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Biomedical subjects

Y Kito

Publications and source records attributed to Y Kito.

At least 73 records · Page 4Linked to original sources
PubMed1992

[Initial and follow-up results of PTCA and PTMC].

On the bases of the initial and follow-up results of patients who underwent percutaneous transluminal coronary angioplasty (PTCA) and percutaneous transvenous mitral commissurotomy (PTMC), the proper applications of these interventional therapies were discussed. The efficacy of PTMC on valvotomy was comparable to open mitral commissurotomy and the procedural safety was noticed. Our results supported the use of PTMC for patients with plicable mitral valve. Despite the good and acceptable results of elective PTCA, low initial success rate and high incidence of major cardiac events including mortality was noted in the group of urgent PTCA for patients with multivessel lesions. The urgent use of PTCA for refractory unstable angina should be restricted to selected patients without high-risk multivessel lesions.

Angioplasty, Balloon, Coronary↗
PubMed1992

[Long-term follow-up of exercise tolerance after coronary bypass grafting].

Six hundred forty-eight serial graded exercise tests were performed on 400 patients up to 10 years after coronary bypass graftings (CABG). The maximal attained exercise tolerance, over 10 METS, were observed in 60% of patients and the negative response to exercise test in 43% of patients. The positive response in various parameters were observed at the following rates: graft occlusion-30% vs graft patent-46% (p less than 0.01); incomplete revascularization-39% vs complete revascularization-22% (p less than 0.01); and less than or equal to 8 METS 4-45% vs greater than or equal to 10 METS-28% (p less than 0.01), respectively. However, no significant difference was observed among number of vessels diseased, number of graftings, and presence of old myocardial infarction. The maximal attained stage of exercise, over 10 METS, in various parameters were at the following rates: less than or equal to 59 years old-70% vs greater than or equal to 60 years old-44% (p less than 0.01); male-63% vs female-32% (p less than 0.01); and graft patent-63% vs graft occlusion-50% (p less than 0.05), respectively. The serial analysis of exercise test demonstrated that improved exercise tolerance appears to persist for at least 5 years after CABG. However, the patients in complete revascularization had a tendency to increase the rate of positive response. In conclusion, the completeness of revascularization as well as graft patency was the main factor limiting exercise tolerance, and correlates with the extent and the duration of improvement after CABG.

Coronary Artery Bypass↗
PubMed1991

Conformation changes of cuttlefish (Euprymna morsei) rhodopsin following photoconversion.

Cuttlefish (Euprymna morsei) rhodopsin solubilized in lauryl ester of sucrose and its photoproduct, acid metarhodopsin, were examined by small-angle X-ray scattering and chromatofocusing to investigate the conformation changes of visual pigment following photoconversion. From spectroscopic studies, it was found that more than 93% of Euprymna rhodopsin could be converted to meta form under the condition of red light irradiation at neutral pH. Since almost pure acid metarhodopsin solution was prepared without changing the specimen concentration, the small-angle X-ray scattering intensities of both pigment-detergent complexes were directly compared. The radius of gyration increased on going from rhodopsin to acid metarhodopsin by approximately 1.5%. There were also discernible changes in the secondary peak intensities. The distribution function, derived by the Fourier transformation of intensity data, showed a significant change around 55 A. The maximum linear dimension of the rhodopsin-detergent complex was about 95 A and hardly changed after illumination. Intensity at zero angle did not change after illumination, suggesting that the aggregation did not occur. The change of the intensity profile could be due to the conformational change of the pigment-detergent monomers. The pI value of rhodopsin determined by chromatofocusing was 5.32 and that of acid metarhodopsin was 5.06, indicating that a few carboxyl groups are newly dissociated. The shift of the protein mass and the charge redistribution were observed following photoconversion.

Animals↗
PubMed1991

Light-induced, GTP-binding protein mediated membrane currents of Xenopus oocytes injected with rhodopsin of cephalopods.

Xenopus oocytes that were injected with rhabdomeric membranes of squid and octopus photoreceptors acquired light sensitivity. The injected oocytes showed a light-induced current having characteristics similar to other G-protein-mediated Cl- currents induced by the activation of other membrane receptors. Pretreatment of the oocytes with pertussis toxin before the injection suppressed the generation of the light-induced current, indicating an ability of cephalopod rhodopsin to cross-react with an endogenous G-protein of Xenopus oocytes.

Animals↗
PubMed1991

Effects of volatile anesthetics on bacteriorhodopsin in purple membrane, Halobacterium halobium cells and reconstituted vesicles.

In this study, we have investigated effects of volatile anesthetics on absorption spectra, proton pumping activity and decay of photointermediate M of bacteriorhodopsin (bR) in differently aggregated states. Anesthetics used in this study are ether-type general anesthetics; enflurane and sevoflurane. The observed effects on bR depend not only on variety or concentration of anesthetics but also strongly on the aggregation state of bR molecules in the membrane. In purple membrane (PM), bR having maximum light absorption at 567 nm (bR567) is formed in the presence of sevoflurane or a small amount of enflurane, while a species absorbing maximally at 480 nm (bR480) is formed upon the addition of large amounts of enflurane. X-ray diffraction studies show that the former species maintains crystallinity of PM, but the latter does not. In reconstituted vesicles where bR molecules exist as monomer, even sevoflurane forms bR480. Flash photolysis experiments show that bR567 contains a shorter-lived M intermediate absorbing maximally at 412 nm in the photoreaction cycle than bR does and that bR480 contains at least two long-lived M intermediates which seem to absorb maximally near and at lower than 380 nm. The measurements of light-induced pH changes of the whole cells and of the reconstituted vesicles in the presence of the anesthetics indicate that bR567 has a enhanced proton pumping efficiency, while bR480 has a quite low or no activity. No significant difference was observed in the anesthetic action between two inversely pumping vesicles. These observations suggest that on the formation of bR480, anesthetics enter into the membrane and affect the protein-lipid interaction.

Anesthetics↗
PubMed1991

Recurrent epicardial fibrosarcoma which arose 12 years after the first resection.

Primary malignant tumours of the heart are very rare, with an incidence of only 0.0017%-0.03% in consecutive autopsy series. Fibrosarcoma of the heart is also rare, representing only about 0.3% of all cardiac tumours. We observed a case of epicardial fibrosarcoma which developed 12 years after the first resection of an epicardial tumour. A 31-year-old woman was referred to our hospital because of fatigue, nausea and right back pain. She had had surgery to resect an epicardial tumour when she was 19 years old. On admission, there was a huge, heterogeneous tumour on the right inferior side of the heart. At surgery, the tumour was totally resected and a pathological diagnosis of fibrosarcoma was made. The patient was free of symptoms for 6 months, but died of a recurrence 11 months after the operation. It is postulated that the epicardial tumour had only been partially resected and had been latent for a rather long period but began to grow rapidly 12 years after the initial resection.

Adult↗
PubMed1991

Percutaneous transluminal coronary angioplasty and coronary artery bypass surgery--early and follow-up clinical results.

To evaluate the efficacies of percutaneous transluminal angioplasty (PTCA) and coronary artery bypass grafting (CABG) for angina pectoris, early and follow-up data were reviewed in 495 patients who had undergone these procedures from 1986 to 1988. In 173 patients with single vessel disease, there were no significant differences in initial success rate and early and late incidences of major complications or cardiac death between 152 patients with elective PTCA and 21 with urgent. When compared in 161 patients with multivessel disease, however, significant differences in success rate were found between 130 patients in the elective PTCA group and 31 in whom PTCA was urgent (81.6% vs. 64.5%, p less than 0.05). Significant differences were also found in early incidence of major complications (3.1% vs. 12.9%, p less than 0.01), early mortality (1.5% vs. 9.7%, p less than 0.01), and the late incidence of cardiac events (6.2% vs. 25.0%, p less than 0.01). These results show that freedom from cardiac death and overall cardiac events in the elective PTCA group as significantly better than that in the urgent group at 42 months of follow-up. Comparing early and follow-up results, on the other hand, there was no statistically significant difference between the elective and urgent CABG groups. Thus, there appear to be limitations on the urgent use of PTCA for refractory unstable angina caused by multivessel disease, and urgent CABG was recommended to high-risk patients of urgent PTCA.

Adult↗
PubMed1991

[Medical therapy in patients with left main coronary artery stenosis].

To elucidate the long-term prognosis of medically-treated patients with left main coronary artery (LMCA) lesions, 119 consecutive patients with LMCA lesions undergoing coronary angiography were analyzed retrospectively. Among these, 3 patients died soon after angiography and were excluded from this study. Among the remaining 116 patients, 22 were treated medically (Group M) for the following reasons: profound left ventricular (LV) dysfunction (3 patients), effective pharmacological treatment (10), and patients' refusal of surgical therapy (9). Among 94 patients who underwent coronary artery bypass graft (CABG), 83 patients survived (Group S). During the follow-up period, cardiac events occurred in 5 patients in Group M; cardiac deaths in 3, non-fatal myocardial infarction (MI) in one and late application of CABG in one. Two-year cardiac event-free rate after diagnosis was 77%, which remained unchanged thereafter. The cumulative survival rate was 83%. The incidence of cardiac events in Group M was higher than that in Group S (p < 0.01). However, cardiac event rates were similar between these 2 groups for patients with good collateral circulations to the left coronary arteries, no preceding MI and LV end-diastolic pressure less than 15 mmHg. We concluded that the Japanese patients with severe LMCA lesions who respond favorably to pharmacological intervention have unexpectedly good prognoses, however, obstructed collateral circulation to the left coronary system, the presence of preceding MI and high LV end-diastolic pressure were all high-risk factors for medically-treated patients.

Adult↗
PubMed1991

[Long-term follow-up results on Bentall's and our modified procedure].

Replacement of the ascending aorta and the aortic valve with composite graft, including reimplantation of coronary ostia, were performed in 84 patients from October, 1978 to December, 1989. Annuloaortic ectasia was the most common indication for surgery (76 patients). Thirty patients (36%) had the Marfan syndrome. Thirty-five patients were performed with original Bentall's procedure. Thirty patients were carried out with our modified technique like Inberg's, the coronary arteries were excised with attachment of the selected piece of the aortic wall, and implanted to the tube prosthesis with continuous suture. Nineteen patients were operated with modified technique by Cabrol or other interposition graft method. The actuarial free of death related to the operation of 4 years was 83%, 88%, and 74% (p = NS) in each methods respectively. The complications of anastomosis, for example, leakage and dilatation of coronary ostia were not seen in our modified Bentall's procedure. In conclusion, our modified method is proved to be reliable and competent.

Adult↗
PubMed1991

[Invasive treatment in patients with prior coronary artery bypass grafting].

In eight hundred eighty three patients with prior coronary bypass grafting (CABG), cardiac symptoms were recurred in 179 patients in late follow-up period (mean 5 +/- 2.8 years). Of 179 patients, 43 patients had PTCA eventually. In these, 57 times of angioplasties were attempted. Twenty-one lesions in venous bypass grafts and 50 in native coronary arteries were performed, respectively. The initial success rate per bypass graft and per stenosis of native coronary artery were 68% and 74%, respectively. Five patients had elective CABG following failed PTCA. There were no emergency CABG procedures required after unsuccessful PTCA. Intracoronary thrombolysis (ICT) were performed in 13 patients. In these, 15 ICT attempts were made. Nine lesions in venous bypass grafts, 9 for native coronary arteries, and 3 for both were attempted. The primary success rate per occlusion was 67%. Twenty reoperation were done. There was one hospital death and one late death due to congestive heart failure 4 years after the reoperation. In conclusion, invasive treatments in patients with prior CABG can be performed with satisfactory safety and good results. Therefore, invasive treatment should be considered in the patients with CABG if cardiac symptoms are disabling and angiographically suitable lesions are present in the native coronary arteries or vein grafts.

Aged↗
PubMed1991

[Influences of intra-aortic balloon pumping on peripheral hemodynamics].

The influences of intra-aortic balloon pumping (IABP) on peripheral dynamics were assessed by Doppler echocardiography. The subjects were 20 patients requiring IABP support, postoperatively, to control low cardiac output state. The flow velocity integral in systole (Int S) and that in diastole (Int D) were measured from left common carotid, superior mesenteric, and terminal aortic flow pattern, and the sum of Int S and Int D (Int S + Int D) was calculated with and without balloon pumping. 1) IABP increased cardiac output significantly (p less than 0.01). 2) Common carotid flow: IABP increased Int S significantly (p less than 0.01), but neither Int S nor Int S + Int D changed significantly with IABP. 3) Superior mesenteric flow: IABP increased Int D significantly (p less than 0.01), but both Int S and Int S + Int D remained unchanged with IABP. 4) Terminal aortic flow: None of Int S, Int D and Int S + Int D changed significantly with IABP. These results suggest that the carotid area can receive much of the increase in cardiac output in systole with IABP, and that the superior mesenteric area can receive much of the volume of blood displaced in the aorta by balloon inflation in diastole.

Aged↗
PubMed1990

[Effects of intra-aortic balloon pumping on mitral flow dynamics after aortocoronary bypass surgery].

Improvement in left ventricular function following intra-aortic balloon pumping (IABP) in 15 patients (aged 51 to 86 years) after coronary artery bypass grafting was evaluated. Using transesophageal atrial echocardiography, the mitral flow velocity integrals in the rapid filling phase (IntR) and in the contraction phase (IntA) were measured from transmitral flow patterns, and the sum of IntR and IntA (IntR + IntA), and the ratios of IntA to IntR (IntA/IntR) were calculated for ON and OFF states of balloon pumping (IABP OFF test). The same parameters were determined during 1:2 assist balloon pumping (IABP 1:2 test); the cardiac cycle with balloon assist was defined as "ON", and that without balloon assist as "OFF". 1. IABP OFF test: IABP increased IntR from 6.4 +/- 1.6 cm to 7.6 +/- 1.9 cm (p less than 0.01), suggesting that a decreased afterload improves left ventricular relaxation. IntA did not change with balloon assist (ON 3.5 +/- 1.2 cm, OFF 3.7 +/- 1.2 cm). IntR + IntA increased from 10.0 +/- 2.0 cm to 11.1 +/- 2.4 cm during IABP (p less than 0.01). IABP reduced the IntA/IntR from 0.62 +/- 0.25 to 0.50 +/- 0.20 (p less than 0.01). The increment in the IntA/IntR without IABP suggests that impaired diastolic filling of the left ventricle due to an increased afterload may be compensated for by enhanced left atrial contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[A case report of coronary artery fistula into the left ventricle].

Communication of the right coronary artery with the left ventricle is considerably rare. We report a case of congenital fistula of the left ventricle. Closure of the fistula was successfully done by Symbas' modification. Thirty cases with coronary artery fistula to the left ventricle reported in Japanese literatures, including our case were reviewed in regard to its surgical treatment.

Adult↗
PubMed1990

[Late results of coronary bypass grafting in patients with concomitant multifocal arteriosclerotic vascular diseases].

Late results of coronary bypass graftings (CABG) in the patients with multifocal arteriosclerotic vascular diseases were reviewed. Between September 1978 and July 1989, 819 consecutive patients underwent CABG. There were 693 males and 126 females, mean ages 58 +/- 8.5 years. Of 819 consecutive patients underwent CABG, 95 patients had the coexistence of multifocal atherosclerosis (Group A). Seventy two patients had aortoiliac or femoropopliteal disease, and 29 patients had aortic aneurysm. The remaining 724 patients had no coexistence of multifocal atherosclerosis (Group B). The mean follow-up periods was 4.0 +/- 2.1 years, and the follow-up ratio was 99.4%. The 5- and 10-year survival rates were 80% and 52% in group A, and 92% and 82% in Group B, respectively. The 5- and 10-year free ratio from cardiac events were 79% and 42% in Group A, and 85% and 61% in Group B, respectively. The 5- and 10-year free ratio from noncardiac events were 53% and 38% in Group A, and 85% and 76% in Group B, respectively. The results showed that the coexistence of multifocal atherosclerotic vascular disease in patients underwent CABG significantly increase the ratio of noncardiac and cardiac events, and decreased life expectancy.

Aged↗
PubMed1990

[A successfully operated case of tetralogy of Fallot with marked left ventricular dysfunction in adult].

Adults, especially high-aged patients with tetralogy of Fallot (TOF) are said to have a higher operative risk than younger ones because of fragility of their myocardium, bleeding from rich collateral circulation to lungs, and other complications such as brain abscess and endocarditis. It is often difficult to determine the surgical risk for total correction in cases of high-aged patients who have such complications. We report a successfully operated high-aged case of TOF with marked left ventricular dysfunction. A 52-year-old male was referred to our hospital because of exertional dyspnea and cyanosis. He had a history of cerebral embolism and meningitis several months prior to admission. On admission, he was NYHA class 3, and cyanosis and clubbed fingers were present. Cardiac catheterization showed a large VSD, 50% over-riding of the aorta and an infundibular pulmonary stenosis. Right to left shunt was 60% and Qp/Qs was 0.38. The left ventricular end diastolic volume index was 109 ml/m2, slightly larger than normal, and the ejection fraction was only 30%. This left ventricular dysfunction was thought to be caused by fibrosis of the myocardium due to longstanding hypoxemia and hypoxemia itself. There is no previous case report dealing with a successful total correction for a high-aged patient with TOF associated with such a severe left ventricular dysfunction. Congestive heart failure in the post-operative period was successfully treated by catecholamine for two weeks. Postoperative cardiac catheterization showed a small left-to-right shunt, and an improvement of left ventricular ejection fraction from 30% to 38%.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1990

[Influences of intra-aortic balloon pumping on superior mesenteric flow dynamics].

The influences of intra-aortic balloon pumping (IABP) on arterial flow of the superior mesenteric artery were assessed by Doppler echocardiography. The subjects were 13 patients postoperatively, requiring IABP support to control low cardiac output state, in which distal aspects of balloons were distal to the superior mesenteric artery. Superior mesenteric flow velocity integral in systole (IntS) and that in diastole (IntD) were measured from superior mesenteric flow pattern, and the sum of IntS and IntD (IntS + IntD) was calculated ON and OFF balloon pumping (IABP ON-OFF test). The same parameters were obtained with balloon inflating on every other beat (IABP 1:2 test); the cardic cycle with balloon assist was defined as "1:2 ON", and that without balloon assist was defined as "1:2 OFF". 1) IABP ON-OFF test. IABP increased IntS from 7.07 +/- 2.56 cm to 9.20 +/- 3.19 cm (p less than 0.05), IntD from 3.00 +/- 1.18 cm to 3.62 +/- 1.40 cm (p less than 0.05), and IntS + IntD from 10.07 +/- 3.48 cm to 12.82 +/- 4.04 cm. Cardiac output increased from 3.89 +/- 1.34 l/min to 4.24 +/- 1.64 l/min with IABP support. The increments in IntS, IntD and IntS + IntD with IABP are attributed, to a large extent, to an increase in cardiac output. 2) IABP 1:2 test. Without balloon inflation, IntS increased (1:2 ON; 7.16 +/- 2.91 cm, 1:2 OFF; 8.41 +/- 3.30 cm, p less than 0.05), and IntD decreased (1:2 ON; 3.51 +/- 1.60 cm, 1:2 OFF; 2.33 +/- 1.25 cm, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗