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Biomedical subjects

M Tominaga

Publications and source records attributed to M Tominaga.

At least 37 records · Page 2Linked to original sources
PubMed2001

Characterization of platelet-derived growth factor-induced p38 mitogen-activated protein kinase activation in vascular smooth muscle cells.

BACKGROUND: The mitogen-activated protein (MAP) kinase super-family plays a crucial role in cell growth and differentiation and even in programmed cell death in response to diverse extracellular stimuli. The platelet-derived growth factor (PDGF)-BB is well known to promote the proliferation of vascular smooth muscle cells (VSMC) via extracellular-regulated protein kinases (ERKs), leading to the development of cardiovascular diseases. However, it has not yet been clarified whether PDGFs that include other isoforms can activate the other parallel signal transduction pathways, c-jun NH2-terminal protein kinase (JNK) and p38 MAP kinase (p38), in VSMC. In this study, we investigated the effect of PDGFs on p38 activation in cultured rat VSMC. MATERIALS AND METHODS: After stimulation by PDGFs with SB-203580 or PD-98059, the cells were solubilized, and the expressions of MAP kinases, MAP kinase kinases (MKKs), phosphorylated DNA-binding proteins, and cyclooxigenases (COXs) were examined by immunoblot analysis. RESULTS: PDGFs activated p38 phosphorylation dose-dependently, and the phosphorylations were specifically inhibited by SB-203580 but not by PD-98059. PDGFs also activated the phosphorylation of MKK 3/MKK 6 but not that of either stress-activated protein kinase/ERK kinase or JNK. PDGFs affected the activation of a cyclic AMP response-element binding protein, which was inhibited by SB-203580. However, the activating transcription factor-2 was not activated by PDGFs. Interestingly, the stimulation of PDGFs for 72 h enhanced the level of COX-2, and these levels were decreased by SB-203580. CONCLUSION: These results have clarified that PDGFs activate the p38 cascade via an MKK 3/6 pathway, independently of the ERK cascade, and subsequently regulate the level of COX-2 in rat VSMC, providing that PDGFs influence the inflammatory process in the vascular wall.

Activating Transcription Factor 2↗
PubMed2001

Alterations of nitric oxide and monoamines in the brain of the EL mouse treated with phenobarbital and zonisamide.

The effects of phenobarbital (PB; doses, 5, 10, and 25 mg/kg, intraperitoneally (i.p.)) and zonisamide (ZNS; doses, 30, 75, and 150 mg/kg, i.p.) on nitric oxide (NO) production, and those of coadministration of PB (5 mg/kg, i.p.) and ZNS (75 mg/kg, i.p.) on monoamines in the brain of the seizure-susceptible EL mouse were investigated. Nitric oxide production was obtained by measuring the combined level of nitrite plus nitrate (NOx). Zonisamide and PB dose-dependently suppressed the seizure of the EL mouse, and coadministration of PB (5 mg/kg) and ZNS (75 mg/kg) induced a greater degree of seizure suppression than treatment with ZNS or PB alone. Although PB (5 mg/kg) had no effect on brain NOx levels, ZNS (150 mg/kg) and coadministration of ZNS (75 mg/kg) and PB (5 mg/kg) decreased NOx levels significantly. Phenobarbital (5 mg/kg) did not influence monoamines, while coadministration of PB (5 mg/kg) and ZNS (75 mg/kg) decreased dihydroxyphenylacetic acid and increased 5-HT concentrations. The effect of the coadministration of two drugs on monoamines were similar to that of ZNS alone. These results suggest that one of the anticonvulsant effects of coadministration of PB and ZNS may be caused by changes in NOx levels.

Animals↗
PubMed2001

Influences of caffeine to nitric oxide production and zonisamide concentration in the brain of seizure-susceptible EL mice.

To investigate changes of nitric oxide (NO) productions and zonisamide (ZNS) concentrations in the brain of seizure-susceptible EL mice given caffeine orally, mice were given caffeine (600 microg/mL) solution ad libitum as a drinking fluid for 1-3 weeks. Nitric oxide production in the brain was determined by measuring levels of nitrite plus nitrate (NOx). The brain NOx levels of mice treated with caffeine for 3 weeks were significantly higher than the control. Seizures in mice treated with caffeine for 2 and 3 weeks were not suppressed by ZNS at a dose of 75 mg/kg. Serum ZNS concentrations of mice with caffeine intake for 1-3 weeks were higher than in untreated mice. Conversely, brain ZNS concentrations of mice with caffeine intake for the same periods were significantly lower than in untreated mice. These results suggested that caffeine influenced brain NO production and ZNS concentrations in the seizure susceptibility of EL mice.

Animals↗
PubMed2001

Comparison of lymphocyte depletion and clinical effectiveness on filtration leukocytapheresis in patients with rheumatoid arthritis.

We evaluated the relationship between the clinical benefit of filtration leukocytapheresis (LCP) and the number of removed leukocytes in patients with rheumatoid arthritis (RA). LCP was performed in 31 drug-resistant RA patients. LCP was carried out 3 times with 1 week separating each session. Assessment of RA before and after LCP showed a substantial and rapid improvement in tender joint counts, swollen joint counts, and patients' and physicians' assessments. Careful analysis indicated that 19 of 31 patients with RA showed > or = 20% improvement following LCP therapy. The number of leukocytes in the peripheral blood significantly decreased during each session of LCP. However, there was no significant decrease in the number of circulating blood cells during the study period. No adverse reactions or complications were noted. There was no significant difference in any indices of clinical activity and the removal rates of leukocytes between responders and nonresponders. The total numbers of removed lymphocytes in responders were significantly higher than those in nonresponders (responders 64.1 x 10(8) versus nonresponders 50.7 x10(8), p < 0.05). The relationship between clinical effectiveness and the number of removed granulocytes and monocytes was not statistically significant. Our results suggest that filtration LCP to remove leukocytes from the peripheral blood, especially lymphocytes, exerts an immunomodulatory effect in patients with RA.

Adult↗
PubMed2001

Characterization of an inhibitory effect of pioglitazone on balloon-injured vascular smooth muscle cell growth.

This study investigates whether pioglitazone could suppress an atherogenic process such as balloon-injured carotid intimal thickening and the proliferation of vascular smooth muscle cells (VSMC). We first examined the effect of pioglitazone to determine whether it could suppress intimal thickening induced by balloon catheterization in Sprague-Dawley rats. After 14 days postcatheterization in the left common carotid artery, the neointimal layers were completely occupied by proliferated VSMC, and the area ratio of neointima to media treated with 10 mg/kg/d of pioglitazone was significantly decreased to 57%. Next, we evaluated the effect of pioglitazone on the proliferation of rat cultured VSMC. Piogliotazone dose-dependently decreased the values of DNA synthesis, total cellular protein content, phosphorylations of extracellular signal-regulated protein kinase 1/2 and mitogen-activated protein kinase kinase 1/2, and proliferative cell nuclear antigen in VSMC. Pioglitazone also inhibited the phosphorylation of Pyk2. We conclude that pioglitazone itself could be effective for suppressing the growth of VSMC and consequent carotid intimal thickening.

Animals↗
PubMed2001

Differentiation stages of eosinophils characterized by hyaluronic acid binding via CD44 and responsiveness to stimuli.

To characterize interleukin (IL)-5-induced eosinophils, we examined the expression of CD44, very late antigen (VLA)-4, and the IL-5 receptor alpha chain, as well as the levels of eosinophil peroxidase and the generation of superoxide. Eosinophils were prepared from IL-5-transgenic mice, then characterized using electron microscopy to determine their responses to stimuli. Whereas CD44 densities remained almost constant, the level of VLA-4 increased in parallel with eosinophil maturation. Although a subset of IL-5-induced eosinophils with high side scatter recovered from bone marrow and rare ones found in blood recognized hyaluronic acid (HA), most did not have this property. Bone marrow eosinophils with high side scatter and lower density contained eosinophil peroxidase, not only in granules, but also in membranous structures for 30% of this population. This population developed HA-binding ability in response to IL-3, IL-4, IL-5, granulocyte-macrophage colony-stimulating factor, macrophage inflammatory protein (MIP)-2, monocyte chemotactic protein (MCP)-1, eotaxin, nerve growth factor (NGF), and opsonized zymosan (OZ). Peripheral blood eosinophils acquired HA-binding ability in response to the same stimuli, but their responses were less than those of bone marrow eosinophils with high levels of side scatter. However, splenic eosinophils did not respond to these stimuli. Although peripheral blood eosinophils did not proliferate when stimulated by IL-5, these were the only cells that released eosinophil peroxidase in response to IL-4, MIP-2, MCP-1, eotaxin, NGF, and OZ. With the exception of a subset of bone marrow eosinophils, the ability to acquire HA binding, but not the ability to generate superoxide, correlated with eosinophil peroxidase activity and major basic protein accumulation in the granules of maturing cells.

Animals↗
PubMed2001

Guard-cell chloroplasts provide ATP required for H(+) pumping in the plasma membrane and stomatal opening.

To elucidate the role of guard-cell chloroplasts (GCCs) in stomatal movement, we investigated the effects of oligomycin, an inhibitor of oxidative phosphorylation, and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), an inhibitor of photosystem II, on fusicoccin (FC)-induced H(+) pumping and stomatal opening. FC was found to induce H(+ )pumping in guard-cell protoplasts (GCPs) from Vicia faba and stomatal opening in the epidermis of Commelina benghalensis; and, red light (RL) slightly stimulated these responses. Oligomycin strongly inhibited the pumping and stomatal opening in the dark. RL partially reversed the inhibitions, and DCMU decreased the effect of RL. FC activated the plasma membrane H(+)-ATPase (EC 3.6.1.35) in GCPs similarly irrespective of these treatments, indicating that the H(+)-ATPase activity was not the limiting step in H(+) pumping. Oligomycin significantly decreased the ATP content in GCPs in the dark. RL partially reversed this effect, and DCMU eliminated the effect of RL. A significant part of the ATP produced by photophosphorylation to H(+) pumping was indicated under RL. These results suggest that GCCs supply ATP to the cytosol under RL, and that the ATP is utilized by the plasma membrane H(+)-ATPase for H(+) pumping.

Cell Membrane↗
PubMed2001

Possible role of heat shock protein 60 in reducing ischemic-reperfusion injury in canine pancreas grafts after preservation by the two-layer method.

INTRODUCTION: Recently, results of the clinical application of the two-layer method have shown the morphologic quality of the human pancreas grafts after reperfusion to be excellent, although ischemia-reperfusion injury is related to early graft loss in pancreas transplantation. However, some reports have indicated that heat shock proteins (HSPs) have important functions in response to the stress-related events. AIM: To examine whether the two-layer method reduced ischemia-reperfusion injury in a canine pancreas autotransplantation model by investigating the expression of HSPs. METHODOLOGY: There were three experimental groups in which dogs received segmental autografts after preservation by the two-layer method using University of Wisconsin solution (UW) (group 1), simple storage in UW (group 2) for 24 hours, or no preservation (group 3). RESULTS: In group 1, pancreatic tissue perfusions were high, and pancreatic exocrine functions were well preserved after 1, 2, and 4 hours of reperfusion with low incidence of graft pancreatitis or vessel thrombosis compared with that in group 2. Moreover, ATP rapidly recovered, and HSP 60 was strongly enhanced after reperfusion in group 1. On the other hand, ATP recovery and the enhancement of HSP 60 were weak after reperfusion in group 2. CONCLUSION: The two-layer method reduced ischemia-reperfusion injury compared with UW simple storage in canine pancreas autotransplantation with a strong expression of HSP 60.

Adenosine Triphosphate↗
PubMed2001

Fmoc-POAC: [(9-fluorenylmethyloxycarbonyl)-2,2,5,5-tetramethylpyrrolidine-N-oxyl-3-amino-4-carboxylic acid]: a novel protected spin labeled beta-amino acid for peptide and protein chemistry.

The stable free radical 2,2,6,6-tetramethylpiperidine-N-oxyl-4-amino-4-carboxylic acid (TOAC) is the only spin labeled amino acid that has been used to date to successfully label peptide sequences for structural studies. However, severe difficulty in coupling the subsequent amino acid has been the most serious shortcoming of this paramagnetic marker. This problem stems from the low nucleophilicity of TOAC's amine group towards the acylation reaction during peptide chain elongation. The present report introduces the alternative beta-amino acid 2,2,5,5-tetramethylpyrrolidine-N-oxyl-3-amino-4-carboxylic acid (POAC), potentially useful in peptide and protein chemistry. Investigations aimed at addressing the stereochemistry of this cyclic molecule through X-ray diffraction measurements of crystalline and bulk samples revealed that it consists only of the trans conformer. The 9-fluorenylmethyloxycarbonyl group (Fmoc) was chosen for temporary protection of the POAC amine function, allowing insertion of the probe at any position in a peptide sequence. The vasoactive octapeptide angiotensin II (All, DRVYIHPF) was synthesized by replacing Pro7 with POAC. The reaction of Fmoc-POAC with the peptidyl-resin occurred smoothly, and the coupling of the subsequent amino acid showed a much faster reaction when compared with TOAC. POAC7-AII was obtained in good yield, demonstrating that, in addition to TOAC, POAC is a convenient amino acid for the synthesis of spin labeled peptide analogues. The present findings open the possibility of a wide range of chemical and biological applications for this novel beta-amino acid derivative, including structural investigations involving its differentiated bend-inducing characteristics.

Amino Acids↗
PubMed2001

Evaluation of the trifluoromethanosulfonic acid/trifluoroacetic acid/thioanisole cleavage procedure for application in solid-phase peptide synthesis.

As an extension of our investigation of peptidyl-resin linkage stability towards different cleavage procedures used in the solid-phase peptide synthesis (SPPS) technique, the present paper evaluated the trifluoromethanesulfonic acid (TFMSA)/trifluoroacetic acid (TFA)/thioanisole method, varying the type of resin (benzhydrylamine-resin, BHAR; methylbenzhydrylamine-resin, MBHAR and 4-(oxymethyl)-phenylacetamidomethyl-resin, PAMR) and peptide resin-bound residue (Gly and Phe). The vasoactive angiotensin II (AII, DRVYIHPF) and its [Gly8]-AII analogue linked to those resins used routinely in tert-butyloxycarbonyl (Boc)-SPPS chemistry were submitted comparatively to a time course study towards TFMSA/TFA cleavage. At 0 degrees C, [Gly8]-AII was completely removed from all resins in less than 6 h, but the hydrophobic Phe8 moiety-containing AII sequence was only partially cleaved (not more than 15%) from BHAR or MBHAR in this period. At 25 degrees C, [Gly8]-AII cleavage time decreased to less than 2 h irrespective of the solid support, and quantitative removal of AII from PAMR and MBHAR occurred in less than 3 h. However, about 10-15 h seemed to be necessary for cleavage of AII from BHAR, and in this extended cleavage reaction a significant increase in peptide degradation rate was observed. Regardless of the cleavage temperature used, the decreasing order of acid stability measured for resins was BHAR>MBHAR>PAMR. Collectively, these findings demonstrated the feasibility of applying TFMSA/TFA solution as a substitute for anhydrous HF at the cleavage step in Boc-SPPS methodology. Care should be taken however, as the cleavage efficacy depends on multiple factors including the resin, peptide sequence, the time and temperature of reaction.

Amino Acids↗
PubMed2001

Digested bacterial cell powder (DBCP) as a source of reduced-form folates for pigs: use of a trimethoprim-resistant strain and the bioavailability of folates in DBCP.

The production of digested bacterial cell powder (DBCP) as a source of reduced-form folates for pigs was studied. Trimethoprim-resistant mutants of Brevibacterium lactofermentum ATCC 13869 accumulated a significantly higher amount of the reduced form of folate in the cells than the wild-type strain. DBCPs were prepared from the resistant mutant strain and the wild-type strain. The utilization of the reduced-form of folate in DBCP was evaluated by measuring the plasma folate level after orally administering DBCP to Göttingen minipigs. The folates in both DBCPs proved to have equally high bioavailability in the pigs.

Animals↗
PubMed2001

Platelet-derived growth factor BB-induced p38 mitogen-activated protein kinase activation causes cell growth, but not apoptosis, in vascular smooth muscle cells.

The aim of this experiment was to examine the regulation of p38 mitogen-activated protein (MAP) kinase by platelet-derived growth factor (PDGF)-BB and its biological effects on rat cultured vascular smooth muscle cells (VSMCs). VSMCs were obtained from aortae of male Wistar rats by the media explant technique. After being stimulated by PDGF-BB with or without the p38 MAP kinase-specific inhibitor, SB-203580, the cells were solubilized, and the levels of phosphorylated p38 MAP kinase were examined by immunoblot analysis. The amounts of DNA synthesis and content were measured by using [3H]-thymidine and Hoechst-33258 dye, respectively. The detection of apoptotic cells was evaluated by the TUNEL method. PDGF-BB could phosphorylate p38 MAP kinase dose-dependently, and the phosphorylation was specifically inhibited by SB-203580 in a dose-dependent manner. However, PDGF-BB did not affect the protein level of p38 MAP kinase. Both [3H]-thymidine incorporation and total cellular DNA content were increased by PDGF-BB, and these elevations were prevented by SB-203580. In contrast, PDGF-BB-stimulated VSMCs did not show apoptotic change in spite of the presence or absence of SB-203580. These results established that PDGF-BB activated p38 MAP kinase and subsequently regulated cell growth in VSMCs, providing a molecular mechanism by which p38 MAP kinase can cause the development of cardiovascular diseases, including atherosclerosis.

Animals↗
PubMed2001

Legionnaires' disease associated with habitual drinking of hot spring water.

A 57-year-old man presented with pneumonia, respiratory distress, and myelodysplastic syndrome. A diagnosis of Legionnaires' disease due to Legionella pneumophila (L. pneumophila) was established. The patient had long been drinking tap water via a conduit from a hot spring resource, from which L. pneumophila was also isolated. Both the patient's strain and the water strain of L. pneumophila were identified as serogroup 1, and the genetic relatedness between the two strains as seen by pulsed-field gel electrophoresis was 87%. The patient was successfully treated with erythromycin, fluoroquinolone, and rifampicin. This case raises an important issue on public health represented by legionellosis in Japan.

Drinking Behavior↗
PubMed2001

Genotype Arg/Arg, but not Trp/Arg, of the Trp64Arg polymorphism of the beta(3)-adrenergic receptor is associated with type 2 diabetes and obesity in a large Japanese sample.

OBJECTIVE: Despite a large number of studies, no association of the Trp64Arg polymorphism of the beta(3)-adrenergic receptor gene with obesity and type 2 diabetes has yet to be clearly elucidated. We examined the associations in a large population-based sample. RESEARCH DESIGN AND METHODS: A total of 1,685 subjects (935 women and 750 men, aged 58.7 +/- 12.4 years) from a cohort population (n = 3,706) of the Funagata Diabetes Study were divided into three groups according to genotypes: Trp/Trp (n = 1,155), Trp/Arg (n = 486), and Arg/Arg (n = 44). Glucose tolerance was diagnosed according to the 1985 World Health Organization criteria. Subjects who had a BMI > or =30 kg/m(2) were considered obese. Associations with the traits related to obesity, diabetes, hypertension, and dyslipidemia were also examined. The chi(2) test and analysis of variance were used for the association studies and to assess the differences in the traits' values, respectively. RESULTS: More subjects with genotype Arg/Arg were obese and had diabetes (13.6% for each) than those with genotype Trp/Trp (3.29%, P < 0.001; and 4.16%, P = 0.007, respectively) or genotype Trp/Arg (2.06%, P < 0.001; and 5.97%, P = 0.051, respectively). No significant differences in the frequencies of occurrence of these conditions were observed between genotypes Trp/Arg and Trp/Trp. Traits related to obesity, such as percent body fat (28.82 +/- 7.95 vs. 25.93 +/- 7.21, P = 0.038) and BMI (25.07 +/- 3.84 vs. 23.63 +/- 3.18, P = 0.018), were higher in the genotype Arg/Arg than in the genotype Trp/Trp groups. CONCLUSIONS: Genotype Arg/Arg, but not Trp/Arg, of the beta(3)-adrenergic receptor was associated with both obesity and type 2 diabetes in a large Japanese sample.

Aged↗
PubMed2001

[Self-monitoring of blood glucose].

As the point of care testing(POCT), devices for self-monitoring blood glucose(SMBG) are most common. The problems in SMBG can be found in the popularity of SMBG itself. The reasons for the problems are three. First is the innovation of technology. As each maker has developed devices based on their own intention, device to device difference is too large, so that the standardization is needed. The second reason is the immediate measurement which, done independently of laboratory technicians, is insufficient in the quality control. The third reason is that although the health insurance covers the cost of SMBG, medical institutions buy devices and give them to patients who have limited right to choose for themselves. It is expected that specialists in laboratory medicine should be positively concerned with the standardization, introduction, and quality control of SMBG devices.

Blood Glucose Self-Monitoring↗