Tear injuries and upper endoscopy.
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Aged↗
Biomedical subjects
H Miyoshi
Publications and source records attributed to H Miyoshi.
Cloning and gene mapping of the mouse homologue of the CBFA2T1 gene associated with human acute myeloid leukemia.
The human CBFA2T1 (also known as MTG8) gene, on chromosome 8, has been identified through its involvement in the t(8;21) chromosomal translocation, frequently found in acute myeloid leukemia. We report here the isolation and characterization of the mouse homologue of the CBFA2T1 gene, Cbfa2t1h. Nucleotide sequence analysis of Cbfa2t1h cDNA clones revealed an open reading frame encoding a protein of 577 amino acids with an extremely high degree of amino acid identity (99.3%) to the human protein. The nucleotide sequence is also highly conserved between mouse and human in the 5'- and 3'-untranslated regions (87.0, 92.0, and 93.7% identities for 5'-untranslated, coding, 3'-untranslated regions, respectively). The 3'-untranslated region of Cbfa2t1h contains a (CA)n dinucleotide repeat, and the polymerase chain reaction amplification of the (CA)n repeat region revealed fragment length polymorphism among mouse strains. Using this polymorphism, we have mapped Cbfa2t1h to mouse chromosome 4 close to the centromere using SMXA recombinant inbred strains and 106 intersubspecific backcross progenies of the (DBA/2 x Mae) x Mae cross. The chromosomal location was also confirmed by fluorescence in situ hybridization.
Acute Disease↗
Alternative splicing and genomic structure of the AML1 gene involved in acute myeloid leukemia.
We previously isolated the AML1 gene, which is rearranged by the t(8;21) translocation in acute myeloid leukemia. The AML1 gene is highly homologous to the Drosophila segmentation gene runt and the mouse transcription factor PEBP2 alpha subunit gene. This region of homology, called the Runt domain, is responsible for DNA-binding and protein--protein interaction. In this study, we isolated and characterized various forms of AML1 cDNAs which reflect a complex pattern of mRNA species. Analysis of these cDNAs has led to the identification of two distinct AML1 proteins, designated AML1b (453 amino acids) and AML1c (480 amino acids), which differ markedly from the previously reported AML1a (250 amino acids) with regard to their C-terminal regions, although all three contain the Runt domain. The large C-terminal region common to AML1b and AML1c is suggested to be a transcriptional activation domain. AML1c differs from AML1b by only 32 amino acids in the N-terminal. Characterization of the genomic structure revealed that the AML1 gene consists of nine exons and spans > 150 kb of genomic DNA. Northern blot analysis demonstrated the presence of six major transcripts, encoding AML1b or AML1c, which can all be explained by the existence of two promoters, alternative splicing and differential usage of three polyadenylation sites. A minor transcript encoding AML1a which results from alternative splicing of a separate exon can be detected only by reverse transcription-polymerase chain reaction amplification. The distinct proteins encoded by the AML1 gene may have different functions, which could contribute to regulating cell growth and/or differentiation through transcriptional regulation of a specific subset of target genes.
Alternative Splicing↗
A model of antimycin A binding based on structure-activity studies of synthetic antimycin A analogues.
The structural factors of antimycin A molecule required for inhibitory action were studied using newly synthesized antimycin A derivatives with bovine heart submitochondrial particles, in order to probe the interaction between antimycin A and its binding site. In particular, we focused upon the roles of the amide bond bridge, which connects the salicylic acid and dilactone ring moieties, and the 3-formylamino group in the salicylic acid moiety. The lack of formation of an intramolecular hydrogen-bond between phenolic OH and amide carbonyl groups resulted in a remarkable loss of the activity (by four orders of magnitude), indicating that this hydrogen-bond is essential for the inhibition. This result suggested that both the phenolic OH and the carbonyl groups form a hydrogen-bond with some residues at a fixed conformation. In addition, the inhibitory potency was remarkably decreased by N-methylation of the amide bond moiety, indicating that the NH group might function in hydrogen-bond interaction with the binding site. The N-methylation of 3-formylamino group also resulted in a decrease in the activity, probably due to a loss of the rotational freedom of this functional group. Molecular orbital calculation studies with respect to the conformation of the 3-formylamino group indicated that this group takes an active conformation when the formyl carbonyl projects to the opposite side of the phenolic OH group. Based upon a series of structure-activity studies of synthetic antimycin A analogues, we propose a tentative model for antimycin A binding in its binding cavity.
Amides↗
MCI-154 activates the Ca(2+)-activated K+ channel of vascular smooth muscle cells.
The aim of this study was to examine the effects of MCI-154, a new positive inotropic agent with vasodilating properties, on the Ca2+-activated K+ channel (KCa channel) of vascular smooth muscle cells. Cultured smooth muscle cells from a porcine coronary artery were studied using the patch-clamp technique. Extracellular application of 100 microM MCI-154 activated the KCa channel in intact cell-attached patch configurations. In excised inside-out patch configurations, application of 100 microM MCI-154 to the cytosolic side activated the KCa channel directly, suggesting that the Ca2+ sensitivity of the KCa channel itself is modulated. Though extracellular application of 100 microM amrinone, a phosphodiesterase inhibitor, activated the KCa channel in the cell-attached patch configurations, application of 100 microM amrinone to the cytosolic side could not activate the KCa channel in inside-out patch configurations. These results indicate that different from amrinone, MCI-154 can modulate Ca2+ sensitivity of the KCa channel in vascular smooth muscle cells.
Amrinone↗
Transferrin is not involved in initial uptake process of iron in rat duodenal mucosa. Ultrastructural study by x-ray energy spectrometry.
The role of transferrin in iron absorption by the duodenal mucosa in rats with iron deficiency and controls was evaluated immunohistochemically. Ferric iron was administered to each rat using a metallic gastric tube. Transferrin was stained by an immunoperoxidase method and iron with Prussian blue in the same duodenal sections and observed by light microscopy. The localization of transferrin differed from that of ferric iron both in rats with iron deficiency and in controls. In iron-deficient rats, transferrin was weakly stained after iron administration but was strongly stained after saline administration. In contrast, in controls, transferrin was weakly stained after saline administration but was strongly stained after iron administration. By electron microscopy, x-ray energy spectrometric analysis of the transferrin-positive areas showed no iron peak. In iron-deficient rats, accumulation of electron-dense transferrin-negative microgranules was observed in some of the duodenal columnar epithelium. X-ray energy spectrometric analysis of this area revealed iron, indicating iron absorption. These results suggest that mucosal transferrin does not act as a shuttle protein in iron absorption via the rat duodenal columnar epithelium, and the function of this protein may be to inform the absorptive cells of the iron status of the body as observed in other organs.
Animals↗
Proton magnetic resonance spectroscopy of brain in congenital myotonic dystrophy.
Volume selective proton magnetic resonance spectroscopy of brain was performed on a 1.5 T magnet in 5 patients with congenital muscular dystrophy and compared to the results in 46 healthy children and 1 healthy adult. Peaks of N-acetyl aspartate, choline, and creatine but not lactate, were observed in both groups on proton magnetic resonance spectroscopy. Spectroscopy of controls revealed an increase with advancing age in the ratio of N-acetyl aspartate/choline and N-acetyl aspartate/creatine and a decrease in the choline/creatine ratio. In patients with congenital myotonic dystrophy, the N-acetyl aspartate/choline ratio did not increase with advancing age, but the N-acetyl aspartate/creatine ratio did. The choline/creatine ratio decreased with advancing age, which matched the results of controls. At any age older than 4 years, the N-acetyl aspartate/choline and N-acetyl aspartate/creatine ratios were lower in patients with congenital myotonic dystrophy than in controls. The choline/creatine ratio did not differ between congenital myotonic dystrophy and controls. These results suggest that in patients with congenital myotonic dystrophy N-acetyl aspartate decreases and there exists a developmental disorder of neurons in brain.
Adolescent↗
Reduced N-acetylaspartate in the brain observed on in vivo proton magnetic resonance spectroscopy in patients with mental retardation.
Volume-selective proton magnetic resonance spectroscopy (1H-MRS) of the brain was performed with a 1.5T magnet in 28 patients with unclassified mental retardation (MR) and in 25 age-matched healthy children. Peaks of N-acetylaspartate (NAA), choline (Cho), and creatine (Cr), but not of lactate, were observed in both groups on 1H-MRS. In all our subjects of this age range, 1H-MRS revealed an increase with advancing age in the ratio of NAA/Cho (P = .0031), but no developmental change in the NAA/Cr and Cho/Cr ratios. The NAA/Cho ratio was lower in patients with MR than in controls (P = .0016). The NAA/Cr ratio tended to be lower in the MR group, and the Cho/Cr ratio did not differ between patients with MR and controls. These results suggest that in patients with MR, NAA decreases and a disorder and/or dysfunction of neurons in the brain exists.
Adolescent↗
Suppressive action of lansoprazole on gastric acidity and its clinical effect in patients with gastric ulcers: comparison with famotidine.
We studied the action on acid secretion of lansoprazole compared with famotidine by 24-h intragastric pH monitoring, evaluated its clinical effects prospectively, and assessed the importance of acid inhibition in gastric ulcer patients. Twenty symptomatic patients with active gastric ulcers diagnosed by endoscopy were assigned to a lansoprazole (LAN) group (lansoprazole 30 mg q.d., n = 10) or a famotidine (FAM) group (famotidine 20 mg b.i.d., n = 10). There were no differences between the groups in pretreatment pH profiles or background factors such as age, sex, smoking, previous ulcer therapy, ulcer site, or Helicobacter pylori infection. The FAM group showed a continuous increase in intragastric pH during the night, with low pH values except for a transient increase associated with food intake during the day. However, the LAN group showed a more neutral pH throughout the day, with pH-3 holding time ratios of 99.0% for 24 h, 98.3% at night, and 99.8% during the day, compared with 68.0, 76.5, and 59.4%, respectively, in the FAM group. The healing rate was also higher in the LAN group. We conclude that inhibition of gastric acidity is important in ulcer therapy and that lansoprazole is superior to famotidine in promoting ulcer healing.
2-Pyridinylmethylsulfinylbenzimidazoles↗
Experimental examination of the Booth theory on the first-order electroviscous effect in ionic colloidal dispersions.
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Journal Article↗
Non-invasive characterization of brain tumor by in-vivo proton magnetic resonance spectroscopy.
We studied the feasibility of characterizing brain tumor tissue by localized proton magnetic resonance spectroscopy (1H-MRS). Twenty-six newly diagnosed tumors were examined by in-vivo 1H-MRS. The NAA (N-acetylaspartate)/Cho (choline) ratio of Grade 2 astrocytoma was higher than that of Grade 4. The Cho/Cr (creatine and phosphocreatine) ratio of meningioma was considerably higher than that of glioma of all grades. We have experienced only two cases of ependymoma and the Cho/Cr ratios of both were lower than that of glioma. It seems likely that 1H-MRS can be used to differentiate Grade 2 from Grade 4 in most cases of astrocytoma based on the NAA/Cho ratio, though a few cases will overlap. Meningioma can be distinguished easily from glioma, and the results of our study suggest that ependymoma shows a characteristic pattern on 1H-MRS, different from those of other brain tumors.
Aspartic Acid↗
Developmental brain changes investigated with proton magnetic resonance spectroscopy.
Volume-selective proton magnetic resonance spectroscopy (1H-MRS) of the brain was performed with a 1.5 Tesla magnet in 47 healthy children and in six healthy adults. Peaks of N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) were observed in all cases, but a lactate peak was not observed. In the right parietal region. 1H-MRS revealed increases in the rations of NAAJCho and NAA/Cr and a decrease in Cho/Cr with advancing age. The most rapid changes were noted between one and three years of age. 1H-MRS of the right frontal region also was performed in 21 cases (20 children and one adult). In the right frontal region, there was an increase in the ratio of NAA/Cho and a decrease in Cho/Cr with advancing age, while a developmental change was not observed in the ratio of NAA/Cr. The ratios of both NAA/Cho and NAA/Cr were lower in the right frontal region than in the right parietal region. These results show that developmental changes and regional variation of metabolites are observed in 1H-MRS of the brain, and need to be considered in its application.
Adolescent↗
Intestinal protein loss and bleeding assessed by fecal hemoglobin, transferrin, albumin, and alpha-1-antitrypsin levels in patients with colorectal diseases.
Four fecal proteins (hemoglobin, transferrin, albumin, and alpha 1-antitrypsin) were measured by enzyme-linked immunosorbent assay (ELISA) in patients with colorectal diseases. Levels of all 4 proteins were significantly increased in patients with colonic cancer and ulcerative colitis (UC) compared to levels in control subjects, while fecal alpha 1-antitrypsin was particularly elevated in colonic Crohn's disease (CD). That is, the fecal protein pattern of CD was distinct from those of colonic polyps, colonic cancer, and UC. To investigate whether levels of these fecal proteins reflect disease activity in UC and CD, comparative evaluation of fecal proteins in the active and inactive phases was performed. In UC, differences in the fecal concentrations of all 4 proteins were significant between the active and inactive phases of the disease. In CD, however, the difference in alpha 1-antitrypsin concentration was significant. Our results suggest that measurements of these 4 fecal proteins would be useful in the screening of colorectal diseases. In addition, these markers can also be used as indicators of disease activity in inflammatory bowel diseases.
Adult↗
[A case of intrapancreatic accessory spleen with epidermoid cyst].
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Choristoma↗
[A trial for quantification of proton MR spectroscopy: relaxation times of each metabolite and concentration using water signal as an internal standard].
We conducted quantification of proton MR spectroscopy (1H-MRS) using water signal as an internal standard. The 1H-MR spectrum was measured with and without water suppression pulses. For calculation of relaxation times, measurement conditions of the PRESS sequence were as follows: TR = 1500, 3000, 5000 ms, TE = 135,270 ms. The T1 relaxation and T2 relaxation of each metabolite were calculated by fitting to the curve of the equation of the spin echo sequence. The signal intensities of each metabolite were corrected using relaxation times and such corrected intensities were used for the quantitative calculation. The concentration of each metabolite was obtained from ratios of the corrected intensities of water and metabolites. The value of each concentration was coincident with that reported in the previous literature. We considered that this quantification using water signal as an internal standard would be very useful when the proton-weighted image does not show remarkable change.
Adult↗
[Proton MR spectroscopy of the brain in patients with congenital myotonic dystrophy].
Volume selective proton MR spectroscopy (1H-MRS) of the brain was performed on a 1.5T magnet in five patients with congenital muscular dystrophy (CMyD), 46 healthy children, and one healthy adult. Peaks of N-acetylaspartate (NAA), choline (Cho) and creatine (Cr) were observed in both patients and control groups on 1H-MRS, but lactate was not observed. 1H-MRS revealed an increase in the ratio of NAA/Cho and NAA/Cr, and a decrease in Cho/Cr ratio with age in control subjects. In patients with CMyD, the values of NAA/Cho ratio did not increase with age. The values of NAA/Cr ratio decreased with age. The values of Cho/Cr ratio decreased with age in both patient and control groups. At age more than 4 years, the values of NAA/Cho and NAA/Cr ratios were lower in patients with CMyD than in controls. The values of Cho/Cr ratio did not differ between CMyD and controls. These results suggest that in patients with CMyD, there is an NAA decrease and a developmental disorder of neurons in the brain.
Adolescent↗
Structure-function studies on the ubiquinol oxidation site of the cytochrome bo complex from Escherichia coli using p-benzoquinones and substituted phenols.
To characterize the structural features of the quinol oxidation site (the QL site) of the cytochrome bo complex, a heme-copper respiratory oxidase in Escherichia coli, we carried out structure-inhibitory potency analyses using 7 p-benzoquinones and 33 substituted phenols. Their effects on its ubiquinol-1 oxidase activity were compared with those on the cytochrome bd complex in E. coli and on cytochromes o and alpha 1 in Acetobacter aceti. They showed similar structural properties of the QL site, although cytochrome o was more sensitive to 4-cyanophenols, suggesting a specific interaction of the hydrogen bond-accepting cyano group with the binding pocket. Replacing one of the methyl groups of 2,6-dimethyl-p-benzoquinone, which is the most potent competitive inhibitor, with an ethyl group markedly decreased the inhibitory activity, indicating that the QL site specifically recognizes one C = O group with two methyl groups as the ortho-substituents. In substituted phenols, ortho-chlorine substituents were the most effective in recognition, and the electron-withdrawing ability of the para-substituent determined an inhibitory potency, probably by stabilizing an anionic form. Based on these observations, we postulate that the QL site of the cytochrome bo complex asymmetrically recognizes exogenous ligands and that this property accounts for the sequential electron transfer from ubiquinols to the low-spin heme.
Benzoquinones↗
Identification of a novel quinone-binding site in the cytochrome bo complex from Escherichia coli.
The cytochrome bo complex is a heme BO-type heme-copper quinol oxidase in the aerobic respiratory chain of Escherichia coli and functions as an electron transfer-linked proton pump. To study the protein-mediated electron transfer from substrates to metal centers, we carried out quantitative and qualitative analyses of a bound quinone in the purified oxidase and found that it has a novel high affinity ubiquinone-binding site distinct from the quinol oxidation site. Enzymatic and spectroscopic studies suggest that the quinone-binding site is located close to both the quinol oxidation site in subunit II and low-spin heme B in subunit I. The quinone-binding site of a bound ubiquinone-free oxidase was reconstituted with the potent quinol oxidation site inhibitor 2,6-dichloro-4-nitrophenol, which decreased the Vmax value of the ubiquinol-1 oxidase activity to one-fourth of the control activity. These results indicate that the quinone-binding site is essential for the catalytic functions of the cytochrome bo complex and mediates electron transfer from the quinol oxidation site to the low-spin heme.
Air↗