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Biomedical subjects

M Moriya

Publications and source records attributed to M Moriya.

At least 91 records · Page 5Linked to original sources
PubMed1986

Oil droplets of the retinal epithelium of the rat.

Oil droplets are observed in the retinal pigment epithelium (RPE) of both light- and dark-adapted rats. The accumulation of these droplets is strongly correlated with the clearance of large phagosomes that are found on a circadian basis in the RPE. Although strongly correlated with phagosomes in this way, the composition of the oil droplets does not resemble the lipid composition of rod outer segments (ROS). The important differences are that most of the 18:0 fatty acid (stearic) and virtually all of the polyunsaturated ones (principally docosahexaenoic, 22:6) are absent from the droplets. The major (greater than 95%) constituents of the droplets are triglycerides admixed with small amounts of vitamin A esters (less than 5%). This result suggests that certain of the ROS lipids, especially the polyunsaturated fatty acids, are cleared quickly from the RPE and are, perhaps, recycled to the neural retina. Such a process would account for the known ability of the retina to conserve the polyunsaturates despite dietary deficiencies.

Adaptation, Ocular↗
PubMed1985

Force-velocity characteristics of stomach muscle: a comparison between longitudinal and circular muscle strips.

The longitudinal and circular muscle preparations from guinea pig stomach were compared in their property of shortening. The highest shortening speed was attained only for about 1 sec for longitudinal muscle and about 2 sec for circular muscle from the onset of stimulation in the course of tetanic contraction. Dynamic constants calculated from a force-velocity curve were almost independent of the muscle length, being set near its optimum length. Mean dynamic constants of the longitudinal muscle were: Vmax: 0.205 L/sec, b: 0.056 L/sec, a/Po: 0.292 and that of the circular muscle were: Vmax: 0.576 L/sec, b: 0.056 L/sec, a/Po: 0.107. The difference in Vmax of these muscles are discussed along with the difference in ultrastructure of the contractile filaments.

Animals↗
PubMed1984

The application of scanning transmission electron microscopy (STEM) to the study of thin anodic films on nickel and nickel-molybdenum alloys.

Anodized thin-film samples of nickel, molybdenum and a nickel-13 w/o molybdenum alloy have been analysed by scanning transmission electron microscopy, using selected area diffraction, microdiffraction and X-ray micro-analysis. Thin-film samples were obtained by ion thinning with argon and by electropolishing in acetic acid-perchloric acid. Electropolishing is the preferred technique for these studies, producing a surface with roughness on a scale of 1 nm. The anodized films on nickel and nickel 13 w/o molybdenum alloy exhibit a rugosity with a 'particle' size of 3 nm. The crystal structure of the films is similar to f.c.c. nickel oxide. Molybdenum enrichment was detected in the anodized alloy surfaces but there is no electron diffraction evidence for a crystalline molybdenum oxide. The electron diffraction pattern from anodized pure molybdenum suggests that the surface film is amorphous.

Alloys↗
PubMed1983

Analysis of the antimutagenic effect of cinnamaldehyde on chemically induced mutagenesis in Escherichia coli.

The antimutagenic effect of cinnamaldehyde on mutagenesis was investigated using ten kinds of chemical mutagen in Escherichia coli WP2s (uvr A-). In addition, the frequency of mutation induction by each mutagen in an SOS repair deficient (umuC-) strain was compared with that in a wild-type (umuC+) strain. Cinnamaldehyde greatly suppressed the umuC-dependent mutagenesis induced by 4-nitroquinoline 1-oxide (4-NQO), furylfuramide or captan. However, cinnamaldehyde was less effective against the umuC-independent mutagenesis by alkylating agents such as N-methyl-N'-nitro-N-nitrosoguanidine and ethylmethanesulfonate. On the other hand, no inhibitory effect of cinnamaldehyde was observed on prophage induction or tif-mediated filamentous growth. These results suggest that a cinnamaldehyde does not prevent the induction of the SOS functions. Despite the decrease in the number of revertants, a remarkable increase was observed in the survival of 4-NQO-treated WP2s cells after exposure to cinnamaldehyde. The reactivation of survival suggests the promotion of some DNA repair system by cinnamaldehyde. This enhancement of survival was also observed in uvr B, polA, recF or umuC mutants and less in lexA or recB, C mutants. However, it was not observed in recA mutants. Therefore, we assume that cinnamaldehyde may enhance an error-free recombinational repair system by acting on recA-enzyme activity.

4-Nitroquinoline-1-oxide↗
PubMed1983

Antimutagenic effects of cinnamaldehyde on chemical mutagenesis in Escherichia coli.

Antimutagenic effects of cinnamaldehyde on mutagenesis by chemical agents were investigated in Escherichia coli WP2 uvrA- trpE-. Cinnamaldehyde, when added to agar medium, greatly reduced the number of Trp+ revertants induced by 4-nitroquinoline 1-oxide (4-NQO) without any decrease of cell viability. This antimutagenic effect could not be explained by inactivation of 4-NQO caused by direct interaction with cinnamaldehyde. Mutagenesis by furylfuramide (AF-2) was also suppressed significantly. Mutations induced by methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) were slightly inhibited. However, cinnamaldehyde was not at all effective on the mutagenesis of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Two derivatives of cinnamaldehyde, cinnamyl alcohol and trans-cinnamic acid, did not have as strong antimutagenic effects on 4-NQO mutagenesis as cinnamaldehyde had. Because cinnamaldehyde showed marked antimutagenic effects against mutations induced by UV-mimic mutagens but not those induced by MNNG or EMS, it seems that cinnamaldehyde might act by interfering with an inducible error-prone DNA repair pathway.

4-Nitroquinoline-1-oxide↗
PubMed1983

Further mutagenicity studies on pesticides in bacterial reversion assay systems.

A total of 228 pesticides (88 insecticides, 60 fungicides, 62 herbicides, 12 plant-growth regulators, 3 metabolites and 3 other compounds) was tested for mutagenicity in bacterial reversion-assay systems with 5 strains (TA100, TA98, TA1535, TA1537 and TA1538) of Salmonella typhimurium and a strain (WP2 hcr) of Escherichia coli. 50 pesticides (25 insecticides, 20 fungicides, 3 herbicides, 1 plant-growth regulator and 1 other compound) were found to be mutagenic. 5 of them required metabolic activation (S9 mix) for their activities. Among various chemical groups, organic phosphates, halogenated alkanes and dithiocarbamates showed higher ratios of mutagens. Although 22 of the pesticides tested have been reported to be carcinogenic, 7 of them, i.e., captain, DBCP, EDB, EDC, ETU, HEH and nitrofen, were detected as mutagens in the present assay. Most of the other 15 non-mutagenic carcinogens were organochlorine pesticides such as alpha-BHC, chlorobenzilate, p,p'-DDT, dieldrin and quintozene.

Carcinogens↗
PubMed1982

Induction of sex-linked recessive lethal mutations in Drosophila melanogaster males by gaseous 1,2-dibromo-3-chloropropane (DBCP).

Acute exposure to gaseous 1,2-dibromo-3-chloropropane (DBCP) caused sex-linked recessive lethal mutations in Drosophila melanogaster males. Brood pattern analysis showed that spermatids and spermatocytes were more sensitive to the lethal-mutation induction by DBCP than were spermatogonia. The mutation induction was not observed in the stage of spermatozoa.

Animals↗
PubMed1982

The differences in contractile response to AC field stimulation between longitudinal and circular muscles of guinea pig stomach.

Contractile response to AC field stimulation was compared between the longitudinal and circular muscles of the guinea pig stomach under various stimulating conditions. The longitudinal muscle responded with considerable tension at any frequency between 20 and 2,000 Hz. The circular muscle showed a peak response around 200 Hz with rapidly decreasing response to the higher frequencies of less than 800 Hz. Experiments in the presence of tetrodotoxin and atropine revealed that the circular muscle was scarcely stimulated directly (without nerve excitation) by the AC, while the longitudinal muscle was stimulated directly at frequencies higher than 400 Hz, as well as being stimulated indirectly at frequencies lower than 200 Hz. The field strength necessary to generate one-half maximum tension was higher in the circular muscle (2.8 V/cm) than in the longitudinal muscle (1.5 V/cm at 200 Hz), although when a frequency lower or higher than 200 Hz was applied, the strength-tension curve shifted to the left or right, respectively. The contractile responses of the two muscles were graded with respect to filed duration up to maximum tension. The maximum tension and the highest rate of tension development were given at the stimulating condition of 200 Hz, 5 V/cm, for 5 sec in both types of muscles. The maximum tension generated per unit cross-sectional area of the longitudinal muscle was 19.2 g/mm2 and that of the circular muscle was 32.5 g/mm2. The maximum rates of tension development of the longitudinal and circular muscles wer 9.1 and 12.1 g/(mm2 . sec), respectively.

Animals↗
PubMed1980

Detection of mutagenicity of procarbazine by the host-mediated assay with polychlorinated biphenyl (aroclor 1254) as enzyme inducer.

Procarbazine [N-isoppropyl-alpha-(2-methylhydrazino)-p-toluamide] was tested for mutagenicity with Salmonella typhimurium G46 in the host-mediated assay by using male BALB/c mice pretreated orally with polychlorinated biphenyl (PCB, Aroclor 1254). Procarbazine was weakly mutagenic without PCB pretreatment, but the pretreatment greatly enhanced the mutagenicity of this compound. The administration of 500 mg PCB/kg 1 day before procarbazine dosage was suitable for the detection of the mutagenicity. Among PCB, 3-methylcholanthrene (3-MC) and phenobarbital sodium (PB), the former 2 inducers showed much stronger enhancing effects than PB. The pretreatment with 3-MC in combination with PB did not cause further enhancement compared with 3-MC alone.

Animals↗
PubMed1980

Sister-chromatid exchanges and chromosomal aberrations in cultured Chinese hamster cells treated with pesticides positive in microbial reversion assays.

The induction of sister-chromatid exchanges (SCEs), chromosomal aberrations and polyploids was investigated in cultured Chinese hamster cells treated with pesticides or a related compound positive in microbial reversion assays. The chemicals tested were captan, captafol, 1,2-dibromoethane (EDB), 1,2-dibromo-3-chloropropane (DBCP), 5-nitro-1-naphrhonitrile (NNN), p-dimethylaminobenzenediazo sodium sulfonate (DAPA), 2-hydrazinoethanol (HEH), vamidothion, dichlorovos (DDVP), N-nitroso-ethylenethiourea (N-nitroso-ETU), and 2,4-dinitrophenyl thiocyanate (NBT). A significant and dose-dependent increase in the frequency of SCEs and chromosomal aberrations was observed in the cell cultures treated with captan, captafol, EDB, DBCP, HEH, DDVP, vamidothion, DAPA or N-nitroso-ETU or NBT produced a significant increase in the frequency of polyploid cells, whereas the other agents did not. When compared with results from microbial reversion assays, a close correlation was observed between the ability to induce SCEs or chromosomal aberrations and the mutagenic potency in bacteria (r:0.71-0.84).

Aneuploidy↗
PubMed1980

Mutagenicity screening of feed additives in the microbial system.

18 feed additives were tested for DNA-modifying effects by the repair test named "rec-assay" with Bacillus subtillis H17 (rec+) and M45 (rec-), and for mutagenicity with Escherichia coli WP2 hcr and 5 Salmonella typhimurium tester strains with the use of a top-agar overlay method. Carbadox, furazolidone, panazon and zoalene were positive in both assays. The former 3 were mutagenic for TA100, TA98 and WP2 hcr, while zoalene was mutagenic for all strains. These 4 compounds did not require a metabolic activation for their mutagenic activities. Nicarbazin was weakly mutagenic for TA1538 and TA98 with and without S9 mix. Amprolium and caprylohydroxamic acid also showed very weak mutagenicities only for TA100 with S9 mix and for WP2 hcr with and without S9 mix, resp. The mutagenic activities of carbadox, furazolidone and panazon for TA100 were reduced only by the addition of S9 mix, but not by S9 fraction or blood, whereas that of zoalene was decreased by any of the 3 factors.

Animal Feed↗
PubMed1979

Structural analysis of functionally different smooth muscles.

The ultrastructure of the longitudinal and circular muscle cells of the guinea pig stomach which show different contractile responses was compared. The extracellular space within the muscle bundles is about 12.1% in the longitudinal layer and about 4.4% in the circular layer. Nexuses were sonsistently found in the circular muscle layer but not in the longitudinal muscle layer. Numbers of both mitochondria and microtubules per unit area of smooth muscle cell are larger in the longitudinal than in the circular muscle. Cellular area occupied by sarcoplasmic reticulum is about 4.7% in the longitudinal muscle, 2.3% in the circular muscle. The numbers of caveolae are almost the same in both tissues. The most distinct difference between the two types of smooth muscle is the appearance of the thick filaments. The circular muscle cell contains approximately 50 thick filaments per 0.5 micron 2 of cytoplasmic area, while the longitudinal muscle cell only about 25 filaments which were usually much thinner than those of the circular muscle. These results indicate that the contractile apparatus itself is different in longitudinal and circular smooth muscles of the guinea pig stomach.

Animals↗
PubMed1979

Inhibitors for the mutagenicities of colon carcinogens, 1,2-dimethylhydrazine and azoxymethane, in the host-mediated assay.

Inhibitory effects of several chemicals on the mutagenicities of 1,2-dimethylhydrazine (DMH) and azoxymethane (AOM) for Salmonella typhimurium G46 in the host-mediated assay were investigated. They were carbon disulfide (CS2), tetraethylthiuram disulfide (disulfiram, DSF), sodium diethyldithiocarbamate (SDDC), ethylene-bis(dithiocarbamato) manganese (Maneb), pyrazole (PZ), aminoacetonitrile hydrogen sulfate (AAN), and sodium selenite (SE). All the compounds, except for SE, inhibited the mutagenicities of DMH and AOM.

Aminoacetonitrile↗
PubMed1979

Carcinogenicity of N-nitroso-ethylenethiourea in female mice.

The nitrosation product of ethylenethiourea (ETU), N-nitroso-ETU, was tested for tumorigenicity in female ICR mice. Ten weekly oral administrations of this compound (0.66-2.64 mg/dose) caused apparently dose-dependent increases in the number of mice with pulmonary and lymphocytic neoplasms.

Animals↗
PubMed1979

Assay for mutagenicity of bile in Sprague-Dawley rats treated subcutaneously with intestinal carcinogens.

To investigate the mode of action of sc injected intestinal carcinogens, the mutagenicity assay of bile collected from noninbred Sprague-Dawley rats treated sc with carcinogens was conducted in the presence and absence of beta-glucuronidase. The bile samples from rats inoculated with 4-aminobiphenyl were mutagenic for Salmonella typhimurium TA100 only in the presence of beta-glucuronidase, whereas those from the 3,2'-dimethyl-4-aminobiphenyl-treated rats did not require the enzyme for mutagenicity toward strain TA100. On the contrary, the assays with S. typhimurium G46 and TA100 of bile from rats inoculated with 1,2-dimethylhydrazine, azoxymethane, or methylazoxymethanol acetate failed to reveal mutagenicity whether beta-glucuronidase was added or not, though these carcinogens were highly mutagenic for strain G46 in the Salmonella-microsome mutagenicity test and/or in the host-mediated assay.

Animals↗