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Natsuo Yasui

Publications and source records attributed to Natsuo Yasui.

50 records · Page 3Linked to original sources
PubMed2003

The pathogenesis of slippage and deformity in the pediatric lumbar spine: a radiographic and histologic study using a new rat in vivo model.

STUDY DESIGN: Rat lumbar spines with posterior destabilizing surgery were evaluated radiographically and histologically. OBJECTIVES: To create an appropriate rat model showing the vertebral slippage and deformities frequently observed in pediatric patients with spondylolysis, and to clarify their pathogenesis. SUMMARY OF BACKGROUND DATA: There are controversial hypotheses regarding the pathogenesis of slippage and deformities of the pediatric spine with pars defects. Furthermore, there is no appropriate animal model mimicking those conditions. METHODS: After posterior destabilizing surgery, the lumbar spines of young (4-week-old) and adult (26-week-old) rats were radiographically examined at weekly intervals during 3 weeks, and histologically 3 weeks after the surgery. RESULTS: Slippage occurred in the young rats, but not in the adult rats. In the young rats, 7.2% slippage was observed 1 week after the surgery, whereas the slippage in the adult rats was 0%. The difference in percentage of slippage between the two groups was significant (P < 0.05). Lumbar deformity also was seen in the young rats, but not in the adult rats. The lumbar index of L6, as an indicator of L6 rounding, was 91.7% immediately after surgery. It had decreased to 87.7, 84.6, and 74%, respectively, 1, 2, and 3 weeks after surgery. Histologic examination showed growth plate injury in the young group and pronounced disc degeneration in the adult group. CONCLUSIONS: The young rat with posterior destabilizing surgery was an appropriate animal model, mimicking the slippage and deformities radiographically seen in pediatric patients with spondylolysis. The histologic examination indicated that vertebral growth plate impairment was the basic lesion causing such slippage and deformities in pediatric spines.

Aging↗
PubMed2003

Development of autoimmune exocrinopathy resembling Sjögren's syndrome in adoptively transferred mice with autoreactive CD4+ T cells.

OBJECTIVE: The pathologic mechanisms responsible for organ-specific tissue damage in primary Sjögren's syndrome (SS) remain unclear, but it has been suggested that the pathology is mediated by autoreactive CD4+ T cells infiltrating the salivary and lacrimal glands. This study was undertaken to investigate whether alpha-fodrin autoantigen-specific autoreactive CD4+ T cells are capable of inducing autoimmune lesions. METHODS: A total of 45 synthetic alpha-fodrin peptides designed to be 20 amino acid residues in length were generated. To establish an autoreactive T cell line, limiting dilution analysis (LDA) was performed on lymph node cells (LNCs) in the presence of alpha-fodrin peptides. The effects of adoptive transfer of autoreactive CD4+ T cells into normal syngeneic recipients were investigated. RESULTS: Autoreactive CD4+ T cell lines that recognize synthetic alpha-fodrin peptide, which produced Th1 cytokines and showed cytotoxic activities, were established in a murine model for SS. T cell receptor V(beta) usage and third complementarity-determining region (CDR3) sequences indicated that in some cases V(beta)6-CDR3 genes matched between the tissue-infiltrating T cells and the autoreactive T cell lines. Adoptive transfer of the autoreactive CD4+ T cells into normal syngeneic recipients induced autoimmune lesions quite similar to those of SS. CONCLUSION: Our data help to elucidate the pathogenic mechanisms responsible for tissue destruction in autoimmune exocrinopathy and indicate that autoreactive CD4+ T cells play a pivotal role in the development of murine SS.

Adoptive Transfer↗
PubMed2003

A new endoscopic technique to decompress lumbar nerve roots affected by spondylolysis. Technical note.

The authors describe a new endoscopic technique to decompress lumbar nerve roots affected by spondylolysis. Short-term clinical outcome was evaluated. Surgery-related indications were: 1) radiculopathy without low-back pain; 2) no spinal instability demonstrated on dynamic radiographs; and 3) age older than 40 years. Seven patients, four men and three women, fulfilled these criteria and underwent endoscopic decompressive surgery. Their mean age was 60.9 years (range 42-70 years). No subluxation was present in four patients, whereas Meyerding Grade I slippage was demonstrated in three. For endoscopic decompression, a skin incision of 16 to 18 mm in length was made, and fenestration was performed to identify the affected nerve root. The proximal stump of the ragged edge of the spondylotic lesion, and the fibrocartilaginous mass compressing the nerve root were removed. The follow-up period ranged from 6 to 22 months (mean 11.7 months). Clinical outcome was evaluated using Gill criteria; in three patients the outcome was excellent, and in four it was good. This new endoscopic technique was useful in the decompression of nerve roots affected by spondylolysis, the technique was minimally invasive, and the clinical results were acceptable.

Adult↗
PubMed2003

Electrical stimulation prevents deterioration of the oxidative capacity of disuse-atrophied muscles in rats.

INTRODUCTION: The purpose of this study was to evaluate the effects of electrical stimulation on disuse-atrophied muscles. METHODS: Sprague-Dawley rats were used and divided into three groups: control (C), hind-limb suspended for 7 d (HS), and HS plus transcutaneous electrical stimulation for 7 d (ES). In the ES group, transcutaneous electrical stimulation was induced at 1 Hz for 1 h every day to condition the gastrocnemius-plantaris-soleus muscles. Muscle oxidative capacity was evaluated by 31P-MRS in vivo. Maximum tension and muscle wet mass were also measured. RESULTS: Muscle oxidative capacity decreased within 1 wk in HS; however, it was maintained when electric stimulation was applied to the suspended limb. The maximum twitch tension in HS was significantly smaller than that in C (p < 0.05), while in ES it did not differ from that in C. The muscle mass was significantly smaller in the HS and ES groups compared to C (p < 0.05). CONCLUSION: These data indicated that twitch electrical stimulation was effective in preventing deterioration of muscle functions, such as maximum tension and oxidative capacity, induced by 1 wk of disuse.

Animals↗
PubMed2002

Mice lacking the EDB segment of fibronectin develop normally but exhibit reduced cell growth and fibronectin matrix assembly in vitro.

Fibronectins (FNs) are major cell-adhesive proteins in the extracellular matrix and are essential for embryonic development. FNs are encoded by a single gene, but heterogeneity is introduced by alternative pre-mRNA splicing. One of the alternatively spliced segments, extra domain B (EDB), is prominently expressed during embryonic development and in tumor tissues, although it is mostly eliminated from FN in normal adult tissues. To examine the function of the EDB segment in vivo, we generated mice lacking the EDB exon using the Cre-loxP system. Although EDB-containing FNs are highly expressed throughout early embryogenesis, EDB-deficient mice developed normally and were fertile. Despite the absence of any significant phenotypes observed in vivo, however, fibroblasts obtained from EDB-deficient mice grew slowly in vitro and deposited less FN in the pericellular matrix than fibroblasts from wild-type mice. These results indicate that expression of EDB-containing isoforms is dispensable during embryonic development, yet may play a modulating role in the growth of connective tissue cells via the FN matrix.

Amino Acid Sequence↗
PubMed2002

Multiple trigger fingers associated with geleophysic dysplasia.

We report an infant with geleophysic dysplasia (MIM 231050) who developed multiple trigger fingers. The condition was progressive and distinct from trigger thumb, which is generally seen in infants without any underlying metabolic disease.

Abnormalities, Multiple↗
PubMed2002

Cyclooxygenase-2 inhibitor inhibits the fracture healing.

We investigated the effects of cyclooxigenase-2 (cox-2) on fracture healing. After closed non-displaced fractures were created at the middle of both femoral shafts in 12-week-old Wister rats, a cox-2 specific inhibitor, etodolac (20 mg/day; intra-peritoneal) was administered every day for three weeks (E group). Bone union and callus formation were evaluated by weekly radiographs. Three weeks after surgery, the mechanical strength of the fractured femur was evaluated by a three-point-bending test. These results were compared with those of a vehicle control group (V group). The fracture healing score on radiographs in the E group three weeks after the surgery was 3.3 +/- 0.9, and in the V group it was 5.8 +/- 1.5, indicating that fracture healing was significantly poorer in the E than the V group (p < 0.05). From the three point bending test, the ultimate strength and stiffness of etodolac-treated fractured femurs were shown to be significantly lower than those in vehicle control group (p < 0.05). Mechanically, femurs of etodolac treated rats were weaker than those of control rats. Thus, it was concluded that etodolac, a cox-2 specific inhibitor, inhibited fracture healing.

Animals↗
PubMed2002

Effects of constitution, atraumatic vertebral fracture and aging on bone mineral density and soft tissue composition in women.

Constitution, atraumatic vertebral fracture and aging affect bone mineral density (BMD) and soft tissue composition. The high body weight of obese women involves a high mechanical load being exerted on weight bearing bones compared with thin women, which probably contributes to their higher BMD and the lower incidence of fractures in obese women compared with thin women. Atraumatic vertebral fracture (AVF) is a typical osteoporotic fracture and its favorite site of AVF is the vertebral bodies of the thoracolumbar region. The BMD of weight bearing bones is lower in patients with AVF than in patients without AVF, whereas there is no significant difference in soft tissue composition between the two. The regional and total BMD decrease with advancing age. The magnitude of the decrease in lumbar and thoracic BMD is high compared with other regional BMD, and total fat mass and total lean mass decline with age to their respective minimal level. The high rate of decrease in lumbar and thoracic BMD appears to be due to the high content of trabecular bone compared with other regional bones.

Aging↗
PubMed2002

Intergenerational comparison of total and regional bone mineral density and soft tissue composition in Japanese women without vertebral fractures.

We measured total and regional bone mineral density (BMD) and soft tissue mass in 115 healthy Japanese women without vertebral fractures. The subjects, aged 20 to 75 years, were divided into four age groups: 20's to 40's group (n=33), 50's group (n=26), 60's group (n=26), and 70's group (n=30). BMD was measured by dual energy X-ray absorptiometry (DXA). The evaluated regions were the head, arms, legs, ribs, thoracic vertebrae, lumbar vertebrae and pelvis. The total and regional BMDs were the highest in the 20's to 40's group, and they decreased with age, and reached their respective lowest values in the 70's group. The decrease in BMDs of the spine and pelvis was the most prominent of all regional BMDs. Total and regional lean mass and fat mass were the highest in the 20's to 40's group, and they decreased to their respective lowest values in the 70's group. The results showed that the decrease in BMD of the spine and pelvis was the most prominent of all regional BMDs associated with a decrease in the total and regional lean mass and total and regional fat mass.

Absorptiometry, Photon↗
PubMedDate not supplied

Treatment of relapsed idiopathic clubfoot by complete subtalar release combined with the Ilizarov method.

This study presents the clinical and radiographic outcomes of 6 feet (4 patients) with relapsed idiopathic clubfoot that were treated with a combination of subtalar release and the Ilizarov method. The mean patient age at the time of the surgery was 7.4 years (range, 4.5-10.5 years), and the mean follow-up was 5.1 years (range, 2.0-7.3 years). All cases achieved a plantigrade foot, better walking ability, and parental satisfaction with the result. Ankle joint range of motion increased from a mean of 17 degrees (range, 10-30 degrees) preoperatively to 45 degrees (range, 35-65 degrees) at final follow-up. The talocalcaneal angle improved from a mean of 26 degrees (range, 15-34 degrees) preoperatively to 55 degrees (range, 47-65 degrees) at follow-up. The mean tibiocalcaneal angle improved from 95 degrees (range, 87-115 degrees) preoperatively to 80 degrees (77-83 degrees) at follow-up, whereas the talometatarsal angle improved from a preoperative mean of -19 degrees (range, -35 to -10 degrees) to 3.5 degrees (range, -5 to 7 degrees) at follow-up. Recurrence was observed in only 1 foot with forefoot adductus, caused by a pin tract infection and early fixator removal. These cases suggest the Ilizarov method combined with subtalar release are beneficial for the treatment of relapsed idiopathic clubfoot.

Child↗
PubMedDate not supplied

Differential expression of VEGF isoforms and VEGF receptors in cartilaginous tumors.

Vascular endothelial growth factor (VEGF), which is known to have at least five isoforms and four receptors, is integral to tumor-induced neovascularization. In order to determine whether VEGF signaling is modulated in the development of cartilaginous tumors, we analyzed osteochondrogenic tumors for the expression of VEGF isoforms and VEGF receptors using the reverse transcription-polymerase chain reaction method. Although mRNA for VEGF121, VEGF165, VEGFR-1 and NRP-2 was widely expressed, mRNA expression for VEGF189, VEGFR-2 and NRP-1 was linked to a malignant phenotype such as local invasion. These results indicated that VEGF signaling was fine-tuned by the differential expression of the VEGF isoforms and VEGF receptors.

Bone Neoplasms↗
PubMedDate not supplied

MRI characteristics of parosteal lipomas associated with the HMGA2-LPP fusion gene.

BACKGROUND: The magnetic resonance (MR) characteristics of parosteal lipomas with the HMGA2-LPP fusion transcripts are described. PATIENTS AND METHODS: The expression of HMGA2-LPP fusion transcripts was determined using the reverse transcription-polymerase chain reaction method. RESULTS: MR images of two cases with the fusion transcripts, a 56-year-old man and a 50-year-old woman, revealed heterogeneous high signal intensities on T1- and T2-weighted images, showing heterogeneous curvilinear enhancement on fat-suppressed T1-weighted images after Gd-DTPA injection, which resembled those of well-differentiated liposarcomas. CONCLUSION: Since the HMGA2-LPP fusion transcripts are exclusively detectable in benign mesenchymal tumors, testing HMGA2-LPP expression may be useful for differential diagnosis in cases of radiologically-suspected well-differentiated liposarcomas.

Female↗