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Biomedical subjects

K Akimoto

Publications and source records attributed to K Akimoto.

At least 91 records · Page 5Linked to original sources
PubMed1995

Phosphatidylinositol 3-kinase is involved in TRE-dependent gene expression in response to arginine vasopressin.

We identified arginine vasopressin (AVP) as a potent activator of TPA-response element (TRE)-dependent gene expression in rat 3Y1 fibroblasts. In order to examine the involvement of phosphatidylinositol 3-kinase (PI3-kinase) in TRE-mediated gene expression, we examined the effect of the overexpression of PI3-kinase mutant. The overexpression of p110 alpha, the catalytic subunit of PI3-kinase, enhances TRE-reporter expression in response to AVP. On the other hand, the overexpression of the p110-EcoS mutant, which contains the binding site for the regulatory p85 subunit but lacks the catalytic domain, results in decreased TRE reporter expression in response to AVP. These results suggest that PI3-kinase is involved in TRE-dependent gene expression in response to AVP.

Animals↗
PubMed1995

Preparation of 13C-labeled polyunsaturated fatty acids by an arachidonic acid-producing fungus Mortierella alpina 1S-4.

Three types of 13C-labeled polyunsaturated fatty acids (PUFAs) were produced in mycelia of an arachidonic acid-producing fungus, Mortierella alpina 1S-4, when grown with 13C-labeled glucose or fatty acid methyl esters. We analyzed them by negative-ion fastatom bombardment mass spectrometry. (i) PUFA in mycelia grown with [1-(13)C]glucose or [2-(13)C]glucose was a mixture of molecules containing zero to six labeled carbons. The content of 13C in the total carbon atoms of PUFA, such as arachidonic (20:4 omega 6), dihomo-gamma-linolenic (20:3 omega 6), gamma-linolenic (18:3 omega 6), and linoleic (18:2 omega 6) acids, in the mycelia grown with [1-(13)C]-glucose or [2-(13)C]glucose was about 11 or 15%, respectively. More than 80% of these PUFA had more than one 13C atom. (ii) When the fungus was grown with [U-13C]glucose, the content of PUFA molecules, all carbons of which were 13C-labeled, was about 20%. The percentage of 13C in PUFA from [U-13C]glucose was 78-83%, over 98% of which had more than one 13C atom. The 13C atoms in the labeled fatty acids formed from 13C-labeled glucose were thought to be distributed at random by a two carbon-unit. (iii) The 13C atom of PUFA in mycelia grown with 1-(13)C-labeled fatty acid methyl esters was highly localized. More than half of the 20:4 omega 6 molecules had only one 13C atom at C-3, C-5, or C-7 when the fungus was grown with methyl [1-13c]stearate, methyl [1-(13)C]palmitate, or methyl [1-(13)C]-myristate, respectively.

Arachidonic Acid↗
PubMed1995

Structure-activity relationship of alpha-galactosylceramides against B16-bearing mice.

Agelasphin-9b, (2S,3S,4R)-1-O-(alpha-D-galactopyranosyl)-16-methyl-2- [N-((R)-2- hydroxytetracosanoyl)-amino]- 1,3,4-heptadecanetriol, is a potent antitumor agent isolated from the marine sponge Agelas mauritianus. Various analogues of agelasphin-9b (a lead compound) were synthesized, and the relationship between their structures and biological activities was examined using several assay systems. From the results, KRN7000, (2S,3S,4R)-1-O-(alpha-D- galactopyranosyl)-2-(N-hexacosanoylamino)-1,3,4-octadecanetriol , was selected as a candidate for clinical application.

Animals↗
PubMed1995

Rapid determination of dabsylated hydroxyproline from cultured cells by reversed-phase high-performance liquid chromatography.

A high-performance liquid chromatographic method was modified for the determination of hydroxyproline in cultured cells derived from rat liver. First, the primary amino group in the cell hydrolysate was blocked with o-phthalaldehyde, then the secondary amino group was derivatized with 4-dimethylaminoazobenzene-4'-sulfonyl chloride (dabsyl chloride). The dabsylated sample was treated with ethyl acetate to obtain a simple chromatographic elution profile of the cell hydrolysate. Dabsylhydroxyproline and proline were separated from other compounds by high-performance liquid chromatography in the gradient elution mode, and eluted at 4.71 and 8.00 min, respectively. The method was applied to the determination of hydroxyproline contained in cultured cells, the result being 25.4 +/- 3.6 pmol/microgram.

Acetates↗
PubMed1995

Secretion of TNF-alpha from macrophages following induction with a lignin derivative.

Macrophages derived from rat bone marrow were treated with macrophage colony stimulating factor (M-CSF) to obtain a sufficient number of cells for the tumor necrosis factor (TNF-alpha) assay. The present study has been designed to investigate whether the production of TNF-alpha, which induces multinucleated giant cell formation, is regulated by polyanions such as lignin derivatives. ELISA for TNF-alpha showed that the polyanion induced TNF-alpha production by macrophages. The secretion of TNF-alpha from the cells reached a maximum at 3-6 h, and then showed a slight decline. Northern blotting of TNF-alpha mRNA showed that the amount of TNF-alpha reached a maximum within 1 h of macrophage culture in the presence of a lignin derivative. On the other hand, TNF-alpha mRNA was undetectable in the control cells. It was concluded that stimuli such as that provided by lignin derivatives increases the amount of TNF-alpha mRNA, which is then followed by translation of TNF-alpha.

Animals↗
PubMed1995

Mechanism of balloon angioplasty in children with arterial stenosis assessed by intravascular ultrasound and angiography.

Fifteen patients were examined before and immediately after balloon angioplasty with a 4.3F, 30 MHz rotational tip intravascular ultrasound system. In 12 (80%) patients, 13 procedures could be analyzed because of sufficient image quality. The lesions for intravascular ultrasound (IVUS) study consisted of pulmonary arterial stenosis in 4 patients, Blalock-Taussig shunt stenosis in 3, coarctation of the aorta in 2, subclavian artery stenosis in 1, renal artery stenosis in 1, and ductus arteriosus in 1. Three distinctive morphologic types were identified: Group I had arterial stretching (3 patients); group IIa had superficial tearing (3); group IIb had deep intimal-medial tearing (5); group III had dissection (2). In the narrowest site, minimal and maximal luminal diameters, luminal area before and after balloon angioplasty were 3.5 +/- 1.8 mm vs 4.5 +/- 2.5 mm, 4.1 +/- 2.1 mm vs 5.4 +/- 3.5 mm, and 49.8 +/- 30.2 mm vs 88.3 +/- 45.2 mm2, respectively. The recoil value of group IIb with appropriate balloon angioplasty was approximately 0.3. IVUS may be an useful modality for evaluating the morphologic mechanism of dilatation after balloon angioplasty.

Adult↗
PubMed1995

Left aortic arch with right descending aorta and right ligamentum arteriosum associated with d-TGA and large VSD: surgical treatment of a rare form of vascular ring.

A 1-month-old boy with respiratory distress underwent pulmonary artery banding after diagnosis of d-loop transposition of the great arteries and ventricular septal defect. Respiratory distress recurred after surgery. Angiography, esophagography, and magnetic resonance imaging showed left aortic arch, retroesophageal aorta, and right descending aorta. Surgery at 9 months of age showed a right-sided ligamentum arteriosum. Division of the ligamentum relieved the constriction of the esophagus and trachea caused by this rare form of vascular ring.

Aorta, Thoracic↗
PubMed1995

Corticosteroid therapy for ventricular tachycardia in children with silent lymphocytic myocarditis.

OBJECTIVE: The objective of our study was to describe the efficacy of corticosteroids for ventricular tachycardia in four children with structurally normal hearts in whom endomyocardial biopsy revealed histologic changes of lymphocytic myocarditis. PATIENTS: The four patients had unexplained ventricular tachycardia. Three dysrhythmias were sustained, and one was inducible by exercise. Patient ages ranged from 4 months to 12 years. Three of the four patients had no symptoms. In two of them, ventricular tachycardia was identified by mass screening for heart disease. Two patients received oral steroids and two received pulse steroid therapy. RESULTS: In all four patients, significant underlying diseases were not found by noninvasive evaluation. Right ventricular endomyocardial biopsy revealed abnormal histologic findings of chronic lymphocytic myocarditis in all patients. Steroid therapy was effective in all four patients, two of whom received methylprednisolone pulse therapy. CONCLUSIONS: We conclude that unexplained ventricular tachycardia may be the only manifestation of clinically silent myocarditis. Steroid therapy should therefore be considered if conventional antiarrhythmic medication is not effective and histologic findings confirm the presence of lymphocytic myocarditis.

Adolescent↗
PubMed1995

Identification of a novel dual angiotensin II/vasopressin receptor on the basis of molecular recognition theory.

The molecular recognition theory suggests that binding sites of interacting proteins, for example, peptide hormone and its receptor binding site, were originally encoded by and evolved from complementary strands of genomic DNA. To test this theory, we screened a rat kidney complementary DNA library twice: first with the angiotensin II (AII) followed by the vasopressin (AVP) antisense oligonucleotide probe, expecting to isolate cDNA clones of the respective receptors. Surprisingly, the identical cDNA clone was isolated twice independently. Structural analysis revealed a single receptor polypeptide with seven predicted transmembrane regions, distinct AII and AVP putative binding domains, a Gs protein-activation motif, and an internalization recognition sequence. Functional analysis revealed specific binding to both AII and AVP as well as AII- and AVP-induced coupling to the adenylate cyclase second messenger system. Site-directed mutagenesis of the predicted AII binding domain obliterates AII binding but preserves AVP binding. This corroborates the dual nature of the receptor and provides direct molecular genetic evidence for the molecular recognition theory.

Adenylyl Cyclases↗
PubMed1995

The effect of lansoprazole treatment on the healing and relapse of peptic ulcer and serum levels of IgG anti-Helicobacter pylori antibody.

In the present study, the effects of short-term treatment with lansoprazole on healing and recurrence of peptic ulcer were investigated. Complete healing (change to the S2 stage) after 3 or 4 weeks of treatment with lansoprazole was observed in 9.9% of gastric ulcers and 38.3% of duodenal ulcers. Complete healing was observed after 3 or 4 weeks of treatment with lansoprazole in gastric ulcers and was significantly related to the serum titer of IgG anti-Helicobacter pylori antibodies. This was not the case in duodenal ulcers. Complete healing after 6 or 8 weeks of treatment with lansoprazole was not dependent on serum levels of IgG anti-H. pylori antibodies. Short-term treatment by lansoprazole did not affect serum levels of IgG anti-H. pylori antibodies immediately after the end of lansoprazole treatment, but significantly reduced serum levels of IgG anti-H. pylori antibodies were found 9 months after treatment.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Effect of tumor cell conditioned media on secretion of TNF-alpha by macrophages.

Conditioned medium obtained from rat liver (M cells) induced a greater than 3 fold increase in the proliferation of rat bone marrow macrophages. Non-specific esterase staining of the proliferated cells gave a positive result. The conditioned media obtained from 8 other established cell lines and 2 primary human cell cultures were also examined for their effects on cultured macrophages. All of the conditioned media tested increased macrophage proliferation. In addition, the conditioned media were examined to determine whether they induced TNF-alpha production in macrophages. TNF-alpha was not detected in the culture medium of the macrophages in the absence of conditioned medium derived from other cell cultures, but TNF-alpha production could be induced by the addition of these conditioned media. Conditioned media obtained from the cells of different species or tumor cell lines were more effective in inducing TNF-alpha production than those obtained from rat cell lines or normal tissue cell lines.

Animals↗
PubMed1995

Antihypertensive effect of sesamin. I. Protection against deoxycorticosterone acetate-salt-induced hypertension and cardiovascular hypertrophy.

We investigated the antihypertensive effect of sesamin, a lignan from sesame oil, using deoxycorticosterone acetate (DOCA)-salt hypertensive rats. The animals were unilaterally nephrectomized, and then separated into a sham-operated group (sham group) and a DOCA-salt-treated group. The latter was further separated into a normal diet group (control group) and a sesamin-containing diet group (sesamin group). The systolic blood pressure of control group progressively increased in comparison with that of sham group. This DOCA-salt-induced hypertension was markedly suppressed by feeding a sesamin-containing diet. Systolic blood pressure after 5 weeks was 130.6 +/- 1.9 mmHg in the sham group, 198.1 +/- 7.3 mmHg in the control group and 152.5 +/- 8.4 mmHg in the sesamin group, respectively. The treatment with DOCA and salt for 5 weeks significantly increased the weight of the left ventricle plus the septum. However, this increase was significantly suppressed in the sesamin group. When the degree of vascular hypertrophy of the aorta and superior mesenteric artery was histochemically evaluated, there were significant increases in wall thickness, wall area and the wall-to-lumen ratio in the control group, compared with the sham. Sesamin feeding ameliorated the development of DOCA-salt-induced vascular hypertrophy in both the aorta and mesenteric artery. These findings strongly suggest that sesamin is useful as a prophylactic treatment in the development of hypertension and cardiovascular hypertrophy.

Animals↗