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Biomedical subjects

Y Kodera

Publications and source records attributed to Y Kodera.

At least 271 records · Page 15Linked to original sources
PubMed1988

[Phase II study of carboplatin in malignant lymphoma].

A phase II study of carboplatin for malignant lymphoma was conducted. Thirty-nine patients with malignant lymphoma were entered into this study, and 6 of them were excluded from evaluation due to violation of selection criteria. The remaining 33 cases were studied to assess the effectiveness and safety of this drug. Two CR and 11 PR were obtained with this medication (effective rate 39%). The significant affecting factors were previous treatment, disease stage and P.S. score. Many cases suffered from gastrointestinal symptoms and reduced hematopoiesis. The former complication was self-limited without any fatal episodes. However, the latter included severe cases, especially thrombocytopenia, which is suggested to be a dose limiting factor (DLF) of this drug.

Adolescent↗
PubMed1987

Polyethylene glycol derivative-modified cholesterol oxidase soluble and active in benzene.

Cholesterol oxidase from Nocardia sp. was modified with a synthetic copolymer of polyoxyethylene allylmethyldiether (PEG) and maleic acid anhydride (MA anhydride), poly(PEG-MA anhydride). The modified cholesterol oxidase, in which 64% of the amino groups in the protein molecule were coupled to poly(PEG-MA), was soluble in organic solvents and catalyzed the oxidation reaction of cholesterol in benzene to form 4-cholesten-3-one with the enzymic activity of 0.6 mumol/min/mg protein. Using the modified cholesterol oxidase together with polyethylene glycol-modified peroxidase, coupled reactions shown below took place in Cholesterol + O2----4-Cholesten-3-one + H2O2 H2O2 + o-Phenylenediamine----H2O + Oxidized o-Phenylenediamine transparent benzene solution, not in an emulsified system. The oxidation of cholesterol was directly determined in benzene by measuring the absorbance of oxidized o-phenylenediamine at 490 nm.

3-Hydroxysteroid Dehydrogenases↗
PubMed1987

Fibrinolysis by urokinase endowed with magnetic property.

The activated magnetic modifier was synthesized from magnetite, alpha, omega-dicarboxymethylpoly(oxyethylene) and N-hydroxysuccinimide (Biochem. Biophys. Res. Commun., 145, 908-914, 1987). Urokinase was directly coupled with the activated magnetic modifier to obtain magnetic urokinase. The magnetic urokinase dispersed in saline and exerted high fibrinolytic activity (13.8 X 10(4) IU/mg protein), and was readily recovered from saline by magnetic force of 250 Oe. By applying magnetic force, the urokinase was attracted at our will and local fibrinolysis was achieved on fibrin gel in a petri dish.

Fibrinolysis↗
PubMed1987

Environment-dependent conformation and antimicrobial activity of a gramicidin S analog containing leucine and lysine residues.

An analog of gramicidin S, cyclo(-L-Leu-L-Lys-L-Leu-D-Leu-L-Leu-)2, in which four out of five amino acid components of gramicidin S were substituted, has been synthesized. This analog assumes a conformation similar to that of gramicidin S in acidic liposomes and a random conformation in neutral liposomes. The antimicrobial activity of this analog corresponded to one-fourth of that of gramicidin S. A possible mechanism for conformational changes in acidic liposomes is discussed.

Amino Acid Sequence↗
PubMed1987

Magnetic lipase active in organic solvents.

Magnetic lipase (magnetite particles coated with polyethylene glycol-modified lipase) was prepared in two steps: Lipase was coupled with 2,4-bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine, activated PEG2, to obtain polyethylene glycol-modified lipase, PEG-lipase. The PEG-lipase was added to the solution of ferrous (Fe2+)- and ferric(Fe3+)-ions with the pH value adjusted to 8.0-8.5 to obtain magnetic lipase. The magnetic lipase was dispersed in organic solvents such as benzene and 1,1,1-trichloroethane with the particle size of 120 +/- 60 nm. The colloidal solution was very stable and no aggregation occurred even after 5 days. A high enzymic activity (11.6 mumol/min/mg protein) for lauryl laurate synthesis was observed in 1,1,1-trichloroethane. The magnetic lipase was readily recovered from the organic solvents in a magnetic field of 6000 Oe without loss of the enzymic activity.

Benzene↗
PubMed1987

Digital image processing of dentomaxillofacial radiographs.

The improvement in the image quality of dentomaxillofacial radiographs (panoramic radiographs) with the use of a digital image-processing system was examined. Linear and nonlinear unsharp masking techniques were employed for image processing. The quality of the processed images was found to be markedly improved over that in original radiographs. The detail visibility of linearly enhanced images, especially in low-density areas, was superior to that of nonlinearly enhanced images, although the presence of more artifacts and more noise was noted in linearly enhanced images. Radiographic diagnosis in the dentomaxillofacial region can be improved with this system.

Humans↗
PubMed1987

Dinitrofluoranthene: induction, identification and gene mutation.

By renitrating 3-nitrofluoranthene in the presence of fuming nitric acid, some additional nitro-derivatives were induced; they were identified as 3,7-, 3,9- and 3,4-dinitrofluoranthene (DNF), and two trinitrofluoranthenes (TNF, 3,4,7- and 3,4,8- or 3,4,9-isomers) on the basis of the results of mass spectrometry and 1H-nuclear magnetic resonance. The yield of 3,7- and 3,9-DNF was about 61.3% in all of the derivatives induced. All of the DNFs yielded positive results in the rec-assay system, inducing DNA-damaging activity in Bacillus subtilis. Both 3,7- and 3,9-DNF converted Salmonella typhimurium His- strains TA98, TA97 and TA1538 from autotrophy to prototrophy, indicating a frameshift-type mutation for both; for strain TA98, 3,7-, 3,9- and 3,4-DNF gave mutagenicity of 422, 355 and 15.5 His+ revertants, respectively, per nanogram, corresponding to the specific activity of 1,6-dinitropyrene (DNP), a powerful mutagen. These DNFs are known to be potential mutagens which are eluted at adjacent retention times with 1,3-, 1,6- and 1,8-DNP on a column for high-performance liquid chromatography.

Bacillus subtilis↗
PubMed1987

Empirical rules predicting conformation of cyclic tetrapeptides from primary structure.

A useful set of empirical rules is put forward to predict the conformations of cyclic tetrapeptides and cyclic tetradepsipeptides on the basis of primary structure, briefly presented as follows: A conformation allowing an intramolecular hydrogen bond (IMHB) of gamma-turn is preferred, and an ester bond always adopts a trans form. On a right-handed peptide ring, the carbonyl group acylating a D residue is oriented to the upper side of the main ring. The carbonyl group acylating a D proline or an N-methyl-D-amino acid residue is oriented to the lower side of the ring, forming a cis bond. The LDDL configurational sequence adopts a cis-trans-cis-trans backbone with Ci symmetry. A glycine residue behaves as a D residue in an L-peptide. Conformations of cyclotetrapeptides containing two glycine residues at diametric positions or containing an N-methyl-dehydroamino acid residue are predicted by use of appendices of rule 5. Almost all conformations of cyclic tetrapeptides are predicted by these rules. Energetical rationalization of the rules and prediction of possible new conformations are described. Conformations of cyclo(-L-Pro-L-Leu-D-Tyr(Me)-L-Ile-)(1) and cyclo (-L-Pro-D-Leu-D-Tyr(Me)-L-Ile)(2) are compared. Results of n.m.r. experiments showed that compound 1 adopts a unique cis-trans-trans-trans backbone with a gamma-turn IMHB, and 2 has a cis-trans-cis-trans backbone with Ci symmetry. These observations confirmed the rules described above. Peptides 1 and 2 are the first diastereomeric peptides with trans (LD) and cis (DD) secondary amide bonds.

Magnetic Resonance Spectroscopy↗
PubMed1987

Treatment of adult T cell leukemia with mega-dose cyclophosphamide and total body irradiation followed by allogeneic bone marrow transplantation.

A 43-year-old patient with adult T cell leukemia (ATL) was treated with mega-dose cyclophosphamide and total body irradiation (TBI) followed by bone marrow transplantation (BMT) from his HLA-identical sibling who was not a carrier of ATL virus. After BMT, ATL cells rapidly decreased and disappeared, and the engraftment of marrow was confirmed on day 20. The patient showed normal hematologic recovery. However, he died on day 205 with interstitial pneumonitis caused by cytomegalovirus infection. Neither autopsy findings nor serologic and cytologic examinations showed any evidence of ATL relapse after BMT. This pilot study suggests that mega-dose chemotherapy and TBI followed by allogeneic BMT should be considered for such treatment of ATL.

Adult↗
PubMed1987

Preservation of natural killer and interleukin-2 activated killer cell activity in ataxia-telangiectasia with T cell deficiency.

Peripheral blood mononuclear cells (PBMs) from 6 patients with ataxia-telangiectasia (AT) were studied by 5 kinds of cell-mediated cytotoxicity systems. Decrease in cell mediated lympholysis (CML) activity to allogeneic lymphocytes was observed in all 6 AT patients who had low numbers of OKT-3+ cells. These patients also showed decreased proliferative responses to phytohemagglutinin stimulation and allogeneic lymphocytes. In contrast, antibody-dependent cell-mediated cytotoxicity (ADCC) activity and natural killer (NK) activity were comparable with those in normal controls. In addition, PBMs from these AT patients activated by in vitro stimulation with allogeneic PBMs or interleukin-2 were able to acquire lytic activity against NK-insensitive target cells. The phenotypes of these effectors determined by complement-mediated lysis were OKT-3- and Leu-11+, suggesting that they were derived from NK cell lineage. Thus, AT patients with severe T cell defects were found to maintain a normal range of NK, ADCC, MLC-activated and lymphokine-activated killer activity.

Adolescent↗
PubMed1986

Randomized controlled study of chemoimmunotherapy of acute myelogenous leukemia (AML) in adults with Nocardia rubra cell-wall skeleton and irradiated allogeneic AML cells.

The effect of immunotherapy with Nocardia rubra cell-wall skeleton (N-CWS) on remission duration and survival of adults with acute myelogenous leukemia (AML) was studied in a prospective randomized controlled study. After having been induced into complete remission and having been consolidated, 73 patients were randomized either to maintenance chemotherapy or maintenance chemotherapy plus immunotherapy with N-CWS and irradiated allogeneic AML cells. Thirty-four patients in the chemotherapy group and 32 in the chemoimmunotherapy group were evaluable. Six months after the closure of the study, the immunotherapy showed a borderline beneficial effect on remission duration (P = 0.080) and on survival length (P = 0.098). When the data were analyzed at 30 months after the entry, there was a borderline significant difference in remission duration (P = 0.080) between the two groups, prolonging the 50% remission period by 110 days; but no significant difference in survival length (P = 0.314), although the 50% survival was 168 days longer in the chemoimmunotherapy group. However, there were 4 (18.2%) 5-year relapse-free survivors among 22 patients (11 in each group) who had been diagnosed more than 5 years before the time of the present analysis, and all of them belonged to the chemoimmunotherapy group (P = 0.090). Thus, immunotherapy with N-CWS and irradiated allogeneic AML cells seems to be active in the treatment of adult AML when used for maintenance therapy in combination with chemotherapy.

Adolescent↗