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Biomedical subjects

T Aoki

Publications and source records attributed to T Aoki.

At least 577 records · Page 32Linked to original sources

[Dobutamine stress causes left ventricular outflow tract obstruction].

Hypotension during dobutamine stress echocardiography is caused by ischemia as well as non-ischemic causes. Whether sigmoid interventricular septum seen in the aged can cause hypotension during dobutamine stress echocardiography was investigated in eight men and four women with sigmoid interventricular septum (aged 53 to 76 years, mean 67 +/- 7 years). At peak dobutamine dose, seven patients (group H) showed a hypotensive response (defined as 5 mmHg or greater decrease in systolic blood pressure from the peak systolic blood pressure; mean = - 17 +/- 13 mmHg), while five subjects (group N) did not. No subject showed regional wall motion abnormalities. Before dobutamine infusion, group H had smaller left ventricular end-systolic dimension (26 +/- 3 vs 30 +/- 3 mm) than group N, but no difference was found in left ventricular end-diastolic dimension (44 +/- 3 vs 47 +/- 4 mm), percentage fractional shortening (40 +/- 6% vs 34 +/- 7%), diastolic aorto-septal angle (82 +/- 10 vs 95 +/- 11 degrees), systolic aorto-septal angle (94 +/- 10 vs 101 +/- 11 degrees), peak left ventricular outflow velocity (1.3 +/- 0.2 vs 1.2 +/- 0.3 m/sec) or peak left ventricular outflow pressure gradient (7 +/- 2 vs 6 +/- 3 mmHg). Group H had a lower peak dobutamine dose than group N (33 +/- 8 vs 40 +/- 7 micrograms/kg/min), but under the peak dose of dobutamine infusion group H showed smaller left ventricular end-systolic dimension (20 +/- 3 vs 26 +/- 4 mm), systolic mitral annulus diameter (19 +/- 3 vs 23 +/- 2 mm), diastolic aorto-septal angle (72 +/- 16 vs 92 +/- 6 degrees), and systolic aorto-septal angle (84 +/- 12 vs 100 +/- 6 degrees), and higher heart rate (114 +/- 10 vs 79 +/- 16 bpm), percentage fractional shortening (53 +/- 8% vs 43 +/- 7%), peak left ventricular outflow velocity (3.2 +/- 0.8 vs 1.7 +/- 0.3 m/sec), and peak left ventricular outflow pressure gradient (43 +/- 23 vs 12 +/- 5 mmHg). In addition, systolic anterior motion of the mitral valve with septal contact developed in 86% of group H and 0% of group N. Thus, about half of the patients with sigmoid interventricular septum show hyperresponse to dobutamine and develop dynamic left ventricular outflow tract obstruction as well as systemic arterial hypotension even without regional left ventricular wall motion abnormalities.

Aged↗

Isolation of a novel mouse gene MA-3 that is induced upon programmed cell death.

Typical programmed cell death requires de novo macromolecular synthesis and shares common morphological changes referred to as apoptosis. To elucidate the molecular mechanism of apoptosis, we isolated cDNA clones that are induced in various types of apoptosis by the differential display method. Among such clones, the MA-3 mRNA was induced in all apoptosis-inducible cell lines tested so far, including thymocytes, T cells, B cells and pheochromocytoma. The nucleotide sequence of the MA-3 cDNA predicted an amino acid (aa) sequence of 469 aa, which did not reveal significant similarity to any known proteins and functional aa motifs in databases. The MA-3 mRNA was strongly expressed in the thymus although small amounts of the MA-3 mRNA were ubiquitously expressed in mouse adult tissues. The MA-3 gene was highly conserved during evolution and cross-hybridization bands were found not only in vertebrates but also in Drosophila melanogaster.

Amino Acid Sequence↗

A novel RNA splicing mutation in Japanese patients with Wilson disease.

Deletion/insertion mutation of Wilson disease (WD) gene in 16 Japanese patients with Wilson disease was studied. A truncated size in a region of exon 4 to 6 was found by reverse transcription-polymerase chain reaction (RT-PCR) covering entire 21 exons except exon 1 for liver cDNA of one patient with a late onset neurologic type. Sequence analysis of the cDNA revealed that this truncation was occurred by skipping of exon 5, though any mutation in exon 5 of genomic DNA was failed to detect. T to G transversion in 5 bp upstream from a junction of intron 4 and exon 5 was found in genomic DNA of the patient. Further, results obtained by RT-PCR and the sequence analysis in intron 4 indicate that the mutation of the patient is homozygous. Since same mutation in one allele of another patient out of 15 patients was found, allele frequency of the splicing mutation in Japanese patients is 9.4%. These results suggest that the point mutation in intron 4 of WD gene causes the skipping of exon 5 and the splicing mutation affects the phenotype of Wilson disease.

Adult↗

Cupric ion blocks NF kappa B activation through inhibiting the signal-induced phosphorylation of I kappa B alpha.

A transcription factor NF kappa B, which regulates expression of various cellular genes involved in immune responses and viral genes including HIV, is sequestered in the cytoplasm as a complex with an inhibitory protein I kappa B. Various extracellular signals induce phosphorylation and rapid degradation of I kappa B alpha to release NF kappa B. Cu2+ was found to inhibit the activation of NF kappa B induced by TNF-alpha, TPA, or H2O2. Deoxycholate treatment of the cytoplasmic extract prepared from cells stimulated by TNF-alpha in the presence of Cu2+ resulted in the release of NF kappa B from I kappa B alpha, indicating that Cu2+ interferes with the dissociation of the NF kappa B-I kappa B complex. Neither phosphorylation nor degradation of I kappa B alpha was observed upon TNF-alpha stimulation in the presence of Cu2+. These results indicate that Cu2+ inhibits the release of NF kappa B by blockade of a signal leading to the phosphorylation of I kappa B alpha.

Animals↗

Novel zinc chelators with dual activity in the inhibition of the kappa B site-binding proteins HIV-EP1 and NF-kappa B.

Both HIV-EP1 (also called PRDII-BF1 or MBP-1), a zinc finger protein, and NF-kappa B, a Rel family protein, bind to kappa B site present in the enhancer of multiple cellular and viral genes involved in immune function and inflammatory response including HIV-1 LTR and human interferon beta gene. When cells are exposed to extracellular stimuli such as virus or phorbol ester, the activity of both HIV-EP1 and NF-kappa B is induced. Thus, kappa B site-directed transcription could be regulated by two distinct proteins in a cooperative way. Novel heterocyclic compounds comprising (dimethylamino)pyridine and histidine units, i.e., 1-4, have been designed and synthesized, aiming at inhibition of these kappa B site-binding proteins to discriminate their functions. These compounds exhibited remarkable zinc-binding capability as revealed by NMR study. Compounds 1 and 2 showed a marked inhibitory effect on the DNA binding activity of HIV-EP1 by removing zinc without interfering with the DNA binding activity of NF-kappa B. Since it has been demonstrated that zinc somehow influences the DNA binding of NF-kappa B, the effect of these heterocyclic compounds and their zinc complexes on NF-kappa B was examined. Zinc complexes of 3 and 4 exhibited the inhibitory effect on the DNA binding of NF-kappa B and/or homodimeric complexes of p50 and p65 subunits of NF-kappa B without affecting HIV-EP1. Thus, it became possible to inhibit either one of the two kappa B site-binding proteins without inhibiting the other.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗

Mobilization of gastric histamine during repeated administration of a proton potassium adenosine triphosphatase inhibitor in intact and antrectomized rats.

Intact and antrectomized female rats were treated with the potent proton pump inhibitor, E3810 (daily 40 mg/kg weight, s.c.) for 4 weeks. Plasma gastrin concentration and urinary excretion of N-terminal big gastrin increased until day 14 and persisted at a high level in intact rats treated with E3810, but did not increase in antrectomized rats. Urinary excretion of histamine increased progressively and reached 7 times the control value following 4 weeks of treatment with E3810 in intact rats, but not in antrectomized rats. At the termination of the treatment, the endocrine cell density in the oxyntic mucosa of intact rats had increased by 85% with increased histamine content and elevated histidine decarboxylase activity, while antrectomized rats showed a low histamine level and low histidine decarboxylase activity. Administration of gastrin-17 I (10 micrograms/kg weight, sc) itself caused a significant increase in urinary excretion of histamine, which was inhibited by the specific gastrin receptor antagonist, L-365,260. These results suggests that the massive urinary excretion of histamine caused by the treatment with E3810 reflects gastrin-induced mobilization of gastric histamine and that neither E3810 itself nor E3810-induced luminal pH elevation has direct effects on mobilization of oxyntic mucosal histamine.

2-Pyridinylmethylsulfinylbenzimidazoles↗

Discordant expression and variable numbers of neighboring GGA- and GAA-rich triplet repeats in the 3' untranslated regions of two groups of messenger RNAs encoded by the rat polymeric immunoglobulin receptor gene.

An unusual S1-nuclease sensitive microsatellite (STMS) has been found in the single copy, rat polymeric immunoglobulin receptor gene (PIGR) terminal exon. In Fisher rats, elements within or beyond the STMS are expressed variably in the 3' untranslated regions (3'UTRs) of two 'Groups' of PIGR-encoded hepatic mRNAs (pIg-R) during liver regeneration. STMS elements include neighboring constant regions (a 60-bp d[GA]-rich tract with a chi-like octamer, followed by 15 tandem d[GGA] repeats) that merge directly with 36 or 39 tandem d[GAA] repeats (Fisher or Wistar strains, respectively) interrupted by d[AA] between their 5th-6th repeat units. The Wistar STMS is flanked upstream by two regions of nearly contiguous d[CA] or d[CT] repeats in the 3' end of intron 8; and downstream, by a 283 bp 'unit' containing several inversions at its 5' end, and two polyadenylation signals at its 3' end. The 283 nt unit is expressed in Group 1 pIg-R mRNAs; but it is absent in the Group 2 family so that their GAA repeats merge with their poly A tails. In contrast to genomic sequence, GGA triplet repeats are amplified (n > or = 24-26), whereas GAA triplet repeats are truncated variably (n < or = 9-37) and expressed uninterruptedly in both mRNA Groups. These results suggest that 3' end processing of the rat PIGR gene may involve misalignment, slippage and premature termination of RNA polymerase II. The function of this unusual processing and possible roles of chi-like octamers in quiescent or extrahepatic tissues are discussed.

Animals↗

Temperature acclimation induces light meromyosin isoforms with different primary structures in carp fast skeletal muscle.

Carp acclimated to 10 degrees C gave 69k, 66k, and 62kDa light meromyosin (LMM) fragments in SDS-PAGE, while fish acclimated to 30 degrees C gave 74k, 69k, 66k, and 62kDa fragments. The microsequence analysis revealed that the 69k and 66kDa components from the 10 degrees C-acclimated carp contained an N-terminal amino acid sequence different from that of 62kDa. The four fragments from the 30 degrees C-acclimated carp showed the same sequence as that of the 69k and 66kDa components from the 10 degrees C-acclimated carp, except that the 2nd amino acid, Ala, of the 10 degrees C-acclimated LMM was replaced by Thr. DNA fragments encoding an N-terminal region of LMM were amplified by PCR or reverse transcriptase-PCR, demonstrating that the two acclimated groups further contained several amino acids substituted.

Acclimatization↗

Stage-specific isoforms of complex II (succinate-ubiquinone oxidoreductase) in mitochondria from the parasitic nematode, Ascaris suum.

Complex II from mitochondria of the adult parasitic nematode, Ascaris suum, exhibits high fumarate reductase activity and plays a key role in the anaerobic electron transport observed in these organelles. In contrast, mitochondria isolated from free living second stage larvae (L2) of A. suum show much lower fumarate reductase activity than those from adults, whereas succinate dehydrogenase activities of mitochondria in both stages are comparable. In the present study, biochemical and antigenic properties of the partially purified enzymes from both larval and adult mitochondria were compared. Larval complex II eluted from the DEAE-Cellulofine column chromatography at a lower salt concentration than adult enzyme, whereas the apparent molecular size of both enzyme complexes estimated by gel permeation column chromatography was the same. The fumarate reductase activity of larval complex II was less than 3% of that of adult enzyme, and the Km values for substrates were significantly different between the two complexes. The flavoprotein subunit of larval complex II could be distinguished from that of adult complex II by two-dimensional gel electrophoresis and peptide mapping. The antibody against the smallest subunit (small subunit of cytochrome b558) of the adult enzyme did not cross-react with that of the larval enzyme. These results suggest that larval complex II differs from adult enzyme and is more similar to aerobic mammalian enzymes with low fumarate reductase activity. This is the first direct indication of the two different stage-specific forms of mitochondrial complex II.

Animals↗

Gene rearrangement studies on lymphoma of the lung: report of a case.

We describe herein how true lymphoma of the lung was differentiated from pseudolymphoma in a 45-year-old woman presenting with pulmonary infiltrates. Although segmental resection revealed typical histologic findings of pseudolymphoma of the lung and immunohistochemical studies did not demonstrate a monoclonal proliferation, Southern blot analysis of the frozen tissue revealed rearrangements in the heavy and light chains of the immunoglobulin gene, with no T-cell receptor gene rearrangement suggestive of a lymphoproliferative disorder. These findings indicate that the identification of gene rearrangement may be utilized to distinguish between true lymphoma and pseudolymphoma.

Blotting, Southern↗

An index to predict outcome of surgery for reflux esophagitis based on the AFP classification.

Fifteen patients with reflux esophagitis were treated surgically from July 1990 to April 1994. We evaluated these patients using the anatomic-functional-pathologic (AFP) classification both prior to and following the operation. An objective index for surgical outcome was devised. By using the grades Ai, Fj, and Pk, the i2 + j2 + k2 score was determined. The scores ranged from 3 to 22 (mean 9.1 +/- 5.4) prior to the operation. Postoperatively, 12 (80%) of 15 patients showed a complete recovery with a numerical score of 0, and their symptoms also disappeared. The scores of these 12 patients prior to the operation ranged between 3 and 11. However, the other 3 patients did not exhibit a complete recovery. Their scores prior to the operation ranged between 17 and 22, and the symptoms in 2 of these 3 patients persisted following the operation. These results suggest that surgical treatment for reflux esophagitis can be expected to be successful if the preoperative AFP score is less than 11.

Adult↗

Analysis of zinc and other elements in rat pancreas, with studies in acute pancreatitis.

Determination of the concentration of certain elements makes it possible to investigate the physiology of the pancreas. We used X-ray fluorescence to determine the concentrations of zinc and other elements in the pancreas of normal (control) rats and those with cerulein-induced pancreatitis. Ten elements (Zn, Ni, Fe, P, Ca, Cl, S, K, Ti, and Mn) were detected in controls. In the early stage of acute pancreatitis, the pancreatic concentrations of Zn, Ni, Fe, and P were significantly decreased (P < 0.05) and those of Ca and Cl were significantly increased (P < 0.05), compared with control levels. However, levels of S, K, and Ti did not differ significantly from the control values. Mn was detected in only some samples. The serum levels of Zn and Fe were significantly elevated (P < 0.05) in acute pancreatitis. These observations indicate that Zn and these other nine elements could play an important role in acute pancreatitis.

Acute Disease↗

Immunoelectron microscopic analysis of chondroitin sulfates during calcification in the rat growth plate cartilage.

The proximal growth plate cartilage of rat tibia was fixed in the presence of ruthenium hexamine trichloride (RHT) in order to preserve proteoglycans in the tissue. Quantitative changes of chondroitin sulfates during endochondral calcification were investigated by immunoelectron microscopy using mouse monoclonal antibodies 1-B-5, 2-B-6, and 3-B-3, which recognize unsulfated, 4-sulfated, and 6-sulfated chondroitin sulfates, respectively. The content of chondroitin-4-sulfate in the cartilage matrix increased from the proliferative zone to the calcifying zone, while that of unsulfated chondroitin sulfate decreased. Chondroitin-6-sulfate remained constant from the proliferative zone to the upper hypertrophic zone, then decreased in the calcifying zone. The immunoreaction to each antibody increased conspicuously in the cartilagenous core of metaphysial bone trabeculae. The changes of sulfation in chondroitin sulfate chains of proteoglycans may play an important role in inducing and/or promoting calcification in growth plate cartilage.

Animals↗

Temperature-modulated platelet and lymphocyte interactions with poly(N-isopropylacrylamide)-grafted surfaces.

Temperature-responsive semitelechelic poly(N-isopropylacrylamide) (PIPAAm) bearing a carboxyl end group has been chemically immobilized on aminated polystyrene particle surfaces via condensation reaction. PIPAAm-grafted particles were uniformly suspended in aqueous media at lower temperatures. With increasing temperature, PIPAAm-grafted particles aggregated and precipitated. Such reversible changes in particle colloidal behaviour was correlated to temperature-modulated hydrophilic/hydrophobic changes of particle surfaces modified by PIPAAm hydration/dehydration with temperature changes. Interactions between platelets and PIPAAm-grafted surfaces were studied by monitoring cytoplasmic free Ca2+ concentration ([Ca2+]i) changes in platelets using intracellularly-trapped Ca2+ indicator dye, Fura 2, at various temperatures. Although changes in [Ca2+]i in platelets in contact with PIPAAm-grafted particles were not observed below the critical temperature of PIPAAm, significant changes in [Ca2+]i in platelets were induced by contact with particles above this critical temperature. Furthermore, temperature-modulated cell adsorption/desorption control by PIPAAm-grafted particles was investigated using a particle aggregation assay in the presence of lymphocytes. Below the critical temperature of PIPAAm, mixed suspensions were completely homogeneous due to minimal interaction between lymphocytes and hydrated particles. In contrast, aggregated precipitates were observed by increasing the suspension temperature above the critical temperature of PIPAAm resulting from strong hydrophobic interactions between particles with lymphocytes. These precipitates are reversibly resuspended in cold buffer. The feasibility of cell activation/inactivation or cell attachment/detachment control by temperature-modulated surface changes is attractive for suspension cell culture and drug delivery at targeted sites in vivo.

Acrylic Resins↗