[Biochemical mechanisms of the DNA cleavage induced by NCS-chromophore].
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Biomedical subjects
Publications and source records attributed to K Ohtsuki.
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Ginger proteases in ginger rhizome (Zingiber officinale roscoe) were extracted from the ginger acetone powder and purified on DEAE-Sepharose and Sephadex G-75 columns. Before the purification, excess p-chloromercuribenzoate was added to the enzymes to prevent their autodigestion. The mercuribenzoate-proteases were further purified and fractionated by isoelectric focusing in Ampholine of pH 3-10 or pH 4-6. The proteases were fractionated into three components by the isoelectric focusing, having pI value of 4.5, 4.6 and 4.8 respectively. All these proteases had a molecular mass of 29,000 as measured by SDS-polyacrylamide gel electrophoresis and by TSK G2000SW XL gel chromatography. The Ampholine in the purified enzymes can quickly be removed by the gel chromatography of TSK G2000SW. Some divalent metal ions, such as Hg2+, Cu2+, Cd2+, and Zn2+, strongly inhibited these purified enzymes.
Two human type V collagen sub-molecular species, designated [alpha 1(V)]2 alpha 2(V) and alpha 1(V)alpha 2(V)alpha 3(V), were purified chromatographically from a commercially available preparation, in which cystine-rich collagenous contaminants were contained, with a column packed with Fractogel EMD SO3-. From bovine crude preparations, the [alpha 1(V)]2 alpha 2(V) form free from the collagenous contaminants was purified. Type V collagen subunit chains were isolated from each type V collagen molecule by anion-exchange HPLC with a Bakerbond PEI Scout column. The highly purified human type V collagen molecules and their subunit chains were used to examine the inhibitory effect on human umbilical vein endothelial cell proliferation. It was confirmed that the alpha 1(V) chain has inhibitory activity and it was found that the inhibitory effect of the [alpha 1(V)]2 alpha 2(V) form is stronger than that of the alpha 1(V)alpha 2(V)alpha 3(V) form and that the alpha 3(V) chain has no inhibitory activity.
A 96-kDa glycyrrhizin (GL)-binding protein (gp96) was purified to apparent homogeneity from an aqueous extract of soybeans by means of successive DEAE-cellulose column chromatography, gel filtration on Superdex 200pg, GL-affinity column chromatography, and ion-exchange chromatography on a Mono S column (HPLC). The protein was identified as a GL-binding protein since it specifically binds to [3H]GA. Moreover, it is a lipoxygenase (an enzyme that catalyzes the oxygenation of unsaturated fatty acids) since (i) it displays lipoxygenase (LOX) activity at pH 6.5; (ii) it is recognized on Western blot analysis by antibodies against LOX-1 and LOX-2; and (iii) the sequence of the N-terminal 21 amino acid residues (SNDVYLPRDEAFGHLKSSDFL) of a 42-kDa fragment (p42) proteolytically generated from gp96 is identical to a sequence of soybean LOX-3. In addition, GL, glycyrrhetinic acid (GA) and soyasaponin beta g slightly inhibited LOX activity of the purified gp96 fraction, whereas oGA (a GA derivative) greatly inhibited its activity. Furthermore, CK-II catalyzed phosphorylation of gp96 was stimulated significantly by GL at doses between 1 and 10 microM, but this phosphorylation was inhibited completely by 50 microM GL. All these results taken together suggest that (i) gp96 purified from soybeans as a GL-binding protein belongs to the LOX family; and (ii) triterpenoid saponins, including GL, are involved in the regulation of the activities of CK-II and LOXs in plants, such as soybeans and roots of liquorice, which contain large quantities of saponins.
The entire nucleotide sequence of nylon oligomer degradative plasmid pOAD2 from Flavobacterium sp. KI723T1 was determined. pOAD2 comprises 45519 bp, with a 66.6 mol% G+C content. The precise loci of the four nylon oligomer degradation genes, namely nylA (6-aminohexanoate-cyclic-dimer hydrolase gene), nylB (6-aminohexanoate-dimer hydrolase), nylB' (a gene having 88% homology to nylB) and nylC (endo-type 6-aminohexanoate oligomer hydrolase), and five IS6100 elements were identified on this plasmid. Comparison of the sequence of pOAD2 with those in the GenBank and EMBL databases revealed that the deduced amino acid sequences from eight regions of pOAD2 had significant similarity with the sequences of gene products such as oppA-F (oligopeptide permeases), ftsX (filamentation temperature sensitive), penDE (isopenicillin N-acyltransferase) and rep (plasmid incompatibility). A functional map of pOAD2 is presented.
Myocardial sympathetic nerve function can be evaluated by 123I-metaiodobenzylguanidine (MIBG) scintigraphy. Congestive heart failure is closely related to myocardial sympathetic nerve function. This study evaluated the severity of congestive heart failure in 30 patients with valvular heart disease [aortic regurgitation (AR): n = 20, mean age = 70 +/- 13 years; mitral regurgitation (MR): n = 10, mean age = 61 +/- 18 years], who had chronic heart failure by MIBG myocardial scintigraphy. Single photon emission computed tomography (SPECT) and anterior planar myocardial images were obtained 15 minutes (initial images) and 4 hours (delayed images) after injection of MIBG (111MBq). Defect score was determined by the delayed SPECT images visually as a semi-quantitative index. Myocardial MIBG uptake was quantified by the heart to upper mediastinum uptake ratio on the delayed anterior planar images (H/M) and mean cardiac MIBG washout rate during 4 hours was calculated from the bull's eye display data (clearance). These indices were compared with the NYHA class and echocardiographic findings of the patients. MIBG regional defect in the delayed image was most frequently seen in the inferoposterior wall, and defect score and clearance were significantly higher and the H/M ratio was significantly lower in NYHA class III patients than in class II patients. In patients with AR, clearance significantly correlated with left ventricular end-systolic dimension. In patients with MR, both the H/M ratio and clearance significantly correlated with left atrial dimension. Defect score, H/M, and clearance were closely related to the severity of AR and MR. These results indicate that MIBG scan can be used to assess the severity of valvular heart disease.
The aim of this study was to elucidate the characteristic feature of myocardial imaging with 123I-labeled 15-(p-iodophenyl)-3R,S-methylpentadecanoic acid (BMIPP) in the patients with hypertrophic cardiomyopathy (HCM). In 26 patients with asymmetric septal hypertrophy (ASH), the imaging data were acquired for 15 minutes after the injection of 123I-BMIPP by the emission computed tomography (ECT). ECT image was divided into 17 segments to score the severity of the defect in each segment using a 5-point grading system from score 3 to score -1; score 3 = severely decreased tracer uptake, score 2 = moderately decreased tracer uptake, score 1 = mildly decreased tracer uptake, score 0 = normal and score -1 = increased tracer uptake. Reduced uptake (Defect Score > or = 2) was frequently observed in septal portion of anterior wall (65%), septal portion of posterior wall (62%) and apical wall (73%). Defect score was higher in septal portion of anterior wall (p < 0.001), septal portion of posterior wall (p < 0.01) and apical wall (p < 0.01) than in the ventricular septum. This result indicates that in hearts with ASH, 123I-BMIPP image reveals severely impaired fatty acid metabolism in these regions. With the reference of the previous report about histologic features in necropsy hearts with HCM, myocardial fatty acid metabolic disorder shown by reduced 123I-BMIPP uptake is closely related to the histological abnormalities in hearts with HCM.
Myocardial perfusion and fatty acid metabolism may be unpaired in the patients of vasospastic angina (VSA), because abnormal regional wall motion of left ventricle has been shown in some cases of VSA without apparent history of myocardial infarction. To study the clinical utility of 123I-BMIPP scintigraphy in diagnosis of myocardial ischemia in VSA, both 123I-BMIPP (rest) and 201T1 (exercise) SPECT were performed in the 20 patients of VSA diagnosed by coronary angiography. Defect scores were calculated visually from the 17 segments of myocardial images and were compared with patient's anginal history, period from last attack, numbers of attack, left ventricular (LV) ejection fraction and severity of regional LV wall motion abnormality. 123I-BMIPP SPECT images showed decreased tracer uptake in 14 cases of 20 (70%) VSA patients. Exercise 201T1 SPECT images showed decreased tracer uptake in 3 cases of 20 (15%) of patients. Severity of regional LV wall motion abnormality was correlated with defect score of BMIPP. Though total defect score of BMIPP did not correlate with patient's anginal history, number of symptoms and LV ejection fraction, correlated inversely with period from last attack. It was suggested that 123I-BMIPP myocardial SPECT images in VSA patients showed "memories" of myocardial ischemic damages induced by vasospasm. In summary, 123I-BMIPP myocardial SPECT images could be a useful test for diagnosis and evaluation of VSA.
A 55-year-old man with pheochromocytoma was examined by 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy before and after resection of the tumor. MIBG images showed decreased uptake in infero-posterior wall before operation. The heart to upper mediastinum uptake ratio was low at the delayed anterior planar image, and mean MIBG clearance from the left ventricle was increased. These abnormal scintigraphic findings improved after resection of the tumor. We thought that these abnormal MIBG findings were not due to abnormal cardiac sympathetic nerve function, because ECG, chest X-ray, UCG and 201Tl myocardial scintigram did not reveal any abnormality. It may be presumed that these abnormal MIBG findings were caused by high plasma catecholamines concentration. The mechanism of abnormal MIBG findings of the heart remains uncertain in various heart diseases. MIBG findings in this case with pheochromocytoma before and after resection may contribute to interpretation of the kinetics of MIBG in heart.
Using ssDNA-cellulose column chromatography, a 34 kDa ribonucleoprotein (p34) has been purified from a 0.4 M KCl crude extract of spinach chloroplasts as an effective phosphate acceptor for casein kinase II (CK-II) in vitro. Monomeric and oligomeric CK-IIs were copurified with p34 by the column chromatography and the kinases were separated from p34 by means of Mono Q column chromatography. It was found that (i) the purified p34 (pI 4.9) was phosphorylated specifically by CK-II in vitro; and (ii) similar polypeptides, such as p35 (pI 4.7) and p39 (pI 4.9) in maize and p33 (pI 4.7) in liverwort, were detected as ssDNA-binding chloroplast proteins phosphorylated by CK-II in vitro. The findings suggest that (i) RNPs that function as phosphate acceptors for CK-II exist commonly in chloroplasts among plant cells; and (ii) the physiological activity of RNPs is regulated by their specific phosphorylation by CK-II in chloroplasts.
By means of successive GL-affinity and Mono S column chromatographies (HPLC), a 100 kDa GL-binding protein (gp100) was purified from the partially purified CK-II fraction of EAT cells as an effective phosphate acceptor for CK-II. It was found that (i) gp100 (pI 9.0) is copurified with CK-II, Hsp-90 and p34 or p70; (ii) gp100 cross-reacts with anti-human GR; (iii) phosphorylation of gp100 by CK-II is significantly stimulated by 1 microM GL or 0.3 microM oGA; and (iv) GL as well as DEX inhibit it at doses above 3 microM. Data are provided to suggest that the GL-induced selective inhibition of the CK-II catalyzed phosphorylation of gp100 may be involved in the anti-inflammatory effects of GL.
To evaluate the clinical utility of 123I-labelled 15-(p-iodophenyl)-3-R, S-methylpentadecanoic acid (123I-BMIPP), myocardial scintigraphy using 123I-BMIPP was performed in 13 patients with hypertrophic cardiomyopathy (HCM), and the findings were compared with those of 201Tl. The uptake of each tracer was scored visually from 4 (increased) to 0 (severely decreased) in a total of 13 segments in the apical and basal short axial images, and the long axial images of myocardial single photon emission tomography (SPET). In the comparison of the early images with 123I-BMIPP (taken 15 min after injection) and the 201Tl perfusion images, 70% of the segments showed uncoupled uptake, with the uptake of 123I-BMIPP more often being less. In the hypertrophic regions, 123I-BMIPP demonstrated significantly less uptake than 201Tl, especially in the delayed images (taken 3 h after injection). In the nonhypertrophic regions, there was no significant difference in uptake between the 123I-BMIPP early images and the 201Tl images; the 123I-BMIPP delayed images, however, demonstrated significantly less uptake than the 201Tl images. These results suggest that the uncoupling between the 123I-BMIPP and 201Tl uptakes and the washout (the relative decrease in activity from early to delayed images of 123I-BMIPP) reflect abnormal myocardial fatty acid metabolism in HCM.
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The nucleotide sequence of repeated sequence I, which appears in five regions on nylon oligomer-degrading plasmid pOAD2, harbored in Flavobacterium sp. strain K172, was determined. The five regions of repeated sequence I had 880 bp of identical sequence, and the sequence was identical to that of IS6100, an insertion sequence classified in the IS6 family, initially found in Mycobacterium fortuitum. Sequences homologous to that of IS6100 were found for another nylon oligomer-degrading plasmid, pNAD2, harbored in Pseudomonas sp. strain NK87, by Southern hybridization experiments.
Histones H2A and H2B were found to be glycyrrhizin (GL)-binding proteins, because (i) the two histones H2A-H2B pairs were isolated selectively from the crude histone preparations of calf thymus by means of GL-affinity column chromatography (HPLC); (ii) phosphorylation of these two histones by A-kinase was remarkably stimulated by native GL or oGA (a derivative of glycyrrhetinic acid) at 20 microM; and (iii) in the crude histone preparations of calf thymus, these two histones were selectively phosphorylated by A-kinase in the presence of both dsDNA and 20 microM oGA or 20 microM GL. The provided data suggest that the GL-induced selective phosphorylation of histones H2A and H2B by A-kinase may be implicated in the transcriptional activation involved in the biological activities of the drug.
The antihypertensive effects of (+-)-(cyclohexyloxycarbonyloxy)ethyl2-ethoxy-1-[[2'-(1H- tetrazol-5- yl)biphenyl-4-yl]methyl]-1-H-benzimidazole-7-carboxylate (TCV-116), an angiotensin II (AII) subtype-1 receptor antagonist, were studied in various hypertensive and normotensive rats, using 2-n-butyl-4-chloro-5-hydroxymethyl-1-[(2'-(1H-tetrazol-5-yl)bip hen yl-4- yl)methyl]-imidazole, potassium salt (losartan) as a reference compound. TCV-116 is a prodrug, which is converted in vivo to the active component, 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl)]methyl]-1H- benzimidazole-7-carboxylic acid (CV-11974). In spontaneously hypertensive rats (SHR) p.o. TCV-116 (0.1 mg/kg) demonstrated a sustained antihypertensive effect that lasted for more than 10 hr and the dose that reduced the blood pressure by an average of 25 mm Hg for 24 hr (ED25), was 0.68 mg/kg. Intravenous CV-11974 reduced the blood pressure with an ED25 of 0.0027 mg/kg. Repeated p.o. administration of TCV-116 (1 mg/kg) to SHR once daily for 2 weeks reduced the blood pressure by 30 to 50 mm Hg over 24 hr without any heart rate changes. The antihypertensive effects of TCV-116 correlated well with the inhibition of angiotensin II-induced contractile responses of aortic strips prepared ex vivo after p.o. administration of TCV-116. Oral TCV-116 had a sustained antihypertensive effect with ED25 of 0.03 and 0.23 mg/kg in two-kidney, one-clip and one-kidney, one-clip hypertensive rats, respectively, and was much more potent in SHR and renal-hypertensive rats than losartan.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertrophic cardiomyopathy (HCM) is known to have the impairment of myocardial perfusion as well as irregularly hypertrophic myocardium. To evaluate myocardial perfusion and ventricular shape in HCM, 99mTc-Tetrofosmin scintigraphy was performed after exercise (Ex) and at resting state (Re) in 10 patients with HCM and was compared with early image (Ea) and delayed image (De) of 201Tl scintigraphy performed after exercise. SPECT images of both 99mTc-Tetrofosmin and 201Tl scintigraphy were analyzed with five scaled visual scores set in 18 segments. The complete concordance ratio between 99mTc-Tetrofosmin (Ex and Re) and 201Tl (Ea and De) images in segmental analysis was 75%. Image quality of 99mTc-Tetrofosmin was seemed to be superior to that of 201Tl scintigraphy. In 9 patients with HCM, 99mTc-Tetrofosmin scintigraphy was performed under the ECG gating and the thickness of septal and free wall was measured. Good correlation was observed with the data by ultrasound cardiography (r = 0.79, p < 0.002 in wall thickness, r = 0.84, p < 0.01 in the ratio of septal wall thickness to free wall thickness). Left ventricular shape (ventricular long axis) was closely resemble to that of left ventriculography by contrast medium. In conclusion, 99mTc-Tetrofosmin scintigraphy is useful for the evaluation of myocardial morphology as well as perfusion abnormality.
A 34 kDa ribonucleoprotein (p34) was purified to homogeneity from a 1.0 M KCl extract of spinach chloroplasts and characterized as an effective phosphate acceptor for casein kinase II (CK-II). The N-terminal 21 residues (W-V-A-Q-T-S-E-E-E-Q-E-G-S-T-N-A-V-L-E-G-E) of p34 were 95% identical with the sequence reported for 28RNP (plastid mRNA 3' end processing factor in chloroplast). Moreover, the findings that DNAs as well as RNAs significantly stimulate the CK-II catalyzed phosphorylation of p34 in vitro and induce its conformational change, suggest that the physiological activity of p34-bound RNA or DNA in chloroplast post-transcriptional regulation is controlled by specific p34 phosphorylation by CK-II.