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Biomedical subjects

K Asano

Publications and source records attributed to K Asano.

At least 397 records · Page 22Linked to original sources
PubMed1987

The effect of cardiopulmonary bypass on T cells and their subpopulations.

To investigate the effect of cardiopulmonary bypass (CPB) on T cells, lymphocyte subsets of peripheral blood and lymphoid organs were monitored during and after open-heart surgery (Group 1). As a control, lymphocyte subsets of peripheral blood were measured in patients undergoing thoracovascular operations without CPB (Group 2). In Group 1, analysis of each subset-to-total lymphocyte ratio revealed that observed lymphocytopenia in the early postoperative days was mainly the result of T cell reduction, and that the decrease of helper/inducer T cells contributed to this decrease. In contrast, no significant fluctuation of any lymphocyte subpopulation ratio was observed in Group 2. Analysis of lymphocyte subpopulation ratios in lymphoid organs showed that reciprocal changes of T cells and their subsets were observed in the bone marrow, thus indicating that the redistribution of T cells (especially of helper/inducer cells) seems to occur between peripheral blood and bone marrow in Group 1. Furthermore, there was no relationship between serum cortisol levels and the changes in lymphocyte subset ratios in Group 1 patients.

B-Lymphocytes↗
PubMed1987

Importance of the mitral complex in left ventricular contraction--an analysis of the results of mitral valve replacement with preservation of the posterior mitral complex.

The importance of the mitral complex in left ventricular contraction was studied in seventy-five patients who underwent mitral valve replacement (MVR) with preservation of the posterior mitral complex (modified MVR:mMVR), and in one hundred and twenty-two patients who had conventional mitral valve replacement (cMVR). Mechanical heart valves (Medtronic Hall or St. Jude Medical valves) were used in MVR. Patients after mMVR showed lower left atrial pressures, higher left ventricular stroke work indexes, and better left ventricular function curve using less catecholamines than those after cMVR during the initial 24 hours following cardiopulmonary bypass. M-mode echocardiographic analysis revealed that the sequential apex-to-base contraction of the ventricular wall was better preserved after mMVR than after cMVR. This tendency was more prominent in mitral regurgitation (MR) than in mitral stenosis (MS) patients. Echocardiographic analysis revealed that the posterior mid left ventricular segment began to contract and reached maximal contraction earlier than the basal segment in patients before and after mMVR. After cMVR, this tendency was less noticeable, and the contraction processed and peaked almost simultaneously in all segments. The mitral complex plays an important role in left ventricular contraction, and modified MVR can be said to be an excellent procedure for preserving left ventricular function.

Cardiopulmonary Bypass↗
PubMed1987

Techniques of modified mitral valve replacement with preservation of the posterior leaflet and chordae tendineae.

Modified mitral valve replacement (MVR) was performed mostly with mechanical valves in 117 patients consisting of 53 patients with mitral regurgitation (MR) and 64 patients with mitral stenosis (MS) or combined mitral valve disease (MSR). Concomitantly, aortic valve replacement (AVR) was carried out in 42 patients, tricuspid annuloplasty (TAP) in 26, tricuspid valve replacement (TVR) in 2 and other procedures in 4. There were 3 hospital deaths and 3 late deaths. In this series, 4 types of technique were utilized in order to preserve the posterior leaflet and chordae tendineae. The authors recommend the following techniques. In pure or predominant MS, after removal of the anterior leaflet and chordae, buttress sutures are placed from the valvular annulus to the posterior leaflet near its free margin. In pure or predominant MR, excising part of the posterior leaflet is added prior to the above-described technique. By using these two techniques, modified MVR can be performed for any type of valve lesion and with any kind of prosthetic valve.

Adolescent↗
PubMed1987

Mechanism of antianaphylactic action of beta-agonists in allergic inflammation of air pouch type in rats.

Using an experimental model of allergic inflammation of air pouch type in rats, the mechanism of antiallergic action of beta-agonists was examined. In this model an immediate increase in vascular permeability and histamine level in the pouch fluid was observed after injecting the antigen (azobenzene arsonate-conjugated acetyl bovine serum albumin) solution into the preformed air pouch on the back of the sensitized rats. The same type of reaction was inducible by injecting anti-rat IgE into the preformed air pouch, but not IgG2a. This fact indicates that the immediate increase in vascular permeability and histamine level is an IgE-mediated anaphylactic reaction. When beta-agonists such as isoproterenol, procaterol and salbutamol were injected into the air pouch together with the antigen, the anaphylactic increase in vascular permeability was suppressed dose-dependently without concomitant decrease in histamine level in the pouch fluid. In contrast, disodium cromoglycate, an inhibitor of degranulation of mast cells, the anaphylactic vascular permeability increase was suppressed in parallel with a decrease of the histamine level. Propranolol, a beta-antagonist, counteracted the effect of beta-agonists. Serotonin-induced vascular permeability was also suppressed dose-dependently by treatment with beta-agonists. Furthermore, vascular permeability in the postanaphylactic phase of the present experimental model was also suppressed by isoproterenol. These results indicate that beta-agonists exert their antiallergic effect by inhibiting the reactivity of local vasculature to chemical mediators released from mast cells.

Adrenergic beta-Antagonists↗
PubMed1987

Postinflammatory mitral and aortic valve prolapse: a clinical and pathological study.

In this study we reevaluated whether the sole cause of mitral valve prolapse (MVP) and aortic valve prolapse (AVP) is myxomatous degeneration. Forty-two surgical cases of prolapsed valves with mitral and/or aortic regurgitation were reviewed (AVP in nine, MVP in 27, and combined AVP and MVP [CVP] in six). On microscopic examination, myxomatous degeneration was observed in 20 patients, including six with AVP, 13 with MVP, and one with CVP. In the other 22 patients, including three with AVP, 14 with MVP, and five with CVP, microscopic examination revealed fibrosis with vascularization and scattered infiltration of inflammatory round cells caused by postinflammatory changes with or without chronic inflammation. We coined the term "postinflammatory valve prolapse" (PIVP) to describe these valves. Both postinflammatory and myxomatous degeneration were observed in seven patients with floppy mitral valves attributable to PIVP. Rupture of chordae tendineae was present in six patients with myxomatous mitral valve and three with PIVP. Seven patients with PIVP had a history of rheumatic fever. The results suggest that valvular prolapse is produced not only by myxomatous degeneration but also by postinflammatory changes, including those caused by rheumatic fever.

Adult↗
PubMed1987

Surgical consideration of replacement of the ascending aorta and aortic valve with a composite valve graft--operative and long-term results of Bentall and DeBono procedure.

Our experience with the Bentall and DeBono procedure is reviewed. Between April, 1977 and April, 1985, seventeen patients underwent repair of annulo-aortic ectasia (9 cases), and dissecting aneurysm with aortic regurgitation (8 cases). Three patients had cardiac tamponade due to rupture of dissecting aneurysm. In regard to this procedure, we recently performed the continuous suture method on the prosthetic valve ring, coronary ostia, and distal anastomosis sites. In this study, there was one early death due to a sudden rupture of the dissecting aneurysm of the left thoracic cavity on the 10th postoperative day. In addition, there were two late deaths due to sepsis and suspected arrhythmia. The late follow-up period ranged from 6 months to 8 years (mean 35 months), and all patients were in NYHA Class I or II. We conclude that the composite valve graft method is an excellent technique for annuloaortic ectasia and ascending aortic dissections with aortic regurgitation because of its low operative mortality and fair survival rate.

Adult↗
PubMed1987

K-259-2, a new inhibitor of Ca2+ and calmodulin-dependent cyclic nucleotide phosphodiesterase from Micromonospora olivasterospora.

K-259-2, a new inhibitor of Ca2+ and calmodulin-dependent cyclic nucleotide phosphodiesterase, was isolated from the cultured broth of Micromonospora olivasterospora K-259. K-259-2 has an anthraquinone moiety in its structure. IC50 values for the effect of K-259-2 against Ca2+ and calmodulin-stimulated activity of the enzyme preparations from bovine brain and heart were 6.6 and 2.9 microM, respectively. On the other hand, basal activity (the activity in the presence of ethylene bis(oxyethylenenitrilo)tetraacetic acid (EGTA) instead of Ca2+/calmodulin) of the bovine brain enzyme, calmodulin-independent cyclic nucleotide phosphodiesterase from bovine heart, and protein kinase C from rat brain were inhibited by K-259-2 to a lesser extent with IC50 values of 27.4, 40.7 and 45.8 microM, respectively.

Anthraquinones↗
PubMed1987

[Hormonal changes during continuous exercise in athletic women].

Recently, the number of women who participate in strenuous exercise has increased significantly. The relationship between delayed menarche and early onset of sports training, and increased incidence of menstrual dysfunction related to athletic activity had led to increased interest. Five basketball players who are among the best players in Japan were subjected to an investigation of endocrinological responses effected by 60 minutes continuous exercise cycle ergometer. The VO2max value was previously examined. Then, the level of load during exercise was established at 60% VO2max in this study. The serum level of estradiol increased significantly in the luteal phase but not so significantly in the follicular phase. Progesterone did not show a significant change during exercise. FSH increased slightly in both phases. However, LH showed a slight increase in the follicular phase and a slight decrease in the luteal phase. On the other hand, prolactin showed a continuous significant increase during exercise in both phases. These data suggested that strenuous daily training leads to a frequent significant increase in prolactin in athletic women and this frequent increase in prolactin may be one of the major factors causing menstrual dysfunction in athletic women. The specialized physician should be more concerned about the managing of athletes who are suffering from menstrual dysfunction.

Adult↗