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Biomedical subjects

S Takamoto

Publications and source records attributed to S Takamoto.

At least 217 records · Page 12Linked to original sources
PubMed1992

[Flow cytometric analysis of the effect of DWA2114R on the cell cycle traverse of RPMI 8402 cells--comparison with CDDP].

The (-) - (R) - 2-aminomethylpyrrolidine (1, 1-cyclobutanedicarboxylato) platinum(II) monohydrate, DW A2114R, is a new derivative of cis-dichlorodiammineplatinum(II), CDDP, which is reported to have a lower nephrotoxicity than CDDP. In this report, we investigated the effects of DW A2114R, in comparison with CDDP, on the cell growth, the cell cycle traverse and the colony-forming ability of human leukemia RPMI 8402 cells in vitro. The inhibitory effects of DW A2114R on the cell growth and the colony-forming ability were about 1/10 and 1/10-1/30, respectively, of the CDDP dose. And DW A2114R showed a higher time-dependency than CDDP in the experiment comparing exposure time to the drugs. Analysis of DNA histograms obtained by flow cytometry revealed that DW A2114R had a similar effect on the cell cycle traverse to that of CDDP. Both drugs exerted their growth-inhibitory effect by blocking cells at G2 phase. At higher concentrations, they prolonged the traverse of cells through S phase and completely inhibited them throughout the cell cycle. The comparative study on the colony-forming ability suggested that the G2 phase accumulation was irreversible and that these drugs are lethal, so the G2 phase accumulation could be considered a cytocidal effect of the drugs. In early clinical studies, however, the dose of DW A2114R was put at about 15-fold higher than the therapeutic dose of CDDP. This was comparable with our results in vitro and DW A2114R showed a much lower toxicities, with special regard to nephrotoxicity, than CD DP. These clinical data and our results suggest that DW A2114R could be clinically effective as an antitumor agent.

Antineoplastic Agents↗
PubMed1992

[Efficacy of leukocyte-depleted platelet concentrates for prevention of HLA-alloimmunization in patients with frequent platelet transfusions: a prospective multi-institutional study using a polyester platelet filter].

A prospective multi-institutional study was conducted to assess the efficacy of leukocyte-depleted platelet concentrates, prepared by a method using a newly developed polyester filter, in the prevention of HLA-alloimmunization in patients with hematological disorders. Patients who were expected frequent platelet transfusions, were assigned into two groups, receiving either standard platelet concentrates (control group) or leukocyte-depleted platelet concentrates prepared through a polyester platelet filter, Sepacell-PL (filtered group). All patients received leukocyte-depleted red cell products. Of III patients enrolled, 72 were evaluable, 23 in the control and 49 in the filtered group. Both groups were comparable according to age, sex ratio, underlying disorders, previous exposure to alloantigens by transfusion and/or pregnancy. There was no statistically significant difference in the number and duration of transfusion in the two groups. There were significant differences in HLA-alloimmunization rate (9 cases out of 23, 39% in the control group versus 4 cases out of 49, 8% in the filtered group; p less than 0.01) and refractoriness to platelet transfusion from random donors (6 cases out of 23, 26% in the control group versus 2 cases out of 49, 4% in the filtered group; p less than 0.05). These results indicated that leukocyte-depleted platelet concentrates prepared through the polyester platelet filter are beneficial to reduce HLA-alloimmunization in patients with frequent platelet transfusions.

Adolescent↗
PubMed1992

[Simple hypothermic retrograde cerebral perfusion for brain protection during aortic arch surgery].

We have recently found that retrograde cerebral perfusion can be performed by simply elevating central venous pressure to 15 mmHg in the Trendelenburg position when the aortic arch is open during aortic arch surgery. During deep hypothermic (15 degrees C) perfusion of the lower half of the body with the descending aorta occluded, and with single cannulation of the right atrium for drainage, oxygen-saturated venous blood perfuses the brain retrogradely, supplying it with oxygen. This method renders clamping of the aortic arch and the arch vessels unnecessary. Eleven cases of aortic arch aneurysm (9 males, 2 females; 5 true aneurysms, 5 dissecting aneurysms, one combined aneurysm; mean age, 63 years) were operated using this technique, whose clinical significance was then evaluated. Median sternotomy was performed in 4 cases, left thoracotomy in 7. Patch replacement was performed in 2 cases and graft replacement in 9 cases (the proximal arch in 2, the whole arch in 2, the distal arch in 5). In two cases coronary artery bypass surgery using the internal thoracic artery was performed simultaneously via lateral thoracotomy. Operation time was 517 +/- 139 min, pump time was 211 +/- 34 min, cardiac arrest time was 84 +/- 34 min and the lowest rectal temperature was 15.7 +/- 1.1 degrees C. In the venous return, PO2 was 188 +/- 136 mmHg, and SO2 97.5 +/- 2.9%, the respective values in the retrogradely perfused blood in the aortic arch being 46 +/- 12 mmHg and 68.8 +/- 18.8%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Alterations of duodenal vitamin D-dependent calcium-binding protein content and calcium uptake in brush border membrane vesicles in aged Wistar rats: role of 1,25-dihydroxyvitamin D3.

Previously we reported that uptake of Ca2+ in cells isolated from rat duodenum declined in senescence. In this paper we examined the possible mechanisms for this age-related defect. Duodenal vitamin D-dependent calcium-binding protein decreased steadily from 3-12 months (mo), followed by a minimal decline at 24 mo. On the contrary, Ca2+ uptake was not different in 3-, 6-, and 12-mo-old rats. A significant decline of Ca2+ uptake was observed at 24 mo. ATP contents in duodenal cells from 6- and 24-mo-old rats were not different. This suggests that the metabolic status of the duodenal cells was not the cause of the change in Ca2+ uptake. Ca2+ uptake activity was significantly lower in brush border membrane vesicles isolated from 24-mo-old rats than in those from 6-mo-old rats. The decrease in Ca2+ uptake activity in old rats was not due to a change in the Ca2(+)-binding capacity of the membranes. Kinetic analysis shows that the Vmax, the apparent maximum uptake capacity of membrane vesicles, decreased in senescent rats, whereas the Km, the apparent affinity to Ca2+, was unchanged. Since duodenal Ca2+ influx at the brush border was regulated by 1,25-dihydroxy-vitamin D3 [1,25-(OH)2D3], we tested the effect of 1,25-(OH)2D3 administration on the uptake activity in isolated membrane vesicles. After 1,25-(OH)2D3 treatment, Ca2+ uptake activity in brush border membranes prepared from senescent rats was only slightly lower than that in membranes from adult rats. We conclude that the decline in the influx of Ca2+ at the brush border membrane was the main cause of the decrease in duodenal Ca2+ uptake activity in aging. This defect was probably due to the low serum 1,25-(OH)2D3 concentration and not the result of impaired response to 1,25-(OH)2D3.

Adenosine Triphosphate↗
PubMed1991

[An elderly case of systemic lupus erythematosus associated with herpes zoster, anemia, and hemiparesis].

An elderly case of systemic lupus erythematosus (SLE) with suspected hemolytic anemia was experienced. A 70 year-old female was admitted to our hospital on December 31 with complaints of herpetic eruption. She complained of arthralgia since 3 month prior to her admission. The positive findings on examination were skin eruption in the left chest, a systolic heart murmur and a palpable elastic hard liver. Laboratory data showed raised erythrocyte sedimentation rate of 149 mm per hour, decreased Hb (10.1 g/dl), decreased hematocrit (30.0%), increased reticulocytes (33%1000), decreased thrombocytes (73,000/mm3), increased gamma-globulin (33%) and positive rheumatoid factor. During admission, she developed anemia. A stool test for occult blood was negative. The haptoglobin was 38.8 mg/dl and bone marrow aspiration showed increased erythropoiesis, suggesting features of immune hemolytic anemia, except she was negative on Coomb'test. Eye fundi were similar to case of typical bleeding observed in SLE. Concerning immunological findings, the antinuclear factor was x 1280 and the anti-dsDNA antibody was x 80, on which a diagnosis of SLE was based. She experienced numbness of the left arm and developed left hemiparesis 2 days later. Therapy with 15 mg/day prednisone obtained a good response and anemia, abnormal immunological findings and hemiparesis disappeared.

Aged↗
PubMed1991

[Diagnosis of acute aortic dissection with transesophageal echocardiography and results of surgical treatment].

Forty-four consecutive patients with acute aortic dissection from April 1987 to April 1990 were diagnosed with the use of transesophageal echocardiography (TEE) and treated at our institute. In 43 of them (98%, type A: 22 cases, type B: 21 cases), diagnosis was accurate and there were no complications. In one patient with type A dissection, the small intimal flap could not be detected. Emergency operations were performed in the patient with type A and ruptured type B. In type A, operated before cardiac arrest, the operative mortality rate was 20% (4/20). In ruptured type B, the operative mortality rate was 50% (2/4). The result of conservative therapy in the patient with nonruptured type B (17 cases) was satisfactory. The investigation by TEE was carried out without difficulty at the bed side and in the operating room as well, giving precise and rapid information and could be a useful diagnostic mean for acute aortic dissection.

Acute Disease↗
PubMed1991

[Evaluation of tumor vascularization in primary lung cancer by transesophageal color Doppler echography].

A 63 year-old male with primary lung cancer, was examined by transesophageal color Doppler echography (TEE). TEE revealed metastatic lymph node adjacent to the root of the right pulmonary vein. Direct invasion to the left atrium was neglected because of the finding that the left atrial wall was fluctuating according to cardiac movements. TEE also visualized a tumor vessel in which peak velocity of the flow was high, 1m/sec. The resected specimen showed that the tumor vessel had originated from the bronchial artery in the metastatic lymphnode. High velocity flow in the tumor by transesophageal Doppler analysis is highly indicative of malignancy. Doppler analysis in the tumor vessel might be useful in tissue characterization of the lymphnode in primary lung cancer.

Carcinoma, Squamous Cell↗
PubMed1991

Emergency surgical intervention of acute aortic dissection with the rapid diagnosis by transesophageal echocardiography.

Forty-five serial patients with acute aortic dissection were examined by transesophageal color Doppler echocardiography (TEE), and the diagnosis was made without aortography. No complications related to TEE occurred. Sufficient information for surgery was immediately obtained at the bedside by the TEE examination. Forty-four of 45 patients (98%) were diagnosed accurately, and 20 emergency operations for patients with type A aortic dissection and six emergency operations for patients with type B aortic dissection were performed. In only one patient, a small intimal flap in the ascending aorta was not detected by TEE. The operative mortality rate was 20% and 50% for types A and B aortic dissections, respectively. As a result of the progress of biplanar TEE technology, an easier and more accurate diagnosis of patients with acute aortic dissection can be achieved. The immediate and accurate diagnosis of acute aortic dissection can be achieved by TEE at the bedside, and treatment strategy can be more precisely determined.

Adult↗
PubMed1991

[Aortic arch replacement by simple hypothermic retrograde cerebral perfusion for long cerebral circulatory arrest--a successful case report].

We have recently discovered that hypothermic cerebral retrograde perfusion can be performed by simply elevating the central venous pressure in Trendelenburg's position during aortic arch surgery. During deep hypothermic perfusion of the lower half of the body with an occlusion balloon in the descending aorta, oxygen saturated venous blood supplied the brain with oxygen. A successful case is reported. A case was 53 y.o. woman of dissecting aortic aneurysm DeBakey type II, with a true aortic arch aneurysm. Under median sternotomy the right atrium and the femoral artery were cannulated for cardiopulmonary bypass. With the brain under retrograde perfusion at a rectal temperature of 16 degrees C and a central venous pressure of 10-15 mmHg, the ascending to the descending aorta was replaced. Blood flowed into the aortic arch from the arch vessels was blackish in color. Brain circulatory arrest time was 81 min. Postoperative course was uneventful. It is suggested that this simple retrograde cerebral perfusion during hypothermic aortic arch surgery protected the brain for an extended brain circulatory arrest time, and eliminated the need for clamping at the aortic arch and the arch vessels, and simplified the operative procedure.

Aortic Dissection↗
PubMed1990

[Case report of a patient with pseudohypoparathyroidism associated with slight increase in serum level of unconjugated bilirubin].

We treated a 29-year-old male patient with pseudohypoparathyroidism type I, who showed a slight increase in serum indirect bilirubin without any signs of liver dysfunction. Serum levels of total, direct and indirect bilirubins were 2.4, 0.7 and 1.7mg/dl, respectively (normal ranges: 0.2-0.8, 0-0.2 and 0.2-0.6mg/dl, respectively). The cause of the increases in serum bilirubin levels was not clear; however, hemolytic anemia, hereditary unconjugated hyperbilirubinemia or ineffective erythropoiesis were ruled out as causes for the increase, since 1) his serum level of haptoglobin was normal, 2) increase in serum level of indirect bilirubin 120 minutes after the infusion of 50mg nicotinic acid was within the normal range, and 3) severe anemia was not observed. Osmotic fragility of his circulating red blood cells was also within normal range. Three other patients with pseudohypoparathyroidism visiting our clinic also showed slightly high levels of serum indirect bilirubin, although four outpatients with idiopathic hypoparathyroidism showed no such abnormality. Abnormality in the responsiveness to parathyroid hormone and/or to that in the cyclic AMP productivity in this disease may cause the increase in the circulating unconjugated bilirubin.

Adult↗
PubMed1990

Effect of age on duodenal 1,25-dihydroxyvitamin D-3 receptors in Wistar rats.

We confirmed our previous observation that duodenal Ca2+ absorption and serum 1,25-dihydroxyvitamin D (1,25-(OH)2D) levels declined concurrently in old (24 months old) rats as compared to young (6 months old) rats. It is well known that 1,25-dihydroxyvitamin D-3 (1,25-(OH)2D3) expresses its action after binding to specific receptor molecules. In this paper, we compared certain properties of rat duodenal 1,25-(OH)2D3 receptors from old and young animals. Receptor preparations were incubated with [3H]1,25-(OH)2D3 to quantitate the number of unoccupied and total receptor sites and showed that total and unoccupied receptor sites decreased by 22 and 16%, respectively in old rats. Endogenously occupied sites were reduced by 43% in duodenum of the old rat and, consequently, the percentage of receptor occupancy also declined. Age did not affect the dissociation constant (KD) of 1,25-(OH)2D3 from the receptor; the sedimentation coefficient (3.3 S) of the tritiated 1,25-(OH)2D3-receptor complex in sucrose density centrifugation; or its affinity for DNA. The data are consistent with the hypothesis that the age-related decline in Ca2+ absorption in the intestine may be due, in part, to the decrement in the circulating level of 1,25-(OH)2D and a reduction of intestinal 1,25-(OH)2D3 receptor occupancy status.

Aging↗
PubMed1990

Effects of 1,25-dihydroxyvitamin D3 on the syntheses of DNA and glycosaminoglycans by rat aortic smooth muscle cells in vitro.

Studies were made on the effects of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] on the syntheses of DNA and glycosaminoglycans (GAG) by rat aortic smooth muscle cells (SMC) in vitro. DNA synthesis in cell cultures without fetal calf serum (FCS) was stimulated by incubation for 24 hr with 1,25-(OH)2D3 at concentrations of more than 10(-12) M, stimulation being maximal at a concentration of 10(-8) M. On the other hand, GAG synthesis was inhibited dose-dependently by 1,25-(OH)2D3 at concentrations of more than 10(-11) M. Other vitamin D3 metabolites had similar, but weaker effects on the syntheses of DNA and GAG by SMC, which were proportional to their affinities for the 1,25-(OH)2D3 receptor. These effects of 1,25-(OH)2D3 were not seen after short-term incubation (1 hr). These findings suggested that 1,25-(OH)2D3 stimulated the proliferation of SMC independent of growth factors in FCS, and that its effects were dependent on its specific receptor. Excess 1,25-(OH)2D3 might cause arteriosclerosis not only by stimulating proliferation but also by suppressing GAG synthesis.

Animals↗
PubMed1990

Comparison of the production of cyclic AMP in response to parathyroid hormone in fibroblasts from aged subjects and young subjects: lack of an age-dependent decrease.

An age-dependent effect on the ability to produce cyclic AMP in response to parathyroid hormone (PTH) stimulation was examined using culture skin fibroblasts from both young and elderly female subjects. The mean values of both absolute and comparative production of intracellular cyclic AMP due to various concentrations of PTH administration did not differ between the two age groups, although the mean serum PTH level was significantly higher in the elderly subjects. These results indicate that the decreased response of the target organ to PTH in aged subjects can be explained mainly by the decreased number of intact cells rather than a decreased response of individual cells to PTH.

Adolescent↗
PubMed1990

Primary structure of rat monoamine oxidase A deduced from cDNA and its expression in rat tissues.

The cDNA for rat monoamine oxidase A (MAO-A) mRNA was isolated from a liver cDNA library in lambda gt11 as the cDNA species cross-hybridizing with rat monoamine oxidase B (MAO-B) cDNA. The primary structure of the protein, deduced from the nucleotide sequence, consisted of 526 amino acid residues and its molecular mass was calculated to be 59.6 kD. The amino acid sequence shows about 70% identity with that of rat MAO-B. Northern blot analysis showed that MAO-B mRNA was expressed in various rat tissues and the highest expression was observed in heart. The MAO-B mRNA was quite different from MAO-A mRNA in the tissue-specific expression and liver had the highest level of the mRNA.

Amino Acid Sequence↗
PubMed1990

[Evaluation of patency of internal mammary artery grafts: a comparison of two-dimensional Doppler echocardiography with coronary angiography].

To examine the clinical feasibility of color flow mapping Doppler echocardiography (CFM) in diagnosing the patency of internal mammary artery (IMA) grafts, 41 patients who had had coronary bypass surgery were examined by both CFM and coronary angiography (CAG) within one week of the CFM examination. Coronary bypass surgery was performed one to eight months prior to this study, and the average number of bypass grafts was 2.7 +/- 0.7. The patency of the IMA grafts was confirmed in all except one patient by CAG; whereas, the flow in the IMA grafts was clearly visualized in all 22 patients by CFM from the left parasternal echo window. Peak velocities of the IMA graft flow in the 22 patients were 31.7 +/- 12.0 (19-49) cm/sec in diastole and 14.9 +/- 8.5 (5-36) cm/sec in systole. No false positive diagnosis was made in the CFM examination. The sensitivity, specificity, negative predictive value, and positive predictive value of CFM in the diagnosis of IMA graft patency were 55%, 100%, 5.3% and 100% respectively. In conclusion, although the sensitivity of color Doppler still remains relatively low, its specificity in the diagnosis of IMA graft patency is 100%. Thus, color Doppler is expected to be valuable for long-term follow-up of IMA graft patencies.

Adult↗
PubMed1990

[Advantages of transesophageal color Doppler echocardiography in the diagnosis and surgical treatment of cardiac masses].

To determine the clinical advantages of transesophageal color Doppler echocardiography (TEE) for imaging cardiac tumors and left atrial thrombi, 24 cases with intra- or extracardiac masses were examined by transthoracic color Doppler echocardiography (TTE) and TEE before and after cardiac surgery. Five with left atrial myxomas, two with lung tumors, five with mediastinal tumors and 12 with mitral stenosis coexisting left atrial thrombi were included in this study. The echocardiographic findings of the cardiac masses were compared with the surgical findings in all cases. In all of the five cases with left atrial myxomas, the tumors were detected. However, the sites of attachment and a stalk in three cases were not observed by TTE. TEE clearly imaged the left atrial myxomas, and evaluated the size and shape of the tumors, the sites of their attachment and a stalk arising from the interatrial septum, and mobility in four cases, except for one in which there was a broad attachment to the endocardium. Mitral regurgitation was detected in only two cases using the color Doppler mode of TTE, but in all cases using TEE. Both techniques failed to recognize tissue characterization. Among seven cases with secondary cardiac tumors or mediastinal tumors, extracardiac masses were detected in five; however, an intracardiac tumor attached to the interatrial septum and an extracardiac tumor extending to the superior vena cava and an upper part of the right atrium could not be imaged using TTE. TEE detected all tumors at all sites in the heart and vessels, and estimates of their extents were in accord with the operative findings in 17 of 18 sites. One exceptional case had a tumor which extended to the right ventricle. Neither technique could detect infiltration of the heart which was present in five of the seven cases. Multiple left atrial thrombi were observed in eight of 12 cases, resulting in 21 thrombi and they were diagnosed by TEE in six of 12 cases. Thrombi, when attached to the left atrial posterior or inferior walls, were easily detected in four of five cases, but were not identified in four of six and in eight of nine cases at the lateral wall or in the left atrial appendage by TTE. However, TEE detected all thrombi in every site in the left atrium and left atrial appendage in 11 of 12 cases. TEE was thus superior to TTE in detecting cardiac masses, recognizing abnormal flow and estimating anatomical relationship between tumors or thrombi and cardiac structures.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

[Analysis of DNA aneuploidy as a tumor marker].

DNA aneuploidy (DA) was examined in adult leukemia using flow cytometry, and the method and the clinical implication of DA as a tumor marker were evaluated. The method was simple, rapid, objective, quantitative and further did not need any mitotic cells, so was proved to be very useful for screening of DA. While, DA was detected in 50 (27%) out of 185 adult cases with various types of leukemia. The frequencies of DA in the subtypes of leukemia were 55% in ATL, 26% in ALL, 17% in ANLL, 26% in CML-BC and 6% in CLL, respectively. When compared with other subtypes, the frequency in ATL was significantly higher (p less than 0.01), which suggested a special entity of this disease. In general, however, the frequency of DA in leukemia was rather low, which indicated the difficulty in application of DA by itself in diagnosis of leukemia. While, in cases with DA, DA was very useful as a tumor marker in monitoring the clinical course, for example, in the detection of early relapse or recruitment of leukemic cells. Furthermore, DA was found to be a good prognostic factor which indicates a poor prognosis in cases with ANLL and CML-BC.

Adult↗