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Biomedical subjects

H Sawada

Publications and source records attributed to H Sawada.

At least 469 records · Page 26Linked to original sources
PubMed1985

Effect of antimetabolites and thymidine blockage on the induction of differentiation of HL-60 cells by retinoic acid or 1 alpha,25-dihydroxyvitamin D3.

Induction of differentiation of the HL-60 human promyelocytic leukemia cell line by retinoic acid or 1 alpha,25(OH)2D3 was analyzed under the condition in which cellular DNA synthesis was inhibited by several antimetabolites or blocked by thymidine. The results demonstrate that differentiation occurs in the absence of DNA synthesis and that some inhibitors of DNA synthesis may enhance the differentiation of HL-60 cells by the above inducers. Among the antimetabolites used, the enhancement of induction of differentiation by hydroxyurea was shown to be more effective than that of Ara-C or aphidicolin. The effect of thymidine blockage was similar to that of hydroxyurea. These different effects may be due to the different points at which the cell cycle is blocked by these agents. These results seem to be common in both the differentiation of the granulocytic line induced by retinoic acid and of the macrophage line induced by 1 alpha,25(OH)2D3. The present study also suggests that combination treatment with the inhibitor of DNA synthesis and the inducer of differentiation could be beneficial in the clinical therapy of leukemia. The mode of action of clinical low-dose Ara-C treatment is also discussed.

Antibiotics, Antineoplastic↗
PubMed1985

[Distribution of left ventricular hypertrophy and electrocardiographic findings in patient with so-called apical hypertrophic cardiomyopathy].

The distribution of left ventricular hypertrophy determined by two-dimensional echocardiography was compared with the ECG findings of 15 patients with so-called apical hypertrophic cardiomyopathy. In most patients, hypertrophy was localized from the anterior septum at the mid-level of the left ventricle to the apex. Giant negative T waves and ST depressions were observed in II, III, aVF and V4-6 in all cases. Negative U waves in the same leads and prolongation of the QTc were also observed in most cases. The cause of these ECG abnormalities was unknown, but ST-T changes and negative U waves may be related to marked, localized hypertrophy of the apex. The depth of the negative T waves and the ST segments changed significantly by hour, from day to day, or from year to year. However, these changes were not associated with significant changes in blood pressure, cardiothoracic ratio, physical condition or therapy. The cause of these changes was unknown, but alterations in activity of the sympathetic nervous system may be one possible cause. In patients with monthly or yearly changes in ST-T, the progression of hypertrophy may also be the cause. ST-T variations revealed in this study might be one of the causes for the different incidences of giant negative T waves in the reports with apical hypertrophic cardiomyopathy. In some patients, an exercise test was positive, but, the coronary angiogram and left ventriculogram were normal for all patients.

Adult↗
PubMed1985

[Three dimensional reconstruction of the human left ventricle from multiple cross-sectional echocardiograms: comparison with biplane cineventriculography using Simpson's rule].

A system for reconstructing three-dimensional images of the left ventricle from randomly-recorded multiple short-axis two-dimensional images was developed. This system consisted of a real-time phased array sector scanner, a transducer-locating arm system for registering the spatial coordinates of the images, and a digitizer-computer system for digitizing the endocardial edge to display the reconstruction image and to calculate the left ventricular volume. The clinical applicability of this system was assessed by comparing the calculated left ventricular volumes by this system (3DE) with those measured by cineventriculography (LVG) for 10 patients. For end-diastolic volumes (EDV) determined by 3DE and LVG, the linear regression equation was EDV (LVG) = 1.07 EDV (3 DE)-3.4, SEE = 19.0 ml, r = 0.959. For end-systolic volumes (ESV), it was ESV (LVG) = 1.16 ESV (3 DE)-6.0, SEE = 13.1 ml, r = 0.970, and for stroke volumes (SV), it was SV (LVG) = 0.70 SV (3 DE) + 32.3, SEE = 24.5 ml, r = 0.606. This method was considered applicable to clinical non-invasive measurements of left ventricular volumes. Digitized images were easily processed by a computer, and much informations, such as volumes, shapes and wall motion, were assessable.

Cardiac Volume↗
PubMed1984

Purification and characterization of two forms of microsomal carbonyl reductase in guinea pig liver.

Two forms of microsomal carbonyl reductase, solubilized in Triton X-100, were purified to homogeneity from the liver of male guinea pigs, primarily by affinity, DEAE-Sephacel, gel-filtration and hydroxyapatite chromatography. The major form was a tetrameric glycoprotein of single subunits of Mr 32000 and a pI value of 7.0; another minor form was a monomeric protein with Mr 34000 and a pI value of 7.8. The enzymes were immunologically distinct. Although the enzymes showed similar substrate specificity for exogenous aldehydes and ketones and apparently absolute cofactor specificity for NADPH, their specificity for natural carbonyl compounds differed. The major form irreversibly reduced 5 alpha- and 5 beta-dihydrotestosterones, menadione and lauryl aldehyde with low Km values of 10-70 microM, whereas the minor form not only reduced 17-oxosteroids, of which 3 alpha-hydroxy-5 beta-androstan-17-one was the best substrate, but also oxidized 17-hydroxysteroids in the presence of NADP+. The two forms of carbonyl reductase also exhibited different sensitivity to heavy metal ions, dicoumarol, tetramethyleneglutaric acid, phenobarbitone and corticosteroids.

Alcohol Oxidoreductases↗
PubMed1984

Immunological identification of soluble carbonyl reductase with testosterone 17 beta-dehydrogenase (NADP+) in guinea pig liver and kidney.

Antiserum was produced against one of two carbonyl reductases purified from guinea pig liver cytosol to identify the enzymes as testosterone 17 beta-dehydrogenase isozymes. Immunoelectrophoresis and immunoprecipitation with the antiserum indicated that the two reductases had common antigenic sites. The antiserum inhibited most of both carbonyl reductase and testosterone 17 beta-dehydrogenase activities in the purified reductases and in cytosols of liver and kidney.

17-Hydroxysteroid Dehydrogenases↗
PubMed1984

Purification and characterization of trypsin-like enzyme from sea urchin eggs: substrate specificity and physiological role.

A trypsin-like enzyme has been purified to homogeneity from eggs of the sea urchin, Strongylocentrotus intermedius. The purified enzyme efficiently hydrolyzed Z-Phe-Arg-4- methylcoumaryl -7-amide (MCA) and Pro-Phe-Arg-MCA among 12 peptidyl-Arg (or Lys)- MCAs . The substrate specificity of the enzyme was closely similar to that of the enzyme activity in the egg cortical granule exudate. Among various peptidyl-argininal (Arg-H) derivatives, Z-Phe-Arg-H and Z-Phe-Leu-Arg-H showed the strongest inhibition against both the activity of the purified enzyme and the elevation of vitelline coat. Thus, the trypsin-like enzyme of sea urchin possesses a narrow substrate specificity and participates at least in the elevation of vitelline coat during fertilization.

Animals↗
PubMed1984

Purification and characterization of two types of trypsin-like enzymes from sperm of the ascidian (Prochordata) Halocynthia roretzi. Evidence for the presence of spermosin, a novel acrosin-like enzyme.

Two types of trypsin-like proteases, spermosin and acrosin, have been highly purified from spermatozoa of the ascidian (Prochordata) Halocynthia roretzi by a procedure including diethylaminoethylcellulose chromatography, Sephadex G-100 gel filtration, and soybean trypsin inhibitor-immobilized Sepharose 4B chromatography. Each purified preparation was judged to be homogeneous on the basis of chromatographic analysis and sodium dodecyl sulfate-gel electrophoresis. The molecular weights of spermosin and acrosin were estimated to be 27,000 and 32,000-34,000, respectively, by gel electrophoresis in sodium dodecyl sulfate. The isoelectric point of the former was 6.5, while that of the latter was 5.5. Non-ionic detergents, e.g. Brij 35, showed marked stabilizing effects on the purified enzymes. Both of these enzymes had pH optima between 8.5 and 9.0, and their activities were enhanced by the addition of calcium chloride. The enzymes were inhibited by diisopropyl fluorophosphate, phenylmethanesulfonyl fluoride, leupeptin, antipain, soybean trypsin inhibitor, aprotinin, ovomucoid, valyl-prolyl-arginyl-chloromethane, glycyl-valyl-arginyl-chloromethane, p-aminobenzamidine, benzamidine, zinc chloride, and mercuric chloride. Lima bean trypsin inhibitor and tosyl-lysyl-chloromethane strongly inhibited acrosin, but not spermosin. While the substrate specificity of acrosin was rather broad, that of spermosin was very narrow; the latter enzyme hydrolyzed only t-butyloxycarbonyl-valyl-prolyl-arginine 4-methylcoumaryl-7-amide among 12 peptidyl-arginine (or lysine) 4-methylcoumaryl-7-amides tested. Thus, the ascidian spermatozoa possess at least two proteases, acrosin and spermosin; the former shows the properties closely related to those of mammalian acrosin (EC 3.4.21.10), but the latter is a unique type of acrosin-like enzyme in respect to the substrate specificity and inhibitor susceptibility.

Acrosin↗
PubMed1984

Evidence for the participation of two sperm proteases, spermosin and acrosin, in fertilization of the ascidian, Halocynthia roretzi: inhibitory effects of leupeptin analogs on enzyme activities and fertilization.

Ten kinds of argininal-containing compounds were examined for their inhibitory effects on the fertilization of the solitary ascidian and on the activities of acrosin and spermosin, trypsin-like proteases isolated from spermatozoa of this animal. Benzyloxycarbonyl-Val-Pro-argininal (I) and benzyloxycarbonyl-Phe-Leu-argininal (II) showed the strongest inhibition on the fertilization. Leupeptin (acetyl-Leu-Leu-argininal, III) was ranked next (I, II greater than III). The activity of ascidian acrosin was susceptible to most of the compounds, among which II was the best inhibitor and followed with I and III (II greater than I, III). Spermosin suffered significant inhibition only with I and II (I greater than II). These results suggest that not only acrosin but also spermosin is involved in fertilization of the ascidian.

Acrosin↗
PubMed1984

Differentiation of mouse leukemic M1 cells induced by polyprenoids.

We screened several synthetic polyprenoids about their capacity of cell differentiation using mouse myeloid leukemic M1 cells, and found that 3, 7, 11, 15, 19,-pentamethyleicosa-2, 6, 10, 14, 18-pentaenol (Geranyl Farnesol) could induce the differentiation of M1 cells into macrophage-like cells. The optimal concentration of this compound for its induction capacity was approximately 2 X 10(-5) M. The induced differentiation related markers were morphological change in M1 cells, Fc receptors for IgG (Fc gamma), and non-specific esterase activity. However, phagocytic activity was poorly induced. This suggests that most of Geranyl Farnesol treated cells may be retained functionally incomplete macrophages. The presence of cycloheximide at 1 X 10(-7)M or the incubation of M1 cells at 4 degrees C completely blocked the induction of Fc gamma, suggesting the induction of Fc gamma required protein synthesis. The treatment of M1 cells with Geranyl Farnesol resulted in suppression of DNA and RNA synthesis. Further analysis of RNA metabolism suggested that the suppression of RNA synthesis was mainly due to the decrease of rRNA. On the other hand the synthesis and turnover of polyA-containing RNA (mRNA) rather increased.

Animals↗
PubMed1984

Connectin filaments in stretched skinned fibers of frog skeletal muscle.

Indirect immunofluorescence microscopy of highly stretched skinned frog semi-tendinous muscle fibers revealed that connectin, an elastic protein of muscle, is located in the gap between actin and myosin filaments and also in the region of myosin filaments except in their centers. Electron microscopic observations showed that there were easily recognizable filaments extending from the myosin filaments to the I band region and to Z lines in the myofibrils treated with antiserum against connectin. In thin sections prepared with tannic acid, very thin filaments connected myosin filaments to actin filaments. These filaments were also observed in myofibrils extracted with a modified Hasselbach-Schneider solution (0.6 M KCl, 0.1 M phosphate buffer, pH 6.5, 2 mM ATP, 2 mM MgCl2, and 1 mM EGTA) and with 0.6 M Kl. SDS PAGE revealed that connectin (also called titin) remained in extracted myofibrils. We suggest that connectin filaments play an important role in the generation of tension upon passive stretch. A scheme of the cytoskeletal structure of myofibrils of vertebrate skeletal muscle is presented on the basis of our present information of connectin and intermediate filaments.

Animals↗
PubMed1984

Purification and characterization of a purple acid phosphatase from rat spleen.

An acid phosphatase species which is activated by Fe2+ was purified 3,700-fold from rat spleen by chromatography on columns containing Blue-Sepharose, concanavalin A-Sepharose, Sephadex G-100, and CM-Sephadex. The enzyme hydrolyzed aryl phosphates, nucleoside di- and triphosphates, phosphoproteins, and thiamine pyrophosphate with Km values of 10(-4) to 10(-3) M at an optimal pH of 5.0-5.8. Co-purification of the acid phosphatase and acid phosphoprotein phosphatase indicated that they were identical. The purified enzyme was glycoprotein in nature, showing four heterogeneous forms on acid polyacrylamide gel electrophoresis (pI values, 7.8, 8.0, 8.3, and 8.5), but it gave a molecular weight of 33,000 on sodium dodecyl sulfate-gel electrophoresis and gel permeation chromatography. The enzyme had a purple color (lambda max 545 nm) and contained 2 iron atoms per enzyme molecule. Among reductants, ascorbic acid and Fe2+ were the best activators, although their combined effect was not additive. Fe2+ and ascorbic acid both changed the purple enzyme into the same active form (lambda max 515 nm), giving almost the same kinetic constants for substrates and for inhibitors such as molybdate, phosphate and fluoride. However, low concentrations of Fe2+, from 0.01 mM to 1.0 mM, immediately and reversibly activated the enzyme, whereas high concentrations of ascorbic acid over 1 mM were required for maximal activation, which was slow and irreversible.

Acid Phosphatase↗
PubMed1984

Molecular size and shape of beta-connectin, an elastic protein of striated muscle.

Connectin is an elastic protein of vertebrate striated muscle, and consists of doublet components, alpha and beta (also called titins 1 and 2). In the present study, beta-connectin isolated in the native state was investigated in order to characterize its molecular size and shape. The molecular weight was approximately 2.1 X 10(6) (SDS gel electrophoresis) or 2.7 X 10(6) (sedimentation equilibrium). The sedimentation coefficient (SO20, w) was 17S in 0.1 M phosphate buffer, pH 7.0. The intrinsic viscosity measured in an Ostwald-type viscometer was 1.8 dl/g. However, the viscosity was greatly dependent on the velocity gradient, and at a very low velocity gradient of 0.0007 s-1, a solution of connectin (0.3 mg/ml) showed a viscosity value of 17,000 cp. Flow birefringence measurements suggested a length distribution ranging from 300 to 450 nm. Electron microscopic observations revealed that connectin is a long flexible filament and the peaks of frequency of length distribution were at 150, 300, 450, and 600 nm. It was tentatively assumed that the connectin molecule is 300-400 nm long and 34-38 nm wide. It is likely that beta-connectin is derived from alpha-connectin, which has an apparent molecular weight of 2.8 X 10(6).

Animals↗
PubMed1984

The effect of low dose Ara-C in acute nonlymphoblastic leukaemias and atypical leukaemia.

Nine patients with nonlymphocytic leukaemia and one patient with refractory anaemia with excess of blasts (RAEB) were treated subcutaneously with Ara-C at a low dose of 10 mg/m2/12 h; complete remission was obtained in seven patients. In all cases severe pancytopenia was observed during treatment. We measured the concentration of Ara-C in serum, and found that the maximum concentration reached a peak (52-132 ng/ml; mean 84.2 ng/ml) at 15 min following injection. These concentrations can be considered sufficient to inhibit DNA synthesis. Primary short-term culture of human leukaemic cells with low dose Ara-C was also performed, and differentiation of leukaemic cells was observed for several types of leukaemic cells. The in vitro findings corresponded to the observed clinical effects. From the above results, the action of low dose Ara-C may have resulted from a combination of two different mechanisms, its cytostatic effect and its differentiation-inducing effect.

Adult↗
PubMed1984

Computer analysis of cross sectional echocardiogram for quantitative evaluation of left ventricular asynergy in myocardial infarction.

Left ventricular asynergy in myocardial infarction was assessed quantitatively by computer analysis of the cross sectional echocardiogram. Short axis cross sectional images of the left ventricle at the levels of the mitral valve, papillary muscle, and apex were recorded by a phased array sector scanner in 30 patients with healed myocardial infarction and 15 normal controls. Endocardial and epicardial short axis images of the left ventricle were transferred from video tape to a minicomputer through the interface circuits, then digitised and processed automatically by a minicomputer. Automatic edge detection of the endocardial and epicardial wall was performed by applying sequential steps including smoothing, second derivative technique, dynamic thresholding, and approximation of boundaries by a spline curve. To quantify regional wall motion, the short axis cross sectional left ventricular wall of each level was divided into eight octants with eight axes at 45 degrees angles from the initial standard axis which was constructed from the geometric centre of the end diastolic left ventricular cavity to the posterior end of the right side of the interventricular septum. Segmental hemiaxis, segmental area, segmental wall thickness, and those changes during cardiac cycle were measured and calculated in each segment automatically by a computer. Regional contractility of the left ventricle was evaluated by percentage systolic changes of the segmental hemiaxis, area, and wall thickness. These values were significantly reduced in the infarcted left ventricular wall as defined by left ventriculography and electrocardiography. Moreover, percentage hemiaxis changes obtained by quantitative left ventriculography described by Herman and colleagues correlated well with those using our analytical method of cross sectional echocardiography in the corresponding segments. The geometric centre of the left ventricular cavity determined by the computer moved slightly towards the anterior wall during systole in normal subjects, possibly reflecting the anterior swinging motion of the heart. The geometric centre of the left ventricular cavity in myocardial infarction moved towards the infarcted wall, showing that the floating reference system was inferior to the fixed reference system for the quantification of abnormal wall motion in myocardial infarction. In conclusion, a computer analysis of the short axis cross sectional echocardiogram of the left ventricle using the fixed reference system has shown its ability to evaluate left ventricular contraction abnormalities, especially systolic wall thickening, which is relatively free of arbitrary interpretation of the wall motion caused by the anterior swinging motion of the heart.

Adult↗
PubMed1984

Computerized processing of two-dimensional echocardiograms for the quantification of left ventricular regional contractility.

A new practical method of computer digital image processing of two-dimensional echocardiograms was developed for the quantification of the left ventricular regional contractility. Short axis, cross-sectional images of the left ventricle at the levels of the mitral valve, papillary muscle and apex were recorded by a phased array sector scanner. The echo data recorded on video tape were transfered to a minicomputer through the interface circuits and digitized and processed automatically. Automatic edge detection of the endocardial and epicardial walls was performed by applying sequential steps, including smoothing, dynamic thresholding, region growing and filling small holes. The rationale for edge detection depended upon the assumptions that the abrupt changes of the gray levels occurred at the boundaries and that the points with the maximum gradient values are boundaries of the left ventricular wall. Best-fit contours of endocardial and epicardial edges were drawn by fitting a spline. The short axis cross-sectional left ventricular wall at each level was divided into eight segments, with the center of gravity of enddiastolic left ventricular cavity and the axis connecting this with the posterior end of the right side of the septum being used as the reference point and line. The segmental hemiaxis, area and wall thickness were measured every 33 msec from end-diastole during the cardiac cycle and the systolic percent changes were calculated automatically by a computer. Regional contractility of the left ventricle was evaluated by systolic percent changes of the segmental hemiaxis, area and wall thickness. The measured values in a patient with dilated cardiomyopathy were lower than those of a normal subject, probably reflecting myocardial damage of the left ventricle. Although there are some points to be improved, including a better system for transferring echo data to the computer and the evaluation of the validity of this fixed reference system, it is likely that computer analysis of the short axis cross-sectional echocardiogram of the left ventricle will be useful in a clinical setting.

Cardiomyopathy, Dilated↗
PubMed1984

The basement membrane of bovine corneal endothelial cells in culture with beta-aminopropionitrile: biosynthesis of hexagonal lattices composed of a 160 nm dumbbell-shaped structure.

Bovine corneal endothelial cells maintained in culture produced an extracellular matrix on their basal surface. In the presence of beta-aminopropionitrile (beta-APN) (100-500 micrograms/ml), an inhibitor of cross-linking, this extracellular matrix contained hexagonal lattices of 150 nm periodicity. The lattice was composed of round densities 60 nm in diameter comprising the nodes of the lattice and rod-like structures 40 nm in thickness comprising its sides. This structure is almost identical to that of bovine Descemet's membrane in situ. The lattice was produced only in the presence of beta-APN. By freeze-etch replica and negative staining of 1 day cultures, the unit component of the lattice appeared to be a novel 160 nm long dumbbell-shaped symmetrical structure. The central rod of the dumbbell-shaped structure was 80 nm long and 20 to 50 nm in diameter with round ends (40-50 nm). In the rod 2 nm fibrillar substructures were discerned by negative staining. The rod-like central portion was resistant to trypsin digestion whereas the round ends were digested by it. Both structures disappeared after bacterial collagenase digestion. By immunoblotting the extracellular matrix contained 160kd and 180kd bands which bound anti-type IV collagen antibodies and a 140kd band which bound anti-type III collagen antibodies. The lattice area was also positively stained with these antibodies by immunoperoxidase. The findings strongly suggest that the hexagonal lattice of bovine Descemet's membranes in situ is composed of this collagenous structure.

Aminopropionitrile↗