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Biomedical subjects

Mikihiro Fujioka

Publications and source records attributed to Mikihiro Fujioka.

At least 19 recordsLinked to original sources
PubMed2007

Low molecular weight phenotype of Apo(a) is a risk factor of corticosteroid-induced osteonecrosis of the femoral head after renal transplant.

OBJECTIVE: Osteonecrosis of the femoral head (ONF) is a necrosis due to disruption of the blood flow. The disease often occurs in association with corticosteroid treatment. The pathology of corticosteroid-induced ONF is unclear, although abnormalities in the coagulation and fibrinolytic systems or in the lipid metabolism have been reported to be involved. We examined the relationships between development of ONF and genetic variations and plasma level of lipoprotein(a) (Lp(a)), which is closely involved in the coagulation and fibrinolytic systems and lipid metabolism. METHODS: The study population consisted of 112 renal transplant patients undergoing corticosteroid treatment. Their apolipoprotein (a) [apo(a)] isoform was determined by Western blotting, and patients were classified into low molecular weight (LMW) or high molecular weight (HMW) groups. The plasma Lp(a) level was measured. Patients were also examined for 3 single-nucleotide polymorphisms (SNP), -773 (G/A), +93 (C/T), and +121 (G/A). Relationships between these 3 genetic factors of Lp(a) and ONF development were examined using statistical methods including multivariate analysis. RESULTS: A strong relationship was observed between the apo(a) molecular weight phenotype and ONF development, with an increased risk of ONF development for the LMW group (adjusted odds ratio 5.75, 95% CI 1.76-18.74, p = 0.0038). No significant relationships were observed between ONF and plasma Lp(a) level and SNP. CONCLUSION: Apo(a) molecular weight phenotype would be a useful predictor of ONF that develops after corticosteroid treatment.

Apoprotein(a)↗
PubMed2006

Relationship between acetabular labrum evaluation by using radial magnetic resonance imaging and progressive joint space narrowing in mild hip dysplasia.

OBJECTIVE: The aim of this study was to investigate the relationship between abnormal acetabular labrum depicted by radial magnetic resonance and progressive joint space narrowing (JSN) of hip dysplasia. METHODS: Subjects were 23 joints [21 patients; mean age: 35.1 years (16-53 years)] that had acetabular dysplasia with lateral center-edge angle of Wiberg (CE angle) greater than 5 degrees and smaller than 25 degrees (mean, 16.4 degrees ), which did not show any arthrotic changes on plain radiograms and were followed up for 3 years or longer. Radial images of acetabular labrum were classified into three stages. RESULTS: Progression of JSN was not significantly related to CE angle but to progression of MRI stage (P=.006). In multivariate analysis, one rank progression of MRI stage was significantly associated with progression of JSN (adjusted OR=11.41, 95% CI: 1.51-86.24, P=.018). CONCLUSION: Our findings showed that in patients whose acetabular dysplasia has 5-25 degrees CE angle, MRI staging based on radial MRI is a better factor for prediction of progression of JSN than CE angle.

Acetabulum↗
PubMed2006

The therapeutic effects of basic fibroblast growth factor contained in gelatin hydrogel microspheres on experimental osteoarthritis in the rabbit knee.

OBJECTIVE: To investigate the therapeutic effects of basic fibroblast growth factor (bFGF) contained in gelatin hydrogel microspheres on osteoarthritis (OA) development in rabbit knee joints. METHODS: (125)I-labeled bFGF contained in gelatin hydrogel microspheres was administered to the knee joints of normal rabbits to confirm the sustained-release kinetics of bFGF in the knee joint. In addition, the expression of proteoglycan core protein messenger RNA was examined using real-time polymerase chain reaction to confirm the anabolic effects on the cartilage treated with the sustained release of bFGF. The bFGF in gelatin hydrogel microspheres was administered to the knee joint once every 3 weeks (a total of twice) from 4 weeks after anterior cruciate ligament transection (ACLT). Ten weeks after ACLT, gross morphologic and histologic examinations were performed. RESULTS: Sustained release of bFGF in the knee joint continued for >7 days and induced the anabolic effects on the cartilage. Intraarticular injections of bFGF contained in gelatin hydrogel microspheres suppressed the progression of OA in the ACLT rabbit model. CONCLUSION: Our findings demonstrated that sustained release of bFGF into the joint had therapeutic effects on OA development in a rabbit model. Our results suggest the potential feasibility of a new conservative treatment for OA.

Animals↗
PubMed2006

Age-related changes in the hemodynamics of the femoral head as evaluated by early phase of bone scintigraphy.

OBJECTIVE: The femoral head is reported to be in a markedly hypoemic state as compared with other tissues even under normal conditions, and it is therefore necessary to understand its hemodynamics to investigate the pathogenesis of hip disorders. It is known that aspects of intraosseous hemodynamics including blood flow and blood pool can be evaluated soon after radioisotope administration. In this study, hemodynamic changes in the femoral head according to gender and age were examined by investigating accumulation of radioisotope in the tissue during the early phase of bone scintigraphy. METHODS: The subjects of this study consisted of 58 joints of 31 men and 75 joints of 41 women, whose ages ranged from 15 to 87 years (average age: 67.9 years). Images of bone scintigraphy were obtained for 15 to 20 minutes at 5 minutes and at 3 hours after radioisotope administration. The ratio of accumulation in the femoral head to that in the diaphysis (head-to-diaphysis ratio, HD ratio) was calculated. RESULTS: HD ratios obtained 15-20 minutes later ranged from 0.01 to 7.35 (1.88 +/- 0.91, mean +/- SD). HD ratios decreased with age, and a significant inverse correlation was observed between age and HD ratio, demonstrating a correlation coefficient of -0.27 (p = 0.001). The HD ratio among men was 0.01-3.57 (1.66 +/- 0.71), while that among women was 0.53-7.35 (2.05 +/- 1.01), and a significant difference was observed in HD ratio between men and women (p = 0.02). There was a significant difference in HD ratios between men and women in their teens to forties (p = 0.03), while no significant differences was observed in the other age groups.. HD ratios obtained 3 hours later ranged from 0.44 to 6.32 (1.95 +/- 0.79, mean +/- SD), and no significant correlation was observed between age and HD ratio, demonstrating a correlation coefficient of -0.14. CONCLUSION: The present study demonstrated that blood flow and blood pool of the femoral head decrease with aging particularly in women. This hemodynamic deterioration of the femoral head caused by aging may have an effect on the onset and progression of hip disorders by influencing bone metabolism.

Adolescent↗
PubMed2006

Life expectancy and functional prognosis after femoral neck fractures in hemodialysis patients.

OBJECTIVES: To identify whether differences exist in the outcomes between patients undergoing hemodialysis and elderly nonhemodialysis patients with a femoral neck fracture. DESIGN: Retrospective review. SETTING: Level 1 trauma center. PATIENTS/INTERVENTIONS: A total of 71 femoral neck fractures in 62 patients undergoing hemodialysis treated nonoperatively or operatively. MAIN OUTCOME MEASUREMENTS: Clinical outcomes were analyzed to identify factors that may be correlated with life expectancy and functional prognosis. RESULTS: The overall survival rates in this study at 1-year and 5-years postfracture were found to be 89.8% and 51.5%, respectively. There were significant correlations among the survival rate, patients' age, type of treatment, prefracture ambulation status, and prefracture activities of daily living status. However, using multivariate analysis, the only significant predictor of life expectancy was prefracture ambulation status. As for functional prognosis, the rates of total ambulation recovery and total activities of daily living recovery at 1-year postfracture were 50.0% and 71.2%, respectively. Both patients' age and age at the onset of hemodialysis may contribute considerably to functional prognosis in patients undergoing hemodialysis after femoral neck fracture. CONCLUSIONS: The present study suggests that the clinical outcomes of patients with femoral neck fractures who undergo hemodialysis are considerably superior to those of previous studies. In addition, when those fractures are treated surgically with specific management in patients undergoing hemodialysis, it may be possible to expect a life expectancy and functional prognosis similar to elderly nonhemodialysis patients with hip fractures.

Adult↗
PubMed2006

Incidence of physeal injuries in Japanese children.

Although epidemiological studies on epiphyseal injury have been reported, such studies have not been made systematically in Japan. In this study, we examined the incidence of epiphyseal injury in paediatric patients treated at five general hospitals and three private clinics. We treated the patients with limb injuries between January 1992 and December 1997, and reviewed them at least 18 months after the original injuries. The original radiograms and the completed case records were classified according to age and sex of the injured children, site of the fracture, type of treatment, and its complications. Epiphyseal injuries accounted for 17.9% of all paediatric fractures. The most frequently injured epiphysis was the phalanges of hands, 21.9% of all physeal injuries. Salter-Harris type I accounted for 28.6% of physeal injuries; type II (60.9%) revealed the largest number of cases in this study, compared with type III (6.7%) and type IV (3.7%). Type V was not recognized. Most physeal injuries were treated conservatively. Either weight-bearing joints or elbow joints were treated surgically. Complications of physeal injuries were seen in seven cases. Five cases involved the upper limb, and the other two cases involve the lower limb. Although deformity or malfunction caused by physeal injuries was remained, only one case needed a corrective osteotomy. Other six cases revealed a fair prognosis.

Adolescent↗
PubMed2005

A functional single nucleotide polymorphism in the core promoter region of CALM1 is associated with hip osteoarthritis in Japanese.

Osteoarthritis (OA), a common skeletal disease, is a leading cause of disability among the elderly populations. OA is characterized by gradual loss of articular cartilage, but the etiology and pathogenesis of OA are largely unknown. Epidemiological and genetic studies have demonstrated that genetic factors play an important role in OA. To identify susceptibility genes for OA, we performed a large-scale, case-control association study using gene-based single nucleotide polymorphisms (SNPs). In two independent case-control populations, we found significant association (P=9.8x10(-7)) between hip OA and a SNP (IVS3-293C>T) located in intron 3 of the calmodulin (CaM) 1 gene (CALM1). CALM1 was expressed in cultured chondrocytes and articular cartilage, and its expression was increased in OA. Subsequent linkage-disequilibrium mapping identified five SNPs showing significant association equivalent to IVS3-293C>T. One of these (-16C>T) is located in the core promoter region of CALM1. Functional analyses indicate that the susceptibility -16T allele decreases CALM1 transcription in vitro and in vivo. Inhibition of CaM in chondrogenic cells reduced the expression of the major cartilage matrix genes Col2a1 and Agc1. These results suggest that the transcriptional level of CALM1 is associated with susceptibility for hip OA through modulation of chondrogenic activity. Our findings reveal the CALM1-mediated signaling pathway in chondrocytes as a novel potential target for treatment of OA.

Alleles↗
PubMed2005

Evaluation of the hemodynamics of the femoral head compared with the ilium, femoral neck and femoral intertrochanteric region in healthy adults: measurement with positron emission tomography (PET).

OBJECTIVE: Non-traumatic osteonecrosis of the femoral head (ONF) is considered to be a disease that occurs primarily due to ischemia of the femoral head, while its etiology and pathology are not fully understood. It is therefore necessary to identify the characteristics of the hemodynamics of the femoral head. In this study, the hemodynamics in the ilium and proximal regions of the femur, including the femoral head, was investigated using positron emission tomography (PET). METHODS: The subjects of this study consisted of 8 hip joints of four healthy male adults and 3 hip joints on the contralateral side of a femoral neck fracture, avulsion fracture of the greater trochanter and coxarthrosis (1 case each, all females) for a total of 11 hip joints of 7 subjects. The ages of the subjects ranged from 25 to 87 years (average age: 54 years). Blood flow was measured by means of the H215O dynamic study method and blood volume was measured by means of the 15O-labeled carbon monoxide bolus inhalation method. RESULTS: Blood flow was determined to be 9.1 +/- 4.8 ml/min/100 g in the ilium and among proximal regions of the femur (femoral head, neck and intertrochanteric region), 1.8 +/- 0.7 ml/min/100 g in the femoral head, 2.1 +/- 0.6 ml/min/100 g in the femoral neck, and 2.6 +/- 0.7 ml/min/100 g in the intertrochanteric region. In addition, blood volume was 4.7 +/- 1.3 ml/100 g in the ilium, and among proximal regions of the femur, 1.1 +/- 0.5 ml/100 g in the femoral head, 2.1 +/- 0.7 ml/100 g in the femoral neck, and 2.6 +/- 0.9 ml/100 g in the intertrochanteric region. The results showed that both blood flow and volume were lowest in the femoral head. Blood flow and volume were significantly lower in the proximal regions of the femur (femoral head, neck and intertrochanteric region) than in the ilium (p < 0.01). CONCLUSION: The present study demonstrated that the femoral head is in a hypoemic state as compared with other osseous tissue, indicating that even the slightest exacerbation of hemodynamics in the femoral head can trigger an ischemic condition culminating in ONF.

Adult↗
PubMed2005

Reliability of one-point blood sampling method for calculating input function in Na18F PET.

OBJECTIVE: Conventional methods of quantitative Na18F positron emission tomography require multiple arterial blood sampling in order to obtain the input function, and the procedures are invasive and complicated. This study aims to establish a simplified and reliable technique for obtaining the input function. METHODS: Multiple arterial blood sampling was performed on 12 persons. The time point for one-point sampling was determined as the time when (1) the plasma radioactivity obtained showed the highest correlation to the real integrated value, which was calculated from the input function, and (2) the coefficient of variation of the real integrated value divided by plasma radioactivity obtained at each time point became the minimum. Scaling factors were obtained in order to estimate the plasma radioactivity at each time point, and a reference table was produced in order to estimate the input function. RESULTS: The optimal timing for one-point sampling was 12 min after intravenous injection of Na18F. The estimated integrated value obtained from arterial blood sampling at 12 min and the reference table was highly correlated with the real integrated value (P<0.001). Levels of plasma radioactivity of arterial blood and venous blood were almost the same at 12 and 40 min after Na18F injection. Percentage errors in the estimation of the integrated value were 2.63% (n=12) for the arterial blood collected at 12 min and 4.14% (n=12) for the venous blood collected at 30 min. CONCLUSIONS: This simplified method is clinically applicable and would replace traditional methods that require multiple blood sampling.

Adult↗
PubMed2005

Usefulness of epiphyseal quotient measurement on magnetic resonance images for outcome prediction in patients with early-stage Legg-Calve-Perthes disease.

To investigate the usefulness of epiphyseal quotient (EQ) measurement for outcome prediction in patients with Legg-Calve-Perthes disease (LCPD), magnetic resonance (MR) imaging was performed in 26 patients with unilateral LCPD within 6 months of the disease onset and subsequently once every 3 months. All the patients were treated conservatively in our institute between 1990 and 1999. The mean follow-up period was 80 months. Clinical outcome was evaluated based on the plain radiograms of the femoral head at the final examination according to Stulberg's classification: the patients whose outcome was class I were regarded as 'excellent' (excellent group), class II as 'good' (good group), and classes III, IV and V as 'poor' (poor group). The excellent group consisted of 10 patients, the good group of 12, and the poor group of four. The EQ measured on MR images (MR-EQ) decreased remarkably in the poor group chronologically, whereas there was no decrease in the excellent group and a slow decrease in the good group. The mean MR-EQ at or before the sixth month (range, 2-6 months; mean, 4.9 months) was 86.2 (range, 76.8-94.8) in the excellent group, 78.3 (57.0-93.4) in the good group, and 67.4 (57.8-74.5) in the poor group (P<0.05 among the three groups). According to our results, because all patients having an MR-EQ at or before the sixth month of 75 or higher were classified in the excellent or good groups, it is thought that the ongoing method of treatment can be continued. On the other hand, since half of the patients having an MR-EQ at or before the sixth month of lower than 75 were classified in the poor group and had a high potential for a poor outcome, it is thought that these patients require strict containment therapy, and altering the surgical procedure could be considered depending on the particular patient. It was thought that the MR-EQ is a useful predictive factor of LCPD prognosis.

Child↗
PubMed2005

Effects of alternating current electrical stimulation on lengthening callus.

Limb lengthening by the callotasis method has been clinically applied to patients who suffered from limb length inequality, micromelia, angular deformation and partial bone defect on long bones. However, this technique was time consuming and led to various complications, such as infection at the pin insertion sites, limitation of the range of motion in adjacent joints, muscular weakness and peripheral neuroparalysis. This study was undertaken to investigate whether alternating current electric (AC) stimulation could shorten the maturation period during callotasis. The tibiae of 20 immature male Japanese white rabbits were osteotomized and fixed with external lengthener (Orthofix M100; Orthofix Srl, Bussolengo, Italy). The experimental schedule lasted 5 weeks consisting of 1 week for the latency period, 2 weeks for distraction and 2 weeks for maturation. Twenty rabbits were equally divided into two groups: the control group and the electrical stimulation (ES) group. The control group was not stimulated with an AC stimulator. The ES group was stimulated for 5 weeks just after osteotomy. The obtained results revealed radiologically, electrophysiologically and histologically that AC stimulation accelerated the maturation of lengthened callus and that it could shorten the time course of callus lengthening.

Animals↗
PubMed2004

Relationship between postrenal transplant osteonecrosis of the femoral head and gene polymorphisms related to the coagulation and fibrinolytic systems in Japanese subjects.

BACKGROUND: Nontraumatic osteonecrosis of the femoral head (ONFH) is one of the complications that may occur after renal transplantation. We investigated the relationship between the incidence of ONFH and polymorphisms in the genes for plasminogen activator inhibitor (PAI)-1, which is one of the major regulatory proteins of the fibrinolytic system, and 5,10-methylenetetrahydrofolate reductase (MTHFR), which is associated with the plasma levels of homocysteine in Japanese subjects. METHODS: Thirty-one patients with postrenal transplant ONFH and 106 patients without ONFH were selected. Genotypes of PAI-1 4G/5G and MTHFR C677T were determined by direct sequencing of genomic DNA. In addition, plasma PAI-1 antigen (Ag) levels and plasma total homocysteine (tHcy) levels at the steady state were measured. The relationships between the incidence of ONFH and these genotypes, as well as plasma levels of the gene products, were investigated. RESULTS: Plasma PAI-1 Ag levels were the highest in patients with the 4G/4G genotype, and plasma tHcy levels were the highest in patients with TT genotypes of MTHFR C677T. However, the relationship between the incidence of ONFHH and PAI-1 4G/5G or MTHFR C677T was not observed. The relationship between the incidence of ONFH and plasma levels of PAI-1 Ag or tHcy was not observed. CONCLUSIONS: Genotypes of PAI-1 4G/5G and MTHFR C677T or plasma concentrations of PAI-1 Ag and tHcy had no effect on the incidence of ONFH in Japanese subjects, unlike the results of studies performed in white subjects. The effect of genetic background on the pathologic conditions that developed in patients with postrenal transplant ONFH may differ according to race.

Adolescent↗
PubMed2004

Initial change in transient osteoporosis of the hip on magnetic resonance images: a case report.

We report the case of a 29-year-old Japanese man with transient osteoporosis of the left hip (TOH) following contralateral TOH, paying special attention to the initial changes on MRI. MR images showed no abnormal findings 6 weeks before the clinical manifestation, but the images just after the onset depicted a linear abnormality equivalent to a subchondral insufficiency fracture. Both radiological findings and clinical symptoms disappeared completely without any surgical intervention within 10 months.

Journal Article↗
PubMed2003

Minimum 10-year radiographic follow-up of a cementless acetabular component for primary total hip arthroplasty with a bulk autograft.

We radiographically investigated 36 hips in 34 patients with osteoarthritis of the hip who had undergone total hip arthroplasty. Their mean age was 59.2 years (range 36-79 years), and the mean follow-up period was 11.2 years (range 10-14 years). The long-term outcome and the chronological changes in the bulk autograft were examined. The acetabular component of the prosthesis was a Lord-type threaded cup with a smooth surface. At follow-up, bone absorption was minor in 17 joints, moderate in 11, and major in 8. The hips with graft coverage of >==20% (group A) had a significantly higher loosening rate than hips with coverage of <<20% (group B) ( P << 0.05). The cup position changed markedly in group A. Our findings indicate that graft coverage should be less than 20% when a bulk graft is used together with a smooth-surfaced cementless cup.

Acetabulum↗
PubMed2003

Risk factors for nontraumatic osteonecrosis of the femoral head after renal transplantation.

We investigated risk factors for osteonecrosis of the femoral head (ONF) in renal transplant recipients, who are susceptible to the disease. Among 287 renal transplant recipients, 18 ONF patients with enough data were included, and 18 age- and sex-matched recipients without ONF were nominated as reference cases. Risk factors were analyzed using a conditional logistic regression method. There were no differences between the ONF patients and the reference cases regarding the types of immunosuppressant or the donor (living or cadaveric, father or mother, matching blood type and human leukocyte antigens). The daily oral steroid dosage (prednisolone 25.0 mg/day or more) and blood urea nitrogen level 2 months after transplantation were the only factors with relevance to the occurrence of ONF. We propose that oral steroid dosages should be low or reduced after renal transplantation, and acute rejection should be controlled with pulsed therapy.

Adult↗
PubMed2003

Effect of heat stimulation on viability and proteoglycan metabolism of cultured chondrocytes: preliminary report.

Thermotherapy has been applied to various joint diseases and injuries, but its direct effects on articular cartilage have remained unclear. The present study examined the effects on cell viability and metabolism by using the chondrocyte-like cell line HCS-2/8. The temperatures and durations of heat stimulation were 39 degrees, 41 degrees, 43 degrees, and 45 degrees C for 15 or 30 min. After heat stimulation of 41 degrees C or lower for 15 or 30 min, cell viability increased and proteoglycan metabolism was accelerated, whereas after stimulation at 43 degrees C or higher for 30 min the viability and metabolism decreased. These results indicate that appropriate heat stimulation positively affects cell viability and the proteoglycan metabolism of articular cartilage, whereas too much heat stimulation produces negative effects. Clinical efficacy is therefore determined by the overall thermal dose. When the appropriate combination of temperature and duration is found, thermotherapy for diseases and injury of articular cartilage can be highly useful in clinical practice.

Cell Survival↗
PubMed2003

Genetic analysis of steroid-induced osteonecrosis of the femoral head.

With advanced organ transplantation technology, steroid-induced osteonecrosis of the femoral head (ONF) is one of the most troublesome complications. Steroid sensitivity varies among individuals, and the involvement of polymorphism of various genes relating to steroid metabolism is suggested. The present study investigated the relation between single nucleotide polymorphism (SNP) on the DNA sequence of cytochrome p(450) and ONF development. The subjects were 80 renal transplant patients. Genome DNA was obtained from the peripheral blood, and SNP analyses for CYP3A4, CYP2D6, and CYP2C19 were conducted using various methods: direct sequencing, polymerase chain reaction restriction fragment length polymorphism, and DNA Chip. The relation between ONF development and SNP was statistically analyzed. It is useful if the generating risk judged according to SNPs to prevention of steroid-induced ONF is possible. This time, SNPs, which are clearly related to ONF, were not accepted, although the possibility that SNP related to steroid metabolism is involved in ONF development is important. We think that it is necessary to examine this area more closely.

Aryl Hydrocarbon Hydroxylases↗