Biomedical subjects

M Nishiwaki

Publications and source records attributed to M Nishiwaki.

At least 19 recordsLinked to original sources

PubMed1992

Evidence for conversion of human salivary alpha-amylase family A to family B by an enzyme action.

SDS-PAGE showed that human salivary alpha-amylase family A (HSA-A) was converted to family B (HSA-B) in human saliva. This conversion did not occur in the supernatant of saliva which had been centrifuged at 105,000 x g for 60 min. An enzyme which catalyzed the conversion existed in the insoluble fraction of human saliva. The enzyme was solubilized with nonionic or zwitterionic detergents, and showed the maximum activity around pH 6. It was stable between pH 4 and 10, and at a temperature lower than 40 degrees C. The enzyme reduced the molecular weight of HSA-A (62,000) to the same molecular weight (58,000) as that of HSA-B without forming any intermediate. It also changed the PAGE pattern of multiple forms of HSA-A to the same pattern as that of HSA-B. It was not inhibited by protease inhibitors, and it did not destroy the reactivity of HSA-A with anti-human salivary alpha-amylase antiserum. The enzyme diminished the reactivity of HSA-A with concanavalin A. These results indicate that HSA-A was converted to HSA-B through the release of sugar chains by the action of the enzyme in the insoluble fraction of human saliva.

Catalysis↗

PubMed1992

Severe hypoxia due to ventilation-perfusion mismatch caused by aortic arch aneurysm.

We report a very rare case of hugh aortic arch aneurysm associated with aortic restenosis, which caused severe hypoxia due to ventilation-perfusion mismatch by compression of the left main bronchus and the right pulmonary artery. Aortic arch replacement was performed under circulatory arrest and deep hypothermia in addition to aortic valve replacement as a redo operation, and consequently such hypoxia was relieved.

Adult↗

PubMed1992

[Efficacy of nicorandil on myocardial protection during coronary artery bypass grafting--a comparison with diltiazem].

Diltiazem (DTZ), a calcium slow channel blocker, is estimated to be highly effective for myocardial protection and the prevention of perioperative coronary spasms (PCS). However, the use of high doses of DTZ sometimes results in difficulty in coming off cardiopulmonary bypass due to negative chronotropic activity. Nicorandil (NCD) has remarkable coronary vasodilating effect but possesses little negative chronotropic activity. The purpose of this study was to compare NCD with DTZ with respect to effect on myocardial protection during coronary artery bypass grafting (CABG). As parameters, excess lactate (delta XL), redox potential (delta Eh), left and right ventricular stroke work indices (LVSWI, RVSWI), cardiac index (C.I.), systemic vascular resistance index (SVRI.), myocardial isoenzymes (CK-MB, LDH1), number of PCS and recovery time of chronotropic action were used. delta XL, delta Eh, LVSWI, RVSWI, C.I., SVRI, CK-MB, LDH1 were measured at 0, 1, 3, 6, 9, 18 and 24 hours after the removal of aortic cross clamping. The degree of chronotropic action was evaluated by the length of the recovery time to self beat or normal sinus rhythm after the removal of aortic cross clamping. Forty patients who underwent CABG with retrograde cold blood cardioplegia between Dec. 1989 and May 1991 were divided into the NCD group (n = 20), in which 1.1 micrograms/kg/min NCD was continuously administered from the beginning of the operation and the DTZ group (n = 20), in which the initial St. Thomas cardioplegia containing 5 mg/L and subsequent cold blood cardioplegia solution contained DTZ 3.5 mg/L, for a total DTZ dose of less than 10 mg.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardioplegic Solutions↗

PubMed1992

[Ischemic cardiomyopathy associated with ischemic mitral regurgitation--a case report of successful repair].

We experienced a case of 62-year-old man with ischemic cardiomyopathy and mitral regurgitation. He had a heart failure of New York Heart Association class IV together with unstable angina. His further examination showed an enlarged left ventricle with markedly reduced ejection fraction (12.9%) and ischemic mitral regurgitation of grade III associated with 3-vessel disease. He underwent three coronary artery bypass graftings and mitral annuloplasty by a modification of Kay's method. He showed a remarkable improvement of heart failure and cardiac function together with a disappearance of mitral regurgitation. He discharged from hospital in NYHA class II on the 50th postoperative day and lives an almost normal life now. Operative indication and management of ischemic cardiomyopathy and mitral regurgitation were discussed.

Coronary Artery Bypass↗

PubMed1992

[Surgical treatment of primary cardiac tumors].

Twenty patients with primary cardiac tumors were operated on during the past ten years. The age of 15 female and 5 male patients ranged from 17 to 73 years. Eighteen patients had myxomas, 16 of which located in the left atrium and 2 in the right atrium. Systemic embolism occurred in 8 patients, subsequently caused cerebral infarction in 4, ischemia of extremities in 2, myocardial infarction in 1 and pulmonary infarction in 1. Emergency operation was performed in 5 patients because of severe congestive heart failure. In all cases, removal of myxoma was performed together with the excision of the wall to which the pedicle attached with the use of cardiopulmonary bypass. One patient with pulmonary infarction underwent resection of the infarcted lung simultaneously. Only one patient with severe heart failure died of pulmonary insufficiency one month after the operation. Another patient with cerebral infarction underwent clipping of cerebral aneurysm which appeared later in the infarcted area. The 17 patients including the latter patient showed a good recovery and no local recurrence during the follow-up period of 1 to 120 months. Two patients had malignant tumors, which were malignant fibrous histiocytoma of the left atrium and leiomyosarcoma of the pulmonary artery, respectively. Both of these rare tumors were resected noncuratively and led to the death because of their local recurrence with distant metastasis, though they received adjuvant chemotherapy. The symptoms, complications, diagnoses, surgical treatment and outcome of the primary cardiac tumors are reviewed in this study.

Adolescent↗

PubMed1992

[Coronary artery bypass surgery in patients with severely impaired left ventricular function].

The efficacy and problem of coronary artery bypass grafting (CABG) in patients with severely impaired left ventricular function (left ventricular ejection fraction < or = 30%) were assessed in 27 patients of whom 17 (group 1) underwent emergent CABG and 10 (group 2) elective between Jan 1984 to Aug 1990. As a whole, history of myocardial infarction (24/27, 88.9%), large left ventricular volume with reduced ejection fraction (LVEDVI 126.08 +/- 25.91 ml/m2, LVESVI 93.04 +/- 21.02 ml/m2, LVEF 25.04 +/- 4.75%) and multiple vessel disease with at least one vessel total occlusion (20/27, 74.1%) were characteristically seen in these patients. The patients of group 1 were significantly older (mean 66.12 +/- 5.68 vs 57.10 +/- 8.08, p < 0.01) and needed more frequent preoperative support with IABP (17/17 vs 4/10, p < 0.01). Using Thallium-201 scintigraphy, in 10 patients of group 1 and 9 of group 2, myocardial viability in the proposed bypass area was evaluated before operations. Average 2.37 +/- 0.79 grafts were placed and continuous retrograde cold blood cardioplegia via the coronary sinus was employed for myocardial protection. Two mitral annuloplasty (MAP) for ischemic mitral regurgitation and 2 cryoablation for the treatment of ventricular tachycardia were performed concomitantly. Operative mortality was 47.1% in group 1 and none in group 2 (p < 0.05). Two cases of MAP died, but two cases of cryoablation survived. Postoperative LVEF was improved significantly only in group 2 (p < 0.05), but during the follow-up period of 7 months to 6 years, all 19 survivors expect one remains with NYHA class I or II.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

[Postoperative conduction disturbances in patients with retrograde continuous cold blood cardioplegia].

Two hundred twenty-seven patients who underwent open heart surgery with retrograde continuous cold blood cardioplegia (RC-CBCP) were investigated to manifest the incidence of postoperative conduction disturbances (CD) and to determine factors related to the occurrence of CD. The incidence of CD in patients with RC-CBCP was 16.7%, which was lower than that (24.4%) in 41 patients with antegrade continuous cold blood cardioplegia. In addition, the CD resolved by the time of hospital discharge in 65% of the patients. There were no patients with new complete atrioventricular block requiring a pacemaker. The development of postoperative CD was related to topical cooling with slushed ice and lower myocardial temperature of the left ventricle, but not to kinds of diseases, duration of aortic cross-clamp, or the distribution of RC-CBCP evaluated from myocardial temperature at the end of initial infusion of cold cardioplegic solution. Furthermore, terminal warm blood cardioplegia reduced the occurrence of CD. We conclude that the occurrence of CD in patients with RC-CBCP is lower than that in patients with antegrade cardioplegia, and is most related to local hypothermia with slushed ice. This suggests that the most likely mechanism for the development of CD would be ischemic or reperfusion injury to the specialized conduction system with the disturbance of microcirculation because of rouleaux formation in CBCP at very low myocardial temperature.

Aged↗

PubMed1992

[Surgical treatment of native valve endocarditis].

Twenty eight patients with native valve endocarditis (NVE) were subjected to this study. Thirteen patients underwent an operation at the chronic phase, and 15 patients at the active phase. One of the 13 patients at the chronic phase died of cardiac rupture due to myocardial infarction which had occurred preoperatively, and one of 10 patients at active phase without annular infection died of rupture of mycotic cerebral aneurysm early postoperatively. Among 5 patients at the active phase with annular infection, prosthetic valve endocarditis occurred in one patient 1.5 months after supraannular aortic valve replacement, and the second operation with a translocation technique was needed. This patient was lost from low output syndrome. Another patient in this group, who underwent a translocation technique because of mycotic annular abscess, died of intestinal infarction late postoperatively. The other 24 patients went a good postoperative course. Five patients with annular infection at the active phase had a shorter duration from the infectious onset to operation (20 days to 2 months, average 38 days), and the causative microorganisms were streptococcus faecalis, staphylococcus epidermidis and gram-negative coccus. One patient, who died of mycotic cerebral aneurysmal rupture, had candida albicans as a causative microorganism. For patients with NVE, an early aggressive operation is essential before infection extends to the annulus or to other vital organs, especially when these microorganisms are identified.

Adult↗

PubMed1992

[Coronary artery bypass grafting in patients with poor left ventricular function using retrograde continuous cold blood cardioplegia].

Patients with poor left ventricular function or those requiring urgent surgery may have more extensive ischemic myocardial injury if myocardial preservation is incomplete. We have performed coronary artery bypass grafting (CABG) aimed at complete revascularization in such cases using RC-CBCP, which is considered more effective on myocardial preservation during aortic cross-clamping in particular to protect ischemic area distal to severe coronary artery stenosis or obstruction. In the present study, in 25 patients with poor left ventricular function (left ventricular ejection fraction; LVEF less than or equal to 0.3) including 10 patients who required urgent surgery, the operative results were evaluated. All the distal and proximal anastomoses of grafts (average 2.5 grafts) were completed during one aortic cross-clamping using RC-CBCP, therefore graft flow was obtained immediately after release of the aortic clamping. Though this method required 142 minutes of a mean aortic cross-clamping time, myocardial protection was considered to be preferable judging from postoperative isoenzymatic evaluation and improved ventricular function. Fifteen patients with elective CABG were all alive and restored to NYHA class I to II. Among 10 patients requiring urgent CABG, 4 patients with acute myocardial infarction died but others were restored to NYHA class I to II. We conclude that it is important to aim at complete coronary revascularization in patients with poor left ventricular function and RC-CBCP achieves more effective myocardial protection during CABG in the patients.

Adult↗

PubMed1992

[Coronary artery bypass grafting using retrograde continuous cold blood cardioplegia].

Coronary artery bypass grafting was performed in 166 patients with severe coronary artery disease using retrograde continuous cold blood cardioplegia (RC-CBCP) during the last 3 years and 8 months. In this study, myocardial protection was assessed from the aspect of enzymatic analyses and clinical results of these patients. Six hospital deaths were not related to the myocardial protection. Even in the groups of patients with medically refractory unstable angina, multiple occlusion of the coronary artery, low cardiac function and left main trunk lesion, RC-CBCP provided excellent protection of the myocardium and satisfactory results of operation as well as in each control group. Consequently we conclude that RC-CBCP affords safer and more effective myocardial protection in patients with severe coronary artery disease.

Adult↗

PubMed1992

[Retrograde continuous cold blood cardioplegia via coronary sinus].

Though the retrograde continuous cold blood cardioplegia (RC-CBCP) is a useful method of myocardial protection for more complicated cardiac surgery, the most important problem is whether the right ventricle is satisfactorily protected or not. In the present study 60 patients with valvular heart disease given RC-CBCP were compared with 30 patients given antegrade continuous cold blood cardioplegia. Judging from myocardial temperature measured in the right ventricular wall, the ventricular septum and the left ventricular wall at the end of initial cardioplegic infusion, myocardial distribution of cardioplegic solution in the RC-CBCP group was as favorable as in the antegrade group. Injury to mitochondria in the right ventricular myocardium observed in the biopsy specimen taken just prior to aortic unclamping was usually trifling in the RC-CBCP group, and was not different significantly from that in the antegrade group. Cold blood cardioplegia dose perfused per left ventricular mass weight (LVMW) had significant correlation with injury to mitochondria, and the dose of more than 5ml/100gLVMW/min seemed to be preferable. There was no hospital death in all patients. Peak CK-MB after unclamping was less in the RC-CBCP group than the antegrade group. In conclusion, RC-CBCP is a safe and effective means of myocardial protection for both right and left ventricles.

Blood↗

PubMed1992

[Clinical appraisal of myocardial protection for coronary artery bypass grafting--efficacy of retrograde continuous cold blood cardioplegia].

Myocardial protection is one of the most important problems during coronary artery bypass grafting in patients with severe coronary artery disease. In this communication we have demonstrated retrograde continuous cold blood cardioplegia (RC-CBCP) in such cases with preferable results. In this study myocardial protection for CABG surgery was evaluated from the points of the myocardial distribution of cardioplegic solution, the changes of the value of myocardial enzyme, the recovery of cardiac function after unclamping of the aorta, and the results of operation [mortality and incidence of perioperative infarction (PMI)]. The effects of myocardial protections were compared among the following 4 groups: group-A (n = 38) where antegrade cardioplegia with 10 ml/min of CBCP was used; group-R (n = 52), retrograde cardioplegia with 10 ml/min of CBCP; group-Rm (n = 59), retrograde cardioplegia with 7-8 ml/100 g LVMW (left ventricular mass weight)/min of CBCP; group-Rmt (n = 65), RC-CBCP with terminal warm blood cardioplegia (TWB). Judging from myocardial temperature measured at the end of initial cardioplegic infusion, the myocardial distribution of cardioplegic solution in group-R was significantly favorable even in the distal area of severe coronary artery stenotic lesions exceeding 90% compared with group-A. The recovery of cardiac function assessed from the incidence of occurrence of spontaneous beating and the dose of cathecholamine at the weaning of cardiopulmonary bypass were most excellent in group-Rmt among the 4 groups. There was no significant difference in postoperative peak CK-MB and LDH-1 isoenzyme levels among the 4 groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

[Two cases of hypertrophic obstructive cardiomyopathy (HOCM) treated with mitral valve replacement].

The first patient was a 60-year-old female who had suffered from several episodes of cardiac failure due to severe mitral regurgitation and HOCM. The patient underwent urgent MVR because she had cardiac tamponade due to left ventricular perforation during cardiac catheterization. The second patient was a 64-year-old female with a history of several cardiac failures. The patient had an operation because she had been symptomatic under medical treatments. She underwent MVR instead of myectomy due to relatively thin ventricular septum. Both of them are doing well after the operations in NYHA class I. Although myotomy and myectomy are preferable procedure for HOCM as a first choice, MVR should be considered for the patients who have severe mitral valve regurgitation or the thin interventricular septum.

Cardiomyopathy, Hypertrophic↗

PubMed1992

[Retro-TH catheter for retrograde coronary sinus perfusion].

Retrograde coronary perfusion via the coronary sinus for myocardial protection can be performed more safely and exactly with Retro-TH catheter (3 way balloon catheter) which was originally designed. In addition, this catheter can be useful for selective cerebral perfusion in patients with aortic aneurysm involving aortic arch and for selective visceral and renal perfusion in patients with thoracoabdominal aneurysm. From January 1987 to March 1992, we performed 735 open-heart surgery, 12 surgery for aortic arch aneurysm and 6 surgery for thoracoabdominal aneurysm with the aid of this catheter and obtained satisfactory results.

Catheterization↗

PubMed1992

[A case of subglottic tracheal stenosis following tracheostomy successfully treated with laryngo-tracheal anastomosis].

A 77-year-old male patient underwent laryngo-tracheal anastomosis for subglottic tracheal stenosis. He developed exertional dyspnea 10 month after tracheostomy. Anterior and lateral wall of the cricoid cartilage and the first two tracheal cartilages were resected, preserving the recurrent laryngeal nerves. The distal trachea was anastomosed to the thyroid cartilage primarily and tracheostomy was made at 6th tracheal ring. Postoperatively, anterior flexion of the neck was maintained for a week. Oral intake was started on the 2nd postoperative day. The patient showed smooth recovery. The important points of this operation are: 1) preoperative evaluation of the residual subglottic space, 2) intraoperative care for preservation of the recurrent nerves, especially at the lateral sides of the crycoid cartilage, and 3) postoperative maintenance of the cervical anterior flexion.

Aged↗

PubMed1992

[Surgical treatment of active infective endocarditis and prosthetic valve endocarditis].

Fifteen patients with active native valve endocarditis (NVE) and 5 with prosthetic valve endocarditis (PVE) were subjected to this study. Among the patients with NVE, one of 10 with simple destruction of leaflets and 2 of 5 with annular infection died postoperatively of cerebral bleeding and persistent infection. Five patients with annular infection, whose microorganisms were Streptococcus faecalis, Staphylococcus epidermidis and gram-negative coccus, had a shorter duration from onset to operation (mean 38 days) compared with the others (mean 85 days). A patient with NVE requires an urgent operation, especially when these microorganisms are identified. Among those with PVE, 3 underwent operation at the active phase and one at the chronic phase. Two patients with mechanical valve endocarditis by Staphylococcus and Candida died, but the other 2 with bioprosthetic valve endocarditis by alpha-Streptococcus survived, because infection was localized in the leaflets. Another patient with mechanical valve endocarditis by alpha-Streptococcus survived with conservative management. While a patient with bioprosthetic valve endocarditis requires an early operation as well as NVE, a patient with mechanical valve endocarditis requires selected management considering the microorganism and general condition.

Adult↗

PubMed1991

A study of haemolytic streptococci isolated from outpatients in dermatological clinics.

A total of 44 patients suspected of streptococcal infections were studied in outpatient clinics in Tokyo during the one year from December 1988 to December 1989. Employing bacteriological culturing and serodiagnosis, the following results were obtained. 1) There were 9 cases of impetigo and 15 cases of erysipelas with typical clinical manifestations and age distributions. 2) It seemed that some of the skin infections were caused by group A streptococci whose M-types were different from those of upper respiratory infections typically occurring in Japan. 3) The type distribution of group A streptococci found were quite similar to those isolated in Thailand or Malaysia. 4) There were found group A streptococci exhibiting unique combinations of T- and M-types, such as T11 and M9, T11 and M62 or T13-49 and MOD8 (Provisional type). 5) As for serodiagnostic method, ADNB (anti-deoxyribonuclease B) titer reflected infection by group A streptococcus only, while ASK (anti-streptokinase) and ASO (anti-streptolysin O) reflected not only group A streptococcal infections but group G infections as well.

Ambulatory Care Facilities↗

PubMed1991

[Pressure monitoring of the coronary sinus during retrograde cardioplegia].

Though the retrograde perfusion via the coronary sinus is a useful way of myocardial protection for more complicated cardiac surgery, coronary venous injury and inadequate preservation of the right ventricle were considered to be disadvantageous. In order to deal effectively with these problems we made a 3-way balloon catheter (Retro-Higami type 12 Fr) and evaluated the importance of monitoring the perfusion pressure in the coronary sinus in 214 patients. The mean perfusion pressure during retrograde cardioplegia infused by a pump was 29.4 +/- 9.1 mmHg, and had significant relation to the left ventricular mass weight (LVMW) which was calculated by UCG method. High perfusion pressure above 40 mmHg, which could have induced coronary venous injury, was noticed in 24 patients, but proper countermeasures could avoid venous injury completely. In 16 of those the high perfusion pressure was due to inadequate position of a tip of the catheter, and in other 8 it was due to relatively high flow rate of cardioplegic solution to LVMW. Twenty-eight patients showed low perfusion pressures below 20 mmHg, due mainly to the leakage from the orifice of the coronary sinus. The coronary sinus pressure during continuous gravity retroperfusion which was 9.2 +/- 2.6 mmHg seemed to bring optimal delivery of cardioplegic solution to the myocardium. On the basis of the results obtained from this clinical study we conclude that the monitoring of coronary sinus pressure during retroperfusion is useful not only to avoid coronary venous injury but to maintain adequate perfusion.

Adult↗