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Biomedical subjects

K Takai

Publications and source records attributed to K Takai.

At least 271 records · Page 15Linked to original sources
PubMed1982

[Therapeutic results of DCMP therapy (2M-80) in acute non-lymphocytic leukemia--the relationship between the residual leukemic cells and duration of remission].

In this study the duration of complete remission by daunomycin, cytosine arabinoside (Ara-C), 6MP and prednisolone (DCMP) therapy using a large dose of Ara-C (200 mg) (protocol 2M-80) was compared with that of DCMP therapy with a low dose of Ara-C (80-160 mg) in acute non-lymphocytic leukemia (ANLL). In protocol 2M-80, the chemotherapy was continued until leukemic blasts in marrow were attained below 3%. Complete remission was induced in about 80% of ANLL patients in both chemotherapies. However, the duration of remission in protocol 2M-80 appeared to be much longer than that of DCMP therapy with a low, dose of Ara-C. This difference was dependent not on the consolidation and maintenance therapy, but on the total dose of Ara-C used and leukemic blasts left in marrow at the end of chemotherapy. This suggests that it is important to reduce leukemic blasts in marrow as low as possible by induction chemotherapy to obtain a long-term remission in ANLL.

Acute Disease↗
PubMed1982

A new method for colony formation in vitro by leukemic cells in acute nonlymphocytic leukemia with PHA-stimulated lymphocyte conditioned medium as stimulating factor.

A new agar culture system to clone specifically acute nonlymphocytic leukemia (ANLL) is described, which consists of two phases: an initial liquid phase in the presence of PHA-stimulated lymphocyte conditioned medium (PHA-LCM) and a semi-solid phase. By preincubation of leukemic cells with PHA-LCM in a liquid phase, leukemic cells were found to be more sensitive to forming colonies and clusters in agar medium. In addition, this PHA-two step assay could eliminate colony formation by T cell progenitors. The leukemic origin of the colonies was proven by electron-microscopic analysis, which demonstrated the presence of nuclear blebs and abnormal perinuclear fibril formation. Morphological studies also indicated myeloid differentiation of the cells in the leukemic colonies, although considerable variation was observed among patients. The wide range of linearity between the number of cells plated and the number of colonies grown permits quantitative assay of colony-forming leukemic cells (L-CFU). This assay should be valuable for studies of chemotherapy, growth regulation, and differentiation of L-CFU.

Acute Disease↗
PubMed1982

[Infections during induction chemotherapy of acute leukemia and their control V. Clinical evaluation of a large dose of amikacin injected intravenously].

In this study, we treated severe infections (21 cases) accompanied with induction chemotherapy in 20 patients with acute leukemia by the combination of a large dose (600 approximately 1,200 mg/day) of amikacin with other antibiotics. Infections during induction chemotherapy of acute leukemia consisted of sepsis (8 cases), pneumonia (7) and others (6), and most of causative organisms were Gram-negative bacteria, such as Ps. aeruginosa (7 strains), Flavobacterium (5), Serratia (3), Ps. cepacia (2), E. coli (2) and others. The combination chemotherapy of a large dose of amikacin with other antibiotics was found to be effective (71.4%) for such infections. Side effects were negligible except for drug eruption. Therefore, a large dose of amikacin should be given for the treatment of severe infections accompanied with induction chemotherapy of acute leukemia.

Adolescent↗
PubMed1982

[An in vitro chemotherapy sensitivity test on leukemic colony-forming cells (L-CFU) and its clinical evaluation].

The sensitivity of leukemic progenitor cells (L-CFU) to cytosine arabinoside (Ara-C) and daunomycin (DM) in vitro was studied using PHA -LCM two step assay for L-CFU. Continuous exposure of leukemic and normal bone marrow cells to DM as well as Ara-C in vitro appeared to be more effective than pulse exposure because colony formation was suppressed by a dose dependent fashion. The relationship between in vitro sensitivity to DM and Ara-C and that of in vivo to chemotherapy was investigated in 17 untreated and 5 relapsed patients with acute nonlymphocytic leukemia. The sensitivity of L-CFU to the two chemotherapeutic agents varied from patient to patient. These studies indicated a clear-cut relationship between in vitro drug sensitivity and in vivo response to patients whose L-CFU were sensitive to both agents and entered complete remission, whereas patients whose L-CFU were insensitive to one or both drugs in vitro failed to enter remission. This assay system appears to be useful in predicting response of patients to chemotherapy and in selecting the most effective drugs for an individual patient use.

Acute Disease↗
PubMed1981

Enzymatic modification of tryptophan residues by tryptophan side chain oxidase I and II from Pseudomonas.

The enzymatic modification of tryptophan residues in Trp-Leu, Leu-Trp, Leu-Trp-Leu, and yeast mating hormone (alpha-factor), a tridecapeptide containing Trp-1 and Trp-3, has been investigated with tryptophan side chain oxidase I crystallized previously from Pseudomonas and tryptophan side chain oxidase II recently isolated from the same organism. With Trp-Leu as substrate, threo- and erythro-beta-hydroxytryptophan residues were identified as primary products and the former perferentially underwent second step dehydrogenation to give beta-ketotryptophan. Free threo- and erythro-beta-hydroxytryptophan, hitherto undescribed tryptophan derivatives, were isolated after enzymatic hydrolysis, identified, and characterized. Leu-alpha, beta-dehydrotryptamine, a new biochemical entity, was a sole main product of Leu-Trp. With Leu-Trp-Leu, diastereoisomeric Leu-beta-hydroxyl-Trp-Leu and Leu-alpha, beta-dehydro-Trp-Leu were formed simultaneously, the pH and ionic strength being determinants of the ratio of these products. Leu-threo-beta-hydroxy-Trp-Leu was also converted to Leu-beta-keto-Trp-Leu, but, distinct from NH2-terminal beta-hydroxytryptophan, both diastereoisomers underwent acid-catalyzed dehydration to give Leu-alpha, beta-dehydro-Trp-Leu. Thus, the mode of modification was shown to be prescribed by the site of tryptophan in peptides and the results were the same with either tryptophan side chain oxidase I or II, except that the latter was almost inactive on Trp-Leu. With any substrate, 3-indolecarboxaldehyde was a sole detectable by-product.

Magnetic Resonance Spectroscopy↗
PubMed1981

Neurotensin and substance P and dumping syndrome.

To investigate the pathophysiological relation between releases of gut hormones and dumping syndrome, plasma radioimmunoassayable neurotensin, substance P, glucagon-like immunoreactivity (GLI), insulin and blood sugar were measured in both gastrectomized patients and control subjects after 50 g oral glucose tolerance tests. Remarkable rises of radioimmunoassayable neurotensin and GLI were found in all gastrectomized patients, but not in control subjects. In contrast, plasma radioimmunoassayable substance P responses were not detected in either gastrectomized patients or control subjects. There were three patients with symptoms of dumping syndrome in the early stage of the test. Plasma radioimmunoassayable neurotensin responses in two out of these three were higher than those in other patients, though the other patient with symptoms had the same degree of neurotensin elevation as patients with no symptoms. In view of the pharmacological effects of neurotensin, it could not be ruled out that a part of the early symptoms of dumping syndrome may result from the remarkably enhanced plasma neurotensin release in some patients, although the enhanced neurotensin responses did not always accompany symptoms of dumping syndrome.

Adult↗
PubMed1979

Isolation and reconstitution of two electron transfer components of tryptophan side chain oxidase.

The isolation and reconstitution of two electron transfer components of tryptophan side chain oxidase from Pseudomonas (ATCC 29574) are described. The dehydrogenase component abstracts electrons from the substrate and transfers them to oxidation-reduction dyes such as potassium ferricyanide and 2,6-dichlorophenolindophenol but not to molecular oxygen. It is composed of a single polypeptide chain with a molecular weight of 72,000 and exhibits the absorption spectrum of a reduced b-type cytochrome with maxima at 563, 532, 433, 323, and 278 nm. The oxidase component transfers electrons, derived from the former component, to oxygen, and has a molecular weight of 48,000. The absorption spectrum exhibits broad peaks at 680, 438, and 358 nm, and a peak at 280 nm. On sucrose gradient centrifugation and polyacrylamide gel electrophoresis, these two components are shown to form a molecular complex, which has the reconstituted oxidase activity. The turnover number of the reconstituted enzyme is comparable to that of the native enzyme.

Electron Transport↗
PubMed1979

[A radioimmunoassay for plasma parathyroid hormone (PTH) using N-terminal PTH antiserum (author's transl)].

In order to investigate plasma bioactive PTH, we tried to assay the N-terminal portion of PTH by RIA. The antiserum to PTH was prepared by immunizing rabbits with a bovine 1-34 PTH conjugate BSA. A preparation of labeled PTH was radioiodinated by the chloramine-T or lactoperoxidase method. Labeled PTH was purified by means of adsorption by Quso G-32 powder or a sephadex G-50. The separation of the free and bound labeled hormone was performed by the dextran-coated charcoal method. The assay was carried out as follows: 0.2 ml diluted buffer (0.05 M, pH 8.6, veronal buffer), 0.1 ml standard PTH or sample to be tested, and 0.1 ml anti-PTH serum were mixed. After the first incubation at 4 degrees C for 4 days, 0.1 ml labeled PTH were added. After a second incubation at 4 degrees C for 12 hours, the assay tubes were centrifuged at 2,000 rpm for 30 min and the precipitates were counted. Various hypothalamic, pituitary and thyroid hormones did not interfere with the RIA for PTH. A dose response curve was obtained in a range from 100 pg to 5,000 pg per ml of standard PTH in this assay system. The serum immunoreactive PTH in healthy subjects values less than 290 pg per ml.

Animals↗