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Biomedical subjects

R Tominaga

Publications and source records attributed to R Tominaga.

At least 37 records · Page 2Linked to original sources
PubMed1999

Comparative study of retrograde and selective cerebral perfusion with transcranial Doppler.

BACKGROUND: Retrograde cerebral perfusion (RCP) is a simple technique and is expected to provide cerebral protection. However, its optimum management and limitations remain unclear. Transcranial Doppler has been used to monitor cerebral perfusion. Using this Doppler technique, we compared cerebral blood flow for RCP with that for selective cerebral perfusion. METHODS: Thirty-two consecutive patients underwent elective surgical repair of an aortic aneurysm involving the aortic arch at Kyushu University Hospital. Retrograde cerebral perfusion was used in 15 patients and selective cerebral perfusion, in 17 patients. Continuous measurement of middle cerebral artery blood flow velocities was performed by transcranial Doppler technique. RESULTS: Retrograde middle cerebral artery blood flow velocities during RCP could be measured in only 3 patients, whereas middle cerebral artery blood flow velocities during selective cerebral perfusion could be measured in all but 1 woman. The increase in middle cerebral artery blood flow velocities after RCP was significantly greater than that after selective cerebral perfusion. CONCLUSIONS: The measurement of middle cerebral artery blood flow velocities with transcranial Doppler technique is practicable during selective cerebral perfusion but difficult during RCP. The increase in middle cerebral artery blood flow velocities after RCP indicates reactive hyperemia and reflects the critical decrease in cerebral blood flow during this type of perfusion.

Adult↗
PubMed1999

Use of transesophageal echocardiography for postoperative evaluation of right ventricular function.

BACKGROUND: No method has been available to assess the right ventricular (RV) pressure-volume relation in the operating room or intensive care unit. Left ventricular cross-sectional area measured by echocardiography using the technology of automated border detection has been used to construct left ventricular pressure-area (P-A) loops. In the human right ventricle, however, this approach has not been validated. METHODS: We recorded RV P-A loops in 14 patients in the intensive care unit using transesophageal echocardiography. Multiple RV P-A loops were obtained by reducing preload with intravenous nitroglycerin, thereby elucidating the end-systolic P-A relation. RESULTS: With an incremental dose of dobutamine, the slope of the RV end-systolic P-A relation increased (from 4.56+/-2.42 to 7.34+/-3.62 mm Hg/cm2, p<0.01), with no change in the x-axis intercept, which implied increased contractility. Furthermore, in the operating room we validated the use of RV cross-sectional area as a surrogate for RV volume by demonstrating the close correlation between the stroke area (maximal RV area minus minimal RV area) and stroke volume (r = 0.962; p<0.0001). CONCLUSIONS: Transesophageal echocardiography with automated border detection is a promising tool for elucidating RV function through the analysis of RV P-A loops.

Adult↗
PubMed1999

Nitroglycerin as a nitric oxide donor accelerates lipid peroxidation but preserves ventricular function in a canine model of orthotopic heart transplantation.

BACKGROUND: Nitric oxide has cardioprotective effects through several mechanisms. However, nitric oxide may have deleterious effects in the presence of superoxide because it is converted to peroxynitrite, which then initiates lipid peroxidation. Using a canine model of orthotopic heart transplantation, we examined whether adding an organic nitric oxide donor, nitroglycerin, to preservation solution elicits lipid peroxidation after reperfusion and causes deleterious effects on coronary endothelial function and left ventricular function. METHODS AND RESULTS: The donor heart was preserved for 24 hours in cold University of Wisconsin solution with nitroglycerin (0.1 mg/mL) supplementation (group NTG, n = 8) or in standard University of Wisconsin solution (group C, n = 8). After reperfusion, changes of coronary resistance were measured during the infusion of acetylcholine (0.1 mg/min) and of sodium nitroprusside (1 mg/min), and percent coronary relaxation was calculated. Left ventricular function was evaluated by pressure-volume relations with the use of a conductance catheter, thereby deriving the slopes of end-systolic pressure-volume relation, stroke work-end-diastolic volume relation, and maximum rate of change of left ventricular pressure-end-diastolic volume relation. Serum lipid peroxide level was measured. Percent coronary relaxation was similar for the 2 groups. The slopes of end-systolic pressure-volume relation, stroke work-end-diastolic volume relation, and maximum rate of change of left ventricular pressure-end-diastolic volume relation in group NTG were significantly higher than those in group C. On the other side, serum lipid peroxide level in group NTG was significantly higher than that in group C. CONCLUSIONS: Nitroglycerin may have detrimental effects evidenced by the increase in lipid peroxidation, which implied peroxynitrite formation. However, the overall effect of nitroglycerin was cardioprotective. Although the exact mechanism is yet to be clarified, the superb cardioprotective effect of nitroglycerin overwhelms the exaggeration of lipid peroxidation.

Animals↗
PubMed1999

Occurrence of cello-oligosaccharides in the apoplast of auxin-treated pea stems

Treatment of pea (Pisum sativum L.) hypocotyl segments with indole-3-butyric acid, which promotes segment elongation, increased the solubilization of both xyloglucan and cello-oligosaccharides in the apoplast of auxin-treated pea stems. The cello-oligosaccharides were isolated from the apoplastic solution with a charcoal/Celite column and were identified as cellobiose, cellotriose, and cellotetraose after subsequent thin-layer chromatography and paper electrophoresis. Cello-oligosaccharides in the apoplastic fraction were monitored using cellobiose dehydrogenase. Both xyloglucan and cello-oligosaccharides appeared to be formed concurrently within 30 min after treatment with the auxin, and the cello-oligosaccharides increased with stem elongation even after 2 h. The total activity of cellulase did not increase for up to 4 h.

Journal Article↗
PubMed1999

Acute type A aortic dissection involving the left main trunk of the coronary artery--a report of two successful cases.

This report describes 2 cases of a type A acute aortic dissection combined with myocardial infarction caused by a retrograde dissection into the left main trunk of the coronary artery. Successful surgical treatments, including the replacement of the ascending aorta, aortic valve resuspension and coronary artery bypass grafting, were performed in both patients, and they recovered well from cardiogenic shock. However, left ventricular function of both patients remained depressed postoperatively, which limited their quality of life. Because no definite method for salvaging infarcted myocardium has yet been established, either more timely surgery or the preoperative placement of a perfusion catheter in the left main coronary artery is mandatory.

Acute Disease↗
PubMed1999

[Clinical results of mitral valve surgery in children].

The clinical results of mitral valve surgery in children were evaluated. Fifty children (age ranged between 1 month and 12 years) with mitral valve regurgitation have undergone valve surgery with low operative mortality (2%). Valve plasty using several techniques including annuloplasty have been performed with quite high success rate (92%), while valve replacement was required in four patients who had the prolapse of the anterior mitral leaflet (8%). Reoperation was required in 5 patients (10%), and there were 4 late deaths. Introduction of the reconstructive technique of the chordae tendinae using artificial chordae resulted 100% success rate of mitral repair for the prolapse of the anterior mitral leaflet without death and reoperation. The reoperation free rate and the actuarial survival rate at 15 years of the patients with mitral regurgitation were 70 +/- 12% and 85 +/- 7%, respectively. In ten patients with mitral valve stenosis (age ranged between 1 month and 5 years), 5 patients required valve replacement (50%), and 2 patients died (20%). The clinical results of the surgery for the mitral stenosis were still unsatisfactory, and the reoperation free rate at 2 years was 42 +/- 30% and the actuarial survival rate at 13 years were 32 +/- 18%.

Blood Vessel Prosthesis↗
PubMed1999

Extended resection of the pulmonary artery and the aorta for primary lung cancer. Report of a case.

We report a case of squamous cell carcinoma of the lung in which a left pneumonectomy combined resection of the pulmonary artery and aorta was performed using a cardiopulmonary bypass. The bifurcation of the pulmonary artery was repaired with a pericardial patch and the descending aorta was replaced with an artificial vessel Eleven months later, the patient underwent dissection of the contralateral mediastinal lymph nodes because of a recurrence of the disease. Even though pulmonary metastases have again recently appeared, he is alive and doing well two years after operation. To obtain a better prognosis in cases demonstrating an involvement of the bifurcation of pulmonary artery, more effective combined treatment still needs to be developed.

Adult↗
PubMed1998

Prostaglandin E1 from the tip of an intraaortic balloon catheter for lower limb ischemia.

A method to treat lower limb ischemia associated with the insertion of an intraaortic balloon catheter is herein reported. A low dose of prostaglandin E1 was administered into the descending aorta continuously from the tip of the intraaortic balloon catheter. Immediately after the administration of prostaglandin E1 in patients whose lower limbs were ischemic due to obstruction with the catheter, the peripheral circulation of the ischemic limbs recovered with minimal changes in the systemic arterial blood pressure. This method is simple and noninvasive and was found to induce a satisfactory effect.

Alprostadil↗
PubMed1998

Mixed type of total anomalous pulmonary venous connection.

BACKGROUND: The mixed type of total anomalous pulmonary venous connection is a rare condition in which some diagnostic and surgical problems still remain to be solved. METHODS: In 9 patients a single pulmonary vein was connected to the systemic vein at a site different from the drainage site of the confluence of three other pulmonary veins. In 2 other patients, four pulmonary veins made a confluence which had two drainage sites. Correct diagnosis was made in all 7 patients who received cardiac catheterization but only in 5 of the 9 patients by color Doppler echocardiography. Total correction was performed in 3 patients and the single anomalous pulmonary vein was left uncorrected in 8 other patients. RESULTS: There were two in-hospital deaths. Seven patients with a single residual anomalous pulmonary vein have been in good condition without clinical symptoms of congestive heart failure or pulmonary hypertension. CONCLUSIONS: Diagnosis of mixed type of total anomalous pulmonary venous correction by echocardiography is sometimes difficult. When a mixed type is suspected, cardiac catheterization is recommended if the condition of the patient permits it. A single anomalous pulmonary vein may be left uncorrected without serious complications, but close observation is needed to prevent congestive heart failure and pulmonary vascular obstructive disease.

Cardiac Catheterization↗
PubMed1998

Lazaroid U74500A is superior to U74006F in preserving rabbit heart for 24 hours.

BACKGROUND: Lazaroid, a series of 21-aminosteroids, has been shown to reduce free-radical-mediated injury after ischemia and reperfusion. Recent in vitro studies have demonstrated that, among the various compounds studied, the most efficient agent was U74500A. The question is whether these findings apply to the whole heart experiencing ischemia-reperfusion injury. In this study we compared the myocardial protective effects of U74006F, the only clinical candidate, and U74500A. METHODS: An isolated rabbit heart preparation perfused with the blood from a support rabbit was used. All hearts were divided into three groups according to the administration of U74500A (4 mg/kg, group A; n = 7), U74006F (4 mg/kg, group F; n = 7), or solvent (group S; n = 7) to the donor rabbit before preservation. After 24 hours of preservation with University of Wisconsin solution at 0 degrees C, all hearts were perfused with cross-circulated blood for 60 minutes with the Langendorff mode followed by 40 minutes in the working mode. RESULTS: After 10 minutes of reperfusion the serum lipid peroxide levels were significantly (p < 0.05) lower in group A (0.62+/-0.31 nmol/mL) than those in group S (2.1+/-1.3 nmol/mL) and group F (1.0+/-0.6 nmol/mL). The aortic flow rate at 10 mm Hg of left atrial pressure was significantly higher in group A (164+/-37 mL/min) than that of other groups (71+/-28 mL/min in group S and 97+/-28 mL/min in group F). There were no significant differences in high-energy phosphate levels after reperfusion among the three groups. CONCLUSION: These data imply that U74500A inhibits lipid peroxidation and prevents ischemia-reperfusion injury more efficiently than U74006F.

Animals↗
PubMed1998

Effects of amrinone, a phosphodiesterase inhibitor, on right ventricular/arterial coupling immediately after cardiac operations.

OBJECTIVE: Amrinone, a selective phosphodiesterase III inhibitor, is reported to have a potent inotropic effect on the left ventricle, but the effects of this drug on right ventricular contractility in the clinical setting are unknown. The concept of ventricular/arterial coupling was applied to investigate the effects of amrinone on right ventricular contractility and afterload with transesophageal echocardiography. METHODS AND RESULTS: The study was performed in the intensive care unit with 11 patients who had undergone cardiac operations. Right ventricular cross-sectional area was measured with transesophageal echocardiography equipped with a capability of automated border detection as a surrogate for right ventricular volume. Multiple pressure-area loops were obtained by reducing preload to measure end-systolic elastance and effective arterial elastance. External work and pressure-volume area were also measured to calculate the efficiency of energy transfer from pressure-volume area to external work. Nitroprusside (0.3 to 0.5 microg x kg(-1) x min(-1)) and amrinone (1 mg x kg(-1) intravenously followed by 10 microg x kg(-1) x min(-1)) were administered. With nitroprusside infusion, end-systolic elastance and effective arterial elastance remained unchanged (end-systolic elastance, 4.73 +/- 2.18 mm Hg/cm2 to 4.65 +/- 2.09 mm Hg/cm2; effective arterial elastance, 8.05 +/- 3.84 mm Hg/cm2 to 7.70 +/- 3.64 mm Hg/cm2). In contrast, amrinone reduced afterload (effective arterial elastance, 8.82 +/- 3.99 mm Hg/cm2 to 7.05 +/- 4.01 mm Hg/cm2, p = 0.004) and enhanced contractility (end-systolic elastance, 4.47 +/- 1.79 mm Hg/cm2 to 6.56 +/- 2.22 mm Hg/cm2, p = 0.007). Consequently, amrinone decreased the ventricular/arterial coupling ratio (effective arterial elastance/end-systolic elastance, 2.40 +/- 1.45 to 1.16 +/- 0.63, p = 0.009) and improved the efficiency of energy transfer (external work/pressure-volume area, 0.44 +/- 0.15 to 0.54 +/- 0.15, p = 0.013). CONCLUSIONS: Right ventricular pressure-area relations obtained with transesophageal echocardiography could successfully separate the simultaneous change in right ventricular systolic mechanics and afterload caused by amrinone. Amrinone caused enhancement of right ventricular contractility and afterload reduction.

Adult↗
PubMed1998

Increase in the peripheral lymphocyte populations expressing CD54 (ICAM-1) after hyperthermic isolated limb perfusion in patients with malignant melanoma: an analysis of four cases.

The lymphocytes isolated from perfused or non-perfused circulations before, during, and after hyperthermic isolated limb perfusion (HILP) in the four patients with malignant melanoma were analysed for the expression of CD54 (ICAM-1), CD58 (LFA-3), CD4, CD8, HLA class I and class II in order to investigate the mechanism(s) of the activation of such immunocompetent cells as natural killer (NK)-cells or T-lymphocytes by HILP. It was thus found that the lymphocyte populations expressing CD54 increased significantly 1 day after HILP in the four patients examined. The lymphocyte populations expressing CD58 apparently increased. It was also found that the NK-cell and T-lymphocyte activities increased during or after HILP in the present four cases as observed previously in the other melanoma patients. These results indicate that our HILP system may augment the immunological activities through the mechanisms of the induction of CD54 or CD58 expression in the peripheral lymphocytes of the melanoma patients who receive HILP.

Adult↗
PubMed1998

Arresting donor hearts with extracellular-type cardioplegia prevents vasoconstriction induced by UW solution.

The effects of arresting donor hearts with University of Wisconsin solution was investigated. Donor dogs were divided into two groups according to the technique used for arresting the heart. In group I (n = 6) the heart was arrested with University of Wisconsin solution, whereas in group II (n = 6) extracellular-type cardioplegia (K+ = 20 mmol/liter) was used to induce cardioplegic arrest. Aortic root pressure was measured during the infusion of solution at constant flow. In both groups, the hearts were then flushed and stored in cold University of Wisconsin solution for 6 h. The hearts were transplanted orthotopically and disconnected from cardiopulmonary bypass. Left ventricular function was evaluated by pressure-volume relations using a conductance catheter. Peak aortic root pressure during the infusion was significantly higher in group I than in group II, although post-transplant left ventricular function was similar in both groups. Although there was no difference in cardiac function after implantation, donor hearts should be arrested by extracellular-type cardioplegia to prevent coronary vasoconstriction associated with preservation in University of Wisconsin solution.

Adenosine↗
PubMed1998

Antibody-dependent enhancement of feline infectious peritonitis virus infection in feline alveolar macrophages and human monocyte cell line U937 by serum of cats experimentally or naturally infected with feline coronavirus.

Infection of the type II feline infectious peritonitis virus (FIPV) strain 79-1146 to primary feline alveolar macrophages and human monocyte cell line U937 was enhanced by the sera of cats experimentally infected with the 79-1146 strain, but not those of cats infected with KU-2 or UCD-1 strain of type I FIPV. The experiments using sera of cats with feline infectious peritonitis (FIP) and of cats naturally infected with feline coronavirus (FCoV) revealed that infection of the FIPV 79-1146 strain to the U937 cells was enhanced only by the sera of cats infected with type II FIPV or feline enteric coronavirus. The samples positive for antibody-dependent enhancement (ADE) activity had high neutralizing antibody titers against the FIPV 79-1146 strain and the samples negative for ADE activity had low neutralizing antibody titers. These findings support the previous results where a monoclonal antibody with neutralizing activity had high ADE activity, suggesting that there was a close relationship between the neutralization and enhancement sites. And then it is also suggested that ADE of infection is likely to be induced by re-infection with the same serotype of virus in type II FIPV infection. Furthermore, U937 cells are considered useful and can be substituted for the feline macrophages for determining ADE of FIPV-infection.

Animals↗
PubMed1997

Mitral valve repair for isolated double-orifice mitral valve with torn chordae.

Double-orifice mitral valve is an unusual condition of importance to surgeons, and usually associated with other cardiac anomalies. This article reports a case of isolated double-outlet mitral valve with torn chordae in which we successfully performed mitral valvuloplasty by placement of artificial chordae. The mitral valve was divided into anterolateral and posteromedial orifices by vertical bridging tissue. Two torn chordae at the posteromedial scallop surrounding the posteromedial mitral orifice were replaced with artificial chordae of two pairs of expanded polytetrafluoroethylene sutures. Because replacement of torn chordae with artificial chordae was not complicated and seemed to preserve very fine relationships among leaflet tissues, bridging tissue, chordae, and papillary muscles, we suggest this method may be used to reconstruct various kinds of mitral lesions causing mitral regurgitation.

Chordae Tendineae↗
PubMed1997

Kinetics of immunological parameters in patients with malignant melanoma treated with hyperthermic isolated limb perfusion.

Kinetics of immunological parameters such as natural killer (NK) cell activity and tritium-thymidine uptake rate of T lymphocytes by phytohemagglutinin stimulation were investigated using peripheral leukocyte fractions of melanoma patients treated with hyperthermic isolated limb perfusion (HILP). Also, serum concentrations of soluble intercellular adhesion molecule-1 (sICAM-1) were quantified during and after HILP. It was found that NK cell activity was augmented during HILP, and T lymphocyte function was stimulated 24 h and 1 week after HILP with statistical significance. NK cell activities in the cells isolated from perfused and non-perfused circulations were equally augmented during HILP in two patients examined. Serum concentrations of sICAM-1 in the patients who received HILP also increased 24 h or even 1 week after HILP. The stimulation of these immune competent cells and upregulation of sICAM-1 by HILP were independent of the stages of melanoma patients at the time of HILP or the doses of agents which were used for the infusion during HILP. The origin of cells which shed sICAM-1 into the serum of the patients who received HILP remains to be further investigated.

Adult↗
PubMed1997

Removal of retained air during cardiac surgery with transesophageal echocardiography and capnography.

STUDY OBJECTIVE: To evaluate a new method for removal of retained air at the end of cardiopulmonary bypass (CPB) by end-tidal CO2 pressure (PETCO2) and pulmonary arterial pressure (PAP) monitoring, and transesophageal two-dimensional echocardiography (TEE). DESIGN: Prospective study. SETTING: Cardiac surgery unit at a university hospital. PATIENTS: 36 ASA physical status I, II, III patients for open heart surgery. INTERVENTIONS: The CPB reservoir was gradually raised to decrease venous drainage. Accordingly, the right heart began to receive the venous blood and eject it to the pulmonary artery. The vent existing in the left ventricle or the left atrium then collected any whole blood containing air bubbles that came from the pulmonary circulation. The air bubbles were confirmed by TEE to be removed and not to eject from the left ventricle to te systemic circulation. MEASUREMENTS AND MAIN RESULTS: Levels of PETCO2, PaCO2, PAP, and the duration of the removal procedure were measured when a sufficient pulmonary circulation was established and the removal of retained air was considered to be satisfactorily accomplished by the absence of air bubbles, confirmed by TEE for more than 30 seconds. PETCO2 reached 28 +/- 4 mmHg during the removal of air, while PaCO2 reached 35 +/- 6 mmHg (p < 0.05). Mean PAP during removal of air reached 18 +/- 4 mmHg, which was approximately 90% of that before CPB. The duration time of removal of air was 9 +/- 2 min. CONCLUSIONS: PETCO2 and PAP are useful indicators of pulmonary circulation during this procedure for removal of air. PETCO2 of 25 to 30 mmHg and PAP of 90% of the prebypass level have been found to be necessary for the removal of air. Our technique for removal of air using PETCO2, PAP, and TEE enables us to satisfactorily eliminate residual air.

Adolescent↗