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Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 1,531 records · Page 85Linked to original sources
PubMed1982

Induction of delta-aminolevulinic acid synthase and delta-aminolevulinic acid dehydratase in normal human bone marrow cultures.

Activities of delta-aminolevulinic acid (ALA) synthase and ALA dehydratase, the first and the second enzymes of the heme biosynthetic pathway, were determined in erythroid colonies derived from normal human bone marrow in culture. ALA synthase and ALA dehydratase were induced when normal human bone marrow cells were incubated in the presence of erythropoietin (Ep) in culture, and the extent of induction of ALA synthase as well as ALA dehydratase was dependent on Ep concentrations and culture periods. Both ALA synthase and ALA dehydratase were increased in cultured erythroid cells before the appearance of morphologically recognizable hemoglobinized colonies, corroborating the sequential induction of heme biosynthetic pathway enzymes in human bone marrow erythroid cells.

5-Aminolevulinate Synthetase↗
PubMed1981

Human neutrophil swelling induced by immune complexes and aggregated IgG.

Using a Coulter counter method, the effects of various types of IgG-dependent phagocytic stimuli on human neutrophil (PMN) swelling were determined. Human heat aggregated IgG, ovalbumin-antiovalbumin (OV-anti-OV) immune complexes, and opsonized latex particles all induced PMN swelling. The OV-anti-OV immune complexes were effective, whether prepared at antigen-antibody equivalence (insoluble) or at 4 or 9 times antigen excess (soluble). Swelling of PMN occurred at 37 degrees C, but not at 4 degrees C. Complement was not present in any of the experiments. In contrast to the above results, native IgG, OV-anti-OV F(ab')2 immune complexes and unopsonized latex particles did not induce PMN swelling. These results suggest that the PMN swelling observed in this study is due to Fc-dependent, complement-independent membrane stimulation and/or phagocytosis.

Antigen-Antibody Complex↗
PubMed1981

Immobilization osteoporosis and active vitamin D: effect of active vitamin D analogs on the development of immobilization osteoporosis in rats.

The therapeutic effects of vitamin D analogs, 1,24(R)-dihydroxycholecalciferol [1,24(R)-(OH)2D3], 1,24(S)-dihydroxycholecalciferol [1,24-(S)(OH)2D3], and 1,25-dihydroxycholecalciferol [1,25(OH)2D3] on immobilization osteoporosis were studied in rats. The right hind limb was immobilized through application of a plaster cast following the section of the sciatic nerve. The left hind limb was intact. Vitamin D analogs were orally administered for 6 weeks at dose levels of 0.02 and 0.10 micrograms/kg/day, respectively. The mean lengths of the immobilized femurs were not significantly different from those of the intact femurs in all the experimental groups. In the immobilized femur of animals treated with 1,24(R)(OH)2D3, 0.10 micrograms/kg, dry and ash weights were heavier and calcium and phosphorus contents greater than those in the nontreated group. Furthermore, the amount of calcified bone mass and the cortical thickness of the femurs of the immobilized limb in 1,24(OH)2D3-treated animals were greater than those in the nontreated animals. Treatment with 1,25(OH)2D3 at 0.10 micrograms/kg caused an increase of the bone mass in both immobilized and intact femurs when compared with those of the control group. It was concluded that the administration of 1,24(R)(OH)2D3 diminished the effect of immobilization in the development of osteoporosis without any side effects.

Animals↗
PubMed1981

Developmental changes in the collagens and some collagenolytic activities in bovine dental pulps.

Collagen concentration was fairly low in young bovine 3rd premolar pulps, about 9 per cent by dry weight of pulp in stage I, but it increased consistently up to more than 25 per cent at stage V as the pulp matured. The ratio of type III to type I collagen similarly increased from 13 per cent at stage I to 32 per cent at stage V. Both collagenase and possibly collagenolytic neutral peptidases showed significantly high activity in the early stage of pulp development where the rate of collagen synthesis was also elevated. Higher rates of both collagen synthesis and its degradation might explain the low concentration and content in the early stage of pulp development.

Aging↗
PubMed1981

Antibody coating of liposomes with 1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimide and the effect on target specificity.

Liposome surfaces were modified with normal rabbit IgG or rabbit anti-sheep erythrocyte IgG by adsorption or by coupling with a water soluble cross-linking reagent, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDCI). Modification with normal IgG reduced the non-specific binding of the liposomes to erythrocytes. The immunological binding capacity of the immune IgG on liposomes was better for the chemically coupled preparation than for the adsorbed one. Complement dependent cytolytic activity of the immune IgG towards target erythrocytes was diminished as a consequence of liposome binding by either method, but to a lesser extent in the coupling method. Antibody coating by EDCI thus provides liposomes which can bind effectively to antigenic target cells.

Animals↗
PubMed1981

Studies on the mechanism of action of 1 alpha, 24-dihydroxyvitamin D3. II. Specific binding of alpha, 24-dihydroxyvitamin D3 to chick intestinal receptor.

The binding of vitamin D3 analogues to the chick intestinal cytosol receptor was studied. In intestinal cytosol fraction, receptor proteins having the sedimentation constant of 2.5 S and 3.7 S to which 1 alpha,25-dihydroxyvitamin D3 binds were present, and the latter was specific for the compound. The binding of 1 alpha,24(R)-dihydroxyvitamin D3 and 1 alpha,24(S)-dihydroxyvitamin D3 to the receptor was also observed, while very weak binding was seen in the case of 24(R)25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3. The binding affinity of 1 alpha,24(R)-dihydroxyvitamin D3 to the 3.7 S receptor was 1.3 times as high as that of 1 alpha,25-dihydroxyvitamin D3, whereas those of 1 alpha,24(S)-dihydroxyvitamin D3, 1 alpha-hydroxyvitamin D3 and 25-hydroxyvitamin D3 were 10, 304 and 652 times lower than 1 alpha,25-dihydroxyvitamin D3, respectively. The dissociation constant of the receptor-1 alpha,25-dihydroxyvitamin D3 complex at 0 degrees C was 3.0 x 10(-11) M, and the dissociation constants were calculated to be 2.4 x 10(-11) M and 2.7 x 10(-10) M for the complexes with 1 alpha,24(R)-dihydroxyvitamin D3 and 1 alpha,24(S)-dihydroxyvitamin D3, respectively.

Animals↗
PubMed1981

Selective induction of microsomal 2-acetylaminofluorene N-hydroxylation by dietary 2-acetylaminofluorene in rats.

Inbred male ACI/N rats were treated with an intermittent carcinogenic regimen of 2-acetylaminofluorene (2-AAF) until the development of hepatomas (40 weeks), and the activation of 2-AAF by liver S-9 and the oxidation of 2-AAF; and 2 other drugs by microsomal functions were periodically examined. The S-9 activity increased at the end of 1 feeding cycle (3 weeks 2-AAF diet and 1 week normal diet), reaching a maximum of 400% of controls after 2 or 3 feedings cycles. It then declined, but the elevated S-9 activity (300 to 250% of controls) was sustained until the development of hyperplastic nodules in the livers. The microsomal oxidation of 2-AAF to N-hydroxy-2-AAF was activated by dietary 2-AAF, but the activity of cytosol (S-105) to produce mutagen from N-hydroxy-2-AAF was not affected. Cytochrome P-450 content and microsomal oxidation of aminopyrine and aniline were gradually decreased below the normal levels by 2-AAF feeding, although microsomal p-hydroxylation of aniline was temporarily elevated to about 130% of control at the first or the second feeding cycle. These results indicate that dietary 2-AAF selectively induces microsomal 2-AAF N-hydroxylase which mediates the oxidation of 2-AAF to N-hydroxy-2-AAF, a proximate carcinogenic or mutagenic metabolite.

2-Acetylaminofluorene↗
PubMed1981

Pharmacological characteristics of abnormal behavior induced by harmine with special reference to tremor in mice.

Harmine, a hallucinogen with potent monoamine oxidase inhibitory properties, induced abnormal behavior, including tremor, scratching, head twitch and cage biting, in the mouse. A dose-dependent tremor was produced by all routes of administration of harmine. Although oxotremorine tremor was markedly suppressed by atropine, harmine tremor was unaffected by cholinergic drugs, remarkably inhibited by dopaminergic drugs, antidepressants and diazepam, mildly diminished by p-chlorophenylalanine, markedly augmented by 5-hydroxytryptophan and mildly increased by alpha-methyl-p-tyrosine. These findings suggest that a catecholaminergic (particularly dopaminergic) and serotonergic system imbalance plays an important role in the manifestation of harmine tremor. In view of these characteristics, harmine tremor may be useful as an effective experimental model for the evaluation of antiparkinsonism drugs, along with oxotremorine tremor because of the different mechanism of occurrence. In addition, harmine tremor appears to be useful in characterizing the properties of antidepressant drugs.

5-Hydroxytryptophan↗
PubMed1981

Increase of beta-glucuronidase activity in the serum of rats administered organophosphate and carbamate insecticides.

An approximately 50-fold increase in serum beta-glucuronidase activity appeared 2 hours after the administration of such organophosphate insecticides as dichlorvs, diazinon and disulfoton and of a carbamate insecticide, carbaryl. The activities of other acid hydrolases in the serum such as ribonuclease, acid phosphatase, hyaluronidase and N-acetylglucosaminidase did not change significantly after the insecticide treatment. The response was related to the dose level and was evident after a single intraperitoneal dose of diazinon as low as 1.6 mg/kg. This appearence of an increase in beta-glucuronidase was retarded by pretreatment with SKF 525A, an inhibitor of drug metabolizing enzyme. When beta-glucuronidase was elevated by a large dose of diazinon, full response to a second dose of diazinon did not occur until approximately one month after administration of the first dose.

Animals↗