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Biomedical subjects

S Iida

Publications and source records attributed to S Iida.

At least 469 records · Page 26Linked to original sources
PubMed1982

Conformational change accompanying transition of ADP-sensitive phosphoenzyme to potassium-sensitive phosphoenzyme of (Na+,K+)-ATPase modified with N-[p-(2-benzimidazolyl)phenyl]maleimide.

The addition of Mg2+ or ATP to (Na+,K+)-ATPase (EC 3.6.1.3) of pig kidney modified with a sulfhydryl fluorescent reagent N-[p-(2-benzimidazolyl)phenyl]maleimide simply reduced fluorescence in the presence of Na+; however, the addition of both ligands to the enzyme induced a reversible dynamic change. The direction of the change was dependent on the concentration of Na+ present. These dynamic changes in fluorescence intensity both in the presence of low and high concentrations of Na+ can be repeated by the re-addition of ATP but not by ADP. Addition of ouabain under the former condition stabilized the fluorescence at the highest level, but the addition of ouabain under the latter condition increased the fluorescence from the lowest to the highest level. The phosphoenzyme formed under the former condition was sensitive to K+ and insensitive to ADP while the phosphoenzyme formed under the latter condition was sensitive to ADP and insensitive to K+. The data indicate that the positive and negative fluorescence changes were induced by the formation of K+-sensitive phosphoenzyme and ADP-sensitive phosphoenzyme, respectively. N-Ethylmaleimide treatment partially inhibited the positive change without affecting the negative change. These data also indicate that the transition of ADP-sensitive phosphoenzyme to K+-sensitive phosphoenzyme accompanied the largest fluorescence intensity change which was examined during the hydrolysis of ATP. The data obtained from the tryptophan fluorescence of both the native and the modified enzyme suggest that the micro-environments of the tryptophan and the sulfhydryl residues are similar in the state of K+-sensitive phosphoenzyme but different in the state of ADP-sensitive phosphoenzyme.

Adenosine Diphosphate↗
PubMed1982

Forskolin potentiates adrenocorticotropin-induced cyclic AMP production and steroidogenesis in isolated rat adrenal cells.

Forskolin, a unique diterpene which directly activates the adenylate cyclase, stimulated production of both cyclic AMP and corticosterone in isolated rat adrenal cells, in vitro. This agent also potentiated the action of adrenocorticotropin and/or cholera toxin on cyclic AMP production and steroidogenesis at lower concentrations. It augmented both an early (cyclic AMP production) and a late (steroidogenesis) action of the hormone in the adrenal gland.

Adrenal Glands↗
PubMed1982

The effect of chronic habitual alcohol intake on the development of liver cirrhosis and hepatocellular carcinoma: relation to hepatitis B surface antigen carriage.

To study the effects of habitual alcohol intake on the latency period for the development of liver cirrhosis and hepatocellular carcinoma (HCC), 158 patients with cirrhosis and 79 with HCC were analyzed with respect to age at the time of diagnosis. They were classified into four groups based on hepatitis B surface antigen (HBsAg) in serum, and the history of intake of more than one small bottle of Japanese "sake" or an equivalent per day for more than 10 years. The average age of HBsAg positive male cirrhotics with a drinking habit (n = 10) was 38.8 years, 10.5 years younger than that of those without a drinking habit (n = 8) (P less than 0.05). The average age of HBsAg negative cirrhotics with a drinking habit (n = 97) was 47.9 years, eight years younger than that of those not drinking (n = 36) (P less than 0.001). There was no significant difference in the laboratory data between these groups. The average age of the HBsAg positive HCC patients with a drinking habit (n = 20) was 48.9 years, nine years younger than that of those without a drinking habit (n = 12) (P less than 0.05). The average age of HBsAg negative male HCC cases with habitual intake of more than 126 ml of ethanol per day was 51.0 years (n = 8), ten years younger than that of nondrinking male HCC cases (n = 11) (P less than 0.05). These data suggest that habitual alcohol intake may promote the development of liver cirrhosis and HCC, especially in HBsAg carriers.

Adult↗
PubMed1982

A site-specific, conservative recombination system carried by bacteriophage P1. Mapping the recombinase gene cin and the cross-over sites cix for the inversion of the C segment.

The bacteriophage P1 genome carries an invertible C segment consisting of 3-kb unique sequences flanked by 0.6-kb inverted repeats. With insertion and deletion mutants of P1 derivatives the site-specific recombinase gene cin for C inversion) has been mapped adjacent to the C segment and the cix sites (for C inversion cross-over) have been located at the outside ends of the inverted repeats. Inversion of the C segment functions as a biological switch and controls expression of the gene(s) responsible for phage infectivity carried on the C segment. The cin gene product can promote recombination between a 'quasi- cix ' site on plasmid pBR322 and a cix site on P1 DNA. The junctions formed on the resulting co-integrate can also serve as cix sites. This observation implies a potential evolutionary process to bring genes under the control of a biological switch acting by DNA inversion.

Base Sequence↗
PubMed1982

Migration of Merkel cells in the labial mucous epithelium of adult rabbits following mental nerve resection.

Merkel cells in the lower labial mucosa of adult rabbits were studied electron microscopically, 9, 21, 28, and 50 days after resection of the mental nerves. By day 9, nerve fibers were completely retracted from the epithelial layer of the mucosa. On and after day 21, Merkel cells were located not only in the basal layer but also in the prickle or more superficial cell layers. The ultrastructure of the migrating Merkel cells was unchanged, both as to the amount and location of the specific cored granules in the cytoplasm, until the cells reached the granular cell layer. The position of the migrating Merkel cells differed from cell to cell, and migration continued for at least 50 days. A remarkably large number of immature Merkel cells was observed in the basal and suprabasal cell layers of the denervated epithelium even by day 50. Therefore, the possibility of the reproduction of Merkel cells exists. The migrating Merkel cells, as well as the keratinocytes in the same cell layer, had degenerated drastically in the parakeratinized cell layer. This seems to indicate that the Merkel cells belong to the line of keratinocytes.

Animals↗
PubMed1982

The catabolite-sensitive promoter for the chloramphenicol acetyl transferase gene is preceded by two binding sites for the catabolite gene activator protein.

DNase I protection experiments have indicated that the cyclic AMP-catabolite gene activator protein complex binds to two regions preceding the chloramphenicol acetyl transferase (cat) gene in Escherichia coli. One of these lies adjacent to the RNA polymerase binding site, whereas the second lies approximately 130 base pairs upstream from the starting point of transcription. Additional DNase protection experiments and in vitro transcription experiments with modified templates indicate that the catabolite gene activator protein site proximal to the cat promoter functions independently of the distal site, indicating that in vitro the second of these sites is not required for transcriptional activation of the cat gene.

Acetyltransferases↗
PubMed1982

Occurrence and properties of composite transposon Tn2672: evolution of multiple drug resistance transposons.

We found Tn2671 (the 23-kb long IS1-flanked r-determinant of NR1-Basel) inserted into the ampicillin resistance gene bla of the Tn3-related transposon Tn902. The resulting 28-kilobase-long composite transposon Tn2672 (= Tn902 bla::Tn2671) is stable, and it translocates as a unit into various loci including IS1 of the resistance transfer factor of R100-1. These results are discussed with respect to the evolution of R plasmids providing multiple drug resistance.

Anti-Bacterial Agents↗
PubMed1982

Presence of adrenocorticotropin-potentiating activity in a calcitonin preparation derived from porcine thyroid glands.

A calcitonin preparation derived from porcine thyroid glands exhibited potentiating activity on the steroidogenic action not only on ACTH-(1-24) but also of ACTH-(1-18) in isolated rat adrenal cells in vitro. This activity was demonstrated in various molecular weight fractions resulting from gel filtration of the preparation. This preparation also contained minute amount of immunoreactive and biologically active ACTH.

Adrenocorticotropic Hormone↗
PubMed1982

Inhibition of nitroblue tetrazolium reduction by metallothionein.

Metallothionein inhibited in a concentration-dependent fashion the reduction of nitroblue tetrazolium [NBT] mediated by xanthine oxidase and by NADH-phenazine methosulfate. This catalytic activity of metallothionein for dismutation of O2- is dependent on the copper content in metallothionein.

Animals↗