Biomedical subjects

Y Senoo

Publications and source records attributed to Y Senoo.

At least 37 records · Page 2Linked to original sources

PubMed1992

Factors influencing the efficacy of DeVega's annuloplasty for secondary tricuspid regurgitation.

DeVega's annuloplasty was performed on 41 patients with tricuspid regurgitation (TR) associated with combined valvular disease and results were assessed based on Doppler echocardiographic findings in an attempt to examine the applicability of this surgical technique. TR was quantitatively evaluated via Doppler echocardiography before and after surgery. Clinical symptoms, cardiac function, and surgical results were assessed, and the severity of left ventricular myocardial degeneration was determined using electron microscopy. There were no differences in the following factors between the TR recurrence and TR improvement groups: previous heart surgery, number of involved valves, presence or absence of a giant left atrium, preoperative New York Heart Association (NYHA) functional class, and type of prosthetic valve (Björk-Shiley vs. St. Jude Medical). We found no differences between these two groups in TR severity and tricuspid annulus diameter measured during surgery. Severity of myocardial degeneration was closely associated with the recurrence of TR. Clinically, most had diminished cardiac function before surgery. DeVega's technique appears to be remarkably effective in patients with well-preserved myocardium because no TR recurrence was detected even in examinations with the most accurate Doppler echocardiography. However, such long-term effectiveness of DeVega's technique cannot be expected in patients with degenerated myocardium.

Adult↗

PubMed1992

Hemodynamic performance of the biventricular bypass system operated in an independent variable rate mode.

The present study was undertaken to determine whether a biventricular bypass system operated in an independent variable rate (VR) mode can maintain the entire circulation. Two pusher-plate pumps which incorporated the Hall effect position sensors were used to bypass the right and left ventricles in 10 sheep under fibrillation. The flow distributions of the pump output to the carotid and renal arteries were investigated every 6 h using ultrasonic blood flow meters for 24 h in 5 animals, and the controllability of the VR mode was evaluated in 5 long-term experiments. The carotid artery flow ratio to the pump output decreased significantly from 4.7 +/- 0.8% before the bypass to 2.7 +/- 0.9% after 24 h. However, the renal artery flow ratio did not change throughout the experiments. In the long-term experiments, the animals were kept alive from 3 to 48 days (mean 15.6 days). The mean pump output had been maintained at more than 90 ml/min/kg for the first 7 days. After the surgery, the pump driving conditions were not readjusted in any experiment. The results indicate that the biventricular bypass system operated in the independent VR mode automatically maintains the entire circulation at a satisfactory level.

Animals↗

PubMed1992

Effect of left atrial plication for the giant left atrium on left ventricular function.

Left atrial plication (LAP) following Kawazoe's method was performed on eight patients with mitral valve stenosis associated with a giant left atrium. To investigate the effect of LAP particularly on left ventricular function, the preoperative and postoperative left ventricular function in these patients were compared. The data were also compared to that of the non-left atrial plication (non-LAP) group with left atrial dimension of 60 mm or over. In the LAP group, there were significant differences between preoperative and postoperative data in the following parameters; New York Heart Association (NYHA) class, cardiothoracic ratio, mean pulmonary arterial pressure (PAP), left ventricular end-diastolic pressure (LVEDP), left atrial dimension, stroke volume index, ejection fraction and cardiac index. On the contrary, in the non-LAP group, there were significant differences between preoperative and post-operative data in the following two factors; NYHA class and PAP. The size of the left atrium in the non-LAP group remained unchanged over the course of long-term follow-up. Despite severe clinical symptoms and severely reduced cardiac function of the patients in the LAP group, cardiac function in all patients improved satisfactorily. This suggests that left atrial plication has a considerably beneficial effect on left ventricular function, and therefore, may be recommended for patients with a giant left atrium.

Adult↗

PubMed1992

Difference of rejection between heart and heart-lung transplantation in rats: flowcytometric analysis of graft infiltrating lymphocyte subsets.

Reported clinical and experimental observations indicate that heart grafts in combined heart-lung transplantation are less frequently rejected than heart grafts transplanted alone. In order to elucidate the mechanism of this difference, twenty-eight inbred male Lewis rats receiving heterotopic allografts from inbred male Fisher rats were evaluated for surface markers of graft infiltrating lymphocytes (GIL) and peripheral blood lymphocytes (PBL) using flowcytometry. Monoclonal antibodies investigated in this study were W3/25 (anti-helper T lymphocyte), OX8 (anti-suppressor/cytotoxic T lymphocyte), OX39 (anti-interleukin 2 receptor), and OX6 (anti-MHC class II antigen). In the acute study, a heart transplanted group (n = 7) and a heart-lung transplanted group (n = 7) without immunosuppression were studied. In the chronic study, cyclosporine (10 mg/kg/day i.m.) were administered in the heart transplanted group (n = 7) and the heart-lung transplanted group (n = 7). Both in the acute and chronic studies, the proportion of W3/25 positive cells in GIL of heart grafts of the heart transplanted group was significantly higher than that of heart grafts and lung grafts of the heart-lung transplanted group. OX8 positive cell proportion in GIL of heart grafts and lung grafts of the heart-lung transplanted group were significantly higher than that of heart grafts of the heart transplanted group. These results lead us to speculate that suppressor T lymphocytes are an important distinguishing factor in the rejection processes of heart allografts and heart-lung allografts as observed in clinical experience.

Animals↗

PubMed1992

[Coronary revascularization with bilateral internal thoracic artery grafts].

Thirty-two patients underwent coronary revascularization with bilateral internal thoracic artery (ITA) grafts. Each patient received 2.7 grafts in average including double ITA grafts. Seventeen patients had the right ITAs as free grafts. The other sixteen were treated with 13 autologous veins and 9 right gastroepiploic arteries in addition. Fifty-five grafts out of 56 (98.2%) were proved to be patent at the time of hospital discharge. The postoperative morbidity included three reoperations for bleeding and one perioperative inferior myocardial infarction. One patient died of colon perforation after surgery and another died of cerebral infarction late after surgery. These results exhibited that coronary artery bypass grafting with bilateral ITA grafts had relatively low risks and could contribute to complete revascularization in patients with diseased coronary arteries.

Aged↗

PubMed1992

[Report of three cases of emergency surgical salvage for acute pulmonary embolism].

Pulmonary embolism (PE) is one of the increasing diseases in Japan, which is aggravated rapidly and early diagnosis is necessary to improve its prognosis. We experienced three cases of successful surgical salvage. It is emphasized that the Doppler ultrasonic echocardiography plays important part in diagnosing PE early and noninvasively. Namely, it shows a appearance of acute cor pulmonale, and is usually able to guess the pulmonary artery pressure by using the simplified formula of Bernoulli's equation. We believe that the surgical pulmonary embolectomy under the cardiopulmonary bypass should be immediately considered in case of unsatisfactory conservative thrombolytic therapy.

Acute Disease↗

PubMed1991

A sheep survived for 48 days with the biventricular bypass type total artificial heart.

A biventricular bypass type total artificial heart (BVB-TAH) utilizing two pusher-plate pumps was developed and implanted in a sheep for 48 days with excellent results. A Hall effect sensor was utilized to operate each pump independently with a full stroke at variable rates (VR). With this system, the animal's hemodynamics was kept physiologically, and all metabolic parameters except hemoglobin and hematocrit returned to normal three weeks after implantation. However, signs of infection appeared on the forty-second day, and consequently the animal fell into a state of shock. Even at that time the BVB-TAH maintained circulation by increasing pumping rate automatically. On the forty-eighth day, the animal could not stand and suffered from anuria; the experiment was then terminated after 1,140 h pumping. At autopsy, there was an enlarged heart with an atrophic change, 1,900 ml of pleural effusion, and 3,100ml of ascites fluid. Blood culture taken on the forty-seventh day yielded Acinetobacter calcoaceticus. The BVB-TAH operated in an independent VR mode maintained entire circulation, and has a capability of substituting the native heart function in any situation.

Animals↗

PubMed1991

Use of ventricular assist devices in patients with postcardiotomy shock.

Over the last three years, we have used ventricular assist devices (VAD) in 7 patients. Of these 7, four patients with combined aortic and mitral valvular disease underwent double valve replacement; one patient with annuloaortic ectasia underwent a Cabrol's operation; another had aortic valve replacement; the last patient had triple coronary artery bypass grafts. The only patient who could be weaned from CPB developed cardiogenic shock after the operation. LVADs supported 6 patients for 4 to 8 days and a BVAD supported one patient for 9 days. All patients survived the weaning procedure. Three were discharged from the hospital and survived 7 to 21 months. The 4 other patients died of multiple organ failure. Three of these four suffered from both renal failure and infection, while one patient had arrhythmia and died of ileus. These data suggest that renal failure and major infection can be serious detrimental complications to VAD support.

Adult↗

PubMed1991

Doppler echocardiographic evaluation of Björk-Shiley and St. Jude Medical prostheses in the mitral position.

The left ventricular studies by Doppler echocardiography were performed in 50 patients with a Björk-Shiley (B-S) mitral valve and 50 patients after implantation of a St. Jude Medical (SJM) mitral valve; the effect of valve replacement on the hemodynamic performance at rest and during bicycle exercise was determined from serial echocardiographic data. Twenty-eight patients (56%) of the B-S group and 42 patients (84%) of the SJM group showed a good response to the exercise. There was no significant difference in the effective orifice area at rest among each sizes of the B-S valve. In the SJM valve, on the contrary, the effective valve orifice area increases in parallel to the size of the SJM valve. There was a clear relation between the valve size and pressure gradient. The pressure gradient directly depends on the valve size and the effective orifice area in the SJM valve. High pressure gradient group in both prostheses had a tendency to take negative values of percent increase in stroke volume. Further, there were no cases showing positive values of percent increase in end-diastolic volume among the patients whose pressure gradients were assumed to be more than 10 mmHg at rest. It is suggested that impairment of inflow caused by the artificial valve, prosthetic valve stenosis, is possibly a significant factor causing left ventricular dysfunction, notably a decrease in stroke volume during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Successful use of the centrifugal ventricular assist device for postcardiotomy cardiogenic shock.

A centrifugal pump was successfully used as a left ventricular assist device (LVAD) in a 54-year-old female who developed cardiogenic shock following open heart surgery. Cardiac index prior to the LVAD support was 1.4 l/min/m2 and increased to 3.0 l/min/m2 at removal of the device, which assisted for 88h. She resumed her daily activity 10 months after the operation and is in New York Heart Association functional class I.

Cardiac Surgical Procedures↗

PubMed1991

Protective effects of calmodulin antagonists (trifluoperazine and W-7) on hypothermic ischemic rat hearts.

The cardioprotective effect of calmodulin antagonists, trifluoperazine (TFP) and N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7) was examined on the isolated rat heart exposed to hypothermic and ischemic conditions by measuring distribution of lysosomal enzymes in myocardial cells, and leakage of creatine kinase (CK) during reperfusion and postischemic recovery in myocardial systolic function. Experimental hearts were infused with 20 degrees C Krebs-Henseleit bicarbonate buffer (KHB) or KHB containing TFP or W-7 for 2min every 30min during hypothermic ischemia. After ischemia for 120min at 20 degrees C, rat hearts were reperfused at 37 degrees C for 30min. TFP and W-7 improved functional recovery and prevented CK release. In TFP treated hearts, leakage of lysosomal enzymes was reduced significantly, whereas stabilization of lysosomes by W-7 did not occur. These results suggest that calcium-calmodulin dependent enzymes may play an important role in the development of cellular damage of the myocardium during hypothermic ischemia, although levels of leakage of lysosomal enzymes may be unreliable predictors of functional recovery after hypothermic ischemia.

Acetylglucosaminidase↗

PubMed1991

[Long-term results with total replacement of the ascending aorta and aortic valve].

From 1971 to 1991, 14 patients, 9 male and 5 female patients ranging in age from 25 to 68 years, were operated on for aortic regurgitation associated with an aneurysm of the ascending aorta. The surgical treatment consisted of 6 cases of Wheat operation, 4 cases of Bentall operation, and 7 cases of Cabrol operation. In 7 cases of Cabrol operation, 3 were reoperations following Wheat or Bentall operations. The operative mortality for the entire group was 28% (4 deaths). The operative mortalities for 6 Wheat operations, 4 Bentall operations, and 7 Cabrol operations were 16%, 75%, and 14%, respectively. Ten patients have been followed from 1 month to 20 years (average 9 years). The late mortality has been 4/10. The cumulative survival rate is 63% at 5 years, 52% at 10 years and 19% at 20 years. Cabrol technique for the treatment of annuloaortic ectasia is an alternative method with relatively low mortality and good-term results.

Adult↗

PubMed1990

[Extended hypothermic heart-lung preservation system for cardiopulmonary preservation with retrograde coronary sinus perfusion and lung immersion].

One major restriction of clinical heart-lung transplantation has been the inability to provide extended hypothermic organ preservation. We examined whether core-cooling, retrograde heart perfusion and lung immersion could provide adequate cardiopulmonary preservation. Hence, donor dogs were placed on cardiopulmonary bypass, and rapidly cooled to 15 degrees C. Then heterotopic heart unilateral left lung transplantations were performed. In control group I (n = 5), hearts and lungs were harvested following core-cooling and cardioplegic arrest, and transplanted immediately. In experimental group II (n = 5), heart-lung blocks were similarly excised but stored at 4 degrees C for 12 hours and then transplanted. During preservation, the lungs were immersed in the extracellular solution. For the heart, non-recirculating retrograde coronary sinus perfusion was performed with oxygenated intracellular solution containing perfluorochemicals. Myocardial function determined by the ratio of end-systolic pressure to end-systolic dimension in the experimental group was similar to that in controls. Although pulmonary vascular resistance and extravascular lung water of the experimental group was higher than those in control group, arterial oxygenation was similar in both groups. Thus, extended heart-lung preservation with core-cooling, retrograde heart perfusion and lung immersion technique could be achieved for heart-lung transplantation.

Animals↗

PubMed1990

[A case of mitral stenosis with free floating ball thrombus].

A free floating thrombus in the left atrium is a rare complication of the mitral valvular disease. A 56-year-old woman with mitral stenosis was admitted for cerebral infarction and abdominal pain. A free floating ball thrombus was detected in the left atrium by echocardiography. We performed the emergent open heart surgery for removal of ball thrombus and mitral commissurotomy successfully. The size of thrombus was 4 x 3 x 2 cm. Postoperative course was uneventful.

Female↗

PubMed1990

[Experience of double internal thoracic artery grafts in coronary artery revascularization].

We have started employing two internal thoracic artery grafts in coronary artery revascularization since February 1988. We have carried out seven such operative procedures in a 15 month period since then. Ages ranged from 55 to 67 years with a mean of 60.6. Six patients were male and one patient was female. One patient was in Canadian Cardiovascular Society angina Class I, one in Class II, four in Class III, and one in Class IV, preoperatively. There were no operative deaths. Postoperatively, six patients were in CCS Class I and one was in Class II. All of the internal thoracic artery grafts were patent at hospital discharge in six angiographically examined patients. We feel that use of double internal thoracic artery grafts in coronary revascularization carries minimal additional risk, when performed in selected case.

Aged↗

PubMed1990

[Elective prosthetic valve reoperation to relieve unacceptably high gradient].

Pressure gradients of Lillehei-Kaster valve (13 patients), Omniscience valve (26 patients) and Omnicarbon valve (7 patients) in the aortic position were evaluated by Doppler echocardiography. Twenty-three out of 46 patients revealed unacceptably high gradients. Seven prostheses were removed because the valve design that they had high gradients across them. Clinical findings including left ventricular function and symptoms improved after the reoperation. Patients who underwent aortic valve replacement with this series of valve prostheses should be followed up cautiously.

Aortic Valve↗

PubMed1989

alpha-Fluoromethylhistidine decreases the histamine content of the rat right atrium under the influence of sympathetic activity.

alpha-Fluoromethylhistidine (alpha-FMH; 65 mg/kg, i.p.), a specific inhibitor of histidine decarboxylase, significantly decreased the histamine content of the rat right atrium in a time-dependent manner; the maximal decrease of 22.2% was observed 4 h after injection. However, alpha-FMH had no significant effect on the histamine content of the left atrium or the ventricles. The alpha-FMH-induced decrease in the right atrial histamine content was not observed in rats pretreated with 6-hydroxydopamine (25 mg/kg, i.p.). Two i.p. injections of 10 and 5 mg/kg of propranolol and the cardioselective beta 1-adrenoceptor antagonist metoprolol almost completely inhibited the alpha-FMH-induced histamine decrease. On the other hand, phentolamine (10 mg/kg, i.p.) had no influence on the histamine-decreasing action of alpha-FMH. These results suggest that in the rat right atrium there is a histamine pool where a rapid turnover of histamine is maintained by normal sympathetic activity.

Animals↗

PubMed1989

Oxygen-derived free radical damage in canine heart transplantation.

To study the role of free radical-induced myocardial injury during heart transplantation, five groups of dog hearts were orthotopically transplanted. Control group I and experimental groups II, III, and IV (each n = 8) were reperfused for 1 hr after 49 min of operational ischemia. Control group V (n = 4) remained ischemic for 90 min. In the three experimental groups, the free radical scavengers superoxide dismutase (10 mg/kg; group II), catalase (10 mg/kg; group III), or both (10 mg/kg each; group IV) were administered just before reperfusion and during reperfusion for 1 hr. The generation of free radicals, remained at low levels in all groups during ischemia, but significantly increased when groups I-IV were reperfused. This increase was also associated with an increase in creatinine kinase MB isoenzyme. In the experimental groups, free radical scavengers significantly inhibited the appearance of thiobarbituric acid reactive substances and the release of creatinine kinase MB isoenzyme during reperfusion (P less than 0.05). Regarding cardiac functions, 60 min after the termination of the cardiopulmonary bypass, a significant improvement was demonstrated in the treated groups (P less than 0.05). These results indicate that (1) the generation of oxygen free radicals occurs primarily during reperfusion, (2) both superoxide dismutase and catalase reduce production of free radicals during this time, and (3) combined administration did not provide a greater improvement in cardiac metabolic recovery. This study confirms the efficacy of free radical scavengers during heart transplantation.

Animals↗