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Biomedical subjects

H Hanada

Publications and source records attributed to H Hanada.

At least 73 records · Page 4Linked to original sources
PubMed1993

Cloning of the rat aortic smooth muscle Na+/Ca2+ exchanger and tissue-specific expression of isoforms.

The amino acid sequences of two isoforms of the rat aortic smooth muscle Na+/Ca2+ exchanger have been deduced by cloning and sequencing the cDNAs. These isoforms are identical in nucleotide sequence except that one has a 23-amino acid insertion at amino acid position 570. They are highly homologous to the canine cardiac exchanger except for the NH2-terminal portion and part of the large central hydrophilic domain (amino acid residues 570-631). They are 902 and 925 (with the insertion) amino acid long with calculated molecular masses of 100,676 and 103,200 (with the insertion), respectively, if the NH2-terminal 32-amino acid residues are eliminated as a cleaved signal sequence. Amplification of the variable region (amino acids 570-631) of the exchanger by means of the reverse transcriptase-polymerase chain reaction and DNA sequencing revealed that many isoforms of the exchanger are expressed in different rat tissues. The two clones isolated in this study are the predominant isoforms expressed in aorta, stomach, liver, and kidney. In cardiac and skeletal muscles, another isoform is dominant, which is equivalent to the canine cardiac exchanger. In brain, a third type is predominantly expressed. Alignment of the nucleotide sequences of these isoforms and Southern blot analysis of rat genomic DNA suggested that each isoform is generated through alternative splicing of the primary transcript.

Alternative Splicing↗
PubMed1992

Noninvasive detection of left ventricular diastolic dysfunction using M-mode echocardiography to assess left ventricular posterior wall kinetics in hypertrophic cardiomyopathy.

In patients with hypertrophic cardiomyopathy (HC), it is difficult to determine the severity of left ventricular (LV) diastolic dysfunction. Three different patterns of LV posterior wall motion were found by M-mode echocardiography in patients with HC, and the use of these patterns is proposed as a new noninvasive index of the severity of LV diastolic dysfunction. M-mode echocardiograms were recorded prospectively from 35 patients with HC, and the posterior wall motion pattern in late systole and early diastole was classified into the following 3 types: (1) normal motion (n = 9); (2) flat motion--flat motion from late systole to early diastole, followed by rapid backward movement (n = 13); and (3) downward motion--slow backward movement from late systole (n = 13). There were no differences in the severity or type of hypertrophy, LV systolic function and pulsed Doppler indexes of LV filling among these 3 groups. However, LV end-diastolic pressure was increased in the groups with flat (15 +/- 6 mm Hg) and downward (16 +/- 9 mm Hg) motion. Furthermore, the maximal rate of decrease in LV pressure (normal 1,450 +/- 300, flat 1,250 +/- 300 and downward 860 +/- 80 mm Hg/s) and the time constant of LV pressure reduction (normal 60 +/- 15, flat 70 +/- 25 and downward 101 +/- 34 ms) showed a stepwise deterioration from the normal to the flat and then to the downward motion groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1992

Vacuolar type H(+)-ATPase genes: presence of four genes including pseudogenes for the 16-kDa proteolipid subunit in the human genome.

Genes for the human vacuolar type H(+)-ATPase proteolipid (16-kDa) subunit were cloned and their nucleotide sequences were determined. Comparison of the deduced sequences indicated that at least four genes including pseudogenes are present in the human genome. One of them corresponded to that for the 16-kDa subunit expressed in HeLa cells. The coding sequence was separated by two introns. The second intron was located in the DNA segment giving a loop between the second and third transmembrane helices, supporting the idea that the 16-kDa subunit was evolved by gene duplication. The primary sequence determined from the second clone had a termination codon behind the third transmembrane helix. Possible translation products from the other two clones had no putative acidic residues essential for proton transport function of the 16-kDa subunit. Thus, it is interesting to know whether these genes are transcribed, since they may have unique cellular functions.

Base Sequence↗
PubMed1992

Clinical significance of normal cardiac silhouette in dilated cardiomyopathy--evaluation based upon echocardiography and magnetic resonance imaging.

It is generally believed that patients with dilated cardiomyopathy have a large cardiac silhouette on chest roentgenography. Contrary to this general belief, we have recently examined several patients with a dilated left ventricle (LV) on echocardiography but in whom the cardiothoracic ratio (CTR) was within normal limits. To investigate this apparent discrepancy, we evaluated the relationship between LV dimensions, measured on M-mode echocardiography, and CTR in 49 patients with dilated cardiomyopathy. Among these patients, 11 (22%) had a CTR less than 50% and 38 (78%) had a CTR greater than 50%. The spatial orientation (cardiac rotation) of the LV within the thorax was evaluated by magnetic resonance imaging (MRI) in 5 patients with a CTR less than 50% and in 7 patients with a CTR greater than 50%, in comparison with 7 normal controls. In each of these patients, cardiac rotation was assessed from both a transverse and a frontal MRI section. In both groups, LV end-diastolic dimension was greater than 5 cm. Transverse cardiac rotation was 32 +/- 8 degrees in patients with a CTR less than 50%. This was significantly lower than in the 7 normal controls (43 +/- 7 degrees) (p less than 0.05). In patients with a CTR greater than 50%, however, transverse cardiac rotation (55 +/- 5 degrees) was significantly greater than in normal controls (p less than 0.01). No differences in frontal cardiac rotation was observed between the 2 groups. These data indicate that a normal cardiac silhouette in patients with dilated cardiomyopathy can be explained on the basis of a counterclockwise transverse rotation of the heart within the thorax, and it cannot always rule out the dilatation of the LV.

Adolescent↗
PubMed1992

Prominent negative T waves with QT prolongation indicate reperfusion injury and myocardial stunning.

To observe the clinical course after reperfusion and recovery from myocardial stunning of the left ventricular anterior wall, we prospectively reviewed and analyzed cardiac enzymes, ECG changes, echocardiograms, and cineangiograms in 8 patients with the acute ischemic syndrome who fulfilled the following criteria: 1) no history of previous myocardial infarction, 2) repeated and/or prolonged episodes of chest pain, 3) critical stenosis of the left anterior descending artery with wall motion abnormalities, 4) successful emergency percutaneous transluminal coronary angioplasty, and 5) normal wall motion on repeat cineangiography 4 to 8 weeks later. Creatine kinase (CK) and/or its cardiac isoenzyme (CK-MB) were minimally elevated in all cases. Wall motion was normalized with the reduction of end-systolic volume (end-diastolic volume: from 139 +/- 25 to 140 +/- 37 ml, ns, end-systolic volume: from 68 +/- 16 to 39 +/- 13 ml, p < 0.001, ejection fraction: from 51 +/- 6 to 71 +/- 6%, p < 0.001). Serial echocardiograms showed normalization of wall motion within 4 to 28 days. T wave inversion in the left precordial leads developed 30 min to 5 hours after the cessation of chest pain or successful reperfusion, and prominent negative T waves (1.6 +/- 0.6 mV) with QT prolongation (0.56 +/- 0.08 sec) in V3 or V4 reached their peak values within one to 5 days. ECG abnormalities resolved after 21 to 95 days. These ECG findings may indicate reperfusion injury and the presence of myocardial stunning in the anterior wall of the left ventricle.

Aged↗
PubMed1991

One-step purification of Escherichia coli H(+)-ATPase (F0F1) and its reconstitution into liposomes with neurotransmitter transporters.

About 30% of the protein in the inner membrane of Escherichia coli strain DK8/pBWU13 is H(+)-ATPase (F0F1), and practically homogeneous F0F1 could be obtained by gradient centrifugation after solubilization of these membranes. The recombinant plasmid pBWU13 carries the unc operon for F0F1. When reconstituted into liposomes, F0F1 formed an ATP-dependent proton gradient and membrane potential. Proteoliposomes reconstituted with F0F1 and solubilized transporters from chromaffin granules or synaptic vesicle membranes could transport serotonin, dopamine, and norepinephrine dependent on ATP hydrolysis. F0F1 can be obtained rapidly from DK8/pBWU13, and its reconstitution into liposomes with transporters may be useful for monitoring these transporters during their purification.

Adrenal Medulla↗
PubMed1991

Mutations in Ser174 and the glycine-rich sequence (Gly149, Gly150, and Thr156) in the beta subunit of Escherichia coli H(+)-ATPase.

A sequence motif in the beta subunit of Escherichia coli F1 (Gly-Gly-Ala-Gly-Val-Gly-Lys-Thr, residue 149-156, where conserved residues are underlined) is one of the glycine-rich sequences found in many nucleotide binding proteins. In this study, we constructed a plasmid carrying all the F0F1 genes. This plasmid gave the highest membrane ATPase activity so far reported. Substitution of beta Gly149 by Ser suppressed the effect of the beta Ser174----Phe mutation (defective H(+)-ATPase), but beta Gly150----Ser substitution did not have this effect. A single mutation (beta Gly149----Ser or beta Gly150----Ser) gave active enzyme with altered divalent cation dependency and azide sensitivity: the beta Gly149----Ser mutant enzyme had 100-fold lower azide sensitivity and essentially no Ca(2+)-dependent activity, but had the wild-type level of Mg(2+)-dependent activity with active oxidative phosphorylation. Introduction of a beta Gly149----Ser or beta Gly150----Ser mutation with the beta Ser174----Phe mutation also lowered the Ca(2+)-dependent activity and azide sensitivity. Consistent with our previous findings (Takeyama, M., Ihara, K., Moriyama, Y., Noumi, T., Ida, K., Tomioka, N., Itai, A., Maeda, M., and Futai, M. (1990) J. Biol. Chem. 265, 21279-21284), a beta Thr156----Ala or Cys mutation impaired ATPase activity, suggesting that the hydroxyl moiety at position 156 is essential for the catalytic activity. The possible location of the catalytic site including divalent cation binding site(s) is discussed.

Amino Acid Sequence↗
PubMed1991

Molecular cloning of cDNA encoding the 16 KDa subunit of vacuolar H(+)-ATPase from mouse cerebellum.

cDNA for the 16 kDa subunit of vacuolar H(+)-ATPase was cloned from mouse cerebellum and sequenced. The deduced polypeptide (155 amino acid residues; molecular weight, 15,808) was highly hydrophobic and homologous to the subunits of bovine adrenal medulla, Torpedo marmorata electric lobe, Drosophila and yeast. Glu-139 (supposed to be essential for proton transport) was also conserved as the potential dicyclohexylcarbodiimide binding site. The subunit had four transmembrane segments: Segment II and IV were highly homologous and Glu-139 was located in Segment IV. The roles of the non-conserved regions are discussed.

Adrenal Medulla↗
PubMed1991

[Coronary collateral function evaluated by coronary hemodynamics and myocardial lactate metabolism during rapid atrial pacing].

To elucidate coronary collateral function in the ischemic myocardium, we studied coronary hemodynamics and myocardial lactate metabolism of the collateral-dependent myocardium before and during rapid atrial pacing. Subjects consisted of 38 patients who were categorized into 3 groups according to their coronary and coronary collateral arteriographic findings: 14 patients with normal coronary arteriograms (Group A), 15 with significant stenosis in the left anterior descending coronary artery (LAD) without collaterals (Group B), and 9 with LAD stenosis and collaterals (Group C). Estimates of cross-sectional area (CSA) obtained from the orthogonal coronary arteriograms, and the great cardiac vein flow (GCVF) and myocardial lactate extraction ratio (MLER) before and during rapid atrial pacing were used as parameters to evaluate coronary stenosis. The results were as follows: 1. The cross-sectional areas in Groups B and C were 86% and 91% of that in Group A, respectively. 2. In Group B, there was a good linear relationship between cross-sectional area and % delta GCVF, as shown in % delta GCVF = 2.90 + 36.22 x CSA (r = 0.61, p < 0.05). This relationship was modified in Group C, increasing % delta GCVF against CSA. 3. Myocardial lactate extraction ratio in Groups B and C decreased significantly after rapid atrial pacing, while, it remained unchanged in Group A. This ratio after rapid atrial pacing did not differ significantly between the 2 groups. 4. In 3 of 4 patients with total LAD occlusions, GCVF and anterior coronary resistance before and during rapid atrial pacing were similar to those of Group A.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Pacing, Artificial↗
PubMed1990

Kinetic studies of chromaffin granule H+-ATPase and effects of bafilomycin A1.

Vacuolar type H+-ATPase purified from bovine chromaffin granules did not show simple Michaelis-Menten type kinetics, and had apparent Km values of 5 microM, 30 microM and 300 microM. These three Km values suggested the presence of catalytic cooperativity during steady-state hydrolysis. The single turnover rate was 10(-3)-fold the maximal velocity of the enzyme and similar to the rate estimated from the velocity of steady-state hydrolysis with the smallest Km value (5 microM). The H(+)-ATPase was inhibited by the stoichiometric binding of bafilomycin A1, a specific inhibitor of vacuolar type H(+)-ATPase. This inhibitor not only lowered the rate of ATP hydrolysis at the single catalytic site, but also affected the catalytic cooperativity of the enzyme.

Adenosine Triphosphatases↗
PubMed1990

Peripheral blood CD4-mediated enhancement and CD8-mediated suppression in the presence of recombinant hepatitis B virus core antigen.

The proliferative response of peripheral blood T cells to hepatitis B core antigen (HBcAg) was studied in hepatitis B patients. CD4+ T cells from patients with chronic active hepatitis type B (CAH-B) exhibited a significant proliferative response to HBcAg, especially in hepatitis B envelope antigen (HBeAg)-positive patients. In contrast, there was no apparent T cell reaction to HBcAg in patients with CAH non-A, non-B, HBeAg-positive healthy carriers and in healthy volunteers. The proliferative response to CD4+ cells to bacterial extracts of Escherichia coli was always insignificant in all patients and healthy volunteers. The CD8+ cells did not proliferate in response to HBcAg in any subject, even in the presence of autologous irradiated CD4+ responder cells. The CD8+ cells, preactivated with HBcAg and HBcAg-reactive irradiated autologous CD4+ cells, suppressed the proliferative response to autologous CD4+ cells to HBcAg but not the response to phytohemagglutinin in HBcAg-responder CAH-B patients. CD4-mediated HBcAg-specific enhancement and CD8-mediated HBcAg-specific suppression in the peripheral blood compartments of HBcAg-responsive CAH-B patients are possible.

Adult↗
PubMed1990

[Estimation of left ventricular diastolic characteristics in patients with myocardial ischemia by pulsed Doppler echocardiography: transmitral blood flow velocity in postextrasystolic beats].

To investigate diastolic dynamics of the left ventricle in postextrasystolic (PES) beats during myocardial ischemia induced by rapid atrial pacing (RAP), transmitral blood flow velocity was evaluated using pulsed Doppler echocardiography in 13 subjects. The subjects consisted of eight patients with ischemic heart disease and five healthy subjects. An atrial extrasystole was artificially induced before and immediately after RAP, while the transmitral flow velocity was recorded continuously. The ratio of the early peak diastolic velocity to the peak atrial velocity (A/E) on PES beat was less than that in a basic beat without an extrasystole. The A/E increased in the PES beat in four patients who experienced myocardial ischemia; whereas, other patients and the normals showed a decrease in the A/E in the PES beat even after RAP. These findings indicated that left ventricular dynamics coupled with left atrial contraction are quite different in myocardial ischemic and nonischemic situations, and that postextrasystolic potentiation may be a useful means of detecting the ventricular diastolic dysfunction.

Blood Flow Velocity↗
PubMed1989

Uni-site catalysis by Escherichia coli F1-ATPase with different numbers of bound nucleotides.

We prepared two types of E. coli F1 by slightly different gel filtration procedures of the purified F1: F1(II) contained about 2 mol, and F1(V) about 5 mol of bound adenine nucleotides per mol of the enzyme. Thus F1(II) had more than 2, possibly 3, vacant catalytic sites, while F1(V) had less than one vacant catalytic site. The rate of ATP hydrolysis in uni-site catalysis (in the presence of inorganic phosphate) was about 3-fold higher with F1(II) than with F1(V), suggesting that ADP and inorganic phosphate bound at the catalytic sites of F1(V) changed the kinetics of uni-site catalysis significantly.

Adenine Nucleotides↗
PubMed1989

Prognostic significance of conduction disturbance and reduction of left precordial voltage of electrocardiogram in hypertrophic cardiomyopathy.

To clarify the prognostic significance of electrocardiographic changes in hypertrophic cardiomyopathy, we retrospectively evaluated serial electrocardiograms in 77 patients with hypertrophic cardiomyopathy who were followed for more than 1 year. The electrocardiographic features analyzed were conduction disturbance and left precordial QRS voltage. There were 4 sudden deaths. Various conduction disturbances appeared in 32 (44%) of the remaining 73 patients. Intraventricular conduction delay was the most common (47%). The left precordial voltage decreased in 19 (26%), increased in 3, and did not change in 51. The left ventricular end-diastolic pressure at the initial investigation was significantly higher and clinical deterioration was more frequently seen in patients with a conduction disturbance or reduction of QRS voltage than in those without these electrocardiographic changes. Also, echocardiographic analysis showed that left ventricular dimensions increased significantly (from 4.4 +/- 0.6 to 4.8 +/- 0.7 cm in end-diastole and from 2.6 +/- 0.6 to 3.1 +/- 0.8 cm in end-systole; p less than 0.01, respectively) and left ventricular fractional shortening was reduced (from 41 +/- 8 to 36 +/- 11%; p less than 0.01) in the 32 patients with conduction disturbance during the follow-up period although absolute cavity size remained normal in 26 of these patients. These parameters did not change in those without conduction disturbance. Histopathological analysis of endomyocardial biopsies showed that myocardial fibrosis in the left ventricle was frequently associated with these electrocardiographic changes. However, such changes were not present in the sudden death patients. It is concluded that conduction disturbance and the reduction of QRS voltage are significant parameters which suggest a poor prognosis in patients with hypertrophic cardiomyopathy, but are not predictors of sudden death.

Adolescent↗
PubMed1989

[A case of left atrial ball thrombus observed in a patient with combined valvular heart disease, accompanying anomalous coronary venous run].

A 53-year woman, who had been under observation for combined valvular heart disease, was admitted to our hospital for further examination of embolic episodes to brain and kidney. Echocardiographic examination showed the evidence of free-moving ball thrombus in the left atrium, and emergent cardiac catheterization following the echocardiography confirmed the diagnosis of it as well as mitral stenosis, aortic regurgitation with stenosis, and tricuspid regurgitation. In addition, coronary angiography disclosed the anomalous coronary venous run. With these findings, the cause of embolic episodes was found to be due to the thrombus in the left atrium. In the surgery performed a ball thrombus of 40 x 35 x 36 mm and a mural thrombus of 15 x 35 x 20 mm in size in the left atrium were detected and removed, and both mitral and aortic valves were replaced to artificial ones. She had a good hospital course after the surgery and discharged without any complication. In this report, we discussed a case of left atrial thrombus observed in a combined valvular heart disease, with 29 literatures reported in our country.

Coronary Vessel Anomalies↗