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I Yada

Publications and source records attributed to I Yada.

At least 73 records · Page 4Linked to original sources
PubMed1996

Clinical experience with the Nikkiso centrifugal pump.

The Nikkiso HPM-15 is a minimally sized centrifugal pump. Preliminary results regarding clinical use of this pump for cardiopulmonary bypass (CPB) procedures have been reported previously. Recently, we have managed some additional cases using a newly developed controller. This article reports our clinical experiences with the use of this pump. We have managed 23 cases with a Nikkiso centrifugal pump. Twenty-two patients underwent CPB and 1 patient with fulminant viral myocarditis underwent percutaneous cardiopulmonary support (PCPS). With this pump, the circuit was extremely easy to prepare and deaeration was achieved readily. Hemodynamics during CPB and PCPS were stable in all cases. The increase in serum-free hemoglobin levels during CPB with this pump was as low as that seen in preliminary tests. A decrease in the platelet count was observed after the initiation of CPB with this pump; however, platelet counts returned to preoperative values 7 days after surgery. Moreover, urine output during CPB with this pump was as high as that seen in preliminary tests. No abnormalities in renal or liver function occurred during CPB. It appears that this new centrifugal pump is safe and easy to operate, and we conclude that it is useful for CPB and PCPS.

Adult↗
PubMed1995

Left atrial myxomas. Using gross anatomic tumor types to determine clinical features and coronary angiographic findings.

PURPOSE: To our knowledge, there have been no reports focusing on differences of clinical characteristics according to two gross anatomic types of cardiac myxomas. This study evaluated the differences of clinical features, coronary arteriographic findings, and histopathologic findings. PATIENTS AND METHODS: Twenty-six patients who underwent surgical excisions for left atrial myxomas were analyzed. According to the gross anatomic types, they were divided into two groups: group 1 having solid and ovoid myxomas (n = 14), and group 2 having soft and papillary myxomas (n = 12). Differences of presenting symptoms, prevalence of brain infarction, coronary angiographic findings, and histopathologic findings were analyzed. RESULTS: An incidence of dyspnea was significantly higher in group 1 (78.6% vs 33.3%, p < 0.05) than in group 2. That of neurologic symptoms was higher in group 2 (75% vs 14.3%, p < 0.01) than in group 1. A prevalence of brain infarction was higher in group 2 (75% vs 2.5%, p < 0.05) than in group 1. On coronary angiography, an identification rate of clusters of tortuous vessels was higher in group 1 (81.8% vs 0%, p < 0.01) than in group 2. In histologic findings, most of group 1 tumors displayed many hemorrhages, small vessels, and fibrosis in the stroma, but group 2 had few such structures. CONCLUSIONS: Coronary angiographic findings of tumor-feeding arteries without clusters of tortuous tumor vessels predict a myxoma that is papillary in type. At that time, close attention should be given for the possible existence of silent brain infarction.

Adolescent↗
PubMed1994

Reticuloendothelial function following cardiopulmonary bypass: laboratory and electron microscopy findings.

Several studies on the effects of cardiopulmonary bypass (CPB) on the reticuloendothelial system (RES) function have been performed previously, but different results have been reported. This study was carried out to determine the effect of CPB on RES function in a canine model simulating clinical CPB. Nine dogs undergoing surgery with CPB were compared with an identical number of dogs subjected to thoracotomy without CPB. A lipid emulsion test was performed in all dogs before and after the surgical procedure to measure RES phagocytic index, i.e., phagocytic function. Kupffer cell iron uptake under conditions of iron loading following CPB was examined histologically, and any ultrastructural changes in the Kupffer cells were observed by electron microscopy. In both groups, the RES phagocytic index showed a significant decline after surgery. However, a comparison of the two groups revealed that there was a significantly greater decrease in the CPB group (P < 0.05). Moreover, histologic evidence of iron uptake in Kupffer cells was strongly suppressed in the CPB group. Electron microscopy of the Kupffer cells showed that the number of phagosomes, especially deformed erythrocytes, increased after CPB. These findings suggest that RES function is significantly impaired following CPB, and an increase in the amount of material, especially deformed erythrocytes, to be processed by the RES is responsible, in part, for the depressed RES phagocytic function. The prevention of hemolysis during CPB may preserve the RES function following CPB.

Animals↗
PubMed1994

Is it true that cardiac operations with cardiopulmonary bypass impair the reticuloendothelial system?

Reticuloendothelial system (RES) function after cardiac operations is a controversial issue. Sequential changes in plasma fibronectin levels and RES phagocytic function were studied after a cardiac operation and a lung operation (control). In the cardiac operation group, the plasma fibronectin level decreased until the third postoperative day and increased thereafter. Reticuloendothelial system phagocytic function remained unchanged on the third postoperative day and then it increased. However, in the control group it increased significantly after operation. In the past, investigators have demonstrated a decline in plasma fibronectin levels following cardiac operation and have assumed that RES function was impaired. However, this sequential study showed that phagocytic function was not impaired, but its enhanced phase was delayed. Moreover, our previous morphologic studies demonstrated that RES function was potentially activated after cardiopulmonary bypass. It appears that the delay of the enhanced phase is caused by the overloading of substances which must be processed by the RES during cardiopulmonary bypass. Thus, we conclude that cardiac operation produces hyperactive, yet oversaturated RES function. There is no impairment of RES function after cardiac operations.

Adult↗
PubMed1994

Effects of inhaled nitric oxide in rats with chemically induced pulmonary hypertension.

To determine the model animal with pulmonary hypertension in which nitric oxide (NO) inhalation reduces pulmonary arterial pressure (PAP), we examined the inhalation of 20-100 ppm NO gas on normal rats and rats with monocrotaline induced pulmonary hypertension. In the control group, mean PAP showed no change after spontaneous breathing of NO at the concentration of 20 to 100 ppm for 5 min. On the contrary, in both the severe (mean PAP > 40 mmHg) and moderate (mean PAP < 40 mmHg) pulmonary hypertensive groups, NO inhalation produced a prompt reduction of the mean PAP which had been elevated by monocrotaline. 20 ppm NO inhalation reduced mean PAP from 64.4 +/- 3.7 mmHg to 56.2 +/- 4.4 mmHg (mean +/- SEM, P < 0.01) in the severe pulmonary hypertensive group, from 31.0 +/- 2.0 mmHg to 24.2 +/- 0.9 mmHg in the moderate pulmonary hypertensive group (mean +/- SEM, P < 0.05). The onset of the reduction of mean PAP occurred within 30 sec after the start of NO inhalation and maximum reduction occurred within 4 min. 20 ppm NO inhalation significantly reduced mean PAP, and mean PAP was reduced dose-dependently at the concentration of 20 to 60 ppm and reaction to NO was almost constant at the concentrations of over 60 ppm.

Administration, Inhalation↗
PubMed1994

The effects of single lung transplantation in rats with monocrotaline-induced pulmonary hypertension.

Acute haemodynamic change after single lung transplantation for primary pulmonary hypertension was evaluated using a rat transplantation model. Inbred Fisher 344 rats were administered with 40 mg/kg monocrotaline in order to induce pulmonary hypertension. The rats whose mean pulmonary arterial pressure (PAP) was over 30.0 mm Hg received a left lung isograft from a normal donor after right heart catheterization. In the control group, PAP increased after single lung transplantation. On the other hand, in the pulmonary hypertensive group, PAP was significantly decreased 60 min after the transplantation, but 3 and 6 h after the transplantation, the PAP significantly increased again. On the day after the operation, it again decreased significantly. Left-to-right lung blood flow ratio was significantly increased in rats with pulmonary hypertension compared to rats with normal pulmonary pressure on both the 1st and 3rd postoperative days. The oedema of the grafted lung was more severe in the pulmonary hypertensive group than in the control group in the acute phase. In conclusion, single lung transplantation for pulmonary hypertension shifted pulmonary blood perfusion to the grafted lung and this shift made pulmonary oedema of the grafts more severe in the acute phase. These oedematous changes, which were more pronounced in the grafts in the pulmonary hypertensive rats, might have contributed to the transient rise in PAP in those rats after single lung transplantation.

Animals↗
PubMed1994

Oversaturation status of reticuloendothelial system following cardiopulmonary bypass.

In the past, it was generally believed that the phagocytic function of the reticuloendothelial system (RES) was depressed after cardiopulmonary bypass (CPB), but several investigators reported differing results. Therefore, this study was performed to determine the effect of CPB on RES function, experimentally and clinically. Six dogs undergoing CPB (CPB group) were compared with an identical number of dogs subjected to thoracotomy without CPB (control group). A lipid emulsion test was performed in all dogs before and after the surgical procedure to measure RES phagocytic function. Any ultrastructural changes in Kupffer cells were observed by electron microscopy. In both groups, the RES phagocytic index showed a significant decline after surgery. However, comparison of the 2 groups revealed that there was a significantly greater decrease in the CPB group (p < 0.05). Electron microscopy of the Kupffer cells showed that the number of phagosomes, especially those containing deformed erythrocytes, increased after CPB. Twenty patients undergoing cardiac surgery requiring CPB (Group A) and 8 patients undergoing pulmonary resection (Group B) were studied. RES phagocytic function was determined 3 days prior to surgery and 3 days postoperatively using the lipid emulsion test. No significant difference was observed in the preoperative phagocytic indices between the 2 groups. The phagocytic function remained almost unchanged in Group A on the third postoperative day, compared with the preoperative value, but it increased significantly in Group B on the third postoperative day, compared with the preoperative value. The intergroup difference was significant on the third postoperative day (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Do we really need pulse? Chronic nonpulsatile and pulsatile blood flow: from the exercise response viewpoints.

The response of the body and the blood pump was evaluated in animals with a pulsatile artificial heart (total artificial heart [TAH]) and those with a nonpulsatile artificial heart (nonpulsatile biventricular bypass [NPBVB]) subjected to the same exercise load. The animals used in this study were 5 calves implanted with a pusher-plate type TAH (45-206 days) and 5 calves implanted with a nonpulsatile centrifugal pump (34-99 days). The pre-exercise pump flow rate was 92.1 +/- 8.1 ml/kg/min for the TAH group and 94.8 +/- 9.1 ml/kg/min for the NPBVB group, with no significant difference between the two groups. The workload was administered at a rate of 1.5 mph for 15 min. The artificial heart driving conditions were kept constant throughout the test period. Sequential changes in hemodynamic response and metabolism were determined before, during, and for 30 min after exercise. Both TAH and NPBVB calves showed excellent tolerance of the workload (1.5 mph exercise); in NPBVB calves, oxygen demand was compensated for by an increase in the arteriovenous oxygen difference during exercise; and norepinephrine showed a greater response in the NPBVB group. Based on the results presented, the nonpulsatile pump seems to lend itself to a mechanically driven artificial heart of the complete implantation type because of its small size, high efficiency, and the lack of need for a compliance chamber.

Animals↗
PubMed1994

Surgical treatment of primary lung cancer in patients less than 40 years of age.

PURPOSE AND METHODS: The major purpose of this study was to determine whether the survival rate in young lung cancer patients after surgical treatment differs from that in older patients. An analysis was performed for all patients with bronchogenic carcinoma who underwent surgery at Mie University Hospital from 1965 to 1990. RESULTS: Of 803 patients, 24 (2.99%) were 33 to 39 years old. At the time of surgery, the disease was diagnosed as stage I in seven patients (29%), stage II in four (17%), stage IIIa in seven (29%), stage IIIb in two (8%), and stage IV in four (17%), while 46.3% of the patients older than 40 years of age had either stage IIIa, IIIb, or IV disease. All of the 24 patients less than 40 years of age underwent thoracotomy: curative resection in 14 cases, palliative resection in sex, and probe-thoracotomy in four. The 5-year survival rate for all stages of disease was 31.4% in these 24 patients, and 41.9% in 603 patients greater than 40 years of age. The 5-year survival rate for stage I disease was 35.7% in the seven younger patients and 78.0% in the 207 older patients; for stage II, it was 25.5% in the four younger patients and 40.6% in the 98 older patients; for stage III, it was 33.3% in the nine younger patients and 15.6% in the 250 older patients; and for stage IV, it was 25% in the four younger patients and 6.6% in the 48 older patients. There were no significant differences in survival rate between the two age groups for all patients or for those with each stage of disease. CONCLUSION: Although younger patients tended to have more advanced disease, long-term survival in these patients did not differ from that of older patients.

Adult↗
PubMed1994

Surgery for T4 lung cancer: the prognoses of T4 lung cancer.

The prognoses of T4 lung cancer patients treated surgically were investigated in 76 patients. Extended resection was performed in 21 patients, palliative resection in 21 and exploratory thoracotomy in 34. Although the five-year survival of the extended resection group did not differ significantly from that obtained in the exploratory thoracotomy group, the mean survival time of the extended resection group was 3.1 months longer than that of the exploratory thoracotomy group. Two patients who had undergone resection for left atrial involvement, survived for two years or more, and a T4N0 patient with squamous cell carcinoma, in whom resection for aortic involvement was carried out, died from an unrelated disease after 15 months. Two patients with pleural dissemination, who underwent panpleuropneumonectomy, survived for two years. Surgical intervention did not improve the prognosis of patients with N2-squamous cell carcinoma, those with malignant effusion or those with multiple organ involvement.

Adenocarcinoma↗
PubMed1994

[Successful treatment of a giant bulla by thoracoscopic excision and laser ablation].

A 39-year-old male complaining of shortness of breath on mild exertion. Radiographs revealed that a giant bulla occupied more than half the area of the right lung field. Thoracoscopic excision of the giant bulla was performed using some autosutures. After the emphysematous lesion was consolidated by laser ablation, it was sutured using PDS thread. The bulla in the left lung was similarly excised 3 weeks after the first procedure. The FEV1.0% improved from 72% to 89% after excision and laser ablation of a giant bulla and bullae. Thoracoscopic excision and laser ablation of a giant bulla appears to be an effective alternative to conventional thoracotomy.

Adult↗
PubMed1994

New surgical method of chordal replacement for mitral valve incompetence with echocardiographic guidance. An experimental study.

Chordal replacement with expanded polytetrafluorethylene suture has become a procedure of choice for repairing anterior leaflet prolapse among certain surgeons. However, most surgeons believe that the chordal replacement is too complicated and not reproducible. This report introduces a new method of chordal replacement using intraoperative epicardial and transesophageal echocardiography. Three dogs underwent the following procedures. One major marginal chorda of an anterior mitral leaflet was resected during cardiopulmonary bypass. A specially designed 3-0 polytetrafluoroethylene suture, having straight needles, was attached to the anterior leaflet by a mattress suture. Then the needles were brought from the root of the anterior papillary muscle to the outside of the left ventricle. After the bypass flow was reduced, both ends of the polytetrafluoroethylene suture were pulled under echocardiographic guidance until valve competence was achieved. At that point, the suture was temporarily tied. When cardiopulmonary bypass was discontinued, competence was again confirmed and the suture was tied permanently. When the procedures were completed, echocardiography showed trivial regurgitation and good pliability of the anterior leaflets in all animals. Left atrial pressures were sufficiently decreased. It appears that this new technique is reproducible for all surgeons because the optimal length of polytetrafluoroethylene chordae is determined with the valve functioning.

Animals↗
PubMed1993

Effect of nicardipine on pulmonary hypertension after repair of congenital heart defects in early postoperative period.

We examined the effect of nicardipine and hyperventilatin on pulmonary arterial pressure (PAP) in four patients with pulmonary hypertension in congenital heart defect especially in the early postoperative period. There was a significant positive correlation between the values of arterial carbon dioxide tension (PaCO2) and the ratio of mean PAP to mean systemic arterial pressure (Pp/Ps) in two patients whose Heath Edwards classification was Grade II; one of them also had 20% reduction of mean PAP by nicardipine without changing mean arterial pressure. In the remaining two patients showing no correlation between the values of PaCO2 and Pp/Ps, nicardipine did not reduce PAP. Although nicardipine reduced PAP without changing systemic arterial pressure in only one out of four patients, these results suggest that nicardipine may be a drug for control of PAP during weaning phase from the ventilator especially in patients whose PAP decreases under hyperventilation.

Journal Article↗
PubMed1993

Clinical experience using the Bio-pump for extracorporeal circulation during open-heart surgery.

The Bio-pump is still being used in a wide range of clinical applications such as open-heart surgery, left-heart bypass, extracorporeal membrane oxygenation, and supplementary circulation. Clinical application of the Bio-pump for extracorporeal circulation in 21 patients undergoing open-heart surgery was compared with application of the roller pump in terms of their effects on hemolysis, platelet function, and renal function. Although the amount of hemolysis was not significantly different between the Bio-pump group and the roller-pump group, platelet function was slightly better maintained in the Bio-pump group as judged by the levels of platelet factor 4, beta-thromboglobulin, and 6-keto-prostaglandin F1 alpha/thromboxane B2. There was no difference between the two pumps in terms of their effects on renal function. The above findings lead us to conclude that there is a slight advantage to use of the Bio-pump in clinical settings.

Blood Platelets↗
PubMed1993

Aneurysm of the inferior mesenteric artery.

The case of a 48-year-old man with an aneurysm of the inferior mesenteric artery is described. This aneurysm was associated with extensive vascular disease characterized by multiple sites of stenosis and occlusion in addition to an upper abdominal aortic aneurysm. Repair of both aneurysms and reconstruction of the left renal artery and inferior mesenteric artery, which supplied all splanchnic circulation, were performed. The aetiology of the disease was thought to involve Takayasu's arteritis.

Aneurysm↗