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T Shibata

Publications and source records attributed to T Shibata.

At least 19 recordsLinked to original sources
PubMed2006

Portal blood flow regulates volume recovery of the rat liver after partial hepatectomy: molecular evaluation.

BACKGROUND/AIM: Liver regeneration is a finely tuned process that is closely regulated by multiple cell cycle steps. Although the portal blood flow affects liver regeneration, the molecular mechanism by which the blood flow regulates gene expression and liver function is largely unknown. The aim of this study was to investigate the molecular effect of portal blood flow on hepatocyte proliferation and gene regulation during liver regeneration. MATERIALS AND METHODS: We developed a simple surgical rat model to investigate the relation between portal blood flow and liver regeneration by partially ligating the portal trunk with 8-0 Proline sutures under microscopy to reduce the blood flow by 40%. We investigated recovery of liver volume, DNA synthesis, and gene expression associated with cell cycle regulators, comparing partially hepatectomized (PH) rats without (PH group; n = 30) and with partial portal ligation (PHPL group; n = 30) for 7 days after the operation. RESULTS: The hepatic tissue blood flow and the recovery ratio between liver weight and body weight in the PHPL group were significantly lower than in the PH group after hepatectomy. The peak 5-bromo-2'-deoxyuridine labeling index in the PHPL group was delayed and weak compared with the PH group. The expression of CT-1 and cyclin D, E, and B mRNAs indicated that the liver regeneration in the PHPL group was delayed and weak. In addition, there was reciprocal expression of C/EBPalpha and C/EBPbeta mRNAs, an observation supported by their nuclear protein levels. Furthermore, the cytochrome P-450 protein level in the PHPL group was higher than that in the PH group 1 day after hepatectomy. CONCLUSION: The portal blood flow regulates the activity of liver regeneration and the gene expression associated with cell cycle regulators, while the functions are maintained.

Animals↗
PubMed2006

Stress-relaxation and microscopic dynamics of rabbit periodontal ligament.

The aim of the present study was to examine the structural basis for the stress-relaxation behaviour of the periodontal ligament (PDL). Seventeen 4-month-old rabbits were used. A tooth-PDL-bone segment was cut in a rectangular prism from the incisor of a dissected mandible. The specimen was mounted in a testing machine built on a video stereomicroscope. Following preconditioning, each specimen was stretched to a deformation of 35 microm and then the deformation was kept constant for 300 s to obtain a stress-relaxation curve. Thereafter, stress-relaxation tests were repeated sequentially at deformations of 55, 75, and 95 microm. Polarised-light video-stereomicroscopic images of the specimens were simultaneously recorded and analysed with the stress-relaxation curves. The image analysis revealed that during stress-relaxation, the brightness of the birefringent fibres tended to initially increase rapidly and then do so gradually. There were negative correlations between the brightness and relaxation modulus at the four deformations. The decreases of normalised relaxation modulus for 300 s were less at greater deformation levels. The stress-relaxation process was well described by a function with three exponential decay terms and a constant. These findings suggest that during stress-relaxation of the PDL, the alignment of the collagen molecules and fibrils within the stretched fibres may occur, which could be driven by the strain energy imparted to the specimen on initial stretching.

Animals↗
PubMed2006

A pilot study of children's exposure to CCA-treated wood from playground equipment.

Arsenic from chromated copper arsenate (CCA)-treated wood, widely used in playgrounds and other outdoor equipment, can persist as surface residues on wood. This raises concerns about possible health risks associated with children playing on CCA-treated playgrounds. In a Pilot Study, 11 children (13-71 months) in homes with and without CCA-treated playgrounds were evaluated with post-exposure hand rinses and urine for total arsenic. Samples of wood, soil, and mulch, as well as synthetic wipes, were sampled for total arsenic. In non-CCA-treated playgrounds vs. CCA-treated playgrounds, respectively, wood arsenic was <2.0 mg/kg vs. mean arsenic 2370 mg/kg (range 1440-3270 mg/kg); soil arsenic was <3.0 mg/kg vs. mean arsenic of 19 mg/kg (range 4.0-42 mg/kg); mulch arsenic at one non-CCA-treated playground was 0.4 mg/kg vs. two CCA-treated playgrounds of 0.6 and 69 mg/kg. The arsenic removed using a synthetic wipe at non-CCA-treated playgrounds was <0.5 microg, while mean arsenic from CCA-treated wood was 117 microg (range 1.0-313). The arsenic mass from hand rinses for children who played at non-CCA-treated playgrounds was <0.2 microg, while mean arsenic mass was 0.6 microg (range <0.2-1.9) at CCA-treated playgrounds. Mean urinary total arsenic levels were 13.6 pg/ml (range 7.2-23.1 pg/ml) for all children evaluated, but there was no association between access to CCA-playgrounds and urinary arsenic levels. Arsenic speciation was not performed. This preliminary Pilot Study of CCA-treated wood playgrounds observed dislodgeable arsenic on 11 children's hands after brief periods of play exposure. Future efforts should increase the number of children and the play exposure periods, and incorporate speciation in order to discriminate between various sources of arsenic.

Arsenates↗
PubMed2006

Prednisolone inhibits hyperosmolarity-induced expression of MCP-1 via NF-kappaB in peritoneal mesothelial cells.

The mechanism of peritoneal fibrosis in patients on continuous ambulatory peritoneal dialysis (CAPD) is poorly elucidated. We investigated the cellular mechanism of high-glucose-induced expression of monocyte chemoattractant protein-1 (MCP-1), which is important in recruiting monocytes into the peritoneum and progression of peritoneal fibrosis, and examined the inhibitory mechanism of glucocorticoids. Rat peritoneal mesothelial cells were cultured in high-glucose-containing medium and then analyzed for phosphorylation levels of p42/44 and p38 mitogen-activated protein (MAP) kinases (MAPK), MAPK or extracellular signal-regulated kinase kinase (MEK)1/2, c-Jun N-terminal kinase (JNK)1/2, and protein kinase C (PKC) by Western blotting. Expression of MCP-1 was examined by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. DNA-binding activity of nuclear factor (NF)-kappaB was measured by electrophoretic mobility shift assay. High glucose increased MCP-1 mRNA and MCP-1 protein expression. Although glucose increased phosphorylation of MEK1/2, p42/44 MAPK, p38 MAPK, JNK1/2, and PKC, and DNA-binding activity of NF-kappaB, its effect on MCP-1 expression was suppressed only by PKC and NF-kappaB inhibitors. Mannitol caused a similar increase in PKC and NF-kappaB activation and MCP-1 synthesis. Prednisolone increased I-kappaB-alpha expression and inhibited glucose/mannitol-induced NF-kappaB DNA binding and MCP-1 expression without affecting PKC phosphorylation. The inhibitory effects of prednisolone on MCP-1 expression were reversed by mifepristone, a glucocorticoid receptor antagonist. Our results indicate that glucose induces MCP-1 mainly through hyperosmolarity by activating PKC and its downstream NF-kappaB, and that such effect was inhibited by prednisolone, suggesting the efficacy of prednisolone in preventing peritoneal fibrosis in patients on CAPD.

Animals↗
PubMed2006

JTP-426467 acts as a selective antagonist for peroxisome proliferator-activated receptor gamma in vitro and in vivo.

AIM: JTP-426467 was identified as a result of screening in search of selective antagonist for peroxisome proliferator-activated receptor gamma (PPARgamma). We examined whether JTP-426467 functioned as a PPARgamma antagonist in vitro and in vivo and investigated physiological effects of JTP-426467. METHODS: The effect of JTP-426467 as a PPARgamma antagonist was studied in a cell-based reporter assay and an adipocyte differentiation assay. Target mRNA expression levels were determined by branched DNA (bDNA) assay. To examine the effects as a PPARgamma antagonist in vivo, a competitive study between JTP-426467 and BRL49653 (rosiglitazone), a PPARgamma agonist, was performed using KK-Ay mice. The effects of JTP-426467 alone after administration to KK-Ay mice were also explored. JTP-426467 antagonized PPARgamma activity in a reporter assay system, but not PPARalpha. RESULTS: JTP-426467 inhibited the expression of hormone-sensitive lipase (HSL) mRNA, an adipocyte-abundant gene, but not PPARgamma itself or cyclophilin mRNA (as constitutive mRNA), and also suppressed triglyceride accumulation in differentiated stromal vascular fraction cells (SVFs). JTP-426467 antagonized PPARgamma agonistic action by BRL49653 in KK-Ay mice on high-fat diet, in terms of plasma glucose, body weight gain and interscapular brown adipose tissue (IBAT) weight. JTP-426467 alone inhibited body weight gain and decreased plasma leptin level in KK-Ay mice. CONCLUSIONS: JTP-426467 acted as a pure and potent PPARgamma antagonist in vitro. Interestingly, JTP-426467 completely antagonized the effects of PPARgamma agonist BRL49653 in an obese diabetic model. JTP-426467 may be a useful tool for the study of PPARgamma in biological and physiological function.

Adipocytes↗
PubMed2006

Minor gene effect of leptin receptor variant on the body weight in KK/Ta mice.

OBJECTIVE: Leptin is an adipocyte-derived hormone involved in body weight regulation that acts through the leptin receptor. Previous studies exploring potential association between the leptin receptor (Lepr) variant and obesity have reported conflicting results. The objectives of the present study are to evaluate (1) whether the Lepr variant contributes to type 2 diabetes and its related disorders such as obesity and (2) whether the gene interaction between Lepr and Zn-alpha(2) glycoprotein1 (Azgp1) genes is recognized using genetically homogeneous type 2 diabetic KK/Ta mice. METHODS: The levels of leptin (Lep) and Lepr mRNA in adipose tissues and brain were measured by relative quantitative RT-PCR. The levels of leptin protein in sera were measured by enzyme-linked immunosorbent assay. Genotyping of backcross mice was performed using a mismatch primer. RESULTS: Leptin protein and its mRNA levels were increased in KK/Ta mice. Lepr mRNA levels of KK/Ta mice did not differ from those of BALB/c mice. Sequence analysis revealed that the coding region of Lep in KK/Ta mice was identical to that in BALB/c mice. Six nucleotide polymorphisms were observed in the coding region of Lepr. In KK/Ta x (BALB/c x KK/Ta) F1 backcross mice, the Lepr variant of KK/Ta mice failed to alter any of the variables of obesity except for body weight at 20 weeks of age. However, it enhanced the effect of Azgp1 on body weight. CONCLUSION: It is concluded that the Lepr variant contributes to obesity to some degree in KK/Ta mice.

Adipose Tissue↗
PubMed2006

Genetic correlations among fatty acid compositions in different sites of fat tissues, meat production, and meat quality traits in Duroc pigs.

This study estimated genetic parameters for fatty acids of different sites of fat tissue, meat production, and meat quality traits of Duroc pigs selected during 7 generations for ADG, LM area, backfat thickness (BF), and intramuscular fat (IMF). For this study, 394 barrows and 153 gilts were slaughtered at 105 kg of BW. High heritabilities for C18:0 of outer and inner subcutaneous fat tissue were estimated, respectively, as 0.54 and 0.51; those of intermuscular and intramuscular fat were 0.40 and 0.51, respectively. Genetic and phenotypic correlations of ADG and BF with saturated fatty acids of outer and inner subcutaneous fat were positive, but those with C16:1 and C18:2 were negative, and those with C18:1 were nearly zero. Genetic and phenotypic correlations between LM area and respective fatty acids showed opposite results. Respective genetic and phenotypic correlations of melting points with C18:0 and C18:1 were positive and high, and negative and high, respectively. Genetic correlations between cooking loss and SFA (C14:0, C16:0, and C18:0) of IMF were positive and moderate: 0.56, 0.47, and 0.47, respectively. On the other hand, monosaturated fatty acid of C18:1 was highly and negatively correlated with cooking loss (-0.61). Moreover, high genetic correlation between meat color (pork color standard and lightness) and fatty acid compositions of IMF suggest that the SFA (C14:0, C16:0, and C18:0) were correlated genetically with meat lightness and that unsaturated fatty acid compositions (C18:1 and C18:2) were correlated with meat darkness. Results of this study suggest that the fatty acid composition of adipose tissue is correlated genetically with meat production and meat quality traits.

Adipose Tissue↗
PubMed2006

Rapidly progressive glomerulonephritis in a patient with Chlamydia pneumoniae infection: a possibility of superantigenic mechanism of its pathogenesis.

Herein we describe a case of a patient with rapidly progressive glomerulonephritis after Chlamydia pneumoniae infection. An 88-year-old woman who had had C. pneumoniae infection two months previously was admitted to our hospital with complaints of dyspnea and generalized edema. Laboratory tests revealed acute renal failure, polyclonal hypergammaglobulinemia, highly increased level of C-reactive protein, and hematoproteinuria. A renal biopsy revealed mesangial and endocapillary proliferative glomerulonephritis with crescents. She responded to high-dose steroids, cyclophosphamide, minocycline, and plasma exchange treatment with the remission of oliguric renal failure. The percentage of the subset of CD3+ TCR+ Vbeta11+ cells markedly increased to 9.6% (normal range: < 1.04%) at the onset of the disease and decreased to 0.1% after the treatment. These clinicopathological features were similar to those of superantigen-associated glomerulonephritis after methicillin-resistant Staphylococcus aureus infection. We suggest that the superantigenic mechanism is one of the possible pathomechanisms of this glomerulonephritis.

Aged↗
PubMed2006

A case of refractory uremic pleuropericarditis--successful corticosteroid treatment.

We report the case of a patient with uremic pleuropericarditis who showed a marked improvement following corticosteroid therapy. A 66-year-old man who had been on hemodialysis therapy for 13 years was admitted to our hospital presenting with increases in bilateral pleural effusions and pericardial effusion. Repeated thoracentesis showed hemorrhagic and exudative findings. Pleural and pericardial fluid cytologic examination, bacterial culture and acid-fast staining showed negative findings. Despite the administration of antibiotics and antituberculosis drugs, low-grade fever continued and C-reactive protein level remained high. A pleural biopsy revealed fibrinous pleuritis without infectious disease or malignancy. He was diagnosed as having uremic pleuropericarditis on the basis of the clinicopathological features, but had been unresponsive to conventional treatments including repeated thoracentesis and the continuance of hemodiafiltration using nafamostat mesylate. Ultimately, both pleural and pericardial effusions were controlled after the treatment with prednisolone at an initial dose of 50 mg per day. In conclusion, corticosteroid therapy seems to be useful for treating patients with conventional therapy-resistant uremic pleuropericarditis.

Aged↗
PubMed2006

[Successful off-pump coronary artery bypass for a patient with aplastic anemia].

We report a 61-year-old man with aplastic anemia who underwent successful off-pump coronary artery bypass (OPCAB) after being admitted for angina pectoris. Coronary angiography showed severe stenosis of the left main coronary artery. Preoperative WBC was 2,200/microl, neutrophil 704/microl, Hb 8.1g/dl, and PLT 16,000/microl. We conducted OPCAB on double vessels using left internal thoracic and radial artery grafts. Thirty units of platelets were transfused intraoperatively with little perioperaive hemorrhage. Because of high grade fever, we injected 150 microg granulocyte colony-stimulating factor (G-CSF) every 3 days postoperatively to prevent major infection. The combination of appropriate perioperative management and OPCAB yielded an effective result for a patient with severe hematological disorders causing pancytopenia.

Anemia, Aplastic↗
PubMed2006

[Aortic root replacement in Marfan syndrome with hemophilia A].

A 34-year-old man with Marfan syndrome was admitted to our hospital for surgical treatment of aortic regurgitation due to annuloaortic ectasia. He had no history of bleeding complications. Preoperative investigation revealed a slight prolongation of an activated partial thromboplastin time, which went unnoticed. He underwent aortic root replacement with a composite valve graft. During the operation, he had excessive bleeding due to coagulopathy after the termination of cardiopulmonary bypass, and needed a large amount of blood transfusion to obtain hemostasis. Before his discharge from our hospital, he was diagnosed as mild hemophilia A because of the decline in his factor VII level. To our knowledge, there has been no published case of cardiac operations in Marfan syndrome with hemophilia A.

Adult↗
PubMed2006

[New proximal anastomotic system in coronary artery bypass grafting].

The Heartstring proximal anastomotic system is a device designed to facilitate the creation of a clampless hand-sewn proximal anastomosis. Thirty-four patients who underwent coronary artery revascularization had 40 proximal anastomoses using the Heartstring device. There were 26 men and 8 women, with the mean age of 70 +/- 8.9 years. Thirty-one patients underwent coronary artery bypass grafting through off-pump procedures and 3 patients on-pump beating procedures. In all patients, saphenous vein grafts were anastomosed to the aorta using the Heartstring device, the median number of distal anastomoses being 2.4 +/- 0.7. Either emergent or urgent surgery was required in 14 patients (41%). Diseased aorta was found in 11 patients (32%). One patient (2.9%) died postoperatively due to ischemic necrosis of the small intestine and the colon. There was no occurrence of postoperative stroke. Of 40 saphenous vein grafts anastomosed with the Heartstring system, 39 (97.5%) were patent. The occluded saphenous vein was not considered to be device related. Our clinical experience demonstrated that the Heartstring system allow us to create clampless and reproductive hand-sewn proximal anastomosis and to decrease the incidence of neurological complication.

Aged↗
PubMed2005

Optical circuit design based on a wavefront-matching method.

We propose an optical circuit design method for coherent waves as a boundary value problem. The method produces a very compact circuit in which the refractive index pattern is automatically synthesized for given input and output fields with a numerical calculation. We employ the method to design a 1.3/1.55 microm wavelength demultiplexer and also describe the features of a circuit generated by use of the method.

Journal Article↗
PubMed2005

Relationship between the pharyngeal airway space and craniofacial morphology, taking into account head posture.

This study assessed the relationship between craniofacial characteristics and the size of the pharyngeal airway space (PAS), taking into account head posture. Sixty dental students 25-30 years of age (30 men and 30 women) were examined by lateral cephalometry. The data were corrected with the use of appropriate regression equations for the PAS. The PAS significantly correlated with hyoid position, maxillary and mandibular size, maxillary and mandibular prognathism, and mandibular inclination. A large, anteriorly positioned mandible was associated with a large PAS-TP (the most proximal distance between the posterior pharyngeal wall and the tongue base). Uvula length and PNS-Ba (the distance between the most posterior point of the hard palate and the most inferior point of the anterior foramen magnum) correlated with PAS-UP (the most proximal distance between the posterior pharyngeal wall and uvula). Our results suggest that the anteroposterior dimension of the PAS is substantially affected by the size of the enclosure surrounding the PAS, including the maxilla, mandible and soft palate.

Adult↗
PubMed2005

Intraoral minor salivary gland tumors: a clinicopathological study of 82 cases.

We present a retrospective study of 82 patients with intraoral minor salivary gland tumors which were diagnosed from 1979 to 2003 in Gifu University Hospital. The histological diagnoses were reevaluated according to the 1991 WHO classification. A total of 82 tumors, consisting of 55 benign and 27 malignant tumors, were found in 28 male and 54 female Japanese patients; the male-to-female ratio was 1:1.9. The mean age of the patients was 51.4+/-18.1 years. The tumors affected the palate (n = 64), the buccal region (n = 10), the upper lip (n = 6), the floor of the mouth (n = 1), and the retromolar region (n = 1). Histologically, the tumors were classified as pleomorphic adenoma (n = 54), papillary cystadenoma (n = 1), adenoid cystic carcinoma (n = 10), mucoepidermoid carcinoma (n = 8), acinic cell carcinoma (n = 3), adenocarcinoma (n = 2), basal cell adenocarcinoma (n = 1), papillary cystadenocarcinoma (n = 1), and carcinoma in pleomorphic adenoma (n = 2). From the results of the present study and review of the literature, it is suggested that the minor salivary gland tumors in Japan may be characterized by a higher incidence of benign tumors, especially of pleomorphic adenoma; a more marked tendency for female predominance; a higher incidence of palatal involvement; and a rarer occurrence of polymorphous low grade adenocarcinoma, in comparison with those reported in the literature from outside of Japan.

Adenocarcinoma↗
PubMed2005

Pharyngeal narrowing as a common feature in pycnodysostosis--a cephalometric study.

We report on pycnodysostosis presenting as severe snoring caused by pharyngeal narrowing in two siblings. Cephalograms showed pharyngeal narrowing at the level of the soft palate and the base of the tongue caused by the long soft palate and mandibular hypoplasia. From the literature review and our results, we suggest that respiratory insufficiency such as snoring or obstructed sleep apnea are common and under-appreciated symptoms of pycnodysostosis.

Aged↗