Search results for "Ribonucleotide"
showing 10 items of 104 documents
A nuclear juvenile hormone-binding protein from larvae of Manduca sexta: a putative receptor for the metamorphic action of juvenile hormone
1994
0027-8424 (Print) Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S.; A 29-kDa nuclear juvenile hormone (JH)-binding protein from the epidermis of Manduca sexta larvae was purified by using the photoaffinity analog for JH II ([3H]epoxyhomofarnesyldiazoacetate) and partially sequenced. A 1.1-kb cDNA was isolated by using degenerate oligonucleotide primers for PCR based on these sequences. The cDNA encoded a 262-amino acid protein that showed no similarity with other known proteins, except for short stretches of the interphotoreceptor retinoid-binding protein, rhodopsin, and human nuclear protein p68. Recombinant bacu…
Modulation of the nuclear-envelope nucleoside triphosphatase by poly(A)-rich mRNA and by microtubule protein.
1982
Nuclear envelopes contain a nucleoside triphosphatase which is thought to be involved in the supply of energy for nucleo-cytoplasmic RNA transport. This enzyme is stimulated most efficiently by poly(A) and to a lesser extent by poly(G) and poly(dT). Half-maximal stimulation of the enzyme from rat liver nuclei, which was associated with the poly(A)-specific endoribonuclease IV and was free from poly(A) polymerase and endoribonuclease V activity, was determined to occur at a concentration of 1.1 × 106 poly(A) molecules/nuclear ghost. Double-reciprocal plot analyses revealed a 2.8-fold stimulation of the enzyme by poly(A). Poly(A) in the hybrid form had no influence on the activity of the nucl…
Down-regulation of Glutathione and Bcl-2 Synthesis in Mouse B16 Melanoma Cells Avoids Their Survival during Interaction with the Vascular Endothelium
2003
B16 melanoma (B16M) cells with high GSH content show high metastatic activity. However, the molecular mechanisms linking GSH to metastatic cell survival are unclear. The possible relationship between GSH and the ability of Bcl-2 to prevent cell death was studied in B16M cells with high (F10) and low (F1) metastatic potential. Analysis of a Bcl-2 family of genes revealed that B16M-F10 cells, as compared with B16M-F1 cells, overexpressed preferentially Bcl-2 (approximately 5.7-fold). Hepatic sinusoidal endothelium-induced B16M-F10 cytotoxicity in vitro increased from approximately 19% (controls) to approximately 97% in GSH-depleted B16M-F10 cells treated with an antisense Bcl-2 oligodeoxynucl…
Suppression of the JNK Pathway by Induction of a Metabolic Stress Response Prevents Vascular Injury and Dysfunction
2008
Background— Oxidative injury and dysfunction of the vascular endothelium are early and causal features of many vascular diseases. Single antioxidant strategies to prevent vascular injury have met with mixed results. Methods and Results— Here, we report that induction of a metabolic stress response with adenosine monophosphate kinase (AMPK) prevents oxidative endothelial cell injury. This response is characterized by stabilization of the mitochondrion and increased mitochondrial biogenesis, resulting in attenuation of oxidative c-Jun N-terminal kinase (JNK) activation. We report that peroxisome proliferator coactivator 1α is a key downstream target of AMPK that is both necessary and suffici…
EFFECTS OF DEFIBROTIDE IN PATIENTS WITH CHRONIC DEEP INSUFFICIENCY. THE PROVEDIS STUDY
2004
Aim. In the present study the effect of defibrotide, an antithrombotic and profibrinolytic agent, was investigated in patients with chronic venous insufficiency (CVI) due to deep vein obstruction and/or reflux (chronic deep vein insufficiency, CDVI). Methods. The study was a multicenter, randomized, double blind placebo controlled trial in which only patients with CDVI confirmed by ultrasound were enrolled. All patients were treated with adequate elastic compression and randomized to receive either oral defibrotide (800 mg/die) or matching placebo for 1 year. Patients with active or previous leg ulcer were excluded. Results. A to…
Influence of therapeutic and toxic doses of neuroleptics and antidepressants on energy metabolism of the isolated perfused rat brain.
1973
The isolated perfused rat brain was used for a comparative study of the effects of promazine, imipramine, monodesmethyl promazine and desipramine on cerebral energy metabolism. After perfusion for 30 min or 1 h the brain levels of the following substrates and metabolites were estimated: P-creatine, creatine, ATP, ADP, AMP, glycogen, glucose, glucose-6-P, fructose diphosphate, dihydroxyacetone-P, pyruvate, lactate, α-ketoglutarate, and ammonia. Drug concentrations of 5·10−6 M and 10−5 M in the perfusion medium caused a significant decrease of glucose-6-P alone. When the drug concentration was raised to a toxic range (10−4 M), reflected in the EEG by the pattern of secondary discharges, an ac…
Suitability of the isolated perfused rat brain for studying effects on cerebral metabolism
1972
The concentrations of P-creatine, creatine, ATP, ADP, AMP, glycogen, glucose, glucose-6-P, fructose diphosphate, dihydroxyacetone-P, α-glycero-P, lactate and pyruvate were measured in the isolated perfused rat brain as well as in rat brain in vivo. Similar levels were observed in the isolated brain and in intact animals, and the values measured were in good accordance with those described in the literature. Only the pyruvate and lactate content were significantly higher in the isolated brain but the lactate/pyruvate ratio remained unchanged. An anesthetic or ischemia caused just the same effects on energy metabolism of the isolated rat brain as described for intact animals. Thus, 1.5 mM phe…
Targeting transcription factor Stat4 uncovers a role for interleukin-18 in the pathogenesis of severe lupus nephritis in mice
2011
Polymorphisms in the transcription factor Stat4 gene have been implicated as risk factors for systemic lupus erythematosus. Although some polymorphisms have a strong association with autoantibodies and nephritis, their impact on pathophysiology is still unknown. To explore this further we used signal transducers and activators of transcription 4 (Stat4) knockout MRL/MpJ-Fas(lpr)/Fas(lpr) (MRL-Fas(lpr)) mice and found that they did not differ in survival or renal function from Stat4-intact MRL-Fas(lpr) mice. Circulating interleukin (IL)-18 levels, however, were elevated in Stat4-deficient compared to Stat4-intact mice, suggesting that this interleukin might contribute to the progression of l…
Triphenyltin(IV) 2-[(E)-2-(aryl)-1-diazenyl]benzoates as anticancer drugs: Synthesis, structural characterization, in vitro cytotoxicity and study of…
2009
Summary: Triphenyltin(IV) complexes of composition [Ph3SnL 1H]n (1) and [Ph3SnL2H]n (2) (where L1H=2-[(E)-2-(3-formyl-4-hydroxyphenyl)-1-diazenyl] benzoate and L2H = 2-[(E)-2-(4-Hydroxy-5-methylphenyl)-1-diazenyl] benzoate) were synthesized and characterized by spectroscopic (1H, 13C and 119Sn NMR, IR, 119Sn Mössbauer) techniques in combination with elemental analysis. The molecular structures and geometries of the complexes (1 and 2) were fully optimized using the quantum mechanical method (PM3). Complexes (1 and 2) were found to exhibit stronger cytotoxic activity in vitro across a panel of human tumour cell lines viz., A498, EVSA-T, H226, IGROV, M19 MEL, MCF-7 and WIDR. The test compound…
Molecular basis of the interaction of novel tributyltin(IV) 2/4-[(E)-2-(aryl)-1-diazenyl] benzoates endowed with an improved cytotoxic profile: Synth…
2010
A series of tributyltin(IV) complexes based on 2/4-[(E)-2-(aryl)-1-diazenyl]benzoate ligands was synthesized, wherein the position of the carboxylate and aryl substituents (methyl, tert-butyl and hydroxyl) varies. The complexes, Bu(3)SnL(1-4)H (1-4), have been structurally characterized by elemental analysis and IR, NMR ((1)H, (13)C, and (119)Sn) and (119)Sn Mossbauer spectroscopy. All have a tetrahedral geometry in solution and a trigonal bipyramidal geometry in the solid-state, except for Bu(3)SnL(4)H (4) that was ascertained to have tetrahedral coordination by X-ray crystallography. Cytotoxicity studies were carried out on human tumor cell lines A498 (renal cancer), EVSA-T (mammary cance…