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Biomedical subjects

M Sakakibara

Publications and source records attributed to M Sakakibara.

At least 109 records · Page 6Linked to original sources
PubMed1990

[Influence of aging on coronary arterial morphology, exercise tolerance and daily physical activity in the chronic stage of myocardial infarction].

Coronary angiographic (CAG) findings, exercise tolerance and daily physical activity were studied with reference to aging in 314 cases of the chronic myocardial infarction and in 199 cases of angina pectoris. Exercise tolerance was evaluated by a symptom-limited treadmill test and the daily physical activity by the functional classification of the New York Heart Association (NYHA) based on questionnaires filled out by the patients. Although the single to multivessel disease ratio decreased with age, there was no significant trend in diffuse or segmental character of stenosis with age. In addition, more than 80% of patients showed good exercise tolerance of more than stage II in Bruce's protocol. However, there was a general trend towards decrease in exercise tolerance with age. Furthermore approximately 80% of patients showed a good daily activity. However, the NYHA (I + II) to NYHA (III + IV + cardiac death) ratio was lower in patients aged 60 or more compared to those under age 60. Patients aged 60 or more with single vessel disease had lower daily physical activity compared to the under 60 age group, although this did not seem to be related to any physical limitation. Therefore, social and occupational aspects as well as the clinical severity of ischemic heart disease should be considered in the treatment of elderly cases.

Activities of Daily Living↗
PubMed1990

[A case of primary tracheal adenoid cystic carcinoma performed curative surgical resection].

A 67-year-old woman who was diagnosed as a relative early primary tracheal adenoid cystic carcinoma by preoperative examination underwent surgical resection. The histopathological extension of this carcinoma into the tracheal wall was much greater than was suggested before operation and 6 tracheal rings was curatively resected circumferentially. Median sternotomy and transection of the left brachiocephalic vein facilitated access to the trachea. To resect the extensive segment of the trachea, the right pulmonary ligament and hilum were mobilized. Additionally Dedo's laryngeal release was performed to lessen the tension at the anastomosis. Then the flap of the pleura and adipose tissue with the right internal mammary artery and vein was wrapped around the anastomosis for revascularization and protection of brachiocephalic artery. The postoperative course was not eventful. The postoperative dysphagia by Dedo's laryngeal release was mild and resolved within 7 days after operation. And the postoperative mammary arteriography showed the vessels around the anastomosis. This wrapping procedure is easy and does not need a laparotomy. So we think it is beneficial for prevention against postoperative complications of tracheoplasty.

Aged↗
PubMed1990

Structural studies on aldolase isozymes through protein engineering.

Enzymatic studies on aldolase isozymes have been carried out by techniques of protein engineering. Site-directed mutagenesis helps us to verify the roles of amino acid residues in catalytic reactions. Chimeric fusion proteins give us information about the regions which specify the characteristics of the isozymes. The results are: (1) In aldolase A, COOH terminal Tyr and Lys-107 residues play important roles in catalysis, especially in binding of FDP. (2) Aspartic acid at the 128th residue in aldolase A is essential to thermostability; no other residue such as glutamic acid can substitute for it. (3) Studies on chimeric fusion proteins indicate that the C-terminal region (including C-terminus Tyr) or aldolase A is responsible for its substrate specificity, which is not seen in aldolase B. (4) A region near NH2 terminus in aldolase B determines its specific structure. (5) The region including His-107, Asp-128, and Tyr-137 (B-A junction of BA137) is located in a turn which is exposed outward (a model architecture by Sygusch et al [1987]). In BA137, this region would be constrained, and play a significant role in catalysis, thermostability, etc. (6) Tertiary structure of aldolase B seems to be dissimilar to that of aldolase A.

Amino Acid Sequence↗
PubMed1990

[Two resected cases of pulmonary aspergilloma in acute leukemia].

Remission rate of leukemia has been improved by development of recent antileukemic chemotherapy. But opportunistic infection in secondary immunodeficiency has increased. Especially pulmonary mycoses often occurs and its prognosis is poor. But if patient with leukemia complicates pulmonary mycoses, it should be cured as soon as possible and antileukemic chemotherapy should be continued. We successfully performed surgical treatment for 2 pulmonary aspergillosis, which were complicated in stage of remission induction of acute leukemia.

Adult↗
PubMed1989

Construction and expression of human aldolase A and B expression plasmids in Escherichia coli host.

E. coli expression plasmids for human aldolases A and B (EC 4.1.2.13) have been constructed from the pIN-III expression vector and their cDNAs, and expressed in E. coli strain JM83. Enzymatically active forms of human aldolase have been generated in the cells when transfected with either pHAA47, a human aldolase A expression plasmid, or pHAB 141, a human aldolase B expression plasmid. These enzymes are indistinguishable from authentic enzymes with respect to molecular size, amino acid sequences at the NH2- and COOH-terminal regions, the Km for substrate, fructose 1,6-bisphosphate and the activity ratio of fructose 1,6-bisphosphate/fructose 1-phosphate (FDP/F1P), although net electric charge and the Km for FDP of synthetic aldolase B differed from those for a previously reported human liver aldolase B. In addition, both the expressed aldolases A and B complement the temperature-sensitive phenotype of the aldolase mutant of E. coli h8. These data argue that the expressed aldolases are structurally and functionally similar to the authentic human aldolases, and would provide a system for analysis of the structure-function relationship of human aldolases A and B.

Amino Acid Sequence↗
PubMed1989

The sennoside constituents of rhei rhizoma and sennae folium as inhibitors of serum monoamine oxidase.

Four (in total) compounds with inhibitory effects on the activity of bovine serum monoamine oxidase were isolated from the methanol-water extracts of Rhei Rhizoma (Daiou) and Sennae Folium (Senna), and identified as sennosides A, B, E and F. Among them, sennosides A and B were obtained from both Rhei Rhizoma and Sennae Folium, while sennosides E and F were detected only in the former. The 50% inhibitory concentrations of the four sennosides were 17, 9, 24 and 13 microM, respectively, and the type of inhibition by seenosides A and B with respect to allylamine as the substrate was non-competitive.

Anthraquinones↗
PubMed1989

[A clinical study of pulmonary tissue uptake of cefuzonam and its use in prophylaxis of postoperative infections].

From our study on cefuzonam (CZON), a new antibiotic agent, with regard to pulmonary tissue uptake and use in prophylaxis of postoperative infections in 20 patients undergoing thoracotomy, we were able to reach the following conclusions: 1. Following intravenous infusion over 1 hour of 1 g of CZON immediate preoperatively, the mean serum concentration at 1 hour after commencement of the infusion reached at 41.5 micrograms/ml (serum peak value), then gradually decreased with a half-life in the beta-phase of 1.20 hours. 2. The mean CZON concentration in normal pulmonary tissue at 1 hour after commencement of the infusion was 12.7 micrograms/g with a half-life in the beta-phase of 1.28 hours. Although the number of cases examined was small at only 4, the mean pulmonary tissue level in obstructive pneumonitic lesions was 13.7 micrograms/g, and an average half-life in the beta-phase was 1.65 hours. 3. Mean bronchiolar CZON concentrations at 2, 4, and 6 hours after commencement of the infusion were 14.5, 3.1, and 2.8 micrograms/g, respectively, with a half-life in the beta-phase of 3.53 hours. 4. Among the patients undergone thoracotomy with use of CZON, no postoperative infections occurred nor severe adverse reaction was observed. CZON attained good transfer in the pulmonary tissues, particularly in the bronchiolar tissue, hence it appears useful as a prophylactic against postoperative infections in respiratory disease.

Aged↗
PubMed1988

[Flow imaging of the cardiovascular system using magnetic resonance imaging].

Blood flow images by magnetic resonance imaging (MRI) using a 0.25 T unit were evaluated for nine normal volunteers and 108 subjects with a variety of cardiovascular abnormalities. Using the non-gated short-spin echo (SE) technique, blood flow in the cardiovascular systems was not imaged in the normal volunteers. Using end-systolic and end-diastolic SE techniques for the normal subjects, blood flow in the cardiac chambers was not clearly imaged. Blood flow in the ascending aorta and aotric arch often did not appear in the gated SE images of the normal subjects. However, blood flow in the descending aorta was often observed in the gated SE images. Blood flow imaging was demonstrated by both non-gated and gated SE techniques in regions where blood flow was relatively slow; for example, in the left atrium of mitral stenosis, in an aortic aneurysm, in a false lumen of an aortic dissection, and in the left ventricle having old myocardial infarction. Using the non-gated inversion recovery (IR) technique, no blood flow was imaged in the cardiovascular system except in the left atrium of one case with mitral stenosis. Using the non-gated short SE technique, there was good correlation between the thrombus formation and the presence of blood flow images in the left atria of 17 patients with mitral stenosis, and in the aneurysmal portions of the aorta or in the false lumens of aortic dissection of 18 patients. It was suggested that mural thrombi in such diseases were related to the relatively slow blood flow. Blood flow imaging easily distinguished stagnant blood flow from mural thrombi using non-gated short SE, end-systolic SE, and IR techniques. Thus, blood flow imaging using MRI should become an important means of evaluating the cardiovascular system.

Adult↗
PubMed1988

[Right ventricular function in cardiovascular disease evaluated by magnetic resonance imaging].

The usefulness of ECG-gated magnetic resonance imaging (MRI) in evaluating right ventricular architecture and function was assessed by measuring right ventricular wall thickness, wall motion, and areas of the right ventricular cavities of seven normal subjects and 46 with cardiac disease, including atrial septal defect (ASD: six cases), hypertrophic cardiomyopathy (HCM: 19), dilated cardiomyopathy (DCM: eight), and old myocardial infarction (OMI: 13 cases). A superconductive MRI system was used. Transverse images at the level of the tricuspid valve were obtained for measurements. ECG-gated MRI clearly showed the right ventricular myocardium throughout the cardiac cycles and facilitated measuring wall thickness and cross-sectional areas of the right ventricular cavity in all subjects. In normals the mean value and standard deviation of the anterior wall thickness of the right ventricle and the area index of the right ventricular cavity at end-diastole were 3.4 +/- 0.7 mm and 10.6 +/- 1 cm2/m2, respectively. The anterior and lateral walls and tricuspid annulus moved inward to the right ventricular cavity in systole, and the excursion of the lateral wall and tricuspid annulus was larger than those of the anterior wall. The interventricular septum (IVS), however, moved outward to the left ventricle in systole. The anterior wall thickness of the right ventricle in patients with HCM was 5.8 +/- 1.4 mm thicker than that of normal subjects. In contrast to normals, the area index of the right ventricular cavity was larger in patients with ASD (18.4 +/- 5.4 cm2/m2) and smaller in patients with HCM (9.1 +/- 1.6 cm2/m2). The IVS moved inward in all patients with ASD and in several patients with HCM. The anterior and lateral wall motion was decreased in patients with ASD and DCM.

Adult↗
PubMed1987

Molecular gene mapping of human aldolase A (ALDOA) gene to chromosome 16.

Mapping of human aldolase A (ALDOA) gene was performed by molecular hybridization techniques using a panel of human-mouse cell hybrids and sorted fractions of human metaphase chromosomes besides in situ hybridization. For the purpose, three kinds of DNA probes derived from the coding region (probe-1), the 3' noncoding region (probe-2), and the coding and 3' noncoding regions (probe-3) of human aldolase A cDNA clone, pHAAL116-3, were selectively employed. The results of RNA and DNA blot analyses indicated that the human ALDOA gene is located on chromosome 16. The in situ hybridization experiment also indicated that the ALDOA gene was localized to 16q22-q24.

Animals↗
PubMed1987

Effects of alpha 2-adrenergic agonists and antagonists on photoreceptor membrane currents.

Type B photoreceptors of the nudibranch mollusc Hermissenda crassicornis receive excitatory synaptic potentials (EPSPs) whose frequency is controlled by potential changes of a neighboring cell known as the S optic ganglion cell which is thought to be electrically coupled to the presynaptic source of these EPSPs, the E optic ganglion cell. The frequency of the EPSPs increases when a conditioned stimulus (light) is paired with an unconditioned stimulus (rotation) during acquisition of a Pavlovian conditioned response. The results of the present study are consistent with an adrenergic origin for these EPSPs. Noradrenergic agonists (greater than 100 microM), norepinephrine and clonidine, only slightly depolarize the type B cell but clearly prolong its depolarizing response to light. Serotonin, by contrast, causes hyperpolarization of the type B cell's resting potential as well as after a light step. Clonidine reduces voltage-dependent outward K+ currents (IA, an early current, ICa2+-K+, a late Ca2+-dependent current) that control the type B cell's excitability (and thus its light response and membrane potential). These effects of clonidine are reduced or blocked by the alpha 2-receptor antagonist, yohimbine (0.5 microM), but not the alpha 1-blocker, prazosin. The same yohimbine concentration also blocked depolarizing synaptic excitation of the type B cell in response to depolarization of a simultaneously impaled S optic ganglion cell. Histochemical techniques (both the glyoxylic acid method of de la Torre and Surgeon and the formaldehyde-induced fluorescence or Falck-Hillarp method) demonstrated the presence of a biogenic amine(s) within a single neuron in each optic ganglion as well as three or four cells within the vicinity of previously identified visual interneurons. No serotonergic neurons were found within the optic ganglion or in proximity to visual interneurons. A clonidine-like synaptic effect on type B cells, therefore, could amplify conditioning-specific changes of membrane currents by increasing type B depolarization and possibly, as well, by elevating intracellular second messengers.

Adrenergic alpha-Agonists↗
PubMed1987

[Diagnostic evaluation of ischemic heart disease by X-ray computed tomography and magnetic resonance imaging].

To assess the usefulness of X-ray computed tomography (CT) and magnetic resonance imaging (MRI) in detecting and evaluating ischemic heart disease, conventional and enhanced CT were performed for 180 patients (150 with transmural infarction, 12 with subendocardial infarction, and 18 with angina pectoris). MRI examinations were performed for 38 patients (31 with transmural infarction, three with subendocardial infarction, and four with angina pectoris). With enhanced CT, two findings in the myocardium were direct evidence of myocardial infarction: 1. filling defects on the early scans, and 2. late enhancement of the myocardium on the delayed scans. The former were observed mainly at the sites of recent anterior myocardial infarction and the latter were seen in about half of the patients with recent and remote anterior myocardial infarctions. However, these findings were inadequately imaged in patients with inferoposterior infarction and subendocardial infarction. Among 137 patients with transmural infarction, enhanced CT revealed left ventricular aneurysms in 51 (37%) and ventricular thrombi in 26 (19%). ECG-gated MRI apparatus having a superconducting magnetic operating at 0.25 Tesla was used, and data for this study were collected using the single-slice spin echo technique. In eight of nine patients with acute myocardial infarction, gated MRI demonstrated the infarcted myocardium as regions of high signal intensity relative to that of the adjacent normal myocardium. Such a difference in MRI signal intensity was scarcely recognized in the chronic stage of myocardial infarction, but the indirect findings of infarction, such as regional wall thinning, wall motion disturbances, left ventricular aneurysms, and ventricular thrombi were easily detected using MRI. No characteristic finding was obtained by CT or MRI in patients with angina pectoris.

Aged↗
PubMed1987

[Diagnosis of atrial septal defect using magnetic resonance imaging].

We studied the morphological features of defects of the interatrial septum using magnetic resonance imaging (MRI) to determine the sizes of defects and other abnormalities. MR images were obtained in 28 patients with atrial septal defect, including five cases with complicated anomalies (two with Ebstein's anomaly, one pentalogy of Fallot, and one anomalous pulmonary vein connection and azygos continuation). Images were also obtained in the control subjects including seven normal volunteers and 142 patients with various acquired heart diseases. The diagnosis of atrial septal defect was established by cardiac catheterization, angiography and two-dimensional echocardiography prior to the MRI studies, and in 14 patients, the diagnosis was confirmed by surgery. The MRI unit had a superconducting magnet and operated at 0.25 or 0.50 Tesla. A spin echo pulse sequence was used with an echo time of 40 or 60 msec. At the beginning of this study, non-gated MRI images were obtained in the 28 controls and in three patients with atrial septal defect. Nongated MRI could not image the anatomical structure of the interatrial septa of 12 of the 28 controls, or any of the three patients with atrial septal defect. Nongated MRI was, therefore, inadequate for visualizing cardiac anatomy. Gated MRI images were obtained in 141 controls and in 25 patients with atrial septal defect. Gated MRI revealed the interatrial septum, interventricular septum, atrioventricular septum, mitral valve, tricuspid valve and other intracardiac structures in most subjects. In 17 control subjects (12%), however, there was a very faint signal from the central portion of the interatrial septum. In these instances, there was a gradual fading of the signal of the interatrial septum, so that they could be distinguished from the atrial septal defect. The sudden disappearance of the signal from the interatrial septum was observed by gated MRI in all 25 patients with atrial septal defect. The sizes of the defects by MRI coincided with the findings at surgery in all 14 patients. MRI showed right atrial dilatation, right ventricular hypertrophy and dilatation, and pulmonary artery dilatation in most of the patients having atrial septal defect. Complex anomalies associated with atrial septal defect were also clearly shown by MRI, such as displacement of the tricuspid leaflets in two patients with Ebstein's anomaly, and anomalous pulmonary venous connection and persistent left superior vena cava in one patient. These results indicated that gated MRI is a valuable noninvasive method of diagnosing atrial septal defect and complicating anomalies.

Adolescent↗
PubMed1986

A new restriction endonuclease from Spirulina platensis.

Three restriction endonucleases, Sp1I, Sp1II and Sp1III have been purified partially from Spirulina platensis subspecies siamese and named. Sp1I cleaves bacteriophage lambda DNA at one site, phi X 174 RF DNA at two sites, but does not cleave pBR322 DNA. This enzyme recognizes the sequence 5'CGTACG3' 3'GCATCG5' and cuts the site indicated by the arrows. Sp1II is an isoschizomer of Tth111I and Sp1III is an isoschizomer of HaeIII.

Base Sequence↗
PubMed1986

The role of neurochemical modulation in learning.

Tsukahara creatively exploited the advantages of a "simple system" approach in a vertebrate context to gain cellular insights into the learning process. The molluscs Aplysia and Hermissenda have provided useful invertebrate examples of this approach. For classical conditioning of Hermissenda a temporal sequence of cellular transformations has been found to correspond to and to substantially account for a learning-specific behavioral transformation. For at least days after the conditioning a biophysical record persists: two voltage-dependent K+ currents, IA and ICa2+-K+, remain reduced in amplitude and at least IA shows an increased rate of inactivation. More recently, a similar biophysical record of associative memory has been identified in the mammalian brain (Disterhoft et al., 1986). Other experiments suggest that a synergistic interaction of C-kinase activation with Ca2+/CaM-kinase activation enhances and prolongs Ca2+-mediated K+ current reduction. The effects of alpha-receptor agonists to enhance depolarization of type B cells (a site of visual-vestibular convergence) and in turn acquisition of classical conditioning are in contrast to the effects of serotonin which can hyperpolarize and thereby reduce depolarization during the acquisition process. For both LTP and LTD, application of a neurotransmitter itself is not sufficient to produce long-lasting neural modification. In this respect, both the LTP and LTD models are more similar to the biochemical sequence implicated in Hermissenda conditioning than to the mechanism initiated by serotonin-like substances proposed for Aplysia sensitization.

Animals↗