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Biomedical subjects

Y Yokote

Publications and source records attributed to Y Yokote.

At least 109 records · Page 6Linked to original sources
PubMed1981

[Scinti-angiographic investigation of aortic dissection (author's transl)].

We perform scinti-angiography regularly in suspected cases of dissecting aneurysms. In our experience, the dissection is well demonstrated by this method. In correctly selected cases, scinti-angiography is a method which is well tolerated by the patient and which carries very little risk, since the complications due to contrast media are absent.

Aortic Dissection↗
PubMed1980

The comparison of hemodynamic effects of concomitant use of intra-aortic balloon pumping and veno-arterial bypass with atrio-arterial bypass.

Atrio-Arterial Bypass (AAB) and concomitant use of Intra-Aortic Balloon Pumping (IABP) and Veno-Arterial Bypass (VAB) were performed, using 7 dogs with induced cardiogenic shock. AAB was established by draining blood from the left atrium and subsequently returning this blood to the carotid artery. VAB was also accomplished by draining blood from the right atrium and then returning this blood to the femoral artery. And bypass flow rates were set at approximately one third of the baseline cardiac output. Evaluation of hemodynamic effects of concomitant use of IABP and VAB was carried out, compared with AAB. The following findings were obtained. 1) In concomitant use, the left ventricular afterload was decreased to lower level (mSPr and TTI) and the total perfusion flow was increased to higher level than in AAB. 2) In AAB the left ventricular preload (mLAP) decreased to lower level than in concomitant use. 3) In concomitant use and AAB, the left ventricular stroke work decreased to the same level.

Animals↗
PubMed1978

Intra-aortic oxygen distribution during veno-arterial bypass (VAB) without oxygenation in circulatory assist.

Right atrium-femoral artery VAB without oxygenation was performed in 7 dogs at 3 different bypass ratios, 15% 30%, and 45%. Respiration and cardiac output were controlled. Precise intra-aortic distributions of PO2 and O2 saturation were determined by means of a PO2 catheter probe and an oxygen analyzer. The following was concluded: 1) The blood pumped from dog heart produced a narrow "mixing zone" in the mid-aorta with the blood pumped from VAB. The area of the "mixing zone" was in the distal half between renal artery and bifurcation at 15% bypass ratio, in the proximal half between renal artery and bifurcation at 30% bypass ratio, and from celiac artery to below renal artery at 45% bypass ratio. It shifted proximally as the bypass ratio increased. 2) In order to supply necessary oxygen to abdominal viscera, it is recommended that the bypass flow should not exceed 30% of the baseline cardiac output.

Animals↗
PubMed1978

Hemodynamic effects of the concomitant use of intra-aortic balloon pumping and venoarterial bypass without oxygenation in cardiogenic shock.

The concomitant use of INTRA-AORTIC BALLOON PUMPING (IABP) and venoarterial bypass (VAB) without oxygenation (VABsO) was performed in 10 experiments using 6 dogs in cardiogenic shock. VABsO was accomplished with the cricuit from the right atrium to the femoral artery and bypass flow rates were set at approximately one third of the baseline cardiac output. Displacement volume of the IABP balloon was 10 or 20 ml. Evaluation of hemodynamic effects of the concomitant use was carried out, as compared with the single use of IABP or VABsO. The following findings were obtained: (1) In the concomitant use, left ventricular afterload decreased, while mean aortic root pressure increased. Increase in total perfusion flow, decrease in mean left atrial pressure and decrease in left ventricular stroke work were shown more effective than each of the single uses. (2) These results suggest that the concomitant use of IABP and VABsO can be used as a second step assisted circulation when IABP is shown uneffective in the case of severe cardiogenic shock.

Animals↗
PubMedDate not supplied

Amino acid utilization during apoptosis in HL-60 cells.

Human promyelocytic leukemia (HL-60), human squamous carcinoma (HSC-2, HSC-4, NA) and rat pheochromocytoma (PC-12) cell lines consumed nonpolar (Leu, Ile, Val, Cys, Met, Phe), neutral polar (Gln, Ser, Thr, Tyr) and basic polar amino acids (Arg, Lys, His), whereas they produced nonpolar (Gly, Pro, Ala) and acidic polar amino acids (Glu). The consumption rate of Ser and Arg by HL-60 cells was significantly higher than that of other cell lines. During apoptosis of HL-60 cells induced by either sodium ascorbate, sodium 5,6-benzylidene-L-ascorbate (SBA) or dopamine, the consumption of nonpolar and polar amino acids (neutral or acidic) generally declined, except for Cys, Met and Arg, whereas the production of Gly and Glu was slightly increased. Since the intracellular concentration of cGMP was not significantly changed before and after ascorbate treatment, nitric oxide might not be involved in the ascorbate-induced apoptosis. The present data demonstrates that consumption rate of nonpolar and polar amino acid, whether neutral, acidic or basic, was reduced almost evenly during the apoptosis induction. This suggests that apoptosis-associated changes in the amino acid utilization might not be significantly affected by ATP depletion, which might be caused by mitochondrial dysfunction.

Adenosine Triphosphate↗
PubMedDate not supplied

Changes in intracellular concentrations of amino acids and polyamines during the apoptosis of HL-60 cells.

Possible changes in the intracellular concentrations of amino acids and polyamines were investigated during the apoptosis of human promyelocytic leukemic HL-60 cells. Treatment of HL-60 cells with sodium 5,6-benzylidene-L-ascorbate (SBA) or sodium ascorbate induced apoptotic cell death characterized by chromatin condensation, nuclear fragmentation, loss of microvilli, and production of numerous vacuoles and apoptotic bodies. The apoptosis was accompanied by a significant increase in the intracellular concentration of almost all neutral and basic amino acids (regardless of their polarity). On the other hand, the concentration of glutamic acid, the most abundant amino acid in the cells, was significantly reduced. These data suggest the reduced amino acid utilization and possible membrane impairment, especially in SBA-treated cells. Among three major polyamines, the intracellular concentration of putrescine rapidly declined, whereas that of spermidine and spermine was almost unchanged during apoptosis. Conversely, the concentration of putrescine, but not that of spermidine and spermine, was significantly increased during the chemically-induced carcinogenesis of mouse liver tissue. The present study demonstrates that the putrescine level is the most sensitive to the proliferation capability of the cells, among three polyamines, and provides an early marker for apoptosis and proliferation.

Amino Acids↗
PubMedDate not supplied

Changes in amino acid pool and utilization during apoptosis in HL-60 cells induced by epigallocatechin gallate or gallic acid.

Recent studies have demonstrated the apoptosis-inducing potential of epigallocatechin gallate (EGCG), a major component of green tea, against various cultured cell lines. By using an amino acid analyzer, we investigated here the possible changes in the amino acid pool and utilization during the apoptosis of HL-60 cells induced by EGCG or gallic acid, a structural unit of tannin. Sublethal concentrations of EGCG initially elevated and then reduced the intracellular concentrations of most of amino acids except for glutamic acid and aspartic acid, whereas lethal concentrations of EGCG continuously reduced these amino acid pools during 6 hours. Both sublethal and lethal concentrations of gallic acid initially elevated and then reduced these amino acid pools. Both inducers elevated the intracellular accumulation and production of arginine and extensively reduced the utilization of other amino acids. These data demonstrate that EGCG showed more severe effects on the amino acid pool and utilization than gallic acid, which may explain, at least in part, the difference in apoptosis-inducing potential between these inducers.

Amino Acids↗
PubMedDate not supplied

Effect of prostacyclin analog on pulmonary edema in isolated heart-lung autoperfusion model.

Pulmonary edema and impaired gas exchange function are worrisome early complications of heart-lung transplantation. The present study was designed to determine the effect of a new prostacyclin analog, OP-41483, on these complications with the use of a heart-lung autoperfusion model. Twenty-four mongrel puppies (4 to 6 kg) were evenly divided into four groups according to the oxygen content of inspired air (group 1, 95%; group 2, 60%) and the use of an intravenous drip of OP-41483 (0.1 microgram/kg/min) (group 3, 95% + OP; group 4, 60% + OP). During the course of these experiments, systolic pressure and cardiac output were maintained constant at 100 mm Hg and 40 ml/kg/min, respectively. Pulmonary arterial pressure was almost constant in each group throughout the experiment. Arterial oxygen tension (Pao2) was significantly decreased in groups 1 (410 +/- 49 to 237 +/- 38 mm Hg, p less than 0.01) and 2 (368 +/- 44 to 243 +/- 26 mm Hg, p less than 0.01) over the 5-hour autoperfusion period but was maintained at a high level in groups 3 (488 +/- 70 to 447 +/- 39 mm Hg) and 4 (431 +/- 33 to 430 +/- 35 mm Hg). Pathologic findings (perivascular edema and capillary dilatation) were significant in group 1 but less marked in group 2. However, no abnormal pathologic changes were observed in groups 3 or 4. These data demonstrated that OP-41483 was effective in preventing functional and pathologic pulmonary disturbances at a dosage (0.1 microgram/kg/min) that is reported to induce no undesirable hemodynamic effect.

Animals↗
PubMedDate not supplied

[Evaluation of the lumen-plaque-wall alterations by intravascular ultrasound imaging after percutaneous transluminal laser angioplasty in peripheral arteries: comparison with angiographic findings].

Intravascular ultrasound imaging was compared to angiography for evaluation of the changes in arterial lumen, atherosclerotic plaque and arterial walls after percutaneous transluminal laser angioplasty (PTLA) in peripheral arteries. Seventeen procedures using an argon laser angioplasty system (LASTAC system II) were performed in 13 patients with totally occluded lesions in the superficial femoral and iliac arteries. During or immediately after PTLA, a 30 MHz intravascular ultrasound catheter was inserted into the channel created by laser irradiation and adjunctive balloon dilatation. The outcome of PTLA was considered morphologically successful if the residual stenosis measured by intravascular ultrasound was 75% or less. Intravascular ultrasound showed eccentric plaques in 12 (71%), calcified plaques in 11 (65%), intraluminal thrombi in 2 (12%) and arterial wall injuries in 13 (76%) of the 17 lesions. PTLA was successful in 13 lesions and failed in 4. Occurrence of arterial dissections (38%) and mean residual stenoses (44 +/- 13%) were significantly (p < 0.05) lower in successful PTLA than in unsuccessful PTLA (100%, 89 +/- 3%). Eccentric stenoses, calcified plaques and arterial wall injuries were associated with poor success. Intravascular ultrasound detection of eccentric stenoses (71%), calcified plaques (65%) and arterial wall injuries (76%) was better than by angiography (29, 29, 47%). However, no significant correlation between intravascular ultrasound and angiographic findings could be found in quantitative estimation of the residual stenoses. Intraluminal thrombi were identified only by intravascular ultrasound. Angiography showed abnormalities in five (83%) of six lesions with medial injuries demonstrated by intravascular ultrasound, but none of the seven lesions with intimal injury. Intravascular ultrasound provides accurate diagnosis of eccentric stenosis, calcification, and arterial wall injury, and can quantitatively estimate residual stenosis and arterial wall injury during and immediately after PTLA in peripheral artery disease.

Aged↗
PubMedDate not supplied

Effects of intraaortic balloon pumping on portal venous flow. Assessment with color Doppler echography.

The effects of intraaortic balloon pumping (IABP) on portal venous flow were assessed using color Doppler echography. A total of 23 heart failure patients treated with IABP were assessed. Balloon inflation was timed to occur with every other cardiac contraction. The maximum, minimum, and mean flow velocity (Vmax, Vmin and Vmean, respectively) in the right portal vein were measured with the IABP ON and OFF, and the values compared. The Vmin with IABP ON and OFF was the same (11 +/- 5 cm/sec), whereas the difference between Vmax and Vmean was small for each patient. The velocities measured with IABP ON were larger than or equal to those with IABP OFF in all cases, however, except one. Thus, Vmax (22 +/- 8 cm/sec) and Vmean (17 +/- 6 cm/sec) with IABP ON were significantly larger (p 0.01) than those with IABP OFF (20 +/- 7 cm/sec and 16 +/- 6 cm/sec, respectively). The flow pattern of the portal vein was characteristically pulsatile either with IABP ON or OFF in most cases.

Adult↗