB in Japan. Indications for surgical intervention in PDB include unstable fractures, osteoarthritis, malignant soft-tissue tumor, osteosarcoma, and bone deformity.

Humans↗
PubMed2006

Critical role of cortactin in actin ring formation and osteoclastic bone resorption.

Tyrosine kinase c-Src plays an essential role in ruffled border formation and bone resorption in osteoclasts; however, it is unclear how c-Src controls ruffled border formation during bone resorption. To address this question, we investigated the role of cortactin, a c-Src substrate, in osteoclasts. We found that cortactin showed colocalization with c-Src and actin rings in osteoclasts. Overexpression of cortactin stimulated actin ring formation in RAW 264.7 cells. In contrast, overexpression of Csk inhibited tyrosine phosphorylation of cortactin and binding of cortactin to c-Src. More importantly, overexertion of a mutant cortactin strongly suppressed actin ring formation and bone resorbing activity in osteoclasts. Collectively, our data indicate that cortactin controls osteoclastic bone resorption by regulating actin organization.

Actins↗
PubMed2006

Comparison between hand rasping and robotic milling for stem implantation in cementless total hip arthroplasty.

We evaluated the effects of conventional hand rasping and robotic milling on the clinical and radiographic results of cementless total hip arthroplasty, with the same computed tomography (CT)-based 3-dimensional preoperative planning using a ROBODOC workstation (Integrated Surgical Systems, Davis, Calif). The robotic milling group consisted of 78 hips, and the hand-rasping group 78 hips. The radiographic findings from the preoperative planning and postoperative CT data were evaluated using the most accurate CT images reconstructed by the ROBODOC workstation. The robotic milling group showed significant superior Merle D'Aubigne hip score at 2 years. In the robotic milling group, there were no intraoperative femoral fractures, and a radiographically superior implant fit was obtained. Hand rasping had the potential to cause intraoperative femoral fractures, undersizing of the stem, unexpectedly higher vertical seating, and unexpected femoral anteversion causing inferior implant fit.

Adult↗
PubMed2006

Multidetector-CT evaluation of bone substitutes remodeling after revision hip surgery.

UNLABELLED: We evaluated remodeling of grafted bone substitutes after revision hip arthroplasty using serial examinations of multidetector-row computed tomography imaging. Ten patients (12 hips) had cementless revision surgery with grafting of beta-tricalcium phosphate granules and pastelike calcium phosphate cement in bone defects around the femoral component. At 3 weeks and 1 year postoperatively, the patients were evaluated using multidetector-row computed tomography imaging with a metal artifact minimizing protocol. New bone formation and changes in volume of beta-tricalcium phosphate and calcium phosphate cement were measured. At 1 year postoperatively, beta-tricalcium phosphate had decreased more than calcium phosphate cement. The residual volumes of calcium phosphate cement and beta-tricalcium phosphate were 78% (range, 37%-96%) and 30% (range, 10%-62%) of the initial grafted volume, respectively. The volume of the new bone that formed after absorption of beta- tricalcium phosphate was 34% (range, 11%-76%) of the initial beta-tricalcium phosphate volume. Use of cement in prior operations was an unfavorable factor in graft remodeling after revision surgery. Multidetector-row computed tomography is a promising tool for evaluating bone stock restoration of patients and influential factors of bone remodeling, and for clarifying remodeling patterns of various bone substitutes. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗
PubMed2006

Does alendronate prevent collapse in osteonecrosis of the femoral head?

UNLABELLED: Progression of collapse in osteonecrosis of the femoral head is related to the repair response, especially bone resorption around the necrotic region. A preliminary clinical study was done to determine whether systemic alendronate would prevent collapse and lead to pain relief in patients with osteonecrosis of the femoral head. Fourteen patients (20 hips) with osteonecrosis of the femoral head received daily administration of 5 mg alendronate (alendronate group) for 1 year. Eight patients (13 hips) with osteonecrosis of the femoral head did not receive alendronate (control group). All patients had measurements of biochemical markers of bone turnover at entry into the study, and the patients in the alendronate group repeated the measurements at 3 months, 6 months, and 12 months. All patients had clinical and plain radiographic examinations at entry into the study and at 3 months, 6 months, and 12 months. The alendronate group showed a greater decrease of biochemical marker of bone resorption than biochemical marker of bone formation. The alendronate group showed a lower frequency of collapse of the femoral head and reported less hip pain than the control group. Our results suggest alendronate has the potential to prevent collapse of the femoral head, even with extensive necrosis, presumably by inhibiting bone resorption in the necrotic region. LEVEL OF EVIDENCE: Therapeutic study, level II (prospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.

Adolescent↗
PubMed2006

Spontaneous regression of steroid-related osteonecrosis of the knee.

It is unknown whether lesions of steroid-related osteonecrosis of the knee increase or decrease in size during the course of the disease after diagnosis. We sought to determine whether steroid-related osteonecrosis of the knee would have spontaneous changes in size, and if so, the factors affecting the change. We performed baseline and followup (minimum of 1 year) magnetic resonance imaging scans on 30 knees of 17 patients. We then used image registration techniques to match two sets of images. Lesion size change was evaluated on all contiguous pairs of matched magnetic resonance images. Fourteen Stage 1 (preradiographic stage) knees in seven patients showed spontaneous incomplete regression without subsequent collapse. These patients had early steroid-related lesions detected within 3 years after starting steroid treatment and all showed bilateral and multifocal involvement; lesion regression occurred regardless of location. The initial size and location of the lesions and discontinuing steroid administration did not seem to affect regression. Regression can occur in some patients with early steroid-related osteonecrosis of the knee, and the time between initiation of steroid treatment and its diagnosis might be the most significant predictive factor.

Adolescent↗
PubMed2006

Indication of posterior lumbar interbody fusion for lumbar disc herniation.

OBJECTIVE: To examine whether lumbar disc herniation with massive extrusion and/or segmental instability can be an indicator for spinal fusion or not, by comparing the outcome of posterior lumbar interbody fusion (PLIF) and discectomy alone. METHODS: One hundred seventy-four patients with PLIF and 177 patients with discectomy were retrospectively analyzed. We hypothesized two criteria for fusion: massive herniation and segmental instability. The patients were divided into four groups according to our original criteria: group F-F (n = 96) consisted of the patients who fulfilled the criteria for fusion and underwent PLIF; group nF-F (n = 78) consisted of those who did not fulfill the criteria but had PLIF; group F-nF (n = 30) consisted of those who fulfilled the criteria but underwent discectomy; group nF-nF (n = 147) comprised those who did not fulfill the criteria and underwent discectomy. Each patient was evaluated clinically and radiologically at 5 years after operation. RESULTS: Groups F-F and nF-F had significantly superior results on low back pain compared with group F-nF (F-F vs F-nF, P < 0.05; nF-F vs F-nF, P < 0.01). The frequency of additional operation at the involved level was significantly higher in group F-nF (10.0%) than in group F-F (2.0%) (P < 0.05). Postoperative instability of the adjacent segment developed in 15 cases (8.6%) in groups F-F and nF-F and in 3 cases (1.7%) in groups F-nF and nF-nF (P < 0.01). CONCLUSION: Lumbar disc herniation with massive herniation or segmental instability can be well treated with PLIF.

Adult↗