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Biomedical subjects

Y Kodama

Publications and source records attributed to Y Kodama.

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

Micronucleated reticulocyte induction by ethylating agents in mice.

Six model ethylating agents were tested for clastogenic potency by means of a new technique of the micronucleus assay with mouse peripheral blood cells using acridine orange (AO)-coated slides, to evaluate the test. The alkylating agents were: N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG), N-ethyl-N-nitrosourea (ENU), diethylsulfate (DES), ethyl methanesulfonate (EMS), epichlorohydrin (ECH) and ethylene dibromide (EDB). The animals were given a single intraperitoneal injection of the following doses of the chemicals: ENNG and ENU, 25, 50 and 100 mg/kg; EMS and DES, 100, 200 and 400 mg/kg body weight. For EDB and ECH, the doses were 50, 100 and 200 mg/kg, given twice, 24 h apart. Before and after the injection, blood samples were taken from the tails at 24-h intervals up to 72 h and preparations were made on AO-coated slides. For each dose group, 4 animals were used and 1000 reticulocytes were examined per slide for the presence of micronuclei. At the optimum induction time of 48 h, ENU induced micronucleated reticulocytes (MNRETs) at all 3 doses. ENNG and EMS induced MNRETs significantly at 2 dose levels each and DES only at the highest dose. ECH and EDB failed to induce MNRETs. On the basis of the dose of chemical needed to double the spontaneous frequency, the order of clastogenic potency was ENU greater than ENNG greater than EMS greater than DES. The results obtained compared favorably with those from other in vivo methods. The present technique proves to be simple, flexible and relatively sensitive. Shifts in the optimum induction peak in individual animals and by some chemicals can be picked up easily which is important when testing weak mutagens and chemicals with an unknown mechanism of action.

Alkylating Agents↗
PubMed1992

Rapid translocation frequency analysis in humans decades after exposure to ionizing radiation.

This paper presents an analysis of the utility of fluorescence in situ hybridization (FISH) with whole-chromosome probes for measurement of the genomic frequency of translocations found in the peripheral blood of individuals exposed to ionizing radiation. First, we derive the equation: Fp = 2.05fp(1-fp)FG, relating the translocation frequency, Fp, measured using FISH to the genomic translocation frequency, FG, where fp is the fraction of the genome covered by the composite probe. We demonstrate the validity of this equation by showing that: (a) translocation detection efficiency predicted by the equation is consistent with experimental data as fp is changed; (b) translocation frequency dose-response curves measured in vitro using FISH agree well with dicentric frequency dose-response curves measured in vitro using conventional cytogenetic procedures; and (c) the genomic translocation frequencies estimated from FISH measurements for 20 Hiroshima A-bomb survivors and four workers exposed to ionizing radiation during the Y-12 criticality accident are approximately the same as the translocation frequencies measured using G-banding. We also show that translocation frequency dose response curves estimated using FISH are similar for Hiroshima A-bomb survivors and for first division lymphocytes irradiated in vitro. We conclude with a discussion of the potential utility of translocation frequency analysis for assessment of the level of acute radiation exposure independent of the time between analysis and exposure.

Accidents↗
PubMed1992

Binding parameters of valproic acid to serum protein in healthy adults at steady state.

Two hundred milligrams of valproic acid (VPA) was administered orally to seven healthy adults at 9:00 and 21:00 h for 5 consecutive days, including the morning dose on day 6. On the sixth day, blood samples were drawn at 0, 0.17, 0.33, 0.5, 0.75, 1, 1.5, 3, and 6 h after the morning dose. Binding of VPA to serum protein was evaluated by ultrafiltration, and total and unbound VPA concentrations were determined by fluorescence polarization immunoassay. Binding parameters of VPA to serum protein were calculated for each subject by the Scatchard analysis. The binding parameters obtained from seven subjects showed that the mean association constant (K) was 2.72 x 10(4) L/mol while the total number of binding sites (nPt) was 789 mumol/L. There were marked interindividual variations and the coefficient of variation was 42% for K and 28% for nPt. These results show that endogenous free fatty acids (FFAs) significantly reduce the binding affinity of VPA to serum albumin (p less than 0.05). In addition, they suggest the possibility that the primary binding sites for VPA can be strongly reduced by FFAs. Therefore, we consider that interindividual differences in binding parameters may be clinically important.

Adult↗
PubMed1992

Prediction of unbound serum valproic acid concentration by using in vivo binding parameters.

In a previous study, we determined the in vivo binding parameters of valproic acid (VPA) to serum proteins in seven healthy young adults at steady state by using the Scatchard equation. To evaluate the ability of the Scatchard binding equation to predict steady-state unbound serum VPA concentrations (Cf), 39 adult patients receiving VPA monotherapy and ranging in age from 16 to 68 years were studied. The correlation between predicted and observed Cf was high (r = 0.865). Mean prediction error, mean absolute error (MAE), and root mean squared error (RMSE) were calculated, and served as a measure of prediction bias and precision. The MAE and RMSE were low (MAE = 12.9 mumol/L, RMSE = 17.7 mumol/L). It is feasible to use the Scatchard binding equation to predict Cf in patients receiving VPA monotherapy.

Adolescent↗
PubMed1992

Reclassification of two strains of Arthrobacter oxydans and proposal of Arthrobacter nicotinovorans sp. nov.

Arthrobacter oxydans DSM 419 and DSM 420 have chemical and microbiological properties that are consistent with assignment to the genus Arthrobacter. Both organisms have the lysine-alanine-threonine-alanine peptidoglycan type. DNA-DNA pairing studies indicated that A. oxydans DSM 419 should be reclassified as Arthrobacter ureafaciens and that A. oxydans DSM 420T forms the nucleus of a distinct genomic species. We propose that A. oxydans DSM 420 should be reclassified as Arthrobacter nicotinovorans sp. nov. The type strain is strain DSM 420.

Amino Acid Sequence↗
PubMed1992

Passive protective effect of chicken egg yolk immunoglobulins against experimental enterotoxigenic Escherichia coli infection in neonatal piglets.

Passive protection of neonatal piglets against fatal enteric colibacillosis was achieved with powder preparations of specific antibodies against K88, K99, and 987P fimbrial adhesins of enterotoxigenic Escherichia coli. The antibody powders were obtained by spray drying the water-soluble protein fraction of egg yolks from immunized hens after the lipid components were precipitated with an aqueous dispersion of acrylic resins (Eudragit L30D-55; Rohm pharma). The anti-K88, -K99, and -987P antibody preparations reacted specifically against the corresponding fimbrial antigens in an enzyme-linked immunosorbent assay. The orally administered antibodies protected in a dose-dependent fashion against infection with each of the three homologous strains of E. coli in passive immunization trials with a colostrum-deprived piglet model of enterotoxigenic E. coli diarrhea. Scanning electron microscopy revealed adherence of enterotoxigenic E. coli in intestinal epithelial surfaces of control piglets, whereas in treated piglets treated with high-titer antibodies, a resistance to bacterial adhesion was observed. An enzyme immunoassay with avidin-biotin complex demonstrated specific local antibody activity in target areas of the small intestines. In vitro, E. coli K88+, K99+, and 987P+ strains adhered equally to porcine duodenal and ileal epithelial cells but failed to do so in the presence of homologous anti-fimbrial antibodies. Absorption of egg yolk antibodies with fimbrial immunosorbent removed the anti-fimbrial antibody fraction and reduced significantly the protective nature of the antibody preparation in a passive immunization experiment, suggesting that anti-fimbrial antibodies were the active components.

Animals↗
PubMed1992

Factors that determine the in vivo dose-response relationship for stable chromosome aberrations in A-bomb survivors.

An overview is given of the dose-response relationship for stable chromosome aberrations (i.e., translocations and inversions) in the peripheral blood lymphocytes of A-bomb survivors in Hiroshima. Special emphasis is placed on (i) the overdispersion of survivor cases with either unexpectedly high or low aberration frequencies relative to the estimated DS86 kerma values assigned to individual survivors, termed "cytogenetic outliers", and (ii) the correlation of chromosome aberration frequencies with other biological endpoints, such as acute radiation symptoms (severe epilation). A new molecular biological technique, known as fluorescence in situ hybridization (FISH) with composite, whole-chromosome probes to paint differentially the target chromosomes, has facilitated rapid, efficient, and extensive scoring of translocation-type chromosome aberrations in which the target chromosomes are involved. Using this methodology, the observed findings on translocation frequencies in A-bomb survivors have shown that the frequency of stable chromosome aberrations, which have persisted for years without change in frequency in irradiated persons, is indeed useful as an indicator for biological dosimetry.

Chromosome Aberrations↗
PubMed1992

[A simple method for measuring cleaning solvent in air by gas detector tube for ethyl acetate].

A simple method for measuring cleaning solvent in air by gas detector tube for ethyl acetate was evaluated with regard to basic performance such as sensitivity, precision, discolor tone and effect of temperature. Satisfactory results were obtained with regard to sensitivity, precision, discolor tone in the indicator and stability of discolored length. Range of measurable concentration by the present method was about 25-800 mg/m3. It was found necessary in the present method to make temperature correction. It was concluded from these results that the present method is useful for measuring cleaning solvent in air. However, positive effect on discolored length was found by vapor of toluene and ethyl acetate when they coexisted. No effect on discolored length was found by vapor of acetone, methanol or trichloroethylene.

Acetates↗
PubMed1992

A new tetracycline antibiotic with antitumor activity. II. The structural elucidation of SF2575.

The structure of a new antitumor antibiotic SF2575, has been determined by spectroscopic analyses of the antibiotic and its alkaline degradation products. The relative stereochemistry has been confirmed by X-ray crystallographic analysis. The antibiotic has a 2-naphthacenecarboxamide carbon skelton which is structurally related to the tetracycline antibiotics and it is unique by bearing C-glycoside, salicyclic acid and angelic acid moieties.

Antibiotics, Antineoplastic↗
PubMed1992

Protection of neonatal calves against fatal enteric colibacillosis by administration of egg yolk powder from hens immunized with K99-piliated enterotoxigenic Escherichia coli.

The protective effects of egg yolk powder prepared from hens vaccinated with heat-extracted antigens from K99-piliated enterotoxigenic Escherichia coli (ETEC) strain 431 were evaluated in a colostrum-fed calf model of ETEC-induced diarrhea caused by a heterologous strain (B44). The antibody powder was obtained by spray-drying the water-soluble protein fraction of egg yolks after removing the lipid and fatty components by precipitation with hydroxypropylmethylcellulose phthalate. A total of 16 colostrum-fed calves were studied to determine whether the orally administered antibody powder would prevent fatal bovine colibacillosis caused by a virulent ETEC strain. Clinical response of individual calves was monitored and evaluated in the context of these variables: fecal consistency score, intestinal colonization, weight loss, and mortality. Control calves that were treated with vehicle (milk with egg yolk powder from nonimmunized hens) had severe diarrhea and dehydration and died within 72 hours after infection was manifested. In contrast, calves fed milk containing egg yolk powder with antipili agglutinin titers of 1:800 and 1:1,600 had transient diarrhea, 100% survival, and good body weight gain during the course of the study. Results indicate that the orally administered egg yolk powder protected against ETEC-induced diarrhea in neonatal calves and that the protective components may have been the antibodies raised by vaccination of chickens against ETEC.

Animals↗
PubMed1991

[Determination of bromide ion concentration in urine using a head-space gas chromatography and an ion chromatography--biological monitoring for methyl bromide exposure].

A head-space gas chromatography (GC) and an ion chromatography coupled with a conductive detector (IC) were used to evaluate levels of bromide ion in urine. The GC method followed by methylation with dimethyl sulfate, showed higher accuracy (2.7% of relative standard deviation) and lower minimum detection limit (0.4 mg/l) compared to the IC procedure of those values which were 8.7% and 1.0 mg/l. The correlation coefficient between the analytical results of 15 urinary samples by the two methods was 0.793. The bromide ion concentrations detected in 36 urine samples of workers exposed to methyl bromide were averaged at 13.3 +/- 7.7 mg/l. The average bromide ion of the non-exposed group was 7.1 +/- 2.1 mg/l (n = 6). Exposed methyl bromide concentrations of workers were monitored with passive samplers during their work shifts (8 hr). No significant correlation between exposed methyl bromide and bromide ion concentrations in urine was observed.

Bromides↗
PubMed1991

Quality control program on biological monitoring by Japan Federation of Occupational Health Organizations.

Since 1980, the Japan Federation of Occupational Health Organizations has been conducting an external quality control survey for biological monitoring under a contract with the Ministry of Labour of the Japanese Government. The number of participating organizations has increased from 91 in 1980 to 179 in 1987. The items in the program were lead and free erythrocyte protoporphyrin concentrations in blood, and lead, coproporphyrin, delta-aminolevulinic acid, chromium, hippuric acid, methylhippuric acid, total trichloro-compounds, mandelic acid, and phenol concentrations in urine. Evaluation was based on a scoring system. The scores were on the slope of major axis for probable ellipse, the slope of regression line, square root of error mean square for regression, performance indices, and the difference between 'true' and observed values of each sample. There was a gradual improvement in the evaluation scores as a function of time. The improvement was paralleled by the adoption of modern analytical methods such as flameless atomic absorption spectrometry for blood-lead measurement and high-performance liquid chromatography for urinary hippuric acid determination in many participants. These methods are simple in operation and reliable in performance. It was considered very probable that the program promoted the adoption.

Environmental Monitoring↗
PubMed1991

Absorption of cadmium after a long-term oral administration of cadmium to dogs.

A long-term experiment using beagle dogs to investigate the absorption of cadmium was conducted. The dogs in the experimental groups were given a commercial diet and pelleted food containing 1, 3, 10, 50, and 100 mg of cadmium per day. The cadmium concentration in the blood increased continuously, gradually reaching a steady state following the administration of cadmium. The cadmium excreted daily in urine increased continuously. The cumulative excreted amount of cadmium in urine was calculated by using the trapezoidal rule based on the data of excretion of cadmium in urine. Then the absorbed fraction of administered cadmium was estimated on the basis of the relationship between the cumulative excreted amount of cadmium in urine and the cumulative administered dose of cadmium after the cadmium concentration in blood reached a steady state. The absorbed fraction of cadmium decreased with an increase in the administered dose of cadmium. A dose-dependent increase between the absorbed amount and the administered dose was observed.

Administration, Oral↗