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T Sugawara

Publications and source records attributed to T Sugawara.

At least 55 records · Page 3Linked to original sources
PubMed2001

Early decrease in dna repair proteins, Ku70 and Ku86, and subsequent DNA fragmentation after transient focal cerebral ischemia in mice.

BACKGROUND AND PURPOSE: Ku70 and Ku86, multifunctional DNA repair proteins, bind to broken DNA ends, including double-strand breaks, and trigger a DNA repair pathway. To investigate the involvement of these proteins in DNA fragmentation after ischemia/reperfusion, Ku protein expression was examined before and after transient focal cerebral ischemia (FCI) in mice. METHODS: Adult male CD-1 mice were subjected to 60 minutes of FCI by intraluminal suture blockade of the middle cerebral artery. Ku protein expression was studied by immunohistochemistry and Western blot analysis. DNA fragmentation was evaluated by gel electrophoresis and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL). The spatial relationship between Ku expression and DNA fragmentation was examined by double labeling with Ku and TUNEL after reperfusion. RESULTS: Immunohistochemistry showed constitutive expression of Ku proteins in control brains. The number of Ku-expressing cells was decreased in the entire middle cerebral artery territory as early as 4 hours after reperfusion and remained reduced until 24 hours. Western blot analyses confirmed the significant reduction of these proteins (59.4% and 57.7% reduction in optical density at 4 hours of reperfusion from the normal level of Ku70 and Ku86 bands, respectively; P<0.001). DNA gel electrophoresis demonstrated DNA laddering 24 hours after reperfusion, but not at 4 hours. Double staining with Ku and TUNEL showed a concomitant loss of Ku immunoreactivity and TUNEL-positive staining. CONCLUSIONS: These results suggest that the early reduction of Ku proteins and the loss of defense against DNA damage may underlie the mechanism of DNA fragmentation after FCI.

Animals↗
PubMed2001

Neuronal expression of the DNA repair protein Ku 70 after ischemic preconditioning corresponds to tolerance to global cerebral ischemia.

BACKGROUND AND PURPOSE: Oxidative stress after ischemia/reperfusion has been shown to induce DNA damage and subsequent DNA repair activity. Ku 70/86, multifunctional DNA repair proteins, bind to broken DNA ends and trigger a DNA repair pathway. We investigated the involvement of these proteins in the development of neuronal tolerance to global cerebral ischemia after ischemic preconditioning. METHODS: Adult male Sprague-Dawley rats were subjected to either 5 minutes of lethal global ischemia with or without 3 minutes of sublethal ischemic preconditioning or 3 minutes of ischemia only. Neuronal injury was histologically assessed, and DNA damage was visualized by in situ labeling of DNA fragmentation and DNA gel electrophoresis. Ku expression was also examined by immunohistochemistry and Western blot analysis. RESULTS: Hippocampal CA1 neurons underwent DNA-fragmented cell death 3 days after 5 minutes of ischemia. However, these neurons showed a strong tolerance to 5 minutes of ischemia 1 to 3 days after ischemic preconditioning. Immunohistochemistry showed virtually no constitutive expression of Ku proteins in CA1 neurons; however, ischemic preconditioning induced neuronal Ku 70 expression 1 to 3 days later. Western blot confirmed an increase in Ku 70 in this region at the same time. CONCLUSIONS: The temporal and spatial expression of Ku 70 corresponded to tolerance of the hippocampal CA1 neurons to subsequent ischemia, suggesting the involvement of Ku proteins in the development of neuronal tolerance after ischemic preconditioning.

Animals↗
PubMed2001

RIP 140 modulates transcription of the steroidogenic acute regulatory protein gene through interactions with both SF-1 and DAX-1.

Coregulators have been suggested to act as a bridging apparatus between nuclear receptors and the transcriptional machinery. The orphan receptor SF-1 plays a role in controlling the basal and cAMP-stimulated expression of the human steroidogenic acute regulatory protein gene. DAX-1 is the gene responsible for X-linked adrenal hypoplasia congenita and blocks steroid biosynthesis by impairing the expression of steroidogenic acute regulatory protein. In the present study we examined the role of coregulators in the actions of SF-1 and DAX-1 on the human steroidogenic acute regulatory protein promoter. We found that the coregulator RIP 140 interacts with SF-1 in the yeast two-hybrid system. Glutathione-S-transferase pull-down assays and coimmunoprecipitations confirmed the interaction between RIP 140 and SF-1. RIP 140 was also shown to interact with DAX-1. When an RIP 140 expression vector was introduced into Y-1 cells, basal and cAMP-stimulated human steroidogenic acute regulatory protein promoter activities decreased. The inhibitory effect of RIP 140 on human steroidogenic acute regulatory protein promoter activity was dependent upon the presence of SF-1. The cAMP response of an SF-1 response element was inhibited by both RIP 140 and DAX-1 expression vectors at low concentrations of plasmids. We conclude that RIP 140 binds to the orphan nuclear receptor SF-1 and DAX-1 and modulates their actions on the human steroidogenic acute regulatory protein promoter.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Solution-phase automated synthesis of tripeptide derivatives.

An improved general method for automated synthesis of tripeptides was developed, in which methanesulfonic acid (MSA) was used in place of trifluoroacetic acid (TFA), thus making it possible to avoid, 1) corrosion of the apparatus by strong acid vapor, 2) formation of emulsions, and 3) use of the restricted solvent, dichloromethane. As an application of the automated synthesis apparatus, 216 fragment tripeptide derivatives were synthesized systematically using the MSA method, in excellent yield and with increased efficiency.

Automation↗
PubMed2001

Application of an automated synthesis suite to parallel solution-phase peptide synthesis.

An in-house developed automated synthesis suite was used to prepare a library of 72 tetrapeptide derivatives, the starting materials for pharmaceutically attractive pentapeptides, employing a convergent strategy. An initial set of 18 dipeptides were synthesized on a large-scale (100-1000 g) using automated synthesis workstations, and then 72 tetrapeptides were synthesized on a medium scale (5-10 g) using an automated system. Each di- or tetrapeptide was prepared in a single operating cycle using a modified methanesulfonic acid method, then a sub-library of 56 pentapeptides were synthesized in parallel, on a small-scale (100 mg-1 g) using a robotic workstation.

Carboxylic Acids↗
PubMed2001

Coronary capillary remodeling in non-insulin-dependent diabetic rats: amelioration by inhibition of angiotensin converting enzyme and its potential clinical implications.

Using Otsuka Long Evans Tokushima Fatty (OLETF) rats, a model of human non-insulin-dependent diabetes mellitus (NIDDM) that exhibits hypertension, obesity, hyperglycemia and hyperlipidemia, the role of local angiotensin II in cardiovascular complications at early stages of NIDDM was characterized. OLETF rats were given an angiotensin converting enzyme (ACE) inhibitor, cilazapril (10 mg/kg/day) or vehicle from the age of 5 weeks to 20 weeks. Arteriolar, intermediate and venular capillary proportions were determined by the double-staining method and levels of collagen and non-collagenous proteins were determined by the selective dye-binding method in heart tissues. In OLETF rats at 20 weeks of age, capillary network remodeling (i.e., an increase in arteriolar portions and a decrease in venular portions) and an increase in collagen content were detected. Cilazapril not only exerted favorable effects on markers of diabetes, but also prevented capillary network remodeling and ameliorated the increase in collagen content. These results suggest that 1) capillary network remodeling and increase in extracellular matrix protein levels precede the onset of overt NIDDM in OLETF rats, and 2) angiotensin II may be involved in the pathogenesis of cardiac complications in the early stages of NIDDM.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2001

A case of influenza subtype A virus-induced fulminant myocarditis: an experience of percutaneous cardio-pulmonary support (PCPS) treatment and immunohistochemical analysis.

A 64-year-old man was admitted to the emergency center of Furukawa City Hospital because of common cold-like symptoms and hypotension. He was diagnosed as fulminant myocarditis with cardiogenic shock and arrhythmia elicited by influenza virus subtype A. Cardiac angiography, echocardiography and biopsy also showed myocarditis, and serum antibody titer to influenza virus subtype A was increased to 4-fold in paired serums. Treatments of both percutaneous cardio-pulmonary support (PCPS) and intra-aortic balloon pumping (IABP) were carried out to sustain the general circulation. PCPS treatment was discontinued on the 25th day of the admission, but IABP was continued. Finally, he died of multiple organ failure. The autopsy revealed myocardial necrosis with a slight fibrosis and a small amount of lymphocytic infiltration into the ventricular wall, which were compatible with restrictive myocarditis. Moreover, immunohistochemical analysis also showed the presence of viral antigens in cardiac myocytes. This case clearly showed that PCPS and IABP can be beneficial to sustain the general circulation in fulminant myocarditis, but cardiac pumping function failed completely to recover from myocardial damage.

Cardiopulmonary Resuscitation↗
PubMed2001

Idiopathic giant cell granulomatous hypophysitis with hypopituitarism, right abducens nerve paresis and masked diabetes insipidus.

A 38-year-old man presented with headache, fever, and double vision associated with right abducens nerve paresis. He had neither nuchal rigidity nor visual field defect. Laboratory data revealed elevated erythrocyte sedimentation rate (ESR), eosinophilia, and lymphocytic pleocytosis in the cerebrospinal fluid (CSF). Provocation tests of pituitary hormones showed partial hypopituitarism. Magnetic resonance imaging (MRI) revealed swelling of the hypophysis and a mass lesion expanding into the right cavernous sinus. The supplement dose of dexamethasone for hypothalamic hypocortisolism manifested diabetes insipidus. Biopsy, carried out through the transsphenoidal approach, revealed giant cell granuloma. Systemic granulomatous diseases were ruled out, and the lesion was considered to be idiopathic giant cell granulomatous hypophysitis. Right abducens nerve paresis, diabetes insipidus and dysfunction of the anterior lobe were amended by the treatment with prednisolone for 4 months, and findings of the pituitary gland and stalk were normalized. The present case shows that glucocorticoid has an effect on amendment of idiopathic giant cell granulomatous hypophysitis.

Abducens Nerve Diseases↗
PubMed2001

Conjugation with L-Glutamate for in vivo brain drug delivery.

In vitro studies have shown that conjugation of a model compound [p-di(hydroxyethyl)-amino-D-phenylalanine (D-MOD)] with L-Glu can improve D-MOD permeation through the bovine brain microvessel endothelial cell monolayers (Sakaeda et al., 2000). The transport of this D-MOD-L-Glu conjugate is facilitated by the L-Glu transport system. In this paper, we evaluate the in vivo brain delivery of model compounds (i.e. D-MOD, p-nitro-D-phenylalanine (p-nitro-D-Phe), 5,7-dichlorokynurenic acid (DCKA) and D-kyotorphin) and their L-Glu conjugates. DCKA was also conjugated with L-Asp and L-Gln amino acids. The analgesic activities of D-kyotorphin and its L-Glu conjugate were also evaluated. The results showed that the brain-to-plasma concentration ratio of D-MOD-L-Glu was higher than the D-MOD alone; however, the plasma concentration of both compounds were the same. The plasma concentration of p-nitro-D-Phe-L-Glu conjugate was higher than the parent p-nitro-D-Phe; however, the brain-to-plasma concentration ratio of p-nitro-D-Phe was higher than its conjugate. On the other hand, both DCKA and DCKA conjugates have a low brain-to-plasma concentration ratio due to their inability to cross the blood-brain barrier (BBB). The L-Asp and L-Glu conjugates of DCKA have elevated plasma concentrations relative to DCKA; however, the DCKA-L-Gln conjugate has the same plasma concentration as DCKA. For D-kyotorphin, both the parent and the L-Glu conjugate showed similar analgesic activity. In conclusion, conjugation of a non-permeable drug with L-Glu may improve the drug's brain delivery; however, this improvement may depend on the physicochemical and receptor binding properties of the conjugate.

Animals↗
PubMed2001

Beneficial effect of dietary wheat glycolipids on cecum short-chain fatty acid and secondary bile acid profiles in mice.

In the present study, to explore the beneficial effect of dietary galactoglycerolipids on the lower digestive tract environment, male BALB/c mice were fed a 5% wheat glycolipid, fiber-free diet, or the standard AIN diet for 3 wk. The wheat glycolipid composition was digalactosyldiacylglycerol 51.6%, ceramide monohexoside 6.6%, acylated sterylglucoside 3.4%, and other lipids 22.2%, (mostly phospholipids). Cecum and colon weights and colonic crypt depth were significantly greater in the glycolipid-diet mice relative to groups fed the other two diets. Furthermore, in the cecum, propionate. butyrate, and total short-chain fatty acids, concentrations were significantly greater in the glycolipid-diet mice than others were, and correlated with the observed increased lower digestive tract (cecum and colon) weights and colonic crypt depth. The cecal lithocholic acid/deoxycholic acid ratio, a risk index for colorectal cancer, was significantly lower in the glycolipid-diet mice than in the other two dietary groups. These results suggest that the dietary supplementation of plant-source galactoglycerolipids may contribute to improving the lower digestive tract environment.

Animals↗
PubMed2001

[Effects of stimulus intensity on multifocal electroretinograms].

PURPOSE: To investigate origins of responses of the second order kernel components of multifocal electroretinograms (m-ERGs), the influence of stimulus intensities on the waveform were studied. SUBJECTS AND METHODS: M-ERGs were recorded from 20 normal eyes of 14 normal adults using a Visual Evoked Response Imaging System with 19 hexagonal stimulus elements with light intensities of 6.3, 20, 63, 200, or 331 cd/m2. The response densities and implicit times of the first (N1, P1, N2) and the second order kernel components (P1, N1, P2, N2, P3, N3) of the m-ERGs were measured. RESULTS: The components were divided into two groups based on the behavior of the each component to the stimulus intensity change. The first group consisted of all the first order kernel components and P1 and N1 of the second order kernel components whose response densities were significantly larger (p < 0.05) than those of components elicited by stimulus of one grade lower intensity. The second group consisted of N2, P3, and N3 of the second order kernel components whose response densities did not increase when the stimulus intensity was increased from 200 to 331 cd/m2. CONCLUSION: It is probable that in the second order kernel components, the origin of P1, N1, and P2 is different from N2, P3, and N3 because the response to stimulus intensity of the two groups of components was different.

Adult↗
PubMed2001

[Three cases of multiseptate gallbladder].

Multiseptate gallbladder is an extremely rare congenital anomaly. We report three cases of this clinical entity. The third patient, a 70-year-old male who was asymptomatic with this condition, also had a gallbladder carcinoma. The three surgically removed gallbladders had multiple thin septa with a honeycomb appearance. Histologically, the septa contained a muscular layer that was continuous with the gallbladder wall. Furthermore, in the third patient, mucinous cystadenoma with focal carcinomatous change in the epithelium was observed. To our knowledge, this is the first description of a multiseptate gallbladder with carcinoma.

Aged↗
PubMed2001

[A case of pneumonectomy for lung cancer associated with scleroderma].

A 60-year-old female, diagnosed as scleroderma, was referred to our hospital because of symptoms of common cold and abnormal findings on a chest X-ray. The chest X-ray and CT scan revealed a mass in the left upper field, suspected to invade left anterior chest wall. Moreover, fibrotic changes were observed in the lung field. Cytology by bronchofiberscopy showed squamous cell carcinoma. Evaluation of pulmonary function, including unilateral pulmonary artery occlusion test (UPAO), revealed possibility of lung resection. Subsequently, pneumonectomy with combined resection of left 1st rib was performed. Postoperative course was uneventful and she was discharged. She was admitted again four months after the operation with appetite loss and body weight loss. Further examinations revealed arrhythmia, renal failure, pancreatitis and liver metastasis. Her general conditions grew worse and she died five months after the operation. In conclusion, UPAO was a useful method to determine the functional lung resectability for the case with scleroderma. However, effects of surgical stress for the development of scleroderma remain to be elucidated.

Carcinoma, Squamous Cell↗
PubMed2001

[Clinical efficacy of magnetic resonance cholangiopancreatography in the diagnosis of biliary tract diseases].

This study was carried out to clarify the efficacy of magnetic resonance cholangiopancreatography (MRCP) in the diagnosis of biliary tract diseases, Three hundred and eleven patients who underwent MRCP and ERCP during the period from January 1999 to December 1999 at our institution were included in the study. Two gastroenterologists who were blinded to results of direct cholangiography and final diagnoses interpreted MRCP images prospectively. The biliary duct was visualized by MRCP and ERCP in 99.4% and 89.5% of the cases, respectively. The sensitivity, specificity, and accuracy of MRCP in the diagnosis of choledocholithiasis were 95%, 97%, and 97%, respectively. MRCP depicted the presence of strictures with a sensitivity, specificity, and accuracy of 97%, 96%, and 96%, respectively. There were three false-positive cases because of artifacts from arterial compression, The accuracy of MRCP and ERCP in differentiation of benign strictures from malignant ones was 85% and 96%, respectively. Based on these results, it is concluded that MRCP has high capability in visualization of the biliary tree, and in detection of stones and strictures, To avoid over and under-diagnosis, awareness of some pitfalls inherent in, MRCP is important. We suggest that MRCP should be recommended for patients with suspicion of biliary tract diseases in the initial stage of making diagnosis.

Adult↗
PubMed2000

Effect of hypotension severity on hippocampal CA1 neurons in a rat global ischemia model.

Neuronal death in the hippocampal CA1 subregion has been shown to occur in a delayed manner after transient global ischemia. The 2-vessel occlusion model is one of the most frequently used global ischemia paradigms in rodents. Although researchers often fail to induce bilateral delayed CA1 neuronal death, the importance of hypotension severity has not been fully discussed. We induced 10 min of global ischemia with 2-vessel occlusion and various severities of hypotension in rats, and the subsequent neuronal damage and neurogenesis in the hippocampal CA1 pyramidal cell layer were immunohistochemically studied. Neuronal apoptosis after global ischemia was also characterized by terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling (TUNEL). The mean arterial blood pressure of 31-35 mmHg was the most appropriate range of hypotension in this model because of low mortality and consistent bilateral CA1 injury. Most of the neurons in the CA1 pyramidal cell layer lost neuron specific nuclear protein and became TUNEL-positive 3 days after ischemia. There was no evidence of apoptosis or neurogenesis at 7-28 days. There were ischemia-tolerant neurons in the CA1 pyramidal cell layer that survived delayed neurodegeneration, however, further studies are necessary to characterize the property of these neurons.

Animals↗
PubMed2000

Overview of immunotoxicology and current applications to respiratory diseases.

Immunotoxicology has been defined as the study of adverse effects on the immune system resulting directly from environmental, occupational, or therapeutic exposure to chemicals (including drugs), biological materials and, in certain instances, physiological factors, collectively referred to as agents. It encompasses immunosuppression, allergy, autoimmunity and inflammation.

Animals↗
PubMed2000

The cytosolic antioxidant copper/zinc-superoxide dismutase prevents the early release of mitochondrial cytochrome c in ischemic brain after transient focal cerebral ischemia in mice.

Release of mitochondrial cytochrome c into the cytosol is a critical step in apoptosis. We have reported that early release of cytochrome c in vivo occurs after permanent focal cerebral ischemia (FCI) and is mediated by the mitochondrial antioxidant manganese superoxide dismutase (SOD). However, the role of reactive oxygen species produced after ischemia-reperfusion in the mitochondrial apoptosis process is still unknown, although overexpression of copper/zinc-SOD (SOD1), a cytosolic isoenzyme, protects against ischemia-reperfusion. We now hypothesize that the overexpression of SOD1 also prevents apoptosis after FCI. To address this issue, we examined the subcellular distribution of the cytochrome c protein in both wild-type mice and in SOD1 transgenic (Tg) mice after transient FCI. Cytosolic cytochrome c was detected as early as 2 hr after reperfusion, and correspondingly, mitochondrial cytochrome c was significantly reduced after FCI. Cytosolic cytochrome c was significantly lower in the SOD1 Tg mice compared with wild types 2 (p < 0.0001) and 4 (p < 0.05) hr after FCI. Apaf-1, which interacts with cytochrome c and activates caspases, was constitutively expressed in both groups of animals, with no alteration after FCI. Double staining with cytochrome c immunohistochemistry and terminal deoxynucleotidyl transferase-mediated uridine 5'-triphosphate-biotin nick end labeling showed a spatial relationship between cytosolic cytochrome c expression and DNA fragmentation. A significant amount of DNA laddering was detected 24 hr after ischemia and was reduced in SOD1 Tg mice. These data suggest that SOD1 blocks cytosolic release of cytochrome c and could thereby reduce apoptosis after transient FCI.

Animals↗