Isolated tetrameric particles (166S) derived from the crystalline lattices known to appear in hypothermic chicken embryos consist of mature 80S ribosomes which contain all species of ribosomal RNA and a complete set of ribosomal proteins. Ribosome tetramers are not a special type of polysomes since in solutions of high ionic strengths (500 mM KCl and 50 nM triethanolamine-HCl buffer) containing 5 mM MgCl(2) they dissociate into 40S and 60S ribosomal subunits, without the need of puromycin, and at a concentration of Mg(++) higher than 3 mM they are not disassembled by mild RNase treatment. Tetramers spontaneously disassemble into 80S monomers when the Mg(++) concentration is lowered to 1 mM at relatively low ionic strength. Tetramers failed to couple in vitro puromycin-(3)H into an acid-insoluble product, indicating the lack of nascent polypeptide chains. Although tetramers have no endogenous messenger RNA activity, they can be programmed in vitro with polyuridylic acid (poly U) to synthesize polyphenylalanine. All ribosomes within a tetramer can accept poly U, without the need of disassembly of the tetramers into monomers or subunits.
We designed a cell-network-based full-custom test-chip for gray-scale/color image segmentation of real-time video-signals in 350nm CMOS technology. From this digital test-chip design, fully-integrated QVGA-size video-picture-segmentation chips, with 250/spl mu/sec segmentation time per frame, at 10MHz are estimated to become possible at the 90nm technology node.
Case 1 was an 85-year-old man, who was pointed out a gallbladder tumor by screening CT scan after bladder cancer. The tumor was arisen in the gallbladder body, 1 .5 cm in diameter. He underwent a radical surgery; the gallbladder-bed was resected with more than 1 cm margin, and lymphadenectomy was done preserving biliary tract. Pathologically his tumor was papillary adenocarcinoma suspected to invade to the liver-bed minimally. A lymph node involvement was solitary located at right side of hepatoduodenal ligament (behind biliary tract). Case 2 was a 73-year-old man who was pathologically diagnosed to be advanced gallbladder carcinoma after laparoscopic cholecystectomy. CT scan and MRI revealed a mass sized 2 cm in diameter, at the gallbladder-bed, and PET exam showed a hot spot at this site only. Therefore, he underwent a radical surgery like case 1. Pathologically the tumor was moderately differentiated adenocarcinoma, and a lymph node involvement was solitary and located behind a biliary tract. Both patients have been recurrent free for more than 22 months and 15 months, respectively. Two lymphatic drainage routes have been suggested, one is the route which runs right side of hepatoduodenal ligament, another runs via left side of the ligament, along hepatic artery. Our two cases are considered to be solitary metastatic cases along the right side route. A clinical case of solitary node positive seems to be known for its relatively good prognosis. In order to justify our cases, we need a longer follow-up period, or we should have more cases to be experienced.
The effects of thyroid hormone (T3) treatment on liver Na,K-adenosine triphosphatase (Na,K-ATPase) at the levels of subunit messenger RNA (mRNA), enzymatic activity, and enzyme content were studied in euthyroid rats injected for 5 consecutive days with T3. Northern and slot blot analyses of polyadenylated mRNA revealed that T3 treatment coordinately increases the level of mRNA encoding the alpha 1- and beta 1-subunits, approximately 4- and 3-fold, respectively, above basal levels. To determine whether this increase in the subunit mRNA consequently results in an increase in the synthesis of the enzyme, a modified liver cell fractionation procedure was developed, and the subcellular fractions from control and T3-treated livers were examined biochemically. Western blot analysis and Na,K-ATPase assay demonstrated that T3 treatment resulted in a 2-fold increase in both the amount and activity of the enzyme. Furthermore, the Western blot analysis of endoglycosidase-H-treated membrane fractions revealed an increase in the amount of the precursor beta-subunit in the T3-treated liver rough microsomal fraction, suggesting that an increase in subunit synthesis contributes at least partially to the increase in the rat liver Na,K-ATPase by T3 treatment.
We identified the phosphatidylinositol transfer protein (PITP) as being responsible for a powerful latent, nucleotide-independent, Golgi-vesiculating activity that is present in the cytosol but is only manifested as an uncontrolled activity in a cytosolic protein subfraction, in which it is separated from regulatory components that appear to normally limit its action to the scission of COPI-coated buds from trans-Golgi network membranes. A specific anti-PITP antibody that recognizes the two mammalian PITP isoforms fully inhibited the capacity of the cytosol to support normal vesicle generation as well as the uncontrolled vesiculating activity manifested by the cytosolic protein subfraction. The phosphatidylinositol- (PI) loaded form of the yeast PITP, Sec14p, but not the phosphatidylcholine- (PC) loaded form of the protein, was capable of substituting for the cytosolic subfraction in promoting the scission of coated buds from the trans-Golgi network. At higher concentration, however, Sec14p, when loaded with PI, but not with PC or phosphatidylglycerol, caused by itself an indiscriminate vesiculation of uncoated Golgi membranes that could be suppressed by PC-Sec14p, which also suppresses the uncontrolled vesiculation caused by the cytosolic subfraction. We propose that, by delivering PI to specific sites in the Golgi membrane near the necks of coated buds, PITP induces local changes in the organization of the lipid bilayer, possibly involving PI metabolites, that triggers the fusion of the ectoplasmic faces of the Golgi membrane necessary for the scission of COPI-coated vesicles.
