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Biomedical subjects

Y Harada

Publications and source records attributed to Y Harada.

At least 433 records · Page 24Linked to original sources
PubMed1992

[Total aortic arch replacement through a median approach].

Seven patients underwent total aortic arch replacement only through a median approach since March 1990, in our institute. The woven Dacron graft with three side arm branches were used. After the proximal anastomosis at the ascending aorta, open distal anastomosis at the descending aorta was performed in five cases, under circulatory arrest of the lower body using separate perfusion to the brain. In two cases with true aneurysms involving the aortic arch, occlusion balloon catheters were employed for distal anastomosis. The anastomosis of the arch vessels was performed after coronary reperfusion. There was no early operative death, and our results demonstrate that total arch replacement can be safely accomplished through a median approach with an acceptably low operative risk.

Aged↗
PubMed1992

[Clinico-immunological study of the patients infected with Mycobacterium avium complex (MAC)].

Lymphocyte functions of the peripheral blood in the patients infected with MAC (MAC-pts) were evaluated comparatively with age-matched normal controls by using flow cytometry. The results obtained were as follows: 1) In normal controls, the number of total lymphocytes and the proportion and number of T lymphocyte subsets significantly decreased with age. The proportion of natural killer lymphocytes significantly increased in elder controls. 2) In MAC-pts, the number of total lymphocytes and T lymphocyte subsets were significantly lower and the proportion of natural killer lymphocytes were higher respectively than normal controls. 3) The lymphocyte proliferation induced by PPD-S stimulation in vitro in MAC-pts was significantly lower than the normal controls in both age groups of 50-69 and 70-89 years old. 4) The lymphocyte proliferation induced by PPD-S stimulation in MAC-pts was increased slightly by adding recombinant IL-2 and significantly higher by depletion of monocytes. By combination of both treatments, it recovered to the level of normal controls. From these results, we suggested that the decline of lymphocyte proliferation induced by PPD-S stimulation in MAC-pts was due to the decrease of IL-2 production by antigen committed lymphocytes and suppression by monocytes. 5) Lymphocyte proliferation induced by PHA stimulation in vitro was also significantly depressed in MAC-pts as compared with normal controls.

Adolescent↗
PubMed1992

[Clinical evaluation of 123I-BMIPP myocardial scintigraphy in patients with hypertrophic cardiomyopathy].

123I-BMIPP myocardial scintigraphy was performed in 13 patients with hypertrophic cardiomyopathy and compared with 201Tl myocardial scintigraphy performed within 3 months for evaluating the clinical significance of 123I-BMIPP myocardial scintigraphy. SPECT images were divided into 13 segments and segmental images were visually scored on a 4 (increased tracer uptake) to 0 (severely decreased tracer uptake) scale according to the tracer uptake. In comparison of 123I-BMIPP early images and 201Tl perfusion images, mismatches were seen in about 70% of all segments. The number of segments demonstrating lower myocardial uptake of 123I-BMIPP was larger than that of 201Tl. In hypertrophic regions, the tracer uptake of 123I-BMIPP early images was significantly lower than that of 201Tl images and the lower uptake of 123I-BMIPP delayed images was more marked. In non-hypertrophic regions, no significant difference was seen between the tracer uptakes of 123I-BMIPP early images and 201Tl images but the tracer uptake of 123I-BMIPP delayed images was significantly lower than that of 201Tl images. The mismatch between the tracer uptakes of 123I-BMIPP images and 201Tl images was thought to be a reflection of disordered myocardial fatty acid metabolism. "Washout", the difference between the tracer uptakes of 123I-BMIPP early images and delayed images was also thought to be a reflection of disordered myocardial fatty acid metabolism. These results suggest that 123I-BMIPP is a promising radiopharmaceutical for evaluating disordered myocardial fatty acid metabolism in patients with HCM.

Cardiomyopathy, Hypertrophic↗
PubMed1992

[Diffuse subendocardial ischemia in a patient with aortic valve stenosis without coronary artery disease by exercise 201Tl SPECT].

A case of aortic valve stenosis without coronary artery disease was confirmed to have diffuse subendocardial ischemia by exercise Thallium-201 myocardial single photon emission computed tomography. A 72-year-old woman, who had been diagnosed as aortic valve stenosis, was admitted because of chest pain during exercise. In cardiac catheterization findings, the patient angiographically had normal coronary arteries and no asynergy of left ventricular wall motion. The peak flow velocity in continuous wave Doppler echocardiography was about 5.0 m/sec at aortic valve level, providing a pressure drop of 100 mmHg across a stenotic valve with calculating on a modified Bernoulli equation (PG = 4V2). Thallium-201 myocardial SPECT images during exercise showed a transient "dilation and a widespread wall thinning" of left ventricle with apical perfusion defect. Simultaneous electrocardiogram showed further ST depression and the patient had chest pain. In 6 months after aortic valve replacement the patient no longer demonstrated both apical perfusion defect and "wall thinning" in postoperative thallium-201 myocardial SPECT images and also had neither ST depression nor chest pain. Thus; a transient "dilation and wall thinning" of left ventricle in this patient is suspected to be a sign of diffuse subendocardial ischemia.

Aged↗
PubMed1992

[Long-term patency of aorto-coronary saphenous vein grafts].

One hundred eighty-two cases with 814 aorto-coronary saphenous vein grafts were studied according to coronary risk factors (smoking, hypertension, hyperlipidemia, diabetes mellitus, obesity and family history). The patency rates of all cases were as follows, early-term (within one year after operation): 92.3%, mid-term (within 5 years after operation) 80.7%, long-term (more than 5 years after operation): 66.0%. Coronary risk factors have great influence upon the mid- and long-term patency, especially upon the latter. The long-term patency rate of the grafts complicated with hyperlipidemia was 57.4% and that without hyperlipidemia was 81.8% (p less than 0.01). Hyperlipidemia, complicating 55.5% of all cases, was one of the most influential factors on the patency and also the most difficult one to be controlled. In the United States and Europe, many cases were complicated with hyperlipidemia, and it was considered that the poor patency of the saphenous vein grafts in those countries was due to this fact. Pathological studies revealed that hyperplasia of intima and media, characteristics of venosclerosis, appeared frequently in the saphenous vein grafts having more than three risk factors, and that the factors had effect not only upon arteries but also upon veins. So we conclude that saphenous vein grafts are the materials of good long-term patency, and that the control of the risk factors, particularly hyperlipidemia, is the key to improve the patency.

Adolescent↗
PubMed1992

[Surgical techniques of ventricular assist device].

Since October 1982 to April 1990, we had 16 ventricular assist device (VAD) cases in our institute. Using this VAD system that was produced by Nippon Zeon company, surgical techniques for cannulation and de-cannulation could be made very easily, and connection between cannulae and pump also could be performed quickly. In this article, the actual surgical techniques and the know-how were illustrated in detail. If this techniques can be more accustomed, the clinical results of VAD cases will be improved.

Cardiac Catheterization↗
PubMed1992

[Right-sided patent ductus arteriosus with a right aortic arch and right descending aorta].

We experienced an extremely rare anomaly, i.e. right-sided persistent ductus arteriosus with a right aortic arch and right descending aorta. Reviewing the literature, we found only two cases clinically reported in Japan as far as we know. The diagnosis was established by angiography and MRI. We treated the patient successfully through right thoracotomy.

Aorta, Thoracic↗
PubMed1992

[Ulnar nerve palsy in a RA patient after total knee replacement: a case report].

A 49-year-old housewife had suffered from classical seropositive rheumatoid arthritis for 24 years. The shoulders and hands were involved but the most severs pain and deformity were in both elbows and knees. Consequently, she was unable to sit on wheel chair and was confined to a bed. And then, she was admitted to the Chiba Rehabilitation Center in September, 1986 for bilateral total knee replacement. In April 1987, she had an operation upon the right knee and in June, she had an operation upon the left knee. About 6 weeks after surgery, she felt numbness in bilateral hands. The diagnosis was cubital tunnel syndrome. This was confirmed by electromyographic studies. Surgical release was undertaken without delay. The day following operation the patient remarked on the absence of numbness in bilateral hands.

Arthritis, Rheumatoid↗
PubMed1992

[Surgery versus detachable balloon embolization of pulmonary arteriovenous fistula: clinical experience].

We experienced 4 pulmonary arteriovenous fistula cases 2 of which were treated surgically and 2 were subjected to detachable balloon embolization therapy. Favorable results were obtained in the detachable balloon embolization therapy. In treating pulmonary arteriovenous fistula, if the lesion is in the position where the catheter can be reached easily and is composed of a single afferent-efferent vessel unit, it would be advisable to perform the embolization therapy first, and then to apply an operative procedure preserving lung tissue as much as possible.

Adult↗
PubMed1991

Kinetic behavior of the monodehydroascorbate radical studied by pulse radiolysis.

The reactions of the monodehydroascorbate radical (As.-) with various biological molecules were investigated by pulse radiolysis. As.- reacted with both fully reduced and semiquinone forms of hepatic NADH-cytochrome b5 reductase with second-order rate constants of 4.3 x 10(6) and 3.7 x 10(5) M-1 s-1, respectively, at pH 7.0. In contrast, no reaction of As.- with ferrous cytochrome b5 could be detected by pulse radiolysis, whereas the oxidation of cytochrome b5 by As.- was observed by ascorbate-ascorbate oxidase method. This suggests that the rate constant of As.- with the ferrous cytochrome b5 must be several orders in magnitude smaller than that of the disproportionation of As.-. On the other hand, As.- reduced Fe3+EDTA with a second-order rate constant of 4.0 x 10(6) M-1 s-1 but did not reduce ferric hemoproteins such as metmyoglobin, methemoglobin, and cytochrome b5 by either the pulse radiolysis or the ascorbate-ascorbate oxidase method.

Animals↗
PubMed1991

Suppression of type II collagen-induced arthritis by monoclonal antibodies.

Some mouse monoclonal antibodies raised against chicken type II collagen suppressed or delayed the onset of chicken type II collagen-induced arthritis in DBA/1 mice. This was correlated with the suppression of anti-mouse type II collagen antibody responses following immunization with chicken type II collagen. The epitopes recognized by the suppressive antibodies were found to be present on cyanogen bromide (CB)-digested collagen peptides CB-11 and CB-12. This was also confirmed by the finding that administration of the CB-11 or CB-12 peptide suppressed the induction of arthritis.

Animals↗
PubMed1991

Gene responsible for deficient activity of the beta subunit of C8, the eighth component of complement, is located on mouse chromosome 4.

Sera from 73 strains of mice were tested for hemolytic activity through the classical and the alternative pathways (CP and AP) in a single radial hemolysis assay. Sera from 16 out of 45 laboratory inbred strains had no lytic activity, and Ouchterlony analysis with anti-C5 serum showed them to be C5-deficient. Sera from 2 out of 28 strains derived from wild mice also had no lytic activity, but the C5 molecule was detectable in both. The hemolytic activity of sera from these strains can be restored by the addition of partially purified human C8 or human serum deficient in C8 alpha-gamma, leading us to conclude that strains M.MOL-MSM (MSM) and Mae are deficient in the beta subunit of C8. Typing of (DBA/2J X MSM)F1 hybrids and of progeny of a backcross to MSM showed that this C8 deficiency is controlled by a single recessive gene, designated C8b; the allele with hemolytic activity is C8b1; and the allele with no activity C8b0. Because of synteny homologies in mouse and human, we looked for and found close linkage between C8b and Pgm-2. Typing of recombinant mice for Mup-1 mapped the C8b locus 2.3 centimorgans (cM) telomeric to Pgm-2 on mouse chromosome 4.

Animals↗
PubMed1991

Chemomechanical coupling in actomyosin system: an approach by in vitro movement assay and kinetic analysis of ATP hydrolysis by shortening myofibrils.

On the basis of our recent studies of the sliding distance of actin filaments during one ATP cycle on the surface of myosin-coated glass surface and ATP hydrolysis by rapidly shortening myofibrils, the molecular mechanism of chemomechanical coupling is considered. We conclude that the myosin head can repeat many active cyclic interactions with actins to drive the actin filaments over a long distance during one ATP cycle, and that the distance is variable depending on the load.

Actomyosin↗
PubMed1991

Developmental change in ganglioside expression in primary culture of rat neurons.

Developmental changes in ganglioside levels and patterns were investigated in neuronal cells dissociated from 17-day-old fetal rat hemispheres for up to 7 days of culture. Increases in ganglioside contents and the onset of GM3 synthesis, which is associated with proliferation of glial cells, were observed as the neuronal network was established in cell cultures. The distribution of gangliosides in developing neurons was monitored by the indirect immunofluorescent technique using three anti-ganglioside antibodies. Anti-GM1 antibody showed immunofluorescence only on the cell soma 1 and 3 days after plating and additional binding between cell aggregates by 7 days in culture. GD3 ganglioside, the predominant species in embryonic neurons, was not detected on the neuronal cell surface, whereas the number of positively stained non-neuronal cells was increased at 7 days. Monoclonal A2B5 antibody suggested that polysialogangliosides play a role in neuronal network formation. In 1-day-old culture, however, all antibodies bound poorly to cell surface antigens and strongly to cells, the membranes of which were permeabilized with acetone. These results suggest that a substantial amount of gangliosides are retained, transformed within the cell to more complex gangliosides, and translocated to the cell surface following neurite outgrowth and morphological changes.

Animals↗
PubMed1991

Electrophysiological study on a cochlear outer hair cell.

In order to examine the mechanoelectrical transduction of a cochlear hair cell, the electrical characteristics of the cochlear outer hair cell were studied. Both the cell dissociation technique and the patch clamp technique were used in this experiment. The membrane current gained by the voltage clamp method had a biphasic component, an initial inward current and a following outward current. After blocking the outward current by internal Cs ion and external TEA, the inward current has voltage-dependent inactivation. Also, the membrane potential change was studied by the current clamp method.

Action Potentials↗
PubMed1991

Cochlear fistula found in a naturally healed tympanic cavity.

A cochlear fistula found in a naturally healed mastoid cavity is reported. The patient is a 53-year-old Japanese woman who was complaining of unsteadiness. She had a long history of otorrhoea in childhood. Her tympanic and mastoid cavities were widely open and were covered by thin epithelium. The posterior wall of the ear canal was missing. She had no hearing in the ear but responded to electrical promontory testing. Exploratory surgery was indicated at which fistulae of the basal turn of the cochlea and the horizontal semicircular canal were found. These fistulae were sealed by pieces of bone and muscle.

Cochlea↗
PubMed1991

Autoreactive T-cell clones which suppress cytotoxic T cell responses.

Autoreactive T-cell clones (Thy 1+, CD4+, CD3+) which suppress generation of cytotoxic T lymphocytes (CTL) were established in long-term in vitro culture by stimulation with GM3-liposomes or soluble melanoma (B16) antigen composed of GM3. The T-cell receptors (TCR) of two representative clones analyzed used the same TCR alpha- and V13+ beta-chains. The clones produce only interferon gamma(IFN-gamma) but not interleukins (IL)2 and 4, despite their CD4+ phenotype, suggesting that they are not a typical TH1 or TH2 type. The clones are effectively stimulated by IFN-gamma treated (I-Ab/GM3+) B16 melanoma or I-Ab-transfected GM3+ L cells, but not by GM3-/I-Ab mutant melanoma, EL 4, or I-Ad/k-transfected L cells. This strongly suggested the involvement of GM3/class II in T-cell recognition. Antigen specificity was required for stimulation of the clones. However, once stimulated, they suppressed CTL generation in an antigen non-specific fashion. As class II+ B16 melanoma cells effectively function as antigen-presenting cells to stimulate the autoreactive suppressor T cell (Ts) clones of this type, this negative circuit between class II+ tumor cells and IFN-gamma-producing Ts would be a possible mechanism whereby tumor cells could escape the immune system.

Animals↗