PubMed Health⌕ Search

Biomedical subjects

N Asada

Publications and source records attributed to N Asada.

At least 55 records · Page 3Linked to original sources
PubMed1987

Left ventricular image processing.

Left ventricular image processing methods of x-ray cineangiocardiograms and ultrasound echocardiograms are discussed. 3-D reconstruction methods of the left ventricle from ultrasound echocardiograms and magnetic resonance images are also discussed. Boundary detection of the left ventricle and the quantitative analysis of the left ventricular function and wall motion are discussed. To reconstruct 3-D shapes, we need several cross sectional shapes or silhouettes of the left ventricle. Several cross sectional echo images of apical long axis view are taken by changing the angles of rotation of the probe of echo transducer around its axis. Gated multi-phase MRI method is used to obtain each 2 cross sectional images in transverse, coronal and sagittal directions. Some results of 3-D shapes of the left ventricle and myocardium reconstructed are shown and 3-D functional images which give us regional functions of the left ventricular wall on three dimensional shape are shown.

Cineangiography↗
PubMed1985

Influence of pH change on redox state and CCK-induced secretion in isolated perfused rat pancreas.

The isolated perfused rat pancreas was used to examine the influence of the acid-base status of the perfusing solution on the redox states of cytochromes and secretory responses. Lowering the pH in a perfusing solution (pHe) from 7.3 to 6.8 induced simultaneous oxidation of cytochromes aa3, b, and c + c1, and further lowering to 6.0 induced larger oxidation of the cytochromes. Raising the pHe from 7.3 to 8.0 induced reduction of the cytochromes. Continuous stimulation with synthetic C-terminal octapeptide of cholecystokinin (CCK-8) at 100 pM induced the maximum secretory responses (pancreatic juice flow, protein output, and amylase output) during perfusion with the standard solution. The responses were not inhibited at pHe 6.8 but were inhibited significantly at pHe 6.0 or 8.0. The responses induced by stimulation with 20 pM CCK-8 were completely inhibited when pHe was lowered to 6.0 and CaCl2 was removed from the perfusing solution.

Adenosine Triphosphate↗
PubMed1985

Production of the modified form of human plasminogen by alpha 2-macroglobulin-plasmin complexes.

It has been speculated that the modified form of plasminogen, a precursor of proteolytic enzyme plasmin in plasma, plays an important role in fibrinolysis in the blood. The present study was undertaken to examine the production by alpha 2-macroglobulin-plasmin complexes. alpha 2-Macroglobulin-plasmin complexes were purified from urokinase-activated plasma by affinity chromatography on lysine-Sepharose and gel filtration on Ultrogel AcA 22. The plasmin complex converted native plasminogen into the modified form more easily in the presence of epsilon-aminocaproic acid. The modification of native plasminogen by alpha 2-macroglobulin-bound plasmin was completely inhibited by aprotinin, and partly by soybean trypsin inhibitor. alpha 2-macroglobulin-bound plasmin produced modified plasminogen in human plasma where potent plasmin inhibitors exist, though the degree of production was small. The present results support the speculation of the important role of the modified form in vivo.

Animals↗
PubMedDate not supplied

Deleterious effect of null phenoloxidase mutation on the survival rate in Drosophila melanogaster.

The effect of null activity of phenoloxidase on the survival rate was investigated in mutants of Drosophila melanogaster. MoxGM95 and Dox-3KD95, structural genes for prophenoloxidase A1 and A3, were found in natural populations in the former Soviet Union, and affected the phenoloxidase activity in active A1 or A3, respectively. After linking the visible markers located on the second chromosome together with the variants, cross experiments were performed to make homozygote, rdo Dox-3KD95 pr C MoxGM95 wt. No double mutant had emerged. In the mutant, c MoxGM95 wt Pu2, the viability was greatly reduced. These results suggested that phenoloxidase and tyrosine-3-hydroxylase act as indispensable proteins to maintain life in Drosophila.

Animals↗
PubMedDate not supplied

Acidification of extracellular environment inhibits CCK-8-induced Ca2+ entry into pancreatic acinar cells of rat evaluated by a Mn(2+)-quenching method.

The fluorescence of fura 2, a Ca(2+)-sensitive dye, is quenched in the presence of other divalent cations such as Mn2+. This characteristic of the dye provides a useful measure for investigating the role of Ca2+ in cellular functions. The present experiments were thus designed to examine the effects of extracellular pH (pHo) on cholecystokinin octapeptide (CCK-8)-induced Ca2+ entry into isolated perifused pancreatic acini of the rat using a Mn(2+)-quenching method. At a standard pHo (7.4), addition of Mn2+ (1 mM) during continuous stimulation with 100 pM CCK-8 quenched fura 2 fluorescence excited by both excitation wavelengths of 340 and 380 nm. Lowering pHo to 6.0 weakened the quenching, whereas elevating pHo to 8.0 during the stimulation accelerated the quenching compared with that at standard pHo. Accordingly, when acinar cells were stimulated continuously with 100 pM CCK-8 at pHo 6.0, the second sustained increase in cytosolic Ca2+ concentration ([Ca2+]i) was decreased compared with that at pHo 7.4, but the [Ca2+]i increase reappeared when the pHo was neutralized from 6.0 to 7.4 even after cessation of the stimulation. The second sustained increase of [Ca2+]i was achieved at pHo 8.0, but it declined rapidly when CCK-8 stimulation was terminated and pHo was simultaneously restored to 7.4. Amylase release induced by continuous stimulation with 100 pM CCK-8 showed a biphasic time course. A second sustained phase of amylase release was significantly reduced at pHo 6.0, but amylase release increased again when pHo was restored to 7.4. These results indicate that extracellular pH modifies the extent of secretagogue-induced Ca2+ entry into the pancreatic acinar cell, and the inhibitory effects of lowered pHo on the secretory response are largely due to a limited increase in [Ca2+]i.

Amylases↗
PubMedDate not supplied

Aggressive fibromatosis from infancy to adolescence.

Aggressive fibromatosis is a rare fibroproliferative disorder with a variable biologic potential that is locally morbid but does not metastasize. Eighteen patients with extraabdominal fibromatosis were treated with a multidisciplinary approach over a 27-year period. Our observations, coupled with a review of the literature, suggest that conservative surgery with the goal of a wide margin coupled with adjuvant therapies may result in adequate control of disease from infancy to adolescence. Amputation should be reserved for cases in which the disease or its treatment have resulted in a nonfunctional or chronically painful extremity. Radiation should be used as a last resort in the skeletally immature because of the risk of growth disturbance, contracture, and secondary malignancy. Chemotherapy may have a role in children with inoperable disease, in those who have gross residual tumor after an intralesional procedure, for disease progression or recurrence, and neoadjuvant therapy should be investigated as a means to achieve a wide margin in some cases.

Adolescent↗
PubMedDate not supplied

De novo deletions of p53 gene and wild-type p53 correlate with acquired cisplatin-resistance in human osteosarcoma OST cell line.

BACKGROUND: Initial p53 status is a useful determinant of chemoresistance or chemosensitivity of primary tumors, however, it remains unclear whether p53 status is a critical chemoresistant marker in tumors that acquire drug-resistance after the initiation of chemotherapy. We investigated the relationship between p53 status and the development of resistance to cisplatin in osteosarcoma cell lines. MATERIALS AND METHODS: Cisplatin-sensitive human osteosarcoma OST cells and acquired cisplatin-resistant OST/R cells derived from OST cells were used. Single-strand conformation polymorphism (SSCP) analysis of exons 5 to 8, and immunohistochemistry using anti-p53 antibodies were analyzed to detect mutations of p53. Fluorescence in situ hybridization (FISH) and enzyme immunoassay (EIA) were performed to detect deletions of p53. RESULTS: SSCP and immunohistochemistry revealed that both cell lines had wild-type p53 gene and protein. However, in OST/R cells, genomic instability of chromosome 17 and de novo deletion of the p53 gene located in chromosome 17p were detected by FISH. The constitutive levels of wild-type p53 protein measured by EIA were significantly lower in OST/R cells than in OST cells. Furthermore, p53 induction was lost in OST/R cells after cisplatin exposure. CONCLUSIONS: De novo deletions of the p53 gene and wild-type p53 were associated with the acquisition of cisplatin-resistance in osteosarcoma.

Antineoplastic Agents↗
PubMedDate not supplied

Caffeine-potentiated radiochemotherapy and function-saving surgery for high-grade soft tissue sarcoma.

Caffeine, which has a DNA-repair inhibiting effect, enhances the cytocidal effects of anticancer drugs and radiation. We present a preliminary report on the results of a new treatment, "radiochemotherapy combined with caffeine" (K3 protocol), for high-grade soft tissue sarcomas. Seventeen patients with various high-grade soft tissue sarcomas were included in this study. Preoperatively, three to five courses of intra-arterial chemotherapy using cisplatin, caffeine and doxorubicin after radiation therapy were administered. Following the preoperative therapy, function-saving surgery was performed for all cases. Complete response was observed in six patients, partial response in six and no change in five. The effectiveness rate of caffeine-potentiated radiochemotherapy was therefore 71%. The histological response for radiochemotherapy was better than that for chemotherapy alone, that is, total tumor necrosis was identified in six patients and over 90% necrosis in another six. Complications resulting from the preoperative radiation comprised of serious inflammation in three patients and skin necrosis in another three. Twelve patients have remained free of disease, two patients are alive with disease and three have died of metastatic disease with a mean follow-up period of 36 months. There was no local tumor recurrence. These preliminary findings suggest that caffeine-potentiated radiochemotherapy contributed to a satisfactory local response and the success of function-saving surgery for high-grade soft tissue sarcomas.

Adolescent↗
PubMedDate not supplied

Disappearance of Ewing's sarcoma following bacterial infection: a case report.

We report a patient with multiple metastases of Ewing's sarcoma in whom the tumor vanished after a bacterial infection. To the best of our knowledge, no comparable case with Ewing's sarcoma has been reported in the literature. The patient was a 17-year-old male who had an irregular destructive lesion of the left pelvis on radiologic examination. Pathologic examination of a biopsy specimen revealed Ewing's sarcoma. After the operation, a roentgenogram showed multiple spinal metastases with paraplegia. Despite initiation of chemotherapy, a subsequent bone scan showed several areas of increased uptake indicating multiple metastatic lesions. A fistula with purulent discharge opened at the operative site. While being treated with antibiotics and fistula irrigation, the fistula narrowed and his high fever subsided. During this period, radiologic examinations indicated that the multiple bone metastases had nearly disappeared. Nine years after the operation, the patient is alive without any evidence of tumor. We postulate that the antitumor activity in this patient resulted from the bacterial infection, and believe that this case supports continued consideration of immunotherapy for cancer.

Adolescent↗
PubMedDate not supplied

Caffeine-assisted chemotherapy and minimized tumor excision for nonmetastatic osteosarcoma.

Osteosarcoma is usually treated with intensive preoperative and postoperative chemotherapy and wide tumor resection, resulting in a 60% to 70% 5-year survival rate. Caffeine has a DNA-repair inhibiting effect. We therefore investigated the impact of caffeine given in conjunction with chemotherapy and limb-sparing surgery on survival and local tumor control in patients with nonmetastatic, high-grade osteosarcoma. Twenty-two patients were given 3 to 5 preoperative courses of intra-arterial cisplatin (120 mg/m2, 1 to 2 hours) and caffeine (1.5 g/m2/day x 3 days) with or without doxorubicin (30 mg/m2/day x 2 days). Following this treatment, limb-sparing surgery was performed by means of intentional marginal excision aiming at preservation of important structures such as major neurovascular bundles, tendons, ligaments and the epiphysis. Three courses of cisplatin and doxorubicin combined with caffeine, and high-dose methotrexate with vincristine and citrovorum factor rescue were given intravenously as postoperative chemotherapy for 21 patients and three courses of high-dose methotrexate and combination of ifosfamide, etoposide and methotrexate for 1 patient. Following the preoperative chemotherapy, there were no viable tumor cells in 19 patients, only scattered foci of viable cells in 2 patients, and some areas of viable tumor cells in 1. The 21 patients with a good chemotherapeutic response on radiographs underwent minimized marginal excision. Functional evaluation of the affected limbs was excellent for 17 patients, good for 3, fair for 1, and poor for 1. No local tumor recurrence was seen in this series. Eighteen patients remain disease-free with a mean follow-up of 61 months. Two patients died of metastatic disease, 1 died of chemotherapy-related complications, and 1 died of unknown causes. The overall 5-year cumulative survival rate was 90%, and the 5-year event-free survival rate was 75%. Chemotherapeutic caffeine enhanced tumor necrosis and improved the success rate of limb-sparing surgery using marginal procedure without any adverse impact on survival. The results of our limited clinical trial appear to justify further prospective, multicenter randomized trials of the benefits of caffeine combined with chemotherapy for nonmetastatic osteosarcoma and other malignant neoplasms.

Adolescent↗
PubMedDate not supplied

Establishment and characterization of an acquired cisplatin-resistant subline in a human osteosarcoma cell line.

A cisplatin (CDDP)-resistant human osteosarcoma cell line (OST/R) was established by continuous exposure to CDDP. OST/R cells proved to be 6.73 times more resistant to CDDP compared with parental OST cells, and showed cross-resistance to carboplatin (CBDCA). The mechanism of CDDP resistance was a significant decrease of intracellular platinum accumulation which was 40% of that in OST cells. OST/R cells were exposed to CDDP for 6 hours, the platinum was released from the cytoplasm of OST/R cells without reaching a state of equilibrium. DNA synthesis in OST/R cells was not inhibited by CDDP exposure, while in OST cells it was reduced by 50%. These data provide the first evidence that the increased efflux of platinum may play an important role in CDDP-resistance.

Antineoplastic Agents↗