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Biomedical subjects

A Ishihara

Publications and source records attributed to A Ishihara.

At least 19 recordsLinked to original sources
PubMed2006

Head torsion technique for detailed observation of larynx and hypopharynx.

We introduce here an easy but effective method for detailed observation of the larynx and hypopharynx. During the endoscopic observation, the patient's head is turned to one side. Anatomical structures on the same side of the endolarynx, such as the laryngeal ventricle and inferior surface of the vocal fold, are easily observed. In addition, observation of the opposite side of the hypopharynx also becomes easier. Such head turning is also useful in patients with an oblique larynx, in whom the epiglottis obstructs insertion of the endoscope. This is a simple but very effective technique for laryngeal and hypopharyngeal observation.

Endoscopy↗
PubMed2006

Limits on the high-energy gamma and neutrino fluxes from the SGR 1806-20 giant flare of 27 December 2004 with the AMANDA-II detector.

On 27 December 2004, a giant gamma flare from the Soft Gamma-Ray Repeater 1806-20 saturated many satellite gamma-ray detectors, being the brightest transient event ever observed in the Galaxy. AMANDA-II was used to search for down-going muons indicative of high-energy gammas and/or neutrinos from this object. The data revealed no significant signal, so upper limits (at 90% C.L.) on the normalization constant were set: 0.05(0.5) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the gamma flux and 0.4(6.1) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the high-energy neutrino flux.

Journal Article↗
PubMed2006

Effects of hyperbaric exposure with high oxygen concentration on the physical activity of developing rats.

The effects of hyperbaric exposure with high oxygen concentration on the physical activity of developing male rats were investigated. Five-week-old male rats were exposed to an atmospheric pressure of 1.25 with an oxygen concentration of 36.0% for 12 h (7.00-19.00 h) and exercised voluntarily for 12 h (19.00-7.00 h) daily for 8 weeks. The voluntary running activities were compared with those in age-matched rats without hyperbaric exposure. In addition, the properties of the soleus and plantaris muscle fibers and their spinal motoneurons were examined. The voluntary running activities of rats with or without hyperbaric exposure increased during development. However, the mean voluntary running activities were higher in rats with hyperbaric exposure (7,104 m/day) than in those without hyperbaric exposure (4,932 m/day). The oxidative capacities of the soleus and plantaris muscle fibers and their spinal motoneurons increased following hyperbaric exposure. It is suggested that adaptations of neuromuscular units to hyperbaric exposure with high oxygen concentration enhance the metabolism, and thus, the function of neuromuscular units is promoted.

Animals↗
PubMed2006

Comparison of cell body size and oxidative enzyme activity in motoneurons between the cervical and lumbar segments in the rat spinal cord after spaceflight and recovery.

The cell body sizes and succinate dehydrogenase (SDH) activities of motoneurons in the dorsolateral region of the ventral horn at the cervical and lumbar segments in the rat spinal cord were determined following 9 days of spaceflight with or without 10 days of recovery on Earth. The motoneurons were divided into three types based on their cell body sizes; small-, medium-, and large-sized motoneurons. In control rats, there was no difference in the cell body size or SDH activity of small- and large-sized motoneurons between the cervical and lumbar segments. The SDH activity of medium-sized motoneurons in control rats was higher in the lumbar segment than in the cervical segment, while the cell body sizes of medium-sized motoneurons were identical. The SDH activity of medium-sized motoneurons in the lumbar segment decreased to a level similar to that in the cervical segment of control rats following spaceflight. In addition, the decreased SDH activity of medium-sized motoneurons persisted for at least 10 days of recovery on Earth. It is concluded that spaceflight selectively affects the SDH activity of medium-sized motoneurons in the lumbar segment of the spinal cord, which presumably innervate skeletal muscles having an antigravity function.

Animals↗
PubMed2006

Detection of COL1A1-PDGFB fusion transcripts and platelet-derived growth factor alpha and beta receptors in giant cell fibroblastoma of the postsacrococcygeal region.

We describe a 2-year-old girl with recurrent giant cell fibroblastoma (GCF) of the postsacrococcygeal region. Both the initial and recurrent tumours contained solid and angiectoid areas. The former was composed of loosely arranged wavy spindle cells and giant cells with a well-vascularized myxoid to collagenous stroma. The angiectoid spaces were often lined by multinucleated giant cells. Immunohistochemically, the tumour cells and small vessels in the tumour tissue were positive for platelet-derived growth factor (PDGF) alpha and beta receptors. Molecular analysis revealed fusion of collagen type Ialpha1 exon 26 with PDGF-B chain exon 2 that induced unscheduled production of PDGF-BB. These findings suggest that PDGF and its receptors significantly contribute to the development of GCF in both an autocrine and a paracrine manner.

Base Sequence↗
PubMed2006

Effects of running exercise on fibre-type distribution of soleus and plantaris muscles in diabetic Otsuka Long-Evans Tokushima fatty rats.

AIM: Effect of running exercise on fibre-type distributions of the slow soleus and fast plantaris muscles was investigated in male Otsuka Long-Evans Tokushima fatty rats (OLETF) as an animal model of spontaneous type 2 diabetes mellitus. METHODS: Five-week-old OLETF rats were allowed to exercise voluntarily in running wheels for 32 days and the data were compared with those of age-matched non-exercised OLETF and non-diabetic Long-Evans Tokushima Otsuka rats (LETO). RESULTS: In the soleus muscle, a higher percentage of type I fibres was observed in non-exercised OLETF rats compared with LETO rats, and there were no type IIA fibres in non-exercised OLETF rats. In the plantaris muscle, a higher percentage of type IIB fibres and a lower percentage of type I and type IIA fibres were observed in non-exercised OLETF rats compared with LETO rats. In contrast, there were no differences in the fibre-type distribution of soleus and plantaris muscles between exercised OLETF and LETO rats. The body weight and type I fibre percentage of the soleus muscle were related to the running distance in exercised OLETF rats. White adipose tissue weight, HbA(1c) and blood insulin and glucose concentrations were lower in exercised OLETF rats than in non-exercised OLETF rats, irrespective of the running distance. There was a difference in the gene-expression pattern of the soleus muscle among LETO rats, non-exercised OLETF and exercised OLETF rats. CONCLUSION: Running exercise can inhibit diabetes-associated type shifting of fibres, which is more apparent with postnatal growth, in skeletal muscles of diabetic OLETF rats, as a result of mRNA expression change in muscle.

Adipose Tissue↗
PubMed2005

Mechanical load-dependent regulation of satellite cell and fiber size in rat soleus muscle.

The effects of mechanical unloading and reloading on the properties of rat soleus muscle fibers were investigated in male Wistar Hannover rats. Satellite cells in the fibers of control rats were distributed evenly throughout the fiber length. After 16 days of hindlimb unloading, the number of satellite cells in the central, but not the proximal or distal, region of the fiber was decreased. The number of satellite cells in the central region gradually increased during the 16-day period of reloading. The mean sarcomere length in the central region of the fibers was passively shortened during unloading due to the plantarflexed position at the ankle joint: sarcomere length was maintained at <2.1 microm, which is a critical length for tension development. Myonuclear number and domain size, fiber cross-sectional area, and the total number of mitotically active and quiescent satellite cells of whole muscle fibers were lower than control fibers after 16 days of unloading. These values then returned to control values after 16 days of reloading. These results suggest that satellite cells play an important role in the regulation of muscle fiber properties. The data also indicate that the satellite cell-related regulation of muscle fiber properties is dependent on the level of mechanical loading, which, in turn, is influenced by the mean sarcomere length. However, it is still unclear why the region-specific responses, which were obvious in satellite cells, were not induced in myonuclear number and fiber cross-sectional area.

Animals↗
PubMed2005

Bile duct schwannoma developed in the remnant choledochal cyst-a case associated with total agenesis of the dorsal pancreas.

A 59-year-old Japanese woman was referred to our hospital due to upper abdominal pain. At the age of 44, she was diagnosed with a congenital choledochal cyst, Todani's type Ic. She then underwent bypass operation with end-to-side choledochojejunostomy with Roux-en-Y technique as well as cholecystectomy. Magnetic resonance cholangiopancreatography revealed an 'oval' shaped cystic lesion with a maximal diameter of 25 mm, which had been 'spindle' shaped with a maximal diameter of 18 mm, 15 years ago. It also showed an anomalous pancreaticobiliary ductal union. In addition, a complete absence of the dorsal primordia of pancreas was revealed by magnetic resonance image and computed tomography scan. The patient underwent the surgical exploration for the resection of the 'oval' shaped cystic lesion. Haematoxylin and eosin staining of the thin section of the resected cyst showed a compact spindle cell pattern which was compatible with schwannoma, Antoni type A, which was confirmed by immunocytochemical technique. We present a very interesting case showing choledochal cyst, anomalous pancreaticobiliary ductal union, total agenesis of the dorsal pancreas and late-development of bile duct schwannoma in the remnant choledochal cyst.

Abdominal Pain↗
PubMed2004

Tension- and afferent input-associated responses of neuromuscular system of rats to hindlimb unloading and/or tenotomy.

Responses of electromyogram (EMG) in soleus muscle and both afferent and efferent neurograms at the fifth lumbar (L(5)) segmental level of spinal cord were investigated during acute and chronic unloading induced by hindlimb suspension and/or tenotomy in adult rats. The soleus EMG and afferent neurogram decreased 88 and 37%, respectively, relative to those at quadrupedal posture on the floor after acute hindlimb suspension that causes passive shortening of soleus due to ankle plantarflexion. However, the afferent neurogram (P < 0.05) and soleus EMG (P > 0.05) recorded on the floor increased after tenotomy of synergists. Furthermore, the afferent input was inhibited when the soleus EMG disappeared after tenotomy of soleus. The afferent neurogram and EMG of the soleus showed correlated responses to a variety of treatments, suggesting that the afferent neurogram recorded at the L(5) segmental level reflects the neural input associated with the activity level of the soleus predominantly. The level of efferent neurogram decreased after acute hindlimb suspension but was not influenced significantly by tenotomy of synergists and/or soleus itself. The EMG and afferent neurograms remained low up to the 4th day but recovered to the preexperimental levels within 14 days, due to reorganization of sarcomere number and length, as well as the shortening of muscle fiber length and recovery of tension development. It is suggested that the levels of EMG and afferent neurogram associated with antigravity muscle are closely related to the tension development of the muscle.

Animals↗
PubMed2004

Hindlimb suspension inhibits air-righting due to altered recruitment of neck and back muscles in rats.

Effects of 9-week hindlimb suspension and 8-week recovery on air-righting reaction in response to drop from a supine position were studied in adult rats. The righting time in rats at the end of suspension (approximately 220 ms) was longer than the age-matched controls (approximately 120 ms, p <0.05). The unloading-related change in righting time was accompanied by lowered activities of electromyogram (EMG) and altered recruitment of both neck and back muscles at a specific stage of drop. After 8 weeks of reambulation, righting time recovered toward the control level (approximately 153 ms, p <0.05), but the EMG activity of back muscle was still less than controls. In contrast, the EMG of neck muscle during fall was even increased. The differences in the characteristics of the muscle fibers between two groups were minor. It is suggested that inhibition of recruitment, rather than the changes in the fiber characteristics, of neck and back muscles is one of the major causes of the slow air-righting.

Adaptation, Physiological↗
PubMed2003

Three-pion Hanbury Brown-Twiss correlations in relativistic heavy-ion collisions from the STAR experiment.

Data from the first physics run at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory, Au+Au collisions at sqrt[s(NN)]=130 GeV, have been analyzed by the STAR Collaboration using three-pion correlations with charged pions to study whether pions are emitted independently at freeze-out. We have made a high-statistics measurement of the three-pion correlation function and calculated the normalized three-particle correlator to obtain a quantitative measurement of the degree of chaoticity of the pion source. It is found that the degree of chaoticity seems to increase with increasing particle multiplicity.

Journal Article↗
PubMed2003

Screening of tetrachlorodibenzo- p-dioxin-degrading fungi capable of producing extracellular peroxidases under various conditions.

Forty-six pulp-bleaching fungi were screened for production of key enzymes for conversion of polychlorinated dibenzo-p-dioxins--lignin peroxidase (LiP), manganese peroxidase (MnP), and manganese-independent peroxidase (MiP)--under various conditions that would allow their utilization in the environment. Of 38 MnP-producing strains with MiP activity, 22 produced LiP. Three of the new isolates, Bjerkandera sp. strains MS191, MS325, and MS1167, were the best producers of the three different peroxidases, and had reasonable growth rates. The most promising Bjerkandera sp. strain, MS325, exhibited significant levels of LiP and MnP activities under various conditions, e.g., nutrient nitrogen-sufficient or -limited conditions, conditions with or without Mn(II), and changes in temperature (15-37 degrees C). Furthermore, the ability of this strain to degrade 1,3,6,8-tetrachlorodibenzo- p-dioxin was confirmed. The results presented here indicate that utilization of Bjerkandera sp. strain MS325 on a practical scale in the environment has several advantages over many white rot fungi, which produce extracellular peroxidases only under specific conditions such as nutrient limitation.

Azure Stains↗
PubMed2003

Narrowing of the balance function with centrality in Au+Au collisions at the square root of SNN = 130 GeV.

The balance function is a new observable based on the principle that charge is locally conserved when particles are pair produced. Balance functions have been measured for charged particle pairs and identified charged pion pairs in Au+Au collisions at the square root of SNN = 130 GeV at the Relativistic Heavy Ion Collider using STAR. Balance functions for peripheral collisions have widths consistent with model predictions based on a superposition of nucleon-nucleon scattering. Widths in central collisions are smaller, consistent with trends predicted by models incorporating late hadronization.

Journal Article↗
PubMed2003

Disappearance of back-to-back high-pT hadron correlations in central Au+Au collisions at sqrt[s NN ] =200 GeV.

Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudorapidity range and full azimuth in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. The small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes previously observed in high-energy collisions. A strong back-to-back correlation exists for p+p and peripheral Au+Au. In contrast, the back-to-back correlations are reduced considerably in the most central Au+Au collisions, indicating substantial interaction as the hard-scattered partons or their fragmentation products traverse the medium.

Journal Article↗
PubMed2003

Azimuthal anisotropy and correlations in the hard scattering regime at RHIC.

Azimuthal anisotropy (v(2)) and two-particle angular correlations of high p(T) charged hadrons have been measured in Au+Au collisions at sqrt[s(NN)]=130 GeV for transverse momenta up to 6 GeV/c, where hard processes are expected to contribute significantly. The two-particle angular correlations exhibit elliptic flow and a structure suggestive of fragmentation of high p(T) partons. The monotonic rise of v(2)(p(T)) for p(T)<2 GeV/c is consistent with collective hydrodynamical flow calculations. At p(T)>3 GeV/c, a saturation of v(2) is observed which persists up to p(T)=6 GeV/c.

Journal Article↗
PubMed2003

Salvage chemotherapy with a combination of irinotecan hydrochloride and mitomycin C in platinum- and paclitaxel-resistant epithelial ovarian cancer: case reports.

INTRODUCTION: The efficacy and toxicity of salvage chemotherapy with a combination of irinotecan hydrochloride (CPT-11) and mitomycin C (MMC) for platinum-and paclitaxel-resistant epithelial ovarian cancer are reported. CASE REPORT: Three consecutive patients with platinum- and paclitaxel- resistant epithelial ovarian cancer were treated with 120 mg/m2 of CPT-11 (days 1 and 15) and 7 mg/m2 of MMC (days 1 and 15) every four weeks. In all three cases partial responses were achieved and overall survivals were 17 months or longer. Most of the adverse side-effects were manageable. CONCLUSIONS: This regimen could be administered even in heavily pretreated patients with platinum- and paclitaxel- resistance. Phase I and II studies are needed to confirm the feasibility of this treatment. The efficacy of most salvage treatments for platinum- and paclitaxel-resistant epithelial ovarian cancer is disappointing, and our cases might be of interest from the perspective of treating platinum- and paclitaxel-resistant ovarian cancer.

Aged↗
PubMed2003

Effects of aging and exercise on density and cross-sectional area of femur in senescence-accelerated mouse prone 6.

The densities and cross-sectional areas (CSAs) of the femur in 40- and 60-week-old senescence-accelerated mice prone 6 (SAMP6) were determined using peripheral quantitative computed tomography (pQCT) and compared with those in age-matched control mice (ICR). In addition, the effects of 20 weeks of voluntary running exercise with increasing loads on femur density and CSA were examined in SAMP6. There were no differences in the cortical and trabecular densities or CSAs between the 40- and 60-week-old ICR. The cortical and trabecular densities of the 60-week-old control SAMP6 were lower than those of the 40-week-old control SAMP6. There was no difference in the cortical CSA between the 40- and 60-week-old control SAMP6, while the trabecular CSA of the 60-week-old control SAMP6 was higher than that of the 40-week-old control SAMP6. It was concluded that an age-related decline in femur cortical and trabecular densities occurs at an earlier age in control SAMP6, indicating that SAMP6 show accelerated progression of age-associated osteoporosis. There were no differences in the cortical density between the 40-week-old control and 60-week-old exercised SAMP6. These data indicate that running exercise with increasing loads prevents age-associated osteoporosis in this senescence-accelerated mouse strain.

Journal Article↗