Acceleration of DNA synthesis in post-hepatectomized regenerating liver of normal rat by insulin and glucagon

The effect of insulin and/or glucagon on the cumulative incorporation of tritiated thymidine was studied using normal rats with post-hepatectomized regenerating livers. Although the cumulative incorporation value was low at 20 hr and increased thereafter, a significant difference was not found between control and treated rats up to 60 hr after the operation. However, when rats were distributed according to the time the incorporation reached a maximum, there was a significant difference in the distributions between control rats and rats treated with combined insulin and glucagon (P=0.0303); more rats showed maximum incorporation at earlier times after treatment. These results suggest that a combination of the two hormones accelerates DNA synthesis in post-hepatectomized regenerating liver of normal rats.     

A survey of Brucella canis infection in dogs sheltered in Tohoku University School of Medicine (author's transl)]

A total number of 1549 dogs from Miyagi Prefecture and the north coast area of Fukushima Prfecture were surveyed during a year from December 1976 to November 1977 for Brucella canis (B. canis). 173 of 1549 dogs (11.2%) were sero-positive to B. canis, and B. canis was isolated from 55 of 148 dogs examined, giving more than 3.6% for total 1549 dogs. The positivity were higher than that have been reported from other areas. The results of the morphological and biochemical studies for isolates were similar to the reference strain RM6/66, and they were identified as B. canis. No significant difference in sero-positive rate was found between male and female, but isolation rate was higher in female than in male. B. canis was isolated most frequently from the uterus and the spleen of both sexes. The importance of urine and milk as a source of infection was discussed as well as the role of infected focus at non gravid uterus for abortion and fetal infection. A case supposed to be a vertical infection was described also.     

Nucleotide Sequencing Analysis of the 146-Kilobase Segment around theIkBLandMICAGenes at the Centromeric End of the HLA Class I Region

To elucidate the complete gene structure and to identify new genes involved in the development ofHLAclass I antigen-associated diseases in the class I region of the human major histocompatibility complex on chromosome 6, a YAC clone (745D12) covering the 146-kb segment around theIkBLandMICAloci was isolated from a YAC library constructed from the B-cell line, BOLETH. A physical map of this region was constructed by isolation of overlapping cosmid clones derived from 745D12. Of these, five contiguous cosmids were chosen for DNA sequencing by the shotgun strategy to give a single contig of 146,601 bp from 2.8 kb telomeric of theIkBLgene to exon 6 ofMICA.This region was confirmed to contain five known genes,IkBL, BAT1, MICB, P5-1,andHLA-X(class I fragment), from centromere to telomere, and their exon–intron organizations were determined. The3.8-1homologue gene (3.8-1-hom) showing 99.7% identity with the3.8-1cDNA clone, which was originally isolated using the 3.8-kbEcoRI fragment between theHLA-54/Hand theHLA-Ggenes, was detected betweenMICAandMICBand was suggested to represent the cognate3.8-1genomic sequence from which the cDNA clone was derived. No evidence for the presence of expressed new genes could be obtained in this region by homology and EST searches or coding and exon prediction analyses. One TA microsatellite repeat spanning 2545 bases with as many as 913 repetitions was found on the centromeric side of theMICAgene and was indicated to be a potential hot spot for genetic recombination. The two segments of approximately 35 kb upstream of theMICAandMICBgenes showed high sequence homology (about 85%) to each other, suggesting that segmental genome duplication including theMICAandMICBgenes must have occurred during the evolution of the humanMHC.     

Purification, characterization and molecular cloning of tyrosinase from the cephalopod mollusk, Illex argentinus.

Tyrosinase (monophenol, L-DOPA:oxygen oxidoreductase) was isolated from the ink of the squid, Illex argentinus. Squid tyrosinase, termed ST94, was found to occur as a covalently linked homodimeric protein with a molecular mass of 140.2 kDa containing two copper atoms per a subunit. The tyrosinase activity of ST94 was enhanced by proteolysis with trypsin to form a protein, termed ST94t, with a molecular mass of 127.6 kDa. The amino acid sequence of the subunit was deduced from N-terminal amino acid sequencing and cDNA cloning, indicating that the subunit of ST94 is synthesized as a premature protein with 625 amino acid residues and an 18-residue signal sequence region is eliminated to form the mature subunit comprised of 607 amino acid residues with a deduced molecular mass of 68,993 Da. ST94 was revealed to contain two putative copper-binding sites per a subunit, that showed sequence similarities with those of hemocyanins from mollusks, tyrosinases from microorganisms and vertebrates and the hypothetical tyrosinase-related protein of Caenorhabditis elegans. The squid tyrosinase was shown to catalyze the oxidation of monophenols as well as o-diphenols and to exhibit temperature-dependency of o-diphenolase activity like a psychrophilic enzyme.     

A simple method for sutureless gastrointestinal anastomosis in rat.

A simple tubing stent was attempted to test a model for sutureless gastrointestinal anastomosis in 6 male rats at the age of 15 weeks. In the 3rd and 4th weeks after the operation, X-ray examination demonstrated that the gastrointestinal passage in the anastomotic site was quite satisfactory. There was no incidence of anastomotic leakage. In the 6th week after the operation, there were no macroscopic or microscopic ruptures, nor were there any obstructions at the anastomotic site. This simple sutureless method was effective at preparing anastomosis in the gastrointestinal tract in the rat and could be applied to other small experimental animals.     

Effects of metal ions on 15-hydroxy prostaglandin dehydrogenase activity in rabbit kidney cortex

The effects of Cu2+, Fe2+ and Zn2+ on 15-hydroxy prostaglandin dehydrogenase activity in rabbit kidney cortex were examined. Cu2+ and Zn2+ (0.05-0.5 mM) inhibited the activity of this enzyme in a dose-dependent manner. The concentration required for 50% inhibition was approximately 0.1 mM for Cu2+ and 0.15 mM for Zn2+. The inhibition by both metals was uncompetitive and non-competitive with regard to NAD+ and prostaglandin E2, respectively, indicating that the mechanisms of the inhibition on the enzyme of both metals may be the same. Fe2+ had no effect on the activity of this enzyme. These results suggest that Cu2+ and Zn2+ have the potential to modulate the catabolism of prostaglandins by the kidney cortex.     

Pharmacological differentiation of epithelium-derived relaxing factor from nitric oxide

We examined the possibility that nitric oxide is one of the epithelium-derived relaxing factors in guinea pig airways. First we studied whether nitric oxide could relax isolated tracheal strips, and then we examined the effects of known inhibitors of endothelium-dependent relaxation (EDR) in the vascular system [hemoglobin, methylene blue, and NG-monomethyl-L-arginine (L-NMMA)] on epithelium-dependent relaxation (EpDR) induced by hyperosmotic stimuli in perfused whole tracheal preparations. Mannitol (160 mM in Krebs-Henseleit solution) applied to the epithelial surface was used as an osmotic stimulus to induce EpDR after carbachol-induced contraction (2 microM, serosal side). Nitric oxide produced concentration-dependent and complete relaxation of epithelium-denuded tracheal strips. Preincubation of the whole trachea with hemoglobin significantly inhibited osmotic-induced EpDR (P less than 0.05), but preincubation with methylene blue and L-NMMA did not. Hemoglobin introduced into the epithelial side after EpDR induced by hyperosmotic stimuli reversed relaxation, but methylene blue and L-NMMA did not. These results suggest that, although EpDR and vascular EDR have some pharmacological similarities and nitric oxide can relax airway smooth muscle, nitric oxide is not responsible for osmotic-induced EpDR.     

Induction of peroxisomal beta-oxidation enzymes by dehydroepiandrosterone and its sulfate in primary cultures of rat hepatocytes.

Treatment of cultured rat-hepatocytes with 50 microM dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) for up to 5 days resulted in a progressive increase in peroxisomal beta-oxidation and carnitine acetyltransferase activity. After 5 days, the increases in activity were 2.6- and 4.8-fold for peroxisomal beta-oxidation and 11.7- and 17.1-fold for carnitine acetyltransferase over the initial activity, in DHEA- and DHEAS-treated cells, respectively. The stimulation of the activity of these enzymes by the respective agents was dose-related; it was maximum with 50 to 100 microM DHEA and 50 to 250 microM DHEAS, although DHEAS was more effective for stimulation than DHEA. Western blot analyses revealed the induction of acyl-CoA oxidase, enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme and carnitine acetyltransferase in the treated cells. Moreover, induction of fatty acid omega-hydroxylase proteins (P-450IVAS) was also revealed. These results indicate that DHEA and DHEAS act directly on hepatocytes. The induction of hepatic peroxisomal beta-oxidation enzymes and several other enzymes in rats administered with DHEA could be accounted for, at least in part, by the direct action of DHEA and its sulfate-conjugate (DHEAS) on liver cells.     

Complete amino acid sequence of an immunomodulatory protein, ling zhi-8 (LZ-8). An immunomodulator from a fungus, Ganoderma lucidium, having similarity to immunoglobulin variable regions

The complete amino acid sequence of a novel immunomodulatory protein, ling zhi-8 (LZ-8), isolated from a fungus, Ganoderma lucidium (Kino, K., Yamashita, A., Yamaoka, K., Watanabe, J., Tanaka, S., Ko, K., Shimizu, K., and Tsunoo, H. (1989) J. Biol. Chem. 264, 472-478), was determined by protein sequencing. The polypeptide consists of 110 amino acid residues with an acetylated amino end and has a molecular mass of 12,420 Da including an amino-end blocking group. There is no attachment site for an Asn-linked oligosaccharide chain, consistent with the very low carbohydrate content of LZ-8. These results indicate that the native form of LZ-8 with a molecular mass of 24 kDa is a homodimer of the LZ-8 polypeptide whose sequence is described here. Furthermore, the LZ-8 chain shows considerable similarity to the variable region of immunoglobulin heavy chain both in its sequence and in its predicted secondary structure. The interesting possibility that LZ-8 is related to an ancestral protein of the immunoglobulin superfamily is also discussed.     

Partial trisomy of the distal segment of 14q

Summary The case of a male infant with duplication of the distal segment of chromosome 14q is described. There was an extra chromosomal segment at the distal end of the long arm of chromosome 17. Banding techniques suggested that the extra segment might be the distal segment of chromosome 14q. DNA analysis using probes from distal 14q as well as from other parts of the genome confirmed that the extra segment consisted of the distal part of 14q. Both the proband's parents and his elder sister had normal karyotypes.