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Biomedical subjects

Hisashi Iwata

Publications and source records attributed to Hisashi Iwata.

At least 19 recordsLinked to original sources
PubMed2006

Measurement of the cervical spinal cord volume on MRI.

BACKGROUND: There are some reports about the relationships between the clinical manifestations and the spine morphology or spinal cord morphology in patients with myelopathy. It has also been reported that there are interindividual variations in the cross-sectional area of the spinal cord. In most of these reports, the cross-sectional area, compression ratio, and anteroposterior diameter were used as morphologic parameters of the spinal cord, but no reports have been published on the use of spinal cord volume. OBJECTIVES: To measure the cervical spinal cord volume of healthy people and to evaluate the relationships between this volume and each of height, body weight, age, and gender, in a morphologic study of cervical spinal cord on magnetic resonance imaging (MRI). METHODS: The cervical spinal cord volume of 90 healthy people (47 males, 43 females) was measured on MRI, and the relationships between this volume and each of gender, height, body weight, and age were evaluated. In addition, the cervical spinal cord volume ratio was evaluated. RESULTS: Our study showed that in healthy people, the cervical spinal cord volume depended on the gender, age, height, and body weight and that the cervical spinal cord volume was larger in the males than in the females, decreased with age, and increased with height and body weight. However, the cervical spinal cord volume ratio was not affected by gender, age, height, or body weight. CONCLUSIONS: We consider that the cervical spinal cord volume ratio can be used to evaluate cervical spinal cord atrophy in patients with cervical myelopathy and can be important information in looking for clinically critical points. The cervical spinal cord volume was larger in males than in the females, decreased with age, and increased with height and body weight. The cervical spinal cord volume ratio was not affected by gender, age, height, or body weight.

Adolescent↗
PubMed2005

Surgical outcome of elephant-trunk anastomosis between the left carotid and subclavian arteries in aortic arch repair including the postoperative physical status of the left arm.

We studied the outcome of our modified aortic arch replacement procedure in which the distal end of the graft is anastomosed between the left common carotid artery and the left subclavian artery including the postoperative physical status of the left arm in comparison with the conventional technique. We assessed the surgical outcome of 26 patients who underwent our new technique and 11 patients who underwent the conventional one. Postoperative clinical symptoms and physical status of the left arm were also evaluated. No operative deaths were observed in the new technique group and one operative death was observed in the conventional group (9.1%). No significant differences between the two groups in postoperative clinical symptoms and the physical status of the left arm were observed. Our "distal anastomosis to the proximal level of the left subclavian artery" technique made aortic arch replacement easier and steadier with a satisfactory surgical outcome in comparison with the conventional method. The postoperative clinical symptoms and physical status of the left arm in the new technique group were identical to those in the conventional group.

Aged↗
PubMed2005

Sonoporation with doxorubicin enhances suppression of intimal hyperplasia in a vein graft model.

BACKGROUND: The purpose of the present study is to examine whether sonoporation with doxorubicin enhances suppression of intimal hyperplasia (IH) in a vein graft model. MATERIALS AND METHODS: After the administration of 1.5 mg/kg doxorubicin intravenously, the right external jugular vein of six rabbits was exposed at 2 W/cm2 and 1 MHz of ultrasound for 2 min (Sonoporation group). Tissue doxorubicin concentration was measured. In 48 rabbits, the right common carotid artery was ligated after performing a vein graft bypass. The animals were divided into the following four groups: the C0 group (surgical procedure only); the C0S (sonoporation without doxorubicin); the C1 (doxorubicin administration only); the C1S (sonoporation with doxorubicin). Twenty-four grafts were subjected to Elastic van Gieson staining for morphometric analysis 4 weeks after the operation; others were subjected to TdT-mediated X-dUTP nick end-labeling for detection of apoptic cells and to staining with a monoclonal antibody against the proliferating cell nuclear antigen for assessment of cell proliferation 1 week after. RESULTS: The tissue doxorubicin concentration was significantly higher in the Sonoporation group than in the Control group. Compared with the C0 group, IH was not suppressed in the C1 group but was significantly suppressed in the C1S group. Sonoporation with doxorubicin administration suppressed IH significantly (C1 group versusC1S group: P < 0.05). Cell apoptosis was induced and cell proliferation was suppressed significantly in the C1S group. CONCLUSIONS: Sonoporation with doxorubicin suppressed IH of the vein graft. Sonoporation may be effective in coronary or peripheral revascularization using vein grafts.

Anastomosis, Surgical↗
PubMed2005

Neurogenic tumors of the mediastinum and chest wall: MR imaging appearance.

Various histologic types of neurogenic tumors may originate in the mediastinum and chest wall. It is possible to make accurate diagnosis of these tumors by using the multiplanar capability and high contrast resolution of MR imaging because of these characteristic imaging findings. MR and histologic features of these tumors are illustrated and described in this essay.

Diagnosis, Differential↗
PubMed2004

Spontaneous healing process of a supraspinatus tendon tear in rabbits.

INTRODUCTION: The rotator cuff has a characteristic structure, in that one surface faces articular cartilage and another faces bursa. This structure may produce differences in the healing process between the rotator cuff and other tendons. We investigated the spontaneous healing process of a surgically created supraspinatus tendon tear in rabbits. MATERIALS AND METHODS: A transverse, full-thickness tear of the supraspinatus tendon was created and its healing examined. RESULTS: A tear of 12 mm was not repaired within 3 weeks. With a tear of 5 mm, reparative tissue gradually encroached into the defect from the bursal side, and the tear united from the bursal side to the articular side by 12 weeks. The healing rates (width of reparative tissue/width of the tendon x 100%) were 32.2%, 52.4%, 58.0%, 88.9%, and 93.8% at 1, 2, 3, 6, and 12 weeks, respectively. The reparative tissue had continuity to the epitenon of the bursal side. Immunohistochemical study showed that at week 1, type III collagen was detected in the reparative tissue and the cutting ends, and the expression gradually decreased. On the other hand, the expression of type I collagen in the reparative tissue was weak at week 1 and increased until week 3. PCNA-positive cells were observed in the reparative tissue. CONCLUSION: These results show that the origin of the reparative tissue is the epitenon, and from the bursal side rather than the articular side. This model is very useful for the investigation of the remodeling process of an acute rotator cuff tear.

Animals↗
PubMed2004

Primary peritonitis associated with streptococcal toxic shock-like syndrome: report of a case.

Several reports over the past 15 years describe severe group A streptococcal infections causing septic shock, soft-tissue necrosis, and multiple organ failure; a phenomenon known as streptococcal toxic shock-like syndrome (TSLS). However, primary peritonitis associated with TSLS is rare. We report the case of a 40-year-old man admitted with pain in both thighs, hypotension, and severe abdominal pain. His daughter had been diagnosed with streptococcal pharyngitis 3 days earlier. We performed an emergency laparotomy for peritonitis, and culture of the ascites was positive for group A beta -hemolytic streptococcus (GAS). Further serotyping of the isolated GAS strain revealed the T-type 22 and the pyrogenic exotoxin gene, spe-C. The criteria for TSLS were clearly met, including the isolation of GAS from ascites, hypotension, liver failure, renal failure, coagulopathy, myositis, and a generalized erythematous macular rash with desquamation.

Acute Disease↗
PubMed2004

Translocation of Salmonella typhimurium in rats on total parenteral nutrition correlates with changes in intestinal morphology and mucus gel.

OBJECTIVE: We tested whether alterations in intestinal morphology and mucus gel correlate with differences in Salmonella typhimurium translocation between rats treated with total parenteral nutrition (TPN) and rats given a diet of chow. METHODS: Twenty-seven male Wistar rats were assigned to one of two groups: one received TPN for 14 d and the other (control) received standard rat chow and water ad libitum. Salmonella typhimurium (5 x 10(8) cells; GIFU 12142) was injected into a closed ileal loop. Portal venous blood (PVB), inferior vena cava blood (IVCB), and mesenteric lymph nodes (MLNs) were sampled for evaluation of bacterial translocation. Sections of the loop were prepared and stained with hematoxylin and eosin, periodic acid-Schiff (PAS), and fluorescein isothiocyanate-labeled Ulex europaeus agglutinin I (FITC-UEA-I) for image analysis. Perimeter, mucosal thickness, villus area, and positively stained mucus area were measured. A fluorescent antibody study was also done. RESULTS: Organisms were found in cultures of 1 in 13 control rats and 9 in 14 TPN rats. There were more bacteria in MLNs than in PVB or IVCB. There was no increase in the number of bacteria over time in PVB, IVCB, or MLNs. Perimeter and villus area (P < 0.001) and mucosal thickness (P < 0.01) were significantly smaller in the TPN group than in the control group. The positively stained mucus area was significantly smaller in the TPN group than in the control group (P < 0.05 with PAS, P < 0.01 with FITC-UEA-I). Salmonella typhimurium invaded specifically through Peyer's patches. In all culture-negative samples, bacteria were trapped by the mucous layer, with a very small number attached to the epithelial surface. CONCLUSION: Significant villous atrophy and reduction of mucus play an important role in the rapid translocation of S. typhimurium through Peyer's patches in rats after 2 wk of TPN.

Animals↗
PubMed2004

Experimental studies to estimate the intestinal viability in a rat strangulated ileus model using a dielectric parameter.

This study aimed at establishment of adequate evaluation of intestinal viability before release of the strangulated intestine by measuring electrical properties. In rats a 20-cm segment of the distal ileum and mesentery was strangulated. The intestine was strangulated for 0, 2, 15, 45, 90, and 120 min. The conductance and capacitance obtained by impedance analyzer were used to calculate tan(delta)m in the strangulated intestine. ATP was measured as well. In another experiment, after various periods of strangulation, tan(delta)m was measured just before release of the strangulation. Rats were divided into Group A (survived for 7 days) and Group D (died within 7 days). There was a positive correlation between tan(delta)m and ATP levels (P < 0.01). And tan(delta)m was significantly greater in Group A than in Group D (P < 0.05). There were no deaths at a tan(delta)m value of 2.36 or more and no survivors at a tan(delta)m of less than 2.20 except for one rat. These results suggested that tan(delta)m may be a useful index of the viability of the strangulated intestine before reperfusion.

Adenosine Triphosphate↗
PubMed2004

Skeletal muscle targeting in vivo electroporation-mediated HGF gene therapy of bleomycin-induced pulmonary fibrosis in mice.

Lung fibrosis is a common feature of interstitial lung diseases, and apoptosis and fibrinogenesis play critical roles in its formation and progression. Hepatocyte growth factor (HGF) is one of the ideal therapeutic agents for prevention of lung fibrosis because of its antiapoptotic and fibrinolytic effects. The aim of this study is to establish nonviral HGF gene therapy of bleomycin-induced lung fibrosis avoiding the viral vector-related side effects. C57BL/6 mice were injected with 3.0 mg/kg body weight of bleomycin intratracheally. Following bleomycin injection, 50 microl of pUC-HGF (1 mg/ml) was injected into each of the quadriceps muscle. Immediately after plasmid injection, in vivo electroporation was performed with pulse generator. Skeletal muscle-targeting electroporation induced transgene expression on day 1 and persisted for 4 weeks, and human HGF was also detected in the lung. In mice transferred with HGF, pathological score (1.0+/-0.3 vs 3.2+/-0.6), TUNEL-positive cell index (4.5+/-1.1 vs 14.2+/-3.1), and hydroxyproline content (9.0+/-1.3 vs 14.4+/-5.1 micromol/g) were significantly reduced compared with the control. Furthermore, survival rate of HGF mice was significantly improved compared with the control. Our data indicate that HGF gene therapy with a single skeletal muscle-targeting electroporation has a therapeutic potential for bleomycin-induced lung fibrosis and this strategy can be applied as a practical gene therapy protocol for various organs.

Animals↗
PubMed2004

Immunogenicity of hylan g-f 20 in Guinea pigs and mice.

OBJECTIVE: To determine the product-specific immunogenicity of a chemically-modified sodium hyaluronate derivative, hylan G-F 20, that is used in the treatment of osteoarthritis of the knee. METHODS: Guinea pigs were subcutaneously immunized with hylan G-F 20 (Synvisc) once a week for 3 weeks. After resting, these animals received an intradermal challenge with hylan to elicit allergic skin reactions. Animal sera were tested for the presence of hylan-specific antibodies by homologous passive cutaneous anaphylaxis (PCA) assay and of anti-hylan IgG by ELISA. Further, mice were similarly immunized with hylan, and their sera were analyzed by heterologous PCA assay in rats and by ELISA for anti-hylan Ig(G+M) and anti-hylan IgE. RESULTS: In the guinea pig studies, acute and delayed erythematous skin reactions were elicited in immunized animals after the intradermal challenge with hylan. The sera of hylan-immunized guinea pigs showed positive reaction in the homologous PCA assay and significantly high amount of anti-hylan IgG, whereas the sera did not show any cross-reactivity against sodium hyaluronate. Hylan also exhibited immunogenicity in mice of 3 inbred strains, and C3H/HeN mice showed higher production of anti-hylan antibodies than Balb/c and C57BL/6 mice. CONCLUSION: Hylan G-F 20 exhibited immunogenicity in guinea pigs and mice. Recent reported severe acute inflammatory reactions in human patients after repeated intraarticular injections of hylan G-F 20 might involve product-specific, immune-mediated mechanisms.

Animals↗
PubMed2004

[Case report--total hip arthroplasty after femoral osteotomy].

Osteoarthritis that is the most common cartilage disease is difficult to treat conservatively. Usually it is treated by operative therapy. Osteotomy and arthroplasty are the popular operation. Osteotomy has a problem of unstable results. Some patients need arthroplasty after osteotomy, cause of getting worse of pain. It is difficult to operate arthroplasty for deformity of proximal femor after osteotomy. We report arthroplasty using ROBODOC is easy to operate cementless hip arthroplasty after osteotomy.

Arthroplasty, Replacement, Hip↗
PubMed2004

[Difficult cases of total knee arthroplasty].

We report two difficult cases in total knee arthroplasty (TKA). One is an arthritis mutilans knee with large tibial bone deficiency that required TKA using tibial metal wedge augmentation. Another is a post-traumatic OA knee with varus deformity and rotational malalignment that had TKA by the ROBODOC system.

Arthritis, Rheumatoid↗
PubMed2003

Distinctive expression patterns of heparan sulfate O-sulfotransferases and regional differences in heparan sulfate structure in chick limb buds.

The skeletal tissue development and patterning in chick limb buds are known to be under the spacio-temporal control of various heparin-binding cell growth factors such as fibroblast growth factors and bone morphogenetic proteins. Different structural regions on heparan sulfate (HS) chains of proteoglycans could be implicated in regional differences in the binding capacities of these cell growth factors, by which they could selectively interact with targeted cells and regulate their signaling in those processes. In this study we first demonstrated by cDNA cloning that one heparan sulfate 2-O-sulfotransferase (HS2ST) and two isoforms of heparan sulfate 6-O-sulfotransferase (HS6ST-1 and -2) occurred in chick embryos and had different substrate specificities each other. We next showed by whole mount in situ hybridization that the HS6ST-1 and HS6ST-2 transcripts were preferentially localized to the anterior proximal region and at the posterior proximal region of the limb bud, respectively, whereas the HS2ST transcript was distributed rather uniformly throughout the bud. Analyses of the structures of HS from different regions of the wing buds have shown variation in that 6-O-sulfated residues are more abundant in the proximal than distal region, whereas iduronosyl 6-O-sulfated residues are abundant in the anterior proximal region and glucuronosyl 6-O-sulfated residues in the posterior proximal region. These results suggest that HS with different sulfation patterns created with multiple sulfotransferase activities provides an appropriate extracellular environment for morphogenetic signal transduction.

Amino Acid Sequence↗
PubMed2003

Molecular heterogeneity of the SHAP-hyaluronan complex. Isolation and characterization of the complex in synovial fluid from patients with rheumatoid arthritis.

We previously found that a covalent complex of SHAPs (serum-derived hyaluronan-associated proteins), the heavy chains of inter-alpha-trypsin inhibitor family molecules, with hyaluronan (HA) is accumulated in synovial fluid of patients with rheumatoid arthritis, and the complex is circulated in patient plasma at high concentrations. How the SHAP-HA complex participates in this disease is unknown. To address this question, it is essential to clarify the structural features of this macromolecule. The SHAP-HA complex purified from synovial fluid of the patients by three sequential CsCl isopycnic centrifugations was heterogeneous in density, and the fractions with different densities had distinct SHAP-to-HA ratios. Agarose gel electrophoresis and column chromatography revealed that there was no apparent difference in the size distribution of HA to which SHAPs were bound between the fractions with different densities. The SHAP-HA complex in the higher density fraction had fewer SHAP molecules per HA chain. Therefore, the difference between the fractions with different densities was due to a heterogeneous population of the SHAP-HA complex, namely the different number of SHAP molecules bound to an HA chain. Based on the SHAP and HA contents of the purified preparations, we estimated that an HA chain with a molecular weight of 2 x 106 has as many as five covalently bound SHAPs, which could give a proteinaceous multivalency to HA. Furthermore, we also found that the SHAP-HA complex tends to form aggregates, judging from the migration and elution profiles in agarose gel electrophoresis and gel filtration, respectively. The multivalent feature of the SHAP-HA complex was also confirmed by the negative staining electron micrographic images of the purified fractions. Taken together, those structural characteristics may underlie the aggregate-forming and extracellular matrix-stabilizing ability of the SHAP-HA complex.

Alpha-Globulins↗