Search PubMed⌕ Search

Biomedical subjects

S Takamoto

Publications and source records attributed to S Takamoto.

At least 253 records · Page 14Linked to original sources
PubMed1987

Visualization of thoracic dissecting aortic aneurysm by transesophageal Doppler color flow mapping.

Real-time color flow mapping by two-dimensional Doppler has now come into widespread use. However, its application via conventional transcutaneous approaches to dissecting aortic aneurysm has some limitations where visualization of the descending aorta is concerned. Its transesophageal approach to this disorder has hitherto remained unreported except by the authors. Transesophageal Doppler color flow mapping has been performed in twelve patients for diagnosis of dissecting aortic aneurysm, and the clinical significance of this method was evaluated. The system used for transesophageal color flow mapping was an Aloka SSD-880 ultrasound scanner with a 5 MHz probe. In all cases, the entire thoracic aorta except for the upper ascending aorta was visualized and both, real-time flow dynamics and structural information, were ascertained. Differentiation of the type of dissection, identification of the entry, and differentiation of the true and false lumina were performed in all cases. Information concerning the reentry was gained in seven cases (58%); aortic regurgitation was graded in three cases, in two of which prolapse of the intimal flap was observed. In five cases, aortography was needed in order to delineate the involvement of aortic branches in the dissection; and in the other seven cases, transesophageal Doppler information was sufficient. In four cases who were operated, the postoperative state was well evaluated. Transesophageal Doppler color flow mapping was found to be a useful method for visualization of the whole thoracic aorta apart from the upper ascending section, and for precise evaluation of the structure and hemodynamics of dissecting aortic aneurysms.

Aortic Dissection↗
PubMed1987

Immediate and early postoperative evaluation of results of cardiac surgery by transesophageal two-dimensional Doppler echocardiography.

In cardiac surgery significant residual lesions increase postoperative morbidity and mortality. Although intraoperative epicardial real-time two-dimensional Doppler echocardiography (two-dimensional Doppler) is an accurate and efficient technique for assessing the presence and severity of a residual lesion, it requires placement of a transducer in the operating field and consequent obstruction of the operative procedure. Transesophageal two-dimensional Doppler echocardiography (transesophageal two-dimensional Doppler), which can be applied intraoperatively and postoperatively without such problems, was performed in 35 patients during cardiac surgery (12 patients) and/or at an intensive care unit within 6 hr after cardiac surgery (30 patients). In those with constrictive pericarditis, an extensive pericardiectomy was performed with effective monitoring by intraoperative transesophageal two-dimensional Doppler. Abnormal posterior wall motion was observed in the case of left ventricular rupture (type III) after mitral valve replacement 3 hr before clinical manifestation. After prosthetic valve replacement (18 St. Jude Medical valves, one Carpentier-Edwards valve, one Björk-Shiley valve), no perivalvular leakage was detected, but minor physiologic transvalvular leakage was noticed in 11 patients with St. Jude Medical valves. In two patients with congenital heart disease, a small residual shunt was detected. In a patient in which a composite valve graft with direct coronary artery reattachment (Bentall's operation) was performed, reattachment was confirmed to be satisfactory. In conclusion, intraoperative and early postoperative monitoring of cardiac function by transesophageal two-dimensional Doppler echocardiography can improve the results of cardiovascular surgery by providing accurate information on cardiovascular structure and blood flow dynamics.

Adult↗
PubMed1986

Effect of 1 alpha-hydroxycholecalciferol on psoriasis vulgaris: a pilot study.

We carried out a clinical trial of 1 alpha-hydroxycholecalciferol [1 alpha(OH)D3] at a dose of 1.0 microgram a day on 7 patients with psoriasis vulgaris. These patients had been treated by topical applications of corticosteroids before this study without improvement, and during the clinical trial, treatment of topical corticosteroids was continued on 6 of the 7 patients. Four of 7 patients showed complete remission and marked improvement and 2 additional patients showed minimal improvement of their skin lesions during and after the treatment with 1 alpha(OH)D3. No adverse reactions were noted during the treatment period. The mechanism of the phenomenon we observed has yet to be elucidated. Controlled trials of large numbers of patients with psoriasis vulgaris treated with 1 alpha(OH)D3 are under way.

Administration, Oral↗
PubMed1986

Analysis of cell surface molecules on human platelets with monoclonal antibodies. I. Identification of four platelet-specific surface molecules.

Eighteen monoclonal antibodies against human platelets were raised. Extensive serological analyses confirmed that all 18 antibodies reacted only with human cells of thrombocytic lineage. Four different molecules were identified by immunoprecipitation and SDS-PAGE analysis with these antibodies: GPIIb-IIIa as detected with the four antibodies HPL 1-4, GPIb with the twelve antibodies HPL 7-18, and two mutually distinct, newly defined molecules, gp 78 and p 151, were detected with the two remaining antibodies, HPL 5 and HPL 6, respectively.

Antibodies, Monoclonal↗
PubMed1986

Doppler ultrasound examination of prosthetic function and ventricular blood flow after mitral valve replacement.

Two-dimensional color Doppler echocardiography enables delineation of the spatial and temporal distribution of blood flow in the heart. In this study, the method was applied for investigation of flow dynamics in multiple planes in the region of prosthetic mitral valves for comparison with that of native mitral valves. In 15 healthy subjects there was normal flow toward the transducer, coded in red, in the left ventricle along the posterolateral wall (left ventricular inflow region) and blue-coded flow away from the transducer in the left ventricular outflow region during diastole. In 40 patients with St. Jude mitral valve prosthesis and 17 with bioprosthesis the flow pattern in the left ventricle was reversed. Mitral inflow was directed against the interventricular septum, accordingly, into the left ventricular outflow region while the outflow pattern was displaced posterolaterally into the left ventricular inflow region during diastole. The angle between the aortic valve ring and the mitral annulus was significantly smaller than in the healthy subjects. The angle between the central axis of the mitral prosthesis and the mitral inflow, which was 0 degrees in healthy subjects, was increased by the medial deviation in particular, in those with mechanical St. Jude prostheses. The maximal transprosthetic velocity, measured in 70 patients, and the maximal pressure gradient calculated according to the Bernoulli equation was substantially greater than the values in healthy subjects. In contrast to findings associated with normally-functioning prostheses, in four patients with prosthetic malfunction there was a diastolic peak velocity of more than 2 m/s as well as marked turbulence in the inflow region.

Bioprosthesis↗
PubMed1986

[Immediate surgical revascularization following unsuccessful coronary thrombolysis: effects on myocardial salvage].

To reduce early and late mortality and morbidity following acute myocardial infarction (AMI), myocardial salvage of the jeopardized areas by coronary thrombolysis (PTCR) during the acute period is effective. However, unsuccessful thrombolysis or severe residual coronary stenosis may result in severe cardiac failure and high mortality in the early and late periods. This study was undertaken to demonstrate the effects of immediate coronary artery bypass surgery (CAB) following unsuccessful PTCR. Thirty-three patients with initial AMI were studied, in whom PTCR was performed within 10 hours of onset of chest pain but it was unsuccessful. In 16 cases (Group I) total occlusion could not be recanalized, and in 17 cases (Group II) subtotal residual stenosis (99% with delayed flow on coronary angiogram) remained. The effects of immediate CAB surgery (Group I-b: 4 cases; Group II-b: 9 cases) for myocardial salvage were evaluated by thallium-201 scintigraphy one to 14 months after onset of AMI, as compared to medical therapy (Group I-a: 12 cases; Group II-a: 8 cases). The thallium uptake in the jeopardized area was categorized as (1) defect (+), (2) decrease, and (3) defect (-). All 12 cases in Group I-a showed defect (+). In Group I-b, one case showed defect (+), one case decreased, and two cases defect (-). In Group II-a, seven of eight cases (88%) showed defect (+) and one case showed decrease; however, in Group II-b seven of nine cases (78%) showed defect (-) and two cases showed defect (+). The effects on myocardial salvage were significantly different between Group a and Group b (p less than 0.001) and Group II-a and Group II-b (p less than 0.01). In conclusion, immediate CAB surgery was superior to medical therapy for ischemic myocardial salvage following unsuccessful PTCR. These results encourage the application of immediate postinfarction CAB surgery in high-risk groups with severe residual coronary stenosis after PTCR.

Aged↗
PubMed1986

[Visualization of coronary blood flow by transesophageal Doppler color flow mapping].

For noninvasive evaluation of coronary blood flow, 22 patients were examined with transesophageal Doppler color flow mapping within six hours after cardiovascular surgery. The anatomical structure of the left main coronary trunk (LMT) was observed by conventional two-dimensional echocardiography (2-DE) in 20 patients (91%), and color flow of the LMT was visualized in 18 of 21 patients (86%) (one patient had total occlusion). The blood flow in the LMT began in mid-systole, but the flow was observed mainly in diastole. The peak of the flow was observed mainly in late diastole and the range of the peak velocity was 35 to 163 cm/sec (average = 76.9 +/- 31.4 cm/sec). The proximal portion of the right coronary artery (RCA) was observed in 13 patients (59%), and its color flow was visualized in only two patients (9%). In two patients intra-aortic balloon pumping (IABP) assist was performed postoperatively, and the direct effect of the assist on the coronary blood flow was clearly observed by transesophageal Doppler color flow mapping. The peak blood flow velocity of the LMT increased by 32% during the assist. In conclusion, human coronary blood flow can be visualized and evaluated noninvasively using transesophageal Doppler color flow mapping. This technique can be used for future investigation of coronary circulation.

Adult↗
PubMed1986

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

THP-adriamycin (THP) is a new derivative of adriamycin (ADM) which is reported to have a lower cardiotoxicity than ADM. In this report, the effects of THP on cell growth, cell cycle traverse and colony-forming ability of RPMI-8402 cells were investigated in comparison with ADM. The growth-inhibitory effect of THP was equal or superior to that of ADM in this system. Analysis of the DNA histogram obtained by flow cytometry showed that THP exerted its growth-inhibitory effect by blocking cells at the G2 phase. At higher concentrations, THP inhibited the traverse of cells through the S phase and further through the whole cell cycle completely. These effects were quite similar to those of ADM, which suggested a similar mechanism of action for the two drugs from the aspect of the cell cycle. A follow-up study of cells accumulated at the G2 phase and a study on colony-forming ability revealed that the G2 phase accumulation was an irreversible and fatal effect of THP, so that G2-phase accumulation could be considered as a cytocidal effect of THP, indicating the clinical usefulness of this system for evaluation of the drug effect. From these results and the low cardiotoxicity, it was suggested that THP could be a good candidate for use as an antitumor agent in clinics.

Cell Cycle↗
PubMed1986

[Antitumor effect of 1,3,3,5,5-pentaziridino-1-thia-2,4,6-triaza-3,5- diphoshorine-1-oxide].

The antitumor activity of 1.3.3.5.5-pentaziridino-1-thia-2.4.6-triaza-3.5-diphospho rine-1-oxide (SOAz) was investigated in vitro and in vivo. The results obtained were as follows: SOAz showed marginal cytotoxicity against growth of L1210 cells cultured in vitro. In the cell-cycle traverse of RPMI 8402 cells, SOAz prolonged the duration of the S phase, leading to the eventual accumulation of cells at the G2 phase. At the highest concentration, SOAz stopped the cell cycle progression completely. SOAz was found to have similar activity to carbazilquinone, cyclophosphamide or mitomycin C on P388 leukemia. SOAz showed marked antitumor effect against early-stage L1210 leukemia, and was also effective against advanced-stage L1210 leukemia. The therapeutic efficacy of SOAz depends on the treatment schedule. Single injection and intermittent treatment were superior to daily treatment. Oral administration of SOAz was effective as well as i.p., i.v. and i.m. administration.

Animals↗
PubMed1985

Assignment of gene coding human T-cell differentiation antigen, Tp120, to chromosome 11.

A pan T-cell antigen with a molecular weight of 120 kilodaltons (kd) is recognized by a monoclonal antibody, Tp120, produced in our laboratories. Two hybrid clones reactive with this Tp120 antibody were established from the fusion between concanavalin A-stimulated human peripheral blood lymphocytes and hypoxanthine-guanine phosphoribosyltransferase-deficient mouse T cell leukemia, BW5147. These two clones were also positive with two other antibodies, 12.1 and T12, both of which detect 120kd pan T-cell antigen. Karyotype analysis showed that one clone retained human chromosomes 6, 7pq-, and 11, and the other maintained chromosomes 11 and 21. As soon as both of these clones lost the chromosome 11, the expression of Tp120 became negative. The presence of human chromosome 11 was confirmed by the isozyme analysis of lactate dehydrogenase-A. The results indicated that the presence of chromosome 11 was essential for expression of 120kd pan T-cell antigen.

Animals↗
PubMed1985

Comparison of renal responses to synthetic human PTH(1-34) administration in normal young and elderly male subjects.

A parathyroid hormone (PTH) loading test with synthetic human PTH(1-34) was performed in 7 young and 6 elderly normal males. The elderly subjects had significantly higher mean basal levels of serum PTH than the young subjects (0.262 +/- 0.035(SE) vs 0.097 +/- 0.012 ng Eq/ml, P less than 0.001). When human PTH(1-34) at a dose of 100 U was administered to these subjects, the mean increases in urinary excretions of adenosine cyclic 3',5'-monophosphate(cAMP) and inorganic phosphorus (Pi), expressed as increases in absolute amounts per unit time, were significantly lower in the elderly subjects. (3.65 +/- 1.02 vs 7.41 +/- 1.05 mumol/h, P less than 0.05 for cAMP and 14.7 +/- 6.3 vs 41.8 +/- 8.6 mg/2h, P less than 0.05 for Pi) and an inverse correlation was found between the serum PTH levels and the increases in urinary cAMP excretion (mumol/hr; r = -0.63, P less than 0.05). However, when corrected for the glomerular filtration rate (GFR) and the units of PTH administered per kg body weight, the increases were not significantly different in the two groups (elderly 52.1 +/- 7.5 vs young 60.0 +/- 19.2 nmol . kg/100 ml GFR . U . h for cAMP and 0.315 +/- 0.061 vs 0.186 +/- 0.044 mg . kg/100 ml GFR . U . 2 h respectively for Pi).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Serum phosphate, parathyroid hormone and vitamin D metabolites in patients with chronic renal failure: effect of aluminum hydroxide administration.

Patients with chronic renal failure showed the existence of phosphate retention, secondary hyperparathyroidism, and reduced production of 1,25-(OH)2D. In order to determine the effect of correction of hyperphosphatemia on secondary hyperparathyroidism and vitamin D metabolism in those patients, 7 nondialyzed patients with chronic renal failure were treated with large doses of A1(OH)3 (15-18 g/day) to correct their high levels of serum phosphate. After treatment with A1(OH)3, serum phosphate fell significantly (p less than 0.005) from 6.3 +/- 1.3 (mean +/- SD) to 3.7 +/- 0.5 mg/dl. Serum parathyroid hormone decreased significantly (p less than 0.02) from 2.87 +/- 1.64 to 1.85 +/- 1.26 ngEq/ml. Serum 1,25-(OH)2D was low compared to the normal mean level before A1(OH)3 administration and decreased significantly (p greater than 0.02) from 19.4 +/- 6.1 to 11.4 +/- 4.3 pg/ml after the treatment. Aluminum levels increased significantly (p greater than 0.02) from 1.7 +/- 1.0 to 3.6 +/- 1.5 micrograms/dl. Serum calcium, calcitonin, and 25-(OH)D showed no significant change. Our data suggested that the suppression of secondary hyperparathyroidism by A1(OH)3 treatment results in a decrease of the 1,25-(OH)2D level in patients with chronic renal failure, even though their hyperphosphatemia has been corrected. We speculate that aluminum loading might play a role in diminishing the secretion of parathyroid hormone and the production of 1,25-(OH)2D in humans.

Adult↗
PubMed1985

Prolactin secretion in acromegalic patients before and after selective adenomectomy.

PRL secretion before and after transsphenoidal adenomectomy was studied in 13 patients with acromegaly. Six patient had elevated basal serum PRL levels before surgery, while 7 patients had normal levels. In every patient, the basal serum GH level decreased to less than 5.0 ng/ml after surgery. In the group (group A) with high basal serum PRL levels (mean +/- SD, 41.3 +/- 5.8 ng/ml) before surgery, the PRL levels decreased significantly (P less than 0.0002) to less than 10.0 ng/ml (4.8 +/- 3.6 ng/ml) after the operation. However, in the group (group B) with normal levels (10.8 +/- 4.4 ng/ml) before surgery, PRL levels changed little (7.8 +/- 3.1 ng/ml) after the operation. In group A, the increment of PRL after TRH injection decreased or disappeared (P less than 0.02; 4.1 +/- 2.4 ng/ml) after surgery compared with that before surgery (39.2 +/- 25.9 ng/ml). On the other hand, in group B, the increment of PRL after TRH injection was nearly unchanged (17.1 +/- 7.0 ng/ml) after surgery compared with that before surgery (19.3 +/- 8.0 ng/ml). The results indicate that PRL is secreted from the pituitary adenoma in acromegalic patients with hyperprolactinemia, while PRL secretion from the normal part of the pituitary gland is decreased.

Acromegaly↗
PubMed1985

Changes in calcium homeostasis in acromegaly treated by pituitary adenomectomy.

Patients with acromegaly have alterations in mineral metabolism. To determine the effect of correction of excess GH secretion on calcium metabolism, we studied 12 acromegalic patients before and 3-4 weeks after pituitary adenomectomy. Treatment of acromegaly resulted in significant decreases in both serum calcium [from 9.3 +/- 0.2 to 8.7 +/- 0.1 mg/dl (mean +/- SEM); P less than 0.01] and urinary calcium excretion (from 200 +/- 24 to 88 +/- 12 mg/24 h; P less than 0.0002). Serum phosphate also decreased significantly (P less than 0.01) from 4.8 +/- 0.2 to 4.3 +/- 0.2 mg/dl. Both serum immunoreactive PTH and calcitonin levels were normal initially and did not change after surgery. The mean serum 25-hydroxyvitamin D (25OHD) level was significantly (P less than 0.01) lower and the 1,25-dihydroxyvitamin D [1,25-(OH)2D] level was significantly (P less than 0.0001) higher in acromegaly compared with measurements in 25 normal subjects. After surgery, the serum 25OHD level did not change; however, the serum 1,25-(OH)2D concentration fell significantly (P less than 0.0001) from 60 +/- 4 to 43 +/- 2 pg/ml. A positive correlation was found between the decrements in urinary calcium excretion and the serum 1,25-(OH)2D level when the comparison was made between the decrements as percentages of pretreatment values (r = 0.64; P less than 0.05). The accumulated data suggest that the hypercalciuria in acromegaly might be due to intestinal calcium hyperabsorption, which could be attributed to the elevated circulating 1,25-(OH)2D level. Excessive GH secretion might stimulate the production of 1,25-(OH)2D and might also directly stimulate calcium absorption.

Acromegaly↗
PubMed1985

An acromegalic patient with recurrent urolithiasis.

A 52-year-old man with an acromegalic appearance of prolonged duration suffered abdominal colic attacks and hematuria during the middle of the course of the disease. The patient was diagnosed as having urolithiasis caused by increased urinary calcium. The calcium metabolic disorder was not considered to be due to hyperparathyroidism because serum calcium and PTH levels were within the normal range and no abnormality was observed in a parathyroidal scintigraph. The serum 1,25-dihydroxyvitamin D (1,25-(OH)2D) levels (55.0 and 73.0 pg/ml) were higher than the normal range (27.2-53.8 pg/ml). A selective adenomectomy by the transsphenoidal route (Hardy's method) was performed, resulting in an improvement in the hypercalciuria and urolithiasis, and a decrease in the levels of serum 1,25-(OH)2D (23.0 and 23.0 pg/ml). These findings suggest that GH may promote the activation of vitamin D in the kidney in acromegaly, resulting in an acceleration of calcium absorption in the intestine through the action of activated vitamin D and the induction of increased urinary calcium excretion by the urinary excretion of excessive blood calcium.

Acromegaly↗