Biomedical subjects

H Takakura

Publications and source records attributed to H Takakura.

At least 37 records · Page 2Linked to original sources

PubMed2000

Influence of cardiopulmonary bypass temperature on circulatory pathophysiology and clinical outcomes.

This study was designed to investigate the effects of cardiopulmonary bypass (CPB) perfusion temperature. Forty-four patients who had undergone elective coronary bypass surgery were randomly divided into 2 groups (22 patients each) according to their perfusion temperature (N group=36 degrees C; L group=30 degrees C). The concentrations of endogenous catecholamines, complements, elastase, serotonin, arachidonic acid metabolites and endothelin underwent various changes throughout the CPB but did not exhibit any statistical differences in either group. None of the substances measured correlated with systemic vascular resistance at any time. The temperature of the perfusion appears to be a major determinant of vascular tone. The postoperative PO2 was better, and postoperative pulmonary vascular resistance lower in the N group (p<0.05), most likely because of a much larger water balance during hypothermic CPB (p<0.01). The postoperative blood loss was statistically less in the N group (p<0.05). Although apparent brain damage, evidenced by the leakage of creatine kinase-BB, was not seen, the jugular bulb venous hemoglobin saturation levels (<50% in 27% of the N group, p<0.05) and higher lactate levels suggested that normothermic perfusion was relatively disadvantageous. It is concluded that normothermic CPB was relatively safe and advantageous with regard to hemostasis and pulmonary function.

Aged↗

PubMed2000

Aortic valve replacement with concomitant annular enlargement for small aortic annulus of less than 19 mm.

Three female patients with aortic stenosis associated with a severely small annulus underwent aortic valve replacement. In intraoperative measurements, a 19-mm obtulator could not pass through the aortic annulus in each case. We therefore concluded that it would be difficult to implant an appropriate-sized prosthesis in a routine fashion, so we performed an annular enlargement in a modified Nicks procedure. By using a wide teardrop-shaped patch for enlargement and slightly tilting insertion of a prosthesis, a 21 mm bileaflet mechanical prosthesis could be inserted into the enlarged annulus. Despite being a simpler method than other enlarging procedures, a two- or three-sizes larger prosthesis than the native annulus can be inserted with relative ease. Thus, the use of a 19 mm mechanical prosthesis may be avoidable in most adult cases.

Aged↗

PubMed2000

[Combined use of ante- and retrograde cardioplegia: limited efficacy in elective coronary artery bypass].

One Hundred and twenty-four patients undergoing elective coronary bypass surgery were retrospectively selected and divided into two groups according to their difference of cardioplegic methods, either antegrade (AC) only (n = 65) or combination of ante- and retrograde (AC + RC) cardioplegic delivery (n = 64). Myocardial blood flow in the right (RV) and left ventricles (LV) was measured during the cardioplegia by a laser Doppler. Peak CPK-MB levels were compared postoperatively between the two groups and more in detail according to extent of coronary obstructive disease. 1) The antegrade administration of cardioplegic solution provided preferential flow to the RV compared to the LV, whereas the retrograde administration resulted in the opposite result (AC; LV 6.9 +/- 4.7, RV: 8.6 +/- 5.3, p < 0.05, RC; LV: 9.0 +/- 4.9, RV: 5.9 +/- 4.6 ml/min/100 g, p < 0.05). This result suggested that the combination of both administrations was meaningful to obtain uniform distribution of cardioplegic solution. 2) The peak CPK-MB, compared in the entire two groups, was slightly low in the combination use (AC; 48 +/- 16, AC + RC; 43 +/- 15 IU/l, p = 0.08), but the clinical meaning did not exist. However, in the severe cases, which involved two of following criteria (left main disease, severe occlusion of left or right coronary), the max CPK-MB level was statistically decreased by the combined use of ante- and retrograde cardioplegia (AC; 50 +/- 16, AC + RC; 40 +/- 12 IU/l, p < 0.05). We concluded that the merit of combined use was limited to the cases with severely extended coronary obstructive disease.

Aged↗

PubMed1999

Identification and specificities of N-terminal acetyltransferases from Saccharomyces cerevisiae.

N-terminal acetylation can occur cotranslationally on the initiator methionine residue or on the penultimate residue if the methionine is cleaved. We investigated the three N-terminal acetyltransferases (NATs), Ard1p/Nat1p, Nat3p and Mak3p. Ard1p and Mak3p are significantly related to each other by amino acid sequence, as is Nat3p, which was uncovered in this study using programming alignment procedures. Mutants deleted in any one of these NAT genes were viable, but some exhibited diminished mating efficiency and reduced growth at 37 degrees C, and on glycerol and NaCl-containing media. The three NATs had the following substrate specificities as determined in vivo by examining acetylation of 14 altered forms of iso-1-cytochrome c and 55 abundant normal proteins in each of the deleted strains: Ard1p/Nat1p, subclasses with Ser-, Ala-, Gly- and Thr-termini; Nat3p, Met-Glu- and Met-Asp- and a subclass of Met-Asn-termini; and Mak3p subclasses with Met-Ile- and Met-Leu-termini. In addition, a special subclass of substrates with Ser-Glu- Phe-, Ala-Glu-Phe- and Gly-Glu-Phe-termini required all three NATs for acetylation.

Acetylation↗

PubMed1999

A 22-year course of the Kay-Shiley disc valve with muscle guard at the mitral position.

Almost 33 years have elapsed since the introduction of the Kay-Shiley disc valve in Japan. Following the development of pyrolite carbon, the Kay-Shiley valve is no longer in clinical use. We report the case of a female patient who had had an isolated mitral valve replacement with the Kay-Shiley disc valve with single muscle guard 22 years previously. After numerous thromboembolic episodes with the Kay-Shiley disc valve, a successful reoperation was done with the CarboMedics valve. The explanted valve revealed that the grooved occluder disc had a loosely adherent clot. The thromboembolism is a notorious complication associated with this valve. We recommend re-replacement of the Kay-Shiley valve whenever possible.

Adult↗

PubMed1999

Strategy for balancing anticoagulation and hemostasis in aortocoronary bypass surgery: blood conservation and graft patency.

The minimal effective dose of aprotinin on hemostasis under normothermic perfusion, the influence of anticoagulant therapy on graft patency, and the thromboembolic and hemorrhagic events were investigated after aortocoronary bypass graft operation (CABG). One hundred CABG patients under normothermic perfusion were randomly divided into the following groups: (1) coumadin plus acetylsalicylic acid (ASA) (n=32); no aprotinin used during cardiopulmonary bypass (CPB); (2) minimal-dose, 10(6) KIU during CPB, aprotinin used, followed by ASA and coumadin (n=36); and (3) very low-dose, total of 2x10(6) KIU before CPB and during CPB; aprotinin used; anticoagulation therapy with heparin early after surgery and followed by replacement with ASA and coumadin (n=32). The patency of arterial grafts was 100% in all groups. The patency of vein grafts was 95-98% and there was no difference among the groups. The blood loss was significantly reduced in both aprotinin groups (groups 2 and 3) compared to the coumadin plus ASA group, although no difference existed between the 2 aprotinin groups. Postoperative thrombotic and hemorrhagic events were not observed in any group. From this study, it was concluded that 10(6) KIU aprotinin in pump-prime-only followed by oral ASA and coumadin was the recommendation from the benefit/cost consideration.

Adult↗

PubMed1999

Real time measurement of heparin concentration during cardiopulmonary bypass.

BACKGROUND: A heparin/protamine titration system for measurement of heparin levels (Hepcon) is promising for efficient anticoagulation during cardiopulmonary bypass (CPB). METHODS: Fifty-seven patients subjected to CPB were divided into two groups, control (n = 24) and Hepcon groups (n = 33). The Hepcon group was further divided into three subgroups according to perfusion temperature. For the control group, conventional administration of an anticoagulant (300 IU/kg of heparin) and reversal protocol (heparin 1: protamine 1) was performed. For the Hepcon group, a heparin dose-response assay directed the initial dose of heparin. Hepcon also determined the dose of protamine by the titration. The initial dose of heparin in the control group (300 IU/kg) was statistically less than that of Hepcon group (360+/-80 IU/kg). RESULTS: In the Hepcon group, the sensitivity to heparin was correlated with coagulation time (r = -0.78) and antithrombin III levels (r = 0.70), and individual difference of sensitivity resulted in a wide range of dosage (160 to 490 IU/kg). A strong correlation was observed between plasma and whole blood concentration of heparin (r = 0.86). However, they did not correlate with ACT values. Perfusion temperature didn't affect the heparin level, but did the ACT value. In the Hepcon group, the dose of protamine was significantly less and adverse events were rare. CONCLUSIONS: In conclusion, whole blood heparin measurements correlated well with plasma heparin concentration. Protamine titration of heparin reduced the dose of protamine and decreased the chance of adverse reactions.

Anticoagulants↗

PubMed1999

Assessment of coronary artery bypass surgery by exercise thallium imaging.

The purpose of this study was to assess the coronary artery bypass grafting (CABG) in exercise thallium-201 scintigraphy. The study was performed on 18 consecutive patients undergoing elective surgery. We compared the results of the scintigraphic examinations, 1 week before and 1 month postoperatively. Of the 47 bypass grafts, 20 (42. 6%) grafts contributed to the improvement of the ischemic areas and 38% of the bypass grafts did not change the scintigraphic patterns after surgery. Some bypass grafts had been performed on the stenotic arteries that dominated the areas which preoperatively showed normal exercise scintigraphic patterns yet were considered to worsen in the near future. Such grafts main contribution may be to protect and to increase the overall myocardial washout ratio for prevention of an enlargement of ischemic areas.

Aged↗

PubMed1998

Application of subtype-specific monoclonal antibodies for rapid detection and identification of influenza A and B viruses.

We established a rapid method for the identification of influenza A and B virus strains: the peroxidase-antiperoxidase (PAP) staining method with two subtype-specific murine monoclonal antibodies, C179 (H1 and H2 specific) and F49 (H3 specific), and an anti-influenza B virus rabbit polyclonal serum. The types and subtypes of 160 strains were examined, and 158 strains were identified to be the same by the hemagglutination-inhibition (HI) test and the PAP method. In contrast to the results by the HI test, two strains were revealed to be a mixture of two subtypes (H1 and H3) by the PAP method, which was confirmed by plaque cloning. We further analyzed clinical specimens by the PAP method by directly inoculating specimens into Madin-Darby canine kidney cells in microplates. After 40 h of incubation, the types and subtypes of viruses in 52 of 152 specimens were clearly identified. Since the reactivities of the two monoclonal antibodies are not influenced by the antigenic drift of influenza virus, the newly developed method should be applicable not only for rapid diagnosis but also for the epidemiological study of influenza.

Animals↗

PubMed1998

Molecular cloning and expression of cynomolgus monkey interleukin-1beta cDNA.

The cynomolgus monkey cDNA encoding interleukin-1beta (IL-1beta) was molecularly cloned by the reverse transcription polymerase chain reaction from a cDNA library of adherent splenocytes stimulated with lipopolysaccharides. The sequence analysis showed that the monkey IL-1beta cDNA encodes a protein of 268 amino acids and displays a high degree (90%) of homology with the human counterpart. Substitution of amino acids resides mainly in the leader sequences of IL-1beta when compared with those of human IL-1beta. This cloned monkey IL-1beta cDNA was used to express in Escherichia coli as a fusion protein with thioredoxin and in insect cells infected with a recombinant baculovirus after molecular modification where monkey IL-1beta signal sequences were placed prior to the mature sequences of IL-1beta for efficient secretion in insect cells. Recombinant monkey IL-1beta expressed in both systems was shown to react with rabbit antihuman IL-1beta antiserum by Western blot analysis and to have the biological activity of IL-1beta in a bioassay.

Amino Acid Sequence↗

PubMed1997

Sequence requirement for trimethylation of yeast cytochrome c.

Lysine 72 (using the vertebrate numbering system) is trimethylated in cytochromes c from fungi and plants but not from higher animals. We have investigated the characteristics of an amino acid sequence required for trimethylation of lysine 72 by examining 21 altered iso-1-cytochromes c from Saccharomyces cerevisiae having single replacements in the region encompassing residues 67 through 77. These results indicated that tyrosine 74 is critical for trimethylation of lysine 72, whereas replacements at other positions did not produce significant diminutions. Various replacements of tyrosine 74 resulted in different levels of inhibition, with the Y74F replacement causing no significant reduction, and the Y74E and Y74K replacements completely or almost completely preventing trimethylation of lysine 72. However, other similarly spaced lysine and tyrosine residues at other sites in the protein did not result in trimethylation of the lysine residue. Thus, a properly situated aromatic residue, determined by the overall conformation of apocytochrome c in the vicinity of lysine 72, appears to be essential for trimethylation.

Amino Acid Sequence↗

PubMed1997

Molecular cloning of caprine IL-6 cDNA and its expression in insect cells.

To analyze the interactions among immunoneuroendocrinological systems in a miniature Shiba goat, we attempted to clone and express caprine cDNA-encoding interleukin-6 (IL-6) which is well-known to exert a variety of effects on neuroendocrinological functions in small experimental animals. The cDNA-encoding caprine IL-6 was molecularly cloned from a lipopolysaccharide-stimulated adherent splenocyte library by the reverse transcription-polymerase chain reaction. The sequence analysis shows that the cloned caprine IL-6 cDNA encodes a precursor protein of 208 amino acids that is processed to mature protein of 180 amino acids with a predicted molecular weight of 20,524. The amino acid sequence of caprine IL-6 displays 97.8 and 51.1% degree of homology with ovine and human equivalents, respectively. A recombinant baculovirus containing the caprine IL-6 cDNA was shown to induce insect cells to efficiently secrete caprine IL-6 into culture supernatant up to 10(5) U/ml, as confirmed by Western blot analysis and bioassay with an IL-6-dependent cell line.

Amino Acid Sequence↗

PubMed1997

[Successful aortic root replacement with pulmonary autograft (Ross) in two cases of congenital aortic stenosis].

Two cases of 7 and 23 year of age with congenital aortic stenosis associated with the small valve annulus underwent successful aortic root replacement with pulmonary autograft (Ross procedure). Preoperative pressure gradient and the valve size were 120 and 80 mmHg, and 16 and 18 mm, respectively. Even with the small native aortic annulus, pulmonary autografts could be implanted to aortic annulus without autograft distortion by the method of total aortic replacement. The right ventricular outflow reconstruction was performed with PTFE-valved bovine pericardial conduit with securing the posterior muscular edge by a strip of autologous aortic wall. Postoperative course in both patients was uneventful without any rhythm disturbances. During the 12 and 14 months of follow-up, both patients were in excellent clinical condition with no evidence of autograft valve regurgitation and functional deterioration of valved conduit. This procedure was thought to be a preferable method of young cases with congenital aortic stenosis.

Adult↗

PubMed1995

[Relationships between differentiation characteristics of internal membrane systems and contractile properties in chicken pectoralis muscle].

Relationships between differentiation characteristics of internal membrane systems (transverse (T) tubules, sarcoplasmic reticulum (SR) and T-SR junctions (triad)) and contractile properties were investigated in developing (1 to 30 days after hatching) chicken pectoralis muscle. Internal membrane systems were visualized using calcium potassium- ferricyanide and lipid soluble fluorescent dye (DiIC16(3)) and observed by electron and confocal microscopes. Location of triads at the Z-line in pectoralis muscles differentiated in three steps: an initial location of longitudinally oriented triads at the A-I junction (15 days after hatching); a subsequent movement to the Z-line to keep the longitudinal orientation (20 days after hatching); finally rotation to a transverse direction on the Z-line and finishing the differentiation (30 days after hatching). Maximum shortening velocity (+60%) and maximum tension development (+100%) increased following 30 days development after hatching. However, the time courses of the increases in contraction speed and tension development were different. It is likely that the developing pectoralis muscle transiety expresses a protein responsible for adhesion of the triads to the myofibrils at the A-I junction region, and later substitutes that for a Z-line level protein. These separate stages in the differentiation of the E-C coupling units imply distinct cellular mechanisms underlying each of these events as well as their differential regulation during myogenesis in chicken skeletal muscle.

Animals↗

PubMed1994

The influence of age and depth of dentin on bonding.

OBJECTIVES: The purpose of this study was to investigate what influence the two variables of dentin depth and age may have on the tensile bond strengths of three bonding systems. METHODS: Dentin discs prepared from human molars were divided into young and old, superficial and deep surfaces. Three bonding systems, Scotchbond Multi-purpose (3M Dental Products), Superbond D-liner (Sun Medical Co.), and Liner Bond II (Kuraray Co.) were the materials tested for tensile bond strength. In addition, the structural variation of the resin-impregnated, or hybrid, layer was compared among the two variables and three bonding systems. RESULTS: Tensile bond strengths exceeding 10 MPa were obtained for all materials. After ANOVA, an effect on tensile bond strength could be attributed to dentin age or depth for only Superbond D-liner used on deep-young dentin as compared with old-superficial dentin. All other group comparisons failed to show any variation between dentin depth or age. However, specimens bonded to deeper dentin showed slightly lower strengths. SEM observations showed thicker resin-impregnated layers for Scotchbond MP and Superbond D-liner compared with Liner Bond II. Liner Bond II exhibited a thinner and more diffuse resin-impregnated layer, believed to be due to the different dentin conditioning method. SIGNIFICANCE: Dentin age or depth may not show as great an influence on bond strengths with the newer type of bonding systems. The resin-impregnated layer quality, rather than thickness, is believed to be the most important factor for obtaining high tensile bond strengths.

Age Factors↗

PubMed1994

[A case of quadricuspid aortic valve associated with mitral insufficiency].

We report a case of a 70-year-old woman who had congenital quadricuspid aortic valve. She had undergone Manouguian's operation because of the narrow annulus associated with aortic steno-insufficiency and mitral insufficiency. The aortic valve was found to have 4 equal-sized cusps. The noncoronary cusp was divided into two equal parts. This congenital quadricuspid valve was extremely rare anomaly and we have nerve seen the case which had been corrected surgically by Manouguian's procedure. The aortic valve was replaced by a 23 mm St. Jude Medical prosthesis and the mitral valve was replaced by a 29 mm CarboMedics prosthesis. The postoperative course was uneventful and she is doing well six months after operation.

Aged↗

PubMed1994

[Successful treatment by Konno's operation for congenital aortic stenosis associated with hypoplastic valve ring].

A 47-year-old woman with congenital aortic stenosis associated with hypoplastic aortic valve ring underwent aortic valve replacement by Konno method. We have to be careful preventing residual VSD because the left ventricular muscle was weak in the aged with congenital aortic stenosis. In early postoperative period, we also have to do a careful treatment in case by Konno's operation, particularly in the patient of advanced age. However, she made a satisfactory recovery with adequate size of aortic valve replacement.

Aortic Valve↗

PubMed1994

[Autologous fibrin glue from concentrated platelet rich plasma: intraoperative plasma sequestration using autotransfusion device].

Making autologous fibrin glue from intraoperatively collected concentrated platelet rich plasma (C-PRP) was attempted in 5 patients who underwent elective coronary artery bypass. The autologous blood was withdrawn from the patient before cardiopulmonary bypass and sequestrated for C-PRP, concentrated red cells (CRC) and platelet poor plasma (PPP) using an Electromedics Elmd-500 autotransfusion device. CRC and PPP were returned intravenously to the patient as needed intraoperatively or postoperatively. Aprotinin was dissolved in C-PRP to yield a concentration of 1000U/ml to the aim of suppressing the plasmin activity. In another syringe, thrombin was dissolved in 2% calcium chloride solution to 1000U/ml. The C-PRP/aprotinin was mixed in ratios of 20:1, 10:1, 5:1, 3:1 to the thrombin/C a++ solution and observed the time for clotting. The 10:1 and 5:1 mixture usually clotted within 3-5 seconds, whereas it was necessary 5 or more seconds in other ratios. Therefore we used in the ratio of 5:1 for all patients. The fibrin glue from this technique is little different from the fibrin glue on the market in its viscosity, and has some major advantages 1. large amount of glue is available 2. simple and inexpensive 3. eliminate the risk of side effect such as virus transmission.

Blood Platelets↗