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Biomedical subjects

H Nishida

Publications and source records attributed to H Nishida.

At least 217 records · Page 12Linked to original sources
PubMed1995

Evidence for immunologic immaturity of cord blood T cells. Cord blood T cells are susceptible to tolerance induction to in vitro stimulation with a superantigen.

T cell blasts resulting from stimulating human cord blood (CB) mononuclear cells (MC) and adult peripheral blood (APB) MC with a bacterial superantigen, toxic shock syndrome toxin-1 (TSST-1), and then with human rIL-2 were investigated for their reactions to restimulation with TSST-1. Expression of TCR V beta 2, which determines the potential reactivity to TSST-1 and of CD45RO, was increased in both TSST-1-induced CB and APB T cell blasts. Most preparations of the TSST-1-induced CB T cell blasts exhibited low or no production of IL-2 and IL-4 in response to restimulation with TSST-1, while the APB T cell blasts showed high responses. TSST-1-induced T cell blasts derived from APB T cells depleted of both CD45RO+ T cells and HLA class II+ T cells showed high IL-2 production in response to restimulation with TSST-1. TSST-1-induced CB T cell blasts generated in the presence of DR+ L cells with high accessory cell activity still showed a low response to restimulation with TSST-1. These results indicate that CB T cells are inherently highly susceptible to tolerance induction by bacterial superantigens, suggesting the immunologic immaturity of CB T cells.

Adult↗
PubMed1995

Inhibitory effect of Mg2+ on the protonophoric activity of palmitic acid.

To discriminate whether fatty acids are uncouplers that cause acceleration of State-4 respiration, associated with a decrease in the protonmotive force, or decouplers that increase respiration without associated decrease in the protonmotive force, we examined the effect of palmitate on functions of rat-liver mitochondria under various conditions. We found that palmitate itself increases State-4 respiration, releases oligomycin-inhibited State-3 respiration, inhibits ATP synthesis and ATP<->Pi exchange reaction, and increases H+ permeability in mitochondrial and model bilayer phospholipid membranes. Thus, palmitate is a classical uncoupler of oxidative phosphorylation. However, these effects were inhibited by Mg2+, due to rapid formation of a stable complex between palmitate and Mg2+.

Animals↗
PubMed1995

Specific arrangement of three amino acid residues for flavin-binding barrel structures in NADH-cytochrome b5 reductase and the other flavin-dependent reductases.

The structure of NADH-cytochrome b5 reductase from pig liver microsomes has been refined to a crystallographic R factor of 0.223 at 2.4 A resolution. A structural comparison between the flavin-binding beta barrel domain of NADH-cytochrome b5 reductase and those of the other flavin-dependent reductases, ferredoxin-NADP+ reductase, phthalate dioxygenase reductase and nitrate reductase, indicated that the overall barrel foldings are similar to each other and that the specific arrangement of three amino acid residues (Arg, Tyr and Ser/Thr) is usually necessary for flavin-binding. These conserved residues overlap each other in their three-dimensional structures and stabilize the flavin-binding site in the four flavin-dependent reductases.

Amino Acid Sequence↗
PubMed1995

Crystal structure of NADH-cytochrome b5 reductase from pig liver at 2.4 A resolution.

The three-dimensional structure of NADH-cytochrome b5 reductase from pig liver microsomes has been determined at 2.4 A resolution by X-ray crystallography. The molecular structure reveals two domains, the FAD binding domain and the NADH domain. A large cleft lies between these two domains and contains the binding site for the FAD prosthetic group. The backbone structure of the FAD binding domain has a great similarity to that of ferredoxin-NADP+ reductase [Karplus, P. A., Daniels, M. J., & Herriott, J. R. (1991) Science 251, 60-65], in spite of the relatively low sequence homology (about 15%) between the two enzymes. On the other hand, the structure of the NADH domain has several structural differences from that of the NADP+ domain of ferredoxin-NADP+ reductase. The size of the cleft between the two domains is larger in NADH-cytochrome b5 reductase than in ferredoxin-NADP+ reductase, which may be responsible for the observed difference in the nucleotide accessibility in the two enzymes.

Animals↗
PubMed1995

Long-term results of aortic valve translocation for mycotic periannular abscess: comparative study of Danielson's original method and our threadless method.

Between June, 1983, and October, 1992, we performed Danielson's original translocation method in four patients (group I) and our translocation method in seven patients (group II), for the treatment of active periannular abscess. There were no perioperative or hospital deaths in either group. The long-term results of these two groups are compared in this report. There were four late deaths (mortality rate 100%) in group I, and three late deaths (mortality rate 43%) in group II. The causes of death were cardiac in six patients and noncardiac in one patient. Vein graft failure occurred in one group I patient (25%) and in two group II patients (28%). Rupture or aortic pseudoaneurysm formation occurred in three group I patients (75%). These findings suggest that our threadless method may be superior to Danielson's original translocation method. Therefore, with close observation, especially of saphenons vein great (SVG) failure, arterial graft use could be acceptable for translocation.

Abscess↗
PubMed1995

Long-term results of coronary artery bypass grafting in elderly Japanese patients.

BACKGROUND: This study was undertaken to examine long-term results of coronary artery bypass grafting in elderly Japanese patients. METHODS: Of 1,425 coronary artery bypass grafting patients over the last 13 years, 137 patients were 70 or more years old and 1,288 were less than 70 years old. Mean number of distal anastomoses was similar in both groups. Postoperative survival and event-free proportion were estimated by the Kaplan-Meier actuarial method and compared among the groups by Cox-Mantel statistical analysis. RESULTS: Operative mortality and the incidence of late cardiac death after coronary artery bypass grafting were equivalent between the elderly and younger groups, although the rates of left main trunk disease, acute myocardial infarction, and emergency operation in the elderly group were significantly higher than those in the younger group. Coronary artery bypass grafting in elderly patients had a relatively high hospital mortality and more late noncardiac deaths, but the incidence of postoperative cardiac intervention in elderly patients was lower than that in younger patients. CONCLUSIONS: These results suggest that coronary artery bypass grafting for elderly patients is encouraged as well as is that for younger patients in a representative Japanese population.

Actuarial Analysis↗
PubMed1995

Post-stenting enlarging false aneurysm of a saphenous vein graft.

Stenting seems to be a definitive procedure after failed balloon coronary angioplasty. This report describes a case of redo coronary bypass grafting and concomitant resection of enlarging false aneurysm of a saphenous vein graft that developed secondary to stenting for recurrent stenosis after serial percutaneous transluminal coronary angioplasty. It warns us of a pitfall in catheter intervention in an aged saphenous vein graft.

Aneurysm, False↗
PubMed1995

Effects of fatty acids and fatty acyl CoA esters on Cu(2+)-induced conversion of xanthine dehydrogenase to oxidase in rabbit liver.

Effects of various fatty acids and fatty acyl CoA esters on Cu(2+)-induced conversion of xanthine dehydrogenase to oxidase in rabbit liver were examined. Cu2+ (2-10 microM) brought about the conversion of xanthine dehydrogenase to oxidase in a dose-dependent manner. Oleic, arachidonic, eicosapentaenoic, and docosahexaenoic acids (50-200 microM) prevented the conversion of xanthine dehydrogenase to oxidase catalyzed by 6 microM-Cu2+. The effect of these four fatty acids was concentration-dependent, whereas palmitic, stearic, and linoleic acids had no effect on the conversion of xanthine dehydrogenase to oxidase at the same concentration range. On the other hand, palmitoyl, linoleoyl, and arachidonoyl CoAs elicited the inhibition of 6 microM-Cu(2+)-induced conversion of xanthine dehydrogenase to oxidase at concentrations of 50, 100, and 200 microM. These results suggest that oleic, arachidonic, eicosapentaenoic and docosahexaenoic acids, and fatty acyl CoAs have the potential to inhibit the conversion of xanthine dehydrogenase to oxidase in rabbit liver.

Acyl Coenzyme A↗
PubMed1995

Effects of fatty acyl coenzyme A esters on lipoxygenase and cyclooxygenase metabolism of arachidonic acid in rabbit platelets.

The effects of fatty acyl coenzyme A (CoA) esters (palmitoyl-, stearoyl-, oleoyl-, linoleoyl- and arachidonoyl--CoA) on the activities of lipoxygenase and cyclooxygenase in rabbit platelets were examined. Palmitoyl-, stearoyl-, oleoyl- and linoleoyl- CoA were potent inhibitors of platelet lipoxygenase activity. In addition to the lipoxygenase, the four fatty acyl-CoA esters elicited inhibitory activity on platelet cyclooxygenase, although the inhibition was a little weaker. The CoA derivative of the icosanoid precursor arachidonic acid (AA) showed little inhibition on lipoxygenase and cyclooxygenase. Palmitic, stearic and oleic acids had little or no effect on lipoxygenase and cyclooxygenase, in contrast with their CoA derivatives. Linoleic acid was more potent than linoleoyl-CoA as an inhibitor of the cyclooxygenase, but it was a weak inhibitor of the lipoxygenase. These results suggest that the CoA derivatives of palmitic, stearic, oleic and linoleic acids have the potential to modulate both platelet lipoxygenase and cyclooxygenase activities and may have functional effects within platelets.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1995

Flow study of surgical coronary artery fistula as an alternative to sequential bypass.

Surgical coronary artery fistula, in which the last anastomosis is created to a low-pressure cardiac chamber, was recently introduced as an alternative method to improve graft flow and patency in a sequential graft when coronary arteries are small or diffusely diseased. To assess graft flow, effect on haemodynamics, flow distribution and to determine proper size of the distal anastomosis, a saphenous vein was sequentially anastomosed from the ascending aorta to the left anterior descending artery and then to the left atrium in eight mongrel dogs. Graft flow was measured before and after opening the fistula to the left atrium between the ascending aorta and left anterior descending artery (flow A) and between the left anterior descending artery and left atrium (flow B). Left atrium pressure and systolic left ventricular pressure (mmHg) were recorded. The diameter of the distal anastomosis was regulated with a bulldog clamp. When distal anastomosis was at 2.5-3 mm mean(s.d.) flow A increased from 64.5(19.5) to 134.7(28.5) ml/min (P < 0.01) without significant left atrial pressure or left ventricular pressure change. With a distal anastomosis of 4 mm or more, flow A increased from 69.8(19.9) to 396.1(62.2) ml/min (P < 0.001). Left atrial pressure increased from 5.6(1.0) to 6.1(0.9) mmHg (P < 0.05) without a change in left ventricular pressure. In both sizes of distal anastomosis, flow to the left anterior descending artery did not change either before or after the shunt (flow B) was opened. Neither volume loading, rapid atrial pacing, neosynephrine or epinephrine infusions caused deleterious haemodynamic effects with the shunt open.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗
PubMed1995

A common group I intron between a plant parasitic fungus and its host.

The self-splicing RNAs known as group I introns exist in many organisms, but their distribution is difficult to explain. We hypothesize that group I introns have been transferred between a parasite and its host. We describe here the discovery of a common group I intron sequence between a plant-parasitic fungus, Protomyces inouyei, and its host, Youngia japonica. It strongly supports our theory that the group I intron had been transferred from the host plant to the parasitic fungus in the course of evolution.

Ascomycota↗
PubMed1995

Tc-99m tetrofosmin. A new diagnostic tracer for parathyroid imaging.

A 42-year old woman with hyperparathyroidism had a CT scan that was suggestive of a small nodular lesion in the left lower neck. Tc-99m sestamibi and Tc-99m tetrofosmin parathyroid imaging were performed 10 minutes and 2 hours after tracer injection. Early imaging with Tc-99m sestamibi demonstrated thyroid and focal uptake in the left lower neck. On delayed imaging, findings suggested a parathyroid adenoma. Imaging with Tc-99m tetrofosmin demonstrated similar findings. The abnormal parathyroid gland was an adenoma.

Adenoma↗
PubMed1995

Abnormal cardiac histology in severe intrauterine growth retardation infants.

Four infants with severe intrauterine growth retardation (IUGR) weighing less than 1000 g at birth developed heart failure and died in our unit, where heart failure of IUGR infants is the main reason of death in extremely low birth-weight infants. The causes of their heart failure are one of the main themes in current neonatal medicine. The subjects of this study were four small for gestational age infants; all died due to heart failure 5 to 10 days after birth. Microscopic specimens of hearts from autopsies were evaluated with respect to the following characteristics: thickness of myocardial fibers, maturation of nuclei, presence of dysgenesis or necrosis in myocardium, and amount of glycogen in the heart. Neither dysgenesis nor infarction of the heart was found but hypoplasia in myocardial fibers and decreased glycogen levels were observed. Maturation delay in myocytes' nuclei did not appear to be severe. We conclude that these infants' hearts failed to adapt to postnatal hemodynamic changes because of inadequate myocardial function and inadequate glycogen reserves.

Fetal Growth Retardation↗
PubMed1995

Oxygenator with built-in hemoconcentrator: a new concept.

A hemoconcentrator is an instrument essential for open heart surgery without blood transfusion. In order to simplify the extracorporeal blood circuit and to facilitate handling of cardiopulmonary bypass, we have combined a hollow fiber unit for gas exchange and that for hemofiltration into one component and developed a new membrane oxygenator with the function of a hemoconcentrator. The cylindrical device consists of a hollow fiber for hemofiltration with another fiber for gas exchange provided outside. Both of them adopt the blood outside perfusion system. Blood enters and flows through the central hole for hemofiltration and then flows into the oxygenator. By applying the flow mode to the device, blood is allowed to flow from the center of the core toward the hollow fiber around it. Therefore, even distribution of blood flow to the entire fiber is realized, and the performance of the device is improved. The oxygen transfer rate was 317 ml/min at a flow rate of 6 L/min, and the ultrafiltration rate was 7 L/h at a flow rate of 4 L/min with a hematocrit of 25%. The combined structure of the two units has not caused any adverse effects. In conclusion, by combining an oxygenator and a hemoconcentrator, excellent and simplified hemoconcentration is made available as the blood outside flow mode is adopted, which is one of the unique aspects of this device.

Equipment Design↗
PubMed1995

Development of an autoflow cruise control system for a centrifugal pump.

To improve the ease of driving a centrifugal pump that is afterload dependent, we have developed an automatic flow control system for the Terumo Capiox centrifugal pump system. This system consists of an autoflow cruise control system with a safety cutoff. The Capiox Pump Console 3000 was controlled by a personal computer through a serial communication line. In the usual manual mode, the motor speed knob works as a pump speed control, and in the autoflow mode, the same knob works as a blood flow rate control. After selecting and obtaining the desired flow rate, the mode was changed from manual to autoflow mode. In the autoflow mode, the computer compares the desired flow rate with the actual flow measured by an ultrasonic Doppler flowmeter and adjusts the motor rotational speed accordingly. During both in vivo and in vitro testing, this autoflow mode was able to return the changed flow that was disrupted by either clamping and declamping of the tubing or by the bolus injection of a vasomotor drug to the selected flow rate within 10 s without any significant fluctuation. In conclusion, the newly developed computer controlled autoflow system was able to produce a reliable and effective flow regulation for a centrifugal pump.

Animals↗
PubMed1995

Current strategy for severe heart failure with mechanical circulatory support.

In the last 10 years, 37 patients received assisted circulation or a ventricular assist device after open-heart operations at the Heart Institute of Japan. After cardiovascular surgery, 12 patients underwent venoarterial bypass (VAB), 13 had biventricular bypass (BVB), 8 had left ventricular bypass (LVB), and the remaining 4 received a left ventricular assist device (LVAD). Weaning and discharge rates of the patients by type of circulatory supports were 41.7 and 25.0% with VAB, 69.3 and 46.2% with BVB, 87.5 and 37.5% with LVB, 75.0 and 50.0% with LVAD, and 44.4 and 11.1% with PCPS, respectively. Concerning complications of postcardiotomy circulatory support, hemorrhage and ventricular arrhythmia postcardiotomy circulatory support, hemorrhage, and ventricular arrhythmia (immature weaning) decreased with low-heparinized isolated left ventricular supports (i.e., LVB, LVAD). However, profound biventricular failure, infection, and multiple organ failure remain as possible complications with any type of assisted circulation. These results suggest that early application of circulatory support and appropriate selection of the mode of support and devices used are important for successful circulatory support.

Adult↗
PubMed1995

The usefulness of serial C-reactive protein measurement in managing neonatal infection.

Recent advances in laboratory technology have enabled us to measure C-reactive protein with a higher sensitivity in a short period using a minimal amount of blood. Thus C-reactive protein can be measured easily several times a day. In this study, serial changes in C-reactive protein values were evaluated in 108 term and 240 preterm newborn infants with suspicion of infection, and the changing patterns of C-reactive protein values were compared with clinical outcome. For a diagnosis of infection, the negative predictive values in term and preterm infants were 99.0% and 97.8%, respectively, although the sensitivities were 61.5% and 75.0%, respectively. Antibiotic therapy was started at birth and discontinued when the changing pattern of C-reactive protein and clinical findings did not suggest infection. As a result, mean durations of administration of antibiotics in the term and preterm infants were 3 and 4 days, respectively. Recognition of the changing pattern of C-reactive protein was very useful in excluding infection and minimizing unnecessary antibiotic therapy in managing neonatal infection.

Anti-Bacterial Agents↗