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T Ishihara

Publications and source records attributed to T Ishihara.

At least 19 recordsLinked to original sources
PubMed2000

Purification of a novel serine proteinase inhibitor from the skeletal muscle of white croaker (Argyrosomus argentatus).

A novel serine proteinase inhibitor has been purified to homogeneity from the skeletal muscle of white croaker (Argyrosomus argentatus). The purification was carried out by ammonium sulfate fractionation, DEAE-Sephacel, heating treatment followed by column chromatographies on SP-Sepharose, Sephadex G-150 and gel-filtration high performance liquid chromatography. The molecular mass of the inhibitor was 55 kDa as estimated by SDS-PAGE and gel filtration. It specifically inhibited a myofibril-bound serine proteinase (MBSP) isolated from the skeletal muscle of lizard fish (Saurida wanieso). No inhibition, however, was detected toward other serine proteinases such as bovine trypsin, bovine chymotrypsin and a myofibril-bound serine proteinase from carp (Cyprinus carpio) muscle. Interestingly, the sequences of tryptic digested peptide fragments of MBSPI revealed high identity to that of porcine phosphoglucose isomerase (PGI) (76%) and other PGIs. Furthermore, purified MBSPI exhibits PGI activity, suggesting the inhibitor is a protein closely related to PGI. When rabbit muscle PGI was investigated, it also specifically suppressed the activity of MBSP. It thus strongly suggests that MBSPI is actually PGI and conversely, PGI is a specific inhibitor toward myofibril-bound serine proteinase(s).

Amino Acid Sequence↗
PubMed2000

IL-18 prevents the development of chronic graft-versus-host disease in mice.

The development of chronic graft-versus-host disease (GVHD), which is induced by the transfer of DBA/2 spleen cells into (C57BL/6 x DBA/2)F1 (BDF1) mice, is closely related to diminished donor anti-host CTL activity and host B cell hyperactivation. Therefore, an approach which activates donor CD8+ T cells or suppresses donor CD4+ T cell-host B cell interaction may have clinical utility in the treatment of chronic GVHD. We have previously demonstrated that IL-18 induces the development of naive CD8+ T cells into type I effector cells in DBA/2 anti-BDF1 MLC. In this paper we examined the effect of IL-18 administration on the development of chronic GVHD in mice. The treatment was started before or after the onset of clinical evidence of the disease. Regardless of the treatment schedule, IL-18 significantly decreased immunological parameters indicative of chronic GVHD, such as elevated serum IgG antinuclear Abs, IgG1, and IgE levels, and host B cell numbers and their activation. Importantly, IL-18-treated mice did not show the same acute GVHD-like symptoms reported for IL-12 treatment, because there was no weight loss, death, or severe immunodeficiency as indicated by a decrease in IL-2 and IFN-gamma production by Con A-stimulated spleen cells. In contrast, IL-18 treatment partially but significantly restored the production of these cytokines. Data further suggested that these IL-18-mediated therapeutic effects may be due to the induction of donor CD8+ CTL, the decrease in donor CD4+ T cell numbers, and a down-regulation of host B cell MHC class II expression. Thus, our results suggest that IL-18 has beneficial effects in the prevention and treatment of chronic GVHD.

Acute Disease↗
PubMed2000

Cenozoic motion between East and West Antarctica

The West Antarctic rift system is the result of late Mesozoic and Cenozoic extension between East and West Antarctica, and represents one of the largest active continental rift systems on Earth. But the timing and magnitude of the plate motions leading to the development of this rift system remain poorly known, because of a lack of magnetic anomaly and fracture zone constraints on seafloor spreading. Here we report on magnetic data, gravity data and swath bathymetry collected in several areas of the south Tasman Sea and northern Ross Sea. These results enable us to calculate mid-Cenozoic rotation parameters for East and West Antarctica. These rotations show that there was roughly 180 km of separation in the western Ross Sea embayment in Eocene and Oligocene time. This episode of extension provides a tectonic setting for several significant Cenozoic tectonic events in the Ross Sea embayment including the uplift of the Transantarctic Mountains and the deposition of large thicknesses of Oligocene sediments. Inclusion of this East-West Antarctic motion in the plate circuit linking the Australia, Antarctic and Pacific plates removes a puzzling gap between the Lord Howe rise and Campbell plateau found in previous early Tertiary reconstructions of the New Zealand region. Determination of this East-West Antarctic motion also resolves a long standing controversy regarding the contribution of deformation in this region to the global plate circuit linking the Pacific to the rest of the world.

Journal Article↗
PubMed2000

Association between the expression of mast cell chymase and intraperitoneal adhesion formation in mice.

BACKGROUND: Adhesion formation is a major source of postoperative morbidity and mortality. Mast cells and their major protease, chymase, have been shown to participate in the healing process as well as in tissue remodeling. We aimed to identify the role of mast cells in intraperitoneal adhesion formation and to assess whether there is an association between the expression of mast cell chymase and adhesion formation. MATERIALS AND METHODS: Both mast cell-deficient W/W(V) mice and congenic +/+ mice received a standardized lesion produced by cecal scraping and the application of 95% ethanol. Adhesions were assessed blindly 1 week later using a standardized scale. In addition, histamine content, mast cell numbers, and chymase activity in cecum as well as at the healing sites were evaluated before and 7 days after surgical injury. RESULTS: A significant reduction in adhesion formation was seen in mast cell-deficient W/W(V) mice (P < 0.05). In the normal cecum, histamine content did not significantly differ between W/W(V) and +/+ mice. Chymase activity in cecum was detected in control +/+ mice, but not in W/W(V) mice. Mast cell numbers and chymase activity levels at the healing sites of +/+ mice were significantly increased 7 days after surgery. CONCLUSIONS: Our results indicate that mast cells contribute to intraperitoneal adhesion formation in mice, and suggest that chymase originating from mast cells is important in the development of adhesions.

Animals↗
PubMed2000

Axonopathy and amyotrophy in mice transgenic for human four-repeat tau protein.

Coding region and intronic mutations in the tau gene cause frontotemporal dementia and parkinsonism linked to chromosome 17. Some of these mutations lead to an overproduction of tau isoforms with four microtubule-binding repeats. Here we have expressed the longest four-repeat human brain tau isoform in transgenic mice under the control of the murine Thy1 promoter. Transgenic mice aged 3 weeks to 25 months overexpressed human tau protein in nerve cells of brain and spinal cord. Numerous abnormal, tau-immunoreactive nerve cell bodies and dendrites were seen. In addition, large numbers of pathologically enlarged axons containing neurofilament- and tau-immunoreactive spheroids were present, especially in spinal cord. Signs of Wallerian degeneration and neurogenic muscle atrophy were observed. When motor function was tested, transgenic mice showed signs of muscle weakness. Taken together, these findings demonstrate that overexpression of human four-repeat tau leads to a central and peripheral axonopathy that results in nerve cell dysfunction and amyotrophy.

Animals↗
PubMed2000

Long-term outcome of endoscopic papillotomy for choledocholithiasis with cholecystolithiasis.

BACKGROUND: Although endoscopic papillotomy is now considered established treatment for choledocholithiasis, therapeutic results of endoscopic papillotomy alone without subsequent cholecystectomy in patients with cholecystolithiasis have not been well evaluated. The aim of this study was to assess the long-term outcome of endoscopic papillotomy for these patients. METHODS: Patients admitted with choledocholithiasis and cholecystolithiasis from 1976 to 1993 were studied retrospectively. Of 385 patients in whom the bile duct was cleared by endoscopic papillotomy and endoscopic stone extraction, 371 patients (195 men and 176 women; mean age 65.4 years) were followed. Predisposing risk factors for late complications were analyzed. RESULTS: The mean duration of follow-up was 7.7 years. Cholecystitis and recurrence of choledocholithiasis as late complications occurred in 22 cases (5.9%) and 36 cases (9.7%), respectively. Cholecystitis, including 1 severe case, resolved with conservative treatment. Recurrent choledocholithiasis was successfully treated endoscopically except in 1 case. No significant risk factors were identified for cholecystitis. The presence of pneumobilia (p = 0.0016) and the need for lithotripsy (p = 0.0342) were found to be significant risk factors for the recurrence of choledocholithiasis. CONCLUSIONS: Long-term outcome of endoscopic papillotomy in patients with choledocholithiasis and cholecystolithiasis was found to be relatively favorable. Cholecystectomy after endoscopic papillotomy is not always necessary in the management of cholecystolithiasis.

Aged↗
PubMed2000

Pathogenic factors of glucose intolerance in obese Japanese adolescents with type 2 diabetes.

We attempted to identify the pathogenic factors involved in the progression to type 2 diabetes in obese Japanese adolescents. Subjects included 18 nondiabetic obese adolescents, 12 obese adolescents with type 2 diabetes on diet therapy, 10 obese adolescents with type 2 diabetes manifesting ketosis at onset or with a history of treatment with hypoglycemic agents, and 26 non-obese adolescent control subjects. The first-phase insulin response (FPIR), glucose disappearance constant (Kg), glucose effectiveness (Sg), and insulin sensitivity (S(I)) were obtained using an insulin-modified frequently sampled intravenous glucose tolerance test (FSIGT) and a minimal model analysis. The disposition index (DI, by FPIR x S(I)) was determined to assess any endogenous insulin effect. The results showed that Kg was decreased significantly (P = .0006) with the progression to severe diabetes in the obese groups. Although S(I) and Sg did not differ significantly among the 3 obese groups, both parameters were significantly lower in each obese group versus the non-obese controls. As a result of the significant decrease in FPIR (P < .0001), the DI decreased (P = .0006) with the progression to severe diabetes in the obese groups. In conclusion, an early manifestation of type 2 diabetes with occasional ketosis at onset may result from beta-cell dysfunction to glucose stimulation. This finding is demonstrated by the relatively low FPIR to decreased S(I) in obese Japanese adolescents, as well as the low Sg as a synergic role in glucose intolerance. The present findings from a Japanese population for pathogenic factors aside from obesity may help us to gain a better understanding of the progression to adolescent, early-onset, obese type 2 diabetes and its severity.

Adolescent↗
PubMed2000

Identification of a myofibril-bound serine proteinase (MBSP) in the skeletal muscle of lizard fish Saurida wanieso which specifically cleaves the arginine site.

A myofibril-bound serine proteinase (MBSP) from the skeletal muscle of lizard fish (Saurida wanieso) was purified to homogeneity by a heating treatment followed by a series of column chromatographies on DEAE-Sephacel, Sephacryl S-200, Q-Sepharose, Hydroxyapatite and Benzamidine-Sepharose 6B, and characterized enzymatically. On SDS-poly-acrylamide gel electrophoresis (SDS-PAGE), the purified enzyme showed a band with molecular mass of approximately 29 kDa under reducing conditions, while 60 kDa under non-reducing conditions. The optimum temperature of the enzyme was 50 degrees C using t-butyloxycarbonyl-Phe-Ser-Arg-4-methylcoumaryl-7-amide (Boc-Phe-Ser-Arg-MCA) as a substrate. Substrate specificity analysis both using MCA-substrates and peptides showed that MBSP specifically cleaved at the carboxyl side of the arginine residue. Inhibitor susceptibility analysis revealed that MBSP was inhibited effectively by Pefabloc SC, soybean trypsin inhibitor (STI) and aprotinin, indicating the characteristic of a serine proteinase. When myofibril was incubated with the enzyme, it optically degraded myosin heavy chain at 55-60 degrees C, while alpha-actinin and actin were not at all hydrolyzed as detected by immunoblotting. The N-terminal amino acid sequence of MBSP was partially determined as IVGGAEXVPY- and was very homologous to other serine proteases.

Amino Acid Motifs↗
PubMed2000

Temporal profile of CRE DNA-binding activity in the rat hippocampus following a kindling stimulation.

This study was designed to establish a role for cAMP-responsive element (CRE) binding protein (CREB) in signal transduction cascade in the hippocampus associated with kindling. Male Sprague-Dawley rats were kindled from the left amygdala until they exhibited Racine's class 5 generalized seizures [Racine (1972). EMBO J. 11, 3337-3346] Nuclear proteins were extracted from dorsal hippocampi obtained from 0 to 24 h after final kindling stimulation. From these, we evaluated the temporal pattern of CRE DNA-binding activity by use of a gel mobility-shift assay with a 32P-labeled CREB oligonucleotide probe. CRE-binding activity in the hippocampus was enhanced significantly at 2 h and returned to baseline level within 4 h after the stimulation. Our results suggest that CREB may be involved in the hippocampal signal transduction pathway of rats activated in response to a kindling stimulation to the amygdala. However, the transient elevation of CRE-binding activity following a seizure in a kindled animal also suggests that persistent activation of CREB may not be required for maintenance of the kindling phenomenon.

Animals↗
PubMed2000

Identification and characterization of the high-affinity choline transporter.

In cholinergic neurons, high-affinity choline uptake in presynaptic terminals is the rate-limiting step in acetylcholine synthesis. Using information provided by the Caenorhabditis elegans Genome Project, we cloned a cDNA encoding the high-affinity choline transporter from C. elegans (cho-1). We subsequently used this clone to isolate the corresponding cDNA from rat (CHT1). CHT1 is not homologous to neurotransmitter transporters, but is homologous to members of the Na+-dependent glucose transporter family. Expression of CHT1 mRNA is restricted to cholinergic neurons. The characteristics of CHT1-mediated choline uptake essentially match those of high-affinity choline uptake in rat brain synaptosomes.

Amino Acid Sequence↗
PubMed2000

Peroral pancreatoscopy in the diagnosis of mucin-producing tumors of the pancreas.

BACKGROUND: Mucin-producing tumor of the pancreas is an increasingly recognized clinical entity. However, the differentiation of benign from malignant mucin-producing tumors of the pancreas is challenging. Peroral pancreatoscopy as recently developed may have potential for the diagnosis of mucin-producing tumors of the pancreas. METHODS: The subjects were 41 patients with clinically diagnosed mucin-producing tumors of the pancreas, 40 of whom underwent surgical resection. Autopsy findings were available in another patient with unresectable disease. Histologically, hyperplasia was identified in 3 patients, mildly atypical adenoma in 11, severely atypical adenoma in 16, and adenocarcinoma in 11. Peroral pancreatoscopy was performed before surgery or pathologic examination. The findings were retrospectively evaluated and compared with the histopathologic diagnosis. RESULTS: Pancreatoscopic observation was successful in 30 patients (73.2%). Elevated lesions were identified in 22 (73.3%). Villous or vegetative elevations and red color markings were frequently found in severely atypical adenoma or adenocarcinoma. Tumor location (main or branch duct type) did not correlate with survival after resection. Partial resection was performed in 7 of 30 patients with nonmalignant tumors and resulted in favorable outcomes. CONCLUSION: Peroral pancreatoscopy can be used to differentiate benign mucin-producing tumors of the pancreas (hyperplasia and mildly atypical adenoma) from the more dysplastic lesions (severely atypical adenoma and adenocarcinoma) and may provide useful information for determining the type of surgery to be performed.

Adenocarcinoma↗
PubMed2000

Effect of imidapril in dipper and nondipper hypertensive patients: comparison between morning and evening administration.

The purpose of the study was to identify differences in the patterns of efficacy and duration of effects of imidapril administered at different times of the day (morning versus evening) in dipper and nondipper hypertensive patients. Twenty patients with untreated hypertension were classified into two groups: dippers (n = 9) and nondippers (n = 11). Imidapril (10 mg) was given at 07:00 or 18:00 for 4 weeks in a crossover fashion. Blood pressure (BP) and heart rate (HR) were monitored before and after morning and evening treatment every 30 min for 48h by ambulatory BP monitoring (ABPM). In dipper hypertension, the mean 48h BP was reduced with both doses. The decrease in the diurnal BP was stronger when the drug was administered in the evening than morning, but without significant difference. In nondipper hypertension, the systolic BP decreased at night with both doses, but the extent of the nocturnal reduction in systolic BP was greater after morning therapy. There were no significant differences in the decrease in BP during the day or night between the morning and evening administrations. When imidapril was administered in the morning, its serum concentration reached a maximum at 16:00, and when the drug was administered in the evening, it reached a maximum at 6:00. In dipper hypertension, the time taken for the blood concentration of imidapril to reach a maximum changed depending on its time of administration, and the time when the maximum antihypertensive effect of the drug appeared was different. In nondipper hypertension, decreases in the BP were confirmed at night regardless of the time of administration; this might be caused by angiotensin converting enzyme (ACE) inhibitors effectively blocking the BP from increasing by activating the parasympathetic nervous system. Therefore, when assessing the effectiveness of antihypertensive agents, factors such as the various patterns of BP before therapy and administration time must be considered.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

Chlamydia pneumoniae in atherosclerotic and nonatherosclerotic tissue.

The positivity rate and localization of Chlamydia pneumoniae were investigated in atherosclerotic and nonatherosclerotic tissues by immunohistochemistry, polymerase chain reaction, and cell culture. In total, 67 atheromatous plaques from Japanese symptomatic patients and 110 nonatherosclerotic tissues and organs were evaluated. Of these, 62% of atherosclerotic plaques from symptomatic patients were infected with C. pneumoniae compared with just 2% of nonatherosclerotic tissues. Immunohistochemically stained C. pneumoniae were found most often in smooth muscle cells, less often in macrophages, and in a few endothelial cells.

Adult↗
PubMed2000

Acute effects of a single low oral dose of pimobendan on left ventricular systolic and diastolic function in patients with congestive heart failure.

A recent long-term multicenter trial has shown that pimobendan is more effective when administered in low doses. However, no data are available concerning the effect of a low dose of pimobendan on the systolic and diastolic pressure-volume relations in patients with heart failure. Therefore we examined the effects of a single low dose of oral pimobendan, a calcium sensitizer, on systolic and diastolic hemodynamics in patients with cardiomyopathy and congestive heart failure. We measured the left ventricular (LV) pressure-volume relations using a conductance catheter with a micromanometer tip in 10 patients with chronic congestive heart failure resulting from idiopathic cardiomyopathy before and 45 and 90 min after administration of a single oral dose of 2.5 mg of pimobendan. End-systolic elastance was used as an index of LV contractility and was measured during transient occlusion of the inferior vena cava. End-systolic elastance increased significantly by 25% at 45 min (p < 0.05) and by 55% at 90 min (p < 0.01) without an increase in myocardial oxygen consumption. The inotropic effect was accompanied by improved ventriculoarterial coupling. This effect was attenuated in patients with severely impaired myocardial contractility. LV relaxation, assessed by the time constant of isovolumic pressure decay (T(1/2)), was significantly shortened at 90 min (from 47.7 +/- 1.9 to 41.2 +/- 1.7 ms; p < 0.01), although it remained unchanged at 45 min. The diastolic pressure-volume relation showed a leftward and downward shift in all patients. These results indicate that low-dose oral pimobendan had favorable short-term inotropic and lusitropic effects in patients with congestive heart failure caused by idiopathic dilated cardiomyopathy, and may thus be a useful alternative to traditional agents. Further study in a large-scale trial is merited.

Administration, Oral↗
PubMed2000

Synthesis of regioselectively protected forms of cytidine based on enzyme-catalyzed deacetylation as the key step.

N4-Acetylcytidine (77%) and 2',3'-O, N4-triacetylcytidine (95%) were obtained from the hydrolysis of a common precursor, the peracetylated form of cytidine with Aspergillus niger lipase (Amano A) and Burkholderia cepacia esterase (SC esterase S), respectively, under very mild conditions. The experimental procedure for the conversion of triacetylcytidine to a corresponding phosphoramidite (82%), an intermediate for sugar nucleotide synthesis, is also elaborated.

Acetylation↗
PubMed2000

A role of free insulin-like growth factor-I in dawn phenomenon in children and adolescents with type 1 diabetes mellitus.

It has been hypothesized that a decreased amount of the free form of insulin-like growth factor-I (fIGF-I) results in morning hyperglycemia in patients with type 1 diabetes mellitus. In this study, we attempted to clarify the role of fIGF-I in relation to total IGF-I (tIGF-I) and its related peptides or proteins in type 1 diabetes. Forty-seven patients with type 1 diabetes, mean age 13.7 years, were evaluated. Blood samples were obtained for the measurement of BG at 0200, 0400 and 0700, and of insulin, total IGF-I (tIGF-I), fIGF-I, IGFBP-1 and IGFBP-3 at 0700. The SD scores (SDS) were determined for the levels of tIGF-I, flGF-I, IGFBP-1 and IGFBP-3 by using Japanese reference data. The morning increase in BG (deltaBG(4-7)) correlated significantly with fIGF-I SDS (r=-0.352, p=0.0152) and IGFBP-1 SDS (r=0.438, p=0.0021), but did not correlate significantly with the fIGF-I level itself or the ratio of fIGF-I to tIGF-I (f/t IGF-I ratio). Hereupon, the f/t IGF-I ratio correlated positively with fIGF-I SDS (r=0.541, p=0.0003). The mean+/-SD in the f/t IGF-I ratio was 0.94+/-0.43%, and that in fIGF-I SDS was -0.50+/-1.32. The level of IGFBP-I SDS correlated negatively with fIGF-I SDS (r=-0.472, p=0.0008) and insulin (r=-0.365, p=0.0116). We suggest that the morning level of fIGF-I SDS, rather than the fIGF-I level itself, may be a useful marker of decreased insulin-like bioactivity in the dawn phenomenon in type 1 diabetes mellitus.

Adolescent↗
PubMed2000

Successfully treated complete atrioventricular block with corticosteroid in a patient with cardiac sarcoidosis: usefulness of gallium-67 and thallium-201 scintigraphy.

A 71-year-old male with sarcoidosis was followed for 6 years without steroid therapy. He was admitted because of complete atrioventricular block. Chest X-ray showed hilar lymphadenopathy. Echocardiogram showed mild left ventricular hypertrophy without local wall thinning. Cardiac sarcoidosis was diagnosed by a defect of Thallium-201 (Tl-201) imaging and abnormal uptake of Gallium-67 (Ga-67). After the start of corticosteroid therapy, complete atrioventricular block was recovered. Abnormal uptake of Ga-67 was improved. Tl-201 and Ga-67 are useful to diagnose cardiac sarcoidosis, to evaluate the lesion of cardiac involvement and to estimate the efficacy of corticosteroid therapy.

Aged↗